Acetylsalicylic acid reduces collagen contraction, remodelling and myofibroblast proliferation in Tenon's Capsule tissue mimetic

Authors: James J. Armstrong, Cindy M. L. Hutnik 
Author Disclosure Block: J.J. Armstrong: None. C.M.L. Hutnik: None.

Purpose: Glaucoma surgery outcomes, traditional as well as MIGS, are hindered by inflammation-driven excessive wound healing responses. As such, perioperative corticosteroids are often used as a means to control preexisting and/or surgically induced inflammation. NSAIDs are used to a lesser extent in glaucoma surgery, however are ubiquitous in cataract surgery. The more specific nature of COX1/2 inhibition by NSAIDs allows fewer unwanted side effects, such as steroid associated intraocular pressure (IOP) spikes. Long duration of action is beneficial for topically applied medications, as such, we assessed the efficacy of irreversible COX-1/2 inhibitor - acetylsalicylic acid (ASA) - to prevent collagen contraction, remodeling and myofibroblast proliferation in vitro. 

Study Design: In vitro 3D cell/tissue culture 

Methods: Human Tenon’s capsule fibroblasts (HTCFs) were cultured within both restrained and unrestrained collagen matrices that were augmented with HTCF secretory proteins. In the unrestrained, contraction was measured hourly for 12hr, then daily for 4 days. After which total RNA was extracted for gene expression analysis. The restrained matrices were allowed to mature under self-imposed tension for 7 days, then fixed and sectioned for histological analysis. 

Results: At all time points, contraction was significantly reduced by ASA (0.02%) compared to control (p < 0.001). This effect was dramatically increased by gentamicin (0.01%), such that combination treatment resulted in no contraction (p < 0.001). Expression of Col3A1, Col2A1 and ACTA2 were all significantly decreased compared to control (p < 0.01). Restrained matrices treated with ASA displayed significantly smaller, less dense staining collagen fibers compared to control (p < 0.01). Immunostaining for alpha smooth muscle actin and Ki67, indicating proliferating myofibroblasts, was increased in control sections versus those treated with ASA. TUNEL staining revealed comparable rates of cell death across treatment groups (p > 0.05). 

Conclusions: The results of this study demonstrate acetylsalicylic acid as a candidate drug for perioperative inflammation control and wound healing modulation in glaucoma filtration surgery.