Relationship of insulin-like growth factor-I, insulin-like growth factor binding protein-3, insulin, growth hormone in cord blood and maternal factors with birth height and birthweight

BACKGROUND: To determine whether the following factors are related to birthweight or birth height, we measured insulin-like growth factor (IGF)-I, insulin-like growth factor binding protein (IGFBP)-3, insulin and growth hormone (GH) levels in cord blood and also observed the relationship between birthweight, birth height and maternal factors. METHODS: One hundred and ninety-four cord bloods were collected, 106 from males and 88 from females. Three newborns were small for gestational age (SGA), 168 were appropriate (AGA) and 23 were large (LGA); 21 newborns were preterm and 172 were term. RESULTS: Levels of IGF-I and IGFBP-3, measured by enzyme-linked immunosorbent assay, were significantly lower in preterm babies (35.3 +/- 15.1 and 1025.6 +/- 562.8 ng/mL, respectively) than in term babies (61.6 +/- 39.5 and 1252.6 +/- 403.2 ng/mL, respectively; P < 0.01), but neither insulin nor GH levels, measured by radioimmunoassay, showed any significant difference between the two groups (P > 0.05). Among term babies, IGF-I and IGFBP-3 levels were significantly higher in the LGA group (96.1 +/- 34.1 and 1544.7 +/- 418.1 ng/mL, respectively) than in the AGA group (56.4 +/- 37.6 and 1212.8 +/- 383.4 ng/mL, respectively; P < 0.01). Levels of IGF-I and IGFBP-3 showed significant correlation with birthweight and length, respectively (P < 0.01), although GH and insulin levels did not (P > 0.05). There was a significant correlation between IGF-I and IGFBP-3 levels (P < 0.01, r = 0.64), but IGF-I and IGFBP-3 levels showed no relationship with GH or insulin levels. Birthweight correlated significantly with prepartum maternal weight, maternal weight gain and maternal height (P < 0.05), but birth length correlated significantly only with maternal height (P < 0.05). CONCLUSIONS: Our results suggest that fetal growth depends on fetal levels of IGF-I and IGFBP-3 and maternal factors, not on insulin or GH. Levels of IGF-I and IGFBP-3 may not be regulated by insulin alone, but by the complex interactions between several factors, such as insulin, GH and maternal factors.     

Longitudinal investigation of the relationship between breast milk leptin levels and growth in breast-fed infants

BACKGROUND: It has been shown that leptin is present in breast milk and human mammary epithelial cells are able to synthesize leptin. It has been suggested that leptin in human milk might be involved in the regulation of postnatal nutrition and growth. AIMS: To investigate whether there is a relationship between leptin levels in human milk and weight gain in the postnatal period and to compare variations of milk-borne maternal leptin concentrations for small for gestational age (SGA), large for gestational age (LGA) and appropriate for gestational age (AGA) infants. INFANTS AND METHODS: Forty-seven healthy lactating women aged from 17-38 years and their infants were included in the study. The infants were separated into three groups according to birth weight as SGA (n = 11), LGA (n = 14) and AGA (n = 22). All infants were fed with breast milk during the study period. Anthropometric measurements were performed on the 15th day of life and at 1, 2, and 3 months of age, and the body mass index (BMI) of the infants' mothers was calculated. Breast milk leptin levels were analyzed by radioimmunoassay. RESULTS: Breast milk leptin levels were found reduced in the SGA group and increased in the LGA group compared to the AGA group at 15 days of life (13.4 +/- 2.2, 28.5 +/- 4.4 and 18.4 +/- 2 ng/ml, respectively; p <0.05). At 1 month of age, leptin levels in breast milk were significantly lower in the LGA group than in the AGA group (15.5 +/- 4.9, 19.4 +/- 1.7 ng/ml, respectively; p<0.05). There was no difference among the three groups at 2 and 3 months of age (p>0.05). There was a positive correlation between birth Weight and breast milk leptin levels on the 15th day (r = 0.47, p = 0.001). A negative correlation was found between weight gain during the first 15 days and 1 month of life and breast milk leptin levels on the 15th day (r = -0.44, p = 0.002; r = -0.40, p = 0.005, respectively). No relationship could be determined between breast milk leptin levels and BMI of the mothers. CONCLUSION: Maternal milk of SGA, LGA and AGA infants had different leptin levels, especially during the first month of life. More rapid growth was shown in the SGA infants during the first postnatal 15 days compared to AGA and LGA infants, and human milk leptin levels were significantly reduced in the SGA group. However, LGA infants gained more weight during the second 15 days of life and breast milk leptin levels were dramatically decreased in LGA and increased in SGA infants at the end of first month of life. These findings suggest that the presence of leptin in breast milk might have a significant role in growth, appetite and regulation of nutrition in infancy, especially during the early lactation period, and the production of leptin in breast tissue by human mammary epithelial cells might be regulated physiologically according to necessity and state of the infant.     

