Obesity, metabolic disease and the pancreas-Quantitative imaging of pancreatic fat

Diabetes remission and nonalcoholic fatty pancreas disease

This editorial focuses on the relationship between nonalcoholic fatty pancreas disease (NAFPD) and the development and remission of type 2 diabetes (T2D). NAFPD is characterized by intrapancreatic fatty deposition associated with obesity and not associated with alcohol abuse, viral infections, and other factors. Ectopic fat deposition in the pancreas is associated with the development of T2D, and the underlying mechanism is lipotoxic β-cell dysfunction. However, the results on the relationship between intrapancreatic fat deposition (IPFD) and β-cell function are conflicting. Regardless of the therapeutic approach, weight loss improves IPFD, glycemia, and β-cell function. Pancreatic imaging is valuable for clinically monitoring and evaluating the management of T2D.

Diverse associations between pancreatic intra-, inter-lobular fat and the development of type 2 diabetes in overweight or obese patients

Pancreatic fat is associated with obesity and type 2 diabetes mellitus (T2DM); however, the relationship between different types of pancreatic fat and diabetes status remains unclear. Therefore, we aimed to determine the potential of different types of pancreatic fat accumulation as a risk factor for T2DM in overweight or obese patients. In total, 104 overweight or obese patients were recruited from January 2020 to December 2022. The patients were divided into three groups: normal glucose tolerance (NGT), impaired fasting glucose or glucose tolerance (IFG/IGT), and T2DM. mDixon magnetic resonance imaging (MRI) was used to detect pancreatic fat in all three groups of patients. The pancreatic head fat (PHF), body fat (PBF), and tail fat (PTF) in the IFG/IGT group were 21, 20, and 31% more than those in the NGT group, respectively. PHF, PBF, and PTF were positively associated with glucose metabolic dysfunction markers in the NGT group, and inter-lobular fat volume (IFV) was positively associated with these markers in the IFG/IGT group. The areas under the receiver operating characteristic curves for PHF, PBF, and PTF (used to evaluate their diagnostic potential for glucose metabolic dysfunction) were 0.73, 0.73, and 0.78, respectively, while those for total pancreatic volume (TPV), pancreatic parenchymal volume, IFV, and IFV/TPV were 0.67, 0.67, 0.66, and 0.66, respectively. These results indicate that intra-lobular pancreatic fat, including PHF, PTF, and PBF, may be a potential independent risk factor for the development of T2DM. Additionally, IFV exacerbates glucose metabolic dysfunction. Intra-lobular pancreatic fat indices were better than IFV for the diagnosis of glucose metabolic dysfunction.

Multimodality Imaging in Metabolic Syndrome: State-of-the-Art Review

Metabolic syndrome comprises a set of risk factors that include abdominal obesity, impaired glucose tolerance, hypertriglyceridemia, low high-density lipoprotein levels, and high blood pressure, at least three of which must be fulfilled for diagnosis. Metabolic syndrome has been linked to an increased risk of cardiovascular disease and type 2 diabetes mellitus. Multimodality imaging plays an important role in metabolic syndrome, including diagnosis, risk stratification, and assessment of complications. CT and MRI are the primary tools for quantification of excess fat, including subcutaneous and visceral adipose tissue, as well as fat around organs, which are associated with increased cardiovascular risk. PET has been shown to detect signs of insulin resistance and may detect ectopic sites of brown fat. Cardiovascular disease is an important complication of metabolic syndrome, resulting in subclinical or symptomatic coronary artery disease, alterations in cardiac structure and function with potential progression to heart failure, and systemic vascular disease. CT angiography provides comprehensive evaluation of the coronary and systemic arteries, while cardiac MRI assesses cardiac structure, function, myocardial ischemia, and infarction. Liver damage results from a spectrum of nonalcoholic fatty liver disease ranging from steatosis to fibrosis and possible cirrhosis. US, CT, and MRI are useful in assessing steatosis and can be performed to detect and grade hepatic fibrosis, particularly using elastography techniques. Metabolic syndrome also has deleterious effects on the pancreas, kidney, gastrointestinal tract, and ovaries, including increased risk for several malignancies. Metabolic syndrome is associated with cerebral infarcts, best evaluated with MRI, and has been linked with cognitive decline. ©RSNA, 2024 Test Your Knowledge questions for this article are available in the supplemental material. See the invited commentary by Pickhardt in this issue.

Relationship between Cytokines and Metabolic Syndrome Components: Role of Pancreatic-Derived Factor, Interleukin-37, and Tumor Necrosis Factor-α in Metabolic Syndrome Patients

The metabolic syndrome (MetS) is a serious public health issue that affects people all over the world. Notably, insulin resistance, prothrombotic activity, and inflammatory state are associated with MetS. This study aims to explore the relationship between cytokines and tumor necrosis factor-α (TNF-α), pancreatic-derived factor (PANDER), and interleukin (IL-)-37 and the accumulation of MetS components. Eligible participants were divided into four groups as follows: group 1, patients with dyslipidemia; group 2, patients with dyslipidemia and obesity; group 3, patients with dyslipidemia, obesity, and hypertension; and group 4, patients with dyslipidemia, obesity, hypertension, and hyperglycemia. This study exhibited that serum levels of TNF-α and PANDER were significantly elevated (P < 0.001) in the MetS groups, while IL-37 level and IL-37 mRNA expression were significantly decreased (P < 0.001) relative to healthy controls. Moreover, this study has revealed significant correlations (P < 0.001) between MetS components and TNF-α, PANDER, and IL-37 levels in MetS patients. The aforementioned results suggested the association between the proinflammatory cytokine (TNF-α and PANDER) and anti-inflammatory cytokine (IL-37) with the accumulation of MetS components. Hence, the overall outcome indicated that PANDER and IL-37 may be considered novel biomarkers associated with increased risk of MetS and can be used as a promising therapeutic target in preventing, ameliorating, and treating metabolic disorders.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12291-022-01079-z.

Modeling tissue co-regulation estimates tissue-specific contributions to disease

Integrative analyses of genome-wide association studies and gene expression data have implicated many disease-critical tissues. However, co-regulation of genetic effects on gene expression across tissues impedes distinguishing biologically causal tissues from tagging tissues. In the present study, we introduce tissue co-regulation score regression (TCSC), which disentangles causal tissues from tagging tissues by regressing gene-disease association statistics (from transcriptome-wide association studies) on tissue co-regulation scores, reflecting correlations of predicted gene expression across genes and tissues. We applied TCSC to 78 diseases/traits (average n = 302,000) and gene expression prediction models for 48 GTEx tissues. TCSC identified 21 causal tissue-trait pairs at a 5% false discovery rate (FDR), including well-established findings, biologically plausible new findings (for example, aorta artery and glaucoma) and increased specificity of known tissue-trait associations (for example, subcutaneous adipose, but not visceral adipose, and high-density lipoprotein). TCSC also identified 17 causal tissue-trait covariance pairs at 5% FDR. In conclusion, TCSC is a precise method for distinguishing causal tissues from tagging tissues.

Adipose Tissue Hyperplasia and Hypertrophy in Common and Syndromic Obesity-The Case of BBS Obesity

Obesity is a metabolic state generated by the expansion of adipose tissue. Adipose tissue expansion depends on the interplay between hyperplasia and hypertrophy, and is mainly regulated by a complex interaction between genetics and excess energy intake. However, the genetic regulation of adipose tissue expansion is yet to be fully understood. Obesity can be divided into common multifactorial/polygenic obesity and monogenic obesity, non-syndromic and syndromic. Several genes related to obesity were found through studies of monogenic non-syndromic obesity models. However, syndromic obesity, characterized by additional features other than obesity, suggesting a more global role of the mutant genes related to the syndrome and, thus, an additional peripheral influence on the development of obesity, were hardly studied to date in this regard. This review summarizes present knowledge regarding the hyperplasia and hypertrophy of adipocytes in common obesity. Additionally, we highlight the scarce research on syndromic obesity as a model for studying adipocyte hyperplasia and hypertrophy, focusing on Bardet-Biedl syndrome (BBS). BBS obesity involves central and peripheral mechanisms, with molecular and mechanistic alternation in adipocyte hyperplasia and hypertrophy. Thus, we argue that using syndromic obesity models, such as BBS, can further advance our knowledge regarding peripheral adipocyte regulation in obesity.

