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Posts Tagged ‘development’

Embryogenesis in Mechanical Womb

Reporter and Curator: Dr. Sudipta Saha, Ph.D.

A highly effective platforms for the ex utero culture of post-implantation mouse embryos have been developed in the present study by scientists of the Weizmann Institute of Science in Israel. The study was published in the journal Nature. They have grown more than 1,000 embryos in this way. This study enables the appropriate development of embryos from before gastrulation (embryonic day (E) 5.5) until the hindlimb formation stage (E11). Late gastrulating embryos (E7.5) are grown in three-dimensional rotating bottles, whereas extended culture from pre-gastrulation stages (E5.5 or E6.5) requires a combination of static and rotating bottle culture platforms.

At Day 11 of development more than halfway through a mouse pregnancy the researchers compared them to those developing in the uteruses of living mice and were found to be identical. Histological, molecular and single-cell RNA sequencing analyses confirm that the ex utero cultured embryos recapitulate in utero development precisely. The mouse embryos looked perfectly normal. All their organs developed as expected, along with their limbs and circulatory and nervous systems. Their tiny hearts were beating at a normal 170 beats per minute. But, the lab-grown embryos becomes too large to survive without a blood supply. They had a placenta and a yolk sack, but the nutrient solution that fed them through diffusion was no longer sufficient. So, a suitable mechanism for blood supply is required to be developed.

Till date the only way to study the development of tissues and organs is to turn to species like worms, frogs and flies that do not need a uterus, or to remove embryos from the uteruses of experimental animals at varying times, providing glimpses of development more like in snapshots than in live videos. This research will help scientists understand how mammals develop and how gene mutations, nutrients and environmental conditions may affect the fetus. This will allow researchers to mechanistically interrogate post-implantation morphogenesis and artificial embryogenesis in mammals. In the future it may be possible to develop a human embryo from fertilization to birth entirely outside the uterus. But the work may one day raise profound questions about whether other animals, even humans, should or could be cultured outside a living womb.

References:

https://www.nature.com/articles/s41586-021-03416-3

https://www.sciencedirect.com/science/article/pii/S0092867414000750?via%3Dihub

https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1469-185X.1978.tb00993.x

https://www.nature.com/articles/199297a0

https://rep.bioscientifica.com/view/journals/rep/35/1/jrf_35_1_018.xml

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Reporter and Curator: Dr. Sudipta Saha, Ph.D.

 

Long interspersed nuclear elements 1 (LINE1) is repeated half a million times in the human genome, making up nearly a fifth of the DNA in every cell. But nobody cared to study it and may be the reason to call it junk DNA. LINE1, like other transposons (or “jumping genes”), has the unusual ability to copy and insert itself in random places in the genome. Many other research groups uncovered possible roles in early mouse embryos and in brain cells. But nobody quite established a proper report about the functions of LINE1.

 

Geneticists gave attention to LINE1 when it was found to cause cancer or genetic disorders like hemophilia. But researchers at University of California at San Francisco suspected there was more characteristics of LINE1. They suspected that if it can be most harmless then it can be worst harmful also.

 

Many reports showed that LINE1 is especially active inside developing embryos, which suggests that the segment actually plays a key role in coordinating the development of cells in an embryo. Researchers at University of California at San Francisco figured out how to turn LINE1 off in mouse embryos by blocking LINE1 RNA. As a result the embryos got stuck in the two-cell stage, right after a fertilized egg has first split. Without LINE1, embryos essentially stopped developing.

 

The researchers thought that LINE1 RNA particles act as molecular “glue,” bringing together a suite of molecules that switch off the two-cell stage and kick it into the next phase of development. In particular, it turns off a gene called Dux, which is active in the two-cell stage.

 

LINE1’s ability to copy itself, however, seems to have nothing to do with its role in embryonic development. When LINE1 was blocked from inserting itself into the genome, the embryonic stem cells remained unaffected. It’s possible that cells in embryos have a way of making LINE1 RNA while also preventing its potentially harmful “jumping” around in the genome. But it’s unlikely that every one of the thousands of copies of LINE1 is actually being used to regulate embryonic development.

 

LINE1 is abundant in the genomes of almost all mammals. Other transposons, also once considered junk DNA, have turned out to have critical roles in development in human cells too. There are differences between mice and humans, so, the next obvious step is to study LINE1 in human cells, where it makes up 17 percent of the genome.

