Leptin

Obstructive Sleep Apnea-Hypopnea Syndrome (OSAHS) Combined With Obesity Leads to Elevated Thyroid Hormone Levels

Introduction: Research indicates a strong link between obesity and alterations in thyroid function among patients diagnosed with obstructive sleep apnea-hypopnea syndrome (OSAHS). Our study aims to investigate the thyroid hormone levels in patients with OSAHS combined with obesity. It seeks to elucidate the changes in thyroid hormones and their potential metabolic risks in these patients, thereby further clarifying the role and clinical significance of thyroid function alterations in OSAHS complicated by obesity. Methods: One hundred and thirty-four patients were divided into four groups, including the normal group, the obesity group, the OSAHS with the obesity group, and the OSAHS group. Serum levels of free triiodothyronine (FT3), free thyroxine (FT4), and thyroid-stimulating hormone (TSH) were analyzed using electrochemiluminescence immunoassay. Clinical metabolic parameters (total cholesterol [TC], triglycerides [TG], high-density lipoprotein cholesterol [HDL-C], low-density lipoprotein cholesterol [LDL-C]) and sleep respiratory monitoring indicators (apnea-hypopnea index [AHI], longest duration of sleep apnea [TAmax], oxygen desaturation index [ODI], mean oxygen saturation [M-SaO2], and lowest oxygen saturation [L-SaO2]) were also recorded. Results: The OSAHS with the obesity group demonstrated elevated FT3, TSH, and ODI levels but lower L-SaO2 level than other groups, and the levels of TG and LDL-C were higher than those in the OSAHS group and the normal group. Additionally, TSH level was positively correlated with LDL-C and BMI, but negatively correlated with L-SaO2. In the obesity group, FT3, TSH, TG, ODI, and TAmax levels were higher, while L-SaO2 and M-SaO2 were lower than those in the normal group. Conclusions: Patients with both OSAHS and obesity are at higher risk of developing subclinical hypothyroidism, with LDL-C, BMI, and L-SaO2 levels likely contributing to changes in TSH levels.

Obstructive Sleep Apnea‐Hypopnea Syndrome (OSAHS) Combined With Obesity Leads to Elevated Thyroid Hormone Levels

Introduction: Research indicates a strong link between obesity and alterations in thyroid function among patients diagnosed with obstructive sleep apnea‐hypopnea syndrome (OSAHS). Our study aims to investigate the thyroid hormone levels in patients with OSAHS combined with obesity. It seeks to elucidate the changes in thyroid hormones and their potential metabolic risks in these patients, thereby further clarifying the role and clinical significance of thyroid function alterations in OSAHS complicated by obesity.

Methods: One hundred and thirty‐four patients were divided into four groups, including the normal group, the obesity group, the OSAHS with the obesity group, and the OSAHS group. Serum levels of free triiodothyronine (FT3), free thyroxine (FT4), and thyroid‐stimulating hormone (TSH) were analyzed using electrochemiluminescence immunoassay. Clinical metabolic parameters (total cholesterol [TC], triglycerides [TG], high‐density lipoprotein cholesterol [HDL‐C], low‐density lipoprotein cholesterol [LDL‐C]) and sleep respiratory monitoring indicators (apnea‐hypopnea index [AHI], longest duration of sleep apnea [TAmax], oxygen desaturation index [ODI], mean oxygen saturation [M‐SaO2], and lowest oxygen saturation [L‐SaO2]) were also recorded.

Results: The OSAHS with the obesity group demonstrated elevated FT3, TSH, and ODI levels but lower L‐SaO2 level than other groups, and the levels of TG and LDL‐C were higher than those in the OSAHS group and the normal group. Additionally, TSH level was positively correlated with LDL‐C and BMI, but negatively correlated with L‐SaO2. In the obesity group, FT3, TSH, TG, ODI, and TAmax levels were higher, while L‐SaO2 and M‐SaO2 were lower than those in the normal group.

Conclusions: Patients with both OSAHS and obesity are at higher risk of developing subclinical hypothyroidism, with LDL‐C, BMI, and L‐SaO2 levels likely contributing to changes in TSH levels.

Novel perspectives on leptin in osteoarthritis: Focus on aging

Osteoarthritis (OA) is a common chronic joint disease characterized by articular cartilage degeneration, subchondral sclerosis, synovitis, and osteophyte formation. OA is associated with disability and impaired quality of life, particularly among the elderly. Leptin, a 16-kD non-glycosylated protein encoded by the obese gene, is produced on a systemic and local basis in adipose tissue and the infrapatellar fat pad located in the knee. The metabolic mechanisms employed by leptin in OA development have been widely studied, with attention being paid to aging as a corroborative risk factor for OA. Hence, in this review, we have attempted to establish a potential link between leptin and OA, by focusing on aging-associated mechanisms and proposing leptin as a potential diagnostic and therapeutic target in aging-related mechanisms of OA that may provide fruitful guidance and emphasis for future research.

Elevated serum leptin may be associated with disease activity and secondary osteoporosis in Chinese patients with rheumatoid arthritis

INTRODUCTION

Rheumatoid arthritis (RA) is a systemic chronic autoimmune disease in adults that is associated with significant joint issues and systemic inflammation. One of the signs of bone damage in RA is osteoporosis (OP). Leptin is an inflammatory protein that has been reported to be related to RA. The potential relationships among leptin, disease activity, and OP in Chinese patients with RA are not well known.

METHODS

In total, 245 patients with RA and 120 healthy controls were included in this study. Detailed data on the clinical characteristics and laboratory features were collected. Information about physical activity and functional status was recorded using specific questionnaires. Bone mineral density (BMD) was measured by dual-energy X-ray absorptiometry (DXA). The MECALL castor-50-hf model X-ray scanner was used for the two-hand (including wrist) photographs.

RESULTS

Serum leptin levels differed significantly between the RA group and healthy control subjects (1.27/3.29 vs. 0.17/0.24, Z=13.29, P<0.001). The positive rate of leptin protein in RA patients was 86.35%, which was higher than that in controls (19.55%) (χ2=28.51, P<0.001). Pearson's correlation test showed that morning stiffness, disease duration, joint swelling, joint tenderness, swollen joint count (SJC), tender joint count (TJC), health assessment questionnaire (HAQ) score, and Sharp-van der Heijde method (Sharp) score were positively correlated with the level of serum leptin (r=0.212, r=0.312, r=0.322, r=0.501, r=0.291, r=0.334, P<0.05). There was a clear increasing trend in the level of serum leptin according to the different disease activity scores and in the 28 joint activity (DAS28) groups (F=13.936, P<0.001). Elevated leptin was a risk factor for increased disease activity and OP according to logistic regression analysis. The median leptin level differed significantly between the normal bone mass group, osteopenia group, and OP group (P<0.001). An increased serum leptin level was a risk factor for RA-induced osteoporosis according to logistic regression analysis (P<0.001).

CONCLUSION

These results suggest that the level of serum leptin is associated with disease activity and secondary OP among Chinese patients with RA. Key Points • Serum leptin levels in RA patients are higher than those in normal control group. • Leptin was associated with disease activity. • Leptin was associated with the occurrence of systemic osteoporosis and affects bone erosion in RA patients.

Increased RBP4 and Asprosin Are Novel Contributors in Inflammation Process of Periodontitis in Obese Rats

There is a significant comorbidity between obesity and periodontitis, while adipokines are pivotal in the immunoinflammatory process, which may play a role in this special relationship. We aimed to assess the effect of adipokines as mediators in the progression of periodontitis in obese Sprague Dawley rats. Rats were divided into four groups: normal body weight with and without periodontitis and obesity with and without periodontitis. Experimental obesity and periodontitis were induced by a high-fat diet or ligaturing, and the effect was measured using metabolic and micro-computed tomography analysis and histological staining. Compared with the other three groups, the group of periodontitis with obesity (OP) had the heaviest alveolar bone absorption, the largest increase in osteoclasts, the utmost inflammatory cell infiltration and the highest expressions of pro-inflammatory cytokines and nuclear factor-kappa B ligand (RANKL); meanwhile, its expression of the osteogenesis-related gene was the lowest among the four groups. The expressions of leptin, visfatin, resistin, retinol-binding protein 4 (RBP4) and asprosin were upregulated, while adiponectin was decreased significantly in OP. The strong positive associations between the periodontal or circulating levels of RBP4 (or asprosin) and the degree of alveolar resorption in experimental periodontitis and obese rats were revealed. The upregulated expression of inflammation biomarkers, the corresponding degradation in connective tissue and the generation of osteoclasts in periodontitis were activated and exacerbated in obesity. The elevated level of RBP4/asprosin may contribute to a more severe periodontal inflammatory state in obese rats.

