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Serum Leptin Levels (serum + leptin_level)

Distribution by Scientific Domains

Medical Sciences	97%

Distribution within Medical Sciences

Pediatrics	22%
General & Internal Medicine	11%
Gastroenterology & Hepatology	8%
Dermatology	5%
10 Other Subdomains	49%

Selected Abstracts

The Relationship Between Leptin Level and Oxidative Status Parameters in Hemodialysis Patients

ARTIFICIAL ORGANS, Issue 1 2009
Mehmet Horoz
Abstract Both serum leptin level and oxidative stress are increased in hemodialysis (HD) patients. In the present study, we aimed to investigate whether there is association between oxidative status and leptin level in HD patients. Thirty-five HD patients and 25 healthy controls were enrolled in the present study. Serum leptin level, total peroxide (TP) level, total antioxidant capacity (TAC), and oxidative stress index (OSI) were determined. Serum leptin level, TP level, and OSI were significantly higher in HD patients than controls (all P < 0.001) while TAC was lower (P < 0.001). In HD patients, serum leptin level was significantly correlated with TP level and OSI (r = 0.372, P < 0.001 and r = 0.409, P < 0.001, respectively). The correlation of serum leptin level with TP level and OSI remained statistically significant after adjusting for age, gender, and body-fat percentage (r = 0.446, P < 0.001 and r = 0.463, P < 0.001, respectively). Hyperleptinemia seems to be associated with increased oxidative stress in HD patients, and this association may provide better understanding about the disorders related to either elevated serum leptin levels and/or increased oxidative stress in HD patients. [source]

The neurobiology and genetics of eating and weight regulation

JOURNAL OF INTELLECTUAL DISABILITY RESEARCH, Issue 10 2008
J. Hebebrand
Over the past 15 years tremendous advances have been made in the elucidation of pathways relevant to eating behaviour and body weight regulation. It has become evident that these pathways are intricately interwoven with those underlying mood and anxiety regulation, motor activity, cognition, sleep, fertility and libido. In addition, advances have been made in determining genetic variation underlying inter-individual differences in body weight. To illustrate these novel findings we will focus on: 1) Monogenic and oligogenic obesity: The underlying genes were initially detected in animal models. Based on mutation screens of the human homologues functionally relevant mutations were detected in the genes coding for leptin, its receptors and the melanocortin-4 receptor (MC4R). The effect of such mutations is large. Leptin gene mutations lead to hyperphagia and subsequently obesity. Hyperphagia, albeit of a substantially reduced magnitude, has also been observed in obese children with mutations in the MC4R. 2) Polygenic obesity: The advent of genome wide association studies has led to the detection of single polygenes, among which FTO features prominently. Typically, a variant predisposing to obesity accounts for a body weight elevated by on average 200 to 1500 grams. Such polygenes act in concert to account for inter-individual differences in body weight. 3) Leptin has been shown to have profound implications for anorexia nervosa. Serum leptin levels in this eating disorders are annormaly low. The hypoleptinemia entails a down-regulation of the hypothalamic-pituitary-gonadal-axis, which underlies the amenorrhea characteristic of anorexia nervosa. Furthermore, the hypoleptinemia induces hyperactivity in a rat model of anorexia nervosa. In patients, leptin levels are inversely correlated with activity levels. [source]

Expression of leptin receptor in nasal polyps: Leptin as a mucosecretagogue,

THE LARYNGOSCOPE, Issue 5 2010
Si-Youn Song MD
Abstract Objectives/Hypothesis: Leptin is a pleiotropic hormone that regulates food intake and metabolic and endocrine functions. Serum leptin levels have been reported to be increased in patients with allergic rhinitis and nasal polyposis; however, the explanation for this is unclear. We aimed to demonstrate the differential expression of leptin receptors in normal human nasal mucosa and nasal polyps, and to elucidate the effects of leptin on mucin gene expression in human nasal polyp epithelial cells. Study Design: Case-control and in vitro study. Methods: Normal ethmoid sinus mucosa was obtained from 10 subjects and used as a control; nasal polyps were obtained from 10 patients. Leptin receptor expression was analyzed using reverse transcriptase-polymerase chain reaction (RT-PCR) and Western blot analysis. Leptin-induced expression of major respiratory mucins (MUC5AC and MUC5B) in the human nasal polyp epithelial cells was determined using RT-PCR and enzyme-linked immunosorbent assay. Results: The leptin receptor expression was stronger in the nasal polyps than in the normal nasal mucosa. In human nasal polyp epithelial cells, leptin increased the expression of MUC5AC and MUC5B, in a dose- and time-dependent manner, at the gene and protein levels. Leptin-induced mucin expression was inhibited by the leptin receptor antagonist. Conclusions: The increased expression of leptin receptors in nasal polyps implies leptin has a certain role in nasal polyposis. In addition, leptin appears to induce the expression of MUC5AC and MUC5B through leptin receptors in the human nasal polyp epithelial cells. Laryngoscope, 2010 [source]

