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Context Metabolic associated fatty liver disease (MAFLD) is the hepatic manifestation of obesity-related metabolic syndrome (MetS). Noninvasive biomarkers for monitoring the progression and severity of these metabolic comorbidities are needed. Objectives To investigate the associations of serum thrombospondin-2 (TSP2) with MetS and MAFLD severity, and the potential diagnostic value of serum TSP2 for identifying at-risk metabolic associated steatohepatitis (MASH). Methods Blood samples, clinical data, and liver biopsies were collected from consecutively recruited 252 individuals with morbid obesity receiving bariatric surgery. Histopathology samples of liver biopsies were examined in a blinded fashion by 3 independent pathologists. Serum TSP2 levels were measured by enzyme-linked immunosorbent assay. Results Serum TSP2 levels were significantly elevated in MetS (1.58 [1.07-2.20] ng/mL) compared with non-MetS (1.28 [0.84-1.73] ng/mL; P = .006) in obese patients and positively correlated with increasing number of the MetS components, fasting glucose, glycated hemoglobin, fasting insulin, C-peptide, and homeostatic model assessment of insulin resistance after adjustment of conventional confounders. Serum TSP2 levels differentiated MASH (1.74 [1.32-3.09] ng/mL) from the other non-MASH less severe groups: normal liver (1.41 [1.04-1.63] ng/mL), simple steatosis (1.45 [0.89-1.92] ng/mL), and borderline MASH (1.30 [0.99-2.17] ng/mL) (P Conclusion Serum TSP2 is closely associated with severity and progression of MetS and MAFLD, and is a promising noninvasive biomarker for differentiating MASH from benign steatosis and identifying at-risk MASH patients among individuals with obesity.

Marked enhancement of neutrophil infiltration in the liver is a hallmark of acute liver failure (ALF), a severe life-threatening disease with varying etiologies. However, the mechanisms and pathophysiological role corresponding to hepatic neutrophil infiltration during ALF development remain poorly characterized.Experimental ALF was induced in 10-week-old male microRNA-223 (miR-223) knockout (KO) mice, neutrophil elastase (NE) KO mice, and wild-type controls by intraperitoneal injection of galactosamine hydrochloride and lipopolysaccharide. Age-matched mice were injected with phosphate-buffered saline and served as vehicle controls.Mouse liver with ALF showed evident formation of neutrophil extracellular traps (NETs), which were enhanced markedly in miR-223 KO mice. The blockade of NETs by pharmacologic inhibitor GSK484 significantly attenuated neutrophil infiltration and massive necrosis in mouse liver with ALF. ALF-related hepatocellular damage and mortality in miR-223 KO mice were aggravated significantly and accompanied by potentiated neutrophil infiltration in the liver when compared with wild-type controls. Transcriptomic analyses showed that miR-223 deficiency in bone marrow predominantly caused the enrichment of pathways involved in neutrophil degranulation. Likewise, ALF-induced hepatic NE enrichment was potentiated in miR-223 KO mice. Genetic ablation of NE blunted the formation of NETs in parallel with significant attenuation of ALF in mice. Pharmaceutically, pretreatment with the NE inhibitor sivelestat protected mice against ALF.The present study showed the miR-223/NE axis as a key modulator of NETs, thereby exacerbating oxidative stress and neutrophilic inflammation to potentiate hepatocellular damage and liver necrosis in ALF development, and offering potential targets against ALF.

Although mitophagy is known to restrict NLRP3 inflammasome activation, the underlying regulatory mechanism remains poorly characterized. Here we describe a type of early endosome-dependent mitophagy that limits NLRP3 inflammasome activation. Deletion of the endosomal adaptor protein APPL1 impairs mitophagy, leading to accumulation of damaged mitochondria producing reactive oxygen species (ROS) and oxidized cytosolic mitochondrial DNA, which in turn trigger NLRP3 inflammasome overactivation in macrophages. NLRP3 agonist causes APPL1 to translocate from early endosomes to mitochondria, where it interacts with Rab5 to facilitate endosomal-mediated mitophagy. Mice deficient for APPL1 specifically in hematopoietic cell are more sensitive to endotoxin-induced sepsis, obesity-induced inflammation and glucose dysregulation. These are associated with increased expression of systemic interleukin-1β, a major product of NLRP3 inflammasome activation. Our findings indicate that the early endosomal machinery is essential to repress NLRP3 inflammasome hyperactivation by promoting mitophagy in macrophages.

Hepatosteatosis, defined as excessive intrahepatic lipid accumulation, represents the first step of nonalcoholic fatty liver disease (NAFLD). When combined with additional cellular stress, this benign status progresses to local and systemic pathological conditions such as nonalcoholic steatohepatitis and insulin resistance. However, the molecular events directly caused by hepatic lipid buildup, in terms of its impact on liver biology and peripheral organs, remain unclear. Carnitine palmitoyltransferase 1A (CPT1A) is the rate-limiting enzyme for long-chain fatty acid β-oxidation in the liver. In this study, we use hepatocyte-specific Cpt1a knockout (LKO) mice to investigate the physiological consequences of abolishing hepatic long-chain fatty acid metabolism. Compared with the wild-type littermates, high-fat diet (HFD)–fed LKO mice displayed more severe hepatosteatosis but were otherwise protected against diet-induced weight gain, insulin resistance, hepatic endoplasmic reticulum stress, inflammation, and damage. Interestingly, increased energy expenditure was observed in LKO mice, accompanied by enhanced adipose tissue browning. RNA-sequencing analysis revealed that the peroxisome proliferator–activated receptor α–fibroblast growth factor 21 (FGF21) axis was activated in liver of LKO mice. Importantly, antibody-mediated neutralization of FGF21 abolished the healthier metabolic phenotype and adipose browning in LKO mice, indicating that the elevation of FGF21 contributes to the improved liver pathology and adipose browning in HFD-treated LKO mice. Liver with deficient CPT1A expression adopts a healthy steatotic status that protects against HFD-evoked liver damage and potentiates adipose browning in an FGF21-dependent manner. Inhibition of hepatic CPT1A may serve as a viable strategy for the treatment of obesity and NAFLD.

