Seipin Deficiency as a Model of Severe Adipocyte Dysfunction: Lessons from Rodent Models and Teaching for Human Disease.

Obesity prevalence is increasing worldwide, leading to cardiometabolic morbidities. Adipocyte dysfunction, impairing white adipose tissue (WAT) expandability and metabolic flexibility, is central in the development of obesity-related metabolic complications. Rare syndromes of lipodystrophy characterized by an extreme paucity of functional adipose tissue should be considered as primary adipocyte dysfunction diseases. Berardinelli-Seip congenital lipodystrophy (BSCL) is the most severe form with a near absence of WAT associated with cardiometabolic complications such as insulin resistance, liver steatosis, dyslipidemia, and cardiomyopathy. Twenty years ago, mutations in the BSCL2 gene have been identified as the cause of BSCL in human. BSCL2 encodes seipin, an endoplasmic reticulum (ER) anchored protein whose function was unknown back then. Studies of seipin knockout mice or rats demonstrated how seipin deficiency leads to severe lipodystrophy and to cardiometabolic complications. At the cellular levels, seipin is organized in multimers that are particularly enriched at ER/lipid droplet and ER/mitochondria contact sites. Seipin deficiency impairs both adipocyte differentiation and mature adipocyte maintenance. Experiments using adipose tissue transplantation in seipin knockout mice and tissue-specific deletion of seipin have provided a large body of evidence that liver steatosis, cardiomyopathy, and renal injury, classical diabetic complications, are all consequences of lipodystrophy. Rare adipocyte dysfunctions such as in BSCL are the key paradigm to unravel the pathways that control adipocyte homeostasis. The knowledge gathered through the study of these pathologies may bring new strategies to maintain and improve adipose tissue expandability.

Metreleptin worked in a diabetic woman with a history of hematopoietic stem cell transplantation (HSCT) during infancy: further support for the concept of 'HSCT-associated lipodystrophy'.

A 17-year-old woman with a history of childhood leukemia and hematopoietic stem cell transplantation (HSCT), preceded by total body irradiation, developed diabetes, dyslipidemia, fatty liver, and marked insulin resistance. Based on Dunnigan phenotype, HSCT-associated lipodystrophy was suspected. Because of rapid deterioration of diabetes control, metreleptin was introduced at 23 years of age upon receipt of her caregiver's documented consent. This trial was initially planned as a prospective 18 month-long study, with regular assessments of the patient's physical activity, food intake, and body composition analysis. However, because an abrupt and transient attenuation of the metreleptin effect occurred 16 months after the treatment initiation, the entire course of 28 months is reported here. Over the period, her HbA1c decreased from 10.9% to 6.7% despite no significant increase of physical activity and with a stable food intake. Decreased levels of triglyceride and non-HDL cholesterol were found. Her liver function improved, indicating the amelioration of fatty liver. In addition, a 25% reduction in the subcutaneous fat area at umbilical level was found, accompanied by a decrease in fat percentage of both total-body and trunk. The formation of neutralizing antibodies to metreleptin may be responsible for the transient loss of efficacy, considering a sudden elevation in her serum leptin level. In conclusion, metreleptin is useful for the management of HSCT-associated lipodystrophy, supporting the concept that adipose tissue dysfunction is responsible for diverse post-HSCT metabolic aberrations.

The Interplay between Angiopoietin-Like Proteins and Adipose Tissue: Another Piece of the Relationship between Adiposopathy and Cardiometabolic Diseases?

Angiopoietin-like proteins, namely ANGPTL3-4-8, are known as regulators of lipid metabolism. However, recent evidence points towards their involvement in the regulation of adipose tissue function. Alteration of adipose tissue functions (also called adiposopathy) is considered the main inducer of metabolic syndrome (MS) and its related complications. In this review, we intended to analyze available evidence derived from experimental and human investigations highlighting the contribution of ANGPTLs in the regulation of adipocyte metabolism, as well as their potential role in common cardiometabolic alterations associated with adiposopathy. We finally propose a model of ANGPTLs-based adipose tissue dysfunction, possibly linking abnormalities in the angiopoietins to the induction of adiposopathy and its related disorders.

Lipoatrophy in children, adolescents and adults with insulin pump treatment: Is there a beneficial effect of insulin glulisine?

