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Archive for the ‘Cell Biology’ Category


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

During pregnancy, the baby is mostly protected from harmful microorganisms by the amniotic sac, but recent research suggests the baby could be exposed to small quantities of microbes from the placenta, amniotic fluid, umbilical cord blood and fetal membranes. One theory is that any possible prenatal exposure could ‘pre-seed’ the infant microbiome. In other words, to set the right conditions for the ‘main seeding event’ for founding the infant microbiome.

When a mother gives birth vaginally and if she breastfeeds, she passes on colonies of essential microbes to her baby. This continues a chain of maternal heritage that stretches through female ancestry for thousands of generations, if all have been vaginally born and breastfed. This means a child’s microbiome, that is the trillions of microorganisms that live on and in him or her, will resemble the microbiome of his/her mother, the grandmother, the great-grandmother and so on, if all have been vaginally born and breastfed.

As soon as the mother’s waters break, suddenly the baby is exposed to a wave of the mother’s vaginal microbes that wash over the baby in the birth canal. They coat the baby’s skin, and enter the baby’s eyes, ears, nose and some are swallowed to be sent down into the gut. More microbes form of the mother’s gut microbes join the colonization through contact with the mother’s faecal matter. Many more microbes come from every breath, from every touch including skin-to-skin contact with the mother and of course, from breastfeeding.

With formula feeding, the baby won’t receive the 700 species of microbes found in breast milk. Inside breast milk, there are special sugars called human milk oligosaccharides (HMO’s) that are indigestible by the baby. These sugars are designed to feed the mother’s microbes newly arrived in the baby’s gut. By multiplying quickly, the ‘good’ bacteria crowd out any potentially harmful pathogens. These ‘good’ bacteria help train the baby’s naive immune system, teaching it to identify what is to be tolerated and what is pathogen to be attacked. This leads to the optimal training of the infant immune system resulting in a child’s best possible lifelong health.

With C-section birth and formula feeding, the baby is not likely to acquire the full complement of the mother’s vaginal, gut and breast milk microbes. Therefore, the baby’s microbiome is not likely to closely resemble the mother’s microbiome. A baby born by C-section is likely to have a different microbiome from its mother, its grandmother, its great-grandmother and so on. C-section breaks the chain of maternal heritage and this break can never be restored.

The long term effect of an altered microbiome for a child’s lifelong health is still to be proven, but many studies link C-section with a significantly increased risk for developing asthma, Type 1 diabetes, celiac disease and obesity. Scientists might not yet have all the answers, but the picture that is forming is that C-section and formula feeding could be significantly impacting the health of the next generation. Through the transgenerational aspect to birth, it could even be impacting the health of future generations.

References:

https://blogs.scientificamerican.com/guest-blog/shortchanging-a-babys-microbiome/

https://www.ncbi.nlm.nih.gov/pubmed/23926244

https://www.ncbi.nlm.nih.gov/pubmed/26412384

https://www.ncbi.nlm.nih.gov/pubmed/25290507

https://www.ncbi.nlm.nih.gov/pubmed/25974306

https://www.ncbi.nlm.nih.gov/pubmed/24637604

https://www.ncbi.nlm.nih.gov/pubmed/22911969

https://www.ncbi.nlm.nih.gov/pubmed/25650398

https://www.ncbi.nlm.nih.gov/pubmed/27362264

https://www.ncbi.nlm.nih.gov/pubmed/27306663

http://www.mdpi.com/1099-4300/14/11/2036

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4464665/

https://www.ncbi.nlm.nih.gov/pubmed/24848255

https://www.ncbi.nlm.nih.gov/pubmed/26412384

https://www.ncbi.nlm.nih.gov/pubmed/28112736

http://ndnr.com/gastrointestinal/the-infant-microbiome-how-environmental-maternal-factors-influence-its-development/

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3D Liver Model in a Droplet

Curator: Marzan Khan, BSc

Recently, a Harvard University Professor of Physics and Applied Physics, David Weitz and his team of researchers have successfully generated 3D models of liver tissue composed of two different kinds of liver cells, precisely compartmentalized in a core-shell droplet, using the microfluidics approach(1). Compared to alternative in-vitro methods, this approach comes with more advantages – it is cost-effective, can be quickly assembled and produces millions of organ droplets in a second(1). It is the first “organ in a droplet” technology that enables two disparate liver cells to physically co-exist and exchange biochemical information, thus making it a good mimic of the organ in vivo(1).

