Immature platelet fraction in diabetes mellitus and metabolic syndrome

Commonalities of platelet dysfunction in heart failure with preserved ejection fraction and underlying comorbidities

Heart failure with preserved ejection fraction (HFpEF) is characterized by a lack of a specific targeted treatment and a complex, partially unexplored pathophysiology. Common comorbidities associated with HFpEF are hypertension, atrial fibrillation, obesity and diabetes. These comorbidities, combined with advanced age, play a crucial role in the initiation and development of the disease through the promotion of systemic inflammation and consequent changes in cardiac phenotype. In this context, we suggest platelets as important players due to their emerging role in vascular inflammation. This review provides an overview of the role of platelets in HFpEF and its associated comorbidities, including hypertension, atrial fibrillation, obesity and diabetes mellitus, as well as the impact of age and sex on platelet function. These major HFpEF-associated comorbidities present alterations in platelet behaviour and in features linked to platelet size, content and reactivity. The resulting dysfunctional platelets can contribute to further increase inflammation, oxidative stress and endothelial dysfunction, suggesting an active role of these cells in the initiation and progression of HFpEF. Recent evidence shows that reduced platelet count and elevated mean platelet volume are associated with worsening heart failure in HFpEF patients. However, the specific mechanisms by which platelets contribute to HFpEF development and progression are still largely unexplored, with only a few studies investigating platelet function in HFpEF. We discuss the limited yet significant body of research investigating platelet function in HFpEF, emphasizing the need for more comprehensive studies. Additionally, we explore the potential mechanisms through which platelets may influence HFpEF, such as their interactions with the vascular endothelium and the secretion of bioactive molecules like cytokines, chemokines and RNA molecules. These interactions and secretions may play a role in modulating vascular inflammation and contributing to the pathophysiological landscape of HFpEF. The review underscores the necessity for future research to elucidate the precise contributions of platelets to HFpEF, aiming to potentially identify novel therapeutic targets and improve patient outcomes. The evidence presented herein supports the hypothesis that platelets are not merely passive bystanders but active participants in the pathophysiology of HFpEF and its comorbidities.

Association of Red Blood Cell and Platelet Parameters with Metabolic Syndrome: A Systematic Review and Meta-Analysis of 170,000 Patients

This systematic review and meta-analysis aim to establish associations between metabolic syndrome (MetS) and erythrocyte and platelet markers, contributing to improved diagnostic tests for identifying individuals at risk. Observational studies and Randomized Controlled Trials (RCTs) were included. The standardized mean difference (SMD) and 95% confidence intervals (CI) of erythrocyte and platelet markers between individuals with and without MetS were used as effect size (inverse variance model). Methodological quality assessment was conducted using the Newcastle-Ottawa scale (NOS) for observational studies and the Cochrane Risk of Bias tool 2.0 for RCTs. The analysis included 51 articles. Compared to controls, individuals with MetS exhibited significantly higher concentrations of mean red blood cell count [Standardized Mean Difference (95% CI): 0.15 (0.13-0.18); p<0.00001], hemoglobin [0.24 (0.18-0.31); p<0.00001], blood platelet count [5.49 (2.78-8.20); p<0.0001], and red blood cell distribution width [(0.55 (0.05-1.04); p=0.03]. Regarding mean platelet volume [0.16 (- 0.03 to 0.35); p=0.10] and platelet-to-lymphocyte ratio (PLR) [7.48 (-2.85-17.81); p=0.16], a non-significant difference was observed in patients with MetS. There was no statistically significant difference in hematocrit counts between the two groups [0.47 (-0.40 to -1.34); p=0.29]. Biomarkers such as mean red blood cell count, hemoglobin, blood platelet count, and RDW are associated with higher levels in patients in MetS, whereas mean platelet volume and PLR tend to be lower. These markers can potentially provide new avenues for early diagnosis of MetS.

Temporal in vivo platelet labeling in mice reveals age-dependent receptor expression and conservation of specific mRNAs

The proportion of young platelets, also known as newly formed or reticulated, within the overall platelet population has been clinically correlated with adverse cardiovascular outcomes. However, our understanding of this is incomplete because of limitations in the technical approaches available to study platelets of different ages. In this study, we have developed and validated an in vivo temporal labeling approach using injectable fluorescent antiplatelet antibodies to subdivide platelets by age and assess differences in functional and molecular characteristics. With this approach, we found that young platelets (<24 hours old) in comparison with older platelets respond to stimuli with greater calcium flux and degranulation and contribute more to the formation of thrombi in vitro and in vivo. Sequential sampling confirmed this altered functionality to be independent of platelet size, with distribution of sizes of tracked platelets commensurate with the global platelet population throughout their 5-day lifespan in the circulation. The age-associated decrease in thrombotic function was accompanied by significant decreases in the surface expression of GPVI and CD31 (PECAM-1) and an increase in CD9. Platelet messenger RNA (mRNA) content also decreased with age but at different rates for individual mRNAs indicating apparent conservation of those encoding granule proteins. Our pulse-chase-type approach to define circulating platelet age has allowed timely reexamination of commonly held beliefs regarding size and reactivity of young platelets while providing novel insights into the temporal regulation of receptor and protein expression. Overall, future application of this validated tool will inform age-based platelet heterogeneity in physiology and disease.