Type 2 diabetes mellitus (T2DM) has become a global health problem with no cure. Despite lifestyle modifications and various pharmaceutical options, the achievement of stable and durable glucose control along with effective prevention of T2DM-related cardiovascular complications remains a challenging task in clinical management. With its selective high abundance in metabolic tissues (adipose tissue, liver, and pancreas), β-Klotho is the essential component of fibroblast growth factor (FGF) receptor complexes. It is essential for high-affinity binding of endocrine FGF19 and FGF21 to evoke the signaling cascade actively involved in homeostatic maintenance of glucose metabolism and energy expenditure. In this Review, we discuss the biological function of β-Klotho in the regulation of glucose metabolism and offer mechanistic insights into its involvement in the pathophysiology of T2DM. We review our current understanding of the endocrine axis comprised of β-Klotho and FGFs (FGF19 and FGF21) and its regulatory effects on glucose metabolism under physiological and T2DM conditions. We also highlight advances in the development and preclinical validation of pharmacological compounds that target β-Klotho and/or the β-Klotho-FGFRs complex for the treatment of T2DM. Given the remarkable advances in this field, we also discuss outstanding research questions and the many challenges in the clinical development of β-Klotho-based therapies.

Gestational diabetes mellitus (GDM) characterized by hyperglycemia during pregnancy is a risk factor for various maternal and fetal complications. The key pathophysiological mechanisms underlying its development have not been elucidated, largely due to the lack of a model that accurately simulates the major clinical and pathological features of human GDM. In this review, we discuss the refined criteria for an ideal animal model of GDM, focusing on the key clinical and pathophysiological characteristics of human GDM. We provide a comprehensive overview of different models and currently used species for GDM research. In general, insulin insufficiency consequent to pancreatic β-cell death represents the current leading strategy to mimic human GDM-like hyperglycemia in animals. Nonetheless, these models have a limited capacity to mimic the natural history of GDM, the marked alteration in circulating estrogen/ progestogen, obesity and its related metabolic complications. We discuss emerging evidence of the increased susceptibility to GDM in rodents and large animals with genetic modifications in pregnancy-related hormones. An appraisal of current GDM models suggests that a combination strategy involving dietary stress, pregnancy-related hormones, insulin resistance and metabolic disorders might enable the development of better GDM models and expedite the translation of basic research findings to GDM treatment.

The enrichment of innate immune cells and the enhanced inflammation represent the hallmark of non-alcoholic steatohepatitis (NASH), the advanced subtype with a significantly increased risk of progression to end-stage liver diseases within the spectrum of non-alcoholic fatty liver disease. Neutrophils are traditionally recognized as key components in the innate immune system to defend against pathogens. Recently, a growing body of evidence supports neutrophils as emerging key player in mediating the transition from steatosis to NASH, which is largely inspired by the histological findings in human liver biopsy indicating the enhanced infiltration of neutrophils as one of the key histological features of NASH. In this review, we discuss data regarding histological perspectives of hepatic infiltration of neutrophils in NASH. We also highlight the pathophysiological role of neutrophils in promoting metabolic inflammation in the liver through the release of a vast array of granule proteins, the interaction with other pro-inflammatory immune cells, and the formation of neutrophil extracellular traps. Neutrophil granule proteins possess pleiotropic effects on regulating neutrophil biology and functions. A variety of granule proteins (including lipocalin-2, myeloperoxidase, proteinase 3, neutrophil elastase, etc.) produced by neutrophils enhance liver metabolic inflammation, thereby promoting NASH progression by mediating neutrophil-macrophage interaction. Therapeutically, pharmacological inhibitors targeting neutrophil granule proteins hold promise to combat NASH. In addition, this article also summarizes potentials of neutrophils and its derived various granule proteins for the accurate, even non-invasive diagnosis of NASH.

Polycystic ovary syndrome (PCOS) affects approximately 15% of women of reproductive age worldwide. It is the most prevalent endocrine disorder with marked risks for female infertility, type 2 diabetes mellitus (T2DM), psychiatric disorders and gynecological cancers. Although the pathophysiology of PCOS remains largely elusive, growing evidence suggests a close link with obesity and its related metabolic disorders. As a highly active endocrine cell population, hypertrophic adipocytes in obesity have disturbed production of a vast array of adipokines, biologically active peptides that exert pleiotropic effects on homeostatic regulation of glucose and lipid metabolism. In parallel with their crucial roles in the pathophysiology of obesity-induced metabolic diseases, adipokines have recently been identified as promising targets for novel therapeutic strategies for multiple diseases. Current treatments for PCOS are suboptimal with insufficient alleviation of all symptoms. Novel findings in adipokine-targeted agents may provide important insight into the development of new drugs for PCOS. This Review presents an overview of the current understanding of mechanisms that link PCOS to obesity and highlights emerging evidence of adipose-ovary crosstalk as a pivotal mediator of PCOS pathogenesis. We summarize recent findings of preclinical and clinical studies that reveal the therapeutic potential of adipokine-targeted novel approaches to PCOS and its related metabolic disorders. We also discuss the critical gaps in knowledge that need to be addressed to guide the development of adipokine-based novel therapies for PCOS.

