Health
Growing eggs and sperm to treat infertility – News-Medical.net
Scientists at the University of California, Los Angeles, have reported, in the journal Cell Reports, the mechanism of how the very early precursor or stem cells which eventually give rise to the germ cells, eggs and sperm, are formed over the course of development. This could help create eggs and sperms under laboratory conditions to help infertile people who don’t have sperms, or eggs, for instance.
The problem
Infertility is a problem for 1 in 10 of the population in the US, and shows an increasing trend over the last few decades because of the later time of first pregnancy. In many of these cases, in vitro fertilization (IVF), and more advanced techniques like intracytoplasmic sperm injection (ICSI) are successfully used to begin a pregnancy. In IVF, the male and female germ cells are joined outside the body and the resulting conceptus is later inserted back into the uterus. With ICSI, the sperm nucleus is injected directly into the egg cell.
However, both of these techniques require sperm and eggs to be present. When it comes to people who lack these germ cells, other therapies must be looked for. The lack of sperm or eggs could be a result of genetic abnormalities, chemotherapy or radiation, or sometimes unknown causes.
One option is to use donor eggs or sperm, or both. However, as researcher Amander Clark says, “With donated eggs and sperm, the child is not genetically related to one or both parents. What we want to do is use stem cells to be able to generate germ cells outside the human body so that this kind of infertility can be overcome.”
The beginning
All embryos develop from a set of undifferentiated cells are present that is capable of developing in many different directions to make almost any kind of cell in the body. These are the pluripotent stem cells, the cells that can also give rise to sperms and eggs.
Scientists have already discovered how to make cells very similar to these from already differentiated adult skin or blood cells, by reversing the developmental timetable and un-differentiating them. These are called induced pluripotent stem cells (iPSCs).
The process
The current study made use of technology to measure the genes that were active in over 100,000 embryonic stem cells and iPSCs as they gave rise to sperm and egg cells. This huge amount of information was then analyzed, using newly developed algorithms from their colleagues at the Massachusetts Institute of Technology, to discern the pattern of development.
The scientists were thus able to come up with a high-definition picture of the process by which germ cells are formed. The first step occurred at 24-48 hours, when the stem cells begin to differentiate into the different types of cells that continue to develop into all the distinctive and highly specialized cells of the adult human body.
At the 12th day after fertilization, around the time of implantation but before the earliest formation of embryonic parts like the primitive streak or the gastrula, it is possible to recognize the earliest stem cells that are differentiating into the germ cell production line, called the human primordial germ cells (hPGCs). At this point the hPGC-like cells (hPGCLCs) are specified, or set apart, by a change in their gene expression towards a transitional state. At this point they share the characteristics of the pre-implantation stem cell as well as the post-implantation embryonic stem cell, which is described as naïve and primed, respectively. They then turn into the pathway to become germ cell progenitors, by the regulation of the sex-determining chromosome area SOX17 that is responsible for hPGCLC specification.
At this point, the hPGCLCs can no longer differentiate into somatic cells – this is called crossing Weismann’s barrier, after the legendary German biologist who proposed the existence of the hereditary factor within germ cells, today known to be DNA. This is the key point in achieving the in vitro production of gametes, or sex cells (eggs and sperms).
Implications
In the current experiment, the primed hPGCLCs are turned back to become transitional germinal pluripotent cells and thus begin to differentiate into germ cells. The researchers now know when to intervene so that they can maximize the number of germ cells formed by diverting more of the differentiation process into this stream.
Another interesting finding was that germ cells arise from stem cells originating in the amnion, the thin translucent membrane containing the fluid surrounding the embryo, as well as the gastrula-forming cells that belong to the baby proper.
Finally, they found that the gene activation patterns leading to germ cell formation are nearly the same, whether it is an embryonic stem cell or an iPSC. This proves they are using the right technique to form the germ cells.
Clark says, “Now we’re poised to take the next step of combining these cells with ovary or testis cells.” These germ cells are not yet decided on whether to develop into sperm or egg cells, and this depends on the molecular signals they receive, whether from the ovary or the testis.
The researchers say, “Through this work, we uncovered the human germline trajectory and discovered the identity of potential peri-implantation progenitors for hPGCs.”
