Assessment of OCT-Based Macular Curvature and Its Relationship with Macular Microvasculature in Children with Anisomyopia

INTRODUCTION

To evaluate the intraocular differences in optical coherence tomography (OCT)-based macular curvature index (MCI) among children with anisomyopia and to investigate the relationship between MCI and the macular microvasculature.

METHODS

Fifty-two schoolchildren with anisometropia > 2.00 D were enrolled and underwent comprehensive examinations including cycloplegic refraction, axial length (AL), and swept source OCT/OCT angiography. OCT-based MCIs were determined from horizontal and vertical B-scans by a customized curve fitting model in MATLAB R2022 at 1-mm-, 3-mm-, and 6-mm-diameter circles at fovea. Characteristics and topographic variation of MCI was analyzed, and the relationships with microvascularity and its associated factors were investigated.

RESULTS

MCI achieved high reliability and repeatability. There were overall larger MCIs in the more myopic eyes than the less myopic eyes in 1-mm-, 3-mm-, and 6-mm-diameter circles at fovea (all p < 0.001). For the topographic variation, horizontal MCI was significantly greater than vertical MCI (all p < 0.001), and was the largest in 6-mm circle, followed by 3-mm and 1-mm circles. Stronger correlation of horizontal MCI with myopic severity than vertical MCI was found. Partial Pearson's correlation found MCI was negatively associated with deep capillary plexus (DCP) vessel density (p = 0.016). Eyes with a higher MCI in a 6-mm circle were more likely to have longer AL (p < 0.001), lower DCP vessel density (p = 0.037), and thinner choroidal thickness (ChT) (p = 0.045).

CONCLUSION

Larger MCI was found in the more myopic eyes of children with anisomyopia and was significantly associated with smaller DCP density, suggesting that MCI was an important indicator of myopia-related retinal microvascularity change, and it could be a valuable metric for myopia assessment in children.

[Comparison of the efficacy of different surgical strategies in the treatment of patients with initially resectable gastric cancer liver metastases]

Objective: To examine the impact of varied surgical treatment strategies on the prognosis of patients with initial resectable gastric cancer liver metastases (IR-GCLM). Methods: This is a retrospective cohort study. Employing a retrospective cohort design, the study selected clinicopathological data from the national multi-center retrospective cohort study database, focusing on 282 patients with IR-GCLM who underwent surgical intervention between January 2010 and December 2019. There were 231 males and 51 males, aging (M(IQR)) 61 (14) years (range: 27 to 80 years). These patients were stratified into radical and palliative treatment groups based on treatment decisions. Survival curves were generated using the Kaplan-Meier method and distinctions in survival rates were assessed using the Log-rank test. The Cox risk regression model evaluated HR for various factors, controlling for confounders through multivariate analysis to comprehensively evaluate the influence of surgery on the prognosis of IR-GCLM patients. A restricted cubic spline Cox proportional hazard model assessed and delineated intricate associations between measured variables and prognosis. At the same time, the X-tile served as an auxiliary tool to identify critical thresholds in the survival analysis for IR-GCLM patients. Subgroup analysis was then conducted to identify potential beneficiary populations in different surgical treatments. Results: (1) The radical group comprised 118 patients, all undergoing R0 resection or local physical therapy of primary and metastatic lesions. The palliative group comprised 164 patients, with 52 cases undergoing palliative resections for gastric primary tumors and liver metastases, 56 cases undergoing radical resections for gastric primary tumors only, 45 cases undergoing palliative resections for gastric primary tumors, and 11 cases receiving palliative treatments for liver metastases. A statistically significant distinction was observed between the groups regarding the site and the number of liver metastases (both P<0.05). (2) The median overall survival (OS) of the 282 patients was 22.7 months (95%CI: 17.8 to 27.6 months), with 1-year and 3-year OS rates were 65.4% and 35.6%, respectively. The 1-year OS rates for patients in the radical surgical group and palliative surgical group were 68.3% and 63.1%, while the corresponding 3-year OS rates were 42.2% and 29.9%, respectively. A comparison of OS between the two groups showed no statistically significant difference (P=0.254). Further analysis indicated that patients undergoing palliative gastric cancer resection alone had a significantly worse prognosis compared to other surgical options (HR=1.98, 95%CI: 1.21 to 3.24, P=0.006). (3) The size of the primary gastric tumor significantly influenced the patients' prognosis (HR=2.01, 95%CI: 1.45 to 2.79, P<0.01), with HR showing a progressively increasing trend as tumor size increased. (4) Subgroup analysis indicates that radical treatment may be more effective compared to palliative treatment in the following specific cases: well/moderately differentiated tumors (HR=2.84, 95%CI 1.49 to 5.41, P=0.001), and patients with liver metastases located in the left lobe of the liver (HR=2.06, 95%CI 1.19 to 3.57, P=0.010). Conclusions: In patients with IR-GCLM, radical surgery did not produce a significant improvement in the overall prognosis compared to palliative surgery. However, within specific patient subgroups (well/moderately differentiated tumors, and patients with liver metastases located in the left lobe of the liver), radical treatment can significantly improve prognosis compared to palliative approaches.

Prediction of Myopia Eye Axial Elongation With Orthokeratology Treatment via Dense I2I Based Corneal Topography Change Analysis

While orthokeratology (OK) has shown effective to slow the progression of myopia, it remains unknown how spatially distributed structural stress/tension applying to different regions affects the change of corneal geometry, and consecutive the outcome of myopia control, at fine-grained detail. Acknowledging that the underlying working mechanism of OK lens is essentially mechanics induced refractive parameter reshaping, in this study, we develop a novel mechanics rule guided deep image-to-image learning framework, which densely predicts patient's corneal topography change according to treatment parameters (lens geometry, wearing time, physiological parameters, etc.), and consecutively predicts the influence on eye axial length change after OK treatment. Encapsulated in a U-shaped multi-resolution map-to-map architecture, the proposed model features two major components. First, geometric and wearing parameters of OK lens are spatially encoded with convolutions to form a multi-channel input volume/tensor for latent encodings of external stress/tension applied to different regions of cornea. Second, these external latent force maps are progressively down-sampled and injected into this multi-scale architecture for predicting the change of corneal topography map. At each feature learning layer, we formally derive a mathematic framework that simulates the physical process of corneal deformation induced by lens-to-cornea interaction and corneal internal tension, which is reformulated into parameter learnable cross-attention/self-attention modules in the context of transformer architecture. A total of 1854 eyes of myopia patients are included in the study and the results show that the proposed model precisely predicts corneal topography change with a high PSNR as 28.45dB, as well as a significant accuracy gain for axial elongation prediction (i.e., 0.0276 in MSE). It is also demonstrated that our method provides interpretable associations between various OK treatment parameters and the final control effect. Our project code package is available at https://github.com/Rongdingyi/PhyIntNet.

[Quality control of lymph node dissection for locally advanced gastric cancer]

Numerous studies have confirmed that D2 lymphadenectomy is the standard surgery for locally advanced gastric cancer. Standardized lymph node dissection plays a crucial role in ensuring surgical quality and efficacy. It is recommended to perform D2 lymph node dissection according to the 6th edition of the Japanese gastric cancer treatment guidelines. For lymph nodes beyond the scope of D2 lymph node dissection, such as No.10, 13, 14v, 16 and mediastinal lymph nodes, selective D2+ lymph node dissection can be performed, which may be advantageous for some patients. Currently, omentectomy is the standard surgical procedure for locally advanced gastric cancer. However, the clinical significance of gastrectomy with preservation of the greater omentum requires further validation through large-scale clinical trials. Standardized ex vivo lymph node dissection is important for accurate postoperative staging, and it is recommended to harvest more than 30 lymph nodes to avoid staging deviation.

Change in three-dimensional choroidal vessel network after AR device assisted 1-hour visual task in 2D/3D mode in young healthy subjects

PURPOSE

The purpose of the study was to investigate the changes of choroidal blood perfusion in different layers and quadrants and its possible related factors after 1 h visual task by augmented reality (AR) device in two-dimensional (2D) and three-dimensional (3D) mode, respectively.

METHODS

Thirty healthy subjects aged 22-37 years watched the same video source in 2D and 3D mode separately using AR glasses for 1 h with a one-week interval. Swept-source optical coherence tomography angiography (SS-OCTA) was performed before and immediately after watching to acquire choroidal thickness (ChT), three-dimensional choroidal vascularity index (CVI) of large- and middle-sized choroidal vessels and choriocapillaris flow voids (FV%) at macular and peripapillary area. Near point of accommodation (NPA) and accommodative facility (AF) were examined to evaluate the accommodative ability. Pupil diameters by infrared-automated pupillometer under scotopic, mesopic and photopic condition were also obtained.

RESULTS

Compared with pre-visual task, the subfoveal CVI decreased from 0.406 ± 0.097 to 0.360 ± 0.102 after 2D watching (p < 0.001) and to 0.368 ± 0.102 after 3D watching (p = 0.002). Pupil sizes under different illuminance conditions became smaller after both 2D and 3D watching (all p < 0.001). AF increased after both 2D and 3D watching (both p < 0.05). NPA receded in post-3D watching (p = 0.017) while a not significant tendency was observed in post-2D.

CONCLUSION

A reduction in subfoveal choroidal blood flow accompanied with pupil constriction was observed immediately after 1 h visual task using AR glasses in 2D and 3D mode. Accommodative facility improved after 2D and 3D watching with AR glasses, whereas decrease in the maximum accommodation power was only found in 3D mode.

