Intermittent fasting promotes adipose thermogenesis and metabolic homeostasis via VEGF-mediated alternative activation of macrophage

Gpr109A in TAMs promoted hepatocellular carcinoma via increasing PKA/PPARγ/MerTK/IL-10/TGFβ induced M2c polarization

To delineate Gpr109A's role and mechanisms in modulating the immune microenvironment of hepatocellular carcinoma. Employing Gpr109A-knockout mice and in vitro co-cultures of hepatocellular carcinoma cells with macrophages, this study utilized a suite of techniques, including lentiviral vectors for stable cell line establishment, Western blotting, cell scratch, CCK-8, transwell assays, flow cytometry, immunohistochemistry and phagocytosis assay to assess various cellular behaviors and interactions. Gpr109A deletion markedly reduced the oncogenic potential of H22 cells, both in vivo and when co-cultured with knockout macrophages, impairing their growth, invasion, and migration. In Gpr109A-knockout macrophages, an upregulation of MerTK and a reduction in immunosuppressive cytokine release were observed, indicating a shift towards an M2c macrophage phenotype. This shift is linked to Gpr109A's role in promoting protease overexpression and inhibiting SHP2 phosphorylation, crucial for enhancing cancer cell proliferation and invasiveness. Gpr109A significantly influences macrophage polarization to the M2c type, augmenting hepatocellular carcinoma cell aggressiveness.

The role of dietary inflammatory index in metabolic diseases: the associations, mechanisms, and treatments

In recent years, the prevalence of metabolic diseases has increased significantly, posing a serious threat to global health. Chronic low-grade inflammation is implicated in the development of most metabolic diseases, such as type 2 diabetes mellitus (T2DM), obesity, dyslipidemia, and cardiovascular disease, serving as a link between diet and these conditions. Increasing attention has been directly toward dietary inflammatory patterns that may prevent or ameliorate metabolic diseases. The Dietary Inflammatory Index (DII) was developed to assess the inflammatory potential of dietary intake. Consequently, a growing body of research has examined the associations between the DII and the risk of several metabolic diseases. In this review, we explore the current scientific literature on the relationships between the DII, T2DM, obesity, and dyslipidemia. It summarizes recent findings and explore potential underlying mechanisms from two aspects: the interaction between diet and inflammation, and the link between inflammation and metabolic diseases. Furthermore, this review discusses the therapeutic strategies, including dietary modifications, prebiotics, and probiotics, and discusses the application of the DII in metabolic diseases, as well as future research directions.

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.

Immunomodulatory effects of calorie restriction and its mimetics: A new potential therapeutic approach for autoimmune diseases

Calorie restriction (CR) is a well known intervention associated with multifaceted anti-aging and pro-longevity health benefits. It induces complex physiological cellular and molecular adaptations, resulting in the fine-tuning of metabolic and immune responses in both homeostatic and diseased states. It has thus been extensively studied both preclinically and clinically, uncovering its therapeutic potential against inflammatory conditions, particularly autoimmune diseases. CR mimetics (CRMs), that is, molecules that mimic CR's effects, have also been widely investigated to counteract inflammatory states associated with numerous diseases, including autoimmunity. However, a comprehensive overview of how CR and CRMs modulate different aspects of immune responses, thereby potentially modifying autoimmunity, is still lacking. Here, we reviewed the latest progress on the impacts of CR and CRMs on the immune system and the current evidence on their potential translation in the clinical management of people with autoimmune diseases. First, we summarized different types of CR and CRMs and their main mechanisms of action. We next reviewed comprehensively how CR and CRMs modulate immune cells and discussed up-to-date preclinical and clinical advances in using CR and CRMs in the context of some of the most common autoimmune diseases. Finally, challenges faced in CR-related research and its translation into the clinic are discussed. SIGNIFICANCE STATEMENT: Calorie restriction (CR) encompasses various approaches for daily or intermittent reduction in calorie intake while maintaining adequate nutrient intake. It acts through cell-intrinsic and -extrinsic pathways to modulate immune cell functions. CR is emerging as a strategy for autoimmune disease management. CR's effects could be partially mimicked by molecules called CR mimetics, which are proposed to achieve CR's effects without reducing food intake. CR and CR mimetics have been tested as promising potential therapeutics in preclinical and clinical autoimmune disease studies.

Short-term starvation inhibits CD36 N-glycosylation and downregulates USP7 UFMylation to alleviate RBPJ-maintained T cell exhaustion in liver cancer

Rationale: Short-term starvation (STS) has been shown to enhance the sensitivity of tumors to chemotherapy while concurrently safeguarding normal cells from its detrimental side effects. Nonetheless, the extent to which STS relies on the anti-tumor immune response to impede the progression of hepatocellular carcinoma (HCC) remains uncertain. Methods: In this study, we employed mass cytometry, flow cytometry, immunoprecipitation, immunoblotting, CUT&Tag, RT-qPCR, and DNA pull-down assays to evaluate the relationship between STS and T-cell antitumor immunity in HCC. Results: We demonstrated that STS alleviated T cell exhaustion in HCC. This study elucidated the mechanism by which STS blocked CD36 N-glycosylation, leading to the upregulation of AMPK phosphorylation and the downregulation of USP7 UFMylation, thus enhancing ubiquitination and destabilized USP7. Consequently, diminished USP7 levels facilitated the ubiquitination and subsequent degradation of RBPJ, thereby inhibiting T cell exhaustion through the IRF4/TNFRSF1B axis. From a therapeutic standpoint, STS not only suppressed the growth of patient-derived orthotopic xenografts but also enhanced their sensitivity to immunotherapy. Conclusions: These findings uncovered a novel mechanism by which N-glycosylation participated in UFMylation/ubiquitination to regulate T cell exhaustion, and we underscored the potential of targeting USP7 and RBPJ in anti-tumor immunotherapy strategies.

Postoperative Intermittent Fasting Improves Outcome of Autologous Fat Grafting in Mice

BACKGROUND

Autologous fat grafting confronts challenges of inconsistent retention and complications. Intermittent fasting (IF), an emerging dietary management strategy, shows potential in tissue repair and fat metabolism, and yet to know in fat grafting.

OBJECTIVES

The aim of this study is to address the impact of 16:8 IF on the outcome of fat grafting in mice.

METHODS

Male C57BL/6 mice were randomly assigned to postoperative IF regimen group (n = 24) and ad libitum group with unrestricted feeding (n = 24). For postoperative IF group, animals were put on a feeding schedule with 8 hours of unrestricted access to standard diet per day followed by 16-h fasting period after fat grafting. Fat grafts were harvested at 2, 4 and 12 weeks postoperatively. We addressed the mass retention and graft quality through weighting and ultrasound examination. Histological remodeling of fat grafts was evaluated by Masson staining and immunofluorescence staining.

