Abstract OBJECTIVE: To study the changes and significance of serum hypoxia-inducible factor-1α (HIF-1α), endothelin-1 (ET-1) and calcium (Ca2+) levels in neonates with hypoxic pulmonary hypertension (HPH). METHODS: Seventy-five neonates with HPH (29 mild, 25 moderate and 21 severe) and 22 hospitalized neonates with non-HPH (control group) were enrolled. Pulmonary artery systolic blood pressure (PASP) was measured by bedside echocardiography within 24 hrs after birth. Serum levels of HIF-1α and ET-1 were measured using ELASA. Serum Ca2+ concentrations were measured with ion selective electrode. RESULTS: Serum levels of HIF-1α and ET-1 in the HPH group increased significantly compared with those in the control group (P<0.01), and were positively related with PASP (Rhif-1α=0.75, P<0.01; Ret-1=0.56，P<0.05). Serum Ca2+ levels in neonates with severe HPH were significantly lower than those in the control group (P<0.05). There were no correlation between serum Ca2+ levels and PASP. CONCLUSIONS: Serum HIF-1α and ET-1 levels are positively related with PASP in neonates with HPH, suggesting that serum HIF-1α and ET-1 may be involved in the occurrence of neonatal HPH. Serum Ca2+ levels are reduced in severe neonates with HPH, suggesting that serum Ca2+ may play a role in the occurrence of severe HPH.
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