Evaluation of Sociomedical Factors on Corneal Donor Recovery Using Machine Learning

PURPOSE

To evaluate co-morbid sociomedical conditions affecting corneal donor endothelial cell density and transplant suitability.

METHOD(S)

Corneal donor transplant information was collected from the CorneaGen eye bank between June 1, 2012 and June 30, 2016. A natural language processing algorithm was applied to generate co-morbid sociomedical conditions for each donor. Variables of importance were identified using four machine learning models (random forest, Glmnet, Earth, nnet), for the outcomes of transplant suitability and endothelial cell density. SHAP (SHapley Additive exPlanations) values were generated, with beeswarm and box plots to visualize the contribution of each feature to the models.

RESULTS

With a total of 23,522 unique donors, natural language processing generated 30,573 indices, which were reduced to 41 most common co-morbid sociomedical conditions. For transplant suitability, hypertension ranked the top overall variable of importance in two models. Hypertension, chronic obstructive pulmonary disease, history of smoking, and alcohol use appeared consistently in the top variables of importance. By SHAP feature importance, hypertension (0.042), alcohol use (0.017), ventilation of donor (0.011), and history of smoking (0.010) contributed the most to the transplant suitability model. For endothelial cell density, hypertension was the sociomedical condition of highest importance in three models. SHAP scores were highest among the sociomedical conditions of hypertension (0.037), alcohol use (0.013), myocardial infarction (0.012), and history of smoking (0.011).

CONCLUSION

In a large cohort of corneal donor eyes, hypertension was identified as the most common contributor to machine learning models examining sociomedical conditions for corneal donor transplant suitability and endothelial cell density.

Impact of demographic factors on corneal donor recovery

PURPOSE

Death-to-preservation time (DTP) is a commonly reported, but infrequently studied, measure of efficiency for the corneal tissue procurement process and is a key screening component for corneal tissue suitability for transplantation. It is unknown whether demographic factors such as race, age, or gender may affect DTP.

METHODS

This retrospective cross-sectional study included all deceased-donor eye tissue collected by CorneaGen Eye Banks between June 1, 2012 and June 30, 2016. Exposure variables of race, age, and gender were independently analyzed with the outcome variable, DTP, using three simple linear regression analyzes. Associations were then confirmed by a multiple linear regression analysis within a single model.

RESULTS

A total of 24,138 unique donors were identified from 48,207 donor eyes. Simple linear regression analysis showed that relative to White donors, Black and Hispanic donors were associated with a 2.40 h (95% CI 2.07-2.74 h, p < 0.001) and 2.48 h (95% CI 2.15-2.80 h, p < 0.001) longer mean DTP, respectively. DTP decreased with increasing age, at a rate of 30 min per every 10 years (95% CI 27-33 min, p < 0.001). Male donors were associated with a 35 min (95% CI 26-44 min, p < 0.001) longer DTP relative to female donors. A multiple linear regression confirmed the results of the three simple linear regressions.

CONCLUSIONS

In a large cohort of corneal donors, non-White race, younger age, and male gender were associated with longer DTP.

The impact of donor diabetes on corneal transplant immunity

Corneal transplantation is the most common form of solid tissue grafting, with an approximately 80% to 90% success rate. However, success rates may decline when donor tissues are derived from patients with a history of diabetes mellitus (DM). To evaluate the underlying immunopathologic processes that cause graft rejection, we used streptozotocin-induced type 1 DM (DM1) and transgenic Lepob/ob type 2 DM (DM2) diabetic murine models as donors and nondiabetic BALB/c as recipients. DM resulted in an increased frequency of corneal antigen-presenting cells (APCs) with an acquired immunostimulatory phenotype. Following transplantation, recipients that received either type of diabetic graft showed increased APC migration and T helper type 1 alloreactive cells, impaired functional regulatory T cells, and graft survival. Insulin treatment in streptozotocin-induced diabetic mice led to an increased tolerogenic profile of graft APC, lower T helper type 1 sensitization, and a higher frequency of functional regulatory T cells with high suppressive capacity, reflected in increased graft survival. We conclude that both DM1 and DM2 in donors can impact corneal APC functional phenotype, rendering the tissue more immunogenic and thereby increasing the risk of graft failure.

