CB1 receptor blockade ameliorates hepatic fat infiltration and inflammation and increases Nrf2-AMPK pathway in a rat model of severely uncontrolled diabetes

Effect of incorporating tributyrin and tricaproin in milk replacer on the hepatic metabolome of calves

This study investigated the effects of including a spray-dried fat concentrate containing tributyrin (TB) and tricaproin (TC) in milk replacer (MR) on the liver metabolome of dairy calves. Forty-five male dairy calves (46.1 ± 4.6 kg BW; 2.1 ± 0.63 d of age; mean ± SD) were blocked in order of arrival at the research facility. Within each block, calves were randomly assigned to 3 MR treatments (n = 15 per group): (1) an MR containing milk fat serving as biological reference for fat composition (MF), (2) a control MR (CON) containing a blend of vegetable fats, and (3) an MR (TRI) containing the same mixture of vegetable fats as CON, into which TB and TC were incorporated. All MR were isoenergetic with 36% lactose, 27% fat, and 24% protein on a DM basis. Calves were housed individually and received MR (13.5% solids) via nipple buckets twice daily at 0630 and 1730 h. Daily MR allowance was 6.0 L from d 1 to 5, 7.0 L/d from d 6 to 9, and 8.0 L/d from d 10 to 35. Calves had ad libitum access to water and chopped straw but no starter feed was fed. On d 35 after arrival, calves were euthanized and liver tissue samples were collected and analyzed using a targeted metabolomics approach. Liquid chromatography and flow injection with electrospray ionization triple quadrupole mass spectrometry using an MxP Quant 500 kit was used. Distinct metabolic profiles emerged, with principal component analysis indicating differences between calves fed MF and those on other treatments, collectively accounting for almost 50% of the total variation. Partial least squares discriminant analysis confirmed significant differences between the liver metabolomes of calves fed MF and other treatments. Volcano plot analysis showed that compared with calves fed CON, 51 metabolites were higher in calves fed MF, including 34 phosphatidylcholines, 8 sphingomyelins, 3 lysophosphatidylcholines, 1 ceramide, 3 hexosylceramides, eicosapentaenoic acid (EPA) and glycochenodeoxycholic acid (GUDCA), while 8 metabolites were lower, including 2 phosphatidylcholines, 1 sphingomyelin (SM C22:3), 1 diacylglycerol (DG 16:0_18:2), 1 lysophosphatidylcholine (lysoPC a C18:2), 2 nitrogen-containing compounds (putrescine and serine), and C5 acylcarnitine. In addition, when comparing calves fed MF to calves fed TRI, 51 metabolites were higher in calves fed MF, including 37 phosphatidylcholines, 8 sphingomyelins, 4 lysophosphatidylcholines, 3 ceramides, 3 hexosylceramides, EPA and GUDCA, while 7 metabolites were lower, including 2 phosphatidylcholines, 1 sphingomyelin (SM C22:3), 1 diacylglycerol (DG 16:0_18:2), 1 lysophosphatidylcholine (lysoPC a C18:2), putrescine and valerylcarnitine (C5). Importantly, no significant differences in metabolites were found between calves fed CON and TRI, suggesting that TB and TC in MR had no effect on the liver metabolome. These results demonstrate that differences in MR fat composition between milk fat (MF) and vegetable fats (CON and TRI) significantly modulate the liver metabolome of calves and underscore the importance of addressing fat composition in MR formulations to optimize metabolic outcomes.

New peripherally-restricted CB1 receptor antagonists, PMG-505-010 and -013 ameliorate obesity-associated NAFLD and fibrosis

The endocannabinoid system plays a crucial role in metabolic regulation, prompting the investigation of cannabinoid type 1 receptor (CB1R) antagonists for obesity and its complications like non-alcoholic fatty liver disease (NAFLD). Concerns over psychiatric side effects led to the development of peripheral CB1R antagonists that circumvent the blood-brain barrier (BBB). In this study, we synthesized PMG-505-010 and PMG-505-013 as peripherally restricted CB1 receptor antagonists by modifying rimonabant to minimize BBB penetration. Physicochemical analysis confirmed their reduced lipophilicity and increased polarity compared to rimonabant, indicating limited brain exposure. Molecular docking studies revealed similar binding modes to rimonabant at CB1R, characterized by robust hydrophobic interactions. Functionally, they acted as CB1R antagonists and inverse agonists, effectively reversing CP55,940-induced cAMP inhibition. In a murine model of obesity-related NAFLD, PMG-505-010 and -013 improved metabolic profiles, including fasting blood glucose levels and dyslipidemia. They also ameliorated hepatic injury, steatosis, and inflammation, evidenced by reduced liver enzymes, lipid peroxidation, hepatic lipid levels, and inflammatory cytokine levels. Notably, these compounds inhibited hepatic fibrosis by reducing extracellular matrix (ECM) deposition and altering fibrosis-related gene and protein expressions. In conclusion, PMG-505-010 and PMG-505-013 hold promise for treating obesity-related liver diseases, including NAFLD and fibrosis, through selective peripheral CB1R targeting, potentially avoiding CNS-related side effects seen with earlier CB1R antagonists.

