| Abstract: Background and aim. Increased intra abdominal pressure (IAP) and a disturbed intestinal barrier function have both been identified as factors in the pathophysiology leading to multiple organ dysfunction syndrome. Our aim was to study mucosal barrier function in the ileum of pigs before and after a stepwise increase of IAP. In a recent study, we found that increasing IAP significantly reduced seromuscular perfusion, whereas blood flow of the intestinal mucosa was protected and remained above 75 % of baseline at 40 mmHg.
Methods. The study was performed on 8 anaesthetized pigs. Via laparotomy, samples of small bowel were taken out and transported to the laboratory for studies of barrier function. After baseline registrations, peritoneum was inflated with CO2 and IAP was increased stepwise by 10 mmHg at 10-min intervals up to 50 mmHg. Following 10 minutes recovery with release of IAP ,the abdomen was reopened and mucosa was sampled. Mucosal tissues were mounted in modified Ussing chambers and viability was assessed with electrophysiological variables. Barrier function was studied by measuring paracellular permeability to 51Cr-EDTA, transmucosal flux of the protein antigen horseradish peroxidase (HRP) and uptake of chemically-killed fluorescent E. coli K-12. Data are given as median [25-75th interquartile range].
Result. Increased IAP did not affect permeability to 51Cr-EDTA (3.0 [2.8-3.6] cm/s x 10-6 vs. 3.2 [2.4-4.2]) or HRP flux (12.1 [3.3-11.3] vs. 8.1 [3.6-42.2] pmol/h/cm2). In contrast, E. coli passage was three-fold increased after exposure to high IAP (22.6 [18.2-54.4] units) vs. baseline (8.1 [2.0-13.9]; p<0.05). Electrophysiology showed no significant changes after high IAP.
Conclusions. Enhanced bacterial uptake, but similar paracellular permeability and HRP flux, suggests specific disturbances in bacterial-epithelial interaction, leaving tight junctions and transcellular transport of proteins unaltered. This could have important implications for the pathogenesis of organ dysfunction after high IAP. Further studies including colon mucosa and of the mechanisms involved are warranted.
|
