title: The role of I-FABP as a biomarker of intestinal barrier dysfunction driven by gut microbiota changes in obesity.
abstract: BACKGROUND
  Intestinal fatty-acid binding protein (I-FABP) is expressed in epithelial cells of the mucosal layer of the small intestine tissue. When intestinal mucosal damage occurs, I-FABP is released into the circulation and its plasma concentration increases. In the context of obesity, the gut barrier integrity can be disrupted by dietary fat while intestinal permeability increases.
  
  
  OBJECTIVE
  To investigate whether intestinal fatty acid binding protein (I-FABP) is a suitable plasma marker of intestinal injury and inflammation in obesity.
  
  
  METHODS
  Twelve male Wistar rats were randomly divided into two groups of six animals each: standard (St) and high-fat (HF) diet fed groups for 12 weeks.
  
  
  RESULTS
  HF fed animals developed obesity, insulin resistance and seemed to present increased plasma levels of proinflammatory cytokines (MCP-1 and IL1β). The gut microbiota composition of these animals was also altered, with lower number of copies of Bacteroidetes, Prevotella spp. and Lactobacillus spp., in comparison with those from St diet group. Fecal lipopolysaccharide (LPS) concentrations tended to be increased in HF fed animals. Intestinal expression of TLR4 seemed to be also increased in HF fed animals suggesting that HF diet-induced dysbiosis may be behind the systemic inflammation observed. However, in contrast to other intestinal inflammatory diseases, plasma I-FABP levels were decreased in HF fed rats whereas I-FABP expression in jejunum tended to be increased.
  
  
  CONCLUSIONS
  HF diet-induced obesity is characterized by dysbiosis, insulin resistance and systemic inflammation. In this context, plasmatic I-FABP should not be used as a marker of the intestinal barrier dysfunction and the low-grade chronic inflammatory status.
authors.affiliation: Serviço de Endocrinologia, Diabetes e Metabolismo, Centro Hospitalar São João, Porto, Portugal.|Instituto de Investigação e Inovação em Saúde, Porto, Portugal.|Departamento de Bioquímica, Faculdade de Medicina, Universidade do Porto, Porto, Portugal.
authors.forename: Eva
authors.initials: E
authors.lastname: Lau
authors.affiliation: Departamento de Bioquímica, Faculdade de Medicina, Universidade do Porto, Porto, Portugal.|CINTESIS, Centro de Investigação em Tecnologias e Serviços de Saúde, Porto, Portugal.
authors.forename: Cláudia
authors.initials: C
authors.lastname: Marques
authors.affiliation: Departamento de Bioquímica, Faculdade de Medicina, Universidade do Porto, Porto, Portugal.|CINTESIS, Centro de Investigação em Tecnologias e Serviços de Saúde, Porto, Portugal.
authors.forename: Diogo
authors.initials: D
authors.lastname: Pestana
authors.affiliation: Departamento de Bioquímica, Faculdade de Medicina, Universidade do Porto, Porto, Portugal.
authors.forename: Mariana
authors.initials: M
authors.lastname: Santoalha
authors.affiliation: Serviço de Endocrinologia, Diabetes e Metabolismo, Centro Hospitalar São João, Porto, Portugal.|Instituto de Investigação e Inovação em Saúde, Porto, Portugal.|Departamento de Medicina, Faculdade de Medicina, Universidade do Porto, Porto, Portugal.
authors.forename: Davide
authors.initials: D
authors.lastname: Carvalho
authors.affiliation: Serviço de Endocrinologia, Diabetes e Metabolismo, Centro Hospitalar São João, Porto, Portugal.|Instituto de Investigação e Inovação em Saúde, Porto, Portugal.|Departamento de Medicina, Faculdade de Medicina, Universidade do Porto, Porto, Portugal.
authors.forename: Paula
authors.initials: P
authors.lastname: Freitas
authors.affiliation: Departamento de Bioquímica, Faculdade de Medicina, Universidade do Porto, Porto, Portugal.|CINTESIS, Centro de Investigação em Tecnologias e Serviços de Saúde, Porto, Portugal.|Nutrição e Metabolismo, NOVA Medical School|Faculdade de Ciências Médicas, Universidade NOVA de Lisboa, Lisboa, Portugal.
authors.forename: Conceição
authors.initials: C
authors.lastname: Calhau
keywords: Gut microbiota; Inflammation; Intestinal fatty acid binding protein; Intestinal permeability; Obesity