Tissue engineered extracellular matrices (ECMs) in urology: Evolution and future directions

Autologous gastrointestinal tissue has remained the gold-standard reconstructive
biomaterial in urology for >100 years. Mucus-secreting epithelium is associated with
lifelong metabolic and neuromechanical complications when implanted into the
urinary tract. Therefore, the availability of biocompatible tissue-engineered
biomaterials such as extracellular matrix (ECM) scaffolds may provide an attractive
alternative for urologists. ECMs are decellularised, biodegradable membranes that
have shown promise for repairing defective urinary tract segments in vitro and in vivo
by inducing a host-derived tissue remodelling response after implantation. In urology,
porcine small intestinal submucosa (SIS) and porcine urinary bladder matrix (UBM)
are commonly selected as ECMs for tissue regeneration. Both ECMs support
ingrowth of native tissue and differentiation of multi-layered urothelial and smooth
muscle cells layers while providing mechanical support in vivo. In their native
acellular state, ECM scaffolds can repair small urinary tract defects. Larger urinary
tract segments can be repaired when ECMs are manipulated by seeding them with
various cell types prior to in vivo implantation. In the present review, we evaluate and
summarise the clinical potential of tissue engineered ECMs in reconstructive urology
with emphasis on their long-term outcomes in urological clinical trials.