Development of a bioengineered three-dimensional scaffold able to commit stem cells toward tenogenic phenotype

Abstract

The term tendinopathy is a generic descriptor of tendon disorders. Spontaneous adult tendon healing results in scar tissue formation and fibrosis, with impaired biological and mechanical properties. Adult tendons have a limited natural healing capacity, and often respond poorly to current treatments, including exercise, drug delivery and surgical procedures. To treat tendon diseases and support tendon regeneration, cell based therapy and tissue engineering approaches are considered options. None can however yet be considered conclusive in their restoration of a safe and successful long term solution for full microarchitecture and biomechanical tissue recovery. This thesis describes the work to develop an innovative bioengineered multiphasic three-dimensional scaffold, seeking to reproduce the complex microenvironment able to support tenogenic differentiation. Mesenchymal stem cells derived from human bone marrow (hBM-MSCs) are one of the main stem cells sources used in tissue engineering protocols while extra-embryonic cord-derived, including from Wharton’s Jelly (hWJ-MSCs), are emerging as useful alternatives. To explore the tenogenic plasticity of hBM-MSCs and hWJ-MSCs, we first conducted a pilot study treating both cell types with different doses of human Growth Differentiation Factor-5 (hGDF-5), a growth factor which induces tenogenic differentiation, improving the outcome of tendon repair. hGDF-5 induced the expression of genes (SCX-A, COL1A1, TNC, DCN, TNMD) and proteins (type I collagen, tenomodulin) linked to the neo-tendon phenotype in a time and concentration-dependent manner. The concentration of 100 ng/mL was the most effective for both stem cells types, coupled with specific alignment and shape modification. However, compared to hBM-MSCs, hWJ-MSCs showed higher proliferation rate and earlier up-regulation of tenogenic markers. ... [edited by Author]