Intermittent Fasting Promotes White Adipose Browning and Decreases Obesity by Shaping the Gut Microbiota

Polystyrene microplastics impair brown and beige adipocyte function via the gut microbiota-adipose tissue crosstalk in high-fat diet mice

BACKGROUND

Microplastics (MPs) are pervasive in the environment and food. The potential health hazards of this emerging pollutant have raised significant concerns in recent years. However, the underlying mechanism by which MPs have any impact on brown and beige adipocytes in the context of obesity is yet to be investigated.

METHODS

The C57BL/6 J mice were randomly assigned to the HFD and HFD+MPs group for 12 weeks of exposure to explore the differences in brown and beige adipocyte function. The gut microbiota analysis, fecal microbiota transplantation and metabolomic profiling were carried out to further determine its potential mechanism.

RESULTS

The present work demonstrated that high-fat diet mice accumulate lipids and have reduced energy expenditure after three months of oral administration of MPs. In addition to escalating intestinal dysbiosis, exposing HFD mice to MPs induces thermogenic dysfunction in inguinal white adipose tissue and brown adipose tissue. Following the fecal microbiota transplantation, the accumulation of lipids and dysfunction in energy expenditure within the microbiota of recipient mice further elucidated the inhibitory effect of MPs.

CONCLUSIONS

Our results suggest that MPs induced the thermogenic dysfunction of BAT and iWAT by affecting gut microbiota composition. The present study highlights the mechanisms by which MPs produce thermogenic dysfunction in BAT and iWAT and disruption in the gastrointestinal microbiota.

Diet, gut microbiota, and health: a review

The relationship between diet and human physical and mental health is highly interconnected and has been significantly correlated with the occurrence of various diseases, including neurological disorders, cancer, and chronic inflammatory diseases. Moreover, diet has been demonstrated to play a pivotal role in governing gut microbiota composition, making it one of the most influential factors. The diet is crucial in connecting humans and their gut microorganisms. The nutrients ingested supply energy to the body and serve as substrates for the metabolic processes of the gut microorganisms. Consequently, the gut flora and their metabolites reciprocally impact the host's metabolism, thereby influencing the physiological state of the human body. Extensive investigations on human and mouse models have revealed that diet potentially underlies various effects on human health and disease.

Graphical abstract

Intermittent fasting and metabolic dysfunction-associated steatotic liver disease: the potential role of the gut-liver axis

Metabolic dysfunction-associated steatotic liver disease (MASLD) is a growing public health concern linked to the increasing prevalence of metabolic syndrome, including obesity and type 2 diabetes (T2D). MASLD remains a significant clinical challenge due to the absence of effective therapeutic interventions. Intermittent fasting (IF) has emerged as a promising non-pharmacological strategy for managing MASLD. Although the exact mechanisms underpinning the possible beneficial effects of IF on MASLD are not yet fully elucidated, the gut microbiota and its metabolic byproducts are increasingly recognized as potential mediators of these effects. The gut-liver axis may act as an important conduit through which IF exerts its beneficial influence on hepatic function. This review comprehensively examines the impact of various IF protocols on gut microbiota composition, investigating the resultant alterations in microbial diversity and metabolomic profiles, and their potential implications for liver health and the improvement of MASLD.

Structural characterization and alleviative effects of novel polysaccharides from Artemisia sphaerocephala Krasch seed on obese mice by regulating gut microbiota

This study aimed to investigate the efficacy of polysaccharides from Artemisia sphaerocephala Krasch (ASK) seed in alleviating high fat diet (HFD) caused obesity. Here, three polysaccharide fractions (ASKP1, ASKP2 and ASKP3) were purified from ASK seed. Chemical characteristic analysis revealed that ASKP1 is a neutral heteropolysaccharide with the average molecular weight of 9.08 × 105 Da, while ASKP2 and ASKP3 are acidic heteropolysaccharides with the molecular weight of 9.39 × 105 and 8.41 × 105 Da, respectively. Animal experiment found that three ASKP fractions obviously relieved obesity and related metabolic disorders induced by HFD, while ASKP1 was more effective in reducing the blood glucose and serum LDL levels. 16S rDNA sequencing showed that ASKP fractions improved the gut microbiota imbalance of obese mice, and ASKP1 promoted the proliferation of beneficial bacterium Akkermansia more effectively than ASKP2 and ASKP3. Furthermore, ASKP fractions facilitated thermogenesis of brown adipose tissue (BAT) of obese mice, as evidenced by increased expression of thermogenic marker genes UCP1 in BAT, and the thermogenesis effect of ASKP1 was the most obvious. Taken together, our results show that ASKP1 is a novel prebiotic that may be used to treat obesity and its related abnormal metabolism.

16/8 intermittent fasting in mice protects from diet-induced obesity by increasing leptin sensitivity and postprandial thermogenesis

AIMS

To evaluate the molecular mechanisms involved in intermittent fasting 16/8 (16/8 IF), a widespread dietary practice adopted worldwide that consists of 16 h of fasting and 8 h of feeding.

METHODS

Obese mice were fasted daily from 6 am to 10 pm. Food intake, body weight, and energy expenditure were measured. Molecular mechanisms were investigated using ELISA, western blot, and qPCR of white and brown adipose tissues. Glucose homeostasis was also evaluated. Ucp1 knockout and ob/ob mice were utilized.

RESULTS

The 16/8 IF regimen improved glucose homeostasis and reduced body weight, food intake, and overall adiposity. Postprandial VO2, heat production, brown adipose tissue (BAT) temperature, and ketone bodies increased with 16/8 IF. Postprandial thermogenesis induced by 16/8 IF was abolished in mice after BAT denervation or Ucp1 deletion. Serum leptin levels were elevated, and most metabolic effects of 16/8 IF were absent in leptin-deficient ob/ob mice. Additionally, leptin sensitivity increased in mice exposed to 16/8 IF.

CONCLUSION

The 16/8 IF regimen can improve metabolism, with findings underscoring the role of enhanced leptin action in inhibiting food intake and promoting postprandial thermogenesis during 16/8 IF.

Bariatric surgery promotes recruitment of brown fat linked to alterations in the gut microbiota

OBJECTIVE

The mechanisms of bariatric surgery-induced weight loss and metabolic improvements are still incompletely understood and reach beyond malabsorption or calorie restriction. We sought to investigate the effect of bariatric surgery on brown adipose tissue (BAT) activity and a potential connection with changes in energy metabolism, the gut microbiota, and short-chain fatty acid (SCFA) composition.

METHODS

We included 32 subjects (25 females) with morbid obesity and analyzed their metabolic profile, gut microbiota composition, circulating SCFAs, energy expenditure, and cold-induced BAT activity using [18F]Fluorodeoxyglucose-positron emission tomography-computed tomography before and up to 1 year after bariatric surgery.

RESULTS

Twelve months after surgery, the percentage of individuals with active BAT had increased from 28% to 53%. The BAT-negative (BATneg) individuals who had an adverse metabolic profile at baseline compared with subjects with active BAT (BATpos) showed a greater metabolic benefit after surgery. While no changes in overall gut bacterial diversity were observed between BATpos and BATneg, the abundance of 3 specific bacterial families, including Akkermansiaceae, Pasteurellaceae, and Carnobacteriaceae, was distinctly regulated between BAT groups. The bacterial genera most strongly increased in BATpos vs BATneg subjects were all positively correlated with BAT volume and BAT activity. Finally, circulating concentrations of the SCFAs acetate, butyrate, and propionate rose after bariatric surgery and were related to bacterial genera such as Akkermansia, Dialister, and Lachnospiraceae FCS020 group, all known SCFA producers.

CONCLUSIONS

Bariatric surgery helps recruit active BAT in individuals with obesity and is linked to distinct alterations in the gut microbiome and SCFA composition.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov (NCT03168009).

Fasting-induced ketogenesis sensitizes bacteria to antibiotic treatment

Fasting metabolism is a commonly observed motivational response to acute infections and is conceptualized as being beneficial for host survival. Here, we show that fasting potentiates antibiotic treatment for murine sepsis caused by Salmonella Typhimurium, Klebsiella pneumoniae, and Enterobacter cloacae, resulting in increased bacterial clearance and improved host immune responses and survival. This effect is mediated by fasting-induced ketogenesis and could be alternatively implemented by combination therapy with antibiotics and ketone bodies. We show that the ketone body acetoacetate is an effector that sensitizes bacteria to antibiotic treatment by increasing antibiotic lethality and outer and inner membrane permeability. Our results demonstrate that acetoacetate depletes bacterial amino acids, particularly positively charged amino acids and putrescine, leading to cell membrane malfunctions and redox-related lethality. This study reveals an unrecognized role of ketogenesis in antibiotic treatment and a potential ketone body-based treatment strategy for bacterial sepsis.

