Xenogeneic-free platform for the isolation and scalable expansion of human bladder smooth muscle cells

Smooth muscle cells (SMC) play a crucial role in bladder tissue engineering strategies. Scalable, Good Manufacturing Practice (GMP)-compliant platforms are essential for producing clinically relevant cell numbers.

A gamma-irradiated human platelet lysate (HPL) supplement was used to develop a xeno(geneic)-free process for the isolation and scalable expansion of human bladder-derived SMC.

Cells were isolated using an explant-based technique and expanded ex vivo, expressing typical SMC markers (α-SMA, desmin, caldesmon and SM22-α). Cell culture was successfully scaled-up using spinner flasks combined with plastic microcarriers, starting with a 2.8 × 10³ cells/cm² inoculum (i.e. 1 × 10⁶ cells). Cell-microcarrier adhesion rates exceeded 80% within 24 hours with fold expansion ranging from 3.5 to 16.8 after 7 days, dependent on donor variability. Harvested cells retained their SMC phenotype.

This xeno-free, GMP compliant process enables scalable manufacturing of human bladder-derived SMC while preserving cell identity, potentially advancing clinical applications in bladder engineering.