Tear fluid small molecular antioxidants profiling shows lowered glutathione in keratoconus

Saijyothi, Aluru Venkata; Fowjana, Jenofar; Subramanian, Madhumathi; Mahadevan, Rajeshwari; Maruthamuthu, Thennarasu; Prema, P.; Angayarkanni, Narayanasamy

doi:10.1016/j.exer.2012.07.010

Cited by 47 publications

(31 citation statements)

References 30 publications

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“…The concentrations of ions were in the mM range, the largest concentration was that of chloride (99.9 mM) and sodium cation (143.6 mM). The calculated GSH concentration was 34.6 µM that is in agreement with the previously published data—the concentration of GSH that was found previously in tear samples ranged from 12.6 to 183.3 µM . The analysis of EBC in Fig.…”

Section: Resultssupporting

confidence: 91%

Optimization of background electrolyte composition for simultaneous contactless conductivity and fluorescence detection in capillary electrophoresis of biological samples

et al. 2019

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In this article, optimization of BGE for simultaneous separation of inorganic ions, organic acids, and glutathione using dual C4D‐LIF detection in capillary electrophoresis is presented. The optimized BGE consisted of 30 mM 2‐[4‐(2‐hydroxyethyl)piperazin‐1‐yl]ethanesulfonic acid, 15 mM 2‐amino‐2‐hydroxymethyl‐propane‐1,3‐diol, and 2 mM 18‐crown‐6 at pH 7.2 and allowed simultaneous separation of ten inorganic anions and cations, three organic acids and glutathione in 20 min. The samples were injected hydrodynamically from both capillary ends using the double‐opposite end injection principle. Sensitive detection of anions, cations, and organic acids with micromolar LODs using C4D and simultaneously glutathione with nanomolar LODs using LIF was achieved in a single run. The developed BGE may be useful in analyses of biological samples containing analytes with differing concentrations of several orders of magnitude that is not possible with single detection mode.

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Section: Resultssupporting

confidence: 91%

Optimization of background electrolyte composition for simultaneous contactless conductivity and fluorescence detection in capillary electrophoresis of biological samples

et al. 2019

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“…Arnal and co-authors (Arnal et al, 2011) reported a decreased glutathione content and overall antioxidant capacity in KC corneas. Saijyothi and co-authors (Saijyothi et al, 2012)reported decreased levels of glutathione in KC tear film linking oxidative stress in KC corneas to tear film. We recently reported oxidative stress in HKCs while cultured in a conventional 2D system or our 3D model (Karamichos et al, 2014).…”

Section: Discussionmentioning

confidence: 99%

Tear metabolite changes in keratoconus

Karamichos

Zieske

Sejersen

et al. 2015

Experimental Eye Research

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While efforts have been made over the years, the exact cause of keratoconus (KC) remains unknown. The aim of this study was to identify alterations in endogenous metabolites in the tears of KC patients compared with age-matched healthy subjects. Three groups were tested: 1) Age-matched controls with no eye disease (N=15), 2) KC – patients wearing Rigid Gas permeable lenses (N=16), and 3) KC – No Correction (N=14). All samples were processed for metabolomics analysis using LC-MS/MS. We identified a total of 296 different metabolites of which >40 were significantly regulated between groups. Glycolysis and gluconeogenesis had significant changes, such as 3-phosphoglycerate and 1,3 diphopshateglycerate. As a result the citric acid cycle (TCA) was also affected with notable changes in Isocitrate, aconitate, malate, and acetylphosphate, up regulated in Group 2 and/or 3. Urea cycle was also affected, especially in Group 3 where ornithine and aspartate were up-regulated by at least 3 fold. The oxidation state was also severely affected. Groups 2 and 3 were under severe oxidative stress causing multiple metabolites to be regulated when compared to Group 1. Group 2 and 3, both showed significant down regulation in GSH-to-GSSG ratio when compared to Group 1. Another indicator of oxidative stress, the ratio of lactate – pyruvate was also affected with Groups 2 and 3 showing at least a 2-fold up regulation. Overall, our data indicate that levels of metabolites related to urea cycle, TCA cycle and oxidative stress are highly altered in KC patients.

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“…Similarly, a number of clinical studies have found that the tears of patients with keratoconus had lower levels of glutathione (an antioxidant that compensates increased oxidative stress), higher levels of proteolytic activity, and overexpression of several matrix metalloproteinases compared with those of the healthy controls. 23,24 In conclusion, although previous ex vivo studies have provided evidence that local oxidative stress has a role in the pathogenesis of keratoconus, this is the first clinical study to evaluate the systemic oxidative and antioxidative status of the patients with keratoconus. The higher serum oxidant status and OSI indicate that systemic oxidative stress might contribute to the development of keratoconus, whereas our findings need to be confirmed by further studies in a larger population.…”

Section: Discussionmentioning

confidence: 99%

Increased systemic oxidative stress in patients with keratoconus

Toprak

Küçükatay

Yıldırım

et al. 2013

Eye

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Purpose To establish the effect of systemic oxidative stress on the pathogenesis of keratoconus by measuring serum total oxidant status (TOS) and total antioxidant status (TAS) in patients with keratoconus. Methods Twenty-five patients with keratoconus (keratoconus group) and 25 age-sex-matched healthy subjects (control group) were enrolled in the study. Exclusion criteria were smoking habit, history of any other corneal pathology, systemic disease or inflammation, and current antioxidant or anti-inflammatory therapies. All participants underwent a detailed ophthalmological examination and corneal topography. Serum samples were obtained from all participants. Oxidative stress markers (TAS and TOS) were measured using a commercial kit and oxidative stress index (OSI) was calculated. Results The study comprised 25 patients with keratoconus (mean age of 26.4 ± 1.7 years) and 25 healthy control subjects (mean age of 26.6 ± 1.7 years) (P40.05). The serum TOS and OSI values were significantly higher in patients with keratoconus compared with those of the controls (P ¼ 0.036 and 0.037, respectively). However, serum TAS did not show significant difference between the keratoconus and control groups (P ¼ 0.497). Conclusions The higher levels of serum oxidant status and OSI in patients with keratoconus suggest that systemic oxidative stress might be involved in the pathogenesis of keratoconus.

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Tear fluid small molecular antioxidants profiling shows lowered glutathione in keratoconus

Cited by 47 publications

References 30 publications

Optimization of background electrolyte composition for simultaneous contactless conductivity and fluorescence detection in capillary electrophoresis of biological samples

Optimization of background electrolyte composition for simultaneous contactless conductivity and fluorescence detection in capillary electrophoresis of biological samples

Tear metabolite changes in keratoconus

Increased systemic oxidative stress in patients with keratoconus

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