Adipose tissue IL-6 content correlates with resistance to insulin activation of glucose uptake both in vivo and in vitro

A Comprehensive Pilot Study to Elucidate the Distinct Gut Microbial Composition and Its Functional Significance in Cardio-Metabolic Disease

Cardio-metabolic disease is a significant global health challenge with increasing prevalence. Recent research underscores the disruption of gut microbial balance as a key factor in disease susceptibility. We aimed to characterize the gut microbiota composition and function in cardio-metabolic disease and healthy controls. For this purpose, we collected stool samples of 18 subjects (12 diseased, 6 healthy) and we performed metagenomics analysis and functional prediction using QIIME2 and PICRUSt. Furthermore, we carried out assessments of microbe-gene interactions, gene ontology, and microbe-disease associations. Our findings revealed distinct microbial patterns in the diseased group, particularly evident in lower taxonomic levels with significant variations in 14 microbial features. The diseased cohort exhibited an enrichment of Lachnospiraceae family, correlating with obesity, insulin resistance, and metabolic disturbances. Conversely, reduced levels of Clostridium, Gemmiger, and Ruminococcus genera indicated a potential inflammatory state, linked to compromised butyrate production and gut permeability. Functional analyses highlighted dysregulated pathways in amino acid metabolism and energy equilibrium, with perturbations correlating with elevated branch-chain amino acid levels-a known contributor to insulin resistance and type 2 diabetes. These findings were consistent across biomarker assessments, microbe-gene associations, and gene ontology analyses, emphasizing the intricate interplay between gut microbial dysbiosis and cardio-metabolic disease progression. In conclusion, our study unveils significant shifts in gut microbial composition and function in cardio-metabolic disease, emphasizing the broader implications of microbial dysregulation. Addressing gut microbial balance emerges as a crucial therapeutic target in managing cardio-metabolic disease burden.

Comparative analyses of anti-inflammatory effects of Resveratrol, Pterostilbene and Curcumin: in-silico and in-vitro evidences

Inflammation is an adaptive response that involves activation, and recruitment of cells of innate and adaptive immune cells for restoring homeostasis. To safeguard the host from the threat of inflammatory agents, microbial invasion, or damage, the immune system activates the transcription factor NF-κB and produces cytokines such as TNF-α, IL- 6, IL-1β, and α. Sirtuin 1 (SIRT1) controls the increased amounts of proinflammatory cytokines, which in turn controls inflammation. Three phytoconstituents resveratrol (RES), pterostilbene (PTE), and curcumin (CUR) which are SIRT1- activators and that have marked anti-inflammatory effects (in-vivo), were chosen for the current study. These compounds were compared for their anti-inflammatory potential by in-silico docking studies for IL-6, TNF-α, NF-κB, and SIRT1 and in-vitro THP-1 cell line studies for IL-6, TNF-α. PTE was found to be more effective than RES and CUR in lowering the concentrations of IL-6 and TNF-α in THP-1 cell line studies, and it also showed a favorable docking profile with cytokines and SIRT1. Thus, PTE appears to be a better choice for further research and development as a drug or functional food supplement with the ability to reduce inflammation in metabolic disorders.

Graphical abstract

Schematic representation of in-silico and in-vitro analysis of Resveratrol, Pterostilbene, and Curcumin.

L-Ergothioneine slows the progression of age-related hearing loss in CBA/CaJ mice

The naturally occurring amino acid, l-ergothioneine (EGT), has immense potential as a therapeutic, having shown promise in the treatment of other disease models, including neurological disorders. EGT is naturally uptaken into cells via its specific receptor, OCTN1, to be utilized by cells as an antioxidant and anti-inflammatory. In our current study, EGT was administered over a period of 6 months to 25-26-month-old CBA/CaJ mice as a possible treatment for age-related hearing loss (ARHL), since presbycusis has been linked to higher levels of cochlear oxidative stress, apoptosis, and chronic inflammation. Results from the current study indicate that EGT can prevent aging declines of some key features of ARHL. However, we found a distinct sex difference for the response to the treatments, for hearing - Auditory Brainstem Responses (ABRs) and Distortion Product Otoacoustic Emissions (DPOAEs). Males exhibited lower threshold declines in both low dose (LD) and high dose (HD) test groups throughout the testing period and did not display some of the characteristic aging declines in hearing seen in Control animals. In contrast, female mice did not show any therapeutic effects with either treatment dose. Further confirming this sex difference, EGT levels in whole blood sampling throughout the testing period showed greater uptake of EGT in males compared to females. Additionally, RT-PCR results from three tissue types of the inner ear confirmed EGT activity in the cochlea in both males and females. Males and females exhibited significant differences in biomarkers related to apoptosis (Cas-3), inflammation (TNF-a), oxidative stress (SOD2), and mitochondrial health (PGC1a).These changes were more prominent in males as compared to females, especially in stria vascularis tissue. Taken together, these findings suggest that EGT has the potential to be a naturally derived therapeutic for slowing down the progression of ARHL, and possibly other neurodegenerative diseases. EGT, while effective in the treatment of some features of presbycusis in aging males, could also be modified into a general prophylaxis for other age-related disorders where treatment protocols would include eating a larger proportion of EGT-rich foods or supplements. Lastly, the sex difference discovered here, needs further investigation to see if therapeutic conditions can be developed where aging females show better responsiveness to EGT.

Impact of visceral adipose tissue on longevity and metabolic health: a comparative study of gene expression in perirenal and epididymal fat of Ames dwarf mice

Emerging research underscores the pivotal role of adipose tissue in regulating systemic aging processes, particularly when viewed through the lens of the endocrine hypotheses of aging. This study delves into the unique adipose characteristics in an important animal model of aging - the long-lived Ames dwarf (df/df) mice. Characterized by a Prop1df gene mutation, these mice exhibit a deficiency in growth hormone (GH), prolactin, and TSH, alongside extremely low circulating IGF-1 levels. Intriguingly, while surgical removal of visceral fat (VFR) enhances insulin sensitivity in normal mice, it paradoxically increases insulin resistance in Ames dwarfs. This suggests an altered profile of factors produced in visceral fat in the absence of GH, indicating a unique interplay between adipose tissue function and hormonal influences in these models. Our aim was to analyze the gene expression related to lipid and glucose metabolism, insulin pathways, inflammation, thermoregulation, mitochondrial biogenesis, and epigenetic regulation in the visceral (perirenal and epididymal) adipose tissue of Ames dwarf and normal mice. Our findings reveal an upregulation in the expression of key genes such as Lpl, Adrβ3, Rstn, Foxo1, Foxo3a, Irs1, Cfd, Aldh2, Il6, Tnfα, Pgc1α, Ucp2, and Ezh2 in perirenal and Akt1, Foxo3a, PI3k, Ir, Acly, Il6, Ring1a, and Ring 1b in epididymal fat in df/df mice. These results suggest that the longevity phenotype in Ames dwarfs, which is determined by peripubertal GH/IGF-1 levels, may also involve epigenetic reprogramming of adipose tissue influenced by hormonal changes. The increased expression of genes involved in metabolic regulation, tumor suppression, mitochondrial biogenesis, and insulin pathways in Ames dwarf mice highlights potentially beneficial aspects of this model, opening new avenues for understanding the molecular underpinnings of longevity and aging.

Overexpression of Plg-RKT protects against adipose dysfunction and dysregulation of glucose homeostasis in diet-induced obese mice

The plasminogen receptor, Plg-RKT, is a unique cell surface receptor that is broadly expressed in cells and tissues throughout the body. Plg-RKT localizes plasminogen on cell surfaces and promotes its activation to the broad-spectrum serine protease, plasmin. In this study, we show that overexpression of Plg-RKT protects mice from high fat diet (HFD)-induced adipose and metabolic dysfunction. During the first 10 weeks on the HFD, the body weights of mice that overexpressed Plg-RKT (Plg-RKT-OEX) were lower than those of control mice (CagRosaPlgRKT). After 10 weeks on the HFD, CagRosaPlgRKT and Plg-RKT-OEX mice had similar body weights. However, Plg-RKT-OEX mice showed a more metabolically favourable body composition phenotype. Plg-RKT-OEX mice also showed improved glucose tolerance and increased insulin sensitivity. We found that the improved metabolic functions of Plg-RKT-OEX mice were mechanistically associated with increased energy expenditure and activity, decreased proinflammatory adipose macrophages and decreased inflammation, elevated brown fat thermogenesis, and higher expression of adipose PPARγ and adiponectin. These findings suggest that Plg-RKT signalling promotes healthy adipose function via multiple mechanisms to defend against obesity-associated adverse metabolic phenotypes.

