Relationship of high-density lipoprotein subfractions and apolipoprotein A-I with fat in the pancreas.

AIM: To investigate the associations of high-density lipoprotein (HDL) subfractions and apolipoprotein A-I (apo A-I) with fat in the pancreas. METHODS: A total of 170 individuals were studied. All participants underwent magnetic resonance imaging on a single 3.0-Tesla scanner to determine the presence/absence of fatty pancreas. HDL subfractions were measured using a commercially available lipoprotein subfractions testing system and classed as large, intermediate and small HDL. Both unadjusted and adjusted (accounting for demographics, anthropometrics, insulin resistance and other covariates) logistic regression models were built. RESULTS: Individuals with fatty pancreas had significantly lower circulating levels of the large HDL class and apo A-I. Every unit decrease in the large HDL class was associated with a 93% increase in the likelihood of fatty pancreas in the most adjusted model (P < .001). Every unit decrease in apo A-I was associated with a 45% increase in the likelihood of fatty pancreas in the most adjusted model (P = .012). The intermediate and small HDL classes were not significantly associated with fatty pancreas. CONCLUSIONS: Fat in the pancreas is inversely associated with the circulating levels of large HDL particles and apo A-I. Purposely designed studies are warranted to investigate the potential of fatty pancreas as an indicator of the risk of cardiovascular diseases.

Metabolic traits affecting the relationship between liver fat and intrapancreatic fat: a mediation analysis.

AIMS/HYPOTHESIS: The clinical importance of fat deposition in the liver and pancreas is increasingly recognised. However, to what extent deposition of fat in these two depots is affected by intermediate variables is unknown. The aim of this work was to conduct a mediation analysis with a view to uncovering the metabolic traits that underlie the relationship between liver fat and intrapancreatic fat deposition (IPFD) and quantifying their effect. METHODS: All participants underwent MRI/magnetic resonance spectroscopy on the same 3.0 T scanner to determine liver fat and IPFD. IPFD of all participants was quantified manually by two independent raters in duplicate. A total of 16 metabolic traits (representing markers of glucose metabolism, incretins, lipid panel, liver enzymes, pancreatic hormones and their derivatives) were measured in blood. Mediation analysis was conducted, taking into account age, sex, ethnicity and BMI. Significance of mediation was tested by computing bias-corrected bootstrap CIs with 5000 repetitions. RESULTS: A total of 353 individuals were studied. Plasma glucose, HDL-cholesterol and triacylglycerol mediated 6.8%, 17.9% and 24.3%, respectively, of the association between liver fat and IPFD. Total cholesterol, LDL-cholesterol, alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, γ-glutamyl transpeptidase, insulin, glucagon, amylin, C-peptide, HbA1c, glucagon-like peptide-1 and gastric inhibitory peptide did not mediate the association between liver fat and IPFD. CONCLUSIONS/INTERPRETATION: At least one-quarter of the association between liver fat and IPFD is mediated by specific blood biomarkers (triacylglycerol, HDL-cholesterol and glucose), after accounting for potential confounding by age, sex, ethnicity and BMI. This unveils the complexity of the association between the two fat depots and presents specific targets for intervention.

Association between Intrapancreatic Fat Deposition and the Leptin/Ghrelin Ratio in the Fasted and Postprandial States.

BACKGROUND: The clinical relevance of excess intrapancreatic fat deposition (IPFD) is increasingly appreciated. Leptin and ghrelin are key players in the regulation of food intake, energy balance, and body fat mass. The aim was to investigate the associations of the leptin/ghrelin ratio and its components with IPFD. METHODS: All participants underwent magnetic resonance imaging on a 3T scanner to quantify IPFD. Both fasting and postprandial blood samples were analyzed for leptin and acylated ghrelin. Linear regression analysis was conducted, accounting for visceral/subcutaneous fat volume ratio, glycated hemoglobin, and other covariates. RESULTS: A total of 94 participants (32 women) with a median age of 56 (interquartile range 44-66) years were studied. Their median IPFD was 9.6% (interquartile range 8.8-10.4%). In the fasted state, the leptin/ghrelin ratio (ß = 0.354; 95% confidence interval 0.044-0.663; p = 0.025, in the most adjusted model) and leptin (ß = 0.040; 95% confidence interval 1.003-1.078; p = 0.035, in the most adjusted model) were significantly associated with IPFD. Ghrelin in the fasted state was not significantly associated with IPFD. In the postprandial state, the leptin/ghrelin ratio, leptin, and ghrelin were not significantly associated with IPFD. CONCLUSION: Fasting circulating levels of leptin are directly associated with IPFD. Purposely designed mechanistic studies are warranted to determine how high leptin may contribute to excess IPFD.

