Biomarkers and pathogenesis of Alcoholic acute pancreatitis

PROJECT SUMMARY Acute pancreatitis (AP) affects 270,000 patients/ year in the USA. Alcoholic AP (AAP) is difficult to diagnose due to under-reporting and lack of a reliable biomarker, with 5-70% of AP being reported as AAP. Alcohol is not a good biomarker and is detected in only 20% of AAP cases. Phosphatidyl ethanol (PEth), a membrane phospholipid rapidly formed in the presence of ethanol, is found in blood cells. PEth reflects alcohol intake but may be unaffected by AAP associated inflammation. However, fatty acids ethyl esters (FAEEs) found in the fat and pancreas of alcoholics may be excellent AAP biomarkers since FAEEs increase in AAP without detectable alcohol. Moreover, serum FAEEs >18 nM (normal 2099nM, may predict severe AAP better than the established criteria. Since human AP universally has visceral fat necrosis, we HYPOTHESIZE that: FAEEs released from fat necrosis can diagnose AAP, predict its severity, and may worsen the course of AAP. To test this, Aim 1 will validate FAEEs as biomarkers for AAP. In aim 1A: we will determine the utility of FAEEs as diagnostic biomarkers of AAP. While NEFA increase only 2-4-fold during AP; the large FAEE increase early in severe AAP may occur in patients with elevated blood alcohol and predict AAP severity. Thus, aim 1B will study if FAEEs are prognostic markers for severe AAP. Aim 2 will Determine FAEE’s in relation to alcohol intake, fatty acid composition, AP etiology and severity. Aim 2A will determine FAEE’s relation to alcohol intake, fatty acid composition in humans without AP. Our preliminary studies show FAEE concentrations in the fat of alcoholics without AP are ≈1/10th those of AAP patients. Therefore, Aim 2B will Determine FAEEs in VFN, their relation to AP etiology and NEFA composition. To understand if FAEEs make AP severe independent of alcohol and fatty acid generation; Aim 2C will determine the impact of alcohol and FAEEs on AP severity in mice. since alcohol increases NEFA induced injury in multiple cell types and also FAEE induced organ failure; Aim 3 will determine the mechanisms by which alcohol increases NEFA and FAEE mediated injury in AAP. Here we will examine the roles of alcohol mediated aqueous stability of fatty acids (Aim 3A) and PEth generation (Aim 3B) in severe AAP. For this we will use physical chemistry methods to study whether alcohol increases stability of the normally hydrophobic NEFA or FAEE monomers, which have long (12-18 carbon) acyl chains. We will also study whether alcohol, or PEth generation via phospholipase D2 increase an amphipathic interaction between these acyl chains and cell membrane phospholipids of pancreatic acini, adipocytes and endothelial cells that re injured during AAP. This is based on a novel interaction responsible for NEFA (and perhaps FAEE) uptake into cells which causes cell injury. This uptake that can be followed by novel live imaging methods using coumarin tagged NEFA. Overall, this proposal explores FAEEs as diagnostic and prognostic markers for alcoholic AP and explains how alcohol- lipid interactions affect the disease course.