Biochemical and Structural Characterization of OvoATh2: A Mononuclear Nonheme Iron Enzyme from Hydrogenimonas thermophila for Ovothiol Biosynthesis

Ovothiol A and ergothioneine are thiol-histidine derivatives with sulfur substitutions at the δ-carbon or ε-carbon of the l-histidine imidazole ring, respectively. Both ovothiol A and ergothioneine have protective effects on many aging-related diseases, and the sulfur substitution plays a key role in determining their chemical and biological properties, while factors governing sulfur incorporation regioselectivities in ovothiol and ergothioneine biosynthesis in the corresponding enzymes (OvoA, Egt1, or EgtB) are not yet known. In this study, we have successfully obtained the first OvoA crystal structure, which provides critical information to explain their C-S bond formation regioselectivity. Furthermore, OvoATh2 exhibits several additional activities: (1) ergothioneine sulfoxide synthase activity akin to Egt1 in ergothioneine biosynthesis; (2) cysteine dioxygenase activity using l-cysteine and l-histidine analogues as substrates; (3) cysteine dioxygenase activity upon mutation of an active site tyrosine residue (Y406). The structural insights and diverse chemistries demonstrated by OvoATh2 pave the way for future comprehensive structure-function correlation studies.

Interleukin-6 in Traumatic Brain Injury: A Janus-Faced Player in Damage and Repair

Traumatic brain injury (TBI) is a common and often devastating illness, with wide-ranging public health implications. In addition to the primary injury, victims of TBI are at risk for secondary neurological injury by numerous mechanisms. Current treatments are limited and do not target the profound immune response associated with injury. This immune response reflects a convergence of peripheral and central nervous system-resident immune cells whose interaction is mediated in part by a disruption in the blood-brain barrier (BBB). The diverse family of cytokines helps to govern this communication and among these, Interleukin (IL)-6 is a notable player in the immune response to acute neurological injury. It is also a well-established pharmacological target in a variety of other disease contexts. In TBI, elevated IL-6 levels are associated with worse outcomes, but the role of IL-6 in response to injury is double-edged. IL-6 promotes neurogenesis and wound healing in animal models of TBI, but it may also contribute to disruptions in the BBB and the progression of cerebral edema. Here, we review IL-6 biology in the context of TBI, with an eye to clarifying its controversial role and understanding its potential as a target for modulating the immune response in this disease.

Exploration of natural flavones' bioactivity and bioavailability in chronic inflammation induced-type-2 diabetes mellitus

Diabetes, being the most widespread illness, poses a serious threat to global public health. It seems that inflammation plays a critical role in the pathophysiology of diabetes. This review aims to demonstrate a probable link between type 2 diabetes mellitus (T2DM) and chronic inflammation during its development. Additionally, the current review examined the bioactivity of natural flavones and the possible molecular mechanisms by which they influence diabetes and inflammation. While natural flavones possess remarkable anti-diabetic and anti-inflammatory bioactivities, their therapeutic use is limited by the low oral bioavailability. Several factors contribute to the low bioavailability, including poor water solubility, food interaction, and unsatisfied metabolic behaviors, while the diseases (diabetes, inflammation, etc.) causing even less bioavailability. Throughout the years, different strategies have been developed to boost flavones' bioavailability, including structural alteration, biological transformation, and innovative drug delivery system design. This review addresses current advancements in improving the bioavailability of flavonoids in general, and flavones in particular. Clinical trials were also analyzed to provide insight into the potential application of flavonoids in diabetes and inflammatory therapies.

Differential Roles of Interleukin-6 in Severe Acute Respiratory Syndrome-Coronavirus-2 Infection and Cardiometabolic Diseases

Severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) infection can lead to a cytokine storm, unleashed in part by pyroptosis of virus-infected macrophages and monocytes. Interleukin-6 (IL-6) has emerged as a key participant in this ominous complication of COVID-19. IL-6 antagonists have improved outcomes in patients with COVID-19 in some, but not all, studies. IL-6 signaling involves at least 3 distinct pathways, including classic-signaling, trans-signaling, and trans-presentation depending on the localization of IL-6 receptor and its binding partner glycoprotein gp130. IL-6 has become a therapeutic target in COVID-19, cardiovascular diseases, and other inflammatory conditions. However, the efficacy of inhibition of IL-6 signaling in metabolic diseases, such as obesity and diabetes, may depend in part on cell type-dependent actions of IL-6 in controlling lipid metabolism, glucose uptake, and insulin sensitivity owing to complexities that remain to be elucidated. The present review sought to summarize and discuss the current understanding of how and whether targeting IL-6 signaling ameliorates outcomes following SARS-CoV-2 infection and associated clinical complications, focusing predominantly on metabolic and cardiovascular diseases.

High-fat diet-induced dopaminergic dysregulation induces REM sleep fragmentation and ADHD-like behaviors

Consumption of a high-fat diet (HFD) has been associated with reduced wakefulness and various behavioral deficits, including anxiety, depression, and anhedonia. The dopaminergic system, which plays a crucial role in sleep and ADHD, is known to be vulnerable to chronic HFD. However, the association between HFD-induced behavioral and molecular changes remains unclear. Therefore, we investigated the effects of a HFD on the dopaminergic system and its association with behavioral deficits in male mice. The mice were divided into normal diet and HFD groups and were analyzed for sleep patterns, behavior tests, and transcription levels of dopamine-related genes in the brain. The HFD group showed decreased wakefulness, increased REM sleep with fragmented patterns, decreased time spent in the center zone of the open field test, shorter immobile time in the tail suspension test, impaired visuospatial memory, and reduced sucrose preference. Additionally, the HFD group had decreased mRNA levels of D1R, COMT, and DAT in the nucleus accumbens, which negatively correlated with REM sleep proportion and REM sleep bout count. The results suggest that HFD-induced behavioral deficits were resemblance to ADHD-like behavioral phenotypes and disturbs REM sleep by dysregulating the dopaminergic system.

Functional role of skeletal muscle-derived interleukin-6 and its effects on lipid metabolism

The detrimental impact of obesity on human health is increasingly evident with the rise in obesity-related diseases. Skeletal muscle, the crucial organ responsible for energy balance metabolism, plays a significant role as a secretory organ by releasing various myokines. Among these myokines, interleukin 6 (IL-6) is closely associated with skeletal muscle contraction. IL-6 triggers the process of lipolysis by mobilizing energy-storing adipose tissue, thereby providing energy for physical exercise. This phenomenon also elucidates the health benefits of regular exercise. However, skeletal muscle and adipose tissue maintain a constant interaction, both directly and indirectly. Direct interaction occurs through the accumulation of excess fat within skeletal muscle, known as ectopic fat deposition. Indirect interaction takes place when adipose tissue is mobilized to supply the energy for skeletal muscle during exercise. Consequently, maintaining a functional balance between skeletal muscle and adipose tissue becomes paramount in regulating energy metabolism and promoting overall health. IL-6, as a representative cytokine, participates in various inflammatory responses, including non-classical inflammatory responses such as adipogenesis. Skeletal muscle influences adipogenesis through paracrine mechanisms, primarily by secreting IL-6. In this research paper, we aim to review the role of skeletal muscle-derived IL-6 in lipid metabolism and other physiological activities, such as insulin resistance and glucose tolerance. By doing so, we provide valuable insights into the regulatory function of skeletal muscle-derived myokines in lipid metabolism.

Underlying biochemical effects of intermittent fasting, exercise and honey on streptozotocin-induced liver damage in rats

Purpose

Derangements of liver transcriptional factors and enzymes have important implications in diabetes-induced related complications. Hence, this study which consists of two experimental phases was aimed at evaluating the possible underlying molecular mechanisms of intermittent fasting (IF), exercise starvation and honey in streptozotocin (STZ)-mediated liver damage in diabetic rats.

Methods

The diabetic rats were treated orally with distilled water (0.5 ml/kg), IF, starvation and honey at 1 g/kg body weight in the non-diabetic phase for four (4) weeks. After STZ injections, four (4) weeks of IF, exercise, starvation, and honey therapy were used as interventions prior to a biochemical evaluation of the liver.

Results

IF and exercise greatly decreased liver transcription factor (resistin, SREBP-1c), inflammatory cytokines/enzyme (TNF-α, IL-6, IL-1ß, MPO) as well as oxidative and nitrergic stress with correspondence increased liver PPAR-γ, IL-10, SOD, CAT and GSH in diabetic rats unlike starvation and honey regimen relative to diabetic controls. Furthermore, IF and exercise significantly improved hepatic glycogen synthase and decreased glycogen phosphorylase in diabetic rats compared to the diabetic control group, but starvation and honey therapy had no such influence. IF and exercise strategically reduces STZ-induced liver metabolic disorder via through modulation of liver transcriptional factors and inhibition of pro-inflammatory cytokines, oxido-nitrergic and adipokine signaling pathway.

