Efficacy and safety of troglitazone in the treatment of lipodystrophy syndromes

Body Fat Distribution Contributes to Defining the Relationship between Insulin Resistance and Obesity in Human Diseases

The risk for metabolic and cardiovascular complications of obesity is defined by body fat distribution rather than global adiposity. Unlike subcutaneous fat, visceral fat (including hepatic steatosis) reflects insulin resistance and predicts type 2 diabetes and cardiovascular disease. In humans, available evidence indicates that the ability to store triglycerides in the subcutaneous adipose tissue reflects enhanced insulin sensitivity. Prospective studies document an association between larger subcutaneous fat mass at baseline and reduced incidence of impaired glucose tolerance. Case-control studies reveal an association between genetic predisposition to insulin resistance and a lower amount of subcutaneous adipose tissue. Human peroxisome proliferator-activated receptorgamma (PPAR-γ) promotes subcutaneous adipocyte differentiation and subcutaneous fat deposition, improving insulin resistance and reducing visceral fat. Thiazolidinediones reproduce the effects of PPAR-γ activation and therefore increase the amount of subcutaneous fat while enhancing insulin sensitivity and reducing visceral fat. Partial or virtually complete lack of adipose tissue (lipodystrophy) is associated with insulin resistance and its clinical manifestations, including essential hypertension, hypertriglyceridemia, reduced HDL-c, type 2 diabetes, cardiovascular disease, and kidney disease. Patients with Prader Willi syndrome manifest severe subcutaneous obesity without insulin resistance. The impaired ability to accumulate fat in the subcutaneous adipose tissue may be due to deficient triglyceride synthesis, inadequate formation of lipid droplets, or defective adipocyte differentiation. Lean and obese humans develop insulin resistance when the capacity to store fat in the subcutaneous adipose tissue is exhausted and deposition of triglycerides is no longer attainable at that location. Existing adipocytes become large and reflect the presence of insulin resistance.

Inguinal Fat Compensates Whole Body Metabolic Functionality in Partially Lipodystrophic Mice with Reduced PPARγ Expression

Peroxisome proliferator-activated receptor γ (PPARγ) gene mutations in humans and mice lead to whole-body insulin resistance and partial lipodystrophy. It is unclear whether preserved fat depots in partial lipodystrophy are beneficial for whole-body metabolic homeostasis. We analyzed the insulin response and expression of metabolic genes in the preserved fat depots of PpargC/- mice, a familial partial lipodystrophy type 3 (FPLD3) mouse model resulting from a 75% decrease in Pparg transcripts. Perigonadal fat of PpargC/- mice in the basal state showed dramatic decreases in adipose tissue mass and insulin sensitivity, whereas inguinal fat showed compensatory increases. Preservation of inguinal fat metabolic ability and flexibility was reflected by the normal expression of metabolic genes in the basal or fasting/refeeding states. The high nutrient load further increased insulin sensitivity in inguinal fat, but the expression of metabolic genes became dysregulated. Inguinal fat removal resulted in further impairment of whole-body insulin sensitivity in PpargC/- mice. Conversely, the compensatory increase in insulin sensitivity of the inguinal fat in PpargC/- mice diminished as activation of PPARγ by its agonists restored insulin sensitivity and metabolic ability of perigonadal fat. Together, we demonstrated that inguinal fat of PpargC/- mice plays a compensatory role in combating perigonadal fat abnormalities.

Achievements, prospects and challenges in precision care for monogenic insulin-deficient and insulin-resistant diabetes

Integration of genomic and other data has begun to stratify type 2 diabetes in prognostically meaningful ways, but this has yet to impact on mainstream diabetes practice. The subgroup of diabetes caused by single gene defects thus provides the best example to date of the vision of 'precision diabetes'. Monogenic diabetes may be divided into primary pancreatic beta cell failure, and primary insulin resistance. In both groups, clear examples of genotype-selective responses to therapy have been advanced. The benign trajectory of diabetes due to pathogenic GCK mutations, and the sulfonylurea-hyperresponsiveness conferred by activating KCNJ11 or ABCC8 mutations, or loss-of-function HNF1A or HNF4A mutations, often decisively guide clinical management. In monogenic insulin-resistant diabetes, subcutaneous leptin therapy is beneficial in some severe lipodystrophy. Increasing evidence also supports use of 'obesity therapies' in lipodystrophic people even without obesity. In beta cell diabetes the main challenge is now implementation of the precision diabetes vision at scale. In monogenic insulin-resistant diabetes genotype-specific benefits are proven in far fewer patients to date, although further genotype-targeted therapies are being evaluated. The conceptual paradigm established by the insulin-resistant subgroup with 'adipose failure' may have a wider influence on precision therapy for common type 2 diabetes, however. For all forms of monogenic diabetes, population-wide genome sequencing is currently forcing reappraisal of the importance assigned to pathogenic mutations when gene sequencing is uncoupled from prior suspicion of monogenic diabetes.

The medicinal perspective of 2,4-thiazolidinediones based ligands as antimicrobial, antitumor and antidiabetic agents: A review

2,4-Thiazolidinedione (2,4-TZD), commonly known as glitazone, is a ubiquitous heterocyclic pharmacophore possessing a plethora of pharmacological activities and offering a vast opportunity for structural modification. The diverse range of biological activities endowed with a novel mode of action, low cost, and easy synthesis has attracted the attention of medicinal chemists. Several researchers have integrated the TZD core with different structural fragments to develop a wide range of lead molecules against various clinical disorders. The most common sites for structural modifications at the 2,4-TZD nucleus are the N-3 and the active methylene at C-5. The review covers the recent development of TZD derivatives such as antimicrobial, anticancer, and antidiabetic agents. Various 2,4-TZD based agents or drugs, which are either under clinical development or in the market, are discussed in the study. Different synthetic methodologies for synthesizing the 2,4-TZD core are also included in the manuscript. The importance of various substitutions at N-3 and C-5 and the mechanisms of action and structure-activity relationships are also discussed. We hope this study will serve as a valuable tool for the scientific community engaged in the structural exploitation of the 2,4-TZD core for developing novel drug m\olecules for life-threatening ailments.