Time-restricted feeding reduced blood pressure and improved cardiac structure and function by regulating both circulating and local renin-angiotensin systems in spontaneously hypertensive rat model

OBJECTIVE

To investigate whether time-restricted feeding (TRF) can reduce blood pressure (BP) and improve cardiac structure and function in spontaneously hypertensive rats (SHRs) by regulating the renin-angiotensin system (RAS).

METHODS

Wistar Kyoto rats and SHR underwent 16 weeks of TRF intervention, with daily feeding restricted to 9 am-5 pm. The effects of TRF on systolic BP, diastolic BP, mean BP, body weight (BW), heart weight (HW), HW/BW ratio, cardiac structure and function, and RAS activity in the circulating and left ventricular (LV) tissues were investigated.

RESULTS

TRF effectively reduced systolic BP, mean BP, diastolic BP, and BW; improved hypertension-induced cardiac structural and functional damage; and inhibited the ACE-Ang-II-AT1 axis in circulating and LV tissues.

CONCLUSION

TRF effectively inhibits RAS activity in both circulating and LV tissues, thereby lowering BP and mitigating structural and functional cardiac damage associated with hypertension.

The cyclic metabolic switching theory of intermittent fasting

Intermittent fasting (IF) and ketogenic diets (KDs) have recently attracted much attention in the scientific literature and in popular culture and follow a longer history of exercise and caloric restriction (CR) research. Whereas IF involves cyclic metabolic switching (CMS) between ketogenic and non-ketogenic states, KDs and CR may not. In this Perspective, I postulate that the beneficial effects of IF result from alternating between activation of adaptive cellular stress response pathways during the fasting period, followed by cell growth and plasticity pathways during the feeding period. Thereby, I establish the cyclic metabolic switching (CMS) theory of IF. The health benefits of IF may go beyond those seen with continuous CR or KDs without CMS owing to the unique interplay between the signalling functions of the ketone β-hydroxybutyrate, mitochondrial adaptations, reciprocal activation of autophagy and mTOR pathways, endocrine and paracrine signalling, gut microbiota, and circadian biology. The CMS theory may have important implications for future basic research, clinical trials, development of pharmacological interventions, and healthy lifestyle practices.

Mechanisms of Lipid-Associated Macrophage Accrual in Metabolically Stressed Adipose Tissue

Adipose tissue (AT) inflammation, a hallmark of the metabolic syndrome, is triggered by overburdened adipocytes sending out immune cell recruitment signals during obesity development. An AT immune landscape persistent throughout weight loss and regain constitutes an immune-obesogenic memory that hinders long-term weight loss management. Lipid-associated macrophages (LAMs) are emerging as major players in diseased, inflamed metabolic tissues and may be key contributors to an obesogenic memory in AT. Our previous study found that LAM abundance increases with weight loss via intermittent fasting (IF) in obese mice, which is driven by adipocyte p53 signalling. However, the specific signals causing LAM accumulation in AT under IF remain unknown. In this piece, we hypothesise on a range of adipocyte-secreted signals that can harbor immune-attractive features upon fasting/refeeding cycles. We highlight possible mechanisms including cell death signalling, matrikines, and other damage-associated molecular patterns (DAMPs), as well as adipo(-cyto)kines, lipid mediators, metabolites, extracellular vesicles, and epigenetic rewiring. Finally, we consider how advances in mechanisms of AT LAM recruitment gleaned from preclinical models might be translatable to long-term weight management in humans. Thus, we provide vantage points to study signals driving monocyte recruitment, polarisation towards LAMs, and LAM retention, to harness the therapeutic potential of modulating AT LAM levels by impacting the immune-obesogenic memory in metabolic disease.

Intermittent fasting driven different adaptive strategies in Eothenomys miletus (Red-backed vole) at different altitudes: based on the patterns of variations in intestinal microbiota

In the face of global warming, the Eothenomys miletus (Red - backed vole), a species dwelling in highland mountainous regions, is likely to encounter difficulties. Given its restricted mobility, it may struggle with the uncertainty of food resources. In such circumstances, it becomes increasingly crucial for this species to adjust its diverse responses to fulfill its energy requirements. E. miletus specimens were gathered from different altitudes for intermittent fasting (IF) experiments. In these experiments, the specimens underwent random fasting for 3 days within a seven - day cycle. 16 S rDNA sequencing technology, combined with physiological and biochemical assessment methods, was employed to analyze the impacts of IF on gut microorganisms, physiological and biochemical indicators, and the interactions among them. By exploring the adaptive responses of E. miletus to uncertain food resources, which provides novel perspectives on the adaptive strategies of small rodents in the wild during food-scarce periods. The results showed that IF significantly reduced the body mass of E. miletus. Significant correlations were found between various gut microbes and physiological indicators. Under IF conditions, E. miletus at high altitudes experienced a smaller reduction in body mass compared to those at low altitudes. Moreover, the diversity of gut microbes and endemic bacteria in E. miletus at high altitudes varied more than that of low altitudes. The differential response in body mass reduction between high-altitude and low-altitude E. miletus under IF conditions indicated that altitude is an important factor influencing the physiological adaptation of this species to dietary changes. High-altitude E. miletus showed a relatively smaller decrease in body mass, potentially reflecting their better adaptation to environmental stressors over time. Additionally, the greater variation in gut microbe diversity and endemic bacteria in high-altitude E. miletus implied that altitude may shape the gut microbiota, which in turn could be related to their unique physiological adaptations at high altitudes. Overall, E. miletus at high altitude may possess more stable regulatory mechanisms, demonstrating better adaptation under IF conditions. These findings provide valuable insights into the complex interplay between diet, altitude, and gut microbiota in the context of E. miletus physiology, highlighting the importance of considering both environmental and microbial factors in understanding the species' responses to nutritional challenges.​.

Interactions between Gut Microbiota, Host Circadian Rhythms, and Metabolic Diseases

The circadian rhythm arises endogenously from genetically encoded molecular clocks, wherein the components collaborate to induce cyclic fluctuations, occurring approximately every 24 h. The rhythms synchronize biological processes with regular and predictable environmental patterns to guarantee the host metabolism and energy homeostasis function and well-being. Disruptions to circadian rhythms are widely associated with metabolic disorders. Notably, microbial rhythms are influenced by both the host's intrinsic circadian clock and external rhythmic factors (i.e., light-dark cycle, diet patterns, and diet composition), which affect the structure of microbial communities and metabolic functions. Moreover, microbiota and the metabolites also reciprocally influence host rhythms, potentially impacting host metabolic function. This review aimed to explore the bidirectional interactions between the circadian clock, factors influencing host-microbial circadian rhythms, and the effects on lipid metabolism and energy homeostasis.

Integrated Multiomics Analyses Reveal Molecular Insights into How Intermittent Fasting Ameliorates Obesity and Increases Fertility in Male Mice

Background: Intermittent fasting (IF) has been increasingly recognized for its potential to mitigate obesity and diabetes. However, it remains unclear whether IF can alleviate metabolic disorder-induced male infertility. The aim of this study was to investigate the potential of IF to improve fertility outcomes in obese mice. Methods: Eight-week-old C57BL/6J mice were fed a high-fat diet (HFD) for 24 weeks to induce obesity, followed by alternate-day fasting for 6 weeks. We assessed obesity-related metabolic changes and fertility issues postintervention. Comprehensive metabolomic and transcriptomic analyses of serum and testicular samples were used to identify significant metabolic pathway modifications attributable to IF. Results: IF effectively alleviated obesity-induced male infertility, demonstrating significant attenuation of body weight gain and restoration of testicular morphology. IF normalized hypogonadism-associated testosterone depletion and improved sperm parameters. Testis multi-omics integration revealed IF-mediated reprogramming of testicular purine metabolism, coupled with coordinated regulation of glycolipid metabolism and inflammatory-immune homeostasis. Reproductive competence was enhanced as evidenced by statistically elevated successful mating rates and embryonic developmental progression. Serum metabolomics further identified metabolites involved in amino acid metabolism, glycolipid metabolism, and inflammation (e.g., methionine, BCAA, glutathione, and spermidine) may serve as potential targets for treating obesity-related metabolic disorders. Additionally, multidimensional analysis highlighted the crucial role of allantoin in alleviating obesity and related reproductive dysfunction. Conclusions: IF not only resolves obesity-induced metabolic issues but also alleviates male infertility by regulating bioactive metabolites and gene expression linked to glycolipid metabolism, energy homeostasis, and immune responses in the testis. Our study provides a theoretical basis for IF as a clinical treatment for obesity-induced male infertility.

