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

Abstract

Human platelet polyphosphate (polyP) is a multifunctional molecule; however, its functions are not yet fully understood. A recent study demonstrated that similar to skeletal muscle, polyP is involved in energy metabolism in platelets, which suggests that well-trained athletes may exhibit elevated platelet polyP levels for energy storage. To test this hypothesis, we quantified platelet polyP along with NADH, a component involved in ATP production in non-trained and well-trained male Japanese participants of the same generation. Washed platelets were prepared from the venous blood of young, healthy, non-athletes, and professional soccer players (pro-athletes). NADH and polyP levels were spectrophotometrically determined using tetrazolium reduction and fluorometrically determined using 4′,6-diamidino-2-phenylindole at the excitation/emission wavelengths of 425/525 nm. Body weight and impedances were measured simultaneously. Statistical analyses were performed using the Mann-Whitney U test and Spearman correlation coefficient. Although basal metabolic rate levels were significantly higher, platelet polyP levels were significantly lower in pro-athletes than in that in non-athletes. No significant differences were detected in other body compositions or platelet indices between the two groups. The pro-athlete group showed a moderate, nearly significant correlation (R = 0.439; p = 0.0512) between platelet polyP and NADH levels. Taken together with the weak correlation data between polyP and body mass index, it is suggested that platelet polyP levels may be influenced by platelet and body energy metabolic activity. Further biochemical studies are needed to elucidate this mechanism.

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

“…Reciprocal conversion between ATP and polyP is thought to occur depending on the metabolic activity. This possibility was observed in a previous study of professional athletes [ 10 ]. We also found that such reciprocal conversion rarely occurs in the platelets of non-athletes at rest.…”

“…Platelet polyP cellular metabolism, subcellular localization, and individual variability have all been poorly investigated because of the lack of clarity and controversy around the analytical methodologies. In a recent study [ 10 ] using modified DAPI-based methods, we suggested that energy metabolism, that is, the reciprocal conversion between ATP and polyP, could vary between professional athletes and non-athletes. We studied the impact of metabolic inhibitors and energy supplements on polyP levels to further explore the mechanism underlying this difference.…”

“…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 ]. This finding has motivated further studies to better understand the mechanism underlying the potential conversion of these energy-rich molecules.…”

The levels of TGFβ1, VEGF, PDGF-BB, and PF4 in platelet-rich plasma of professional soccer players: a cross-sectional pilot study

“…However, we believe that several other factors modulate the therapeutic potential of PRP through potentiation and suppression and are present in individual PRP preparations [30]. The candidate factor that we have recently paid attention to is polyphosphate (polyP) [31][32][33][34][35][36][37]. PolyP is an ancient, but still mysterious, biopolymer that is produced in the mitochondria in the extension of the ATP production line [33,34,38] and stored in the dense granules of platelets.…”

“…The candidate factor that we have recently paid attention to is polyphosphate (polyP) [31][32][33][34][35][36][37]. PolyP is an ancient, but still mysterious, biopolymer that is produced in the mitochondria in the extension of the ATP production line [33,34,38] and stored in the dense granules of platelets. Upon platelet activation, polyP is released alongside growth factors, and this impacts the immunological functions of platelets in addition to hemostatic function [32].…”