Fat Distribution Within the Pancreas According to Diabetes Status and Insulin Traits

Intra-pancreatic fat is associated with continuous glucose monitoring metrics

AIM

To investigate the relationship of fat in the pancreas with time spent in different glycaemic ranges.

METHODS

Abdominal magnetic resonance imaging at 3.0 Tesla was used to quantify fat in the pancreas as both continuous [i.e. intra-pancreatic fat deposition (IPFD)] and binary (i.e. fatty change of the pancreas vs. normal pancreas) variables. Dexcom G6 devices were used to collect continuous glucose monitoring data every 5 min over a continuous 7-day period. Time above range (TAR), time in range (TIR) and time below range were computed. Statistical models were built to adjust for age, sex, body composition, and other covariates in linear regression analysis and analysis of covariance.

RESULTS

In total, 38 individuals were studied. IPFD was significantly associated with TAR (p = .036) and TIR (p = .042) after adjustment for covariates. For every 1% increase in IPFD, there was a 0.3 unit increase in TAR and a decrease in TIR. Individuals with fatty change of the pancreas, when compared with those with normal pancreas, had significantly higher TAR (p = .034) and lower TIR (p = .047) after adjustment for covariates. Neither IPFD (p = .805) nor fatty change of the pancreas (p = .555) was associated with time below range after adjustment for covariates.

CONCLUSION

Increased fat in the pancreas is associated with excessive glycaemic variability. Fatty change of the pancreas may contribute to heightening the risk of cardiovascular diseases.

Associations of Intrapancreatic Fat Deposition With Incident Diseases of the Exocrine and Endocrine Pancreas: A UK Biobank Prospective Cohort Study

INTRODUCTION

To investigate whether increased intrapancreatic fat deposition (IPFD) heightens the risk of diseases of the exocrine and endocrine pancreas.

METHODS

A prospective cohort study was conducted using data from the UK Biobank. IPFD was quantified using MRI and a deep learning-based framework called nnUNet. The prevalence of fatty change of the pancreas (FP) was determined using sex- and age-specific thresholds. Associations between IPFD and pancreatic diseases were assessed with multivariate Cox-proportional hazard model adjusted for age, sex, ethnicity, body mass index, smoking and drinking status, central obesity, hypertension, dyslipidemia, liver fat content, and spleen fat content.

RESULTS

Of the 42,599 participants included in the analysis, the prevalence of FP was 17.86%. Elevated IPFD levels were associated with an increased risk of acute pancreatitis (hazard ratio [HR] per 1 quintile change 1.513, 95% confidence interval [CI] 1.179-1.941), pancreatic cancer (HR per 1 quintile change 1.365, 95% CI 1.058-1.762) and diabetes mellitus (HR per 1 quintile change 1.221, 95% CI 1.132-1.318). FP was also associated with a higher risk of acute pancreatitis (HR 3.982, 95% CI 2.192-7.234), pancreatic cancer (HR 1.976, 95% CI 1.054-3.704), and diabetes mellitus (HR 1.337, 95% CI 1.122-1.593, P = 0.001).

DISCUSSION

FP is a common pancreatic disorder. Fat in the pancreas is an independent risk factor for diseases of both the exocrine pancreas and endocrine pancreas.

Relationship of Liver Blood Tests and T1 Relaxation Time With Intra-pancreatic Fat Deposition

Background

Liver is well recognised as a metabolically active organ. While intra-pancreatic fat deposition (IPFD) is emerging as an important player in the whole-body metabolism, the interplay between the liver and IPFD has been poorly investigated. This study aimed to investigate the associations of liver blood tests and non-invasive tests for hepatic fibrosis with IPFD.

Methods

Participants underwent a 3.0 Tesla magnetic resonance imaging to measure IPFD and map liver T1 (longitudinal relaxation time). Four liver tests were done on the same sample of blood. Hepatic fibrosis risk score (BARD) was calculated. Linear regression models were built, accounting for age, sex, visceral-to-subcutaneous fat ratio, and other covariates.

Results

A total of 143 individuals were studied. In the most adjusted model, alkaline phosphatase (P < 0.001), alanine aminotransferase (P < 0.001), and γ-glutamyl transferase (P = 0.042) were significantly positively associated with IPFD. The BARD score was not significantly associated with IPFD in the most adjusted model (P = 0.295). T1 relaxation time of the liver was not significantly associated with IPFD in the most adjusted model (P = 0.782).

Conclusions

Elevated alkaline phosphatase, alanine aminotransferase, and γ-glutamyl transferase are associated with increased IPFD. Hepatic fibrosis does not appear to be associated with IPFD.

