The Ameliorative Effect and Mechanisms of Ruditapes philippinarum Bioactive Peptides on Obesity and Hyperlipidemia Induced by a High-Fat Diet in Mice

Interplay of Food-Derived Bioactive Peptides with Gut Microbiota: Implications for Health and Disease Management

Bioactive peptides (BPs) are protein fragments with beneficial effects on metabolism, physiology, and diseases. This review focuses on proteolytic BPs, which are produced by the action of gut microbiota on proteins in food and have demonstrated to influence the composition of gut microbes. And gut microbiota are candidate targets of BPs to alleviate oxidative stress, enhance immunity, and control diseases, including diabetes, hypertension, obesity, cancer, and immune and neurodegenerative diseases. Despite promising results, further research is needed to understand the mechanisms underlying the interactions between BPs and gut microbes, and to identify and screen more BPs for industrial applications. Overall, BPs offer potential as therapeutic agents for various diseases through their interactions with gut microbes, highlighting the importance of continued research in this area.

Anti-obesity and anti-diabetic bioactive peptides: A comprehensive review of their sources, properties, and techno-functional challenges

The scourge of obesity arising from obesogens and poor dieting still ravages our planet as half of the global population may be overweight and obese by 2035. This metabolic disorder is intertwined with type 2 diabetes (T2D), both of which warrant alternative therapeutic options other than clinically approved drugs like orlistat with their tendency of abuse and side effects. In this review, we comprehensively describe the global obesity problem and its connection to T2D. Obesity, overconsumption of fats, the mechanism of fat digestion, obesogenic gut microbiota, inhibition of fat digestion, and natural anti-obesity compounds are discussed. Similar discussions are made for diabetes with regard to glucose regulation, the diabetic gut microbiota, and insulinotropic compounds. The sources and production of anti-obesity bioactive peptides (AOBPs) and anti-diabetic bioactive peptides (ADBPs) are also described while explaining their structure-function relationships, gastrointestinal behaviors, and action mechanisms. Finally, the techno-functional applications of AOBPs and ADBPs are highlighted.

Structural and functional alteration of the gut microbiota in elderly patients with hyperlipidemia

Objective

To investigate the structure, composition, and functions of the gut microbiota in elderly patients with hyperlipidemia.

Methods

Sixteen older patients diagnosed with hyperlipidemia (M group) and 10 healthy, age-matched normal volunteers (N group) were included. These groups were further subdivided by sex into the male normal (NM, n = 5), female normal (NF, n = 5), male hyperlipidemia (MM, n = 8), and female hyperlipidemia (MF, n = 8) subgroups. Stool samples were collected for high-throughput sequencing of 16S rRNA genes. Blood samples were collected for clinical biochemical index testing.

Results

Alpha- and beta-diversity analyses revealed that the structure and composition of the gut microbiota were significantly different between the M and N groups. The relative abundances of Bacteroides, Parabacteroides, Blautia, Peptococcus, and Bifidobacterium were significantly decreased, while those of Lactobacillus, Helicobacter, and Desulfovibrio were significantly higher in the M group. There were also significant sex-related differences in microbial structure between the NM and NF groups, and between the MM and MF groups. Through functional prediction with PICRUSt 2, we observed distinct between-group variations in metabolic pathways associated with the gut microbiota and their impact on the functionality of the nervous system. Pearson's correlation coefficient was used as a distance metric to build co-abundance networks. A hypergeometric test was used to detect taxonomies with significant enrichment in specific clusters. We speculated that modules with Muribaculaceae and Lachnospiraceae as the core microbes play an important ecological role in the intestinal microbiota of the M group. The relative intestinal abundances of Agathobacter and Faecalibacterium in the M group were positively correlated with serum triglyceride and low-density lipoprotein levels, while the relative abundance of Bifidobacterium was negatively correlated with the serum lipoprotein a level.

Androgens exacerbate hepatic triglyceride accumulation in rats with polycystic ovary syndrome by downregulating MTTP expression

PURPOSE

Polycystic ovary syndrome (PCOS) is a common reproductive endocrine disorder, which is closely associated with insulin resistance, glucose and lipid metabolism disorders. Patients with PCOS have a significantly higher risk of non-alcoholic fatty liver disease and are associated with hyperandrogenemia (HA). However, the exact mechanism by which HA exacerbates hepatic steatosis in PCOS has not yet been fully elucidated. This work aims to investigate the effects and underlying mechanisms of androgens on hepatic triglyceride (TG) metabolism in rats with PCOS.

