Corneal Endothelial Cells Research Articles

Factors Affecting the Density of Corneal Endothelial Cells Cultured from Donor Corneas

We investigated which specific correlation exists between the endothelial cell density (ECD) of corneal endothelial cell (CEC) cultures and the features of the donor corneas from which they originate. CEC cultures were prepared from one donor cornea or by pooling together cells of more corneas from elderly donors with ECDs lower or higher than 2000 cells/mm2. The ECDs of such primary cultures were evaluated and showed that that ECDs > 2000 cells/mm2 can be obtained only when CECs are isolated from (1) corneas of young donors; (2) at least two elderly donor corneas (if ECD > 2000 cells/mm2), or three elderly donor corneas (if ECD < 2000 cells/mm2). Secondary cultures are all characterized by ECDs < 2000 cells/mm2. Our study highlights the difficulties in obtaining cultures with ECDs > 2000 cells/mm2. Even if achievable with corneas from young donors, this becomes a challenging task when corneas from elderly donors are used (i.e., the overall majority of those collected by eye banks) and particularly when corneas from elderly donors with ECD < 2000 cells/mm2 are used. Pooling more of two corneas to obtain suitable CECs could technically overcome the problem. The above issues should be tackled appropriately before moving into clinical studies.

Comparative Analysis of Central Corneal Thickness in Ocular Hypertension and Healthy Individuals.

This study aimed to compare the central corneal thickness (CCT) between patients with ocular hypertension (OHT) and healthy individuals, and to investigate the relationship between CCT and intraocular pressure (IOP), diopter, and corneal endothelium cell count (CECC). The CCT of 30 healthy subjects and 38 patients with OHT was measured using a non-contact specular microscope. IOP, diopter, and CECC were also assessed for all participants. Comparative analysis of CCT between the two groups was performed, along with correlation analysis between CCT and each parameter. The average CCT for all participants was 527.57 ± 35.84 µm. The average CCT was 516.07 ± 34.76 µm for healthy subjects and 536.66 ± 34.46 µm for patients with ocular hypertension, showing a significant difference between the two groups (P ≤ 0.05). CCT was not correlated with age (Pearson r = -0.098, P = 0.426), diopter (spherical equivalent refraction) (Pearson r = -0.158, P = 0.197), or corneal endothelium cell count (Pearson r = 0.065, P = 0.598). However, a positive correlation was found between ocular hypertension and central corneal thickness (Pearson r = 0.278, P = 0.022). Patients with ocular hypertension of members of the Chinese Han population exhibited greater CCT compared to healthy subjects in this study. CCT showed no association with age, diopter, or corneal endothelium cell count; however, a positive correlation was observed between intraocular pressure and CCT. With CCT as the abscissa and IOP as the ordinate, the linear regression equation is Y=0.05+0.021X (F = 5.508, P = 0.022). The use of non-contact tonometers for measuring CCT may impact the accuracy of diagnosing and treating glaucoma and ocular hypertension.

Removal of Metallic Foreign Bodies with Complete Penetration of the Cornea: Introduction of a New Approach.

The purpose of this study was to present a new ab interno approach and relevant case series using a polymer-tipped cannula for the removal of metallic foreign bodies that penetrate the full thickness of the cornea and are located in the posterior corneal region. Corneal foreign bodies located on the posterior side of the cornea were gently pushed toward the epithelial side with a polymer-tipped cannula placed using a side-port incision, to be removed without damaging the corneal endothelial layer. The polymer-tipped cannula is specially angled to keep it at a distance from the corneal endothelial layer. In this way, unnecessary endothelial contact and the risk of possible endothelial loss are minimized. The foreign body was held by the epithelium with forceps and carefully removed along the corneal perforation line. This technique was performed in 5 eyes of 5 patients. The mean patient age at the time of surgery was 38.0 ± 12.1 years (range, 28-59 years). Anterior segment optical coherence tomography showed a metallic foreign body and its shadow that completely penetrated the cornea with the deterioration of the endothelial layer in all cases. In all cases, the corneal foreign body was successfully removed. While preoperative corneal endothelial cell density was 3040.0 ± 512.8 cells/mm2, postoperative corneal endothelial cell density was 2927.2 ± 608.1 cells/mm2 at the third postoperative month, and there was no significant corneal endothelial cell loss in any of the cases (P = 0.31). The ab interno approach, performed with a polymer-tipped cannula for the removal of corneal foreign bodies that penetrate deeply, stands out as an important surgical method. This method offers a reliable and effective solution by preventing the foreign body from falling into the anterior chamber and minimizing endothelial damage.

