Lipodystrophy Syndromes

Anti-perilipin-1 autoantibodies in autoimmune Addison's disease and related endocrine disorders

Immune-mediated lipodystrophy syndromes are rare autoimmune disorders characterized by complete or partial destruction of adipocytes in the body. Recently, autoantibodies against perilipin-1 (PLIN1-autoAbs) have been linked to lipodystrophy. Since various perilipins are expressed in the adrenal cortex and ovaries, we asked whether PLIN1-autoAbs were present in patients with adrenal dysfunction and other autoimmune endocrinopathies. Using a sensitive radiobinding immune assay we analyzed anti-PLIN1-autoAbs in 521 patients with endocrinopathies including Sjögren's syndrome. We identified 22 (4.2%) PLIN1-autoAbs positive patients, of whom 15% had autoimmune polyendocrine syndrome type 1 (4/27), 4% autoimmune Addison's disease and/or autoimmune polyendocrine syndrome type 2 (11/274), 8% type 1 diabetes patients (4/53), and 2% Sjögren's syndrome patients (1/50). However, none of them had known lipodystrophy. In conclusion, PLIN1-autoAbs are found in subgroups of autoimmune endocrinopathies and indicate autoimmunity against adipose tissue, but their pathogenic role if any, remains to be defined. Investigating their role in disease progression and their potential as therapeutic targets could pave the way for novel interventions in autoimmune endocrine diseases.

Global Analysis and Latest Research Hot Spots of Lipoedema/Lipodystrophy Investigation and Management: A Bibliometric Analysis and Visualized Review

BACKGROUND

Lipodystrophy presents clinical management challenges due to its varied expression and low incidence. Despite the clinical importance, there has been no systematic evaluation of the research output in terms of geographical distribution, institutional contributions, or emerging trends. This study aims to fill that gap by conducting a comprehensive bibliometric analysis of the global research landscape on lipodystrophy.

METHODS

Utilizing the Web of Science core collection, studies from 2010 to 2024 were analyzed. Bibliometric indicators were processed using VOSviewer to identify trends through graphical co-occurrence mapping.

RESULTS

A total of 826 studies from 57 countries were included. The USA led with 259 publications (30.51%). The most productive institutions were the National Institute of Diabetes and Digestive and Kidney Diseases with 43 publications (14.98%). Among 166 journals, the Journal of Clinical Endocrinology and Metabolism had the highest publications (43, 25.90%) and citations per publication (58). The most co-cited article was The Diagnosis and Management of Lipodystrophy Syndromes (2016), which was referenced 290 times.

CONCLUSION

This analysis highlights research trends and collaborative networks, areas for future investigation, and identifies the gaps and emerging trends that will inform future research directions.

NO LEVEL ASSIGNED

This journal requires that authors assign a level of evidence to each submission to which Evidence-Based Medicine rankings are applicable. This excludes Review Articles, Book Reviews, and manuscripts that concern Basic Science, Animal Studies, Cadaver Studies, and Experimental Studies. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Leptin acutely increases hepatic triglyceride secretion in patients with lipodystrophy

BACKGROUND AND AIMS

Metreleptin ameliorates hepatic steatosis partially independent of its anorexic action. We previously showed that metreleptin increases hepatic very low-density lipoprotein triglycerides (VLDL1-TG) export in rodents and healthy humans requiring intact hepatic autonomic innervation. The primary aim of this study was to investigate whether metreleptin has anti-steatotic properties in patients with lipodystrophy by increasing VLDL1-TG export. In addition, we present a case of generalized lipodystrophy undergoing metreleptin treatment after liver transplantation, a model for hepatic autonomic denervation.

METHODS

In this randomized, placebo-controlled, crossover trial (EudraCT 2017-003014-22) we assessed the acute effects of a single metreleptin injection in 10 patients (8 females, 2 males; mean age ± SD: 49 ± 14 yrs; 9 familial partial and 1 generalized lipodystrophy) on hepatic VLDL1-TG secretion and hepatocellular lipid content (HCL) measured via an intravenous fat emulsion test and 1H-magnetic resonance spectroscopy, respectively.

RESULTS

We found that a single injection of metreleptin increased hepatic VLDL1-TG secretion by 75 % (mean difference ± SD: +219 ± 149 mg/h metreleptin vs. placebo; p = 0.001), without significant changes in HCL within 3 h (mean difference ± SD: -8 ± 14 % metreleptin vs. placebo, p = 0.14). Metreleptin therapy in a patient with generalized lipodystrophy following liver transplantation failed to ameliorate hepatic steatosis despite improving glucose and lipid metabolism.

CONCLUSIONS

Leptin acutely increases hepatic VLDL1-TG secretion in patients with lipodystrophy, likely contributing to metreleptin's body weight-independent anti-steatotic effects. The case report suggests that intact autonomic liver innervation may be required for this action, warranting further research.

Barraquer Simons Syndrome: Case Series and Review of Surgical Treatments for Facial Lipodystrophy

BACKGROUND

Barraquer Simons Syndrome (BSS) is a subtype of idiopathic acquired lipodystrophy, wherein patients-mostly female-lose subcutaneous fat in the upper half of the body starting in childhood or puberty. A disproportionate fat allocation can be seen in the trochanteric region and thighs.

METHODS

Along with three cases of lipoatrophy treated at our hospital, we conducted a comprehensive review and presented the treatments in the literature for improving bilateral facial lipodystrophy.

RESULTS

Flaps and autologous fat grafting procedures were favored across the literature, and regardless of the intervention of choice, patients reported satisfaction and improved life prospects.

CONCLUSION

The loss of facial fat is especially afflicting for patients as the bilateral lipoatrophy imparts an aged, cachexic look which negatively affects not only their self-image but their social status as well. Alternatives to approach lipoatrophy vary in their invasiveness, permanency, and feasibility; thus, treatments must be thoroughly tailored to each patient's needs and expectations. Barraquer Simons Syndrome is a rare subtype of lipodystrophy primarily affecting females, leading to fat loss in mainly the upper body. The negative social impact of the syndrome necessitates intervention, and patients receiving appropriate treatment reported improved psychosocial parameters. Treatment plans should consider each patient's specific needs and expectations, balancing invasiveness, permanency, and feasibility of the procedures.

LEVEL OF EVIDENCE IV

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors   www.springer.com/00266 .

A case of familial partial lipodystrophy type 2 masquerading as Cushing syndrome: Explaining an atypical phenotype by whole-exome sequencing

Familial partial lipodystrophy type 2 is a rare disease, particularly when it is caused by nonclassical gene variants. A high index of suspicion is essential for a timely diagnosis. We present the case of a 32-year-old woman, referred to evaluation of a possible Cushing syndrome, which was clinically and biochemically ruled out. Yet, due to the finding of a rather abnormal fat distribution during physical examination, the diagnosis of lipodystrophy was cogitated. Whole-exome sequencing revealed a missense variant of exon 11 R582H of the gene encoding Laminin A (rs57830985,c.1745G>A, p.Arg582His). The patient presented some clinical and biochemical characteristics discordant with those previously reported in patients harboring other classical variants of this gene.

Acquired Generalized Lipodystrophy as an Adverse Event of Combined Immune Checkpoint Inhibitor Therapy

Acquired generalized lipodystrophy (AGL) is rarely associated with immune checkpoint inhibitors (ICIs). A few cases report associations with inhibitors to programmed cell death protein 1 (PD-1 inhibitors); however, association with combined immunotherapies has not been reported. We present a 48-year-old female with recurrent malignant melanoma who underwent 23 cycles of nivolumab, a PD-1 inhibitor, and 11 cycles of combined cytotoxic T lymphocyte associated antigen 4 (CTLA-4) inhibitor and PD-1 inhibitor ipilimumab-nivolumab. During the latter course of combination therapy, she experienced progressive weight loss and a dramatic change in body habitus over 3 to 6 months. Physical examination showed generalized loss of subcutaneous fat with protruding veins and muscular definition. Metabolic workup showed new-onset diabetes mellitus, a very low high-density lipoprotein, severe hypertriglyceridemia, and undetectable leptin/adiponectin levels. Whole-body fluorodeoxyglucose positron emission tomography performed for restaging and response assessment revealed generalized soft tissue edema and diffuse hepatic steatosis. An excisional skin biopsy identified changes consistent with involutional lipoatrophy/lipodystrophy. Treatment included insulin (average total daily dose 0.13-0.26 Units/kg/day) and a combination of lipid-lowering therapy (statins, fenofibrate, icosapent ethyl), which led to marked improvement in triglycerides and symptoms. This case further underscores the emerging challenges with endocrinopathies associated with checkpoint inhibitors.