Role of HOMA-IR and IL-6 as screening markers for the metabolic syndrome in patients with chronic schizophrenia: a psychiatric hospital-based cross-sectional study

This study starts from the metabolic related indexes and cellular inflammatory factors in patients with chronic schizophrenia to find out that it can be used as an effective screening index of metabolic syndrome. 320 patients with chronic schizophrenia (course of disease > 5 years) and 165 healthy subjects were selected. The mental symptoms of the patients were measured by positive and negative syndrome scale. Blood samples from patients and healthy controls were collected to detect blood glucose, triglyceride, HDL and fasting insulin. The serum levels of IL-1β, IL-2, IL-6, IL-17, IFN-γ and TNF-α were determined repeatedly by sandwich enzyme-linked immunosorbent assay. The levels of HOMA-IR, plasma inflammatory factors IL-2, IL-6, IL-17 and TNF-α in patient group were higher than those in healthy group. It was found that there were differences in age and related metabolic indexes between patients with chronic schizophrenia with and without metabolic syndrome. In addition, HOMA-IR, plasma cytokines IL-2 and IL-6 still showed differences between groups. In the Spearmen correlation analysis of insulin resistance index, cytokines and metabolic indexes, it was found that there was a significant correlation between HOMA-IR, IL-6 and related metabolic indexes and metabolic syndrome. ROC curve analysis showed that HOMAIR and IL-6 could be used as screening indexes for MS in male and female patients with schizophrenia.Metabolic syndrome is an important risk factor for cardiovascular disease in patients with chronic schizophrenia. HOMA-IR and IL-6 can be used as effective biological indicators to screen MS in patients with chronic schizophrenia.

The impact of sports on the normal functioning of the prostate gland: A review

This article explores the relationship of physical activity to the normal functioning of the prostate gland. The biomechanism of hormonal activity during exercise was studied, and special attention was paid to the biomechanism of an actively working muscle and the release of myokines. The analysis of the relationship between myokines and the functioning of the prostate gland was carried out. It has been established that physical activity reduces the risk of developing prostate diseases and is an important method of prevention.

A Possible Modulator of Vitiligo Metabolic Impairment: Rethinking a PPARγ Agonist

Vitiligo is a complex disease wherein derangements in multiple pathways determine the loss of functional melanocytes. Since its pathogenesis is not yet completely understood, vitiligo lacks a definitive safe and efficacious treatment. At present, different therapies are available; however, each modality has its baggage of disadvantages and side effects. Recently we have described several metabolic abnormalities in cells from pigmented skin of vitiligo patients, including alterations of glucose metabolism. Therefore, we conducted a study to evaluate the effect of Pioglitazone (PGZ), a Peroxisome proliferator-activated receptor-γ (PPARγ) agonist, on cells from pigmented vitiligo skin. We treated vitiligo melanocytes and fibroblasts with low doses of PGZ and evaluated the effects on mitochondrial alterations, previously reported by our and other groups. Treatment with PGZ significantly increased mRNA and protein levels of several anaerobic glycolytic enzymes, without increasing glucose consumption. The PGZ administration fully restored the metabolic network, replacing mitochondrial membrane potential and mitochondrial DNA (mtDNA) copy number. These effects, together with a significant increase in ATP content and a decrease in reactive oxygen species (ROS) production, provide strong evidence of an overall improvement of mitochondria bioenergetics in vitiligo cells. Moreover, the expression of HMGB1, Hsp70, defined as a part of DAMPs, and PD-L1 were significantly reduced. In addition, PGZ likely reverts premature senescence phenotype. In summary, the results outline a novel mode of action of Pioglitazone, which may turn out to be relevant to the development of effective new vitiligo therapeutic strategies.

IL-1β and TNFα Cooperativity in Regulating IL-6 Expression in Adipocytes Depends on CREB Binding and H3K14 Acetylation

IL-6 was found to be overexpressed in the adipose tissue of obese individuals, which may cause insulin resistance. However, the regulation of IL-6 in adipocytes in obesity setting remains to be explored. Since IL-1β and TNFα are increased in obese adipose tissue and promote inflammation, we investigated whether cooperation between IL-1β and TNFα influences the production of IL-6. Our data show that IL-1β and TNFα cooperatively enhance IL-6 expression in 3T3L-1 adipocytes. Similar results were seen in human adipocytes isolated from subcutaneous and visceral fat. Although adipocytes isolated from lean and obese adipose tissues showed similar responses for production of IL-6 when incubated with IL-1β/TNFα, secretion of IL-6 was higher in adipocytes from obese tissue. TNFα treatment enhanced CREB binding at CRE locus, which was further enhanced with IL-1β, and was associated with elevated histone acetylation at CRE locus. On the other hand, IL-1β treatments mediated C/EBPβ binding to NF-IL-6 consensus, but not sufficiently to mediate significant histone acetylation. Interestingly, treatment with both stimulatory factors amplifies CREB binding and H3K14 acetylation. Furthermore, histone acetylation inhibition by anacardic acid or curcumin reduces IL-6 production. Notably, inhibition of histone deacetylase (HDAC) activity by trichostatin A (TSA) resulted in the further elevation of IL-6 expression in response to combined treatment of adipocytes with IL-1β and TNFα. In conclusion, our results show that there is an additive interaction between IL-1β and TNFα that depends on CREB binding and H3K14 acetylation, and leads to the elevation of IL-6 expression in adipocytes, providing interesting pathophysiological connection among IL-1β, TNFα, and IL-6 in settings such as obesity.

α1-Antitrypsin A treatment attenuates neutrophil elastase accumulation and enhances insulin sensitivity in adipose tissue of mice fed a high-fat diet

Neutrophils accumulate in insulin-sensitive tissues during obesity and may play a role in impairing insulin sensitivity. The major serine protease expressed by neutrophils is neutrophil elastase (NE), which is inhibited endogenously by α1-antitrypsin A (A1AT). We investigated the effect of exogenous (A1AT) treatment on diet-induced metabolic dysfunction. Male C57Bl/6j mice fed a chow or a high-fat diet (HFD) were randomized to receive intraperitoneal injections three times weekly of either Prolastin (human A1AT; 2 mg) or vehicle (PBS) for 10 wk. Prolastin treatment did not affect plasma NE concentration, body weight, glucose tolerance, or insulin sensitivity in chow-fed mice. In contrast, Prolastin treatment attenuated HFD-induced increases in plasma and white adipose tissue (WAT) NE without affecting circulatory neutrophil levels or increases in body weight. Prolastin-treated mice fed a HFD had improved insulin sensitivity, as assessed by insulin tolerance test, and this was associated with higher insulin-dependent IRS-1 (insulin receptor substrate) and Akt^Ser473 phosphorylation, and reduced inflammation markers in WAT but not liver or muscle. In 3T3-L1 adipocytes, Prolastin reversed recombinant NE-induced impairment of insulin-stimulated glucose uptake and IRS-1 phosphorylation. Furthermore, PDGF mediated p-Akt^Ser473 activation and glucose uptake (which is independent of IRS-1) was not affected by recombinant NE treatment. Collectively, our findings suggest that NE infiltration of WAT during metabolic overload contributes to insulin resistance by impairing insulin-induced IRS-1 signaling.NEW & NOTEWORTHY Neutrophils accumulate in peripheral tissues during obesity and are critical coordinators of tissue inflammatory responses. Here, we provide evidence that inhibition of the primary neutrophil protease, neutrophil elastase, with α1-antitrypsin A (A1AT) can improve insulin sensitivity and glucose homeostasis of mice fed a high-fat diet. This was attributed to improved insulin-induced IRS-1 phosphorylation in white adipose tissue and provides further support for a role of neutrophils in mediating diet-induced peripheral tissue insulin resistance.

Metabolic Comorbidities in Vitiligo: A Brief Review and Report of New Data from a Single-Center Experience

Among disorders of pigmentation, vitiligo is the most common, with an estimated prevalence between 0.5% and 1%. The disease has gathered increased attention in the most recent years, leading to a better understanding of the disease’s pathophysiology and its implications and to the development of newer therapeutic strategies. A better, more integrated approach is already in use for other chronic inflammatory dermatological diseases such as psoriasis, for which metabolic comorbidities are well-established and part of the routine clinical evaluation. The pathogenesis of these might be linked to cytokines which also play a role in vitiligo pathogenesis, such as IL-1, IL-6, TNF-α, and possibly IL-17. Following the reports of intrinsic metabolic alterations reported by our group, in this brief review, we analyze the available data on metabolic comorbidities in vitiligo, accompanied by our single-center experience. Increased awareness of the metabolic aspects of vitiligo is crucial to improving patient care.

[Myokines and adipomyokines: inflammatory mediators or unique molecules of targeted therapy for obesity?]

