Proteomic analysis of corneal endothelial cell-descemet membrane tissues reveals influence of insulin dependence and disease severity in type 2 diabetes mellitus

Exploring single-cell RNA sequencing as a decision-making tool in the clinical management of Fuchs' endothelial corneal dystrophy

Single-cell RNA sequencing (scRNA-seq) has enabled the identification of novel gene signatures and cell heterogeneity in numerous tissues and diseases. Here we review the use of this technology for Fuchs' Endothelial Corneal Dystrophy (FECD). FECD is the most common indication for corneal endothelial transplantation worldwide. FECD is challenging to manage because it is genetically heterogenous, can be autosomal dominant or sporadic, and progress at different rates. Single-cell RNA sequencing has enabled the discovery of several FECD subtypes, each with associated gene signatures, and cell heterogeneity. Current FECD treatments are mainly surgical, with various Rho kinase (ROCK) inhibitors used to promote endothelial cell metabolism and proliferation following surgery. A range of emerging therapies for FECD including cell therapies, gene therapies, tissue engineered scaffolds, and pharmaceuticals are in preclinical and clinical trials. Unlike conventional disease management methods based on clinical presentations and family history, targeting FECD using scRNA-seq based precision-medicine has the potential to pinpoint the disease subtypes, mechanisms, stages, severities, and help clinicians in making the best decision for surgeries and the applications of therapeutics. In this review, we first discuss the feasibility and potential of using scRNA-seq in clinical diagnostics for FECD, highlight advances from the latest clinical treatments and emerging therapies for FECD, integrate scRNA-seq results and clinical notes from our FECD patients and discuss the potential of applying alternative therapies to manage these cases clinically.

Rat Model of Type 2 Diabetes Mellitus Recapitulates Human Disease in the Anterior Segment of the Eye

Changes in the anterior segment of the eye due to type 2 diabetes mellitus (T2DM) are not well-characterized, in part due to the lack of a reliable animal model. This study evaluates changes in the anterior segment, including crystalline lens health, corneal endothelial cell density, aqueous humor metabolites, and ciliary body vasculature, in a rat model of T2DM compared with human eyes. Male Sprague-Dawley rats were fed a high-fat diet (45% fat) or normal diet, and rats fed the high-fat diet were injected with streptozotocin i.p. to generate a model of T2DM. Cataract formation and corneal endothelial cell density were assessed using microscopic analysis. Diabetes-related rat aqueous humor alterations were assessed using metabolomics screening. Transmission electron microscopy was used to assess qualitative ultrastructural changes ciliary process microvessels at the site of aqueous formation in the eyes of diabetic rats and humans. Eyes from the diabetic rats demonstrated cataracts, lower corneal endothelial cell densities, altered aqueous metabolites, and ciliary body ultrastructural changes, including vascular endothelial cell activation, pericyte degeneration, perivascular edema, and basement membrane reduplication. These findings recapitulated diabetic changes in human eyes. These results support the use of this model for studying ocular manifestations of T2DM and support a hypothesis postulating blood-aqueous barrier breakdown and vascular leakage at the ciliary body as a mechanism for diabetic anterior segment pathology.

Targeting the NRF2 pathway: A promising approach for corneal endothelial dysfunction

Maintaining corneal endothelial function is required for vision, and corneal endothelial dysfunction is a major cause of visual deficits and blindness worldwide. To date there has been a dearth of innovation for therapeutics targeting the corneal endothelium. However, recent advances in understanding the role of oxidative stress and mitochondrial dysfunction have revealed potential avenues for the development of new therapies. This review summarizes recent developments in elucidating the role of the NRF2 pathway in corneal endothelial health and disease, focusing specifically on Fuchs' endothelial corneal dystrophy and the loss of corneal endothelial cells associated with cataract surgery. The pro-mitochondrial and antioxidant phenotype elicited by NRF2 activation offers a promising opportunity for new therapeutics for the diseased corneal endothelium.

