A human slice model to understand the role of fibrosis in children with bladder exstrophy

Bladder exstrophy is a condition in babies where the bladder and front of the abdomen fail to develop properly, which leaves the open bladder exposed on the front of the tummy at birth. Surgery for affected children is only available in Manchester or Great Ormond Street (GOS) in the UK but outcomes are poor, even with the best care in these specialist centres: many are permanently incontinent with frequent urine infections and have sexual dysfunction in later life. The applicant, Mr Johal, leads exstrophy surgery at GOS and has a unique research background with a PHD focussing on normal and abnormal function of the muscles in the bladder. He has shown that most of the expected bladder muscles are replaced by scar tissue in exstrophy. This occurs via a process called fibrosis, which is also implicated in many other conditions; hence there are a number of new drugs being developed to treat fibrosis which have not yet been tested in exstrophy. Part of the abnormal bladder is removed during routine exstrophy surgery, and this will be used by Mr Johal to test whether fibrosis can be stopped (or even reversed) by these drugs, in collaboration with Professor David Long (Institute of Child Health) who has successfully undertaken similar experiments in the kidney. Taken together, Mr Johal's unique background, access to exstrophy samples and drive to improve outcomes combined with support from Professor Long's innovative laboratory team, this is a timely opportunity to increase understanding of bladder exstrophy and test new therapies that may be used clinically in future.

Aims and Objectives: To (i) develop a novel precise cut human bladder slice model to study bladder exstrophy; (ii) use the model to test if two anti-fibrotic soluble guanylate cyclase modulators can prevent the progression of bladder exstrophy; (iii) use single cell RNA-sequencing to identify new molecular targets which could prevent fibrosis in bladder exstrophy. Collectively, this application will also provide me with the dedicated time to establish a program of research in paediatric urology, an area of unmet clinical need.

Methods: Precision-cut slices for culture will be generated from bladder exstrophy samples or age-matched controls. Viability, cell turnover and degree of fibrosis will be evaluated. Using a separate piece from the same biopsy sample a physiological assessment of the bladder will be made by examining contractility and stiffness. The effect of two anti-fibrotic drugs will be assessed. Additionally, new molecular pathways underlying fibrosis in bladder exstrophy will be identified using single-cell RNA-sequencing.

Outcomes: A new non-surgical model will be established for human bladder exstrophy. This model will be used to test the effectiveness of two anti-fibrotic drugs as potential therapies for bladder exstrophy. Non-biased sequencing at a cellular level will identify new treatment direction for bladder exstrophy. By the end of the proposal, I aim to fully embed research alongside my clinical activities and build a basis to support future trainees in urology and basic scientists in bladder physiology and molecular pathology.