Autologous cell engineered bladder augmentation

Some 3 million people in the UK experience incontinence and the cost of management is over £500 million per annum to the NHS. It can be caused by both congenital anomalies, such as a failure of the bladder in the fetus to form (bladder exstrophy), and acquired conditions such as a loss of the compliance of the bladder (neuropathic bladder) or bladder cancer. For end-stage bladder disease, the most commonly performed surgical procedure to augment or replace the bladder involves incorporating a vascularised, reconfigured segment of bowel (enterocystoplasty). Although this procedure can provide continence and enhance quality of life, it is commonly associated with serious complications, including infections, mucus production and stone formation, and a possible long-term risk of cancer. These complications are primarily due to the fact that bowel mucosa is structurally and physiologically incompatible with the long-term exposure to urine. A number of bladder engineering strategies have been proposed and typically, these rely upon the incorporation of a natural or synthetic biomaterial into the bladder, which may or not be pre-cultured with cells derived from the patient (autologous). Despite some high profile reports, there is little evidence that bladder tissue engineering can yet achieve a functional outcome equivalent to current surgical techniques, and there remains an unmet clinical need. The aim of this programme is to deliver functional bladder reconstruction to patients through an autologous cell engineering strategy. This project will bring together expertise in stem cells and urology (ICH, GOSH, Evelina London Children's Hospital) with urothelial cell biology and bladder tissue engineering (University of York) with the purpose of developing a novel technique for bladder reconstruction that will be applicable in the first instance to patients with bladder exstrophy, but eventually extended to any paediatric or adult patient requiring bladder augmentation.
The stages of the project will be to:
1. Prepare a bank of transplant-relevant human epithelial cells for assessment in composite cystoplasty.
2. Transplant human epithelial cells into immunosuppressed pigs using the composite cystoplasty procedure and monitor function for 3 & 6 months before sacrifice. Principal outcome measures will be: safety as measured by survival; efficacy as measured by capacity and compliance of the neo-bladder. Secondary measures for this phase will include: surgical morbidity, post-mortem gross anatomy and immunohistological analysis of both the augmented and native mucosa

1. Sourcing of autologous cells. Bladder mucosa will be harvested from children undergoing bladder
procedures according to ethical approval. Buccal mucosa epithelium will be obtained from discarded
tissue during urethral reconstruction (ethical approval granted). Cells will be isolated and expanded
using established techniques and tested for their capacity to express differentiation-associated
markers and develop functional barrier properties by measuring trans-epithelial electrical resistance
and permeability to urea and water. Human urothelial and buccal epithelial cells will be
produced/banked for transplantation into pigs.
2. The harvest of differentiated sheets and suitable carrier for transport and delivery will be refined.
3. Establish a porcine experimental surgical model of composite cystoplasty. A vascularised, deepithelialized,
seromuscular colonic segment will be developed in a total of 20 immunosuppressed
pigs. After isolation, the patch will receive a tissue-engineered epithelial sheet in association with inert
carrier (Vicryl mesh) to facilitate epithelial sheet transfer and surgical attachment. The pigs will be
divided into 2 groups (10 animals each): one set will receive a bladder augment with a patch built with
tissue derived from healthy urothelium; the second will undergo augmentation using tissue from
buccal mucosal epithelium. The animals will be sacrificed at 6 months post-augment. The assessment
will include voiding behaviour records and post-mortem immunohistological analysis of both the
augmented and native mucosaXenogeneic transplant of human epithelial cells into 20 pigs using the
composite cystoplasty procedure and monitor function for 3 & 6 months before sacrifice. Principal
outcome measures will be: safety as measured by survival; efficacy as measured by capacity and
compliance of the neo-bladder.

The aim of this programme is to deliver a functional bladder reconstruction, through a cell/tissue engineering strategy, to children who require increased bladder capacity. Bladder exstrophy is a major congenital anomaly that affects the growth and function of the bladder. Despite improvement of the surgical techniques, the need for bladder augmentation in bladder exstrophy patients, in order to achieve an adequate bladder capacity is reported in up to 70% of children.
In the last 7 years at GOSH and Evelina, 106 children underwent a bladder augmentation and of those 26 were exstrophy patients (GOSH).
In general, the incidence of neonates born with bladder exstrophy or other congenital malformations is increasing and the results of the operations currently used for their correction are often disappointing, leaving these children with profound disabilities and poor quality of life. This has significant deleterious effects on both the family and the community. While the main focus the work of our group is on the bladder exstrophy, the use of a surrogate epithelium, such as the buccal mucosa here proposed, may have an impact also for other indications where bladder augmentation is required but autologous urothelium cannot be used, such as for neuropathic bladders and bladder cancer patients. The evidence suggests an increasing trend in the incidence of this malignancy in recent years. In 2000, worldwide, 336,000 patients were diagnosed with bladder cancer. Bladder augmentation is part of the armoury of the urologist / paediatric urologist in the treatment of urinary incontinence. Urinary incontinence is associated with tremendous costs and results in medical and psychological morbidity and adverse effects on quality of life. In general, urinary incontinence, secondary to congenital and acquired diseases, is experienced by some 3 million people in the UK and the cost of management is over £500 million per annum to the NHS. At the moment, although bladder augmentation can provide continence and enhance quality of life, it is commonly associated with serious complications, such as mucus production, formation of stones, recurrent urinary infection, metabolic imbalance and for some, in the long term, malignant change. Management of these complications can require additional medication, bladder washouts and occasionally hospitalisation treatment. The aim of this project is to provide a safe alternative to bowel segments for augment the bladder that will improve clinical outcomes and the quality of life for these patients and their families by reducing their risk of serious sequelae. This in turn will reduce the cost burden for the NHS of lifelong management of such complex patients and their complications. Once validated, the proposed surgical approach to composite cystoplasty will be easily and quickly translated into clinical application. We also envisage that this research may have, in the long term, a wider economic impact. This is based on the fact that our results could be of interest not only for the cure of congenital anomalies, but also for the treatment of acquired diseases in children, as well as in adults of all ages. Moreover tissue engineering is linked to advances in technology and is likely to generate commercial interests. If our approach would prove to be correct, possible patents could be generated for commercially exploitable results. It is not our primary interest to develop a patent, but we believe that this could help acquiring future grants and fostering of future research.