Lipodystrophy Syndromes

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.

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.

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.

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.

The role of hepatokines in NAFLD

Non-alcoholic fatty liver disease (NAFLD) is not only a consequence of insulin resistance, but it is also an important cause of insulin resistance and major non-communicable diseases (NCDs). The close relationship of NAFLD with visceral obesity obscures the role of fatty liver from visceral adiposity as the main pathomechanism of insulin resistance and NCDs. To overcome this limitation, in analogy to the concept of adipokines, in 2008 we introduced the term hepatokines to describe the role of fetuin-A in metabolism. Since then, several other hepatokines were tested for their effects on metabolism. Here we address the dysregulation of hepatokines in people with NAFLD. Then, we discuss pathophysiological mechanisms of cardiometabolic diseases specifically related to NAFLD by focusing on hepatokine-related organ crosstalk. Finally, we propose how the determination of major hepatokines and adipokines can be used for pathomechanism-based clustering of insulin resistance in NAFLD and visceral obesity to better implement precision medicine in clinical practice.

The interaction of T2DM and BMI with NASH in recipients of liver transplants: an SRTR database analysis

BACKGROUND

NASH-related liver transplants are increasing because of the obesity epidemic, but the influence of T2DM on various levels of BMI among NASH recipients is unclear.

RESEARCH DESIGN AND METHODS

We analyzed data retrieved from SRTR on 4,515 patients. We divided patients by BMI into five groups: normal weight; overweight; class 1 obesity; class 2 obesity; and class 3 obesity. Statistical analysis was done.

RESULTS

Patients in the NASH group with T2DM had a lower patient and graft survival than patients without T2DM (5-year patient and graft survival: 77.5% vs. 79.8%; P = 0.001 and 76.4% vs. 78.2%; P = 0.002, respectively). Multivariate Cox proportional regression showed an independent association between T2DM and decreased patient and graft survival (HR, 1.170; P = 0.015 and HR, 1.133; P = 0.048, respectively). In the lean and the class 3 obesity NASH groups, patients with T2DM had lower patient and graft survival than the patients without T2DM. In the class 3 obesity NASH group, T2DM was independently associated with decreased patient survival (HR, 1.581; P = 0.027).

CONCLUSION

Our research reveals that the focus of the post-transplantation treatment should be different for different BMI patients.

Autoantibodies to Perilipin-1 Define a Subset of Acquired Generalized Lipodystrophy

Acquired lipodystrophy is often characterized as an idiopathic subtype of lipodystrophy. Despite suspicion of an immune-mediated pathology, biomarkers such as autoantibodies are generally lacking. Here, we used an unbiased proteome-wide screening approach to identify autoantibodies to the adipocyte-specific lipid droplet protein perilipin 1 (PLIN1) in a murine model of autoimmune polyendocrine syndrome type 1 (APS1). We then tested for PLIN1 autoantibodies in human subjects with acquired lipodystrophy with two independent severe breaks in immune tolerance (including APS1) along with control subjects using a specific radioligand binding assay and indirect immunofluorescence on fat tissue. We identified autoantibodies to PLIN1 in these two cases, including the first reported case of APS1 with acquired lipodystrophy and a second patient who acquired lipodystrophy as an immune-related adverse event following cancer immunotherapy. Lastly, we also found PLIN1 autoantibodies to be specifically enriched in a subset of patients with acquired generalized lipodystrophy (17 of 46 [37%]), particularly those with panniculitis and other features of autoimmunity. These data lend additional support to new literature that suggests that PLIN1 autoantibodies represent a marker of acquired autoimmune lipodystrophies and further link them to a break in immune tolerance.

