Background and aims Bronchopulmonary dysplasia (BPD) is an importantmorbidity in premature infants with an multifactorial aetiology. In recent years, both genetic and epigenetic mechanisms were suggested to play an important role in BPD development. NO (Nitric Oxide) which is produced along with L-Citrulline by the oxidation of L-Arginine and catalysed by three different isoforms of NOS (NOSynthase), is a short-lived free radical involved indiverse physiological and pathological processes. It consists of 3 types such as neuronal NOS, endothelial NOS and inducible NOS. All the NOS genes are expressed in airway epithelial cells and they are important for physiological functions in the airways. The aim of this study was to investigate possible association between eNOS gene polymorphism and development of BPD in preterm infants.
Methods One hundred and twenty two blood samples DNA isolation was carried out using the PureLinkTM Genomic DNA Mini Kit and the concentration of the DNA samples was measured by nanophotometerImplen P 300. For the SNP analysis of eNOS (rs1799983) optimised primers were used. Real Time Polymerase Chain Reaction (QRT-PCR) was carried out in a CFX96 thermocycler. Chi-square χ2 test, Fisher’s exact test, the odds ratio and confidence intervals were calculated for the comparisons of allelic and genotype frequencies.
Results Comparison of the allele frequency distribution revealed the presence of G allele as a highly significant risk factor for development of BPD (p = 0.000*; OR 4.07, 95% CI 2.066–8.009) compared to the T allele. The distribution of the T allele in eNOS was found to be similarly distributed amongst BPD (51.9%) and healthy control groups (48.1%). This study demonstrated that the frequency of the GG genotype (25.37%) of the eNOSgene was higher in babies with BPD rather than TT (53.6%) and TG (59.4)genotype, when these genotypes were compared with the healthy control groups. No healthy infants were seen to carry the GG genotype (p = 0.000*; OR 1.89, 95% CI 1.514–2.148). The TT genotype (p = 0.019*, OR 0.39, 95% CI 0.180–0.870) also displayed a susceptibility fordeveloping BPD. Heterozygous TG genotype (p = 0.631; OR 0.63, 95% CI 0.527–2.873) was not associated with the development of BPD.
Conclusion To our best of knowledge, noinvestigation of the eNOS gene polymorphism has previously been documented in BPD. Thefindings of this study demonstrated that the GG genotype in eNOS gene was highly significant for BPD.