Lipodystrophy: pathophysiology and advances in treatment

CASE REPORT OF SEVERE PROLIFERATIVE RETINOPATHY IN A PATIENT WITH CONGENITAL LIPODYSTROPHY

PURPOSE

A case report of a patient with severe proliferative retinopathy due to congenital lipodystrophy.

METHODS

We reviewed the medical history, imaging, and surgical procedures of a 25-year-old woman with a history of congenital lipodystrophy, presenting with bilateral combined tractional and exudative retinal detachment, poorly controlled diabetes mellitus, and extreme dislipidemia.

RESULTS

The patient underwent retinal detachment repair surgery both eyes. On the last follow-up, both retinae were flat, and visual acuity had improved in the right eye to J3 for near and finger counting 3 m for distance.

CONCLUSION

Surgery combining pars plana vitrectomy and scleral bucking successfully flattened both retinae and significantly improved visual acuity in one eye in this case of bilateral retinal detachment with combined tractional and exudative components in a patient with congenital lipodystrophy. Surgical control of retinal complications is thus possible, provided there is adequate control of the underlying risk factors.

Growth Hormone's Effect on Adipose Tissue: Quality versus Quantity

Obesity is an excessive accumulation or expansion of adipose tissue (AT) due to an increase in either the size and/or number of its characteristic cell type, the adipocyte. As one of the most significant public health problems of our time, obesity and its associated metabolic complications have demanded that attention be given to finding effective therapeutic options aimed at reducing adiposity or the metabolic dysfunction associated with its accumulation. Growth hormone (GH) has therapeutic potential due to its potent lipolytic effect and resultant ability to reduce AT mass while preserving lean body mass. However, AT and its resident adipocytes are significantly more dynamic and elaborate than once thought and require one not to use the reduction in absolute mass as a readout of efficacy alone. Paradoxically, therapies that reduce GH action may ultimately prove to be healthier, in part because GH also possesses potent anti-insulin activities along with concerns that GH may promote the growth of certain cancers. This review will briefly summarize some of the newer complexities of AT relevant to GH action and describe the current understanding of how GH influences this tissue using data from both humans and mice. We will conclude by considering the therapeutic use of GH or GH antagonists in obesity, as well as important gaps in knowledge regarding GH and AT.

Clinical presentations, metabolic abnormalities and end-organ complications in patients with familial partial lipodystrophy

OBJECTIVE

Familial partial lipodystrophy (FPLD) is a rare genetic disorder characterized by partial lack of subcutaneous fat.

METHODS

This multicenter prospective observational study included data from 56 subjects with FPLD (18 independent Turkish families). Thirty healthy controls were enrolled for comparison.

RESULTS

Pathogenic variants of the LMNA gene were determined in nine families. Of those, typical exon 8 codon 482 pathogenic variants were identified in four families. Analysis of the LMNA gene also revealed exon 1 codon 47, exon 5 codon 306, exon 6 codon 349, exon 9 codon 528, and exon 11 codon 582 pathogenic variants. Analysis of the PPARG gene revealed exon 3 p.Y151C pathogenic variant in two families and exon 7 p.H477L pathogenic variant in one family. A non-pathogenic exon 5 p.R215Q variant of the LMNB2 gene was detected in another family. Five other families harbored no mutation in any of the genes sequenced. MRI studies showed slightly different fat distribution patterns among subjects with different point mutations, though it was strikingly different in subjects with LMNA p.R349W pathogenic variant. Subjects with pathogenic variants of the PPARG gene were associated with less prominent fat loss and relatively higher levels of leptin compared to those with pathogenic variants in the LMNA gene. Various metabolic abnormalities associated with insulin resistance were detected in all subjects. End-organ complications were observed.

CONCLUSION

We have identified various pathogenic variants scattered throughout the LMNA and PPARG genes in Turkish patients with FPLD. Phenotypic heterogeneity is remarkable in patients with LMNA pathogenic variants related to the site of missense mutations. FPLD, caused by pathogenic variants either in LMNA or PPARG is associated with metabolic abnormalities associated with insulin resistance that lead to increased morbidity.

Effects of Epigallocatechin-3-Gallate on Autophagic Lipolysis in Adipocytes

Previous studies demonstrated effects of green tea on weight loss; however, green tea-induced modulation of adipocyte function is not fully understood. Here, we investigated effects of the major green tea phytochemical, epigallocatechin-3-gallate (EGCG) on triglyceride contents, lipolysis, mitochondrial function, and autophagy, in adipocytes differentiated from C₃H₁₀T1/2 cells and immortalized pre-adipocytes in vitro. EGCG reduced the triglycerol content significantly in adipocytes by 25%, comparable to the nutrient starvation state. EGCG did not affect protein kinase A signaling or brown adipocyte marker expression in adipocytes; however, EGCG increased autophagy, as measured by autophagy flux analysis and immunoblot analysis of LC3B, ATG7, and Beclin1. EGCG treatment reduced mitochondrial membrane potential by 56.8% and intracellular ATP levels by 49.1% compared to controls. Although mammalian target of rapamycin signaling was not upregulated by EGCG treatment, EGCG treatment induced AMP-activated protein kinase phosphorylation, indicating an energy-depleted state. In addition, EGCG increased the association between RAB7 and lipid droplets, suggesting that lipophagy was activated. Finally, knockdown of Rab7 attenuated the EGCG-dependent reduction in lipid contents. Collectively, these results indicated that EGCG upregulated autophagic lipolysis in adipocytes, supporting the therapeutic potential of EGCG as a caloric restriction mimetic to prevent obesity and obesity-related metabolic diseases.

CD36 Is a Marker of Human Adipocyte Progenitors with Pronounced Adipogenic and Triglyceride Accumulation Potential

White adipose tissue (WAT) expands in part through adipogenesis, a process involving fat cell generation and fatty acid (FA) storage into triglycerides (TGs). Several findings suggest that inter-individual and regional variations in adipogenesis are linked to metabolic complications. We aimed to identify cellular markers that define human adipocyte progenitors (APs) with pronounced adipogenic/TG storage ability. Using an unbiased single cell screen of passaged human adipose-derived stromal cells (hADSCs), we identified cell clones with similar proliferation rates but discordant capabilities to undergo adipogenic differentiation. Transcriptomic analyses prior to induction of differentiation showed that adipogenic clones displayed a significantly higher expression of CD36, encoding the scavenger receptor CD36. CD36+ hADSCs, in comparison with CD36-cells, displayed almost complete adipogenic differentiation while CD36 RNAi attenuated lipid accumulation. Similar findings were observed in primary CD45-/CD34+/CD31-APs isolated from human WAT where the subpopulation of MSCA1+/CD36+ cells displayed a significantly higher differentiation degree/TG storage capacity than MSCA1+/CD36-cells. Functional analyses in vitro and ex vivo confirmed that CD36 conferred APs an increased capacity to take up FAs thereby facilitating terminal differentiation. Among primary APs from subcutaneous femoral, abdominal and visceral human WAT, the fraction of CD36+ cells was significantly higher in depots associated with higher adipogenesis and reduced metabolic risk (i.e., femoral WAT). We conclude that CD36 marks APs with pronounced adipogenic potential, most probably by facilitating lipid uptake. This may be of value in developing human adipocyte cell clones and possibly in linking regional variations in adipogenesis to metabolic phenotype. Stem Cells 2017;35:1799-1814.

