Among elderly men, an age-related increase in estrogen may be the culprit behind inguinal hernias. The findings of the study are published in Proceedings of the National Academy of Sciences. The study, led by Dr. Serdar Bulun, chair and the John J. Sciarra Professor of Obstetrics and Gynecology at Northwestern University Feinberg School of Medicine, found the lower abdominal muscles of mouse models are particularly sensitive to estrogen, developing scar tissue in response to increases in estrogen levels that weakens the abdominal wall and eventually causes a hernia.
‘Reduced estrogen with a drug compound prevented the hernias, suggesting new therapy with preventive potential in humans. ’
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"It may make sense to treat at-risk men with an aromatase inhibitor that could decrease estrogen and strengthen the muscle," said Bulun, also a member of the Robert H. Lurie Comprehensive Cancer Center of Northwestern University. Inguinal hernias occur when tissue, such as the intestines, protrudes through the inguinal canal, a weak spot near the groin in the human abdominal wall. These hernias are the most common reason men undergo surgery. There are more than 700,000 inguinal hernia repair surgeries performed each year in the United States, according to the Food and Drug Administration. While the chances of an inguinal hernia increase as men age, the root cause remains unknown.
One other consequence of aging in men is that a larger share of testosterone is converted to estrogen by a hormone called aromatase.
Bulun, whose chief scientific interests include breast cancer and gynecology, was investigating the effects of high estrogen in female mice. One experiment involved boosting estrogen levels by incorporating the human aromatase gene into the mouse genome, creating mice who would convert testosterone into estrogen throughout the body. Originally, he wasn't even interested in the male mice -- until an animal keeper at Northwestern spotted large hernias developing in only the males.
Bulun investigated these mice, finding large swaths of fibroblasts -- scar tissue -- developing in a small muscular sphincter, a structure analogous to the inguinal canal in humans. "We realized the lower abdominal muscle is extraordinarily sensitive to estrogen," Bulun said. "Estrogen causes these fibroblasts to divide rapidly, at a much higher pace than the muscle cells."
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Those patients with greater risk of hernia often have common factors like age or genetics, but overall, Bulun said the best predictor of a future inguinal hernia is a previous one. "If you have to repair a hernia for the second time, the chances of success go down," Bulun said. "If there is a recurrent case, you might be able to supplement the surgical treatment of that patient with medication."
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Source-Eurekalert