Fabrication of a simple 3D-printed microfluidic device with embedded electrochemiluminescence detection for rapid determination of sibutramine in dietary supplements.

The design and fabrication of a simple 3D-printed platform with embedded electrochemiluminescence (ECL) detection for sibutramine determination is described. The microfluidic platform was fabricated by the fused deposition 3D-printing technique with polylactic acid filament, facilitated by computer-aided design (CAD). A three-electrode system was integrated into the device using graphene carbon paste as a working electrode, Ag/AgCl wire as a reference, and a graphite rod as a counter electrode. A further modification was carried out by applying bimetallic Au-Pt nanoparticle-supported multi-walled carbon nanotubes (MWCNT-Au-Pt) on the working electrode surface to enhance the electrocatalytic performance by exploiting the unique properties of nanomaterials. The analytical feasibility of the CAD-ECL sensor was tested through its application for the determination of sibutramine in dietary supplements. Under the optimized conditions, based on the enhancing effect of luminol emission, the device exhibited a linear calibration curve of the logarithmic sibutramine concentration versus ECL intensity in the range 5 × 10-3 to 1 ng mL-1. The limit of detection was 3 pg mL-1 with a relative standard deviation of 1.7% (n = 15). The 3D-printed prototype can be successfully applied to a small-scale analysis in a simple and cost-effective approach.

An Indonesian slimming drug with undeclared ingredients causing harm.

This paper reports the presence of undeclared drugs in the herbal slimming supplement Sulami®. The four cases of the adverse drug reactions related to Sulami® were reported to the Dutch Pharmacovigilance Centre (Lareb) or the Dutch Poisons Information Centre (DPIC). The analysis of all four collected samples revealed adulteration with sibutramine and canrenone. Both drugs can cause serious adverse drug reactions. From a legal point of view, it is clear that Sulami® does not meet the legal requirement for safety. As defined in the European General Food Law Regulation, food business operators are responsible for food safety. This also applies to online store owners who sell herbal preparations. Thus, it is clear that it is forbidden to sell Sulami® on the European and Dutch market. Collaboration between involved national authorities makes it possible to identify risky products. This allows the nationally responsible regulators to take targeted action. They can call on users to report sell points what makes it possible to arrest the sellers and confiscate the dangerous products. Beyond the national, also, the European enforcement organizations should take legal measures where possible, to protect public health. The Heads of Food Safety Agencies Working Group on Food Supplements "an Initiative on European level" is a good example of efforts to improve consumer safety.

Adulteration of Weight Loss Supplements by the Illegal Addition of Synthetic Pharmaceuticals.

Weight loss supplements that have illegal additives of pharmaceutical drugs or analogues have additional health risks, and customers may not be aware of what they are taking. This research is an essential investigation and quantification of illegally added pharmaceuticals or prescription medications, specifically fluoxetine, phenolphthalein, and sibutramine, in herbal weight loss supplements offered for sale in the United Arab Emirates (UAE). In this case, 137 weight loss supplements were collected and analyzed in this study. Reversed-phase high-performance liquid chromatography with UV absorption detection coupled to tandem mass spectrometry (RP-HPLC-MS/MS) analyses were used to determine the presence of the pharmaceutical chemicals. Among the weight loss supplements, 15.3% (95% CI: 9.2-21.4) contained undeclared sibutramine, 13.9% (95% CI: 8.01-19.7) contained undeclared phenolphthalein, and 5.1% (95% CI: 1.4-8.8) contained undeclared fluoxetine. Amongst all weight loss supplements, 17.5% (95% CI: 11.07-24) contained significant concentrations of either sibutramine, phenolphthalein, or fluoxetine. Whilst weight loss herbal supplements offered for sale in the UAE have relatively low percentages of undeclared pharmaceuticals, many people take several different supplements daily and may encounter quite high levels of combined exposure to toxic compounds.

Impact of timing of the anorexigen sibutramine administration on reproductive end-points of male rats.