Advances in molecular mechanisms and therapeutic strategies for central nervous system diseases based on gut microbiota imbalance

BACKGROUD

Central nervous system (CNS) diseases pose a serious threat to human health, but the regulatory mechanisms and therapeutic strategies of CNS diseases need to be further explored. It has been demonstrated that the gut microbiota (GM) is closely related to CNS disease. GM structure disorders, abnormal microbial metabolites, intestinal barrier destruction and elevated inflammation exist in patients with CNS diseases and promote the development of CNS diseases. More importantly, GM remodeling alleviates CNS pathology to some extent.

AIM OF REVIEW

Here, we have summarized the regulatory mechanism of the GM in CNS diseases and the potential treatment strategies for CNS repair based on GM regulation, aiming to provide safer and more effective strategies for CNS repair from the perspective of GM regulation.

KEY SCIENTIFIC CONCEPTS OF REVIEW

The abundance and composition of GM is closely associated with the CNS diseases. On the basis of in-depth analysis of GM changes in mice with CNS disease, as well as the changes in its metabolites, therapeutic strategies, such as probiotics, prebiotics, and FMT, may be used to regulate GM balance and affect its microbial metabolites, thereby promoting the recovery of CNS diseases.

Intermittent fasting and neurodegenerative diseases: Molecular mechanisms and therapeutic potential

Neurodegenerative disorders are straining public health worldwide. During neurodegenerative disease progression, aberrant neuronal network activity, bioenergetic impairment, adaptive neural plasticity impairment, dysregulation of neuronal Ca2+ homeostasis, oxidative stress, and immune inflammation manifest as characteristic pathological changes in the cellular milieu of the brain. There is no drug for the treatment of neurodegenerative disorders, and therefore, strategies/treatments for the prevention or treatment of neurodegenerative disorders are urgently needed. Intermittent fasting (IF) is characterized as an eating pattern that alternates between periods of fasting and eating, requiring fasting durations that vary depending on the specific protocol implemented. During IF, depletion of liver glycogen stores leads to the production of ketone bodies from fatty acids derived from adipocytes, thereby inducing an altered metabolic state accompanied by cellular and molecular adaptive responses within neural networks in the brain. At the cellular level, adaptive responses can promote the generation of synapses and neurons. At the molecular level, IF triggers the activation of associated transcription factors, thereby eliciting the expression of protective proteins. Consequently, this regulatory process governs central and peripheral metabolism, oxidative stress, inflammation, mitochondrial function, autophagy, and the gut microbiota, all of which contribute to the amelioration of neurodegenerative disorders. Emerging evidence suggests that weight regulation significantly contributes to the neuroprotective effects of IF. By alleviating obesity-related factors such as blood-brain barrier dysfunction, neuroinflammation, and β-amyloid accumulation, IF enhances metabolic flexibility and insulin sensitivity, further supporting its potential in mitigating neurodegenerative disorders. The present review summarizes animal and human studies investigating the role and underlying mechanisms of IF in physiology and pathology, with an emphasis on its therapeutic potential. Furthermore, we provide an overview of the cellular and molecular mechanisms involved in regulating brain energy metabolism through IF, highlighting its potential applications in neurodegenerative disorders. Ultimately, our findings offer novel insights into the preventive and therapeutic applications of IF for neurodegenerative disorders.

Intermittent fasting regulates gut microbiota and serum metabolome profiles in middle-aged mice fed high-fat diet

BACKGROUND

Intermittent fasting (IF) has received wide attention as an effective diet strategy. Existing studies showed that IF is a promising approach for weight control, improving insulin sensitivity and reducing type 2 diabetes mellitus (T2DM) prevalence.

METHODS

Twenty-eight 8-month-old male C57BL/6J mice were randomly divided into a normal control group (NC), a high-fat diet group (HFD) and an HFD + IF group. Body weight (BW) and food intake were monitored weekly. After 20 weeks, the intraperitoneal glucose tolerance test (IPGTT), oral glucose tolerance test (OGTT), and intraperitoneal insulin tolerance test (IPITT) were performed weekly in sequence. Fresh faeces were collected to examine changes in gut microbiota, and serum untargeted metabolite profiling was conducted on serum samples.

RESULTS

IF significantly reduced weight gain, fat mass and liver weight, improved glucose tolerance and insulin sensitivity in middle-aged mice fed with high-fat diet. 16 S rRNA gene sequencing revealed that IF significantly reduced the Firmicutes/Bacteroidetes (F/B) ratio by increased Muribaculaceae, Bacteroides, Parabacteroides, and decreased Bilophila, Colidextribacter, Oscillibacter. The serum untargeted metabolomics revealed that IF could modulate differential metabolites and metabolic pathways associated with glycolipid metabolism. Spearman's correlation analysis indicated that key differential microbiota were strongly correlated with glucose metabolism-related indicators and serum metabolites such as stearic acid, obeticholic acid, and N-acetylglycine.

CONCLUSIONS

IF improves glucose metabolism, regulates gut microbiota, and alters serum metabolites in middle-aged mice fed a high-fat diet. This provides a new pathway for trials testing diabetes prevention in middle-aged and elderly patients.

Chronic intermittent fasting impairs β cell maturation and function in adolescent mice

Intermittent fasting (IF) is a nutritional lifestyle intervention with broad metabolic benefits, but whether the impact of IF depends on the individual's age is unclear. Here, we investigated the effects of IF on systemic metabolism and β cell function in old, middle-aged, and young mice. Short-term IF improves glucose homeostasis across all age groups without altering islet function and morphology. In contrast, while chronic IF is beneficial for adult mice, it results in impaired β cell function in the young. Using single-cell RNA sequencing (scRNA-seq), we delineate that the β cell maturation and function scores are reduced in young mice. In human islets, a similar pattern is observed in type 1 (T1D), but not type 2 (T2D), diabetes, suggesting that the impact of chronic IF in adolescence is linked to the development of β cell dysfunction. Our study suggests considering the duration of IF in younger persons, as it may worsen rather than reduce diabetes outcomes.

Effect of time-restricted feeding and caloric restriction in metabolic associated fatty liver disease in male rats

BACKGROUND

The prevalence of metabolic associated fatty liver disease (MAFLD) is high. However, there are few studies on the effects of time-restricted feeding (TRF) and caloric restriction (CR) in MAFLD.

OBJECTIVES

To investigate the efficacy and mechanism of 4 h TRF and 60% CR in MAFLD.

METHODS

Twelve male Sprague-Dawley rats were randomly assigned to the Normal group (normal diet, 10 kcal% fat), while the remaining 38 rats were assigned to the MAFLD group (high-fat diet, 60 kcal% fat). 10 weeks later, the MAFLD group was randomly divided into the 4 h TRF, 60% CR, 4 h TRF + 60% CR, and Model groups; all rats were then given normal diet. After 4 weeks, weight, blood lipid, and other indicators were detected.

RESULTS

After the high-fat diet was discontinued, the liver lipid levels in the rat with MAFLD significantly reduced, while the body weight was not significantly changed. The rats in the Model group were heavier than those in the other four groups (p < 0.01). The triglyceride levels were higher in the TRF + CR group compared with the Model group (p < 0.01). Compared with the Model group, 110 metabolites were decreased in the TRF + CR group, and 83 metabolites were elevated in liver. Kyoto Encyclopedia of Genes and Genomes revealed that the mechanism involved the proliferator-activated receptor alpha signaling pathway, metabolic pathway, and so on. We observed differences in silent information regulator transcript 1 (SIRT1) mRNA levels in all five groups (p = 0.003).

CONCLUSIONS

4 h TRF and 60% CR significantly reduced body weight and liver lipid in rats with MAFLD. 4 h TRF can improve MAFLD, and there is no need to excessively restrict food intake.

Achieving healthy aging through gut microbiota-directed dietary intervention: Focusing on microbial biomarkers and host mechanisms

BACKGROUND

Population aging has become a primary global public health issue, and the prevention of age-associated diseases and prolonging healthy life expectancies are of particular importance. Gut microbiota has emerged as a novel target in various host physiological disorders including aging. Comprehensive understanding on changes of gut microbiota during aging, in particular gut microbiota characteristics of centenarians, can provide us possibility to achieving healthy aging or intervene pathological aging through gut microbiota-directed strategies.

AIM OF REVIEW

This review aims to summarize the characteristics of the gut microbiota associated with aging, explore potential biomarkers of aging and address microbiota-associated mechanisms of host aging focusing on intestinal barrier and immune status. By summarizing the existing effective dietary strategies in aging interventions, the probability of developing a diet targeting the gut microbiota in future is provided.

