Effects of SARS‑CoV‑2 mRNA vaccines on platelet polyphosphate levels and inflammation: A pilot study

Abstract

Platelets function as immune cells in conjunction with white blood cells, targeting invading pathogens and inducing immune reactions. Intercellular communications among these immune cells are partly mediated by platelet polyphosphate (polyP), which was originally recognized as a thrombotic and hemostatic biomolecule. To determine the involvement of polyP in SARS-CoV-2-mRNA vaccine-induced immune responses, specifically in inflammatory responses, the effects of mRNA vaccines on platelet polyP levels were examined. Before and after vaccination with the COVID-19 vaccine (BNT162b2), blood samples were obtained from healthy, non-smoking individuals who did not have any systemic diseases. Test group demographics skewed somewhat towards either older males (first vaccination, n=6; second vaccination, n=8) or younger females (first vaccination, n=14; second vaccination, n=23). polyP levels in washed platelets from the blood samples were determined using the fluorometric method with DAPI. The side-effects of vaccination were recorded as scores. In the female group, platelet polyP levels decreased after the first vaccination, and the side-effect score increased after the second vaccination. Moderate correlation coefficients were observed between the reduction in polyP levels and the side-effect scores and pre-vaccination polyP levels. Despite the small sample size, this pilot study suggests that platelet polyP may suppress the side effects induced by the mRNA vaccines after the first vaccination, but not the second vaccination in younger female subjects, who generally have higher immune responsiveness than their male counterparts.

Platelet polyphosphate and energy metabolism in professional male athletes (soccer players): A cross‐sectional pilot study

“…An automated hematology analyzer was used to determine blood cell count and hemoglobin (HGB) levels. Samples within the optimized range were probed with 4 μl/sample (4 μg/ml) DAPI for 30 min at room temperature (18–22°C) and directly subjected to fluorescence measurements using a fluorometer (FC‐1; Tokai Optical Co., Ltd.) with excitation and emission wavelengths of 425 and 525 nm, respectively (Uematsu et al, 2022 ; Watanabe et al, 2021 ).…”

“…The number of non‐fixed, living platelets suspended in PBS was adjusted to a density ranging between 2.5 and 5.0 × 10 7 /100 μl, mixed with 10 μl WST‐8 solution (Dojindo Molecular Technologies, Inc.), and incubated for 1 h at room temerature (18‐23°C) under a dark environment. After centrifugation, the supernatants were analyzed using a spectrophotometer at 450 nm (SmartSpec Plus; Bio‐Rad Laboratories, Inc.), as described previously (Uematsu et al, 2022 ; Watanabe et al, 2021 ).…”

“…Based on the concept of mutual conversion between ATP/ADP and polyP (Borden et al, 2021 ; Müller et al, 2017 ; Pavlov et al, 2010 ), we postulated that elevated polyP levels are produced and stored in the platelets of elite athletes exhibiting more active energy generation systems than non‐athlete adults. Considering this quantification, we recently simplified and optimized a fluorescence intensity quantification protocol for polyP using 4′,6‐diamidino‐2‐phenylindole (DAPI) to handle numerous samples quickly without compromising reproducibility (Uematsu et al, 2022 ; Watanabe et al, 2021 ).…”

Modulation of ATP Production Influences Inorganic Polyphosphate Levels in Non-Athletes’ Platelets at the Resting State

“…Blood cell counts were performed using an automated hematology analyzer (pocHi V-diff, Sysmex Corporation, Kobe, Japan) before centrifugation and measuring platelet polyP levels to prepare the platelet suspension and adjust platelet counts, respectively [ 8 , 9 ]. If the histograms of platelet distribution did not display a smooth curve, the samples were discarded and not subjected to further polyP quantification.…”

“…In previous studies [ 7 , 8 ], the DAPI-dependent assay technique was improved, and its usefulness and reliability were validated. In a subsequent study, we found [ 9 ] that platelet polyP might suppress the SARS-CoV-2-mRNA vaccine-induced adverse effects following the first vaccination in young female participants, but not following the second vaccination. More recently, we found that platelets in professional athletes who exhibit higher metabolic activity than non-athletes may display a distinct regulatory system for maintaining the ATP–polyP balance, because polyP levels are correlated with cytoplasmic NADH levels [ 10 ].…”