Fibroblast Growth Factor 21 Deficiency Attenuates Experimental Colitis-Induced Adipose Tissue Lipolysis

Aims

Nutrient deficiencies are common in patients with inflammatory bowel disease (IBD). Adipose tissue plays a critical role in regulating energy balance. Fibroblast growth factor 21 (FGF21) is an important endocrine metabolic regulator with emerging beneficial roles in lipid homeostasis. We investigated the impact of FGF21 in experimental colitis-induced epididymal white adipose tissue (eWAT) lipolysis.

Methods

Mice were given 2.5% dextran sulfate sodium (DSS) ad libitum for 7 days to induce colitis. The role of FGF21 was investigated using antibody neutralization or knockout (KO) mice. Lipolysis index and adipose lipolytic enzymes were determined. In addition, 3T3-L1 cells were pretreated with IL-6, followed by recombinant human FGF21 (rhFGF21) treatment; lipolysis was assessed.

Results

DSS markedly decreased eWAT/body weight ratio and increased serum concentrations of free fatty acid (FFA) and glycerol, indicating increased adipose tissue lipolysis. eWAT intracellular lipolytic enzyme expression/activation was significantly increased. These alterations were significantly attenuated in FGF21 KO mice and by circulating FGF21 neutralization. Moreover, DSS treatment markedly increased serum IL-6 and FGF21 levels. IL-6 pretreatment was necessary for the stimulatory effect of FGF21 on adipose lipolysis in 3T3-L1 cells.

Conclusions

Our results demonstrate that experimental colitis induces eWAT lipolysis via an IL-6/FGF21-mediated signaling pathway.

Partial lipodystrophy in patients who have undergone hematopoietic stem cell transplantation during childhood: an institutional cross-sectional survey

Partial lipodystrophy (PD), a condition similar to metabolic syndrome without obesity, is one of the late complications of hematopoietic stem cell transplantation (HSCT) performed during childhood. We aimed to investigate the prevalence and risk factors of PD. A cross-sectional survey was performed in a children’s hospital, targeting patients treated for a malignancy or hematological disorder, and who were disease-free for > 24 mo. PD was defined as gluteal lipoatrophy and lipohypertrophy of the cheeks or neck associated with diabetes and/or fatty liver disease. In total, 65 patients were enrolled. Six patients (9.2%) were judged to have PD, all of whom had received 10–14 Gy total body irradiation. Compared with the patients without PD, patients with PD were older at investigation (P < 0.01), had a longer elapsed time following HSCT (P < 0.01), had more frequent disease recurrence (P < 0.05), and were more likely to have undergone multiple HSCT (P < 0.05). In addition, they had higher blood pressure and showed higher levels of low-density lipoprotein-cholesterol and triglycerides, whereas their adiponectin levels were significantly lower. In conclusion, a large number of patients developed PD following HSCT, with unfavorable metabolic profiles at a later age, especially when they experienced a complex disease course.

A controlled-release mitochondrial protonophore reverses hypertriglyceridemia, nonalcoholic steatohepatitis, and diabetes in lipodystrophic mice

Lipodystrophy is a rare disorder characterized by complete or partial loss of adipose tissue. Patients with lipodystrophy exhibit hypertriglyceridemia, severe insulin resistance, type 2 diabetes, and nonalcoholic steatohepatitis (NASH). Efforts to ameliorate NASH in lipodystrophies with pharmacologic agents have met with limited success. We examined whether a controlled-release mitochondrial protonophore (CRMP) that produces mild liver-targeted mitochondrial uncoupling could decrease hypertriglyceridemia and reverse NASH and diabetes in a mouse model (fatless AZIP/F-1 mice) of severe lipodystrophy and diabetes. After 4 wk of oral CRMP (2 mg/kg body weight per day) or vehicle treatment, mice underwent hyperinsulinemic-euglycemic clamps combined with radiolabeled glucose to assess liver and muscle insulin responsiveness and tissue lipid measurements. CRMP treatment reversed hypertriglyceridemia and insulin resistance in liver and skeletal muscle. Reversal of insulin resistance could be attributed to reductions in diacylglycerol content and reduced PKC-ε and PKC-θ activity in liver and muscle respectively. CRMP treatment also reversed NASH as reflected by reductions in plasma aspartate aminotransferase and alanine aminotransferase concentrations; hepatic steatosis; and hepatic expression of IL-1α, -β, -2, -4, -6, -10, -12, CD69, and caspase 3 and attenuated activation of the IRE-1α branch of the unfolded protein response. Taken together, these results provide proof of concept for the development of liver-targeted mitochondrial uncoupling agents as a potential novel therapy for lipodystrophy-associated hypertriglyceridemia, NASH and diabetes.-Abulizi, A., Perry, R. J., Camporez, J. P. G., Jurczak, M. J., Petersen, K. F., Aspichueta, P., Shulman, G. I. A controlled-release mitochondrial protonophore reverses hypertriglyceridemia, nonalcoholic steatohepatitis, and diabetes in lipodystrophic mice.

Pituitary growth hormone (GH) secretion is partially rescued in HIV-infected patients with GH deficiency (GHD) compared to hypopituitary patients

Biochemical growth hormone deficiency is prevalent among human immunodeficiency virus-infected patients, but if this condition is clinically relevant remains challenging. The aim is to prospectively compare the growth hormone deficiency/insulin-like growth factor-1 status of 71 human immunodeficiency virus-infected patients with impaired growth hormone response to growth hormone releasing hormone + Arginine with that of 65 hypopituitary patients affected by a true growth hormone deficiency secondary to pituitary disease. The main outcomes were: basal serum growth hormone, insulin-like growth factor-1, insulin-like growth factor binding protein 3, growth hormone peak and area under the curve after growth hormone response to growth hormone releasing hormone + Arginine test, body mass index, waist and hip circumference, and body composition by dual energy X-ray absorptiometry. Insulin-like growth factor-1 binding protein 3, basal growth hormone (p < 0.005), growth hormone peak and area under the curve after growth hormone response to growth hormone releasing hormone + Arginine, waist to hip ratio, insulin-like growth factor-1, fasting glucose, insulin, and triglycerides (p < 0.0001) were lower in hypopituitary than human immunodeficiency virus-infected patients. Total and trunk fat mass by dual energy X-ray absorptiometry were higher in hypopituitary than in human immunodeficiency virus-infected patients (p < 0.0001). In all the patients total body fat was associated with both growth hormone peak and area under the curve at stepwise linear regression analysis. The degree of growth hormone deficiency is more severe in hypopituitary than in human immunodeficiency virus-infected patients, suggesting that the function of growth hormone/insulin-like growth factor-1 axis is partially rescued in the latter thanks to a preserved pituitary secretory reserve. Data from the current study suggest that human immunodeficiency virus-infected patients with peak growth hormone < 9 mg/L may have partial growth hormone deficiency and clinicians should be cautious before prescribing recombinant human growth hormone replacement treatment to patients living with human immunodeficiency virus.