METHODS

Twenty-four female Sprague-Dawley rats were randomly divided into four groups (6 rats/group): control, high-fat diet (HFD), PCOS, and PCOS + flutamide (Flu). Changes in the estrous cycle, liver and ovarian tissue sections, serum total testosterone, serum and liver biochemical indicators, and key enzymes involved in TG metabolism were studied.

RESULTS

Hepatocyte steatosis and TG accumulation were more evident in the PCOS group than in the control and HFD groups. The PCOS group showed apparent increases in the levels of serum alanine aminotransferase, aspartate aminotransferase, TG, free fatty acid, fasting insulin, and homeostasis model assessment of insulin resistance. Hepatic VLDL and apoB-100 levels decreased in the PCOS group. After Flu was administered to block the actions of androgens, the above abnormalities had been improved. The expression of MTTP was greatly decreased in the PCOS group and significantly increased after Flu administration.

CONCLUSION

Hepatic steatosis in PCOS rats was correlated with HA. Androgens may exacerbate hepatic TG accumulation by downregulating MTTP expression in PCOS.

Leucine improves thiram-induced tibial dyschondroplasia and gut microbiota dysbiosis in broilers

Thiram, a commonly used agricultural insecticide and fungicide, has been found to cause tibial dyschondroplasia (TD) in broilers, leading to substantial economic losses in the poultry industry. In this study, we aimed to investigate the mechanism of action of leucine in mitigating thiram-induced TD and leucine effects on gut microbial diversity. Broiler chickens were randomly divided into five equal groups: control group (standard diet), thiram-induced group (thiram 80 mg/kg from day 3 to day 7), and different concentrations of leucine groups (0.3%, 0.6%, 0.9% leucine from day 8 to day 18). Performance indicator analysis and tibial parameter analysis showed that leucine positively affected thiram-induced TD broilers. Additionally, mRNA expressions and protein levels of HIF-1α/VEGFA and Ihh/PTHrP genes were determined via quantitative real-time polymerase chain reaction and western blot. The results showed that leucine recovered lameness disorder by downregulating the expression of HIF-1α, VEGFA, and PTHrP while upregulating the expression of Ihh. Moreover, the 16 S rRNA sequencing revealed that the leucine group demonstrated a decrease in the abundance of harmful bacteria compared to the TD group, with an enrichment of beneficial bacteria responsible for producing short-chain fatty acids, including Alistipes, Paludicola, CHKCI002, Lactobacillus, and Erysipelatoclostridium. In summary, the current study suggests that leucine could improve the symptoms of thiram-induced TD and maintain gut microbiota homeostasis.

Effects of different levels of Citri Sarcodactylis Fructus by-products fermented feed on growth performance, serum biochemical, and intestinal health of cyan-shank partridge birds

