Third party funded individual grant
Start date : 01.01.2015
End date : 31.12.2016
Among acute acquired myopathies, muscle failure during sepsis is very common and imposes vast threats, also to health care budgets. Mechanisms leading to muscle failure in sepsis are poorly defined. Trigger factors are likely to be related to inflammatory cytokines, either in isolated, but more likely, in concerted action. Characterization of muscle function requires a multidisciplinary approach with strategies from medical biotechnology, bioengineering and kinesiology. Here, we will develop screening technologies to assess muscle functionality at various scales in response to 'in vitro' exposure to single or combinations of inflammatory cytokines (interleukins, interferons, tumor necrosis factor, etc.). Our major hypothesis is that combinations of cytokines (i) specifically alter active force production and (ii) produce a similar proteolysis response as seen in patients. Specific study aims (SA) are:
SA 1: Biomechanics of skeletal muscle fibre bundles incubated with cytokines. Fibre bundles dissected from fast- and slow-twitch muscles are investigated with a novel, automated 'MyoRobot' force transducer, performed under control conditions and following incubations with IL-1, IL-2, TNF-gamma, interferon-ß/g or LPS.
SA2: Biochemical proteolysis and muscle protein synthesis pathway examination in muscle incubated with inflammatory cytokines. Muscles will be incubated with inflammatory cytokines in a tensegrity preserving organ bioreactor. After cytokine incubation, protein and transcriptome analyses of muscle synthesis (Akt, mTor, TGF-ß) and catabolism (NF-kB, ubiquitin proteasome, calpains, etc.) are performed.
SA3: Morphometric advanced multiphoton microscopy of ultrastructural remodeling and sarcomere reorganization due to increased proteolysis. Muscle frozen tissue sections, live small fibre bundles and single fibres are subjected to Second Harmonic Generation Microscopy and quantitative cytoarchitecture morphometry.
Our collaborative project combines complementary expertise to understand a major challenge of modern ICU medicine and provides new Myo-Technologies.