Elevated VIP and endotoxin plasma levels in human gram-negative septic shock.

Vasoactive intestinal polypeptide (VIP) and endotoxin (lipopolysaccharides, LPS) were measured in plasma samples from 11 patients with bacteriologically verified meningococcal disease. Five patients suffered fulminant septicaemia, developed severe septic shock, and 2 died due to circulatory collapse. Initially, all 5 had levels of VIP above 4 pM and plasma endotoxin above 200 ng/liter. Five patients were diagnosed as meningitis and 1 as having meningococcaemia, all with a normal circulatory state. None of these 6 patients had initially levels of VIP above 2.5 pM or endotoxin levels above 25 ng/liter (P less than 0.001). A correlation existed between plasma endotoxin and VIP levels (r = 0.735, P = 0.01). Sequentially collected samples from 3 patients showed rapidly declining VIP levels after initiation of antibiotic and fluid treatment. These results are in agreement with previous animal experiments, suggesting that endotoxin directly or indirectly stimulates the VIP-ergic nervous system in the initial phase of gram-negative septic shock in man.