Differential outcomes of high-fat diet on age-related rescaling of cochlear frequency place coding

Auditory frequency coding is place-specific, which depends on the mechanical coupling of the basilar membrane-outer hair cell (OHC)-tectorial membrane network. Prestin-based OHC electromotility improves cochlear frequency selectivity and sensitivity. Cochlear amplification determines the frequency coding wherein discrete sound frequencies find a 'best' place along the cochlear length. Loss of OHC is the leading cause of age-related hearing loss (ARHL) and is the most common cause of sensorineural hearing loss and compromised speech perception. Lipid interaction with Prestin impacts OHC function. It has been established that high-fat diet (HFD) is associated with ARHL. To determine whether genetic background and metabolism preserve cochlear frequency place coding, we examined the effect of HFD in C57BL/6J (B6) and CBA/CaJ (CBA) on ARHL.We found a significant rescuing effect on ARHL in aged B6 HFD cohort. Prestin levels and cell sizes were better maintained in the experimental B6-HFD group. We also found that distortion product otoacoustic emission (DPOAE) group delay measurement was preserved, which suggested stable frequency place coding. In contrast, the response to HFD in the CBA cohort was modest with no appreciable benefit to hearing threshold. Notably, group delay was shortened with age along with the control. In addition, the frequency dependent OHC nonlinear capacitance gradient was most pronounced at young age but decreased with age. Cochlear RNA-seq analysis revealed differential TRPV1 expression and lipid homeostasis. Activation of TRPV1 and downregulation of arachidonic acid led to downregulation of inflammatory response in B6 HFD, which protects the cochlea from ARHL. The genetic background and metabolic state-derived changes in OHC morphology and function collectively contribute to a redefined cochlear frequency place coding and improved age-related pitch perception.

Impact of Oral Administration of Lactiplantibacillus plantarum Strain CNCM I-4459 on Obesity Induced by High-Fat Diet in Mice

Recent evidence suggests that some lactobacilli strains, particularly Lactiplantibacillus plantarum, have a beneficial effect on obesity-associated syndromes. Several studies have investigated probiotic challenges in models of high-fat diet (HFD)-induced obesity, specifically with respect to its impact on hepatic and/or adipocyte metabolism, gut inflammation and epithelial barrier integrity, and microbiota composition. However, only a few studies have combined these aspects to generate a global understanding of how probiotics exert their protective effects. Here, we used the probiotic strain L. plantarum CNCM I-4459 and explored its impact on a mouse model of HFD-induced obesity. Briefly, mice were administered 1 × 109 CFUs/day and fed HFD for 12 weeks. Treatment with this strain improved insulin sensitivity by lowering serum levels of fasting glucose and fructosamine. Administration of the probiotic also affected the transport and metabolism of glucose, resulting in the downregulation of the hepatic Glut-4 and G6pase genes. Additionally, L. plantarum CNCM I-4459 promoted a decreased concentration of LDL-c and modulated hepatic lipid metabolism (downregulation of Fasn, Plin, and Cpt1α genes). Probiotic treatment also restored HFD-disrupted intestinal microbial composition by increasing microbial diversity and lowering the ratio of Firmicutes to Bacteroidetes. In conclusion, this probiotic strain represents a potential approach for at least partial restoration of the glucose sensitivity and lipid disruption that is associated with obesity.

Reduction of lauric acid content in virgin coconut oil improved plasma lipid profile in high-fat diet-induced hypercholesterolemic mice

Virgin coconut oil (VCO) is claimed to have various health benefits, but favorable effects of its major component (∼50%), lauric acid, are controversial. Therefore, we aimed to reduce lauric acid content (∼30%) in VCO and evaluate its effect compared to VCO and medium-chain triglycerides (MCT), on food intake, bodyweight (BW), lipid profiles, and hepatic histology. Female C57BL/6 mice were treated with different diets for 3 months: control (normal diet), high-fat diet (HF), HF + VCO, HF + MCT, HF + low lauric acid VCO (LLA), and normal diet + LLA (C + LLA). LLA was prepared by enzymatic interesterification of VCO with methyl octanoate (methyl caprylate) and methyl decanoate (methyl caprate). Plasma and liver lipids, including total cholesterol (TC), high-density lipoprotein (HDL), and triglyceride, were measured by colorimetric assay, and hepatic fat accumulation was examined by oil-red-O staining. HF mice exhibited high plasma and liver TC and low-density lipoprotein (LDL). VCO or MCT treatment lowered liver TC and LDL, whereas LLA increased plasma HDL and markedly improved TC:HDL ratio. The HF-induced hepatic fat accumulation was attenuated by all treatments, of which VCO was the most effective. Control mice administered with LLA demonstrated lower liver TC and LDL, but higher plasma TC and HDL compared to controls. Lowest BW gain and food intake were found in mice treated with LLA. In conclusion, VCO, MCT, and LLA ameliorated hepatic histopathology caused by HF. VCO and MCT improved liver lipid profiles, whereas LLA has more beneficial effect on plasma lipids via a better TC:HDL ratio and showed promise for BW control.

Effects of Mealworm Fermentation Extract and Soy Protein Mix Ratio on Hepatic Glucose and Lipid Metabolism in Obese-Induced Mice

Previous studies found that mealworm fermentation extract (TMP) reduced alcoholic hepatic steatogenesis. This study examined how the ratio of TMP and soy protein (SP) mix affected glucose and lipid metabolism in obese mice given a high-fat diet (HFD). Mice were given HFD supplemented with 100% SP or the following three ratios of TMP and SP mix for 12 weeks: 20% (S4T1), 40% (S3T2), and 60% (S2T3) TMP. When compared to the SP group, the S2T3 group had considerably lower body weight gain and food consumption. When compared to the SP group, the S2T3 group had slightly lower blood insulin and leptin levels, as well as a lower homeostasis model assessment of insulin resistance score. The use of TMP instead of SP reduced the size of epididymal adipose tissue cells. An increase in the extent of substitution of SP with TMP inhibited the gene expression of hepatic fructolysis/gluconeogenesis (KHK, ALDOB, DLD, and FBP1), lipogenesis (FAS, SCD1, CD36, and DGAT2), and its transcriptional factors (PPARγ and ChREBP). Furthermore, the S2T3 group dramatically reduced the expression of hepatic genes implicated in endoplasmic reticulum stress (PDI) and antioxidant defense (SOD1). The 60% TMP mix, in particular, reduced the expression of hepatic glucose and lipid metabolismrelated genes in HFD-fed mice. The manufacturing of functional processed goods may be accomplished by combining SP and TMP in a 2:3 ratio.

Immature Persimmon (Diospyros kaki Thunb.) Ethanol Extract Ameliorates High-Fat Diet-Induced Obesity by Modulating Lipid Metabolism

In this study, immature persimmon (Diospyros kaki Thunb.) ethanol extract was administered to an obese animal model fed a high-fat diet to measure weight change, adipose tissue weight, serum lipid level, and expression level of adipose-related genes to evaluate its efficacy. Administration of D. kaki ethanol extract (DKE) (100 and 500 mg/kg/d) decreased the body weight gain, adipose tissue weight, and serum triglyceride levels in mice fed a high-fat diet. Furthermore, it improved the leptin and adiponectin levels in the blood as well as gene expression in the liver. It also inhibited the expression of sterol regulatory element-binding protein-1c, inhibiting the production of triglyceride biosynthetic enzyme fatty acid synthesis and acetyl-CoA carboxylase, and decreased the expressions of peroxisome proliferator-activated receptor γ and CCAAT/enhancer-binding proteins that induce adipocyte differentiation. Therefore, these data suggest that DKE exerts beneficial effects on high-fat diet-induced obesity by modulating lipid metabolism in mice fed a high-fat diet.

Anti-Obesity Effects of the Larval Powder of Steamed and Lyophilized Mature Silkworms in a Newly Designed Adult Mouse Model

Recently, "mature" silkworms (MS) of Bombix mori have been considered a potential nutraceutical, with a number of health benefits reported for steamed and lyophilized MS powder (SMSP). However, no obesity-related effects have been reported for SMSP. In the present study, anti-obesity effects of SMSP were investigated in adult mice in vivo, aged 12 weeks at the onset of SMSP treatment, fed a normal diet (ND) and a high-fat diet (HFD), respectively, for 12 weeks. SMSP significantly suppressed body weight gain, intra-abdominal adipose tissue, and food efficiency in both ND-fed and HFD-fed adult mice. In addition, SMSP significantly decreased food intake and liver weight in HFD-fed mice, indicating that SMSP suppressed appetite and simultaneously reduced the conversion of feed into body weight in HFD-fed mice. SMSP also significantly lowered the serum levels of glucose, triglyceride, total cholesterol, low-density lipoprotein cholesterol, asparagine transaminase, alanine transaminase, and alkaline phosphatase. However, SMSP had no significant effect on the weights of the kidney, spleen, or thymus or the serum levels of blood urea nitrogen and creatinine. Taken together, the above results suggest that SMSP has potent anti-obesity effects and is safe for long-term use as a potential therapeutic and/or nutraceutical in both obese patients and non-obese individuals.

Older-aged C57BL/6 mice fed a diet high in saturated fat and sucrose for ten months show decreased resilience to aging

The ability to respond to physical stress that disrupts normal physiological homeostasis at an older age embraces the concept of resilience to aging. A physical stressor could be used to induce physiological responses that are age-related, since resilience declines with increasing age. Increased fat and sugar intake is a nutritional stress with a high prevalence of obesity in older people. In order to determine the effect of this type of diet on resilience to aging, 18-month-old C57BL/6J male mice were fed a diet high in saturated fat (lard) and sucrose (HFS) for ten months. At the end of the 10-month study, mice fed the HFS diet showed increased cognitive impairment, decreased cardiac function, decreased strength and agility, and increased severity of renal pathology compared to mice fed a rodent chow diet low in saturated fat and sucrose (LFS). The degree of response aligned with decreased resilience to the long-term adverse effects of the diet with characteristics of accelerated aging. This observation suggests additional studies could be conducted to investigate the relationship between an accelerated decline in resilience to aging and enhanced resilience to aging under different dietary conditions.