Skeletal muscles make up about 25% of the total mass in children and more than 40% in adults. Studies of the last twenty years have shown that along with the main functions, muscle tissue has hormonal activity. It was found that myocytes are able to release signaling molecules-myokines. They act auto-and paracrine within the muscle, and at a high level-through the systemic circulation, carrying out interactions between skeletal muscles and various organs and tissues, such as the liver, bone and adipose tissue, the brain. It is proved that the key factor in the expression of myokines is physical activity, and their level largely depends on physical fitness, the amount of skeletal muscle mass and its composition (the ratio of fast and slow fibers), on the intensity and duration of physical activity. Myokines have a wide range of physiological effects: myostatin suppresses the growth and differentiation of muscle tissue, and decorin, acting as its antagonist, promotes muscle hypertrophy. Interleukin 6 provides an energy substrate for contracting muscle fibers, fibroblast growth factor 21 activates the mechanisms of energy production during fasting and improves tissue sensitivity to insulin; irisin stimulates thermogenesis, glucose uptake by myocytes, and also contributes to an increase in bone mineral density. The study of myokines is one of the key links in understanding the mechanisms underlying obesity and metabolic complications, the consequences of a sedentary lifestyle, as well as the implementation of the action of physical activity. Taking into account the physiological effects of myokines in the body, in the future they can become therapeutic targets for the treatment of these conditions.

Inhibition of the Renin-Angiotensin System Reduces Gene Expression of Inflammatory Mediators in Adipose Tissue Independent of Energy Balance

Obesity is a growing health problem worldwide. The renin-angiotensin system (RAS) is present in adipose tissue, and evidence suggests that it is involved in both diet-induced obesity and the inflammation associated with obesity. The present experiments determined the effect of (1) different angiotensin-converting enzyme (ACE) inhibitors (captopril, perindopril, enalapril) and angiotensin receptor blockers (ARBs: telmisartan, losartan) on adiposity of mice fed a high-fat diet for 28 days (2); acute treatment with the ACE-inhibitor captopril on gene expression of inflammatory markers in mice fed a high-fat diet (HFD); and (3) short-term (2 days) and chronic (28 days) treatment of ACE-inhibition on energy expenditure (EE) and energy balance in mice fed HFD ad libitum (AL), as well as receiving HFD limited to the amount of calories eaten by controls (pair-fed (PF) group). Body weight, food intake, adiposity and plasma leptin were lower in ACE inhibitor or ARB-treated groups over 28 days compared with HFD untreated mice. Short-term treatment with captopril led to increased EE relative to the level in the PF group. After 28 days, EE was lower in both captopril-treated and PF mice compared with AL, but the effect was greater in the captopril-treated group. Adiponectin was elevated in captopril-treated mice, but not in PF mice, after both 2 and 28 days. Additionally, acute RAS blockade in HFD-fed mice reduced mRNA expression for MCP-1, IL-6, TLR4, and leptin in adipose tissue relative to values in untreated groups. These data demonstrate that ACE inhibition and angiotensin receptor blockade reduce food intake to produce weight loss and suggest that the anti-inflammatory effects of ACE inhibition may be independent of weight loss.

Diagnosis and treatment of HCV heart diseases

INTRODUCTION

Hepatitis C virus (HCV) infection is an important cause of a variety of otherwise unexplained heart diseases and myocardial injury. A high prevalence of HCV infection has been noted in patients with hypertrophic cardiomyopathy, dilated cardiomyopathy, arrhythmogenic right ventricular dysplasia/cardiomyopathy and myocarditis. Various arrhythmias, conduction disturbances and QT prolongation were also associated with HCV infection. A possible role of HCV infection in the pathogenesis of diabetes and atherosclerosis, and the role of immunogenetics of HCV cardiomyopathies is discussed. Recent studies suggest that mononuclear cells may be the major target of HCV, and clinical applications to test this new hypothesis are discussed.

AREAS COVERED

In this review, we will evaluate the evidence that HCV causes various cardiovascular diseases, and discuss on the pathogenesis of these disorders.

EXPERT OPINION

HCV is the cause of many different forms of heart disease worldwide, but their existence has not been recognized by most of cardiologists. The recognition and diagnosis are indispensable for the early treatment of these diseases. The diverse clinical manifestation of HCV infection and the presence of multiple extrahepatic disease syndromes could be explained by a new hypothesis that the target of HCV is leukocytes.

Maternal exposure to phenanthrene during gestation disturbs glucose homeostasis in adult mouse offspring

Epidemiological studies have indicated that polycyclic aromatic hydrocarbons were related to diabetes and insulin resistance. However, studies in mammals on the development of diabetes caused by polycyclic aromatic hydrocarbons are lacking. Pregnant mice were orally exposed to phenanthrene (0, 60 and 600 μg kg^-1 body weight) once every 3 days during gestation. In adult mouse offspring, in-utero phenanthrene exposure caused glucose intolerance and decreased insulin levels in females, while caused elevated fasting blood glucose and insulin levels in males. Serum resistin and interleukin-6 levels were elevated in offspring of both sexes. Serum adiponectin levels were decreased in females but increased in males. The insulin receptor signals were upregulated in the liver and downregulated in the skeletal muscle of F1 females, while they were inhibited in both tissues of F1 males. The visceral fat weight and body weight of the treated mice were not increased, suggesting that phenanthrene is not an obesogen, which is supported by the nonsignificant alteration in pparγ transcription in visceral adipose tissue. The transcription of retn in visceral adipose tissue was upregulated in both sexes, and that of adipoq was downregulated in females but upregulated in males, which were matched with the promoter methylation levels of these genes. The results indicated that phenanthrene exposure during gestation could disturb adipocytokine levels via epigenetic modification in adult offspring, and further influence glucose metabolism. These results might be helpful for understanding nonobesogenic pollutant-induced insulin resistance and preventing against diabetes without obesity.

Systemic Inflammation and COVID-19 Mortality in Patients with Major Noncommunicable Diseases: Chronic Coronary Syndromes, Diabetes and Obesity

COVID-19 is currently considered an inflammatory disease affecting the entire organism. In severe forms, an augmented inflammatory response leads to the fulminant “cytokine storm”, which may result in severe multisystemic end-organ damage. Apart from the acute inflammatory response, it seems that chronic inflammation also plays a major role in the clinical evolution of COVID-19 patients. Pre-existing inflammatory conditions, such as those associated with chronic coronary diseases, type 2 diabetes mellitus or obesity, may be associated with worse clinical outcomes in the context of COVID-19 disease. These comorbidities are reported as powerful predictors of poor outcomes and death following COVID-19 disease. Moreover, in the context of chronic coronary syndrome, the cytokine storm triggered by SARS-CoV-2 infection may favor vulnerabilization and rupture of a silent atheromatous plaque, with consequent acute coronary syndrome, leading to a sudden deterioration of the clinical condition of the patient. This review aims to present the current status of knowledge regarding the link between COVID-19 mortality, systemic inflammation and several major diseases associated with poor outcomes, such as cardiovascular diseases, diabetes and obesity.

Association of Adipose Tissue and Adipokines with Development of Obesity-Induced Liver Cancer

Obesity is rapidly dispersing all around the world and is closely associated with a high risk of metabolic diseases such as insulin resistance, dyslipidemia, and nonalcoholic fatty liver disease (NAFLD), leading to carcinogenesis, especially hepatocellular carcinoma (HCC). It results from an imbalance between food intake and energy expenditure, leading to an excessive accumulation of adipose tissue (AT). Adipocytes play a substantial role in the tumor microenvironment through the secretion of several adipokines, affecting cancer progression, metastasis, and chemoresistance via diverse signaling pathways. AT is considered an endocrine organ owing to its ability to secrete adipokines, such as leptin, adiponectin, resistin, and a plethora of inflammatory cytokines, which modulate insulin sensitivity and trigger chronic low-grade inflammation in different organs. Even though the precise mechanisms are still unfolding, it is now established that the dysregulated secretion of adipokines by AT contributes to the development of obesity-related metabolic disorders. This review focuses on several obesity-associated adipokines and their impact on obesity-related metabolic diseases, subsequent metabolic complications, and progression to HCC, as well as their role as potential therapeutic targets. The field is rapidly developing, and further research is still required to fully understand the underlying mechanisms for the metabolic actions of adipokines and their role in obesity-associated HCC.

Hyperandrogenism, Insulin Resistance, and Acanthosis Nigricans (HAIR-AN) Syndrome Reflects Adipose Tissue Dysfunction ("Adiposopathy" or "Sick Fat") in Asian Indian Girls

BACKGROUND

Whether HAIR-AN syndrome and polycystic ovarian syndrome (PCOS) are distinct entities or represent a phenotypic spectrum of the same syndrome is still unclear. HAIR-AN syndrome is characterized by high insulin resistance, obesity, and hyperinsulinemia as compared to PCOS and could represent adipose tissue dysfunction as the primary pathophysiologic trigger. This study was undertaken to study the role of adipose tissue dysfunction in HAIR-AN syndrome and PCOS using adipocytokines as surrogate markers of "adiposopathy."

