Mean platelet volume in diabetes mellitus

We measured mean platelet volume (MPV) in patients with diabetesmellitus, compared with MPV in non-diabetic control subjects.Mean MPV was significantly increased in the diabetic subjects(8.9 ± 0.07 fL, mean ± SEM) compared with nondiabeticsubjects (8.0 ± 0.05) (p < 0.001). Since plateletsize is a determinant of platelet function, with larger plateletsbeing more reactive per unit volume, we believe platelets mayplay a part in the micro- and macro-vascular complications ofdiabetes mellitus.     

Platelet coagulant activities in diabetes mellitus. Evidence for relationship between platelet coagulant hyperactivity and platelet volume

Platelets have been shown to be capable of initiating and promoting some of the reactions in intrinsic coagulation and have been implicated in the pathogenesis of vascular lesions in diabetes mellitus. We have examined the contribution of platelets to the coagulation reactions in 39 patients having diabetes mellitus with and without retinopathy [background retinopathy (BR) or proliferative retinopathy (PR)], 18 patients with nonvascular eye diseases (patient controls), and 38 normal subjects. As compared to control patients, significant elevations were noted in four of the five assays for platelet coagulant activities in diabetic patients with PR and in three of five assays in patients with BR. Thus platelet coagulant hyperactivity is present in diabetics with retinopathy. Significant elevations were noted in two of the assays in patients without retinopathy (NR), suggesting that platelet coagulant hyperactivity may not necessarily be secondary to the vasculopathy. The predominant abnormalities noted were in assays reflecting the contribution of platelets to the early stages of intrinsic coagulation rather than to later stages of prothrombin activation. In addition, the mean platelet volume was found to be significantly greater in patients with PR and BR but not NR than in normal controls. A positive linear correlation (r = 0.81) was noted between the mean of the coagulant activities and platelet volume in diabetic subjects, suggesting a hitherto undescribed relationship between platelet coagulant activities and platelet volume.     

Mean platelet volume and the ratio of mean platelet volume to platelet count in the diagnosis of acute appendicitis

Background

Mean platelet volume (MPV) is an inflammatory marker. Recent studies have shown that there is a negative correlation between platelet count (PC) and MPV and that the ratio of these two values may be more meaningful. The aim of our study was to investigate the diagnostic value of MPV and the MPV/PC ratio in acute appendicitis.

血小板平均体积在老年重症社区获得性肺炎中的应用价值

目的 探讨血小板平均体积在老年重症社区获得性肺炎(SCAP)中的应用价值,为老年SCAP的严重程度提供更多的依据.方法 老年SCAP组患者31例,老年非SCAP组75例,健康对照组55例,收集临床及实验室指标进行比较分析.结果 老年SCAP组血小板平均体积(MPV)较对照组明显升高(10.46±1.01) fl vs (9.77±0.91) fl(P＜0.01),老年SCAP组也较老年非SCAP组升高(10.46±1.01) fl vs (9.88±0.82) fl(P＜0.01),老年非SCAP组和正常对照组差异无统计学意义.MPV工作者特征曲线(ROC)诊断老年SCAP的最佳界值为10.25 fl,MPV大于10.25 fl时敏感度54.8%,特异度73.3%,阳性诊断价值59.0%,阴性诊断价值12.0%,曲线下面积(AUC)0.666(P<0.01).老年SCAP组MPV与白细胞计数呈正相关,与血小板计数、C反应蛋白无明显相关.结论 MPV作为一个简单指标一定程度反映了社区获得性肺炎的严重程度和炎症的程度,其在诊断老年SCAP中敏感性较低.     

Evidence for abnormal platelet glycoprotein expression in diabetes mellitus

In 41 diabetics (27 type I, 14 type II) and in 23 healthy controls the number of glycoprotein (GP) GPIB and GPIIB/IIIA molecules were determined on resting, peripheral platelets by means of flowcytometry after immunostaining with monoclonal antibodies which bind independently from the state of activation. The average number of both glycoproteins per platelet was significantly elevated (GPIB: 54,100 x 1.27 +/- 1 vs. 39,100 x 1.3 +/- 1 GPIIB/IIIA: 77,500 x 1.3 +/- 1 vs. 62,700 x 1.3 +/- 1, in diabetic patients. Platelet volume was significantly correlated with the number of GPIB molecules on normal and diabetic platelets (r (normal) = 0.52 +/- 0.07; r (diabetic) = 0.46 +/- 0.1). Additionally, von Willebrand factor-related antigen (vWF: AG) was increased to 129% x 1.3 +/- 1 in diabetics vs. 111% x 1.4 in controls. The increase of vWF: AG was significantly correlated with HbA1 (r = 0.38*) and seemed to depend on chronic hyperglycaemia. Since platelet glycoprotein receptor status is regulated by the bone-marrow megakaryocyto- thrombopoiesis, our observations support the hypothesis that platelet hyperactivity in the diabetic state may be due to primarily altered production of platelets with an increased number of functional glycoproteins. This may be paralleled by increased plasma levels of cytoadhesive proteins like vWF: AG, which interact with the studied glycoproteins and thereby potentiate the risk of disturbed microhaemorrheology.     