KEY SCIENTIFIC CONCEPTS OF REVIEW

This review is focused on three key notions: Firstly, gut microbiota has become a new target for regulating health status and lifespan, and its changes are closely related to age. Thus, we summarized aging-associated gut microbiota features at the levels of key genus/species and important metabolites through comparing the microbiota differences among centenarians, elderly people and younger people. Secondly, exploring microbiota biomarkers related to aging and discussing future possibility using dietary regime/components targeted to aging-related microbiota biomarkers promote human healthy lifespan. Thirdly, dietary intervention can effectively improve the imbalance of gut microbiota related to aging, such as probiotics, prebiotics, and postbiotics, but their effects vary among.

Gut Microbiota and Osteoarthritis: From Pathogenesis to Novel Therapeutic Opportunities

Osteoarthritis (OA) is the most common chronic degenerative joint disease, characterized by cartilage damage, synovial inflammation, subchondral bone sclerosis, marginal bone loss, and osteophyte development. Clinical manifestations include inflammatory joint pain, swelling, osteophytes, and limitation of motion. The pathogenesis of osteoarthritis has not yet been fully uncovered. With ongoing research, however, it has been gradually determined that OA is not caused solely by mechanical injury or aging, but rather involves chronic low-grade inflammation, metabolic imbalances, dysfunctional adaptive immunity, and alterations in central pain processing centers. The main risk factors for OA include obesity, age, gender, genetics, and sports injuries. In recent years, extensive research on gut microbiota has revealed that gut dysbiosis is associated with some common risk factors for OA, and that it may intervene in its pathogenesis through both direct and indirect mechanisms. Therefore, gut flora imbalance as a pathogenic factor in OA has become a hotspot topic of research, with potential therapeutic connotations. In this paper, we review the role of the gut microbiota in the pathogenesis of OA, describe its relationship with common OA risk factors, and address candidate gut microbiota markers for OA diagnosis. In addition, with focus on OA therapies, we discuss the effects of direct and indirect interventions targeting the gut microbiota, as well as the impact of gut bacteria on the efficacy of OA drugs.

Time-restricted feeding improves metabolic syndrome by activating thermogenesis in brown adipose tissue and reducing inflammatory markers

Background

Obesity and metabolic syndrome (MetS) have become increasingly significant global health issues. Time-restricted feeding (TRF), as a novel dietary intervention, has garnered attention in recent years. However, there is limited research focusing on the effects of TRF on energy expenditure and systemic low-grade inflammation. This study aims to investigate the impact of TRF on weight management, glucose metabolism, insulin resistance, and lipid metabolism in male C57BL/6J mice, particularly in the context of metabolic disorders induced by a high-fat diet (HFD).

Methods

C57BL/6J mice were divided into two groups: a normal diet (ND) group and a high-fat diet (HFD) group. The study duration was 12 weeks. Key parameters observed included body weight, glucose tolerance (via glucose tolerance tests), insulin resistance (HOMA-IR), and insulin secretion under glucose stimulation. Additionally, liver tissue was subjected to Oil Red O staining to assess lipid accumulation, and white and brown adipose tissues were stained with hematoxylin and eosin (HE) to evaluate adipocyte size. The expression of hepatic lipogenesis-related genes (Srebp-c, Chrebp, Fasn, and Acc1) and thermogenic genes in brown adipose tissue (UCP1 and PGC-1α) were also measured. Furthermore, temperature changes in the interscapular brown adipose tissue (BAT) were monitored.

Results

In the ND group: TRF improved insulin resistance and reduced circulating levels of the pro-inflammatory cytokine IL-6, with a slight reduction in body weight.In the HFD group: TRF significantly mitigated weight gain, improved glucose tolerance and insulin resistance, and enhanced insulin secretion under glucose stimulation. Additionally, TRF reduced hepatic steatosis by downregulating the expression of lipogenesis-related genes in the liver. TRF also increased thermogenesis by upregulating the expression of thermogenic genes (UCP1 and PGC-1α) in BAT, while lowering serum levels of pro-inflammatory cytokines IL-6 and TNF-α, though IL-1β levels remained unchanged.

Conclusion

This study demonstrates that TRF can activate thermogenesis in brown adipose tissue and reduce inflammation maker, leading to an improvement in hepatic steatosis and a reduction in white adipose tissue accumulation. These findings suggest that TRF may be a promising intervention for mitigating metabolic disturbances associated with obesity and metabolic syndrome. The study provides mechanistic insights into the beneficial effects of TRF, highlighting its potential in modulating lipid metabolism and exerting anti-inflammatory effects.

Chemical interplay between gut microbiota and epigenetics: Implications in circadian biology

Circadian rhythms are intrinsic molecular mechanisms that synchronize biological functions with the day/night cycle. The mammalian gut is colonized by a myriad of microbes, collectively named the gut microbiota. The microbiota impacts host physiology via metabolites and structural components. A key mechanism is the modulation of host epigenetic pathways, especially histone modifications. An increasing number of studies indicate the role of the microbiota in regulating host circadian rhythms. However, the mechanisms remain largely unknown. Here, we summarize studies on microbial regulation of host circadian rhythms and epigenetic pathways, highlight recent findings on how the microbiota employs host epigenetic machinery to regulate circadian rhythms, and discuss its impacts on host physiology, particularly immune and metabolic functions. We further describe current challenges and resources that could facilitate research on microbiota-epigenetic-circadian rhythm interactions to advance our knowledge of circadian disorders and possible therapeutic avenues.

Structural characterization and anti-obesity effect of a novel water-soluble galactomannan isolated from Eurotium cristatum

Obesity is a serious public health challenge worldwide, the present study is aimed to investigate the structural characteristic and anti-obesity effect of a water-soluble galactomannan (PEC) extracted from Eurotium cristatum (E. cristatum). Detailed analysis of the PEC structure showed a weight-average molecular weight of 32,305 Da and a composition of mainly mannose, galactose and small amounts of glucose. Nuclear magnetic resonance spectroscopy combined with methylation analysis indicated that the main chain of PEC is →5)-β-D-Galf-(1 → 6)-α-D-Manp-(1 → glycosidic bond, and the branched chain →2)-α-D-Manp-(1 → through →2,6)-α-D-Manp-(1 → is connected to the main chain by an O-2 bond. Furthermore, PEC was found to ameliorate body weight gain, metabolic disorders, and to modulate the gut microbiota in HFD-fed mice. Fecal microbiota transplantation trial confirmed that PEC prevented obesity development and metabolic disorders by reversing gut dysbiosis in HFD-fed mice. This is the first report of the isolation of PEC from E. cristatum, and the findings suggested that PEC exerted its antiobesity and related beneficial effects by regulating the gut microbiota. In conclusion, as a polysaccharide, PEC could reduce obesity by modulating the gut microbiota and has potential been a prophylactic agent for obesity and related metabolic diseases.

Gut Microbiome Modulation in Hepatocellular Carcinoma: Preventive Role in NAFLD/NASH Progression and Potential Applications in Immunotherapy-Based Strategies

Hepatocellular carcinoma (HCC) is a heterogeneous tumor associated with several risk factors, with non-alcoholic fatty liver disease (NAFLD) emerging as an important cause of liver tumorigenesis. Due to the obesity epidemics, the occurrence of NAFLD has significantly increased with nearly 30% prevalence worldwide. HCC often arises in the background of chronic liver disease (CLD), such as nonalcoholic steatohepatitis (NASH) and cirrhosis. Gut microbiome (GM) alterations have been linked to NAFLD progression and HCC development, with several investigations reporting a crucial role for the gut-liver axis and microbial metabolites in promoting CLD. Moreover, the GM affects liver homeostasis, energy status, and the immune microenvironment, influencing the response to immunotherapy with interesting therapeutic implications. In this review, we summarize the main changes in the GM and derived metabolites (e.g., short-chain fatty acids and bile acids) occurring in HCC patients and influencing NAFLD progression, emphasizing their potential as early diagnostic biomarkers and prognostic tools. We discuss the weight loss effects of diet-based interventions and healthy lifestyles for the treatment of NAFLD patients, highlighting their impact on the restoration of the intestinal barrier and GM structure. We also describe encouraging preclinical findings on the modulation of GM to improve liver functions in CLD, boost the antitumor immune response (e.g., probiotic supplementations or anti-hypercholesterolemic drug treatment), and ultimately delay NAFLD progression to HCC. The development of safe and effective strategies that target the gut-liver axis holds promise for liver cancer prevention and treatment, especially if personalized options will be considered.

