Search Results (429)

Modern genetic selection for high productivity has created a physiological conflict in ruminants, where the metabolic demands of lactation compete directly with the energy requirements of reproduction. This review provides a mechanistic synthesis of how key nutritional factors modulate the endocrine and cellular pathways governing reproductive success in cattle and sheep. Negative energy balance (NEB), characteristic of the early postpartum period, suppresses the hypothalamic–pituitary–gonadal (HPG) axis by impairing the pulsatile secretion of gonadotropin-releasing hormone (GnRH) and luteinizing hormone (LH), mediated through reduced kisspeptin signaling, growth hormone (GH) resistance, and decreased circulating insulin, insulin-like growth factor-1 (IGF-1), and leptin. At the macronutrient level, excess rumen-degradable protein elevates blood urea nitrogen and impairs the uterine environment, while omega-3 polyunsaturated fatty acids inhibit prostaglandin F2α synthesis to support corpus luteum maintenance. At the micronutrient level, selenium, copper, and zinc are essential antioxidant cofactors protecting gametes and embryos from oxidative stress, while vitamins A, D, and E regulate gene expression in reproductive tissues. Furthermore, maternal nutrition during critical gestational windows programs the reproductive capacity of offspring through epigenetic modifications, with profound implications for long-term herd fertility. Understanding these nutritional–reproductive interactions is crucial for developing precision feeding strategies that optimize herd fertility, improve animal welfare, and ensure the economic sustainability of livestock management. A thorough understanding of these nutritional–reproductive interactions is essential for developing precision feeding strategies that optimize fertility in high-producing ruminants. Full article

Obesity is a complex metabolic disorder associated with dyslipidemia, insulin resistance, and hepatic steatosis. Given its multifactorial nature, multi-component therapeutic strategies have attracted increasing interest, particularly herbal formulations containing diverse bioactive compounds. This study investigated the anti-obesity and hepatoprotective effects of a mixed herbal extract, JH01, composed of Curcuma longa, Achyranthes bidentata, and Polygonum multiflorum, using a screening-based analytical approach combined with experimental validation. Individual herbal extracts and their mixture were screened at 100 and 500 μg/mL in 3T3-L1 adipocytes. Based on superior anti-adipogenic efficacy, JH01 was selected for further study. Its effects were evaluated in vitro by Oil Red O staining and quantitative real-time PCR analysis of adipogenic genes, and in vivo using a high-fat diet (HFD)-induced obese mouse model, assessing body weight, serum lipid profiles, liver function markers, adipokine levels, and hepatic histology. JH01 showed markedly stronger inhibition of lipid accumulation than individual herbal components. JH01 significantly suppressed adipocyte differentiation and downregulated PPARγ, C/EBPα, and SREBP-1 expression in 3T3-L1 cells. Furthermore, JH01 modulated inflammatory cytokines and adipokine levels, as evidenced by reduced TNF-α, IL-6, and IL-1β levels and increased adiponectin levels. In HFD-fed mice, JH01 reduced body weight gain, serum triglyceride and total cholesterol levels, improved ALT and AST levels, decreased leptin concentrations, and attenuated hepatic steatosis. JH01 exerts potent anti-obesity and hepatoprotective effects through coordinated regulation of lipid metabolism and adipogenesis, supporting its potential as a multi-herbal therapeutic strategy for obesity-related metabolic disorders. Full article

Background: Obesity is a chronic metabolic disease that has emerged as a major global public health concern. Obesity complications refer to a range of metabolic, neurological and behavioral disorders. Complex interaction mechanisms exist between obesity and the brain, including neuroendocrine regulation, center inflammatory responses, the gut–brain axis, and obesity-related cognitive impairment. Polyphenols are naturally occurring bioactive compounds widely found in plants. Recent research indicates that polyphenols may modulate the brain through multiple pathways, thereby ameliorating obesity complications. However, no data set available to summarize neuroregulatory effects of dietary polyphenols on obesity complication. Methods: The latest data available were collected to review research progress focusing on neuroregulatory roles of polyphenols on obesity complication. Results: This review summarizes the interaction between obesity and the brain and further explores the effects of polyphenols on obesity-related neurological disorders, with particular emphasis on their roles in appetite regulation, central neuroinflammation, brain leptin and insulin resistance, gut–brain axis modulation, and cognitive improvement. Finally, future perspectives are discussed. Conclusions: This paper may provide a new theoretical support and research direction for the potential of polyphenols against obesity-related neurological complications. Full article

