High-protein diet prevents fat mass increase after dieting by counteracting Lactobacillus-enhanced lipid absorption

Gut microbiota-derived 4-hydroxyphenylacetic acid from resveratrol supplementation prevents obesity through SIRT1 signaling activation

Resveratrol (RSV), a natural polyphenol, has been suggested to influence glucose and lipid metabolism. However, the underlying molecular mechanism of its action remains largely unknown due to its multiple biological targets and low bioavailability. In this study, we demonstrate that RSV supplementation ameliorates high-fat-diet (HFD)-induced gut microbiota dysbiosis, enhancing the abundance of anti-obesity bacterial strains such as Akkermansia, Bacteroides and Blautia. The critical role of gut microbiota in RSV-mediated anti-obesity effects was confirmed through antibiotic-induced microbiome depletion and fecal microbiota transplantation (FMT), which showed that RSV treatment effectively mitigates body weight, histopathological damage, glucose dysregulation and systematic inflammation associated with HFD. Metabolomics analysis revealed that RSV supplementation significantly increases the levels of the gut microbial flavonoid catabolite 4-hydroxyphenylacetic acid (4-HPA). Notably, 4-HPA was sufficient to reverse obesity and glucose intolerance in HFD-fed mice. Mechanistically,4-HPA treatment markedly regulates SIRT1 signaling pathways and induces the expression of beige fat and thermogenesis-specific markers in white adipose tissue (WAT). These beneficial effects of 4-HPA are partially abolished by EX527, a known SIRT1 inhibitor. Collectively, our findings indicate that RSV improve obesity through a gut microbiota-derived 4-HPA-SIRT1 axis, highlighting gut microbiota metabolites as a promising target for obesity prevention.

Tea polyphenol EGCG enhances the improvements of calorie restriction on hepatic steatosis and obesity while reducing its adverse outcomes in obese rats

BACKGROUND

Currently, calorie restriction (CR) is popular among young people as a way to lose weight and prevent obesity. However, CR can also cause a series of side effects, such as weight regain after resuming free eating. Tea polyphenol epigallocatechin-3-gallate (EGCG) has been widely recognized as antiobesity effects. However, whether EGCG can enhance the antiobesity effect of CR and reduce its adverse outcomes is still unclear.

PURPOSE

This study aimed to explore the enhancing effect and molecular mechanism of EGCG supplementation on CR in improving hepatic steatosis and obesity.

METHODS

The enhancing effect and molecular mechanism of EGCG supplementation on CR in alleviating hepatic steatosis and obesity were explored using a leptin receptor-knockout (LepR KO) rat model by performing biochemical, histochemistry, qPCR, plasma lipidomic, and gut microbiota analysis.

RESULTS

Our results showed that CR plus EGCG exhibited enhanced preventive effects in reducing blood glucose, insulin, TC, TG, LDL-C, and FFA levels in plasma, and protection against hepatic steatosis in LepR KO rats than CR alone. In addition, CR plus EGCG remarkably reduced oxidative stress and systemic inflammatory responses in LepR KO rats. Moreover, the combined intervention showed an enhanced improvement effect on the homeostasis of gut microbiota than CR alone, including increasing gut microbiota diversity and modulating microbiota composition. Plasma lipidomics analysis showed that CR plus EGCG significantly improved glycerophospholipid, glycerolipid and sphingolipid metabolism in LepR KO rats. Mechanistic studies showed that CR combined EGCG enhanced SIRT6 and suppressed SREBP1 and FAS expression in the livers of LepR KO rats than CR alone, thereby improving host lipid metabolism.

CONCLUSION

This study demonstrated that EGCG enhance the improvements of CR on hepatic steatosis and obesity in LepR KO rats, and reduce its adverse outcomes, especially in reducing hepatic lipogenesis and maintaining homeostasis of gut microbiota. This study provides a dietary strategy for preventing weight rebound following the transition from CR to a free diet by supplementing EGCG, suggesting that CR plus EGCG may offer a promising therapy for managing obesity in humans.

Moderate dietary restriction across generations promotes sustained health and extends lifespan by enhancing antioxidant capacity in Bombyx mori

Moderate dietary restriction (DR) is known to extend lifespan, but its long-term safety remains unclear. In this study, silkworms of P50 were divided into libitum feeding (AL) and DR groups, with the DR group receiving 65% of the AL group's intake. Using the contemporary DR cohort as the parent generation, the identical dietary restriction methodology is perpetuated across successive generations to establish a multi-generational DR model. We recorded body weight, lifespan, spawning amount, and cocoon shell rate at each generation, and analyzed tissue sections of the G6 generation. Biochemical indices of hemolymph were assessed in the G0 and G3 generations, and the expression levels of genes associated with DR metabolism were analyzed using quantitative PCR. The result showed that DR initially caused weight loss, which then stabilized, and significantly extended lifespan. Biochemical indicators showed that silkworm's antioxidant capacity improved significantly in DR group, with notable differences between the current (G0) and successive (G3) generations. Gene expression related to oxidative stress was significantly altered depending on there function in G3 compared to G0. This suggests that long-term moderate DR can extend lifespan and reduce weight and fat, mainly due to enhanced antioxidant capacity. Additionally, animals demonstrated adaptability to prolonged moderate DR, indicating its feasibility across generations in insects. Our study confirms that boosting antioxidant capacity is a healthy, life-extending strategy under dietary restriction and highlights the adaptability of animals to such diets over generations, supporting the development of safe, long-term dietary plans for humans and large animals.

Potential of queen bee larvae as a dietary supplement for obesity management: modulating the gut microbiota and promoting liver lipid metabolism

Queen bee larvae (QBL) have been consumed as both a traditional food and medicine in China for thousands of years; however, their specific benefits for human health, particularly their potential anti-obesity property, remain underexplored. This study investigated the anti-obesity effect of QBL freeze-dried powder (QBLF) on high-fat diet (HFD) induced obesity in mice and explored the underlying mechanisms. Our findings showed that QBLF effectively reduced body weight, fasting blood glucose levels, lipid accumulation, and inflammation in HFD mice. 16S rRNA sequencing revealed that QBLF significantly modulated the gut microbiota disrupted by an HFD, notably increasing the relative abundance of beneficial microbes such as Ileibacterium, Clostridium sensu stricto 1, Incertae sedis, Streptococcus, Lactococcus, Clostridia UCG-014, and Lachnospiraceae UCG-006, which were inversely associated with obesity-related phenotypes in the mice. RNA sequencing analysis further demonstrated that QBLF intervention upregulated the expression of genes involved in liver lipid metabolism, including Pck1, Cyp4a10, Cyp4a14, and G6pc, while downregulating genes associated with the inflammatory response, such as Cxcl10, Ccl2, Traf1, Mapk15, Lcn2, and Fosb. These results suggested that QBLF can ameliorate HFD-induced obesity through regulating the gut microbiota, promoting liver lipid metabolism, and reducing inflammatory response.

