The working group is concerned with the analysis of mitochondrial respiration in homogenised or permeabilised tissue samples or in cell cultures from immortalised or primary cell lines. The analysis is centred on respirometry (high-resolution respirometry), which allows precise recording of O2 consumption under defined conditions. This allows mitochondrial respiration to be recorded at various constant temperatures (4°C - 40°C), pH values and O2 concentrations (>0.001 µM). The analyses are carried out regularly in samples from muscle tissue (heart muscle and skeletal muscle), liver, kidney and neuronal tissue. Various cell types such as cell lines from solid tumours, haematological cell lines, freshly isolated haematological cells (PBMCs, granulocytes), cardiomyocytes, hepatocytes, cell lines of renal origin and primary neurons are also regularly examined. In addition to respirometry, fluorescence spectroscopy has been established in recent years, which allows the mitochondrial membrane potential, ATP production and ROS generation to be measured in parallel with the analysis of mitochondrial respiration.

This working group focuses on immortalised and primary cell cultures. Using a variety of methods (immunofluorescence, Western blot, analysis of mitochondrial function, ROS generation, and FACS analysis), we investigate the pathophysiological mechanisms of sepsis and potential therapeutic measures that could be used in the future for severe sepsis in everyday clinical practice. The _H2Ssystem in particular plays a decisive role here, but also the targeted downregulation of energy metabolism in the sense of "suspended animation".

Another focus of our laboratory is the investigation of the energy metabolism of peripheral immune cells (PBMCs, granulocytes), which are isolated from the blood. The initial aim is to characterise changes in energy metabolism, particularly during sepsis or severe haemorrhage, and possibly to use them as prognostic biomarkers.

Various spectroscopic / spectrometric measurement techniques are used:

Gas chromatography/mass spectrometry (GC/MS) to determine the enrichment rate of test substances that have been labelled with stable isotopes. This allows glucose production and utilisation to be characterised non-invasively, for example, or the activity of individual steps of the Krebs or citric acid cycle to be determined in a cell culture approach. The GC/MS technique also allows sensitive determination of the concentrations of certain markers in plasma, such as sulphide or creatinine.

NDIR spectroscopy: This non-invasive technique can be used to determine the respiratory release of 13CO2 in breath gas in vivo. In the case of orally administered 13C-labelled test substances, the absorption of the test substance in the gastrointestinal tract can be estimated. This approach is used to investigate the functionality of the gastrointestinal tract in critically ill patients in cooperation with the Operative Intensive Care Section of the Anaesthesiology Clinic.

Electron spin resonance (ESR) spectroscopy: Radicals and oxidative stress play an important role in many diseases and biological processes. For a more precise understanding, a precise measurement is required, which we are establishing with the help of the ESR gold standard, which detects radicals in a highly specific manner. We are particularly interested in oxidative and nitrosative stress in biological samples.