Xanthine oxidase enzyme activity in keratoconic corneal epithelium.

PURPOSE: To assess the activity of xanthine oxidase (XO) enzyme in keratoconic corneal epithelium and to evaluate its relationship with the keratoconus (KC) severity. METHODS: This prospective and randomized study included 66 eyes of 54 KC patients who received corneal collagen cross-linking treatment and 43 eyes of 32 patients who underwent photorefractive keratectomy due to their refractive error. During surgical procedures, the corneal epithelium was mechanically scraped and gathered to analyze the XO enzyme activity spectrophotometrically. The KC group was subdivided into three groups (stages 1, 2, and 3) according to the Amsler-Krumeich classification. The results were compared between the KC and the control group and in between KC subgroups. RESULTS: No significant differences in age and gender were found between the KC and control groups (p = 0.064 and p = 0.296, respectively). The mean XO activity levels of the KC and control groups were 173.57 ± 87.61 and 223.70 ± 99.52 mIU/mg, respectively (p < 0.001). In KC group, 33 eyes were at stage 1, 19 were at stage 2, and 14 were at stage 3. No significant difference was observed between KC subgroups regarding XO activity levels (p = 0.681). CONCLUSION: In this study, our findings revealed that ultraviolet-related pro-oxidant XO enzyme may have a role in the etiopathogenesis of KC. Further studies are needed to support our result. CLINICAL TRIALS REGISTRATION: When we started this study in 2018, we did not have a "Clinical Trials Registration." However, we have ethics committee approval (date: 21. 02. 2018/No: 22).

Thiol-disulfide homeostasis as an oxidative stress marker in patients with Graves' ophthalmopathy.

Purpose: To evaluate thiol-disulfide homeostasis (TDH) and its relationship with clinical findings in patients with Graves' ophthalmopathy (GO). Methods: This study included 52 patients with GO and 34 healthy controls. Tests of TDH were conducted using the novel automated spectrophotometric method. Clinical activity score (CAS) and ophthalmopathy index were evaluated and relationships with native thiol, disulfide levels and disulfide/native thiol % ratios were analyzed. Results: The mean plasma native thiol levels in GO patients were significantly lower than that of normal controls (p = 0.013) . The mean plasma disulfide levels and disulfide/native thiol % ratio were found to be significantly higher in GO patients than in controls (p = 0.041, p = 0.022; respectively). The mean native thiol levels of active GO patients (n = 24) were significantly lower than that of patients with inactive GO (n = 28) (p = 0.044). The mean disulfide levels and disulfide/native thiol % ratios of active GO patients were significantly higher than that of patients with inactive GO (p = 0.034, p = 0.001; respectively). There was a negative correlation between native thiol and CAS (r = -0.532, p = 0.001) and a positive correlation between disulfide/native thiol % ratio and CAS (r = 0.601, p < 0.001). Conclusions: The impairment of TDH indicates the presence of oxidative stress in moderate-to-severe GO, particularly in active GO and smokers.

Efficacy and Safety of the Modified Cretan Protocol in Patients with Post-LASIK Ectasia

Objectives: To investigate the clinical efficacy and safety of the modified Cretan protocol in patients with post-laser in situ keratomileusis ectasia (PLE). Materials and Methods: In this retrospective study, 26 eyes of 16 patients with PLE were treated with the modified Cretan protocol (combined transepithelial phototherapeutic keratectomy and accelerated corneal collagen cross-linking). Visual, refractive, tomographic, and aberrometric outcomes and point spread function (PSF) were recorded preoperatively and at 6, 12, and 24 months after treatment. Results: Both uncorrected and best corrected visual acuity were stable at 24 months postoperatively compared to baseline (from 0.89±0.36 to 0.79±0.33 logarithm of the minimum angle of resolution [LogMAR] and 0.31±0.25 to 0.24±0.19 LogMAR, respectively, p>0.05 for all values). The mean K1, K2, Kmean, thinnest corneal thickness, and spherical aberration at baseline were 45.76±5.75 diopters (D), 48.62±6.17 D, 47.13±5.89 D, 433.16±56.86 µm, and -0.21±0.63 µm respectively. These values were reduced to 42.86±6.34 D, 45.92±6.74 D, 44.21±6.4 D, 391.07±54.76 µm, and -0.51±0.58 µm at 24 months postoperatively (p<0.001, p=0.002, p<0.001, p=0.001, and p=0.02, respectively). The mean spherical equivalent, manifest cylinder, Kmax, central corneal thickness, other corneal aberrations (root mean square, trefoil, coma, quatrefoil, astigmatism), and PSF remained stable (p>0.05 for all variables), while anterior and posterior elevation were significantly improved at 24 months postoperatively (p<0.001 and p=0.02, respectively). No surgical complications occurred during the 24-month follow-up. Conclusion: The modified Cretan protocol is a safe and effective treatment option for PLE patients that provides visual stabilization and significant improvement in topographic parameters during the 24-month follow-up. Further studies are needed to support our results.

