Role of leptin in energy expenditure: the hypothalamic perspective

Triiodothyronine and leptin repletion in humans similarly reverse weight-loss-induced changes in skeletal muscle

Subjects maintaining a ≥10% dietary weight loss exhibit decreased circulating concentrations of bioactive thyroid hormones and increased skeletal muscle work efficiency largely due to increased expression of more-efficient myosin heavy chain (MHC) isoforms (MHC I) and significantly mediated by the adipocyte-derived hormone leptin. The primary purpose of this study was to examine the effects of triiodothyronine (T₃) repletion on energy homeostasis and skeletal muscle physiology in weight-reduced subjects and to compare these results with the effects of leptin repletion. Nine healthy in-patients with obesity were studied at usual weight (Wt_initial) and following a 10% dietary weight loss while receiving 5 wk of a placebo (Wt_-10%placebo) or T₃ (Wt_-10%T3) in a single-blind crossover design. Primary outcome variables were skeletal muscle work efficiency and vastus lateralis muscle mRNA expression. These results were compared with the effects of leptin repletion in a population of 22 subjects, some of whom participated in a previous study. At Wt_-10%placebo, skeletal muscle work efficiency and relative expression of the more-efficient/less-efficient MHC I/MHC II isoforms were significantly increased and the ratio of the less-efficient to the more-efficient sarco(endo)plasmic reticulum Ca²⁺-ATPase isoforms (SERCA1/SERCA2) was significantly decreased. These changes were largely reversed by T₃ repletion to a degree similar to the changes that occurred with leptin repletion. These data support the hypothesis that the effects of leptin on energy expenditure in weight-reduced individuals are largely mediated by T₃ and suggest that further study of the possible role of thyroid hormone repletion as adjunctive therapy to help sustain weight loss is needed.

The relationship between resting energy expenditure and thyroid hormones in response to short-term weight loss in severe obesity

Background

Regulating thermogenesis is a major task of thyroid hormones (THs), and involves TH-responsive energetic processes at the central and peripheral level. In severe obesity, little is known on the relationship between THs and resting energy expenditure (REE) before and after weight loss.

Methods

We enrolled 100 euthyroid subjects with severe obesity who were equally distributed between genders. Each was examined before and after completion of a 4-wk inpatient multidisciplinary dieting program and subjected to measurement of thyroid function, REE, fat-free mass (FFM, kg) and percent fat mass (FM).

Results

Baseline REE was lower than predicted in 70 obese patients, and overall associated with BMI, FFM and FM but not thyroid-related parameters. By the study end, both BMI and REE decreased (5.5% and 4.1%, p<0.001 vs. baseline) and their percent changes were significantly associated (p<0.05), while no association related percent changes of REE and FFM or FM. Individually, REE decreased in 66 and increased in 34 patients irrespective of gender, BMI and body composition. Weight loss significantly impacted TSH (-6.3%), FT3 (-3.3%) and FT4 levels (3.9%; p<0.001 for all). By the study end, a significant correlation became evident between REE and FT4 (r = 0.42, p<0.001) as well as FT3 (r = 0.24, p<0.05). In stepwise multivariable regression analysis, however, neither THs nor body composition entered the regression equation for REE response to weight loss.

Conclusions

In severe obesity, short-term weight loss discloses a positive relationship between REE and THs.

Acute physical exercise increases leptin-induced hypothalamic extracellular signal-regulated kinase1/2 phosphorylation and thermogenesis of obese mice