脑源性神经营养因子与新生儿出生体重的关系

目的：该文通过检测新生儿脐血脑源性神经营养因子（brain-derived neurotrophic factor,BDNF）的水平,探讨BDNF与新生儿出生体重的关系,并对相关因素进行分析。方法：根据出生体重,将51 例足月第1胎健康新生儿分为3 组:①小于胎龄组（SGA）8例;②适于胎龄组（AGA ）31例;③大于胎龄组（LGA）12例。测量新生儿身长、体重及其母亲的身高、体重,并对脐血中BDNF、瘦素（LEP）、胰岛素（INS）、总胆固醇（TC）、甘油三酯（TG）进行检测。结果：SGA组的BDNF明显高于AGA组和大于LGA组,AGA组和LGA组中BDNF没有差异;多元逐步回归分析显示BDNF值与新生儿出生体重、体重指数存在负相关关系。LEP与BDNF不呈相关趋势（P>0.05）,INS与BDNF也不呈相关趋势（P>0.05）。INS 与LEP呈现正相关（P<0.05）。LEP与新生儿体重、产妇体重及其BMI呈正相关,而TC,TG在3组新生儿中差异无显著性。结论：BDNF是新生儿体重的重要影响因素,而且不受LEP,INS的影响。     

Insulin, insulin-like growth factors-I and -II and insulin-like growth factor binding protein-3 in newborn serum: association with normal fetal head growth and head circumference

The insulin-like growth factors (IGF) and their binding proteins (IGFBP) have been implicated in the regulation of fetal weight and length. The aim of our study was to determine the relationship between head circumference at birth and serum levels of IGF-I, IGF-II, IGFBP-3 and insulin in full-term appropriate-for-gestational age (AGA) infants. Serum samples were obtained from 77 singleton full-term neonates, 69 AGA and 8 small-for-gestational age (SGA). The AGA infants were divided into three groups by head circumference: Group 1: < or = 3rd percentile; Group 2: at 50th percentile; Group 3: > or = 97th percentile. Serum levels of IGF-I, IGF-II, IGFBP-3 and insulin were determined with commercial kits and immunometric methods. There were no statistically significant differences in mean serum levels of IGF-I, IGF-II and IGFBP-3 between the groups. A significantly higher mean serum insulin level was noted in the AGA infants with a head circumference > or = 97th percentile compared to those with a head circumference < or = 3rd percentile (4.6 +/- 0.3 vs 3.3 +/- 0.6 microU/ml; p = 0.04), and in AGA infants with a head circumference above the 50th percentile compared to those with a head circumference below the 50th percentile (4.4 +/- 0.4 vs 3.3 +/- 0.3 microU/ml; p = 0.01). AGA infants with a head circumference above or below the 50th percentile did not differ statistically in their mean IGF-II and IGFBP-3 serum level, while IGF-I differed statistically between the groups (18 +/- 2.7 vs 11.6 +/- 1.6 ng/ml, respectively; p = 0.045). Using univariate analysis, head circumference correlated positively with insulin (r = 0.29; p = 0.016) and with IGF-I (r = 0.26; p = 0.03). A stepwise multivariate linear regression analysis, however, did show statistically significant correlation of head circumference with birth weight (f = 36; p = 0.0001), and only marginally with birth length (f = 4.7; p = 0.06) and insulin (f = 3.4; p = 0.07). No correlations were found between head circumference and IGF-I, IGF-II or IGFBP-3. These data suggest that apart from genetic and nutritional factors, insulin may play a role in promoting intrauterine head growth, as reflected by head circumference at birth.     

