Nicotinamide increases systemic vascular resistance in ovine endotoxemia.

Objective: The nuclear enzyme Poly(ADP-Ribose)-Polymerase (PARP) has been hypothesized as playing a major role in various forms of inflammation. PARP activation is induced by DNA strand breakage and can result in intracellular energy depletion and, ultimately, cell death. Further, it is thought to influence cardiovascular function and organ failure in endotoxemia. Here, we investigated the effect of the PARP inhibitor nicotinamide on cardiovascular and liver function in healthy and chronically endotoxemic sheep.

Design: Prospective controlled trial.

Setting: University research laboratory.

Subjects: 12 female adult sheep.

Interventions: Six healthy sheep, instrumented for chronic study, received nicotinamide intravenously as a bolus of 40 mg/kg followed by a continuous infusion of 10 mg.kg(-1).h(-1); six animals received the vehicle. One hour after bolus application, a continuous infusion of endotoxin ( Salmonella typhosa, 10 ng.kg(-1).min(-1)) was started. Hemodynamic parameters were determined before and during endotoxemia.

Measurements And Results: Treatment with nicotinamide resulted in a significantly higher systemic vascular resistance index and lower cardiac index in endotoxemic animals, but not in controls. It also attenuated endotoxin-induced increase in gamma-glutamyl transferase.

Conclusions: The PARP inhibitor nicotinamide attenuates impairment of cardiovascular function during endotoxemia. In addition, PARP activation may be involved in endotoxin-induced liver injury.