The obesity is a result of energy imbalance and the increase in thermogenesis seems an interesting alternative for the treatment of this disease. The mechanism of energy expenditure through thermogenesis is tightly articulated in the hypothalamus by leptin. The hypothalamic extracellular signal-regulated kinase-1/2 (ERK1/2) is a key mediator of the thermoregulatory effect of leptin and mediates the sympathetic signal to the brown adipose tissue (BAT). In this context, physical exercise is one of the main interventions for the treatment of obesity. Thus, this study aimed to verify the effects of acute physical exercise on leptin-induced hypothalamic ERK1/2 phosphorylation and thermogenesis in obese mice. Here we showed that acute physical exercise reduced the fasting glucose of obese mice and increased leptin-induced hypothalamic p-ERK1/2 and uncoupling protein 1 (UCP1) content in BAT ( P < 0.05). These molecular changes are accompanied by an increased oxygen uptake (VO ₂ ) and heat production in obese exercised mice ( P < 0.05). The increased energy expenditure in the obese exercised animals occurred independently of changes in spontaneous activity. Thus, this is the first study demonstrating that acute physical exercise can increase leptin-induced hypothalamic ERK1/2 phosphorylation and energy expenditure of obese mice.

Does circulating leptin play a role in energy expenditure?

OBJECTIVES

It has been demonstrated that leptin influences the energy balance by regulating appetite and increasing energy expenditure (EE). However, the relationship between circulating leptin and EE is confounded owing to variations in body composition. The aim of this study was to determine the role of circulating leptin in energy regulation and to examine whether the leptin-mediated changes in EE are associated with adiposity among healthy adults living in Singapore.

METHODS

We conducted a cross-sectional study of 300 participants (112 men). Resting metabolic rate (RMR) was measured by indirect calorimetry. Body composition (i.e., fat mass [FM] and fat-free mass [FFM]) was measured by dual-energy x-ray absorptiometry. Serum leptin levels were determined by radioimmunoassay.

RESULTS

There were strong correlations between circulating leptin levels, FM, and RMR in healthy men and women. After normalization of RMR by a power function model (kcal·kg FFM^0.86·d^-1), the influence of FFM can be effectively removed. The normalized RMR was significantly associated with both FM (r = 0.28, P < 0.001) and log leptin (r = 0.35, P < 0.001). In the stepwise multiple regression analysis, leptin level is the major predictor for normalized RMR, accounting for 12% of the variation. In contrast, FM did not explain any variation in normalized RMR.

CONCLUSION

Leptin may be a more significant predictor of normalized RMR than FM per se. The contribution of FM to RMR could be via a mechanism that is related to leptin-dependent responses involved in energy homeostasis.

Insulin as a hormone regulator of the synthesis and release of leptin by white adipose tissue

Leptin and its receptor are widely distributed in several tissues, mainly in white adipose tissue. The serum leptin is highly correlated with body mass index in rodents and humans, being documented that leptin levels reduces in the fasting state and increase during refeeding, similarly to insulin release by pancreatic islets. Insulin appears to increase leptin mRNA and protein expression and its release by adipocytes. Some studies have suggested that insulin acts through the activation of the transcription factors: sterol regulatory element binding protein 1 (SREBP1), CCAAT enhancer binding protein-α (C/EBP-α) and specificity protein 1 (Sp1). Insulin stimulates the release of preformed and newly synthesized leptin by adipocytes through its signaling cascade. Its effects are blocked by inhibitors of the insulin signaling pathway, as well as by inhibitors of protein synthesis and agents that increase the intracellular cAMP. The literature data suggest that chronic hyperinsulinemia increases serum leptin levels in humans and rodents. In this review, we summarized the most updated knowledge on the effects of insulin on serum leptin levels, presenting the cell mechanisms that control leptin synthesis and release by the white adipose tissue.

Leptin stimulates tissue rat mast cell pro-inflammatory activity and migratory response

Objective

The aim of this study was to determine whether leptin, a member of the adipocytokines involved in immune and inflammatory response regulation, may influence some aspects of mast cell biology.

Materials and methods

Experiments were done in vitro on fully mature tissue rat mast cells isolated from the peritoneal cavity, and leptin was used at concentrations 0.001–100 ng/ml. The effect of leptin on mast cell degranulation (histamine release assay), intracellular Ca²⁺ level (fluorimetry), pro-inflammatory mediator release (ELISA technique), surface receptor expression (flow cytometry and confocal microscopy), and migration (Boyden microchamber assay) was estimated.

