Ectopic Fat Accumulation Research Articles

A Short-Term High-Fat Diet Worsens Insulin Sensitivity with Changes in Metabolic Parameters in Non-Obese Japanese Men.

A short-term high-calorie high-fat diet (HCHFD) impairs insulin sensitivity in non-obese South Asian but not Caucasian men; however, the effect of short-term HCHFD on insulin sensitivity in East Asians is unknown. We recruited 21 healthy non-obese Japanese men to evaluate metabolic parameters and gut microbiota before and after 6-day HCHFD consisting of a regular diet plus a 45% energy excess with dairy fat supplementation. We evaluated tissue-specific insulin sensitivity and metabolic clearance rate of insulin (MCRI) using a two-step hyperinsulinemic euglycemic clamp, glucose tolerance using the glucose tolerance test, and measured ectopic fat in muscle and the liver using ¹H-magnetic resonance spectroscopy. The primary outcome of this study was insulin sensitivity measured by the clamp study. The secondary/exploratory outcomes were other metabolic changes. After HCHFD, levels of circulating lipopolysaccharide binding protein (LBP), a marker of endotoxemia, increased by 14%. In addition, intramyocellular lipid levels in the tibialis anterior and soleus and intrahepatic lipid levels increased by 47%, 31%, and 200%, respectively. Insulin sensitivity decreased by 4% in muscle and 8% in liver. However, even with reduced insulin sensitivity, glucose metabolism was maintained by increased serum insulin concentrations due to lower MCRI and higher endogenous insulin secretion during the clamp. Glucose levels during the meal tolerance test were comparable before and after HCHFD. In conclusion, short-term HCHFD impaired insulin sensitivity in the muscle and livers of non-obese Japanese men with increased LBP and ectopic fat accumulation. Elevated insulin levels from modulated insulin secretion and clearance might contribute to the maintenance of normal glucose metabolism during the clamp and meal tolerance test.

Cross-tissue omics analysis discovers ten adipose genes encoding secreted proteins in obesity-related non-alcoholic fatty liver disease.

Non-alcoholic fatty liver disease (NAFLD) is a fast-growing, underdiagnosed, epidemic. We hypothesise that obesity-related inflammation compromises adipose tissue functions, preventing efficient fat storage, and thus driving ectopic fat accumulation into the liver. To identify adipose-based mechanisms and potential serum biomarker candidates (SBCs) for NAFLD, we utilise dual-tissue RNA-sequencing (RNA-seq) data in adipose tissue and liver, paired with histology-based NAFLD diagnosis, from the same individuals in a cohort of obese individuals. We first scan for genes that are differentially expressed (DE) for NAFLD in obese individuals' subcutaneous adipose tissue but not in their liver; encode proteins secreted to serum; and show preferential adipose expression. Then the identified genes are filtered to key adipose-origin NAFLD genes by best subset analysis, knockdown experiments during human preadipocyte differentiation, recombinant protein treatment experiments in human liver HepG2 cells, and genetic analysis. We discover a set of genes, including 10 SBCs, that may modulate NAFLD pathogenesis by impacting adipose tissue function. Based on best subset analysis, we further follow-up on two SBCs CCDC80 and SOD3 by knockdown in human preadipocytes and subsequent differentiation experiments, which show that they modulate crucial adipogenesis genes, LPL, SREBPF1, and LEP. We also show that treatment of the liver HepG2 cells with the CCDC80 and SOD3 recombinant proteins impacts genes related to steatosis and lipid processing, including PPARA, NFE2L2, and RNF128. Finally, utilizing the adipose NAFLD DE gene cis-regulatory variants associated with serum triglycerides (TGs) in extensive genome-wide association studies (GWASs), we demonstrate a unidirectional effect of serum TGs on NAFLD with Mendelian Randomization (MR) analysis. We also demonstrate that a single SNP regulating one of the SBC genes, rs2845885, produces a significant MR result by itself. This supports the conclusion that genetically regulated adipose expression of the NAFLD DE genes may contribute to NAFLD through changes in serum TG levels. Our results from the dual-tissue transcriptomics screening improve the understanding of obesity-related NAFLD by providing a targeted set of 10 adipose tissue-active genes as new serum biomarker candidates for the currently grossly underdiagnosed fatty liver disease. The work was supported by NIH grants R01HG010505 and R01DK132775. The Genotype-Tissue Expression (GTEx) Project was supported by the Common Fund of the Office of the Director of the National Institutes of Health, and by NCI, NHGRI, NHLBI, NIDA, NIMH, and NINDS. The KOBS study (J. P.) was supported by the Finnish Diabetes Research Foundation, Kuopio University Hospital Project grant (EVO/VTR grants 2005-2019), and the Academy of Finland grant (Contract no. 138006). This study was funded by the European Research Council under the European Union's Horizon 2020 research and innovation program (Grant No. 802825 to M. U. K.). K. H. P. was funded by the Academy of Finland (grant numbers 272376, 266286, 314383, and 335443), the Finnish Medical Foundation, Gyllenberg Foundation, Novo Nordisk Foundation (grant numbers NNF10OC1013354, NNF17OC0027232, and NNF20OC0060547), Finnish Diabetes Research Foundation, Finnish Foundation for Cardiovascular Research, University of Helsinki, and Helsinki University Hospital and Government Research Funds. I. S. was funded by the Instrumentarium Science Foundation. Personal grants to U. T. A. were received from the Matti and Vappu Maukonen Foundation, Ella och Georg Ehrnrooths Stiftelse and the Finnish Foundation for Cardiovascular Research.