Causal relationships between obesity and pancreatobiliary diseases: a two-sample Mendelian randomization study

Previous observational studies have investigated the relationship between obesity and the biliary tract and pancreas. The causality, however, is still to be confirmed. This study was designed to explore the causality between obesity which included body mass index(BMI), circumference (WC), hip circumference (HC) and waist-to-hip ratio (WHR), and pancreatobiliary diseases with a Two-Sample Mendelian Randomization(MR) analysis. single-nucleotide polymorphisms used in our study were derived from genome-wide association studies (GWAS). The inverse variance weighted was the dominated method to evaluate the causality. The heterogeneity was validated by Cochran's Q test. The pleiotropy was validated by MR-Egger regression and MR-PRESSO. The stability and reliability of the results were illustrated by the 'leave-one-out'sensitivity analysis. The MR results explored positive causal effects of BMI (OR: 1.021; 95% CI: from 1.016 to 1.027; P = 4.25 × 10^-15) and WC (OR: 1.021; 95% CI: from 1.015 to 1.028; P = 1.65 × 10^-10) on pancreatobiliary diseases. However, no causality existed between HC, WHR and pancreatobiliary diseases. This study reminded that general obesity and abdominal obesity required weight loss to prevent pancreatic biliary disease.

Automated whole-volume measurement of CT fat fraction of the pancreas: correlation with Dixon MR imaging

OBJECTIVES

This study aimed to assess the feasibility of pancreatic steatosis quantification by automated whole-volume measurement of the fat fraction of the pancreas on CT in comparison to MRI using proton-density fat fraction (PDFF) techniques.

METHODS

Fifty-nine patients who underwent both CT and MRI were analyzed. Automated whole-volume measurement of pancreatic fat on unenhanced CT was performed by a histogram analysis with local thresholding. Three sets of CT fat volume fraction (FVF) (%) values with thresholds of -30 Hounsfield unit (HU), -20 HU and -10 HU were compared to MR-FVF (%) values measured on a PDFF map.

RESULTS

The median -30 HU CT-FVF, -20 HU CT-FVF, -10 HU CT-FVF and MR-FVF values of the pancreas were 8.6% (interquartile range (IQR), 11.3), 10.5% (IQR, 13.2), 13.4% (IQR, 16.1) and 10.9% (IQR, 9.7), respectively. The -30 HU CT-FVF (%), -20 HU CT-FVF (%) and -10 HU CT-FVF (%) of the pancreas showed a significant positive correlation with the MR-FVF (%) of the pancreas (ρ = 0.898, p < 0.001, ρ = 0.905, p < 0.001, ρ = 0.909, p < 0.001, respectively). The -20 HU CT-FVF (%) displayed reasonable agreement with the MR-FVF (%) with a low absolute fixed bias (mean difference, 0.32%; limit of agreement from -10.1 to 10.7%).

CONCLUSION

The automated whole-volume measurement of the CT fat fraction of the pancreas using the threshold CT attenuation value of -20 HU may be a feasible, non-invasive, and convenient technique for quantifying pancreatic steatosis.

ADVANCES IN KNOWLEDGE

CT-FVF value of the pancreas had a positive correlation with the MR-FVF value. The -20 HU CT-FVF may be a convenient technique for quantifying pancreatic steatosis.

Changes in pancreatic exocrine function, fat and fibrosis in diabetes mellitus: analysis using MR imaging

OBJECTIVE

To evaluate the relationships between hemoglobin A1c (HbA1c) levels with exocrine pancreatic function using cine-dynamic magnetic resonance cholangiopancreatography (MRCP) and the pancreatic parenchyma using fat-suppressed T1 mapping and the proton density fat fraction (PDFF).

METHODS

Patients who underwent 3T-MRI and HbA1c measurement were retrospectively recruited. MRI included cine-dynamic MRCP with a spatially selective inversion-recovery (SS-IR) pulse, fat-suppressed Look-Locker T1 mapping and multiecho 3D Dixon-based PDFF mapping. The pancreatic exocrine secretion grade on cine-dynamic MRCP, T1 values, and PDFF were analyzed in non-diabetic (n = 32), pre-diabetic (n = 44) and diabetic (n = 23) groups defined using HbA1c.

RESULTS

PDFF was weakly correlation with HbA1c (ρ = 0.30, p = 0.002). No correlations were detected between HbA1c and secretion grade (ρ = - 0.16, p = 0.118) or pancreatic parenchymal T1 (ρ = 0.13, p = 0.19). The secretion grade was comparable between the three groups. The T1 value was higher in diabetic (T1 = 1006.2+/- 224.8 ms) than in non-diabetic (T1 = 896.2+/- 86.3 ms, p = 0.010) and pre-diabetic (T1 = 870.1+/- 91.7 ms, p < 0.010) patients. The PDFF was higher in diabetic (FF = 11.8+/- 8.7 %) than in non-diabetic (FF = 6.8+/- 4.2 %, p = 0.014) patients.

CONCLUSION

Pancreatic exocrine function, T1, and FF showed no correlation with HbA1c. Pancreatic T1 and fat fraction is increased in patients with Type 2 diabetes mellitus.

ADVANCES IN KNOWLEDGE

This study demonstrates unaffected exocrine function in pre-diabetes and diabetes and confirms that pancreatic parenchymal T1 and FF are increased in patients with diabetes.

Pancreatic changes with lifestyle and age: What is normal and what is concerning?

During the aging process, typical morphological changes occur in the pancreas, which leads to a specific "patchy lobular fibrosis in the elderly." The aging process in the pancreas is associated with changes in volume, dimensions, contour, and increasing intrapancreatic fat deposition. Typical changes are seen in ultrasonography, computed tomography, endosonography, and magnetic resonance imaging. Typical age-related changes must be distinguished from lifestyle-related changes. Obesity, high body mass index, and metabolic syndrome also lead to fatty infiltration of the pancreas. In the present article, age-related changes in morphology and imaging are discussed. Particular attention is given to the sonographic verification of fatty infiltration of the pancreas. Ultrasonography is a widely used screening examination method. It is important to acknowledge the features of the normal aging processes and not to interpret them as pathological findings. Reference is made to the uneven fatty infiltration of the pancreas. The differential diagnostic and the differentiation from other processes and diseases leading to fatty infiltration of the pancreas are discussed.

Liver fat is superior to visceral and pancreatic fat as a risk biomarker of impaired glucose regulation in overweight/obese subjects

AIM

To investigate the distribution of abdominal fat, particularly ectopic fat accumulation, in relation to glucose metabolism in overweight/obese patients.

MATERIALS AND METHODS

This study included 257 overweight/obese subjects with body mass index ≥23 kg/m² . All the subjects underwent an oral glucose tolerance test. Magnetic resonance imaging-proton density fat fraction was used to measure fat accumulation in the liver, pancreas and abdomen. Impaired glucose regulation (IGR) was defined as the presence of prediabetes or diabetes.

RESULTS

Liver fat content (LFC) and visceral adipose tissue (VAT) were higher in overweight/obese subjects with diabetes than in those with normal glucose tolerance (NGT). No significant differences were observed in the pancreas fat content and subcutaneous fat area between subjects with NGT and IGR. LFC was an independent risk factor of IGR (odds ratio = 1.824 per standard deviation unit, 95% CI 1.242-2.679, p = .002). Compared with the lowest tertile of LFC, the multivariate-adjusted odds ratio for the prevalence of IGR in the highest tertile was 2.842 (95% CI 1.205-6.704). However, no association was observed between the VAT per standard deviation increment and tertiles after adjusting for multiple factors. For discordant visceral and liver fat phenotypes, the high LFC-low VAT and high LFC-high VAT groups had a higher prevalence of IGR than the low LFC-low VAT group. However, there was no difference in the prevalence of IGR between the low LFC-low VAT and low LFC-high VAT groups.

