Eplerenone ameliorates the phenotypes of metabolic syndrome with NASH in liver-specific SREBP-1c Tg mice fed high-fat and high-fructose diet

Impact of inflammation and anti-inflammatory modalities on diabetic cardiomyopathy healing: From fundamental research to therapy

Diabetic cardiomyopathy (DCM) is a prevalent cardiovascular complication of diabetes mellitus, characterized by high morbidity and mortality rates worldwide. However, treatment options for DCM remain limited. For decades, a substantial body of evidence has suggested that the inflammatory response plays a pivotal role in the development and progression of DCM. Notably, DCM is closely associated with alterations in inflammatory cells, exerting direct effects on major resident cells such as cardiomyocytes, vascular endothelial cells, and fibroblasts. These cellular changes subsequently contribute to the development of DCM. This article comprehensively analyzes cellular, animal, and human studies to summarize the latest insights into the impact of inflammation on DCM. Furthermore, the potential therapeutic effects of current anti-inflammatory drugs in the management of DCM are also taken into consideration. The ultimate goal of this work is to consolidate the existing literature on the inflammatory processes underlying DCM, providing clinicians with the necessary knowledge and tools to adopt a more efficient and evidence-based approach to managing this condition.

Therapies for patients with coexisting heart failure with reduced ejection fraction and non-alcoholic fatty liver disease

Heart failure with reduced ejection fraction (HFrEF) and nonalcoholic fatty liver disease (NAFLD) are two common comorbidities that share similar pathophysiological mechanisms. There is a growing interest in the potential of targeted therapies to improve outcomes in patients with coexisting HFrEF and NAFLD. This manuscript reviews current and potential therapies for patients with coexisting HFrEF and NAFLD. Pharmacological therapies, including angiotensin-converting enzyme inhibitors/angiotensin receptor blockers, mineralocorticoids receptor antagonist, and sodium-glucose cotransporter-2 inhibitors, have been shown to reduce fibrosis and fat deposits in the liver. However, there are currently no data showing the beneficial effects of sacubitril/valsartan, ivabradine, hydralazine, isosorbide nitrates, digoxin, or beta blockers on NAFLD in patients with HFrEF. This study highlights the importance of considering HFrEF and NAFLD when developing treatment plans for patients with these comorbidities. Further research is needed in patients with coexisting HFrEF and NAFLD, with an emphasis on novel therapies and the importance of a multidisciplinary approach for managing these complex comorbidities.

Positive selection of somatically mutated clones identifies adaptive pathways in metabolic liver disease

Somatic mutations in nonmalignant tissues accumulate with age and injury, but whether these mutations are adaptive on the cellular or organismal levels is unclear. To interrogate genes in human metabolic disease, we performed lineage tracing in mice harboring somatic mosaicism subjected to nonalcoholic steatohepatitis (NASH). Proof-of-concept studies with mosaic loss of Mboat7, a membrane lipid acyltransferase, showed that increased steatosis accelerated clonal disappearance. Next, we induced pooled mosaicism in 63 known NASH genes, allowing us to trace mutant clones side by side. This in vivo tracing platform, which we coined MOSAICS, selected for mutations that ameliorate lipotoxicity, including mutant genes identified in human NASH. To prioritize new genes, additional screening of 472 candidates identified 23 somatic perturbations that promoted clonal expansion. In validation studies, liver-wide deletion of Tbx3, Bcl6, or Smyd2 resulted in protection against hepatic steatosis. Selection for clonal fitness in mouse and human livers identifies pathways that regulate metabolic disease.

Positive selection of somatically mutated clones identifies adaptive pathways in metabolic liver disease

Somatic mutations in non-malignant tissues accumulate with age and insult, but whether these mutations are adaptive on the cellular or organismal levels is unclear. To interrogate mutations found in human metabolic disease, we performed lineage tracing in mice harboring somatic mosaicism subjected to non-alcoholic steatohepatitis (NASH). Proof-of-concept studies with mosaic loss of Mboat7 , a membrane lipid acyltransferase, showed that increased steatosis accelerated clonal disappearance. Next, we induced pooled mosaicism in 63 known NASH genes, allowing us to trace mutant clones side-by-side. This in vivo tracing platform, which we coined MOSAICS, selected for mutations that ameliorate lipotoxicity, including mutant genes identified in human NASH. To prioritize new genes, additional screening of 472 candidates identified 23 somatic perturbations that promoted clonal expansion. In validation studies, liver-wide deletion of Bcl6, Tbx3, or Smyd2 resulted in protection against NASH. Selection for clonal fitness in mouse and human livers identifies pathways that regulate metabolic disease.

Highlights

Mosaic Mboat7 mutations that increase lipotoxicity lead to clonal disappearance in NASH. In vivo screening can identify genes that alter hepatocyte fitness in NASH. Mosaic Gpam mutations are positively selected due to reduced lipogenesis. In vivo screening of transcription factors and epifactors identified new therapeutic targets in NASH.

Selenium-Enriched Probiotic Alleviates Western Diet-Induced Non-alcoholic Fatty Liver Disease in Rats via Modulation of Autophagy Through AMPK/SIRT-1 Pathway

Current study was aimed to investigate the ability of L.acidophilus SNZ 86 to biotransform inorganic selenium to a more active organic form, resulting in trace element enrichment. Selenium-enriched L. acidophilus SNZ 86 has been shown to be effective in the treatment of a variety of gastrointestinal illnesses, indicating the need for additional research to determine the full potential of this therapeutic strategy in the treatment of metabolic disorders. Herein, we employed the western style diet-induced model of non-alcoholic fatty liver disease (NAFLD) to explore the therapeutic effect of selenium-enriched probiotic (SP). Male Sprague Dawley rats (160-180 g) were fed a high-fat (58% Kcal of fat) and high-fructose (30% w/v) diet for 12 weeks to develop an animal model mimicking NAFLD. High-fat and High-fructose diet-fed rats exhibited hyperglycemia, hyperlipidemia, insulin resistance, abnormal liver function test, increased hepatic oxidative stress, and steatosis. SP was then administered orally (L acidophilus 1 × 10⁹ CFU/ml containing 0.4 g Se/day; p.o.) for 8 weeks. The selenium enrichment within L. acidophilus SNZ 86 was validated by TEM, which allowed for visualisation of the selenium deposition and size distribution in the probiotic. In NAFLD control rats, the expression of autophagy proteins (LC-3 A/B and Beclin), AMPK, and SIRT-1 was significantly reduced indicating downregulation of autophagy. However, supplementation of SP ameliorates hepatic steatosis as evidenced by improved biochemical markers and autophagic activation via upregulation of the AMPK and SIRT-1 pathway showing the relevance of autophagy in the disease aetiology. Collectively, these findings provide us with a better understanding of the role of SP in the treatment of hepatic steatosis and establish a therapeutic basis for potential clinical application of SP in the prevention of NAFLD and associated pathological conditions.

A transdermal treatment with MC903 ameliorates diet-induced obesity by reducing visceral fat and increasing myofiber thickness and energy consumption in mice

AIM

MC903 is a synthetic derivative of vitamin D3 that has been designed to diminish its impact on calcium metabolism and is clinically used as a transdermal reagent for psoriasis. Animal studies showed that an oral or intraperitoneal vitamin D3 treatment prevented the development of obesity. In contrast, the bioavailability of orally administered vitamin D3 is reported to be low in obese patients. In the current study, we aimed to investigate the impact of a transdermal treatment with MC903 in established obese mice. We further studied the underlying mechanisms of MC903-mediated metabolic improvement.

MATERIALS AND METHODS

Male C57BL/6 J mice were fed standard chow or a 60% high-fat diet (HFD) for 7 weeks, and a transdermal treatment with MC903 on the ear auricle was initiated thereafter. The metabolic profiles of mice were analyzed during 4 weeks of treatment, and mice were dissected for histological and gene expression analyses. The direct impacts of MC903 and vitamin D3 were investigated using 3T3-L1 adipocytes and C2C12 myotubes in vitro.