High-Carbohydrate Diet Consumption Poses a More Severe Liver Cholesterol Deposition than a High-Fat and High-Calorie Diet in Mice

In the past few decades, many researchers believed that a high-fat and high-calorie diet is the most critical factor leading to metabolic diseases. However, increasing evidence shows a high-carbohydrate and low-fat diet may also be a significant risk factor. It needs a comprehensive evaluation to prove which viewpoint is more persuasive. We systematically compared the effects of high-fat and high-calorie diets and high-carbohydrate and low-fat ones on glycolipid metabolism in mice to evaluate and compare the effects of different dietary patterns on metabolic changes in mice. Sixty 8-week-old male C57BL/6 mice were divided into four groups after acclimatization and 15% (F-15), 25% (F-25), 35% (F-35), and 45% (F-45) of their dietary energy was derived from fat for 24 weeks. The body weight, body-fat percentage, fasting blood glucose, lipid content in the serum, and triglyceride content in the livers of mice showed a significantly positive correlation with dietary oil supplementation. Interestingly, the total cholesterol content in the livers of mice in the F-15 group was significantly higher than that in other groups (p < 0.05). Compared with the F-45 group, the mRNA expression of sterol synthesis and absorption-related genes (e.g., Asgr1, mTorc1, Ucp20, Srebp2, Hmgcr, and Ldlr), liver fibrosis-related genes (e.g., Col4a1 and Adamts1) and inflammation-related genes (e.g., Il-1β and Il-6) were significantly higher in the F-15 group. Compared with the F-45 group, the relative abundance of unclassified_f_Lachnospiraceae and Akkermansia was decreased in the F-15 group. While unclassified_f_Lachnospiraceae and Akkermansia are potentially beneficial bacteria, they have the ability to produce short-chain fatty acids and modulate cholesterol metabolism. In addition, the relative abundance of unclassified_f_Lachnospiraceae and Akkermansia was significantly positively correlated with fatty acid transporters expression and negatively correlated with that of cholesteryl acyltransferase 1 and cholesterol synthesis-related genes. In conclusion, our study delineated how a high-fat and high-calorie diet (fat supplied higher than or equal to 35%) induced obesity and hepatic lipid deposition in mice. Although the high-carbohydrate and low-fat diet did not cause weight gain in mice, it induced cholesterol deposition in the liver. The mechanism is mainly through the induction of endogenous synthesis of cholesterol in mice liver through the ASGR1-mTORC1-USP20-HMGCR signaling pathway. The appropriate oil and carbon water ratio (dietary energy supply from fat of 25%) showed the best gluco-lipid metabolic homeostasis in mice.

Dynamic Alterations to Hepatic MicroRNA-29a in Response to Long-Term High-Fat Diet and EtOH Feeding

MicroRNA-29a (miR-29a) is a well characterized fibro-inflammatory molecule and its aberrant expression is linked to a variety of pathological liver conditions. The long-term effects of a high-fat diet (HFD) in combination with different levels of EtOH consumption on miR-29a expression and liver pathobiology are unknown. Mice at 8 weeks of age were divided into five groups (calorie-matched diet plus water (CMD) as a control group, HFD plus water (HFD) as a liver disease group, HFD plus 2% EtOH (HFD + 2% E), HFD + 10% E, and HFD + 20% E as intervention groups) and fed for 4, 13, 26, or 39 weeks. At each time point, analyses were performed for liver weight/body weight (BW) ratio, AST/ALT ratio, as well as liver histology assessments, which included inflammation, estimated fat deposition, lipid area, and fibrosis. Hepatic miR-29a was measured and correlations with phenotypic traits were determined. Four-week feeding produced no differences between the groups on all collected phenotypic traits or miR-29a expression, while significant effects were observed after 13 weeks, with EtOH concentration-specific induction of miR-29a. A turning point for most of the collected traits was apparent at 26 weeks, and miR-29a was significantly down-regulated with increasing liver injury. Overall, miR-29a up-regulation was associated with a lower liver/BW ratio, fat deposition, inflammation, and fibrosis, suggesting a protective role of miR-29a against liver disease progression. A HFD plus increasing concentrations of EtOH produces progressive adverse effects on the liver, with no evidence of beneficial effects of low-dose EtOH consumption. Moreover, miR-29a up-regulation is associated with less severe liver injury.

Ameliorating Effects of Bifidobacterium longum subsp. infantis FB3-14 against High-Fat-Diet-Induced Obesity and Gut Microbiota Disorder

Obesity has emerged as one of the most prevalent chronic diseases worldwide. Our study was conducted to investigate the anti-obese potential of novel probiotic Bifidobacterium longum subsp. infantis FB3-14 (FB3-14) and the underlying molecular mechanisms in high-fat diet (HFD)-fed mice. The results demonstrated that an 8-week FB3-14 intervention significantly suppressed the HFD-induced body and fat weight gain and abnormal alterations of the serum lipid parameter, restoring the levels of cholesterol (4.29 mmol/L) and low-density lipoprotein cholesterol (3.42 mmol/L). FB3-14 treatment also attenuated adipocyte expansion, hepatic injury, and low-grade systemic inflammation and restored the expressions of lipid-metabolism-related genes, including Hsl, Leptin, and Adiponectin. Furthermore, FB3-14 was observed to reduce the Firmicutes/Bacteroidetes ratio in obese mice; increase the abundance of Akkermansia muciniphila, unclassified_Muribaculaceae, Lachnospiraceae_NK4A136_group, and Bifidobacterim; and upregulate G protein-coupled receptor41 associated with higher levels of butyric acid. These results indicate the protective effectiveness of FB3-14 in HFD-driven obesity and gut microbiota disorders, highlighting the promising potential of FB3-14 as a functional nutrition supplement.

Alleviating Effects of Ovatodiolide and Antcin K Supplements on High-Fat Diet-Induced Cardiovascular Dysfunction in ApoE-Knockout Mice by Attenuating Oxidative Stress

A high-fat diet (HFD) is a major risk factor for cardiovascular diseases. Many pure compounds have been demonstrated to be effective in treating cardiovascular diseases. In this study, we investigated the alleviating effects of oral ovatodiolide and antcin K (OAK) supplements on HFD-induced cardiovascular dysfunction in apolipoprotein E (ApoE)-knockout mice. Cardiovascular dysfunction was induced in ApoE-knockout mice by feeding them an HFD for 12 weeks. The degree of cardiovascular dysfunction was assessed through echocardiography, hematological and biochemical analyses, and immunofluorescence and immunohistochemical staining. The HFD-fed mice exhibited cardiovascular dysfunction-abnormal blood biochemical index. The arterial wall tissue exhibited the marked deposition of lipids, upregulated expression of vascular cell adhesion molecule-1 and CD36 receptors, and downregulated expression of the ABCA1 receptor. Macrophages isolated from the peritoneal cavity of the mice exhibited increased levels of lipid accumulation, reactive oxygen species, and CD11b expression but reduced mitochondrial membrane potential. The expression of superoxide dismutase 2 was downregulated and that of tumor necrosis factor-α was upregulated in the myocardial tissue. Oral OAK supplements twice a day for 12 weeks significantly mitigated HFD-induced cardiovascular dysfunction in the experimental mice. Oral OAK supplements appear to be a promising strategy for treating HFD-induced cardiovascular dysfunction. The underlying mechanisms may involve the reduction of lipid accumulation in the artery and oxidative stress and inflammation in the cardiovascular tissue.

Effects of NKT Cells on Metabolic Disorders Caused by High-Fat Diet Using CD1d-Knockout Mice

Purpose

The purpose of this study was to investigate whether NKT cells play an important role in preventing or exacerbating diseases caused by high-fat diet (HFD) using CD1d-knockout (KO) mice which lack NKT cells.

Methods

Five-week-old male Balb/c (wild-type; WT) or CD1dKO mice were fed with control-diet (CTD) or HFD for 16 weeks.

Results

The present study revealed four main findings. First, CD1dKO mice were susceptible to obesity caused by HFD in comparison to WT mice. Second, clinical conditions of fatty liver caused by HFD were comparable between CD1dKO mice and WT mice. Third, HFD-fed WT mice showed high levels of serum biochemical markers, involved in lipid metabolisms, in comparison to WT mice fed a CTD. Notably, the serum concentrations of ALT, T-CHO, TG and HDL-C in CD1dKO mice fed a HFD were almost comparable to those of CD1dKO mice fed a CTD. Fourth, the expression of peroxisome proliferator-activated receptor (PPAR) γ, low-density lipoprotein receptor (LDLR), CD36 of epididymal adipose tissue enhanced and proprotein convertase subtilisin/kexin type (PCSK) 9 in serum decreased.

Conclusion

NKT cells were responsible for protection against HFD-induced obesity. However, CD1dKO mice were resistant to serum biochemical marker abnormalities after HFD feeding. One possible explanation is that the epididymal adipose tissue of CD1dKO mice could take up greater amounts of excess lipids in serum in comparison to WT mice.