Leptin and the metabolic syndrome in patients with myotonic dystrophy type 1

ACTA NEUROLOGICA SCANDINAVICA, Issue 2 2010
V. Rakocevic Stojanovic
Rakocevic Stojanovic V, Peric S, Lavrnic D, Popovic S, Ille T, Stevic Z, Basta I, Apostolski S. Leptin and the metabolic syndrome in patients with myotonic dystrophy type 1. Acta Neurol Scand: 2010: 121: 94,98. © 2009 The Authors Journal compilation © 2009 Blackwell Munksgaard. Objectives,,, To evaluate serum leptin concentration and its relation to metabolic syndrome (MSy) in non-diabetic patients with myotonic dystrophy type 1 (DM1). Materials and methods,,, This study included 34 DM1 patients, and the same number of healthy subjects matched for age, sex and body mass index (BMI). Results,,, DM1 patients had increased BMI and insulin resistance, and increased leptin and insulin concentrations, but the other features of MSy such as diabetes, glucose intolerance and hypertension were not detected in DM1 patients. Serum leptin levels were higher in patients with DM1 than in healthy controls (8.5 ± 6.6 ng/ml vs 3.6 ± 2.9 ng/ml in men, and 13.9 ± 10.0 ng/ml vs 10.9 ± 6.9 ng/ml in women, respectively). In DM1 patients, leptin levels correlated with BMI, fasting insulin and insulin resistance (HOMA) (P < 0.01). Conclusions,,, The leptin overproduction correlated with insulin resistance in DM1 patients but the significance of this finding remains unclear. [source]

Sex-specific association between leptin receptor polymorphisms and leptin levels and BMI in healthy adolescents,

ACTA PAEDIATRICA, Issue 10 2010
P Riestra
Abstract Aim:, To examine the relationship of three common polymorphisms in the leptin receptor (LEPR) gene, implicated in the regulation of body weight, with leptin levels and obesity-related phenotypes in a population-based sample of healthy pubertal children in Spain. Methods:, The study included 806 boys and girls aged 12,16 whose anthropometrical data and body composition were recorded. Serum leptin levels were determined by ELISA. The LEPR Q223R, K109R and K656N polymorphisms were determined by TaqMan® allelic discrimination assays. Results:, When analysing the Q223R polymorphism, we observed that female carriers of the RR genotype had significantly higher plasma leptin levels (18.2 vs. 15.1 ng/mL p = 0.016) and significantly higher mean BMI values (22.5 vs. 21.3 Kg/m2 p = 0.032) than QR carriers. Furthermore, the frequency of the RR genotype in overweight-obese girls was significantly higher than that found in normal-weight girls. No significant differences were observed in boys. Neither boys nor girls showed significant differences when comparing leptin levels, anthropometric variables or body composition by K109R or K656N genotype. Conclusion:, The fact, that the Q223R polymorphism in the LEPR gene is significantly associated with leptin levels and BMI only in girls, suggests a sex-specific influence of this polymorphism on these variables. [source]

Circulating leptin levels and bone mineral density in children with biliary atresia

ACTA PAEDIATRICA, Issue 2 2008
Sittisak Honsawek
Abstract Aim: To investigate circulating leptin levels in biliary atresia (BA) patients and the association of leptin with bone mineral density (BMD) and the severity of BA. Methods: We have examined 50 patients with BA and 15 matched healthy controls. Serum leptin, osteocalcin and C-terminal telopeptide of type I collagen (CTX) levels were measured by sandwich enzyme-linked immunosorbent assay (ELISA). BMD of the lumbar spine was measured by dual energy X-ray absorptiometry. Results: Serum leptin levels of BA patients were lower than those of healthy controls (2.7 ± 0.3 vs. 7.1 ± 1.7 ng/mL, p = 0.0001). Among the BA patients, serum leptin levels were significantly lower in patients with jaundice than patients without jaundice (1.7 ± 0.2 vs. 3.4 ± 0.4 ng/mL, p = 0.001). BMD of BA patients was correlated (p < 0.001) with leptin levels, age and BMI (r = 0.55, r = 0.75 and r = 0.58, respectively). The serum CTX levels were significantly higher in jaundice patients compared with jaundice-free patients and the healthy controls (0.6 ± 0.2 vs. 0.2 ± 0.1 ng/mL, p = 0.01), whereas the serum osteocalcin levels in BA patients were not different from those in the controls. Conclusion: Circulating leptin levels are correlated with BMD and the presence of jaundice in BA, suggesting that the leptin may play a physiological role in maintaining bone mass of BA patients with jaundice. [source]

Relation of serum leptin and insulin-like growth factor-1 levels to intima-media thickness and functions of common carotid artery in children and adolescents with type 1 diabetes

