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Posts Tagged ‘infertility’


Embryo Stem Cells Out of Skin

Reporter: Irina Robu, PhD

Researchers at Hebrew University identified a set of genes able to transform murine skin cells into three cell types such as the embryo itself, the placenta and extraembryonic tissue i.e. umbilical cord which was published in the journal Cell Stem Cell.

Dr. Oren Ram, Institute of Life Science at Hebrew University, Prof. Tommy Kaplan, School of Computer Science and Engineering found a new combination of five genes that once inserted into skin cells, reprogram the cells into each of three early embryonic cell types. Researchers identified that the gene “Eomes” pushes the cell toward placental stem-cell identity and placental development, whereas the “Esrrb” gene arranges fetus stem cells development through the temporary procurement of an extraembryonic stem cell identity.The team used this to examine the molecular forces that oversee cell fate decisions for skin cell reprogramming and the natural process of embryonic development.

Even though this groundbreaking research could provide a path toward creating entire human embryos from human cell skin cells without need for sperm of organs, that is still a long way in the future. However, for now this work can have large implications for modeling embryonic disease and placental dysfunctions in addition to solving infertility problems by creating human embryos in a petri dish.

SOURCE
https://www.jpost.com/OMG/A-baby-from-skin-cells-Israeli-team-makes-embryo-stem-cells-out-of-skin-588531

 

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

 

Anti-Müllerian Hormone (AMH), is secreted by growing follicles that contains the egg or ovum. According to regular practice low AMH and high Follicle Stimulating Hormone (FSH) are generally considered as indicators of diminished egg quantity in a female. But, there are several cases the female conceived absolutely normally without any support even after low AMH was reported.

 

Therefore, a new research published in the Journal of the American Medical Association declares that AMH doesn’t dictate a woman’s reproductive potential. Although AMH testing is one of the most common ways that doctors assess a woman’s fertility. Present research says that all it takes is one egg each cycle and AMH is not a marker of whether a female can or cannot become pregnant. So, for women who haven’t yet tried to get pregnant and who are wondering whether they are fertile, an AMH value isn’t going to be helpful in that context. In addition, AMH is not necessarily a good marker to predict that whether one has to cryopreserve her eggs. So, practically doctors don’t yet have a way to definitively predict egg quality or a woman’s long-term ability to conceive, but age is obviously one of the most important factors.

 

The above mentioned study followed 750 women between the ages of 30 and 44 who had been trying to conceive for three months or less. During the 12-month observation period, those with low AMH values of less than 0.7 were not less likely to conceive than those who had normal AMH values. The study had various limitations, however, that are worth noting. The researchers only included women who did not have a history of infertility. Women who sought fertility treatments (about 6 percent) were withdrawn. And only 12 percent of the women were in the 38-to-44 age range. In addition, the number of live births was unavailable.

 

Among women aged 30 to 44 years without a history of infertility who had been trying to conceive for 3 months or less, biomarkers indicating diminished ovarian reserve compared with normal ovarian reserve were not associated with reduced fertility. These findings do not support the use of urinary or blood FSH tests or AMH levels to assess natural fertility for women with these characteristics. The researchers’ next want to see whether low AMH is associated with a higher risk of miscarriage among the women who conceived.

 

Although AMH testing isn’t designed to be an overall gauge of a woman’s fertility, it can still provide valuable information, especially for women who are infertile and seeking treatment. It can assist in diagnosing polycystic ovarian syndrome, and identify when a woman is getting closer to menopause. Previous research also showed that AMH is good predictor of a woman’s response to ovarian stimulation for in vitro fertilization and therefore it can predict the probability of conceiving via in vitro fertilization (I.V.F.).

 

References:

 

https://jamanetwork.com/journals/jama/article-abstract/2656811?JamaNetworkReader=True

 

https://www.nytimes.com/2017/10/16/health/fertility-test-ovarian-reserve.html

 

https://academic.oup.com/humrep/article/26/11/2925/656065

 

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3339896/

 

https://www.ncbi.nlm.nih.gov/pubmed/27179263

 

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Cellular switch molecule for sperm motility control: a novel target for male contraception and infertility treatments

Reporter and Curator: Sudipta Saha, Ph.D.

 

Researchers have discovered the cellular switch that boosts the activity of sperm cells so that they can travel to the egg.  The finding may lead to new options for male contraception as well as treatments for infertility resulting from problems with sperm mobility.

Inside the male reproductive tract, mature sperm are capable of limited movement. This limited movement, however, is not enough to propel them toward the egg when they enter the female reproductive tract. To begin their journey, they must first be activated by the hormone progesterone, which is released by the egg.