CONCLUSION

Compared with visceral and pancreatic fat content, LFC is a superior risk biomarker for IGR in overweight/obese subjects.

Using Free-Breathing MRI to Quantify Pancreatic Fat and Investigate Spatial Heterogeneity in Children

BACKGROUND

MRI acquisition for pediatric pancreatic fat quantification is limited by breath-holds (BH). Full segmentation (FS) or small region of interest (ROI) analysis methods may not account for pancreatic fat spatial heterogeneity, which may limit accuracy.

PURPOSE

To improve MRI acquisition and analysis for quantifying pancreatic proton-density fat fraction (pPDFF) in children by investigating free-breathing (FB)-MRI, characterizing pPDFF spatial heterogeneity, and relating pPDFF to clinical markers.

STUDY TYPE

Prospective.

POPULATION

A total of 34 children, including healthy (N = 16, 8 female) and overweight (N = 18, 5 female) subjects.

FIELD STRENGTH AND SEQUENCES

3 T; multiecho gradient-echo three-dimensional (3D) stack-of-stars FB-MRI, multiecho gradient-echo 3D Cartesian BH-MRI.

ASSESSMENT

A radiologist measured FS- and ROI-based pPDFF on FB-MRI and BH-MRI PDFF maps, with anatomical images as references. Regional pPDFF in the pancreatic head, body, and tail were measured on FB-MRI. FS-pPDFF, ROI-pPDFF, and regional pPDFF were compared, and related to clinical markers, including hemoglobin A1c.

STATISTICAL TESTS

T-test, Bland-Altman analysis, Lin's concordance correlation coefficient (CCC), one-way analysis of variance, and Spearman's rank correlation coefficient were used. P < 0.05 was considered significant.

RESULTS

FS-pPDFF and ROI-pPDFF from FB-MRI and BH-MRI had mean difference = 0.4%; CCC was 0.95 for FS-pPDFF and 0.62 for ROI-pPDFF. FS-pPDFF was higher than ROI-pPDFF (10.4% ± 6.4% vs. 4.2% ± 2.8%). Tail-pPDFF (11.6% ± 8.1%) was higher than body-pPDFF (8.9% ± 6.3%) and head-pPDFF (8.7% ± 5.2%). Head-pPDFF and body-pPDFF positively correlated with hemoglobin A1c.

DATA CONCLUSION

FB-MRI pPDFF is comparable to BH-MRI. Spatial heterogeneity affects pPDFF quantification. Regional measurements of pPDFF in the head and body were correlated with hemoglobin A1c, a marker of insulin sensitivity.

EVIDENCE LEVEL

2 TECHNICAL EFFICACY: Stage 2.

Pancreatic fat fraction in dual-energy computed tomography as a potential quantitative parameter in the detection of type 2 diabetes mellitus

PURPOSE

To investigate the clinical value of measuring pancreatic fat fraction using dual-energy computed tomography (DECT) in association with type 2 diabetes mellitus (T2DM).

MATERIALS AND METHODS

This retrospective study included patients who underwent abdominal DECT between September 2021 and July 2022. The fat fractions in the head, body, and tail of the pancreas were calculated using fat maps generated from unenhanced DECT images, and CT values were measured at the same locations. The intraclass correlation coefficient (ICC) was used to analyze the reproducibility of measurements from two observers. Diagnostic performance was assessed using receiver operating characteristic curves.

RESULTS

Seventy-eight patients, including 45 T2DM patients and 33 controls, were enrolled. The fat fractions of the pancreas were significantly higher in the T2DM group than in the control group (pancreatic head: 8.4 ± 6.3 % vs 5.1 ± 3.9 %; pancreatic body: 4.8 ± 4.0 % vs 2.7 ± 3.9 %; and pancreatic tail: 5.3 ± 3.2 % vs 2.7 ± 2.9 %, all p < 0.05). And the CT values of the pancreas were significantly lower in the T2DM group than in the control group (pancreatic head: 41.1 ± 8.5 HU vs 45.7 ± 4.6 HU; pancreatic body: 44.4 ± 5.0 HU vs 47.4 ± 3.7 HU; and pancreatic tail: 44.5 ± 5.0 HU vs 47.6 ± 3.2 HU, all p < 0.05). The fat fraction of the pancreatic tail was the best indicator for distinguishing T2DM patients from the controls (area under the curve: 0.716 (95 % CI: 0.601, 0.832), sensitivity: 64.4 % (95 % CI: 48.7 %, 77.7 %), and specificity: 78.8 % (95 % CI: 60.6 %, 90.4 %)).

CONCLUSION

The DECT fat fractions of the pancreas could be a valuable additional parameter in the detection of T2DM.

GLP-1R Signaling and Functional Molecules in Incretin Therapy

Glucagon-like peptide-1 receptor (GLP-1R) is a critical therapeutic target for type 2 diabetes mellitus (T2DM). The GLP-1R cellular signaling mechanism relevant to insulin secretion and blood glucose regulation has been extensively studied. Numerous drugs targeting GLP-1R have entered clinical treatment. However, novel functional molecules with reduced side effects and enhanced therapeutic efficacy are still in high demand. In this review, we summarize the basis of GLP-1R cellular signaling, and how it is involved in the treatment of T2DM. We review the functional molecules of incretin therapy in various stages of clinical trials. We also outline the current strategies and emerging techniques that are furthering the development of novel therapeutic drugs for T2DM and other metabolic diseases.

Visual assessment of pancreatic fat deposition: useful grading system and the relation to BMI and diabetes

PURPOSE

To establish a simple and clinically useful method for the visual assessment of pancreatic fat deposition using computed tomography (CT) images, and to evaluate the relationship of the pancreatic fat deposition with body mass index (BMI) and type 2 diabetes mellitus (DM).

MATERIALS AND METHODS

We used a four-scale grading system as the visual assessment criteria for pancreatic fat deposition using CT images. Pancreatic fat deposition was assessed for 200 patients and the results were compared with the CT attenuation-based assessment. In addition, the relationships of pancreatic fat deposition with BMI and type 2 DM were investigated.

RESULTS

The visual and CT attenuation-based assessments were considered consistent. The results of the visual assessment suggested that mild and moderate pancreatic fat deposition correlated with BMI and presence of type 2 DM while severe fat deposition did not correlate with them. No correlation between pancreatic fat deposition and HbA1c level was found.

CONCLUSION

The visual assessment criteria we used were consistent with CT attenuation-based assessment and may be useful for clinical application of pancreatic fat deposition. According to the visually assessment, mild or moderate pancreatic fat deposition correlated with BMI and the presence of type 2 DM, but severe fat deposition did not correlate with them.

Use of Magnetic Resonance Imaging to Quantify Fat and Steatosis in the Pancreas in Patients after Bariatric Surgery: a Retrospective Study

INTRODUCTION

Pancreatic steatosis (PS) has both metabolic consequences and local effects on the pancreas itself. Magnetic resonance imaging (MRI) is the most reliable non-invasive method for diagnosing PS. We investigated the impact of metabolic syndrome (MS) on the presence of PS, differences in individuals with and without PS, and the metabolic effects of bariatric procedures.

METHODS

Changes in anthropometric and basic biochemistry values and MS occurrence were evaluated in 34 patients with obesity who underwent a bariatric procedure. After the procedure, patients underwent MRI with manual 3D segmentation mask creation to determine the pancreatic fat content (PFC). We compared the differences in the PFC and the presence of PS in individuals with and without MS and compared patients with and without PS.

RESULTS

We found no significant difference in the PFC between the groups with and without MS or in the occurrence of PS. There were significant differences in patients with and without PS, especially in body mass index (BMI), fat mass, visceral adipose tissue (VAT), select adipocytokines, and lipid spectrum with no difference in glycemia levels. Significant metabolic effects of bariatric procedures were observed.

CONCLUSIONS

Bariatric procedures can be considered effective in the treatment of obesity, MS, and some of its components. Measuring PFC using MRI did not show any difference in relation to MS, but patients who lost weight to BMI < 30 did not suffer from PS and had lower overall fat mass and VAT. Glycemia levels did not have an impact on the presence of PS.

