Combined in vitro and ex-vivo model to design novel combinatorial strategies for the modulation of scarring

Tissue contraction and scarring processes play a part in the cause or failure of treatment of virtually every major blinding disease including glaucoma, cataract, macular degeneration, and diabetes. Everyone over 60 will be affected in part by one of these conditions.Our recently completed Medical Research Council trial of glaucoma surgery has shown that in patients whose ocular scarring is well controlled, not one patient got worse over nearly a decade. There are no licenced treaments for skin and other scarring which is also a big problem. The current used anti-scarring treatments are primarily anti-cancer drugs, which may have potentially blinding side effects, and our research has shown that the models currently available to study tissue contraction and identify new promising treatments are not mimicking accurately what happens in humans. Our work in the lab has identified two previously unknown phases in tissue contraction, suggesting that better treatments should include combinations of treatments targeting both phases of the contraction process. Such an approach has been very successful in cancer chemotherapy, where single agents result in a low success rate but combinations of agents have led to some cancers being curable in the majority of cases. This project aims at further developing and validating our 2-phase model of tissue scarring using both cells and intact ocular tissue fragments maintained in culture in the lab. This project will not only generate tremendous insights into the mechanisms of contraction in the eye, but should provide us with a novel more physiologically relevant tissue contraction model to design novel strategies to modulate scarring, that could directly benefit patients in the short term. This should allow us a more rational approach to devise new treatment combinations for preventing scarring, as well as limiting the amount of animal work required before we can use these treatments to help people and prevent blinding and disabling scarring.

Tissue contraction and scarring processes play a part in the pathogenesis or failure of treatment of virtually every major blinding disease, and indeed our recently completed MRC trial of glaucoma surgery has shown that if scarring is well controlled no patient progressed over nearly a decade. Using a basic in vitro model of matrix contraction combined with an in vivo model of scarring in the rabbit, our lab has been previously successful in identifying anti-mitotic agents as potential modulators of scarring and in bringing them to the clinic. However, these treatments carry significant and potentially blinding side effects. Furthermore, the disappointing results in early clinical trials of a promising novel anti-scarring agent developed through the same models, as well as our most recent work on the basic biology of the in vitro model, suggest the need for better, more comprehensive models for the study of tissue contraction and scarring and the development of potential treatments. We have now uncovered two previously unknown distinct phases in tissue contraction, and shown that both of them need to be inactivated to achieve complete inhibition of matrix contraction. Cell protrusive activity through acto-myosin dynamics mediates the first phase of contraction, while matrix degradation and remodelling through matrix metalloproteinase (MMP) activity are responsible for the second phase of contraction. In parallel, we have started to develop a novel ex-vivo model of conjunctival tissue contraction, which completes and extends our 2-phase in vitro contraction model by using an intact tissue. The purpose of this project is to develop and validate these 2 new models as a more comprehensive an rationale approach to identify novel combinatorial strategies (i.e. targeting phase 1 and phase 2 of the contraction process) for the prevention and treatment of scarring.