RESUMEN
Obesity is currently a pandemic of worldwide proportions affecting millions of people. Recent studies have proposed the hypothesis that mechanisms not directly related to the human genome could be involved in the genesis of obesity, due to the fact that, when a population undergoes the same nutritional stress, not all individuals present weight gain related to the diet or become hyperglycemic. The human intestine is colonized by millions of bacteria which form the intestinal flora, known as gut flora. Studies show that lean and overweight human may present a difference in the composition of their intestinal flora; these studies suggest that the intestinal flora could be involved in the development of obesity. Several mechanisms explain the correlation between intestinal flora and obesity. The intestinal flora would increase the energetic extraction of non-digestible polysaccharides. In addition, the lipopolysaccharide from intestinal flora bacteria could trigger a chronic sub-clinical inflammatory process, leading to obesity and diabetes. Another mechanism through which the intestinal flora could lead to obesity would be through the regulation of genes of the host involved in energy storage and expenditure. In the past five years data coming from different sources established causal effects between intestinal microbiota and obesity/insulin resistance, and it is clear that this area will open new avenues of therapeutic to obesity, insulin resistance and DM2.
Asunto(s)
Microbioma Gastrointestinal/genética , Obesidad/microbiología , Investigación Biomédica Traslacional , Animales , Diabetes Mellitus Tipo 2/microbiología , Metabolismo Energético , Humanos , Inflamación/microbiología , Ratones , Obesidad/terapiaRESUMEN
Obesity is currently a pandemic of worldwide proportions affecting millions of people. Recent studies have proposed the hypothesis that mechanisms not directly related to the human genome could be involved in the genesis of obesity, due to the fact that, when a population undergoes the same nutritional stress, not all individuals present weight gain related to the diet or become hyperglycemic. The human intestine is colonized by millions of bacteria which form the intestinal flora, known as gut flora. Studies show that lean and overweight human may present a difference in the composition of their intestinal flora; these studies suggest that the intestinal flora could be involved in the development of obesity. Several mechanisms explain the correlation between intestinal flora and obesity. The intestinal flora would increase the energetic extraction of non-digestible polysaccharides. In addition, the lipopolysaccharide from intestinal flora bacteria could trigger a chronic sub-clinical inflammatory process, leading to obesity and diabetes. Another mechanism through which the intestinal flora could lead to obesity would be through the regulation of genes of the host involved in energy storage and expenditure. In the past five years data coming from different sources established causal effects between intestinal microbiota and obesity/insulin resistance, and it is clear that this area will open new avenues of therapeutic to obesity, insulin resistance and DM2.
Asunto(s)
Animales , Humanos , Ratones , Microbioma Gastrointestinal/genética , Obesidad/microbiología , Investigación Biomédica Traslacional , /microbiología , Metabolismo Energético , Inflamación/microbiología , Obesidad/terapiaRESUMEN
Autoimmune encephalitis has been a subject of research in the past few years; most of the cases are non-paraneoplastic and associated with an antibody to a surface protein of neurons. Studies have shown that VGKC complex is indeed represented by three proteins, and LGI1 is the most prevalent in limbic encephalitis. This entity is characterized by monophasic presentation with acute or subacute onset, memory loss, confusion, seizures and psychiatric symptoms. The presentation of anti-LGI1 antibodies in serum or CSF confirms the diagnosis. The treatment consists of immunotherapy with good clinical response, which is a criterion for diagnosis. We report a case of a patient with diagnosis confirmed six months after the symptoms onset, improvement after immunotherapy, but with episodes of relapse.
A encefalite autoimune tem sido assunto de pesquisa nos últimos anos, a maioria dos casos é não paraneoplásica e associada ao anticorpo para uma proteína de superfície dos neurônios. Estudos têm mostrado que o complexo VGKC é efetivamente representado por três proteínas, e a LGI1 é a mais prevalente na encefalite límbica. Essa entidade é caracterizada por apresentação monofásica com início agudo ou subagudo, perda de memória, confusão mental, crises convulsivas e sintomas psiquiátricos. A apresentação de anticorpos anti-LGI1 no soro ou no LCE confirma o diagnóstico. O tratamento consiste em imunoterapia com boa resposta clínica, que é um critério diagnóstico. Relatamos o caso de um paciente com diagnóstico confirmado seis meses após o início dos sintomas, com melhora após imunoterapia, porém com episódios de recaídas.