The Role of Mesenchymal Stem Cells for Corneal Endothelial Regeneration: A Systematic Review.

A single layer of tightly spaced cells, known as the endothelium, rests on the posterior side of the cornea. This endothelium regulates the stroma's relative dehydration, which is essential for corneal clarity. Cell therapy is an innovative method being used to repair various corneal abnormalities. Mesenchymal stem cells (MSCs) are now one of the most significant types of stem cells scientists have studied. This study aimed to evaluate the role of MSCs for corneal endothelial regeneration. A systematic review was performed by searching for articles from reputable databases with many study-type references, including PubMed, Cochrane Library, Science Direct, and Google Scholar, up to January 2024. The resulting data were displayed using the 2020 PRISMA flowchart and evaluated using the PRISMA 2020 checklist. Most of the included studies were in vivo and used topical application and anterior chamber injection as the administration routes. Based on the findings of this review, MSCs increased corneal endothelial cell density, improved the defect area and corneal transparency, facilitated endothelial cell regeneration and wound healing, and decreased neovascularization and corneal pro-inflammatory cytokines as compared to controls. Administration of MSCs into the anterior chamber could increase regeneration and proliferation of corneal endothelial tissue.

Effect of preservation on changes in the volume of corneal endothelial cells in an environment with a high concentration of potassium

The experimental study of preservation length on the effect of high potassium concentration in the medium on the volume of human corneal endothelial cells was done. The results of the study of individual samples of fragments of donor material and the values calculated using joined data after hypothermic preservation for 4 and 10 days are presented. The increase of the time when cornea samples are kept in preservation medium (Eusol-C) at 4℃ led to a decrease in the average value (M ± SEM) of cell swelling indicator (N) in a potassium medium from 1.055 ±0.001; n = 982 to 1.014±0.001; n = 338; after 4 and 10 days, respectively. Student’s-t test for independent samples showed a high degree of significance for the difference between these values (p = 2E-76). Identification of the proportion of cells capable to swell in a medium with a high content of potassium ions (N 1), reflecting the electrogenic activity in these cells, showed a decrease of this indicator in the studied groups with increasing duration of preservation (94.3% and 56.8% after 4 and 10 days, respectively). Based on the results of the study, it is suggested that the values of endothelial cells swelling in a potassium environment can serve as indicators of the cells’ ability to restore electrogenic transport. It is concluded that the study of cell swelling in a medium with a high content of potassium ions can provide information for predicting the functionality of the graft.

Computational approaches for identifications of altered ion channels in keratoconus.

Keratoconus is an etiologically complex, degenerative corneal disease that eventually leads to loss of corneal integrity. Cells in corneal epithelium and endothelium express various types of ion channels that play important roles in ocular pathology. This emphasizes the need of understanding alterations of ion channels in keratoconus. Differential gene expression analysis was performed to identify deregulated ion channels in keratoconus patients using transcriptomic data. Thereafter correlation analysis of ion channel expression was performed to obtain the changed correlation between ion channels' expression in keratoconus patients versus control samples. Moreover, Protein-protein interaction networks and a pathway map was constructed to identify cellular processes altered due to the deregulation of ion channels. Furthermore, drugs interacting with deregulated ion channels were identified. Total 75 ion channels were found to be deregulated in keratoconus, of which 12 were upregulated and 63 were downregulated. Correlations between ion channel expressions found to be different in control and keratoconus samples. Thereafter, protein-protein interactions network was generated to identify hub ion channels in network. Furthermore, the pathway map was constructed to depict calcium signalling, MAPK signalling, synthesis and secretion of cortisol, and cAMP signalling. The 19 FDA- approved drugs that interact with the 6 deregulated ion channels were identified. Down-regulation of voltage-gated calcium channels can be attributed to reduced cell proliferation and differentiation. Additionally, deregulated ion channels in 3',5'- cyclic adenosine monophosphate signalling may be responsible for elevated cortisol level in progressive keratoconus patients.