Primary platelet activation in recent-onset type 1 diabetes mellitus

Platelet function (as production of thromboxane B2 by platelets stimulated with collagen, and plasma beta-thromboglobulin) and thrombin activity (as plasma fibrinopeptide A) were investigated in eight young (mean age 27 +/- 3 SE years) male patients in which type 1 diabetes mellitus had been diagnosed 2 to 6 months previously. They were all in excellent stable metabolic control (mean HbA1c 5.6 +/- 0.4 SE %) and free from any complications. The haemostatic variables were assessed at rest and after cycloergometric exercise to exhaustion. When compared to age- and sex-matched healthy controls, patients showed higher beta-thromboglobulin, fibrinopeptide A and thromboxane B2 at rest. After exercise, plasma beta-TG increased only in the controls. Platelet and thrombin activation are present in the very early stages of type 1 diabetes mellitus, in the absence of any complications.     

Mean platelet volume is increased in patients with severe obstructive sleep apnea

Abstract

Increased platelet activation and aggregation which are closely related to cardiovascular complications have been reported in patients with obstructive sleep apnea (OSA). The aim of this study was to assess the mean platelet volume (MPV), an indicator of platelet activation in patients with OSA. The 95 subjects referred for evaluation of OSA underwent overnight polysomnography. Blood samples were taken for MPV determination. According to the apnea-hypopnea index (AHI), subjects were divided into three groups; group 1: control subjects without OSA (AHI < 5, n = 24), group 2: patients with mild to moderate OSA (AHI: 5–30, n = 42), and group 3: severe OSA (AHI > 30, n = 29). Body mass index (BMI) of patients with severe OSA was significantly higher than control subjects (31.5 ± 4.0 vs. 28.2 ± 5.0; p = 0.02). The MPV was significantly higher in patients with severe OSA than in the control group (8.9 ± 1.0 vs. 8.2 ± 0.7 fl; p = 0.01). Correlation analysis within 71 patients with OSA indicated that MPV was correlated with AHI (p < 0.001, r = 0.44) and DI (p = 0.001, r = 0.37). In multivariate regression analysis, when MPV was taken as independent with other study variables which are potential confounders such as age, gender and BMI, MPV was independently correlated with both AHI (β = 0.44, p < 0.001) and DI (β = 0.38, p < 0.001). We have shown that MPV was significantly higher in patients with severe OSA when compared with control subjects and MPV was correlated with AHI and DI.     

Mean platelet volume/platelet count ratio predicts severe pneumonia of COVID‐19

BackgroundAlthough platelet mean volume/platelet count ratio (MPR) is considered to be a crucial marker of inflammatory and infectious diseases, the relationship between MPR and novel coronavirus infectious disease 2019 (COVID‐19) remains unclear.MethodsIn this retrospective study, 85 patients with confirmed COVID‐19 were enrolled and divided into low and high MPR group. Data from repeated measures were compared by the generalized estimating equations. Cox regression analyses were performed to assess the impact of MPR on the incidence of severe pneumonia (SP), with inverse probability of treatment weighting (IPTW) used to reduce confounding bias. The primary outcome is the incidence of SP of COVID‐19.ResultsDuring follow‐up, 17 (20.0%) patients were developed to SP. Compared with mild patients, patients with SP developed showed a higher MPR level at baseline, day 1, day 2, and day 3 after admission (P = .005, P = .015, P = .009, and P = .032, respectively). Kaplan‐Meier method showed a higher incidence of SP in the high MPR group than the low MPR group (log‐rank test = 10.66, P = .001). After adjustment, high MPR was associated with an elevated incidence of SP (HR, 5.841, 95% CI, 1.566‐21.791, P = .009). The IPTW method also suggested that MPR was a significant factor related to the incidence of SP (HR, 8.337, 95% CI, 4.045‐17.182, P < .001).ConclusionHigh MPR level is an independent risk factor for severe pneumonia in patients with COVID‐19.     

Decreased numbers of platelet alpha-adrenergic binding sites in diabetes mellitus

Eleven men with diabetes mellitus were compared with 45 male controls for platelet alpha-adrenergic binding sites by using [3H]dihydroergocryptine (DHE) as the radioligand antagonist. There was no difference between the two for binding affinity, but the number of sites was 430 +/- 30 (means +/- SEM) for diabetic subjects and 574 +/- 29 for controls (P = .005). Decreased sites were related to increased glycosylated hemoglobin levels (P = .002). There was no relationship between the decreased sites and catecholamine levels, duration of disease, body weight, or fasting blood sugar. Hence, binding sites were inversely related to control, but further studies are needed to define the pathophysiologic significance of this.     

