ascorbic-acid and Glaucoma--Open-Angle

The aim of is to determine the association of vitamins with glaucoma by performing a systematic review and meta-analyses.. Studies on the relation of vitamins and glaucoma published up to December 2017 were identified in the PubMed and Embase database. Data on vitamins (method of assessment), glaucoma (type and method of assessment), study characteristics and quality were recorded. In case of multiple studies for one nutrient a meta-analysis was performed.. A total of 629 articles were identified of which 36 were included in the systematic review. The meta-analysis included five of them (940 open-angle glaucoma (OAG) cases and 123,697 controls in total) and resulted in an odds ratio [95% confidence interval] (OR [95% CI]) of 0.58 [0.37-0.91] for dietary vitamin A, though heterogeneity was high (I² = 51%). After omitting studies that contributed significantly to the heterogeneity, the pooled OR [95% CI] was 0.45 [0.30-0.68] for dietary vitamin A on OAG (I² = 0%). For vitamin B1, C and E no significant association with OAG was found (OR [95% CI]: 0.84 [0.47-1.51]; 0.68 [0.38-1.22]; 0.95 [0.75-1.19]; respectively). However, after addressing heterogeneity, vitamin C showed a protective effect as well. Especially, foods high in these vitamins (e.g., dark green vegetables) were protective for OAG.. Dietary intake of vitamin A and C showed a beneficial association with OAG; however, findings on blood levels of vitamins do not show a clear relation with OAG.

Topics: Adult; Aged; Ascorbic Acid; Chi-Square Distribution; Diet; Glaucoma, Open-Angle; Humans; Middle Aged; Odds Ratio; Prevalence; Prognosis; Protective Factors; Risk Factors; Vitamin A

Primary open-angle glaucoma (POAG) is a complex chronic neurological disease that can result in blindness. The goal of understanding the aetiology of POAG is to be able to target effective treatment to individuals who will eventually go blind without it. Epidemiological studies of POAG have not specifically addressed the possibility that nutrition may play a role in the development of POAG. A handful of papers have considered that nutrition may have an impact on POAG patients. POAG is not believed to be a 'vitamin-deficiency disease'. The concept of 'vitamin-deficiency diseases' and the recommended daily allowances have not kept pace with the growing understanding of the cellular and molecular functions of vitamins and other micronutrients. The aetiology of POAG remains a mystery. Discoveries in cell physiology can be assimilated from the literature and applied to known homeostatic mechanisms of the eye. In this way the possible roles of nutritional components involved in the aetiology of POAG can be described. The mechanisms may be subject to many influences in ways that have yet to be defined. Two distinct changes in the trabecular meshwork can be identified: trabecular meshwork changes that cause intra-ocular pressure to increase and trabecular meshwork changes that are directly correlated to optic nerve atrophy. Compelling evidence suggests that collagen trabecular meshwork extracellular matrix (ECM) remodelling is correlated to increased intraocular pressure in POAG. Elastin trabecular meshwork ECM remodelling is correlated to POAG optic nerve atrophy. There appear to be two different pathways of ECM remodelling and apoptosis induction in POAG. The pathway for collagen remodelling and apoptosis induction seems to be exogenously influenced by water-soluble antioxidants, for example, glutathione. The pathway for elastin remodelling and apoptosis induction seems to be influenced by endogenous lipid-soluble antioxidants, for example, vitamin E. Roles can be defined for antioxidants in the two different pathways of ECM remodelling and apoptosis induction. This suggests that antioxidants are important in maintaining cellular homeostasis relevant to the aetiology of POAG.

