An in-frame deletion at the polymerase active site of POLD1 causes a multisystem disorder with lipodystrophy

DNA polymerase δ, whose catalytic subunit is encoded by POLD1, is responsible for lagging-strand DNA synthesis during DNA replication. It carries out this synthesis with high fidelity owing to its intrinsic 3'- to 5'-exonuclease activity, which confers proofreading ability. Missense mutations affecting the exonuclease domain of POLD1 have recently been shown to predispose to colorectal and endometrial cancers. Here we report a recurring heterozygous single-codon deletion in POLD1 affecting the polymerase active site that abolishes DNA polymerase activity but only mildly impairs 3'- to 5'-exonuclease activity. This mutation causes a distinct multisystem disorder that includes subcutaneous lipodystrophy, deafness, mandibular hypoplasia and hypogonadism in males. This discovery suggests that perturbing the function of the ubiquitously expressed POLD1 polymerase has unexpectedly tissue-specific effects in humans and argues for an important role for POLD1 function in adipose tissue homeostasis.

The liver diseases of lipodystrophy: the long-term effect of leptin treatment

BACKGROUND & AIMS

Lipodystrophies are hypoleptinemic conditions characterized by fat loss, severe insulin resistance, hypertriglyceridemia, and ectopic fat accumulation. Non-alcoholic fatty liver disease (NAFLD) and steatohepatitis (NASH) are also features of this condition. We studied the spectrum of liver disease in lipodystrophy and the effects of leptin replacement.

METHODS

This was an open-label, prospective study of leptin therapy in patients with inherited and acquired lipodystrophy at the National Institutes of Health. Liver biopsies were performed at baseline (N=50) and after leptin replacement (N=27). NASH activity was assessed using the NASH Clinical Research Network (CRN) scoring system. Fasting blood glucose, triglyceride, hemoglobin A1c and liver enzymes were measured at baseline and at the time of the final liver biopsy.

RESULTS

In leptin-treated patients, 86% met criteria for NASH at baseline, while only 33% had NASH after leptin replacement for 25.8 ± 3.7 months (mean ± SE, p=0.0003). There were significant improvements in steatosis grade (reduction of mean score from 1.8 to 0.9) and ballooning injury scores (from 1.2 to 0.4), with a 44.2% reduction in mean NAFLD activity score (p<0.0001). Patients who already had fibrosis remained stable on leptin replacement. We observed significant improvement in metabolic profile, ALT and AST. In addition to NASH, four patients with acquired generalized lipodystrophy (AGL) had autoimmune hepatitis.

CONCLUSIONS

The fundamental liver disease of lipodystrophy is NASH, although autoimmune hepatitis was observed in some patients with AGL. Leptin appears to be a highly effective therapy for NASH in hypoleptinemic lipodystrophic patients.

Cholic acid for hepatic steatosis in patients with lipodystrophy: a randomized, controlled trial

OBJECTIVE

Hepatic steatosis is a common complication in patients with lipodystrophies and can lead to cirrhosis. There is no proven effective therapy for hepatic steatosis, but cholic acid (CA), a farnesoid X receptor agonist, has previously been shown to reduce hepatic triglyceride (TG) content in mice and serum TG in humans. Our objective was to assess clinical efficacy and tolerability of CA therapy in patients with lipodystrophy and hepatic steatosis.

DESIGN

A randomized, double-blind, placebo-controlled, crossover study.

METHODS

Eighteen patients with genetic or autoimmune lipodystrophies and elevated hepatic TG content participated in the study. The intervention was CA (15 mg/kg per day) compared with placebo for a period of 6 months each. Hepatic TG content, the primary outcome variable, was measured with (1)H magnetic resonance spectroscopy at baseline and at 3 and 6 months during each study period. Levels of serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), gamma-glutamyl transpeptidase (GGT), and TG were secondary end points of the study.

