Bladder Organoids and Spheroids: Potential Tools for Normal and Diseased Tissue Modelling

Bladder-related diseases are among the most common and costly to the healthcare system, and therefore require new approaches to treatment. Organoids and spheroids are 3D cultures that mimic organ features ex vivo and offer novel approaches for diagnostic and therapeutic assessment. The aim of this article was to provide a systematic review of the literature related to bladder organoids and spheroids, applied to disease diagnosis, characterization, and treatment. PubMed and Web of Science were utilized in March 2018 to compile 191 articles satisfying search criteria related to bladder organoids or spheroids and 58 articles were included in the final review. Finally, cell types and techniques utilized for spheroid and organoid manufacture were characterized. The applications of bladder carcinoma spheroids and organoids followed three themes: cancer characterization, diagnosis, and treatment. Tumor characterization studies included a focus on extracellular matrix, microenvironment, genetics, and growth of tumor cells. Diagnostic studies explored the use of endogenous fluorophores and white light for photodiagnosis. Treatment studies investigated cancer chemotherapy, immunotherapy, oncolytic viruses, and gene therapy. Ten studies explored hypericin as a tool for diagnostics and photodynamic therapy. Additionally, two studies applied organoids to urinary tract infections.