Serum leptin, IGF-I and insulin levels in preterm infants receiving parenteral nutrition during the first week of life

Leptin is involved in the regulation of body weight through a feedback signal between adipose tissue and the satiety center, to decrease food intake and increase energy expenditure. Newborn infants experience physiological weight loss during the first week of life. The leptin level may be decreased to enhance food intake and to decrease energy expenditure for physiological adaptation during early postnatal days. Insulin-like growth factor-I (IGF-I) and insulin are involved in the regulation of perinatal growth. Leptin might be interrelated with IGF-I or insulin, since both of these have adipogenic and somatotropic effects. We therefore hypothesized that leptin, IGF-I and insulin would be decreased during the first week of life, concurrently with physiological weight loss. Thirty preterm AGA infants (birth weight 1.574+/-313 g; GA 31.9+/-2.2 wk) were studied. All infants received parenteral nutrition from the third day after birth. Leptin was significantly decreased during the first week of life, and insulin was significantly increased at day 7 vs. day 1 and day 3. IGF-I did not change during the first week of life. Leptin was positively correlated with body weight (r = 0.368, p<0.01), body mass index (r = 0.267, p<0.05), and serum IGF-I (r = 0.330, p <0.01), but not with serum insulin. The percent of weight reduction during the first week of life was not correlated with the percent of leptin reduction during the first week of life. In conclusion, leptin was significantly decreased and positively correlated with body weight and IGF-I during the first week of life. Changes of leptin and insulin might be related to postnatal adaptation in metabolism, but the exact role of leptin, IGF-I and insulin in postnatal physiological weight loss is not clear.     

大于胎龄儿脐血脂联素水平测定及其临床意义

目的探讨大于胎龄儿(LGA)血脂联素水平变化及其对新生儿的影响。方法研究对象为LGA和适于胎龄儿(AGA)各30例。应用酶联免疫吸附法(ELISA)测定脐血和产妇血脂联素水平,用免疫比浊法测定三酰甘油(TG)、总胆固醇(TCH)、低密度脂蛋白胆固醇(LDL-c)、高密度脂蛋白胆固醇(HDL-c)水平,并分析脐血脂联素水平与母血脂联素、新生儿性别、出生体质量、体质量指数(BMI)、胎盘重量和血脂水平的相关性。结果1.LGA脐血浆脂联素水平低于AGA,差异有非常显著性(P<0.01);LGA血TG、TCH、LDL-c、HDL-c水平与AGA比较差异均无显著性(Pa>0.05)。2.LGA血浆脂联素水平与新生儿出生体质量、BMI、胎盘重量、脐血TG水平均呈显著负相关(r=-0.848,-0.785,-0.835 Pa<0.001),与母血脂联素水平、新生儿身长、孕前和分娩时产妇体质量及其BMI、其他脐血脂成分无相关性(Pa>0.05)。3.LGA男婴和女婴脐血浆脂联素、血脂各成分水平比较差异均无显著性(Pa>0.05)。结论血脂联素水平变化与LGA的发生有关,测定脐血脂联素水平有助于判断LGA的发展趋势。     

Visual evoked potentials in term light-for-gestational-age infants and infants of diabetic mothers

The latency and amplitude of the first negative peak of visual evoked potentials (VEP) were evaluated in 52 term infants, investigated within 48 h after birth. Sixteen were light-for-gestational-age (LGA), 16 were appropriate-for-gestational-age (AGA) and 20 were infants of diabetic mothers (IDM). The VEP latency was shorter in LGA infants compared to AGA infants, and it was closely related to the birth weight deviation. The VEP latency was inversely related to gestational age and positively related to head circumference. When corrected for gestational age and head circumference, the VEP latency was not significantly different between the subgroups, nor related to the birth weight deviation, ponderal index or skinfold thickness. Thus, it could be argued that the high conduction velocity in LGA infants is due to stress maturation or alternatively due to the smaller head circumference. The VEP amplitude was higher in LGA infants when compared with AGA infants, and inversely related to the birth weight deviation. No differences were found in VEP latency or VEP amplitude between IDM and AGA infants.     