Approach to the Patient With Lipodystrophy

Lipodystrophy constitutes a spectrum of diseases characterized by a generalized or partial absence of adipose tissue. Underscoring the role of healthy fat in maintenance of metabolic homeostasis, fat deficiency in lipodystrophy typically leads to profound metabolic disturbances including insulin resistance, hypertriglyceridemia, and ectopic fat accumulation. While rare, recent genetic studies indicate that lipodystrophy is more prevalent than has been previously thought, suggesting considerable underdiagnosis in clinical practice. In this article, we provide an overview of the etiology and management of generalized and partial lipodystrophy disorders. We bring together the latest scientific evidence and clinical guidelines and expose key gaps in knowledge. Through improved recognition of the lipodystrophy disorders, patients (and their affected family members) can be appropriately screened for cardiometabolic, noncardiometabolic, and syndromic abnormalities and undergo treatment with targeted interventions. Notably, insights gained through the study of this rare and extreme phenotype can inform our knowledge of more common disorders of adipose tissue overload, including generalized obesity.

Advances in the care of lipodystrophies

PURPOSE OF REVIEW

Lipodystrophies are a group of rare, heterogeneous disorders characterized by a lack or maldistribution of adipose tissue. Treatment focusses on the management of complications, including hypertriglyceridemia, which can be severe. Patients are predisposed to early atherosclerotic cardiovascular disease and acute pancreatitis. This review summarizes the recent advances in the treatment of lipodystrophies, with a particular focus on the treatment of hypertriglyceridemia in familial partial lipodystrophy (FPLD).

RECENT FINDINGS

Treatment of dyslipidemia in FPLD requires management of secondary exacerbating factors, particularly insulin resistance and diabetes, together with modification of atherosclerotic cardiovascular disease risk factors. In addition, specific lipid-lowering therapies are usually needed, starting with statins and fibrates. Leptin therapy improves triglycerides. Several emerging treatments for hypertriglyceridemia include apo C-III antagonists (volanesorsen, AKCEA-APOCIII-LRx and ARO-APOC3) and angiopoietin-like 3 antagonists (evinacumab, vupanorsen and ARO-ANG3); efficacy observed in clinical trials of these agents in nonlipodystrophic patients with severe hypertriglyceridemia suggests that they may also be helpful in lipodystrophy.

SUMMARY

Emerging therapies for dyslipidemia show promise in advancing the care of patients with lipodystrophy. However, these treatments are not yet approved for use in lipodystrophy. Further study of their efficacy and safety in this patient population is needed.

Role of Actionable Genes in Pursuing a True Approach of Precision Medicine in Monogenic Diabetes

Monogenic diabetes is a genetic disorder caused by one or more variations in a single gene. It encompasses a broad spectrum of heterogeneous conditions, including neonatal diabetes, maturity onset diabetes of the young (MODY) and syndromic diabetes, affecting 1-5% of patients with diabetes. Some of these variants are harbored by genes whose altered function can be tackled by specific actions ("actionable genes"). In suspected patients, molecular diagnosis allows the implementation of effective approaches of precision medicine so as to allow individual interventions aimed to prevent, mitigate or delay clinical outcomes. This review will almost exclusively concentrate on the clinical strategy that can be specifically pursued in carriers of mutations in "actionable genes", including ABCC8, KCNJ11, GCK, HNF1A, HNF4A, HNF1B, PPARG, GATA4 and GATA6. For each of them we will provide a short background on what is known about gene function and dysfunction. Then, we will discuss how the identification of their mutations in individuals with this form of diabetes, can be used in daily clinical practice to implement specific monitoring and treatments. We hope this article will help clinical diabetologists carefully consider who of their patients deserves timely genetic testing for monogenic diabetes.

Case Report: A New Peroxisome Proliferator-Activated Receptor Gamma Mutation Causes Familial Partial Lipodystrophy Type 3 in a Chinese Patient

PURPOSE

Familial partial lipodystrophy type 3 (FPLD3) is an autosomal dominant disease. Patients typically present with loss of adipose tissue and metabolic complications. Here, we reported a Chinese FPLD3 patient with a novel PPARG gene mutation.

METHODS

A 16-year-old female patient and her relatives were assessed by detailed clinical and biochemical examinations. Sequencing was performed by using the extracted DNA. Moreover, we identified FPLD3 patients from previous studies, and according to the protein region affected by the gene mutation. We divided the patients into the DNA-binding domain (DBD) group or the ligand-binding domain (LBD) group, and compared the clinical features between the two groups.

RESULTS

We identified a novel gene mutation affecting the LBD of PPARγ c.929T > C (p.F310S). This mutation leads to the substitution of a phenylalanine by a serine. In our case, subcutaneous fat was significantly diminished in her face, hips and limbs. The patient was also presented with insulin resistance, diabetes mellitus, hypertriglyceridemia, fatty liver, liver dysfunction, albuminuria and diabetic peripheral neuropathy. After literature review, a total of 58 FPLD3 patients were identified and we found no difference in clinical features between the DBD group and LBD group (all P > 0.05).

CONCLUSIONS

A Chinese FPLD3 patient with a novel PPARG gene mutation is described. Our case emphasized the importance of physical examination and genetic testing in young patients with severe metabolic syndromes.

Familial partial lipodystrophy syndromes

Lipodystrophies are a heterogeneous group of rare conditions characterised by the loss of adipose tissue. The most common forms are the familial partial lipodystrophy (FPLD) syndromes, which include a set of disorders, usually autosomal dominant, due to different pathogenetic mechanisms leading to improper fat distribution (loss of fat in the limbs and gluteal region and variable regional fat accumulation). Affected patients are prone to suffering serious morbidity via the development of metabolic complications associated to insulin resistance and an inability to properly store lipids. Although no well-defined diagnostic criteria have been established for lipodystrophy, there are certain clues related to medical history, physical examination and body composition evaluation that may suggest FPLD prior to confirmatory genetic analysis. Its treatment must be fundamentally oriented towards the control of the metabolic abnormalities. In this sense, metreleptin therapy, the newer classes of hypoglycaemic agents and other investigational drugs are showing promising results. This review aims to summarise the current knowledge of FPLD syndromes and to describe their clinical and molecular picture, diagnostic approaches and recent treatment modalities.

Laminopathies' Treatments Systematic Review: A Contribution Towards a 'Treatabolome'

BACKGROUND

Variants in the LMNA gene, encoding lamins A/C, are responsible for a growing number of diseases, all of which complying with the definition of rare diseases. LMNA-related disorders have a varied phenotypic expression with more than 15 syndromes described, belonging to five phenotypic groups: Muscular Dystrophies, Neuropathies, Cardiomyopathies, Lipodystrophies and Progeroid Syndromes. Overlapping phenotypes are also reported. Linking gene and variants with phenotypic expression, disease mechanisms, and corresponding treatments is particularly challenging in laminopathies. Treatment recommendations are limited, and very few are variant-based.