Corneal Endothelial Changes in Chinese Patients with Fuchs’ Uveitis Syndrome

ABSTRACT Purpose To analyze the changes of corneal endothelial cells in Chinese patients with unilateral Fuchs’ uveitis syndrome (FUS) and investigate the factors relevant to these changes. Methods Bilateral specular microscopic examination was performed in 459 Chinese patients with unilateral FUS from April 2008 to April 2023. The affected eyes constituted the study group, while the contralateral eyes served as controls. Results The median values of endothelial cell density (ECD), cell count, total cell size, and hexagonality were significantly lower in the FUS eyes compared to the control eyes (p < 0.001). The median values of average cell size, maximum cell size, SD of cell size, and CV were significantly higher in the FUS eyes compared to the control eyes (p < 0.001). Central ECD showed a negative correlation with age (r = −0.339; p < 0.001), maximum IOP (r = −0.127; p = 0.006), and the interval since symptom onset (r = −0.172; p < 0.001). The ECD was lower in eyes with ocular hypertension compared to those without ocular hypertension (p < 0.001). Eyes with KPs distributed on the central corneal endothelium had a significantly lower ECD than those with KPs distributed diffusely or KPs distributed triangularly on the inferior corneal endothelium (p = 0.006). Conclusion Our findings suggest decreased ECD, increased cell size, and morphological alterations in the affected eyes of Chinese patients with FUS. The reduction in ECD is correlated with age, elevated IOP, the interval since symptom onset, and the distribution of KPs.

Cornea endothelial cell loss before and after explantation of Artisan and Artiflex iris-fixated phakic intraocular lenses

PurposeTo investigate the risk factors for corneal endothelial cell density (ECD) loss of two types of iris-fixated phakic intraocular lenses (pIOL) and indicate the cutoff values for preventing irreversible ECD loss after explantation. DesignThe retrospective, comparative, clinical cohort study MethodsTotal 114 eyes of 61 patients were included in this study. Fifty-five eyes with Artisan pIOL and 59 eyes with Artiflex pIOL had undergone explantation of pIOLs due to continuous ECD loss. Correlation analysis was performed to assess the ocular parameters associated with ECD loss. Receiver operating characteristic (ROC) curve was performed to set cutoff values of ocular parameters to prevent ECD loss after explantation. ResultThe mean ECD before explantation was 1637 cells/mm2 in Artisan group and 1769 cells/mm2 in Artiflex group. The distance of cornea endothelium to IOL center and edges were all significantly higher in Artisan group (p <0.05). The risk factor of decreased ECD in Artisan group were small anterior chamber angle (ACA), and distance of nasal edge of IOL to endothelium and iris fixation to nasal limbus distance, and differences of fixation length. In Artiflex group, ACA, distance of nasal edge of IOL to endothelium, both limbus to IOL fixation length, fixation length, iris pigmentation grading were the risk factors. At 1 year after the pIOL removal, the population demonstrating ΔECD >10% were significantly higher in Artisan group than Artiflex group (p <0.05). In ROC curve analysis, the cutoff value of preoperative ECD to prevent significant post-explantation ECD loss was 1683.5 cells/mm2 in Artisan group and 1648 cells/mm2 in Artiflex group. ConclusionThis study examined the existing explantation guidelines for these lenses. In analyzing the longterm prognosis of cornea ECD with Iris-fixated phakic intraocular lens, it is important to identify the relevant anatomical factors. Small ACA, and short distances from IOL to endothelium and from limbus to iris fixation especially in the nasaSSSl region were significant risk factors to continuous ECD loss in both lenses. To minimize irreversible ECD loss after explantation, it is important to determine the optimal period of explantation by observing both ECD and structural changes.

Successful corneal endothelium preservation in the management of epithelial downgrowth with 5-fluorouracil injections and membranectomy

A 74-year-old Chinese man underwent extracapsular cataract extraction in his right eye and developed a translucent iris membrane 4 months later. He was treated with two intracameral 5-FU injections and membranectomy at 2 weeks apart. At one year following the second membranectomy, the patient maintained a clear cornea without residual or recurrent membrane, an endothelial cell density of 1072 cell/mm2, a visual acuity of 20/50 and a normal intraocular pressure. Our technique of using dispersive and cohesive viscoelastics in protecting the corneal endothelium from intracameral 5-FU, helped preserve corneal endothelial cells and maintain corneal clarity at one year after surgery.

