Methylenetetrahydrofolate reductase 677 C-T and homocysteine levels in Turkish patients with pseudoexfoliation

PURPOSE: The 677 C-T polymorphism in the methylenetetrahydrofolate reductase (MTHFR) gene is associated with hyperhomocysteinaemia. This study aimed to investigate the frequency of MTHFR 677 C-T polymorphism and homocysteine (Hcy) levels in Turkish patients with pseudoexfoliation (PEX). METHODS: This prospective study consisted of 60 patients with PEX glaucoma, 16 with PEX syndrome and 34 controls. All patients and control subjects were of Turkish origin. All participants underwent a complete ophthalmic examination. Plasma Hcy levels were measured using fluorescence polarization immunoassay (Abbott Diagnostics). Hyperhomocysteinaemia was defined as a plasma Hcy level above 14 micromol/L. MTHFR 677 C-T was genotyped by real-time polymerase chain reaction (Roche Diagnostics). RESULTS: There was no statistically significant difference in patient and control groups for the age and sex (P > 0.05). The mean plasma Hcy levels were 15.76, 14.98 and 17.43 micromol/L in patients with PEX glaucoma, with PEX syndrome and controls, respectively. No significant differences between Hcy levels among the three groups (P > 0.05) were found. MTHFR 677 polymorphism did not show significant differences between the total patients with PEX (PEX glaucoma + PEX syndrome) and control subjects (CC: 51.3%n = 39, CT: 40.8%n = 31, TT: 7.9%n = 6 for patients with PEX; CC: 52.9%n = 18, CT: 35.3:%n = 12, TT: 11.8%n = 4 for controls) (P > 0.05). Frequency of T allele was 28.28% and 29.41% for the total patients with PEX and controls, respectively. CONCLUSION: In Turkish patients with PEX, the authors could not find any association between Hcy levels, MTHFR 677 C-T polymorphism, and the disease.     

原发性闭角型青光眼血浆同型半胱氨酸水平及其代谢相关指标的检测分析

目的：：探讨同型半胱氨酸水平及其代谢相关指标与原发性闭角型青光眼的关系。方法：选取150例经压平眼压计、Humphrey 视野计( HVF)、光学相干断层扫描( optical coherence tomography, OCT)、房角镜等检查确诊为原发性闭角型青光眼( primary angle-closure glaucoma,PACG)的患者作为试验组和同期150例我院体检中心健康者为正常对照组,抽取空腹外周静脉血,而后测定血浆中同型半胱氨酸( homocysteine, Hcy)浓度、维生素B12及叶酸的浓度,并提取DNA,检测Hcy代谢途径中关键酶———亚甲基四氢叶酸还原酶(methylenetetrahydrofolate reductase,MTHFR) C677T 的基因型及基因多态性。结果：试验组血浆中Hcy的浓度为16.11±1.66μmol/L,正常对照组为15.74±1.52μmol/L,两组比较,差异有统计学意义(t=2.04,P=0.04)。试验组血浆中维生素B12的浓度为248.09±119.07pg/mL,正常对照组为230.21±142.93pg/mL,两组比较差异无统计学意义( t=0.84,P=0.40)。试验组血浆中叶酸的浓度为12.02±7.81ng/mL,正常对照组为13.15±6.25ng/mL,两组比较差异无统计学意义( t=1.65, P=0.17)。试验组MTHFR C677 T基因型(CC、CT、TT)分布频率分别84.7%、4.7%、10.7%,正常对照组分别为94.7%、2.0%、3.3%,两组基因型分布频率差异具有统计学意义(χ2=6.2,P<0.05);其中试验组MTHFR基因TT纯合子的分布频率高于正常对照组;试验组 MTHFR 基因 T、C 等位基因频率分别为87.0%、13.0%,正常对照组为95.7%、4.3%,两组差异具有统计学意义(χ2=14.2,P<0.05)。结论：PACG患者血浆中Hcy的浓度及MTHFR基因型TT纯合子的分布频率高于正常对照组,说明高Hcy水平及其代谢相关因素可能与PACG的发病与发展密切相关。     

