Circadian physiology of metabolism

Decoding the Liver-Heart Axis in Cardiometabolic Diseases

The liver and heart are closely interconnected organs, and their bidirectional interaction plays a central role in cardiometabolic disease. In this review, we summarize current evidence linking liver dysfunction-particularly metabolic dysfunction-associated steatotic liver disease, alcohol-associated liver disease, and cirrhosis-with an increased risk of heart failure and other cardiovascular diseases. We discuss how these liver conditions contribute to cardiac remodeling, systemic inflammation, and hemodynamic stress and how cardiac dysfunction in turn impairs liver perfusion and promotes hepatic injury. Particular attention is given to the molecular mediators of liver-heart communication, including hepatokines and cardiokines, as well as the emerging role of advanced research methodologies, including omics integration, proximity labeling, and organ-on-chip platforms, that are redefining our understanding of interorgan cross talk. By integrating mechanistic insights with translational tools, this review aims to support the development of multiorgan therapeutic strategies for cardiometabolic disease.

The Pro-Apoptotic Effect of Glucose Restriction in NSCLC via AMPK-Regulated Circadian Clock Gene Bmal1

The circadian clock is a crucial regulator of mammalian physiology, controlling daily oscillations in key biological processes, such as cell proliferation, apoptosis, and DNA damage repair. Disruption of circadian rhythms has been identified as a significant risk factor for cancer development and progression, yet the specific molecular mechanisms linking circadian dysfunction to cancer remain poorly understood. Recent studies have increasingly focused on the role of diet in modulating circadian rhythms, highlighting the potential for dietary interventions in cancer management. However, how dietary factors like glucose restriction interact with circadian rhythms to influence cancer cell behavior remains an open question. Here, we investigate the mechanisms underlying glucose restriction-induced apoptosis in non-small cell lung cancer (NSCLC) cells, with a focus on the role of circadian clock genes. Analysis of the GEPIA database revealed that the circadian gene Bmal1 is highly expressed in normal tissues and associated with better prognosis in lung adenocarcinoma patients. In NSCLC cells, Bmal1 expression correlated with proapoptotic gene activity. In a tumor xenograft model using severe combined immunodeficiency (SCID) mice, a glucose-restricted (ketogenic) diet significantly delayed tumor growth and increased the expression of Bmal1 and proapoptotic genes. These findings suggest that glucose restriction promotes apoptosis in NSCLC cells through a Bmal1-mediated pathway, providing novel insights into the intersection between circadian regulation and cancer biology. Targeting core circadian clock genes like Bmal1 may represent a promising therapeutic strategy for managing lung cancer, broadening our understanding of how circadian rhythms can be harnessed for cancer prevention and treatment.

Circadian clock-independent ultradian rhythms in lipid metabolism in the Drosophila fat body

The role of circadian clocks in regulating metabolic processes is well known; however, their impact on metabolic states across species and life stages remains largely unexplored. This study investigates the relationship between circadian rhythms and metabolic regulation in the Drosophila larval fat body, a metabolic hub analogous to the mammalian liver and adipose tissue. Surprisingly, the fat body of period null mutants, which lack a functional circadian clock in all tissues, exhibited 12-hour rhythms in gene expression, particularly those involved in peroxisome function, lipid metabolism, and oxidative stress response. These transcriptomic rhythms were aligned with 12-hour oscillations in peroxisome biogenesis and activity, reactive oxygen species levels, and lipid peroxidation. Furthermore, period mutants exhibited 12-hour rhythms in body fat storage, ultimately leading to a net reduction in body fat levels. Collectively, our results identify clock-independent ultradian rhythms in lipid metabolism that are essential for larval survival and development.

Single-Cell Multiomic Analysis of Circadian Rhythmicity in Mouse Liver

From bacteria to humans, most organisms showcase inherent 24-hour circadian rhythms, best exemplified by the sleep-wake cycle. These rhythms are remarkably widespread, governing hormonal, metabolic, physiological, and behavioral oscillations, and are driven by "molecular clocks" that orchestrate the rhythmic expression of thousands of genes throughout the body. Here, we generate single-cell RNA and ATAC multiomic data to simultaneously characterize gene expression and chromatin accessibility of ~33,000 mouse liver cells across the 24-hour day. Our study yields several key insights, including: (i) detecting circadian rhythmicity in both discretized liver cell types and transient sub-lobule cell states, capturing space-time RNA and ATAC profiles in a cell-type- and cell-state-specific manner; (ii) delving beyond mean cyclic patterns to characterize distributions, accounting for gene expression stochasticity due to transcriptional bursting; (iii) interrogating multimodal circadian rhythmicity, encompassing RNAs, DNA regulatory elements, and transcription factors (TFs), while examining priming and lagging effects across modalities; and (iv) inferring spatiotemporal gene regulatory networks involving target genes, TFs, and cis-regulatory elements that controls circadian rhythmicity and liver physiology. Our findings apply to existing single-cell data of mouse and Drosophila brains and are further validated by time-series single molecule fluorescence in situ hybridization, as well as vast amounts of existing and orthogonal high-throughput data from chromatin immunoprecipitation followed by sequencing, capture Hi-C, and TF knockout experiments. Altogether, our study constructs a comprehensive map of the time-series transcriptomic and epigenomic landscapes that elucidate the function and mechanism of the liver peripheral clocks.

Integration of photoperiod and time-restricted feeding on the circadian gene rhythms in juvenile salmon

The circadian clock has evolved to synchronize animal behaviour and physiology with the external environment. Present in almost all cells, the clock is made up of a transcription-translation feedback loop that is responsive to cues such as light/dark cycles (photoperiod) and the time of feeding. Chinook salmon (Oncorhynchus tshawytscha) is a fish species whose clock is thought to be adapted in natural populations according to their latitude, where photoperiod variation can be extreme in northern spring/summer conditions. Here, we probed for the expression of circadian clock genes in four tissues of juvenile Chinook salmon under different environmental conditions. We find that the circadian clock is optimal when photoperiod is coupled with regular feeding during daylight hours. We further tested the effects of constant light and time-restricted feeding, environmental factors that are known to affect daily gene expression rhythms, on the expression of clock genes, appetite-regulating hormones, and metabolic regulators in the intestine of juvenile Chinook. We find that overall constant light is chrono-disruptive irrespective of the timing of food. The resulting disruption in gene expression produces aberrant rhythms, and affects glucose homeostasis, despite an increase in growth. Our data suggests photoperiod and time-restricted feeding could be optimized in Chinook aquaculture and raise the question of whether and how photoperiod changes are compensated in northern-adapted populations.

Combined influence of fluctuations in the environmental conditions and space weather on the chrono-periodic system in cardiovascular pathology

This review aims to explore the impact of natural environmental factors on human health and cardiovascular pathology. The precise ways in which complex life forms adapted to these factors remain unclear. However, it is known that Homo sapiens evolved cardiovascular and neurological systems, which generate electromagnetic fields as part of their function. It is still uncertain how the human body may have utilized external electromagnetic fields to regulate its processes. Additionally, we will discuss the mechanisms related to environmental factors that may have influenced evolutionary pathways. This review paper also examines the impact of oscillations in natural environmental factors on human chrono-periodic systems. The human body is influenced by various fluctuations in both external and internal factors, some of which can potentially disrupt homeostasis. Animals and humans have the ability to anticipate external signal. The chrono-periodic system of the human body is responsible for this "premonition". It would be incorrect to assume that specific reactions to each stimulus were fully developed and fixed during evolution. Except for genetic defects, it is unlikely that the human body evolved to have fixed pathological reactions, as this would contradict the principles of natural selection. Therefore, all typical responses of the human body to stimuli should be considered physiological, meaning they are adaptive.

48-Hour and 24-Hour Time-lapse Single-nucleus Transcriptomics Reveal Cell-type specific Circadian Rhythms in Arabidopsis

Functional circadian clock is critical to the adaptation and survival of organisms. In land plants, the comprehensive profiling of circadian gene expression at the single-cell level is largely unknown partly due to the challenges in obtaining precisely-timed single cells embedded within cell walls. To bridge this gap, we employ time-lapse single-nucleus RNA sequencing (snRNA-seq) on Arabidopsis seedlings collected over a 48-hour window at 4-hour intervals, as well as over a 24-hour day at 2-hour intervals, yielding a total of over 77,142 and 130,000 nuclei. Here, we find that four cell clusters in the shoot share a coherent rhythm, while around 3000 genes display cell-type specific rhythmic expression. Our analysis indicates that genes encoding circadian regulators oscillate in multiple cell types, and the majority of them are well-documented core clock genes, suggesting the snRNA-seq circadian data could be used to identify more clock components oscillating in a cell-autonomous way. We identify ABF1 as a circadian regulator, whose overexpression and shortens the circadian period. Our data provides a comprehensive resource for plant circadian rhythmicity at the single-cell level (hosted at https://zhailab.bio.sustech.edu.cn/sc_circadian ).

