Background: Fulminant acute pancreatitis is a disease of complex origin that results in activation of several of the proinflammatory cytokines. Because interleukin-1 (IL-1) is an integral early component of the acute inflammatory process, the use of an IL-1 receptor antagonist (IL-1ra) was investigated in experimental acute pancreatitis to determine the therapeutic potential of proximal cytokine blockade and to further establish the role of inflammatory cytokines in the pathogenesis of acute pancreatitis.
Methods: IL-1ra was administered in escalating doses either before or after acute edematous, necrotizing pancreatitis was induced in adult male mice by injection of cerulein. The severity of pancreatitis was quantified by serum amylase, lipase, interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-alpha) levels, pancreatic wet weight, and blinded histologic grading.
Results: Administration of medium (10 mg/kg) and high (100 mg/kg) doses of IL-1ra either before or after the induction of pancreatitis significantly decreased the expected rise in pancreatic wet weight, lipase, IL-6, and TNF-alpha (all, p < 0.01). Serum amylase was significantly reduced when IL-1ra was administered in either dosage before (p < 0.05), but not after, induction of pancreatitis. Pancreatic edema, necrosis, and inflammatory cell infiltrate were significantly diminished (p < 0.05) by histologic grading in all animals receiving medium or high doses of IL-1ra. Low doses of IL-1ra (1.0 mg/kg) had modest effects if given before, but no effect if given after, induction of pancreatitis.
Conclusions: The proinflammatory cytokines IL-6 and TNF-alpha are elevated during experimental acute pancreatitis and correlate well with the severity of local pancreatic destruction. Blockade of the cytokine cascade at the level of the IL-1 receptor before or soon after induction of pancreatitis significantly attenuates the rise in these cytokines and is associated with decreased severity of pancreatitis and reduced intrinsic pancreatic damage.