Lipodystrophic Diabetes Research Articles

The Rare and Atypical Diabetes Network (RADIANT) Study: Design and Early Results.

The Rare and Atypical Diabetes Network (RADIANT) will perform a study of individuals and, if deemed informative, a study of their family members with uncharacterized forms of diabetes. The protocol includes genomic (whole-genome [WGS], RNA, and mitochondrial sequencing), phenotypic (vital signs, biometric measurements, questionnaires, and photography), metabolomics, and metabolic assessments. Among 122 with WGS results of 878 enrolled individuals, a likely pathogenic variant in a known diabetes monogenic gene was found in 3 (2.5%), and six new monogenic variants have been identified in the SMAD5, PTPMT1, INS, NFKB1, IGF1R, and PAX6 genes. Frequent phenotypic clusters are lean type 2 diabetes, autoantibody-negative and insulin-deficient diabetes, lipodystrophic diabetes, and new forms of possible monogenic or oligogenic diabetes. The analyses will lead to improved means of atypical diabetes identification. Genetic sequencing can identify new variants, and metabolomics and transcriptomics analysis can identify novel mechanisms and biomarkers for atypical disease.

Pathogenic genes and adipogenic differentiation transcription factor PPARγ associated with congenital lipodystrophic diabetes

Congenital lipodystrophic diabetes (CLD) is a rare genetic disease characterized by generalized or topical subcutaneous fat loss combined with various metabolic disorders such as insulin resistance, dyslipidemia, and impaired glucose tolerance. Recent studies have discovered genes underlying the disease. Mutations of such genes are associated with adipogenic anomaly, especially regulational function of peroxisome proliferators-activated receptor γ (γPPAR) for lipid. This paper has provided a review for the main clinical symptoms, classification, pathogenic genes, molecular mechanism and the relationship between PPARγ and fat loss.

Abstract #719: Lipodystrophic Diabetes - A Report of Two Cases and Insight into Management

Abstract #719: Lipodystrophic Diabetes - A Report of Two Cases and Insight into Management

Lipodystrophic diabetes mellitus: a lesson for other forms of diabetes?

Lipodystrophies are a genetically heterogeneous group of disorders characterized by loss of subcutaneous adipose tissue and metabolic dysfunction, including insulin resistance, increased levels of free fatty acids, abnormal adipocytokine secretion, and ectopic fat deposition, which are also observed in patients with visceral obesity and/or type 2 diabetes mellitus. Pathophysiological, biochemical, and genetic studies suggest that impairment in multiple adipose tissue functions, including adipocyte maturation, lipid storage, formation and/or maintenance of the lipid droplet, membrane composition, DNA repair efficiency, and insulin signaling, results in severe metabolic and endocrine consequences, ultimately leading to specific lipodystrophic phenotypes. In this review, recent evidences on the causes and metabolic processes of lipodystrophies will be presented, proposing a disease model that could be potentially informative for better understanding of common metabolic diseases in humans, including obesity, metabolic syndrome, and type 2 diabetes.

A soluble activin receptor type IIB does not improve blood glucose in streptozotocin-treated mice.

Type 1 diabetes mellitus (T1DM), or insulin dependent DM, is accompanied by decreased muscle mass. The growth factor myostatin (MSTN) is a negative regulator of muscle growth, and a loss of MSTN signaling has been shown to increase muscle mass and prevent the development of obesity, insulin resistance and lipodystrophic diabetes in mice. The effects of MSTN inhibition in a T1DM model on muscle mass and blood glucose are unknown. We asked whether MSTN inhibition would increase muscle mass and decrease hyperglycemia in mice treated with streptozotocin (STZ) to destroy pancreatic beta cells. After diabetes developed, mice were treated with a soluble MSTN/activin receptor fused to Fc (ACVR2B:Fc). ACVR2B:Fc increased body weight and muscle mass compared to vehicle treated mice. Unexpectedly, ACVR2B:Fc reproducibly exacerbated hyperglycemia within approximately one week of administration. ACVR2B:Fc treatment also elevated serum levels of the glucocorticoid corticosterone. These results suggest that although MSTN/activin inhibitors increased muscle mass, they may be counterproductive in improving health in patients with T1DM.

