HEPATIC ENERGY AND SUBSTRATE METABOLISM - A POSSIBLE METABOLIC BASIS FOR EARLY NUTRITIONAL SUPPORT IN CIRRHOTIC-PATIENTS

In the liver, the in vivo assessment of metabolic functions is Limited by methodologic problems. The present evidence suggests that the live r contributes to 20-30% of whole body energy expenditure. Hepatic fuel selection can change considerably under different circumstances. Duri ng tissue catabolism (i.e., depletion of glycogen stores, increased li pid oxidation), the ''hepatic respiratory quotient (RQ)'' is lower tha n whole body RQ, suggesting that hepatic catabolism exceeds whole body catabolism. By contrast, the hepatic RQ may exceed whole body RQ duri ng tissue anabolism (i.e., after full repletion of hepatic glycogen st ores and significant lipogenesis). In cirrhosis, both the hepatic RQ a nd the whole body RQ are markedly reduced. When compared with the whol e body level, the cirrhosis-induced decrease in the hepatic RQ is more pronounced. Given that liver catabolism exceeds (or possibly precedes ) whole body catabolism, early nutritional support is mandatory in cir rhotic patients. The assessment of hepatic, in addition to whole body, energy metabolism may provide a basis for future recommendations of m ore specific nutritional support in patients with liver diseases. (C) Elsevier Science Inc. 1998.