Ectopic fat in insulin resistance, dyslipidemia, and cardiometabolic disease

Ethnic differences in the relationship between ectopic fat deposition and insulin sensitivity in Black African and White European men across a spectrum of glucose tolerance

AIM

To examine the hypothesis that there would be ethnic differences in the relationship between ectopic fat and tissue-specific insulin resistance (IR) across a spectrum of glucose tolerance in Black African (BA) and White European (WE) men.

MATERIALS AND METHODS

Fifty-three WE men (23/10/20 normal glucose tolerance [NGT]/impaired glucose tolerance [IGT]/type 2 diabetes [T2D]) and 48 BA men (20/10/18, respectively) underwent a two-step hyperinsulinaemic-euglycaemic clamp with infusion of D-[6,6-2H2]-glucose and [2H5]-glycerol to assess hepatic, peripheral and adipose tissue IR. Magnetic resonance imaging was used to measure subcutaneous adipose tissue, visceral adipose tissue (VAT) and intrahepatic lipid (IHL). Associations between ectopic fat and IR were assessed using linear regression models.

RESULTS

There were no differences in tissue-specific IR between ethnic groups at any stage of glucose tolerance. VAT level was consistently lower in the BA population; NGT (p = 0.013), IGT (p = 0.006) and T2D (p = 0.015). IHL was also lower in the BA compared with the WE men (p = 0.013). VAT and IHL levels were significantly associated with hepatic IR in the BA population (p = 0.001) and with peripheral IR in the WE population (p = 0.027).

CONCLUSIONS

The present study suggests that BA and WE men exhibit the same degree of IR across a glucose tolerance continuum, but with lower VAT and IHL levels in the BA population, suggesting that IR may be driven by a mechanism other than increased ectopic fat accumulation in BA men.

A 3-Week Ketogenic Diet Increases Skeletal Muscle Insulin Sensitivity in Individuals With Obesity: A Randomized Controlled Crossover Trial

A ketogenic diet (KD) can induce weight loss and improve glycemic regulation, potentially reducing the risk of type 2 diabetes development. To elucidate the underlying mechanisms behind these beneficial effects of a KD, we investigated the impact of a KD on organ-specific insulin sensitivity (IS) in skeletal muscle, liver, and adipose tissue. We hypothesized that a KD would increase IS in skeletal muscle. The study included 11 individuals with obesity who underwent a randomized, crossover trial with two 3-week interventions: 1) a KD and 2) a standard diet. Skeletal muscle IS was quantified as the increase in glucose disposal during a hyperinsulinemic-euglycemic clamp (HEC). Hepatic IS and adipose tissue IS were quantified as the relative suppression of endogenous glucose production (EGP) and the relative suppression of palmitate flux during the HEC. The KD led to a 2.2-kg weight loss and increased insulin-stimulated glucose disposal, whereas the relative suppression of EGP during the HEC was similar. In addition, the KD decreased insulin-mediated suppression of lipolysis. In conclusion, a KD increased skeletal muscle IS in individuals with obesity.

ARTICLE HIGHLIGHTS

The Herbal Blend of Sphaeranthus indicus and Garcinia mangostana Reduces Adiposity in High-Fat Diet Obese Mice

Obesity is swiftly becoming a global epidemic, leading to numerous metabolic disorders and substantial socio-economic burdens. Investigating natural bioactive compounds is crucial to support the use of traditional anti-obesity medications while mitigating the adverse effects. This study posited that a combination of Sphaeranthus indicus and Garcinia mangostana (Meratrim) could prevent fat accumulation in obese mice. We used 4-week-old C57BL/6NTac mice, dividing them into six groups: (1) normal diet (ND); (2) high-fat diet (HFD, 45% kcal from fat); (3-5) Meratrim150, Meratrim300, and Meratrim450 (HFD with 150, 300, and 450 mg/kg bw of Meratrim); and (6) Metformin (HFD with 150 mg/kg bw of metformin). Meratrim was administered orally each day for 20 weeks. The group receiving 450 mg/kg of Meratrim showed a significant reduction in body weight and fat mass without changes in food consumption. The Meratrim450 group had markedly lower triglyceride levels in both serum and liver. Importantly, Meratrim-supplemented mice improved lipid homeostasis by inhibiting hepatic de novo lipogenesis and activating energy catabolic pathways such as non-shivering thermogenesis in brown adipose tissue. Our results suggest that the herbal mixture of Sphaeranthus indicus and Garcinia mangostana (Meratrim) is a promising natural anti-obesity agent, owing to its efficacy in reducing body fat and enhancing lipid homeostasis.

Ceramide synthesis inhibitors prevent lipid-induced insulin resistance through the DAG-PKCε-insulin receptorT1150 phosphorylation pathway

Inhibition of the ceramide synthetic pathway with myriocin or an antisense oligonucleotide (ASO) targeting dihydroceramide desaturase (DES1) both improved hepatic insulin sensitivity in rats fed either a saturated or unsaturated fat diet and was associated with reductions in both hepatic ceramide and plasma membrane (PM)-sn-1,2-diacylglycerol (DAG) content. The insulin sensitizing effects of myriocin and Des1 ASO were abrogated by acute treatment with an ASO against DGAT2, which increased hepatic PM-sn-1,2-DAG but not hepatic C16 ceramide content. Increased PM-sn-1,2-DAG content was associated with protein kinase C (PKC)ε activation, increased insulin receptor (INSR)T1150 phosphorylation leading to reduced insulin-stimulated INSRY1152/AktS473 phosphorylation, and impaired insulin-mediated suppression of endogenous glucose production. These results demonstrate that inhibition of de novo ceramide synthesis by either myriocin treatment or DES1 knockdown protects against lipid-induced hepatic insulin resistance through a C16 ceramide-independent mechanism and that they mediate their effects to protect from lipid-induced hepatic insulin resistance via the PM-sn-1,2-DAG-PKCε-INSRT1150 phosphorylation pathway.

Combined effects of vitamin D3 and dioxopiperidinamide derivative on lipid homeostasis, inflammatory pathways, and redox imbalance in non-alcoholic fatty liver disease in vivo zebrafish model

Liver damage and metabolic dysfunctions, the defining features of non-alcoholic fatty liver disease (NAFLD), are marked by inflammation, oxidative stress, and excessive hepatic fat accumulation. The current therapeutic approaches for NAFLD are limited, necessitating exploring novel treatment strategies. Dioxopiperidinamide derivatives, particularly DOPA-33, have shown effective anti-inflammatory and antioxidant properties, potentially offering therapeutic benefits against NAFLD. This study investigated the combined potential of vitamin D3 (Vit D3) and DOPA-33 in treating NAFLD. The network pharmacology analysis identified key NAFLD targets modulated by Vit D3 and DOPA-33, emphasizing their potential mechanisms of action. In NAFLD-induced zebrafish models, Vit D3 and DOPA-33 significantly reduced hepatic lipid accumulation, oxidative stress, and apoptosis, demonstrating superior efficacy over individual treatments. The treatment also lowered reactive oxygen species (ROS) levels, decreased liver damage, and enhanced antioxidant defense mechanisms. Moreover, behavioral analyses showed improved locomotion and reduced weight gain in treated zebrafish. Biochemical analyses revealed lower triglycerides (TG) and glucose levels with improved oxidative markers. Furthermore, histological analyses indicated reduced hepatic steatosis and inflammation, with decreased expression of lipogenesis-related genes and inflammatory mediators. Finally, high-performance liquid chromatography (HPLC) confirmed a significant reduction in hepatic cholesterol levels, indicating the effectiveness of the combination therapy in addressing key NAFLD-related dyslipidemias. These findings suggest that Vit D3 + DOPA-33 targets pathways involved in lipid metabolism, inflammation, and oxidative stress by offering a promising therapeutic approach for NAFLD.

Sex- and gender-based medicine in pediatric nutrition

Consistent evidence increasingly highlights the significance of integrating sex and gender medicine to ensure a precision approach according to individual patient needs. Gender discrepancies emerge across various areas, even from pediatric age. The importance of recognizing these differences in pediatric nutrition is critical for the development of targeted nutritional strategies and interventions, particularly in cases of associated pathologies, including obesity, metabolic-associated fatty liver disease, eating disorders, and inflammatory bowel disease. The review highlights the biological and sociocultural factors that contribute to different nutritional needs and health outcomes in male and female children. By examining current evidence, we underscore the necessity for precision medicine approaches in pediatric care that consider these sex- and gender-based differences. Moreover, differences in dietary requirements and dietary patterns between males and females are evident, underscoring the need for precise nutrition strategies for a more accurate management of children and adolescents. This approach is essential for improving clinical outcomes and promoting equitable healthcare practices. This review aims to provide an overview of nutrition-related medical conditions exhibiting sex- and gender-specific discrepancies, which might lead to distinct outcomes requiring unique management and prevention strategies. Future research and public health initiatives should address these differences in designing effective lifestyle education programs and nutrition interventions targeting both children and adolescents.

Early onset type 2 diabetes mellitus: an update

The incidence and prevalence of type 2 diabetes mellitus (T2DM) in young individuals (aged <40 years) have significantly increased in recent years, approximating two to threefold increase in the respective rates. Numerous risk factors including severe obesity, family history, ethnicity, maternal diabetes or gestational diabetes, and female sex contribute to a younger age of onset. In terms of pathogenesis, impaired insulin secretion is the key operating mechanism, alongside with ectopic adiposity-related insulin resistance. T2DM diagnosis in a young adult requires the exclusion of type 1 diabetes mellitus (T1DM), latent autoimmune diabetes of adults (LADA) and maturity-onset diabetes of the young (MODY). The establishment of such diagnosis is critical for prognosis, because early-onset T2DM is associated with rapid deterioration in pancreatic β-cell secretory function leading to earlier initiation of insulin therapy. Furthermore, mortality and lifetime risk of developing complications, especially microvascular, is increased in these patients compared to both later-onset T2DM and T1DM patients; also, the latter are often developed earlier in the course of disease. The management of early-onset T2DM follows the same guidelines as in later-onset T2DM; yet patients aged 18-39 years are underrepresented in the big clinical trials on which the development of guidelines is based. Finally, young people with T2DM face significant challenges associated with social determinants, which compromise their adherence to therapy and induce diabetes distress. Future research focusing on the pathogenesis of β-cell decline and complications, as well as on specific treatment shall lead to better understanding and management of early-onset T2DM.

