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

Platelets produce inorganic polyphosphate (polyP) upon activation to stimulate blood coagulation. Some researchers have linked polyP metabolism to ATP production, although the metabolic linkage is yet to be elucidated. We found evidence for this possibility in our previous study on professional athletes (versus non-athletes), and proposed that the regulatory mechanism might be different for these two groups. To explore this aspect further, we investigated the effects of modulated ATP production on polyP levels. Blood samples were obtained from Japanese healthy, non-athletes in the presence of acid-citrate-dextrose. The platelets in the plasma were treated with oligomycin, rotenone, and GlutaMAX to modulate ATP production. PolyP level was quantified fluorometrically and visualized using 4′,6-diamidino-2-phenylindole. Correlations between polyP and ATP or NADH were then calculated. Contrary to the hypothesis, inhibitors of ATP production increased polyP levels, whereas amino acid supplementation produced the opposite effect. In general, however, polyP levels were positively correlated with ATP levels and negatively correlated with NADH levels. Since platelets are metabolically active, they exhibit high levels of ATP turnover rate. Therefore, these findings suggest that ATP may be involved in polyP production in the resting platelets of non-athletes

Endovascular Therapy Is Effective for Leriche Syndrome with Deep Vein Thrombosis

A 65-year-old man presented to our hospital due to intermittent claudication and swelling in his left leg. He had Leriche syndrome and deep vein thrombosis. We performed endovascular therapy (EVT) for Leriche syndrome, and a temporary filter was inserted in the inferior vena cava. He received anticoagulation therapy for deep vein thrombosis. The stenotic lesion in the terminal aorta was stented with an excellent postprocedural angiographic result and dramatic clinical improvement after EVT. This case suggests that EVT can be a treatment for Leriche syndrome

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

Impact of Platelet Reactivity to Adenosine Diphosphate Before Implantation of Drug-Eluting Stents on Subsequent Adverse Cardiac Events in Patients With Stable Angina

Background: Diverse pharmacological effects of anti-platelet thienopyridines due to individual differences in metabolism have been reported. However, an association between on-treatment platelet reactivity and adverse ischemic events after drug-eluting stent (DES) implantation in Japanese patients has not been fully elucidated. Methods and Results: A total of 450 consecutive patients on dual anti-platelet therapy (aspirin and ticlopidine) with stable angina who underwent DES implantation were enrolled. Adenosine diphosphate (ADP)-induced platelet aggregation was measured before DES implantation using the screen filtration pressure method. The ADP concentration necessary for 50% aggregation was designated as the platelet aggregation threshold index (PATI). A composite primary endpoint of cardiac death, myocardial infarction, target lesion revascularization (TLR), and stent thrombosis occurring within 1 year after stenting, was evaluated. A PATI value <4.8 mu mol/L was defined as high on-treatment reactivity to ADP. The composite primary endpoint occurred in 55 patients (12.2%) in the 1-year-period after DES implantation, and the prevalence was 19.0% and 5.1% in groups with high and low on-treatment reactivity to ADP, respectively, showing a significantly higher prevalence in the high reactivity group (P<0.001). The main event was TLR (18.1% vs. 5.1%, P<0.001). Conclusions: These data suggested that high on-treatment platelet reactivity to ADP and subsequent occurrence of adverse ischemic events (particularly TLR) were correlated in patients with stable angina who underwent DES implantation. (Circ J 2012; 76: 641-649