Caveolin-1 expression and cavin stability regulate caveolae dynamics in adipocyte lipid store fluctuation.

Adipocytes specialized in the storage of energy as fat are among the most caveolae-enriched cell types. Loss of caveolae produces lipodystrophic diabetes in humans, which cannot be reversed by endothelial rescue of caveolin expression in mice, indicating major importance of adipocyte caveolae. However, how caveolae participate in fat cell functions is poorly understood. We investigated dynamic conditions of lipid store fluctuations and demonstrate reciprocal regulation of caveolae density and fat cell lipid droplet storage. We identified caveolin-1 expression as a crucial step in adipose cell lines and in mice to raise the density of caveolae, to increase adipocyte ability to accommodate larger lipid droplets, and to promote cell expansion by increased glucose utilization. In human subjects enrolled in a trial of 8 weeks of overfeeding to promote fattening, adipocyte expansion response correlated with initial caveolin-1 expression. Conversely, lipid mobilization in cultured adipocytes to induce lipid droplet shrinkage led to biphasic response of cavin-1 with ultimate loss of expression of cavin-1 and -3 and EHD2 by protein degradation, coincident with caveolae disassembly. We have identified the key steps in cavin/caveolin interplay regulating adipocyte caveolae dynamics. Our data establish that caveolae participate in a unique cell response connected to lipid store fluctuation, suggesting lipid-induced mechanotension in adipocytes.

A complicated pregnancy in a patient with lipodystrophic diabetes attributable to a peroxisome proliferator‐activated receptor gamma (PPARG) mutation

We describe an unplanned pregnancy in a 19-year-old with lipodystrophic diabetes caused by a mutation in the peroxisome proliferator-activated receptor gamma (PPARG) gene. The pregnancy was complicated by poor compliance with treatment, severe hypertriglyceridaemia and pancreatitis. The patient presented at 6 weeks' gestation with an HbA(1c) of 140 mmol/mol (15%), cholesterol 8.1 mmol/l and triglycerides 20.1 mmol/l. She wished to continue the pregnancy so lipid-lowering therapy was discontinued. She was severely insulin resistant and poorly compliant with diet and medication. A continuous subcutaneous insulin infusion was required for efficient delivery of large doses of basal insulin, alongside injected mealtime boluses, (up to 300 units insulin per day). At 17 weeks' gestation she developed acute pancreatitis secondary to hypertriglyceridaemia (triglycerides > 100 mmol/l) and required plasmapheresis. Lipid-lowering therapy was reinstated in the third trimester and plasmapheresis was required repeatedly to maintain triglycerides < 10 mmol/l. Delivery was arranged at 32 weeks, because of deteriorating glycaemic and lipid control (blood pressure was normal). Following betamethasone for fetal lung maturation, 20 units/h of intravenous insulin were required to maintain glycaemic control. A baby boy with significant subsequent developmental delay was delivered. The features of PPARG mutations are discussed, with literature on lipodystrophy and pancreatitis in pregnancy reviewed. There are few documented cases of pregnancy in women with PPARG mutations. The notable features of this case include the consequences of non-concordance with treatment, the use of continuous subcutaneous insulin infusion to treat insulin-resistant diabetes and the need for repeated plasmapheresis during pregnancy to avert pancreatitis.