[Clinical implications of Naples prognostic scores in patients with resectable Siewert type II-III adenocarcinoma of the esophagogastric junction]

Objective: To evaluate the clinical value of preoperative Naples prognostic scores (NPS) in patients with resectable Siewert type II-III esophagogastric junction adenocarcinoma (AEG). Methods: In this retrospective observational study we collected and analyzed relevant data of patients with Siewert Type II-III AEG treated in the Department of Gastric Cancer, Tianjin Medical University Cancer Institute and Hospital from January 2014 to December 2018. NPS were calculated using preoperative albumin concentration, total cholesterol concentration, neutrophil/lymphocyte ratio, and lymphocyte/monocyte ratio and used to allocate patients into three groups: NTS-0 (0 points), NTS-1 (1-2 points) and NTS-2 (3-4 points). Kaplan-Meier was used to calculate disease-free survival (DFS) and overall survival (OS) in each NPS group and the log-rank test to compare these groups. Univariate and multivariate survival analyes were performed using the Cox regression model. Time-dependent receiver operating characteristic curves were constructed to compare the relationships between four commonly used tools for evaluating inflammatory responses and nutritional status:NPS, systemic inflammatory response scores, nutrient control status (CONUT), and prognostic nutrition index (PNI). Results: The study cohort comprised 221 patients with AEG of median age 63.0 (36.0-87.0) years. There were 190 men (86.0%) and 31 women (14.0%). As to pTNM stage, 47 patients (21.3%) had Stage I disease, 68 (30.8%) Stage II, and 106 (48.0%) Stage III. One hundred and forty-seven patients (66.5%) had Siewert Type II disease and 74 (33.5%) Siewert type III. There were 45 patients (20.4%) in the NPS-0, 142 (64.2%) in the NPS-1 and 34 (15.4%) in the NPS-2 groups. Higher NPS scores were significantly associated with older patients (χ²=5.056, P=0.027) and higher TNM stages (H=5.204,P<0.001). The median follow-up was 39 (6-105) months; 16 patients (7.2%) were lost to follow-up. The median OS in the NPS-0, NPS-1, and NPS-2 groups were 78.4, 63.1, and 37.0 months, respectively; these differences are statistically significant (P=0.021). Univariate and multivariate Cox regression analysis identified the following as independently and significantly associated with OS in patients with Siewert Type II-III: TNM stage (Stage II: HR=2.182, 95%CI: 1.227-3.878, P=0.008; Stage III: HR=3.534, 95%CI: 1.380-6.654, P<0.001), tumor differentiation (G3: HR=1.995, 95%CI: 1.141-3.488, P=0.015), vascular invasion (HR=2.172, 95%CI: 1.403-3.363, P<0.001), adjuvant chemotherapy (HR=0.326, 95%CI: 0.200-0.531, P<0.001), NPS (NPS-1: HR=2.331, 95%CI: 1.371-3.964, P=0.002; NPS-2: HR=2.494, 95%CI: 1.165-5.341, P=0.019), SIS group (NPS-1: HR=2.170, 95%CI: 1.244-3.784, P=0.006; NPS-2: HR=2.291, 95%CI: 1.052-4.986, P=0.037), and CONUT (HR=1.597, 95% CI: 1.187-2.149, P=0.038). The median DFS in the NPS-0, NPS-1, and NPS-2 groups was 68.6, 52.5, and 28.3 months, respectively; these differences are statistically significant (P=0.009). Univariate and multivariate Cox regression analysis identified the following as independently and significantly associated with DFS in patients with Siewert Type II-III AEG: TNM stage (StageⅡ: HR=2.789, 95%CI:1.210-6.428, P=0.016; Stage III: HR=10.721, 95%CI:4.709-24.411, P<0.001), adjuvant chemotherapy (HR=0.640, 95% CI: 0.432-0.946, P=0.025), and NPS (NPS-1: HR=1.703, 95%CI: 1.043-2.782, P=0.033; NPS-2: HR=3.124, 95%CI:1.722-5.666, P<0.001). Time-dependent receiver operating characteristic curves showed that NPS was more accurate in predicting OS and DFS in patients with Siewert Type II-III AEG than were systemic inflammatory response scores, CONUT, or PNI scores. Conclusion: NPS is associated with age and TNM stage, is an independent prognostic factor in patients who have undergone resection of Siewert type II-III AEG, and is better than SIS, CONUT, or PNI in predicting survival.

High myopia is protective against diabetic retinopathy in the participants of the National Health and Nutrition Examination Survey

PURPOSE

To investigate the association of subjects with refractive error and diabetic retinopathy (DR) in the United States comparing results between different race groups.

METHODS

All data were derived from National Health and Nutrition Examination Survey (NHANES) from 2005 to 2008. The data were divided into four groups (emmetropia, mild myopia, high myopia, hypertropia) according to the spherical equivalent (SE), and those who met the enrollment conditions were selected as the study subjects. Multivariable logistic regression analysis was used to evaluate the relationship between refractive error and diabetic retinopathy risk.

RESULTS

A total of 1317 participants were included in the study, including 331 participants with diabetic retinopathy, and 986 without diabetic retinopathy. After adjustment for potential confounders, subjects with high myopia were associated with a lower risk of diabetic retinopathy. The odds ratio (OR) was 0.44, 95% confidence interval (CI): (0.20-0.96), P-value = 0.040 in the multivariate regression analysis. Subgroup analyses showed that subjects with high myopia in the non-Hispanic Black group were associated with decreased odds of diabetic retinopathy. (OR was 0.20, and 95% CI: 0.04-0.95, P-value = 0.042).

CONCLUSION

The results show that high myopia is associated with diabetic retinopathy in diabetic patients.

[Prognostic value of a predictive model comprising preoperative inflammatory response and nutritional indexes in patients with gastric cancer]

Objective: To investigate the prognostic value of preoperative inflammatory and nutritional condition detection in the postoperative survival, and establish a prognostic model for predicting the survival of patients with gastric cancer. Methods: The clinicopathological data of 1123 patients with gastric cancer who had undergone radical gastrectomy in Tianjin Medical University Cancer Institute & Hospital from January 2005 to December 2014 were retrospectively analyzed. Patients with history of other malignancy, with history of gastrectomy, who had received preoperative treatment, who died during the initial hospital stay or first postoperative month, and missing clinical and pathological information were excluded. Cox univariate and multivariate analyses were used to identify independent clinicopathological factors associated with the survival of these gastric cancer patients. Cox univariate analysis was used to identify preoperative inflammatory and nutritional indexes related to the survival of patients with gastric cancer after radical gastrectomy. Moreover, the Cox proportional regression model for multivariate survival analysis (forward stepwise regression method based on maximum likelihood estimation) was used. The independent clinicopathological factors that affect survival were incorporated into the following three new prognostic models: (1) an inflammatory model: significant preoperative inflammatory indexes identified through clinical and univariate analysis; (2) a nutritional model: significant preoperative nutritional indexes identified through clinical and univariate analysis; and (3) combined inflammatory/nutritional model: significant preoperative inflammatory and nutritional indexes identified through clinical and univariate analysis. A model that comprised only pT and pN stages in tumor TNM staging was used as a control model. The integrated area under the receiver operating characteristic curve (iAUC) and C-index were used to evaluate the discrimination of the model. Model fitting was evaluated by Akaike information criterion analysis. Calibration curves were used to assess agreement between the predicted probabilities and actual probabilities at 3-year or 5-year overall survival (OS). Results: The study cohort comprised 1 123 patients with gastric cancer. The mean age was 58.9±11.6 years, and 783 were males. According to univariate analysis, age, surgical procedure, extent of lymph node dissection, tumor location, maximum tumor size, number of examined lymph nodes, pT stage, pN stage, and nerve invasion were associated with 5-year OS after radical gastrectomy for gastric cancer (all P<0.050). Multivariate analysis further identified age (HR: 1.18, 95%CI: 1.03-1.36, P=0.019), maximum tumor size (HR: 1.19, 95%CI: 1.03-1.38, P=0.022), number of examined lymph nodes (HR: 0.79, 95%CI: 0.68-0.92, P=0.003), pT stage (HR: 1.40, 95%CI: 1.26-1.55, P<0.001) and pN stage (HR: 1.28, 95%CI: 1.21-1.35, P<0.001) as independent prognostic factors for OS of gastric cancer patients. Additionally, according to univariate survival analysis, the preoperative inflammatory markers of neutrophil count, percentage of neutrophils, neutrophil/lymphocyte ratio, platelet/neutrophil ratio and preoperative nutritional indicators of serum albumin and body mass index were potential prognostic factors for gastric cancer (all P<0.05). On the basis of the above results, three models for prediction of prognosis were constructed. Variables included in the three models are as follows. (1) Inflammatory model: age, maximum tumor size, number of examined lymph nodes, pT stage, pN stage, percentage of neutrophils, and neutrophil-lymphocyte ratio; (2) nutritional model: age, maximum tumor size, number of examined lymph nodes, pT stage, pN stage, and serum albumin; and (3) combined inflammatory/nutritional model: age, maximum tumor size, number of examined lymph nodes, pT stage, pN stage, percentage of neutrophils, neutrophil-lymphocyte ratio, and serum albumin. We found that the predictive accuracy of the combined inflammatory/nutritional model, which incorporates both inflammatory indicators and nutrition indicators (iAUC: 0.676, 95% CI: 0.650-0.719, C-index: 0.698),was superior to that of the inflammation model (iAUC: 0.662, 95% CI: 0.673-0.706;C-index: 0.675), nutritional model (iAUC: 0.666, 95% CI: 0.642-0.698, C-index: 0.672), and TNM staging control model (iAUC: 0.676, 95% CI: 0.650-0.719, C-index: 0.658). Furthermore, the combined inflammatory/nutritional model had better fitting performance (AIC: 10 762) than the inflammatory model (AIC: 10 834), nutritional model (AIC: 10 810), and TNM staging control model (AIC: 10 974). Conclusions: Preoperative percentage of neutrophils, NLR, and BMI have predictive value for the prognosis of gastric cancer patients. The inflammatory / nutritional model can be used to predict the survival and prognosis of gastric cancer patients on an individualized basis.

Perfluorohexyloctane Eye Drops for Dry Eye Disease Associated With Meibomian Gland Dysfunction in Chinese Patients: A Randomized Clinical Trial

Importance

Meibomian gland dysfunction (MGD) is a leading cause of evaporative dry eye disease (DED). Medical and surgical management for DED is limited; therefore, new treatment options are sought.

Objective

To evaluate the efficacy and safety of SHR8058 (perfluorohexyloctane) eye drops in Chinese patients with DED associated with MGD through 57 days.

Design, Setting, and Participants

This was a randomized, multicenter, double-masked, saline-controlled, phase 3 clinical trial conducted from February 4, 2021, to September 7, 2022. Patients were recruited from the departments of ophthalmology in 15 hospitals in China. Patients with DED associated with MGD were enrolled between February 4 and July 1, 2021. The diagnosis was based on patient complaint of DED symptoms, an ocular surface disease index of 25 or higher, tear film break-up time of 5 seconds or less, Schirmer I test without anesthesia results of 5 mm or more at 5 minutes, total corneal fluorescein staining (tCFS) score of 4 to 11, and an MGD score of 3 or higher.

Interventions

Eligible participants were randomly assigned 1:1 to receive perfluorohexyloctane eye drops or 0.6% sodium chloride [NaCl]) 4 times per day.

Main Outcomes and Measures

The primary end points were the changes from baseline in tCFS and eye dryness scores at day 57.