Comparison of the value of immature retyculocyte and immature platelet in the diagnosıs of sepsis

BACKGROUND

Sepsis is one of the causes of pre-treatment morbidity and mortality in the pediatric age group. In the present study, we investigated the place of the immature granulocyte percentage, (IG) immature reticulocyte fraction (IRF), and immature platelet fraction (IPF) in the diagnosis of sepsis.

METHODS

Complete blood count, C-reactive protein, (CRP) procalcitonin (PCT) and blood cultures were measured in 125 critical patients who were followed-up in the intensive care unit with the suspicion of sepsis and 65 healthy children between 2017 and 2019. In addition to the complete blood counts and routine parameters, IG, IRF, and IPF were examined in the patients.

RESULTS

When the critical patient group and the healthy control group were compared, it was found that the total number of leukocytes (white blood cells), neutrophil count, platelet count, CRP, PCT, IG, IRF, and IPF values were higher at statistically significant levels. When septic and non-septic patients were compared, it was found that the CRP, PCT,IGP, and IPF were higher at statistically significant levels in the septic patients.

CONCLUSIONS

It was concluded that CRP, PCT, IG, and IPF were significant in determining sepsis and that PCT was the most sensitive and specific biomarker in these parameters. We believe that these parameters may be suitable for practical use in determining sepsis because they give faster results and suggest the diagnosis of sepsis.

Impact of uric acid on immature platelet fraction in patients undergoing percutaneous coronary intervention

INTRODUCTION

Reticulated platelets have been involved in the pathophysiology of coronary artery disease (CAD). Immature platelet fraction (IPF) allows their measurement in daily clinical practice, although the factors conditioning their elevation are still largely unexplored. Serum uric acid (SUA) is the end product of purine metabolism, displaying a pro-oxidant and pro-inflammatory action and increasing the cardiovascular risk. The aim of our study was to investigate the impact of SUA on IPF levels in patients undergoing percutaneous coronary intervention (PCI), and their relationship with CAD.

METHODS

We enrolled a cohort of consecutive patients undergoing coronary angiography in a single center. Hyperuricemia was defined by SUA ≥ 6.5 mg/dl. Significant CAD was defined as at least 1 vessel stenosis >50%, while severe CAD was defined as left main and/or three-vessel disease. IPF was measured at admission by routine blood cells count (A Sysmex XE-2100).

RESULTS

We included in our study 2217 patients, of whom 544 had high levels of SUA, while 1673 had normal levels. Hyperuricemics were older, with higher percentage of renal failure, hypertension, dilated cardiomyopathy or valvular disease as indication to angiography, higher levels of creatinine and C-reactive protein (p < 0.001, respectively) when compared to normouricemics. Immature platelet fraction (IPF) was significant higher in hyperuricemic patients (3.96% vs 3.59%, p = 0.004). A progressive direct increase in the IPF values was observed in relation to SUA levels (r = 0.101, p < 0.001), although at multivariate analysis, hyperuricemia did not result as an independent predictor of IPC in 3rd tertile (adjusted OR [95%CI] = 1.21 [0.85-1.71] P = 0.288). When stratifying hyperuricemics and normouricemics according to IPF tertiles (<2.3%; 2.3-3.9%; ≥ 4%), reticulated platelets were not associated to the prevalence of CAD (SUA ≥6.5:80.9 vs 79.3% vs 78.6%, p = 0.60; SUA < 6.5: 79.3% vs 81.3% vs 78.9%, p = 0.878) or severe CAD (SUA ≥6.5: 34.9% vs 38.9% vs 35.2%, p = 0.99; SUA < 6.5: 30.4% vs 33.5% vs 34%, p = 0.192), and the results were confirmed at multivariate analysis for CAD (SUA ≥6.5: adjusted OR [95%CI] = 1.11 [0.81-1.51] P = 0.524, SUA < 6.5: adjusted OR [95%CI] = 0.89 [0.75-1.05] P = 0.170) or severe CAD (SUA ≥6.5: adjusted OR [95%CI] = 1.03 [0.81-1.31] P = 0.795; SUA < 6.5: adjusted OR [95%CI] = 1.10 [0.96-1.26] P = 0.192).

CONCLUSIONS

In the present study we found a direct relationship between SUA levels and IPF values; however, hyperuricemia did not result as an independent predictor of higher IPF tertile values. Neither in hyperuricemics nor in normouricemics higher IPF were independently associated to the prevalence of CAD or severe CAD.

