Relationships between endothelial nitric oxide synthase gene polymorphisms and osteoporosis in postmenopausal women

Objective： To investigate the relationships between endothelial nitric oxide synthases （eNOS） G894T and 27 bpvariable number tandem repeat （VNTR） gene polymorphisms and osteoporosis in the postmenopausal women of Chinese Han nationality. Methods： In the present study, 281 postmenopausal women from Xi＇an urban area in West China were recruited, and divided into osteoporosis, osteopenia, and normal groups according to the diagnostic criteria of osteoporosis proposed by World Health Organization （WHO）. The bone mineral density （BMD） values of lumbar vertebrae and left hips were determined by QDR-2000 dual energy X-ray absorptiometry. Blood samples were tested for plasma biochemical indicators including testosterone, estradiol, calcitonin, osteocalcin, and procollagen type I amino-terminal propeptide by enzyme-linked immunosorbent assay （ELISA）, tartrate-resistant acid phosphatase by spectrophotometric method, and the content of nitric oxide by Griess method. Genome DNA was extracted from whole blood, and G894T polymorphism of eNOS gene was analyzed by using polymerase chain reaction-restriction fragment length polymorphism （PCR-RFLP） method and 27 bp-VNTR polymorphism of eNOS gene was genotyped by PCR method. Then the relationships between genotypes and biochemical indicators, genotypes and osteoporosis, and haplotypes and osteoporosis were analyzed. Results： The average BMD values of the femoral neck, ward＇s triangle and lumbar vertebrae 1-4 （LI-L4） in the subjects with T/T genotype in eNOS G894T locus were significantly higher than those in the subjects with G/T and G/G genotypes （P〈0.05）. The average BMD of the femoral neck in the subjects with a/a genotype of eNOS 27 bp-VNTR locus was evidently higher than that in the subjects with b/b genotype （P〈0.05）. The plasma testosterone and osteocalcin concentrations in the subjects of eNOS G894T G/T genotype were evidently higher than those in the subjects of other genotypes （P〈0.05）; the plasma estradiol concentration in the subjects of eNOS 27 bp-VNTR a/a genotype was obviously higher than that in the subjects of b/b genotype （P〈0.01）. eNOS G/G homozygous frequencies in osteoporosis women, osteopenia women, and normal women were 85.37%, 76.38%, and 83.87%, respectively （P〉0.05）. 0% osteoporosis woman, 0.79% osteopenia women, and 3.23% normal women were eNOS a/a homozygous （P〈0.05）. The frequencies of eNOS 27 bp-VNTR a allele were 5.33% in the osteoporosis group, 10.24% in the osteopenia group, and 16.13% in the normal group （P〈0.05, odds ratio （OR）=0.29, 95% confidence interval （CI）=0.11-0.77）, suggesting that a/a genotype and a allele might have protective effects on osteoporosis. The haplotype analysis showed that G-b was 87.7% （214/244） in the osteoporosis group （P〈0.05, OR=2.48, 95% CI=1. 18-5.18）. G-a was 5.3% （13/244） in the osteoporosis group （P〈0.05, OR=0.29, 95% CI=0. 11-0.77）. G-b was a risk factor for osteoporosis, and G-a a protective factor. Conclusion： eNOS G894T G/T genotype influenced the plasma testosterone and osteocalcin concentrations, and T/T genotype influenced BMD. eNOS 27 bp-VNTR a/a genotype increased plasma estradiol concentration to have a protective effect on osteoporosis.

Distributions of HLA-A and-B alleles and haplotypes in the Yi ethnic minority of Yunnan, China: relationship to other populations

Objective: To investigate the distributions of human leukocyte antigen (HLA)-A and-B alleles and HLA-A-B haplotypes in the Yi ethnic minority of the Yunnan Province, situated in southwestern China. Methods: DNA typing for HLA-A and-B loci was performed using the polymerase chain reaction-sequence-based typing (PCR-SBT) method on 114 randomly selected healthy individuals of the Yi population. The allelic frequencies of HLA-A and-B loci were calculated by direct counting and HLA-A-B haplotypes were estimated using the expectation maximization algorithm. Results: A total of 17 HLA-A and 38 HLA-B alleles were found in the Yi population. The most frequent alleles were A2402 (32.46%), A1101 (26.32%), and A0203 (10.09%) at the HLA-A locus and B4601 (12.28%), B1525 (10.09%), B4001 (8.77%), and B3802 (7.89%) at the HLA-B locus. The predominant HLA-A-B haplotypes were A2402-B1525 (7.86%) and A0203-B3802 (5.64%), followed by A1101-B4001 (4.69%). Phylogenetic analysis indicates that the Yi population in the Honghe, Yunnan Province of China basically belongs to groups of southeastern Asian origin, but shares some characteristics with northeastern Asian groups. Conclusion: The present study may add to the understanding of HLA polymorphism in the Yi ethnic group that was poorly defined previously, and provide useful information for bone marrow transplantation, anthropological research, and forensic sciences as well as for disease-association studies.