The Effects of Leptin Replacement on Neural Plasticity.

Leptin, an adipokine synthesized and secreted mainly by the adipose tissue, has multiple effects on the regulation of food intake, energy expenditure, and metabolism. Its recently-approved analogue, metreleptin, has been evaluated in clinical trials for the treatment of patients with leptin deficiency due to mutations in the leptin gene, lipodystrophy syndromes, and hypothalamic amenorrhea. In such patients, leptin replacement therapy has led to changes in brain structure and function in intra- and extrahypothalamic areas, including the hippocampus. Furthermore, in one of those patients, improvements in neurocognitive development have been observed. In addition to this evidence linking leptin to neural plasticity and function, observational studies evaluating leptin-sufficient humans have also demonstrated direct correlation between blood leptin levels and brain volume and inverse associations between circulating leptin and risk for the development of dementia. This review summarizes the evidence in the literature on the role of leptin in neural plasticity (in leptin-deficient and in leptin-sufficient individuals) and its effects on synaptic activity, glutamate receptor trafficking, neuronal morphology, neuronal development and survival, and microglial function.

Temporal gene expression in the hippocampus and peripheral organs to endotoxin-induced systemic inflammatory response in caspase-1-deficient mice.

OBJECTIVES: Caspase-1 (casp1), a key protease involved in the systemic inflammatory response syndrome (SIRS), controls the brain expression of a set of eight genes: Nos2 and Ptgs2 (nitric oxide synthase 2 and prostaglandin-endoperoxide synthase 2, two inducible enzymes), Cxcl1 and Cxcl10 (C-X-C motif chemokine ligand 1 and ligand 10), Tgtp and Gbp2 (T cell-specific GTPase 1 and guanylate-binding protein 2, two GTPases), Adamts1 (a disintegrin-like and metallopeptidase with thrombospondin type 1 motif, 1, a metalloprotease) and Il1rn (interleukin-1 receptor antagonist). Our objective was to ascertain whether casp1 also controlled the peripheral expression of these genes and, if so, to compare their central versus peripheral patterns of gene expression in immune and endocrine tissues during SIRS. METHODS: Wild-type (wt) and casp1 knockout (casp1(-/-)) mice were injected with either saline or a high dose of endotoxin/lipopolysaccharide (LPS; 800 µg/mice i.p.). Saline-injected mice were immediately euthanized after injection, whereas LPS-injected mice were sacrificed 6 and 12 h after LPS administration. Hippocampal, splenic and adrenal gene expressions were determined by real-time PCR. RESULTS: Overall, casp1(-/-) mice showed a lower inflammatory response than wt mice. The expression levels of powerful proinflammatory factors such as Nos2 and Ptgs2 was reduced in casp1(-/-) mice. Moreover, a hierarchical clustering analysis aimed at studying patterns of gene coexpression revealed large alterations in the hippocampal pattern of casp1(-/-) mice. Surprisingly, the expression of Adamts1 was increased in the hippocampus and adrenals of casp1(-/-) mice. CONCLUSIONS: The resilience of casp1(-/-) mice to SIRS lethality is associated with a lower inflammatory response, loss of hippocampal gene coexpression patterns, and increased hippocampal Adamts1 gene expression. The latter might be beneficial for casp1(-/-) mice, since ADAMTS1 is likely to play a role in neuronal plasticity. The mechanisms described here may help the development of either novel biomarkers or therapeutic targets against SIRS/sepsis.

The use of dried blood spot sampling for the measurement of HbA1c: a cross-sectional study.