This research aimed to investigate the effects of supplements containing fermented feed made from Citri Sarcodactylis Fructus by-products (CSFBP-Fermented feed) on the growth performance, immunological function, and gut health of broilers. 1080 cyan-shank partridge birds aged 47 days were chosen and casually distributed to four groups, each with 6 replicates and 45 birds per replicate. The experimental groups were provided with 1% (group T2), 3% (group T3) and 5% (group T4) of CSFBP-fermented feed in the basic diet, while the control group (group T1) received the basic diet. The findings revealed that supplementation with CSFBP-Fermented feed reduced ADFI and FCR and improved ADG in birds (P < 0.05). MDA levels in the serum of birds fed CSFBP-fermented feed were lower than in the control group (P < 0.05). The CAT activity in the serum of broilers increased after supplementation with 3% CSFBP-Fermented feed (P < 0.05). Supplementing broilers with CSFBP-fermented feed enhanced VH in the ileum, jejunum, and duodenum (P < 0.05). The addition of 3% CSFBP-Fermented feed decreased CD in the jejunum (P < 0.05). The addition of 3% and 5% CSFBP-Fermented feed increased the mRNA expression of ZO-1 and Occludin in the jejunum of broiler chickens and reduced the mRNA expression of IL-6 (P < 0.05). The addition of 3% CSFBP-Fermented feed increased the mRNA expression of Claudin in the jejunum of broiler chickens and reduced IL-1β mRNA expression (P < 0.05). Compared to the control group, all experimental groups exhibited decreased mRNA expression of TNF-α and INF-γ in the jejunal mucosa of the birds (P < 0.05). According to research using high-throughput sequencing of microorganisms' 16S rDNA, and an analysis of α-diversity found that supplementing broilers with 3% CSFBP-Fermented feed decreased the number of bacteria in their cecum (P < 0.05). Bacteroidota was higher in all groups after supplementation with CSFBP-Fermented feed. At the genus level, after addition with 3% CSFBP-Fermented feed, the abundance of Bacteroide and Prevotellaceae_Ga6A1_group were higher than the control group (33.36% vs 29.95%, 4.35% vs 2.94%). The abundance of Rikenellaceae_RC9_gut_group and Fusobacterium were lower than the control group (5.52% vs. 7.17%,0.38% vs. 1.33%). In summary, supplementing the diet with CSFBP-Fermented feed can promote the growth of performance by enhancing intestinal morphology, and barrier function, as well as modulating intestinal inflammatory factors and microbial composition in broilers.

Bioactive Peptides from Ruditapes philippinarum Attenuate Hypertension and Cardiorenal Damage in Deoxycorticosterone Acetate-Salt Hypertensive Rats

Hypertension is a common disease that affects human health and can lead to damage to the heart, kidneys, and other important organs. In this study, we investigated the regulatory effects of bioactive peptides derived from Ruditapes philippinarum (RPP) on hypertension and organ protection in deoxycorticosterone acetate (DOCA)-salt hypertensive rats. We found that RPPs exhibited significant blood pressure-lowering properties. Furthermore, the results showed that RPPs positively influenced vascular remodeling and effectively maintained a balanced water-sodium equilibrium. Meanwhile, RPPs demonstrated anti-inflammatory potential by reducing the serum levels of inflammatory cytokines (TNF-α, IL-2, and IL-6). Moreover, we observed the strong antioxidant activity of RPPs, which played a critical role in reducing oxidative stress and alleviating hypertension-induced damage to the aorta, heart, and kidneys. Additionally, our study explored the regulatory effects of RPPs on the gut microbiota, suggesting a possible correlation between their antihypertensive effects and the modulation of gut microbiota. Our previous studies have demonstrated that RPPs can significantly reduce blood pressure in SHR rats. This suggests that RPPs can significantly improve both essential hypertension and DOAC-salt-induced secondary hypertension and can ameliorate cardiorenal damage caused by hypertension. These findings further support the possibility of RPPs as an active ingredient in functional anti-hypertensive foods.

Therapeutic impact of stachyose on hyperlipidaemia caused by a high-fat diet in mice as revealed by gut microbiota and metabolomics

Hyperlipidaemia, which is characterized by an excess of lipids or fats in the bloodstream, is a high-risk factor and critical indicator of many metabolic diseases. This study used 16 S rRNA gene sequencing and metabolomics to determine that stachyose (ST) has a therapeutic effect and is a mechanism of hyperlipidaemia. These results show that ST significantly attenuated high-fat diet-induced weight gain and fat deposition while also adjusting the gut microbial composition. Untargeted serum metabolomics identified 12 biomarkers, which suggests that ST may function by regulating metabolic pathways. These results highlight the potential of ST in treating hyperlipidaemia and provides directions for future research including an in-depth investigation of the bioactive components, dosage, and treatment strategies of ST.