An Isoenergetic Multifactorial Diet Reduces Pancreatic Fat and Increases Postprandial Insulin Response in Patients With Type 2 Diabetes: A Randomized Controlled Trial

OBJECTIVE

To compare the effect of an isocaloric multifactorial diet with a diet rich in monounsaturated fatty acids (MUFA) and similar macronutrient composition on pancreatic fat (PF) and postprandial insulin response in type 2 diabetes (T2D).

RESEARCH DESIGN AND METHODS

According to a randomized controlled parallel-group design, 39 individuals with T2D, 35-75 years old, in satisfactory blood glucose control, were assigned to an 8 week isocaloric intervention with a multifactorial diet rich in MUFA, polyunsaturated fatty acids, fiber, polyphenols, and vitamins (n = 18) or a MUFA-rich diet (n = 21). Before/after the intervention, PF content was measured by the proton-density fat fraction using a three-dimensional mDIXON MRI sequence, and plasma insulin and glucose concentrations were measured over a 4 h test meal with a similar composition as the assigned diet.

RESULTS

After 8 weeks, PF significantly decreased after the multifactorial diet (from 15.7 ± 6.5% to 14.1 ± 6.3%; P = 0.024), while it did not change after the MUFA diet (from 17.1 ± 10.1% to 18.6 ± 10.6%; P = 0.139) with a significant difference between diets (P = 0.014). Postprandial glucose response was similar in the two groups. Early postprandial insulin response (incremental postprandial areas under the curve [iAUC0-120]) significantly increased with the multifactorial diet (from 36,340 ± 34,954 to 44,138 ± 31,878 pmol/L/min; P = 0.037), while it did not change significantly in the MUFA diet (from 31,754 ± 18,446 to 26,976 ± 12,265 pmol/L/min; P = 0.178), with a significant difference between diets (P = 0.023). Changes in PF inversely correlated with changes in early postprandial insulin response (r = -0.383; P = 0.023).

CONCLUSIONS

In patients with T2D, an isocaloric multifactorial diet, including several beneficial dietary components, markedly reduced PF. This reduction was associated with an improved postprandial insulin response.

Improvement of Pancreatic Steatosis and Indices of Insulin Resistance After Metabolic Surgery

Purpose

Obesity is associated with fat accumulation in ectopic sites such as the pancreas, the so-called pancreatic steatosis (PS). Bariatric surgery has been shown to be associated with reducing pancreatic fat. This study investigated the effect of laparoscopic sleeve gastrectomy (LSG) on pancreatic volume and its fat content and glucose homeostasis.

Methods

The study enrolled 54 patients subjected to LSG. Metabolic variables and pancreatic exocrine function were assessed immediately before surgery and 12 months after. MRI of the abdomen was performed to measure pancreatic fat content and its total volume and visceral adipose tissue (VAT).

Results

Surgery resulted in a significant reduction in body weight and BMI. HbA1c, fasting insulin, C-peptide levels, HOMA-IR, and Hs-CRP levels decreased significantly. Surgery resulted in significant improvement in lipid profile except for HDL-cholesterol and liver function tests. Total VAT volume decreased significantly. Total pancreas volume decreased by a mean of 9.0 cm³ (95% CI: 6.6–11.3). The median change of pancreatic fat was −26.1% (range: −55.6 to 58.3%). Pancreatic lipase decreased significantly (P < 0.001). There was a positive correlation between the percentage of total weight loss and decrease in pancreatic fat volume (r = 0.295, P = 0.030).

Conclusion

Weight loss after LSG is associated with a reduction of total VAT volume, total pancreatic volume, and pancreatic fat content. These changes are associated with improved glucose homeostasis, reduced systemic inflammation, and decreased pancreatic lipase secretion.

Uniting epidemiology and experimental models: pancreatic steatosis and pancreatic cancer

Research from epidemiologic studies and experimental animal models provide insights into the role of pancreatic steatosis in the development of pancreatic cancer. Epidemiologic data demonstrate that pancreatic steatosis is widely prevalent and significantly associated with both development and progression of pancreatic cancer. By focusing on current experimental models, this review elucidates potential cellular mechanisms underlying not only the pathophysiology of pancreatic steatosis itself, but also the pathogenesis behind pancreatic steatosis's role in changing the tumour microenvironment and accelerating the development of pancreatic cancer. This review further explores the impact of bariatric surgery on pancreatic steatosis and pancreatic cancer. Synthesizing knowledge from both epidemiologic studies and experimental animal models, this review identifies gaps in current knowledge regarding pancreatic steatosis and its role in carcinogenesis and proposes future research directions to elucidate the possible mechanisms underlying other obesity-associated cancers.

Fatty Pancreas-Centered Metabolic Basis of Pancreatic Adenocarcinoma: From Obesity, Diabetes and Pancreatitis to Oncogenesis

Pancreatic ductal adenocarcinoma (PDAC) is one of the deadliest types of cancer, and it is currently the third most common cause of cancer death in the U.S.A. Progress in the fight against PDAC has been hampered by an inability to detect it early in the overwhelming majority of patients, and also by the reduced oxygen levels and nutrient perfusion caused by new matrix formation through the activation of stromal cells in the context of desmoplasia. One harbinger of PDAC is excess intrapancreatic fat deposition, namely, fatty pancreas, which specifically affects the tumor macro- and microenvironment in the organ. Over half of PDAC patients have diabetes mellitus (DM) at the time of diagnosis, and fatty pancreas is associated with subsequent DM development. Moreover, there is a strong association between fatty pancreas and fatty liver through obesity, and a higher intrapancreatic fat percentage has been noted in acute pancreatitis patients with DM than in those without DM. All these findings suggest that the link between fatty pancreas and PDAC might occur through metabolic alterations, either DM-related or non-DM-related. Based on clinical, in vivo and in vitro evidence, the current review highlights the etiologies of fatty pancreas (including fatty infiltration and replacement) and the fatty pancreas-associated metabolic alterations involved in oncogenesis to provide crucial targets to prevent, detect, and/or effectively treat PDAC.

Impact of pancreatic fat on the risk of post-endoscopic retrograde cholangiopancreatography pancreatitis

BACKGROUND AND STUDY AIMS

Fatty pancreas is a potential risk factor for acute pancreatitis; however, whether it is also a risk factor for post-endoscopic retrograde cholangiopancreatography pancreatitis (PEP) has not been evaluated. We aimed to determine the impact of fatty pancreas on the development of PEP.

METHODS

We analyzed the data of patients who underwent abdominal computed tomography (CT) scan and sequential therapeutic endoscopic retrograde cholangiopancreatography (ERCP). Fatty change in the pancreas was evaluated based on pancreatic attenuation of unenhanced image on CT scan. The risk of fatty pancreas for the development of PEP was evaluated using a logistic regression model.

RESULTS

Of a total of 858 patients included in the study, 354 (41.3%) had fatty pancreas, while 504 (58.7%) did not have fatty pancreas. PEP developed in 28 patients (7.9%) in the fatty pancreas group and in 13 patients (2.6%) in the no fatty pancreas group. Fatty pancreas was significantly associated with the development of PEP (odds ratio [OR] [95% confidence interval [CI]] 2.38 [1.16-4.87]). A history of acute pancreatitis, female sex, difficult cannulation, and endoscopic papillary balloon dilation were also risk factors for the development of PEP. The risk for moderate-to-severe PEP development tended to be higher in the fatty pancreas group than in the no fatty pancreas group (OR [95% CI] 5.61 [0.63-49.62]).

CONCLUSIONS

Fatty pancreas is a significant risk factor for the development of PEP. Clinicians need to be aware of the risk of fatty pancreas for the development of PEP prior to performing ERCP.

Pancreatic Steatosis Is Associated with Both Metabolic Syndrome and Pancreatic Stiffness Detected by Ultrasound Elastography

INTRODUCTION

There is increasing evidence that pancreatic steatosis (PS) is associated with metabolic syndrome (MS). However, it is not known whether it is associated with PS grade and pancreatic stiffness, or not. We aimed to evaluate the relationship between PS and its grade detected by transabdominal ultrasound, and pancreatic stiffness determined by two-dimensional shearwave elastography (2D-SWE), whether it has clinical significance and its relationship with MS.