Comparison of treatment outcomes between slow coagulation transscleral cyclophotocoagulation and micropulse transscleral laser treatment

This study compared treatment outcomes of slow coagulation transscleral cyclophotocoagulation (SC-CPC, 65 eyes) and micropulse transscleral laser treatment (MPL, 134 eyes) in patients with medically uncontrolled glaucoma. Success was defined as achieving an intraocular pressure (IOP) of 6–21 mmHg with a ≥ 20% reduction from baseline, no reoperation for glaucoma, and no loss of light-perception vision. Visual acuity, number of glaucoma medication, corneal endothelial cell count, aqueous flare values, and complications were analyzed. At 12 months, mean IOP decreased from 32.2 ± 13.4 to 17.9 ± 8.3 mmHg in the SC-CPC group and from 26.4 ± 10.8 to 16.5 ± 6.8 mmHg in the MPL group. No significant changes were observed in visual acuity, medication count, or corneal endothelial cell count. Aqueous flare values increased immediately after the procedure and gradually decreased in both groups, with greater changes at 1 week significantly associated with greater IOP reduction (p < 0.05). Pupillary abnormalities were found in 5 eyes (4.5%) of the MPL group, with no severe complications. The 12-month success rates were 50.1% for SC-CPC and 38.2% for MPL (p = 0.131). Both SC-CPC and MPL effectively controlled IOP, with early postoperative aqueous flare values predicting treatment outcomes.

Corneal Clarity after Phacoemulsification: Nuclear Management by Stop and Chop vs Divide and Conquer Methods

Background: Restoration of effective vision is the principal aim of all modalities of cataract surgery including Phacoemulsification. Energy level of ultrasonic power in Phacoemulsification and turbulence of fluid in the anterior chamber plays an important role in corneal endothelial cell loss influencing post-operative corneal clarity. Objectives: To compare post-operative corneal clarity after Phacoemulsification by two techniques of nuclear divisions: stop and chop with divide and conquer. Methodology: This prospective observational study was conducted at Shaheed Monsur Ali Medical College and Hospital, Uttara, Dhaka from January, 2023 to June, 2023. The study was carried out on 30 outdoor patients undergoing Phacoemulsification at SMAMCH and Mirpur Eye Hospital, Dhaka. The selected patients underwent detailed ocular and systemic examinations with relevant investigations and divided equally into two groups comprising of 15 in group A (stop and chop) and 15 in group B (divide and conquer). Phacoemulsification was done in all patients by a single expert surgeon. Patients were followed up after 1 week, 4 weeks and 12 weeks of surgery. Corneal endothelial cell count and central corneal thickness were assessed in each visit. Mean value of these mentioned parameters in follow-up periods were compared between two groups. Unpaired t test was done to assess the level of significance. Results: The mean age + standard deviation (SD) of the study subjects was 61.5+2 years, out of which 13(43.33%) were males and other 17(56.67%) females. Pre-operative value of mean endothelial cell count was 2620+70.20/mm2 in group A and 2625+71.10/mm2 in group B. Postoperative mean value + SD of endothelial cell count was 2420+68.90/mm2, 2345+66.64/mm2, 2310+66.04/mm2 respectively after 1 week, 4 weeks and 12 weeks of surgery in group A and 2410+69.54/mm2, 2340 +6587/mm2, 2310+64.45/mm2 in group B respectively. Mean value + SD of central corneal thickness was 545+40.50 micrometer, 535+40.02 micrometer and 532+39.85 micrometer respectively after 1 week, 4 weeks and 12 weeks after surgery in group A and 547+43.98 micrometer, 537+41.23 micrometer and 533+40.63 micrometer respectively in group B. Conclusion: Quantitative assessment and comparison of endothelial cell count and central corneal thickness shows that at end of the study, there was no remarkable difference in mean values of endothelial cell count and central corneal thickness between two methods. Journal of Monno Medical College December, 2023; 9 (2):37-40

Advancements in Polymer Biomaterials as Scaffolds for Corneal Endothelium Tissue Engineering

