Coordinated release of tissue factor and tissue factor pathway inhibitor in VLBW infants

Abstract

Aim: Tissue factor (TF), a mediator between coagulation and inflammation, is upregulated in alveolar compartment and circulation in very low birthweight (VLBW) infants. We investigated the contribution of TF to systemic regulation of coagulation in VLBW infants.

Methods: We measured TF, total and free tissue factor pathway inhibitor (TFPIt, TFPIf), prothrombin fragment (F1 + 2), and thrombin-antithrombin complexes (TAT) in plasma from 51 VLBW infants during their first week of life.

Results: F1 + 2 in cord plasma was high (1385 pmol/mL) and decreased postnatally to 17% (p = 0.002). TAT decreased from a high cord concentration to 3% postnatally (p < 0.001). Plasma TF increased and peaked on day 3, showing no correlation with F1 + 2 or TAT. TFPIt and TFPIf increased postnatally, correlating with TF (day 1 TFPIf: R = 0.595, p < 0.001, day 3 TFPIf: R = 0.582, p < 0.001). Based on the TF/TFPIf ratio, a relative excess of plasma TF over TFPIf probably prevailed on day 3.

Conclusions: In VLBW infants plasma TF fails to associate with thrombin formation. This is partly explained by release of TFPI. Despite TFPI, the newborn VLBW infant is subjected to a substantial circulating pool of TF with potential proinflammatory effects.