Endothelial Function Varies According to Insulin Resistance Disease Type

We examined the relationship between insulin resistance and vascular function in three insulin-resistant states (type 2 diabetes, non-HIV lipodystrophic diabetes, and nondiabetic polycystic ovary syndrome [PCOS]) and in healthy control subjects. The population included 12 women with type 2 diabetes, 6 with lipodystrophic diabetes, 10 with PCOS, and 19 healthy female subjects. Metabolic measures included insulin sensitivity by the homeostasis model assessment, lipids, free fatty acids, and adiponectin. High-resolution B-mode ultrasound was used to determine endothelium-dependent and -independent vasodilation. Type 2 diabetic, liposdystrophic, and PCOS subjects were insulin resistant compared with control subjects (P = 0.001). Flow-mediated vasodilation was reduced in diabetic (3.4 +/- 1.3%) compared with control (7.3 +/- 1.1%) subjects but not in lipodystrophic (7.7 +/- 1.2%) or PCOS (9.9 +/- 0.7%) subjects (P = 0.005). Nitroglycerin-mediated vasodilation was attenuated in both diabetic (15.2 +/- 2.0%) and lipodystrophic (16.7 +/- 3.6%) subjects compared with healthy control (24.6 +/- 2.4%) and PCOS (23.2 +/- 1.8%) subjects (P = 0.019). Insulin resistance, free fatty acids, adiponectin, or C-reactive protein did not associate with vascular dysfunction. Among these different types of patients with insulin resistance, we found abnormal endothelium-dependent vasodilation only in the patients with type 2 diabetes. We postulate that variations in the mechanism of insulin resistance may affect endothelial function differently than glucose homeostasis.

Clinical Experience With U-500 Regular Insulin in Obese, Markedly Insulin-Resistant Type 2 Diabetic Patients

On a clinical basis, severe insulin resistance is defined as a situation in which a patient requires >200 units of insulin daily for >2 days (1). This definition was determined >50 years ago, when it was erroneously believed that the human pancreas secreted ∼200 units of insulin a day. Although it is now known that the normal pancreas secretes only 20–40 units of insulin a day, this clinical definition is helpful because it delineates a very small group of patients, many with a number of unusual underlying problems. In adults, the conditions associated with clinical insulin resistance are gross obesity, severe infection, Cushing’s syndrome, acromegaly, hemochromatosis, lipodystrophic diabetes, genetic insulin receptor abnormalities, insulin receptor antibodies, Werner’s syndrome (adult form of progeria), insulin degradation at the injection site, and high titers of IgG insulin binding antibodies (immune mediated). Gross obesity is by far the most common condition. Although a recent review (2) discussed the use of U-500 regular insulin in states of severe insulin resistance, no detailed description of how to start and adjust doses of this concentrated form of insulin was given. This article provides a treatment algorithm for the use of U-500 regular insulin and summarizes our experience with obese, markedly insulin-resistant type 2 diabetic patients. …

Leptin Improves Insulin Resistance and Hyperglycemia in a Mouse Model of Type 2 Diabetes

Leptin has metabolic effects on peripheral tissues including muscle, liver, and pancreas, and it has been successfully used to treat lipodystrophic diabetes, a leptin-deficient state. To study whether leptin therapy can be used for treatment of more common cases of type 2 diabetes, we used a mouse model of type 2 diabetes (MKR mice) that show normal leptin levels and are diabetic due to a primary defect in both IGF-I and insulin receptors signaling in skeletal muscle. Here we show that leptin administration to the MKR mice resulted in improvement of diabetes, an effect that was independent of the reduced food intake. The main effect of leptin therapy was enhanced hepatic insulin responsiveness possibly through decreasing gluconeogenesis. In addition, the reduction of lipid stores in liver and muscle induced by enhancing fatty acid oxidation and inhibiting lipogenesis led to an improvement of the lipotoxic condition. Our data suggest that leptin could be a potent antidiabetic drug in cases of type 2 diabetes that are not leptin resistant.