Visceral adipose tissue and residual cardiovascular risk: a pathological link and new therapeutic options

Obesity is a heterogeneous disease that affects almost one-third of the global population. A clear association has been established between obesity and cardiovascular disease (CVD). However, CVD risk is known to be related more to the local distribution of fat than to total body fat. Visceral adipose tissue (VAT) in particular has a high impact on CVD risk. This manuscript reviews the role of VAT in residual CV risk and the available therapeutic strategies for decreasing residual CV risk related to VAT accumulation. Among the many pathways involved in residual CV risk, obesity and particularly VAT accumulation play a major role by generating low-grade systemic inflammation, which in turn has a high prognostic impact on all-cause mortality and myocardial infarction. In recent years, many therapeutic approaches have been developed to reduce body weight. Orlistat was shown to reduce both weight and VAT but has low tolerability and many drug-drug interactions. Naltrexone-bupropion combination lowers body weight but has frequent side effects and is contraindicated in patients with uncontrolled hypertension. Liraglutide and semaglutide, glucagon-like peptide 1 (GLP-1) agonists, are the latest drugs approved for the treatment of obesity, and both have been shown to induce significant body weight loss. Liraglutide, semaglutide and other GLP-1 agonists also showed a positive effect on CV outcomes in diabetic patients. In addition, liraglutide showed to specifically reduce VAT and inflammatory biomarkers in obese patients without diabetes. GLP-1 agonists are promising compounds to limit inflammation in human visceral adipocytes.

Protein biomarkers in multiple sclerosis

This review aimed to elucidate protein biomarkers in body fluids, such as blood and cerebrospinal fluid (CSF), to identify those that may be used for early diagnosis of multiple sclerosis (MS), prediction of disease activity, and monitoring of treatment response among MS patients. The potential biomarkers elucidated in this review include neurofilament proteins (NFs), glial fibrillary acidic protein (GFAP), leptin, brain-derived neurotrophic factor (BDNF), chitinase-3-like protein 1 (CHI3L1), C-X-C motif chemokine 13 (CXCL13), and osteopontin (OPN), with each biomarker playing a different role in MS. GFAP, leptin, and CHI3L1 levels were increased in MS patient groups compared to the control group. NFs are the most studied proteins in the MS field, and significant correlations with disease activity, future progression, and treatment outcomes are evident. GFAP CSF level shows a different pattern by MS subtype. Increased concentration of CHI3L1 in the blood/CSF of clinically isolated syndrome (CIS) is an independent predictive factor of conversion to definite MS. BDNF may be affected by chronic progression of MS. CHI3L1 has potential as a biomarker for early diagnosis of MS and prediction of disability progression, while CXCL13 has potential as a biomarker of prognosis of CIS and reflects MS disease activity. OPN was an indicator of disease severity. A periodic detailed patient evaluation should be performed for MS patients, and broadly and easily accessible biomarkers with higher sensitivity and specificity in clinical settings should be identified.

Preventive strategy for nonalcoholic fatty liver disease-related hepatocellular carcinoma

The incidence of hepatocellular carcinoma (HCC) associated with nonalcoholic fatty liver disease (NAFLD) has been increasing worldwide, including Asia. Most patients with NAFLD-related HCC are at a much-advanced stage and older age at the time of diagnosis than those with virus-related HCC because they have not undergone HCC surveillance. This review provides an overview of the mechanism of hepatocarcinogenesis in NAFLD, preventive strategies for NAFLDrelated HCC, and strategies for the surveillance of patients with NAFLD.

Emerging roles of leptin in Parkinson's disease: Chronic inflammation, neuroprotection and more?

An increasing body of experimental evidence implicates a relationship between immunometabolic deterioration and the progression of Parkinson's disease (PD) with a dysregulation of central and peripheral neuroinflammatory networks mediated by circulating adipokines, in particular leptin. We screened the current literature on the role of adipokines in PD. Hence, we searched known databases (PubMed, MEDLINE/OVID) and reviewed original and review articles using the following terms: "leptin/ObR", "Parkinson's disease", "immune-metabolism", "biomarkers" and "neuroinflammation". Focusing on leptin, we summarize and discuss the existing in vivo and in vitro evidence on how adipokines may be protective against neurodegeneration, but at the same time contribute to the progression of PD. These components of the adipose brain axis represent a hitherto underestimated pathway to study systemic influences on dopaminergic degeneration. In addition, we give a comprehensive update on the potential of adjunctive therapeutics in PD targeting leptin, leptin-receptors, and associated pathways. Further experimental and clinical trials are needed to elucidate the mechanisms of action and the value of central and peripheral adipose-immune-metabolism molecular phenotyping in order to develop and validate the differential roles of different adipokines as potential therapeutic target for PD patients.

Depletion of Zinc Causes Osteoblast Apoptosis with Elevation of Leptin Secretion and Phosphorylation of JAK2/STAT3

Zinc (Zn) has been reported to mediate leptin secretion, and thus leptin can be an important candidate molecule linking Zn with bone formation. The present study investigated whether zinc deficiency induces leptin secretion by activating a JAK2/STAT3 signaling pathway and leads to osteoblastic apoptosis. MC3T3-E1 cells were incubated for 24 h in normal osteogenic differentiation medium (OSM) or OSM treated with either 1 μM (Low Zn) or 15 μM (High Zn) of ZnCl₂ containing 5 μM TPEN (Zn chelator). Our results demonstrated that low Zn stimulated extracellular leptin secretion and increased mRNA and protein expression of leptin in osteoblastic MC3T3-E1 cells. The OB-Rb (long isoform of leptin receptor) expressions were also elevated in osteoblasts under depletion of Zn. Leptin-signaling proteins, JAK2 and p-JAK2 in the cytosol of low Zn osteoblast conveyed leptin signaling, which ultimately induced higher p-STAT3 expression in the nucleus. Apoptotic effects of JAK2/STAT3 pathway were shown by increased caspase-3 in low Zn osteoblasts as well as apoptotic morphological features observed by TEM. Together, these data suggest that low Zn modulates leptin secretion by activating JAK2/STAT3 signaling pathway and induces apoptosis of osteoblastic MC3T3-E1 cells.

Hunger Hormones in Disruptive Mood Dysregulation Disorder in Adolescents: An Exploratory Study

Background:

Hunger hormones, including ghrelin and leptin, are associated with appetitive behaviors in various psychiatric disorders. Biochemical and hormonal status in disruptive mood dysregulation disorder (DMDD) in adolescents is largely unexplored.

Objectives:

The study aimed to assess levels of leptin and ghrelin and find their association with lipid profiles in adolescents with DMDD.

Methods:

Twenty adolescents with a DSM 5 diagnosis of DMDD with age and gender-matched 19 healthy controls were recruited, followed by clinical assessment. They were assessed for leptin, ghrelin, and lipid profiles, respectively.

Results:

Adolescents with DMDD were comparable in age, education, family income, domicile status, psychiatric illness in the family, and body mass index (BMI) with matched controls. There was no difference in mean lipid profile and ghrelin in both groups. However, the DMDD group had statistically significant higher mean level of leptin as compared to the control group (t=1.84, p < 0.05). As measured by the Modified Overt Aggression Scale in DMDD, aggression showed a significant positive correlation with measures of lipid profile.

Conclusion:

Adolescents with DMDD have elevated serum leptin levels. Further research is needed to confirm this finding.

Emerging Biomarkers of Multiple Sclerosis in the Blood and the CSF: A Focus on Neurofilaments and Therapeutic Considerations

INTRODUCTION

Multiple Sclerosis (MS) is the most common immune-mediated chronic neurodegenerative disease of the central nervous system (CNS) affecting young people. This is due to the permanent disability, cognitive impairment, and the enormous detrimental impact MS can exert on a patient's health-related quality of life. It is of great importance to recognise it in time and commence adequate treatment at an early stage. The currently used disease-modifying therapies (DMT) aim to reduce disease activity and thus halt disability development, which in current clinical practice are monitored by clinical and imaging parameters but not by biomarkers found in blood and/or the cerebrospinal fluid (CSF). Both clinical and radiological measures routinely used to monitor disease activity lack information on the fundamental pathophysiological features and mechanisms of MS. Furthermore, they lag behind the disease process itself. By the time a clinical relapse becomes evident or a new lesion appears on the MRI scan, potentially irreversible damage has already occurred in the CNS. In recent years, several biomarkers that previously have been linked to other neurological and immunological diseases have received increased attention in MS. Additionally, other novel, potential biomarkers with prognostic and diagnostic properties have been detected in the CSF and blood of MS patients.

