The brain is the conductor: diet-induced inflammation overlapping physiological control of body mass and metabolism

Abstract

Obesity is currently a worldwide pandemic. It affects more than 300 million humans and it will probably increase over the next 20 years. The consumption of calorie-rich foods is responsible for most of the obesity cases, but not all humans exposed to high-calorie diets develop the disease. This fact has prompted researchers to investigate the mechanisms linking the consumption of high-calorie diets to the generation of an imbalance between energy intake and expenditure. According to recent studies, the exposure to fat-rich diets induces an inflammatory response in the hypothalamic areas involved in the control of feeding and thermogenesis. The inflammatory process damages the neuronal circuitries that maintain the homeostatic control of the body's energy stores, therefore favoring body mass gain. This review will focus on the main advances obtained in this field. Arq Bras Endocrinol Metab. 2009;53(2):151-158. KeywordsInflammation; hypothalamus; metabolism; weight control; fat-rich diet RESUMOObesidade é hoje um grave problema de saúde pública no mundo. Mais de 300 milhões de pessoas são obesas e esse número deve crescer substancialmente nos próximos 20 anos. As dietas ricas em calorias são a principal causa de obesidade, porém, nem todos os indivíduos expostos a dietas altamente calóricas se tornam obesos. Tal fato estimulou pesquisadores a investigarem os mecanismos que ligam o consumo de dietas ricas em calorias ao desenvolvimento de um balanço inadequado entre consumo e gasto energético. De acordo com estudos recentes, o consumo de dietas ricas em gorduras induz a ativação de uma resposta inflamatória nas áreas do hipotálamo envolvidas com o controle da fome e da termogênese. Tal processo inflamatório lesa os circuitos neuronais que mantêm o controle homeostático das reservas corporais de energia, favorecendo assim o ganho de massa adiposa. Esta revisão irá focar os principais avanços obtidos nesta área. Arq Bras Endocrinol Metab. 2009;53(2):151-158. Descritores

Design and development of a peptide-based adiponectin receptor agonist for cancer treatment

“…In addition, calorie-rich diet has been shown to induce inflammatory responses in microglia cells, which potentially can promote development of brain neoplasms [80,81]. …”

Changes in Brain Activity After a Diet‐Induced Obesity

“…Our study compared the brain metabolism of lean subjects vs. subjects submitted to 5 months of deleterious diet, i.e., the equivalent in humans of a well-established morbid obesity (14,15). In a recent review, Velloso (33) reminded that high-fat diets induce an inflammatory response in the hypothalamic areas involved in the control of feeding and thermogenesis. This inflammatory process would damage the neuronal circuitries that maintain the homeostatic control of the body's energy stores, therefore favoring body mass gain and obesity (33).…”

Obesity-mediated inflammation may damage the brain circuit that regulates food intake

“…These immune cells secrete several pro-inflammatory cytokines and chemokines that may block insulin signaling and recruit other macrophages, which may propagate the low-grade inflammation and lead to further insulin resistance (Olefsky and Glass, 2010). High-fat diet has been found in experimental animal models to induce an inflammatory response in the hypothalamic areas that control feeding behavior and energy homeostasis by regulating downstream neurons (Velloso, 2009). Hypothalamic inflammation may result in the breakdown of the circuitry that maintains balance between energy intake and energy expenditure.…”