PPARγ Gene as a Possible Link between Acquired and Congenital Lipodystrophy and its Modulation by Dietary Fatty Acids

Lipodystrophy syndromes are rare diseases that could be of genetic or acquired origin. The main complication of lipodystrophy is the dysfunction of adipose tissue, which leads to an ectopic accumulation of triglycerides in tissues such as the liver, pancreas and skeletal muscle. This abnormal fat distribution is associated with hypertriglyceridemia, insulin resistance, liver steatosis, cardiomyopathies and chronic inflammation. Although the origin of acquired lipodystrophies remains unclear, patients show alterations in genes related to genetic lipodystrophy, suggesting that this disease could be improved or aggravated by orchestrating gene activity, for example by diet. Nowadays, the main reason for adipose tissue dysfunction is an imbalance in metabolism, caused in other pathologies associated with adipose tissue dysfunction by high-fat diets. However, not all dietary fats have the same health implications. Therefore, this article aims to summarize the main genes involved in the pathophysiology of lipodystrophy, identify connections between them and provide a systematic review of studies published between January 2017 and January 2022 of the dietary fats that can modulate the development of lipodystrophy through transcriptional regulation or the regulation of protein expression in adipocytes.

Differential loss of fat in polycystic ovary syndrome: A welcome or warning sign?

Lipodystrophy syndrome is a rare disorder characterized by selective deficiency of adipose tissue and severe insulin resistance resulting in metabolic complications. Its presentation as polycystic ovary disease (PCOD) is even rarer. We present a 23-year-old woman who came with complaints of oligomenorrhoea and hirsutism. When specifically asked, she accepted noticing loss of fat from some areas of her body. Examination showed loss of fat from the face, buttocks and thighs. Her investigations revealed deranged blood sugars, transaminitis, dyslipidaemia and elevated serum testosterone; ultrasonography showed fatty liver and polycystic ovary. Fat composition measurement revealed loss of fat from lower limbs and increased ratio of trunk-to-leg fat. Based on these findings, a diagnosis of lipodystrophy was made. She was started on metformin, statins and ursodeoxycholic acid. Blood sugars, lipid profile and dyslipidaemia improved over a period of 6 months. We suggest that in lean patients with PCOD, lipodystrophy becomes a differential diagnosis, so attention should be paid to body fat distribution in them. Despite normal body mass index (BMI), these patients tend to develop metabolic complications as in our patient (BMI 21.5). This diagnosis has long-term implications in view of its association with metabolic complications.

Lipodystrophies in Children

BACKGROUND

Lipodystrophy includes a wide group of diseases characterized by reduction, absence, or altered distribution of adipose tissue. Lipodystrophies are classified into generalized or partial, according to the fat distribution, and congenital or acquired, considering the etiology.

SUMMARY

Impaired glucose and lipid metabolism are typically present, thus severe insulin resistance, diabetes mellitus, dyslipidemia, and hepatic steatosis are frequent complications. Because of the rarity and the diversification of lipodystrophies, diagnosis might be challenging, typically for partial forms that cannot be easily recognized, leading to progression of the several metabolic abnormalities associated. First management of lipodystrophy is diet and lifestyle changes, followed by the treatment of metabolic complications. Replacement therapy with metreleptin, currently available in the USA and Europe, has shown improvement of metabolic profile in a great number of patients with lipodystrophy.

KEY MESSAGES

The purpose of this review was to describe the phenotypic characteristics of all the known lipodystrophic types and to present specific steps for obtaining an early diagnosis and assessing the best treatment of lipodystrophy.

The role of hypoleptinemia in the psychological and behavioral adaptation to starvation: implications for anorexia nervosa