Early effects of intravitreal anti-VEGF agents on cornea and visual acuity in patients with diabetic retinopathy

PURPOSE

This study aimed to investigate the early effects of intravitreal anti-vascular endothelial growth factor (anti-VEGF) agents on the cornea and visual acuity in patients with diabetic retinopathy (DR).

METHODS

This retrospective study enrolled patients who were administered conbercept or ranibizumab to treat DR. Fundus photograph, fluorescein angiograph, and optical coherence tomography were preoperatively performed. The patients were classified into two groups: nonproliferative DR (NPDR) and PDR. Best-corrected visual acuity (BCVA), specular microscopy, central corneal thickness (CCT), and intraocular pressure were obtained before injection and at 1 day and 7 days after injection. The effects of anti-VEGF agents on BCVA and CCT were compared between the groups receiving conbercept and ranibizumab and between NPDR and PDR eyes.

RESULTS

A total 38 eyes (30 patients) were enrolled in this study. Twenty-one eyes received conbercept, and 17 eyes received ranibizumab. Twenty eyes were classified as NPDR and 18 eyes as PDR. No significant differences were found between the groups receiving conbercept and ranibizumab in the increase in BCVA nor in the increase of CCT at 1 day and 7 days after injection. As compared with NPDR eyes, PDR eyes demonstrated a significantly greater increase in CCT (-5.3 ± 3.7 vs. 6.5 ± 2.9 μm, P = 0.02 < 0.05) but not in BCVA (P = 0.33) at 1 day after injection. At 7 days after injection, no significant differences were found in the increase in BCVA nor in the increase of CCT between NPDR eyes and PDR eyes.

CONCLUSION

Intravitreal administration of anti-VEGF agents could cause a small but significant greater increase in CCT in PDR than in NPDR eyes in the early period. In patients with DR, no significant difference was found between conbercept and ranibizumab in the early effects on the visual acuity nor in the cornea.

Type II Diabetes Mellitus Causes Extracellular Matrix Alterations in the Posterior Cornea That Increase Graft Thickness and Rigidity

Purpose

There is a pressing need to investigate the impact of type II diabetes mellitus on the posterior cornea in donor tissues given its increasing prevalence and potential impact on endothelial keratoplasty surgical outcomes.

Methods

Immortalized human cultured corneal endothelial cells (CECs; HCEC-B4G12) were grown in hyperglycemic media for 2 weeks. Extracellular matrix (ECM) adhesive glycoprotein expression and advanced glycation end products (AGEs) in cultured cells and corneoscleral donor tissues, as well as the elastic modulus for the Descemet membrane (DMs) and CECs of diabetic and nondiabetic donor corneas, were measured.

Results

In CEC cultures, increasing hyperglycemia resulted in increased transforming growth factor beta-induced (TGFBI) protein expression and colocalization with AGEs in the ECM. In donor corneas, the thicknesses of the DM and the interfacial matrix (IFM) between the DM and stroma both increased from 8.42 ± 1.35 µm and 0.504 ± 0.13 µm in normal corneas, respectively, to 11.13 ± 2.91 µm (DM) and 0.681 ± 0.24 µm (IFM) in non-advanced diabetes (P = 0.013 and P = 0.075, respectively) and 11.31 ± 1.76 µm (DM) and 0.744 ± 0.18 µm (IFM) in advanced diabetes (AD; P = 0.0002 and P = 0.003, respectively). Immunofluorescence in AD tissues versus controls showed increased AGEs (P < 0.001) and markedly increased labeling intensity for adhesive glycoproteins, including TGFBI, that colocalized with AGEs. The elastic modulus significantly increased between AD and control tissues for the DMs (P < 0.0001) and CECs (P < 0.0001).

Conclusions

Diabetes and hyperglycemia alter human CEC ECM structure and composition, likely contributing to previously documented complications of endothelial keratoplasty using diabetic donor tissue, including tearing during graft preparation and reduced graft survival. AGE accumulation in the DM and IFM may be a useful biomarker for determining diabetic impact on posterior corneal tissue.