Comparative microbiomic analysis of fecal microbiota associated with abdominal fat in ducks

The gut microbiota, which features complex community structures, colonizes the duck intestine and plays a crucial role in metabolism, immune regulation, and meat quality. Gut-microbiota-regulated abdominal fat deposition is a key factor that affects the meat quality of livestock and poultry. We used 16S rDNA and metagenomic sequencing to investigate the microbial community characteristics of 187 fecal samples from 10 Chinese indigenous duck breeds (five breeds for each of the high/low abdominal fat categories). We explored the relationship between fecal microbiota and abdominal fat deposition. The α diversity of the fecal microbiome in high abdominal fat ducks (HAF) was higher than that in low abdominal fat ducks (LAF). The fecal microbiota and function were also significantly different. At the phylum level, Actinobacteria was significantly enriched in HAF, whereas Proteobacteria, Candidatus, Saccharibacteria, and Fusobacteria were abundant in LAF. At the genus level, Lactobacillus, Alistipes, Corynebacterium, and Lachnoclostridium were more abundant in HAF than in LAF. The Streptococcus, Campylobacter, Helicobacter, Enterobacter, Gallibacterium, and Escherichia genera were significantly enriched in LAF. Microbial functional analysis indicated that the HAF fecal microbiota was mainly involved in carbohydrate, nucleotide, lipid, amino acid, terpenoids, polyketides, and xenobiotic metabolism. In addition, bacteria related to signal transduction, cofactor and vitamin metabolism, and infectious disease were enriched in LAF. This study revealed the relationship between gut microbiota and abdominal fat deposition in ducks. Our findings lay a foundation for the abdominal fat deposition mechanism in ducks and provide a reference for Chinese indigenous duck husbandry.

Fecal microbiota transplantation improves growth performance of chickens by increasing the intestinal Lactobacillus and glutamine

Chicken meat is an essential source of high-quality animal protein, mainly derived from slow-growth chicken (SC) and fast-growth chicken (FC) breeds. Skeletal muscle is a highly adaptable tissue that is influenced by breed differences and the gut microbiome. Investigation whether remodeling the gut microbiota by fecal microbiota transplantation (FMT) improves chicken growth is an interesting question. We compared the gut microbial composition of eight breeds of SC (Xinghua chicken, Yangshan chicken, Zhongshan Salan chicken, Qingyuan Partridge chicken, Huiyang Bearded chicken and Huaixiang chicken) and FC (Xiaobai chicken and White rock chicken). Fecal microbiota from donor FC (Xiaobai chickens) with superior growth performance were transferred to SC (Xinghua chickens). The effects of FMT on growth performance, metabolic profile and gut microbiome of recipient chickens were evaluated. We found significant differences in gut microbial composition, with a higher abundance of Bacteroidetes in SC and a higher abundance of Firmicutes in FC. Xiaobai chickens with better growth performance and abundant Lactobacillus, and FMT significantly enhanced growth performance, the expression of mRNA (MYOG, MYF5, MYF6 and IGF1) related to breast and leg muscle development and improved the villus/crypt ratio in the jejunum. FMT altered the microbiota in the duodenum, jejunum, and ileum, increased Lactobacillus abundance, decreased the relative mRNA expression of the intestinal inflammatory factors (IL-1β, IL-6 and TNF-α), increased glutamine levels in the host, including in muscle tissues and intestinal contents, and Spearman correlation analysis indicated that the relative abundance of Lactobacillus was positively correlated with glutamine levels. Additionally, antibiotic treatment reduces glutamine levels in the intestines, blood, and muscle tissues of chickens. Glutamine can increase the expression of cyclinD1, cyclinD2, cyclinB2, MYOG, MYF5, MYF6 and IGF1 mRNA to promote chicken myoblasts proliferation and differentiation. This study found that the SC and FC gut microbes were significantly different, and the FC chicken gut microbes were able to reshape the FC gut microbiota through FMT, i.e., higher Lactobacillus, promoted chicken myoblasts proliferation and differentiation and growth performance by increasing glutamine levels.

Uncovering the heterogeneity of the gut microbial taxa associated with the contents of different fatty acids in muscle with cecum luminal content and fecal samples from two pig populations

Fatty acids in pork are involved in cellular physiological functions and related to meat nutrition, tenderness, and flavor. Increasing evidences have suggested that short-chain fatty acids produced by the gut microbiota may affect host metabolism and energy utilization. However, the association between gut microbiota and long-chain fatty acids (LCFAs) in pork has been largely unknown. In this study, the microbial compositions of 243 cecum content samples from Erhualian pigs and 235 fecal samples from Bamaxiang pigs were determined by high throughput 16S rRNA gene sequencing. The contents of 12 LCFAs in longissimus dorsi (LD) muscle were also determined for all experimental pigs of both pig populations. We systematically evaluated the contribution of gut microbiota to the variations of muscle fatty acid contents from the α-diversity of gut microbiota, co-abundance groups (CAGs) of Amplicon Sequence Variants (ASVs), and fatty acid-associated bacterial taxa. We identified hundred ASVs and > 40 bacterial taxa that were significantly associated with muscle fatty acid contents in two pig populations. Different numbers and bacterial taxa associated with the content of specific LCFAs in muscle were detected between cecum luminal content and fecal samples, suggesting the heterogeneity of the specific LCFA-associated bacterial taxa between two gut locations. We uncovered some interesting associations between bacterial taxa and muscle fatty acid contents. The strongest association was observed between the ASV annotated to Akkermansia and the n-6/n-3 polyunsaturated fatty acid ratio (p = 6.45E-04, Z = -9.65). The gut microbiota could explain 1.47-4.62% variation of muscle contents of twelve fatty acids. The functional prediction analysis identified that the KEGG pathways related to the metabolisms of carbohydrate and lipids, and to fat digestion and absorption were positively associated with the contents of muscle fatty acids. However, adipocytokine signaling pathway and thermogenesis were negatively associated with muscle fatty acid contents. The results from this study provided the basic knowledge for improving the muscle fatty acid contents by regulating the gut microbiome.

Metabolome and RNA-seq reveal discrepant metabolism and secretory metabolism profile in skeletal muscle between obese and lean pigs at different ages

Metabolites and metabolism-related gene expression profiles in skeletal muscle change dramatically under obesity, aging and metabolic disease. Since obese and lean pigs are ideal models for metabolic research. Here, we compared metabolome and transcriptome of Longissimus dorsi (LD) muscle between Taoyuan black (TB, obese) and Duroc (lean) pigs at different ages. We defined the "window phase" of intramuscular fat (IMF) deposition in TB pig, which has significantly higher IMF than Duroc pig. Our results displayed discrepant lipid composition and different expression genes (DEGs) enriched in lipid metabolism, and both metabolome and transcriptome analyses revealed stronger energy expenditure and more active amino acid and protein metabolism in Duroc pig. 10 up- and 51 down-regulated biomarker metabolites with age- and breed-specificity were identified. Potential secretory metabolites, including organic acid (fumaric acid, succinate, malic acid, and gamma-aminobutyric acid), amino acid (L-lysine, and L-glutamic acid), lipid (2-hydroxyisovaleric acid, and L-carnitine) were demonstrated a significant correlation with IMF deposition. Our research highlights the huge difference of metabolic spectrum in skeletal muscle between obese and lean model and muscle-derived secretory metabolites might act as an ambassador of intercellular communication to regulate systematic metabolism.