Bruton's tyrosine kinase (BTK) inhibitors alter blood glucose and insulin in obese mice but reduce inflammation independent of BTK

Obesity is associated with metabolic inflammation, which can contribute to insulin resistance, higher blood glucose, and higher insulin indicative of prediabetes progression. The nucleotide-binding oligomerization domain-like receptor family pyrin domain containing 3 (NLRP3) inflammasome is a metabolic danger sensor implicated in metabolic inflammation. Many features of metabolic disease can activate the NLRP3 inflammasome; however, it is not yet clear which upstream triggers to target, and there are no clinically approved NLRP3 inflammasome inhibitors for metabolic disease. Bruton's tyrosine kinase (BTK) mediates activation of the NLRP3 inflammasome. Ibrutinib is the most-studied pharmacological inhibitor of BTK, and it can improve blood glucose control in obese mice. However, inhibitors of tyrosine kinases are permissive, and it is unknown if BTK inhibitors require BTK to alter endocrine control of metabolism or metabolic inflammation. We tested whether ibrutinib and acalabrutinib, a new generation BTK inhibitor with higher selectivity, require BTK to inhibit the NLRP3 inflammasome, metabolic inflammation, and blood glucose in obese mice. Chronic ibrutinib administration lowered fasting blood glucose and improved glycemia, whereas acalabrutinib increased fasting insulin levels and increased markers of insulin resistance in high-fat diet-fed CBA/J mice with intact Btk. These metabolic effects of BTK inhibitors were absent in CBA/CaHN-Btkxid/J mice with mutant Btk. However, ibrutinib and acalabrutinib reduced NF-κB activity, proinflammatory gene expression, and NLRP3 inflammasome activation in macrophages with and without functional BTK. These data highlight that the BTK inhibitors can have divergent effects on metabolism and separate effects on metabolic inflammation that can occur independently of actions on BTK.NEW & NOTEWORTHY Bruton's tyrosine kinase (BTK) is involved in immune function. It was thought that BTK inhibitors improve characteristics of obesity-related metabolic disease by lowering metabolic inflammation. However, tyrosine kinase inhibitors are permissive, and it was not known if different BTK inhibitors alter host metabolism or immunity through actions on BTK. We found that two BTK inhibitors had divergent effects on blood glucose and insulin via BTK, but inhibition of metabolic inflammation occurred independently of BTK in obese mice.

Relation Between Obesity and Type 2 Diabetes: Evolutionary Insights, Perspectives and Controversies

PURPOSE OF REVIEW

Since the mid-twentieth century, obesity and its related comorbidities, notably insulin resistance (IR) and type 2 diabetes (T2D), have surged. Nevertheless, their underlying mechanisms remain elusive. Evolutionary medicine (EM) sheds light on these issues by examining how evolutionary processes shape traits and diseases, offering insights for medical practice. This review summarizes the pathogenesis and genetics of obesity-related IR and T2D. Subsequently, delving into their evolutionary connections. Addressing limitations and proposing future research directions aims to enhance our understanding of these conditions, paving the way for improved treatments and prevention strategies.

RECENT FINDINGS

Several evolutionary hypotheses have been proposed to unmask the origin of obesity-related IR and T2D, e.g., the "thrifty genotype" hypothesis suggests that certain "thrifty genes" that helped hunter-gatherer populations efficiently store energy as fat during feast-famine cycles are now maladaptive in our modern obesogenic environment. The "drifty genotype" theory suggests that if thrifty genes were advantageous, they would have spread widely, but proposes genetic drift instead. The "behavioral switch" and "carnivore connection" hypotheses propose insulin resistance as an adaptation for a brain-dependent, low-carbohydrate lifestyle. The thrifty phenotype theory suggests various metabolic outcomes shaped by genes and environment during development. However, the majority of these hypotheses lack experimental validation. Understanding why ancestral advantages now predispose us to diseases may aid in drug development and prevention of disease. EM helps us to understand the evolutionary relation between obesity-related IR and T2D. But still gaps and contradictions persist. Further interdisciplinary research is required to elucidate complete mechanisms.

Sex-Specific Variation in Metabolic Responses to Diet

Suboptimal nutrition is a leading cause of cardiometabolic disease and mortality. Biological sex is a variable that influences individual responses to dietary components and may modulate the impact of diet on metabolic health and disease risk. This review describes findings of studies reporting how biological sex may associate with or affect metabolic outcomes or disease risk in response to varying dietary macronutrient content, Mediterranean diet, Western diet, and medical very low-calorie diet. Although few dietary interventions have been specifically designed to identify sex-diet interactions, future studies improving understanding how sex influences dietary responses could inform precision nutrition interventions for disease prevention and management.

Exercise as a tool to mitigate metabolic disease

Metabolic diseases, notably obesity and type 2 diabetes (T2D), have reached alarming proportions and constitute a significant global health challenge, emphasizing the urgent need for effective preventive and therapeutic strategies. In contrast, exercise training emerges as a potent intervention, exerting numerous positive effects on metabolic health through adaptations to the metabolic tissues. Here, we reviewed the major features of our current understanding with respect to the intricate interplay between metabolic diseases and key metabolic tissues, including adipose tissue, skeletal muscle, and liver, describing some of the main underlying mechanisms driving pathogenesis, as well as the role of exercise to combat and treat obesity and metabolic disease.

Dietary fats as regulators of neutrophil plasticity: an update on molecular mechanisms

PURPOSE OF REVIEW

Contemporary guidelines for the prevention of cardio-metabolic diseases focus on the control of dietary fat intake, because of their adverse metabolic effects. Moreover, fats alter innate immune defenses, by eliciting pro-inflammatory epigenetic mechanisms on the long-living hematopoietic cell progenitors which, in the bone marrow, mainly give rise to short-living neutrophils. Nevertheless, the heterogenicity of fats and the complexity of the biology of neutrophils pose challenges in the understanding on how this class of nutrients could contribute to the development of cardio-metabolic diseases via specific molecular mechanisms activating the inflammatory response.

RECENT FINDINGS

The knowledge on the biology of neutrophils is expanding and there are now different cellular networks orchestrating site-specific reprogramming of these cells to optimize the responses against pathogens. The innate immune competence of neutrophil is altered in response to high fat diet and contributes to the development of metabolic alterations, although the precise mechanisms are still poorly understood.

SUMMARY

Defining the different molecular mechanisms involved in the fat-neutrophil crosstalk will help to reconcile the sparse data about the interaction of dietary fats with neutrophils and to tailor strategies to target neutrophils in the context of cardio-metabolic diseases.

Adiposity modifies the association between heart failure risk and glucose metabolic disorder in older individuals: a community-based prospective cohort study

BACKGROUND

Glucose metabolic disorder is associated with the risk of heart failure (HF). Adiposity is a comorbidity that is inextricably linked with abnormal glucose metabolism in older individuals. However, the effect of adiposity on the association between glucose metabolic disorder and HF risk, and the underlying mechanism remain unclear.

METHODS

A total of 13,251 participants aged ≥ 60 years from a cohort study were categorized into euglycemia, prediabetes, uncontrolled diabetes, and well-controlled diabetes. Adiposity was assessed using body mass index (BMI), waist-to-hip ratio (WHR), and visceral fat area (VFA). Adiposity-associated metabolic activities were evaluated using adiponectin-to-leptin ratio (ALR), homeostatic model assessment of insulin resistance (HOMA-IR), and triglyceride-glucose index (TyG). The first occurrence of HF served as the outcome during the follow-up period.

RESULTS

A total of 1,138 participants developed HF over the course of an average follow-up period of 10.9 years. The rate of incident HF occurrence was higher in prediabetes, uncontrolled diabetes, and well-controlled diabetes participants compared to that in euglycemia participants. However, the high rates were significantly attenuated by BMI, VFA, and WHR. For WHR in particular, the hazard ratio for incident HF was 1.18 (95% confidence interval (CI): 1.03, 1.35, Padj.=0.017) in prediabetes, 1.59 (95% CI: 1.34, 1.90, Padj.<0.001) in uncontrolled diabetes, and 1.10 (95% CI: 0.85, 1.43, Padj.=0.466) in well-controlled diabetes. The population attributable risk percentage for central obesity classified by WHR for incident HF was 30.3% in euglycemia, 50.0% in prediabetes, 48.5% in uncontrolled diabetes, and 54.4% in well-controlled diabetes. Adiposity measures, especially WHR, showed a significant interaction with glucose metabolic disorder in incident HF (all Padj.<0.001). ALR was negatively associated and HOMA-IR and TyG were positively associated with BMI, WHR, VFA, and incident HF (all Padj.<0.05). ALR, HOMA-IR, and TyG mediated the associations for BMI, WHR and VFA with incident HF (all Padj.<0.05).

CONCLUSIONS

Adiposity attenuated the association of glucose metabolic disorder with incident HF. The results also showed that WHR may be an appropriate indicator for evaluating adiposity in older individuals. Adiposity-associated metabolic activities may have a bridging role in the process of adiposity attenuating the association between glucose metabolic disorder and incident HF.

TRIAL REGISTRATION

retrospectively registered number: ChiCTR-EOC-17,013,598.

The additive effect of the triglyceride-glucose index and estimated glucose disposal rate on long-term mortality among individuals with and without diabetes: a population-based study

BACKGROUND

The triglyceride-glucose (TyG) index and estimated glucose disposal rate (eGDR), which are calculated using different parameters, are widely used as markers of insulin resistance and are associated with cardiovascular diseases and prognosis. However, whether they have an additive effect on the risk of mortality remains unclear. This study aimed to explore whether the combined assessment of the TyG index and eGDR improved the prediction of long-term mortality in individuals with and without diabetes.

METHODS

In this cross-sectional and cohort study, data were derived from the National Health and Nutrition Examination Survey (NHANES) 2001-2018, and death record information was obtained from the National Death Index. The associations of the TyG index and eGDR with all-cause and cardiovascular mortality were determined by multivariate Cox regression analysis and restricted cubic splines.