The relationship between epilepsy, obesity, and metabolic syndrome (MetS) has emerged as a rapidly evolving area of neurobiology inquiry. Emerging evidence suggests that epilepsy extends beyond neuronal hyperexcitability, reframing it as a systemic condition characterized by significant metabolic dysregulation. Converging supports a bidirectional relationship while seizures, antiseizure medications (ASM), and neuroinflammation induce exacerbate potentiate epileptogenesis through shared molecular pathways. At the cellular level, chronic epileptic activity induces oxidative stress, mitochondrial dysfunction, and the activation of microglia and astrocytes. This, in turn, leads to the release of pro-inflammatory cytokines including TNF-α, IL-1β, and IL-6. These mediators traverse the blood-brain barrier (BBB), subsequently modifying insulin signaling, and disrupting glucose homeostasis, which collectively fosters a pro-inflammatory and insulin-resistant environment. Furthermore, antiseizure medications such as valproate can exacerbate these effects by directly impairing insulin receptor signaling and altering adipokine production, ultimately contributing to weight gain and systemic metabolic dysregulation. Obesity and MetS induce neuroinflammatory and excitotoxic states that promote seizure onset via leptin resistance, reduced adiponectin levels, and compromised AMP-activated protein kinase (AMPK) signaling. Emerging evidence emphasizes the gut-brain axis as a crucial regulator in this reciprocal interaction. Dysbiosis, altered microbial metabolites (e.g., short-chain fatty acids), and heightened intestinal permeability facilitate systemic inflammation and BBB disruption, enhancing neuronal excitability. Insulin resistance in the brain disrupts synaptic transmission, impairs mitochondrial biogenesis, and compromises redox equilibrium, perpetuating a pathological cycle linking metabolic stress to epileptic activity. This review synthesizes the cellular, molecular, and systemic pathways connecting epilepsy, obesity, and MetS, and proposes that epilepsy be reconceptualized as a neuro-metabolic disorder. Insights into these convergent pathways provide a rationale for novel therapeutic strategies that simultaneously target seizure control and metabolic regulation, encompassing microbiota modulation, antioxidant therapy, and insulin-sensitizing interventions with the overarching aim of restoring neuro-metabolic homeostasis. Full article

Obesity represents a heterogeneous metabolic disorder characterized by substantial interindividual variation in inflammatory status, insulin sensitivity, and cardiometabolic risk. Traditional anthropometric measures fail to capture this metabolic diversity, limiting risk stratification and personalized intervention strategies. This review critically examines nutritional and metabolic biomarkers that reflect the physiological dysregulation underlying obesity, including adipokines (leptin, adiponectin, resistin), inflammatory markers (C-reactive protein, interleukin-6, TNF-α), insulin resistance indices (HOMA-IR, fasting insulin, HbA1c), and lipid metabolism indicators (LDL cholesterol, triglycerides, HDL cholesterol, and liver enzymes such as ALT and GGT). Among these, elevated CRP, reduced adiponectin, and increased HOMA-IR have demonstrated the strongest clinical utility for early metabolic risk identification. We further evaluate emerging biomarkers—including circulating microRNAs, gut microbiota-derived metabolites (short-chain fatty acids, TMAO, lipopolysaccharides), and bile acid profiles—which offer additional mechanistic insight into diet–microbiome–host interactions. We systematically assess the mechanistic basis, clinical relevance, and nutritional modulation of each biomarker class, emphasizing how dietary composition—particularly fatty acid quality, fiber intake, and overall dietary patterns such as the Mediterranean diet—influences biomarker profiles and metabolic outcomes. Furthermore, we explore how biomarker-based phenotyping enables precision nutrition approaches by identifying individuals most likely to benefit from specific dietary interventions. Integration of multi-biomarker panels with clinical and genetic data holds promise for advancing from population-based dietary guidelines toward individualized nutrition strategies that optimize metabolic health and prevent obesity-related complications. Future research should prioritize validating biomarker-guided intervention frameworks, establishing standardized thresholds across diverse populations, and developing clinically implementable tools for personalized nutritional medicine. Full article