Liver tissue models are used by researchers to investigate the effect of drugs and other chemical compounds, either alone or in combination on liver toxicity(2). The liver is the primary center of drug metabolism, detoxification and removal and all of these processes need to be carried out systematically in order to maintain a homeostatic environment within the body(2) Any deviation from the steady state will shift the dynamic equilibrium of metabolism, leading to production of reactive oxygen species (ROS)(2). These are harmful because they will exert oxidative stress on the liver, and ultimately cause the organ to malfunction. Drug-induced liver toxicity is a critical problem – 10% of all cases of acute hepatitis, 5% of all hospital admissions, and 50% of all acute liver failures are caused by it(2).

Before any novel drug is launched into the market, it is tested in-vitro, in animal models, and then progresses onto human clinical trials(1). Weitz’s system can produce up to one-thousand organ droplets per second, each of which can be used in an experiment to test for drug toxicity(1). Clarifying further, he asserts that “Each droplet is like a mini experiment. Normally, if we are running experiments, say in test tubes, we need a milliliter of fluid per test tube. If we were to do a million experiments, we would need a thousand liters of fluid. That’s the equivalent of a thousand milk jugs! Here, each droplet is only a nanoliter, so we can do the whole experiment with one milliliter of fluid, meaning we can do a million more experiments with the same amount of fluid.”

Testing hepatocytes alone on a petri dish is a poor indicator of liver-specific functions because the liver is made up of multiple cells systematically arranged on an extracellular matrix and functionally interdependent(3). The primary hepatocytes, hepatic stellate cells, Kupffer cells, endothelial cells and fibroblasts form the basic components of a functioning liver(3). Weitz’s upgraded system contains hepatocytes (that make up the majority of liver cells and carry out most of the important functions) supported by a network of fibroblasts(3). His microfluidic chip is comprised of a network of constricted, circular channels spanning the micrometer range, the inner phase of which contains hepatocytes mixed in a cell culture solution(3). The surrounding middle phase accommodates fibroblasts in an alginate solution and the two liquids remain separated due to differences in their chemical properties as well as the physics of fluids travelling in narrow channels. Addition of a fluorinated carbon oil interferes with the two aqueous layers, forcing them to become individual monodisperse droplets(3). The hydrogel shell is completed when a 0.15% solution of acetic acid facilitates the cross-linking of alginate to form a gelatinous shell, locking the fibroblasts in place(3). Thus, the aqueous core of hepatocytes are encapsulated by fibroblasts confined to a strong hydrogel network, creating a core-shell hydrogel scaffold of 3D liver micro-tissue in a droplet(3). Using empirical analysis, scientists have shown that albumin secretion and urea synthesis (two important markers of liver function) were significantly higher in a co-culture of hepatocytes and fibroblasts 3D core-shell spheroids compared to a monotypic cell-culture of hepatocyte-only spheroids(3). These results validate the theory that homotypic as well as heterotypic communication between cells are important to achieve optimal organ function in vitro(3).

This system of creating micro-tissues in a droplet with enhanced properties is a step-forward in biomedical science(3). It can be used in experiments to test for a myriad of drugs, chemicals and cosmetics on different human tissue samples, as well as to understand the biological connectivity of contrasting cells(3).

diagram

Image source: DOI: 10.1039/c6lc00231

A simple demonstration of the microfluidic chip that combines different solutions to create a core-shell droplet consisting of two different kinds of liver cells.

