Dexamethasone and recombinant human activated protein C improve myocardial function and efficiency during experimental septic shock.

Abstract

Corticosteroids have been shown to reduce short-term mortality during septic shock and therefore recommended in the most severe patients as adjuvant therapy. Until recently, recombinant human activated protein C (APC) was also considered in the management of more severe cases. As myocardial depression has long been recognized as a manifestation of organ dysfunction during septic shock, we examined whether corticosteroids (dexamethasone, 150 µg/kg per hour) and/or APC (33 µg/kg per hour) treatments improve sepsis-induced cardiac dysfunction during cecal ligature and puncture-induced septic shock in Wistar rats. All rats received intravenous saline resuscitation (10 mL/kg per hour) and antibiotics. Eighteen hours after surgery, anesthesia was performed (isoflurane), and myocardial function was assessed using a conductance catheter introduced into the left ventricle. Rats were then killed; blood and heart were harvested for biological analysis, including radical oxygen species determination. Cecal ligature and puncture induced hypotension, depression of myocardial systolic performance (demonstrated by significant decreases in dP/dtmax [first derivative of maximal developed pressure during isovolumetric contraction], end-systolic pressure-volume relationship, and preload recruitable stroke work) and alteration of diastolic function (dP/dtmin [first derivative of minimal developed pressure during isovolumetric relaxation]), whereas dexamethasone, APC, and their combination thereof allowed correction of hemodynamic disorders and improved myocardial mechanical efficiency. Cecal ligature and puncture was associated with higher levels of nitric oxide and superoxide anion (O2) in heart (electron paramagnetic resonance studies) and consequently peroxynitrite. Dexamethasone and APC also improved cardiac dysfunction by downregulating the inducible nitric oxide synthase pathway and reducing myocardial oxidative stress.