Vojtech Hainer

Leptin-melanocortin pathway plays an essential role in the body weight regulation. Enhanced melanocortin signaling in the hypothalamus results in both decreased food intake and increased energy expenditure. The discovery of monogenic obesities with dysfunction of melanocortin-4 receptor (MC4R) greatly contributed to understanding of energy balance regulation. This review presents phenotypical characterization and prevalence of the MC4R gene mutations. Genome-wide association studies revealed that MC4R gene is significantly related not only to monogenic obesities but also to common obesity. An interaction of variants in the MC4R gene with fat mass and obesity associated (FTO) gene significantly increases the risk for obesity, particularly in adolescence. On the other hand, about 15 % of the MC4R gene variants result in a gain of function that protects against obesity and is associated with favorable metabolic profile. Long-term attempts to activate the MC4R have recently been finalized by a discovery of setmelanotide, a novel specific MC4R agonist that is devoid of untoward cardiovascular side-effects. The employment of specific MC4R agonists may open new horizons not only in the treatment of rare monogenic obesities but also in some common obesities where stimulation of MC4R could be achieved.

The recently published paper entitled ‘Obesity management in Europe: current status and objectives for the future' (Obes Facts 2016;9:273-283) summarizes the results of a survey on obesity management conducted in 23 member countries of the European Association for the Study of Obesity (EASO) [1]. The team of authors includes experts both in obesity management and in obesity prevention and emphasizes the important role of preventive measures in changing the obesogenic environment to a leptogenic one and thus contributing to the improvement of obesity management across Europe.

Mirabegron is the first β3-adrenoreceptor (AR) agonist which was approved for the treatment of overactive bladder (OAB) in the United States, Japan, the European Union, and Canada at a dose of 50 m...

Associations between different infectious agents and obesity have been reported in humans for over thirty years. In many cases, as in nosocomial infections, this relationship reflects the greater susceptibility of obese individuals to infection due to impaired immunity. In such cases, the infection is not related to obesity as a causal factor but represents a complication of obesity. In contrast, several infections have been suggested as potential causal factors in human obesity. However, evidence of a causal linkage to human obesity has only been provided for adenovirus 36 (Adv36). This virus activates lipogenic and proinflammatory pathways in adipose tissue, improves insulin sensitivity, lipid profile and hepatic steatosis. The E4orf1 gene of Adv36 exerts insulin senzitizing effects, but is devoid of its pro-inflammatory modalities. The development of a vaccine to prevent Adv36-induced obesity or the use of E4orf1 as a ligand for novel antidiabetic drugs could open new horizons in the prophylaxis and treatment of obesity and diabetes. More experimental and clinical studies are needed to elucidate the mutual relations between infection and obesity, identify additional infectious agents causing human obesity, as well as define the conditions that predispose obese individuals to specific infections.

Adolescence, due to transient pubertal insulin resistance (IR), is associated with a higher risk for disturbances of glucose metabolism. The aim of our study was 1) to investigate the prevalence of disturbances of glucose metabolism, 2) to define gender specific homeostasis model assessment of insulin resistance (HOMA-IR) thresholds associated with increased cardiometabolic risks and 3) to provide predictors of HOMA-IR. The studied cohort consisted of Czech adolescents aged 13.0-17.9 years: 1,518 individuals of general population and three studied groups according weight category (615 normal weight, 230 overweight and 683 obese). The prevalence of IR, impaired fasting glucose (IFG) and type 2 diabetes was assessed. Risky HOMA-IR thresholds based on components of metabolic syndrome were investigated. HOMA-IR prediction was calculated taking into account age, blood pressure, multiple anthropometric, biochemical and hormonal parameters. In general population cohort, the prevalence of IFG and type 2 diabetes was 7.0% and <0.5%, respectively. Boys regardless of weight presented significantly higher levels of blood glucose and higher prevalence of IFG than girls. Obese boys were found more insulin resistant than obese girls. HOMA-IR thresholds of 3.6 for girls and 4.4 for boys were associated with increased cardiometabolic risks. For both genders, the model of HOMA-IR prediction was composed of age, BMI, ratio of free triiodthyronine to free thyroxine, gamma-glutamyltransferase activity and levels of triglycerides and sex hormone-binding globulin. The type 2 diabetes in adolescents, including those who were obese, was rarely diagnosed. Obese adolescent boys were at greater risk for IR and for IFG than obese girls. In adolescence, thresholds of HOMA-IR in contrast to predictors were found gender specific.

A short overview of new drugs approved for the treatment of obesity (lorcaserin, phentermine/topiramate combination) as well as those with a perspective for approval as antiobesity drugs (cetilistat, naltrexone/bupropion combination, liraglutide) is presented. All these drugs produce significant weight loss accompanied by reductions in cardiometabolic health risks. Although the adverse events were rather rare and tended to decrease with the duration of treatment with most of these medications, the drug-specific safety concerns should be seriously considered. In order to ensure an appropriate, efficient and safe implementation of novel antiobesity drugs into the comprehensive treatment of obesity, it will be necessary to establish a network of physicians and other health-care providers well educated in obesity management.

Worldwide obesity prevalence has nearly doubled since 1980. Due to numerous co-morbidities, obesity represents a serious health and socioeconomic problem worldwide. Pharmacotherapy should be an integral part of comprehensive obesity management. Drug therapy can assist in weight loss and its maintenance in those individuals who do not achieve appropriate weight loss through lifestyle interventions alone. After the withdrawal of sibutramine from the market in 2010, orlistat, a lipase inhibitor, was the only remaining prescription drug approved for the long-term treatment of obesity. In 2012, phentermine/topiramate extended-release (PHEN/TPM ER) combination and lorcaserin were approved by the US FDA as novel medications for long-term weight management. Three major phase III trials conducted with each drug confirmed their efficacy in terms of weight loss/maintenance and improvement of cardiometabolic risks. No head-to-head studies between the two new anti-obesity drugs have been carried out. However, in the existing studies PHEN/TPM ER had a superior weight loss profile to lorcaserin but the incidence of adverse effects was lower with lorcaserin. Both drugs were well-tolerated, and adverse events were modest in intensity, dose dependent, rather rare, and tended to decrease with the duration of treatment. Major safety concerns regarding PHEN/TPM ER include elevations in resting pulse rate, teratogenicity, mild metabolic acidosis, and psychiatric and cognitive adverse events. Valvulopathy, cognitive impairment, psychiatric disorders, and hypoglycemia represent major safety concerns for lorcaserin. Although existing trials have not demonstrated any significant issues with PHEN/TPM ER-induced heart rate elevation and lorcaserin-induced valvulopathy, all safety concerns should be seriously taken into account in patients treated with either of these novel anti-obesity medications.

Common obesity is a result of interaction between genes and environmental/lifestyle factors, with heritability estimates 40-70%. Not only the susceptibility to obesity but also the success of weight management depends on the genetic background of each individual. This paper summarizes the up-to-date knowledge on genetic causes of common obesities. Introduction of genome-wide association studies (GWAS) led to an identification of a total of 32 variants associated with obesity/BMI and 14 with body fat distribution. Further, a great progress in revealing the mechanisms regulating the energy balance was also noted. However, the proportion of explained variance for BMI is still low, suggesting other mechanisms such as gene-gene and gene-environment interactions, rare gene variants, copy number variants polymorphisms, or epigenetic modifications and microRNAs regulating gene transcription. In summary, we present results of our studies on obesity risk variants in Czech adults, children and adolescents including those evaluating the influence of selected gene variants on the outcomes of weight management.