Decreased lipolytic activity in tissues during infectious and inflammatory stress

The clearance rate of endogenous and exogenous circulating lipids during the septic or inflammatory state remains a controversial subject. Thus, we have developed rat models of gram-negative and gram-positive sepsis and of sterile inflammation to study this problem. In addition to the febrile response, these stresses induced some of the following metabolic changes in the blood: decreased total protein, albumin, and ketone body levels and increased lactate, pyruvate, alanine, cholesterol, and triacylglycerol levels. The activities of heart, diaphragm, and adipose tissue lipoprotein lipase and of hepatic lipase decreased to differing extents depending on whether the enzyme substrate was a long-chain or a medium- and long-chain triglyceride-based emulsion. However, the latter emulsion was always hydrolyzed faster than the former. This observation suggests that, during infection/inflammation, the medium- and long-chain triglyceride-based emulsion would be cleared more quickly, would induce less hypertriglyceridemia, and would thus deliver lipid energy more rapidly than a traditional long-chain triglyceride-based emulsion.