Atrophic Facial Plaque in a 4-Month-Old Male: An Unusual Presentation of Hair Follicle Nevus

Hair follicle nevus is a rare benign follicular hamartoma that is characterized histologically by the proliferation of vellus hair follicles with peri-follicular fibrous thickening. Clinically, hair follicle nevus is most commonly reported as an asymptomatic papule or nodule on the head and neck. Here, we describe an unusual presentation of hair follicle nevus presenting as an atrophic plaque on the cheek of a male infant.

Assessment of aortomesenteric distance and mesenteric and retroperitoneal adipose tissue thickness in genetic forms of lipodystrophy

INTRODUCTION

Lipodystrophy is a rare disease characterized by the loss of adipose tissue. Visceral adipose tissue loss in certain forms of lipodystrophy may affect the amount of mesenteric fat.

METHOD

We studied visceral adipose tissue by measuring the thickness of mesenteric and retroperitoneal adipose tissue and the aortomesenteric (AOM) distance in patients with genetic forms of lipodystrophy (n = 48; 7 males; 41 females; mean age 39.1 ± 11.9 years; 19 with congenital generalized lipodystrophy [CGL], and 29 with familial partial lipodystrophy [FPLD]). An age- and gender-matched control group with a ratio of 1:2 was generated.

RESULTS

Patients with CGL had severely depleted mesenteric adipose tissue (2.0 [IQR: 1.5-3.5] mm vs. 18.8 [IQR: 4.4-42.2] mm in FPLD, P < .001; 30.3 [IQR: 13.9-46.6] mm in controls, P < .001) and retroperitoneal adipose tissue (1.3 [IQR: 0.0-5.3] mm vs. 33.7 [IQR: 21.6-42.1] mm in FPLD, P < .001; 29.7 [IQR: 23.1-36.7] mm in controls, P < .001). The AOM distance was shorter in patients with CGL (8.1 [IQR: 6.0-10.8] mm) compared to patients with FPLD (vs. 13.0 [IQR: 8.8-18.1] mm; P = .023) and controls (vs. 11.3 [IQR: 8.4-15.5] mm, P = .016). Leptin levels were positively correlated with AOM distance in lipodystrophy (r = .513, P < .001). Multivariate linear regression analysis identified body mass index as a significant predictor of AOM distance (data controlled for age and sex; beta = 0.537, 95% CI: 0.277-0.798, P < .001). Twelve of 19 patients (63%) with CGL had an AOM distance of < 10 mm, a risk factor that may predispose patients to developing superior mesenteric artery syndrome.

CONCLUSION

CGL is associated with a severe loss of mesenteric adipose tissue, which leads to a narrowing of the space between the superior mesenteric artery and the aorta.

HIV-TAT dysregulates microglial lipid metabolism through SREBP2/miR-124 axis: Implication of lipid droplet accumulation microglia in NeuroHIV

Chronic HIV infection can dysregulate lipid/cholesterol metabolism in the peripheral system, contributing to the higher incidences of diabetes and atherosclerosis in HIV (+) individuals. Recently, accumulating evidence indicate that HIV proteins can also dysregulate lipid/cholesterol metabolism in the brain and such dysregulation could be linked with the pathogenesis of HIV-associated neurological disorders (HAND)/NeuroHIV. To further characterize the association between lipid/cholesterol metabolism and HAND, we employed HIV-inducible transactivator of transcription (iTAT) and control mice to compare their brain lipid profiles. Our results reveal that HIV-iTAT mice possess dysregulated lipid profiles and have increased numbers of lipid droplets (LDs) accumulation microglia (LDAM) in the brains. HIV protein TAT can upregulate LDs formation through enhancing the lipid/cholesterol synthesis in vitro. Mechanistically, HIV-TAT increases the expression of sterol regulatory element-binding protein 2 (SREBP2) through microRNA-124 downregulation. Cholesterol synthesis inhibition can block HIV-TAT-mediated NLRP3 inflammasome activation and microglial activation in vitro as well as mitigate aging-related behavioral impairment and memory deficiency in HIV-iTAT mice. Taken together, our results indicate an inherent role of lipid metabolism and LDAM in the pathogenesis of NeuroHIV (immunometabolism). These findings suggest that LDAM reversal through modulating lipid/cholesterol metabolism could be a novel therapeutic target for ameliorating NeuroHIV symptoms in chronic HIV (+) individuals.

Adipose Tissue as a Major Launch Spot for Circulating Extracellular Vesicle-Carried MicroRNAs Coordinating Tissue and Systemic Metabolism

Circulating microRNAs (miRNAs), especially transported by extracellular vesicles (EVs), have recently emerged as major new participants in interorgan communication, playing an important role in the metabolic coordination of our tissues. Among these, adipose tissue displays an extraordinary ability to secrete a vast list of EV-carried miRNAs into the circulation, representing new hormone-like factors. Despite the limitations of current methodologies for the unequivocal identification of the origin and destination of EV-carried miRNAs in vivo, recent investigations clearly support the important regulatory role of adipose-derived circulating miRNAs in shaping the metabolism and function of other tissues including the liver, muscle, endocrine pancreas, cardiovascular system, gastrointestinal tract, and brain. Here, we review the most recent findings regarding miRNAs transported by adipose-derived EVs (AdEVs) targeting other major metabolic organs and the implications of this dialog for physiology and pathology. We also review here the current and potential future diagnostic and therapeutic applications of AdEV-carried miRNAs.

Peroxisome proliferator-activated receptor gamma mutation in familial partial lipodystrophy type three: A case report and review of literature

BACKGROUND

Familial partial lipodystrophy disease (FPLD) is a collection of rare genetic diseases featuring partial loss of adipose tissue. However, metabolic difficulties, such as severe insulin resistance, diabetes, hypertriglyceridemia, and hypertension frequently occur alongside adipose tissue loss, making it susceptible to misdiagnosis and delaying effective treatment. Numerous genes are implicated in the occurrence of FPLD, and genetic testing has been for conditions linked to single gene mutation related to FPLD. Reviewing recent reports, treatment of the disease is limited to preventing and improving complications in patients.

CASE SUMMARY

In 2017, a 31-year-old woman with diabetes, hypertension and hypertriglyceridemia was hospitalized. We identified a mutation in her peroxisome proliferator-activated receptor gamma (PPARG) gene, Y151C (p.Tyr151Cys), which results in a nucleotide substitution residue 452 in the DNA-binding domain (DBD) of PPARG. The unaffected family member did not carry this mutation. Pioglitazone, a PPARG agonist, improved the patient's responsiveness to hypoglycemic and antihypertensive therapy. After one year of treatment in our hospital, the fasting blood glucose and glycosylated hemoglobin of the patient were close to normal.

CONCLUSION

We report a rare PPARG mutation, Y151C, which is located in the DBD of PPARG and leads to FPLD, and the preferred agent is PPARG agonists. We then summarized clinical phenotypic characteristics of FPLD3 caused by PPARG gene mutations, and clarified the relationship between different mutations of PPARG gene and the clinical manifestations of this type of FPLD. Additionally, current treatments for FPLD caused by PPARG mutations are reviewed.

Treatment of facial lipodystrophy induced by a biologic agent (IPD-1): a literature review

Agents that inhibit programmed cell death (IPD-1) in T lymphocytes are indicated for patients with advanced cancer. However, some individuals may develop endocrinological conditions, such as diabetes, thyroid dysfunction, and lipodystrophy, after treatment. This systematic review and case report of IPD-1 lipodystrophies describes a patient who received nivolumab treatment for advanced clear cell renal carcinoma and subsequently developed diabetes as well as facial and body lipodystrophy. The patient complained of social distress due to her facial appearance. We treated the facial lipodystrophy with autologous fat grafting, which proved to be effective for more than three years. This study showed the efficacy of IPD-1 lipodystrophy treatment with long-term follow-up.