Daily rhythms of glucose, insulin, and nonesterified fatty acid responses to an intravenous glucose tolerance test in dairy cows

In nonruminant species, glucose tolerance and insulin sensitivity are known to be regulated by circadian rhythms, which are repeating ∼24-h cycles that govern many aspects of behavior, physiology, and metabolism. However, it is unknown if these rhythms exist in dairy cows. Our objective was to determine the fit of a daily rhythm of glucose, insulin, and nonesterified fatty acid (NEFA) clearance rates independent of daily patterns of nutrient intake. To accomplish our objective, 12 multiparous lactating Holstein cows were enrolled in a within-subject design conducted over 2 experimental periods (n = 6/period). Within each period, cows were subjected to intravenous glucose tolerance tests (IVGTT) at 4 timepoints, representing different times of the day (0300, 0900, 1500, and 2100 h). The 0900 and 2100 h IVGTT were performed 36 h apart, followed by a 7-d washout, and then the 1500 and 0300 h IVGTT were performed 36 h apart. Cows were fed 12 times/d at 2-h intervals beginning 24 h before the first IVGTT in each set until the second IVGTT in each set to stabilize feed intake across the day, with 1 time/d feeding occurring during the washout period. For each IVGTT, 250 g of glucose was infused as a 50% (wt/vol) d-glucose solution via a jugular catheter and blood was collected at -15, -5, immediately before, 0, 5, 10, 15, 20, 30, 45, 60, 90, and 120 min relative to infusion. A linear mixed model with the fixed effects of cosine and sine and random effect of cow within period was used for the outcomes of clearance rate, half-life, baseline concentration, time to baseline concentration, and area under the curve (AUC) for glucose, insulin, and NEFA. A zero-amplitude test was used to determine the fit of a 24-h cosine function and cosinor rhythmometry was used to determine the amplitude and acrophase of the 24-h rhythm. Insulin concentrations at baseline followed a diurnal rhythm. Glucose and insulin clearance rate, half-life, and AUC also followed a diurnal rhythm. Glucose and insulin clearance rates peaked at 1247 h and 0944 h, respectively. No circadian rhythm was detected for plasma NEFA concentrations. Results suggest that insulin-stimulated glucose uptake is controlled differently throughout the day by circadian rhythms.

Lactate induces oxidative stress by HIF1α stabilization and circadian clock disturbance in mammary gland of dairy cows

BACKGROUND

Lactate is a classical byproduct of glucose metabolism, and the main lactate production pathway depends on glycolysis. Lactate stabilized HIF1α by inhibiting PHD activity, leading to hypoxic stress response and exacerbating glycolysis in multiple tissues. However, the redox induction mechanism of lactate in mammary gland has not been understood yet. Herein, we describe a lactate-responsive HIF1α/circadian control mechanism in oxidative stress in the mammary glands of dairy cows.

RESULTS

The in vivo study showed that dairy cows with high lactate concentrations are associated with reduced milk yield and more ROS accumulation in mammary gland. Western blot results in MAC-T cells showed positive correlation between lactate concentrations, expression of HIF1α and oxidative stress indicators, but not circadian core components. To test how lactate-mediated HIF1α dysfunction leads to cell protection process, we investigated altered expression of circadian core related genes following HIF1α stabilization. We found that stabilized HIF1α by lactate inhibited stimulated expression of circadian core components due to the similarity of HRE and E-box transcription elements. Furthermore, we found that lactate treatment strengthened the binding of HIF1α with BMAL1, HMOX1 and FOXO3 in MAC-T cells. Moreover, HIF1α knockdown altered expression of circadian rhythm related genes and reduced oxidative stress state.

CONCLUSION

In summary, our study highlights the central role of competitive transcriptional element occupancy in lactate-mediated oxidative stress of mammary gland, which is caused by HIF1α stabilization and circadian rhythm dysfunction. Our findings introduce a novel nutritional strategy with potential applications in dairy farming for optimizing milk production and maintaining mammary gland health.

Diurnal timing of physical activity in relation to obesity and diabetes in the German National Cohort (NAKO)

BACKGROUND

Physical activity supports weight regulation and metabolic health, but its timing in relation to obesity and diabetes remains unclear. We aimed to assess the diurnal timing of physical activity and its association with obesity and diabetes.

METHODS

We cross-sectionally analyzed hip-worn accelerometry data from 61,116 participants aged 20-75 in the German National Cohort between 2015 and 2019. We divided physical activity into sex- and age-standardized quartiles of total morning (06:00-11:59), afternoon (12:00-17:59), evening (18:00-23:59), and nighttime (00:00-06:00) physical activity. Using multivariable logistic regression, we estimated associations of physical activity timing with obesity (BMI ≥ 30.0 kg/m2) and diabetes (self-reported or HbA1c ≥ 6.5%). We accounted for sex, age, study region, education, employment, risky alcohol use, smoking, night shift work, and sleep duration.

RESULTS

High afternoon (top vs. bottom quartile, OR: 0.36, 95% CI: 0.33-0.38) and evening physical activity (OR: 0.45, 95% CI: 0.42-0.48) showed lower obesity odds than high morning activity (OR: 0.71, 95% CI: 0.66-0.76), whereas nighttime activity increased obesity odds (OR: 1.58, 95% CI: 1.48-1.68). Associations were similar for diabetes, with the lowest odds for afternoon (OR: 0.47, 95% CI: 0.42-0.53), followed by evening (OR: 0.56, 95% CI: 0.50-0.62) and morning activity (OR: 0.80, 95% CI: 0.71-0.89), and higher odds for nighttime activity (OR: 1.43, 95% CI: 1.29-1.58). Findings were not modified by employment status, night shift work, and sleep duration.

CONCLUSIONS

Our cross-sectional findings require longitudinal corroboration but suggest afternoon and evening activity provide greater metabolic health benefits than morning activity, while nighttime activity is discouraged.

What are the effects of time-restricted eating upon metabolic health outcomes in individuals with metabolic syndrome: A scoping review

The primary objective of this scoping review (ScR) was to assess the breadth and type of evidence related to time-restricted eating (TRE) as an intervention to modify metabolic health outcomes in individuals with diagnosed metabolic syndrome (MetS), a major health challenge due to increasing prevalence and association with other chronic diseases. MetS comprises three or more of hypertension, hypercholesterolaemia, dyslipidaemia, dysregulated glucose homeostasis, and abdominal obesity. TRE, also known as time-restricted feeding (TRF), restricts food intake to specific time windows within a day, for example, a 10-h eating period between 10:00 and 20:00. Via multiple mechanisms, TRE interventions may provide an effective tool to prevent and treat metabolic disease such as MetS. While studies have assessed TRE in populations with components of MetS, there is a gap in the knowledge of how effective TRE can be for people with diagnosed MetS. A search of studies published in English in the PubMed (Medline), Embase, Cochrane, and PROSPERO databases was performed in February 2024. Of 3449 articles, 45 underwent full text analysis, and three were accepted into the ScR. These studies, comprising 10 and 8 h TRE interventions for 12 weeks, showed mixed benefits to body composition markers such as body weight, fat mass, and abdominal fat, blood pressure, and blood markers of lipid and glucose homeostasis. Future research into TRE and MetS will aim to more closely define optimal formulations of TRE interventions to improve MetS and its components.

Night Shift Work Associates with All-Cause and Cause-Specific Mortality: A Large Prospective Cohort Study

BACKGROUND

Health problems associated with shift work and night shift work are gaining increasing public attention.

OBJECTIVE

To investigate the association between night shift work and the hazard of mortality.

DESIGN

Prospective cohort study.

PARTICIPANTS

A total of 283,579 individuals with paid employment or self-employment aged 37-73 years were included from the UK Biobank with a median follow-up period of 14.0 years.

MAIN MEASURES

Participants were divided into day workers and shift workers, including the frequency of night shifts, to evaluate the association between baseline work schedules and all-cause and cause-specific mortality using the Cox proportional hazards model. Additionally, 75,760 participants with work histories were assessed for the association between average frequency and cumulative years of exposure to night shift work and all-cause and cause-specific mortality.

KEY RESULTS

Compared with that of day workers, the adjusted hazard of all-cause mortality was increased by 12.0% (hazard ratio [HR], 1.12; 95% confidence interval [CI], 1.07-1.18) in shift workers, particularly in those with no or rare night shifts (approximately 16.1%; HR, 1.16; 95% CI, 1.08-1.25) and those with irregular night shifts (approximately 9.2%; HR, 1.09; 95% CI, 1.00-1.19). Moreover, a non-linear relationship was identified between cumulative night shift years and all-cause and cause-specific mortality. Only individuals who worked night shifts for 20-30 years exhibited a substantially increased hazard of all-cause (HR, 1.52; 95% CI, 1.15-2.00) and cardiovascular disease (CVD; HR, 2.08; 95% CI, 1.16-3.71) mortality.

CONCLUSIONS

Shift workers, particularly those with rare or irregular night shifts, exhibited an increased hazard of mortality. Additionally, participants who worked night shifts for 20-30 years exhibited a substantially increased hazard of all-cause and CVD mortality.

Circadian rhythm disruption aggravates alveolar bone loss in rat apical periodontitis

BACKGROUND

Circadian rhythm disruption (CRD) affects the expression levels of a range of biological clock genes, such as brain and muscle ARNT-Like-1 (BMAL1), which is considered to be an important factor in triggering or exacerbating inflammatory response. However, the underlying effect of CRD on the pathogenesis of apical periodontitis, a common oral inflammatory disease, currently remains unknown. Exploring the effects and pathogenic mechanisms of CRD on apical periodontitis will be beneficial in providing new ideas for the prevention and treatment of apical periodontitis.

