Space flight’s detrimental effects on muscle structure, metabolism and function decrease the work capacity of the muscle. Dr. Marco E. Cabrera is investigating changes in muscle fiber that occur from space flight and exercise, and he is developing a mathematical model to predict the work capacity of muscles during and after space flight. This model will calculate an astronaut’s muscle conditions and identify efficient methods of rehabilitation.
Overview
Metabolic Adaptations of Skeletal Muscle to Training/Detraining. A Systems Model
Principal Investigator:
Marco E. Cabrera, Ph.D.
Organization:
Case Western Reserve University
Technical Summary
Space travel (detraining) has detrimental effects on skeletal muscle structure, metabolism and function, including reductions in muscle size, strength and endurance. Exercise (training) in space can counteract some of these deleterious effects. Indeed, experimental studies are still being conducted to determine both the cause of muscle deterioration and the exercise training programs needed to counteract the detrimental effects of long-duration space travel on muscle function. In addition to obtaining relevant metabolic data from space and ground-based studies, physiologically-based computational models of human function are needed to integrate cellular to whole-body data and to provide a framework for quantitative understanding of the skeletal muscle metabolic responses to exercise in the trained and detrained states.
The specific aims of this project are:
- To identify the metabolic adaptations to training and detraining in order to develop databases containing A). information on the structural, metabolic and functional adaptations of skeletal muscle to microgravity and exercise training, and B). the underlying biochemical mechanisms mediating these adaptations;
- To develop mathematical models of intermediary metabolism in skeletal muscle that account for the effects of training and detraining;
- To investigate the relative significance of model parameters affected by training or detraining on work capacity and efficiency, and;
- To simulate the effects on skeletal muscle intermediary metabolism and energetics of space flight and exercise in space, to quantitatively test the hypotheses that after a period of space travel or exercise training, the observed changes in the rates of carbohydrate and fatty acid oxidation in skeletal muscle are a result of A). a partial conversion of slow-twitch to fast-twitch fibers, and B). alterations in glycolytic and oxidative enzymes.
During the second year of the project, we continued the development and implementation of a computational model of skeletal muscle metabolism that integrates cellular, tissue and whole-body data and that incorporates specific parameters that have been identified as playing a major role in the responses to training and detraining such as muscle mass and enzyme activities. Computer simulations of responses to moderate exercise were performed on three muscle models representing different states: A). normal sedentary subject; B). trained subject, and; C). detrained subject. Then, we contrasted the exercise responses resulting from the model of a trained muscle to those from the model of a detrained muscle.
We also continued collaborating with other NSBRI investigators in the development of:
- A comprehensive model of the human body and its responses to exercise in collaboration with Dr. Martin Kushmerick (Muscle Alterations Team) and Dr. James Coolahan (Cardiovascular Alterations Team), and
- Methods to evaluate the effectiveness of exercise training programs in space in collaboration with Dr. Babs Soller (Smart Medical Systems Team).
This project's funding ended in 2005