The molecular signature of the peripheral cannabinoid receptor 1 antagonist AM6545 in adipose, liver and muscle tissue

The endocannabinoid system plays an important role in the regulation of metabolism, growth and regeneration of peripheral tissues, including liver, adipose and muscle tissue. Studies in cells, rodents and humans showed that cannabinoid receptor 1 (CB1) antagonist treatment is an effective strategy to improve features of metabolic health such as substrate metabolism, at least in models of metabolic dysregulation. However, acute signaling events that might induce these metabolic adaptations are not understood. It is not clear whether, and to which extent, a single treatment with a CB1 antagonist induces acute effects in peripheral, metabolic tissues. Therefore, the present study compared the phosphorylation status of signaling pathways and metabolic markers in liver, adipose and muscle tissue of mice treated with the peripherally restricted CB1 antagonist AM6545 and vehicle-treated mice. Protein kinase A phosphorylation was downregulated in white and brown adipose tissue, whereas the mitogen-activated protein kinase, phospho-extracellular signal-regulated kinase, was higher in liver, white adipose and muscle tissue of AM6545-treated mice. Additionally, Akt-mammalian target of rapamycin activation was higher in all tissues of AM6545-treated mice, whereas the phosphorylation status of metabolic markers remained unaffected. These data indicate that acute CB1 antagonism is effective to induce phosphorylation events of signaling cascades and metabolic markers in metabolic tissues of healthy, lean mice within a 90-min time window. The observed adaptations to AM6545 treatment do not fully align with earlier in vitro and in vivo findings, which could be ascribed to differences in cell type, exposure intensity (dose and time), health status and species.

Ezetimibe, Niemann-Pick C1 like 1 inhibitor, modulates hepatic phospholipid metabolism to alleviate fat accumulation

Background

Ezetimibe, which lowers cholesterol by blocking the intestinal cholesterol transporter Niemann-Pick C1 like 1, is reported to reduce hepatic steatosis in humans and animals. Here, we demonstrate the changes in hepatic metabolites and lipids and explain the underlying mechanism of ezetimibe in hepatic steatosis.

Methods

We fed Otsuka Long-Evans Tokushima Fatty (OLETF) rats a high-fat diet (60 kcal % fat) with or vehicle (control) or ezetimibe (10 mg kg-1) via stomach gavage for 12 weeks and performed comprehensive metabolomic and lipidomic profiling of liver tissue. We used rat liver tissues, HepG2 hepatoma cell lines, and siRNA to explore the underlying mechanism.

Results

In OLETF rats on a high-fat diet, ezetimibe showed improvements in metabolic parameters and reduction in hepatic fat accumulation. The comprehensive metabolomic and lipidomic profiling revealed significant changes in phospholipids, particularly phosphatidylcholines (PC), and alterations in the fatty acyl-chain composition in hepatic PCs. Further analyses involving gene expression and triglyceride assessments in rat liver tissues, HepG2 hepatoma cell lines, and siRNA experiments unveiled that ezetimibe's mechanism involves the upregulation of key phospholipid biosynthesis genes, CTP:phosphocholine cytidylyltransferase alpha and phosphatidylethanolamine N-methyl-transferase, and the phospholipid remodeling gene lysophosphatidylcholine acyltransferase 3.

Conclusion

This study demonstrate that ezetimibe improves metabolic parameters and reduces hepatic fat accumulation by influencing the composition and levels of phospholipids, specifically phosphatidylcholines, and by upregulating genes related to phospholipid biosynthesis and remodeling. These findings provide valuable insights into the molecular pathways through which ezetimibe mitigates hepatic fat accumulation, emphasizing the role of phospholipid metabolism.

Pathophysiological Features of Rat Models of Nonalcoholic Fatty Liver Disease/Nonalcoholic Steatohepatitis

Nonalcoholic fatty liver disease (NAFLD)/nonalcoholic steatohepatitis (NASH) is caused by various factors, including genetic and/or environmental factors, and has complicated pathophysiological features during the development of the disease. NAFLD/NASH is recognized as an unmet medical need, and NAFLD/NASH animal models are essential tools for developing new therapies, including potential drugs and biomarkers. In this review, we describe the pathological features of the NAFLD/NASH rat models, focusing on the histopathology of hepatic fibrosis. NAFLD/NASH rat models are divided into three categories: diet-induced, genetic, and combined models based on diet, chemicals, and genetics. Rat models of NASH with hepatic fibrosis are especially expected to contribute to the development of new therapies, such as drugs and biomarkers.