Soy Protein Isolate Suppresses Lipodystrophy-induced Hepatic Lipid Accumulation in Model Mice

Lipodystrophies are acquired and genetic disorders characterized by the complete or partial absence of body fat with a line of metabolic disorders, including hepatic steatosis. Because soy protein isolate (SPI) has been reported to reduce cholesterol and triglyceride levels in animals and humans, we explored the effect of SPI on the pathophysiology of hepatic lipid accumutaion in a diet-induced lipodystrophy model mice. Four weeks of the lipodystrophy model diet induced hepatic lipid accumulation concomitant with marked deficiencies of adipose tissue and serum adipocytokines in mice. However, supplementing the lipodystrophy model diet with SPI could alleviate the hepatic lipid acculation without affecting the lipoatrophic effect of the diet. Enhanced lipogenesis is the principal mechanism of hepatic steatosis in this model, but SPI supplementation significantly attenuated the increase in enzyme activity and/or mRNA expression. Additionally, SPI supplementation upregulated the hepatic mRNA expression of an enzyme involved in cholesterol catabolism. In conclusion, our results indicate the possibility of dietary SPI to attenuate lipodystorophy-induced hepatic steatosis through the direct reduction of hepatic lipogenesis without affecting adipocytokine production.

Growth hormone deficiency and human immunodeficiency virus

Treatment with highly active antiretroviral drugs (HAART) is associated with several endocrine and metabolic comorbidities. Pituitary growth hormone (GH) secretion seems to be altered in human immunodeficiency virus (HIV) infection, and about one-third of patients have biochemical GH deficiency (GHD). We undertake a historical review of the functioning of the GH/insulin-like growth factor-1 (IGF-1) axis in patients with acquired immunodeficiency syndrome, and provide an overview of the main changes of the GH/IGF-1 axis occurring today in patients with HIV. Both spontaneous GH secretion and GH response to provocative stimuli are reduced in patients with HIV infection, especially in those with HIV-related lipodystrophy. The role of fat accumulation on flattened GH secretion is discussed, together with all factors able to potentially interfere with the pituitary secretion of GH. Several factors contribute to the development of GHD, but the pathophysiologic mechanisms involved in the genesis of GHD are complex and not yet fully elucidated owing to the difficulty in separating the effects of HIV infection from those of HAART, comorbidities and body changes. An update on the putative mechanisms involved in the pathogenesis of altered GH secretion in these patients is provided, together with an overview on the therapeutic strategies targeting the GH/IGF-1 axis to counteract fat redistribution associated with HIV-related lipodystrophy. The clinical significance of GHD in the context of HIV infection is discussed. The administration of tesamorelin, a GH releasing hormone analogue, is effective in reducing visceral fat in HIV-infected patients with lipodystrophy. This treatment is promising and safer than treatment with high doses of recombinant human growth hormone, which has several side-effects.

Cardiac Manifestations of Congenital Generalized Lipodystrophy

IN BRIEF Congenital lipodystrophy is a rare genetic disorder characterized by a near-complete absence of fat cells, hypoleptinemia leading to a voracious appetite, and marked insulin resistance. This article focuses on the known cardiovascular manifestations of patients with congenital lipodystrophy, including cardiomyopathy, cardiac arrhythmias, and accelerated atherosclerosis arising from a markedly deranged metabolic milieu. Future research that targets leptin deficiency (metreleptin) and apoC3 mRNA (antisense oligonucleotide) could open a window for potential pharmacological treatment of this challenging disorder.

Leptin and Hormones: Energy Homeostasis

Leptin, a 167 amino acid adipokine, plays a major role in human energy homeostasis. Its actions are mediated through binding to leptin receptor and activating JAK-STAT3 signal transduction pathway. It is expressed mainly in adipocytes, and its circulating levels reflect the body's energy stores in adipose tissue. Recombinant methionyl human leptin has been FDA approved for patients with generalized non-HIV lipodystrophy and for compassionate use in subjects with congenital leptin deficiency. The purpose of this review is to outline the role of leptin in energy homeostasis, as well as its interaction with other hormones.

Notch activation drives adipocyte dedifferentiation and tumorigenic transformation in mice

Adipocyte-specific activation of Notch signaling suppresses lipid metabolism pathways that provide ligands to Pparγ, leading to adipocyte dedifferentiation and development of liposarcomas (LPSs) resembling human dedifferentiated LPSs with complete penetrance. Pparγ ligand supplementation prevents liposarcoma development.

Liposarcomas (LPSs) are the most common soft-tissue cancer. Because of the lack of animal models, the cellular origin and molecular regulation of LPS remain unclear. Here, we report that mice with adipocyte-specific activation of Notch signaling (Ad/N1ICD) develop LPS with complete penetrance. Lineage tracing confirms the adipocyte origin of Ad/N1ICD LPS. The Ad/N1ICD LPS resembles human dedifferentiated LPS in histological appearance, anatomical localization, and gene expression signature. Before transformation, Ad/N1ICD adipocytes undergo dedifferentiation that leads to lipodystrophy and metabolic dysfunction. Although concomitant Pten deletion normalizes the glucose metabolism of Ad/N1ICD mice, it dramatically accelerates the LPS prognosis and malignancy. Transcriptomes and lipidomics analyses indicate that Notch activation suppresses lipid metabolism pathways that supply ligands to Pparγ, the master regulator of adipocyte homeostasis. Accordingly, synthetic Pparγ ligand supplementation induces redifferentiation of Ad/N1ICD adipocytes and tumor cells, and prevents LPS development in Ad/N1ICD mice. Importantly, the Notch target HES1 is abundantly expressed in human LPS, and Notch inhibition suppresses the growth of human dedifferentiated LPS xenografts. Collectively, ectopic Notch activation is sufficient to induce dedifferentiation and tumorigenic transformation of mature adipocytes in mouse.

Lipodystrophy Due to Adipose Tissue-Specific Insulin Receptor Knockout Results in Progressive NAFLD

Ectopic lipid accumulation in the liver is an almost universal feature of human and rodent models of generalized lipodystrophy and is also a common feature of type 2 diabetes, obesity, and metabolic syndrome. Here we explore the progression of fatty liver disease using a mouse model of lipodystrophy created by a fat-specific knockout of the insulin receptor (F-IRKO) or both IR and insulin-like growth factor 1 receptor (F-IR/IGFRKO). These mice develop severe lipodystrophy, diabetes, hyperlipidemia, and fatty liver disease within the first weeks of life. By 12 weeks of age, liver demonstrated increased reactive oxygen species, lipid peroxidation, histological evidence of balloon degeneration, and elevated serum alanine aminotransferase and aspartate aminotransferase levels. In these lipodystrophic mice, stored liver lipids can be used for energy production, as indicated by a marked decrease in liver weight with fasting and increased liver fibroblast growth factor 21 expression and intact ketogenesis. By 52 weeks of age, liver accounted for 25% of body weight and showed continued balloon degeneration in addition to inflammation, fibrosis, and highly dysplastic liver nodules. Progression of liver disease was associated with improvement in blood glucose levels, with evidence of altered expression of gluconeogenic and glycolytic enzymes. However, these mice were able to mobilize stored glycogen in response to glucagon. Feeding F-IRKO and F-IR/IGFRKO mice a high-fat diet for 12 weeks accelerated the liver injury and normalization of blood glucose levels. Thus, severe fatty liver disease develops early in lipodystrophic mice and progresses to advanced nonalcoholic steatohepatitis with highly dysplastic liver nodules. The liver injury is propagated by lipotoxicity and is associated with improved blood glucose levels.

