Biocompatibility of heparin-coated PLLA-chitosan patch potentially usable for large blood vessel reconstruction: A Wistar rat histological study.

INTRODUCTION

Stroke remains a leading cause of disability and death globally, with carotid stenosis as a major contributor. Carotid endarterectomy with patch angioplasty reduces restenosis risk, but current patch materials often lack biocompatibility and biodegradability. This study introduces a novel vascular patch composed of poly-L-lactic acid (PLLA) and chitosan, coated with heparin, designed to promote tissue integration and safe degradation.

METHOD: A true experimental in vivo study was conducted using 54 Wistar rats, divided into three groups: (1) PLLA scaffold (Group K1/K2), (2) PLLA-chitosan scaffold (Group P1/P3), and (3) PLLA-chitosan with heparin coating scaffold (Group P2/P4). Histological analyses at 14 and 56 days post-implantation evaluated inflammatory response, fibrous capsule formation, and angiogenesis. Statistical analysis included ANOVA, T-test, and Mann-Whitney U test (significance p < 0.05).

RESULTS

At 14 days, inflammatory cell infiltration differed significantly among groups (p = 0.019), with the PLLA-chitosan patch showing the lowest inflammatory cell count. By 56 days, inflammation had subsided in all groups (p = 0.989). Initial fibrous capsule thickness at 14 days was higher in the heparin-coated group and differed significantly among groups (p = 0.019), but by 56 days all groups showed stable fibrous encapsulation with no significant differences (p = 0.916). All implants supported neovascularization, with evidence of new blood vessel formation (angiogenesis) around the patch materials. No excessive fibrous tissue formation or cytotoxic effects were observed in any group.

CONCLUSION

The heparin-coated PLLA-chitosan patch displayed good biocompatibility, modulating inflammation, and supporting neovascularization. These findings suggest its potential as a vascular graft for large vessel reconstruction, though further long-term studies are needed.