Ghrelin levels in cord blood from concordant and discordant twin pairs: association with birth weight and postnatal catch-up growth

Blood Acylated Ghrelin Concentrations in Healthy Term Newborns: A Prospective Cohort Study

Objective

The effect of ghrelin, a growth hormone (GH) secretagogue on growth of neonates, has been studied in the past, but not fully clarified. We aimed to investigate the relationship between ghrelin and growth parameters at birth and at the age of three months in healthy term infants. Methodology. This was a prospective observational study carried out in a tertiary care hospital. Eighty-four infants born at gestational ages between 37 and 42 weeks and classified as term small for gestational age (SGA) and appropriate for gestational age (AGA) were included in the study. Estimation of acylated ghrelin (AG) concentrations was done in the cord blood at birth and in venous blood at the age of 3 months in all the infants. The correlation between AG concentrations and growth parameters at birth and at 3 months was studied.

Results

AG concentrations were significantly higher in SGA (236.16 ± 152.4 pg/ml) than AGA neonates (59.45 ± 20.95 pg/ml) at birth. Concentrations were observed to be negatively correlated with birth weight (r = −0.34, p value 0.03), birth length, and head circumference (r = −0.509 and -0.376, respectively) in SGA neonates. However, at 3 months, AG concentrations did not correlate with changes in anthropometric parameters in both the groups.

Conclusion

Cord acylated ghrelin concentrations are higher in SGA neonates, and the concentrations are inversely proportional to the birth weight. Hence, its role as a surrogate marker for intrauterine nutrition can be suggested. However, its concentrations do not correlate with anthropometric parameters in early postnatal growth, suggesting it may not have a direct role in postnatal growth.

Association of cord blood ghrelin, leptin and insulin concentrations in term newborns with anthropometric parameters at birth

BACKGROUND

Ghrelin, leptin and insulin, generally considered as regulators of energy homeostasis of the organism may be related to fetal and early postnatal growth. Numerous studies have confirmed the presence of these hormones in the cells of the fetus indicating their importance in development at early stages of life.

METHODS

This study analyzed active and total ghrelin by radioimmunoassay (RIA), leptin and insulin concentrations by enzyme-linked immunosorbent assay (ELISA) in 65 cord blood samples, from term newborns, and measured the birth anthropometric parameters [birth weight (BW), head circumference, chest, stomach, thigh and arm circumference].

RESULTS

Active ghrelin (AG) concentrations correlated negatively with BW, head circumference, stomach and thigh circumference. When divided by gender, AG correlated negatively with males' BW, stomach and thigh circumference. Females' head circumference correlated negatively with AG. Cord leptin correlated positively with arm circumference. When divided by gender, cord leptin was positively associated with BW and stomach circumference in male newborns and with thigh and arm circumference in female newborns. Insulin concentrations tended to correlate positively with BW in male newborns.

CONCLUSIONS

In summary, it was confirmed that cord blood ghrelin, leptin and insulin correlate with anthropometric parameters at birth. This study showed a negative correlation of AG with anthropometric parameters, which may emphasize that this hormone is an indicator of growth restriction. This is in contrast to cord leptin and insulin, which are more connected with overgrowth. Taking all the results into consideration, the metabolic status of the fetus and newborn is an essential component in understanding the regulation of perinatal development.

Comparison of umbilical cord ghrelin concentrations in full-term pregnant women with or without gestational diabetes

PURPOSE

Ghrelin is a potent orexigenic peptide hormone secreted from the gastrointestinal tract that plays a crucial role in the regulation of lipids and glucose metabolism. Ghrelin also has links with fetal development and growth. Gestational diabetes mellitus (GDM) causes fetal macrosomia, but there is no available evidence of a relationship between ghrelin levels and birth weight in women with GDM. The purpose of this study is to investigate whether umbilical cord ghrelin concentrations are altered in full-term pregnant women with GDM compared to women without GDM and whether birth weight is correlated with ghrelin levels.

MATERIALS AND METHODS

Sixty pregnant women with GDM and 64 healthy pregnant women without GDM were included in this cross-sectional study. Blood samples were drawn from the umbilical vein following birth. Ghrelin concentrations were measured using enzyme-linked immunosorbent assay (ELISA).

RESULTS

Umbilical vein ghrelin levels were decreased in women with GDM (879.6 ± 256.1 vs. 972.2 ± 233.6 pg/ml in women without GDM, p=0.033), whereas birth weights were higher for babies in the GDM than in the non-GDM group (3448 ± 410 vs. 3308 ± 365 gr, respectively, p=0.046). Umbilical ghrelin levels were inversely correlated with birth weight (r=-0.765, p<0.001). Multiple regression analysis revealed that birth weight was independently and negatively associated with umbilical ghrelin levels (β= -2.077, 95% CI=-2.652 to -1.492, p=0.002).

CONCLUSIONS

Umbilical ghrelin levels were lower in GDM women. Birth weight was inversely associated with umbilical ghrelin levels. This association may be explained by a negative feedback mechanism between ghrelin and birth weight.