Tissue engineering of the urethra: where are we in 2019?

Abstract

Purpose The purpose of this review is to assess the potential role of tissue engineering for urethral reconstruction. It is well-recognised that urethrotomy remains the first-line therapy in the treatment of urethral stricture. Following on from the randomised study which recommended no difference between urethrotomy and urethral dilation, Steenkamp et al. reported long-term success rates of only 20%. Patients with longer strictures, penile or distal urethral strictures, and extensive periurethral spongiofibrosis typically do not respond well to repeated incisions. This report reviews the potential role of tissue engineering as applied to augmentation urethroplasty, which is the treatment of choice following failed urethrotomy. Methods A review of the literature was carried out. The principal emphasis was on tissue engineering as applied to augmentation urethroplasty, but an introductory section reviews the use of urethrotomy and the background to contemporary practise with augmentation urethroplasty using oral mucosa. Results It is evident that a cellular matrix which requires the ingrowth of cells is unlikely to be successful except for very short strictures. Other approaches such as injection of stem cells have not been adequately trialled in humans to date. Tissueengineered substitute for autologous oral mucosa has been used and the results relating to this are reviewed. Conclusions Tissue engineering of autologous tissue for urethroplasty is expensive. It is unnecessary for the majority of cases, but could be potentially useful for very lengthy strictures, for instance, relating to lichen sclerosis. Whilst tissueengineered oral mucosa has been successfully used, a great deal more work would be necessary to develop an appropriate matrix. Another study has looked at a larger series using an alternative tissue-engineered substitute, but the results have been very disappointing. At present, it has to be concluded that there is no effective and validated tissue engineering solution for the management of urethral stricture disease.

Successful engraftment of epithelial cells derived from autologous rabbit buccal mucosal tissue, encapsulated in a polymer scaffold in a rabbit model of a urethral stricture, transplanted using the transurethral approach

“…Tissue engineering is considered an alternative for buccal mucosal substitution urethroplasty for urethral reconstruction [ 3 ]. Some tissue-engineering approaches have been reported in earlier research.…”

“…The complication rate is 12.5%, especially during penile urethroplasty, and urinary fistula, graft contracture and graft failure are common hurdles [ 2 ]. Novel potential treatment options include regenerative approaches, especially cell therapy-based approaches [ 2 , 3 ]. Minced buccal mucosal graft urethroplasty has been earlier reported [ 2 ] in this regard.…”

A Scarless Healing Tale: Comparing Homeostasis and Wound Healing of Oral Mucosa With Skin and Oesophagus

“…This study inspires the use of other tissues for skin regeneration. Oral mucosal cells present advantages over skin cells in therapeutic applications due to their unique scarless properties and are an easy source to harvest reducing time for surgical procedures and accelerating patient’s recovery time ( Izumi et al, 2015 ; Chapple, 2020 ). However, the direct use of mucosal grafts comes with various disadvantages associated with availability of sufficient amount of donor tissue as well as other graft-associated problems, such as donor site morbidity, recipient site, pain and risk of infection ( Llames et al, 2014 ).…”

Experimental study of tissue-engineered urethra with collagen / chitosan composite as scaffolds

“…It is The copyright holder for this preprint this version posted April 30, 2020. ; https://doi.org/10.1101/2020.04.30.070284 doi: bioRxiv preprint 4 extracellular matrix. The potential benefit of tissue engineering over the harvesting of autologous tissue is not needing to harvest the tissue, particularly when long lengths of urethra need to be augmented [6].…”