MATERIALS AND METHODS

A cross-sectional observational study was conducted at a tertiary care hospital over a period of 1 year. Serum adiponectin, leptin, IL-6, and TNF-α levels were measured in 30 women with HAIR-AN syndrome and in 30 women with PCOS. Correlations between adipocytokines, inflammatory markers, serum testosterone, and serum insulin were determined. Data analysis was performed using the SPSS version 23.0 (IBM SPSS Statistics Inc., Chicago, IL, USA) software program.

RESULTS

Women with HAIR-AN syndrome had significantly higher hyperandrogenemia, hyperinsulinemia, and insulin resistance as compared to PCOS women. They also had high leptin levels and lower adiponectin levels (p < 0.001). However, the levels of inflammatory markers (TNF-α and IL-6) were similar in both the groups (p > 0.05). Serum adiponectin showed a negative correlation with HOMA-IR and testosterone levels, while leptin showed a positive correlation with both in HAIR-AN patients while no such correlation was found in the PCOS group.

CONCLUSION

The significantly raised adipocytokines in HAIR-AN syndrome patients as compared to PCOS patients indicates the primary role of adipose tissue dysfunction ("adiposopathy") in the pathogenesis of HAIR-AN syndrome while only a minor role, if any, in PCOS. Both these syndromes stand as distinct entities pathogenically with an overlapping phenotype.

Evaluation of the Genetic Association and Expressions of Notch-2 /Jagged-1 in Patients with Type 2 Diabetes Mellitus

Background

Diabetes mellitus (DM) is the world's most common cause of chronic kidney diseases (CKD), with approximately 1 in 4 adults with DM having CKD and 1 out of 10 to 20% of DM patients die from CKD.

Objective

The current study aims to investigate the correlation between Notch-2 and Jag-1expressions and specific inflammation biomarkers IL-1β and IL-6 with different stages of diabetic nephropathy.

Methods

From August 2018 to January 2019, three hundred subjects were recruited for this study. One hundred and fifty subjects were healthy and age-matched to the diabetic group and selected as a control group. Another 150 patients with an established diagnosis of type 2 diabetes (T2DM) according to the criteria of the American Diabetes Association (ADA) were also recruited. Blood specimens were eventually used to identify the expressions Notch-2 and Jagged-1 and the levels of inflammatory biomarkers IL-1β and IL-6.

Result

The current study shows a significant increase in gene expression and inflammatory biomarkers in patients with moderate and severe diabetic nephropathy compared to the control group. However, there was no significant difference between healthy control and mild diabetic nephropathy patients. This study shows a close association between the increase in the levels of inflammatory biomarkers IL-1β and IL-6 as well as the gene expressions levels of both Notch-2 and Jag-1 with human diabetic nephropathy.

Conclusion

According to our findings, we emphasize the use of Notch-2 and Jag-1 expressions and IL-1β and IL-6 levels as potential biomarkers for different stages of diabetic nephropathy.

Association between Neutrophilic Granulocyte Percentage and Diabetes Mellitus in Cushing's Syndrome Patients: A Cross-Sectional Study

BACKGROUND

Glucose metabolism is frequently impaired in patients with Cushing's syndrome (CS) due to chronic exposure to excess glucocorticoids. Inflammation plays an essential role in the pathophysiology of diabetes mellitus (DM). The present study aimed to investigate the potential associations of inflammatory blood cell parameters, including white blood cell (WBC) count, neutrophil count, neutrophilic granulocyte percentage (NEUT%), lymphocyte count (LYM), and lymphocyte proportion (LYM%), with diabetes mellitus in Cushing's syndrome patients.

MATERIALS AND METHODS

The cross-sectional study was conducted in Zhongshan Hospital of Fudan University, China. A total of 150 patients with Cushing's syndrome were retrospectively screened from 2017 to 2019. The demographic data, clinical data, and blood samples (lipids, adrenal, glucose, and inflammatory blood cell parameters) were recorded. Statistical analyses were carried out by using the SPSS software package, version 13.0.

RESULTS

In this study, the prevalence of diabetes mellitus was 38.7% in patients with Cushing's syndrome. Patients with DM had higher WBC, neutrophil, NEUT% levels than patients without DM (p < 0.05). As the NEUT% increased, a stepwise increase in glucose and glycated hemoglobin (HbA1c) level was observed. In addition, in the multivariate logistic regression, NEUT% was a significant independent risk factor for DM, regardless of gender, age, body mass index (BMI), and triglyceride and 12 midnight cortisol (12 MN cortisol) level (OR = 2.542, 95% CI 1.337-4.835, p < 0.001).

CONCLUSIONS

In conclusion, elevated NEUT% level was linked to diabetes in patients with Cushing's syndrome. The neutrophilic granulocyte percentage may be referred to as a new predictor for diabetes in Cushing's syndrome patients.

Senescence-associated β-galactosidase in subcutaneous adipose tissue associates with altered glycaemic status and truncal fat in severe obesity

AIM/HYPOTHESIS

Altered adipose tissue secretory profile contributes to insulin resistance and type 2 diabetes in obesity. Preclinical studies have identified senescent cells as a cellular source of proinflammatory factors in adipose tissue of obese mice. In humans, potential links with obesity comorbidities are poorly defined. Here, we investigated adipose tissue senescent status and relationships with metabolic complications in human obesity.

METHODS

The study includes a prospective cohort of 227 individuals with severe obesity. A photometric method was used to quantify senescence-associated β-galactosidase (SA-β-gal) activity in paired subcutaneous and omental adipose tissue biopsies obtained during gastric surgery. Gene and secretory profiling was performed in adipose tissue biopsies and in human primary pre-adipocytes in the presence or absence of senolytic drugs targeting senescent cells. Participants were phenotyped for anthropometric and bioclinical variables, metabolic complications and gastric surgery-induced improvement to address relationships with adipose tissue SA-β-gal.

RESULTS

SA-β-gal activity was sevenfold higher in subcutaneous than in omental adipose tissue and not associated with BMI or chronological age. Several factors, including insulin-like growth factor binding protein 3 (IGFBP3), plasminogen activator inhibitor 1 (PAI1), C-C motif chemokine ligand 2 (CCL2) and IL-6, were upregulated in subcutaneous adipose tissue in relation with SA-β-gal (p for linear trend across tertiles <0.05) and in pre-adipocytes cultured with inflammatory macrophage conditioned media. Senolytic treatment reduced SA-β-gal staining and normalised these alterations. In the whole population, subcutaneous adipose tissue SA-β-gal activity was positively associated with serum leptin, markers of insulin resistance and increased trunk fat mass. Metabolic complications, including type 2 diabetes and dyslipidaemia, were more prevalent in patients with high levels of SA-β-gal, but improved with bariatric surgery whatever the initial adipose tissue senescent status.

CONCLUSIONS/INTERPRETATION

This study highlights a phenotype of senescence in adipose tissue of severely obese individuals, which characterises prominently subcutaneous fat depots. Subcutaneous adipose tissue senescence is significantly linked to altered glucose metabolism and body fat distribution. Elimination of senescent cells through senolytic treatment could alleviate metabolic complications in severely obese people. Graphical abstract.

Inhibition of Aurora-A improves insulin resistance by ameliorating islet inflammation and controlling interleukin-6 in a diabetic mouse model

Aurora-A kinase, a serine/threonine mitotic kinase, is reportedly upregulated in skin tissues of individuals with type 2 diabetes mellitus , although its function in diabetes is unclear. C57BL/6 J mice were utilized to establish a type 2 diabetic model and explore the functions of Aurora-A in diabetes. Aurora-A was highly expressed in the pancreas of the diabetic mice as confirmed by western blot. Inhibition of Aurora-A did not affect fasting blood glucose and body weight, but did improve insulin resistance, as indicated by improved oral glucose tolerance, insulin tolerance, and the Homoeostasis Model Assessment-Insulin Resistance index. Blockade of Aurora-A dramatically decreased the number of infiltrating macrophages in the pancreas in parallel with decreases in the levels of serum insulin and interleukin-6 (IL-6) mRNA. The levels of phosphorylated forms of protein kinase B, which are the key mediators of in insulin resistance, were not induced in liver, adipocyte tissues, and skeletal muscle by alisertib treatment. Our findings indicate that suppression of Aurora-A could at least partially enhance insulin sensitivity by decreasing the number of infiltrating macrophages and IL-6 level in a type 2 diabetic mouse model.