Lactobacillus fermentum CKCC1858 alleviates hyperlipidemia in golden hamsters on a high-fat diet via modulating gut microbiota

To investigate the effect of probiotic Lactobacillus fermentum CKCC1858, LF on the prevention of hyperlipidemia and its correlation with gut microbiota, golden hamsters were fed a high-fat diet alone or in combination with the probiotic for 6 weeks. The results showed that the LF intervention alleviated HFD-induced hyperlipidemia and liver damage, as evidenced by the reduced serum lipid profile levels and liver function markers. More importantly, the LF intervention attenuated HFD-induced microbiota dysbiosis by enhancing the abundance of SCFA-producing bacteria and reshaping the metabolic functions of the gut microbiota, likely contributing to its pronounced preventive effects on hyperlipidemia. This study elucidated the mechanism of the preventive effect of probiotics on hyperlipidemia in terms of regulating gut microbiota, and provided suggestions for regulating gut microbiota through probiotic interventions to improve lipid metabolism.

Farnesoid X receptor is an important target for the treatment of disorders of bile acid and fatty acid metabolism in mice with nonalcoholic fatty liver disease combined with cholestasis

BACKGROUND AND AIM

The prevalence of nonalcoholic fatty liver disease (NAFLD) has been rising globally. NAFLD patients combined with cholestasis have more obvious liver fibrosis, impaired bile acid (BA), and fatty acid (FA) metabolism and severer liver injury; however, its therapeutic options are limited, and the underlying metabolic mechanisms are understood. Here, we aimed to investigate the effects of farnesoid X receptor (FXR) on BA and FA metabolism in NAFLD combined with cholestasis and related signaling pathways.

METHODS

A mouse model of NAFLD combined with cholestasis was established by joint intervention with high-fat diet (HFD) and alpha-naphthylisothiocyanate. The effects of FXR on BA and FA metabolism were evaluated by serum biochemical analysis. Liver damage was identified by histopathology. The expression of nuclear hormone receptor, membrane receptor, FA transmembrane transporter, and BA transporter protein in mice were measured by western blot.

RESULTS

NAFLD mice combined with cholestasis developed more severe cholestasis and dysregulated BA and FA metabolism. Meanwhile, the expression of FXR protein was decreased in NAFLD mice combined with cholestasis compared to the controls. Fxr-/- mice showed liver injury. HFD aggravated the liver injury with decreased BSEP expression, increased expression of NTCP, LXRα, SREBP-1c, FAS, ACC1, and CD36, and significantly increased BA and FA accumulation.

CONCLUSION

All the results suggested that FXR plays a key role in both FA and BA metabolism in NAFLD combined with cholestasis and thus may be a potential target for the treatment of disorders of BA and FA metabolism in NAFLD combined with cholestasis.

Liver Lipidomics Analysis Revealed the Novel Ameliorative Mechanisms of L-Carnitine on High-Fat Diet-Induced NAFLD Mice

The beneficial effects of L-carnitine on non-alcoholic fatty liver disease (NAFLD) were revealed in previous reports. However, the underlying mechanisms remain unclear. In this study, we established a high fat diet (HFD)-induced NAFLD mice model and systematically explored the effects and mechanisms of dietary L-carnitine supplementation (0.2% to 4%) on NAFLD. A lipidomics approach was conducted to identify specific lipid species involved in the ameliorative roles of L-carnitine in NAFLD. Compared with a normal control group, the body weight, liver weight, concentrations of TG in the liver and serum AST and ALT levels were dramatically increased by HFD feeding (p < 0.05), accompanied with obvious liver damage and the activation of the hepatic TLR4/NF-κB/NLRP3 inflammatory pathway. L-carnitine treatment significantly improved these phenomena and exhibited a clear dose–response relationship. The results of a liver lipidomics analysis showed that a total of 12 classes and 145 lipid species were identified in the livers. Serious disorders in lipid profiles were noticed in the livers of the HFD-fed mice, such as an increased relative abundance of TG and a decreased relative abundance of PC, PE, PI, LPC, LPE, Cer and SM (p < 0.05). The relative contents of PC and PI were significantly increased and that of DG were decreased after the 4% L-carnitine intervention (p < 0.05). Moreover, we identified 47 important differential lipid species that notably separated the experimental groups based on VIP ≥ 1 and p < 0.05. The results of a pathway analysis showed that L-carnitine inhibited the glycerolipid metabolism pathway and activated the pathways of alpha-linolenic acid metabolism, glycerophospholipid metabolism, sphingolipid metabolism and Glycosylphosphatidylinositol (GPI)-anchor biosynthesis. This study provides novel insights into the mechanisms of L-carnitine in attenuating NAFLD.