Intestinal barrier dysfunction is involved in the development of systemic inflammatory responses and lung injury in type A aortic dissection: a case-control study

Background: The definite pathogenesis of lung injury complicated by type A aortic dissection (TAAD) remains unclear. In this paper, we investigated the relationship between intestinal injury, lung injury, and systemic inflammatory responses, with the aim of exploring the mechanism underlying intestinal injury and its impact on systemic inflammatory responses and lung injury in patients with TAAD. Methods: Patients with TAAD (n=36) and those with aortic root aneurysm (ARA) (n=30) were compared. TAAD patients were younger and had higher creatinine (Cr) than ARA patients. White blood cell (WBC) count, neutrophil count, neutrophil percentage, interleukin (IL)-6, IL-8, tumor necrosis factor a (TNF-a), C-reactive protein (CRP), histamine (HIS) levels, PaO2-FiO(2) ratio, diamine oxidase (DAO), intestinal fatty acid binding protein (iFABP), and peptidoglycan (PGN) were measured using the same laboratory methods between the two groups. Results: Increased WBC [(9.70 +/- 4.05)x109/L vs. (5.88 +/- 1.2)x109/L, P < 0.001], neutrophil [(7.65 +/- 4.27)x109/L vs. ( 3.40 +/- 0.97) x109/ L, P < 0.001], neutrophil percentage [(74.73 +/- 13.42)% vs. (57.67 +/- 9.45)%, P < 0.001], IL-6 ( 37.48 +/- 4.87 vs. 20.90 +/- 0.92 pg/mL, P < 0.001), IL-8 (97.15 +/- 9.11 vs. 69.46 +/- 3.17 pg/mL, P < 0.001), TNF-a (71.32 +/- 10.35 vs. 33.90 +/- 2.27 pg/mL, P < 0.001), CRP (10.67 +/- 1.62 vs. 4.43 +/- 0.26 mu g/ mL, P < 0.001), HIS (13.29 +/- 1.88 vs. 7.63 +/- 0.58 ng/mL, P < 0.001), DAO (24.94 +/- 4.72 vs. 10.92 +/- 2.44 U/L, P < 0.001), iFABP (879.01 +/- 190.12 vs. 206.35 +/- 42.20 pg/mL, P < 0.001), and PGN (31.10 +/- 5.51 vs. 12.52 +/- 2.20 ng/mL, P < 0.001) and decreased PaO2-FiO2 ratio (365.35 +/- 146.47 vs. 447.86 +/- 70.80 mmHg, P=0.01) were detected in TAAD group relative to ARA group. In TAAD group, positive correlations were detected between DAO and inflammatory cytokines [IL-6 (r=0.56, P < 0.001), IL-8 ( r= 0.61, P < 0.001), TNF-a (r=0.71, P < 0.001), and CRP (r=0.68, P < 0.001)], between iFABP and inflammatory cytokines [IL-6 (r=0.72, P < 0.001), IL-8 (r=0.71, P < 0.001), TNF- a (r= 0.90, P < 0.001), and CRP (r= 0.89, P < 0.001)], between DAO and PGN (r= 0.52, P < 0.001), between iFABP and PGN (r=0.74, P < 0.001), between PGN and inflammatory cytokines [IL-6 (r=0.85, P < 0.001), IL-8 (r=0.44, P < 0.001), TNF-a (r=0.61, P < 0.001), and CRP (r=0.73, P < 0.001)]. In acute TAAD subgroup, PGN and PaO2-FiO(2) ratio were negatively correlated (r=-0.50, P=0.036). Conclusions: Systemic inflammatory responses in TAAD patients may lead to lung and intestine injury, and the latter may be involved in the development of systemic inflammatory responses and lung injury in these patients.