Effect of vitamin E on platelet aggregation in diabetes mellitus

Vitamin E is known to be an inhibitor of platelet prostaglandin production and aggregation. The rate of platelet aggregation induced by adenosine diphosphate was significantly increased in diabetics with proliferative retinopathy, and the enhanced production of thromboxane B2, a stable metabolite of thromboxane A2, was demonstrated in those patients. On the other hand, vitamin E was significantly reduced in platelets obtained from diabetics as compared to age matched control subjects. In addition, it was shown that vitamin E content in platelets examined in diabetic and control subjects inversely correlated with both the rate of platelet aggregation and thromboxane B2 production during aggregation. It is suggested that the reduced vitamin E levels in diabetic platelets can contribute to the mechanisms of the enhanced platelet thromboxane A2 production and aggregation which lead to the development of vascular complications.     

Glycation of platelet protein in diabetes mellitus: lack of correlation with platelet function

The relationship of nonenzymatic glycation of platelet proteins to altered platelet function was studied in 33 diabetic patients. Platelets isolated from diabetic patients were glycated to a greater extent than those isolated from nondiabetic controls. No relationship was found between the level of glycation of platelets in diabetics to parameters commonly used to monitor glycemic control (glycated hemoglobin, glycated albumin, fasting blood glucose). Platelets isolated from diabetics did not show an increased level of aggregation and Thromboxane B2 production as compared to nondiabetic controls. No significant relationship was found between the level of glycation and percent aggregation of platelets. The lack of a relationship between glycation and aggregation suggests that the former may not be responsible for the functional changes in platelets seen in diabetics.     

2型糖尿病微血管病变患者血小板平均体积与尿清蛋白排泄率的关系

目的探讨血小板平均体积(MPV)及尿清蛋白排泄率(UAER)在糖尿病微血管病变患者中测定的意义及关系。方法对67例糖尿病微血管病变患者分别采用全自动血细胞分析仪和免疫散射比浊法测定血小板平均体积及UAER,并与20例糖尿病无血管并发症组和30例正常对照组比较。结果糖尿病微血管病变组血小板平均体积(11．43±2．00)及UAER(2．07±0．62)均显著高于正常对照组8．69±1．85(P＜0．01)、0．97±0．18(P＜0．01)和糖尿病无血管并发症组9．02±1．91(P＜0．01)、1．05±0．23(P＜0．01);而糖尿病无血管并发症组与正常对照组间血小板平均体积及UAER差异无统计学意义(P＞0．05);糖尿病微血管病变患者大量清蛋白尿组MPV(12．29±2．11)显著高于正常清蛋白尿组10．02±0．90(P＜0．01)和微量清蛋白尿组11．08±1．82(P＜0．05),微量清蛋白尿组显著高于正常清蛋白尿组(P＜0．05)。结论MPV及UAER的检测,对糖尿病微血管病变的发生、发展及早期诊断和治疗具有重要意义,是反映糖尿病徽血管病变范围及病变程度的指标。     

Mean platelet volume as a fibrosis marker in patients with chronic hepatitis B

Introduction: Many noninvasive tests have been studied for the diagnosis and determining the liver fibrosis score (LFS). In this study, we aimed to research the correlation of mean platelet volume (MPV) and stage of liver fibrosis in patients with chronic hepatitis B (CHB). Patients and Methods: Fifty‐nine patients with CHB were enrolled retrospectively into the study. Age–sex matched 25 healthy subjects were used as control group. The following data were obtained from computerized patient registry database: HBV‐DNA level, hepatitis B e‐antigen seropositivity, liver enzymes and function tests, white blood cell count, platelet count, hemoglobin, histological activity index, LFS, and MPV. Patients were divided into two groups: patients without significant fibrosis (F0, F1, or F2) (Group 1) and patients with advanced fibrosis (F3, F4) (Group 2). Results: A statistically significant increase in MPV was seen in patients with CHB compared with healthy controls (8.49±0.84 fl vs.7.65±0.42 fl, P<0.001). Receiver operating characteristic curve analysis suggested that the optimum MPV level cut‐off points for CHB was 8.0 fl, with sensitivity, specificity, PPV, and NPV of 68, 76, 86, and 50%, respectively. MPV levels were significantly higher in Group 2 (8.91±0.94 fl, P: 0.009) compared with Group 1 (8.32±0.74 fl). ROC curve analysis suggested that the optimum MPV level cut‐off points for Group 2 was 8.45 fl, with sensitivity, specificity, positive and negative predictive value of 77, 59, 45, and 85%, respectively. Multivariable logistic regression model, which consisted of HAI, ALT, HBV‐DNA, platelet count, and MPV, was performed. We showed that MPV was independently associated with advanced fibrosis (P: 0.031). Conclusion: We suggest that MPV might help in the assessment of fibrosis in CHB. It should not be considered a stand‐alone test for this use owing to nonspecificity with other diseases. J. Clin. Lab. Anal. 25:162–165, 2011. © 2011 Wiley‐Liss, Inc.