AREAS COVERED

In this review, we summarise the most up-to-date knowledge and research conducted on the already known and most promising new biomarker candidates found in the CSF and blood of MS patients.

DISCUSSION

the current diagnostic criteria of MS relies on three pillars: MRI imaging, clinical events, and the presence of oligoclonal bands in the CSF (which was reinstated into the diagnostic criteria by the most recent revision). Even though the most recent McDonald criteria made the diagnosis of MS faster than the prior iteration, it is still not an infallible diagnostic toolset, especially at the very early stage of the clinically isolated syndrome. Together with the gold standard MRI and clinical measures, ancillary blood and CSF biomarkers may not just improve diagnostic accuracy and speed but very well may become agents to monitor therapeutic efficacy and make even more personalised treatment in MS a reality in the near future. The major disadvantage of these biomarkers in the past has been the need to obtain CSF to measure them. However, the recent advances in extremely sensitive immunoassays made their measurement possible from peripheral blood even when present only in minuscule concentrations. This should mark the beginning of a new biomarker research and utilisation era in MS.

The relationships between leptin levels in maternal serum and breast milk of mothers and term infants

BACKGROUND

Leptin in breast milk play a significant role in metabolic programming.

OBJECTIVE

The aim of this study to evaluate the relationship between leptin levels in maternal serum and breast milk, and certain anthropometric measurements of infants and mothers.

METHODS

This study was conducted with 65 females and term infants. Anthropometric measurements of the mothers and the infants were obtained on the first, third, and sixth months, and leptin levels in maternal serum and breast milk were measured.

RESULTS

In this study, leptin levels in breast milk were positively correlated with leptin levels in maternal serum while the leptin levels in breast milk were lower than the serum leptin levels. It was also determined that mothers' body weights, BMI values, waist and hip circumferences were increased in a statistically significant way in terms of the months (p < .001). It was discovered that all the anthropometric measurements of the mothers were positively correlated with leptin levels in breast milk and maternal serum in all the months (p < .001). Furthermore, it was determined that the body weights of the infants in certain months were negatively correlated with leptin levels in breast milk and maternal serum while the lengths of the infants were positively correlated with leptin levels in breast milk and maternal serum (p < .05).

CONCLUSIONS

This study was determined that leptin levels in breast milk and maternal serum were related to anthropometric measurements of both mothers and infants. Future studies with larger populations are needed to understand the long-term consequences of leptin metabolism comprehensively.Key messagesThis study was determined that breast milk leptin level and maternal serum leptin level demonstrated a positive correlation, and breast milk leptin level was lower than maternal serum leptin level.Mothers' anthropometric measurements were positively correlated with leptin levels in breast milk and maternal serum in all the months.There was mostly a negative correlation between breast milk leptin level and infant body weight.

Identification of Neuropeptides as Potential Crosstalks Linking Down Syndrome and Periodontitis Revealed by Transcriptomic Analyses

Background

This bioinformatics study was aimed to investigate the relationship between periodontitis (PD) and Down Syndrome (DS) regarding potential crosstalk genes, related neuropeptides, and biological processes.

Methods

Data for PD (GSE23586, GSE10334 and GSE16134) and DS (GSE35665) were downloaded from NCBI Gene Expression Omnibus (GEO). Following normalization and merging of PD data, differential expression analysis was performed (p value < 0.05 and ∣log FC | ≥0.5). The common deregulated genes between PD and DS were considered as crosstalk genes. The significantly differentially expressed genes were used to construct the coexpression network and to further identify coexpression gene modules. To acquire the significant modules, the significant expression level of genes in the module was used to analyze the enrichment of genes in each module. Neuropeptides were assessed from NeuroPedia database. Neuropeptide genes and crosstalk genes were merged and mapped into PPI network, and the correlation coefficient (Spearman) was determined for the crosstalk genes.

Results

138 crosstalk genes were predicted. According to the functional enrichment analysis, these genes significantly regulated different biological processes and pathways. In enrichment analysis, the significant module of DS was pink module, and turquoise module was significant in PD. Four common crosstalk genes were acquired, i.e., CD19, FCRL5, FCRLA, and HLA-DOB. In the complex network, INS and IGF2 interacted with CASP3 and TP53, which commonly regulated the MAPK signaling pathway. Moreover, the results showed that TP53 interacted with IGF2 and INS inducing the dysregulation of PI3K-Akt signaling pathway. UBL was positively correlated with crosstalk genes in both diseases. LEP was revealed to be both a neuropeptide and crosstalk gene and was positively correlated with other crosstalk genes.

Conclusion

Different crosstalk genes, related neuropeptides, and biological pathways and processes were revealed between PD and DS, which can serve as a theoretical basis for future research.

Toward Precise Nutrient Value of Feed in Growing Pigs: Effect of Meal Size, Frequency and Dietary Fibre on Nutrient Utilisation

Simple Summary

Feed costs are the most important in swine production. Precise determination of nutritional values of pig diets can help reducing feed costs by reducing security margins for nutrients and therefore provide a more sustainable swine production. In commercial farms, pigs have free access to feed and eat with no limitation according to their natural behaviour. In contrast, during digestibility trials, pigs are restricted in their daily intake of feed, which is distributed in a limited number of meals. The number of meals per day and the amount of feed consumed daily can affect the digestibility of the nutrients, the transit time and the metabolism. To reduce feed costs, by-products are frequently added to diets. Most by-products are rich in dietary fibre, which are known to have negative effects on digestibility. Enzymes can be supplemented in the diet to counteract the negative aspects of dietary fibre, but their efficiency can vary depending on the number of meals per day and the amount of feed consumed daily.

Abstract

Nutritional values of ingredients have been and still are the subject of many studies to reduce security margins of nutrients when formulating diets to reduce feed cost. In most studies, pigs are fed a limited amount of feed in a limited number of meals that do not represent how pigs are fed in commercial farm conditions. With free access to feed, pigs follow their intrinsic feeding behaviour. Feed intake is regulated by satiety and satiation signals. Reducing the feed intake level or feeding frequency can affect digestibility and transit time and induce metabolic changes. To reduce feed costs, alternative ingredients that are frequently rich in dietary fibre are added to diets. Fibre acts on the digestion process and transit time by decreasing energy density and causing viscosity. Various analyses of fibre can be realised, and the measured fibre fraction can vary. Exogenous enzymes can be added to counteract the effect of fibre, but digestive tract conditions, influenced by meal size and frequency, can affect the efficiency of supplemented enzymes. In conclusion, the frequency and size of the meals can affect the digestibility of nutrients by modulating gastrointestinal tract conditions (pH and transit time), metabolites (glucose and short-chain fatty acids) and hormones (glucagon-like peptide 1 and peptide tyrosine tyrosine).

Specific Binding of Leptin to Red Blood Cells Delivers a Pancreatic Hormone and Stimulates ATP Release

Since its discovery in 1994, leptin continues to have new potential physiological roles uncovered, including a role in the regulation of blood flow. Leptin's role in regulating blood flow is not completely understood. Red blood cell (RBC)-derived ATP is a recognized stimulus of blood flow, and multiple studies suggest that C-peptide, a hormone secreted in equimolar amounts with insulin from the pancreatic β-cells, can stimulate that release when delivered by albumin and in combination with Zn²⁺. Here, we report leptin delivers C-peptide and Zn²⁺ to RBCs in a saturable and specific manner. We labeled leptin with technetium-99 m (^99mTc) to perform binding studies while using albumin to block the specific binding of ^99mTc-leptin in the presence or absence of C-peptide. Our results suggest that leptin has a saturable and specific binding site on the RBC ((K_d = 1.79 ± 0.46) × 10^-7 M) that is statistically equal to the binding affinity in the presence of 20 nM C-peptide ((K_d = 2.05 ± 0.20) × 10^-7 M). While the binding affinity between leptin and the RBC did not change with C-peptide, the moles of bound leptin did increase with C-peptide, suggesting a separate binding site on the cell for a leptin/C-peptide complex. The RBC-derived ATP increased in the presence of a leptin/C-peptide/Zn²⁺ addition, in a concentration-dependent manner. Control RBCs ATP release increased (71 ± 5.6%) in the presence of C-peptide and Zn²⁺, which increased further to (94 ± 5.6%) in the presence of Zn²⁺, C-peptide, and leptin.