Topics: Apoptosis; Ascorbic Acid; Axons; Collagen; Extracellular Matrix; Glaucoma, Open-Angle; Glutathione; Homeostasis; Humans; Intraocular Pressure; Nutritional Physiological Phenomena; Optic Nerve; Oxidative Stress; Trabecular Meshwork; Vitamin E

To study the association of selected polymorphism in genes related to vitamin E, vitamin C, and glutathione peroxidase with these biomarkers and primary open-angle glaucoma (POAG) risk.. A case-control study matched for age, sex, and bodyweight was undertaken. Two hundred fifty POAG cases and 250 controls were recruited from a Mediterranean population. Plasma concentrations of vitamin C, vitamin E, and glutathione peroxidase (GPx) activity were measured. We analyzed the polymorphisms rs1279683 in the Na(+)-dependent L-ascorbic acid transporter 2 (SLC23A2) gene, rs6994076 in the tocopherol alpha transfer protein (TTPA) gene, rs737723 in the tocopherol-associated protein (SEC14L2/TAP) gene, and rs757228 in the glutathione peroxidase 4 (GPX4) gene. We also analyzed expression of the SLC23A2 gene in a subsample.. We found a novel association between the rs737723 polymorphism and POAG risk. Homozygous subjects for the C allele had a higher POAG risk than carriers of the ancestral G allele (adjusted odds ratio 1.73, 95% confidence interval 1.13-2.65, p=0.011). This association remained statistically significant after adjustment for multiple comparisons. We also confirmed the association between the rs1279683 polymorphism and a higher POAG risk in GG homozygous subjects and detected statistically significant differences in SLC23A2 gene expression between POAG cases and controls, even after adjustment for multiple testing. We observed a nominally significant (p<0.05) gene-gene interaction between the SEC14L2/TAP and SLC23A2 polymorphisms in determining POAG risk, increasing POAG risk in those subjects who had both risk genotypes at the same time (p<0.01). This increase was statistically significant even after adjustment for multiple comparisons. We did not detect any association with POAG risk for the rs6994076 or rs757228 polymorphisms. We also found that POAG patients had statistically significant (after correction for multiple testing) lower plasma vitamin E (p<0.001) and vitamin C (p<0.001) concentrations than control subjects. However, we detected a higher plasma GPx activity in POAG cases than in controls (p<0.001). The rs6994076 and rs1279683 polymorphisms were significantly (p<0.001) associated with plasma vitamin E and vitamin C, respectively. However, the rs757228 polymorphism in the GPX4 gene was not associated with plasma GPx activity.. We have described a novel association between the rs737723 polymorphism (SEC14L2/TAP) and higher POAG risk and confirmed the association between rs1279683 (SLC23A2) and POAG. Our results also suggested a gene-gene interaction between both polymorphisms that increases POAG risk.

Topics: Aged; Ascorbic Acid; Biomarkers; Carrier Proteins; Case-Control Studies; Epistasis, Genetic; Female; Genetic Association Studies; Glaucoma, Open-Angle; Glutathione Peroxidase; Humans; Lipoproteins; Male; Middle Aged; Phospholipid Hydroperoxide Glutathione Peroxidase; Polymorphism, Genetic; Polymorphism, Single Nucleotide; Risk Factors; Sodium-Coupled Vitamin C Transporters; Trans-Activators; Vitamin E

To evaluate the role of antioxidant drugs in the tonometric increase that follows the closed eyelid test (CET), a predicitive test for glaucoma, after administration of antioxidant substances was observed.. 30 subjects of 54.57+/=5.62 years, 13 males and 17 females, were examined by measuring the ocular pressure after 1 hour from the CET, both in normal conditions and after the administration of antioxidants such as: vitamin A (50,000 IU/die), vitamin E (600 mg/die), and vitamin C (1000 mg/die). The increases in temperature of the iridocorneal angle and of the iris were also measured in the same conditions with an infrared Thermo-Precision tonometer (Sola Electro-Optics, China) both before and after CET.. The results showed increased pressure after CET and decreased pressure after the administration of each antioxidant substance, although vitamin A was found to be more effective and with statistically significant values compared to vitamins E and C.. Considering the responses obtained after administration of antioxidant drugs, the ocular hypertension induced after CET could be a response to mixed stress, oxidative and thermic, with degenerative effects on the trabecular meshwork (TM). Besides, in light of these considerations the research results underline that the open angle glaucoma (OAG) should be considered a multifactorial degenerative disease.

