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Ethical Concerns in Personalized Medicine: BRCA1/2 Testing in Minors and Communication of Breast Cancer Risk

Reporter/Curator: Stephen J. Williams, Ph.D.

ethicspersonalizedmedicine-page1

Dealing with the unexpected: consumer responses to direct-access BRCA mutation testing[1]

Direct-to-consumer (DTC) genetic testing and genetic health information in 2007 with the advent of personalized testing services by companies who offered microarray-based genotyping of single-nucleotide-polymorphisms (SNP) which had strong correlations to disease risk.  Three companies started to offer such services directly to the consumer:

A common test which is offered analyzes the consumers BRCA1/2 mutation status.  Three mutations in the BRCA gene are known to predispose women to hereditary breast and ovarian cancer: BRCA1 185delAG, BRCA1 538insC, and BRCA2 617delT.  These BRCA1 mutation confer a 60% breast cancer risk and a 40% risk of ovarian cancer while the BRCA2 mutation confers a breast cancer risk of 50% and 20% risk of ovarian cancer.

However, the commercial availability of this genetic disease-risk associated testing has led to certain ethical issues concerning communication and responses of risk information by:

  1. Consumers who request BRCA1/2 testing (focus of the Francke article
  2. BRCA1/1 testing and communication of results to minors and relatives (Bradbury: see below)

There has been much opinion, either as commentary in literature, meeting proceedings, or communiques from professional societies warning that this type of “high-impact” genetic information should not be given directly to the consumer as consumers will not fully understand the information presented to them, be unable to make proper risk-based decisions, results could cause panic and inappropriate action such as prophylactic oophorectomy or unwarranted risk-reduction mastectomy, or false reassurance in case of negative result and reduced future cancer screening measures taken by the consumer.  However, there have been few studies to investigate these concerns.

A report by Dr. Uta Francke in the open access journal PeerJ, assesses and quantifies the emotional and behavioral reactions of consumers to their 23andMe Personal Genome Service® report of the three BRCA mutations known to be associated with high risk for breast/ovarian cancer.  One hundred thirty six (136) individuals, who tested positive for BRCA1 and/or BRCA2 mutations as well as 160 users of the service, who tested mutation-free were invited to participate in phone interviews addressing personal and family history of cancer, decision and timing of viewing the BRCA report, recollection of results, emotional responses, perception of personal cancer risk, information sharing, and actions taken.  Thirty two (32) mutation carriers (16 female and 16 male) and 31 non-carriers responded to the phone questionnaire.

Questions were based on the following themes:

  1. When you purchased the 23andME Personal Genome Service® were you aware that it included testing for mutations that predispose to breast and ovarian cancer?
  2. Were you aware that having Ashkenazi Jewish ancestry influences your risk of carrying one of the three mutations?
  3. Have you or a first or second degree relative been diagnosed with breast, ovarian or any other cancer?
  4. What did you learn from your results?
  5. Were you surprised by the result?
  6. How did you feel about this information (extremely, moderately, somewhat upset or extremely relieved)?

Results:  Eleven women and 14 men had received an unexpected result that they are carriers of one of the three mutations however none of them reported extreme anxiety and only four reported moderate anxiety which did not last long.  Participants were at least 8 years of age. Five women and six men described their reaction as neutral.  Most carrier women sought medical advice and four underwent risk-reducing procedures. Some to the male carriers felt burdened to share their test results with their female relatives, which led to additional screenings of relatives.  Almost all of the mutation-positive customers appreciated learning their BRCA mutational status.

Other highlights of the results include:

  • More women got tested if they had a first or second degree relative previously diagnosed with breast/ovarian cancer
  • Ten mutation-positive individuals who were surprised at the test results cited the lack of family history of breast/ovarian cancer as the reason for their surprise.  The rest who were surprised at their positive test results believed that the frequency of these mutations were low in the general population so they shouldn’t have been affected.
  • For the mutation-positive group, none of the 32 reported as being “extremely upset”.
  • Interestingly, on male who learned, for the first time, he was a positive carrier for BRCA mutation, reported feeling “relieved” because his daughter who was also tested by 23andMe had not acquired his mutation.

A brief interview with Dr. Francke follows:

Q:     In your results you had noted that none of the mutation carriers showed extreme anxiety about their reports however there were many of Ashkenazi descent who was well aware of the increased risk to breast cancer.  In another study by Dr. Angela Bradbury, anxieties and communication to their children depended on mutation status and education status.  Do you feel that most women in your study were initially aware they could be in a high risk category for cancer, whether breast, ovarian, or other?

Dr. Francke:   As we show in Table 1, 6 of 16 women and 6 of 16 men who found out that they were BRCA mutation carriers had not been aware that being of Ashkenazi descent confers an increased risk of breast/ovarian cancer.  In Table S1, we show that 6 of these 32 people did not self-identify as Ashkenazi.
Q:     The reporting and communication of test results to offspring and genetic testing of offspring as a result of positive tests has been under much debate.  I had noticed that there was a high proportion of relatives who went for screening after learning of a family members BRCA testing, whether it showed a mutation or not.  Some studies have shown that offspring of carriers may misinterpret genetic testing results and take inappropriate action, such as considering having early testing  before age 25.  It appears some anxiety may be due to misinformation and lack of genetic counseling.  Should these test results be considered in guidelines for oncologist such as NCCN guidelines with respect to informing family members using genetic counselors as an intermediary?

Dr. Francke:    The “high proportion of relatives who went for screening after learning of a family member’s BRCA testing”, were only those related to a BRCA-positive person. Most of the BRCA testing of relatives was done through health care providers at Myriad as these people were eligible for insurance coverage of the test. In our interviews we found no evidence for inappropriate action of carriers or non-carriers. With one exception, we found no evidence for misinterpretation or “anxiety due to lack of genetic counseling”.  In our online reports we recommend genetic counseling for all customers who have questions about their results.

Q:     I was also particularly interested the male carrier felt a heightened burden to tell their offspring.  This has been suggested in other studies.  I would assume the mothers and not the fathers would feet more pressure to tell their children.  Is there a reason for this?
Dr. Francke:     The heightened burden reported by the male carriers was mostly about the realization of the risk for their daughters, not so much about to telling their offspring.  Female carriers were primarily concerned about their own health risk and management, and decision-making about preventive measures – therefore, the risk for offspring appeared to be of secondary concern for them.

However, the availability of this type of predictive genetic testing for hereditary cancer has raised some ethical issues regarding the communication of risk and genetic results to family members and especially offspring, specifically whether informing minors would incur unnecessary testing, anxiety among minors of parents who tested positive for genetic risk-factors, or even premature risk-reduction surgeries or medical interventions.

The aforementioned ethical issues concerning communicating results of BRCA mutational testing to offspring was addressed by two large studies conducted by Dr. Angela Bradbury M.D. and colleagues at Fox Chase Cancer Center Family Risk Assessment Program (now she is at University of Pennsylvania) and University of Chicago Cancer Risk Clinic.  These studies evaluated the parental opinions regarding BRCA1/2 testing of minors, and how parents communicate BRCA1/2 genetic testing with their children.

In the JCO article (Parent Opinions Regarding the Genetic Testing of Minors for BRCA1/2)[2], Bradbury and colleagues used semistructured interviews (yes/no questions and open-ended questions) of 246 parents at Fox Chase and University of Chicago, who underwent BRCA1/2 whether they supported testing of minors in general and testing of their own offspring.  Parents were asked, “If you were deciding, do you think children under 18 years old should be given the opportunity to be tested” and followed by the open-ended question: “Why do (don’t) you support the genetic testing of minors for BRCA1/2?”.

Results:  In response to the first question (Would you support testing in minors) 37% of parents supported testing of minors in the general population.  The follow-up open-ended question revealed that 4% support testing minors in some or all circumstances.  This decision was independent of parent sex or race.  44% of parents would test their own offspring.  Parents who opposed testing in minors thought testing would cause fear and anxiety for their children but those who supported unconditional testing (regardless of whether they were positive for the BRCA mutation or not) mentioned that the medical information would foster better health behaviors in their offspring.  21% of parents who opposed testing minors, in general, actually supported testing of their own children.  Interestingly parents who tested positive for the BRCA1 overwhelmingly (64%) opposed testing of minors, in general.  In addition, statistical analysis of the open-ended questions revealed that parents who did not have a college degree, had a negative test result, and were non white favored testing of their own children.  The authors had suggested larger studies before any guidelines were given as to whether testing in minors of BRCA mutation carriers should be standard.

In a recent publication by Dr. Bradbury and colleagues (Knowledge and perceptions of familial and genetic risks for breast cancer risk in adolescent girls)[3],  studied how adolescent girls understood and responded to breast cancer risk by interviewing 11-19 year-old girls at high-risk and population-risk for breast cancer. Although most girls said they were aware of increased risk because either a family member had or was predisposed to breast cancer (66 %) only 17 % of girls were aware of BRCA1/2 genes. Mother was the most frequently reported source of information for breast cancer among both high-risk (97 %) and population-risk (89 %) girls.  The study also showed that most girls who believe they are at high-risk could alter their lifestyles or change dietary habits to lower their risk.

In an adjacent study in the journal Cancer[4], Bradbury and colleagues at Fox Chase Cancer Center had gauged the frequency with which parents had told their children of their BRCA1/2 teat results and how their children felt about the results.

When parents disclose BRCA1/2 test results: Their communication and perceptions of offspring response[4]

Semi-structured interviews were conducted with parents who had BRCA1/2 testing and at least 1 child <25 YO.  A total of 253 parents completed interviews (61% response rate), reporting on 505 offspring. Twenty-nine percent of parents were BRCA1/2 mutation carriers. Three hundred thirty-four (66%) offspring learned of their parent’s test result. Older offspring age (P ≤ .01), offspring gender (female, P = .05), parents’ negative test result (P = .03), and parents’ education (high school only, P = .02) were associated with communication to offspring. The most frequently reported initial offspring responses were neutral (41%) or relief (28%). Thirteen percent of offspring were reported to experience concern or distress (11%) in response to parental communication of their test results. Distress was more frequently perceived among offspring learning of their parent’s BRCA1/2 positive or variant of uncertain significance result.

CONCLUSIONS:

Many parents communicate their BRCA1/2 test results to young offspring. Parents’ perceptions of offspring responses appear to vary by offspring age and parent test result. A better understanding of how young offspring respond to information about hereditary risk for adult cancer could provide opportunities to optimize adaptive psychosocial responses to risk information and performance of health behaviors, in adolescence and throughout an at-risk life span.

Below is an excellent article by Steven Reinberg from HealthDay interviewing Dr. Angela Bradbury concerning their JCO study: (reported for ABC News at http://abcnews.go.com/Health/Healthday/story?id=4508346&page=1#.UVNJUVef2RM)

Many Parents Share Genetic Test Findings With Kids

By Steven Reinberg
HealthDay Reporter

Mar. 23

FRIDAY, Aug. 17 (HealthDay News) — As genetic testing for diseases becomes more commonplace, the impact of those findings on family members may be underestimated, researchers say.

For instance, some women who discover they have the BRCA gene mutation, which puts them at higher risk for breast cancer, choose to tell their children about it before the children are old enough to understand the significance or deal with it, a new study found.

“Parents with the BRCA mutation are discussing their genetic test results with their offspring often many years before the offspring would need to do anything,” said study author Dr. Angela Bradbury, director of the Fox Chase Cancer Center’s Family Risk Assessment Program, in Philadelphia.

According to Bradbury, more than half of parents she surveyed told their children about genetic test results. Some parents reported that their children didn’t seem to understand the significance of the information, and some had initial negative reactions to the news.

“A lot of genetic information is being shared within families and there hasn’t been a lot of guidance from health-care professionals,” Bradbury said. “While this genetic risk may be shared accurately, there is risk of inaccurate sharing.”

In the study, Bradbury’s team interviewed 42 women who had the BRCA mutation. The researchers found that 55 percent of parents discussed the finding and the risk of breast cancer with at least one of their children who was under 25.

Also, most of the women didn’t avail themselves of the services of a doctor or genetic counselor in helping to tell their children, Bradbury’s group found.

Bradbury is concerned that sharing genetic information with young children can create anxiety. “The children could be overly concerned about their own risk at a time when there is nothing that they need to do,” she said.

But, she added, “it may be possible that sharing may be good for children in adapting to this information.”

The findings are published in the Aug. 20 issue of the Journal of Clinical Oncology.

The lack of definitive data on when — or if — to discuss genetic test results with children is a real problem, Bradbury said.

“As we move genetic testing forward for cancer or other illnesses, we have to consider the context of the whole family and focus our counseling to the whole family, and not just the person who comes in for testing,” Bradbury said. “We should learn more about how and when we should talk to children about this, so that we can promote healthy behaviors without causing too much anxiety for the offspring.”

Barbara Brenner, executive director of Breast Cancer Action, agreed that the psychological component of genetic testing needs more attention.