La encefalitis autoinmune ha sido asunto de investigación en los últimos años; la mayoría de los casos es no paraneoplásica y asociada al anticuerpo para una proteína de superficie de las neuronas. Estudios han mostrado que el complejo VGKC es efectivamente representado por tres proteínas, y la LGI1 es la más prevalente en la encefalitis límbica. Esa entidad es caracterizada por presentación monofásica con inicio agudo o subagudo, pérdida de memoria, confusión mental, crisis convulsivas y síntomas psiquiátricos. La presentación de anticuerpos anti-LGI1 en el suero o en el LCE confirma el diagnóstico. El tratamiento consiste en inmunoterapia con buena respuesta clínica, que es un criterio diagnóstico. Relatamos el caso de un paciente con diagnóstico confirmado seis meses después del inicio de los síntomas, con mejora después de inmunoterapia, aunque con episodios de recaídas.
Asunto(s)
Humanos , Encefalitis/inmunología , Inmunoterapia , Encefalitis LímbicaRESUMEN
BACKGROUND: Wound healing is impaired in diabetes mellitus, but the mechanisms involved in this process are virtually unknown. Proteins belonging to the insulin signaling pathway respond to insulin in the skin of rats. OBJECTIVE: The purpose of this study was to investigate the regulation of the insulin signaling pathway in wound healing and skin repair of normal and diabetic rats, and, in parallel, the effect of a topical insulin cream on wound healing and on the activation of this pathway. RESEARCH DESIGN AND METHODS: We investigated insulin signaling by immunoblotting during wound healing of control and diabetic animals with or without topical insulin. Diabetic patients with ulcers were randomized to receive topical insulin or placebo in a prospective, double-blind and placebo-controlled, randomized clinical trial (NCT 01295177) of wound healing. RESULTS AND CONCLUSIONS: Expression of IR, IRS-1, IRS-2, SHC, ERK, and AKT are increased in the tissue of healing wounds compared to intact skin, suggesting that the insulin signaling pathway may have an important role in this process. These pathways were attenuated in the wounded skin of diabetic rats, in parallel with an increase in the time of complete wound healing. Upon topical application of insulin cream, the wound healing time of diabetic animals was normalized, followed by a reversal of defective insulin signal transduction. In addition, the treatment also increased expression of other proteins, such as eNOS (also in bone marrow), VEGF, and SDF-1α in wounded skin. In diabetic patients, topical insulin cream markedly improved wound healing, representing an attractive and cost-free method for treating this devastating complication of diabetes. TRIAL REGISTRATION: ClinicalTrials.gov NCT01295177.
Asunto(s)
Complicaciones de la Diabetes/tratamiento farmacológico , Quinasas MAP Reguladas por Señal Extracelular/metabolismo , Insulina/administración & dosificación , Proteínas Proto-Oncogénicas c-akt/metabolismo , Transducción de Señal/efectos de los fármacos , Cicatrización de Heridas/efectos de los fármacos , Administración Tópica , Anciano , Animales , Médula Ósea/metabolismo , Quimiocina CXCL12/metabolismo , Cromonas/farmacología , Complicaciones de la Diabetes/metabolismo , Diabetes Mellitus Experimental/metabolismo , Femenino , Humanos , Masculino , Persona de Mediana Edad , Morfolinas/farmacología , Óxido Nítrico Sintasa de Tipo III/metabolismo , Inhibidores de las Quinasa Fosfoinosítidos-3 , Ratas , Ratas Wistar , Piel/efectos de los fármacos , Piel/metabolismo , Piel/patología , Factor A de Crecimiento Endotelial Vascular/metabolismoRESUMEN
Obesity is a pandemic which has been rapidly developing for three decades. When a population is submitted to the same nutritional stress, some individuals are less susceptible to diet-induced weight gain and hyperglycemia. This observation suggests that other mechanisms are involved which are not directly related to the human genome. The human gut contains an immense number of microorganisms, collectively known as the microbiota. Evidence that gut microbiota composition can differ between obese and lean humans has led to the speculation that gut microbiota can participate in the pathophysiology of obesity. Different mechanisms have been proposed to explain the link between gut flora and obesity. The first mechanism consists in the role of the gut microbiota to increase energy extraction from indigestible dietary polysaccharides. The second, consists in the role of gut flora to modulate plasma lipopolysaccharide levels which triggers chronic low-grade inflammation leading to obesity and diabetes. A third mechanism proposes that gut microbiota may induce regulation of host genes that modulate how energy is expended and stored. However, further studies are needed to clarify a number of issues related to the relationship between the gut microbiota and obesity.
