Bednarek Francis J, Bean Stephen, Barnard Marc R, Frelinger A L, Michelson Alan D
Neonatology, Department of Pediatrics, University of Massachusetts Medical School and UMass Memorial Health Care, Worcester, MA 01655, USA.
Thromb Res. 2009 May;124(1):42-5. doi: 10.1016/j.thromres.2008.10.004. Epub 2008 Nov 20.
We have previously demonstrated that, as compared to adults, the platelets of extremely low birth weight (ELBW) neonates are markedly hyporeactive on day 0-1 of life. The purpose of this study was to examine the age dependency of this hyporeactivity.
On days 0-1, 3-4, and 10-14, peripheral blood was collected from 14 stable ELBW neonates and compared to peripheral blood from normal adults run in parallel. Whole blood flow cytometry was used to examine the activation-dependent increase in platelet surface P-selectin (reflecting degranulation) and platelet surface binding of factor V/Va (reflecting platelet surface procoagulant activity) and decrease in platelet surface glycoprotein (GP) Ib (the von Willebrand factor receptor).
In the physiologic milieu of whole blood, ELBW neonatal platelets on days 0-1 and 3-4 were markedly less reactive than adult platelets. However, by day 10-14, the platelet function of ELBW neonates improved significantly, although not completely to adult levels.
The age-dependent platelet hyporeactivity of ELBW neonates demonstrated in this study may be a contributing factor to the similar age-dependent propensity of ELBW neonates to intraventricular hemorrhage.
我们之前已经证明，与成年人相比，极低出生体重（ELBW）新生儿在出生后0至1天的血小板反应性明显低下。本研究的目的是检查这种低反应性的年龄依赖性。
在出生后0至1天、3至4天和10至14天，从14名病情稳定的ELBW新生儿采集外周血，并与同时检测的正常成年人外周血进行比较。采用全血流式细胞术检测血小板表面P-选择素（反映脱颗粒）激活依赖性增加、因子V/Va的血小板表面结合（反映血小板表面促凝活性）以及血小板表面糖蛋白（GP）Ib（血管性血友病因子受体）减少情况。
在全血的生理环境中，出生后0至1天和3至4天的ELBW新生儿血小板反应性明显低于成年血小板。然而，到出生后10至14天，ELBW新生儿的血小板功能显著改善，尽管尚未完全达到成人水平。
本研究中所证明的ELBW新生儿血小板反应性的年龄依赖性低下，可能是ELBW新生儿发生脑室内出血具有相似年龄依赖性倾向的一个促成因素。