Impact of Perinatal Coexposure to Chlorpyrifos and a High-Fat Diet on Kisspeptin and GnRHR Presence and Reproductive Organs

Emerging evidence has indicated the involvement of extrahypothalamic Kisspeptin and GnRHR in reproductive function. In this study, we evaluate if maternal exposure to the pesticide chlorpyrifos (CPF) and/or a high-fat diet (HFD) has an impact on the expression of Kisspeptin and GnRHR in the reproductive organs of rats' offspring. A total of 16 pregnant rats are divided into four groups: a control group (n = 4), CPF group (4 rats exposed daily to 1/mg/kg/day), HFD group (4 rats randomly fed a 5.25 kcal/g HFD), and coexposed group (4 rats exposed to CPF and HDF). At postnatal development postnatal day (PND) 60, male and female offspring were sacrificed. The reproductive organs (ovary and testis) were removed, and histological and immunohistological analysis and in silico quantification (TissueGnostics software 6.0.1.102, TissueFAXS, HistoQuest) were applied to investigate the impact of different treatments on Kisspeptin and GnRHR expression in reproductive organs. The main outcomes of the study showed a significant decrease in rat offspring's body weight in the CPF group from PND30 and PND60 (p < 0.05 and p < 0.01, respectively). Histological analysis showed a significant increase in the atretic follicle and abnormal testis structure with germ cell desquamation in the CPF-exposed group. The immunodetection quantification of protein shows a significant decrease in GnRHR and Kisspeptin in the HFD and CPF exposed groups, respectively, in testis rat offspring. Perinatal exposure to CPF and HFD exposure affect the reproduction function of rat offspring.

Metformin targets intestinal immune system signaling pathways in a high-fat diet-induced mouse model of obesity and insulin resistance

Introduction

Research findings of the past decade have highlighted the gut as the main site of action of the oral antihyperglycemic agent metformin despite its pharmacological role in the liver. Extensive evidence supports metformin's modulatory effect on the composition and function of gut microbiota, nevertheless, the underlying mechanisms of the host responses remain elusive. Our study aimed to evaluate metformin-induced alterations in the intestinal transcriptome profiles at different metabolic states.

Methods

The high-fat diet-induced mouse model of obesity and insulin resistance of both sexes was developed in a randomized block experiment and bulk RNA-Seq of the ileum tissue was the method of choice for comparative transcriptional profiling after metformin intervention for ten weeks.

Results

We found a prominent transcriptional effect of the diet itself with comparatively fewer genes responding to metformin intervention. The overrepresentation of immune-related genes was observed, including pronounced metformin-induced upregulation of immunoglobulin heavy-chain variable region coding Ighv1-7 gene in both high-fat diet and control diet-fed animals. Moreover, we provide evidence of the downregulation NF-kappa B signaling pathway in the small intestine of both obese and insulin-resistant animals as well as control animals after metformin treatment. Finally, our data pinpoint the gut microbiota as a crucial component in the metformin-mediated downregulation of NF-kappa B signaling evidenced by a positive correlation between the Rel and Rela gene expression levels and abundances of Parabacteroides distasonis, Bacteroides spp., and Lactobacillus spp. in the gut microbiota of the same animals.

Discussion

Our study supports the immunomodulatory effect of metformin in the ileum of obese and insulin-resistant C57BL/6N mice contributed by intestinal immunoglobulin responses, with a prominent emphasis on the downregulation of NF-kappa B signaling pathway, associated with alterations in the composition of the gut microbiome.

Progression to Obesity: Variations in Patterns of Metabolic Fluxes, Fat Accumulation, and Gastrointestinal Responses

Obesity is a multifactorial disorder that is remarkably heterogeneous. It presents itself in a variety of phenotypes that can be metabolically unhealthy or healthy, associate with no or multiple metabolic risk factors, gain extreme body weight (super-responders), as well as resist obesity despite the obesogenic environment (non-responders). Progression to obesity is ultimately linked to the overall net energy balance and activity of different metabolic fluxes. This is particularly evident from variations in fatty acids oxidation, metabolic fluxes through the pyruvate-phosphoenolpyruvate-oxaloacetate node, and extracellular accumulation of Krebs cycle metabolites, such as citrate. Patterns of fat accumulation with a focus on visceral and ectopic adipose tissue, microbiome composition, and the immune status of the gastrointestinal tract have emerged as the most promising targets that allow personalization of obesity and warrant further investigations into the critical issue of a wider and long-term weight control. Advances in understanding the biochemistry mechanisms underlying the heterogenous obesity phenotypes are critical to the development of targeted strategies to maintain healthy weight.

Promotion Effect of Coexposure to a High-Fat Diet and Nano-Diethylnitrosamine on the Progression of Fatty Liver Malignant Transformation into Liver Cancer

Overconsumption of high-fat foods increases the risk of fatty liver disease (FLD) and liver cancer with long pathogenic cycles. It is also known that the intake of the chemical poison nitrosamine and its nanopreparations can promote the development of liver injuries, such as FLD, and hepatic fibrosis, and significantly shorten the formation time of the liver cancer cycle. The present work confirmed that the coexposure of a high-fat diet (HFD) and nano-diethylnitrosamine (nano-DEN) altered the tumor microenvironment and studied the effect of this coexposure on the progression of fatty liver malignant transformation into liver cancer. Gene transcriptomics and immunostaining were used to evaluate the tumor promotion effect of the coexposure in mice. After coexposure treatment, tumor nodules were obviously increased, and inflammation levels were elevated. The liver transcriptomics analysis showed that the expression levels of inflammatory, fatty, and fibrosis-related factors in the coexposed group were increased in comparison with the nano-DEN- and high-fat-alone groups. The Kyoto Encyclopedia of Genes and Genomes (KEGG) results showed that coexposure aggravated the high expression of genes related to the carcinomatous pathway and accelerated the formation of the tumor microenvironment. The immunohistochemical staining results showed that the coexposure significantly increased the abnormal changes in proteins related to inflammation, proliferation, aging, and hypoxia in mouse liver tissues. The coexposure of high fat and nano-DEN aggravated the process of steatosis and carcinogenesis. In conclusion, the habitual consumption of pickled foods containing nitrosamines in a daily HFD significantly increases the risk of liver pathology lesions progressing from FLD to liver cancer.

Insoluble Dietary Fiber from Okara Combined with Intermittent Fasting Treatment Synergistically Confers Antiobesity Effects by Regulating Gut Microbiota and Its Metabolites

Insoluble dietary fiber (IDF) was recently revealed to have an antiobesity impact. However, the impact and potential mechanism of high-purity IDF derived from okara (HPSIDF) on obesity caused by a high-fat diet (HFD) remain unclear. Except for dietary supplementation, intermittent fasting (IF) has attracted extensive interest as a new dietary strategy against obesity. Thus, we hypothesize that HPSIDF combined with IF treatment may be more effective in preventing obesity. In this study, HPSIDF combined with IF treatment synergistically alleviated HFD-induced dyslipidemia, impaired glucose homeostasis, systemic inflammation, and fat accumulation. Furthermore, gut microbiota dysbiosis and lowered short-chain fatty acid synthesis were recovered by HPSIDF combined with IF treatment. Meanwhile, metabolomic analysis of feces revealed that HPSIDF combined with IF treatment obviously reversed the alterations of metabolic pathways and differential metabolites induced by HFD, which were linked to the modulations of the gut microbiota. Collectively, our findings indicated that HPSIDF combined with IF treatment has great potential to substantially enhance antiobesity efficacy by modulating the gut microbiota and its metabolites.

The Effects of Dietary Chromium Supplementation along with Discontinuing a High-Fat Diet on the Microbial Enzymatic Activity and the Production of SCFAs in the Faeces of Rats

The present study assessed the changes in faecal microbial activity in obese Wistar rats fed high-fat or low-fat diets supplemented with various forms of chromium (picolinate or nanoparticles). The 18-week study was divided into two phases: an introductory period (9 weeks; obesity status induction via a high-fat diet) and an experimental period (9 weeks; maintained on a high-fat diet or switched to a low-fat diet and Cr supplementation). During the experimental period (10-18 weeks of feeding), samples of fresh faeces were collected on chosen days. The bacterial enzymatic activity and short-chain fatty acids (SCFAs) concentration were assessed to characterise the dynamism of the changes in faecal microbial metabolic activity under the applied dietary treatments. The results indicated that faecal microbial metabolic activity displayed several adaptation mechanisms in response to modifications in dietary conditions, and a beneficial outcome resulted from a pro-healthy dietary habit change, that is, switching from a high-fat to a low-fat diet. Dietary supplementation with chromium nanoparticles further modulated the aforementioned microbial activity, i.e., diminished the extracellular and total enzymatic activities, while the effect of chromium picolinate addition was negligible. Both the high-fat diet and the addition of chromium nanoparticles reduced SCFA concentrations and increased the faecal pH values.

High-Intensity Interval Training Ameliorates High-Fat Diet-Induced Metabolic Disorders via the Cyclic GMP-AMP Synthase-Stimulator of Interferon Gene Signaling Pathway

Metabolic diseases are growing in prevalence worldwide. Although the pathogenesis of metabolic diseases remains ambiguous, the correlation between cyclic GMP-AMP synthase (cGAS)-stimulator of interferon gene (STING) and metabolic diseases has been identified recently. Exercise is an effective intervention protecting against metabolic diseases, however, the role of the cGAS-STING signaling pathway in this process is unclear, and the effect and mechanism of different exercise intensities on metabolic disorders are still unknown. Thus, we explored the association between exercise to ameliorate HFD-induced metabolic disorders and the cGAS-STING signaling pathway and compared the effects of high-intensity interval training (HIIT) and moderate-intensity continuous training (MICT). Male C57BL/6 mice (6-8 weeks old) were fed HFD for 8 weeks to establish a metabolic disease model and were subjected to 8-week MICT or HIIT training. Glucose tolerance tests (GTT) and insulin tolerance tests (ITT) were used to assess glucose metabolism. Serum triglyceride (TG) and total cholesterol (TC) were measured to evaluate lipid metabolism. Oil red staining was used to observe the lipid droplets in the gastrocnemius muscle. An enzyme-linked immunosorbent assay was used to detect the serum inflammatory factors IL-6 and IFN-β. The protein expression of the cGAS-STING signaling pathway was detected by the WesTM automatic protein expression analysis system. We reported that HFD induced metabolic disorders with obesity, abnormal glucolipid metabolism, and significant inflammatory responses. Both HIIT and MICT ameliorated the above adverse reactions, but MICT was superior to HIIT in improving glucolipid disorders. Additionally, HIIT significantly increased the expression of STING protein, as well as the phosphorylation of TBKI and the ratio of p-IRF3/IRF3. MICT only increased the expression of STING protein. Our findings suggest that HIIT may alleviate HFD-induced metabolic disorder phenotype through the cGAS-STING signaling pathway. However, the improvement of MICT on metabolic disorder phenotype is less associated with the cGAS-STING pathway, which needs to be further explored.