References:

  1. National Institute of Biomedical Imaging and Bioengineering. (2016, December 13). New device creates 3D livers in a droplet.ScienceDaily. Retrieved February 9, 2017 from https://www.sciencedaily.com/releases/2016/12/161213112337.htm
  2. Singh, D., Cho, W. C., & Upadhyay, G. (2015). Drug-Induced Liver Toxicity and Prevention by Herbal Antioxidants: An Overview.Frontiers in Physiology,6, 363. http://doi.org/10.3389/fphys.2015.00363
  3. Qiushui Chen, Stefanie Utech, Dong Chen, Radivoje Prodanovic, Jin-Ming Lin and David A. Weitz; Controlled assembly of heterotypic cells in a core– shell scaffold: organ in a droplet; Lab Chip, 2016, 16, 1346; DOI: 10.1039/c6lc00231

Other related articles on 3D on a Chip published in this Open Access Online Scientific Journal include the following:

 

What could replace animal testing – ‘Human-on-a-chip’ from Lawrence Livermore National Laboratory

Reporter: Aviva Lev-Ari, PhD, RN

AGENDA for Second Annual Organ-on-a-Chip World Congress & 3D-Culture Conference, July 7-8, 2016, Wyndham Boston Beacon Hill by SELECTBIO US

Reporter: Aviva Lev-Ari, PhD, RN

Medical MEMS, BioMEMS and Sensor Applications

Curator and Reporter: Aviva Lev-Ari, PhD, RN

Contribution to Inflammatory Bowel Disease (IBD) of bacterial overgrowth in gut on a chip

Larry H. Bernstein, MD, FCAP, Curator

Current Advances in Medical Technology

Larry H. Bernstein, MD, FCAP, Curator

 

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

 

Alnylam down as it halts development for RNAi liver disease candidate

by Stacy Lawrence

LIVE 9/21 8AM to 2:40PM Targeting Cardio-Metabolic Diseases: A focus on Liver Fibrosis and NASH Targets at CHI’s 14th Discovery On Target, 9/19 – 9/22/2016, Westin Boston Waterfront, Boston

Reporter: Aviva Lev-Ari, PhD, RN

2016 Nobel in Economics for Work on The Theory of Contracts to winners: Oliver Hart and Bengt Holmstrom

Reporter: Aviva Lev-Ari, PhD, RN

LIVE 9/20 2PM to 5:30PM New Viruses for Therapeutic Gene Delivery at CHI’s 14th Discovery On Target, 9/19 – 9/22/2016, Westin Boston Waterfront, Boston

Reporter: Aviva Lev-Ari, PhD, RN

Seven Cancers: oropharynx, larynx, oesophagus, liver, colon, rectum and breast are caused by Alcohol Consumption

Reporter: Aviva Lev-Ari, PhD, RN

 

Other related articles on 3D on a Chip published in this Open Access Online Scientific Journal include the following:

 

Liquid Biopsy Chip detects an array of metastatic cancer cell markers in blood – R&D @Worcester Polytechnic Institute,  Micro and Nanotechnology Lab

Reporters: Tilda Barliya, PhD and Aviva Lev-Ari, PhD, RN

Trovagene’s ctDNA Liquid Biopsy urine and blood tests to be used in Monitoring and Early Detection of Pancreatic Cancer

Reporters: David Orchard-Webb, PhD and Aviva Lev-Ari, PhD, RN

Liquid Biopsy Assay May Predict Drug Resistance

Curator: Larry H. Bernstein, MD, FCAP

One blood sample can be tested for a comprehensive array of cancer cell biomarkers: R&D at WPI

Curator: Marzan Khan, B.Sc

Real Time Coverage of the AGENDA for Powering Precision Health (PPH) with Science, 9/26/2016, Cambridge Marriott Hotel, Cambridge, MA

Reporter: Aviva Lev-Ari, PhD, RN

 

 

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

Researchers have classified a brand-new organ inside human body. Known as the mesentery, the new organ is found in our digestive systems, and was long thought to be made up of fragmented, separate structures. But recent research has shown that it’s actually one, continuous organ. The evidence for the organ’s reclassification is now published in The Lancet Gastroenterology & Hepatology. Although we now know about the structure of this new organ, its function is still poorly understood, and studying it could be the key to better understanding and treatment of abdominal and digestive disease.