Results

A total of 312 participants were included in the analysis: 156 (mean [SD] age, 45.4 [15.2] years; 118 female [75.6%]) in the perfluorohexyloctane group and 156 (mean [SD] age, 43.7 [15.1] years; 127 female [81.4%]) in the NaCl group. Both primary end points were achieved, ie, changes from baseline at day 57 of tCFS score (mean [SD], -3.8 [2.7] vs -2.7 [2.8]) and eye dryness score (mean [SD], -38.6 [21.9] vs -28.3 [20.8]) in the perfluorohexyloctane group were superior to the control group, with estimated mean differences of -1.14 (95% CI, -1.70 to -0.57; P < .001) and -12.74 (95% CI, -17.20 to -8.28, P < .001), respectively. Improvements on both end points appeared to be noted on day 29 and day 15, respectively, and maintained through day 57. Compared with the control, perfluorohexyloctane eye drops also alleviated symptoms including pain (mean [SD] tCFS score, 26.7 [23.7] vs -18.7 [22.5]; P = .003), awareness of DED symptoms (mean [SD] tCFS score, -38.1 [25.1] vs -23.7 [27.6]; P < .001), and frequency of dryness (mean [SD] tCFS score, -43.3 [23.8] vs -29.1 [24.8]; P < .001). Treatment-emergent adverse events occurred in 34 participants (21.8%) and 40 participants (25.6%) in the perfluorohexyloctane and control groups, respectively.

Conclusions and Relevance

Results of this randomized clinical trial demonstrate that perfluorohexyloctane eye drops significantly ameliorated the signs and symptoms of DED associated with MGD with a rapid efficacy as well as satisfactory tolerability and safety through 57 days. Findings support the use of these eye drops if results can be confirmed independently and over longer time periods.

Trial Registration

ClinicalTrials.gov Identifier: NCT05515471.

MedMNIST v2 - A large-scale lightweight benchmark for 2D and 3D biomedical image classification

We introduce MedMNIST v2, a large-scale MNIST-like dataset collection of standardized biomedical images, including 12 datasets for 2D and 6 datasets for 3D. All images are pre-processed into a small size of 28 × 28 (2D) or 28 × 28 × 28 (3D) with the corresponding classification labels so that no background knowledge is required for users. Covering primary data modalities in biomedical images, MedMNIST v2 is designed to perform classification on lightweight 2D and 3D images with various dataset scales (from 100 to 100,000) and diverse tasks (binary/multi-class, ordinal regression, and multi-label). The resulting dataset, consisting of 708,069 2D images and 9,998 3D images in total, could support numerous research/educational purposes in biomedical image analysis, computer vision, and machine learning. We benchmark several baseline methods on MedMNIST v2, including 2D/3D neural networks and open-source/commercial AutoML tools. The data and code are publicly available at https://medmnist.com/ .

The Impact of Corneal Epithelial Thickening and Inhomogeneity on Corneal Aberrations After Small Incision Lenticule Extraction

PURPOSE

To investigate the corneal epithelial remodeling profile after small incision lenticule extraction (SMILE), the correlated explanatory variables, and its potential impact on corneal higher order aberrations (HOAs).

METHODS

This single-center study prospectively evaluated 75 right eyes of 75 patients scheduled for SMILE. An anterior segment optical coherence tomography device was used to automatically obtain central 6-mm corneal epithelial thickness (ET), total corneal HOAs, and individual Zernike components before and after surgery. The ET inhomogeneity over the central 3- and 6-mm cornea was quantified with coefficient of variance (CV).

RESULTS

Both ET and CV significantly increased 1 month postoperatively (all P < .05). The stepwise multiple regression analysis showed that ET and CV were significantly correlated with preoperative ET and CV, respectively (all P < .01). The corrected spherical equivalent also significantly influenced ET and CV (all P < .01). Over the central 6-mm zone, the alterations of total corneal HOAs and individual Zernike components such as vertical coma (Z7) and spherical aberration (Z12, Z24) were significantly correlated with ET and CV (all P < .05).

CONCLUSIONS

The SMILE-induced epithelial remodeling involved both ET and ET inhomogeneity. The modulation was associated with preoperative and treatment parameters, and exerted a significant impact on corneal HOA alterations especially over the central 6-mm cornea. Together with the amount of correction and corneal curvature gradient change, preoperative assessment of ET and ET inhomogeneity might help predict postoperative epithelial remodeling. [J Refract Surg. 2023;39(1):23-32.].

Changes in Dimensions and Functions of Crystalline Lens in High Myopia Using CASIA2 Optical Coherence Tomography

INTRODUCTION

Crystalline lens is the major dioptric component and varies with refractive status. In this study, we aim to evaluate the changes of dimensions and functions of crystalline lens in high myopia (HM) and its correlated variables using CASIA2 swept-source optical coherence tomography.

METHODS

One hundred and thirty eligible eyes of myopic patients from 18 to 40 years old were enrolled and divided into low-to-moderate myopia (LMM) and HM groups according to spherical equivalent (SE). Anterior segment features, including lens thickness (LT), anterior radius of curvature (ARC), posterior radius of curvature (PRC), anterior chamber depth (ACD), and lens tilt were obtained by CASIA2. Lens power was calculated using Bennett's formula. Sixty-seven participants were imaged at the static state and the accommodative state induced by -3 diopter (D) stimulus.

RESULTS

Compared to the LMM group, the HM group exhibited a significantly reduction in LT, ARC, and lens tilt (all p < 0.01). Each parameter correlated positively with SE (all p < 0.01). Lens power increased with LT and tilt (r = 0.42, 0.45) but decreased with ARC and axial length (AL) (r = -0.37, -0.62) among highly myopic eyes. Multivariate regression analysis revealed that lower lens power appeared to be independently associated with axial elongation in both groups (LMM: β = -1.124, p = 0.002; HM: β = -1.603, p < 0.001, respectively). Decreases in ARC and ACD were accompanied by accommodative response in each group, while PRC reduced during accommodation (p = 0.009) only in HM.

CONCLUSIONS

Young adults with HM presented a thinner thickness, smaller tilt, less lens power, and higher accommodative response. Lens shape was closely associated with SE; however, AL was a meaningful indicator of lens power.

Combination Therapy of 0.1% Fluorometholone and 0.05% Azelastine in Eyes with Severe Allergic Conjunctival Diseases: A Randomized Controlled Trial

This study sought to evaluate the efficacy of the isolated use of fluorometholone compared with the combined use of azelastine and fluorometholone for the treatment of severe allergic conjunctival disease (ACD). One hundred and eleven patients with severe ACD were randomized into two groups: one treated with topical 0.1% fluorometholone combined with 0.05% azelastine and the other with 0.1% fluorometholone alone. The Ocular Surface Disease Index (OSDI) and the signs of keratopathy, palpebral conjunctiva papillae and conjunctival congestion were scored before and at one, two and six weeks after treatment and compared between the groups. The intra-ocular pressure (IOP) was also monitored. There were no significant differences between the groups in the baseline mean scores of signs and OSDI scores, which gradually improved at all visits after therapy in both groups. Although the time effect was significant for all the parameters (all p < 0.001), the reduction in corneal involvement scores from week 2 to week 6 was insignificant in both groups (p = 0.460 for the steroids group and p = 0.074 for the combination group). All signs and symptoms were significantly more improved in the combination group than in the isolated group at each control visit. IOP remained stable at all visits (all p < 0.001), except one patient in each group had elevated IOP over 21 mmHg. While both the isolated use of fluorometholone and combined use of azelastine and fluorometholone are effective in alleviating the signs and symptoms of severe ACD, optimal response can be achieved with adjunctive treatment including azelastine.

Three-Dimensional Choroidal Vascularity Index in High Myopia Using Swept-Source Optical Coherence Tomography

PURPOSE

To characterize the choroidal vasculature in high myopic eyes by three-dimensional choroidal vascularity index (CVI) using swept-source optical coherence tomography (SS-OCT).

SUBJECTS AND METHODS

A cross-sectional observational study of 98 right eyes from 98 consecutive nonpathological myopic patients, including 46 high myopes (HM) and 52 low to moderate myopes (LMM). OCT and OCT angiography covering an area of 6 × 6 mm² centered on the fovea was conducted with a commercially available SS-OCT device. Three-dimensional CVI was defined as the ratio of choroidal vessel volume (CVV) to total choroidal volume. With the built-in automated quantification software, we assessed choroidal vascular and stromal features: three-dimensional CVI; CVV; choriocapillaris flow density and choroidal stroma volume (CSV) apart from choroidal thickness (CT).

RESULTS

Compared to LMM, there was a significant reduction in three-dimensional CVI, CVV and CSV along with choroidal thinning in HM at both subfoveal and macular regions (all P < .01). The nasal quadrant had both the lowest CVI and the thinnest choroid. The greatest CVI was at the subfovea, while the choroid at the subfovea was thinner than that at the superior, temporal, and inferior quadrants. Multiple linear regression indicated that choroidal characteristics (CVI, CVV, CSV, CT) were mainly negatively correlated with axial length (all P < .01) instead of myopic spherical equivalent (all P > .05).

CONCLUSIONS

Besides two-dimensional choroidal thinning, we also found the axial length-related reduction of three-dimensional choroidal vessel and stroma components in high myopic eyes without myopic maculopathy. The quadrantal distribution characteristics of three-dimensional CVI indicate the subfovea and the nasal quadrant to be the essential quadrants for monitoring the choroidal vasculature alteration in the progression of myopia. The novel quantitative analyses of the choroidal vasculature by three-dimensional CVI may help to characterize the underlying pathophysiology of nonpathological high myopia.

The inhibiting effect of Aspirin Triggered-Resolvin D1 in non-canonical pyroptosis in rats with acute keratitis

PURPOSE

To investigate the effect of Aspirin Triggered-Resolvin D1 (AT-RvD1) as an anti-pyroptosis and anti-inflammatory agent on lipopolysaccharide (LPS) induced acute keratitis in Wistar rats.

METHODS

Acute keratitis in rats were induced by LPS stromal injection. Inflammatory reaction was measured by clinical score and histological observations. The non-canonical pyroptosis, the role of AT-RvD1 and Docosahexaenoic Acid (DHA) on non-canonical pyroptosis, were verified by quantification real-time PCR (qRT-PCR) and Western-blot. Besides, Human corneal epithelial cells (HCECs) primed with LPS, were stimulated with Nigericin, AT-RvD1 and necrosulfonamide (NSA), a Gasdermin-D (GSDMD) inhibitor separately. CCK-8 tests and flow cytometry were conducted to evaluate the cell viability and death ratio. And the marker of non-canonical pyroptosis were verified by Western blot.

