Platelet activation patterns in platelet size sub-populations: differential responses to aspirin in vitro

Heterogeneity of platelets and their responses

There has been increasing recognition of heterogeneity in blood platelets and their responses, particularly in recent years, where next-generation technologies and advanced bioinformatic tools that interrogate "big data" have enabled large-scale studies of RNA and protein expression across a growing list of disease states. However, pioneering platelet biologists and clinicians were already hypothesizing upon and investigating heterogeneity in platelet (and megakaryocyte) activity and platelet metabolism and aggregation over half a century ago. Building on their foundational hypotheses, in particular Professor Marian A. Packham's pioneering work and a State of the Art lecture in her memoriam at the 2023 International Society on Thrombosis and Haemostasis Congress by Anandi Krishnan, this review outlines the key features that contribute to the heterogeneity of platelets between and within individuals. Starting with important epidemiologic factors, we move stepwise through successively smaller scales down to heterogeneity revealed by single-cell technologies in health and disease. We hope that this overview will urge future scientific and clinical studies to recognize and account for heterogeneity of platelets and aim to apply methods that capture that heterogeneity. Finally, we summarize other exciting new data presented on this topic at the 2023 International Society on Thrombosis and Haemostasis Congress.

Is dynamic change in mean platelet volume related with composite endpoint development after transcatheter aortic valve replacement?

Aortic valve stenosis (AS) is the most common valvular disease, and surgical or transcatheter aortic valve replacement (TAVR) are the treatment options. Diminish in platelet production or dysfunction may occur due to shear stress, advanced age, and other coexisting diseases in AS patients. Bleeding is one of the complications of TAVR and associated with increased mortality. MPV (mean platelet volume) indicates platelet's thrombogenic activity. Overproduction or consumption of platelets in various cardiac conditions may affect MPV values. We aimed to investigate the pre and postprocedure MPV percentage change (MPV-PC) and its association with post-TAVR short-term complications. A total of 204 patients who underwent TAVR with a diagnosis of severe symptomatic AS were included. The mean age was 78.66 ± 6.45 years, and 49.5% of patients were women. Two groups generated according to composite end point (CEP) development: CEP(+) and CEP(-).110 patients(53.9%) formed CEP(+) group. Although baseline MPV and platelet levels were similar between groups, MPV was increased ( P  < 0.001) and platelet was decreased ( P  < 0.001) significantly following the procedure when compared to baseline. MPV-PC was significantly higher in the VARC type 2-4 bleeding ( P   =  0.036) and major vascular, access-related, or cardiac structural complication groups ( P   =  0.048) when CEP subgroups were analyzed individually. Regression analysis revealed that diabetes mellitus [ P   =  0.044, β: 1.806 odds ratio (95% confidence interval): 1.016-3.21] and MPV-PC [ P   =  0.007,β: 1.044 odds ratio (95% confidence interval): 1.012-1.077] as independent predictors of CEP development at 1 month after TAVR. The MPV increase following TAVR may be an indicator of adverse outcomes following TAVR procedure within 1-month.

Interactions of platelets with obesity in relation to lung cancer risk in the UK Biobank cohort

BACKGROUND

Platelet count (PLT) is associated positively with lung cancer risk but has a more complex association with body mass index (BMI), positive only in women (mainly never smokers) and inverse in men (mainly ever smokers), raising the question whether platelets interact with obesity in relation to lung cancer risk. Prospective associations of platelet size (an index of platelet maturity and activity) with lung cancer risk are unclear.

METHODS

We examined the associations of PLT, mean platelet volume (MPV), and platelet distribution width (PDW) (each individually, per one standard deviation increase) with lung cancer risk in UK Biobank men and women using multivariable Cox proportional hazards models adjusted for BMI and covariates. We calculated Relative Excess Risk from Interaction (RERI) with obese (BMI ≥ 30 kg/m2), dichotomising platelet parameters at ≥ median (sex-specific), and multiplicative interactions with BMI (continuous scale). We examined heterogeneity according to smoking status (never, former, current smoker) and antiaggregant/anticoagulant use (no/yes).

RESULTS

During a mean follow-up of 10.4 years, 1620 lung cancers were ascertained in 192,355 men and 1495 lung cancers in 218,761 women. PLT was associated positively with lung cancer risk in men (hazard ratio HR = 1.14; 95% confidence interval (CI): 1.09-1.20) and women (HR = 1.09; 95%CI: 1.03-1.15) but interacted inversely with BMI only in men (RERI = - 0.53; 95%CI: - 0.80 to - 0.26 for high-PLT-obese; HR = 0.92; 95%CI = 0.88-0.96 for PLT*BMI). Only in men, MPV was associated inversely with lung cancer risk (HR = 0.95; 95%CI: 0.90-0.99) and interacted positively with BMI (RERI = 0.27; 95%CI = 0.09-0.45 for high-MPV-obese; HR = 1.08; 95%CI = 1.04-1.13 for MPV*BMI), while PDW was associated positively (HR = 1.05; 95%CI: 1.00-1.10), with no evidence for interactions. The associations with PLT were consistent by smoking status, but MPV was associated inversely only in current smokers and PDW positively only in never/former smokers. The interactions with BMI were retained for at least eight years of follow-up and were consistent by smoking status but were attenuated in antiaggregant/anticoagulant users.

CONCLUSIONS

In men, PLT was associated positively and MPV inversely with lung cancer risk and these associations appeared hindered by obesity. In women, only PLT was associated positively, with little evidence for interaction with obesity.

