SERUM VITAMIN D LEVELS IN DIFFERENT MORPHOLOGIC FORMS OF AGE RELATED CATARACT

Purpose

Vitamin D insufficiency and age related cataract (ARC) are public health problems. We evaluated serum vitamin D levels in ARC patients.

Method

A prospective hospital-based cross-sectional study was designed to measure the vitamin D status of patients with ARC. Patients have grouped either presence of any type of posterior subcapsular cataract (PSC) (group 1) or ARC without the PSC component (Group 2). After full ophthalmologic consideration, patients over 40 years of age with no history of ocular trauma, multivitamin supplement ingestion, chronic renal failure, thyroidectomy, parathyroidectomy, skin cancer, and cigarette smoking were included in the study.

Results

Totally, 79 subjects of which 26 (32.9%) subjects in group 1 and 53 (67.1%) subjects in group 2 were included in the study. Group 1 had mean vitamin D levels of 17.31±13.30 ng/mL. Vitamin D levels in Group 2 were 13.34±7.87 ng/mL. Group 1 did not show vitamin D insufficiency (P = 0.31; one-sample t-test). However, Group 2 showed a statistically significantly lower vitamin D level compared to the insufficiency level of 20ng/mL (P= 0.00; one-sample t-test).

Conclusion

Vitamin D may have an important function in lens metabolism. Vitamin D deficiency and cataract development need further extensive researches.

WRN inhibits oxidative stress-induced apoptosis of human lensepithelial cells through ATM/p53 signaling pathway and its expression is downregulated by DNA methylation

BACKGROUND

Apoptosis and oxidative stress are the main etiology of age related cataract (ARC). This article aims to investigate the role of WRN in lens epithelial cells (LECs).

METHODS

We estimated the methylation level of WRN in anterior lens capsule tissues of ARC patients. SRA01/04 (LECs) cells were treated with H2O2 or combined with 5-aza-2-deoxycytidine (5-Aza-CdR) or chloroquine. CCK8 and flow cytometry were performed to explore proliferation and apoptosis. The content of ROS was detected by fluorescent probe DCFH-DA. The gene and protein expression was assessed by quantitative real-time PCR or western blot.

RESULTS

WRN was down-regulated and the methylation level of WRN was increased in the anterior lens capsule tissues. WRN overexpression and 5-Aza-CdR enhanced proliferation and repressed apoptosis and oxidative stress of SRA01/04 cells. 5-Aza-CdR enhanced WRN expression. WRN knockdown inhibited proliferation and promoted apoptosis and oxidative stress of SRA01/04 cells, which was rescued by 5-Aza-CdR. WRN overexpression and 5-Aza-CdR repressed ATM/p53 signaling pathway. Furthermore, chloroquine inhibited proliferation and promoted apoptosis and oxidative stress of SRA01/04 cells by activating ATM/p53 signaling pathway. The influence conferred by chloroquine was abolished by WRN overexpression.

CONCLUSION

Our study reveals that DNA methylation mediated WRN inhibits apoptosis and oxidative stress of human LECs through ATM/p53 signaling pathway.

Reactive cysteine residues in the oxidative dimerization and Cu2+ induced aggregation of human γD-crystallin: Implications for age-related cataract

Cysteine (Cys) residues are major causes of crystallin disulfide formation and aggregation in aging and cataractous human lenses. We recently found that disulfide linkages are highly and partly conserved in β- and γ-crystallins, respectively, in human age-related nuclear cataract and glutathione depleted LEGSKO mouse lenses, and could be mimicked by in vitro oxidation. Here we determined which Cys residues are involved in disulfide-mediated crosslinking of recombinant human γD-crystallin (hγD). In vitro diamide oxidation revealed dimer formation by SDS-PAGE and LC-MS analysis with Cys 111-111 and C111-C19 as intermolecular disulfides and Cys 111-109 as intramolecular sites. Mutation of Cys111 to alanine completely abolished dimerization. Addition of αB-crystallin was unable to protect Cys 111 from dimerization. However, Cu²⁺-induced hγD-crystallin aggregation was suppressed up to 50% and 80% by mutants C109A and C111A, respectively, as well as by total glutathionylation. In contrast to our recently published results using ICAT-labeling method, manual mining of the same database confirmed the specific involvement of Cys111 in disulfides with no free Cys111 detectable in γD-crystallin from old and cataractous human lenses. Surface accessibility studies show that Cys111 in hγD is the most exposed Cys residue (29%), explaining thereby its high propensity toward oxidation and polymerization in the aging lens.

Influences of anterior capsule polishing on effective lens position after cataract surgery: a randomized controlled trial

To evaluate the effects of anterior capsule polishing on effective lens position (ELP) and the actual axial movements of IOLs by measuring the anterior chamber depth (ACD). This prospective randomized double-blind controlled clinical trial included patients who underwent bilateral uneventful cataract surgeries and were implanted the same IOLs (SN60WF). Extensive polishing was performed randomly in the anterior capsule of one eye with Whitman Shepherd double-ended capsule polisher, and the opposite unpolished capsule was used as the control. The ACD was measured 1 day, 1 week, 1 month, 3 months and 6 months after surgery with the anterior segment optical coherence tomography (AS-OCT). The actual axial movement of IOL was defined as the root mean square (RMS) of the change in ELP at each visit. A total of 40 eyes of 20 patients were included, and 10 patients (50%) were men. All the patients underwent uneventful surgeries without intraoperative or postoperative complications, and returned on time for measurements. The mean age of them was 70.5±7.6 years (range 56 to 79 years). No significant differences were observed between the mean ELP of the control group and the polished group (P>0.05). Nevertheless, the ELPRMS of the polished group was significantly smaller than that of the control group (P=0.005). Polishing anterior capsule intraoperatively improved the axial position stability of the IOL in the long term.

Assessment of oxidative stress and antioxidant status in age related cataract in a rural population

Oxidative stress was assesed by estimating lipid peroxidation product (LPO) in the form of thiobarbituric acid reactive substances (TBARS), enzymatic antioxidants in the form of superoxide dismutase (SOD), catalase and nonenzymatic antioxidant vitamins e.g. vitamin C, β carotene and vitamin E in either serum or plasma or erythrocytes in 190 cases of age related cataract in the age group of 50-80 years. 190 cases were grouped into three morphological types namely, 73 cases of cortical, 77 cases of posterior subcapsular and 40 cases of nuclear cataract and values of LPO and antioxidants were compared with 78 cases of age matched healthy control groups. Plasma TBARS levels were cataract cases when compared with control groups. There were no significant differences in the erythrocyte levels of catalase and plasma levels of Vit E between cataract cases and control groups. No significant changes of parameters were seen among three different morphological types of age related cataract. The present study shows that the oxidative stress may play an important role in the age related cataract.