The importance of tumor necrosis factor and lipoproteins in the pathogenesis of chronic heart failure.

Elevated levels of proinflammatory cytokines, such as tumor necrosis factor (TNF) and interleukin-6 (IL-6), have been demonstrated in patients with chronic heart failure (CHF). Evidence suggests that cytokines such as these may play a central role in the pathogenesis of this syndrome. TNF has several properties that are particularly detrimental in CHF, such as negatively inotropic effects, the promotion of left ventricular remodelling, and the induction of dilated cardiomyopathy in humans. Furthermore, TNF can cause skeletal muscle wasting and apoptosis, and, therefore, may be important in the development of cardiac cachexia. Although the precise stimulus for immune activation in CHF is unknown, one hypothesis is that endotoxin may be a significant trigger for cytokine release. This is supported by the finding that decompensated CHF patients have elevated endotoxin levels that normalize on diuretic therapy. The factors that influence endotoxin responsiveness in patients with CHF, in particular the potential importance of serum lipoproteins, will be discussed in this review.