Smooth muscle spheroids: Superior building blocks for bladder tissue engineering.

Background: Congenital bladder disorders in children necessitate innovative approaches for bladder tissue regeneration, aiming to minimize complications associated with conventional therapies. This study focused on generating a cell-seeded scaffold using superior smooth muscle cells (SMCs) by exploring the potential of smooth muscle cell spheroids (3D SMCs) compared to conventionally cultured SMCs (2D SMCs) for bladder tissue engineering. Additionally, adipose-derived stem cells (ADSCs) were investigated for their impact on SMC proliferation and maturation, and pre-differentiated smooth muscle-like ADSCs (pADSCs) for their potential as alternative cell source.

Methods: 3D SMCs were seeded into a compressed collagen scaffold as monoculture and as co-culture with ADSCs or pADSCs and incubated for 2 weeks. Their contractile potential as well as proliferation and cell distribution within the scaffold were compared to conventionally cultured 2D SMCs by immunofluorescent staining and qRT-PCR.

Results: 3D SMCs in collagen scaffolds exhibited significantly superior cell distribution, proliferation, and contractile marker expression compared to 2D SMCs. While ADSCs showed limited impact, co-culture with pADSCs enhanced contractile marker expression, though not surpassing 3D SMC monoculture.

Conclusion: For the first time, a collagen scaffold seeded with 3D SMCs was generated and evaluated. This study recommends 3D SMCs as optimal building blocks for bladder tissue engineering, highlighting the potential of pADSCs as an alternative cell source. These findings offer crucial insights for refining cell sources as well as culture techniques in pediatric bladder regeneration and provide a superior cell-seeded scaffold for further bladder tissue engineering experiments.