Sibutramine is a non-selective serotonin-norepinephrine reuptake inhibitor orally administered for weight loss. In a previous study, we showed pharmacological mechanisms involved in the reduction of sperm quality and fertility of rats exposed for 30 days to this anorexigen in the light phase of the light-dark (l/d) cycle. It is already known that rodents are nightlife animals, with higher metabolic activity during the dark phase than in the light phase of the light-dark (l/d) cycle. Thus, the present study aimed to investigate whether the deleterious effects on reproductive parameters after sibutramine administration would be enhanced after a shorter period of exposure during the dark phase of the l/d cycle. For this, adult male Wistar rats were treated with sibutramine (10 mg/kg/d) or vehicle for 15 days during the dark phase of the l/d cycle. Sibutramine treatment decreased final body and reproductive organ weights, as well as serum testosterone levels. Sperm transit time through the epididymis was accelerated, and sperm concentration and motility were diminished in the sibutramine-exposed rats. The decrease in sperm concentration was also verified in the epididymal histological sections. In conclusion, the deleterious effects of sibutramine on reproductive parameters of male rats were enhanced when the exposure occurred in the dark phase of the l/d cycle, even after a short exposure duration. Our results reinforce the impact of timing on drug therapeutic action.

New insights into potential nutritional effects of dietary saponins in protecting against the development of obesity.

Excessive energy intake, poor physical exercise and genetics/epigenetics are instrumental for the development of obesity. Because of rapidly emerging evidences related to off-target effects and toxicity of anti-obesity drugs, there is a need to search for more effective and targeted drugs for treatment of obesity. Substantial studies have found the nutritional effects of dietary saponins (bio-detergents) in terms of decreasing the synthesis of lipids, suppressing adipogenesis, inhibiting intestinal absorption of lipids, and promoting fecal excretion of bile acids and triglycerides. Dietary saponin have been approved as potent pancreatic lipase inhibitors, disaccharidase enzyme inhibitors, antagonistic to in vitro lipogenesis and in vivo appetite suppressants, antioxidants, immune-regulators, prevent fatty liver formation, protects epithelial vasculature and regulate body weight. Many dietary saponins, such as sibutramine, morgoside, sessiloside, soysaponin B, and diosgenin, have treatment potential against the development of obesity. Excellent scientific achievements have been developed for a better understanding the mechanism of saponins in preventing obesity.

Effects of isolated or combined exposure to sibutramine and rosuvastatin on reproductive parameters of adult male rats.

Many obese patients are exposed to hypolipidemic and serotonin-norepinephrine reuptake inhibitor (SNRI) drugs. Statins are one of the most marketed drugs in the world to treat dyslipidemia, while sibutramine, a SNRI drug, is prescribed in some countries to treat obesity and is detected as an additive in many adulterated weight loss supplements marketed worldwide. Previous studies reported adverse effects of isolated exposure to these drugs on male rat reproductive parameters. In the present work, we further investigated male reproductive toxicity of these drugs, administered in isolation or combination in adult rats for a longer period of treatment. Adult male rats (90 days) were treated (gavage) for 70 days with saline and dimethyl sulfoxide (control), sibutramine (10 mg/kg), rosuvastatin (5 mg/kg), or rosuvastatin combined with sibutramine. Sibutramine alone or with rosuvastatin, promoted a reduction in food intake and body weight gain, weight of the epididymis, ventral prostate and seminal vesicle; as well as decreased sperm reserves and transit time through the epididymis; androgen depletion; and increased index of cytoplasmic droplet. The rosuvastatin-treated group showed reduced frequency of ejaculation. Exposure to this drug alone or combined with sibutramine impaired epididymal morphology. Co-exposed rats had altered epididymal morphometry, and seminal vesicle and testis weights. The rats also showed decreased fertility after natural mating and a trend toward a delay in ejaculation, suggesting a small synergistic effect of these drugs. Given the greater reproductive efficiency of rodents, the results obtained in the present study raise concern regarding possible fertility impairment in men taking statins and SNRI drugs.