Adipose Tissue Protects against Hepatic Steatosis in Male Rats Fed a High-Fat Diet plus Liquid Fructose: Sex-Related Differences

Non-alcoholic fatty liver disease is a sexual dimorphic disease, with adipose tissue playing an essential role. Our previous work showed that female rats fed a high-fat high-fructose diet devoid of cholesterol (HFHFr) developed simple hepatic steatosis dissociated from obesity. This study assessed the impact of the HFHFr diet on the male rat metabolism compared with data obtained for female rats. A total of 16 Sprague Dawley (SD) male rats were fed either a control (standard rodent chow and water) or HFHFr (high-fat diet devoid of cholesterol, plus 10% fructose in drinking water) diet for 3 months. Unlike female rats, and despite similar increases in energy consumption, HFHFr males showed increased adiposity and hyperleptinemia. The expression of hormone-sensitive lipase in the subcutaneous white adipose tissue was enhanced, leading to high free fatty acid and glycerol serum levels. HFHFr males presented hypertriglyceridemia, but not hepatic steatosis, partially due to enhanced liver PPARα-related fatty acid β-oxidation and the VLDL-promoting effect of leptin. In conclusion, the SD rats showed a sex-related dimorphic response to the HFHFr diet. Contrary to previous results for HFHFr female rats, the male rats were able to expand the adipose tissue, increase fatty acid catabolism, or export it as VLDL, avoiding liver lipid deposition.

CAR Protects Females from Diet-Induced Steatosis and Associated Metabolic Disorders

Non-Alcoholic Fatty Liver Disease (NAFLD) is the most common cause of chronic liver disease worldwide, affecting 70-90% of obese individuals. In humans, a lower NAFLD incidence is reported in pre-menopausal women, although the mechanisms affording this protection remain under-investigated. Here, we tested the hypothesis that the constitutive androstane nuclear receptor (CAR) plays a role in the pathogenesis of experimental NAFLD. Male and female wild-type (WT) and CAR knock-out (CAR-/-) mice were subjected to a high-fat diet (HFD) for 16 weeks. We examined the metabolic phenotype of mice through body weight follow-up, glucose tolerance tests, analysis of plasmatic metabolic markers, hepatic lipid accumulation, and hepatic transcriptome. Finally, we examined the potential impact of HFD and CAR deletion on specific brain regions, focusing on glial cells. HFD-induced weight gain and hepatic steatosis are more pronounced in WT males than females. CAR-/- females present a NASH-like hepatic transcriptomic signature suggesting a potential NAFLD to NASH transition. Transcriptomic correlation analysis highlighted a possible cross-talk between CAR and ERα receptors. The peripheral effects of CAR deletion in female mice were associated with astrogliosis in the hypothalamus. These findings prove that nuclear receptor CAR may be a potential mechanism entry-point and a therapeutic target for treating NAFLD/NASH.

Cheong-sang-bang-pung-san alleviated hepatic lipid accumulation by regulating lipid metabolism in vitro and in vivo

Introduction: The occurrence of fatty liver disease, resulting from the accumulation of excessive fat within the liver, has been showing a significant and rapid increase. This study aimed to evaluate the therapeutic effects of Cheong-sang-bang-pung-san extract (CB) on fatty liver disease, and to elucidate the underlying mechanisms. Methods: We used a high-fat diet (HFD)-fed fatty liver mice and free fatty acid (FFA) induced HepG2 cell lipid accumulation model. The levels of serum, hepatic, and intracellular lipid content were assessed. Histopathological staining was used to evaluate the extent of hepatic lipid accumulation. Real-time polymerase chain reaction and Western blotting were conducted to examine the expression of factors associated with lipid metabolism. Results: We demonstrated that treatment with CB dramatically reduced body weight, liver weight, and fat mass, and improved the serum and hepatic lipid profiles in HFD-induced fatty liver mice. Additionally, CB alleviated lipid accumulation in HFD-fed mice by controlling lipid metabolism, including fatty acid uptake, triglyceride and cholesterol synthesis, and fatty acid oxidation, at the mRNA as well as protein levels. In free fatty acid-treated HepG2 cells, CB significantly reduced intracellular lipid accumulation by regulating lipid metabolism via the activation of AMP-activated protein kinase. Conclusion: These findings provide insights into the mechanisms underlying CB's effects on liver steatosis and position of CB as a potential therapeutic candidate for managing lipid metabolic disorders.

Association of Short-Chain Fatty Acids with Gut Microbiota and Lipid Metabolism in Mice with Diarrhea Induced by High-Fat Diet in a Fatigued State

SCOPE

Preliminary research finds that a high-fat diet (HFD) in a fatigued state triggers diarrhea, but the exact mechanism has not been clarified. To address concerns about the pathogenesis of diarrhea, the study evaluates the composition and metabolomics of the gut microbiota.

METHODS AND RESULTS

The study uses the multiple platform apparatus device to induce fatigue in mice, combined with intragastric administration of lard-caused diarrhea. Subsequently, the characteristics and interaction relationship of gut microbiota, short-chain fatty acids (SCFAs), inflammatory biomarkers, brain-gut peptides, and lipid metabolism are analyzed at the end of the experiment. HFD in a fatigued state results in a significant increase in interleukin-17, interleukin-6, cholecystokinin, somatostatin, and malondialdehyde content in mice (p < 0.05), along with a substantial decrease in high-density lipoprotein (p < 0.05). Additionally, an HFD in a fatigued state causes changes in the structure and composition of the gut microbiota, with Lactobacillus murinus as its characteristic bacteria, and reduces the production of SCFAs.

CONCLUSIONS

An HFD in a fatigued state triggers diarrhea, possibly associated with gut content microbiota dysbiosis, SCFAs deprivation, increased inflammation, and dysregulated lipid metabolism.

High-fat diet aggravates the severity of the in vitro posttraumatic osteoarthritis model through macrophagic FBW7

Osteoarthritis (OA) is a prevalent and distressing chronic degenerative joint disorder characterized by damaged articular cartilage and inflamed joints. Among risk factors, obesity has emerged as the second-leading contributor to OA after age. Obesity is believed to play a key role in the development and progression of OA. This study aimed to investigate the role and underlying mechanisms of high-fat diet (HFD)-induced obesity in the development of OA. Our findings revealed that HFD could aggravate the destabilization of the medial meniscus (DMM)-induced damage in the mouse model of obesity. Similar results were observed when macrophages obtained from HFD-fed mice were cocultured with cartilage and subsequently stimulated with interleukin-1β (IL-1β). Mechanistically, we observed a decrease in the expression of intraarticular macrophagic FBW7, which was implicated in the aggravation of OA in the HFD-fed animal. Furthermore, by modulating the immune status of macrophages, we found that reversing the macrophagic expression of FBW7 in these cells can alleviate the chondrocyte damage. In conclusion, this study provides novel insights into the pathological mechanisms underlying HFD-related OA development by identifying the role of FBW7 in synovial macrophages. These findings open up new avenues for research and therapeutic interventions targeting HFD-related OA.

High-fat diet reveals the impact of Sar1b defects on lipid and lipoprotein profile and cholesterol metabolism

Biallelic pathogenic variants of the Sar1b gene cause chylomicron retention disease (CRD) whose central phenotype is the inability to secrete chylomicrons. Patients with CRD experience numerous clinical symptoms such as gastrointestinal, hepatic, neuromuscular, ophthalmic, and cardiological abnormalities. Recently, the production of mice expressing either a targeted deletion or mutation of Sar1b recapitulated biochemical and gastrointestinal defects associated with CRD. The present study was conducted to better understand little-known aspects of Sar1b mutations, including mouse embryonic development, lipid profile, and lipoprotein composition in response to high-fat diet, gut and liver cholesterol metabolism, sex-specific effects, and genotype-phenotype differences. Sar1b deletion and mutation produce a lethal phenotype in homozygous mice, which display intestinal lipid accumulation without any gross morphological abnormalities. On high-fat diet, mutant mice exhibit more marked abnormalities in body composition, adipose tissue and liver weight, plasma cholesterol, non-HDL cholesterol and polyunsaturated fatty acids than those on the regular Chow diet. Divergences were also noted in lipoprotein lipid composition, lipid ratios (serving as indices of particle size) and lipoprotein-apolipoprotein distribution. Sar1b defects significantly reduce gut cholesterol accumulation while altering key players in cholesterol metabolism. Noteworthy, variations were observed between males and females, and between Sar1b deletion and mutation phenotypes. Overall, mutant animal findings reveal the importance of Sar1b in several biochemical, metabolic and developmental processes.

