Hyperplasia of fat-containing cells with mature adipocyte marker is associated with pancreatic fat enlargement

Abstract

Abstract Objectives: The purpose was to elucidate the specific characteristics of fat-containing cells in the pancreas and the mechanism of intra-pancreatic fat deposition (IPFD) in humans. Methods: 15 Japanese patients who had undergone pancreatic resection were enrolled and the normal region of pancreatic samples from each patient was examined. To evaluate the characteristics of fat-containing cells, immunostaining for adiponectin and perilipin 1 was performed and the relationships between the pancreatic fat-cell area or clinical parameters, and the density or the diameter of the fat cells was analyzed. Results: Expression of adiponectin in the cytoplasm and perilipin 1 along the plasma membrane were observed in fat-containing cells in the pancreas. The fat-containing cell area had a significant positive correlation with cell density (r = 0.58, p = 0.023). In addition, fat-containing cell density was significantly positively correlated with homeostasis model assessment insulin resistance (HOMA-IR) (r = 0.61, p = 0.045). Fat-containing cell area was not significantly correlated with cell diameter (r = 0.45, p = 0.095). The diameter of fat-containing cells had significant positive correlations with BMI (r = 0.79, p < 0.001), fasting immunoreactive insulin (r = 0.65, p = 0.029) and HOMA-IR (r = 0.80, p = 0.003). Of all fat-containing cells, 10.4% were intralobular cells, and the diameter of intralobular cells showed a tendency for positive correlation with age (r = 0.52, p = 0.057). Conclusions: The characteristics of fat-containing cells in the pancreas indicate that some of them may be mature adipocytes, and fat volume may be increased by hyperplasia of fat-containing cells associated with insulin resistance. Key terms: pancreatic fat, adipocytes markers, hyperplasia of fat-containing cells, insulin resistance.