High Autophagy Patterns in Swelling Platelets During Apheresis Platelet Storage

Platelets undergo remarkable morphological changes during storage. Platelets change into different sizes and densities and differ in their biochemistry and functions. However, the correlation between structural heterogeneity and platelet autophagy is largely unknown. The aim of this study was to investigate the autophagy process in vitro, such as routine storage of platelets, and explore the role of reactive oxygen species (ROS) involved in the regulation of platelet autophagy. The ROS and autophagy levels of platelet concentrates from apheresis platelets were evaluated through flow cytometry. The expression levels of autophagy-associated proteins (LC3I, LC3II, Beclin1, Parkin, and PINK1) were measured via Western blot. All biomarkers were dynamically monitored for seven days. Moreover, the morphological characteristics of platelet morphology during storage were analyzed through transmission electron microscopy (TEM). Flow cytometry showed that the levels of total cell ROS and mitochondria ROS increased in the stored platelets. Together with the increase in mitochondrial ROS, the autophagy signal LC3 in the platelets was strongly amplified. The number of swollen platelets (large platelets) considerably increased, and that of autophagy signal LC3 was remarkably higher than that of the normal platelets. Western blot revealed that the expression levels of Beclin1 and LC3 II/LC3 I ratio were enhanced, whereas those of Parkin and PINK1 almost did not change during the seven days of storage. The existence of autophagosomes or autophagolysosomes in the platelets at the middle stage of platelet storage was observed via TEM. Our data demonstrated that the subpopulation of large (swollen) platelets exhibited different autophagy patterns. Furthermore, increased platelet autophagy was associated with mitochondrial ROS. These preliminary results suggest that swelling platelets have a higher autophagy pattern than normal platelets during storage.

Mean platelet volume and neutrophil/lymphocyte ratio in adolescent idiopathic scoliosis: can they be predictive value in diagnosis?

In our study, we evaluated whether mean platelet volume (MPV) and neutrophil lymphocyte ratio (NLR) are predictive values in the diagnosis of Adolescent Idiopathic Scoliosis in patients diagnosed with scoliosis in our clinic. Approximately 15000 patients who applied to our spine outpatient clinic with the suspicion of scoliosis between 2011 and 2018 were reviewed retrospectively. 292 patients were included in the study. The patients were divided into 3 groups. Group 1; control group group 2; group with the possibility of developing scoliosis under follow-upand group 3; the patient group diagnosed with scoliosis. Spinal curvature degrees of the patients were measured using the Cobb method. The MPV and NLR values of the patients were compared with the degree of curvature measured by the cobb method. NLR was 2.17 ± 2.10 K/ul in Group 1, 2.42 ± 1.76 K/ul in Group 2, and 2.72 ± 3.91 K/ul in Group 3. Although the NLR of the 3rd group was higher than the other 2 groups, it was not statistically significant. (p > 0.05). MPV was 7.90 ± 1.07 fL in Group 1, 7.95 ±1.39 fL in Group 2, 8.33 ± 1.37 fL in Group 3.MPV was higher in Group 3 and was found to be statistically significant (p=0.024). After adjusting for the effects of gender and age variables on the groups, the difference in MPV between groups became more significant (p=0.017) . While there was no statistically significant difference between the groups in terms of NLR, it was observed that MPV was statistically significantly higher in patients with AIS.Could this relationship be a promising inflammatory marker for AIS? We think that this question should be answered by studies involving larger patient and control groups.

Laboratory Markers of Platelet Production and Turnover

Platelets are formed from bone marrow megakaryocytes, circulate in blood for 7-10 days, and then are destroyed in the spleen and/or liver. Platelet production depends on the megakaryocyte population state in the bone marrow: number and size of the cells. The platelet turnover, i.e., the number of platelets passing through the bloodstream in a certain time, is determined by both the rate of their production and the rate of their destruction. The review considers laboratory markers, which are used to assess platelet production and turnover in the patients with hematologic and cardiovascular pathologies. These markers include some characteristics of platelets themselves: (i) content of reticulated ("young") forms in the blood detected by their staining with RNA dyes; (ii) indicators of the platelet size determined in hematology analyzers (mean volume, percentage of large forms) and in flow cytometers (light scattering level). Alterations of platelet production and turnover lead to the changes in blood plasma concentrations of such molecules as thrombopoietin (TPO, main mediator of megakaryocyte maturation and platelet formation in the bone marrow) and glycocalicin (soluble fragment of the membrane glycoprotein Ib detached from the surface of platelets during their destruction). Specific changes in the markers of platelet production and turnover have been observed in: (i) hypoproductive thrombocytopenias caused by suppression of megakaryocytes in the bone marrow; (ii) immune thrombocytopenias caused by accelerated clearance of the autoantibody-sensitized platelets; and (iii) thrombocytosis (both primary and reactive). The paper presents the data indicating that in patients with cardiovascular diseases an increased platelet turnover and changes in the corresponding markers (platelet size indexes and content of reticulated forms) are associated with the decreased efficacy of antiplatelet drugs and increased risk of thrombotic events, myocardial infarction, and unstable angina (acute coronary syndrome).

Assessment of the utility of platelet indices to diagnose clinical benign prostatic hyperplasia in dogs

Introduction

Platelet indices changes in severely ill people and in dogs with inflammation are compatible findings. This study aimed to compare platelet indices between dogs with clinical benign prostatic hyperplasia (BPH) and healthy controls. Additionally, to determine whether there is a correlation between the relative prostatic size (S _rel) and the platelet indices in BPH dogs.

Methods

Thirty-five adult intact male dogs of different breeds were allocated to the experimental groups: dogs with clinical BPH (groups A; n = 24; median age of 6 years; the median weight of 8.50 kg) and healthy dogs (group B; n = 11; median age 5.50 years; the median weight of 7.00 kg) based on physical examination, clinical signs, and S _rel detected by ultrasonographic findings. The individual prostatic volume (IPV) was divided by the expected prostatic volume (EPV) to determine the relative prostatic size in dogs over 4 years old. Platelet indices were compared between the two groups, and a correlation between S _rel and these indices was calculated.

Results

The median S _rel of dogs in group A was significantly higher (P = 0.001), and the mean plateletcrit (PCT) was significantly lower (P = 0.003) compared with those in group B. S _rel showed a significant negative correlation with PLT and PCT (r = -0.388; P = 0.02 and r = -0.402; P = 0.01). Receiver operating characteristic (ROC) analysis showed PLT and PCT thresholds for estimating S _rel > 1 with 75% and 87.5% sensitivity and 71.82 and 63.64% specificity.