RESULTS

Among the 17,787 individuals included in the analysis, there were 1946 (10.9%) all-cause deaths and 649 (3.6%) cardiovascular deaths during a median follow-up of 8.92 years. In individuals with diabetes, the restricted cubic spline curves for the associations of the TyG index and eGDR with mortality followed a J-shape and an L-shape, respectively. The risk of mortality significantly increased after the TyG index was > 9.04 (all-cause mortality) or > 9.30 (cardiovascular mortality), and after eGDR was < 4 mg/kg/min (both all-cause and cardiovascular mortality). In individuals without diabetes, the association between eGDR and mortality followed a negative linear relationship. However, there was no association between the TyG index and mortality. Compared with individuals in the low TyG and high eGDR group, those in the high TyG and low eGDR group (TyG > 9.04 and eGDR < 4) showed the highest risk for all-cause mortality (hazard ratio [HR] = 1.592, 95% confidence interval [CI] 1.284-1.975) and cardiovascular mortality (HR = 1.683, 95% CI 1.179-2.400) in the overall population. Similar results were observed in individuals with and without diabetes.

CONCLUSIONS

There was a potential additive effect of the TyG index and eGDR on the risk of long-term mortality in individuals with and without diabetes, which provided additional information for prognostic prediction and contributed to improving risk stratification.

Diet and physical exercise as key players to tackle MASLD through improvement of insulin resistance and metabolic flexibility

Metabolic Dysfunction-Associated Steatotic Liver Disease (MASLD) has emerged as a prevalent health concern, encompassing a wide spectrum of liver-related disorders. Insulin resistance, a key pathophysiological feature of MASLD, can be effectively ameliorated through dietary interventions. The Mediterranean diet, rich in whole grains, fruits, vegetables, legumes, and healthy fats, has shown promising results in improving insulin sensitivity. Several components of the Mediterranean diet, such as monounsaturated fats and polyphenols, exert anti-inflammatory and antioxidant effects, thereby reducing hepatic steatosis and inflammation. Furthermore, this dietary pattern has been associated with a higher likelihood of achieving MASLD remission. In addition to dietary modifications, physical exercise, particularly resistance exercise, plays a crucial role in enhancing metabolic flexibility. Resistance exercise training promotes the utilization of fatty acids as an energy source. It enhances muscle glucose uptake and glycogen storage, thus reducing the burden on the liver to uptake excess blood glucose. Furthermore, resistance exercise stimulates muscle protein synthesis, contributing to an improved muscle-to-fat ratio and overall metabolic health. When implemented synergistically, the Mediterranean diet and resistance exercise can elicit complementary effects in combating MASLD. Combined interventions have demonstrated additive benefits, including greater improvements in insulin resistance, increased metabolic flexibility, and enhanced potential for MASLD remission. This underscores the importance of adopting a multifaceted approach encompassing dietary modifications and regular physical exercise to effectively manage MASLD. This narrative review explores the biological mechanisms of diet and physical exercise in addressing MASLD by targeting insulin resistance and decreased metabolic flexibility.

Novel insights into causal effects of maternal nonalcoholic fatty liver disease on adverse pregnancy outcomes: evidence from Human Genetics and Mendelian Randomization Study

BACKGROUND

Observational studies have associated nonalcoholic fatty liver disease (NAFLD) with adverse pregnancy events, but findings show heterogeneity, leaving the causal direction and mediating pathways unclear. We aimed to investigate the causal relation between NAFLD and various pregnancy events, and to elucidate the underlying mediating pathways while determining the proportion of this correlation that is mediated through these pathways.

METHODS

A genome-wide association study involving over 6 million participants employing Mendelian randomization (MR) and mediation analysis was performed. The study used genetically predicted NAFLD as exposures and cardiometabolic traits as mediators, with various adverse pregnancy events as outcomes. The main analysis was performed using the inverse variance weighted (IVW) approach, while sensitivity analyses included the weighted median, weighted mode, MR-Egger, and MR-PRESSO methods. Mediation analyses were performed using a two-step MR framework.

RESULTS

In this MR cohort study, NAFLD was found to be strongly associated with elevated risks of GDM (P = 0.019 for the discovery dataset, P < 0.001 for the discovery dataset) and HDPs, including any HDP (P < 0.001 for the both datasets), gestational hypertension (P = 0.007 for the discovery dataset, P < 0.001 for the discovery dataset), and pre-eclampsia or eclampsia (P = 0.040 for the discovery dataset, P < 0.001 for the discovery dataset). However, no significant associations were found with hemorrhage in early pregnancy, postpartum hemorrhage, preterm birth, or offspring birthweight for both datasets. Cardiometabolic traits played a significant mediating role in these associations, rather than solely acting as confounding factors.

CONCLUSIONS

This study provided evidence supporting a correlation between NAFLD and a higher risk of adverse pregnancy events and introduces some new insights. These findings may inform preventions and interventions for remediating adverse pregnancy outcomes attributable to NAFLD.

Aging human abdominal subcutaneous white adipose tissue at single cell resolution

White adipose tissue (WAT) is a robust energy storage and endocrine organ critical for maintaining metabolic health as we age. Our aim was to identify cell-specific transcriptional aberrations that occur in WAT with aging. We leveraged full-length snRNA-Seq and histology to characterize the cellular landscape of human abdominal subcutaneous WAT in a prospective cohort of 10 younger (≤30 years) and 10 older individuals (≥65 years) balanced for sex and body mass index (BMI). The older group had greater cholesterol, very-low-density lipoprotein, triglycerides, thyroid stimulating hormone, and aspartate transaminase compared to the younger group (p < 0.05). We highlight that aging WAT is associated with adipocyte hypertrophy, increased proportions of lipid-associated macrophages and mast cells, an upregulation of immune responses linked to fibrosis in pre-adipocyte, adipocyte, and vascular populations, and highlight CXCL14 as a biomarker of these processes. We show that older WAT has elevated levels of senescence marker p16 in adipocytes and identify the adipocyte subpopulation driving this senescence profile. We confirm that these transcriptional and phenotypical changes occur without overt fibrosis and in older individuals that have comparable WAT insulin sensitivity to the younger individuals.

Active Targets and Potential Mechanisms of Erhuang Quzhi Formula in Treating NAFLD: Network Analysis and Experimental Assessment

The purpose of this research was to investigate the main active components, potential targets of action, and pharmacological mechanisms of Erhuang Quzhi Formula (EHQZF) against NAFLD using network pharmacology, molecular docking, and experimental validation. The main active chemical components of EHQZF and the potential targets for treating NAFLD were extracted and analyzed. The PPI network diagram of "Traditional Chinese Medicine-Active Ingredients-Core Targets" was constructed and the GO, KEGG, and molecular docking analysis were carried out. Identification of components in traditional Chinese medicine compounds was conducted by LC-MS. NAFLD models were established and relevant pathologic indicators and Western blot were analyzed in vivo and ex vivo. Totally 8 herbs attributed to the liver meridian and 20 corresponding targets of NAFLD were obtained from EHQZF. Flavonoids and phenolic acids as the main components of EHQZF treated NAFLD through the MAPK/AKT signaling pathway. Pathway enrichment analysis focused on the MAPK/AKT signaling pathway and apoptosis signaling pathway. Molecular docking showed that Quercetin and Luteolin had stable binding structures with AKT1, STAT3, and other targets. Experiments showed that EHQZF reduced lipid accumulation, regulated changes in adipose tissue, inhibited the MAPK/AKT signaling pathway and exert multiple components, several targets, and multiple pathway interactions to treat NAFLD.

Multi-dimensional comparison of abdominal obesity indices and insulin resistance indicators for assessing NAFLD

BACKGROUND

The prevalence of non-alcoholic fatty liver disease (NAFLD) keeps increasing annually worldwide. Non-invasive assessment tools for evaluating the risk and severity of the disease are still limited. Insulin resistance (IR) and abdominal obesity (ABO) are closely related to NAFLD.

METHODS

A retrospective large-scale, population-based study was conducted based on the data from the 2017-2018 cycle of the National Health and Nutrition Examination Survey (NHANES). Three ABO indices, namely lipid accumulation product (LAP), visceral obesity index (VAI), waist circumference-triglyceride index (WTI), and three IR indices, including triglyceride glucose index (TyG), homeostasis model assessment of insulin resistance (HOMA-IR) and metabolic score for insulin resistance (METS-IR), were analyzed and compared for their relationships with NAFLD based on weighted multivariable logistic regression, spearman correlation heatmap, smooth curve fittings. The area under the curve (AUC) of receiver-operating characteristic (ROC) curve was used to evaluate the diagnostic capability of these indices for NAFLD. Differences among the AUCs were calculated and compared by Delong test.

RESULTS

In total, 3095 participants were included in our study among which 1368 adults were diagnosed with NAFLD. All six indices presented positive associations with NAFLD. There was a claw-shaped curve between HOMA-IR, VAI, LAP and NAFLD while a smooth semi-bell curve was observed in TyG, METS-IR and WTI. LAP and HOMA-IR had the best diagnostic capability for NAFLD (LAP: AUC = 0.8, Youden index = 0.48; HOMA-IR: AUC = 0.798, Youden index = 0.472) while VAI (AUC = 0.728, Youden index = 0.361) showed the lowest predictive value. The correlation heat map indicated positive correlations between all six indices and liver function, hepatic steatosis and fibrosis severity. In the NAFLD group, IR indicators presented a stronger association with alanine aminotransferase (ALT) compared with ABO indices.

CONCLUSIONS

All six indices can screen NAFLD withLAP and HOMA-IR being possibly optimal predictors. IR indices may be more sensitive to identify acute hepatic injury in NAFLD patients than ABO indices.

Association between atherogenic dyslipidemia and muscle quality defined by myosteatosis

Background

Myosteatosis, ectopic fat accumulation in skeletal muscle, is a crucial component of sarcopenia, linked to various cardiometabolic diseases. This study aimed to analyze the association between dyslipidemia and myosteatosis using abdominal computed tomography (CT) in a large population.

Methods

This study included 11,823 patients not taking lipid-lowering medications with abdominal CT taken between 2012 and 2013. Total abdominal muscle area (TAMA), measured at the L3 level, was segmented into skeletal muscle area (SMA) and intramuscular adipose tissue. SMA was further classified into normal attenuation muscle area (NAMA: good quality muscle) and low attenuation muscle area (poor quality muscle). NAMA divided by TAMA (NAMA/TAMA) represents good quality muscle. Atherosclerotic dyslipidemia was defined as high-density lipoprotein cholesterol (HDL-C) less than 40 mg/dL in men and 50 mg/dL in women, low-density lipoprotein cholesterol (LDL-C) greater than 160 mg/dL, triglycerides (TG) greater than 150 mg/dL, small dense LDL-C (sdLDL-C) greater than 50.0 mg/dL, or apolipoprotein B/A1 (apoB/A1) greater than 0.08.