OBJECTIVE

The Treatabolome initiative aims to provide a shareable dataset of existing variant-specific treatment for rare diseases within the Solve-RD EU project. As part of this project, we gathered evidence of specific treatments for laminopathies via a systematic literature review adopting the FAIR (Findable, Accessible, Interoperable, and Reusable) guidelines for scientific data production.

METHODS

Treatments for LMNA-related conditions were systematically collected from MEDLINE and Embase bibliographic databases and clinical trial registries (Cochrane Central Registry of Controlled Trials, clinicaltrial.gov and EudraCT). Two investigators extracted and analyzed the literature data independently. The included papers were assessed using the Oxford Centre for Evidence-Based Medicine 2011 Levels of Evidence.

RESULTS

From the 4783 selected articles by a systematic approach, we identified 78 papers for our final analysis that corresponded to the profile of data defined in the inclusion and exclusion criteria. These papers include 2 guidelines/consensus papers, 4 meta-analyses, 14 single-arm trials, 15 case series, 13 cohort studies, 21 case reports, 8 expert reviews and 1 expert opinion. The treatments were summarized electronically according to significant phenome-genome associations. The specificity of treatments according to the different laminopathic phenotypical presentations is variable.

CONCLUSIONS

We have extracted Treatabolome-worthy treatment recommendations for patients with different forms of laminopathies based on significant phenome-genome parings. This dataset will be available on the Treatabolome website and, through interoperability, on genetic diagnosis and treatment support tools like the RD-Connect's Genome Phenome Analysis Platform.

Fermented mulberry (Morus alba) leaves suppress high fat diet-induced hepatic steatosis through amelioration of the inflammatory response and autophagy pathway

BACKGROUND

A novel extract of mulberry leaves fermented with Cordyceps militaris (EMfC) is reported to exert anti-obesity activity, although their molecular mechanism during hepatic steatosis has not verified.

METHODS

To investigate the role of inflammation and autophagy during the anti-hepatic steatosis effects of EMfC, we measured alterations in the key parameters for inflammatory response and autophagy pathway in liver tissues of the high fat diet (HFD) treated C57BL/6N mice after exposure to EMfC for 12 weeks.

RESULTS

Significant anti-hepatic steatosis effects, including decreased number of lipid droplets and expression of Klf2 mRNA, were detected in the liver of the HFD + EMfC treated group. The levels of mast cell infiltration, expression of two inflammatory mediators (iNOS and COX-2), and the MAPK signaling pathway were remarkably decreased in the liver of HFD + EMfC treated group as compared to the HFD + Vehicle treated group. Furthermore, a similar inhibitory effect was measured for the expression levels of pro-inflammatory cytokines, including IL-1β, IL-6, TNF-α and NF-κB. The expression level of members in the AKT/mTOR signaling pathway (a central regulator in autophagy) was recovered after treatment with EMfC, and autophagy-related proteins (Beclin and LC3-II) were remarkably decreased in the HFD + EMfC treated group compared to the HFD + Vehicle treated group. Moreover, the HFD + EMfC treated group showed decreased transcript levels of autophagy-regulated genes including Atg4b, Atg5, Atg7 and Atg12.

CONCLUSIONS

Taken together, findings of the present study provide novel evidences that the anti-hepatic steatosis of EMfC is tightly linked to the regulation of the inflammatory response and autophagy pathway in the liver tissue of HFD-induced obesity mice.

Rnf20 deficiency in adipocyte impairs adipose tissue development and thermogenesis

RNF20, an E3 ligase critical for monoubiquitination of histone H2B at lysine 120 (H2Bub), has been implicated in the regulation of various cellar processes; however, its physiological roles in adipocytes remain poorly characterized. Here, we report that the adipocyte-specific knockout of Rnf20 (ASKO) in mice led to progressive fat loss, organomegaly and hyperinsulinemia. Despite signs of hyperinsulinemia, normal insulin sensitivity and improved glucose tolerance were observed in the young and aged CD-fed ASKO mice. In addition, high-fat diet-fed ASKO mice developed severe liver steatosis. Moreover, we observed that the ASKO mice were extremely sensitive to a cold environment due to decreased expression levels of brown adipose tissue (BAT) selective genes, including uncoupling protein 1 (Ucp1), and impaired mitochondrial functions. Significantly decreased levels of peroxisome proliferator-activated receptor gamma (Pparγ) were observed in the gonadal white adipose tissues (gWAT) from the ASKO mice, suggesting that Rnf20 regulates adipogenesis, at least in part, through Pparγ. Rosiglitazone-treated ASKO mice exhibited increased fat mass compared to that of the non-treated ASKO mice. Collectively, our results illustrate the critical role of RNF20 in control of white and brown adipose tissue development and physiological function.

Familial Partial Lipodystrophy (FPLD): Recent Insights

Lipodystrophies are a heterogeneous group of congenital or acquired disorders, characterized by partial or generalized loss of adipose tissue. Familial partial lipodystrophy (FPLD) presents with genetic and phenotypic variability with insulin resistance, hypertriglyceridemia and hepatic steatosis being the cardinal metabolic features. The severity of the metabolic derangements is in proportion with the degree of lipoatrophy. The underpinning pathogenetic mechanism is the limited capacity of adipose tissue to store lipids leading to lipotoxicity, low-grade inflammation, altered adipokine secretion and ectopic fat tissue accumulation. Advances in molecular genetics have led to the discovery of new genes and improved our knowledge of the regulation of adipose tissue biology. Diagnosis relies predominantly on clinical findings, such as abnormal fat tissue topography and signs of insulin resistance and is confirmed by genetic analysis. In addition to anthropometry and conventional imaging, new techniques such as color-coded imaging of fat depots allow more accurate assessment of the regional fat distribution and differentiation of lipodystrophic syndromes from common metabolic syndrome phenotype. The treatment of patients with lipodystrophy has proven to be challenging. The use of a human leptin analogue, metreleptin, has recently been approved in the management of FPLD with evidence suggesting improved metabolic profile, satiety, reproductive function and self-perception. Preliminary data on the use of glucagon-like peptide 1 receptor agonists (GLP1 Ras) and sodium-glucose co-transporter 2 (SGLT2) inhibitors in cases of FPLD have shown promising results with reduction in total insulin requirements and improvement in glycemic control. Finally, investigational trials for new therapeutic agents in the management of FPLD are underway.

