In vitro study of the generation of anterior subcapsular opacity after mechanical stimuli

Abstract

Purpose : Lens epithelial cells undergo epithelial to mesenchymal transition (EMT) after injury, resulting in the generation of myofibroblasts and tissue fibrosis in the lens. This process is comparable to the maturation process of a cataract and also to the postoperative features on the anterior capsule after cataract surgery.
In some cases, literature suggests the possibility of an anterior subcapsular cataract after Implantable Collamer Lens (ICL) implantation. This effect is associated with the contact of the ICL with the crystalline lens, especially in older patients and patients with a narrow anterior chamber. The aim of this work is to study the generation of anterior subcapsular opacity in the lens after mechanical stimuli.

Methods : Anterior lens capsules were obtained from cataract surgeries and from healthy donors from the Community Center for Blood and Tissues - CCST.
An explant culture model was performed using the total tissue collected in surgery, usually a 6 mm in diameter disc of the anterior capsule of the lens, containing the anterior subcapsular epithelium.
One group of cultures was exposed to mechanical contact with an sterile ICL with cicles of 2 hours for one week. Control cultures were maintained in normal conditions. Selected cultures from each group were treated with SIS3 inhibitor or with Rapamycin.
The molecular phenotype of the cells in culture was evaluated by means of immunocytochemical techniques in the different phases. Epithelial markers, such as E-Cadherin or β-Catenin, was used, as well as mesenchymal and fibroblast cell markers such as vimentin or smooth muscle actin (α-SMA).

Results : Capsular epithelial cells maintain epithelial morphology and biochemistry in culture. These cells presented the ability to spontaneously express markers of contractile cells, such as α-SMA or vimentin. Expression of α-SMA was increased after mechanical contact with ICL in vitro.
Cultures in which EMT was inhibited showed a lower proportion of SMA cells. Cultures in which ICL contact was interrupted, also exhibited a partial reversion of the fibrotic phenotype.

Conclusions : Contact with implanted collameric lenses in vitro tiggered the signaling of contractile fibers production in anterior subcapsular epithelium. This process was partially reversible by removing contact stress.

This is a 2021 ARVO Annual Meeting abstract.