A spike in mechanotransductive adenosine triphosphate release from red blood cells in microfluidic constrictions only occurs with rare donors

OBJECTIVE: Wan et al (Proc Natl Acad Sci USA, 105, 2008, 16432) demonstrated that RBCs rapidly and transiently release a spike of 300% more ATP shortly downstream from a short microfluidic constriction where the cells experience a sudden increase in shear stress. More recent work by Cinar et al (Proc Natl Acad Sci USA, 112, 2015, 11783), however, yielded no evidence for a similar spike in ATP release downstream of the constriction. Our aim was to determine whether a transient spike in mechanotransduction is the typical response of RBCs to the sudden onset of increased shear. METHODS: We investigate ATP release downstream of a microfluidic constriction for 15 participants using a luciferase‐based photoluminescent assay. RESULTS: While we observe mechanotransductive ATP release from blood drawn from all donors, we find evidence of a spike in ATP concentration after the microfluidic constriction for only 2 of 15 participants. No clear trends in ATP release are found with respect to the magnitude of the applied shear stress, or to the gender, age, or physical activity (Baecke) index of the donor. CONCLUSIONS: In aggregate, all data acquired to date suggest that a spike in mechanotransductive ATP due to a suddenly applied increase in shear stress occurs in blood drawn from only 14% of the population.