Nanofiber alignment regulates adhesion and integrin expression of human mesenchymal stem cells and tendon fibroblasts

Rotator cuff tears are among the most common shoulder injuries that require surgery. High failure rates of biological graft-based repairs underscore the need for functional alternatives. In this study, effects of nanofiber organization on adhesion of cuff fibroblasts (hRCF) and human mesenchymal stem cells (hMSC) are evaluated. It is hypothesized that fiber alignment will regulate cell morphology and integrin gene expression. hRCF and hMSC were seeded on aligned and unaligned nanofiber scaffolds of polylactide-co-glycolide. Cell morphology (n=3) and gene expression (n=5) for integrins ¿2, ¿V, ¿5, and ß1 were determined over 14 days. Cell morphology was found to differ between groups. Higher ¿2 and ß1 expressions in hRCF and hMSC on aligned scaffolds suggest aligned scaffolds a more biomimetic structure to native tendon, since integrin ¿2ß1 facilitates cell attachment to collagenous matrices. Expressions for ¿V and ¿5, which are associated with tendon healing, were significantly higher on unaligned scaffolds, and suggest a healing response by the cells. In conclusion, the cells may recognize differences in matrix organization, and fiber alignment regulates cell adhesion. Moreover, the aligned nanofiber matrix may promote a more biomimetic fibroblast response than the unaligned scaffold.