Pharmacokinetics and pharmacodynamics of mibavademab (a leptin receptor agonist): Results from a first-in-human phase I study

Mibavademab (previously known as REGN4461), a fully human monoclonal antibody, is being investigated for the treatment of conditions associated with leptin deficiency. Here, we report pharmacokinetics (PKs), pharmacodynamics, and immunogenicity from a phase I study in healthy participants (NCT03530514). In part A, lean or overweight healthy participants were randomized to single-ascending-dose cohorts of 0.3, 1.0, 3.0, 10, and 30 mg/kg intravenous (i.v.), or 300 and 600 mg subcutaneous doses of mibavademab or placebo. In part B, overweight or obese participants were randomized to receive multiple doses of mibavademab (15 mg/kg i.v. loading dose and 10 mg/kg i.v. at weeks 3, 6, and 9) or placebo, stratified by body mass index and baseline leptin levels: low leptin (<5 ng/mL) or relatively low leptin (5-8 ng/mL in men and 5-24 ng/mL in women). Fifty-six and 55 participants completed the single-ascending-dose and multiple-dose parts, respectively. In the single-ascending-dose cohorts, mibavademab PKs were nonlinear with target-mediated elimination, greater than dose-proportional increases in exposure, and there were no dose-dependent differences in total soluble leptin receptor (sLEPR) levels in serum over time. Following multiple-dose administration of mibavademab in participants with leptin <8 ng/mL, lower mean mibavademab concentrations, higher mean total sLEPR concentrations, and larger mean decreases in body weight than in the relatively low leptin cohorts were observed. Baseline leptin was correlated with mibavademab PKs and pharmacodynamics. No treatment-emergent anti-mibavademab antibodies were observed in any mibavademab-treated participant. Results from this study collectively inform further development of mibavademab to treat conditions associated with leptin deficiency.

Leptin Increase During Dexamethasone and Its Association With Hunger and Fat in Pediatric Acute Lymphoblastic Leukemia

CONTEXT

During treatment, children with acute lymphoblastic leukemia (ALL) receive high doses dexamethasone, which induce acute side effects.

OBJECTIVE

To determine the influence of a 5-day dexamethasone course on changes in leptin, fat mass, BMI, hunger, sleep, and fatigue and to explore associations between these changes.

METHODS

Pediatric ALL patients were included during maintenance treatment. Data were collected before (T1) and after (T2) a 5-day dexamethasone course (6 mg/m2/day). At both time points, BMI, fat mass (bioelectrical impedance analysis), and leptin were assessed, as well as parent-reported questionnaires regarding hunger, fatigue, and sleep problems. Changes between T1 and T2 were assessed using paired tests. Correlation coefficients were calculated to assess associations between these changes (Delta scores: T2-T1). Univariable regression models were estimated to study associations between covariates and elevated leptin.

RESULTS

We included 105 children, with median age 5.4 years (range, 3.0-18.8). Leptin and fat mass, as well as hunger scores, fatigue, and sleep deteriorated after 5 days of dexamethasone (P < .001), in contrast to BMI (P = .12). No correlations between delta leptin and delta fat mass, BMI, hunger, fatigue, or sleep were found. Elevated leptin on T1 was associated with older age (odds ratio [OR] 1.51; 95% CI, 1.28-1.77), higher fat mass (OR 1.19; 95% CI, 1.07-1.33), and earlier maintenance week (OR 0.96; 95% CI, 0.92-0.99).

CONCLUSION

Five days of high-dose dexamethasone treatment led to direct and significant changes in leptin, hunger scores, and fat mass. Since children with ALL are at increased risk for metabolic adverse events, understanding underlying mechanisms is important, and a dexamethasone-induced state of acute leptin resistance might play a role.

The corrective role of superparamagnetic iron oxide nanoparticles for the genes controlling hypothalamus-pituitary-testis-axis in male obesity-associated secondary hypogonadism

Background

Obesity is one of the most prevalent and perilous health affairs. Male obesity-associated secondary hypogonadism (MOSH) is one of many of its complexities, which is mounting in parallel with the aggravation of obesity. Magnetic nanoparticles seem to be an advanced favorable trend in multiple biomedical fields.