Adipogenesis and metabolic health

Obesity is characterized by increased adipose tissue mass and has been associated with a strong predisposition towards metabolic diseases and cancer. Thus, it constitutes a public health issue of major proportion. The expansion of adipose depots can be driven either by the increase in adipocyte size (hypertrophy) or by the formation of new adipocytes from precursor differentiation in the process of adipogenesis (hyperplasia). Notably, adipocyte expansion through adipogenesis can offset the negative metabolic effects of obesity, and the mechanisms and regulators of this adaptive process are now emerging. Over the past several years, we have learned a considerable amount about how adipocyte fate is determined and how adipogenesis is regulated by signalling and systemic factors. We have also gained appreciation that the adipogenic niche can influence tissue adipogenic capability. Approaches aimed at increasing adipogenesis over adipocyte hypertrophy can now be explored as a means to treat metabolic diseases.

Fatty liver in lipodystrophy: A review with a focus on therapeutic perspectives of adiponectin and/or leptin replacement

Lipodystrophy is a group of clinically heterogeneous, inherited or acquired, disorders characterized by complete or partial absence of subcutaneous adipose tissue that may occur simultaneously with the pathological, ectopic, accumulation of fat in other regions of the body, including the liver. Fatty liver adds significantly to hepatic and extra-hepatic morbidity in patients with lipodystrophy. Lipodystrophy is strongly associated with severe insulin resistance and related comorbidities, such as hyperglycemia, hyperlipidemia and nonalcoholic fatty liver disease (NAFLD), but other hepatic diseases may co-exist in some types of lipodystrophy, including autoimmune hepatitis in acquired lipodystrophies, or viral hepatitis in human immunodeficiency virus (HIV)-associated lipodystrophy. The aim of this review is to summarize evidence linking lipodystrophy with hepatic disease and to provide a special focus on potential therapeutic perspectives of leptin replacement therapy and adiponectin upregulation in lipodystrophy.

Update on Therapeutic Options in Lipodystrophy

PURPOSE OF REVIEW

The purpose of this review is to summarize the therapeutic approach for lipodystrophy syndromes with conventional treatment options and metreleptin therapy in detail and to point out the current investigational treatments in development.

RECENT FINDINGS

The observation of leptin deficiency in patients with lipodystrophy and the potential of leptin replacement to rescue metabolic abnormalities in animal models of lipodystrophy were followed by the first clinical study of leptin therapy in patients with severe lipodystrophy. This and several other long-term studies demonstrated important benefits of recombinant human leptin (metreleptin) to treat metabolic abnormalities of lipodystrophy. These studies ultimately led to the recent FDA approval of metreleptin for the treatment of generalized lipodystrophy and EMA approval for both generalized and partial lipodystrophy. Additional research efforts in progress focus on novel treatment options, predominantly for patients with partial lipodystrophy. Current treatment of generalized lipodystrophy includes metreleptin replacement as an adjunct to diet and standard treatment approach for metabolic consequences of lipodystrophy. Beyond metreleptin, a number of different compounds and treatment modalities are being studied for the treatment of partial lipodystrophy.

Clinical Characteristics, Phenotype of Lipodystrophy and a Genetic Analysis of Six Diabetic Japanese Women with Familial Partial Lipodystrophy in a Diabetic Outpatient Clinic

Objective Our aim was to examine the clinical characteristics and phenotype of lipodystrophy of six diabetic Japanese women with partial lipodystrophy (PL) who received a genetic analysis at a diabetic outpatient clinic. Methods We screened for PL using dual energy X-ray absorptiometry (DEXA) and magnetic resonance imaging (MRI) among patients who had a reduced peripheral skinfold thickness at the diabetic outpatient clinic of Kusatsu General Hospital between August 2003 and August 2013. We performed a mutation analysis of candidate genes, including LMNA and PPARG, in two patients with PL and whole-exome sequencing in four patients with PL. Results We identified 15 patients with PL and performed a genetic analysis in 6 of them. They had no mutations in candidate genes known to be associated with familial partial lipodystrophy (FPLD). They all had near-complete loss of subcutaneous fat, particularly in the antero-lateral and posterior thigh region and the calf region. As almost all patients were characterized by fat loss in the lower limbs with abdominal fat accumulation, a high rate of positivity for a family history, diabetes, and an unknown genetic cause, we suspected they might have FPLD1. Some patients have shown relatively severe insulin resistance, while others have shown insulin deficiency. Four and one had severe atherosclerosis and liver cirrhosis, probably due to nonalcoholic steatohepatitis, respectively. Conclusion Almost all patients with PL identified in a diabetic outpatient clinic had subcutaneous fat loss in the lower limbs with excess truncal fat and might have had FPLD1.

Prediction of Cardiovascular Disease Risk Using Framingham and Data on Adverse Effect of Antiretroviral Drugs Risk Equation in Relation to Lipodystrophy in HIV Patients on Highly Active Antiretroviral Therapy

Background:

In the era of high active antiretroviral therapy (HAART), with increasing survival of HIV patients, cardiovascular risk has emerged as a leading health issue.

Aims:

This study aims to predict the 10-year cardiovascular disease risk in HIV patients using the Framingham risk score and its modification for HIV-infected patients on HAART, that is, the data on adverse effect of antiretroviral drugs (DAD) prediction equation.

Setting and Design:

This is a case control study.

Materials and Methods:

The present study included 320 subjects (220 HIV infected cases and 100 age, sex and body mass index matched HIV noninfected healthy controls) and was conducted in a tertiary care centre in western Rajasthan. All the patients were subjected to a detailed clinical history, complete physical examination and evaluation of laboratory parameters. We calculated Framingham risk score and DAD prediction equation for these patients and compared these scores between patients on HAART with lipodystrophy, those without lipodystrophy, HAART naive and healthy controls.

Statistical Analysis:

Unpaired t-test was used and statistical analysis was performed using SPSS version 20.

Results:

In our study, 46.67% patients on HAART developed lipodystrophy, of which 17.72% had moderate-to-high risk of cardiovascular risk according to Framingham risk score, which is significantly higher than in patients without lipodystrophy and controls (3.3% and 6%, respectively). Similar high risk was also seen with DAD score. The various risk factors also showed a positive correlation with duration of HAART.

Conclusion:

Our study emphasizes the need for early recognition of cardiovascular risk in HIV-infected patients on HAART, especially in those with lipodystrophy and advocates effective use of risk calculators in these patients.

[A complex case of diabetes due to LMNA mutation]

INTRODUCTION

Laminopathies (diseases related to A/C mutations of lamines) are rare genetic diseases with an extensive phenotypic spectrum, including lipodystrophic syndromes-characterized by a selective loss of adipose tissue-of which the partial Dunnigan family type is the most frequent.

CASE REPORT

We report on a 55-year-old woman with diabetes and long-term disabling myalgia. Her cushingoid morphotype, associated with cutaneous lipo-atrophy and muscle hypertrophy in addition to a genetic heritage, led us to the diagnosis of complex partial familial lipodystrophy heterozygous LMNA_c.82C>T, p.Arg28Trp mutation.

