Severe mandibuloacral dysplasia-associated lipodystrophy and progeria in a young girl with a novel homozygous Arg527Cys LMNA mutation

CONTEXT

Mandibuloacral dysplasia (MAD) is a rare autosomal recessive progeroid syndrome due to mutations in genes encoding nuclear lamina proteins, lamins A/C (LMNA) or prelamin A processing enzyme, and zinc metalloproteinase (ZMPSTE24).

OBJECTIVE

The aim of the study was to investigate the underlying genetic and molecular basis of the phenotype of a 7-yr-old girl with MAD belonging to a consanguineous pedigree and with severe progeroid features and lipodystrophy.

DESIGN AND PATIENT

The patient developed mandibular hypoplasia during infancy and joint stiffness, skin thinning, and mottled hyperpigmentation at 15 months. Progressive clavicular hypoplasia, acroosteolysis, and severe loss of hair from the temporal and occipital areas were noticed at 3 yr. At 5 yr, cranial sutures were still open and lipodystrophy of the limbs was prominent. GH therapy from the ages of 3-7 yr did not improve the short stature. Severe joint contractures resulted in abnormal posture and decreased mobility. We studied her skin fibroblasts for nuclear morphology and immunoblotting and determined the in vitro effects of various pharmacological interventions on fibroblasts.

RESULTS

LMNA gene sequencing revealed a homozygous missense mutation, c.1579C>T, p.Arg527Cys. Immunoblotting of skin fibroblast lysate with lamin A/C antibody revealed no prelamin A accumulation. Immunofluorescence staining of the nuclei for lamin A/C in fibroblasts revealed marked nuclear morphological abnormalities. This abnormal phenotype could not be rescued with inhibitors of farnesyl transferase, geranylgeranyl transferase, or histone deacetylase.

CONCLUSION

Severe progeroid features in MAD could result from LMNA mutation, which does not lead to accumulation of prenylated lamin A or prelamin A.

HIV-associated facial lipoatrophy--review of current therapy options

Highly active antiretroviral therapy (HAART) has dramatically improved the life expectancy for HIV-infected patients. Long-term complications of both HIV-infection and antiretroviral agents are therefore of increasing concern. Facial lipoatrophy (FLA) is a stigmatizing complication associated with sever social impact and a reduced quality of life for the patient. - We aimed to review the treatment options of HIV-associated FLA. The current treatments available for treating FLA are limited and can be classified in three main categories: I. Medial therapy, II. Injectables with different duration of effect, and III. Surgical treatment options. Medical therapy can provide a small benefit but improvement is, at best, slow and partial. Injectables can yield marked results but are costly, time consuming and may be associated with complications such as granuloma formation. Surgical options such as augmentation with specially designed silicone implants may be of benefit for severe cases of FLA, however, they are associated with higher surgical complications and do not account for the dynamic process of FLA. - To summarize, until today no ideal strategies for treatment of HIV-associated FLA are available, and new therapies are strongly required. heart disease.

Type 1 diabetes associated with acquired generalized lipodystrophy and insulin resistance: the effect of long-term leptin therapy

CONTEXT

Acquired generalized lipodystrophy (AGL) is marked by severe insulin resistance and hypertriglyceridemia. Rarely, AGL and type 1 diabetes (T1D) coexist.

OBJECTIVE

Our objective was to describe the response to leptin therapy in patients with coexisting AGL and T1D and to document the autoimmune diseases associated with AGL.

DESIGN AND SETTING

We conducted an open-label prospective study at the Clinical Research Center of the National Institutes of Health.

PATIENTS

Participants included 50 patients with generalized or partial lipodystrophy (acquired or congenital); two patients had both AGL and T1D.

INTERVENTION

Patients were treated with 12 months of recombinant human leptin administration to achieve high-normal serum concentrations.

RESULTS

Two patients had both AGL and T1D. The first was diagnosed with T1D at age 8 yr. Beginning at age 11 yr, he developed generalized lipodystrophy, elevated transaminases, and poor glycemic control [hemoglobin A 1c (HbA 1c) 10.7%] despite markedly increased insulin requirements (3.3-5 U/kg.d). Further evaluation revealed hypoleptinemia and hypertriglyceridemia. At age 15 yr, leptin therapy was initiated, and after 1 yr, his insulin requirements fell to 1 U/kg.d, his glycemic control improved (HbA 1c 8.4%), and both his triglycerides and transaminases normalized. The second patient developed concurrent AGL and T1D at age 6 yr. Despite insulin doses of up to 32 U/kg.d, she developed poor glycemic control (HbA 1c 10.6%), hypertriglyceridemia (2984 mg/dl), elevated transaminases, and nonalcoholic steatohepatitis. At age 13 yr, leptin therapy was started, and after 1 yr, her glycemic control improved (HbA 1c 7.3%) and her insulin requirements decreased (17 U/kg.d). Her triglycerides remained elevated but were improved (441 mg/dl).

