Scientist's message: ‘A woman is not a small man’
By Clint Talbott
In the United States, more women die of cardiovascular disease than succumb to the next seven causes of death combined. And while the rate of cardiovascular disease has been steadily declining in men, it has remained relatively constant among women.
Yet most drugs and devices used to treat heart disease were developed with male subjects and then applied to women—assuming that scaling down is a sufficient strategy for gender adaptation.
Leslie Leinwand, professor of molecular, cellular and developmental biology at the University of Colorado, has a memorable response to that assumption: A woman is not a small man.
Leinwand, who is also chief scientific officer of the Colorado Initiative in Molecular Biotechnology, gave a presentation on that subject in November as she was recognized as a professor of distinction in the College of Arts and Sciences.
Leinwand used the occasion to emphasize one of her research interests, tailoring medicine to each gender. As she noted, women suffering from heart attacks might have different and sometimes milder symptoms than men.
Those symptoms might include sudden onset of weakness, shortness of breath, fatigue, body aches and the like. Sometimes, these symptoms are misdiagnosed as anxiety, Leinwand noted.
Low doses of aspirin are beneficial for both genders, though in different ways, she added. In women, low-dose aspirin helps prevent stroke but not heart attacks. In men, low-dose aspirin helps prevent heart attacks but not stroke.
Such facts emphasize the inadequacy of studying drugs and devices in men only, she said. That trend was driven by economics, because it’s cheaper to study only one sex than to study two. At the same time, Leinwand said, researchers are now beginning to conduct studies that include female animals and women.
That is a welcome change, she suggested, given that gender differences extend to other areas, including responses to exercise and to the effect of cancer on the heart.
Mice, for instance, may run 25 to 31 miles each week. If humans ran comparable distances, they’d be logging nearly 350 miles per week, an astonishing number even in Boulder, Leinwand noted.
But female mice may run twice the distance of males each week, and they have stronger cardiac responses to a given amount of exercise than males.
“This is something that would be extremely interesting to understand,” Leinwand observed.
Similarly, there are gender differences in cancer’s effects on the heart. These differences have been studied in mice and observed in humans. Males afflicted with cancer lose more body weight and cardiac mass than do females.
That difference appears to stem from higher levels of estrogen in females, Leinwand said. When researchers block estrogen in female mice, they experience weight loss and heart-mass loss much like males do.
At the same time, if male mice are given estrogen, they get worse, not better, Leinwand added.
This could be relevant to humans who ingest large quantities of soy, particularly in the form of concentrated supplements or infant formula. Americans, she noted, spent $8 billion on soy products in 2008.
Soy contains plant estrogens, called phytoestrogens, which are found in high concentrations in soy supplements and infant formula, but in lower levels in tofu, tempeh and miso.
Normal laboratory mouse food is soy-based, and male mice fed this way have worse heart health than do female mice, Leinwand noted.
A question is whether humans can ingest similar levels of phytoestrogens by eating a soy-rich diet. Infants fed soy-based formula may be at risk, Leinwand said, adding that it’s unclear whether taking concentrated soy phytoestrogens in adulthood would pose a similar risk.
At the same time, she suggested, it may be unnecessary to take soy supplements to augment cardiovascular health, particularly because there are no data supporting the claim that these supplements help lower cholesterol levels in people.
The honorific title College Professor of Distinction is reserved for scholars and artists of national and international distinction who are also recognized by their college peers as teachers and colleagues of exceptional talent. Leinwand and Fred Anderson, a professor of history and director of the CU Honors Program, are this year’s honorees.
Leinwand holds a doctorate from Yale University and has been a professor at CU-Boulder since 1995. She has been elected as a Fellow of the American Association for the Advancement of Science and been named a Marsico Endowed Chair of Excellence for her teaching and research activities associated with her studies of genetic heart defects. She was also named a Howard Hughes Medical Institute Professor in 2006, which promotes the involvement of very research active faculty in undergraduate science education.