Aim

In this study, we explore the therapeutic effects of superparamagnetic iron oxide nanoparticles (SPIONs) coated with carboxymethyl cellulose (CMC) on an obese male rat model with MOSH syndrome, comparing their impacts with a well-known anti-obesity medication (Orlistat).

Methods

42 male albino rats split into 7 equal groups: 1-negative control: nonobese, untreated; 35 rats fed the high fat-high fructose (HFHF) diet for a period of 12 weeks. Obese rats splitted into 6 equal groups; 2-positive control: obese untreated; 3-obese given Orlistat (30 mg/kg); 4-obese given CMC-SPIONs (25 mgFe/kg); 5-obese given CMC-SPIONs (50 mgFe/kg); 6-obese given CMC-SPIONs(25 mgFe/kg) + Orlistat (30 mg/kg), 7-obese given CMC-SPIONs (50 mgFe/kg) + Orlistat (30 mg/kg); all treatments given orally for 4 weeks. During sacrifice, blood serum and sectioned hypothalamic, pituitary, testicular, and adipose tissues were collected for biochemical and biomolecular assessments.

Results

The HFHF diet for 12 weeks resulted in a significant upsurge in body weight, body mass index, serum fasting glucose, insulin resistance, TAG, total cholesterol, and LDL-c; HDL-c was dropped. Serum FSH, LH, and testosterone values declined. A significant disorder in expression levels of genes regulating the hypothalamic-pituitary-testicular-axis pathway. Hypothalamic GnRH, Kisspeptin-1, Kisspeptin-r1, and Adipo-R1 values declined. GnIH and Leptin-R1 values raised up. Pituitary GnRH-R values declined. Testicular tissue STAR, HSD17B3, and CYP19A1 values declined. Adipose tissue adiponectin declined, while leptin raised up. CMC-SPIONs 25-50 mg could modulate the deranged biochemical parameters and correct the deranged expression levels of all previous genes. Co-treatments revealed highly synergistic effects on all parameters. Overall, CMC-SPIONs have significant efficiency whether alone or with Orlisat in limiting obesity and consequence subfertility.

Conclusion

CMC-SPIONs act as an incoming promising contender for obesity and MOSH disorders management, and need more studies on their mechanisms.

Weight Loss and Vitamin D Improve Hyporesponsiveness to Corticosteroids in Obese Asthma

BACKGROUND AND OBJECTIVES

Obesity negatively impacts on the response of asthma patients to inhaled corticosteroids. The mechanisms underlying this impact are unknown. Objective: To demonstrate that the poor response to inhaled corticosteroids in obese asthma patients is associated with impaired anti-inflammatory activity of corticosteroids and vitamin D deficiency, both of which are improved by weight loss.

METHODS

The study population comprised 23 obese asthma patients (OA) (18 females; median (IQR) age 56 [51-59] years), 14 nonobese asthma patients (NOA) (11 females; 53 [43-60] years), 15 obese patients (OP) (13 females; 47 [45-60] years), and 19 healthy controls (HC) (14 females; 43 [34-56] years). Ten OA and 11 OP were evaluated at baseline (V1) and 6 months after bariatric surgery (V2). Corticosteroid response was measured using dexamethasone-induced inhibition of peripheral blood mononuclear cell (PBMC) proliferation. Lung function and serum levels of leptin, adiponectin, and vitamin D were measured at V1 and V2.

RESULTS

We found a reduced response to dexamethasone in PBMCs of OP and OA with respect to NOA and HC; this inversely correlated with the adiponectin/leptin ratio and vitamin D levels. Bariatric surgery improved corticosteroid responses in OP and OA and normalized the adiponectin/leptin ratio and vitamin D levels. Exposure of PBMCs to vitamin D potentiated the antiproliferative effects of corticosteroids. Dexamethasone and vitamin D induced similar MKP1 expression in OP and OA.

CONCLUSION

The efficacy of weight loss to improve symptoms and lung function in OA may be due, at least in part, to the recovered anti-inflammatory effects of corticosteroids. Vitamin D deficiency may contribute to corticosteroid hyporesponsiveness in OA.

