Platelet and Red Blood Cell Counts, as well as the Concentrations of Uric Acid, but Not Homocysteinaemia or Oxidative Stress, Contribute Mostly to Platelet Reactivity in Older Adults

Abstract

Purpose The goal of this study was to estimate the hierarchical contribution of the most commonly recognized cardiovascular risk factors associated with atherogenesis to activation and reactivity of blood platelets in a group of men and women at ages 60-65. Methods Socioeconomic and anthropometric data were taken from questionnaires. Blood morphology and biochemistry were measured with standard diagnostic methods. Plasma serum homocysteine was measured by immunochemical method. Plasma concentrations of VCAM, ICAM, total antioxidant status, and total oxidant status were estimated with commercial ELISA kits. Markers of oxidative stress of plasma and platelet proteins (concentrations of protein free thiol and amino groups) and lipids (concentrations of lipid peroxides) and generation of superoxide anion by platelets were measured with colorimetric methods. Platelet reactivity was estimated by impedance aggregometry with arachidonate, collagen, and ADP as agonists. Expression of selectin-P and GPIIb/IIIa on blood platelets was tested by flow cytometry. Results Platelet aggregation associated significantly negatively with HGB and age and significantly positively with PLT, MPV, PCT, PDW, and P-LCR. When platelet reactivity (“cumulative platelet reactivity_aggregation”) was analyzed in a cumulated manner, the negative association with serum concentration of uric acid (Rs = −0.169, p = 0.003) was confirmed. Multivariate analysis revealed that amongst blood morphological parameters, platelet count, plateletcrit, and number of large platelets and uric acid are the most predictive variables for platelet reactivity. Conclusions The most significant contributors to platelet reactivity in older subjects are platelet morphology, plasma uricaemia, and erythrocyte morphology.

Hydroxyvitamin D Serum Levels are Negatively Associated with Platelet Number in a Cohort of Subjects Affected by Overweight and Obesity

“…Platelet number also showed an inverse association with uric acid, and this result is in line with previous studies showing a potential role of uric acid in affecting platelet activation and reactivity [32]. Therefore, while hyperuricemia is commonly associated to a higher cardiovascular risk [33], low levels of uric acid may also be a risk factor through increased platelet numbers.…”

Retrospective Analysis of the Correlation between Uric Acid and Thyroid Hormone in People with Normal Thyroid Function

“…Uric acid levels were found to be associated with benign positional vertigo, but were not an independent risk factor [6]. A study has also suggested that plasma uric acid levels are associated with platelet reactivity in the elderly [7]. The uric acid level increase is believed to be an intermediary factor in adipose tissue that regulates endocrine disorders that promote inflammation and may be an important factor leading to dyslipidemia and atherosclerosis [8].…”

Cardiovascular Risk Factors and Haematological Indexes of Inflammation in Paralympic Athletes with Different Motor Impairments

“…It has been reported that RBC, HGB, and HCT were negatively significantly associated with platelet aggregation, suggesting an effect of RBC-derived NO on P aggregability [54]. NO, produced in RBC membrane and cytoplasm by endothelial-type nitric oxide synthase (eNOS), inhibited platelet aggregation [54].…”

“…It has been reported that RBC, HGB, and HCT were negatively significantly associated with platelet aggregation, suggesting an effect of RBC-derived NO on P aggregability [54]. NO, produced in RBC membrane and cytoplasm by endothelial-type nitric oxide synthase (eNOS), inhibited platelet aggregation [54]. On the other hand, it has been reported that low concentrations of plasma amino acids, including L-arginine, the precursor for NO synthesis, in malnourished patients enhanced the occurrence of thrombotic events [55, 56].…”