The senescence/quiescence status of adult stem/progenitor cells contributes to ageing process”, and “an individual is as old as old are its stem/progenitor cells”. Currently, these expressions are common among researchers involved in ageing studies and represent the object of their investigations. Investigations on contribution of stem/progenitor cells in ageing process are the flourishing field of research. As we age, our stem/progenitor cell populations gradually cease their activity, spending more time in periods of quiescence, and becoming more damaged by the wear and tear of continued metabolic activity. Their principal role is to provide a supply of new cells to keep tissues in working order, and diminished supply results in growing frailty and dysfunction. This is one of the causes of disease and death due to ageing. A detailed understanding of ageing biology of these cells is becoming of growing interest. Here, a summary of these aspects will be reported, emphasizing ageing of endothelial progenitor cells, as a typical example.