RESULTS

HFD-fed mice showed significant increases in body and epididymal white adipose tissue (eWAT) weights with enlarged adipocytes. They exhibited glucose intolerance, decreased oxygen consumption, and chronic inflammation in eWAT. The transdermal treatment with MC903 significantly ameliorated these metabolic abnormalities in HFD-fed mice without affecting food consumption. In accordance with enhanced energy metabolism, myofiber diameters and the expression of uncoupling protein 3 (UCP3) in the gastrocnemius and soleus muscle were significantly increased in MC903-treated HFD mice. In addition, vitamin D3 and MC903 both suppressed adipogenic differentiation and enhanced lipolysis in 3T3-L1 adipocytes, and increased UCP3 expression in cultured C2C12 myotubes. Furthermore, MC903 increased oxygen consumption and UCP3 knockdown significantly decreased them in C2C12 myotubes.

CONCLUSIONS

A transdermal treatment with MC903 increased myofiber diameter and energy metabolism and decreased visceral fat accumulation, thereby improving obesity and glucose intolerance in mice.

Secondary diabetes mellitus due to primary aldosteronism

Primary aldosteronism (PA) and diabetes mellitus (DM) are clinical conditions that increase cardiovascular risk. Approximately one in five patients with PA have DM. Nevertheless, the pathophysiology linking these two entities is not entirely understood. In addition, the majority of patients with PA have glucocorticoid co-secretion, which is associated with increased risk of impaired glucose homeostasis. In the present review, we aim to comprehensively discuss all the available research data concerning the interplay between mineralocorticoid excess and glucose metabolism, with separate analysis of the sequalae in muscle, adipose tissue, liver and pancreas. Aldosterone binds both mineralocorticoid and glucocorticoid receptors and amplifies tissue glucocorticoid activity, via 11-β-hydroxysteroid dehydrogenase type 1 stimulation. A clear classification of the molecular events as per specific receptor in insulin-sensitive tissues is impossible, while their synergistic interaction is plausible. Furthermore, aldosterone induces oxidative stress and inflammation, perturbs adipokine expression, thermogenesis and lipogenesis in adipose tissue, and increases hepatic steatosis. In pancreas, enhanced oxidative stress and inflammation of beta cells, predominantly upon glucocorticoid receptor activation, impair insulin secretion. No causality between hypokalemia and impaired insulin response is yet proven; in contrast, hypokalemia appears to be implicated with insulin resistance and hepatic steatosis. The superior efficacy of adrenalectomy in ameliorating glucose metabolism vs. mineralocorticoid receptor antagonists in clinical studies highlights the contribution of non-mineralocorticoid receptor-mediated mechanisms in the pathophysiologic process. The exact role of hypokalemia, the mechanisms linking mineralocorticoid excess with hepatic steatosis, and possible disease-modifying role of pioglitazone warrant further studies.

Involvement of the extracellular matrix and integrin signalling proteins in skeletal muscle glucose uptake

Whole-body euglycaemia is partly maintained by two cellular processes that encourage glucose uptake in skeletal muscle, the insulin- and contraction-stimulated pathways, with research suggesting convergence between these two processes. The normal structural integrity of the skeletal muscle requires an intact actin cytoskeleton as well as integrin-associated proteins, and thus those structures are likely fundamental for effective glucose uptake in skeletal muscle. In contrast, excessive extracellular matrix (ECM) remodelling and integrin expression in skeletal muscle may contribute to insulin resistance owing to an increased physical barrier causing reduced nutrient and hormonal flux. This review explores the role of the ECM and the actin cytoskeleton in insulin- and contraction-mediated glucose uptake in skeletal muscle. This is a clinically important area of research given that defects in the structural integrity of the ECM and integrin-associated proteins may contribute to loss of muscle function and decreased glucose uptake in type 2 diabetes.

Esaxerenone, a selective mineralocorticoid receptor blocker, improves insulin sensitivity in mice consuming high-fat diet

BACKGROUND

Esaxerenone is a novel, non-steroidal selective mineralocorticoid receptor (MR) blocker. MR activation plays a crucial role in the development of cardiovascular and metabolic diseases. In this study, we investigated the effects of esaxerenone on various metabolic parameters in mice.

MATERIALS AND METHODS

Esaxerenone (3 mg/kg/day) was orally administered to high-fat diet (HFD)-fed male C57BL/6 mice. Mice fed a normal diet (ND) served as controls. Glucose and insulin tolerance, plasma lipid levels, and transaminase levels were assessed as metabolic parameters. Macrophage accumulation in the adipose tissue was evaluated using histological analysis. 3T3-L1 adipocytes, HepG2 cells, and C2C12 myotubes were used for in vitro experiments. Gene expression and insulin signaling were examined using quantitative RT-PCR and western blotting, respectively.

RESULTS

HFD successfully induced insulin resistance compared with that in ND. Esaxerenone ameliorated insulin resistance (P < 0.05) without altering other metabolic parameters, such as the lipid profile. Esaxerenone administration tended to decrease plasma transaminase levels compared with those in the non-treated group. In the adipose tissue, esaxerenone decreased macrophage accumulation (P < 0.05) and increased the expression levels of adiponectin and PPARγ. Aldosterone significantly decreased the expression levels of PPARγ and adiponectin in 3T3-L1 adipocytes. Furthermore, aldosterone attenuated insulin-induced Akt phosphorylation in 3T3-L1 adipocytes, HepG2 cells, and C2C12 myotubes in a dose-dependent manner (P < 0.01). These effects were ameliorated by pretreatment with esaxerenone.

CONCLUSION

Esaxerenone ameliorated insulin resistance in HFD-fed mice. Reduction of inflammation and improvement in insulin signaling may underlie the beneficial effects of esaxerenone.

Integrated Liver and Plasma Proteomics in Obese Mice Reveals Complex Metabolic Regulation

Obesity leads to the development of nonalcoholic fatty liver disease (NAFLD) and associated alterations to the plasma proteome. To elucidate the underlying changes associated with obesity, we performed liquid chromatography-tandem mass spectrometry in the liver and plasma of obese leptin-deficient ob/ob mice and integrated these data with publicly available transcriptomic and proteomic datasets of obesity and metabolic diseases in preclinical and clinical cohorts. We quantified 7173 and 555 proteins in the liver and plasma proteomes, respectively. The abundance of proteins related to fatty acid metabolism were increased, alongside peroxisomal proliferation in ob/ob liver. Putatively secreted proteins and the secretory machinery were also dysregulated in the liver, which was mirrored by a substantial alteration of the plasma proteome. Greater than 50% of the plasma proteins were differentially regulated, including NAFLD biomarkers, lipoproteins, the 20S proteasome, and the complement and coagulation cascades of the immune system. Integration of the liver and plasma proteomes identified proteins that were concomitantly regulated in the liver and plasma in obesity, suggesting that the systemic abundance of these plasma proteins is regulated by secretion from the liver. Many of these proteins are systemically regulated during type 2 diabetes and/or NAFLD in humans, indicating the clinical importance of liver-plasma cross talk and the relevance of our investigations in ob/ob mice. Together, these analyses yield a comprehensive insight into obesity and provide an extensive resource for obesity research in a prevailing model organism.

Relationship of Nonalcoholic Fatty Liver Disease and Heart Failure With Preserved Ejection Fraction

Although there is an established bidirectional relationship between heart failure with reduced ejection fraction and liver disease, the association between heart failure with preserved ejection fraction (HFpEF) and liver diseases, such as nonalcoholic fatty liver disease (NAFLD), has not been well explored. In this paper, the authors provide an in-depth review of the relationship between HFpEF and NAFLD and propose 3 NAFLD-related HFpEF phenotypes (obstructive HFpEF, metabolic HFpEF, and advanced liver fibrosis HFpEF). The authors also discuss diagnostic challenges related to the concurrent presence of NAFLD and HFpEF and offer several treatment options for NAFLD-related HFpEF phenotypes. The authors propose that NAFLD-related HFpEF should be recognized as a distinct HFpEF phenotype.

