Intermittent Fasting During Ramadan Increases the Absolute Number of Circulating Progenitor Stem Cells in Healthy Subjects

Fasting regimens have shown profound impact on pro-longevity and tissue regeneration in diverse species. Physiological events can induce a regenerative response in adult stem cells. However, little is known about signaling and activation of adult stem cells which are modulated by fasting. This study analyzed the presence of hematopoietic stem/progenitor cells (HSPCs) and their circulation in the peripheral blood (PB) of healthy male adults practicing Ramadan fasting. Ten healthy male volunteers were enrolled in this prospective observational study. PB samples were collected twice daily on days 0, 10, 20, and 30 of Ramadan fasting (RF). Populations of stem cells and serum soluble factors were analyzed by flow cytometry. As a response to RF, we report an increase in the average absolute count of circulating of HSPCs, defined as LIN^-CD45^- and LIN^-CD45⁺ cell subsets expressing the stem markers, CD34 and CD133. Changes in the number of HSPCs subsets reflected changes in the peripheral concentration of chemoattractant soluble factors during fasting. A chemotaxis assay showed a migratory property of HSPCs towards plasma, collected at D30 of fasting that contained a higher concentration of SCF and G-CSF. The relationship between RF and an increase in the number of circulating HSPCs in part, describes a regenerative response to the physiological changes during fasting and may open opportunities to define the role of dietary intervention in the stem cell therapy.