Discussion

The findings of this study support the use of platelet indices like PLT and PCT to detect clinical BPH in dogs. However, more research is needed to confirm their utility in conjunction with other previously described diagnostic factors.

Role of Reticulated Platelets in Cardiovascular Disease

Human platelets differ considerably with regard to their size, RNA content and thrombogenicity. Reticulated platelets (RPs) are young, hyper-reactive platelets that are newly released from the bone marrow. They are larger and contain more RNA compared to older platelets. In comparison to more mature platelets, they exhibit a significantly higher thrombogenicity and are known to be elevated in patients with an increased platelet turnover such as, diabetics and after acute myocardial infarction. Several studies have shown that RPs correlate with an insufficient antiplatelet response to aspirin and specific P2Y₁₂ receptor inhibitors. In addition, RPs are promising novel biomarkers for the prediction of adverse cardiovascular events in cardiovascular disease. However, the reason for RPs intrinsic hyper-reactivity and their association with ischemic events is not completely understood and the biology of RPs is still under investigation. We here present a structured review of preclinical and clinical findings concerning the role of RPs in cardiovascular disease.

Predictors of Postoperative Pancreatic Fistula (POPF) After Pancreaticoduodenectomy: Clinical Significance of the Mean Platelet Volume (MPV)/Platelet Count Ratio as a New Predictor

PURPOSE

In this study, it was aimed to determine the predictors of clinically relevant postoperative pancreatic fistula (CR-POPF) following pancreaticoduodenectomy (PD) and clinical significance of mean platelet volume (MPV)/total platelet count ratio (MPR) as a new predictor for CR-POPF.

METHODS

A total of 105 patients who underwent PD consecutively due to periampullary located diseases were included in the study. Patients were divided into two groups as CR-POPF and no postoperative pancreatic fistula (No-POPF). Demographic parameters, preoperative serum-based inflammatory indicators, surgical procedures, intraoperative findings, and histopathological parameters were recorded retrospectively from prospectively recorded patient files and compared between the groups.

RESULTS

CR-POPF occurred in 16 (15.2%) patients: 8 (7.6%) were grade B and 8 (7.6%) were grade C according to the ISGPF classification. In univariate analysis, intraoperative blood loss > 580 mL (OR: 5.25, p = 0.001), intraoperative blood transfusion (OR: 5.96, p = 0.002), intraoperative vasoconstrictor medication (OR: 4.17, p = 0.014), benign histopathology (OR: 3.51, p = 0.036), and poor differentiation in malignant tumors (OR: 4.07, p = 0.044) were significantly higher in the CR-POPF group, but not significant in multivariate analysis. Soft pancreatic consistency (OR: 6.08, p = 0.013), pancreatic duct diameter < 2.5 mm (OR: 17.15, p < 0.001), and MPR < 28.9 (OR: 13.91, p < 0.001) were the independent predictors of CR-POPF according to multivariate analysis. Neoadjuvant treatment history and simultaneous vascular resection were less likely to cause CR-POPF development; however, they were insignificant.

CONCLUSION

Soft pancreatic consistency, pancreatic duct diameter, and preoperative MPR were the independent predictors of CR-POPF following PD. Decreased MPR is a strong predictor for CR-POPF and should be considered when deciding treatment strategies.

The predictive value of hematologic parameters in the risk of thyroid malignancy in cases with atypia/follicular lesion of undetermined significance

BACKGROUND

Atypia/follicular lesion of undetermined significance (AUS/FLUS) is still the most challenging category in the Bethesda System for Reporting Thyroid Cytopathology. Therefore, the aim of the current study was to investigate the value of the neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), and mean platelet volume (MPV) in predicting malignancy in cases with AUS/FLUS nodules.

METHODS

A total of 200 patients with AUS/FLUS nodules who underwent thyroidectomy were included in this study. Preoperative hemogram parameters, ultrasonographic findings, fine-needle aspiration results, and postoperative final histopathological diagnoses of the patients were recorded retrospectively.

RESULTS

Thyroid malignancies were detected in 122 of the patients (61.0%). Patients in the benign group (BG) were older than those in the malignancy group (MG) (52.0 ± 11.3 vs. 45.9 ± 12.3 years, p  < 0.001). The median TSH values of the two groups were comparable. Statistically significant differences were obtained between the two groups in respect of mean WBC of 7.53 ± 1.44 in MG and 6.87 ± 1.35 (10³/mm³) in BG, mean neutrophil of 4.65 ± 1.12 in MG and 3.95 ± 0.99 (10³/mm³) in BG, and median NLR of 2.18 (0.71-4.57) in MG and 1.75 (0.80-3.42) in BG (p  < 0.001). The median PLR and MPV values of the two groups were similar. When NLR cut-off point was designated as 2.24, the accuracy of NLR in distinguishing malignancy from the benign condition was 0.65 in ROC analysis (area under the curve, 0.665; specificity, 0.808; sensitivity, 0.492).

CONCLUSION

High NLR values may provide limited help in predicting thyroid malignancy in the AUS/FLUS nodule population, while PLR and MPV are not reliable parameters.

Prognostic Impact of Inflammatory Markers PLR, LMR, PDW, MPV in Medullary Thyroid Carcinoma

BACKGROUND

Neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), lymphocyte-to-monocyte ratio (LMR), mean platelet volume (MPV), and platelet distribution width (PDW) have been used as prognostic biomarkers in various cancers. We aim to investigate the relationship between the above inflammatory indices, clinicopathological features, and postoperative calcitonin (Ctn) progression in medullary thyroid carcinoma (MTC).

METHODS

Sixty-eight patients diagnosed with MTC who underwent surgery at our institution between 2009 and 2020 were retrospectively evaluated. Areas under the receiver operating characteristic curves (ROC) and logistic regression were applied to explore the potential risk factors.