Influence of Obesity and Exercise on β2-Adrenergic-Mediated Anti-Inflammatory Effects in Peritoneal Murine Macrophages

Obesity is a chronic low-grade inflammatory condition, and β2-adrenergic agonists as well as exercise have been proposed as anti-inflammatory strategies in obesity, so it is critical to accurately determine the effects of β2-adrenergic stimulation, especially when combined with other non-pharmacological therapies. The aim of this investigation was to determine the effect of β2-adrenergic activation on the inflammatory profile and phenotype of macrophages, and whether these effects could be affected by obesity and exercise in this condition. High-fat diet-induced obese and lean C57BL/6J mice were allocated to sedentary or exercised groups. The inflammatory profiles and phenotypes of their peritoneal macrophages were assessed by flow cytometry in the presence or absence of the selective β2-adrenergic receptor agonist terbutaline. β2-adrenergic activation caused global phenotypic anti-inflammatory effects in lean and obese sedentary mice, which were more drastic (also including anti-inflammatory effects on the cytokine profile) in obese animals. In exercised lean and obese animals, this anti-inflammatory effect is weaker and only evident by decreased iNOS and IL-8 expression, without changes in the anti-inflammatory markers. Therefore, β2-adrenergic activation leads to anti-inflammatory effects, but these effects are modulated by obesity in sedentary conditions, as well as by regular exercise; but not by obesity in trained conditions.

Complement Properdin Regulates the Metabolo-Inflammatory Response to a High Fat Diet

Background and objectives: Overnutrition leads to a metabolic and inflammatory response that includes the activation of Complement. Properdin is the only amplifier of complement activation and increases the provision of complement activation products. Its absence has previously been shown to lead to increased obesity in mice on a high fat diet. The aim of this study was to determine ways in which properdin contributes to a less pronounced obese phenotype. Materials and Methods: Wild type (WT) and properdin deficient mice (KO) were fed a high-fat diet (HFD) for up to 12 weeks. Results: There was a significant increase in liver triglyceride content in the KO HFD group compared to WT on HFD. WT developed steatosis. KO had an additional inflammatory component (steatohepatitis). Analysis of AKT signalling by phosphorylation array supported a decrease in insulin sensitivity which was greater for KO than WT in liver and kidney. There was a significant decrease of C5L2 in the fat membranes of the KO HFD group compared to the WT HFD group. Circulating microparticles in KO HFD group showed lower presence of C5L2. Expression of the fatty acid transporter CD36 in adipose tissue was increased in KO on HFD and was also significantly increased in plasma of KO HFD mice compared to WT on HFD. CD36 was elevated on microparticles from KO on HFD. Ultrastructural changes consistent with obesity-associated glomerulopathy were observed for both HFD fed genotypes, but tubular strain was greater in KO. Conclusion: Our work demonstrates that complement properdin is a dominant factor in limiting the severity of obesity-associated conditions that impact on liver and kidney. The two receptors, C5L2 and CD36, are downstream of the activity exerted by properdin.

Understanding the Role of Interleukin-6 (IL-6) in the Joint and Beyond: A Comprehensive Review of IL-6 Inhibition for the Management of Rheumatoid Arthritis

Rheumatoid arthritis (RA) is a chronic, debilitating autoimmune disorder involving inflammation and progressive destruction of the joints, affecting up to 1% of the population. The majority of patients with RA have one or more comorbid conditions, the most common being cardiovascular disease, osteoporosis, and depression, the presence of which are associated with poorer clinical outcomes and lower health-related quality of life. RA pathogenesis is driven by a complex network of proinflammatory cells and cytokines, and of these, interleukin-6 (IL-6) plays a key role in the chronic inflammation associated with RA. Through cell signaling that can be initiated by both membrane-bound and soluble forms of its receptor, IL-6 acts both locally to promote joint inflammation and destruction, and in the circulation to mediate extra-articular manifestations of RA, including pain, fatigue, morning stiffness, anemia, and weight loss. This narrative review describes the role of IL-6 in the pathogenesis of RA, its comorbidities, and extra-articular systemic manifestations, and examines the effects of the IL-6 receptor inhibitors sarilumab and tocilizumab on clinical endpoints of RA, patient-reported outcomes, and common comorbidities and extra-articular manifestations.

Treadmill exercise has minimal impact on obesogenic diet-related gut microbiome changes but alters adipose and hypothalamic gene expression in rats

Background

Exercise has been extensively utilised as an effective therapy for overweight- and obesity-associated changes that are linked to health complications. Several preclinical rodent studies have shown that treadmill exercise alongside an unhealthy diet improves metabolic health and microbiome composition. Furthermore, chronic exercise has been shown to alter hypothalamic and adipose tissue gene expression in diet-induced obesity. However, limited work has investigated whether treadmill exercise commenced following exposure to an obesogenic diet is sufficient to alter microbiome composition and metabolic health.

Methods

To address this gap in the literature, we fed rats a high-fat/high-sugar western-style cafeteria diet and assessed the effects of 4 weeks of treadmill exercise on adiposity, diet-induced gut dysbiosis, as well as hypothalamic and retroperitoneal white adipose tissue gene expression. Forty-eight male Sprague-Dawley rats were allocated to either regular chow or cafeteria diet and after 3 weeks half the rats on each diet were exposed to moderate treadmill exercise for 4 weeks while the remainder were exposed to a stationary treadmill.

Results

Microbial species diversity was uniquely reduced in exercising chow-fed rats, while microbiome composition was only changed by cafeteria diet. Despite limited effects of exercise on overall microbiome composition, exercise increased inferred microbial functions involved in metabolism, reduced fat mass, and altered adipose and hypothalamic gene expression. After controlling for diet and exercise, adipose Il6 expression and liver triglyceride concentrations were significantly associated with global microbiome composition.

Conclusions

Moderate treadmill exercise induced subtle microbiome composition changes in chow-fed rats but did not overcome the microbiome changes induced by prolonged exposure to cafeteria diet. Predicted metabolic function of the gut microbiome was increased by exercise. The effects of exercise on the microbiome may be modulated by obesity severity. Future work should investigate whether exercise in combination with microbiome-modifying interventions can synergistically reduce diet- and obesity-associated comorbidities.

Role of Skeletal Muscle in Insulin Resistance and Glucose Uptake

The skeletal muscle is the largest organ in the body, by mass. It is also the regulator of glucose homeostasis, responsible for 80% of postprandial glucose uptake from the circulation. Skeletal muscle is essential for metabolism, both for its role in glucose uptake and its importance in exercise and metabolic disease. In this article, we give an overview of the importance of skeletal muscle in metabolism, describing its role in glucose uptake and the diseases that are associated with skeletal muscle metabolic dysregulation. We focus on the role of skeletal muscle in peripheral insulin resistance and the potential for skeletal muscle-targeted therapeutics to combat insulin resistance and diabetes, as well as other metabolic diseases like aging and obesity. In particular, we outline the possibilities and pitfalls of the quest for exercise mimetics, which are intended to target the molecular mechanisms underlying the beneficial effects of exercise on metabolic disease. We also provide a description of the molecular mechanisms that regulate skeletal muscle glucose uptake, including a focus on the SNARE proteins, which are essential regulators of glucose transport into the skeletal muscle. © 2020 American Physiological Society. Compr Physiol 10:785-809, 2020.

Activation of adipose tissue glycerokinase contributes to increased white adipose tissue mass in mice fed a high-fat diet

PURPOSE

Investigate the pathways of glycerol-3-P (G3P) generation for triacylglycerol (TAG) synthesis in retroperitoneal (RWAT) and epididymal (EWAT) white adipose tissues from high-fat diet (HFD)-fed mice.

METHODS

Mice were fed for 8 weeks a HFD and glycolysis, glyceroneogenesis and direct phosphorylation of glycerol were evaluated, respectively, by 2-deoxyglucose uptake, phosphoenolpyruvate carboxykinase (PEPCK-C) activity and pyruvate incorporation into TAG-glycerol, and glycerokinase activity and glycerol incorporation into TAG-glycerol in both tissues.

RESULTS

HFD increased body and adipose tissue mass and serum levels of glucose and insulin, which were accompanied by glucose intolerance. RWAT and EWAT from HFD-fed mice had increased rates of de novo fatty acid (FA) synthesis (52% and 255%, respectively). HFD increased lipoprotein lipase (LPL) activity and content in EWAT (107%), but decreased in RWAT (79%). HFD decreased the lipolytic response to norepinephrine (57%, RWAT and 25%, EWAT), β3-adrenoceptor content (50%), which was accompanied by a decrease in phosphorylated-hormone-sensitive lipase (~80%) and phosphorylated-adipocyte triacylglycerol lipase (~60%) in both tissues. HFD decreased the in vitro rates of glucose uptake (3.5- and 6-fold), as well as in glyceride-glycerol synthesis from pyruvate (~3.5-fold) without changes in PEPCK-C activity and content in RWAT and EWAT, but increased glycerokinase activity(~3-fold) and content (90 and 40%) in both tissues.