BACKGROUND: The use of dried blood spot (DBS) sampling is an alternative to traditional venous blood collection, and particularly useful for people living in rural and remote areas, and for those who are infirm, house-bound or time-poor. The objective of this study was to assess whether the measurement of glycated haemoglobin A1c (HbA1c) in DBS samples provided comparative and acceptably precise results. METHODS: Venous and capillary blood samples were collected from 115 adult participants. After proper instruction, each participant punctured his/her own finger and collected capillary blood samples on pieces of a proprietary cellulose filter paper. Each filter paper was subsequently placed inside a breathable envelope, stored at room temperature, and processed on the same day (D0), four (D4), seven (D7) and fourteen (D14) days after collection. HbA1c was measured in duplicates/triplicates in whole venous blood (WB), capillary blood (capDBS) and venous blood placed on the matrix paper (venDBS), by turbidimetric inhibition immunoassay. Intra-assay coefficients of variation (CV) were calculated. DBS values were compared to WB results using linear regression, Bland-Altman plots and cross-validation models. RESULTS: Eleven and 56 patients had type 1 and type 2 diabetes mellitus, respectively. Mean HbA1c levels were 6.22 ± 1.11 % for WB samples (n = 115). The median intra-assay CV was lower than 3 % for WB and capDBS on all days. Results from capDBS and venDBS showed high correlation and agreement to WB results, with narrow 95 % limits of agreement (except for results from D14 samples), as observed in Bland-Altman plots. When capDBS values were applied to equations derived from regression analyses, results approached those of WB values. A cross-validation model showed that capDBS results on D0, D4 and D7 were close to the WB results, with prediction intervals that were narrow enough to be clinically acceptable. CONCLUSIONS: The measurement of HbA1c from DBS samples provided results that were comparable to results from WB samples, if measured up to seven days after collection. Intra-assay coefficients of variation were low, results were in agreement with the gold-standard, and prediction intervals were clinically acceptable. The measurement of HbA1c through DBS sampling may be considered in situations where traditional venipuncture is not available. TRIAL REGISTRATION: Australian New Zealand Clinical Trials Registry ID ACTRN12613000769785.

Tumor necrosis factor-induced cerebral insulin resistance in Alzheimer's disease links numerous treatment rationales.

The evident limitations of the amyloid theory of the pathogenesis of Alzheimer's disease are increasingly putting alternatives in the spotlight. We argue here that a number of independently developing approaches to therapy-including specific and nonspecific anti-tumor necrosis factor (TNF) agents, apolipoprotein E mimetics, leptin, intranasal insulin, the glucagon-like peptide-1 mimetics and glycogen synthase kinase-3 (GSK-3) antagonists-are all part of an interlocking chain of events. All these approaches inform us that inflammation and thence cerebral insulin resistance constitute the pathway on which to focus for a successful clinical outcome in treating this disease. The key link in this chain presently absent is a recognition by Alzheimer's research community of the long-neglected history of TNF induction of insulin resistance. When this is incorporated into the bigger picture, it becomes evident that the interventions we discuss are not competing alternatives but equally valid approaches to correcting different parts of the same pathway to Alzheimer's disease. These treatments can be expected to be at least additive, and conceivably synergistic, in effect. Thus the inflammation, insulin resistance, GSK-3, and mitochondrial dysfunction hypotheses are not opposing ideas but stages of the same fundamental, overarching, pathway of Alzheimer's disease pathogenesis. The insight this provides into progenitor cells, including those involved in adult neurogenesis, is a key part of this approach. This pathway also has therapeutic implications for other circumstances in which brain TNF is pathologically increased, such as stroke, traumatic brain injury, and the infectious disease encephalopathies.

Effects of leptin deficiency and replacement on cerebellar response to food-related cues.

Leptin affects eating behavior partly by altering the response of the brain to food-related stimuli. The effects of leptin on brain structure have been observed in the cerebellum, where leptin receptors are most densely expressed, but the function of leptin in the cerebellum remains unclear. We performed a nonrandomized, prospective interventional study of three adults with genetically mediated leptin deficiency. FMRI was recorded three times each year during years 5 and 6 of leptin replacement treatment. Session 1 of each year occurred after 10 months of continuous daily replacement, session 2 after 33-37 days without leptin, and session 3 at 14-23 days after daily replacement was restored. Statistical parametric mapping software (SPM5) was employed to contrast the fMRI blood oxygenation level-dependent response to images of high-calorie foods versus images of brick walls. Covariate analyses quantified the effects of the duration of leptin replacement and concomitant changes in body mass on the cerebral responses. Longer duration of replacement was associated with more activation by food images in a ventral portion of the posterior lobe of the cerebellum, while simultaneous decreases in body mass were associated with decreased activation in a more dorsal portion of the same lobe. These findings indicate that leptin replacement reversibly alters neural function within the posterior cerebellum and modulates plasticity-dependent brain physiology in response to food cues. The results suggest an underexplored role for the posterior cerebellum in the regulation of leptin-mediated processes related to food intake.