AIM: To investigate whether zinc-free insulin is an effective treatment option for lipoatrophy. METHODS: Controlled, randomized, open-label parallel study in young people with type 1 diabetes, pump treatment and lipoatrophy at injection sites. Participants underwent dermatological examination and evaluation of affected areas using ultrasound and magnetic resonance imaging (MRI). After randomization, half of themswitched to insulin glulisine (intervention group) for 6 months. The control group continued their treatment with zinc-containing insulin and switched to insulin glulisine 6 months later. Both groups were followed-up until month 12. Primary endpoint was the increase of the relative thickness of the subcutaneous fat layer of the most atrophic site at 6 months as documented by MRI. RESULTS: Fourteen participants were included into the study. While relative thickness of subcutaneous fat tissue was comparable between intervention (-60% [-98.8 - -17.6], n = 7) and control group (-50% [-72.7 - -1.0], P = .511; median (range), n = 7)at baseline, it improved in the intervention (-14.3% [-85.7-83.3] vs -31.3% (-66.7-0), P = .031), but not in the control group (P = .125) after 6 months. At 12 months, relative fat thickness (P = .003), number (P = .015) and size of most atrophic sites (P = .001) were improved in the intervention group. Number (P = .018) and size of most atrophic sites (P = .008) were also reduced in the control group between 6 and 12 months. CONCLUSIONS: Although the present pilot study is based on a small sample, the data give first hint that the use of the zinc-free insulin glulisine may be beneficial in people with diabetes, pump and lipoatrophy.

[Recognize rare diseases by the adipose tissue : Lipodystrophy-actually simple but nevertheless often overlooked]. / Seltene Erkrankungen am Fettgewebe erkennen : Lipodystrophie ­ eigentlich einfach und dennoch oft übersehen.

Lipodystrophy (LD) syndromes are a group of rare and heterogeneous diseases characterized by a congenital deficiency or acquired loss of adipose tissue. Due to the resulting disorder of metabolism, sometimes severe sequelae can develop, such as hypertriglyceridemia, marked insulin resistance and early manifestation of type 2 diabetes, recurrent pancreatitis, fatty liver disease and liver fibrosis. Lipodystrophies are clinically recognizable due to the complete lack of subcutaneous adipose tissue or a conspicuous pattern of the distribution of body fat. Acanthosis nigricans in slimly built persons, a high fasting triglyceride level and elevated concentrations of liver enzymes as well as a positive history of pancreatitis can be indications of LD.

Recurrent fevers, progressive lipodystrophy, and annular plaques in a child.

KEY TEACHING POINTS.

Abnormal lipid storage related to adipocyte shrinkage in acquired partial lipodystrophy (Barraquer-Simons syndrome).

BACKGROUND: Acquired partial lipodystrophy (APL) is characterized by the gradual symmetrical loss of subcutaneous fat starting from the face, spreading towards the upper part of the body and sparing the lower extremities. OBJECTIVE: We report a 33-year-old woman with facial lipodystrophy, loss of buccal fat pads and breast fat tissue. The subcutaneous fat was preserved in other anatomic regions, and we noted some excess of fat accumulation in the lower abdomen and thighs. She had a low serum level of C3 that was positive for a polyclonal immunoglobulin C3NeF in the serum. She was diagnosed with APL. METHODS: We examined fat from lipoatrophic and healthy areas and compared it to subcutaneous fat samples from a healthy control. RESULTS: Using scanning electron microscopy, we saw shrunken adipocytes with numerous small lipid droplets detaching from the surface of the adipocytes as compared to the classic aspect of adipose tissue in the control subject where the cytoplasm is occupied by one big lipid droplet. A loss of contact between adipocytes was observed in the APL patient when compared to the normal network of adipocytes in the control subject. The healthy fat seemed not affected by lipoatrophy; we observed normal-sized adipocytes, though their surface was not as regular as in the control samples. CONCLUSION: The significance and mechanism of the electron microscopic findings are unknown, but they suggest adipocyte shrinkage related to a defect in the retaining triglycerides, which could contribute to the pathogenesis of this disorder.

Linear lipoatrophy following intra-articular triamcinolone acetonide injection mimicking linear scleroderma.

