Jafari, N. V. | Search bioRxiv

bioRxiv2025

Modelling catheter-associated bladder mucosal adhesion and microtrauma using a human urothelial microtissue model

Animal models have been used to investigate urinary tract catheters, but most do not accurately recapitulate human bladder physiology nor support different types of catheters. Recent advances in three-dimensional models mimicking tissue microenvironments have improved our understanding of human tissue development and allowed us to model many diseases. Here, our objective was to characterise bladder urothelial mucoadhesion and microtrauma associated with intermittent catheterisation. We employed our three- dimensional Urine-tolerant Human Urothelial model (3D-UHU) to investigate two different intermittent catheter types, a polyvinylpyrrolidone (PVP)-coated catheter (PVP-CC), and a coating-free integrated amphiphilic surfactant (IAS) catheter. We showed that pressing catheters onto the models for two minutes caused compression of the 3D-UHU model in contact regions, with disruption of urothelial umbrella cells detected by immunofluorescence staining of surface markers uroplakin III, cytokeratin-20 and chondroitin sulphate, alongside occasional effacement of apical surfaces exposing intermediate layers. PVP-CC had a significantly higher number of urothelial cells adhered to its surface after catheter removal compared with IAS. Moreover, application and removal of PVP-CC caused a decrease in transepithelial electrical resistance, suggesting barrier disruption, whereas IAS did not cause a statistically different effect. However, no change in paracellular permeability rates assessed by FITC-dextran were observed in models after application of catheter pieces. Finally, compression of models induced trauma-triggered inflammatory cytokine responses. Specifically, we observed increased secretion of the pro- inflammatory cytokine IL-1{beta} as well as the cell adhesion molecule CEACAM1 after exposure to PVP-CC compared with IAS. Our findings suggest that the IAS catheter damaged the epithelium less than the PVP-CC catheter. These data demonstrate that the 3D-UHU model holds promise as an alternative to animal models for investigating the effects of urinary catheters on the urothelium.

bioengineering↗

bioRxiv2022

An immunoresponsive three-dimensional urine-tolerant human urothelial (3D-UHU) model to study urinary tract infection

Murine models of urinary tract infection (UTI) have significantly improved our understanding of host-pathogen interactions. However, given some differences between the rodent and human bladder which may modulate bacterial response, including certain biomarkers, urothelial thickness and the concentration of urine, the development of new human-based models is important to complement mouse studies and to provide a more complete picture of UTI in patients. We originally developed a human urothelial three-dimensional (3D) model which was urine tolerant and demonstrated several biomarkers of the urothelium, but it only achieved human thickness in heterogenous, multi-layered zones and did not demonstrate the comprehensive differentiation status needed to achieve barrier function. Here, we report an improved 3D urine-tolerant human urothelial (3D-UHU) model, which after 18-20 days of growth, stratifies uniformly to 7 layers. We confirmed by flow-cytometric analysis that the model is comprised of the three expected, distinct human cell types. The apical surface differentiated into large, CD227+ umbrella-like cells expressing uroplakin-1A, II, III, and cytokeratin 20, all of which are important terminal differentiation markers, and a glycosaminoglycan layer. Below this layer, several layers of intermediate cells were present, with a single underlying layer of CD271+ basal cells. The apical surface also expressed E-cadherin, ZO-1, claudin-1 and -3, necessary for barrier formation; barrier integrity was confirmed by transepithelial electrical resistance and FITC-dextran permeability assay. Infection with both Gram-negative and Gram-positive bacterial classes elicited elevated levels of pro-inflammatory cytokines and chemokines characteristic of urinary tract infection in humans, and caused a decrease in barrier function, suggesting that the 3D-UHU model holds promise for studying host-pathogen interactions and host innate immune response.

microbiology↗