Weight Management for Fertility-Preservation Therapy in Endometrial Cancer: Opportunities and Challenges

PURPOSE OF REVIEW

Obesity is increasingly recognized as a significant factor impacting the outcomes of fertility-preserving therapies for endometrial cancer (EC). This review explores the effects of glycolipid metabolism on EC and its relationship with body weight. We will examine how excess body weight influences the effectiveness of fertility-preserving treatments and discuss potential mechanisms for effective weight management. Additionally, the review highlights the importance of comprehensive weight management as an adjunct strategy to enhance the efficacy of fertility-preserving interventions, providing insights into how to integrate metabolic health into clinical treatment protocols.

RECENT FINDINGS

Weight management can modify the tumor microenvironment by depriving the tumor of nutrients, whereas exercise can enhance immunity, potentially leading to tumor cell death. In addition, progesterone therapy may impede the proliferation of EC cells. Comprehensive weight management can serve as an essential adjuvant treatment for patients undergoing fertility-preserving therapies for EC. In this review, we highlight that comprehensive weight management can serve as a crucial adjuvant treatment for patients undergoing fertility-preserving therapies for endometrial cancer. Targeting glycolipid metabolism and addressing adiposity can improve hormonal balance, reduce inflammation, and enhance fertility outcomes. Further research is necessary to establish specific protocols and evaluate the effectiveness of these strategies in clinical practice.

Quercetin-Driven Akkermansia Muciniphila Alleviates Obesity by Modulating Bile Acid Metabolism via an ILA/m6A/CYP8B1 Signaling

Global health is increasingly challenged by the growing prevalence of obesity and its associated complications. Quercetin, one of the most important dietary flavonoids, is being explored as an effective therapy for obesity with its mechanism remains understudied. Here in this study, it is demonstrated that quercetin intervention significantly reverses obesity-related phenotypes through reshaping the overall structure of microbiota, especially boosting colonization of the beneficial gut commensal Akkermansia muciniphila (A. muciniphila). Enrichment of A. muciniphila leads to generate more indole-3-lactic acid (ILA) to upregulate the expression of 12α-hydroxylase (CYP8B1) via fat mass and obesity-associated protein (FTO)/ N6-methyladenosine (m6A)/YTHDF2 manner, thereby facilitating cholesterol converts to cholic acid (CA). CA in turn drastically suppresses lipid accumulation via activating the farnesoid X receptor (FXR) in adipose tissue. This work introduces a novel therapeutic target for addressing obesity and expands upon the current limited understanding of the mediator function of m6A modifications in microorganism-influenced bile acid (BA) metabolism.

Nmnat2 deficiency in the arcuate nucleus or paraventricular nucleus induces Sarm1-independent neuron loss and liraglutide-reversible obesity

Nicotinamide mononucleotide adenylyltransferase 2 (Nmnat2) plays an important role in maintaining axon integrity, and the arcuate nucleus (ARC), and paraventricular nucleus (PVN) are crucial nuclei in the control of energy balance. However, the effect of Nmnat2 deficiency in ARC and PVN is still unclear. Nmnat2 loxP/loxP or Nmnat2 loxP/loxP , Sarm1 -/- mice were bilaterally injected with AAV-CMV-GFP-Cre once into the ARC, PVN, or lateral parabrachial nucleus (LPBN) to obtain Nmnat2 ARC-/- , Nmnat2 PVN-/- , Nmnat2 LPBN-/- , Nmnat2 ARC-/- , SKO, Nmnat2 PVN-/- , SKO, or Nmnat2 LPBN-/- , SKO mice. Syn1-Cre mice were bilaterally injected with AAV-EF1a-flex-taCasp3-TEVp once into the ARC or PVN to specifically induce neuron loss. Metabolic changes were measured in the mice intraperitoneally injected with or without liraglutide, a glucagon-like peptide-1 (GLP-1) analog. Neuron loss and neuron activation were monitored by immunofluorescence. Deletion of Nmnat2 in ARC or PVN of mice leads to neuron loss, increased food intake, and obesity in a Sarm1-independent manner. Intraperitoneal injection of liraglutide activates neurons in PVN and LPBN, and attenuates hyperphagia and obesity induced by Nmnat2 deletion or apoptosis of Syn1-positive neurons in ARC or PVN, but has no significant effect on neuron loss. Nmnat2 deficiency in LPBN leads to death within 2 weeks, which can be markedly rescued by Sarm1 deficiency. These data show that deletion of Nmnat2 in ARC or PVN in adult mice leads to Sarm1-independent neuron loss, and liraglutide-reversible hyperphagia and obesity. These findings also elucidate the integrated role of ARC or PVN for downregulating food intake, the requirement of LPBN for survival, and the ARC- or PVN-independent effect of GLP-1 on food intake.

Association of dietary water intake with body composition and the potential mechanism based on urinary metabolic signatures in Chinese elderly individuals aged 75 years and above

With the rising global aging rate, elderly nutrition and health issues are major concerns. Current research focuses on nutrients such as protein and vitamins, while there are limited studies on water intake in the elderly. The aim of this study was to assess whether Chinese people aged over 75 years are meeting the recommended adequate intake (AI) for total water intake and its relationship with body composition. This was done by exploring potential mechanisms through the analysis of urinary metabolites. Water intake and dietary status were collected from 456 community seniors aged over 75 years using a 24-hour water intake and dietary record form. Body composition was determined by bioelectrical impedance analysis (BIA). We found that 16.01% of community seniors reached the AI. The protein, fat-free mass (FFM) and skeletal muscle mass (SMM) levels were all increased in the AI group compared to the Collapse

Key Words Collapse

MESH Headings

• Humans
• Aged
• Body Composition
• Male
• Female
• Aged, 80 and over
• China
• Drinking
• Diet
• East Asian People

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Grants Collapse

Affiliation(s)

Sai Yao Institute of Nutrition and Health, School of Public Health, Qingdao University, Qingdao, Shandong, 266000, China.
Tianlin Gao Institute of Nutrition and Health, School of Public Health, Qingdao University, Qingdao, Shandong, 266000, China.
Yajun Liu Institute of Nutrition and Health, School of Public Health, Qingdao University, Qingdao, Shandong, 266000, China.
Ying Zhou Institute of Nutrition and Health, School of Public Health, Qingdao University, Qingdao, Shandong, 266000, China.
Zhixuan Zhao Institute of Nutrition and Health, School of Public Health, Qingdao University, Qingdao, Shandong, 266000, China.
Yinkun Wang Institute of Nutrition and Health, School of Public Health, Qingdao University, Qingdao, Shandong, 266000, China.
Xincen Wang Institute of Nutrition and Health, School of Public Health, Qingdao University, Qingdao, Shandong, 266000, China.
Aiguo Ma Institute of Nutrition and Health, School of Public Health, Qingdao University, Qingdao, Shandong, 266000, China.
Feng Zhong Institute of Nutrition and Health, School of Public Health, Qingdao University, Qingdao, Shandong, 266000, China.

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Collaborators Collapse

Neurotensin-neurotensin receptor 2 signaling in adipocytes suppresses food intake through regulating ceramide metabolism

Neurotensin (NTS) is a secretory peptide produced by lymphatic endothelial cells. Our previous study revealed that NTS suppressed the activity of brown adipose tissue via interactions with NTSR2. In the current study, we found that the depletion of Ntsr2 in white adipocytes upregulated food intake, while the local treatment of NTS suppressed food intake. Our mechanistic study revealed that suppression of NTS-NTSR2 signaling enhanced the phosphorylation of ceramide synthetase 2, increased the abundance of its products ceramides C20-C24, and downregulated the production of GDF15 in white adipose tissues, which was responsible for the elevation of food intake. We discovered a potential causal and positive correlation between serum C20-C24 ceramide levels and human food intake in four populations with different ages and ethnic backgrounds. Together, our study shows that NTS-NTSR2 signaling in white adipocytes can regulate food intake via its direct control of lipid metabolism and production of GDF15. The ceramides C20-C24 are key factors regulating food intake in mammals.

