Monocytes re-enter the bone marrow during fasting and alter the host response to infection

Haematometabolism rewiring in atherosclerotic cardiovascular disease

Atherosclerotic cardiovascular diseases are the most frequent cause of death worldwide. The clinical complications of atherosclerosis are closely linked to the haematopoietic and immune systems, which maintain homeostatic functions and vital processes in the body. The nodes linking metabolism and inflammation are receiving increasing attention because they are inextricably linked to inflammatory manifestations of non-communicable diseases, including atherosclerosis. Although metabolism and inflammation are essential to survival and involve all tissues, we still know little about how these processes influence each other. In an effort to understand these mechanisms, in this Review we explore whether and how potent cardiovascular risk factors and metabolic modifiers of atherosclerosis influence the molecular and cellular machinery of 'haematometabolism' (metabolic-dependent haematopoietic stem cell skewing) and 'efferotabolism' (metabolic-dependent efferocyte reprogramming). These changes might ultimately propagate a quantitative and qualitative drift of the macrophage supply chain and affect the clinical manifestations of atherosclerosis. Refining our understanding of the different metabolic requirements of these processes could open the possibility of developing therapeutics targeting haematometabolism that, in conjunction with improved dietary habits, help rebalance and promote efficient haematopoiesis and efferocytosis and decrease the risk of atherosclerosis complications.

Neural Mechanisms in Cardiovascular Health and Disease

Although the neurocardiac axis is central to cardiovascular homeostasis, its dysregulation drives heart failure and cardiometabolic diseases. This review examines the bidirectional interplay between the autonomic nervous system and the heart, highlighting the role of this interplay in disease progression and its therapeutic potential. The autonomic nervous system modulates cardiac function and vascular tone through its sympathetic and parasympathetic branches. However, in heart failure, chronic sympathetic overdrive and parasympathetic withdrawal exacerbate myocardial remodeling and metabolic dysfunction, both of which are exacerbated by cardiometabolic conditions such as obesity and diabetes. These conditions are increasingly recognized to impair neurocardiac regulation, thereby promoting inflammation and adverse outcomes. An important emerging area concerns neuroimmune control, in which the brain orchestrates systemic inflammation through circuits involving the bone marrow, spleen, and other organs, thereby amplifying cardiovascular damage. This neuroimmune axis integrates peripheral signals to influence immune responses that contribute to disease progression. Lifestyle factors, such as stress, sleep, exercise, and diet, affect autonomic and immune balance and, thus, cardiovascular disease. Therapeutically, targeting neurocardiac and neuroimmune pathways pharmacologically or via neuromodulation (eg, vagal or splenic nerve stimulation) offers promise although the clinical translation of the latter remains challenging. In this review, we synthesize preclinical and clinical data to highlight the neurocardiac axis as a critical nexus in heart failure and cardiometabolic disease. Harnessing neuroimmune and neurocardiac interactions may inform precision approaches to reduce the burden of these conditions.

Intermittent time-restricted eating may increase autophagic flux in humans: an exploratory analysis

Autophagy slows age-related pathologies and is stimulated by nutrient restriction in animal studies. However, this has never been shown in humans. We measured autophagy using a physiologically relevant measure of autophagic flux (flux of MAP1LC3B isoform II/LC3B-II in peripheral blood mononuclear cells in the context of whole blood) in 121 humans with obesity who were randomised to standard care (SC, control condition), calorie restriction (CR) or intermittent fasting plus time-restricted eating (iTRE) for 6 months. While the differences in change from baseline between groups was not significant at 2 months, we observed a significant difference in change from baseline between iTRE compared to SC at 6 months (P = 0.04, post hoc analysis). This effect may be driven partly by a tendency for autophagy to decrease in the SC group. The difference in change from baseline between CR and SC was not significant. Uncorrected analysis of correlations showed a negative relationship between change in autophagy and change in blood triglycerides. Data on the specificity and performance of the methods used to measure human autophagy are also presented. This shows autophagy may be increased by intermittent nutrient restriction in humans. If so, this is a demonstration that nutrient restriction can be used to improve a primary hallmark of biological ageing and provides a mechanism for how fasting could delay the onset of age-related disease. KEY POINTS: Autophagy slows biological ageing, and dysfunction of autophagy has been implicated in age-related disease - an effective way of increasing autophagy in cells and animal models is nutrient restriction. However, the impact of different types of nutrient restriction on physiological autophagic flux in humans has not been extensively researched. Here we measure the effect of intermittent time-restricted eating (iTRE) and calorie restriction on physiological autophagic flux in peripheral blood mononuclear cells. After 6 months, there was a significant difference in change from baseline between the iTRE and the standard care control group, with flux being higher in the iTRE group at this timepoint. However, there was no significant increase from baseline within the iTRE group, showing that although autophagy may be modified by nutrient restriction in humans, further studies are required.

Exploring the Impact of Intermittent Fasting on Vascular Function and the Immune System: A Narrative Review and Novel Perspective

Vascular function is a critical determinant of cardiovascular health and all-cause mortality. Recent studies have suggested that intermittent fasting, a popular dietary strategy, elicits beneficial effects on vascular function. These studies also suggest that fasting-mediated improvements in vascular function coincide with reductions in systemic inflammation. However, the mechanisms that connect fasting, the immune system, and vascular function remain largely underexplored. The current review summarizes the effects of different intermittent fasting modalities on vascular health, focusing on endothelial dysfunction and arterial stiffness, 2 critical indices of vascular function. Improvements in vascular function are associated with reduced inflammation and are mechanistically linked to decreased circulating immune cells and their accumulation within the vascular wall and perivascular tissue. Recent data show that fasting redistributes circulating and tissue-resident immune cells to the bone marrow, affecting their inflammatory actions. However, there is no direct evidence relating immune cell redistribution to cardiovascular health. By relating fasting-induced immune cell redistribution to reduced inflammation and improved vascular function, we propose an exciting avenue of further exploration is determining whether fasting-induced immune cell redistribution impacts cardiovascular health.

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.

Sympathetic activation of white adipose tissue recruits neutrophils to limit energy expenditure

Adipose tissue maintains energy homeostasis by storing lipids during nutrient surplus and releasing them through lipolysis in times of energy demand. While lipolysis is essential for short term metabolic adaptation, prolonged metabolic stress requires adaptive changes that preserve energy reserves. Here, we report that β-adrenergic activation of adipocytes induces a transient and depot-specific infiltration of neutrophils into white adipose tissue (WAT), particularly in lipid-rich visceral WAT. Neutrophil recruitment requires the stimulation of both lipolysis and p38 MAPK activation in adipocytes. Recruited neutrophils locally secrete IL-1β, which suppresses lipolysis and limits excessive energy expenditure. Neutrophil depletion or blockade of IL-1β production increased lipolysis, leading to reduced WAT mass upon repeated β3-adrenergic stimulation. Together, these findings reveal an unexpected role of neutrophil-derived IL-1β in preserving lipid stores during metabolic stress, highlighting a physiological function of innate immune cells in maintaining energy homeostasis.

