Mark Wefers Bettink

Measuring mitochondrial oxygenation and respiration in vivo in a human endotoxemia model 6 109 Study procedures In both the endotoxemia and time-control protocols, subjects refrained from consuming caffeine or alcohol 24 hours before the start of the experiment, and from food 10 hours before the start of the experiment. An ALAcare 8mg plaster (Photonamic GmbH & Co KG, Wedel, Germany) was applied 8-10 hours before the first mitochondrial respiration measurement with the COMET (off-label use approved by the institutional review board). At the end of the experiment, the measurement site was covered by a plaster to prevent exposure to light for a day. The following morning, debriefing of the volunteers followed with attention to possible side effect of LPS and the plaster. A schematic overview of the procedures is provided in Fig. 1. Fig. 1. Schematic overview of the experimental procedures. After fasting for 10 hours, subjects were prehydrated during 1 hour before administration of LPS (LPS group) or no administration (control group). Mitochondrial respiration and blood gas parameters were measured at 4 time points during the experiment. The x-axis represents hours relative to LPS/no LPS administration. In the endotoxemia protocol, purified LPS (Clinical Center Reference Endotoxin derived from Escherichia coli O:113, obtained from Pharmaceutical Development Section of the National Institutes of Health (Bethesda, MD, USA)) supplied as a lyophilized powder, was reconstituted in 5 mL saline 0.9% for injection and vortex mixed for at least 20 min after reconstitution. The LPS solution was administered as an i.v. bolus injection at a dose of 2 ng/kg body weight in 1 min at T 0 . In both protocols, a cannula was placed in an antecubital vein to permit infusion of 2.5% glucose / 0.45% solution; all subjects received 1.5L 2.5% glucose / 0.45% saline during 1 hour, starting 1 hour before T 0 (prehydration) as part of the standard endotoxemia protocol [12], followed by 150 mL/h for 6 hours and 75ml/h until completion of the experiment. All the volunteers remained in bed during the entire experiment. Baseline COMET measurements were performed before the start of prehydration. Heart rate (three-lead electrocardiogram), blood pressure, and oxygen saturation (pulse oximetry)