Positional cloning of the mouse obese gene and its human homologue

One-year metreleptin in Colombian sisters with congenital leptin deficiency

We discovered two adult sisters in Colombia, lineally consanguineous, with severe obesity and undetectable serum leptin levels despite markedly elevated body fat. Their clinical profile included childhood-onset extreme weight gain, intense hunger, hyperphagia, hypogonadotropic hypogonadism, and family history of obesity. Direct sequencing of the LEP gene revealed a novel homozygous missense mutation in exon 3 (c.350G>T [p.C117F]). The presence of this mutation, undetectable leptin, and severe obesity confirmed a diagnosis of monogenic leptin deficiency. Here we describe the clinical outcomes of a 12-month treatment with recombinant human leptin (metreleptin). Metabolic and endocrine assessments were conducted before and after therapy. Metreleptin therapy significantly reduced BMI: from 59 to 38 kg/m2 (OBX1, age 27) and 60 to 48 kg/m2 (OBX2, age 24). Total body fat mass decreased, serum lipids normalized, and insulin sensitivity improved. Hypogonadotropic hypogonadism reversed, and menstruation resumed. Thus, metreleptin reversed the major metabolic and endocrine abnormalities associated with leptin deficiency in these sisters. Limitations include the small sample size, absence of a control group, and lack of anti-metreleptin antibody measurements. Nevertheless, our findings support that leptin replacement with metreleptin is currently the only effective hormonal treatment for this monogenic form of human obesity.

Expression of leptin and its long-form receptor in the porcine corpus luteum during pregnancy and the protective role of leptin in corpus luteum function invitro

Although the hormone leptin and its long-form receptor (LEPR) have been identified in the porcine ovary, their direct roles in mediating corpus luteum (CL) function in pregnant sows have not been clearly defined. In this study, we investigated leptin and LEPR expression in the porcine CL during pregnancy and evaluated the effect of the hormone on CL function in vitro. Leptin and LEPR were continuously expressed in the CL throughout pregnancy, and their expression patterns were generally similar, with higher levels in the early and middle stages of pregnancy and lower levels in the late stage. Immunohistochemical analysis revealed that both leptin and LEPR were predominantly localized in the luteal cells, with strong immunostaining observed in the early and middle stages CL and weak immunostaining in the late stage. Leptin 1-100 nM concentrations significantly increased the viability of cultured luteal cells (P < 0.05) and promoted their release of progesterone (P4) in a dose-dependent manner. Furthermore, leptin attenuated the prostaglandin F2α (PGF2α)-induced decreases in cell viability and P4 release. Additionally, leptin was found to have stimulatory effects on luteinizing hormone (LH) and prostaglandin E2 (PGE2) release but an inhibitory effect on PGF2α secretion. In conclusion, the presence of leptin and LEPR in the CL and the stimulatory effects of the hormone on the viability of luteal cells and their release of P4, LH, and PGE2 suggest that leptin has a positive regulatory effect on CL function in pregnant sows.

Evaluation of leptin, insulin, orexin, neuropeptide y (NPY) levels in postmortem CSF samples in suicide deaths

BACKGROUND

Suicide remains a significant global public health issue. According to the World Health Organization (WHO), suicide was the third leading cause of mortality among individuals aged 15-29 in 2021, with a total of approximately 726,000 cases reported annually. The etiology of suicide is complex, involving a combination of biological, genetic, and environmental factors, as well as family history, gender, age, personality traits, cultural background, geographic location, medical conditions, mental illnesses, addictions, and psychosocial stressors. Dysregulation of the Hypothalamic Pituitary Adrenal (HPA) axis and the effects of chronic stress play significant roles in the pathophysiology of mood disorders and suicidal behavior.

OBJECTIVE

This study aimed to investigate the levels of Neuropeptide Y (NPY), Orexin, Leptin, and Insulin in cerebrospinal fluid (CSF) samples of individuals who died by suicide compared to those who died from non-suicidal causes.

METHOD

The study examined 35 cases of suicide by hanging and 35 cases of non-suicidal deaths unrelated to head trauma. Levels of NPY, Orexin, Leptin, and Insulin in CSF samples collected during toxicological examinations were compared between suicide and control groups.

RESULTS

NPY levels were significantly higher in the suicide group than in the control group (p < 0.001). No statistically significant differences were found in Orexin (p = 0.194), Insulin (p = 0.892), or Leptin (p = 0.445) levels between the groups.

CONCLUSIONS

While no definitive biomarkers for diagnosing or predicting suicidal behavior exist, this panel of biomarkers could provide valuable insights for developing targeted treatments to manage patients at risk.

Synergistic effects of a body shape index and depression on mortality in individuals with low sexual frequency

BACKGROUND

Individuals with low sexual frequency often experience comorbidities that exacerbate mortality. This article evaluates the predictive value of five body fat anthropometric indicators for all-cause mortality and explores the interaction between obesity and depression in mortality among young and middle-aged individuals with sexual frequency <12 times per year.

METHODS

This study included participants with a sexual frequency of <12 times per year from the 2015-2016 National Health and Nutrition Examination Survey (NHANES). We assessed the impact of anthropometric indicators and depression on mortality, as well as their synergistic interactions, and further developed an accessible predictive survival model.

RESULTS

A total of 4978 participants aged 20-59 were included, with 215 deaths (4.3 %) over 15 years of follow-up. A Body Shape Index (ABSI) showed the strongest association with all-cause mortality, with an AUC of 0.67. Participants with ABSI ≥0.082 had a significantly higher risk of death (HR: 1.87, 95%CI: 1.31-2.68), as did those with depression (HR: 1.86, 95%CI: 1.19-2.92). Interaction analysis revealed a synergistic effect between depression and ABSI, increasing death risk by 293 % when both were present. Significant survival differences were observed between men and women with these risk factors, with median survival rates of 76.3 % and 90.8 %, respectively. The model based on ABSI and depression provided valuable mortality predictions, with AUC of 0.78, 0.77, and 0.77 for 3-year, 5-year, and 10-year survival.

CONCLUSION

ABSI and depression are associated with all-cause mortality in individuals with low sexual frequency, potentially creating a synergistic effect on mortality risk.

Association of childhood emotional neglect, circulating protein biomarkers, with gastrointestinal disorders among UK biobank participants

OBJECTIVE

To explore the association between CEN and GIDs, and elucidated the potential role of circulating protein biomarkers.

PATIENTS AND METHODS

The study utilized UK Biobank data from 156,686 participants, with data collection occurring between March 13, 2006 and October 1, 2010. Participants with GIDs at baseline were excluded from further analysis. CEN data were obtained from the baseline assessments. Differential protein analyses were conducted using OLINK data. GIDs and their subclasses were identified through electronic health records. Cox proportional hazards regression models were employed to assess the association between CEN and the risk of GIDs, along with sensitivity and multidimensional stratification analyses. Additionally, mediation analysis was performed to explore the role of differential protein biomarkers.

RESULTS

The results indicated that the mild CEN (CENmild) group was associated with a significantly lower risk of various GIDs than the severe CEN (CENsevere) group, including overall GIDs (HR = 0.78,95%CI:0.74-0.81) and peptic ulcers (HR = 0.37,95%CI:0.20-0.68). OLINK differential analysis revealed that APOF expression was significantly higher in the CENmild group compared to the CENsevere group (PAPOF = 7.09E-08,FC = 0.048), whereas other differential protein expression (PBPIFB2 = 8.93E-06,FC = -0.122;PFABP4 = 3.19E-06,FC = -0.101;PGGH = 4.58E-07,FC = -0.054;PLEP = 5.39E-08,FC = -0.195) was significantly lower in the CENsevere group. Cox regression analysis showed that higher APOF expression was associated with a reduced risk of multiple GIDs, while the expression of other differential proteins increased the risk of corresponding GIDs. Mediation analysis indicated that these proteins mediated 0.5 % to 6.7 % of the CEN-GIDs association.

CONCLUSION

In this cohort study, CEN was significantly associated with a higher risk of GIDs in the adulthood, and circulating protein biomarkers partially mediated the associations.