Integrating cancer medicine into metabolic rhythms

Circadian rhythms are cell-intrinsic time-keeping mechanisms that allow organisms to adapt to 24-h environmental changes, ensuring coordinated physiological functions by aligning internal metabolic oscillations with external timing cues. Disruption of daily metabolic rhythms is associated with pathological events such as cancer development, yet the mechanisms by which perturbed metabolic rhythms contribute to tumorigenesis remain unclear. Herein we review how circadian clocks drive balanced rhythmic metabolism which in turn governs physiological functions of locomotor, immune, and neuroendocrine systems. Misaligned metabolic rhythms cause pathological states which further drive cancer initiation, progression, and metastasis. Restoring the balance of metabolic rhythms with chemical, hormonal, and behavioral interventions serves as a promising strategy for cancer therapy.

Brain sensing of metabolic state regulates circulating monocytes

Changes in energy availability alter the dynamics of circulating immune cells. The existing view is that these effects are due to altered nutrient levels affecting peripheral tissue metabolism. Here, using mice and genetic approaches to manipulate the activity of distinct molecularly defined neurons, we show that the brain's perception of hunger and satiety alone is sufficient to drive these immune changes. Hunger-promoting Agouti-related peptide (AgRP) neurons in the hypothalamus were both sufficient and necessary to reduce circulating Ly6CHi classical monocytes during fasting. Mechanistically, these neurons suppressed hepatic mammalian target of rapamycin signaling via sympathetic regulation, decreasing circulating chemokine ligand 2 and monocyte numbers. AgRP neuron-induced corticosterone release and glucocorticoid receptor activation played a permissive role in this process. These changes in monocyte dynamics can occur independently of actual nutrient levels, revealing an unexpected brain-mediated control of peripheral immunity in response to perceived variation in energy state.

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.

RUNX2 promotes fibrosis via an alveolar-to-pathological fibroblast transition

A hallmark of pulmonary fibrosis is the aberrant activation of lung fibroblasts into pathological fibroblasts that produce excessive extracellular matrix1-3. Thus, the identification of key regulators that promote the generation of pathological fibroblasts can inform the development of effective countermeasures against disease progression. Here we use two mouse models of pulmonary fibrosis to show that LEPR+ fibroblasts that arise during alveologenesis include SCUBE2+ alveolar fibroblasts as a major constituent. These alveolar fibroblasts in turn contribute substantially to CTHRC1+POSTN+ pathological fibroblasts. Genetic ablation of POSTN+ pathological fibroblasts attenuates fibrosis. Comprehensive analyses of scRNA-seq and scATAC-seq data reveal that RUNX2 is a key regulator of the expression of fibrotic genes. Consistently, conditional deletion of Runx2 with LeprcreERT2 or Scube2creERT2 reduces the generation of pathological fibroblasts, extracellular matrix deposition and pulmonary fibrosis. Therefore, LEPR+ cells that include SCUBE2+ alveolar fibroblasts are a key source of pathological fibroblasts, and targeting Runx2 provides a potential treatment option for pulmonary fibrosis.

Changes in plasma cytokines following a 60-h fast are not influenced by the addition of exercise despite elevated ketones in healthy young adults

Immunometabolic processes maintain physiological homeostasis and are implicated in various chronic diseases. Fasting and exercise independently alter metabolic and immunological processes; their combination could provide insights into immunometabolic interactions. Using a randomized crossover design, 15 healthy adults (six females, nine males, 26.5 ± 4.3 years) fasted for 60 h with and without the addition of a 3 h cycling bout (65%-80% VO2 peak). Fasting alone (FAST) and with exercise (FEX) reduced plasma glucose, insulin, respiratory exchange ratio, and increased β-hydroxybutyrate (BHB; all p < 0.01). FEX elicited more rapid changes in glucose and BHB and higher BHB concentrations at 60 h (all p < 0.01). Both conditions decreased circulating TNF-⍺ concentrations and increased IL-10 (p < 0.01), although the increase in IL-10 appeared to be driven by the FEX condition (p = 0.03). IL-6 concentrations tended to increase in both conditions (p = 0.1). Total white blood cell count remained unchanged after 60 h in both conditions, with only modest changes in some leukocyte subpopulations. Collectively, the observed changes in circulating cytokine concentrations support an overall anti-inflammatory effect of prolonged fasting, while the maintenance of leukocyte concentrations suggests immune function is not compromised. Despite greater metabolic strain, the addition of prolonged exercise did not appear to augment changes in systemic cytokines and leukocytes.

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.

Central nervous system and immune cells interactions in cancer: unveiling new therapeutic avenues

Cancer remains a leading cause of mortality worldwide. Despite significant advancements in cancer research, our understanding of its complex developmental pathways remains inadequate. Recent research has clarified the intricate relationship between the central nervous system (CNS) and cancer, particularly how the CNS influences tumor growth and metastasis via regulating immune cell activity. The interactions between the central nervous system and immune cells regulate the tumor microenvironment via various signaling pathways, cytokines, neuropeptides, and neurotransmitters, while also incorporating processes that alter the tumor immunological landscape. Furthermore, therapeutic strategies targeting neuro-immune cell interactions, such as immune checkpoint inhibitors, alongside advanced technologies like brain-computer interfaces and nanodelivery systems, exhibit promise in improving treatment efficacy. This complex bidirectional regulatory network significantly affects tumor development, metastasis, patient immune status, and therapy responses. Therefore, understanding the mechanisms regulating CNS-immune cell interactions is crucial for developing innovative therapeutic strategies. This work consolidates advancements in CNS-immune cell interactions, evaluates their potential in cancer treatment strategies, and provides innovative insights for future research and therapeutic approaches.

Integrated control of leukocyte compartments as a feature of adaptive physiology

As a highly diverse and mobile organ, the immune system is uniquely equipped to participate in tissue responses in a tunable manner, depending on the number, type, and nature of cells deployed to the respective organ. Most acute organismal stressors that threaten survival-predation, infection, poisoning, and others-induce pronounced redistribution of immune cells across tissue compartments. Here, we review the current understanding of leukocyte compartmentalization under homeostatic and noxious conditions. We argue that leukocyte shuttling between compartments is a function of local tissue demands, which are linked to the organ's contribution to adaptive physiology at steady state and upon challenge. We highlight the neuroendocrine signals that relay and organize this trafficking behavior and outline mechanisms underlying the functional diversification of leukocyte responses. In this context, we discuss important areas of future inquiry and the implications of this scientific space for clinical medicine in the era of targeted immunomodulation.

Intermittent Fasting Reduces Intestinal Inflammation in Dextran Sulfate Sodium-Induced Colitis of Mice

Inflammatory bowel disease (IBD), comprising ulcerative colitis (UC) and Crohn's disease (CD), is a chronic condition impacting both the gastrointestinal tract and the immune system. Intestinal inflammation and epithelial injury are the pathological features of IBD. Recent studies have reported that some strategies of dietary restriction (DR) can regulate immune system, correct the immune disorders, and improve some immune-associated diseases such as IBD. However, as a form of DR, the effect of intermittent fasting (IF) on the IBD remains unknown. In this study, we investigated the therapeutic efficacy of two cycles of IF on the IBD mouse model induced by dextran sulfate sodium (DSS). It was found that two cycles of IF significantly decreased the score of the disease activity index (DAI) and alleviated the IBD-related symptoms. In addition, IF reversed the shortening of colon length mediated by DSS, significantly increased the number of colonic crypts, and decreased the colonic histological score. Furthermore, the proportion of CD4+ T cells in both the spleen and mesenteric lymph node was reduced by IF treatment. The expression of serum pro-inflammatory cytokines IL-1β, TNF-α, and IL-6 was restrained by IF intervention. Moreover, IF administration significantly reduced the number of leukocytes and macrophages infiltrating around the crypt base in the colon. In conclusion, these results demonstrated that IF administration can alleviate the symptoms and pathology of IBD in the DSS-induced IBD mouse model by reducing the intestinal inflammation.

