Hyperinsulinemia and insulin resistance in the obese may develop as part of a homeostatic response to elevated free fatty acids: A mechanistic case-control and a population-based cohort study

An adipocentric perspective of pancreatic lipotoxicity in diabetes pathogenesis

Obesity and diabetes represent two increasing and invalidating public health issues that often coexist. It is acknowledged that fat mass excess predisposes to insulin resistance and type 2 diabetes mellitus (T2D), with the increasing incidence of the two diseases significantly associated. Moreover, emerging evidence suggests that obesity might also accelerate the appearance of type 1 diabetes (T1D), which is now a relatively frequent comorbidity in patients with obesity. It is a common clinical finding that not all patients with obesity will develop diabetes at the same level of adiposity, with gender, genetic, and ethnic factors playing an important role in defining the timing of diabetes appearance. The adipose tissue (AT) expandability hypothesis explains this paradigm, indicating that the individual capacity to appropriately store energy surplus in the form of fat within the AT determines and prevents the toxic deposition of lipids in other organs, such as the pancreas. Thus, we posit that when the maximal storing capacity of AT is exceeded, individuals will develop T2D. In this review, we provide insight into mechanisms by which the AT controls pancreas lipid content and homeostasis in case of obesity to offer an adipocentric perspective of pancreatic lipotoxicity in the pathogenesis of diabetes. Moreover, we suggest that improving AT function is a valid therapeutic approach to fighting obesity-associated complications including diabetes.

Review article: Hepatic steatosis and its associations with acute and chronic liver diseases

BACKGROUND

Hepatic steatosis is a common finding in liver histopathology and the hallmark of metabolic dysfunction-associated steatotic liver disease (MASLD), formerly known as non-alcoholic fatty liver disease (NAFLD), whose global prevalence is rising.

AIMS

To review the histopathology of hepatic steatosis and its mechanisms of development and to identify common and rare disease associations.

METHODS

We reviewed literature on the basic science of lipid droplet (LD) biology and clinical research on acute and chronic liver diseases associated with hepatic steatosis using the PubMed database.

RESULTS

A variety of genetic and environmental factors contribute to the development of chronic hepatic steatosis or steatotic liver disease, which typically appears macrovesicular. Microvesicular steatosis is associated with acute mitochondrial dysfunction and liver failure. Fat metabolic processes in hepatocytes whose dysregulation leads to the development of steatosis include secretion of lipoprotein particles, uptake of remnant lipoprotein particles or free fatty acids from blood, de novo lipogenesis, oxidation of fatty acids, lipolysis and lipophagy. Hepatic insulin resistance is a key feature of MASLD. Seipin is a polyfunctional protein that facilitates LD biogenesis. Assembly of hepatitis C virus takes place on LD surfaces. LDs make important, functional contact with the endoplasmic reticulum and other organelles.

CONCLUSIONS

Diverse liver pathologies are associated with hepatic steatosis, with MASLD being the most important contributor. The biogenesis and dynamics of LDs in hepatocytes are complex and warrant further investigation. Organellar interfaces permit co-regulation of lipid metabolism to match generation of potentially toxic lipid species with their LD depot storage.

Alterations in nonesterified free fatty acid trafficking rather than hyperandrogenism contribute to metabolic health in obese women with polycystic ovary syndrome

OBJECTIVE

To determine whether alterations in nonesterified fatty acid (NEFA) dynamics or degree of hyperandrogenism (HA) contribute to the difference in insulin sensitivity between women with metabolically healthy obese polycystic ovary syndrome (PCOS) (MHO-PCOS) and women with metabolically unhealthy obese PCOS (MUO-PCOS).

DESIGN

Prospective cross-sectional study.

SETTING

Tertiary-care academic center.

PATIENTS

One hundred twenty-five obese women with PCOS.

INTERVENTION

Consecutive obese (body mass index [BMI] ≥ 30 kg/m2) oligo-ovulatory women (n = 125) with PCOS underwent an oral glucose tolerance test and a subgroup of 16 participants underwent a modified frequently sampled intravenous glucose tolerance test to determine insulin-glucose and -NEFA dynamics.

MAIN OUTCOME MEASURES

Degree of insulin resistance (IR) in adipose tissue (AT) basally (Adipo-IR) and dynamically (the nadir in NEFA levels observed [NEFAnadir], the time it took for NEFA levels to reach nadir [TIMEnadir], and the percent suppression in plasma NEFA levels from baseline to nadir [%NEFAsupp]); peak lipolysis rate (SNEFA) and peak rate of NEFA disposal from plasma pool (KNEFA); whole-body insulin-glucose interaction (acute response of insulin to glucose [AIRg], insulin sensitivity index [Si], glucose effectiveness [Sg], and disposition index [Di]); and HA (hirsutism score, total and free testosterone levels, and dehydroepiandrosterone sulfate levels).

RESULTS

A total of 85 (68%) women were MUO-PCOS and 40 (32%) were MHO-PCOS using the homeostasis model of assessment of IR. Subjects with MUO-PCOS and MHO-PCOS did not differ in mean age, BMI, waist-to-hip ratio, HA, and lipoprotein levels. By a modified frequently sampled intravenous glucose tolerance test, eight women with MUO-PCOS had lesser Si, KNEFA, and the percent suppression in plasma NEFA levels from baseline to nadir (%NEFAsupp) and greater TIMEnadir, NEFAnadir, and baseline adipose tissue IR index (Adipo-IR) than eight subjects with MHO-PCOS, but similar fasting NEFA levels and SNEFA. Women with MUO-PCOS had a higher homeostasis model of assessment-β% and fasting insulin levels than women with MHO-PCOS. In bivalent analysis, Si correlated strongly and negatively with Adipo-IR and NEFAnadir, weakly and negatively with TIMEnadir, and positively with KNEFA and %NEFAsupp, in women with MUO-PCOS only.

CONCLUSION

Independent of age and BMI, women with MUO-PCOS have reduced NEFA uptake and altered insulin-mediated NEFA suppression, but no difference in HA, compared with women with MHO-PCOS. Altered insulin-mediated NEFA suppression, rather than HA or lipolysis rate, contributes to variations in insulin sensitivity among obese women with PCOS.

Alterations in Adipose Tissue Distribution, Cell Morphology, and Function Mark Primary Insulin Hypersecretion in Youth With Obesity

Excessive insulin secretion independent of insulin resistance, defined as primary hypersecretion, is associated with obesity and an unfavorable metabolic phenotype. We examined the characteristics of adipose tissue of youth with primary insulin hypersecretion and the longitudinal metabolic alterations influenced by the complex adipo-insular interplay. In a multiethnic cohort of adolescents with obesity but without diabetes, primary insulin hypersecretors had enhanced model-derived β-cell glucose sensitivity and rate sensitivity but worse glucose tolerance, despite similar demographics, adiposity, and insulin resistance measured by both oral glucose tolerance test and euglycemic-hyperinsulinemic clamp. Hypersecretors had greater intrahepatic and visceral fat depots at abdominal MRI, hypertrophic abdominal subcutaneous adipocytes, higher free fatty acid and leptin serum levels per fat mass, and faster in vivo lipid turnover assessed by a long-term 2H2O labeling protocol. At 2-year follow-up, hypersecretors had greater fat accrual and a threefold higher risk for abnormal glucose tolerance, while individuals with hypertrophic adipocytes or higher leptin levels showed enhanced β-cell glucose sensitivity. Primary insulin hypersecretion is associated with marked alterations in adipose tissue distribution, cellularity, and lipid dynamics, independent of whole-body adiposity and insulin resistance. Pathogenetic insight into the metabolic crosstalk between β-cell and adipocyte may help to identify individuals at risk for chronic hyperinsulinemia, body weight gain, and glucose intolerance.

ARTICLE HIGHLIGHTS

An adipoincretin effect links adipostasis with insulin secretion

The current paradigm for the insulin system focuses on the phenomenon of glucose-stimulated insulin secretion and insulin action on blood glucose control. This historical glucose-centric perspective may have introduced a conceptual bias in our understanding of insulin regulation. A body of evidence demonstrating that in vivo variations in blood glucose and insulin secretion can be largely dissociated motivated us to reconsider the fundamental design of the insulin system as a control system for metabolic homeostasis. Here, we propose that a minimal glucose-centric model does not accurately describe the physiological behavior of the insulin system and propose a new paradigm focusing on the effects of incretins, arguing that under fasting conditions, insulin is regulated by an adipoincretin effect.

Adipocyte PI3K links adipostasis with baseline insulin secretion at fasting through an adipoincretin effect

Insulin-PI3K signaling controls insulin secretion. Understanding this feedback mechanism is crucial for comprehending how insulin functions. However, the role of adipocyte insulin-PI3K signaling in controlling insulin secretion in vivo remains unclear. Using adipocyte-specific PI3Kα knockout mice (PI3KαAdQ) and a panel of isoform-selective PI3K inhibitors, we show that PI3Kα and PI3Kβ activities are functionally redundant in adipocyte insulin signaling. PI3Kβ-selective inhibitors have no effect on adipocyte AKT phosphorylation in control mice but blunt it in adipocytes of PI3KαAdQ mice, demonstrating adipocyte-selective pharmacological PI3K inhibition in the latter. Acute adipocyte-selective PI3K inhibition increases serum free fatty acid (FFA) and potently induces insulin secretion. We name this phenomenon the adipoincretin effect. The adipoincretin effect operates in fasted mice with increasing FFA and decreasing glycemia, indicating that it is not primarily a control system for blood glucose. This feedback control system defines the rates of adipose tissue lipolysis and chiefly controls basal insulin secretion during fasting.