 

References:

 

https://www-theatlantic-com.cdn.ampproject.org/c/s/www.theatlantic.com/amp/article/563354/

 

https://www.ncbi.nlm.nih.gov/pubmed/29937225

 

https://www.nature.com/scitable/topicpage/transposons-the-jumping-genes-518

 

https://www.sciencedaily.com/releases/2018/06/180621141038.htm

 

https://www.ncbi.nlm.nih.gov/pubmed/16015595

 

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The Rutgers Global Health Institute, part of Rutgers Biomedical and Health Sciences, Rutgers University, New Brunswick, New Jersey – A New Venture Designed to Improve Health and Wellness Globally  

Author: Gail S. Thornton, M.A.

Co-Editor: The VOICES of Patients, Hospital CEOs, HealthCare Providers, Caregivers and Families: Personal Experience with Critical Care and Invasive Medical Procedures

The newly formed Rutgers Global Health Institute, part of Rutgers Biomedical and Health Sciences (RBHS) of Rutgers University, New Brunswick, New Jersey (http://rbhs.rutgers.edu/), represents a new way of thinking by providing positive health outcomes to potential patients around the world affected by disease and/or by a negative environmental impact. The goal of the Institute is three-fold:

  • to improve the health and wellness of individuals and populations around the world,
  • to create a healthier world through innovation, engineering, and technology, and
  • to educate involved citizens and effective leaders in global health.

Richard G. Marlink, M.D., a former Harvard University professor recognized internationally for research and leadership in the fight against AIDS, was recently appointed as the inaugural Henry Rutgers Professor of Global Health and Director of the Rutgers Global Health Institute.

The Rutgers Global Health Institute was formed last year after research by the University into the most significant health issues affecting under-served and under-developed populations. While conducting research for its five-year strategic plan, the RBHS looked for bold and ambitious ways that they could take advantage of the changing health care environment and band together to tackle the world’s leading health and environmental causes, contributing to the betterment of society. One of the results was the formation of the Rutgers Global Health Institute, supporting cross-functionally Rutgers faculty, scientists, and clinicians who represent the best in their respective fields of health innovation, research and patient care related to global health.

More broadly, the RBHS, created in 2013, is one of the nation’s leading – and largest — academic health centers that provides health care education, research and clinical service and care. It is an umbrella organization that encompasses eight schools – Ernest Mario School of Pharmacy, Graduate School of Biomedical Sciences, New Jersey Medical School, Robert Wood Johnson Medical School, Rutgers School of Dental Medicine, School of Health Professions, School of Nursing and School of Public Health.

In addition, the RBHS encompasses six centers and institutes that provide cancer treatment and research, neuroscience, advanced biotechnology and medicine, environmental and occupational health and health care policy and aging research. Those centers and institutes are the Brain Health Institute, Center for Advanced Biotechnology and Medicine, Environmental and Occupational Health Sciences Institute, Institute for Health, Health Care Policy and Aging Research, Rutgers Cancer Institute of New Jersey, and Rutgers Institute for Translational Medicine and Research. And lastly, the RBHS includes the University Behavioral Health Care.

Rutgers Institute For Health Building

Image SOURCE: Photograph courtesy of the Rutgers Global Health Institute, Rutgers Biomedical and Health Sciences, Rutgers University, New Brunswick, New Jersey.   

Below is my interview with the Inaugural Henry Rutgers Professor of Global Health and Director of the Rutgers Global Health Institute Richard G. Marlink, M.D., which occurred in April, 2017.

You were recently appointed as the inaugural Henry Rutgers Professor of Global Health and Director of the new Rutgers Global Health Institute at Rutgers Biomedical and Health Sciences (RBHS). What are the goals of the new Institute?

Dr. Marlink: The overarching goal of the Rutgers Global Health Institute is to improve the health and wellness of individuals and populations in need both here and around the world, to create a healthier world through innovation, engineering, and technology, and to educate involved citizens and effective leaders in global health. We will do that by building on the aspiration of our originating organization — RBHS, which is to be recognized as one of the best academic health centers in the U.S., known for its education, research, clinical care, and commitment to improving access to health care and reducing health care disparities.

As the newly formed Rutgers Global Health Institute, we are embarking on an ambitious agenda to take advantage of the changing health care environment. Working across schools and disciplines at Rutgers University, we plan to have a significant impact within at least four signature programs identified by RBHS, which are cancer, environmental and occupational health, infection and inflammation, and public health. We also will include all other parts of Rutgers, as desired, beyond RBHS.

My background as a global health researcher, physician, and leader of grassroots health care delivery will help develop programs to undertake global health initiatives that assist populations locally and around the world. I believe that involved citizens, including students, can greatly impact major societal issues.

A key role in the strategic growth of Rutgers Biomedical and Health Sciences – an umbrella organization for eight schools, four centers and institutes and a behavioral health network — is to broaden the Rutgers University’s presence in the public health community globally to improve health and wellness. How will the new Rutgers Global Health Institute be part of this growth?