Asunto(s)
Fenómenos Fisiológicos Bacterianos , Intestinos/microbiología , Metagenoma , Obesidad/microbiología , Animales , Grasas de la Dieta/administración & dosificación , Ingestión de Energía , Metabolismo Energético , Humanos , Mucosa Intestinal/metabolismo , Lipopolisacáridos/metabolismo , Obesidad/etiología , Obesidad/fisiopatología , Obesidad/terapia , Polisacáridos/química , Investigación Biomédica TraslacionalRESUMEN
Obesity is a pandemic which has been rapidly developing for three decades. When a population is submitted to the same nutritional stress, some individuals are less susceptible to diet-induced weight gain and hyperglycemia. This observation suggests that other mechanisms are involved which are not directly related to the human genome. The human gut contains an immense number of microorganisms, collectively known as the microbiota. Evidence that gut microbiota composition can differ between obese and lean humans has led to the speculation that gut microbiota can participate in the pathophysiology of obesity. Different mechanisms have been proposed to explain the link between gut flora and obesity. The first mechanism consists in the role of the gut microbiota to increase energy extraction from indigestible dietary polysaccharides. The second, consists in the role of gut flora to modulate plasma lipopolysaccharide levels which triggers chronic low-grade inflammation leading to obesity and diabetes. A third mechanism proposes that gut microbiota may induce regulation of host genes that modulate how energy is expended and stored. However, further studies are needed to clarify a number of issues related to the relationship between the gut microbiota and obesity.
A obesidade é uma pandemia que afeta milhões de pessoas em todo o mundo. Quando uma população é submetida ao mesmo estresse nutricional, alguns indivíduos são menos suscetíveis ao ganho de peso induzido pela dieta e à hiperglicemia. Essa observação sugere que outros mecanismos não diretamente relacionados ao genoma humano estejam envolvidos. O intestino humano é colonizado por milhões de bactérias, que coletivamente constituem a flora comensal normal. A evidência de que a composição da flora intestinal pode ser diferente em humanos magros e obesos levou à especulação de que a flora intestinal pode participar na fisiopatologia da obesidade. Diferentes mecanismos foram propostos para tentar explicar a correlação entre flora intestinal e obesidade. O primeiro mecanismo consiste no papel da flora intestinal na extração de energia de polissacarídeos não digeríveis. O segundo mecanismo envolve a modulação dos níveis de lipopolissacarídeo pela flora intestinal, o que desencadeia uma inflamação crônica subclínica que acarreta obesidade e diabetes. Um terceiro mecanismo propõe que a flora intestinal pode induzir a regulação de genes do hospedeiro que modulam como a energia é gasta e armazenada. Entretanto, estudos adicionais são necessários para estabelecer o papel da flora intestinal no desenvolvimento da obesidade.
Asunto(s)
Animales , Humanos , Fenómenos Fisiológicos Bacterianos , Intestinos/microbiología , Metagenoma , Obesidad/microbiología , Grasas de la Dieta/administración & dosificación , Ingestión de Energía , Metabolismo Energético , Intestinos/metabolismo , Lipopolisacáridos/metabolismo , Obesidad/etiología , Obesidad/fisiopatología , Obesidad/terapia , Polisacáridos/química , Investigación Biomédica TraslacionalRESUMEN
In animal models of diet-induced obesity, the activation of an inflammatory response in the hypothalamus produces molecular and functional resistance to the anorexigenic hormones insulin and leptin. The primary events triggered by dietary fats that ultimately lead to hypothalamic cytokine expression and inflammatory signaling are unknown. Here, we test the hypothesis that dietary fats act through the activation of toll-like receptors 2/4 and endoplasmic reticulum stress to induce cytokine expression in the hypothalamus of rodents. According to our results, long-chain saturated fatty acids activate predominantly toll-like receptor 4 signaling, which determines not only the induction of local cytokine expression but also promotes endoplasmic reticulum stress. Rats fed on a monounsaturated fat-rich diet do not develop hypothalamic leptin resistance, whereas toll-like receptor 4 loss-of-function mutation and immunopharmacological inhibition of toll-like receptor 4 protects mice from diet-induced obesity. Thus, toll-like receptor 4 acts as a predominant molecular target for saturated fatty acids in the hypothalamus, triggering the intracellular signaling network that induces an inflammatory response, and determines the resistance to anorexigenic signals.