Plasma membrane remodeling determines adipocyte expansion and mechanical adaptability

Adipocytes expand massively to accommodate excess energy stores and protect the organism from lipotoxicity. Adipose tissue expandability is at the center of disorders such as obesity and lipodystrophy; however, little is known about the relevance of adipocyte biomechanics on the etiology of these conditions. Here, we show in male mice in vivo that the adipocyte plasma membrane undergoes caveolar domain reorganization upon lipid droplet expansion. As the lipid droplet grows, caveolae disassemble to release their membrane reservoir and increase cell surface area, and transfer specific caveolar components to the LD surface. Adipose tissue null for caveolae is stiffer, shows compromised deformability, and is prone to rupture under mechanical compression. Mechanistically, phosphoacceptor Cav1 Tyr14 is required for caveolae disassembly: adipocytes bearing a Tyr14Phe mutation at this residue are stiffer and smaller, leading to decreased adiposity in vivo; exhibit deficient transfer of Cav1 and EHD2 to the LD surface, and show distinct Cav1 molecular dynamics and tension adaptation. These results indicate that Cav1 phosphoregulation modulates caveolar dynamics as a relevant component of the homeostatic mechanoadaptation of the differentiated adipocyte.

Exploring lipodystrophy gene expression in adipocytes: unveiling insights into the pathogenesis of insulin resistance, type 2 diabetes, and clustering diseases (metabolic syndrome) in Asian Indians

Background

Studying the molecular mechanisms of lipodystrophy can provide valuable insights into the pathophysiology of insulin resistance (IR), type 2 diabetes (T2D), and other clustering diseases [metabolic syndrome (MetS)] and its underlying adipocentric disease (MetS disease).

Methods

A high-confidence lipodystrophy gene panel comprising 50 genes was created, and their expressions were measured in the visceral and subcutaneous (both peripheral and abdominal) adipose depots of MetS and non-MetS individuals at a tertiary care medical facility.

Results

Most lipodystrophy genes showed significant downregulation in MetS individuals compared to non-MetS individuals in both subcutaneous and visceral depots. In the abdominal compartment, all the genes showed relatively higher expression in visceral depot as compared to their subcutaneous counterpart, and this difference narrowed with increasing severity of MetS. Their expression level shows an inverse correlation with T2D, MetS, and HOMA-IR and with other T2D-related intermediate traits. Results also demonstrated that individualization of MetS patients could be done based on adipose tissue expression of just 12 genes.

Conclusion

Adipose tissue expression of lipodystrophy genes shows an association with MetS and its intermediate phenotypic traits. Mutations of these genes are known to cause congenital lipodystrophy syndromes, whereas their altered expression in adipose tissue contributes to the pathogenesis of IR, T2D, and MetS.

Transcriptome dataset of mouse adipose tissue across estrous cycles

Adipose tissue is crucial for energy storage and release, ensuring energy homeostasis within the body. Disturbances in the physiology of adipose tissue have been associated with various health disorders, such as obesity and diabetes. The reproductive cycle represents a fundamental biological pattern in female physiology. Although previous research has highlighted the substantial regulatory influence of ovarian hormones on adipose tissue, our understanding of the comprehensive changes in adipose tissue throughout the reproductive cycle remains limited. In this study, we examined the transcriptomic profile of female mouse-adipose tissue across their complete estrous cycles. The findings provided detailed descriptions of the datasets generated, including information on data collection, processing, and quality control. The study also demonstrated the robustness of these data through various validation steps. These findings serve as crucial resources for investigating the role of estrous cycle rhythmicity in important adipose tissue processes in the future.

Circulating exosomal circRNA-miRNA-mRNA network in a familial partial lipodystrophy type 3 family with a novel PPARG frameshift mutation c.418dup

Familial partial lipodystrophy 3 (FPLD3) is a rare genetic disorder caused by loss-of-function mutations in the PPARG gene, characterized by a selective absence of subcutaneous fat and associated metabolic complications. However, the molecular mechanisms of FPLD3 remain unclear. In this study, we recruited a 17-yr-old Chinese female with FPLD3 and her family, identifying a novel PPARG frameshift mutation (exon 4: c.418dup: p.R140Kfs*7) that truncates the PPARγ protein at the seventh amino acid, significantly expanding the genetic landscape of FPLD3. By performing next-generation sequencing of circular RNAs (circRNAs), microRNAs (miRNAs), and mRNAs in plasma exosomes, we discovered 59 circRNAs, 57 miRNAs, and 299 mRNAs were significantly altered in the mutation carriers compared with the healthy controls. Integration analysis highlighted that the circ_0001597-miR-671-5p pair and 18 mRNAs might be incorporated into the metabolic regulatory networks of the FPLD3 induced by the novel PPARG mutation. Functional annotation suggested that these genes were significantly enriched in glucose- and lipid metabolism-related pathways. Among the circRNA-miRNA-mRNA network, we identified two critical regulators, early growth response-1 (EGR1), a key transcription factor known for its role in insulin signaling pathways and lipid metabolism, and 1-acylglycerol-3-phosphate O-acyltransferase 3 (AGPAT3), which gets involved in the biosynthesis of triglycerides and lipolysis. Circ_0001597 regulates the expression of these genes through miR-671-5p, potentially contributing to the pathophysiology of FPLD3. Overall, this study clarified a circulating exosomal circRNA-miRNA-mRNA network in a FPLD3 family with a novel PPARG mutation, providing evidence for exploring promising biomarkers and developing novel therapeutic strategies for this rare genetic disorder.NEW & NOTEWORTHY Through the establishment of a ceRNA regulatory networks in a novel PPARG frameshift mutation c.418dup-induced FPLD3 pedigree, this study reveals that circ_0001597 may contribute to the pathophysiology of FPLD3 by sequestering miR-671-5p to regulate the expression of EGR1 and AGPAT3, pivotal genes situated in the triglyceride (TG) synthesis and lipolysis pathways. Current findings expand our molecular understanding of adipose tissue dysfunction, providing potential blood biomarkers and therapeutic avenues for lipodystrophy and associated metabolic complications.

Case report: First Chinese patient with family partial lipodystrophy type 6 due to novel compound heterozygous mutations in the LIPE gene

Background

Family partial lipodystrophy (FPLD) is a rare autosomal dominant disease characterized by disorders of variable body fat loss associated with metabolic complications. FPLD6 has only been reported in a limited number of cases. Here, we reported a Chinese FPLD6 patient with compound heterozygous mutations in the lipase E, hormone-sensitive type (LIPE) gene.

Case presentation

A 20-year-old female patient presented with hypertriglyceridemia, diabetes mellitus, hepatomegaly, and hepatic steatosis. Subcutaneous fat was significantly diminished in her face, abdomen, and limbs. The patient was assessed by detailed clinical and biochemical examinations. A liver biopsy showed severe lipodystrophy. In addition, there were retinal changes, peripheral nerve damage, and renal tubular injury. Sequencing was performed on extracted DNA. Genetic analysis revealed that the patient had compound heterozygous mutations in the LIPE gene: c.2497_250ldel (p.Glu833LysfsTer22) and c.2705del (p.Ser902ThrfsTer27) heterozygous mutations. Verification revealed that this mutation was inherited from her father and mother, respectively, and that they formed newly discovered compound heterozygous mutations occurring in the LIPE gene, causing FPLD6.

Conclusion

We reported the first case of FPLD6 in China. Gene analysis demonstrated compound heterozygous mutations in LIPE in this patient. Our case emphasizes the importance of genetic testing in young patients with severe metabolic syndromes.

Navigating Lipodystrophy: Insights from Laminopathies and Beyond

Recent research into laminopathic lipodystrophies-rare genetic disorders caused by mutations in the LMNA gene-has greatly expanded our knowledge of their complex pathology and metabolic implications. These disorders, including Hutchinson-Gilford progeria syndrome (HGPS), Mandibuloacral Dysplasia (MAD), and Familial Partial Lipodystrophy (FPLD), serve as crucial models for studying accelerated aging and metabolic dysfunction, enhancing our understanding of the cellular and molecular mechanisms involved. Research on laminopathies has highlighted how LMNA mutations disrupt adipose tissue function and metabolic regulation, leading to altered fat distribution and metabolic pathway dysfunctions. Such insights improve our understanding of the pathophysiological interactions between genetic anomalies and metabolic processes. This review merges current knowledge on the phenotypic classifications of these diseases and their associated metabolic complications, such as insulin resistance, hypertriglyceridemia, hepatic steatosis, and metabolic syndrome, all of which elevate the risk of cardiovascular disease, stroke, and diabetes. Additionally, a range of published therapeutic strategies, including gene editing, antisense oligonucleotides, and novel pharmacological interventions aimed at addressing defective adipocyte differentiation and lipid metabolism, will be explored. These therapies target the core dysfunctional lamin A protein, aiming to mitigate symptoms and provide a foundation for addressing similar metabolic and genetic disorders.

