# Precision‐Cut Bladder Slices: A Novel Model for the Study of Bladder Fibrosis and Potential Anti‐Fibrotic Agents

## TL;DR

This paper introduces a new method using precision-cut bladder slices to study bladder fibrosis and test potential treatments.

## Contribution

The first use of human precision-cut bladder slices to model fibrosis and screen anti-fibrotic agents is presented.

## Key findings

- PCBS remained viable for 48 hours with stable ATP levels, suitable for ex vivo studies.
- TGF-β stimulation increased fibrosis markers COL1A1 and CCN2, confirming fibrotic response.
- PFD, IMA, and GAL reduced TGF-β-induced fibrosis markers, showing anti-fibrotic potential.

## Abstract

Precision‐cut tissue slice culture is an innovative ex vivo approach for studying fibrosis pathogenesis. Here, we report for the first time the use of human precision‐cut bladder slices (PCBS) to investigate fibrotic changes and evaluate anti‐fibrotic compounds.

Fresh bladder tissue was obtained from 16 patients undergoing surgery for non‐fibrotic conditions and 7 patients with documented bladder fibrosis. PCBS were cultured and stimulated with transforming growth factor β (TGF‐β) to induce fibrotic changes. Viability was assessed by ATP quantification. The anti‐fibrotic efficacy of pirfenidone (PFD), relaxin‐2 (RLN), bone morphogenetic protein 7 (BMP‐7), imatinib (IMA), and galunisertib (GAL) was evaluated. Fibrosis was quantified using qPCR analysis of collagen 1 (COL1A1), fibronectin (FN1), and cellular communication network factor 2 (CCN2) gene expression.

PCBS remained viable over 48 h, with stable ATP levels. TGF‐β stimulation significantly increased COL1A1 and CCN2 expression, confirming induction of a fibrotic response. Treatment with PFD, IMA, and GAL effectively attenuated TGF‐β‐induced upregulation of fibrosis markers. At baseline, PCBS derived from fibrotic bladders exhibited elevated COL1A1 expression compared to non‐fibrotic tissue, while FN and CCN2 levels remained unchanged. PFD treatment notably reduced CCN2 expression in fibrotic PCBS.

This study demonstrates that PCBS provide a viable and reproducible platform for modeling bladder fibrosis and screening anti‐fibrotic therapies. PFD, IMA, and GAL showed promising anti‐fibrotic effects, supporting further investigation into their therapeutic potential.