“This is the tip of a very scary iceberg,” Brenner said. “We don’t know the psychological consequences [of BRCA testing], not only to the person who has the test, but to her family members.”

Brenner thinks guidelines to help parents deal with this information are needed. So is help from doctors and genetic counselors in counseling family members, especially children, she added.

LEGACY (Lessons in Epidemiology and Genetics of Adult Cancer from Youth), supported by the National Institutes of Health. This study will follow the girls prospectively in order to evaluate epidemiologic and epigenetic pathways of childhood exposures in relation to pubertal development, age at menarche, breast tissue characteristics, biomarkers of exposure, genomic DNA methylation, and the psychosocial impact of increased breast cancer susceptibility in 6-13 YO girls. http://legacygirlsstudy.org/

 

1.         Francke U, Difamco C, Kiefer AK, Eriksson N, Moiseff B, Tung JY, Mountain JL: Dealing with the unexpected: consumer responses to direct-access BRCA mutation testing. PeerJ 2013:1-21.

2.         Bradbury AR, Patrick-Miller L, Egleston B, Sands CB, Li T, Schmidheiser H, Feigon M, Ibe CN, Hlubocky FJ, Hope K et al: Parent opinions regarding the genetic testing of minors for BRCA1/2. Journal of clinical oncology : official journal of the American Society of Clinical Oncology 2010, 28(21):3498-3505.

3.         Bradbury AR, Patrick-Miller L, Egleston BL, Schwartz LA, Sands CB, Shorter R, Moore CW, Tuchman L, Rauch P, Malhotra S et al: Knowledge and perceptions of familial and genetic risks for breast cancer risk in adolescent girls. Breast cancer research and treatment 2012, 136(3):749-757.

4.         Bradbury AR, Patrick-Miller L, Egleston BL, Olopade OI, Daly MB, Moore CW, Sands CB, Schmidheiser H, Kondamudi PK, Feigon M et al: When parents disclose BRCA1/2 test results: their communication and perceptions of offspring response. Cancer 2012, 118(13):3417-3425.

Sources:

http://abcnews.go.com/Health/Healthday/story?id=4508346&page=1#.UVNJUVef2RM

Other article on Ethics and Personalized Medicine on the site include:

Genomics in Medicine- Tomorrow’s Promise

Attitudes of Patients about Personalized Medicine

Genomics & Ethics: DNA Fragments are Products of Nature or Patentable Genes?

Volume One: Genomics Orientations for Individualized Medicine

Directions for Genomics in Personalized Medicine

The Way With Personalized Medicine: Reporters’ Voice at the 8th Annual Personalized Medicine Conference,11/28-29, 2012, Harvard Medical School, Boston, MA

Highlights from 8th Annual Personalized Medicine Conference, November 28-29, 2012, Harvard Medical School, Boston, MA

Clinical Genetics, Personalized Medicine, Molecular Diagnostics, Consumer-targeted DNA – Consumer Genetics Conference (CGC) – October 3-5, 2012, Seaport Hotel, Boston, MA

Genetic basis of Complex Human Diseases: Dan Koboldt’s Advice to Next-Generation Sequencing Neophytes

2013 Genomics: The Era Beyond the Sequencing of the Human Genome: Francis Collins, Craig Venter, Eric Lander, et al.

Improving Mammography-based imaging for better treatment planning

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Imaging Guided Cancer-Therapy – a Discipline in Need of Guidance

 Author – Writer: Dror Nir, PhD

The use of imaging in cancer management is broadly established. During the past two decades, advancements in imaging; image quality, precision and reproducibility lead to introduction of localized, minimally invasive treatments of cancer lesions.

 A statement-paper, published online: 17 January 2013: Radiologists’ leading position in image-guided therapy, which presents the thoughts of the Image-Guided Therapy Working Group within the Research Committee of the European Society of Radiology, give hope that the policy-makers in the European radiology society are becoming aware of the need to guide this process.

Although the authors are addressing imaging guided therapy (IGT) in its broad sense, most of their examples are related to treatment of cancer. The main reason for provided for being concerned with what is happening in this domain is: “This means that the planning, performing and monitoring, as well as the control of the therapeutic procedure, are based and dependent on the “virtual reality” provided by imaging investigations.”

The most interesting points raised by the authors are:

 1. The realization that IGT is involving many “non-radiologist”, and this fact cannot be ignored: “This role is mainly driven by the sophisticated opportunities offered by medical computing and radiological image guidance with regard to precision and minimal invasiveness [2]. However, the impact of radiology on the regulatory medico-legal, technical and radioprotection issues in this field have not yet been defined. Since an increasing number of procedures will probably be performed by non-radiologists, several main questions have to be addressed:

  • How should the radiology training requirements for non-radiologists be provided?
  • How should the technical and radioprotection related responsibilities for radiological imaging systems used by non-radiologists be organised?
  • How should radiologists be involved in the practical routine use of non-radiological image-guided procedures in clinical practice?

Considering the almost pan-European medical reality with decreasing staff resources and increasing diversification and subspecialisation, radiologists have to stress the fact that within a cooperative, goal-oriented and multidisciplinary environment, the specialty-specific knowledge should confer upon radiologists a significant impact on the overall responsibility for all imaging-related processes in various non-radiological specialties (such as purchase, servicing, quality management, radiation protection and documentation). Furthermore, radiologists should take responsibility for the definition and compliance with the legal requirements regarding all radiological imaging, especially if non-radiologists have to be trained in the use of imaging technology for guidance of therapy.”

2. Quality assurance and service standards needs to be established; “Performing IGT necessitates specific quality management tools for establishing standards and maintaining levels of excellence…. A European task force group on IGT might be necessary to further develop certification guidelines and establish requirements for IGT practice according to known standards, focused on common recommendations and certification guidelines.”

3. Controlling the process of introducing new medical devices into this niche-market: “IGT research can be broadly divided into two categories, target specific research (e.g. the type of tumour or vascular lesion by imaging biomarkers) and technical research (e.g. evaluation of a new device or procedure). Understanding the efficacy and application of new and emerging technologies is a critical first step, which then leads to target-specific research. The focus of this research is aimed at understanding when, where and in whom the therapy can provide clear clinical benefit and how to use IGT in conjunction with, or as an alternative to, more established therapies. This also clearly includes research on the development and implementation of imaging biomarkers, defined as objectively measured indicators of normal biological processes, pathological changes, or responses to a therapeutic intervention [9]…..

4. An unusual remark is made in respect to the way new devices are introduced: “Clinical specialists who lack the knowledge and expertise required to champion IGT and who are often already over-committed in pursuing their own research goals often dominate committees in control of other funding streams….”

5. Clear recognition that “health-care costs” is of outmost importance: “Demonstration of the cost effectiveness of IGT methods of treatment and targeting with formal quantification of financial as well as patient benefit would encourage their wider adoption. In a broad perspective, health technology assessment (HTA) might be the way for the systematic evaluation of health-relevant IGT procedures and methods, the effectiveness, safety and economic viability of a health intervention, as well as its social, ethical, legal and organisational effects; and for providing a basis for decisions in the health system.”

 References

1.

Solomon SB, Silverman SG (2010) Imaging in interventional oncology. Radiology 257(3):624–40PubMedCrossRef

2.

Levy MA, Rubin DL (2011) Current and future trends in imaging informatics for oncology. Cancer J 17(4):203–10PubMedCrossRef

3.

Council Directive 97/43 Euratom, on health protection of individuals against the dangers of ionizing radiation in relation to medical exposure, and repealing Directive 84/466 Euratom, 1997

4.

DIMOND. Measures for optimising radiological information and dose in digital imaging and interventional radiology. European Commission. Fifth Framework Programme. 1998–2002

5.

SENTINEL. Safety and efficacy for new techniques and imaging using new equipment to support European legislation. European Coordination Action. 2005–2007

6.

http://www.sirweb.org/about-us/IRSocietiesAroundTheWorld.shtml

7.

UNSCEAR (2000) Sources and effects of ionising radiation. United Nations Scientific Committee on the Effects of Atomic Radiation Report to the General Assembly with Scientific Annexes

8.

The 2007 recommendations of the international commission on radiological protection

9.

European Society of Radiology (2010) White paper on imaging biomarkers. Insights Imaging 1(2):42–45CrossRef

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Accurate Identification and Treatment of Emergent Cardiac Events

Accurate Identification and Treatment of Emergent Cardiac Events

Author: Larry H Bernstein, MD, FCAP
In the immediately preceding article, I discussed the difficulties in predicting long-term safety for developing drugs, and the cost of failure in early identification.

It is not the same scale of issue as for the patient emergently presenting to the ED. Despite enormous efforts to reduce the development of and the complications of acute ischemia related cardiac events, the accurate diagnosis of the patient presenting to the emergency room is still, as always, reliant on clinical history, physical examination, effective use of the laboratory, and increasingly helpful imaging technology. The main issue that we have a consensus agreement that PLAQUE RUPTURE is not the only basis for a cardiac ischemic event. The introduction of  high sensitivity troponin tests has made it no less difficult after throwing out the receiver-operator characteristic curve (ROC) and assuming that any amount of cardiac troponin released from the heart is pathognomonic of an acute ischemic event.  This has resulted in a consensus agreement that

  • ctn measurement at a coefficient of variant (CV) measurement in excess of 2 Std dev of the upper limit of normal is a “red flag”
  • signaling AMI? or other cardiomyopathic disorder

This is the catch.  The ROC curve established AMI in ctn(s) that were accurate for NSTEMI – (and probably not needed with STEMI or new Q-wave, not previously seen) –

  1. ST-depression
  2. T-wave inversion
    • in the presence of other findings
    • suspicious for AMI

Wouldn’t it be nice if it was like seeing a robin on your lawn after a harsh winter?  Life isn’t like that.  When acute illness hits the patient may well present with ambiguous findings.   We are accustomed to relying on

  1. clinical history
  2. family history
  3. co-morbidities, eg., diabetes, obesity, limited activity?, diet?
    1. stroke and/or peripheral vascular disease
    2. hypertension and/or renal vascular disease
    3. aortic atherosclerosis or valvular heart disease
      • these are evidence, and they make up syndromic classes
  4. Electrocardiogram – 12 lead EKG (as above)
  5. Laboratory tests
    1. isoenzyme MB of creatine kinase (CK)… which declines after 12-18 hours
    2. isoenzyme-1 of LD if the time of appearance is > day-1 after initial symptoms (no longer used)
    3. cardiac troponin cTnI or cTnT
      • genome testing
      • advanced analysis of EKG

This may result in more consults for cardiologists, but it lays the ground for better evaluation of the patient, in the long run.  When you look at the amount of information that has to be presented to the physician, there is serious need for improvement in the electronic medical record to benefit the patient and the caregivers.  Recently, we have a publication on a new test that has been evaluated, closely related to the C-reactive protein (CRP), a test that has generated much discussion over the effect of treatment for patients who have elevated CRP in the absence of increased LDL cholesterol, diabetes, or obvious atherosclerotic comorbidities.  The serum pentraxin 3 test is related to cell mediated immunity, and an evaluation has been published in the Journal of Investigative Medicine.

Journal of Investigative Medicine Feb 2013; 61 (2): 278–285.
http://dx.doi.org/10.231/JIM.0b013e31827c2971

Serum Pentraxin 3 Levels Are Associated With the Complexity and Severity of Coronary Artery Disease in Patients With Stable Angina Pectoris
Karakas, Mehmet Fatih MD*; Buyukkaya, Eyup MD*; Kurt, Mustafa MD*; et al.
From the Departments of Cardiology and,Clinical Biochemistry, Mustafa Kemal University, Tayfur Ata Sokmen Medical School, Hatay, Turkey.
Reprints: Mehmet Fatih Karakas, MD, Antakya 31005, Turkey. E-mail: mfkarakas@hotmail.com.

Abstract
Background: Atherosclerosis is a complex inflammatory process. Although pentraxin 3 (PTX-3), a newly identified inflammatory marker, was associated with adverse outcomes in stable angina pectoris,

  • an association between PTX-3 and the complexity of coronary artery disease (CAD) has not been reported.

The aim of the present study is to assess

  • the association between the level of PTX-3 and
  • the complexity and severity of CAD assessed with
  • SYNTAX and Gensini scores in patients with stable angina pectoris.

Methods: The study population is 2 groups:

  • 161 patients with anginal symptoms and evidence of ischemia
    • who underwent coronary angiography and
  • 50 age- and sex- matched control subjects without evidence of ischemia .

Patients were grouped into 3 groups according to the complexity and severity of coronary lesions

  • assessed by the SYNTAX score (30 patients with a SYNTAX score of 0 were excluded).

Serum PTX-3 and high-sensitivity C-reactive protein (hs-CRP) levels were measured in both groups.

Results: The PTX-3 levels demonstrated

  • an increase from low to high SYNTAX groups (r = 0.72, P < 0.001).