mesentery

J Calvin Coffey, a researcher from the University Hospital Limerick in Ireland, who first discovered that the mesentery was an organ. In 2012, Coffey and his colleagues showed through detailed microscopic examinations that the mesentery is actually a continuous structure. Over the past four years, they’ve gathered further evidence that the mesentery should actually be classified as its own distinct organ, and the latest paper makes it official. Mesentery is a double fold of peritoneum – the lining of the abdominal cavity – that holds our intestine to the wall of our abdomen. It was described by the Italian polymath Leanardo da Vinci in 1508, but it has been ignored throughout the centuries, until now. Although there are generally considered to be five organs in the human body, there are in fact now 79, including the mesentery. The heart, brain, liver, lungs and kidneys are the vital organs, but there are another 74 that play a role in keeping us healthy. The distinctive anatomical and functional features of mesentery have been revealed that justify designation of the mesentery as an organ. Accordingly, the mesentery should be subjected to the same investigatory focus that is applied to other organs and systems. This provides a platform from which to direct future scientific investigation of the human mesentery in health and disease.

References:

http://www.thelancet.com/journals/langas/article/PIIS2468-1253(16)30026-7/abstract

http://www.sciencealert.com/it-s-official-a-brand-new-human-organ-has-been-classified

http://www.bbc.com/news/health-38506708

http://www.independent.co.uk/news/science/new-organ-mesentery-found-human-body-digestive-system-classified-abdominal-grays-anatomy-a7507396.html

https://in.news.yahoo.com/scientists-discover-human-organ-064207997.html

https://en.wikipedia.org/wiki/Mesentery

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Translation of whole human genome sequencing to clinical practice: The Joint Initiative for Metrology in Biology (JIMB) is a collaboration between the National Institute of Standards & Technology (NIST) and Stanford University.

Reporter: Aviva Lev-Ari, PhD, RN

 

JIMB’s mission is to advance the science of measuring biology (biometrology). JIMB is pursuing fundamental research, standards development, and the translation of products that support confidence in biological measurements and reliable reuse of materials and results. JIMB is particularly focused on measurements and technologies that impact, are related to, or enabled by ongoing advances in and associated with the reading and writing of DNA.

Stanford innovators and industry entrepreneurs have joined forces with the measurement experts from NIST to create a new engine powering the bioeconomy. It’s called JIMB — “Jim Bee” — the Joint Initiative for Metrology in Biology. JIMB unites people, platforms, and projects to underpin standards-based research and innovation in biometrology.

Genome in a Bottle
Authoritative Characterization of
Benchmark Human Genomes


The Genome in a Bottle Consortium is a public-private-academic consortium hosted by NIST to develop the technical infrastructure (reference standards, reference methods, and reference data) to enable translation of whole human genome sequencing to clinical practice. The priority of GIAB is authoritative characterization of human genomes for use in analytical validation and technology development, optimization, and demonstration. In 2015, NIST released the pilot genome Reference Material 8398, which is genomic DNA (NA12878) derived from a large batch of the Coriell cell line GM12878, characterized for high-confidence SNPs, indel, and homozygous reference regions (Zook, et al., Nature Biotechnology 2014).

There are four new GIAB reference materials available.  With the addition of these new reference materials (RMs) to a growing collection of “measuring sticks” for gene sequencing, we can now provide laboratories with even more capability to accurately “map” DNA for genetic testing, medical diagnoses and future customized drug therapies. The new tools feature sequenced genes from individuals in two genetically diverse groups, Asians and Ashkenazic Jews; a father-mother-child trio set from Ashkenazic Jews; and four microbes commonly used in research. For more information click here.  To purchase them, visit:

Data and analyses are publicly available (GIAB GitHub). A description of data generated by GIAB is published here. To standardize best practices for using GIAB genomes for benchmarking, we are working with the Global Alliance for Genomics and Health Benchmarking Team (benchmarking tools).

High-confidence small variant and homozygous reference calls are available for NA12878, the Ashkenazim trio, and the Chinese son with respect to GRCh37.  Preliminary high-confidence calls with respect to GRCh38 are also available for NA12878.   The latest version of these calls is under the latest directory for each genome on the GIAB FTP.

The consortium was initiated in a set of meetings in 2011 and 2012, and the consortium holds open, public workshops in January at Stanford University in Palo Alto, CA and in August/September at NIST in Gaithersburg, MD. Slides from workshops and conferences are available online. The consortium is open and welcomes new participants.

