New frontiers in the pharmacological prevention of post-ERCP pancreatitis: the cytokines.

Acute pancreatitis is a major complication of endoscopic retrograde cholangiopancreatography (ERCP), its incidence varying with the indications for the procedure (<5% for the management of common bile duct stones and up to 20% in the case of sphincter of Oddi dysfunction) and also with events occurring during the ERCP such as acinarization and pancreatic sphincterotomy. If the triggering event of premature intra-acinar activation of trypsinogen is unknown, the acinar cell injury leads to oxidative stress, nuclear translocation of nuclear factor kappa B and subsequent transcription of chemo- and pro-inflammatory cytokines. These events are followed by chemoattraction and activation of monomacrophages, T lymphocytes and neutrophils which are responsible for acinar necrosis and amplification of the pro-inflammatory cascade. Finally, after amplification by Kupffer cells, systemic inflammatory response syndrome and multiple organ failure occur. All these events take place within a very short period of time, thus offering a very short therapeutic window during which it is theoretically possible to modulate the severity of human pancreatitis. Prophylactic immunomodulation of this pro-inflammatory cascade is attractive, using anti-inflammatory cytokines, specific inhibitors of pro-inflammatory cytokines or inhibitors of the nuclear translocation of the nuclear factor kappa B. Good results have been obtained in experimental models, reducing the acute pancreatitis severity and its systemic complications. The use of immunomodulators in the prevention of human post-ERCP pancreatitis is actually restricted to recombinant interleukin-10. Three of four randomized clinical trials, confirmed by a meta-analysis, have shown that prophylactic injection of recombinant interleukin-10 can significantly reduce the incidence of acute pancreatitis and may decrease the length of the hospital stay. The use of recombinant interleukin-10 in this indication has to be established in a multicenter prospective trial and we need to investigate the safety and efficacy of other immunomodulatory drugs and develop new specific targets.