[Development and validation of methodology of quantitative determination of sibutramine in dietary supplements by high performance liquid chromatography].

Sibutramine is a highly effective drug for the treatment of obesity. In this regard, unscrupulous manufacturers can add sibutramine as a biologically active synthetic substance prohibited for use in the composition of dietary supplements. Thus, the problem associated with the illegal circulation of such dietary supplements is especially actual, given the scale of the sale of these products. The development and validation of methods for the determination of sibutramine in dietary supplements for slimming (anorexigenic action) for the purpose of quality control in order to ensure the quality of dietary supplements when introduced into civil circulation at customs and on the market. The aim of the study - to develop a method for the quantitative determination of sibutramin in dietary supplements for weight loss by high performance liquid chromatography (HPLC) and to validate it. Material and methods. For the quantitative determination of sibutramine in dietary supplements, we used an Agilent 1100 high performance liquid chromatograph with a UV-detector. The stationary phase was a chromatographic column C18 NUCLEOSIL 4.6×150 mm, particle size 5 µm. The mobile phase contained 0.05 M formate buffer pH 4.0 and acetonitrile in a ratio of 40:60 (by volume). Results and discussion. A methodology has been developed for the determination of sibutramine in dietary supplements for weight loss, which makes it possible to control the quality of dietary supplements. Based on the obtained chromatograms, the specificity was determined; the plant components did not influence the determination of sibutramine in model mixtures. The suitability of the chromatographic system was determined: the retention factor of the compound - 2.222 (more than 2.0), N - 5776 theoretical plates (more than 5000), T peak of sibutramine - 0.939 (not more than 1.5). Within the analytical area of the linearity method: R2=0.9993 (over 0.9950). ε=0.46% (does not exceed 1.5%), the confidence interval includes the value of 100%, the calculated value of the Student's criterion tcalc (2.47) was less than the tabular ttable (2.80), which proved the correctness of the methodology. The precision of the results was determined by the obtained RSD value, which was 0.91% (less than 1%). Limit of detection (LOD) and limit of quantification (LOQ) took values of 0.1 and 1.0%, respectively. The range of measured concentrations was 0.01-20.0 mg/g. Conclusion. As a result of the studies, the method for sibutramine determination in dietary supplements with anorexigenic action was tested and can be used in quality control of dietary supplements.

Over-the-Counter Herbal Weight Loss Supplements in Egypt: Label Claim, Microbiological and Pharmaceutical Quality, and Safety Assessments.

OBJECTIVES: Nutraceuticals are advertised and sold with the label claim of being natural and safe herbal products. Due to the absence of clear regulations and guidelines for safety assessments of these products, nutraceuticals are commonly adulterated in order to increase sales. The objective of the current study was to design a comprehensive evaluation system to assess the safety, efficacy, authenticity according to label claim, and pharmaceutical quality of herbal slimming products in between 2015 and 2017. METHODS: We designed a comprehensive assessment system to evaluate the safety, authenticity according to label claim, and pharmaceutical quality of slimming nutraceuticals. Six different popular products were evaluated (Zotreem Plus®, Zotreem Extra®, Malaysian Super Slim®, AB Slim®, Chinese Super Slim®, and Metabolites®). The pharmaceutical evaluation included analyzing the samples via high-performance liquid chromatography to determine any possible adulterants. Additionally, the products' physical properties were assessed via pharmacopeial tests. Finally, a microbial evaluation and a cross-sectional observational retrospective prevalence study were conducted to assess the products' safety and efficacy. -Results: The tested products were found to be adulterated with unreported active pharmaceutical ingredients such as sibutramine, sildenafil, phenolphthalein, and orlistat. Furthermore, they contained heterogeneous amounts of adulterants and exhibited an unsatisfactory pharmaceutical and microbial quality. Finally, the observational survey conducted on users showed that high percentages of participants suffered from common side effects such as depression, diarrhea, and hypertension. CONCLUSIONS: These products threaten the health of consumers. There is a need to raise awareness of the lethal consequences of illegal nutraceuticals.