Changes in plasma UCP-1, leptin, lipids, and pro-inflammatory interleukins in calves from birth to weaning

The neonatal period is crucial for calf development, particularly for immune acquisition through colostrum intake, this study aimed to assess the energy metabolism and inflammatory response. Ten Italian Simmental calves were monitored from birth to 60 days of age, with blood samples taken at birth (0 d) to weaning. Plasma concentrations of UCP-1, leptin, TNF-α, IL-1β, IL-6, lipids, triglycerides, and total cholesterol were measured. Results showed significant dynamic changes (P < 0.05) in all parameters and showing an increasing trend from birth to the 60 d of age in investigated calves. The plasma leptin levels were positively correlated with the concentration of UCP-1 (r = 0.37, P = 0.0003), total lipids (r = 0.47, P < 0.0001), triglycerides (r = 0.53, P < 0.0001), total cholesterol (r = 0.38, P = 0.0002), and negatively correlated with TNF-α (r = -0.24, P 0.02). UCP-1 was positively correlated with the levels of total lipids (r = 0.31, P = 0.003), triglycerides (r = 0.29, P = 0.005), and IL-1β (r = 0.29, P = 0.005) in calves throughout the monitoring period. IL-6 values positively correlated with total lipids (r = 0.36; P = 0.0004), triglycerides (r = 0.37; P = 0.0003), and total cholesterol (r = 0.21; P = 0.04) in calves throughout the monitoring period. These findings suggest that lipid metabolism and inflammatory responses undergo significant changes as calves adapt to the neonatal phase and transition to solid food, with nutritional shifts playing a key role in metabolic and immune system development.

Considerations in the treatment of individuals with obesity and periodontitis

Two common non-communicable diseases, obesity and periodontitis, are responsible for and affected by systemic inflammation, sharing common risk factors and mechanistic pathways. Periodontitis is an irreversible immune-mediated inflammatory disease of hard and soft tissue supporting teeth. If left untreated, periodontitis can lead to tooth loss, affecting food choices and healthy eating, therefore affecting overall health. Obesity is an independent predictive factor for worsened periodontal inflammation, increased onset, progression, severity, and recurrence of infection, as well as delayed wound healing. Thus, managing obesity and associated metabolic dysfunctions may improve periodontal therapy outcomes. The chronic inflammatory state of obesity impairs immune regulation exacerbating the inflammatory gingival tissue destruction of periodontitis, which can also systemically contribute to inflammatory mediators. Furthermore, bariatric surgeons and dietitians should educate patients with obesity regarding the risk of elevated caries, xerostomia, and periodontitis risk from acid reflux and frequent food intake. Non-dental healthcare professionals should recognise periodontal disease signs to prompt dental referral when warranted. Asking patients about recent dental visits promotes patient involvement in cross-discipline dialogue to enhance patient care coordination between medicine and dentistry. This article discusses the association between these two diseases, the challenges of achieving optimal periodontal treatment outcomes, and the clinical strategies to enhance holistic care. It also explores oral health considerations in dietary and surgical interventions in the treatment of obesity.

Kidney consequences of obesity

Herein, we review the devastating consequences of the worldwide obesity epidemic on kidney health and outcomes. We submit that the obesity epidemic is the most pressing public health crisis facing the nephrology community today. A historical approach has been undertaken, wherein major breakthroughs in the recognition and understanding of obesity-related kidney disease (ORKD) are highlighted. We begin with a description of the worldwide obesity epidemic followed by an account of the discovery and characterization of ORKD. A detailed summary of the pathophysiology of ORKD disease is presented, wherein we set forth the following two propositions: first, ORKD is due to a maladaptive response to caloric surplus; and second, this maladaptive response causes kidney damage via hemodynamic (hyperfiltration), hormonal (adipokine dysregulation), and lipotoxic pathways. Each of these pathways is described, with particular emphasis on the relatively recent discovery that the final stage of cellular injury in ORKD is mitochondrial oxidative damage. The prevention and treatment of ORKD are then discussed, including environmental, behavioral, pharmacologic, and surgical options. Finally, we conclude with suggestions for future research to improve early recognition and treatment of ORKD.

Effects of ammonia exposure on the expression of IL-1β, CRH, and lep-a1 genes in common carp (Cyprinus carpio)

BACKGROUND

Common carp is one of the most economically important freshwater fish species globally. Ammonia exposure, a frequent challenge in aquaculture, can lead to significant economic losses. This study investigated the impact of un-ionized ammonia (UIA) exposure on the expression profiles of three key genes in common carp fry: interleukin-1 beta (IL-1β), corticotropin-releasing hormone (CRH), and leptin a1 (Lep-a1). These genes are crucial indicators of immune response, stress regulation, and appetite control, respectively. Fish were exposed to 0.7 mg/L of UIA, and gene expression was analysed in liver and gill tissues at five time points (12 h, 2-, 4-, 7-, and 14-days of exposure) using quantitative real-time PCR (RT-qPCR).

RESULTS

Results demonstrated that expression levels of all three genes were significantly affected by exposure time and tissue type. IL-1β, CRH, and Lep-a1 were upregulated in both liver and gill tissues, with the liver consistently showing higher expression levels. Notably, significant positive correlations were observed between each pair of the three genes studied, suggesting a coordinated physiological response to ammonia stress. The liver emerged as a key organ in orchestrating the long-term adaptive response, while the gills exhibited a more acute, transient reaction.

CONCLUSIONS

This study provides valuable insights into the molecular mechanisms underlying the physiological response of common carp to ammonia toxicity. The findings highlight the complex interplay between immune, stress, and metabolic pathways in coping with ammonia exposure. A deep understanding of these mechanisms could lead to improved management strategies in aquaculture and the development of potential biomarkers for assessing stress responses in fish populations.

Modulating the Secretome of Fat to Treat Heart Failure

Heart failure afflicts >6 million individuals in the United States alone and is associated with significant mortality (≈40% within 5 years of diagnosis) and cost (estimated to exceed $70 billion in the United States by 2030). Obesity is a major risk factor for the development of heart failure. The contribution of excess adipose tissue to heart failure pathogenesis is multifactorial. For example, adipose tissue-driven inflammation contributes to the development of other cardiometabolic comorbidities, such as hypertension, leading to left ventricular pressure overload and adverse remodeling of the heart. Adipose tissue also functions as an endocrine organ, and altered secretion of proteins, lipid mediators, metabolites, and small extracellular vesicles (collectively referred to as the secretome) from dysfunctional fat can lead to cardiac inflammation and oxidative stress, which drive changes in structure and function of the heart. In this review, we begin with an overview of current therapies for obesity and what is known about how they influence the heart. Then we focus on mechanisms by which fat communicates with the heart via secreted factors and highlight druggable nodes in this circuit that could be exploited to develop next-generation therapies for heart failure.

Relationship Between Leptin and Heart Failure: A Meta-Analysis

Background

Heart failure (HF) is a diverse and potentially fatal condition affecting more than 60 million people worldwide. Previous studies have identified a close relationship between leptin levels and HF, and that leptin levels in patients with HF are higher than those in healthy individuals. However, some studies have reported inconsistent results. Therefore, the association between leptin levels and HF remains controversial.

Methods

A literature search was conducted on the Web of Science, Wiley Online Library, Embase, and PubMed databases. The title or abstract search term 'leptin' was used in combination with 'heart failure' and 'HF'. Meta-analysis results were reported as standardized mean differences (SMD) with corresponding 95% confidence intervals (CI).

Results

Eighteen studies comprising 1149 patients with HF and 622 healthy controls were included in the meta-analysis. Leptin levels in patients with HF were significantly higher than those in healthy individuals (SMD, 0.54; 95% CI [0.15, 0.93]).

Conclusions

To our knowledge, this systematic review is the first to evaluate the relationship between leptin and HF. Determining the role of leptin in HF will significantly contribute to its diagnosis and treatment.

Neural Mechanisms in Cardiovascular Health and Disease

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

Characterizing differences in the muscle transcriptome between cattle with alternative LCORL-NCAPG haplotypes

BACKGROUND

The LCORL-NCAPG locus is a major quantitative trait locus (QTL) on bovine chromosome 6 (BTA6) that influences growth and carcass composition in cattle. To further understand the molecular mechanism responsible for the phenotypic changes associated with this locus, twenty-four Charolais-sired calves were selected for muscle transcriptome analysis based on alternative homozygous LCORL-NCAPG haplotypes (i.e., 12 "QQ" and 12 "qq", where "Q" is a haplotype harboring variation associated with increased growth). At 300 days of age, a biopsy of the longissimus dorsi muscle was collected from each animal for RNA sequencing.