Regulation of Intestinal Flora and Immune Response by Cyanidin Exhibits Protective Effect against Type-2 Diabetes in Rat Model

In the current study the effects of metformin and cyanidin on the immune system and intestinal flora in rats with type-2 diabetes was investigated. The findings showed that metformin or cyanidin treatment considerably reduced the rise in body weight and glucose levels induced by type-2 diabetes. The type-2 diabetic rats' glucose tolerance was significantly increased by cyanidin administration comparable to that of metformin. Cyanidin administration resulted in a significant reduction in serum cholesterol and low-density lipoprotein (LDL) levels in rats with type-2 diabetes. Treatment with cyanidin significantly increased the ratio of high-density lipoprotein to low-density lipoprotein in type-2 diabetes rats. Cyanidin administration significantly raised the ratio of Firmicutes to Bacteroidetes in the fecal samples of type-2 diabetic rats compared to the model group. In comparison to the model group, it also significantly raised the levels of Lactobacillus intestinalis, Lactobacillus gasseri, and Lactobacillus reuteri in the type-2 diabetes rats. In type-2 diabetes rat fecal samples, the abundance of Christensenellaceae significantly increased while Enterobacteriaceae and Proteobacteria were found to decrease upon cyanidin administration. Furthermore, cyanidin administration to the rats with type-2 diabetes significantly improved the glucose homeostasis. In conclusion, the study demonstrates that cyanidin enhances glucose homeostasis in rats with type-2 diabetes, potentially through controlling intestinal flora. Thus, cyanidin may be looked into more as a possible therapeutic agent for type 2 diabetes.

Effects of the CB1 receptor antagonists AM6545 and AM4113 on metabolic syndrome-induced prostatic hyperplasia in rats

Metabolic syndrome (MetS) is a combination of metabolic disorders that can predispose individuals to benign prostatic hyperplasia (BPH). The inhibition of the cannabinoid 1 (CB1) receptor has been used to treat metabolic disorders in animal models. This study reports the use of a peripherally restricted CB1 antagonist (AM6545) and a neutral CB1 antagonist (AM4113) to improve MetS-related BPH in rats. Animals were divided into three control groups to receive either a normal rodent diet, AM6545, or AM4113. MetS was induced in the fourth, fifth, and sixth groups using a concentrated fructose solution and high-salt diet delivered as food pellets for eight weeks. The fifth and sixth groups were further given AM6545 or AM4113 for additional four weeks. Body and prostate weights were measured and prostate sections were stained with hematoxylin eosin. Cyclin D1, markers of oxidative stress and inflammation, and levels of the endocannabinoids were recorded. BPH in rats with MetS was confirmed through increased prostate weight and index, as well as histopathology. Treatment with either AM6545 or AM4113 significantly decreased prostate weight, improved prostate histology, and reduced cyclin D1 expression compared with the MetS group. Groups treated with CB1 antagonists experienced reduced lipid peroxidation, recovered glutathione depletion, restored catalase activity, and had lower inflammatory markers interleukin 6 (IL-6) and tumor necrosis factor alpha (TNF-α). MetS rats treated with either AM6545 or AM4113 showed reduced concentrations of anandamide (AEA) and 2-arachidonoylglycerol (2-AG) in the prostate compared with the MetS group. In conclusion, the CB1 antagonists AM6545 and AM4113 protect against MetS-induced BPH through their anti-proliferative, antioxidant, and anti-inflammatory effects.

Krill oil inhibited adipogenic differentiation by inducing the nuclear Nrf2 expression and the AMPK activity

The current study investigated the antiadipogenic mechanism of krill oil from the 3T3-L1 adipocytes. The krill oil adhered to the criteria as a food standard by showing 50.8% of the total phospholipid, 5.27% myristic acid, and 1.63% linoleic acid. The lipid accumulation that was measured in the 3T3-L1 cells using oil red O staining was reduced up to 54% by the krill oil. The krill oil treatment reduced the adipogenic transcription factors by downregulating the sterol regulatory element binding protein 1 (SREBP1) and acetyl-CoA carboxylase (ACC), phospho-ACC, and AMP-activated protein kinase (AMPK) phosphorylation. The current study confirmed that the krill oil inhibited adipogenesis by downregulating SREBP1 and ACC via the upregulation of the AMPK and nuclear factors E2-related factor 2 (Nrf2) signaling pathway in the 3T3-L1 adipocytes. These findings suggest that krill oil is a good source of phospholipid and phosphatidylcholine, which could be a potential natural antiobesity ingredient by inhibiting adipogenesis.

Expanding Research on Cannabis-Based Medicines for Liver Steatosis: A Low-Risk High-Reward Way Out of the Present Deadlock?

