Treatments for childhood cancers are increasingly successful with cure rates approaching 80%, but success often comes with a downside for the surviving men: the cancer treatments they received as boys can leave them sterile as adults. Now, a research team led by Ralph Brinster of the University of Pennsylvania School of Veterinary Medicine has completed a 14-year experiment that gives hope for a technique that could restore their fertility. Brinster is the Richard King Mellon Professor of Reproductive Physiology at Penn Vet and was recently awarded the National Medal of Science for his lifetime of research on the genetics of the mammalian germline, the cells that give rise to sperm and eggs. In his most recent research, Brinster collaborated with fellow members of the Department of Animal Biology at Penn Vet, with members of the Department of Cell and Developmental Biology at Penn's Perelman School of Medicine and with the Penn Bioinformatics Core.
Women having children at older ages and the growing availability of fertility treatments has led to a marked increase in the birth of twins: In 2009, one in every 30 babies born in the United States was a twin compared with one in every 53 in 1980. The findings, presented by Michigan State University's Barbara Luke this week at the 14th Congress of the International Society of Twin Studies in Florence, Italy, have important health implications, including greater morbidity and mortality risks and higher health care costs. "Prior to 1980, the incidence of U.S. twin births was stable at about 2 percent of all births, but it has risen dramatically in the past three decades, " said Luke, noting twin births increased for women of all ages, with the largest increases among women aged 30 and older.
An international team led by scientists at A*STAR's Institute of Medical Biology (IMB) discovered that a protein, called TRIM28, normally present in the mother's egg, is essential right after fertilisation, to preserve certain chemical modifications or 'epigenetic marks' on a specific set of genes. This newly published study paves the way for more research to explore the role that epigenetics might play in infertility. Previous studies have shown that both nuclear reprogramming as well as 'imprinting' are vital for the survival and later development of the embryo. However, the underlying mechanisms governing the intricate interplay of these two processes during the early embryonic phase have not been clear, until now. Nuclear Reprogramming Immediately after fertilisation, the majority of the 'epigenetic marks' on the DNA from the sperm and egg cells are erased.
A study in The Journal of Cell Biology describes how a secreted enzyme helps egg cells avoid being fertilized by more than one sperm. Because polyspermy disrupts embryonic development, oocytes take several steps to ensure they only fuse with a single sperm. One key step is to prevent additional sperm from binding to the surface of an already-fertilized egg, a blockade that involves the release of secretory granules and cleavage of a protein called ZP2, a component of the zona pellucida matrix that surrounds eggs. ZP2 is cleaved at a site targeted by the astacin family of metalloendoproteases - enzymes that cut proteins into smaller fragments. Researchers from the NIH's National Institute of Diabetes and Digestive and Kidney Diseases therefore investigated the function of ovastacin, an astacin family member expressed in oocytes.
A new study from the US finds few young women being treated for cancer take steps to preserve their fertility, for instance so they can start a family later. Dr Mitchell Rosen, of the University of California, San Francisco (UCSF), and colleagues, also found disparities among different groups of young women, with some more likely to take steps to freeze eggs or embryos than others. Writing in the 26 March early online view of the journal Cancer, the researchers say their findings show there is a need to boost provisions of counseling on fertility preservation to women of reproductive age undergoing cancer treatment. Rosen told the press: "Although more women are getting counseled regarding reproductive health risks, many women are still not receiving adequate information about their options at the time of cancer diagnosis.