RESUMO
Obesity is characterized by chronic and low-grade systemic inflammation, an increase of adipose tissue, hypertrophy, and hyperplasia of adipocytes. Adipose tissues can be classified into white, brown, beige and pink adipose tissues, which display different regulatory, morphological and functional characteristics of their adipocyte and immune cells. Brown and white adipocytes can play a key role not only in the control of energy homeostasis, or through the balance between energy storage and expenditure, but also by the modulation of immune and inflammatory responses. Therefore, brown and white adipocytes can orchestrate important immunological crosstalk that may deeply impact the tumor microenvironment and be crucial for cancer establishment and progression. Recent works have indicated that white adipose tissues can undergo a process called browning, in which an inducible brown adipocyte develops. In this review, we depict the mechanisms involved in the differential role of brown, white and pink adipocytes, highlighting their structural, morphological, regulatory and functional characteristics and correlation with cancer predisposition, establishment, and progression. We also discuss the impact of the increased adiposity in the inflammatory and immunological modulation. Moreover, we focused on the plasticity of adipocytes, describing the molecules produced and secreted by those cells, the modulation of the signaling pathways involved in the browning phenomena of white adipose tissue and its impact on inflammation and cancer.
Assuntos
Adiposidade/imunologia , Carcinogênese/imunologia , Inflamação/imunologia , Neoplasias/imunologia , Obesidade/imunologia , Adipócitos Marrons/imunologia , Adipócitos Marrons/metabolismo , Adipócitos Brancos/imunologia , Adipócitos Brancos/metabolismo , Tecido Adiposo Marrom/citologia , Tecido Adiposo Marrom/imunologia , Tecido Adiposo Marrom/metabolismo , Tecido Adiposo Branco/citologia , Tecido Adiposo Branco/imunologia , Tecido Adiposo Branco/metabolismo , Animais , Carcinogênese/patologia , Modelos Animais de Doenças , Progressão da Doença , Metabolismo Energético/imunologia , Humanos , Inflamação/metabolismo , Inflamação/patologia , Neoplasias/metabolismo , Neoplasias/patologia , Obesidade/complicações , Obesidade/metabolismo , Microambiente Tumoral/imunologiaRESUMO
Introducción: Evidencias sugieren que la testosterona interviene en la regulación del metabolismo de la glucosa y los lípidos.Objetivo: determinar la relación entre los niveles de testosterona y la sensibilidad a la insulina, la adiposidad y los parámetros del metabolismo lipídico en hombres.Métodos: estudio transversal y descriptivo en 225 hombres, entre 35 y 60 años, con y sin trastornos de la tolerancia a la glucosa. Se midieron: talla, peso, circunferencias de la cintura y de la cadera. Se realizaron determinaciones de insulina, glicemia, testosterona, colesterol, HDL-colesterol, LDL-colesterol y triglicéridos. Se determinaron índices de sensibilidad y resistencia a la insulina.Resultados: se encontró una correlación negativa entre los niveles de testosterona y la resistencia a la insulina, y los parámetros de adiposidad explorados (índice de masa corporal, circunferencias abdominal y de la cadera, índice cintura/cadera). El nivel de testosterona fue menor en los sujetos con hipertrigliceridemia. En los sujetos con trastornos de la tolerancia, se encontró un aumento significativo de la frecuencia de obesidad abdominal en presencia de valores bajos de testosterona.Conclusiones: existe una asociación directa entre los niveles de testosterona y la sensibilidad a la insulina en la población estudiada. La disminución de los niveles de testosterona en presencia de los desórdenes asociados al síndrome metabólico, sugiere la indicación de una evaluación metabólica temprana a los pacientes con hipogonadismo(AU)
Introduction: Evidence suggests that testosterone participates in the regulation of glucose and lipid metabolism.Objective: determine the relationship between testosterone levels and insulin sensitivity, adiposity and metabolism parameters in men.Methods: a descriptive cross-sectional study was conducted of 225 men aged 35-60 with and without glucose tolerance disorders. The variables measured were height, weight, and waist and hip circumference. Determinations were made for insulin, glycemia, testosterone, cholesterol, HDL cholesterol, LDL cholesterol and triglycerides. Insulin sensitivity and resistance were also determined.Results: a negative correlation was found between testosterone levels/insulin resistance and the adiposity parameters considered (body mass index, waist and hip circumference and waist to hip ratio). Testosterone levels were lower in subjects with hypertriglyceridemia. Patients with tolerance disorders showed a significant increase in the frequency of abdominal obesity in the presence of low testosterone values.Conclusions: a direct relationship was found between testosterone levels and insulin sensitivity in the population studied. Reduced testosterone levels in the presence of disorders associated to metabolic syndrome suggest the need for an early metabolic assessment of patients with hypogonadism(AU)
Assuntos
Humanos , Masculino , Testosterona/metabolismo , Resistência à Insulina/imunologia , Adiposidade/imunologia , Metabolismo dos Lipídeos/imunologia , Hipogonadismo/epidemiologia , Epidemiologia Descritiva , Estudos Transversais/métodosRESUMO
Gluten exclusion (protein complex present in many cereals) has been proposed as an option for the prevention of diseases other than coeliac disease. However, the effects of gluten-free diets on obesity and its mechanisms of action have not been studied. Thus, our objective was to assess whether gluten exclusion can prevent adipose tissue expansion and its consequences. C57BL/6 mice were fed a high-fat diet containing 4.5% gluten (Control) or no gluten (GF). Body weight and adiposity gains, leukocyte rolling and adhesion, macrophage infiltration and cytokine production in adipose tissue were assessed. Blood lipid profiles, glycaemia, insulin resistance and adipokines were measured. Expression of the PPAR-α and γ, lipoprotein lipase (LPL), hormone sensitive lipase (HSL), carnitine palmitoyl acyltransferase-1 (CPT-1), insulin receptor, GLUT-4 and adipokines were assessed in epidydimal fat. Gluten-free animals showed a reduction in body weight gain and adiposity, without changes in food intake or lipid excretion. These results were associated with up-regulation of PPAR-α, LPL, HSL and CPT-1, which are related to lipolysis and fatty acid oxidation. There was an improvement in glucose homeostasis and pro-inflammatory profile-related overexpression of PPAR-γ. Moreover, intravital microscopy showed a lower number of adhered cells in the adipose tissue microvasculature. The overexpression of PPAR-γ is related to the increase of adiponectin and GLUT-4. Our data support the beneficial effects of gluten-free diets in reducing adiposity gain, inflammation and insulin resistance. The data suggests that diet gluten exclusion should be tested as a new dietary approach to prevent the development of obesity and metabolic disorders.