Efficacy and safety of apararenone (MT-3995) in patients with nonalcoholic steatohepatitis: A randomized controlled study

AIM

To evaluate the efficacy, safety, and tolerability of apararenone 10 mg/day in patients with nonalcoholic steatohepatitis (NASH).

METHODS

In this multicenter, randomized, double-blind, placebo-controlled phase II study, patients received apararenone 10 mg or placebo once daily for 72 weeks. The primary efficacy end-point was percent change in serum alanine aminotransferase (ALT) from baseline to 24 weeks after randomization. Secondary efficacy end-points included changes in liver fibrosis markers. Adverse drug reactions (ADRs) and serum potassium levels were evaluated.

RESULTS

Forty-eight patients were randomly assigned to treatment (placebo, 23; apararenone, 25). The percent change in ALT at 24 weeks was -3.0% and -13.7% with placebo and apararenone, respectively (p = 0.308). The apararenone group showed greater reductions from baseline in fibrosis markers (type IV collagen 7S and procollagen-3 N-terminal peptide) and noninvasive tests of fibrosis (enhanced liver fibrosis score and Fibrosis-4 index) at all time points versus placebo. The percentage of patients with improvement of 1 point or more in fibrosis stage/without nonalcoholic fatty liver disease activity score worsening was 41.7% with apararenone and 26.1% with placebo (p = 0.203). Adverse drug reactions were reported in three (13.0%) and three (12.5%) patients in the placebo and apararenone groups, respectively. Serum potassium levels increased in the apararenone group during the study and decreased to near baseline after the end of treatment.

CONCLUSIONS

In patients with NASH, apararenone 10 mg/day for 72 weeks was effective in decreasing ALT levels, improved multiple potential fibrosis markers, and was safe and well tolerated. Pathological findings showed anti-inflammatory and antifibrotic effects of apararenone.

Inhibition of Col6a5 Improve Lipid Metabolism Disorder in Dihydrotestosterone-Induced Hyperandrogenic Mice

Hyperandrogenism is a key pathological feature of polycystic ovarian syndrome (PCOS). Excess androgen can lead to PCOS-like cell hypertrophy in the ovaries and adipose tissue of rodents. Here, we established a dihydrotestosterone (DHT)-induced hyperandrogenic mouse model to analyze the differences in gene expression and signaling pathways of the ovaries and gonad fat pads of mice treated with or without DHT by RNA microarray analysis. From the results, we focused on the overlapping differentially expressed gene—Col6a5—and the major differentially enriched signaling pathway—lipid metabolism. We employed DHT-induced mouse ovarian stromal cell, adipogenic 3T3-L1 cell and hepatic cell line NCTC1469 models to investigate whether androgens directly mediate lipid accumulation and hypertrophy. We found that DHT increased lipid droplet accumulation in ovarian stromal cells and adipogenic 3T3-L1 cells but not NCTC1469 cells. DHT significantly altered stromal cell cholesterol metabolism and steroidogenesis, as indicated by changes in cholesterol levels and the expression of related genes, but these effects were not observed in 3T3-L1 cells. Moreover, Col6a5 expression was significantly increased in ovaries and gonadal fat pads of DHT-treated mice, and Col6a5 inhibition alleviated DHT-induced excess lipid accumulation and hypertrophy of ovarian stromal cells and adipogenic 3T3-L1 cells, even improved lipid metabolism in overnourished NCTC1469 cells. Our results indicate that Col6a5 plays important roles in the pathogenesis of DHT-induced lipid metabolism disorder and the hypertrophy of ovarian stromal cells and adipocytes.

Role of Steroid Hormones in the Pathogenesis of Nonalcoholic Fatty Liver Disease

Nonalcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease and may progress to cirrhosis or even hepatocellular carcinoma. A number of steroid hormones are important regulators of lipid homeostasis through fine tuning the expression of genes related to lipid synthesis, export, and metabolism. Dysregulation of such pathways has been implicated in the pathogenesis of NAFLD. The aim of this review is to clarify the potential impact of steroid hormones on NAFLD. We also highlight potential interventions through modulating steroid hormone levels or the activities of their cognate receptors as therapeutic strategies for preventing NAFLD.

From Liver Fat to Cancer: Perils of the Western Diet

Hepatocellular carcinoma (HCC), the most common type of primary liver cancer provides the prototypical example of an obesity-related cancer. The obesity epidemic gave rise to an enormous increase in the incidence of non-alcoholic fatty liver disease (NAFLD), a condition that affects one third of American adults. In about 20% of these individuals, simple liver steatosis (hepatosteatosis) progresses to non-alcoholic steatohepatitis (NASH) characterized by chronic liver injury, inflammation, and fibrosis. In addition to liver failure, NASH greatly increases the risk of HCC. Here we discuss the metabolic processes that control the progression from NAFLD to NASH and from NASH to HCC, with a special emphasis on the role of free-non-esterified cholesterol in the process.

The mineralocorticoid receptor-an emerging player in metabolic syndrome?

Metabolic syndrome is a cluster of conditions that increase the risk of cardiovascular diseases, and comprises obesity, hypertension, impaired glucose metabolism and dyslipidaemia. It is well recognised that the mineralocorticoid receptor (MR) plays an important role in blood pressure regulation via its effect on salt and water retention in renal tubules, with hypertension being a key feature in primary aldosteronism patients with excess adrenal production of aldosterone, the primary ligand for MRs in the epithelial tissues. MRs are also expressed in a number of non-epithelial tissues including adipose tissue; in these tissues, glucocorticoids or cortisol can also activate MRs due to low levels of 11-beta-hydroxysteroid-dehydrogenase type 2 (11-βHSD2), the enzyme which inactivates cortisol. There is increasing evidence suggesting that over-activation of MRs plays a role in the pathophysiology of the other components of metabolic syndrome, promoting adiposity, inflammation and glucose intolerance, and that MR antagonists may confer beneficial effects on energy and substrate homeostasis and cardiometabolic diseases. This review discusses the advances in the literature shedding light on the MR as an emerging player in metabolic syndrome.

In Vitro and In Vivo Models of Non-Alcoholic Fatty Liver Disease: A Critical Appraisal

Non-alcoholic fatty liver disease (NAFLD), including non-alcoholic fatty liver (NAFL) and non-alcoholic steatohepatitis (NASH), represents the hepatic manifestation of obesity and metabolic syndrome. Due to the spread of the obesity epidemic, NAFLD is becoming the most common chronic liver disease and one of the principal indications for liver transplantation. However, no pharmacological treatment is currently approved to prevent the outbreak of NASH, which leads to fibrosis and cirrhosis. Preclinical research is required to improve our knowledge of NAFLD physiopathology and to identify new therapeutic targets. In the present review, we summarize advances in NAFLD preclinical models from cellular models, including new bioengineered platforms, to in vivo models, with a particular focus on genetic and dietary mouse models. We aim to discuss the advantages and limits of these different models.

A Mineralocorticoid Receptor Deficiency in Myeloid Cells Reduces Liver Steatosis by Impairing Activation of CD8+ T Cells in a Nonalcoholic Steatohepatitis Mouse Model

Background and Aims

The mineralocorticoid receptor (MR) and renin-angiotensin-aldosterone system (RAAS) are implicated in non-alcoholic liver fatty disease (NALFD). However, inflammatory mechanisms linking MR and RAAS with disease pathology remain unclear. Here we aimed to evaluate the contribution of myeloid MR to the inflammatory response in an animal model of non-alcoholic steatohepatitis (NASH), induced with a methionine-choline deficient diet (MCD).

Methods

Mice with a conditional deficiency of MR in myeloid cells (MyMRKO) and their counterpart floxed control mice (FC) were fed for 18 days with MCD or chow diet, respectively. Serum levels of aminotransferases and aldosterone levels were measured and hepatic steatosis, inflammation and fibrosis scored histologically. Hepatic triglyceride content (HTC) and hepatic mRNA levels of pro-inflammatory pro-fibrotic-associated genes were also assessed. Deep flow cytometric analysis was used to dissect the immune response during NASH development.

