Fatty acid metabolism in renal ischemia

The increase in free fatty acids in the ischemic tissue is a consistent observation and these free fatty acids are considered to play a role in the cellular toxicity. To elucidate the cause of higher levels of free fatty acids in ischemic tissue, we examined the catabolism of fatty acids. The beta-oxidation of lignoceric (24:0), palmitic (16:0) and octanoic (8:0) acids and the peroxidation of fatty acids were measured at different times of renal ischemia in whole kidney homogenate. The enzymatic activities for the oxidation of fatty acids decreased with the increase in ischemia time. However, the lipid peroxide levels increased 2.5-fold of control with ischemic injury. Sixty min of ischemia reduced the rate of oxidation of octanoic, palmitic and lignoceric acids by 57, 59 and 69%, respectively. Almost similar loss of fatty acid oxidation activity was observed in the peroxisomes and mitochondria. These data suggest that loss of mitochondrial and peroxisomal fatty acid beta-oxidation enzyme activities from ischemic injury may be one of the factors responsible for the higher levels of free fatty acids.