RESULTS

In comparison with unrestricted feeding, postoperative IF strategies improved the mass retention of fat grafts, and optimized the outcomes characterized by enhanced adipogenesis, accelerated revascularization, facilitated M2 macrophage infiltration as well as reduced fibrosis and oil cyst formation.

CONCLUSION

Postoperative IF improved the retention and outcomes of fat grafting in mice, and could be suggested as a dietary intervention strategy after fat grafting clinically.

NO LEVEL ASSIGNED

This journal requires that authors assign a level of evidence to each submission to which Evidence-Based Medicine rankings are applicable. This excludes Review Articles, Book Reviews, and manuscripts that concern Basic Science, Animal Studies, Cadaver Studies, and Experimental Studies. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Adipocyte ZAG improves obesity-triggered insulin resistance by reshaping macrophages populations in adipose tissue

Adipose tissues macrophages (ATMs) serve as a critical effector in the mediating occurrence of metabolic inflammation to impact whole-body insulin sensitivity in obesity. Discovering the key adipokines mediating crosstalk of adipocytes-macrophages and understanding the molecular mechanism of ATMs polarization and function have become hot topic issues in the immunometabolism fields. Zinc-α2-glycoprotein (ZAG) as a anti-inflammatory adipokines plays important roles in obesity-related metabolic diseases. We attempt to explore the precise role of adipose ZAG in metabolic inflammation and obesity-associated insulin resistance. Here we showed that Omental ZAG was positively associated with insulin sensitivity and M2 macrophages markers. ZAG-specific ablation in adipocyte aggravated insulin resistance and adipose tissues inflammation as evidenced by enhanced M1 macrophages proportion and inhibited AKT signaling pathway in mice fed with a high-fat diet. Exogenous ZAG inhibits PA-induced M1 macrophage polarization via β3-AR/PKA/STAT3 signaling in RAW264.7 macrophages.These findings suggest that adipocyte ZAG maintain insulin sensitivity via the cross talk with adipose-resident macrophages.

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.

Can Exercise-Mediated Adipose Browning Provide an Alternative Explanation for the Obesity Paradox?

Overweight patients with cardiovascular disease (CVD) tend to survive longer than normal-weight patients, a phenomenon known as the "obesity paradox". The phenotypic characteristics of adipose distribution in these patients (who survive longer) often reveal a larger proportion of subcutaneous white adipose tissue (scWAT), suggesting that the presence of scWAT is negatively associated with all-cause mortality and that scWAT appears to provide protective benefits in patients facing unhealthy states. Exercise-mediated browning is a crucial aspect of the benign remodeling process of adipose tissue (AT). Reduced accumulation, reduced inflammation, and associated adipokine secretion are directly related to the reduction in CVD mortality. This paper summarized the pathogenetic factors associated with AT accumulation in patients with CVD and analyzed the possible role and pathway of exercise-mediated adipose browning in reducing the risk of CVD and CVD-related mortality. It is suggested that exercise-mediated browning may provide a new perspective on the "obesity paradox"; that is, overweight CVD patients who have more scWAT may gain greater cardiovascular health benefits through exercise.

Hypoxia signaling in the adipose tissue

Obesity per se is rapidly emerging all over the planet and further accounts for many other life-threatening conditions, such as diabetes, cardiovascular diseases, and cancers. Decreased oxygen supply or increased relative oxygen consumption in the adipose tissue results in adipose tissue hypoxia, which is a hallmark of obesity. This review aims to provide an up-to-date overview of the hypoxia signaling in the adipose tissue. First, we summarize literature evidence to demonstrate that hypoxia is regularly observed during adipose tissue remodeling in humans and rodent models with obesity. Next, we discuss how hypoxia-inducible factors (HIFs) are regulated and how adipose tissues behave in response to hypoxia. Then, the differential roles of adipose HIF-1α and HIF-2α in adipose tissue biology and obesity pathology are highlighted. Finally, the review emphasizes the importance of modulating adipose hypoxia as a therapeutic avenue to assist adipose tissues in functionally adapting to hypoxic conditions, ultimately promoting adipose health and improving outcomes due to obesity.

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.

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.

Fasting the brain for mental health

Unfavorable socioeconomic and geopolitical conditions such as poverty, violence and inequality increase vulnerability to mental disorders. Also, exposure to a poor nutrition such as high-energy dense (HED) diets has been linked to alterations in brain function, leading to anxiety, addiction, and depression. HED diets rich in saturated fatty acids or obesity can activate the innate immune system in the brain, especially microglia, increasing proinflammatory cytokines such as interleukin 1 beta (IL1-β) and interleukin 6 (IL-6), in part, by the stimulation of toll-like receptor 4 (TLR4) and the nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) pathway. Intermittent fasting (IF), an eating protocol characterized by alternating periods of fasting with periods of eating, has gained recognition as a weight-management strategy to reduce obesity. Accordingly, during IF inflammation and brain function can be modulated by production of ketone bodies and modulation of the intestinal microbiota, which also promote the induction of brain-derived neurotrophic factor (BDNF), which is involved in neurogenesis and neuronal plasticity. Although IF has contributed to reduce body weight and improve metabolic profiles, its influence on mental health remains an evolving field of research. Here, we provide experimental evidence supporting the role of IF reducing neuroinflammation as a valuable approach to improve mental health.

Alarmins and their pivotal role in the pathogenesis of spontaneous abortion: insights for therapeutic intervention

Alarmins are a class of molecules released when affected cells damaged or undergo apoptosis. They contain various chemotactic and immunomodulatory proteins or peptides. These molecules regulate the immune response by interacting with pattern recognition receptors (PRRs) and play important roles in inflammatory response, tissue repair, infection defense, and cancer treatment. Spontaneous abortion (SA) is a common pregnancy-related disease, and its pathogenesis has been puzzling clinicians, so it needs to be further studied. In this paper, we first reviewed the research status of various alarmins and SA, focusing on the role of high mobility box 1 (HMGB1), interleukin33 (IL-33), interleukin1β (IL-1β) and S-100 protein (S100 protein) in immune response, inflammation, embryonic development and abortion. Subsequently, this paper summarized the effect of alarmins on pregnancy outcome by influencing angiogenesis-related factors. Finally, from the perspective of aseptic inflammation, the pro-inflammatory signaling pathways involved in various alarmins and their targeted drugs were reviewed. By focusing on specific molecules in alarmins and their receptors and signaling pathways, we can more accurately conduct drug research and development. The purpose of this review is to explore the role of alarmins in SA, and provide important references for early detection of abortion risk, revealing the disease mechanism, developing new therapies and improving the prognosis of patients.