RESULTS

Gene expression analysis identified 733 genes as differentially expressed between QQ and qq animals (q-value < 0.05). Notably, LCORL and genes known to be important regulators of growth such as IGF2 were upregulated in QQ individuals, while genes associated with adiposity such as FASN and LEP were downregulated, reflecting the increase in lean growth associated with this locus. Gene set enrichment analysis demonstrated QQ individuals had downregulation of pathways associated with adipogenesis, alongside upregulation of transcripts for cellular machinery essential for protein synthesis and energy metabolism, particularly ribosomal and mitochondrial components.

CONCLUSIONS

The differences in the muscle transcriptome between QQ and qq animals imply that muscle hypertrophy may be metabolically favored over accumulation of fat in animals with the QQ haplotype. Our findings also suggest this haplotype could be linked to a difference in LCORL expression that potentially influences the downstream transcriptional effects observed, though further research will be needed to confirm the molecular mechanisms underlying the associated changes in phenotype.

Long-Acting Human PASylated Leptin Reaches the Murine Central Nervous System and Offers Potential for Optimized Replacement Therapy

Despite the multifaceted role of leptin for energy homeostasis and its broad therapeutic potential, the FDA/EMA-approved metreleptin constitutes the only leptin drug to date. To translate the promising results from previous studies on murine PASylated leptin with improved solubility and extended plasma half-life using PASylation technology─a biological alternative to PEGylation─we have developed a second-generation human leptin drug candidate and tested it rigorously in vitro and in vivo. To this end, the exposed hydrophobic Trp residue at position 100 in human leptin was replaced by Gln, which, together with the genetic fusion with a 600-residue PAS polypeptide, yielded a protein with high solubility, folding stability and receptor-stimulatory activity. In a pharmacokinetic (PK) study with wild-type mice, this modified human leptin showed an extended plasma half-life of 18.8 ± 3.6 h after subcutaneous (s.c.) injection. Furthermore, leptin-deficient mice were dosed s.c. with the modified human leptin carrying two different PAS fusion tags, PAS#1 or P/A#1, each comprising 600 residues. After only four doses, the disease phenotype, including morbid adiposity, hyperphagia, and hepatic steatosis, was completely reversed by both PASylated leptin versions, but not by the non-PASylated leptin if administered at the same dose. To assess its tissue distribution, P/A(200)-huLeptinW100Q was doubly labeled with two fluorescent dyes, which were specifically attached to the leptin and the PAS moiety, respectively. Analysis of relevant mouse organs by light sheet fluorescence microscopy after clearance revealed colocalized signals in the kidney and liver, thus indicating general stability of the PAS-leptin fusion protein in vivo. However, discrete signals were observed in the hypothalamic region, only with leptin detectable in the choroid plexus, which implies cleavage of the PAS tag during transcytosis across the physiological barriers. This study should pave the way toward a second-generation leptin drug enabling prolonged dosing intervals.

Drosophila as a Genetic Model System to Study Organismal Energy Metabolism

Metabolism is the essential process by which an organism converts nutrients into energy to fuel growth, development, and repair. Metabolism at the level of a multicellular, multi-organ animal is inherently more complex than metabolism at the single-cell level. Indeed, each organ also must maintain its own homeostasis to function. At all three scales, homeostasis is a defining feature: as energy sources and energetic demands wax and wane, the system must be robust. While disruption of organismal energy homeostasis can be manifested in different ways in humans, obesity (defined as excess body fat) is an increasingly common outcome of metabolic imbalance. Here we will discuss the genetic basis of metabolic dysfunction that underlies obesity. We focus on what we are learning from Drosophila melanogaster as a model organism to explore and dissect genetic causes of metabolic dysfunction in the context of a whole organism.

Leptin Levels in Acute and Recovered Eating Disorders: An Arm-Based Network Meta-Analysis

OBJECTIVE

This study aimed to provide a BMI-adjusted meta-analytical calculation of blood leptin levels across different eating disorders (EDs) including anorexia nervosa (AN), bulimia nervosa (BN), binge eating disorder (BED), recovered EDs, and healthy controls (HCs). The goal was to understand BMI-independent leptin alterations and their potential as biomarkers.

METHOD

PubMed and ClinicalTrials.gov were searched for studies reporting serum leptin in AN, BN, BED, or recovered EDs. A multilevel network meta-analysis using a linear mixed-effects meta-regression model, adjusting for BMI, sex, and assay type, was performed on 146 studies (5048 patients, 3525 controls).

RESULTS

Significant differences in leptin levels were found across EDs. AN patients exhibited the lowest leptin levels, while BED patients had the highest. BN and recovered AN patients had leptin levels similar to AN, significantly lower than HCs. BMI, sex, and assay type were significant covariates. The model accounted for heterogeneity due to diagnostic criteria, assay types, and study-level differences.

CONCLUSIONS

Leptin levels in EDs are significantly altered beyond BMI effects, suggesting disease-specific factors. These findings support leptin's potential as a biomarker for ED staging and prognosis. Further research is needed to explore leptin's role in ED pathogenesis and trajectory, to identify subpopulations and improve clinical interventions.

Human adaptation response to obesity

This article examines the human body's adaptive responses to obesity from biological, behavioral, and evolutionary perspectives. It explores how ancient survival mechanisms, such as fat storage during scarcity, have persisted but become maladaptive in modern contexts of food abundance and sedentary lifestyles. Using the Thrifty Gene Hypothesis and General Adaptation Syndrome (GAS), the study investigates how chronic stress and genetic predispositions contribute to obesity. Chronic stress, as described in GAS, is linked to obesity through mechanisms like prolonged cortisol elevation, which promotes fat storage, particularly in the abdominal region, and disrupts hunger and satiety regulation. The article also explores the possibility that contemporary chronic stress may cause the body to buffer stressful conditions through fat accumulation. While the Thrifty Gene Hypothesis suggests that genetic traits evolved to optimize energy storage during scarcity, contributing to obesity in modern environments, it remains controversial. Critics argue that it oversimplifies obesity's causes, such as lifestyle and environmental factors. Although genetic variations influencing obesity susceptibility continue to evolve, the physiological mechanisms of fat storage and stress adaptation have remained largely unchanged since ancient times.

Longitudinal pattern of growth performance and feeding behaviour in pigs fed varying dietary crude protein levels and categorised by final feed efficiency

Feed efficiency (FE) estimated on pen level does not take individual feed intake or feeding behaviour into account, and thus, varying response among pen mates is impossible to quantify. This study aimed to explore the within-pen variation in FE of pigs fed one of three levels of CP. The study included 60 gilts (30-115 kg) divided into two repetitions (10 pigs/pen with an automatic feeder). Pigs were fed a low (LCP; 120 g SID CP/kg), standard (SCP; 124 g SID CP/kg) or high (HCP; 128 g SID CP/kg) CP diet. Pigs within diet were categorised based on their FCR in the final four growing weeks as the 30% highest (HF), medium 40% (MF), and the 30% lowest (LF). Weekly BW, average daily gain (ADG), feed conversion ratio (FCR), and daily and per-meal feed intake and feeding behaviour were measured per individual. Data were analysed as polynomial mixed models. Growth performance parameters except FCR had significant dietary treatment (DT) × time (T) and feed conversion category × time interactions. During weeks (W) 10-12, BW tended (P ≤ 0.10) to be greater in HCP compared with LCP aligning with the numerically highest intake for HCP in the preceding period. Similarly, HF intermittently had greater BW and preceding higher intake than LF or MF (0.05 ≤ P ≤ 0.10). The ADG of LCP pigs showed the greatest variability over time and intermittently increased faster and slower (0.05 ≤ P ≤ 0.10) than SCP and HCP, respectively. From W10 onwards, the HF pigs had a stable ADG while the ADG of LF and MF increased steeply and consequently was greater (P ≤ 0.05) at W13-14. In line with ADG, FCR varied significantly over time and most strongly for LCP. Overall, LF pigs had the lowest, while HF pigs had the highest FCR (P < 0.001). Meal size (P < 0.001) and duration (P < 0.001) had a significant DT × T interaction, being greater for HCP than LCP and occasionally SCP. In line with differences in growth rate, meal frequency decreased faster (P < 0.05) for HCP than LCP or SCP, resulting in longer intervals and limited differences in daily feeding duration. While meal size and duration tended (P ≤ 0.10) to be greater for HF than MF or LF pigs, differences in daily feeding behaviour were negligible. It was concluded that, independent of CP-level, a distinction in FCR categories could be attributed to differential meal feeding behaviour of HF pigs leading to higher feed intake, whereas differences in ADG changed during the growing-finishing phase.