CONCLUSION

The data suggest that direct phosphorylation of glycerol by glycerokinase may be responsible for maintaining the supply of G3P for the existing rates of FA esterification and TAG synthesis in RWAT and EWAT from HFD-fed mice, contributing, along with a lower lipolytic response to norepinephrine, to higher adiposity.

Catecholamines suppress fatty acid re-esterification and increase oxidation in white adipocytes via STAT3

Catecholamines stimulate the mobilization of stored triglycerides in adipocytes to provide fatty acids (FAs) for other tissues. However, a large proportion is taken back up and either oxidized or re-esterified. What controls the disposition of these FAs in adipocytes remains unknown. Here, we report that catecholamines redirect FAs for oxidation through the phosphorylation of signal transducer and activator of transcription 3 (STAT3). Adipocyte STAT3 is phosphorylated upon activation of β-adrenergic receptors, and in turn suppresses FA re-esterification to promote FA oxidation. Adipocyte-specific Stat3 KO mice exhibit normal rates of lipolysis, but exhibit defective lipolysis-driven oxidative metabolism, resulting in reduced energy expenditure and increased adiposity when they are on a high-fat diet. This previously unappreciated, non-genomic role of STAT3 explains how sympathetic activation can increase both lipolysis and FA oxidation in adipocytes, revealing a new regulatory axis in metabolism.

Elevated First-Trimester Neutrophil Count Is Closely Associated With the Development of Maternal Gestational Diabetes Mellitus and Adverse Pregnancy Outcomes

Chronic low-grade inflammation plays a central role in the pathophysiology of gestational diabetes mellitus (GDM). To investigate the ability of different inflammatory blood cell parameters in predicting the development of GDM and pregnancy outcomes, 258 women with GDM and 1,154 women without were included in this retrospective study. First-trimester neutrophil count outperformed white blood cell count and the neutrophil-to-lymphocyte ratio in the predictability for GDM. Subjects were grouped based on tertiles of neutrophil count during their first-trimester pregnancy. The results showed that as the neutrophil count increased, there was a stepwise increase in GDM incidence as well as in glucose and glycosylated hemoglobin levels, HOMA for insulin resistance (HOMA-IR), macrosomia incidence, and newborn weight. Neutrophil count was positively associated with prepregnancy BMI, HOMA-IR, and newborn weight. Additionally, neutrophil count was an independent risk factor for the development of GDM, regardless of the history of GDM. Spline regression showed that there was a significant linear association between GDM incidence and the continuous neutrophil count when it was >5.0 × 10⁹/L. This work suggested that the first-trimester neutrophil count is closely associated with the development of GDM and adverse pregnancy outcomes.

Association of Single Nucleotide Polymorphisms of the IL-6, IL-10, and TNF-α Genes with Susceptibility to Gestational Diabetes Mellitus

Objective: To investigate any associations between the single nucleotide polymorphisms (SNPs) at the interleukin-6 (IL-6) rs1800796, interleukin-10 (IL-10) rs1800896, and the tumor necrosis factor-alpha (TNF-α) rs1800629 loci with gestational diabetes mellitus (GDM) susceptibility. Materials and Methods: A total of 242 GDM patients and 242 healthy controls were enrolled in this study. The genotypes of the IL-6 rs1800796, IL-10 rs1800896, and TNF-α rs1800629 loci were analyzed by Sanger sequencing. Interactions among these SNPs were analyzed through multifactor dimensionality reduction. Results: Women with the IL-6 rs1800796 G allele had a higher GDM susceptibility risk than those with the C allele (odds ratio [OR] = 1.44, 95% confidence interval [CI]: 1.10-1.90, p = 0.010). Women with the IL-10 rs1800896 C allele had a higher risk of GDM susceptibility than those with the T allele (OR = 2.94, 95% CI: 1.87-4.63, p < 0.001). Women with the TNF-α rs1800629 A allele had a higher risk of susceptibility to GDM than those with the G allele (OR = 3.73, 95% CI: 2.25-6.18, p < 0.001). The plasma levels of IL-6 and TNF-α in GDM patients were significantly higher than those in the control group, and the levels of IL-10 were significantly lower than those in the control group (p < 0.001). Women with the IL-6 rs1800796 CG/GG genotypes had higher plasma IL-6 levels than those with the CC genotype (p < 0.05). Women with the IL-10 rs1800896 TT genotype had higher IL-10 levels than those with the TC/CC genotypes (p < 0.05), and those with the TNF-α rs1800629 GA/AA genotypes had higher TNF-α levels than those with the GG genotype (p < 0.05). Conclusion: The results of this study show that the IL-6 rs1800796 G allele, the IL-10 rs1800896 C allele, and the TNF-α rs1800629 A allele are significantly associated with an increased risk of susceptibility to GDM.

In-Vitro-Generated Hypertrophic-Like Adipocytes Displaying PPARG Isoforms Unbalance Recapitulate Adipocyte Dysfunctions In Vivo

Reduced neo-adipogenesis and dysfunctional lipid-overloaded adipocytes are hallmarks of hypertrophic obesity linked to insulin resistance. Identifying molecular features of hypertrophic adipocytes requires appropriate in vitro models. We describe the generation of a model of human hypertrophic-like adipocytes directly comparable to normal adipose cells and the pathologic evolution toward hypertrophic state. We generate in vitro hypertrophic cells from mature adipocytes, differentiated from human mesenchymal stem cells. Combining optical, confocal, and transmission electron microscopy with mRNA/protein quantification, we characterize this cellular model, confirming specific alterations also in subcutaneous adipose tissue. Specifically, we report the generation and morphological/molecular characterization of human normal and hypertrophic-like adipocytes. The latter displays altered morphology and unbalance between canonical and dominant negative (PPARGΔ5) transcripts of PPARG, paralleled by reduced expression of PPARγ targets, including GLUT4. Furthermore, the unbalance of PPARγ isoforms associates with GLUT4 down-regulation in subcutaneous adipose tissue of individuals with overweight/obesity or impaired glucose tolerance/type 2 diabetes, but not with normal weight or glucose tolerance. In conclusion, the hypertrophic-like cells described herein are an innovative tool for studying molecular dysfunctions in hypertrophic obesity and the unbalance between PPARγ isoforms associates with down-regulation of GLUT4 and other PPARγ targets, representing a new hallmark of hypertrophic adipocytes.

Metabolic inflammation as an instigator of fibrosis during non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is characterized by excessive storage of fatty acids in the form of triglycerides in hepatocytes. It is most prevalent in western countries and includes a wide range of clinical and histopathological findings, namely from simple steatosis to steatohepatitis and fibrosis, which may lead to cirrhosis and hepatocellular cancer. The key event for the transition from steatosis to fibrosis is the activation of quiescent hepatic stellate cells (qHSC) and their differentiation to myofibroblasts. Pattern recognition receptors (PRRs), expressed by a plethora of immune cells, serve as essential components of the innate immune system whose function is to stimulate phagocytosis and mediate inflammation upon binding to them of various molecules released from damaged, apoptotic and necrotic cells. The activation of PRRs on hepatocytes, Kupffer cells, the resident macrophages of the liver, and other immune cells results in the production of proinflammatory cytokines and chemokines, as well as profibrotic factors in the liver microenvironment leading to qHSC activation and subsequent fibrogenesis. Thus, elucidation of the inflammatory pathways associated with the pathogenesis and progression of NAFLD may lead to a better understanding of its pathophysiology and new therapeutic approaches.

Metabolic Inflammation-A Role for Hepatic Inflammatory Pathways as Drivers of Comorbidities in Nonalcoholic Fatty Liver Disease?

Nonalcoholic fatty liver disease (NAFLD) is a global and growing health concern. Emerging evidence points toward metabolic inflammation as a key process in the fatty liver that contributes to multiorgan morbidity. Key extrahepatic comorbidities that are influenced by NAFLD are type 2 diabetes, cardiovascular disease, and impaired neurocognitive function. Importantly, the presence of nonalcoholic steatohepatitis and advanced hepatic fibrosis increase the risk for systemic comorbidity in NAFLD. Although the precise nature of the crosstalk between the liver and other organs has not yet been fully elucidated, there is emerging evidence that metabolic inflammation-in part, emanating from the fatty liver-is the engine that drives cellular dysfunction, cell death, and deleterious remodeling within various body tissues. This review describes several inflammatory pathways and mediators that have been implicated as links between NAFLD and type 2 diabetes, cardiovascular disease, and neurocognitive decline.