Repeated fasting events sensitize enhancers, transcription factor activity and gene expression to support augmented ketogenesis

Mammals withstand frequent and prolonged fasting periods due to hepatic production of glucose and ketone bodies. Because the fasting response is transcriptionally regulated, we asked whether enhancer dynamics impose a transcriptional program during recurrent fasting and whether this generates effects distinct from a single fasting bout. We found that mice undergoing alternate-day fasting (ADF) respond profoundly differently to a following fasting bout compared to mice first experiencing fasting. Hundreds of genes enabling ketogenesis are 'sensitized' (i.e. induced more strongly by fasting following ADF). Liver enhancers regulating these genes are also sensitized and harbor increased binding of PPARα, the main ketogenic transcription factor. ADF leads to augmented ketogenesis compared to a single fasting bout in wild-type, but not hepatocyte-specific PPARα-deficient mice. Thus, we found that past fasting events are 'remembered' in hepatocytes, sensitizing their enhancers to the next fasting bout and augment ketogenesis. Our findings shed light on transcriptional regulation mediating adaptation to repeated signals.

Gut Microbiota at the Crossroad of Hepatic Oxidative Stress and MASLD

Metabolic dysfunction-associated steatotic liver disease (MASLD) is a prevalent chronic liver condition marked by excessive lipid accumulation in hepatic tissue. This disorder can lead to a range of pathological outcomes, including metabolic dysfunction-associated steatohepatitis (MASH) and cirrhosis. Despite extensive research, the molecular mechanisms driving MASLD initiation and progression remain incompletely understood. Oxidative stress and lipid peroxidation are pivotal in the "multiple parallel hit model", contributing to hepatic cell death and tissue damage. Gut microbiota plays a substantial role in modulating hepatic oxidative stress through multiple pathways: impairing the intestinal barrier, which results in bacterial translocation and chronic hepatic inflammation; modifying bile acid structure, which impacts signaling cascades involved in lipidic metabolism; influencing hepatocytes' ferroptosis, a form of programmed cell death; regulating trimethylamine N-oxide (TMAO) metabolism; and activating platelet function, both recently identified as pathogenetic factors in MASH progression. Moreover, various exogenous factors impact gut microbiota and its involvement in MASLD-related oxidative stress, such as air pollution, physical activity, cigarette smoke, alcohol, and dietary patterns. This manuscript aims to provide a state-of-the-art overview focused on the intricate interplay between gut microbiota, lipid peroxidation, and MASLD pathogenesis, offering insights into potential strategies to prevent disease progression and its associated complications.

Sarcopenia and cachexia: molecular mechanisms and therapeutic interventions

Sarcopenia is defined as a muscle-wasting syndrome that occurs with accelerated aging, while cachexia is a severe wasting syndrome associated with conditions such as cancer and immunodeficiency disorders, which cannot be fully addressed through conventional nutritional supplementation. Sarcopenia can be considered a component of cachexia, with the bidirectional interplay between adipose tissue and skeletal muscle potentially serving as a molecular mechanism for both conditions. However, the underlying mechanisms differ. Recognizing the interplay and distinctions between these disorders is essential for advancing both basic and translational research in this area, enhancing diagnostic accuracy and ultimately achieving effective therapeutic solutions for affected patients. This review discusses the muscle microenvironment's changes contributing to these conditions, recent therapeutic approaches like lifestyle modifications, small molecules, and nutritional interventions, and emerging strategies such as gene editing, stem cell therapy, and gut microbiome modulation. We also address the challenges and opportunities of multimodal interventions, aiming to provide insights into the pathogenesis and molecular mechanisms of sarcopenia and cachexia, ultimately aiding in innovative strategy development and improved treatments.

Intermittent fasting shifts the diurnal transcriptome atlas of transcription factors

Intermittent fasting remains a safe and effective strategy to ameliorate various age-related diseases, but its specific mechanisms are not fully understood. Considering that transcription factors (TFs) determine the response to environmental signals, here, we profiled the diurnal expression of 600 samples across four metabolic tissues sampled every 4 over 24 h from mice placed on five different feeding regimens to provide an atlas of TFs in biological space, time, and feeding regimen. Results showed that 1218 TFs exhibited tissue-specific and temporal expression profiles in ad libitum mice, of which 974 displayed significant oscillations at least in one tissue. Intermittent fasting triggered more than 90% (1161 in 1234) of TFs to oscillate somewhere in the body and repartitioned their tissue-specific expression. A single round of fasting generally promoted TF expression, especially in skeletal muscle and adipose tissues, while intermittent fasting mainly suppressed TF expression. Intermittent fasting down-regulated aging pathway and upregulated the pathway responsible for the inhibition of mammalian target of rapamycin (mTOR). Intermittent fasting shifts the diurnal transcriptome atlas of TFs, and mTOR inhibition may orchestrate intermittent fasting-induced health improvements. This atlas offers a reference and resource to understand how TFs and intermittent fasting may contribute to diurnal rhythm oscillation and bring about specific health benefits.

Dietary Influences on Gut Microbiota and Their Role in Metabolic Dysfunction-Associated Steatotic Liver Disease (MASLD)

Metabolic dysfunction-associated steatotic liver disease (MASLD) is a major contributor to liver-related morbidity, cardiovascular disease, and metabolic complications. Lifestyle interventions, including diet and exercise, are first line in treating MASLD. Dietary approaches such as the low-glycemic-index Mediterranean diet, the ketogenic diet, intermittent fasting, and high fiber diets have demonstrated potential in addressing the metabolic dysfunction underlying this condition. The development and progression of MASLD are closely associated with taxonomic shifts in gut microbial communities, a relationship well-documented in the literature. Given the importance of diet as a primary treatment for MASLD, it is important to understand how gut microbiota and their metabolic byproducts mediate favorable outcomes induced by healthy dietary patterns. Conversely, microbiota changes conferred by unhealthy dietary patterns such as the Western diet may induce dysbiosis and influence steatotic liver disease through promoting hepatic inflammation, up-regulating lipogenesis, dysregulating bile acid metabolism, increasing insulin resistance, and causing oxidative damage in hepatocytes. Although emerging evidence has identified links between diet, microbiota, and development of MASLD, significant gaps remain in understanding specific microbial roles, metabolite pathways, host interactions, and causal relationships. Therefore, this review aims to provide mechanistic insights into the role of microbiota-mediated processes through the analysis of both healthy and unhealthy dietary patterns and their contribution to MASLD pathophysiology. By better elucidating the interplay between dietary nutrients, microbiota-mediated processes, and the onset and progression of steatotic liver disease, this work aims to identify new opportunities for targeted dietary interventions to treat MASLD efficiently.

Effects of Long-Term Fasting on Gut Microbiota, Serum Metabolome, and Their Association in Male Adults

BACKGROUND

Long-term fasting demonstrates greater therapeutic potential and broader application prospects in extreme environments than intermittent fasting.

METHOD

This pilot study of 10-day complete fasting (CF), with a small sample size of 13 volunteers, aimed to investigate the time-series impacts on gut microbiome, serum metabolome, and their interrelationships with biochemical indices.

RESULTS

The results show CF significantly affected gut microbiota diversity, composition, and interspecies interactions, characterized by an expansion of the Proteobacteria phylum (about six-fold) and a decrease in Bacteroidetes (about 50%) and Firmicutes (about 34%) populations. Notably, certain bacteria taxa exhibited complex interactions and strong correlations with serum metabolites implicated in energy and amino acid metabolism, with a particular focus on fatty acylcarnitines and tryptophan derivatives. A key focus of our study was the effect of Ruthenibacterium lactatiformans, which was highly increased during CF and exhibited a strong correlation with fat metabolic indicators. This bacterium was found to mitigate high-fat diet-induced obesity, glucose intolerance, dyslipidemia, and intestinal barrier dysfunction in animal experiments. These effects suggest its potential as a probiotic candidate for the amelioration of dyslipidemia and for mediating the benefits of fasting on fat metabolism.

CONCLUSIONS

Our pilot study suggests that alterations in gut microbiota during CF contribute to the shift of energy metabolic substrate and the establishment of a novel homeostatic state during prolonged fasting.

Transcriptional and Metabolic Changes Following Repeated Fasting and Refeeding of Adipose Stem Cells Highlight Adipose Tissue Resilience

BACKGROUND

Obesity and related metabolic disorders have reached epidemic levels, calling for diverse therapeutic strategies. Altering nutrient intake, timing and quantity by intermittent fasting seems to elicit beneficial health effects by modulating endocrine and cell signaling networks. This study explores the impact of cyclic nutrient availability in the form of every-other-day fasting (EODF) on human adipose stem cells (ASCs).

