Owing to the changing lifestyle of women, infertility has become a common cause of concern. Many studies were uncovered in the past but the concrete solution is yet to be found. A new study by investigators from Johns Hopkins now suggests that altering of a gene also meant for regulation of cholesterol in the bloodstream appears to affect the progesterone production in women making it a possible wrongdoer in a substantial number of cases of their infertility.
A simple blood test for this variation of the scavenger receptor class B type 1 gene (SCARB1) was also created by the group though it mentioned that there is no affirmed therapy yet to attend the problem in infertile women.
A common link was found between the studies conducted on female mice and the one conducted on women with a history of fertility. In both the cases the link between deficiency in these receptors for HDL i.e the real healthy cholesterol and infertility appeared to be clear. The Hopkins team seems to be positive in tracing the genetic clue to infertility and developing a treatment for it as well if the study moves ahead as expected. The treatment is known to have been effective in female mice.
“Infertility is fairly common and a lot of the reasons for it are still unknown,” warns endocrinologist Annabelle Rodriguez, M.D., an associate professor of medicine at the Johns Hopkins University School of Medicine and the leader of the study. “Right now, the benefit of this study is in knowing that there might be a genetic reason for why some women have difficulty getting pregnant. In the future, we hope this knowledge can be translated into a cure for this type of infertility.”
As a part of their study Rodriguez and her colleagues collected and examined the ovarian cells and fluid collected from 274 women unable to become pregnant for various reasons and undergoing in vitro fertilization (IVF) between November 2007 and March 2010. Around 207 of them proceeded to have their eggs collected followed by the process of fertilization of the eggs and implantation in their wombs.
2 days after the embryo transfer the scientists had to see for any signs of gestation sac or fetal heartbeat that could be affirmed only by evidence. All the nine women in the group with mutated SCARB1 were devoid of this evidence .This implied that none of them were pregnant. According to Rodriguez the genetic variation could be present in 8 to 13 percent of the population.
Despite being supplemented with progesterone as part of the IVF process, the levels of the same were found to be less in the nine women with the altered gene. Progesterone is crucial for sustaining a pregnancy in the earliest stages.
According to Rodriguez, who is also director of the Johns Hopkins Diabetes and Cholesterol Metabolism Center, her work was based on the studies with mice genetically programmed without the receptor for good cholesterol. In the absence of the receptor, their bodies were unable to take in the excess cholesterol and therefore contained unexpectedly huge amounts of HDL in the blood Risk of heart failure and infertility in the female mice ensue thereon.
A certain cholesterol medication called Probocal developed years ago was known to lower levels of cholesterol circulating in the blood and also restored the rodents’ pregnancy. This particular treatment was found by the scientists of The Massachusetts Institute of Technology. This drug is available in Japan in certain conditions although it has not been accepted in the United States, the main reason being substantial reduction of HDL which is actually a positive side effect for the mice without HDL receptors.
In the days to come, Rodriguez hopes to detect if Probucol can help infertile women with the gene variation get pregnant by conducting a clinical research. She also plans to track the genetic factor associated with pregnancy by collecting data on HDL levels in infertile women with the genetic variation
The study is published online in the journal Human Reproduction.