METHODS

Patients with and without PS were evaluated prospectively.

RESULTS

Patients with PS had higher odds ratio for MS (OR 5.49). Also, ultrasonographic grade of PS was associated with MS parameters and hepatosteatosis. Pancreatic SWE value was significantly higher in PS group and positively correlated with PS grade, liver fat, MS, number of MS criteria.

DISCUSSION/CONCLUSION

PS and its grade were associated with MS. In this first comprehensive PS-SWE study, we found that pancreas stiffness increased in the presence of PS, in correlation with PS grade and MS.

Metabolic implications of pancreatic fat accumulation

Fat accumulation outside subcutaneous adipose tissue often has unfavourable effects on systemic metabolism. In addition to non-alcoholic fatty liver disease, which has received considerable attention, pancreatic fat has become an important area of research throughout the past 10 years. While a number of diagnostic approaches are available to quantify pancreatic fat, multi-echo Dixon MRI is currently the most developed method. Initial studies have shown associations between pancreatic fat and the metabolic syndrome, impaired glucose metabolism and type 2 diabetes mellitus. Pancreatic fat is linked to reduced insulin secretion, at least under specific circumstances such as prediabetes, low BMI and increased genetic risk of type 2 diabetes mellitus. This Review summarizes the possible causes and metabolic consequences of pancreatic fat accumulation. In addition, potential therapeutic approaches for addressing pancreatic fat accumulation are discussed.

Nonalcoholic Fatty Pancreas Disease: Role in Metabolic Syndrome, "Prediabetes," Diabetes and Atherosclerosis

Fat accumulation in the pancreas associated with obesity and the metabolic syndrome (MetS) has been defined as "non-alcoholic fatty pancreas disease" (NAFPD). The aim of this review is to describe the association of NAFPD with obesity, MetS, type 2 diabetes mellitus (T2DM) and atherosclerosis and also increase awareness regarding NAFPD. Various methods are used for the detection and quantification of pancreatic fat accumulation that may play a significant role in the differences that have been observed in the prevalence of NAFPD. Endoscopic ultrasound provides detailed images of the pancreas and its use is expected to increase in the future. Obesity and MetS have been recognized as NAFPD risk factors. NAFPD is strongly associated with non-alcoholic fatty liver disease (NAFLD) and it seems that the presence of both may be related with aggravation of NAFLD. A role of NAFPD in the development of "prediabetes" and T2DM has also been suggested by most human studies. Accumulation of fat in pancreatic tissue possibly initiates a vicious cycle of beta-cell deterioration and further pancreatic fat accumulation. Additionally, some evidence indicates a correlation between NAFPD and atherosclerotic markers (e.g., carotid intima-media thickness). Weight loss and bariatric surgery decreases pancreatic triglyceride content but pharmacologic treatments for NAFPD have not been evaluated in specifically designed studies. Hence, NAFPD is a marker of local fat accumulation possibly associated with beta-cell function impairment, carbohydrate metabolism disorders and atherosclerosis.

Quantitative Analysis of Pancreatic Fat in Children with Obesity Using Magnetic Resonance Imaging and Ultrasonography

PURPOSE

The aim of this study was to evaluate the pancreatic fat fraction (PFF) using magnetic resonance imaging (MRI) in children with and without obesity and to correlate PFF with body mass index (BMI) z-score, hepatic fat fraction (HFF), and ultrasonography-derived pancreato-perihepatic fat index (PPHFI).

METHODS

This prospective study included 45 children with obesity and 19 without obesity (control group). PFF and HFF were quantitatively assessed using the abdominal multi-echo Dixon method for MRI. The PPHFI was assessed using transabdominal ultrasonography. Anthropometric, MRI, and ultrasonographic characteristics were compared between the two groups. Correlations between PFF, HFF, PPHFI, and BMI z-scores in each group were also analyzed.

RESULTS

The PFF, HFF, PPHFI, and BMI z-score were higher in the group with obesity than in the control group (PFF: 6.65±3.42 vs. 1.78±0.55, HFF: 19.5±13.0 vs. 2.31±1, PPHFI: 3.65 ±1.63 vs. 0.94±0.31, BMI z-score: 2.27±0.56 vs. 0.42±0.54, p<0.01, respectively). PFF was correlated with BMI z-scores, PPHFI, and HFF in the obesity group, and multivariate analysis showed that PFF was strongly correlated with BMI z-score and PPHFI (p<0.05). The BMI z-score was strongly correlated with PFF in the control group (p<0.01).

CONCLUSION

These results suggest that MRI-derived PFF measures are associated with childhood obesity. PFF and PPHFI were also highly correlated in the obesity group. Therefore, PFF may be an objective index of pancreatic fat content and has the potential for clinical utility as a non-invasive biomarker for the assessment of childhood obesity.

The effects of in utero exposure to teratogens on organ size: a prospective paediatric study

In low-income countries, prospective data on combined effects of in utero teratogen exposure are lacking and necessitates new research. The aim of the present study was to explore the effect of in utero teratogen exposure on the size of the kidneys and pancreas 5 years after birth in a low-income paediatric population. Data was collected from 500 mother-child pairs from a low-income setting. Anthropometric measurements included body weight, (BW) body height, mid-upper arm and waist circumference (WC). Clinical measurements included blood pressure (BP), mean arterial pressure and heart rate. Ultrasound measurements included pancreas, and kidney measurements at age 5 years. The main outcome of interest was the effect of maternal smoking and alcohol consumption on ultrasound measurements of organ size at age 5 years. Left and right kidney length measurements were significantly lower in smoking exposed children compared to controls (p = 0.04 and p = 0.03). Pancreas body measurements were significantly lower in smoking exposed children (p = 0.04). Multiple regression analyses were used to examine the associations between the independent variables (IDVs), maternal age, body mass index (BMI), mid-upper arm circumference (MUAC) and BW of the child, on the dependent variables (DVs) kidney lengths and kidney volumes. Also, the association between in utero exposure to alcohol and nicotine and pancreas size. WC was strongest (r = 0.28; p < 0.01) associated with pancreas head [F (4, 454) = 13.44; R2 = 0.11; p < 0.01] and tail (r = 0.30; p < 0.01) measurements at age 5 years, with in utero exposure, sex of the child and BMI as covariates. Kidney length and pancreas body measurements are affected by in utero exposure to nicotine at age 5 years and might contribute to cardiometabolic risk in later life. Also, findings from this study report on ultrasound reference values for kidney and pancreas measurements of children at age 5 years from a low-income setting.

The β Cell in Diabetes: Integrating Biomarkers With Functional Measures

The pathogenesis of hyperglycemia observed in most forms of diabetes is intimately tied to the islet β cell. Impairments in propeptide processing and secretory function, along with the loss of these vital cells, is demonstrable not only in those in whom the diagnosis is established but typically also in individuals who are at increased risk of developing the disease. Biomarkers are used to inform on the state of a biological process, pathological condition, or response to an intervention and are increasingly being used for predicting, diagnosing, and prognosticating disease. They are also proving to be of use in the different forms of diabetes in both research and clinical settings. This review focuses on the β cell, addressing the potential utility of genetic markers, circulating molecules, immune cell phenotyping, and imaging approaches as biomarkers of cellular function and loss of this critical cell. Further, we consider how these biomarkers complement the more long-established, dynamic, and often complex measurements of β-cell secretory function that themselves could be considered biomarkers.

Nonalcoholic fatty pancreas disease: An emerging clinical challenge

Nonalcoholic fatty pancreas disease (NAFPD) is an emerging disease that has gained an increasing amount of attention in recent years. It describes fat accumulation in the pancreas with insignificant alcohol consumption, but the pathogenesis is largely unknown. A wide range of terms have been used to describe the phenomenon of pancreatic fat accumulation, but NAFPD remains an under-recognized and non-independent disorder. Obesity, age, sex, race, and unhealthy lifestyle are established independent risk factors for NAFPD, which is strongly associated with metabolic syndrome, type 2 diabetes, pancreatitis, pancreatic fistula, pancreatic cancer, and nonalcoholic fatty liver disease. At present, imaging techniques are common diagnostic aids, but uniform criteria and consensus are lacking. Therapeutically, healthy diet, weight loss, and exercise are the mainstays to reduce pancreatic fat accumulation. It can be seen that there is a limited understanding of NAFPD at this stage and further exploration is needed. Previous studies have revealed that NAFPD may directly affect diagnosis and clinical decision-making. Therefore, exploring the pathophysiological mechanism and clinical associations of NAFPD is a major challenge for researchers and clinicians.

