Is there a relationship between endothelial nitric oxide synthase gene polymorphisms and ankylosing spondylitis?

OBJECTIVE: Nitric oxide is produced by endothelial nitric oxide synthase, and its production can be influenced by polymorphisms of the endothelial nitric oxide synthase gene. Because candidate genes responsible for susceptibility to ankylosing spondylitis are mostly unknown and available data suggest that there may be problems related to the nitric oxide pathway, such as endothelial dysfunction and increased asymmetric dimethylarginine, this study aimed to assess the association of common endothelial nitric oxide synthase gene polymorphisms with ankylosing spondylitis. METHODS: One hundred ninety-four unrelated Turkish ankylosing spondylitis patients and 113 healthy without apparent cardiovascular disease, hypertension or diabetes mellitus were included. All individuals were genotyped by PCR-RFLP for two single-nucleotide polymorphisms, namely 786T>C (rs2070744, promoter region) and 786 Glu298Asp (rs1799983, exon 7). Variable numbers of tandem repeat polymorphisms in intron 4 were also studied and investigated by direct electrophoresis on agarose gel following polymerase chain reaction analysis. The Bath ankylosing spondylitis metrology index of the patients was calculated, and human leukocyte antigen B27 was studied. RESULTS: All studied polymorphisms satisfied Hardy-Weinberg equilibrium. Sex distributions were similar between the patient and control groups. No significant differences were found in the distributions of allele and genotype frequencies of the studied endothelial nitric oxide synthase polymorphisms between patients and controls. There were no correlations between endothelial nitric oxide synthase polymorphisms, disease duration, Bath ankylosing spondylitis metrology index or human leukocyte antigen B27. CONCLUSION: The results presented in this study do not support a major role of common endothelial nitric oxide synthase polymorphisms in Turkish ankylosing spondylitis patients.

Evaluation of serum paraoxonase and arylesterase activities in ankylosing spondylitis patients

OBJECTIVES: The aim of this study was to investigate the activities of serum paraoxonase and arylesterase in patients with ankylosing spondylitis with respect to those of healthy controls, to assess whether these enzyme levels are related to disease activity and functional capacity. METHODS: The study included 32 patients with ankylosing spondylitis whose diagnoses were made according to the modified New York criteria as well as 25 healthy controls matched for age and sex. The Bath Ankylosing Spondylitis Disease Activity Index and the Bath Ankylosing Spondylitis Functional Index were applied to the ankylosing spondylitis patients. As laboratory parameters, the erythrocyte sedimentation rate and serum C-reactive protein level were measured in patients and control subjects. Paraoxonase and arylesterase enzyme activities were measured using appropriate methods. RESULTS: No statistically significant differences (p>0.05) were found between the ankylosing spondylitis patients and controls in terms of serum paraoxonase or arylesterase levels. Furthermore, there was no correlation between clinical and laboratory parameters in patients with ankylosing spondylitis. CONCLUSION: Serum paraoxonase and arylesterase levels in ankylosing spondylitis patients may not differ from those of healthy controls, and there is no significant correlation between antioxidant parameters and the Bath Ankylosing Spondylitis Disease Activity Index or Bath Ankylosing Spondylitis Functional Index scores in ankylosing spondylitis patients. Further research is needed to provide deeper understanding of this disease.