RESUMO
Given the increasing worldwide prevalence of obesity and associated metabolic disturbances, novel therapeutic strategies are imperatively required. A plausible manner to increase energy expenditure is the enhancement of thermogenic pathways in white (WAT) and brown adipose tissue (BAT). In the last 15 years, the identification of novel endogenous mechanisms to promote BAT activity or browning of WAT has pointed at gut microbiota as an important modulator of host metabolic homeostasis and energy balance. In this review, we focused on the relationship between gut microbiota composition and adipose tissue thermogenic program (including BAT activity and browning of WAT) in both physiological and stress conditions. Specifically, we reviewed the effects of fasting, caloric restriction, cold stress and metabolic endotoxemia on both browning and gut microbiota shifts. Mechanistically speaking, processes related to bile acid metabolism and the endocannabinoid system seem to play an important role. In summary, the gut microbiota seems to impact WAT and BAT physiology at multiple levels.
Assuntos
Tecido Adiposo Marrom/microbiologia , Tecido Adiposo Branco/microbiologia , Microbioma Gastrointestinal/fisiologia , Animais , Ácidos e Sais Biliares/metabolismo , Restrição Calórica , Jejum , Microbioma Gastrointestinal/genética , HumanosRESUMO
A two by two experimental study has been designed to determine the effect of gut microbiota on energy metabolism in mouse models. The metabolic phenotype of germ-free (GF, n = 20) and conventional (n = 20) mice was characterized using a NMR spectroscopy-based metabolic profiling approach, with a focus on sexual dimorphism (20 males, 20 females) and energy metabolism in urine, plasma, liver, and brown adipose tissue (BAT). Physiological data of age-matched GF and conventional mice showed that male animals had a higher weight than females in both groups. In addition, conventional males had a significantly higher total body fat content (TBFC) compared to conventional females, whereas this sexual dimorphism disappeared in GF animals (i.e., male GF mice had a TBFC similar to those of conventional and GF females). Profiling of BAT hydrophilic extracts revealed that sexual dimorphism in normal mice was absent in GF animals, which also displayed lower BAT lactate levels and higher levels of (D)-3-hydroxybutyrate in liver, plasma, and BAT, together with lower circulating levels of VLDL. These data indicate that the gut microbiota modulate the lipid metabolism in BAT, as the absence of gut microbiota stimulated both hepatic and BAT lipolysis while inhibiting lipogenesis. We also demonstrated that (1)H NMR metabolic profiles of BAT were excellent predictors of BW and TBFC, indicating the potential of BAT to fight against obesity.
Assuntos
Tecido Adiposo Marrom/metabolismo , Tecido Adiposo Marrom/microbiologia , Metabolismo dos Lipídeos , Metaboloma/fisiologia , Metagenoma/fisiologia , Ácido 3-Hidroxibutírico/análise , Ácido 3-Hidroxibutírico/sangue , Tecido Adiposo/metabolismo , Animais , Peso Corporal/fisiologia , Análise Discriminante , Feminino , Trato Gastrointestinal/microbiologia , Vida Livre de Germes , Análise dos Mínimos Quadrados , Fígado/metabolismo , Masculino , Camundongos , Ressonância Magnética Nuclear Biomolecular , Caracteres Sexuais , Simbiose/fisiologia , Urina/químicaAssuntos
Imunofluorescência , Vírus da Raiva/isolamento & purificação , Raiva/etiologia , Tecido Adiposo Marrom/microbiologia , Administração Oral , Glândulas Suprarrenais/microbiologia , Animais , Antígenos Virais/análise , Encéfalo/microbiologia , Cerebelo/microbiologia , Córnea/microbiologia , Cricetinae , Cabelo/microbiologia , Intestinos/microbiologia , Camundongos , Mucosa/microbiologia , Tecido Nervoso/microbiologia , Neurônios/microbiologia , Raiva/imunologia , Raiva/patologia , Retina/microbiologia , Glândulas Salivares/microbiologia , Pele/microbiologia , Bexiga Urinária/microbiologiaAssuntos
Vírus da Raiva/patogenicidade , Roedores , Tecido Adiposo Marrom/microbiologia , Administração Intranasal , Administração Oral , Animais , Sangue/microbiologia , Encéfalo/microbiologia , Imunofluorescência , Injeções , Injeções Intramusculares , Rim/microbiologia , Pulmão/microbiologia , Camundongos , Músculos/microbiologia , Vírus da Raiva/isolamento & purificação , Glândulas Salivares/microbiologia , Medula Espinal/microbiologia , Baço/microbiologia , Fatores de TempoAssuntos
Adaptação Biológica , Animais de Laboratório , Camundongos/imunologia , Vírus da Raiva/crescimento & desenvolvimento , Raiva/veterinária , Doenças dos Roedores/microbiologia , Tecido Adiposo Marrom/microbiologia , Animais , Encéfalo/imunologia , Encéfalo/microbiologia , Cricetinae , Imunofluorescência , Raposas , Cavalos , Soros Imunes , Testes de Neutralização , Coelhos , Raiva/microbiologia , Vírus da Raiva/imunologia , Vírus da Raiva/isolamento & purificação , Vírus da Raiva/patogenicidade , Roedores , Glândulas Salivares/microbiologia , Especificidade da EspécieAssuntos
Vírus da Encefalite Transmitidos por Carrapatos/patogenicidade , Tecido Adiposo Marrom/microbiologia , Animais , Encéfalo/microbiologia , Encefalite Transmitida por Carrapatos/microbiologia , Intestinos/microbiologia , Fígado/microbiologia , Linfonodos/microbiologia , Camundongos , Medula Espinal/microbiologia , Baço/microbiologia , VirulênciaRESUMO
Cytomegalovirus infection of laboratory rats resulted in the appearance of virus and viral antigens in interscapular and periaortic brown fat. This appearance was limited to acute infection (first week post-infection) and was dependent on the route of inoculation. In our study virus could only be detected in subcutaneous brown fat in young rats (till 4 weeks of age), whereas in the deep brown fat (periaortic region) no age dependency was found.