Results

MyMRKO mice fed with an MCD diet exhibited reduced hepatic inflammation and lower HTC than controls. Absolute number and percentage of liver inflammatory infiltrate cells (except for CD8⁺ T lymphocytes) were similar in both MyMRKO and control mice fed with an MCD diet but expression of the costimulatory molecule CD86 by dendritic cells and the CD25 activation marker in CD8⁺ T cells were significantly reduced in MyMRKO.

Conclusions

Proinflammatory cells are functionally suppressed in the absence of MR. We hypothesized that loss of MR in myeloid cells reduces lipid accumulation in the liver, in part through modulating the adaptive immune response, which is pivotal for the development of steatosis.

Drug-Drug Interactions of the Nonsteroidal Mineralocorticoid Receptor Antagonist Apararenone With Midazolam, Warfarin, and Digoxin: A Phase 1 Studies in Healthy Volunteers

PURPOSE

To characterize the clinical relevance of in vitro drug-drug interaction findings with apararenone (MT-3995), the effects of apararenone on the sensitive substrates of cytochrome P450 3A4 (midazolam) and 2C9 (warfarin), and P-glycoprotein (digoxin), were assessed through a series of studies conducted in healthy volunteers.

METHODS

Three studies were conducted in 56 healthy adults. Study 1 investigated the effects of the administration of apararenone with midazolam; apararenone was administered on days 2 (320 mg) and days 3-15 (20 mg/d), and midazolam 2 mg, on days 1 and 15. Study 2 investigated the effects of the administration of apararenone with warfarin; apararenone was administered on days 8-11 (40 mg/d) and days 12-27 (10 mg/d), and warfarin 25 mg, on days 1 and 21. Study 3 assessed the effects of the administration of apararenone with digoxin; apararenone was administered on days 11 (160 mg) and days 12-28 (10 mg/d), and digoxin 0.5 mg, on days 1 and 24. Pharmacokinetic parameters included C_max, AUC_0-t, and AUC_0-∞. The safety profile was evaluated based on adverse events from spontaneous reports and clinical findings.

FINDINGS

After the administration of midazolam together with apararenone, compared with midazolam alone, the midazolam ± apararenone treatment ratios (90% CIs) of the geometric least squares (LS) mean C_max, AUC_0-t, and AUC_0-∞ values were 1.263 (1.147-1.392), 1.342 (1.220-1.477), and 1.370 (1.225-1.534), respectively. After the administration of warfarin ± apararenone, the R-warfarin ± apararenone treatment ratios (90% CIs) of the geometric LS mean C_max, AUC_0-t, and AUC_0-∞ values were 1.008 (0.934-1.089), 1.078 (1.029-1.129), and 1.110 (1.056-1.166). Corresponding values for S-warfarin were 1.025 (0.941-1.117), 1.024 (0.979-1.071), and 1.031 (0.984-1.080). After the administration of digoxin ± apararenone, the digoxin ± apararenone treatment ratios (90% CIs) of the geometric LS mean C_max, AUC_0-t, and AUC_0-∞ values were 0.929 (0.789-1.093), 0.894 (0.797-1.033), and 0.887 (0.805-0.977), respectively. Treatment-emergent adverse events were generally of mild to moderate intensity, and no serious adverse events of any kind were reported.

IMPLICATIONS

The findings from this analysis of data from healthy volunteers suggest minimal risk for potential drug-drug interactions between apararenone and other drugs that are likely to be used concurrently in patients. ClinicalTrials.gov identifier: NCT02531568.

Significance of MR/OPN/HMGB1 axis in NAFLD-associated hepatic fibrogenesis

AIMS

The activation of hepatic stellate cells (HSCs) plays a central role in liver fibrosis, however non-alcoholic fatty liver disease (NAFLD) associated liver fibrogenesis have been poorly understood. We aimed to determine the significance of mineralocorticoid receptor (MR)/osteopontin (OPN)/high-mobility group box-1 (HMGB1) axis in this setting.

MAIN METHODS

Liver specimens were collected from NAFLD patients and murine NAFLD models established with 12-week high fat diet (HFD) for analysis of both upstream signals of MR and intrahepatic MR/OPN/HMGB1 axis. The in vitro cell model of NAFLD-associated liver fibrogenesis was established by treating LX-2 (a cell line of human HSCs) with free fatty acids (FFA). The effects of MR signaling were evaluated using with ALD (MR activator) or eplerenone (Ep, MR antagonist). Moreover, the in vitro loss- and gain- of function approaches were applied to confirm the upstream and downstream relationships of mediators contained in the intracellular MR/OPN/HMGB1 axis of LX-2.

KEY FINDINGS

In NAFLD condition, both human and mouse liver tissue samples demonstrated a significant up-regulation of MR/OPN/HMGB1 axis simultaneously with enhanced expression of pro-fibrogenic markers, including ACTA2, TIMP1, TGFB1 and COL1A1. Besides, enhanced production of serum aldosterone (ALD) was also observed in mouse NAFLD models. Moreover, the in vitro data demonstrated MR play an essential role in FFA-induced HSCs fibrogenesis. Meanwhile, MR acts as the upstream effector mediator of OPN and shares downstream HMGB1 with OPN.

SIGNIFICANCE

The MR/OPN/HMGB1 axis could be therapeutically targeted to treat NAFLD associated hepatic fibrogenesis.

Current and emerging pharmacological options for the treatment of nonalcoholic steatohepatitis

Nonalcoholic fatty liver disease (NAFLD) is a highly prevalent disease and important unmet medical need. Current guidelines recommend, under specific restrictions, pioglitazone or vitamin E in patients with NASH and significant fibrosis, but the use of both remains off-label. We summarize evidence on medications for the treatment of nonalcoholic steatohepatitis (NASH), since NASH has been mainly associated with higher morbidity and mortality. Some of these medications are currently in phase 3 clinical trials, including obeticholic acid (a farnesoid X receptor agonist), elafibranor (a peroxisome proliferator activated receptor [PPAR]-α/δ dual agonist), cenicriviroc (a CC chemokine receptor antagonist), MSDC-0602 K (a PPAR sparing modulator), selonsertib (an apoptosis signal-regulating kinase-1 inhibitor) and resmetirom (a thyroid hormone receptor agonist). A significant research effort is also targeting PPARs and selective PPAR modulators, including INT131 and pemafibrate, with the expectation that novel drugs may have beneficial effects similar to those of pioglitazone, but without the associated adverse effects. Whether these and other medications could offer tangible therapeutic benefits, alone or in combination, apparently on a background of lifestyle modification, i.e. exercise and a healthy dietary pattern (e.g. Mediterranean diet) remain to be proven. In conclusion, major advances are expected for the treatment of NASH.

Oxymatrine alleviated hepatic lipid metabolism via regulating miR-182 in non-alcoholic fatty liver disease

AIMS

This study aimed to investigate oxymatrine via regulating miR-182 improved the hepatic lipid accumulation in non-alcoholic fatty liver disease (NAFLD) model.

MATERIALS AND METHODS

Wistar rats were fed high-fat and high-fructose diet (HFDHFr group) for 4 weeks and HepG2 cells were treated with palmitic acid (PA group), and then were given oxymatrine intervention. The expression profiles of miRNAs were accessed by RNA sequencing (RNA-Seq). Hematoxylin-eosin (HE) staining and Oil Red O staining were used to observe the inflammation and lipid accumulation in liver. The levels of sterol regulatory element binding protein-1c (SREBP-1c), acetyl-CoA carboxylase (ACC), fatty-acid synthase (FAS) and carnitine palmitoyltransferase 1A (CPT-1A) were detected by RT-qPCR and Western blotting, respectively. Cell viability was detected by Cell Counting Kit-8 (CCK-8).

