Impact of low testosterone on frailty and cardiac structure and function in aging male and female mice

Heart disease is a leading cause of death worldwide and is a great challenge for our aging population. Testosterone levels decline with age in both men and women, while the risk of heart disease increases. In fact, low testosterone levels have been linked to diseases such as heart failure, but the relationship between the two is unclear. Some studies have investigated the effects of testosterone on the heart but whether testosterone has good or bad effects on the heart, especially in older and more vulnerable individuals, is not known. Our study will investigate the effects of low testosterone on heart health, and we will look at how it affects the structure and function of the heart as well as in individual cells from male and female hearts. We will also investigate the role of testosterone on the overall health in older mice. We will evaluate this by measuring their frailty using a clinical frailty index developed in the Howlett lab. We also want to find out whether testosterone supplementation is helpful or harmful. What is unique about our study is that we will use aging mice (equivalent to 60-70-year-old humans) for our experiments. This is important because the prime candidates for testosterone supplementation, and those most at risk for heart disease, are frail older people. This project will help us understand the links between testosterone, aging, and heart disease, and help us identify why older men and women develop diseases like heart failure.