Review article: Hepatic steatosis and its associations with acute and chronic liver diseases

BACKGROUND

Hepatic steatosis is a common finding in liver histopathology and the hallmark of metabolic dysfunction-associated steatotic liver disease (MASLD), formerly known as non-alcoholic fatty liver disease (NAFLD), whose global prevalence is rising.

AIMS

To review the histopathology of hepatic steatosis and its mechanisms of development and to identify common and rare disease associations.

METHODS

We reviewed literature on the basic science of lipid droplet (LD) biology and clinical research on acute and chronic liver diseases associated with hepatic steatosis using the PubMed database.

RESULTS

A variety of genetic and environmental factors contribute to the development of chronic hepatic steatosis or steatotic liver disease, which typically appears macrovesicular. Microvesicular steatosis is associated with acute mitochondrial dysfunction and liver failure. Fat metabolic processes in hepatocytes whose dysregulation leads to the development of steatosis include secretion of lipoprotein particles, uptake of remnant lipoprotein particles or free fatty acids from blood, de novo lipogenesis, oxidation of fatty acids, lipolysis and lipophagy. Hepatic insulin resistance is a key feature of MASLD. Seipin is a polyfunctional protein that facilitates LD biogenesis. Assembly of hepatitis C virus takes place on LD surfaces. LDs make important, functional contact with the endoplasmic reticulum and other organelles.

CONCLUSIONS

Diverse liver pathologies are associated with hepatic steatosis, with MASLD being the most important contributor. The biogenesis and dynamics of LDs in hepatocytes are complex and warrant further investigation. Organellar interfaces permit co-regulation of lipid metabolism to match generation of potentially toxic lipid species with their LD depot storage.

A rapid action plan to improve diagnosis and management of lipodystrophy syndromes

Introduction

Lipodystrophy syndromes are rare diseases that can present with a broad range of symptoms. Delays in diagnosis are common, which in turn, may predispose to the development of severe metabolic complications and end-organ damage. Many patients with lipodystrophy syndromes are only diagnosed after significant metabolic abnormalities arise. Prompt action by clinical teams may improve disease outcomes in lipodystrophy syndromes. The aim of the Rapid Action Plan is to serve as a set of recommendations from experts that can support clinicians with limited experience in lipodystrophy syndromes.

Methods

The Rapid Action Plan was developed using insights gathered through a series of advisory meetings with clinical experts in lipodystrophy syndromes. A skeleton template was used to facilitate interviews. A consensus document was developed, reviewed, and approved by all experts.

Results

Lipodystrophy is a clinical diagnosis. The Rapid Action Plan discusses tools that can help diagnose lipodystrophy syndromes. The roles of clinical and family history, physical exam, patient and family member photos, routine blood tests, leptin levels, skinfold measurements, imaging studies, and genetic testing are explored. Additional topics such as communicating the diagnosis to the patients/families and patient referrals are covered. A set of recommendations regarding screening and monitoring for metabolic diseases and end-organ abnormalities is presented. Finally, the treatment of lipodystrophy syndromes is reviewed.

Discussion

The Rapid Action Plan may assist clinical teams with the prompt diagnosis and holistic work-up and management of patients with lipodystrophy syndromes, which may improve outcomes for patients with this rare disease.

Primary disease of adipose tissue: When to think about and how to evaluate it in clinical practice?

Primary diseases of adipose tissue are rare disorders resulting from impairments in the physiological functions of adipose tissue (lipid stockage and endocrine function). It mainly refers to lipodystrophy syndromes with subcutaneous adipose tissue atrophy and/or altered body distribution of adipose tissue leading to insulin resistance, diabetes, hepatic steatosis, dyslipidemia, cardiovascular complications and polycystic ovary syndrome in women. Those syndromes are congenital or acquired, and lipoatrophy is partial or generalized. The diagnosis of lipodystrophy syndromes is often unrecognized, delayed and/or inaccurate, while it is of major importance to adapt investigations to search for specific comorbidities, in particular cardiovascular involvement, and set up multidisciplinary care, and in some cases specific treatment. Physicians have to recognize the clinical and biological elements allowing to establish the diagnosis. Lipodystrophic syndromes should be considered, notably, in patients with diabetes at a young age, with a normal or low BMI, negative pancreatic autoantibodies, presenting clinical signs of lipodystrophy and insulin resistance (acanthosis nigricans, hyperandrogenism, hepatic steatosis, high insulin doses). The association of diabetes and a family history of severe and/or early cardiovascular disease (coronary atherosclerosis, cardiomyopathy with rhythm and/or conduction disorders) may reveal Dunnigan syndrome, the most frequent form of familial lipodystrophy, due to LMNA pathogenic variants. Clinical assessment is primarily done through clinical examination: acanthosis nigricans, abnormal adipose tissue distribution, lipoatrophy, muscular hypertrophy, acromegaloid or Cushingoid features, lipomas, highly visible subcutaneous veins, may be revealing signs. The amount of circulating adipokines may reflect of adipose dysfunction with low leptinemia and adiponectinemia. Other biological metabolic parameters (hypertriglyceridemia, hyperinsulinemia, increased glycemia and hepatic enzymes) may also represent markers of insulin resistance. Quantification of total body fat by impedancemetry or dual-photon X-ray absorptiometry (DEXA) reveals decreased total body mass, in correlation with adipose tissue atrophy; metabolic magnetic resonance imaging can also quantify intraperitoneal and abdominal fat and the degree of hepatic steatosis. Histological analysis of adipose tissue showing structural abnormalities should be reserved for clinical research. Acquired lipodystrophic syndromes most often lead to similar clinical phenotype as congenital syndromes with generalized or partial lipoatrophy. The most frequent causes are old anti-HIV therapy or glucocorticoid treatments. Family history, history of treatments and clinical examination, including a careful physical examination, are keys for diagnosis.

Rab18 maintains homeostasis of subcutaneous adipose tissue to prevent obesity-induced metabolic disorders

Metabolically healthy obesity refers to obese individuals who do not develop metabolic disorders. These people store fat in subcutaneous adipose tissue (SAT) rather than in visceral adipose tissue (VAT). However, the molecules participating in this specific scenario remain elusive. Rab18, a lipid droplet (LD)-associated protein, mediates the contact between the endoplasmic reticulum (ER) and LDs to facilitate LD growth and maturation. In the present study, we show that the protein level of Rab18 is specifically upregulated in the SAT of obese people and mice. Rab18 adipocyte-specific knockout (Rab18 AKO) mice had a decreased volume ratio of SAT to VAT compared with wildtype mice. When subjected to high-fat diet (HFD), Rab18 AKO mice had increased ER stress and inflammation, reduced adiponectin, and decreased triacylglycerol (TAG) accumulation in SAT. In contrast, TAG accumulation in VAT, brown adipose tissue (BAT) or liver of Rab18 AKO mice had a moderate increase without ER stress stimulation. Rab18 AKO mice developed insulin resistance and systematic inflammation. Rab18 AKO mice maintained body temperature in response to acute and chronic cold induction with a thermogenic SAT, similar to the counterpart mice. Furthermore, Rab18-deficient 3T3-L1 adipocytes were more prone to palmitate-induced ER stress, indicating the involvement of Rab18 in alleviating lipid toxicity. Rab18 AKO mice provide a good animal model to investigate metabolic disorders such as impaired SAT. In conclusion, our studies reveal that Rab18 is a key and specific regulator that maintains the proper functions of SAT by alleviating lipid-induced ER stress.

The role of lipid droplet associated proteins in inherited human disorders

Proteins which associate with the surface of lipid droplets are intimately involved in the regulation of the droplets. Several human inherited disorders have now been linked to loss- and, in some cases, likely gain-of-function mutations in the genes encoding these proteins. These are summarised in this Graphical Review.

