title: The role of obesity in the immune response during sepsis.
abstract: OBJECTIVE
  Sepsis is one of the most important causes of mortality in the developed world, where almost two-thirds of the population suffer from obesity. Therefore, the coexistence of both conditions has become frequent in clinical practice and a growing number of clinical studies attempts to examine the potential effect of obesity on sepsis with controversial results up to now. The present study investigates how obesity influences the immune response of septic patients, by assessing the number and activation state of adipose tissue macrophages, serum and adipose tissue tumor necrosis factor-alpha (TNFα) levels and plasma oxidative stress markers.
  
  
  METHODS
  The study included 106 patients, divided into four groups (control n=26, obesity n=27, sepsis n=27 and sepsis and obesity n=26). The number of macrophages in subcutaneous and visceral adipose tissue (SAT and VAT) and their subtypes (M1 and M2) were defined with immunohistochemical staining techniques under light microscopy. TNFα mRNA levels were determined in SAT and VAT using real-time reverse transcription-PCR. Serum levels of TNFα were determined with sandwich enzyme-linked immunosorbent assay. Plasma oxidative stress was evaluated using selective biomarkers (thiobarbituric acid-reactive substances (TBARS), protein carbonyls and total antioxidant capacity (TAC)).
  
  
  RESULTS
  Sepsis increased the total number of macrophages and their M2 subtype in (VAT), whereas obesity did not seem to affect the concentration of macrophages in fat. Obesity increased TNFα mRNA levels (P<0.05) in VAT as well as the plasma TBARS (P<0.001) and protein carbonyls (P<0.001) in septic patients. The plasma TAC levels were decreased and the serum TNFα levels were increased in sepsis although they were not influenced by obesity.
  
  
  CONCLUSIONS
  Obesity is associated with elevated TNFα adipose tissue production and increased oxidative stress biomarkers, promoting the proinflammatory response in septic patients.
authors.affiliation: Division of Infectious Diseases, Department of Internal Medicine, Patras University Hospital, Rion-Patras, Greece.
authors.forename: A S
authors.initials: AS
authors.lastname: Kolyva
authors.affiliation: Department of Pathology, Patras University Hospital, Rion-Patras, Greece.
authors.forename: V
authors.initials: V
authors.lastname: Zolota
authors.affiliation: Department of Pathology, Patras University Hospital, Rion-Patras, Greece.
authors.forename: D
authors.initials: D
authors.lastname: Mpatsoulis
authors.affiliation: Department of Surgery, Patras University Hospital, Rion-Patras, Greece.
authors.forename: G
authors.initials: G
authors.lastname: Skroubis
authors.affiliation: Department of Internal Medicine, Patras University Hospital, Rion-Patras, Greece.
authors.forename: E E
authors.initials: EE
authors.lastname: Solomou
authors.affiliation: Division of Endocrinology, Department of Internal Medicine, Patras University Hospital, Rion-Patras, Greece.
authors.forename: I G
authors.initials: IG
authors.lastname: Habeos
authors.affiliation: Division of Infectious Diseases, Department of Internal Medicine, Patras University Hospital, Rion-Patras, Greece.
authors.forename: S F
authors.initials: SF
authors.lastname: Assimakopoulos
authors.affiliation: Department of Biochemistry and Biotechnology, University of Thessaly, Larissa, Greece.
authors.forename: N
authors.initials: N
authors.lastname: Goutzourelas
authors.affiliation: Department of Biochemistry and Biotechnology, University of Thessaly, Larissa, Greece.
authors.forename: D
authors.initials: D
authors.lastname: Kouretas
authors.affiliation: Division of Infectious Diseases, Department of Internal Medicine, Patras University Hospital, Rion-Patras, Greece.
authors.forename: C A
authors.initials: CA
authors.lastname: Gogos