Glycemic Control after Initiating Direct-Acting Antiviral Agents in Patients with Hepatitis C Virus and Type 2 Diabetes Mellitus Using the United States Integrated Healthcare System

Objective:

Hepatitis C virus (HCV) has an increased risk of Type 2 diabetes mellitus (T2DM). Prior studies found that the eradication of HCV with direct-acting antiviral (DAA) agents led to improved glycemic control in patients with T2DM. We aimed to identify the association between HCV eradication and glycemic control in patients diagnosed with HCV and T2DM.

Methods:

A retrospective observational study was conducted to identify adult patients diagnosed with HCV from January 1, 2014, to August 31, 2017. Patients were included if they were initiated on one of the following DAA agents within the study period: Sofosbuvir/velpatasvir, sofosbuvir/ledispavir, elbasvir/grazopevir. Patients were also required to have the diagnosis of T2DM. The primary outcome of this study was the average change in glycosylated hemoglobin (HbA1c) pre- versus post-DAA agents.

Findings:

Our final cohort consisted of 996 patients diagnosed with HCV and T2DM: Patients who achieved sustained virologic response (SVR) (n = 937, 94%) and those who did not achieve SVR (n = 59, 6%). In the SVR group, there was a 0.3950% reduction in HbA1c (P < 0.0001) and in those who did not achieve SVR group, there was 0.3532% reduction in HbA1c (P = 0.0051). In the overall study population, SVR group had 0.04% more reduction in HbA1c but was not statistically significant (P = 0.7441).

Conclusion:

Both groups had statistically significant reductions in HbA1c when comparing the mean change in average HbA1c pre-versus post-DAA agent. Patients who achieved SVR had a greater absolute reduction in HbA1c by 0.04%; however, this was not statistically significant.

Non-heme iron enzyme-catalyzed complex transformations: Endoperoxidation, cyclopropanation, orthoester, oxidative C-C and C-S bond formation reactions in natural product biosynthesis

Non-heme iron enzymes catalyze a wide range of chemical transformations, serving as one of the key types of tailoring enzymes in the biosynthesis of natural products. Hydroxylation reaction is the most common type of reactions catalyzed by these enzymes and hydroxylation reactions have been extensively investigated mechanistically. However, the mechanistic details for other types of transformations remain largely unknown or unexplored. In this paper, we present some of the most recently discovered transformations, including endoperoxidation, orthoester formation, cyclopropanation, oxidative C-C and C-S bond formation reactions. In addition, many of them are multi-functional enzymes, which further complicate their mechanistic investigations. In this work, we summarize their biosynthetic pathways, with special emphasis on the mechanistic details available for these newly discovered enzymes.

Shared pathways for neuroprogression and somatoprogression in neuropsychiatric disorders

Activated immune-inflammatory, oxidative and nitrosative stress (IO&NS) pathways and consequent mitochondrial aberrations are involved in the pathophysiology of psychiatric disorders including major depression, bipolar disorder and schizophrenia. They offer independent and shared contributions to pathways underpinning medical comorbidities including insulin resistance, metabolic syndrome, obesity and cardiovascular disease - herein conceptualized as somatoprogression. This narrative review of human studies aims to summarize relationships between IO&NS pathways, neuroprogression and somatoprogression. Activated IO&NS pathways, implicated in the neuroprogression of psychiatric disorders, affect the pathogenesis of comorbidities including insulin resistance, dyslipidaemia, obesity and hypertension, and by inference, metabolic syndrome. These conditions activate IO&NS pathways, exacerbating neuroprogression in psychiatric disorders. The processes whereby proinflammatory cytokines, nitrosative and endoplasmic reticulum stress, NADPH oxidase isoforms, PPARγ inactivation, SIRT1 deficiency and intracellular signalling pathways impact lipid metabolism and storage are considered. Through associations between body mass index, chronic neuroinflammation and FTO expression, activation of IO&NS pathways arising from somatoprogression may contribute to neuroprogression. Early evidence highlights the potential of adjuvants targeting IO&NS pathways for treating somatoprogression and neuroprogression.

Liraglutide improves insulin sensitivity in high fat diet induced diabetic mice through multiple pathways

Glucagon like peptide-1 (GLP-1) promotes postprandial insulin secretion. Liraglutide, a full agonist of the GLP-1 receptor, reduces body weight, improve insulin sensitivity, and alleviate Non Alcoholic Fatty Liver Disease (NAFLD). However, the underlying mechanisms remain unclear. This study aims to explore the underlying mechanisms and cell signaling pathways involved in the anti-obesity and anti-inflammatory effects of liraglutide. Mice were fed a high fat high sucrose diet to induce diabetes, diabetic mice were divided into two groups and injected with liraglutide or vehicle for 14 days. Liraglutide treatment improved insulin sensitivity, accompanied with reduced expression of the phosphorylated Acetyl-CoA carboxylase-2 (ACC2) and upregulation of long chain acyl CoA dehydrogenase (LCAD) in insulin sensitive tissues. Furthermore, liraglutide induced adenosine monophosphate-activated protein kinase-α (AMPK-α) and Sirtuin-1(Sirt-1) protein expression in liver and perigonadal fat. Liraglutide induced elevation of fatty acid oxidation in these tissues may be mediated through the AMPK-Sirt-1 cell signaling pathway. In addition, liraglutide induced brown adipocyte differentiation in skeletal muscle, including induction of uncoupling protein-1 (UCP-1) and PR-domain-containing-16 (PRDM-16) protein in association with induction of SIRT-1. Importantly, liraglutide displayed anti-inflammation effect. Specifically, liraglutide led to a significant reduction in circulating interleukin-1 β (IL-1 β) and interleukin-6 (IL-6) as well as hepatic IL-1 β and IL-6 content. The expression of inducible nitric oxide synthase (iNOS-1) and cyclooxygenase-2 (COX-2) in insulin sensitive tissues was also reduced following liraglutide treatment. In conclusion, liraglutide improves insulin sensitivity through multiple pathways resulting in reduction of inflammation, elevation of fatty acid oxidation, and induction of adaptive thermogenesis.

Crystal Structure of the Ergothioneine Sulfoxide Synthase from Candidatus Chloracidobacterium thermophilum and Structure-Guided Engineering To Modulate Its Substrate Selectivity

Ergothioneine is a thiohistidine derivative with potential benefits on many aging-related diseases. The central step of aerobic ergothioneine biosynthesis is the oxidative C-S bond formation reaction catalyzed by mononuclear nonheme iron sulfoxide synthases (EgtB and Egt1). Thus far, only the Mycobacterium thermoresistibile EgtB (EgtB _Mth ) crystal structure is available, while the structural information for the more industrially attractive Egt1 enzyme is not. Herein, we reported the crystal structure of the ergothioneine sulfoxide synthase (EgtB _Cth ) from Candidatus Chloracidobacterium thermophilum. EgtB _Cth has both EgtB- and Egt1-type of activities. Guided by the structural information, we conducted Rosetta Enzyme Design calculations, and we biochemically demonstrated that EgtB _Cth can be engineered more toward Egt1-type of activity. This study provides information regarding the factors governing the substrate selectivity in Egt1- and EgtB-catalysis and lays the groundwork for future sulfoxide synthase engineering toward the development of an effective ergothioneine process through a synthetic biology approach.

Association of proinflammatory genes expression with serum interleukin 1β and free fatty acids in metabolically healthy and unhealthy abdominally obese individuals: a case-control study

Background

Proinflammatory genes are highly expressed in several metabolic disorders associated with obesity. But it is not clarified whether gene expression levels and downstream inflammatory markers are related to the metabolic state or the presence of obesity. Hence, the present study aimed to compare Toll-Like Receptor 2 (TLR2), Myeloid Differentiation Factor 88 (MyD88), and NFĸB mRNA expression levels between metabolically healthy abdominally obese (MHAO) and metabolically unhealthy abdominally obese (MUAO) individuals.

Results

We compared mRNA expression levels of the genes as well as serum FFAs and IL-1β in MUAO (n = 36) and MHAO (n = 34) groups. Serum FBS, TG, and HDL-C in addition to systolic and diastolic blood pressure were significantly higher in MUAO than MHAO groups (p < 0.05). The odds of MUAO was significantly decreased with high HDL-C (OR = 0.22, 95%CI: 0.08–0.63) and increased with high FBS (OR = 7.04, 95%CI: 1.42–34.69) and TG (OR = 30.55, 95%CI: 7.48–60.67). There were no significant differences in proinflammatory genes as well as serum FFAs and IL-1β between the two groups. No associations were found between the genes expression and serum markers. However, NFĸB expression was significantly correlated with TLR2 and MyD88 (r = 0.747; p < 0.001). Significant correlations were also noticed between TLR2 and MyD88 expression as well as between serum FFAs and IL-1β in each group (p < 0.001).

Conclusion

Serum concentration of IL-1β, FFAs, and mRNA expression levels of TLR2, MyD88, and NFĸB may be resulted from abdominal obesity and not be related to the presence or absence of metabolic health.