RESULTS

AT-RvD1 and DHA both alleviated the inflammation of rat cornea through inhibiting the expression of Caspase-11 and p30 which was triggered by LPS. Meanwhile, the activation of Caspase-4 and p30 were also significantly suppressed by AT-RvD1 in vitro, which is consistent with the results in rats.

CONCLUSIONS

The non-canonical pyroptosis signaling pathways played an important role in rats with acute keratitis. In addition, AT-RvD1 can exert as an anti-inflammatory activity by inhibiting the non-canonical pyroptosis. Hence, it may be a promising and safe agent in treating acute keratitis.

Efficacy of combined orthokeratology and 0.01% atropine for myopia control: the study protocol for a randomized, controlled, double-blind, and multicenter trial

BACKGROUND

The prevalence of myopia is increasing worldwide and is presently recognized as a major public health issue. Researchers and clinicians have been devoted in exploring appropriate clinical interventions to slow its progression in children. Mounting publications have proven that both orthokeratology (OK lens) and 0.01% atropine eyedrop can retard eye growth and myopia progression. However, it remains unclear whether the combination of OK lens and 0.01% atropine has the potential to magnify the effectiveness of myopia control. The present study aims to compare the myopia control efficiency of the combination of OK lens and 0.01% atropine with the monotherapy of OK lens in children.

METHODS

The present study is a randomized, controlled, double-blind and multicenter clinical trial. A total of 96 children within 8-12 years old were recruited. These participants are treated with the combination of OK lens and 0.01% atropine eyedrop or the combination of OK lens and placebo eyedrop. Each group includes 48 participants. The inclusion criteria are as follows: myopia between - 1.00 and - 4.00 D in either eye and astigmatism of no more than 1.50 D. The follow-up time points will be 1, 6, 12, 18, and 24 months from randomization. The primary outcome is determined by the difference in axial length of the two groups, between the baseline and 24 months from randomization.

DISCUSSION

The present randomized, controlled clinical trial would indicate the additive effects of the combination of OK lens and 0.01% atropine, and the extent of these effects, in retarding myopia progression and axial elongation in children.

TRIAL REGISTRATION

Chinese Clinical Trial Registry (ChiCTR), ChiCTR1800018419 . Registered on 17 September 2018. http://www.chictr.org.cn/showproj.aspx?proj=29216.

Combination of 0.05% Azelastine and 0.1% Tacrolimus Eye Drops in Children With Vernal Keratoconjunctivitis: A Prospective Study

Aims: To compare the efficacy of the combination of 0. 05% azelastine and 0.1% tacrolimus eye drops with 0.1% tacrolimus monotherapy in pediatric patients with vernal keratoconjunctivitis (VKC).

Methods: Prospective study. Seventy-six patients with VKC were randomized 1:1 into monotherapy group with 0.1% tacrolimus or combination therapy group with 0.1% tacrolimus and 0.05% azelastine. The Ocular Surface Disease Index (OSDI) scores and the signs of conjunctival hyperemia, corneal involvement, and palpebral conjunctiva papillae were assessed at baseline and at 1, 2, and 6 weeks after treatment.

Results: Two groups were comparable in age, sex, duration of VKC, OSDI, and clinical signs of VKC at baseline. Significant improvements in OSDI score and clinical signs were observed in both groups at all follow-up visits (all p < 0.001), compared with baseline. The combination therapy group showed a larger decrease in OSDI score from baseline (10.30 ± 0.9) compared with monotherapy group (7.30 ± 0.7, p =0.0085) at 1 week. Greater improvements in conjunctival hyperemia and conjunctival papillae were identified in the combination therapy group, compared with in the monotherapy group, at all follow-up visits (all p < 0.05). The corneal involvement scores in the combination group is significantly lower than the monotherapy group at 2 weeks after the treatment (p = 0.0488). No severe adverse effect was found in either group during the study.

Conclusions: Compared with a monotherapy of 0.1% tacrolimus, the combination of 0.05% azelastine and 0.1% tacrolimus eye drops lead to faster and greater improvements in clinical signs and symptoms of vernal keratoconjunctivitis in pediatric patients.

Comparative proteome analysis of form-deprivation myopia in sclera with iTRAQ-based quantitative proteomics

Objective

Scleral remodeling plays a key role in axial elongation in myopia. The aim of the present study was to identify the proteomics changes and specific signaling networks to gain insight into the molecular basis of scleral remodeling in myopic eyes.

Methods

Guinea pig form-deprivation myopia was induced with a translucent diffuser on a random eye for 4 weeks, while the other eye served as the contralateral control group. The axial length and refraction were measured at the beginning and end of the treatment. The proteins were extracted from the sclerae of each group and prepared for quantitative isobaric tags for relative and absolute quantification (iTRAQ) labeling combined with liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis. The coexpression networks and protein functions were analyzed using Gene Ontology (GO) and Ingenuity Pathway Analysis (IPA). Quantitative real-time PCR (qRT-PCR) and western blotting were performed to confirm the authenticity and accuracy of the iTRAQ results.

Results

After 4 weeks, the form-deprivation eyes developed significant degrees of myopia, and the axial length increased statistically significantly (p<0.05). A total of 2,579 unique proteins with <1% false discovery rate (FDR) were identified. Furthermore, 56 proteins were found to be upregulated, and 84 proteins were found to be downregulated, with a threshold of a 1.2-fold change and p<0.05 in the myopia group, when compared to the control group. Further bioinformatics analysis indicated that 44 of 140 differentially expressed proteins were involved in cellular movement and cellular assembly and organization. The qRT-PCR or western blotting results confirmed that myosin IIB, ACTIN3, and cellular cytoskeletons were downregulated, while RhoA and RAP1A were upregulated in the sclera in myopic eyes. These results were consistent with the proteomics results.

Conclusions

Proteomics and bioinformatics results can be helpful for identifying proteins and providing new insights for better understanding of the molecular mechanism underlying scleral remodeling. These results revealed that the proteins associated with cellular movement and cellular assembly and organization are altered during the development of myopia. Furthermore, RhoA plays a key role in the pathways involved in cellular movement and cellular assembly and organization.

Transient reduction in the retinal microvascular network following implantation surgery of implantable collamer lens: An OCT angiography study

Purpose

To evaluate changes in the retinal microvascular network after posterior chamber phakic implantable collamer lens (ICL) surgery using optical coherence tomography angiography (OCTA) in patients with high myopia.

Methods

Patients with high myopia who underwent ICL surgery were enrolled in this study. All patients underwent comprehensive ophthalmologic exams preoperatively and 1 week, 1 month, and 3 months postoperatively. The vascular densities (VDs) in the retina and the superficial and deep capillary plexuses of different annular and quadrantal areas were evaluated from OCTA images (Zeiss Cirrus 5000). Correlations between the variations in microvascular density and possible factors were further analyzed.

Results

The study comprised 32 eyes of 32 patients. The mean age of the patients was 26.91±7.610 years (15 men and 17 women). A statistically significant reduction in microvascular density in the retina and the superficial plexus was found 1 week and 1 month postoperatively (p<0.05, repeated-measures ANOVA). Further fractal analysis found that the VD of the outer ring declined statistically significantly (p<0.05). A statistically significant decrease was also found in the inferior nasal sector 1 week postoperatively, with an overall decrease in all four quadrants 1 month postoperatively. The microvascular density recovered toward the baseline level 3 months postoperatively. No correlations were observed between the variation in microvascular density and the spherical equivalent (SE), axial length (AL), intraocular pressure (IOP), amplitude of accommodation (AA), or contrast sensitivity.

Conclusions

Retinal microvascular density was decreased postoperatively and then recovered toward the baseline level after 3 months. ICL surgery may have a transient influence on the retinal microvascular network without affecting visual function.

Alternative Flicker Glass: a New Anti-suppression Approach to the Treatment of Anisometropic Amblyopia

INTRODUCTION

Amlyopia always presents with monocular and binocular dysfunction. In this study, we aim to investage the efficacy of alternative occlusion using liquid crystal glasses versus continuous occlusion therapy using traditional patches for treating amblyopia.

METHODS

Eligible subjects with anisometropic amblyopia were randomized into two groups: alternative flicker glass (AFG) or patching group. In the AFG group, subjects were instructed to wear the flicker glasses for 1 hour a day. The AFG is a lightweight spectacle frame with liquid crystal lenses that provide direct square-wave alternating occlusion, which were pre-programmed at temporal frequency of 7Hz. In the patching group, the patients were prescribed to wear traditional patches for 2 hours a day. The best corrected visual acuity (BCVA), contrast sensitivity function (CSF) and stereoacuity were measured at the baseline, 3 and 12 weeks.

RESULTS

In this pilot study, a total of forty children were recruited, with twenty in the AFG group. Mean BCVA improved by 0.17±0.14logMAR (95% CI=0.10 to 0.23) in the AFG group, while 0.18±0.18logMAR (95% CI=0.09 to 0.26) in the patching group from baseline to 12 weeks. The improvement of BCVA in both groups were significant (both P＜0.01), while no significant difference between the groups (P=0.82). The CSF of both low and high spatial frequencies exhibited significant improvement at 12 weeks in the AFG group (P＜0.01, respectively), while just have a significant improvement at low spatial frequency in the patching group (P＜0.01). The stereoacuity significantly improved by 504.00±848.00 (95% CI= -900.88 to -107.12) arc seconds in the AFG group (P＜0.05), while 263.50± 639.55 (95% CI=-562.82 to 35.82) arc seconds in the patching group (P＞0.05).

CONCLUSION

Alternative flicker glass was effective in improving both monocular and binocular function, which was most likely achieved by reducing the suppression and promoting binocular fusion. This therapy exhibited promise as an alternative method for amblyopia treatment.

Change and Recovery of Choroid Thickness after Short-term Application of 1% Atropine Gel and Its Influencing Factors in 6-7-year-old Children

PURPOSE

To investigate the change and recovery of choroid thickness after short-term application of 1% atropine gel and its influencing factors in 6-7-year-old children.

MATERIALS AND METHODS

71 right eyes of 71 children were enrolled and divided into myopia and control group. 1% atropine gel was administered twice a day for one week and then stopped. Spherical equivalent (SE), accommodative amplitude (AA), keratometry (K), axial length (AL), and choroidal thickness (CT) were obtained at baseline and 1^st, 4^th, and 8^th weeks. CT was measured at subfovea and 1 mm, 2 mm, and 3 mm temporal, superior, nasal, and inferior from the fovea using spectral-domain optical coherence tomography.