SOURCE

Stanford innovators and industry entrepreneurs have joined forces with the measurement experts from NIST to create a new engine powering the bioeconomy. It’s called JIMB — “Jim Bee” — the Joint Initiative for Metrology in Biology. JIMB unites people, platforms, and projects to underpin standards-based research and innovation in biometrology.

JIMB World Metrology Day Symposium

JIMB’s mission is to motivate standards-based measurement innovation to facilitate translation of basic science and technology development breakthroughs in genomics and synthetic biology.

By advancing biometrology, JIMB will push the boundaries of discovery science, accelerate technology development and dissemination, and generate reusable resources.

 SOURCE

VIEW VIDEO

https://player.vimeo.com/video/184956195?wmode=opaque&api=1″,”url”:”https://vimeo.com/184956195″,”width”:640,”height”:360,”providerName”:”Vimeo”,”thumbnailUrl”:”https://i.vimeocdn.com/video/594555038_640.jpg”,”resolvedBy”:”vimeo”}” data-block-type=”32″>

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

“Genome in a Bottle”: NIST’s new metrics for Clinical Human Genome Sequencing

Reporter: Aviva Lev-Ari, PhD, RN

https://pharmaceuticalintelligence.com/2012/09/06/genome-in-a-bottle-nists-new-metrics-for-clinical-human-genome-sequencing/

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Li -Fraumeni Syndrome and Pancreatic Cancer

Curator: Marzan Khan, B.Sc.

Li-Fraumeni syndrome (LFS) is a condition that makes individuals prone to developing a wide variety of cancers that occur early on in life, the most common types being- soft tissue sarcoma, osteosarcoma, breast cancer, brain tumors, adrenocortical carcinoma (ACC), and leukemia. (1) Pancreatic cancer is minimally associated with the condition. (2) A survey found the presence of pancreatic cancer in only 1% of 475 tumor samples collected from 91 families who were carriers of p53 mutations, with half of them having LFS. The incidence of breast cancer amongst them was the highest -24%. (2) Pancreatic carcinoma in LFS patients usually occurs in the later stages of life. (3)

The underlying cause of LFS is germline mutations in TP53 gene on chromosome 17p, that encodes the transcription factor p53, crucial in cell cycle regulation and the repair of damaged and/or abnormal cells. (4) In the majority of cases, this mutation is obtained by inheritance. (5) De-novo germline mutations in p53 occur in 7%-20% of the cases. (5)

A person showing symptoms of any type of cancer at an early age or having first or second-degree relatives with cancer are at risk of developing LFS. (5) That is why tracing family history is an important part of diagnosis in LFS patients. Genetic testing can confirm mutations present in the gene, however, there are controversial ethical issues regarding their use, particularly in children and fetuses.

In patients with LFS, it is important to control the manifestations of the disease. They should be monitored closely so that any new cancers that arise are diagnosed and treated during the early stages. (6) Patients are also at risk of developing radiation-induced second and third primary tumors. (6) Therefore, radiation and alkylating agents should be used minimally (6) People at risk can be cautioned to avoid exposure to carcinogens such as sunlight, cigarette smoke, and alcohol consumption. (5) Therapeutic approaches that are aimed at restoring wild-type p53 by gene therapy as well as reactivating non-functional p53 by the use of small-molecule drugs are currently being investigated in many cancers. (7) Unlike radiation therapy, these small-molecule drugs are non-toxic to healthy cells, thus eliminating the risk of forming new tumors.

So far, PRIMA-1 has proven to be quite effective at correcting non-functional p53. (8) PRIMA-1 is changed to its methylated form, PRIMA-1MET   that forms covalent adducts to thiol groups in the mutated protein and modifies them. (8) As a result, p53 regains its ability to destroy malignant cells. (8) A research study also found that PRIMA-1 induces apoptosis and increases the sensitivity of pancreatic cancer cells to various chemotherapeutic agents. (9)

