Macrophage Infiltration in Human Adipose Tissue
Condition: Obesity; Diabetes
MeSH terms: Obesity
Study type: Observational

Summary: 
      Quantification of macrophage infiltration and characterization of macrophage phenotype in
      adipose tissue of 60 obese subjects and 20 non obese subjects
    

Detailed description: 
      Obesity results from a disequilibrium in energy balance and an inability to adapt to
      lifestyles which encourage increased energy intake and sedentariness. These last years,
      numerous studies contributed to show that obesity is the pathology of an organ, the white
      adipose tissue (AT), characterized by a low grade inflammation when it is enlarged. The fact
      that adipocytes secrete a number of inflammatory factors or "adipokines" has forced several
      groups to reassess the involvement of the AT in wide range of physiological and
      pathophysiological processes. Adipose tissue probably contributes to the links between
      obesity, inflammation and insulin-resistance. Our previous results based on transcriptomics
      studies, showed that genes encoding inflammatory molecules are mobilized in adipose tissue of
      obese subjects and that caloric restriction improves greatly inflammatory profile. Our
      preliminary studies on the morphology of adipose tissue lead us to observe a major
      infiltration of macrophages in morbidly obese subjects. This project is based on a clinical
      protocol performed in massively obese subjects (BMI>40 kg/m²), where drastic weight loss is
      achieved by gastric bypass. This project has several objectives. It will allow us to
      characterize the infiltration of macrophages in the subcutaneous adipose tissue of 60 obese
      subjects compared with 20 normal-weight subjects, to study the evolution during
      surgically-induced weight loss and to compare the infiltration observed in adipose tissue to
      that of other tissues (visceral adipose tissue, muscle, liver, bowel and stomach). This study
      will be not only quantitative (number of macrophages) but also qualitative by characterizing
      the phenotype of macrophages with transcriptomics and immunohistochemical approaches. We will
      analyze the relationships between morphological characteristics of adipose tissue and
      clinical and biochemical parameters related to insulin sensitivity. More generally, this
      project might lead us to go thoroughly into the knowledge of the link between obesity and
      associated comorbidities, particularly metabolic complications, and to consider novels
      therapeutic strategies.
    

Observational model: Cohort
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        Inclusion Criteria:

          -  Obese subjects group :

               -  Obesity with BMI> 40 kg/m² or obesity with BMI between 35 and 40 kg/M² with
                  comorbidities (OAS, diabetes, hypertension etc…)

               -  Age: 18-60

          -  Non obese subjects group

               -  Abdominal surgery planned

               -  Age: 18-60

        Exclusion Criteria:

          -  Inflammatory disease

          -  cancer

          -  stroke

          -  Drugs (AINS)
      
Biospecimen description: 
      adipose tissue, visceral adipose tissue, muscle, liver, bowel and stomach
    
Keywords: Obesity; macrophage infiltration; insulinoresistance; inflammation