METHODS

We subjected ASCs to repeated fasting/refeeding (F/R) cycles, mimicking low glucose/high fatty acid (LGHF) conditions, and assessed phenotypic and transcriptomic changes, lipid storage capacity, insulin sensitivity, and differentiation potential.

RESULTS

Four consecutive F/R cycles induced significant changes in adipogenic gene expression, with upregulation of FABP4 and PLIN1 during fasting, and increased lipid storage in the ASCs. Upon differentiation, ASCs exposed to LGHF conditions retained a transient increase in lipid droplet size and altered fatty acid metabolism gene expression until day 9. However, these changes dissipated by day 15 of differentiation, suggesting a limited duration of fasting-induced transcriptional and adipogenic memory. Despite initial effects, ASCs showed resilience, returning to a physiological trajectory during differentiation, with respect to gene expression and lipid metabolism.

CONCLUSIONS

These findings suggest that the long-term effects of EODF on the ASC niche may be transient, emphasizing the ability of the adipose tissue to adapt and restore homeostasis.

The Role of Physical Exercise as a Therapeutic Tool to Improve Lipedema: A Consensus Statement from the Italian Society of Motor and Sports Sciences (Società Italiana di Scienze Motorie e Sportive, SISMeS) and the Italian Society of Phlebology (Società Italiana di Flebologia, SIF)

PURPOSE OF REVIEW

This consensus statement from the Italian Society of Motor and Sports Sciences (Società Italiana di Scienze Motorie e Sportive, SISMeS) and the Italian Society of Phlebology (Società Italiana di Flebologia, SIF) provides the official view on the role of exercise as a non-pharmacological approach in lipedema. In detail, this consensus statement SISMeS - SIF aims to provide a comprehensive overview of lipedema, focusing, in particular, on the role played by physical exercise (PE) in the management of its clinical features.

RECENT FINDINGS

Lipedema is a chronic disease characterized by abnormal fat accumulation. It is often misdiagnosed as obesity, despite presenting distinct pathological mechanisms. Indeed, recent evidence has reported differences in adipose tissue histology, metabolomic profiles, and gene polymorphisms associated with this condition, adding new pieces to the complex puzzle of lipedema pathophysiology. Although by definition lipedema is a condition resistant to diet and PE, the latter emerges for its key role in the management of lipedema, contributing to multiple benefits, including improvements in mitochondrial function, lymphatic drainage, and reduction of inflammation. Various types of exercise, such as aquatic exercises and strength training, have been shown to alleviate symptoms and improve the quality of life of patients with lipedema. However, standardized guidelines for PE prescription and long-term management of patients with lipedema are lacking, highlighting the need for recommendations and further research in this area in order to optimise therapeutic strategies.

A gut microbial metabolite cocktail fights against obesity through modulating the gut microbiota and hepatic leptin signaling

BACKGROUND

Excessive body weight and obesity elevate the risk of chronic non-communicable diseases. The judicious application of the gut microbiome, encompassing both microorganisms and their derived compounds, holds considerable promise in the treatment of obesity.

RESULTS

In this study, we showed that a cocktail of gut microbiota-derived metabolites, comprising indole 3-propionic acid (IPA), sodium butyrate (SB) and valeric acid (VA), alleviated various symptoms of obesity in both male and female mice subjected to a high-fat diet (HFD). The 16S ribosomal RNA (rRNA) sequencing revealed that administering the cocktail via oral gavage retained the gut microbiota composition in obese mice. Fecal microbiota transplantation using cocktail-treated mice as donors mitigated the obesity phenotype of HFD-fed mice. Transcriptomic sequencing analysis showed that the cocktail preserved the gene expression profile of hepatic tissues in obese mice, especially up-regulated the expression level of leptin receptor. Gene delivery via in vivo fluid dynamics further validated that the anti-obesity efficacy of the cocktail was dependent on leptin signaling at least partly. The cocktail also inhibited the expression of appetite stimulators in hypothalamus. Together, the metabolite cocktail combated adiposity by retaining the gut microbiota configuration and activating the hepatic leptin signaling pathway.

CONCLUSIONS

Our findings provide a sophisticated regulatory network between the gut microbiome and host, and highlight a cocktail of gut microbiota-derived metabolites, including IPA, SB, and VA, might be a prospective intervention for anti-obesity in a preclinical setting. © 2024 Society of Chemical Industry.

Effects of Intermittent Fasting on Female Reproductive Function: A Review of Animal and Human Studies

PURPOSE OF REVIEW

Intermittent fasting has gained significant attention, yet a comprehensive understanding of its impact on female reproductive health is lacking. This review aims to fill this gap by examining various intermittent fasting regimens and their effects on female reproductive function, along with potential mechanisms.

RECENT FINDINGS

In healthy non-overweight/obese or pregnant animal models, alternate-day fasting (ADF) and an 8-h time-restricted feeding (TRF) window may have adverse effects on reproductive function. However, these regimens show potential to mitigate negative consequences induced by a high-fat diet (HFD) or environmental exposure. A 10-h TRF demonstrates benefits in improving fertility in both normal-weight and HFD-fed animal models. In women with overweight/obesity or polycystic ovary syndrome (PCOS), the 5:2 diet and TRF significantly reduce the free androgen index while elevating sex hormone binding globulin, promising improvements in menstrual regulation. For pregnant Muslim women, available data do not strongly indicate adverse effects of Ramadan fasting on preterm delivery, but potential downsides to maternal weight gain, neonatal birthweight, and long-term offspring health need consideration. Factors linking intermittent fasting to female reproductive health include the circadian clock, gut microbiota, metabolic regulators, and modifiable lifestyles. Drawing definitive conclusions remains challenging in this evolving area. Nonetheless, our findings underscore the potential utility of intermittent fasting regimens as a therapeutic approach for addressing menstruation irregularities and infertility in women with obesity and PCOS. On the other hand, pregnant women should remain cognizant of potential risks associated with intermittent fasting practices.

Intermittent fasting in health and disease

CONTEXT

Intermittent fasting, a new-age dietary concept derived from an age-old tradition, involves repetitive cycles of fasting/calorie restriction and eating.

OBJECTIVE

We aim to take a deep dive into the biological responses to intermittent fasting, delineate the disease-modifying and cognitive effects of intermittent fasting, and also shed light on the possible side effects.

METHODS

Numerous in vitro and in vivo studies were reviewed, followed by an in-depth analysis, and compilation of their implications in health and disease.

RESULTS

Intermittent fasting improves the body's stress tolerance, which is further amplified with exercise. It impacts various pathological conditions like cancer, obesity, diabetes, cardiovascular disease, and neurodegenerative diseases.

CONCLUSION

During dietary restriction, the human body experiences a metabolic switch due to the depletion of liver glycogen, which promotes a shift towards utilising fatty acids and ketones in the system, thereby significantly impacting adiposity, ageing and the immune response to various diseases.

Cross-talk between adipose tissue and microbiota-gut-brain-axis in brain development and neurological disorder

The gut microbiota is an important factor responsible for the physiological processes as well as pathogenesis of host. The communication between central nervous system (CNS) and microbiota occurs by different pathways i.e., chemical, neural, immune, and endocrine. Alteration in gut microbiota i.e., gut dysbiosis causes alteration in the bidirectional communication between CNS and gut microbiota and linked to the pathogenesis of neurological and neurodevelopmental disorder. Therefore, now-a-days microbiota-gut-brain-axis (MGBA) has emerged as therapeutic target for the treatment of metabolic disorder. But, experimental data available on MGBA from basic research has limited application in clinical study. In present study we first summarized molecular mechanism of microbiota interaction with brain physiology and pathogenesis via collecting data from different sources i.e., PubMed, Scopus, Web of Science. Furthermore, evidence shows that adipose tissue (AT) is active during metabolic activities and may also interact with MGBA. Hence, in present study we have focused on the relationship among MGBA, brown adipose tissue, and white adipose tissue. Along with this, we have also studied functional specificity of AT, and understanding heterogeneity among MGBA and different types of AT. Therefore, molecular interaction among them may provide therapeutic target for the treatment of neurological disorder.