  1. Magali Olivier, David E. Goldgar, Nayanta Sodha, Hiroko Ohgaki, Paul Kleihues, Pierre Hainaut and Rosalind A. Eeles. Li-Fraumeni and Related Syndromes. Cancer Res October 15 2003 63 (20) 6643-6650 http://cancerres.aacrjournals.org/content/63/20/6643.abstract
  2. Kleihues P, Schauble B, zur Hausen H, et al. Tumors associated with p53 germline mutations: a synopsis of 91 families. Am J Pathol 1997; 150:1-13 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1858532/
  3. John P. Neoptolemos, Raul Urrutia, James L. Abbruzzese, Markus W. Buchler. Pancreatic Cancer. 2010.1st ed, pp-6, 2010, Springer, Verlag, New York
  4. Mishra B and Patel RR. Gene Therapy for Treatment of Pancreatic Cancer. Austin Therapeutics. 2014;1(1): 10. https://books.google.ca/books?id=NmBB5ZoKkk4C&pg=PA6&lpg=PA6&dq=connection+between+li+fraumeni+and+Pancreatic+cancer&source=bl&ots=H0iCeaPP0N&sig=pqJT1tPMR6C-NIig3S_NkFKFsD0&hl=en&sa=X&ved=0ahUKEwi4nLrgzuPQAhUUIWMKHS3wBoc4ChDoAQhNMAg#v=onepage&q=connection%20between%20li%20fraumeni%20and%20Pancreatic%20cancer&f=false
  5. Schneider K, Zelley K, Nichols KE, et al. Li-Fraumeni Syndrome. 1999 Jan 19 [Updated 2013 Apr 11]. In: Pagon RA, Adam MP, Ardinger HH, et al., editors. GeneReviews® [Internet]. Seattle (WA): University of Washington, Seattle; 1993-2016. https://www.ncbi.nlm.nih.gov/pubmed/20301488
  6. Elisa Becze BA, ELS, 2011 Mar 1. An introduction to Li-Fraumeni Syndrome, Five-Minute-In-Service. http://connect.ons.org/columns/five-minute-in-service/an-introduction-to-li-fraumeni-syndrome
  7. Sorrell, A. D., Espenschied, C. R., Culver, J. O., & Weitzel, J. N. (2013).TP53Testing and Li-Fraumeni Syndrome: Current Status of Clinical Applications and Future Directions. Molecular Diagnosis & Therapy17(1), 31–47. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3627545/
  8. Emily J. Lewis. PRIMA-1 as a cancer therapy restoring mutant p53: a reviewBioscience Horizons (2015) 8: hzv006 http://biohorizons.oxfordjournals.org/content/8/hzv006.full
  9. Izetti, Patricia, Agnes Hautefeuille, Ana Lucia Abujamra, Caroline Brunetto de Farias, Juliana Giacomazzi, Bárbara Alemar, Guido Lenz, et al. ‘PRIMA-1, a Mutant p53 Reactivator, Induces Apoptosis and Enhances Chemotherapeutic Cytotoxicity in Pancreatic Cancer Cell Lines’. Investigational New Drugs 32, no. 5 (October 2014): 783–94. https://www.ncbi.nlm.nih.gov/pubmed/24838627

Izetti, Patricia, Agnes Hautefeuille, Ana Lucia Abujamra, Caroline Brunetto de Farias, Juliana Giacomazzi, Bárbara Alemar, Guido Lenz, et al. ‘PRIMA-1, a Mutant p53 Reactivator, Induces Apoptosis and Enhances Chemotherapeutic Cytotoxicity in Pancreatic Cancer Cell Lines’. Investigational New Drugs 32, no. 5 (October 2014): 783–94

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

p53 mutation – Li-Fraumeni Syndrome – Likelihood of Genetic or Hereditary conditions playing a role in Intergenerational incidence of Cancer

Reporter: Aviva Lev-Ari, PhD, RN

https://pharmaceuticalintelligence.com/2016/12/01/p53-mutation-li-fraumeni-syndrome-likelihood-of-genetic-or-hereditary-conditions-playing-a-role-in-intergenerational-incidence-of-cancer/

Pancreatic Cancer: Articles of Note @PharmaceuticalIntelligence.com

Curator: Aviva Lev-Ari, PhD, RN

https://pharmaceuticalintelligence.com/2016/05/26/pancreatic-cancer-articles-of-note-pharmaceuticalintelligence-com/

