Human bone marrow mesenchymal stem cells (hBM-MSCs) represent a potentially valuable cell type for clinical therapeutic applications. The present study was designed to evaluate the effect of long-term culturing (up to 10(th) passages) of hBM-MSCs from eight individual amyotrophic lateral sclerosis (ALS) patients, focusing on functional ion channels. All hBM-MSCs contain several MSCs markers with no significant differences, whereas the distribution of functional ion channels was shown to be different between cells. Four types of K(+) currents, including noise-like Ca(+2)-activated K(+) current (IK(Ca)), a transient outward K(+) current (I(to)), a delayed rectifier K(+) current (IK(DR)), and an inward-rectifier K(+) current (K(ir)) were heterogeneously present in these cells, and a TTX-sensitive Na(+) current (I(Na,TTX)) was also recorded. In the RT-PCR analysis, Kv1.1, heag1, Kv4.2, Kir2.1, MaxiK, and hNE-Na were detected. In particular, I(Na,TTX) showed a significant passage-dependent increase. This is the first report showing that functional ion channel profiling depend on the cellular passage of hBM-MSCs.
Keywords: Bone marrow; Functional ion channels; Passage-dependency; Stem cells; Tetrodotoxin-sensitive Na+ current.