CONCLUSIONS

Long-term recombinant leptin therapy is effective in treating the insulin resistance of patients with the unusual combination of T1D and AGL.

Human subcutaneous adipose tissue LPIN1 expression in obesity, type 2 diabetes mellitus, and human immunodeficiency virus--associated lipodystrophy syndrome

The aim of this study was to analyze LPIN1 adipose tissue gene expression levels in 3 clinical insulin-resistant conditions-obesity, type 2 diabetes mellitus, and human immunodeficiency virus (HIV)-associated lipodystrophy-and its relationship with adipogenic and inflammatory markers. Subcutaneous adipose tissue samples were obtained from 2 cohorts: 98 subjects with different degrees of adiposity and with or without the presence of type 2 diabetes mellitus and 37 HIV-infected patients. Real-time polymerase chain reaction was used to measure gene expression of LPIN1 and adipogenic (PPARgamma, SREBP1c) and inflammatory markers (IL6, TNFalpha, TNFR1, and TNFR2). LPIN1 messenger RNA expression levels were significantly lower in the obese group (P = .002), were similar in type 2 diabetes mellitus patients and control subjects (P = .211), and were significantly higher in HIV-infected patients (P < .001). LPIN1 messenger RNA levels positively correlated with insulin sensitivity in all subjects. Moreover, an inverse correlation with proinflammatory cytokines was observed.

Dual Modulation of Vascular Function by Perivascular Adipose Tissue and Its Potential Correlation with Adiposity/Lipoatrophy-Related Vascular Dysfunction

Almost every systemic vessel is surrounded by a layer of perivascular adipose tissue (PVAT), which had been mainly considered as a mechanical support for vasculature. However, recent advances have revealed that PVAT is an active player in controlling vessel function. PVAT releases relaxation factor(s) with unknown chemical identity (named perivascular adipocyte-derived relaxation factor, PVRF) that attenuates vasoconstriction to various agonists including phenylephrine, serotonin, angiotensin II, and U 46619 (a thromboxane A(2) mimic), through activation of K(+) channels. PVAT also promotes vasoconstriction to perivascular nerve stimulation by producing vasoconstrictor or facilitator (named perivascular adipocyte-derived constricting factor, PVCF), which includes superoxide and was mediated through activation of tyrosine kinase and MAPK/ERK pathways. Therefore, PVAT has a dual regulatory role in modulating vessel function, attenuating vasoconstriction to agonists by PVRF and promoting constriction to perivascular nerve excitation by PVCF. In vivo, normal amount of PVAT (total body fat as well) is likely to be important in maintaining the homeostasis of vascular tone and blood pressure, since lipoatrophic mice developed hypertension. On the other end, excessive accumulation of body fat (obesity) impaired PVRF production/action, despite an increase in the amount of PVAT. In spontaneously hypertensive rats, an animal model of hypertension without obesity, the ability of PVAT to attenuate vasoconstriction to agonists was reduced, and treatment with atorvastatin improved PVAT function. PVAT, vasodilating and constricting factors of PVAT origin, and signalling pathways of these factors may represent new targets for developing new strategies to treat vascular disorders associated with abnormal adiposity.

The basis and management of metabolic abnormalities associated with cardiovascular risk in human immunodeficiency virus infection and its treatment

The high global prevalence of human immunodeficiency virus (HIV) infection has been associated with high morbidity and mortality. The advent of highly active antiretroviral therapy (HAART) has, however, dramatically increased survival of patients infected with HIV. These patients now survive to develop metabolic complications of HIV infection and its treatment, including increased predisposition to atherosclerotic disease. HIV infection is normally associated with hypocholesterolaemia, hypertriglyceridaemia, low plasma HDL-cholesterol as well as alterations in other cardiovascular risk factors including inflammatory markers, clotting factors, homocysteine, apolipoproteins, lipoprotein (a), oxidative stress and non-esterified fatty acids. The use of HAART is, in particular, associated with dyslipidaemia and lipodystrophy with underlying insulin resistance and associated glucose intolerance. This article explores the metabolic abnormalities associated with increased cardiovascular risk that occur in HIV infection before and after antiretroviral therapy. The laboratory investigation and clinical management of HIV-associated dyslipidaemia and lipodystrophy will be discussed.

