|Year : 2017 | Volume
| Issue : 3 | Page : 765-769
A study of serum leptin level in both full-term and preterm newborns
Ahmed T Mahmoud1, Maha A El-Rafea Elbassuoni2, Dalia M Ellahony1, Sarah M. A. Elmohsen Sheir MBBCh 3
1 Department of Pediatrics, Faculty of Medicine, Menoufia University, Menoufia, Egypt
2 Department of Clinical Pathology, Faculty of Medicine, Menoufia University, Menoufia, Egypt
3 Department of Pediatrics, New Cairo Hospital, Cairo, Egypt
|Date of Submission||04-Sep-2016|
|Date of Acceptance||11-Dec-2016|
|Date of Web Publication||15-Nov-2017|
Sarah M. A. Elmohsen Sheir
Department of Pediatrics, New Cairo Hospital, Cairo, 11829
Source of Support: None, Conflict of Interest: None
This study aims to compare serum leptin level in preterm and full-term newborns in relation to clinical findings.
Leptin is a hormone made by fat cells that regulates the amount of fat stored in the body. Fetal and infant nutrition and growth have previously been correlated with disease in adulthood. The inadequate fat tissue in premature infants and infants with intrauterine growth restriction leads to impaired glucose metabolism and insulin resistance. Recent studies refer development of obesity, insulin resistance, and other metabolic disturbances later in life in patients born preterm or small for gestational age. Only few studies have been published regarding preterm infants and correlation of circulating leptin levels with birth weight and other anthropometric parameters.
Patients and methods
This is a follow-up (prospective) study included 40 neonates. All candidates had measurements of serum leptin level.
The data show that there is a positive significant correlation between cord blood leptin level and gestational age, weight, and length. During the follow-up of neonates, we found that weight gain was significantly higher in formula-feeding compared with breastfeeding neonates. There was a positive significant correlation between cord blood leptin level and birth length. There was no significant difference between neonates delivered by normal vaginal delivery and those by cesarean birth and no difference between male and female.
The lower cord blood leptin levels were seen to be associated with a lower birth weight, but with a more weight gain in early infancy.
Keywords: fat tissue, leptin, obesity
|How to cite this article:|
Mahmoud AT, El-Rafea Elbassuoni MA, Ellahony DM, Elmohsen Sheir SM. A study of serum leptin level in both full-term and preterm newborns. Menoufia Med J 2017;30:765-9
|How to cite this URL:|
Mahmoud AT, El-Rafea Elbassuoni MA, Ellahony DM, Elmohsen Sheir SM. A study of serum leptin level in both full-term and preterm newborns. Menoufia Med J [serial online] 2017 [cited 2020 Apr 5];30:765-9. Available from: http://www.mmj.eg.net/text.asp?2017/30/3/765/218284
| Introduction|| |
There is increasing interest in how the intrauterine environment might influence metabolic disease throughout life .
Following the discovery of the first protein–adipsin-secreted by adipocyte in 1987, researchers are paying closer attention to the endocrine functions of adipose cells, and they have isolated more than 20 bioactive substances. Among them, adiponectin, leptin, resistin, and tumor necrosis factor-α show important bioactivity in metabolism; in addition, they have shown a close relationship with leptin, and leptin is a key neuropeptide recognized by the brain for regulation of food intake and energy expenditure . This hormone, secreted by fat cells, acts on hypothalamic receptors to inhibit feeding, increasing thermogenesis . Leptin was found to be detectable in human fetal cord blood as early as 18th week of gestation, and its serum concentration was independent of maternal serum concentration of leptin . Leptin synthesis is stimulated by the hormones that regulate body energy homeostasis. Serum leptin levels of the newborn have been shown to decrease after birth. The rapid decrease of leptin levels after birth could be mediated by hormonal changes after birth . This was thought to be a physiologic advantage for newborns, especially for premature and small-for-gestational-age (SGA) babies, because energy supplies provided during intrauterine life were preserved in this way .
The accumulation of the body fat mass was reported as a major determinant of serum leptin levels in the fetus . Therefore, SGA and premature newborns have reduced serum leptin concentrations. The mode of delivery and diet, gestational age (GA), serum levels of insulin, glucocorticoids, resting metabolic rate, and sex were among other factors influencing the circulating serum leptin level in a study by Matsubara et al. .
Obesity results from an imbalance between food intake and energy expenditure, culminating in excessive accumulation of fat in adipose tissue, liver, muscle, pancreatic islets, and other organs involved in metabolism. Obesity increases the risk of diabetes, coronary artery disease, fatty liver, gall stones, sleep apnea, arthritis, and cancer and may shorten the life span . Human leptin has not been approved for any therapeutic use. Metreleptin, an analog of human leptin, is approved as a treatment for complications of leptin deficiency .
| Patients and Methods|| |
The umblical vein blood samples were withdrawn from 40 newborns over 1-month period; there were 20 females and 20 males. Their GA was 34–40 weeks. Inclusion criteria were any healthy full-term (GA ≥37 weeks) and preterm (GA <37 weeks) newborn. Exclusion criteria were newborns with signs of perinatal asphyxia, congenital anomalies, chromosomal disorders, congenital infection of any type, major placental lesion mechonium aspiration, newborn of hypertensive, and diabetic mother. Newborn babies were divided into two groups: group 1 included 30 full-term babies, who were subdivided into 10 appropriate for gestational age (AGA), 10 large for gestational age (LGA), and 10 SGA, and group 2 included 10 preterm infants. All babies were subjected to detailed history taking, including mother weight before and after pregnancy, and clinical examination, including baby weight and length. Investigation included cord serum leptin level (ng/ml) by enzyme-linked immunosorbent assay and follow-up for 3 months for weight gain. Informed consent was obtained from the parents of all children in our study. Ethical approval was taken for conducting this study from the Menoufia University Ethical Committee.