The soil and the seed: The relationship between Descemet's membrane and the corneal endothelium

Descemet's membrane (DM), the basement membrane of the corneal endothelium, is formed from the extracellular matrix (ECM) secreted by corneal endothelial cells. The ECM supports the growth and function of the corneal endothelial cells. Changes to DM are central to the diagnosis of the most common corneal endothelial disease, Fuchs endothelial corneal dystrophy (FECD). Changes in DM are also noted in systemic diseases such as diabetes mellitus. In FECD, the DM progressively accumulates guttae, "drop-like deposits" that disrupt the corneal endothelial cell monolayer. While the pathophysiologic changes to corneal endothelial cells in the course of FECD have been well described and reviewed, the changes to DM have received limited attention. The reciprocity of influence between the corneal endothelial cells and DM demands full attention to the latter in our search for novel treatment and preventive strategies. In this review, we discuss what is known about the formation and composition of DM and how it changes in FECD and other conditions. We review characteristics of guttae and the interplay between corneal endothelial cells and guttae, particularly as it might apply to future cell-based and genetic therapies for FECD.

Extracellular vesicles of human diabetic retinopathy retinal tissue and urine of diabetic retinopathy patients are enriched for the junction plakoglo bin protein

Introduction

Diabetic Retinopathy (DR) is a potentially blinding retinal disorder that develops through the pathogenesis of diabetes. The lack of disease predictors implies a poor prognosis with frequent irreversible retinal damage and vision loss. Extracellular Vesicles (EVs) present a novel opportunity for pre-symptomatic disease diagnosis and prognosis, both severely limited in DR. All biological fluids contain EVs, which are currently being studied as disease biomarkers. EV proteins derived from urine have emerged as potential noninvasive biomarkers.

Methods

In this study, we isolated EVs from DR retinal tissue explants and from DR patients' urine, and characterized the vesicles, finding differences in particle number and size. Next, we performed proteomic analysis on human explanted DR retinal tissue conditioned media, DR retinal EVs and DR urinary EVs and compared to normal human retinal tissue, retinal EVs, and urinary EVs, respectively.

Results

Our system biology analysis of DR tissue and EV expression profiles revealed biological pathways related to cell-to-cell junctions, vesicle biology, and degranulation processes. Junction Plakoglobin (JUP), detected in DR tissue-derived EVs and DR urinary EVs, but not in controls, was revealed to be a central node in many identified pathogenic pathways. Proteomic results were validated by western blot. Urinary EVs obtained from healthy donors and diabetic patient without DR did not contain JUP.

Conclusion

The absence of JUP in healthy urinary EVs provide the basis for development of a novel Diabetic Retinopathy biomarker, potentially facilitating diagnosis.

Metabolic and proteomic indications of diabetes progression in human aqueous humor

Diabetes mellitus is a multiorgan systemic disease impacting numerous ocular structures that results in significant ocular morbidity and often results in more frequent corneal and glaucoma surgeries for affected individuals. We hypothesize that the systemic metabolic and proteomic derangement observed in the progression of diabetes influences the composition of the aqueous humor (AH), which ultimately impacts the anterior segment health of the eye. To identify changes associated with diabetes progression, we mapped the metabolite profile and proteome of AH samples from patients with varying severities of type II diabetes (T2DM). Patients were classified as nondiabetic (ND or control), non-insulin-dependent diabetic without advanced features of disease (NAD-ni), insulin-dependent diabetic without advanced features (NAD-i), or diabetic with advanced features (AD). AH samples collected from the anterior chamber during elective ophthalmic surgery were evaluated for metabolite and protein expression changes associated with diabetic severity via gas chromatography/mass spectrometry and ultra-high performance liquid chromatography tandem mass spectrometry, respectively. Metabolic and proteomic pathway analyses were conducted utilizing MetaboAnalyst 4.0 and Ingenuity Pathway Analysis. A total of 14 control, 12 NAD-ni, 4 NAD-I, and 14 AD samples were included for analysis. Elevated levels of several branched amino acids (e.g., valine, leucine, isoleucine), and lipid metabolites (e.g., palmitate) were found only with increasing diabetic severity (i.e., the AD group). Similar proteomic trends were noted in amino acid and fatty acid metabolism and the unfolded protein/stress response. These results represent the first report of both metabolomic and proteomic evaluation of aqueous humor. Diabetes results in metabolic and proteomic perturbations detectable in the AH, and unique changes become manifest as T2DM severity worsens. Changes in AH composition may serve as an indicator of disease severity, risk assessment of anterior segment cells and structures, and potential future therapies.

