Introduction: Peyronie’s Disease (PD) is a penile connective tissue disorder that affects approximately 10% of men. The collagenous plaques that hallmark the disease can result in penile curvature, painful erections, and/or erectile dysfunction. Intralesional injection of collagenase Clostridium histolyticum is the only FDA approved treatment for PD, however, is no longer available in Canada. The enzyme actinidin has the ability to hydrolyze collagen and fibrinogen. Our preliminary work has evaluated actindin on in vitro cellular PD models. Our objectives are to determine the mechanism by which actinidin can reduce collagen composition of in vitro human PD models and explore the cytotoxicity and gene expression of cells treated with actinidin. Methods: Three human PD tissue groups were isolated for fibroblast cells and cultured using complete media. The cells were plated on a 96-well plate and treated with their respective treatments: media, saline, verapamil, actinidin at 50, 25 and 10 mg/ml for 24 hours. MTT assay, immunofluorescent staining, qPCR and collagen quantification assay were used to examine cellular cytotoxicity, cellular organization/morphology, and gene expression, respectively. Statistical analyses were employed using Python 3 and Prism 10. Results: Actinidin significantly reduced the amount of cellular-bound collagen (P <0.01) in our human PD model. The immunofluorescent staining of smooth muscle actin showed a significant increase of normalized actin stained signal, suggesting possible compromise of the cell membrane of PD cells. Microscopic observation of cellular morphology demonstrated the increases of interstitial space in the actinidin treated group compared to negative control, indicating the alteration of extra cellular matrix. MTT assay demonstrated that high concentration of actinidin reduced cellular viability of the PD cells. Conclusions: Our preliminary study suggests the possible effects of actinidin in breaking down PD plaques by compromising the extracellular matrix, membrane-bound proteins, and the cellular membrane of human PD fibroblasts. An increased level of normalized actin in the high concentration actinidin group acts suggests a compromised plasma membrane and a potential mechanism of action. Further studies will investigate the optimal actinidin concentration that can safely reduce the collagen composition of human PD plaques. In the absence of durable FDA-approved treatments for PD in Canada, this novel option could offer future treatment potential. SOURCE OF Funding: Canadian Urology Association Scholarship Foundation - Canadian Mens Sexual Health Council