Topics: Antioxidants; Ascorbic Acid; Body Temperature; DNA Damage; Female; Glaucoma, Open-Angle; Humans; Male; Middle Aged; Oxidative Stress; Vitamin A; Vitamin E

Several dietary factors have been associated with glaucoma. Among them, dietary antioxidant intake (i.e., vitamin C and vitamin A) in association with glaucoma has been analyzed, but with mixed results. Genetic factors may play a role in modulating the effect of dietary antioxidant intake on glaucoma; however, nutrigenetic studies in this field are scarce. Our aim was to study the association between selected polymorphisms in key proteins related to vitamin C and vitamin A concentrations and primary open-angle glaucoma (POAG).. We performed a case-control study matched for age, sex, and bodyweight. We recruited 300 subjects (150 POAG cases and 150 controls) from a Mediterranean population and determined the plasma concentrations of vitamin C and vitamin A for each subject. We selected the following single-nucleotide polymorphisms (SNPs) in genes related to vitamin A and vitamin C concentrations: rs176990 and rs190910 in the retinol-binding protein 1 (RBP1) gene; and rs10063949 and rs1279683 in the Na⁺-dependent L-ascorbic acid transporters 1 and 2, respectively (encoded by the SLC23A1 and SLC23A2 genes).. We found a statistically significant association between the rs1279386 (A>G) SNP in SLC23A2 and POAG risk. In the crude analysis, homozygous subjects for the G allele (GG subjects) had higher risk of POAG than other genotypes (OR: 1.67; 95% CI: 1.03-2.71). This association remained statistically significant (p=0.010) after multivariate adjustment for potential confounders. We also found that POAG patients had lower plasma vitamin C concentrations than control subjects (9.9±1.7 µg/ml versus 11.7±1.8 µg/ml, p<0.001). Moreover, we consistently detected a significant association between the rs1279386 SNP in SLC23A2 and plasma vitamin C concentrations: GG subjects had significantly lower plasma vitamin C concentrations than the other genotypes (9.0±1.4 µg/ml versus 10.5±1.6 µg/ml, p<0.001 in POAG cases and 10.9±1.6 µg/ml versus 12.1±1.8 µg/ml, p<0.001 in controls). The rs10063949 SNP in SLC23A1 was not associated with either plasma vitamin C concentrations or POAG risk. Similarly, SNPs in RBP1 were not associated with vitamin A concentrations or POAG risk.. The rs1279683 SNP in SLC23A2 was significantly associated with lower plasma concentrations of vitamin C and with higher risk of POAG in GG subjects.

Topics: Aged; Ascorbic Acid; Case-Control Studies; Female; Gene Frequency; Genetic Predisposition to Disease; Genetics, Population; Glaucoma, Open-Angle; Humans; Male; Mediterranean Region; Polymorphism, Single Nucleotide; Risk Factors; Sodium-Coupled Vitamin C Transporters; Vitamin A