Asunto(s)
Citocinas/metabolismo , Ácidos Grasos/administración & dosificación , Hipotálamo/metabolismo , Obesidad/inducido químicamente , Obesidad/patología , Transducción de Señal/efectos de los fármacos , Receptor Toll-Like 4/metabolismo , Animales , Anticuerpos/administración & dosificación , Peso Corporal/efectos de los fármacos , Citocinas/clasificación , Citocinas/genética , Modelos Animales de Enfermedad , Regulación de la Expresión Génica/efectos de los fármacos , Regulación de la Expresión Génica/fisiología , Hipotálamo/efectos de los fármacos , Inmunoprecipitación , Indoles , Masculino , Ratones , Ratones Endogámicos C3H , Ratones Mutantes , Microglía/efectos de los fármacos , Mutación , Obesidad/inmunología , Obesidad/metabolismo , ARN Mensajero/metabolismo , Ratas , Ratas Wistar , Receptor Toll-Like 2/inmunología , Receptor Toll-Like 4/genética , Receptor Toll-Like 4/inmunologíaRESUMEN
The aims of the present study were to investigate the expression of toll-like receptor 2 (TLR2) in muscle and white adipose tissue (WAT) of diet-induced obesity (DIO) mice, and also the effects of its inhibition, with the use of TLR2 antisense oligonucleotide (ASON), on insulin sensitivity and signaling. The expression of TLR2 was increased in muscle and WAT of DIO mice, compared with those that received standard chow. Inhibition of TLR2 in DIO mice, by TLR2 ASON, improved insulin sensitivity and signaling in muscle and WAT. In addition, data show that the inhibition of TLR2 expression prevents the activation of IKBKB, MAPK8, and serine phosphorylation of IRS1 in DIO mice, suggesting that TLR2 is a key modulator of the crosstalk between inflammatory and metabolic pathways. We, therefore, suggest that a selective interference with TLR2 presents an attractive opportunity for the treatment of insulin resistance in obesity and type 2 diabetes.
Asunto(s)
Tejido Adiposo Blanco/metabolismo , Grasas de la Dieta/farmacología , Expresión Génica/efectos de los fármacos , Músculo Esquelético/efectos de los fármacos , Músculo Esquelético/metabolismo , Oligodesoxirribonucleótidos Antisentido/farmacología , Transducción de Señal/efectos de los fármacos , Receptor Toll-Like 2/antagonistas & inhibidores , Tejido Adiposo Blanco/efectos de los fármacos , Animales , Glucemia/efectos de los fármacos , Immunoblotting , Inmunoprecipitación , Insulina/sangre , Resistencia a la Insulina , Masculino , RatonesRESUMEN
Obesity is associated with insulin resistance and a state of abnormal inflammatory response. The Toll-like receptor (TLR)4 has an important role in inflammation and immunity, and its expression has been reported in most tissues of the body, including the insulin-sensitive ones. Because it is activated by lipopolysaccharide and saturated fatty acids, which are inducers of insulin resistance, TLR4 may be a candidate for participation in the cross-talk between inflammatory and metabolic signals. Here, we show that C3H/HeJ mice, which have a loss-of-function mutation in TLR4, are protected against the development of diet-induced obesity. In addition, these mice demonstrate decreased adiposity, increased oxygen consumption, a decreased respiratory exchange ratio, improved insulin sensitivity, and enhanced insulin-signaling capacity in adipose tissue, muscle, and liver compared with control mice during high-fat feeding. Moreover, in these tissues, control mice fed a high-fat diet show an increase in IkappaB kinase complex and c-Jun NH(2)-terminal kinase activity, which is prevented in C3H/HeJ mice. In isolated muscles from C3H/HeJ mice, protection from saturated fatty acid-induced insulin resistance is observed. Thus, TLR4 appears to be an important mediator of obesity and insulin resistance and a potential target for the therapy of these highly prevalent medical conditions.