Fibrosis reduces severity of acute-on-chronic pancreatitis in humans.

BACKGROUND & AIMS: Acute pancreatitis (AP) and chronic pancreatitis (CP) share etiologies, but AP can be more severe and is associated with a higher rate of mortality. We investigated features of CP that protect against severe disease. The amount of intrapancreatic fat (IPF) is increased in obese patients and fibrosis is increased in patients with CP, so we studied whether fibrosis or fat regulate severity of AP attacks in patients with CP. METHODS: We reviewed records from the University of Pittsburgh Medical Center/Presbyterian Hospital Autopsy Database (1998-2008) for patients with a diagnosis of AP (n = 23), CP (n = 35), or both (AP-on-CP; n = 15). Pancreatic histology samples from these patients and 50 randomly selected controls (no pancreatic disease) were analyzed, and IPF data were correlated with computed tomography data. An adipocyte and acinar cell Transwell coculture system, with or without collagen type I, was used to study the effects of fibrosis on acinar-adipocyte interactions. We studied the effects of nonesterified fatty acids (NEFAs) and adipokines on acinar cells in culture. RESULTS: Levels of IPF were significantly higher in nonobese patients with CP than in nonobese controls. In patients with CP or AP-on-CP, areas of IPF were surrounded by significantly more fibrosis than in controls or patients with AP. Fat necrosis-associated peri-fat acinar necrosis (PFAN, indicated by NEFA spillage) contributed to most of the necrosis observed in samples from patients with AP; however, findings of peri-fat acinar necrosis and total necrosis were significantly lower in samples from patients with CP or AP-on-CP. Fibrosis appeared to wall off the fat necrosis and limit peri-fat acinar necrosis, reducing acinar necrosis. In vitro, collagen I limited the lipolytic flux between acinar cells and adipocytes and prevented increases in adipokines in the acinar compartment. This was associated with reduced acinar cell necrosis. However, NEFAs, but not adipokines, caused acinar cell necrosis. CONCLUSIONS: Based on analysis of pancreatic samples from patients with CP, AP, or AP-on-CP and in vitro studies, fibrosis reduces the severity of acute exacerbations of CP by reducing lipolytic flux between adipocytes and acinar cells.

Correlation between type 2 diabetes mellitus remission and intrapancreatic fat deposition.

BACKGROUND: Intrapancreatic fat deposition (IPFD) exerts a significant negative impact on patients with type 2 diabetes mellitus (T2DM), accelerates disease deterioration, and may lead to impaired ß-cell quality and function. AIM: To investigate the correlation between T2DM remission and IPFD. METHODS: We enrolled 80 abdominally obese patients with T2DM admitted to our institution from January 2019 to October 2023, including 40 patients with weight loss-induced T2DM remission (research group) and 40 patients with short-term intensive insulin therapy-induced T2DM remission (control group). We comparatively analyzed improvements in IPFD [differential computed tomography (CT) values of the spleen and pancreas and average CT value of the pancreas]; levels of fasting blood glucose (FBG), 2-h postprandial blood glucose (2hPBG), and insulin; and homeostasis model assessment of insulin resistance (HOMA-IR) scores. Correlation analysis was performed to explore the association between T2DM remission and IPFD. RESULTS: After treatment, the differential CT values of the spleen and pancreas, FBG, 2hPBG, and HOMA-IR in the research group were significantly lower than those before treatment and in the control group, and the average CT value of the pancreas and insulin levels were significantly higher. Correlation analysis revealed that the greater the T2DM remission, the lower the amount of IPFD. CONCLUSION: T2DM remission and IPFD are inversely correlated.

Intrapancreatic fat deposition and nutritional treatment: the role of various dietary approaches.