Background/Objectives: Polycystic ovary syndrome (PCOS) is a prevalent endocrine disorder characterized by reproductive and metabolic dysfunction. Vitamin D deficiency is common in women with PCOS and is linked to adverse metabolic and reproductive outcomes. However, the role of vitamin D supplementation in managing PCOS remains unclear due to the heterogeneous evidence available. This systematic review aimed to synthesize both observational and interventional studies to assess the association between vitamin D levels and PCOS, focusing on prevalence, metabolic outcomes, and reproductive parameters. Methods: A comprehensive search of PubMed, Web of Science, Scopus, and Embase was conducted in October 2025, identifying studies published between January 2000 and October 2025. Eligible studies included observational studies and randomized controlled trials (RCTs) evaluating serum 25-hydroxyvitamin D [25(OH)D] levels and/or the effects of vitamin D supplementation in women with PCOS. Studies were included if they used recognized diagnostic criteria for PCOS or sufficient diagnostic details to confirm the condition. Two reviewers independently performed screening, data extraction, and quality assessment according to PRISMA 2020 guidelines. Results: Eleven studies (nine RCTs, two observational) encompassing 1063 women with PCOS met the inclusion criteria. Observational studies demonstrated inverse associations between serum 25(OH)D levels and insulin resistance, body mass index (BMI), and leptin, but not with total testosterone. RCTs showed modest and inconsistent improvements in insulin sensitivity, with effects more apparent in some trials enrolling vitamin D-deficient women. Reproductive benefits (cycle regularity/ovulation) were observed only in selected trials, generally with small samples and short follow-up. Conclusions: Vitamin D deficiency is common in women with PCOS and correlates with metabolic and reproductive dysfunction. While vitamin D supplementation shows variable effects, it should not be considered a stand-alone therapy for PCOS. Correction of deficiency may complement existing treatments, but evidence remains insufficient to support routine vitamin D supplementation for fertility outcomes in PCOS. Full article

Adipocytes produce the hormone leptin, a hormone that links energy availability to reproductive function by permitting activation of the hypothalamic–pituitary–gonadal (HPG) axis. Loss-of-function mutations in the long leptin receptor isoform (LEPRb) disrupt intracellular signaling pathways, including the Janus kinase 2 (JAK2)/signal transducer and activator of transcription 3 (STAT3), phosphoinositide 3-kinase (PI3K), and mitogen-activated protein kinase (MAPK) pathways, resulting in central leptin resistance and impaired neuroendocrine control of reproduction. Evidence from human monogenic obesity syndromes, animal models, and neuroendocrine studies indicates that LEPRb mutations disrupt hypothalamic circuitry upstream of gonadotropin-releasing hormone (GnRH) neurons, impairing GnRH pulsatility and leading to hypogonadotropic hypogonadism (HH) and infertility. This review synthesizes molecular, translational, and clinical data highlighting the central role of kisspeptin-mediated signaling in leptin-dependent reproductive regulation. Current therapeutic limitations are discussed alongside emerging approaches, including kisspeptin-based therapies and receptor-targeted strategies. Elucidating how LEPRb dysfunction disrupts metabolic–reproductive integration may provide insights into both rare monogenic conditions and common obesity-associated reproductive dysfunction. Full article