RESULTS

Compared with placebo, CA did not reduce (median (interquartile range) hepatic TG content (14.8% (9.4-19.0%) vs 15.9% (10.5-26.5%) respectively; P=0.42) or serum TG ((340 mg/dl (233-433 mg/dl) vs 390 mg/dl (233-595 mg/dl) respectively; P=0.45)). CA therapy also did not change AST, ALT, or GGT levels. Two patients developed diarrhea and excessive flatus while taking CA and these symptoms resolved after reducing the dose of CA.

CONCLUSION

CA was well tolerated but did not reduce hepatic TG content in patients with lipodystrophy.

Human congenital perilipin deficiency and insulin resistance

Lipid droplets (LDs) can form in all eukaryotic cells, but white adipocytes are uniquely adapted to store energy as neutral lipid within a large unilocular LD. Non-esterified fatty acids can then be released from the LD store by lipases for use in oxidative tissues. Perilipin was the first mammalian LD protein to be identified in adipocytes where it plays a key role in co-ordinating access of lipases to the core triacylglycerol. We recently identified the first human loss-of-function mutations in PLIN1 in patients with a novel form of familial partial lipodystrophy, severe insulin resistance, diabetes, dyslipidaemia and fatty liver. Adipose tissue samples from affected patients revealed remarkably similar features to those previously observed in samples from obese insulin resistant patients, namely macrophage infiltration and fibrosis. Cellular mechanistic studies suggest that the mutations lead to increased basal lipolysis, which is likely to be a major factor in the subsequent inflammatory response. Perilipin is almost exclusively expressed in white adipocytes, so the serious metabolic sequelae observed in these patients suggest that primary defects in adipose tissue can lead to all the typical features seen in patients with the metabolic syndrome. They also suggest that lipolytic inhibitors may be therapeutically useful in these patients.

[Therapy resistant diabetes mellitus and lipodystrophy: leptin therapy leads to improvement]

Lipodystrophy is a congenital or acquired disorder characterized by complete or partial absence of subcutaneous fat tissue, often accompanied by insulin resistance, diabetes mellitus (DM), hypertriglyceridemia and hepatic steatosis. A decrease in both number and function of adipocytes leads to ectopic fat depositions and decreased production of adipokines such as leptin. We present 2 patients with inadequately regulated DM, hypertriglyceridemia and hepatic steatosis who were eventually diagnosed with lipodystrophy: 1 with congenital generalized lipodystrophy (Berardinelli-Seip syndrome) and 1 with congenital partial lipodystrophy (Dunnigan syndrome). Both received recombinant human leptin therapy (methionylleptin, available on a compassionate-use basis). This resulted in improved plasma levels of triglyceride, glucose and HbA1c and a decrease in liver size. In addition, hepatic triglyceride content decreased from 19.3% to 1.3% in the first patient and from 20.6% to 12.4% in the second. Leptin therapy is an effective and safe treatment for therapy-resistant diabetes and hypertriglyceridemia in patients with congenital lipodystrophy.

Indices of body fat distribution for assessment of lipodysthrophy in people living with HIV/AIDS

BACKGROUND

Metabolic and morphological changes associated with excessive abdominal fat, after the introduction of Antiretroviral Therapy, increase the risk of cardiovascular disease in people living with HIV/AIDS(PLWHA). Accurate methods for body composition analysis are expensive and the use of anthropometric indices is an alternative. However the investigations about this subject in PLWHA are rare, making this research very important for clinical purpose and to advance scientific knowledge. The aim of this study is to correlate results of anthropometric indices of evaluation of body fat distribution with the results obtained by Dual-energy X-Ray Absorptiometry(DEXA), in people living with HIV/AIDS.

METHODS

The sample was of 67 PLWHA(39 male and 28 female), aged 43.6±7.9 years. Body mass index, conicity index, waist/hip ratio, waist/height ratio and waist/thigh were calculated. Separated by sex, each index/ratio was plotted in a scatter chart with linear regression fit and their respective Pearson correlation coefficients. Analyses were performed using Prism statistical program and significance was set at 5%.