Corneal endothelial cell morphology and optical coherence tomography findings in children with type 1 diabetes mellitus

Purpose

To evaluate central macular thickness, retinal nerve fibre layer thickness, corneal endothelial cell density and central corneal thickness in children with Type 1 Diabetes Mellitus (DM).

Methods

Thirty children with Type 1 DM and 30 age-matched children as controls were examined. Central macular thickness (CMT) and four quadrants of retinal nerve fibre layer thickness (RNFLT) were measured by optical coherence tomography (OCT), while endothelial cell density (ECD), coefficient of variation in cell size (CV), hexagonality (HEX) and central corneal thickness (CCT) were measured by noncontact specular microscopy.

Results

The mean ECD was 2810.77  ±  273.47 cells/mm2 and the mean hexagonality ratio was 49.77  ±  13.2 both were significantly lower (p < 0.001, p  =  0.037 respectively) in the diabetic group compared to the control group. The mean CV was 37.6  ±  7.27, it was significantly higher (p  =  0.024) in the diabetic group than the control group. The mean corneal thickness was greater in the DM group than the controls, but the difference was not significant (p  =  0.176). There were no significant differences in CMT or RNFLT between the two groups. There was a negative correlation between the HbA1c levels and the thickness of the superior quadrants of RNFL (r  =  -0.406, p  =  0.026). The duration of diabetes had no significant correlations with the corneal and retinal parameters.

Conclusion

The diabetic children had changes in corneal endothelial morphology and there was a negative correlation between HbA1c levels and superior quadrant of RNFLT.

Ubiquinol Supplementation of Donor Tissue Enhances Corneal Endothelial Cell Mitochondrial Respiration

PURPOSE

To determine whether ubiquinol improves mitochondrial function and cell viability in human donor corneal endothelial cells during hypothermic corneal tissue storage.

METHODS

Endothelial cell Descemet membrane tissues were treated with 10 μM ubiquinol, the reduced form of the antioxidant coenzyme Q10, for 5 days in Optisol-GS storage media before assaying for mitochondrial activity using extracellular flux analysis of oxygen consumption. In addition, endothelial cell Descemet membrane tissues were analyzed for cell viability using apoptosis and necrosis assays. Control tissues from mate corneas were treated with diluent only, and comparisons were analyzed for differences.

RESULTS

A total of 13 donor corneal tissues with a mean (SEM) preservation time of 11.8 days (0.4) were included for the analysis. Treatment with 10 μM ubiquinol increased spare respiratory capacity by 174% (P = 0.001), maximal respiration by 93% (P = 0.003), and proton leak by 80% (P = 0.047) compared with controls. Cells treated with ubiquinol had no significant change in cell necrosis or apoptosis.

CONCLUSIONS

Preliminary testing in donor corneal tissue at specified doses indicates that ubiquinol may be a useful biocompatible additive to hypothermic corneal storage media that increases corneal endothelial cell mitochondrial function. Additional investigations are indicated to further study and optimize the dose and formulation of ubiquinol for use in preserving donor corneal tissue function during hypothermic storage.