Obesity and nonalcoholic fatty liver disease (NAFLD) constitute global and growing epidemics that result in therapeutic dead ends. There is an urgent need for new and accessible treatments to improve and widen both preventive and curative approaches against NAFLD. The endocannabinoid system (ECS) is recognized as a complex signaling apparatus closely related to metabolic disorders and is a key target for treating NAFLD. Despite a lack of conclusive clinical trials, observational and pre-clinical studies highlight putative benefits of phytocannabinoids on liver steatosis through multiple pathways. Owing to both its safety profile and its diversity of active compounds acting primarily (although not exclusively) on the ECS-and its expanded version, the endocannabinoidome, the Cannabis plant should be considered a major prospect in the treatment of NAFLD. However, seizing this opportunity, and intensifying clinical research in this direction, will require overcoming both scientific and nonscientific barriers.

Disorders of cancer metabolism: The therapeutic potential of cannabinoids

Abnormal energy metabolism, as one of the important hallmarks of cancer, was induced by multiple carcinogenic factors and tumor-specific microenvironments. It comprises aerobic glycolysis, de novo lipid biosynthesis, and glutamine-dependent anaplerosis. Considering that metabolic reprogramming provides various nutrients for tumor survival and development, it has been considered a potential target for cancer therapy. Cannabinoids have been shown to exhibit a variety of anticancer activities by unclear mechanisms. This paper first reviews the recent progress of related signaling pathways (reactive oxygen species (ROS), AMP-activated protein kinase (AMPK), mitogen-activated protein kinases (MAPK), phosphoinositide 3-kinase (PI3K), hypoxia-inducible factor-1alpha (HIF-1α), and p53) mediating the reprogramming of cancer metabolism (including glucose metabolism, lipid metabolism, and amino acid metabolism). Then we comprehensively explore the latest discoveries and possible mechanisms of the anticancer effects of cannabinoids through the regulation of the above-mentioned related signaling pathways, to provide new targets and insights for cancer prevention and treatment.

Blockade of CB1 or Activation of CB2 Cannabinoid Receptors Is Differentially Efficacious in the Treatment of the Early Pathological Events in Streptozotocin-Induced Diabetic Rats

Oxidative stress, neurodegeneration, neuroinflammation, and vascular leakage are believed to play a key role in the early stage of diabetic retinopathy (ESDR). The aim of this study was to investigate the blockade of cannabinoid receptor 1 (CB1R) and activation of cannabinoid receptor 2 (CB2R) as putative therapeutics for the treatment of the early toxic events in DR. Diabetic rats [streptozotocin (STZ)-induced] were treated topically (20 μL, 10 mg/mL), once daily for fourteen days (early stage DR model), with SR141716 (CB1R antagonist), AM1710 (CB2R agonist), and the dual treatment SR141716/AM1710. Immunohistochemical-histological, ELISA, and Evans-Blue analyses were performed to assess the neuroprotective and vasculoprotective properties of the pharmacological treatments on diabetes-induced retinal toxicity. Activation of CB2R or blockade of CB1R, as well as the dual treatment, attenuated the nitrative stress induced by diabetes. Both single treatments protected neural elements (e.g., RGC axons) and reduced vascular leakage. AM1710 alone reversed all toxic insults. These findings provide new knowledge regarding the differential efficacies of the cannabinoids, when administered topically, in the treatment of ESDR. Cannabinoid neuroprotection of the diabetic retina in ESDR may prove therapeutic in delaying the development of the advanced stage of the disease.

The Endocannabinoid System and Physical Activity—A Robust Duo in the Novel Therapeutic Approach against Metabolic Disorders

Rapidly increasing worldwide prevalence of obesity and related pathologies encompassing coronary heart disease, hypertension, metabolic syndrome, or type 2 diabetes constitute serious threats to global health and are associated with a significantly elevated risk of premature death. Considering the enormous burden of these pathologies, novel therapeutic and preventive patterns are indispensable. Dysregulation of one of the most complex biological systems in the human body namely, the endocannabinoid system (ECS) may result in metabolic imbalance and development of insulin resistance, type 2 diabetes, or non-alcoholic fatty liver disease. Furthermore, many studies showed that physical exercises, depending on their type, intensity, and frequency, exert various alterations within the ECS. Emerging evidence suggests that targeting the ECS via physical activity may produce robust beneficial effects on the course of metabolic pathologies. However, the data showing a direct correlation between the ECS and physical activity in the aspect of metabolic health are very scarce. Therefore, the aim of this review was to provide the most up-to-date state of knowledge about the interplay between the ECS activity and physical exercises in the novel therapeutic and preventive approach toward metabolic pathologies. We believe that this paper, at least in part, will fulfill the existing gap in knowledge and encourage researchers to further explore this very complex yet interesting link between the ECS, its action in physical activity, and subsequent positive outcomes for metabolic health.