The Role of Gut Microbiota in the Onset and Progression of Obesity and Associated Comorbidities

Obesity, a global public health problem, is constantly increasing, so the concerns in preventing and combating it are increasingly focused on the intestinal microbiota. It was found that the microbiota is different in lean people compared to obese individuals, but the exact mechanisms by which energy homeostasis is influenced are still incompletely known. Numerous studies show the involvement of certain bacterial species in promoting obesity and associated diseases such as diabetes, hypertension, cancer, etc. Our aim is to summarize the main findings regarding the influence of several factors such as lifestyle changes, including diet and bariatric surgery, on the diversity of the gut microbiota in obese individuals. The second purpose of this paper is to investigate the potential effect of various microbiota modulation techniques on ameliorating obesity and its comorbidities. A literature search was conducted using the PubMed database, identifying articles published between 2019 and 2024. Most studies identified suggest that obesity is generally associated with alterations of the gut microbiome such as decreased microbial diversity, an increased Firmicutes-to-Bacteroidetes ratio, and increased SCFAs levels. Our findings also indicate that gut microbiota modulation techniques could represent a novel strategy in treating obesity and related metabolic diseases. Although some mechanisms (e.g., inflammation or hormonal regulation) are already considered a powerful connection between gut microbiota and obesity development, further research is needed to enhance the knowledge on this particular topic.

Fasting as an Adjuvant Therapy for Cancer: Mechanism of Action and Clinical Practice

The fundamental biological characteristics of tumor cells are characterized by irregularities in signaling and metabolic pathways, which are evident through increased glucose uptake, altered mitochondrial function, and the ability to evade growth signals. Interventions such as fasting or fasting-mimicking diets represent a promising strategy that can elicit distinct responses in normal cells compared to tumor cells. These dietary strategies can alter the circulating levels of various hormones and metabolites, including blood glucose, insulin, glucagon, growth hormone, insulin-like growth factor, glucocorticoids, and epinephrine, thereby potentially exerting an anticancer effect. Additionally, elevated levels of insulin-like growth factor-binding proteins and ketone bodies may increase tumor cells' dependence on their own metabolites, ultimately leading to their apoptosis. The combination of fasting or fasting-mimicking diets with radiotherapy or chemotherapeutic agents has demonstrated enhanced anticancer efficacy. This paper aims to classify fasting, elucidate the mechanisms that underlie its effects, assess its impact on various cancer types, and discuss its clinical applications. We will underscore the differential effects of fasting on normal and cancer cells, the mechanisms responsible for these effects, and the imperative for clinical implementation.

Succinic Acid Improves the Metabolism of High-Fat Diet-Induced Mice and Promotes White Adipose Browning

Succinic acid plays a crucial role as an essential intermediate in the mitochondrial tricarboxylic acid cycle in mitochondria. In recent years, growing evidence has supported the the important role of succinic acid in fat metabolism. Therefore, we aimed to investigate the effects of succinic acid on adipose tissue metabolism and insulin sensitivity in high-fat diet (HFD)-induced obese mice and try to explore its potential mechanism. We found that the addition of succinic acid (40 mM) to drinking water inhibited the hypertrophy of inguinal white adipose tissue (iWAT) in HFD-induced mice. Furthermore, succinic acid supplementation enhanced insulin sensitivity and improved their glucose tolerance in obese mice. Interestingly, succinic acid supplementation improved lipid metabolism in HFD-fed mice, as shown by decreased serum levels of TG, TC, LDL-C, and increased HDL-C. In addition, succinic acid supplementation increased the expression of browning markers and mitochondria-related genes in iWAT. Further studies showed that the addition of succinic acid to drinking water promotes the browning of iWAT by activating the PI3K-AKT/MAPK signaling pathway. These results suggest that succinic acid has the potential to be used as an effective component for dietary intervention and may, therefore, play an important role in ameliorating and preventing obesity and associated metabolic diseases caused by HFD.

Glutathione peroxidase 3 is essential for countering senescence in adipose remodelling by maintaining mitochondrial homeostasis

Adipose tissue senescence is a precursor to organismal aging and understanding adipose remodelling contributes to discovering novel anti-aging targets. Glutathione peroxidase 3 (GPx3), a critical endogenous antioxidant enzyme, is diminished in the subcutaneous adipose tissue (sWAT) with white adipose expansion. Based on the active role of the antioxidant system in counteracting aging, we investigated the involvement of GPx3 in adipose senescence. We determined that knockdown of GPx3 in adipose tissue by adeno-associated viruses impaired mitochondrial function in mice, increased susceptibility to obesity, and exacerbated adipose tissue senescence. Impairment of GPx3 may cause mitochondrial dysfunction through inner mitochondrial membrane disruption. Adipose reshaping management (cold stimulation and intermittent diet) counteracted the aging of tissues, with an increase in GPx3 expression. Overall metabolic improvement induced by cold stimulation was partially attenuated when GPx3 was depleted. GPx3 may be involved in adipose browning by interacting with UCP1, and GPx3 may be a limiting factor for intracellular reactive oxygen species (ROS) accumulation during stem cell browning. Collectively, these findings emphasise the importance of restoring the imbalanced redox state in adipose tissue to counteract aging and that GPx3 may be a potential target for maintaining mitochondrial homeostasis and longevity.

Intermittent Fasting-Induced Orm2 Promotes Adipose Browning via the GP130/IL23R-p38 Cascade

Intermittent fasting (IF) plays a critical role in mitigating obesity, yet the precise biological mechanisms require further elucidation. Here Orosomucoid 2 (Orm2) is identified as an IF-induced hepatokine that stimulates adipose browning. IF induced Orm2 expression and secretion from the liver through peroxisome proliferator-activated receptor alpha (PPARα). In adipose tissue, Orm2 bound to glycoprotein 130/interleukin 23 receptor (GP130/IL23R) and promoted adipose browning through the activation of p38 mitogen-activated protein kinases (p38-MAPK). In obese mice, Orm2 led to a significant induction of adipose tissue browning and subsequent weight loss, an effect that is not replicated by a mutant variant of Orm2 deficient in GP130/IL23R binding capability. Crucially, genetic association studies in humans identified an obesity-associated Orm2 variant (D178E), which shows decreased GP130/IL23R binding and impaired browning capacity in mice. Overall, the research identifies Orm2 as a promising therapeutic target for obesity, mediating adipose browning through the GP130/IL23R-p38 signalling pathway.

Gut microbiota dysbiosis-mediated ceramides elevation contributes to corticosterone-induced depression by impairing mitochondrial function

The role of gut microbiota (GM) dysbiosis in the pathogenesis of depression has received widespread attention, but the mechanism remains elusive. Corticosterone (CORT)-treated mice showed depression-like behaviors, reduced hippocampal neurogenesis, and altered composition of the GM. Fecal microbial transplantation from CORT-treated mice transferred depression-like phenotypes and their dominant GM to the recipients. Fecal metabolic profiling exposed remarkable increase of gut ceramides in CORT-treated and recipient mice. Oral gavage with Bifidobacterium pseudolongum and Lactobacillus reuteri could induce elevations of gut ceramides in mice. Ceramides-treated mice showed depressive-like phenotypes, significant downregulation of oxidative phosphorylation-associated genes, and hippocampal mitochondrial dysfunction. Our study demonstrated a link between chronic exposure to CORT and its impact on GM composition, which induces ceramides accumulation, ultimately leading to hippocampal mitochondrial dysfunction. This cascade of events plays a critical role in reducing adult hippocampal neurogenesis and is strongly associated with the development of depression-like behaviors.

A Systematic Review of the Effect of Polyphenols on Alterations of the Intestinal Microbiota and Shared Bacterial Profiles Between Metabolic Syndrome and Acne

Introduction: Microbiota, composed of micro-organisms like bacteria, viruses, and non-pathogenic fungi, plays a crucial role in digestion, vitamin production, and protection against dangerous microbes. Several factors, including age, diet, alcohol consumption, stress, environmental microorganisms, and therapies (particularly antibiotics), as well as birth and nursing, could modify the microbiota. Recent research has highlighted its alteration and involvement in a various disease, including metabolic syndrome and acne. This systematic review aimed to identify common biomarkers and microbiota alterations shared between metabolic syndrome and acne, and to explore how the potential prebiotic activities of polyphenols may promote intestinal eubiosis. Materials and methods: A comprehensive search in PubMed and EMBASE resulted in 4142 articles, from which nine studies were selected based on specific criteria after removing duplicates and reviewing abstracts and full texts. All studies correlated the microbiota alteration in both pathologies and the activity of polyphenols in metabolic syndrome. Results: This review suggests that acne may be influenced by some of the same microorganisms involved in metabolic syndrome. While the literature highlights the effectiveness of polyphenols in treating metabolic syndrome, no studies have yet demonstrated their specific impact on acne. Conclusions: The research points to the potential benefits of polyphenols in modulating the microbiota, which could be relevant for individuals with metabolic syndrome. However, due to the limited data available, it was not possible to establish a direct correlation between metabolic syndrome and acne.