Extracts of Dunkelfelder Grape Seeds and Peel Increase the Metabolic Rate and Reduce Fat Deposition in Mice Maintained on a High-Fat Diet

Chronic high-fat diet intake may induce obesity and increase the risk of metabolic syndrome. The pomace of grape (Vitis vinifera L.) is rich in polyphenols, which are candidates for anti-obesity therapy. The present study aimed to investigate the effects of Dunkelfelder grape seed extract (GSE) and grape peel extract (GPE) on lipid and energy metabolism disorders in mice maintained on a high-fat diet (HFD). Male nine-week C57BL/6J mice were randomly assigned to one of four groups, namely, the normal chow diet (ND), HFD, HFD plus GSE (400 mg/kg BW) administered by oral gavage, or HFD plus GPE (400 mg/kg BW) administered by oral gavage. There were eight mice per group, and the experiment was 14 weeks in duration. The results showed that GSE and GPE treatments did not affect energy intake in mice on a high-fat diet, but body weight gain was 24.5% and 17.3% lower in the GSE- and GPE-treated mice than in the HFD group, respectively. They also decreased blood triglyceride (TG), total cholesterol (TC), and fasting blood glucose levels and increased high-density lipoprotein cholesterol (HDL-C). In addition, GSE and GPE reduced adipose tissue weight and excessive lipid droplet accumulation in the adipocytes. The metabolic chamber test showed that the GSE and GPE treatments enhanced oxygen consumption, carbon dioxide production, and heat release while decreasing the respiratory exchange rate (RER). This suggests that GSE and GPE augmented fuel oxidation and energy generation and increased the proportion of lipids being utilized in energy metabolism. GSE and GPE also upregulated the genes controlling lipolysis and downregulated those controlling lipogenesis in adipose tissues. Moreover, they significantly increased the expression levels of the genes regulating thermogenesis in BAT, eWAT, and iWAT, and mitochondrial biogenesis in all three types of adipose tissue. In conclusion, the present study empirically demonstrated that GSE and GPE enhance body fat utilization by augmenting lipid and energy metabolism and could, therefore, ameliorate high-fat diet-induced obesity.

Paired microbiome and metabolome analyses associate bile acid changes with colorectal cancer progression

Colorectal cancer (CRC) is driven by genomic alterations in concert with dietary influences, with the gut microbiome implicated as an effector in disease development and progression. While meta-analyses have provided mechanistic insight into patients with CRC, study heterogeneity has limited causal associations. Using multi-omics studies on genetically controlled cohorts of mice, we identify diet as the major driver of microbial and metabolomic differences, with reductions in α diversity and widespread changes in cecal metabolites seen in high-fat diet (HFD)-fed mice. In addition, non-classic amino acid conjugation of the bile acid cholic acid (AA-CA) increased with HFD. We show that AA-CAs impact intestinal stem cell growth and demonstrate that Ileibacterium valens and Ruminococcus gnavus are able to synthesize these AA-CAs. This multi-omics dataset implicates diet-induced shifts in the microbiome and the metabolome in disease progression and has potential utility in future diagnostic and therapeutic developments.

Hibiscus sabdariffa Linn. Extract Increases the mRNA Expression of the Arcuate Nucleus Leptin Receptor and is Predicted in silico as an Anti-obesity Agent

BACKGROUND

Leptin is predominant in regulating body weight by stimulating energy expenditure through its neuronal action in the brain. Moreover, it is projected to adipose tissue and induces adipocyte browning by activating the β3-adrenergic receptor (β3AR). However, the expression of leptin receptor (Lep-R) and β3AR in people with obesity is downregulated.

AIM

We hypothesized that Hibiscus sabdariffa Linn. extract (HSE) would increase hypothalamus arcuate nucleus (ARC) Lep-R and white adipose tissue (WAT) β3AR mRNA expression in DIO rats. This study also analyzed the potency of H. sabdariffa bioactive compounds as activators of Lep-R and β3AR by an in-silico experiment.

METHODS

Twenty-four male Sprague-Dawley rats were divided into four groups: Control (standard food), DIO (high-fat diet), DIO-Hib200 (HFD+HSE 200 mg/kg BW), and DIO-Hib400 (HFD+HSE400 mg/kg BW). HSE was administered orally for five weeks, once a day.

RESULTS

HSE administration significantly (P<0,05) increased the ARC Lep-R expression. The Lee index significantly decreased to the normal range (≤ 310) with p<0,001 for DIO-Hib200 and p<0,01 for DIO-Hib400. Among 39 bioactive compounds, 5-O-caffeoyl shikimic acid exhibited high free binding scores (-8,63) for Lep-R, and myricetin_3_arabinogalactoside had high free binding scores (-9,39) for β3AR. These binding predictions could activate Lep-R and β3AR.

CONCLUSION

This study highlights that HSE could be a potential therapeutic target for obesity by increasing LepR mRNA and leptin sensitivity, enhancing energy expenditure, and reducing obesity.

Bergamot Polyphenolic Extract Combined with Albedo and Pulp Fibres Counteracts Changes in Gut Microbiota Associated with High-Fat Diet: Implications for Lipoprotein Size Re-Arrangement

Evidence exists that the gut microbiota contributes to the alterations of lipid metabolism associated with high-fat diet (HFD). Moreover, the gut microbiota has been found to modulate the metabolism and absorption of dietary lipids, thereby affecting the formation of lipoproteins occurring at the intestinal level as well as systemically, though the pathophysiological implication of altered microbiota composition in HFD and its role in the development of atherosclerotic vascular disease (ATVD) remain to be better clarified. Recently, evidence has been collected indicating that supplementation with natural polyphenols and fibres accounts for an improvement of HFD-associated intestinal dysbiosis, thereby leading to improved lipidaemic profile. This study aimed to investigate the protective effect of a bergamot polyphenolic extract (BPE) containing 48% polyphenols enriched with albedo and pulp-derived micronized fibres (BMF) in the gut microbiota of HFD-induced dyslipidaemia. In particular, rats that received an HFD over a period of four consecutive weeks showed a significant increase in plasma cholesterol, triglycerides and plasma glucose compared to a normal-fat diet (NFD) group. This effect was accompanied by body weight increase and alteration of lipoprotein size and concentration, followed by high levels of MDA, a biomarker of lipid peroxidation. Treatment with a combination of BPE plus BMF (50/50%) resulted in a significant reduction in alterations of the metabolic parameters found in HFD-fed rats, an effect associated with increased size of lipoproteins. Furthermore, the effect of BPE plus BMF treatment on metabolic balance and lipoprotein size re-arrangement was associated with reduced gut-derived lipopolysaccharide (LPS) levels, an effect subsequent to improved gut microbiota as expressed by modulation of the Gram-negative bacteria Proteobacteria, as well as Firmicutes and Bacteroidetes. This study suggests that nutraceutical supplementation of HFD-fed rats with BPE and BMP or with their combination product leads to restored gut microbiota, an effect associated with lipoprotein size re-arrangement and better lipidaemic and metabolic profiles.

Modulatory Effects of Co-Fermented Pu-erh Tea with Aqueous Corn Silk Extract on Gut Microbes and Fecal Metabolites in Mice Fed High-Fat Diet

Pu-erh tea is recognized for its weight loss effects, but its potential association with gut microbiota and metabolites remains unclear. This research explored the alterations in gut flora and metabolite composition upon treatment with a co-fermented Pu-erh tea with an aqueous corn silk extract (CPC) in obese mice by employing integrated 16S ribosomal RNA gene sequencing and untargeted metabolomics processes. For 8 weeks, mice were fed control, high-fat, and high-fat diets which included a 46 mg/mL CPC extract. The CPC extract the alleviated high-fat diet (HFD), it stimulated systemic chronic inflammation, and it reduced the body weight, daily energy consumption, and adipose tissue weight of the mice. It also modified the gut microbiota composition and modulated the Lactobacillus, Bifidobacterium, Allobaculum, Turicibacter, and Rikenella genera. Fecal metabolomics analysis revealed that the CPC extract influenced the caffeine, cysteine, methionine, tryptophan, biotin metabolism pathways, primary bile acid, and steroid biosynthesis. This research revealed that the CPC extract could inhibit HFD-stimulated abnormal weight gain and adipose tissue accumulation in mice, and modulate mice gut microbiota composition and multiple metabolic pathways.

Abdominal Massage Ameliorates Inguinal Fat Accumulation via Augmentation of PPARγ Signaling in High-Fat Diet-Induced Obese Mice

Purpose

With the increase in prevalence and decrease in age of the obese population, safer weight loss methods have attracted growing attention. While abdominal massage (AM) has been clinically proven for weight loss, the mechanism thereof has yet to be elucidated. We aimed to investigate the effect of AM on abdominal fat in obese mice fed a high-fat diet and explore the possible mechanisms involved.

Materials and Methods

Male C57BL/6J mice were fed a high-fat diet for 16 weeks and then treated with AM for 5 weeks; mice fed a standard diet were used as normal controls. Blood and adipose tissue, including inguinal white adipose tissue (WAT) and epididymal WAT, were collected from the mice after the intervention. We explored the mechanism of weight reduction through inguinal WAT transcriptome sequencing, quantitative real-time polymerase chain reaction (PCR) validation, and Western blot.

Results

The results revealed that AM decreased fat mass, weight, glucose, and serum lipid levels. Meanwhile, AM enhanced the expression of the peroxisome proliferator-activated receptor gamma (PPARγ) and other downstream genes (Fabp4, Acox3, Pck1, and Aqp7) in inguinal WAT. In addition, AM increased the expression of PPARγ protein.

Conclusion

AM may promote fatty acid oxidation, lipid metabolism, and glucose homeostasis by activating the PPARγ signaling pathway in inguinal WAT, thereby exhibiting therapeutic efficacy against obesity, even in the presence of a persistent high-fat diet.