ACTA PAEDIATRICA, Issue 8 2004
ME Atabek
Background and aim: Leptin and insulin-like growth factor-1 (IGF-1) have been suggested to be involved in the pathogenesis of atherosclerosis. The aim of this study was to evaluate the relationship between serum leptin, IGF-1 and intima-media thickness (IMT) and functions of common carotid artery (CCA) in children and adolescent patients with type 1 diabetes. Material and methods: Serum leptin and IGF-1 levels were measured in 45 diabetic patients (23 girls and 22 boys). Age, diabetes duration as well as major cardiovascular risk factors, including anthropometric and metabolic parameters, were matched between girls and boys. The relation of serum leptin and IGF-1 levels to CCA structure and functions were measured by ultrasonography as IMT, cross-sectional compliance (CSC), cross-sectional distensibility (CSD), diastolic wall stress (DWS) and incremental elastic modulus (IEM). Results: Serum leptin levels of diabetic girls were higher than those in the boys (21.8 ± 14.5 ,g/1 vs 8.9 ± 10.6 ,.g/1, p= 0.002). However, the difference for serum IGF-1 levels was not significant between diabetic girls and boys (240.7 ± 96.8 ,g/ml vs 234.7 ± 93.2 ng/ml; p < 0.05). In all subjects, leptin levels were correlated with CSC (p= 0.04), CSD (p= 0.04) and IEM (p= 0.01), and IGF-I levels were only correlated with CSC (p= 0.01). Leptin did not show any correlation with ultrasonographic measurements in both girls and boys separately. IGF-1 was correlated with CSC (p= 0.001), CSD (p= 0.002) and IEM (p > 0.001) in boys but not in girls. In a multivariate regression model, IGF-1 emerged as independent correlates for mean CSD and IEM in boys but not in girls. Conclusion: Serum leptin and IGF-1 levels in children and adolescent patients with type 1 diabetes are associated with functions of common carotid artery, and the association of IGF-1 levels is influenced by sex. [source]

The changes in serum leptin, body fat mass and insulin resistance after renal transplantation

CLINICAL TRANSPLANTATION, Issue 1 2003
S Mehmet Kayacan
Abstract:,Background:, In this prospective-controlled study, we aimed to investigate the effect of changes in insulin resistance and anthropometrical parameters on serum leptin levels (SLL) after renal transplantation (Tx). Patients and methods:, Thirty-four patients (M/F: 19/15, mean age: 29 ± 9 yr) and 30 age and sex-matched healthy controls (C) were included. Body weight, subscapular, suprailiac, periumbilical, biceps and triceps skinfold thicknesses, neck, wrist, hip and waist circumferences, as well as body mass index and body fat mass were measured as anthropometrical parameters. In order to measure the serum glucose, insulin and SLL, blood samples were obtained before and 1 wk, 1 and 6 months after Tx. Homeostasis Model Assessment (HOMA) values were calculated as an index of insulin resistance. Results:, Serum leptin levels (SLL) of the patients at pre-Tx were significantly higher than C (21.5 ± 3.5 vs. 7.8 ± 0.9 ng/mL, p = 0.002) and decreased at first week after Tx (from 21.5 ± 3.5 to 8.4 ± 1.5 ng/mL, p < 0.001). Thereafter, it gradually increased to 12.8 ± 2.1 ng/mL in the first month and to 14.4 ± 2.1 ng/mL in the sixth month after Tx. Serum leptin levels at sixth month were significantly higher than C (p = 0.005). Serum insulin and HOMA values changed similar to SLL after Tx. Correlations between SLL and HOMA persisted during the study period [pre-Tx (r: 0.40) and at first (r: 0.38) and sixth (r: 0.47) months]. In linear regression analysis, HOMA and fat mass were found as independent variables for predicting SLL at the sixth month after Tx. Conclusion:, Serum leptin levels dramatically decreased immediately after Tx and significantly correlated with serum insulin levels and HOMA during the entire study. Increase in SLL at sixth months was probably because of increase in fat mass, insulin resistance and steroid use in renal transplant recipients. [source]

Diagnostic value of leptin in tuberculous pleural effusions

INTERNATIONAL JOURNAL OF CLINICAL PRACTICE, Issue 11 2006
G. CELIK
Summary It is suggested that leptin may be involved in inflammation. Although relation between leptin levels and active pulmonary tuberculosis has been studied, there is no information about relation between leptin levels and tuberculous pleural effusions (TPE). We evaluated the diagnostic value of pleural fluid and serum leptin levels in TPE and compared them with adenosine deaminase (ADA). Forty-five patients, 17 tuberculous effusion and 28 nontuberculous effusion, with exudative pleural effusions were included. Leptin and ADA levels were measured from serum and pleural fluid in all patients. There were no statistically significant differences between tuberculous and nontuberculous groups with respect to the serum ADA activity and pleural fluid/serum leptin ratio. On the contrary, pleural fluid leptin level, pleural fluid ADA activity, serum leptin level and pleural fluid/serum ADA activity ratio were statistically different between tuberculous and nontuberculous groups. When leptin levels were corrected for body mass index, serum leptin levels did not reach statistical significance. Cut-off points to predict tuberculosis were calculated as 9.85 ng/ml and 35.55 U/l for pleural fluid leptin level and pleural fluid ADA activity, respectively. Sensitivity, specificity and area under the curve ± standard error were 82.4%, 82.1%, 0.83 ± 0.07 for pleural fluid leptin levels and 100%, 100%, 1.00 ± 0.00 for pleural fluid ADA activity, respectively; the difference between these curves was significant (p = 0.01). Pleural fluid leptin levels were lower in tuberculous effusions than in other exudates. Pleural fluid leptin has a diagnostic value for TPE but not as good as that of ADA. [source]