Whereas the low SYNTAX group had statistically significantly higher PTX-3 levels when compared with the control group (0.50 ± 0.01 vs 0.24 ± 0.01 ng/mL, P < 0.001),

  • the hs-CRP levels were not different (0.81 ± 0.42 vs 0.86 ± 0.53 mg/dL, P = 0.96).
  • but  the intermediate SYNTAX group had higher hs-CRP levels compared with the low SYNTAX group (1.3 ± 0.66 vs 0.86 ± 0.53 mg/dL, P = 0.002).

Serum PTX-3 levels and hs-CRP levels were both correlated with the SYNTAX scores and Gensini scores (for SYNTAX: r = 0.87 [P < 0.001] and r = 0.36 [P = 0.01]; for Gensini: r = 0.75 [P < 0.001] and r = 0.27 [P = 0.002], respectively), and

  • according to the results of univariate and multivariate analyses, for “intermediate and high” SYNTAX scores, age, diabetes mellitus, low-density lipoprotein cholesterol, hs-CRP, and PTX-3
  • were found to be independent predictors, whereas
  • for the presence of “high” SYNTAX score only PTX-3 was found to be an independent predictor.
  • The receiver operating characteristic curve analysis further revealed that the PTX-3 level was
    • a strong indicator of high SYNTAX score with an area under the curve of 0.91 (95% confidence interval, 0.86–0.96).

Conclusions: Pentraxin 3, a novel inflammatory marker, was more tightly associated with the complexity and severity of CAD than hs-CRP and

    • it was found to be an independent predictor for high SYNTAX score.

The association between atherosclerosis and inflammation has been more understood during recent years. Currently, atherosclerosis is considered as a complex inflammatory process in which

    • leukocytes and inflammatory markers are involved.1

Several inflammatory markers

  1.  high-sensitivity C-reactive protein (hs-CRP),
  2. fibrinogen, and
  3. complement C3…. are associated with cardiovascular events.1–5

Pentraxin 3 (PTX-3), that resembles CRP both in structure and function,1 is produced both by

  • hematopoietic cells such as macrophages, dendritic cells, neutrophils, and by
  • nonhematopoietic cells such as fibroblasts and vascular endothelial cells.2

Plasma PTX-3 levels may be elevated in patients with

  1. vasculitis,6
  2. acute myocardial infarction,7,8 and
  3. systemic inflammation or sepsis,9
  4. psoriasis,
  5. unstable angina pectoris, and
  6. heart failure.10–13

Dubin et al14 reported that PTX-3 levels are associated with with adverse outcomes in stable angina pectoris (SAP). Despite reports about the association of PTX-3 and coronary artery disease (CAD),

an association between the level of PTX-3 and the complexity and severity of CAD is not established.15,16 Thus, the aim of this study was

  • to assess the association between the level of PTX-3 and the complexity and severity of CAD assessed with SYNTAX and Gensini scores in SAP patients.

MATERIALS AND METHODS

Of 211 patients were prospectively recruited,  161 SAP patients with evidence of ischemia (positive treadmill or myocardial perfusion scan) underwent coronary angiography for suspected CAD, and 50 age- and sex- matched outpatient subjects with a negative treadmill or myocardial perfusion scan test were taken as the control group. Patients were excluded if they had

  •  acute coronary syndrome
  • history of previous myocardial infarction;
  • coronary artery bypass grafting or percutaneous coronary intervention;
  • secondary hypertension (HT);
  • renal failure;
  • hepatic failure;
  • chronic obstructive lung disease and/or
  • manifest heart disease, such as
    • cardiac failure (left ventricular ejection fraction <50%),
    • atrial fibrillation, and
    • moderate to severe cardiac valve disease; and
    • SYNTAX score of zero

Similarly, patients were excluded with

  • infection,
  • acute stress, or chronic systemic inflammatory disease and
  • those who had been receiving medications affecting the number of leukocytes .

Thirty patients were excluded from the study because the coronary angiograms revealed normal coronary arteries (SYNTAX score of 0). All the participants included in the study were informed about the study, and they voluntarily consented to participate. The Serum PTX-3 level was measured on blood samples collected after 12-hour fast just prior to coronary angiography and kept at −80°C until the assays were performed. PTX3 was measured by enzyme immunoassay (EIA) using quantitative kit (human PTX-3/TSG-14 immunoassay, DPTX30; R&D Systems, Inc, Minneapolis, MN). The intra-assay and interassay coefficients of variation ranged from 3.8% to 4.4% and 4.1% to 6.1%, respectively (minimum detectable concentration, 0.025 ng/mL). High-sensitivity CRP was measured in serum by EIA (Immage hs-CRP EIA Kit; Beckman Coulter Inc, Brea, CA). Transthoracic echocardiography was performed, and biplane Simpson’s ejection fraction (%) was calculated before coronary angiography. Hypertension was defined as having at least 2 blood pressure measurements greater than 140/90 mm Hg or using antihypertensive drugs, whereas diabetes mellitus (DM) was defined as having at least 2 fasting blood sugar measurements greater than 126 mg/dL or using antidiabetic drugs. Smoking was categorized into current smokers and nonsmokers. Nonsmokers included ex-smokers who had quit smoking for at least 6 months before the study. Body mass index (BMI) values were calculated based on the height and weight of each patient. Medications used before the coronary angiography were noted. The study was approved by the local ethics committee.
SYNTAX and Gensini Scores
To grade the complexity of CAD, the SYNTAX score was used. Each coronary lesion with a stenosis diameter of 50% or greater in vessels of 1.5 mm or greater was scored. Parameters used in the SYNTAX scoring are shown in Table 1. The latest online updated version (2.11) was used in the calculation of the SYNTAX scores (www.syntaxscore.com).17 The SYNTAX score was classified as follows:

  1. low SYNTAX score (≤22),
  2. intermediate SYNTAX score (23–32)
  3. high SYNTAX score (≥33).

Table 1   http://images.journals.lww.com/jinvestigativemed/LargeThumb.00042871-201302000-00007.TT1.jpeg

The severity of CAD was determined by the Gensini score, which

  • measures the extent of coronary stenosis according to degree and location.18

In the Gensini scoring system,

  • larger segments are more heavily weighted ranging from 0.5 to 5.0
    • left main coronary artery × 5;
    • proximal segment of the left anterior descending coronary artery [LAD] × 2.5;
    • proximal segment of the circumflex artery × 2.5;
    • midsegment of the LAD × 1.5;
    • right coronary artery distal segment of the LAD,
    • posterolateral artery, and obtuse marginal artery × 1;
    • and others × 0.5.

The narrowing of the coronary artery lumen is rated

  1. 2 for 0% to 25% stenosis,
  2. 4 for 26% to 50%,
  3. 8 for 51% to 75%,
  4. 16 for 76% to 90%,
  5. 32 for 91% to 99%,
  6. 64 for 100%.

The Gensini index is the sum of the total weights for each segment. All angiographic variables of the SYNTAX and Gensini score were computed by

  • 2 experienced cardiologists who were blinded to the procedural data and clinical outcomes.

The final decision was reached by consensus when a conflict occurred.The number of diseased vessels with

  • greater than 50% luminal stenosis was scored from 1 to 3 (namely, 1-, 2-, or 3-vessel disease), and
  • a lesion greater than 50% in the left main coronary artery was regarded as a 2-vessel disease.

Statistical Analyses

Statistical analyses were conducted with SPSS 17 (SPSS Inc, Chicago, IL) software package program.
Continuous variables were expressed as mean ± SD or median ± interquartile range values, whereas categorical variables were presented as percentages.
The differences between normally distributed numeric variables were evaluated by Student t test or 1-way analysis of variance, whereas

  • non–normally distributed variables were analyzed by Mann-Whitney U test or Kruskal-Wallis variance analysis as appropriate.

χ2 Test was used for the comparison of categorical variables. Pearson test was used for correlation analysis.
To determine the independent predictors of “intermediate and high” SYNTAX scores and only “high” SYNTAX scores,

  • 2 different sets of univariate and multivariate analyses were performed
    • (in the first model SYNTAX cutoff was 22, whereas
    • in the second model SYNTAX cutoff was 33).

The standardized parameters that were found to have a significance (P < 0.10) in the univariate analysis were evaluated by stepwise logistic regression analysis.
Ninety-five percent confidence interval (CI) and odds ratio (OR) per SD increase were presented together. Interobserver and intraobserver variability for SYNTAX scores

  • was done by Bland-Altman analysis.

An exploratory evaluation of additional cut points was performed using the receiver operating characteristic (ROC) curve analysis.
All the P values were 2-sided, and a P < 0.05 was considered as statistically significant.
RESULTS
Baseline Characteristics
In total, 181 patients (50.2 ± 6.5 years, 52.5% were composed of males) were included in the study. Baseline clinical, angiographic, and laboratory characteristics of the patients
relative to SYNTAX score groups are shown in Table 2. Age, sex, HT, DM, BMI, and medication were not different between the groups. Baseline clinical and laboratory characteristics
of patients according to PTX-3 quartiles are shown in Table 3. The Bland-Altman analysis revealed that the degrees of intraobserver and interobserver variability for SYNTAX score
and Gensini score readings were 5% and 6% for SYNTAX and 8% and 9% for Gensini,
respectively.
Table 2   http://images.journals.lww.com/jinvestigativemed/Original.00042871-201302000-00007.TT2.jpeg
Table 3   http://images.journals.lww.com/jinvestigativemed/Original.00042871-201302000-00007.TT3.jpeg

The PTX-3 levels demonstrated an increase from the low SYNTAX group to the high SYNTAX group (r = 0.87, P < 0.001).
The low SYNTAX group had statistically significantly higher PTX-3 levels when compared with the control group (0.50 ± 0.01 vs 0.24 ± 0.01 ng/mL, P < 0.001); similarly,
the PTX-3 levels were higher in the high SYNTAX group than in both

  • the intermediate SYNTAX group (0.84 ± 0.08 vs 0.55 ± 0.01 ng/mL, P < 0.001) and
  • the low SYNTAX group (0.84 ± 0.08 vs 0.50 ± 0.01 ng/mL, P < 0.001).
  • there was no difference in levels of PTX-3 between the low and the intermediate SYNTAX group (0.50 ± 0.01 vs 0.55 ± 0.01 ng/mL, P = 0.09).

On the other hand, there was no difference in levels of hs-CRP between the control and the low SYNTAX group (0.81 ± 0.42 vs 0.86 ± 0.53 mg/dL, P = 0.96).
The intermediate SYNTAX group had statistically significantly higher hs-CRP levels

  • compared with the low SYNTAX group (1.3 ± 0.66 vs 0.86 ± 0.53 mg/dL, P = 0.002);
  • the hs-CRP levels were not different between the high SYNTAX group
    • and the intermediate SYNTAX group. (1.3 ± 0.66 vs 1.3 ± 0.43 mg/dL, P = 0.99).

Univariate correlation analysis revealed a positive correlation between serum PTX-3 levels and hs-CRP levels with

  • the SYNTAX and Gensini scores
    • for SYNTAX: r = 0.87 [P < 0.001] and r = 0.36 [P = 0.01];
    • for Gensini: r = 0.75 [P < 0.001] and r = 0.27 [P = 0.002],  (Fig. 1).

In addition to that, the Gensini and SYNTAX scores are found to be well correlated with each other (r = 0.80, P < 0.001).
When the SYNTAX score was taken as continuous variable, multivariate linear regression analysis revealed that

  • the SYNTAX score was correlated with PTX-3 and hs-CRP (for PTX-3: β = 0.84 [P < 0.001]; hs-CRP: β =0.08 [P = 0.032]).

Figure 1   http://images.journals.lww.com/jinvestigativemed/Original.00042871-201302000-00007.FF1.jpeg

For determining the predictors of intermediate and high SYNTAX scores and only-high SYNTAX scores,

  • 2 different sets of univariate and multivariate analyses were performed among the patients who underwent coronary angiography.

For predicting the intermediate and high SYNTAX scores, the SYNTAX score was dichotomized into

  • high (score ≥22) and
  • low (<22) groups,

whereas for predicting the only-high SYNTAX scores, the SYNTAX score was dichotomized into

  • 2 groups with a score of 33 or greater and a score of less than 33.

In the first multivariate analysis (where SYNTAX cutoff was 22), the parameters showing significance in the univariate analysis

  • age,
  • sex,
  • HT,
  • DM,
  • low-density lipoprotein cholesterol [LDL-C],
  • hs-CRP,
  • PTX-3

were evaluated by multivariate analysis to determine the

  • independent predictors of intermediate and high SYNTAX scores.