KEY FINDINGS

miR-182 was down-regulated in the HFDHFr group and PA group. Oxymatrine reduced body weight, and improved glucose tolerance and insulin resistance in the HFDHFr + OMT group compared with HFDHFr group. In addition, oxymatrine reduced the ratio (liver weight/body weight), the content of triglycerides (TG), hepatic lipid accumulation and steatosis. The levels of SREBP-1c, ACC, and FAS were significantly decreased, while the CPT-1A level was obviously elevated after oxymatrine intervention (P < 0.05). In vivo, miR-182 knockdown increased the levels of SREBP-1c, ACC and FAS, while reduced the CPT-1A level. Additionally, oxymatrine attenuated the effects of miR-182 inhibitor on lipid accumulation.

SIGNIFICANCE

We presented a possible mechanism that oxymatrine alleviated hepatic lipid metabolism via regulating miR-182 in NAFLD model.

[Role of Angiogenesis and Chronic Inflammation in Fat Hypertrophy in NASH Pathology]

Tissue expansion and chronic inflammation in adipose tissue (AT) are closely related to nonalcoholic steatohepatitis (NASH) pathology. Angiogenesis is initiated by the detachment of pericytes (PCs) from vessels in AT. This process is necessary for the development of AT in obesity. The detachment is caused by excessive platelet-derived growth factor B (PDGF-B) derived from M1-macrophages (Mφ) infiltrating obese AT. On the other hand, AT of tamoxifen-induced systemic PDGF receptor-β knockout mice showed decreased detachment of PCs from vessels in obesity, thereby attenuating hypertrophy of AT mediated by neoangiogenesis, resulting in protection from the development of chronic AT inflammation and systemic insulin resistance. The selective mineralocorticoid receptor (MR) inhibitor eplerenone (Ep) suppresses chronic inflammation in fat and the liver, improves glucose and lipid metabolism, and inhibits body weight and fat mass gain in mice fed a high-fat diet. As a novel mechanism, Ep increases energy expenditure and suppresses fat accumulation, thereby controlling the polarity of visceral AT Mφ from inflammatory M1 to anti-inflammatory M2 dominant. In addition, Ep directly inhibits the activation of signals 1 and 2 of NLRP3-inflammasomes in Mφ, which is an inflammatory mechanism closely involved in the development of NASH. Thus, we propose novel therapeutic approaches to NASH. Inhibition of PDGF receptor-β signaling prevents AT hypertrophy by regulating AT angiogenesis, and MR inhibitors directly suppress chronic inflammation in the AT and liver.

Role of Mineralocorticoid Receptor in Adipogenesis and Obesity in Male Mice

Increased visceral adiposity and hyperglycemia, 2 characteristics of metabolic syndrome, are also present in conditions of excess glucocorticoids (GCs). GCs are hormones thought to act primarily via the glucocorticoid receptor (GR). GCs are commonly prescribed for inflammatory disorders, yet their use is limited due to many adverse metabolic side effects. In addition to GR, GCs also bind the mineralocorticoid receptor (MR), but there are many conflicting studies about the exact role of MR in metabolic disease. Using MR knockout mice (MRKO), we find that both white and brown adipose depots form normally when compared with wild-type mice at P5. We created mice with adipocyte-specific deletion of MR (FMRKO) to better understand the role of MR in metabolic dysfunction. Treatment of mice with excess GCs for 4 weeks, via corticosterone in drinking water, induced increased fat mass and glucose intolerance to similar levels in FMRKO and floxed control mice. Separately, when fed a high-fat diet for 16 weeks, FMRKO mice had reduced body weight, fat mass, and hepatic steatosis, relative to floxed control mice. Decreased adiposity likely resulted from increased energy expenditure since food intake was not different. RNA sequencing analysis revealed decreased enrichment of genes associated with adipogenesis in inguinal white adipose of FMRKO mice. Differentiation of mouse embryonic fibroblasts (MEFs) showed modestly impaired adipogenesis in MRKO MEFs compared with wild type, but this was rescued upon the addition of peroxisome proliferator-activated receptor gamma (PPARγ) agonist or PPARγ overexpression. Collectively, these studies provide further evidence supporting the potential value of MR as a therapeutic target for conditions associated with metabolic syndrome.

The Race to Bash NASH: Emerging Targets and Drug Development in a Complex Liver Disease

Nonalcoholic steatohepatitis (NASH) is a severe form of nonalcoholic fatty liver disease (NAFLD) characterized by liver steatosis, inflammation, and hepatocellular damage. NASH is a serious condition that can progress to cirrhosis, liver failure, and hepatocellular carcinoma. The association of NASH with obesity, type 2 diabetes mellitus, and dyslipidemia has led to an emerging picture of NASH as the liver manifestation of metabolic syndrome. Although diet and exercise can dramatically improve NASH outcomes, significant lifestyle changes can be challenging to sustain. Pharmaceutical therapies could be an important addition to care, but currently none are approved for NASH. Here, we review the most promising targets for NASH treatment, along with the most advanced therapeutics in development. These include targets involved in metabolism (e.g., sugar, lipid, and cholesterol metabolism), inflammation, and fibrosis. Ultimately, combination therapies addressing multiple aspects of NASH pathogenesis are expected to provide benefit for patients.

Nuciferine Prevents Hepatic Steatosis by Regulating Lipid Metabolismin Diabetic Rat Model

Objective

This study investigatesthe nuciferine capacity to regulate the liver’s lipid metabolism regarding steatosis and injury in STZ-induced diabetic rats.

Materials and Methods

The rats were randomly divided into groups control, diabetic and nuciferine 200 mg/kg/ day treatment. After 4 days of STZ injection, the nuciferine group was treated and administered via oral gavages for 4 weeks. At the end of experiment, blood, liver, myocardial and muscular samples were collected.

Results

Nuciferine-treated significantly increased the body weight from 339.4g to 367.8g, but significantly decreased the food and water intake compared with diabetic rats. Also, the nuciferine-treated rats had significantly decreased TC, TG, and FFAs in the liver compared with the diabetic group, especially the serum markers of blood glucose. These were associated with the gene expression related to lipogenesis which was significantly down-regulated; the gene expression involved in lipolysis and fatty acid β-oxidation was significantly up-regulated. Discussion and

Conclusion

The data provide evidence that nuciferine supplementation could protect the liver by regulating lipid metabolism gene expression resulting in decreasing the steatosis and injury in diabetic rat. Thus, nuciferine could be developed as a diabetic adjuvant food additive in future.

Effect of the mineralocorticoid receptor antagonist eplerenone on liver fat and metabolism in patients with type 2 diabetes: A randomized, double-blind, placebo-controlled trial (MIRAD trial)

AIM

To investigate whether the mineralocorticoid receptor antagonist eplerenone has beneficial effects on liver fat and metabolism in patients with type 2 diabetes (T2D), the mineralocorticoid receptor antagonist in type 2 diabetes (MIRAD) trial.

MATERIAL AND METHODS

In this 26-week, double-blind, randomized, placebo-controlled trial, we enrolled 140 patients with T2D and high risk of cardiovascular disease. Patients were randomized 1:1 to either eplerenone with a target dose of 200 mg/day for patients with estimated glomerular filtration rate (eGFR) of 60 mL/min per 1.73 m² or more and 100 mg/day for patients with eGFR between 41 and 59 mL/min per 1.73 m² or placebo. The primary outcome measure was change in liver fat by proton magnetic resonance spectroscopy at week 26 from baseline; secondary outcomes were changes in metabolism, and safety by incident hyperkalaemia.

RESULTS

No changes in liver fat in the eplerenone group 0.91% (95% CI -0.57 to 2.39) or the placebo group -1.01% (-2.23 to 0.21) were found. The estimated absolute treatment difference was 1.92% (-3.81 to 0.01; P = 0.049). There was no beneficial impact on supporting secondary outcome variables of metabolism as fat mass distribution, lipid metabolism or insulin resistance. Despite a high dosage of eplerenone 164 versus 175 mg in patients treated with placebo (P = 0.228), the number of patients with incident hyperkalaemia (≥5.5 mmol/L) was low, with six in the eplerenone versus two in the placebo group (P = 0.276).

CONCLUSION

The addition of high doses of eplerenone to background antidiabetic and antihypertensive therapy does not show beneficial effects on liver fat and metabolism in patients with T2D.