Potential Implications of Rimonabant on Age-Related Oxidative Stress and Inflammation

Over the last decades, growing interest has turned to preventive and therapeutic approaches for achieving successful aging. Oxidative stress and inflammation are fundamental features of cardiovascular diseases; therefore, potential targets of them can improve cardiac outcomes. Our study aimed to examine the involvement of the endocannabinoid system, especially the CB1 receptor blockade, on inflammatory and oxidant/antioxidant processes. Twenty-month-old female and male Wistar rats were divided into rimonabant-treated and aging control (untreated) groups. Rimonabant, a selective CB1 receptor antagonist, was administered at the dose of 1 mg/kg/day intraperitoneally for 2 weeks. Cardiac amounts of ROS, the antioxidant glutathione and superoxide dismutase (SOD), and the activity and concentration of the heme oxygenase (HO) enzyme were detected. Among inflammatory parameters, nuclear factor-kappa B (NF-κB), tumor necrosis factor-alpha (TNF-α), and myeloperoxidase (MPO) enzyme activity were measured. Two weeks of low dose rimonabant treatment significantly reduced the cardiac ROS via boosting of the antioxidant defense mechanisms as regards the HO system, and the SOD and glutathione content. Consistently, the age-related inflammatory response was alleviated. Rimonabant-treated animals showed significantly decreased NF-κB, TNF-α, and MPO levels. Our findings prove the beneficial involvement of CB1 receptor blocker rimonabant on inflammatory and oxidative damages to the aging heart.

Rho-Kinase as a Therapeutic Target for Nonalcoholic Fatty Liver Diseases

Nonalcoholic fatty liver disease (NAFLD) is a major public health problem and the most common form of chronic liver disease, affecting 25% of the global population. Although NAFLD is closely linked with obesity, insulin resistance, and type 2 diabetes mellitus, knowledge on its pathogenesis remains incomplete. Emerging data have underscored the importance of Rho-kinase (Rho-associated coiled-coil-containing kinase [ROCK]) action in the maintenance of normal hepatic lipid homeostasis. In particular, pharmacological blockade of ROCK in hepatocytes or hepatic stellate cells prevents the progression of liver diseases such as NAFLD and fibrosis. Moreover, mice lacking hepatic ROCK1 are protected against obesity-induced fatty liver diseases by suppressing hepatic de novo lipogenesis. Here we review the roles of ROCK as an indispensable regulator of obesity-induced fatty liver disease and highlight the key cellular pathway governing hepatic lipid accumulation, with focus on de novo lipogenesis and its impact on therapeutic potential. Consequently, a comprehensive understanding of the metabolic milieu linking to liver dysfunction triggered by ROCK activation may help identify new targets for treating fatty liver diseases such as NAFLD.

Peripheral CB1R as a modulator of metabolic inflammation

Obesity is associated with chronic inflammation in insulin-sensitive tissues, including liver and adipose tissue, and causes hormonal/metabolic complications, such as insulin resistance. There is growing evidence that peripheral cannabinoid-type 1 receptor (CB1R) is a crucial participant in obesity-induced pro-inflammatory responses in insulin-target tissues, and its selective targeting could be a novel therapeutic strategy to break the link between insulin resistance and metabolic inflammation. In this review, we introduce the role of peripheral CB1R in metabolic inflammation and as a mediator of hormonal/metabolic complications that underlie metabolic syndrome, including fatty liver, insulin resistance, and dyslipidemia. We also discuss the therapeutic potential of second- and third-generation peripherally restricted CB1R antagonists for treating obesity-induced metabolic inflammation without eliciting central CB1R-mediated neurobehavioral effects, predictive of neuropsychiatric side effects, in humans.

miR‑875‑5p regulates IR and inflammation via targeting TXNRD1 in gestational diabetes rats

Gestational diabetes mellitus (GDM) is a serious life‑threatening disease that affects the mother and fetus. However, the pathogenesis of GDM is still unclear. microRNAs (miRs) play vital roles in the regulation of various cell functions. The present study aimed to investigate the effects of miR‑875‑5p and thioredoxin reductase 1 cytoplasmic (TXNRD1) in GDM rats and analyze the associated underlying mechanism. A GDM rat model was induced using an intraperitoneal injection of streptozotocin. miR‑875‑5p knockdown plasmids or TXNRD1 knockdown plasmids were injected into the rats via the caudal vein. miR‑875‑5p and TXNRD1 expression in the serum were detected using reverse transcription‑quantitative PCR (RT‑qPCR) or western blot (WB) analyses. The fasting blood‑glucose (FBG), fasting serum insulin, triglyceride and high density lipoprotein levels were detected by specific commercial kits. The inflammatory response and the induction of oxidative stress were analyzed by assessing the expression of associated markers via WB, RT‑qPCR or commercial kits. The pancreatic and placental injuries were detected by hematoxylin and eosin staining. The results indicated that miR‑875‑5p expression levels were downregulated, whereas TXNRD1 levels were upregulated in GDM rats compared with normal pregnancy rats. miR‑875‑5p significantly regulated TXNRD1 expression in GDM rats. miR‑875‑5p silencing notably reduced FBG and insulin resistance, which was accompanied by reduced expression levels of blood lipid and pro‑inflammatory markers as well as reduced oxidative stress. However, the effects of miR‑875‑5p could be reversed by TXNRD1 silencing. Therefore, the present study indicated that miR‑875‑5p regulated IR and inflammation by targeting TXNRD1 in GDM rats. miR‑875‑5p and TXNRD1 may be considered as potential targets for treating GDM.