The researchers reported that the molecule to which progesterone must bind is the enzyme alpha/beta hydrolase domain containing protein 2 (ABHD2), found in the sperm cell’s outer membrane. Similarly, strategies to bypass or enhance the enzyme might provide therapies for treating infertility resulting from sperm that lack movement capability.

Before a sperm can transition to the hyper-active phase, calcium must pass through the cell’s outer membrane and enter the flagella, the tail-like appendage the cell uses to propel itself. The sperm protein known as CatSper joins with similar proteins in the flagella to allow the entry of calcium.

When the researchers undertook the current study, it was not known whether progesterone interacted directly with CatSper to trigger the calcium influx, or acted on some other molecule (which, in turn, acted on CatSper). Before treating sperm with progesterone, the researchers exposed them to a chemical that inhibits a particular class of enzymes that they believed could include the candidate molecule that acted on CatSper. The hunch proved correct: the treated cells remained inactive after progesterone exposure, indicating that CatSper was not directly involved.

Working with modified progesterone, the researchers eventually isolated ABHD2 from the sperm tails. When the researchers inactivated ABHD2, exposure to progesterone failed to activate the sperm cells, confirming that ABHD2 is the molecular target for progesterone.

All of the technical terminology aside, this means that the researchers have pinned down the cellular switch that boosts the sperm along to the egg, so by blocking the ABHD2 activity, new male birth control methods could be on the way. Conversely, enhancing the enzyme could lead to new treatments for male infertility.

It will be interesting to see how this discovery impacts future research concerning male birth control and infertility treatments. Perhaps it’s the missing piece of information that will quickly yield an effective new male contraception option.

 

SOURCES

http://www.nih.gov/news-events/news-releases/researchers-identify-molecule-needed-sperm-activation

http://www.ncbi.nlm.nih.gov/pubmed/26989199

http://thescienceexplorer.com/brain-and-body/nih-funded-study-made-breakthrough-discovery-could-lead-new-male-birth-control

http://www.jhunewsletter.com/2016/03/31/researchers-find-a-protein-fertilization-catalyst/

 

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

 

An estimated 10 to 15% of couples suffer from infertility, and many treatment decisions rely on trial and error. A team of international scientists has found a common genetic variant which may explain why some men with normal sperm counts and good quality sperm are affected by infertility.

The study findings suggested that men with a variation in a gene which codes for a sperm-coating protein called beta defensin 126 (DEFB126) have a reduction in the protein coat on the outside of the sperm which makes it difficult for the sperm to ‘swim’ to the egg.

Dr Edward Hollox of the University of Leicester and co-author of the study said: ‘If you’ve got this gene variant you should allow that little bit longer if your partner’s planning to get pregnant’. The researchers, including scientists from the University of California and the Anhui Medical University in China, carried out the study on over 500 newly-wed Chinese couples who were trying for a baby.

They found that when men’s sperm lacked a coat of the DEFB126 protein, their wives were significantly less likely than expected to become pregnant.

Previous studies have shown that two copies of the genetic variant may be found in up to one quarter of men around the world, with about half of all men having one copy. The DEFB126 protein coat helps sperm to swim through cervical mucus and evade the woman’s immune system, as well as enabling it to attach to the walls of fallopian tubes.

The study showed, however, that men with two copies of the variant produced sperm that were less able to swim through a substitute to cervical mucus, hyaluronic acid gel. In macaques, it has already been shown that this protein is important in evading the immune system and the researchers believe the protein coat plays the same role in humans. Commenting on the study, Dr Allan Pacey, senior lecturer in Andrology at the University of Sheffield, said: ‘We actually understand very little about the subtle molecular events which occur in sperm as they make their journey through the woman’s body to fertilise an egg’. The research was published in the journal Science Translational Medicine. If replicated in future studies, these findings promise to guide choices about the timing and type of assisted reproduction interventions—and further hint at the possibility of treating sperm from del/del homozygotes to promote fertility.

A gene which helps sperm bind to an egg has been identified by scientists. Sperm-to-egg binding is an essential process during fertilization and although the preliminary studies were performed on mice, the gene may represent a new target for infertility treatments. Sperm from mice that had the gene switched off were only able to fertilise eggs from female mice three percent of the time compared to 80 percent fertilisation success in normal mice.

The gene codes for a protein called PDILT which helps another gene product to form and assemble correctly and then to reach the surface of a sperm. Once this happens the sperm is able to navigate the uterus and oviduct and penetrate the sticky outer layers of an egg. The study, which is published in PNAS (Proceedings of the National Academy of Sciences), also demonstrates the importance of cumulus cells, a cluster of cells that surround and protect the egg, as their presence allows sperm to bind to their target. Sperm from mice that had their PDILT gene switched off would not bind to a bare egg, but would bind to an egg surrounded by cumulus cells.