CONCLUSION

Familial partial lipodystrophic syndromes may have varied phenotypes, mainly cardio-metabolic, which could mimic a particularly severe type 2 diabetes. The diagnostic work-up of this disease has to include a careful investigation of gait troubles and paroxysmal conduction that could lead to sudden death, as well as a genetic examination. In some cases, recombinant leptin can be proposed.

The Diagnosis and Management of Lipodystrophy Syndromes: A Multi-Society Practice Guideline

OBJECTIVE

Lipodystrophy syndromes are extremely rare disorders of deficient body fat associated with potentially serious metabolic complications, including diabetes, hypertriglyceridemia, and steatohepatitis. Due to their rarity, most clinicians are not familiar with their diagnosis and management. This practice guideline summarizes the diagnosis and management of lipodystrophy syndromes not associated with HIV or injectable drugs.

PARTICIPANTS

Seventeen participants were nominated by worldwide endocrine societies or selected by the committee as content experts. Funding was via an unrestricted educational grant from Astra Zeneca to the Pediatric Endocrine Society. Meetings were not open to the general public.

EVIDENCE

A literature review was conducted by the committee. Recommendations of the committee were graded using the system of the American Heart Association. Expert opinion was used when published data were unavailable or scarce.

CONSENSUS PROCESS

The guideline was drafted by committee members and reviewed, revised, and approved by the entire committee during group meetings. Contributing societies reviewed the document and provided approval.

CONCLUSIONS

Lipodystrophy syndromes are heterogeneous and are diagnosed by clinical phenotype, supplemented by genetic testing in certain forms. Patients with most lipodystrophy syndromes should be screened for diabetes, dyslipidemia, and liver, kidney, and heart disease annually. Diet is essential for the management of metabolic complications of lipodystrophy. Metreleptin therapy is effective for metabolic complications in hypoleptinemic patients with generalized lipodystrophy and selected patients with partial lipodystrophy. Other treatments not specific for lipodystrophy may be helpful as well (eg, metformin for diabetes, and statins or fibrates for hyperlipidemia). Oral estrogens are contraindicated.

Mechanisms by which the thiazolidinedione troglitazone protects against sucrose-induced hepatic fat accumulation and hyperinsulinaemia

BACKGROUND AND PURPOSE

Thiazolidinediones (TZD) are known to ameliorate fatty liver in type 2 diabetes. To date, the underlying mechanisms of their hepatic actions remain unclear.

EXPERIMENTAL APPROACH

Hepatic triglyceride content and export rates were assessed in 2 week high-sucrose-fed Wistar rats treated with troglitazone and compared with untreated high-sucrose rodent controls. Fractional de novo lipogenesis (DNL) contributions to hepatic triglyceride were quantified by analysis of triglyceride enrichment from deuterated water. Hepatic insulin clearance and NO status during a meal tolerance test were also evaluated.

KEY RESULTS

TZD significantly reduced hepatic triglyceride (P < 0.01) by 48%, decreased DNL contribution to hepatic triglyceride (P < 0.01) and increased postprandial non-esterified fatty acids clearance rates (P < 0.01) in comparison with the high-sucrose rodent control group. During a meal tolerance test, plasma insulin AUC was significantly lower (P < 0.01), while blood glucose and plasma C-peptide levels were not different. Insulin clearance was increased (P < 0.001) by 24% and was associated with a 22% augmentation of hepatic insulin-degrading enzyme activity (P < 0.05). Finally, hepatic NO was decreased by 24% (P < 0.05).

CONCLUSIONS

Overall, TZD show direct actions on liver by reducing hepatic DNL and increasing hepatic insulin clearance. The alterations in hepatic insulin clearance were associated with changes in insulin-degrading enzyme activity, with possible modulation of NO levels.

A case of familial partial lipodystrophy caused by a novel lamin A/C (LMNA) mutation in exon 1 (D47N)

BACKGROUND

Familial partial lipodystrophy (FPL) is a rare genetic disorder characterized by selective lack of subcutaneous fat which is associated with insulin resistant diabetes. The Dunnigan variety (FPL2) is caused by several missense mutations in the lamin A/C (LMNA) gene, most of which are typically located in exon 8 at the codon position 482.

CASE REPORT

Here, we report on a Turkish family with FPL2 which is caused by a novel heterozygous missense LMNA mutation in exon 1 (D47N, c.139G>A), in the rod domain of lamins A/C. Fat distribution and metabolic features of LMNA D47N mutation were similar to typical codon 482 mutation. Metabolic abnormalities were observed as a form of insulin resistant diabetes, hypertriglyceridemia, low HDL cholesterol and hepatic steatosis. There was no evidence for neuromuscular and cardiac involvement.

CONCLUSION

Although it is previously known that alterations in the rod domain of type A lamins are involved in cardiac and neuromuscular diseases, our current observation shows that exon 1 LMNA mutations may be associated with partial lipodystrophy without any cardiac and neurological abnormalities, at least at the time of the presentation.

Metreleptin and generalized lipodystrophy and evolving therapeutic perspectives

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.

Metreleptin for injection to treat the complications of leptin deficiency in patients with congenital or acquired generalized lipodystrophy

The lipodystrophies represent a class of diseases characterized by leptin deficiency. Leptin deficiency is associated with a severe form of the metabolic syndrome characterized by dyslipidemia, insulin resistance, diabetes, and ovarian dysfunction. Metreleptin is the pharmaceutical derived product that has been approved by the Food and Drug Administration (FDA) to treat the severe metabolic abnormalities of the generalized forms of lipodystrophy. Herein we describe the properties of metreleptin, its use in patients, which includes the administration of the drug and how it may be acquired by medical professionals as well as its safety, tolerability, and properties. Finally, we speculate on future uses and development of metreleptin.

Congenital lipodystrophies and dyslipidemias

Lipodystrophies are rare acquired and genetic disorders characterized by the selective loss of adipose tissue. One key metabolic feature of patients with congenital inherited lipodystrophy is hypertriglyceridemia. The precise mechanisms by which the lack of adipose tissue causes dyslipidemia remain largely unknown. In recent years, new insights have arisen from data obtained in vitro in adipocytes, yeast, drosophila, and very recently in several genetically modified mouse models of generalized lipodystrophy. A common metabolic pathway involving accelerated lipolysis and defective energy storage seems to contribute to the dyslipidemia associated with congenital generalized lipodystrophy syndromes, although the pathophysiological changes may vary with the nature of the mutation involved. Therapeutic management of dyslipidemia in patients with lipodystrophy is primarily based on specific approaches using recombinant leptin therapy. Preclinical studies suggest a potential efficacy of thiazolidinediones that remains to be assessed in dedicated clinical trials.