Trends in breast cancer mortality attributable to metabolic risks in Chinese women from 1990 to 2019: an age-period-cohort analysis

Objective

Metabolic risks (MRs) are the primary determinants of breast cancer (BC) mortality among women. This study aimed to examine the changing trends in BC mortality associated with MRs and explore how they related to age, time period, and birth cohorts in Chinese women aged 25 and above.

Methods

Data were sourced from the Global Burden of Disease Study 2019 (GBD2019). The BC mortality trajectories and patterns attributable to MRs were assessed using Joinpoint regression. The age-period-cohort (APC) model was employed to evaluate cohort and time period effects.

Results

The age-standardized mortality rate (ASMR) of BC mortality linked to MRs displayed an escalating trend from 1990 to 2019, demonstrating an average annual percentage change (AAPC) of 1.79% (95% CI: 1.69~1.87). AAPCs attributable to high fasting plasma glucose (HFPG) and high body mass index (HBMI) were 0.41% (95% CI: 0.32~0.53) and 2.75% (95% CI: 2.68~2.82), respectively. APC analysis revealed that BC mortality due to HBMI in women aged 50 and above showed a rise with age and mortality associated with HFPG consistently demonstrated a positive correlation with age. The impact of HBMI on BC mortality significantly outweighed that of HFPG. The risk of BC mortality linked to HBMI has steadily increased since 2005, while HFPG demonstrated a trend of initial increase followed by a decrease in the period effect. Regarding the cohort effect, the relative risk of mortality was greater in the birth cohort of women after the 1960s of MRs on BC mortality, whereas those born after 1980 displayed a slight decline in the relative risk (RR) associated with BC mortality due to HBMI.

Conclusion

This study suggests that middle-aged and elderly women should be considered as a priority population, and control of HBMI and HFPG should be used as a primary tool to control metabolic risk factors and effectively reduce BC mortality.

White adipocyte dysfunction and obesity-associated pathologies in humans

The prevalence of obesity and associated chronic diseases continues to increase worldwide, negatively impacting on societies and economies. Whereas the association between excess body weight and increased risk for developing a multitude of diseases is well established, the initiating mechanisms by which weight gain impairs our metabolic health remain surprisingly contested. In order to better address the myriad of disease states associated with obesity, it is essential to understand adipose tissue dysfunction and develop strategies for reinforcing adipocyte health. In this Review we outline the diverse physiological functions and pathological roles of human white adipocytes, examining our current knowledge of why white adipocytes are vital for systemic metabolic control, yet poorly adapted to our current obesogenic environment.

Liver Androgen Receptor Knockout Improved High-fat Diet Induced Glucose Dysregulation in Female Mice But Not Male Mice

Previous research has indicated that liver androgen receptors may play a role in modulating disease. This study aims to investigate the pathophysiology of high-fat diet (HFD) induced dysglycemia in male and female liver androgen receptor knockout (LivARKO) mice. We performed metabolic tests on LivARKO female and male mice fed a HFD or a control diet (from Research Diets Inc.) during months 1 or 2 after starting the diet. Additionally, we performed Western blot and quantitative real-time PCR analysis on the livers of the mice to examine intermediates in the insulin signaling pathway. LivARKO-HFD female mice displayed no difference in glucose tolerance compared to female LivARKO-Control (Con) mice, whereas in wild-type female mice, HFD impaired glucose tolerance (IGT). Our data suggests that starting at 1 month, LivARKO may be protecting female mice from HFD-induced metabolic dysfunction. LivARKO-HFD female mice displayed significantly worse insulin sensitivity at 15 minutes compared to LivARKO-Con female mice, but, strangely, LivARKO-HFD female mice had significantly better insulin sensitivity at 60 and 90 minutes compared to LivARKO-Con female mice. Despite protecting against IGT, LivARKO did not protect against HFD-induced hyperinsulinemia in female mice. In contrast to females, male LivARKO-HFD mice displayed impaired glucose tolerance compared to male LivARKO-Con mice. Thus, LivARKO is not protective against HFD-induced glucose metabolic dysfunction in male mice. Lastly, LivARKO-HFD female mice maintained hepatic insulin sensitivity whereas LivARKO-HFD male mice displayed hepatic insulin resistance. These findings suggest that LivARKO delayed the onset of HFD-induced dysglycemia in female mice.

Metabolic Flexibility of the Heart: The Role of Fatty Acid Metabolism in Health, Heart Failure, and Cardiometabolic Diseases

This comprehensive review explores the critical role of fatty acid (FA) metabolism in cardiac diseases, particularly heart failure (HF), and the implications for therapeutic strategies. The heart's reliance on ATP, primarily sourced from mitochondrial oxidative metabolism, underscores the significance of metabolic flexibility, with fatty acid oxidation (FAO) being a dominant source. In HF, metabolic shifts occur with an altered FA uptake and FAO, impacting mitochondrial function and contributing to disease progression. Conditions like obesity and diabetes also lead to metabolic disturbances, resulting in cardiomyopathy marked by an over-reliance on FAO, mitochondrial dysfunction, and lipotoxicity. Therapeutic approaches targeting FA metabolism in cardiac diseases have evolved, focusing on inhibiting or stimulating FAO to optimize cardiac energetics. Strategies include using CPT1A inhibitors, using PPARα agonists, and enhancing mitochondrial biogenesis and function. However, the effectiveness varies, reflecting the complexity of metabolic remodeling in HF. Hence, treatment strategies should be individualized, considering that cardiac energy metabolism is intricate and tightly regulated. The therapeutic aim is to optimize overall metabolic function, recognizing the pivotal role of FAs and the need for further research to develop effective therapies, with promising new approaches targeting mitochondrial oxidative metabolism and FAO that improve cardiac function.

Palmitate Stimulates Expression of the von Willebrand Factor and Modulates Toll-like Receptors Level and Activity in Human Umbilical Vein Endothelial Cells (HUVECs)

An increased concentration of palmitate in circulation is one of the most harmful factors in obesity. The von Willebrand factor (vWF), a protein involved in haemostasis, is produced and secreted by the vascular endothelium. An increased level of vWF in obese patients is associated with thrombosis and cardiovascular disease. The aim of this study was to investigate a palmitate effect on vWF in endothelial cells and understand the mechanisms of palmitate-activated signalling. Human umbilical vein endothelial cells (HUVECs) incubated in the presence of palmitate, exhibited an increased VWF gene expression, vWF protein maturation, and stimulated vWF secretion. Cardamonin, a Nuclear Factor kappa B (NF-κB) inhibitor, abolished the palmitate effect on VWF expression. The inhibition of Toll-like receptor (TLR) 2 with C29 resulted in the TLR4 overactivation in palmitate-treated cells. Palmitate, in the presence of TLR4 inhibitor TAK-242, leads to a higher expression of TLR6, CD36, and TIRAP. The silencing of TLR4 resulted in an increase in TLR2 level and vice versa. The obtained results indicate a potential mechanism of obesity-induced thrombotic complication caused by fatty acid activation of NF-κB signalling and vWF upregulation and help to identify various compensatory mechanisms related to TLR4 signal transduction.

Early insulin resistance in normoglycemic low-risk individuals is associated with subclinical atherosclerosis

BACKGROUND

Elevated glycated hemoglobin (HbA1c) is associated with a higher burden of subclinical atherosclerosis (SA). However, the association with SA of earlier insulin resistance markers is poorly understood. The study assessed the association between the homeostatic model assessment of insulin resistance index (HOMA-IR) and SA in addition to the effect of cardiovascular risk factors (CVRFs) in individuals with normal HbA1c.

METHODS

A cohort of 3,741 middle-aged individuals from the Progression of Early Subclinical Atherosclerosis (PESA) study with basal HbA1c < 6.0% (< 42 mmol/mol) and no known CV disease underwent extensive imaging (multiterritorial vascular ultrasound and coronary artery calcium score, CACS) to assess the presence, burden, and extent of SA.

RESULTS

Individuals with higher HOMA-IR values had higher rates of CVRFs. HOMA-IR showed a direct association with the multiterritorial extent of SA and CACS (p < 0.001) and with global plaque volume measured by 3-dimensional vascular ultrasound (p < 0.001). After adjusting for key CVRFs and HbA1c, HOMA-IR values ≥ 3 were associated with both the multiterritorial extent of SA (odds ratio 1.41; 95%CI: 1.01 to 1.95, p = 0.041) and CACS > 0 (odds ratio 1.74; 95%CI: 1.20 to 2.54, p = 0.004), as compared with the HOMA-IR < 2 (the reference HOMA-IR category). In a stratified analysis, this association remained significant in individuals with a low-to-moderate SCORE2 risk estimate (75.6% of the cohort) but not in high-risk individuals.