Is Leptin the Link Between Fat and Bone Mass?,

JOURNAL OF BONE AND MINERAL RESEARCH, Issue 9 2002
Thierry Thomas Ph.D.
Abstract Recently, leptin has emerged as a potential candidate responsible for protective effects of fat on bone tissue. However, it remains difficult to draw a clear picture of leptin effects on bone metabolism because published data are sometimes conflicting or apparently contradictory. Beyond differences in models or experimental procedures, it is tempting to hypothesize that leptin exerts dual effects depending on bone tissue, skeletal maturity, and/or signaling pathway. Early in life, leptin could stimulate bone growth and bone size through direct angiogenic and osteogenic effects on stromal precursor cells. Later, it may decrease bone remodeling in the mature skeleton, when trabecular bone turnover is high, by stimulating osteoprotegerin (OPG) expression. Leptin negative effects on bone formation effected through central nervous system pathway could counterbalance these peripheral and positive effects, the latter being predominant when the blood-brain barrier permeability decreases or the serum leptin level rises above a certain threshold. Thus, the sex-dependent specificity of the relationship between leptin and bone mineral density (BMD) in human studies could be, at least in part, caused by serum leptin levels that are two- to threefold higher in women than in men, independent of adiposity. Although these hypotheses remain highly speculative and require further investigations, existing studies consistently support the role of leptin as a link between fat and bone. [source]

Estimation of serum leptin in oral squamous cell carcinoma

JOURNAL OF ORAL PATHOLOGY & MEDICINE, Issue 1 2010
Harshkant P. Gharote
J Oral Pathol Med (2010) 39: 69,73 Background:, Cachexia contributes significantly to mortality in cancer patients; role of cytokines in inducing cachexia is an emerging view. Leptin, a homologous protein of cytokine family, is found to be decreased in serum with cachexia. The purpose of this study was to compare serum leptin levels of oral squamous cell carcinoma patients with that of control group and correlate it with body mass index. Method:, Serum samples of 31 oral squamous cell carcinoma patients and that of 28 healthy individuals were subjected to evaluation of serum leptin levels (ng/ml) using enzyme-linked immunosorbent assay. Results:, A significant reduction in leptin level of oral squamous cell carcinoma patients was observed. Definite correlation between body mass index and serum leptin and also between serum leptin levels of various histopathological variants of oral squamous cell carcinoma was observed. Conclusion:, The results of this study suggest that evaluation of serum leptin level can provide status of cachexia in oral squamous cell carcinoma patients. [source]

Lack of association between leptin G2548A gene polymorphism and Behçet's disease

JOURNAL OF THE EUROPEAN ACADEMY OF DERMATOLOGY & VENEREOLOGY, Issue 1 2007
F Aydin
Abstract Background, Behçet's disease is a chronic, multisystem, inflammatory disease characterized by the predominance of T-helper 1 cytokines. The disease is also characterized by infiltration of lymphocytes and neutrophils into the affected tissues. Because cytokines are involved in the regulation of lymphocyte and phagocyte functions, they may play an important role in the pathogenesis of Behçet's disease. Leptin, a member of the gp 130 family of cytokines, induces a strong T-helper 1 response and is regarded as a proinflammatory inducer. Recent studies have shown that serum leptin concentration was increased in patients with Behçet's disease and correlated with disease activity. Objectives, We aimed to investigate the role of G2548A polymorphism of leptin gene in patients with Behçet's disease and compare the results with healthy controls. Patients and methods, A total of 93 subjects with Behçet's disease and 125 healthy controls were included in this study. Analyses of G-2548A polymorphism of the LEP gene were performed using the PCR-restriction fragment length polymorphism technique. The genotypes (GG, GA, and AA of leptin G2548A) and alleles (G and A of leptin 2548) were scored and the frequency was estimated. The frequencies of the alleles and genotypes in patients and controls were compared. We analysed the correlation between leptin gene polymorphism and the clinical features of BD. Results, Both genotype and allele frequencies were not significantly different between controls and Behçet's disease patients [OR = 0.67, 95% CI (0.35,1.29), P = 0.197 and OR = 0.77, 95% CI (0.52,1.15), P = 0.184]. We did not find any significant relationship between leptin gene polymorphism and the clinical features of BD (P > 0.05). Conclusion, In the present case-control study, we found no evidence of an association between the G-2548A variant of the leptin gene and BD among Turks. Further studies are needed to investigate serum leptin level to explain the mechanisms behind the lack of association between leptin G2548A gene polymorphism and BD. [source]

Psoriasis arthropathica associated with severe obesity showing high serum leptin level