METHODOLOGY

The cross-sectional study was conducted among patients with apical periodontitis visiting to hospital. Rat models combining CRD and apical periodontitis were constructed, and the destruction of periapical alveolar bone was assessed by Micro-CT, H&E, and TRAP staining assay. Rat periapical alveolar bone tissues were collected for RT-qPCR and immunohistochemistry to further detect the expression of periapical biological clock genes. A model of apical periodontitis was constructed using Bmal1-/- and WT rats to further verify the key role played by Bmal1. Finally, rats raised in CRD environment were intraperitoneally injected with melatonin to restore the circadian rhythm, and the periapical alveolar bone repair was observed by Masson's staining and staining of osteogenic markers (ALP, RUNX2).

RESULTS

A close association between CRD and acute exacerbation of chronic apical periodontitis (CAP) in patients was first found in an epidemiological survey. By constructing animal models of CRD and apical periodontitis, it was found that CRD could aggravate the inflammatory stress of apical periodontitis and even drive the acute exacerbation of CAP. Further investigations suggested that the expression of crucial clock genes, especially Bmal1, were significantly disrupted in the periapical tissue of apical periodontitis. In addition, the periapical tissue from Bmal1 knockout rat displayed stronger inflammatory response and more severe alveolar bone destruction in apical periodontitis. Restoring circadian rhythm by melatonin supplementation could effectively alleviate both the inflammatory response and alveolar bone loss in apical periodontitis.

CONCLUSION

CRD is a novel trigger in aggravating the inflammatory response and alveolar bone loss of apical periodontitis. Melatonin is expected to be used in the dental clinic as an important adjunctive therapy strategy for the healing of periapical tissue in apical periodontitis.

Disruption of circadian rhythm as a potential pathogenesis of nocturia

Increasing evidence suggested the multifactorial nature of nocturia, but the true pathogenesis of this condition still remains to be elucidated. Contemporary clinical medications are mostly symptom based, aimed at either reducing nocturnal urine volume or targeting autonomic receptors within the bladder to facilitate urine storage. The day-night switch of the micturition pattern is controlled by circadian clocks located both in the central nervous system and in the peripheral organs. Arousal threshold and secretion of melatonin and vasopressin increase at night-time to achieve high-quality sleep and minimize nocturnal urine production. In response to the increased vasopressin, the kidney reduces the glomerular filtration rate and facilitates the reabsorption of water. Synchronously, in the bladder, circadian oscillation of crucial molecules occurs to reduce afferent sensory input and maintain sufficient bladder capacity during the night sleep period. Thus, nocturia might occur as a result of desynchronization in one or more of these circadian regulatory mechanisms. Disrupted rhythmicity of the central nervous system, kidney and bladder (known as the brain-kidney-bladder circadian axis) contributes to the pathogenesis of nocturia. Novel insights into the chronobiological nature of nocturia will be crucial to promote a revolutionary shift towards effective therapeutics targeting the realignment of the circadian rhythm.

Six weeks of time-restricted eating improves basal fat oxidation and body composition but not fat oxidation during exercise in young males

BACKGROUND & AIMS

Time-restricted eating (TRE) is a type of intermittent fasting, requiring individuals to limit their eating timeframe to specific hours in the day, while maintaining a fasting period greater than 12 h. Fat oxidation (FOx) is a critical determinant in the pathophysiology of metabolic diseases, with impaired FOx contributing to conditions such as insulin resistance and obesity, whereas enhanced FOx is associated with improved metabolic health. However, the impact of the 16:8 TRE model on FOx remains largely unexplored. The aim of this study was to determine the effect of a 6-week TRE on resting and exercise substrate oxidation, body composition, and blood markers related to metabolic health.

METHODS

Thirty-three healthy, young males (age: 27.5 ± 6 years, body mass: 76.5 ± 8.4 kg, maximal oxygen uptake [V˙O2max]: 43.9 ± 6.6 mL·kg-1·min-1) were assigned to either TRE (n = 16) or control group (n = 17), with efforts to match baseline characteristics, including V˙O2max and body composition. The TRE group followed a 16:8 program for 6 weeks, while controls maintained their existing dietary habits. Body composition, blood glucose, insulin, blood lipids, resting substrate oxidation, and FOx during cycling at 40 % V˙O2max were assessed before and after the 6-week period. Data were analyzed using both intention-to-treat (ITT) and per-protocol approaches.

RESULTS

Thirty-three participants were included in the ITT analysis, while 31 participants were included in the per-protocol analysis. Compared to baseline, results showed a significant difference (p < 0.05) between TRE and control groups in body mass (TRE versus control) (Δ = -2.8 kg versus Δ = 0.7 kg), fat mass (Δ = -1.4 kg versus Δ = 0.4 kg), percent body fat (-1.7 % versus 0.4 %), lean mass (Δ = -1.4 kg versus Δ = 0.3 kg), and visceral adipose tissue mass (Δ = -39.7 g versus Δ = 46.4 g). There was a significant difference between TRE and control groups in resting respiratory exchange ratio (RER, Δ = -0.02 versus Δ = 0.02; p = 0.016), FOx (Δ = 0.33 mg·kg FFM-1·min-1versus Δ = -0.37 mg·kg FFM-1·min-1; p = 0.007), and carbohydrate oxidation (Δ = -0.39 mg·kg FFM-1·min-1versus Δ = 0.45 mg·kg FFM-1·min-1; p = 0.037) after the 6-week period. Exercise substrate oxidation and fasting blood glucose, insulin, triglycerides, total cholesterol, and high-density lipoprotein cholesterol did not significantly change over time in either group (p > 0.05).

CONCLUSIONS

In summary, a 6-week TRE significantly reduces body mass, fat mass, and resting RER as well as increases resting FOx in young, healthy males. However, it does not affect blood markers related to cardiometabolic health or exercise substrate oxidation. This trial was registered at https://clinicaltrials.gov/study/NCT06498102asNCT06498102.

Later eating timing in relation to an individual internal clock is associated with lower insulin sensitivity and affected by genetic factors

BACKGROUND

Although the contribution of the circadian clock to metabolic regulation is widely recognized, the role of eating timing in glucose metabolism and diabetes risk remains insufficiently studied. This study aimed (i) to investigate the link between the eating timing pattern relative to individual clock and glucose homoeostasis and (ii) to explore the contribution of genetic and environmental factors to eating timing parameters.

METHODS

In 92 adult twins (NCT01631123), glycaemic traits were assessed using the oral glucose tolerance test. Parameters of eating timing pattern (eating timing itself, daily calorie distribution, and eating frequency) were extracted from five-day food records. Caloric midpoint defined as the time point at which 50% of daily calories are consumed. Circadian timing of eating was determined as a time interval between the clock time of eating and a corrected midpoint of sleep, a chronotype marker. Heritability of eating timing components was estimated by comparing correlations within monozygotic and dizygotic twin pairs and fitting genetic structural equation models.

FINDINGS

Among components of eating timing, the most associations were found for the circadian time of caloric midpoint (CCM). Later CCM was significantly associated with poorer insulin sensitivity, i.e. with lower ISI Stumvoll (β = 0.304, p = 5.9 × 10-4) and higher HOMA-IR (β = -0.258, p = 0.011) indices, as well as with higher fasting insulin levels (β = -0.259, p = 0.013), even after the model adjustment for sex, age, daily energy intake, and sleep duration. Later CCM also demonstrated robust associations with higher BMI and waist circumference. All eating timing components showed high or moderate heritability and were strongly related to individual sleep timing.

INTERPRETATION

Later eating timing in relation to an individual internal clock is associated with lower insulin sensitivity. Shifting the main calorie intake to earlier circadian times may improve glucose metabolism, but genetic factors could influence the feasibility and effectiveness of eating-timing based interventions. The findings should be investigated in a larger cohort.

FUNDING

This work was supported by the German Research Foundation (DFG RA 3340/4-1 to OP-R, project number 530918029), by the European Association for the Study of Diabetes (Morgagni Prize 2020 to OP-R), and by the German Federal Ministry of Education and Research (BMBF NUGAT 0315424 to AFHP). The DZD is funded by the German Federal Ministry for Education and Research (01GI0925).

An adult clock regulator links circadian rhythms to pancreatic β-cell maturation

The circadian clock attunes metabolism to daily energy cycles, but how it regulates maturation of metabolic tissues is poorly understood. Here we show that DEC1, a clock transcription factor induced in adult islet β cells, coordinates their glucose responsiveness by synchronizing energetic and secretory rhythms. DEC1 binds and regulates maturity-linked genes to integrate insulin exocytosis with energy metabolism, and β-cell Dec1 ablation disrupts their transcription synchrony. Dec1-disrupted mice develop lifelong glucose intolerance and insulin deficiency, despite normal islet formation and intact Clock/Bmal1 genes. Metabolic dysfunction upon β-cell Dec1 loss stems from poor coupling of insulin secretion to glucose metabolism, reminiscent of fetal/neonatal immaturity. We link stunted maturation to a deficit in circadian bioenergetics, prompted by compromised glucose utilization, mitochondrial dynamics, and respiratory metabolism, which is rescued by increased metabolic flux. Thus, DEC1 links circadian clockwork to β-cell metabolic maturation, revealing a hierarchy for how the clock programs metabolic tissue specialization.