Leptin, insulin, and glucose serum levels in large-for-gestational-age infants of diabetic and non-diabetic mothers

BACKGROUND: It has been suggested that hyperleptinemia could be caused by hyperinsulinemia in infants of diabetic mothers (IDMs). AIM: To compare leptin, insulin, and glucose levels in large-for-gestational-age (LGA) and appropriate-for-gestational-age (AGA) infants. Methods: A cross-sectional study was conducted in IDMs, infants of non-diabetic mothers (INDM) and AGA infants. RESULTS: Seventy-seven newborns were studied (11 IDM, 16 INDM, and 50 AGA infants). Leptin levels were significantly higher in LGA infants than in the AGA group and a trend for higher levels in IDM than NIDM was observed. Insulin levels and insulin resistance were significantly higher in IDMs. Glucose levels were lower in both groups of LGA infants. CONCLUSIONS: We found insulin resistance, hyperinsulinism and hyperleptinemia in IDMs, and the trend of higher leptin levels in IDMs than INDMs shows that leptin could be related to insulin resistance in these infants.     

Intracellular magnesium and adipokines in umbilical cord plasma and infant birth size

Many epidemiologic studies have disclosed that restricted fetal growth has been associated with an increased risk of insulin resistance in adulthood. We studied the relationship of intracellular magnesium [Mg2+]i in cord blood platelets to adipocytokine and birth size. The subjects were 20 infants with small for gestational age (SGA) and 45 infants with appropriate for gestational age (AGA). By using a fluorescent probe, we examined [Mg2+]i of platelets in the cord blood. Cord plasma insulin, IGF-I, ghrelin, adiponectin, plasminogen activator inhibitor-1 (PAI-1), and leptin levels were determined with the use of ELISA. Mean [Mg2+]i was lower in the SGA than in the AGA groups (p < 0.001). Adiponectin and IGF-I were also lower in the SGA than in the AGA, whereas PAI-1 was higher in the SGA. [Mg2+]i was significantly correlated with birth weight, birth length, and adiponectin. Birth weight was also correlated with cord plasma IGF-I, adiponectin, and leptin. Quantitative insulin sensitivity check index (QUICKI) was lower in the SGA group than in the AGA group. [Mg]i and adiponectin were correlated with QUICKI in all subjects. [Mg]i, as well as leptin and IGF-I, reflect the extent of fetal growth. Decreased [Mg2+]i may be involved in the underlying processes to insulin resistance.     

小于胎龄足月新生儿和适于胎龄足月新生儿血清瘦素及胰岛素水平的变化

目的 探讨不同类型足月新生儿血清瘦素及胰岛素水平及其与胎儿宫内生长发育的关系.方法 收集2009年9月-2010年5月在山西省儿童医院新生儿科住院的无严重疾病的88例足月新生儿的临床资料,其中44例小于胎龄儿(SGA),44例适于胎龄儿(AGA),用酶联免疫吸附测定法(ELISA)检测其出生24 h内血清瘦素及胰岛素水平,并分析血清瘦素和胰岛素水平与出生体质量的关系.采用SPSS 17.0软件进行统计学分析.结果 AGA组血清瘦素水平及血清胰岛素水平均高于SGA组(t=-73.624、-11.729,Pa<0.01);血清瘦素水平及血清胰岛素水平与出生体质量均呈正相关(r=0.96、0.91,Pa<0.01);血清瘦素与胰岛素之间也存在正相关(r=0.85,P<0.01).结论 瘦素及胰岛素在一定程度上反映了胎儿宫内生长发育的情况,在调节足月儿的生长代谢中发挥了重要作用.     