THE JOURNAL OF DERMATOLOGY, Issue 6 2009
Hidehisa SAEKI
No abstract is available for this article. [source]

Serum leptin correlates in infertile oligozoospermic males

ANDROLOGIA, Issue 5 2007
S. Hanafy
Summary Leptin is an adipocyte-secreted protein that participates in the regulation of energy homeostasis. Eighty men were investigated; fertile normozoospermia as a control (n = 30) and infertile oligozoospermia (n = 50). The patients underwent estimation of body weight (kg), height (cm), calculation of body mass index (BMI), semen analysis, serum leptin and testosterone hormones. Mean body weight was significantly higher in infertile oligozoospermia compared with controls. Mean height, BMI and serum testosterone levels showed nonsignificant differences between the two groups. Infertile oligozoospermia had significantly higher mean serum leptin level than controls (mean ± SD; 6.88 ± 8.65, 16.3 ± 13.98 ng ml,1, P < 0.01). Serum leptin demonstrated significant positive correlation with age, body weight, BMI and significant inverse correlation with serum testosterone. It had nonsignificant correlation with the height and sperm concentration. These results are suggestive of a link between the adipocyte derived hormone, leptin and male reproduction. [source]

The Relationship Between Leptin Level and Oxidative Status Parameters in Hemodialysis Patients

Effects of a natural extract of (,)-hydroxycitric acid (HCA-SX) and a combination of HCA-SX plus niacin-bound chromium and Gymnema sylvestre extract on weight loss

DIABETES OBESITY & METABOLISM, Issue 3 2004
H. G. Preuss
Aim:, The efficacy of optimal doses of highly bioavailable (,)-hydroxycitric acid (HCA-SX) alone and in combination with niacin-bound chromium (NBC) and a standardized Gymnema sylvestre extract (GSE) on weight loss in moderately obese subjects was evaluated by monitoring changes in body weight, body mass index (BMI), appetite, lipid profiles, serum leptin and excretion of urinary fat metabolites. HCA-SX has been shown to reduce appetite, inhibit fat synthesis and decrease body weight without stimulating the central nervous system. NBC has demonstrated its ability to maintain healthy insulin levels, while GSE has been shown to regulate weight loss and blood sugar levels. Methods:, A randomized, double-blind, placebo-controlled human study was conducted in Elluru, India for 8 weeks in 60 moderately obese subjects (ages 21,50, BMI >26 kg/m2). Subjects were randomly divided into three groups. Group A was administered HCA-SX 4667 mg, group B was administered a combination of HCA-SX 4667 mg, NBC 4 mg and GSE 400 mg, while group C was given placebo daily in three equally divided doses 30,60 min before meals. All subjects received a 2000 kcal diet/day and participated in supervised walking. Results:, At the end of 8 weeks, body weight and BMI decreased by 5,6% in both groups A and B. Food intake, total cholesterol, low-density lipoproteins, triglycerides and serum leptin levels were significantly reduced in both groups, while high-density lipoprotein levels and excretion of urinary fat metabolites increased in both groups. A marginal or non-significant effect was observed in all parameters in group C. Conclusion:, The present study shows that optimal doses of HCA-SX and, to a greater degree, the combination of HCA-SX, NBC and GSE can serve as an effective and safe weight-loss formula that can facilitate a reduction in excess body weight and BMI, while promoting healthy blood lipid levels. [source]

Serum Levels of Leptin As Marker For Patients At High Risk of Gastric Cancer

HELICOBACTER, Issue 6 2009
Lisette G. Capelle
Abstract Background:, Serological screening for gastric cancer (GC) may reduce mortality. However, optimal serum markers for advanced gastric precursor lesions are lacking. Aim:, To evaluate in a case,control study whether serum leptin levels correlate with intestinal metaplasia (IM) and can serve as a tool to identify patients at high risk for GC. Materials and Methods:, Cases were patients with a previous diagnosis of IM or dysplasia, controls were patients without such a diagnosis. All patients underwent endoscopy. Fasting serum was collected for the measurement of leptin, pepsinogens I/II, gastrin, and Helicobacter pylori. Receiver operating characteristic (ROC) curves and their area under the curve (AUC) were provided to compare serum leptin levels with other serological markers. Results:, One hundred nineteen cases and 98 controls were included. In cases, the median leptin levels were 116.6 pg/mL versus 81.9 pg/mL in controls (p = .01). After adjustment for age, sex and BMI, leptin levels remained higher in cases than in controls (p < .005). In multivariate analysis, male sex (p = .002), age (<0.001), low pepsinogen levels (p = .004) and high leptin levels (p = .04) were independent markers for the presence of IM. In addition, a ROC curve including age, sex and pepsinogen I levels had an AUC of 0.79 (95% CI (0.73,0.85)). Adding serum leptin levels increased the AUC to 0.81 (95% CI (0.75,0.86)). Conclusions:, High leptin levels are associated with an increased risk of IM. Moreover, serum leptin levels are a significant independent marker for the presence of IM. However, in combination with the serological test for pepsinogen I the additional value of serum leptin levels is rather limited. [source]