Are vitamin D and vitamin D receptor levels different in children with developmental dysplasia of the hip?

INTRODUCTION: Developmental dysplasia of the hip (DDH) is a common disorder and associated with significant morbidity of the hip joint. Several risk factors have been identified for DDH. The aim of this study is to investigate whether vitamin D and vitamin D receptor (VDR) levels differ in children with DDH and whether they have an effect on DDH development. MATERIALS AND METHODS: A total of 40 (17 males, 23 females; 9 right hips, 16 left hips, 15 bilateral hips) children who were treated for developmental dysplasia and 40 (23 males, 17 females) healthy children without any musculoskeletal system and metabolic disorders were included in this study between January and June 2019. Blood samples from the DDH and control groups of children were collected to measure the serum levels of vitamin D, VDR, calcium (Ca), phosphorus (P), and alkaline phosphatase (ALP). The levels of Ca, P, and ALP were analyzed using the automated standard spectrophotometric laboratory method. The levels of vitamin D and VDR in the samples were analyzed using enzyme-linked immunoassay. RESULTS: There were no significant differences in the serum levels of Ca, P, ALP, and vitamin D between the DDH and healthy groups (Ca 9.96 ± 0.47 vs. 9.92 ± 0.48 mg/dL, respectively, p = 0.721; P 5.3 ± 0.94 vs. 4.82 ± 0.88 mg/dL, respectively, p = 0.23; ALP 252.22 ± 170.15 vs. 245.3 ± 130.93 U/L, respectively, p = 0.839). However, serum VDR levels were significantly lower in children in the DDH group (5.77 ± 3.51 ng/mL) than in the healthy control group (9.25 ± 6.43 ng/mL) (p = 0.004). CONCLUSIONS: In conclusion, we believe that low VDR levels can affect DDH regardless of the serum levels of Ca, P, ALP, and vitamin D. More comprehensive studies involving parents are needed to understand whether VDR levels mediate genetic transmission in DDH or not.

The effect of Farnesoid X receptor agonist tropifexor on liver damage in rats with experimental obstructive jaundice.

PURPOSE: To investigate experimentally the effects of Tropifexor, a farnesoid X receptor agonist, on liver injury in rats with obstructive jaundice. METHODS: Forty healthy Wistar albino female rats were divided randomly in selected groups. These groups were the sham group, control group, vehicle solution group, Ursodeoxycholic acid group and Tropifexor group. Experimental obstructive jaundice was created in all groups, except the sham one. In the blood samples obtained, aspartate transaminase (AST), alanine transaminase (ALT), alkaline phosphatase (ALP), gamma-glutamyl transferase (GGT), total bilirubin and direct bilirubin levels were established and recorded. Additionally, liver malondialdehyde, myeloperoxidase and catalase enzyme activity in the tissue samples were studied. Histopathological analysis was also performed. RESULTS: No statistical difference was found between the control group and the Tropifexor group when AST, ALT and ALP values were compared. However, it was found that the Tropifexor group had statistically significant decreases in the values of GGT, total bilirubin and direct bilirubin (p < 0.05). Additionally, Tropifexor decreased the median values of malondialdehyde and myeloperoxidase, but this difference was not statistically significant compared to the control group. Finally, the Tropifexor group was statistically significant in recurring histopathological liver damage indicators (p < 0.05). CONCLUSIONS: Tropifexor reduced liver damage due to obstructive jaundice.

Transepithelial Phototherapeutic Keratectomy Followed by Corneal Collagen Crosslinking for the Treatment of Pellucid Marginal Degeneration: Long-term Results.