Peroxisome Proliferator-Activated Receptor Signaling-Mediated 13-S-Hydroxyoctadecenoic Acid Is Involved in Lipid Metabolic Disorder and Oxidative Stress in the Liver of Freshwater Drum, Aplodinotus grunniens

The appropriate level of dietary lipids is essential for the nutrient requirements, rapid growth, and health maintenance of aquatic animals, while excessive dietary lipid intake will lead to lipid deposition and affect fish health. However, the symptoms of excessive lipid deposition in the liver of freshwater drums (Aplodinotus grunniens) remain unclear. In this study, a 4-month rearing experiment feeding with high-fat diets and a 6-week starvation stress experiment were conducted to evaluate the physiological alteration and underlying mechanism associated with lipid deposition in the liver of A. grunniens. From the results, high-fat-diet-induced lipid deposition was associated with increased condition factor (CF), viscerosomatic index (VSI), and hepatosomatic index (HSI). Meanwhile, lipid deposition led to physiological and metabolic disorders, inhibited antioxidant capacity, and exacerbated the burden of lipid metabolism. Lipid deposition promoted fatty acid synthesis but suppressed catabolism. Specifically, the transcriptome and metabolome showed significant enrichment of lipid metabolism and antioxidant pathways. In addition, the interaction analysis suggested that peroxisome proliferator-activated receptor (PPAR)-mediated 13-S-hydroxyoctadecenoic acid (13 (s)-HODE) could serve as the key target in regulating lipid metabolism and oxidative stress during lipid deposition in A. grunniens. Inversely, with a lipid intake restriction experiment, PPARs were confirmed to regulate lipid expenditure and physiological homeostasis in A. grunniens. These results uncover the molecular basis of and provide specific molecular targets for fatty liver control and prevention, which are of great importance for the sustainable development of A. grunniens.

Rice Bran Supplementation Ameliorates Gut Dysbiosis and Muscle Atrophy in Ovariectomized Mice Fed with a High-Fat Diet

Rice bran, a byproduct of rice milling, is rich in fiber and phytochemicals and confers several health benefits. However, its effects on gut microbiota and obesity-related muscle atrophy in postmenopausal status remain unclear. In this study, we investigated the effects of rice bran on gut microbiota, muscle synthesis, and breakdown pathways in estrogen-deficient ovariectomized (OVX) mice receiving a high-fat diet (HFD). ICR female mice were divided into five groups: sham, OVX mice receiving control diet (OC); OVX mice receiving HFD (OH); OVX mice receiving control diet and rice bran (OR); and OVX mice receiving HFD and rice bran (OHR). After twelve weeks, relative muscle mass and grip strength were high in rice bran diet groups. IL-6, TNF-α, MuRf-1, and atrogin-1 expression levels were lower, and Myog and GLUT4 were higher in the OHR group. Rice bran upregulated the expression of occludin and ZO-1 (gut tight junction proteins). The abundance of Akkermansiaceae in the cecum was relatively high in the OHR group. Our finding revealed that rice bran supplementation ameliorated gut barrier dysfunction and gut dysbiosis and also maintained muscle mass by downregulating the expression of MuRf-1 and atrogin-1 (muscle atrophy-related factors) in HFD-fed OVX mice.

Obesity-induced dysregulation of skin-resident PPARγ+ Treg cells promotes IL-17A-mediated psoriatic inflammation

Obesity is a major risk factor for psoriasis, but how obesity disrupts the regulatory mechanisms that keep skin inflammation in check is unclear. Here, we found that skin was enriched with a unique population of CD4+Foxp3+ regulatory T (Treg) cells expressing the nuclear receptor peroxisome proliferation-activated receptor gamma (PPARγ). PPARγ drove a distinctive transcriptional program and functional suppression of IL-17A+ γδ T cell-mediated psoriatic inflammation. Diet-induced obesity, however, resulted in a reduction of PPARγ+ skin Treg cells and a corresponding loss of control over IL-17A+ γδ T cell-mediated inflammation. Mechanistically, PPARγ+ skin Treg cells preferentially took up elevated levels of long-chain free fatty acids in obese mice, which led to cellular lipotoxicity, oxidative stress, and mitochondrial dysfunction. Harnessing the anti-inflammatory properties of these PPARγ+ skin Treg cells could have therapeutic potential for obesity-associated inflammatory skin diseases.

Gentiopicroside improves high-fat diet-induced NAFLD in association with modulation of host serum metabolome and gut microbiome in mice

Objective

The incidence of non-alcoholic fatty liver disease is increasing every year, and there is growing evidence that metabolites and intestinal bacteria play a causal role in NAFLD. Gentiopicroside, a major iridoids compound in gentian, has been reported to reduce hepatic lipid accumulation. However to date, no studies have confirmed whether the predominance of Gentiopicroside is related to metabolites and intestinal bacteria. Therefore, we sought to study whether the hypolipidemic effect of Gentiopicroside is related to metabolic function and intestinal flora regulation.

Methods

In the present study, C57BL/6J mice were fed a high-fat diet for 12 weeks, followed by a high-fat diet with or without Gentiopicroside for 8 weeks, respectively. The Gentiopicroside intervention reduced body weight gain, liver index, and decreased serum biochemical parameters such as alanine aminotransferase, aspartate aminotransferase, and triglycerides in high-fat fed mice. The effect of Gentiopicroside on non-alcoholic fatty liver disease was studied using serum untargeted metabolomics and 16S rDNA assay.

Results

Metabolomic analysis showed that the addition of Gentiopicroside significantly altered the levels of amino acids, unmetabolized Gentiopicroside after administration, and metabolites such as Cinnoline, Galabiosylceramide, and Tryptophyl-Tyrosine, which are involved in the pathways regulating bile secretion, tryptophan metabolism, and lipid metabolism. Analysis of intestinal bacteria showed that Gentiopicrosides altered the community composition structure of intestinal bacteria, characterized by an increase and a decrease in beneficial and harmful bacteria, respectively. In addition, correlation analysis showed that the effect of Gentiopicroside on metabolites was positively correlated with intestinal flora Bacteroides, Lactobacillus, Muribaculum, and Prevotellaceae_UCG_001. Finally, the combined analysis revealed that metabolites were associated with the regulation of Firmicutes and Actinobacteria and positively correlated with lipid levels.

Conclusion

These results suggest that Gentiopicroside may be a potential agent for the prevention of intestinal disorders and the alleviation of non-alcoholic fatty liver disease.

Anti-Diabetic and Anti-Adipogenic Effect of Harmine in High-Fat-Diet-Induced Diabetes in Mice

One of the most important health issues facing the world today is obesity. It is an important independent risk factor for developing type 2 diabetes. Harmine offers various pharmacological effects, such as anti-inflammatory and anti-tumor effects. The current study aims to investigate Harmine's anti-diabetic and anti-adipogenic properties in albino mice after inducing low-grade inflammation with a high-fat diet (HFD). About forty-eight male albino mice were divided into four groups. Group 1: control mice were injected with daily saline and fed a normal chow diet of 21% protein for 5 months. Group 2: mice were treated daily with IP-injected Harmine (30 mg/kg body weight) and were fed a normal chow diet for 5 months. Group 3: mice were fed HFD to induce type 2 Diabetes Mellitus (T2DM) for 5 months. Group 4: mice were fed HFD for 14 weeks and treated with Harmine for the last 6 weeks. A figh-fat diet caused a significant increase in body and organ weight, lipid profiles, and destructive changes within the pancreas, kidney, and liver tissue. The administration of Harmine led to a remarkable improvement in the histological and ultrastructural changes induced by HFD. The findings indicate that mice cured using Harmine had lower oxidative stress, a higher total antioxidant capacity, and a reduced lipid profile compared to HFD mice. Harmine led to the hepatocytes partly restoring their ordinary configuration. Furthermore, it was noticed that the pathological incidence of damage in the structure of both the kidney and pancreas sections reduced in comparison with the diabetic group. Additional research will be required to fully understand Harmine and its preventive effects on the two forms of diabetes.

Polystyrene Microplastics Exacerbate Systemic Inflammation in High-Fat Diet-Induced Obesity

Microplastics (MPs) are recognized as environmental pollutants with potential implications for human health. Considering the rapid increase in obesity rates despite stable caloric intake, there is a growing concern about the link between obesity and exposure to environmental pollutants, including MPs. In this study, we conducted a comprehensive investigation utilizing in silico, in vitro, and in vivo approaches to explore the brain distribution and physiological effects of MPs. Molecular docking simulations were performed to assess the binding affinity of three plastic polymers (ethylene, propylene, and styrene) to immune cells (macrophages, CD4+, and CD8+ lymphocytes). The results revealed that styrene exhibited the highest binding affinity for macrophages. Furthermore, in vitro experiments employing fluorescence-labeled PS-MPs (fPS-MPs) of 1 μm at various concentrations demonstrated a dose-dependent binding of fPS-MPs to BV2 murine microglial cells. Subsequent oral administration of fPS-MPs to high-fat diet-induced obese mice led to the co-existence of fPS-MPs with immune cells in the blood, exacerbating impaired glucose metabolism and insulin resistance and promoting systemic inflammation. Additionally, fPS-MPs were detected throughout the brain, with increased activation of microglia in the hypothalamus. These findings suggest that PS-MPs significantly contribute to the exacerbation of systemic inflammation in high-fat diet-induced obesity by activating peripheral and central inflammatory immune cells.