Dr. Marlink: Our RBHS Chancellor Brian Strom [M.D., M.P.H.] believes that we are positioned to become one of the finest research universities in the country, working cross-functionally with our three campuses in Newark, Camden and New Brunswick. In developing the strategic plan, Dr. Strom notes that we become much stronger and more capable and productive by leveraging our strengths to collaborate and working together across disciplines to best serve the needs of our community locally and globally.

Specifically, we are formulating plans to focus on these areas: old and new infectious disease epidemics; the expanding burden of noncommunicable diseases in poor populations; the social and environmental threats to health, poverty and humanitarian crises; and inadequate local and developing country health systems. We will support the development of global health research programs university-wide, the recruitment of faculty with interests in global health, and the creation of a web-based global health resource center for faculty and students with interests in these areas.

We are still a very young part of RBHS, and of Rutgers overall, so our plans are a work in progress. As tangible examples of our commitment to improving health and wellness globally, we plan to enhance global public health by establishing links between global public health and environmental and occupational health faculty in studies related to air pollution, climate change, and pesticide health.

Another example the Institute has in the works is expanding links with the School of Engineering. In fact, we are creating a senior-level joint faculty position with the School of Engineering and Rutgers-New Brunswick. Still other plans involve forging collaborative relationships between the Rutgers Cancer Program, under the auspices of Rutgers Cancer Institute of New Jersey, which is New Jersey’s only National Cancer Institute (NCI)-designated comprehensive cancer center, and other organizations and partners around the world, especially in poor and less-developed countries.

How is the Rutgers Global Health Institute strategically prepared for changing the health care paradigm?

Dr. Marlink: We intend to be an international global health leader in the health sciences, in public health, and in other related, but non-biomedical professions. This means that we will incorporate our learnings from laboratory sciences and the clinical, behavioral, and public health sciences, as well as from engineering, business, economics, law, and social sciences. This broad approach is critical in this health care environment as accountability for patient care is shifting to large groups of providers. Health care will be more value-driven and our health care teams must work collaboratively to be innovative. Our focus on health care is now also population-based, rather than only individual-based, and we are moving from large regional centers toward community centers, even in small and remote areas of the world. We are encouraged by rapid changes in technology that will provide new opportunities for shared knowledge, patient care and research.

Additionally, we are exploring ways to identify and recruit key faculty who will increase our breadth and depth of key disease areas as well as provide guidance on how to pursue science grants from the National Institute of Health (NIH)-funded program project grants and specialized research programs.

Currently, Rutgers University receives NIH funding for research in public health, population health, health promotion, wellness, health behavior, preventive medicine, and global health.

As a researcher, scholar and leader of grassroots health care delivery, how have your past positions prepared you for this new challenge? Your last position was the Bruce A. Beal, Robert L. Beal, and Alexander S. Beal Professor of the Practice of Public Health at Harvard University’s T.H. Chan School of Public Health and Executive Director of the Harvard AIDS Initiative.

Dr. Marlink: I have been a global health practitioner, researcher, and executive leader for almost three decades. I am trained in medical oncology and HIV medicine and have conducted clinical, epidemiological and implementation research in Africa since 1985. I was first introduced to global health when finishing my Hematology/Oncology fellowship at what is now the Beth Israel Deaconess Medical Center in the mid-1980’s in Boston.

During my Hematology/Oncology fellowship and after the co-organizing the first, hospital-based AIDS care clinic in the New England region, I was trying to learn the ropes in virology and molecular biology in the laboratory group of Max Essex at Harvard University. During that time in the mid-1980s, our laboratory group along with Senegalese and French collaborators discovered the first evidence for the existence of a new human retrovirus, HIV-2, a distinct second type of human AIDS virus, with its apparent origins in West Africa.

As a clinician, I was able to assist in Senegal, helping set up clinical care and create a research cohort in Dakar for hundreds of women sex workers infected with this new human retrovirus and care for them and their families. I discovered that a little can go a long way in poor settings, such as in Senegal. I became hooked on helping create solutions to help people in poor settings in Africa and elsewhere. Long-term partnerships and friendships have subsequently been made in many developing countries. Throughout my career, I have built successful partnerships with many governments, companies, and non-profit organizations, and those relationships have been the foundation to build successful public health partnerships in poor regions of the world.

In the 1990s, I helped create the Botswana-Harvard Partnership for HIV Research and Education (BHP). Through this partnership, the Government of Botswana and BHP have worked together to combat the AIDS epidemic in Botswana. Under my direction, and in partnership with the Botswana Ministry of Health, BHP launched the KITSO AIDS Training Program in 1999. Kitso is the Setswana word for ‘knowledge.”