A 12-year-old female with oligoarticular juvenile inflammatory arthritis developed an atrophic linear plaque involving the left medial forearm and proximal arm 7 months after intra-articular triamcinolone injection for arthritis. The plaque spontaneously resolved without treatment over approximately one year. It is important to recognize this rare complication of intra-articular steroid injection in order to avoid potential misdiagnosis as linear scleroderma and subsequent immunosuppressive treatment.

Insulin resistance and diabetes caused by genetic or diet-induced KBTBD2 deficiency in mice.

We describe a metabolic disorder characterized by lipodystrophy, hepatic steatosis, insulin resistance, severe diabetes, and growth retardation observed in mice carrying N-ethyl-N-nitrosourea (ENU)-induced mutations. The disorder was ascribed to a mutation of kelch repeat and BTB (POZ) domain containing 2 (Kbtbd2) and was mimicked by a CRISPR/Cas9-targeted null allele of the same gene. Kbtbd2 encodes a BTB-Kelch family substrate recognition subunit of the Cullin-3-based E3 ubiquitin ligase. KBTBD2 targeted p85α, the regulatory subunit of the phosphoinositol-3-kinase (PI3K) heterodimer, causing p85α ubiquitination and proteasome-mediated degradation. In the absence of KBTBD2, p85α accumulated to 30-fold greater levels than in wild-type adipocytes, and excessive p110-free p85α blocked the binding of p85α-p110 heterodimers to IRS1, interrupting the insulin signal. Both transplantation of wild-type adipose tissue and homozygous germ line inactivation of the p85α-encoding gene Pik3r1 rescued diabetes and hepatic steatosis phenotypes of Kbtbd2-/- mice. Kbtbd2 was down-regulated in diet-induced obese insulin-resistant mice in a leptin-dependent manner. KBTBD2 is an essential regulator of the insulin-signaling pathway, modulating insulin sensitivity by limiting p85α abundance.

Diabetes mellitus in HIV-infected patients: fasting glucose, A1c, or oral glucose tolerance test - which method to choose for the diagnosis?

BACKGROUND: Antiretroviral therapy dramatically reduced HIV-related morbidity and mortality, prolonging the lifespan of HIV-infected patients. Greater duration of infection and exposure to antiretroviral therapy makes these patients susceptible to traditional cardio-metabolic risk factors and pathologies. The optimal diagnostic protocol for Diabetes Mellitus in these patients is still controversial. Haemoglobin A1c (HbA1c) has been shown to underestimate glycaemia levels and the oral glucose tolerance test (OGTT) has been shown to reveal cases of glucose metabolism disturbances in patients with normal fasting glucose. Thus, this study aimed to determine the prevalence of prediabetes and diabetes in a population of HIV-infected patients undergoing combined antiretroviral therapy, using three different diagnostic methods (fasting glucose, OGTT and HbA1c), to determine the agreement between the different methods and the characteristics associated with each one. METHODS: This study analyzed 220 HIV-infected patients on antiretroviral therapy. Patient characteristics were collected using a standardized protocol. Disturbances of glucose homeostasis were defined by the ADA 2017 criteria. Patients were characterized according to the presence or absence of clinical lipodystrophy, and distributed into four different categories, according to the presence, or absence of either clinical lipoatrophy, or abdominal prominence. Insulin resistance was assessed by HOMA-IR and QUICKI indexes. Agreement between the diagnostic methods was assessed by Cohen's kappa coefficient. RESULTS: There were no patients diagnosed with diabetes with HbA1c. 5.9% prevalence was obtained when OGTT was used, and 3.2% prevalence when fasting glucose was used. Prediabetes had a prevalence of 14.1% when using HbA1c, 24.1% when using OGTT, and 20% when using fasting glucose. In all three methods, glucose homeostasis disturbances were associated with older age and higher resistance to insulin. Regarding other characteristics, associations varied between the three methods. The agreement between them was fair, or slight. CONCLUSIONS: We observed that HbA1c was the method that diagnosed the least amount of cases and that OGTT was the one that diagnosed the most cases. Accordingly, our results indicate that HbA1c underestimated glycaemia levels in this population and that the use of OGTT might allow an earlier diagnosis of glucose homeostasis disturbances, potentially making it possible to avoid severe complications of DM.