Adipose-specific knockout of SEIPIN/BSCL2 results in progressive lipodystrophy

Berardinelli-Seip congenital lipodystrophy type 2 (BSCL2) is the most severe form of human lipodystrophy, characterized by an almost complete loss of adipose tissue and severe insulin resistance. BSCL2 is caused by loss-of-function mutations in the BSCL2/SEIPIN gene, which is upregulated during adipogenesis and abundantly expressed in the adipose tissue. The physiological function of SEIPIN in mature adipocytes, however, remains to be elucidated. Here, we generated adipose-specific Seipin knockout (ASKO) mice, which exhibit adipocyte hypertrophy with enlarged lipid droplets, reduced lipolysis, adipose tissue inflammation, progressive loss of white and brown adipose tissue, insulin resistance, and hepatic steatosis. Lipidomic and microarray analyses revealed accumulation/imbalance of lipid species, including ceramides, in ASKO adipose tissue as well as increased endoplasmic reticulum stress. Interestingly, the ASKO mice almost completely phenocopy the fat-specific peroxisome proliferator-activated receptor-γ (Pparγ) knockout (FKO-γ) mice. Rosiglitazone treatment significantly improved a number of metabolic parameters of the ASKO mice, including insulin sensitivity. Our results therefore demonstrate a critical role of SEIPIN in maintaining lipid homeostasis and function of adipocytes and reveal an intimate relationship between SEIPIN and PPAR-γ.

Primary intestinal follicular lymphoma and premature atherosclerosis in a Japanese diabetic patient with atypical familial partial lipodystrophy

We experienced a case of primary intestinal follicular lymphoma and premature atherosclerosis in a diabetic patient with familial partial lipodystrophy (FPL) that was detected when the patient was evaluated for laparoscopic sleeve gastrectomy (LSG). As FPL is generally considered to be rare, FPL is often underdiagnosed, especially in obese patients. Therefore, the prevalence of FPL is higher than previous estimates. Our case illustrates that clinicians should perform screening for atherosclerosis and malignancy at the preoperative evaluation and may need to perform metabolic surgery earlier to prevent the development of excess truncal fat, complicated diabetes and atherosclerosis in patients with FPL.

Adipose tissue depot and cell size dependency of adiponectin synthesis and secretion in human obesity

Adiponectin is an insulin sensitizing fat cell (FC) hormone whose levels are related to adipose tissue (AT) mass and depot distribution. We hypothesized that the nature of AT expansion (hypertrophy vs. hyperplasia) contributes to obesity-related reductions in serum adiponectin and that this effect is influenced by the regional distribution of AT to subcutaneous (S) and visceral (V) depots. Thirteen obese subjects provided paired AT biopsies. Serum total and high molecular weight (HMW) adiponectin levels were determined by ELISA. Secretion was quantified following 24-h explant culture. FC size, number, % large, and % small FC were determined by microscopic analysis. Secretion of total adiponectin was highest by SAT (P = 0.008) and correlated more strongly with serum adiponectin (total: P = 0.015, r = 0.77; HMW: P = 0.005, r = 0.83) than did secretion by VAT (P = 0.05, r = 0.66 for both). FC size was greatest in SAT and correlated negatively with both serum (total: P = 0.01, r = −0.74; HMW: P = 0.03, r = −0.69) and secreted (total: P = 0.05, r = −0.72; HMW: P = 0.02, r = −0.87) adiponectin. The % small FC in SAT correlated positively with both serum (total: P = 0.006, r = 0.87; HMW: P = 0.009, r = 0.79) and secreted (total: P = 0.03, r = 0.75; HMW: P = 0.01, r = 0.92) adiponectin. VAT FC size correlated negatively with serum HMW adiponectin (P = 0.01, r = −0.76) but not with any measure of secretion. VAT had the greatest % small FC, which related positively to serum HMW (P = 0.004, r = 0.81) and to secreted total adiponectin (P = 0.02, r = 0.78). These studies indicate that differences in fat cell size and depot distribution of AT expansion are important influences on adiponectin in obesity.

Current treatment methods for combination antiretroviral therapy-induced lipoatrophy of the face

Summary

Combination antiretroviral therapy (CART) reduces the mortality and morbidity in HIV-infected patients. However, facial lipoatrophy (FLA) is one of the well-known side-effects of this treatment and subsequently imposes major problems for HIV-infected patients. In the last decade, ample experience has been obtained with both local therapeutic options as well as possible systemic treatment options. Soft tissue fillers are a relatively simple and efficient treatment option for FLA. Especially, the biodegradable semi-permanent fillers combine a good effect with durability and an acceptable safety profile. The best way to prevent or restrict the development of FLA remains the exclusion of thymidine analogue nucleoside reverse-transcriptase inhibitors from the CART schedule.

Regional anthropometric measures associated with the severity of liver injury in patients with non-alcoholic fatty liver disease

BACKGROUND

Not all NAFLD patients are obese and many obese patients do not have NAFLD. Impaired peripheral fat storage may increase the delivery of lipids to the liver and facilitate NAFLD progression.

AIM

To assess the association of anthropometric measures of regional adiposity including arm fat index (AFI) (upper body fat), waist circumference (visceral fat) and body mass index (total body fat) on liver injury and fibrosis in NAFLD.

METHODS

One hundred and forty-one patients with histological evidence of NAFLD were included in this study. Multivariate logistic regression models examined the contribution of age, sex, body mass index, AFI, triceps fold thickness (TST), waist and hip circumference to the odds of liver injury (NAS scores ≥3) and fibrosis (fibrosis scores ≥2) by liver biopsy.

RESULTS

Arm fat index (OR: 0.82, 95% CI: 0.59-0.91) and TST (OR: 0.13, 95% CI: 0.04-0.42) were negatively correlated with NAFLD histological severity. In women, waist circumference was positively correlated with NAFLD severity (OR: 1.21(1.02-1.44). Age (OR: 1.05, 95% CI: 1.01-1.0) and waist circumference (OR: 1.07, 95% CI: 1.00-1.15) were significantly associated with fibrosis risk. In women, AFI (OR: 0.87, 95% CI: 0.76-0.99) and TST (OR: 0.22, 95% CI: 0.05-0.95) were negatively associated with fibrosis risk.