Ectopic fat accumulation in various organs and tissues, such as the liver, muscle, kidney, heart, and pancreas, is related to impaired capacity of adipose tissue to accumulate triglycerides, as a consequence of overnutrition and an unhealthy lifestyle. Ectopic fat promotes organ dysfunction and is a key factor in the development and progression of cardiometabolic diseases. Interest in intrapancreatic fat deposition (IPFD) has developed in the last few years, particularly in relation to improvement in methodological techniques for detection of fat in the pancreas, and to growing evidence for the role that IPFD might have in glucose metabolism disorders and cardiometabolic disease. Body weight reduction represents the main option for reducing fat, and the evidence consistently shows that hypocaloric diets are effective in reducing IPFD. Changes in diet composition, independently of changes in energy intake, might offer a more feasible and safe alternative treatment to energy restriction. This current narrative review focused particularly on the possible beneficial role of the diet and its nutrient content, in hypocaloric and isocaloric conditions, in reducing IPFD in individuals with high cardiometabolic risk, highlighting the possible effects of differences in calorie quantity and calorie quality. This review also describes plausible mechanisms by which the various dietary approaches could modulate IPFD.

Obesity and Pancreatic Cancer: Insight into Mechanisms.

The prevalence of obesity in adults and children has dramatically increased over the past decades. Obesity has been declared a chronic progressive disease and is a risk factor for a number of metabolic, inflammatory, and neoplastic diseases. There is clear epidemiologic and preclinical evidence that obesity is a risk factor for pancreatic cancer. Among various potential mechanisms linking obesity with pancreatic cancer, the adipose tissue and obesity-associated adipose tissue inflammation play a central role. The current review discusses selected topics and mechanisms that attracted recent interest and that may underlie the promoting effects of obesity in pancreatic cancer. These topics include the impact of obesity on KRAS activity, the role of visceral adipose tissue, intrapancreatic fat, adipose tissue inflammation, and adipokines on pancreatic cancer development. Current research on lipocalin-2, fibroblast growth factor 21, and Wnt5a is discussed. Furthermore, the significance of obesity-associated insulin resistance with hyperinsulinemia and obesity-induced gut dysbiosis with metabolic endotoxemia is reviewed. Given the central role that is occupied by the adipose tissue in obesity-promoted pancreatic cancer development, preventive and interceptive strategies should be aimed at attenuating obesity-associated adipose tissue inflammation and/or at targeting specific molecules that mechanistically link adipose tissue with pancreatic cancer in obese patients.

Effect of intrapancreatic fat on diabetes outcomes after total pancreatectomy with islet autotransplantation.

BACKGROUND: Pancreatic fat may adversely affect ß-cell mass and function, possibly via local release of non-esterified fatty acids, and proinflammatory and vasoactive factors released by adipose tissue. However, the effects of intrapancreatic fat in patients with chronic pancreatitis undergoing total pancreatectomy with islet autotransplantation (TPIAT) have not been studied. This study investigated whether pancreatic fatty infiltration has a negative effect on metabolic outcomes following TPIAT. METHODS: The association between pancreatic fatty infiltration and diabetes outcomes was studied in 79 patients with low or high pancreatic fat content (LPF [n = 53] and HPF [n = 26], respectively) undergoing TPIAT. Pancreatic fatty infiltration was stratified using gross examinations during isolation and validated with histomorphometry of archived histology samples. RESULTS: Fat area percentage in histology samples differed significantly between the LPF and HPF groups (2.1% ± 4.3% vs 10.6% ± 8.9%, respectively; P = 0.0009). Insulin dependence was more common in the HPF group, whereas more patients in the LPF group were insulin independent or on partial insulin supplementation at 1 year (P = 0.022). Furthermore, 1- and 2-h glucose concentrations during mixed-meal tolerance tests were significantly higher in the HPF group (P = 0.032 and 0.027, respectively) and ß-scores (a composite measure of islet function and metabolic control) were significantly greater in the LPF than HPF group (6.1 ± 1.7 vs 4.6 ± 2.0; P = 0.034). CONCLUSIONS: Patients with HPF were more likely to be insulin dependent, with higher postprandial glucose excursion, suggesting that intrapancreatic fat may lead to ß-cell dysfunction with detrimental effects on diabetes outcomes after TPIAT.