RESULTS

In both groups, all CTs increased following the change in SE, AA, and AL after administration of 1% atropine for one week. They gradually recovered to baseline levels seven weeks after withdrawal. The change (Δ) in CT at 3 mm superior from the fovea was significantly higher in the myopia group than in the control group. In both groups, ΔCT at subfovea had no significant correlation with SE, AA, and AL, both at baseline and one week. However, ΔCT at subfovea was negatively correlated with ΔAL in the control group.

CONCLUSIONS

One-week application of 1% atropine gel may increase CT in 6-7-year-old Chinese children. Meanwhile, the recovery process after withdrawal lasts seven weeks. During the recovery process, the changes in structural parameters (AL, CT) and functional parameters (AA, SE) in both groups occurred synchronously. The SE, AA, and AL at baseline may not predict the extent of atropine's effect on CT.

Transient Alteration of Retinal Microvasculature after Refractive Surgery

PURPOSE

The purpose of this study was to determine the retinal microvasculature in myopic patients after refractive surgery.

METHODS

Thirty-six right eyes of 36 patients who undertook femtosecond laser-assisted laser in situ keratomileusis (FS-LASIK) were imaged using optical coherence tomography angiography preoperatively, 1-week, 1-month, and 3-month postoperation, respectively. Vessel density was analyzed after the correction of magnification, and results were correlated with clinical manifestations, including spherical equivalent (SE), amplitude of accommodation, intraocular pressure, and axial length.

RESULTS

There was a significant decrease in microvascular density 1-week postoperation compared to preoperative measurement (p < 0.05), and it recovered 1-month postoperation. Microvascular densities in superficial vascular plexus (r = 0.528, p < 0.01), deep vascular plexus (r = 0.500, p < 0.01), and retinal vascular network (r = 0.390, p < 0.05) were all positively correlated with the decrease of the SE 1-week postoperation.

CONCLUSION

The transient alteration of the retinal microvasculature after refractive surgery appeared to recover quickly, which may not impact the visual function after FS-LASIK.

Rete Ridges in Eyelid Margin and Inflammatory Cytokines in Meibomian Gland Dysfunction Associated with Dry Eye Symptom

PURPOSE

To evaluate the morphology and function of rete ridges in eyelid margin and inflammatory cytokines in meibomian gland dysfunction (MGD) associated with dry eye symptom.

METHODS

A total of 63 subjects with OSDI score ≥13 were enrolled in MGD group and no-MGD group. Main measurements included tear cytokines levels and the rete ridges morphology.

RESULTS

Meibomian gland loss (MGL), corneal staining score (CSS), and IL-6 and TNF-α increased, meibomian gland secretion (MGS) decreased, the density of the rete ridges was lower, the longest diameters and shortest diameters of the rete ridges were longer in MGD group. The MGD group showed a negative correlation between MGL and BUT and MGS, but it showed a positive correlation with CSS. CSS was negatively correlated with IL-6. LLT was negatively correlated with IL-2 and IL-4. The shortest diameters of rete ridges in eyelid margin had a significant positive correlation with IL-2, IL-4, IL-10, and IFN-γ levels.

CONCLUSION

Change of meibomian gland function and the rete ridges morphology might have some correlation with the injury to ocular surface. Some inflammatory cytokines were correlated with the change of the rete ridges morphology, which might in turn affect the ocular surface function.

Myopia-related stepwise and quadrant retinal microvascular alteration and its correlation with axial length

PURPOSE

To investigate the characteristics of retinal vascular alterations in patients with varying degrees of myopia, and to determine correlated variables and alteration patterns over different retinal zones.

METHODS

A total of 208 right eyes of 208 patients with myopia were enrolled and divided into mild, moderate, high, and extreme myopia groups. The macular vasculature in superficial, deep, and whole retinal layers was imaged with optical coherence tomography angiography (OCTA). The vessel densities over the whole annular zone, four quadrants, and six annuli were quantified as fractal dimension using a customized software. Simple linear regressions and ridge regression were used to determine and compare explanatory variables of microvascular density.

RESULTS

The microvascular density within the superficial, deep and whole retinal layers was highest in mild myopia group, second highest in moderate myopia group, second lowest in high myopia group and lowest in extreme myopia group. Within the same layer, differences between any two groups were significant (all p < 0.05). Among the four quadrants, only the inferior nasal (IN) quadrant showed no difference in microvascular density between mild and moderate groups. Ridge regression indicated that microvascular density values in all three layers were more strongly correlated with axial length (AL) (scaled estimates -0.139, -0.103, -0.154; all p < 0.001) than with spherical equivalent (SE) (scaled estimates -0.052, -0.096, -0.057; all p < 0.05).

CONCLUSIONS

We characterized a stepwise and quadrant alteration of retinal microvascular density from mild to extreme myopia, which was more strongly affected by axial elongation, although both AL and SE were meaningful indicators.

Overexpression of UBE2C correlates with poor prognosis in gastric cancer patients

OBJECTIVE

The ubiquitin-conjugating enzyme E2C (UBE2C) has been known as a crucial factor upregulated in various tumors. The functions of UBE2C is mainly involved in the pathway protein ubiquitination. This study investigates the expression of UBE2C in gastric cancers and its correlation with overall survival rate.

MATERIALS AND METHODS

Real-time PCR (RT-PCR) and Western blotting were performed to determine the expression of UBE2C in gastric cancer samples and adjacent normal tissues. Immunohistochemical staining was used to assess the expression of UBE2C in 216 paraffin-embedded gastric cancer tissues.

RESULTS

The mRNA and relevant protein levels of UBE2C in gastric cancer tissues are significantly greater than those in the adjacent normal tissues. Also, the expression of UBE2C is found to correlate with lymphatic metastasis, serosa invasion, TNM (Malignant Tumors) staging and Lauren's classification (p<0.05). The univariate analysis shows that the overexpression of UBE2C associates with poor prognosis (p=0.001). The multivariate analysis demonstrates that expression of UBE2C, lymphatic metastasis, and TNM staging are independent prognostic indicators.

CONCLUSIONS

This study shows that overexpression of UBE2C contributes to the development of gastric cancer, and UBE2C has the potential to be exploited as a therapeutic target.

Microbial Contamination of Rigid Gas Permeable (RGP) Trial Lenses and Lens Cases in China

Purpose: This study aimed to evaluate the microbial contamination level and its influencing factors of rigid gas permeable (RGP) trial lenses and lens cases in China.Materials and Methods: A total of 107 RGP trial lenses and lens cases were collected from 7 main hospitals or optometric centers in China. Three sites including the lenses, case interiors and case screw tops were sampled for bacterial and fungal culture and identification. The contamination rates of these three sites and their relationship with lens care regimes were further analyzed.Results: The overall contamination rate was 73.8% for either lenses or cases, and 43.0% of lenses, 57.0% of case interiors and 65.4% of case screw tops respectively. The most frequently isolated microorganisms were Serratia spp., Burkholderia spp., Pandoraea spp., and Achromobacter spp. from all three sites. The contamination rate was positively related to the lens use frequency. Compared with dry-stored lenses, the contamination rate was significantly higher in wet-stored group (P < .001*). Inadequate disinfection and improper lens and case care regimes were also associated with higher contamination rates.Conclusions: Our study reported that the RGP trial lenses and cases used for fittings had a considerably high contamination rate. The safe use of RGP trial lenses and education of optometrists on the regular maintenance of trial lenses should be emphasized.

Substance P inhibits high urea-induced apoptosis through the AKT/GSK-3β pathway in human corneal epithelial cells

To investigate the effect of substance P (SP) on human corneal epithelial cells (HCECs) that have been stressed by a high urea environment and to determine the relationship between SP and the protein kinase B (AKT)/glycogen synthase kinase-3β (GSK-3β) signaling pathway. An in vitro model of chronic renal failure (CRF)-related dry eye was used to study HCECs that were treated with high urea concentrations. Cell proliferation was assayed using a cell counting kit-8 test. Besides, cell apoptosis was evaluated by flow cytometry. Furthermore, the effects of SP and the AKT inhibitor perifosine on the urea-treated HCECs were examined using immunofluorescence, quantitative real time polymerase chain reaction (qRT-PCR), and Western blot analysis. SP markedly reduced the number of apoptotic HCECs and decreased the cleaved caspase-3 expression levels while contributing to increased cellular proliferation (P < 0.05). The Western blot analysis and qRT-PCR experiments revealed that SP significantly increased the expression of p-AKT and p-GSK-3β (P < 0.05); additionally, these increases were attenuated after the perifosine inhibition of the AKT signaling pathway (P < 0.05). These in vitro experiments demonstrated that SP may protect against the apoptotic damage of HCECs caused by the high urea condition. The underlying mechanism may be related to the activation of the AKT/GSK-3β signaling pathway.

Involvement of ciliary neurotrophic factor in early diabetic retinal neuropathy in streptozotocin-induced diabetic rats

Objective

Ciliary neurotrophic factor (CNTF) has been evaluated as a candidate therapeutic agent for diabetes and its neural complications. However, its role in diabetic retinopathy has not been fully elucidated.

Methods

This is a randomized unblinded animal experiment. Wistar rats with streptozocin (STZ)-induced diabetes were regularly injected with CNTF or vehicle control in their vitreous bodies beginning at 2 weeks after STZ injection. A total of five injections were used. In diabetic rats, the levels of CNTF and neurotrophin-3 (NT-3) were evaluated by enzyme-linked immunosorbent assays (ELISA) and real-time PCR. The abundance of tyrosine hydroxylase (TH) and β-III tubulin was detected by western blot. Transferase-mediated dUTP nick-end labeling staining (TUNEL) was used to detect cell apoptosis in the retinal tissue. The activation of caspase-3 was also measured.

Results

The protein and mRNA levels of CNTF in diabetic rat retinas were reduced compared to control rats. In addition, retinal ganglion cells (RGCs) and dopaminergic amacrine cells appeared to undergo degeneration in diabetic rat retinas, as revealed by transferase-mediated dUTP nick-end labeling staining (TUNEL). Tyrosine hydroxylase (TH) and β-III tubulin protein levels also decreased significantly. Intraocular administration of CNTF rescued RGCs and dopaminergic amacrine cells from neurodegeneration and counteracted the downregulation of β-III tubulin and TH expression, thus demonstrating its therapeutic potential.

Conclusion

Our study suggests that early diabetic retinal neuropathy involves the reduced expression of CNTF and can be ameliorated by an exogenous supply of this neurotrophin.

Effects of Tear Film Lipid Layer Thickness and Blinking Pattern on Tear Film Instability After Corneal Refractive Surgery

PURPOSE

To investigate associations between changes in tear film instability and the lipid layer thickness (LLT) and blink pattern after corneal refractive surgery (CRS).