Caloric Restriction Preserves BBB Integrity After Transient Focal Cerebral Ischemia Through Reducing Neutrophil Infiltration

AIMS

Caloric restriction is a health-promoting lifestyle that has been reported to protect both white and gray matter in cases of ischemic stroke. This study will explore the underlying mechanism of restricted feeding (RF) and provide a theoretical basis for precise clinical treatment of stroke.

METHODS

In this study, we pretreated C57BL/6J mice with 70% RF for a continuous 28-day period prior to 60 min of transient focal cerebral ischemia (tFCI). Histological staining, diffusion tensor imaging (DTI), and behavioral assessments were used to assess RF's neuroprotection following tFCI. Immunofluorescence staining, quantitative real-time PCR, and flow cytometry were conducted to evaluate brain inflammation post-tFCI. Western blot, immunofluorescence staining, tracers, and electric microscopy were used to assess the blood-brain barrier (BBB) integrity. Peripheral neutrophils were cleared by administrating an anti-Ly6G antibody.

RESULTS

Initially, DTI, NeuN staining, and a batch of behavioral tests verified that RF significantly mitigated both gray/white matter injury and neurological deficits in the short- and long-term following tFCI. RF mice showed more anti-inflammatory microglia in their brains, along with reduced inflammatory cytokines, and chemokines. Interestingly, RF significantly reduced the neutrophils and macrophage infiltration. Subsequently, we observed that RF mice exhibited better BBB integrity following tFCI, with reduced neutrophil infiltration and matrix metalloprotein-9 release. Furthermore, the clearance of neutrophils with anti-Ly6G antibody in ad libitum feeding mice (LF-Ly6G) elicited comparable neuroprotective effects to those observed in RF, including improvements in neurological deficits, reductions in infarct volume, and mitigation of BBB damage.

CONCLUSIONS

In summary, our findings suggest that RF maintains the BBB integrity following ischemic stroke at least partially by reducing neutrophil infiltration, thereby alleviating both neurological and histological impairments.

Gut Microbiota: An Important Participant in Childhood Obesity

Increasing prevalence of childhood obesity has emerged as a critical global public health concern. Recent studies have challenged the previous belief that obesity was solely a result of excessive caloric intake. Alterations in early-life gut microbiota can contribute to childhood obesity through their influence on nutrient absorption and metabolism, initiation of inflammatory responses, and regulation of gut-brain communication. The gut microbiota is increasingly acknowledged to play a crucial role in human health, as certain beneficial bacteria have been scientifically proven to possess the capacity to reduce body fat content and enhance intestinal barrier function and their metabolic products to exhibit anti-inflammatory effect. Examples of such microbes include bifidobacteria, Akkermansia muciniphila, and Lactobacillus reuteri. In contrast, an increase in Enterobacteriaceae and propionate-producing bacteria (Prevotellaceae and Veillonellaceae) has been implicated in the induction of low-grade systemic inflammation and disturbances in lipid metabolism, which can predispose individuals to obesity. Studies have demonstrated that modulating the gut microbiota through diet, lifestyle changes, prebiotics, probiotics, or fecal microbiota transplantation may contribute to gut homeostasis and the management of obesity and its associated comorbidities. This review aimed to elucidate the impact of alterations in gut microbiota composition during early life on childhood obesity and explores the mechanisms by which gut microbiota contributes to the pathogenesis of obesity and specifically focused on recent advances in using short-chain fatty acids for regulating gut microbiota and ameliorating obesity. Additionally, it aimed to discuss the therapeutic strategies for childhood obesity from the perspective of gut microbiota, aiming to provide a theoretical foundation for interventions targeting pediatric obesity based on gut microbiota.

Unraveling the peripheral nervous System's role in tumor: A Double-edged Sword

The peripheral nervous system (PNS) includes all nerves outside the brain and spinal cord, comprising various cells like neurons and glial cells, such as schwann and satellite cells. The PNS is increasingly recognized for its bidirectional interactions with tumors, exhibiting both pro- and anti-tumor effects. Our review delves into the complex mechanisms underlying these interactions, highlighting recent findings that challenge the conventional understanding of PNS's role in tumorigenesis. We emphasize the contradictory results in the literature and propose novel perspectives on how these discrepancies can be resolved. By focusing on the PNS's influence on tumor initiation, progression, and microenvironment remodeling, we provide a comprehensive analysis that goes beyond the structural description of the PNS. Our review suggests that a deeper comprehension of the PNS-tumor crosstalk is pivotal for developing targeted anticancer strategies. We conclude by emphasizing the need for future research to unravel the intricate dynamics of the PNS in cancer, which may lead to innovative diagnostic tools and therapeutic approaches.

Fasting: A Complex, Double-Edged Blade in the Battle Against Doxorubicin-Induced Cardiotoxicity

In recent years, there has been a surge in the popularity of fasting as a method to enhance one's health and overall well-being. Fasting is a customary practice characterized by voluntary refraining from consuming food and beverages for a specified duration, ranging from a few hours to several days. The potential advantages of fasting, including enhanced insulin sensitivity, decreased inflammation, and better cellular repair mechanisms, have been well documented. However, the effects of fasting on cancer therapy have been the focus of recent scholarly investigations. Doxorubicin (Dox) is one of the most widely used chemotherapy medications for cancer treatment. Unfortunately, cardiotoxicity, which may lead to heart failure and other cardiovascular issues, has been linked to Dox usage. This study aims to comprehensively examine the possible advantages and disadvantages of fasting concerning Dox-induced cardiotoxicity. Researchers have investigated the potential benefits of fasting in lowering the risk of Dox-induced cardiac damage to solve this problem. Nevertheless, new studies indicate that prolonged alternate-day fasting may adversely affect the heart's capacity to manage the cardiotoxic properties of Dox. Though fasting may benefit overall health, it is essential to proceed cautiously and consider the potential risks in certain circumstances.

Promoting application of enhanced recovery after surgery protocols during perioperative localized abdominal and thoracic neuroblastomas

AIM

To investigate the safety and efficacy of the application of enhanced recovery after surgery (ERAS) protocols in the perioperative period of abdominal and thoracic localized neuroblastomas (NBs).

METHODS

In this retrospective study, 68 children with NBs who underwent surgical resection of the tumor were enrolled. The ERAS protocols for NB excision were implemented in the ERAS group (n = 39) and the consequences were compared with children treated with traditional care (n = 29, TRAD group). The main outcomes of our interest included the incidence of surgery-related complications, the postoperative length of stay (LOS), and the Face/Legs/Activity/Cry/Consolability (FLACC) quantitative table from postoperative days (POD) 1-5. We also evaluated the median intraoperative fluid volume and anesthesia recovery time; blood glucose levels at the beginning of anesthesia, POD1, and 3; WBC counts, CRP values, and the concentration of plasma nutritional indicators on POD1 and 3; time of early ambulation, first anal exhaust, total enteral nutrition (TEN), and discontinue intravenous infusion postoperatively; usage proportion and duration of abdominal and thoracic drainages, nasogastric decompression tubes and urinary catheters; cost of hospitalization, parental satisfaction rate, and readmission rate of surgery ward within 30 days.