Results

The adjusted odds ratios (ORs) of dyslipidemia according to the HDL-C and sdLDL definitions were greater in both sexes in the lower quartiles (Q1~3) of NAMA/TAMA compared with Q4. As per other definitions, the ORs were significantly increased in only women for LDL-C and only men for TG and ApoB/A1. In men, all lipid parameters were significantly associated with NAMA/TAMA, while TG and ApoB/A1 did not show significant association in women.

Conclusion

Myosteatosis measured in abdominal CT was significantly associated with a higher risk of dyslipidemia. Myosteatosis may be an important risk factor for dyslipidemia and ensuing cardiometabolic diseases.

Inflammation-associated intramyocellular lipid alterations in human pancreatic cancer cachexia

BACKGROUND

Cancer cachexia is a multifactorial metabolic syndrome characterized by systemic inflammation and ongoing skeletal muscle loss resulting in weakness, poor quality of life, and decreased survival. Whereas lipid accumulation in skeletal muscle is associated with cancer cachexia as well as the prognosis of cancer patients, surprisingly little is known about the nature of the lipids that accumulate in the muscle during cachexia, and whether this is related to inflammation. We aimed to identify the types and distributions of intramyocellular lipids in patients with and without cancer cachexia.

METHODS

Rectus abdominis muscle biopsies were collected during surgery of patients with pancreatic ductal adenocarcinoma (n = 10 without cachexia, n = 20 cachectic without inflammation (CRP < 10 mg/L), n = 10 cachectic with inflammation (CRP ≥ 10 mg/L). L3-CT scans were analysed to assess body composition based on validated thresholds in Hounsfield units (HU). Muscle sections were stained with Oil-Red O and H&E to assess general lipid accumulation and atrophy. Untargeted lipidomic analyses were performed on laser-microdissected myotubes using LC-MS/MS. The spatial distribution of intramyocellular lipids with differential abundance between groups was visualized by mass-spectrometry imaging. Genes coding for inflammation markers and enzymes involved in de novo ceramide synthesis were studied by qPCR.

RESULTS

Muscle radiation attenuation was lower in cachectic patients with inflammation (median 24.3 [18.6-30.8] HU) as compared with those without inflammation (34.2 [29.3-38.7] HU, P = 0.033) or no cachexia (37.4 [33.9-42.9] HU, P = 0.012). Accordingly, intramyocellular lipid content was lower in non-cachectic patients (1.9 [1.6-2.1]%) as compared with those with cachexia with inflammation (5.5 [4.5-7.3]%, P = 0.002) or without inflammation (4.8 [2.6-6.0]%, P = 0.017). Intramyocellular lipid accumulation was associated with both local IL-6 mRNA levels (rs = 0.57, P = 0.015) and systemic CRP levels (rs = 0.49, P = 0.024). Compared with non-cachectic subjects, cachectic patients had a higher relative abundance of intramyocellular glycerophospholipids and a lower relative abundance of glycerolipids. Furthermore, increases in several intramyocellular lipids such as SM(d36:1), PC(34:1), and TG(48:1) were found in cachectic patients with inflammation and correlated with specific cachexia features. Altered intramyocellular lipid species such as PC(34:1), LPC(18:2), and TG(48:1) showed an uneven distribution in muscle sections of cachectic and non-cachectic patients, with areas featuring abundance of these lipids next to areas almost devoid of them.

CONCLUSIONS

Intramyocellular lipid accumulation in patients with cachexia is associated with both local and systemic inflammation, and characterized by changes in defined lipid species such as glycerolipids and glycerophospholipids.

PF-05231023 reduces lipid deposition in apolipoprotein E-deficient mice by inhibiting the expression of lipid synthesis genes

Fibroblast growth factor 21 (FGF21) is a peptide hormone that is primarily expressed and secreted by the liver. The hormone is crucial for regulation of glucose homeostasis, lipid metabolism, and energy balance. Compared with natural FGF21, FGF21 analogs have become drug candidates for the treatment of cardiovascular and metabolic diseases owing to their long half-life and greater stability in vitro. Apolipoprotein E (Apoe)-knockout (Apoe -/-) mice exhibit progressive disruptions in lipid metabolism in vivo and develop further atherosclerosis pathological features owing to Apoe deletion. Therefore, this study used an Apoe -/- mouse model to investigate the effects of a long-acting FGF21 analog (PF-05231023) on lipid metabolism and related parameters. Eighteen Apoe -/- female mice were fed a Western diet equivalent for 12 weeks, and then randomly assigned to intraperitoneally receive either physiological saline (the control group) or 10 mg/kg PF-05231023 (the treatment group) three times a week for seven consecutive weeks. Body composition, glucose tolerance, blood and liver cholesterol, triglyceride levels, liver vacuolization levels, peri-ovarian white adipocyte hypertrophy, aortic atherosclerotic plaque formation, and the expression of genes related to lipid metabolism in adipose tissue were subsequently assessed before and after treatment. The aortic atherosclerotic plaque area was reduced in mice in the PF-05231023 treatment group compared with that in the saline group. Although the effect of PF-05231023 on the plasma biochemical indexes of mice was small, it significantly reduced lipid levels and lipid droplet accumulation in the liver, and reduced adipocyte hypertrophy in white adipose tissue. Transcriptome analysis of adipose tissue showed that PF-05231023 treatment downregulated the expression of lipid synthesis-related genes and inhibited the sterol regulatory element binding transcription factor 1 gene, thereby improving lipid deposition. PF-05231023 effectively improved the lipid metabolism of Apoe -/- mice, demonstrating an anti-atherosclerotic effect and providing a scientific basis and experimental foundation for the clinical treatment of cardiovascular diseases by using long-acting FGF21 analogs.

Correlation between environmental pollutant exposure and cardiopulmonary health by serum biomarker analysis in the Swedish elderly population

Persistent organic pollutants (POPs) affect human health through the aryl hydrocarbon receptor (AhR) pathway and are implicated in mitochondrial dysfunction. Using data from the PIVUS study, we investigated the associations of serum AhR ligand (POP)-mediated luciferase activity (AhRL), mitochondrial ATP production inhibiting substances (MIS-ATP), and those affecting reactive oxygen species (MIS-ROS) with several metabolic syndrome (MetS) and cardiopulmonary function parameters. These include insulin resistance (HOMA-IR), inflammation, oxidative stress, and cardiopulmonary variables (FVC, FEV1, LV-EF, CCA distensibility). MIS-ATP showed significant correlations with HOMA-IR and pulmonary functions, indicating its direct impact of MIS-ATP on metabolic and pulmonary health. MIS-ROS correlated with oxidative stress markers and CCA distensibility, suggesting a role in systemic inflammatory responses. This study highlights the intricate relationships between environmental pollutant mixture and cardiopulmonary health in MetS as indicated by biomarkers of POP exposure in the elderly population, suggesting POP exposure may influence MetS onset and progression through mitochondrial dysfunction.

Hepatokines: unveiling the molecular and cellular mechanisms connecting hepatic tissue to insulin resistance and inflammation

Insulin resistance arising from Non-Alcoholic Fatty Liver Disease (NAFLD) stands as a prevalent global ailment, a manifestation within societies stemming from individuals' suboptimal dietary habits and lifestyles. This form of insulin resistance emerges as a pivotal factor in the development of type 2 diabetes mellitus (T2DM). Emerging evidence underscores the significant role of hepatokines, as hepatic-secreted hormone-like entities, in the genesis of insulin resistance and eventual onset of type 2 diabetes. Hepatokines exert influence over extrahepatic metabolism regulation. Their principal functions encompass impacting adipocytes, pancreatic cells, muscles, and the brain, thereby playing a crucial role in shaping body metabolism through signaling to target tissues. This review explores the most important hepatokines, each with distinct influences. Our review shows that Fetuin-A promotes lipid-induced insulin resistance by acting as an endogenous ligand for Toll-like receptor 4 (TLR-4). FGF21 reduces inflammation in diabetes by blocking the nuclear translocation of nuclear factor-κB (NF-κB) in adipocytes and adipose tissue, while also improving glucose metabolism. ANGPTL6 enhances AMPK and insulin signaling in muscle, and suppresses gluconeogenesis. Follistatin can influence insulin resistance and inflammation by interacting with members of the TGF-β family. Adropin show a positive correlation with phosphoenolpyruvate carboxykinase 1 (PCK1), a key regulator of gluconeogenesis. This article delves into hepatokines' impact on NAFLD, inflammation, and T2DM, with a specific focus on insulin resistance. The aim is to comprehend the influence of these recently identified hormones on disease development and their underlying physiological and pathological mechanisms.

Edible bird's nest regulates glucose and lipid metabolic disorders via the gut-liver axis in obese mice

Edible bird's nest (EBN) is a traditional food known for its nourishing and functional properties and is found to be involved in anti-oxidation, anti-aging, and anti-influenza mechanisms, immune regulation, and improving cardiovascular diseases, among others. However, the potential of EBN to improve glycolipid metabolism disorders in high-fat-diet induced obesity and the underlying mechanisms remain unexplored. We examined the effects of EBN on glycolipid metabolism in obese mice fed a high-fat diet. Male C57BL/6J mice were fed a high-fat diet for 8 weeks to establish an obesity model. The obese mice were selected and divided into six groups: two model control groups (normal and high-fat diets) and four intervention groups [Neu5Ac and low-, medium-, and high-dose EBN], with 12 mice in each group. After 10 weeks of continuous gavage intervention, only mice in the high-dose EBN intervention group had lower body weight and total fat content, especially visceral fat. Meanwhile, intervention with three doses of EBN reduced serum FBG, TC, LDL, Ox-LDL, IL-1β, IL-6, and TNF-α levels and increased serum HDL levels and energy expenditure. Using the high dosage as a paradigm, EBN intervention increased the sialic acid content in LDL, decreased TMAO in the liver, and increased GLP-1 levels in sera. EBN increased the colonic abundances of Akkermansia, Lactobacillus, and Desulfovibrio and reduced those of Lysinibacillus and Bacillus. The changes in the microbial community contribute to increasing colonic bile acids, reducing lipopolysaccharide synthesis to protect the intestinal barrier, and lowering inflammation levels. Changes were also observed in colonic transcripts and metabolites and liver gene transcripts and metabolites, which were mainly enriched in pathways of glycolipid metabolism, immune function amelioration, inflammatory signal mitigation, circadian rhythm, bile acid metabolism and insulin resistance. Therefore, EBN may enhance the gut microbiota and intestinal immunity, relieve chronic inflammation levels in serum, improve antioxidant capacity and circadian rhythm in the liver, promote bile acid metabolism, and decrease lipid absorption and lipid synthesis via the gut-liver axis. Consequently, this may reduce blood lipid and fat accumulation as well as improve islet function and reduce blood glucose levels.