RESULTS

PDW was predictive of lymph node metastasis (LN) (AUC=0.645, P=0.044), PLR, PDW, and MPV were predictive of capsule invasion (AUC=0.771, P=0.045; AUC=0.857, P=0.008; and AUC =0.914, P=0.002, respectively), and MPV and LMR were predictive of postoperative Ctn progression (AUC=0.728, P=0.003; AUC=0.657, P=0.040). Multivariate analysis revealed that PDW ≤ 16.4 [(OR=7.8, 95% CI: 1.532-39.720, P=0.013)] and largest tumor size ≥1 cm (OR=4.833, 95% CI: 1.514-15.427, P=0.008) were potential independent risk factors for lateral LN metastasis. We also found that, MPV ≤ 8.2(OR=13.999, 95% CI: 2.842-68.965, P=0.001), LMR ≤ 4.7 (OR=4.790, 95% CI: 1.034-22.187, P=0.045), and N1 (OR=45.890, 95%CI:3.879-542.936, P=0.002) were potential independent risk factors for postoperative Ctn progression. In addition, compared with the single indicator, the appropriate combination of MPV and LMR could improve the specificity and sensitivity of predicting postoperative Ctn progression.

CONCLUSIONS

PLR, LMR, PDW, and MPV were associated with clinicopathological features and postoperative Ctn progression in MTC, suggesting that those inflammatory indices might be potential biomarkers of MTC.

Prognostic significance of inflammatory markers LMR, PLR, MPV, FIB in intermediate-and high-risk papillary thyroid carcinoma

BACKGROUND

Lymphocyte to monocyte ratio (LMR), platelet to lymphocyte ratio (PLR), mean platelet volume (MPV) and fibrinogen (FIB) have been identified as predictive biomarkers in several malignancies. The aim of this study was to explore the association between inflammatory index with clinicopathologic features as well as recurrence risk in intermediate-to high-risk papillary thyroid carcinoma (PTC).

METHODS

Retrospective evaluation of 212 patients diagnosed with intermediate-to high-risk PTC who underwent surgery at China-Japan Union Hospital between 2015 and 2016. Logistic regression and receiver operating curves (ROC) were used to explore possible risk factors.

RESULTS

LMR was predictive of capsular invasion (AUC=0.595, P=0.017), FIB was predictive of lymph node metastasis (LN) (AUC=0.714, P=0.002), MPV was predictive of largest LN size ≥1cm (AUC=0.639, P=0.002), PLR and MPV were predictive of recurrence (AUC=0.616, P=0.032; AUC=0.626, P=0.020). In addition, FIB ≤ 2.6 (OR=6.440, 95%CI:1.777-23.336, P=0.005) and capsular invasion (OR=3.773, 95%CI:1.171-12.159, P=0.026) were identified as independent risk factors for lymph node metastasis by multivariate analysis. In addition, LN metastasis (P=0.048), largest LN size ≥ 1 cm (P=0.032), MPV > 9.4 (P=0.046), and PLR ≤ 128.1 (P=0.032) were significantly related with recurrence. Further multivariate regression analysis revealed that PLR ≤ 128.1 was a potentially independent risk factor for recurrence. Specifically, the risk of recurrence was 2.951 times higher in patients with a PLR ≤ 128.1 compared with patients with a PLR > 128.1 (OR=2.951, 95% CI:1.238-7.037, P=0.015).

CONCLUSION

In intermediate-to high-risk PTC, LMR, PLR, MPV, and FIB could predict clinicopathologic features and recurrence, with lower PLR being the potential risk factors for recurrence.

Platelet Distribution Width Is Associated with P-Selectin Dependent Platelet Function: Results from the Moli-Family Cohort Study

Defined as an index of platelet size heterogeneity, the platelet distribution width (PDW) is still a poorly characterized marker of platelet function in (sub)clinical disease. We presently validated PDW as a marker of P-selectin dependent platelet activation in the Moli-family cohort. Platelet-bound P-selectin and platelet/leukocyte mixed aggregates were measured by flow cytometry in freshly collected venous blood, both before and after in vitro platelet activation, and coagulation time was assessed in unstimulated and LPS- or TNFα-stimulated whole blood. Closure Times (CT) were measured in a Platelet Function Analyzer (PFA)-100. Multivariable linear mixed effect regression models (with age, sex and platelet count as fixed and family structure as random effect) revealed PDW to be negatively associated with platelet P-selectin, platelet/leukocyte aggregates and von Willebrand factor (VWF), and positively with PFA-100 CT, and LPS- and TNF-α-stimulated coagulation times. With the exception of VWF, all relationships were sex-independent. In contrast, no association was found between mean platelet volume (MPV) and these variables. PDW seems a simple, useful marker of ex vivo and in vitro P-selectin dependent platelet activation. Investigations of larger cohorts will define the usefulness of PDW as a risk predictor of thrombo-inflammatory conditions where activated platelets play a contributing role.

The Role of Hematological Inflammatory Biomarkers in the Diagnosis of Lung Cancer and in Predicting TNM Stage

OBJECTIVE

The aim of study is to investigate whether hematological inflammatory biomarkers could be useful to detect patients with lung cancer.

METHODS

The contribution of hematological biomarkers to the diagnosis of lung cancer and prediction of TNM was examined.

RESULTS

NLR, PLR, MPV values were found to be higher in patients with lung cancer (all p < .001). NLR and PLR were found to be high, MPV was found to be lower in disease of advanced stage (p < .001).

CONCLUSIONS

This study found that NLR, PLR and MPV values were significantly higher in patients with lung cancer.

Mean Platelet Volume/Platelet Count Ratio and Risk of Progression in Glioblastoma

Objective

The mean platelet volume/platelet count (MPV/PC) ratio is an emerging biomarker in selected types of cancer. The objective of this study is to analyze the association of MPV/PC ratio with progression and survival in glioblastoma (GB) patients, with consideration of patient demographics, tumor morphology, extent of resection, molecular pathology, and oncological therapy.

