Endothelial nitric oxide synthase gene polymorphisms in giant cell arteritis

OBJECTIVE: To examine potential associations of the Glu/Asp(298) polymorphism in exon 7 and the 4a/b polymorphism in intron 4 of the endothelial nitric oxide synthase (eNOS) gene with susceptibility to and clinical expression of giant cell arteritis (GCA), particularly in patients with versus those without ischemic complications. METHODS: Ninety-one consecutive patients with biopsy-proven GCA, who were residents of Reggio Emilia, Italy, and 133 population-based controls from the same geographic area were genotyped by polymerase chain reaction and allele-specific oligonucleotide techniques for eNOS polymorphisms in exon 7 and intron 4. The patients were separated into 2 subgroups according to the presence or absence of ischemic complications (visual loss and/or jaw claudication and/or aortic arch syndrome). RESULTS: The distribution of the Glu/Asp(298) genotype differed significantly between GCA patients and controls (corrected P [P(corr)] = 0.003). Carriers of the Asp(298) allele (Asp/Asp or Glu/Asp) were significantly more frequent among the GCA patients than among the controls (P(corr) = 0.0002, odds ratio 3.3, 95% confidence interval 1.7-6.3). The distribution of the 4a/b genotype was similar in GCA patients and controls. No significant associations were found when GCA patients with and without ischemic complications were compared. CONCLUSION: Our findings show that the Glu/Asp(298) polymorphism of the eNOS gene is associated with GCA susceptibility.     

Association of a functional inducible nitric oxide synthase promoter variant with susceptibility to biopsy-proven giant cell arteritis

OBJECTIVE: To assess the contribution of 2 polymorphisms within the inducible nitric oxide (NOS2A) promoter region to susceptibility to giant cell arteritis (GCA). METHODS: One hundred three patients with biopsy-proven GCA and 198 ethnically matched controls from the Lugo region (Northwest Spain) were studied. Patients and controls were genotyped using polymerase chain reaction techniques for a multiallelic (CCTTT)n and for the TAAA repeat polymorphism in the promoter region of the NOS2A gene. RESULTS: No significant differences in allele or genotype frequencies for the (CCTTT)n repeat polymorphism in the NOS2A gene between patients with GCA and controls were observed. However, significant differences for the TAAA repeat polymorphism between patients and controls were found. The overall distribution of NOS2A TAAA genotypes in patients with biopsy-proven GCA was significantly different than controls (p = 0.026). Patients with GCA had an increased frequency of the NOS2A TAAA+ allele (16.5%) compared with controls (9.1%) (p = 0.007; OR 1.98; 95% CI 1.20-3.27). This was due to an increased frequency of both heterozygotes (27.2%) and homozygotes (2.9%) for NOS2A TAAA+ observed in patients compared to controls (15.2% and 1.5%, respectively) (p = 0.007; OR 2.15; 95% CI 1.23-3.78). CONCLUSION: Our results suggest a potential implication for NOS2A TAAA gene polymorphism in GCA susceptibility.     

Endothelial nitric oxide synthase polymorphisms in biopsy-proven erythema nodosum from a defined population

OBJECTIVE: To assess the potential in-fluence of endothelial nitric oxide synthase (eNOS) polymorphisms in the susceptibility to and clinical expression of a series of patients diagnosed with biopsy-proven erythema nodosum (EN). METHODS: Ninety-seven unselected patients from Northwest Spain with biopsy-proven EN were studied. Patients and ethnically matched controls were genotyped by PCR based techniques for a variable number tandem repeat polymorphism in intron 4, a T/C polymorphism at position -786 in the promoter region and a polymorphism in exon 7 (298Glu/Asp or 5557G/T) of the eNOS gene. RESULTS: No differences in allele or genotype frequencies for any of the individual eNOS polymorphisms were observed between biopsy-proven patients with EN and controls. It was also the case when patients with EN secondary to sarcoidosis were compared with the remaining patients or controls. In the group of patients with EN, no linkage disequilibrium between these polymorphisms was found. Also, no significant differences in haplotype frequencies were observed between patients and controls. CONCLUSION: Our present results do not support a role for eNOS polymorphisms in the susceptibility to and clinical expression of EN.     