Metabolic score for insulin resistance (METS-IR) predicts all-cause and cardiovascular mortality in the general population: evidence from NHANES 2001-2018

BACKGROUND

The prevalence of obesity-associated insulin resistance (IR) is increasing along with the increase in obesity rates. In this study, we compared the predictive utility of four alternative indexes of IR [triglyceride glucose index (TyG index), metabolic score for insulin resistance (METS-IR), the triglyceride/high-density lipoprotein cholesterol (TG/HDL-C) ratio and homeostatic model assessment of insulin resistance (HOMA-IR)] for all-cause mortality and cardiovascular mortality in the general population based on key variables screened by the Boruta algorithm. The aim was to find the best replacement index of IR.

METHODS

In this study, 14,653 participants were screened from the National Health and Nutrition Examination Survey (2001-2018). And TyG index, METS-IR, TG/HDL-C and HOMA-IR were calculated separately for each participant according to the given formula. The predictive values of IR replacement indexes for all-cause mortality and cardiovascular mortality in the general population were assessed.

RESULTS

Over a median follow-up period of 116 months, a total of 2085 (10.23%) all-cause deaths and 549 (2.61%) cardiovascular disease (CVD) related deaths were recorded. Multivariate Cox regression and restricted cubic splines analysis showed that among the four indexes, only METS-IR was significantly associated with both all-cause and CVD mortality, and both showed non-linear associations with an approximate "U-shape". Specifically, baseline METS-IR lower than the inflection point (41.33) was negatively associated with mortality [hazard ratio (HR) 0.972, 95% CI 0.950-0.997 for all-cause mortality]. In contrast, baseline METS-IR higher than the inflection point (41.33) was positively associated with mortality (HR 1.019, 95% CI 1.011-1.026 for all-cause mortality and HR 1.028, 95% CI 1.014-1.043 for CVD mortality). We further stratified the METS-IR and showed that significant associations between METS-IR levels and all-cause and cardiovascular mortality were predominantly present in the nonelderly population aged < 65 years.

CONCLUSIONS

In conjunction with the results of the Boruta algorithm, METS-IR demonstrated a more significant association with all-cause and cardiovascular mortality in the U.S. population compared to the other three alternative IR indexes (TyG index, TG/HDL-C and HOMA-IR), particularly evident in individuals under 65 years old.

Relationship between four insulin resistance surrogates and regression to normoglycemia from prediabetes among Chinese adults: A longitudinal Cohort Study

PURPOSE

We aimed to investigate the association of the triglyceride glucose-body mass index(TyG-BMI), metabolic score for insulin resistance (METS-IR) with regression to normoglycaemia, and further to compare the value of the four insulin resistance(IR) related indices(TyG-BMI, METS-IR, TyG and triglyceride to high-density lipoprotein cholesterol (TG/HDL-C) ratio) in identifying regressions to normoglycaemia from prediabetes.

METHODS

A total of 15,025 patients with prediabetes from the DATA-DRYAD database were included. Cox proportional hazards regression models and restricted cubic spline functions were performed to explore the association and nonlinearity between the indices with the incidence rate of normoglycaemia. Sensitivity and subgroup analyses evaluated the robustness of our findings.

RESULTS

Compared with the first quintile, TyG-BMI and METS-IR was negatively linked with the probability of regression to normoglycaemia from prediabetes, the adjusted effect size of the highest quintiles of METS-IR were the most obvious (HR:0.456,95% CI:0.4-0.519), followed by TG/HDL (HR:0.792, 95% CI:0.733-0.856), TyG-BMI (HR:0.816, 95% CI:0.73-0.911) and TyG (HR:0.841, 95% CI: 0.754-0.937) (all p for trend <0.001). A 1.0 SD increase in METS-IR induced a 43% decrease in the probability of regression to normoglycaemia, with 9.8% for TyG-BMI. There were nonlinear associations between TyG-BMI and METS-IR and outcomes, with the inflection point of the TyG-BMI being 218.2 and that of the METS-IR being 37.

CONCLUSIONS

The METS-IR might be the most superior indicator among the four non-insulin indices in identifying regressions to normoglycaemia from prediabetes in clinical application. The inflection points of the METS-IR and TyG-BMI may be instructive therapeutic points for assessing the status of prediabetes in advance and making more appropriate management and health care decisions.

Identifying the Risk Factors of Adverse Pregnancy Outcomes among Women with COVID-19: A Population-Based Case-Control Study in Southern Iran

Introduction

Pregnant women and their fetuses are considered as high-risk groups during the COVID-19 pandemic. The aim of this study was to identify the risk factors of adverse pregnancy outcomes among women with COVID-19.

Methods

This case-control study was conducted among pregnant women who delivered live infants at least 60 days before data collection in Hormozgan Province, south of Iran, 2021. The case and control groups included women with and without the history of COVID-19, respectively. A 47-item checklist including demographic information of the mothers, maternal current and past medical history, maternal and fetal prenatal and post-natal outcomes; and other COVID-19 related outcomes was used. The logistic regression analysis was used for data analysis.

Results

A total of 1337 women (668 in case and 669 in control groups) participated in this study. The mean (SD) gestational age in the case and control groups were 32.83 (84.64) and 23.75 (6.93) weeks respectively. Maternal age and the incidence of abortion, obesity, and multiple pregnancies was higher in the COVID-19 group compared with the control group. The most common COVID-19 symptoms were myalgia (24.8%), cough (19.3%), fever (17.5%) and olfactory disorder (14.3%). The preventive factors against COVID-19 adverse pregnancy outcomes were low and normal body mass index, influenza vaccination history, and multivitamin consumption, while the risk factors were multiple pregnancies, abortion and preterm labor.

Conclusion

This study showed that pregnant women were to COVID-19. The identified risk factors for COVID-19 adverse pregnancy outcomes can be used to prioritized pregnant women in receiving COVID-19 related health services.

Identification of ibuprofen targeting CXCR family members to alleviate metabolic disturbance in lipodystrophy based on bioinformatics and in vivo experimental verification

Background

Lipodystrophy is a rare disease that is poorly diagnosed due to its low prevalence and frequent phenotypic heterogeneity. The main therapeutic measures for patients with clinical lipodystrophy are aimed at improving general metabolic complications such as diabetes mellitus, insulin resistance, and hypertriglyceridemia. Therefore, there is an urgent need to find new biomarkers to aid in the diagnosis and targeted treatment of patients with congenital generalized lipodystrophy (CGL).

Methods

Dataset GSE159337 was obtained via the Gene Expression Omnibus database. First, differentially expressed genes (DEGs) between CGL and control samples were yielded via differential expression analysis and were analyzed for Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment to explore the functional pathways. Next, protein-protein interaction analysis and the MCC algorithm were implemented to yield candidate genes, which were then subjected to receiver operating characteristic (ROC) analysis to identify biomarkers with an area under the curve value exceeding 0.8. Moreover, random forest (RF), logistic regression, and support vector machine (SVM) analyses were carried out to assess the diagnostic ability of biomarkers for CGL. Finally, the small-molecule drugs targeting biomarkers were predicted, and ibuprofen was further validated in lipodystrophy mice.

Results

A total of 71 DEGs in GSE159337 were sifted out and were involved in immune receptor activity, immune response-regulating signaling pathway, and secretory granule membrane. Moreover, CXCR2, TNFSF10, NLRC4, CCR2, CEACAM3, TLR10, TNFAIP3, and JUN were considered as biomarkers by performing ROC analysis on 10 candidate genes. Meanwhile, RF, logistic regression, and SVM analyses further described that those biomarkers had an excellent diagnosis capability for CGL. Eventually, the drug-gene network included ibuprofen-CXCR1, ibuprofen-CXCR1, cenicriviroc-CCR2, fenofibrate-JUN, and other relationship pairs. Ibuprofen treatment was also validated to downregulate CXCR1 and CXCR2 in peripheral blood mononuclear cells (PBMCs) and improve glucose tolerance, hypertriglyceridemia, hepatic steatosis, and liver inflammation in lipodystrophy mice.

Conclusion

Eight biomarkers, namely, CXCR2, TNFSF10, NLRC4, CCR2, CEACAM3, TLR10, TNFAIP3, and JUN, were identified through bioinformatic analyses, and ibuprofen targeting CXCR1 and CXCR2 in PBMCs was shown to improve metabolic disturbance in lipodystrophy, contributing to studies related to the diagnosis and treatment of lipodystrophy.

Insulin resistance during androgen deprivation therapy in men with prostate cancer

BACKGROUND

Androgen deprivation therapy (ADT) in prostate cancer (PCa) has been associated with development of insulin resistance. However, the predominant site of insulin resistance remains unclear.

METHODS

The ADT & Metabolism Study was a single-center, 24-week, prospective observational study that enrolled ADT-naive men without diabetes who were starting ADT for at least 24 weeks (ADT group, n = 42). The control group comprised men without diabetes with prior history of PCa who were in remission after prostatectomy (non-ADT group, n = 23). Prevalent diabetes mellitus was excluded in both groups using all three laboratory criteria defined in the American Diabetes Association guidelines. All participants were eugonadal at enrollment. The primary outcome was to elucidate the predominant site of insulin resistance (liver or skeletal muscle). Secondary outcomes included assessments of body composition, and hepatic and intramyocellular fat. Outcomes were assessed at baseline, 12, and 24 weeks.

RESULTS

At 24 weeks, there was no change in hepatic (1.2; 95% confidence interval [CI], -2.10 to 4.43; p = .47) or skeletal muscle (-3.2; 95% CI, -7.07 to 0.66; p = .10) insulin resistance in the ADT group. No increase in hepatic or intramyocellular fat deposition or worsening of glucose was seen. These changes were mirrored by those observed in the non-ADT group. Men undergoing ADT gained 3.7 kg of fat mass.