This narrative review aims to pinpoint mental and behavioral effects of starvation, which may be triggered by hypoleptinemia and as such may be amenable to treatment with leptin receptor agonists. The reduced leptin secretion results from the continuous loss of fat mass, thus initiating a graded triggering of diverse starvation related adaptive functions. In light of leptin receptors located in several peripheral tissues and many brain regions adaptations may extend beyond those of the hypothalamus-pituitary-end organ-axes. We focus on gastrointestinal tract and reward system as relevant examples of peripheral and central effects of leptin. Despite its association with extreme obesity, congenital leptin deficiency with its many parallels to a state of starvation allows the elucidation of mental symptoms amenable to treatment with exogenous leptin in both ob/ob mice and humans with this autosomal recessive disorder. For starvation induced behavioral changes with an intact leptin signaling we particularly focus on rodent models for which proof of concept has been provided for the causative role of hypoleptinemia. For humans, we highlight the major cognitive, emotional and behavioral findings of the Minnesota Starvation Experiment to contrast them with results obtained upon a lesser degree of caloric restriction. Evidence for hypoleptinemia induced mental changes also stems from findings obtained in lipodystrophies. In light of the recently reported beneficial cognitive, emotional and behavioral effects of metreleptin-administration in anorexia nervosa we discuss potential implications for the treatment of this eating disorder. We postulate that leptin has profound psychopharmacological effects in the state of starvation.

Post-acute cardiac complications following SARS-CoV-2 infection in partial lipodystrophy due to LMNA gene p.R349W mutation

PURPOSE

SARS-CoV-2 infection may cause varying degrees of cardiac injury and the presence of underlying cardiovascular morbidities contributes to the frequency and severity of occurrence of this complication. Lipodystrophy syndromes are frequently characterized by severe metabolic derangements that represent relevant cardiovascular risk factors. Besides causing lipodystrophy, mutations in the lamin A/C (LMNA) gene can lead to a wide spectrum of tissue-specific disorders including cardiac involvement.

METHODS AND RESULTS

We herein examine the case of two patients affected by atypical progeroid syndrome and partial lipodystrophy due to a heterozygous missense LMNA mutation c.1045 C > T (p.R349W) who presented initially with mild COVID-19 and developed severe cardiovascular complications within few weeks of SARS-CoV-2 infection. Before being infected with SARS-CoV-2, our patients had cardiovascular morbidities (mild mitral regurgitation in one patient, ischemic heart disease with bifascicular block in the other patient) in adjunct to cardiovascular risk factors, but the SARS-CoV-2 infection contributed to quickly and significantly decompensate their balance.

CONCLUSION

These findings warn that patients affected by LMNA p.R349W mutation and likely other LMNA mutations associated with cardiovascular morbidity should be considered at extremely elevated risk of post-acute cardiological manifestations and should therefore undergo a vigilant follow-up after SARS-CoV-2 infection. Both patients developed COVID-19 before the specific vaccination was available to them and this unfortunate situation should remark the importance of vaccination coverage against SARS-CoV-2 infection for all patients affected by lipodystrophy, especially those with underlying comorbidities.

Suppression of Anti-Inflammatory Mediators in Metabolic Disease May Be Driven by Overwhelming Pro-Inflammatory Drivers