Increased corneal thickness in active Behçet's disease

PURPOSE: To measure central corneal thickness (CCT) in patients with Beh?et's disease (BD), particularly in the active disease. MATERIALS AND METHODS: We measured CCT by ultrasound pachymetry in 64 patients with Beh?et's disease and in 20 healthy controls. Forty-one of the patients with BD had ocular involvement and 23 none; 19 of the 41 with ocular involvement were in an active period and 22 had inactive disease. RESULTS. The mean CCT in the group with active ocular involvement was significantly higher (589+/-27 microm) than in the control group (553+/-21 microm) (p = 0.003), the group with inactive ocular involvement (560+/-26 microm) (p < 0.001), and the group with no ocular involvement (558+/-25 microm) (p < 0.001). After appropriate treatment of patients with active ocular involvement, the mean CCT returned nearly to normal (563+/-20 microm) and the difference from controls was not significant. There was no significant difference for the mean CCT between controls and the patients with no ocular involvement or with inactive ocular involvement. CONCLUSIONS. Beh?et's patients with active ocular involvement have a thicker CCT than patients with inactive ocular involvement. There was no difference in CCT between controls and patients with no ocular involvement. The CCT of patients with active ocular involvement returned to nearly normal after treatment. CCT must be taken into account when developing a managing and following approach for Behcet's patients with active ocular involvement.     

Evaluation of serum resistin levels in patients with ocular and non-ocular Behçet's disease

Background: Resistin, a recently identified adipocytokine, has been found to play an important role in inflammation and the processes of inflammation-related diseases. Serum resistin levels in patients with Beh?et's disease (BD) have not yet been investigated. We aimed to evaluate the relation between resistin and interleukin-6 (IL-6) in Beh?et patients with or without ocular involvement and in normal controls. Methods: Twenty-two patients with BD and 19 healthy control subjects were included in this study. While 14 patients had posterior segment involvement of the eye, the other 8 did not have ocular disease. Serum resistin and interleukin-6 (IL-6), levels were measured in all samples. Data from all groups were tested for statistical significance. Results: The mean resistin and IL-6 concentrations were significantly higher in patients with BD than the control subjects (p = 0.011 and p = 0.0001, respectively). There was a significant difference in resistin and IL-6 levels between the patients with non-ocular BD and controls (p = 0.013 and p = 0.0001, respectively), as well as resistin and IL-6 levels between the ocular BD group and the control group (p = 0.05 and p = 0.0001, respectively). However, there was no significant difference between patients with ocular versus non-ocular BD. Interpretation: Resistin levels were found to be raised in Beh?et patients with or without ocular involvement compared with the control subjects.     

Comparison of serum nitric oxide, malondialdehyde levels, and antioxidant enzyme activities in Behçet's disease with and without ocular disease

OBJECTIVE: The pathogenesis of Beh?et's disease (BD) may be related to excessive production of reactive oxygen species, activated neutrophils, and T lymphocytes. The goal of this prospective study was to investigate whether there is any relationship among the oxidant/antioxidant system and nitric oxide (NO) and malondialdehyde (MDA) levels in patients with BD and its subtypes: complete Beh?et's disease (CBD) and incomplete Beh?et's disease (ICBD), with or without ocular disease. METHODS: Thirty-two patients and 26 age- and sex-matched healthy control subjects were evaluated for NO and MDA levels and antioxidant enzyme activities. The patients with BD were divided into two subgroups: those with and without ocular disease. Twelve patients with CBD and 4 patients with ICBD had ocular disease. The serum NO level was determined by Griess reaction. The MDA level was detected by thiobarbituric acid reaction. Superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activities in serum were analyzed with spectrophotometric methods. RESULTS: Increased MDA levels but decreased GSH-Px activities in plasma were observed in BD patients with all subtypes, as compared with controls. Concerning the presence of ocular disease and the subtype (CBD or ICBD) compared with each other, there were no significant differences in MDA or NO serum levels and SOD or GSH-Px enzyme activities. CONCLUSIONS: Serum NO levels and SOD enzyme activities were not significantly changed in patients with BD and its subtypes; however, a remarkable decrease of GSH-Px enzyme activity and increase of MDA levels were found.     