A Novel Subtype of Acquired Generalized Lipodystrophy Associated With Subcutaneous Panniculitis-Like T-cell Lymphoma

Acquired generalized lipodystrophy (AGL) is an extremely rare disease that is characterized by loss of body fat affecting nearly all parts of the body. It is often associated with autoimmune diseases or panniculitis, whereas in other patients the underlying etiology is unclear. We report a 52-year-old male individual who was diagnosed with subcutaneous panniculitis-like T-cell lymphoma (SPTCL) that spontaneously went into remission. Years later he developed new subcutaneous nodules most concerning for relapse SPTCL or lupus panniculitis, followed by onset of hemophagocytic lymphohistiocytosis (HLH) that was treated with allogeneic stem cell transplantation. Notably, around the same time, he also developed generalized subcutaneous fat loss of both upper and lower extremities, chest, abdomen, and face that persisted after treatment of the HLH. Whole exome sequencing was performed to search for pathogenic variants that are associated with SPTCL, including those in hepatitis A virus cellular receptor 2 (HAVCR2), but did not detect any potential disease-causing variant. Our report brings to the attention a novel subtype of panniculitis-variety of AGL. Whether generalized loss of subcutaneous fat in this patient is due to lymphoma-associated panniculitis or due to development of adipose tissue-directed autoantibodies as a paraneoplastic "autoimmune" manifestation of SPTCL remains unclear.

Gestational and neonatal outcomes of women with partial Dunnigan lipodystrophy

Introduction

Lipodystrophies are a group of disorders characterized by selective and variable loss of adipose tissue, which can result in an increased risk of insulin resistance and its associated complications. Women with lipodystrophy often have a high frequency of polycystic ovary syndrome (PCOS) and may experience gynecological and obstetric complications. The objective of this study was to describe the gestational outcomes of patients with familial partial lipodystrophy type 2 (FPLD2) at a reference center with the aim of improving the understanding and management of pregnant women affected by this condition.

Methods

This was a retrospective analysis of data obtained from questionnaires regarding past pregnancies and a review of medical records from the beginning of follow-up in outpatient clinics.

Results

All women diagnosed with FPLD2 who had previously become pregnant were included in this study (n=8). The women in the study experienced pregnancies between the ages of 14 and 38 years, with an average of 1.75 children per woman. The pregnancies in question were either the result of successful conception within 12 months of attempting to conceive or unplanned pregnancies. During pregnancy, two women (25%) were diagnosed with gestational diabetes mellitus (GDM), one (12.5%) with gestational hypothyroidism, and one (12.5%) with preeclampsia. Among the 17 pregnancies, two miscarriages (11.8%) occurred, and five cases (29.4%) of macrosomia were observed. Four instances of premature birth and an equal number of neonatal hypoglycemia cases were recorded. The reported neonatal complications included an unspecified malformation, respiratory infection, and two neonatal deaths related to heart malformation and respiratory distress syndrome.

Conclusion

Our data showed a high frequency of fetal complications in women with FPLD2. However, no instances of infertility or prolonged attempts to conceive have been reported, highlighting the significance of employing effective contraception strategies to plan pregnancies at optimal times for managing metabolic comorbidities.

Familial Screening for the Prevention of Rare Diseases: A Focus on Lipodystrophy in Southern Saudi Arabia

BACKGROUND

Lipodystrophy is a relatively rare, complex disease characterised by a deficiency of adipose tissue and can present as either generalised lipodystrophy (GLD) or partial lipodystrophy (PLD). The prevalence of this disease varies by region. This study aimed to identify the genetic variations associated with lipodystrophy in the southern part of Saudi Arabia.

METHODOLOGY

 We conducted a retrospective study by recruiting nine patients from six families, recruiting the proband whole exome sequencing results or any other genetic test results, screening other family members using Sanger sequencing and analysing the carrier status of the latter. These patients were recruited from the Endocrinology and Diabetes Clinic at Jazan General Hospital and East Jeddah Hospital, both in the Kingdom of Saudi Arabia.

RESULT

Eight patients were diagnosed with GLD, and one was diagnosed with PLD. Of the six families, four were consanguineously married from the same tribe, while the remaining belonged to the same clan. The majority of GLD patients had an AGPAT2 c.158del mutation, but some had a BSCL2 c.942dup mutation. The single PLD case had a PPARG c.1024C > T mutation but no family history of the disease. In all families evaluated in this study, some family members were confirmed to be carriers of the mutation observed in the corresponding patient.

CONCLUSION

 Familial screening of relatives of patients with rare, autosomal recessive diseases, such as lipodystrophy, especially when there is a family history, allows the implementation of measures to prevent the onset or reduced severity of disease and reduces the chances of the pathogenic allele being passed onto future generations. Creating a national registry of patients with genetic diseases and carriers of familial pathogenic alleles will allow the assessment of preventive measures and accelerate disease intervention via gene therapy.

Adipose failure through adipocyte overload and autoimmunity

Metabolic syndrome poses a great worldwide threat to the health of the patients. Increased visceral adiposity is recognized as the main determinant of the detrimental clinical effects of insulin resistance. Inflammation and immune system activation in the adipose tissue (AT) have a central role in the pathophysiology of metabolic syndrome, but the mechanisms linking increased adiposity to immunity in the AT remain in part elusive. In this review, we support the central role of adipocyte overload and relative adipose failure as key determinants in triggering immune aggression to AT. This provides a mechanistic explanation of the relative metabolic wellness of metabolically normal obese people and the disruption in insulin signaling in metabolically obese lean people.

Lipid Droplets Accumulation in the Brain of HIV Transgenic Rat: Implication in the Accelerated Aging of HIV Infected Individuals

Abnormal microglial activation has been suggested as "driven force" promoting brain aging. Lipid droplets accumulating microglia (LDAM), identified as a novel inflammatory phenotype, elevate neuroinflammation and exaggerate neuronal injuries in aging and multiple neurodegenerative diseases. Since chronic HIV (human immunodeficiency virus) (+) individuals show an accelerated brain aging and higher incidence of neurological symptoms compared to age-matched HIV (-) population, we hypothesize that LDAM are also involved in such phenomenon. For validating the hypothesis, we employed HIV transgenic (HIV-Tg) and wilt type (WT) rats to check lipid droplets (LDs) accumulation in the brains at mature (6 months) and middle age (12 months). Our results showed that HIV-Tg rats possess higher levels of LDs formation in the hippocampus (HP) and prefrontal cortex (PFc) than controls at middle age. Increased LDs are mainly presented in microglia in the HP but largely co-localized with astrocytes in the PFc. Interestingly, increased LDs are associated with upregulation on Iba1 but not with GFAP levels. HIV-Tg rats reveal an accelerated LDs accumulation during normal aging. Purified microglia from HIV-Tg rats (12 month) show higher expression of neuroimmune signaling than microglia from controls. HIV-Tg rats showed dysregulation on cholesterol synthesis in the brain HP as well as deficiency on locomotion coordination compared to controls. Overall, our results demonstrate substantial LDs accumulation in the brains of HIV-Tg rats which is associated with abnormal microglial activation and accelerated decline on locomotion coordination during aging. Dysregulation on lipid metabolism might underlie accelerated brain aging in the context of chronic HIV infection.

Sphingosine 1-Phosphate Regulates Obesity and Glucose Homeostasis

One of the major global health and welfare issues is the treatment of obesity and associated metabolic disorders, such as type 2 diabetes mellitus and nonalcoholic fatty liver disease. Obesity, caused by the excessive accumulation of triglycerides in adipose tissues, induces adipocyte dysfunction, followed by inflammation, in adipose tissues and lipotoxicity in nonadipose tissues. Several studies have shown that obesity and glucose homeostasis are influenced by sphingolipid mediators, including ceramide and sphingosine 1-phosphate (S1P). Cellular accumulation of ceramide impairs pancreatic β-cell survival, confers insulin resistance in the liver and the skeletal muscle, and deteriorates adipose tissue inflammation via unknown molecular mechanisms. The roles of S1P are more complicated, because there are five cell-surface S1P receptors (S1PRs: S1P1-5) which have altered functions, different cellular expression patterns, and inapparent intracellular targets. Recent findings, including those by our group, support the notable concept that the pharmacological activation of S1P1 or S1P3 improves obesity and associated metabolic disorders, whereas that of S1P2 has the opposite effect. In addition, the regulation of S1P production by sphingosine kinase (SphK) is an essential factor affecting glucose homeostasis. This review summarizes the current knowledge on SphK/S1P/S1PR signaling in and against obesity, insulin resistance, and associated disorders.

