Prostaglandin E2 as a Mechanistic Biomarker of Chronic Pancreatitis

INTRODUCTION: Chronic pancreatitis (CP) is a disease associated with chronic inflammation, fibrosis, and pain. There is a lack of tools available that facilitate early diagnosis, when intervention could prevent irreversible damage. Pilot data suggested prostaglandin E2 (PGE2) as a candidate biomarker for early CP. PGE2 activates signaling pathways that promote inflammation, pain, and fibrosis. METHODS: We assessed PGE2, metabolites, and downstream targets in pancreatic fluid collected endoscopically 0–10 (n = 110) and 10–20 (n = 111) minutes after intravenous secretin administration. PGE2 and metabolites were measured in plasma (n = 75) and urine (n = 71) from the same subjects. Subjects were enrolled in the PROCEED study and classified symptomatic controls, acute/recurrent acute pancreatitis (AP/RAP), or CP. RESULTS: A significant main effect was detected in 10–20 minutes pancreas fluid ( P = 0.027) and plasma ( P = 0.046); post hoc testing showed PGE2 was lower in the AP/RAP group compared with symptomatic controls. There was also trend toward lower PGE2 in urine ( P = 0.062). To elucidate the active downstream pathways, calcitonin gene-related peptide, substance P, and matrix metalloproteinases (MMPs) 1, 2, 3, 7, 9, and 13 were measured in pancreas fluid. A significant difference between the 3 groups was detected for both MMP7 and MMP9. MMP7 was elevated in individuals with CP vs AP/RAP ( P = 0.012) for samples collected early but both time points for MMP9 ( P = 0.027, P = 0.002). DISCUSSION: While PGE2 is detectable in pancreas fluid, these data suggest that it may not be sensitive enough to distinguish between AP/RAP and CP. However, MMPs may distinguish between stages of pancreatitis and require further testing as potential diagnostic biomarkers.