PhD ThesisMSCs (N=9) were isolated from the bone marrow of patients who had received hip
replacement therapy. MSC-serum free conditioned media (MSC-CM) were collected
at different time points during MSC passage and analysed for protein content using
enzyme linked immunosorbent assay (ELISA). The effect of MSC-CM was tested on
migration and proliferation of human skin cells (HaCat cell line, primary fibroblast and
primary keratinocytes) (N=4) using a 2D scratch assay and tetrazolium salt proliferation
assay respectively. For primary keratinocyte experiments, MSC-CM were collected in
keratinocyte growth media containing low calcium levels (0.04 mM/L) (LC-CM). The
effect of LC-CM was tested on migration and proliferation of primary keratinocytes
during different testing conditions; normoxia (N=4), hypoxia (N=4), blocking of stromal
derived factor-1α (SDF-1α) (N=4) and inhibition of proliferation (N=4). MSCs were
tested for their ability to differentiate into epidermal like cells (ELCs) using both 2D and
3D cultures. A human 3D skin model was developed for wound healing and micro RNA
profiling studies. All MSCs met the criteria stipulated by the International Society for
Cellular Therapy (ISCT). MSC-CM contained growth factors e.g. keratinocyte growth
factor (KGF), hepatocyte growth factor (HGF), platelet derived growth factor-AB
(PDGF-AB), transforming growth factor-β1 (TGF-β), macrophage stimulating protein1 (MSP-1) and SDF-1α and RT qPCR analysis demonstrated receptors of these growth
factors e.g. FGFR2, c-MET, PDGFRA, TGFβ-R1, RON and CXCR4 respectively on
both scratched and non-scratched primary keratinocytes. The main findings from this
study showed that MSCs could differentiate into ELCs and MSC-CM were shown to
have a positive effect on migration and proliferation of skin cells in 2D and 3D culture.
MSC secretions collected at early time points were more effective on cell migration
than those collected at later time points during MSC expansion. 2D and 3D studies
also showed that cell migration was the first and the major mechanism evoked by MSCCM followed by proliferation and differentiation. Additionally, the 3D skin model
developed in this study could be used as a skin replica for wound healing studies at
the cellular and molecular level including the use of microRNA profiling. These
microRNAs were regulated at different time points during the wound repair suggesting
their participation in the different phases of the healing process. In conclusion, MSCs
play a multifunctional role in the cellular and molecular mechanisms of the healing
process and enhance the healing process via two mechanisms; cell mediated repair
by differentiation into ELCs and secretory mediated repair by cytokines.the Higher Committees for Education Development in Iraq
(HCED) and Al-Nahrain Universit