Pathophysiological basis of cardiovascular disease and depression: a chicken-and-egg dilemma.

OBJECTIVE: To describe the pathophysiological basis linking cardiovascular disease (CVD) and depression; to discuss the causal relationship between them, and to review the effects of antidepressant treatment on cardiovascular disease. METHOD: A review of the literature based on the PubMed database. DISCUSSION: Depression and cardiovascular disease are both highly prevalent. Several studies have shown that the two are closely related. They share common pathophysiological etiologies or co-morbidities, such as alterations in the hypothalamic-pituitary axis, cardiac rhythm disturbances, and hemorheologic, inflammatory and serotoninergic changes. Furthermore, antidepressant treatment is associated with worse cardiac outcomes (in case of tricyclics), which are not observed with selective serotonin reuptake inhibitors. CONCLUSION: Although there is a strong association between depression and cardiovascular disease, it is still unclear whether depression is actually a causal factor for CVD, or is a mere consequence, or whether both conditions share a common pathophysiological etiology. Nevertheless, both conditions must be treated concomitantly. Drugs other than tricyclics must be used, when needed, to treat the underlying depression and not as mere prophylactic of cardiac outcomes.

Neuroendocrine body weight regulation: integration between fat tissue, gastrointestinal tract, and the brain.

Human body weight is maintained at a fairly stable level regardless of changes in energy intake and energy expenditure. Compensatory mechanisms within the central nervous system (CNS), which regulate food intake and energy expenditure, are triggered by other central and peripheral signals. Peripherally, the main sources of those signals are the adipose tissue, gastrointestinal tract, and pancreas. The main signal originating from the adipose tissue is leptin, which promotes the activation of anorexigenic pathways in the CNS. Similarly, the central action of insulin also reduces food intake and stimulates catabolic pathways. The gastrointestinal tract contributes with several peptides that influence food intake, such as ghrelin, glucagon-like peptide 1 (GLP-1), peptide YY (PYY), oxyntomodulin (OXM), and cholecystokinin (CCK). Other substances secreted by the pancreas, such as pancreatic polypeptide (PP) and amylin, a hormone co-secreted with insulin, also affect energy balance. More recently, the endocannabinoid system has also been identified as a contributor in the maintenance of energy balance. Better understanding of these mechanistic systems involved in the regulation of energy metabolism will hopefully lead to the development of new therapeutic approaches against obesity, metabolic syndrome, and other nutritional disorders.

Cellular immunity before and after leptin replacement therapy.

BACKGROUND: The few identified leptin-deficient children have immune deficiency. AIMS: To evaluate whether a newly-identified leptin-deficient boy has immune defects; to assess the immune changes during leptin replacement. METHODS: A 5 year-old boy with congenital leptin deficiency was evaluated before, 2 weeks and 6 weeks after the initiation of recombinant methionyl human leptin. Thymic volume was measured by computed tomography. Humoral immunity was assessed by measuring levels of several immunoglobulins. Cellular immunity was evaluated by the analysis of lymphocyte proliferation in response to mitogens. Lymphocyte subsets were quantified by flow cytometry. RESULTS: At baseline, thymic volume was increased. The lymphocyte subsets count and humoral/cellular immunities were normal. After treatment, proliferative response to mitogens increased by 1.5- to 3-fold, and lymphocyte count decreased by 17%. CONCLUSIONS: Immune defects are not an obligatory feature of congenital leptin deficiency. Even in the absence of significant immune defects, leptin replacement therapy enhanced T-cell responsiveness.

MANAGEMENT OF ENDOCRINE DISEASE: Pitfalls on the replacement therapy for primary and central hypothyroidism in adults.