Impact of lipodystrophy on health-related quality of life: the QuaLip study

BACKGROUND

Lipodystrophy is a rare disease characterized by loss of adipose tissue. Natural history studies have demonstrated significant burden of disease; however, there is limited data on the impact of lipodystrophy on quality of life (QoL) and psychoemotional well-being. The QuaLip study is a prospective observational real-world study that aims to determine the impact of lipodystrophy on QoL and psychoemotional well-being and explore subjective burden of the disease. Sixty-seven adult patients and eight pediatric patients with lipodystrophy were included. Patients were followed up for 24 months and assessments were repeated every three months. Patients were examined by licensed psychiatrists at baseline, and at year 1 and year 2 visits.

RESULTS

Eighteen (27.69%) of 65 adult patients (two subjects refused psychiatric assessment) were diagnosed with a psychiatric disorder (e.g., depressive episodes, mixed anxiety and depressive disorder, anxiety disorder, adjustment disorder, recurrent depression, panic disorder, generalized anxiety disorder, unspecified mood disorder, nonorganic sleep disorder, post-traumatic stress disorder, depressive episode comorbidity, social phobia and obsessive-compulsive disorder comorbidity). Lipodystrophy disease and QoL questionnaires revealed a significant disease burden over the study period. More than one-third of patients reported depression symptoms on the Beck Depression Inventory and more than one-fourth of the patients reported significant hunger throughout the study period. Physical appearance, fatigue, and pain contributed to the disease burden. QoL scores were lower in patients with psychiatric disease and in those with poor metabolic control. Attention deficit hyperactivity disorder, depressive disorder, sub-threshold depressive symptoms, obsessive-compulsive disorder, appetite problems, and issues with physical appearance were identified in selected pediatric subjects.

CONCLUSIONS

Lipodystrophy has a significant impact on QoL and psychoemotional well-being. Psychiatric disorders seem to be underdiagnosed among patients with lipodystrophy.

Natural history and comorbidities of generalised and partial lipodystrophy syndromes in Spain

The rarity of lipodystrophies implies that they are not well-known, leading to delays in diagnosis/misdiagnosis. The aim of this study was to assess the natural course and comorbidities of generalised and partial lipodystrophy in Spain to contribute to their understanding. Thus, a total of 140 patients were evaluated (77.1% with partial lipodystrophy and 22.9% with generalised lipodystrophy). Clinical data were collected in a longitudinal setting with a median follow-up of 4.7 (0.5-17.6) years. Anthropometry and body composition studies were carried out and analytical parameters were also recorded. The estimated prevalence of all lipodystrophies in Spain, excluding Köbberling syndrome, was 2.78 cases/million. The onset of phenotype occurred during childhood in generalised lipodystrophy and during adolescence-adulthood in partial lipodystrophy, with the delay in diagnosis being considerable for both cohorts. There are specific clinical findings that should be highlighted as useful features to take into account when making the differential diagnosis of these disorders. Patients with generalised lipodystrophy were found to develop their first metabolic abnormalities sooner and a different lipid profile has also been observed. Mean time to death was 83.8 ± 2.5 years, being shorter among patients with generalised lipodystrophy. These results provide an initial point of comparison for ongoing prospective studies such as the ECLip Registry study.

Loss of phospholipase PLAAT3 causes a mixed lipodystrophic and neurological syndrome due to impaired PPARγ signaling

Phospholipase A/acyltransferase 3 (PLAAT3) is a phospholipid-modifying enzyme predominantly expressed in neural and white adipose tissue (WAT). It is a potential drug target for metabolic syndrome, as Plaat3 deficiency in mice protects against diet-induced obesity. We identified seven patients from four unrelated consanguineous families, with homozygous loss-of-function variants in PLAAT3, who presented with a lipodystrophy syndrome with loss of fat varying from partial to generalized and associated with metabolic complications, as well as variable neurological features including demyelinating neuropathy and intellectual disability. Multi-omics analysis of mouse Plaat3-/- and patient-derived WAT showed enrichment of arachidonic acid-containing membrane phospholipids and a strong decrease in the signaling of peroxisome proliferator-activated receptor gamma (PPARγ), the master regulator of adipocyte differentiation. Accordingly, CRISPR-Cas9-mediated PLAAT3 inactivation in human adipose stem cells induced insulin resistance, altered adipocyte differentiation with decreased lipid droplet formation and reduced the expression of adipogenic and mature adipocyte markers, including PPARγ. These findings establish PLAAT3 deficiency as a hereditary lipodystrophy syndrome with neurological manifestations, caused by a PPARγ-dependent defect in WAT differentiation and function.

Regulatory mechanisms underlying endoplasmic reticulum stress involvement in the development of gestational diabetes mellitus entail the CHOP-PPARα-NF-κB pathway

OBJECTIVE

We investigated the proinflammatory functions of endoplasmic reticulum stress and peroxisome proliferator-activated receptor α (PPARα) in the development of gestational diabetes mellitus (GDM) and their relationship in regulating inflammation in GDM.

METHODS

This study was performed on placentas of normal pregnant women, women with GDM, and HTR8 cells. Transmission electron microscopy, immunohistochemistry, Western blot analysis, and RT-PCR were performed to analyze ERS and PPARα expression on both normal and GDM pregnancy placentas. ELISA was performed to analyze inflammatory biomarkers. To generate models of the GDM-like state, placentas of normal pregnancy were treated with LPS and polyinosinic-polycytidylic acid (poly [I:C]). TG, CHOP plasmid, and CHOP siRNA were assessed as to their regulation of HTR8 cells to discern the relationship between ERS and PPARα in regulating the inflammation associated with GDM.

RESULTS

ERS was elevated in GDM placentas, induced the secretion of IL-6 and TNF-α, and attenuated the expression of GLUT-4. PPARα was diminished in GDM placentas and inhibited the inflammatory responses via the NF-κB nuclear-transport process. 4-PBA reduced CHOP and augmented PPARα, and it decreased IL-6 and TNF-α in our GDM-like explant. However, with both 4-PBA and MK886 treatment, we noted no significant difference in CHOP expression. The level of PPARα was reduced, and that of NF-κB p65 in the nucleus was elevated with TG treatment in the HTR8/Svneo. Knockdown of CHOP increased PPARα and reduced NF-κB p65, while expression of PPARα declined, and that of NF-κB p65 rose with the application of CHOP when HTR8 cells were treated with TG.

CONCLUSIONS

ERS contributes to the pathophysiology of GDM in pregnancy via the CHOP-PPARα-NF-κB-signalling pathway by inducing aberrant activation of inflammation and insulin resistance.

Radiographic appearances of a continuous glucose monitor in a patient with lipodystrophy

We report the case of a 50-year old woman with a known history of lipodystrophy. A pelvic radiograph was taken for the investigation of right hip pain. The image shown demonstrates an indeterminate artefact projected over the right iliac fossa. A previous CT renal study was reviewed, demonstrating the same device in the subcutaneous tissues of the contralateral left lower quadrant which on close inspection was consistent with a continuous glucose monitoring device. Features of lipodystrophy were also noted on review of the CT imaging. Although many devices such as vagal stimulators and prosthetic valves are easily recognized by radiologists on radiographic images, they may be less familiar with devices such as continuous glucose monitors. The aim of this case report is to familiarize radiologists with the appearances of continuous glucose monitors to allow for effective reporting.

Endocrine immune-related adverse effects of immune-checkpoint inhibitors

INTRODUCTION

Immune-checkpoint inhibitor therapy modulates the response of the immune system acting against cancer. Two pathways impacted by this kind of treatment are the CTLA4 and the PD-1/PD-L1 pathways. ICI therapy can trigger autoimmune adverse effects, known as immune-related Adverse Events (irAEs).

AREAS COVERED

This review focuses on irAEs which affect the endocrine system. This review elucidates the pathways used by these drugs with a focus on the hypothetical pathogenesis at their basis. In fact, the pathophysiology of irAEs concerns the possibility of an interaction between cellular autoimmunity, humoral immunity, cytokines, chemokines, and genetics. The endocrine irAEs examined are thyroid dysfunctions, immune related-hypophysitis, diabetes, peripheral adrenal insufficiency, and hypoparathyroidism.

EXPERT OPINION

There is still much to investigate in endocrine irAES of checkpoint inhibitors. In the future, checkpoint inhibitors will be increasingly utilized therapies, and therefore it is crucial to find the proper diagnostic-therapeutic program for irAEs, especially as endocrine irAEs are nonreversible and require lifelong replacement therapies.