Preclinical, randomized phase 1, and compassionate use evaluation of REGN4461, a leptin receptor agonist antibody for leptin deficiency

Deficiency in the adipose-derived hormone leptin or leptin receptor signaling causes class 3 obesity in individuals with genetic loss-of-function mutations in leptin or its receptor LEPR and metabolic and liver disease in individuals with hypoleptinemia secondary to lipoatrophy such as in individuals with generalized lipodystrophy. Therapies that restore leptin-LEPR signaling may resolve these metabolic sequelae. We developed a fully human monoclonal antibody (mAb), REGN4461 (mibavademab), that activates the human LEPR in the absence or presence of leptin. In obese leptin knockout mice, REGN4461 normalized body weight, food intake, blood glucose, and insulin sensitivity. In a mouse model of generalized lipodystrophy, REGN4461 alleviated hyperphagia, hyperglycemia, insulin resistance, dyslipidemia, and hepatic steatosis. In a phase 1, randomized, double-blind, placebo-controlled two-part study, REGN4461 was well tolerated with an acceptable safety profile. Treatment of individuals with overweight or obesity with REGN4461 decreased body weight over 12 weeks in those with low circulating leptin concentrations (<8 ng/ml) but had no effect on body weight in individuals with higher baseline leptin. Furthermore, compassionate-use treatment of a single patient with atypical partial lipodystrophy and a history of undetectable leptin concentrations associated with neutralizing antibodies to metreleptin was associated with noteable improvements in circulating triglycerides and hepatic steatosis. Collectively, these translational data unveil an agonist LEPR mAb that may provide clinical benefit in disorders associated with relatively low leptin concentrations.

Effects of Moringa Oleifera Leaf Extract Plus Rosiglitazone on Serum Leptin and Glucose and Lipid Metabolism in Type 2 Diabetic Rats

Objective

To investigate the effects of Moringa Oleifera Leaf Extract (MOLE) plus rosiglitazone (RSG) on glucose and lipid metabolism, serum leptin, and the Akt/GSK3β/β-Catenin signaling pathway in type 2 diabetic (T2D) rats.

Methods

Sixty male Sprague-Dawley (SD) rats were randomly divided into six groups: the normal group, the model group, the RSG group, the low- and high-dose MOLE group, and the MOLE+RSG group. The normal group was fed a standard rat diet, while the other groups were given a single intraperitoneal injection of low-dose streptozomycin (STZ) (35 mg/kg) and fed a high-sugar and high-fat diet. After 8 weeks, the treatment outcomes were evaluated by measuring key parameters of blood glucose and lipid metabolism and the protein kinase B (AKT) / Glycogen synthase kinase 3beta (GSK3β) /β-Catenin signaling pathway in the T2D rats.

Results

Compared with the normal group, the model group showed significantly increased levels of blood glucose, blood lipids, serum leptin, free fatty acid (FFA), and tumor necrosis factor-α (TNF-α). Compared with the model group, the RSG, low-dose MOLE, and high-dose MOLE groups displayed effective control of blood glucose, blood lipids, serum leptin, FFA, and TNF-α. The MOLE+RSG group surpassed the RSG group in regulating glucose, lipid metabolism, and serum leptin levels in T2D rats. In addition, the MOLE+RSG group also had superiority over the RSG group in activating the AKT/GSK3β/β-Catenin pathway.

Conclusion

MOLE plus RSG can effectively reduce blood glucose and blood lipids in T2DM rats.