Genome-wide association study of pancreatic fat: The Multiethnic Cohort Adiposity Phenotype Study

Several studies have found associations between higher pancreatic fat content and adverse health outcomes, such as diabetes and the metabolic syndrome, but investigations into the genetic contributions to pancreatic fat are limited. This genome-wide association study, comprised of 804 participants with MRI-assessed pancreatic fat measurements, was conducted in the ethnically diverse Multiethnic Cohort-Adiposity Phenotype Study (MEC-APS). Two genetic variants reaching genome-wide significance, rs73449607 on chromosome 13q21.2 (Beta = -0.67, P = 4.50x10-8) and rs7996760 on chromosome 6q14 (Beta = -0.90, P = 4.91x10-8) were associated with percent pancreatic fat on the log scale. Rs73449607 was most common in the African American population (13%) and rs79967607 was most common in the European American population (6%). Rs73449607 was also associated with lower risk of type 2 diabetes (OR = 0.95, 95% CI = 0.89-1.00, P = 0.047) in the Population Architecture Genomics and Epidemiology (PAGE) Study and the DIAbetes Genetics Replication and Meta-analysis (DIAGRAM), which included substantial numbers of non-European ancestry participants (53,102 cases and 193,679 controls). Rs73449607 is located in an intergenic region between GSX1 and PLUTO, and rs79967607 is in intron 1 of EPM2A. PLUTO, a lncRNA, regulates transcription of an adjacent gene, PDX1, that controls beta-cell function in the mature pancreas, and EPM2A encodes the protein laforin, which plays a critical role in regulating glycogen production. If validated, these variants may suggest a genetic component for pancreatic fat and a common etiologic link between pancreatic fat and type 2 diabetes.

Pancreatic enzymes and abdominal adipose tissue distribution in new-onset prediabetes/diabetes after acute pancreatitis

BACKGROUND

New-onset prediabetes/diabetes after acute pancreatitis (NODAP) is the most common sequela of pancreatitis, and it differs from type 2 prediabetes/diabetes mellitus (T2DM).

AIM

To study the associations between circulating levels of pancreatic amylase, pancreatic lipase, chymotrypsin and fat phenotypes in NODAP, T2DM, and health.

METHODS

Individuals with NODAP (n = 30), T2DM (n = 30), and sex-matched healthy individuals (n = 30) were included. Five fat phenotypes (intra-pancreatic fat, liver fat, skeletal muscle fat, visceral fat, and subcutaneous fat) were determined using the same magnetic resonance imaging protocol and scanner magnet strength for all participants. One-way analysis of covariance, linear regression analysis, and relative importance analysis were conducted.

RESULTS

Intra-pancreatic fat deposition (IPFD) was higher in NODAP (9.4% ± 1.8%) and T2DM (9.8% ± 1.1%) compared with healthy controls (7.8% ± 1.9%) after adjusting for covariates (P = 0.003). Similar findings were observed in regards to visceral fat volume (P = 0.005), but not subcutaneous fat volume, liver fat, or skeletal muscle fat. Both IPFD (β = -2.201, P = 0.023) and visceral fat volume (β = -0.004, P = 0.028) were significantly associated with circulating levels of pancreatic amylase in NODAP, but not in T2DM or healthy individuals. Of the five fat phenotypes, IPFD explained the highest amount of variance in pancreatic amylase concentration (R² = 15.3% out of 41.2%). None of the phenotypes contributed meaningfully to the variance in pancreatic lipase or chymotrypsin.

CONCLUSION

Both NODAP and T2DM are characterized by increased IPFD and visceral fat volume. However, only NODAP is characterized by significant inverse associations between the two fat phenotypes and pancreatic amylase.

Does Nonalcoholic Pancreatic Steatosis Always Correlate with Nonalcoholic Fatty Liver Disease?

Purpose

To identify the correlation of nonalcoholic pancreatic steatosis (NAPS) with nonalcoholic fatty liver disease (NAFLD) in an outpatient group. Based on its metabolic and imaging properties, NAPS has been increasingly recognized in recent years; however, its interaction with NAFLD is still not clear.

Patients and Methods

In this cross-sectional observational study, 345 consecutive patients without any chronic illness who were referred to the senior radiologist for abdominal ultrasound (US) were included. The US report showed hepatic and pancreatic echogenicity. The patients’ demographic, anthropometric, and laboratory data were collected from medical records.

Results

Overall, NAPS and NAFLD were seen in 227 (65.8%) and 219 (63.5%) patients, respectively. Normal echogenicity was noted in 74 (21.4%) patients. Forty-four patients (12.8%) had steatotic liver without NAPS, 52 (15.1%) had steatotic pancreas without NAFLD, and 175 (50.7%) had steatosis in both organs. The discordance in steatosis grading between NAPS and NAFLD was 55.1%. Insulin resistance was present in 8.7, 26.7, 19, and 61.3% of patients with no steatosis, only NAFLD, only NAPS, and steatosis in both organs, respectively. Evident NAFLD and NAPS having grade 2 and 3 steatosis were present in 15.3% and 29.0% of the study group, respectively. Cholecystolithiasis was present in 6.8, 13.6, and 28.8% of patients with normal echogenic pancreas, only NAFLD, and only NAPS, respectively (p=0.01).

Conclusion

Based on the ultrasonographic, clinical, demographic, and anthropometric features of the included patients, we found that NAPS did not fully accompany nonalcoholic fatty liver. Despite severe pancreatic steatosis, more than a quarter of cases had normal liver echogenicity. Insulin resistance frequency was insignificantly higher in NAFLD than NAPS (p=0.694). The significantly higher frequency of cholecystolithiasis in NAPS needs further large-scale studies. The inconsistency of steatosis degree in NAPS and NAFLD in >50% cases may reflect differences in the pathophysiology of these two clinical entities.

Pancreatic steatosis in adult rats induced by nicotine exposure during breastfeeding

PURPOSE

Maternal nicotine exposure negatively impacts offspring's health and metabolism, leading to obesity and insulin resistance. Here we investigated the pancreatic islet function, glycemic homeostasis, and insulin signaling in adult rat offspring that were nicotine-exposed during breastfeeding.

METHODS

For this, lactating Wistar rat dams were divided into two groups: Nicotine (implanted with osmotic minipumps containing 6 mg/Kg, NIC) and Control (saline, CON). Solutions were released from postnatal (PN) day 2-16. At PN110 and PN170, 10 offspring per litter/sex/group were submitted to the oral glucose tolerance test (OGTT). PN180 offspring were killed and glycemia, insulinemia, adiponectinemia, pancreas morphology as well as pancreatic islet protein expression (related to insulin secretion) and skeletal muscle (related to insulin action) were evaluated. Males and females were compared to their respective controls.

RESULTS

Adult NIC offspring of both sexes showed glucose intolerance in the OGTT. Despite normoglycemia, NIC males showed hyperinsulinemia while females, although normoinsulinemic, had hyperglycemia. Both sexes showed increased IRI, reduced adiponectin/visceral fat mass ratio and higher ectopic deposition of lipids in the pancreatic tissue adipocytes. In pancreatic islets, NIC males showed lower PDX-1 expression while females had higher PDX-1 and GLUT2 expressions plus lower α2 adrenergic receptor. In the muscle, NIC offspring of both sexes showed reduction of GLUT4 expression; NIC males also had lower insulin receptor and pAKT expressions.

CONCLUSIONS

Thus, glycemic homeostasis and peripheral insulin signaling in adult offspring of both sexes are affected by nicotine exposure through the milk, increasing the risk for type 2 diabetes development.

