Nutritional alterations and the effect of fish oil supplementation in dogswith heart failure

Alterations in body composition and nutritional status are common in humans with heart failure and are related, in part, to increases in cytokine conc entrations. Cytokines have not been studied previously in dogs with natural ly occurring cardiac disease nor has fish oil administration been used in t his population to decrease cytokine production. The purposes of this study were to characterize nutritional and cytokine alterations in dogs with hear t failure and to test the ability of fish oil to reduce cytokines and impro ve clinical outcome. Body composition, insulinlike growth factor-1, fatty a cids, and cytokines were measured in 28 dogs with heart failure and in 5 he althy controls. Dogs with heart failure then were randomized to receive eit her fish oil or placebo for 8 weeks. All parameters were measured again at the end of the study period. At baseline, 54% of dogs with heart failure we re cachectic and the severity of cachexia correlated with circulating tumor necrosis factor-alpha concentrations (P = .05). Cytokine concentrations at baseline, however, were not significantly increased in dogs with heart fai lure compared to controls. Baseline plasma arachidonic acid (P = .02), eico sapentaenoic acid (P = .03), and docosahexaenoic acid (P = .004) concentrat ions were lower in dogs with heart failure than in controls. Fish oil suppl ementation decreased interleukin-1 beta (IL-1) concentrations (P = .02) and improved cachexia (P = .01) compared to the placebo group. The mean calori c intake of the heart failure dogs as a group was below the maintenance ene rgy requirement (P < .001), but no difference was found in food intake betw een the fish oil and placebo groups. Insulinlike growth factor-1 concentrat ions (P = .01) and reductions in circulating IL-1 concentrations over the s tudy period (P = .02) correlated with survival. These data demonstrate that canine heart failure is associated with cachexia, alterations in fatty aci ds, and reduced caloric intake. Fish oil supplementation decreased IL-1 con centrations and improved cachexia. In addition, reductions in IL-1 predicte d survival, suggesting that anticytokine strategies may benefit patients wi th heart failure.