RESULTS

Compared to the TRAD group, the ERAS group had lower surgery-related complications, albeit not significantly (P > 0.05); the median postoperative LOS decreased from 11.0 to 8.0 days (P < 0.001), the LOS of abdominal NB was significantly shortened (P < 0.001) compared to thoracic NB (P = 0.07) between the two groups; the FLACC scores decreased significantly from POD1-5 (all P < 0.01). The ERAS group had an improved median intraoperative infusion speed (5.0 mL/kg/h vs 8.0 mL/kg/h), time of early ambulation (1.0 days vs 3.0 days), first anal exhaust (2.0 days vs 2.0 days), TEN (5.0 vs 7.0 days), discontinuation of intravenous infusion (5.0 days vs 8.0 days), and total cost of hospitalization (33,897.2 Yuan vs 38,876.3 Yuan); (all P < 0.01). The usage proportion and duration of surgical drainages and tubes were apparently reduced. The mean blood glucose level was higher at the beginning of anesthesia but lower on POD1 and 3 in the ERAS group (P < 0.01). No statistically significant difference was detected in WBC counts and concentrations of hemoglobin and albumin between the two groups of patients (P > 0.05), while the concentrations of prealbumin on POD3 were higher and the CRP level on POD1 was lower in the ERAS group than the TRAD group (P < 0.01). The satisfaction rate of parents was only slightly higher, but the difference was not statistically significant (P = 0.730). No obvious differences were observed in the aspects of NB resection (P = 0.462) and 30-day readmissions of surgery ward (P = 1.000).

CONCLUSION

The application of ERAS protocols has a significant potential to accelerate perioperative rehabilitation in children undergoing abdominal and thoracic NBs' surgical resection.

Glucose metabolism controls monocyte homeostasis and migration but has no impact on atherosclerosis development in mice

Monocytes directly contribute to atherosclerosis development by their recruitment to plaques in which they differentiate into macrophages. In the present study, we ask how modulating monocyte glucose metabolism could affect their homeostasis and their impact on atherosclerosis. Here we investigate how circulating metabolites control monocyte behavior in blood, bone marrow and peripheral tissues of mice. We find that serum glucose concentrations correlate with monocyte numbers. In diet-restricted mice, monocytes fail to metabolically reprogram from glycolysis to fatty acid oxidation, leading to reduced monocyte numbers in the blood. Mechanistically, Glut1-dependent glucose metabolism helps maintain CD115 membrane expression on monocytes and their progenitors, and regulates monocyte migratory capacity by modulating CCR2 expression. Results from genetic models and pharmacological inhibitors further depict the relative contribution of different metabolic pathways to the regulation of CD115 and CCR2 expression. Meanwhile, Glut1 inhibition does not impact atherosclerotic plaque development in mouse models despite dramatically reducing blood monocyte numbers, potentially due to the remaining monocytes having increased migratory capacity. Together, these data emphasize the role of glucose uptake and intracellular glucose metabolism in controlling monocyte homeostasis and functions.

Effect of ketogenic diets on insulin-like growth factor (IGF)-1 in humans: A systematic review and meta-analysis

BACKGROUND

Insulin-like growth factor (IGF)-1 plays a role in aging and cancer biology, with fasting known to reduce serum IGF-1 levels in human adults. However, the impact of ad libitum ketogenic diets (KDs) on IGF-1 levels remains unclear.

METHODS

Adhering to PRISMA guidelines, we conducted a meta-analysis of human trials by systematically searching Ovid, PubMed, Scopus, and CENTRAL Libraries until June 2023. Eligible studies prescribed KDs to adults of any health status, confirmed ketosis, and measured serum IGF-1. Protocols involving prescribed fasting or energy restriction were excluded. Mean differences (MD) and 95 % confidence intervals (CIs) were calculated longitudinally between pre- and post-intervention measurements for the KD groups.

RESULTS

Among twelve publications meeting the inclusion criteria, 522 individuals participated, with 236 completing KDs. The intervention duration ranged from 1 to 20 weeks. Pooled results from ten trials showed a significant reduction in serum IGF-1 levels post-intervention (MD: -24.9 ng/mL [95 % CI -31.7 to -18.1]; p<0.0001) with low heterogeneity across studies (I2=27 %, p=0.19). KDs were also associated with significantly decreased fasting insulin (MD: -2.57 mU/L [95 % CI -4.41 to -0.74], p=0.006) and glucose (MD: -7.30 mg/dL [95 % CI -11.62 to -2.98], p=0.0009), although heterogeneity was significant. Subgroup analyses on study design, gender, dietary duration, and oncological status revealed no significant differences.

CONCLUSION

Ad libitum KDs (>55 % fat) effectively induce ketosis and can lower serum IGF-1 by 20 %, fasting glucose by 6 % and insulin by 29 %. This clinically notable reduction in IGF-1 can be attained without the need for a prescribed fasting or severe calorie restriction regimen. Further investigation is warranted to explore the impact of KDs on ageing biomarkers and cancer management.

The indispensability of methyltransferase-like 3 in the immune system: from maintaining homeostasis to driving function

Methyltransferase-like 3(METTL3), recognized as the primary N6-methyladenosine methyltransferase, influences cellular functions such as proliferation, migration, invasion, differentiation, and fate determination by regulating gene expression post-transcriptionally. Recent studies have highlighted the indispensability of METTL3 in various immune cells such as hematopoietic stem/progenitor cells, innate immune cells (monocytes, macrophages, dendritic cells), and adaptive immune cells (thymic epithelial cell, T cells, natural killer cells). However, a comprehensive summary and analysis of these findings to elucidate the relationship between METTL3 and the immune system is yet to be undertaken. Therefore, in this review, we systematically collate reports detailing the mechanism underlying the role of METTL3 in regulating various immune processes and examine the modification of METTL3 and its potential implications. This review suggests that METTL3 plays an essential role in the immune system, ranging from maintaining homeostasis to regulating functions. Collectively, this review provides a comprehensive analysis of the relationship between METTL3 and the immune system, serving convenient researchers to understand the frontiers of immunological research and facilitate future clinical applications.

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.

Comparing caloric restriction regimens for effective weight management in adults: a systematic review and network meta-analysis

BACKGROUND

Randomized controlled trials have confirmed the effectiveness of four prevalent caloric restriction regimens in reducing obesity-related health risks. However, there is no consensus on the optimal regimen for weight management in adults.

METHODS

We systematically searched PubMed, Embase, Web of Science, and Cochrane CENTRAL up to January 15, 2024, for randomized controlled trials (RCT) involving adults, evaluating the weight-loss effects of alternate day fasting (ADF), short-term fasting (STF), time-restricted eating (TRE), and continuous energy restriction (CER). The primary outcome was body weight, with secondary outcomes including BMI, fat mass, lean mass, waist circumference, fasting glucose, HOMA-IR, and adverse events. Bayesian network meta-analysis was conducted, ranking regimens using the surface under the cumulative ranking curve and the probability of being the best. Study quality was assessed using the Confidence in Network Meta-Analysis tool.