Characteristics of Semiautomated Endothelial Cell-Density Measurements Among Corneal Donor Eyes

Importance

Endothelial cell density in corneal donor eyes remains a critical component in selecting tissue suitable for corneal transplant.

Objective

To describe an anomaly in endothelial cell density discovered in a large cohort of corneal donor eyes.

Design, Setting, and Participants

Donor information for this cross-sectional study was obtained from the CorneaGen eye bank for donors from June 1, 2012, to June 30, 2016. Endothelial cell density was reported by eye bank technicians for each eye. The retrospective donor data set included donor demographics, endothelial cell count, time of death, medical and surgical history, and suitability for transplant. The donor data set contained information on donated eyes over the 4-year period.

Main Outcomes and Measures

Endothelial cell-density heat map, 2-dimensional binned plots, and bayesian change point analysis.

Results

A total of 48 207 donated eyes were evaluated. Mean (SD) cell count was 2717 (448) cells/mm2, and mean (SD) donor age was 58 (13) years. Heat maps using 2-dimensional binned plots demonstrated accentuated endothelial cell density results particularly at and immediately above 2500 cells/mm2 with a small gap right under this figure. A bayesian change point analysis revealed a change point at exactly this location as well.

Conclusions and Relevance

Data from this cross-sectional study suggest a discontinuity in endothelial cell-density measurements just below 2500 cells/mm2. This anomaly suggests that the semiautomated counting technique used in this cohort preferentially skipped over measurements just below this cutoff. Whether this represents an automation error, or more likely, a subjective human bias, requires further study.

Comparison of Donor Corneal Endothelial Cell Density Determined by Eye Banks and by a Central Image Analysis Reading Center Using the Same Image Analysis Method

PURPOSE

The purpose of this study was to evaluate agreement between eye banks (EBs) and an image analysis reading center on endothelial cell density (ECD) determinations using the same image analysis method.

METHODS

The Cornea Image Analysis Reading Center (CIARC) determined ECD with a single experienced analyst on EB-obtained central endothelial images from donors intended for keratoplasty from 2 eye banks, Eversight and Lions VisionGift, using the Konan center analysis method. The EBs performed ECD determination on their respective sets of images using the same analysis method with experienced eye bank technicians.

RESULTS

The mean age of the 200 donors was 54 years (range 30-75 years). Seventy (35%) of the 200 patients were women, and 57 (29%) were diabetic. The mean ECD was 10 cells/mm2 greater by the EBs than by CIARC (P = 0.39), with 95% limits of agreement of [-304 to 323 cells/mm2]. The mean difference was not substantially changed when the difference between EBs and CIARC ECD was adjusted for sex, donor age, donor diabetes, CV, HEX, number of cells analyzed, and EBs as a random effect (estimated mean difference of 20 cells/mm2 after adjustment in a linear mixed model; P = 0.73). The EB-determined preoperative ECD was within 10% of the CIARC-determined ECD for 178 (89%) image sets, with 15 (8%) higher by >10% and 7 (3%) lower by >10%.

CONCLUSIONS

Well-trained eye bank technicians achieve comparable results for ECD determination with an experienced image analyst from an image analysis reading center when the same image analysis method is used.

Effect of Body Refrigeration Time on Cornea Donor Tissue

PURPOSE

To determine how early body refrigeration affects corneal donor transplant suitability and endothelial cell density.

METHODS

Donor information was obtained from the CorneaGen Eye Bank including demographics, time of death to preservation, and body refrigeration status, for donors between 2012 and 2016. The death to preservation interval was classified into 3 categories: 0 to 10, 10 to 20, and 20+ hours. Two primary logistic method models were fit using a main effects model and an interaction model to determine the association of body refrigeration on unsuitability of transplantation and endothelial cell density.

RESULTS

Analysis was from 42,929 donor eyes, with a mean (standard deviation) endothelial cell count of 2743 (415) cells/mm2. Fifty-nine percent of donor eyes were from male donors in the eye bank data set, and the mean death to preservation interval was 11.0 (5.6) hours for all eyes. Unsuitability for transplantation demonstrated a reduced adjusted odds ratio by 22% (OR = 0.78, P = 0.009) when the body was refrigerated during the death to preservation interval versus when the body was not refrigerated. Eyes that were refrigerated, however, exhibited no statistically significant difference in endothelial cell count from eyes that were not refrigerated (P = 0.12).