Corneal endothelial dysfunction is a leading cause of vision loss globally, frequently requiring corneal transplantation. However, the limited availability of donor tissues, particularly in developing countries, has spurred on the exploration of tissue engineering strategies, with a focus on polymer biomaterials as scaffolds for corneal endotlhelium regeneration. This review provides a comprehensive overview of the advancements in polymer biomaterials, focusing on their role in supporting the growth, differentiation, and functional maintenance of human corneal endothelial cells (CECs). Key properties of scaffold materials, including optical clarity, biocompatibility, biodegradability, mechanical stability, permeability, and surface wettability, are discussed in detail. The review also explores the latest innovations in micro- and nano-topological morphologies, fabrication techniques such as electrospinning and 3D/4D bioprinting, and the integration of drug delivery systems into scaffolds. Despite significant progress, challenges remain in translating these technologies to clinical applications. Future directions for research are highlighted, including the need for improved biomaterial combinations, a deeper understanding of CEC biology, and the development of scalable manufacturing processes. This review aims to serve as a resource for researchers and clinician–scientists seeking to advance the field of corneal endothelium tissue engineering.

COL8A2 activation enhances function of corneal endothelial cells through HIPPO signaling/mitochondria pathway

Corneal endothelial cells (CECs) are essential for maintaining corneal transparency and hydration through their barrier and pump functions. The COL8A2 gene encodes a component of the extracellular matrix of the cornea, which is crucial for the normal functioning of these cells. Mutations in COL8A2 are linked to corneal dystrophies, emphasizing the gene's importance in corneal health. The purpose of this research is to explore the effects of COL8A2 activation within CECs, to understand its contribution to cellular behavior and health. COL8A2 CRISPR/dCas9 activation system (aCOL8A2) was used to activate the COL8A2. In rats, wound healing and mitochondrial function were assessed after COL8A2 activation. As a result, aCOL8A2 promoted wound healing of rat corneal endothelium by increasing mitochondrial membrane potential. In cultured human CECs, proteomic analysis was performed to screen and identify the differential protein profiles between control and aCOL8A2 cells. Western blot was used to validate the differential proteins from both cells. Mitochondrial function and intracellular distribution were assessed by measuring ATP production and mitochondrial membrane potential. In cultured human CECs, aCOL8A2 increased COL8A2 and phospho-YAP levels. Transendothelial electrical resistance (TEER) was increased and actin cytoskeleton was attenuated by aCOL8A2. Gene ontology analysis revealed that the proteins were mainly involved in the regulation of folate biosynthesis, ECM-receptor interaction, cell differentiation, NADP activity and cytoskeleton. ATP production was increased, mitochondrial membrane potential was polarized and mitochondrial distribution was widespread in the aCOL8A2 group. In conclusion, aCOL8A2 induces a regulatory cascade affecting mitochondrial positioning and efficiency, mediated by alterations in the cytoskeletal architecture and the YAP signaling pathway. This sequence of events serves to bolster the functional capacities of corneal endothelial cells, including their pump and barrier functions, essential for corneal health and transparency.

Changes and Influencing Factors of Corneal Endothelial Cells and Central Corneal Thickness after Pediatric Cataract Surgery.

This study aimed to examine the impact of cataract surgery on the corneal endothelium and central corneal thickness (CCT) in pediatric patients, and to identify the factors associated with corneal alterations. This retrospective study included consecutive children undergoing bilateral or unilateral cataract surgery and intraocular lens (IOL) implantation at the Eye Hospital of Wenzhou Medical University, with or without posterior capsulorhexis and anterior vitrectomy, and an age-matched normal control group. This study aimed to assess whether changes in corneal parameters, including CCT, corneal endothelial cell density (CD), average cell area (AVE), standard deviation of size (SD), coefficient of variation (CV), percentage of hexagonal cells (6A) before and after surgery, and endothelial cell loss (ECL) differed among the bilateral cataract, unilateral cataract, and control groups. Furthermore, the potential effects of anterior vitrectomy, axial length (AL), preoperative anterior chamber depth (ACD), surgical duration, horizontal corneal diameter (HCD), intraoperative pupil diameter (PD), and the number of corneal sutures on corneal endothelial parameters and CCT were investigated. A total of 107 eyes from 107 children were included in the study. In the bilateral cataract group, CD significantly decreased, AVE and CCT significantly increased, and ECL was significantly higher than in the control group. The unilateral cataract group also exhibited a significant increase in CCT. Additionally, the numberofcornealsutures was negatively correlated with CD, and PD was negatively correlated with CV in the unilateral cataract group. Cataract surgery in pediatric patients results in increased CCT, reduced CD, and morphological changes in corneal cells. A greater number of corneal sutures and a smaller PD increased the risk of CD reduction and elevated CV in the unilateral cataract group, underscoring the need for ophthalmologists to minimize corneal damage in these children.