Background & Aims Hepatosteatosis, defined as excessive intrahepatic lipid accumulation, represents the first step of NAFLD. When combined with additional cellular stress, this benign status progresses to local and systemic pathological conditions such as NASH and insulin resistance. However, the molecular events directly caused by hepatic lipid build-up, in terms of its impact on liver biology and other peripheral organs, remain unclear. Carnitine palmitoyltransferase 1A (CPT1A) is the rate limiting enzyme for long chain fatty acid beta-oxidation in the liver. Here we utilise hepatocyte-specific Cpt1a knockout (LKO) mice to investigate the physiological consequences of abolishing hepatic long chain fatty acid metabolism. Approach & Results Compared to the wild-type (WT) littermates, high fat diet (HFD)-fed LKO mice displayed more severe hepatosteatosis but were otherwise protected against diet-induced weight gain, insulin resistance, hepatic ER stress, inflammation and damage. Interestingly, increased energy expenditure was observed in LKO mice, accompanied by enhanced adipose tissue browning. RNAseq analysis revealed that the peroxisome proliferator activator alpha (PPARα)- fibroblast growth factor 21 (FGF21) axis was activated in liver of LKO mice. Importantly, antibody-mediated neutralization of FGF21 abolished the healthier metabolic phenotype and adipose browning in LKO mice, indicating that the elevation of FGF21 contributes to the improved liver pathology and adipose browning in HFD-treated LKO mice. Conclusions Liver with deficient CPT1A expression adopts a healthy steatotic status that protects against HFD-evoked liver damage and potentiates adipose browning in an FGF21-dependent manner. Inhibition of hepatic CPT1A may serve as a viable strategy for the treatment of obesity and NAFLD.

Hepatosteatosis, defined as excessive intrahepatic lipid accumulation, represents the first step of NAFLD. When combined with additional cellular stress, this benign status progresses to local and systemic pathological conditions such as NASH and insulin resistance. However, the molecular events directly caused by hepatic lipid build-up, in terms of its impact on liver biology and peripheral organs, remain unclear. Carnitine palmitoyltransferase 1A (CPT1A) is the rate limiting enzyme for long chain fatty acid beta-oxidation in the liver. Here we utilise hepatocyte-specificCompared to the wild-type (WT) littermates, high fat diet (HFD)-fed LKO mice displayed more severe hepatosteatosis but were otherwise protected against diet-induced weight gain, insulin resistance, hepatic ER stress, inflammation and damage. Interestingly, increased energy expenditure was observed in LKO mice, accompanied by enhanced adipose tissue browning. RNAseq analysis revealed that the peroxisome proliferator activator alpha (PPARα)- fibroblast growth factor 21 (FGF21) axis was activated in liver of LKO mice. Importantly, antibody-mediated neutralization of FGF21 abolished the healthier metabolic phenotype and adipose browning in LKO mice, indicating that the elevation of FGF21 contributes to the improved liver pathology and adipose browning in HFD-treated LKO mice.Liver with deficient CPT1A expression adopts a healthy steatotic status that protects against HFD-evoked liver damage and potentiates adipose browning in an FGF21-dependent manner. Inhibition of hepatic CPT1A may serve as a viable strategy for the treatment of obesity and NAFLD.

Type 2 diabetes mellitus, obesity, hypertension, and other associated metabolic complications have been demonstrated as a crucial contributor to the enhanced morbidity and mortality of patients with coronavirus disease 2019 (COVID-19). Data on the interplay between metabolic comorbidities and the outcomes in patients with COVID-19 have been emerging and rapidly increasing. This implies a mechanistic link between metabolic diseases and COVID-19 resulting in the exacerbation of the condition. Nonetheless, new evidences are emerging to support insulin-mediated aggressive glucose-lowering treatment as a possible trigger of high mortality rate in diabetic COVID-19 patients, putting the clinician in a confounding and difficult dilemma for the treatment of COVID-19 patients with metabolic comorbidities. Thus, this review discusses the pathophysiological link among severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), angiotensin-converting enzyme 2 (ACE2), metabolic complications, and severe inflammation in COVID-19 development, especially in those with multi-organ injuries. We discuss the influence of several routinely used drugs in COVID-19 patients, including anti-inflammatory and anti-coagulant drugs, antidiabetic drugs, renin-angiotensin-aldosterone system inhibitors. Especially, we provide a balanced overview on the clinical application of glucose-lowering drugs (insulin and metformin), angiotensin-converting-enzyme inhibitors, and angiotensin receptor blockers. Although there is insufficient evidence from clinical or basic research to comprehensively reveal the mechanistic link between adverse outcomes in COVID-19 and metabolic comorbidities, it is hoped that the update in the current review may help to better outline the optimal strategies for clinical management of COVID-19 patients with metabolic comorbidities.

Adipose tissue macrophage (ATM) inflammation is involved with meta-inflammation and pathology of metabolic complications. Here we report that in adipocytes, elevated lactate production, previously regarded as the waste product of glycolysis, serves as a danger signal to promote ATM polarization to an inflammatory state in the context of obesity. Adipocyte-selective deletion of lactate dehydrogenase A (Ldha), the enzyme converting pyruvate to lactate, protects mice from obesity-associated glucose intolerance and insulin resistance, accompanied by a lower percentage of inflammatory ATM and reduced production of pro-inflammatory cytokines such as interleukin 1β (IL-1β). Mechanistically, lactate, at its physiological concentration, fosters the activation of inflammatory macrophages by directly binding to the catalytic domain of prolyl hydroxylase domain-containing 2 (PHD2) in a competitive manner with α-ketoglutarate and stabilizes hypoxia inducible factor (HIF-1α). Lactate-induced IL-1β was abolished in PHD2-deficient macrophages. Human adipose lactate level is positively linked with local inflammatory features and insulin resistance index independent of the body mass index (BMI). Our study shows a critical function of adipocyte-derived lactate in promoting the pro-inflammatory microenvironment in adipose and identifies PHD2 as a direct sensor of lactate, which functions to connect chronic inflammation and energy metabolism.