Differential Roles of Insulin and IGF-1 Receptors in Adipose Tissue Development and Function

To determine the roles of insulin and insulin-like growth factor 1 (IGF-1) action in adipose tissue, we created mice lacking the insulin receptor (IR), IGF-1 receptor (IGF1R), or both using Cre-recombinase driven by the adiponectin promoter. Mice lacking IGF1R only (F-IGFRKO) had a ∼25% reduction in white adipose tissue (WAT) and brown adipose tissue (BAT), whereas mice lacking both IR and IGF1R (F-IR/IGFRKO) showed an almost complete absence of WAT and BAT. Interestingly, mice lacking only the IR (F-IRKO) had a 95% reduction in WAT, but a paradoxical 50% increase in BAT with accumulation of large unilocular lipid droplets. Both F-IRKO and F-IR/IGFRKO mice were unable to maintain body temperature in the cold and developed severe diabetes, ectopic lipid accumulation in liver and muscle, and pancreatic islet hyperplasia. Leptin treatment normalized blood glucose levels in both groups. Glucose levels also improved spontaneously by 1 year of age, despite sustained lipodystrophy and insulin resistance. Thus, loss of IR is sufficient to disrupt white fat formation, but not brown fat formation and/or maintenance, although it is required for normal BAT function and temperature homeostasis. IGF1R has only a modest contribution to both WAT and BAT formation and function.

Naringin improves zidovudine- and stavudine-induced skeletal muscle complications in rats

Chronic use of nucleoside reverse transcriptase inhibitors (NRTIs) in managing human immunodeficiency virus (HIV) infection has been associated with several complications. Available management options for these complications have yielded controversial results, thus the need to urgently find newer alternatives. Naringin, a plant-derived flavonoid, has been shown to possess antioxidant and antiapoptotic properties which can be exploited in managing NRTI-induced complications. This study therefore investigated the effects of naringin on some NRTI-induced complications. Forty-nine rats (200-250 g) were divided into seven groups and were orally treated with stavudine (d4T)-only, d4T + naringin, d4T + vitamin E, zidovudine (AZT)-only, AZT + naringin, AZT + vitamin E, and distilled water, respectively. Drugs were administered once daily for 56 days, and oral glucose tolerance tests conducted on day 54 of the experiments and rats were thereafter sacrificed on day 56 by halothane overdose. Plasma samples and the left gastrocnemius muscles were stored at -80°C for further analysis. There was significant glucose intolerance, insulin resistance, oxidative stress, and apoptosis in the skeletal muscles of AZT- or d4T-only-treated rats. Naringin, however, significantly reduced fasting blood glucose and fasting plasma insulin concentrations, mitigated glucose intolerance, and insulin resistance in addition to reducing malondialdehyde and carbonyl protein concentrations when coadministered with either NRTIs. Furthermore, naringin improved antioxidant enzyme activities, reduced skeletal muscle BCL-2-associated X protein expression, and improved B-cell lymphoma-2 protein expression compared to AZT- or d4T-only-treated rats. Naringin ameliorated AZT- and d4T-induced complications and therefore should be further investigated as a possible nutritional supplement in managing HIV infection.

Barraquer-Simons syndrome: a rare form of acquired lipodystrophy

Background

Human lipodystrophies are uncommon disorders, with important clinical consequences, which are often undiagnosed. The Barraquer–Simons syndrome is a form of partial symmetric lipodystrophy of unknown etiology, characterized by the loss of subcutaneous adipose tissue, limited to upper part of the body. Insulin resistance and metabolic complications are less common than with other lipodystrophy subtypes. Patients usually have decreased serum complement-component 3 levels, associated with complement activation by the alternative pathway, which may indicate the presence of renal involvement.

Case presentation

The authors report a case of a 31-year-old woman with progressive loss of subcutaneous fat, limited to the face, neck and thorax. She presented no severe metabolic complications, neither signs of insulin resistance. Laboratory tests revealed mild dyslipidemia, and low serum levels of complement-component 3. Clinical and biochemical characteristics were consistent with the diagnosis of Barraquer–Simons syndrome.

Conclusion

The present case illustrates the importance of recognizing the clinical features of this lipodystrophic syndrome, which may present potentially severe consequences and psychological distress. A brief overview is made, addressing the clinical signs of the disease, its course, and how to manage it.

Heterogeneity of white adipose tissue: molecular basis and clinical implications

Adipose tissue is a highly heterogeneous endocrine organ. The heterogeneity among different anatomical depots stems from their intrinsic differences in cellular and physiological properties, including developmental origin, adipogenic and proliferative capacity, glucose and lipid metabolism, insulin sensitivity, hormonal control, thermogenic ability and vascularization. Additional factors that influence adipose tissue heterogeneity are genetic predisposition, environment, gender and age. Under obese condition, these depot-specific differences translate into specific fat distribution patterns, which are closely associated with differential cardiometabolic risks. For instance, individuals with central obesity are more susceptible to developing diabetes and cardiovascular complications, whereas those with peripheral obesity are more metabolically healthy. This review summarizes the clinical and mechanistic evidence for the depot-specific differences that give rise to different metabolic consequences, and provides therapeutic insights for targeted treatment of obesity.

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.

Naringin Reverses Hepatocyte Apoptosis and Oxidative Stress Associated with HIV-1 Nucleotide Reverse Transcriptase Inhibitors-Induced Metabolic Complications

Nucleoside Reverse Transcriptase Inhibitors (NRTIs) have not only improved therapeutic outcomes in the treatment of HIV infection but have also led to an increase in associated metabolic complications of NRTIs. Naringin’s effects in mitigating NRTI-induced complications were investigated in this study. Wistar rats, randomly allotted into seven groups (n = 7) were orally treated daily for 56 days with 100 mg/kg zidovudine (AZT) (groups I, II III), 50 mg/kg stavudine (d4T) (groups IV, V, VI) and 3 mL/kg of distilled water (group VII). Additionally, rats in groups II and V were similarly treated with 50 mg/kg naringin, while groups III and VI were treated with 45 mg/kg vitamin E. AZT or d4T treatment significantly reduced body weight and plasma high density lipoprotein concentrations but increased liver weights, plasma triglycerides and total cholesterol compared to controls, respectively. Furthermore, AZT or d4T treatment significantly increased oxidative stress, adiposity index and expression of Bax protein, but reduced Bcl-2 protein expression compared to controls, respectively. However, either naringin or vitamin E significantly mitigated AZT- or d4T-induced weight loss, dyslipidemia, oxidative stress and hepatocyte apoptosis compared to AZT- or d4T-only treated rats. Our results suggest that naringin reverses metabolic complications associated with NRTIs by ameliorating oxidative stress and apoptosis. This implies that naringin supplements could mitigate lipodystrophy and dyslipidemia associated with NRTI therapy.