Diagnostic value of leptin in tuberculous pleural effusions

Impaired Energetic Metabolism After Central Leptin Signaling Leads to Massive Appendicular Bone Loss in Hindlimb-Suspended Rats,

JOURNAL OF BONE AND MINERAL RESEARCH, Issue 12 2008
Aline Martin
Abstract We previously showed in rats that the leptin effects on bone were dose dependent. Positive effects were observed when serum leptin concentration was in a physiological range. In contrast, important increases in serum leptin levels led to negative effects on bone formation similar to those reported after intracerebroventricular leptin administration in mice. To clarify whether leptin effects on bone depend on administration route and/or animal model, female rats were hindlimb unloaded or not and treated either with intracerebroventricular infusion of leptin or vehicle for 14 days. By increasing cerebrospinal fluid (CSF) leptin concentration, intracerebroventricular infusion of leptin significantly reduced food intake and consequently body weight, abdominal fat, and lean mass of the animals. Leptin infusion inhibited bone elongation over the 14 days and blunted cortical bone thickening at the femoral diaphysis site. Interestingly, leptin effects were site dependent in the cancellous bone envelopes, because tibia metaphysis BMD was lower and lumbar spine BMD was higher under intracerebroventricular leptin. Treated groups showed reduced bone remodeling independently of hindlimb unloading. Multiple downstream pathways were implicated in the mediation of these negative leptin effects on bone including not only stimulation of the sympathetic nervous system but also a decrease in somatotropic axis activity. Therefore, the intracerebroventricular leptin-induced bone loss could be largely related to the concurrent alteration of energetic and metabolic status. In summary, our study supports the hypothesis of a concentration-dependent balance between peripheral and central control of leptin on bone. [source]

Cholesterol-Sensing Receptors, Liver × Receptor , and ,, Have Novel and Distinct Roles in Osteoclast Differentiation and Activation

JOURNAL OF BONE AND MINERAL RESEARCH, Issue 8 2006
Kirsten M Robertson
Abstract The liver × receptor (,,,) is responsible for regulating cholesterol homeostasis in cells. However, our studies using the LXR,,/,, LXR,,/,, and LXR,,/,,,/, mice show that both LXR, and , are also important for bone turnover, mainly by regulating osteoclast differentiation/activity. Introduction: The liver × receptors (,,,) are primarily responsible for regulating cholesterol homeostasis within cells and the whole body. However, as recent studies show that the role for this receptor is expanding, we studied whether the LXRs could be implicated in bone homeostasis and development. Materials and Methods: pQCT was performed on both male and female LXR,,/,, LXR,,/,, LXR,,/,,,/,, and WT mice at 4 months and 1 year of age. Four-month-old female mice were additionally analyzed with reference to qPCR, immunohistochemistry, histomorphometry, transmission electron microscopy, and serum bone turnover markers. Results: At the mRNA level, LXR, was more highly expressed than LXR, in both whole long bones and differentiating osteoblast-like MC3T3-E1 and osteoclast-like RAW 264.7 cells. Four-month-old female LXR,,/, mice had a significant increase in BMD because of an increase in all cortical parameters. No difference was seen regarding trabecular BMD. Quantitative histomorphometry showed that these mice had significantly more endosteal osteoclasts in the cortical bone; however, these cells appeared less active than normal cells as suggested by a significant reduction in serum levels of cross-linked carboxyterminal telopeptides of type I collagen (CTX) and a reduction in bone TRACP activity. Conversely, the female LXR,,/, mice exhibited no change in BMD, presumably because a significant decline in the number of the trabecular osteoclasts was compensated for by an increase in the expression of the osteoclast markers cathepsin K and TRACP. These mice also had a significant decrease in serum CTX, suggesting decreased bone resorption; however, in addition presented with an increase in the expression of osteoblast associated genes, bone formation markers, and serum leptin levels. Conclusions: Our findings show that both LXRs influence cellular function within the bone, with LXR, having an impact on osteoclast activity, primarily in cortical bone, whereas LXR, modulates trabecular bone turnover. [source]

Is Leptin the Link Between Fat and Bone Mass?,

Inverse relationship between circulating levels of leptin and bone mineral density in chronic liver disease