KITSO is the national training program for physicians, nurses, and pharmacists, which has trained more than 14,000 health professionals in HIV/AIDS care and antiretroviral treatment. KITSO training modules address issues, such as antiretroviral therapy, HIV/AIDS-related disease management, gender-specific HIV issues, task-sharing, supportive and palliative care, and various psychosocial and counseling themes.

In addition, I was the Botswana County Director for Harvard Chan School’s 3-country President’s Emergency Plan AIDS Relief (PEPFAR) grant, The Botswana PEPFAR effort includes a Clinical and Laboratory Master Training Program and the creation of the Botswana Ministry of Health’s Monitoring and Evaluation Unit. Concurrently, I was the Principal Investigator of Project HEART in five African countries with the Elizabeth Glaser Pediatric AIDS Foundation.

Also in Botswana, in 2000, I was a co-founder of a distinct partnership involving a large commitment to the Government of Botswana from the Bill and Melinda Gates and Merck Foundations.  This commitment continues as an independent non-governmental organization (NGO) to provide support for various AIDS prevention and care efforts in Botswana and the region.

All these global health experiences, it seems, have led me to my new role at the Rutgers Global Health Institute.

What is your advice for ways that the business community or university students can positively impact major societal issues?

Dr. Marlink: My advice is to be optimistic and follow that desire to want to make a difference. Margaret Mead, the American cultural anthropologist, said years ago, “Never doubt that a small group of thoughtful, committed citizens can change the world; indeed, it’s the only thing that ever has.” I believe that to be our guiding principle as we embark on this new initiative.

I also believe that students should become specialized in specific areas prior to going fully into “global health,” as they develop in their careers, since they will then add more value later. For example, students should be grounded in the theory of global health in their undergraduate studies and then develop a specialization, such as becoming a statistician, economist, or medical doctor, to make a longer and greater impact in improving global health. As for the business community, we are looking for committed individuals who are specialized in specific areas to bring their knowledge to our organization, as partners in the fight against disease, improving the environment, or helping with humanitarian issues. We are committed to improving health and wellness, increasing access to the best health care, and reducing health disparities.

What is it about your current role that you enjoy the most?

Dr. Marlink: I enjoy building research, learning, and clinical programs, as I have in the HIV arena since the early 1980s. At that time, there were limited resources and funding, but a willingness among universities, non-governmental organizations, hospitals and the pharmaceutical industry to make a difference. Today in my new role, I’d like all of us to have an impact on health and wellness for those in need – to build programs from the ground up while partnering with organizations with the same goal in mind. I know it can be done.

Over my career, when I have a patient here or in a developed country who has been diagnosed with cancer, but is cured or in remission, that puts a huge smile on my face and in my heart. It also impacts you for the rest of your life. Or when I see an infant born without HIV because of the local country programs that are put in place, that also makes me feel so fulfilled, so happy.

I have worked with many talented individuals who have become great friends and partners over my career who have helped create a positive life for under-served populations around the world. We need to remember that progress happens with one person at a time or one program at a time. That’s how you truly improve health around the world.

Headshot - 2016

Image SOURCE: Photograph of Inaugural Henry Rutgers Professor of Global Health and Director of the Rutgers Global Health Institute at Rutgers Biomedical and Health Sciences, courtesy of Rutgers University, New Brunswick, New Jersey.

Richard G. Marlink, M.D.
Inaugural Henry Rutgers Professor of Global Health

Director of the Rutgers Global Health Institute

Rutgers Biomedical and Health Sciences

Richard G. Marlink, M.D., a Harvard University professor recognized internationally for research and leadership in the fight against AIDS, was recently appointed as the inaugural Henry Rutgers Professor of Global Health and Director of a new Rutgers Global Health Institute at Rutgers Biomedical and Health Sciences (RBHS). His role is to develop the strategic growth of RBHS by broadening the Rutgers University’s presence in the public health community to improve health and wellness.

Previously, Dr. Marlink was the Bruce A. Beal, Robert L. Beal, and Alexander S. Beal Professor of the Practice of Public Health at Harvard’s T.H. Chan School of Public Health and Executive Director of the Harvard AIDS Initiative.

At the start of the AIDS epidemic, Dr. Marlink was instrumental in setting up the first, hospital-based HIV/AIDS clinic in Boston, Massachusetts, and studied the impact of the HIV virus in west and central Africa. After helping to start the Botswana-Harvard Partnership in 1996, he founded the Kitso AIDS Training Program, which would become Botswana’s national AIDS training program. Kitso means knowledge in the local Setswana language.

