Methods to Reduce the Contraction of Tissue-Engineered Buccal Mucosa for Use in Substitution Urethroplasty

Background: We previously described the production and clinical outcomes of tissue-engineered buccal mucosa (TEBM) used to treat recurrent urethral strictures. In this study, two patients developed a recurrent stricture and there was also evidence of graft contraction. Objective: Assess possible preclinical methods to reduce contraction of TEBM. Design, setting and participants: Using the model of TEBM in use clinically (ie, oral keratinocytes and fibroblasts cultured on de-epidermised acellular dermal scaffold), three methods of reducing TEBM contraction were investigated in vitro. Interventions: The techniques assessed were pretreatment of de-epidermised dermis (DED) with glutaraldehyde, culture with beta-aminopropionitrile (beta-APN; a lysyl oxidase inhibitor), and physical restraint of TEBM grafts during culture. Measurements: Contraction was assessed using serial digital image analysis. The cytotoxicity of the pharmacologic manipulations was assessed using monolayer cultures of oral mucosa cells. Results and limitations: Control TEBM lost a mean of 45.4% of its original surface area over 28 d of culture. Treating TEBM with glutaraldehyde, beta-APN, or mechanical restraint during culture all significantly inhibited graft contraction. Glutaraldehyde treatment was most effective (only 5.5% loss of area with 0.1% glutaraldehyde), followed by mechanical restraint for at least 7 d (21.4% loss of area), and then beta-APN (28.7% loss of area). None of the treatments had any significant effect on cell viability. This in vitro study identifies solutions for graft contracture to explore in the clinic. Conclusions: Glutaraldehyde pretreatment and restraint of TEBM grafts during culture both reduce graft contraction. (C) 2011 European Association of Urology. Published by Elsevier B. V. All rights reserved.