Platelet system changes associated with a training period of 18-20 months: a transverse and a longitudinal approach

The acute effect of the antioxidant drug "U-74389G" on mean platelet volume levels during hypoxia reoxygenation injury in rats

Background

This experimental study examined the effect of the antioxidant drug "U-74389G", on a rat model and particularly in a hypoxia - reoxygenation protocol. The effects of that molecule were studied hematologically using blood mean platelets volume (MPV) levels.

Methods

40 rats of mean weight 231.875 g were used in the study. MPV levels were measured at 60 min of reoxygenation (groups A and C) and at 120 min of reoxygenation (groups B and D). The drug U-74389G was administered only in groups C and D.

Results

U-74389G administration kept significantly increased the predicted MPV levels by 12.77 ± 3.07% (p = 0.0001). Reoxygenation time non-significantly decreased the predicted MPV levels by 2.55 ± 3.71% (p = 0.4103). However, U-74389G administration and reoxygenation time together kept significantly increased the predicted MPV levels by 7.09 ± 1.91% (p = 0.0005).

Conclusions

U-74389G administration whether it interacted or not with reoxygenation time kept significantly increased the predicted MPV levels. This finding has great clinical interest in blood clotting and coagulation pathophysiology.

Relationship between platelet phospholipid FA and mean platelet volume in healthy men

Increased mean platelet volume (MPV) has been suggested as an independent risk factor for acute myocardial infarction and the increased reactivity of large platelets. The aim of this study was to investigate the correlation between platelet phospholipid (PL) PUFA composition and MPV in 139 free-living healthy men ages 20-55 yr (vegans, n = 18; ovolacto vegetarians, n = 43; moderate meat-eaters, n = 60; and high meateaters, n = 18). Each subject completed a semiquantitative Food Frequency Questionnaire and gave a blood sample. Platelet PL FA composition and MPV were determined by standard methods. MPV was significantly greater in the vegans than in the ovolacto vegetarian, moderate, or high meat-eater groups (P < 0.01). Both vegan and ovolacto vegetarian groups had significantly higher platelet PL 18:2n-6 and 22:4n-6, and lower 20:5n-3 and 22:6n-3 compared with the moderate and high meat-eater groups. The vegans demonstrated a significant reduction in 20:4n-6 and 22:5n-3 compared with the ovolacto vegetarian, high meat-eater, and moderate meat-eater groups. Bivariate analysis results showed that MPV was significantly positively correlated with platelet PL 18:2n-6 (P = 0.048) and negatively correlated with 20:3n-6 (P = 0.02), 20:5n-3 (P = 0.005), and 22:5n-3 (P< 0.0001), respectively. In a multiple linear regression analysis, after controlling for potential confounding factors such as dietary group, age, exercise, body mass index, and dietary polyunsaturated and saturated fat, cholesterol, carbohydrate, and fiber intake, the MPV was still strongly negatively correlated with platelet PL 20:3n-6 (P = 0.003) and 22:5n-3 (P = 0.001). The present data suggest that 22:5n-3 and 20:3n-6 may play a role in the structural function of the platelet membrane.

Mean platelet volume improves upon the megathrombocyte index but cannot replace the blood film examination in the evaluation of thrombocytopenia

The measurement of the number of platelets larger than 3 microns (megathrombocyte index) is the first element in the evaluation of thrombocytopenia. This is currently performed by counting the number of large platelets on the peripheral blood film. The MPV (mean platelet volume) is an automated measurement of the platelet volume. This study examines the mean values, correlations, sensitivity, specificity and the receiver operating characteristic curve (comparison of two tests) to determine which of these tests better separates the production state. For increased vs. decreased production, the MPV was 10.0 + 1.9 fL and 8.0 + 1.5 fL (P < .0001) respectively and the megathrombocyte index (MEGA) was 19.0 + 17.6% and 11.5 + 14.9% (P < .007) respectively. The correlation with the state of production was better for MPV (R = .47) than for MEGA (R = .20). For the MPV a sensitivity of 80% occurred with the MPV > or = 8.4 fL with a specificity of 71%. For a MEGA > or = 6%, the sensitivity was 80% but the specificity was 43%. For any MPV the sensitivity and specificity were better than for any MEGA. The Receiver Operating Characteristic Curve demonstrated that the MPV is a better test than the MEGA for separating the production into increased and decreased states. The MPV is a better test than the MEGA and will add to, but not replace, examination of the peripheral blood film in the diagnosis of thrombocytopenia.