Results

Leptin was found to stimulate mast cells to degranulation and histamine release. It induced the intracellular Ca²⁺ increase, as well. In response to leptin stimulation, mast cells generated and released cysLTs and chemokine CCL3. Leptin-induced upregulation of CYSLTR1 and CYSLTR2 surface expression was observed. Moreover, this adipocytokine stimulated mast cells to migratory response, even in the absence of extracellular matrix (ECM) proteins.

Conclusions

Our observations clearly documented that leptin promotes the pro-inflammatory activity of mast cells, and it thereby engages these cells in the inflammatory processes.

Hypothalamic endoplasmic reticulum stress as a key mediator of obesity-induced leptin resistance

Obesity is an epidemic disease that is increasing worldwide and is a major risk factor for many metabolic diseases. However, effective agents for the prevention or treatment of obesity remain limited. Therefore, it is urgent to clarify the pathophysiological mechanisms underlying the development and progression of obesity and exploit potential agents to cure and prevent this disease. According to a recent study series, obesity is associated with the development of endoplasmic reticulum stress and the activation of its stress responses (unfolded protein response) in metabolically active tissues, which contribute to the development of obesity-related insulin and leptin resistance, inflammation and energy imbalance. Hypothalamic endoplasmic reticulum stress is the central mechanism underlying the development of obesity-associated leptin resistance and disruption of energy homeostasis; thus, targeting endoplasmic reticulum stress offers a promising therapeutic strategy for improving leptin sensitivity, increasing energy expenditure and ultimately combating obesity. In this review, we highlight the relationship between and mechanism underlying hypothalamic endoplasmic reticulum stress and obesity-associated leptin resistance and energy imbalance and provide new insight regarding strategies for the treatment of obesity.

Do sodium-glucose co-transporter-2 inhibitors prevent heart failure with a preserved ejection fraction by counterbalancing the effects of leptin? A novel hypothesis

Sodium-glucose co-transporter-2 (SGLT2) inhibitors reduce the risk of serious heart failure events in patients with type 2 diabetes, but little is known about mechanisms that might mediate this benefit. The most common heart failure phenotype in type 2 diabetes is obesity-related heart failure with a preserved ejection fraction (HFpEF). It has been hypothesized that the synthesis of leptin in this disorder leads to sodium retention and plasma volume expansion as well as to cardiac and renal inflammation and fibrosis. Interestingly, leptin-mediated neurohormonal activation appears to enhance the expression of SGLT2 in the renal tubules, and SGLT2 inhibitors exert natriuretic actions at multiple renal tubular sites in a manner that can oppose the sodium retention produced by leptin. In addition, SGLT2 inhibitors reduce the accumulation and inflammation of perivisceral adipose tissue, thus minimizing the secretion of leptin and its paracrine actions on the heart and kidneys to promote fibrosis. Such fibrosis probably contributes to the impairment of cardiac distensibility and glomerular function that characterizes obesity-related HFpEF. Ongoing clinical trials with SGLT2 inhibitors in heart failure are positioned to confirm or refute the hypothesis that these drugs may favourably influence the course of obesity-related HFpEF by their ability to attenuate the secretion and actions of leptin.

Is leptin resistance the cause or the consequence of diet-induced obesity?

BACKGROUND/OBJECTIVES

Obesity is strongly associated with leptin resistance. It is unclear whether leptin resistance results from the (over)consumption of energy-dense diets or if reduced leptin sensitivity is also a pre-existing factor in rodent models of diet-induced obesity (DIO). We here tested whether leptin sensitivity on a chow diet predicts subsequent weight gain and leptin sensitivity on a free choice high-fat high-sucrose (fcHFHS) diet.