Hypothyroidism is one of the most common hormone deficiencies in adults. Most of the cases, particularly those of overt hypothyroidism, are easily diagnosed and managed, with excellent outcomes if treated adequately. However, minor alterations of thyroid function determine nonspecific manifestations. Primary hypothyroidism due to chronic autoimmune thyroiditis is largely the most common cause of thyroid hormone deficiency. Central hypothyroidism is a rare and heterogeneous disorder characterized by decreased thyroid hormone secretion by an otherwise normal thyroid gland, due to lack of TSH. The standard treatment of primary and central hypothyroidism is hormone replacement therapy with levothyroxine sodium (LT4). Treatment guidelines of hypothyroidism recommend monotherapy with LT4 due to its efficacy, long-term experience, favorable side effect profile, ease of administration, good intestinal absorption, long serum half-life and low cost. Despite being easily treatable with a daily dose of LT4, many patients remain hypothyroid due to malabsorption syndromes, autoimmune gastritis, pancreatic and liver disorders, drug interactions, polymorphisms in DIO2 (iodothyronine deiodinase 2), high fiber diet, and more frequently, non-compliance to LT4 therapy. Compliance to levothyroxine treatment in hypothyroidism is compromised by daily and fasting schedule. Many adult patients remain hypothyroid due to all the above mentioned and many attempts to improve levothyroxine therapy compliance and absorption have been made.

[Recombinant human TSH use in differentiated thyroid cancer]. / Uso do TSH humano recombinante no câncer diferenciado de tireóide.

Traditionally, the immediate treatment of patients with differentiated thyroid carcinoma (DTC) after total thyroidectomy (TT) is thyroid remnant ablation (TRA) with 131I, during hypothyroidism. Late follow-up of DCT includes suppressive doses of T4, serial measurements of thyroglobulin (Tg), whole body scan (WBS) with 131I and cervical ultrasound (US). In the last years, TRA with the aid of recombinant human TSH (rhTSH) has shown not only to avoid symptoms of hypothyroidism and a lower quality of life, but also to have the same efficacy as TRA during endogenous TSH elevation. Stimulated Tg with endogenous or exogenous TSH, 9 to 12 months after the initial treatment of DTC, associated with cervical US, is able to identify low-risk patients virtually cured of their disease, in whom TSH suppression does not need to be so strict, avoiding the heart and bone complications of prolonged exogenous thyrotoxicosis. Finally, in spite of the absence of randomized studies designed to evaluate the role of rhTSH in metastatic DTC disease, results of the combined treatment of rhTSH and 131I show a clinical benefit in the majority of treated patients.

Genetics of non-syndromic childhood obesity and the use of high-throughput DNA sequencing technologies.

BACKGROUND: Childhood obesity is a serious public health problem associated with the development of several chronic diseases, such as type 2 diabetes mellitus, dyslipidemia, and hypertension. The elevated prevalence of obesity is mostly due to inadequate diet and lifestyle, but it is also influenced by genetic factors. OBJECTIVES: To review recent advances in the field of the genetics of obesity. We summarize the list of genes associated with the rare non-syndromic forms of obesity, and explain their function. Furthermore, we discuss the technologies that are available for the genetic diagnosis of obesity. RESULTS: Several studies reported that single gene variants cause Mendelian forms of obesity, determined by mutations of major effect in single genes. Rare, non-syndromic forms of obesity are a result of loss-of-function mutations in genes that act on the development and function of the hypothalamus or the leptin-melanocortin pathway. These variants disrupt enzymes and receptors that play a role in energy homeostasis, resulting in severe early-onset obesity and endocrine dysfunctions. Different approaches and technologies have been used to understand the genetic background of obesity. Currently, whole genome and whole exome sequencing are important diagnostic tools to identify new genes and variants associated with severe obesity, but other approaches are also useful at individual or population levels, such as linkage analysis, candidate gene sequencing, chromosomal microarray analysis, and genome-wide association studies. CONCLUSIONS: The understanding of the genetic causes of obesity and the usefulness and limitations of the genetic diagnostic approaches can contribute to the development of new personalized therapeutic targets against obesity.

Role of the IL-1 Pathway in Dopaminergic Neurodegeneration and Decreased Voluntary Movement.