脐血脂联素、瘦素水平与胎儿发育的相关性

目的 探讨脐血脂联素、瘦素水平与胎儿生长发育的关系.方法 选择2006年10月至2007年10月在我院产科出生的新生儿86例,根据不同出生体质量分为小于胎龄儿(SGA)组16例,适于胎龄儿(AGA)组41例,大于胎龄儿(LGA)组29例.胎儿娩出后立即断脐留脐血20ml,采用放射免疫分析法测定血清脂联素、瘦素水平,同时检测其血脂水平,测量新生儿生长参数,计算体质量指数(BMI).结果 (1)3组脐血瘦素和脂联素水平差异有统计学意义(P<0.001),LGA组明显高于AGA及SAG组(P<0.01);(2)脐血瘦素水平与体质量、胎龄、头围、身长、足长及胎盘重量呈正相关(P<0.01),脐血脂联素水平与出生体质量、头围、足长、BMI水平呈正相关(P<0.05).(3)脐血瘦素与脂联素水平呈显著正相关(P<0.01).(4)3组血脂水平比较差异无统计学意义;脐血脂联素、瘦素水平与血脂各指标间无明显相关性(P>0.05).结论 瘦素与脂联素在胎儿宫内生长和发育过程中起重要的调节作用.     

Serum leptin levels in twins and singleton newborns

BACKGROUND AND OBJECTIVE: Leptin is produced by the human placenta besides adipose tissue and is suggested to be related to fetal growth. In order to find out whether multiple pregnancy is a factor affecting serum leptin levels, we compared neonatal serum leptin concentrations of twins and singleton newborns who were all appropriate for gestational age (AGA). INFANTS AND METHODS: Thirty newborns were studied. Group 1 consisted of 15 infants from twin pregnancies and group 2 (control group) consisted of 15 infants from singleton pregnancies. Serum samples were taken at 24 hours following delivery and leptin concentrations were measured. RESULTS: There were no significant differences in birth weight, gestational age and male/female ratio between infants of twin and single gestations. However, serum leptin concentrations of twins (mean +/- SEM: 1.13 +/- 0.35 ng/ml) were significantly lower than of the singleton infants (4.27 +/- 0.63 ng/ml) (p < 0.001). CONCLUSION: Twin pregnancy might be a factor affecting serum leptin concentrations in newborn infants.     

脐血脂联素、瘦素水平与胎儿发育的相关性

目的 探讨脐血脂联素、瘦素水平与胎儿生长发育的关系.方法 选择2006年10月至2007年10月在我院产科出生的新生儿86例,根据不同出生体质量分为小于胎龄儿(SGA)组16例,适于胎龄儿(AGA)组41例,大于胎龄儿(LGA)组29例.胎儿娩出后立即断脐留脐血20ml,采用放射免疫分析法测定血清脂联素、瘦素水平,同时检测其血脂水平,测量新生儿生长参数,计算体质量指数(BMI).结果 (1)3组脐血瘦素和脂联素水平差异有统计学意义(P<0.001),LGA组明显高于AGA及SAG组(P<0.01);(2)脐血瘦素水平与体质量、胎龄、头围、身长、足长及胎盘重量呈正相关(P<0.01),脐血脂联素水平与出生体质量、头围、足长、BMI水平呈正相关(P<0.05).(3)脐血瘦素与脂联素水平呈显著正相关(P<0.01).(4)3组血脂水平比较差异无统计学意义;脐血脂联素、瘦素水平与血脂各指标间无明显相关性(P>0.05).结论 瘦素与脂联素在胎儿宫内生长和发育过程中起重要的调节作用.     

脐血脂联素、瘦素水平与胎儿发育的相关性

目的 探讨脐血脂联素、瘦素水平与胎儿生长发育的关系.方法 选择2006年10月至2007年10月在我院产科出生的新生儿86例,根据不同出生体质量分为小于胎龄儿(SGA)组16例,适于胎龄儿(AGA)组41例,大于胎龄儿(LGA)组29例.胎儿娩出后立即断脐留脐血20ml,采用放射免疫分析法测定血清脂联素、瘦素水平,同时检测其血脂水平,测量新生儿生长参数,计算体质量指数(BMI).结果 (1)3组脐血瘦素和脂联素水平差异有统计学意义(P<0.001),LGA组明显高于AGA及SAG组(P<0.01);(2)脐血瘦素水平与体质量、胎龄、头围、身长、足长及胎盘重量呈正相关(P<0.01),脐血脂联素水平与出生体质量、头围、足长、BMI水平呈正相关(P<0.05).(3)脐血瘦素与脂联素水平呈显著正相关(P<0.01).(4)3组血脂水平比较差异无统计学意义;脐血脂联素、瘦素水平与血脂各指标间无明显相关性(P>0.05).结论 瘦素与脂联素在胎儿宫内生长和发育过程中起重要的调节作用.     