High protein diet increases the risk of allergic sensitization but not asthma in mice through modulation of the cytokine milieu toward Th2 bias

Introduction

The role of different nutrients in allergic sensitization is not clear. In this study we aimed to determine the effect of high protein (HP) diet on allergic sensitization, cytokine profile, and asthma in mice.

Methods

Seven- to eight-week old female BALB/c mice were fed either normal (ND) or HP diet and were sensitized with ovalbumin intraperitoneally followed by intranasal challenge. Allergic sensitization was tested by measuring anti-ovalbumin (OVA) IgE, IgG1, and IgG2a antibodies. Cytokine levels were tested by multiplex ELISA in splenocyte supernatants after stimulation. Airway inflammation was tested by measuring total and differential cell counts in bronchoalveolar lavage fluid and by measuring bronchial mucus production, goblet cell hyperplasia and perivascular and peribronchial inflammation severity scores by histologic examination.

Results

Mice fed HP diet had a significant increase in weight and higher levels of OVA-specific IgE and IgG1 antibodies compared to the ND group (P-values 0.002, 0.007 and <0.001, respectively). In addition, they showed a selective Th2 bias in cultured splenocyte supernatants compared to the ND group as demonstrated by higher IL-4 and IL-6 levels (P-values <0.001 and 0.011, respectively) and higher ratios of Th2 to Th1 cytokines. However, the level of airway inflammation was comparable between both groups.

Conclusions

HP diet increases the risk of allergic sensitization though increase in Th2 cytokines. Efforts should be made to define the upper limit of protein in the diet that does not predispose to allergic sensitization. The effect of diet on health should remain a focus of research for the establishment of optimal health and resilience.

Konjac Glucomannan and Its Degradation Products Inhibit Intestinal Lipid Absorption by Regulating Gut Microbiota and the Production of Short-Chain Fatty Acids

The effect of konjac glucomannan (KGM) on lipid absorption is related to the viscosity effect and hepatic lipid synthesis. However, the molecular mechanism of regulation of intestinal lipid absorption by KGM and its correlation with gut microbiota have not been studied. This study explored the effects of KGM and degradation products of KGM (DKGM) on intestinal lipid absorption and output in obese mice and their potential mechanisms. The results showed that KGM significantly reduces blood lipids and intestinal lipid accumulation compared to DKGM in obese mice. Moreover, KGM and DKGM downregulated intestinal HDAC3 and NFLI3 expression to suppress CD36, SREBP1, FABP1, and PPARα expression. Notably, KGM more effectively inhibited fatty acid uptake in extraintestinal tissues than DKGM. Importantly, KGM more effectively enhanced the intestinal barrier, altered microbe abundance associated with lipid absorption, and promoted SCFA production than DKGM. Correlation analysis found that KGM and DKGM inhibited intestinal lipid absorption, which were positively correlated with the abundance of Lactobacillus, Desulfovibrio, Allobaculum etc. In conclusion, KGM more effectively inhibits intestinal lipid absorption and output in high-fat diet mice than DKGM, which is related to viscosity, intestinal HDAC3 activity, and differential remodeling of the microbiome. These findings provide insights into how microbe-dietary fiber interactions regulate the host energy balance.

High-concentrate diet decreases lamb fatty acid contents by regulating bile acid composition

Feeding sheep with high-concentrate diet (HCD) to shorten production cycle is a well-developed feeding strategy to increase lamb production. Here, metabolomics were performed to explore the mechanism that HCD changes lamb nutrition composition. Differential metabolites were enriched in primary bile acid biosynthesis. Significantly higher content of bile acids including taurodeoxycholic acid sodium salt (TDCA), taurochenodeoxycholic acid sodium salt (TCDCA) and taurocholic acid (TCA) was observed in lamb of HCD, while the content of lithocholic acid (LCA), cholic acid (CA), chenodeoxycholic acid (CDCA) and Chenodeoxycholic acid-3-beta-D-glucuronide (CDCA-3Gln) were higher in the controls. Furthermore, a significantly decreased content of fatty acids was observed in lamb of HCD group. Finally, primary skeletal cells treated with CA or TCA showed a significant decrease in contents of fatty acids, while TCA showed a stronger effect in decreasing fatty acid contents. Collectively, we suggest that HCD decreases lamb fatty acid contents by regulating bile acid composition.

Branched-chain amino acids alleviate NAFLD via inhibiting de novo lipogenesis and activating fatty acid β-oxidation in laying hens

The adverse metabolic impacts of branched-chain amino acids (BCAA) have been elucidated are mediated by isoleucine and valine. Dietary restriction of isoleucine promotes metabolic health and increases lifespan. However, a high protein diet enriched in BCAA is presently the most useful therapeutic strategy for nonalcoholic fatty liver disease (NAFLD), yet, its underlying mechanism remains largely unknown. Fatty liver hemorrhagic syndrome (FLHS), a specialized laying hen NAFLD model, can spontaneously develop fatty liver and hepatic steatosis under a high-energy and high-protein dietary background that the pathogenesis of FLHS is similar to human NAFLD. The mechanism underlying dietary BCAA control of NAFLD development in laying hens remains unclear. Herein, we demonstrate that dietary supplementation with 67 % High BCAA has unique mitigative impacts on NAFLD in laying hens. A High BCAA diet alleviates NAFLD, by inhibiting the tryptophan-ILA-AHR axis and MAPK9-mediated de novo lipogenesis (DNL), promoting ketogenesis and energy metabolism, and activating PPAR-RXR and pexophagy to promote fatty acid β-oxidation. Furthermore, we uncover that High BCAA strongly activates ubiquitin-proteasome autophagy via downregulating UFMylation to trigger MAPK9-mediated DNL, fatty acid elongation and lipid droplet formation-related proteins ubiquitination degradation, activating PPAR-RXR and pexophagy mediated fatty acid β-oxidation and lipolysis. Together, our data highlight moderating intake of high BCAA by inhibiting the AHR/MAPK9 are promising new strategies in NAFLD and FLHS treatment.

Integrated multi-omics profiling highlights the diet-gut-brain axis in low-calorie diets promoted novelty-seeking behavior

The foods that we eat are closely linked to the development and function of neurophysiology, affecting mood, cognition, and mental health. Yet, it is not known whether and how dietary patterns affect brain function and mood. Here, we explored the impact of various diets on the behavior of mice. Low-calorie (LC) diet-fed mice exhibited increased novel exploratory behaviors, including novelty to new foods, objects, and environments. The host transcriptome sequencing showed an increase of Areg in the cerebral cortex of mice fed with LC, and IMPC showed that Areg knock-out mice exhibited significantly decreased exploration of novel environments. According to the metagenomic sequencing results, a significant increase in the levels of s_Schaedlerella and s_1XD8-76 was observed after LC feeding. Integrated analysis of microbiota metabolites and host transcriptomics suggested that 68 differential metabolites in LC-fed mice were associated with upregulation of Areg expression. This study demonstrates the powerful impact of LC feeding on the restoration of gut microbiota and the improvement of novelty-seeking behavior. In addition, this study supports the idea that microbiota-associated metabolites can modulate host gene transcription, which provides a link between dietary patterns and their impact on the emotional and cognitive centers of the brain.