Methods

One hundred ninety-one patients with newly diagnosed GB were analyzed retrospectively. MPV/PC ratio groups (≤ or >0.0575) were dichotomized into low-MPV/PC ratio (≤0.0575) and high-MPV/PC ratio (>0.0575) groups according to the most significant split in the log-rank test.

Results

A two-sided Fisher's exact test showed no significant differences in the confounders between the low- and high-MPV/PC ratio groups. The median progression-free survival (PFS) was 9.0 months (95% CI=8.0-10.0) in the low-MPV/PC ratio group (n=164) and 6.0 months (95% CI=3.0-8.9) in the high-MPV/PC group (n=28) (p=0.013). Multivariate Cox regression analysis including the O-6-methylguanine-DNA methyltransferase (MGMT) status, age (≤/>65 years), baseline Karnofsky Performance Status (KPS), and MPV/PC ratio showed high-MPV/PC ratio as a predictor of progression (p =0.04, HR=1.61, 95% CI=1.01-2.57). In the subgroup of IDH1 wild-type GBs, high MPV/PC ratio was still a significant predictor for shortened PFS (p=0.042, HR=1.60, 95% CI=1.02-2.52). MPV/PC ratio showed no significant effect in the overall survival (OS) analysis. Median OS was 15.0 months in the high-MPV/PC ratio group and 21.0 months in the low-MPV/PC ratio group (p=0.22).

Conclusion

MPV/PC ratio may independently predict the progression-free survival rates of patients with glioblastoma multiforme.

Platelet adhesion in type 2 diabetes: impact of plasma albumin and mean platelet volume

Background

Altered mean platelet volume (MPV) and plasma albumin has been reported in type 2 diabetes (T2D). MPV is suggested to predict cardiovascular risk but there is a lack of evidence for associations between MPV and platelet adhesion. Plasma albumin and magnesium are other factors reported to influence thrombotic risk. The objectives of this study were to assess the association between platelet adhesion and plasma factors with a potential role to affect platelet activation.

Methods

Blood was collected from 60 T2D patients and 60 healthy controls. Platelet adhesion to different protein surfaces induced by various soluble activators were measured in microplates. MPV, albumin and magnesium were analysed together with additional routine tests.

Results

Despite normal levels, plasma albumin significantly correlated with adhesion of T2D platelets but not with controls. There was a significant association between MPV and platelet adhesion in both groups, but association was smaller in T2D. Levels of glucose, HbA1c or magnesium did not correlate with platelet adhesion.

Conclusions

Plasma albumin was associated with platelet adhesion in T2D suggesting that albumin may be a factor to consider upon cardiovascular risk assessment. MPV was more associated with the level of platelet adhesion in healthy individuals than in well-controlled T2D patients.

Platelet reticulated forms, size indexes, and functional activity. Interactions in healthy volunteers

Reticulated platelets (RP) are young, functionally active platelet forms which are detected by RNA staining. Their content in the circulation reflects the intensity of bone marrow thrombocytopoesis. The aim of this study was to assess in healthy volunteers the relationship between RP percentage and platelet size and activity. RP were quantitated by thiazole orange staining using flow cytometry. Platelet size indexes included mean platelet volume (MPV), platelet large cell ratio (P-LCR) measured in a Coulter type hematological analyzer and forward scattering (FSC) measured in a flow cytometer. Platelet functional activity was evaluated by expression of activated glycoprotein (GP) IIb-IIIa (PAC-1 antibody binding) and P-selectin with the use of flow cytometry. Platelets were activated by thrombin receptor activating peptide (TRAP) (10 and 1 µM) and ADP (20 and 2.5 µM). The percentage of RP in healthy volunteers varied from 2.9% to 23.8% (mean ± SD ‒ 11.7 ± 4.7%, n = 99) and correlated with all platelet size indexes: MPV, P-LCR and FCS (r from 0.452 to 0.529, p < .001, n = 87-99). On average, RP were distributed at a ratio of 9:1 between 50% subpopulations of large and small platelets according to their FSC index. Expression of GP IIb-IIIa activated form correlated with RP percentage and platelet size indexes when platelets were activated by TRAP and ADP at both applied concentrations (r from 0.309 to 0.560, p from 0.014 to < 0.001, n = 50-62). P-selectin expression correlated with RP percentage and platelet size indexes when platelets were activated by 10 µM TRAP inducing maximum expression of this activation marker (r from 0.332 to 0.556, p from 0.008 to < 0.001, n = 65), but not by weaker agonists: 1 µM TRAP, 20 and 2.5 µM ADP (r < 0.3, n = 54-66). Thus, high RP content in healthy volunteers is associated with increased platelet size and activity in the whole platelet population.

Platelets as messengers of early-stage cancer

Platelets have an important role in tumor angiogenesis, growth, and metastasis. The reciprocal interaction between cancer and platelets results in changes of several platelet characteristics. It is becoming clear that analysis of these platelet features could offer a new strategy in the search for biomarkers of cancer. Here, we review the human studies in which platelet characteristics (e.g., count, volume, protein, and mRNA content) are investigated in early-stage cancer. The main focus of this paper is to evaluate which platelet features are suitable for the development of a blood test that could detect cancer in its early stages.

The Role of Inflammatory Hematological Markers in Predicting IVF Success

Objective:

To investigate the predictive role of inflammatory hematological markers on treatment success in in vitro fertilization (IVF) patients.

Methods:

In this study, we analyzed the data from the patients who admitted to our IVF center, and we recorded demographic characteristics, medical histories, laboratory biomarkers, cycle characteristics, and IVF outcomes from the patients’ files. We assessed the value of white blood cell (WBC) counts, neutrophil/lymphocyte ratio (NLR), monocyte/lymphocyte ratio (MLR), platelet/lymphocyte (PLR), mean platelet volume (MPV) and platelet distribution width (PDW) of the patients from their complete blood count. We compared these values in terms of predicting positive HCG test after embryo transfer (ET).

