Cultured differentiated human urothelial cells in the biomaterials field

An update on alternative therapy for Escherichia coli causing urinary tract infections; a narrative review

BACKGROUND

Urinary tract infections (UTIs) are the most common type of nosocomial infection and severe health issues because of the difficulties and frequent recurrence. Today, alternative methods such as sonodynamic therapy (SDT), photodynamic therapy (PDT) and herbal materials use for treating infections like UTI in many countries.

METHOD

We conducted searches of the biomedical databases (Google Scholar, Scopus, PubMed, and Web of sciences) to identify related studies from 2008 to 2023.

RESULT

SDT aims to use ultrasound to activate a sonosensitizer, which causes a biological effect by raising reactive oxygen species (ROS). When bacteria are exposed to ROS, several important effects occur: oxidative damage, DNA damage, protein dysfunction etc. SDT with herbal medicine significantly reduced the number of colony-forming units and bactericidal activity for Klebsiella pneumonia and E. coli. PDT is a promising treatment for cancer and microbial infections, combining a photosensitiser, light and tissue molecular oxygen. It involves a photosensitizer, light source, and oxygen, with variations affecting microbial binding and bactericidal activity. Factors affecting antibacterial properties include plant type, growing conditions, harvesting, and processing. This review highlights the recent advancements in sonodynamic, photodynamic, herbal, and bio-material-based approaches in the treatment of E. coli infections.

CONCLUSIONS

These alternative therapies offer exciting prospects for addressing UTIs, especially in cases where traditional antibiotic treatments may be less effective. Further research and clinical studies are warranted to fully explore the potential of these innovative treatment modalities in combating UTIs and improving patient outcomes.

What's in the Pipeline about Bladder Reconstructive Surgery? Some Remarks on the State of the Art

The fusion of engineering with cell biology and advances in biomaterials may lead to de novo construction of implantable organs. Engineering of neobladder from autologous urothelial and smooth muscle cells cultured on biocompatible, either synthetic or naturally-derived substrates, is now feasible in preclinical studies and may have clinical applicability in the near future. The development of a bioartificial bladder would warrant the prevention of both the metabolic and neoplastic shortcomings of the intestinal neobladder. Two tissue-engineering techniques for bladder reconstruction have been tested on animals: 1) the in vivo technique involves the use of naturally-derived biomaterials for functional native bladder regeneration 2) the in vitro technique involves the establishment of autologous urothelial and smooth muscle cell culture from the host's urinary tract, after which the cells are seeded on the biodegradable matrix-scaffold to create a composite graft that is implanted into the same host for complete histotectonic regeneration. Waiting for the creation of a complete tissue-engineered bladder with a trigone-shaped base, we suggest, in surgical oncology after radical cystectomy, the realization of conduit or continent pouch using tissue-engineered material.

Is there room for luminal-basal urothelial cell population quantification?

PURPOSE

Three cell layers compose the urothelium: basal, intermediate and luminal ("umbrella cells") and different diseases might arise from different cell populations. The aim of this study is to analyze the quantification ability of such cell populations by using four different protocols.

METHODS

Twenty male rats (Wistar) were randomized in four groups of five animals: scraping, enzymatic 30, 45 and 60minutes. The cells were isolated, analyzed by flow cytometer and data processed by BD FACSDIVA™ software.

RESULTS

The urothelium was separated in two cell populations that are different in size and complexity. The group that showed more efficiency in cells dissociation and cells separation was enzymatic protocol 45minutes.

CONCLUSIONS

Enzymatic protocol 45minutes was able to isolate urothelial cell populations and might be explored as potential prognostic tool, patient selection and therapeutic target in urothelial diseases. Future studies should validate the potential clinical application to the proposed rational of luminal-basal paradigm in the urothelial cancer as hope for individualized approach.

How to isolate urothelial cells? Comparison of four different methods and literature review

The aim of this study is to present the comparison of four different methods for urothelial cell isolation and culture and compare them to methods cited in the literature. Four different techniques were examined for urothelium isolation from rat bladders. Isolation effectiveness was calculated using trypan blue assay. Confirmation of isolated cell phenotype and comparison with native bladder tissue was confirmed using immunohistochemical (IHC), immunocytochemical (ICC) and immunofluorescence (IF) analysis. The method with bladder inversion and collagenase P digestion resulted in the highest number of isolated cells. These cells showed positive expression of cytokeratin 7, 8, 18, α6-integrin and p63. Our results and the literature review showed that the best method for urothelium bladder isolation is dissection of the epithelium layer from other bladder parts and digestion of mechanically prepared tissue in a collagenase solution.