Atherosclerosis in patients with biopsy-proven giant cell arteritis

OBJECTIVE: To examine the presence of atherosclerosis in a series of giant cell arteritis (GCA) patients attended to in a community hospital and to determine whether clinical features or steroid therapy might be associated with the development of atherosclerotic disease. METHODS: Forty consecutive patients diagnosed with biopsy-proven GCA, periodically followed at the rheumatology outpatient clinic of Hospital Xeral-Calde, Lugo (Spain), who had ended steroid therapy and had at least 3 years of followup were assessed for the presence of atherosclerosis by determination of the carotid intima-media thickness (IMT) and carotid plaques using high-resolution B-mode ultrasound. Forty matched controls were also studied. RESULTS: GCA patients exhibited less carotid artery IMT than did matched controls (mean +/- SD 1.01 +/- 0.16 mm versus 1.13 +/- 0.20 mm; P = 0.005; difference in means 0.12, 95% confidence interval 0.04-0.20). Patients who required steroid therapy for >2 years had greater mean +/- SD carotid IMT (1.04 +/- 0.17 mm versus 0.95 +/- 0.15 mm) but the difference was not statistically significant (P = 0.10). A positive correlation between age at the time of the study and the carotid artery IMT in GCA patients was observed (r = 0.673, P < 0.001). However, adjusting for age, sex, and classic atherosclerosis risk factors, no significant correlation between carotid IMT and the routine laboratory markers of inflammation assessed at the time of disease diagnosis, disease duration, or cumulative prednisone dose was found. CONCLUSION: The present study demonstrates that atherosclerotic macrovascular disease is not increased in patients with GCA.     

Endothelial nitric oxide synthase gene haplotype association with systemic lupus erythematosus

Endothelial nitric oxide synthase (eNOS) catalyses the production of nitric oxide, which has been shown to participate in the pathogenesis of systemic lupus erythematosus (SLE). eNOS gene polymorphism may have an effect on eNOS gene expression, eNOS protein synthesis and enzymatic activity. We investigated the influence of eNOS gene polymorphisms on susceptibility to SLE. eNOS T-786C, G894T and intron 4 27-base pair tandem repeat (VNTR4) polymorphisms were investigated in 152 SLE patients and 184 controls using RFLP-PCR, direct sequencing and fragment analysis. Allele, genotype and haplotype frequency comparisons, Hardy-Weinberg equilibrium and linkage disequilibrium (LD) analysis were performed. No significant association was detected between SLE and single-nucleotide polymorphisms (SNPs) T-786C and G894T. VNTR4 allele 4b was associated with susceptibility to SLE (OR 1.89, p?=?0.023), as was the genotype 4bb (OR 2.41, p?=?0.007). However, allele 4a was protective (OR 0.53, p?=?0.023), as was genotype 4ab (OR 0.41, p?=?0.007). T-786C and VNTR4 were in high LD (r (2?)=?0.34). Haplotypes T4bC and C4aG of the three tested polymorphisms had a susceptibility effect on SLE (OR 1.89 and 4.23 at p?=?0.005 and 0.001, respectively), while haplotypes T4aG and C4bG had a protective effect (OR 0.06 and 0.11 at p?=?0.000001 and 0.0005, respectively). The novel finding in our study is that individual eNOS polymorphisms probably do not exert a major influence on susceptibility to SLE, but they have significant effects when combined within a specific haplotype.     

Epidemiology of biopsy-proven giant cell arteritis (GCA)

Abstract. During a 10-year period from 1st January 1977 to 31st December 1986, a temporal artery biopsy was performed in 2307 patients in the city of Göteborg. The biopsy revealed giant cell arteritis (GCA) in 284 (12.5%) of patients. The average annual incidence of biopsy-proven GCA was 6.7 per 100 000 inhabitants. For women and men it was 9.9 and 3.5 per 100 000 inhabitants, respectively. In individuals aged 50 years or older, the average incidence was 18.3 per 100 000 inhabitants, with values of 25 and 9.4 for women and men, respectively. The annual incidence rate increased significantly (P < 0.01) for women, but not for men: this result was not explained by demographic changes in the population.     