In the univariate analysis, higher values of

  • age (OR, 1.5 [95% CI, 1.1–2.0]; P = 0.01),
  • LDL-C (OR, 1.3 [95% CI, 0.98–1.8]; P = 0.068),
  • hs-CRP (OR, 2.6 [95% CI, 1.8–3.8]; P < 0.001), and
  • PTX-3 (OR, 13.6 [95% CI, 6.4–28.9]; P < 0.001)
    • were associated with higher SYNTAX scores,
  • HT (OR, 0.44 [95% CI, 0.24–0.80]; P = 0.008) and
  • DM (OR, 0.48 [95% CI, 0.25–0.91]; P = 0.02)
    • were associated with lower SYNTAX scores.

In the multivariate analysis – age, DM, LDL-C, hs-CRP, and PTX-3 – were found to be

  • independent predictors of “intermediate to high” SYNTAX score (Table 4).

Increased

  • age (OR, 2.5 [95% CI, 1.3–4.8]; P = 0.007),
  • LDL-C (OR, 2.8 [95% CI, 1.5–5.2]; P = 0.001),
  • hs-CRP (OR, 3.3 [95% CI, 1.8–6.1]; P < 0.001), and
  • PTX-3 (OR, 35.4 [95% CI, 10.1–123.6]; P < 0.001)
    • were associated with increased SYNTAX scores,

whereas DM (OR, 0.08 [95% CI, 0.02–0.33]; P < 0.001) was associated with lower SYNTAX score (Table 4).

In the second univariate and multivariate analyses (where SYNTAX cutoff was 33),

  • the parameters that showed significance in the univariate analysis were age, LDL-C, glucose, hs-CRP, and PTX-3.
  • In the univariate analysis, increased
    • age (OR, 1.5 [95% CI, 1.0–2.3]; P = 0.05),
    • LDL-C (OR, 1.5 [95% CI, 0.97–2.2]; P = 0.07),
    • hs-CRP (OR, 1.4 [95% CI, 0.97–2.1]; P = 0.072), and
    • PTX-3 (OR, 18.5 [95% CI, 6.6–51.8]; P < 0.001)
      • were found to be associated with increased SYNTAX scores.

When these parameters were evaluated with multivariate analysis, only PTX-3 (OR, 18.4 [95% CI, 6.2–54.2]; P < 0.001)

    • was found to be an independent predictor for high SYNTAX score (Table 4).

Table 4   http://images.journals.lww.com/jinvestigativemed/Original.00042871-201302000-00007.TT4.jpeg

The ROC curve analysis further revealed that the PTX-3 level was a strong indicator of high SYNTAX score with

  • an area under the curve (AUC) of 0.91 (95% CI, 0.86–0.96) (Fig. 2).

The optimal cutoff of PTX-3 for the high SYNTAX score was 0.75 ng/mL.
Sensitivity, specificity, positive predictive value, and negative predictive value to identify high SYNTAX score for the PTX-3 level

  • were 90%, 84%, 97%, and 60%, respectively.
  • the ROC curve analysis of PTX-3 for intermediate-high SYNTAX score revealed that the AUC value was 0.82 (95% CI, 0.75–0.89).

The optimal threshold of PTX-3 level that

  • maximized the combined specificity and sensitivity to predict
    • intermediate to high SYNTAX score was 0.73 ng/mL.

For the cutoff value of 0.73 ng/mL, sensitivity, specificity, positive predictive value, and negative predictive value

  • to identify intermediate-high SYNTAX score were 56%, 98%, 97%, and 56%, respectively.

Figure 2   http://images.journals.lww.com/jinvestigativemed/Original.00042871-201302000-00007.FF2.jpeg

In the ROC analysis of hs-CRP for high SYNTAX scores, the AUC value was found to be 0.68 (95% CI, 0.59–0.77; P < 0.001).
The optimal threshold of hs-CRP that maximized the combined specificity and sensitivity to predict for high SYNTAX scores was 0.89 mg/dL.
Similarly, the ROC analysis of hs-CRP for the intermediate-high SYNTAX scores revealed an AUC of 0.74 (95% CI, 0.65–0.83; P = 0.001).
The cutoff value of hs-CRP to predict the intermediate-high SYNTAX scores with a maximized sensitivity and specificity was 0.66 mg/dL.
DISCUSSION
In this particular study, we investigated the relationship between the serum PTX-3 level and the severity of CAD

  • assessed by SYNTAX and Gensini scores in patients with SAP.

The PTX-3, was significantly higher than control group in the patients with CAD, and the serum PTX-3 levels

  • were associated with the SYNTAX and Gensini scores.

When compared with the hs-CRP, the PTX-3 was found to be more tightly associated with the complexity and severity of CAD in the patients with SAP.
Pentraxin 3, an acute-phase reactant that is functionally and structurally similar to CRP,1 is produced both by different kinds of cells such as

  • macrophages, dendritic cells, neutrophils, fibroblasts, and vascular endothelial cells.2
  • Pentraxin 3 is released following the inflammatory stimuli19; therefore, it may reflect the local inflammatory status in tissues.20

Serum PTX-3 levels were shown to be elevated in patients with

  • vasculitis,6 acute myocardial infarction,7,8 and systemic inflammation or sepsis,9 psoriasis, unstable angina pectoris, and heart failure.10–13

Higher PTX3 levels were reported to be associated with worse cardiovascular outcomes

  1. after acute coronary syndromes,8,21
  2. in the elderly people without known cardiovascular disease22 and
  3. associated with overall mortality in patients with stable coronary disease,
  4. independent of systemic inflammation.14

There are 2 reports investigating the association of PTX-3 level and the atherosclerotic burden.15,16 In one of these reports,

  • Knoflach et al.15 took B-mode ultrasonography as the atherosclerosis index.

They did not provide any information about coronary anatomy, and in the other report, Soeki et al.16 evaluated 40 patients who

  • underwent coronary angiography and measured their Gensini scores.

However, in none of the studies were the SYNTAX score and Gensini score used together to assess the degree of coronary atherosclerotic burden.
To our knowledge, this is the first report that showed the association of PTX-3 levels with the complexity and severity of CAD assessed by

  • SYNTAX and Gensini scores in patients with stable coronary disease.

Chronic low-grade inflammation has been thought to play a major role in the pathogenesis of atherosclerosis.23,24 Previous studies have reported that

  • levels of inflammatory markers such as hs-CRP, interleukin 6, and so on were increased in atherosclerosis.25

In the present study, both the SYNTAX and the Gensini scores were found to be correlated with serum PTX-3 and hs-CRP levels,

  • which in turn might reflect the degree of inflammation.

The SYNTAX score is an important tool in the classification of complex CAD26 and can give predictive information about short- and long-term outcomes

  • in patients with stable CAD who undergo percutaneous coronary intervention.27–30

Although the SYNTAX score is currently used for assessing the angiographic complexity of CAD rather than the severity of coronary atherosclerotic burden,

  • because more complex lesions tend to have more atherosclerotic burden,
  • the SYNTAX scores may also reflect the severity of coronary atherosclerotic burden.

The Gensini score, a well-known and widely used scoring system to evaluate the severity of CAD,18 was measured and

  • found to be well correlated with the SYNTAX score,
    • which supports the idea that angiographically more complex lesions tend to have more atherosclerotic burden.

When compared with the hs-CRP,

  • the PTX-3 seems to be more tightly associated with coronary disease burden (r = 0.36 vs r = 0.87).

We found out that the serum PTX-3 levels were higher than those in the control group, even in the low SYNTAX group.
On the other side, the serum hs-CRP levels were not different in the control and the low SYNTAX groups.
It was reported that the leukocytes mainly found in the coronary artery lumen are the neutrophils.31
It is also known that PTX-3 is stored in specific granules of neutrophils and released in response to inflammatory signals.32
The reason why serum PTX-3 levels seem more tightly associated with the coronary disease burden

  • when compared with serum hs-CRP levels may be the association of the
  • on-site presence of neutrophils and local inflammatory signal–triggered release of  PTX-3.

On the other hand, some human studies revealed that PTX-3 was produced more in areas of atherosclerosis and may contribute to its pathogenesis.31
Some other studies suggested that PTX-3 may be part of a protective mechanism in

  • vascular repair via inhibiting fibroblast growth factor 2 or some other growth factors responsible for smooth muscle proliferation.33,34

But still, the exact role of PTX-3 in the pathophysiology of atherosclerosis seems to be obscure for the time being. It is well established that atherosclerosis
has an inflammatory background in most of the cases. In addition to that, high blood CRP level is known as an indicator of future cardiovascular disease risk
even in healthy individuals.35 According to the results of univariate and multivariate analyses, for intermediate and high SYNTAX scores,

  1. age, DM, LDL-C, hs-CRP, and PTX-3 were found to be independent predictors, whereas for the presence of
  2. high SYNTAX score, only PTX-3 was found to be an independent predictor.

Because of the tighter association with atherosclerotic burden and the on-site vascular presence,

    • PTX-3 may be a promising candidate marker for vascular inflammation and future cardiovascular events.

LIMITATIONS
The major limitation of the current study is the number of patients included. It would be better to include more patients to increase the statistical power.

Besides, the SYNTAX and Gensini scores give us an idea about the complexity and severity of coronary atherosclerosis; however,
with coronary angiography alone, it is not possible to understand the extent of coronary plaque. In addition to that, the coronary anatomy of the
control group was not known, which was another limitation. Our selected population was free of other confounders of systemic inflammation, and
we did not have data about inflammatory markers other than hs-CRP, such as interleukin 6, tumor necrosis factor α, and so on, which may be accepted
as a limitation. Another limitation of the current study is that because there was no long-term follow-up of the patients, it did not provide any prognostic
data in terms of future cardiovascular events.
CONCLUSIONS
Pentraxin 3, a novel inflammatory marker, is associated with the complexity and severity of the CAD assessed by the SYNTAX and the Gensini scores in patients with SAP and seems to be more tightly associated with coronary atherosclerotic burden than hs-CRP.

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Keywords:  pentraxin 3; coronary artery disease; SYNTAX score; hs-CRP; inflammation

This is not the only recent finding that adds to the ability to evaluate these patients.  An as yet unpublished paper, expected to be published soon reports on

QRS fragmentation as a Prognostic test in Acute Coronary Syndrome,  and this reviewer expects the work to have a high impact.  The authors state that
QRS complex fragmentation is a promising bed-side test for assessment of prognosis in those patients.  Presence of fragmented QRS in surface ECG during ACS

  • represents myocardial scar or fibrosis and reflect severity of coronary lesions and a correlation between fQRS and depression of Lv function is established.

There are still other indicators that need to be considered, such as the mean arterial blood pressure.

There has been review and revisions of the guidelines for treatment of UA/NSTEMI within the last year, with differences being resolved among the Europeans and US.

Guidelines Updated for Unstable Angina/Non-ST Elevation Myocardial Infarction
According to the current study by Jneid and colleagues, new evidence is available on the management of unstable angina. This report replaces the 2007 American College of Cardiology Foundation/American Heart Association (ACC/AHA) Guidelines for the Management of Patients With Unstable Angina/Non–ST-Elevation Myocardial Infarction (UA/NSTEMI) that were updated by the 2011 guidelines.

This guideline was reviewed by

  • 2 official reviewers each nominated by the ACCF and the AHA, as well as
  • 1 or 2 reviewers each from the American College of Emergency Physicians; the Society for Cardiovascular Angiography and Interventions; and the Society of Thoracic Surgeons; and
  • 29 individual content reviewers, including members of the ACCF Interventional Scientific Council.

The recommendations in this focused update are considered current

  • until they are superseded in another focused update or the full-text guideline is revised, and are official policy of both the ACCF and the AHA.

STUDY SYNOPSIS AND PERSPECTIVE
American cardiology societies have caught up with the European Society of Cardiology by

  • issuing their second update to the UA/NSTEMI guidelines in 18 months,
  • with the 2012 focused update replacing the 2011 guidelines [1].

The new recommendations include ticagrelor (Brilinta) as one of the options for antiplatelet therapy alongside prasugrel (Effient) and clopidogrel, bringing them in line with European.
The European guidance, however, gave precedence to the new antiplatelets over clopidogrel, whereas the American update “places ticagrelor on an equal footing with the other two antiplatelets available
this is the main reason for the update,” lead author Dr Hani Jneid (Baylor College of Medicine, Houston, TX), told heartwire . “Doctors now have a choice for second-line therapy after aspirin, depending on

  • the patient’s clinical scenario,
  • physician preference, and cost,”
    • now that clopidogrel is available generically.

The US decision to recommend

  • first prasugrel–in its 2011 update to the UA/NSTEMI guidelines–and
  • now ticagrelor as equivalent antiplatelet therapy choices to clopidogrel after aspirin
    • puts it somewhat at odds with the Europeans,
    • who reserve clopidogrel use for those who cannot take the newer agents.

The reason for the Americans differing stance is that because while they are faster acting and more potent–

  • the cost-effectiveness of the new agents is not known.
  • it isn’t clear how the efficacy observed in pivotal clinical trials of these agents is going to translate into real-world benefit,
  • and issues such as bleeding with prasugrel and compliance with a twice-daily drug such as ticagrelor remain concerns.