Effects of Time-Interval since Blood Draw and of Anticoagulation on Platelet Testing (Count, Indices and Impedance Aggregometry): A Systematic Study with Blood from Healthy Volunteers

Platelet count, indices (mean volume, young-immature platelet fraction) and aggregation are widely used laboratory parameters to investigate primary hemostasis. We performed a systematic, thorough evaluation of the influence of the time-interval since blood draw from 20 healthy individuals and of the anticoagulation of collected blood on such parameters. Blood was anticoagulated with citrate, K₂-ethylenediaminetetraacetic acid (EDTA) and hirudin and analyzed 5, 30, 60, 120 and 180 min after blood draw. Multiple electrode aggregometry (MEA) was performed with either hirudin (half-diluted with NaCl) or citrate samples (half-diluted with NaCl or CaCl₂ 3 mM). Platelet count and indices (Sysmex XN-20) were rather stable over time with EDTA blood. MEA results were lower with citrate blood than with hirudin blood; supplementation with calcium was partially compensatory. MEA results were also lower when performed less than 30 or more than 120 min after blood draw. Platelet clumping, quantitatively estimated with microscope examination of blood smears, was more important in hirudin blood than citrate or EDTA blood and could explain some of the differences observed between preanalytical variables. The results stress once more the importance of preanalytical variables in hemostasis laboratory testing. Decision thresholds based on those tests are only applicable within specific preanalytical conditions.

Platelet "-omics" in health and cardiovascular disease

The importance of platelets for cardiovascular disease was established as early as the 19th century. Their therapeutic inhibition stands alongside the biggest achievements in medicine. Still, certain aspects of platelet pathophysiology remain unclear. This includes platelet resistance to antiplatelet therapy and the contribution of platelets to vascular remodelling and extends beyond cardiovascular disease to haematological disorders and cancer. To address these gaps in our knowledge, a better understanding of the underlying molecular processes is needed. This will be enabled by technologies that capture dysregulated molecular processes and can integrate them into a broader network of biological systems. The advent of -omics technologies, such as mass spectrometry proteomics, metabolomics and lipidomics; highly multiplexed affinity-based proteomics; microarray- or RNA-sequencing-(RNA-seq)-based transcriptomics, and most recently ribosome footprint-based translatomics, has enabled a more holistic understanding of platelet biology. Most of these methods have already been applied to platelets, and this review will summarise this information and discuss future developments in this area of research.

Impact of diabetes mellitus on immature platelet fraction and its association with coronary artery disease

BACKGROUND

Higher prothrombotic status and alterations in platelet function and thrombopoiesis are associated with diabetes mellitus (DM). We assessed the impact of diabetes and glucose control on the immature platelet fraction (IPF) and their relationship with prevalence and extent of coronary artery disease (CAD).

METHODS

Consecutive patients undergoing coronary angiography were included. Significant CAD was defined as at least one vessel stenosis greater than 50%. IPF levels were measured at admission by routine blood cells count (A Sysmex XE-2100).

RESULTS

We included 1781 patients, of whom 660 (37.1%) suffered from diabetes. Diabetes was associated with advanced age and a higher cardiovascular risk profile. No difference in the mean values of IPF were observed between patients with or without DM (3.6 ± 2.5 vs 3.5 ± 2.5, P = 0.39) and neither in the rate of patients with IPF above the median (2.9%) (51.6% vs 50.6%, P = 0.73). In patients with DM, the IPF levels did not relate with glucose control parameters (glycaemia: r = -0.024, P = 0.54, glycosylated haemoglobin: r = 0.11, P = 0.72). The prevalence of CAD was significantly lower in patients with DM and IPF greater than the median (80.5% vs 86.5%, P = 0.04, adjusted odds ratio [OR] [95% confidence interval {CI}] = 0.57[0.36-0.91], P = 0.02), while not left main/three-vessel CAD (36.9% vs 38.2%, P = 0.75, adjusted OR [95%CI] = 0.91[0.64-1.28], P = 0.90).

CONCLUSION

In the present study, neither DM nor glucose control are independent predictors of IPF above the median. In patients with DM, higher IPF levels were associated with a lower prevalence of CAD and with a similar extent of severe CAD and angiographic findings. Therefore, until new data become available, elevated IPF should not be systematically applied on a large scale as cardiovascular risk marker in patients with diabetes.

Impact of aging on platelet reactivity in diabetic patients receiving dual antiplatelet therapy