HMGA1 overexpression in adipose tissue impairs adipogenesis and prevents diet-induced obesity and insulin resistance

High-Mobility-Group-A1 (HMGA1) proteins are non-histone proteins that regulate chromatin structure and gene expression during embryogenesis, tumourigenesis and immune responses. In vitro studies suggest that HMGA1 proteins may be required to regulate adipogenesis. To examine the role of HMGA1 in vivo, we generated transgenic mice overexpressing HMGA1 in adipose tissues. HMGA1 transgenic mice showed a marked reduction in white and brown adipose tissue mass that was associated with downregulation of genes involved in adipogenesis and concomitant upregulation of preadipocyte markers. Reduced adipogenesis and decreased fat mass were not associated with altered glucose homeostasis since HMGA1 transgenic mice fed a regular-chow diet exhibited normal glucose tolerance and insulin sensitivity. However, when fed a high-fat diet, overexpression of HMGA1 resulted in decreased body-weight gain, reduced fat mass, but improved insulin sensitivity and glucose tolerance. Although HMGA1 transgenic mice exhibited impaired glucose uptake in adipose tissue due to impaired adipogenesis, the increased glucose uptake observed in skeletal muscle may account for the improved glucose homeostasis. Our results indicate that HMGA1 plays an important function in the regulation of white and brown adipogenesis in vivo and suggests that impaired adipocyte differentiation and decreased fat mass is not always associated with impaired whole-body glucose homeostasis.

New advances in the treatment of generalized lipodystrophy: role of metreleptin

Recombinant methionyl human leptin or metreleptin is a synthetic leptin analog that has been trialed in patients with leptin-deficient conditions, such as leptin deficiency due to mutations in the leptin gene, hypothalamic amenorrhea, and lipodystrophy syndromes. These syndromes are characterized by partial or complete absence of adipose tissue and hormones derived from adipose tissue, most importantly leptin. Patients deficient in leptin exhibit a number of severe metabolic abnormalities such as hyperglycemia, hypertriglyceridemia, and hepatic steatosis, which can progress to diabetes mellitus, acute pancreatitis, and hepatic cirrhosis, respectively. For the management of these abnormalities, multiple therapies are usually required, and advanced stages may be progressively difficult to treat. Following many successful trials, the US Food and Drug Administration approved metreleptin for the treatment of non-HIV-related forms of generalized lipodystrophy. Leptin replacement therapy with metreleptin has, in many cases, reversed these metabolic complications, with improvements in glucose-insulin-lipid homeostasis, and regression of fatty liver disease. Besides being effective, a daily subcutaneous administration of metreleptin is generally safe, but the causal association between metreleptin and immune complications (such as lymphoma) is still unclear. Moreover, further investigation is needed to elucidate mechanisms by which metreleptin leads to the development of anti-leptin antibodies. Herein, we review clinical aspects of generalized lipodystrophy and the pharmacological profile of metreleptin. Further, we examine studies that assessed the safety and efficacy of metreleptin, and outline some clinical perspectives on the drug.

Intracellular leptin signaling following effective weight loss

AIM

To investigate the effect of ex-vivo leptin treatment before and after weight loss on key-molecules of intracellular leptin signaling in peripheral blood mononuclear cells (PBMCs) of obese women.

MATERIALS AND METHODS

Five healthy obese women underwent a 12-week medical nutrition treatment aiming at inducing 10% weight loss. Isolated PBMCs at baseline, and at weeks 8 and 12 were treated with increasing leptin doses (0, 25 and 75 ng/ml) for 30 min. The phosphorylation of signal transducer and activator of transcription (STAT)3, extracellular-signal-regulated kinase (ERK), protein kinase B (Akt) and 5' adenosine monophosphate-activated protein kinase (AMPK) of PBMCs was analyzed using Western blotting.

RESULTS

Women lost 10 ± 1% and 13 ± 1% of weight at week 8 and 12, respectively. Circulating leptin and insulin significantly decreased from 39.5 ± 7.7 to 12.2 ± 2.4 ng/ml (p = 0.026) and from 13.0 ± 1.6 to 5.4 ± 0.9 μU/ml (p = 0.005) at week 12, respectively. In the ex vivo study, a significant decrease in STAT3 phosphorylation was observed in the control group after weight loss. Treatment of PBMCs with leptin 75 ng/ml increased significantly ERK, STAT3 and Akt phosphorylation, but no weight loss induced change was observed in response to leptin treatment ex vivo.

CONCLUSIONS

A 10%-15% weight loss decreases baseline STAT3 phosphorylation ex vivo, but does not alter the effect of increasing doses of leptin on the incremental intracellular phosphorylation of STAT3, ERK, Akt and AMPK. Supraphysiologic leptin doses (75 ng/ml) result in higher protein phosphorylation compared to either physiologic doses or no treatment, before and after weight loss.

Development of metabolic syndrome at a young age as a manifestation of familial partial lipodystrophy type 3 (PPARG mutation): the first description of its clinical case in Russia

Metabolic syndrome (MS) is extremely common (20%–25% of the world’s population), and its diagnostic criteria are defined and well known. It has been shown that patients who have MS are twice as likely to die from a cardiovascular complication and three times as likely to suffer from it compared with patients without MS. However, the underlying cause of MS remains to be clearly elucidated, although inherited factors, such as insulin resistance (IR), and external factors are considered to play a key role in this process. Special attention should be paid to MS in young patients, who may present the first manifestation of inherited lipodystrophy. The study describes the first known family in Russia (three clinical cases) with familial partial lipodystrophy (FPLD) type 3 caused by heterozygous p.R212Q PPARG mutation (MIM#601487). The study reports rare forms of inherited IR, such as FPLD, and contributes to a better understanding of common disorders such as MS.

FGF21 mediates alcohol-induced adipose tissue lipolysis by activation of systemic release of catecholamine in mice

Alcohol consumption leads to adipose tissue lipoatrophy and mobilization of FFAs, which contributes to hepatic fat accumulation in alcoholic liver disease. This study aimed to investigate the role of fibroblast growth factor (FGF)21, a metabolic regulator, in the regulation of chronic-binge alcohol-induced adipose tissue lipolysis. FGF21 KO mice were subjected to chronic-binge alcohol exposure, and epididymal white adipose tissue lipolysis and liver steatosis were investigated. Alcohol exposure caused adipose intracellular cAMP elevation and activation of lipolytic enzymes, leading to FFA mobilization in both WT and FGF21 KO mice. However, alcohol-induced systemic elevation of catecholamine, which is known to be a major player in adipose lipolysis by binding to the β-adrenergic receptor, was markedly inhibited in KO mice. Supplementation with recombinant human FGF21 to alcohol-exposed FGF21 KO mice resulted in an increase in fat loss in parallel with an increase of circulating norepinephrine concentration. Furthermore, alcohol consumption-induced fatty liver was blunted in the KO mice, indicating an inhibition of fatty acid reverse transport from adipose to the liver in the KO mice. Taken together, our studies demonstrate that FGF21 KO mice are protected from alcohol-induced adipose tissue excess-lipolysis through a mechanism involving systemic catecholamine release.

[Familial partial lipodystrophy (Dunnigan syndrome) due to LMNA gene mutation: The first description of its clinical case in Russia]

Hereditary lipodystrophies (HLD) are a heterogeneous group of rare diseases characterized by a complete or partial loss of subcutaneous fat and by the development of metabolic disturbances: diabetes mellitus with obvious insulin resistance and acanthosis nigricans, dyslipidemia, hepatic steatosis, hypertension, and polycystic ovary syndrome. The laminopathy variant familial partial lipodystrophy type 2 or Dunnigan syndrome (FPLD2) is the most common cause of partial LD. The paper describes a family (3 clinical cases) with FPLD2 caused by heterozygous R482W missense mutations in the gene encoding the protein lamin A/C (LMNA; 150330). This observation demonstrates that specialists should be more aware of this disease and make a timely diagnose in cases of concurrent severe metabolic disturbances at a young age, which contributes to more effective treatment of patients and to medical genetic counseling of their families.