Association between hepatitis C virus coinfection and regional adipose tissue volume in HIV-infected men and women

OBJECTIVE

Coinfection with hepatitis C virus (HCV) is reported to be associated with a higher prevalence of lipodystrophy than HIV infection alone. We examine the association between HCV and adipose tissue volume in HIV-infected men and women.

METHODS

Cross-sectional analysis of HIV-infected subjects from the study of Fat Redistribution and Metabolic Change in HIV Infection. MRI measured regional adipose tissue volume. Detectable HCV RNA defined HCV infection.

RESULTS

Twenty percent of 792 men and 26% of 329 women were HIV/HCV-coinfected. HIV/HCV-coinfected and HIV-monoinfected women had similar amounts of subcutaneous adipose tissue (SAT) in the leg, lower trunk, upper trunk, and arm and similar amounts of visceral adipose tissue (VAT). Similar findings were seen in men, except in the leg and VAT. After adjustment, HCV infection remained associated with more leg fat in men (12.2%, 95% confidence interval [CI]: 0.3 to 25.3; P = 0.043). Among those on stavudine, HIV-monoinfected men had less leg fat (-7% effect per year of stavudine use, 95% CI: -9 to -5; P < 0.001); a weaker association was seen in HIV/HCV-coinfected men (-2% effect, 95% CI: -7 to 3; P = 0.45). Indinavir was associated with less leg fat (-4% in HIV-monoinfected men, 95% CI: -6 to -1; P = 0.002; -5% in HIV/HCV-coinfected men, 95% CI: -11 to 2; P = 0.14).

CONCLUSIONS

Our findings suggest that HIV/HCV coinfection is not associated with less SAT in men and women. HCV infection seems to mitigate the loss of leg fat seen in HIV-infected men on stavudine.

Gastric bypass for insulin resistance due to lipodystrophy

We report a 41-year-old woman with severe insulin resistance due to partial lipodystrophy, who was successfully treated with gastric bypass surgery.

Efficacy and safety of leptin-replacement therapy and possible mechanisms of leptin actions in patients with generalized lipodystrophy

BACKGROUND

Lack of leptin is implicated in insulin resistance and other metabolic abnormalities in generalized lipodystrophy; however, the efficacy, safety, and underlying mechanisms of leptin-replacement therapy in patients with generalized lipodystrophy remain unclear.

METHODS

Seven Japanese patients with generalized lipodystrophy, two acquired and five congenital type, were treated with the physiological replacement dose of recombinant leptin during an initial 4-month hospitalization followed by outpatient follow-up for up to 36 months.

RESULTS

The leptin-replacement therapy with the twice-daily injection dramatically improved fasting glucose (mean +/- SE, 172 +/- 20 to 120 +/- 12 mg/dl, P < 0.05) and triglyceride levels (mean +/- SE, 700 +/- 272 to 260 +/- 98 mg/dl, P < 0.05) within 1 wk. The leptin-replacement therapy reduced insulin resistance evaluated by euglycemic clamp method and augmented insulin secretion at glucose tolerance test with different responses between acquired and congenital types. Improvement of the fatty liver was also observed. The efficacy and safety of the once-daily injection were comparable to those of the twice-daily injection. The leptin-replacement therapy ameliorated macro- and microalbuminuria and showed no deterioration of neuropathy and retinopathy of these patients. The leptin-replacement therapy is beneficial to diabetic complications and lipodystrophic ones. Two patients developed antileptin antibodies but not neutralizing antibodies. The therapy was well tolerated, and its effects were maintained for up to 36 months without any notable adverse effects such as hypoglycemia, high blood pressure, or reduction of bone mineral density.

CONCLUSIONS

The present study demonstrates the efficacy and safety of the long-term leptin-replacement therapy and possible mechanisms of leptin actions in patients with generalized lipodystrophy.

[Etiologic spectrum of mesenteric panniculitis: report of 7 cases]

OBJECTIVE

Mesenteric panniculitis is a rare disorder characterized by nonspecific inflammation and/or necrosis and/or fibrosis in the adipose tissue of the bowel mesentery. Its signification, primary or associated with other diseases, is a subject of controversy.