Advanced age and diabetes represent summative conditions in the determination of cardiovascular risk, and especially for the management of dual antiplatelet therapy (DAPT), often requiring balancing between bleeding and thrombotic complications. However, few studies have so far evaluated the impact of age on platelet reactivity and suboptimal platelet inhibition (high-on treatment platelet reactivity-HRPR) on DAPT among diabetic patients, that was, therefore the aim of the present study. In diabetic patients treated with DAPT (ASA + clopidogrel or ticagrelor) platelet reactivity was assessed at 30-90 days post-discharge for an acute coronary syndrome or elective PCI. Aggregation was assessed by multiple-electrode aggregometry. HRPR was defined for values above the lower limit of normality (in non-treated patients). Elderly patients were considered ≥ 75 years of age. We included 462 patients, among them 149 (32.2%) were ≥ 75 years. Elderly patients were more often females (p = 0.006), with lower body size (p = 0.04), acute coronary syndrome at presentation and renal failure (p < 0.001), non-smokers (p = 0.002), in therapy with insulin (p = 0.02) and diuretics (p < 0.001) and lower rate of betablockers (p = 0.02). Age directly related with C reactive protein (p = 0.01), creatinine levels and inversely with hemoglobin (p < 0.001) and triglycerides (p = 0.003). No association was found at linear regression analysis for platelet reactivity and age with different activating stimuli, but for ASPI test (r = 0.12; p = 0.03). No significant difference in HAPR was found in elderly patients (2.4 vs. 3.2%, p = 0.76, OR[95% CI] = 0.45[0.1-2.11], p = 0.31). HRPR for ADP antagonists was similarly not affected by age (30.1% vs. 35.7%, p = 0.28, adjusted OR[95% CI] = 0.78[0.47-1.29], p = 0.33). Comparable results were obtained when considering separately the DAPT strategies with clopidogrel or ticagrelor, or when adjusting our results according to propensity score values. Among diabetic patients receiving dual antiplatelet therapy for an acute coronary syndrome or elective percutaneous coronary intervention, age does not affect platelet reactivity or the rate of high-on treatment platelet reactivity. Similar results were obtained for ASA and clopidogrel or ticagrelor.

Reticulated platelets – clinical application and future perspectives

Reticulated platelets are immature platelets freshly released from the bone marrow into the circulation and contain vestigial amounts of ribonucleic acid. Thus, they can serve as an indicator for the activity of thrombopoiesis. Despite the current lack of a standardized reference method, two types of hematology analyzers have incorporated a fully automated measurement of reticulated platelets. The “immature platelet fraction” (IPF; Sysmex XE-/XN-series) has some clinical utility in the differential diagnosis of thrombocytopenia. This is less clear for “reticulated platelets” (retPLT; Abbott CELL-DYN Sapphire/Alinity HQ). The usefulness of these parameters in the prediction of platelet recovery after chemotherapy or stem cell transplantation and as a decision aid for platelet transfusions has not been unequivocally confirmed. Recent findings have shown an association of reticulated platelets with an adverse risk in patients with coronary artery disease and stroke as well as resistance to anti-platelet therapy. Furthermore, a role of reticulated platelets for the prediction of sepsis was indicated. However, validation in larger prospective trials is necessary to establish the clinical benefit of reticulated platelets in these conditions. This review gives an overview of the available analytical methods and summarizes the current knowledge regarding the clinical application of reticulated platelets.

Impact of aging on immature platelet count and its relationship with coronary artery disease

Despite the fact that elderly patients represent a prevalent and challenging population in the current practice, few data exist on the impact of platelet parameters on cardiovascular risk in these patients. Therefore, the aim of the present study was to evaluate the impact of age on the immature platelet count (IPC) and their relationship with CAD. We included a total of 2236 consecutive patients undergoing coronary angiography in a single center. Elderly patients (age ≥ 75 years) were 756 (33.7%). IPC was measured at admission. Elderly patients were more often females (p < .001), with lower BMI and prevalence of smokers (p < .001), and a more complex cardiovascular risk profile and coronary disease (p = .02). Platelet count decreased with aging (p = .05), whereas no difference in the mean IPC was found between patients < or ≥75 years. In fact, advanced age did not emerge as an independent predictor of IPC above III tertile (≥8.6*10^6/ml), (adjusted OR[95%CI] = 0.97[0.78-1.21], p = .79). When considering elderly patients according to tertiles values of IPC (<5.1,5.1-8.59; ≥8.6*10^6/ml), we found no impact of IPC on the prevalence of CAD (81.1% vs 84.5% vs 81.5%, p = .92; adjusted OR[95%CI] = 1.08[0.67-1.72], p = .75) and its extent (37.7% vs 34.5% vs 40.2%, p = .57; adjusted OR[95%CI] = 1.22[0.85-1.73], p = .28). However, we observed a higher rate of calcified and type C lesions in elderly patients with higher IPC (p = .03 and p < .001, respectively). Therefore, advanced age is not associated with higher immature platelet count and the prevalence and severity of CAD. Moreover, IPC does not contribute to explain the higher prevalence and extent of coronary artery disease observed in elderly patients.

