Current status of tissue engineering applied to bladder reconstruction in humans

Design of a Mechatronics Model of Urinary Bladder and Realization and Evaluation of Its Prototype

Annually, there are many bladder cancer patients undergoing radical cystectomy (RC) with urinary diversion worldwide. Until 2019, intestinal cystoplasty is still the gold standard for bladder replacement, but this therapy is always associated with severe complications. An ideal bladder substitute without using intestinal tissue remains a challenge today. In this work, an artificial mechatronics bladder (AMB) as a brand new bladder replacement approach is developed. We studied the main physiological function characteristics of a natural urinary bladder from teaching books and relevant papers. According to these characteristics, we completed an overall design of AMB and made a prototype in lab. The prototype successfully realized the functions of a natural bladder in vitro. It can expand to store urine in real time when urine is flowing into it. It can send a urination alarm when it is fully filled and can void urine automatically after receiving remote control signals. According to relevant papers and our test experience, if the prototype could be smaller and lighter and manufactured with good biocompatibility materials such as PTFE, we think it is possible for AMB to be implanted in an animal's body, and we deduce AMB could realize the functions of a natural urinary bladder in vivo. After thorough validation from animal testing, we hope AMB can be a good clinical option for bladder removal patients in the future.

Use of an acellular collagen-elastin matrix to support bladder regeneration in a porcine model of peritoneocystoplasty

Introduction

Bladder reconstruction without using the intestine remains a challenge to this day despite the development of new biomaterials and cell cultures. Human bladder engineering is merely anecdotic, and mostly in vitro and animal studies have been conducted.

Material and methods

In our study using a porcine model, we performed a bladder augmentation using an autologous parietal peritoneum graft (peritoneocystoplasty) and determined whether the attachment of an acellular collagen-elastin matrix (Group 1) or lack of (Group 2) had better histologic and functional results. Thus far, peritoneocystoplasty has rarely been performed or combined with a biomaterial.

Results

After 6 weeks, we observed different degrees of retraction of the new bladder wall in both groups, although the retraction was lower and the histological analysis showed more signs of regeneration (neoangiogenesis and less fibrosis) in Group 1 than when compared with Group 2. No transitional cells were found in the new bladder wall in any of the groups, and no differences were observed in the functional test results.

Conclusions

Performing a peritoneocystoplasty is an easy and safe procedure. The data supports the benefit of an acellular collagen–elastin matrix to reinforce bladder regeneration. However, in our study we observed too much retraction of the new wall and the histologic results were not acceptable to consider it an appropriate cystoplasty technique.