RESULTS

The waist/height ratio presented the highest correlation coefficient, for both male (r=0.80, p<0.001) and female (r=0.87, p <001), while the lowest were in the waist/thigh also for both: male group (r=0.58, p<0.001) and female group (r=0.03, p=0.86). The other indices also showed significant positive correlation with DEXA.

CONCLUSION

Anthropometric indices, especially waist/height ratio may be a good alternative way to be used for evaluating the distribution of fat in the abdominal region of adults living with HIV/ADIS.

Myostatin inhibition prevents diabetes and hyperphagia in a mouse model of lipodystrophy

Lipodystrophies are characterized by a loss of white adipose tissue, which causes ectopic lipid deposition, peripheral insulin resistance, reduced adipokine levels, and increased food intake (hyperphagia). The growth factor myostatin (MSTN) negatively regulates skeletal muscle growth, and mice with MSTN inhibition have reduced adiposity and improved insulin sensitivity. MSTN inhibition may therefore be efficacious in ameliorating diabetes. To test this hypothesis, we inhibited MSTN signaling in a diabetic model of generalized lipodystrophy to analyze its effects on glucose metabolism separate from effects on adipose mass. A-ZIP/F1 lipodystrophic mice were crossed to mice expressing a dominant-negative MSTN receptor (activin receptor type IIB) in muscle. MSTN inhibition in A-ZIP/F1 mice reduced blood glucose, serum insulin, triglyceride levels, and the rate of triglyceride synthesis, and improved insulin sensitivity. Unexpectedly, hyperphagia was normalized by MSTN inhibition in muscle. Blood glucose and hyperphagia were reduced in double mutants independent of the adipokine leptin. These results show that the effect of MSTN inhibition on insulin sensitivity is not secondary to an effect on adipose mass and that MSTN inhibition may be an effective treatment for diabetes. These results further suggest that muscle may play a heretofore unappreciated role in regulating food intake.

GH response to GHRH plus arginine is impaired in lipoatrophic women with human immunodeficiency virus compared with controls

OBJECTIVE

GH secretion is impaired in lipodystrophic human immunodeficiency virus (HIV) patients and inversely related to lipodystrophy-related fat redistribution in men. Less is known about the underlying mechanisms involved in reduced GH secretion in HIV-infected women.

DESIGN

A case-control, cross-sectional study comparing GH/IGF1 status, body composition, and metabolic parameters in 92 nonobese women with HIV-related lipodystrophy and 63 healthy controls matched for age, ethnicity, sex, and body mass index (BMI).

METHODS

GH, IGF1, IGF binding protein 3 (IGFBP3), GH after GHRH plus arginine (GHRH+Arg), several metabolic variables, and body composition were evaluated.

RESULTS

GH response to GHRH+Arg was lower in HIV-infected females than in controls. Using a cutoff of peak GH ≤ 7.5 μg/l, 20.6% of HIV-infected females demonstrated reduced peak GH response after GHRH+Arg. In contrast, none of the control subjects demonstrated a peak GH response ≤ 7.5 μg/l. Bone mineral density (BMD), quality of life, IGF1, and IGFBP3 were lowest in the HIV-infected females with a GH peak ≤ 7.5 μg/l. BMI was the main predictive factor of GH peak in stepwise multiregression analysis followed by age, with a less significant effect of visceral fat in the HIV-infected females.

CONCLUSIONS

This study establishes that i) GH response to GHRH+Arg is lower in lipoatrophic HIV-infected women than in healthy matched controls, ii) BMI more than visceral adipose tissue or trunk fat influences GH peak in this population, and iii) HIV-infected women with a GH peak below or equal to 7.5 μg/l demonstrate reduced IGF1, IGFBP3, BMD, and quality of life.

Insulin resistance is a sufficient basis for hyperandrogenism in lipodystrophic women with polycystic ovarian syndrome

CONTEXT

The lipodystrophies (LD) are characterized by metabolic abnormalities (insulin resistance, hypertriglyceridemia, and diabetes) and a polycystic ovarian syndrome (PCOS) phenotype. Therapeutic administration of leptin improves insulin sensitivity and the metabolic features.