Cannabis use and reduced risk of elevated fatty liver index in HIV-HCV co-infected patients: a longitudinal analysis (ANRS CO13 HEPAVIH)

Background: Cannabis use and elevated fatty liver index (FLI≥ 60) (a biomarker of hepatic steatosis in the general population) have been identified as predictors of HCV-related and overall mortality, respectively, in HIV-HCV co-infected patients. However, the relationship between cannabis use and the risk of elevated FLI has never been explored.Methods: Using five-year follow-up data from 997 HIV-HCV co-infected patients (ANRS CO13 HEPAVIH cohort), we analyzed the relationship between cannabis use and FLI using mixed-effects multivariable logistic (outcome: elevated FLI yes/no) and linear (outcome: continuous FLI) regression models.Results: At the last follow-up visit, 27.4% of patients reported regular or daily cannabis use and 27.8% had elevated FLI. After multivariable adjustment, regular or daily cannabis use was associated with a 55% lower risk of elevated FLI (adjusted odds ratio [95% confidence interval]: 0.45 [0.22; 0.94]; p = 0.033) and lower FLI values (adjusted model coefficient: -4.24 [-6.57; -1.91], p < 0.0001).Conclusions: Cannabis use is associated with a reduced risk of elevated fatty liver index in HIV-HCV co-infected patients. Further research is needed to confirm whether and how cannabinoids may inhibit the development of hepatic steatosis or other metabolic disorders in high-risk populations.

Transplantation of brown adipose tissue up-regulates miR-99a to ameliorate liver metabolic disorders in diabetic mice by targeting NOX4

Nonalcoholic fatty liver disease (NAFLD), main cause of liver damage, is inextricably linked to diabetes. However, there is no specific means to improve the pathology of fatty liver in diabetic patients. Brown adipose tissue (BAT) is an important endocrine organ that secretes adipokines and microRNAs (miRNAs) involved in systemic metabolic regulation. To investigate the effects of BAT transplantation on liver lipid metabolism in diabetic mice, we transplanted BAT from male donor mice into diabetic mice induced by streptozotocin (STZ) combined with high-fat diet (HFD). At 10 weeks after transplantation, BAT transplantation significantly decreased the blood glucose and lipid, downregulated FAS, CD36, Scd1, ACCα, NOX2, NOX4, TGF-β1, FN and COL-1, up-regulated Nrf2, reversed the pathological changes of liver and increased the circulating miR-99a in diabetic mice. To verify whether circulating miR-99a improves oxidative stress by targeting inhibition of NOX4, we used 0.4mM palmitic acid (PA) to treat the LO2 cells. The expression of NOX4 protein was significantly decreased after transfection with miR-99a mimic, and increased after transfection with miR-99a inhibitor. Luciferase reporter assay confirmed that miR-99a could target NOX4 mRNA. These findings clarify the role of miR-99a and NOX4 in liver beneficial effect of BAT transplantation in diabetic mice.

Cannabinoids in Metabolic Syndrome and Cardiac Fibrosis

PURPOSE OF REVIEW

This article provides a concise overview of how cannabinoids and the endocannabinoid system (ECS) have significant implications for the prevention and treatment of metabolic syndrome (MetS) and for the treatment of cardiovascular disorders, including cardiac fibrosis.

RECENT FINDINGS

Over the past few years, the ECS has emerged as a pivotal component of the homeostatic mechanisms for the regulation of many bodily functions, including inflammation, digestion, and energy metabolism. Therefore, the pharmacological modulation of the ECS by cannabinoids represents a novel strategy for the management of many diseases. Specifically, increasing evidence from preclinical research studies has opened new avenues for the development of cannabinoid-based therapies for the management and potential treatment of MetS and cardiovascular diseases. Current information indicates that modulation of the ECS can help maintain overall health and well-being due to its homeostatic function. From a therapeutic perspective, cannabinoids and the ECS have also been shown to play a key role in modulating pathophysiological states such as inflammatory, neurodegenerative, gastrointestinal, metabolic, and cardiovascular diseases, as well as cancer and pain. Thus, targeting and modulating the ECS with cannabinoids or cannabinoid derivatives may represent a major disease-modifying medical advancement to achieve successful treatment for MetS and certain cardiovascular diseases.