The Narrative of a Patient with Leptin Receptor Deficiency: Personalized Medicine for a Rare Genetic Obesity Disorder

Leptin receptor (LEPR) deficiency is a rare genetic disorder that affects the body's ability to regulate appetite and weight. For patients and their families, the disorder seriously disrupts daily life; however, little is published about this impact. We here report the experiences of a 10.5-year-old girl with leptin receptor deficiency and her family. The diagnosis of this rare genetic obesity had a deep impact on the life of the child and her family. It led to a better understanding of the cause of the impaired appetite regulation and early-onset obesity with subsequently less judgement by others and improved cooperation of their social network and school on maintaining a healthy lifestyle for this girl. A strict eating regimen and lifestyle measures resulted in the first year after diagnosis in a significantly decreased body mass index (BMI), followed by BMI stabilization, still categorized as obesity class three. However, the troublesome challenge of how to manage the disruptive behaviour due to hyperphagia remained. Eventually, due to treatment with targeted pharmacotherapy, i.e., melanocortin-4 receptor agonists, her BMI continued to decrease due to resolving hyperphagia. The daily routine of the family and the atmosphere at home positively changed as they were no longer dominated by the food-focused behaviour of the child and the adherence to the strict eating regimen. This case report demonstrates the importance and impact of a rare genetic obesity disorder diagnosis in a family. Additionally, it highlights the value of genetic testing in patients with a high suspicion of a genetic obesity disorder as it can eventually lead to personalized treatment, such as guidance by specialized healthcare professionals and educated caregivers or targeted pharmacotherapy.

Alcohol self-administration and nicotine withdrawal alter biomarkers of stress and inflammation and prefrontal cortex changes in Gβ subunits

Background: Although alcohol and nicotine are often used together, the biological consequences of these substances are not well understood. Identifying shared targets will inform cessation pharmacotherapies and provide a deeper understanding of how co-use of alcohol and nicotine impacts health, including biomarkers of stress and inflammation.Objective: We examined the effects of nicotine exposure and withdrawal on alcohol self-administration (SA), stress and inflammatory biomarkers, and a G-protein coupled receptor subunit (Gβ) in brain areas associated with drug use.Methods: Male rats were trained to SA alcohol and then received a nicotine pump (n = 7-8 per group). We assessed alcohol intake for 12 days during nicotine exposure and then following pump removal to elicit withdrawal. After the behavioral studies, we assessed plasma leptin, corticosterone, and interleukin-1β (IL-1β), and Gβ protein expression in the amygdala, nucleus accumbens (NAc), and prefrontal cortex (PFC).Results: Nicotine exposure or withdrawal did not alter alcohol intake (p > .05). Alcohol and nicotine withdrawal elevated corticosterone levels (p = .015) and decreased Gβ levels in the PFC (p = .004). In the absence of nicotine, alcohol SA suppressed IL-1β levels (p = .039). Chronic exposure to nicotine or withdrawal during alcohol SA did not alter leptin levels or Gβ expression in the amygdala or NAc (p's > .05).Conclusions: The combination of alcohol SA and nicotine withdrawal produced a persistent increase in stress biomarkers and a suppression in Gβ expression in the PFC, providing an important first step toward understanding the common biological mechanisms of alcohol/nicotine misuse.

Mechanistic Links Between Obesity and Airway Pathobiology Inform Therapies for Obesity-Related Asthma

Obesity-related asthma is associated with a high disease burden and a poor response to existent asthma therapies, suggesting that it is a distinct asthma phenotype. The proposed mechanisms that contribute to obesity-related asthma include the effects of the mechanical load of obesity, adipokine perturbations, and immune dysregulation. Each of these influences airway smooth muscle function. Mechanical fat load alters airway smooth muscle stretch affecting airway wall geometry, airway smooth muscle contractility, and agonist delivery; weight loss strategies, including medically induced weight loss, counter these effects. Among the metabolic disturbances, insulin resistance and free fatty acid receptor activation influence distinct signaling pathways in the airway smooth muscle downstream of both the M2 muscarinic receptor and the β2 adrenergic receptor, such as phospholipase C and the extracellular signal-regulated kinase signaling cascade. Medications that decrease insulin resistance and dyslipidemia are associated with a lower asthma disease burden. Leptin resistance is best understood to modulate muscarinic receptors via the neural pathways but there are no specific therapies for leptin resistance. From the immune perspective, monocytes and T helper cells are involved in systemic pro-inflammatory profiles driven by obesity, notably associated with elevated levels of interleukin-6. Clinical trials on tocilizumab, an anti-interleukin antibody, are ongoing for obesity-related asthma. This armamentarium of therapies is distinct from standard asthma medications, and once investigated for its efficacy and safety among children, will serve as a novel therapeutic intervention for pediatric obesity-related asthma. Irrespective of the directionality of the association between asthma and obesity, airway-specific mechanistic studies are needed to identify additional novel therapeutic targets for obesity-related asthma.