Predictive value of anthropometric and biochemical indices in non-alcoholic fatty pancreas disease: a cross-sectional study

OBJECTIVES

Triglyceride (TG), triglyceride-glucose index (TyG), body mass index (BMI), TyG-BMI and triglyceride to high-density lipoprotein ratio (TG/HDL) have been reported to be reliable predictors of non-alcoholic fatty liver disease. However, there are few studies on potential predictors of non-alcoholic fatty pancreas disease (NAFPD). Our aim was to evaluate these and other parameters for predicting NAFPD.

DESIGN

Cross-sectional study design.

SETTING

Physical examination centre of a tertiary hospital in China.

PARTICIPANTS

This study involved 1774 subjects who underwent physical examinations from January 2016 to September 2016.

PRIMARY AND SECONDARY OUTCOME MEASURES

From each subject, data were collected for 13 basic physical examination and blood biochemical parameters: age, weight, height, BMI, TyG, TyG-BMI, high-density lipoprotein (HDL), low-density lipoprotein, total cholesterol, TG, fasting plasma glucose, TG/HDL and uric acid. NAFPD was diagnosed by abdominal ultrasonography. A logistic regression model with a restricted cubic spline was used to evaluate the relationship between each parameter and NAFPD. The receiver operating characteristic (ROC) curve was used to calculate the area under the curve for each parameter.

RESULTS

HDL was negatively correlated with NAFPD, height was almost uncorrelated with NAFPD and the remaining 11 parameters were positively correlated with NAFPD. ROC curve showed that weight-related parameters (weight, BMI and TyG-BMI) and TG-related parameters (TyG, TG and TG/HDL) had high predictive values for the identification of NAFPD. The combinations of multiple parameters had a better prediction effect than a single parameter. All the predictive effects did not differ by sex.

CONCLUSIONS

Weight-related and TG-related parameters are good predictors of NAFPD in all populations. BMI showed the greatest predictive potential. Multiparameter combinations appear to be a good way to predict NAFPD.

Associations of pancreas fat content and size with markers of iron metabolism

OBJECTIVE

To comprehensively investigate the associations of pancreas fat content and size with circulating markers of iron metabolism.

METHODS

A total of 116 individuals underwent magnetic resonance imaging and spectroscopy on a 3.0 Tesla scanner, exclusively for the purpose of the COSMOS research programme. Intra-pancreatic fat deposition, total pancreas volume, liver fat content, visceral and subcutaneous fat volumes were quantified. Plasma levels of hepcidin and ferritin were measured. Multiple linear regression analysis was conducted, adjusting for body mass index, age, and sex.

RESULTS

Total intra-pancreatic fat deposition was inversely associated with hepcidin (β = -0.54, 95 % confidence interval -1.02 to -0.07) whereas total pancreas volume was not associated with hepcidin (β = 0.36, 95 % confidence interval -7.12 to 7.84) in the most adjusted model. Neither total intra-pancreatic fat deposition (β = -0.03, 95 % confidence interval -0.39 to 0.33) nor total pancreas volume (β = -1.02, 95 % confidence interval -6.67 to 4.63) was associated with ferritin in the most adjusted model. Subcutaneous fat, visceral fat, and liver fat were not associated with hepcidin. Subcutaneous fat was inversely associated with ferritin (β = -0.06, 95 % CI -0.11 to -0.01) whereas visceral fat (β = 0.05, 95 % CI -0.01 to 0.14) and liver fat (β = 0.09, 95 % CI -0.04 to 0.34) were not associated with ferritin in the most adjusted model.

CONCLUSIONS

Increased intra-pancreatic fat deposition, but not other fat depots, is associated with reduced circulating levels of hepcidin. Deranged iron metabolism may play a role in the pathogenesis of fatty change of the pancreas.

Metabolic Sequelae: The Pancreatitis Zeitgeist of the 21st Century

Holistic management of pancreatitis means that gastroenterologists in the 21st Century should think beyond improving in-hospital outcomes of pancreatitis alone. In particular, there is considerable room for optimizing the management of new-onset diabetes, exocrine pancreatic insufficiency, and other metabolic sequelae of pancreatitis. The present article provides state-of-the-art information on classification, terminology, and burden of the common sequelae of pancreatitis. A high-risk group of patients with pancreatitis is identified, which is positioned to benefit the most from the metabolic sequelae surveillance program introduced in this article. The program involves continuous follow-up after pancreatitis diagnosis, with the focus on early identification of new-onset diabetes after pancreatitis and exocrine pancreatic insufficiency. The metabolic sequelae surveillance program is scalable and has the potential to reduce the burden of pancreatitis through tertiary prevention in the decades to come.

