METHIONINE-ENKEPHALIN CONCENTRATIONS CORRELATE WITH STAGE OF DISEASE BUT NOT PRURITUS IN PATIENTS WITH PRIMARY BILIARY-CIRRHOSIS

Objective: Opiate antagonist agents ameliorate pruritus in some patien ts with cholestatic liver disease, suggesting that endogenous opioids may mediate pruritus in cholestasis. However, the endogenous opioids p otentially responsible for pruritus remain unknown. Methionine-enkepha lin is an endogenous opioid synthesized in numerous tissues including the gastrointestinal tract, and released into the portal circulation. Serum methionine-enkephalin concentrations are elevated in patients wi th chronic liver disease, making this opioid a candidate for opioid-me diated pruritus in cholestatic liver disease. The aim of our study was to determine whether elevated circulating methionine-enkephalin conce ntrations are associated with pruritus. Methods: Serum concentrations of methionine-enkephalin were measured in 54 consecutive, untreated pa tients with primary biliary cirrhosis and 20 healthy controls. There w as a direct correlation between methionine-enkephalin concentrations a nd total serum bilirubin (r = 0.42, p < 0.05) and the Mayo risk score (r = 0.5, p < 0.005). Methionine-enkephalin concentrations were signif icantly higher in histological stages 3 and 4 (48 +/- 4 pg/ml, n = 44) , compared with stages 1 and 2 (29 +/- 12 pg/ml, n = 10, p < 0.05). Me thionine-enkephalin concentrations in both histological groups were si gnificantly higher than those in 20 healthy controls (16 +/- 4 pg/ml, p < 0.005). Results: There was no significant correlation between meth ionine-enkephalin concentrations and the presence of pruritus (46 +/- 25 pg/ml with pruritus vs. 40 +/- 22 pg/ml without pruritus, n = 20). Conclusions: Increased serum methionine-enkephalin concentrations in p atients with primary biliary cirrhosis were not associated with prurit us.