Published by Communications and Public Affairs (519) 824-4120, Ext. 56982 or 53338
November 20, 2002
Biomedical scientist explores role of immune system in pregnancy
University of Guelph researcher Marianne van den Heuvel has been named the first recipient of an Ontario Women’s Health Scholars Post-Doctoral Fellow Award for her research on the role of the immune system in establishing a healthy pregnancy.
The research may offer new insights into the probability of success in achieving pregnancy through in vitro fertilization. “In order for a pregnancy to be successful, the immune system must recognize the pregnancy so that it can contribute,” said van den Heuvel, a biomedical scientist in the Ontario Veterinary College.
The Ontario Women’s Health Scholars Post-Doctoral Fellow Award, worth $41,000, is supported by the Ontario Women’s Health Council and funded by the Ontario Ministry of Health and Long-Term Care. Open to master’s and doctoral candidates and post-doctoral researchers, the awards are designed to ensure that Ontario attracts and retains pre-eminent scholars specializing in women’s health.
van den Heuvel’s interest in the reproductive system began years ago when she returned home to work on her family’s dairy farm after a 10-year career in land resource science. “We would have high-production cows producing milk like crazy, but we couldn’t get them to calf again,” she said. “Our vet said he had seen this at other farms, too. I wondered if it was because their immune systems were affected by high stress levels.”
In her research, van den Heuvel is focussing on natural killer or “NK” cells, which exist in white blood cells and whose activity may be an indicator of a woman’s ability to achieve a viable pregnancy. Natural killer cells are aptly named because their role is to recognize and kill foreign cells such as viral or tumour cells, as part of the body’s natural immune response. Past research has shown that during pregnancy, NK cells migrate to the uterus, but they don’t typically recognize a fetus as foreign and launch an attack, something van den Heuvel finds fascinating. “That was always a puzzle from an immunology standpoint because the fetus is actually foreign,” she said. “It’s part of the mother and also part of the father. It should be rejected by the body.”
Of particular interest to her is the ability of NK cells to act as indicators of a healthy immune system. Using blood samples from healthy fertile women of child-bearing age who are not taking any hormone supplements such as birth control pills, van den Heuvel has mapped the adhesion of NK cells to the uterus against the stages of the menstrual cycle. She’s found that in fertile women, NK cell activity follows a monthly cycle. There is an influx of NK cells into the uterus on ovulation. If pregnancy doesn’t occur, the cells are shed along with the unfertilized egg.
van den Heuvel’s research group has partnered with the reproductive endocrinology and infertility programs at the University of Western Ontario, a facility that helps women trying to bear children through in vitro fertilization. She plans to compare the levels of NK adhesion in these women, who are taking hormone supplements, with the NK adhesion mapping she has created. She expects that abnormal NK activity may explain why some of the women have not been able to achieve viable pregnancies.
“About 10 per cent of couples are infertile, and it’s hard to figure out why,” she said. “This work may be a way of identifying problems affecting a woman’s ability to have children. The problem could be with the woman’s immune system rather than the reproductive system.”
Because in vitro fertilization is such an expensive and intense procedure (costing about $10,000 per cycle), van den Heuvel hopes to be able to establish a test to predict the chances of success through in vitro fertilization. “For women who have something wrong with their immune system, maybe there are other treatment options available.”
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