Obesity is a multifactorial disease and is associated with an increased risk of developing metabolic syndrome and co-morbidities. Dysregulated expansion of the adipose tissue during obesity induces local tissue hypoxia, altered secretory profile of adipokines, cytokines and chemokines, altered profile of local tissue inflammatory cells leading to the development of low-grade chronic inflammation. Low grade chronic inflammation is considered to be the underlying mechanism that increases the risk of developing obesity associated comorbidities. The glucocorticoid induced protein annexin A1 and its N-terminal peptides are anti-inflammatory mediators involved in resolving inflammation. The aim of the current study was to investigate the role of annexin A1 in obesity and associated inflammation. To achieve this aim, the current study analysed data from two feasibility studies in clinical populations: (1) bariatric surgery patients (Pre- and 3 months post-surgery) and (2) Lipodystrophy patients. Plasma annexin A1 levels were increased at 3-months post-surgery compared to pre-surgery (1.2 ± 0.1 ng/mL, n = 19 vs. 1.6 ± 0.1 ng/mL, n = 9, p = 0.009) and positively correlated with adiponectin (p = 0.009, r = 0.468, n = 25). Plasma annexin A1 levels were decreased in patients with lipodystrophy compared to BMI matched controls (0.2 ± 0.1 ng/mL, n = 9 vs. 0.97 ± 0.1 ng/mL, n = 30, p = 0.008), whereas CRP levels were significantly elevated (3.3 ± 1.0 µg/mL, n = 9 vs. 1.4 ± 0.3 µg/mL, n = 31, p = 0.0074). The roles of annexin A1 were explored using an in vitro cell based model (SGBS cells) mimicking the inflammatory status that is observed in obesity. Acute treatment with the annexin A1 N-terminal peptide, AC2-26 differentially regulated gene expression (including PPARA (2.8 ± 0.7-fold, p = 0.0303, n = 3), ADIPOQ (2.0 ± 0.3-fold, p = 0.0073, n = 3), LEP (0.6 ± 0.2-fold, p = 0.0400, n = 3), NAMPT (0.4 ± 0.1-fold, p = 0.0039, n = 3) and RETN (0.1 ± 0.03-fold, p < 0.0001, n = 3) in mature obesogenic adipocytes indicating that annexin A1 may play a protective role in obesity and inflammation. However, this effect may be overshadowed by the continued increase in systemic inflammation associated with rapid tissue expansion in obesity.

Approach to the Patient With Moderate Hypertriglyceridemia

Hypertriglyceridemia is a common lipid disorder encountered in clinical practice. Plasma triglycerides are a marker for the concentration of triglycerides carried in chylomicrons and very low-density lipoprotein particles. A fasting triglyceride level <150 mg/dL is accepted widely as the upper limit of normal range. Guidelines for hypertriglyceridemia are variable without a global consensus on classification and goals for triglyceride levels. A general classification of hypertriglyceridemia is mild < 200 mg/dL, moderate = 200 to 500 mg/dL, moderate to severe = 500 to 1000 mg/dL, and severe > 1000 mg/dL. Because moderate hypertriglyceridemia does increase atherosclerotic cardiovascular disease risk, it is important to determine the underlying etiology to guide appropriate and timely management. This article provides stepwise recommendations on the diagnosis and management of moderate hypertriglyceridemia, based on 3 common scenarios encountered in clinical practice. Initial steps in management include evaluating for secondary contributors, especially diabetes mellitus. Based on patient characteristics, appropriate management decisions include lifestyle adjustments aimed at weight loss and decreasing alcohol consumption and use of statin and nonstatin therapies.

Antiretroviral Therapy-Induced Dysregulation of Gene Expression and Lipid Metabolism in HIV+ Patients: Beneficial Role of Antioxidant Phytochemicals

Human immunodeficiency virus (HIV) infection has continued to be the subject of study since its discovery nearly 40 years ago. Significant advances in research and intake of antiretroviral therapy (ART) have slowed the progression and appearance of the disease symptoms and the incidence of concomitant diseases, which are the leading cause of death in HIV+ persons. However, the prolongation of ART is closely related to chronic degenerative diseases and pathologies caused by oxidative stress (OS) and alterations in lipid metabolism (increased cholesterol levels), both of which are conditions of ART. Therefore, recent research focuses on using natural therapies to diminish the effects of ART and HIV infection: regulating lipid metabolism and reducing OS status. The present review summarizes current information on OS and cholesterol metabolism in HIV+ persons and how the consumption of certain phytochemicals can modulate these. For this purpose, MEDLINE and SCOPUS databases were consulted to identify publications investigating HIV disease and natural therapies and their associated effects.

