Complement depletion with Naje haje cobra venom factor limits prostaglandin release and improves visceral perfusion...

We tested the hypothesis that complement (C')-dependent release of prostaglandin (PG) I2 is an important factor contributing to the development of hypotension and low systemic vascular resistance index (SVRI) in endotoxic shock. Two groups (n = 7) of pentobarbital-anesthetized pigs (12-15 kg) were infused over 40 min with Escherichia coli lipopolysaccharide (LPS; 200 micrograms/kg) and continuously resuscitated with normal saline (1 ml/kg min): LPS-Control (no pretreatment) and LPS-Decomplemented (pretreatment 18 hr before study with 500-1,500 units of Naje haje cobra venom factor, CVF). Prior treatment with CVF: i) decreased the mean titer of total hemolytic C' to 15.9% of pretreatment levels; ii) significantly decreased post-LPS plasma concentrations of immunoreactive TxB2 (TxA2 metabolite) and 6-keto-PGF1 alpha (PGI2 metabolite); iii) abrogated the early transient decrease in cardiac index observed in the LPS-Control group; iv) tended to improve post-LPS visceral perfusion assessed using radioactive microspheres; and v) had no discernible effect on the late sustained decrease in SVRI observed following infusion of LPS. We conclude that C' activation is a major determinant of LPS-induced prostanoid release in vivo, although our results do not support the view that C'-dependent release of PGI2 is an important factor contributing to low SVRI in resuscitated endotoxic shock.