Ionic Homeostasis and Stress-Induced Aging of Human Mesenchymal Stem Cells.

This paper describes changes in ionic homeostasis associated with premature senescence in human endometrial mesenchymal stem cells (eMSCs). Changes in the intracellular potassium and sodium content and potassium fluxes through the plasma membrane have been examined/ with flame photometry, It was found that, during oxidative stress-induced cell-cycle arrest and the development of premature aging, eMSCs retained the high ionic heterogeneity that is common for functionally active animal cells. Premature cell aging is accompanied by increased intracellular sodium content and transmembrane potassium fluxes associated with the functioning of the Na/K pump, but does not affect the passive transport of potassium across the plasma membrane. One distinctive feature of stress-induced arrested eMSCs is reduced specific intracellular potassium content (500–600 μmol per 1 g of protein) compared to proliferating eMSCs (800–900 μmol per 1 g of protein). It is suggested that decreased intracellular potassium content associated with the development of premature aging shows the participation of potassium ions in the regulation of cell volume and may indicate a decreased hydration of aging eMSCs. [ABSTRACT FROM AUTHOR]