Metreleptin Treatment in a Boy with Congenital Generalized Lipodystrophy due to Homozygous c.465_468delGACT (p.T156Rfs*8) Mutation in the BSCL2 Gene: Results From the First-year

Congenital generalized lipodystrophy (CGL) is a rare, autosomal recessive disorder characterized by an almost complete absence of body fat. In CGL, patients may have hyperphagia due to leptin deficiency. Recombinant human leptin (metreleptin) has been suggested as an effective treatment option. We present successful treatment with metreleptin in a boy with CGL and results from the first year of follow-up. An eight-month-old boy presented with excessive hair growth and a muscular appearance. On examination he had hypertrichosis, decreased subcutaneous adipose tissue over the whole body and hepatomegaly. Laboratory investigations revealed hypertriglyceridemia, hyperinsulinemia, elevated liver transaminases and low leptin levels. Molecular genetic analysis detected a homozygous, c.465_468delGACT (p.T156Rfs*8) mutation in the BSCL2 gene. A diagnosis of CGL type 2 was considered. Despite dietary intervention, exercise, and treatment with additional omega-3 and metformin, the hypertriglyceridemia, hyperinsulinemia, and elevated liver transaminase levels worsened. Metreleptin treatment was started and after one year hyperphagia had disappeared, and there was dramatic improvement in levels of insulin, hemoglobin A1c, triglycerides and liver transaminases. Hepatosteatosis was lessened and hepatosplenomegaly was much improved. Metreleptin appears to be an effective treatment option in children with CGL that remarkably improved metabolic complications in the presented case. Initiation of metreleptin treatment in the early period may decrease mortality and morbidity, and increase the quality of life in children with CGL.

Refining Evaluation of Bone Mass and Adipose Distribution in Dunnigan Syndrome

Familial partial lipodystrophies (FPLD) are rare diseases characterized by selective loss of subcutaneous adipose tissue at different sites. This cross-sectional observational study aimed to estimate adipose tissue in the bone marrow (BMAT), intra (IMCL) and extra-myocyte lipids (EMCL), and define the bone phenotype in the context of FPLD2/Dunnigan syndrome (DS). The subjects comprised 23 controls (C) and 18 DS patients, matched by age, weight and height. Blood samples, dual-energy X-ray absorptiometry for bone mineral density (BMD) and trabecular bone score (TBS) and 1H-spectroscopy using magnetic resonance to estimate BMAT in the lumbar spine, IMCL, EMCL and osteoclastogenesis were assessed. The prevalence of diabetes mellitus was 78% in DS patients. Glucose, HbA1c, triglycerides, insulin and HOMA-IR levels were elevated in DS, whereas HDLc, 25(OH)D, PTH and osteocalcin levels were reduced. BMD was similar between groups at all sites, except 1/3 radius, which was lower in DS group. TBS was reduced in DS. DS presented increased osteoclastogenesis and elevated BMAT, with greater saturation levels and higher IMCL than the C group. HOMA-IR and EMCL were negatively associated with TBS; osteocalcin and EMCL were correlated negatively with BMD. This study contributes to refining the estimation of adipose tissue in DS by showing increased adiposity in the lumbar spine and muscle tissue. DXA detected lower TBS and BMD in the 1/3 radius, suggesting impairment in bone quality and that bone mass is mainly affected in the cortical bone.

Metreleptin Robustly Increases Resting-state Brain Connectivity in Treatment-naïve Female Patients With Lipodystrophy

Context

Research in lipodystrophy (LD) and its treatment with metreleptin has not only helped patients with LD but has opened new directions in investigating leptin's role in metabolism and the regulation of eating behavior. Previously, in a study with patients with LD undergoing metreleptin treatment using functional magnetic resonance imaging (MRI), we found significantly increased resting-state brain connectivity in 3 brain areas including the hypothalamus.

Objective

In this study, we aimed to reproduce our functional MRI findings in an independent sample and compare results to healthy participants.

Design

Measurements in 4 female patients with LD undergoing metreleptin treatment and 3 healthy untreated controls were performed at 4 different time points over 12 weeks. To identify treatment-related brain connectivity alterations, eigenvector centrality was computed from resting-state functional MRI data for each patient and each session. Thereafter, analysis aimed at detecting consistent brain connectivity changes over time across all patients.

Results

In parallel to metreleptin treatment of the patients with LD, we found a significant brain connectivity increase in the hypothalamus and bilaterally in posterior cingulate gyrus. Using a 3-factorial model, a significant interaction between group and time was found in the hypothalamus.

Conclusions

Investigating brain connectivity alterations with metreleptin treatment using an independent sample of patients with LD, we have reproduced an increase of brain connectivity in hedonic and homeostatic central nervous networks observed previously with metreleptin treatment. These results are an important contribution to ascertain brain leptin action and help build a foundation for further research of central nervous effects of this important metabolic hormone.

Clinical features of generalized lipodystrophy in Turkey: A cohort analysis

AIM

To describe the Turkish generalized lipodystrophy (GL) cohort with the frequency of each complication and the death rate during the period of the follow-up.

METHODS

This study reports on 72 patients with GL (47 families) registered at different centres in Turkey that cover all regions of the country. The mean ± SD follow-up was 86 ± 78 months.

RESULTS

The Kaplan-Meier estimate of the median time to diagnosis of diabetes and/or prediabetes was 16 years. Hyperglycaemia was not controlled in 37 of 45 patients (82.2%) with diabetes. Hypertriglyceridaemia developed in 65 patients (90.3%). The Kaplan-Meier estimate of the median time to diagnosis of hypertriglyceridaemia was 14 years. Hypertriglyceridaemia was severe (≥ 500 mg/dl) in 38 patients (52.8%). Seven (9.7%) patients suffered from pancreatitis. The Kaplan-Meier estimate of the median time to diagnosis of hepatic steatosis was 15 years. Liver disease progressed to cirrhosis in nine patients (12.5%). Liver disease was more severe in congenital lipodystrophy type 2 (CGL2). Proteinuric chronic kidney disease (CKD) developed in 32 patients (44.4%) and cardiac disease in 23 patients (31.9%). Kaplan-Meier estimates of the median time to diagnosis of CKD and cardiac disease were 25 and 45 years, respectively. Females appeared to have a more severe metabolic disease, with an earlier onset of metabolic abnormalities. Ten patients died during the follow-up period. Causes of death were end-stage renal disease, sepsis (because of recurrent intestinal perforations, coronavirus disease, diabetic foot infection and following coronary artery bypass graft surgery), myocardial infarction, heart failure because of dilated cardiomyopathy, stroke, liver complications and angiosarcoma.

CONCLUSIONS

Standard treatment approaches have only a limited impact and do not prevent the development of severe metabolic abnormalities and early onset of organ complications in GL.

Beyond BMI

This review examined the origins of the concept of the BMI in the work of Quetelet in the 19th century and its subsequent adoption and use in tracking the course of the pandemic of obesity during the 20th century. In this respect, it has provided a valuable international epidemiological tool that should be retained. However, as noted in this review, the BMI is deficient in at least three ways. First, it does not measure body fat distribution, which is probably a more important guide to the risk of excess adiposity than the BMI itself. Second, it is not a very good measure of body fat, and thus its application to the diagnosis of obesity or excess adiposity in the individual patient is limited. Finally, the BMI does not provide any insights into the heterogeneity of obesity or its genetic, metabolic, physiological or psychological origins. Some of these mechanisms are traced in this review.

Impact of Combined Baricitinib and FTI Treatment on Adipogenesis in Hutchinson-Gilford Progeria Syndrome and Other Lipodystrophic Laminopathies

Hutchinson-Gilford progeria syndrome (HGPS) is a rare genetic disease that causes premature aging symptoms, such as vascular diseases, lipodystrophy, loss of bone mineral density, and alopecia. HGPS is mostly linked to a heterozygous and de novo mutation in the LMNA gene (c.1824 C > T; p.G608G), resulting in the production of a truncated prelamin A protein called "progerin". Progerin accumulation causes nuclear dysfunction, premature senescence, and apoptosis. Here, we examined the effects of baricitinib (Bar), an FDA-approved JAK/STAT inhibitor, and a combination of Bar and lonafarnib (FTI) treatment on adipogenesis using skin-derived precursors (SKPs). We analyzed the effect of these treatments on the differentiation potential of SKPs isolated from pre-established human primary fibroblast cultures. Compared to mock-treated HGPS SKPs, Bar and Bar + FTI treatments improved the differentiation of HGPS SKPs into adipocytes and lipid droplet formation. Similarly, Bar and Bar + FTI treatments improved the differentiation of SKPs derived from patients with two other lipodystrophic diseases: familial partial lipodystrophy type 2 (FPLD2) and mandibuloacral dysplasia type B (MADB). Overall, the results show that Bar treatment improves adipogenesis and lipid droplet formation in HGPS, FPLD2, and MADB, indicating that Bar + FTI treatment might further ameliorate HGPS pathologies compared to lonafarnib treatment alone.