Targeting the Endocannabinoid CB1 Receptor to Treat Body Weight Disorders: A Preclinical and Clinical Review of the Therapeutic Potential of Past and Present CB1 Drugs

Obesity rates are increasing worldwide and there is a need for novel therapeutic treatment options. The endocannabinoid system has been linked to homeostatic processes, including metabolism, food intake, and the regulation of body weight. Rimonabant, an inverse agonist for the cannabinoid CB1 receptor, was effective at producing weight loss in obese subjects. However, due to adverse psychiatric side effects, rimonabant was removed from the market. More recently, we reported an inverse relationship between cannabis use and BMI, which has now been duplicated by several groups. As those results may appear contradictory, we review here preclinical and clinical studies that have studied the impact on body weight of various cannabinoid CB1 drugs. Notably, we will review the impact of CB1 inverse agonists, agonists, partial agonists, and neutral antagonists. Those findings clearly point out the cannabinoid CB1 as a potential effective target for the treatment of obesity. Recent preclinical studies suggest that ligands targeting the CB1 may retain the therapeutic potential of rimonabant without the negative side effect profile. Such approaches should be tested in clinical trials for validation.

Sodium butyrate protects against high-fat diet-induced oxidative stress in rat liver by promoting expression of nuclear factor E2-related factor 2

Oxidative stress is closely related to metabolic disorders, which can lead to various diseases. Nuclear factor E2-related factor 2 (Nrf2) is a central regulator of oxidative stress. Sodium butyrate (NaB) has been shown to alleviate oxidative stress and insulin resistance, yet how Nrf2 is involved in the action of NaB remains unclear. In the present study, rats were rendered obese by feeding a high-fat diet for 9 weeks. NaB (300 mg/kg), which was gavaged every 2 d for 7 weeks, significantly alleviated high-fat diet-induced oxidative stress and insulin resistance. Additionally, the insulin signalling pathway in the liver was activated by NaB, associated with significant activation of Nrf2, superoxide dismutase and glutathione. Furthermore, hepatic up-regulation of Nrf2 in NaB-treated rats was associated with reduced protein content of histone deacetylase 1 and increased histone H3 acetyl K9 (H3K9Ac) modification on the Nrf2 promoter. The actions of NaB were completely abolished when Nrf2 was knocked down in vitro. Taken together, NaB acts as a histone deacetylase inhibitor to up-regulate Nrf2 expression with enhanced H3K9Ac modification on its promoter. NaB-induced Nrf2 activation stimulates transcription of downstream antioxidant enzymes, thus contributing to the amelioration of high-fat diet-induced oxidative stress and insulin resistance.

A Guide to Targeting the Endocannabinoid System in Drug Design

The endocannabinoid system (ECS) is one of the most crucial systems in the human organism, exhibiting multi-purpose regulatory character. It is engaged in a vast array of physiological processes, including nociception, mood regulation, cognitive functions, neurogenesis and neuroprotection, appetite, lipid metabolism, as well as cell growth and proliferation. Thus, ECS proteins, including cannabinoid receptors and their endogenous ligands’ synthesizing and degrading enzymes, are promising therapeutic targets. Their modulation has been employed in or extensively studied as a treatment of multiple diseases. However, due to a complex nature of ECS and its crosstalk with other biological systems, the development of novel drugs turned out to be a challenging task. In this review, we summarize potential therapeutic applications for ECS-targeting drugs, especially focusing on promising synthetic compounds and preclinical studies. We put emphasis on modulation of specific proteins of ECS in different pathophysiological areas. In addition, we stress possible difficulties and risks and highlight proposed solutions. By presenting this review, we point out information pivotal in the spotlight of ECS-targeting drug design, as well as provide an overview of the current state of knowledge on ECS-related pharmacodynamics and show possible directions for needed research.

Novel CB1 receptor antagonist BAR-1 modifies pancreatic islet function and clinical parameters in prediabetic and diabetic mice

BACKGROUDS

Cannabinoid receptor antagonists have been suggested as a novel treatment for obesity and diabetes. We have developed a synthetic cannabinoid receptor antagonist denominated BAR-1. As the function and integrity of a β-cell cellular structure are important keys for diabetes onset, we evaluated the effects of pharmacological administration of BAR-1 on prediabetic and diabetic rodents.

METHODS

CD-1 mice fed a hypercaloric diet or treated with streptozotocin were treated with 10 mg/kg BAR-1 for 2, 4 or 8 weeks. Body weight, oral glucose tolerance test, HbA1c, triglycerides and insulin in serum were measured. In isolated islets, we evaluated stimulated secretion and mRNA expression, and relative area of islets in fixed pancreases. Docking analysis of BAR-1 was complemented.

RESULTS

BAR-1 treatment slowed down weight gain in prediabetic mice. Fasting glucose-insulin relation also decreased in BAR-1-treated mice and glucose-stimulated insulin secretion was increased in isolated islets, without effects in oral test. Diabetic mice treated with BAR-1 showed a reduced glucose and a partial recovery of islet integrity. Gene expression of insulin and glucagon showed biphasic behaviour, increasing after 4 weeks of BAR-1 administration; however, after 8 weeks, mRNA abundance decreased significantly. Administration of BAR-1 also prevents changes in endocannabinoid element expression observed in prediabetic mice. No changes were detected in other parameters studied, including the histological structure. A preliminary in-silico study suggests a close interaction with CB1 receptor.