Effects of Eye Bank Donor Age Expansion on Corneal Endothelial Cell Density and Surgeon Tissue Acceptance

Effects of Eye Bank Donor Age Expansion on Corneal Endothelial Cell Density and Surgeon Tissue Acceptance

Associations between endothelial cell characteristics and corneal topography findings in different stages of keratoconus.

This study aimed to compare and correlate specular microscope indices and corneal topography indices in different stages of keratoconus. Two hundred forty-six eyes of 123 participants were enrolled in the study. Corneal topography was performed using Sirius (CSO, Italy), with a rotating Scheimpflug camera and a Placido disc topographer. Corneal endothelial cell indices were assessed using a specular microscope (Nidek CEM-530, Japan). Eyes were graded as keratoconus stages 0-4 according to the Amsler-Krumeich classification. Corneal topography and endothelial cell indices were compared among the groups, and the correlations between them were analyzed. The mean age of the patients was 23.26 ± 6.75years (range, 14-47years). Forty-eight cases were male (39%) and 75 were female (61%). There were no statistically significant age (p = 0.578) or sex ratio (p = 0.529) differences between the groups. Twenty-nine eyes were included in the control group (11.78%), while 41 (16.67%) had stage 1 keratoconus, 88 (35.77%) had stage 2, and 88 (35.77%) had stage 3. Measurement was not possible in stage 4 keratoconus. No statistically significant difference was determined in specular microscopy values according to the stage of keratoconus, except for the number of analyzed cells (NUM) (p > 0.05). The lowest NUM values were observed in stages 1, 2, and 3, with values of 184.34 ± 67.62 cells/mm2, 155.07 ± 59.48 cells/mm2, and 127.06 ± 64.39 cells/mm2, respectively (p = 0.001). In the keratoconus group, weak statistically significant negative correlations were observed between NUM and SimK1, SimK2, KVf, BCVf, KVb, and BCVb, while a weak positive correlation was noted between NUM and central corneal thickness (p < 0.05). NUM seems to decrease, while endothelial cell density exhibits no significant changes, with the progression of keratoconus. It appears that as keratoconus index values increase, NUM may decrease in different stages of keratoconus.

Comprehensive combined analysis of physician-initiated phase II and III clinical trials on a cultured human corneal endothelial cell product for treating bullous keratopathy.

To evaluate the efficacy and safety of a cultured human corneal endothelial cell (cHCEC) product in eyes with bullous keratopathy (BK). Combined analysis of multicenter phase II and III clinical trials. This analysis involved 15 BK eyes in the phase II trial and 12 BK eyes in the phase III trial that underwent cHCEC transplant therapy. Safety was assessed in all the cases. Efficacy was assessed in 17 cases with exclusion of the low- and medium-dose groups in the phase II trial. The primary endpoint was a corneal endothelial cell density of 1000 cells/mm2 or more at 24 weeks post-transplant, which was attained in 94.1% of the eyes (16 of 17), with a 95% CI of 71.3-99.9%. Additionally, 82.4% of the eyes (14 of 17) met the secondary endpoint of reduction in corneal thickness to less than 630 µm without corneal epithelial edema within the same time frame, with a 95% CI of 56.6-96.2%. The mean decrease in corneal thickness from baseline to 24 weeks post-transplant was -187.4 µm (95% CI, -240.2 µm to -134.5 µm). Furthermore, all the eyes exhibited improvement in best-corrected visual acuity from baseline to 24 weeks post-transplant (95% CI, 80.5-100.0%). By 24 weeks post-transplant, 88.9% of the patients (24 of 27) had experienced adverse events, which were mostly local, mild, and transient. The cHCEC product of this study reconstitutes the corneal endothelial layer with high cellular density and restores corneal thickness and improves visual acuity.