CONCLUSIONS

Regional anthropometric measures are associated with severity of NAFLD in a sex-specific manner. Men and women with lower arm fat depots and women with bigger waist circumference have a greater likelihood of liver injury. Age and waist circumference seem to be associated with liver fibrosis. Simple anthropometric measurements of peripheral fat deposits may help stratify significant liver injury risk.

Alterations in lipid signaling underlie lipodystrophy secondary to AGPAT2 mutations

Congenital generalized lipodystrophy (CGL), secondary to AGPAT2 mutation is characterized by the absence of adipocytes and development of severe insulin resistance. In the current study, we investigated the adipogenic defect associated with AGPAT2 mutations. Adipogenesis was studied in muscle-derived multipotent cells (MDMCs) isolated from vastus lateralis biopsies obtained from controls and subjects harboring AGPAT2 mutations and in 3T3-L1 preadipocytes after knockdown or overexpression of AGPAT2. We demonstrate an adipogenic defect using MDMCs from control and CGL human subjects with mutated AGPAT2. This defect was rescued in CGL MDMCs with a retrovirus expressing AGPAT2. Both CGL-derived MDMCs and 3T3-L1 cells with knockdown of AGPAT2 demonstrated an increase in cell death after induction of adipogenesis. Lack of AGPAT2 activity reduces Akt activation, and overexpression of constitutively active Akt can partially restore lipogenesis. AGPAT2 modulated the levels of phosphatidic acid, lysophosphatidic acid, phosphatidylinositol species, as well as the peroxisome proliferator-activated receptor γ (PPARγ) inhibitor cyclic phosphatidic acid. The PPARγ agonist pioglitazone partially rescued the adipogenic defect in CGL cells. We conclude that AGPAT2 regulates adipogenesis through the modulation of the lipome, altering normal activation of phosphatidylinositol 3-kinase (PI3K)/Akt and PPARγ pathways in the early stages of adipogenesis.

Pathophysiology of the HIV-Associated Lipodystrophy Syndrome

The widespread use of highly active antiretroviral therapy (HAART) has radically transformed the prognosis of HIV-infected patients in the developed countries. Unfortunately, a serious metabolic syndrome combining peripheral lipoatrohy, central adiposity, insulin resistance, and dyslipidemia has arisen in these individuals. The etiology of this heterogeneous syndrome named lipodystrophy syndrome (LDS) is multifactorial, but adipose tissue is very likely a key factor that contributes to several clinical or metabolic aspects of the syndrome. In peripheral adipose tissue, HAART may act on both preadipocytes and adipocytes to induce fat loss. Several components of the HAART regimen can inhibit preadipocyte differentiation, in particular through alterations in the expression and/or function of the transcription factor sterol responsive element binding protein-1c. In superficial mature adipocytes, HAART promotes insulin resistance and apoptosis. Insulin resistance of peripheral fat cells could be the consequence of increased lipolysis and adipocytokine dysregulation. In turn, the increased free fatty acid disposal and the disturbances in adipocytokine production may induce skeletal muscle and liver insulin resistance, dyslipidemia, and a fat redistribution toward deep depots, causing visceral lipohypertrophy. The metabolic profile observed in LDS is reminiscent of that observed in metabolic syndrome, raising potential implications for cardiovascular risk in these patients. The pathophysiological mechanisms at the basis of this syndrome represent a rational basis for the treatment or prevention of the metabolic complications.

[Diabetes mellitus: clinical presentation and differential diagnosis of hyperglycemia in childhood and adolescence]

Diabetes mellitus is one of the most common chronic diseases in childhood. Despite being a clinical and etiopathogenically heterogeneous disorder, type 1 autoimmune diabetes accounts for more than 95% of cases in children. Recent advances have meant that a growing number of patients have been assigned to other subtypes of diabetes. In such cases, the correct diagnosis is facilitated by the fact that many of these rare causes of diabetes are associated with specific clinical syndromes or may present at a certain age. Many of them are also subsidiaries of molecular diagnosis. The aim of this review is to update the current knowledge in this field of pediatric diabetes, in an attempt to determine the most accurate diagnosis and its implications on appropriate treatment and prognosis.

Seipin: from human disease to molecular mechanism

The most-severe form of congenital generalized lipodystrophy (CGL) is caused by mutations in BSCL2/seipin. Seipin is a homo-oligomeric integral membrane protein in the endoplasmic reticulum that concentrates at junctions with cytoplasmic lipid droplets (LDs). While null mutations in seipin are responsible for lipodystrophy, dominant mutations cause peripheral neuropathy and other nervous system pathologies. We first review the clinical aspects of CGL and the discovery of the responsible genetic loci. The structure of seipin, its normal isoforms, and mutations found in patients are then presented. While the function of seipin is not clear, seipin gene manipulation in yeast, flies, mice, and human cells has recently yielded a trove of information that suggests roles in lipid metabolism and LD assembly and maintenance. A model is presented that attempts to bridge these new data to understand the role of this fascinating protein.

Premature atherosclerosis in a Japanese diabetic patient with atypical familial partial lipodystrophy and hypertriglyceridemia

We herein report a case of premature atherosclerosis in a patient with familial partial lipodystrophy (FPL), diabetes mellitus, hypertension and hypertriglyceridemia. Sequencing of the candidate genes LMNA, PPARG and CAV1 associated with FPL revealed no genetic abnormalities, which indicated the activity of a novel gene in this patient. The patient's son showed milder fat loss and similar fat distribution compared to the proband; however, the son showed no signs of any atherosclerotic disease. Although a cluster of atherogenic risk factors is likely to be the primary causes of atherosclerosis in our patient, other factors, including an unknown gene associated with FPL, the severity of fat loss and gender, might affect the development of atherosclerosis.

Management of the metabolic effects of HIV and HIV drugs

Morphologic and metabolic abnormalities, including subcutaneous adipose tissue wasting, central adipose tissue accumulation, dyslipidemia and disorders of glucose metabolism are common among HIV-infected patients receiving highly active antiretroviral therapy (HAART) and contribute to the risk of cardiovascular disease in this population. The pathogenesis of these disorders is due to complicated interactions between effects of chronic HIV infection, HAART medications and patient factors, including genetic susceptibility. HAART has transformed HIV into a chronic condition for many patients and as a result the majority of HIV-infected patients in many areas of the developed world will soon be aged ≥50 years. Given that metabolic and cardiovascular diseases increase with aging, knowledge of the optimal management of these conditions is essential for practitioners caring for HIV-infected patients, including endocrine subspecialists. This Review highlights the clinical management of these disorders, focusing on the latest evidence regarding the efficacy of treatment strategies, newly available medications and potential interactions between HAART medications and medications used to treat metabolic disorders.

