Endothelial Cells Survival in Human Corneal Grafts When Using the Modified Method Treatment of Keratoconus
Authors: Рыков С.А. , Лысенко М.Г. , Шаргородская И.В. , Лаврик Н.С. , Макаренко И.А. , Новак Л.П. , Выдыборец С.В. 
Published: March 2022

Проведена лазерная сканирующая конфокальная микроскопия донорских трупных роговиц, предназначенных для кератопластики. С помощью программного обеспечения ImageJ проанализирована рефлективность эндотелия и введено понятие коэффициента рефлективности эндотелиальных клеток роговицы (КРЭКР). В ходе статистической обработки определены морфометрические свойства эндотелиоцитов при конфокальной микроскопии, которые существенно влияют на потерю эндотелиальных клеток на трансплантате и, возможно, являются признаками апоптоза эндотелиоцитов. Разработана методика вископротекции эндотелия кадаверной роговицы на этапе формирования трансплантата. Отмечено, что сочетание качественной отбраковки донорского роговичного материала по разработанным критериям с проведением интраоперационной вископротекции эндотелия сокращает процент потери эндотелиальных клеток на роговичном трансплантате почти в 4 раза в течение первого года после трансплантации, что является профилактикой развития позднего эндотелиального отторжения роговичного трансплантата. Установлено, что общий (абсолютный и относительный) брак донорских роговиц для проведения сквозной аллокератопластики при кератоконусе составляет приблизительно 60%.

Keratoconus is a disorder of the eye characterized by thinning and protrusion of the cornea, resulting in an irregular, conical shape and is the cause of persistent decline in vision and disability of young able-bodied people. Despite development of lamellar techniques of corneal surgery, penetrating keratoplasty remains the "gold standard" in the keratoconus treatment. The rapid loss of endothelial cells on the corneal graft at 6 months after keratoplasty is an important early symptom of late graft rejection (Lass J.H. et all, 2010). The aim of this study is to improve the quality of preservation ofendothelial cells on the native corneal grafts. This task can be solved by qualitative preliminary selection of donor tissue and reduction of intraoperative traumatization of endothelium on corneal graft.Methods. In Kyiv ophthalmic city hospital "Eye microsurgery center" (Kyiv, Ukraine) determined preoperative endothelium cells density by Heidelberg Retina Tomograph HRT II Rostock Cornea Module and were archived available endothelium cells images (590 human cadaveric corneas). Endothelial cells reflectivity analyses performed by ImageJ free software. Proposed to introduce the concept of the coefficient of reflectivity of corneal endothelial cells. Also noted the presence of organelles and "swelling" endothelial cells.In 1st clinic group (n=57) all the patients got standard penetrating keratoplasty procedure with standardly graft exams. Investigated the dependence of rapid endothelial cells loss with endothelial morphometric properties. In 2nd clinic group (n=29) all the patients got standard penetrating keratoplasty procedure with qualitative screening of corneas with new morphometric criteria (coefficient of corneal endothelial reflectivity more, than 50; without "swelling" endothelial cells and without organelles in the endothelial cells). In 3rd clinic group (n=43) patients got qualitative screening of corneas (like 2nd group), but viscoprotection during "back table" procedure has been developed.Results. As a result, combination of qualitative rejection of cadaveric corneas with morphometric endothelial factors reduces the percentage of cell loss four times. Tree morphometric factors in any combination were related with rapid loss of endothelial cells in graft: coefficient of corneal endothelial reflectivity lower, than 50; "swelling" endothelial cells and organelles in the endothelial cells. Determined that total (absolute and relative) qualitative rejection make unsuitable for penetrating keratoplasty for keratoconus approximately 60% of cadaveric corneas.Discussion. This study may help to reduce endothelial cells loss and frequency of late endothelial rejection of corneal grafts. Tree morphometric factors in any combination were related with rapid loss of endothelial cells in graft: coefficient of corneal endothelial reflectivity lower, than 50; "swelling" endothelial cells and organelles in the endothelial cells. Perhaps, these factors are markers of endothelial cells apoptosis.Conclusion. Investigated the dependence of rapid endothelial cells loss with endothelial morphometric properties. Proposed to introduce the concept of the coefficient of reflectivity of corneal endothelial cells. Proposed the methodology of endothelial viscoprotection during "back table" procedure before penetrating keratoplasty.