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

 

MicroRNAs (miRNAs) are a group of small non-coding RNA molecules that play a major role in posttranscriptional regulation of gene expression and are expressed in an organ-specific manner. One miRNA can potentially regulate the expression of several genes, depending on cell type and differentiation stage. They control every cellular process and their altered regulation is involved in human diseases. miRNAs are differentially expressed in the male and female gonads and have an organ-specific reproductive function. Exerting their affect through germ cells and gonadal somatic cells, miRNAs regulate key proteins necessary for gonad development. The role of miRNAs in the testes is only starting to emerge though they have been shown to be required for adequate spermatogenesis. In the ovary, miRNAs play a fundamental role in follicles’ assembly, growth, differentiation, and ovulation.

 

Deciphering the underlying causes of idiopathic male infertility is one of the main challenges in reproductive medicine. This is especially relevant in infertile patients displaying normal seminal parameters and no urogenital or genetic abnormalities. In these cases, the search for additional sperm biomarkers is of high interest. This study was aimed to determine the implications of the sperm miRNA expression profiles in the reproductive capacity of normozoospermic infertile individuals. The expression levels of 736 miRNAs were evaluated in spermatozoa from normozoospermic infertile males and normozoospermic fertile males analyzed under the same conditions. 57 miRNAs were differentially expressed between populations; 20 of them was regulated by a host gene promoter that in three cases comprised genes involved in fertility. The predicted targets of the differentially expressed miRNAs unveiled a significant enrichment of biological processes related to embryonic morphogenesis and chromatin modification. Normozoospermic infertile individuals exhibit a specific sperm miRNA expression profile clearly differentiated from normozoospermic fertile individuals. This miRNA cargo has potential implications in the individuals’ reproductive competence.

 

Circulating or “extracellular” miRNAs detected in biological fluids, could be used as potential diagnostic and prognostic biomarkers of several disease, such as cancer, gynecological and pregnancy disorders. However, their contributions in female infertility and in vitro fertilization (IVF) remain unknown. Polycystic ovary syndrome (PCOS) is a frequent endocrine disorder in women. PCOS is associated with altered features of androgen metabolism, increased insulin resistance and impaired fertility. Furthermore, PCOS, being a syndrome diagnosis, is heterogeneous and characterized by polycystic ovaries, chronic anovulation and evidence of hyperandrogenism, as well as being associated with chronic low-grade inflammation and an increased life time risk of type 2 diabetes. Altered miRNA levels have been associated with diabetes, insulin resistance, inflammation and various cancers. Studies have shown that circulating miRNAs are present in whole blood, serum, plasma and the follicular fluid of PCOS patients and that these might serve as potential biomarkers and a new approach for the diagnosis of PCOS. Presence of miRNA in mammalian follicular fluid has been demonstrated to be enclosed within microvesicles and exosomes or they can also be associated to protein complexes. The presence of microvesicles and exosomes carrying microRNAs in follicular fluid could represent an alternative mechanism of autocrine and paracrine communication inside the ovarian follicle. The investigation of the expression profiles of five circulating miRNAs (let-7b, miR-29a, miR-30a, miR-140 and miR-320a) in human follicular fluid from women with normal ovarian reserve and with polycystic ovary syndrome (PCOS) and their ability to predict IVF outcomes showed that these miRNAs could provide new helpful biomarkers to facilitate personalized medical care for oocyte quality in ART (Assisted Reproductive Treatment) and during IVF (In Vitro Fertilization).

 

References:

 

http://link.springer.com/chapter/10.1007%2F978-3-319-31973-5_12

 

http://onlinelibrary.wiley.com/doi/10.1111/andr.12276/abstract;jsessionid=F805A89DCC94BDBD42D6D60C40AD4AB0.f03t03

 

http://www.sciencedirect.com/science/article/pii/S0009279716302241

 

http://link.springer.com/article/10.1007%2Fs10815-016-0657-9

 

http://www.nature.com/articles/srep24976

 

 

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

 

Mitochondrial disease

 

Mitochondria are present in almost all human cells, and vary in number from a few tens to many thousands. They generate the majority of a cell’s energy supply which powers every part of our body. Mitochondria have their own separate DNA, which carries just a few genes. All of these genes are involved in energy production but determine no other characteristics. And so, any faults in these genes lead only to problems in energy production. Around 1 in 6500 children is thought to be born with a serious mitochondrial disorder due to faults in mitochondrial DNA.