Dr. Marlink was the principal investigator for the Tshepo Study, the first large-scale antiretroviral treatment study in Botswana, in addition to conducting other clinical and epidemiological studies in the region. Also in Botswana, he was the country director for Harvard’s contribution to the joint Botswana and United States governments’ HIV/AIDS and TB training, monitoring and evaluation PEPFAR effort.

In the mid-1980s in Senegal, Dr. Marlink was part of the team of Senegalese, French and American researchers who discovered and then studied the second type of human AIDS virus, HIV-2. Since then, he has been involved in multiple HIV/AIDS care, treatment and prevention programs in many African countries, including in Botswana, Côte d’Ivoire (Ivory Coast), Democratic Republic of the Congo, Kenya, Lesotho, Malawi, Mozambique, Rwanda, Senegal, South Africa, Swaziland, Tanzania, Uganda, Zambia and Zimbabwe. He has also organized initiatives to enhance HIV/AIDS care in Brazil, Puerto Rico and Thailand.

Dr. Marlink has served as the scientific director, the vice president for implementation and the senior adviser for medical and scientific affairs at the Elizabeth Glaser Pediatric AIDS Foundation, where he was principal investigator of Project HEART, a five-country CDC/PEPFAR effort in Africa. That project began in 2004 and by 2011 had placed more than 1 million people living with HIV into care clinics. More than 565,000 of these people were placed on life-saving antiretroviral treatment.

Since 2000, Dr. Marlink has been the founding member of the board of directors of the African Comprehensive HIV/AIDS Partnerships, a public-partnership among the government of Botswana and the Bill and Melinda Gates and Merck Foundations to provide ongoing support for numerous HIV/AIDS prevention, care and treatment efforts in that country.

He has authored or co-authored more than 130 scientific articles; written a textbook, Global AIDS Crisis: A Reference Handbook; and co-edited the book, AIDS in Africa, 2nd Edition. Additionally, he served as chief editor for two special supplements to the journal AIDS and as executive editor of the seminal 320-author, three-volume textbook, From the Ground Up: A Guide to Building Comprehensive HIV/AIDS Care Programs in Resource Limited Settings.

A trained fellow in hematology/oncology at the Beth Israel Deaconess Medical Center at Harvard Medical School, Dr. Marlink received his medical degree from the University of New Mexico and his bachelor’s degree from Brown University.

Editor’s note:

We would like to thank Marilyn DiGiaccobe, head of Partnerships and Strategic Initiatives, at the Rutgers Global Health Institute, for the help and support she provided during this interview.

REFERENCE/SOURCE

Rutgers Biomedical and Health Sciences (http://rbhs.rutgers.edu/)

Other related articles

Retrieved from https://aids.harvard.edu/ 

Retrieved from http://b.3cdn.net/glaser/515eaa8068b5e71d44_mlbrof7xw.pdf 

Other related articles were published in this Open Access Online Scientific Journal include the following: 

2016

CRISPR/Cas9 and HIV1 

Concerns About Viruses

CD-4 Therapy for Solid Tumors

Novel Discoveries in Molecular Biology and Biomedical Science

Scientists eliminate HIV1 DNA from the genome and prevent reinfection

Double Downside of HIV CRISPR therapy

2015

Where Infection meets with Cancer: Kaposi’s sarcoma (KS) is the most common cancer in HIV-1-infected persons and is caused by one of only 7 human cancer viruses, i.e., human herpesvirus 8 (HHV-8)

Antibody shows promise as treatment for HIV

2014

AIDS: Origin of HIV pandemic ‘was 1920s Kinshasa’

2013

Scientists discover how AIDS virus enters key immune cells

Heroes in Medical Research: Dr. Robert Ting, Ph.D. and Retrovirus in AIDS and Cancer

2012

Nanotechnology and HIV/AIDS treatment

HIV vaccine: Caltech puts us One step further

Bone Marrow Transplant Eliminates Signs of HIV Infection

Getting Better: Documentary Videos on Medical Progress — in Surgery, Leukemia, and HIV/AIDS

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Reporter and Curator: Dr. Sudipta Saha, Ph.D.

Disorders of sex development include many different medical conditions. They could happen to anyone, and are actually more common than you might think. You may have heard DSD called terms such as “intersex” or “hermaphrodite” or “pseudohermaphroditism.” However, a meeting of international experts reached consensus that the term “disorders of sex development” should replace those terms. Because there are so many stages of sex development in human life, there are a lot of opportunities for a person to develop along a path that is not the average one for a boy or a girl. When a less-common path of sex development is taken, the condition is often called a “disorder of sex development” or DSD. So DSD is a name given to a lot of different variations of sex development.

