Impact of Histological Chorioamnionitis on Tracheal Aspirate Cytokines in Premature Infants

Background: Histological chorioamnionitis (CHORIO) may increase inflammatory mediators in the lungs of preterm infants.

Objective: To study the impact of CHORIO on tracheal aspirate (TA) cytokines in ventilated infants.

Design/methods: TA samples collected within 48 hours after birth from 40 ventilated neonates (gestational age [GA] <30 weeks, body weight [BW] <1250 g) were analyzed. Levels of 12 cytokines (interleukin [IL]-1α, IL-1β, IL-2, IL-4, IL-6, IL-8, IL-10, epidermal growth factor [EGF], interferon-γ [IFN-γ], monocyte chemotactic protein-1 [MCP-1], tumor necrosis factor-α [TNF-α], vascular endothelial growth factor [VEGF]) were measured using a biochip multianalyte immunoassay (Randox Laboratories, Antrim, UK). Total protein was measured by the Bradford assay. CHORIO assessment was done by a blinded pathologist.

Results: Twenty-six infants (GA 26.6 ± 1.4 weeks, BW 852 ± 162 g) had no CHORIO and 14 (GA 25.1 ± 1.0 weeks, BW 776 ± 164 g) had CHORIO. IL-1α, IL-1β, IL-8, and VEGF were significantly higher in TA of infants with CHORIO. After correction for dilution, IL-1α, IL-1β, and IL-8 were significantly elevated. Increased TA total cell count correlated with CHORIO, VEGF, EGF, MCP-1, IL-8, and IL-6 TA levels (all p ≤ 0.02). Ventilator, oxygen supplementation, and hospital days correlated with TA IFN-γ levels (all p ≤ 0.01).

Conclusion: CHORIO is associated with increased specific proinflammatory mediators in TA samples of preterm infants.