The role of heme in hemolysis-induced acute pancreatitis.

BACKGROUND The aim was to reveal the mechanism of hemolysis-induced acute pancreatitis and to evaluate the role of heme and heme oxygenase activity in inducing pancreatic inflammation in an experimental hemolysis model. MATERIAL/METHODS Hemolytic anemia was induced in rats by intraperitoneal injection of 60 mg/kg acetylphenylhydrazine (APH). To evaluate the toxic effect of free heme after hemolysis, heme oxygenase inhibitor (HOI) was used to inhibit the enzyme which decreases the free heme concentration after hemolysis. One hundred and fifty rats were divided into two treatment and three control groups. Rats in the hemolysis group were given APH intraperitoneally. Rats in the HOI+hemolysis group were given Cr(III)mesoporphyrin IX chloride as HOI and then APH intraperitoneally. Serum amylase and lipase levels as well as pancreatic tissue cytokine content were determined and histological examination performed. RESULTS No hemolysis or pancreatitis was seen in the control groups. Massive hemolysis was seen in 22 of the 30 rats of the hemolysis group and 20 of the 30 rats of the HOI+hemolysis group. The total pancreatitis rates were 60% and 76.6% in the hemolysis and HOI+hemolysis groups, respectively (p<0.05). Pancreatic cytokine levels were significantly higher in the HOI+hemolysis and hemolysis groups than in all control groups. The highest ICAM-1 and MCP-1 levels were in the HOI+hemolysis group. Histological signs of acute pancreatitis were also more severe in this group. CONCLUSIONS Acute massive hemolysis can induce acute pancreatitis. Excess of free vascular heme seems to be an inducer of inflammation by modulating ICAM-1 and MCP-1.