Rapid Emergence of Appetite and Hunger Resulting in Weight Gain and Improvement of Eating Disorder Symptomatology during and after Short-Term Off-Label Metreleptin Treatment of a Patient with Anorexia Nervosa

Off-label treatment of a 15-year-old female patient with anorexia nervosa (AN) with human recombinant leptin (metreleptin) for nine days was associated with self-reported increments of appetite and hunger resulting in rapid weight gain and substantial improvement of eating disorder cognitions and of depression. The results further substantiate the effects of metreleptin on both AN and depression. We contrast these results with the widespread view that leptin is an anorexigenic hormone. Randomized controlled trials are warranted to confirm the described effects.

Effect of Lactobacillus plantarum LMT1-48 on Body Fat in Overweight Subjects: A Randomized, Double-Blind, Placebo-Controlled Trial

BACKGROUND

We investigated whether Lactobacillus plantarum strain LMT1-48, isolated from Korean fermented foods and newborn feces, is a suitable probiotic supplement to treat overweight subjects.

METHODS

In this randomized, double-blind, placebo-controlled clinical trial, 100 volunteers with a body mass index of 25 to 30 kg/m2 were assigned randomly (1:1) to receive 2×1010 colony forming units of LMT1-48 or to a placebo treatment group. Body composition was measured by dual-energy X-ray absorptiometry, and abdominal visceral fat area (VFA) and subcutaneous fat area were measured by computed tomography scanning. Changes in body fat, VFA, anthropometric parameters, and biomarkers were compared between the two treatment groups (ClinicalTrials.gov number: NCT03759743).

RESULTS

After 12 weeks of treatment, the body weight decreased significantly from 76.6±9.4 to 75.7±9.2 kg in the LMT1-48 group but did not change in the placebo group (P=0.022 between groups). A similar pattern was found in abdominal VFA between the two groups (P=0.041). Serum insulin levels, the corresponding homeostasis model assessment of insulin resistance, and leptin levels decreased in the LMT1-48 group but increased in the placebo group (all P<0.05). Decrease in body weight and body mass index by treatment with LMT1-48 was correlated with increase in Lactobacillus levels significantly. LMT1-48 also increased Oscillibacter levels significantly, which were negatively correlated with triglyceride and alanine transaminase levels.

CONCLUSION

Administration of LMT1-48 decreased body weight, abdominal VFA, insulin resistance, and leptin levels in these subjects with overweight, suggesting its anti-obesogenic therapeutic potential.

Achievements, prospects and challenges in precision care for monogenic insulin-deficient and insulin-resistant diabetes

Integration of genomic and other data has begun to stratify type 2 diabetes in prognostically meaningful ways, but this has yet to impact on mainstream diabetes practice. The subgroup of diabetes caused by single gene defects thus provides the best example to date of the vision of 'precision diabetes'. Monogenic diabetes may be divided into primary pancreatic beta cell failure, and primary insulin resistance. In both groups, clear examples of genotype-selective responses to therapy have been advanced. The benign trajectory of diabetes due to pathogenic GCK mutations, and the sulfonylurea-hyperresponsiveness conferred by activating KCNJ11 or ABCC8 mutations, or loss-of-function HNF1A or HNF4A mutations, often decisively guide clinical management. In monogenic insulin-resistant diabetes, subcutaneous leptin therapy is beneficial in some severe lipodystrophy. Increasing evidence also supports use of 'obesity therapies' in lipodystrophic people even without obesity. In beta cell diabetes the main challenge is now implementation of the precision diabetes vision at scale. In monogenic insulin-resistant diabetes genotype-specific benefits are proven in far fewer patients to date, although further genotype-targeted therapies are being evaluated. The conceptual paradigm established by the insulin-resistant subgroup with 'adipose failure' may have a wider influence on precision therapy for common type 2 diabetes, however. For all forms of monogenic diabetes, population-wide genome sequencing is currently forcing reappraisal of the importance assigned to pathogenic mutations when gene sequencing is uncoupled from prior suspicion of monogenic diabetes.

