Mark Wefers Bettink

Measuring mitochondrial oxygenation and respiration in vivo in a human endotoxemia model 6 115 Fig 4. Michaelis Menten kinetics of mitochondrial oxygen concentration (mitoPO 2 ). Dynamic measurement of mitochondrial respiration, sampling rate of 1 Hz. Baseline measurement for 10 seconds where P 0 is determined. After a baseline measurement, local pressure by probe is applied which cuts oxygen supply. The cellular respiration causes the observed decrease in oxygen levels. At 38 seconds pressure is released and MitoPO 2 recovers. In the control group 4 participants and in the LPS group 10 out of 12 participants gave sufficient PpIX signal. In the control group, no significant changes in mitoPO 2 or mitoVO 2 were observed throughout the experiment (Fig. 6A and B). In contrast, a significant decrease in mitoPO 2 (median [IQR]) was observed 1.45 hours after LPS administration compared with baseline (61 [53-72] vs. 41.7 [37-51] mmHg, Fig. 6A). Although LPS administration did result in significant changes in mitoVO 2 over time (indicated by a Friedman test p-value < 0.05), post-hoc tests did not reveal statistically significant differences on individual timepoints post-LPS compared with baseline, although an increasing trend was observed at later timepoints (Fig. 6B).