Frequent Shifts During Chronic Jet Lag Uncouple Liver Rhythms From the Light Cycle in Male Mice

Circadian disruption is pervasive in modern society and associated with increased risk of disease. Chronic jet lag paradigms are popular experimental tools aiming to emulate human circadian disruption experienced during rotating and night shift work. Chronic jet lag induces metabolic phenotypes tied to liver and systemic functions, yet lack of a clear definition for how rhythmic physiology is impaired under these conditions hinders the ability to identify the underlying molecular mechanisms. Here, we compared 2 common chronic jet lag paradigms and found that neither induced arrythmicity of the liver and each had distinct effects on rhythmicity. Instead, more frequent 8-h forward shifts of the light schedule induced more severe misalignment and non-fasted hyperglycemia. Every other day shifts eventually uncoupled behavioral and hepatic rhythms from the light cycle, reminiscent of free-running conditions. These results point to misalignment, not arrhythmicity, as the initial disturbance tied to metabolic dysfunction in environmental circadian disruption and highlight considerations for the interpretation and design of chronic jet lag studies.

The cyclic metabolic switching theory of intermittent fasting

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

Exercise as a Synchronizer: Effects on Circadian Re-Entrainment of Core Body Temperature and Metabolism Following Light-Dark Cycle Inversion in Mice

Core body temperature (CBT) is a crucial marker of circadian synchrony, reflecting behavioral, metabolic, and environmental adaptations. Disruptions to CBT rhythms, as seen in shift workers or jetlag, indicate desynchronization and can lead to significant health consequences. Exercise is a potent non-photic zeitgeber that may help align circadian rhythms with external cues, but its role in re-entrainment following abrupt phase shifts remains unclear. This study investigated whether voluntary exercise accelerates the re-entrainment of CBT and metabolic rhythms in mice subjected to a 12-h light-dark cycle inversion (LDI). Fifteen C57BL/6 J mice underwent LDI and were divided into two groups. Mice in the control (CTRL) group remained sedentary throughout the experiment while mice in the other group were provided running wheels for 2 weeks after LDI. CBT was continuously monitored using implanted telemetric capsules and metabolic parameters were assessed before and 2 weeks after LDI. Mice that had access to running wheels (RW mice) initially displayed a greater disruption of CBT rhythmicity following LDI, suggesting unstructured physical activity may temporarily exacerbate misalignment, acting as a conflicting signal. Despite this, exercise accelerated recovery, as the phase of the CBT rhythm in RW mice re-aligned to the new light-dark cycle faster than that of the CTRL mice did. The phase of VO₂ rhythms in RW mice also showed trends toward faster realignment. These findings highlight the dual role of exercise as a zeitgeber, capable of both disrupting and accelerating circadian realignment depending on timing. Voluntary exercise may thus serve as an effective intervention to restore circadian synchrony and metabolic homeostasis in individuals experiencing circadian disruptions.

Investigating the modulatory effects of Pu-erh tea on the gut microbiota in ameliorating hyperuricemia induced by circadian rhythm disruption

Circadian rhythm disruption (CRD) can induce a variety of metabolic disorders. Our previous laboratory studies have shown that Pu-erh tea could alleviate CRD-induced syndromes, including obesity, intestinal dysfunction, and tryptophan metabolism disorders. However, its potential protective mechanism against CRD-induced hyperuricaemia remains unclear. In this work, we found that polyphenols of Pu-erh tea were significantly released in the stage of intestinal digestion, which might promote their interaction with gut microbes. Through animal experiments, C57BL6/J mice were given water or different doses of Pu-erh tea for 60 days, followed by a 90-day CRD, the lifestyle of modern individuals who frequently stay up late. Our results indicated that CRD mice exhibited high serum uric acid levels and gut microbiota disorders. Pu-erh tea intake significantly reshaped the gut microbiome, especially increasing the abundance of Bifidobacterium, Akkermansia and Faecalibaculum, and increased the production of short-chain fatty acids (SCFAs), especially acetic acid, which restored the function of the intestinal barrier. This improvement further regulated oxidative stress pathways (NRF2/HO-1), reduced systemic inflammatory response (IL-6, IL-1β, and TNF-α), restored hepatic function (SOD, MOD, CAT, and GSH) and modulated the activity of enzymes related to UA metabolism in the liver (XOD and ADA). Finally, Pu-erh tea intake promoted the excretion of UA and reduced the levels of UA and xanthine in the serum. Moreover, the results of antibiotic experiments showed that the UA improvement effect of Pu-erh tea depended on the existence of the gut microbiota. Collectively, Pu-erh tea intake has the potential to prevent CRD-induced hyperuricaemia by reshaping the gut microbiota.

Circadian clock is critical for fungal pathogenesis by regulating zinc starvation response and secondary metabolism

Circadian clocks are known to modulate host immune responses to pathogen infections, yet their role in influencing pathogen pathogenesis remains unclear. Here, we investigated the role of circadian clocks in regulating the pathogenesis of the fungal pathogen Fusarium oxysporum, which has multiple genes homologous to the Neurospora crassa frq due to gene duplication events, with Fofrq1 being the primary circadian clock gene. The pathogenesis of F. oxysporum in plants is controlled by its circadian clock, with infections causing severe disease symptoms at dawn. Notably, disruption of clock genes dramatically reduces fungal pathogenicity. Circadian clocks regulate the rhythmic expression of several transcription factors, including FoZafA, which enables the pathogen to adapt to zinc starvation within the plant, and FoCzf1, which governs the production of the toxin fusaric acid. Together, our findings highlight the critical roles of circadian clocks in F. oxysporum pathogenicity by regulating zinc starvation response and secondary metabolite production.

Identification of angiotensin II-responsive circadian clock gene expression in adrenal zona glomerulosa cells and human adrenocortical H295R cells

The mammalian circadian timing system is organized in a hierarchy, with the master clock residing in the suprachiasmatic nucleus (SCN) of the hypothalamus and subsidiary peripheral clocks in peripheral tissues. Because of the diversity of peripheral tissues and cell-types in the body, the existence of autonomous clock and identification of its potential entrainment signals need to be empirically defined on a cell type-by-cell type basis. In this study, we characterized the basic circadian clock properties of the adrenal zona glomerulosa cells, or ZG cells. Using isolated adrenal explants from Per2Luc mice, dissociated ZG cells from Per2-dluc rats, and a related human adrenocortical cell line H295R, we showed that ZG cells possess genetically-encoded, self-sustained and cell-autonomous circadian clock. As to the potential entrainment signals, angiotensin II (Ang II) caused phase-dependent phase-shifts of adrenal ZG cells in cultured slices. Ang II treatment also drove initiation (or reset) of circadian clock gene expression in H295R cells with associated immediate up-regulation of PER1 and E4BP4 mRNA expression. We found that the type I Ang II receptor blocker CV11974, one of the most widely used clinical drugs for hypertensive diseases, caused attenuation of the phase resetting of H295R cells. Our in vitro data provide a basis to understand and argue for the adrenal gland ZG cells as a component of autonomous and entrainable peripheral clocks.

Late eating and shortened fasting are associated with higher ultra-processed food intake across all age groups: a population-based study

PURPOSE

Global dietary patterns are increasingly driven by ultra-processed foods-cheap, highly palatable, and ready-to-eat options. Exploring time-related eating patterns and its association with ultra-processed foods could help in intervention efforts, but knowledge on this topic is still limited. This study assessed the association of time-related eating patterns with unprocessed/minimally processed and ultra-processed food consumption across different life stages.

METHODS

Two 24-hour food recalls from a nationally representative sample in Brazil (Brazilian Household Budget Survey, POF, 2017-2018; n = 46,164) were used to estimate tertiles of first and last intake times, eating midpoint, caloric midpoint time, and night fasting (independent variables). All consumed foods were classified according to the Nova classification system, and the outcomes of interest were consumption of unprocessed/minimally processed and ultra-processed foods. Multiple linear regression models were performed for all individuals and stratified for each age group: adolescents (10-19 years, n = 8,469), adults (20-59 years, n = 29,332), and older individuals (≥ 60 years, n = 8,322).

RESULTS

The later tertile of first food intake time, last food intake time, caloric midpoint, and eating midpoint were positively associated with consumption of ultra-processed foods (β = 3.69, 95%CI = 3.04, 4.34; β = 1.89, 95%CI = 1.32, 2.47; β = 5.20, 95%CI = 4.60, 5.81; β = 3.10, 95%CI = 2.49, 3.71, respectively) and negatively associated with consumption of unprocessed or minimally processed foods (β=-2.79, 95%CI=-3.37; -2.22; β=-1.65, 95%CI=-2.24, -1.05; β=-3.94, 95%CI=-4.44, -3.44; β=- 2.35, 95%CI=-2.93, -1.78, respectively) compared to the first "earlier" tertile (reference). An inverse association was found for night fasting (β=-1.74, 95%CI=-2.28, -1.22 and β = 1.52, 95%CI = 0.98, 2.06 for ultra-processed and unprocessed/minimally processed foods, respectively). These associations were consistent across all age groups.

CONCLUSION

Chrononutrition patterns characterized by late intake timing and shortened overnight fasting were associated with higher consumption of ultra-processed foods and lower intake of unprocessed/minimally processed foods across all age groups.

Regulation of testosterone synthesis by circadian clock genes and its research progress in male diseases

ABSTRACT

The circadian clock is an important internal time regulatory system for a range of physiological and behavioral rhythms within living organisms. Testosterone, as one of the most critical sex hormones, is essential for the development of the reproductive system, maintenance of reproductive function, and the overall health of males. The secretion of testosterone in mammals is characterized by distinct circadian rhythms and is closely associated with the regulation of circadian clock genes. Here we review the central and peripheral regulatory mechanisms underlying the influence of circadian clock genes upon testosterone synthesis. We also examined the specific effects of these genes on the occurrence, development, and treatment of common male diseases, including late-onset hypogonadism, erectile dysfunction, male infertility, and prostate cancer.