JOURNAL OF GASTROENTEROLOGY AND HEPATOLOGY, Issue 12 2001
Sif Ormarsdóttir
Abstract Background and Aim: The pathophysiology of osteoporosis complicating chronic liver disease is unknown. Recent animal studies have found leptin to be a potent inhibitor of bone formation. The aim of this study was to investigate the relationship between serum leptin levels and bone mineral density in patients with chronic liver disease. Methods: Fifty-eight patients, 39 females and 19 males, and age- and gender-matched controls were included. Bone mineral density was measured by using dual energy X-ray absorptiometry. Serum leptin was measured by using a radioimmunoassay. Results: The mean serum leptin concentration was 10.4 ± 11.3 and 15.2 ± 17.9 ng/mL; P = 0.11, in the patients and controls, respectively. Leptin correlated positively with body mass index in patients (r = 0.40; P = 0.003) and in controls (r = 0.55; P < 0.0001). In patients classified as Child,Pugh grade B and C, serum leptin correlated negatively with bone mineral density in females at both the lumbar spine and the femoral neck (r = ,0.78; P = 0.04 and r = ,0.86; P = 0.03, respectively). In male patients, the correlation was only significant at the lumbar spine (r = ,0.99; P = 0.002 and r = ,0.86; P = 0.06, at the lumbar spine and femoral neck, respectively). No correlation was found between serum leptin and bone mineral density in the controls. Conclusion: An inverse relationship between serum leptin and bone mineral density was found in patients with advanced chronic liver disease. The reasons for these findings are uncertain, but a pathophysiological role of circulating leptin in osteoporosis in chronic liver disease is possible. [source]

Large differences in serum leptin levels between nonwesternized and westernized populations: the Kitava study

JOURNAL OF INTERNAL MEDICINE, Issue 6 2001
S. Lindeberg
Abstract.,Lindeberg S, Söderberg S, Ahrén B, Olsson T (Lund University; and Umeå University, Malmö, Sweden). Large differences in serum leptin levels between nonwesternized and westernized populations: the Kitava study. J Intern Med 2001; 249: 553,558. Objectives.,To compare serum leptin between nonwesternized and westernized populations. Setting., (i) The tropical island of Kitava, Trobriand Islands, Papua New Guinea and (ii) the Northern Sweden MONICA study population. Design.,Cross-sectional survey. Methods.,Fasting levels of serum leptin were analysed in 163 randomly selected Kitavans aged 20,86 years and in 224 Swedes aged 25,74. Main outcome measures.,Mean and determinants of serum leptin. Results.,Geometric mean of serum leptin in Kitavan males and females were 1.5 and 4.0 vs. 4.9 and 13.8 ng mL,1 in Swedish male and females (P < 0.0001 for both sexes). In Kitavans, observed geometric mean were close to predicted levels (1.8 ng mL,1 for males and 4.5 ng mL,1 for females) based on multiple linear regression equations including body mass index (BMI), triceps skinfolds (TSF) and age from the Swedish population-based sample. In Kitavans serum leptin was positively related to TSF amongst both sexes and, amongst females, to BMI. In Kitavans leptin was not related to fasting serum insulin. TSF explained 55% of the variation of leptin amongst females. There was a slight age-related increase of leptin amongst males. In Kitava leptin was not related to fasting serum insulin which was substantially lower than in Sweden. Conclusion.,The low concentrations of serum leptin amongst Kitavans probably relates to the absence of overweight and hyperinsulinaemia. At a population level serum leptin can apparently be predicted from simple measures of adiposity. [source]

Estimation of serum leptin in oral squamous cell carcinoma

Weight loss, body fat mass, and leptin in Parkinson's disease,

MOVEMENT DISORDERS, Issue 6 2009
Birgitta Lorefält RNT
Abstract Weight loss is a common problem in Parkinson's disease (PD), but the causative mechanisms behind this weight loss are unclear. We compared 26 PD patients with sex and age matched healthy controls. Examinations were repeated at baseline, after one and after two years. Body fat mass was measured by Dual X-ray Absorptiometry (DXA). Seventy three per cent of the PD patients lost body weight. Loss of body fat mass constituted a considerable part of the loss of body weight. In the patients who lost weight, serum leptin levels were lower than in those who did not lose weight. The relationship between low body fat mass and low leptin levels seems to be relevant, at least for female PD patients. It is reasonable to believe that low leptin levels in these patients could be secondary to the decreased body fat mass. © 2009 Movement Disorder Society [source]

Ghrelin and leptin modulate immunity and liver function in overweight children

PEDIATRICS INTERNATIONAL, Issue 1 2009
Yuki Okamatsu
Abstract Background:, The rising prevalence of obesity represents a growing worldwide public health problem. Interactions of adipocytokines and low-grade systemic inflammation presently are considered important in the development of obesity, as well as associated chronic disease including bronchial asthma, obesity-related liver disease and type 2 diabetes mellitus. The purpose of the present study was to investigate metabolic, hormonal, immunologic and inflammatory factors in overweight children and to further clarify possible immunomodulatory effects of obesity-related hormones and cytokines. Methods:, Forty-nine prepubertal overweight children and 49 age-matched controls of normal weight without underlying disease were enrolled. Levels of plasma ghrelin and serum leptin, cytokines (interleukin [IL]-4, IL-10, IL-12, 1L-13), C-reactive protein, immunoglobulin, and insulin were measured, and liver function tests were done to better understand their status in the setting of obesity. Results:, Overweight subjects had significantly higher measures of adiposity (body mass indexI, % body fat) and had significantly higher serum levels of IgG, IgA and IgE than non-obese children (P = 0.038, 0.0043, 0.0034, respectively); the opposite was true for IgM (P = 0.025). The incidence of presumed non-alcoholic fatty liver disease was 28.6% in overweight children. In overweight children, serum leptin levels were associated with liver function index (aspartate aminotransferase/alanine aminotransferase ratio) and serum insulin levels. Some elevated immunoglobulin levels significantly correlated with plasma ghrelin levels and liver function index. Conclusions:, It is possible that appetite-regulating hormones modulate both humoral immunity and liver function. Further studies with a larger number of subjects are needed to clarify the precise mechanisms of this association. [source]

Is leptin a predictive factor in the end of therapy response in chronic hepatitis B?