Interleukin-1 (IL-1), a proinflammatory cytokine synthesized and released by activated microglia, can cause dopaminergic neurodegeneration leading to Parkinson's disease (PD). However, it is uncertain whether IL-1 can act directly, or by exacerbating the harmful actions of other brain insults. To ascertain the role of the IL-1 pathway on dopaminergic neurodegeneration and motor skills during aging, we compared mice with impaired [caspase-1 knockout (casp1-/-)] or overactivated IL-1 activity [IL-1 receptor antagonist knockout (IL-1ra-/-)] to wild-type (wt) mice at young and middle age. Their motor skills were evaluated by the open-field and rotarod tests, and quantification of their dopamine neurons and activated microglia within the substantia nigra were performed by immunohistochemistry. IL-1ra-/- mice showed an age-related decline in motor skills, a reduced number of dopamine neurons, and an increase in activated microglia when compared to wt or casp1-/- mice. Casp1-/- mice had similar changes in motor skills and dopamine neurons, but fewer activated microglia cells than wt mice. Our results suggest that the overactivated IL-1 pathway occurring in IL-1ra-/- mice in the absence of inflammatory interventions (e.g., intracerebral injections performed in animal models of PD) increased activated microglia, decreased the number of dopaminergic neurons, and reduced their motor skills. Decreased IL-1 activity in casp1-/- mice did not yield clear protective effects when compared with wt mice. In summary, in the absence of overt brain insults, chronic activation of the IL-1 pathway may promote pathological aspects of PD per se, but its impairment does not appear to yield advantages over wt mice.

[Outcome of surgical treatment for acromegaly performed by a single neurosurgeon and cumulative meta-analysis]. / Resultados do tratamento cirúrgico na acromegalia com um único neurocirurgião e meta-análise cumulativa.

The aim of this retrospective study was to evaluate the results of transsphenoidal surgery in a group of patients with acromegaly who were operated by the same neurosurgeon. Our results were compared to those from a cumulative meta-analysis of 10 series (1,632 patients) published between 1992 and 2005. We followed 28 patients (17M/11F; 44.1 +/- 12.7 yr; 27 with macroadenomas; 86% being invasive) during 21.4 +/- 17.6 months after treatment. Patients were classified according to disease activity as follows: 1) controlled (CD): basal or mean GH < 2.5 ng/ml or nadir GH (OGTT) < 1 ng/ml and normal IGF-1; 2) uncontrolled (UCD): basal or mean GH > 2.5 ng/ml or nadir GH > 1 ng/ml and elevated IGF-1; 3) inadequately controlled (ICD): normal GH and elevated IGF-1 or elevated GH and normal IGF-1. After surgery, GH levels decreased from 61.7 +/- 101.1 ng/ml to 7.2 +/- 13.7 ng/ml (p< 0.001) and mean IGF-1 from 673.1 +/- 257.7 ng/ml to 471.2 +/- 285 ng/ml (p= 0.01). Biochemical remission rate was 57% [10 (35.5%) patients with CD and 6 (21.5%) with ICD], similar to the mean remission rate observed in the meta-analysis of surgical outcome of macroadenomas. Seven of 28 patients were submitted to surgical re-intervention (4 had been previously operated elsewhere and 3 by our neurosurgeon), with CD observed in 5 (71.5%) on follow-up. Cavernous sinuses invasion was more prevalent in UCD and ICD, whereas infundibular stalk deviation occurred only in patients with UCD. Remission rate was significantly higher in series where all surgical procedures were performed by the same surgeon (66% vs. 49%; p< 0.05). Thus, the surgeon's experience significantly improves the surgical outcome in acromegaly, especially in patients harboring large and invasive tumors, and re-intervention performed by an experienced surgeon should be considered in the algorithms for clinical management of this disease.

Association between circulating adipocytokine concentrations and microvascular complications in patients with type 2 diabetes mellitus: A systematic review and meta-analysis of controlled cross-sectional studies.