Prognostic significance of reticulated platelet levels in diabetic patients with stable coronary artery disease

Levels of reticulated platelets (RP) increase during high platelet turnover conditions, and have been shown to correlate with diabetes mellitus (DM) status. Little is known regarding the prognostic significance of levels of RP among patients with stable coronary artery disease (SCAD). The study consisted of patients with SCAD and DM, who visited our cardiology outpatient clinic between June 2016 and February 2017. RP levels were measured at baseline as immature platelet fraction (IPF)%, using flow cytometry. Outcomes at 2 years consisted of bleeding events and major adverse cardiovascular events (MACE), which included death, myocardial infarction, cerebrovascular accident and urgent revascularization. The study included 104 patients (mean age - 71.2 ± 9.5 years, 76.9% were male, and 83.7% had hypertension). IPF was significantly higher at baseline among patients who had suffered from a MACE (4.57% vs. 2.53%, p < .001), and lower in patients who had suffered from bleeding events, compared with those who had not (1.57% vs. 3.00%, p = .004). There were higher rates of MACE at higher IPF quartiles (p < .001, AUC-0.770), and higher rates of bleeding at the lowest quartiles (p = .007, AUC-0.781). In SCAD patients with DM, levels of RP are associated with a higher risk of MACE, and inversely correlated with the risk of bleeding.

Influence of antiretroviral therapy and cardiovascular disease on the immature platelet fraction in patients living with HIV

Cardiovascular disease is an important contributor to morbidity and mortality in people living with HIV . The immature platelet fraction (IPF) is increased in HIV-negative patients with cardiovascular disease and evidence suggests that an enlarged IPF is associated with adverse cardiovascular events. In this multi-center observational study, we aimed to investigate how the IPF in people living with HIV is influenced by antiretroviral therapy and cardiovascular disease. Subjects without cardiovascular disease that received antiretroviral therapy showed a smaller IPF accompanied by lower D-dimer and C-reactive protein (CRP) levels compared to therapy-naïve subjects (mean IPF: 2.9% vs. 3.9%, p = .016; median D-dimer: 252 µg/L vs. 623 µg/L, p < .001; median CRP: 0.2 mg/dL vs. 0.5 mg/dL, p = .004). No significant differences for the IPF, D-dimer or CRP were found between subjects on antiretroviral therapy with documented cardiovascular disease and therapy-naïve subjects. In conclusion, we observed a reduction in the IPF among subjects on therapy only in the absence of cardiovascular disease. In contrast, subjects receiving therapy that had documented cardiovascular disease showed an IPF comparable to therapy-naïve subjects. Future studies are needed to investigate if an enlarged IPF may serve as a biomarker in predicting adverse cardiovascular events in people living with HIV.

Effects of statin therapy on mean platelet volume in patients with risk of cardiovascular diseases: a systematic review and meta-analysis

Many studies have demonstrated the effects of statin therapy on platelet, but it is controversial that whether statin could reduce mean platelet volume (MPV) in patients with the risk of cardiovascular diseases. To further improve the clinical significance of MPV in those patients and explore new function of statin, we conducted this research. Relevant studies were selected by searching electronic databases (PubMed, Embase and Cochrane Library) and reference lists of related articles by hand. Two reviewers independently assessed eligibility and quality of the studies. Eventually, we included ten studies, a total of 1189 patients with the risk of cardiovascular diseases. Consolidating relevant data and comparing the changes of MPV before and after statin treatment, we found that statin could decrease MPV [standard mean difference (SMD) = −0.47 (−0.71–0.23)], which was statistically significant (P=0.0001). Subgroup analysis suggested that when ≥55 years, this decrease did not occur [SMD = −0.06 (−0.18, 0.06)]. Drug type, sample size, ethnicity, mean age and quality of included article were sources of heterogeneity. Therefore, statin therapy could reduce MPV significantly and exhibited antiplatelet activity, which is of great importance in clarifying the clinical significance of MPV in cardiovascular events and the prevention of cardiovascular events.

Association between serum magnesium and blood count: influence of type 2 diabetes and central obesity

The relationship between serum Mg and blood cell counts in Chinese adult diabetes or central obesity was assessed by investigating 8163 subjects with China Health and Nutrition Survey (mean age 59⋅6 years, 54⋅9 % men). Participants were classified according to blood Mg (below 0⋅65 mmol/l, or 0⋅66–0⋅94 mmol/l or above 0⋅95 mmol/l), type 2 diabetes (yes/no) and central obesity (yes/no). Leucocytes, erythrocytes, platelets (PLT), Hb and glycated Hb (HbA1c) were determined using standardised methods and conditions. HbAc1, leucocytes and PLT were significantly higher among subjects with central obesity than without central obesity (P &lt; 0⋅05). A significant increase for Hb, erythrocytes, PLT, but not leucocytes, across progressive Mg groups was observed in subjects without diabetes (P &lt; 0⋅05). Hb, erythrocytes and HbAc1 were significantly higher among subjects with higher Mg than in subjects with lower Mg with diabetes (P &lt; 0⋅05). Central obesity disturbed the positive association between PLT count and serum Mg. Type 2 diabetes caused metabolism disorder in serum Mg, blood sugar and blood cell count. Hb, erythrocytes and PLT, but not leucocytes, are positively correlated with serum Mg, but this association is somehow disturbed by type 2 diabetes or central obesity.

