Multilineage Differentiation Potential of Equine Adipose-Derived Stromal/Stem Cells from Different Sources

SIMPLE SUMMARY: Adult multipotent mesenchymal stem/stromal cells (MSCs) have the ability to self-renew and differentiate into various cell types. MSCs, especially those derived from adipose tissue (ASCs), are easily available and abundant. In order to expand the current knowledge of clinically relevant properties of ASCs obtained from equine abdominal, retrobulbar and subcutaneous adipose tissue using explantation and collagenase digestion, the study’s aim was to investigate the proliferation and multilineage differentiation potential of equine ASCs in vitro. ASCs showed a high proliferation and adipogenic, osteogenic and chondrogenic differentiation potential, whereby a significant effect of the tissue localization and isolation procedure was detected in the case of adipogenic and osteogenic differentiation. However, equine ASCs were refractory to activin A, bone morphogenetic protein-4 and Dickkopf-1-induced upregulation of cardiomyogenic marker expression, characteristic for in vitro cardiomyogenesis. Follow-up studies are required to further investigate the effect of isolation methods and tissue sources on clinically relevant multilineage differentiation potential in equine MSCs. Moreover, the use of stem cells with higher pluripotency should be considered for in vitro cardiomyogenesis in further studies. ABSTRACT: The investigation of multipotent stem/stromal cells (MSCs) in vitro represents an important basis for translational studies in large animal models. The study’s aim was to examine and compare clinically relevant in vitro properties of equine MSCs, which were isolated from abdominal (abd), retrobulbar (rb) and subcutaneous (sc) adipose tissue by collagenase digestion (ASCs-(SVF)) and an explant technique (ASCs-(EXP)). Firstly, we examined proliferation and trilineage differentiation and, secondly, the cardiomyogenic differentiation potential using activin A, bone morphogenetic protein-4 and Dickkopf-1. Fibroblast-like, plastic-adherent ASCs-(SVF) and ASCs-(EXP) were obtained from all sources. The proliferation and chondrogenic differentiation potential did not differ significantly between the isolation methods and localizations. However, abd-ASCs-(EXP) showed the highest adipogenic differentiation potential compared to rb- and sc-ASCs-(EXP) on day 7 and abd-ASCs-(SVF) a higher adipogenic potential compared to abd-ASCs-(EXP) on day 14. Osteogenic differentiation potential was comparable at day 14, but by day 21, abd-ASCs-(EXP) demonstrated a higher osteogenic potential compared to abd-ASCs-(SVF) and rb-ASCs-(EXP). Cardiomyogenic differentiation could not be achieved. This study provides insight into the proliferation and multilineage differentiation potential of equine ASCs and is expected to provide a basis for future preclinical and clinical studies in horses.