Polycystic ovary syndrome (PCOS) is a heterogeneous endocrine–metabolic disorder associated with insulin resistance (IR), visceral adiposity, and increased cardiometabolic risk. The visceral adiposity index (VAI) is a validated surrogate marker of adipose tissue dysfunction, but its relationship with circulating neurotrophins and adipokine balance in PCOS remains incompletely understood. In this study, 100 women with PCOS were stratified into lower- (n = 50) and higher-risk (n = 50) groups according to VAI. Anthropometric measures, fasting glucose and insulin concentrations, lipid profile, and serum levels of brain-derived neurotrophic factor (BDNF), nerve growth factor-β (NGFβ), leptin, adiponectin, and resistin were assessed. HOMA-IR, adipokine ratios and atherogenic indices were calculated. Multivariate regression showed that BDNF was independently associated with VAI and non-HDL cholesterol, whereas NGFβ was independently linked to HDL cholesterol and estradiol, highlighting neurotrophin relationships with metabolic and endocrine parameters beyond general adiposity. Correlation heatmap and network analyses demonstrated interconnected clusters linking visceral adiposity, IR, dyslipidemia, adipokine imbalance, and neurotrophins, with the leptin/adiponectin ratio emerging as a central integrative marker. These findings suggest that within a PCOS population, VAI-defined cardiometabolic risk is associated with distinct neurotrophin–adipokine signatures, highlighting neurotrophin–adipokine networks underlying visceral adiposity-driven cardiometabolic and endocrine risk. Full article

This study investigated the effects of a high-fat diet (HFD), particulate matter (PM) exposure, and resistance exercise training on circulating lipid profiles, adipokines, inflammatory responses, neurotrophic factors, and blood–brain barrier (BBB) permeability. Forty-eight 10-week-old male C57BL/6 mice were randomly assigned to four groups (n = 12 per group): normal diet (ND), HFD, HFD with PM exposure (HFD + PM), and HFD with PM exposure plus exercise training (HFD + PM + EX). ND and HFD were administered for 16 weeks, whereas PM exposure and exercise training interventions were initiated after 8 weeks of dietary treatment and continued for an additional 8 weeks. PM was administered via tail vein injection three times per week, and resistance exercise training consisted of a ladder-climbing exercise performed five times per week. The results indicated that body weight, total cholesterol (TC), triglycerides (TGs), low-density lipoprotein cholesterol (LDL-C), leptin, interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), S100 calcium-binding protein B (S100B), and neuron-specific enolase (NSE) levels were significantly higher in the HFD group than in the ND group (p < 0.05), whereas adiponectin and brain-derived neurotrophic factor (BDNF) levels were significantly lower (p < 0.05). In addition, the HFD + PM group exhibited significantly lower BDNF and vascular endothelial growth factor (VEGF) levels (p < 0.05) and significantly higher S100B and NSE levels (p < 0.05) than the HFD group. In contrast, the HFD + PM + EX group showed significantly lower TG, LDL-C, leptin, and IL-6 levels than the HFD group (p < 0.05). Moreover, compared with the HFD + PM group, the HFD + PM + EX group demonstrated significantly lower TG, LDL-C, leptin, S100B, and NSE levels (p < 0.05) and significantly higher high-density lipoprotein cholesterol (HDL-C), adiponectin, BDNF, and VEGF levels (p < 0.05). Collectively, these findings suggest that an HFD may contribute to dyslipidemia, heightened inflammatory responses, downregulation of neurotrophic factors, and increased BBB permeability and that concurrent PM exposure under HFD conditions may exacerbate adverse alterations in neurotrophic factors and BBB permeability. The results indicate that an HFD induces metabolic and neurovascular alterations, whereas concurrent PM exposure under HFD conditions is associated with additional changes in neurotrophic factors and BBB-related markers. Resistance exercise training attenuated these changes. Full article