Hyperglycemia-depleted glutamine contributes to the pathogenesis of diabetic corneal endothelial dysfunction

Diabetic mellitus causes various complications, including the corneal endothelial dysfunction (CED) that leads to corneal edema and vision loss, especially in the DM patients with intraocular surgeries. However, the pathogenic mechanism of hyperglycemia-caused CED remains incomplete understood. Here we firstly screened and identified the glutamine contents of anterior humor were significantly reduced in both the type 2 diabetic patients and streptozotocin-induced type 1 diabetic mice. To explore the potential therapeutic effects of glutamine supplement on the protection of diabetic corneal endothelial dysfunction, we performed the anterior chamber perfusion with the addition of L-alanyl-L-glutamine (Ala-Gln), and confirmed that Ala-Gln supplement not only accelerated the resolution of corneal edema and recovery of corneal thickness, but also preserved the regular arrangement and barrier-pomp function of corneal. Mechanistically, we revealed that the supplements of Ala-Gln protect corneal endothelial cells from the deleterious effects of high glucose-induced oxidative stress, mitochondrial dysfunction, and cell apoptosis. Overall, these results indicate the glutamine depletion plays an important role in the diabetic corneal endothelial dysfunction, while the Ala-Gln supplement during intraocular surgery provide an effective prevention strategy through regulating the redox homeostasis and mitochondrial function of corneal endothelial cells.

Compared to Trabeculectomy, Ex-Press® Surgery Significantly Decreased the Loss of Corneal Endothelial Cell Density in Low-Intraocular-Pressure Glaucoma: 3-Year Follow-Up.

We compared the corneal endothelial cell loss between trabeculectomy (Trab) and Ex-Press® surgery (EXP) for low-intraocular pressure (IOP) glaucoma patients. This was a single-facility retrospective study. We analyzed the cases of patients with primary open-angle glaucoma (POAG) and pre-operative IOP ≤ 21 mmHg who had undergone Trab or EXP surgery and were followed for >3 years. Noncontact specular microscopy was used to determine the corneal endothelial cell density (CED) before and after Trab or EXP surgery. We measured the CED at 12, 24, and 36 months post-surgery. We compared the CED values and CED survival ratio after both surgeries using paired t-tests. We included 39 eyes that underwent Trab and 36 eyes that underwent EXP surgery. In the Trab group, the mean CED value had decreased from 2333 ± 399 at baseline to 2066 ± 587 cells/mm2 after 3 years. In the EXP group, the mean CED value had decreased from 2320 ± 393 at baseline to 2229 ± 460 cells/mm2 after 3 years. The survival ratio of CED at >3 years was 89.3 ± 14.2% (Trab group) and 95.6 ± 11.1% (EXP group); compared to the Trab surgery, the EXP surgery thus significantly decreased the CED loss (p = 0.037). No case resulted in bullous keratopathy. Compared to trabeculectomy, Ex-Press® surgery appears to be a safer surgical method with regard to the endothelial cell loss risk.

Corneal endothelial density and morphology in long-term soft contact lens users in Japan: a retrospective cross-sectional study of 17,732 eyes

Purpose There is a lack of long-term and large-scale studies on the adverse effects of soft contact lenses (SCLs) on the corneal endothelia of Asian populations. Here, we aimed to examine the effects of long-term SCL use on corneal endothelial density and morphology. Materials and Methods This retrospective study involved consecutive patients at the Miyata Eye Hospital (Miyazaki, Japan), who had used SCLs for more than 1 year. Patients with ophthalmological disorders without refractive errors were excluded. The period of SCL use, SCL type, corneal endothelial cell density (ECD), appearance rate of hexagonal cells (HEX), and coefficient of variation of cells (CV) were analyzed. Results In total, 17,732 eyes of 8866 patients were included in the analysis (age, 26.0 ± 8.8 years). The mean period of SCL use was 6.3 ± 5.4 years. Multivariate regression analysis revealed that ECD and HEX were significantly negatively correlated with the period of SCL use, age, and sex (p < 0.001 for all). The CV was significantly positively correlated with the period of use (p < 0.001), sex (p = 0.002), and age (p < 0.001). Conclusions Corneal ECD, HEX, and CV were significantly associated with the period of SCL use in long-term users. It is essential to regularly check the corneal endothelium in patients with a history of long-term SCL use.