PURPOSE: To evaluate visual, refractive, topographic, and aberrometric outcomes of transepithelial phototherapeutic keratectomy (PTK) + corneal collagen crosslinking in the treatment of pellucid marginal degeneration. METHODS: This retrospective study includes 20 eyes of 15 patients with pellucid marginal degeneration treated with transepithelial PTK + accelerated corneal collagen crosslinking. Visual acuity, refraction, topographic keratometry, pachymetry, and aberrations were recorded pretreatment and 6, 12, 24, and 36 months after treatment. RESULTS: Stabilization in visual acuity was observed throughout the 36 months of follow-up (P > 0.05). The cylindrical value was significantly lower (P < 0.05) during the follow-up compared with the baseline (4.97 ± 2.00, 3.86 ± 2.01, 3.92 ± 2.27, 2.87 ± 1.70, and 3.28 ± 3.12 D at the baseline and postoperative 6th, 12th, 24th, and 36th month, respectively). Spherical equivalent was significantly lower at the 24th (P = 0.02) and 36th month (P = 0.01) follow-up intervals. A significant decrease (P < 0.05) in average keratometry readings was observed in all follow-up points (47.12 ± 4.66, 46.65 ± 4.38, 46.57 ± 4.57, 46.46 ± 4.81, and 46.27 ± 4.46 D, respectively). The maximum keratometry value remained stable (P > 0.05) in all visits (64.30 ± 10.70, 63.49 ± 10.05, 62.97 ± 9.50, 63.33 ± 10.06, and 62.27 ± 10.36 D, respectively). The Baiocchi Calossi Versaci index was significantly lower (P < 0.05) at all follow-up points compared with the baseline (3.21 ± 1.93, 2.99 ± 1.96, 2.96 ± 1.93, 2.82 ± 1.95, and 2.86 ± 1.99 µm, respectively). Central and minimum corneal thicknesses were significantly lower (P ≤ 0.01) compared with the baseline throughout the follow-up. Higher order aberration, trefoil, coma, and spherical aberration values remained stable during the follow-up compared with the baseline (P > 0.05). CONCLUSIONS: The combination of transepithelial PTK with accelerated corneal collagen crosslinking seems to be an effective treatment in patients with pellucid marginal degeneration in the long-term.

Mechanical versus transepithelial phototherapeutic keratectomy epithelial removal followed by accelerated corneal crosslinking for pediatric keratoconus: Long-term results.

PURPOSE: To compare the 36-month outcomes of mechanical or transepithelial phototherapeutic keratectomy (PTK) epithelial removal before accelerated corneal crosslinking (CXL) for pediatric keratoconus. SETTING: Atatürk Training and Research Hospital, Ankara, Turkey. DESIGN: Retrospective case series. METHODS: Eyes that had accelerated CXL after mechanical (Group 1) or transepithelial PTK (Group 2) epithelial removal were evaluated preoperatively and 12, 24, and 36 months postoperatively. The uncorrected (UDVA) and corrected distance visual acuities, spherical equivalent (SE), manifest astigmatism, and corneal tomographic and aberrometric parameters were assessed. RESULTS: The study included 40 eyes of 35 consecutive keratoconus patients younger than 18 years with a 36-month follow-up. Group 1 comprised 15 patients, and Group 2 comprised 20 patients. Both groups had a significant improvement in UDVA (P = .001 and P = .02, respectively) and a significant decrease in maximum keratometry (K) and thinnest corneal thickness (all P < .001) 36 months postoperatively. The improvements in maximum K, topographic astigmatism, and spherical aberration were greater in Group 2 than in Group 1 at 12 months (P = .03, P = .01, and P = .04, respectively). After 12 months, the outcomes in the 2 groups were more similar. CONCLUSIONS: The initial visual and topographic outcomes of transepithelial PTK ablation were better than those of mechanical epithelium removal before accelerated CXL in pediatric patients with keratoconus. Over the long-term, the results were similar between the 2 groups.

Accelerated versus standard corneal collagen cross-linking in pediatric keratoconus patients: 24 months follow-up results.