Objective: This double-blind, parallel-group randomized controlled trial is the first to investigate the synergistic effects of interval resistance plus progressive aerobic training with fisetin supplementation on adipokines in obesity. Methods: Sixty sedentary men with obesity (BMI < 30 kg/m²) completed 12 weeks of thrice-weekly interval resistance training (eight exercises, 3 × 13 reps at 60% 1RM with 20% 1RM active rest), immediately followed by staged aerobic bouts (50–70% HRmax). Participants were randomized into the control-placebo (P), fisetin (F; 200 mg/day), training-placebo (TP), or training + fisetin (TF) groups. The primary outcomes were asprosin, MCP-1, and adiponectin; secondary outcomes included leptin and lipid profile. Data were analyzed via ANCOVA with Bonferroni post hoc tests. Results: Statistical analyses were conducted following the intention-to-treat (ITT) principle using an analysis of covariance (ANCOVA) model, which revealed extensive effects of the interventions on the participants’ anthropometric and biochemical indices. Regarding body composition, after adjusting for baseline values, a significant difference in mean body weight was observed between groups (F (3, 55) = 9.444, p < 0.001, ηp² = 0.340); Bonferroni post hoc tests confirmed that the training plus fisetin (TF), training-placebo (TP), and fisetin (F) groups all achieved significant weight loss compared to the placebo (P) group. Furthermore, body mass index (BMI) showed a significant inter-group difference (p = 0.021), with post hoc analysis revealing that only the TF group reached a statistically significant reduction compared to the placebo (p = 0.024; 95% CI [−3.760, −0.172]). In the assessment of biochemical and inflammatory variables, the interventions exerted a highly significant effect on asprosin (F (3, 55) = 36.047, p < 0.001; ηp² = 0.663) and MCP-1 (F (3, 55) = 29.570, p < 0.001; ηp² = 0.617). The findings indicated that the TF group experienced the most substantial reductions in both asprosin (−60.71%) and MCP-1 (−46.50%) levels. Regarding adipokines, significant increases in adiponectin levels were observed in the TP (29.38%) and TF (27.67%) groups (p < 0.05), whereas changes in leptin were statistically significant only in the TF group relative to the placebo (p = 0.049). The lipid profile results indicated a statistically significant difference in the TF group in improving all markers; this group achieved greater reduction compared to other groups, including reductions in LDL-C, triglycerides (TG), and total cholesterol (TC) (p < 0.001), while simultaneously showing a significant elevation in HDL-C. Post hoc analyses confirmed robust statistical differences in all lipid parameters for both the TF and TP groups compared to the placebo group (p < 0.05), whereas the placebo group experienced a deterioration in status characterized by a significant increase in LDL-C (p = 0.027) and a significant decline in HDL-C concentrations (p = 0.006). Conclusions: In conclusion, 12 weeks of combined interval resistance–aerobic training and fisetin supplementation significantly reduced pro-inflammatory adipokines and improved lipid profiles in obese men. These findings suggest that asprosin serves as a potential modulator in metabolic risk reduction; however, since direct mechanistic assays were not conducted, these implications remain hypothetical. Future research employing molecular readouts is warranted to confirm the underlying pathways involved. Full article

The triad association among type 2 diabetes mellitus (T2DM), metabolic associated fatty liver disease (MAFLD), and incretin secretion dysfunction, including GLP-1 (glucagon-like peptide-1) secretion dysfunction, maintains a critical cardiovascular risk and liver-related mortality. The aim of this study is to establish interactions between the GLP-1 plasma levels and metabolic syndrome clusters and adipokines profile (leptin, adiponectin, resistin) and proinflammatory cytokines (TNFα, IL-6, IL1β, IL-17) in diabetic subjects with or without MAFLD. The data revealed that insulin resistance (HOMA-IR) is present in all groups. MAFLD is more common in men than in women. The average FLI score in group IV was ≥70, confirming the diagnosis of MAFLD. The disorder of GLP-1 secretion is more pronounced in women than in men. HOMA-IR is negatively associated with plasma GLP-1 depletion in the MAFLD, T2DM, and MAFLD + T2DM groups. Adiponectin levels are decreased in all groups, as for GLP-1. In contrast, leptin, resistin, TNFα, IL-6, IL-1β, and IL-17 levels show an inverse correlation with GLP-1. GLP-1 accurately reflects metabolic and inflammatory status in subjects with MAFLD, T2DM, and diabetes—steatosis. The applied multivariate linear regression model confirms a highly significant association between MAFLD and GLP-1. It appears that plasma GLP-1 can be considered as biomarker in MAFLD and T2DM related to sex-gender disparities. Longitudinal studies are required to confirm these data. Full article