METHODS

Forty patients were enrolled in this study. The LLT and blink pattern were evaluated 1 week before and 30 days after CRS using a novel interferometer and an ocular surface disease index (OSDI) questionnaire, and other tear film stability markers were also evaluated.

RESULTS

Mean OSDI scores increased from 5.52 to 8.54 (P = 0.016), corneal fluorescence staining scores increased from 0.05 to 0.25 (P = 0.034), first noninvasive tear breakup time (NIBUT-F) decreased from 9.66 to 7.33 seconds (P = 0.014), and average noninvasive tear breakup time (NIBUT-Ave) decreased from 12.32 to 10.26 seconds (P = 0.047) 1 month after CRS. Meanwhile, mean total blink frequency in 20 seconds decreased significantly from 12.62 to 6.31 (P < 0.001); LLT did not change significantly (P = 0.447). The change in NIBUT-Ave was positively correlated with that in LLT (P = 0.003) and negatively correlated with that in the partial blink rate (P = 0.013). The changes in the OSDI questionnaire, NIBUT, LLT, and blink pattern were not different between the laser-assisted in situ keratomileusis and laser-assisted subepithelial keratomileusis groups.

CONCLUSIONS

A decrease in tear film stability occurs 1 month after CRS, the change in the blink pattern and unchanged LLT preoperatively and postoperatively suggesting that these parameters play a role in maintaining tear film stability after CRS.

Overexpression of UBE2C correlates with poor prognosis in gastric cancer patients

OBJECTIVE

The ubiquitin-conjugating enzyme E2C (UBE2C) has been known as a crucial factor upregulated in various tumors. The functions of UBE2C is mainly involved in the pathway protein ubiquitination. This study investigates the expression of UBE2C in gastric cancers and its correlation with overall survival rate.

MATERIALS AND METHODS

Real-time PCR (RT-PCR) and Western blotting were performed to determine the expression of UBE2C in gastric cancer samples and adjacent normal tissues. Immunohistochemical staining was used to assess the expression of UBE2C in 216 paraffin-embedded gastric cancer tissues.

RESULTS

The mRNA and relevant protein levels of UBE2C in gastric cancer tissues are significantly greater than those in the adjacent normal tissues. Also, the expression of UBE2C is found to correlate with lymphatic metastasis, serosa invasion, TNM (Malignant Tumors) staging and Lauren's classification (p<0.05). The univariate analysis shows that the overexpression of UBE2C associates with poor prognosis (p=0.001). The multivariate analysis demonstrates that expression of UBE2C, lymphatic metastasis, and TNM staging are independent prognostic indicators.

CONCLUSIONS

This study shows that overexpression of UBE2C contributes to the development of gastric cancer, and UBE2C has the potential to be exploited as a therapeutic target.

The Relationship Between High-Order Aberration and Anterior Ocular Biometry During Accommodation in Young Healthy Adults

Purpose

This study investigated the anterior ocular anatomic origin of high-order aberration (HOA) components using optical coherence tomography and a Shack-Hartmann wavefront sensor.

Methods

A customized system was built to simultaneously capture images of ocular wavefront aberrations and anterior ocular biometry. Relaxed, 2-diopter (D) and 4-D accommodative states were repeatedly measured in 30 young subjects. Custom software was used to correct optical distortions and measure biometric parameters from the images.

Results

The anterior ocular biometry changed during 2-D accommodation, in which central lens thickness, ciliary muscle thicknesses at 1 mm posterior to the scleral spur (CMT1), and the maximum value of ciliary muscle thickness increased significantly, whereas anterior chamber depth, CMT3, radius of anterior lens surface curvature (RAL), and radius of posterior lens surface curvature (RPL) decreased significantly. 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Conclusions

HOA components altered during step-controlled accommodative stimuli. Ciliary muscle first contracted during stepwise accommodation, which may directly contribute to the reduction of spherical aberration (SA). The lens morphology was then altered, and the change in anterior lens surface curvature was related to the variation of coma.

Crosslinking Enzyme Lysyl Oxidase Modulates Scleral Remodeling in Form-Deprivation Myopia

PURPOSE

Scleral remodeling causes the excessive ocular elongation that underlies myopia. Lysyl oxidase (LOX), a copper-containing amine oxidase, can catalyze collagen and elastin crosslinking. The purpose of this study was to investigate the role of LOX in scleral remodeling in form-deprivation myopia (FDM).

METHODS

Seventy-five guinea pigs were randomly divided into five groups as follows: a normal control group, an FDM group, an FDM plus β-aminopropionitrile (BAPN) group, an FDM plus TGF-β1 (TGF-β1) group, and an FDM plus vehicle group. A translucent diffuser was used to induce FDM, and intravitreal injection was used to administer BAPN, TGF-β1 or vehicle. The scleral LOX and collagen gene and protein levels and the posterior scleral ultrastructure and biomechanics were measured.

RESULTS

In the FDM group, both the scleral LOX and collagen gene and protein levels were significantly lower than those in the control eyes. The collagen fibril diameters were significantly decreased in the FDM group compared with the diameters in the control group. A significant decrease in LOX gene and protein expression was observed after BAPN injection, and an increase was observed after TGF-β1 treatment compared with the levels in the FDM group. Additionally, the scleral collagen fibrils were significantly decreased in the BAPN-treated eyes but increased in the TGF-β1-treated eyes compared with the FDM eyes. The ultimate stress and Young's modulus of the sclera were lowest in the BAPN group, followed by the FDM group and the TGF-β1 group. The ultimate strain (%) of the sclera was lowest in the TGF-β1 group, followed by the FDM group and the BAPN group.

CONCLUSION

LOX expression was significantly lowered in myopic sclera. Modulating LOX expression induced a change in both the scleral collagen fibril diameter and the scleral biomechanics. Therefore, LOX may play a key role in the myopia scleral remodeling procedure.

Effects of caloric restriction on peroxisome proliferator-activated receptors and positive transcription elongation factor b expression in obese rats

OBJECTIVE

To investigate the effect of caloric restriction (CR) on expressions of peroxisome proliferators-activated receptors (PPARs) and positive transcription elongation factor b (P-TEFb) (including cyclin-dependent kinase 9 (CDK9) and cyclin T1) protein in visceral adipose tissue of obese rats.

MATERIALS AND METHODS

Obese rats were induced by high-fat diet for 8 weeks. Then they were divided into three groups: Model (n=5), 50% Calorie Restricted (50% CR, n=5), Intermittent Fasting (IF) (eight cycles of 3-d fasting and 3-d refeeding, n=6) for 8 weeks. Biochemical parameters were measured. Protein and mRNA expression of Cdk9, cyclin T1 and PPARs were qualified in visceral adipose tissue.

RESULTS

A significant decline in fasting plasma glucose (FPG), homeostatic model assessment of insulin resistance (HOMA-IR), body weight, and visceral fat weight was observed in 50% CR group. The IF group exhibited a significant decrease in FPG, HOMA-IR, visceral fat weight. Both 50% CR and IF down-regulated mRNA and protein expression of PPARγ and Cdk9, cyclin T1 and up-regulated mRNA and protein expression of PPARβ.

CONCLUSIONS

These results suggest that the effects of 50% CR and IF on HOMA-IR, body weight, visceral fat weight, P-TEFb and PPARγ expression may be related to their protective potential on obesity.

Retinal Microvascular Network and Microcirculation Assessments in High Myopia

PURPOSE

To investigate the changes of the retinal microvascular network and microcirculation in high myopia.

DESIGN

A cross-sectional, matched, comparative clinical study.

PARTICIPANTS

Twenty eyes of 20 subjects with nonpathological high myopia (28 ± 5 years of age) with a refractive error of -6.31 ± 1.23 D (mean ± SD) and 20 eyes of 20 age- and sex-matched control subjects (30 ± 6 years of age) with a refractive error of -1.40 ± 1.00 D were recruited.

METHODS

Optical coherence tomography angiography (OCTA) was used to image the retinal microvascular network, which was later quantified by fractal analysis (box counting [D_box], representing vessel density) in both superficial and deep vascular plexuses. The Retinal Function Imager was used to image the retinal microvessel blood flow velocity (BFV). The BFV and microvascular density in the myopia group were corrected for ocular magnification using Bennett's formula.

RESULTS

The density of both superficial and deep microvascular plexuses was significantly decreased in the myopia group in comparison to the controls (P < .05). The decrease of the microvessel density of the annular zone (0.6-2.5 mm), measured as D_box, was 2.1% and 2.9% in the superficial and deep vascular plexuses, respectively. Microvessel density reached a plateau from 0.5 mm to 1.25 mm from the fovea in both groups, but that in the myopic group was about 3% lower than the control group. No significant differences were detected between the groups in retinal microvascular BFV in either arterioles or venules (P > .05). Microvascular densities in both superficial (r = -0.45, P = .047) and deep (r = -0.54, P = .01) vascular plexuses were negatively correlated with the axial lengths in the myopic eye. No correlations were observed between BFV and vessel density (P > .05).

CONCLUSIONS

Retinal microvascular decrease was observed in the high myopia subjects, whereas the retinal microvessel BFV remained unchanged. The retinal microvascular network alteration may be attributed to ocular elongation that occurs with the progression of myopia. The novel quantitative analyses of the retinal microvasculature may help to characterize the underlying pathophysiology of myopia and enable early detection and prevention of myopic retinopathy.

Wavefront Derived Refraction and Full Eye Biometry in Pseudophakic Eyes

Purpose

To assess wavefront derived refraction and full eye biometry including ciliary muscle dimension and full eye axial geometry in pseudophakic eyes using spectral domain OCT equipped with a Shack-Hartmann wavefront sensor.

Methods

Twenty-eight adult subjects (32 pseudophakic eyes) having recently undergone cataract surgery were enrolled in this study. A custom system combining two optical coherence tomography systems with a Shack-Hartmann wavefront sensor was constructed to image and monitor changes in whole eye biometry, the ciliary muscle and ocular aberration in the pseudophakic eye. A Badal optical channel and a visual target aligning with the wavefront sensor were incorporated into the system for measuring the wavefront-derived refraction. The imaging acquisition was performed twice. The coefficients of repeatability (CoR) and intraclass correlation coefficient (ICC) were calculated.

Results

Images were acquired and processed successfully in all patients. No significant difference was detected between repeated measurements of ciliary muscle dimension, full-eye biometry or defocus aberration. The CoR of full-eye biometry ranged from 0.36% to 3.04% and the ICC ranged from 0.981 to 0.999. The CoR for ciliary muscle dimensions ranged from 12.2% to 41.6% and the ICC ranged from 0.767 to 0.919. The defocus aberrations of the two measurements were 0.443 ± 0.534 D and 0.447 ± 0.586 D and the ICC was 0.951.

