Human multipotent adult progenitor cell-conditioned medium improves wound healing through modulating inflammation and angiogenesis in mice

Abstract

Background Stem cell therapies have been widely investigated for their healing effects. However, the translation of these therapies has been hampered by the requirement to deliver live allogeneic or autologous cells directly to the wound in a clinical setting. Multipotent adult progenitor cells (MAPC® cells) are a subpopulation of bone marrow-derived adherent stem cells that secrete a wide range of factors known to accelerate the wound healing process. The aim of this study was to determine the impact of MAPC cells secretome on healing outcomes without the presence of MAPC cells. Methods The effect of MAPC-conditioned medium (MAPC-CM) on the capacity of keratinocytes, fibroblasts and endothelial cells to migrate and proliferate was determined in vitro using scratch wound closure and WST1 assay, respectively. The effect of MAPC-CM on collagen deposition and angiogenesis was also assessed using in vitro methods. Additionally, two excisional wounds were created on the dorsal surface of mice ( n = 8/group) and 100 μL of 20× MAPC-CM were intradermally injected to the wound margins. Wound tissues were collected at 3, 7 and 14 days post-wounding and stained with H&E for microscopic analysis. Immunohistochemistry was performed to investigate inflammation, angiogenesis and collagen deposition in the wounds. Results Skin fibroblasts, keratinocytes and endothelial cells treated with MAPC-CM all showed improved rates of scratch closure and increased cellular proliferation. Moreover, fibroblasts treated with MAPC-CM deposited more collagens I and III and endothelial cells treated with MAPC-CM showed increased capillary tube formation. Murine excisional wounds intradermally injected with MAPC-CM showed a significant reduction in the wound area and an increase in the rate of reepithelialisation. The results also showed that inflammatory cell infiltration was decreased while an increase in angiogenesis, as well as collagens I and III expressions, was observed. Conclusion These findings suggest that factors produced by MAPC cells can have an important effect on cutaneous wound healing by affecting skin cell proliferation and migration, balancing inflammation and improving the formation of extracellular matrix and angiogenesis. Development of stem cell-free therapy for the treatment of wounds may be a more clinically translatable approach for improving healing outcomes.

Mesenchymal Stem Cell Secretome as an Emerging Cell-Free Alternative for Improving Wound Repair

“…The MSC secretome (MSC-S) then influences neighbouring cells and regulates multiple biological processes [ 42 ]. Currently, paracrine or trophic properties are considered as the primary means of the therapeutic effect of MSCs [ 26 , 40 , 43 ]. Although MSCs derived from different organs share phenotypic and regenerative characteristics, their secretome is different and depends on their origin, which consequently can lead to different therapeutic potentials [ 44 ].…”

“…The number of MSCs that are required to produce sufficient quantities of secretome for an equivalent effect on acute wounds is about 10–25 times higher than directly administered live cells [ 43 ]. These elevated numbers of cells impact the costs of derivation and validation because the biological properties and activity of these cells may change with repeated passages.…”

Multipotent adult progenitor cells grown under xenobiotic-free conditions support vascularization during wound healing

“…Micro-array studies on hMAPC cells grown in regular growth media have shown a superior pro-angiogenic expression profile compared to MSCs [13], yet the factors responsible for the superior pro-angiogenic effect remain to be determined. In a recent study by Ahangar et al, it was demonstrated that hMAPC-secreted factors had positive effects on skin cell proliferation, migration, collagen deposition, and the hMAPC secretome improved wound healing without the presence of MAPC cells [22]. This further supports the e-h Cross-sections zooming in on the wound center stained for mCD31 in green for CTRL (e; black circles in h; n = 15), XF2 (f; blue triangles in h; n = 16), and XF3 (g; red triangles in h; n = 16) groups and the corresponding quantification in h. Data represent the mean fraction of mCD31 + vessels expressed as number per area (in mm 2 ) ± S.E.M.…”

“…Micro-array studies on hMAPC cells grown in regular growth media have shown a superior pro-angiogenic expression profile compared to MSCs [ 13 ], yet the factors responsible for the superior pro-angiogenic effect remain to be determined. In a recent study by Ahangar et al, it was demonstrated that hMAPC-secreted factors had positive effects on skin cell proliferation, migration, collagen deposition, and the hMAPC secretome improved wound healing without the presence of MAPC cells [ 22 ]. This further supports the notion that the benefit of hMAPC cells is mostly related to their trophic effect on the healing process.…”

Human gingival fibroblast secretome accelerates wound healing through anti-inflammatory and pro-angiogenic mechanisms

“…Although a number of studies have suggested a vital role for direct contact by stem cells for mediating their effects 13 , other studies suggest that only secreted factors are required for the immunomodulatory and regenerative effects of stem cells 14 . More recently, stem cell secretomes, generally in the form of conditioned media (CM), have been investigated as an alternative cell-free therapy in regenerative medicine 15 , 16 .…”