Isolation and structural characterization of a novel sibutramine analogue, chlorosipentramine, in a slimming dietary supplement, by using HPLC-PDA, LC-Q-TOF/MS, FT-IR, and NMR.

A novel sibutramine analogue was detected in a slimming formula by high performance liquid chromatography with a photo diode detector array (HPLC-PDA). The unknown compound exhibited an ultraviolet (UV) spectrum that was similar to that of chlorosibutramine, despite having a different HPLC retention time. Further analysis of the slimming formula by LC-quadrupole time-of-flight mass spectrometry (LC-Q-TOF/MS) showed that the unknown compound had the formula C18H27Cl2N. To elucidate the structure of this new sibutramine analogue, the target compound in the slimming formula was isolated on a preparative-LC system equipped with a PDA. After analysis by fourier transform infrared (FT-IR) and nuclear magnetic resonance (NMR) spectroscopy, the unknown compound was identified as a sibutramine analogue in which the iso-butyl group on the side chain is replaced with an iso-pentyl group. This new sibutramine analogue was identified to be 1-(1-(3,4-dichlorophenyl)cyclobutyl)-N,N,4-trimethylpentan-1-amine and has been named as chlorosipentramine.

A rapid ATR-FTIR spectroscopic method for detection of sibutramine adulteration in tea and coffee based on hierarchical cluster and principal component analyses.

Sibutramine may be illicitly included in herbal slimming foods and supplements marketed as "100% natural" to enhance weight loss. Considering public health and legal regulations, there is an urgent need for effective, rapid and reliable techniques to detect sibutramine in dietetic herbal foods, teas and dietary supplements. This research comprehensively explored, for the first time, detection of sibutramine in green tea, green coffee and mixed herbal tea using ATR-FTIR spectroscopic technique combined with chemometrics. Hierarchical cluster analysis and PCA principle component analysis techniques were employed in spectral range (2746-2656cm-1) for classification and discrimination through Euclidian distance and Ward's algorithm. Unadulterated and adulterated samples were classified and discriminated with respect to their sibutramine contents with perfect accuracy without any false prediction. The results suggest that existence of the active substance could be successfully determined at the levels in the range of 0.375-12mg in totally 1.75g of green tea, green coffee and mixed herbal tea by using FTIR-ATR technique combined with chemometrics.

Near Infrared Spectroscopy Detection and Quantification of Herbal Medicines Adulterated with Sibutramine.

There is an increasing demand for herbal medicines in weight loss treatment. Some synthetic chemicals, such as sibutramine (SB), have been detected as adulterants in herbal formulations. In this study, two strategies using near infrared (NIR) spectroscopy have been developed to evaluate potential adulteration of herbal medicines with SB: a qualitative screening approach and a quantitative methodology based on multivariate calibration. Samples were composed by products commercialized as herbal medicines, as well as by laboratory adulterated samples. Spectra were obtained in the range of 14,000-4000 per cm. Using PLS-DA, a correct classification of 100% was achieved for the external validation set. In the quantitative approach, the root mean squares error of prediction (RMSEP), for both PLS and MLR models, was 0.2% w/w. The results prove the potential of NIR spectroscopy and multivariate calibration in quantifying sibutramine in adulterated herbal medicines samples.

Evaluation of vibrational spectroscopic methods to identify and quantify multiple adulterants in herbal medicines.