Dunnigan lipodystrophy syndrome: French National Diagnosis and Care Protocol (PNDS; Protocole National de Diagnostic et de Soins)

Dunnigan syndrome, or Familial Partial Lipodystrophy type 2 (FPLD2; ORPHA 2348), is a rare autosomal dominant disorder due to pathogenic variants of the LMNA gene. The objective of the French National Diagnosis and Care Protocol (PNDS; Protocole National de Diagnostic et de Soins), is to provide health professionals with a guide to optimal management and care of patients with FPLD2, based on a critical literature review and multidisciplinary expert consensus. The PNDS, written by members of the French National Reference Center for Rare Diseases of Insulin Secretion and Insulin Sensitivity (PRISIS), is available on the French Health Authority website (in French). Dunnigan syndrome is characterized by a partial atrophy of the subcutaneous adipose tissue and by an insulin resistance syndrome, associated with a risk of metabolic, cardiovascular and muscular complications. Its prevalence, assessed at 1/100.000 in Europe, is probably considerably underestimated. Thorough clinical examination is key to diagnosis. Biochemical testing frequently shows hyperinsulinemia, abnormal glucose tolerance and hypertriglyceridemia. Elevated hepatic transaminases (hepatic steatosis) and creatine phosphokinase, and hyperandrogenism in women, are common. Molecular analysis of the LMNA gene confirms diagnosis and allows for family investigations. Regular screening and multidisciplinary monitoring of the associated complications are necessary. Diabetes frequently develops from puberty onwards. Hypertriglyceridemia may lead to acute pancreatitis. Early atherosclerosis and cardiomyopathy should be monitored. In women, polycystic ovary syndrome is common. Overall, the management of patients with Dunnigan syndrome requires the collaboration of several health care providers. The attending physician, in conjunction with the national care network, will ensure that the patient receives optimal care through regular follow-up and screening. The various elements of this PNDS are described to provide such a support.

Adipocyte-Specific CDK7 Ablation Leads to Progressive Loss of Adipose Tissue and Metabolic Dysfunction

Adipose tissue regulates whole-body energy homeostasis. Both lipodystrophy and obesity, the extreme and opposite aspects of adipose tissue dysfunction, result in metabolic disorders: insulin resistance and hepatic steatosis. Cyclin-dependent kinases (CDKs) have been reported to be involved in adipose tissue development and functions. Using adipose tissue-specific knockout mice, here we demonstrate that the deletion of CDK7 in adipose tissue results in progressive lipodystrophy, insulin resistance, impaired adipokine secretion and down-regulation of fat-specific genes, which are aggravated on high-fat diet and during aging. Our studies suggest that CDK7 is a key regulatory component of adipose tissue maintenance and systemic energy homeostasis.

Serpina3c regulates adipose differentiation via the Wnt/β-catenin-PPARγ pathway

OBJECTIVE

The Serpin protein family plays an important role in regulating the functioning of the adipose tissue. This study aimed to study the underlying mechanisms of Serpina3c in regulating adipogenesis.

METHODS

We developed a Serpina3c knockout (Serpina3c^-/-) mouse model and Serpina3c knockdown and overexpression 3 T3-L1 preadipocyte models to evaluate the role of Serpina3c in adipose differentiation. Mice were fed on ND for 12-month or HFD for one month. The body weight, glucose tolerance, and insulin tolerance of the mice were subsequently measured. Lipid depositions and adipose tissue morphology were then detected using Oil red O staining and HE staining. qRT-PCR and Western blot were used to detect the expression of adipose differentiation transcription factors.

RESULTS

Serpina3c^-/- mice exhibited lower body weight and white adipose tissue (WAT) weight than WT mice after 12 months of being fed on ND. Additionally, there was an increase in serum and hepatic triglyceride (TG) levels in Serpina3c^-/- mice, without changes in glucose metabolism. Wnt/β-catenin was upregulated while PPARγ expression was decreased in knockout mice WAT. Impaired adipocyte differentiation caused by Serpina3c knockdown was reversed by IWR-1 and kallistatin through an increase in PPARγ expression. Serpina3c^-/- mice fed on HFD for one month had a lower body weight and WAT than WT, accompanied by increased lipid depositions in the liver and muscles and severe insulin resistance.

CONCLUSION

Serpina3c promotes adipogenesis and maintains normal fat function by inhibiting the Wnt/β-catenin pathway.