PURPOSE: To compare the 24 month visual, refractive, topographic and aberrometric results of the accelerated and standard corneal collagen cross-linking (CXL) in pediatric keratoconus patients. METHODS: 87 eyes of 64 consecutive keratoconus patients under 18 years old with 24 month follow-up period following standard or accelerated CXL were included. 38 eyes received standard CXL (3 Mw/cm2, 30 min), while 49 eyes had accelerated CXL (9 mW/cm2, 10 min). Changes in the uncorrected (UCVA) and best corrected visual acuity (BCVA), spherical equivalent (SE), manifest astigmatism (MA), corneal topographic parameters, and corneal aberrations such as spherical aberration (SA), high order aberrations (HOAs), horizontal and vertical coma were evaluated. Corneal haze was graded and progression rate was assessed. RESULTS: The difference between baseline and 24 months postoperative UCVA, BCVA, SimK (keratometry)-1, SimK-2, Kmax, and the corneal aberrations were not significantly different between the two groups (p > 0.05 for all). The mean reduction in thinnest corneal pachymetry from baseline to 24 months after CXL was higher in accelerated CXL group (p = 0.007). The progression rate was 13.1% in standard and 16.3% in accelerated group (p = 0.754). There were no differences in the grade of corneal haze between the two groups (p = 0.249). No complications were observed in the both groups. CONCLUSION: The 24 month results of accelerated and standard CXL revealed that, the efficacy and safety of accelerated CXL were the same with standard CXL in pediatric keratoconus patients. As being a rapid procedure, accelerated CXL appears to be more benefical for pediatric patients.

A Novel Tool for the Assessment Oxidative Stress in Age-Related Macular Degeneration: Thiol/Disulfide Homeostasis Revisited.

PURPOSE: To investigate thiol/disulfide status using a novel automated assay in patients with age-related macular degeneration (AMD) compared to age-matched healthy controls. METHODS: A total of 64 AMD patients [51 (79%) non-exudative, 13 (21%) exudative AMD] and 21 age-matched healthy control subjects were enrolled in this study. Plasma total thiol, native thiol, disulfide levels were measured and native thiol/disulfide ratio (TDR) was calculated using a novel spectrophotometric assay. RESULTS: Patients with AMD had significantly lower levels of total thiol (434.8 ± 7.0 µmol/L vs. 472.2 ± 7.9 µmol/L, p < 0.001), native thiol (393.6 ± 6.5 µmol/L vs. 437.5 ± 7.1 µmol/L, p = 0.004) compared to healthy controls. However, plasma disulfide levels were higher in AMD patients (20.6 ± 0.9 µmol/L vs. 17.3 ± 1.3 µmol/L, p = 0.113) compared to healthy controls. The TDR was not statistically different between the early AMD group and healthy controls (24.2 ± 2.3 vs. 29.5 ± 3.1, p = 0.345). However, intermediate and advanced stage AMD groups had significantly lower levels of TDR compared to healthy controls (21.6 ± 2.6 vs. 29.5 ± 3.1, p = 0.023 and 20.3 ± 1.2 vs. 29.5 ± 3.1, p = 0.005, respectively). Native TDR was significantly lower in patients with exudative and non-exudative AMD (19.9 ± 2.3 vs. 29.5 ± 3.1, p = 0.024 and 21.8 ± 1.14 vs. 29.47 ± 3.1 respectively, p = 0.011). CONCLUSION: A greater extent of thiol consumption occurred in AMD patients compared to age-matched healthy controls. However, despite the similar levels of total thiol levels between several grades of AMD, the plasma native TDR value was decreased in accordance with the severity of the disease, which reflected the disease grade better.

The effect of Farnesoid X receptor agonist tropifexor on liver damage in rats with experimental obstructive jaundice

ABSTRACT Purpose: To investigate experimentally the effects of Tropifexor, a farnesoid X receptor agonist, on liver injury in rats with obstructive jaundice. Methods: Forty healthy Wistar albino female rats were divided randomly in selected groups. These groups were the sham group, control group, vehicle solution group, Ursodeoxycholic acid group and Tropifexor group. Experimental obstructive jaundice was created in all groups, except the sham one. In the blood samples obtained, aspartate transaminase (AST), alanine transaminase (ALT), alkaline phosphatase (ALP), gamma-glutamyl transferase (GGT), total bilirubin and direct bilirubin levels were established and recorded. Additionally, liver malondialdehyde, myeloperoxidase and catalase enzyme activity in the tissue samples were studied. Histopathological analysis was also performed. Results: No statistical difference was found between the control group and the Tropifexor group when AST, ALT and ALP values were compared. However, it was found that the Tropifexor group had statistically significant decreases in the values of GGT, total bilirubin and direct bilirubin (p < 0.05). Additionally, Tropifexor decreased the median values of malondialdehyde and myeloperoxidase, but this difference was not statistically significant compared to the control group. Finally, the Tropifexor group was statistically significant in recurring histopathological liver damage indicators (p < 0.05). Conclusions: Tropifexor reduced liver damage due to obstructive jaundice.