OBJECTIVE

The objective of the study was to investigate whether the PCOS features are corrected by increasing insulin sensitivity as a function of leptin treatment.

DESIGN

This was a prospective, open-label trial using leptin replacement in various forms of lipodystrophy.

SETTING

The study was performed at the Clinical Center at the National Institutes of Health.

PATIENTS OR OTHER PARTICIPANTS

Twenty-three female patients with LD were enrolled in a leptin replacement trial from 2000 to the present. Different parameters were assessed at baseline and after 1 yr of therapy.

INTERVENTION(S)

Patients were treated with leptin for at least 1 yr.

MAIN OUTCOME MEASURE(S)

We evaluated free testosterone, SHBG, and IGF-I at baseline and after 1 yr of leptin.

RESULTS

Testosterone levels decreased from 3.05 ±0.6 ng/ml at baseline to 1.7 ±0.3 ng/ml (P = 0.02). SHBG increased from 14.5 ±2 to 25 ±3.5 nmol/liter after 1 yr of leptin therapy. There were no significant changes in the levels of gonadotropins and ovarian size as a result of leptin replacement therapy. IGF-I increased significantly after leptin therapy from 150 ±14 to 195 ±17. There was a significant decrease in triglycerides and glycosylated hemoglobin in the context of reduced insulin requirements.

CONCLUSIONS

In the present study, we show that LD may be a model for the common forms of PCOS and that the endocrine features are corrected by leptin therapy, which reduces insulin resistance.

Underreporting of side effects of standard first-line ART in the routine setting in Blantyre, Malawi

INTRODUCTION

In the Malawi ART programme, 92% of 250,000 patients are using the standard first-line regime of stavudine-lamivudine-nevaripine. National ART reports indicate <4% experience ART side effects, much less than expected from literature.

METHODS

We interviewed adult patients on standard first-line ART for at least one year, after routine visits to an urban clinic in Blantyre, Malawi. We determined the prevalence of symptoms that are common side-effects, described discrepancies between symptoms that patients reported to us and those that had been recorded by attending staff as side-effects in the point-of-care electronic monitoring system, and studied factors associated with such discrepancies.

RESULTS

Of 170 participants, 75 (44%) reported at least one symptom, most common were symptoms suggesting peripheral neuropathy (n=57) and lipodystrophy (n=16). Forty-six (66%) symptomatic patients said they reported symptoms to attending ART staff. Side-effects were recorded in the clinic database for just 4 patients. Toxicity recording was too low for meaningful analysis of factors associated with discrepancies between reporting and recording of side-effects. The prevalence of symptoms indicating characteristic side-effects of the standard first-line regimen was 39% based on interviews, and 2% in the electronic monitoring system.

CONCLUSION

There was gross under-recording of side-effects in this setting, mainly due to not recording by ART staff. Pressure of work and insufficient perceived benefit of side-effect recording are suspected causes. Local and national ART reports do not reflect the true toxicity of the standard first line regimen.

Embryonic senescence and laminopathies in a progeroid zebrafish model

Background

Mutations that disrupt the conversion of prelamin A to mature lamin A cause the rare genetic disorder Hutchinson-Gilford progeria syndrome and a group of laminopathies. Our understanding of how A-type lamins function in vivo during early vertebrate development through aging remains limited, and would benefit from a suitable experimental model. The zebrafish has proven to be a tractable model organism for studying both development and aging at the molecular genetic level. Zebrafish show an array of senescence symptoms resembling those in humans, which can be targeted to specific aging pathways conserved in vertebrates. However, no zebrafish models bearing human premature senescence currently exist.

