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Phenotypic effects of leptin replacement on morbid obesity, diabetes mellitus, hypogonadism, and behavior in leptin-deficient adults.

ABSTRACT: Genetic mutations in the leptin pathway can be a cause of human obesity. It is still unknown whether leptin can be effective in the treatment of fully established morbid obesity and its endocrine and metabolic consequences in adults. To test the hypothesis that leptin has a key role in metabolic and endocrine regulation in adults, we examined the effects of human leptin replacement in the only three adults identified to date who have genetically based leptin deficiency. We treated these three morbidly obese homozygous leptin-deficient adult patients with recombinant human leptin at low, physiological replacement doses in the range of 0.01-0.04 mg/kg for 18 months. Patients were hypogonadal, and one of them also had type 2 diabetes mellitus. We chose the doses of recombinant methionyl human leptin that would achieve normal leptin concentrations and administered them daily in the evening to model the normal circadian variation in endogenous leptin. The mean body mass index dropped from 51.2 +/- 2.5 (mean +/- SEM) at baseline to 26.9 +/- 2.1 kg/m2 after 18 months of treatment, mainly because of loss of fat mass. We document here that leptin replacement therapy in leptin-deficient adults with established morbid obesity results in profound weight loss, increased physical activity, changes in endocrine function and metabolism, including resolution of type 2 diabetes mellitus and hypogonadism, and beneficial effects on ingestive and noningestive behavior. These results highlight the role of the leptin pathway in adults with key effects on the regulation of body weight, gonadal function, and behavior.

SUBMITTER: Licinio J

PROVIDER: S-EPMC384781 | biostudies-literature | 2004 Mar

REPOSITORIES: biostudies-literature

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Phenotypic effects of leptin replacement on morbid obesity, diabetes mellitus, hypogonadism, and behavior in leptin-deficient adults.

Licinio Julio J Caglayan Sinan S Ozata Metin M Yildiz Bulent O BO de Miranda Patricia B PB O'Kirwan Fiona F Whitby Robert R Liang Liyin L Cohen Pinchas P Bhasin Shalender S Krauss Ronald M RM Veldhuis Johannes D JD Wagner Anthony J AJ DePaoli Alex M AM McCann Samuel M SM Wong Ma-Li ML

Proceedings of the National Academy of Sciences of the United States of America 20040309 13

Genetic mutations in the leptin pathway can be a cause of human obesity. It is still unknown whether leptin can be effective in the treatment of fully established morbid obesity and its endocrine and metabolic consequences in adults. To test the hypothesis that leptin has a key role in metabolic and endocrine regulation in adults, we examined the effects of human leptin replacement in the only three adults identified to date who have genetically based leptin deficiency. We treated these three mo ...[more]

PMID: 15070752

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Project description:Background There is a paucity of outcome data on patients who are morbidly obese (MO) undergoing transcatheter aortic valve replacement. We aimed to determine their periprocedural and midterm outcomes and investigate the impact of obesity phenotype. Methods and Results Consecutive patients who are MO (body mass index, ≥40 kg/m2, or ≥35 kg/m2 with obesity-related comorbidities; n=910) with severe aortic stenosis who underwent transcatheter aortic valve replacement in 18 tertiary hospitals were compared with a nonobese cohort (body mass index, 18.5-29.9 kg/m2, n=2264). Propensity-score matching resulted in 770 pairs. Pre-transcatheter aortic valve replacement computed tomography scans were centrally analyzed to assess adipose tissue distribution; epicardial, abdominal visceral and subcutaneous fat. Major vascular complications were more common (6.6% versus 4.3%; P=0.043) and device success was less frequent (84.4% versus 88.1%; P=0.038) in the MO group. Freedom from all-cause and cardiovascular mortality were similar at 2 years (79.4 versus 80.6%, P=0.731; and 88.7 versus 87.4%, P=0.699; MO and nonobese, respectively). Multivariable analysis identified baseline glomerular filtration rate and nontransfemoral access as independent predictors of 2-year mortality in the MO group. An adverse MO phenotype with an abdominal visceral adipose tissue:subcutaneous adipose tissue ratio ≥1 (VAT:SAT) was associated with increased 2-year all-cause (hazard ratio [HR], 3.06; 95% CI, 1.20-7.77; P=0.019) and cardiovascular (hazard ratio, 4.11; 95% CI, 1.06-15.90; P=0.041) mortality, and readmissions (HR, 1.81; 95% CI, 1.07-3.07; P=0.027). After multivariable analysis, a (VAT:SAT) ratio ≥1 remained a strong predictor of 2-year mortality (hazard ratio, 2.78; P=0.035). Conclusions Transcatheter aortic valve replacement in patients who are MO has similar short- and midterm outcomes to nonobese patients, despite higher major vascular complications and lower device success. An abdominal VAT:SAT ratio ≥1 identifies an obesity phenotype at higher risk of adverse clinical outcomes.

