AIM: In preterm infants, inflammation and intra-alveolar fibrin formation characterize respiratory distress syndrome (RDS). Tissue factor (TF) is a link between inflammation and coagulation pathways. We investigated the relationship between TF and cytokines in preterm infants to gain information of the role of TF in the inflammatory response. METHODS: We measured TF in plasma and in tracheal aspirates and analysed TF on monocytes by flow cytometry and 13 cytokines from plasma, in 56 preterm infants (birthweight 600-1500 g) during their first week. RESULTS: Plasma TF increased and peaked on day 3 and correlated with both RDS and inversely with paO2/FIO2. On day 1, TF in tracheal aspirates was 10-fold higher than in plasma and correlated with plasma TF (4888 vs. 506 pg/mL, R = 0.692, p = 0.013, n = 12). Of main pro-inflammatory cytokines, plasma TF correlated post-natally with IL-8 and IL-6 but not with IL-1 or TNF-α. CONCLUSIONS: Respiratory morbidity associates with high TF in lungs and plasma. In sick newborn infants, upregulation of TF may be mediated by IL-6 and IL-8. High TF and pro-inflammatory cytokines may together participate in the pathogenesis of pulmonary and extrapulmonary injury in preterm infants through pro-inflammatory mechanisms.
AIM: In preterm infants, inflammation and intra-alveolar fibrin formation characterize respiratory distress syndrome (RDS). Tissue factor (TF) is a link between inflammation and coagulation pathways. We investigated the relationship between TF and cytokines in preterm infants to gain information of the role of TF in the inflammatory response. METHODS: We measured TF in plasma and in tracheal aspirates and analysed TF on monocytes by flow cytometry and 13 cytokines from plasma, in 56 preterm infants (birthweight 600-1500 g) during their first week. RESULTS: Plasma TF increased and peaked on day 3 and correlated with both RDS and inversely with paO2/FIO2. On day 1, TF in tracheal aspirates was 10-fold higher than in plasma and correlated with plasma TF (4888 vs. 506 pg/mL, R = 0.692, p = 0.013, n = 12). Of main pro-inflammatory cytokines, plasma TF correlated post-natally with IL-8 and IL-6 but not with IL-1 or TNF-α. CONCLUSIONS: Respiratory morbidity associates with high TF in lungs and plasma. In sick newborn infants, upregulation of TF may be mediated by IL-6 and IL-8. High TF and pro-inflammatory cytokines may together participate in the pathogenesis of pulmonary and extrapulmonary injury in preterm infants through pro-inflammatory mechanisms.