METHODS

Based upon individual leptin sensitivity on chow diet, rats were grouped in leptin sensitive (LS, n = 22) and leptin resistant (LR, n = 19) rats (P = 0.000), and the development of DIO on a fcHFHS diet was compared. The time-course of leptin sensitivity was measured over weeks in individual rats.

RESULTS

Both on a chow and a fcHFHS diet, high variability in leptin sensitivity was observed between rats, but not over time per individual rat. Exposure to the fcHFHS diet revealed that LR rats were more prone to develop DIO (P = 0.013), which was independent of caloric intake (p ≥ 0.320) and the development of diet-induced leptin resistance (P = 0.769). Reduced leptin sensitivity in LR compared with LS rats before fcHFHS diet exposure, was associated with reduced leptin-induced phosphorylated signal transducer and activator of transcription 3 (pSTAT3) levels in the dorsomedial and ventromedial hypothalamus (P ≤ 0.049), but not the arcuate nucleus (P = 0.558).

CONCLUSIONS

A pre-existing reduction in leptin sensitivity determines the susceptibility to develop excessive DIO after fcHFHS diet exposure. Rats with a pre-existing reduction in leptin sensitivity develop excessive DIO without eating more calories or altering their leptin sensitivity.

NPV-BSK805, an Antineoplastic Jak2 Inhibitor Effective in Myeloproliferative Disorders, Causes Adiposity in Mice by Interfering With the Action of Leptin

The pathophysiology of body weight gain that is observed in patients suffering from myeloproliferative neoplasms treated with inhibitors of the janus kinase (Jak) 1 and 2 pathway remains unknown. Here we hypothesized that this class of drugs interferes with the metabolic actions of leptin, as this hormone requires functional Jak2 signaling. To test this, C57BL/6J chow-fed mice received either chronic intraperitoneal (ip) or repeated intracerebroventricular (icv) administration of the selective Jak2 inhibitor NVP-BSK805, which was proven efficacious in treating polycythemia in rodents. Changes in food intake, body weight and body composition were recorded. Icv NVP-BSK805 was combined with ip leptin to evaluate ability to interfere with the action of this hormone on food intake and on induction of hypothalamic phosphorylation of signal transducer and activator of transcription 3 (STAT3). We found that chronic peripheral administration of NVP-BSK805 did not alter food intake, but increased fat mass and feed efficiency. The increase in fat mass was more pronounced during repeated icv administration of the compound, suggesting that metabolic effects were related to molecular interference in brain structures regulating energy balance. Accordingly, acute icv administration of NVP-BSK805 prevented the ability of leptin to decrease food intake and body weight by impeding STAT3 phosphorylation within the hypothalamus. Consequently, acute icv administration of NVP-BSK805 at higher dose induced hyperphagia and body weight gain. Our results provide evidence for a specific anabolic effect exerted by antineoplastic drugs targeting the Jak2 pathway, which is due to interference with the actions of leptin. Consequently, assessment of metabolic variables related to increased fat mass gain should be performed in patients treated with Jak2 inhibitors.

Control of Energy Expenditure by AgRP Neurons of the Arcuate Nucleus: Neurocircuitry, Signaling Pathways, and Angiotensin

PURPOSE OF REVIEW

Here, we review the current understanding of the functional neuroanatomy of neurons expressing Agouti-related peptide (AgRP) and the angiotensin 1A receptor (AT_1A) within the arcuate nucleus (ARC) in the control of energy balance.

RECENT FINDINGS

The development and maintenance of obesity involves suppression of resting metabolic rate (RMR). RMR control is integrated via AgRP and proopiomelanocortin neurons within the ARC. Their projections to other hypothalamic and extrahypothalamic nuclei contribute to RMR control, though relatively little is known about the contributions of individual projections and the neurotransmitters involved. Recent studies highlight a role for AT_1A, localized to AgRP neurons, but the specific function of AT_1A within these cells remains unclear. AT_1A functions within AgRP neurons to control RMR, but additional work is required to clarify its role within subpopulations of AgRP neurons projecting to distinct second-order nuclei, and the molecular mediators of its signaling within these cells.