Principal Findings

We describe the induction of embryonic senescence and laminopathies in zebrafish harboring disturbed expressions of the lamin A gene (LMNA). Impairments in these fish arise in the skin, muscle and adipose tissue, and sometimes in the cartilage. Reduced function of lamin A/C by translational blocking of the LMNA gene induced apoptosis, cell-cycle arrest, and craniofacial abnormalities/cartilage defects. By contrast, induced cryptic splicing of LMNA, which generates the deletion of 8 amino acid residues lamin A (zlamin A-Δ8), showed embryonic senescence and S-phase accumulation/arrest. Interestingly, the abnormal muscle and lipodystrophic phenotypes were common in both cases. Hence, both decrease-of-function of lamin A/C and gain-of-function of aberrant lamin A protein induced laminopathies that are associated with mesenchymal cell lineages during zebrafish early development. Visualization of individual cells expressing zebrafish progerin (zProgerin/zlamin A-Δ37) fused to green fluorescent protein further revealed misshapen nuclear membrane. A farnesyltransferase inhibitor reduced these nuclear abnormalities and significantly prevented embryonic senescence and muscle fiber damage induced by zProgerin. Importantly, the adult Progerin fish survived and remained fertile with relatively mild phenotypes only, but had shortened lifespan with obvious distortion of body shape.

Conclusion

We generated new zebrafish models for a human premature aging disorder, and further demonstrated the utility for studying laminopathies. Premature aging could also be modeled in zebrafish embryos. This genetic model may thus provide a new platform for future drug screening as well as genetic analyses aimed at identifying modifier genes that influence not only progeria and laminopathies but also other age-associated human diseases common in vertebrates.

Carotid intima media thickness, inflammatory markers, and endothelial activation markers in HIV Patients with lipoatrophy increased at 48 weeks regardless of use of rosiglitazone or placebo

Rosiglitazone may be useful for the treatment of antiretroviral therapy-associated lipoatrophy, but an association with cardiovascular disease (CVD) has been questioned in diabetics. We evaluated rosiglitazone's effect on surrogate markers of CVD in HIV-infected individuals with lipoatrophy. HIV(+) patients with lipoatrophy on thymidine-sparing regimens were randomized to rosiglitazone vs. placebo for 48 weeks. We serially assessed carotid IMT, fasting metabolic profiles, tumor necrosis factor (TNF)-α, soluble receptors (sTNFRI and II), interleukin (IL)-6, high-sensitivity C-reactive protein (hsCRP), myeloperoxidase (MPO), and endothelial activation markers [von Willebrand factor (vWF), soluble intercellular cell adhesion molecules-1 (sICAM-1), and vascular cell adhesion molecules-1 (sVCAM-1)]. Seventy-one subjects enrolled: 17% were female and 51%were white. Baseline characteristics were similar between groups except for higher total cholesterol in the placebo group (p = 0.04). At 48 weeks, common carotid artery (CCA) IMT changed significantly (p ≤ 0.05) within but not between the groups (p = 0.36): the median (IQR) increase was 0.10 (0.05, 0.25) mm and 0.15 (0, 0.25) mm in the rosiglitazone and placebo groups, respectively. hsCRP, sTNFRI and II, sVCAM-1, and vWF changed significantly (p ≤ 0.02) within but not between groups. Total cholesterol increased significantly in the rosiglitazone group (p = 0.008). In our study of virologically controlled subjects with lipoatrophy, rosiglitazone did not independently increase carotid IMT, endothelial activation, and inflammatory cytokines.

Bodies in mutation: understanding lipodystrophy among women living with HIV/AIDS

Over the past decade, the lipodystrophy syndrome has become one of the biggest challenges in the field dof HIV/AIDS. However, few qualitative studies have examined how lipodystrophy affects the lives of people living with HIV/AIDS by reconfiguring their bodies in unexpected ways. The main objective of this qualitative study was to explore and describe the transformation process that women experience following the onset of lipodystrophy. The data was collected using semistructured interviews and was then analyzed following the principles of grounded theory. The purpose of this article is to synthesize our research findings with a particular emphasis on the basis social process (BSP) that emerged during the data analysis, namely, the bodily transformation process. Our objective is to highlight the experiences shared by women who go through this bodily transformation process and the challenges they face as they move progressively from one bodily state to another. Following the presentation of the bodily transformation process, we will discuss the implications of our findings for the advancement of nursing knowledge as well as the development of theories specific to the situations of people who suffer from chronic conditions and undergo a physical transformation as a result of medical treatment. Lastly, we will address the implications of our findings for nursing research and nursing practice.