CONCLUSIONS

The use of HOMA-IR identified low-risk individuals with a higher burden of SA, after adjusting for the effects of key traditional CVRFs and HbA1c. HOMA-IR is a simple measure that could facilitate earlier implementation of primary CV prevention strategies in clinical practice.

Effects of myo-inositol vs. metformin on hormonal and metabolic parameters in women with PCOS: a meta-analysis

OBJECTIVE

Polycystic Ovary Syndrome is the most prevalent hormonal disorder in females. Over the years, metformin (MET) has become the first-line choice of treatment; however, due to its gastrointestinal side effects, a more recent drug, myo-inositol (MI), has been introduced. We aim to conduct a systematic review and meta-analysis to compare the effects of MET and MI on hormonal and metabolic parameters.

MATERIALS AND METHODS

Authors extensively searched PubMed, Scopus, Cochrane Library, Google Scholar, and Web of Science for randomized clinical trials (RCTs) until August 2021. Eight (n = 8) articles were included, with a total sample size of 1088, of which 460 patients received MET, 436 received MI, and 192 received a combination of both. Standard mean differences (SMDs) and Confidence Intervals (CIs) were used for data synthesis, and forest plots were made using Review Manager 5.4 for Statistical Analysis using the random-effect model.

RESULTS

The meta-analysis indicates that there is no significant difference between MET and MI in terms of their effects on BMI (SMD = 0.16, 95% CI: - 0.11 to 0.43, p = 0.24), fasting insulin (SMD = 0.00, 95% CI: - 0.26 to 0.27, p = 0.97), fasting blood sugar (SMD = 0.11, 95% CI: - 0.31to 0.53, p = 0.60), HOMA index (SMD = 0.09, 95% CI: - 0.20 to 0.39, p = 0.50), and LH/FSH (SMD = 0.20, 95% CI: - 0.24 to 0.64, p = 0.37). BMI, fasting blood sugar, and LH/FSH ratio reported moderate heterogeneity because of the varying number of study participants.

CONCLUSION

Our meta-analysis comparing hormonal and metabolic parameters between MET and MI did not show much significant difference, indicating both drugs are equally beneficial in improving metabolic and hormonal parameters in patients with PCOS.

The Role of Cdc42 in the Insulin and Leptin Pathways Contributing to the Development of Age-Related Obesity

Age-related obesity significantly increases the risk of chronic diseases such as type 2 diabetes, cardiovascular diseases, hypertension, and certain cancers. The insulin-leptin axis is crucial in understanding metabolic disturbances associated with age-related obesity. Rho GTPase Cdc42 is a member of the Rho family of GTPases that participates in many cellular processes including, but not limited to, regulation of actin cytoskeleton, vesicle trafficking, cell polarity, morphology, proliferation, motility, and migration. Cdc42 functions as an integral part of regulating insulin secretion and aging. Some novel roles for Cdc42 have also been recently identified in maintaining glucose metabolism, where Cdc42 is involved in controlling blood glucose levels in metabolically active tissues, including skeletal muscle, adipose tissue, pancreas, etc., which puts this protein in line with other critical regulators of glucose metabolism. Importantly, Cdc42 plays a vital role in cellular processes associated with the insulin and leptin signaling pathways, which are integral elements involved in obesity development if misregulated. Additionally, a change in Cdc42 activity may affect senescence, thus contributing to disorders associated with aging. This review explores the complex relationships among age-associated obesity, the insulin-leptin axis, and the Cdc42 signaling pathway. This article sheds light on the vast molecular web that supports metabolic dysregulation in aging people. In addition, it also discusses the potential therapeutic implications of the Cdc42 pathway to mitigate obesity since some new data suggest that inhibition of Cdc42 using antidiabetic drugs or antioxidants may promote weight loss in overweight or obese patients.

Xanthohumol alleviates palmitate-induced inflammation and prevents osteoarthritis progression by attenuating mitochondria dysfunction/NLRP3 inflammasome axis

Osteoarthritis (OA) is a prevalent chronic degenerative joint disease worldwide. Obesity has been linked to OA, and increased free fatty acid levels (e.g., palmitate) contribute to inflammatory responses and cartilage degradation. Xanthohumol (Xn), a bioactive prenylated chalcone, was shown to exhibit antioxidative, anti-inflammatory, and anti-obesity capacities in multiple diseases. However, a clear description of the preventive effects of Xn on obesity-associated OA is unavailable. This study aimed to assess the chondroprotective function of Xn on obesity-related OA. The in vitro levels of inflammatory and ECM matrix markers in human chondrocytes were assessed after the chondrocytes were treated with PA and Xn. Additionally, in vivo cartilage degeneration was assessed following oral administration of HFD and Xn. This study found that Xn treatment completely reduces the inflammation and extracellular matrix degradation caused by PA. The proposed mechanism involves AMPK signaling pathway activation by Xn, which increases mitochondrial biogenesis, attenuates mitochondrial dysfunction, and inhibits NLRP3 inflammasome and the NF-κB signaling pathway induced by PA. In summary, this study highlights that Xn could decrease inflammation reactions and the degradation of the cartilage matrix induced by PA by inhibiting the NLRP3 inflammasome and attenuating mitochondria dysfunction in human chondrocytes.

Metabolite profiles of diabetes mellitus and response to intervention in anti-hyperglycemic drugs

Type 2 diabetes mellitus (T2DM) has become a major health problem, threatening the quality of life of nearly 500 million patients worldwide. As a typical multifactorial metabolic disease, T2DM involves the changes and interactions of various metabolic pathways such as carbohydrates, amino acid, and lipids. It has been suggested that metabolites are not only the endpoints of upstream biochemical processes, but also play a critical role as regulators of disease progression. For example, excess free fatty acids can lead to reduced glucose utilization in skeletal muscle and induce insulin resistance; metabolism disorder of branched-chain amino acids contributes to the accumulation of toxic metabolic intermediates, and promotes the dysfunction of β-cell mitochondria, stress signal transduction, and apoptosis. In this paper, we discuss the role of metabolites in the pathogenesis of T2DM and their potential as biomarkers. Finally, we list the effects of anti-hyperglycemic drugs on serum/plasma metabolic profiles.

Effect of high-intensity interval training compared to moderate-intensity continuous training on body composition and insulin sensitivity in overweight and obese adults: A systematic review and meta-analysis

Objective

To compare the effects of high-intensity interval training (HIIT) and moderate-intensity continuous training (MICT) on adults with overweight and obesity. Outcomes, including changes in insulin sensitivity, weight, body mass index (BMI), waist circumference, and body fat, were analyzed.

Methods

A systematic literature review was conducted. This review is registered in the International Prospective Register of Systematic Reviews (PROSPERO) under the number CRD42021281899. Clinical trials involving individuals who are overweight and obese and comparing HIIT with MICT effects on insulin sensitivity, weight, BMI, body fat percentage, and waist circumference were included. PubMed, Web of Science, Embase, and Scopus databases were searched using controlled vocabulary and free-text terms related to HIIT, obesity, and overweight. The search included studies published until September 2022. The Rob2 tool was used to assess the risk of bias. The results were presented through meta-analyses that provided summary estimators and confidence intervals. Subgroup analyses were conducted to assess the effect of the risk of bias on the outcomes. This research did not receive any specific funding.

Results

Of the 2534 articles, 30 met the eligibility criteria. The intervention duration ranged from 4 to 16 weeks. The observed effects for each outcome were as follows: insulin sensitivity (p = 0.02), weight (p = 0.58), BMI (p = 0.53), waist circumference (p = 0.87), body fat percentage (p = 0.07), body fat mass in kilograms (p = 0.39). The level of evidence obtained was moderate except for waist circumference, which was rated as low. Limitations included heterogeneity in training protocols, measurements, and study duration. Additionally, a risk of bias was identified in these studies.

Conclusion

HIIT and MICT did not significantly differ in their effects on weight, BMI, waist circumference, or body fat mass in adults with overweight and obesity. However, a moderate beneficial effect of HIIT was observed on insulin sensitivity. Therefore, further evidence is required to confirm these findings.

GPCR-mediated effects of fatty acids and bile acids on glucose homeostasis

Fatty acids and glucose are key biomolecules that share several commonalities including serving as energy substrates and as signaling molecules. Fatty acids can be synthesized endogenously from intermediates of glucose catabolism via de-novo lipogenesis. Bile acids are synthesized endogenously in the liver from the biologically important lipid molecule, cholesterol. Evidence abounds that fatty acids and bile acids play direct and indirect roles in systemic glucose homeostasis. The tight control of plasma glucose levels during postprandial and fasted states is principally mediated by two pancreatic hormones, insulin and glucagon. Here, we summarize experimental studies on the endocrine effects of fatty acids and bile acids, with emphasis on their ability to regulate the release of key hormones that regulate glucose metabolism. We categorize the heterogenous family of fatty acids into short chain fatty acids (SCFAs), unsaturated, and saturated fatty acids, and highlight that along with bile acids, these biomolecules regulate glucose homeostasis by serving as endogenous ligands for specific G-protein coupled receptors (GPCRs). Activation of these GPCRs affects the release of incretin hormones by enteroendocrine cells and/or the secretion of insulin, glucagon, and somatostatin by pancreatic islets, all of which regulate systemic glucose homeostasis. We deduce that signaling induced by fatty acids and bile acids is necessary to maintain euglycemia to prevent metabolic diseases such as type-2 diabetes and related metabolic disorders.