RESULTS

Data from 47 RCTs (representing 3363 participants) were included. ADF showed the most significant body weight loss (Mean difference (MD): -3.42; 95% Confidence interval (CI): -4.28 to -2.55), followed by TRE (MD: -2.25; 95% CI: -2.92 to -1.59). STF (MD: -1.87; 95% CI: -3.32 to -0.56) and CER (MD: -1.59; 95% CI: -2.42 to -0.79) rank third and fourth, respectively. STF lead to decline in lean mass (MD: -1.26; 95% CI: -2.16, -0.47). TRE showed benefits on fasting glucose (MD: -2.98; 95% CI: -4.7, -1.26). Subgroup analysis revealed all four caloric restriction regimens likely lead to modest weight loss after 1-3 months, with ADF ranked highest, but by 4-6 months, varying degrees of weight regain occur, particularly with CER, while interventions lasting 7-12 months may result in effective weight loss, with TRE potentially ranking first during both the 4-6 months and 7-12 months periods. ADF showing fewer and shorter-lasting physical symptoms.

CONCLUSION

All four included regiments were effective in reducing body weight, with ADF likely having the most significant impact. Each regimen likely leads to modest weight loss after 1-3 months, followed by weight regain by 4-6 months. However, interventions lasting 7-12 months achieve greater weight loss overall.

TRIAL REGISTRATION

PROSPERO: CRD42022382478.

Caloric restriction impacts skin barrier function and attenuates the development of hyperplasia skin disease

Caloric restriction (CR) stands out as one of the most potent interventions that prolong lifespan and mitigate age-associated diseases. Despite its well-established systemic effects, the impact of CR on skin physiological function remains poorly understood, and whether the intervention can alleviate the progression of inflammatory skin diseases remains uncertain. Here, we investigated the effects of CR on mouse skin barrier function and inflammatory response. Our results revealed that CR led to dramatic atrophy in the skin subcutaneous layer. The expression of barrier proteins and trans-epidermal water loss remain largely unchanged. Intriguingly, skin from CR mice exhibited reduced expression of inflammatory cytokines under steady conditions. In an imiquimod (IMQ)-induced mouse model of psoriasis, CR treatment attenuated the pathogenesis of psoriasis phenotypes, accompanied by a reduced activation of mTOR signaling in the psoriatic skin. Taken together, our findings shed light on the complex interplay between metabolic interventions and skin health, suggesting that CR has the potential to serve as a modulator of inflammatory responses in the skin.

Associations of daily eating frequency and nighttime fasting duration with biological aging in National Health and Nutrition Examination Survey (NHANES) 2003-2010 and 2015-2018

BACKGROUND

Information on the influences of daily eating frequency (DEF) and nighttime fasting duration (NFD) on biological aging is minimal. Our study investigated the potential associations of DEF and NFD with accelerated aging.

METHODS

Out of 24212 participants in NHANES 2003-2010 and 2015-2018, 4 predicted age metrics [homeostatic dysregulation (HD), Klemera-Doubal method (KDM), phenoAge (PA), and allostatic load (AL)] were computed based on 12 blood chemistry parameters. Utilizing 24-h dietary recall, DEF was measured by the frequency of eating occurrences, while NFD was determined by assessing the timing of the initial and final meals throughout the day. Weighted multivariate linear regression models and restricted cubic spline (RCS) were utilized to examine the associations.

RESULTS

Compared to DEF of ≤ 3.0 times, subjects with DEF ≥ 4.6 times demonstrated lower KDM residual [β: -0.57, 95% confidence-interval (CI): (-0.97, -0.17)] and PA residual [β: -0.47, 95% CI: (-0.69, -0.25)]. In comparison to NFD between 10.1 and 12.0 h, individuals with NFD ≤ 10.0 h were at higher HD [β: 0.03, 95% CI: (0.01, 0.04)], KDM residual [β: 0.34, 95% CI: (0.05, 0.63)], and PA residual [β: 0.38, 95% CI: (0.18, 0.57)]. Likewise, those with NFD ≥ 14.1 h also had higher HD [β: 0.02, 95% CI: (0.01, 0.04)] and KDM residual [β: 0.33, 95% CI: (0.03, 0.62)]. The results were confirmed by the dose-response relationships of DEF and NFD with predicted age metrics. Lactate dehydrogenase (LDH) and globulin (Glo) were acknowledged as implicated in and mediating the relationships.

CONCLUSIONS

DEF below 3.0 times and NFD less than 10.0 or more than 14.1 h were independently associated with higher predicted age metrics.

Fasting alleviates bleomycin-induced lung inflammation and fibrosis via decreased Tregs and monocytes

PURPOSE

Idiopathic pulmonary fibrosis (IPF), a chronic and progressively worsening condition characterized by interstitial lung inflammation and fibrosis of unknown etiology, has a grim prognosis. The treatment options for IPF are limited and new therapeutic strategies are urgently needed. Dietary restriction can improve various inflammatory diseases, but its therapeutic effect on bleomycin (BLM)-induced pulmonary fibrosis mouse model remains unclear. This study aims to investigate whether intermittent fasting (IF) can alleviate BLM-induced pulmonary inflammation and fibrosis.

METHODS

Pulmonary fibrosis mouse models were induced by BLM. The IF group underwent 24-h fasting cycles for one week prior and three weeks following BLM administration. Meanwhile, the ad libitum feeding group had unrestricted access to food throughout the experiment. The evaluation focused on lung pathology via histological staining, qPCR analysis of collagen markers, and immune cell profiling through flow cytometry.

RESULTS

IF group significantly reduced inflammation and fibrosis in lung tissues of BLM-induced mice compared to ad libitum feeding group. qPCR results showed IF remarkably decreased the mRNA expression of Col 1a and Col 3a in the lungs of BLM-induced mouse models. IF also reduced the numbers of regulatory T cells (Tregs), T helper 17 (Th17) cells, monocytes, and monocyte-derived alveolar macrophages (MoAMs) in the lung tissues.

CONCLUSIONS

IF may improve BLM-induced pulmonary fibrosis by decreasing numbers of immune cells including Treg cells, Th17 ​cells, monocytes, and MoAMs in the lungs. This study offers experimental validation for dietary intervention as a viable treatment modality in IPF management.

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.

Unravelling monocyte functions: from the guardians of health to the regulators of disease

Monocytes are a key component of the innate immune system. They undergo intricate developmental processes within the bone marrow, leading to diverse monocyte subsets in the circulation. In a state of healthy homeostasis, monocytes are continuously released into the bloodstream, destined to repopulate specific tissue-resident macrophage pools where they fulfil tissue-specific functions. However, under pathological conditions monocytes adopt various phenotypes to resolve inflammation and return to a healthy physiological state. This review explores the nuanced developmental pathways and functional roles that monocytes perform, shedding light on their significance in both physiological and pathological contexts.

Mononuclear Phagocytes, Cellular Immunity, and Nobel Prizes: A Historic Perspective

The mononuclear phagocyte system includes monocytes, macrophages, some dendritic cells, and multinuclear giant cells. These cell populations display marked heterogeneity depending on their differentiation from embryonic and bone marrow hematopoietic progenitors, tissue location, and activation. They contribute to tissue homeostasis by interacting with local and systemic immune and non-immune cells through trophic, clearance, and cytocidal functions. During evolution, they contributed to the innate host defense before effector mechanisms of specific adaptive immunity emerged. Mouse macrophages appear at mid-gestation and are distributed throughout the embryo to facilitate organogenesis and clear cells undergoing programmed cell death. Yolk sac, AGM, and fetal liver-derived tissue-resident macrophages persist throughout postnatal and adult life, supplemented by bone marrow-derived blood monocytes, as required after injury and infection. Nobel awards to Elie Metchnikoff and Paul Ehrlich in 1908 drew attention to cellular phagocytic and humoral immunity, respectively. In 2011, prizes were awarded to Jules Hoffmann and Bruce Beutler for contributions to innate immunity and to Ralph Steinman for the discovery of dendritic cells and their role in antigen presentation to T lymphocytes. We trace milestones in the history of mononuclear phagocyte research from the perspective of Nobel awards bearing directly and indirectly on their role in cellular immunity.