To counter the growth of herbal medicines adulterated with pharmaceuticals crossing borders, rapid, inexpensive and non-destructive analytical techniques, that can handle complex matrices, are required. Since mid-infrared (MIR), near infrared (NIR) and Raman spectroscopic techniques meet these criteria, their performance in identifying adulterants in seized weightloss herbal medicines is definitively determined. Initially a validated high pressure liquid chromatography methodology was used for reference identification and quantification of the adulterants sibutramine H2O·HCl, fenfluramine HCl and phenolphthalein. Of 38 products, only sibutramine and phenolphthalein were detected by HPLC. The spectroscopic measurements showed Raman was ill-suited due to sample burning and emission while NIR lacked adulterant selectivity. Conversely, MIR demonstrated apt identification performance, which manifested as spectrally meaningful separation based on the presence and type of adulterant during principal component analysis (test set validated). Partial least squares regression models were constructed from the MIR training sets for sibutramine and phenolphthalein - both models fitted the training set data well. Average test set prediction errors were 0.8% for sibutramine and 2.2% for phenolphthalein over the respective concentration ranges of 1.7-11.7% and 0.9-34.4%. MIR is apposite for the screening of anorectic and laxative adulterants and is the most viable technique for wider adulterant screening in herbal medicines.

Active pharmaceutical ingredients detected in herbal food supplements for weight loss sampled on the Dutch market.

Herbal food supplements claiming to reduce weight may contain active pharmacological ingredients (APIs) that can be used for the treatment of overweight and obesity. The aim of this study was to determine whether herbal food supplements for weight loss on the Dutch market contain APIs with weight loss properties. Herbal food supplements intended for weight loss (n = 50) were sampled from August 2004 to May 2013. An HPLC-DAD-MS/MS method was used to screen for the presence of the APIs in herbal supplements. In 24 samples the APIs sibutramine, desmethylsibutramine (DMS), didesmethylsibutramine (DDMS), rimonabant, sildenafil and/or the laxative phenolphthalein were identified 41 times. The presence of these APIs was, however, not stated on the label. The potential pharmacological effects of the detected APIs were estimated using data from reported effective doses of approved drugs. Use of 20 of the 24 herbal food supplements may result in potential pharmacological effects. Furthermore, risk assessment of phenolphthalein, a suspected carcinogen and found to be present in 10 supplements, based on the margin of exposure (MOE) approach, resulted in MOE values of 96-30,000. MOE values lower than 10,000 (96-220) were calculated for the daily intake levels of four out of these 10 supplements in which phenolphthalein was found. However, taking into account that weight loss preparations may be used for only a few weeks or months rather than during a lifetime, MOE values may be two to three orders of magnitude higher. The current study shows that the use of food supplements with sibutramine, DMS, DDMS and/or phenolphthalein could result in pharmacological effects.

Detection of sibutramine in adulterated dietary supplements using attenuated total reflectance-infrared spectroscopy.

Sibutramine is one of the most occurring adulterants encountered in dietary supplements with slimming as indication. These adulterated dietary supplements often contain a herbal matrix. When customs intercept these kind of supplements it is almost impossible to discriminate between the legal products and the adulterated ones, due to misleading packaging. Therefore in most cases these products are confiscated and send to laboratories for analysis. This results inherently in the confiscation of legal, non-adulterated products. Therefore there is a need for easy to use equipment and techniques to perform an initial screening of samples. Attenuated total reflectance-infrared (ATR-IR) spectroscopy was evaluated for the detection of sibutramine in adulterated dietary supplements. Data interpretation was performed using different basic chemometric techniques. It was found that the use of ATR-IR combined with the k-Nearest Neighbours (k-NN) was able to detect all adulterated dietary supplements in an external test set and this with a minimum of false positive results. This means that a small amount of legal products will still be confiscated and analyzed in a laboratory to be found negative, but no adulterated samples will pass the initial ATR-IR screening.

Dose-to-dose variations with single packages of counterfeit medicines and adulterated dietary supplements as a potential source of false negatives and inaccurate health risk assessments.