Platelets volume indexes and cardiovascular risk factors

Obesity, diabetes and hypertension are risk factors for cardiovascular diseases (CVD) because they promote a state of hypercoagulability. It is known that platelets play an important role in the development of atherosclerosis. Recent studies have evaluated platelet volume indexes (PVIs) in individuals with risk factors for CVD to better understand the platelet mechanisms involved in their development. The IVPs indirectly estimate platelet function and are easily obtained from automated hematology analyzers, which provide platelet counts, mean platelet volume (MPV), platelet distribution width (PDW) and the platelet-large cell ratio (P-LCR). The present study aims to review literature studies that investigated the association between PVIs and obesity, diabetes, and arterial hypertension, in order to evaluate its use as a potential subclinical marker of CVD. Studies have shown promising results for MPV, an index that allows for early detection of platelet activation and may be useful in identifying patients before the onset of CVD development so that preventive strategies can be implemented. The PDW, although evaluated by a smaller number of studies, also showed promising results. However, there is still a long way to go in order for the MPV and PDW to be used in clinical practice, since there is still a need for more epidemiological evidence, establishing reference values, and standardizing the way results are presented.

Relationship between mean platelet volume and metabolic syndrome in Chinese patients

Mean platelet volume (MPV) is a determinant of activation and variability of platelets (PLT). The focus of this study was to to investigate MPV values in patients with and without metabolic syndrome (MS). It also evaluates the association between them. There are close connections among MPV, MS, and cardiometabolic risk. We compiled age, body mass index, blood cell counts, MPV, and other data of 59976 self-reported healthy volunteers (28428 male, 31548 female), 24.65% of who have MS. The mean age of the group was 48.21 years old. The data was grouped by sex and values of data between men and women groups were analyzed by independent sample’s t-test. The relationship between sex and MS was evaluated by chi-square tests. Crude odd ratios of MS between MPV quartiles and 95% confidence intervals were analyzed by binary logistic regression in this study. We found women had higher levels of MPV (10.09 vs. 9.98, P < 0.01) and PLT (228.68 vs. 212.11, P < 0.01) than men. In females, the prevalence of MS was higher in low MPV group than in high MPV groups. The odds of having MS were significantly lower in higher MPV quartiles compared with MPV Quartile 1 in women (Adjusted OR < 1, P < 0.01). This study indicated that MS was inversely associated with MPV in females only.

The Relationship Between Mean Platelet Volume and Fasting Plasma Glucose and HbA1c Levels in a Large Cohort of Unselected Health Check-Up Participants

Background

Larger platelets are more active and mean platelet volume (MPV) is an indicator of platelet activation and an independent risk factor of cardiovascular diseases. While MPV is reported to be higher in diabetic patients, the relationship between MPV and glycemic parameters in general population remains inconclusive.

Methods

In this cross-sectional study, we studied relationship between MPV and fasting plasma glucose (FPG) and HbA1c levels in 38,204 unselected participants of general health check-up aged 20 years or older in the year of 2014 who were considered to be representative of the general population. Individuals with known diabetes, coronary artery disease and/or cerebrovascular disease who were on drug therapy and those with platelet counts below 100 × 10⁹/L or above 400 × 10⁹/L were excluded.

Results

The mean age of the individuals was 52.3 ± 12.1 years and 46.1% were male. There were positive associations between MPV and both FPG (r = 0.066; P < 0.001) and HbA1c (r = 0.025; P < 0.001) levels when all individuals were analyzed as a whole. While the association was only marginal in individuals with HbA1c levels below 6.5% (r = 0.009; P = 0.068), it was significant in those with HbA1c ≥ 6.5% (r = 0.138; P < 0.001). When the individuals were categorized into four groups according to the HbA1c values: HbA1c < 5.5%, 5.5% ≤ HbA1c < 6.0%, 6.0% ≤ HbA1c < 6.5%, and HbA1c ≥ 6.5%, the mean MPV was virtually same among groups with HbA1c level < 6.5% and that of the individuals with HbA1c ≥ 6.5 was significantly higher than groups with lower HbA1c levels. Multivariate analyses adjusted with age and sex showed the same results.

Conclusion

FPG and HbA1c appeared to be associated with MPV in unselected health check-up participants; however, the association between glycemic state and MPV was apparent only in individuals with impaired glycemic control and only marginal in those with normal glycemic control. The clinical significance of the associations warrants further study.

Platelet indices and glucose control in type 1 and type 2 diabetes mellitus: A case-control study

BACKGROUND AND AIMS

The relationship between platelet indices and glucose control may differ in type 1 (T1DM) and type 2 (T2DM) diabetes. We aimed to investigate differences in mean platelet volume (MPV), platelet count, and platelet mass between patients with T1DM, T2DM, and healthy controls and to explore associations between these platelet indices and glucose control.