Fasting reshapes tissue-specific niches to improve NK cell-mediated anti-tumor immunity

Fasting is associated with improved outcomes in cancer. Here, we investigated the impact of fasting on natural killer (NK) cell anti-tumor immunity. Cyclic fasting improved immunity against solid and metastatic tumors in an NK cell-dependent manner. During fasting, NK cells underwent redistribution from peripheral tissues to the bone marrow (BM). In humans, fasting also reduced circulating NK cell numbers. NK cells in the spleen of fasted mice were metabolically rewired by elevated concentrations of fatty acids and glucocorticoids, augmenting fatty acid metabolism via increased expression of the enzyme CPT1A, and Cpt1a deletion impaired NK cell survival and function in this setting. In parallel, redistribution of NK cells to the BM during fasting required the trafficking mediators S1PR5 and CXCR4. These cells were primed by an increased pool of interleukin (IL)-12-expressing BM myeloid cells, which improved IFN-γ production. Our findings identify a link between dietary restriction and optimized innate immune responses, with the potential to enhance immunotherapy strategies.

Beneficial effects of intermittent fasting on nonalcoholic fatty liver disease: a narrative review

Nonalcoholic fatty liver disease (NAFLD) is one of the most common chronic liver diseases, and it is characterized by a series of fatty liver diseases that can lead to severe liver disease. Although no therapeutic drug has been approved as an effective therapy for NAFLD to date, dietary changes and physical activity are thought to be the cornerstone of NAFLD management. For this reason, some articles are available to analyze the studies done so far using various modifications of intermittent fasting (IF) among animals and patients with NAFLD. Data from preclinical and clinical trials suggested that IF positively impacts inflammatory and metabolic markers in both animals and humans. Inflammation and oxidative stress are the major risk factors involved in the pathogenesis of NAFLD. IF has been shown to have positive benefits in alleviating metabolic disorders, promoting the browning of white tissue, resetting circadian rhythm, and activating autophagy of cells. This review is intended to provide a detailed synopsis of the protocols, potential mechanisms of action, and supporting evidence for IF in NAFLD. We will highlight what is currently known about IF approaches in NAFLD treatments in clinical populations with mechanism insight from animal studies, and the safety concerns in certain patient groups.

Graphical Abstract

The protocols of intermittent fasting (IF) are various. Data from trials suggested that IF positively impacts both humans and animals. IF has been shown to have potential treatments for nonalcoholic fatty liver disease.

Fasting and calorie restriction modulate age-associated immunosenescence and inflammaging

Aging is a multifaceted process impacting cells, tissues, organs, and organ systems of the body. Like other systems, aging affects both the adaptive and the innate components of the immune system, a phenomenon known as immunosenescence. The deregulation of the immune system puts elderly individuals at higher risk of infection, lower response to vaccines, and increased incidence of cancer. In the Western world, overnutrition has increased the incidence of obesity (linked with chronic inflammation) which increases the risk of metabolic syndrome, cardiovascular disease, and cancer. Aging is also associated with inflammaging a sterile chronic inflammation that predisposes individuals to age-associated disease. Genetic manipulation of the nutrient-sensing pathway, fasting, and calorie restriction (CR) has been shown to increase the lifespan of model organisms. As well in humans, fasting and CR have also been shown to improve different health parameters. Yet the direct effect of fasting and CR on the aging immune system needs to be further explored. Identifying the effect of fasting and CR on the immune system and how it modulates different parameters of immunosenescence could be important in designing pharmacological or nutritional interventions that slow or revert immunosenescence and strengthen the immune system of elderly individuals. Furthermore, clinical intervention can also be planned, by incorporating fasting or CR with medication, chemotherapy, and vaccination regimes. This review discusses age-associated changes in the immune system and how these changes are modified by fasting and CR which add information on interventions that promote healthy aging and longevity in the growing aging population.

Atypical monocyte dynamics in healthy humans in response to fasting and refeeding are distinguished by fasting HDL and postprandial cortisol

Monocytes are innate immune cells that are continuously produced in bone marrow which enter and circulate the vasculature. In response to nutrient scarcity, monocytes migrate back to bone marrow, where, upon refeeding, they are rereleased back into the bloodstream to replenish the circulation. In humans, the variability in monocyte behavior in response to fasting and refeeding has not been characterized. To investigate monocyte dynamics in humans, we measured blood monocyte fluctuations in 354 clinically healthy individuals after a 12-h overnight fast and at 3 and 6 h after consuming a mixed macronutrient challenge meal. Using cluster analysis, we identified three distinct monocyte behaviors. Group 1 was characterized by relatively low fasting monocyte counts that markedly increased after consuming the test meal. Group 2 was characterized by relatively high fasting monocyte counts that decreased after meal consumption. Group 3, like Group 1, was characterized by lower fasting monocyte counts but increased to a lesser extent after consuming the meal. Although monocyte fluctuations observed in Groups 1 and 3 align with the current paradigm of monocyte dynamics in response to fasting and refeeding, the atypical dynamic observed in Group 2 does not. Although generally younger in age, Group 2 subjects had lower whole body carbohydrate oxidation rates, lower HDL-cholesterol levels, delayed postprandial declines in salivary cortisol, and reduced postprandial peripheral microvascular endothelial function. These unique characteristics were not explained by group differences in age, sex, or body mass index (BMI). Taken together, these results highlight distinct patterns of monocyte responsiveness to natural fluctuations in dietary fuel availability.NEW & NOTEWORTHY Our study composed of adult volunteers revealed that monocyte dynamics exhibit a high degree of individual variation in response to fasting and refeeding. Although circulating monocytes in most volunteers behaved in ways that align with previous reports, many exhibited atypical dynamics demonstrated by elevated fasting blood monocyte counts that sharply decreased after meal consumption. This group was also distinguished by lower HDL levels, reduced postprandial endothelial function, and a delayed postprandial decline in salivary cortisol.

Dietary and water restriction leads to increased susceptibility to antimicrobial resistant pathogens

Dehydration and malnutrition are common and often underdiagnosed in hospital settings. Multidrug-resistant bacterial infections result in more than 35,000 deaths a year in nosocomial patients. The effect of temporal dietary and water restriction (DWR) on susceptibility to multidrug-resistant pathogens is unknown. We report that DWR markedly increased susceptibility to systemic infection by ESKAPE pathogens. Using a murine bloodstream model of methicillin-resistant Staphylococcus aureus infection, we show that DWR leads to significantly increased mortality and morbidity. DWR causes increased bacterial burden, severe pathology, and increased numbers of phagocytes in the kidney. DWR appears to alter the functionality of these phagocytes and is therefore unable to control infection. Mechanistically, we show that DWR impairs the ability of macrophages to phagocytose multiple bacterial pathogens and efferocytose apoptotic neutrophils. Together, this work highlights the crucial impact that diet and hydration play in protecting against infection.