The Influence of the Sympathetic Nervous System on Cardiometabolic Health in Response to Weight Gain or Weight Loss

Alterations in sympathetic nervous activity are evident in response to changes in body weight. Sympathetic nervous activity and sympathetic responses to weight change are regionalized, with alterations in end organ function dependent on the changes occurring in the brain regulatory pathways invoked and in the effector organs engaged. The obesity-induced activation of the sympathetic nervous system likely contributes to the initiation and worsening of cardiometabolic risk factors, including elevated blood pressure, cardiac dysfunction, dyslipidaemia, increased fasting blood glucose, insulin resistance, and non-alcoholic steatohepatitis. Unintended weight loss, as occurs in cachexia, is driven, at least in part, by the activation of sympathetic nervous-stimulated thermogenesis. The complexity of sympathetic nervous regulation renders the use of global measures of sympathetic activity problematic and the development of targeted therapies difficult, but these are not without promise or precedent. Knowledge of the central and peripheral pathways involved in sympathetic nervous regulation has opened up opportunities for pharmacological, surgical, and device-based approaches to mitigating the burden of disease development and progression. In this narrative review, we elaborate on sympathetic activity in response to changes in body weight, the brain pathways involved, and the cardiovascular and metabolic risks associated with perturbations in regional sympathetic activity.

Transcriptomic analysis of adipose tissue reveals adipogenesis is modulated by the degree of weight loss in patients with obesity

BACKGROUND AND AIMS

Obesity is a complex condition with a diverse presentation and highly variable response to treatment. It is increasingly evident that obesity requires a plethora of interventions informed by biomarkers to optimise the chance of success. Adipose tissue is a metabolically active endocrine tissue and its metabolic response to intervention has the potential to provide key information to design targeted treatments to tackle obesity. To this aim, this study sought to identify, through transcriptomics analysis, common elements between adipose tissue of those undergoing bariatric surgery to those who were successful in losing weight through a lifestyle intervention.

METHODS AND RESULTS

Transcriptomic data from Gene Expression Omnibus were extracted from three bariatric surgery interventions and three lifestyle interventions. Paired linear mixed modelling using the limma package in R was used to determine differentially expressed genes before and after the interventions. Unpaired linear mixed modelling was used to determine differentially expressed genes between high and low responders to the intervention. Differentially modulated pathways were analysed with PathVisio and downloaded for graphic representation from the WikiPathways database.

CONCLUSION

We demonstrated that successful lifestyle interventions and bariatric surgery share the modulation of the Adipogenesis pathway (WP236). Leptin expression was positively correlated with weight loss, only up to a 10 % weight loss, suggesting a possible involvement of its dysregulation in explaining individual propensity to weight regain and potentially indicating who requires a targeted intervention. We also identify an interesting relationship between RBL2 expression and weight loss that requires further investigation.

Hypothalamic PNOC/NPY neurons constitute mediators of leptin-controlled energy homeostasis

Leptin acts in the brain to suppress appetite, yet the responsible neurocircuitries underlying leptin's anorectic effect are incompletely defined. Prepronociceptin (PNOC)-expressing neurons mediate diet-induced hyperphagia and weight gain in mice. Here, we show that leptin regulates appetite and body weight via PNOC neurons, and that loss of leptin receptor (Lepr) expression in PNOC-expressing neurons in the arcuate nucleus of the hypothalamus (ARC) causes hyperphagia and obesity. Restoring Lepr expression in PNOC neurons on a Lepr-null obese background substantially reduces body weight. Lepr inactivation in PNOC neurons increases neuropeptide Y (Npy) expression in a subset of hypothalamic PNOC neurons that do not express agouti-related peptide (Agrp). Selective chemogenetic activation of PNOC/NPY neurons promotes feeding to the same extent as activating all PNOCARC neurons, and overexpression of Npy in PNOCARC neurons promotes hyperphagia and obesity. Thus, we introduce PNOC/NPYARC neurons as an additional critical mediator of leptin action and as a promising target for obesity therapeutics.

Puberty regulation in chub mackerel Scomber japonicus, an important aquaculture fish species, via reproductive endocrine mechanism

The vertebrate reproductive system is controlled by the brain-pituitary-gonadal reproductive endocrine axis (BPG axis). Gonadotropin-releasing hormone (GnRH) secreted from the hypothalamus regulates the secretion of two gonadotropic hormones (GTHs), follicle-stimulating hormone (FSH) and luteinizing hormone (LH), in the pituitary gland. Steroid hormones, such as androgens and estrogens, secreted in response to GTH stimulation, regulate the development of male and female gametes. Recently, various neuropeptides have been identified in mammals as factors that regulate the BPG axis from the upstream, demonstrating their importance. The author's main research theme is "Understanding the mechanism underlying puberty control in aquaculturally important species." They have been actively investigating the regulatory mechanism of the BPG axis in the puberty of chub mackerel Scomber japonicus, an important fishery species. With this species, researchers can systematically collect target organs, cells, and other organs from individuals at each developmental stage, from fertilized eggs to adult fish after spawning. A highly reproducible rearing experimental system has been established, enabling verification of the knowledge gained through feedback to reared individuals. Furthermore, it has recently become possible to quickly and efficiently produce gene knockout lines using genome editing. This article introduces the mechanism of puberty control in chub mackerel by fully leveraging this experimental platform. Focus will be directed to the functions of kisspeptin, which triggers puberty by regulating GnRH secretion in mammals, and leptin, which transmits nutritional information to the reproductive axis.

Novel evidence of arsenic-related excess adiposity and its implication in the risk of cardiometabolic diseases

Arsenic exposure is associated with obesity- or excess adiposity-related disorders, including cardiometabolic diseases. Previously, many human studies attempted to establish the association of arsenic exposure with obesity, mainly through body mass index (BMI) but failed to provide any concrete evidence. Our study aimed to investigate the arsenic-related adiposity and its relationship with cardiometabolic diseases. Of the 524 participants, 126 and 398, respectively, were chosen from low- and high-arsenic exposure areas in Bangladesh. Obesity or body fat (adiposity) of the participants was measured by anthropometric measures [BMI, waist circumference (WC), and triceps skinfold thickness (TSFT)] and a serum biomarker, leptin. Sarcopenic characteristics were assessed by lean body mass (LBM) and serum creatinine levels. Insulin resistance, as measured by Homeostatic Model Assessment for Insulin Resistance (HOMA-IR), hypertension, and hyperglycemia, were considered as the risk factors for cardiometabolic diseases. There were significant positive associations between drinking water, hair, and nail arsenic concentrations and the levels of WC and TSFT after adjusting for potential confounders. However, there were no significant associations with BMI. Increased arsenic exposure levels were associated with increased leptin levels [(Regression coefficient (β) = 1.00, 95% confidence interval (CI): 0.53, 1.46) for water, (β = 1.44, 95% CI: 0.42, 2.46) for hair, and (β = 1.47, 95% CI: 0.32, 2.61) for nail arsenic]. Notably, leptin levels had inverse associations with LBM (β = -7.87, 95% CI: -13.30, -2.45) and creatinine levels (β = -15.65, 95% CI: -21.50, -9.81). Furthermore, the elevated leptin levels associated with arsenic exposure were connected to higher HOMA-IR levels (β = 0.19, 95% CI: 0.14, 0.24), higher odds of hypertension [Odds ratio (OR) = 1.31, 95% CI: 1.12, 1.53], and hyperglycemia (OR = 1.30, 95% CI: 1.13, 1.47). Taken together, the results of this study demonstrated a unique association between arsenic exposure and adiposity, which could promote arsenic-induced cardiometabolic disorders by mirroring the distinctive characteristics of age-associated sarcopenic obesity.

Antioxidant Supplementation in Childhood Obesity: A Path to Improved Metabolic Health?

Childhood obesity is linked to heightened oxidative stress, a key driver of endothelial dysfunction, inflammation, and metabolic complications. Antioxidants, including Vitamins C and E, are vital in neutralizing free radicals and mitigating oxidative damage. This non-systematic review examines the potential advantages of antioxidant supplementation in pediatric obesity, focusing on its effects on vascular health, insulin sensitivity, and inflammatory processes. Emerging data suggest that antioxidants may improve endothelial function, reduce blood pressure, and enhance metabolic homeostasis in obese children. However, the long-term efficacy and safety of antioxidant supplementation remain uncertain, necessitating further rigorous randomized controlled trials. A deeper understanding of antioxidants' role in pediatric obesity could unlock novel therapeutic approaches for managing obesity-related complications and improving children's overall health outcomes.