Effects of time-restricted feeding (TRF)-model of intermittent fasting on adipose organ: a narrative review

Time-restricted feeding (TRF), an intermittent fasting approach involving a shortened eating window within 24 h, has gained popularity as a weight management approach. This review addresses how TRF may favor fat redistribution and the function of the adipose organ. TRF trials (mainly 16:8 model, with a duration of 5-48 weeks) reported a significant weight loss (1.2-10.2%, ~ 1.4-9.4 kg), with a considerable decrease in total fat mass (1.6-21%, ~ 0.5-7 kg) and visceral adipose compartment (VAC, 11-27%) in overweight and obese subjects. Experimental TRF in normal-fed and obesogenic-diet-fed mice and rats (with a fasting duration ranging between 9 and 21 h within 1-17 weeks) reported a significant reduction in body weight (~ 7-40%), total fat mass (~ 17-71%), and intrahepatic fat (~ 25-72%). TRF also improves VAC and subcutaneous adipose compartment (SAC) function by decreasing adipocyte size, macrophage infiltration, M1-macrophage polarity, and downregulating inflammatory genes. In conclusion, beyond its effect on body weight loss, total fat mass, and intrahepatic fat accumulation, TRF favors adipose organ fat redistribution in overweight and obese subjects by decreasing VAC and improving the function of VAC and SAC.

Noradrenergic Projections from the Locus Coeruleus to the Medial Prefrontal Cortex Enhances Stress Coping Behavior in Mice Following Long-Term Intermittent Fasting

Intermittent fasting has been shown to alleviate stress, anxiety, and depressive symptoms. Although noradrenaline, also known as norepinephrine (NE), is implicated in stress regulation, the dynamics of NE release and the associated neural pathways during stress coping behaviors in fasting mice remain poorly understood. In this study, we employed the forced swimming test (FST) to evaluate the effects of intermittent fasting on stress coping behavior in mice. Our results demonstrate that mice subjected to long-term intermittent fasting exhibited significantly more active coping behaviors in the FST compared to control mice. In contrast, acute fasting did not produce similar effects. Using the fluorescent GRAB-NE sensor to measure NE release with sub-second temporal resolution during the FST, we found that intermittent fasting modulates the locus coeruleus-medial prefrontal cortex (LC-mPFC) pathway, which underlies these behavioral adaptations. Moreover, chemogenetic activation of LC-mPFC projections strongly promoted active coping in the FST. These findings suggest that enhanced LC-mPFC activity mediates the increased active coping behavior observed in fasting mice. This study provides new insights into the neural mechanisms through which intermittent fasting may ameliorate depressive-like behaviors, offering potential therapeutic targets for stress-related disorders.

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.

Intermittent Fasting Improves Insulin Resistance by Modulating the Gut Microbiota and Bile Acid Metabolism in Diet-Induced Obesity

SCOPE

Adipose tissue macrophages (ATMs) are crucial in the pathogenesis of insulin resistance (IR). Intermittent fasting (IF) is an effective intervention for obesity. However, the underlying mechanism by which IF improves IR remains unclear.

METHODS AND RESULTS

Male C57BL/6J mice are fed chow-diet and high-fat diet (HFD) for 12 weeks, then is randomized into ad libitum feeding or every other day fasting for 8 weeks. Markers of ATMs and expression of uncoupling protein 1 (UCP-1) are determined. Gut microbiota and bile acids (BAs) are profiled using 16S rRNA sequencing and targeted metabolomics analysis. Results indicate that IF improves IR in HFD-induced obesity. IF decreases ATM infiltration, pro-inflammatory M1 gene expression, and promotes white adipose tissue (WAT) browning by elevating UCP-1 expression. IF restructures microbiota composition, significantly expanding the abundance of Verrucomicrobia particularly Akkermansia muciniphila, with the decrease of that of Firmicutes. IF increases the level of total BAs and alters the composition of BAs with higher proportion of 12α-hydroxylated (12α-OH) BAs. The changes in these BAs are correlated with differential bacteria.

CONCLUSION

The findings indicate that IF improves IR partially mediated by the interplay between restructured gut microbiota and BAs metabolism, which has implications for the dietary management in obesity.

Macrophages and T cells in metabolic disorder-associated cancers

Cancer and metabolic disorders have emerged as major global health challenges, reaching epidemic levels in recent decades. Often viewed as separate issues, metabolic disorders are shown by mounting evidence to heighten cancer risk and incidence. The intricacies underlying this connection are still being unraveled and encompass a complex interplay between metabolites, cancer cells and immune cells within the tumour microenvironment (TME). Here, we outline the interplay between metabolic and immune cell dysfunction in the context of three highly prevalent metabolic disorders, namely obesity; two associated liver diseases, metabolic dysfunction-associated steatotic liver disease (MASLD) and metabolic dysfunction-associated steatohepatitis (MASH); and type 2 diabetes. We focus primarily on macrophages and T cells, the critical roles of which in dictating inflammatory response and immune surveillance in metabolic disorder-associated cancers are widely reported. Moreover, considering the ever-increasing number of patients prescribed with metabolism disorder-altering drugs and diets in recent years, we discuss how these therapies modulate systemic and local immune phenotypes, consequently impacting cancer malignancy. Collectively, unraveling the determinants of metabolic disorder-associated immune landscape and their role in fuelling cancer malignancy will provide a framework essential to therapeutically address these highly prevalent diseases.

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.

Intermittent fasting influences immunity and metabolism

Intermittent fasting (IF) modifies cell- and tissue-specific immunometabolic responses that dictate metabolic flexibility and inflammation during obesity and type 2 diabetes (T2D). Fasting forces periods of metabolic flexibility and necessitates increased use of different substrates. IF can lower metabolic inflammation and improve glucose metabolism without lowering obesity and can influence time-dependent, compartmentalized changes in immunity. Liver, adipose tissue, skeletal muscle, and immune cells communicate to relay metabolic and immune signals during fasting. Here we review the connections between metabolic and immune cells to explain the divergent effects of IF compared with classic caloric restriction (CR) strategies. We also explore how the immunometabolism of metabolic diseases dictates certain IF outcomes, where the gut microbiota triggers changes in immunity and metabolism during fasting.

Intermittent Fasting Regulates Metabolic Homeostasis and Improves Cardiovascular Health

Obesity is a leading cause of morbidity and mortality globally. While the prevalence of obesity has been increasing, the incidence of its related complications including dyslipidemia and cardiovascular disease (CVD) has also been rising. Recent research has focused on modalities aimed at reducing obesity. Several modalities have been suggested including behavioral and dietary changes, medications, and bariatric surgery. These modalities differ in their effectiveness and invasiveness, with dietary changes gaining more interest due to their minimal risks compared to other modalities. Specifically, intermittent fasting (IF) has been gaining interest in the past decade. IF is characterized by cycles of alternating fasting and eating windows, with several different forms practiced. IF has been shown to reduce weight and alleviate obesity-related complications. Our review of clinical and experimental studies explores the effects of IF on the lipid profile, white adipose tissue (WAT) dynamics, and the gut microbiome. Notably, IF corrects dyslipidemia, reduces WAT accumulation, and decreases inflammation, which reduces CVD and obesity. This comprehensive analysis details the protective metabolic role of IF, advocating for its integration into public health practices.