Insights into the neurochemical signature of the Innervation of Beige Fat

Objective

The potential for brown adipose tissue (BAT) to be targeted as a therapeutic option to combat obesity has been heightened by the discovery of a brown–like form of inducible “beige” adipose tissue in white fat which has overlapping structural and functional properties to “classical” BAT. The likelihood that both beige and brown fat are recruited functionally by neural mechanisms, taken together with the lack of a detailed understanding of the nature of changes in the nervous system when white adipose tissue (WAT) is transformed to brown, provides the impetus for this study. Here, we aim to identify whether there is a shift in the gene expression profile in neurons directly innervating inguinal white adipose tissue (iWAT) that has undergone “beiging” to a signature that is more similar to neurons projecting to BAT.

Methods

Two groups of rats, one housed at thermoneutrality (27 °C) and the other exposed to cold (8 °C) for 7 days, were killed, and their T13/L1 ganglia, stellate ganglion (T1/T2), or superior cervical ganglion (SCG, C2/3) removed. This approach yielded ganglia containing neurons that innervate either beiged white fat (8 °C for 7 days), inguinal WAT (27 °C for 7 days), BAT (both 27 °C and 8 °C for 7 days) or non-WAT (8 °C for 7 days), the latter included to isolate changes in gene expression that were more aligned with a response to cold exposure than the transformation of white to beige adipocytes. Bioinformatics analyses of RNA sequencing data was performed followed by Ingenuity Pathway Analysis (IPA) to determine differential gene expression and recruitment of biosynthetic pathways.

Results

When iWAT is “beiged” there is a significant shift in the gene expression profile of neurons in sympathetic ganglia (T13/L1) innervating this depot toward a gene neurochemical signature that is similar to the stellate ganglion projecting to BAT. Bioinformatics analyses of “beiging” related genes revealed upregulation of genes encoding neuropeptides proopiomelanocortin (POMC) and calcitonin-gene related peptide (CGRP) within ganglionic neurons. Treatment of differentiated 3T3L1 adipocytes with αMSH, one of the products cleaved from POMC, results in an elevation in lipolysis and the beiging of these cells as indicated by changes in gene expression markers of browning (Ucp1 and Ppargc1a).

Conclusion

These data indicate that, coincident with beiging, there is a shift toward a “brown-like” neurochemical signature of postganglionic neurons projecting to inguinal white fat, an increased expression of POMC, and, consistent with a causative role for this prohormone in beiging, an αMSH-mediated increase in beige gene markers in isolated adipocytes.

•

RNA Seq showed shifts in neuronal gene expression following browning of white fat.

•

Gene expression in ganglia projecting to white fat became brown-like with beiging.

•

Bioinformatics analyses revealed neuronal gene candidates associated with beiging.

•

Prominent gene candidates associated with beiging included POMC and CGRP.

•

POMC cleavage product α-MSH caused beiging of cultured fat cells.

Inhibition of Adipocyte Differentiation by Anthocyanins Isolated from the Fruit of Vitis coignetiae Pulliat is Associated with the Activation of AMPK Signaling Pathway

Anthocyanins are naturally occurring water-soluble polyphenolic pigments in plants that have been shown to protect against cardiovascular diseases, and certain cancers, as well as other chronic human disorders. However, the anti-obesity effects of anthocyanins are not fully understood. In this study, we investigated the effects of anthocyanins isolated from the fruit of Vitis coignetiae Pulliat on the adipogenesis of 3T3-L1 preadipocytes. Our data indicated that anthocyanins attenuated the terminal differentiation of 3T3-L1 preadipocytes, as confirmed by a decrease in the number of lipid droplets, lipid content, and triglyceride production. During this process, anthocyanins effectively enhanced the activation of the AMP-activated protein kinase (AMPK); however, this phenomenon was inhibited by the co-treatment of compound C, an inhibitor of AMPK. Anthocyanins also inhibited the expression of adipogenic transcription factors, including peroxisome proliferator-activated receptor-γ, CCAAT/enhancer-binding protein a and b, and sterol regulatory element-binding protein-1c. In addition, anthocyanins were found to potently inhibit the expression of adipocyte-specific genes, including adipocyte fatty acid-binding protein, leptin, and fatty acid synthase. These results indicate that anthocyanins have potent anti-obesity effects due to the inhibition of adipocyte differentiation and adipogenesis, and thus may have applications as a potential source for an anti-obesity functional food agent.