Visceral adipose tissue and carotid intima-media thickness in HIV-infected patients undergoing cART: a prospective cohort study.

BACKGROUND: Combined antiretroviral therapy (cART) in HIV-infected patients has been associated with lipodystrophy, metabolic abnormalities, and an increased risk of cardiovascular disease. Ultrasound measures of carotid artery intima-media thickness (cIMT) have been used as a valid measure of subclinical atherosclerosis and as a tool to predict the risk of cardiovascular events. Our aim was to evaluate the progression of cIMT in HIV-infected patients subjected to cART, with and without lipodystrophy, over a one-year period. METHODS: We performed a one-year prospective cohort study to compare changes in cIMT, metabolic and inflammation markers in HIV-infected patients undergoing cART. Body composition was assessed by dual-energy X-ray absorptiometry (DXA) and abdominal computed tomography (CT). Levels of blood pressure, lipids and inflammatory markers were evaluated, as well as ultrasound measures of cIMT. Lipodystrophy defined by Fat Mass Ratio (L-FMR) is measured as the ratio of the percentage of trunk fat mass to the percentage of lower limb fat mass by DXA. Categorical variables were compared, using the chi-square or Fisher's exact test. Wilcoxon ranks tests and the McNemar chi-square tests were used to compare results of selected variables, from the first to the second year of evaluation. Means of cIMT, adjusted for age, glucose, triglycerides levels, systolic blood pressure (SBP), and waist to hip ratio were calculated, using generalised linear models for repeated measures. RESULTS: L-FMR was present in 44.3% of patients, and the mean of cIMT increased significantly in this group [0.82 (0.26) vs 0.92 (0.33); p = 0.037], as well as in patients without lipodystrophy [0.73 (0.20) vs 0.84 (0.30); p = 0.012]. In the overall sample, the progression of cIMT was statistically significant after the adjustment for age, glucose, triglycerides, and SBP, but the significance of the progression ceased after the adjustment for waist/hip ratio [0.770 (0.737-0.803) vs 0.874 (0.815-0.933); p = 0.514]. CONCLUSIONS: Carotid IMT progressed significantly in both groups of this HIV-infected cohort, however no association between the progression of cIMT and the presence of lipodystrophy defined by FMR was found. Visceral adipose tissue had an impact on the increment of cIMT, both in patients with, and without lipodystrophy defined by FMR.

Temporary resolution of insulin requirement in acquired partial lipodystrophy associated with chronic graft-versus-host disease.

This is a case presentation describing a high insulin requirement that suddenly resolved in a patient with acute lymphoblastic leukemia treated with stem cell transplantation complicated by chronic graft-versus-host disease. The patient was diagnosed with acquired partial lipodystrophy that did not require alternative therapies such as leptin or insulin-like growth factor 1.

Unusual Presentation of Injection Site Adverse Effect.

Insulin is an integral part of Type 1 diabetes management. Patient education is of utmost importance to ensure proper injection technique for getting appropriate glycaemic control and to avoid injection site adverse effects. Commonest injection site adverse effect is lipodystrophy.1 We present a case where incorrect injection technique led to an unusual presentation of injection site adverse effect, which is resolving after correction of the injection technique.

Type 1 diabetes: Syndromes in resource-challenged settings.

Type 1 Diabetes is a complex disorder that is made more complex by the myriad of co-morbid conditions associated with it. Mauriac Syndrome is a well-known but nowadays uncommon condition that presents with growth retardation secondary to poor glycaemic control. Limited Joint Mobility is an often-missed association of diabetes. Its importance lies in the fact that it can cause significant impairment of fine movements in T1DM children. It also indicates poor glycaemic control over a long period of time and can be used as a surrogate marker for development of diabetic microvascular complications. Anaemia in T1DM is protean and can develop due to a combination of nutritional factors, chronic renal disease, coeliac disease and worm infestation. Management is etiological. Vitamin deficiencies are ubiquitous in T1DM and if left untreated, can lead to neurological, haematological and skeletal dysfunction. The best-known co-morbid conditions are the local site reactions clubbed together under the moniker lipodystrophies. These can be either atrophic or hypertrophic and are usually due to repeated injections at the same site, improper technique and needle re-use. Management is often difficult and they are best prevented by appropriate diabetes education and emphasis on proper injection techniques at the time of T1DM diagnosis, with periodic reinforcement. Amyloidosis is a little known condition that shares a lot of features in common with the lipodystrophies and often needs to be differentiated from lipohypertrophy. T1DM is a disease which is often associated with a poor quality of life and these co-morbid conditions also need to be treated for effective general and psychological well-being.