Adipose thermogenic mechanisms by cold, exercise and intermittent fasting: Similarities, disparities and the application in treatment

Given its nonnegligible role in metabolic homeostasis, adipose tissue has been the target for treating metabolic disorders such as obesity, diabetes and cardiovascular diseases. Besides its lipolytic function, adipose thermogenesis has gained increased interest due to the irreplaceable contribution to dissipating energy to restore equilibrium, and its therapeutic effects have been testified in various animal models. In this review, we will brief about the canonical cold-stimulated adipose thermogenic mechanisms, elucidate on the exercise- and intermittent fasting-induced adipose thermogenic mechanisms, with a focus on the similarities and disparities among these signaling pathways, in an effort to uncover the overlapped and specific targets that may yield potent therapeutic efficacy synergistically in improving metabolic health.

Motion-Accommodating Dual-Layer Hydrogel Dressing to Deliver Adipose-Derived Stem Cells to Wounds

BACKGROUND

Current dressing materials cannot secure a cell survival-promoting wound environment for stem cell delivery due to insufficient assimilation to skin motion. The authors developed a novel motion-accommodating dual-layer hydrogel dressing for stem cell delivery into such wounds.

METHODS

Dorsal hand skin movement was evaluated to determine the potential range of deformation for a dressing. The outer hydrogel (OH) was fabricated with an alginate-acrylamide double-network hydrogel with a covalently cross-linked elastomer coat. The tough adhesive consisted of a chitosan-based bridging polymer and coupling reagents. OH material properties and adhesiveness on porcine skin were measured. An oxidized alginate-based inner hydrogel (IH) containing human adipose-derived stem cells (ASCs) was evaluated for cell-supporting and cell-releasing properties. The OH's function as a secondary dressing, and dual-layer hydrogel cell delivery potential in wounds were assessed in a rodent model.

RESULTS

The dual-layer hydrogel consisted of OH and IH. The OH target range of deformation was up to 25% strain. The OH adhered to porcine skin, and showed significantly higher adhesion energy than common secondary dressings and endured 900 flexion-extension cycles without detachment. OH showed a similar moisture vapor transmission rate as moisture-retentive dressings. IH maintained embedded cell survival for three days with significant cell release on the contacting surface. OH showed less fibrotic wound healing than other secondary dressings in vivo. The dual-layer hydrogel successfully delivered ASCs into open wounds of nude mice (13 ± 3 cells/HPF).

CONCLUSIONS

The novel dual-layer hydrogel can accommodate patient movement and deliver ASCs into the wound bed by securing the wound microenvironment.

From fasting to fat reshaping: exploring the molecular pathways of intermittent fasting-induced adipose tissue remodeling

Obesity, characterised by excessive fat accumulation, is a complex chronic condition that results from dysfunctional adipose tissue expansion due to prolonged calorie surplus. This leads to rapid adipocyte enlargement that exceeds the support capacity of the surrounding neurovascular network, resulting in increased hypoxia, inflammation, and insulin resistance. Intermittent fasting (IF), a dietary regimen that cycles between periods of fasting and eating, has emerged as an effective strategy to combat obesity and improve metabolic homeostasis by promoting healthy adipose tissue remodeling. However, the precise molecular and cellular mechanisms behind the metabolic improvements and remodeling of white adipose tissue (WAT) driven by IF remain elusive. This review aims to summarise and discuss the relationship between IF and adipose tissue remodeling and explore the potential mechanisms through which IF induces alterations in WAT. This includes several key structural changes, including angiogenesis and sympathetic innervation of WAT. We will also discuss the involvement of key signalling pathways, such as PI3K, SIRT, mTOR, and AMPK, which potentially play a crucial role in IF-mediated metabolic adaptations.

Obstructive sleep apnea hypopnea syndrome and vascular lesions: An update on what we currently know

Obstructive sleep apnea-hypopnea syndrome (OSAHS) is the most prevalent sleep and respiratory disorder. This syndrome can induce severe cardiovascular and cerebrovascular complications, and intermittent hypoxia is a pivotal contributor to this damage. Vascular pathology is closely associated with the impairment of target organs, marking a focal point in current research. Vascular lesions are the fundamental pathophysiological basis of multiorgan ailments and indicate a shared pathogenic mechanism among common cardiovascular and cerebrovascular conditions, suggesting their importance as a public health concern. Increasing evidence shows a strong correlation between OSAHS and vascular lesions. Previous studies predominantly focused on the pathophysiological alterations in OSAHS itself, such as intermittent hypoxia and fragmented sleep, leading to vascular disruptions. This review aims to delve deeper into the vascular lesions affected by OSAHS by examining the microscopic pathophysiological mechanisms involved. Emphasis has been placed on examining how OSAHS induces vascular lesions through disruptions in the endothelial barrier, metabolic dysregulation, cellular phenotype alterations, neuroendocrine irregularities, programmed cell death, vascular inflammation, oxidative stress and epigenetic modifications. This review examines the epidemiology and associated risk factors for OSAHS and vascular diseases and subsequently describes the existing evidence on vascular lesions induced by OSAHS in the cardiovascular, cerebrovascular, retinal, renal and reproductive systems. A detailed account of the current research on the pathophysiological mechanisms mediating vascular lesions caused by OSAHS is provided, culminating in a discussion of research advancements in therapeutic modalities to mitigate OSAHS-related vascular lesions and the implications of these treatment strategies.