ASSESSMENT OF INSULIN RESISTANCE IN NONALCOHOLIC FATTY LIVER DISEASE IN NON-DIABETIC PATIENTS

Background: Non-alcoholic fatty liver disease (NAFLD) refers to a spectrum of liver damage ranging from simple steatosis to nonalcoholic steatohepatitis (NASH). The ectopic accumulation of fat in the liver has been strongly associated with insulin resistance. To Aim of the study: explore the proportion of insulin resistance in non-diabetic NAFLD patients compared to normal healthy populations using HOMA-IR model. Materials and Methods: This was a hospital based case control study carried out on 100 patients diagnosed with NAFLD by ultrasound. Fasting Insulin estimation was done by Insulin IRMA (IMMUNORADIOMETRIC ASSAY) Kit. P Results: atients with NAFLD had a higher prevalence (33%) of metabolic syndrome than the controls (15%) with an Odds Ratio of 2.791. Insulin resistance in non-diabetic NAFLD patients was higher (36%) than the control populations (11%) (p value was <0.001). This study has shown that insuli Conclusion: n resistance has a positive association with NAFLD

Obesity and Type 2 Diabetes: Adiposopathy as a Triggering Factor and Therapeutic Options

Obesity and type 2 diabetes (T2DM) are major public health concerns associated with serious morbidity and increased mortality. Both obesity and T2DM are strongly associated with adiposopathy, a term that describes the pathophysiological changes of the adipose tissue. In this review, we have highlighted adipose tissue dysfunction as a major factor in the etiology of these conditions since it promotes chronic inflammation, dysregulated glucose homeostasis, and impaired adipogenesis, leading to the accumulation of ectopic fat and insulin resistance. This dysfunctional state can be effectively ameliorated by the loss of at least 15% of body weight, that is correlated with better glycemic control, decreased likelihood of cardiometabolic disease, and an improvement in overall quality of life. Weight loss can be achieved through lifestyle modifications (healthy diet, regular physical activity) and pharmacotherapy. In this review, we summarized different effective management strategies to address weight loss, such as bariatric surgery and several classes of drugs, namely metformin, GLP-1 receptor agonists, amylin analogs, and SGLT2 inhibitors. These drugs act by targeting various mechanisms involved in the pathophysiology of obesity and T2DM, and they have been shown to induce significant weight loss and improve glycemic control in obese individuals with T2DM.

FGF signaling promotes spreading of fat body precursors necessary for adult adipogenesis in Drosophila.

Knowledge of adipogenetic mechanisms is essential to understand and treat conditions affecting organismal metabolism and adipose tissue health. In Drosophila, mature adipose tissue (fat body) exists in larvae and adults. In contrast to the well-known development of the larval fat body from the embryonic mesoderm, adult adipogenesis has remained mysterious. Furthermore, conclusive proof of its physiological significance is lacking. Here, we show that the adult fat body originates from a pool of undifferentiated mesodermal precursors that migrate from the thorax into the abdomen during metamorphosis. Through in vivo imaging, we found that these precursors spread from the ventral midline and cover the inner surface of the abdomen in a process strikingly reminiscent of embryonic mesoderm migration, requiring fibroblast growth factor (FGF) signaling as well. FGF signaling guides migration dorsally and regulates adhesion to the substrate. After spreading is complete, precursor differentiation involves fat accumulation and cell fusion that produces mature binucleate and tetranucleate adipocytes. Finally, we show that flies where adult adipogenesis is impaired by knock down of FGF receptor Heartless or transcription factor Serpent display ectopic fat accumulation in oenocytes and decreased resistance to starvation. Our results reveal that adult adipogenesis occurs de novo during metamorphosis and demonstrate its crucial physiological role.

Roles and heterogeneity of mesenchymal progenitors in muscle homeostasis, hypertrophy, and disease.

Skeletal muscle is mainly composed of multinucleated cells called myofibers, and has excellent regenerative and adaptive abilities. These abilities are granted by muscle satellite cells (MuSCs), which are anatomically defined cells located between myofibers and basal lamina. In addition to myofibers and MuSCs, skeletal muscle contains several types of cells located in interstitial areas, such as mesenchymal progenitors. These cells are positive for platelet-derived growth factor receptor alpha and are called fibro/adipogenic progenitors (FAPs) or mesenchymal stromal cells. Although mesenchymal progenitors were originally identified as the causative cells of ectopic fat accumulation in skeletal muscles, recent studies have shed light on their beneficial roles in homeostasis, regeneration, and hypertrophy. Furthermore, the heterogeneity of mesenchymal progenitors is of great interest in understanding skeletal muscle development, homeostasis, regeneration, aging, and diseases. In this concise review, we summarize recent findings on the physiological roles of mesenchymal progenitors and their heterogeneity and discuss the remaining critical concerns.