The researchers hope they will eventually be able to coax the iPSCs formed from the patient’s own skin cells to differentiate into germ cells and into ovarian or testicular tissue. This could be used to let each person have his or her germ cells created in the laboratory. The process, however, is a long-drawn-out one and will require intensive research and work.
A step too far?
These techniques have been restricted to laboratory use, and are not approved by the US Food and Drug Administration for use in humans, nor have they undergone human testing.
It is obvious that such experiments involve the abundant use of human pre-implantation embryos. Though ethical approval norms are fulfilled, such testing nonetheless raises numerous other ethical issues. Again, the true motivation of the research remains in doubt since the lack of value for potential human life shown by such experiments makes it difficult to believe that making it possible for infertile couples to have babies is the real incentive.
Finally, the potential for misapplication of this technology is obvious, just one example being its use to allow both sperm and egg cells to be created from the same patient, nurtured by both ovarian and testicular tissue derived from that patient, and eventually giving rise to a single-parent zygote. One hopes that scientists will not allow their curiosity to run rampant but rein it in within appropriate bounds rather than ruin human life with unnecessary technology -simply because they can.
UCLA research could be step toward lab-grown eggs and sperm to treat infertility – http://newsroom.ucla.edu/releases/lab-grown-eggs-and-sperm-step-toward-infertility-treatment
Human Primordial Germ Cells Are Specified from Lineage-Primed Progenitors Chen, Di et al. Cell Reports, Volume 29, Issue 13, 4568 – 4582.e5, https://www.cell.com/cell-reports/fulltext/S2211-1247(19)31574-8
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NEWS RELEASE
SOUTHLAKE REGIONAL HEALTH CENTRE
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This Cancer Awareness Month, Southlake is adding advanced technologies to detect and treat breast cancer and other women’s cancers thanks to generous community donor support, most recently through the HERE is Where Cancer Meets its Match campaign. New cancer care technology, including new mammography machines, the MyoSure System and the MOLLI 2® System will make a measurable impact in diagnosing and treating women’s cancers in the communities Southlake serves.
Southlake is installing three new mammography machines to expand its breast cancer screening program to 1,500 more women each year. Two of these machines have new biopsy capabilities that will reduce the number of cancelled exams due to equipment failure, ensuring timely care for women. Women ages 40 to 49 years old will be able to self-refer for publicly funded mammograms through the Ontario Breast Screening Program starting this fall.
“Early detection is critical when treating breast cancer and other women’s cancers,” said Lorrie Reynolds, Director, Regional Cancer Program at Southlake. “We treat more than 1,700 breast cancer patients at Southlake every year. By adding advanced technology, like the new mammography machines, we’re ensuring women have the best experience at Southlake.”
Southlake is also introducing the MyoSure System, an innovative technology that can help detect female reproductive cancers. Damaged tissue in a woman’s uterus such as fibroids and polyps can now be removed in a precise, minimally invasive procedure that leaves the rest of the uterus intact. This will improve the overall patient experience by supporting faster recovery, reducing the risk of infection and giving more women the option to have children. An estimated 200 women per year will benefit from the MyoSure System.
The new mammography machines and the MyoSure System build on Southlake’s recent investment in the MOLLI 2® System, a made-in-Canada wire-free breast localization technology. This technology is considerably less invasive and more accurate when compared to wire-guided localization, resulting in a better patient experience and improved cosmetic outcomes. More than 200 women each year will benefit from this innovative medical device as they are treated for breast cancer at Southlake.
“As a clinician caring for women with cancer in our community, I’m incredibly proud of the work Southlake is doing to advance women’s health and improve patient experiences,” said Sara Temple, MD, Surgical Oncologist and Chief of Surgery at Southlake. “Women who visit Southlake can be confident that they are receiving leading edge care, close to home when they need it most.”
The World Health Organization anticipates a 77 per cent increase in cancer diagnoses by 2050. Southlake serves some of the fastest growing communities in Canada and anticipates that the number of patients requiring cancer care will grow. By investing in new technology, Southlake is ensuring that women in the communities it serves have access to leading edge cancer care. All of these investments were funded with support from community donors who generously gave to Southlake to support investments into women’s health at the hospital.