CONCLUSIONS

We demonstrate an appreciable effect of early body refrigeration on transplant suitability in this large cohort of eye bank eyes. There was no beneficial effect of body refrigeration on endothelial cell count.

Analyse von Einflussfaktoren auf die Eignung von kornealem Spendergewebe in der LIONS Hornhautbank Saar-Lor-Lux, Trier/Westpfalz von 2006 bis 2016

Hintergrund und Ziel der Studie Vor dem Hintergrund des Missverhältnisses zwischen Hornhautverfügbarkeit und -bedarf war das Ziel der Studie, signifikante Einflussfaktoren auf die Eignung sowie die Verwerfungsgründe von kornealem Spendergewebe zu eruieren und damit die Rate verworfener Hornhäute langfristig zu reduzieren.

Patienten und Methoden 4140 Hornhäute von 2083 Spendern wurden zwischen 2006 und 2016 analysiert. Die untersuchten Einflussgrößen umfassten das Alter, das Geschlecht und die medizinische Vorgeschichte der Spender und Prozessierungsfaktoren wie die Post-mortem-Zeit. Die Daten wurden in eine Microsoft-Access-Datenbank übertragen und mittels logistischer Regressionsanalysen mit SPSS 20.0 statistisch ausgewertet. In einem multiplen Regressionsmodell wurden 6 Einflussfaktoren auf die Eignung des Spendergewebes analysiert. Alle Hornhäute, die nicht für eine elektive Keratoplastik infrage kamen, galten hierbei als ungeeignet.

Ergebnisse Ein hohes Spenderalter > 80 Jahre erwies sich im Vergleich zur Referenzgruppe der Spender < 40 Jahre als signifikant negative Einflussgröße auf die Eignung der Hornhaut (p = 0,001). Auch eine vorangegangene Kataraktoperation minderte signifikant die Eignung (p < 0,001). Männliche Hornhäute waren signifikant weniger geeignet als weibliche Hornhäute (p = 0,028). Ein Hypertonus in der Spendervorgeschichte (p = 0,612), eine vorangegangene Chemotherapie (p = 0,745) oder ein Diabetes mellitus (p = 0,321) zeigten keinen Einfluss auf die Eignung. Sepsis (p = 0,026) und Multiorganversagen (MOV; p < 0,001) als Todesursachen des Spenders resultierten in signifikant höheren Verwerfungsraten aufgrund von Kontamination des Kulturmediums. Hornhäute, bei denen die Blutentnahme mehr als 12 h seit Versterben des Spenders zurücklag, mussten signifikant häufiger wegen einer positiven Spenderserologie verworfen werden (p < 0,001).

Schlussfolgerungen Faktoren wie eine vorangegangene Kataraktoperation und ein hohes Spenderalter verringerten die Eignung des Spendergewebes. Ein Diabetes, ein Hypertonus und eine Chemotherapie in der Spendervorgeschichte zeigten keinen statistisch signifikanten Einfluss auf die Eignung. Todesursachen wie Sepsis und Multiorganversagen erhöhten die Kontaminationsrate des Kulturmediums. Eine postmortale Blutentnahme nach mehr als 12 h geht mit einem erhöhten Risiko für ein positives Serologieergebnis einher.

Long noncoding RNA KCNQ1OT1 induces pyroptosis in diabetic corneal endothelial keratopathy

