Platelets are the primary peripheral reserve of amyloid precursor protein (APP), providing more than 90% of blood amyloid-beta (Aβ). Some oxidative stress markers and neurotransmitter markers were also differentially expressed in the peripheral platelets of AD. Therefore, the present study explored the differences in platelet-associated biomarkers between AD and healthy controls using meta-analysis and systematic review to reveal the value of platelet in the pathogenesis and development of AD.
We searched all the related studies that probed into the platelets in AD based on PubMed, Embase, and web of science databases from the establishment to November 04, 2021.
Eighty-eight studies were included in the meta-analysis, and the platelets data of 702 AD and 710 controls were analyzed. The results of standardized mean difference (SMD) showed that platelets in AD had lower levels of APP ratio (SMD: -1.89; p < 0.05), ADAM10 (SMD: -1.16; p < 0.05), Na + -K + -ATPase (SMD: -7.23; p < 0.05), but higher levels of HMW/LMW tau (SMD: 0.92; p < 0.05), adenosine A receptor (SMD: 4.27; p < 0.05), MAO-B (SMD: 1.73; p < 0.05), NO (SMD: 4.25; p < 0.05) and ONOO (SMD: 7.33; p < 0.05). In the systematic review, some other platelet markers seem to be meaningful in AD patients.
The results of the present meta-analysis and systematic review demonstrated that the alterations of APP metabolic enzymes, oxidative stress markers, and neurotransmitter factors in platelets were similar to their changes in the central nervous system of AD, suggesting that platelet could be a good source of peripheral biomarkers and may play an important role in the pathophysiological development of AD.

© 2023. The Author(s).