Sperm

Lifelong production of sperm is made possible by a newly discovered stem cell regulator.According to research conducted by the University of Pennsylvania, the enzyme DOT1L, a stem cell self-renewal factor, is necessary for mice to continue producing sperm throughout adulthood.Men may continue to generate sperm throughout their adult life, in contrast to women who are born with all the eggs they will ever have. To do so, they must constantly renew the spermatogonial stem cells that give birth to sperm.According to research…

Natural and synthetic embryos side by side show comparable brain and heart formation. Credit: Amadei and HandfordScientists from the University of Cambridge have created model embryos from mouse stem cells that form a brain, a beating heart, and the foundations of all the other organs of the body. It represents a new avenue for recreating the first stages of life.The team of researchers, led by Professor Magdalena Zernicka-Goetz, developed the embryo model without eggs or sperm. Instead, they used stem cells – the body’s…

The recipe for mammalian life is simple: take an egg, add sperm and wait. But two new papers demonstrate that there’s another way. Under the right conditions, stem cells can divide and self-organize into an embryo on their own. In studies published in Cell and Nature this month, two groups report that they have grown synthetic mouse embryos for longer than ever before. The embryos grew for 8.5 days, long enough for them to develop distinct organs — a beating heart, a gut tube and even neural folds. The process is far…

A comparison of a natural (top) and synthetic (bottom) mouse embryo, which shows similar brain and heart formation. Photo: Amadei and HandfordScientists in the UK say they’ve pulled off a feat of genetic engineering: creating a “synthetic” mouse embryo without the need for egg or sperm cells. The embryos were created with stem cells instead and were able to begin developing a brain, heart, and other organs for up to a week. The researchers believe that their work may one day help answer why many pregnancies in humans fail…

Laura High’s hormones have been out of whack since she was as young as 13 years old. Her period was “all over the place,” so her doctors put her on birth control, but the hormonal issues continued to plague her. As she got older, things only became worse; she was gaining weight quickly and easily, and her anxiety was through the roof. “I could tell something was wrong,” says High, who is 34 years old and works as a stand-up comedian in New York City.But getting to the bottom of the problem was complicated—since High only…

But there are other hurdles—some so challenging that many scientists have given up. For one thing, nudging the stem cells in the right direction requires, it seems, a unique touch and expertise. Not just anyone will be able to make egg and sperm cells in the lab, says Saitou.  Top chef Saitou and Hayashi, now at Kyushu University, lead world-renowned teams of extraordinary skill. Their achievements might not have been possible without the contributions of Hiroshi Ohta, for example. Ohta is an expert in anesthetizing…

Cue the Jurassic Park theme song: Scientists in Switzerland appear to have pulled off a remarkable feat, creating sterile and seemingly healthy mice that can produce the sperm cells of a rat. These rodent chimeras weren’t able to make viable rat offspring, but the work could lead to a new method of preserving species on the brink of extinction, the team says.Scientists routinely modify the genetics of animals in the lab to conduct various experiments, even to the point of breeding mice with cells or organs that closely…

Researchers have created synthetic mouse embryos out of stem cells, removing the need for sperm, eggs and even a womb. They were then grown to almost half the entire gestation period, at which point they had all of the organ progenitors, including a beating heart. The tech could eventually be used to grow organs for transplant.The new study, from researchers at the Weizmann Institute of Science in Israel, built on two branches of the team’s previous research. The first involved reprogramming stem cells into a “naive”…

By University of Copenhagen - The Faculty of Health and Medical Sciences June 29, 2022After 8 weeks of losing weight, patients increased sperm concentration by 50 percent and the sperm count by 40 percent. After a year, the men had twice as many sperm cells as before their weight loss.Obese men can double their sperm countMen all throughout the globe are experiencing declining semen quality, which is commonly referred to as an outright fertility crisis.However, there may be some good news for some of the males who are…

Left: Normal spermatogenesis in the scrotum (34°C) Right: Impaired spermatogenesis in the abdomen (38°C). Credit: NIBBTesticles of most mammals are cooled in the scrotum, and elevated testicular temperatures lead to spermatogenesis failure and male infertility. A team of researchers led by Shosei Yoshida at the National Institute for Basic Biology in Japan detailed this process using organ cultures and revealed that spermatogenesis is impaired at multiple steps in a delicate temperature-dependent manner.Spermatogenesis is…