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Gender differences affect inflammation, CV repair
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Disparities between the sexes can affect inflammation, aging and hormonal changes, and, therefore, researchers are seeking a better understanding of cardiovascular disease to limit its progression and mortality among women, according to Doris A. Taylor, PhD, FAHA, FACC.
However, the underlying mechanisms for these differences remain unclear, she said.
“We are beginning to think that by looking at our body’s ability to repair itself, these endogenous processes, and how these stem cells and progenitor cells in our body normally participate in that process, are very much related to being male or female; the time frame during which we have the capacity to mediate that repair differs is related to hormones,” Taylor, of the Texas Heart Institute at St. Luke’s Episcopal Hospital in Houston, told Endocrine Today. “Clinically, we need to start thinking about this whole endogenous repair process and how it underlies everything that happens with the patient.”
Doris A. Taylor
Quantifying endogenous repair
During her presentation at the Wulf H. Utian Endowed Lecture at the NAMS 2013 Annual Meeting, Taylor spoke about aging as a failure of stem cells; that as patients age, not only do they lose cell numbers, but cell function as well.
“Men tend to lose many of these cells much earlier than women. Just like women catch up with men in about the seventh decade of life in terms of CVD, cell loss seems to occur and catch up about the same period,” Taylor said.
Perhaps, Taylor said, this failure of endogenous repair is one of the reasons why men develop CVD earlier than women.
As men and women age, there is a decrease in the frequency of blood circulating stem cells that express the stem cell marker CD34, which varies between men and women. These cells have an important role in supporting blood vessel growth after myocardial ischemic episodes caused by coronary artery disease, according to data provided by Taylor.
Age-, hormone-related responses
Inflammation is the cue that nature uses to tell the body there is an injury, Taylor said. Without proper mobilization of cells, inflammation may continue. Early inflammation is a good thing; chronic inflammation signals improper repair, she added.
“Women may have a different inflammatory response compared with men because women have to be able to carry a pregnancy to term,” Taylor said. “The heart in young women is much stiffer than the heart in men. When patients become pregnant, they must be able to pump four times their normal blood volume, and recover from that within a 24-hour period after delivery.”
She said some women who do not recover are likely to develop pregnancy-associated heart failure. Similarly, menopause is a major risk factor for CVD.
Complex research on the horizon
With enough stem and progenitor cells, scaffolding that supports organ function and vasculature to feed the cells, organs and tissues, it is possible to build an organ needed to mediate repair with cadaveric hearts, according to Taylor.
“What we have learned is that even the underlying structure of organs and tissues differ between men and women,” she said.
Taylor is currently conducting studies with colleagues that may demonstrate how hormone levels appear to be directly related to the number of stem or progenitor cells that individual patients have, and how hormone loss and hormone-type loss differ between men and women. – by Samantha Costa
For more information:
Taylor DA. NAMS/Pfizer Wulf H. Utian Endowed Lecture: Sex differences in cardiovascular repair. Presented at: the North American Menopause Society 24th Annual Meeting; Oct. 9-12, 2013; Dallas.
Disclosure: Taylor reports financial ties with Miromatrix Medical Inc.