Wnt10b Inhibits Development of White and Brown Adipose Tissues

Wnt is a family of secreted signaling proteins that regulate diverse developmental processes. Activation of canonical Wnt signaling by Wnt10b inhibits differentiation of preadipocytes in vitro. To determine whether Wnt signaling blocks adipogenesis in vivo, we created transgenic mice in which Wnt10b is expressed from the FABP4 promoter. Expression of Wnt10b in adipose impairs development of this tissue throughout the body, with a decline of approximately 50% in total body fat and a reduction of approximately 60% in weight of epididymal and perirenal depots. FABP4-Wnt10b mice resist accumulation of adipose tissue when fed a high fat diet. Furthermore, transgenic mice are more glucose-tolerant and insulin-sensitive than wild type mice. Expression of Wnt10b from the FABP4 promoter also blocks development of brown adipose tissue. Interscapular tissue of FABP4-Wnt10b mice has the visual appearance of white adipose tissue but expresses neither brown (e.g. uncoupling protein 1) nor white adipocyte markers. Transgenic mice are unable to maintain a core body temperature when placed in a cold environment, providing further evidence that Wnt10b inhibits development of brown adipose tissue. Although food intake is not altered in FABP4-Wnt10b mice, oxygen consumption is decreased. Thus, FABP4-Wnt10b mice on a chow diet gain more weight than controls, largely because of an increase in weight of skin. In summary, inhibition by Wnt10b of white and brown adipose tissue development results in lean mice without lipodystrophic diabetes.

Transgenic mice lacking white fat: models for understanding human lipoatrophic diabetes.

The human disease lipoatrophic (or lipodystrophic) diabetes is a rare syndrome in which a deficiency of adipose tissue is associated with Type 2 diabetes. This disease is an interesting contrast to the usual situation in which diabetes is associated with obesity, an excess of fat. Aside from obesity, patients with lipodystrophic diabetes have the other features associated with Metabolic Syndrome X, including hypertension and dyslipidemia. The contrast between diabetes with a lack of fat and diabetes with an excess of fat provides an opportunity to study the mechanisms causing Type 2 diabetes and its complications. Recently, three laboratories have produced transgenic mice that are deficient in white adipose tissue. These mice have insulin resistance and other features of lipoatrophic diabetes, and are a faithful model for the human disease. Here we review the different murine models of fat ablation and compare the murine and human diseases, addressing the questions: Is the lack of fat causative of the diabetes, and if so by what mechanism? How could the other clinical features be explained mechanistically? And finally, what can be gleaned about insight into treatment options?

Insulin-Resistant Diabetes Mellitus and Hypermetabolism in Mandibuloacral Dysplasia: A Newly Recognized Form of Partial Lipodystrophy*

Mandibuloacral dysplasia (MAD) is a syndrome characterized by partial lipodystrophy and a distinct phenotype, which includes progressive osteolysis of the mandible and clavicles, cutaneous atrophy, joint contractures, and diabetes mellitus. We now describe the results of hyperinsulinemic glucose clamps performed in conjunction with indirect calorimetry in two subjects with MAD. At a glucose level of 5 mmol/L and insulin concentration of over 6.5 x 10(4) pmol/L, glucose disposal rates were less than 20% of maximum insulin-stimulated glucose disposal in five nondiabetic controls. Basal hepatic glucose output was elevated in the two patients and was incompletely suppressed by a 1200 mU/m2.min infusion of insulin. Glucose and lipid oxidation rates were inappropriately elevated, reflecting marked hypermetabolism. Pharmacological concentrations of insulin failed to normally suppress lipid oxidation, diminish FFA levels, or adequately suppress glucagon levels. In summary, MAD is a unique form of lipodystrophic diabetes characterized by typical somatic features, extreme insulin resistance, and marked hypermetabolism.

