MedicalResearch.com Interview with:
A.Univ.-Prof. Dr. Judith Lechner
Div. Physiology
Medical University of Innsbruck
Innsbruck Austria
MedicalResearch.com: What is the background for this study? What are the main findings?
Dr. Lechner: Women are not just small men. Sex differences affect most, if not all the organ systems in the body. Over the past decades biomedical researchers have been mainly using male models. Therefore, there is a significant gap in knowledge of female physiology except for organ functions involved in reproduction. While the necessity to fill in these gaps has been advocated, our understanding of sex and gender differences in human physiology and pathophysiology is still limited. This holds especially true for the kidneys, e.g. while international registries show that fewer women than men are in need of renal replacement therapy due to end stage renal disease, the potentially underlying causes are still not known.
The aim of our study was to find out, if hormone changes due to the female menstrual cycle would affect normal renal cells. For this purpose, urinary samples of healthy women of reproductive age were collected daily and analyzed for menstrual cycle-associated changes of marker proteins. Specifically, two enzymes (Fructose-1,6-bisphosphatase, Glutathione-S-transferase alpha) were measured, which are intracellular components of proximal tubular cells, a key population of renal cells. Upon cell damage, these enzymes are released into the urine, qualifying them as clinical markers for early detection of tubular injury. Since even in healthy persons low amounts of these enzymes can be detected in the urine, we used these marker proteins to analyze potential effects of the female hormone cycle on normal functioning of this cell population. As a result, we could detect transient increases of Fructose-1,6-bisphosphatase and Glutathione-S-transferase alpha correlating with specific phases of the female hormone cycle, namely ovulation and menses.
This finding suggests that cyclical changes of female hormones might affect renal cell homeostasis, potentially providing women with an increased resistance against kidney damages. Thus, recurring changes of sex hormone levels, as during the natural menstrual cycle, might be involved in periodic tissue re-modeling not only in reproductive organs, but to a certain extent in the kidneys as well.
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