Early Time-Restricted Eating Improves Weight Loss While Preserving Muscle: An 8-Week Trial in Young Women

Background: Time-restricted eating (TRE) has gained attention as a novel dietary intervention that restricts the daily eating window, potentially offering improved metabolic health and body composition. Nevertheless, whether early TRE (eTRE) or delayed TRE (dTRE) best enhances resistance training (RT) adaptations remains unclear. Methods: In this 8-week randomized study, 24 healthy young women with limited RT experience were assigned into one of three groups: eTRE (an 8:00 AM-2:00 PM feeding window), dTRE (12:00 PM-6:00 PM), or the control (8:00 AM-8:00 PM). Apart from the timing restrictions, no further dietary guidance was provided. All of the participants performed standardized knee-supported push-ups (4 sets × 10 reps, three sessions/week). The primary outcomes included body weight, the thickness of the triceps brachii long head (measured via ultrasound), and push-up endurance. Results: The eTRE group achieved a significant reduction in body weight (-2.61 ± 1.06 kg; p < 0.001), which surpassed the changes observed in both the dTRE (-1.44 ± 1.12 kg) and control (-0.48 ± 0.64 kg) groups. However, no significant between-group differences emerged for muscle thickness or push-up performance. All groups showed comparable improvements in triceps brachii thickness (a 1.36-1.55 mm increase) and push-up endurance (62-74 additional repetitions). Conclusions: Early TRE (8:00 AM-2:00 PM) appears to be more beneficial than delayed TRE (12:00 PM-6:00 PM) for weight management when combined with RT, yet both TRE regimens result in similar improvements in muscle thickness and endurance. These findings suggest that optimizing meal timing in alignment with circadian rhythms may enhance weight control without hindering muscle adaptations, providing a practical approach for individuals seeking to lose weight while preserving or increasing their muscular fitness. Future research involving larger samples and diverse populations is warranted to confirm these results and clarify the underlying metabolic mechanisms.

Glia: the cellular glue that binds circadian rhythms and sleep

Glia are increasingly appreciated as serving an important function in the control of sleep and circadian rhythms. Glial cells in Drosophila and mammals regulate daily rhythms of locomotor activity and sleep as well as homeostatic rebound following sleep deprivation. In addition, they contribute to proposed functions of sleep, with different functions mapping to varied glial subtypes. Here, we discuss recent findings in Drosophila and rodent models establishing a role of glia in circadian or sleep regulation of synaptic plasticity, brain metabolism, removal of cellular debris, and immune challenges. These findings underscore the relevance of glia for benefits attributed to sleep and have implications for understanding the neurobiological mechanisms underlying sleep and associated disorders.

Clinical Chronobiology: Circadian Rhythms in Health and Disease

Circadian rhythms (CRs) are entrainable endogenous rhythms that respond to external stimuli and regulate physiological functions. The suprachiasmatic nucleus (SCN) in the hypothalamus is the mammalian master clock that synchronizes all other tissue-specific peripheral clocks, primarily through gamma-aminobutyric acid (GABA) and vasoactive intestinal polypeptide (VIP). The SCN follows Earth's 24-hour cycle by light entrainment through the retinohypothalamic tract. At the cellular level, the core clock genes CLOCK, BMAL1, PER1-PER3, CRY1, and CRY2 regulate CRs in a negative feedback loop. The circadian disruption of the sleep-wake cycle manifests in at least six distinct clinical conditions. These are the circadian rhythm sleep-wake disorders (CRSWDs). Their diagnosis is made by history, sleep diaries, and actigraphy. Treatment involves a combination of timed light exposure, melatonin/melatonin agonists, and behavioral interventions. In addition, CR disturbances and subsequent misalignment can increase the risk of a variety of illnesses. These include infertility and menstrual irregularities as well as diabetes, obesity, fatty liver disease, and other metabolic syndromes. In addition, a disruption in the gut microbiome creates a proinflammatory environment. CR disturbances increase the risk for mood disorders, hence the utility of light-based therapies in depression. People with neurodegenerative disorders demonstrate significant disturbances in their CRs, and in their sleep-wake cycles. Circadian realignment therapies can also help decrease the symptomatic burden of these disorders. Certain epilepsy syndromes, such as juvenile myoclonic epilepsy (JME), have a circadian pattern of seizures. Circadian disturbances in epilepsy can be both the consequence and cause for breakthrough seizures. The immune system has its own CR. Disturbances in these due to shift work, for instance, can increase the risk of infections. CR disturbances can also increase the risk of cancer by impacting DNA repair, apoptosis, immune surveillance, and cell cycle regulation. Moreover, the timing of chemotherapeutic agents has been shown to increase their therapeutic impact in certain cancers.

Identification of potential susceptibility loci for non-small cell lung cancer through whole genome sequencing in circadian rhythm genes

Lung cancer is a malignant tumor with a high morbidity and mortality rate worldwide, causing an increasing disease burden. Of these, the most common type is non-small cell lung cancer (NSCLC), which accounts for 80-85% of all lung cancer cases. Genetic research is crucial for continuously discovering susceptibility genes related to lung cancer for in-depth study. The role of genetic predisposition in the development of NSCLC, particularly within circadian rhythm pathways known to govern various physiological processes, is increasingly acknowledged. Yet, the association between genetic variants of circadian rhythm-related genes and NSCLC susceptibility among Chinese populations is not fully understood. This study carried out a two-phase (discovery and validation stages) research design to identify genetic variants associated with NSCLC risk within the circadian rhythm pathway. We employed extensive whole-genome sequencing (WGS) for 1,104 NSCLC cases and 9,635 controls. FastGWA-GLMM was used for single-locus risk association analysis of NSCLC, and we screened candidate SNPs in the validation set that comprised 4,444 cases and 174,282 controls from the Biobank Japan Project (BBJ). Furthermore, GCTA-COJO conditional analysis was utilized to confirm SNPs related to NSCLC risk. Finally, potential genetic variations that may regulate gene expression were explored in GTEx and QTLbase. RNA sequencing data were utilized for transcriptomic verification. Our study identified eight candidate SNPs associated with NSCLC susceptibility within the circadian rhythm pathway that met the requirement with P < 0.05 in both the discovery and validation populations. After conditional analysis, five of these SNPs remained. The A allele of CUL1 rs78524436 (ORmeta = 1.18, 95%CI: 1.09-1.29, Pmeta = 7.99e-5) and the A allele of TEF rs9611588 (ORmeta = 1.06, 95%CI: 1.02-1.10, Pmeta = 1.28e-3) were associated with an increased risk of NSCLC. The A allele of FBXL21 rs2069868 (ORmeta = 0.86, 95%CI: 0.80-0.96, Pmeta = 4.78e-4), the T allele of CSNK1D rs147316973 (ORmeta = 0.76, 95%CI: 0.65-0.88, Pmeta = 5.93e-4), and the A allele of RORA rs1589701 (ORmeta = 0.94, 95%CI: 0.91-0.98, Pmeta = 3.40e-3) were associated with a lower risk of NSCLC, separately. The eQTL results revealed an association between RORA rs1589701 and TEF rs9611588 with the expression levels of RORA and TEF, respectively. Transcriptome data indicated that RORA and TEF showed lower expression levels in tumor tissues compared to normal tissues (P < 0.001). Moreover, poorer survival was observed in patients with lower RORA and TEF expressions (log-rank P < 0.05). Our findings spotlight potential susceptibility loci within circadian rhythm pathway genes that modulate NSCLC carcinogenesis, which enriches the understanding of the genetic susceptibility of NSCLC in the Chinese population and provides a more solid basis for exploring the biological mechanism of circadian rhythm genes in NSCLC.

Capsaicin Mitigates Reverbα-Involved Lipid Metabolism Disorder in HepG2 Cells and Obese Mice through a Trpv1-Dependent Mechanism

Capsaicin (CAP), the active component of chili peppers, exerts a range of health benefits, including anti-inflammatory, antitumor, obesity-prevention, metabolic control, and biological rhythm-modulating effects, primarily through the activation of the transient receptor potential vanilloid 1 (TRPV1) receptor. The research explores the role of TRPV1 and its interaction with hepatic circadian clock regulation in modulating lipid metabolism and liver health. The effect of CAP on lipid metabolism and the potential mechanism was examined in HepG2 cells and high-fat, high-sugar diet (HFFD)-induced obese mice. In vitro, CAP (50 μM) decreased lipid droplet overaccumulation (from 152.8 ± 2.30 to 110.13 ± 3.91%), enhanced mitochondrial function (from 57.94 ± 1.93 to 86.74 ± 1.83%), and alleviated circadian desynchrony through a Trpv1-dependent mechanism in HepG2 cells. In vivo, CAP (5 mg/kg) reduced the body weight gain (from 50.61 ± 3.77 to 38.36 ± 2.04%), restored the hepatic circadian rhythm, and modulated the expression of lipid-related genes through the involvement of TRPV1 in mice. This study highlighted the potential of CAP to attenuate Reverbα-mediated lipid metabolic dysfunction through a Trpv1-dependent mechanism, revealing a complex interplay between circadian regulation and lipid metabolism.