Polycystic Ovary Syndrome: An Evolutionary Adaptation to Lifestyle and the Environment

Polycystic ovary syndrome (PCOS) is increasingly recognized as a complex metabolic disorder that manifests in genetically susceptible women following a range of negative exposures to nutritional and environmental factors related to contemporary lifestyle. The hypothesis that PCOS phenotypes are derived from a mismatch between ancient genetic survival mechanisms and modern lifestyle practices is supported by a diversity of research findings. The proposed evolutionary model of the pathogenesis of PCOS incorporates evidence related to evolutionary theory, genetic studies, in utero developmental epigenetic programming, transgenerational inheritance, metabolic features including insulin resistance, obesity and the apparent paradox of lean phenotypes, reproductive effects and subfertility, the impact of the microbiome and dysbiosis, endocrine-disrupting chemical exposure, and the influence of lifestyle factors such as poor-quality diet and physical inactivity. Based on these premises, the diverse lines of research are synthesized into a composite evolutionary model of the pathogenesis of PCOS. It is hoped that this model will assist clinicians and patients to understand the importance of lifestyle interventions in the prevention and management of PCOS and provide a conceptual framework for future research. It is appreciated that this theory represents a synthesis of the current evidence and that it is expected to evolve and change over time.

Manual plasma exchange to treat an accidental overdose of intravenous lipid emulsion in a dog with baclofen toxicosis

CASE DESCRIPTION

An approximately 2-year-old sexually intact male German Shorthair Pointer was presented for treatment of baclofen toxicosis.

CLINICAL FINDINGS

The dog had signs of severe baclofen toxicosis (no gag reflex, intermittent vocalization, and stupor) and received intravenous lipid emulsion (142 mL/kg) as a constant rate infusion over 11 hours. Severe hypertriglyceridemia (29,221 mg/dL; reference interval, 19 to 133 mg/dL) developed, followed by cardiovascular depression (poor peripheral perfusion, hyperlactatemia, and hypertension), severe hypoglycemia (26 mg/dL), acute kidney injury (serum creatinine, 3.6 mg/dL), intravascular hemolysis, and coagulopathy (hypocoagulable thromboelastogram and marked bilateral epistaxis).

TREATMENT AND OUTCOME

Therapeutic plasma exchange was performed in 4 stages to treat the hypertriglyceridemia. For each stage, an approximately 500-mL aliquot of blood (22 mL/kg) was removed and centrifuged, and the patient’s RBCs and allogenic fresh-frozen plasma were returned to the dog. Approximately 1.2 times the dog’s plasma volume was exchanged, reducing the serum triglyceride concentration to 1,349 mg/dL and improving the dog’s cardiovascular function and coagulation. Hours after the procedure was completed, the dog regurgitated and developed acute respiratory distress as a result of presumptive aspiration pneumonia, and the owner elected to have the dog euthanized.

CLINICAL RELEVANCE

Veterinarians should be aware of possible complications associated with administration of intravenous lipid emulsion, and veterinary-specific guidelines for the maximum dose of intravenous lipid emulsion should be developed to help prevent adverse effects. TPE appears to be an effective method for treating iatrogenic hypertriglyceridemia in dogs.

Treatment Options for Lipodystrophy in Children

Lipodystrophy includes a heterogeneous group of rare diseases characterized by different amounts of adipose tissue loss and several metabolic complications, including hypertriglyceridemia, steatohepatitis and particularly insulin resistance, that may lead to severe morbidity and, sometimes, mortality. Therefore, therapy for lipodystrophy primarily consists of a conventional approach that involves standard treatments of metabolic abnormalities. Given the evidence of leptin deficiency in lipodystrophy syndromes, leptin replacement therapy has been considered as a treatment option. Long-term studies on the use of therapy with a methionylated analog of human leptin, metreleptin, first on animals and subsequently on human patients, demonstrated enormous improvements of patients' clinical features and metabolic conditions. Recently, metreleptin was approved by Food and Drug Administration (FDA) for the treatment of generalized lipodystrophy and by European Medicines Agency (EMA) for the treatment of both generalized and partial lipodystrophy. However, further research is being conducted for new and different therapeutic agents, especially helpful for the treatment of patients with partial lipodystrophy, as some of them do not have access to metreleptin therapy or show poor response.