Effect of a High-Starch or a High-Fat Diet on the Milk Performance, Apparent Nutrient Digestibility, Hindgut Fermentation Parameters and Microbiota of Lactating Cows

In this study, changes in milk performance, nutrient digestibility, hindgut fermentation parameters and microflora were observed by inducing milk fat depression (MFD) in dairy cows fed with a high-starch or a high-fat diet. Eight Holstein cows were paired in a completely randomized cross-over design within two 35 d periods (18 d control period and 17d induction period). During the control period, all cows were fed the low-starch and low-fat diet (CON), and at the induction period, four of the cows were fed a high-starch diet with crushed wheat (IS), and the other cows were fed a high-fat diet with sunflower fat (IO). The results showed that, compared to when the cows were fed the CON diet, when cows were fed the IS or IO diet, they had lower milk fat concentrations, energy corrected milk, 3.5% fat-corrected milk yield, feed efficiency and apparent digestibility of NDF and ADF. However, cows fed the IO diet had a lower apparent digestibility of ether extracts. In addition, we observed that when cows were fed the high-starch (IS) or high-fat (IO) diet, they had a higher fecal concentration of propionate and acetate, and a lower NH3-N. Compared to when the cows were fed the CON diet, cows fed the IS diet had a lower pH, and cows fed the IO diet had a lower concentration of valerate in feces. In the hindgut microbiota, the relative abundance of Oscillospiraceae_UCG-005 was increased, while the Verrucomicrobiota and Lachnospiraceae_AC2044_group were decreased when cows were fed the IO diet. The relative abundance of Prevotellaceae_UCG-003 was increased, while the Alistipes and Verrucomicrobiota decreased, and the Treponema, Spirochaetota and Lachnospiraceae_AC2044_group showed a decreasing trend when cows were fed the IS diet. In summary, this study suggested that high-starch or high-fat feeding could induce MFD in dairy cows, and the high-fat diet had the greatest effect on milk fat; the high-starch or high-fat diet affected hindgut fermentation and apparent fiber digestibility. The changes in hindgut flora suggested that hindgut microbiota may be associated with MFD in cows.

Protaetia Brevitarsis-Derived Protein Hydrolysate Reduces Obesity-Related Colitis Induced by High-Fat Diet in Mice through Anti-Inflammatory Pathways

Ulcerative colitis is an inflammatory bowel disease characterized by inflammation in the mucosal and submucosal layers of the colon. Obesity is closely related to the occurrence and progression of colitis. The most plausible mechanism linking obesity and colitis is an excessive adipogenesis-related inflammatory response, which causes mucosal dysfunction. Obesity and colitis are linked by several etiologic mechanisms, including excessive adipogenesis, lipotoxicity, pro-inflammatory adipokines/cytokines, macrophage polarization, oxidative stress, endoplasmic reticulum (ER) stress, and gut microbiota. These low-grade enteric inflammations cause mucosal layer damage, especially goblet cell dysfunction through mucin 2 (MUC2) misfolding, ultimately leading to colitis. Inhibiting the inflammatory response can be the most effective approach for treating obesity-related colitis. We focused on the anti-inflammatory effects of polyphenols in Protaectia brevitas larvae. The P. brevitas was prepared as a low molecular protein hydrolysate (PHPB) to increase the concentration of anti-inflammatory molecules. In the current study, we investigated the anti-inflammatory effect of PHPB in an obesity-induced colitis mouse model. Compared with the high-fat diet (HFD) group, the group treated with PHPB exhibited reduced body/organ/fat weight, appetite/food intake inhibition, hypolipidemic effect on ectopic fat, and anti-adipogenic mechanism through the AMPK signaling pathway. Furthermore, we observed attenuated expression of PPARγ and C/EBPα, inhibition of pro-inflammatory molecules, stimulation of anti-inflammatory molecules, probiotic-like effect against obesogenic gut microbiota, inhibition of macrophage polarization into M1, suppression of oxidative/ER stress, and reduction of Muc2 protein misfolding in colon. These diverse anti-inflammatory responses caused histological and functional recovery of goblet cells, eventually improving colitis. Therefore, our findings suggest that the protein hydrolysate of Protaetia brevitarsis can improve obesity-related colitis through its anti-inflammatory activities.

Grape Polyphenols May Prevent High-Fat Diet-Induced Dampening of the Hypothalamic-Pituitary-Adrenal Axis in Male Mice

Context 

Chronic high-fat diet (HFD) consumption causes obesity associated with retention of bile acids (BAs) that suppress important regulatory axes, such as the hypothalamic-pituitary-adrenal axis (HPAA). HFD impairs nutrient sensing and energy balance due to a dampening of the HPAA and reduced production and peripheral metabolism of corticosterone (CORT).

Objective

We assessed whether proanthocyanidin-rich grape polyphenol (GP) extract can prevent HFD-induced energy imbalance and HPAA dysregulation.

Methods

Male C57BL6/J mice were fed HFD or HFD supplemented with 0.5% w/w GPs (HFD-GP) for 17 weeks.

Results

GP supplementation reduced body weight gain and liver fat while increasing circadian rhythms of energy expenditure and HPAA-regulating hormones, CORT, leptin, and PYY. GP-induced improvements were accompanied by reduced mRNA levels of Il6, Il1b, and Tnfa in ileal or hepatic tissues and lower cecal abundance of Firmicutes, including known BA metabolizers. GP-supplemented mice had lower concentrations of circulating BAs, including hydrophobic and HPAA-inhibiting BAs, but higher cecal levels of taurine-conjugated BAs antagonistic to farnesoid X receptor (FXR). Compared with HFD-fed mice, GP-supplemented mice had increased mRNA levels of hepatic Cyp7a1 and Cyp27a1, suggesting reduced FXR activation and more BA synthesis. GP-supplemented mice also had reduced hepatic Abcc3 and ileal Ibabp and Ostβ, indicative of less BA transfer into enterocytes and circulation. Relative to HFD-fed mice, CORT and BA metabolizing enzymes (Akr1d1 and Srd5a1) were increased, and Hsd11b1 was decreased in GP supplemented mice.

Conclusion

GPs may attenuate HFD-induced weight gain by improving hormonal control of the HPAA and inducing a BA profile with less cytotoxicity and HPAA inhibition, but greater FXR antagonism.

Apocynin alleviates weight gain and obesity-induced adipose tissue inflammation in high-fat diet-fed C57BL/6 mice

Obesity involves chronic low-grade inflammation within adipose tissue. Apocynin (APO) is a therapeutic agent for the treatment of inflammatory diseases. Therefore, the present study aimed to investigate whether APO can reduce weight gain and obesity-induced adipose tissue inflammation. C57BL/6 mice were administered APO or orlistat (Orli) as a positive control with a high-fat diet (HFD) for 12 weeks. Lipopolysaccharide-stimulated 3T3-L1 adipocytes were used for the in vitro study. Our results showed a significantly lower white adipose tissue (WAT) mass index in 10 mg/kg APO-treated mice than in 20 mg/kg Orli-treated mice. Moreover, the protein expression of adipose triglyceride lipase, fatty acid synthase, sterol regulatory element-binding transcription factor 1, and peroxisome proliferator-activated receptor γ was reversed in the WAT of 10 mg/kg APO-treated mice. Furthermore, APO reduced the expression of the macrophage marker F4/80, decreased the mRNA levels of tumor necrosis factor-α and monocyte chemoattractant protein-1, and increased the mRNA levels of interleukin-10 in WAT. APO decreased the phosphorylation of c-Jun N-terminal kinase, extracellular signal-regulated kinase, and p65 in vivo and in vitro. Notably, APO had a stronger effect on the amelioration of adipose tissue inflammation than Orli did. Our findings lay the foundation for research on the use of APO as an agent to ameliorate weight gain and obesity-induced inflammatory diseases.

Counteractive role of Terminalia catappa leaf extract on hematological and coagulation disturbance in Type 2 diabetic rats

Background and Aim

Diabetes mellitus is a leading cause of mortality worldwide associated with hyperglycemia-induced hematological aberrations and thromboembolic complications. This study aimed to explore the modulatory effect of Terminalia catappa leaf aqueous crude extract (TCLE) on hematological and coagulation disturbances in a Type 2 diabetic rat model.

Materials and Methods

High-fat diet streptozotocin-induced diabetic rats were treated orally with 400 and 800 mg/kg body weight TCLE daily for 28 days. Full blood count, coagulation parameters, plasma calcium (Ca), and erythrocyte glycogen (GLYC) levels were assessed using standard procedures.

Results

Terminalia catappa leaf aqueous crude extract treatment had a significant (p < 0.05) prolonging effect on clotting and bleeding times while increasing Ca, GLYC and mean corpuscular volume in diabetic rats. On the other hand, lymphocytes (LYM), platelet (PLT) count, mean PLT volume, neutrophil-LYM ratio (NLR), and PLT-LYM ratio (PLR) of TCLE-treated diabetic animals were significantly reduced (p < 0.05) compared with untreated diabetic animals. Lymphocyte, PLT count, NLR, and PLR correlated positively (p < 0.05) with plasma glucose, while a significant positive association was observed between Ca and GLYC. On the other hand, a strong negative association (p < 0.05) was observed between clotting time and fasting plasma glucose.

Conclusion

These findings suggest that T. catappa leaf extract may be useful in reversing diabetic-mediated hematological anomalies due to its anticoagulant and anti-anemic activities.

Prostaglandin E2 activates melanin-concentrating hormone neurons to drive diet-induced obesity

Hypothalamic inflammation reduces appetite and body weight during inflammatory diseases, while promoting weight gain when induced by high-fat diet (HFD). How hypothalamic inflammation can induce opposite energy balance outcomes remains unclear. We found that prostaglandin E2 (PGE2), a key hypothalamic inflammatory mediator of sickness, also mediates diet-induced obesity (DIO) by activating appetite-promoting melanin-concentrating hormone (MCH) neurons in the hypothalamus in rats and mice. The effect of PGE2 on MCH neurons is excitatory at low concentrations while inhibitory at high concentrations, indicating that these neurons can bidirectionally respond to varying levels of inflammation. During prolonged HFD, endogenous PGE2 depolarizes MCH neurons through an EP2 receptor-mediated inhibition of the electrogenic Na+/K+-ATPase. Disrupting this mechanism by genetic deletion of EP2 receptors on MCH neurons is protective against DIO and liver steatosis in male and female mice. Thus, an inflammatory mediator can directly stimulate appetite-promoting neurons to exacerbate DIO and fatty liver.