Corneal proteome and differentially expressed corneal proteins in highly myopic chicks using a label-free SWATH-MS quantification approach

Myopia, or short-sightedness, is a highly prevalent refractive disorder in which the eye's focal length is too short for its axial dimension in its relaxed state. High myopia is associated with increased risks of blinding ocular complications and abnormal eye shape. In addition to consistent findings on posterior segment anomalies in high myopia (e.g., scleral remodeling), more recent biometric and biomechanical data in myopic humans and animal models also indicate anterior segment anomalies (e.g., corneal biomechanical properties). Because the cornea is the anterior-most ocular tissue, providing essential refractive power and physiological stability, it is important to understand the biochemical signaling pathway during myopia development. This study first aimed to establish the entire chicken corneal proteome. Then, using the classical form deprivation paradigm to induce high myopia in chicks, state-of-the-art bioinformatics technologies were applied to identify eight differentially expressed proteins in the highly myopic cornea. These results provide strong foundation for future corneal research, especially those using chicken as an animal model for myopia development.

Advances in Current Diabetes Proteomics: From the Perspectives of Label- free Quantification and Biomarker Selection

BACKGROUND

Due to its prevalence and negative impacts on both the economy and society, the diabetes mellitus (DM) has emerged as a worldwide concern. In light of this, the label-free quantification (LFQ) proteomics and diabetic marker selection methods have been applied to elucidate the underlying mechanisms associated with insulin resistance, explore novel protein biomarkers, and discover innovative therapeutic protein targets.

OBJECTIVE

The purpose of this manuscript is to review and analyze the recent computational advances and development of label-free quantification and diabetic marker selection in diabetes proteomics.

METHODS

Web of Science database, PubMed database and Google Scholar were utilized for searching label-free quantification, computational advances, feature selection and diabetes proteomics.

RESULTS

In this study, we systematically review the computational advances of label-free quantification and diabetic marker selection methods which were applied to get the understanding of DM pathological mechanisms. Firstly, different popular quantification measurements and proteomic quantification software tools which have been applied to the diabetes studies are comprehensively discussed. Secondly, a number of popular manipulation methods including transformation, pretreatment (centering, scaling, and normalization), missing value imputation methods and a variety of popular feature selection techniques applied to diabetes proteomic data are overviewed with objective evaluation on their advantages and disadvantages. Finally, the guidelines for the efficient use of the computationbased LFQ technology and feature selection methods in diabetes proteomics are proposed.

CONCLUSION

In summary, this review provides guidelines for researchers who will engage in proteomics biomarker discovery and by properly applying these proteomic computational advances, more reliable therapeutic targets will be found in the field of diabetes mellitus.

Corneal endothelial cell density during diabetes mellitus and ocular diabetes complications treatment

Diabetes mellitus may affect the cornea at various levels. Ocular surface changes and dry eye had been studied. Researchers are concerned that medical treatment of diabetes or retinal complications may result in endothelial damage and cell loss. This report summarizes the possibility of endothelial cell loss in diabetic patients. A decrease in endothelial cell density (ECD) in diabetic patients has been reported. In addition, corneal thickness may increase in diabetic patients. Significant endothelial cell loss has been demonstrated in long-term disease and in cases of poor metabolic control. No association between the use of oral hypoglycemics and ECD has been reported. There is also no evidence of an association between the use of insulin and corneal endothelial damage. No difference in ECD among the various degrees of retinopathy or with a history of photocoagulation has been shown. Regarding the studies comparing diabetic and non-diabetic patients undergoing cataract surgery, in all cases, the decrease in ECD is higher in diabetic patients than that seen in non-diabetic patients. However, there is no evidence of increased endothelial damage in diabetics compared to non-diabetics during vitreo-retinal surgery in phakic eyes. No significant changes in corneal endothelium after intravitreal anti-VEGF injections have been referenced.

