This is a mono-center randomized controlled trial to be performed in the Center of Medical Research (ZMF) at Medical University Graz and is composed by one screening visit (V1) and two study visits (V2 and V3). In the visit V1, complete medical examination will be performed and blood samples will be withdrawn to check overall conditions of the healthy volunteers. Those who accomplish the necessary conditions will be enrolled in the trial to receive either saline or lipid-heparin solutions in a randomized, cross-over design during visits V2 and V3. Volunteers will arrive at ZMF after overnight fasting, when two venous catheters will be placed in forearm veins. One venous catheter will be used for continuous infusion of lipid-heparin solution (Intralipid 20%, 40 ml/h, Fresenius Kabi plus Heparin 250U/h, IMMUNO Baxter AG) or saline, and Inulin (Inutest 25%, Fresenius Kabi). The second venous catheter will be used for blood sampling (arterialized venous blood). Subsequently, two open flow microperfusion (OFM) macro-perforated catheters will be inserted in the subcutaneous tissue of abdominal wall for continuous sampling of interstitial fluid. Study visits will last for 28 hours for continuous sampling, with four additional hours for observation after infusion discontinuation, during visits V2 and V3. Concentrations of different cytokines, non-esterified fatty-acids, insulin, glucose, triglycerides and inulin will be retrospectively quantified in the frozen samples.

The primary hypothesis is that cytokine concentrations in subcutaneous tissue and/or in circulation can be modified by lipid-heparin infusion.