METHODS AND RESULTS

A total of 691 T1DM and 459 T2DM patients and 943 control subjects (blood donors) were included. HbA1c was measured in all subjects with diabetes and 36 T1DM patients further underwent 24 h-continuous glucose monitoring to estimate short-term glucose control (glucose mean and standard deviation). Adjusting for age and sex, platelet count was higher and MPV lower in both T1DM and T2DM patients vs control subjects, while platelet mass (MPV × platelet count) resulted higher only in T2DM. Upon further adjustment for HbA1c, differences in platelet count and mass were respectively 19.5 × 10⁹/L (95%CI: 9.8-29.3; p < 0.001) and 101 fL/nL (12-191; p = 0.027) comparing T2DM vs T1DM patients. MPV and platelet count were significantly and differently related in T2DM patients vs both T1DM and control subjects; this difference was maintained also accounting for HbA1c, age, and sex. Platelet mass and the volume-count relationship were significantly related to HbA1c only in T1DM patients. No associations were found between platelet indices and short-term glucose control.

CONCLUSION

By accounting for confounders and glucose control, our data evidenced higher platelet mass and different volume-count kinetics in subjects with T2DM vs T1DM. Long-term glucose control seemed to influence platelet mass and the volume-count relationship only in T1DM subjects. These findings suggest different mechanisms behind platelet formation in T1DM and T2DM patients with long-term glycaemic control being more relevant in T1DM than T2DM.

Aspirin in the prevention of cardiovascular events in patients with diabetes

Diabetes imparts a substantial increased risk for cardiovascular disease-related mortality and morbidity. Because of this, current medical guidelines recommend prophylactic treatment with once-daily, low-dose aspirin (acetylsalicylic acid) for primary and secondary prevention of cardiovascular (CV) events in high-risk patients. However, only modest reductions in CV events and mortality have been observed with once-daily aspirin treatment in patients with diabetes, including patients with a previous CV event, perhaps because of disparity between aspirin pharmacokinetics and diabetes-related platelet abnormalities. Once-daily aspirin irreversibly inactivates platelets for only a short duration (acetylsalicylic acid half-life, approximately 15-20 minutes), after which time newly generated, active platelets enter the circulation and weaken aspirin's effect. Platelets from patients with diabetes are more reactive and are turned over more rapidly than platelets from normal individuals; the short inhibitory window provided by once-daily aspirin may therefore be insufficient to provide 24-h protection against CV events. Alternative conventional aspirin regimens (e.g. higher daily dose, twice-daily dosing, combination with clopidogrel) and newer formulations (e.g. 24-h, extended-release) have been proposed to overcome the apparent limited efficacy of conventional aspirin in patients with diabetes; however, tolerability concerns and limited clinical efficacy data need to be taken into account when considering the use of such regimens.

Drug delivery and therapeutic impact of extended-release acetylsalicylic acid

Current treatment guidelines recommend once-daily, low-dose acetylsalicylic acid (ASA; aspirin) for secondary prevention of cardiovascular events. However, the anti-thrombotic benefits of traditional ASA formulations may not extend over a 24-h period, especially in patients at high risk for a recurrent cardiovascular event. A next-generation, extended-release ASA formulation (ER-ASA) has been developed to provide 24-h anti-thrombotic coverage with once-daily dosing. The pharmacokinetics of ER-ASA indicates slower absorption and prolonged ASA release versus immediate-release ASA, with a favorable safety profile. ER-ASA minimizes systemic ASA absorption and provides sustained antiplatelet effects over a 24-h period.

The Influence of Haemoglobin A1c Levels on Platelet Aggregation and Platelet Turnover in Patients with Coronary Artery Disease Treated with Aspirin

Background

Hyperglycaemia may attenuate the antiplatelet effect of aspirin and thereby increase the risk of cardiovascular events. We investigated the influence of increased haemoglobin A1c (HbA1c) levels on platelet aggregation and turnover in a large cohort of patients with coronary artery disease (CAD) with type 2 diabetes, prediabetes or no diabetes.

Methods

In this observational study, we included 865 stable CAD patients on 75 mg aspirin as mono-therapy of whom 242 patients had type 2 diabetes and were receiving antidiabetic drugs. Among 623 patients without diabetes, we classified 303 patients with prediabetes (HbA1c ≥5.7–6.4% [39–47 mmol/mol]) naive to antidiabetic drugs. Platelet aggregation was evaluated by the Multiplate Analyzer using arachidonic acid and collagen and by the VerifyNow Aspirin. Platelet turnover was evaluated by immature platelets using flow cytometry and platelet activation by soluble P-selectin.

Results

CAD patients with type 2 diabetes had higher platelet aggregation (all p-values <0.01), platelet turnover (immature platelet count, p<0.01) and platelet activation (p<0.001) than patients without diabetes. CAD patients with prediabetes had increased platelet aggregation (p = 0.02) and platelet count (p = 0.02) compared with patients without diabetes. Increased levels of HbA1c correlated positively with increased platelet aggregation using arachidonic acid (r = 0.19, p<0.0001), collagen (r = 0.10, p<0.01) and VerifyNow (r = 0.15, p<0.0001), and with platelet count (r = 0.08, p = 0.01), immature platelet count (r = 0.11, p<0.001) and soluble P-selectin (r = 0.15, p<0.0001). These associations were mainly evident in non-diabetic and prediabetic CAD patients.