Antiretroviral drugs are associated with increased body weight and metabolic disorders. Fat gain and insulin resistance are commonly associated with abdominal obesity in people with HIV (PWH). There is currently an open ongoing discussion about how antiretroviral therapy affects body weight and its significance in hunger–satiety circuit alteration. Until now, the impact of the drug on this circuit has not been explored. This study aimed to assess the hormones involved in appetite and satiety regulation in the serum and hypothalamus after efavirenz (EFV) administration in mice. EFV (10 mg/kg) and distilled water (1.5 μL/kg) (control group) were orally administered for 36 days to CD1 mice. Body weight and food intake were determined throughout treatment. At the end of the treatment, the metabolic profile (glucose, triglycerides, cholesterol) was assessed, and leptin, soluble receptor of leptin (sOB-R), and ghrelin were measured in serum; moreover, we evaluated the expression of growth hormone secretagogue receptor 1a (GHS-R1a), neuropeptide Y receptor 1 (NPYR1), and leptin in the hypothalamus, and a sucrose preference test (SPT) was conducted. Outcomes showed an increase in serum ghrelin and the expression of GHS-R1a and NPYR1 receptors in the hypothalamus, coinciding with an increase in appetite and preference for sucrose in mice in the EFV group. Furthermore, serum leptin, sOB-R, and the free leptin index (FLI) showed that hunger is not related to a lack of satiety. Despite increased food intake, a reduction in body weight was observed, and triglyceride and cholesterol levels were increased. According to our findings, mice treated with EFV showed a decrease in body weight, despite increased food intake resulting from appetite stimulation, which is caused by specific compounds, hormones, and neural signals acting on the brain’s hunger centres, primarily in the hypothalamus, promoting eating behaviours. However, further studies are necessary to investigate the mechanisms of EFV’s effects on energy expenditure. Full article

Background/Objectives: Both HIV infection and antiretroviral therapy contribute to dyslipidemia and abnormal body fat distribution in people living with HIV (PLWH). Exercise training is an effective intervention to protect against these metabolic changes. However, little is known about the mechanisms underlying the impact of exercise training on lipid metabolism in PLWH. This study aimed to comparatively evaluate the effect of high-intensity functional circuit training on the plasma lipidome of PLWH and HIV-negative subjects (control). Methods: PLWH (n = 13) and control (n = 14) were submitted to 8 weeks of exercise training. Body composition, anthropometric, and biochemical parameters were measured. Plasma was obtained in a fasting state for lipidomic analysis. Results: Anthropometric and biochemical parameters revealed lower levels of leptin, HDL-C, body fat %, and BMI combined with elevated aspartate transaminase (AST) and Homeostasis Model Assessment of β-cell function (HOMA_beta) in PLWH when compared to control subjects that persisted from baseline to post-exercise training. Nonetheless, contrasting levels of adiponectin, fasting insulin, and phosphatidylcholine-containing lipids observed at baseline were equalized after training in PLWH. In control subjects, significant reductions in concentrations of triglycerides alongside phosphatidylinositol and glycosylated ceramides were observed post-exercise training. By contrast, PWLH displayed an increase in diglycerides, acylcarnitines, and free cholesterol levels after exercise training, together with decreased concentrations of free fatty acids, cholesteryl esters, and glycosylated ceramides. Conclusions: In addition to specific lipidome alterations in each group, particularly driven by improved insulin resistance in PLWH, this study showed concomitant modulation of several glycerophospholipids and sphingolipids, suggesting health-promoting effects of short-term exercise training. Collectively, these modulated lipid species represent interesting targets for future lipidomic-based studies evaluating not only the effects of exercise training but also the molecular mechanisms resulting in a healthier plasma lipidome profile. Full article

