Ghrelin levels are decreased in non-obese prepubertal children born large for gestational age

The association between serum ghrelin levels and large-for-gestational-age fetuses in patients with gestational diabetes mellitus

We aimed to determine the relationship between serum ghrelin levels and large-for-gestational-age (LGA) fetuses in patients with gestational diabetes mellitus (GDM). A case-control study was conducted in 32 women with GDM and LGA fetuses (GDM + LGA group), 35 women with GDM and appropriate-for-gestational-age (AGA) fetuses (GDM + AGA group), 32 women with normal glucose tolerance (NGT) and LGA fetuses (NGT + LGA group), and 31 women with NGT and AGA fetuses (NGT + AGA group). All participants were recruited at the time of GDM diagnosis between 24 and 30 weeks of pregnancy. Participants also underwent ultrasonographic examinations. Serum ghrelin levels were significantly higher in GDM + LGA and GDM + AGA groups than in the NGT + AGA group. In the univariate model, biparietal diameter, head circumference, abdominal circumference (AC), femur length and ghrelin values were significant predictors of LGA fetuses. In the multivariate model, only AC remained as a predictor of LGA fetuses.

Association of cord blood des-acyl ghrelin with birth weight, and placental GHS-R1 receptor expression in SGA, AGA, and LGA newborns

Although ghrelin in cord blood has been associated to birth weight, its role in fetal and postnatal growth has not been elucidated. The aim of this study was to analyze total ghrelin, acyl ghrelin (AG), and des-acyl ghrelin (DAG) in cord blood of newborns with idiopathic birth weight alterations, and to evaluate protein expression of placental GHS-R1, in order to investigate their correlation with birth weight and placental weight. We performed a cross-sectional comparative study in umbilical cord blood and placentas from healthy mothers of SGA, AGA, and LGA (small, adequate and large for gestational age) term newborns (n = 20 per group). Cord blood total ghrelin, AG, and DAG were measured by ELISA, and placental GHS-R1 expression was evaluated by Western blot. Cord blood DAG was higher in SGA compared to AGA newborns (902.1 ± 109.1 and 597.4 ± 58.2 pg/ml, respectively, p = 0.01) while LGA and AGA showed similar values (627.2 ± 76.4 pg/ml for LGA, p = 0.80). DAG negatively correlated with birthweight (r = -0.31, p = 0.02) and placental weight (r = -0.33, p = 0.02). No differences in AG or total ghrelin were found. GHS-R1 protein in placenta was not differentially expressed among SGA, AGA, and LGA. Our results suggest a role of DAG in intrauterine growth. Further studies are needed in order to elucidate the mechanisms by which DAG participates in fetal growth.

Early growth and postprandial appetite regulatory hormone responses

Strong epidemiological evidence suggests that slow prenatal or postnatal growth is associated with an increased risk of CVD and other metabolic diseases. However, little is known whether early growth affects postprandial metabolism and, especially, the appetite regulatory hormone system. Therefore, we investigated the impact of early growth on postprandial appetite regulatory hormone responses to two high-protein and two high-fat content meals. Healthy, 65–75-year-old volunteers from the Helsinki Birth Cohort Study were recruited; twelve with a slow increase in BMI during the first year of life (SGI group) and twelve controls. Subjects ate a test meal (whey meal, casein meal, SFA meal and PUFA meal) once in a random order. Plasma glucose, insulin, TAG, NEFA, ghrelin, peptide tyrosine-tyrosine (PYY), glucose-dependent insulinotropic peptide, glucagon-like peptide-1 and a satiety profile were measured in the fasting state and for 4 h after each test meal. Compared with the controls, the SGI group had about 1·5-fold higher insulin responses after the whey meal (P= 0·037), casein meal (P= 0·023) and PUFA meal (P= 0·002). TAG responses were 34–69 % higher for the SGI group, but only the PUFA-meal responses differed significantly between the groups. The PYY response of the SGI group was 44 % higher after the whey meal (P= 0·046) and 115 % higher after the casein meal (P= 0·025) compared with the controls. No other statistically significant differences were seen between the groups. In conclusion, early growth may have a role in programming appetite regulatory hormone secretion in later life. Slow early growth is also associated with higher postprandial insulin and TAG responses but not with incretin levels.

Cord ghrelin levels are decreased in large-for-gestational-age neonates

Ghrelin is a growth hormone secretagogue peptide and has been recognized as an orexigenic factor. To investigate relationship between cord ghrelin and anthropometric and metabolic indices, we measured cord ghrelin in large-for-gestational-age (LGA) and appropriate-for-gestational-age (AGA) neonates and examined whether cord ghrelin levels were correlated to concentrations of cord blood glucose, insulin, lipid and maternal ghrelin. Fifty-five singletons born at term and their mothers were investigated in this study. Maternal venous blood samples were collected before delivery. Plasma concentrations of ghrelin, insulin, glucose, total cholesterol, triacylglycerol (TG), low-density lipoprotein-cholesterol (LDL-C) and high-density lipoprotein-cholesterol were measured in cord blood sampled at birth. The results show that the concentrations of cord ghrelin are significantly lower in LGA neonates. There is a positive correlation between cord ghrelin levels and maternal ghrelin levels. Negative correlations are found between cord ghrelin levels and gestational age, the concentrations of cord glucose, insulin, TG and LDL. Multivariate regression analyses show that birth weight (r(2)  = 0.674, β = -0.548, P < 0.001) was the predictor correlating with ghrelin levels. In conclusion, LGA neonates have lower cord ghrelin concentrations than AGA neonates.

AMPK as Target for Intervention in Childhood and Adolescent Obesity

Childhood obesity is a major worldwide health problem. Intervention programs to ameliorate the rate of obesity have been designed and implemented; yet the epidemic has no end near in sight. AMP-activated protein kinase (AMPK) has become one of the most important key elements in energy control, appetite regulation, myogenesis, adipocyte differentiation, and cellular stress management. Obesity is a multifactorial disease, which has a very strong genetic component, especially epigenetic factors. The intrauterine milieu has a determinant impact on adult life, since the measures taken for survival are kept throughout life thanks to epigenetic modification. Nutrigenomics studies the influence of certain food molecules on the metabolome profile, raising the question of an individualized obesity therapy according to metabolic (and probably) genetic features. Metformin, an insulin sensitizing agent, its known to lower insulin resistance and enhance metabolic profile, with an additional weight reduction capacity, via activation of AMPK. Exercise is coadjutant for lifestyle modifications, which also activates AMPK in several ways contributing to glucose and fat oxidation. The following review examines AMPK's role in obesity, applying its use as a tool for childhood and adolescent obesity.