Background/Purpose: Adult stem cells, namely those of mesenchymal origin (MSCs), have received attention as an ideal source of regenerative cells because of their multi-potential ability to replicate. Adipose tissue (AT) is an alternative attractive source of MSCs, due to its abundance and surgical accessibility. Recent studies have shown that autologous fat grafting may be effective in the treatment of specific skin lesions in systemic sclerosis (SSc), but no specific study exists aimed at investigating whether AT-MSCs in patients with SSc maintain normal phenotypic and functional characteristics. Aim of the study was to investigate whether AT-MSCs from patients with SSc (SSc-AT-MSCs) are phenotypically and functionally identical to those from healthy controls (HCs)

Methods: AT samples were obtained from 8 patients with the diffuse cutaneous variant of SSc (dcSSc) and from 5 HCs. Key parameters of AT-MSC phenotype and function were assessed in both MSC populations, including the capacity (a) to express specific MSC surface antigens (CD105, CD73, CD29, CD90, CD44) by FACS analysis, (b) to proliferate (growth kinetics assay), (c) to differentiate along the adipogenic and osteogenic lineages, (d) to suppress in vitro lymphocyte proliferation induced by the mixed lymphocyte reaction (MLR), and (e) to support endothelial cell (EC) tube formation.

Results: AT-MSCs from SSc patients and HC showed similar cell surface phenotype and multilineage differentiation capabilities. Phenotypically, SSc- and HC-AT-MSCs highly expressed CD105, CD73, CD90, HLA-ABC and were mostly negative for HLA-DR expression. When cultured in standard induction medium, both SSc- and HC-AT-MSCs similarly differentiated toward the osteogenic and adipogenic lineages. In MLR assays, no significant differences in AT-MSC-mediated inhibition of proliferation were observed between SSc- and HC-AT-MSCs. Using AT-MSC/EC co-cultures, we observed that both SSc- and HC-AT-MSCs improve tube formation by both HC- and SSc-ECs. This effect was enhanced under hypoxic conditions in all of the co-cultures.

Conclusion: Our study shows that AT-MSCs from patients with SSc exhibit the same phenotypic pattern, proliferative and differentiation potentials, as well as the same immune-suppressive properties than those from HC. The SSc-AT-MSC activity we observed as pro-angiogenic effectors, namely under hypoxic conditions, may suggest that autologous AT-MSCs grafting may represent a future possible therapeutic option in patients with this disorder.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/phenotypical-and-functional-characteristics-of-in-vitro-expanded-adipose-derived-mesenchymal-stem-cells-from-patients-with-systemic-sclerosis/