The effects of diabetes mellitus on the corneal endothelium: A review

The corneal endothelium plays a critical role in maintaining corneal clarity. There is an expected decline in cell density with age and disease, and maintaining the health of this cell layer is important as corneal endothelial cells generally are amitotic in vivo. Diabetes mellitus is a highly prevalent disease that damages the corneal endothelium. Diabetes causes structural and functional impairments in the corneal endothelium that decrease cellular reserve in response to stress. These effects have implications to consider for diabetic patients undergoing anterior segment surgery, and for corneal surgeons who use diabetic donor tissue and treat diabetic patients. In this review, we discuss the specifics of how diabetes mellitus impacts the corneal endothelium including alterations in cell morphology, cell density, ultrastructure, pump and barrier function, cataract surgery outcomes, and corneal transplant outcomes with attention to the use of diabetic donor tissue and diabetic transplant recipients.

Corneal alteration and pathogenesis in diabetes mellitus

The incidence of diabetes mellitus (DM) and its complications have increased considerably worldwide. Diabetic keratopathy is the major complication of the cornea characterized by delayed corneal wound healing, decreasing corneal epithelial sensitivity, and recurrent corneal ulcers. There is accumulating evidence that diabetic keratopathy is correlated with the hyperglycemic state. Different corneal components may produce different alterations under hyperglycemia. In addition, diabetic nerve alteration may become a novel biomarker of early-stage DM. Abnormalities of the corneal nerve plexus have been associated with diabetic inflammatory states. There is rapidly growing evidence based on investigations of diabetic corneal nerves through in vivo confocal microscopy. Understanding the molecular pathogenesis caused by hyperglycemia may assist in the identification of novel biomarkers, as well as therapeutic targets for early treatment. This review mainly summarizes recent findings on corneal alteration and pathogenesis in DM.

Effect of Graft Attachment Status and Intraocular Pressure on Descemet Stripping Automated Endothelial Keratoplasty Outcomes in the Cornea Preservation Time Study

PURPOSE

To examine the association of donor, recipient, and operative factors on graft dislocation after Descemet stripping automated endothelial keratoplasty (DSAEK) in the Cornea Preservation Time Study (CPTS) as well as the effects of graft dislocation and elevated IOP on graft success and endothelial cell density (ECD) 3 years postoperatively.

DESIGN

Cohort study within a multi-center, double-masked, randomized clinical trial.

METHODS

1090 individuals (1330 study eyes), median age 70 years, undergoing DSAEK for Fuchs endothelial corneal dystrophy (94% of eyes) or pseudophakic or aphakic corneal edema (6% of eyes). Recipient eyes receiving donor corneal tissue randomized by preservation time (PT) of 0-7 days (N = 675) or 8-14 days (N = 655) were monitored for early or late graft failure through 3 years. Donor, recipient, operative, and postoperative parameters were recorded including graft dislocation (GD), partial detachment, and pre- and post-operative IOP. Pre- and postoperative central donor ECD were determined by a central image analysis reading center. Proportional hazards, mixed effects, and logistic regression models estimated risk ratios and (99% confidence intervals).

RESULTS

Three independent predictive factors for GD were identified: a history of donor diabetes (odds ratio [OR]: 2.29 [1.30, 4.02]), increased pre-lamellar dissection central corneal thickness (OR: 1.13 [1.01, 1.27] per 25µ increase), and operative complications (OR: 2.97 [1.24, 7.11]). Among 104 (8%) eyes with GD, 30 (28.9%) developed primary donor or early failure and 5 (4.8%) developed late failure vs. 15 (1.2%; P < .001) and 29 (2.4%; P = .04), respectively, of 1226 eyes without GD. 24 (2%) of 1330 study eyes had early acutely elevated postoperative IOP that was associated with a higher risk of graft failure through 3 years (hazard ratio: 3.42 [1.01, 11.53]), but not with a lower mean 3-year ECD (mean difference 61 (-479, 601) cells/mm², P = .77). History of elevated postoperative IOP beyond 1 month was not significantly associated with 3-year graft success or ECD.

CONCLUSIONS

Donor diabetes, increased donor corneal thickness, and intraoperative complications were associated with an increased risk of GD. Early acutely elevated postoperative IOP and GD significantly increased the risk for graft failure following DSAEK.