Behçet's disease: ocular effects and treatment

Beh?et's disease (BD) is a systemic immune-mediated vasculitis of unclear origin. Major symptoms include oral aphthous ulcers, genital ulcerations, skin lesions, and ocular lesions. Eye involvement, which affects 60-80% of BD patients, is characterized by posterior or panuveitis with occlusive retinal vasculitis. The pathogenesis of BD remains unclear, but research of the last decades has shown a complex role of genetic factors (HLA-B51) predisposing to inflammation with involvement of the innate-immune system (neutrophils, NK cells), perpetuated by the adaptive immune response, most importantly T cells, against infectious- and/or auto-antigens. Despite aggressive immunosuppressive treatment, the visual prognosis of ocular BD was generally poor to date. Recently, novel biologic drugs, including interferon-alpha and tumour necrosis factor (TNF)-alpha-antagonists have been introduced in the treatment of ocular BD with very promising results and seem for the first time to improve the prognosis of the disease. This article will provide a current review of BD including recent developments in epidemiology, immunology, genetics, and treatment.     

C677T variant in the methylentetrahydrofolate reductase gene is a genetic risk factor for primary open-angle glaucoma

PURPOSE: To estimate the prevalence of C677T single nucleotide polymorphism in the 5,10-methylentetrahydrofolate reductase (MTHFR) gene in primary open-angle glaucoma (POAG) and pseudoexfoliation open-angle glaucoma (PEXG). DESIGN: Case-control study METHODS: MTHFR was assessed in 147 patients (76 POAG, 71 PEXG) and 71 control subjects with cataract. Associations of genotypes were assessed by Armitage's trend test and the corresponding odds ratio (OR) for allele positivity with 95% confidence interval (CI). RESULTS: We observed significant evidence of a higher prevalence of C677T in POAG (9% homozygote, 49% heterozygote, 42% wildtype, P = .01, OR = 2.38, 95% CI 1.23-4.62), but not in PEXG (9% homozygote, 41% heterozygote, 50% wildtype, P = .09, OR = 1.78, 95% CI 0.91-3.50) compared with the controls (3% homozygote, 34% heterozygote, 63% wildtype). CONCLUSIONS: The MTHFR C677T variant leading to moderate hyperhomocysteinemia may play a role in the pathogenesis of POAG acting as a genetic risk factor.     

甲基四氢叶酸还原酶基因多态性与 糖尿病视网膜病变的关系

目的探讨中国汉族人甲基四氢叶酸还原酶(ethylenetetrahydrofolate reductase,MTHFR)因多态性与糖尿病视网膜病变(iabetic retinopathy, DR)生和发展的关系。方法利用聚合酶链反应限制性片段长度多态性分析法(olymerase chain reaction and restriction fragme nt length polymorphism, PCR-LP)测85名中国汉族健康人、经检眼镜检查确诊的62 例合并DR和117例无DR 的中国汉族人2型糖尿病患者MTHFR基因第677位碱基多态性(C677T)。 结果DR患者MTHFR基因变异型纯合子和等位基因频率均明显高无DR的糖尿病患者及健康人(P<0．01)。结论MTHFR基因第677位碱基变异可能是中国汉族人DR发生的一个遗传危险因子。(中华眼底病杂志,2001,17:198-200)     

Retinal vein occlusion, homocysteine, and methylene tetrahydrofolate reductase genotype

PURPOSE: The aim of this case-control study was to investigate the relationship between homocysteine (tHcy), 5,10 methylene tetrahydrofolate reductase (MTHFR) C677T genotype, folate and vitamin B12 status, and retinal vein occlusion (RVO). METHODS: Subjects with RVO (n = 106) were recruited from outpatient and inpatient sources. Controls (n = 98) were selected to achieve a similar age and sex distribution. Full ocular examination was performed and medical history was taken for each study participant. Plasma and serum samples were analyzed for tHcy level and folate and vitamin B12 status, and extracted DNA was assessed for the MTHFR C677T genotype. RESULTS: There was no significant difference in plasma tHcy level or thermolabile MTHFR allele frequency between subjects and controls. Similarly, there was no significant difference in folate or vitamin B12 status between subjects and controls. MTHFR genotype did not affect folate or vitamin B12 concentrations in subjects or controls. However, tHcy was significantly higher in thermolabile homozygotes than in nonthermolabile homozygotes (ratio of geometric means, 1.35; 95% confidence interval [CI], 1.04-1.74; P = 0.024). CONCLUSIONS: Hyperhomocysteinemia, the MTHFR C677T mutation, and folate and vitamin B12 status are not important risk factors for RVO in this population.     