Remnant cholesterol, but not low-density lipoprotein cholesterol, is associated with intra-pancreatic fat deposition

AIM

To investigate the associations of components of the lipid panel (and its derivatives) with intra-pancreatic fat deposition (IPFD).

METHODS

All participants underwent abdominal magnetic resonance imaging on the same 3.0-Tesla scanner and IPFD was quantified. Blood samples were collected in the fasted state for analysis of lipid panel components. A series of linear regression analyses was conducted, adjusting for age, sex, ethnicity, body mass index, fasting plasma glucose, homeostatic model assessment of insulin resistance, and liver fat deposition.

RESULTS

A total of 348 participants were included. Remnant cholesterol (P = 0.010) and triglyceride levels (P = 0.008) were positively, and high-density lipoprotein cholesterol level (P = 0.001) was negatively, associated with total IPFD in the most adjusted model. Low-density lipoprotein cholesterol and total cholesterol were not significantly associated with total IPFD. Of the lipid panel components investigated, remnant cholesterol explained the greatest proportion (9.9%) of the variance in total IPFD.

CONCLUSION

Components of the lipid panel have different associations with IPFD. This may open up new opportunities for improving outcomes in people at high risk for cardiovascular diseases (who have normal low-density lipoprotein cholesterol) by reducing IPFD.

Comprehensive analysis of dyslipidemia states associated with fat in the pancreas

BACKGROUND

The global burden of cardiovascular diseases continues to rise, and it is increasingly acknowledged that guidelines based on traditional risk factors fail to identify a substantial fraction of people who develop cardiovascular diseases. Fat in the pancreas could be one of the unappreciated risk factors. This study aimed to investigate the associations of dyslipidemia states with fat in the pancreas.

METHODS

All participants underwent magnetic resonance imaging on the same 3.0 T scanner for quantification of fat in the pancreas, analyzed as both binary (i.e., fatty change of the pancreas) and continuous (i.e., intra-pancreatic fat deposition) variables. Statistical analyses were adjusted for body mass index, glycated hemoglobin, fasting insulin, ethnicity, age, and sex.

RESULTS

There were 346 participants studied. On most adjusted analyses, high-density lipoprotein cholesterol dyslipidemia was significantly associated with both fatty change of the pancreas (p = 0.010) and intra-pancreatic fat deposition (p = 0.008). Neither low-density lipoprotein cholesterol dyslipidemia nor triglyceride dyslipidemia were significantly associated with fatty change of the pancreas and intra-pancreatic fat deposition. The absence of any dyslipidemia was inversely associated with both fatty change of the pancreas (p = 0.016) and intra-pancreatic fat deposition (p < 0.001).

CONCLUSIONS

Dyslipidemias are uncoupled when it comes to the relationship with fat in the pancreas, with only high-density lipoprotein cholesterol dyslipidemia having a consistent and strong link with it. The residual cardiovascular diseases risk may be attributed to fatty change of the pancreas.

Relationship of Iron Intake, Ferritin, and Hepcidin with the Transverse Relaxation Rate of Water Protons in the Pancreas

(1) Background: There is a paucity of markers of iron metabolism in health and disease. The aim was to investigate the associations of iron metabolism with pancreas transverse water proton relaxation rate (R2water) in healthy individuals and people after an attack of pancreatitis. (2) Methods: All participants underwent a 3.0 T magnetic resonance imaging of the abdomen on the same scanner. High-speed T2-corrected multi-echo (HISTO) acquisition at single-voxel magnetic resonance spectroscopy and inline processing were used to quantify pancreas R2water. Habitual dietary intake of iron was determined using the EPIC-Norfolk food frequency questionnaire. Circulating levels of ferritin and hepcidin were measured. Generalised additive models were used, adjusting for age, sex, body mass index, and haemoglobin A1c. (3) Results: A total of 139 individuals (47 healthy individuals, 54 individuals after acute pancreatitis, and 38 individuals after chronic pancreatitis) were included. Total dietary intake of iron was significantly associated with pancreas R2water, consistently in healthy individuals (p < 0.001), individuals after acute pancreatitis (p < 0.001), and individuals after chronic pancreatitis (p < 0.001) across all the statistical models. Ferritin was significantly associated with pancreas R2water, consistently in healthy individuals (p < 0.001), individuals after acute pancreatitis (p < 0.001), and individuals after chronic pancreatitis (p = 0.01) across all adjusted models. Hepcidin was significantly associated with pancreas R2water in individuals after acute pancreatitis (p < 0.001) and individuals after chronic pancreatitis (p = 0.04) in the most adjusted model. (4) Conclusions: Pancreas R2water, corrected for T2, is related to iron metabolism in both health and pancreatitis. This non-invasive marker could be used for automated in vivo identification of intra-pancreatic iron deposition.

