Bladder reconstruction using autologous smooth muscle cell sheets grafted on a pre-vascularized capsule

Area of Science:

• Regenerative Medicine
• Biomaterials Science
• Vascular Biology

Background:

• Functional vascularized 3D tissue construction is a key goal in tissue engineering.
• Developing methods for vascularizing engineered tissues is critical for their survival and function.
• Smooth muscle tissue flaps are needed for reconstructive surgery, particularly for bladder augmentation.

Purpose of the Study:

• To evaluate the efficacy of using a tissue expander capsule as an induced vascular bed.
• To prefabricate functional vascularized smooth muscle tissue flaps for bladder reconstruction.
• To assess the performance of these flaps in a rabbit bladder defect model.

Main Methods:

• Skin tissue expanders were used to create vascularized capsule pouches.
• Smooth muscle cells and endothelial progenitor cells were co-cultured to form cell sheets.
• Cell sheets were repeatedly grafted onto capsular tissue to create vascularized flaps.
• Flaps were used to repair bladder defects and evaluated over 3 months.

Main Results:

• The "sheet plus capsule" group maintained bladder capacity and compliance for 3 months.
• Contractile responses to carbachol and KCl were significantly different across groups.
• Higher vessel density was observed in groups utilizing the capsule compared to "sheet only".
• Reduced inflammation and fibrosis were noted in the "sheet plus capsule" group.

Conclusions:

• Tissue expander capsules can serve as effective induced vascular beds for tissue flap prefabrication.
• Prefabricated vascularized smooth muscle tissue flaps offer potential for reliable bladder reconstruction.
• This approach presents new opportunities for achieving vascularization in 3D tissue engineering.