Tissue concentrations of vasoactive intestinal peptide are affected by peritonitis-induced sepsis and hemofiltration...

Vasoactive intestinal peptide (VIP) is a neuropeptide released from the autonomic nerves exerting multiple antiinflammatory effects. The aim of the present study was to investigate the impact of severe sepsis and hemofiltration in two settings on plasma and tissue concentrations of VIP in a porcine model of sepsis. Thirty-two pigs were divided into 5 groups: 1) control group; 2) control group with conventional hemofiltration; 3) septic group; 4) septic group with conventional hemofiltration; 5) septic group with high-volume hemofiltration. Sepsis induced by faecal peritonitis continued for 22 hours. Hemofiltration was applied for the last 10 hours. Hemodynamic, inflammatory and oxidative stress parameters (heart rate, mean arterial pressure, cardiac output, systemic vascular resistance, plasma concentrations of tumor necrosis factor-alpha, interleukin-6, thiobarbituric acid reactive species, nitrate + nitrite, asymmetric dimethylarginine) and the systemic VIP concentrations were measured before faeces inoculation and at 12 and 22 hours of peritonitis. VIP tissue levels were determined in the left ventricle, mesenteric and coronary arteries. Sepsis induced significant increases in VIP concentrations in the plasma and mesenteric artery, but it decreased peptide levels in the coronary artery. Hemofiltration in both settings reduced concentrations of VIP in the mesenteric artery. In severe sepsis, VIP seems to be rapidly depleted from the coronary artery and, on the other hand, upregulated in the mesenteric artery. Hemofiltration in both settings has a tendency to drain away these upregulated tissue stores which could result in the limited secretory capacity of the peptide.