The neuroendocrine and immune systems interact bidirectionally through shared ligands and receptors during inflammation, thereby regulating immune responses. Leptin, primarily known for its role in energy metabolism and appetite regulation, also modulates neuroinflammatory pathways. Its receptors are widely expressed on immune cells and contribute to immune mechanisms implicated in the pathogenesis of neuroinflammatory disorders such as multiple sclerosis (MS) and Alzheimer’s disease (AD). This review highlights recent advances in understanding leptin’s role in immune regulation, with a focus on its impact on MS and AD. A comprehensive literature review was conducted until October 2025, using PubMed, Google Scholar, and Scopus to identify studies investigating leptin in neuroinflammatory conditions, particularly MS and AD. Leptin exerts broad immunomodulatory effects by activating T cells, dendritic cells, and microglia, and promoting their proliferation and phagocytosis. Its elevation enhances Th1 and Th17 responses, drives pro-inflammatory macrophage phenotype polarization, and suppresses regulatory T cell and Th2 responses, immune pathways involved in MS. Peripheral leptin levels are increased in MS, especially during disease exacerbations. In contrast, in AD, they are typically reduced, particularly in patients with normal body mass index (BMI), where their decline contributes to amyloid-β and tau pathology. These divergent patterns position leptin as a bidirectional regulator at the intersection of immunity and neurodegeneration. Additionally, its protective or detrimental effects likely depend on whether it acts under physiological conditions or in the context of obesity-induced leptin resistance. Elevated leptin levels in obesity exacerbate inflammation and diminish its neuroprotective effects. In conclusion, leptin is elevated in MS patients but downregulated in AD, reflecting its bidirectional effects. In leptin resistance, peripheral proinflammatory signaling is maintained while central leptin signaling is restricted, thereby potentially promoting autoimmunity in MS and limiting neuroprotection in AD. Further mechanistic and longitudinal studies are needed to clarify the relationship between leptin dysregulation, leptin resistance, neuroinflammatory and neurodegenerative diseases. Full article

Major depressive disorder is increasingly recognized as a metabolic–immune disorder in which chronic inflammation diverts tryptophan (Trp) metabolism toward the kynurenine pathway (KP), reducing serotonin synthesis and producing neurotoxic metabolites such as quinolinic acid (QA). Elevated kynurenine (KYN)/Trp ratios and an altered QA/kynurenic acid (KYNA) balance have been consistently reported in depressed individuals, implicating the KP as a key therapeutic target. Exercise provides a unique, translationally relevant intervention: unlike pharmacological agents acting directly on neurotransmission, contracting skeletal muscle acts as a “kynurenine sink” by inducing kynurenine aminotransferases that convert circulating KYN into neuroprotective KYNA, thereby reducing brain KYN uptake and mitigating excitotoxicity. Clinical studies and meta-analyses confirm that aerobic, resistance, and high-intensity training produce antidepressant effects comparable to pharmacotherapy, while also improving cognition, fatigue tolerance, and cardiometabolic function. Beyond KP remodeling, exercise-induced myokines (irisin, IL-6, BDNF, apelin, FGF21) and adipokines (adiponectin, leptin modulators) coordinate systemic anti-inflammatory and neurotrophic adaptations that enhance resilience and brain plasticity. Furthermore, pharmacological “exercise mimetics” and metabolic modulators, such as PPAR agonists, AMPK activators, NAD⁺ boosters, meldonium, trimetazidine, and adiponectin receptor agonists, may be promising adjuncts for patients with low exercise capacity or metabolic comorbidities. This review provides a novel concept, positioning exercise as a systemic antidepressant that breaks the kynurenine lock of depression. Through proper interpretation of skeletal muscle as an endocrine organ of resilience, we integrate molecular, clinical, and translational findings to show how exercise remodels Trp–KYN metabolism and inflammatory signaling and how pharmacological mimetics may extend these benefits. This perspective consolidates scattered mechanistic and clinical data and outlines a forward-looking therapeutic framework that links exercise and lifestyle, metabolism, and drug discovery. We highlight that re-consideration of our understanding of depression, as a whole-body disorder, should provide new opportunities for precision interventions. Full article