Caracterización y biocompatibilidad de las prótesis vasculares de poliuretano estabilizado con polidimetilsiloxano

Biomaterial research and development efforts have yielded new vascular prosthesis showing improved behaviour as small calibre grafts. Objective. The present study was designed to evaluate the biological behaviour of vascular prostheses made of polyurethane. Material and methods. Prostheses: polyurethane-polydimethylsiloxane (PU-PDMS). Characterization: fragments of PU-PDMS were examined by light and scanning electron microscopy. The electrical charge of the prosthetic material's inner surface was determined by spectral analysis. Biocompatibility: fragments (1 cm2) of PU-PDMS were grafted to the dorsal muscle of New Zealand rabbits (n= 18) and maintained for 3 or 8 months when they were subjected to morphological, immunohistochemical (anti-actin) and foreign body reaction (RAM11) analysis. Seeding: fragments (1 cm2) were seeded with endothelial cells from human umbilical vein. Follow-up times were 24, 48, 72 h and 7 days. Results. The biomaterial is of fibrous composition and has numerous pores. The inner biomaterial surface shows areas of negative charge. At three months, the prosthesis was observed to be embedded in a highly vascularised neoformed tissue that was rich in white blood and foreign body reaction cells. Eight months after grafting, the biomaterial was fully infiltrated by host tissue and enveloped by highly vascularised collagen. At 24 h of seeding, endothelialisation of the prosthetic surface was noted, with the exposure of large pores that became lined with cells at subsequent stages. Conclusions. The characteristics shown by the PUPDMS prosthesis: structure, no rejection and good integration with host tissue in the mid- and long-term are suitable for its use as a vascular substitute.