The BJA Editorial Fellowship 2024: a barometer for the state of academic anaesthesiology, perioperative, pain, and critical care medicine

Throughout its 100-yr history, a key ambition of the British Journal of Anaesthesia has been to foster our academic community by addressing the needs of individuals in the early stages of their independent clinical and research careers. Longitudinal mentoring and peer networking are critical for establishing a community of like-minded peers and mentor-advisors required to navigate the challenges of academic medicine. In 2019, the Journal launched an Editorial Fellowship scheme, aimed at comprehensively demystifying the process of peer review, editing, and publishing through guided mentorship and experiential learning.

A National Study Exploring the Association between Fasting Duration and Mortality among the Elderly

(1) Background: The benefits of weight management are widely recognized, and prolonged fasting duration has become a common method for weight control. The suitability of time-restricted eating (TRE) for elderly individuals remains controversial. This study aims to examine the correlation between fasting duration and mortality within a nationally representative cohort of elderly individuals in the United States. (2) Methods: Data were extracted from a prospective cohort study conducted as part of the National Health and Nutrition Examination Survey (NHANES) from 2005 to 2018. Participants aged over 60 with complete data on dietary intake and mortality follow-up information were included. Fasting duration was assessed using two 24 h dietary recalls. All the participants were categorized into fasting duration quartiles. Mortality outcomes were ascertained through the National Death Index. Cox proportional hazards regression models were utilized to analyze the association between fasting duration and mortality. (3) Results: The final analysis included 10,561 elderly participants (mean age 69.89, 45.58% male). Individuals with the longest fasting duration (over 12.38 h) had a significantly higher risk of CVD mortality compared to those with a normal fasting duration (10.58-12.38 h). This elevated CVD mortality risk was particularly pronounced in males, individuals over 70 years old, and non-shift workers. A non-linear relationship was observed between fasting duration and all-cause mortality and CVD mortality. (4) Conclusions: Prolonged fasting periods are associated with a higher risk of CVD mortality in the elderly population, although this correlation is not evident for all-cause, cancer, or other-cause mortality. A fasting duration of 11.49 h correlates with the lowest mortality risk. Additionally, elderly individuals with the shortest fasting duration exhibit elevated hazard ratios for both cancer and other-cause mortality. As with any health intervention, clinicians should exercise caution when recommending a fasting regimen that is personalized to the health condition of people who are older. Further research through randomized controlled trials should be conducted to comprehensively investigate the impact of TRE on mortality.

Classical monocyte ontogeny dictates their functions and fates as tissue macrophages

Classical monocytes (CMs) are ephemeral myeloid immune cells that circulate in the blood. Emerging evidence suggests that CMs can have distinct ontogeny and originate from either granulocyte-monocyte- or monocyte-dendritic-cell progenitors (GMPs or MDPs). Here, we report surface markers that allowed segregation of murine GMP- and MDP-derived CMs, i.e., GMP-Mo and MDP-Mo, as well as their functional characterization, including fate definition following adoptive cell transfer. GMP-Mo and MDP-Mo yielded an equal increase in homeostatic CM progeny, such as blood-resident non-classical monocytes and gut macrophages; however, these cells differentially seeded various other selected tissues, including the dura mater and lung. Specifically, GMP-Mo and MDP-Mo differentiated into distinct interstitial lung macrophages, linking CM dichotomy to previously reported pulmonary macrophage heterogeneity. Collectively, we provide evidence for the existence of two functionally distinct CM subsets in the mouse that differentially contribute to peripheral tissue macrophage populations in homeostasis and following challenge.

Intermittent fasting alleviates IMQ-induced psoriasis-like dermatitis via reduced γδT17 and monocytes in mice

Psoriasis is a chronic immune mediated inflammatory skin disease with systemic manifestations. It has been reported that caloric restriction could improve severity of psoriasis patients. However, the mechanism of intermittent fasting effects on psoriasis has not been investigated. Caloric restriction is known to reduce the number of circulating inflammatory monocytes in a CCL2-dependent manner. However, it is still unknown whether caloric restriction can improve psoriasis by regulating monocytes through CCL2. In this study, we used imiquimod (IMQ)-induced psoriasis-like mouse model to explore the effects and the mechanisms of intermittent fasting on psoriasis-like dermatitis. We found that intermittent fasting could significantly improve IMQ-induced psoriasis-like dermatitis, and reduce the number of γδT17 cells and IL-17 production in draining lymph nodes and psoriatic lesion via inhibiting proliferation and increasing death of γδT17 cells. Furthermore, intermittent fasting could significantly decrease monocytes in blood, and this was associated with decreased monocytes, macrophages and DC in psoriasis-like skin inflammation. Reduced monocytes in circulation and increased monocytes in BM of fasting IMQ-induced psoriasis-like mice is through reducing the production of CCL2 from BM to inhibit monocyte egress to the periphery. Our above data shads light on the mechanisms of intermittent fasting on psoriasis.

Physiologic disruption and metabolic reprogramming in infection and sepsis

Effective responses against severe systemic infection require coordination between two complementary defense strategies that minimize the negative impact of infection on the host: resistance, aimed at pathogen elimination, and disease tolerance, which limits tissue damage and preserves organ function. Resistance and disease tolerance mostly rely on divergent metabolic programs that may not operate simultaneously in time and space. Due to evolutionary reasons, the host initially prioritizes the elimination of the pathogen, leading to dominant resistance mechanisms at the potential expense of disease tolerance, which can contribute to organ failure. Here, we summarize our current understanding of the role of physiological perturbations resulting from infection in immune response dynamics and the metabolic program requirements associated with resistance and disease tolerance mechanisms. We then discuss how insight into the interplay of these mechanisms could inform future research aimed at improving sepsis outcomes and the potential for therapeutic interventions.

Metabolic programming of organ-specific natural killer cell responses

Cells of the mammalian innate immune system have evolved to protect the host from various environmental or internal insults and injuries which perturb the homeostatic state of the organism. Among the lymphocytes of the innate immune system are natural killer (NK) cells, which circulate and survey host tissues for signs of stress, including infection or transformation. NK cells rapidly eliminate damaged cells in the blood or within tissues through secretion of cytolytic machinery and production of proinflammatory cytokines. To perform these effector functions while traversing between the blood and tissues, patrolling NK cells require sufficient fuel to meet their energetic demands. Here, we highlight the ability of NK cells to metabolically adapt across tissues, during times of nutrient deprivation and within tumor microenvironments. Whether at steady state, or during viral infection and cancer, NK cells readily shift their nutrient uptake and usage in order to maintain metabolism, survival, and function.

Hematopoietic Stem Cells as an Integrative Hub Linking Lifestyle to Cardiovascular Health

Despite breakthroughs in modern medical care, the incidence of cardiovascular disease (CVD) is even more prevalent globally. Increasing epidemiologic evidence indicates that emerging cardiovascular risk factors arising from the modern lifestyle, including psychosocial stress, sleep problems, unhealthy diet patterns, physical inactivity/sedentary behavior, alcohol consumption, and tobacco smoking, contribute significantly to this worldwide epidemic, while its underpinning mechanisms are enigmatic. Hematological and immune systems were recently demonstrated to play integrative roles in linking lifestyle to cardiovascular health. In particular, alterations in hematopoietic stem cell (HSC) homeostasis, which is usually characterized by proliferation, expansion, mobilization, megakaryocyte/myeloid-biased differentiation, and/or the pro-inflammatory priming of HSCs, have been shown to be involved in the persistent overproduction of pro-inflammatory myeloid leukocytes and platelets, the cellular protagonists of cardiovascular inflammation and thrombosis, respectively. Furthermore, certain lifestyle factors, such as a healthy diet pattern and physical exercise, have been documented to exert cardiovascular protective effects through promoting quiescence, bone marrow retention, balanced differentiation, and/or the anti-inflammatory priming of HSCs. Here, we review the current understanding of and progression in research on the mechanistic interrelationships among lifestyle, HSC homeostasis, and cardiovascular health. Given that adhering to a healthy lifestyle has become a mainstream primary preventative approach to lowering the cardiovascular burden, unmasking the causal links between lifestyle and cardiovascular health from the perspective of hematopoiesis would open new opportunities to prevent and treat CVD in the present age.