Novel approach for ameliorating high-fat diet-induced syndromes via probiotic-fermented oyster mushroom: from metabolites and microbiota to regulation mechanisms

The potential effects of probiotics on lowering lipid accumulation and alleviating gut microbiota perturbation have been extensively substantiated, but whether Lactobacillus rhamnoses-fermented oyster mushroom (FOM) could more pronouncedly attenuate obesity remains unclear. In this study, the anti-obesity effect of FOM was estimated based on the gut microbiota profile and analysis of hepatic lipid metabolic characteristics. The results revealed that FOM intervention dramatically improved hepatic lipid accumulation, characterized by reduction in fat-related factor metabolism levels and liver lesion enzymatic activities and down-regulation of the expression of genes associated with glycolipid metabolism (Foxo1, Gck, G6pd, Il6r and IL-β). Metabolomics analysis indicated HFD-induced dysglycaemia and disturbed amino acid metabolism, characterized by significant enrichment of pathways (butanoate metabolism, arginine biosynthesis, etc.) and elevated levels of D-mannose, succinate and β-D-fructose, followed by a decreased galactitol content. Furthermore, FOM intervention showed significant enrichment of specific pathways, particularly transcriptional misregulation in cancer and FoxO signaling pathways, while the MAPK signaling pathway demonstrated consistent enrichment across all experimental groups. FOM intervention reshaped the gut microbiota structure by facilitating the proliferation of SCFA producers (Romboutsia, Ruminococcaceae and Allobaculum), together with the depletion of Lachnospiraceae population. The current study strengthened our understanding of FOM prebiotic activities and obesity alleviation mechanisms.

Cold Exposure Alleviates T2DM Through Plasma-Derived Extracellular Vesicles

Purpose

Anecdotal reports have praised the benefits of cold exposure, exemplified by activities like winter swimming and cold water immersion. Cold exposure has garnered acclaim for its potential to confer benefits and potentially alleviate diabetes. We posited that systemic cold temperature (CT, 4-8°C) likely influences the organism's blood components through ambient temperature, prompting our investigation into the effects of chronic cold exposure on type 2 diabetic (T2DM) mice and our initial exploration of how cold exposure mitigates the incidence of T2DM.

Methods

The effects of CT (4-8°C) or room temperature (RT, 22-25°C) on T2DM mice were investigated. Mice blood and organ specimens were collected for fully automated biochemical testing, ELISA, HE staining, immunohistochemistry, and immunofluorescence. Glucose uptake was assessed using flow cytometry with 2-NBDG. Changes in potential signaling pathways such as protein kinase B (AKT), phosphorylated AKT (p-AKT), insulin receptor substrates 1 (IRS1), and phosphorylated IRS1 (p-IRS1) were evaluated by Western blot.

Results

CT or CT mice plasma-derived extracellular vesicles (CT-EVs) remarkably reduced blood glucose levels and improved insulin sensitivity in T2DM mice. This treatment enhanced glucose metabolism, systemic insulin sensitivity, and insulin secretion function while promoting glycogen accumulation in the liver and muscle. Additionally, CT-EVs treatment protected against the streptozocin (STZ)-induced destruction of islets in T2DM mice by inhibiting β-cell apoptosis. CT-EVs also shielded islets from destruction and increased the expression of p-IRS1 and p-AKT in adipocytes and hepatocytes. In vitro experiments further confirmed its pro-insulin sensitivity effect.

Conclusion

Our data indicate that cold exposure may have a potentially beneficial effect on the development of T2DM, mainly through the anti-diabetic effect of plasma-derived EVs released during cold stimulation. This phenomenon could significantly contribute to understanding the lower prevalence of diabetes in colder regions.

A detective story of intermittent fasting effect on immunity

Intermittent fasting (IF) refers to periodic fasting routines, that caloric intake is minimized not by meal portion size reduction but by intermittently eliminating ingestion of one or several consecutive meals. IF can instigate comprehensive and multifaceted alterations in energy metabolism, these metabolic channels may aboundingly function as primordial mechanisms that interface with the immune system, instigating intricate immune transformations. This review delivers a comprehensive understanding of IF, paying particular attention to its influence on the immune system, thus seeking to bridge these two research domains. We explore how IF effects lipid metabolism, hormonal levels, circadian rhythm, autophagy, oxidative stress, gut microbiota, and intestinal barrier integrity, and conjecture about the mechanisms orchestrating the intersect between these factors and the immune system. Moreover, the review includes research findings on the implications of IF on the immune system and patients burdened with autoimmune diseases.

Adipose Tissue Plasticity: A Comprehensive Definition and Multidimensional Insight

Adipose tissue is composed of adipocytes, stromal vascular fraction, nerves, surrounding immune cells, and the extracellular matrix. Under various physiological or pathological conditions, adipose tissue shifts cellular composition, lipid storage, and organelle dynamics to respond to the stress; this remodeling is called "adipose tissue plasticity". Adipose tissue plasticity includes changes in the size, species, number, lipid storage capacity, and differentiation function of adipocytes, as well as alterations in the distribution and cellular composition of adipose tissue. This plasticity has a major role in growth, obesity, organismal protection, and internal environmental homeostasis. Moreover, certain thresholds exist for this plasticity with significant individualized differences. Here, we comprehensively elaborate on the specific connotation of adipose tissue plasticity and the relationship between this plasticity and the development of many diseases. Meanwhile, we summarize possible strategies for treating obesity in response to adipose tissue plasticity, intending to provide new insights into the dynamic changes in adipose tissue and contribute new ideas to relevant clinical problems.

A liver-fat crosstalk for iron flux during healthy beiging of adipose tissue

Beiging of adipocytes is characteristic of a higher number of mitochondria, the central hub of metabolism in the cell. However, studies show that beiging can improve metabolic health or cause metabolic disorders. Here we discuss a liver-fat crosstalk for iron flux associated with healthy beiging of adipocytes. Deletion of the transcription factor FoxO1 in adipocytes (adO1KO mice) induces a higher iron flux from the liver to white adipose tissue, concurrent with augmented mitochondrial biogenesis that increases iron demands. In addition, adO1KO mice adopt an alternate mechanism to sustain mitophagy, which enhances mitochondrial quality control, thereby improving mitochondrial respiratory capacity and metabolic health. However, the liver-fat crosstalk is not detectable in adipose Atg7 knockout (ad7KO) mice, which undergo beiging of adipocytes but have metabolic dysregulation. Autophagic clearance of mitochondria is blocked in ad7KO mice, which accumulates dysfunctional mitochondria and elevates mitochondrial content but lowers mitochondrial respiratory capacity. Mitochondrial biogenesis is comparable in the control and ad7KO mice, and the iron influx into adipocytes and iron efflux from the liver remain unchanged. Therefore, activation of the liver-fat crosstalk is critical for mitochondrial quality control that underlies healthy beiging of adipocytes.

Intermittent fasting and high-intensity interval training do not alter gut microbiota composition in adult women with obesity

Obesity is advancing at an accelerated pace, and yet its treatment is still an emerging field. Although studies have demonstrated the role of the microbiota in the pathogenesis of obesity, this is the first study to show the effects of intermittent fasting (IF), combined or not with exercise, and high-intensity interval training (HIIT) on the gut microbiota composition in women with obesity. Our hypothesis is that IF combined with HIIT can promote the remodeling of the composition and function of the gut microbiota. Thirty-six women with obesity, aged between 18 and 40 yr, participated in the study. They were randomly divided into three groups: 1) IF associated with HIIT group [IF + exercise group (EX), n = 15]; 2) HIIT group (EX, n = 11); and 3) IF group (IF, n = 10). Interventions took place over 8 wk, and all assessments were performed preintervention and postintervention. The HIIT circuit was performed 3 times/wk, for 25 min/session. The IF protocol was a 5:2 (2 times/wk). Multiplex analysis of inflammatory cytokines, sequencing of the 16S rRNA gene, and gas chromatography to measure fecal concentrations of short-chain fatty acids (SCFAs) were performed. This study was registered on ClinicalTrials.gov (NCT05237154). Exercise increased fecal acetate concentrations (P = 0.04), but no changes were observed in the composition and functional profile of the microbiota. The interventions did not change the composition of the microbiota, but exercise may play a modulatory role in the production of acetate. This investigation provides clinical insights into the use of IF and HIIT for women with obesity.NEW & NOTEWORTHY This is the first investigation about alternate-day fasting combined with HITT on the gut microbiota of obese women. The study contributes to the advancement of human science involving IF and HIIT, popular strategies for managing obesity. Previous evidence has explored IF in modulating the microbiota in animal models or specific populations and clinical conditions. Despite the subtle outcomes, this study has relevance and originality in the field of gut microbiota knowledge.