“The generosity of our donor community and the impact they have made for women receiving cancer diagnosis and treatment at Southlake is something we can all take great pride in,” said Jennifer Ritter, President and CEO of Southlake Foundation. “From our Women’s Health Initiative donors supporting new mammography machines, to the Ladies in Philanthropy for Southlake funding the MOLLI 2 System, to our long-standing partners The Edge Benefits and Pheasant Run Golf Club enabling the introduction of MyoSure System through their joint annual charity golf tournament, we are incredibly lucky to share a vision of access to exceptional care for everyone who depends on Southlake when they need us most. Thank you, to every donor who contributed to these important upgrades to care for women.”
Southlake Foundation’s HERE is Where Cancer Meets its Match campaign supports the Stronach Regional Cancer Centre at Southlake. For more information or to make a donation, visit: southlake.ca/HERE.
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The U.S. Food and Drug Administration says that samples of pasteurized milk have tested positive for remnants of the bird flu virus that has infected dairy cows.
The agency stressed that the material is inactivated and that the findings “do not represent actual virus that may be a risk to consumers.” Officials added that they’re continuing to study the issue.
“To date, we have seen nothing that would change our assessment that the commercial milk supply is safe,” the FDA said in a statement on Tuesday.
The announcement comes nearly a month after an avian influenza virus that has sickened millions of wild and commercial birds in recent years was detected in dairy cows in at least eight states. The Agriculture Department (USDA) says 33 herds have been affected to date.
FDA officials didn’t indicate how many samples they tested or where they were obtained. The agency has been evaluating milk during processing and from grocery stores, officials said. Results of additional tests are expected in “the next few days to weeks.”
WATCH | Bird flu spread in U.S. cows:
For the first time ever, avian influenza, or H5N1 bird flu, was detected in roughly a dozen dairy cow herds across the U.S. About That producer Lauren Bird explores why scientists and public health officials are concerned about the cross-species transmission and whether humans are now at higher risk.
The polymerase chain reaction (PCR) lab test the FDA used would have detected viral genetic material even after live virus was killed by pasteurization, or heat treatment, said Lee-Ann Jaykus, an emeritus food microbiologist and virologist at North Carolina State University
“There is no evidence to date that this is infectious virus, and the FDA is following up on that,” Jaykus said.
Officials with the FDA and the USDA had previously said milk from affected cattle did not enter the commercial supply. Milk from sick animals is supposed to be diverted and destroyed. Federal regulations require milk that enters interstate commerce to be pasteurized.
Tests for viable virus underway, agency says
Because the detection of the bird flu virus known as Type A H5N1 in dairy cattle is new and the situation is evolving, no studies on the effects of pasteurization on the virus have been completed, FDA officials said. But past research shows that pasteurization is “very likely” to inactivate heat-sensitive viruses like H5N1, the agency added.
The agency said it has been evaluating milk from affected animals, in the processing system and on the shelves. It said it is completing a large, representative national sample to understand the extent of the findings.
Matt Herrick, a spokesperson for the International Dairy Foods Association, said that time and temperature regulations for pasteurization ensure that the commercial U.S. milk supply is safe. Remnants of the virus “have zero impact on human health,” he wrote in an email.
Scientists confirmed the H5N1 virus in dairy cows in March after weeks of reports that cows in Texas were suffering from a mysterious malady. The cows were lethargic and saw a dramatic reduction in milk production. Although the H5N1 virus is lethal to commercial poultry, most infected cattle seem to recover within two weeks, experts said.
To date, two people in the U.S. have been infected with bird flu. A Texas dairy worker who was in close contact with an infected cow recently developed a mild eye infection and has recovered. In 2022, a prison inmate in a work program caught it while killing infected birds at a Colorado poultry farm. His only symptom was fatigue, and he recovered.
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The U.S. Food and Drug Administration said Tuesday that samples of pasteurized milk had tested positive for remnants of the bird flu virus that has infected dairy cows.
The agency stressed that the material is inactivated and that the findings “do not represent actual virus that may be a risk to consumers.” Officials added that they’re continuing to study the issue.
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