Mechanical Mechanism of Circadian Fluctuations Regulated Haematopoietic Stems Cell Release

Haematopoietic stem cells (HSCs) circulate in the bloodstream under flow conditions, but the mechanical mechanisms of governing their physiological trafficking in mammals are still not yet clearly understood. The mobilization of HSCs and their progenitors into the circulation represents the basis for modern bone marrow transplantation procedures [1]. Recently, Mendez-Ferrer et al. performed experimental investigations on mice [2]. They demonstrated that the circulating HSCs and their progenitors exhibit robust circadian oscillations, and the circadian fluctuations could also be significantly altered when the HSCs were subjected to different time of lighting. These results indicated that the photic cues could affect the trafficking of HSCs in healthy animals. This implies that the light is the stimulus of HSCs release. When the HSCs are exposed to light, the HSCs release would markedly increase; when the HSCs are in darkness, the HSCs release keeps low efficiency. In this study, we numerically simulate this phenomenon to study the mechanical mechanism of circadian fluctuations regulated HSCs release under the influence of periodic lighting time.