Alternate day fasting aggravates atherosclerosis through the suppression of hepatic ATF3 in Apoe-/- mice

Atherosclerosis is the major contributor to cardiovascular mortality worldwide. Alternate day fasting (ADF) has gained growing attention due to its metabolic benefits. However, the effects of ADF on atherosclerotic plaque formation remain inconsistent and controversial in atherosclerotic animal models. The present study was designed to investigate the effects of ADF on atherosclerosis in apolipoprotein E-deficient (Apoe -/- ) mice. Eleven-week-old male Apoe -/- mice fed with Western diet (WD) were randomly grouped into ad libitum (AL) group and ADF group, and ADF aggravated both the early and advanced atherosclerotic lesion formation, which might be due to the disturbed cholesterol profiles caused by ADF intervention. ADF significantly altered cholesterol metabolism pathways and down-regulated integrated stress response (ISR) in the liver. The hepatic expression of activating transcription factor 3 (ATF3) was suppressed in mice treated with ADF and hepatocyte-specific overexpression of Aft3 attenuated the effects of ADF on atherosclerotic plaque formation in Apoe -/- mice. Moreover, the expression of ATF3 could be regulated by Krüppel-like factor 6 (KLF6) and both the expressions of ATF3 and KLF6 were regulated by hepatic cellular ISR pathway. In conclusion, ADF aggravates atherosclerosis progression in Apoe -/- mice fed on WD. ADF inhibits the hepatic ISR signaling pathway and decreases the expression of KLF6, subsequently inhibiting ATF3 expression. The suppressed ATF3 expression in the liver mediates the deteriorated effects of ADF on atherosclerosis in Apoe -/- mice. The findings suggest the potentially harmful effects when ADF intervention is applied to the population at high risk of atherosclerosis.

Intermittent fasting promotes rejuvenation of immunosenescent phenotypes in aged adipose tissue

The aging of white adipose tissue (WAT) involves senescence of adipose stem and progenitor cells (ASPCs) and dysregulation of immune cell populations, serving as a major driver of age-associated adipose dysfunction and metabolic diseases. Conversely, the elimination of senescent ASPCs is associated with improvements in overall health. Intermittent fasting (IF), a dietary intervention that incorporates periodic cycles of fasting and refeeding, has been reported to promote weight loss and fat mass reduction and improve glucose and insulin homeostasis in both murine and human studies. While previous studies have assessed the effects of IF on obesity-associated metabolic dysfunction, few studies have examined the aging-specific changes to ASPCs and immune cell populations in WAT. Here, we show that IF in 18-20-month-old mice reduced senescent phenotypes of ASPCs and restored their adipogenic potential. Intriguingly, IF-treated mice exhibited an increase in adipose eosinophils, which has been reported to be associated with improved WAT homeostasis and immunological fitness in aged mice. The observed cellular and metabolic changes suggest that IF may be a feasible lifestyle regimen to reduce cellular senescence which could result in attenuation of downstream aging-induced WAT dysfunction and metabolic diseases.

Genetics, pharmacotherapy, and dietary interventions in childhood obesity

Childhood obesity has emerged as a major global health issue, contributing to the increased prevalence of chronic conditions and adversely affecting the quality of life and future prospects of affected individuals, thereby presenting a substantial societal challenge. This complex condition, influenced by the interplay of genetic predispositions and environmental factors, is characterized by excessive energy intake due to uncontrolled appetite regulation and a Westernized diet. Managing obesity in childhood requires specific considerations compared with adulthood, given the vulnerability of the critical juvenile-adolescent period to toxicity and developmental defects. Consequently, common treatment options for adult obesity may not directly apply to younger populations. Therefore, research on childhood obesity has focused on genetic defects in regulating energy intake, alongside pharmacotherapy and dietary interventions as management approaches, with an emphasis on safety concerns. This review aims to summarize canonical knowledge and recent findings on genetic factors contributing to childhood obesity. Additionally, it assesses the efficacy and safety of existing pharmacotherapies and dietary interventions and suggests future research directions. By providing a comprehensive understanding of the complex dynamics of childhood obesity, this review aims to offer insights into more targeted and effective strategies for addressing this condition, including personalized healthcare solutions.

Perivascular fat tissue and vascular aging: A sword and a shield

The understanding of the function of perivascular adipose tissue (PVAT) in vascular aging has significantly changed due to the increasing amount of information regarding its biology. Adipose tissue surrounding blood vessels is increasingly recognized as a key regulator of vascular disorders. It has significant endocrine and paracrine effects on the vasculature and is mediated by the production of a variety of bioactive chemicals. It also participates in a number of pathological regulatory processes, including oxidative stress, immunological inflammation, lipid metabolism, vasoconstriction, and dilation. Mechanisms of homeostasis and interactions between cells at the local level tightly regulate the function and secretory repertoire of PVAT, which can become dysregulated during vascular aging. The PVAT secretion group changes from being reducing inflammation and lowering cholesterol to increasing inflammation and increasing cholesterol in response to systemic or local inflammation and insulin resistance. In addition, the interaction between the PVAT and the vasculature is reciprocal, and the biological processes of PVAT are directly influenced by the pertinent indicators of vascular aging. The architectural and biological traits of PVAT, the molecular mechanism of crosstalk between PVAT and vascular aging, and the clinical correlation of vascular age-related disorders are all summarized in this review. In addition, this paper aims to elucidate and evaluate the potential benefits of therapeutically targeting PVAT in the context of mitigating vascular aging. Furthermore, it will discuss the latest advancements in technology used for targeting PVAT.

Intermittent fasting and longevity: From animal models to implication for humans

In recent years, intermittent fasting (IF) and its numerous modifications have been increasingly suggested as a promising therapy for age-related problems and a non-pharmacological strategy to extend lifespan. Despite the great variability in feeding schedules that we describe in the current work, underlying physiological processes are the same and include a periodic switch from glucose metabolism (generated by glycogenolysis) to fatty acids and fatty acid-derived ketones. Many of the beneficial effects of IF appear to be mediated by optimization of energy utilization. Findings to date from both human and animal experiments indicate that fasting improves physiological function, enhances performance, and slows aging and disease processes. In this review, we discuss some of the remarkable discoveries about the beneficial effects of IF on metabolism, endocrine and cardiovascular systems, cancer prevention, brain health, neurodegeneration and aging. Experimental studies on rodent models and human investigations are summarized to compare the outcomes and underlying mechanisms of IF. Metabolic and cellular responses triggered by IF could help to achieve the aim of preventing disease, and maximizing healthspan and longevity with minimal side effects.

Intermittent fasting promotes type 3 innate lymphoid cells secreting IL-22 contributing to the beigeing of white adipose tissue

Mechanism underlying the metabolic benefit of intermittent fasting remains largely unknown. Here, we reported that intermittent fasting promoted interleukin-22 (IL-22) production by type 3 innate lymphoid cells (ILC3s) and subsequent beigeing of subcutaneous white adipose tissue. Adoptive transfer of intestinal ILC3s increased beigeing of white adipose tissue in diet-induced-obese mice. Exogenous IL-22 significantly increased the beigeing of subcutaneous white adipose tissue. Deficiency of IL-22 receptor (IL-22R) attenuated the beigeing induced by intermittent fasting. Single-cell sequencing of sorted intestinal immune cells revealed that intermittent fasting increased aryl hydrocarbon receptor signaling in ILC3s. Analysis of cell-cell ligand receptor interactions indicated that intermittent fasting may stimulate the interaction of ILC3s with dendritic cells and macrophages. These results establish the role of intestinal ILC3s in beigeing of white adipose tissue, suggesting that ILC3/IL-22/IL-22R axis contributes to the metabolic benefit of intermittent fasting.