Co-author Dr Adam Benham from Durham University in the UK said that the PDILT protein is ‘an essential part of the navigation system of sperm. Like any navigation system, you have to programme where it is that you want to go and this protein plays an essential role in getting sperm to the right destination, in good shape, and in good time’. A question now for the scientists is whether the PDILT gene has as much importance in human fertility as it does in mice. ‘Mutations in the gene may be responsible for unexplained male fertility problems and further research may aid more effective IVF treatment‘, said Dr Benham.

Source References:

http://stm.sciencemag.org/content/3/92/92ps31.abstract

http://www.bionews.org.uk/page_142955.asp

http://www.itv.com/news/update/2012-05-01/scientists-discover-new-gene-key-to-fertility/

http://www.bionews.org.uk/page_102705.asp

 

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Reporter: Sudipta Saha, Ph.D.

Laboratory testing is an integral component of the evaluation of the infertile men. This testing must be appropriate and specific for the individual couple. As there are many tests that evaluate various aspects of infertility, the urologist have to decide what information the tests can offer as well as the limitations of each assay. The semen analysis remains the cornerstone of the evaluation but is not a functional assay. Other assays such as sperm-cervical mucus tests, hemizona assays, and the sperm-penetration assay are functional tests. Through the appropriate use of these and other tests, the urologist will be capable of better and more accurately counseling the infertile couple (http://www.springerlink.com/content/t518435632851834/).

5.3 million American couples of reproductive age (9%) are affected by infertility, among which male factors account for up to 50% of cases, which necessitates the identification of parameters defining sperm quality, including sperm count and motility. In vitro fertilization (IVF) with or without intra cytoplasmic sperm injection (ICSI) has become the most widely used assisted reproductive technology (ART) in modern clinical practice to overcome male infertility challenges. One of the obstacles of IVF and ICSI lies in identifying and isolating the most motile and presumably healthiest sperm from semen samples that have low sperm counts (oligozoospermia) and/or low sperm motility (oligospermaesthenia). Microfluidic systems have shown potential to sort sperm with flow systems. However, the small field of view (FOV) of conventional microscopes commonly used to image sperm motion presents challenges in tracking a large number of sperm cells simultaneously. To address this challenge, Zhang et. al. at Harvard Medical School and MIT integrated a lensless charge-coupled device (CCD) with a microfluidic chip to enable wide FOV and automatic recording as the sperm move inside a microfluidic channel. The integrated system enables the sorting and tracking of a population of sperm that have been placed in a microfluidic channel. This channel can be monitored in both horizontal and vertical configuration similar to a swim up column method used clinically. Sperm motilities can be quantified by tracing the shadow paths for individual sperm. Moreover, as the sperm are sorted by swimming from the inlet towards the outlet of a microfluidic channel, motile sperm that reach the outlet can be extracted from the channel at the end of the process. This technology can lead to methods to evaluate each sperm individually in terms of motility response in a wide field of view, which could prove especially useful, when working with oligozoospermic or oligospermaesthenic samples, in which the most motile sperm need to be isolated from a pool of small number of sperm (http://mit.edu/bammlabs/Lensless_Imaging.pdf).

There are also some new kit based methods developed to analyze male fertility at home. There is no need to count hundreds of sperm in these methods. They are user-friendly, quite affordable (between 40 and 100 dollars) and quick. One of the pioneers on the market is FertilMARQ Home Diagnostic Screening Test, which works by staining the cells in the sperm sample to produce a color. The intensity of this color is then compared to a color reference on the FertilMARQ test cassette providing results with an overall accuracy of 78 percent. Another popular home kit is Spermcheck fertility, known to be 97 percent accurate. This test is based on the detection of SP-10, a protein compound found on the surface of the head of a sperm cell and which concentrations are directly related to the sperm count number (http://howto.wired.com/wiki/Check_a_Man’s_Sperm_Count).

Techniques such as Vasectomy Reversal and Tubal Ligation Reversal, In vitro fertilization (IVF), Intra-cytoplasmic sperm injection (ICSI) have also improved with respect to the instrumentation used. Dr. Sherman J. Silber, M.D. and his Japanese collaborators have recently developed a new “mini-IVF” technique that saves money, eliminates complications of IVF, and is useful for older women and women with low ovarian reserve. (http://www.infertile.com/).

The pioneer company in making the most sophisticated and most popular sperm analysis instrument is Hamilton Thorne (http://www.hamiltonthorne.com/products/casa/systems-index.htm) and their website may be reviewed for more knowledge on modern sperm analysis.

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