Therapeutic indications and metabolic effects of metreleptin in patients with lipodystrophy syndromes: Real-life experience from a national reference network

AIM

To describe baseline characteristics and follow-up data in patients with lipodystrophy syndromes treated with metreleptin in a national reference network, in a real-life setting.

PATIENTS AND METHODS

Clinical and metabolic data from patients receiving metreleptin in France were retrospectively collected, at baseline, at 1 year and at the latest follow-up during treatment.

RESULTS

Forty-seven patients with lipodystrophy including generalized lipodystrophy (GLD; n = 28) and partial lipodystrophy (PLD; n = 19) received metreleptin over the last decade. At baseline, the median (interquartile range [IQR]) patient age was 29.3 (16.6-47.6) years, body mass index was 23.8 (21.2-25.7) kg/m² and serum leptin was 3.2 (1.0-4.9) ng/mL, 94% of patients had diabetes (66% insulin-treated), 53% had hypertension and 87% had dyslipidaemia. Metreleptin therapy, administered for a median (IQR) of 31.7 (14.2-76.0) months, was ongoing in 77% of patients at the latest follow-up. In patients with GLD, glycated haemoglobin (HbA1c) and fasting triglyceride levels significantly decreased from baseline to 1 year of metreleptin treatment, from 8.4 (6.5-9.9)% [68 (48-85) mmol/mol] to 6.8 (5.6-7.4)% [51(38-57) mmol/mol], and 3.6 (1.7-8.5) mmol/L to 2.2 (1.1-3.7) mmol/L, respectively (P < 0.001), with sustained efficacy thereafter. In patients with PLD, HbA1c was not significantly modified (7.7 [7.1-9.1]% [61 (54-76) mmol/mol] at baseline vs. 7.7 [7.4-9.5]% [61(57-80) mmol/mol] at 1 year), and the decrease in fasting triglycerides (from 3.3 [1.9-9.9] mmol/L to 2.5 [1.6-5.3] mmol/L; P < 0.01) was not confirmed at the latest assessment (5.2 [2.2-11.3] mmol/L). However, among PLD patients, at 1 year, 61% were responders regarding glucose homeostasis, with lower baseline leptin levels compared to nonresponders, and 61% were responders regarding triglyceridaemia. Liver enzymes significantly decreased only in the GLD group.

CONCLUSIONS

In this real-life setting study, metabolic outcomes are improved by metreleptin therapy in patients with GLD. The therapeutic indication for metreleptin needs to be clarified in patients with PLD.

Adipocytokines and achievement of low disease activity in rheumatoid arthritis

PURPOSE

To determine if adipocytokines are independently associated with the achievement of low disease activity (LDA) over long-term follow-up in a large rheumatoid arthritis (RA) registry.

METHODS

This cohort study evaluated adults with RA from the Veteran's Affairs RA Registry. Adipocytokines (adiponectin, leptin, and fibroblast growth factor [FGF]-21) and inflammatory cytokines were measured as part of a multi-analyte panel on banked serum from enrollment. Covariates were derived from medical record, biorepository, and registry databases. Multivariable Cox proportional hazard models evaluated associations between adipocytokines and rates of 1) DAS28 LDA and remission, 2) individual Boolean remission criteria and 3) initiation of a new bDMARD or tsDMARD.

RESULTS

There were 1,276 participants with a DAS28 >3.2 at enrollment. Of these, 827 achieved LDA and 598 achieved remission over 2,287 and 4,096 person-years, respectively. Patients in the highest quartile of adiponectin had lower rates LDA before and after adjustment [aHR Q4: 0.68 (0.53,0.87) p<0.001]. Those in the highest quartile of leptin and FGF-21 also had lower rates of LDA. Higher quartiles of adipocytokines were also associated with lower rates of achieving a low patient/evaluator global scores and low tender joint counts. Among 1,236 biologic-naïve participants, values above the median for adiponectin [HR: 1.67 (1.23,1.26) p = 0.001] and FGF-21 [HR: 1.27 (1.09,1.47) p = 0.002] were associated with a greater likelihood of initiating a b/tsDMARD.