Endothelial cell leptin receptors, leptin and interleukin-8 in the pathogenesis of preeclampsia: An in-vitro study

Objective:

Increased leptin hormone and leptin receptor may enhance the generation of proinflammatory cytokines by endothelial cells and lead to endothelial dysfunction. This study assessed the umbilical cord endothelial leptin receptor levels in preeclampsia and investigated the effect of leptin on endothelial interleukin-8 (IL-8) production.

Materials and Methods:

The association between IL-8 levels with leptin stimulation was investigated in leptin-treated human endothelial cells. Endothelial cell leptin receptor levels were evaluated using immunohistochemistry staining, and endothelial IL-8 protein expression by Western blot analysis. Data are presented as mean ± standard error of the mean (SEM). Statistical significance was analyzed using Student’s t-test or Mann-Whitney U test and one-way analysis of variance.

Results:

Leptin receptor immunoreactivity increased significantly in umbilical cord venous and arterial endothelial cells in normal pregnancy (n=12) compared with preeclampsia (n=7) endothelial cells. The corresponding preeclampsia versus control histologic scores (mean ± SEM) were 67.9±8.8 vs. 127.6±23.1, (p=0.011) for the leptin receptor and 55.4±8,0 vs. 93.7±17.1 (p=0.035), respectively, for the vein endothelial cells. Leptin treatment significantly increased IL-8 protein levels (control vs. 100 and 1000 ng/mL, p=0.003).

Conclusion:

The findings of increased umbilical cord endothelial leptin receptor levels in preeclampsia and increased endothelial IL-8 expression with exposure to higher leptin concentrations may indicate the contribution of leptin to endothelial dysfunction and increased neutrophil-endothelial interaction, which are significant pathophysiologic features of preeclampsia.

The effects of chronic testosterone administration on body weight, food intake, and fat weight were age-dependent

Previously, we showed that chronic testosterone administration increased body weight (BW) and food intake (FI), but did not alter fat weight, in young female rats. To examine our hypothesis that the effects of androgens on BW, FI and body composition might be age-dependent, the effects of chronic testosterone administration were evaluated in rats of different ages; i.e., young and middle-aged rats. Although chronic testosterone administration increased BW gain, FI, and feed efficiency in both young and middle-aged rats, it increased visceral fat weight in middle-aged rats, but not in young rats. Therefore, it is possible that testosterone promotes the conversion of energy to adipose tissue and exacerbates fat accumulation in older individuals. In addition, although the administration of testosterone increased the serum leptin level, it did not alter hypothalamic neuropeptide Y mRNA expression in middle-aged rats. On the contrary, the administration of testosterone did not affect the serum leptin levels of young rats. Thus, testosterone might induce hypothalamic leptin resistance, which could lead to fat accumulation in older individuals. Testosterone might disrupt the mechanisms that protect against adiposity and hyperphagia and represent a risk factor for excessive body weight and obesity, especially in older females.