These conditions have specific names, and include:

  • 46,XX congenital adrenal hyperplasia (CAH)
  • Testosterone biosynthetic defects
  • Androgen insensitivity syndrome (AIS)—can be partial (PAIS) or complete (CAIS)
  • Gonadal dysgenesis (partial and complete)
  • Swyer syndrome (46,XY gonadal dysgenesis)
  • 5-alpha reductase deficiency (5-AR deficiency)
  • 46,XY micropenis
  • Klinefelter syndrome (47,XXY)
  • Turner syndrome (45,X)
  • Hypospadias
  • Epispadias
  • Mayer-Rokitansky-Kuster-Hauser syndrome (Also called MRKH, Müllerian agenesis and vaginal agenesis)
  • Sex-chromosome mosaicism (for example mixed gonadal dysgenesis (45,X/46,XY; sometimes referred to as XY Turners)
  • 46,XX/46,XY (chimeric, ovotesticular DSD)
  • Persistant Müllerian duct syndrome
  • Kallman syndrome
  • 17-beta reductase deficiency (XX or XY)
  • 46,XY 3-beta-hydroxysteroid dehydrogenase deficiency (HSD deficiency)
  • Aphallia
  • Clitoromegaly
  • 46,XY cloacal exstrophy
  • Progestin-induced virilization

The symptoms associated with intersex will depend on the underlying cause, but may include:

  • Ambiguous genitalia at birth
  • Micropenis
  • Clitoromegaly (an enlarged clitoris)
  • Partial labial fusion
  • Apparently undescended testes (which may turn out to be ovaries) in boys
  • Labial or inguinal (groin) masses — which may turn out to be testes — in girls
  • Hypospadias [the opening of the penis is somewhere other than at the tip; in females, the urethra (urine canal) opens into the vagina]
  • Otherwise unusual appearing genitalia at birth
  • Electrolyte abnormalities
  • Delayed or absent puberty
  • Unexpected changes at puberty

Disorders of sex development (DSD) with or without ambiguous genitalia require medical attention to reach a definite diagnosis. Advances in identification of molecular causes of abnormal sex, heightened awareness of ethical issues and this necessitated a re-evaluation of nomenclature. The term DSD was proposed for congenital conditions in which chromosomal, gonadal or anatomical sex is atypical. In general, factors influencing sex determination are transcriptional regulators, whereas factors important for sex differentiation are secreted hormones and their receptors.The current intense debate on the management of patients with intersexuality and related conditions focus on four major issues: 1) aetiological diagnosis, 2) assignment of gender, 3) indication for and timing of genital surgery, 4) the disclosure of medical information to the patient and his/her parents. The psychological and social implications of gender assignment require a multidisciplinary approach and a team which includes ageneticist, neonatologist, endocrinologist, gynaecologist, psychiatrist, surgeon and a social worker. Each patient should be evaluated individually by multidisciplinary approach.

Source References:

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3184510/

http://en.wikipedia.org/wiki/Disorders_of_sex_development

http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0002634/

http://www.med.umich.edu/yourchild/topics/dsd.htm

http://www.accordalliance.org/dsd-guidelines.html

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FDA Guidelines For Developmental and Reproductive Toxicology (DART) Studies for Small Molecules. Author-Writer: Stephen J. Williams, Ph.D.

This posting is a follow-up on the Report on the Fall Mid-Atlantic Society of Toxicology Meeting “Reproductive Toxicology of Biologics: Challenges and Considerations post and gives a brief synopsis of the current state of FDA regulatory guidelines with respect to DART studies on small molecule (non-biological based) therapeutics.    The following is adapted from the book Principles and Methods of Toxicology by Dr. A Wallace Hayes (1) and is an excellent reference on reproductive toxicology and testing methods.

Chemical insult occurs to the human reproductive system at a multitude of stages in development and the life cycle, leading to the extensive testing which must be performed to diligently the reproductive and development toxicity of a chemical/drug.  Abnormalities and toxic manifestations in the offspring may result from insult to the adult reproductive (either female or male) and neuroendocrine systems, as well as damage to the embryo resulting in embryolethality, fetus at any period during organogenesis, juvenile development or, in the case of certain antibody therapies, immune system development.  The latter, toxic insult to the developing immune system could possibly be manifested as either an immune defect in the newborn or, later in life, as tolerance to said therapy.  It is estimated that exposure to the pregnant woman, of either environmental contaminants or drug, is significant.  It is estimated that a mother may be taking an average of 8-9 different drug preparations, mostly over the counter preparations such as antacids, vitamin preparations, cathartics etc. with the maximal drug intake occurring between 24 and 36 weeks of gestation.