Therapeutic Activity of Green Tea Epigallocatechin-3-Gallate on Metabolic Diseases and Non-Alcoholic Fatty Liver Diseases: The Current Updates

Green tea polyphenols have numerous functions including antioxidation and modulation of various cellular proteins and are thus beneficial against metabolic diseases including obesity, type 2 diabetes, cardiovascular and non-alcoholic fatty liver diseases, and their comorbidities. Epigallocatechin-3-gallate (EGCG) is the most abundant polyphenol in green tea and is attributed to antioxidant and free radical scavenging activities, and the likelihood of targeting multiple metabolic pathways. It has been shown to exhibit anti-obesity, anti-inflammatory, anti-diabetic, anti-arteriosclerotic, and weight-reducing effects in humans. Worldwide, the incidences of metabolic diseases have been escalating across all age groups in modern society. Therefore, EGCG is being increasingly investigated to address the problems. This review presents the current updates on the effects of EGCG on metabolic diseases, and highlights evidence related to its safety. Collectively, this review brings more evidence for therapeutic application and further studies on EGCG and its derivatives to alleviate metabolic diseases and non-alcoholic fatty liver diseases.

Liver insulinization as a driver of triglyceride dysmetabolism

Metabolic dysfunction-associated fatty liver disease (MAFLD) is an increasingly prevalent fellow traveller with the insulin resistance that underlies type 2 diabetes mellitus. However, the mechanistic connection between MAFLD and impaired insulin action remains unclear. In this Perspective, we review data from humans to elucidate insulin's aetiological role in MAFLD. We focus particularly on the relative preservation of insulin's stimulation of triglyceride (TG) biosynthesis despite its waning ability to curb hepatic glucose production (HGP). To explain this apparent 'selective insulin resistance', we propose that hepatocellular processes that lead to TG accumulation require less insulin signal transduction, or 'insulinization,' than do those that regulate HGP. As such, mounting hyperinsulinaemia that barely compensates for aberrant HGP in insulin-resistant states more than suffices to maintain hepatic TG biosynthesis. Thus, even modestly elevated or context-inappropriate insulin levels, when sustained day and night within a heavily pro-lipogenic metabolic milieu, may translate into substantial cumulative TG biosynthesis in the insulin-resistant state.

Innovative Therapeutic Approaches in Non-Alcoholic Fatty Liver Disease: When Knowing Your Patient Is Key

Non-alcoholic fatty liver disease (NAFLD) encompasses a spectrum of disorders ranging from simple steatosis to non-alcoholic steatohepatitis (NASH). Hepatic steatosis may result from the dysfunction of multiple pathways and thus multiple molecular triggers involved in the disease have been described. The development of NASH entails the activation of inflammatory and fibrotic processes. Furthermore, NAFLD is also strongly associated with several extra-hepatic comorbidities, i.e., metabolic syndrome, type 2 diabetes mellitus, obesity, hypertension, cardiovascular disease and chronic kidney disease. Due to the heterogeneity of NAFLD presentations and the multifactorial etiology of the disease, clinical trials for NAFLD treatment are testing a wide range of interventions and drugs, with little success. Here, we propose a narrative review of the different phenotypic characteristics of NAFLD patients, whose disease may be triggered by different agents and driven along different pathophysiological pathways. Thus, correct phenotyping of NAFLD patients and personalized treatment is an innovative therapeutic approach that may lead to better therapeutic outcomes.

Effect of Manual Lymphatic Drainage on the Concentrations of Selected Adipokines, Cytokines, C-Reactive Protein and Parameters of Carbohydrate and Lipid Metabolism in Patients with Abnormal Body Mass Index: Focus on Markers of Obesity and Insulin Resistance

The aim of the study was to assess the impact of manual lymphatic drainage (MLD) on the parameters of carbohydrate metabolism, lipid metabolism and the level of selected adipokines and cytokines in people with abnormal body mass index (BMI). In addition, an attempt was made to assess the optimal cut-off values of serum concentrations of the biochemical parameters studied in identifying the risk of obesity and insulin resistance (IR). The study included 60 subjects who underwent 10 and 30 min long MLD sessions three times a week. The study group included 15 patients with a normal body mass index (group I; n = 15), overweight patients (group II; n = 15) and obese patients (group III; n = 10). The control group was IV; n = 20 subjects not undergoing MLD. Biochemical tests were carried out on all subjects at stage 0' (before MLD therapy) and at stage 1' (one month after MLD therapy). In the control group, the time between the sample collection at stage 0' and stage 1' was the same as in the study group. Our results showed that 10 MLD sessions may have a positive effect on the selected biochemical parameters, including insulin, 2h-PG, leptin and HOMA-IR values in normal weight and overweight patients. In addition, in the study group, the highest AUC_ROC values in identifying the risk of obesity were found for leptin (AUC_ROC = 82.79%; cut-off = 17.7 ng/mL; p = 0.00004), insulin (AUC_ROC = 81.51%; cut-off = 9.5 µIU/mL; p = 0.00009) and C-peptide (AUC_ROC = 80.68%; cut-off = 2.3 ng/mL; p = 0.0001) concentrations as well as for HOMA-IR values (AUC_ROC = 79.97%; cut-off = 1.8; p = 0.0002). When considering the risk of IR, we observed the highest diagnostic value for insulin (AUC_ROC = 93.05%; cut-off = 1.8 ng/mL; p = 0.053), which was followed by C-peptide (AUC_ROC = 89.35%; cut-off = 17.7 ng/mL; p = 0.000001), leptin (AUC_ROC = 79.76%; cut-off = 17.6 ng/mL; p = 0.0002) and total cholesterol (AUC_ROC = 77.31%; cut-off = 198 mg/dL; p = 0.0008). Our results indicate that MLD may have a positive effect on selected biochemical parameters, including insulin, 2h-PG, leptin and HOMA-IR, in normal weight and overweight patients. In addition, we successfully established optimal cut-off values for leptin in the assessment of obesity and insulin in the assessment of insulin resistance in patients with abnormal body mass index. Based on our findings, we hypothesize that MLD, when combined with caloric restriction and physical activity, may serve as an effective preventive intervention against the development of obesity and insulin resistance.

Metabolic Syndrome and Its Association with Nonalcoholic Steatohepatitis

The relationship between insulin resistance, metabolic syndrome (MetS), and nonalcoholic fatty liver disease (NAFLD) is complicated. Although insulin resistance is almost universal in people with NAFLD and MetS, NAFLD may be present without features of MetS and vice versa. While NAFLD has a strong correlation with cardiometabolic risk factors, these are not intrinsic components of this condition. Taken together, our knowledge gaps call for caution regarding the common assertion that NAFLD is the hepatic manifestation of the MetS, and for defining NAFLD in broad terms as a "metabolic dysfunction" based on a diverse and poorly understood constellation of cardiometabolic features.

Feasibility of high-dose tadalafil and effects on insulin resistance in well-controlled patients with type 2 diabetes (MAKROTAD): a single-centre, double-blind, randomised, placebo-controlled, cross-over phase 2 trial

Background

Phosphodiesterase-5 inhibitors exert positive vascular and metabolic effects in type 2 diabetes (T2D), but the effect on insulin resistance in T2D is unclear.

Methods

This randomised, double blind, placebo-controlled, two-period crossover trial was conducted at Sahlgrenska University Hospital (Gothenburg, Sweden). Men without apparent erectile dysfunction (age 40-70 years) and women (age 55-70 years, post-menopause) diagnosed with T2D between 3 months and 10 years, haemoglobin A1c (HbA1c) < 60 mmol/mol and a body mass index (BMI) 27-40 kg/m² were enrolled. Participants were randomly assigned to one period of oral tadalafil 20 mg once a day and one period of placebo for 6 weeks, separated by an 8-week wash-out period. Placebo and tadalafil tablets were made visually indistinguishable and delivered randomized in two separate boxes for each participant. Both treatment periods ended with a glucose clamp, and measurements of body composition and metabolic markers in blood, subcutaneous and muscular interstitial fluid. The primary aim was to assess difference in whole-body insulin resistance after 6-weeks of treatment, determined after completion of the two study arms, and secondary aims were to study effects of tadalafil on pathophysiology of T2D as well as tolerability of high-dose tadalafil in T2D. Primary analysis was performed in participants with full analysis set (FAS) and safety analysis in all participants who received at least one dose of study medication. This trial is registered with ClinicalTrials.gov (NCT02601989), and EudraCT (2015-000573).

Findings

Between January 22nd, 2016, and January 31st, 2019, 23 participants with T2D were enrolled, of whom 18 were included in the full analysis set. The effect of tadalafil on insulin resistance was neutral compared with placebo. However, tadalafil decreased glycaemia measured as HbA1c (mean difference -2.50 mmol/mol, 95% confidence interval (CI), -4.20; -0.78, p = 0.005), and, further, we observed amelioration of endothelial function and markers of liver steatosis and glycolysis, whereas no statistically significant differences of other clinical phenotyping were shown. Muscle pain, dyspepsia, and headache were more frequent in participants on high-dose tadalafil compared with placebo (p < 0.05) but no difference between treatments appeared for serious adverse events.