Study question Are circulating profiles of metabolic-related hormones also associated with the missed abortion (MA) in humans? Summary answer Serum levels of fatty acid-binding protein–4 (FABP4) and fibroblast growth factor 21 (FGF21) are positively associated with MA. What is known already A cluster of endocrine hormones, including FABP4, FGF21, adiponectin, lipocalin–2 (LCN2), exhibit pleiotropic effects on regulating systematic metabolism. Serum levels of them are associated with gestational obesity and diabetes and affect pregnancy outcomes, however, the relationship between their circulating profiles and MA is under-investigated. Study design, size, duration 78 patients with MA and 86 healthy pregnant subjects matching on maternal age and body mass index (BMI) were nested from a prospective cohort in the Chinese population. Participants/materials, setting, methods Fasting serum samples from all participants were collected to test their serum levels of FGF21, FABP4, adiponectin, and LCN2 by enzyme-linked immunosorbent assay method (ELISA). Main results and the role of chance There were no significant differences in circulating profiles of adiponectin and LCN2 between MA patients and healthy pregnant subjects. By contrast, circulating levels of FGF21 and FABP4 were significantly and independently elevated in patients with MA relative to control cases even after adjusting confounding factors (for FGF21: MA: 28.96 ± 2.17 ng/ml; HP: 19.18 ± 1.12 ng/ml, P Limitations, reasons for caution The study is limited by the sample size. In addition, our results were based-on Chinese population, whether it could be observed in other ethics group remain to be investigated. Meanwhile, the cause-effect relationship between increased serum FGF21 level and MA remains to be explored. Wider implications of the findings: Our data would suggest that serum levels of FGF21 and FABP4 are associated with MA. Moreover, circulating FGF21 levels may serve as a potential diagnostic biomarker for the recognition of M. Trial registration number IRB Ref. No.: KY201913

Development of liver fibrosis results in drastic changes in the liver microenvironment, which in turn accelerates disease progression. Although the pathological function of various hepatic cells in fibrogenesis is identified, the crosstalk between them remains obscure. The present study demonstrates that hepatic expression of adipocyte fatty acid binding protein (A‐FABP) is induced especially in the liver sinusoidal endothelial cells (LSECs) in mice after bile duct ligation (BDL). Genetic ablation and pharmacological inhibition of A‐FABP attenuate BDL‐ or carbon tetrachloride‐induced liver fibrosis in mice associating with reduced collagen accumulation, LSEC capillarization, and hepatic stellate cell (HSC) activation. Mechanistically, elevated A‐FABP promotes LSEC capillarization by activating Hedgehog signaling, thus impairs the gatekeeper function of LSEC on HSC activation. LSEC‐derived A‐FABP also acts on HSCs in paracrine manner to potentiate the transactivation of transforming growth factor β1 (TGFβ1) by activating c‐Jun N‐terminal kinase (JNK)/c‐Jun signaling. Elevated TGFβ1 subsequently exaggerates liver fibrosis. These findings uncover a novel pathological mechanism of liver fibrosis in which LSEC‐derived A‐FABP is a key regulator modulating the onset and progression of the disease. Targeting A‐FABP may represent a potential approach against liver fibrosis., Chronic liver injury upregulates adipocyte fatty acid binding protein (A‐FABP) in liver sinusoidal endothelial cells (LSECs). A‐FABP potentiates LSEC capillarization through activating Hh signaling, thus initiating hepatic stellate cell (HSC) activation. Moreover, LSEC‐derived A‐FABP stimulates TGFβ1 expression in HSCs through activating JNK/c‐Jun signaling. Enhanced TGFβ1 further perpetuates hepatic fibrogenesis.

Type 2 diabetes mellitus (T2DM) has become a global health problem with no cure. Despite lifestyle modifications and various pharmaceutical options, the achievement of stable and durable glucose control along with effective prevention of T2DM-related cardiovascular complications remains a challenging task in clinical management. With its selective high abundance in metabolic tissues (adipose tissue, liver, and pancreas), β-Klotho is the essential component of fibroblast growth factor (FGF) receptor complexes. It is essential for high-affinity binding of endocrine FGF19 and FGF21 to evoke the signaling cascade actively involved in homeostatic maintenance of glucose metabolism and energy expenditure. In this Review, we discuss the biological function of β-Klotho in the regulation of glucose metabolism and offer mechanistic insights into its involvement in the pathophysiology of T2DM. We review our current understanding of the endocrine axis comprised of β-Klotho and FGFs (FGF19 and FGF21) and its regulatory effects on glucose metabolism under physiological and T2DM conditions. We also highlight advances in the development and preclinical validation of pharmacological compounds that target β-Klotho and/or the β-Klotho-FGFRs complex for the treatment of T2DM. Given the remarkable advances in this field, we also discuss outstanding research questions and the many challenges in the clinical development of β-Klotho-based therapies.