Leptin and Insulin in COPD: Unveiling the Metabolic-Inflammatory Axis-A Narrative Review

Chronic obstructive pulmonary disease (COPD) is a progressive and debilitating condition characterized by airflow limitations and systemic inflammation. The interaction between the metabolic and inflammatory pathways plays a key role in disease progression, with leptin and insulin emerging as pivotal metabolic regulators. Leptin, an adipokine that regulates energy homeostasis, and insulin, the primary regulator of glucose metabolism, are both altered in COPD patients. This narrative review provides an in-depth examination of the roles of leptin and insulin in COPD pathogenesis, focusing on the molecular mechanisms through which these metabolic regulators interact with inflammatory pathways and how their dysregulation contributes to a spectrum of extrapulmonary manifestations. These disturbances not only exacerbate COPD symptoms but also increase the risk of comorbidities such as metabolic syndrome, diabetes, cardiovascular disease, or muscle wasting. By exploring the underlying mechanisms of leptin and insulin dysregulation in COPD, this review underscores the significance of the metabolic-inflammatory axis, suggesting that restoring metabolic balance through leptin and insulin modulation could offer novel therapeutic strategies for improving clinical outcomes.

Adipokines: masterminds of metabolic inflammation

Adipose tissue is an immunologically active organ that controls host physiology, partly through the release of mediators termed adipokines. In obesity, adipocytes and infiltrating leukocytes produce adipokines, which include the hormones adiponectin and leptin and cytokines such as tumour necrosis factor and IL-1β. These adipokines orchestrate immune responses that are collectively referred to as metabolic inflammation. Consequently, metabolic inflammation characterizes metabolic disorders and promotes distinct disease aspects, such as insulin resistance, metabolic dysfunction-associated liver disease and cardiovascular complications. In this unifying concept, adipokines participate in the immunological cross-talk that occurs between metabolically active organs in metabolic diseases, highlighting the fundamental role of adipokines in obesity and their potential for therapeutic intervention. Here, we summarize how adipokines shape metabolic inflammation in mice and humans, focusing on their contribution to metabolic disorders in the setting of obesity and discussing their value as therapeutic targets.

An overview of obesity-related complications: The epidemiological evidence linking body weight and other markers of obesity to adverse health outcomes

Obesity is a highly prevalent chronic multisystem disease associated with shortened life expectancy due to a number of adverse health outcomes. Epidemiological data link body weight and parameters of central fat distribution to an increasing risk for type 2 diabetes, hypertension, fatty liver diseases, cardiovascular diseases including myocardial infarction, heart failure, atrial fibrillation, stroke, obstructive sleep apnoea, osteoarthritis, mental disorders and some types of cancer. However, the individual risk to develop cardiometabolic and other obesity-related diseases cannot entirely be explained by increased fat mass. Rather than excess fat accumulation, dysfunction of adipose tissue may represent the mechanistic link between obesity and adverse health outcomes. There are people living with obesity who seem to be protected against the premature development of cardiometabolic diseases. On the other hand, people with normal weight may develop typical obesity diseases upon dysfunction of adipose tissue and predominantly visceral fat distribution. The mechanisms linking impaired function of adipose tissue in people with obesity include adipocyte hypertrophy, altered cellular composition, limited expandability of safe subcutaneous fat stores, ectopic fat deposition in visceral depots, the liver and other organs, hypoxia, a variety of stresses, inflammatory processes, and the release of pro-inflammatory, diabetogenic and atherogenic signals. Genetic and environmental factors might contribute either alone or via interaction with intrinsic biological factors to variation in adipose tissue function. There are still many open questions regarding the mechanisms of how increased body weight causes obesity-related disorders and whether these pathologies could be reversed. Evidence-based weight loss interventions using behaviour change, pharmacological or surgical approaches have clarified the beneficial effects of realistic and sustained weight loss on obesity-related complications as hard outcomes. This review focusses on recent advances in understanding epidemiological trends and mechanisms of obesity-related diseases. PLAIN LANGUAGE SUMMARY: Obesity is a chronic complex and progressive disease characterized by excessive fat deposition that may impair health and quality of life. Worldwide, the number of adults living with obesity has more than doubled since 1990. Obesity may lead to reduced life expectancy, because it increases the risk for type 2 diabetes, cardiovascular diseases (e.g., myocardial infarction, high blood pressure, stroke), fatty liver diseases, musculoskeletal diseases, chronic respiratory diseases, depression and certain types of cancer. However, not every person with obesity develops these diseases. For better prevention and treatment, it is important to understand the mechanisms linking high fat mass to obesity related diseases. It has become clear that fat mass alone cannot explain the higher risk of obesity complications. People with obesity can have either high or low risk of developing complications. Compared to people with a low risk for obesity complications those with a high risk to develop obesity related diseases are characterized by higher central fat deposition in the abdominal region, on average bigger fat cells, higher number of immune cells in adipose tissue and altered signals released from adipose tissue that may directly affect the brain, liver, vasculature and other organs. Both inherited and environment factors may cause these abnormalities of adipose tissue function. However, weight loss through behaviour changes (e.g., lower calorie intake, higher physical activity), medications or obesity surgery can improve health, quality of life and reduce the risk for obesity related diseases.

Hypothalamus and brainstem circuits in the regulation of glucose homeostasis

The central nervous system (CNS) senses and integrates blood glucose status, regulating its levels through communication with peripheral organs. Since traditional wisdom holds that the hypothalamus primarily controls glucose homeostasis, the brainstem, although less studied, has been emerging as a key player in blood glucose metabolism. Although the brainstem is reciprocally wired with the hypothalamus, their interactions are crucial for glucose control. Here, we focus on classic discoveries and recent advancements of hypothalamic and brainstem nodes that regulate glucose homeostasis. Based on the current progress and development for central regulation of blood sugar, we propose that the circuitry and cellular mechanisms for how hypothalamus and brainstem coordinate in blood sugar regulation are crucial; hence, a deeper understanding of both nuclei could shed light on a future cure for diabetes.

Effect of housing density on cellular and humoral immunity, hematology in striped hamsters

Population density is one of the most important factors influencing immune function. Social stress induced by higher density may account for the immunosuppression according to the endocrine hypothesis. To test this hypothesis, male striped hamsters (Cricetulus barabensis) were classified into the One/Cage (n = 9), Two/Cage (n = 6), and Three/Cage (n = 9) groups, and the treatment lasted for 45 days. The titers of immunoglobin (Ig)G15 and IgM 10 were lower in the Two/Cage group compared to the One/Cage group, indicating that higher housing density suppressed humoral immunity. However, the masses of thymus and spleen, phytohaemagglutinin (PHA) responses at 6 h, 12 h, 24 h, 48 h, and 72 h after PHA injection, the titers of IgG 5, IgG10, IgM5, and IgM15 were all not affected by housing density. Blood glucose level was higher in the One/Cage group than the other two groups, leptin titers did not differ among the three groups, whereas corticosterone concentration was higher in the Two/Cage and Three/Cage groups than in the One/Cage group. Moreover, negative correlation was observed between corticosterone concentration and the titers of IgG5, IgG10, IgG15, and IgM10. These results suggested that humoral immunity was reduced by higher stress levels induced by higher housing density, which supported the endocrine hypothesis. White blood cell (WBC) count was higher in the Two/Cage group than in the One/Cage group, and intermediate granulocytes (MID) were higher in the Two/Cage group than in the One/Cage and Three/Cage groups, indicating the fight and injury might have arisen in the higher housing density.

Low Levels of Serum Ghrelin and Nesfatin-1 Are Associated With Anxiety Disorders in Children

Objectives

Because appetite-regulating hormones are implicated in neuronal survival, growth, and differentiation, they have been suggested to play a role in anxiety disorders. To date, few studies have focused on the association between these hormones and anxiety disorders in children. This study investigated the potential differences in leptin, ghrelin, and nesfatin-1 serum levels in drug-naïve children with anxiety disorders, including social anxiety disorder, separation anxiety disorder, and generalized anxiety disorder, and in healthy controls.

Methods

This study included 45 children (14 boys and 31 girls) with anxiety disorders and 35 healthy controls (13 boys and 22 girls) aged 8-18 years. The severity of anxiety disorders and additional symptoms were evaluated using the Revised Child Anxiety and Depression Scales-Child Version. Enzyme-linked immunosorbent assay (ELISA) was used to evaluate leptin, ghrelin, and nesfatin-1 serum levels.