Cancer in biopsy-proven giant cell arteritis. A population-based study

OBJECTIVE: To investigate the potential association between giant cell arteritis (GCA) and cancer in a series of consecutive patients diagnosed with biopsy-proven GCA over a 25-year period at the single reference hospital for a well-defined population. METHODS: The case records of all patients diagnosed with biopsy-proven GCA at the Department of Medicine of the Hospital Xeral-Calde (Lugo, Northwest Spain) between January 1, 1981 and December 31, 2005 were reviewed. Information on cancer and cause of death over the extended follow-up was assessed. In all cases the presence of cancer was histologically confirmed. RESULTS: Cancer was found in 39 (15.3%) of the 255 GCA patients. Although 7 (18%) of the 39 patients had cancer either at the time or within the first 12 months after GCA diagnosis, the standardized mortality ratio (SMR) due to cancer in patients with biopsy-proven GCA showed no increase (overall SMR 1.06 [0.65-1.60]; men, 0.81; women, 1.50). The time interval between GCA diagnosis and cancer diagnosis was 5.2+/-3.8 years (median 4.2 years; interquartile range: 3-7 years). When multivariate analysis adjusted by age and sex was performed, only the presence of dysphagia (adjusted hazards ratio (HR)=3.90; P=0.04), abnormal temporal artery on physical examination (adjusted HR=4.61; P=0.04), and anemia at the time of GCA diagnosis (adjusted HR=3.39; P=0.01) were associated with an increased risk of cancer over the extended follow-up. CONCLUSION: The results from this series do not support an overall increase of mortality due to cancer in GCA.     

Steroid therapy improves endothelial function in patients with biopsy-proven giant cell arteritis

OBJECTIVE: Endothelial dysfunction has been found to be present in subjects with both small and medium-size blood vessel vasculitides. We assess whether endothelial dysfunction was also present in patients with biopsy-proven giant cell arteritis (GCA) and whether it might be improved following steroid treatment. METHODS: Endothelial function was determined in cross-sectional and longitudinal studies of 6 patients with biopsy-proven GCA diagnosed between January and May 2002 by measuring flow-mediated endothelial-dependent and independent vasodilatation (EDV and EIV) by brachial ultrasonography. Patients were assessed for endothelial function within 48 hours after the onset of steroid therapy, 4 weeks after the onset of steroid therapy, and 2 years after the disease diagnosis. RESULTS: EDV was significantly impaired in patients with GCA compared with 12 matched controls [mean 2.9%, median 2.45% (range 2.1% to 4.7%) vs mean 6.5%, median 6.6% (range 3.9% to 9.3%) in matched controls; p = 0.002]. However, no significant difference existed between patients and controls in EIV. Significant improvement of EDV after the suppression of inflammation was achieved. At Week 4 after the onset of steroid therapy all 6 patients showed enhanced responses (p = 0.028). This improvement of EDV was still present when steroid treatment was ended, 2 years after diagnosis. CONCLUSION: Endothelial function is significantly impaired in individuals with active biopsy-proven GCA. The results highlight the importance of steroid therapy to improve endothelial function after suppression of the inflammation of GCA.     

Endothelial nitric oxide synthase and endothelial dysfunction

Nitric oxide (NO) regulates vascular tone and local blood flow, platelet aggregation and adhesion, and leukocyte-endothelial cell interactions. Abnormalities in NO production by the vascular endothelium result in endothelial dysfunction, which occurs in hypertension, diabetes, aging, and as a prelude to atherosclerosis. The common feature of endothelial dysfunction is a decrease in the amount of bioavailable NO. In this article, the physiologic roles of NO and the mechanisms of endothelial dysfunction are reviewed. Regulation of endothelial NO synthase (eNOS) activity by fatty acid modifications, intracellular localization, interactions with heat shock protein 90 (hsp90) and caveolin, substrate and cofactor dependence, and phosphorylation might all affect the level of bioavailable NO. A hypothesis is proposed that the final common pathway of diverse causes of endothelial dysfunction involves abnormalities in eNOS phosphorylation at Ser 1179 and other key phosphorylation sites     

Endothelial nitric oxide synthase polymorphisms and hypertension

The human endothelial nitric oxide synthase (eNOS) gene is highly polymorphic. Evidence for the involvement of eNOS single nucleotide polymorphisms in the development of essential hypertension is limited, though the eNOS Glu298Asp polymorphism appears to influence the blood pressure response to exercise. This variant also influences endothelial function, with its effects becoming manifest during the adaptive vascular changes of pregnancy. Carriers of eNOS Asp298 may be at risk of developing pre-eclampsia. Molecular studies have indicated that intact eNOS Asp298 has equivalent enzymatic activity to eNOS Glu298, but undergoes selective proteolysis in native cells and tissues such that the steady state level of active eNOS may be reduced in carriers of this allele. Carriers of eNOS Asp298, particularly if exposed to adverse environmental infuences on endothelial function, may be at increased risk of developing atherosclerosis and cerebrovascular disease.     