Effect of dietary intervention, with or without co-interventions, on inflammatory markers in patients with nonalcoholic fatty liver disease: a systematic literature review

CONTEXT

Nonalcoholic fatty liver disease (NAFLD) represents a spectrum of liver disorders, ranging from simple steatosis to nonalcoholic steatohepatitis (NASH), with inflammation acting as a key driver in its pathogenesis and progression. Diet has the potential to mediate the release of inflammatory markers; however, little is known about the effects of various diets.

OBJECTIVE

This systematic review aimed to evaluate the effect of dietary interventions on cytokines and adipokines in patients with NAFLD.

DATA SOURCES

The electronic databases MEDLINE, EMBASE, CINAHL, and Cochrane Library were searched for clinical trials investigating dietary interventions, with or without supplementation, on cytokines and adipokines in NAFLD patients.

DATA EXTRACTION

Basic characteristics of populations, dietary intervention protocol, cytokines, and adipokines were extracted for each study. Quality of evidence was assessed using the American Dietetic Association criteria.

DATA ANALYSIS

Nineteen studies with a total of 874 participants were included. The most frequently reported inflammatory outcomes were C-reactive protein (CRP), tumor necrosis factor alpha (TNF-α), interleukin 6 (IL-6), adiponectin, and leptin. Hypocaloric, isocaloric, or low-fat diets significantly (P < 0.05) lowered levels of CRP, TNF-α, and adiponectin. The addition of nutraceutical or pharmacological supplementation to dietary interventions appeared to elicit additional benefits for all of the most frequently reported inflammatory markers.

CONCLUSIONS

Hypo- or isocaloric diets alone, or with co-interventions that included a nutraceutical or pharmacological supplementation, appear to improve the inflammatory profile in patients with NAFLD. Thus, anti-inflammatory diets may have the potential to improve underlying chronic inflammation that underpins the pathophysiological mechanisms of NAFLD. In the absence of any known liver-sensitive markers, the use of cytokines and adipokines as a surrogate marker of liver disease should be further investigated in well-controlled trials.

New Actors Driving the Epithelial-Mesenchymal Transition in Cancer: The Role of Leptin

Leptin is a hormone secreted mainly by adipocytes; physiologically, it participates in the control of appetite and energy expenditure. However, it has also been linked to tumor progression in different epithelial cancers. In this review, we describe the effect of leptin on epithelial-mesenchymal transition (EMT) markers in different study models, including in vitro, in vivo, and patient studies and in various types of cancer, including breast, prostate, lung, and ovarian cancer. The different studies report that leptin promotes the expression of mesenchymal markers and a decrease in epithelial markers, in addition to promoting EMT-related processes such as cell migration and invasion and poor prognosis in patients with cancer. Finally, we report that leptin has the greatest biological relevance in EMT and tumor progression in breast, lung, prostate, esophageal, and ovarian cancer. This relationship could be due to the key role played by the enriched tumor microenvironment in adipose tissue. Together, these findings demonstrate that leptin is a key biomolecule that drives EMT and metastasis in cancer.

Association of Low Leptin with Poor 3-Month Prognosis in Ischemic Stroke Patients with Type 2 Diabetes

Background

Leptin, an adipokine, has effects on the cardiovascular system with both protective and harmful role. This study aimed to assess the relationship between leptin and 3-month prognosis in ischemic stroke patients with type 2 diabetes.

Patients and Methods

As a prospective single-center observational study, we collected consecutive first-ever acute ischemia stroke with type 2 diabetes mellitus from February 2019 to February 2020. Serum samples were obtained at admission, and leptin serum levels were tested by the ELISA method. Logistic regression models were used to assess leptin's prognostic value to predict the functional outcome and mortality within three months.

Results

Finally, two hundred and eleven patients were included, and the mean leptin serum level was 16.8 (SD. 6.9) ng/mL. At admission, 53.6% of those included patients (N=113) were defined as severe stroke (NIH Stroke Scale [NIHSS]>5). In multivariable models adjusted for other factors, leptin levels<11.6ng/mL (lowest quartile, Q1) related to severe stroke and the risk increased 175% (odds ratios [OR] =2.75; 95% confidence interval [CI]=2.13-3.38; P=0.002). Serum leptin levels on admission in patients with poor outcomes and nonsurvivors were significantly reduced (P<0.001 and P<0.001). Leptin levels <11.6ng/mL (lowest quartile, Q1) related to a higher risk of poor functional impairment (OR=5.13; 95% CI =3.25-6.86; P<0.001) and mortality (OR=3.19; 95% CI =2.03-4.25; P<0.001).

Conclusion

The data shows that leptin serum level is a useful prognostic biomarker in ischemic stroke patients with type 2 diabetes, and this relationship is negative.

Correlations between circulating leptin concentrations and growth performance, carcass traits, and meat quality indexes in finishing Simmental × Luxi bulls fed high-concentrate diets

Circulating leptin concentrations could potentially be used as a predictor of production traits in cattle. This study aimed to clarify the correlations between circulating leptin concentrations and growth performance, carcass traits, and meat quality indexes in finishing bulls fed high-concentrate diets (concentrate-to-forage ratio 70:30). Fifty-seven Simmental × Luxi F1 crossbred bulls were used for 112-day finishing experiment. Circulating leptin concentrations and relevant indexes of growth performance, and carcass traits and meat quality were measured during or after finishing trail. The results indicated that the leptin concentrations tended to be negatively correlated with dry matter intake (DMI) (r = -.233, p = .081), and were positively correlated with 12th-rib fat thickness (r = .330, p = .012), marbling score (r = .336, p = .011), and intramuscular fat content (r = .368, p = .021). Moreover, the leptin concentrations were negatively correlated with cholesterol content (r = -.339, p = .037) and were not correlated with sensory indexes including tenderness, juiciness, and like flavor (p > .05). In conclusion, circulating leptin concentrations may potentially be used as a predictor of carcass traits related to content of fat and beef quality traits related to content of cholesterol in finishing bulls fed high-concentrate diets.

Circulating leptin levels in patients with myalgic encephalomyelitis, chronic fatigue syndrome or fibromyalgia: a systematic review protocol

OBJECTIVE

The objective of the review is to evaluate circulating levels of leptin in people diagnosed with myalgic encephalomyelitis chronic fatigue syndrome or fibromyalgia syndrome and to investigate the differences compared with healthy controls.

INTRODUCTION

Myalgic encephalomyelitis chronic fatigue syndrome is a condition that has major symptoms, including self-reported fatigue, post-exertional malaise, and unexplained pain across the body. The widespread pain is measured in a systematic way and is often referred to as fibromyalgia. The two disorders have many similarities, but their association with leptin has indicated that leptin may affect the role of pro-inflammatory cytokines and symptom severity.

INCLUSION CRITERIA

This review will consider observational studies of varying study designs including prospective and retrospective cohort studies, case-control studies, time-series, and analytical cross-sectional studies that include both cases and healthy comparators. Cases will include a diagnosis of myalgic encephalomyelitis, chronic fatigue syndrome, and/or fibromyalgia. Controls are people without this diagnosis, usually healthy participants. Only studies published in English will be included due to limited resources for translation.

METHODS

This protocol will be reported based on the Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) checklist and will follow the JBI methodology for systematic reviews of etiology and risk. A comprehensive search strategy will include PubMed, Embase, Scopus, Science Direct, and PsycINFO. Two reviewers will screen, critically appraise eligible articles, and extract data using a standardized data extraction tool informed by JBI SUMARI. The authors will complete a quantitative analysis that synthesizes findings across studies using pooled effect sizes and confidence intervals of the measures provided.

SYSTEMATIC REVIEW REGISTRATION NUMBER

PROSPERO CRD42020169903.

Potential Cardiovascular and Metabolic Beneficial Effects of ω-3 PUFA in Male Obesity Secondary Hypogonadism Syndrome

Long-chain ω-3 polyunsaturated fatty acids (PUFAs) are fundamental biocomponents of lipids and cell membranes. They are involved in the maintenance of cellular homeostasis and they are able to exert anti-inflammatory and cardioprotective actions. Thanks to their potential beneficial effects on the cardiovascular system, metabolic axis and body composition, we have examined their action in subjects affected by male obesity secondary hypogonadism (MOSH) syndrome. MOSH syndrome is characterized by the presence of obesity associated with the alteration of sexual and metabolic functions. Therefore, this review article aims to analyze scientific literature regarding the possible benefits of ω-3 PUFA administration in subjects affected by MOSH syndrome. We conclude that there are strong evidences supporting ω-3 PUFA administration and/or supplementation for the treatment and management of MOSH patients.