 

Unlike nuclear genes, mitochondrial DNA is inherited only from our mothers. Mothers can carry abnormal mitochondria and be at risk of passing on serious disease to their children, even if they themselves show only mild or no symptoms. It is for such women who by chance have a high proportion of faulty mitochondrial DNA in their eggs for which the methods of mitochondrial replacement or “donation” have been developed. This technique is also referred as the three parent technique and it involves a couple and a donor.

 

Mitochondrial Donation

 

The most developed techniques, maternal spindle transfer (MST) and pro-nuclear transfer (PNT), are based on an IVF cycle but have additional steps. Other techniques are being developed.

 

In both MST and PNT, nuclear DNA is moved from a patient’s egg or embryo containing unhealthy mitochondria to a donor’s egg or embryo containing healthy mitochondria, from which the donor’s nuclear DNA has been removed.

 

mst

Maternal spindle transfer Bredenoord, A and P. Braude (2010) “Ethics of mitochondrial gene replacement: from bench to bedside” BMJ 341.

 

pnt

Pronuclear transfer Bredenoord, A and P. Braude (2010) “Ethics of mitochondrial gene replacement: from bench to bedside” BMJ 341.

 

Research Carried Out and Safety Issues

 

There have been many experiments conducted using MST and PNT in animals. PNT has been carried out since the mid-1980s in mice. MST has been carried out in a wide range of animals. More recently mice, monkeys and human embryos have been created with the specific aim of developing MST and PNT for avoiding mitochondrial disease.

 

  • There is no evidence to show that mitochondrial donation is unsafe
  • Research is progressing well and the recommended further experiments are expected to confirm this view.

 

The main area of research needed is to observe cells derived from embryos created by MST and PNT, to see how mitochondria behave.

 

Concerns about Mitochondrial Donation

 

The scientific evidence raises some potential concerns about mitochondrial donation. Just as we all have different blood groups, we also have different types of mitochondria, called haplotypes. Some scientists have suggested that if the patient and the mitochondria donor have different mitochondrial haplotypes, there is a theoretical risk that the donor’s mitochondria won’t be able to ‘talk’ properly to the patient’s nuclear DNA, which could cause problems in the embryo and resulting child. So, mitochondria haplotype matching in the process of selecting donors may be done to avoid problems.

 

Another potential concern is that a small amount of unhealthy mitochondrial DNA may be transferred into the donor’s egg along with the mother’s nuclear DNA. Studies carried out on MST and PNT show that some so-called mitochondrial ‘carry-over’ occurs. However, the carry-over is lower than 2% of the mitochondria in the resulting embryo, an amount which is very unlikely to be problematic for the children born.

 

References:

 

http://mitochondria.hfea.gov.uk/mitochondria/what-is-mitochondrial-disease/

 

http://mitochondria.hfea.gov.uk/mitochondria/what-is-mitochondrial-disease/new-techniques-to-prevent-mitochondrial-disease/

 

https://www.newscientist.com/article/2107219-exclusive-worlds-first-baby-born-with-new-3-parent-technique/

 

https://www.newscientist.com/article/2108549-exclusive-3-parent-baby-method-already-used-for-infertility/

 

http://www.frontlinegenomics.com/news/7889/ethical-concerns-raised-first-three-parent-ivf-baby/

 

http://www.hfea.gov.uk/docs/2011-04-18_Mitochondria_review_-_final_report.PDF

 

http://www.hfea.gov.uk/docs/Mito-Annex_VIII-science_review_update.pdf

 

http://www.hfea.gov.uk/docs/Third_Mitochondrial_replacement_scientific_review.pdf

 

https://pharmaceuticalintelligence.com/2014/02/26/three-parent-baby-making-practice-of-modifying-oocytes-for-use-in-in-vitro-fertilization-fda-hearing/

 

 

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