| Results|| |
In our study, we found that there was a positive significant correlation between cord blood leptin level and GA and weight. We also found that lower cord blood leptin levels were seen to be associated with lower birth weight but with more pronounced weight gain in first 3 months of life. During the follow-up of neonates, we found that weight gain was significantly higher in formula-feeding compared with breastfeeding neonates; this is explained by presence of leptin in human breast milk. There was a positive significant correlation between cord blood leptin and birth length. There was no significant difference between neonates delivered by normal vaginal delivery and those by cesarean birth and no significant difference in cord blood leptin in female than in male.
| Discussion|| |
The present study was designed to clarify the relationship between serum leptin and clinical data. Preterm infant group was compared with other infant groups (term-LGA, term-SGA, and term-AGA).
Umbilical vein blood samples were withdrawn from 40 newborns. The neonates selected were divided in two groups: preterm (25%) and full term (27%). The full-term newborns were subdivided into AGA (25%), LGA (25%), and SGA (25%).
In our study, the mean GA was 37 ± 1.58 weeks [Table 1].
In the current study, 20 (50%) of the studied neonates were male, whereas 20 (50%) were females.
The mean birth weight was 3.15 ± 0.79 kg in full-term group.
The mean birth weight in preterm group was 2.09 ± 0.12 kg.
Mean birth length was 49.1 ± 2.1 and 53.68 ± 4.57 cm which is comparable to our finding of 45.58 ± 2.17 cm, respectively [Table 1].
This study included 40 neonates. Their GAs ranged from 34 to 40 weeks, and their birth weights from 1.98 to 4.50 kg. According to GA and birth weight, they were divided into four groups. The GA and birth weight of the term-AGA group were 38.50 ± 0.53 weeks and 3.25 ± 0.21 kg, respectively; for term-LGA group were 38.80 ± 0.63 weeks and 4.03 ± 0.22 kg, respectively; for term-SGA group were 38.40 ± 0.52 weeks and 2.18 ± 0.08 kg, respectively; and for preterm-AGA group were 35.20 ± 3.60 weeks and 2.09 ± 0.12 kg, respectively.
Preterm infants group was compared with other infants groups (term-LGA, term-SGA, and term-AGA). Also the same parameters were correlated with serum leptin levels in cord blood in 'each group of infants.'
In our study, prepregnancy BMI was 23.80 ± 1.94 kg/m2, which is similar to the finding of Haugen et al.  who found that prepregnant BMI of parous mothers was 24.2 ± 4.2 kg/m2 [Table 1]. They found that certain maternal factors such as obesity may drive leptin level in both mothers and fetuses. This can be explained because maternal nutritional status has been shown to influence the birth weight of the offspring. In our study, we found that the infants who had higher cord blood leptin level had smaller change in weight gain throughout the period of the study  [Figure 1].
|Figure 1: Positive correlation and significant between BMI of mother (before) and serum leptin.|
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In the current study, the mean concentration of serum leptin level in cord blood in neonates was 7.05 ± 5.87 ng/ml [Table 1] which is nearly similar to that of Parker et al.  who found that the concentration of serum leptin in cord blood in neonates was 9.6 ± 6.6 ng/ml.
In this study, the infants who had higher cord blood leptin had smaller change in weight gain [Figure 2], [Figure 3], [Figure 4] throughout the period of the study.
|Figure 2: Positive correlation and significant between weight gain and serum leptin.|
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|Figure 3: Positive correlation and significant between weight gain (1–2 months) and serum leptin.|
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|Figure 4: Positive correlation and significant between weight gain (2–3 months) and serum leptin.|
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Cord blood leptin level was not significantly higher in female than in male in early childhood, which is supported by Karakosta et al. , who did not find differences in cord leptin levels according to sex. Our report is in contrast to the finding of Luo et al.. Furthermore, Helland et al.  suggested that these differences may reflect transient elevations in sex steroid levels because androgens are known to suppress and estrogens to promote leptin expressionin vitro andin vivo.
In our study, mode of delivery did not affect cord blood leptin level; this is in agreement withKirel et al. . It has been proposed that leptin is a stress-related hormone. Weight gain was significantly higher among those who were formula fed compared with those who were breastfed and mixed fed. This result disagrees with the finding of Treviño-Garza et al.  as they found that there were no differences in net weight gain between breastfed infants and formula-fed infants. However, it agrees with the finding of Barrenetxe and colleagues, which explains that the presence of leptin in human breast milk  may influence serum leptin levels in BF infants, exerting a role in short-term feeding regulation. Another study suggested that the hormone is not contained in formula owing to the pasteurization process it is subjected to  [Figure 4].
The same findings were obtained by Karakosta et al.  who state that umbilical cord leptin levels increase sharply with progressing GA and with increase mass of adipose tissue [Table 2], particularly from the 34th gestational week to term.
There was a positive significant correlation between cord leptin level and birth length [Table 2] and [Figure 5], which was supported by Marino-Ortega et al.  who found that cord blood leptin levels correlated with neonatal length [Table 2] and [Figure 5].
|Figure 5: Positive correlation and significant between body length and serum leptin.|
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There was a positive significant correlation between cord blood leptin level and birth weight. Our findings are supported byTreviño-Garza et al.  [Figure 6].
|Figure 6: Positive correlation and significant between weight and serum leptin.|
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| Conclusion|| |
From the result of our study we conclude thatcord blood leptin level seems to be a predictor of weight gain in early life. The lower cord blood leptin levels were seen to be associated with a lower birth weight but with a more weight gain in early infancy.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6]
[Table 1], [Table 2]