Toxic insult to the developing embryo is dependent on

  • Fetal development stage during drug/chemical exposure
  • Maternal/placental xenobiotic metabolism
  • Pharmacokinetic parameters affecting bioavailability and fetal/maternal drug binding

The following table shows the dependency of developmental stage to teratogenicity: adapted from J. Manson, H. Zenick, and R.D. Costlow from Principles and Methods of Toxicology.

Developmental Stage Major Susceptibility
Preimplantation Embryolethality
Organogenesis Births defects; embryolethality
Fetal Growth retardation, fetal death, functional deficits
Neonatal Growth retardation, nervous system alterations, immune and endocrine systems

It is not generally accepted that there is a dose dependency of teratogenesis however most teratogens have specific mechanisms of action and teratogenic effects occur at much lower doses than result in maternal toxicity.   However, the developmental toxicity may be manifested later in life, including as reproductive toxicity affecting adult fertility and familial generations.

FDA Guidelines for DART Studies on Non-Biologics (Small Molecule Therapeutics)

The basic design for DART studies incorporate the aforementioned principles of tetralogy:

  • developmental stage of fetal exposure
  • parental effects on reproduction and development
  • toxicity may be manifested over multiple generations including fertility rates

Therefore two designs are generally used for DART studies

  1. exposure across several generations
  2. exposure during one generation

FDA requires one control group and two treatment groups, and evaluation of at least two species.  However, most studies will use two rodent and one nonrodent species.

Multigenerational Design

Multigenerational DART studies are conducted for compounds likely to concentrate in the body following long-term exposure.  Examples of types of compounds include pesticides and food additives.

Figure 1.  General Design of a Multigenerational DART study.  Weanlings (30-30 days of age) from the parental generation are treated for a period up to 60 days. At 100-120 days of parental generation, animals are mated.  Fx = filialx .

Three Segment, Single Generation Tests

The single generation design is more suitable for DART studies on drugs, as most therapeutic would be taken over short periods (during pregnancy) and have relatively short half-lives in the body.  FDA guidelines separate these studies in three phases:

I.            Phase I: evaluation of fertility and general reproductive performance

II.            Phase II: assessment of teratogenicity and embryotoxicity

III.            Phase III: peri- and postnatal evaluations.

All figures are adapted from Principles and Methods of Toxicology.(1)

FDA guidelines Guidance for Industry Reproductive and Developmental Toxicities —Integrating Study Results to Assess Concerns can be found at: http://www.fda.gov/downloads/Drugs/GuidanceComplianceRegulatoryInformation/Guidances/ucm079240.pdf

FDA Guideline for reproductive toxicity testing for small molecule therapeutics can be found at:

http://www.fda.gov/downloads/Drugs/GuidanceComplianceRegulatoryInformation/Guidances/ucm074950.pdf

1.            Hayes, A. W. (1986) Principles and Methods of Toxicology, Raven Press, New York

Other research papers on Pharmaceutical Intelligence and Reproductive Biology, Bio Insrumentation, Endocrinology Genetics were published on this Scientific Web site as follows

Non-small Cell Lung Cancer drugs – where does the Future lie?

Reboot evidence-based medicine and reconsider the randomized, placebo-controlled clinical trial

Every sperm is sacred: Sequencing DNA from individual cells vs “humans as a whole.”

Leptin and Puberty

Gene Trap Mutagenesis in Reproductive Research

Genes involved in Male Fertility and Sperm-egg Binding

Hope for Male Contraception: A small molecule that inhibits a protein important for chromatin organization can cause reversible sterility in male mice

Pregnancy with a Leptin-Receptor Mutation

The contribution of comparative genomic hybridization in reproductive medicine

Sperm collide and crawl the walls in chaotic journey to the ovum

Impact of evolutionary selection on functional regions: The imprint of evolutionary selection on ENCODE regulatory elements is manifested between species and within human populations

Biosimilars: CMC Issues and Regulatory Requirements

Biosimilars: Intellectual Property Creation and Protection by Pioneer and by Biosimilar Manufacturers

Assisted Reproductive Technology Cycles and Cumulative Birth Rates

Innovations in Bio instrumentation in Reproductive Clinical and Male Fertility Labs in the US

Increased risks of obesity and cancer, Decreased risk of type 2 diabetes: The role of Tumor-suppressor phosphatase and tensin homologue (PTEN)

Guidelines for the welfare and use of animals in cancer research

Every sperm is sacred: Sequencing DNA from individual cells vs “humans as a whole.”