Conclusions

CAD patients with prediabetes and diabetes may have attenuated antiplatelet effect of aspirin compared with CAD patients without diabetes. This may be related to increased platelet count in patients with prediabetes. Increased levels of HbA1c correlated positively, though weakly, with increased platelet aggregation, platelet turnover and platelet activation.

The mean platelet volume is significantly associated with higher glycated hemoglobin in a large population of unselected outpatients

AIMS

To examine the association between mean platelet volume (MPV) and glycated hemoglobin (HbA1c) in a large cohort of unselected outpatients.

METHODS

We retrospectively reviewed combined results of complete blood count (CBC) and hemoglobin A1c (HbA1c) performed in all outpatients aged 18 years or older, who were referred to the outpatient clinic of our hospital for routine health check-up during the year 2013.

RESULTS

Cumulative results of both CBC and HbA1c could be retrieved for 4072 male and female outpatients aged 18 years or older. There were significant associations between HbA1c and both MPV (r=0.10; p<0.001) and platelet count (r=0.05; p<0.001), that remained statistically significant after adjusting for age and sex. After stratifying the whole sample of patients for MPV quartiles, there was a significant, positive trend of HbA1c across quartiles of MPV (p<0.001). Similar findings were found when the whole sample was stratified by clinical thresholds of HbA1c (p<0.001), with values of MPV gradually increasing from subjects with normal glucose homeostasis, pre-diabetes and diabetes.

CONCLUSIONS

The results of our investigation, which is supposed to be the largest cohort study on unselected outpatients assessing the relationship between HbA1c and platelets number or size, indicate that elevated MPV is significantly associated with higher HbA1c levels and vice versa.

Platelet mean volume, distribution width, and count in type 2 diabetes, impaired fasting glucose, and metabolic syndrome: a meta-analysis

BACKGROUND

Platelet activation contributes to cardiovascular disease (CVD), the main complication of type 2 diabetes mellitus (T2DM) and pre-diabetic conditions. Mean platelet volume is an easy-to-measure platelet parameter that has been associated with CVD. We sought to assess mean platelet volume, platelet distribution width, and platelet count in T2DM, impaired fasting glucose (IFG), impaired glucose tolerance (IGT), and metabolic syndrome.

METHODS

Web-based literature search (PubMed, EMBASE, and Web of Science) of studies published in English through June 2014 was performed to select case-control and cross-sectional studies that reported data on mean platelet volume, platelet distribution width, or platelet count in cases (subjects with T2DM, IFG, IGT, or metabolic syndrome) and noncases. Descriptive and quantitative information was extracted, and within-study standardized mean difference was estimated from means and standard deviations. Standardized mean differences across studies were synthesized using a random random-effects model, and subgroup analyses were performed on pre-specified study-level characteristics.

RESULTS

Thirty-nine studies were included. Compared with controls, mean platelet volume was significantly higher in T2DM (standardized mean difference, 95% confidence interval: 0.70, 0.50-0.91; N = 24,245), IFG (0.14, 0.02-0.26; N = 17,389) but not in metabolic syndrome (0.15, -0.24 to 0.55; N = 14,990). Platelet distribution width was wider in T2DM (0.93, 0.09-1.76; N = 471). Platelet count resulted higher in IFG (0.18, 0.12-0.24; N = 3960) and metabolic syndrome (0.39, 0.01-0.78; N = 4070). Only two studies included IGT.

CONCLUSIONS

Available data suggest that T2DM subjects tend to have higher mean platelet volume and platelet distribution width values, but nondifferent platelet count as compared with subjects without T2DM. Whether and how these morphometric changes contribute to CVD of T2DM or can be used as CVD biomarker awaits further investigation.

Association of the immature platelet fraction with sepsis diagnosis and severity

Management of Sepsis would greatly benefit from the incorporation of simple and informative new biomarkers in clinical practice. Ideally, a sepsis biomarker should segregate infected from non-infected patients, provide information about prognosis and organ-specific damage, and be accessible to most healthcare services. The immature platelet fraction (IPF) and immature reticulocyte fraction (IRF) are new analytical parameters of the complete blood count, that have been studied as biomarkers of several inflammatory conditions. Recently, a study performed in critically-ill patients suggested that IPF could be a more accurate sepsis biomarker than C-reactive protein (CRP) and procalcitonin. In this retrospective study we evaluated the performance of IPF and IRF as biomarkers of sepsis diagnosis and severity. 41 patients admitted to two intensive care units were evaluated, 12 of which with severe sepsis or septic shock, and 11 with non-complicated sepsis. Significantly higher IPF levels were observed in patients with severe sepsis/septic shock. IPF correlated with sepsis severity scores and presented the highest diagnostic accuracy for the presence of sepsis of all studied clinical and laboratory parameters. No significant differences were observed in IRF levels. Our results suggest that IPF levels could be used as a biomarker of sepsis diagnosis and severity.