Circulating Levels of MiRNAs From 320 Family in Subjects With Lipodystrophy: Disclosing Novel Signatures of the Disease

Lipodystrophy (LD) indicates a group of rare disorders, with generalized or partial loss of white adipose tissue (WAT) often associated with metabolic derangements. Heterogeneity/wide spectrum of the disease and lack of biomarkers make diagnosis often difficult. MicroRNAs are important to maintain a correct WAT function and WAT is a source of circulating miRNAs (cmiRs). miRNAs from 320 family were previously detected in the WAT and variably associated to the metabolic syndrome. Our aim was then to investigate if LD can result in altered abundance of cmiRs-320. We collected samples from a cohort of LD subjects of various subtypes and from age matched controls. Use of quantitative PCR determined that cmiRs- 320a-3p, 320b, 320c, 320e are upregulated, while 320d is downregulated in LD. CmiRs-320 power as classifiers was more powerful in the most extreme and defined forms of LD, including the generalized and the Dunnigan subtypes. cmiR-320a-3p showed significant inverse relationships with plasma leptin (P < 0.0001), typically low in LD. The hepatic enzymes gamma-glutamyl transferase (GGT), aspartate aminotransferase (AST), alanine aminotransferase (ALT) and the marker of inflammation C-reactive protein (CRP) were inversely related to cmiR 320d (P < 0.05, for CRP and GGT; P < 0.01, for AST and ALT). Gene ontology analysis revealed cell-cell adhesion as a process regulated by 320 miRNAs targets, thus disclosing a novel route to investigate origin of WAT loss/dysfunction. In conclusion, cmiRs-320 constitute novel biomarkers of LD, abundance of miR320a-3p is inversely associated to indicators related to WAT function, while downregulation of cmiR-320d predicts an altered hepatic profile and higher inflammation.

Suggestive Evidence for an Antidepressant Effect of Metreleptin Treatment in Patients with Lipodystrophy

INTRODUCTION

Lipodystrophy (LD) syndromes are rare heterogeneous disorders characterized by reduction or absence of subcutaneous fat, low or nondetectable leptin concentrations in blood and impaired hunger/satiety regulation. Metreleptin treatment reverses metabolic complications and improves eating behavior in LD. Because depression in anorexia nervosa (AN), which is also characterized by hypoleptinemia, improves substantially upon treatment with metreleptin, we hypothesized that metreleptin substitution may be associated with an antidepressant effect in patients with LD, too.

METHODS

In this ancillary study, 10 adult patients with LD were treated with metreleptin. To assess depressive symptoms, the self-rating questionnaire Beck's Depression Inventory (BDI) was filled in at preestablished time points prior (T1) and after initiation of metreleptin (T2: 1 week; T3: 4 weeks; T4: 12 weeks) dosing. The differences between time points were tested with nonparametric Friedman's analysis of variance. Sensitivity analyses were performed upon exclusion of the BDI items addressing appetite and weight changes.

RESULTS

According to their BDI scores, 4 patients had mild depression and 2 had moderate depression at baseline. Friedman's test revealed significant differences in BDI scores between the four time points. Post hoc analyses revealed that the difference between T1 and T3 was significant upon Bonferroni correction (p = 0.034, effect size r = 0.88). The sensitivity analyses upon exclusion of the appetite and weight change items again revealed a significant Friedman's test and significant Bonferroni corrected differences in the revised BDI scores between T1 versus T2 (p = 0.002, r = 0.99) and T1 versus T3 (p = 0.007, r = 0.79).