Association of leptin mRNA expression with meat quality trait in Tianfu black rabbits

Leptin is a hormone synthesized and secreted primarily in adipocyte which can help to regulate energy balance. In this experiment, three tissue samples of Tianfu black rabbits at four growing periods were selected. The expression levels of leptin gene in different tissues were detected by real-time fluorescence quantitative PCR. The correlation analysis showed that the correlation coefficient between the expression levels of leptin gene in perirenal fat and intramuscular fat content in 84-day-old male rabbits was 0.73 (p < 0.05); the correlation coefficients between the expression levels of leptin gene in left biceps femoris and intramuscular fat and 24-hour pH in 84-day-old male rabbits were 0.95 (p < 0.01) and 0.85 (p < 0.05), respectively. Besides, the correlation coefficient between the expression levels of leptin gene in male left biceps femoris and cooked meat rate was 0.83 (p < 0.05). According to the analysis results, we inferred the expression levels of leptin gene in Tianfu black rabbits can influence meat quality and the meat quality of high expression levels of leptin gene in Tianfu black rabbits is better. These results revealed the leptin gene may be one of the important candidate genes for meat quality traits of molecular markers.

Changes in Serum Leptin Level After Multilevel Surgery in Patients with Obstructive Sleep Apnea

OBJECTIVE

Leptin hormone plays an important role in metabolic control and is elevated in obstructive sleep apnea (OSA). The aim of this study was to assess the hypothesis that surgical treatment will reduce leptin levels in OSA patients.

STUDY DESIGN

Prospective study.

SUBJECTS AND METHODS

Twenty-three patients with multilevel OSA underwent modified genioglossus muscle advancement with anterolateral advancement pharyngoplasty between April 2018 and September 2019. Serum leptin level was measured preoperatively and 3 months postoperatively for all patients and 18 control subjects. All patients were evaluated before and 3 months after surgery by history taking, clinical examination, polysomnography, cephalometry, and Epworth Sleepiness Scale.

RESULTS

Preoperatively, patients with OSA had a higher Leptin level (18.46 ± 4.73 ng/mL) than did control subjects (7.07 ± 1.26 ng/mL) (P < .001). Surgery resulted in a significant reduction in the level of leptin from 18.46 ± 4.73 ng/mL to 8.03 ± 2.22 ng/mL (P < .001). Reductions in leptin level was correlated with changes in apnea hypopnea index (AHI) (r = 0.61, P = .002) and minimum oxygen saturation (SaO2) (r = -0.54, P = .008).

CONCLUSION

Effective multilevel surgery in the form of modified genioglossus muscle advancement with anterolateral advancement pharyngoplasty could significantly reduce leptin level in OSA patients and this reduction is correlated with the degree of OSA improvement in term of AHI and SaO2.

LEVEL OF EVIDENCE

4 Laryngoscope, 131:E665-E670, 2021.

Prevalence of obesity and overweight in Iranian students: a systematic review and meta-analysis

Background Obesity and overweight are among the most common and serious health issues in many countries, leading to numerous medical consequences such as heart disease, hypertension, fatty liver etc. This review article addressed the prevalence of obesity and overweight in Iranian students by using meta-analysis. Methods A number of domestic and international databases were searched, including IranMedex, Magiran, SID, Scopus, PubMed, IranDoc, Web of Science and Google Scholar. Eligible publications were 160 articles that addressed the prevalence of obesity or overweight. Data were combined using random effects model. Heterogeneity of the studies was examined by Q statistics and the I2 index. Data were analyzed using STATA version 11.1. Results In the 160 reviewed studies, a total of 481,070 individuals (6-20 years) were included. The prevalence of obesity among Iranian students based on body mass index (BMI) was 11% (95% confidence interval [CI]: 10%-12%) (in girls 8% [95% CI: 7%-10%] and in boys 11% [95% CI: 10%-13%]). The prevalence of overweight in students based on BMI was 12% (95% CI: 12%-13%) (in girls 13% [95% CI: 11%-14%] and in boys 11% [95% CI: 18%-30%]). The rate of obesity was 13% (95% CI: 11%-16%) in elementary school students, 10% (95% CI: 7%-14%) in secondary school students and 7% (95% CI: 6%-9%) in high school students. Conclusions The prevalence rate of overweight was more than that of obesity with a 1% difference. The prevalence of obesity was higher in boys, while the prevalence of overweight was higher in girls. The prevalence of obesity was higher in primary school students than in secondary school students. This prevalence was higher in secondary school students than in high school students.

Does cord blood leptin level mediate the association between neonatal body size and postnatal growth? Results from the EDEN mother-child cohort study

Background: Leptin is potentially involved in the correction of early postnatal growth of infants having deviated from their genetic trajectory in utero.Aim: To analyse the potential mediating role of cord blood leptin level in the association between neonatal anthropometry and early postnatal growth in the mother-child EDEN cohort.Subjects and methods: We included term newborns with information on leptin, birth weight and length, and weight and length SD-score changes over the first 2 months. The Baron and Kenny method was used to quantify the mediation contribution of leptin in the association between neonatal anthropometry and postnatal growth, considering several confounders. Analyses were stratified to consider sexual dimorphism.Results: A 1 SD higher birth weight was associated with a lower 2-months weight variation of 0.27 (0.18; 0.36) SD and a 0.16 (0.06; 0.26) SD, in boys and girls, respectively. Leptin explained 20% and 25% of these associations, respectively. Leptin did not mediate the association between birth length and birth-to-2 months length variation.Conclusion: Our results suggest that cord blood leptin may not be involved in the negative association between birth length and postnatal length growth but may play a modest mediating role in early postnatal catch-up or catch-down in weight.

Mild Hypothermia Attenuates Hepatic Ischemia-Reperfusion Injury through Regulating the JAK2/STAT3-CPT1a-Dependent Fatty Acid β-Oxidation

Hepatic ischemia–reperfusion (IR) injury is a clinical issue that can result in poor outcome and lacks effective therapies at present. Mild hypothermia (32–35°C) is a physiotherapy that has been reported to significantly alleviate IR injury, while its protective effects are attributed to multiple mechanisms, one of which may be the regulation of fatty acid β-oxidation (FAO). The aim of the present study was to investigate the role and underlying mechanisms of FAO in the protective effects of mild hypothermia. We used male mice to establish the experimental models as previously described. In brief, before exposure to in situ ischemia for 1 h and reperfusion for 6 h, mice received pretreatment with mild hypothermia for 2 h and etomoxir (inhibitor of FAO) or leptin (activator of FAO) for 1 h, respectively. Then, tissue and blood samples were collected to evaluate the liver injury, oxidative stress, and changes in hepatic FAO. We found that mild hypothermia significantly reduced the hepatic enzyme levels and the score of hepatic pathological injury, hepatocyte apoptosis, oxidative stress, and mitochondrial injury. In addition, the expression of the rate-limiting enzyme (CPT1a) of hepatic FAO was downregulated almost twofold by IR, while this inhibition could be significantly reversed by mild hypothermia. Experiments with leptin and etomoxir confirmed that activation of FAO could also reduce the hepatic enzyme levels and the score of hepatic pathological injury, hepatocyte apoptosis, oxidative stress, and mitochondrial injury induced by IR, which had the similar effects to mild hypothermia, while inhibition of FAO had negative effects. Furthermore, mild hypothermia and leptin could promote the phosphorylation of JAK2/STAT3 and upregulate the ratio of BCL-2/BAX to suppress hepatocyte apoptosis. Thus, we concluded that FAO played an important role in hepatic IR injury and mild hypothermia attenuated hepatic IR injury mainly via the regulation of JAK2/STAT3-CPT1a-dependent FAO.

Up-regulation of bone morphogenetic protein and its signaling molecules following castration of bulls and their association with intramuscular fat content in Korean cattle

We evaluated whether castration affects bone morphogenetic protein 2 (BMP2) level and the expression of its signaling molecules in Korean cattle bulls. We also checked whether castration affects the expression of muscle fiber type and oxidative and glycolytic enzyme genes. Enzyme-linked immunosorbent assays revealed that steers had higher plasma BMP2 and leptin concentrations than bulls. Quantitative real-time PCR showed that steers had higher mRNA levels of the lysyl oxidase gene, a downstream target of the BMP signaling pathway, in the longissimus thoracis (LT) muscle. Steers had higher adipogenic peroxisome proliferator-activated receptor gamma and lipogenic fatty acid binding protein 4 mRNA levels in the LT than bulls. Steers had lower mRNA levels for several muscle fiber type 1 genes and fiber type 2A myosin heavy chain 2 gene than bulls. Steers had higher mRNA levels of the glycolytic enzyme phosphoglycerate kinase 1 gene than bulls. Transcript levels of oxidative enzyme genes did not differ between bulls and steers. Regression analysis revealed a positive association between plasma BMP2 levels and intramuscular fat (IMF) content in the steer group. These findings suggest that upregulation of the BMP signaling pathway in response to castration induces increased adipogenic gene expression, contributing to the increased IMF deposition observed in castrated animals.