CONCLUSIONS

In men with PCa and no diabetes, 24 weeks of ADT did not change insulin resistance despite adverse body composition changes. These findings should be reassuring for treating physicians and for patients who are being considered for short-term ADT.

Changes in the combination of the triglyceride-glucose index and obesity indicators estimate the risk of cardiovascular disease

BACKGROUND

Cardiovascular disease (CVD) is closely associated with the triglyceride glucose (TyG) index and its related indicators, particularly its combination with obesity indices. However, there is limited research on the relationship between changes in TyG-related indices and CVD, as most studies have focused on baseline TyG-related indices.

METHODS

The data for this prospective cohort study were obtained from the China Health and Retirement Longitudinal Study. The exposures were changes in TyG-related indices and cumulative TyG-related indices from 2012 to 2015. The K-means algorithm was used to classify changes in each TyG-related index into four classes (Class 1 to Class 4). Multivariate logistic regressions were used to evaluate the associations between the changes in TyG-related indices and the incidence of CVD.

RESULTS

In total, 3243 participants were included in this study, of whom 1761 (54.4%) were female, with a mean age of 57.62 years at baseline. Over a 5-year follow-up, 637 (19.6%) participants developed CVD. Fully adjusted logistic regression analyses revealed significant positive associations between changes in TyG-related indices, cumulative TyG-related indices and the incidence of CVD. Among these changes in TyG-related indices, changes in TyG-waist circumference (WC) showed the strongest association with incident CVD. Compared to the participants in Class 1 of changes in TyG-WC, the odds ratio (OR) for participants in Class 2 was 1.41 (95% confidence interval (CI) 1.08-1.84), the OR for participants in Class 3 was 1.54 (95% CI 1.15-2.07), and the OR for participants in Class 4 was 1.94 (95% CI 1.34-2.80). Moreover, cumulative TyG-WC exhibited the strongest association with incident CVD among cumulative TyG-related indices. Compared to the participants in Quartile 1 of cumulative TyG-WC, the OR for participants in Quartile 2 was 1.33 (95% CI 1.00-1.76), the OR for participants in Quartile 3 was 1.46 (95% CI 1.09-1.96), and the OR for participants in Quartile 4 was 1.79 (95% CI 1.30-2.47).

CONCLUSIONS

Changes in TyG-related indices are independently associated with the risk of CVD. Changes in TyG-WC are expected to become more effective indicators for identifying individuals at a heightened risk of CVD.

Metabolic Score for Insulin Resistance and New-Onset Type 2 Diabetes in a Middle-Aged and Older Adult Population: Nationwide Prospective Cohort Study and Implications for Primary Care

BACKGROUND

The metabolic score for insulin resistance (METS-IR) has emerged as a noninsulin-based index for the approximation of insulin resistance (IR), yet longitudinal evidence supporting the utility of METS-IR in the primary prevention of type 2 diabetes mellitus (T2DM) remains limited.

OBJECTIVE

We aimed to investigate the longitudinal association between METS-IR, which combines fasting plasma glucose (FPG), lipid profiles, and anthropometrics that can be routinely obtained in resource-limited primary care settings, and the incidence of new-onset T2DM.

METHODS

We conducted a closed-cohort analysis of a nationwide, prospective cohort of 7583 Chinese middle-aged and older adults who were free of T2DM at baseline, sampled from 28 out of 31 provinces in China. We examined the characteristics of participants stratified by elevated blood pressure (BP) at baseline and new-onset T2DM at follow-up. We performed Cox proportional hazard regression analysis to explore associations of baseline METS-IR with incident T2DM in participants overall and in participants stratified by baseline BP. We also applied net reclassification improvement and integrated discrimination improvement to examine the incremental value of METS-IR.

RESULTS

During a mean follow-up period of 6.3 years, T2DM occurred in 527 participants, among which two-thirds (332/527, 62.9%; 95% CI 58.7%-67.1%) had baseline FPG<110 mg/dL. A SD unit increase in baseline METS-IR was associated with the first incidence of T2DM (adjusted hazard ratio [aHR] 1.33, 95% CI 1.22-1.45; P<.001) in all participants. We obtained similar results in participants with normal baseline BP (aHR 1.41, 95% CI 1.22-1.62; P<.001) and elevated baseline BP (aHR 1.29, 95% CI 1.16-1.44; P<.001). The predictive capability for incident T2DM was improved by adding METS-IR to FPG. In study participants with new-onset T2DM whose baseline FPG was <126 mg/dL and <110 mg/dL, 62.9% (332/527; 95% CI 60%-65.9%) and 58.1% (193/332; 95% CI 54.3%-61.9%) of participants had baseline METS-IR above the cutoff values, respectively.

CONCLUSIONS

METS-IR was significantly associated with new-onset T2DM, regardless of baseline BP level. Regular monitoring of METS-IR on top of routine blood glucose in clinical practice may add to the ability to enhance the early identification of primary care populations at risk for T2DM.

Resveratrol attenuates against high-fat-diet-promoted non-alcoholic fatty liver disease in rats mainly by targeting the miR-34a/SIRT1 axis

This study evaluated if miR-34a/SIRT1 signalling mediates the anti-hepatosteatotic effect of resveratrol (RSV) in high-fat-diet (HFD)-fed rats. Rats were divided into seven groups (n = 6/each) as control, control + miR-34a agomir negative control, HFD, HFD + miR-34a, HFD + RSV, HFD + RSV + Ex-527 (a SIRT1 inhibitor), and HFD + RSV + miR-34a agomir. After 8 weeks, RSV suppressed dyslipidemia, lowered fasting glucose and insulin levels, improved insulin sensitivity, and prevented hepatic lipid accumulation. These effects were associated with hepatic downregulation of SREBP1 and SREBP2, upregulation of PPARα, and acetylation of Nrf2 (activation) and NF-κβ p65 (inhibition). Also, RSV reduced the transcription of miR-34a and increased the nuclear localisation of SIRT1 in the livers, muscles, and adipose tissues of HFD-fed rats. All these effects were prevented by EX-527 and miR-34a agmir. In conclusion, RSV prevents HFD-induced insulin resistance and hepatic steatosis by suppressing miR-34a-induced activation of SIRT1.

The Effects of Crataegus pinnatifida and Wolfiporia extensa Combination on Diet-Induced Obesity and Gut Microbiota

Obesity is a multifactorial chronic metabolic disease with multiple complications. Crataegus pinnatifida (CP) and Wolfiporia extensa (WE) are traditional functional foods with improving metabolic health properties. This study demonstrated the effect of CP and WE combination on ameliorating obesity induced by a high-fat diet (HFD). Moreover, the CP-WE food pair ameliorated HFD-induced metabolic disorders, including glucose intolerance, insulin resistance, hyperlipidemia, and hepatic steatosis. 16S rRNA gene amplicon sequencing and analysis revealed that CP combined with WE reshaped the composition of gut microbiota in HFD-fed mice. Furthermore, correlation analysis revealed a substantial association between the obesity-related parameters and the shifts in predominant bacterial genera influenced by the food pair intervention. In conclusion, this study demonstrated that the CP-WE food pair ameliorated HFD-induced obesity and reshaped gut microbiota composition, providing a promising approach to combat obesity through specific food combinations.

Overnutrition, Hyperinsulinemia and Ectopic Fat: It Is Time for A Paradigm Shift in the Management of Type 2 Diabetes

The worldwide incidence of prediabetes/type 2 has continued to rise the last 40 years. In the same period, the mean daily energy intake has increased, and the quality of food has significantly changed. The chronic exposure of pancreatic β-cells to calorie excess (excessive energy intake) and food additives may increase pancreatic insulin secretion, decrease insulin pulses and/or reduce hepatic insulin clearance, thereby causing chronic hyperinsulinemia and peripheral insulin resistance. Chronic calorie excess and hyperinsulinemia may promote lipogenesis, inhibit lipolysis and increase lipid storage in adipocytes. In addition, calorie excess and hyperinsulinemia can induce insulin resistance and contribute to progressive and excessive ectopic fat accumulation in the liver and pancreas by the conversion of excess calories into fat. The personal fat threshold hypothesis proposes that in susceptible individuals, excessive ectopic fat accumulation may eventually lead to hepatic insulin receptor resistance, the loss of pancreatic insulin secretion, hyperglycemia and the development of frank type 2 diabetes. Thus, type 2 diabetes seems (partly) to be caused by hyperinsulinemia-induced excess ectopic fat accumulation in the liver and pancreas. Increasing evidence further shows that interventions (hypocaloric diet and/or bariatric surgery), which remove ectopic fat in the liver and pancreas by introducing a negative energy balance, can normalize insulin secretion and glucose tolerance and induce the sustained biochemical remission of type 2 diabetes. This pathophysiological insight may have major implications and may cause a paradigm shift in the management of type 2 diabetes: avoiding/reducing ectopic fat accumulation in the liver and pancreas may both be essential to prevent and cure type 2 diabetes.

Comparison of intramyocellular lipid metabolism in patients with diabetes and male athletes

Despite opposing insulin sensitivity and cardiometabolic risk, both athletes and patients with type 2 diabetes have increased skeletal myocyte fat storage: the so-called "athlete's paradox". In a parallel non-randomised, non-blinded trial (NCT03065140), we characterised and compared the skeletal myocyte lipid signature of 29 male endurance athletes and 30 patients with diabetes after undergoing deconditioning or endurance training respectively. The primary outcomes were to assess intramyocellular lipid storage of the vastus lateralis in both cohorts and the secondary outcomes were to examine saturated and unsaturated intramyocellular lipid pool turnover. We show that athletes have higher intramyocellular fat saturation with very high palmitate kinetics, which is attenuated by deconditioning. In contrast, type 2 diabetes patients have higher unsaturated intramyocellular fat and blunted palmitate and linoleate kinetics but after endurance training, all were realigned with those of deconditioned athletes. Improved basal insulin sensitivity was further associated with better serum cholesterol/triglycerides, glycaemic control, physical performance, enhanced post insulin receptor pathway signalling and metabolic sensing. We conclude that insulin-resistant, maladapted intramyocellular lipid storage and turnover in patients with type 2 diabetes show reversibility after endurance training through increased contributions of the saturated intramyocellular fatty acid pools. Clinical Trial Registration: NCT03065140: Muscle Fat Compartments and Turnover as Determinant of Insulin Sensitivity (MISTY).

