Cardiac Specific Gene Expression Changes in Long Term Culture of Murine Mesenchymal Stem Cells

Murine MSCs are a readily available source of adult stem cells enabling extensive in vitro study of this cell population. MSCs have been described as multipotent, and have been proven capable of differentiation into several connective tissue types. Furthermore some studies have suggested an ability to differentiate into non-connective tissue cell types such as the cardiomyocyte. The aim of this study was to differentiate murine MSCs toward cardiac lineage with the commonly used method of culture with 5’ Azacytidine. Critically, baseline analysis of gene expression of passage four MSCs demonstrated expression of key cardiac markers including cardiac troponin T and I, and the ryanodine receptor. Furthermore, expression analysis of these genes changed with time in culture and passage number. However, there was no significant alteration when cells were subjected to a differentiation protocol. This study therefore highlights the importance of analyzing baseline cells extensively, and indicates the limitations in extrapolating data for comparison between species. Furthermore this data brings into question the efficacy of cardiac differentiation using MSCs

Characterisation and cardiac directed differentiation of canine adult cardiac stem cells

This study describes the isolation and characterisation of adult canine cardiac stem cells, and explores their ability to differentiate into cardiac myocytes. Direct comparisons are also made with available human data. Atrial cardiac explants were taken from dogs post-mortem and cultured to isolate adult stem cells. Cells were able to survive successive passages in serum-free media, were able to form cardiospheres, and under controlled culture conditions were capable of clonal expansion, demonstrating their ability for self-renewal. Characterisation of these cells demonstrated the following marker profile: c-kit, GATA 4 and flk-1 positive; cardiac troponin T and NKx2.5 low. Cardiac lineage directed differentiation was performed based on the published literature. Gene expression studies demonstrated that cardiac directed differentiation was partially achieved, with up-regulation of cardiac troponin T and NKx2.5, and down-regulation of c-kit and endothelial lineage markers. However the cells did not express the ryanodine receptor or β(1)-adrenergic receptors and did not contract spontaneously

Characterisation and differentiation potential of bone marrow derived canine mesenchymal stem cells

Mesenchymal stem cells (MSCs) have potential for use in regenerative therapeutics, since they are capable of multi-lineage differentiation. In this study, primary canine MSCs (cMSCs) were isolated from bone marrow aspirates and characterised using marker expression and morphology. cMSCs expressed CD44 and STRO-1, but not CD34 or CD45. Morphologically, cMSCs were similar to previously described MSCs and were capable of chondrocyte differentiation towards articular type cartilage, characterised by increased collagen type II vs. collagen type I expression and expression of Sox-9. cMSCs demonstrated no significant alterations in marker profiles and failed to differentiate into cardiomyocytes in response to a cardiac differentiation protocol or when co-cultured with canine cardiac stem cells. The study indicated that cMSCs can be derived readily from bone marrow and are capable of differentiation into articular cartilage, but appear to have limited ability to differentiate into cardiomyocytes using current protocols