Mathieu Theriault

Understanding the process of corneal endothelial morphological change in vitro.

Corneal endothelial cells often adopt a fibroblastic-like morphology in culture, a process that has been attributed to epithelial- or endothelial-to-mesenchymal transition (EMT or EndMT). Although being extensively studied in other cell types, this transition is less well characterized in the corneal endothelium. Because of their neuroectodermal origin and their in vivo mitotic arrest, corneal endothelial cells represent a particular tissue that deserves more attention. This review article presents the basic principles underlying EMT/EndMT, with emphasis on the current knowledge regarding the corneal endothelium. Furthermore, this review discusses cell culture conditions and major cell signaling pathways that have been identified as EndMT-triggering factors. Finally, it summarizes strategies that have been developed to inhibit EndMT in corneal endothelial cell culture. The review of current studies on corneal and classical EndMT highlights some research avenues to pursue in the future and underscores the need to extend our knowledge of this process in order to optimize usage of these cells in regenerative medicine.

In Vivo Functionality of a Corneal Endothelium Transplanted by Cell-Injection Therapy in a Feline Model

Purpose To evaluate the functionality of a corneal endothelium reconstituted by injection of corneal endothelial cells (CEC) in the anterior chamber of a feline model. Methods We operated the right eyes of 16 animals. Eight underwent central endothelial scraping and injection with 2 × 105 (n = 4) or 1 × 106 (n = 4) feline CEC supplemented with Y-27632 and labeled with 3,3′-Dioctadecyl-5,5′-Di(4-Sulfophenyl)Oxacarbocyanine (SP-DiOC18[3] or DiOC). After total endothelial scraping, two eyes were injected with 1 × 106 labeled CEC and Y-27632. The central (n = 3) or entire (n = 3) endothelium was scraped in six eyes followed by Y-27632 injection without CEC. Subjects were positioned eyes down for 3 hours. Outcomes included graft transparency, pachymetry, CEC morphometry, histology, electron microscopy, and function and wound healing–related protein immunostaining. Results Postoperatively, corneas grafted with 2 × 105 CEC and centrally scraped controls displayed the best transparency and pachymetry. Corneas grafted with 1 × 106 CEC yielded intermediate results. Entirely scraped controls remained hazy and thick. Histopathology revealed a confluent endothelial monolayer expressing sodium-potassium adenosine triphosphatase (Na+/K+-ATPase) and zonula occludens-1 (ZO-1) in corneas grafted with 2 × 105 CEC and centrally scraped controls, a nonuniform endothelial multilayer without expression of functional proteins in centrally scraped corneas grafted with 1 × 106 CEC, and a nonfunctional fibrotic endothelium in entirely scraped grafts and controls. Expression of DiOC in grafts was scarce. Conclusions Injected CEC contributed little to the incompletely functional endothelium of grafted corneas. Y-27632 injection without CEC following scraping reconstituted the healthiest endothelium. Further studies investigating the therapeutic effect of Y-27632 alone are needed to validate these conclusions.

Paléo: a collaborative system for social conciliation

Québec Citys Saint-Roch District (Canada) is going through an urban and social transformation period. Over the years, the various efforts aimed at revitalizing the district contributed to the creation of a significant divide between the different social classes. The solution we devised, Paléo, is a social impact outdoor interface aiming to bring together the people frequenting the district. By placing users in a collaborative situation toward a common goal, the search for warmth during the cold Québec winter, our system intends to stimulate the evolution of reciprocal perceptions, and thus, improve the quality of the experience in the district.