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The nisms by which these metabolic disturbaes occur are not fully understood; however, several factors have been identified which are able to mimic the effects of cachexia ecperimentally. In generaL inflammatory cytokines have been shown to play a major role in the alterations in metabolism seen in these disease states. Tumour necrosis factor-a (TNFa), interleukin-1 (IL-10), interleukin-6 (IL-6) and interferons-a and -7 have all been shown to increase hepatic lipogenesis and serm triglyceride levels (Feingold and GrunfeKl, 1987;Grunfeld et al., 1988Grunfeld et al., , 1991Darling et al., 1990;Feingold et al., 1991; Blackham et al., 1992; Ettinger et al., 1992;Furlong et al., 1992;Arias-Diaz et al., 1993;Memon et al., 1993; Stassman et al., 1993), and in some cases reduce triglyceride ckarance (Beutler et al., 1985;Noguchi et al., 1991). Antibodies to these cytokines have been shown to ameliorate the effects on lipid metabolism when sepsis is experimentally induced by injection of lipopolysaccharide (LPS) in animals (Tracey et al., 1987;Memon et al., 1993; Strassman et al., 1993), and in cachexiainducing tumour models (Sherry et al., 1989; Lgstein et al., 1991), demonstrating that alterations in lipid metabolism as a result of diwase are ideed mediated at least in part by inflammatory cytokines. Further, circulating wles of cytokines have been demonstrated to be elevated in AIDS (Gunfeld and Feingol 1992a,b), some forms of cancer (Balkwill et al., 1987;Jablons et al., 1989;Stovroff et al., 1989) and sepsis (Fong et al., 1990) al., 1990), and inhibitors of the synthesis of prostaglandin and platelet-activating factor (Welbourn and Young, 1992) but none has been completely successful in altering metabolc imbalances or increasng survival. Because of the well-known role of L-carmtie as a carrier of long-chain fatty acids into the mitochondrial matrix for oxidation (for review, see Bremer, 1983), it has recently been hypotheised that administration of carnitine to septic or cachectic patients could increase the rate of oxidation of fatty acids and normalise lid metabolism. Carnitine administration has been shown to rele the symptoms of carniine-deficient humans (Worthley et al., 1983) and increase the survival of endotoxic rats (Takeyama et al., 1989). This laboratory recently demonstrated that carnitine administration to LPS-injected rats increased survival and food consumption, and decreased plasma triglycerides and hepatic lipogenesis (Gabo et al., 1993). Mehanisms of carnitie effects in sepsis are still unknown, as in vitro rates of oxidation in isolated mitochondria from livers of LPS-injected rats were not increased by in vivo administration of carnitine.In the studies presented in this paper, we investigated whether carnitine had an effect on the level of inflammatory cytokines which are generally increased in sepsis and cachexia and are known to affect lipid metabolism. We uilised both an LPS-induced model of septic shock in rats (Takeyama et al., 1989;Gallo et al., 1993) and a rat methykholanthreneind...

Background-Tissue-engineered or decellularized heart valves have already been implanted in humans or are currently approaching the clinical setting. The aim of this study was to examine the migratory response of human monocytic cells toward decellularized porcine and human heart valves, a pivotal step in the early immunologic reaction. Methods and Results-Porcine and human pulmonary valve conduits were decellularized, and migration of U-937 monocytic cells toward extracted heart valve proteins was examined in a transmigration chamber in vitro. Homogenized tissue specimens were size fractionated by SDS-PAGE. ). SDS-PAGE of the pulmonary heart valve tissue revealed that considerable amounts of proteins with different molecular weights that were not detected in the human equivalent remain in the decellularized porcine heart valve. Conclusions-We describe for the first time that the remaining potential of decellularized pulmonary heart valves to attract monocytic cells depends strongly on whether porcine or human scaffolds were used. These findings will have an important impact on further investigations in the field of heart valve tissue engineering.

Cigarette smoking is one of the most important and preventable risk factors for atherosclerosis. However, because of the complex composition of cigarette smoke, the detailed pathophysiological mechanisms are not fully understood. Based on controversial reports on the pro-atherogenic activity of cigarette smoke condensate, also called tar fraction (CSC), we decided to analyse the effects of CSC on the viability of endothelial cells in vitro. The results of this study show that low concentrations of the hydrophobic tar fraction induces DNA damage resulting in a P53-dependent and BCL-XL-inhibitable death cascade. Western blot analyses showed that this cascade is caspase-independent and immunofluorescence analysis have shown that the apoptotic death signalling is mediated by the release of apoptosis-inducing factor. Higher CSC concentrations also induce apoptotic-like signalling but the signalling cascade is then redirected to necrosis. Despite the fact that CSC induces a profound increase in cellular reactive oxygen species production, antioxidants exhibit only a minimal cell death protective effect. Our data indicates that not only hydrophilic constituents of cigarette smoke extract, but also CSC is harmful to endothelial cells. The mode and the outcome of CSC-induced cell death signalling are highly concentration dependent: lower concentrations induce caspase-independent apoptosis-like cell death, whereas incubation with higher concentrations interrupts apoptotic signalling and induces necrosis.