Expression of NO synthases and redox enzymes in umbilical arteries from newborns born small, appropriate, and large for gestational age

Serum adiponectin levels and adiponectin +276 G/T gene polymorphism in newborns with large and small birth weights

PURPOSE

Adiponectin may be an important indicator in the regulation of fetal and neonatal growth due to its metabolism, energy balance, and insulin-sensitizing action. The current study's goal was to determine if there is a link between adiponectin +276 G/T gene polymorphism and serum adiponectin level in newborns classified as appropriate for gestational age (AGA), small for gestational age (SGA), or large for gestational age (LGA).

METHODS

The study included newborns classified as AGA (n = 65), SGA (n = 65), or LGA (n = 65) according to their gestational age or birth weight. To determine the presence of adiponectin +276 G/T gene polymorphism, genotyping was done using polymerase chain reaction-restriction fragment length polymorphism. Enzyme-linked immunosorbent assay was used to determine the level of adiponectin in the blood.

RESULTS

The SGA newborns had significantly lower levels of serum adiponectin than the AGA and LGA newborns. There were statistically significant differences between the genotype frequencies (GG, GT, TT) of the SGA newborns (29.9%, 45.1%, 13.9%), the AGA newborns (41.6%, 20.7%, 44.4%), and the LGA newborns (28.6%, 34.1%, 41.7%) (chi-square = 15.8; degree of freedom = 4; p = .003). The newborns carrying the GT genotype had an increased risk of being SGA compared to those carrying the GG and TT genotypes (odds ratio [OR] = 3.07; confidence interval [CI] = 95% (1.38-6.64); p = .005 and OR = 6.96; CI = 95% (2.19-22.1); p < .001, respectively). The newborns carrying the GG and TT genotypes had better protection against being SGA than those carrying the GT genotype (OR = 0.33; CI = 95% (0.15-0.72); p = .005 and OR = 0.14; CI = 95% (0.05-0.46); p < .001, respectively). The newborns carrying the GT genotype had lower birth weights, head circumferences, and ponderal indices than those carrying the TT genotype (p < .001). The serum adiponectin levels between adiponectin +276 G/T genotypes did not differ significantly (p = .429). In addition, serum adiponectin level showed a significant positive correlation with birth weight, birth length, head circumference, and ponderal index in all newborns.

CONCLUSION

The results of the current study suggest that the adiponectin +276 G/T gene polymorphism was associated with an increased chance of being born SGA or LGA. The effect of this polymorphism on newborn birth size was independently associated with serum adiponectin levels. Adiponectin may play a role in fetal growth.

The incidence of NOS3 gene polymorphisms on newborns with large and small birth weight

The NOS3 gene polymorphisms T-786C, G894T and VNTR 4b/a are associated with a predisposition to the development of Metabolic Syndrome (MetS). The NOS3 gene contributes to a normal pregnancy and fetal development. According to their birthweight, newborns can be classified as: small (SGA), adequate (AGA) or large (LGA) for gestational age. The SGA and LGA present a higher risk of developing disorders related to MetS, both during childhood and adulthood. Therefore, the aim of this work is to relate the incidence of G894T, T-786C and VNTR 4b/a on SGA and LGA newborns and their mothers. 204 blood samples were collected from mothers (102) and the umbilical cords of 102 newborns (SGA = 12; AGA = 47; LGA = 43). The genotyping was performed through PCR-RFLP to evaluate presence of the G894T, T-786C and VNTR 4b/a polymorphisms. A significant difference was found between the groups of newborns in the genotypic frequency of T-786C, but without Hardy-Weinberg equilibrium. The VNTR 4b/a and the G894T polymorphisms showed no significance between the groups. The haplotype analysis showed that the SGA newborns presented the higher frequency of 4aGT (9.8%) and of the 4aTT combination (25.4%), while LGA newborns presented the higher frequency of the 4bTT haplotype (23%). Only the SGA newborns and their mothers presented the 4aTC haplotype. In conclusion, the NOS3 polymorphisms do not appear to be a factor to inadequate birth weight. However, the G894T and VNTR 4b/a polymorphisms, and the haplotype 4aTC, seem to influence the occurrence of SGA.

Endothelial dysfunction in individuals born after fetal growth restriction: cardiovascular and renal consequences and preventive approaches

Individuals born after intrauterine growth restriction (IUGR) have an increased risk of perinatal morbidity/mortality, and those who survive face long-term consequences such as cardiovascular-related diseases, including systemic hypertension, atherosclerosis, coronary heart disease and chronic kidney disease. In addition to the demonstrated long-term effects of decreased nephron endowment and hyperactivity of the hypothalamic-pituitary-adrenal axis, individuals born after IUGR also exhibit early alterations in vascular structure and function, which have been identified as key factors of the development of cardiovascular-related diseases. The endothelium plays a major role in maintaining vascular function and homeostasis. Therefore, it is not surprising that impaired endothelial function can lead to the long-term development of vascular-related diseases. Endothelial dysfunction, particularly impaired endothelium-dependent vasodilation and vascular remodeling, involves decreased nitric oxide (NO) bioavailability, impaired endothelial NO synthase functionality, increased oxidative stress, endothelial progenitor cells dysfunction and accelerated vascular senescence. Preventive approaches such as breastfeeding, supplementation with folate, vitamins, antioxidants, L-citrulline, L-arginine and treatment with NO modulators represent promising strategies for improving endothelial function, mitigating long-term outcomes and possibly preventing IUGR of vascular origin. Moreover, the identification of early biomarkers of endothelial dysfunction, especially epigenetic biomarkers, could allow early screening and follow-up of individuals at risk of developing cardiovascular and renal diseases, thus contributing to the development of preventive and therapeutic strategies to avert the long-term effects of endothelial dysfunction in infants born after IUGR.