Insulin-like growth factor binding protein 7 accelerates hepatic steatosis and insulin resistance in non-alcoholic fatty liver disease

An association between increased insulin-like growth factor binding protein-7 (IGFBP7) expression and insulin resistance in metabolic diseases has been reported. However, the role and molecular mechanism of IGFBP-7 in non-alcoholic fatty liver disease (NAFLD) remains largely unknown. Therefore, the potential function of IGFBP7 in the pathological progression of NAFLD was explored in this investigation. For in vivo experiments, an animal model of NAFLD was established in C57BL/6 mice by feeding a high-fat diet (HFD), and IGFBP7 was knocked down by injecting adeno-associated adenovirus (AAV)-mediated short-hairpin (sh)-IGFBP7 into the liver. We found that AAV-sh-IGFBP7 treatment significantly alleviated hepatocyte injury and inhibited hepatic lipid accumulation by reducing lipogenesis-associated gene expression. Furthermore, downregulation of IGFBP7 markedly ameliorated IR and restored impaired insulin signalling by elevating the phosphorylation levels of IRS-1, Akt and GSK3β in HFD-treated mice. Similar results were also confirmed by an in vitro study in a palmitic acid (PA)-stimulated HepG2 cell model. In conclusion, our study demonstrates that IGFBP7 contributes to hepatic steatosis and insulin resistance in NAFLD development, which might serve as a novel therapeutic agent for the treatment of NAFLD.

Metabolic Targets in Nonalcoholic Fatty Liver Disease

The prevalence and diagnosis of nonalcoholic fatty liver disease (NAFLD) is on the rise worldwide and currently has no FDA-approved pharmacotherapy. The increase in disease burden of NAFLD and a more severe form of this progressive liver disease, nonalcoholic steatohepatitis (NASH), largely mirrors the increase in obesity and type 2 diabetes (T2D) and reflects the hepatic manifestation of an altered metabolic state. Indeed, metabolic syndrome, defined as a constellation of obesity, insulin resistance, hyperglycemia, dyslipidemia and hypertension, is the major risk factor predisposing the NAFLD and NASH. There are multiple potential pharmacologic strategies to rebalance aspects of disordered metabolism in NAFLD. These include therapies aimed at reducing hepatic steatosis by directly modulating lipid metabolism within the liver, inhibiting fructose metabolism, altering delivery of free fatty acids from the adipose to the liver by targeting insulin resistance and/or adipose metabolism, modulating glycemia, and altering pleiotropic metabolic pathways simultaneously. Emerging data from human genetics also supports a role for metabolic drivers in NAFLD and risk for progression to NASH. In this review, we highlight the prominent metabolic drivers of NAFLD pathogenesis and discuss the major metabolic targets of NASH pharmacotherapy.

Links between aldosterone excess and metabolic complications: A comprehensive review

Shortly after the first description of primary aldosteronism (PA) appeared in the 1950s by Jerome Conn, an association of the condition with diabetes mellitus was documented. However, a clear pathophysiological interrelationship linking the two entities has yet to be established. Nevertheless, so far, many mechanisms contributing to insulin resistance and dysregulation of glucose uptake have been described. At the same time, many observational studies have reported an increased prevalence of the metabolic syndrome (MetS) among patients with PA. Regarding the relationship between aldosterone levels and obesity, a vicious cycle of adipokine-induced aldosterone production and aldosterone adipogenic action may be further contributing to MetS manifestations in PA patients. However, whether aldosterone excess affects lipid metabolism is still under investigation. Also, recent findings of the coexistence of glucocorticoid excess in many cases of PA highlight the need for further studies to examine the presumed link between high aldosterone levels and various metabolic parameters. In the present review, our focus is to comprehensively present the spectrum of available research findings concerning the possible associations between aldosterone excess and metabolic alterations, including impaired glucose metabolism, insulin resistance and, consequently, diabetes, altered lipid metabolism and the development of fatty liver. In addition, the complex relationship between obesity and aldosterone is discussed in detail.

Spironolactone in Combination with α-glycosyl Isoquercitrin Prevents Steatosis-related Early Hepatocarcinogenesis in Rats through the Observed NADPH Oxidase Modulation

Administration of the diuretic, spironolactone (SR), can inhibit chronic liver diseases. We determined the effects of SR alone or in combination with the antioxidant α-glycosyl isoquercitrin (AGIQ) on hyperlipidemia- and steatosis-related precancerous lesions in high-fat diet (HFD)-fed rats subjected to a two-stage hepatocarcinogenesis model. Rats were fed with control basal diet or HFD, which was administered with SR alone or in combination with an antioxidant AGIQ in drinking water. An HFD increased body weight, intra-abdominal fat (adipose) tissue weight, and plasma lipids, which were reduced by coadministration of SR and AGIQ. SR and AGIQ coadministration also reduced hepatic steatosis and preneoplastic glutathione S-transferase placental form-positive foci, in association with decrease in NADPH oxidase (NOX) subunit p22phox-positive cells and an increase in active-caspase-3-positive cells in the foci. Hepatic gene expression analysis revealed that the coadministration of SR and AGIQ altered mRNA levels of lipogenic enzymes ( Scd1 and Fasn), antioxidant-related enzymes ( Catalase), NOX component ( P67phox), and anti-inflammatory transcriptional factor ( Pparg). Our results indicated that SR in combination with AGIQ had the potential of suppressing hyperlipidemia- and steatosis-related early hepatocarcinogenesis through the reduced expression of NOX subunits.

Unanticipated increases in hepatic steatosis among human immunodeficiency virus patients receiving mineralocorticoid receptor antagonist eplerenone for non-alcoholic fatty liver disease

BACKGROUND & AIMS

Non-alcoholic fatty liver disease is common in human immunodeficiency virus, but there are no approved therapies. The aim of this open-label proof-of-concept study was to determine the effect of the mineralocorticoid receptor antagonist eplerenone on hepatic fat in human immunodeficiency virus-infected patients with hepatic fat ≥5% by magnetic resonance spectroscopy.

METHODS

Five subjects received eplerenone (25 mg daily × 1 week followed by 50 mg daily × 23 weeks). Laboratory tests were done at each visit, and the primary endpoint, change in hepatic fat content, was determined by MRI spectroscopy at baseline and week 24.

RESULTS

The study was stopped early after observing unexpected significant increases in hepatic fat at week 24 (mean increase 13.0 ± 7.3%, P = .02). The increases in steatosis were accompanied by a tendency for transaminase values to decrease (alanine aminotransferase mean change -14 ± 16 IU/L, P = .14). There were no consistent changes in other metabolic parameters or blood pressure. Repeat assessment of hepatic steatosis 1-2 months after stopping study medication revealed improvements in steatosis towards baseline values.

CONCLUSIONS

The unexpected observation of increased hepatic steatosis with the administration of eplerenone led to early termination of the investigation. While limited because of the small number of participants and the open-label design, this study provides data to suggest that mineralocorticoid receptor antagonism with eplerenone may not be an effective approach to treat hepatic steatosis in human immunodeficiency virus or the general population. Additional research is needed to determine the pathophysiological mechanism behind these unanticipated observations.

Effects of combined low-dose spironolactone plus vitamin E vs vitamin E monotherapy on insulin resistance, non-invasive indices of steatosis and fibrosis, and adipokine levels in non-alcoholic fatty liver disease: a randomized controlled trial

The beneficial effects of mineralocorticoid receptor blockade by spironolactone have been shown in animal models of non-alcoholic fatty liver disease (NAFLD). The aim of the present 52-week randomized controlled trial was to compare the effects of low-dose spironolactone and vitamin E combination with those of vitamin E monotherapy on insulin resistance, non-invasive indices of hepatic steatosis and fibrosis, liver function tests, circulating adipokines and hormones in patients with histologically confirmed NAFLD. Homeostasis model of assessment of insulin resistance (HOMA-IR) and non-invasive indices of steatosis and fibrosis were calculated. Analysis was intention-to-treat. NAFLD liver fat score, an index of steatosis, decreased significantly in the combination treatment group (P = .028), but not in the vitamin E group, and the difference for group*time interaction was significant (P = .047). Alanine aminotransferase-to-platelet ratio index, an index of fibrosis, did not change. Insulin levels and HOMA-IR decreased significantly only within the combination group (P = .011 and P = .011, respectively). In conclusion, the combined low-dose spironolactone plus vitamin E regimen significantly decreased NAFLD liver fat score. Larger-scale trials are needed to clarify the effect of low-dose spironolactone on hepatic histology.