Clinical approach to the patient with diabetes mellitus and very high insulin requirements

A number of patients with diabetes require very high (> 2 Ukg⁻¹ day⁻¹), or extremely high (> 3 Ukg⁻¹ day⁻¹), insulin doses for the management of their hyperglycemia. Unfortunately, many of the physicians who treat these patients limit themselves to prescribing ever higher doses of insulin, without questioning why. Furthermore, when the insulin requirements get to be extreme, demanding an explanation, clinicians are frequently lost in a sea of literature where there is not a single paper dealing with this problem systematically. A systematic approach to the evaluation of these patients is necessary to facilitate an appropriate diagnosis, select the most reasonable therapy, and hopefully improve the long-term outcome of these patients. This manuscript intends to provide the clinician with a review of the literature pertinent for the differential diagnosis, work-up, and management of these patients. We will review the definitions of insulin sensitivity during normality, the various degrees or categories of insulin resistance, and the expected insulin requirements during each of these states. Subsequently, we propose a simple alphabetic mnemonic approach to help remember the differential diagnosis, and a clinical algorithm to help guide the work-up of these patients. Lastly, we briefly discuss general management considerations in these conditions.

A novel syndrome of mandibular hypoplasia, deafness, and progeroid features associated with lipodystrophy, undescended testes, and male hypogonadism

CONTEXT

Mandibuloacral dysplasia (MAD) is an autosomal recessive progeroid disorder associated with type A (partial) or B (generalized) lipodystrophy and is due to mutations in lamin A/C (LMNA) or zinc metalloproteinase (ZMPSTE24) genes.

OBJECTIVE

The objective of the study was to report a novel syndrome with some overlapping features with MAD.

RESULTS

We report seven patients with mandibular hypoplasia, deafness, progeroid features (MDP), and associated lipodystrophy. These patients have similar features to MAD patients such as hypoplastic mandible, beaked nose, stiff joints, and sclerodermatous skin. However, the patients did not harbor any disease causing variants in LMNA or ZMPSTE24 and showed distinct characteristics such as sensorineural hearing loss and absence of clavicular hypoplasia and acroosteolysis. All males with MDP had undescended testes and were hypogonadal. One adult female showed lack of breast development. Skinfold thickness, dual-energy X-ray absorptiometry and whole-body magnetic resonance imaging for body fat distribution revealed a lack of lipodystrophy in a prepubertal female but a progressive loss of sc fat presenting with partial lipodystrophy in young adults and generalized lipodystrophy in older patients.

CONCLUSIONS

Patients with MDP syndrome have a few overlapping but some distinct clinical features as compared with MAD, suggesting that it is a novel syndrome. The molecular basis of MDP syndrome remains to be elucidated.

An autosomal recessive syndrome of joint contractures, muscular atrophy, microcytic anemia, and panniculitis-associated lipodystrophy

CONTEXT

Genetic lipodystrophies are rare disorders characterized by partial or complete loss of adipose tissue and predisposition to insulin resistance and its complications such as diabetes mellitus, hypertriglyceridemia, hepatic steatosis, acanthosis nigricans, and polycystic ovarian syndrome.

OBJECTIVE

The objective of the study was to report a novel autosomal recessive lipodystrophy syndrome.