An Update on Corneal Biomechanics and Architecture in Diabetes

In the last decade, we have witnessed substantial progress in our understanding of corneal biomechanics and architecture. It is well known that diabetes is a systemic metabolic disease that causes chronic progressive damage in the main organs of the human body, including the eyeball. Although the main and most widely recognized ocular effect of diabetes is on the retina, the structure of the cornea (the outermost and transparent tissue of the eye) can also be affected by the poor glycemic control characterizing diabetes. The different corneal structures (epithelium, stroma, and endothelium) are affected by specific complications of diabetes. The development of new noninvasive diagnostic technologies has provided a better understanding of corneal tissue modifications. The objective of this review is to describe the advances in the knowledge of the corneal alterations that diabetes can induce.

Three kinds of corneal host cells contribute differently to corneal neovascularization

Background

Corneal neovascularization (angiogenesis and lymphangiogenesis) compromises corneal transparency and transplant survival, however, the molecular mechanisms of corneal host epithelial and stromal cells in neovascularization have not yet been fully elucidated. Furthermore, the contribution and mechanism of corneal host endothelial cells involved in neovascularization are largely unexplored.

Methods

Liquid chromatography-mass spectrometry, immunoblotting, and ELISA were used to screen and identify potential neovascularization-related factors in human full-thickness vascularized corneal tissues. Lipopolysaccharide was used to induce inflammation in three kinds of corneal host cells in vitro, including corneal epithelial, stromal, and endothelial cells. Fungus was used to establish an animal model of corneal neovascularization in vivo. Tube formation and spheroid sprouting assays were used to evaluate the contribution of three kinds of corneal host cells to the degree of neovascularization under various stimuli. Matrix metalloproteinase (MMP)-2, alpha-crystallin A chain (CRYAA), galectin-8, Bcl-2, neuropilin-2, MMP-9 plasmids, and recombinant human fibronectin were used to identify the key proteins of corneal host cells involved in corneal inflammatory neovascularization.

Findings

All three kinds of corneal host cells influenced corneal neovascularization to varying degrees. MMP-9 in human corneal epithelial cells, MMP-2, and CRYAA in human corneal stromal cells, and MMP-2 and galectin-8 in human corneal endothelial cells are potential key proteins that participate in corneal inflammatory neovascularization.

Interpretation

Our data indicated that both the effects of key proteins and corneal host cells involved should be considered for the treatment of corneal inflammatory neovascularization.

Donor, Recipient, and Operative Factors Associated With Increased Endothelial Cell Loss in the Cornea Preservation Time Study

Importance

Determining factors associated with endothelial cell loss after Descemet stripping automated endothelial keratoplasty (DSAEK) could improve long-term graft survival.

Objective

To evaluate the associations of donor, recipient, and operative factors with endothelial cell density (ECD) 3 years after DSAEK in the Cornea Preservation Time Study.

Design, Setting, and Participants

This cohort study was a secondary analysis of data collected in a multicenter, double-masked, randomized clinical trial. Forty US clinical sites with 70 surgeons participated, with donor corneas provided by 23 US eye banks. Individuals undergoing DSAEK for Fuchs dystrophy or pseudophakic/aphakic corneal edema were included.

Interventions

The DSAEK procedure, with random assignment of a donor cornea with a preservation time of 0 to 7 days or 8 to 14 days.

Main Outcomes and Measures

Endothelial cell density at 3 years as determined by a reading center from eye bank and clinical specular or confocal central endothelial images.