Results:

There were 132 patients, of which 63 (47.7%) were treated for male factor, 43 (32.6%) for unexplained infertility, 19 (14.4%) for diminished ovarian reserve, 5 (3.8%) for endometriosis and 2 (1.5%) for hypogonadotropic hypogonadism. After ovarian stimulation and oocyte retrieval, 115 patients underwent embryo transfer, and 28 patients had a positive HCG test (24.3%). The positive HCG group had a statistically lower PLR when compared to the HCG (-) group (p=0.02). In the ROC analysis, PLR was significant in predicting positive HCG (p=0.028). However, when we added other factors to the model, only age and MII oocyte count were successful in predicting pregnancy outcomes in a logistic regression analysis.

Conclusion:

According our results, inflammatory hematological markers were not effective in predicting IVF success.

Mean Platelet Volume as a Marker of Vasculogenic Erectile Dysfunction and Future Cardiovascular Risk

Cardiovascular diseases are the main cause of mortality in the Western population, so the attempt to find a marker capable of predicting their early onset is not surprising. It is known that arteriogenic erectile dysfunction (ED) precedes the onset of a major coronary event by several years. However, a marker that is able to early identify those patients who should undergo further diagnostic investigations is, to date, missing. Recent research on this topic has focused on the role of the mean platelet volume (MPV), a marker of platelet activity that is high in most vascular diseases, such as coronary artery disease (CAD), stroke, peripheral artery disease (PAD), and ED. The basic pathophysiological mechanism of all these clinical conditions is atherosclerosis. Platelets play a central role in amplifying this process both indirectly by stimulating endothelial cells to produce inflammatory cytokines and chemokines, and directly through the expression of membrane receptors and the release of molecules that contribute to the formation of atherosclerotic plaque. The objective of this review is to critically analyze the evidence on the role of MPV in predicting the diagnosis and severity of vasculogenic ED and the possibility of using this simple marker as a first step to start a diagnostic process aimed at assessing the cardiovascular risk in these patients.

Coagulopathy signature precedes and predicts severity of end-organ heat stroke pathology in a mouse model

BACKGROUND

Immune challenge is known to increase heat stroke risk, although the mechanism of this increased risk is unclear.

OBJECTIVES

We sought to understand the effect of immune challenge on heat stroke pathology.

PATIENTS/METHODS

Using a mouse model of classic heat stroke, we examined the impact of prior viral or bacterial infection on hematological aspects of recovery. Mice were exposed to heat either 48 or 72 hours following polyinosinic:polycytidylic acid (poly I:C) or lipopolysaccharide injection, time points when symptoms of illness (fever, lethargy, anorexia) were minimized or completely absent.

RESULTS

Employing multivariate supervised machine learning to identify patterns of molecular and cellular markers associated with heat stroke, we found that prior viral infection simulated with poly I:C injection resulted in heat stroke presenting with high levels of factors indicating coagulopathy. Despite a decreased number of platelets in the blood, platelets are large and non-uniform in size, suggesting younger, more active platelets. Levels of D-dimer and soluble thrombomodulin were increased in more severe heat stroke, and in cases of the highest level of organ damage markers D-dimer levels dropped, indicating potential fibrinolysis-resistant thrombosis. Genes corresponding to immune response, coagulation, hypoxia, and vessel repair were up-regulated in kidneys of heat-challenged animals; these correlated with both viral treatment and distal organ damage while appearing before discernible tissue damage to the kidney itself.

CONCLUSIONS

Heat stroke-induced coagulopathy may be a driving mechanistic force in heat stroke pathology, especially when exacerbated by prior infection. Coagulation markers may serve as accessible biomarkers for heat stroke severity and therapeutic strategies.

Large and small platelets-(When) do they differ?

Platelets are most important in providing cellular hemostasis but also take part in inflammation and immune processes. Increased platelet size has been regarded as a feature describing a young and more reactive subpopulation until studies were published which questioned this concept. Moreover, changes of platelet size given by the mean platelet volume (MPV) were described for immune thrombocytopenia, cardiovascular disease, atherosclerosis, venous thromboembolism, chronic lung disease, sepsis, cancer-associated thrombosis, autoimmune disorders, and others. This review summarizes the literature on what is known about platelets with different size and describes controversies of studies with large and small platelets putting a focus on their thrombogenicity, age, and on the association of MPV with the mentioned diseases.

Fractional carbon dioxide laser combined with intradermal injection of autologous platelet-rich plasma versus noncross-linked hyaluronic acid in the treatment of atrophic postacne scars: A split face study

BACKGROUND

Atrophic acne scarring is a common cosmetic problem that may affect 95% of patients with acne.

AIMS

The objective is to evaluate the efficacy of the fractional CO₂ laser combined with intradermal injection of PRP versus intradermal injection of noncross-linked hyaluronic acid in the treatment of different types of atrophic postacne scars.

METHODS

The study included 30 patients with postacne scars. All the patients received 3 treatments of fractional CO₂ laser combined with intradermal injection of PRP at one side of the face compared with intradermal injection of noncross-linked hyaluronic acid at the other side of the face. Efficacy of the treatment was assessed by the physician's clinical assessment using Goodman and Baron's qualitative and quantitative grading systems and histopathological evaluation from six participants.

RESULTS

The study included 30 patients ages ranging from 25 to 44 years old. There was a statistically significant reduction in the severity of acne scars on both sides after treatment using qualitative and quantitative Goodman and Baron. Histopathological evaluation showed an increase in the collagen and elastic fiber content in both modalities with a more favorable outcome in the PRP-treated side.

CONCLUSION

Both treatment modalities resulted in a significant clinical and histopathological improvement in atrophic postacne scar with insignificant difference between them.