Endocrine and Metabolic Effects of Adipose Tissue in Children and Adolescents

Adipose tissue is implicated in many endocrine and metabolic processes. Leptin was among the first identified adipose-secreted factors, which act in an auto-, para- and endocrine manner. Since leptin, many other adipose tissue factors were determined, some primarily secreted from the adipocytes, some from other cells of the adipose tissue.

So-called adipokines are not only involved in obesity and its complications, as are insulin resistance, type 2 diabetes and other components of the metabolic syndrome, but also in growth, reproduction, bone metabolism, immune response, cancer development and many other important biological processes. Research in the field of adipokines has revealed new insights into the physiological and pathophysiologal processes and opened new therapeutic possibilities. In the present article, a special emphasis is devoted to research in children and adolescents.

Identification and saturable nature of signaling pathways induced by metreleptin in humans: comparative evaluation of in vivo, ex vivo, and in vitro administration

Signaling pathways activated by leptin in metabolically important organs have largely been studied only in animal and/or cell culture studies. In this study, we examined whether leptin has similar effects in human peripheral tissues in vivo, ex vivo, and in vitro and whether the response would be different in lean and obese humans. For in vivo leptin signaling, metreleptin was administered and muscle, adipose tissue, and peripheral blood mononuclear cells were taken for analysis of signal activation. Experiments were also done ex vivo and with primary cultured cells in vitro. The signal activation was compared between male versus female and obese versus lean humans. Acute in vivo, ex vivo, and/or in vitro metreleptin administration similarly activated STAT3, AMPK, ERK1/2, Akt, mTOR, NF-κB, and/or IKKα/β without any differences between male versus female and obese versus lean subjects. All signaling pathways were saturable at ∼30-50 ng/mL, consistent with the clinical evidence showing no additional effect(s) in obese subjects who already have high levels of leptin. Our data provide novel information on downstream effectors of metreleptin action in humans that may have therapeutic implications.

HIV/AIDS and lipodystrophy: implications for clinical management in resource-limited settings

Introduction

Lipodystrophy is a term used to describe a metabolic complication of fat loss, fat gain, or a combination of fat loss and gain, which is associated with some antiretroviral (ARV) therapies given to HIV-infected individuals. There is limited research on lipodystrophy in low- and middle-income countries, despite accounting for more than 95% of the burden of HIV/AIDS. The objective of this review was to evaluate the prevalence, pathogenesis and prognosis of HIV-related lipoatrophy, lipohypertrophy and mixed syndrome, to inform clinical management in resource-limited settings.

Methods

We conducted a structured literature search using MEDLINE electronic databases. Relevant MeSH terms were used to identify published human studies on HIV and lipoatrophy, lipohypertrophy, or mixed syndrome in low-, low-middle- and upper-middle-income countries through 31 March 2014. The search resulted in 5296 articles; after 1599 studies were excluded (958 reviews, 641 non-human), 3697 studies were extracted for further review. After excluding studies conducted in high-income settings (n=2808), and studies that did not meet inclusion criteria (n=799), 90 studies were included in this review.

Results and Discussion

Of the 90 studies included in this review, only six were from low-income countries and eight were from lower middle-income economies. These studies focused on lipodystrophy prevalence, risk factors and side effects of antiretroviral therapy (ART). In most studies, lipodystrophy developed after the first six months of therapy, particularly with the use of stavudine. Lipodystrophy is associated with increased risk of cardiometabolic complications. This is disconcerting and anticipated to increase, given the rapid scale-up of ART worldwide, the increasing number and lifespan of HIV-infected patients on long-term therapy, and the emergence of obesity and non-communicable diseases in settings with extensive HIV burden.

Conclusions

Lipodystrophy is common in resource-limited settings, and has considerable implications for risk of metabolic diseases, quality of life and adherence. Comprehensive evidence-based interventions are urgently needed to reduce the burden of HIV and lipodystrophy, and inform clinical management in resource-limited settings.

Leptin in congenital and HIV-associated lipodystrophy

Leptin is a hormone secreted by adipocytes that regulates energy metabolism via peripheral action on glucose synthesis and utilization as well as through central regulation of food intake. Patients with decreased amounts of fat in their adipose tissue (lipoatrophy) will have low leptin levels, and hypoleptinemic states have been associated with a variety of metabolic dysfunctions. Pronounced complications of insulin resistance, dyslipidemia and fatty liver are observed in patients suffering from congenital or acquired generalized lipodystrophy while somewhat less pronounced abnormalities are associated with human immunodeficiency virus (HIV) and the use of highly active antiretroviral therapy, the so-called HIV-associated lipodystrophy. Previous uncontrolled open-label studies have demonstrated that physiological doses of leptin repletion have corrected many of the metabolic derangements observed in subjects with rare fat maldistribution syndromes such as generalized lipodystrophy. In the much more commonly encountered HIV-associated lipodystrophy, leptin replacement has been shown to decrease central fat mass and to improve insulin sensitivity, dyslipidemia, and glucose levels. The United States Food and Drug Administration has recently granted approval for recombinant leptin therapy for congenital and acquired generalized lipodystrophy, however large, well-designed, placebo-controlled studies are needed to assess long-term efficacy, safety and adverse effects of leptin replacement. In this review, we present the role of leptin in the metabolic complications of congenital and acquired lipodystrophy and discuss current and emerging clinical therapeutic uses of leptin in humans with lipodystrophy.

The role of leptin in regulating bone metabolism

Leptin was initially best known for its role in energy homeostasis and regulation of energy expenditure. In the past few years we have realized that leptin also plays a major role in neuroendocrine regulation and bone metabolism. Here, we review the literature the indirect and direct pathways through which leptin acts to influence bone metabolism and discuss bone abnormalities related to leptin deficiency in both animal and human studies. The clinical utility of leptin in leptin deficient individuals and its potential to improve metabolic bone disease are also discussed. We are beginning to understand the critical role leptin plays in bone metabolism; future randomized studies are needed to fully assess the potential and risk-benefit of leptin's use in metabolic bone disease particularly in leptin deficient individuals.

Leptin: A hormone linking activation of neuroendocrine axes with neuropathology

Leptin, a peptide hormone secreted by adipocytes, plays a central role in controlling appetite and weight in both rodents and humans. Basic science and clinical research suggest that this hormone not only affects the regulation of the neuroendocrine axes, but also exerts effects on the central nervous system with subsequent alterations in psychological functions. For instance, leptin suppresses cortisol secretion during stress-related activation of the adrenal axis. As psychiatric disorders like depression are associated with hypercortisolism, leptin is proposed to exert anti-depressant-like effects due to its inhibition of chronically overactive hypothalamo-pituitary-adrenal axis function. Moreover, leptin status of depressed patients could serve as a prognostic marker for therapy response. Besides its influence on neuroendocrine pathways leptin seems to have direct central effects on brain development and neuroplasticity. Low leptin levels have been shown to be associated with increased risk of developing dementia, supporting the idea of a pro-cognitive effect of leptin. These areas may have direct clinical implications and deserve to be studied further in the future.