Project description:BACKGROUND: Obesity is a multifactorial disease that arises from complex interactions between genetic predisposition and environmental factors. Leptin is central to the regulation of energy metabolism and control of body weight in mammals. METHODOLOGY/PRINCIPAL FINDINGS: To better recapitulate the complexity of human obesity syndrome, we applied N-ethyl-N-nitrosourea (ENU) mutagenesis in combination with a set of metabolic assays in screening mice for obesity. Mapping revealed linkage to the chromosome 6 within a region containing mouse Leptin gene. Sequencing on the candidate genes identified a novel T-to-A mutation in the third exon of Leptin gene, which translates to a V145E amino acid exchange in the leptin propeptide. Homozygous Leptin(145E/145E) mutant mice exhibited morbid obesity, accompanied by adipose hypertrophy, energy imbalance, and liver steatosis. This was further associated with severe insulin resistance, hyperinsulinemia, dyslipidemia, and hyperleptinemia, characteristics of human obesity syndrome. Hypothalamic leptin actions in inhibition of orexigenic peptides NPY and AgRP and induction of SOCS1 and SOCS3 were attenuated in Leptin(145E/145E) mice. Administration of exogenous wild-type leptin attenuated hyperphagia and body weight increase in Leptin(145E/145E) mice. However, mutant V145E leptin coimmunoprecipitated with leptin receptor, suggesting that the V145E mutation does not affect the binding of leptin to its receptor. Molecular modeling predicted that the mutated residue would form hydrogen bond with the adjacent residues, potentially affecting the structure and formation of an active complex with leptin receptor within that region. CONCLUSIONS/SIGNIFICANCE: Thus, our evolutionary, structural, and in vivo metabolic information suggests the residue 145 as of special function significance. The mouse model harboring leptin V145E mutation will provide new information on the current understanding of leptin biology and novel mouse model for the study of human obesity syndrome.

Project description:We will explore the genetic (including APC, k-ras, p53, MSI, etc.) and environmental (including family history, life style, diet, nutritional status, DM, serum IGF-I, IGFBP-3, etc.) risk factors of colorectal tumorigenesis. We will accrue approximately 1000 patients as experimental group. The control group consists of 2000 individuals who were confirmed without colorectal cancer or polyps by colonoscopy. We estimated the statistical power of this study will reach more than 90%. In the second year, we will explore the association between various environmental risk factors with the epigenetic changes of various oncogenes and tumor suppressor genes. Firstly, we will study the correlation between hypermethylation of promoter region of hMLH1 gene with various environmental factors. Next, we will explore the genetic polymorphisms of promoter of E-cadherin gene. Recently, it has been reported that the C→A genetic polymorphism in the promoter region of E-cadherin gene in prostate cancer. Since this phenomenon has not been reported in colorectal cancer, it is mandatory for us to extend our research to the E-cadherin polymorphisms of colorectal cancer. Moreover, this project will focus on exploration of the association between the genetic polymorphisms of promoter of TS gene with chemosensitivity to 5-Fu-based therapy. We speculated that the better prognosis in colorectal tumors with MSI is related to their expression of TS gene. In summary, the second year of this project will extend our accumulated experience in the study of genetic polymorphisms to further clarify the association between genetic polymorphisms of TS gene with the prognosis of colorectal cancers after chemotherapy. We believe that this project will facilitate: (1) the further clarification of colorectal cancer tumorigenesis; (2) the establishment of domestic epidemiological data of colorectal cancer of Taiwan, and (3) the improvement of the quality of clinical management of patients with colorectal cancer.

Dataset Information

Phenotypic effects of leptin replacement on morbid obesity, diabetes mellitus, hypogonadism, and behavior in leptin-deficient adults.

Publications

Phenotypic effects of leptin replacement on morbid obesity, diabetes mellitus, hypogonadism, and behavior in leptin-deficient adults.

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