Bulk of 2012 Update on How to Use Ticagrelor
The 2012 ACCF/AHA focused update for the management of UA/NSTEMI stresses that

  • all patients at medium/high risk should receive dual antiplatelet therapy on admission,
  • with aspirin being first-line, indefinite therapy.

The bulk of the update centers on how to use ticagrelor which–

  • like prasugrel or clopidogrel–
  • can be added to aspirin for up to 12 months (or longer, at the discretion of the treating clinician).

Jneid notes it’s important to remember that prasugrel can only be used in the cath lab

  • in patients undergoing percutaneous coronary intervention (PCI),
  • whereas ticagrelor, like clopidogrel, can be used in medically managed or PCI patients.

And he emphasizes that, in line with the FDA’s black-box warning on ticagrelor,

The 81-mg aspirin dose is also considered a reasonable option in preference to a higher maintenance dose of 325 mg in

  • any acute coronary syndrome (ACS) patient following PCI, he adds, as
  • this strategy is believed to result in equal efficacy and lower bleeding risk.

With regard to how long antiplatelet therapy should be stopped before planned cardiac surgery, the recommendation is

  • five days for ticagrelor–the same as that advised for clopidogrel.
  • and seven days prior to surgery for prasugrel.

Jneid also highlights other important recommendations from the 2011 focused update carried over to 2012:

It is “reasonable” to proceed with cardiac catheterization and revascularization within

  • 12–24 hours of admission in initially stable, very high-risk patients with ACS.

An invasive strategy is “reasonable” in patients with

  • mild and moderate chronic kidney disease.

In those with diabetes hospitalized with ACS, insulin use should target glucose levels <180 mg/dL,

  • a less-intensive reduction than previously recommended.

Platelet function or genotype testing for clopidogrel resistance are both considered “reasonable”

  • if clinicians think the results will alter management,
  • but Jneid acknowledged that “there is not much evidence to support these assays” .

Committee Encourages Participation in Registries
Jneid observes that unstable angina and NSTEMI are “very common” conditions that carry a high risk of death and recurrent heart attacks,

  • which is why “the AHA and ACCF constantly update their guidelines so that physicians can provide patients with
  • the most appropriate, aggressive therapy with the goal of improving health and survival.”

To this end, he notes that the writing panel encourages

  • clinicians and hospitals to participate in quality-of-care registries designed
  • to track and measure outcomes, complications, and
  • adherence to evidence-based medicines.

Conflicts of interest for the writing committee are listed in the paper.

References

Jneid H, Anderson JL, Wright SR, et al. 2012 ACCF/AHA focused update on the guideline for the management of patients with unstable angina/non-ST elevation myocardial infarction (Updating the 2007 guideline and replacing the 2011 focused update): A report of the ACCF/AHA.
Circulation 2012;      Available at: http://circ.ahajournals.org/  http://dx.doi.org/10.1161/CIR0b013e3182566fleo
source   http://www.medscape.org

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Age-standardised disability-adjusted life year...

Age-standardised disability-adjusted life year (DALY) rates from Cardiovascular diseases by country (per 100,000 inhabitants). (Photo credit: Wikipedia)

English: Cardiovascular disease: PAD therapy w...

English: Cardiovascular disease: PAD therapy with stenting Deutsch: PAVK Therapie: Kathetertherapie mit stenting (Photo credit: Wikipedia)

Micrograph of an artery that supplies the hear...

Micrograph of an artery that supplies the heart with significant atherosclerosis and marked luminal narrowing. Tissue has been stained using Masson’s trichrome. (Photo credit: Wikipedia)

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AMPK Is a Negative Regulator of the Warburg Effect and Suppresses Tumor Growth In Vivo

Reporter-Curator: Stephen J. Williams, Ph.D.

AMPK Is a Negative Regulator of the Warburg Effect and Suppresses Tumor Growth In Vivo

Word Cloud by Daniel Menzin

There has been a causal link between alterations in cellular metabolism and the cancer phenotype.  Reorganization of cellular metabolism, marked by a shift from oxidative phosphorylation to aerobic glycolysis for cellular energy requirements (Warburg effect), is considered a hallmark of the transformed cell.  In addition, if tumors are to survive and grow, cancer cells need to adapt to environments high in metabolic stress and to avoid programmed cell death (apoptosis). Recently, a link between cancer growth and metabolism has been supported by the discovery that the LKB1/AMPK signaling pathway as a tumor suppressor axis[1].

LKB1/AMPK/mTOR Signaling Pathway

The Liver Kinase B1 (LKB1)/AMPK  AMP-activated protein kinase/mammalian Target of Rapamycin Complex 1 (mTORC1) signaling pathway links cellular metabolism and energy status to pathways involved in cell growth, proliferation, adaption to energy stress, and autophagy.  LKB1 is a master control for 14 other kinases including AMPK, a serine-threonine kinase which senses cellular AMP/ATP ratios.  In response to cellular starvation, AMPK is allosterically activated by AMP, leading to activation of ATP-generating pathways like fatty acid oxidation and blocking anabolic pathways, like lipid and cholesterol synthesis (which consume ATP).  In addition, AMPK regulates cell growth, proliferation, and autophagy by regulating the mTOR pathway.  AMPK activates the tuberous sclerosis complex 1/2, which ultimately inhibits mTORC1 activity and inhibits protein translation.  This mTOR activity is dis-regulated in many cancers.

LKB1AMPK pathway

LKB1/AMPK in Cancer

  • Somatic mutations of the STK11 gene encoding LKB1 are detected in lung and cervical cancers
  • Therefore LKB1 may be a strong tumor suppressor
  • Pharmacologic activation of LKB1/AMPK with metformin can suppress cancer cell growth

In a recent Cell Metabolism paper[2], Brandon Faubert and colleagues describe how AMPK activity reduces aerobic glycolysis and tumor proliferation while loss of AMPK activity promotes tumor proliferation by shifting cells to aerobic glycolysis and increasing anabolic pathways in a HIF1-dependent manner.

The paper’s major findings were as follows:

  • Loss of AMPKα1 cooperates with the Myc oncogene to accelerate lymphomagenesis
  • AMPKα dysfunction enhances aerobic glycolysis (Warburg effect)
  • Inhibiting HIF-1α reverses the metabolic effects of AMPKα loss
  • HIF-1α mediates the growth advantage of tumors with reduced AMPK signaling

Summary

AMPK is a metabolic sensor that helps maintain cellular energy homeostasis. Despite evidence linking AMPK with tumor suppressor functions, the role of AMPK in tumorigenesis and tumor metabolism is unknown. Here we show that AMPK negatively regulates aerobic glycolysis (the Warburg effect) in cancer cells and suppresses tumor growth in vivo. Genetic ablation of the α1 catalytic subunit of AMPK accelerates Myc-induced lymphomagenesis. Inactivation of AMPKα in both transformed and nontransformed cells promotes a metabolic shift to aerobic glycolysis, increased allocation of glucose carbon into lipids, and biomass accumulation. These metabolic effects require normoxic stabilization of the hypoxia-inducible factor-1α (HIF-1α), as silencing HIF-1α reverses the shift to aerobic glycolysis and the biosynthetic and proliferative advantages conferred by reduced AMPKα signaling. Together our findings suggest that AMPK activity opposes tumor development and that its loss fosters tumor progression in part by regulating cellular metabolic pathways that support cell growth and proliferation.

Below is the graphical abstract of this paper.

Graphical Abstract FINAL.pptx

(Photo credit reference(2; Faubert et. al) permission from Elsevier)

However, this regulation of tumor promotion by AMPK may be more complicated and dependent on the cellular environment.

Nissam Hay from the University of Illinois College of Medicine, Chicago, Illinois, USA and his co-workers Sang-Min Jeon and Navdeep Chandel were investigating the mechanism through which LKB1/AMPK regulate the balance between cancer cell growth and apoptosis under energy stress[3]. In their system, the loss of function of either of these proteins makes cells more sensitive to apoptosis in low glucose environments, and cells deficient in either AMPK or LKB1 were shown to be resistant to oncogenic transformation.  Whereas previous studies showed (as above) AMPK opposes tumor proliferation in a HIF1-dependent manner, their results showed AMPK could promote tumor cell survival during periods of low glucose or altered redox status.

The researchers incubated LKB1-deficient cancer cells in the presence of either glucose or one of the non-metabolizable glucose analogues 2-deoxyglucose (2DG) and 5-thioglucose (5TG), and found that 2DG, but not 5TG, induced the activation of AMPK and protected the cells from apoptosis, even in cells that were deficient in LKB1.

The authors demonstrated that glucose deprivation depleted NADPH levels, increased H2O2 levels and increased cell death, and that this was accelerated in cells deficient in the enzyme glucose-6-phosphate dehydrogenase. Anti-oxidants were also found to inhibit cell death in cells deficient in either AMPK or LKB1.

Knockdown or knockout of either LKB1 or AMPK in cancer cells significantly increased levels of H2O2 but not of peroxide (O2) during glucose depletion. The glucose analogue 2DG was able to activate AMPK and maintain high levels of NADPH and low levels of H2O2 in these cells.

The nucleotide coenzyme NADPH is generated in the pentose phosphate pathway and mitochondrial metabolism, and consumed in H2O2 elimination and fatty acid synthesis. If glucose is limited mitochondrial metabolism becomes the major source of NADPH, supported by fatty acid oxidation. AMPK is known to be a regulator of fatty acid metabolism through inhibition of two acetyl-CoA carboxylases, ACC1 and ACC2.

Short interfering RNAs (siRNAs) to knock down levels of both ACC1 and ACC2 in A549 cancer cells and found that only ACC2 knockdown significantly increased peroxide accumulation and apoptosis, while over-expression of mutant ACC1 and ACC2 in LKB1-proficient cells increased H2O2 and apoptosis.

Therefore, it was concluded AMPK acts to promote early tumor growth and prevent apoptosis in conditions of energy stress through inhibiting acetyl-CoA carboxylase activity, thus maintaining NADPH levels and preventing the build-up of peroxide in glucose-deficient conditions.

This may appear to be conflicting with the previous report in this post however, it is possible that these reports reflect differences in the way cells respond to various cellular stresses, be it hypoxia, glucose deprivation, or changes in redox status.  Therefore a complex situation may arise:

  • AMPK promotes tumor progression under glucose starvation
  • AMPK can oppose tumor proliferation under a normoxic, HIF1-dependent manner
  • Could AMPK regulation be different in cancer stem cells vs. non-stem cell?

References:

1.            Green AS, Chapuis N, Lacombe C, Mayeux P, Bouscary D, Tamburini J: LKB1/AMPK/mTOR signaling pathway in hematological malignancies: from metabolism to cancer cell biology. Cell Cycle 2011, 10(13):2115-2120.

2.            Faubert B, Boily G, Izreig S, Griss T, Samborska B, Dong Z, Dupuy F, Chambers C, Fuerth BJ, Viollet B et al: AMPK is a negative regulator of the Warburg effect and suppresses tumor growth in vivo. Cell metabolism 2013, 17(1):113-124.

3.            Jeon SM, Chandel NS, Hay N: AMPK regulates NADPH homeostasis to promote tumour cell survival during energy stress. Nature 2012, 485(7400):661-665.

 Other posts on this site related to Warburg Effect and Cancer include:

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Melatonin and its effect on acetylcholinesterase activity in erythrocytes

Author: S. Chakravarty, PhD

 

Objective: The study was conducted to see the effect of melatonin on the activity of acetylcholinesterase in red blood cells.

Mammalian red blood cells contain membrane-bound acetylcholinesterase which acts as biomarkers of oxidative imbalance. Melatonin is a powerful free radical scavenger and upregulates several antioxidant enzymes to reduce oxidative stress. Being an effective antioxidant, it may initiate variation in erythrocyte acetylcholinesterase activity.

The study was carried out on twenty-nine subjects of both sexes who gave their informed consent for the use of their blood samples for the study (Chakravarty and Rizvi, 2011a). The red cells isolated from blood collected at two different timings of the day, viz., 10:00 a.m. and 10:00 p.m.,were subjected to in vitro treatment with melatonin in a dose-dependant manner followed by the assay of enzyme activity (Ellman et al., 1961).

Acetylcholinesterase (AChE) is also found on the red blood cell membranes, where it constitutes the Yt blood group of antigen, which is a blood-group determining protein. AChE has the features of a secreted rather than a transmembrane protein because it lacks long hydrophobic stretches, other than that which forms the signal peptide (Li et al., 1991). Besides, acetylcholinesterase activity in erythrocytes may be considered as a marker of central cholinergic status (Kaizer et al., 2008). AChE shows highest activity in the immature rat brain is at 6.00 a.m. and lowest after midnight, which undergoes a reversal after attaining maturity (Moudgil and Kanungo, 1973). The enzyme also exhibits annual changes in its activity (Lewandowski, 2008). Acetylcholinesterase activity has been used to for studying the activity pattern of human erythrocytes (Prall et al., 1998). Free radicals and increased oxidative stress have been found to reduce AChE activity (Molochkina et al., 2005). This indicates that melatonin may have some relation with the circadian rhythmicity of acetylcholinesterase activity.