METHODS

A descriptive and retrospective study of patients with an abdominal CT examination showing features of mesenteric panniculitis and for whom biopsy with immunohistochemical examination was obtained in all cases.

RESULTS

Seven patients were enrolled (4 men and 3 women) with a median age of 62,1 years. None of the patients without an identified etiology had a history of abdominal surgery. An associated disease was identified in 4 cases: breast cancer (1), non-Hodgkin's lymphoma based on peripheric lymph nodes biopsy (2) and cryoglobulinemic vascularitis based on renal biopsy (1). In the 3 remaining cases, isolated mesenteric panniculitis was the only abnormality despite thorough imaging and pathologic investigations.

CONCLUSION

Except an obvious malignancy context or a history of abdominal surgery, a pathologic examination of the mesenteric panniculitis lesions is necessary, especially to eliminate another mesenteric disorder. Mesenteric panniculitis is often associated with lymphoma.

TH9507: an experimental treatment for lipodystrophy

As the use of highly active antiretroviral therapy (HAART) became widespread, HIV positive individuals and their physicians began to notice changes in body fat distribution, with excess fat or fat loss noted in different areas. These body shape changes are sometimes accompanied by metabolic abnormalities, such as insulin resistance and elevated blood fats. Collectively, these changes are known as lipodystrophy syndrome. Treatment options for lipodystrophy are somewhat limited. Growth hormone has been used with success in clinical trials to reduce visceral adipose tissue, fat that collects around the abdominal organs. A new product, TH9507, a synthetic growth hormone releasing hormone analog made by the Canadian pharmaceutical company Theratechnologies, is currently showing promise in clinical trials and may represent a new treatment option for people with some types of lipodystrophy.

The adipocyte-myocyte axis in insulin resistance

Insulin resistance in skeletal muscle is linked to an elevated adipose tissue mass, as is found in obesity, but can also be observed in lipodystrophy, in which adipose tissue is greatly reduced. Adipose tissue releases endocrine and metabolic mediators and is actively involved in crosstalk with skeletal muscle, a process that precedes and underlies the development of insulin resistance in muscles. Adipokines including tumor necrosis factor alpha, interleukin-6, leptin and adiponectin influence insulin signaling in skeletal muscle. Free fatty acids, their metabolites and ectopic fat in muscle also contribute to insulin resistance. Recent research indicates inflammation, endoplasmic reticulum stress and oxidative stress could be underlying mechanisms at the center of the development of insulin resistance. Insights into the role of macrophages in adipose tissue add to the complicated interplay between adipose tissue and skeletal muscle.

Fat distribution in women with HIV infection

OBJECTIVE

Both peripheral fat loss and central fat gain have been reported in women with HIV infection. We determined the fat changes that are specific to HIV infection in women.

METHODS

HIV-infected and control women from the study of Fat Redistribution and Metabolic Change in HIV Infection (FRAM) were compared. Lipoatrophy or lipohypertrophy was defined as concordance between participant report of fat change and clinical examination. Whole-body magnetic resonance imaging measured regional adipose tissue volumes. The relationship among different adipose tissue depots was assessed. Factors associated with individual depots were analyzed using multivariate linear regression.

RESULTS

HIV-infected women reported more fat loss than controls in all peripheral and most central depots. Peripheral lipoatrophy was more frequent in HIV-infected women than controls (28% vs. 4%, P < 0.001), whereas central lipohypertrophy was similar (62% vs. 63%). Among HIV-infected women, those with central lipohypertrophy were less likely to have peripheral lipoatrophy (odds ratio, 0.39; 95% confidence interval, 0.20 to 0.75, P = 0.006) than those without central lipohypertrophy. On magnetic resonance imaging, HIV-infected women with clinical peripheral lipoatrophy had less subcutaneous adipose tissue (SAT) in peripheral and central sites and less visceral adipose tissue (VAT) than HIV-infected women without peripheral lipoatrophy. Compared with controls, HIV-infected women had less SAT in the legs, regardless of the presence or absence of lipoatrophy. However, those without lipoatrophy had more VAT and upper trunk SAT than controls. Use of the antiretroviral drug stavudine was associated with less leg SAT but was not associated with VAT. The use of highly active antiretroviral therapy, however, was associated with more VAT.

CONCLUSIONS

Peripheral lipoatrophy occurs commonly in HIV-infected women but is not associated with reciprocally increased VAT or trunk fat.