Diabetic corneal endothelial keratopathy is an intractable ocular complication characterized by corneal edema and endothelial decompensation, which seriously threaten vision. It has been suggested that diabetes is associated with pyroptosis, a type of programmed cell death via the activation of inflammation. Long noncoding RNA KCNQ1OT1 is commonly associated with various pathophysiological mechanisms of diabetic complications, including diabetic cardiomyopathy and diabetic retinopathy. However, whether KCNQ1OT1 is capable of regulating pyroptosis and participates in the pathogenesis of diabetic corneal endothelial keratopathy remains unknown. The aim of this study was to investigate the mechanisms of KCNQ1OT1 in diabetic corneal endothelial keratopathy. Here, we reveal that KCNQ1OT1 and pyroptosis can be triggered in diabetic human and rat corneal endothelium, along with the high glucose-treated corneal endothelial cells. However, miR-214 expression was substantially decreased in vivo and in experiments with cultured cells. LDH assay was also used to verify the existence of pyroptosis in high glucose-treated cells. Bioinformatics prediction and luciferase assays showed that KCNQ1OT1 may function as a competing endogenous RNA binding miR-214 to regulate the expression of caspase-1. To further analyze the KCNQ1OT1-mediated mechanism, miR-214 mimic and inhibitor were introduced into the high glucose-treated corneal endothelial cells. The results showed that upregulation of miR-214 attenuated pyroptosis; conversely, knockdown of miR-214 promoted it. In addition, KCNQ1OT1 knockdown by a small interfering RNA decreased pyroptosis factors expressions but enhanced miR-214 expression in corneal endothelial cells. To understand the signaling mechanisms underlying the prepyroptotic properties of KCNQ1OT1, si-KCNQ1OT1 was cotransfected with or without miR-214 inhibitor. The results showed that pyroptosis was repressed after silencing KCNQ1OT1 but was reversed by cotransfection with miR-214 inhibitor, suggesting that KCNQ1OT1 mediated pyroptosis induced by high glucose via targeting miR-214. Therefore, the KCNQ1OT1/miR-214/caspase-1 signaling pathway represents a new mechanism of diabetic corneal endothelial keratopathy progression, and KCNQ1OT1 could potentially be a novel therapeutic target.

Validity of Postmortem Glycated Hemoglobin to Determine Status of Diabetes Mellitus in Corneal Donors

PURPOSE

To examine the stability of postmortem glycated hemoglobin (HbA1c) measurement and its relationship to premortem glycemia.

METHODS

Postmortem blood samples were obtained from 32 donors (8 known diabetic) and shipped on ice to a central laboratory to examine the stability of HbA1c measurements during the first 9 postmortem days. Thirty-nine other suspected diabetic donors underwent comparison of premortem and postmortem HbA1c measurements.

RESULTS

Postmortem HbA1c measurements remained stable after 9 postmortem days (all measurements within ±0.2% from baseline with a mean difference of 0.02% ± 0.10%). Of the premortem measurements obtained within 90 days before death, 79% were within ±1.0% of the postmortem measurements compared with 40% for measurements more than 90 days apart. Three of the postmortem HbA1c measurements exceeded 6.5% (considered a threshold for diabetes diagnosis), although the medical histories did not indicate any previous diabetes diagnosis.

CONCLUSIONS

Postmortem HbA1c testing is feasible with current eye bank procedures and is reflective of glycemic control of donors during 90 days before death. HbA1c testing could potentially be a useful adjunct to review of the medical history and records for donor assessment for endothelial keratoplasty suitability and long-term graft success.

The Effect of Chronic Pulmonary Disease and Mechanical Ventilation on Corneal Donor Endothelial Cell Density and Transplant Suitability

PURPOSE

To determine how chronic obstructive pulmonary disease (COPD) and mechanical ventilation time affect corneal donor endothelial cell density (ECD) and transplant suitability.

DESIGN

Retrospective cohort study.

METHODS

Setting: Institutional.

STUDY POPULATION

Total of 39 679 cornea donor eyes from SightLife Eye Bank between 2012 and 2016. Demographics, death-to-preservation time, ECD, lens status, medical history, time on mechanical ventilation, and suitability for transplantation were included.

MAIN OUTCOME MEASURES

ECD and transplant suitability.

RESULTS

Mean ECD was 2733 cells/mm². Mean age was 59 years. COPD affected 34.2% of donors. Mechanical ventilation was required in 35% of donors. Mean ventilation time was 1.3 days. After controlling for covariates, COPD was not found to be associated with poor transplant suitability (P = .22). Ventilation >7 days was associated with poor transplant suitability (P = .04). Donors with COPD and donors who were mechanically ventilated exhibited lower cell counts (P < .001, P < .01, respectively). Longer ventilation led to reduced endothelial cell density: ventilation time >7 days (-46.5 cells/mm², P < .001) and >30 days (-101.4 cells/mm², P = .02). Limitations of the study included the retrospective nature, dataset obtained from a single eye bank, and medical history documentation completed by eye bank technicians.

CONCLUSIONS

A high proportion of cornea donors have respiratory disease prior to donation. Ventilation time >7 days affected transplant suitability but the presence of COPD did not. Donors with COPD and donors who were mechanically ventilated had reduced cell counts. Longer ventilation times lead to increased cell loss. The presence of respiratory disease may affect tissue oxygenation and endothelial cell health.