Associations between Intra-Pancreatic Fat Deposition, Pancreas Size, and Pancreatic Enzymes in Health and after an Attack of Acute Pancreatitis

INTRODUCTION Ectopic fat deposition in the pancreas is involved in the pathogenesis of metabolic sequelae following an attack of pancreatitis. However, its relationship with the exocrine pancreas has never been explored in this setting. The aim was to investigate the associations between intra-pancreatic fat deposition (IPFD), pancreas size, and pancreatic enzymes. METHODS This cross-sectional study recruited individuals with a history of acute pancreatitis and healthy controls. All participants underwent 3T magnetic resonance imaging, from which IPFD, total pancreas volume (TPV), and pancreas diameters (across the head, body, and tail) were measured independently by 2 raters in a blinded fashion. Circulating levels of pancreatic amylase, pancreatic lipase, and chymotrypsin were measured in a fasted state. A series of linear regression analyses was conducted, accounting for possible confounders. RESULTS A total of 108 individuals with pancreatitis and 60 healthy controls were studied. There was a statistically significant difference in IPFD (p < 0.001), but not in TPV (p = 0.389), between the groups. In the post-pancreatitis group, IPFD was significantly inversely associated with pancreas tail diameter (β = -0.736, p = 0.036 in the most adjusted model). In the control group, IPFD was significantly inversely associated with TPV (β = -3.557, p = 0.026 in the most adjusted model). Levels of pancreatic amylase were significantly directly associated with pancreas tail diameter in the post-pancreatitis group (β = 3.891, p = 0.042 in the most adjusted model), whereas levels of pancreatic lipase were significantly inversely associated with TPV in the control group (β = -10.533, p = 0.024 in the most adjusted model). CONCLUSION Increased IPFD in individuals after an attack of pancreatitis is associated with reduced pancreas tail diameter, which is in turn associated with reduced circulating levels of pancreatic amylase. The relationship between IPFD and the exocrine pancreas warrants further investigations.