Methylenetetrahydrofolate reductase genetic polymorphisms in patients with primary open-angle glaucoma

PURPOSE: Hyperhomocysteinemia has been found in patients with primary open-angle glaucoma. The purpose of the present study was to determine if hyperhomocysteinemia-associated polymorphisms of the methylenetetrahydrofolate reductase gene (MTHFR) are overrepresented in primary open-angle glaucoma. METHODS: Patients with primary open-angle glaucoma (n = 243) and controls (n = 187) were analyzed for the MTHFR 677 C > T and 1298 A > C polymorphisms using minisequencing technique. RESULTS: No significant differences were observed in allele and genotype frequencies of the MTHFR 677C > T and 1298A > C polymorphisms between controls and the primary open-angle glaucoma group. CONCLUSIONS: If hyperhomocysteinemia is important in the pathogenesis of glaucoma, this study does not support a role for MTHFR polymorphisms in this context.     

RFLP analysis in the TNF-beta gene and the susceptibility to alloreactive NK cells in Beh?et's disease.

Beh?et's disease is known to be associated with HLA-B51. To address the possibility that a non-human leukocyte antigen (HLA) gene closely linked to the HLA-B gene, such as tumor necrosis factor (TNF)-alpha, TNF-beta, or ECl (the locus that determines the susceptibility to alloreactive natural killer [NK] cells), is involved in the susceptibility to Beh?et's disease, NcoI and EcoRI restriction fragment length polymorphisms in the TNF-beta gene and the susceptibility to lysis by alloreactive NK cells were investigated in Beh?et's patients. In our NcoI restriction fragment length polymorphism (RFLP) analysis in the TNF-beta gene, the frequency of the NcoI 5.5 kb homozygote was decreased considerably in the patients, especially those with the ocular lesions, in relation to the healthy controls. However, no significant difference was observed between these groups in the EcoRI RFLP band distribution in this gene or the in susceptibility to lysis by alloreactive NK cells. These results indicated that a non-HLA gene located around the TNF gene region centromic of the HLA-B gene was a candidate to control the genetic susceptibility to Beh?et's disease.     

A study of familial occurrence of Behçet's disease with and without ocular lesions

PURPOSE: To examine retrospectively the features of Beh?et's disease patients with familial occurrence and make a comparison between familial Beh?et's patients with ocular lesions and those without ocular lesions. METHODS: We sent questionnaires about Beh?et's disease patients with familial occurrence to 114 hospitals that reported treating such patients in previous nationwide hospital surveys, and to 341 hospitals selected at random in Japan. RESULTS: We obtained reports on 83 Beh?et's patients with familial occurrence. The positive rate of HLA-B51 was 53.1%. The positive rate of HLA-B51 among patients with ocular lesions was 64.0%, that in patients without ocular lesions was 14.3%, and that in patients with genital ulcers was 40.9%. The mean birth year and onset year of the patients with ocular symptoms was significantly lower than that of the patients without ocular symptoms. Although there was no significant difference between these two groups, parent-child involvement was more common among the patients without ocular lesions than in those with ocular lesions. CONCLUSIONS: The findings of this study suggest that the number of familial Beh?et's disease patients with ocular lesions and high HLA-B51 positivity has been decreasing recently. To elucidate the etiology of familial occurrence, larger scale epidemiological studies and further molecular studies of Beh?et's disease are needed.     

The demonstration of serum interleukin 6-8, tumor necrosis factor-alpha, complement, and immunoglobulin levels in Behçet's disease with ocular involvement

PURPOSE: To investigate whether there are alterations in the humoral immune system in patients with Beh?et's disease (BD) with ocular involvement. METHODS: Twenty-four BD patients with active uveitis and without any other manifestations of the disease were included in Group I-a. The same patients were reassessed during the convalescence period and assigned to Group I-c. Moreover, 24 age- and sex-matched healthy controls (Group II) were included in the study. Serum levels of immunoglobulin (Ig) A, IgM, complement (C) 3, C4, interleukin (IL)-6, IL-8, and tumor necrosis factor-alpha (TNF-alpha) in Groups I-a, I-c, and II were measured and compared. RESULTS: IgA, C3, C4, IL-6, IL-8, and TNF-alpha levels were higher in Group I-a than in Groups I-c and II. CONCLUSIONS: IgA-, C3-, C4-, IL6-, IL8-, and TNF-alpha-mediated mechanisms might be responsible for ocular lesions in BD.     