In this report, we show three examples of how the variability in dose units in single packages of counterfeit medicines and adulterated dietary supplements may contribute to a false negative screening result and inaccurate health risk assessments. We describe a counterfeit Viagra 100mg blister pack and a box of an instant coffee both containing dose units with and without an active pharmaceutical ingredient (API). We also describe a purportedly herbal slimming product with capsules that mutually differed in API and impurities. The adulterated dietary supplements contained sibutramine, benzyl-sibutramine, N-desmethyl-sibutramine (DMS), N,N-didesmethyl-sibutramine (DDMS) and several other related impurities. Counterfeit medicines and adulterated dietary supplements are a health risk because their quality is unreliable. Health risks are even greater when such unreliability extends to fundamental differences between dose units in one package. Because dose-to-dose variability for these products is unpredictable, the confidence interval of a sample size is unknown. Consequently, the analyses of a selection of dose units may not be representative for the package. In the worst case, counterfeit or unauthorised medicines are not recognised as such or a health risk is not identified. In order to reduce erroneous results particular care should be taken when analysing a composite of dose units, when finding no API in a dietary supplement and when finding conformity in a suspect counterfeit medicine.

Screening for multiple weight loss and related drugs in dietary supplement materials by flow injection tandem mass spectrometry and their confirmation by liquid chromatography tandem mass spectrometry.

A new method has been developed using flow injection tandem mass spectrometry to semi-quantitatively screen for weight loss drugs, including sibutramine, N-desmethylsibutramine, N-didesmethylsibutramine, and phenolphthalein in dietary supplements. Positive identification of these drugs in samples was further confirmed and quantified by liquid chromatography tandem mass spectrometry. The degradation products of sibutramine were observed and identified by LC-MS/MS which include N-desmethylsibutramine, N-didesmethylsibutramine, N-formyldesmethylsibutramine, and N-formyldidesmethylsibutramine.

Potent inhibition of cytochrome P450 2B6 by sibutramine in human liver microsomes.

The present study was performed to evaluate the potency and specificity of sibutramine as an inhibitor of the activities of nine human CYP isoforms in liver microsomes. Using a cocktail assay, the effects of sibutramine on specific marker reactions of the nine CYP isoforms were measured in human liver microsomes. Sibutramine showed potent inhibition of CYP2B6-mediated bupropion 6-hydroxylation with an IC50 value of 1.61µM and Ki value of 0.466µM in a competitive manner at microsomal protein concentrations of 0.25mg/ml; this was 3.49-fold more potent than the typical CYP2B6 inhibitor thio-TEPA (Ki=1.59µM). In addition, sibutramine slightly inhibited CYP2C19 activity (Ki=16.6µM, noncompetitive inhibition) and CYP2D6 activity (Ki=15.7µM, noncompetitive inhibition). These observations indicated 35.6- and 33.7-fold decreases in inhibition potency, respectively, compared with that of CYP2B6 by sibutramine. However, no inhibition of CYP1A2, CYP2A6, CYP2C8, CYP2C9, CYP2D6, or CYP2E1 activities was observed. In addition, the CYP2B6 inhibitory potential of sibutramine was enhanced at a lower microsomal protein concentration of 0.05mg/ml. After 30min preincubation of human liver microsomes with sibutramine in the presence of NADPH, no shift in IC50 was observed in terms of inhibition of the activities of the nine CYPs, suggesting that sibutramine is not a time-dependent inactivator. These observations suggest that sibutramine is a selective and potent inhibitor of CYP2B6 in vitro, whereas inhibition of other CYPs is substantially lower. These in vitro data support the use of sibutramine as a well-known inhibitor of CYP2B6 for routine screening of P450 reversible inhibition when human liver microsomes are used as the enzyme source.

Determination of PDE-5 inhibitors and appetite suppressants in adulterated dietary supplements using LC/PDA and LC/MS.

There have been a number of reports of dietary supplements contaminated with illegal adulterants that threaten consumers' health because of their adverse pharmacological effects. In the present study, a convenient and economic method was developed to detect illegal pharmaceutics, such as PDE-5 inhibitor and appetite suppressants, using liquid chromatography (LC)/photodiode array (PDA) for screening and LC/mass spectrometry (MS) for successive confirmation. Target peaks were identified by comparison of their chromatographic retention times and PDA spectra with those of synthetic standards and finally confirmed by LC/MS. As a result, tadalafil, a PDE-5 inhibitor, and N-desmethylsibutramine, a derivative of sibutramine, were detected in various dietary supplements at concentrations of 13.5-21.9 mg and 3.0 mg per single dose, respectively. The present study will contribute to the development of an analytical method enabling rapid screening of a variety of health foods, and the result suggests that consumers should be aware of serious health risks related to these illegal compounds.