CONCLUSIONS

Adipocytokines may serve as prognostic biomarkers of a more severe RA disease course. Additional study is needed to determine whether adipocytokines are phenotypic markers or whether they actively promote disease progression.

Approach to the Patient With Lipodystrophy

Lipodystrophy constitutes a spectrum of diseases characterized by a generalized or partial absence of adipose tissue. Underscoring the role of healthy fat in maintenance of metabolic homeostasis, fat deficiency in lipodystrophy typically leads to profound metabolic disturbances including insulin resistance, hypertriglyceridemia, and ectopic fat accumulation. While rare, recent genetic studies indicate that lipodystrophy is more prevalent than has been previously thought, suggesting considerable underdiagnosis in clinical practice. In this article, we provide an overview of the etiology and management of generalized and partial lipodystrophy disorders. We bring together the latest scientific evidence and clinical guidelines and expose key gaps in knowledge. Through improved recognition of the lipodystrophy disorders, patients (and their affected family members) can be appropriately screened for cardiometabolic, noncardiometabolic, and syndromic abnormalities and undergo treatment with targeted interventions. Notably, insights gained through the study of this rare and extreme phenotype can inform our knowledge of more common disorders of adipose tissue overload, including generalized obesity.

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.

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.

Leptin Attenuates Cardiac Hypertrophy in Patients With Generalized Lipodystrophy

CONTEXT

Lipodystrophy syndromes are rare disorders of deficient adipose tissue, low leptin, and severe metabolic disease, affecting all adipose depots (generalized lipodystrophy, GLD) or only some (partial lipodystrophy, PLD). Left ventricular (LV) hypertrophy is common (especially in GLD); mechanisms may include hyperglycemia, dyslipidemia, or hyperinsulinemia.

OBJECTIVE

Determine effects of recombinant leptin (metreleptin) on cardiac structure and function in lipodystrophy.

METHODS

Open-label treatment study of 38 subjects (18 GLD, 20 PLD) at the National Institutes of Health before and after 1 (N = 27), and 3 to 5 years (N = 23) of metreleptin. Outcomes were echocardiograms, blood pressure (BP), triglycerides, A1c, and homeostasis model assessment of insulin resistance.

RESULTS

In GLD, metreleptin lowered triglycerides (median [interquartile range] 740 [403-1239], 138 [88-196], 211 [136-558] mg/dL at baseline, 1 year, 3-5 years, P < .0001), A1c (9.5 ± 3.0, 6.5 ± 1.6, 6.5 ± 1.9%, P < .001), and HOMA-IR (34.1 [15.2-43.5], 8.7 [2.4-16.0], 8.9 [2.1-16.4], P < .001). Only HOMA-IR improved in PLD (P < .01). Systolic BP decreased in GLD but not PLD. Metreleptin improved cardiac parameters in patients with GLD, including reduced posterior wall thickness (9.8 ± 1.7, 9.1 ± 1.3, 8.3 ± 1.7 mm, P < .01), and LV mass (140.7 ± 45.9, 128.7 ± 37.9, 110.9 ± 29.1 g, P < .01), and increased septal e' velocity (8.6 ± 1.7, 10.0 ± 2.1, 10.7 ± 2.4 cm/s, P < .01). Changes remained significant after adjustment for BP. In GLD, multivariate models suggested that reduced posterior wall thickness and LV mass index correlated with reduced triglycerides and increased septal e' velocity correlated with reduced A1c. No changes in echocardiographic parameters were seen in PLD.

CONCLUSION

Metreleptin attenuated cardiac hypertrophy and improved septal e' velocity in GLD, which may be mediated by reduced lipotoxicity and glucose toxicity. The applicability of these findings to leptin-sufficient populations remains to be determined.