Air-liquid and liquid-liquid interfaces influence the formation of the urothelial permeability barrier in vitro

Optimizing culture conditions is known to be crucial for the differentiation of urothelial cell cultures and the formation of the permeability barrier. However, so far, no data exist to confirm if air-liquid (AL) and liquid-liquid (LL) interfaces are physiologically relevant during urothelial differentiation and barrier formation. To reveal the influence of interfaces on the proliferation, differentiation, and barrier formation of the urothelial cells (UCs) in vitro, we cultured UCs under four different conditions, i.e., at the AL or LL interfaces with physiological calcium concentration and without serum or without physiological calcium concentration and with serum. For each of the four models, the urothelial integrity was tested by measuring the transepithelial resistance (TER), and the differentiation stage was examined by immunolabeling of differentiation-related markers and ultrastructural analysis. We found that the UCs at a LL interface, regardless of the presence or absence of calcium or serum, form the urothelium with more cell layers and achieve a higher TER than UCs at an AL interface. However, UCs grown at an AL interface with physiological concentration of calcium in medium form only one- to two-layered urothelium of UCs, which are larger and express more differentiation-related proteins uroplakins than UCs in other models. These results demonstrate that the interface itself can play a major, although so-far neglected, role in urothelial physiology, particularly in the formation of the urothelial permeability barrier in vitro and the regulatory mechanisms related with urothelial differentiation. In the study, the culturing of UCs in three successive steps is proposed.

Altered phenotype of cultured urothelial and other stratified epithelial cells: implications for wound healing

The differentiation of cultured stratified epithelial cells can deviate significantly from that of normal epithelium, leading to suggestions that cultured cells undergo abnormal differentiation, or a truncated differentiation. Thus cultured epidermal and corneal epithelial cells stop synthesizing their tissue-specific keratin pair K1/K10 and K3/K12, respectively. The replacement of these keratins in the suprabasal compartment by K6/K16 keratins that are made by all stratified squamous epithelia during hyperplasia rules out a truncated differentiation. Importantly, the keratin pattern of in vivo corneal epithelium undergoing wound repair mimics that of cultured rabbit corneal epithelial cells. Although cultured urothelial cells continue to synthesize uroplakins, which normally form two-dimensional crystalline urothelial plaques covering almost the entire apical urothelial surface, these proteins do not assemble into crystals in cultured cells. Cultured epithelial cells can, however, rapidly regain normal differentiation on the removal of mitogenic stimuli, the use of a suitable extracellular matrix, or the transplantation of the cells to an in vivo, nonmitogenic environment. These data suggest that cultured epithelial cells adopt altered differentiation patterns mimicking in vivo regenerating or hyperplastic epithelia. Blocking the synthesis of tissue-specific differentiation products, such as the K1 and K10 keratins designed to form extensive disulfide cross-links in cornified cells, or the assembly of uroplakin plaques allows epithelial cells to better migrate and proliferate, activities that are of overriding importance during wound repair. Cultured urothelial and other stratified epithelial cells provide excellent models for studying the regulation of the synthesis and assembly of differentiation products, a key cellular process during epithelial wound repair.

[Experimental study about viability of autologous free graft in vitro cultivated urinary epithelium]

OBJECTIVE

The purpose of this study is to apply the in vitro keratinocyte culture techniques and the tissue engineering principles to urothelium, to obtain a three-dimensional autologous tissue suitable for grafting. We also showed the viability of free graft cultured urothelium in an experimental model.

MATERIAL AND METHODS

An animal experimental model was designed to apply the techniques of cellular culture and tissue engineering. Biopsy specimens of bladder mucosa were obtained, in vitro cultured and posteriorly implanted in each animal. We established three groups based on different follow-up periods (7, 14 and 30 days), and made a final histomorphological study to demonstrate the viability of the graft at the end of its respective follow-up period.

RESULTS

A three-dimensional in vitro tissue was obtained, composed of a bio-artificial submucosa (fibrin gel and fibroblast) where the uroepithelial cells were seeding; a biodegradable polyglycolic acid mesh was used to facilitate the tissue manipulation and implantation. In the morphological study all the implants appeared viable, but the grafts with longer implantations periods were better conformed, showing a tisular structure with multiple cellular layers.

CONCLUSIONS

In vitro keratinocyte culture techniques could be applied to other epithelial tissues as the urothelium. We obtained a three-dimensional in vitro tissue suitable for grafting in a relatively short time. The histological study demonstrated that free autologous urothelial graft is totally viable, opening future clinics applications.

In vitro biocompatibility assessment of naturally derived and synthetic biomaterials using normal human urothelial cells

The reconstruction of urinary tissues often employs various types of biomaterials, and adequate material biocompatibility is essential for the successful reconstruction of urinary tissues. In this study we utilized a primary normal human urothelial cell culture system to evaluate the in vitro biocompatibility of a number of naturally derived biomaterials [i.e., bladder submucosa, small intestinal submucosa, collagen, and alginate] and polymeric biomaterials [i.e., poly(glycolic acid), poly(L-lactic acid), poly(lactic-co-glycolic acid), and silicone] that are either experimentally or clinically used in urinary reconstructive surgery. To determine the cytotoxic and bioactive effects of these biomaterials, the cell viability, metabolic activity, apoptotic properties, and DNA-synthesis activity were measured with four types of assays [Neutral Red, 3-(4,5-dimethylthiazol-2-yl)-2,5diphenyl tetrazolium bromide, apoptotic activity, and tritiated thymidine incorporation assays] using extract and direct contact methods. Most of the biomaterials tested did not induce significant cytotoxic effects and exhibited normal metabolic function and cell growth in vitro. This normal primary human urothelial cell culture model is suitable for in vitro biocompatibility assessments and is able to provide information on the cell-biomaterial interactions and the ability of biomaterials to support bioactive cell functions.