PEDIATRICS INTERNATIONAL, Issue 4 2005
Mukadder Ayle Selimo}lu
Abstract, Background:,The purpose of this study was to determine the leptin levels in children with chronic hepatitis B virus (HBV) infection, and to evaluate the effect of serum leptin levels on the end of therapy response (ETR). It is known that leptin stimulates T-cell immunity and so T-cell mediated immune response is critical in the outcome of chronic HBV infection. Methods:,Leptin levels in children with chronic HBV infection were investigated and its effects on the ETR in 24 children who were treated with interferon-, and lamivudine combination therapy were evaluated. Results:,The mean leptin level of the patients was higher than that of healthy children (P = 0.034). Of the patients, seven (29.2%) had ETR. The mean hepatic activity index and portal inflammation score were higher, the HBV DNA was lower, and the leptin level was similar in children with ETR when compared to others (P = 0.017, P = 0.04, P = 0.007, P = 0.34, respectively). HBV DNA and the fibrosis score were positively correlated (P = 0.016). Conclusion:,Although the higher leptin value observed in children with ETR was not statistically significant, because of close interactions between leptin, cytokines and lymphocytes, it is thought that leptin should be investigated as a predictive factor of ETR in further studies. [source]

Relationship between serum leptin and thyroid hormones in children

PEDIATRICS INTERNATIONAL, Issue 3 2000
MAKOTO UCHIYAMA, Tadashi Asami TATIANA CIOMARTEN
Abstract Background: Because leptin decreases food intake and increases energy expenditure, the possible influence of thyroid status on the leptin system has been investigated mainly in adults and animals. However, the data available at present are very confusing. The aim of the present study was to assess the possible interaction of thyroid hormones with the leptin system. Methods: Serum free thyroxine (FT4), a biologically active thyroid hormone, and thyroid stimulating hormone (TSH), a sensitive and reliable index of thyroid status, were examined in 51 children (19 males, 32 females) with mass screening-detected congenital hypothyroidism on continuous L -thyroxine (L-T4) substitution therapy. The subjects were divided into younger (n=35, aged 1 month , 5 years) and older (n=16, 6 years , 11 years) children groups. Serum levels of leptin and thyroid hormones were measured in the subjects. Body mass index (BMI) was estimated by the formula bodyweight (kg)/height`height (m 2), which is known as the Kaup index in younger children and BMI in older children and adults. Results: In the younger children group, serum leptin levels showed no correlation with serum TSH, FT4 or T4. In the older children group, serum leptin concentrations significantly correlated with T4 (r=0.510, P<0.05) and BMI (n=16, r=0.647, P<0.01), but not with TSH or FT4. Conclusion: The role of thyroid hormones in modulating leptin synthesis and secretion seems to have little, if any, clinical or biological relevance. [source]

Reduced fat oxidation and obesity risks among the Buryat of Southern Siberia,

AMERICAN JOURNAL OF HUMAN BIOLOGY, Issue 5 2009
William R. Leonard
Over the last 20 years, obesity and associated metabolic diseases have emerged as major global health problems. Among urbanizing populations of developing regions of the world, childhood undernutrition often coexists with adult overnutrition, a phenomenon known as the "dual nutritional burden". A recent work (Frisancho 2003: Am J Hum Biol 15:522,532) suggests that linear growth stunting in early childhood may contribute to adult obesity by reducing the body's ability to oxidize fat. We test central aspects of this model drawing on data from 112 adult Buryat herders (53 males; 59 females) from Southern Siberia. The results are consistent with the predictions of the model, but only for women. Shorter Buryat women (height-for-age Z -scores , ,1) have significantly lower fasting fat oxidation levels compared to their taller counterparts. Shorter women are also significantly heavier and fatter, and have higher serum lipid levels. Among all Buryat women, reduced fat oxidation is significantly correlated with percent body fatness, serum triglyceride levels, and serum leptin levels, after controlling for relevant covariates. Additionally, Buryat women with high dietary fat intakes and low fat oxidation are significantly fatter and have higher lipid and leptin levels than those with low fat intakes and high fat oxidation. These results suggest that developmental changes in fat oxidation may play a role in the origins of obesity among populations with high rates of linear growth stunting. Further longitudinal research is necessary to elucidate the pathways through which early-life undernutrition may increase risks for adulthood obesity and cardiovascular disease. Am. J. Hum. Biol. 2009. © 2009 Wiley-Liss, Inc. [source]