Role of hyaluronan in acute pancreatitis

Background. The connective tissue component hyaluronan is accumulated local ly in the damaged tissue during various inflammatory conditions. Owing to t he strong water-binding capacity of this glycasaminoglycan, inn-eased tissu e content of hyaluronan Is paralleled by the development of interstitial ed ema. The aim with the current experiment was to investigate whether hyaluro nan is accumulated in acute pancreatitis and if increased levels of hyaluro nan can be correlated to the inflammation of the pancreatic tissue. Methods. Acute pancreatitis was induced in Sprague-Dawley mts by the admini stration of supramaximal doses of the cholecystokinin analogue caerulein. T he animals were followed for 5 hours (n = 4), 24 hours (n = 4), or 48 hours (n = 5), and the pancreata were then investigated for hyaluronan and water content, hyaluronan distribution, general morphology and the presence of C D44-positive cells, macrophages, and T lymphocytes. Results. Hyaluronan accumulated in the edematous interstitium during acute pancreatitis. Twenty-four hours after the induction of pancreatitis, the hy aluronan content of the pancrenta had increased by more than 100%. Simultan eously, CD44-positive cells infiltrated the tissue. However no correlation between hyaluronan and water was seen at any time point. Conclusions, This study shows that acute pancreatitis is associated with a strong but transient increase in interstitial hyaluronan and an infiltratio n of CD44-positive cells located mainly in the same region as the accumulat ed hyaluronan.