Leslie Leinwand, professor of molecular, cellular and developmental biology at the University of Colorado, has been named a professor of distinction in the College of Arts and Sciences.
In the United States, more women die of cardiovascular disease than succumb to the next seven causes of death combined. And while the rate of cardiovascular disease has been steadily declining in men, it has remained relatively constant among women.
Yet most drugs and devices used to treat heart disease were developed with male subjects and then applied to women—assuming that scaling down is a sufficient strategy for gender adaptation.
Leslie Leinwand, professor of molecular, cellular and developmental biology at the University of Colorado, has a memorable response to that assumption: A woman is not a small man.
Leinwand, who is also chief scientific officer of the Colorado Initiative in Molecular Biotechnology, gave a presentation on that subject in November as she was recognized as a professor of distinction in the College of Arts and Sciences.
Leinwand used the occasion to emphasize one of her research interests, tailoring medicine to each gender. As she noted, women suffering from heart attacks might have different and sometimes milder symptoms than men.
Those symptoms might include sudden onset of weakness, shortness of breath, fatigue, body aches and the like. Sometimes, these symptoms are misdiagnosed as anxiety, Leinwand noted.
Low doses of aspirin are beneficial for both genders, though in different ways, she added. In women, low-dose aspirin helps prevent stroke but not heart attacks. In men, low-dose aspirin helps prevent heart attacks but not stroke.
Such facts emphasize the inadequacy of studying drugs and devices in men only, she said. That trend was driven by economics, because it’s cheaper to study only one sex than to study two. At the same time, Leinwand said, researchers are now beginning to conduct studies that include female animals and women.
That is a welcome change, she suggested, given that gender differences extend to other areas, including responses to exercise and to the effect of cancer on the heart.
Mice, for instance, may run 25 to 31 miles each week. If humans ran comparable distances, they’d be logging nearly 350 miles per week, an astonishing number even in Boulder, Leinwand noted.
But female mice may run twice the distance of males each week, and they have stronger cardiac responses to a given amount of exercise than males.
“This is something that would be extremely interesting to understand,” Leinwand observed.
Similarly, there are gender differences in cancer’s effects on the heart. These differences have been studied in mice and observed in humans. Males afflicted with cancer lose more body weight and cardiac mass than do females.
That difference appears to stem from higher levels of estrogen in females, Leinwand said. When researchers block estrogen in female mice, they experience weight loss and heart-mass loss much like males do.
At the same time, if male mice are given estrogen, they get worse, not better, Leinwand added.
This could be relevant to humans who ingest large quantities of soy, particularly in the form of concentrated supplements or infant formula. Americans, she noted, spent $8 billion on soy products in 2008.
Soy contains plant estrogens, called phytoestrogens, which are found in high concentrations in soy supplements and infant formula, but in lower levels in tofu, tempeh and miso.
Normal laboratory mouse food is soy-based, and male mice fed this way have worse heart health than do female mice, Leinwand noted.
A question is whether humans can ingest similar levels of phytoestrogens by eating a soy-rich diet. Infants fed soy-based formula may be at risk, Leinwand said, adding that it’s unclear whether taking concentrated soy phytoestrogens in adulthood would pose a similar risk.
At the same time, she suggested, it may be unnecessary to take soy supplements to augment cardiovascular health, particularly because there are no data supporting the claim that these supplements help lower cholesterol levels in people.
The honorific title College Professor of Distinction is reserved for scholars and artists of national and international distinction who are also recognized by their college peers as teachers and colleagues of exceptional talent. Leinwand and Fred Anderson, a professor of history and director of the CU Honors Program, are this year’s honorees.
Leinwand holds a doctorate from Yale University and has been a professor at CU-Boulder since 1995. She has been elected as a Fellow of the American Association for the Advancement of Science and been named a Marsico Endowed Chair of Excellence for her teaching and research activities associated with her studies of genetic heart defects. She was also named a Howard Hughes Medical Institute Professor in 2006, which promotes the involvement of very research active faculty in undergraduate science education.