Characterization of three lamp genes from largemouth bass (Micropterus salmoides): molecular cloning, expression patterns, and their transcriptional levels in response to fast and refeeding strategy

Lysosomes-associated membrane proteins (LAMPs), a family of glycosylated proteins and major constituents of the lysosomal membranes, play a dominant role in various cellular processes, including phagocytosis, autophagy and immunity in mammals. However, their roles in aquatic species remain poorly known. In the present study, three lamp genes were cloned and characterized from Micropterus salmoides. Subsequently, their transcriptional levels in response to different nutritional status were investigated. The full-length coding sequences of lamp1, lamp2 and lamp3 were 1251bp, 1224bp and 771bp, encoding 416, 407 and 256 amino acids, respectively. Multiple sequence alignment showed that LAMP1-3 were highly conserved among the different fish species, respectively. 3-D structure prediction, genomic survey, and phylogenetic analysis were further confirmed that these genes are widely existed in vertebrates. The mRNA expression of the three genes was ubiquitously expressed in all selected tissues, including liver, brain, gill, heart, muscle, spleen, kidney, stomach, adipose and intestine, lamp1 shows highly transcript levels in brain and muscle, lamp2 displays highly expression level in heart, muscle and spleen, but lamp3 shows highly transcript level in spleen, liver and kidney. To analyze the function of the three genes under starvation stress in largemouth bass, three experimental treatment groups (fasted group and refeeding group, control group) were established in the current study. The results indicated that the expression of lamp1 was significant induced after starvation, and then returned to normal levels after refeeding in the liver. The expression of lamp2 and lamp3 exhibited the same trend in the liver. In addition, in the spleen and the kidney, the transcript level of lamp1 and lamp2 was remarkably increased in the fasted treatment group and slightly decreased in the refed treatment group, respectively. Collectively, our findings suggest that three lamp genes may have differential function in the immune and energetic organism in largemouth bass, which is helpful in understanding roles of lamps in aquatic species.

Time-restricted feeding prevents ionizing radiation-induced hematopoietic stem cell damage by inhibiting NOX-4/ROS/p38 MAPK pathway

Ionizing radiation (IR)-induced damage to the hematopoietic system is a prominent symptom following exposure to total body irradiation (TBI). The exploration of strategies aimed at to mitigating radiation-induced hematopoietic damage assumes paramount importance. Time-restricted feeding (TRF) has garnered attention for its beneficial effects in various diseases. In this study, we evaluated the preventive effects of TRF on TBI-induced hematopoietic damage. The results suggested that TRF significantly enhanced the proportion and function of hematopoietic stem cells in mice exposed to 4 Gy TBI. These effects might be attributed to the inhibition of the NOX-4/ROS/p38 MAPK pathway in hematopoietic stem cells. TRF also influenced the expression of nuclear factor erythroid2-related factor 2 and increased glutathione peroxidase activity, thereby promoting the clearance of reactive oxygen species. Furthermore, TRF alleviated aberrations in plasma metabolism by inhibiting the mammalian target of rapamycin. These findings suggest that TRF may represent a novel approach to preventing hematopoietic radiation damage.

Propionate functions as a feeding state-dependent regulatory metabolite to counter proinflammatory signaling linked to nutrient load and obesity

Generally, fasting and refeeding confer anti- and proinflammatory effects, respectively. In humans, these caloric-load interventions function, in part, via regulation of CD4+ T cell biology. However, mechanisms orchestrating this regulation remain incomplete. We employed integrative bioinformatics of RNA sequencing and high-performance liquid chromatography-mass spectrometry data to measure serum metabolites and gene expression of peripheral blood mononuclear cells isolated from fasting and refeeding in volunteers to identify nutrient-load metabolite-driven immunoregulation. Propionate, a short chain fatty acid (SCFA), and the SCFA-sensing G protein-coupled receptor 43 (ffar2) were coordinately and inversely regulated by fasting and refeeding. Propionate and free fatty acid receptor agonists decreased interferon-γ and interleukin-17 and significantly blunted histone deacetylase activity in CD4+ T cells. Furthermore, propionate blunted nuclear factor κB activity and diminished interleukin-6 release. In parallel, propionate reduced phosphorylation of canonical T helper 1 (TH1) and TH17 regulators, STAT1 and STAT3, respectively. Conversely, knockdown of free fatty acid receptors significantly attenuated the anti-inflammatory role of propionate. Interestingly, propionate recapitulated the blunting of CD4+ TH cell activation in primary cells from obese individuals, extending the role of this metabolite to a disease associated with low-grade inflammation. Together, these data identify a nutrient-load responsive SCFA-G protein-coupled receptor linked pathway to regulate CD4+ TH cell immune responsiveness.

Fasting-activated ventrolateral medulla neurons regulate T cell homing and suppress autoimmune disease in mice

Dietary fasting markedly influences the distribution and function of immune cells and exerts potent immunosuppressive effects. However, the mechanisms through which fasting regulates immunity remain obscure. Here we report that catecholaminergic (CA) neurons in the ventrolateral medulla (VLM) are activated during fasting in mice, and we demonstrate that the activity of these CA neurons impacts the distribution of T cells and the development of autoimmune disease in an experimental autoimmune encephalomyelitis (EAE) model. Ablation of VLM CA neurons largely reversed fasting-mediated T cell redistribution. Activation of these neurons drove T cell homing to bone marrow in a CXCR4/CXCL12 axis-dependent manner, which may be mediated by a neural circuit that stimulates corticosterone secretion. Similar to fasting, the continuous activation of VLM CA neurons suppressed T cell activation, proliferation, differentiation and cytokine production in autoimmune mouse models and substantially alleviated disease symptoms. Collectively, our study demonstrates neuronal control of inflammation and T cell distribution, suggesting a neural mechanism underlying fasting-mediated immune regulation.

Effects of lifestyle factors on leukocytes in cardiovascular health and disease

Exercise, stress, sleep and diet are four distinct but intertwined lifestyle factors that influence the cardiovascular system. Abundant epidemiological, clinical and preclinical studies have underscored the importance of managing stress, having good sleep hygiene and responsible eating habits and exercising regularly. We are born with a genetic blueprint that can protect us against or predispose us to a particular disease. However, lifestyle factors build upon and profoundly influence those predispositions. Studies in the past 10 years have shown that the immune system in general and leukocytes in particular are particularly susceptible to environmental perturbations. Lifestyle factors such as stress, sleep, diet and exercise affect leukocyte behaviour and function and thus the immune system at large. In this Review, we explore the various mechanisms by which lifestyle factors modulate haematopoiesis and leukocyte migration and function in the context of cardiovascular health. We pay particular attention to the role of the nervous system as the key executor that connects environmental influences to leukocyte behaviour.