Results

Leptin levels were significantly higher in children with anxiety disorders than in the control group, and ghrelin and nesfatin-1 levels were significantly lower in children with anxiety disorders than in the control group for girls and for the entire sample. However, only low nesfatin-1 levels were significantly associated with anxiety disorders in boys. In the entire sample, potential confounders such as age, sex, body mass index, and the severity of depressive symptoms were controlled for, and the results were the same for ghrelin and nesfatin-1 levels. However, the difference in leptin levels between groups was not significant.

Conclusion

These findings suggest that dysregulation of ghrelin and nesfatin-1 concentrations may be related to the etiopathogenesis of childhood anxiety disorders.

Synergistic Activation of LEPR and ADRB2 Induced by Leptin Enhances Reactive Oxygen Specie Generation in Triple-Negative Breast Cancer Cells

PURPOSE

Leptin interacts not only with leptin receptor (LEPR) but also engages with other receptors. While the pro-oncogenic effects of the adrenergic receptor β2 (ADRB2) are well-established, the role of leptin in activating ADRB2 in triple-negative breast cancer (TNBC) remains unclear.

MATERIALS AND METHODS

The pro-carcinogenic effects of LEPR were investigated using murine TNBC cell lines, 4T1 and EMT6, and a tumor-bearing mouse model. Expression levels of LEPR, NADPH oxidase 4 (NOX4), and ADRB2 in TNBC cells and tumor tissues were analyzed via western blot and quantitative real-time polymerase chain reaction. Changes in reactive oxygen species (ROS) levels were assessed using flow cytometry and MitoSox staining, while immunofluorescence double-staining confirmed the co-localization of LEPR and ADRB2.

RESULTS

LEPR activation promoted NOX4-derived ROS and mitochondrial ROS production, facilitating TNBC cell proliferation and migration, effects which were mitigated by the LEPR inhibitor Allo-aca. Co-expression of LEPR and ADRB2 was observed on cell membranes, and bioinformatics data revealed a positive correlation between the two receptors. Leptin activated both LEPR and ADRB2, enhancing intracellular ROS generation and promoting tumor progression, which was effectively countered by a specific ADRB2 inhibitor ICI118551. In vivo, leptin injection accelerated tumor growth and lung metastases without affecting appetite, while treatments with Allo-aca or ICI118551 mitigated these effects.

CONCLUSION

This study demonstrates that leptin stimulates the growth and metastasis of TNBC through the activation of both LEPR and ADRB2, resulting in increased ROS production. These findings highlight LEPR and ADRB2 as potential biomarkers and therapeutic targets in TNBC.

The effect of a leptin phenotype on weight change and energy expenditure responses to acute and prolonged energetic stressors

Leptin is a hormone produced by adipocytes that plays a crucial role in regulating energy homeostasis and body mass. Despite its close correlation with body fat, up to ∼40% of variation in plasma leptin concentration remains unexplained, allowing for the classification of a distinct "leptin phenotype." This leptin phenotype-characterized by either relatively high or relatively low leptin concentration relative to an individual's level of body fat-presents an intriguing opportunity to test whether relatively higher (compared with lower) leptin concentrations differentially affect energy expenditure, metabolic adaptation, and susceptibility to weight change in response to energy balance perturbations. To test this hypothesis, we characterized the energy expenditure and weight change response between the two leptin phenotypes (relatively high vs. low) using three distinct experimental contexts: a cross-sectional analysis (n = 104), acute (24-h) perturbations with fasting and overfeeding (n = 77), and chronic perturbations with 24-mo caloric restriction (n = 144) or 8-wk overfeeding (n = 28). Leptin phenotype did not explain variations in energy expenditure responses either in cross-sectional analyses or in response to acute or prolonged energetic stressors. Moreover, leptin phenotype was not a determinant of weight change in response to energy restriction or surplus, or subsequent weight recovery. These results suggest that classifying individuals based on a leptin phenotype does not allow to detect differential susceptibility to energy expenditure adaptations or weight change.NEW & NOTEWORTHY Leptin is linked to body fat, but unexplained variation remains. This study challenges the idea that distinct leptin phenotypes-characterized by relatively high or low leptin concentration for a given level of body fat-affects energy expenditure or weight change in response to acute or prolonged energy stressors. We found no association between leptin phenotypes and energy expenditure or weight change either cross-sectionally or in response to acute or prolonged over- or underfeeding.

Large-Scale Plasma Proteomics to Profile Pathways and Prognosis of Chronic Pain

While increasing peripheral mechanisms related to chronic pain, the plasma proteomics profile associated with it and its prognosis remains elusive. This study utilizes 2923 plasma proteins and chronic pain of 51 644 participants from UK Biobank and finds 474 proteins linked to chronic pain in six sites: head, neck or shoulder, back, stomach or abdominal, hip, and knee, with 11 proteins sharing across pain sites. The identified proteins are largely enriched in immune and metabolic pathways and highly expressed in tissues like lungs and small intestines. Phenome-wide analysis highlights the significance of pain-related proteome on diverse facets of human health, and in-depth Mendelian randomization validates 10 proteins (CD302, RARRES2, TNFRSF1B, BTN2A1, TNFRSF9, COL18A1, TNF, CD74, TNFRSF4, and BTN2A1) as markers of chronic pain. Furthermore, protein sets capable of classifying pain patients and healthy participants, particularly performing best in hip pain (area under curve, AUC = 0.725), are identified. Interestingly, the prediction of pain spreading over ten years achieves an AUC of 0.715, with leptin identified as a crucial predictor. This study delineates proteins associated with various pain conditions and identifies proteins capable of classifying pain and predicting pain spreading, offering benefits for both research and clinical practice.

Hypertrophic adipocytes increase extracellular vesicle-mediated lipid release and reprogram breast cancer cell metabolism

Obesity worsens cancer-specific survival and all-cause mortality for women diagnosed with breast cancer. Rich in adipose tissue, the breast exhibits increased adipocyte size in obesity, which correlates with poor prognosis. However, adipocyte size is highly heterogeneous as adipose tissue expands through both hyperplasia and hypertrophy; and adipocyte size can increase independently of weight gain. Despite these observations, the impact of adipocyte size on breast cancer cell behavior remains unclear due to insufficient approaches to isolate adipocytes based on size and maintain them in culture for mechanistic studies. Here, we develop strategies to culture size-sorted adipocytes from two mouse models of obesity and test their functional impact on tumor cell malignancy. We find that large adipocytes are transcriptionally distinct from small adipocytes and are enriched for gene sets related to adipose tissue dysfunction, including altered lipid processing. In coculture studies, large adipocytes promote lipid accumulation in breast cancer cells, and enhance their migration, proliferation, and aerobic metabolism in a manner dependent on fatty acid oxidation. These changes coincide with increased release of extracellular vesicles by large versus small adipocytes, which transfer lipid to recipient tumor cells. Moving forward, our findings suggest that adipocyte size could serve as a prognostic biomarker for women with breast cancer and help identify new therapeutic targets to advance clinical outcomes for these patients.

Leptin activates dopamine and GABA neurons in the substantia nigra via a local pars compacta-pars reticulata circuit

Adipose-derived leptin contributes to energy homeostasis by balancing food intake and motor output, but how leptin acts in brain motor centers remains poorly understood. We investigated the influence of leptin on neuronal activity in two basal ganglia nuclei involved in motor control: the substantia nigra pars compacta (SNc) and pars reticulata (SNr). Using a mouse reporter line to identify cells expressing leptin receptors (LepRs), we found that in both sexes, a majority of SNc dopamine neurons express a high level of LepR. Whole-cell recording in ex vivo midbrain slices from male wild-type mice showed that leptin activates SNc dopamine neurons directly and increases somatodendritic dopamine release. Although LepR expression in SNr GABA output neurons was low, leptin also activated these cells. Additional experiments showed that the influence of leptin on SNr neurons is indirect and involves D1 dopamine receptors and TRPC3 channels. Administration of leptin to male mice increased locomotor activity, consistent with activation of dopamine neurons in the SNc coupled to previously reported amplification of axonal dopamine release by leptin in striatal slices. These findings indicate that in addition to managing energy homeostasis through its actions as a satiety hormone, leptin also promotes axonal and somatodendritic dopamine release that can influence motor output.Significance statement Dopamine neurons regulate motivated behaviors, but how they are influenced by metabolic hormones, like leptin, is incompletely understood. We show here that leptin increases the activity of substantia nigra (SN) pars compacta dopamine neurons directly, and that this enhances somatodendritic dopamine release. Leptin also increases the activity of GABAergic neurons in the SN pars reticulata, but does so indirectly via D1 dopamine receptors activated by locally released dopamine. Consistent with increased nigral dopamine neuron activity and previous evidence showing that leptin amplifies striatal dopamine release, systemic leptin increases locomotor behavior. This increase in motor activity complements the well-established inhibitory effect of leptin on food intake and adds an additional dimension to the regulation of energy balance by this hormone.