Yoyo Dieting, Post-Obesity Weight Loss, and Their Relationship with Gut Health

Excessive body weight is associated with many chronic metabolic diseases and weight loss, so far, remains the gold standard treatment. However, despite tremendous efforts exploring optimal treatments for obesity, many individuals find losing weight and maintaining a healthy body weight difficult. Weight loss is often not sustainable resulting in weight regain and subsequent efforts to lose weight. This cyclic pattern of weight loss and regain is termed "yoyo dieting" and predisposes individuals to obesity and metabolic comorbidities. How yoyo dieting might worsen obesity complications during the weight recurrence phase remains unclear. In particular, there is limited data on the role of the gut microbiome in yoyo dieting. Gut health distress, especially gut inflammation and microbiome perturbation, is strongly associated with metabolic dysfunction and disturbance of energy homeostasis in obesity. In this review, we summarise current evidence of the crosstalk between the gastrointestinal system and energy balance, and the effects of yoyo dieting on gut inflammation and gut microbiota reshaping. Finally, we focus on the potential effects of post-dieting weight loss in improving gut health and identify current knowledge gaps within the field, including gut-derived peptide hormones and their potential suitability as targets to combat weight regain, and how yoyo dieting and associated changes in the microbiome affect the gut barrier and the enteric nervous system, which largely remain to be determined.

Whole-genome analysis, evaluation and regulation of in vitro and in vivo GABA production from Levilactobacillus brevis YSJ3

Gamma-aminobutyric acid (GABA) produced by lactic acid bacteria (LAB) is safe and has several health benefits. Levilactobacillus brevis YSJ3 was selected from 110 LAB. It exhibited the highest in vitro GABA production level of 970.10 μg/mL. Whole-genome analysis revealed that L. brevis YSJ3 contained gadR, gadC, gadB and gadA. Furthermore, the Luedeking-Piret model was fitted, which indicated that GABA production was divided into three stages. The gadR 0079, gadC 0080, and gadB 0081 were confirmed to promote GABA synthesis. Moreover, 55 metabolites, particularly those involved in arginine metabolism, were significantly different at 6 and 20 h of cultivation. Notably, L. brevis YSJ3 significantly improved sleep in mice and increased GABA levels in the mice's gut compared with the control group. This suggests that the oral administration of L. brevis YSJ3 improves sleep quality, probably by increasing intestinal GABA levels. Overall, L. brevis YSJ3 was confirmed as a GABA-producing strain in vitro and in vivo, making it a promising probiotic candidate for its application in food and medicine.

Research advances in the therapy of metabolic syndrome

Metabolic syndrome refers to the pathological state of metabolic disorder of protein, fat, carbohydrate, and other substances in the human body. It is a syndrome composed of a group of complex metabolic disorders, whose pathogenesis includes multiple genetic and acquired entities falling under the category of insulin resistance and chronic low-grade inflammationand. It is a risk factor for increased prevalence and mortality from diabetes and cardiovascular disease. Cardiovascular diseases are the predominant cause of morbidity and mortality globally, thus it is imperative to investigate the impact of metabolic syndrome on alleviating this substantial disease burden. Despite the increasing number of scientists dedicating themselves to researching metabolic syndrome in recent decades, numerous aspects of this condition remain incompletely understood, leaving many questions unanswered. In this review, we present an epidemiological analysis of MetS, explore both traditional and novel pathogenesis, examine the pathophysiological repercussions of metabolic syndrome, summarize research advances, and elucidate the mechanisms underlying corresponding treatment approaches.

Cellular Senescence and Extracellular Vesicles in the Pathogenesis and Treatment of Obesity-A Narrative Review

This narrative review explores the pathophysiology of obesity, cellular senescence, and exosome release. When exposed to excessive nutrients, adipocytes develop mitochondrial dysfunction and generate reactive oxygen species with DNA damage. This triggers adipocyte hypertrophy and hypoxia, inhibition of adiponectin secretion and adipogenesis, increased endoplasmic reticulum stress and maladaptive unfolded protein response, metaflammation, and polarization of macrophages. Such feed-forward cycles are not resolved by antioxidant systems, heat shock response pathways, or DNA repair mechanisms, resulting in transmissible cellular senescence via autocrine, paracrine, and endocrine signaling. Senescence can thus affect preadipocytes, mature adipocytes, tissue macrophages and lymphocytes, hepatocytes, vascular endothelium, pancreatic β cells, myocytes, hypothalamic nuclei, and renal podocytes. The senescence-associated secretory phenotype is closely related to visceral adipose tissue expansion and metaflammation; inhibition of SIRT-1, adiponectin, and autophagy; and increased release of exosomes, exosomal micro-RNAs, pro-inflammatory adipokines, and saturated free fatty acids. The resulting hypernefemia, insulin resistance, and diminished fatty acid β-oxidation lead to lipotoxicity and progressive obesity, metabolic syndrome, and physical and cognitive functional decline. Weight cycling is related to continuing immunosenescence and exposure to palmitate. Cellular senescence, exosome release, and the transmissible senescence-associated secretory phenotype contribute to obesity and metabolic syndrome. Targeted therapies have interrelated and synergistic effects on cellular senescence, obesity, and premature aging.

Effects of different energy levels in low-protein diet on liver lipid metabolism in the late-phase laying hens through the gut-liver axis

BACKGROUND

The energy/protein imbalance in a low-protein diet induces lipid metabolism disorders in late-phase laying hens. Reducing energy levels in the low-protein diet to adjust the energy-to-protein ratio may improve fat deposition, but this also decreases the laying performance of hens. This study investigated the mechanism by which different energy levels in the low-protein diet influences liver lipid metabolism in late-phase laying hens through the enterohepatic axis to guide feed optimization and nutrition strategies. A total of 288 laying hens were randomly allocated to the normal-energy and normal-protein diet group (positive control: CK) or 1 of 3 groups: low-energy and low-protein diet (LL), normal-energy and low-protein diet (NL), and high-energy and low-protein diet (HL) groups. The energy-to-protein ratios of the CK, LL, NL, and HL diets were 0.67, 0.74, 0.77, and 0.80, respectively.

RESULTS

Compared with the CK group, egg quality deteriorated with increasing energy intake in late-phase laying hens fed low-protein diet. Hens fed LL, NL, and HL diets had significantly higher triglyceride, total cholesterol, acetyl-CoA carboxylase, and fatty acid synthase levels, but significantly lower hepatic lipase levels compared with the CK group. Liver transcriptome sequencing revealed that genes involved in fatty acid beta-oxidation (ACOX1, HADHA, EHHADH, and ACAA1) were downregulated, whereas genes related to fatty acid synthesis (SCD, FASN, and ACACA) were upregulated in LL group compared with the CK group. Comparison of the cecal microbiome showed that in hens fed an LL diet, Lactobacillus and Desulfovibrio were enriched, whereas riboflavin metabolism was suppressed. Cecal metabolites that were most significantly affected by the LL diet included several vitamins, such as riboflavin (vitamin B2), pantethine (vitamin B5 derivative), pyridoxine (vitamin B6), and 4-pyridoxic acid.