Endothelial cell activation and hypercoagulability in ocular Behçet's disease

PURPOSE: To investigate the presence of a hypercoagulable state and vascular endothelial dysfunction in patients with ocular Beh?et's disease and relate the results to the activity of ocular and systemic involvement. DESIGN: Cross-sectional laboratory and clinical study. METHODS: Prospective study of blood samples of 24 patients diagnosed with ocular Beh?et's disease, which were analyzed for factor VIII, factor XI, von Willebrand factor antigen and ristocetin (vWF ag and risto), antithrombin III (ATIII), protein C and S, fibrinogen and activated protein C (APC) resistance. The results were compared with 40 healthy controls and analyzed for association with ocular and systemic clinical features. RESULTS: The mean values of factor VIII, factor XI, vWF ag, vWF risto, ATIII, and fibrinogen were significantly raised compared to healthy population (for all: P <.001). Most striking were factor VIII activity levels above 130% in 79% (19 of 24) of our patients. 67% (16 of 24) had levels of factor VIII above 150%, which correlates with a fivefold increase in risk of thrombosis. Other prothrombogenic factors were negative in all but 2 patients (1 protein C deficiency, 1 factor V Leiden mutation). Endothelial cell activation, measured by vWF activity, revealed elevated levels in 42% (10/24). Complete/incomplete Beh?et's disease patients with present or previous macular edema had significantly higher FVIII levels than complete/incomplete Beh?et's disease patients who had never shown any signs of macular edema (P =.04). Further correlations between the laboratory results and clinical symptoms were not found. CONCLUSIONS: We found a generalized hypercoagulable state with endothelial cell activation in ocular Beh?et's disease, irrespectively of current ocular disease activity.     

The association between HLA B5 and ocular involvement in Beh?et's disease in southern Turkey.

HLA B5 plays an important role in the aetiology of Beh?et's disease. The frequency of HLA B5 differs between racial groups and geographical regions. Ocular involvement, which could lead to serious complications, is a very important feature of Beh?et's disease. Various racial groups having different genetic properties live in the Cukurova region, located in southern Turkey. To investigate the role of HLA B5 in Beh?et's disease in Cukurova region, HLA B5 antigens were investigated by lymphocytotoxicity assay in 65 patients and 200 healthy controls. A significantly higher frequency was found in the patient group. Neither ocular involvement, nor the type of uveitis showed any correlation with HLA B5, but it was found that patients presenting with frequent ocular attacks had significantly higher HLA B5 positivity than the patients with rare attacks. This observation suggests that HLA B5 would be a negative factor in visual prognosis in Beh?et's disease.     

Hyperhomocyst(e)inemia,but not methylenetetrahydrofolate reductase C677T mutation,as a risk factor in branch retinal vein occlusion

OBJECTIVE: To determine whether hyperhomocyst(e)inemia and methylenetetrahydrofolate reductase (MTHFR) C677T mutation are associated with branch retinal vein occlusion (BRVO). DESIGN: Retrospective, case-control study. PARTICIPANTS: The study cohort consisted of 84 consecutive patients with branch retinal vein occlusion and 84 controls, matched for age and gender. MAIN OUTCOME MEASURES: Fasting plasma homocyst(e)ine, folate, and vitamin B(12) levels, MTHFR C677T genotypes. RESULTS: Mean plasma homocyst(e)ine levels were significantly higher in patients than in controls (11.4 +/- 4.3 micromol/l vs. 9.9 +/- 2.8 micromol/l; P = 0.002). An increase of plasma homocyst(e)ine level by 1 micromol/l was associated with an odds ratio of 1.19 (95% confidence interval 1.06-1.34; P = 0.004). Mean plasma folate levels were significantly lower in patients than in the control group (4.5 +/- 2.1 ng/ml vs. 5.6 +/- 2.1 ng/ml; P = 0.007). The prevalence of the homozygous genotype of the MTHFR C677T mutation did not differ significantly between patients and controls. CONCLUSIONS: Our results suggest that hyperhomocyst(e)inemia, but not homozygosity for the MTHFR C677T mutation, is associated with BRVO. Increased plasma homocyst(e)ine levels in our study are not the result of an increased prevalence of the homozygous genotype of MTHFR C677T mutation.     

