Integration of collagen matrices into the urethra when implanted as onlay graft

Abstract

Objective: To assess the integration of decellularized heterologous collagen matrices into the urethra, when implanted with no cells or when seeded with autologous smooth muscle cells. Materials and Methods: Eighteen New Zealand rabbits were randomly assigned to two groups: Group I (n = 9) -animals undergoing urethral segment resection with interposition of a patch of heterologous collagen matrix seeded with autologous smooth muscle cells; Group II (n = 9) -animals undergoing resection of a urethral segment with interposition of a decellularized heterologous collagen matrix patch. Two animals from each group were sacrificed on postoperative days seven, fourteen and twenty-eight; three animals from each group were sacrificed at the end of three postoperative months. At the end of the third month one animal from each group underwent urethroscopy for urethral integrity assessment and one animal from each group had its microcirculation image captured by a SDF device (Side-stream Dark Field -Microscan Analysis Software). One animal from each group in each euthanasia period underwent cystourethrography so as the urethra could be viewed at flow time. The matrices integration was assessed through histological examination using hematoxylin and eosin (H&E), Masson trichrome (MT), Picrosirius red and Von Willebrand staining. In a blind study with two pathologists all the slides were studied. Results: The matrices whether seeded or not with autologous muscle cells were able to restore the architecture of the urethra, but were eliminated from the first week on, before incorporation. Microcirculation of the neourethra, at the end of the third month, showed the same characteristics as a normal urethra in both groups of animals. Conclusion: Natural heterologous matrices implanted in the urethra as onlay graft were not incorporated into its walls but were able to fully restore the cell architecture of the organ, regardless of being seeded or not with autologous muscle cells.

Evaluation of the effects of vitamins C and E on experimentalorthodontic tooth movement

“…Therefore, two different slices were obtained to evaluate collagen fibers with Masson's trichrome staining in addition to HE staining in the present study. 31 Consistent with previous studies, our findings showed a significant increase in the number of collagen fibers in the tension area of all the appliance groups. Vitamin C has also been known to be directly related to collagen synthesis in previous experimental studies.…”

Comparison of Poly(l-lactide-co-ɛ-caprolactone) and Poly(trimethylene carbonate) Membranes for Urethral Regeneration: AnIn VitroandIn VivoStudy

“…Normal inflammatory cell appearance was scored as zero; less than 25 % of all cells was scored as one; 25-50 % was scored as two and over 50 % was scored as three. 24 The epithelial integrity and structure and inflammation-related parameters were examined at 40× magnification. Fibrosis was determined from Masson´s trichrome-stained samples and scored.…”

Electrospinning: Application and Prospects for Urologic Tissue Engineering

“…The pre-seeded matrix supported the reconstruction of a wide-caliber urethra without stricture, while the bare matrix failed (Orabi et al, 2013). Contrary to the previous study, the onlay application of bladder submucosa preseeded with autologous SMCs in rabbit did not demonstrate any significant regenerative advantage over the bare matrix, and both of them resulted in fully restored normal architecture of the urethra (Sayeg et al, 2013). In this regard, it has been shown that urine-derived stem cells cultured on SIS held superior capacity for regeneration of urethra.…”

“…Similar to many organs treated by tissue engineering methods, collagen-based naturally derived scaffolds were among the first preferred options for reconstruction of urethra. This is because of the superior biocompatibility of these materials, and their supportive nature for cell attachment, growth, colonization, and remodeling of regenerating tissues (El-Tabey et al, 2012;Orabi et al, 2013;Sayeg et al, 2013;Wang et al, 2014;Liu et al, 2017). El-Tabey et al used a canine acellular bladder matrix, pre-seeded with autologous bladder cells (UCs and SMCs), for urethroplasty of 3 cm segment of the urethra in female dogs, and followed the regeneration process for 11 months.…”