Spear M L, Hassink S G, Leef K, O'Connor D M, Kirwin S M, Locke R, Gorman R, Funanage V L
Section of Neonatology, Department of Pediatrics, Christiana Care Health Services, Newark, DE 19718, USA.
Biol Neonate. 2001 Jul;80(1):35-40. doi: 10.1159/000047117.
Leptin, the protein product of the ob gene, is a potential placental growth factor and is integral to the body's system of energy regulation as shown in animal models. Premature infants are especially vulnerable to changes in energy regulation, and several studies have demonstrated a rapid fall in leptin values at birth. The purpose of the present investigation was to measure leptin levels in premature infants throughout hospitalization.
Eligible infants were less than 32 weeks' gestation, appropriate for gestational age, and hospitalized at Christiana Hospital Special Care Nursery. Serum samples for leptin analysis were drawn within 24 h of birth and twice a week thereafter until discharge. Concurrent growth measurements were obtained with each leptin sample. Body mass index, ponderal index, and midarm circumference/head circumference ratios were calculated to assess growth.
Leptin levels were low and remained low for the duration of the premature infants' hospitalization (mean +/- SD = 1.35 +/- 0.63 ng/ml/ml, range 0-3.06). After controlling for weight, there was a small (r(2) = 0.1, p < 0.00001) but significant correlation between leptin and postnatal age after 4 days of age. Despite an increase in caloric intake during the study period, there was no relationship between leptin and caloric intake. There were significant negative correlations between measurements of growth and both leptin and the leptin/weight ratio. Maternal diabetes and the use of steroids had small but significant effects on the leptin/weight ratio.
In this population of predominantly female premature infants, leptin levels were very low as compared to term infants, children and adults, and did not change appreciably over the study period. The low leptin levels seen in these premature infants are similar to those levels seen in malnourished adults, anorexics, and in animal models of starvation. We speculate that a critical adipose store needs to be reached before increased amounts of leptin can be adequately produced. Persistently low leptin levels may also reflect an immaturity in the hypothalamic-pituitary-adrenal axis.
瘦素是ob基因的蛋白质产物，是一种潜在的胎盘生长因子，并且在动物模型中显示其是机体能量调节系统不可或缺的一部分。早产儿尤其容易受到能量调节变化的影响，并且多项研究已经证实出生时瘦素值会迅速下降。本研究的目的是在住院期间全程测量早产儿的瘦素水平。
符合条件的婴儿为妊娠小于32周、适于胎龄，且在克里斯蒂安娜医院特殊护理新生儿病房住院。出生后24小时内采集用于瘦素分析的血清样本，此后每周两次直至出院。每次采集瘦素样本时同时进行生长指标测量。计算体重指数、体重 ponderal 指数以及上臂围/头围比值以评估生长情况。
早产儿住院期间瘦素水平较低且一直维持在低水平（均值±标准差=1.35±0.63 ng/ml/ml，范围0 - 3.06）。在控制体重后，4日龄后瘦素与出生后年龄之间存在小但显著的相关性（r² = 0.1，p < 0.00001）。尽管在研究期间热量摄入增加，但瘦素与热量摄入之间并无关联。生长指标测量值与瘦素及瘦素/体重比值之间存在显著负相关。母亲患糖尿病以及使用类固醇对瘦素/体重比值有小但显著的影响。
在这群以女性为主的早产儿中，与足月儿、儿童及成人相比，瘦素水平非常低，并且在研究期间没有明显变化。这些早产儿中所见的低瘦素水平类似于营养不良的成年人、厌食症患者以及饥饿动物模型中的水平。我们推测在能够充分产生更多瘦素之前需要达到临界脂肪储备。持续低瘦素水平也可能反映下丘脑 - 垂体 - 肾上腺轴的不成熟。
