Honzík T, Chrastina R, Hansíková H, Böhm M, Martincová O, Plavka R, Zapadlo M, Zeman J
Department of Paediatrics, First Faculty of Medicine, Charles University Prague, Czech Republic.
Prague Med Rep. 2005;106(3):297-306.
Carnitine plays an important role in energetic metabolism. The aim of the study was to characterize the carnitine status in term and preterm newborns with respect to gestational age, birth weight, haematocrit and red blood cell count (RBC). The effect of nutrition on carnitine levels in the first week of life was also studied. Total blood pool of free carnitine (FC), acylcarnitines (AC) and total carnitine (TC) were analysed in whole cord blood and postnatally in capillary blood obtained at the day 4-6 in 33 term newborns and at the day 7-10 in 27 preterm newborns using tandem mass spectrometry. Plasma level of carnitine in the cord blood was measured using radioenzymatic method. Cord plasma levels of FC, AC and TC were higher in preterm newborns in comparison with term newborns (p < 0.01), but the total blood pool of FC and TC in whole cord blood was lower in preterm newborns than in term newborns (p < 0.01) and positive correlation was found between FC and gestational age or birth weight (p < 0.05). In addition, positive correlation was found between AC and red blood cell count or haematocrit (p < 0.05). During the first week of life, blood pool of FC and TC in term newborns and AC and TC in preterm newborns decreased regardless of the type of enteral or parenteral nutrition. Our results indicate that preterm newborns are born with limited carnitine store. Interpretation of carnitine analyses in whole blood relies in addition to gestational age and birth weight on the haematocrit, especially in newborns with anaemia or blood hyperviscosity.
肉碱在能量代谢中起着重要作用。本研究的目的是根据胎龄、出生体重、血细胞比容和红细胞计数（RBC）来描述足月儿和早产儿的肉碱状况。还研究了营养对出生后第一周肉碱水平的影响。使用串联质谱法分析了33例足月儿出生时脐血及出生后第4 - 6天采集的毛细血管血，以及27例早产儿出生后第7 - 10天采集的毛细血管血中游离肉碱（FC）、酰基肉碱（AC）和总肉碱（TC）的全血池。采用放射酶法测定脐血中肉碱的血浆水平。与足月儿相比，早产儿脐血中FC、AC和TC的血浆水平更高（p < 0.01），但早产儿全脐血中FC和TC的全血池低于足月儿（p < 0.01），且FC与胎龄或出生体重之间存在正相关（p < 0.05）。此外，AC与红细胞计数或血细胞比容之间存在正相关（p < 0.05）。在出生后的第一周，无论肠内或肠外营养类型如何，足月儿的FC和TC血池以及早产儿的AC和TC血池均下降。我们的结果表明，早产儿出生时肉碱储备有限。除胎龄和出生体重外，全血中肉碱分析的解读还依赖于血细胞比容，尤其是在贫血或血液高粘滞度的新生儿中。