RESULTS

We report the detailed phenotype of two males and one female patient, 26-34 yr old, belonging to two pedigrees with an autosomal recessive syndrome presenting with childhood-onset lipodystrophy, muscle atrophy, severe joint contractures, erythematous skin lesions, and microcytic anemia. Other variable clinical features include hypergammaglobulinemia, hepatosplenomegaly, generalized seizures, and basal ganglia calcification. None of the patients had diabetes mellitus or acanthosis nigricans. Two had mild hypertriglyceridemia and all had low levels of high-density lipoprotein cholesterol. Skin biopsy of an erythematous nodular skin lesion from one of the patients revealed evidence of panniculitis. The lipodystrophy initially affected the upper body but later became generalized involving abdomen and lower extremities as well.

CONCLUSIONS

We conclude that these patients represent a novel autoinflammatory syndrome resulting in joint contractures, muscle atrophy, microcytic anemia, and panniculitis-induced lipodystrophy. The molecular genetic basis of this disorder remains to be elucidated.

Cardiomyopathy in congenital and acquired generalized lipodystrophy: a clinical assessment

Lipodystrophy is a rare disorder characterized by loss of adipose tissue and low leptin levels. This condition is characterized by severe dyslipidemia, insulin resistance, diabetes mellitus, and steatohepatitis. Another phenotypic feature that occurs with considerable frequency in generalized lipodystrophy is cardiomyopathy. We report here the cardiac findings in a cohort of patients with generalized congenital and acquired lipodystrophy, and present a literature review of the cardiac findings in patients with generalized lipodystrophy. We studied 44 patients with generalized congenital and acquired lipodystrophy, most of them enrolled in a clinical trial of leptin therapy. Patients underwent electrocardiograms and transthoracic echocardiograms to evaluate their cardiac status. We followed these patients for an extended time period, some of them up to 8 years. Evaluation of our cohort of patients with generalized lipodystrophy shows that cardiomyopathy is a frequent finding in this population. Most of our patients had hypertrophic cardiomyopathy, and only a small number had features of dilated cardiomyopathy. Hypertrophic cardiomyopathy was more frequent in patients with seipin mutation, a finding consistent with the literature. The underlying mechanism for cardiomyopathy in lipodystrophy is not clear. Extreme insulin resistance and the possibility of a "lipotoxic cardiomyopathy" should be entertained as possible explanations.

Insulin absorption from lipodystrophic areas: a (neglected) source of trouble for insulin therapy?

The experienced clinical diabetologist first checks the skin at the area where the patient usually injects his insulin when he sees widely fluctuating blood glucose levels in the diary of the patient. He knows that insulin absorption from skin with lipodystrophic changes is irregular. However, our scientific knowledge about why this is the case is very limited. Most probably, the number of blood vessels near the insulin depot in the subcutaneous tissue varies depending on the nature of the lipodystrophic changes, or the structural changes in this tissue hamper the diffusion of insulin. Not only is our knowledge about the number of patients who exhibit such changes very limited, but also our understanding why such changes show up in certain patients and not in others is minimal. More practically important, we also have few quantitative studies investigating the impact of this diabetes-related complication on insulin absorption/insulin action; however, it is not difficult to run such studies in practice. Nevertheless, it is impressive to see how often metabolic control improves considerably once the patients apply the insulin into other skin areas.

Acquired reactive perforating collagenosis in an insulin dependent diabetes mellitus patient

Acquired reactive perforating collagenosis is a skin disorder characterised by the transepidermal elimination of altered collagen through the epidermis. Two distinct forms exist; an inherited form that present in childhood resulting from superficial trauma, scratching, insect bite, etc., and an acquired form that usually develops de novo in patients suffering from many chronic systemic and auto-immune diseases without any minor injury. Here a 36-year-old, insulin dependent diabetes mellitus patient with acquired variety of reactive perforating collagenosis and lipodystrophy at the sites of insulin injection sites is presented. Isotretinoin 0.1% cream was advised but with little improvement.