Objective To investigate whether serum levels of fibroblast growth factor 21 (FGF21) and fatty acid-binding protein-4 (FABP4) are associated with missed abortion (MA) in humans. Design Cross-sectional study. Setting University-affiliated hospital. Patient(s) Patients with MA at 8–12 weeks of gestation. Intervention(s) None. Main Outcome Measures(s) Serum levels of FGF21 and FABP4 were tested by enzyme-linked immunosorbent assay. Placental samples were collected during dilation and curettage surgery, and the expression of FGF21 and its related genes were measured using quantitative polymerase chain reaction. Result(s) In the discovery cohort, 78 patients with MA and 79 healthy pregnant women matched for maternal age and body mass index were nested from a prospective cohort. Circulating levels of FGF21 and FABP4 were significantly and independently elevated in patients with MA relative to the levels in the healthy controls. A single measurement of FGF21 serum level effectively discriminated MA with an area under the receiver operating characteristics curve of 0.80 (95% confidence interval: 0.73–0.87). Importantly, in our external validation cohort that comprised subjects with MA (n = 34) or induced abortion (n = 27), the FGF21 serum levels achieved an area under the receiver operating characteristics curve of 0.85 (95% confidence interval: 0.75–0.96) when identifying those with MA. Nevertheless, expression of FGF21 in the placenta was not associated with its serum concentration. Placental tissues from patients with MA exhibited impaired FGF21 signaling. Conclusion(s) Our results suggested that serum levels of FGF21 and FABP4 were associated with MA. Circulating FGF21 may serve as a potential biomarker for the recognition of MA.

Diabetes mellitus (type 1 and type 2) and its various complications continue to place a huge burden on global medical resources, despite the availability of numerous drugs that successfully lower blood glucose levels. The major challenging issue in diabetes management is the prevention of various complications that remain the leading cause of diabetes-related mortality. Moreover, the limited long-term durability of monotherapy and undesirable side effects of currently used anti-diabetic drugs underlie the urgent need for novel therapeutic approaches. Phytochemicals represent a rich source of plant-derived molecules that are of pivotal importance to the identification of compounds with therapeutic potential. In this review, we aim to discuss recent advances in the identification of a large array of phytochemicals with immense potential in the management of diabetes and its complications. Given that metabolic inflammation has been established as a key pathophysiological event that drives the progression of diabetes, we focus on the protective effects of representative phytochemicals in metabolic inflammation. This paper also discusses the potential of phytochemicals in the development of new drugs that target the inflammation in the management of diabetes and its complications.

Background A growing body of evidence supports neutrophils as having an active role in the development of diabetic kidney disease (DKD). However, the clinical relevance of neutrophils and DKD in autoimmune diabetes remains unknown. This study aimed to investigate the relationship between circulating neutrophils and DKD in autoimmune diabetes. Methods Patients with type 1 diabetes (T1D, n = 226) and latent autoimmune diabetes in adults (LADA, n = 79) were enrolled and stratified according to the urinary albumin to creatinine ratio (ACR). Circulating levels of white blood cells (WBCs), including neutrophils, were measured in a central laboratory, and the neutrophil-to-lymphocyte ratio (NLR) was calculated. The risk factors associated with DKD were analysed by logistic regression. Results In T1D and LADA patients, the peripheral neutrophil counts increased in parallel with DKD advancement. The neutrophil counts in the patients with macroalbuminuria were significantly higher than those in the patients with normoalbuminuria for each type of diabetes. Furthermore, neutrophil counts positively correlated with ACR in T1D. In addition, neutrophils were independently associated with DKD in T1D in the logistic regression analysis, when various well-known risk factors, including age, gender, disease duration, hypertension, dyslipidemia and smoking status, were adjusted. Conclusions Neutrophil counts are closely associated with DKD in patients with autoimmune diabetes, suggesting that neutrophil-mediated inflammation may be involved in the pathogenesis of DKD in patients with autoimmune diabetes.

Persistent, unresolved inflammation in adipose tissue is a major contributor to obesity-associated metabolic complications. However, the molecular links between lipid-overloaded adipocytes and inflammatory immune cells in obese adipose tissues remain elusive. Here we identified adipocyte-secreted microRNA-34a (miR-34a) as a key mediator through its paracrine actions on adipose-resident macrophages. The expression of miR-34a in adipose tissues was progressively increased with the development of dietary obesity. Adipose-selective or adipocyte-specific miR-34a-KO mice were resistant to obesity-induced glucose intolerance, insulin resistance, and systemic inflammation, and this was accompanied by a significant shift in polarization of adipose-resident macrophages from proinflammatory M1 to antiinflammatory M2 phenotype. Mechanistically, mature adipocyte-secreted exosomes transported miR-34a into macrophages, thereby suppressing M2 polarization by repressing the expression of Krüppel-like factor 4 (Klf4). The suppressive effects of miR-34a on M2 polarization and its stimulation of inflammatory responses were reversed by ectopic expression of Klf4 in both bone marrow-derived macrophages and adipose depots of obese mice. Furthermore, increased miR-34a expression in visceral fat of overweight/obese subjects correlated negatively with reduced Klf4 expression, but positively with the parameters of insulin resistance and metabolic inflammation. In summary, miR-34a was a key component of adipocyte-secreted exosomal vesicles that transmitted the signal of nutrient overload to the adipose-resident macrophages for exacerbation of obesity-induced systemic inflammation and metabolic dysregulation.

