Regenerative medicine is a new branch of medicine based on tissue engineering technology. This rapidly developing field of science offers revolutionary treatment strategy aimed at urinary bladder regeneration. Despite many promising announcements of experimental urinary bladder reconstruction, there has been a lack in commercialization of therapies based on current investigations. This is due to numerous obstacles that are slowly being identified and precisely overcome. The goal of this review is to present the current status of research on urinary bladder regeneration and highlight further challenges that need to be gradually addressed. We put an emphasis on expectations of urologists that are awaiting tissue engineering based solutions in clinical practice. This review also presents a detailed characteristic of obstacles on the road to successful urinary bladder regeneration from urological clinician perspective. A defined interdisciplinary approach might help to accelerate planning transitional research tissue engineering focused on urinary tracts. STEM CELLS TRANSLATIONAL MEDICINE 2017;6:2033-2043 SIGNIFICANCE STATEMENTThe goal of this review is to present the current status of research on urinary bladder regeneration and highlight further challenges that need to be gradually addressed. We put an emphasis on expectations of urologists that are awaiting tissue engineering based solutions in clinical practice. This review presents a detailed characteristic of obstacles on the road to successful urinary bladder regeneration from a urological clinician perspective.

Replacement of urinary bladder tissue with functional equivalents remains one of the most challenging problems of reconstructive urology over the last several decades. The gold standard treatment for urinary diversion after radical cystectomy is the ileal conduit or neobladder; however, this technique is associated with numerous complications including electrolyte imbalances, mucus production, and the potential for malignant transformation. Tissue engineering techniques provide the impetus to construct functional bladder substitutes de novo. Within this review, we have thoroughly perused the literature utilizing PubMed in order to identify clinical studies involving bladder reconstruction utilizing tissue engineering methodologies. The idea of urinary bladder regeneration through tissue engineering dates back to the 1950s. Many natural and synthetic biomaterials such as plastic mold, gelatin sponge, Japanese paper, preserved dog bladder, lyophilized human dura, bovine pericardium, small intestinal submucosa, bladder acellular matrix, or composite of collagen and polyglycolic acid were used for urinary bladder regeneration with a wide range of outcomes. Recent progress in the tissue engineering field suggest that in vitro engineered bladder wall substitutes may have expanded clinical applicability in near future but preclinical investigations on large animal models with defective bladders are necessary to optimize the methods of bladder reconstruction by tissue engineering in humans.

ObjectiveDue to the capacity of the amniotic membrane (Am) to support re-epithelisation and inhibit scar formation, Am has a potential to become a considerable asset for reconstructive urology i.e., reconstruction of ureters and urethrae. The application of Am in reconstructive urology is limited due to a poor mechanical characteristic. Am reinforcement with electrospun nanofibers offers a new strategy to improve Am mechanical resistance, without affecting its unique bioactivity profile. This study evaluated biocomposite material composed of Am and nanofibers as a graft for urinary bladder augmentation in a rat model.Material and MethodsSandwich-structured biocomposite material was constructed from frozen Am and covered on both sides with two-layered membranes prepared from electrospun poly-(L-lactide-co-E-caprolactone) (PLCL). Wistar rats underwent hemicystectomy and bladder augmentation with the biocomposite material.ResultsImmunohistohemical analysis (hematoxylin and eosin [H&E], anti-smoothelin and Masson’s trichrome staining [TRI]) revealed effective regeneration of the urothelial and smooth muscle layers. Anti-smoothelin staining confirmed the presence of contractile smooth muscle within a new bladder wall. Sandwich-structured biocomposite graft material was designed to regenerate the urinary bladder wall, fulfilling the requirements for normal bladder tension, contraction, elasticity and compliance. Mechanical evaluation of regenerated bladder wall conducted based on Young’s elastic modulus reflected changes in the histological remodeling of the augmented part of the bladder. The structure of the biocomposite material made it possible to deliver an intact Am to the area for regeneration. An unmodified Am surface supported regeneration of the urinary bladder wall and the PLCL membranes did not disturb the regeneration process.ConclusionsAm reinforcement with electrospun nanofibers offers a new strategy to improve Am mechanical resistance without affecting its unique bioactivity profile.

