IT MIGHT be possible to develop drugs that boost the success rate of IVF by helping embryos to implant in the womb, thanks to the discovery of a molecular pathway involved in the implantation process.
A team led by Jerold Chun of the Scripps Research Institute near San Diego, California, genetically engineered mice so they lacked a receptor for a small signalling molecule called lysophosphatidic acid (LPA). Implantation was less successful in the uterine walls of these mice compared with normal uteri, leading to litters only half as large as normal, the team found (Nature, vol 435, p 105). But the genetically modified embryos were no worse than unmodified ones at implanting in the uteri of normal mice, proving it is the presence of LPA receptors in the uterus, not in the embryo, that matters.
Drugs that boost LPA signalling might have the opposite effect, enhancing implantation, the researchers suggest. However, it is not clear whether the IVF process somehow reduces implantation rates or whether the lower rates are simply a result of abnormalities in the embryos. If the latter is true, enhancing implantation rates might risk increasing the number of birth defects.
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