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APS Contact: Donna Krupa

Email: dkrupa@the-aps.org

Phone: 301.634.7209

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Why Do Men And Women Respond Differently To The Same Disease?

Bethesda, Md. – More than 100 research scientists will examine hormones, gender and how they can interact to cause heart and kidney disease. The conference, entitled Sex and Gender in Cardiovascular-Renal Physiology and Pathophysiology, is being held August 9-12, 2007 in Austin, TX, and is hosted by the American Physiological Society (APS; www.The-APS.org).  Conference highlights include presentations on: 

TESTOSTERONE REPLACMENT THERAPY: How Safe for Aging Men? – For decades, older women have taken hormone replacements to replenish estrogen and progesterone levels lost to aging. More recently, testosterone (the most important male hormone) supplements have been used by aging men to improve their muscle mass, bone strength, libido and quality of life. In 2002, the number of elderly American men taking testosterone replacement therapy was nearly 819,000, and the number is growing. The increased use has occurred despite the fact that the cardiovascular effects of chronic testosterone treatment in aging males are largely unknown, and the safety of testosterone replacement has not been evaluated.  A team of researchers has been using an animal model to investigate potential links between testosterone supplements and cardiovascular and renal disease.

ACUTE SLEEP DEPRIVATION LEADS TO CHANGES IN NIGHTTIME URINE PRODUCTION FOR MEN AND WOMEN; Lack of sleep causes men to produce more urine than women, making “bathroom breaks” likely – Our body’s production of urine follows a circadian rhythm. During the day, we experience greater urinary frequency; at night, urine production declines, enabling us to get uninterrupted sleep. The regulation of urine excretion during nighttime hours is influenced by many factors, including hormones, blood flow (hemodynamics), and sleep-related factors. The mechanism behind the day/night changes is not yet clear. Danish researchers have examined the urinary patterns of sleep-deprived volunteers and have found that a lack of sleep leads to increased urinary output and more salt in urine. The findings were found to be more prevalent in males than females.

THE “FEMALE ADVANTAGE” IN KIDNEY DISEASE DOES NOT EXTEND TO DIABETIC WOMEN; Studies suggest kidney disease in diabetic women may be result of imbalances in hormonal ratios, not an absolute level of estrogen – Women have a “female advantage” when it comes to chronic kidney disease. When compared to men, they have fewer and less severe episodes of this disorder throughout most of their lives. That advantage disappears, however, when the woman is diabetic. For reasons still unclear, diabetic women – regardless of age – are diagnosed with kidney and heart diseases almost as frequently as men.  What is it about diabetes that predisposes a woman to develop renal disease at levels generally associated with her male counterpart?

IDENTIFYING MARKERS IN MENOPAUSAL WOMEN AT RISK FOR DEADLY BLOOD CLOT – In women, hormone therapy is a risk factor for venous thrombosis, a blood clot forming deep inside the vein. Despite the fact that the disorder is rare, it increases exponentially during menopause and can be deadly. The hormone trials conducted thus far, focusing on proteins in blood coagulation, have not yet led to a risk profile, thereby precluding identification of women at risk. Now, a team of Mayo Clinic researchers has developed a novel concept that uses blood platelets to define thrombotic risk. The team is testing its theory as part of the Kronos Early Estrogen Prevention Study (KEEPS).

SUGAR AND SPICE AND EVERYTHING NICE: HEALTH DIFFERENCES IN NEWBORN GIRLS AND BOYS; Two new studies examine why death rates for female infants are higher after heart surgery and why female donor livers may be less effective for transplants For generations, girls have whimsically been said to be made of “sugar and spice and everything nice,” and boys from “snakes and snails and puppy dog tails.” Inherent in these loving references is the fact that females and males are different, both when they are healthy and when they are ill.  Two new studies using an animal model may lead to a better understanding of sex-based health discrepancies found among some newborns. One study has found that gender differences in the heart may help explain why infant girls are more likely to die following heart surgery. The other study has determined that the rapid accumulation of acid in newborn female livers may shed light on why pediatric liver transplants are less successful when the livers are donated from infant girls.

BENEFITS OF CARDIO EXERCISE ARE GREATER FOR THE FEMALE HEART – While cardiovascular disease occurs in both men and women, it does not affect them in the same way. Risk factors and protective factors for heart diseases are likewise unequal. The molecular mechanisms responsible for these differences are so far unknown, but some believe it is due to chromosomal linked genes or sexual hormones such as estrogen and testosterone. While the mechanisms behind the differences are unknown, the physiological differences are clear. A new study examining chronic exercise in male and female mice finds that moderate long-term exercise provokes a sex-dependent cardiac adaptation that is different for females versus males. The findings may eventually help improve treatment strategies for women and men with heart disease.

STUDY SUGGESTS ESTROGEN DEFICIENCY CAN LEAD TO OBESITY-INDUCED HIGH BLOOD PRESSURE FOR POSTMENOPAUSAL WOMEN –
At menopause, women lose hormone protection against heart (cardiovascular) and kidney (renal) diseases, and are likely to become obese. A research team has tested the idea that estrogen deficiency in aged females may trigger the development of high blood pressure and obesity. The results of their study, using an animal model, suggest that estrogen depletion can have these effects.

FEMALE GENDER PROVIDES AN ADVANTAGE IN RENAL DISEASES; Women with certain renal diseases progress at slower rate than men – Gender influences the prevalence and progression rate of many renal diseases. The physiology behind gender differences and renal disease is still uncertain, but sex hormones (estrogen, testosterone) are thought to contribute to the differences. Estrogen especially may exert certain cellular effects on the kidney because it can suppress the growth of scar tissue as well as affect various growth factors which impact the kidney. Researchers examining the  cells located around the small blood vessels of the kidneys have found that the female hormone estradiol inhibited the activity of transforming growth factor (TGF-β); TGF-β promotes scarring of the kidney in many renal diseases; estradiol does this by preventing TGF-β from activating the enzyme (casein kinase 2) which affects collagen production. In this way, estrogen reduces the production of collagen in these cultured cells and may reduce scarring in renal disease.

GRAPES, SOY AND KUDZU BLUNT SOME MENOPAUSAL SIDE EFFECTS; Memory loss, hypertension and insulin resistance reduced in several animal studies – A decade ago, treatment for menopausal women at relatively high risk for memory loss, high blood pressure and diabetes was often long-term hormone replacement therapy (HRT). Since then, studies have shown that extensive use of HRT is associated with significant adverse effects and so alternatives have been sought. Among the alternatives are dietary polyphenols which are found in grapes, soy and kudzu. Researchers have found that these edibles can blunt cognitive loss, hypertension and insulin resistance in experimental models.

Physiology is the study of how molecules, cells, tissues and organs function in health and disease. Established in 1887, the American Physiological Society (APS) was the first U.S. society in the biomedical sciences field. The Society represents more than 10,500 members and publishes 15 peer-reviewed journals with a worldwide readership.