Association of brain natriuretic peptide gene polymorphisms with chronic obstructive pulmonary disease complicated with pulmonary hypertension and its mechanism.

Objective: To examine the association between brain natriuretic peptide (BNP) gene single nucleotide polymorphisms (SNPs) and chronic obstructive pulmonary disease (COPD) and COPD with pulmonary hypertension (PH) and to analyze its mechanism. Methods: The genotypes of BNP at the rs198389, rs6668352, and rs198388 loci in 339 patients with COPD (205 in the COPD/PH- group and 134 in the COPD/PH+ group) and 125 healthy subjects were detected by PCR/Sanger sequencing. The serum levels of BNP, fibrinogen (Fbg), and Apelin were measured in all subjects by ELISA. Results: The BNP rs198389 locus G allele, rs6668352 locus A allele, and 198388 locus T allele were high risk factors for COPD ( P <0.001). Logistics regression analysis showed that BNP rs198389 locus G allele, rs6668352 locus A allele, and rs198388 locus T allele were high risk factors for PH in COPD patients (all P <0.001). The levels of the serum BNP and Fbg protein in the control group, COPD/PH- group, and COPD/PH+ group increased successively, and the expression levels of Apelin protein decreased successively (all P <0.001). The BNP and Fbg protein levels in the wild-type, heterozygote, and mutant homozygote in BNP rs198389, rs6668352, and rs198388 loci increased successively, and the serum Apelin protein levels decreased successively (all P <0.001). Conclusion: The polymorphisms of BNP at the rs198389, rs6668352, and rs198388 loci are associated with the occurrence of COPD and COPD with PH, and the occurrence may be related to the abnormal expression level of BNP, Fbg, and Apelin protein in the serum.