Fever in biopsy-proven giant cell arteritis: clinical implications in a defined population

OBJECTIVE: To assess the frequency and clinical features of biopsy-proven giant cell arteritis (GCA) patients who had fever at the time of diagnosis of the disease, and the relationship between fever, ischemic complications, and the systemic inflammatory response in GCA. METHODS: A retrospective study of biopsy-proven GCA patients diagnosed between 1981 and 2001 was performed at the single referral hospital for a well-defined population in the Lugo region of northwest Spain. Patients were considered as having fever if the axillary temperature at the time of admission or during the followup prior to the onset of corticosteroid therapy was > or =38 degrees C. RESULTS: During the period of study, 21 (10%) of the 210 biopsy-proven GCA patients had fever. Two of them fulfilled criteria for fever of unknown origin. Patients with fever had a lower frequency of severe ischemic manifestations than the rest of biopsy-proven GCA patients. They also exhibited a more severe inflammatory disease, with significant abnormality in most laboratory variables, including higher elevation of erythrocyte sedimentation rate, lower values of hemoglobin, and higher proportion of patients with increased alkaline phosphatase. By logistic regression analysis, we observed that patients with fever had an increased risk of developing anemia (odds ratio [OR] 12.24). In contrast, a negative association between severe ischemic manifestations and fever was found (OR 0.41). CONCLUSION: Biopsy-proven GCA patients with fever constitute a subgroup of patients with more severe inflammatory response and less ischemic disease.     

MCP-1 gene haplotype association in biopsy proven giant cell arteritis

OBJECTIVE: Giant cell arteritis (GCA) is the most frequent vasculitis in European and North American countries. Increased expression of monocyte chemoattractant protein 1 (MCP-1) has been observed within the inflammatory infiltrates of blood vessels and serum of patients with GCA and in other autoimmune and inflammatory conditions. MCP-1 gene polymorphisms have been reported to contribute to susceptibility to several immune and inflammatory conditions. To investigate the clinical implication of MCP-1 polymorphisms in GCA, we examined the association of 3 single nucleotide polymorphisms (SNP) in a series of patients with GCA from Northwest Spain. METHODS: Seventy-nine patients with biopsy proven GCA and 99 ethnically matched controls were studied. Patients and controls were genotyped for MCP-1 polymorphisms. SNP included in this study (rs2857657, rs4586, rs139000) were located in intron 1(G/C), exon 2(T/C), and 3'UTR(C/T) region of MCP-1 gene. RESULTS: The distribution of the alleles and genotypes for each MCP-1 polymorphism showed no significant differences between GCA patients and controls. When we compared the overall distribution of haplotype frequencies between GCA cases and controls a significant difference was observed (p = 0.005, by chi-square test from 4 2 contingency table). In addition, haplotype C-C was significantly increased in GCA patients compared with controls (p = 0.03, OR 2.09, 95% CI 1.09-4.02). Similarly, haplotype T-T was overrepresented in GCA patients (p = 0.005). CONCLUSION: Significant differences in haplotype frequencies between GCA patients and controls may indicate a role for MCP-1 gene in susceptibility to GCA.     

Association of CD24 gene polymorphisms with susceptibility to biopsy-proven giant cell arteritis

OBJECTIVE: To investigate the possible implication of CD24 gene in the genetic predisposition to giant cell arteritis (GCA). METHODS: A total of 120 patients diagnosed with biopsy-proven GCA and 195 ethnically matched controls from the same region were studied. Two putative functional polymorphisms, a C to T coding polymorphism (rs8734) and a TG deletion in the 3' untranslated region (rs3838646) were used as CD24 genetic markers and genotyped using a Taqman 5' allelic discrimination assay. RESULTS: The 2 genetic variants showed statistically significant differences between patients with GCA and controls. The strongest association was observed for the rs3838646 TG/del polymorphism, conferring on the "del" allele an increased risk of GCA genetic susceptibility (odds ratio 1.94, 95% confidence interval 1.15-3.27, p = 0.01). In addition, genotypes carrying the rs3838646 "del" allele showed an increased frequency among GCA patients compared to controls (OR 2.31, 95% CI 1.30-4.1, p = 0.003). For the rs8743, an increased frequency of Val/Val homozygous individuals in patients with GCA compared to controls (OR 6.08, 95% CI 1.50-24.63, p = 0.001) was observed. A high degree of linkage disequilibrium was estimated between the 2 polymorphisms (D' = 0.7) and the C/del haplotype was associated with an increased risk of GCA susceptibility (OR 2.10, 95% CI 1.23-3.60, p = 0.005), whereas the C/TG haplotype showed a protective effect (OR 0.63, 95% CI 0.45-0.87, p = 0.005). CONCLUSION: Our results suggest a potential role for the CD24 gene in the susceptibility to GCA in our population.