The role and mechanism of erythroid precursor cells in Alzheimer's disease

Objective To investigate the role and mechanism of erythroid precursor cells (EPC) and its subtypes in Alzheimer's disease (AD). Methods The patients with AD (AD group) firstly diagnosed and treated in Qinghai Provincial People's Hospital from October 2018 to October 2019 were included, and olanzapine combined with donepezil were used for treatment; while 30 healthy volunteers were selected as the control group. The proportion of EPC, CD45+EPC and CD45-EPC in peripheral blood in control group and AD group before and after treatment was detected and sorted by flow cytometry. Primary cortical neurons were used to construct AD cells model, flow cytometry was used to detect the apoptosis of neurons in control group, AD model group, CD45+EPC group, CD45-EPC group and Artemin block group. Results There was no significant difference in the proportion of EPC in peripheral blood between AD group and control group, or between AD group before and after treatment (P＞0.05, for all). However, the proportion of CD45+EPC subtype (t=7.277, P=0.000) and ROS content (t=10.817, P=0.000) in AD group before treatment were higher than those in control group. The proportion of CD45-EPC subtype (t=7.277, P=0.000) and Artemin content (t=6.547, P=0.000) were lower than those in control group, but there were no significant differences in proportion of CD45+EPC and CD45-EPC subtypes, ROS and Artemin contents before and after treatment in AD group (P＞0.05, for all). Neuronal apoptosis experiment showed the proportion of neuronal apoptosis in different treatment groups was significantly different (F=25.662, P=0.000). The proportion of neuronal apoptosis in AD model group (t=9.330, P=0.000), CD45+EPC group (t=14.362, P=0.000), CD45-EPC group (t=2.423, P=0.036) and Artemin block group (t=9.970, P=0.000) were higher than those in control group. AD model group (t=4.548, P=0.001), CD45+EPC group (t=8.759, P=0.000), Artemin block group (t=5.387, P=0.000) were higher than those in CD45-EPC group. CD45+EPC group was also higher than that in AD model group (t=5.091, P=0.000) and Artemin block group (t=3.175, P=0.004). Conclusions The proportion of CD45+EPC subtype in peripheral blood of AD patients was significantly increased and the proportion of CD45-EPC subtype was decreased. CD45-EPC subtype can reduce the neuronal apoptosis induced by AD by secreting Artemin.