Aerosol transfer of bladder urothelial and smooth muscle cells onto demucosalized colonic segments: a pilot study

We developed a cell transfer technology for covering demucosalized colonic segments with bladder urothelium. This covering would be achieved through aerosol spraying of single cell suspension of bladder urothelial and smooth muscle cells with fibrin glue onto the demucosalized colonic segments.

In 6 piglets (20 kg.) a 4 cm.2 area of bladder was excised. Single cell suspension of bladder urothelial and smooth muscle cells was prepared. A segment of detubularized sigmoid colon was isolated on its vascular pedicle and demucosalized. The single cell suspensions were combined with an equal volume of fibrin glue and sprayed over the raw submucosal surface of the sigmoid segment. The sigmoid segment was retubularized and sutured to the posterior peritoneum. Animals were sacrificed 4 weeks later, and the segment was submitted to histological and immunohistochemical analysis.

Sigmoid segments appeared grossly intact with no reduction in surface area. Hematoxylin and eosin architecture revealed an intact urothelial layer. Deep to this layer was a randomly aligned but distinctly segregated layer of smooth muscle cells. The urological new smooth muscle layer stained positive for calponin and the urothelial layer was cytokeratin-7 and uroplakin III positive.

Separation, cell suspension and aerosol delivery of bladder urothelial and smooth muscle cells in fibrin glue can successfully transfer these urological cell populations to a new host tissue commonly used in urological reconstruction. In vivo co-culture of bladder smooth muscle and urothelial cells results in coverage of a large area of demucosalized gut providing new potential for transfer and reconstitution of urologically functionally appropriate tissue to the bladder itself.