Characteristic and fate determination of adipose precursors during adipose tissue remodeling

Adipose tissues are essential for actively regulating systemic energy balance, glucose homeostasis, immune responses, reproduction, and longevity. Adipocytes maintain dynamic metabolic needs and possess heterogeneity in energy storage and supply. Overexpansion of adipose tissue, especially the visceral type, is a high risk for diabetes and other metabolic diseases. Changes in adipocytes, hypertrophy or hyperplasia, contribute to the remodeling of obese adipose tissues, accompanied by abundant immune cell accumulation, decreased angiogenesis, and aberrant extracellular matrix deposition. The process and mechanism of adipogenesis are well known, however, adipose precursors and their fate decision are only being defined with recent information available to decipher how adipose tissues generate, maintain, and remodel. Here, we discuss the key findings that identify adipose precursors phenotypically, with special emphasis on the intrinsic and extrinsic signals in instructing and regulating the fate of adipose precursors under pathophysiological conditions. We hope that the information in this review lead to novel therapeutic strategies to combat obesity and related metabolic diseases.

Lipohypertrophy and Insulin. An Old Dog that Needs New Tricks

OBJECTIVE

To review the current status of practical knowledge related to insulin-associated lipohypertrophy (LH) - an accumulation of fatty subcutaneous nodules commonly caused by repeated injections and/or infusions of insulin into the same site.

METHODS

Review of published literature with additional contributions from leading multidisciplinary experts with the emphasis on clinical aspects including pathophysiology, clinical and economic consequences, diagnosis, prevention and treatment.

RESULTS

LH is the most common dermatologic complication of insulin therapy. Risk factors for the development of lipohypertrophy include repeated delivery of large amounts of insulin into the same location over time, repeated injection trauma to the skin and subcutaneous tissue, and multiple injections using the same needle. Subcutaneous insulin injection in skin areas with lipohypertrophy is associated with reduced pain; however, this problem can interfere with insulin absorption, thereby increasing the likelihood of glucose variability, hypo- and hyperglycemia when a site is changed. Modern visualization technology of the subcutaneous space with ultrasound can demonstrate lipohypertrophy early in the course of its development.

CONCLUSIONS

The physiological and psychological consequences of developing insulin lipohypertrophy can be prevented and treated with education focusing on insulin injection techniques.

Temporal Relationship Between Insulin Resistance and Lipid Accumulation After Bariatric Surgery: a Multicenter Cohort Study

PURPOSE

Insulin resistance (IR) is closely associated with lipid accumulation. Here, we investigated the temporal relationship between the two conditions after bariatric surgery.

MATERIALS AND METHODS

In total, 409 participants were enrolled from three bariatric centers in China from 2009 to 2018. We evaluated whether baseline IR (proxied by homeostasis model assessment of insulin resistance (HOMA-IR)) and lipid accumulation (proxied by visceral adiposity index (VAI) and lipid accumulation product (LAP)) were associated with follow-up IR and lipid accumulation (3 months postoperatively) using linear regression models. We then conducted a cross-lagged panel analysis model to simultaneously examine the bidirectional relationship between IR and lipid accumulation.

RESULTS

Multivariable linear regression analyses showed that baseline HOMA-IR was associated with follow-up VAI (β = 0.430, 95% CI: 0.082-0.778, p = 0.016) and LAP (β = 0.070, 95% CI: 0.010-0.130, p = 0.022). There was no relationship between baseline lipid accumulation and follow-up IR. Further cross-lagged panel analyses indicated that the path coefficient from baseline HOMA-IR to follow-up VAI (β₂ = 0.145, p = 0.003) was significantly greater than the coefficient from baseline VAI to follow-up HOMA-IR (β₁ =  - 0.013, p = 0.777). Similarly, the path coefficient from baseline HOMA-IR to follow-up LAP (β₂ = 0.141, p = 0.003) was significantly greater than the coefficient from baseline LAP to follow-up HOMA-IR (β₁ = 0.041, p = 0.391).

CONCLUSION

Our study demonstrated a unidirectional relationship from HOMA-IR to VAI and LAP, suggesting that the change in IR may precede lipid accumulation after surgery.

Marked Hypoleptinemia Precedes Overt Fat Loss in Immune Checkpoint Inhibitor-induced Acquired Generalized Lipodystrophy

Immune checkpoint inhibitors (ICIs) targeting cancer cells that evade immune T-cell regulation have revolutionized the treatment of metastatic carcinomas. Unfortunately, secondary endocrinopathies associated with ICI, including adrenal insufficiency, primary hypothyroidism, autoimmune diabetes, and rarely hypoparathyroidism, are increasing. Lipodystrophy, presumably due to the autoimmune destruction of adipocytes, leading to metabolic complications, is a less recognized adverse effect of ICI therapy. We present a case of a 66-year-old Caucasian woman treated with pembrolizumab, an anti-programmed death 1 inhibitor, for metastatic lung adenocarcinoma. Fifteen months after the treatment initiation, she was found to have hyperglycemia, hyperlipidemia, and hepatic steatosis but without any evidence of autoimmune diabetes. She was also noted to have isolated buccal fat pad loss, raising suspicion of acquired lipodystrophy. Despite well-preserved subcutaneous fat over the trunk and limbs, she had undetectable serum leptin levels. Whole-body fluorodeoxyglucose (FDG)-positron emission tomography scan showed diffuse mild FDG activity throughout the subcutaneous tissue, suggesting underlying inflammation. Over the next 3 months, she developed progressive fat loss leading to generalized lipodystrophy. Adipose tissue dysfunction, secondary to ICI-induced subclinical panniculitis, precedes overt fat loss and is characterized by hypoleptinemia and metabolic abnormalities.

Pelvis magnetic resonance imaging to diagnose familial partial lipodystrophy

CONTEXT

The diagnosis of familial partial lipodystrophy (FPLD) is currently made based on clinical judgement.

OBJECTIVE

There is a need for objective diagnostic tools that can diagnose FPLD accurately.

METHODS

We have developed a new method that used measurements from pelvic magnetic resonance imaging (MRI) at the pubis level. We evaluated measurements from a lipodystrophy cohort (n = 59; median age [25-75 percentiles]: 32 [24-44]; 48 females and 11 males) and age- and gender-matched controls (n = 29). Another dataset included MRIs from 289 consecutive patients.

RESULTS

Receiver operating characteristic curve (ROC) analysis revealed a potential cut-point of ≤ 13 mm gluteal fat thickness for the diagnosis of FPLD. A combination of gluteal fat thickness ≤ 13 mm and pubic/gluteal fat ratio ≥ 2.5 (based on a ROC) provided 96.67% (95% Confidence Interval [CI]: 82.78-99.92%) sensitivity and 91.38% (95% CI: 81.02-97.14%) specificity in the overall cohort and 100.00% (95% CI: 87.23-100.00%) sensitivity and 90.00% (95% CI: 76.34-97.21%) specificity in females for the diagnosis of FPLD. When this approach was tested in a larger dataset of random patients, FPLD was differentiated from subjects without lipodystrophy with 96.67% (95% CI: 82.78-99.92%) sensitivity and 100.00% (95% CI: 98.73-100.00%) specificity. When only women were analyzed, the sensitivity and the specificity was 100.00% (95%CI: 87.23-100.00% and 97.95-100.00%, respectively). The performance of gluteal fat thickness and pubic/gluteal fat thickness ratio was comparable to readouts performed by radiologists with expertise in lipodystrophy.

CONCLUSION

The combined use of gluteal fat thickness and pubic/gluteal fat ratio from pelvic MRI is a promising method to diagnose FPLD that can reliably identify FPLD in women. Our findings need to be tested in larger populations and prospectively.