Caloric restriction for the immunometabolic control of human health

Nutrition affects all physiological processes occurring in our body, including those related to the function of the immune system; indeed, metabolism has been closely associated with the differentiation and activity of both innate and adaptive immune cells. While excessive energy intake and adiposity have been demonstrated to cause systemic inflammation, several clinical and experimental evidence show that calorie restriction (CR), not leading to malnutrition, is able to delay aging and exert potent anti-inflammatory effects in different pathological conditions. This review provides an overview of the ability of different CR-related nutritional strategies to control autoimmune, cardiovascular, and infectious diseases, as tested by preclinical studies and human clinical trials, with a specific focus on the immunological aspects of these interventions. In particular, we recapitulate the state of the art on the cellular and molecular mechanisms pertaining to immune cell metabolic rewiring, regulatory T cell expansion, and gut microbiota composition, which possibly underline the beneficial effects of CR. Although studies are still needed to fully evaluate the feasibility and efficacy of the nutritional intervention in clinical practice, the experimental observations discussed here suggest a relevant role of CR in lowering the inflammatory state in a plethora of different pathologies, thus representing a promising therapeutic strategy for the control of human health.

Adipocyte p53 coordinates the response to intermittent fasting by regulating adipose tissue immune cell landscape

In obesity, sustained adipose tissue (AT) inflammation constitutes a cellular memory that limits the effectiveness of weight loss interventions. Yet, the impact of fasting regimens on the regulation of AT immune infiltration is still elusive. Here we show that intermittent fasting (IF) exacerbates the lipid-associated macrophage (LAM) inflammatory phenotype of visceral AT in obese mice. Importantly, this increase in LAM abundance is strongly p53 dependent and partly mediated by p53-driven adipocyte apoptosis. Adipocyte-specific deletion of p53 prevents LAM accumulation during IF, increases the catabolic state of adipocytes, and enhances systemic metabolic flexibility and insulin sensitivity. Finally, in cohorts of obese/diabetic patients, we describe a p53 polymorphism that links to efficacy of a fasting-mimicking diet and that the expression of p53 and TREM2 in AT negatively correlates with maintaining weight loss after bariatric surgery. Overall, our results demonstrate that p53 signalling in adipocytes dictates LAM accumulation in AT under IF and modulates fasting effectiveness in mice and humans.

Alternate-day fasting ameliorated anxiety-like behavior in high-fat diet-induced obese mice

Alternate-day fasting (ADF) has been reported to reduce body weight, neuroinflammation, and oxidative stress damage. However, it is not known whether ADF affects obesity-induced anxiety-like behavior. Here, male C57BL/6 mice were given an alternate fasting and high-fat diet (HFD) or standard chow diet (SD) every other day for 16 or 5 weeks. After the intervention, the degree of anxiety of the mice was evaluated by the open field test (OFT) and the elevated plus maze (EPM) test. Pathological changes in the hippocampus, the expression of Sirt1 and its downstream protein monoamine oxidase A (MAO-A) in the hippocampus, and the expression of 5-hydroxytryptamine (5-HT) were detected. Compared with HFD-fed mice, HFD-fed mice subjected to ADF for 16 weeks had a lower body weight but more brown adipose tissue (BAT), less anxiety behavior, and less pathological damage in the hippocampus, and lower expression of Sirt1 and MAO-A protein and higher 5-HT levels in the hippocampus could be observed. In addition, we noted that long-term ADF intervention could cause anxiety-like behavior in SD mice. Next, we changed the intervention time to 5 weeks. The results showed that short-term ADF intervention could reduce the body weight and increase the BAT mass of SD mice, but it did not affect anxiety. These results indicated that long-term ADF ameliorated obesity-induced anxiety-like behavior and hippocampal damage, but caused anxiety in normal-weight mice. Short-term ADF did not produce adverse emotional reactions in normal-weight mice. Here, we might provide new ideas for the treatment of obesity-induced anxiety.

Intermittent fasting promotes ILC3s secreting IL-22 contributing to the beigeing of white adipose tissue

Mechanism underlying the metabolic benefit of intermittent fasting remains largely unknown. Here, we reported that intermittent fasting promoted IL-22 production by ILC3s and subsequent beigeing of subcutaneous white adipose tissue. Adoptive transfer of intestinal ILC3s increased beigeing of white adipose tissue in diet-induced-obese mice. Exogenous IL-22 significantly increased the beigeing of subcutaneous white adipose tissue. Deficiency of IL-22 receptor attenuated the beigeing induced by intermittent fasting. Single-cell sequencing of sorted intestinal immune cells revealed that intermittent fasting increased aryl hydrocarbon receptor signaling in ILC3s. Analysis of cell‒cell ligand receptor interactions indicated that intermittent fasting may stimulate the interaction of ILC3s with dendritic cells (DCs) and macrophages. These results establish the role of intestinal ILC3s in beigeing of white adipose tissue, suggesting that ILC3/IL-22/IL-22R axis contributes to the metabolic benefit of intermittent fasting.

Intermittent Fasting Reduces Neuroinflammation and Cognitive Impairment in High-Fat Diet-Fed Mice by Downregulating Lipocalin-2 and Galectin-3

Intermittent fasting (IF), an alternating pattern of dietary restriction, reduces obesity-induced insulin resistance and inflammation. However, the crosstalk between adipose tissue and the hippocampus in diabetic encephalopathy is not fully understood. Here, we investigated the protective effects of IF against neuroinflammation and cognitive impairment in high-fat diet(HFD)-fed mice. Histological analysis revealed that IF reduced crown-like structures and adipocyte apoptosis in the adipose tissue of HFD mice. In addition to circulating lipocalin-2 (LCN2) and galectin-3 (GAL3) levels, IF reduced HFD-induced increases in LCN2- and GAL3-positive macrophages in adipose tissue. IF also improved HFD-induced memory deficits by inhibiting blood-brain barrier breakdown and neuroinflammation. Furthermore, immunofluorescence showed that IF reduced HFD-induced astrocytic LCN2 and microglial GAL3 protein expression in the hippocampus of HFD mice. These findings indicate that HFD-induced adipocyte apoptosis and macrophage infiltration may play a critical role in glial activation and that IF reduces neuroinflammation and cognitive impairment by protecting against blood-brain barrier leakage.

Immune-regulatory properties of endovascular extravillous trophoblast cells in human placenta

INTRODUCTION

Uterine spiral artery remodeling is the prerequisite for ensuring adequate blood supply to the maternal-fetal interface during human pregnancy. One crucial cellular event in this process involves the extensive replacement of the spiral artery endothelial cells by endovascular extravillous trophoblasts (enEVTs), a subtype of extravillous trophoblasts (EVTs). However, our understanding of the properties of enEVTs remains limited.