The concentration-dependant assay of AChE activity in red cells bear close relation with the circadian rhythm in humans thus sharing a similar conclusion with that mentioned by Moudgil and Kanungo (Moudgil and Kanungo, 1973). The effect of melatonin on enzyme functions in erythrocytes follows rhythmic modulation with day/night cycle. The samples obtained in the morning exhibit significantly higher activity of acetylcholinesterase than those obtained during the night-time. The samples collected at two different timings of the day show different response to in vitro melatonin treatment. The rise in AChE activity is more pronounced at low doses of melatonin. Our results indicate significant increase in acetylcholinesterase activity in diurnal as well as nocturnal blood samples at different concentrations of exogenous melatonin (Rizvi and Chakravarty, 2011). At supraphysiological doses, the enzyme activity exhibits no significant change, owing to the prooxidative influence exerted by melatonin (Marchiafava and Longoni, 1999).

Acetylcholinesterase activity is affected by the hydrophobic environment of the cell membrane and depends on the plasma membrane fluidity and surface charge of the cell (Klajnert et al., 2004).  The activity of AChE depends largely on the biophysical features of membrane. Oxidative stress decreases the fluidity of membrane lipid bilayer, thus affecting its normal functions (Goi et al., 2005).  Such are the ill-effects of oxidative radicals that tend to increase with aging. The decrease in AChE correlates significantly with age-induced oxidative stress (Jha and Rizvi, 2009).  On the basis of our study we conclude that melatonin modulates acetylcholinesterase activity in erythrocytes. The rhythmicity observed in the activity of acetylcholinesterase in response to the melatonin confirms our opinion on the relationship between the enzyme function, pineal secretion and pharmacological dosage of the indole antioxidant.

References:

  1. Chakravarty S, Rizvi SI, Circadian modulation of sodium-potassium ATPase and sodium-proton exchanger in human erythrocytes: in vitro effect of melatonin. <a href=”80-6. “http://www.ncbi.nlm.nih.gov/pubmed/21366966
  2. Ellman GL, Courtney KD,      Andres Jr V, Featherstone RM, A new and rapid colorimeteric determination of acetylcholinesterase activity. Biochem Pharmacol 1961; 7(2): 88–95.
  3. Goi G, Cazzola R,      Tringali C, Massaccesi L, Volpe SR, Rondanelli M, Ferrari      E, Herrera      CJ, Cestaro      B, Lombardo      A, Venerando      B, Erythrocyte membrane alterations during      ageing affect beta-D-glucuronidase and neutral sialidase in elderly      healthy subjects. Exp Gerontol 2005; 40(3): 219-25.
  4. http://www.ncbi.nlm.nih.gov/pubmed/?term=alterations+during++++++ageing+affect+beta-D-glucuronidase+and+neutral+sialidase+in+elderly++++++healthy+subjects.
  5. Jha R, Rizvi SI, Age-dependant  decline in erythrocyte acetylcholinesterase activity: correlation with oxidative stress. Biomed Pap Med Fac Univ Palacky Olomouc Czech Repub 2009; 153(3):195–8.
  6. http://www.ncbi.nlm.nih.gov/pubmed/19851431
  7. Kaizer RR, Correa MC, Gris LR, Da Rosa CS, Bohrer D, Morsch VM, Schetinger MR, Effect of long-term exposure to aluminum on the acetylcholinesterase activity in the central nervous system and erythrocytes. Neurochem Res 2008; 33(11):2294-301.
  8. http://www.ncbi.nlm.nih.gov/pubmed/?term=Effect+of+long-term+exposure+to+aluminum+on+the+acetylcholinesterase+activity+in+the+central+nervous+system+and+erythrocytes.
  9. Klajnert B, Sadowska M,      Bryszewska M, The effect of polyamidoamine dendrimers on human erythrocyte membrane acetylcholinesterase activity. Bioelectrochem 2004; 65(1): 23-6.
  10. http://www.ncbi.nlm.nih.gov/pubmed/?term=The+effect+of+polyamidoamine+dendrimers+on+human+erythrocyte+membrane+acetylcholinesterase+activity.
  11. Lewandowski MH, Annual changes of circadian acetylcholinesterase activity in the brain stem compared to locomotor activity of the mouse under LD 12/12. J Interdisiplinary Cycle Res 1990; 21 (1): 25-32.
  12. http://www.tandfonline.com/doi/abs/10.1080/09291019009360023?journalCode=nbrr19
  13. Li Y, Camp      S, Rachinsky TL, Getman D, Taylor P, Gene structure of mammalian acetylcholinesterase. Alternative exons dictate tissue-specific expression. J Biol Chem 1991; 266(34): 23083–90.
  14. http://www.ncbi.nlm.nih.gov/pubmed/?term=Gene+structure+of+mammalian+acetylcholinesterase.+Alternative+exons+dictate+tissue-specific+expression
  15. Marchiafava PL, Longoni B, Melatonin as an antioxidant in retinal photoreceptors. J Pineal Res 1999; 26(3): 184-89.
  16. http://www.ncbi.nlm.nih.gov/pubmed/10231733
  17. Molochkina EM, Zorina OM, Fatkullina LD, Goloschapov AN, Burlakova EB, H2O2 modifies membrane structure and activity of acetylcholinesterase. Chem Biol Interact 2005; 157-158(1): 401-4.
  18. http://www.ncbi.nlm.nih.gov/pubmed/?term=H2O2+modifies+membrane+structure+and+activity+of+acetylcholinesterase.
  19. Moudgil VK, Kanungo MS, Effect of age on the circadian rhythm of acetylcholinesterase of the brain of the rat. Comp Gen Pharmacol 1973; 4(14):127-30.
  20. http://www.ncbi.nlm.nih.gov/pubmed/4770270
  21. Prall YG, Gambhir KK, Ampy FR, Acetylcholinesterase: an enzymatic marker of human red blood cell aging. Life Sci 1998; 63(3): 177-84.
  22. http://www.ncbi.nlm.nih.gov/pubmed/?term=Acetylcholinesterase%3A+an+enzymatic+marker+of+human+red+blood+cell+aging
  23. Rizvi SI, Chakravarty S, Modulation of acetylcholiesterase activity by melatonin in red blood cells. Acta Endocrinologica (Buc), 2011; 8(3): 311-16..

 

 

 

 

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Progression in Bronchial Dysplasia

Curator and Reporter: Larry H Bernstein, MD, FCAP

 

Genomic evidence of pre-invasive clonal expansion, dispersal and progression in bronchial dysplasia

F McCaughan, CP Pipinikas, SM Janes, PJ George, PH Rabbitts and PH Dear
MRC Laboratory of Molecular Biology, Cambridge, Centre for Respiratory Research, Royal Free and University College Medical School, London, University College London Hospitals, London, Leeds Institute of Molecular Medicine, St James’s University Hospital, Leeds, UK
J Pathol 2011; 224: 153–159   http://dx.doi.org/10.1002/path.2887
http://www.jpathol.com/Genomic evidence of pre-invasive clonal expansion, dispersal and progression in bronchial dysplasia
http://www.ncbi.nlm.nih.gov/pubmed/21506132
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3378694/

The term ‘field cancerization’ is used to describe an epithelial surface that has a propensity to develop cancerous lesions, and in the case of the

  • aerodigestive tract this is often as a result of chronic exposure to carcinogens in cigarette smoke.

The clinical endpoint is the development of multiple tumours,

  • either simultaneously or sequentially in the same epithelial surface.

The mechanisms underlying this process remain unclear; one possible explanation is that

  • the epithelium is colonized by a clonal population of cells that are at increased risk of progression to cancer.

We now address this possibility in a short case series, using individual genomic events as molecular biomarkers of clonality. In squamous lung cancer the most common genomic aberration is 3q amplification. We use a digital PCR technique to

  • assess the clonal relationships between
  • multiple biopsies in a longitudinal bronchoscopic study,
  • using amplicon boundaries as markers of clonality.

We demonstrate that clonality can readily be defined by these analyses and confirm that

  • field cancerization occurs at a pre-invasive stage and that
  • pre-invasive lesions and
  • subsequent cancers are clonally related.

We show that while the amplicon boundaries can be shared between different biopsies,

the degree of 3q amplification and the internal structure of the 3q amplicon varies from lesion to lesion. Finally, in this small cohort, the degree of 3q amplification corresponds to clinical progression.
Keywords: clonality; bronchial dysplasia; molecular copy-number counting
Conflict of interest: A patent for molecular copy-number counting has been applied for by the UK Medical Research Council. Paul Dear is named on the patent application..

The term ‘field cancerization’ was first coined many years ago and the potential underlying biological processes have been studied and discussed at length,

  • particularly in cancers of the aerodigestive tract .

Three possible mechanisms for field cancerization have been mooted in lung cancer.

  • an epithelial surface exposed to repeated insult, such as cigarette carcinogens,
    • could develop multiple separate dysplastic foci that
    • do not originate from a single clone but share similar genetic aberrations
      • as a result of the common carcinogenic insult.
    • In time, one or more of these foci may progress to cancer.
  • a mutant clone expands and migrates to colonize the epithelial surface,
    • without breaching the basement membrane, and
    • molecular divergence results in subclonal populations that may or may not progress.
  • In the third explanation an established cancer spreads to form multifocal clonal tumours.

In the past shared mutations (particularly of TP53 ) or patterns of loss of heterozygosity (LOH) have been the main biomarkers used

  • to infer the presence or absence of a clonal relationship between separate biopsies
  • from a single individual in lung cancer and pre-invasive bronchial dysplasia.

It could be argued that defining a specific shared mutation in TP53,

  • a gene with multiple different mutational hotspots,
  • with or without supportive LOH studies,
  • is more suggestive of clonality than LOH patterns alone.

multiple, anatomically distinct biopsies from an individual with widespread mild dysplasia

  • had a common mutation in TP53,
    • indicating epithelial colonization at a pre-invasive stage.

recently – 70 multifocal lung cancers from 30 individuals suggested,

  • on the basis of both LOH and TP53 mutational analysis,
  • in 77% of individuals the lesions were clonally related.

a digital PCR technique, microdissection molecular copy-number counting (μMCC), can provide detailed high-resolution information on

  • structural genomic events
  • in archived pre-invasive bronchial biopsies, in which
    • the amount of available tissue for analysis is significantly limited and the DNA is of poor quality.

We used this approach to show that 3q amplification is consistently observed in high-grade, but

  • not low-grade, bronchial dysplastic lesions, and that
  • the likely focus of this amplification is SOX2,
    • consistent with recent results from other groups.

This study was prompted by an observation that at very low resolution (2 Mb)

  • a high-grade lesion and
  • a subsequent cancer appeared to share amplicon boundaries.

Therefore, these reasearchers used ultra high-resolution analysis of

  • shared amplicon boundaries
  • to define clonal relationships between
  • microdissected biopsies taken from
  • anatomically distinct parts of the bronchial tree in the same individuals.

Discussion

Field cancerization in the bronchial tree is often described, both in clinical practice and in terms of molecular biomarkers, but the mechanism and natural history of this process remains unclear.  These data, using precisely delineated amplicon boundaries as genomic biomarkers, confirm that

  • clonal expansion and dispersal of cells occurs and that
  • subclonal populations emerge with varying molecular characteristics and clinical outcomes.

A consistent observation in the current cases is that

  • the amplitude of 3q amplification predicts which lesion is likely to progress; and further,
  • there is incremental 3q amplification in those lesions that do progress.

The progression of dysplasia to invasion is generally held to reflect ongoing selection of  clonally advantageous genetic events. However, the contribution of regional genomic events to neoplastic progression is a focus of some debate—whether

  • it is of pathogenic consequence or
  • an epiphenomenon reflecting genome instability.

3q amplification may be

  • selectively neutral or it may be
  • a critical stage in the development of squamous lung cancer.

In support of the latter, the almost uniform finding of 3q amplification in invasive squamous lung cancer

  • its selection in the progression to invasion
    • points to a significant and perhaps obligate role
    • in the pathogenesis of SQC.

Whether SOX2 is the main target of this amplification or one of a number of target oncogenes that are co-amplified remains unclear.

English: Bronchial anatomy detail of alveoli a...

English: Bronchial anatomy detail of alveoli and lung circulation. Français : Anatomie pulmonaire: détail des alvéoles et de la circulation pulmonaires . (Photo credit: Wikipedia)

copy neutral LOH cancer

copy neutral LOH cancer (Photo credit: Wikipedia)

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Lp(a) Gene Variant Association

Reporter: Larry H Bernstein, MD, FCAP

 

UPDATED on 2/20/2023

Universal Testing for Lp(a): What Are We Waiting For?