Adipose tissue as a linchpin of organismal ageing

Ageing is a conserved biological process, modulated by intrinsic and extrinsic factors, that leads to changes in life expectancy. In humans, ageing is characterized by greatly increased prevalence of cardiometabolic disease, type 2 diabetes and disorders associated with impaired immune surveillance. Adipose tissue displays species-conserved, temporal changes with ageing, including redistribution from peripheral to central depots, loss of thermogenic capacity and expansion within the bone marrow. Adipose tissue is localized to discrete depots, and also diffusely distributed within multiple organs and tissues in direct proximity to specialized cells. Thus, through their potent endocrine properties, adipocytes are capable of modulating tissue and organ function throughout the body. In addition to adipocytes, multipotent progenitor/stem cells in adipose tissue play a crucial role in maintenance and repair of tissues throughout the lifetime. Adipose tissue may therefore be a central driver for organismal ageing and age-associated diseases. Here we review the features of adipose tissue during ageing, and discuss potential mechanisms by which these changes affect whole-body metabolism, immunity and longevity. We also explore the potential of adipose tissue-targeted therapies to ameliorate age-associated disease burdens.

Comprehensive Metabolomic Analysis of Human Heart Tissue Enabled by Parallel Metabolite Extraction and High-Resolution Mass Spectrometry

The heart contracts incessantly and requires a constant supply of energy, utilizing numerous metabolic substrates, such as fatty acids, carbohydrates, lipids, and amino acids, to supply its high energy demands. Therefore, a comprehensive analysis of various metabolites is urgently needed for understanding cardiac metabolism; however, complete metabolome analyses remain challenging due to the broad range of metabolite polarities, which makes extraction and detection difficult. Herein, we implemented parallel metabolite extractions and high-resolution mass spectrometry (MS)-based methods to obtain a comprehensive analysis of the human heart metabolome. To capture the diverse range of metabolite polarities, we first performed six parallel liquid-liquid extractions (three monophasic, two biphasic, and one triphasic) of healthy human donor heart tissue. Next, we utilized two complementary MS platforms for metabolite detection: direct-infusion ultrahigh-resolution Fourier-transform ion cyclotron resonance (DI-FTICR) and high-resolution liquid chromatography quadrupole time-of-flight tandem MS (LC-Q-TOF-MS/MS). Using DI-FTICR MS, 9644 metabolic features were detected where 7156 were assigned a molecular formula and 1107 were annotated by accurate mass assignment. Using LC-Q-TOF-MS/MS, 21,428 metabolic features were detected where 285 metabolites were identified based on fragmentation matching against publicly available libraries. Collectively, 1340 heart metabolites were identified in this study, which span a wide range of polarities including polar (benzenoids, carbohydrates, and nucleosides) as well as nonpolar (phosphatidylcholines, acylcarnitines, and fatty acids) compounds. The results from this study will provide critical knowledge regarding the selection of appropriate extraction and MS detection methods for the analysis of the diverse classes of human heart metabolites.

Association of anthropometric measures with all-cause and cause-specific mortality in US adults: revisiting the obesity paradox

OBJECTIVE

Previous studies have shown that the obesity paradox exists in a variety of clinical settings, whereby obese individuals have lower mortality than their normal-weight counterparts. It remains unclear whether the association between obesity and mortality risk varies by anthropometric measures. The purpose of this study is to examine the association between various anthropometric measures and all-cause and cause-specific mortality in US adults.

METHODS

This cohort study included data from the National Health and Nutrition Examination Survey between 2009 and 2018, with a sample size of 28,353 individuals weighted to represent 231 million US adults. Anthropometric measurements were obtained by trained technicians using standardized methods. Mortality data were collected from the date of enrollment through December 31, 2019. Weighted Cox proportional hazards models, restricted cubic spline curves, and cumulative incidence analyses were performed.

RESULTS

A total of 2091 all-cause deaths, 606 cardiovascular deaths, 519 cancer deaths, and 966 other-cause deaths occurred during a median follow-up of 5.9 years. The association between body mass index (BMI) and mortality risk was inversely J-shaped, whereas the association between waist-to-height ratio (WHtR) and mortality risk was positively J-shaped. There was a progressive increase in the association between the WHtR category and mortality risk. Compared with the reference category of WHtR < 0.5, the estimated hazard ratio (HR) for all-cause mortality was 1.004 (95% confidence interval [CI] 1.001-1.006) for WHtR 0.50-0.59, 1.123 (95% CI 1.120-1.127) for WHtR 0.60-0.69, 1.591 (95% CI 1.584-1.598) for WHtR 0.70-0.79, and 2.214 (95% CI 2.200-2.228) for WHtR ≥ 0.8, respectively. Other anthropometric indices reflecting central obesity also showed that greater adiposity was associated with higher mortality.

CONCLUSIONS

Anthropometric measures reflecting central obesity were independently and positively associated with mortality risk, eliminating the possibility of an obesity paradox.

Changes in mesenteric fat thickness and its clinical impact in bariatric surgery

Obesity, especially central obesity is associated with increased risk of metabolic syndrome, non-alcoholic fatty liver disease (NAFLD) and type 2 diabetes mellitus. The study aimed to investigate the associations of the changes of abdominal fat thicknesses with changes of anthropometric indexes and improvements of metabolic phenotypes in patients with obesity and T2DM before and after bariatric surgery. Between April 2016 and January 2017, 34 adult patients with concurrent obesity and T2DM scheduled for different bariatric surgeries were prospectively evaluated by ultrasound before and 1-year after bariatric surgery to determine abdominal fat thicknesses (mesenteric fat, preperitoneal fat and subcutaneous fat) and NAFLD. At 1 year, of the 25 patients that finished the study, significant decrease in mesenteric-fat-thickness was associated with significant reduction of obesity, that is, BMI (-24%, p < .001), remission of metabolic syndrome (32%, p = .008), NAFLD (60%, p < .001) and T2DM (44%, p < .001). Lower baseline mesenteric fat thickness was associated with remission of metabolic syndrome. Lower baseline mesenteric-fat-thickness may have the potential to predict metabolic syndrome remission after bariatric surgery.

Modelling remission from overweight type 2 diabetes reveals how altering advice may counter relapse

The development or remission of diet-induced overweight type 2 diabetes involves many biological changes which occur over very different timescales. Remission, defined by HbA1c<6.5%, or fasting plasma glucose concentration G<126 mg/dl, may be achieved rapidly by following weight loss guidelines. However, remission is often short-term, followed by relapse. Mathematical modelling provides a way of investigating a typical situation, in which patients are advised to lose weight and then maintain fat mass, a slow variable. Remission followed by relapse, in a modelling sense, is equivalent to changing from a remission trajectory with steady state G<126 mg/dl, to a relapse trajectory with steady state G≥126 mg/dl. Modelling predicts that a trajectory which maintains weight will be a relapse trajectory, if the fat mass chosen is too high, the threshold being dependent on the lipid to carbohydrate ratio of the diet. Modelling takes into account the effects of hepatic and pancreatic lipid on hepatic insulin sensitivity and β-cell function, respectively. This study leads to the suggestion that type 2 diabetes remission guidelines be given in terms of model parameters, not variables; that is, the patient should adhere to a given nutrition and exercise plan, rather than achieve a certain subset of variable values. The model predicts that calorie restriction, not weight loss, initiates remission from type 2 diabetes; and that advice of the form 'adhere to the diet and exercise plan' rather than 'achieve a certain weight loss' may help counter relapse.

Adipose Tissue Inflammation: Linking Physiological Stressors to Disease Susceptibility

The study of adipose tissue (AT) is enjoying a renaissance. White, brown, and beige adipocytes are being investigated in adult animals, and the critical roles of small depots like perivascular AT are becoming clear. But the most profound revision of the AT dogma has been its cellular composition and regulation. Single-cell transcriptomic studies revealed that adipocytes comprise well under 50% of the cells in white AT, and a substantial portion of the rest are immune cells. Altering the function of AT resident leukocytes can induce or correct metabolic syndrome and, more surprisingly, alter adaptive immune responses to infection. Although the field is dominated by obesity research, conditions such as rapid lipolysis, infection, and heat stress impact AT immune dynamics as well. Recent findings in rodents lead to critical questions that should be explored in domestic livestock as potential avenues for improved animal resilience to stressors, particularly as animals age.

Effects of Clostridium tyrobutyricum on Lipid Metabolism, Intestinal Barrier Function, and Gut Microbiota in Obese Mice Induced by High-Fat Diet

Obesity and its complications constitute a main threat to global human health. The purpose of this investigation was to explore the influences of Clostridium tyrobutyricum (Ct) on lipid metabolism, intestinal barrier function, and intestinal microbiome in obese mice induced by a high-fat diet (HFD). After establishing the obesity model, 107 CFU/mL and 108 CFU/mL C. tyrobutyricum were used to intervene in HFD-fed mice by gavage for six weeks, and indexes related to obesity were measured. In the liver of HFD-fed mice, the results revealed that C. tyrobutyricum reduced liver weight and the levels of triglyceride (TG), total cholesterol (TC), and nonesterified fatty acid (NEFA), along with decreasing red lipid droplets and fat vacuoles. After C. tyrobutyricum intervention, the mRNA expression of peroxisome proliferator-activated receptor-γ (PPARγ) was downregulated, and AMP-activated protein kinase (AMPK), peroxisome proliferator-activated receptor-α (PPARα), adipose triglyceride lipase (ATGL), and hormone-sensitive lipase (HSL) were upregulated in the liver. Additionally, C. tyrobutyricum alleviated intestinal morphology injury caused by HFD, decreased the expression of tumor necrosis factor-α (TNF-α), interleukin 6 (IL-6), and IL-1β in the colon, and upregulated tight junction protein expression. In addition, 16S rRNA sequencing revealed that C. tyrobutyricum increases the diversity of intestinal microbiota. Overall, C. tyrobutyricum improved HFD-induced lipid metabolism disorders, preserved the intestinal barrier's integrity, and modulated the structure of the intestinal microbiome. These findings provide a novel insight into the role of C. tyrobutyricum as a probiotic in regulating lipid metabolism.

