3 Clinical Trials for Various Conditions
Sarcopenia is a major health problem among the rapidly expanding elderly population in our society. Disabilities directly related to muscle weakness, and indirectly related to changes in body composition and metabolic dysfunctions, are causing a staggering toll in disability and health care costs. Osteopenia occurs almost simultaneously with sarcopenia in the elderly population and muscle weakness increases the risk for falls and therefore, fractures. Although these issues have been separate addressed in several studies, an integrated investigational approach to better understand the pathogenesis of sarcopenia and other age-related metabolic abnormalities and to investigate the potential role of androgens have not been undertaken in a comprehensive manner. The program contains four independent research programs, each representing different research disciplines, and four separate cores supporting the four projects. The main focus of the project is to determine the effect of the replacement of testosterone in elderly men and DHEA in elderly men and women and to compare these effects with placebo treatment over a two-year period. Project 1, "Effect of Androgen Replacement on Muscle Metabolism" will specifically determine whether these interventions have a differential effect on size and quality of muscle in terms of strength and metabolic functions. Project 2, "Effect of Androgen Replacement on Bone Metabolism," will determine the effects of this intervention on bone mineral density and markers of bone turnover. Project 3, "The Effect of Androgen Replacement on Carbohydrate Metabolism," will determine whether the age-associated decrease in circulating androgens contributes to the alterations in carbohydrate metabolism that are commonly observed in the elderly and on insulin action, insulin secretion, and glucose effectiveness. Project 4, "Effect of Androgen Replacement on Fat Metabolism" will determine whether changes in fat distribution that occur with aging could result from differences in regional fatty acid uptake and systemic fatty acid kinetics, and whether these determinants of fat distribution are altered by the interventions. The data emerging from these studies will be integrated to determine the intervention of sarcopenia with other metabolic changes and hopefully will contribute to a better understanding of muscle, bone, carbohydrate and fat metabolism. This study will hopefully form the scientific basis for future trials of androgen replacement in the elderly.
Bone strength -the main determinant of bone fracture- is a function not only of bone mineral density (BMD) and microstructure, but also of its microenvironment, including bone marrow fat (BMF). The adrenal steroid dehydroepiandrosterone (DHEA) -the main precursor for estrogens and androgens in postmenopausal women- as well as bone-loading exercise, increase BMD in older women, however, their effects on BMF are largely unknown. This study has high potential to unveil the hormonal and mechanical effects of DHEA and exercise on BMF, respectively, and to elucidate longitudinal associations of BMF with bone strength in older women with bone loss.
To determine whether the musculoskeletal adaptations to bone-loading exercise can be significantly augmented in older women (aged 60-85) with low bone mass (osteopenia; T-scores \<-1.0 and \>-2.5) or moderate osteoporosis (T-scores \< -2.5 and \>= -3.0) and by restoring serum DHEAS to young adult levels by oral DHEA replacement.