The prevalence and pathogenesis of diabetes mellitus in treated HIV-infection

HIV-associated morbidity and mortality have declined significantly since the introduction of highly active antiretroviral therapy (HAART). These developments have allowed an increased focus on associated adverse metabolic effects, such as dyslipidemia, diabetes mellitus, and insulin resistance, which are risk factors for cardiovascular disease and other adverse outcomes. The pathophysiologic mechanisms underlying the metabolic changes are complicated and not yet fully elucidated due to the difficulty of separating the effects of HIV infection from those of HAART, co-morbidities, or individual patient vulnerabilities. This article reviews studies concerning the prevalence and incidence of diabetes mellitus and HIV, HIV-specific effects on diabetes mellitus complications, and HIV-specific diabetes mellitus treatment considerations.

The safety of thiazolidinediones

INTRODUCTION

The prevalence of type 2 diabetes mellitus (T2DM) has reached epidemic proportions. Many new therapies have emerged, including thiazolidinediones (TZDs), selective agonists of PPAR-γ, now used as both primary and add-on therapies. Given that T2DM is a lifetime disease, there is a need for assurance that new drugs are both safe and effective. Recent concern about the cardiovascular safety of one of the new drugs, rosiglitazone, is the stimulus for this review.

AREAS COVERED

The safety of pioglitazone and rosiglitazone under the headings of liver safety, cardiovascular safety, fluid retention, weight gain and bone fractures is reviewed based on a PubMed search of the years 1997 through June 2010. This review also describes the magnitude of the risks of the TZDs and provides a recommendation on the use of TZDs.

EXPERT OPINION

Liver safety is no longer an issue with the TZDs. There are no significant differences between rosiglitazone and pioglitazone in fluid retention, weight gain and bone fractures. However, pioglitazone tends to be cardioprotective while rosiglitazone is cardiotoxic. There is no current justification for prescribing rosiglitazone.

From old to new nucleoside reverse transcriptase inhibitors: changes in body fat composition, metabolic parameters and mitochondrial toxicity after the switch from thymidine analogs to tenofovir or abacavir

INTRODUCTION

Thymidine analogs zidovudine (AZT) and stavudine (d4T) have been widely used because of their antiviral activity against HIV, but at the expense of high toxicity, mainly related to mitochondrial damage. Many studies have been performed replacing AZT or d4T with newer nucleoside analogs reverse transcriptase inhibitors (NRTIs) with less toxicity, such as tenofovir (TDF) or abacavir (ABC), maintaining virological efficacy.

AREAS COVERED

Relevant literature was identified using a PubMed search of articles published up to June 2010. Search terms included: 'thymidine analogs', 'stavudine', 'zidovudine', 'd4T', 'AZT', 'ZDV', 'treatment switch'. Original articles in which d4T or AZT had been replaced by TDF or ABC as switch strategies (with undetectable viral load) were reviewed where information about body fat distribution, mitochondrial functionality and/or plasma lipid parameters were available. Relevant references from these articles were also considered. Only studies performed in adult patients (18 years or older) are included. The readers will gain a better understanding of the toxicity caused by thymidine analogs, the treatment alternatives and the benefits observed after treatment switch to newer NRTIs.

EXPERT OPINION

Thymidine analogs AZT and d4T yield considerable toxicity and proactive switch to newer NRTIs such as TDF or ABC is necessary in order to avoid or partially reverse such side effects.

Reduced adipogenic gene expression in fibroblasts from a patient with type 2 congenital generalized lipodystrophy

AIMS

Beradinelli-Seip congenital generalized lipodystrophy is a rare autosomal recessive disorder characterized by near-complete absence of adipose tissue, Herculean appearance, insulin resistance, hypoleptinaemia and diabetes mellitus. The aim of this study was to investigate the in vitro effects of pioglitazone on the expression of genes involved in adipogenesis in fibroblasts from a patient with this condition due to a seipin mutation.

METHODS

Primary cultures of fibroblasts from the skin of the patient were obtained. Fibroblasts were treated with classic adipose differentiation medium, with and without pioglitazone. Several adipogenes were evaluated by real-time reverse transcriptase-polymerase chain reaction and western blotting. Intracellular localization of prelamin A was studied by immunofluorescence microscopy.

RESULTS

The expression of the adipogenic genes PPARG, LPL, LEP and SLC2A4 was reduced in lipodystrophic fibroblasts, while treatment with pioglitazone increased the expression of these genes. Moreover, and unexpectedly, we found an accumulation of farnesylated prelamin A in lipodystrophic fibroblasts.

CONCLUSIONS

The process of adipocyte differentiation is compromised in patients with Beradinelli-Seip congenital lipodystrophy owing to diminished expression of the regulatory genes involved, which pioglitazone treatment partially rescues. Prelamin A accumulation establishes a link with other types of familial lipodystrophies, as familial partial lipodystrophy.

Clinical classification and treatment of congenital and acquired lipodystrophy

OBJECTIVE

To review the initial clinical manifestations of congenital and acquired lipodystrophy syndromes, discuss novel classifications associated with genetic mutations, and assess currently available therapeutic options for patients with lipodystrophy.

METHODS

This review is the result of the authors' collective clinical experience and a comprehensive MEDLINE literature search on the English-language literature published between January 1966 and October 2009 on "lipodystrophy." This review focuses primarily on severe dystrophy not related to human immunodeficiency virus (HIV) infection, in light of the additional scope required to cover HIV-related lipodystrophy.

RESULTS

Congenital lipodystrophy syndromes are characterized by a paucity of adipose tissue and classified on the basis of the extent of fat loss and heritability Paradoxically, they are associated with metabolic abnormalities often found in obese patients, including insulin resistance, diabetes, and severe hypertriglyceridemia. Patients with severe forms of lipodystrophy are also deficient in adipokines such as leptin, which may contribute to metabolic abnormalities. The search for molecular defects has revealed a role for genes that affect adipocyte differentiation (for example, peroxisome proliferator-activated receptor gamma), lipid droplet morphology (seipin, caveolin-1), or lipid metabolism (AGPAT2). Others (lamin A/C) are known to be associated with completely different diseases. There are also acquired forms of lipodystrophy that are thought to occur primarily attributable to autoimmune mechanisms. Recently, recombinant leptin has emerged as a useful therapy.

CONCLUSION

Lipodystrophy syndromes have advanced our understanding of the physiologic role of adipose tissue and allowed identification of key molecular mechanisms involved in adipocyte differentiation. Novel therapeutic strategies are being developed on the basis of the pathophysiologic aspects of these syndromes.