Influence of diagnosis of venous thromboembolism on immature platelets, absolute platelet count and platelet aggregation over time

The extent of the involvement of platelets in venous thromboembolisms (VTE) is still not fully understood. Immature platelets are large, RNA-rich, prothrombotic platelets. They are involved in arterial thromboembolisms and are associated with adverse cardiovascular events. Their role in VTE has not been investigated before. The aim of this study was to assess different platelet parameters including immature platelet fraction (IPF), immature platelet count (IPC), absolute platelet count and platelet aggregation (PA) over time in patients with VTE at time of diagnosis, as well as at 3-10 days and at 90-110 days after diagnosis. 50 healthy volunteers similar in age and sex to patients served as controls at diagnosis. IPF was measured by the Sysmex XE-5000 analyzer, PA was assessed using the Multiplate analyzer. Diagnosis of VTE had no relevant effect on IPF and IPC whereas absolute platelet count and PA were significantly decreased compared to controls. In the course of VTE, IPF decreased significantly, whereas IPC, absolute platelet count and PA increased. In conclusion, VTE was associated with relevant changes of the absolute platelet count and PA at diagnosis, as well as changes in IPF and IPC over time reflecting a relevant and measurable platelet consumption in VTEs.

Predictive and prognostic values of preoperative platelet parameters in patients with gynecological tumors

Background

Platelets play a role in tumor cell growth, metastasis, and angiogenesis, and the present study aimed to evaluate diagnostic and prognostic values of platelet parameters in patients with gynecological tumors.

Methods

A total of 1062 women were included. Differences of platelet parameters (platelet count [PLT], plateletcrit [PCT], mean platelet volume [MPV], platelet‐large cell rate [P‐LCR], and platelet distribution width [PDW]) between different categories were analyzed by nonparametric test. The optimal cutoff value was calculated with receiver operating characteristic analysis. Overall survivals were analyzed with Kaplan‐Meier method and log‐rank tests for univariate analysis.

Results

Platelet count and PCT were significantly increased, and MPV and P‐LCR were significantly reduced in malign and benign gynecological tumor groups compared with the controls (P < .001); PDW had no significant differences. There were no significant differences in PLT, PCT, MPV, P‐LCR, and PDW between different tumor locations and pathologic types. The optimal cutoff values of PLT, PCT, MPV and P‐LCR were 274, 0.26, 10.08, and 24.8 (AUC: 0.661, 0.643, 0.593, 0.562), and PCT had preferable sensibility and specificity (50.84% and 70.42%) in predicting the presence of gynecological tumors. According to survival analysis, increased PLT (≥274 × 10⁹/L) and PCT (≥0.26), and induced MPV (<10.08 fL) and P‐LCR (<24.8%) were associated with shorter overall survival.

Conclusions

Platelet count, PCT, MPV, and P‐LCR can be used as preferable auxiliary parameters for predicting the presence of gynecological tumors. Increased PLT and PCT, or decreased MPV and P‐LCR indicated a heavier tumor burden and shorter overall survival.

Reticulated platelets and immature platelet fraction: Clinical applications and method limitations

So-called "reticulated" or "immature platelets," which are newly released into the circulation, are more reactive than mature platelets, contain more RNA, and can be counted using flow cytometry after staining with thiazole orange or using some fully automated hematology analyzers, albeit with numerical disagreement. This review provides an overview of the state of the art of available technology for measuring immature or reticulated platelets (RP) with preanalytical (time stability, biological variation), analytical (methods, imprecision), and postanalytical (reference range) limitations. We also analyzed the clinical conditions in which immature/RP can be considered a diagnostic or prognostic tool (ie, differential diagnosis of thrombocytopenia, recovery after bone marrow or stem cell transplantation, risk assessment in cardiovascular diseases, response to antiplatelet drugs). They might also be of clinical utility in other settings but with lower evidence. The lack of a specific reference method and universal control material, as well as dependency of results on the measurement technique used, calls for different reference intervals and compromises comparison between clinical studies carried out using different analytical methods. To obviate lack of agreement between methods, more specific RNA dyes are necessary and the impact of the platelet size on the fluorescence signal defined. In the harmonization age, also in nomenclature field, a new definition instead of "reticulated" or "immature" platelets would be useful, and "young platelets" might be a more appropriate definition taking into account both the age and the functionality of this platelet fraction.

Activation-induced changes in platelet surface receptor expression and the contribution of the large-platelet subpopulation to activation

OBJECTIVE

Platelet surface receptors are also present subcellularly in organelle membranes and can be expressed on the surface upon platelet activation. However, some receptors were reported to be decreased after activation. We analyzed the mechanism of activation-dependent expression for different receptors.

METHODS

Flow cytometry using platelet-rich plasma or washed platelets was used to analyze receptor-expression changes after platelet activation by glycoprotein (GP) VI-specific agonists, crosslinked collagen-related peptide (CRP-XL) and convulxin (Cvx), and thrombin. Platelets prelabeled with fluorescent antibody specific for a receptor were allowed to adhere on immobilized collagen or fibrinogen and post-stained with antibody against the same receptor labeled with another fluorophore, allowing us to differentiate preexisting receptors from newly expressed receptors.

RESULTS

Surface expression of αIIbβ3 increased in CRP-XL-, Cvx-, or thrombin-stimulated platelets, but GPIb decreased due to shedding and internalization. Both total and dimeric GPVI increased in thrombin-induced platelets, but decreased in platelets stimulated by Cvx, as a result of internalization. The larger platelets showed a greater increase in surface receptor (α2β1, αIIbβ3, GPVI, GPIb) expression upon activation compared to the smaller ones. Pre- and postlabeling with antibody specific for the same receptor, but conjugated with different fluorophores, allowed us to differentiate the receptors expressed on the surface of resting platelets from receptors newly exposed to the surface upon platelet activation.

CONCLUSIONS

Increased receptor expressions after activation are mainly manifested in the larger platelets. On platelets adhered on fibrinogen, the newly expressed receptors, especially GPVI, are localized in the lamellipodia of the spread platelets.