A79 THE RELATIONSHIP BETWEEN VISCERAL ADIPOSITY AND NONALCOHOLIC FATTY LIVER DISEASE DIAGNOSED BY CONTROLLED ATTENUATION PARAMETER IN PEOPLE WITH HIV: A PILOT STUDY

Abstract Background Aging people with HIV (PWH) on antiretroviral therapy face high rates of metabolic dysfunction and nonalcoholic fatty liver disease (NAFLD). Fat alterations are frequent in PWH and predict worse cardiometabolic outcomes. Visceral adipose tissue (VAT) is an important compartment of body fat tissue releasing bioactive molecules. As a hormonally active tissue, VAT critically contributes to obesity-related disorders and is associated with ectopic fat accumulation in the liver. Purpose We aimed to investigate NAFLD diagnosed by controlled attenuation parameter (CAP) as a marker of visceral adiposity in PWH. Method We conducted a prospective pilot study (ClinicalTrials.gov 2021-6656) of HIV mono-infected patients undergoing metabolic characterization and paired CAP by transient elastography with dual-energy X-ray absorptiometry (DEXA) scan. NAFLD was defined as CAP ≥285 dB/m, in absence of alcohol abuse. Excess visceral adiposity was defined as VAT>1.32 Kg. Pairwise correlation, area under the curve (AUC) and logistic regression analysis were employed to study the association between VAT and CAP. Result(s) 30 patients (90% male, mean age 48.5, mean BMI 29.9, mean waist circumference 100.9, 50% with NAFLD) were included. When compared to those without excess VAT, PWH with excess VAT were older (53+12 vs 43+13 years, p=0.035), had longer duration of HIV infection (20+13 vs. 9+9 years, p=0.021), had higher BMI (32+4 vs 27+4 Kg/m2, p=0.002) and waist circumference (107+11 vs. 93+12 cm, p=0.004). They also had more history of cardiovascular events (29% vs. 0, p=0.032) and higher lipid accumulation product, a marker of lipid accumulation based on waist circumference and triglycerides (112+53 vs. 38+27, p<0.001). CAP was higher in PWH with excess VAT (319+52 vs. 213+52 dB/m, p<0.001). CAP positively correlated with all visceral fat measurements by DEXA, including VAT (r=0.650, p<0.001), VAT/body weight ratio (r=0.565, p=0.001) and fat mass (r=0.390, p=0.033). Both BMI and waist circumference showed correlation with VAT and fat mass, but not with VAT/body weight ratio (see Figure). After adjusting for duration of HIV infection (aOR 1.01 per year, 95% CI 0.91-1.12; p=0.921), BMI (aOR 1.77, 95% CI 0.74-4.23; p=0.202) and waist circumference (aOR 0.91 per cm, 95% 0.68-1.21; p=0.509), CAP remained the only independent predictor of excess VAT (aOR 1.05 per dB/m, 95% CI 1.01-1.10; p=0.036). The AUC analysis determined CAP had excellent performance to diagnose excess VAT (AUC 0.92, 95% CI 0.81-1.00), higher than BMI (AUC 0.83, 95% CI 0.68-0.99) and waist circumference (AUC 0.81, 95% CI 0.65-0.97). The optimized CAP cut-off to diagnose excess VAT was 266 dB/m, with a sensitivity of 88.3% and a specificity of 84.6%. Image Conclusion(s) NAFLD diagnosed by CAP is associated with VAT in PWH independently of anthropometric measures of obesity. CAP could be used as a diagnostic marker of visceral adiposity in the practice of HIV medicine Please acknowledge all funding agencies by checking the applicable boxes below Other Please indicate your source of funding; CanHepC Disclosure of Interest W. Elgretli Grant / Research support from: CanHepC, N. Paisible: None Declared, C. Costiniuk: None Declared, J. Cox: None Declared, D. Kablawi: None Declared, M. Klein: None Declared, N. Kronfli: None Declared, J.-P. Routy: None Declared, J. Falutz: None Declared, B. Lebouche: None Declared, G. Guaraldi: None Declared, G. Sebastiani: None Declared

Hypolipidemic Effects of Beetroot Juice in SHR-CRP and HHTg Rat Models of Metabolic Syndrome: Analysis of Hepatic Proteome

Recently, red beetroot has attracted attention as a health-promoting functional food. Studies have shown that beetroot administration can reduce blood pressure and ameliorate parameters of glucose and lipid metabolism; however, mechanisms underlying these beneficial effects of beetroot are not yet fully understood. In the current study, we analysed the effects of beetroot on parameters of glucose and lipid metabolism in two models of metabolic syndrome: (i) transgenic spontaneously hypertensive rats expressing human C-reactive protein (SHR-CRP rats), and (ii) hereditary hypertriglyceridemic (HHTg) rats. Treatment with beetroot juice for 4 weeks was, in both models, associated with amelioration of oxidative stress, reduced circulating lipids, smaller visceral fat depots, and lower ectopic fat accumulation in the liver compared to the respective untreated controls. On the other hand, beetroot treatment had no significant effects on the sensitivity of the muscle and adipose tissue to insulin action in either model. Analyses of hepatic proteome revealed significantly deregulated proteins involved in glycerophospholipid metabolism, mTOR signalling, inflammation, and cytoskeleton rearrangement.