Ethanol extracts of Aster yomena (Kitam.) Honda inhibit adipogenesis through the activation of the AMPK signaling pathway in 3T3-L1 preadipocytes

The leaves of Aster yomena (Kitam.) Honda have long been used as a traditional herb for treating disorders including coughs, asthma, and insect bites. According to recent studies, A. yomena leaf extracts have several pharmacological properties, including anti-inflammatory, antioxidant, and anti-asthmatic activities. However, little information is available regarding their anti-obesity effect. In this study, we investigated the inhibitory effect of the ethanol extracts of A. yomena leaves (EEAY) on adipocyte differentiation and adipogenesis using 3T3-L1 preadipocytes. When 3T3-L1 preadipocytes were treated with various concentrations of EEAY (ranging from non-toxic), the number of lipid droplets, lipid content, and triglyceride production, the typical characteristics of adipocytes, were suppressed in a concentration-dependent manner. During this process, EEAY significantly reduced the expression of adipogenic transcription factors, including peroxisome proliferator-activated receptor-γ, CCAAT/enhancer-binding protein α and β, and sterol regulatory element-binding protein-1c. In addition, EEAY was also found to potently inhibit the expression of adipocyte-specific genes, including adipocyte fatty acid-binding protein and leptin. In particular, EEAY treatment effectively enhanced the activation of the AMP-activated protein kinase (AMPK) signaling pathway; however, the co-treatment with compound C, an inhibitor of AMPK, significantly restored the EEAY-induced inhibition of pro-adipogenic transcription factors and adipocyte-specific genes. These results indicate that EEAY may exert an anti-obesity effect by controlling the AMPK signaling pathway, suggesting that the leaf extract of A. yomena may be a potential anti-obesity agent.

The Role of the Autonomic Nervous System in the Pathophysiology of Obesity

Obesity is reaching epidemic proportions globally and represents a major cause of comorbidities, mostly related to cardiovascular disease. The autonomic nervous system (ANS) dysfunction has a two-way relationship with obesity. Indeed, alterations of the ANS might be involved in the pathogenesis of obesity, acting on different pathways. On the other hand, the excess weight induces ANS dysfunction, which may be involved in the haemodynamic and metabolic alterations that increase the cardiovascular risk of obese individuals, i.e., hypertension, insulin resistance and dyslipidemia. This article will review current evidence about the role of the ANS in short-term and long-term regulation of energy homeostasis. Furthermore, an increased sympathetic activity has been demonstrated in obese patients, particularly in the muscle vasculature and in the kidneys, possibily contributing to increased cardiovascular risk. Selective leptin resistance, obstructive sleep apnea syndrome, hyperinsulinemia and low ghrelin levels are possible mechanisms underlying sympathetic activation in obesity. Weight loss is able to reverse metabolic and autonomic alterations associated with obesity. Given the crucial role of autonomic dysfunction in the pathophysiology of obesity and its cardiovascular complications, vagal nerve modulation and sympathetic inhibition may serve as therapeutic targets in this condition.

The Gene-Lifestyle Interaction on Leptin Sensitivity and Lipid Metabolism in Adults: A Population Based Study

Background: Obesity has been associated with leptin resistance and this might be caused by genetic factors. The aim of this study was to investigate the gene-lifestyle interaction between −866G/A UCP2 (uncoupling protein 2) gene polymorphism, dietary intake and leptin in a population based study. Methods: This is a cross sectional study conducted in adults living at urban area of Yogyakarta, Indonesia. Data of adiposity, lifestyle, triglyceride, high density lipoprotein (HDL) cholesterol, leptin and UCP2 gene polymorphism were obtained in 380 men and female adults. Results: UCP2 gene polymorphism was not significantly associated with adiposity, leptin, triglyceride, HDL cholesterol, dietary intake and physical activity (all p > 0.05). Leptin was lower in overweight subjects with AA + GA genotypes than those with GG genotype counterparts (p = 0.029). In subjects with AA + GA genotypes there was a negative correlation between leptin concentration (r = −0.324; p < 0.0001) and total energy intake and this correlation was not seen in GG genotype (r = −0.111; p = 0.188). Conclusions: In summary, we showed how genetic variation in −866G/A UCP2 affected individual response to leptin production. AA + GA genotype had a better leptin sensitivity shown by its response in dietary intake and body mass index (BMI) and this explained the protective effect of A allele to obesity.