CONCLUSION

A lipid metabolism disorder due to deficiencies of vitamin B2 and pantethine originating from the metabolism of the cecal microbiome may be the underlying reason for fat accumulation in the liver of late-phase laying hens fed an LL diet. Based on the present study, we propose that targeting vitamin B2 and pantethine (vitamin B5 derivative) might be an effective strategy for improving lipid metabolism in late-phase laying hens fed a low-protein diet.

Ketogenic diet-induced bile acids protect against obesity through reduced calorie absorption

The low-carbohydrate ketogenic diet (KD) has long been practiced for weight loss, but the underlying mechanisms remain elusive. Gut microbiota and metabolites have been suggested to mediate the metabolic changes caused by KD consumption, although the particular gut microbes or metabolites involved are unclear. Here, we show that KD consumption enhances serum levels of taurodeoxycholic acid (TDCA) and tauroursodeoxycholic acid (TUDCA) in mice to decrease body weight and fasting glucose levels. Mechanistically, KD feeding decreases the abundance of a bile salt hydrolase (BSH)-coding gut bacterium, Lactobacillus murinus ASF361. The reduction of L. murinus ASF361 or inhibition of BSH activity increases the circulating levels of TDCA and TUDCA, thereby reducing energy absorption by inhibiting intestinal carbonic anhydrase 1 expression, which leads to weight loss. TDCA and TUDCA treatments have been found to protect against obesity and its complications in multiple mouse models. Additionally, the associations among the abovementioned bile acids, microbial BSH and metabolic traits were consistently observed both in an observational study of healthy human participants (n = 416) and in a low-carbohydrate KD interventional study of participants who were either overweight or with obesity (n = 25). In summary, we uncover a unique host-gut microbiota metabolic interaction mechanism for KD consumption to decrease body weight and fasting glucose levels. Our findings support TDCA and TUDCA as two promising drug candidates for obesity and its complications in addition to a KD.

Gut microbiome remodeling and metabolomic profile improves in response to protein pacing with intermittent fasting versus continuous caloric restriction

The gut microbiome (GM) modulates body weight/composition and gastrointestinal functioning; therefore, approaches targeting resident gut microbes have attracted considerable interest. Intermittent fasting (IF) and protein pacing (P) regimens are effective in facilitating weight loss (WL) and enhancing body composition. However, the interrelationships between IF- and P-induced WL and the GM are unknown. The current randomized controlled study describes distinct fecal microbial and plasma metabolomic signatures between combined IF-P (n = 21) versus a heart-healthy, calorie-restricted (CR, n = 20) diet matched for overall energy intake in free-living human participants (women = 27; men = 14) with overweight/obesity for 8 weeks. Gut symptomatology improves and abundance of Christensenellaceae microbes and circulating cytokines and amino acid metabolites favoring fat oxidation increase with IF-P (p < 0.05), whereas metabolites associated with a longevity-related metabolic pathway increase with CR (p < 0.05). Differences indicate GM and metabolomic factors play a role in WL maintenance and body composition. This novel work provides insight into the GM and metabolomic profile of participants following an IF-P or CR diet and highlights important differences in microbial assembly associated with WL and body composition responsiveness. These data may inform future GM-focused precision nutrition recommendations using larger sample sizes of longer duration. Trial registration, March 6, 2020 (ClinicalTrials.gov as NCT04327141), based on a previous randomized intervention trial.

Theabrownin from Qingzhuan tea prevents high-fat diet-induced MASLD via regulating intestinal microbiota

The aim of this study was to investigate whether the therapeutic effect of theabrownin extracted from Qingzhuan tea (QTB) on metabolic dysfunction-associated steatosis liver disease (MASLD) is related to the regulation of intestinal microbiota and its metabolite short-chain fatty acids (SCFAs). Mice were divided into four groups and received normal diet (ND), high-fat diet (HFD) and HFD+QTB (180, 360 mg/kg) for 8 weeks. The results showed that QTB significantly reduced the body weight of HFD mice, ameliorated liver lipid and dyslipidemia, and increased the level of intestinal SCFAs in HFD mice. The results of 16 S rRNA showed that the relative abundance of Bacteroides, Blautia and Lachnoclostridium and their main metabolites acetate and propionate were significantly increased after QTB intervention. The relative abundance of Colidextribacter, Faecalibaculum and Lactobacillus was significantly reduced. QTB can also significantly up-regulate the expression of ATGL, PPARα, FFAR2 and FFAR3, and inhibit the expression of LXRα, SREBP-1c, FAS and HMGCR genes. This makes it possible to act as a prebiotic to prevent MASLD.

Investigation the mechanism of iron overload-induced colonic inflammation following ferric citrate exposure

Iron overload occurs due to excessive iron intake compared to the body's demand, leading to iron deposition and impairment of multiple organ functions. Our previous study demonstrated that chronic oral administration of ferric citrate (FC) caused colonic inflammatory injury. However, the precise mechanism underlying this inflammatory response remains unclear. The current study aims to investigate the mechanism by which iron overload induced by FC exposure leads to colonic inflammation. To accomplish this, mice were orally exposed to three different concentrations of FC (71 mg/kg/bw (L), 143 mg/kg/bw (M) and 286 mg/kg/bw (H)) for continuous 16 weeks, with the control group receiving ultrapure water (C). Exposure to FC caused disturbances in the excretory system, altered colonic flora alpha diversity, and enriched pathogenic bacteria, such as Mucispirillum, Helicobacter, Desulfovibrio, and Shigella. These changes led to structural disorders of the colonic flora and an inflammatory response phenotype characterized by inflammatory cells infiltration, atrophy of intestinal glands, and irregular thickening of the intestinal wall. Mechanistic studies revealed that FC-exposure activated the NF-κB signaling pathway by up-regulating TLR4, MyD88, and NF-κB mRNA levels and protein expression. This activation resulted in increased production of pro-inflammatory cytokines, further contributing to the colonic inflammation. Additionally, in vitro experiments in SW480 cells confirmed the activation of NF-κB signaling pathway by FC exposure, consistent with the in vivo findings. The significance of this study lies in its elucidation of the mechanism by which iron overload caused by FC exposure leads to colonic inflammation. By identifying the role of pathogenic bacteria and the NF-κB signaling pathway, this study could potentially offer a crucial theoretical foundation for the research on iron overload, as well as provide valuable insights for clinical iron supplementation.

Potential of longan (Dimocarpus longan Lour.) in functional food: A review of molecular mechanism-directing health benefit properties

Longan (Dimocarpus longan Lour.) has received widespread attention worldwide as a therapeutic food with nutritional, economic, and medicinal value. Its fruit, seed, pericarp, and flower becoming dietary tools for health maintenance when it comes to targeting chronic diseases or sub-health conditions. In recent years, research focusing on longan and human health has intensified, and the high-value products of the whole fruit, including polyphenols, polysaccharides, angiotensin-I-converting enzyme (ACE)-inhibiting peptides, gamma-aminobutyric acid (GABA), and Maillard reaction products etc., may have beneficial effects on human health by preventing the onset of chronic diseases and cancer, maintaining intestinal homeostasis and skin health. Here, we review and summarize the new available evidence on the bioactive role of phytochemicals in longan and explore the relationship between longan bioactive compounds and health benefits, with a focus on the molecular mechanisms of the health effects.