Interpretation

High-dose tadalafil does not decrease whole-body insulin resistance, but increases microcirculation, induces positive effects in the liver and in intermediate metabolites, in parallel with an improved metabolic control measured as HbA1c. High-dose tadalafil is moderately well tolerated, warranting larger trials to define the optimal treatment regimen in T2D.

Funding

The Swedish Research Council, Swedish Diabetes Foundation, Novo Nordisk Foundation, the Swedish state under the agreement between the Swedish government and the county councils, the ALF-agreement, Sahlgrenska University Hospital funds, Gothenburg Society of Medicine, Eli Lilly & Company, USA, and Eli Lilly & Company, Sweden AB.

Transcriptomic Analysis from Normal Glucose Tolerance to T2D of Obese Individuals Using Bioinformatic Tools

Understanding the role of white adipose tissue (WAT) in the occurrence and progression of metabolic syndrome is of considerable interest; among the metabolic syndromes are obesity and type 2 diabetes (T2D). Insulin resistance is a key factor in the development of T2D. When the target cells become resistant to insulin, the pancreas responds by producing more insulin to try to lower blood glucose. Over time, this can lead to a state of hyperinsulinemia (high levels of insulin in the blood), which can further exacerbate insulin resistance and contribute to the development of T2D. In order to understand the difference between healthy and unhealthy obese individuals, we have used published transcriptomic profiling to compare differences between the WAT obtained from obese diabetics and subjects who are obese with normal glucose tolerance and insulin resistance. The identification of aberrantly expressed messenger RNA (mRNA) and the resulting molecular interactions and signaling networks is essential for a better understanding of the progression from normal glucose-tolerant obese individuals to obese diabetics. Computational analyses using Ingenuity Pathway Analysis (IPA) identified multiple activated signaling networks in obesity progression from insulin-resistant and normal glucose-tolerant (IR-NGT) individuals to those with T2D. The pathways affected are: Tumor Necrosis Factor (TNF), Extracellular signal-Regulated protein Kinase 1/2 ERK1/2, Interleukin 1 A (IL1A), Protein kinase C (Pkcs), Convertase C5, Vascular endothelial growth factor (Vegf), REL-associated protein (RELA), Interleukin1/1 B (IL1/1B), Triggering receptor expressed on myeloid cells (TREM1) and Nuclear factor KB1 (NFKB1) networks, while functional annotation highlighted Liver X Receptor (LXR) activation, phagosome formation, tumor microenvironment pathway, LPS/IL-1 mediated inhibition of RXR function, TREM1 signaling and IL-6 signaling. Together, by conducting a thorough bioinformatics study of protein-coding RNAs, prospective targets could be exploited to clarify the molecular pathways underlying the development of obesity-related type 2 diabetes.

The role of exercise in obesity-related cancers: Current evidence and biological mechanisms

Cancer ranks among the five leading causes of death in almost all countries and has important repercussions for individual and public health, the healthcare system, and society in general. Obesity increases the incidence of many types of cancer, but growing evidence suggests that physical activity may decrease risk for developing a variety of obesity-related cancer types, and, in some cases, may improve cancer prognosis and mortality rates. This review summarizes recent evidence on the effect of physical activity on obesity-related cancer prevention and survival. For some cancers, including breast, colorectal, and endometrial cancer, there is strong evidence for a preventative effect of exercise, but for many others, including gallbladder and kidney cancer, and multiple myeloma, evidence is inconsistent or largely lacking. Though many potential mechanisms have been proposed to explain the onco-protective effect of exercise, including improved insulin sensitivity, alterations in sex hormone availability, improved immune function and inflammation, myokine secretion, and modulation of intracellular signaling at the level of AMP kinase, the exact mechanism(s) of action within each cancer subtype remains poorly defined. Overall, a deeper understanding of how exercise can help against cancer and of the exercise parameters that can be altered to optimize exercise prescription is necessary and should be the subject of future investigation.

Fatty acids as a direct regulator of aldosterone hypersecretion

Primary hyperaldosteronism is a major cause of secondary hypertension and carries additional cardiovascular risks beyond that of the elevated blood pressure. Primary hyperaldosteronism is more prevalent in obese people, and weight loss reduces aldosterone levels. It needs to be determined whether obesity related factors directly contribute to the pathogenesis of primary hyperaldosteronism. Here we show that the non-esterified fatty acids (NEFA) palmitic acid, and to a lesser extent, linoleic acid significantly stimulated aldosterone production and steroid enzyme induction in adrenocortical HAC15 cells of human origin. Palmitic acid, linoleic acid, and to a much lesser extent, oleic acid induced the expression of aldosterone synthase. Induction of the Steroidogenic Acute Regulatory Protein (StAR) was modest. Increased aldosterone secretion was independent of fatty acid beta-oxidation in the mitochondria but may involve free fatty acid receptor 1 (FFAR1/GPR40) and endoplasmic reticulum (ER) stress. Palmitic acid and linoleic acid induced the expression of C/EBP Homologous Protein (CHOP), a marker of ER stress, correlating with their ability to induce aldosterone synthase gene expression. Palmitic acid, but not linoleic acid decreased mitochondrial potentials and induced uncoupling protein 2 (UCP2). Palmitic acid enhanced, while docosahexaenoic acid (DHA) suppressed aldosterone response to angiotensin II (Ang-II). Our study provides evidence that NEFAs modulate aldosterone production, and further suggests that hyperaldosteronism shares similar pathogenesis with other obesity-related disorders such as metabolic syndrome.

Modeling the progression of Type 2 diabetes with underlying obesity

Environmentally induced or epigenetic-related beta-cell dysfunction and insulin resistance play a critical role in the progression to diabetes. We developed a mathematical modeling framework capable of studying the progression to diabetes incorporating various diabetogenic factors. Considering the heightened risk of beta-cell defects induced by obesity, we focused on the obesity-diabetes model to further investigate the influence of obesity on beta-cell function and glucose regulation. The model characterizes individualized glucose and insulin dynamics over the span of a lifetime. We then fit the model to the longitudinal data of the Pima Indian population, which captures both the fluctuations and long-term trends of glucose levels. As predicted, controlling or eradicating the obesity-related factor can alleviate, postpone, or even reverse diabetes. Furthermore, our results reveal that distinct abnormalities of beta-cell function and levels of insulin resistance among individuals contribute to different risks of diabetes. This study may encourage precise interventions to prevent diabetes and facilitate individualized patient treatment.

Are Women with Normal-Weight Obesity at Higher Risk for Cardiometabolic Disorders?

OBJECTIVES

This study aimed to evaluate the cardiometabolic abnormalities in women with normal-weight obesity (NWO) in comparison with lean, overweight, and obese women.

METHODS

This cross-sectional study evaluated the assessment of cardiometabolic abnormalities of women with NWO compared to lean, overweight, and obese women. NWO was defined as a BMI < 25 kg.m^-2 and a BFP higher than 30%. Anthropometric variables, cardiometabolic abnormality markers (fasting blood glucose (FBG), blood pressure (BP), lipid profile, insulin resistance, and high-sensitivity C-reactive protein (hs-CRP)), and liver enzymes were also examined.

RESULTS

Significant differences were observed in HDL concentrations between NWO, lean, and obese participants (p < 0.05). There were no significant differences in FBG, insulin resistance, liver enzymes, or cholesterol between groups (p > 0.05). The prevalence of the abnormal metabolic phenotype was higher in NWO compared to the lean group (4.0% and 24.1%, respectively; p < 0.05). Women with type 2 and 3 obesity had abnormal metabolic profiles (60.9% and 73.9%, respectively) compared to NWO participants (p < 0.01). The NWO group had a significantly higher incidence of cardiometabolic abnormalities compared to the lean participants (p < 0.05), while the type 2 and 3 obese individuals had significantly higher incidences compared to the NWO group (p < 0.001 and p < 0.001, respectively).

CONCLUSIONS

Individuals with NWO had a significantly higher incidence of cardiometabolic abnormalities when compared to lean participants. These abnormalities strongly relate to BFP and waist circumferences.