Leptin replacement therapy for the treatment of non-HAART associated lipodystrophy syndromes: a meta-analysis into the effects of leptin on metabolic and hepatic endpoints

The clinical manifestations of lipodystrophy syndromes (LS) are hypoleptinemia, hyperglycemia, insulin resistance, dyslipidemia and hepatic steatosis. Leptin replacement therapy (LRT) is effective at improving these pathologies. Currently, there are no data compiling the evidence from the literature, and demonstrating the effect of LRT in LS patients. A systematic review of the MEDLINE and Cochrane Library databases was conducted to identify studies assessing the effect of LRT on metabolic and hepatic endpoints in patients with LS not associated with highly active antiretroviral therapy (HAART) use. Standardized mean differences (SMD) and 95% confidence intervals of pooled results were calculated for overall changes in glucose homeostasis, lipid profile, and hepatic physiology, using an inverse-variance random-effects model. After screening, 12 studies were included for review. Meta-analysis of results from 226 patients showed that LRT decreased fasting glucose [0.75 SMD units (range 0.36‐1.13), p=0.0001], HbA1c [0.49 (0.17‐0.81), p=0.003], triglycerides [1.00 (0.69‐1.31), p<0.00001], total cholesterol [0.62 (0.21‐1.02), p=0.003], liver volume [1.06 (0.51‐1.61), p=0.0002] and AST [0.41 (0.10‐0.73) p=0.01]. In patients with non-HAART LS, LRT improves the outcome of several metabolic and hepatic parameters. Studies were limited by small populations and therefore large prospective trials are needed to validate these findings.

Identification of a novel mutation in the polymerase delta 1 (POLD1) gene in a lipodystrophic patient affected by mandibular hypoplasia, deafness, progeroid features (MDPL) syndrome

OBJECTIVE

Progressive lipodystrophy is one of the major features of the rare MDPL syndrome. Until now, 9 patients affected by this syndrome have been described and a recent study identified in 4 of them an in-frame deletion (Ser605del) of a single codon in the POLD1 gene. Sequence alterations of the POLD1 gene at different sites have been previously reported in human colorectal and endometrial carcinomas.

MATERIALS/METHODS

A 48-year-old woman was admitted to our department for the assessment of a previously diagnosed lipodystrophy. She did not report a family history of diabetes or other metabolic disorders. Hypertriglyceridemia was diagnosed incidentally when she was 25years old. At that time she was also diagnosed with sensorineural bilateral hearing loss. At physical examination she presented lipoatrophy affecting nearly the entire body, mandibular hypoplasia, bird-like face, beaked nose, progeroid facial features, with crowded teeth, small mouth and uvula. Abdominal ultrasound showed hepatomegaly and hepatosteatosis. Fat mass index measured with DXA was 4.59kg/m(2), indicating a fat deficit; the oral glucose tolerance test showed an impaired glucose tolerance.

RESULTS

Sequence analysis of the entire coding region of the POLD1 gene, disclosed a novel heterozygous mutation in exon 13 (R507C).

CONCLUSION

The MDPL patient herein described harbors a novel mutation in the exonuclease domain of POLD1. This new variant provides further evidence for a role of POLD1 in the pathogenesis of MDPL. The mechanisms that link changes at various sites of the protein with different diseases remain to be clarified.

Thiazolidinediones and the promise of insulin sensitization in type 2 diabetes

Type 2 diabetes is caused by insulin resistance coupled with an inability to produce enough insulin to control blood glucose, and thiazolidinediones (TZDs) are the only current antidiabetic agents that function primarily by increasing insulin sensitivity. However, despite clear benefits in glycemic control, this class of drugs has recently fallen into disuse due to concerns over side effects and adverse events. Here we review the clinical data and attempt to balance the benefits and risks of TZD therapy. We also examine potential mechanisms of action for the beneficial and harmful effects of TZDs, mainly via agonism of the nuclear receptor PPARγ. Based on critical appraisal of both preclinical and clinical studies, we discuss the prospect of harnessing the insulin sensitizing effects of PPARγ for more effective, safe, and potentially personalized treatments of type 2 diabetes.

20 years of leptin: role of leptin in human reproductive disorders

Leptin, as a key hormone in energy homeostasis, regulates neuroendocrine function, including reproduction. It has a permissive role in the initiation of puberty and maintenance of the hypothalamic-pituitary-gonadal axis. This is notable in patients with either congenital or acquired leptin deficiency from a state of chronic energy insufficiency. Hypothalamic amenorrhea is the best-studied, with clinical trials confirming a causative role of leptin in hypogonadotropic hypogonadism. Implications of leptin deficiency have also emerged in the pathophysiology of hypogonadism in type 1 diabetes. At the other end of the spectrum, hyperleptinemia may play a role in hypogonadism associated with obesity, polycystic ovarian syndrome, and type 2 diabetes. In these conditions of energy excess, mechanisms of reproductive dysfunction include central leptin resistance as well as direct effects at the gonadal level. Thus, reproductive dysfunction due to energy imbalance at both ends can be linked to leptin.

Lipodystrophy syndrome in HIV treatment-multiexperienced patients: implication of resistin

BACKGROUND

Impaired production of adipocytokines is a major factor incriminated in the occurrence of lipodystrophy (LD).

OBJECTIVE

To evaluate LD prevalence and subtypes in HIV treatment-multiexperienced patients, and to determine the correlations between adipocytokines and LD subtypes.

METHODS

Cross-sectional study in a Romanian tertiary care hospital, between 2008 and 2010, in HIV-positive patients, undergoing cART for ≥6 months. LD diagnosis, based on clinical and anthropometric data, was classified into lipoatrophy (LA), lipohypertrophy (LH) and mixed fat redistribution (MFR). Blood samples were collected for leptin, adiponectin and resistin assessments.

RESULTS

We included 100 patients, 44 % with LD, among which LA had 63 %. LA patients had sex ratio, median age, treatment duration and median number of ARV regimens of 1, 20, 93 and 3.5 compared to non-LD patients: 1.65, 31, 44 and 1. LH and MFR patients were older and had higher total and LDL cholesterol versus non-LD patients. For both overall group and female group, LA was associated in univariate and multivariate analysis with increased resistin (p = 0.02 and 0.04) and number of ARV regimens (p < 0.001). Determination coefficient (Nagelkerke R (2)) of increased resistin and the number of ARV combinations in the presence of LA was 33 % in overall group and 47 % in female patients.

CONCLUSIONS

In our young HIV-positive population, LD had high prevalence with predominance of LA subtype. LA was associated with high resistin levels and greater number of ARV regimens in overall group and female subgroup. Resistin could be used as a marker of peripheral adipose tissue loss and might be used as a target for new anti-LD therapeutic strategies.

Adipocytes in skin health and disease

Adipocytes are intimately associated with the dermal compartment of the skin, existing in a specialized dermal depot and displaying dynamic changes in size during tissue homeostasis. However, the roles of adipocytes in cutaneous biology and disease are not well understood. Traditionally, adipocytes within tissues were thought to act as reservoirs of energy, as thermal, or as structural support. In this review, we discuss recent studies revealing the cellular basis of the dynamic development and regenerative capacity of dermal adipocytes associated with the hair cycle and following injury. We discuss and speculate on potential roles of dermal adipocytes in cutaneous biology with an emphasis on communication during hair follicle growth and wound healing. Finally, we explore how alterations in the dermal adipose tissue may support clinical manifestations of cutaneous diseases such as lipodystrophy, obesity, and alopecia.

