title: Intramucosal acidosis and systemic host responses in abdominal aortic aneurysm surgery.
abstract: OBJECTIVE
  To assess the specific host responses to systemic endotoxemia and tumor necrosis factor (TNF) activation after abdominal aortic aneurysm surgery by measuring antiendotoxin core antibodies (EndoCab) immunoglobulin (Ig)G and IgM, and soluble p55TNF receptor concentrations. The role of the gut in initiating these immune responses was evaluated by correlating the systemic markers to changes in the intramucosal pH of the sigmoid colon.
  
  
  METHODS
  Retrospective, reevaluation study.
  
  
  METHODS
  Vascular unit of a university hospital.
  
  
  METHODS
  Eleven patients who underwent abdominal aortic aneurysm repair surgery were selected from a larger patient cohort (n = 42) on the basis of their clinical outcome (four patients had fatal complications and seven patients had an uneventful recovery).
  
  
  METHODS
  After induction of anesthesia, intramucosal pH of the sigmoid colon was measured using tonometry. Blood samples were obtained from indwelling catheters or direct venipuncture preoperatively, during surgery, and daily until postoperative day 5.
  
  
  RESULTS
  Those patients who died developed intramucosal acidosis of the sigmoid colon intraoperatively. Significant consumption of both IgG and IgM EndoCab antibodies was found in all patients. By measuring the concentration of antibodies to a neutral antigen, i.e., tetanus toxoid, the consumption of IgG EndoCab antibody concentrations was shown to be a specific host response. In all patients, reciprocal changes in the serum concentrations of p55TNF receptor and interleukin (IL)-6 were observed. The percentage increase in p55TNF receptor and the concentration of IL-6 were significantly higher in the nonsurvivor group by 48 hrs. There were significant correlations between, intramucosal pH and EndoCab antibodies, intramucosal pH and p55 TNF receptor, and p55 TNF receptor and IL-6.
  
  
  CONCLUSIONS
  The development of colonic ischemia is associated with a significant consumption of IgG EndoCab antibodies and a simultaneous increase in soluble p55TNF receptor. This study provides further support for the concept that gut-derived endotoxin and the generation of TNF may play a role in the pathogenesis of complications after abdominal aortic aneurysm surgery.
authors.affiliation: Vascular Surgery Unit, Royal Victoria Hospital, Belfast, UK.
authors.forename: C V
authors.initials: CV
authors.lastname: Soong
authors.forename: M I
authors.initials: MI
authors.lastname: Halliday
authors.forename: G R
authors.initials: GR
authors.lastname: Barclay
authors.forename: J M
authors.initials: JM
authors.lastname: Hood
authors.forename: B J
authors.initials: BJ
authors.lastname: Rowlands
authors.forename: A A
authors.initials: AA
authors.lastname: Barros D'Sa
mesh_terms: D000138:Acidosis / Q000378:metabolism*; D000368:Aged; D015703:Antigens, CD / Q000097:blood*; D017544:Aortic Aneurysm, Abdominal / Q000276:immunology* / Q000378:metabolism / Q000601:surgery*; D015415:Biomarkers; D012809:Colon, Sigmoid / Q000098:blood supply; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007075:Immunoglobulin M / Q000097:blood*; D007136:Immunoglobulins / Q000097:blood*; D015850:Interleukin-6 / Q000097:blood; D007413:Intestinal Mucosa / Q000098:blood supply* / Q000378:metabolism; D007511:Ischemia / Q000378:metabolism*; D018124:Receptors, Tumor Necrosis Factor / Q000097:blood*; D047888:Receptors, Tumor Necrosis Factor, Type I; D012189:Retrospective Studies; D016019:Survival Analysis
chemical_list: D015703:Antigens, CD; D015415:Biomarkers; D007075:Immunoglobulin M; D007136:Immunoglobulins; D015850:Interleukin-6; D018124:Receptors, Tumor Necrosis Factor; D047888:Receptors, Tumor Necrosis Factor, Type I; C042866:antilipopolysaccharide antibodies