Dual-approach co-expression analysis framework (D-CAF) enables identification of novel circadian co-regulation from multi-omic timeseries data

BACKGROUND

The circadian clock is a central driver of many biological and behavioral processes, regulating the levels of many genes and proteins, termed clock controlled genes and proteins (CCGs/CCPs), to impart biological timing at the molecular level. While transcriptomic and proteomic data has been analyzed to find potential CCGs and CCPs, multi-omic modeling of circadian data, which has the potential to enhance the understanding of circadian control of biological timing, remains relatively rare due to several methodological hurdles. To address this gap, a dual-approach co-expression analysis framework (D-CAF) was created to perform co-expression analysis that is robust to Gaussian noise perturbations on time-series measurements of both transcripts and proteins.

RESULTS

Applying this D-CAF framework to previously gathered transcriptomic and proteomic data from mouse macrophages gathered over circadian time, we identified small, highly significant clusters of oscillating transcripts and proteins in the unweighted similarity matrices and larger, less significant clusters of of oscillating transcripts and proteins using the weighted similarity network. Functional enrichment analysis of these clusters identified novel immunological response pathways that appear to be under circadian control.

CONCLUSIONS

Overall, our findings suggest that D-CAF is a tool that can be used by the circadian community to integrate multi-omic circadian data to improve our understanding of the mechanisms of circadian regulation of molecular processes.

The time is now: accounting for time-of-day effects to improve reproducibility and translation of metabolism research

The constant expansion of the field of metabolic research has led to more nuanced and sophisticated understanding of the complex mechanisms that underlie metabolic functions and diseases. Collaborations with scientists of various fields such as neuroscience, immunology and drug discovery have further enhanced the ability to probe the role of metabolism in physiological processes. However, many behaviours, endocrine and biochemical processes, and the expression of genes, proteins and metabolites have daily ~24-h biological rhythms and thus peak only at specific times of the day. This daily variation can lead to incorrect interpretations, lack of reproducibility across laboratories and challenges in translating preclinical studies to humans. In this Review, we discuss the biological, environmental and experimental factors affecting circadian rhythms in rodents, which can in turn alter their metabolic pathways and the outcomes of experiments. We recommend that these variables be duly considered and suggest best practices for designing, analysing and reporting metabolic experiments in a circadian context.

Unraveling the Health Benefits and Mechanisms of Time-Restricted Feeding: Beyond Caloric Restriction

Time-restricted feeding (TRF) is a lifestyle intervention that aims to maintain a consistent daily cycle of feeding and fasting to support robust circadian rhythms. Recently, it has gained scientific, medical, and public attention due to its potential to enhance body composition, extend lifespan, and improve overall health, as well as induce autophagy and alleviate symptoms of diseases like cardiovascular diseases, type 2 diabetes, neurodegenerative diseases, cancer, and ischemic injury. However, there is still considerable debate on the primary factors that contribute to the health benefits of TRF. Despite not imposing strict limitations on calorie intake, TRF consistently led to reductions in calorie intake. Therefore, while some studies suggest that the health benefits of TRF are primarily due to caloric restriction (CR), others argue that the key advantages of TRF arise not only from CR but also from factors like the duration of fasting, the timing of the feeding period, and alignment with circadian rhythms. To elucidate the roles and mechanisms of TRF beyond CR, this review incorporates TRF studies that did not use CR, as well as TRF studies with equivalent energy intake to CR, which addresses the previous lack of comprehensive research on TRF without CR and provides a framework for future research directions.

The Interplay of Genetic Predisposition, Circadian Misalignment, and Metabolic Regulation in Obesity

PURPOSE OF REVIEW

This review explores the complex interplay between genetic predispositions to obesity, circadian rhythms, metabolic regulation, and sleep. It highlights how genetic factors underlying obesity exacerbate metabolic dysfunction through circadian misalignment and examines promising interventions to mitigate these effects.

RECENT FINDINGS

Genome-wide association Studies (GWAS) have identified numerous Single Nucleotide Polymorphisms (SNPs) associated with obesity traits, attributing 40-75% heritability to body mass index (BMI). These findings illuminate critical links between genetic obesity, circadian clocks, and metabolic processes. SNPs in clock-related genes influence metabolic pathways, with disruptions in circadian rhythms-driven by poor sleep hygiene or erratic eating patterns-amplifying metabolic dysfunction. Circadian clocks, synchronized with the 24-h light-dark cycle, regulate key metabolic activities, including glucose metabolism, lipid storage, and energy utilization. Genetic mutations or external disruptions, such as irregular sleep or eating habits, can destabilize circadian rhythms, promoting weight gain and metabolic disorders. Circadian misalignment in individuals with genetic predispositions to obesity disrupts the release of key metabolic hormones, such as leptin and insulin, impairing hunger regulation and fat storage. Interventions like time-restricted feeding (TRF) and structured physical activity offer promising strategies to restore circadian harmony, improve metabolic health, and mitigate obesity-related risks.

Ablation of FAM210A in Brown Adipocytes of Mice Exacerbates High-Fat Diet-Induced Metabolic Dysfunction

Thermogenesis of brown adipose tissue (BAT) provides metabolic benefits against pathologic conditions, such as type 2 diabetes, obesity, cardiovascular disease, and cancer. The thermogenic function of BAT relies on mitochondria, but whether mitochondrial remodeling is required for the beneficial effects of BAT remains unclear. We recently identified FAM210A as a BAT-enriched mitochondrial protein essential for cold-induced thermogenesis through the modulation of OPA1-dependent cristae remodeling. Here, we report a key role of FAM210A in the systemic response to a high-fat diet (HFD). We discovered that an HFD suppressed FAM210A expression, associated with excessive OPA1 cleavage in BAT. Ucp1-Cre-driven BAT-specific Fam210a knockout (Fam210aUKO) similarly elevated OPA1 cleavage, accompanied by whitening of BAT. When subjected to an HFD, Fam210aUKO mice gained similar fat mass as sibling control mice but developed glucose intolerance, insulin resistance, and liver steatosis. The metabolic dysfunction was associated with overall increased lipid content in both the liver and BAT. Additionally, Fam210aUKO leads to inflammation in white adipose tissue. These data demonstrate that FAM210A in BAT is necessary for counteracting HFD-induced metabolic dysfunction but not obesity.

ARTICLE HIGHLIGHTS

FAM210A regulates cold-induced mitochondrial remodeling through control of OPA1 cleavage, but whether it also plays a role in high-fat diet (HFD)-induced cristae remodeling is unknown. We asked if an HFD would alter the FAM210A level and OPA1 cleavage in brown adipose tissue (BAT) and how FAM210A loss of function would affect diet-induced obesity in mice. We found that an HFD diminished FAM210A expression and accelerated OPA1 cleavage in BAT, and Fam210a knockout exacerbated HFD-induced whitening of BAT, cold intolerance, liver steatosis, white adipose tissue inflammation, and metabolic dysfunction. Our work reveals a physiologic role of FAM210A-mediated BAT mitochondrial remodeling in systemic adaptation to an HFD and suggests that BAT mitochondria may be targeted to treat diet-induced metabolic dysfunction.

Neuropeptide-Dependent Spike Time Precision and Plasticity in Circadian Output Neurons

Circadian rhythms influence various physiological and behavioral processes such as sleep-wake cycles, hormone secretion, and metabolism. In Drosophila, an important set of circadian output neurons is called pars intercerebralis (PI) neurons, which receive input from specific clock neurons called DN1. These DN1 neurons can further be subdivided into functionally and anatomically distinctive anterior (DN1a) and posterior (DN1p) clusters. The neuropeptide diuretic hormones 31 (Dh31) and 44 (Dh44) are the insect neuropeptides known to activate PI neurons to control activity rhythms. However, the neurophysiological basis of how Dh31 and Dh44 affect circadian clock neural coding mechanisms underlying sleep in Drosophila is not well understood. Here, we identify Dh31/Dh44-dependent spike time precision and plasticity in PI neurons. We first find that a mixture of Dh31 and Dh44 enhanced the firing of PI neurons, compared to the application of Dh31 alone and Dh44 alone. We next find that the application of synthesized Dh31 and Dh44 affects membrane potential dynamics of PI neurons in the precise timing of the neuronal firing through their synergistic interaction, possibly mediated by calcium-activated potassium channel conductance. Further, we characterize that Dh31/Dh44 enhances postsynaptic potentials in PI neurons. Together, these results suggest multiplexed neuropeptide-dependent spike time precision and plasticity as circadian clock neural coding mechanisms underlying sleep in Drosophila.

The associations between evening eating and quality of energy and macronutrients and obesity: the National Health and Nutrition Examination Survey (NHANES), 2003-2016

BACKGROUND

This study aimed to investigate the associations between evening eating and quality of energy and macronutrients and obesity among U.S. adults.

SUBJECTS/METHODS

This study adopted the data from the National Health and Nutrition Examination Survey (2003-2016), which involved a total of 27,911 participants. The differences in the ratios of energy and macronutrients with it is subgroups at dinner versus breakfast (ΔRatio) were categorized into quartiles. The differences in the consumption of 17 types of food at dinner versus breakfast (ΔFoods) were considered as continuous variables. Body mass index (BMI) and waist circumference (WC) were used to define general obesity (30.0 ≤ BMI < 40.0), morbid obesity (BMI ≥ 40.0), and abdominal obesity (WC > 102 cm for men or WC > 88 cm for women). Multiple logistic and linear regression models were developed.