Oxidative Stress Modulation by ncRNAs and Their Emerging Role as Therapeutic Targets in Atherosclerosis and Non-Alcoholic Fatty Liver Disease.

Atherosclerosis and non-alcoholic fatty liver disease (NAFLD) are pathologies related to ectopic fat accumulation, both of which are continuously increasing in prevalence. These threats are prompting researchers to develop effective therapies for their clinical management. One of the common pathophysiological alterations that underlies both diseases is oxidative stress (OxS), which appears as a result of lipid deposition in affected tissues. However, the molecular mechanisms that lead to OxS generation are different in each disease. Non-coding RNAs (ncRNAs) are RNA transcripts that do not encode proteins and function by regulating gene expression. In recent years, the involvement of ncRNAs in OxS modulation has become more recognized. This review summarizes the most recent advances regarding ncRNA-mediated regulation of OxS in atherosclerosis and NAFLD. In both diseases, ncRNAs can exert pro-oxidant or antioxidant functions by regulating gene targets and even other ncRNAs, positioning them as potential therapeutic targets. Interestingly, both diseases have common altered ncRNAs, suggesting that the same molecule can be targeted simultaneously when both diseases coexist. Finally, since some ncRNAs have already been used as therapeutic agents, their roles as potential drugs for the clinical management of atherosclerosis and NAFLD are analyzed.

The effect of 12 weeks of combined training on hepatic fat content and metabolic flexibility of individuals with non-alcoholic fatty liver disease: Protocol of an open-label, single-center randomized control trial.

Metabolic flexibility (MetF) is the capacity of an organism to oxidate substrate according to substrate availability or demand. The mismatch of substrate availability and oxidation may cause ectopic fat accumulation in the muscle and the liver. The objectives of the study are to examine the effect of 12 weeks of combined exercise on hepatic fat reduction and investigate metabolites related to MetF before and after the high-fat diet between individuals with NAFLD and healthy control with an active lifestyle. This study is an open-label, single-center trial randomized controlled clinical study plus a cross-sectional comparison between individuals with NAFLD and healthy control. Individuals with NAFLD were allocated into two groups receiving resistance training (RT) combined with high-intensity interval training (HIIT) or moderate-intensity continuous training (MICT). Anthropometric indicators, clinical blood markers about glucose, lipid metabolism, and hepatic fat content (HFC) were assessed before and after the intervention. The metabolomics was also used to investigate the discrepant metabolites and mechanisms related to MetF. Metabolic flexibility reflects the capacity of an organism to switch the oxidation substrates flexibly, which is associated with ectopic fat accumulation. Our study aimed to explore the discrepant metabolites related to MetF before and after a high-fat diet between individuals with NAFLD and healthy control. In addition, the study also examined the effectiveness of RT combined with HIIT or MICT on hepatic fat reduction and quantificationally analyzed the metabolites related to MetF before and after the intervention. Our results provided a perspective on fatty liver-associated metabolic inactivity. ClinicalTrials.gov: ChiCTR2200055110; Registered 31 December 2021, http://www.chictr.org.cn/index.aspx.