Chinese slimming capsules containing sibutramine sold over the Internet: a case series.

BACKGROUND: In recent years, the market for dietary supplements has grown. International products are readily available for purchase over the Internet. We report 17 cases of poisoning with a single product, said to be of purely herbal origin, that was bought over the Internet. A complete declaration of the ingredients was not available. METHODS: We performed a retrospective study of cases of poisoning documented by the Göttingen and Freiburg poison information centers from 2005 to 2008. In 4 cases, we were able to perform toxicological analyses of leftover capsules and urine samples. RESULTS: The manifestations of poisoning in the 17 documented cases included malaise, tachycardia, headache, agitation, arterial hypertension, nausea, vomiting, dyspnea, insomnia, left-sided chest pressure, elevated temperature, and, in two cases, psychosis after the substance was combined with atomoxetine and methylphenidate and with citalopram, olanzapine, and chlorprothixene. The frequency of cases rose markedly in the last year of the study. The toxicological analyses of all samples studied revealed sibutramine. The dose in each capsule was nearly twice the maximum daily dose sibutramine in the medication containing this substance that is licensed for use in Germany. CONCLUSIONS: Products available without a prescription whose contents are claimed to be purely herbal may nonetheless contain synthetic substances in concentrations far above the therapeutic range and may be a cause of poisoning. When taking the history of a patient possibly suffering from an intoxication, the physician should ask specifically about drugs, dietary supplements, and so-called lifestyle products that were obtained without a prescription. It would be desirable for the contents of all such products to be declared, as required by law, so that their suitability for the market can be checked.

Hypothalamic regulation of food intake and clinical therapeutic applications: [review] / Regulação hipotalâmica da ingestão alimentar e suas aplicações terapêuticas clínicas: [revisão]

Current estimates suggest that over 1 billion people are overweight and over 300 million people are obese. Weight gain is due to an imbalance between energy expenditure and dietary intake. This review discusses the hypothalamic control of appetite and highlights key developments in research that have furthered our understanding of the complex pathways involved. Nuclei within the hypothalamus integrate peripheral signals such as adiposity and caloric intake to regulate important pathways within the central nervous system controlling food intake and energy expenditure. Firmly established pathways involve the orexigenic NPY/AgRP and the anorexigenic POMC/CART neurons in the arcuate nucleus (ARC) of the hypothalamus. These project from the ARC to other important hypothalamic nuclei, including the paraventricular, dorsomedial, ventromedial and lateral hypothalamic nuclei. In addition there are many projections to and from the brainstem, cortical areas and reward pathways, which modulate food intake.

As estimativas atuais sugerem que mais de 1 bilhão de pessoas apresentam sobrepeso e 300 milhões são obesas. O ganho de peso representa um desequilíbrio entre o gasto energético e o consumo alimentar. Esta revisão discute o controle hipotalâmico do apetite e destaca os pontos-chave no desenvolvimento de pesquisas para ampliar o nosso entendimento dos complexos mecanismos envolvidos nesta regulação. Núcleos situados no hipotálamo integram uma série de sinais com o sistema nervoso central controlando a ingestão alimentar e o gasto energético. As vias mais estabelecidas envolvem os neurônios orexigênicos NPY/AgRP e os neurônios anorexigênicos POMC/CART no núcleo arqueado (ARC) do hipotálamo. Esses neurônios se projetam do ARC para outros importantes núcleos hipotalâmicos, tais quais: paraventricular, dorsomedial, ventromedial e lateral. Além disso, existem várias projeções que vão e vem do tronco cerebral, das áreas corticais e das vias de retroalimentação que modulam o consumo alimentar.