Autor:innen:
Christoph Hoffmann | Institute for Clinical Chemistry and Pathobiochemistry, University Hospital Tübingen | Germany
Patrick Schneeweiß | University Hospital Tübingen | Germany
Dr. Lisa Kappler | Institute for Clinical Chemistry and Pathobiochemistry, University Hospital Tübingen | Germany
Dr. med. Elko Randrianarisoa | University Hospital Tübingen | Germany
Dr. Günter Schnauder | University Hospital Tübingen | Germany
PD Dr. Jürgen Machann | Section on Experimental Radiology, Department of Diagnostic and Interventional Radiology, University Hospital Tübingen | Germany
Prof. Dr. Fritz Schick | Section on Experimental Radiology, Department of Diagnostic and Interventional Radiology, University Hospital Tübingen | Germany
Prof. Dr. Andreas Fritsche | Department of Internal Medicine IV, University Hospital Tübingen | Germany
Prof. Dr. med. Martin Heni | Department of Internal Medicine IV, University Hospital Tübingen | Germany
Prof. Dr. Andreas Nieß | University Hospital Tübingen | Germany
Prof. Dr. Hans-Ulrich Häring | Department of Internal Medicine IV, University Hospital Tübingen | Germany
Prof. Dr. Cora Weigert | Institute for Clinical Chemistry and Pathobiochemistry, Department for Diagnostic Laboratory Medicine, University Hospital Tübingen | Germany
Dr. Anja Böhm | Department of Internal Medicine IV, University Hospital Tübingen | Germany
Introduction
Adaptations in skeletal muscle mitochondria are considered to play an important role in the beneficial effect of exercise on metabolic control, while the contribution of adipose tissue is less clear.
Methods
26 obese, sedentary participants (17f/9m, 30±8years) performed an 8-week supervised exercise intervention at 80% VO2peak. Mitochondrial respiration was analyzed in muscle fibers and subcutaneous adipose tissue by high resolution respirometry. Body composition was assessed by whole body MR imaging, hepatic lipids by MR spectroscopy.
Results
Training increased the individual anaerobic threshold (IAT 1.1±0.3 vs. 1.3±0.3W/kg; p < 0.001) and cardiorespiratory fitness (VO2peak 25±4 vs. 27±5ml/min/kg; p=0.005). BMI was slightly reduced (31.5±4.2 vs. 31.2±4.3kg/m2; p=0.03). Specifically, subcutaneous adipose tissue (-3%; p=0.01), femoral adipose tissue (-4%; p=0.02), and liver fat content decreased (-22%; p=0.0086). Ex-vivo respirometry revealed that oxygen flux in muscle fibers was higher than in adipose tissue. Relative to total phosphorylating respiration, muscle mitochondria had higher complex I-linked respiration, while adipose tissue exhibited higher fatty acid and complex II-linked respiration. In muscle fibers, training increased complex I-linked and maximal coupled and uncoupled respiration (all p < 0.01), while in adipose tissue only uncoupled respiration was increased (p=0.007). The effects of training on IAT, VO2peak as well as BMI, subcutaneous and ectopic did not correlate with changes in skeletal muscle and adipose tissue respiration.
Conclusions
The data provide evidence for differences in substrate oxidation and training response of muscle and adipose tissue mitochondria. They suggest that improved in-tissue respiration is an independent contributor to the beneficial effects of exercise.