PS-B08-7: L-CARNITINE AMELIORATES DIABETIC KIDNEY DISEASE BY ALLEVIATING MITOCHONDRIAL ABNORMALITY IN SDT-FATTY RATS

Background and Aims: Abnormal fatty acid metabolism is associated with the progression of diabetic kidney disease (DKD). Carnitine plays a central role in β;-oxidation and energy production by transporting long-chain fatty acids from the cytoplasm to the mitochondria. Recently, we found that significant ectopic fat was accumulated in the kidney tissue in DKD patients compared with those in minimal change kidney disease patients. Juvenile visceral steatosis (jvs) mice, described as an animal model for systemic carnitine deficiency, introduce a marked ectopic fat accumulation in the kidney. These findings suggest that abnormal carnitine dynamics in DKD cause ectopic fat accumulation due to abnormality of the fatty acid metabolism. However, the association between abnormalities of carnitine metabolism and the progression of DKD is unknown. Method: Spontaneously Diabetic Torii (SDT) fatty rat, an obese type 2 diabetic model was used. Unilateral nephrectomy was performed and 0.3% salt water was administered at 6 weeks of age, and created a renal dysfunction model in SDT fatty rat (DKD model). Age-matched male Sprague-Dawley (SD) rat was used as a control. Experiment 1: We compared 3 groups; SD rats (n = 8), SDT fatty rats (n = 8), DKD rats (n = 8). Experiment 2: We compared 3 groups; SD rats with sham operation (n = 8), DKD rats (n = 7), DKD rats treated with L-carnitine administration (0.75% L-carnitine diet) for 10 weeks (n = 6). All rats were sacrificed at 17 weeks old. Carnitine was measured by the enzyme cycling method. Acylcarnitine was analyzed by the tandem-mass spectrometry. Results: Plasma and renal free carnitine levels and short/middle-long chain acylcarnitine ratio were significantly decreased in DKD rats compared with those in SD and SDT fatty rats. The renal expression levels of organic cation / carnitine transporter 2 (OCTN2), carnitine palmitoyl transferase 1a (CPT1a), CPT2 and carnitine acetyltransferase (CrAT) were significantly decreased in DKD rats compared with those in SD and SDT fatty rats. Similarly, peroxisome proliferator-activated receptor γ co-activator 1α (PGC1α) activity was decreased in DKD rats. L-carnitine administration significantly improved renal function, urinary albumin excretion, interstitial fibrosis and renal ectopic fat accumulation in DKD model rats. L-carnitine administration ameliorated the decrease of renal OCTN2, CPT1a, CPT2 and CrAT protein expression, and significantly improved PGC1α activity in DKD model rats. Furthermore, L-carnitine administration mitigated lipid peroxidation and mitochondrial dysfunction in DKD rats. Conclusion: L-carnitine administration might be a promising therapeutic strategy for improving renal function by alleviating mitochondrial dysfunction in DKD rat model.

S-17-2: CLUSTER ANALYSIS OF DIABETES AND HYPERTENSION

Diabetes mellitus is classified into type 1 diabetes mellitus (T1DM) and type 2 diabetes mellitus (T2DM) according to etiology. T1DM occurs due to autoimmune β-cell destruction, usually leading to absolute insulin deficiency, whereas T2DM occurs due to a heterogenous combination of a relative insulin deficiency and insulin resistance. A data-driven cluster analysis reported five exclusive subgroups for diabetes: cluster 1 (severe autoimmune diabetes [SAID]), cluster 2 (severe insulin-deficient diabetes [SIDD]), cluster 3 (severe insulin-resistant diabetes [SIRD]), cluster 4 (mild obesity-related diabetes [MOD]), and cluster 5 (mild age-related diabetes [MARD]) (Ahlqvist et al, 2018). The subgroups have an advantage over the other classification because it uses simple but pathophysiologically feasible factors and is proven to apply to ethnic and racial differences to estimate diabetic complications (Diabetes Res Clin Pract 2021:180;109067). The SIRD cluster shows obesity and moderate to severe insulin resistance with hyperinsulinemia. Under severe metabolic deterioration based on insulin resistance through ectopic fat accumulation, individuals with SIRD are at high risk of developing atherosclerotic cardiovascular disease (ASCVD). SIRD confers the highest risk of developing diabetic kidney disease (DKD), commonly in Caucasians [Ahlqvist et al., 2018)] and non-Caucasians [Tanabe, 2020]. I will discuss the possible connection between cluster-derived diabetes subgroups and hypertension-associated complications.

Deletion or inhibition of PTPRO prevents ectopic fat accumulation and induces healthy obesity with markedly reduced systemic inflammation

AimsChronic inflammation plays crucial roles in obesity-induced metabolic diseases. Protein tyrosine phosphatase receptor type O (PTPRO) is a member of the R3 subfamily of receptor-like protein tyrosine phosphatases. We previously suggested a role for PTPRO in the inactivation of the insulin receptor. The present study aimed to elucidate the involvement of PTPRO in the control of glucose and lipid metabolism as well as in obesity-induced systemic inflammation. Materials and methodsLipid accumulation in adipose tissue and the liver, the expression of inflammatory cytokines, and insulin resistance associated with systemic inflammation were investigated in hyper-obese Ptpro-KO mice by feeding a high-fat/high-sucrose diet (HFHSD). The effects of the administration of AKB9778, a specific inhibitor of PTPRO, to ob/ob mice and cultured 3T3-L1 preadipocyte cells were also examined. Key findingsPtpro was highly expressed in visceral white adipose tissue and macrophages. Ptpro-KO mice fed HFHSD were hyper-obese, but did not have ectopic fat accumulation in the liver, dysfunctional lipid and glucose homeostasis, systemic inflammation, or insulin resistance. The administration of AKB9778 reproduced “the healthy obese phenotypes” of Ptpro-KO mice in highly obese ob/ob mice. Furthermore, the inhibition of PTPRO promoted the growth of lipid droplets in adipocytes through an increase in the phosphorylation of Tyr(117) in vimentin. SignificanceHealthy systemic conditions with the attenuation of inflammation in hyper-obese Ptpro-KO mice were associated with the expansion of adipose tissue and low activation of NF-κb. Therefore, PTPRO may be a promising target to ameliorate hepatic steatosis and metabolic dysfunction.