Eplerenone prevented obesity-induced inflammasome activation and glucose intolerance

Obesity-associated activation of the renin-angiotensin-aldosterone system is implicated in the pathogenesis of insulin resistance; however, influences of mineralocorticoid receptor (MR) inhibition remain unclear. Therefore, we aimed to clarify the anti-inflammatory mechanisms of MR inhibition using eplerenone, a selective MR antagonist, in C57BL/6 mice fed a high-fat diet (HFD) for 12 weeks. Eplerenone prevented excessive body weight gain and fat accumulation, ameliorated glucose intolerance and insulin resistance and enhanced energy metabolism. In the epididymal white adipose tissue (eWAT), eplerenone prevented obesity-induced accumulation of F4/80⁺CD11c⁺CD206^--M1-adipose tissue macrophage (ATM) and reduction of F4/80⁺CD11c^-CD206⁺-M2-ATM. Interestingly, M1-macrophage exhibited lower expression levels of MR, compared with M2-macrophage, in the ATM of eWAT and in vitro-polarized bone marrow-derived macrophages (BMDM). Importantly, eplerenone and MR knockdown attenuated the increase in the expression levels of proIl1b, Il6 and Tnfa, in the eWAT and liver of HFD-fed mice and LPS-stimulated BMDM. Moreover, eplerenone suppressed IL1b secretion from eWAT of HFD-fed mice. To reveal the anti-inflammatory mechanism, we investigated the involvement of NLRP3-inflammasome activation, a key process of IL1b overproduction. Eplerenone suppressed the expression of the inflammasome components, Nlrp3 and Caspase1, in the eWAT and liver. Concerning the second triggering factors, ROS production and ATP- and nigericin-induced IL1b secretion were suppressed by eplerenone in the LPS-primed BMDM. These results indicate that eplerenone inhibited both the priming and triggering signals that promote NLRP3-inflammasome activation. Therefore, we consider MR to be a crucial target to prevent metabolic disorders by suppressing inflammasome-mediated chronic inflammation in the adipose tissue and liver under obese conditions.

Developmental and extrahepatic physiological functions of SREBP pathway genes in mice

Sterol regulatory element-binding proteins (SREBPs), master transcriptional regulators of cholesterol and fatty acid synthesis, have been found to contribute to a diverse array of cellular processes. In this review, we focus on genetically engineered mice in which the activities of six components of the SREBP gene pathway, namely SREBP-1, SREBP-2, Scap, Insig-1, Insig-2, or Site-1 protease have been altered through gene knockout or transgenic approaches. In addition to the expected impacts on lipid metabolism, manipulation of these genes in mice is found to affect a wide array of developmental and physiologic processes ranging from interferon signaling in macrophages to synaptic transmission in the brain. The findings reviewed herein provide a blueprint to guide future studies defining the complex interactions between lipid biology and the physiologic processes of many distinct organ systems.

PDGFRβ Regulates Adipose Tissue Expansion and Glucose Metabolism via Vascular Remodeling in Diet-Induced Obesity

Platelet-derived growth factor (PDGF) is a key factor in angiogenesis; however, its role in adult obesity remains unclear. In order to clarify its pathophysiological role, we investigated the significance of PDGF receptor β (PDGFRβ) in adipose tissue expansion and glucose metabolism. Mature vessels in the epididymal white adipose tissue (eWAT) were tightly wrapped with pericytes in normal mice. Pericyte desorption from vessels and the subsequent proliferation of endothelial cells were markedly increased in the eWAT of diet-induced obese mice. Analyses with flow cytometry and adipose tissue cultures indicated that PDGF-B caused the detachment of pericytes from vessels in a concentration-dependent manner. M1-macrophages were a major type of cells expressing PDGF-B in obese adipose tissue. In contrast, pericyte detachment was attenuated and vascularity within eWAT was reduced in tamoxifen-inducible conditional Pdgfrb-knockout mice with decreases in adipocyte size and chronic inflammation. Furthermore, Pdgfrb-knockout mice showed enhanced energy expenditure. Consequently, diet-induced obesity and the associated deterioration of glucose metabolism in wild-type mice were absent in Pdgfrb-knockout mice. Therefore, PDGF-B-PDGFRβ signaling plays a significant role in the development of adipose tissue neovascularization and appears to be a fundamental target for the prevention of obesity and type 2 diabetes.

The Combination of Blueberry Juice and Probiotics Ameliorate Non-Alcoholic Steatohepatitis (NASH) by Affecting SREBP-1c/PNPLA-3 Pathway via PPAR-α

Nonalcoholic steatohepatitis (NASH) is liver inflammation and a major threat to public health. Several pharmaceutical agents have been used for NASH therapy but their high-rate side effects limit the use. Blueberry juice and probiotics (BP) have anti-inflammation and antibacterial properties, and may be potential candidates for NASH therapy. To understand the molecular mechanism, Sprague Dawley rats were used to create NASH models and received different treatments. Liver tissues were examined using HE (hematoxylin and eosin) and ORO (Oil Red O) stain, and serum biochemical indices were measured. The levels of peroxisome proliferators-activated receptor (PPAR)-α, sterol regulatory element binding protein-1c (SREBP-1c), Patatin-like phospholipase domain-containing protein 3 (PNPLA-3), inflammatory cytokines and apoptosis biomarkers in liver tissues were measured by qRT-PCR and Western blot. HE and ORO analysis indicated that the hepatocytes were seriously damaged with more and larger lipid droplets in NASH models while BP reduced the number and size of lipid droplets (p < 0.05). Meanwhile, BP increased the levels of SOD (superoxide dismutase), GSH (reduced glutathione) and HDL-C (high-density lipoprotein cholesterol), and reduced the levels of AST (aspartate aminotransferase), ALT (alanine aminotransferase), TG (triglycerides), LDL-C (low-density lipoprotein cholesterol) and MDA (malondialdehyde) in NASH models (p < 0.05). BP increased the level of PPAR-α (Peroxisome proliferator-activated receptor α), and reduced the levels of SREBP-1c (sterol regulatory element binding protein-1c) and PNPLA-3 (Patatin-like phospholipase domain-containing protein 3) (p < 0.05). BP reduced hepatic inflammation and apoptosis by affecting IL-6 (interleukin 6), TNF-α (Tumor necrosis factor α), caspase-3 and Bcl-2 in NASH models. Furthermore, PPAR-α inhibitor increased the level of SREBP-1c and PNPLA-3. Therefore, BP prevents NASH progression by affecting SREBP-1c/PNPLA-3 pathway via PPAR-α.

Preventive and chronic mineralocorticoid receptor antagonism is highly beneficial in obese SHHF rats

BACKGROUND AND PURPOSE

Mineralocorticoid receptor (MR) activation contributes to heart failure (HF) progression. Its overactivity in obesity is thought to accelerate cardiac remodelling and HF development. Given that MR antagonists (MRA) are beneficial in chronic HF patients, we hypothesized that early MRA treatment may target obesity-related disorders and consequently delay the development of HF.

EXPERIMENTAL APPROACH

Twenty spontaneously hypertensive HF dyslipidaemic obese SHHF(cp/cp) rats and 18 non-dyslipidaemic lean SHHF(+/+) controls underwent regular monitoring for their metabolic and cardiovascular phenotypes with or without MRA treatment [eplerenone (eple), 100 mg∙kg(-1) ∙day(-1) ] from 1.5 to 12.5 months of age.