Vitamin A, B(9), C, E, and uric acid are well-known antioxidants and may prevent age-related eye disorders. The aim of the present study was to investigate the levels of antioxidant vitamins, A, B(9), C, E, and antioxidative substance, uric acid in the serum of Japanese patients with normal-tension glaucoma and compare the results with normal controls.. All subjects with suspicion of primary open-angle glaucoma who came to the glaucoma subspeciality clinic of Keio University Hospital were enrolled in this study. Sixty patients (28 males, 32 females; mean age +/- standard deviation: 59.9 +/- 9.8 years) with newly diagnosed primary open-angle glaucoma patients were consecutively enrolled in this study. After the diagnosis of primary open-angle glaucoma, the patients underwent 24-h IOP measurements. Forty-seven newly diagnosed consecutive normal-tension glaucoma patients (18 males, 29 females; mean age +/- standard deviation: 59.5 +/- 10.2 years) were enrolled in this study. The control subjects were recruited from subjects who came to the clinic for annual refractive check-up. The 44 consecutive control subjects of the current study, (16 males, 28 females; 62.7 +/- 14.8 years) did not have any ocular diseases. The serum levels of vitamins A, B(9), C, E, and uric acid were measured. The values were compared between the normal-tension glaucoma and control groups by the Mann-Whitney U test.. Serum levels of vitamin C were significantly lower in normal-tension glaucoma patients than in normal healthy controls (P = 0.04; normal-tension glaucoma; 4.6 +/- 4.0 microg/ml control; 6.3 +/- 3.9 microg/ml). Uric acid level was significantly higher in normal-tension glaucoma patients than in controls (P = 0.01; normal-tension glaucoma; 5.8 +/- 1.5 mg/dl control; 4.9 +/- 1.4 mg/dl). No statistically significant difference was seen in vitamin A (P = 0.41; normal-tension glaucoma; 82.1 +/- 26.7 microg/dl control; 77.1 +/- 30.1 microg/dl), B(9) (P = 0.37; normal-tension glaucoma; 8.7 +/- 4.3 ng/ml control; 8.0 +/- 3.1 ng/ml)and E (P = 0.83; normal-tension glaucoma; 1.5 +/- 0.6 control; 1.5 +/- 0.6) levels between normal-tension glaucoma and control groups.. Normal-tension glaucoma patients had lower serum levels of vitamin C and increased levels of uric acid. These observations may pave the way for possible alternative treatment for normal-tension glaucoma.

Topics: Aged; Ascorbic Acid; Ascorbic Acid Deficiency; Asian People; Female; Glaucoma, Open-Angle; Humans; Low Tension Glaucoma; Male; Middle Aged; Oxidative Stress; Uric Acid; Vitamin B Complex; Vitamin E

To establish the antioxidant status of the aqueous humour in glaucoma associated with exfoliation syndrome (XFG) and to compare it to primary open-angle glaucoma (POAG) and cataract patients.. Patients were diagnosed with POAG, XFG, or cataract (n=25 for each group). Total reactive antioxidant potential (TRAP) was measured by chemiluminescence. Ascorbic acid levels and the activities of catalase, glutathione peroxidase (GPx), and superoxide dismutase (SOD) were measured spectrophotometrically.ResultsTRAP value was lower in XFG (28+/-2 microM Trolox) than in POAG (55+/-8 microM Trolox; P<0.001). TRAP values in both glaucomas were lower than the cataract value (124+/-5 microM Trolox; P<0.001). A decrease in ascorbic acid was measured in XFG (230+/-20 microM) compared with POAG (415+/-17 microM; P<0.001). Ascorbic acid in both glaucomas was lower than in cataract (720+/-30 microM; P<0.001). A significant increase in GPx was found in XFG (30+/-2 U/ml) compared with POAG (16+/-3 U/ml). GPx activity in both glaucomas was increased when compared with cataracts (6+/-2 U/ml; P<0.001). A significant increase of 67% in SOD activity was observed in the glaucoma group vscataract group (27+/-3 U/ml; P<0.001), but no changes were found between both glaucomas.. The antioxidant status of the aqueous humour may play a role in the pathophysiology of both glaucomas.

Topics: Aged; Aged, 80 and over; Antioxidants; Aqueous Humor; Ascorbic Acid; Catalase; Cataract; Exfoliation Syndrome; Female; Glaucoma; Glaucoma, Open-Angle; Glutathione Peroxidase; Humans; Luminescence; Male; Superoxide Dismutase