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

To investigate the distribution of abdominal fat, particularly ectopic fat accumulation, in relation to glucose metabolism in overweight/obese patients. 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. 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. Compared with visceral and pancreatic fat content, LFC is a superior risk biomarker for IGR in overweight/obese subjects.

Fatty Pancreas and Cardiometabolic Risk: Response of Ectopic Fat to Lifestyle and Surgical Interventions.

Ectopic fat accumulation in non-adipose organs, such as the pancreas and liver, is associated with an increased risk of cardiometabolic disease. While clinical trials have focused on interventions to decrease body weight and liver fat, ameliorating pancreatic fat can be crucial but successful intervention strategies are not yet defined. We identified twenty-two published studies which quantified pancreatic fat during dietary, physical activity, and/or bariatric surgery interventions targeted at body weight and adipose mass loss alongside their subsequent effect on metabolic outcomes. Thirteen studies reported a significant decrease in body weight, utilising weight-loss diets (n = 2), very low-energy diets (VLED) (n = 2), isocaloric diets (n = 1), a combination of diet and physical activity (n = 2), and bariatric surgery (n = 5) including a comparison with VLED (n = 1). Surgical intervention achieved the largest decrease in pancreatic fat (range: -18.2% to -67.2%) vs. a combination of weight-loss diets, isocaloric diets, and/or VLED (range: -10.2% to -42.3%) vs. diet and physical activity combined (range: -0.6% to -3.9%), with a concurrent decrease in metabolic outcomes. While surgical intervention purportedly is the most effective strategy to decrease pancreas fat content and improve cardiometabolic health, the procedure is invasive and may not be accessible to most individuals. Given that dietary intervention is the cornerstone for the prevention of adverse metabolic health, the alternative approaches appear to be the use of weight-loss diets or VLED meal replacements, which are shown to decrease pancreatic fat and associated cardiometabolic risk.

Serum CC-Chemokine Ligand 2 Is Associated with Visceral Adiposity but Not Fibrosis in Patients with Non-Alcoholic Fatty Liver Disease

Background: Non-alcoholic fatty liver disease (NAFLD) is caused by ectopic fat accumulation in the liver as a consequence of metabolic perturbations associated with obesity, type 2 diabetes, dyslipidemia, and insulin resistance. People with NAFLD may develop metabolic and cardiovascular complications and/or liver-related complications, especially fibrosis and hepatocellular carcinoma, associated with high morbidity and mortality. Due to the high and increasing prevalence of NAFLD, there is an urgent need to identify people at risk of developing liver fibrosis and complications. CC-chemokine ligand 2 (CCL2) is chemokine that attracts inflammatory monocytes to stressed or injured tissues. Infiltrating inflammatory monocytes and CCL2 are strongly implicated in the pathogenesis of liver disease in animal models; however, evidence in patient cohorts is conflicting. Methods: We investigated associations between circulating CCL2 and clinical parameters, including fibrosis assessed by liver stiffness measurement, in a cohort of 250 NAFLD patients. We also measured fatty acid binding protein 2 (FABP2), a putative biomarker of intestinal permeability in patients with liver disease, since pro-inflammatory gut-derived microbial products may induce inflammatory chemokines such as CCL2. Results: Serum CCL2 levels were weakly associated with liver stiffness, but the association was no longer significant after accounting for age, diabetes, and BMI in a multivariable model. Consistent with this, girth and BMI were the strongest predictors of elevated circulating CCL2. Serum FABP2 was weakly, but significantly, correlated with CCL2, and negatively correlated with estimated glomerular filtration rate. Conclusion: Circulating CCL2 and FABP2 are associated with NAFLD comorbidities but not liver disease progression in patients with NAFLD.

ODP011 Single Nuclei RNA-Sequencing of Frozen Human Adipose Tissue and PET/CT Imaging Coupled With Deep-Learning Reveals Single-Cell Landscape and Transcriptional Dynamics Related to Adipocyte Hypertrophy and in Vivo Dysmetabolism