BACKGROUND: The adipocytokines leptin and adiponectin have been variously associated with diabetic microvascular complications. No comprehensive clinical data exist examining the association between adipocytokines and the presence of these complications. METHODS: This is a systematic review of cross-sectional studies comparing circulating adipocytokines in patients with type 2 diabetes mellitus (T2DM), with and without microvascular complications. Studies were retrieved from MEDLINE, EMBASE, Scopus and Cochrane databases. Study quality was evaluated using a modified Newcastle-Ottawa Scale. Meta-analysis was performed using an inverse-variance model, providing standardised mean differences (SMD) and 95% confidence intervals (CI). Heterogeneity was determined by I(2) statistic. RESULTS: Amongst 554 identified studies, 28 were included in the review. Study quality range was 3.5-9 (maximum 11). Higher leptin levels were associated with microalbuminuria (SMD=0.41; 95% CI=0.14-0.67; n=901; p=0.0003), macroalbuminuria (SMD=0.68; 95% CI=0.30-1.06; n=406; p=0.0004), and neuropathy (SMD=0.26; 95% CI=0.07-0.44; n=609; p=0.008). Higher adiponectin levels were associated with microalbuminuria (SMD=0.55; 95% CI=0.29-0.81, n=274; p<0.001), macroalbuminuria (SMD=1.37; 95% CI=0.78-1.97, n=246; p<0.00001), neuropathy (SMD=0.25; 95% CI=0.14-0.36; n=1516; p<0.00001), and retinopathy (SMD=0.38; 95% CI=0.25-0.51; n=1306; p<0.00001). Meta-regression suggested no influence of body mass index and duration of diabetes on effect size, and a weak trend in terms of age on effect size. DISCUSSION: Our meta-analysis suggests leptin and adiponectin levels are higher in T2DM patients with microvascular complications. Studies were limited by cross-sectional design. Large prospective analyses are required to validate these findings.

Treatment of hypothyroidism with levothyroxine plus liothyronine: a randomized, double-blind, crossover study.

OBJECTIVE: To compare the effects of a unique fixed combination levothyroxine/liothyronine (LT4/LT3) therapy in patients with primary hypothyroidism. SUBJECTS AND METHODS: This is a randomized, double-blind, crossover study. Adults with primary hypothyroidism (n = 32, age 42.6 ± 13.3, 30 females) on stable doses of LT4 for ≥ 6 months (125 or 150 µg/day) were randomized to continue LT4 treatment (G1) or to start LT4/LT3 therapy (75/15 µg/day; G2). After 8 weeks, participants switched treatments for 8 more weeks. Thyroid function, lipid profile, plasma glucose, body weight, electrocardiogram, vital signs, and quality of life (QoL) were evaluated at weeks 0, 8 and 16. RESULTS: Free T4 levels were significantly lower while on LT4/LT3 (G1: 1.07 ± 0.29 vs. 1.65 ± 0.46; G2: 0.97 ± 0.26 vs. 1.63 ± 0.43 ng/dL; P < 0.001). TSH and T3 levels were not affected by type of therapy. More patients on LT4/LT3 had T3 levels above the upper limit (15% vs. 3%). The combination therapy led to an increase in heart rate, with no significant changes in electrocardiogram or arterial blood pressure. Lipid profile, body weight and QoL remained unchanged. CONCLUSIONS: The combination therapy yielded significantly lower free T4 levels, with no changes in TSH or T3 levels. More patients on LT4/T3 had elevated T3 levels, with no significant alterations in the evaluated outcomes. No clear clinical benefit of the studied formulation could be observed. Future trials need to evaluate different formulations and the impact of the combined therapy in select populations with genetic polymorphisms.

Leptin treatment: facts and expectations.

Leptin has key roles in the regulation of energy balance, body weight, metabolism, and endocrine function. Leptin levels are undetectable or very low in patients with lipodystrophy, hypothalamic amenorrhea, and congenital leptin deficiency (CLD) due to mutations in the leptin gene. For these patients, leptin replacement therapy with metreleptin (a recombinant leptin analog) has improved or normalized most of their phenotypes, including normalization of endocrine axes, decrease in insulin resistance, and improvement of lipid profile and hepatic steatosis. Remarkable weight loss has been observed in patients with CLD. Due to its effects, leptin therapy has also been evaluated in conditions where leptin levels are normal or high, such as common obesity, diabetes (types 1 and 2), and Rabson-Mendenhall syndrome. A better understanding of the physiological roles of leptin may lead to the development of leptin-based therapies for other prevalent disorders such as obesity-associated nonalcoholic fatty liver disease, depression and dementia.