Maraviroc plus raltegravir failed to maintain virological suppression in HIV-infected patients with lipohypertrophy: results from the ROCnRAL ANRS 157 study.

BACKGROUND: Novel nucleoside reverse transcriptase inhibitor- and protease inhibitor-sparing strategies are needed in long-term-treated patients with lipohypertrophy. Given their potency and their excellent metabolic profile, maraviroc and raltegravir appear to be good candidates for such an approach. METHODS: This single-arm study enrolled lipohypertrophic HIV-infected patients with suppressed viraemia and an R5 tropic virus in HIV DNA; they switched from suppressive antiretroviral treatment to maraviroc plus raltegravir. The primary endpoint was the proportion of patients with treatment success at week 24, defined as no virological failure or treatment discontinuation. To ensure a success rate of at least 80%, a maximum of 10 failures were allowed for 90 patients enrolled. ClinicalTrials.gov: NCT01420523. RESULTS: A total of 44 patients were enrolled; their median age was 55 years, median nadir CD4 cell count was 210 cells/mm(3), median time on antiretroviral treatment was 15 years and median duration of viral suppression was 5.2 years. Seven patients failed maraviroc/raltegravir therapy: five had virological failure and two discontinued treatment due to serious adverse events (one had hepatitis B virus reactivation and one had hypersensitivity syndrome). At failure, raltegravir resistance mutations were detected in 3/5 patients and CXCR4 tropic virus in 2/5. Upon DSMB recommendation, the study was prematurely discontinued on 3 September 2012. Lipid profile and bone mineral density improved with a decrease from baseline values in total cholesterol (-0.56 ±â€Š0.95 mmol/L; P = 0.001), low-density lipoprotein cholesterol (-0.31 ±â€Š0.81 mmol/L; P = 0.039) and triglycerides (-0.59 ±â€Š1.12 mmol/L; P = 0.001) and an increase in total hip bone mineral density (+0.9 ±â€Š1.5%; P = 0.013) CONCLUSIONS: In long-term-experienced patients, maraviroc/raltegravir therapy lacks virological robustness despite a benefit in lipid profile and bone density.

Exploring the pathophysiology behind the more common genetic and acquired lipodystrophies.

Lipodystrophies are an immense group of genetic or acquired metabolic disorders that are characterized by varying degrees of body fat loss and in some instances localized accumulation of subcutaneous fat. Lipodystrophies are often tightly linked with profound metabolic complications; this strong bond emphasizes and reinforces the significance of adipose tissue as a dynamic endocrine organ. The extent of fat loss determines the severity of associated metabolic complications such as diabetes mellitus, hypertriglyceridemia and hepatic steatosis. The lipodystrophies can be divided into generalized, partial or local, depending on the degree and locality of the observable fat loss; moreover, the generalized and partial divisions can be partitioned further into inherited or acquired forms. The major genetic factors in the generalized forms of the lipodystrophies, particularly Congenital generalized lipodystrophy (CGL)-Berardinelli-Seip syndrome, are the AGPAT2, BSCL2, caveolin 1 (CAV1) and polymerase-I-and-transcriptrelease factor (PTRF) genes. In the acquired forms, genes such as LMNA, PPARG, CIDEC (cell-death-inducing DNA fragmentation factor a-like effector c) and PLIN1 are heavily involved in familial partial lipodystrophy (FPLD) type 2 (also known as the Dunnigan-Variety) and WRN along with RECQL5 in Werner Syndrome (WS). Autoimmune causes are particularly noted in acquired partial lipodystrophy (APL)-Barraquer-Simons syndrome and in AGL-Lawrence syndrome; panniculitis has been shown to have a substantial role in the former as well as in other forms of localized lipodystrophies. Patients with human immunodeficiency virus (HIV) exposed to protease inhibitors, nucleoside reverse transcriptase inhibitors (NRTIs) (for example, zidovudine and stavudine) or non-nucleoside reverse transcriptase inhibitors (NNRTIs) (for example, efavirenz) while undergoing Highly Active Antiretroviral Therapy (HAART) have led to the current most-prevalent form of the lipodystrophies: lipodystrophy in HIV-infected patients (LD-HIV) and HAART-associated lipodystrophy syndrome (HALS).