A Leptin Receptor Mutation Which Impairs Fertility in Ewes Causes Delayed Puberty in Male and Female Mice

Reproductive function is tightly linked to nutritional status due to its high energetic demands. Leptin, a key adipose tissue-derived hormone signalling energy reserves to the brain, integrates metabolic status with the hypothalamic-pituitary-gonadal axis to ensure reproductive function is maintained or suppressed appropriately. Mutations in leptin or its receptor (LepR) are known to cause infertility and obesity in mice. In Davisdale ewes, 2 naturally occurring LepR mutations (R62C and P1019S) were associated with delayed puberty and subfertility, but their effects in males or in other species remain to be determined. This study examined the impact of analogous LepR mutations (A63C and P1018S) in mice using CRISPR-Cas9 gene editing. Puberty onset, adult fertility, and metabolic phenotypes were assessed in wild-type, heterozygous, and homozygous mutant mice. The A63C mutation, located in the extracellular domain of the receptor, resulted in increased body weight and adiposity in females, along with delays in puberty onset in both sexes. Despite these delays, adult reproductive function was maintained. Immunohistochemical analysis revealed no detectable reductions in leptin-induced pSTAT3, pERK1/2, or pmTOR signalling in the hypothalamic arcuate nucleus in either mutant line, indicating these pathways remain largely intact. These findings demonstrate the conserved importance of this region of the leptin receptor for puberty onset and adiposity across species, but also the resilience of leptin signalling in preserving reproductive function despite genetic variation.

Circulating microRNAs as Potential Biomarkers of Overweight and Obesity in Adults: A Narrative Review

In an obesogenic environment, such as the one we have been experiencing in recent decades, epigenetics provides answers to the relationship between hereditary and environmentally acquired patterns that have significantly contributed to the global rise in obesity prevalence. MicroRNA (miRNA) constitutes a diminutive non-coding small RNA molecule, 20 to 24 nucleotides in length, that functions as a regulator of gene regulation at the post-translational level. Circulating miRNAs (c-miRNAs) have been detected in multiple body fluids, including blood, plasma, serum, saliva, milk from breastfeeding mothers, and urine. These molecules hold significant therapeutic value and serve as extracellular biomarkers in metabolic diseases. They aid in the diagnosis and tracking of therapy responses, as well as dietary and physical habit modifications. Researchers have studied c-miRNAs as potential biomarkers for diagnosing and characterizing systemic diseases in people of all ages and backgrounds since then. These conditions encompass dyslipidemia, type 2 diabetes mellitus (T2DM), cardiovascular risk, metabolic syndrome, cardiovascular diseases, and obesity. This review therefore analyzes the usefulness of c-miRNAs as therapeutic markers over the past decades. It also provides an update on c-miRNAs associated with general obesity and overweight, as well as with the most prevalent pathologies in the adult population. It also examines the effect of different nutritional approaches and physical activity regarding the activity of miRNAs in circulation in adults with overweight or general obesity. All of this is done with the aim of evaluating their potential use as biomarkers in various research contexts related to overweight and obesity in adults.

Advances in energy balance & metabolism circuitry

Advancements in informatics, genetics, and neuroscience have greatly expanded our understanding of how the central nervous system (CNS) regulates energy balance and metabolism. This chapter explores the key neural circuits within the hypothalamus and brainstem that integrate behavioral and physiological processes to maintain metabolic homeostasis. It also examines the dynamic interplay between the CNS and peripheral organs, mediated through hormonal and neuronal signals, which fine-tune appetite, energy expenditure, and body weight. Furthermore, we highlight groundbreaking research that unveils molecular and cellular pathways governing energy regulation, representing a new frontier in addressing obesity and metabolic disorders. Innovative approaches, such as neurogenetic and neuromodulation techniques, are explored as promising strategies for improving weight management and metabolic health. By providing a comprehensive perspective on the mechanisms underlying energy balance, this chapter underscores the transformative potential of emerging therapeutic innovations.

On the causes of obesity and its treatment: The end of the beginning

Over the last 30 years, our understanding of the causes of obesity has been transformed, and new, highly effective medicines for reducing weight have been developed. This remarkable progress marks an end and a beginning. By establishing that obesity is a biologic disorder amenable to scientific inquiry and rational drug development, simplistic notions about its causes and treatment should be laid to rest. The future holds the promise that additional therapeutic approaches for inducing or maintaining weight loss will be developed, and that these treatments will be tailored to different subgroups to potentially address the pathogenic mechanisms.

Butyrate Ameliorates Graves' Orbitopathy Through Regulating Orbital Fibroblast Phenotypes and Gut Microbiota

Purpose

Graves' orbitopathy (GO), the common extrathyroidal complication of Graves' disease (GD), is characterized by orbital fibroblast stimulation, adipogenesis, and hyaluronan production. Recently, gut microbiota and its metabolites have garnered attention for their possible involvement in GO.

Methods

This study utilized an animal model of GO and examined the effects of butyrate treatment on orbital fibroblast cells and gut microbiota. Ex vivo experiments were performed using orbital fibroblasts derived from healthy patients' and patients' with GO orbital tissue to evaluate vitality, activation, and adipogenesis in response to butyrate treatment. Gut microbiota diversity was also analyzed in butyrate-treated and untreated GO mice.

Results

In human orbital fibroblasts, butyrate treatment dramatically decreased the vitality of GO-derived fibroblasts without harming normal fibroblasts. Butyrate prevented activation and fibrotic processes induced by transforming growth factor beta 1 (TGF-β1) in GO and normal fibroblasts. Additionally, butyrate reduced lipid droplet formation and downregulated lipogenic markers in GO and normal orbital fibroblasts, inhibiting adipogenesis. In the GO mouse model, butyrate therapy improved orbital histological abnormalities and normalized serum thyroid hormone and antibody levels. The intestinal microbiome of butyrate-treated GO mice also changed significantly, with a reduction in certain bacteria (Bifidobacterium, GCA-900066575, and Parabacteroides) and an increase in others (Bacteroides and Rikenellaceae_RC9).

Conclusions

Butyrate ameliorates several of the symptoms of GO, lowering GO orbital fibroblast viability, adipogenesis, and TGF-β1-induced fibrosis without damaging normal fibroblasts. Butyrate normalizes thyroid function in a GO mouse model, improves histopathological alterations, and transforms gut microbiota populations, proving its potential in treating GO through the gut-thyroid axis.

Pathogenic variants in the fibronectin type III domain of leptin receptor: Molecular dynamics simulation and structural analysis

Several case reports have identified leptin receptor (LEPR) variants associated with severe obesity in humans. However, the structure of LEPR has only been partially understood until recently, and few studies have investigated the detrimental effects of these variants on the protein's three-dimensional structure. Notably, fibronectin type III (FnIII) domains play a crucial role in signal transduction. In this study, we examined the impact of 10 variants within the FnIII domains on LEPR structure using molecular dynamics (MD) simulations and structural analysis. Our 300 ns MD simulations revealed that the C604S variant, which disrupts a key disulfide bond, significantly increased the overall root-mean-square deviation (RMSD) of the FnIII-2 and FnIII-3 domains, indicating destabilization of the interdomain rigidity required for proper signaling. Variants such as P639L, N718S, and W646C also induced abnormal bending and rotational misalignment between the FnIII domains, contributing to interdomain destabilization. Structural analysis identified folding nuclei and demonstrated that L662S, W664R, H684P, and S723F destabilize the internal domain. Variants affecting interdomain resulted in lower-than-expected damage prediction scores by bioinformatics tools. This study is expected to contribute to the elucidation of the disease-causing mechanisms of missense variants in the leptin receptor.