Diarrhea induced by insufficient fat absorption in weaned piglets: Causes and nutrition regulation

Fat is one of the three macronutrients and a significant energy source for piglets. It plays a positive role in maintaining intestinal health and improving production performance. During the weaning period, physiological, stress and diet-related factors influence the absorption of fat in piglets, leading to damage to the intestinal barrier, diarrhea and even death. Signaling pathways, such as fatty acid translocase (CD36), pregnane X receptor (PXR), and AMP-dependent protein kinase (AMPK), are responsible for regulating intestinal fat uptake and maintaining intestinal barrier function. Therefore, this review mainly elaborates on the reasons for diarrhea induced by insufficient fat absorption and related signaling pathways in weaned-piglets, with an emphasis on the intestinal fat absorption disorder. Moreover, we focus on introducing nutritional strategies that can promote intestinal fat absorption in piglets with insufficient fat absorption-related diarrhea, such as lipase, amino acids, and probiotics.

Diet Change Improves Obesity and Lipid Deposition in High-Fat Diet-Induced Mice

The number of obese people is increasing dramatically worldwide, and one of the major causes of obesity is excess energy due to high-fat diets. Several studies have shown that reducing food and energy intake represents a key intervention or treatment to combat overweight/obesity. Here, we conducted a 12-week energy-restricted dietary intervention for high-fat diet-induced obese mice (C57BL/6J) to investigate the effectiveness of diet change in improving obesity. The results revealed that the diet change from HFD to NFD significantly reduced weight gain and subcutaneous adipose tissue weight in high-fat diet-induced obese mice, providing scientific evidence for the effectiveness of diet change in improving body weight and fat deposition in obese individuals. Regarding the potential explanations for these observations, weight reduction may be attributed to the excessive enlargement of adipocytes in the white adipose tissue of obese mice that were inhibited. Diet change significantly promoted lipolysis in the adipose tissue (eWAT: Adrb3, Plin1, HSL, and CPTA1a; ingWAT: CPT1a) and liver (reduced content of nonesterified fatty acids), and reduced lipogenesis in ingWAT (Dgat2). Moreover, the proportion of proliferative stem cells in vWAT and sWAT changed dramatically with diet change. Overall, our study reveals the phenotypic, structural, and metabolic diversity of multiple tissues (vWAT and sWAT) in response to diet change and identifies a role for adipocyte stem cells in the tissue specificity of diet change.

Osteocalcin has a muscle-protective effect during weight loss in men without metabolic syndrome: a multicenter, prospective, observational study

Objective

Weight reduction often accompanies muscle loss. Existing studies highlight the involvement of osteocalcin (OC) in energy metabolism and its potential to prevent age-related muscle loss. Nevertheless, these studies predominantly involve individuals with hyperglycemia, yielding conflicting research outcomes. This study investigated the protective role of OC against muscle loss during weight reduction in individuals without metabolic syndrome (MetS).

Measures

We enrolled 130 overweight or obese individuals without MetS in a 4-month high-protein, energy-restricted dietary weight management program conducted at two clinic centers. Body composition and laboratory tests were assessed both before and after weight loss. Correlation and regression analysis were made between the changes in metabolic indicators and muscle mass during weight loss.

Results

Following weight loss, there was a decrease in body mass index (BMI), percentage of body fat (PBF), visceral fat area (VFA), fasting insulin (FINS), homeostasis model assessment insulin resistance (HOMA-IR), glycated haemoglobin (HbA1c), and lipid profile, and increase in the percentage of skeletal muscle (PSM) and vitamin D. There was no change in osteocalcin (OC) during the intervention. Correlation analysis of the relative changes in all metabolic indicators revealed a positive correlation between OC and PSM (r=0.383, p=0.002). Multiple linear regression analysis found that OC has a significant protective effect on muscles during weight loss in males after adjusting for confounding factors (β=0.089, p=0.017).

Conclusion

High-protein, energy-restricted diets demonstrate efficacy in enhancing metabolic indicators within the weight-loss population. Furthermore, OC exhibits a protective effect on muscle mass during weight reduction in individuals without MetS, with this effect being particularly evident in males.

Evidence for the contribution of the gut microbiome to obesity and its reversal

Obesity has become a worldwide pandemic affecting more than 650 million people and is associated with a high burden of morbidity. Alongside traditional risk factors for obesity, the gut microbiome has been identified as a potential factor in weight regulation. Although rodent studies suggest a link between the gut microbiome and body weight, human evidence for causality remains scarce. In this Review, we postulate that existing evidence remains to establish a contribution of the gut microbiome to the development of obesity in humans but that modified probiotic strains and supraphysiological dosages of microbial metabolites may be beneficial in combatting obesity.

Effects of Diet Macronutrient Composition on Weight Loss during Caloric Restriction and Subsequent Weight Regain during Refeeding in Aging Mice

Caloric restriction (CR) induces weight loss, but is associated with rapid weight regain upon return to ad libitum feeding. Our aim was to investigate effects of the macronutrient composition of the diet on weight loss and regain in elderly mice. Males, 18 months old, of the C57BL/6J strain were subjected to 4-week 30% CR followed by 4 weeks of ad libitum refeeding on either high-carb (HC), high-fat (HF) or high-protein (HP) diets (n = 22 each). Mice (n = 11) fed a chow diet ad libitum served as a control group (CON). Body mass and food intake were monitored daily. Twenty-four-hour indirect calorimetry was used to assess energy expenditure and substrate oxidation. Muscle and fat mass were evaluated with dissection of the tissues. Serum leptin and ghrelin levels were also measured. CR-induced weight loss did not differ between the diets. Weight regain was particularly fast for HF as mice overshot their initial weight by 12.8 ± 5.7% after 4-week refeeding when HC and HP mice reached the weight of the CON group. Weight regain strongly correlated with energy intake across the groups. The respiratory exchange ratio was lower in HF mice (0.81 ± 0.03) compared to HC (0.94 ± 0.06, p < 0.001), HP (0.89 ± 0.04, p < 0.001) and CON mice (0.91 ± 0.06, p < 0.01) during the refeeding. Serum leptin levels were higher in HF mice (1.03 ± 0.50 ng/mL) compared to HC (0.46 ± 0.14, p < 0.001), HP (0.63 ± 0.28, p < 0.05) or CON mice (0.41 ± 0.14, p < 0.001). Thus, CR induces similar weight loss in aging mice irrespective of the diet's macronutrient composition. An HF diet leads to excessive energy intake and pronounced gain in body fat in spite of increased fat oxidation and serum leptin during the refeeding after CR.

Bone marrow immune cells stop weight regain

Weight regain is a major challenge in the long-term management of obesity; however, the underlying mechanisms remain unclear. Zhou et al. found that bone-marrow-derived CD7+ monocytes respond to fluctuating nutritional stress and suppress weight regain by promoting beige fat thermogenesis.