Lipodystrophic diabetes mellitus. Investigations of lipoprotein metabolism and the effects of omega-3 fatty acid administration in two patients

We investigated the metabolic effects of omega-6 (safflower oil) and omega-3 (fish oil) fatty acid-enriched diets (65% carbohydrate, 20% fat) in two patients with a syndrome of diabetes mellitus, lipodystrophy, acanthosis nigricans, chylomicronemia, and abdominal pain. 3H-glycerol was used to evaluate triglyceride-rich lipoprotein-triglyceride (TRLP-TG) metabolism, and changes in glucose and insulin dynamics were also studied. On the omega-6 diet, both subjects demonstrated four- to five-times normal rates of TRLP-TG production and glycerol biosynthesis, and striking decrements in the fractional catabolic rate (FCR) for TRLP-TG and TRLP-particles. Both subjects had elevations in nonesterified fatty acid (NEFA) concentrations. In one patient, the omega-3 diet markedly decreased serum triglycerides and newly synthesized triglyceride glycerol production, in association with a fall in NEFA. In both subjects, plasma glycerol reutilization for triglyceride synthesis, normal on the omega-6 diet, was abolished on the omega-3 regimen. Plasma postheparin lipolytic activity was normal on both diets. On the omega-3 diet, xanthomas and hepatomegaly decreased and, in the patient who had no reduction in serum triglycerides, pancreatitis attacks virtually ceased. Mean 24-hour serum glucose levels were higher, and both basal and peak C-peptide responses to a carbohydrate meal were blunted on the omgea-3 diet. One patient became ketonuric. We conclude the cause of hypertriglyceridemia in these patients was due to increased lipid synthesis and hypothesize that this is secondary to high plasma concentrations of NEFA. In addition, an omega-3 diet in these subjects inhibited insulin secretion and worsened glucose tolerance.

Improved acanthosis nigricans with lipodystrophic diabetes during dietary fish oil supplementation

Improved acanthosis nigricans with lipodystrophic diabetes during dietary fish oil supplementation

Improved Acanthosis Nigricans With Lipodystrophic Diabetes During Dietary Fish Oil Supplementation

Acanthosis nigricans is well recognized in its clinical association with several types of insulin-resistant syndromes, and skin involvement is usually unresponsive to local treatment or management of diabetes. A young woman with a lipodystrophic form of diabetes, hypertriglyceridemia, and severe generalized acanthosis nigricans was placed on a diet with fat supplementation in the form of omega-3-fatty-acid-rich fish oil. She was observed to have striking improvement in the appearance and extent of acanthosis nigricans while receiving this regimen. This occurred despite continued therapy with niacin (nicotinic acid), an agent associated with acanthosis nigricanslike skin changes.

Insulin resistance in total lipodystrophy: Evidence for a pre-receptor defect in insulin action

The cause of insulin resistance in lipodystrophic diabetes is unknown but has generally been ascribed to dysfunction at either the receptor or post receptor level. In a 14 year-old girl with total acquired lipodystrophy, subcutaneous and intravenous insulin requirements approximated 600 units daily. However, circulating total and free insulin levels were not increased, and during testing by the euglycemic clamp method, the glucose response to increasing free insulin concentrations was within the range found in eight subjects with insulin-dependent diabetes. Insulin clearance during the euglycemic clamp was 43, 98, 115, and 116 mL/kg/min at each of four insulin infusion rates compared to means of 13, 13, 12, and 11 in the control subjects with diabetes. No detectable degrading activity was present in serum, and serum inhibited insulin degradation normally. Binding of insulin to IgG, IgM, and IgE was not increased, insulin binding to monocytes and erythrocytes was not sufficiently abnormal to account for the insulin resistance, and insulin receptor blocking substances were not present. Therefore, in this patient, the etiology of insulin resistance appears to be related to increased insulin clearance or accelerated degradation of insulin by tissues.

Congenital Lipodystrophic Diabetes With Acanthosis Nigricans

Three living patients with congenital lipodystrophic diabetes and an autopsied infant with leprechaunism have been discussed. Acanthosis nigricans, hirsutism, and generalized lipodystrophy are dermatological features of this multisystem disorder. Other features include increased growth before puberty, enlarged genitalia, diabetes without severe ketosis, hepatomegaly and occasional splenomegaly, enlarged ventricles of the brain, sometimes mental deficiency, large hands and feet, and occasionally congenital anomalies of the heart, bones, and kidneys. The condition is probably transmitted as an autosomal recessive trait.