Dennis R. Leahy, MD

February 01, 2023

Lp(a) was associated with atherosclerotic cardiovascular disease (ASCVD), but whether an elevated blood level was a biomarker or a causal factor proved difficult to determine.

resurgent interest in molecular pathophysiology this past decade has clarified Lp(a)’s unique contribution to atherothrombotic disease and calcific aortic stenosis.

Lp(a) comprises an apoB particle bonded to an apo(a) particle. Apo(a) is complex and has a number of isoforms that can result in large heterogenicity in apo(a) size between, as well as within, individuals. This contributes to controversy about the ideal assay and whether Lp(a) levels should be expressed as mass (mg/dL) or number of particles (nmols/L). This should not, however, deter universal testing.

Universal Lp(a) testing would spotlight this pervasive and important risk factor that was referred to as the “horrible” cholesterol in a recent review.

To date, trials of an antisense oligonucleotide and a small interfering RNA molecule targeting hepatic LPA messenger RNA have confirmed that plasma Lp(a) levels can be significantly and safely lowered. If the ongoing Lp(a) HORIZON and OCEAN(a) phase 3 trials have positive outcomes in patients with known ASCVD, this would spawn a host of clinical trials to explore the possibilities of these therapies in primary prevention as well. These will require tens of thousands of enrollees, and universal testing would expand the pool of potential participants.

Recent data from the United Kingdom suggest that attainment of specific LDL-C levels may offset the risk for vascular events in those with high Lp(a) levels.

SOURCE

https://www.medscape.com/viewarticle/987221#vp_1

LDL-Lowering to Specific Targets May Offset Risk From High Lp(a)

@@@@

Lp(a) Gene Variant Associated With Aortic Stenosis

Reported by Lisa Nainggolan Feb 06, 2013; GThanassoulis et al. NEJM http://www.theheart.org/article/1503525.do

People carrying this single nucleotide polymorphism (SNP) had a doubling of the risk of valve calcification on computer tomography (CT) compared with those without the variation. The same SNP has previously been identified as a risk factor for increased Lp(a) levels and coronary artery disease (CAD). Findings Could Reawaken Interest in Therapies Targeting Lp(a)

A Single Nucleotide Polymorphism is a change o...

A Single Nucleotide Polymorphism is a change of a nucleotide at a single base-pair location on DNA. Created using Inkscape v0.45.1. (Photo credit: Wikipedia)

 

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Phosphatidyl-5-Inositol Signaling by Pin1

 

Reporter: Larry H Bernstein, MD, FCAP

 

Regulation of Phosphatidylinositol-5-Phosphate Signaling by Pin1 Determines Sensitivity to Oxidative Stress

Willem-Jan Keune et al.
Increasing the abundance of the phospholipid PtdIns5P protects cells from oxidative stress.
Science Signaling   27 nov 2012; 5:252.
  1. T cell receptor (TCR) and costimulatory molecule mediated signaling
  2. culminate in maximal cytokine mRNA production and stability.
The transcriptional responses to co-stimulatory T cell signaling involve calcineurin and NF-AT, which
    • can be antagonized by interference with the cis-trans peptidyl-prolyl isomerases (PPIase), cyclophilin A and FKBP.
Signaling molecules downstream of CD28
    • which are essential for the stabilization of cytokine mRNAs are largely unknown.

Pin1, a third member of the PPIase family

    • mediates the post-transcriptional regulation of Th1 cytokines by activated T cells.

Blockade of Pin1 by pharmacologic or genetic means

  • greatly attenuated IFN-γ, IL-2 and CXCL-10 mRNA
    • stability,
    • accumulation and
    • protein expression after cell activation.

In vivo, Pin1 blockade prevented

  • both the acute and chronic rejection of MHC mismatched, orthotopic rat lung transplants by
  • reducing the expression of IFN-γ and CXCL-10.

Combined transcriptional and post-transcriptional blockade with

    • cyclosporine A and the Pin1 inhibitor, juglone, was synergistic.

These data suggest Pin1 inhibitors should be explored for use as immunosuppressants and employed with available calcineurin inhibitors to reduce toxicity and enhance effectiveness.
Esnault S, Braun RK, Shen Z-J, Xiang Z, Heninger E, et al. (2007)
Pin1 Modulates the Type 1 Immune Response. PLoS ONE 2(2): e226.  http://dx. doi.org/10.1371/journal.pone.0000226

Mixed-lineage kinase 3 phosphorylates prolyl-isomerase Pin1 to regulate its nuclear translocation and cellular function
Velusamy Rangasamya,1, Rajakishore Mishraa,1, Gautam Sondarvaa, Subhasis Dasa, et al.
Loyola University Chicago, Maywood, IL 60153;  Beth Israel Deaconess Medical Center, Boston, MA 02115; University of Mississippi Medical Center, Jackson, MS 39216;
University of Wisconsin, Madison, WI 53705; Hines Veterans Affairs Medical Center, Hines, IL 60141; and College of Veterinary Medicine, Iowa State University, Ames, IA 50011
Edited* by Michael Karin, University of California, San Diego School of Medicine, La Jolla, CA, and approved April 11, 2012
Nuclear protein peptidyl-prolyl isomerase Pin1-mediated prolyl isomerization is

  • an essential and novel regulatory mechanism for protein phosphorylation.

Therefore, tight regulation of Pin1 localization and catalytic activity is

  • crucial for its normal nuclear functions.

Pin1 is commonly dysregulated during oncogenesis and likely contributes to these pathologies; The mechanism by which Pin1 catalytic activity and nuclear localization are increased is unknown.
Here we demonstrate that

  1. mixed-lineage kinase 3 (MLK3), a MAP3K family member,
  2. phosphorylates Pin1 on a Ser138 site
  3. to increase its catalytic activity and nuclear translocation.
This phosphorylation event

  1. drives the cell cycle and
  2. promotes cyclin D1 stability and centrosome amplification.

Pin1 pSer138 is significantly

  • up-regulated in breast tumors and
  • is localized in the nucleus.

These findings collectively suggest that the MLK3-Pin1 signaling cascade plays a critical role

  1. in regulating the cell cycle,
  2. centrosome numbers, and
  3. oncogenesis. breast cancer

JNK Peptidyl-prolyl isomerase Pin1 plays a critical role in

  • regulating cellular homeostasis by
  • isomerizing the prolyl bond preceded by
  • a phosphorylated Ser or Thr residue (pSer/Thr-Pro) (1).

This isomerization by Pin1 regulates the biological function of several target proteins, including

  • cell-cycle regulators,
  • protooncogenes,
  • tumor suppressors, and
  • transcription factors (2).
Due to its role in controlling the cell cycle, apoptosis, growth, and stress responses, Pin1 has been linked to the pathogenesis of human diseases, including
  • cancer (3, 4),
  • asthma (5),
  • Alzheimer’s disease (AD) (6), and
  • Parkinson disease (PD) (7).

It is thus quite likely that tight regulation of Pin1 catalytic activity or expression is important for normal physiology. It is reported that Pin1 is

  • overexpressed in most types of cancer (8), whereas
  • its expression is diminished in AD brains (2).

Accumulating evidence suggests that Pin1 isomerase activity

  • and thus function are regulated by posttranslational modifications (2).

Pin1 function is also dependent on its

  • predominant nuclear localization (2),
    • consistent with its substrates being involved in transcription and cell-cycle progression.

It was recently reported that Pin1 nuclear import is regulated by a novel nuclear localization sequence in the PPIase domain, composed of basic amino acids (9). Nonetheless, the detailed mechanism that regulates Pin1 nuclear translocation is still not known. It also remains unknown whether any posttranslational modification of Pin1 can regulate its nuclear translocation or catalytic activity, and therefore directly affect its function.

Stereospecific gating of functional motions in Pin1
Andrew T. Namanjaa, Xiaodong J. Wangb, Bailing Xub, et al.
University of Notre Dame, Notre Dame, IN 46556; Virginia Tech, Blacksburg, VA 24061
Edited by Peter E. Wright, The Scripps Research Institute, La Jolla, CA, and approved June 2, 2011
Pin1 is a modular enzyme that

  • accelerates the cis-trans isomerization of phosphorylated-Ser/Thr-Pro (pS/T-P) motifs
  • found in numerous signaling proteins regulating cell growth and neuronal survival.

We have used NMR to investigate the interaction of Pin1 with three related ligands that include

  1. a pS-P substrate peptide, and
  2. two pS-P substrate analogue inhibitors
    • locked in the cis and trans conformations.

We compared the

  • ligand binding modes and
  • binding-induced changes
    • in Pin1 side-chain flexibility.

The cis and trans binding modes differ, and

  • produce different mobility in Pin1.

The cis-locked inhibitor and substrate produced a

  • loss of side-chain flexibility
    • along an internal conduit of conserved hydrophobic residues,
    • connecting the domain interface with the isomerase active site.

The trans-locked inhibitor

  • produces a weaker conduit response.

Thus, the conduit response is stereoselective. We further show

  • interactions between the peptidyl-prolyl isomerase and
  • Trp-Trp (WW) domains
    • amplify the conduit response, and
    • alter binding properties at the remote peptidyl-prolyl isomerase active site.

These results suggest that

  • specific input conformations can gate dynamic changes that support intraprotein communication.

Such gating may help control the propagation of chemical signals by Pin1, and other modular signaling proteins.

allostery ∣ protein dynamics ∣ ligand dynamics ∣ protein evolution
Phospho-serine/threonine-proline (pS/T-P) motifs are
signaling motifs within
intrinsically disordered loops of cell cycle proteins (1).
The imide bond between the pS/T and P residues can adopt

  • either the cis or trans conformation.

These conformations differ

  • in their susceptibility to kinases and phosphatases

that propagate the chemical signals governing the cell cycle.
Accordingly, the cell must regulate the cis/trans populations of these pS/T-P motifs

  • to ensure proper signal routing.

In this context, the peptidyl-prolyl isomerase Pin1 has emerged as a critical regulator (2, 3). Pin1 is a reversible enzyme that

  • catalyzes the cis-trans isomerization of the pS/T-P imide linkages (2, 3) of other signaling proteins, such as
  1. CDC25C,
  2. p53,
  3. c-Myc,
  4. NF-kB,
  5. cyclin D1, and
  6. tau (3).

Pin1 engages when external events, such as

  • S/T (de)-phosphorylation, change the cis-trans equilibrium.

Pin1 then

  1. catalyzes the cis-trans isomerization, thereby
  2. accelerating the approach to the new equilibrium (1).

Pin1 is a modular protein of 163 residues consisting of a

  • WW domain (1–39) and a larger
  • peptidyl-prolyl isomerase (PPIase) domain (50–163) (Fig. 1).

A flexible linker connects the two domains.

  1. Both domains are specific for pS/T-P motifs (1).
  2. The WW domain serves as a docking module, whereas
  3. catalysis is the sole province of the PPIase domain.

Earlier structural studies of Pin1 revealed

  1. conformational changes upon substrate interaction, thus
  2. motivating flexibility-function studies of Pin1 (4–6).
Peptidyl-prolyl Isomerase Pin1 Controls Down-regulation of Conventional Protein Kinase C Isozymes
JBC Papers in Press, Feb 8, 2012.       http://dx.doi.org/10.1074/jbc.M112.349753

H Abrahamsen, AK O’Neill, N Kannan, N Kruse¶, et al.
From the University of California, San Diego, La Jolla, California 92093
Background: Conventional PKC isozymes have a putative Pin1

  • isomerization sequence at their turn motif phosphorylation site.
Results: Pin1 binds conventional PKCs and

    • promotes their activation-induced down-regulation.
Conclusion: Pin1 isomerizes the phosphorylated turn motif of conventional PKC isozymes,

    • priming them for subsequent down-regulation.
Significance: Pin1 provides a switch regulating the lifetime of conventional PKCs. The down-regulation or cellular depletion of protein kinase C (PKC)
  • attendant to prolonged activation by phorbol esters is a
  • widely described property of this key family of signaling enzymes.

However, neither the mechanism of down-regulation nor whether this mechanism occurs following stimulation by physiological agonists is known.
**the peptidylprolyl isomerase Pin1 provides a timer for the lifetime of conventional PKC isozymes,

  • converting the enzymes into a species that can be dephosphorylated and ubiquitinated
  • following activation induced by either phorbol esters or natural agonists.

The regulation by Pin1 requires both the catalytic activity of the isomerase and the presence of a Pro immediately following the phosphorylated Thr of
the turn motif phosphorylation site,

  • one of two C-terminal sites that is phosphorylated during the maturation of PKC isozymes.
  • the second C-terminal phosphorylation site, the hydrophobic motif, docks
    • Pin1 to PKC.

Our data are consistent with a model in which Pin1

  • binds the hydrophobic motif of conventional PKC isozymes to catalyze the isomerization of the phospho-Thr-Pro peptide bond at the turn motif, thus
  • converting these PKC  isozymes into species that can be efficiently down-regulated following activation.