Bone marrow immune cells respond to fluctuating nutritional stress to constrain weight regain

Weight regain after weight loss is a major challenge in the treatment of obesity. Immune cells adapt to fluctuating nutritional stress, but their roles in regulating weight regain remain unclear. Here, we identify a stem cell-like CD7+ monocyte subpopulation accumulating in the bone marrow (BM) of mice and humans that experienced dieting-induced weight loss. Adoptive transfer of CD7+ monocytes suppresses weight regain, whereas inducible depletion of CD7+ monocytes accelerates it. These cells, accumulating metabolic memories via epigenetic adaptations, preferentially migrate to the subcutaneous white adipose tissue (WAT), where they secrete fibrinogen-like protein 2 (FGL2) to activate the protein kinase A (PKA) signaling pathway and facilitate beige fat thermogenesis. Nevertheless, CD7+ monocytes gradually enter a quiescent state after weight loss, accompanied by increased susceptibility to weight regain. Notably, administration of FMS-like tyrosine kinase 3 ligand (FLT3L) remarkably rejuvenates CD7+ monocytes, thus ameliorating rapid weight regain. Together, our findings identify a unique bone marrow-derived metabolic-memory immune cell population that could be targeted to combat obesity.

A short-term high-sugar diet is an aggravating factor in experimental allergic contact dermatitis

Allergic contact dermatitis (ACD) is an inflammatory skin reaction whose incidence has increased and has been associated with a dietary pattern rich in saturated fats and refined sugars. Considering the increased incidence of ACD and the lack of research about the influence of a short-term high-sugar diet on dermatitis, our aim is to improve understanding of the influence of a high-sugar diet on ACD. We introduced a diet rich in sugar fifteen days before inducing contact dermatitis with oxazolone, in mice, and maintained it until the end of the experiment, which lasted three weeks in total. The dermatitis model increased cholesterol and triglycerides in the liver, and the combination of diet and dermatitis increased weight and worsened liver cholesterol measurements. Furthermore, the high-sugar diet increased the production of IL-6, IFN-γ and TNF-α in the skin, which may be involved in the increase in epithelial skin thickness observed in experimental ACD.

Protein and amino acids in obesity: friends or foes?

PURPOSE OF REVIEW

Nutritional interventions using protein and amino acids in obesity are popular therapeutical strategies to limit obesity development. However, the effects of dietary protein intake and amino acid metabolic alterations involved in obesity pathophysiology have not been completely unravelled. Significant recent studies have brought to light new findings in these areas, which are the primary focus of this review.

RECENT FINDINGS

We describe the effects of protein intake on weight regain prevention, the influence on gut microbiota, the response to low-protein highly processed foods, and the contrasting impacts of a high-protein diet on adults and children. We also explore newly discovered correlations between amino acids, liver fat accumulation, and the dysregulation of the liver-pancreas axis due to alterations in amino acid levels in the context of obesity. Lastly, we consider branched-chain amino acids, along with glycine and tryptophan, as significant biomarkers during periods of positive or negative energy balance.

SUMMARY

Interventions using dietary protein in obesity may be useful, especially during energy restriction but also in sarcopenic obesity. Furthermore, metabolic profiles that encompass alterations in certain amino acids can provide valuable insights into the metabolic condition of patients with obesity, particularly in relation to insulin resistance and the risk of developing type 2 diabetes.

An early-life microbiota metabolite protects against obesity by regulating intestinal lipid metabolism

The mechanisms by which the early-life microbiota protects against environmental factors that promote childhood obesity remain largely unknown. Using a mouse model in which young mice are simultaneously exposed to antibiotics and a high-fat (HF) diet, we show that Lactobacillus species, predominant members of the small intestine (SI) microbiota, regulate intestinal epithelial cells (IECs) to limit diet-induced obesity during early life. A Lactobacillus-derived metabolite, phenyllactic acid (PLA), protects against metabolic dysfunction caused by early-life exposure to antibiotics and a HF diet by increasing the abundance of peroxisome proliferator-activated receptor γ (PPAR-γ) in SI IECs. Therefore, PLA is a microbiota-derived metabolite that activates protective pathways in the small intestinal epithelium to regulate intestinal lipid metabolism and prevent antibiotic-associated obesity during early life.

Metabolic inputs in the probiotic bacterium Lacticaseibacillus rhamnosus contribute to cell-wall remodeling and increased fitness

Lacticaseibacillus rhamnosus GG (LGG) is a Gram-positive beneficial bacterium that resides in the human intestinal tract and belongs to the family of lactic acid bacteria (LAB). This bacterium is a widely used probiotic and was suggested to provide numerous benefits for human health. However, as in most LAB strains, the molecular mechanisms that mediate the competitiveness of probiotics under different diets remain unknown. Fermentation is a fundamental process in LAB, allowing the oxidation of simple carbohydrates (e.g., glucose, mannose) for energy production under oxygen limitation, as in the human gut. Our results indicate that fermentation reshapes the metabolome, volatilome, and proteome architecture of LGG. Furthermore, fermentation alters cell envelope remodeling and peptidoglycan biosynthesis, which leads to altered cell wall thickness, aggregation properties, and cell wall composition. In addition, fermentable sugars induced the secretion of known and novel metabolites and proteins targeting the enteric pathogens Enterococcus faecalis and Salmonella enterica Serovar Typhimurium. Overall, our results link simple carbohydrates with cell wall remodeling, aggregation to host tissues, and biofilm formation in probiotic strains and connect them with the production of broad-spectrum antimicrobial effectors.

The Role of Diet and Gut Microbiota Interactions in Metabolic Homeostasis

Diet is a pivotal determinant in shaping the structure and function of resident microorganisms in the gut through different food components, nutritive proportion, and calories. The effects of diet on host metabolism and physiology can be mediated through the gut microbiota. Gut microbiota-derived metabolites have been shown to regulate glucose and lipid metabolism, energy consumption, and the immune system. On the other hand, emerging evidence indicates that baseline gut microbiota could predict the efficacy of diet intervention, highlighting gut microbiota can be harnessed as a biomarker in personalized nutrition. In this review, the alterations of gut microbiota in different dietary components and dietary patterns, and the potential mechanisms in the diet-microbiota crosstalk are summarized to understand the interactions of diet and gut microbiota on the impact of metabolic homeostasis.

A Study on the Amelioration of Circadian Rhythm Disorders in Fat Mice Using High-Protein Diets

This innovative study investigates the effects of high-protein diets (milk protein) on the circadian rhythm of hepatic lipid metabolism. We aimed to understand how high-protein interventions regulate biological clock genes, maintain lipid metabolism balance, and affect the circadian rhythm of antioxidant levels in vivo. We divided 120 SPF-class C57BL/6J mice into the control, high-fat/low-protein (HF-LP), and high-fat/high-protein (HF-HP) groups. Mice were sacrificed during active (2 a.m. and 8 a.m.) and rest periods (2 p.m. and 8 p.m.). In the HF-LP group, hepatic lipid anabolic enzymes were consistently expressed at high levels, while key lipolytic enzymes slowly increased after feeding with no significant diurnal differences. This led to an abnormal elevation in blood lipid levels, a slow increase in and low levels of superoxide dismutase, and a rapid increase in malondialdehyde levels, deviating from the diurnal trend observed in the control group. However, high-protein interventions in the HF-HP group restored lipid synthase activity and the expression of key catabolic enzymes, exhibiting a precise circadian rhythm. It also improved the lipid-metabolism rhythm, which was disrupted by the high-fat diet. Overall, high-protein interventions restored the expression of key enzymes involved in lipid metabolism, improving the lipid-metabolism rhythm, which was disrupted by the high-fat diet.