KEY RESULTS

Eleven months of eple treatment in obese rats (SHHF(cp/cp) eple) reduced the obesity-related metabolic disorders observed in untreated SHHF(cp/cp) rats by reducing weight gain, triglycerides and total cholesterol levels and by preserving adiponectinaemia. The MRA treatment predominantly preserved diastolic and systolic functions in obese rats by alleviating the eccentric cardiac hypertrophy observed in untreated SHHF(cp/cp) animals and preserving ejection fraction (70 ± 1 vs. 59 ± 1%). The MRA also improved survival independently of these pressure effects.

CONCLUSION AND IMPLICATIONS

Early chronic eple treatment resulted in a delay in cardiac remodelling and HF onset in both SHHF(+/+) and SHHF(cp/cp) rats, whereas SHHF(cp/cp) rats further benefited from the MRA treatment through a reduction in their obesity and dyslipidaemia. These findings suggest that preventive MRA therapy may provide greater benefits in obese patients with additional risk factors of developing cardiovascular complications.

Hepatic manifestations of women with polycystic ovary syndrome

Women with polycystic ovary syndrome (PCOS) have a higher prevalence of nonalcoholic fatty liver disease (NAFLD) and nonalcoholic steatohepatitis (NASH) than the general population. The link between NAFLD/NASH and PCOS is not just a coincidence. Indeed, both of these disorders comprise common risk factors, including central obesity, insulin resistance, chronic low-grade inflammation, and hyperandrogenemia. The characteristics of hyperandrogenemia in women with PCOS include elevated total and free testosterone levels and low sex hormone-binding globulin levels and are reported to be associated with NAFLD and elevated liver enzymes; however, not all elevated androgen levels in women with PCOS have the same adverse effects on the liver. With the exception of weight loss and encouraging exercise in obese women, few evidence-based effective treatments target NAFLD/NASH in women with PCOS. Selective antiandrogens and insulin sensitizers might be beneficial in treating NAFLD/NASH in women with PCOS, but further elucidation is needed.

Activation of Kupffer Cells Is Associated with a Specific Dysbiosis Induced by Fructose or High Fat Diet in Mice

The increase consumption of fructose in diet is associated with liver inflammation. As a specific fructan substrate, fructose may modify the gut microbiota which is involved in obesity-induced liver disease. Here, we aimed to assess whether fructose-induced liver damage was associated with a specific dysbiosis, especially in mice fed a high fat diet (HFD). To this end, four groups of mice were fed with normal and HFD added or not with fructose. Body weight and glucose sensitivity, liver inflammation, dysbiosis and the phenotype of Kupffer cells were determined after 16 weeks of diet. Food intake was increased in the two groups of mice fed with the HFD. Mice fed with HFD and fructose showed a higher infiltration of lymphocytes into the liver and a lower inflammatory profile of Kupffer cells than mice fed with the HFD without fructose. The dysbiosis associated with diets showed that fructose specifically prevented the decrease of Mouse intestinal bacteria in HFD fed mice and increased Erysipelotrichi in mice fed with fructose, independently of the amount of fat. In conclusion, fructose, used as a sweetener, induced a dysbiosis which is different in presence of fat in the diet. Consequently, the activation of Kupffer cells involved in mice model of HFD-induced liver inflammation was not observed in an HFD/fructose combined diet. These data highlight that the complexity of diet composition could highly impact the development of liver lesions during obesity. Specific dysbiosis associated with the diet could explain that the progressions of liver damage are different.

Protein phosphatase 4 (PP4) functions as a critical regulator in tumor necrosis factor (TNF)-α-induced hepatic insulin resistance

Protein phosphatase 4 (PP4) was shown to participate in multiple cellular processes, including DNA damage response, cell cycle and embryo development. Recent studies demonstrated a looming role of PP4 in glucose metabolism. However, whether PP4 is involved in hepatic insulin resistance remains poorly understood. The objective of this study was to estimate the role of PP4 in tumor necrosis factor (TNF)-α-induced hepatic insulin resistance. db/db mice and TNF-α-treated C57BL/6J mice were used as hepatic insulin resistance animal models. In vitro models were established in both HepG2 cells and primary hepatocytes by TNF-α treatment. We found that increased expression and activity of PP4 occurred in the livers of db/db mice and TNF-α-induced hepatic insulin resistance both in vitro and in vivo. Actually, PP4 silencing and suppression of PP4 activity ameliorated TNF-α-induced hepatic insulin resistance, whereas over-expression of PP4 caused insulin resistance. We then further investigated the prodiabetic mechanism of PP4 in TNF-α-induced insulin resistance. We found that PP4 formed a complex with IRS-1 to promote phosphorylation of IRS-1 on serine 307 via JNK activation and reduce the expression of IRS-1. Thus, PP4 is an important regulator in inflammatory related insulin resistance.

Teneligliptin improves metabolic abnormalities in a mouse model of postmenopausal obesity

A decrease in serum estrogen levels in menopause is closely associated with the development of visceral obesity and the onset of type 2 diabetes in women. In the present study, we demonstrated the therapeutic effects of the novel DPP4 inhibitor, teneligliptin, on the features of postmenopausal obesity in mice. In the control group, female C57BL/6 mice were sham-operated and maintained on a standard diet. In the postmenopausal obese group, ovariectomized (OVX) mice were maintained on a high-fat diet, and were referred to as OVX-HF. In the treated group, teneligliptin at 60 mg/kg per day was administrated to OVX-HF, and were referred to as Tene. After a 12-week food challenge, the metabolic phenotypes of these mice were analyzed. Body weight, fat accumulation, and glucose intolerance were greater in OVX-HF than in control, while these abnormalities were markedly improved without alterations in calorie intake in Tene. Teneligliptin effectively ameliorated the characteristics of metabolic abnormalities associated with postmenopausal obesity. Regarding chronic inflammation in visceral adipose tissue, the numbers of F4/80(+)CD11c(+)CD206(-) M1-macrophages in flow cytometry, crown-like structure formation in immunohistochemistry, and proinflammatory cytokine expression were significantly attenuated in Tene. Hepatic steatosis was also markedly improved. Furthermore, decreased energy consumption in the dark and light phases, reduced locomotor activity in the dark phase, and lowered core body temperature in OVX-HF were ameliorated in Tene. Since obesity and reduced energy metabolism are a common physiology of menopause, teneligliptin appears to be beneficial as a treatment for type 2 diabetes in postmenopausal obesity.

Beneficial effects of mineralocorticoid receptor blockade in experimental non-alcoholic steatohepatitis

BACKGROUND

Therapeutic options to treat Non-alcoholic steatohepatitis (NASH) are limited. Mineralocorticoid receptor (MR) activation could play a role in hepatic fibrogenesis and its modulation could be beneficial for NASH.

AIM

To investigate whether eplerenone, a specific MR antagonist, ameliorates liver damage in experimental NASH.

METHODS

C57bl6 mice were fed a choline-deficient and amino acid-defined (CDAA) diet for 22 weeks with or without eplerenone supplementation. Serum levels of aminotransferases and aldosterone were measured and hepatic steatosis, inflammation and fibrosis scored histologically. Hepatic triglyceride content (HTC) and hepatic mRNA levels of pro-inflammatory pro-fibrotic, oxidative stress-associated genes and of MR were also assessed.

RESULTS

CDAA diet effectively induced fibrotic NASH, and increased the hepatic expression of pro-inflammatory, pro-fibrotic and oxidative stress-associated genes. Hepatic MR mRNA levels significantly correlated with the expression of pro-inflammatory and pro-fibrotic genes and were significantly increased in hepatic stellate cells obtained from CDAA-fed animals. Eplerenone administration was associated to a reduction in histological steatosis and attenuation of liver fibrosis development, which was associated to a significant decrease in the expression of collagen-α1, collagen type III, alpha 1 and Matrix metalloproteinase-2.

CONCLUSION

The expression of MR correlates with inflammation and fibrosis development in experimental NASH. Specific MR blockade with eplerenone has hepatic anti-steatotic and anti-fibrotic effects. These data identify eplerenone as a potential novel therapy for NASH. Considering its safety and FDA-approved status, human studies are warranted.