The peptidyl-prolyl cis-trans isomerase Pin1 is emerging as an important regulator of signal transduction pathways (1).

Pin1-catalyzed isomerization plays a key role in the control of normal cellular functions, most notably proliferation where

    • Pin1 is essential for cell cycle progression (2).

Pin1 belongs to the Parvulin family of peptidyl-prolyl cis-trans isomerases and is the only member that

  • specifically isomerizes phospho-(Ser/Thr)-Pro ((Ser(P)/Thr(P))-Pro) motifs (3):
  1. the enzyme displays an 1000-fold selectivity for peptides phosphorylated on the
  2. Ser/Thr preceding the Pro compared with unphosphorylated peptides (3).
Pin1induced conformational changes in target proteins

  • affect a variety of protein properties from
    • folding to
    • regulation of activity and stability.

As a consequence, deregulation of phosphorylation steps and their attendant conformational changes often lead to disease (4). For example, Pin1 is
downregulated in degenerating neurons from Alzheimer disease patients, correlating with age-dependent neurodegeneration (5).
Pin1 has also been implicated in cancer progression:
levels of this protein are increased in many cancers, including those of the

    • breast,
    • prostate,
    • brain,
    • lung, and
    • colon (6–9).

Thus, Pin1 has been proposed to function as a catalyst for oncogenic pathways (10). The molecular mechanisms that lead to disease progression

  • most likely involve postphosphorylation conformational changes
    • catalyzed by Pin1
    • that are required for downstream effects.
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The human immunophilin protein FKBP12 colored ...

The human immunophilin protein FKBP12 colored by hydrophobicity (white = hydrophobic) with bound FK506, an immunosuppressant used in treating organ transplant patients to prevent rejection. FKBP also has unrelated prolyl isomerase activity. (Photo credit: Wikipedia)

The human immunophilin protein FKBP12 colored ...

The human immunophilin protein FKBP12 colored by secondary structure with bound FK506, an immunosuppressant used in treating organ transplant patients to prevent rejection. FKBP also has unrelated prolyl isomerase activity. (Photo credit: Wikipedia)

 

 

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BARI 2D Trial Outcomes

Reporter: Larry H Bernstein, MD, FCAP
Results from the BARI 2D (Bypass Angioplasty Revascularization Investigation 2 Diabetes) Trial
GR. Dagenais, MD; Jiang Lu, MS; David P. Faxon, MD; Peter Bogaty, MD, et. Al.

Prognostic Impact of the Presence and Absence of Angina on Mortality and Cardiovascular Outcomes in Patients With Type 2 Diabetes and Stable Coronary Artery Disease

 

Results from the BARI 2D Trial…Bypass Angioplasty Revascularization Investigation 2 Diabetes

Objectives

The purpose of this analysis was

  1. to assess in patients with type 2 diabetes and stable coronary artery disease (CAD)
  2. whether the risk of all-cause mortality and cardiovascular events
  3. varied according to the presence or absence of angina and angina equivalent symptoms.

Background  Data on the prognostic value of symptoms in these patients are limited.

Methods

Post-hoc analysis was performed in 2,364 patients with type 2 diabetes and documented CAD enrolled in the BARI 2D (Bypass Angioplasty Revascularization Investigation 2 Diabetes) trial to determine

  1. the occurrence of death and composite of death,
  2. myocardial infarction, and
  3. stroke

during a 5-year follow-up according to cardiac symptoms at baseline.

Results

There were 1,434 patients with angina (A), 506 with angina equivalents (E), and 424 with neither of these (N).
The cumulative death rates (total 316) were

  • 12% in A,
  • 14% in E, and
  • 10% in N (p = 0.3), and

cardiovascular composite rates (total 548) were

  • 24% in A,
  • 24% in E, and
  • 21% in N (p = 0.5).

Compared with N, the hazard ratios adjusted for confounders were not different for death in

  • A (1.11; 99% CI: 0.81 to 1.53) and
  • E (1.17; 99% CI: 0.81 to 1.68) or

for cardiovascular events in

  • A (1.17; 99% CI: 0.92 to 1.50) and
  • E (1.11; 99% CI: 0.84 to 1.48).

Conclusions

Whatever their symptom status,

    • patients with type 2 diabetes and stable CAD were at similar risk of cardiovascular events and death.

These findings suggest that these patients

      • may be similarly managed in terms of risk stratification and preventive therapies.

(Bypass Angioplasty Revascularization Investigation 2 Diabetes [BARI 2D]; NCT00006305)

Key Words
  • angina;
  • coronary artery disease;
  • silent ischemia;
  • type 2 diabetes

Abbreviations and Acronyms

  • BMI, body mass index;
  • CABG, coronary artery bypass graft surgery;
  • CAD, coronary artery disease;
  • CVD,cardiovascular disease;
  • HbA1c, glycosylated hemoglobin;
  • MI, myocardial infarction;
  • PCI, percutaneous coronary intervention
Prognostic Impact of the Presence and Absence of Angina on Mortality and Cardiovascular Outcomes in Patients With Type 2 Diabetes and Stable Coronary Artery Disease
http://www.ncbi.nlm.nih.gov/pubmed/23410541

J Am Coll Cardiol. 2013 Feb 19;61(7):702-11.   http://dx. doi.org/ 10.1016/j.jacc.2012.11.036.

http://www.j.JACC.org/Prognostic Impact of the Presence and Absence of Angina on Mortality and Cardiovascular Outcomes in Patients With Type 2 Diabetes and Stable Coronary Artery Disease

Prognostic Impact of the Presence and Absence of Angina on Mortality and Cardiovascular Outcomes in Patients With Type 2 Diabetes and Stable Coronary Artery Disease: Results from the BARI 2D (Bypass Angioplasty Revascularization Investigation 2 Diabetes) Trial.
Dagenais GR, Lu J, Faxon DP, Bogaty P, Adler D, Fuentes F, Escobedo J, Krishnaswami A, Slater J, Frye RL; BARI 2D Study Group.        PMID: 23410541 [PubMed – in process]
Source: Quebec Heart and Lung University Institute, Quebec City, Quebec, Canada. Electronic address: gilles.dagenais@criucpq.ulaval.ca.

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Bildbeschreibung: Deutsch: Koronarangiografie und PTCA bei akutem Hinterwandinfarkt (li.: RCA verschlossen, re.: RCA erfolgreich dilatiert) Quelle: Deutsch: Scan von 2 Videoprints einer selbst durchgeführten Prozedur Fotograf/Zeichner: selbst gescannt / own work Datum: ca. 1999 (hochgeladen 03. Oktober 2005) andere Versionen: (Photo credit: Wikipedia)

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Lipoxin A4 Regulates Natural Killer Cell in Asthma

Reporter: Larry H Bernstein, MD, FCAP

Lipoxin A4 Regulates Natural Killer Cell and Type 2 Innate Lymphoid Cell Activation in Asthma
 C Barnig, M Cernadas, S Dutile,…BR Levy.
Sci Transl Med  27 Feb 2013. ; 5(174): p. 174ra26  SciTranslMed.             http://dx.doi.org/10.1126/scitranslmed.3004812
Asthma is a prevalent disease of chronic inflammation in which
  • endogenous counterregulatory signaling pathways are dysregulated.
Recent evidence suggests that innate lymphoid cells (ILCs), including
  • natural killer (NK) cells and
  • type 2 ILCs (ILC2s),
    • can participate in the regulation of allergic airway responses,
    • in particular airway mucosal inflammation.
Sci Transl Med 27 February 2013:  5(174) 174ra26        http://dx.doi.org/10.1126/scitranslmed.3004812
Both NK cells and ILC2s expressed
  • the pro-resolving ALX/FPR2 receptors.
Lipoxin A4, a natural pro-resolving ligand for ALX/FPR2 receptors, significantly
  • increased NK cell–mediated eosinophil apoptosis and
  • decreased IL-13 release by ILC2s.
Together, these findings indicate that ILCs are targets for lipoxin A4
  • to decrease airway inflammation and mediate the catabasis of eosinophilic inflammation

Molecular biology for formyl peptide receptors in human diseases
Yongsheng Li , 

Leukocytes accumulate at sites of inflammation and immunological reaction in response to locally existing chemotactic mediators. The first chemotactic factors structurally defined were N-formyl peptides. Subsequently, numerous ligands were identified

FPRs interact with this menagerie of structurally diverse pro- and anti-inflammatory ligands to possess important regulatory effects in multiple diseases, including

  1. inflammation,
  2. amyloidosis,
  3. Alzheimer’s disease,
  4. prion disease,
  5. acquired immunodeficiency syndrome,
  6. obesity,
  7. diabetes, and
  8. cancer.

How these receptors recognize diverse ligands and how they contribute to disease pathogenesis and host defense are basic questions currently under investigation that

    • would open up new avenues for the future management of inflammation-related diseases.

FPR2/ALX receptor expression and internalization are critical for lipoxin A4 and annexin-derived peptide-stimulated phagocytosis 
PMaderna, DC Cottell, T Toivonen, N Dufton, J Dalli, M Perretti and C Godson
The FASEB Journal Nov 2010; 24 (11): 4240-4249      Published online June 22, 2010, http://dx.doi.org/10.1096/fj.10-159913

Lipoxins (LXs) are endogenously produced eicosanoids with well-described anti-inflammatory and proresolution activities,

  • stimulating nonphlogistic phagocytosis of apoptotic cells by macrophages.

LXA4 and the glucocorticoid-derived annexin A1 peptide (Ac2–26) bind to a common G-protein-coupled receptor, termed FPR2/ALX. However, direct evidence of the involvement of FPR2/ALX in the anti-inflammatory and proresolution activity of LXA4 is still to be investigated. Here we describe FPR2/ALX trafficking in response to LXA4 and Ac2–26 stimulation. We have transfected cells with HA-tagged FPR2/ALX and studied receptor trafficking in unstimulated, LXA4 (1–10 nM)- and Ac2–26 (30 μM)-treated cells using multiple approaches that include immunofluorescent confocal microscopy, immunogold labeling of cryosections, and ELISA and investigated receptor trafficking in agonist-stimulated phagocytosis. We conclude that PKC-dependent internalization of FPR2/ALX is required for phagocytosis. Using bone marrow-derived macrophages (BMDMs) from mice in which the FPR2/ALX ortholog Fpr2 had been deleted, we observed

  • the nonredundant function for this receptor in LXA4 and Ac2–26 stimulated phagocytosis of apoptotic neutrophils.
  1. LXA4 stimulated phagocytosis 1.7-fold above basal (P<0.001) by BMDMs from wild-type mice, whereas no effect was found on BMDMs from Fpr2−/− mice.
  2. Ac2–26 stimulates phagocytosis by BMDMs from wild-type mice 1.5-fold above basal (P<0.05), but  Ac2–26 failed to stimulate phagocytosis by BMDMs isolated from Fpr2−/− mice.

These data reveal novel and complex mechanisms of the FPR2/ALX receptor trafficking and functionality in the resolution of inflammation.—
Maderna, P., Cottell, D. C., Toivonen, T., Dufton, N., Dalli, J., Perretti, M., Godson, C.
http://www.FASEB.j.org/FPR2/ALX receptor expression and internalization are critical for lipoxin A4 and annexin-derived peptide-stimulated phagocytosis.
We have transfected cells with HA-tagged FPR2/ALX and studied receptor trafficking in unstimulated, LXA4 (1–10 nM)- and Ac2–26 (30 μM)-treated cells using multiple approaches and conclude that PKC-dependent internalization of FPR2/ALX is required for phagocytosis. Using bone marrow-derived macrophages (BMDMs) from mice in which the FPR2/ALX ortholog Fpr2 had been deleted,

  • we observed the nonredundant function for this receptor in LXA4 and Ac2–26 stimulated phagocytosis of apoptotic neutrophils.

LXA4 stimulated phagocytosis 1.7-fold above basal (P<0.001) by BMDMs from wild-type mice,

  • whereas no effect was found on BMDMs from Fpr2−/− mice.

Ac2–26 stimulates phagocytosis by BMDMs from wild-type mice 1.5-fold above basal (P<0.05)

  •  Ac2–26 failed to stimulate phagocytosis by BMDMs isolated from Fpr2−/− mice relative to vehicle.

These data reveal novel and complex mechanisms of the FPR2/ALX receptor trafficking and functionality in the resolution of inflammation.
The lipoxin receptor ALX: potent ligand-specific and stereoselective actions in vivo.
Chiang, N., Serhan, CN, Dahlen, SE, Drazen, JM, Hay, DW, Rovati, GE, et al.
Pharmacol. Rev. 2006; 58, 463–487.      http://www.PharmacolRev.com/The_lipoxin_receptor_ALX:_potent_ligand_specific_and_stereoselective_actions_in_vivo/

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Schematic diagram indicating the complementary...

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