Divergent metabolic phenotype between two sisters with congenital generalized lipodystrophy due to double AGPAT2 homozygous mutations. a clinical, genetic and in silico study

Congenital generalized lipodystrophy (CGL) is a rare autosomal recessive disorder characterized by extreme reduction of white adipose tissue (WAT) mass. CGL type 1 is the most frequent form and is caused by mutations in AGPAT2. Genetic and clinical studies were performed in two affected sisters of a Chilean family. These patients have notoriously dissimilar metabolic abnormalities that correlate with differential levels of circulating leptin and soluble leptin receptor fraction. Sequencing of AGPAT2 exons and exon-intron boundaries revealed two homozygous mutations in both sisters. Missense mutation c.299G>A changes a conserved serine in the acyltransferase NHX4D motif of AGPAT2 (p.Ser100Asn). Intronic c.493-1G>C mutation destroy a conserved splicing site that likely leads to exon 4 skipping and deletion of whole AGPAT2 substrate binding domain. In silico protein modeling provided insights of the mechanisms of lack of catalytic activity owing to both mutations.

LMNA gene mutation as a model of cardiometabolic dysfunction: from genetic analysis to treatment response

AIM

This report highlights the metabolic, endocrine and cardiovascular comorbidities in a case of familial partial lipodystrophy (FPLD), and also evaluates the efficacy and safety of metformin therapy.

METHODS

Mutational analysis was carried out of the LMNA gene in a teenage girl with an FPLD phenotype. Insulin resistance, sex hormones and metabolic parameters were also evaluated, and echocardiography, electrocardiography and 24-h blood pressure monitoring were also done.

RESULTS

The patient showed atypical fat distribution, insulin resistance and hypertrophic cardiomyopathy. Physical examination revealed muscle hypertrophy with a paucity of fat in the extremities, trunk and gluteal regions, yet excess fat deposits in the face, neck and dorsal cervical region. LMNA sequencing revealed a heterozygous missense mutation (c.1543A>G) in exon 9, leading to substitution of lysine by glutamic acid at position 515 (K515E). Moderate hypertension and secondary polycystic ovary syndrome were also assessed. Treatment with metformin resulted in progressive improvement of metabolic status, while blood pressure values normalized with atenolol therapy.

CONCLUSIONS

Very rapid and good results with no side-effects were achieved with metformin therapy for FPLD. The association of an unusual mutation in the LMNA gene was also described.

Metreleptin: first global approval

Metreleptin is an analogue of the human hormone leptin being developed by Amylin Pharmaceuticals (a subsidiary of Bristol-Myers Squibb) for the subcutaneous treatment of metabolic disorders including lipodystrophy. The compound is expected to improve insulin sensitivity, hypertriglyceridaemia and hyperglycaemia in patients with lipodystrophy who are unresponsive to conventional treatment. Metreleptin has been approved in Japan as a leptin therapy for the treatment of lipodystrophy. Amylin has also completed a submission for regulatory approval to the US FDA for metreleptin in the treatment of diabetes mellitus and/or hypertriglyceridaemia in patients with rare forms of lipodystrophy. Clinical development of the drug is also underway in the USA for the treatment of type 1 diabetes. Amgen was previously assessing the use of metreleptin as a treatment for amenorrhoea; however, it appears that development in this indication has been discontinued. This article summarizes the milestones in the development of metreleptin leading to this first approval for lipodystrophy.

Higher fetuin-A, lower adiponectin and free leptin levels mediate effects of excess body weight on insulin resistance and risk for myelodysplastic syndrome

OBJECTIVE

Excess body weight has been implicated in the pathogenesis of myelodysplastic syndrome (MDS). We thus explored the role of serum fetuin-A reflecting ectopic hepatic fat deposition when storage capacity of adipocytes has been exceeded, free leptin reflecting overall fat mass and adiponectin reflecting visceral fat mass, all potential mediators of the effects of obesity on insulin resistance and, consequently, to MDS risk.

MATERIALS & METHODS

In a hospital-based case-control study, we studied 101 cases with incident, histologically confirmed primary MDS and 101 controls matched on gender, age and date of diagnosis, between 2004 and 2007. Serum fetuin-A, adiponectin, leptin, leptin receptor, free leptin and insulin were determined.

RESULTS

Higher serum fetuin-A, lower adiponectin and lower free leptin were all individually and independently associated with higher risk of MDS before and after controlling for matching and risk factors, such as age, gender, date of diagnosis, body mass index (BMI), family history of lymphohematopoietic cancer, smoking history and serum insulin. Interestingly, we have shown that these associations were prominent among overweight/obese individuals and persisted after controlling for BMI and serum insulin indicating that their effects are above and beyond insulinemia only.

CONCLUSION

Elevated serum fetuin-A but lower adiponectin and free leptin are associated with higher risk of MDS particularly among overweight/obese individuals. These findings suggest that the association between excessive weight gain and the risk of MDS could be mediated by fetuin-A, adiponectin and free leptin, which may have potential clinical and preventive implications.

Abnormal adipose tissue distribution with unfavorable metabolic profile in five children following hematopoietic stem cell transplantation: a new etiology for acquired partial lipodystrophy

We report five consecutive patients who underwent hematopoietic stem cell transplantation (HSCT) to treat leukemia or neuroblastoma early in their lives and later manifested abnormal patterns of adipose tissue distribution. Lipoatrophy was remarkable in the gluteal regions and extremities, whereas subcutaneous fat was preserved in the cheeks, neck, and abdomen. In addition, visceral fat deposition, fatty changes in the liver, and metabolic derangements such as insulin resistance and hypertriglyceridemia were evident. These features resemble Dunnigan-type familial partial lipodystrophy, which is a rare condition caused by LMNA gene mutation. These patients shared a common medical history involving HSCT, including conditioning with total body irradiation (TBI). They also received intensive chemotherapy because of multiple metastases (n = 3), relapse (n = 3), and repetitive HSCT (n = 3). We propose HSCT as a new etiology for acquired partial lipodystrophy and recommend that patients who undergo HSCT with TBI and intensive chemotherapy early in their lives must receive careful observation for the possible development of lipodystrophy and metabolic complications.

Abnormal adipose tissue distribution with unfavorable metabolic profile in five children following hematopoietic stem cell transplantation: a new etiology for acquired partial lipodystrophy

We report five consecutive patients who underwent hematopoietic stem cell transplantation (HSCT) to treat leukemia or neuroblastoma early in their lives and later manifested abnormal patterns of adipose tissue distribution. Lipoatrophy was remarkable in the gluteal regions and extremities, whereas subcutaneous fat was preserved in the cheeks, neck, and abdomen. In addition, visceral fat deposition, fatty changes in the liver, and metabolic derangements such as insulin resistance and hypertriglyceridemia were evident. These features resemble Dunnigan-type familial partial lipodystrophy, which is a rare condition caused by LMNA gene mutation. These patients shared a common medical history involving HSCT, including conditioning with total body irradiation (TBI). They also received intensive chemotherapy because of multiple metastases (n = 3), relapse (n = 3), and repetitive HSCT (n = 3). We propose HSCT as a new etiology for acquired partial lipodystrophy and recommend that patients who undergo HSCT with TBI and intensive chemotherapy early in their lives must receive careful observation for the possible development of lipodystrophy and metabolic complications.