Inherited lipodystrophies and hypertriglyceridemia

PURPOSE OF REVIEW

Inherited lipodystrophies are rare autosomal recessive and dominant disorders characterized by selective, but variable, loss of adipose tissue. Marked hypertriglyceridemia is a common feature of these disorders and highlights the role of adipose tissue in lipid homeostasis. In the last decade, advances have been made in elucidating the molecular basis of many inherited lipodystrophies. We review the new insights in the pathophysiology and treatment of these disorders based on the current understanding of the biologic role of these lipodystrophy genes.

RECENT FINDINGS

Eight different genetic loci, including 1-acylglycerol-3-phosphate-O-acyltransferase 2, Berardinelli-Seip congenital lipodystrophy 2, caveolin 1, lamin A/C, peroxisome proliferator-activated receptor gamma, v-AKT murine thymoma oncogene homolog 2, zinc metalloprotease and lipase maturation factor 1 have been described linked to different lipodystrophy syndromes. Mutations in these genes may cause fat loss and dyslipidemia through multiple mechanisms, which remain fully elucidated; however, they may involve defects in development and differentiation of adipocytes, and premature death and apoptosis of adipocytes. Hypertriglyceridemia is a consequence of increased VLDL synthesis from the liver, which is also loaded by ectopic triglyceride deposition, reduced clearance of triglyceride-rich lipoproteins or both. A recent study in mice with Agpat2 deficiency reports marked reduction in serum triglyceride upon feeding a fat-free diet, which suggests that low-fat diets are likely to be beneficial in lipodystrophic patients. Leptin replacement therapy is also a promising therapeutic option for lipodystrophic patients with hypoleptinemia.

SUMMARY

Inherited lipodystrophies are an important cause for monogenic hypertriglyceridemia and serve to highlight the role of adipocytes in maintaining normolipidemia.

Zidovudine/lamivudine for HIV-1 infection contributes to limb fat loss

Background

Lipoatrophy is known to be associated with stavudine as part of the treatment for HIV infection, but it is less clear if this serious side effect is also related to other nucleoside reverse transcriptase inhibitors like zidovudine. We aimed to determine whether zidovudine-sparing first-line antiretroviral therapy would lead to less lipoatrophy and other metabolic changes than zidovudine-containing therapy.

Methodology/Principal Findings

Fifty antiretroviral therapy-naïve HIV-1 infected men with an indication to start antiretroviral therapy were included in a randomized single blinded clinical trial. Randomisation was between zidovudine-containing therapy (zidovudine/lamivudine+lopinavir/ritonavir) and zidovudine-sparing therapy (nevirapine+lopinavir/ritonavir). Main outcome measures were body composition assessed by computed tomography and dual-energy X-ray absorptiometry scan and lipid profile before and after 3, 12, 24 months of antiretroviral therapy. In the zidovudine/lamivudine+lopinavir/ritonavir group, from 3 months onward limb fat decreased progressively by 684±293 grams (estimated mean±standard error of the mean)(p = 0.02) up to 24 months whereas abdominal fat increased, but exclusively in the visceral compartment (+21.9±8.1 cm², p = 0.008)). In contrast, in the nevirapine+lopinavir/ritonavir group, a generalized increase in fat mass was observed. After 24 months no significant differences in high density lipoprotein and total/high density lipoprotein cholesterol ratio were found between both treatment groups, but total and low density lipoprotein cholesterol levels were higher in the nevirapine+lopinavir/ritonavir group (6.1±0.2 versus 5.3±0.2 and 3.6±0.1 versus 2.8±0.1 mmol/l respectively, p<0.05). Virologic response and safety were comparable in both groups.

Conclusions/Significance

Zidovudine/lamivudine+lopinavir/ritonavir, but not nevirapine+lopinavir/ritonavir in antiretroviral therapy-naïve patients, is associated with lipoatrophy and greater relative intraabdominal lipohypertrophy, suggesting that zidovudine/lamivudine contributes to both these features of lipodystrophy. These findings support to no longer consider zidovudine/lamivudine as one of the preferred possible components of first-line antiretroviral therapy where alternative treatments are available.

Trial Registration

ClinicalTrials.gov NCT 00122226