Effects of Ethanol Extracts from Grateloupia elliptica, a Red Seaweed, and Its Chlorophyll Derivative on 3T3-L1 Adipocytes: Suppression of Lipid Accumulation through Downregulation of Adipogenic Protein Expression

Grateloupia elliptica (G. elliptica) is a red seaweed with antioxidant, antidiabetic, anticancer, anti-inflammatory, and anticoagulant activities. However, the anti-obesity activity of G. elliptica has not been fully investigated. Therefore, the effect of G. elliptica ethanol extract on the suppression of intracellular lipid accumulation in 3T3-L1 cells by Oil Red O staining (ORO) was evaluated. Among the eight red seaweeds tested, G. elliptica 60% ethanol extract (GEE) exhibited the highest inhibition of lipid accumulation. GEE was the only extract to successfully suppress lipid accumulation among ethanol extracts from eight red seaweeds. In this study, we successfully isolated chlorophyll derivative (CD) from the ethyl acetate fraction (EA) of GEE by high-performance liquid chromatography and evaluated their inhibitory effect on intracellular lipid accumulation in 3T3-L1 adipocytes. CD significantly suppressed intracellular lipid accumulation. In addition, CD suppressed adipogenic protein expression such as sterol regulatory element-binding protein-1 (SREBP-1), peroxisome proliferator-activated receptor-γ (PPAR-γ), CCAAT/enhancer-binding protein-α (C/EBP-α), and fatty acid binding protein 4 (FABP4). Taken together, our results indicate that CD from GEE inhibits lipid accumulation by suppressing adipogenesis via the downregulation of adipogenic protein expressions in the differentiated adipocytes. Therefore, chlorophyll from G. elliptica has a beneficial effect on lipid metabolism and it could be utilized as a potential therapeutic agent for preventing obesity.

Pancreas Optical Clearing and 3-D Microscopy in Health and Diabetes

Although first described over a hundred years ago, tissue optical clearing is undergoing renewed interest due to numerous advances in optical clearing methods, microscopy systems, and three-dimensional (3-D) image analysis programs. These advances are advantageous for intact mouse tissues or pieces of human tissues because samples sized several millimeters can be studied. Optical clearing methods are particularly useful for studies of the neuroanatomy of the central and peripheral nervous systems and tissue vasculature or lymphatic system. Using examples from solvent- and aqueous-based optical clearing methods, the mouse and human pancreatic structures and networks will be reviewed in 3-D for neuro-insular complexes, parasympathetic ganglia, and adipocyte infiltration as well as lymphatics in diabetes. Optical clearing with multiplex immunofluorescence microscopy provides new opportunities to examine the role of the nervous and circulatory systems in pancreatic and islet functions by defining their neurovascular anatomy in health and diabetes.

The relation of CT quantified pancreatic fat index with visceral adiposity and hepatic steatosis

Objectives

The purpose of this study was to investigate the relation between pancreatic steatosis and visceral adiposity. Furthermore, the study sought to explore the association between pancreatic steatosis, pancreas volume, hepatic steatosis, age, and sex in adults without prior history of pancreatic disease. The research also served to define a cut-off value of visceral fat tissue area (VFA) predicting fatty pancreas.

Material and Methods

CT scans of 98 living-liver donor transplant patients without prior history of pancreatic disease were evaluated for the presence of fatty pancreas. Pancreas volume, VFA, subcutaneous-total FA, VFA/TFA ratios of the patients with and without fatty pancreas were quantified with a semi-automated model on CT. Coexistence of hepatic steatosis was also recorded.

Results

VFA, TFA and VFA/TFA were significantly greater in the fatty group (p<0.001, p<0.001, p<0.001; respectively), and pancreatic steatosis was moderately correlated with VFA, VFA/TFA and TFA with the highest correlation coefficient with VFA (r=-0.715, r=-0.605, r=-0.573, respectively; p<0.001 for all). A cut-off value of VFA ≥ 107.2 cm2 estimates pancreatic steatosis with a sensitivity and specificity of 90% (95% CI=77-96%) and 87.9% (95% CI=77%-94%), respectively. Pancreas volume was higher in the fatty-group with a mean value of 86.5±17.3 mL (range; 58-119.2 mL, p=0.097). In multiple logistic regression analyses, pancreatic steatosis was significantly associated with VFA and the male sex (OR=58.2, 95% CI=12.2-277.1, p<0.001; OR=11.4, 95% CI=2.1-63.4, p<0.001; respectively). 77.5% of the fatty pancreas subjects had co-existing hepatic steatosis.

Conclusion

Pancreatic steatosis is related to higher VFA, VFA/TFA and hepatic steatosis. A cut-off value of VFA ≥ 107.2 cm² may predict pancreatic steatosis.

The relationship between pancreas steatosis and the risk of metabolic syndrome and insulin resistance in Chinese adolescents with concurrent obesity and non-alcoholic fatty liver disease

BACKGROUND

The incidence of childhood obesity and associated comorbidities are on an increasing trend worldwide. More than 340 million children and adolescents aged between 5 and 19 years old were overweight or had obesity in 2016, from which over 124 million children and adolescents (6% of girls and 8% of boys) had obesity.

OBJECTIVE

To describe the relationship between pancreas steatosis, body fat and the risk of metabolic syndrome, insulin resistance in Hong Kong Chinese adolescents with both obesity and non-alcoholic fatty liver disease (NAFLD).

METHODS

Fifty two adolescents with obesity and NAFLD were analysed (14-18 years), stratified into fatty and non-fatty pancreas groups using chemical shift encoded MRI-pancreas proton density fat fraction ≥5%. Pancreatic, abdominal subcutaneous adipose tissue (SAT)/visceral adipose tissue (VAT) volumes, biochemical and anthropometric parameters were measured. Mann-Whitney U test, multiple linear/binary logistic regression analyses and odds ratios were used.

RESULTS

Fifty percent had fatty pancreas, 38% had metabolic syndrome and 81% had insulin resistance. Liver proton density fat fraction (PDFF) and VAT were independent predictors of insulin resistance (P = .006, .016). Pancreas and liver PDFF were both independent predictors of beta cells dysfunction (P = .015, .050) and metabolic syndrome (P = .021, .041). Presence of fatty pancreas in obesity was associated with insulin resistance (OR = 1.58, 95% CI = 0.39-6.4) and metabolic syndrome (OR = 1.70, 95% CI = 0.53-5.5).

CONCLUSION

A significant causal relationship exists between fatty pancreas, fatty liver, body fat and the risk of developing metabolic syndrome and insulin resistance.

KEY POINTS

Fatty pancreas is a common finding in adolescents with obesity, with a prevalence rate of 50% in this study cohort. Liver PDFF and VAT are independent predictors of insulin resistance while pancreas PDFF and liver PDFF are independent predictors of both beta cells dysfunction and metabolic syndrome. Presence of fatty pancreas at imaging should not be considered as a benign finding but rather as an imaging biomarker of emerging pancreatic metabolic and endocrine dysfunction.

Environmental Factors Slightly Outweigh Genetic Influences in the Development of Pancreatic Lipid Accumulation: A Classical Twin Study

Background: Several studies showed that lipid accumulation in the pancreas (NAFPD: nonalcoholic fatty pancreas disease) may lead to different pancreatic disorders, including beta-cell dysfunction. The role of genetic and environmental factors in pancreatic lipid accumulation is unclear. We evaluated the magnitude of genetic and environmental impact on pancreatic lipid content within a cohort of adult twin pairs. Patients and Methods: We investigated 136 twin subjects [monozygotic (MZ, n = 86) and dizygotic (DZ, n = 50) same-gender twins (age 57.7 ± 9.1 years; body mass index [BMI] 28.0 ± 4.4 kg/m²; females 64.7%)] with a 256-slice computed tomography (CT)-scanner. Using nonenhanced CT images, we calculated the average value of pancreatic attenuation expressed in Hounsfield unit (HU) suggesting pancreatic lipid content. Crude data were adjusted to age, sex, BMI, and hemoglobinA1c values. Intrapair correlations were established, and structural equation models were used for quantifying the contribution of additive genetic (A), common environmental (C), and unique environmental (E) components to the investigated phenotype. Results: The study cohort represented a moderately overweight, middle-aged Caucasian population. Average pancreatic attenuation was 48.9 ± 11.9 HU in MZ and 49.0 ± 13.0 HU in DZ twins (P = 0.934). The intrapair correlation between HU values was stronger in MZ compared to DZ twins (rMZ = 0.536, P < 0.001; rDZ = 0.115, P = 0.580). Using the structural equation model, a greater unique environmental influence [E: 54%, 95% confidence interval (CI) 19%-66%] and a moderate additive genetic dependence (A: 46%, 95% CI 34%-81%) were found. Conclusions: The results of our classical twin study indicate that environmental (lifestyle) influences slightly outweigh genetic effects on the phenotypic appearance of pancreatic lipid accumulation known as NAFPD.

