Impact of Laminin Coating on the Autologous In Vivo Recellularization of Decellularized Aortic Grafts

Objectives: The decellularization of non-autologous, biological implants allows a reduction of the immune and inflammatory responses against donor tissue. To accelerate the autologous in vivo recellularization of aortic prostheses for an enhanced biocompatibility, we tested laminin surface coating in a standardized rat implantation model.

Methods: Decellularized rat aortic grafts (n = 28) were surface-coated with laminin (1 mg/mL, 24h) and implanted into the systemic circulation of Wistar rats for 2 and 8 weeks (n = 9 per time point). Uncoated implants served as controls (n = 5 for each time point). Cellular repopulation of the implants was examined by scanning electron microscopy (n = 10), histology and immunofluorescence (n = 18).

Results: Laminin coating was persistent for at least 8 weeks. After 2 weeks, no relevant re-colonization of the intimal surface was observed. At 8 weeks, neoendothelialization was significantly accelerated in the laminin group (p = 0.0048). Interestingly, the intima-to-media thickness ratio was significantly decreased in the laminin group (p = 0.0149). Medial recellularization did not differ between both groups (p = 0.6370). Originating from the adventitial surface, α-smooth muscle actin-positive invasion into the media was observed in both groups in a similar manner. In the laminin group and in the control group, intima and media calcification occurred to the same extent. In both groups, inflammatory cell markers (CD3 and CD68) proved negative.

Conclusion: Laminin coating of decellularized aortic grafts showed in vivo persistence for at least 8 weeks. This treatment resulted in accelerated autologous recellularization and reduced intima hyperplasia. In summary, laminin coating may be a promising approach to improve the biocompatibility of tissue-engineered vascular implants.

No conflict of interest has been declared by the author(s).