CONCLUSIONS

BAR-1 induces improvement of islet function, isolated from both prediabetic and diabetic mice. Effects of BAR-1 suggest a possible interaction with other cannabinoid receptors.

Obesity Affects the Microbiota-Gut-Brain Axis and the Regulation Thereof by Endocannabinoids and Related Mediators

The hypothalamus regulates energy homeostasis by integrating environmental and internal signals to produce behavioral responses to start or stop eating. Many satiation signals are mediated by microbiota-derived metabolites coming from the gastrointestinal tract and acting also in the brain through a complex bidirectional communication system, the microbiota–gut–brain axis. In recent years, the intestinal microbiota has emerged as a critical regulator of hypothalamic appetite-related neuronal networks. Obesogenic high-fat diets (HFDs) enhance endocannabinoid levels, both in the brain and peripheral tissues. HFDs change the gut microbiota composition by altering the Firmicutes:Bacteroidetes ratio and causing endotoxemia mainly by rising the levels of lipopolysaccharide (LPS), the most potent immunogenic component of Gram-negative bacteria. Endotoxemia induces the collapse of the gut and brain barriers, interleukin 1β (IL1β)- and tumor necrosis factor α (TNFα)-mediated neuroinflammatory responses and gliosis, which alter the appetite-regulatory circuits of the brain mediobasal hypothalamic area delimited by the median eminence. This review summarizes the emerging state-of-the-art evidence on the function of the “expanded endocannabinoid (eCB) system” or endocannabinoidome at the crossroads between intestinal microbiota, gut-brain communication and host metabolism; and highlights the critical role of this intersection in the onset of obesity.

Vitamin D Ameliorates Fat Accumulation with AMPK/SIRT1 Activity in C2C12 Skeletal Muscle Cells

Excessive fat accumulation has been considered as a major contributing factor for muscle mitochondrial dysfunction and its associated metabolic complications. The purpose of present study is to investigate a role of vitamin D in muscle fat accumulation and mitochondrial changes. In differentiated C2C12 muscle cells, palmitic acid (PA) was pretreated, followed by incubation with 1,25-dihyroxyvitamin D (1,25(OH)2D) for 24 h. PA led to a significant increment of triglyceride (TG) levels with increased lipid peroxidation and cellular damage, which were reversed by 1,25(OH)2D. The supplementation of 1,25(OH)2D significantly enhanced PA-decreased mtDNA levels as well as mRNA levels involved in mitochondrial biogenesis such as nuclear respiratory factor 1 (NRF1), peroxisome proliferative activated receptor gamma coactivator-1α (PGC-1α), and mitochondrial transcription factor A (Tfam) in C2C12 myotubes. Additionally, 1,25(OH)2D significantly increased ATP levels and gene expression related to mitochondrial function such as carnitine palmitoyltransferase 1 (CPT1), peroxisome proliferator-activated receptor α (PPARα), very long-chain acyl-CoA dehydrogenase (VLCAD), long-chain acyl-CoA dehydrogenase (LCAD), medium-chain acyl-CoA dehydrogenase (MCAD), uncoupling protein 2 (UCP2), and UCP3 and the vitamin D pathway including 25-dihydroxyvitamin D3 24-hydroxylase (CYP24) and 25-hydroxyvitamin D3 1-alpha-hydroxylase (CYP27) in PA-treated C2C12 myotubes. In addition to significant increment of sirtuin 1 (SIRT1) mRNA expression, increased activation of adenosine monophosphate-activated protein kinase (AMPK) and SIRT1 was found in 1,25(OH)2D-treated C2C12 muscle cells. Thus, we suggest that the observed protective effect of vitamin D on muscle fat accumulation and mitochondrial dysfunction in a positive manner via modulating AMPK/SIRT1 activation.

Rodent models of obesity

Obese or overweight people exceed one-third of the global population and obesity along with diabetes mellitus consist basic components of metabolic syndrome, both of which are known cardio-cerebrovascular risk factors with detrimental consequences. These data signify the pandemic character of obesity and the necessity for effective treatments. Substantial advances have been accomplished in preclinical research of obesity by using animal models, which mimic the human disease. In particular, rodent models have been widely used for many decades with success for the elucidation of the pathophysiology of obesity, since they share physiological and genetic components with humans and appear advantageous in their husbandry. The most representative rodents include the laboratory mouse and rat. Within this review, we attempted to consolidate the most widely used mice and rat models of obesity and highlight their strengths as well as weaknesses in a critical way. Our aim was to bridge the gap between laboratory facilities and patient's bed and help the researcher find the appropriate animal model for his/her obesity research. This tactful selection of the appropriate model of obesity may offer more translational derived results. In this regard, we included, the main diet induced models, the chemical/mechanical ones, as well as a selection of monogenic or polygenic models.