METHODS

Human enEVTs in decidual tissues during early pregnancy was purified using flow sorting by specific makers, NCAM1 and HLA-G. The high-throughput RNA sequencing analysis as well as the cytokine antibody array experiments were carried out to analyze for cell properties. Gene ontology (GO) enrichment, kyoto encyclopedia of genes and genomes (KEGG) enrichment, and gene set enrichment analysis (GSEA) were performed on differentially expressed genes of enEVTs. Immunofluorescent assays were used to verify the analysis results.

RESULTS

Both enEVTs and interstitial EVTs (iEVTs) exhibited gene expression patterns typifying EVT characteristics. Intriguingly, enEVTs displayed gene expression associated with immune responses, particularly reminiscent of M2 macrophage characteristics. The active secretion of multiple cytokines and chemokines by enEVTs provided partial validation for their expression pattern of immune-regulatory genes.

DISCUSSION

Our study reveals the immune-regulatory properties of human enEVTs and provides new insights into their functions and mechanisms involved in spiral artery remodeling.

Modulating the polarization phenotype of microglia - A valuable strategy for central nervous system diseases

Central nervous system (CNS) diseases have become one of the leading causes of death in the global population. The pathogenesis of CNS diseases is complicated, so it is important to find the patterns of the disease to improve the treatment strategy. Microglia are considered to be a double-edged sword, playing both harmful and beneficial roles in CNS diseases. Therefore, it is crucial to understand the progression of the disease and the changes in the polar phenotype of microglia to provide guidance in the treatment of CNS diseases. Microglia activation may evolve into different phenotypes: M1 and M2 types. We focused on the roles that M1 and M2 microglia play in regulating intercellular dialogues, pathological reactions and specific diseases in CNS diseases. Importantly, we summarized the strategies used to modulate the polarization phenotype of microglia, including traditional pharmacological modulation, biological therapies, and physical strategies. This review will contribute to the development of potential strategies to modulate microglia polarization phenotypes and provide new alternative therapies for CNS diseases.

Intermittent Fasting Modulates Immune Response by Generating Tregs via TGF-β Dependent Mechanisms in Obese Mice with Allergic Contact Dermatitis

People with obesity maintain low levels of inflammation; therefore, their exposure to foreign antigens can trigger an excessive immune response. In people with obesity or allergic contact dermatitis (ACD), symptoms are exacerbated by a reduction in the number of regulatory T cells (Tregs) and IL-10/TGF-β-modified macrophages (M2 macrophages) at the inflammatory site. Benefits of intermittent fasting (IF) have been demonstrated for many diseases; however, the immune responses regulated by macrophages and CD4+T cells in obese ACD animal models are poorly understood. Therefore, we investigated whether IF suppresses inflammatory responses and upregulates the generation of Tregs and M2 macrophages in experimental ACD animal models of obese mice. The IF regimen relieved various ACD symptoms in inflamed and adipose tissues. We showed that the IF regimen upregulates Treg generation in a TGF-β-dependent manner and induces CD4+T cell hypo-responsiveness. IF-M2 macrophages, which strongly express TGF-β and inhibit CD4+T cell proliferation, directly regulated Treg differentiation from CD4+T cells. These results indicate that the IF regimen enhances the TGF-β-producing ability of M2 macrophages and that the development of Tregs keeps mice healthy against ACD exacerbated by obesity. Therefore, the IF regimen may ameliorate inflammatory immune disorders caused by obesity.

Effects of Calorie Restriction and Fasting on Macrophage: Potential Impact on Disease Outcomes?

Energy restriction, including calorie restriction and fasting, has garnered significant attention for its potential therapeutic effects on a range of chronic diseases (such as diabetes, obesity, and cancer) and aging. Since macrophages are critical players in many diseases, their response to energy restriction may impact disease outcomes. However, the diverse metabolic patterns and functions of macrophages can lead to variability in the effects of energy restriction on macrophages across different tissues and disease states. This review outlines the effects of energy restriction on macrophages in several diseases, offering valuable guidance for future studies and insights into the clinical applications of calorie restriction and fasting.

Effects and possible mechanisms of intermittent fasting on health and disease: a narrative review

The imbalance between energy intake and expenditure in an environment of continuous food availability can lead to metabolic disturbances in the body and increase the risk of obesity and a range of chronic noncommunicable diseases. Intermittent fasting (IF) is one of the most popular nonpharmacological interventions to combat obesity and chronic noncommunicable diseases. The 3 most widely studied IF regimens are alternate-day fasting, time-restricted feeding, and the 5:2 diet. In rodents, IF helps optimize energy metabolism, prevent obesity, promote brain health, improve immune and reproductive function, and delay aging. In humans, IF's benefits are relevant for the aging global population and for increasing human life expectancy. However, the optimal model of IF remains unclear. In this review, the possible mechanisms of IF are summarized and its possible drawbacks are discussed on the basis of the results of existing research, which provide a new idea for nonpharmaceutical dietary intervention of chronic noncommunicable diseases.

Aging, oxidative stress and degenerative diseases: mechanisms, complications and emerging therapeutic strategies

Aging accompanied by several age-related complications, is a multifaceted inevitable biological progression involving various genetic, environmental, and lifestyle factors. The major factor in this process is oxidative stress, caused by an abundance of reactive oxygen species (ROS) generated in the mitochondria and endoplasmic reticulum (ER). ROS and RNS pose a threat by disrupting signaling mechanisms and causing oxidative damage to cellular components. This oxidative stress affects both the ER and mitochondria, causing proteopathies (abnormal protein aggregation), initiation of unfolded protein response, mitochondrial dysfunction, abnormal cellular senescence, ultimately leading to inflammaging (chronic inflammation associated with aging) and, in rare cases, metastasis. RONS during oxidative stress dysregulate multiple metabolic pathways like NF-κB, MAPK, Nrf-2/Keap-1/ARE and PI3K/Akt which may lead to inappropriate cell death through apoptosis and necrosis. Inflammaging contributes to the development of inflammatory and degenerative diseases such as neurodegenerative diseases, diabetes, cardiovascular disease, chronic kidney disease, and retinopathy. The body's antioxidant systems, sirtuins, autophagy, apoptosis, and biogenesis play a role in maintaining homeostasis, but they have limitations and cannot achieve an ideal state of balance. Certain interventions, such as calorie restriction, intermittent fasting, dietary habits, and regular exercise, have shown beneficial effects in counteracting the aging process. In addition, interventions like senotherapy (targeting senescent cells) and sirtuin-activating compounds (STACs) enhance autophagy and apoptosis for efficient removal of damaged oxidative products and organelles. Further, STACs enhance biogenesis for the regeneration of required organelles to maintain homeostasis. This review article explores the various aspects of oxidative damage, the associated complications, and potential strategies to mitigate these effects.