Abstract Background Adipocyte hypertrophy is associated with glucose and lipid dysmetabolism, ectopic fat accumulation, and metabolic complications independently of the level of obesity [1]. In this study, we aimed to explore potential mechanisms driving the obesity-independent, hypertrophy-associated dysmetabolism at a single-cell resolution and to assess the applicability of single nuclei RNA-sequencing of flash-frozen human subcutaneous adipose tissue (AT) to probe for these metabolic differences. Methods In 40 healthy participants, peri-umbilical subcutaneous adipose tissue biopsies were collected by needle aspiration to determine adipocyte size. Tissue uptake of dietary fat was quantified via oral 18-fluoro-thiaheptadecanoic acid administration with positron emission tomography (PET) [2]. Rates of fatty acid oxidation and esterification were measured using intravenous [11C]-palmitate with PET and multi-compartmental modeling. PET/CT segmentation using deep convolutional neural networks was done with DeepImageTranslator [3,4]. Single nuclei RNA-sequencing was performed in two individuals with AT hypertrophy vs. hyperplasia but matched for the same sex, ethnicity, glucose-tolerance status, BMI, total and percent body fat, and waist circumference. Nuclei were extracted from frozen AT and purified by flow cytometry following a protocol that we have developed and validated. Capture of single nuclei and preparation of RNA libraries were done with 10X Genomics technology. Results Unsupervised clustering identified a number of cell-type markers identical to those previously reported in murine epididymal AT and human AT. We found reduced quantities of fibroadipogenic cells per volume of AT with fat cell hypertrophy. Furthermore, the fraction of DPP4+ fibroblasts is increased with AT hypertrophy. Analyses of RNA velocity shows decreased velocity of adipocyte transformation from a transcriptionally active (TADA) phenotype to mature adipocytes in AT hypertrophy. Furthermore, in AT hypertrophy, adipocytes from the early TADA stage are destined to become insulin-resistant adipocytes, whereas those in AT hyperplasia are developing into an insulin-sensitive phenotype. Metabolic imaging results show that hypertrophied subcutaneous AT is associated with lower subcutaneous and higher visceral AT volume and dietary fatty acid storage capacity. Conclusion We have documented, for the first time, the applicability and consistency of single-nuclei RNA-sequencing of frozen human subcutaneous AT. We uncovered changes in cell clusters and subclusters of adipocytes, fibroblasts, pericytes, endothelial and immune cells as well as differences in transcriptional dynamics and developmental trajectory. [1] Ye RZ, et al. Endocrine reviews. 2022 Feb;43(1): 35-60. [2] Montastier É, Ye RZ, et al. American Journal of Physiology-Endocrinology and Metabolism. 2021 Jun 1;320(6): E1093-106. [3] R. Z. Ye, et al., DeepImageTranslator: A free, user-friendly graphical interface for image translation using deep-learning and its applications in 3D CT image analysis, SLAS Technology, https://doi.org/10.1016/j.slast.2021.10. 014, [4] Ye EZ, Ye EH, Ye RZ. DeepImageTranslator V2: analysis of multimodal medical images using semantic segmentation maps generated through deep learning. bioRxiv. 2021 Jan 1. Presentation: No date and time listed

ODP424 Postprandial Adipose Insulin Resistance in Adolescent Girls with PCOS and Obesity

Abstract Background Polycystic ovary syndrome (PCOS) is common and associated with metabolic disease, in particular glucose abnormalities and insulin resistance (IR). Fat metabolism is linked with IR, manifesting as decreased suppression of lipolysis following meals, inflammation, and ectopic fat accumulation. Our previous work demonstrated adipose IR during a hyperinsulinemic-euglycemic clamp and increased hepatic fat in adolescents with PCOS. We hypothesized that postprandial fat metabolism would be altered compared to controls with obesity. Design/Methodology Data from 133 girls aged 13-21 years with obesity (BMI >90th%ile) enrolled in 1 of 4 cross-sectional metabolic studies were included in this secondary analysis. PCOS was determined per NIH diagnostic standards. Controls had regular menses and were >1-year post-menarche. Metabolic assessments were identical across studies and included fasting labs (lipid panel, inflammatory markers, androgens, insulin sensitivity indices), 4-hour oral sugar tolerance test (OSTT, 75 grams glucose, 25 grams fructose), liver fat by MRI, and body composition by DXA. Glycerol production (Ra) D5 glycerol infusion to measure lipolysis was evaluated in a subset. Metrics of glucose, insulin, glycerol, free fatty acid (FFA), and glucagon during the OSTT were calculated including AUC, fasting, nadir, and peak. Adipo IR (fasting FAA x fasting insulin) was determined. Data between controls and girls with PCOS were compared by Student's t-tests with Welch correction. Spearman's correlations were used within groups to evaluate associations. Results Participants included 110 girls with PCOS (age 16.4±1.6 years; BMI 35.9±5.8 kg/m2) and 23 without PCOS (15.9±1.6; 34.6±6.7). Per design, markers of androgen excess including total testosterone (p<0.001), free testosterone (p<0.001), degree of hirsutism (p=0.004), and severity of acne (p<0.001) were worse in girls with PCOS. Consistent with previous work, girls with PCOS had worse markers of glycemia including higher HbA1c (p<0.001), fasting glucose (p=0.027), 2-hour glucose (p=0.008), glucose AUC (p=0.033), and insulin AUC (p=0.034). They also had higher liver (p<0.001) and visceral fat (p=0.007), total (p=0.007) and LDL cholesterol (p=0.006), and triglycerides (p=0.005). Regarding adipose IR, fasting FFA (699±175 µmol/L vs. 593±163, p=0.007), FFA nadir (68±26 vs. 51±16, p=0.003), FFA AUC (114210 vs. 92518, p = 0.018), glycerol AUC (13815 vs. 8393, p<0.0001), and Adipo IR (p=0.034) were significantly higher while fasting glycerol Ra (p=0.571) did not differ. There were no differences between groups in markers of inflammation. Within the PCOS group, higher glycerol AUC correlated with higher HbA1c (p=0.001) and highly-sensitive C-reactive protein (hsCRP) (p=0.029), while increased FFA AUC correlated with increased hsCRP (p=0.043) and AST (p=0.037), but not markers of insulin resistance or dysglycemia. Conclusions Adolescents with PCOS and obesity have increased adipose IR. Future focus and treatment of adipose IR may be a promising avenue to delay onset of metabolic syndrome complications in girls with PCOS and obesity. Presentation: Monday, June 13, 2022 12:30 p.m. - 2:30 p.m.