Conclusions

The combined system is capable of measuring full eye biometry and refraction with good repeatability. The system is suitable for future investigation of pseudoaccommodation in the pseudophakic eye.

Therapeutic efficacy of fibroblast growth factor 10 in a rabbit model of dry eye

The aim of the present study was to investigate the therapeutic efficacy of fibroblast growth factor 10 (FGF10) in the promotion of healing, survival and expression of mucin in corneal epithelial cells in a rabbit dry eye model. A total of 12 healthy female New Zealand white rabbits were divided randomly into three groups. The lacrimal glands were injected with saline either alone (normal control group) or with concanavalin A (Con A), with either topical phosphate-buffered saline (PBS; PBS control group) or 25 µg/ml FGF10 (FGF10 treatment group). Lacrimal gland inflammation, tear function, corneal epithelial cell integrity, cell apoptosis and mucin expression were subsequently assessed. Lacrimal gland tissue biopsies were performed in conjunction with histology and electron microscopy observations. Tear meniscus height (TMH) and tear meniscus area (TMA) were measured using Fourier domain-optical coherence tomography. Tear membrane break-up time (TBUT) was also assessed and corneal fluorescein staining was performed. The percentages of apoptotic corneal and conjunctival (Cj) epithelial cells (ECs) were counted using a terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling method. The mRNA expression levels of Muc1 were determined using reverse transcription-quantitative polymerase chain reaction analyses. The TMH and TMA values of the PBS and treatment groups were found to be significantly reduced, compared with those of the normal control group 3 days after Con A injection. However, the TMH and TMA of the FGF10 treatment group were higher, compared with those of the PBS group 3 and 7 days after treatment, respectively. Furthermore, the FGF10 treatment group exhibited prolonged TBUT, reduced corneal fluorescein staining and repaired epithelial cell ultra-structure7 days after treatment. The percentages of apoptotic corneal- and Cj-ECs in the FGF10 treatment group were significantly reduced, compared with those in the PBS group. FGF10 significantly induced the mRNA expression of Muc1 in the corneal epithelial cells, compared with the normal control group, and induced higher mRNA expression levels of Muc1 in the Cj-ECs, compared with the PBS control group. In the present study, the rabbit dry eye model was successfully established 3 days after lacrimal gland Con A injection. FGF10 eye drops increased TMH and TMA, promoted corneal epithelial healing, reduced apoptosis of the corneal- and Cj-ECs and led to increased expression of Muc1.

Wnt signaling in form deprivation myopia of the mice retina

BACKGROUND

The canonical Wnt signaling pathway plays important roles in cellular proliferation and differentiation, axonal outgrowth, cellular maintenance in retinas. Here we test the hypothesis that elements of the Wnt signaling pathway are involved in the regulation of eye growth and prevention of myopia, in the mouse form-deprivation myopia model.

METHODOLOGY/PRINCIPAL FINDINGS

(1) One hundred twenty-five C57BL/6 mice were randomly distributed into form-deprivation myopia and control groups. Form-deprivation myopia (FDM) was induced by suturing the right eyelid, while the control group received no treatment. After 1, 2, and 4 weeks of treatment, eyes were assessed in vivo by cycloplegic retinoscopic refraction and axial length measurement by photography or A-scan ultrasonography. Levels of retinal Wnt2b, Fzd5 and β-catenin mRNA and protein were evaluated using RT-PCR and western blotting, respectively. (2) Another 96 mice were divided into three groups: control, drugs-only, and drugs+FDM (by diffuser). Experimentally treated eyes in the last two groups received intravitreal injections of vehicle or the proteins, DKK-1 (Wnt-pathway antagonist) or Norrin (Wnt-pathway agonist), once every three days, for 4 injections total. Axial length and retinoscopic refraction were measured on the 14th day of form deprivation. Following form-deprivation for 1, 2, and 4 weeks, FDM eyes had a relatively myopic refractive error, compared with contralateral eyes. There were no significant differences in refractive error between right and left eye in control group. The amounts of Wnt2b, Fzd5 and β-catenin mRNA and protein were significantly greater in form-deprived myopia eyes than in control eyes.DKK-1 (antagonist) reduced the myopic shift in refractive error and increase in axial elongation, whereas Norrin had the opposite effect in FDM eyes.

CONCLUSIONS/SIGNIFICANCE

Our studies provide the first evidence that the Wnt2b signaling pathway may play a role in the development and progression of form-deprivation myopia, in a mammalian model.

Macular pigment optical density and its relationship with refractive status and foveal thickness in Chinese school-aged children

PURPOSE

To investigate macular pigment optical density (MPOD) and its relationship with refractive status and foveal thickness in Chinese school-aged children.

METHODS

Ninety-four healthy Chinese children, 6 to 12 years old, were recruited to the study. MPOD was measured with a heterochromatic flicker photometer (HFP), and foveal thickness, including both minimum and central foveal thicknesses (MFT and CFT, respectively), were measured by optical coherence tomography (OCT) with fast macular map scan. A noncontact tonometer was used to measure intraocular pressure (IOP) followed by determination of the refraction using an autorefractor after cycloplegia. Information on body mass index (BMI) was obtained. The correlation between MPOD values and foveal thickness, spherical equivalent (SE) refraction, IOP, BMI, sex, and age was statistically analyzed using SAS 8.2 statistical software.

RESULTS

The MPOD in examined school-aged children was 0.56 ± 0.25, without any significant difference between boys and girls (p = 0.12). MPOD showed no significant association with age, BMI, IOP, SE, MFT, or CFT. In the myopia group, however, there was an inverse relationship between MPOD and MFT (R =-0.66, p = 0.028) and a positive relationship between MPOD and CFT (R = 0.67, p = 0.025).

CONCLUSIONS

MPOD was inversely related to MFT and positively related to CFT in Chinese school-age children with low-to-moderate myopia. MPOD showed no significant association with age, BMI, IOP, SE or foveal thickness.

Disruption of Type-I IFN pathway ameliorates preservation damage in mouse orthotopic liver transplantation via HO-1 dependent mechanism

Ischemia/reperfusion injury (IRI) remains unresolved problem in clinical organ transplantation. We analyzed the role of Type-I interferon (IFN) pathway in a clinically relevant murine model of extended hepatic cold preservation followed by orthotopic liver transplantation (OLT). Livers from Type-I IFN receptor (IFNAR) knockout (KO) or wild-type (WT) mice (C57/BL6) were harvested, preserved at 4°C in UW solution for 20 h and transplanted to groups of syngeneic IFNAR KO or WT recipients. Liver graft but not recipient IFNAR deficiency was required to consistently ameliorate IRI in OLTs. Indeed, disruption of Type-I IFN signaling decreased serum alanine aminotransferase (sALT) levels (p < 0.001), diminished Suzuki's score of histological OLT damage (p < 0.01) and improved 14-day survival (from 42%[5/12] in WT to 92%[11/12] in IFNAR KO; p < 0.05). Unlike in WT group, IFNAR deficiency attenuated OLT expression of TNF-α, IL-1β, IL-6, MCP-1, CXCL-10, ICAM-1; diminished infiltration by macrophages/PMNs; and enhanced expression of antioxidant HO-1/Nrf2. The frequency of TUNEL+ apoptotic cells and caspase-3 activity/expression selectively decreased in IFNAR KO group. Small interfering (si)RNA-directed targeting of HO-1 restored cardinal features of liver IRI in otherwise resistant IFNAR-deficient OLTs. Thus, intact Type-I IFN signaling is required for hepatic IRI, whereas HO-1 is needed for cytoprotection against innate immunity-dominated organ preservation damage in IFNAR-deficient liver transplants.

Sotrastaurin, a protein kinase C inhibitor, ameliorates ischemia and reperfusion injury in rat orthotopic liver transplantation

Sotraustaurin (STN), a small molecule, targeted protein kinase C (PKC) inhibitor that prevents T-lymphocyte activation via a calcineurin-independent pathway, is currently being tested in Phase II renal and liver transplantation clinical trials. We have documented the key role of activated T cells in the inflammation cascade leading to liver ischemia/reperfusion injury (IRI). This study explores putative cytoprotective functions of STN in a clinically relevant rat model of hepatic cold ischemia followed by orthotopic liver transplantation (OLT). Livers from Sprague-Dawley rats were stored for 30 h at 4°C in UW solution, and then transplanted to syngeneic recipients. STN treatment of liver donors/recipients or recipients only prolonged OLT survival to >90% (vs. 40% in controls), decreased hepatocellular damage and improved histological features of IRI. STN treatment decreased activation of T cells, and diminished macrophage/neutrophil accumulation in OLTs. These beneficial effects were accompanied by diminished apoptosis, NF-κB/ERK signaling, depressed proapoptotic cleaved caspase-3, yet upregulated antiapoptotic Bcl-2/Bcl-xl and hepatic cell proliferation. In vitro, STN decreased PKCθ/IκBα activation and IL-2/IFN-γ production in ConA-stimulated spleen T cells, and diminished TNF-α/IL-1β in macrophage-T cell cocultures. This study documents positive effects of STN on liver IRI in OLT rat model that may translate as an additional benefit of STN in clinical liver transplantation.

Fibroblast growth factor 10 upregulates the expression of mucins in rat conjunctival epithelial cells

PURPOSE

This in vitro study aimed to gain insight into the function of fibroblast growth factor 10 (FGF10) on the ocular surface, especially its effect on mRNA expression of the mucins Muc1, Muc4, and Muc5ac, and mucin protein synthesis.

METHODS

We isolated primary cultured rat conjunctival epithelial cells (Cj-ECs) and treated them with FGF10 (1 ng/ml, 10 ng/ml, 100 ng/ml, and 200 ng/ml) and basic fibroblast growth factor 2 (FGF2; 10 ng/ml) for 24 h or 48 h. The proliferation of Cj-ECs was evaluated by 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS). mRNA levels of Muc1, Muc4, and Muc5ac were determined by real-time PCR. Synthesis levels of MUC1 and MUC4 were measured by western blot. Flow cytometry and Annexin V/PI double staining revealed degrees of apoptosis.

RESULTS

In primary culture, the epithelial cells were compact and cobblestone pavement in shape. Most of the cells were positive for cytokeratin (CK). FGF10 and FGF2 significantly stimulated Muc1, Muc4, and Muc5ac mRNA expression, cell proliferation, and synthesis of MUC1 and MUC4 proteins. FGF10 was more potent than FGF2 in these regards. FGF10 did not restrain the apoptosis of Cj-ECs.