Central retinal artery occlusion associated with ocular Behçet's disease

PURPOSE: To report a case of central retinal artery occlusion associated with ocular Beh?et's disease (BD) and briefly discuss retinal vasculitis due to BD. CASE REPORT: A 52-year-old man, diagnosed as BD 22 years ago and followed up with ocular involvement for six years presented with sudden loss of vision. The clinical diagnosis was central retinal artery occlusion. RESULTS: No other associated systemic diseases were found and the case was classified as a complication of retinal vasculitis due to BD. CONCLUSIONS: Although the arteries are rarely affected in retinal vasculitis due to BD, it has to be considered in the differential diagnosis of retinal arterial occlusions especially in countries where the disease is prevalent. To our knowledge, this is the first reported case of ocular BD complicated with central retinal artery occlusion.     

Immunogenetic and molecular genetic studies on ocular diseases]

The immunogenetic mechanisms of various ocular diseases were investigated utilizing recently developed molecular biological and molecular genetic techniques. It was revealed that HLA-B 51 was closely associated with Beh?et's disease. Investigation of genetic polymorphism of TNF-beta (tumor necrosis factor-beta) showed that 95% of Beh?et's disease patients had the 10.5 kbp Nco I fragment. It was therefore concluded that the gene of susceptibility to Beh?et's disease is located between HLA-B and TNF-beta loci on the short arm of chromosome 6. Similar studies of HLA-DNA typing in Harada's disease frequently seen in Japan showed that frequencies of HLA-DRB1 * 0405, HLA-DQA1 * 0301 and HLA-DQB1 * 0401 were significantly increased in patients compared with normal controls. These data suggested that those who have serine at position 57 of HLA-DR, glutamic acid at position 70 and aspertic acid at position 71 of HLA-DQ respond to certain unknown agents significantly more than those without them, thus leading to the development of Harada's disease. The same HLA association was observed between Harada's disease and sympathetic ophthalmia, and the immunogenetic mechanism was thought to be similar in both diseases. Recent immunogenetic and molecular genetic investigations on various ocular diseases have shed new light not only on the genetic individual susceptibility and biased racial differences, but also on the diagnosis of the ocular diseases, reclassification of disease entities according to HLA associations, and judgement of disease prognosis. Further progress of molecular medicine may make it possible to treat various intractable ocular diseases by gene therapy in the near future.     

Heidelberg retina tomograph in ocular Behçet's disease

PURPOSE: To compare the optic disc topography of patients with ocular Beh?et's disease (BD) with age-matched controls, using Heidelberg retina tomograph (HRT). METHODS: This study included 32 patients (51 eyes) with ocular BD (active and/or inactive), 38 patients (74 eyes) with nonocular BD, and 62 normal subjects (62 eyes). All patients and control group underwent complete ophthalmologic evaluation. Intraocular pressure was less than 22 mmHg in patients and in the control group. The optic nerve heads of all subjects were imaged with the HRT (software 2.01a-M). The following stereometric parameters were calculated for each patient: disc area, cup area, cup/disc area ratio, rim area, height variation contour, cup volume, rim volume, mean cup depth, cup shape measure, mean RNFL thickness, and RNFL cross-sectional area. Differences among the groups were evaluated by Kruskal-Wallis variance analysis. When the Kruskal-Wallis test revealed a significant difference between groups, multiple comparison tests were used to find out which groups differed from which others. RESULTS: The mean disc area was significantly smaller (P<0.05) in patients with ocular and nonocular BD. The mean cup area, mean cup depth, and mean cup volume were significantly smaller (P<0.05) in patients with ocular BD. No significant differences were found between the groups in terms of the other stereometric parameters (P>0.05). CONCLUSION: A small disc and cup may be an additional risk factor for retinal vaso-occlusion in ocular Beh?et's disease.