To evaluate the mesenchymal stem cells (MSCs) influence on cytokines and matrix metalloproteinases (MMPs) expression in rat bladder wall regeneration. MSCs cultures from the bone marrow were established. Acellular matrices from the bladder submucosa were prepared. Bladders were reconstructed using cell-seeded (n = 5) and unseeded (n = 5) grafts. MSCs were injected into the bladder wall (n = 5), bladders were incised and MSCs were injected into the circulation (n = 5) or were left intact (n = 5). Animals were killed after 3 months. Bladder histology and immunohistochemical staining of IL-2, IL-4, IL-6, IL-10, TNF-α, TGF-β1, IFN-γ, MMP-2, and MMP-9 were done. Bladders reconstructed with cell-seeded grafts mimicked native tissue, while unseeded grafts revealed shrinkage and morphological irregularities. There were no morphological changes in bladders of other groups. Different pattern of cytokine and MMP expression was observed. Increased expression of anti-inflammatory cytokines and MMPs in bladder promotes detrusor regeneration.

Lung cancer is one of the most common tumors and its treatment is still inefficient. In our previous work we proved that ciprofloxacin has a different influence on five cancer cell lines. Here, we aimed to compare the biological effect of ciprofloxacin on cell lines representing different responses after treatment, thus A549 was chosen as a sensitive model, C6 and B16 as highly resistant. Three different cell lines were analyzed (A549, B16 and C6). The characterization of continuous cell growth was analyzed with the Real-Time Cell Analyzer (RTCA)-DP system. Cytoskeletal changes were demonstrated using immunofluorescence. The cell cycle was analyzed using flow cytometry. Ciprofloxacin was cytostatic only against the A549 cell line. In the case of other tested cell lines a cytostatic effect was not observed. Cytoskeletal analysis confirms the results obtained with RTCA-DP. A549 cells were inhibited in the G2/M phase suggesting a mechanism related to topoisomerase II inhibition. The biological effects of ciprofloxacin support the hypothesis that this drug can serve as an adjuvant treatment for lung cancer, due to its properties enabling topoisomerase II inhibition.

BackgroundThe tissue engineering of urinary bladder advances rapidly reflecting clinical need for a new kind of therapeutic solution for patients requiring urinary bladder replacement. Majority of the bladder augmentation studies have been performed in small rodent or rabbit models. Insufficient number of studies examining regenerative capacity of tissue-engineered graft in urinary bladder augmentation in a large animal model does not allow for successful translation of this technology to the clinical setting. The aim of this study was to evaluate the role of adipose-derived stem cells (ADSCs) in regeneration of clinically significant urinary bladder wall defect in a large animal model.MethodsADSCs isolated from a superficial abdominal Camper’s fascia were labeled with PKH-26 tracking dye and subsequently seeded into bladder acellular matrix (BAM) grafts. Pigs underwent hemicystectomy followed by augmentation cystoplasty with BAM only (n = 10) or BAM seeded with autologous ADSCs (n = 10). Reconstructed bladders were subjected to macroscopic, histological, immunofluoresence, molecular, and radiological evaluations at 3 months post-augmentation.ResultsSixteen animals (n = 8 for each group) survived the 3-month follow-up without serious complications. Tissue-engineered bladder function was normal without any signs of post-voiding urine residual in bladders and in the upper urinary tracts. ADSCs enhanced regeneration of tissue-engineered urinary bladder but the process was incomplete in the central graft region. Only a small percentage of implanted ADSCs survived and differentiated into smooth muscle and endothelial cells.ConclusionsThe data demonstrate that ADSCs support regeneration of large defects of the urinary bladder wall but the process is incomplete in the central graft region. Stem cells enhance urinary bladder regeneration indirectly through paracrine effect.Electronic supplementary materialThe online version of this article (10.1186/s13287-018-1070-3) contains supplementary material, which is available to authorized users.

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Reconstructive urology is a complex and demanding branch of modern urology.Complicated cases, necessity of microsurgical approach, and constant exposure to urine make urinary reconstruction especially difficult. With impaired healing, excessive scarring, and recurring fibrosis, functional results are still not satisfying.For better, more successful outcomes, a novel tissue engineering technology-based solutions are being gradually investigated. The use of tissue engineering is the most promising strategy to improve results of reconstructive urology procedures due to possibility of designing organ-specific grafts. Moreover, targeted modification of healing environment by stem cells and growth factors is a unique opportunity that might bring reconstructive urology on molecular level. This review defined limitations and problems encountered in reconstructive urology and discussed relevant tissue engineering-based achievements in the field of urethra, urinary bladder, and ureter regeneration. The background justifying tissue engineering approach to urethra, urinary bladder, and ureter reconstruction was discussed. Then, the wide range of experimental methods utilising biomaterials and cell seeding was deliberated to show readers the current tools offered by tissue engineering. At the end, we characterised major challenges that are needed to be addressed before tissue entering would become standard technology in urological departments.