Relationship of Serum Bile Acids with Fat Deposition in the Pancreas, Liver, and Skeletal Muscle

Introduction

Ectopic fat deposition is well appreciated as a key contributor to digestive and liver diseases. Bile acids have emerged as pleiotropic signalling molecules involved in numerous metabolic pathways. The aim was to study the associations of bile acids with ectopic fat deposition and lipid panel.

Methods

A single 3.0 Tesla magnetic resonance imaging scanner was employed to measure fat deposition in the pancreas, liver, and skeletal muscle in 76 adults. Blood samples were drawn to determine total bile acids and lipid panel. Linear regression analyses were run, taking into account age, sex, body mass index, and other covariates.

Results

The studied ectopic fat depots were not significantly associated with levels of total bile acids in serum. Total bile acids were significantly associated high-density lipoprotein cholesterol - consistently in both the unadjusted (p = 0.018) and all adjusted models (p = 0.012 in the most adjusted model). Low-density lipoprotein cholesterol, total cholesterol, and triglycerides were not significantly associated with total bile acids in both the unadjusted and all adjusted models.

Conclusion

Fat deposition in the pancreas, liver, and skeletal muscle is not associated with circulating levels of total bile acids. High-density lipoprotein cholesterol is the only component of lipid panel that is associated with total bile acids.

Intra-pancreatic fat deposition across the pancreatitis spectrum and the influence of gut hormones

BACKGROUND AND AIMS

Acute pancreatitis (AP) and chronic pancreatitis (CP) often represent parts of the spectrum of disease. While growing evidence indicates that intra-pancreatic fat deposition (IPFD) plays an important role in the pathogenesis of pancreatitis, no study of living individuals has investigated IPFD in both AP and CP. Further, the associations between IPFD and gut hormones remain to be elucidated. The aims were to investigate the associations of IPFD with AP, CP, and health; and to study whether gut hormones affect these associations.

METHODS

Magnetic resonance imaging on the same 3.0 Tesla scanner was used to determine IPFD in 201 study participants. These participants were arranged into the health, AP, and CP groups. Gut hormones (ghrelin, glucagon-like peptide-1, gastric inhibitory peptide, peptide YY, and oxyntomodulin) were measured in blood, both after an 8-hour overnight fasting and after ingestion of a standardised mixed meal. A series of linear regression analyses was run, accounting for age, sex, ethnicity, body mass index, glycated haemoglobin, and triglycerides.

RESULTS

Both the AP group and CP group had significantly higher IPFD in comparison with the health group, consistently across all models (p for trend 0.027 in the most adjusted model). Ghrelin in the fasted state had a significant positive association with IPFD in the AP group (but not the CP or health group), consistently across all models (p = 0.019 in the most adjusted model). None of the studied gut hormones in the postprandial state was significantly associated with IPFD.

CONCLUSION

Fat deposition in the pancreas is similarly high in individuals with AP and those with CP. The gut-brain axis, and more specifically overexpression of ghrelin, may contribute to increased IPFD in individuals with AP.

Association between Intrapancreatic Fat Deposition and Lower High-Density Lipoprotein Cholesterol in Individuals with Newly Diagnosed T2DM

BACKGROUND

Intrapancreatic fat deposition (IPFD) usually occurs in individuals with type 2 diabetes mellitus (T2DM), but its physiopathological influence remains controversial. The present study aimed to investigate IPFD and its associations with various aspects of glucose and lipid metabolism in individuals with newly diagnosed T2DM.

METHODS

A total of 100 individuals were included, consisting of 80 patients with newly diagnosed T2DM and 20 age- and sex-matched healthy controls. Then, we assessed IPFD using magnetic resonance imaging (MRI) and various parameters of glucose and lipid metabolism.

RESULTS

Individuals with newly diagnosed T2DM had a significantly higher IPFD (median: 12.34%; IQR, 9.19-16.60%) compared with healthy controls (median: 6.35%; IQR, 5.12-8.96%) (p < 0.001). In individuals with newly diagnosed T2DM, IPFD was significantly associated with FINS and HOMA-IR in unadjusted model (β = 0.239, p=0.022; β = 0.578, p=0.007, respectively) and adjusted model for age and sex (β = 0.241, p=0.022; β = 0.535, p=0.014, respectively), but these associations vanished after adjustment for age, sex, and BMI. The OR of lower HDL-C for the prevalence of high IPFD was 4.22 (95% CI, 1.41 to 12.69; p=0.010) after adjustment for age, sex, BMI, and HbA1c.

CONCLUSIONS

Lower HDL-C was an independent predictor for a high degree of IPFD.

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, HbA_1c, 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.