The time-dependent adverse effects of a high-fat diet on sperm parameters

BACKGROUND

Studies indicate a relationship between a high-fat diet (HFD) and sperm quality. However, the time-dependent adverse effects of a HFD on sperm parameters and the underlying mechanisms remain unclear.

OBJECTIVES

The present study was designed to determine the effects of a HFD on sperm quality at various time points in order to assess whether a HFD causes cumulative damage to sperm.

MATERIAL AND METHODS

Male C57BL/6 mice were fed a normal diet (the ND group) or a HFD (the HFD group) for 16, 30 or 42 weeks (n = 6 for each group). Body weight, lipid profile, sperm parameters, testicular morphology, and testicular oxidative stress levels were evaluated alongside the proliferation, DNA damage and rate of germ cell apoptosis.

RESULTS

Sperm quality was reduced in HFD-fed animals in a time-dependent manner, which was demonstrated by a decline in sperm density, motility and progressive motility. Further analysis showed a progressive deterioration of the testicular histoarchitecture of HFD-fed mice, which was accompanied by a decrease in DEAD-box helicase 4 (DDX4) expression and superoxide dismutase (SOD) levels, increased malondialdehyde (MDA) levels and gamma-H2A histone family member X (γ-H2AX) expression, and increased apoptosis of germ cells.

CONCLUSIONS

These findings demonstrate that a HFD exerted adverse effects on sperm quality, and the deteriorating effect was progressive with long-term feeding. The inhibited proliferation and apoptosis of germ cells, and the increased oxidative stress levels and DNA damage may be the underlying mechanisms.

Hepatic transcriptome signatures in mice and humans with nonalcoholic fatty liver disease

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) is the main reason for cirrhosis and hepatocellular carcinoma. As a starting point for NAFLD, the treatment of nonalcoholic fatty liver (NAFL) is receiving increasing attention. Mice fed a high-fat diet (HFD) and hereditary leptin deficiency (ob/ob) mice are important NAFL animal models. However, the comparison of these mouse models with human NAFL is still unclear.

METHODS

In this study, HFD-fed mice and ob/ob mice were used as NAFL animal models. Liver histopathological characteristics were compared, and liver transcriptome from both mouse models was performed using RNA sequencing (RNA-seq). RNA-seq data obtained from the livers of NAFL patients was downloaded from the GEO database. Global gene expression profiles in the livers were further analyzed using functional enrichment analysis and the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway.

RESULTS

Our results showed that the biochemical parameters of both mouse models and human NAFL were similar. Compared with HFD-fed mice, ob/ob mice were more similar in histologic appearance to NAFL patients. The liver transcriptome characteristics partly overlapped in mice and humans. Furthermore, in the NAFL pathway, most genes showed similar trends in mice and humans, thus demonstrating that both types of mice can be used as models for basic research on NAFL, considering the differences.

CONCLUSION

Our findings show that HFD-fed mice and ob/ob mice can mimic human NAFL partly in pathophysiological process. The comparative analysis of liver transcriptome profile in mouse models and human NAFL presented here provides insights into the molecular characteristics across these NAFL models.

Antiobesity Effect of N-Acetylneuraminic Acid by Enhancing Antioxidative Capacity in Mice Fed a High-Fat Diet

The sialic acid N-acetylneuraminic acid (NANA), an essential factor in bioregulation, is a functional food component that is known to have beneficial health effects, but its antiobesity effect has not been clearly understood. Adipocyte dysfunction in obesity involves a decrease in the level of NANA sialylation. In this study, we investigated the antiobesity effect of NANA in mice fed a high-fat diet (HFD) and in 3T3-L1 adipocytes. Male C57BL/6J mice were randomly divided into three groups and administered the following diets: a normal diet, an HFD, and an HFD with 1% NANA supplementation for 12 weeks. NANA supplementation significantly reduced body weight gain; epididymal adipose tissue hypertrophy; and serum lipid, fasting glucose, and aspartate transaminase levels compared with those in HFD mice. The percentage of lipid droplets in hepatic tissue was also decreased by NANA supplementation in HFD mice. The downregulation of Adipoq expression and upregulation of Fabp4 expression induced by HFD in epididymal adipocytes were improved by NANA supplementation. The downregulation of Sod1 expression and increase in malondialdehyde level were induced by HFD, and they were significantly improved in the liver by NANA supplementation, but not in epididymal adipocytes. However, NANA supplementation had no effect on sialylation and antioxidant enzyme levels in mouse epididymal adipocytes and 3T3-L1 adipocytes. Overall, NANA exerts antiobesity and antihypolipidemic effects and may be beneficial in suppressing obesity-related diseases.

Dietary fat differentially modulates the response of bone marrow-derived macrophages to TLR4 and NOD2 agonists

Consumption of diets high in fat has been linked to the development of obesity and related metabolic complications. Such associations originate from the enhanced, chronic, low-grade inflammation mediated by macrophages in response to translocated bacteria, bacterial products, or dietary constituents such as fatty acids (FAs). Nucleotide-binding Oligomerization Domain 2 (NOD2) senses muramyl dipeptide (MDP), a component of bacterial peptidoglycan. The inability to sense peptidoglycan through NOD2 has been demonstrated to lead to dysbiosis, increased bacterial translocation, inflammation and metabolic dysfunction. Currently, it is unknown how consumption of HFDs with different FA compositions might influence NOD2-dependent responses. In this study, we subjected WT mice to a control diet or to HFDs comprised of various ratios of unsaturated to saturated fats and determined the macrophage response to TLR4 and NOD2 agonists. A HFD with equal ratios of saturated and unsaturated fats enhanced subsequent responsiveness of macrophages to LPS but not to MDP. However, a high-unsaturated fat diet (HUFD) or a high-saturated fat diet (HSFD) both decreased the responsiveness to NOD2 agonists compared to that observed in control diet (CD) fed mice. These data suggest that dietary fatty acid composition can influence the subsequent macrophage responsiveness to bacterial products.

Lactiplantibacillus plantarum 06CC2 upregulates intestinal ZO-1 protein and bile acid metabolism in Balb/c mice fed high-fat diet

The effects of Lactiplantibacillus plantarum 06CC2 (LP06CC2), which was isolated from a Mongolian dairy product, on lipid metabolism and intestinal tight junction-related proteins in Balb/c mice fed a high-fat diet (HFD) were evaluated. The mice were fed the HFD for eight weeks, and the plasma and hepatic lipid parameters, as well as the intestinal tight junction-related factors, were evaluated. LP06CC2 slightly reduced the adipose tissue mass. Further, it dose-dependently decreased plasma total cholesterol (TC). The HFD tended to increase the plasma level of endotoxin and suppressed intestinal ZO-1 expression, whereas a low LP06CC2 dose increased ZO-1 expression and tended to reduce the plasma lipopolysaccharide level. Furthermore, a low LP06CC2 dose facilitated a moderate accumulation of Lactobacillales, a significant decrease in Clostridium cluster IV, and an increase in Clostridium cluster XVIII. The results obtained from analyzing the bile acids (BAs) in feces and cecum contents exhibited a decreasing trend for secondary and conjugated BAs in the low LP06CC2-dose group. Moreover, a high LP06CC2 dose caused excess accumulation of Lactobacillales and failed to increase intestinal ZO-1 and occludin expression, while the fecal butyrate level increased dose dependently in the LP06CC2-fed mice. Finally, an appropriate LP06CC2 dose protected the intestinal barrier function from the HFD and modulated BA metabolism.

Angiotensin II type 1a receptor knockout ameliorates high-fat diet-induced cardiac dysfunction by regulating glucose and lipid metabolism

Obesity-related cardiovascular diseases are associated with overactivation of the renin-angiotensin system (RAS). However, the underlying mechanisms remain elusive. In this study, we investigate the role of angiotensin II (Ang II) in high-fat diet (HFD)-induced cardiac dysfunction by focusing on cardiac glucose and lipid metabolism and energy supply. Ang II plays a role in cardiovascular regulation mainly by stimulating angiotensin II type 1 receptor (AT1R), among which AT1aR is the most important subtype in regulating the function of the cardiovascular system. AT1aR gene knockout (AT1aR ‒/‒) rats and wild-type (WT) rats are randomly divided into four groups and fed with either a normal diet (ND) or a HFD for 12 weeks. The myocardial lipid content, Ang II level and cardiac function are then evaluated. The expressions of a number of genes involved in glucose and fatty acid oxidation and mitochondrial dynamics are measured by quantitative polymerase chain reaction and western blot analysis. Our results demonstrate that AT1aR knockout improves HFD-induced insulin resistance and dyslipidemia as well as lipid deposition and left ventricular dysfunction compared with WT rats fed a HFD. In addition, after feeding with HFD, AT1aR ‒/‒ rats not only show further improvement in glucose and fatty acid oxidation but also have a reverse effect on increased mitochondrial fission proteins. In conclusion, AT1aR deficiency ameliorates HFD-induced cardiac dysfunction by enhancing glucose and fatty acid oxidation, regulating mitochondrial dynamics-related protein changes, and further promoting cardiac energy supply.

Corrigendum: Revealing the mechanism of Huazhi Rougan granule in the treatment of nonalcoholic fatty liver through intestinal flora based on 16S rRNA, metagenomic sequencing and network pharmacology

[This corrects the article DOI: 10.3389/fphar.2022.875700.].