DISCUSSION/CONCLUSION

Our study for the first time revealed suggestive evidence for an antidepressant effect of metreleptin in patients with LD. Metreleptin caused a rapid drop in depression scores within 1 week of treatment. A reduction of the depression score was also observed in 2 of the 3 LD patients whose BDI scores were in the normal range before start of the treatment. The reduction in total scores of BDI was still apparent after 3 months (T4) of dosing. This observation matches findings obtained in clinical case studies of AN patients, in whom depression scores also dropped during the first week of metreleptin treatment. It needs to be noted that by the nature of this observational study without a placebo group, nonspecific treatment expectation affecting mood cannot fully be ruled out.

Adipocyte Biology from the Perspective of In Vivo Research: Review of Key Transcription Factors

Obesity and type 2 diabetes are both significant contributors to the contemporary pandemic of non-communicable diseases. Both disorders are interconnected and associated with the disruption of normal homeostasis in adipose tissue. Consequently, exploring adipose tissue differentiation and homeostasis is important for the treatment and prevention of metabolic disorders. The aim of this work is to review the consecutive steps in the postnatal development of adipocytes, with a special emphasis on in vivo studies. We gave particular attention to well-known transcription factors that had been thoroughly described in vitro, and showed that the in vivo research of adipogenic differentiation can lead to surprising findings.

Barraquer-Simons syndrome in systemic lupus erythematosus: A case report

Barraquer-Simons syndrome is a rare entity characterized by progressive loss of subcutaneous tissue in the face and/or upper half of the body and can be associated with autoimmune conditions such as systemic lupus erythematosus. Close long-term follow-up is required to identify metabolic disturbances, potentially life-threatening renal problems, and other associated diseases.

Familial partial lipodystrophy syndromes

Lipodystrophies are a heterogeneous group of rare conditions characterised by the loss of adipose tissue. The most common forms are the familial partial lipodystrophy (FPLD) syndromes, which include a set of disorders, usually autosomal dominant, due to different pathogenetic mechanisms leading to improper fat distribution (loss of fat in the limbs and gluteal region and variable regional fat accumulation). Affected patients are prone to suffering serious morbidity via the development of metabolic complications associated to insulin resistance and an inability to properly store lipids. Although no well-defined diagnostic criteria have been established for lipodystrophy, there are certain clues related to medical history, physical examination and body composition evaluation that may suggest FPLD prior to confirmatory genetic analysis. Its treatment must be fundamentally oriented towards the control of the metabolic abnormalities. In this sense, metreleptin therapy, the newer classes of hypoglycaemic agents and other investigational drugs are showing promising results. This review aims to summarise the current knowledge of FPLD syndromes and to describe their clinical and molecular picture, diagnostic approaches and recent treatment modalities.

Autoimmunity in lipodystrophy syndromes

Lipodystrophy syndromes are rare, heterogeneous disorders characterized by the complete or partial deficiency of adipose tissue and are classified according to the extent of fat loss in generalized or partial subtypes, or based on the pathogenic mechanisms in genetic or acquired. While in most cases of congenital forms of lipodystrophy a genetic alteration can be identified, the pathogenic mechanisms responsible for the acquired diseases are not fully clarified. Based on the evidence of a positive association between most acquired lipodystrophies and autoimmune disorders including immune mediated alterations in the adipose tissue of patients affected by acquired lipodystrophy, a reaction against white adipose tissue antigens is postulated. Recent acquisitions have shed new light on the possible pathogenic mechanisms and identified novel forms of acquired lipodystrophy which are possibly immune-mediated. The aim of this review is to give an update on acquired lipodystrophies describing pathogenic mechanisms involved and the relationships between acquired lipodystrophies and other autoimmune disorders. Larger studies based on international disease registries are needed to collect accurate information on the prevalence, risk factors, genetic predisposition, natural history, disease markers and treatment efficacy of these ultrarare disorders.