Effects of OSA Surgery on Leptin and Metabolic Profiles

OBJECTIVES

This study is designed to investigate the effects of obstructive sleep apnea/hypopnea syndrome (OSA) surgery on serum leptin levels and metabolic disturbances, both of which contribute to the risk of cardiovascular diseases.

STUDY DESIGN

Case series with planned data collection.

SETTING

Tertiary referral medical center.

SUBJECTS AND METHODS

A retrospective chart review of 101 consecutive patients with OSA who refused or failed conservative therapy and who then underwent upper airway surgery for OSA treatment was conducted. The personal medical history, anthropometric measurements, subjective symptoms, and objective polysomnographic parameters and fasting morning blood samples for leptin and metabolic biomarkers measurements were collected preoperatively and at a minimum of 3 months postoperatively.

RESULTS

Eighty patients with OSA (69 men and 11 women; mean [SD] age of 42.2 [10.2] years) with complete data were included in the final analysis. At least 3 months after surgery, serum leptin, low-density lipoprotein cholesterol (LDL-C), and triglyceride levels and the mean systolic blood pressure (SBP) (night and morning) significantly decreased. According to the classical definition of surgical success, 40 subjects had successful surgery and were categorized as surgical responders, and the other 40 patients who failed surgery were categorized as surgical nonresponders. Significant reductions in serum leptin, total cholesterol, LDL-C, and triglyceride levels and improvement of mean SBP (morning) occurred in surgical responders but not in nonresponders.

CONCLUSIONS

Effective OSA surgery improves serum leptin, lipid profiles, and SBP. Further studies are needed to investigate the role of serial measurements of these biomarkers in monitoring surgical outcome of OSA treatment.

Clinical Trials Required to Assess Potential Benefits and Side Effects of Treatment of Patients With Anorexia Nervosa With Recombinant Human Leptin

The core phenotype of anorexia nervosa (AN) comprises the age and stage dependent intertwining of both its primary and secondary (i.e., starvation induced) somatic and mental symptoms. Hypoleptinemia acts as a key trigger for the adaptation to starvation by affecting diverse brain regions including the reward system and by induction of alterations of the hypothalamus-pituitary-“target-organ” axes, e.g., resulting in amenorrhea as a characteristic symptom of AN. Particularly, the rat model activity-based anorexia (ABA) convincingly demonstrates the pivotal role of hypoleptinemia in the development of starvation-induced hyperactivity. STAT3 signaling in dopaminergic neurons in the ventral tegmental area (VTA) plays a crucial role in the transmission of the leptin signal in ABA. In patients with AN, an inverted U-shaped relationship has been observed between their serum leptin levels and physical activity. Albeit obese and therewith of a very different phenotype, humans diagnosed with rare congenital leptin deficiency have starvation like symptoms including hypothalamic amenorrhea in females. Over the past 20 years, such patients have been successfully treated with recombinant human (rh) leptin (metreleptin) within a compassionate use program. The extreme hunger of these patients subsides within hours upon initiation of treatment; substantial weight loss and menarche in females ensue after medium term treatment. In contrast, metreleptin had little effect in patients with multifactorial obesity. Small clinical trials have been conducted for hypothalamic amenorrhea and to increase bone mineral density, in which metreleptin proved beneficial. Up to now, metreleptin has not yet been used to treat patients with AN. Metreleptin has been approved by the FDA under strict regulations solely for the treatment of generalized lipodystrophy. The recent approval by the EMA may offer, for the first time, the possibility to treat extremely hyperactive patients with AN off-label. Furthermore, a potential dissection of hypoleptinemia-induced AN symptoms from the primary cognitions and behaviors of these patients could ensue. Accordingly, the aim of this article is to review the current state of the art of leptin in relation to AN to provide the theoretical basis for the initiation of clinical trials for treatment of this eating disorder.

Gender-specific change in leptin concentrations during long-term CPAP therapy

Purpose

Nasal continuous positive airway pressure (CPAP) alleviates sleepiness in patients with obstructive sleep apnoea syndrome (OSAS), but part of OSAS patients keep gaining weight. Leptin and insulin-like growth factor-1 (IGF-1) interact with energy balance, and CPAP therapy has been suggested to influence these endocrine factors. We hypothesised that leptin would decrease during long-term CPAP therapy, and weight gain would associate with OSAS severity, lower CPAP adherence, lower IGF-1, and leptin concentrations.

Methods

Consecutive patients (n = 223) referred to sleep study with suspected OSAS were enrolled. Patients underwent cardiorespiratory polygraphy at baseline. Questionnaires were completed, and blood samples were drawn both at baseline and after 3 years. A total of 149 (67%; M 65, F 84) patients completed the follow-up. Plasma samples were available from 114 patients, 109 of which with CPAP adherence data (49 CPAP users, 60 non-users).

Results

At baseline, the CPAP users were more obese and had more severe OSAS than the non-users. Leptin concentrations did not differ. After follow-up, leptin concentrations were higher in CPAP users (30.2 ng/ml vs. 16.8 ng/ml; p = 0.001). In regression analysis, increase in leptin concentrations was independent of age, baseline body mass index (BMI), or the change in BMI. Leptin concentrations increased among females (− 8.9 vs. 12.7 ng/ml; p < 0.001); whereas in men, CPAP did not have an effect, if not opposed the natural decrease in leptin observed in men not using CPAP. Change in IGF-1 levels did not differ.

Conclusions

Our results suggest increase in leptin concentrations during long-term CPAP therapy among females.

Electronic supplementary material

The online version of this article (10.1007/s11325-019-01846-y) contains supplementary material, which is available to authorized users.

A new approach to study the sex differences in adipose tissue

Obesity is one of the most invaliding and preventable diseases in the United States. Growing evidence suggests that there are sex differences in obesity in human and experimental animals. However, the specific mechanisms of this disease are unknown. Consequently, there is any particular treatment according to the sex/gender at this time. During the last decade, we observe a rise in the study of adipocyte and the possible mechanisms involved in the different roles of the fat. Furthermore, the effect of sex steroids on the adipocyte is one of the fields that need elucidation. Supporting evidence suggests that sex steroids play an essential role not only in the fat distribution, but also, in its metabolism, proliferation, and function. Thus, using in vitro and in vivo studies will contribute to our fight against this critical health public problem encompassing both sexes. In the present review, we discuss some of the recent advances in the adipocytes and the effect of the sex steroids on the adipose tissue. Also, we propose a new alternative to study the role of sex steroids on adipocyte biology through human adipose-derived stem cells.

Treating Obstructive Sleep Apnea and Chronic Intermittent Hypoxia Improves the Severity of Nonalcoholic Fatty Liver Disease in Children

OBJECTIVE

To determine the effects of treating obstructive sleep apnea/nocturnal hypoxia on pediatric nonalcoholic fatty liver disease (NAFLD) severity and oxidative stress.

STUDY DESIGN

Biopsy proven participants (n = 9) with NAFLD and obstructive sleep apnea/hypoxia were studied before and after treatment with continuous positive airway pressure (CPAP) for sleep disordered breathing, including laboratory testing and markers of oxidative stress, urine F(2)-isoprostanes.

RESULTS

Adolescents (age 11.5 ± 1.2 years; body mass index, 29.5 ± 3.8 kg/m²) with significant NAFLD (mean histologic necroinflammation grade, 2.3 ± 0.9; fibrosis stage, 1.4 ± 1.3; NAFLD Activity Score summary, 4.8 ± 1.6) had obstructive sleep apnea/hypoxia by polysomnography. At baseline, they had severe obstructive sleep apnea/hypoxia, elevated aminotransferases, the metabolic syndrome, and significant oxidative stress (high F(2)-isoprostanes). Obstructive sleep apnea/hypoxia was treated with home CPAP for a mean 89 ± 62 days. Although body mass index increased, obstructive sleep apnea/hypoxia severity improved on CPAP and was accompanied by reduced alanine aminotransferase, metabolic syndrome markers, and F(2)-isoprostanes.