Phenotyping obesity: A focus on metabolically healthy obesity and metabolically unhealthy normal weight

Over the past 4 decades, research has shown that having a normal body weight does not automatically imply preserved metabolic health and a considerable number of lean individuals harbour metabolic abnormalities typically associated with obesity. Conversely, excess adiposity does not always equate with an abnormal metabolic profile. In fact, evidence exists for the presence of a metabolically unhealthy normal weight (MUHNW) and a metabolically healthy obese (MHO) phenotype. It has become increasingly recognised that different fat depots exert different effects on the metabolic profile of each individual by virtue of their location, structure and function, giving rise to these different body composition phenotypes. Furthermore, other factors have been implicated in the aetiopathogenesis of the body composition phenotypes, including genetics, ethnicity, age and lifestyle/behavioural factors. Even though to date both MHO and MUHNW have been widely investigated and documented in the literature, studies report different outcomes on long-term cardiometabolic morbidity and mortality. Future large-scale, observational and population-based studies are required for better profiling of these phenotypes as well as to further elucidate the pathophysiological role of the adipocyte in the onset of metabolic disorders to allow for better risk stratification and a personalised treatment paradigm.

Ceramide enhanced the hepatic glucagon response through regulation of CREB activity

BACKGROUND & AIMS

Hyperglycemia is associated with lipid disorders in patients with diabetes. Ceramides are metabolites involved in sphingolipid metabolism that accumulate during lipid disorders and exert deleterious effects on glucose and lipid metabolism. However, the effects of ceramide on glucagon-mediated hepatic gluconeogenesis remain largely unknown. This study was designed to investigate the impact of ceramides on gluconeogenesis in the context of the hepatic glucagon response, with the aim of finding new pharmacological interventions for hyperglycemia in diabetes.

METHODS

Liquid chromatography-mass spectrometry was used to quantify ceramide content in the serum of patients with diabetes. Primary hepatocytes were isolated from male C57BL/6J mice to study the effects of ceramide on hepatic glucose production. Immunofluorescence staining was performed to view cAMP-responsive element-binding protein (CREB)- regulated transcription co-activator 2 (CRTC2) nuclear translocation in hepatocytes. Serine palmitoyl-transferase, long chain base subunit 2 (Sptlc2) knockdown mice were generated using an adeno-associated virus containing shRNA, and hepatic glucose production was assessed glucagon tolerance and pyruvate tolerance tests in mice fed a normal chow diet and high-fat diet.

RESULTS

Increased ceramide levels were observed in the serum of patients newly diagnosed with type 2 diabetes. De novo ceramide synthesis was activated in mice with metabolic disorders. Ceramide enhanced hepatic glucose production in primary hepatocytes. In contrast, genetic silencing of Sptlc2 prevented this process. Mechanistically, ceramides de-phosphorylate CRTC2 (Ser 171) and facilitate its translocation into the nucleus for CREB activation, thereby augmenting the hepatic glucagon response. Hepatic Sptlc2 silencing blocked ceramide generation in the liver and thus restrained the hepatic glucagon response in mice fed a normal chow diet and high-fat diet.

CONCLUSIONS

These data indicate that ceramide serves as an intracellular messenger that augments hepatic glucose production by regulating CRTC2/CREB activity in the context of the hepatic glucagon response, suggesting that CRTC2 phosphorylation might be a potential node for pharmacological interventions to restrain the hyperglycemic response during fasting in diabetes.

Gastric Submucosal Fat Accumulation Is Associated with Insulin Resistance in Patients with Obesity

PURPOSE

Ectopic fat accumulation plays a significant role in obesity-related metabolic dysfunction, and few studies have reported an association between ectopic gastric fat and metabolic risk factors. We aim to fulfill this need by assessing the degree of gastric submucosal fat accumulation in pathologic sections of 190 sleeve gastrectomy specimens.

METHODS

Study patients were divided into two groups (D1 and D2) based on whether fat accumulation exceeded 1/3 of the submucosa of the stomach. Demographic and metabolic risk factors were compared between the two groups. Metabolic risk variables that might be associated with the degree of fat accumulation were screened in the original cohort. After balancing for possible confounders, the robustness of the correlations was assessed using binary and conditional logistic regression analyses.

RESULTS

All study patients had fat accumulation in the submucosa of the stomach. C-reactive protein (CRP), body mass index (BMI), visceral fat area (VFA), and insulin resistance (IR) were higher in the D2 group than in the D1 group in the original cohort (P < 0.05). Logistic regression analysis showed that BMI and IR may be associated with increased fat accumulation. After balancing variables other than obesity indicators and IR using propensity score matching, BMI and IR remained significantly different between the two groups (P < 0.05). Further analysis of the matched cohort using two logistic regression analyses showed that IR was an independent risk factor for increased fat accumulation.

CONCLUSION

This study indicated that gastric submucosal fat accumulation was prevalent in patients with obesity and was associated with IR.

Effects of liraglutide on intrapancreatic fat deposition in patients with type 2 diabetes

BACKGROUND & AIMS

Ectopic fat deposition is associated with worsening of glycemic control. This study was conducted to determine whether liraglutide reduces ectopic fat deposition, especially in pancreas, in patients with type 2 diabetes (T2D).

METHODS

We retrospectively recruited T2D patients who underwent abdominal unenhanced CT scans both before and after administration of liraglutide (N = 13) or glimepiride (N = 29). Using CT values of pancreas (P), liver (L) and spleen (S), we defined the indices of intrapancreatic and liver fat as P-S value and L-S value, respectively. Increase of each value suggests the reduction of each fat deposition.

RESULTS

The values of HbA1c (p = 0.0017) and body weight (p = 0.0081) decreased, and L-S (p = 0.0024) increased significantly after administration of liraglutide compared with those at baseline. Similarly, P-S tended to increase in the liraglutide group (p = 0.0547) and increased significantly in the liraglutide subgroup with fatty pancreas (p = 0.0303), defined as having baseline P-S less than -5. In the glimepiride group, P-S did not increase regardless of baseline P-S. Among patients with fatty pancreas, administration of liraglutide tended to be a significant factor for the change in P-S after adjustment for the change in HbA1c (p = 0.1090) and the change in visceral fat area (p = 0.1030).

CONCLUSIONS

Intrapancreatic fat deposition was decreased after treatment with liraglutide, but not glimepiride, in T2D patients with fatty pancreas. Liraglutide might reduce intrapancreatic fat deposition independently of decreases in HbA1c and visceral fat volume.

Independent association of thigh muscle fat density with vascular events in Korean adults

BACKGROUND

We aimed to explore the associations between thigh muscle fat density and vascular events.

METHODS

A total of 3,595 adults (mean age, 57.2 years; women, 1,715 [47.7%]) without baseline cardiovascular events from the Korean Atherosclerosis Study-2 were included. Muscle and fat area at the mid-thigh level were measured by computed tomography (CT) using the following Hounsfield Unit range: 0-30 for low density muscle (LDM); 31-100 for normal density muscle (NDM); and - 250 to - 50 for fat.

RESULTS

During a median follow-up period of 11.8 (4.3-13.9) years, vascular events occurred in 11.6% of men and 5.9% of women. Individuals with vascular events had a larger LDM area (men: 48.8 ± 15.5 cm2 vs. 44.6 ± 14.5 cm2; women: 39.4 ± 13.2 cm2 vs. 35.0 ± 11.8 cm2, both P < 0.001) compared with those who did not have vascular events during the follow-up of at least 5 years. The LDM/NDM ratio was also independently associated with vascular events after adjusting for cardiometabolic risk factors. Moreover, the LDM/NDM ratio improved the prognostic value for vascular events when added to conventional risk factors.

CONCLUSIONS

The current study suggests that a higher thigh muscle fat infiltration is associated with an increased risk of developing vascular events among Korean adults.

CLSTN3B enhances adipocyte lipid droplet structure and function via endoplasmic reticulum contact

Interorganelle contacts facilitate material exchanges and sustain the structural and functional integrity of organelles. Lipid droplets (LDs) of adipocytes are responsible for energy storage and mobilization responding to body needs. LD biogenesis defects compromise the lipid-storing capacity of adipocytes, resulting in ectopic lipid deposition and metabolic disorders, yet how the uniquely large LDs in adipocytes attain structural and functional maturation is incompletely understood. Here we show that the mammalian adipocyte-specific protein CLSTN3B is crucial for adipocyte LD maturation. CLSTN3B employs an arginine-rich segment to promote extensive contact and hemifusion-like structure formation between the endoplasmic reticulum (ER) and LD, allowing ER-to-LD phospholipid diffusion during LD expansion. CLSTN3B ablation results in reduced LD surface phospholipid density, increased turnover of LD-surface proteins, and impaired LD functions. Our results establish the central role of CLSTN3B in the adipocyte-specific LD maturation pathway that enhances lipid storage and maintenance of metabolic health under caloric overload.

The roles of type 2 diabetes and obesity in disease activity and progression of non-alcoholic fatty liver disease/non-alcoholic steatohepatitis

OBJECTIVE

We examined the roles of type 2 diabetes (T2D) and obesity in disease activity and fibrosis progression/regression in patients with non-alcoholic fatty liver disease/non-alcoholic steatohepatitis (NAFLD/NASH).

METHODS

This multi-center, retrospective study included patients with suspected or histologically proven NAFLD/NASH from the NASH Clinical Research Network. Outcomes included disease activity and rate of fibrosis, assessed using liver-biopsy driven measures (NAFLD activity score [NAS] and fibrosis score [FS]). Logistic regression and doubly robu estimation of causal effects tested relationships among T2D, obesity, and NAFLD/NASH.

RESULTS

The analytical sample included 870 adult patients with baseline biopsy data and 157 patients with multiple biopsy data. Patients with NAFLD/NASH and T2D had significantly higher baseline average NAS (4.52 vs. 4.13; p = 0.009) and FS (2.17 vs. 1.56; p < 0.0001); those with T2D had a significantly greater reduction in average NAS over time (-0.77/year vs. -0.17/year; p = 0.0008). Change in FS over time did not differ significantly by T2D status (-0.23/year vs. -0.04/year; p = 0.34). Baseline NAS, baseline FS, and change in average NAS over time did not differ significantly by obesity status (4.17 vs. 4.47; p = 0.16; 1.73 vs.1.92; p = 0.31; -0.40/year vs. -0.59/year; p = 0.62, respectively). Patients with obesity had a slight increase in FS but those without obesity had a reduction in average FS over time (0.07/year vs. -0.27/year; p = 0.008).

CONCLUSIONS

Patients with NAFLD/NASH and T2D had greater baseline disease activity versus those without T2D, but there was greater regression of disease activity over time among those with T2D. Patients with NAFLD/NASH and obesity had worsening of fibrosis versus those without obesity. NCT00063622.