Background: The Mild Behavioral Impairment Checklist (MBI-C), a screening scale for neuropsychiatric symptom evaluation, facilitates Alzheimer's disease (AD) screening. However, its validity and reliability for use as an AD screening tool have not been determined. Objective: To develop an AD screening scale suitable for the Chinese population. Methods: The MBI-C was translated into Chinese and back-translated with the original author's consent. Forty-six AD patients, attending the Xuanwu hospital memory clinic, and 50 sex-and education-matched controls from the community underwent a full neuropsychological evaluation, including MBI-C assessment. Among them, 15 AD patients were evaluated repeatedly, and eight were evaluated simultaneously by two different clinicians, to assess MBI-C reliability. Results:The MBI-C demonstrated good internal consistency reliability, test-retest reliability, and inter-rater reliability. Its optimal cutoff point was 6/7 for identifying AD dementia, with a sensitivity of 86.96% and specificity of 86.00%, and its detection rate for moderate-severe AD dementia was higher than that of the Neuropsychiatric Inventory Questionnaire (NPI-Q). Pearson's correlation coefficients ranged from 0.702 to 0.831, indicating content validity. Seven factors were extracted during principal component analysis, with a cumulative contribution of 70.55%. Moreover, the Pearson's correlation coefficient was 0.758, indicating its criterion validity. The MBI-C could also distinguish AD dementia severity. MBI-C scores were significantly negatively correlated with MMSE and MoCA scores, and positively correlated with ADL scores. Conclusion:This study showed that the Chinese version of MBI-C has high reliability and validity, and could replace the NPI-Q for AD dementia screening in the Chinese population.

Exosome secretion is an important paracrine way of endothelial progenitor cells (EPCs) to modulate resident endothelial cells. The osteocalcin (OCN)-expressing EPCs have been found to be increased in cardiovascular disease patients and are considered to be involved in the process of coronary atherosclerosis. Since OCN has been proven to prevent endothelial dysfunction, this study aimed to evaluate the effect of exosomes derived from OCN-overexpressed EPCs on endothelial cells. Exosomes derived from EPCs (Exos) and OCN-overexpressed EPCs (OCN-Exos) were isolated and incubated with rat aorta endothelial cells (RAOECs) with or without the inhibition of OCN receptor G protein-coupled receptor family C group 6 member A (GPRC6A). The effects of exosomes on the proliferation activity of endothelial cells were evaluated by CCK-8 assay, and the migration of endothelial cells was detected by wound healing assay. A tube formation assay was used to test the influence of exosomes on the angiogenesis performance of endothelial cells. Here, we presented that OCN was packed into Exos and was able to be transferred to the RAOECs via exosome incorporation, which was increased in OCN-Exos groups. Compared with Exos, OCN-Exos had better efficiency in promoting RAOEC proliferation and migration and tube formation. The promoting effects were impeded after the inhibition of GPRC6A expression in RAOECs. These data suggest that exosomes from OCN-overexpressed EPCs have a beneficial regulating effect on endothelial cells, which involved enhanced OCN-GPRC6A signaling.

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