IGF-I, leptin and active ghrelin levels in very low birth weight infants during the first 8 weeks of life

Aim:  We investigated the relationship between plasma insulin-like growth factor I (IGF-I), leptin, active ghrelin levels, and postnatal growth in very low birth weight (VLBW) infants.
Method:  Plasma IGF-I, leptin, and active ghrelin levels were measured at birth and at 2, 4, 6 and 8 weeks after birth in 61 VLBW infants, including 31 appropriate-for-gestational-age (AGA) and 30 small-for-gestational-age (SGA) infants.
Results:  Insulin-like growth factor I levels were the lowest at birth, but increased gradually over the first 8 weeks of life. IGF-I was positively correlated with body weight, body length and body mass index at all time points. Leptin levels did not change over the study period. Ghrelin levels were significantly lower at birth; however, there were no significant differences between the levels after 2 weeks of age. Leptin and ghrelin levels were not correlated with anthropometrical measures. IGF-I levels at birth were significantly lower in SGA than in AGA infants, but the leptin and ghrelin levels were not significantly different between the two groups.
Conclusion:  Insulin-like growth factor I is related to length and weight gain in the prenatal and the early postnatal periods in VLBW infants, but this does not appear to be the case for leptin and ghrelin.     

Leptin levels in children with insulin dependent diabetes mellitus

Leptin, a product of the ob gene, is a polypeptide hormone produced in adipose tissue that informs the brain about the amount of energy storage of body fat. It has very important effects on neuroendocrine functions and energy expenditure. The aim of our study was to determine leptin levels of children with insulin dependent diabetes mellitus (IDDM), which is known to affect body metabolism, and to investigate the relationship between duration of the disease, insulin dosage, HbA1c levels, body mass index (BMI), serum lipids and IGF-1 levels. Sixteen patients with IDDM (chronological age 13.8 +/- 2.6 years) whose HbAlc levels were 10.2 +/- 1.9 %, BMI 21.2. +/- 2.7 kg/m2, insulin dosage 0.9 +/- 0.4 U/kg/day and duration of the disease 6.7 +/- 2.6 years, and 12 healthy controls (13.4 +/- 2.6 years) were included in the study. Fasting plasma leptin levels were measured by radioimmunoassay method. The mean plasma leptin levels of the patient and the control groups were 19.1 +/- 7.6 ng/ml and 6.1 +/- 2.9 ng/ml, respectively, and significant difference was found between the two groups (p < 0.05). No correlation was found between leptin values and IGF-1, cholesterol, HDL-cholesterol, LDL-cholesterol, triglyceride levels, atherogenic index, insulin dosage or HbA1c levels in the patient group. A weak statistical correlation was determined between BMI and leptin levels in the IDDM group (r = 0.28, p < 0.05). A positive correlation was also found between leptin levels and the duration of the disease (r = 49, p < 0.05). As a result, it seems that leptin levels of children with IDDM differed from the levels of the control group significantly, and that the duration of insulin therapy was responsible for this difference.     

Immaturity or starvation? Longitudinal study of leptin levels in premature infants

OBJECTIVE: 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. METHODS: 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. RESULTS: 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. CONCLUSION: 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.     