Longitudinal association of fatty pancreas with the incidence of type-2 diabetes in lean individuals: a 6-year computed tomography-based cohort study

BACKGROUND

Only a few studies have longitudinally evaluated whether fatty pancreas increases the risk of type-2 diabetes (T2D), and their results were inconsistent. Fatty pancreas is closely linked to overweight and obesity, but previous studies did not exclude overweight or obese individuals. Therefore, in this cohort study, we investigated the association between fatty pancreas and T2D incidence in lean individuals.

METHODS

Between 2008 and 2013, 1478 nondiabetic lean individuals (i.e. body-mass index < 25 kg/m²) underwent health examinations including computed tomography (CT) and were followed for a median of 6.19 years. Fatty pancreas was evaluated by a histologically-validated method using pancreas attenuation (Hounsfield units [HU]) on CT at baseline; lower pancreas attenuation indicates more pancreatic fat. To detect incident T2D, we used fasting plasma glucose, HbA1c, and self-reports of prescribed anti-diabetes medications. Odds ratios (OR) for the association between pancreas attenuation and incident T2D were estimated using logistic regression models adjusted for likely confounders.

RESULTS

T2D occurred in 61 participants (4.13%) during the follow-up period. Lower pancreas attenuation (i.e. more pancreatic fat) at baseline was associated with incident T2D (unadjusted OR per 10 HU lower attenuation: 1.56 [95% CI 1.28-1.91], p < 0.001). The multivariable-adjusted analysis revealed a similar association (adjusted OR per 10 HU lower attenuation: 1.32 [95% CI 1.06-1.63], p = 0.012).

CONCLUSIONS

T2D was likely to develop in lean individuals with the fatty pancreas. Among people who are neither obese nor overweight, the fatty pancreas can be used to define a group at high risk for T2D.

Nonalcoholic Fatty Pancreas Disease

Nonalcoholic fatty pancreas disease (NAFPD) describes a phenotype of pancreatic steatosis (PS) that is not caused by alcohol consumption, viral infections, toxins, or congenital metabolic syndromes but is associated with insulin resistance, malnutrition, obesity, metabolic syndrome, or increasing age. NAFPD is a relatively new disease entity, as the clinical significance of fatty infiltration of pancreas has gained attention recently. Clinical consequences of NAFPD remain largely unknown despite clinical associations. This review aims to study similarities and differences between hepatic and PS and explore recent advances in NAFPD.

21st Century Advances in Multimodality Imaging of Obesity for Care of the Cardiovascular Patient

Although obesity is typically defined by body mass index criteria, this does not differentiate true body fatness, as this includes both body fat and muscle. Therefore, other fat depots may better define cardiometabolic and cardiovascular disease (CVD) risk imposed by obesity. Data from translational, epidemiological, and clinical studies over the past 3 decades have clearly demonstrated that accumulation of adiposity in the abdominal viscera and within tissue depots lacking physiological adipose tissue storage capacity (termed "ectopic fat") is strongly associated with the development of a clinical syndrome characterized by atherogenic dyslipidemia, hyperinsulinemia/glucose intolerance/type 2 diabetes mellitus, hypertension, atherosclerosis, and abnormal cardiac remodeling and heart failure. This state-of-the-art paper discusses the impact of various body fat depots on cardiometabolic parameters and CVD risk. Specifically, it reviews novel and emerging imaging techniques to evaluate adiposity and the risk of cardiometabolic diseases and CVD.

Quantitative pancreatic MRI: a pathology-based review

MRI plays an important role in the clinical management of pancreatic disorders and interpretation is reliant on qualitative assessment of anatomy. Conventional sequences capturing pancreatic structure can however be adapted to yield quantitative measures which provide more diagnostic information, with a view to increasing diagnostic accuracy, improving patient stratification, providing robust non-invasive outcome measures for therapeutic trials and ultimately personalizing patient care. In this review, we evaluate the use of established techniques such as secretin-enhanced MR cholangiopancreatography, diffusion-weighted imaging, T ₁, T ₂* and fat fraction mapping, but also more experimental methods such as MR elastography and arterial spin labelling, and their application to the assessment of diffuse pancreatic disease (including chronic, acute and autoimmune pancreatitis/IgG4 disease, metabolic disease and iron deposition disorders) and cystic/solid focal pancreatic masses. Finally, we explore some of the broader challenges to their implementation and future directions in this promising area.

Changes in Pancreatic Fat Content Following Diet-Induced Weight Loss

Background: Obesity can lead to ectopic pancreatic fat accumulation and increase the risk for type 2 diabetes. Smaller intervention trials have shown a decrease in pancreatic fat content (PFC) with weight loss, and we intended to investigate the effects of weight loss on PFC in a larger trial. Methods: Data from the HELENA-Trial, a randomized controlled trial (RCT) among 137 non-diabetic obese adults were used. The study cohort was classified into 4 quartiles based on weight change between baseline and 12 weeks post-intervention. Changes in PFC (baseline, 12 weeks and 50 weeks post-intervention) upon weight loss were analyzed by linear mixed models. Spearman’s coefficients were used to obtain correlations between anthropometric parameters, blood biochemical markers, and PFC. Results: At baseline, PFC only showed a significant correlation with visceral adipose tissue (VAT) (r = 0.41). Relative changes in PFC were significantly (p = 0.01) greater in Q4 (−30.8 ± 5.7%) than in Q1 (1.3 ± 6.7%). These differences remained similar after one year. However, when adjusting the statistical analyses for changes in VAT, the differences in PFC between Q1 and Q4 were no longer statistically significant. Conclusion: Weight loss is associated with a decrease in PFC. However, the reduction of PFC is not independent from reductions in VAT. Unlike VAT, PFC was not associated with metabolic biomarkers.

MRI assessment of ectopic fat accumulation in pancreas, liver and skeletal muscle in patients with obesity, overweight and normal BMI in correlation with the presence of central obesity and metabolic syndrome

Purpose: Obesity, defined as a body mass index (BMI) exceeding 30 kg/m², is a serious health problem, which can be called an epidemic on a global scale and is one of the most important causes of preventable death. The aim of this study was to assess ectopic fat accumulation in pancreas, liver and skeletal muscle in patients with obesity, overweight and normal BMI in correlation with metabolic syndrome (MetS). Patients and methods: The study included 267 consecutive patients who underwent a standard clinical assessment with BMI calculation. Ectopic fat accumulation in pancreas, liver, and skeletal muscle was evaluated by magnetic resonance imaging (MRI) using fat-water separated Dixon imaging. MetS was defined according to the criteria modified by the National Cholesterol Education Program Adult Treatment Panel III Guidelines. Central obesity was defined using gender and ethnic-specific values for waist circumference. Results: There was a statistically significant correlation between the degree of steatosis of the assessed organs and BMI value as well as waist circumference ratio, that determined the degree of central obesity. It was found that the most rapid relative fat accumulation was in muscle, then in pancreas and then in liver. Higher steatosis of pancreas, liver, and muscle was demonstrated depending on the number of the satisfied MetS criteria. Conclusion: Knowing that pancreatic fatty disease is a risk factor for MetS, it seems that assessment and monitoring of ectopic fat accumulation may have important clinical implications and may be used in the prediction of metabolic risk and its early prevention.