早产儿体重与血浆瘦素水平相关性的研究

目的　对早产儿生后体重下降和血浆瘦素水平之间的相关性进行动态研究 ,初步探讨瘦素在早产儿体重下降和能量平衡中的作用。方法　采用放射免疫分析法动态测定早产儿血浆瘦素水平 ,同时维持基本的液体和最低的能量需求 ,并进行为期 7～ 12d的观察。由专人定期测量体重、身长、头围 ,计算Kaup指数。结果　共有 2 6例早产儿入选 ,其中男 14例 ,女 12例 ,胎龄 30～ 36周 ,早产儿体重和瘦素浓度下降至最低点的时间为分别为生后第 (5 2± 1 6 )天和第 (4 7± 1 4 )天 ;两者下降的最大幅度分别为 (6 5± 3 0 ) %和 (5 9 6± 11 3) %。体重下降和血浆瘦素浓度下降之间呈显著正相关 (出生时 :n =2 6 ,r =0 76 6 ;第 3天 :n =2 6 ,r =0 6 36 ;第 5天 :n =2 6 ,r =0 6 2 9;第 7天 :n =2 6 ,r =0 717;第 9～ 12天 :n =2 4 ,r =0 5 87;P均 <0 0 1) ;两者下降至最低点的时间也高度相关 (r =0 6 11,P <0 0 1)。此外 ,血浆瘦素浓度和身长 (出生时 :n =2 6 ,r =0 6 0 9,P <0 0 1;第 3天 :n =2 6 ,r =0 4 19P <0 0 5 ;第 5天 :n =2 6 ,r =0 5 83,P <0 0 1;第 7天 :n =2 6 ,r =0 6 2 6 ,P <0 0 1;第 9～ 12天 :n =2 4 ,r =0 4 82 ;P <0 0 5 )、Kaup指数 (出生时 :n =2 6 ,r

Correlation between plasma leptin level and premature infant weight loss

OBJECTIVE: Leptin is an adipocyte-derived hormone regulating body weight and energy balance in animals and human being. Although the physiological functions of leptin in human are still unclear, its secretion is closely related to fat mass and energy expenditure in both adults and children. This study investigated whether the plasma leptin level was reduced in connection with the weight loss during the neonatal period and try to find out the role of leptin in body weight regulation and energy balance of premature infants. METHODS: The radioimmunoassay was used to determine the plasma leptin concentration. The first blood samples were obtained at the delivered, and then collected the samples every two days until the infants' body weight recovered to the birth weight or above. At the same time, the essential fluid and energy for the patients were supplied to keep their physiological functions. One person was appointed to take responsibility to examine the body weight, body length and head circumference. Then computed out their Kaup index from the first day to the seventh or twelfth day. RESULTS: A total of 26 premature infants were selected into the study, of which 14 cases were male and 12 female, and their gestational age ranged from 30 to 36 weeks. There was a significantly positive correlation between the premature newborns' body weight loss and their plasma leptin levels (the 1st day: n = 26, r = 0.766; the 3rd day: n = 26, r = 0.636; the 5th day: n = 26, r = 0.629; the 7th day: n = 26, r = 0.717; the 9th-12th day: n = 24, r = 0.587; P < 0.01). The time of body weight loss and the plasma leptin level which declined to extremely low were positively correlated. (r = 0.611, P < 0.01). The time when body weight loss declined to extremely low in 26 premature infants ranged form the 3rd to the 9th day after birth [(5.2 +/- 1.6) day], and that of the plasma leptin levels ranged form the 3rd to the 8th day after birth (4.7 +/- 1.4) day. The maximal ranges of the body weight loss and the plasma leptin decrease in 26 premature infants were (6.5 +/- 3.0)% and (59.6 +/- 11.3)%, respectively. In addition, there were significantly positive correlations among the plasma leptin level, the premature newborns' body length (the 1st day: n = 26, r = 0.609, P < 0.01; the 3rd day: n = 26, r = 0.419, P < 0.05; the 5th day: n = 26, r = 0.583, P < 0.01; the 7th day: n = 26, r = 0.626, P < 0.01; the 9th-12th day: n = 24, r = 0.482; P < 0.05), and the Kaup index (the 1st day: n = 26, r = 0.634; the 3rd day: n = 26, r = 0.534; the 5th day: n = 26, r = 0.542; the 7th day: n = 26, r = 0.611; the 9th-12th day: n = 24, r = 0.539; P < 0.01). Although the head circumference correlated positively with the plasma leptin level at the first week after the delivery (the 1st day: n = 26, r = 0.580, P < 0.01; the 3rd day: n = 26, r = 0.417, P < 0.05; the 5th day: n = 26, r = 0.426; P < 0.01). There was a lower correlation between them one week after the delivery (the 7th day: n = 26, r = 0.369; the 9th-12th day: n = 24, r = 0.323; P > 0.05). CONCLUSION: There was a significantly positive correlation between the plasma leptin level and the premature newborns weight loss. Leptin may participate in the regulation of energy balance and body weight of premature infants during neonatal life. Leptin may play an important role in growth and development of premature infants.