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Reporter: Sudipta Saha, Ph.D.

 

Beyond characterization of the fundamental anatomy of vascular development, the first investigators in this field participated in one of the classic debates in all of developmental biology: where and when do endothelial cells (and hence blood vessels) arise in the developing embryo? Because blood vessels are first observed in the yolk sac in avian and mammalian embryos. It was initially assumed that all blood vessels arise from extra-embryonic tissues. However, careful histological analysis subsequently indicated that isolated foci of endothelial cells can also be observed in the embryo proper, which suggested that blood vessels arise from an intraembryonic source (specifically, the mesoderm) rather than via colonization. The formation of new blood vessels in the adult organism not only contributed to the progression of diseases such as cancer and diabetic retinopathy but also can be promoted in therapeutic approaches to various ischemic pathologies. Because many of the signals important to blood vessel development during embryogenesis are recapitulated during adult blood vessel formation, much work has been performed to better-understand the molecular control of endothelial differentiation in the developing embryo. Activators and inhibitors of developmental pathways have been tested for their ability to modulate angiogenesis in early phase clinical trials, and in the case of anti-Flk1 antibodies clinical utility has been demonstrated for anti-tumor strategies. Analyses of circulating endothelial progenitor cells, which have angiogenic potential, do indeed suggest that there are similarities in the biology of these cells compared with developmental endothelial precursors. Stem cell therapeutics therefore represents another potential arena for translation of insights from vascular development to clinical practice. Even though our understanding of endothelial development is much richer than it was even a few years ago and despite the potential applications of this knowledge in clinical medicine, there are still a number of key issues on this topic that remain to be resolved. Precisely how early are endothelial precursors specified during development, and what is the nature of this progenitor cell pool? What are the relationships among signaling pathways that specify endothelial fates in a coordinated fashion? Is there a transcriptional hierarchy that regulates vascular development? The answers to these and other questions about endothelial development are likely to be forthcoming in the near future as experimental methods continue to evolve (http://atvb.ahajournals.org/content/25/11/2246.full).

 

The development of the vertebrate heart can be considered an additive process, in which additional layers of complexity have been added throughout the evolution of a simple structure (linear heart tube) in the form of modular elements (atria, ventricles, septa, and valves). Each modular element confers an added capacity to the vertebrate heart and can be identified as individual structures patterned in a precise manner. An understanding of the individual modular steps in cardiac morphogenesis is particularly relevant to congenital heart disease, which usually involves defects in specific structural components of the developing heart. Organ formation requires the precise integration of cell type-specific gene expression and morphological development; both are intertwined in their regulation by transcription factors. Although many transcription factors have been described as regulators of cardiac-specific gene expression, the transcriptional regulation of cardiac morphogenesis is still not well explored. For a transcription factor to be considered directly involved in heart development, it must be expressed in developing heart tissues and exert an influence on processes that impact the morphogenesis of the developing heart. Transcription factors can regulate the expression of other genes in a tissue-specific and quantitative manner and are thus major regulators of embryonic developmental processes. A number of complex transcriptional networks and interactions are involved in the morphogenesis of the developing vertebrate heart. The identities of crucial regulators involved in defined events in cardiogenesis are being uncovered at a rapid rate, but a number of critical questions remain. First and foremost, it is still not known which transcription factors are involved in the earliest differentiation of cardiac cells from the mesoderm. Second, the downstream pathways regulated by transcription factors responsible for key morphogenetic events are still largely unknown. Third, the concept of maintained function or redeployment of functions throughout various stages of development remains to be addressed in detail. The challenge for the future lies in defining pathways downstream from cardiac transcription factors and understanding the intersection of these pathways as the heart develops from a simple patterned structure into a complex multifunctional organ (http://circres.ahajournals.org/content/90/5/509.full).

 

Tissue development and regeneration involve tightly coordinated and integrated processes: selective proliferation of resident stem and precursor cells, differentiation into target somatic cell type, and spatial morphological organization. The role of the mechanical environment in the coordination of these processes is poorly understood. It has been reported that multipotent cells derived from native cardiac tissue continually monitored cell substratum rigidity and showed enhanced proliferation, endothelial differentiation, and morphogenesis when the cell substratum rigidity closely matched that of myocardium. Mechanoregulation of these diverse processes required p190RhoGAP, a guanosine triphosphatase-activating protein for RhoA, acting through RhoA-dependent and -independent mechanisms. Natural or induced decreases in the abundance of p190RhoGAP triggered a series of developmental events by coupling cell-cell and cell-substratum interactions to genetic circuits controlling differentiation (http://www.ncbi.nlm.nih.gov/pubmed/22669846).

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