Results

The study included 1090 participants (median age, 70 years) with 1330 affected eyes (240 bilateral cases [22.0%]), who underwent DSAEK for Fuchs dystrophy (1255 eyes [94.4%]) or pseudophakic/aphakic corneal edema (PACE) (75 eyes [5.6%]). Of these, 801 eyes (60.2%) belonged to women and 1207 (90.8%) to white individuals. A total of 749 participants (913 eyes; 164 [21.9%] bilateral cases) had functioning grafts with acceptable endothelial images preoperatively and at 3 years postoperatively and were included in this analysis. Factors associated with a lower ECD at 3 years (estimated effect with 99% CI) in the final multivariable model included donors with diabetes (-103 [-196 to -9] cells/mm2), lower screening ECD (-234 [-331 to -137] per 500 cells/mm2), recipient diagnosis of PACE (-257 [-483 to -31] in cells/mm2), and operative complications (-324 [-516 to -133] in cells/mm2). Endothelial cell loss (ECL) from a preoperative measurement to a 3-year postoperative measurement was 47% (99% CI, 42%-52%) for participants receiving tissue from donors with diabetes vs 43% (99% CI, 39%-48%) without diabetes; it was 53% (99% CI, 44%-62%) for participants diagnosed with PACE vs 44% (99% CI, 39%-49%) for those diagnosed with Fuchs dystrophy, and 55% (99% CI, 48%-63%) in participants who experienced operative complications vs 44% (99% CI, 39%-48%) in those who did not. No other donor, recipient, or operative factors were significantly associated with 3-year ECD.

Conclusions and Relevance

Donor diabetes, lower screening ECD, a PACE diagnosis in the recipient, and operative complications were associated with lower ECD at 3 years after DSAEK surgery and may be associated with long-term graft success. While causation cannot be inferred, further studies on the association of donor diabetes and PACE in recipients with lower 3-year ECD warrant further study.

Donor, Recipient, and Operative Factors Associated with Graft Success in the Cornea Preservation Time Study

PURPOSE

To associate donor, recipient, and operative factors with graft success 3 years after Descemet stripping automated endothelial keratoplasty (DSAEK) in the Cornea Preservation Time Study (CPTS).

DESIGN

Cohort study within a multicenter, double-masked, randomized clinical trial.

PARTICIPANTS

One thousand ninety individuals (1330 study eyes) with a median age of 70 years undergoing DSAEK for Fuchs endothelial corneal dystrophy (94% of eyes) or pseudophakic or aphakic corneal edema (PACE; 6% of eyes).

METHODS

Eyes undergoing DSAEK were randomized to receive a donor cornea with preservation time (PT) of 0 to 7 days (n = 675) or 8 to 14 days (n = 655). Donor, recipient, and operative parameters were recorded prospectively. Graft failure was defined as regraft for any reason, a graft that failed to clear by 8 weeks after surgery, or an initially clear graft that became and remained cloudy for 90 days. Failure in the first 8 weeks was classified further as primary donor failure or early failure, in the absence or presence of operative complications, respectively. Proportional hazards and logistic regression models were used to estimate risk ratios (RR) and 99% confidence intervals (CIs) for graft failure.

MAIN OUTCOME MEASURES

Graft success at 3 years.

RESULTS

One thousand two hundred fifty-one of 1330 grafts (94%) remained clear at 3 years and were considered successful. After adjusting for PT, tissue from donors with diabetes (RR, 2.35; 99% CI, 1.03-5.33) and operative complications (RR, 4.21; 99% CI, 1.42-12.47) were associated with increased risk for primary or early failure. Preoperative diagnosis of PACE (RR, 3.59; 99% CI, 1.05-12.24) was associated with increased risk for late failure by 3 years after surgery compared with Fuchs dystrophy. Graft success showed little variation among other factors evaluated, including donor age (RR, 1.19 per decade; 99% CI, 0.91-1.56 per decade), preoperative donor endothelial cell density (RR, 1.10 per 500 cells; 99% CI, 0.74-1.63 per 500 cells), graft diameter (RR, 1.22 per 1 mm; 99% CI, 0.39-3.76 per 1 mm), and injector use for graft insertion (RR, 0.92; 99% CI, 0.40-2.10).

CONCLUSIONS

Descemet stripping automated endothelial keratoplasty success in the early and entire postoperative period is more likely when the donor did not have diabetes and was without operative complications and in the long-term postoperative period in recipients with Fuchs dystrophy compared with those with PACE. Mechanisms whereby diabetic donors and PACE recipients reduce the rate of graft success after DSAEK warrant further study.