Diabetic retinopathy features in lund MetS rats

The Lund MetS rat (BBDR.cg-Leprdb/db.cp/LundRj) is a novel animal model that has a congenic leptin receptor deficiency (LepR-/-) and males exhibit a variety of metabolic abnormalities mimicking the human metabolic syndrome, including hyperglycemia, dyslipidemia, severe obesity, and a type 2 diabetes-like condition from 14 weeks of age. However, whether Lund MetS rats (LM rats) develop diabetic retinopathy is still unknown. The purpose is to investigate the features of diabetic retinopathy in this model. In this study, male LM rats aged 15 and 30 weeks were analyzed for pathological retinal changes, including vasculopathy, inflammation, reactive gliosis, oxidative stress, and neurodegeneration features on the retinas by histological, immunohistochemical, and gene and protein expression analysis. Compared with the non-diabetic LM rats, diabetic LM rats, mainly at 30 weeks of age, had a decrease in retinal thickness and loss of retinal ganglion cells and photoreceptors, indicating retinal neurodegeneration. They also presented an increase in VEGF-A expression, Endra, Icam-1, Vcam-1, and Endrb vascular genes, and albumin suggesting neurovascular unit dysfunction. Furthermore, retinas presented reactive gliosis and infiltration of microglia, TNF-α-positive vessels and expressed elevated levels of inflammatory genes Tnf-α, IL-18 and IL-6, and oxidative stress markers Sod2 and 8-hydroxy-2-deoxyguanosine (8-OHdG). Our results suggest that diabetic LM rats reproduce the early neurodegenerative and altered neuro-vascular features that also occur in the human diabetic eye.

The expanding landscape of genetic causes of obesity

Obesity and weight regulation disorders are determined by the combined effects of genetics and environment. Polygenic obesity results from the combination of common variants in several genes which predisposes the individual to obesity and its related complications. In contrast, monogenic obesity results from changes in single genes, especially those in leptin-melanocortin pathway, and presents with early onset severe obesity, with or without other syndromic features. Rare variants in melanocortin 4 receptor are the commonest form of monogenic obesity. In addition, structural variation in small or large segments of chromosomes may also present with syndromic forms of obesity. Prader-Willi Syndrome, caused by imprinting errors in chromosome 15q11-13, is the most prevalent genetic cause of severe hyperphagia and obesity. With the advances in technologies, the past decade has witnessed a revolution in the identification of novel genetic causes of obesity, primarily in genes related to the leptin melanocortin pathway. The availability of safe melanocortin analogs holds the potential for targeted therapies for some of these disorders. This review summarizes known and novel rare genetic forms of obesity, along with approaches for the clinical investigation of copy number and sequence variants. The goal is to provide a reference for practicing clinicians to encourage genetic testing in obesity. IMPACT: What does this article add to the existing literature? Genetic obesity is an expanding frontier with potential to change management. Here, we summarize current information on the genetic causes of obesity and provide guidance for genetic testing. Emerging treatments may provide targeted precise treatment and change management practices.

Management of Obesity-Related Genetic Disorders

Obesity-related genetic disorders are marked by severe, early-onset obesity caused by mutations that disrupt key biological mechanisms regulating hunger, energy balance, and fat storage. These disorders commonly impact systems such as the hypothalamic leptin-melanocortin signaling network, which plays a crucial role in controlling appetite and body weight, mainly through the melanocortin-4 receptor (MC4R) pathway. This review explores current management strategies and emerging therapies for genetic obesity disorders, highlighting the importance of treatment approaches and expanded genetic diagnostics to improve outcomes for affected individuals.

[Intestinal gluconeogenesis : When the intestine produces glucose to prevent obesity and hepatic steatosis]

Intestinal gluconeogenesis refers to the ability of the gut to produce glucose outside of meals. By initiating a gut-brain neural axis, its activation by dietary fiber or protein improves the regulation of energy balance. Recently, the creation of a genetic activation model of intestinal gluconeogenesis has demonstrated its anti-obesity, anti-diabetes and anti-hepatic steatosis effects. Interestingly, it increases thermogenesis in brown adipose tissue, thereby promoting energy expenditure and contributing to the fight against obesity. Therefore, targeting intestinal gluconeogenesis could be an innovative strategy to address metabolic diseases such as hepatic steatosis and diabetes, paving the way to new therapeutic approaches.

Leptin and Leptin Signaling in Multiple Sclerosis: A Narrative Review

Obesity, a pandemic health problem, is now considered as a chronic inflammatory state, related to many autoimmune diseases, such as multiple sclerosis. Thus, adipokines, inflammatory mediators secreted by adipose tissue, play an important role modulating the immune response. In this context, obesity, especially during adolescent age, seems to be a key factor for the development of multiple sclerosis. Leptin, the main pro-inflammatory adipokine secreted by the adipose tissue, has been found increased in patients with multiple sclerosis and is able to regulate the immune system promoting a pro-inflammatory response. Leptin signaling in both innate and adaptative immune cells might have immunomodulatory effects in the context of multiple sclerosis. In this way, leptin has been found to produce a Th1 and Th17 response, increasing M1 macrophages and decreasing regulatory T cells and Th2 response. Moreover, circulating inflammatory adipokines, such as leptin, have been found in people with multiple sclerosis. In the present work, we are reviewing literature to update the body of knowledge regarding the role of obesity and leptin in multiple sclerosis.

Characterization of Leptin and Leptin Receptor Gene in the Siberian Sturgeon (Acipenser baerii): Molecular Cloning, Tissue Distribution, and Its Involvement in Feeding Regulation

Leptin is an adipokine known as a regulator of feeding and metabolism in mammals. Previous studies on fish have revealed its role in food intake regulation in limited teleosts. However, its specific function in Siberian sturgeon, an ancient Chondrostei fish, remains poorly understood. This study represents the first successful cloning of sequences for leptin and leptin receptors in Siberian sturgeon, achieved using RT-PCR. The predicted leptin sequence in this species consists of 168 amino acids that exhibit low identity with other fish species, except within the Acipenseriformes order. Tissue distribution analysis revealed a high expression of Siberian sturgeon leptin mRNA in the liver and lepr mRNA in the hypothalamus. Fasting differentially affected the expression of leptin and lepr mRNA, with decreased levels in the hypothalamus and increased levels in the liver (leptin: 3-15 days; lepr: 6-15 days). Recombinant Siberian sturgeon leptin (Ssleptin) was produced via E. coli expression, and intraperitoneal injection (100 ng/g BW) significantly inhibited food intake. The anorectic effect was correlated with changes in hypothalamic gene expression, including downregulation of orexigenic factors (agrp, orexin, npy, and ghrelin) and upregulation of anorexigenic factors (pomc, mch, and insulin). Meanwhile, the peripheral administration of Ssleptin promoted the expression of resistin in the liver and concurrently increased cck and pyy mRNA levels in the valvular intestine. Furthermore, Ssleptin injection stimulated the expression of hypothalamic lepr, jak2, akt, and ampkα2 mRNA. These findings suggest that leptin plays a significant role in the feeding control of Siberian sturgeon and provide new insights into the evolutionary function of leptin in fish.

Computational modeling of human genetic variants in mice

Mouse models represent a powerful platform to study genes and variants associated with human diseases. While genome editing technologies have increased the rate and precision of model development, predicting and installing specific types of mutations in mice that mimic the native human genetic context is complicated. Computational tools can identify and align orthologous wild-type genetic sequences from different species; however, predictive modeling and engineering of equivalent mouse variants that mirror the nucleotide and/or polypeptide change effects of human variants remains challenging. Here, we present H2M (human-to-mouse), a computational pipeline to analyze human genetic variation data to systematically model and predict the functional consequences of equivalent mouse variants. We show that H2M can integrate mouse-to-human and paralog-to-paralog variant mapping analyses with precision genome editing pipelines to devise strategies tailored to model specific variants in mice. We leveraged these analyses to establish a database containing > 3 million human-mouse equivalent mutation pairs, as well as in silico-designed base and prime editing libraries to engineer 4,944 recurrent variant pairs. Using H2M, we also found that predicted pathogenicity and immunogenicity scores were highly correlated between human-mouse variant pairs, suggesting that variants with similar sequence change effects may also exhibit broad interspecies functional conservation. Overall, H2M fills a gap in the field by establishing a robust and versatile computational framework to identify and model homologous variants across species while providing key experimental resources to augment functional genetics and precision medicine applications. The H2M database (including software package and documentation) can be accessed at https://human2mouse.com.