Acute portal hypertension increases ileal vulnerability to platelet-activating factor in rats

Background. Patients with portal hypertension can easily develop sepsis of enteric origin after suffering severe trauma and hemorrhagic shock. Platele t-activating factor (PAF) is one of the key mediators of such stress. The a im of this study was to investigate whether portal hypertension increases t he vulnerability of the ileum to PAF. Materials and methods. Seven days after surgery, PAF (1.5 mu g/kg) was intr avenously injected into portal stenosis (PS) rats and sham-operated rats. T he levels of tumor necrosis factor-alpha (TNF-alpha), cytokine-induced neut rophil chemoattractant (CINC), and endotoxin in portal plasma were determin ed. The levels of PAF receptor (PAFR), TNF-alpha, and CINC mRNA in the ileu m were also investigated. Results. After PAF administration, PS rats showed (1) significantly higher portal plasma levels of TNF-alpha, CINC, and endotoxin; (2) higher histolog ical damage scores in the ileum; (3) more infiltrating neutrophils in the i leum; and (4) a significantly higher mortality rate than sham-operated rats (P < 0.01). However, PAFR mRNA levels were similar in the two groups. The CINC mRNA level in the ileum of PS rats was increased from 1 to 4 h after P AF administration, while that of the sham-operated rats was transiently inc reased at 1 h. Conclusions. Portal hypertension increases the vulnerability of the ileum t o PAF. These findings suggest that conditions which causes PAF production m ay be dangerous in patients with portal hypertension. (C) 1999 Academic Pre ss.