New advances in the treatment of generalized lipodystrophy: role of metreleptin.

Recombinant methionyl human leptin or metreleptin is a synthetic leptin analog that has been trialed in patients with leptin-deficient conditions, such as leptin deficiency due to mutations in the leptin gene, hypothalamic amenorrhea, and lipodystrophy syndromes. These syndromes are characterized by partial or complete absence of adipose tissue and hormones derived from adipose tissue, most importantly leptin. Patients deficient in leptin exhibit a number of severe metabolic abnormalities such as hyperglycemia, hypertriglyceridemia, and hepatic steatosis, which can progress to diabetes mellitus, acute pancreatitis, and hepatic cirrhosis, respectively. For the management of these abnormalities, multiple therapies are usually required, and advanced stages may be progressively difficult to treat. Following many successful trials, the US Food and Drug Administration approved metreleptin for the treatment of non-HIV-related forms of generalized lipodystrophy. Leptin replacement therapy with metreleptin has, in many cases, reversed these metabolic complications, with improvements in glucose-insulin-lipid homeostasis, and regression of fatty liver disease. Besides being effective, a daily subcutaneous administration of metreleptin is generally safe, but the causal association between metreleptin and immune complications (such as lymphoma) is still unclear. Moreover, further investigation is needed to elucidate mechanisms by which metreleptin leads to the development of anti-leptin antibodies. Herein, we review clinical aspects of generalized lipodystrophy and the pharmacological profile of metreleptin. Further, we examine studies that assessed the safety and efficacy of metreleptin, and outline some clinical perspectives on the drug.

TSH levels are associated with increased risk of thyroid carcinoma in patients with nodular disease.

INTRODUCTION: Several studies have shown an increased risk of thyroid malignancies in patients with elevated TSH levels, even if these levels fell within the normal range. The aim of this study was to evaluate the relationship between TSH and risk of malignancy in patients with thyroid nodules. MATERIAL AND METHODS: We included 622 patients with thyroid nodules evaluated by fine needle aspiration and/or thyroidectomy and diagnosed by cytology or histology. Clinical and laboratory data, such as gender, weight, ultrasound findings, serum TSH, and free T4, were obtained from medical records or collected during each patient's first visit to our centre, prior to any intervention. RESULTS: Thyroid cancer was more prevalent in males (p = 0.012) and in patients with a solitary nodule (p < 0.01). Malignant tumours were predominantly solid, whereas benign tumours were solid or mixed (p = 0.053). The carcinoma risk in patients with thyroid nodules increased with increasing serum TSH concentration, with a significant elevation in patients with serum TSH levels above 1.64 mU/L (p < 0.001). This relationship persisted even when the subgroup of patients undergoing thyroidectomy was analysed separately. Patients with follicular lesions presented with significantly higher TSH levels compared to patients with benign cytology (p < 0.001). We also found correlation between elevated TSH and tumour size (p = 0.005). CONCLUSIONS: Our results suggest that in patients with nodular thyroid disease the carcinoma risk rose in parallel with serum TSH concentration, with significant increases evident in patients with serum TSH greater than 1.64 mU/L.

Whole exome sequencing of extreme morbid obesity patients: translational implications for obesity and related disorders.

Whole-exome sequencing (WES) is a new tool that allows the rapid, inexpensive and accurate exploration of Mendelian and complex diseases, such as obesity. To identify sequence variants associated with obesity, we performed WES of family trios of one male teenager and one female child with severe early-onset obesity. Additionally, the teenager patient had hypopituitarism and hyperprolactinaemia. A comprehensive bioinformatics analysis found de novo and compound heterozygote sequence variants with a damaging effect on genes previously associated with obesity in mice (LRP2) and humans (UCP2), among other intriguing mutations affecting ciliary function (DNAAF1). A gene ontology and pathway analysis of genes harbouring mutations resulted in the significant identification of overrepresented pathways related to ATP/ITP (adenosine/inosine triphosphate) metabolism and, in general, to the regulation of lipid metabolism. We discuss the clinical and physiological consequences of these mutations and the importance of these findings for either the clinical assessment or eventual treatment of morbid obesity.