Maternal and fetal serum insulin-like growth factor-I (IGF-I) IGF binding protein-3 (IGFBP-3), leptin levels and early postnatal growth in infants born asymmetrically small for gestational age

This study was planned to investigate the relationship between birth weight and insulin-like growth factor-I (IGF-I), IGF binding protein-3 (IGFBP-3), and leptin levels in neonates with normal growth (appropriate for gestational age: AGA) and retarded growth (small for gestational age: SGA); and to evaluate these growth factors' effects in early postnatal growth. All newborns were full-term: gestational age 3,841 weeks. Of 50 neonates, 25 were SGA. IGF-I, IGFBP-3 and leptin levels were measured in maternal serum and venous cord blood at birth and at 15 days of life of neonates using specific RIAs. Maternal serum leptin concentrations were significantly higher than cord blood leptin concentrations (p < 0.001). Maternal serum IGF-I, IGFBP-3 and leptin levels did not show correlations with birth weight. In contrast, there were significantly positive correlations between birth weight and venous cord blood IGF-I, IGFBP-3 and leptin levels (p < 0.001). In the SGA group, the newborns with a slow postnatal growth pattern had lower umbilical cord serum IGF-I levels compared with newborns with a normal growth pattern. A similar result was also found in the AGA group. Similar results were not found for serum leptin and IGFBP-3. In conclusion, cord blood IGF-I, IGFBP-3 and leptin levels play an important role in the regulation of fetal and neonatal growth. It is likely that IGF-I has a more important role than the other factors in early postnatal growth.     

Influence of gestational age and intrauterine growth on leptin concentrations in venous cord blood of human newborns

BACKGROUND: The ob gene product leptin is involved in the regulation of body weight and energy expenditure, suggesting a potential role of leptin in embryonal and fetal development and progression of pregnancy. In term infants, leptin concentrations showed a positive correlation with birth weight. We aimed at comparing leptin cord blood levels in AGA (appropriate for gestational age) to SGA (small for gestational age) preterm and term newborns. PATIENTS AND METHODS: Ninety-seven human newborns, 47 females and 50 males, 33 born at term and 64 born before 36 weeks of gestation, were studied prospectively. Leptin concentrations in venous cord blood were determined using a specific RIA (radioimmunoassay). RESULTS: In term newborns, mean gestational age (GA) was 39 weeks (wk) (+/- 0.7 wk) and mean birth weight (BW) was 3316 g (+/- 473 g); in preterm newborns (n = 64), mean GA was 30 wk (+/- 5.0 wk) and mean BW was 1398 g (+/- 505 g). Mean standard deviation score of birth weight (BW SDS) was calculated as - 0.47. Mean leptin concentrations in term newborns differed significantly from those in preterm newborns (9.21 +/- 2.63 ng/ml vs. 1.58 +/- 0.88 ng/ml; p < 0.0001). In preterm and term infants, leptin concentrations showed a linear correlation with BW (r = 0.46; p < 0.0001) and GA (r = 0.48; p < 0.0001), respectively. Leptin levels were best predicted by an exponential regression model with GA (Leptin = exp(- 4.41 + 0.14 x GA); r = 0.61; p < 0.0001). Using multivariate regression analysis (r = 0.57; p < 0.0001), we found significant influences of GA (p < 0.00001) and BW SDS (p < 0.05) on leptin levels. No difference was observed between leptin values in AGA versus SGA preterm infants. CONCLUSION: These data suggest fetal leptin levels to be primarily determined by GA and additionally modulated by growth restriction in term newborns. We found a dramatic increase at weeks 33 to 35 of gestation and no modulation by BW SDS in very preterm infants.     

新生儿血清瘦素水平与生长发育关系研究

目的：探讨新生儿血清瘦素与生长发育的关系。方法：采用放射免疫法检测80例新生儿静脉血和脐血瘦素水平,其中66例足月儿分为大于胎龄儿(LGA)组18例,适于胎龄儿(AGA)组32例,小于胎龄儿(SGA)组16例。采用Rohrer’s指数=出生体重(g)×100/身长(cm)~3估测新生儿营养状态。结果：早产儿血清瘦素水平明显低于足月儿[(0.66±1.03)ng/ml vs(3.59±2.16)ng/ml],P<0.01;足月儿中AGA血清瘦素水平[(3.06±0.96)ng/ml]明显低于LGA[(4.03±2.22)ng/ml],而高于SGA[(1.13±1.98)ng/ml];足月新生儿血清瘦素水平与Rohrer’s指数、新生儿体重、胎龄呈显著正相关(r=0.61,0.68,0.62,P均<0.01)。结论：新生儿体内瘦素是反映新生儿的发育和营养状态的有用指标。[中国当代儿科杂志,2003,5(1):29-30]