Ethnopharmacological relevance FuFang ZhenZhu TiaoZhi (FTZ) is a hospitalized traditional Chinese medicine herbal formula with documented metabolic benefits. Polycystic ovary syndrome (PCOS) characterized by ovarian dysfunction and insulin resistance represents one of the most common endocrine disorders in close association with metabolic dysfunction in premenopausal women. Aim of The Study: The present study aimed to investigate the preventive effect of FTZ on letrozole-induced experimental PCOS and its associated insulin resistance in mice. Materials and methods Prepubertal female mice in the experimental groups (letrozole and FTZ) received continuous infusion of letrozole (50 μg/day) for 35 days. FTZ was administrated to mice by oral gavage daily at dosage of 2.892 g/kg body weight for 5 weeks. All groups of mice were fed a high-fat diet (HFD). Ovary and adipose tissue were collected from all mice after 5 weeks and adiponectin, testosterone, estradiol, and luteinizing hormone level determined. Results Letrozole-induced morphological changes in the ovary, including a decreased number of corpora lutea and antral follicles, and increased cystic follicles, were significantly attenuated in FTZ-treated mice. Additionally, FTZ treatment notably reversed PCOS-related disruption of estrous status. PCOS-related insulin resistance was markedly alleviated. Mechanistically, FTZ treatment notably enhanced circulating level and transcriptional abundance of adiponectin in adipose tissue, thereby orchestrating fat-ovary crosstalk. Conclusions Our data collectively demonstrate that FTZ exerted preventive benefits in an experimental model of PCOS, at least partially by potentiating the production of adiponectin from adipose tissues. This suggests that FTZ is a promising treatment for PCOS.

Additional file 2.

Background A growing body of evidence supports neutrophils as an active player in the development of diabetic kidney disease (DKD). However, the clinical relevance of neutrophils and DKD in autoimmune diabetes remains unknown. This study aims to investigate the relationship between circulating neutrophils and DKD in autoimmune diabetes.Methods Patients with type 1 diabetes (T1D, n=226) and latent autoimmune diabetes in adults (LADA, n=79) were enrolled and stratified according to the urinary albumin to creatinine ratio (ACR). Circulating levels of white blood cells (WBCs), including neutrophils, were measured in a central laboratory, and the neutrophil-to-lymphocyte ratio (NLR) was calculated. The risk factors associated with DKD were analysed by logistic regression.Results In T1D and LADA patients, the peripheral neutrophil counts increased in parallel with DKD advancement. The neutrophil counts in the patients with macroalbuminuria were significantly higher than those in the patients with normoalbuminuria for each type of diabetes. Furthermore, neutrophil counts positively correlated with the ACR. In addition, neutrophils were independently associated with DKD in T1D in the logistic regression analysis, when various well-known risk factors, including disease duration, sex, and smoking status, were adjusted as continuous variables.Conclusions Neutrophil counts are closely associated with DKD in patients with autoimmune diabetes, suggesting neutrophil-mediated inflammation may be involved in the pathogenesis of DKD in patients with autoimmune diabetes.

Background & Aims Inflammatory cell infiltration in the liver is a hallmark of non-alcoholic steatohepatitis (NASH). However, the pathological events which trigger the infiltration of inflammatory cells to mediate NASH pathogenesis remains poorly understood. This study aims to investigate the role of neutrophil-derived lipocalin 2 (LCN2) in mediating the transition from simple steatosis to NASH. Methods Animal models of NASH were induced by high fat high cholesterol (HFHC) diet and methionine- and choline-deficient (MCD) diet in LCN2 knockout mice and wild-type controls. Results Circulating levels of LCN2 and its hepatic expression were markedly increased in both murine models and human subjects with NASH, and these changes were associated with increased infiltration of neutrophils. In diet-induced NASH models, hepatic injury, necroinflammation and infiltration of neutrophils and macrophages were substantially attenuated by genetic depletion of LCN2. In contrast, chronic infusion of recombinant LCN2 exacerbated diet-induced liver injury, inflammation and macrophage accumulation in a neutrophil-dependent manner. Primary mouse neutrophils lacking LCN2 exhibited a defective migration capacity, which can be reversed by replenishment with recombinant LCN2. Mechanistically, LCN2 induced the expression of the chemokine (C-X-C motif) receptor 2 (CXCR2), thereby leading to activation of ERK1/2 and production of proinflammatory chemokines. LCN2-induced inflammation, infiltration of macrophages and liver injury was abrogated in CXCR2-deficient mice. Conclusions These findings demonstrated that LCN2 acts as a central mediator to facilitate the crosstalk between neutrophils and hepatic macrophages via induction of the chemokine receptor CXCR2, thereby exacerbating steatohepatitis. Lay summary Lipocalin-2 levels in blood and the liver were markedly increased in both mouse models and human subjects with NASH, and these changes were associated with increased infiltration of neutrophils in the liver. In diet-induced NASH models, hepatic injury, necroinflammation and infiltration of neutrophils and macrophages were substantially attenuated by genetic depletion of lipocalin-2, but was augmented by chronic infusion of recombinant lipocalin-2. Lipocalin-2 induced the expression of the chemokine receptor CXCR2, thereby leading to activation of the mitogen-activated protein (MAP) kinase ERK1/2 and production of proinflammatory chemokines. Lipocalin-2-induced inflammation, infiltration of macrophages and liver injury was abrogated in CXCR2-deficient mice.