An alternative approach to obesity treatment: intermittent fasting

Overweight and obesity are an important public health problem that affects a significant part of the world population and increases the risk of many metabolic diseases. Weight loss is the primary goal in obesity treatment, and many different dietary interventions are tried for this purpose. Intermittent fasting is a diet that has become popular in recent years with the weight loss it provides and includes periods of fasting and feeding. In addition to providing weight loss, intermittent fasting also has positive effects on important risk factors such as glucoregulatory parameters, blood lipids, and oxidative stress. Intermittent fasting appears to be an effective and safe way to achieve weight loss in obesity. It could also have therapeutic effects on obesity-related diseases. The aim of this review was to bring together up-to-date information on the effects of intermittent fasting on obesity and various obesity-related diseases, mechanisms of action, possible benefits and harms, and potential uses.

The Beneficial and Adverse Effects of Autophagic Response to Caloric Restriction and Fasting

Each cell is equipped with a conserved housekeeping mechanism, known as autophagy, to recycle exhausted materials and dispose of injured organelles via lysosomal degradation. Autophagy is an early-stage cellular response to stress stimuli in both physiological and pathological situations. It is thought that the promotion of autophagy flux prevents host cells from subsequent injuries by removing damaged organelles and misfolded proteins. As a correlate, the modulation of autophagy is suggested as a therapeutic approach in diverse pathological conditions. Accumulated evidence suggests that intermittent fasting or calorie restriction can lead to the induction of adaptive autophagy and increase longevity of eukaryotic cells. However, prolonged calorie restriction with excessive autophagy response is harmful and can stimulate a type II autophagic cell death. Despite the existence of a close relationship between calorie deprivation and autophagic response in different cell types, the precise molecular mechanisms associated with this phenomenon remain unclear. Here, we aimed to highlight the possible effects of prolonged and short-term calorie restriction on autophagic response and cell homeostasis.

Timing of energy intake and the therapeutic potential of intermittent fasting and time-restricted eating in NAFLD

Non-alcoholic fatty liver disease (NAFLD) represents a major public health concern and is associated with a substantial global burden of liver-related and cardiovascular-related morbidity and mortality. High total energy intake coupled with unhealthy consumption of ultra-processed foods and saturated fats have long been regarded as major dietary drivers of NAFLD. However, there is an accumulating body of evidence demonstrating that the timing of energy intake across a the day is also an important determinant of individual risk for NAFLD and associated metabolic conditions. This review summarises the available observational and epidemiological data describing associations between eating patterns and metabolic disease, including the negative effects of irregular meal patterns, skipping breakfast and night-time eating on liver health. We suggest that that these harmful behaviours deserve greater consideration in the risk stratification and management of patients with NAFLD particularly in a 24-hour society with continuous availability of food and with up to 20% of the population now engaged in shiftwork with mistimed eating patterns. We also draw on studies reporting the liver-specific impact of Ramadan, which represents a unique real-world opportunity to explore the physiological impact of fasting. By highlighting data from preclinical and pilot human studies, we present a further biological rationale for manipulating timing of energy intake to improve metabolic health and discuss how this may be mediated through restoration of natural circadian rhythms. Lastly, we comprehensively review the landscape of human trials of intermittent fasting and time-restricted eating in metabolic disease and offer a look to the future about how these dietary strategies may benefit patients with NAFLD and non-alcoholic steatohepatitis.

Dietary restriction induces a sexually dimorphic type I interferon response in mice with gene-environment interactions

Intermittent fasting (IF) is an established intervention to treat the growing obesity epidemic. However, the interaction between dietary interventions and sex remains a significant knowledge gap. In this study, we use unbiased proteome analysis to identify diet-sex interactions. We report sexual dimorphism in response to intermittent fasting within lipid and cholesterol metabolism and, unexpectedly, in type I interferon signaling, which was strongly induced in females. We verify that secretion of type I interferon is required for the IF response in females. Gonadectomy differentially alters the every-other-day fasting (EODF) response and demonstrates that sex hormone signaling can either suppress or enhance the interferon response to IF. IF fails to potentiate a stronger innate immune response when IF-treated animals were challenged with a viral mimetic. Lastly, the IF response changes with genotype and environment. These data reveal an interesting interaction between diet, sex, and the innate immune system.

A review of the role of intermittent fasting in the management of inflammatory bowel disease

Intermittent fasting (IF) may be a weight management strategy for patients with inflammatory bowel disease (IBD). The aim of this short narrative review is to summarize the evidence related to IF in the management of IBD. A literature search of English publications related to IF or time-restricted feeding and IBD, Crohn's disease, or ulcerative colitis was conducted in PubMed and Google Scholar. Four publications on studies of IF in IBD were found: three randomized controlled trials in animal models of colitis and one prospective observational study in patients with IBD. The results from animal studies suggest either moderate or no changes in weight but improvements in colitis with IF. These improvements may be mediated through changes in the gut microbiome, decreased oxidative stress and increased colonic short-chain fatty acids. The study in humans was small and uncontrolled, and it did not assess changes in weight, making it difficult to draw conclusions around the effects of IF on changes in weight or disease course. Given that preclinical evidence suggests intermittent fasting may play a beneficial role in IBD, randomized controlled trials in large patients with active disease are warranted to determine whether intermittent fasting could be an integrated therapy for patients with IBD management, either for weight or for disease management. These studies should also explore the potential mechanisms of action related to intermittent fasting.

Combined effects of intermittent fasting with swimming-based high intensity intermittent exercise training in Wistar rats

High caloric intake and physical inactivity are known precursors to the development of several chronic metabolic diseases. For obesity and sedentarism, High Intensity Intermittent Exercise (HIIE) and Intermittent Fasting (IF) have emerged as individual strategies to attenuate their negative effects by improving metabolism. To study their combined effects, Wistar male rats (n = 74, 60 days old) were divided into four groups: Sedentary Control (C), swimming-based HIIE only (HIIE), Intermittent Fasting only (IF), and swimming-based HIIE associated with Intermittent Fasting (HIIE/IF). Over an eight-week period swimming performance, body composition, weight and feeding behavior were analyzed. The final morphology of white adipose tissue showed a significant reduction in adipocyte size consistent with a higher number of cells per area in exercised animals (vs C and IF, p < 0.05), which also displayed characteristics of browning through UCP-1 levels and CD31 staining. These results suggest that the increased performance in the HIIE/IF group is, in part, by modifications of WAT metabolism through the browning process.