Lower extremity lipedema, upper extremity lipodystrophy and severe calcinosis complicating juvenile dermatomyositis.

Juvenile dermatomyositis (JDM) is a rare but complex and potentially life-threatening autoimmune disease of childhood. Significant proportions of patients have residual weakness, muscle atrophy, joint contractures, and calcinosis. Recently, new clinical findings, such as lipodystrophy accompanied with increased fat deposition in certain areas, have been reported. So far, it is not known whether the redistribution of body fat may be the type of lipedema of lower extremity. We describe a 39-year-old woman who was diagnosed with JDM at the age of 7. Later she developed symmetrical lipodystrophy of upper extremities and symmetrical lipedema of lower extremities (making 2 and 58.3 % of total body fat mass, respectively), with multiple calcified nodules in the subcutaneous tissues. These nodules gradually increased in size despite therapy. Capillaroscopy findings showed scleroderma-like abnormalities. ANA and anti-U1RNP antibodies were positive. Similar cases with simultaneous occurrence of the lipedema of lower extremities, lipodystrophy of upper extremities, and severe calcinosis complicating JDM have not been published so far. We showed that the calcinosis and lipodystrophy were associated with short duration of active disease. Also, we display case that raises the question whether it is possible overlapping autoimmune diseases revealed during follow-up.

Partial lipodystrophy: Clinical presentation and treatment.

Lipodystrophic syndromes are acquired or genetic rare diseases, characterized by a generalized or partial lack of adipose tissue leading to metabolic alterations linked to strong insulin resistance. They are probably underdiagnosed, especially for partial forms. They are characterized by a lack of adipose tissue or a lack of adipose development leading to metabolic disorders associated with often severe insulin resistance, hypertriglyceridemia and hepatic steatosis. In partial forms of lipodystrophy, these mechanisms are aggravated by excess visceral adipose tissue and/or subcutaneous adipose tissue in the upper part of the body. Diagnosis is based on clinical examination, pathological context and comorbidities, and on results of metabolic investigations and genetic analyses, which together determine management and genetic counseling. Early lifestyle and dietary measures focusing on regular physical activity, and balanced diet avoiding excess energy intake are crucial. They are accompanied by multidisciplinary follow-up adapted to each clinical form. When standard treatments have failed to control metabolic disorders, the orphan drug metreleptin, an analog of leptin, can be effective in certain forms of lipodystrophy syndromes.

PSMB8 encoding the ß5i proteasome subunit is mutated in joint contractures, muscle atrophy, microcytic anemia, and panniculitis-induced lipodystrophy syndrome.

We performed homozygosity mapping in two recently reported pedigrees from Portugal and Mexico with an autosomal-recessive autoinflammatory syndrome characterized by joint contractures, muscle atrophy, microcytic anemia, and panniculitis-induced lipodystrophy (JMP). This revealed only one homozygous region spanning 2.4 Mb (5818 SNPs) on chromosome 6p21 shared by all three affected individuals from both families. We directly sequenced genes involved in immune response located in this critical region, excluding the HLA complex genes. We found a homozygous missense mutation c.224C>T (p.Thr75Met) in the proteasome subunit, beta-type, 8 (PSMB8) gene in affected patients from both pedigrees. The mutation segregated in an autosomal-recessive fashion and was not detected in 275 unrelated ethnically matched healthy subjects. PSMB8 encodes a catalytic subunit of the 20S immunoproteasomes called ß5i. Immunoproteasome-mediated proteolysis generates immunogenic epitopes presented by major histocompatibility complex (MHC) class I molecules. Threonine at position 75 is highly conserved and its substitution with methionine disrupts the tertiary structure of PSMB8. As compared to normal lymphoblasts, those from an affected patient showed significantly reduced chymotrypsin-like proteolytic activity mediated by immunoproteasomes. We conclude that mutations in PSMB8 cause JMP syndrome, most probably by affecting MHC class I antigen processing.