CONCLUSIONS

This study provides strong evidence that treatment of obstructive sleep apnea/nocturnal hypoxia with CPAP in children with NAFLD may reverse parameters of liver injury and reduce oxidative stress. These data also suggest CPAP as a new therapy to prevent progression of NAFLD in those children with obesity found to have obstructive sleep apnea/nocturnal hypoxia.

Association between circulating leptin levels and multiple sclerosis: a systematic review and meta-analysis

Aim

Leptin, synthesised by adipocytes, has been identified as a hormone that can influence inflammatory activity. Several studies have investigated leptin levels in patients with multiple sclerosis (MS), but the results are not consistent. This study aims to derive a more precise evaluation on the relationship between circulating leptin levels and MS.

Design

A comprehensive literature searched up to July 2017 was conducted to evaluate the association of circulating leptin levels and MS. The random-effect model was applied to calculate pooled standardised mean difference (SMD) and its 95% CI.

Main outcome measures

Circulating leptin levels of patients with MS and healthy controls.

Results

Of 2155 studies identified, 33 met eligibility criteria and 9 studies with 645 patients with MS and 586 controls were finally included in the meta-analysis. Meta-analysis revealed that, compared with the healthy control group, the MS group had significantly higher plasma/serum leptin levels, with the SMD of 0.70% and 95% CI (0.24 to 1.15). Subgroup analyses suggested that the leptin levels of patients with MS were associated with region, age, study sample size, measurement type, gender and blood sample type.

Conclusion

Overall, our study suggests that patients with MS have a significantly higher leptin level than in healthy controls. Further mechanism studies and longitudinal large cohort studies are still needed to further reveal the role of leptin in the pathogenesis of MS.

Serum Levels of Leptin in Multiple Myeloma Patients and Its Relation to Angiogenic and Inflammatory Cytokines

Background

Leptin, apart from the regulation of food intake, has been implicated in hematopoiesis, the immune response and angiogenesis. Leptin has been found to be decreased in various hematological malignancies. In the present study leptin was measured in multiple myeloma (MM) patients before and after treatment and correlated with other angiogenic molecules and markers of disease activity.

Methods

Serum leptin, vascular endothelial growth factor (VEGF), basic fibroblast growth factor (b-FGF), interleukin-1 beta (IL-1β), beta 2 microglobulin (β2M) and C-reactive protein (CRP) were measured in 62 newly diagnosed MM patients, 22 of whom obtaining disease stabilization after treatment. The same parameters were measured in 20 healthy controls. Disease stage was defined according to the Durie-Salmon criteria.

Results

Leptin, VEGF, b-FGF, IL-1β, and β2M were significantly higher in newly diagnosed MM patients than in controls (p<0.05). VEGF, b-FGF, IL-1β, β2M, CRP but not leptin increased with advancing stage of disease (p<0.01). All parameters decreased significantly following treatment (p<0.001). Although IL-1β correlated positively with VEGF, β2M, b-FGF and CRP, leptin did not correlate with any of the measured parameters.

Conclusion

Leptin serum levels do not reflect disease severity in MM. However, there seems to be a decrease in leptin following treatment, which may be associated with an alteration in the metabolic state or the chemokine milieu.

The serum leptin level in non-obese patients with obstructive sleep apnea

OBJECTIVE

This study aimed to determine the association between the severity of obstructive sleep apnea (OSA) and the serum leptin level in non-obese OSA patients.

METHODS

This prospective case-control study included non-obese OSA patients that presented with sleep-related disturbances and underwent polysomnography (PSG) between April 2015 and June 2016. The serum leptin level was measured and its relationship to PSG parameters was investigated.

RESULTS

The study included 73 OSA patients (20 female and 53 male) with a mean age of 41.1±11.5 years and mean body-mass index (BMI) of 26.4±2.7kgm^-2. The serum leptin level in 44 patients with moderate/severe OSA (AHI ≥15) was 3.4±2.6ngmL^-1, versus 4.5±3.8ngmL^-1 in 29 patients with snoring/mild OSA (AHI <15) (P=0.20). There were not any correlations between any of the PSG parameters and the serum leptin level, but there was a significant correlation between the leptin level and BMI (r=0.345, P<0.01).

CONCLUSION

The serum leptin level does not differ significantly between non-obese OSA patients with moderate/severe and snoring/mild OSA. Obesity is the primary factor associated with the serum leptin level.

Reactive leptin resistance and the profile of platelet activation in acute ischaemic stroke patients

Summary

Leptin is an adipokine that in vitro enhances agonist-induced platelet aggregation and adipokine expression. Hyperleptinaemia represents a risk factor for cardiovascular disease. We conducted a prospective evaluation of the potential link between blood platelet activation and plasma leptin levels in post-stroke patients. Using five-colour flow cyto-metry, the platelet surface expression of CD40L, CD62P, the subpopulations of monocyte-platelet aggregates and platelet-derived microparticles (PMPs) as well as the plasma leptin, soluble leptin receptor (sOb-R), leptin/sOb-R ratio, the plasma adiponectin, and leptin/adiponectin ratio were assessed in 98 stroke patients on the first (V0), 10th (V1) and 90th (V2) day after stroke and once in 78 age-, gender- and vascular risk factor-matched disease controls. We demonstrated that at V0 leptin resistance, defined as leptin/sOb-R ratio, was higher than in the controls [1.1 (0.5–1.8 vs. 0.5 (0.2–1.1); p=0.02]. After adjustment according to the factors which influence platelet activation, we confirmed the relationship between percentage of circulating PMPs and plasma leptin level (B=0.18; p=0.02) or the leptin/sOb-R ratio (B=0.23; p=0.02) in normal-weight subjects in the acute phase of stroke. No correlation could be demonstrated between the adipokine parameters and the percentage of monocyte-platelet aggregates or expression of platelet pro-inflammatory glycoproteins. In conclusion, formation of PMPs on the first day following an ischaemic stroke shows a positive correlation with leptin levels and with resistance to leptin. Leptin level does not seem to affect the expression of platelet surface proinflammatory glycoproteins.

Serum and exhaled breath condensate leptin levels in asthmatic and obesity children: a pilot study

BACKGROUND

Recent studies have highlighted the possible involvement of leptin in inflammation. The leptin receptor is also expressed by alveolar macrophages, T lymphocytes and bronchial epitelial cells, suggesting a possible role in the cascade of airway inflammation.

OBJECTIVES

The aim of the study was to evaluate the levels of leptin in exhaled breath condensate (EBC) from asthmatic, normal- and overweight children, in relationship with airway inflammation.

METHODS

15 asthmatic non-obese children, 15 healthy non-asthmatic non-obese children, 11 obese children with asthma (OA) and 20 obese children without asthma (ONA) were enrolled. Body impedance of body weight, EBC collection, FeNO, spirometry and a blood sampling for serum leptin were assessed.

RESULTS

Leptin EBC levels were significantly higher (3.9 ng ml^-1 ± 1.3) in overweight children than those obese with asthma (3.6 ng ml^-1 ± 1.6; p = 0.97), non-owerweight asthmatics (2.2 ng ml^-1 ± 1.2; p < 0.0001) and in healthy children (0.9 ng ml^-1 ± 0.6; p < 0.001). Leptin EBC levels in asthmatic children were significantly higher than in healthy children (p = 0.05). Leptin serum levels were significantly higher in the overweight children compared with the asthmatics (12.7 ng ml^-1 ± 13.2; p < 0.001) and the healthy group (11.1 ng ml^-1 ± 11.2; p < 0.001). We observed a significant correlation between EBC-leptin levels and the serum-leptin levels (p = 0.001). No correlations were found between EBC-leptin levels, FeNO and lung function.

CONCLUSIONS

This study shows that leptin is measurable in EBC in children and that EBC-leptin levels are significantly higher in the obese subjects and in asthmatic ones compared with healthy subjects. Leptin may therefore represent a non-invasive marker of non-specific airway inflammation in children.

Alamandine reduces leptin expression through the c-Src/p38 MAP kinase pathway in adipose tissue

Objective

Obesity is associated with an increased risk of diabetes mellitus, hypertension, and renal dysfunction. Angiotensin 1–7 and alamandine are heptameric renin angiotensin system peptide hormones. Further, alamandine levels increase with renal dysfunction. In the cardiovascular system, angiotensin 1–7 and alamandine produce similar improvements and counterbalance angiotensin II in regulating vascular function. We aimed to determine whether the effect of alamandine on leptin expression and secretion in adipocytes was similar to that of angiotensin 1–7.

