血小板活化因子及其乙酰水解酶在新生儿感染中的变化及临床意义

Changes and significance of platelet-activating factor and platelet-activating factor-acetylhydrolase in neonatal infection

目的检测感染新生儿血浆血小板活化因子(PAF)水平及其乙酰水解酶(PAF-AH)的活性,探讨两者在新生儿感染中的变化及临床意义。方法以复旦大学附属儿科医院新生儿科病房收治的日龄<30d的新生儿为研究对象。依据感染部位和程度分为全身感染组、局部感染组及非感染组;依据日龄分为早期新生儿(≤7d)和晚期新生儿(>7d)。采集研究对象桡动脉血标本,对全身感染组中合并器官功能衰竭的患儿在感染的第1、3、5和7天增加采集桡动脉血标本。测定血浆PAF水平(μg.L-1)和PAF-AH活性(μmol.L-1.min-1)。分析感染程度、性别、日龄和出生体重对血浆PAF水平和PAF-AH活性的影响,比较不同感染组PAF水平和PAF-AH活性的差异,观察全身感染合并器官功能衰竭患儿血浆PAF水平和PAF-AH活性在病程1～7d的变化趋势。结果研究期间共收治247例新生儿,男146例,女101例;平均日龄9.2(1～57)d;平均胎龄35.85(27～43)周;平均出生体重2517(906～4750)g。全身感染组91例,局部感染组63例,非感染组93例。①新生儿血浆PAF水平与感染程度相关(P=0.000);血浆PAF-AH活性与感染程度及日龄(P均为0.000)相关。②全身感染组血浆PAF水平(9.5±8.1)显著高于局部感染组(5.3±3.2)及非感染组(4.6±3.5)。早期新生儿中,全身感染组血浆PAF-AH活性(5.7±2.7)显著低于局部感染组(7.3±2.9)和非感染组(7.3±2.5)。晚期新生儿中,全身感染组血浆PAF-AH活性(7.0±2.5)显著低于局部感染组(9.7±2.2)和非感染组(9.7±2.7)。③全身感染组合并器官功能衰竭的9/12例存活患儿在病程的1～7d血浆PAF水平呈下降趋势,PAF-AH活性呈上升趋势。3/12例死亡患儿中两者的变化趋势则相反。④全身感染组31/91例确诊败血症患儿中,革兰阴性菌感染者血浆PAF水平(13.1±11.0)显著高于革兰阳性菌感染者(5.4±3.9),PAF-AH活性(4.9±2.1)显著低于革兰阳性菌感染者(7.9±2.4)。结论新生儿严重感染时血浆PAF水平增高,PAF-AH活性降低,两者的变化趋势与预后相关。

Objective To evaluate the relationship between platelet-activating factor（PAF）/platelet-activating factor-acetylhydrolase（PAF-AH） and neonatal infection and to observe the trends of plasma PAF level and PAF-AH activities during the course of infection by measuring plasma PAF levels and PAF-AH activities in neonates with infection.Methods Neonates admitted to the neonatal ward of Children＇s Hospital of Fudan University from July to December in 2008 were enrolled.According to the locations and severity of infection,the patients were divided into 3 groups,general infection group,local infection group and non-infection group.Plasma samples of infection groups were taken within 48 h after infection,others were taken during hospitalization period.Besides,plasma samples were taken on the first,third,fifth and seventh day of infection from the neonates who had severe infection with organ dysfunction to observe the trends of plasma PAF levels and PAF-AH activities during the course of infection.The plasma PAF levels were measured by ELISA,and PAF-AH activities were measured using PAF Acetylhydrolase Assay Kit from Cayman Chemical Company.The plasma PAF levels（μg·L^-1） and PAF-AH activities（μmol·L^-1·min^-1） were compared in different groups and the changes of the plasma PAF levels and PAF-AH activities in severe general infection neonates were compared.Results Total 247（146 boys and 101 girls） neonates were enrolled in the study.Average age,gestational age and birth weight were 9.2（1~57）d,35.85（27~43）weeks and 2 517（906~4 750）g,respectively.General infection group,local infection group and non-infection group included 91,63 and 93 neonates,respectively.①Multiple linear regression analysis showed that the plasma PAF levels had relation with severity of infection（P=0.000）,no relation with sex,gestional age,birth weight and age;The plasma PAF-AH activities had relation with severity of infection and age（both P=0.000）,but had no relation with sex,gestational age and birth weight.The plasma PAF-AH activities were lower in early stage neonates than that in late stage neonates.②Mean plasma PAF levels were significantly higher in infants with general infection（9.5±8.1） than those in infants with non-infection group（5.3±3.2）and local infection group（4.6±3.5）（P=0.000）.In early stage or late stage neonates,plasma PAF-AH activities of general infection group（5.7±2.7,7.0±2.5） were significantly lower than those of non-infection group（7.3±2.9,9.7±2.2,respectively） and local infection group（7.3±2.5,9.7±2.7,respectively）.③The plasma PAF levels of 9/12 alive children with multiple organ dysfunction in the course of 1-7 d decreased and plasma PAF-AH activities increased.It was opposite in 3/12 deaths.④Infants with sepsis caused by Gram negative bacteria had higher plasma PAF levels and lower PAF-AH activities than those with sepsis caused by Gram positive bacteria（P=0.005）.Conclusions Plasma PAF levels were positively correlated and PAF-AH activities were negatively correlated with the severity of infection.Plasma PAF levels and PAF-AH activities showed variations during the course of infection.The trends of variations may be correlated with the prognosis.