Washington, June 17 : A new study from University of Missouri has revealed that postmenopausal women are likely to face complex changes in the brain's vascular system, something that make explain why the risk of heart disease and stroke increases after menopause.
Before menopause, the vascular system depends on estrogen for maintenance. When the body decreases its estrogen production, the body is unable to regulate blood vessels like it did before. After a period of deterioration, the body learns to adapt to the estrogen loss and eventually maintains the system in a different way.
Scientists believe that currently used estrogen-based hormone therapies may complicate this process and may do more harm than good in postmenopausal women.
"Before menopause, women are much more protected from certain conditions such as heart disease and stroke, but these vascular changes might explain why women lose this protection after menopause," said Olga Glinskii, research assistant professor of medical pharmacology and physiology in MU's School of Medicine and lead author of the study.
"Because the body eventually will naturally adapt to the loss of estrogen, we advise extreme caution when using estrogen-based therapy in postmenopausal women," Glinskii added.
During the study, the scientists removed the ovaries of pigs, which have a reproductive cycle similar to humans, to create postmenopausal conditions.
Two months after the ovaries were removed, they observed dramatic differences in the brain's vascular system. There was a huge loss of micro vessels, and blood vessels became "leaky."
"Eventually, however, the body starts to recognize that it needs blood vessels and starts to adapt through natural responses," said Vladislav Glinskii, assistant professor of pathology and anatomical sciences in MU's School of Medicine and co-senior author of the study.
"If we start adding estrogen to a system that is learning to adapt without it, we upset this transition process. What happens to the vascular system during menopause is complex on many different levels, and we do not know enough to determine the best way to use hormone therapy," Vladislav added.
Virginia Huxley, director of the National Center for Gender Physiology, professor of medical pharmacology and physiology in MU's School of Medicine, and co-senior author of the study said that after menopause, women are more likely to develop vascular diseases.
"The blood vessels are the highways that transport oxygen and other nutrients in our body. After menopause, women are more likely to develop vascular diseases in the 'side streets' or the tiny vessels. In these vessels, the symptoms are more subtle and harder to identify," she said.
The study is recently published in Cell Cycle.