Leptin Chronic Effect on Differentiation, Ion Currents and Protein Expression in N1E-115 Neuroblastoma Cells

&lt;b&gt;Background and Objective:&lt;/b&gt; Arcuate nucleus (ARC), a component of appetite-regulatory factors, contains populations of both orexigenic and anorexigenic neurons and one of the fundamental components of its system is leptin. Studies have evidenced the critical neurotrophic role in the development of ARC. To determine such effects on neuron development, N1E-115 neuroblastoma cells were used as an ARC model. &lt;b&gt;Materials and Methods:&lt;/b&gt; N1E-115 neuroblastoma cells were treated with leptin [10 nM] for 24, 48 and 72 hrs. Dimethyl sulfoxide (DMSO) 1.5% was used as a known drug that promotes neurite expression. Cells percentage (%) that developed neurites was evaluated by bright field microscopy. Patch-clamp electrophysiology was used to analyze membrane ion currents, RT-PCR for quantifying changes in mRNA expression of anorexic peptides, proopiomelanocortin (POMC) and cocaine and amphetamine-related transcript (CART), in addition to principal Na&lt;sub&gt;v&lt;/sub&gt;, Ca&lt;sub&gt;v&lt;/sub&gt; ion channel subunits. &lt;b&gt;Results:&lt;/b&gt; N1E-115 cells treated with leptin show neurite expression after 24 hrs of treatment, similar effects were obtained with DMSO. Leptin (time-dependent) increases the inward current in comparison with the control value at 72 hrs. Outward currents were not affected by leptin. Leptin and DMSO increased Na&lt;sup&gt;+&lt;/sup&gt; and Ca&lt;sup&gt;2+&lt;/sup&gt; current without changes in the kinetic properties. Lastly, leptin promotes an increase in mRNA level expression of transcripts to POMC, CART, Na&lt;sub&gt;v&lt;/sub&gt;1.2 and Ca&lt;sub&gt;v&lt;/sub&gt;1.3. &lt;b&gt;Conclusion:&lt;/b&gt; Leptin chronic treatment promotes neurite expression, Up-regulation of Na&lt;sup&gt;+&lt;/sup&gt; and Ca&lt;sup&gt;2+&lt;/sup&gt; ion channels determining neuronal excitability, besides increasing the mRNA level expression of anorexic peptides POMC and CART in neuroblastoma N1E-115.

Effect of Leptin Therapy on Survival in Generalized and Partial Lipodystrophy: A Matched Cohort Analysis

CONTEXT

Data quantifying the impact of metreleptin therapy on survival in non-human immunodeficiency virus (HIV)-related generalized lipodystrophy (GL) and partial lipodystrophy (PL) are unavailable.

OBJECTIVE

This study aimed to estimate the treatment effect of metreleptin on survival in patients with GL and PL.

DESIGN/SETTING/PATIENTS

Demographic and clinical characteristics were used to match metreleptin-treated and metreleptin-naïve patients with GL and PL. Differences in mortality risk were estimated between matched cohorts of metreleptin-treated and metreleptin-naïve patient cohorts using Cox proportional hazard models. Sensitivity analyses assessed the impact of study assumptions and the robustness of results.

OUTCOME MEASURES

This study assessed time-to-mortality and risk of mortality.

RESULTS

The analysis evaluated 103 metreleptin-naïve patients with characteristics matched to 103 metreleptin-treated patients at treatment initiation. Even after matching, some metabolic and organ abnormalities were more prevalent in the metreleptin-treated cohort due to bias toward treating more severely affected patients. A Cox proportional hazards model associated metreleptin therapy with an estimated 65% decrease in mortality risk (hazard ratio [HR] 0.348, 95% confidence interval (CI): 0.134-0.900; P = 0.029) even though the actual number of events were relatively small. Results were robust across a broad range of alternate methodological assumptions. Kaplan-Meier estimates of time-to-mortality for the metreleptin-treated and the matched metreleptin-naïve cohorts were comparable.

CONCLUSIONS

Metreleptin therapy was associated with a reduction in mortality risk in patients with lipodystrophy syndromes despite greater disease severity in treated patients, supporting the view that metreleptin can have a positive disease-modifying impact. Confirmatory studies in additional real-world and clinical datasets are warranted.

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

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