Is zinc concentration in pancreatic fluid a marker for pancreatic diseases?

OBJECTIVES An imbalance of free radicals and scavenging processes has been implicated in the pathogenesis of pancreatic tissue injury. Gradual decreases in antioxidant enzyme expression in pancreatic cells from normal pancreas to chronic pancreatitis to pancreatic cancer have been reported. Zinc is one of the components of antioxidant enzymes and may play a role in the pathogenesis of pancreatic diseases. A recent report showed a significant decrease in pancreatic zinc output in patients with chronic pancreatitis and proposed that zinc output can be used as an alternative to enzyme output for the diagnosis. We aimed to determine the zinc concentration in pancreatic fluid of patients with chronic pancreatitis and pancreatic cancer compared to normal pancreas. PATIENTS Seventy-five consecutive patients were prospectively evaluated. Chronic pancreatitis was diagnosed in 20 patients by ERCP (n=16) and histology (n=4). Pancreatic cancer was diagnosed in 17 patients by cytology from EUS-FNA (n=12) or surgical pathology (n=5). Thirty-eight patients were confirmed to have normal pancreas. INTERVENTIONS Patients underwent esophagogastroduodenoscopy following intravenous secretin injection (0.2 microg/kg). Pancreatic fluid collected for 10 minutes was immediately frozen at -80 degrees C and stored until the assay was performed. MAIN OUTCOME MEASURE Zinc concentrations were determined by inductively coupled plasma optical emission spectroscopy. RESULTS Among the three groups, patients with pancreatic cancer were significant older (P<0.001) with a higher prevalence of diabetes mellitus (P=0.002). Gender distribution (P=0.098), body mass index (P=0.925), and history of alcohol use (P=0.997) were similar among groups. Zinc concentrations in pancreatic fluid were not significantly different among groups (P=0.129). CONCLUSIONS Zinc concentration in pancreatic fluid was comparable in patients with chronic pancreatitis and pancreatic cancer compared to normal pancreas. Zinc concentration in pancreatic fluid collected by our 10-minute endoscopic method cannot reliably be used for the diagnosis of chronic pancreatitis and/or pancreatic cancer.