Disease progression promotes changes in adipose tissue signatures in type 2 diabetic (db/db) mice: The potential pathophysiological role of batokines

Unlike the white adipose tissue (WAT) which mainly stores excess energy as fat, brown adipose tissue (BAT) has become physiologically important and therapeutically relevant for its prominent role in regulating energy metabolism. The current study makes use of an established animal model of type 2 diabetes (T2D) db/db mice to determine the effect of the disease progression on adipose tissue morphology and gene regulatory signatures. Results showed that WAT and BAT from db/db mice display a hypertrophied phenotype that is consistent with increased expression of the pro-inflammatory cytokine, tumor necrosis factor-alpha (Tnf-α). Moreover, BAT from both db/db and non-diabetic db/+ control mice displayed an age-related impairment in glucose homeostasis, inflammatory profile, and thermogenic regulation, as demonstrated by reduced expression of genes like glucose transporter (Glut-4), adiponectin (AdipoQ), and uncoupling protein 1 (Ucp-1). Importantly, gene expression of the batokines regulating sympathetic neurite outgrowth and vascularization, including bone morphogenic protein 8b (Bmp8b), fibroblast growth factor 21 (Fgf-21), neuregulin 4 (Nrg-4) were altered in BAT from db/db mice. Likewise, gene expression of meteorin-like (Metrnl), growth differentiation factor 15 (Gdt-15), and C-X-C motif chemokine-14 (Cxcl-14) regulating pro- and anti-inflammation were altered. This data provides some new insights into the pathophysiological mechanisms involved in BAT hypertrophy (or whitening) and the disturbances of batokines during the development and progression of T2D. However, these are only preliminary results as additional experiments are necessary to confirm these findings in other experimental models of T2D.

Hypoxia as a Double-Edged Sword to Combat Obesity and Comorbidities

The global epidemic of obesity is tightly associated with numerous comorbidities, such as type II diabetes, cardiovascular diseases and the metabolic syndrome. Among the key features of obesity, some studies have suggested the abnormal expansion of adipose-tissue-induced local endogenous hypoxic, while other studies indicated endogenous hyperoxia as the opposite trend. Endogenous hypoxic aggravates dysfunction in adipose tissue and stimulates secretion of inflammatory molecules, which contribute to obesity. In contrast, hypoxic exposure combined with training effectively generate exogenous hypoxic to reduce body weight and downregulate metabolic risks. The (patho)physiological effects in adipose tissue are distinct from those of endogenous hypoxic. We critically assess the latest advances on the molecular mediators of endogenous hypoxic that regulate the dysfunction in adipose tissue. Subsequently we propose potential therapeutic targets in adipose tissues and the small molecules that may reverse the detrimental effect of local endogenous hypoxic. More importantly, we discuss alterations of metabolic pathways in adipose tissue and the metabolic benefits brought by hypoxic exercise. In terms of therapeutic intervention, numerous approaches have been developed to treat obesity, nevertheless durability and safety remain the major concern. Thus, a combination of the therapies that suppress endogenous hypoxic with exercise plans that augment exogenous hypoxic may accelerate the development of more effective and durable medications to treat obesity and comorbidities.

The Cognitive Improvement and Alleviation of Brain Hypermetabolism Caused by FFAR3 Ablation in Tg2576 Mice Is Persistent under Diet-Induced Obesity

Obesity and aging are becoming increasingly prevalent across the globe. It has been established that aging is the major risk factor for Alzheimer’s disease (AD), and it is becoming increasingly evident that obesity and the associated insulin resistance are also notably relevant risk factors. The biological plausibility of the link between high adiposity, insulin resistance, and dementia is central for understanding AD etiology, and to form bases for prevention efforts to decrease the disease burden. Several studies have demonstrated a strong association between short chain fatty acid receptor FFAR3 and insulin sensitivity. Interestingly, it has been recently established that FFAR3 mRNA levels are increased in early stages of the AD pathology, indicating that FFAR3 could play a key role in AD onset and progression. Indeed, in the present study we demonstrate that the ablation of the Ffar3 gene in Tg2576 mice prevents the development of cognitive deficiencies in advanced stages of the disease. Notably, this cognitive improvement is also maintained upon a severe metabolic challenge such as the exposure to high-fat diet (HFD) feeding. Moreover, FFAR3 deletion restores the brain hypermetabolism displayed by Tg2576 mice. Collectively, these data postulate FFAR3 as a potential novel target for AD.

Galectin-1 in Obesity and Type 2 Diabetes

Galectin-1 is a carbohydrate-binding protein expressed in many tissues. In recent years, increasing evidence has emerged for the role of galectin-1 in obesity, insulin resistance and type 2 diabetes. Galectin-1 has been highly conserved through evolution and is involved in key cellular functions such as tissue maturation and homeostasis. It has been shown that galectin-1 increases in obesity, both in the circulation and in the adipose tissue of human and animal models. Several proteomic studies have independently identified an increased galectin-1 expression in the adipose tissue in obesity and in insulin resistance. Large population-based cohorts have demonstrated associations for circulating galectin-1 and markers of insulin resistance and incident type 2 diabetes. Furthermore, galectin-1 is associated with key metabolic pathways including glucose and lipid metabolism, as well as insulin signalling and inflammation. Intervention studies in animal models alter animal weight and metabolic profile. Several studies have also linked galectin-1 to the progression of complications in diabetes, including kidney disease and retinopathy. Here, we review the current knowledge on the clinical potential of galectin-1 in obesity and type 2 diabetes.

Obesity in pregnancy is a predictor of persistent subclinical myocardial dysfunction over postpartum period

PURPOSE

No previous study provided a complete functional evaluation of all cardiac chambers in pregnant women with obesity. Moreover, the impact of cardiovascular changes associated with obesity in pregnancy on maternal outcome is unclear.

METHODS

46 consecutive pregnant women with obesity, defined by body mass index (BMI) ≥ 30 Kg/m2, and 83 age- (35.5 ± 4.1 vs. 34.1 ± 5.1 yrs, p = 0.11), ethnicity- (caucasian 65.2 vs. 66.3%, p = 0.90) and gestational week-matched (36.3 ± 1.7 vs. 36.5 ± 1.5 wks, p = 0.49) pregnant women without obesity (BMI < 30 Kg/m2) were examined in the first trimester (12-14 weeks), third trimester (36-38 weeks) and 6-10 weeks postpartum. All women underwent obstetric visit, blood tests and transthoracic echocardiography implemented with two-dimensional speckle tracking echocardiography analysis of biventricular and biatrial myocardial deformation indices at the three time points. Outcome was persistent subclinical myocardial dysfunction, defined as an absolute value of left ventricular global longitudinal strain (LV-GLS) less negative than - 20%, in postpartum.

RESULTS

Despite normal biventricular systolic function, all myocardial strain indices were significantly lower in pregnant women with obesity than controls. At 8.2 ± 2.2 weeks postpartum, LV-GLS remained less negative than - 20% in 86.9% of women with obesity in pregnancy. Maternal age (OR 1.68, 95%CI 1.14-2.48), third trimester BMI (OR 7.17, 95%CI 1.77-28.9) and third trimester neutrophil-to-lymphocyte ratio (NLR) (OR 1.75, 95%CI 1.22-2.51) were independently associated with outcome. Maternal age ≥ 35 years, BMI ≥ 30 Kg/m2 and NLR ≥ 5.5 were the optimal cut-off values for predicting persistent subclinical myocardial dysfunction in postpartum.

CONCLUSIONS

Pregnant women with obesity, age ≥ 35 yrs and low chronic inflammation have significantly increased risk of persistent subclinical myocardial dysfunction over postpartum.

Dietary carbohydrates: Pathogenesis and potential therapeutic targets to obesity-associated metabolic syndrome

Metabolic syndrome (MetS) is a common feature in obesity, comprising a cluster of abnormalities including abdominal fat accumulation, hyperglycemia, hyperinsulinemia, dyslipidemia, and hypertension, leading to diabetes and cardiovascular diseases (CVD). Intake of carbohydrates (CHO), particularly a sugary diet that rapidly increases blood glucose, triglycerides, and blood pressure levels is the predominant determining factor of MetS. Complex CHO, on the other hand, are a stable source of energy taking a longer time to digest. In particular, resistant starch (RS) or soluble fiber is an excellent source of prebiotics, which alter the gut microbial composition, which in turn improves metabolic control. Altering maternal CHO intake during pregnancy may result in the child developing MetS. Furthermore, lifestyle factors such as physical inactivity in combination with dietary habits may synergistically influence gene expression by modulating genetic and epigenetic regulators transforming childhood obesity into adolescent metabolic disorders. This review summarizes the common pathophysiology of MetS in connection with the nature of CHO, intrauterine nutrition, genetic predisposition, lifestyle factors, and advanced treatment approaches; it also emphasizes how dietary CHO may act as a key element in the pathogenesis and future therapeutic targets of obesity and MetS.

The role of the platelet pool of Plasminogen Activator Inhibitor-1 in well-controlled type 2 diabetes patients

Background

The main inhibitor of the fibrinolytic system, Plasminogen Activator Inhibitor -1 (PAI-1), irreversibly binds tissue-type Plasminogen Activator (t-PA) and thereby inhibits the protective action of tPA against thrombus formation. Elevated levels of plasma PAI-1 are associated with an increased risk of cardiovascular events and are observed in subjects with type 2 diabetes (T2D) and obesity. Platelets contain the majority of PAI-1 present in blood and exhibit the ability to synthesis active PAI-1. Diabetic platelets are known to be hyper-reactive and larger in size; however, whether these features affect their contribution to the elevated levels of plasma PAI-1 in T2D is not established.

Objectives

To characterize the PAI-1 antigen content and the mRNA expression in platelets from T2D subjects compared to obese and lean control subjects, in order to elucidate the role of platelet PAI-1 in T2D.

