Northwestern University researchers investigated engineering strategies to regenerate urinary bladder tissue, including growing cells on small intestinal submucosa (SIS) prior to implantation

The team found that increasing the numbers of cells grown on SIS scaffolds prior to implanting them in animals could increase both blood vessel and muscle formation.

Diseases and traumatic events, such as radiation treatment for bladder cancer, spina bifida, or battlefield injuries, can affect urinary bladder tissue function. While these cases often can be treated by bladder augmentation (enlarging the bladder with portions of intestine), the treatment has side effects that can negatively impact a patient’s health and quality of life.

Engineering strategies for bladder augmentation attempt to create bladder tissue that mimics native tissue in structure and function. Current strategies include reconstructing bladder tissue with pliable scaffolds combined with stem cells. In a recent report,¹ Dr. Arun Sharma’s team at Northwestern University in Chicago grew combinations of bone marrow mesenchymal cells and CD34+ hematopoietic (blood-forming) stem/progenitor cells on either an elastic synthetic mesh, POC [poly(1,8 octamethylene citrate)], or small intestinal submucosa (SIS), a natural biological scaffold.

Dr. Sharma’s team compared different combinations of cell numbers to determine the optimum number of cells for bladder tissue regeneration. Bladder augmentation was performed in male and female nude rats by removing about 50% of the bladder and replacing it with a cell-seeded scaffold. Increasing the number of cells seeded on the scaffolds increased the area of blood vessels in the regenerated bladder tissue after 10 weeks in the females, regardless of scaffold type. Increasing the number of cells seeded on the POC scaffold also increased the percent of muscle regeneration that occurred, but again only in the female rats. Changing the number of cells did not change any of the outcomes in the male rats. There was no significant difference in urinary function with increasing cell numbers in either group.

This study assessed the regenerative capacity of bladder tissue when using POC or SIS scaffolds with various cell-seeding numbers. All groups regenerated tissue, and there was a trend for higher cell numbers to increase blood vessels and muscle growth.

1. Bury MI, Fuller NJ, Sturm RM, Rabizadeh RR, Nolan BG, Barac M, Edassery SS, Chan YY, Sharma AK. The effects of bone marrow stem and progenitor cell seeding on urinary bladder tissue regeneration. Scientific Reports. 2021:11:2322.