RESULTS

After a variety of covariates were adjusted, participants in the highest quartile (higher energy/macronutrient intake at dinner than breakfast) of the ΔRatio in terms of energy were positively associated with morbid obesity compared with those in the lowest quartile (ORΔRatio of energy 1.27; 95% CI 1.01;1.61) from fat (ORΔRatio of fat 1.27, 95% CI 1.01;1.60); saturated fatty acids(ORΔRatio of SFA 1.27, 95% CI 1.01;1.59) and unsaturated fatty acids (ORΔRatio of USFA 1.28, 95% CI 1.02;1.5). The highest quartile of the ΔRatio of low-quality carbohydrates was associated with increased odds of abdominal obesity (ORΔRatio of low-quality carbohydrates 1.16; 95%CI 1.03-1.31). Moreover, the ΔRatio of low-quality carbohydrates was significantly positively associated with BMI (coefficient: 0.562, 95% CI: 0.217-0.907). ΔFoods, including whole fruits, other starchy vegetables, added sugars, poultry, dairy, and nuts, were positively associated with obesity.

CONCLUSIONS

In conclusion, with this nationally representative sample of U.S adults, this study demonstrated that excessive intake of energy at dinner than breakfast during a day was associated with a greater risk of obesity, mainly from low-quality carbohydrates, fat, SFAs, and USFA. This study emphasized the importance of diet quality and evening eating in the prevention of obesity.

The efficacy of DASH combined with time-restricted feeding (16/8) on metabolic associated fatty liver disease management: a randomized controlled trial

Recent studies have utilized time-restricted feeding (16/8) (TRF) and dietary approaches to stop hypertension separately to manage metabolic-associated fatty liver disease (MAFLD); however, the effectiveness of combining these two approaches has not been investigated. The objective of this study was to examine the impact of TRF in conjunction with a DASH diet on various factors related to MAFLD. A 12-week randomized controlled trial was conducted to assess the impact of TRF (16/8), along with a DASH diet, compared with a control diet based on standard meal distribution, in patients with MAFLD. An investigation was conducted to examine alterations in anthropometric indices, as well as liver parameters, serum metabolic indices, and an inflammatory marker. The TRF plus DASH diet reduced body mass index (p = 0.03), abdominal circumference (p = 0.005), controlled attenuation parameter (CAP) (p < 0.001), alanine aminotransferase (p = 0.039), and aspartate aminotransferase (0.047) compared to the control group. The levels of insulin and homeostasis model assessment of insulin resistance reduced in both groups significantly (P < 0.05). In MAFLD patients, TRF (16/8) in combination with a DASH diet is superior to a low-calorie diet in promoting obesity indices, and hepatic steatosis and fibrosis. Further long-term investigations are needed to draw definitive conclusions.

A curated tissue-specific proteome, phosphoproteome, and kinome map of Drosophila melanogaster with an integrated outlook in circadian physiology

The fruit fly Drosophila melanogaster is a simple multicellular model system widely used in biomedical research. Here, we aimed to curate a comprehensive tissue and organ-specific proteome, phosphoproteome, and kinome atlas of D. melanogaster. Using information from published literature and databases, we have systematically curated the protein expression profiles, phosphorylation patterns, and the associated kinases and phosphatases in 11 tissue types across the different developmental stages and mature D. melanogaster and its derived cell lines. Gene annotation and pathway enrichment analysis were performed using the DAVID. Protein-protein interaction analysis was carried out using STRING, BioGrid, OmniPath, and InWeb-IM. Drosophila kinase and phosphatase gene orthologs in humans and mice were identified through the FlyBase database, utilizing the DRSC integrative ortholog prediction tool. We mapped a total of 18,377 proteins, 9021 phosphoproteins, 433 kinases, and 141 phosphatases in D. melanogaster. Subsequent categorization of the proteins into different tissue types indicated the enrichment of some tissue-specific pathways and expression clusters. We identified 295 and 289 Drosophila kinase orthologs in humans and mice through an ortholog screening. In the rhythmicity analysis, we observed 24-hour periodicity in 5289 transcripts, 678 proteins, 437 phosphoproteins, 166 kinases, and 89 phosphatases. The findings of our study are integrated as a convenient resource for understanding the proteome-level organizations in Drosophila, their oscillating expression, and their tissue-specific roles in maintaining cellular and physiological functions. We anticipate that this study will help to enhance the systems-level analysis of D. melanogaster as a model organism.

Proposal for delta check limits of frequently requested hormones using real-world data

Introduction

Research on delta check limits (DCLs) for hormones is limited, yet some laboratories apply arbitrary DCLs. We aimed to propose DCLs for commonly requested hormones.

Materials and methods

This study analyzed 59,657 paired results for adrenocorticotropic hormone (ACTH), cortisol, parathyroid hormone (PTH), prolactin, insulin, testosterone, and thyroglobulin from five Korean university hospitals. Delta check limits were established using the absolute delta difference (absDD) and absolute delta percent change (absDPC) with 5% cutoff for inpatients/emergencies (IE), outpatients (O) and both (combined; mean of them). Proportions outside the DCLs were compared across groups.

Results

Using absDD and absDPC, each group's DCLs showed 4.3% to 6.4% of values outside the DCLs, aligning with the 5% cutoff (excluding group IE for insulin, testosterone, and thyroglobulin due to < 1000 data pairs). Delta check limits of absDD differed between groups for ACTH, cortisol, PTH, and prolactin, while for absDPC, differences were seen only for ACTH and prolactin. Cross-validation revealed IE and O groups differed outside DCLs of absDD for ACTH, cortisol, and PTH, but only ACTH with absDPC. Combined DCLs of absDD showed ACTH and cortisol exceeded limits in 7.2% and 9.0% in IE, but only 2.6% and 0.6% in O. With absDPC, ACTH differed (10.4% in IE, 2.8% in O), while cortisol, PTH, and prolactin ranged from 4.0% to 6.1%.

Conclusions

Combined DCLs of absDPC are recommended for cortisol, PTH, and prolactin, while ACTH requires separate DCLs on clinical settings. These DCLs from real-world data provide a foundation for establishing DCLs of hormones in clinical laboratories.

Time-restricted feeding alleviates arthritis symptoms augmented by high-fat diet

Rheumatoid arthritis (RA) affects approximately 1% of the global population. Its hallmark symptoms include severe pain and joint stiffness, which significantly diminish life quality. RA's development is influenced by multiple factors including unhealthy lifestyle habits. Calorie-rich diets, particularly those high in fat and resulting in obesity, are associated with RA and exacerbate its symptoms. Consequently, dietary modifications are recommended as a complementary treatment. However, adherence is often low due to the restrictive changes required in nutrient composition or caloric intake. Our previous findings indicate that time-restricted feeding (TRF) benefits leukocyte rhythm and mitigates autoimmune responses. In this study we explored the impact of TRF on the severity of K/BxN serum-transfer arthritis (STA) in mice subjected to high-fat diet. Three feeding schedules were implemented: a control (Ctrl) with constant access to standard chow, a high-fat diet group (HF) with ad libitum food access, and a high-fat TRF group (HF-TRF) with a 10-hour feeding window during the active phase. After four weeks of conditioning, STA was induced. Although macroscopic markers of inflammation did not differ between the Ctrl and HF groups, histological analysis revealed increased inflammation in HF mice, including expanded edema, pannus formation, bone erosion, elevated synovial neutrophil infiltration and serum leptin levels. Importantly, all these inflammatory markers were significantly reduced in the HF-TRF group, along with synovial IL-1β and monocyte/macrophage counts. Our results indicate that TRF can diminish the impact of a high-fat diet on STA severity, potentially serving as a preventive method and a sustainable therapeutic support for RA management.

Design, synthesis and in vitro evaluations of new cyclotriphosphazenes as safe drug candidates

Although it is possible to discover new drug candidate molecules using in silico approaches, chemical synthesis followed by screening of their functions is still at the center of bioactive molecule discovery. While determining the potential effects of compounds on target signaling molecules or pathways, assessing their effects on the circadian rhythm is also very important for determining the efficacy of drug candidates because they control most of the signaling pathways. Herein, new members of the biocompatible cyclotriphosphazene family were prepared, and their in vitro biological activities and effects on circadian rhythm were evaluated for the first time. In particular, new cyclotriphosphazene derivatives carrying morpholine, thiomorpholine and triazole groups were designed and synthesized, and their chemical structures were characterized using appropriate spectroscopic methods. Cellular toxicity analyses of the compounds were performed using different biological methods, such as determination of IC50 values, calculation of population doubling times, and colony formation patterns. Subsequently, the effects of the compounds on the cell cycle were analyzed using the flow cytometry technique. Finally, the effects of the synthesized compounds on circadian rhythm were determined using a real-time bioluminescence approach. Based on these studies, it was determined that some compounds demonstrated varying degrees of antiproliferative activity, with the most potent compounds causing G2/M phase arrest. Additionally, most derivatives had no adverse effects on the circadian rhythm, indicating their potential for safe therapeutic application in targeting cell proliferation. Furthermore, an important pharmacological characteristic of the drug candidate molecules, namely, membrane permeability in terms of log P values, was assessed. In conclusion, these novel cyclotriphosphazene-based compounds are a class of circadian rhythm-safe drug candidate compounds.

