Abstract
Purpose :
Posterior capsular opacification (PCO) is the leading long-term complication of cataract surgery caused by the remnant lens epithelial cells (LECs) within the capsular bag. LECs undergo epithelial-to-mesenchymal (EMT) transition and acquire a myofibroblast phenotype, further depositing extracellular matrix, such as fibronectin (FN), leading to opacities. Duration of IOL implant, patient comorbidities, and IOL type may be contributing factors to PCO. The aim of this study is to histopathologically analyze EMT and FN expression, and determine the factors that correlate with these changes.
Methods :
In total, one hundred and nighty capsular bags with implanted IOLs were removed from formalin-fixed post-mortem eyes (Minnesota Eye Bank). Clinical history and IOL type were available. Digital images with the Olympus DSX 110 microscope were obtained and PCO was graded using previously published automated software (ADOS, Medical Parachute). After specimens were paraffin-embedded, automated immunohistochemistry with the Ventana Benchmark platform was performed using anti-Smooth Muscle Actin (SMA) to detect EMT, and anti-FN. Slides were digitized using the Aperio ScanScope Scanner, and analysed using the Positive Pixel Count v9 algorithm. Statistical analysis was performed using Spearman correlation, linear regression and one-way ANOVA; P<0.05 was considered significant.
Results :
IOL implantation time and SMA expression had a significant negative correlation (P<0.0001, r=-0.068, r2=0.274). Patient age and SMA expression were also negatively correlated (P=0.0319, r=-0.271). SMA expression was higher within 4 years of IOL implantation and in younger patients. A significant difference between 5 IOL models and SMA expression (P=0.0380) was observed. Optic edge design and gender did not contribute to FN or SMA expression. No correlation between FN and SMA expression, or with the intensity of PCO, was noted.
Conclusions :
This study demonstrated that EMT changes increase within the first few years after surgery. SMA expression is significantly different according to IOL type, thus indicating that LEC changes depend on the lens biocompatibility. Therefore, by analysing the histopathological composition of PCO using LECs, further insight into the characteristics of IOLs that are important for biocompatibility can be ascertained.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.