CONCLUSIONS

The results of this study demonstrated that FGF10 is associated with the promotion of Cj-EC proliferation and mucin production. The effects of FGF10 on Cj-ECs support a rationale to investigate its therapeutic potential for ocular surface diseases.

Macular measurements using optical coherence tomography in healthy Chinese school age children

PURPOSE

To evaluate macular thickness/volume in a Chinese population of primary school children using optical coherence tomography (OCT), and assess its association with age, sex, spherical equivalent refraction (SE), body mass index (BMI), and intraocular pressure (IOP).

METHODS

Healthy Chinese children (n = 806) from six randomly selected primary schools in Chongming County, Shanghai, China, were enrolled. Comprehensive standardized ophthalmic examinations included visual acuity, cycloplegic refraction, IOP, and fast macular scans using Stratus OCT. Mean values for the nine Early Treatment Diabetic Retinopathy Study (ETDRS) areas, foveal minimum thickness, and macular volume were calculated.

RESULTS

OCT data from right eyes with high-quality scans were evaluated in 720 children (89.3% of total participants; 46.5% boys). Macular thickness and volume were normally distributed. The mean foveal minimum thickness was 140.0 ± 12.3 μm. There were significant differences between the boys and the girls in mean foveal volume (P = 0.023) and sectoral macular thickness in all the quadrants of the inner ring (P < 0.001 and P = 0.001) and temporal outer quadrant (P = 0.009). SE refraction correlated positively with inner and outer macular thickness and total macular volume (P < 0.001) and negatively with central macular volume (P = 0.012). BMI correlated significantly only with outer macular thickness (r = 0.074, P = 0.048). No age- and IOP-related differences were found in the macular parameters.

CONCLUSIONS

OCT demonstrated that macular thickness/volume was normally distributed in this sample of Chinese children, with variations in sex and SE. The variables in macular thickness/volume should be considered when diagnosing and monitoring school-aged children with diseases that affect the macula.

Improvement of retinal vascular injury in diabetic rats by statins is associated with the inhibition of mitochondrial reactive oxygen species pathway mediated by peroxisome proliferator-activated receptor gamma coactivator 1alpha

OBJECTIVE

Mitochondrial reactive oxygen species (ROS) plays a key role in diabetic retinopathy (DR) pathogenesis. However, whether simvastatin decreases diabetes-induced mitochondrial ROS production remains uncertain. The aim of this study was to clarify the beneficial effects and mechanism of action of simvastatin against diabetes-induced retinal vascular damage.

RESEARCH DESIGN AND METHODS

Diabetic rats and control animals were randomly assigned to receive simvastatin or vehicle for 24 weeks, and bovine retinal capillary endothelial cells (BRECs) were incubated with normal or high glucose with or without simvastatin. Vascular endothelial growth factor (VEGF) and peroxisome proliferator-activated receptor gamma coactivator 1alpha (PGC-1alpha) in the rat retinas or BRECs were examined by Western blotting and real-time RT-PCR, and poly (ADP-ribose) polymerase (PARP), and p38 MAPK were examined by Western blotting. Mitochondrial membrane potential (Deltapsim) and ROS production were assayed using the potentiometric dye 5,5',6,6'- Tetrachloro1,1',3,3'-tetraethyl-benzimidazolylcarbocyanine iodide (JC-1) or CM-H(2)DCFDA fluorescent probes.

RESULTS

Simvastatin significantly upregulated PGC-1alpha (P < 0.01), subsequently decreased Deltapsim (P < 0.05) and ROS generation (P < 0.01), inhibited PARP activation (P < 0.01), and further reduced VEGF expression (P < 0.01) and p38 MAPK activity (P < 0.01). Those changes were associated with the decrease of retinal vascular permeability, retinal capillary cells apoptosis, and formation of acellular capillaries.

CONCLUSIONS

Simvastatin decreases diabetes-induced mitochondrial ROS production and exerts protective effects against early retinal vascular damage in diabetic rats in association with the inhibition of mitochondrial ROS/PARP pathway mediated by PGC-1alpha. The understanding of the mechanisms of action of statins has important implications in the prevention and treatment of mitochondrial oxidative stress-related illness such as DR.

Interaction between the intermediary electron acceptor (pheophytin) and a possible plastoquinone-iron complex in photosystem II reaction centers

Photoreduction of the intermediary electron acceptor, pheophytin (Pheo), in photosystem II reaction centers of spinach chloroplasts or subchloroplast particles (TSF-II and TSF-IIa) at 220 K and redox potential E(h) = -450 mV produces an EPR doublet centered at g = 2.00 with a splitting of 52 G at 7 K in addition to a narrow signal attributed to Pheo([unk]) (g = 2.0033, DeltaH approximately 13 G). The doublet is eliminated after extraction of lyophilized TSF-II with hexane containing 0.13-0.16% methanol but is restored by reconstitution with plastoquinone A (alone or with beta-carotene) although not with vitamin K(1). TSF-II and TSF-IIa are found to contain approximately 2 nonheme Fe atoms per reaction center. Incubation with 0.55 M LiClO(4) plus 2.5 mM o-phenanthroline (but not with 0.55 M LiClO(4) alone) decreases this value to approximately 0.6 and completely eliminates the EPR doublet, but photoreduction of Pheo is not significantly affected. Partial restoration of the doublet (about 25%) was achieved by subsequent incubation with 0.2 mM Fe(2+), but not with either Mn(2+) or Mg(2+). The Fe removal results in the development of a photoinduced EPR signal (g = 2.0044 +/- 0.0003, DeltaH = 9.2 +/- 0.5 G) at E(h) = 50 mV, which is not observed after extraction with 0.16% methanol in hexane. It is ascribed to plastosemiquinone no longer coupled to Fe in photosystem II reaction centers. The results show that a complex of plastoquinone and Fe can act as the stable "primary" electron acceptor in photosystem II reaction centers and that the interaction of its singly reduced form with the reduced intermediary acceptor, Pheo([unk]), is responsible for the EPR doublet.

Redox titration of fluorescence yield of photosystem II

The variable fluorescence yield of photosystem II is dependent on the redox state of the fluorescence quencher molecule or the primary electron acceptor of the system. We have carried out redox titrations of fluorescence yield of a photochemically active photosystem-II reaction-center particle and have measured the redox potential of the photosystem-II primary acceptor.During reductive titrations using dithionite as the reductant, only a single quenching transition was observed. For instance, at pH 7.0, the midpoint potential of the fluorescence transition is -325 mV, and those at a pH between 6.0 and 7.5 are consistent with a pH dependence of about 60 mV/pH unit. At a given pH, the midpoint potential of the transition closely corresponds to that of the most negative transition previously measured in unfractionated chloroplasts (both by chemical reductive titration). Oxidative titrations using ferricyanide as the oxidant yielded hysteresis in the titration curves.Similar changes in fluorescence yield were observed in redox titrations by electrochemical reduction or oxidation. Electrochemical reductive and oxidative titrations yielded reversible transitions, contrary to the hysteresis observed during chemical oxidative titration. From coulometric-titration data, we have estimated that most likely one electron is involved in the redox transition of the fluorescence-quencher or primary-electron-acceptor molecule of photosystem II. These findings are consistent with the current proposal that a membrane-bound plastoquinone functions as the primary acceptor of photosystem II.

Spectral and kinetic evidence for two early electron acceptors in photosystem I

Triton-fractionated photosystem-I particles poised at -625 mV, where the two bound iron-sulfur proteins are reduced, have been studied by optical and electron paramagnetic resonance spectroscopies from 293 to 5 K. At 5-9 K, these particles exhibit two decay components with lifetimes of 1.3 and 130 msec in the laser pulse-induced absorption and electron paramagnetic resonance signal changes. Spectral properties of the 130-msec decay component reflect the charge separation between P-700 and some iron-sulfur center having a broad optical absorbance in the 400- to 550-nm region and a previously reported electron paramagnetic resonance signal with g = 1.78, 1.88, and 2.08. Spectral properties of the 1-msec decay component indicate photoinduced charge separation between P-700 and a chlorophyll a dimer having absorption bands at 420, 450, and 700 nm. It is assumed that these two acceptors participate in the electron transfer from P-700(*) to the bound iron-sulfur proteins.

Oxidation-reduction potentials of bound iron-sulfur proteins of photosystem I

Digitonin - fractionated photosystem - I subchloroplasts were titrated potentiometrically between -450 and -610 mV at pH 10. Examination of the titrated subchloroplasts by low-temperature (13 degrees K) electron paramagnetic resonance spectroscopy revealed resonances centered at values of 2.05, 1.94, 1.92, 1.89, and 1.86 on the g-factor scale. The peak heights depended on the potentials at which the chloroplasts were poised. The resonances of at least three iron-sulfur centers can be recognized: one with lines at g = 2.05 and 1.94; one with lines at g = 2.05, 1.92, and 1.89; and one for which only a line at g = 1.86 has been resolved. The midpoint potentials of the iron-sulfur species fall into two distinctly separate regions: the titration profile of the g = 1.94 signal, the first segment of the g = 2.05 plot, and the rise phase of the g = 1.86 signal had a value of -530 +/- 5 mV; the upper segment of the g = 2.05 plot, the decrease phase of the g = 1.86 signal, and the g = 1.89 profile had a midpoint potential estimated to be [unk] -580 mV. The oxidation-reduction reaction of each of the bound iron-sulfur species, as represented by the changes of the electron paramagnetic resonance spectra, was reversible and apparently involved a two-electron change.Titration at pH 9 could only be carried to -560 mV, and essentially only the first half of the titration behavior as found at pH 10 was seen. At any given potential more positive than -560 mV, the part of the iron-sulfur protein that was not reduced electrochemically could be reduced photochemically, but only to the maximum extent reduced electrochemically at -560 mV. Whereas, chloroplasts illuminated at room temperature and then frozen while still being illuminated developed a signal similar to that produced by electrochemical reduction at -610 mV, illumination at 77 degrees K did not bring about photoreduction beyond that accomplished electrochemically at about -560 mV.Dithionite alone in the dark and under anaerobic conditions brought about a partial reduction to the extent of the first electrochemical reduction step. Dithionite plus illumination at room temperature or dithionite plus methyl viologen in the dark produced the maximum signal. Electron paramagnetic resonance spectra due to either light or electrochemically reduced iron-sulfur proteins showed no detectable decay for at least 3 days when samples were stored in the dark at 77 degrees K.