The circadian clock affects starvation resistance through the pentose phosphate pathway in silkworm, Bombyx mori

Disruption of the circadian clock can affect starvation resistance, but the molecular mechanism is still unclear. Here, we found that starvation resistance was significantly reduced in the core gene BmPer deficient mutant silkworms (Per-/-), but the mutant's starvation resistance increased with larval age. Under natural physiological conditions, the weight of mutant 5th instar larvae was significantly increased compared to wild type, and the accumulation ability of triglycerides and glycogen in the fat bodies was upregulated. However, under starvation conditions, the weight consumption of mutant larvae was increased and cholesterol utilization was intensified. Transcriptome analysis showed that beta-oxidation was significantly upregulated under starvation conditions, fatty acid synthesis was inhibited, and the expression levels of genes related to mitochondrial function were significantly changed. Further investigations revealed that the redox balance, which is closely related to mitochondrial metabolism, was altered in the fat bodies, the antioxidant level was increased, and the pentose phosphate pathway, the source of reducing power in cells, was activated. Our findings suggest that one of the reasons for the increased energy burden observed in mutants is the need to maintain a more robust redox balance in metabolic tissues. This necessitates the diversion of more glucose into the pentose phosphate pathway to ensure an adequate supply of reducing power.

Chronodisruption that dampens output of the central clock abolishes rhythms in metabolome profiles and elevates acylcarnitine levels in the liver of female rats

AIM

Exposure to light at night and meal time misaligned with the light/dark (LD) cycle-typical features of daily life in modern 24/7 society-are associated with negative effects on health. To understand the mechanism, we developed a novel protocol of complex chronodisruption (CD) in which we exposed female rats to four weekly cycles consisting of 5-day intervals of constant light and 2-day intervals of food access restricted to the light phase of the 12:12 LD cycle.

METHODS

We examined the effects of CD on behavior, estrous cycle, sleep patterns, glucose homeostasis and profiles of clock- and metabolism-related gene expression (using RT qPCR) and liver metabolome and lipidome (using untargeted metabolomic and lipidomic profiling).

RESULTS

CD attenuated the rhythmic output of the central clock in the suprachiasmatic nucleus via Prok2 signaling, thereby disrupting locomotor activity, the estrous cycle, sleep patterns, and mutual phase relationship between the central and peripheral clocks. In the periphery, CD abolished Per1,2 expression rhythms in peripheral tissues (liver, pancreas, colon) and worsened glucose homeostasis. In the liver, it impaired the expression of NAD+, lipid, and cholesterol metabolism genes and abolished most of the high-amplitude rhythms of lipids and polar metabolites. Interestingly, CD abolished the circadian rhythm of Cpt1a expression and increased the levels of long-chain acylcarnitines (ACar 18:2, ACar 16:0), indicating enhanced fatty acid oxidation in mitochondria.

CONCLUSION

Our data show the widespread effects of CD on metabolism and point to ACars as biomarkers for CD due to misaligned sleep and feeding patterns.

Network analysis of the hair-based nine hormones from four neuroendocrine systems

INTRODUCTION

The stress response maintains the homeostasis of the body's internal environment and normal physiological activities, involving several neuroendocrine systems, such as the HPA axis, the HPG axis, the endocannabinoid system, and the melatonin system. However, studies on the intricate interactions among the four neuroendocrine systems are lacking, and it is not clear how these interactions are affected by demographic variables. The aim of this study was to investigate the network characteristics of hormonal networks comprising nine hormones from four neuroendocrine systems and how they were affected by demographic variables.

METHODS

252 healthy current students were recruited from Southeast University, China. The concentrations of nine hormones in their hair were measured by LC/MS methods, and hormonal network was constructed. Network analysis was used to characterize the interrelationships between hormones or neuroendocrine systems, central hormones, bridge hormones, hormonal network characteristics, and their changes in response to demographic variables.

RESULTS

Complex interactions between the HPA axis, the HPG axis, the ECS and the melatonin system formed a sparse and stable network, with cortisol and cortisone being the central hormones and melatonin as the bridge hormone. Demographic variables did not affect the overall characteristics of the network or the central hormone, but a number of specific connections in the network changed and the bridge hormones became cortisone and progesterone.

CONCLUSION

The interactions between the four stress-related neuroendocrine systems were relatively stable and were centered and initiated by the HPA axis. Demographic variables did not affect the overall structure of the network, but influenced local features of the network, such as edge weights and bridge centrality.

Understanding the intricacies of cellular mechanisms in remyelination: The role of circadian rhythm

The term "circadian rhythm" refers to the 24-h oscillations found in various physiological processes in organisms, responsible for maintaining bodily homeostasis. Many neurological diseases mainly involve the process of demyelination, and remyelination is crucial for the treatment of neurological diseases. Current research mainly focuses on the key role of circadian clocks in the pathophysiological mechanisms of multiple sclerosis. Various studies have shown that the circadian rhythm regulates various cellular molecular mechanisms and signaling pathways involved in remyelination. The process of remyelination is primarily mediated by oligodendrocyte precursor cells (OPCs), oligodendrocytes, microglia, and astrocytes. OPCs are activated, proliferate, migrate, and ultimately differentiate into oligodendrocytes after demyelination, involving many key signaling pathway and regulatory factors. Activated microglia secretes important cytokines and chemokines, promoting OPC proliferation and differentiation, and phagocytoses myelin debris that inhibits remyelination. Astrocytes play a crucial role in supporting remyelination by secreting signals that promote remyelination or facilitate the phagocytosis of myelin debris by microglia. Additionally, cell-to-cell communication via gap junctions allows for intimate contact between astrocytes and oligodendrocytes, providing metabolic support for oligodendrocytes. Therefore, gaining a deeper understanding of the mechanisms and molecular pathways of the circadian rhythm at various stages of remyelination can help elucidate the fundamental characteristics of remyelination and provide insights into treating demyelinating disorders.

Short-Term Fasting Induces Hepatocytes' Stress Response and Increases Their Resilience

Fasting leads to a range of metabolic adaptations that have developed through evolution, as humans and other mammals have unequal access to food over the circadian cycle and are therefore adapted to fasting and feeding cycles. We have investigated the role of a single fasting episode in rats in triggering the stress response of liver hepatocytes. Since the stress responses were observed in both animals and isolated cells, we investigated whether the effects of the animal stressor could persist in the cells after isolation. By measuring staurosporine-induced apoptosis, stress signalling, and oxidative and antioxidant responses in hepatocytes from fasted and ad libitum-fed animals, we found that only fasting animals elicited a stress response that prevented caspase-9 activation and persisted in isolated cells. The addition of glucose oxidase, a hydrogen peroxide-producing enzyme, to the cells from ad libitum-fed animals also led to a stress response phenotype and prevented the activation of caspase-9. A single fasting episode thus leads to a stress response in normal hepatocytes, with hydrogen peroxide as a second messenger that reduces the initiation of apoptosis. This finding is the first characterisation of a mechanism underlying the effects of fasting and provides a basis for the development of methods to increase the resilience of cells. These findings need to be taken into account when interpreting the results obtained in animal and cell research models to account for the effects of overnight fasting used in many laboratory protocols. The research results also form the basis for the development of clinical applications to increase the resistance of transplants and to improve the fitness of hepatocytes under acute stress conditions in liver and some metabolic diseases.

Circadian metabolic adaptations to infections

Circadian clocks are biological oscillators that evolved to coordinate rhythms in behaviour and physiology around the 24-hour day. In mammalian tissues, circadian rhythms and metabolism are highly intertwined. The clock machinery controls rhythmic levels of circulating hormones and metabolites, as well as rate-limiting enzymes catalysing biosynthesis or degradation of macromolecules in metabolic tissues, such control being exerted both at the transcriptional and post-transcriptional level. During infections, major metabolic adaptation occurs in mammalian hosts, at the level of both the single immune cell and the whole organism. Under these circumstances, the rhythmic metabolic needs of the host intersect with those of two other players: the pathogen and the microbiota. These three components cooperate or compete to meet their own metabolic demands across the 24 hours. Here, we review findings describing the circadian regulation of the host response to infection, the circadian metabolic adaptations occurring during host-microbiota-pathogen interactions and how such regulation can influence the immune response of the host and, ultimately, its own survival.This article is part of the Theo Murphy meeting issue 'Circadian rhythms in infection and immunity'.

The effects of intermittent fasting on antioxidant and inflammatory markers and liver enzymes in postmenopausal, overweight and obese women with rheumatoid arthritis: a randomized controlled trial

Rheumatoid arthritis (RA) is a chronic inflammatory disorder affecting postmenopausal women. This study investigated the effects of intermittent fasting (IF) on antioxidant and inflammatory markers and liver enzymes in postmenopausal, overweight and obese women with RA. This 8-week randomized controlled trial included 44 postmenopausal women with RA divided into an intervention group following a 16:8 IF diet and a control group maintaining their usual diet and received recommendations for healthy eating. Inflammatory indices, oxidative stress markers, and liver enzymes were measured at baseline and post intervention. The IF group showed significant decreases in serum malondialdehyde (MDA) levels (P = 0.02) and neutrophil-to-lymphocyte ratio (P = 0.018) and increased catalase levels (P = 0.004) compared to the control group. Liver enzymes aspartate transaminase (AST) and alanine transaminase (ALT) also decreased significantly in the IF group (P = 0.02 and P = 0.03, respectively). No significant differences were observed in the other measured parameters between groups. In conclusion, the 16:8 IF diet demonstrated beneficial effects on some oxidative stress markers, inflammatory indices, and liver enzymes in postmenopausal, overweight, and obese women with RA. These findings suggest that IF may be an effective non-pharmacological intervention for managing RA in this population, potentially addressing both primary disease symptoms and associated metabolic complications. Further research is needed to elucidate the long-term effects and mechanisms of IF in the management of RA.