OR23-1 FXR Regulates the Expansion and Metabolic Function of Adipose Tissue upon Caloric Excess

Abstract Obesity is a major risk factor for developing metabolic diseases. Adipose tissue stores excess calories during obesity. Nuclear receptor Farnesoid X receptor (FXR) is expressed in various tissues and transcriptionally regulates lipid and glucose metabolism. However, the role of FXR in regulating adipose expansion is unknown. We showed that Fxr transcript is expressed in mature adipocytes isolated from both white (WAT) and brown (BAT) adipose tissues. In adipocyte-specific Fxr knockout (Ad-FxrKO) mice, we found enlarged adipocytes and decreased expression of lipolytic genes upon 60% high fat diet (HFD) or high fat/high sucrose western diet challenge. Transcriptomic analysis of WAT from Ad-FxrKO and control mice upon chow or HFD revealed that many genes involved in glucose and lipid homeostasis are misregulated in Ad-FxrKO mice with distinct patterns under normal and obese conditions. Since WAT stores fat and BAT generates heat, we examined both these depots in Ad-FxrKO mice and found reductions in the expression of mitochondrial genes and energy expenditure. Intriguingly, we found ectopic fat accumulation in the liver and systemic glucose intolerance in Ad-FxrKO compared to the control mice during obesity. Overall, these findings implicate that FXR may regulate lipid metabolism and mitochondrial functions in the adipose tissue, which consequently impacts whole-body energy homeostasis. Presentation: Monday, June 13, 2022 11:15 a.m. - 11:30 a.m.

ODP426 SPIOMET4HEALTH: a 4-Arm Trial to Test the Effects of Lifestyle Intervention plus either Placebo, or Pioglitazone (PIO), or Spironolactone-Pioglitazone (SPIO), or Spironolactone-Pioglitazone-Metformin (SPIOMET) in Adolescent Girls and Young Women with PCOS

Abstract Introduction PCOS in adolescent girls and young women is nowadays thought to be, in essence, an epiphenomenon of ectopic fat accumulation. By definition, "adolescent PCOS" is characterized by androgen excess (as well clinical as biochemical) and oligo-anovulation (often judged by oligo-amenorrhea) (1) presenting between 2 and 8 years after menarche. There is no FDA-approved treatment for "adolescent PCOS". In SPIOMET4HEALTH (a project funded by the European Commission under Grant Agreement 899671), we aim at reducing ectopic fat in an early phase of PCOS, with a standardized lifestyle intervention plus a pharmacological addendum consisting of either placebo, or PIO, or SPIO, or SPIOMET. In "adolescent PCOS", low-dose pioglitazone (7.5 mg/d) may exert insulin-sensitizing and gonadotropin-normalizing effects, in part by raising the circulating concentrations of high-molecular-weight adiponectin; low-dose spironolactone (50 mg/d) may not only act as an anti-androgen but also exert anti-mineralocorticoid effects that raise energy expenditure by activating brown adipose tissue; low-dose metformin (850 mg/d) is known to act through multiple mechanisms and was recently shown to be capable of changing the relative deficit of GDF15 into an abundance that is thought to contribute to reduce liver fat. Subjects & Methods In the SPIOMET4HEALTH trial, patients with "adolescent PCOS" (age range 12. 0–23.9 years; BMI <35 kg/m 2) will be recruited in seven centers across Europe. A total of 364 patients are expected to engage into a lifestyle intervention, and to receive either placebo, or PIO, or SPIO, or SPIOMET once daily (1: 1: 1: 1 randomization; single tablets; double blinding) for 12 months. Post-treatment follow-up will span 6 months. The primary endpoint is ovulation rate, as judged by a combination of menstrual data and progesterone concentrations in saliva; the analysis will start by testing for superiority between placebo and SPIOMET. Secondary endpoints include pre-treatment, on-treatment and post-treatment measures of androgen excess, body composition and insulin sensitivity, as well as measures of quality of life, and of adherence to treatment. The design of this trial has been endorsed by the European Medicines Agency, as part of a "Paediatric Investigation Plan". Expected Results/Discussion The SPIOMET4HEALTH project is expected to deliver the first results of an international, randomized, double-blind, active-controlled/placebo-controlled trial evaluating the safety, efficacy, and tolerability of the fixed dose combination SPIOMET in adolescent girls and young women with PCOS. Favorable results of this Phase 2 trial may advance SPIOMET into Phase 3. Reference: Ibáñez L, et al. An International Consortium Update: pathophysiology, diagnosis, and treatment of polycystic ovarian syndrome in adolescence. Horm Res Paediatr 2017;88: 371-395. Presentation: No date and time listed