Methods

Nine subjects with T2D and obesity were recruited from Primary Care Centers together with 15 healthy control subjects (8 lean subjects and 7 with obesity). PAI-1 antigen levels in plasma, serum and platelets were determined by ELISA, and PAI-1 mRNA expression was analyzed by qPCR.

Results

There was no significant difference in PAI-1 mRNA expression or PAI-1 antigen in platelets in T2D subject in comparison to obese and lean control subjects. An elevated level of plasma PAI-1 was seen in both T2D and obese subjects. PAI-1 gene expression was significantly higher in both obese groups compared to lean.

Conclusion

Similar levels of protein and mRNA expression of PAI-1 in platelets from T2D, obese and lean subjects indicate a limited role of platelets for the elevated plasma PAI-1 levels. However, an increased synthesis rate of mRNA transcripts in platelets from T2D and an increased release of PAI-1 could also result in similar mRNA and protein levels. Hence, synthesis and release rates of PAI-1 from platelets in T2D and obesity need to be investigated to further elucidate the role of platelets in obesity and T2D.

Associations of body mass index, fasting insulin, and inflammation with mortality: a prospective cohort study

BACKGROUND/OBJECTIVES

Obesity is often considered to increase the risk for premature mortality. Higher fasting insulin and c-reactive protein are associated with higher body mass index (BMI) and all-cause mortality, so may confound the association between obesity and mortality. Our objective was to determine the independent associations between BMI, fasting insulin, c-reactive protein, and all-cause mortality in a general population sample.

METHODS

This prospective cohort study included non-institutionalized US adults (≥20 years) from the National Health and Nutrition Examination Surveys 1999-2000 to 2013-2014. The main exposures of interest were BMI, fasting insulin, c-reactive protein. Mortality data were obtained through linking participants to the National Death Index (ending December 31, 2015).

RESULTS

There were 12,563 participants with a median age of 45 years (range 20-85) and 47.9% were male. The median BMI was 27 kg/m² (IQR 24-32), median fasting insulin was 54 pmol/L (IQR 35-87), and median c-reactive protein was 1.9 mg/L (IQR 0.8-4.4). In a Cox model adjusted for age, biological sex, cigarette smoking, and ten chronic conditions, higher BMI parameterized with quadratic and linear terms was not associated with mortality. When fasting insulin and the natural logarithm of c-reactive protein were included in the model, an inverse association between BMI and mortality was present (compared to the referent category of 5th percentile: 1st percentile, HR 1.10, 95% CI 1.06-1.13; 99th percentile, HR 0.48, 95% CI 0.34-0.69). In contrast, higher levels of fasting insulin and c-reactive protein were associated with an increased risk of mortality (for fasting insulin: 1st percentile, HR 0.98, 95% CI 0.97-0.99; 99th percentile, HR 1.83, 95% CI 1.48-2.26; for c-reactive protein, 1st percentile, HR 0.87, 95% CI 0.84-0.90; 99th percentile, HR 2.77, 95% CI 2.12-3.62).

CONCLUSIONS

Higher fasting insulin and higher c-reactive protein confound the association between BMI and the risk of all-cause mortality. The increase in mortality that has been attributed to higher BMI is more likely due to hyperinsulinemia and inflammation rather than obesity.

Association Between Insulin Resistance and Cardiovascular Disease Risk Varies According to Glucose Tolerance Status: A Nationwide Prospective Cohort Study

OBJECTIVE

To investigate whether the association between insulin resistance and cardiovascular disease (CVD) differs by glucose tolerance status.

RESEARCH DESIGN AND METHODS

We analyzed a nationwide sample of 111,576 adults without CVD at baseline, using data from the China Cardiometabolic Disease and Cancer Cohort Study. Insulin resistance was estimated by sex-specific HOMA of insulin resistance (HOMA-IR) quartiles for participants with normal glucose tolerance, prediabetes, or diabetes, separately, and by 1 SD of HOMA-IR for the overall study participants. We used Cox proportional hazards models to examine the association between insulin resistance and incident CVD according to glucose tolerance status and evaluate the CVD risk associated with the combined categories of insulin resistance and obesity in prediabetes and diabetes, as compared with normal glucose tolerance. Models were adjusted for age, sex, education attainment, alcohol drinking, smoking, physical activity, and diet quality.

RESULTS

In participants with normal glucose tolerance, prediabetes, and diabetes defined by three glucose parameters, multivariable-adjusted hazard ratios (95% CIs) for incident CVD associated with the highest versus the lowest quartile of HOMA-IR were 1.03 (0.82-1.30), 1.23 (1.07-1.42), and 1.61 (1.30-2.00), respectively; the corresponding values for CVD per 1-SD increase in HOMA-IR were 1.04 (0.92-1.18), 1.12 (1.06-1.18), and 1.15 (1.09-1.21), respectively (P for interaction = 0.011). Compared with participants with normal glucose tolerance, in participants with prediabetes, the combination of the highest HOMA-IR quartile and obesity showed 17% (95% CI 2-34%) higher risk of CVD, while the combination of the lowest two HOMA-IR quartiles and nonobesity showed 15-17% lower risk of CVD. In participants with diabetes, the upper two HOMA-IR quartiles exhibited 44-77% higher risk of CVD, regardless of obesity status. Consistent findings were observed for glucose tolerance status defined by different combinations of glycemic parameters.

CONCLUSIONS

Glucose intolerance status exacerbated the association between insulin resistance and CVD risk. Compared with adults with normal glucose tolerance, adults with prediabetes who were both insulin resistant and obese exhibited higher risks of CVD, while in adults with diabetes, the CVD risk related to insulin resistance remained, regardless of obesity.

The effect of aerobic exercise on the lipophagy of adipose tissue in obese male mice

This article explores the obesity state and the changes in the level of lipophagy in adipose tissue after exercise to lose weight, so as to provide direction and basis for theoretical research on obesity prevention and control. We established a high-fat diet model of obese mice, and applied exercise intervention and intraperitoneal injection of chloroquine to inhibit autophagy. Long-term high-fat diet can cause obesity in mice, and the process of lipophagy is inhibited, which may be one of the reasons for fat accumulation. Eight weeks of aerobic exercise can effectively reduce the weight of obese mice and promote lipolysis; this process is mainly completed by lipase decomposition, in addition to require the participation of the lipophagy process.

Preoperative Oral Carbohydrate Levels in Patients with Type 2 Diabetes Mellitus: The Clinical Guiding Significance of Free Fatty Acids

Background

It is still controversial whether preoperative oral carbohydrate (POC) should be applied to patients with type 2 diabetes mellitus (T2DM) in the enhanced recovery after surgery (ERAS) protocol. There is no relevant consensus or indicators to provide guidance as to whether T2DM patients should take POC.

Methods

In total, 164 T2DM patients who underwent laparoscopic hepatectomy were analyzed. According to the level of blood free fatty acids (FFAs) and whether the patients received POC, the patients were divided into 6 groups: the low FFA carbohydrate group (LFFAC group), low FFA fasting water group (LFFAF group), medium FFA carbohydrate group (MFFAC group), medium FFA fasting water group (MFFAF group), high FFA carbohydrate group (HFFAC group) and high FFA fasting water group (HFFAF group).

Results

Patients with low FFA levels showed better perioperative blood glucose control and a lower incidence of postoperative complications than those in the medium and high FFA groups, especially when patients received POC. Further analyses revealed that the postoperative plasma concentrations of IL-6 and TNF-α were significantly decreased in the POC group compared with the fasting water group, except for patients with high FFA levels. Receiver operating characteristic (ROC) curve analysis revealed that when the FFA concentration was higher than 0.745 mmol/L, the risk of poor blood glucose control during the perioperative period was increased.

Conclusions

FFAs have clinical guiding significance for the application of POC in patients with T2DM under ERAS administration. T2DM patients with low FFAs are more suitable for receiving POC.

Anti-adipogenic activity of maackiain and ononin is mediated via inhibition of PPARγ in human adipocytes

Obesity is a global health burden for which we do not yet have effective treatments for prevention or therapy. Plants are an invaluable source of bioactive leads possessing anti-adipogenic potential. Ethnopharmacological use of Ononis spinosa L. roots (OSR) for treatment of obesity and metabolic disorders requires а scientific rationale. The current study examined the anti-adipogenic capacity of OSR and its secondary metabolites ononin (ONON) and maackiain (MACK) in human adipocytes as an in vitro model of obesity. Both ONON and MACK diminished lipid accumulation during adipocyte differentiation. Molecular docking analysis exposed the potential interactions between MACK or ONON and target regulatory adipogenic proteins. Furthermore, results from an RT-qPCR analysis disclosed significant upregulation of AMPK by MACK and ONON treatment. In addition, ONON increased SIRT1, PI3K and ACC mRNA expression, while MACK notably downregulated CEBPA, AKT, SREBP1, ACC and ADIPOQ. The protein level of PI3K, C/EBPα, PPARγ and adiponectin was reduced upon MACK treatment in a concentration-dependent manner. Similarly, ONON suppressed PI3K, PPARγ and adiponectin protein abundance. Finally, our study provides evidence that ONON exerts anti-adipogenic effect by upregulation of SIRT1 and inhibition of PI3K, PPARγ and adiponectin, while MACK induced strong inhibitory effect on adipogenesis via hampering PI3K, PPARγ/C/EBPα signaling and anti-lipogenic effect through downregulation of SREBP1 and ACC. Even though OSR does not hamper adipogenic differentiation, it could be exploited as a source of natural leads with anti-adipogenic potential. The multidirectional mechanism of action of MACK warrant further validation in the context of in vivo obesity models.

