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3.
Expert Opin Biol Ther ; 15(7): 1061-75, 2015 Jul.
Article in English | MEDLINE | ID: mdl-26063386

ABSTRACT

INTRODUCTION: Metreleptin was recently approved by the Food and Drug Administration for the treatment of generalized lipodystrophy, a condition characterized by leptin deficiency. Its efficacy as hormone replacement therapy suggests broader applications in diseases also characterized by leptin abnormalities, such as familial partial lipodystrophy (FPLD), non-alcoholic fatty liver disease (NAFLD), and common obesity. Metreleptin, in conjunction with other pharmacologic interventions, has the potential to address one of the most widespread epidemics of our time, obesity. AREAS COVERED: This review covers the physiology of leptin, the pharmacologic properties of recombinant methionyl human leptin (R-metHu-Leptin, metreleptin), evidence for metreleptin's efficacy in the treatment of generalized lipodystrophy from both completed and ongoing clinical trials, safety concerns, and future directions in metreleptin research. EXPERT OPINION: Metreleptin's approval for generalized lipodystrophy is the first step in defining and expanding its role to other metabolic diseases. Clinical trials are underway to delineate its efficacy in FPLD, human immunodeficiency virus/highly active anti-retroviral therapy-associated acquired lipodystrophy (HAL), and NAFLD. Additionally, there is growing data that support a therapeutic role in obesity. One of the barriers to development, however, is metreleptin's safety and immunogenicity. Further advances in biologic compatibility are required before metreleptin can be approved for additional indications.


Subject(s)
Leptin/analogs & derivatives , Lipodystrophy, Congenital Generalized/drug therapy , Autoimmunity , Clinical Trials as Topic , Half-Life , Humans , Leptin/chemistry , Leptin/metabolism , Leptin/pharmacokinetics , Leptin/therapeutic use , Lipodystrophy/classification , Lipodystrophy/drug therapy , Lipodystrophy/etiology , Lipodystrophy, Congenital Generalized/classification , Lipodystrophy, Congenital Generalized/etiology , Obesity/drug therapy , Signal Transduction
4.
Rinsho Shinkeigaku ; 47(6): 329-35, 2007 Jun.
Article in Japanese | MEDLINE | ID: mdl-17633104

ABSTRACT

In 2004, heterozygous mutations (N88S, S90L) in the Seipin/BSCL2 gene were identified in two autosomal dominant motor neuron diseases, distal hereditary motor neuropathy type V (OMIM #182960) and Silver syndrome (OMIM #270685). The Seipin/BSCL2 gene was originally identified as a candidate gene for congenital generalized lipodystrophy type 2 (CGL2) (OMIM #269700). Individuals with homozygous null mutations in seipin have severe lipoatrophy, insulin resistance, hypertriglyceridemia, and mental retardation without any abnormality of the motor neurons. Recent phenotype analyses of the N88S and S90L mutations have revealed a wide spectrum of Seipin/BSCL2-related motor neuron diseases, including Silver syndrome, distal hereditary motor neuropathy type V, variants of Charcot-Marie-Tooth disease type 2, and spastic paraplegia 17; therefore, these diseases should be termed "seipinopathies". Seipin is a transmembrane protein that is localized in the endoplasmic reticulum (ER). Interestingly, the N88S and S90L mutations both disturb the N-glycosylation motif, suggesting that improper glycosylation of seipin is closely associated with the pathogenesis of motor neuron diseases. Our recent study demonstrated that seipin is proteolytically cleaved into N and C-terminal fragments and then polyubiquitinated. The N88S and S90L mutations enhance ubiquitination and degradation by UPS, and N88S and S90L mutants appear to be improperly folded, resulting in their accumulation in the ER. Furthermore, expression of mutant seipin in cultured cells activates UPR stress and induces ER stress-mediated apoptosis. Our findings suggest that seipin-related motor neuron diseases, seipinopathies are novel conformational diseases, and we propose that the pathological process of these diseases is tightly associated with ER stress-mediated cell death.


Subject(s)
Endoplasmic Reticulum/genetics , Endoplasmic Reticulum/physiology , GTP-Binding Protein gamma Subunits/genetics , Motor Neuron Disease , Mutation , Oxidative Stress , Apoptosis , Humans , Lipodystrophy, Congenital Generalized/etiology , Motor Neuron Disease/etiology , Proteasome Endopeptidase Complex , Ubiquitin
5.
Am J Med Genet A ; 143A(13): 1421-30, 2007 Jul 01.
Article in English | MEDLINE | ID: mdl-17523150

ABSTRACT

Neonatal progeroid syndrome (NPS), also known as Wiedemann-Rautenstrauch Syndrome, is a rare autosomal recessive disorder characterized by accelerated aging and lipodystrophy from birth. Affected children have extreme intrauterine growth retardation, poor postnatal weight gain, and characteristic facial dysmorphic features such as a triangular shape, pinched nose, pseudohydrocephalus with wide fontanelles and prominent subcutaneous (sc) veins. Generalized loss of sc fat has been reported as a cardinal feature; however, the pattern of fat loss and its association with insulin resistance and its metabolic complications have not been systematically studied. The aim of the current study was to examine body fat distribution and body composition in two girls with NPS using anthropometric measures, whole-body magnetic resonance imaging (MRI) and dual energy X-ray absorptiometry (DEXA), and to assess metabolic complications such as hyperinsulinemia and dyslipidemia. Both the girls (aged 17 years and 10 years, respectively) had generalized paucity of sc fat on physical examination. However, measurements of skin-fold thickness revealed that sc fat was decreased over the extremities, but preserved over the chest and abdomen. MRI studies confirmed the presence of normal amounts of sc truncal fat, and marked loss of fat from the face and distal extremities. Striking fat loss was also noted in the paravertebral and lateral gluteal regions. Interestingly, body composition analysis with DEXA scan revealed a marked reduction in both the fat and lean tissue mass. Fasting glucose, lipids and insulin levels were not elevated. We conclude that patients with NPS do not have generalized lipodystrophy as previously reported, but fat loss is confined to the face, distal extremities, and possibly the paravertebral and lateral gluteal regions. Metabolic abnormalities related to insulin resistance are also uncommon in this condition.


Subject(s)
Body Fat Distribution , Lipodystrophy, Congenital Generalized/diagnosis , Progeria/metabolism , Progeria/pathology , Absorptiometry, Photon , Adolescent , Anthropometry , Body Composition , Child , Female , Humans , Lipodystrophy, Congenital Generalized/etiology , Magnetic Resonance Imaging , Pedigree , Progeria/complications , Syndrome
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