Both atherosclerosis and obesity, an independent atherosclerotic risk factor, are associated with enhanced systemic inflammation. Obesity is also characterized by increased adipose tissue inflammation. However, the molecular mechanism underlying the accelerated atherosclerosis in obesity remains unclear. In obesity, activation of c-Jun N-terminal kinase (JNK) contributes to adipose tissue inflammation. The present study investigated whether the suppression of fat inflammation through adipose-specific JNK inactivation could protect against atherosclerosis in mice. ApoE−/− mice were cross-bred with transgenic mice with adipose-specific expression of a dominant negative form of JNK (dnJNK) to generate apoE−/−/dnJNK (ADJ) mice. ADJ mice treated with a high-fat–high-cholesterol diet exhibited significant attenuations of visceral fat and systemic inflammation without changes in lipid or glucose metabolism, and were protected against atherosclerosis, when compared with apoE−/− mice. Lean apoE−/− mice that received transplantation of visceral fat from obese wild-type donor mice for 4 weeks showed exacerbated systemic inflammation and atherosclerotic plaque formation. Conversely, apoE−/− recipients carrying a visceral fat graft from obese dnJNK donors were protected against enhanced systemic inflammation and atherogenesis. The beneficial effects of adipose-specific JNK inactivation on atherogenesis in apoE−/− recipients were significantly compromised by continuous infusion of recombinant adipocyte–fatty acid-binding protein (A-FABP), previously shown to interact with JNK via a positive feedback loop to modulate inflammatory responses. Together these data suggested that enhanced atherosclerosis in obesity can be attributed, at least in part, to a distant cross-talk between visceral fat and the vasculature, mediated by the release of proinflammatory cytokines, such as A-FABP, from the inflamed visceral adipose tissue with JNK activation.

Aim This study aimed to evaluate the relationship between serum uric acid (SUA) level and non-alcoholic fatty liver disease (NAFLD) in non-obese adults. Methods A cross-sectional study was carried out among 4098 adults, including 1936 non-obese and 2162 obese individuals. An additional 93 non-obese adults with biopsy-proven NAFLD were also included. Results The overall prevalence of NAFLD was 39.51% in the study group, and 14.88% in non-obese adults. The NAFLD patients had significantly higher SUA levels than controls in both men and women. The non-obese group had a higher NAFLD risk with increased SUA levels than the obese group, with odd ratios (95% confidence interval) of 2.559 (1.870–3.503) and 1.692 (1.371–2.087), respectively. In 93 non-obese adults with biopsy-proven NAFLD, SUA levels were significantly higher in those with non-alcoholic steatohepatitis. The prevalence of non-alcoholic steatohepatitis and lobule inflammation tended to increase to 57.58% and 66.67% as the SUA level increased to the fourth quartile. Subjects with hyperuricemia had significantly higher NAFLD activity scores and more serious lobule inflammation than the normal group. Conclusion Non-obese adults have higher NAFLD risk with increased SUA levels than obese individuals, and the inflammation progression of NAFLD is associated with increased SUA level in non-obese subjects.

Reactive oxygen species (ROS) regulate metabolism and chemical composition of various tissues. To understand how ROS affect the textural quality of fish muscle, we performed a multi-omics analysis on an established crisp grass carp model fed with a natural pro-oxidant faba bean. ROS levels were systemically and significantly increased up to three-fold in crisp grass carp, improving the muscle texture. Lipid metabolism was significantly enhanced up to five-fold in muscle and liver possibly to compensate the impaired carbohydrate metabolism of these tissues, but this caused further local ROS production. Mitochondrial damage associated with autophagy was evident in crisp grass carp. Proteomics revealed that elevated ROS likely disturbed the actin-myosin interaction and collagen turnover inducing fragmentation of myofibrillar proteins, all of which could have positively impacted the textural quality. The systemic metabolic changes that lead to the partial collapse of redox regulation likely underlie the ROS-induced improvement of textural quality.

Neutrophils infiltration in liver is one of the typical histological characteristics of nonalcoholic steatohepatitis (NASH) in both animal models and human subjects. This study was aimed to investigate the role of neutrophils in the process of NASH and its underling mechanisms. C57BL/6J mice were fed with either standard chow (SC) or methionine/choline-deficient (MCD) diet for 1, 2, 4, 8 weeks, respectively. C57BL/6J APOE(-/-) mice were fed with SC or high-fat high-cholesterol (HFHC) diet. Anti-Ly6G antibody was employed to deplete neutrophils and sivelestat was used to inhibit neutrophil elastase (NE). MCD-diet-receiving mice with neutrophil depletion had much lower serum ALT activity, liver inflammation, and mRNA levels of proinflammatory genes in the early stage of NASH (1 and 2 weeks) when compared to non-neutrophil-depleted mice. NE inhibitor sivelestat could recapitulate the effects of neutrophil depletion in APOE(-/-) mice fed with HFHC diet. As the disease progressed (4 and 8 weeks), neutrophil depletion did not lower serum ALT levels and liver lesions due to activation of Kupffer cells. Finally, we found neutrophils also affected anti-inflammation cytokine interleukin-1 receptor antagonist mRNA expression. Neutrophils play a crucial role in the early stage of NASH via NE.