We aimed to evaluate the ascorbic acid concentration in secondary aqueous humour (AH) from glaucomatous patients and to compare it with primary AH from primary open-angle glaucoma patients and non-glaucomatous patients.. Primary AH samples were prospectively obtained from clinically uncontrolled primary open-angle glaucoma patients and senile cataract patients (controls) prior to trabeculectomy and cataract surgery. Secondary AH samples were obtained from eyes with previous intraocular surgery, prior to trabeculectomy or cataract surgery. AH (0.1 mL) was aspirated by inserting a 26-gauge needle into the anterior chamber just before surgery and then immediately stored at -80 degrees C. The ascorbic acid concentration was determined in a masked fashion by high-pressure liquid chromatography.. A total of 18 patients with senile cataract, 16 glaucomatous patients with primary AH (no previous intraocular surgery) and 11 glaucomatous patients with secondary AH (previous intraocular surgery) were included. There was no difference in mean age between groups (P = 0.15). The mean +/- standard deviation concentration of ascorbic acid in the secondary AH from glaucomatous patients (504 +/- 213 micromol/L [95% confidence interval {CI}, 383-624]) was significantly lower than the concentration of ascorbic acid found in the primary aqueous of primary open-angle glaucoma (919 +/- 427 micromol/L [95% CI, 709-1128]) and control patients (1049 +/- 433 micromol/L [95% CI, 848-1249]; P < 0.01, Kruskal-Wallis test).. The ascorbic acid concentration in secondary AH of glaucomatous patients was approximately twofold lower in comparison with primary AH of glaucomatous and cataract patients. The implications of a reduced concentration of ascorbic acid in the secondary AH deserve further investigation.

Topics: Aged; Aqueous Humor; Ascorbic Acid; Cataract Extraction; Chromatography, High Pressure Liquid; Female; Glaucoma, Open-Angle; Humans; Intraocular Pressure; Male; Prospective Studies; Trabeculectomy

The relation between dietary antioxidant intake and primary open-angle glaucoma risk was examined in participants aged over 40 years in the Nurses' Health Study (n = 76,200) and the Health Professionals Follow-up Study (n = 40,284). They were followed biennially from 1980 and 1986, respectively, to 1996, during periods when they received an eye examination. Dietary intakes were measured repeatedly from 1980 in the Nurses' Health Study and from 1986 in the Health Professionals Follow-up Study using validated food frequency questionnaires. The authors analyzed 474 self-reported glaucoma cases confirmed by medical chart review to have primary open-angle glaucoma with visual field loss. The authors used Cox proportional hazards models for cohort-specific multivariate analyses, and results were pooled using random effects models. The pooled multivariate rate ratios for primary open-angle glaucoma comparing the highest versus lowest quintile of cumulative updated intake were 1.17 (95% confidence interval (CI): 0.87, 1.58) for alpha-carotene, 1.10 (95% CI: 0.82, 1.48) for beta-carotene, 0.95 (95% CI: 0.70, 1.29) for beta-cryptoxanthin, 0.82 (95% CI: 0.60, 1.12) for lycopene, 0.92 (95% CI: 0.69, 1.24) for lutein/zeaxanthin, 1.05 (95% CI: 0.59, 1.89) for vitamin C, 0.97 (95% CI: 0.62, 1.52) for vitamin E, and 1.11 (95% CI: 0.82, 1.51) for vitamin A. In conclusion, the authors did not observe any strong associations between antioxidant consumption and the risk of primary open-angle glaucoma.

Topics: Adult; Aged; Antioxidants; Ascorbic Acid; beta Carotene; Carotenoids; Cryptoxanthins; Diet; Dietary Supplements; Female; Glaucoma, Open-Angle; Humans; Lutein; Lycopene; Male; Middle Aged; Multivariate Analysis; Proportional Hazards Models; Prospective Studies; Surveys and Questionnaires; Vitamin A; Vitamin E; Xanthophylls; Zeaxanthins

Investigations of aqueous humor in primary open-angle glaucoma have shown a change in its normal contents: decreased ascorbic acid in it and increased secondary products of lipid peroxidation. In patients with glaucoma of stages III and IV, a correlative relationship between them is recorded (r = -0.78). It is suggested that in the pathomechanism of increased intraocular pressure in primary glaucoma activation of the process of lipid peroxidation plays a role due to decreased concentration of ascorbic acid in the aqueous humor, being one of the most important components of antioxidative system of the eye.

Topics: Aged; Aqueous Humor; Ascorbic Acid; Cataract; Female; Glaucoma, Open-Angle; Humans; Lipid Peroxidation; Male; Middle Aged; Spectrophotometry; Thiobarbiturates