Thrombomodulin improves maternal and fetal conditions in an experimental pre-eclampsia rat model

The aim of this study was to investigate whether the consecutive administration of recombinant thrombomodulin (r-TM) for 4 days improves maternal and fetal conditions and physiological outcomes in an N'-nitro-L-arginine-methyl ester hydrochloride-induced and low-dose endotoxin-induced pre-eclampsia (PE).

r-TM or saline was administrated i.v. to normal pregnant and experimental PE rats for 4 days. The maternal condition, vascular endothelial growth factor receptor-1 (VEGFR-1), fetal conditions, uteroplacental blood flow (UPBF), and oxygenation in the placenta and fetal brain was evaluated on gestational day 21.

Significant increases in the mean arterial blood pressure, VEGFR-1 values and fetal death rate were observed in PE rats compared with control rats, while maternal and fetal bodyweight and fetal brain weight were substantially lower. Hypoperfusion and hypo-oxygenation in both the placenta and fetal brain tissues occurred in PE rats. Although r-TM failed to improve hypertension and affect the differences in maternal bodyweight between the groups, r-TM significantly improved hypoperfusion and fetal and maternal conditions, including VEGFR-1 values (6.5 ± 4.0 vs 2.2 ± 2.7 ng/mL, PE vs PE with r-TM, respectively; P < 0.05). Although not significant, a decrease in the fetal death rate was observed in PE rats administrated r-TM (36.1 ± 17.6% vs 25.0 ± 23.8%, P = 0.077).

The severe reductions in the UPBF and the placental oxygenation imply that regional hypoperfusion occurs in association with systemic mean arterial pressure. r-TM may be a candidate medical treatment for PE complications.