The contribution of avoidable factors in doubling or halving the odds of hypertension

Background

Despite the well-known impact of fruit/vegetable consumption, physical activity, body mass index, waist-hip ratio, fasting blood glucose, and total cholesterol on blood pressure, the amount of exposure to these factors is required to halve or double the odds of hypertension is unknown, but it was investigated in this research.

Methods

The data used in this study are derived from results of the seventh Iranian national STEPS survey involving 30,542 adults aged 18 years or older. The questionnaire measured non-communicable disease risk factors covered three different levels including behavioral characteristics, physical and biochemical measurements. The level of exposure to factors necessary to reach the odds ratio of 0.5 or odds ratio of 2.0 was obtained from the coefficients of the multiple logistic regression model.

Results

An OR of 0.5 corresponds to 7 servings of fruit and vegetable consumption daily and burning of 7175 kcal through physical activity at work or recreation daily. An OR of 2.0 corresponds to an increase in body mass index of about 11 kg/m², an increase in the waist-hip ratio of about 18%, an increase in fasting blood glucose of about 77 mg/dl, and an increase in total cholesterol of about 134 mg/dl.

Conclusion

The results of this study indicate how much fruit and vegetable and physical activity halve the odds of hypertension and how much increase in body mass index, the waist-hip ratio, fasting blood glucose, and total cholesterol can double the odds of hypertension. Such information may be useful for developing guidelines by policymakers.

How exposure to chronic stress contributes to the development of type 2 diabetes: A complexity science approach

Chronic stress contributes to the onset of type 2 diabetes (T2D), yet the underlying etiological mechanisms are not fully understood. Responses to stress are influenced by earlier experiences, sex, emotions and cognition, and involve a complex network of neurotransmitters and hormones, that affect multiple biological systems. In addition, the systems activated by stress can be altered by behavioral, metabolic and environmental factors. The impact of stress on metabolic health can thus be considered an emergent process, involving different types of interactions between multiple variables, that are driven by non-linear dynamics at different spatiotemporal scales. To obtain a more comprehensive picture of the links between chronic stress and T2D, we followed a complexity science approach to build a causal loop diagram (CLD) connecting the various mediators and processes involved in stress responses relevant for T2D pathogenesis. This CLD could help develop novel computational models and formulate new hypotheses regarding disease etiology.

Altered Plasma Fatty Acid Abundance Is Associated with Cachexia in Treatment-Naïve Pancreatic Cancer

Cachexia occurs in up to 80% of pancreatic ductal adenocarcinoma (PDAC) patients and is characterized by unintentional weight loss and tissue wasting. To understand the metabolic changes that occur in PDAC-associated cachexia, we compared the abundance of plasma fatty acids (FAs), measured by gas chromatography, of subjects with treatment-naïve metastatic PDAC with or without cachexia, defined as a loss of > 2% weight and evidence of sarcopenia (n = 43). The abundance of saturated, monounsaturated, and polyunsaturated FAs was not different between subjects with cachexia and those without. Oleic acid was significantly higher in subjects with cachexia (p = 0.0007) and diabetes (p = 0.015). Lauric (r = 0.592, p = 0.0096) and eicosapentaenoic (r = 0.564, p = 0.015) acids were positively correlated with age in cachexia patients. Subjects with diabetes (p = 0.021) or both diabetes and cachexia (p = 0.092) had low palmitic:oleic acid ratios. Linoleic acid was lower in subjects with diabetes (p = 0.018) and correlated with hemoglobin (r = 0.519, p = 0.033) and albumin (r = 0.577, p = 0.015) in subjects with cachexia. Oleic or linoleic acid may be useful treatment targets or biomarkers of cachexia in patients with metastatic PDAC, particularly those with diabetes.

Significance of Postprandial Insulin and Triglycerides to Evaluate the Metabolic Response of Composite Meals Differing in Nutrient Composition – A Randomized Cross-Over Trial

Background and aims

GlucoTRIG, based on postprandial plasma insulin and triglyceride concentrations, has been recently developed as a novel index to determine the postprandial metabolic response to the meals. This study aimed to test GlucoTRIG as a measure for ranking composite meals for their metabolic effects.

Methods

In a randomized cross-over trial, healthy adult volunteers (both males and females; n = 10 for each meal) consumed three is caloric (2000 kj) test meals (meal 1, meal 2, meal 3) of varying macronutrient composition. Postmeal consumption, venous blood samples were collected to determine plasma insulin and plasma triglycerides for estimating the GlucoTRIG value using (Triglycerides_180min × Insulin_180min) - (Triglycerides_0min × Insulin_0min).

Results

The GlucoTRIG values differed significantly (p = 0.0085) across meals. The statistical significance remains even after adjusting for confounding variables such as baseline diet, insulin, and triglycerides. The meal (M3) with a high fiber, low total fat content and containing less refined foods (fruits, beans, vegetables, plain yogurt) exhibited a significantly (p = 0.007) lower GlucoTRIG value (10 ± 7.7) compared to the other two meals, M1 (77 ± 19.8) and M2 (38 ± 12.1) which contained low processed foods, and were relatively high in fat and low in fiber meals. No statistically significant differences were observed between M1 and M2 meal.

Conclusions

GlucoTRIG is a physiologically based index that may be useful to rank composite meals for reducing the risk of metabolic diseases. Further research focusing on the application of GlucoTRIG to foods, meals, and diets is warranted.

ACTRN12619000973112 (Australian New Zealand Clinical Trials Registry, ANZCTR).

Pathophysiological Mechanisms in Non-Alcoholic Fatty Liver Disease: From Drivers to Targets

Non-alcoholic fatty liver disease (NAFLD) is characterized by the excessive and detrimental accumulation of liver fat as a result of high-caloric intake and/or cellular and molecular abnormalities. The prevalence of this pathological event is increasing worldwide, and is intimately associated with obesity and type 2 diabetes mellitus, among other comorbidities. To date, only therapeutic strategies based on lifestyle changes have exhibited a beneficial impact on patients with NAFLD, but unfortunately this approach is often difficult to implement, and shows poor long-term adherence. For this reason, great efforts are being made to elucidate and integrate the underlying pathological molecular mechanism, and to identify novel and promising druggable targets for therapy. In this regard, a large number of clinical trials testing different potential compounds have been performed, albeit with no conclusive results yet. Importantly, many other clinical trials are currently underway with results expected in the near future. Here, we summarize the key aspects of NAFLD pathogenesis and therapeutic targets in this frequent disorder, highlighting the most recent advances in the field and future research directions.

Subcutaneous Adipose Tissue Metabolic Function and Insulin Sensitivity in People With Obesity

We used stable isotope-labeled glucose and palmitate tracer infusions, a hyperinsulinemic-euglycemic clamp, positron emission tomography of muscles and adipose tissue after [18F]fluorodeoxyglucose and [15O]water injections, and subcutaneous adipose tissue (SAT) biopsy to test the hypotheses that 1) increased glucose uptake in SAT is responsible for high insulin-stimulated whole-body glucose uptake in people with obesity who are insulin sensitive and 2) putative SAT factors thought to cause insulin resistance are present in people with obesity who are insulin resistant but not in those who are insulin sensitive. We found that high insulin-stimulated whole-body glucose uptake in insulin-sensitive participants with obesity was not due to channeling of glucose into SAT but, rather, was due to high insulin-stimulated muscle glucose uptake. Furthermore, insulin-stimulated muscle glucose uptake was not different between insulin-sensitive obese and lean participants even though adipocytes were larger, SAT perfusion and oxygenation were lower, and markers of SAT inflammation, fatty acid appearance in plasma in relation to fat-free mass, and plasma fatty acid concentration were higher in the insulin-sensitive obese than in lean participants. In addition, we observed only marginal or no differences in adipocyte size, SAT perfusion and oxygenation, and markers of SAT inflammation between insulin-resistant and insulin-sensitive obese participants. Plasma fatty acid concentration was also not different between insulin-sensitive and insulin-resistant obese participants, even though SAT was resistant to the inhibitory effect of insulin on lipolysis in the insulin-resistant obese group. These data suggest that several putative SAT factors commonly implicated in causing insulin resistance are normal consequences of SAT expansion unrelated to insulin resistance.

Obesity-An Update on the Basic Pathophysiology and Review of Recent Therapeutic Advances

Obesity represents a major public health problem with a prevalence increasing at an alarming rate worldwide. Continuous intensive efforts to elucidate the complex pathophysiology and improve clinical management have led to a better understanding of biomolecules like gut hormones, antagonists of orexigenic signals, stimulants of fat utilization, and/or inhibitors of fat absorption. In this article, we will review the pathophysiology and pharmacotherapy of obesity including intersection points to the new generation of antidiabetic drugs. We provide insight into the effectiveness of currently approved anti-obesity drugs and other therapeutic avenues that can be explored.