Approach and results

We studied isolated peri-renal visceral adipose tissue and peri-renal isolated visceral adipocytes from male Wistar rats. Angiotensin II from 0.01 to 10nM had no effect on leptin expression. Angiotensin 1–7 (1 nM) increased leptin secretion and expression, whereas alamandine (1 nM) decreased leptin secretion and expression in adipose tissue and isolated adipocytes and reduced blood leptin levels in vivo. These effects were mediated by Gq, c-Src, p38 mitogen-activated protein, and IκB activation. Additionally, alamandine induced nitric oxide expression via inducible nitric oxidase synthase and plasminogen activator inhibitor 1 expression in adipose tissue and isolated adipocytes.

Conclusions

Angiotensin 1–7 and alamandine produced opposing effects on leptin expression and secretion in adipose tissue. This result suggests that the action of Mas (angiotensin 1–7 receptor) and Mas-related G-protein coupled receptor D in adipocytes exhibited opposing actions similar to angiotensin II type 1 and type 2 receptors.

Leptin induces osteoblast differentiation of human valvular interstitial cells via the Akt and ERK pathways

AIMS

Calcific aortic valve disease (CAVD) affects 2-6% of the population over 65 years, and age, gender, smoking, overweight, dyslipidemia, diabetes contribute to the development of this disease. CAVD results, in part, from the osteoblast differentiation of human valvular interstitial cells (VICs). This study aims to elucidate the effects of leptin on osteoblast phenotype of VICs and the signalling pathways involved.

METHODS

Patients who underwent aortic valve replacement for CAVD (n = 43) were included in this study. Patients with coronary artery disease (CAD) without CAVD (n = 129) were used as controls.

RESULTS

Patients with CAVD had higher serum leptin concentrations than CAD patients (p = 0.002). Leptin was found in calcific aortic valves, with higher concentrations in calcified versus non-calcified zones (p = 0.01). Chronic leptin stimulation of human VICs enhanced alkaline phosphatase (ALP) activity and ALP, BMP-2 and RUNX2 expression and decreased osteopontin expression. Moreover, inhibiting Akt or ERK during leptin stimulation lowered the expression of osteoblast markers in VIC.

CONCLUSIONS

Taken together, these findings indicate that leptin plays a critical role in CAVD development by promoting osteoblast differentiation of human aortic VICs in an Akt- and ERK-dependent manner. This study highlights the role of leptin in CAVD development, and further studies are needed to determine whether reducing circulating leptin levels or blocking leptin actions on VICs is efficient to slow CAVD progression.

Do In Seung Gi‑Tang extract suppresses adipocyte differentiation in 3T3‑L1 cells

Blood stasis syndrome (BSS), additionally called Eohyul, is a basic pathological concept in Traditional Korean Medicine. Do In Seung Gi‑Tang (DISGT) is herbal medicine used for the treatment of BSS. It primarily treats metabolic diseases (MDs) including obesity, hypertension, diabetes mellitus and gynecological diseases, by promoting blood circulation. The present study aimed to investigate the anti‑adipogenesis effect of DISGT in 3T3‑L1 adipocytes using Oil Red O staining, and assessing levels of triglycerides (TGs) and leptin in adipocytes by ELISA and western blot analysis. The results demonstrated that DISGT treatment had inhibitory effects on fat droplet formation, TG accumulation, leptin production and cytokine content, during 3T3‑L1 adipocyte differentiation, without affecting cell viability. Additionally, DISGT treatment significantly suppressed the protein expression levels of peroxisome proliferator‑activated receptor γ and CAAT/enhancer binding protein α. These results provide evidence that DISGT has anti‑adipogenesis effects on preadipocytes and adipocytes by significantly blocking adipocyte differentiation and lipid accumulation, and suppressing adipogenic gene expression. Therefore, the present study demonstrated the potential of DISGT as a therapeutic agent for the treatment of MDs.

The Effect of apoM Polymorphism Associated with HDL Metabolism on Obese Korean Adults

BACKGROUND

Apolipoprotein M (apoM) is a recently identified apolipoprotein associated with high-density lipoprotein (HDL) in coronary artery disease (CAD), but the association between apoM polymorphism and obesity has not been reported.

AIM

To investigate the association between apoM polymorphism and obesity prevalence in 584 Korean adults.

METHODS

A total of 584 individuals aged between 30 and 80 years were recruited from Yonsei Medical Center in Seoul, Korea, and divided into obese (OB; body mass index, BMI ≥25) and nonobese (non-OB; BMI <25) groups. Anthropometric variables, lipid profiles, insulin-resistant profiles, reverse cholesterol transport (RCT) enzymes, HDL subfraction, and apoM polymorphism were determined.

RESULTS

In OB with T-855C polymorphism, TT genotype carriers significantly showed 6.2% higher diastolic blood pressure (DBP), 1.3% lower amount of HDL2b subfraction, and 19.7% higher lecithin-cholesterol acyltransferase (LCAT) mass than TC+CC carriers. OB subjects with the T allele of T-778C polymorphism significantly demonstrated 43% higher plasma insulin, 17.7% higher total cholesterol, 26.7% higher triglyceride, 40.7% higher leptin, 1.6% lower HDL2b, and 12.6% higher LCAT mass than those with the C allele. These results were reversed in non-OB with T-778C polymorphism regarding HDL subfractions and RCT enzymes.

CONCLUSION

apoM T-855C and T-778C polymorphisms were found to be associated with obesity by regulating HDL metabolism, and the T alleles of apoM T-778C were shown to be more strongly correlated.

Leptin receptor expression during the progression of endometrial carcinoma is correlated with estrogen and progesterone receptors

INTRODUCTION

The hormone leptin, which is produced in the adipose tissue, may influence tumorigenesis directly via its receptor (Ob-R). Thus, a role for Ob-R in endometrial carcinogenesis has been proposed. However, most studies neither included samples of the entire histological progression of endometrial carcinoma nor examined Ob-R jointly with the estrogen and progesterone receptors (ER and PR, respectively).

MATERIAL AND METHODS

To determine the fluctuations of Ob-R, ER, and PR during the histological progression of endometrial carcinoma, we assessed their expression via immunohistochemistry (IHC) in six histological types of endometrium (proliferative, secretory, nonatypical and atypical hyperplasia, and endometrioid and nonendometrioid endometrial carcinoma), in which we performed histopathological and digital scoring for the quantification of receptors.

RESULTS

We found that Ob-R expression was positively correlated with that of ER and PR (r = 1, p < 0.001; r = 0.943, p < 0.005, respectively), and there was a significant difference in Ob-R expression among proliferative normal endometrium, hyperplasias, and carcinomas, according to their relative digitally scored Ob-R expression (p < 0.001). In addition, we observed that Ob-R expression in the secretory endometrium was more similar to that of carcinomas than to its proliferative counterpart.

CONCLUSIONS

These results indicate that Ob-R expression fluctuates during endometrial carcinogenesis in correlation with ER and PR, suggesting that Ob-R expression in vivo is highly dependent on estrogen and progesterone activities in the endometrium and on its ER and PR status, as suggested previously by in vitro studies.

Relationships between Bone Turnover and Energy Metabolism

It is well established that diabetes can be detrimental to bone health, and its chronic complications have been associated with an increased risk of osteoporotic fracture. However, there is growing evidence that the skeleton plays a key role in a whole-organism approach to physiology. The hypothesis that bone may be involved in the regulation of physiological functions, such as insulin sensitivity and energy metabolism, has been suggested. Given the roles of insulin, adipokines, and osteocalcin in these pathways, the need for a more integrative conceptual approach to physiology is emphasized. Recent findings suggest that bone plays an important role in regulating intermediary metabolism, being possibly both a target of diabetic complications and a potential pathophysiologic factor in the disease itself. Understanding the relationships between bone turnover and glucose metabolism is important in order to develop treatments that might reestablish energy metabolism and bone health. This review describes new insights relating bone turnover and energy metabolism that have been reported in the literature.

Triglycerides Revisited to the Serial

This review discusses the role of triglycerides (TGs) in the normal cardiovascular system as well as in the development and clinical manifestation of cardiovascular diseases. Regulation of TGs at the enzymatic and genetic level, in addition to their possible relevance as preclinical and clinical biomarkers, is discussed, culminating with a description of available and emerging treatments. Due to the high complexity of the subject and the vast amount of material in the literature, the objective of this review was not to exhaust the subject, but rather to compile the information to facilitate and improve the understanding of those interested in this topic. The main publications on the topic were sought out, especially those from the last 5 years. The data in the literature still give reason to believe that there is room for doubt regarding the use of TG as disease biomarkers; however, there is increasing evidence for the role of hypertriglyceridemia on the atherosclerotic inflammatory process, cardiovascular outcomes, and mortality.