Background Non-alcoholic fatty liver disease is an obesity-related chronic liver disorder ranging from simple steatosis to non-alcoholic steatohepatitis (NASH), which may progress to liver fibrosis and cirrhosis. Objective Tto investigate the role of Toll-like receptor (TLR) 4 in mediating the transition from steatosis to inflammation. Methods ApoE −/− /TLR4 mut mice and ApoE −/− /TLR4 wild-type mice (ApoE −/− /TLR4-WT) were generated by cross-breeding an ApoE-deficient (ApoE −/− ) strain with TLR4-mutant (TLR4 mut ) mice, which were fed with high-fat, high-cholesterol (HFHC) diet to induce obesity. Results ApoE −/− /TLR4-WT mice fed with an HFHC diet for 12 weeks developed typical pathological features of NASH, which is associated with obesity and the metabolic syndrome. By contrast, ApoE −/− /TLR4 mut mice lacking functional TLR4 were resistant to HFHC diet-induced liver inflammation and injury and were less susceptible to the diet-induced production of reactive oxygen species (ROS) and proinflammatory cytokines. In ApoE −/− /TLR4-WT mice, X-box binding protein-1 (XBP-1), a transcription factor involved in the unfolded protein responses, was activated in the liver by an HFHC diet, whereas XBP-1 activation was abrogated in ApoE −/− /TLR4 mut mice. In primary rat Kupffer cells, endotoxin induced XBP-1 activation through ROS production, whereas siRNA-mediated knockdown of XBP-1 expression resulted in a marked attenuation in endotoxin-evoked NF-κB activation and cytokine production. Furthermore, adenovirus-mediated expression of dominant negative XBP-1 led to a significant attenuation in HFHC diet-induced liver inflammation and injury in mice. Conclusions These findings support the key role of TLR4 in Kupffer cells in mediating the progression of simple steatosis to NASH, by inducing ROS-dependent activation of XBP-1.

Background/aims Hepatic fibrosis is a consequence of severe liver damage that occurs in many patients with chronic liver diseases. TCM 319 recipe is a Chinese Medicine formula which consists of six Chinese herbs. In this study, we investigated the anti-fibrotic efficacy and mechanisms of TCM 319 recipe. Methods Hepatic fibrosis in rats was induced by carbon tetrachloride (CCl4). 34 male adult SD rats were allocated into five groups (group 1-concomitant CCl4 and TCM 319 recipe for 8 weeks; group 2-CCl4 for 4 weeks and then CCl4 and TCM 319 recipe for 4 weeks; group 3-CCl4 alone for 8 weeks; group 4-TCM 319 recipe only for 8 weeks; group 5-untreated controls). After 8 weeks of treatment, serum ALT assay, liver tissue histological examination and immunostaining were carried out to examine the liver function and fibrosis degree. The expression levels of platelet derived growth factor (PDGF-B), PDGF-Rbeta, and transforming growth factor-beta 1 (TGF-beta1) were measured by quantitative RT-PCR and western blot. Results TCM 319 recipe reduced liver injury and attenuated hepatic fibrosis in group 1 compared with that in group 3. TCM 319 recipe suppressed the mRNA expression of tissue inhibitor of metalloproteinase 1 (TIMP-1). In addition, treatment with TCM 319 recipe significantly down-regulated mRNA expression of PDGF-B and PDGF-Rbeta, and it also suppressed protein expression of PDGF-Rbeta and TGF-beta1. Conclusions TCM 319 recipe extracts could attenuate hepatic fibrosis induced by CCl4 in rats. The anti-fibrotic effect of TCM 319 recipe is associated with the down-regulation of mRNA expression of TIMP-1, PDGF-B and PDGF-Rbeta, and with the suppression of protein expression of PDGF-Rbeta and TGF-beta1.

Hepatic ischemia/reperfusion (I/R) injury is a major cause of morbidity and mortality after liver surgery. Therefore, it is important to identity reliable biomarkers to assist early diagnosis of hepatic I/R injury. This study aimed to investigate the potential of serum levels of fibroblast growth factor 21 (FGF21) as a biomarker for hepatic I/R injury in patients with liver transplantation. Two independent cohorts of liver transplantation patients were recruited for determination of serum levels of FGF21, ALT and AST. The results demonstrated that serum FGF21 at 2 hours post-reperfusion in cohort-1 exhibited an approximately 20-fold elevation relative to those in healthy subjects. In blood samples dynamically collected in cohort-2, a dramatic increase in serum FGF21 levels (~25-fold) was observed at two hours after surgery, whereas the peak levels of serum ALT and AST were detected only after 24 hours. Temporal correlation analysis demonstrated a significant association of peak serum levels of FGF21 at 2 hours with the magnitude of the increase in both serum ALT and AST levels at 24 hours post transplantation. In conclusion, serum FGF21 may represent a sensitive and specific prognostic biomarker for early detection of I/R injury in patients with liver transplantation.

Among the 22 fibroblast growth factors (FGFs), FGF21 has now emerged as a key metabolic regulator. However, the mechanism whereby FGF21 mediates its metabolic actions per se remains largely unknown. Here, we show that FGF21 represses mammalian target of rapamycin complex 1 (mTORC1) and improves insulin sensitivity and glycogen storage in a hepatocyte-autonomous manner. Administration of FGF21 in mice inhibits mTORC1 in the liver, whereas FGF21-deficient mice display pronounced insulin-stimulated mTORC1 activation and exacerbated hepatic insulin resistance (IR). FGF21 inhibits insulin- or nutrient-stimulated activation of mTORC1 to enhance phosphorylation of Akt in HepG2 cells at both normal and IR condition. TSC1 deficiency abrogates FGF21-mediated inhibition of mTORC1 and augmentation of insulin signaling and glycogen synthesis. Strikingly, hepatic βKlotho knockdown or hepatic hyperactivation of mTORC1/ribosomal protein S6 kinase 1 abrogates hepatic insulin-sensitizing and glycemic-control effects of FGF21 in diet-induced insulin-resistant mice. Moreover, FGF21 improves methionine- and choline-deficient diet-induced steatohepatitis. Conclusions: FGF21 acts as an inhibitor of mTORC1 to control hepatic insulin action and maintain glucose homeostasis, and mTORC1 inhibition by FGF21 has the therapeutic potential for treating IR and type 2 diabetes. (Hepatology 2016;64:425-438)