Advances in Platelet Subpopulation Research

Although lacking a nucleus, platelets are increasingly recognized not only for their complexity, but also for their diversity. Some 50 years ago platelet subpopulations were characterized by size and density, and these characteristics were thought to reflect platelet aging. Since, our knowledge of platelet heterogeneity has grown to recognize that differences in platelet biochemistry and function exist. This includes the identification of vanguard and follower platelets, platelets with differing procoagulant ability including "COAT-platelets" which enhance procoagulant protein retention on their surface, and most recently, the identification of platelet subpopulations with a differential ability to generate and respond to nitric oxide. Hence, in this mini-review, we summarize the current knowledge of platelet subpopulation diversity focusing on their physical, biochemical, and functional heterogeneity. In addition, we review how platelet subpopulations may change between health and disease and how differences among platelets may influence response to anti-platelet therapy. Finally, we look forward and discuss some of the future directions and challenges for this growing field of platelet research.

Nailfold capillary morphology and platelet function in patients with exfoliative glaucoma

Purpose

The purpose of the present study was to evaluate the nailfold capillary morphological features in patients with exfoliative glaucoma (XFG) and compare them with those pertaining to primary open-angle glaucoma (POAG), normal controls and subjects with exfoliation syndrome (XFS). The second purpose was to investigate all parameters related to platelet function on the hemogram, including the platelet count (PLT), the mean platelet volume (MPV), platelet distribution width (PDW), and plateletcrit (PCT) in patients with XFG. These parameters were subsequently compared with those belonging to normal controls, POAG and XFS subjects.

Methods

This case control study involved 152 consecutive patients that were examined at the Glaucoma Department of Clinic for Eye Diseases, Clinical Centre of Serbia, as the referral center for glaucoma in Serbia, between June 2016 and December 2017.

Results

Regarding capillaroscopic characteristics, statistically significant difference was found in capillary diameter and tortuosity between the XFG and POAG group (p = 0.050 and p = 0.035) and the XFG and NC group (p = 0.003 and p = 0.044), as well as in the distribution of capillary loops and avascular zones between the XFG and NC group (p = 0.014 and p = 0.004). The subjects with XFG had lower PLT values compared to POAG patients (p = 0.022).

Conclusions

In conclusion, to the best of our knowledge, this study marks the first attempt to evaluate capillary morphology as well as to investigate all parameters related to platelet function on the hemogram, in patients with newly diagnosed XFG. Our findings revealed nailfold capillary morphological vascular changes in XFG patients. The subjects with XFG had lower PLT values and a higher MPV serum parameter compared to normal controls and patients with POAG. Further research in this field should therefore aim to evaluate the consequences of the aforementioned microvascular abnormalities in patients with XFG.

Platelet mass index and prediction of severity of transient tachypnea of the newborn

BACKGROUND

Platelet mass index (PMI) is associated with platelet functionality. The aim of this study was to evaluate the role of PMI in predicting the severity of transient tachypnea of the newborn (TTN).

METHODS

Infants with gestational age ≥37 weeks and birthweight ≥2,000 g who were given nasal intermittent mandatory ventilation for TTN ≤6 h after birth were retrospectively enrolled in this study. PMI was calculated using the following formula: PMI = platelet count × mean platelet volume/10³ (fL/nL). The study infants (n = 101) were divided into two groups according to the duration of tachypnea: ≤48 h (n = 45) and >48 h (n = 56).

RESULTS

The PMI and platelet count were significantly lower in the group with tachypnea duration >48 h than in the tachypnea duration ≤48 h group (P < 0.001 and P = 0.04, respectively). A negative significant correlation was noted between PMI and the duration of tachypnea (r = -0.43, P < 0.001). A PMI cut-off of 1,562 fL/nL can predict prolonged tachypnea (>48 h) with a sensitivity of 62.5%, specificity of 68.9%, positive predictive value of 71.4%, and negative predictive value of 59.6% (area under the curve, 0.682 ± 0.053; P = 0.002).

CONCLUSIONS

Lower PMI and lower platelet count are associated with longer duration of tachypnea in patients with TTN.

Comparison of Mean Platelet Volume, Platelet Count, Neutrophil/ Lymphocyte Ratio and Platelet/Lymphocyte Ratio in the Euthyroid, Overt Hypothyroid and Subclinical Hyperthyroid Phases of Papillary Thyroid Carcinoma

INTRODUCTION

Thyroid hormones are essential for the normal development, differentiation, metabolic balance and physiological function of all tissues. Mean platelet volume (MPV) indicates mean platelet size and reflects platelet production rate and stimulation. Increased platelet size has been observed in association with known cardiovascular risk factors. The neutrophil/lymphocyte ratio (NLR) and platelet/lymphocyte ratio (PLR) are known markers of the systemic inflammatory response. This study aimed to investigate the effect of thyroid hormone changes by comparing platelet count, MPV values, NLR and PLR in thyroid papillary carcinoma.

METHODS

Forty-nine females and nine males comprising a total of 58 patients were included in the study. Clinical and laboratory parameters of patients were recorded in the following three phases of the disease: euthyroid phase (before thyroid surgery), overt hypothyroid (OH) phase (before radioactive iodine [RAI] treatment) and subclinical hyperthyroid (SCH) phase (six months after RAI treatment).

RESULTS

The mean thyroid-stimulating hormone (TSH) values of the patients in the euthyroid, OH and SCH phases were 1.62±1.17, 76.4±37.5 and 0.09±0.07 µIU/mL, respectively. The mean MPV values of the patients in the euthyroid, OH and SCH phases were 9.45±1.33, 9.81±1.35 and 9.96±1.21 fL, respectively. MPV was significantly higher in the SCH phase than in the euthyroid phase (p=0.013). Platelet count, NLR and PLR were not statistically different between the euthyroid, OH and SCH phases.

CONCLUSION

The results of this study demonstrated that the levels of MPV increased significantly in the SCH phase in patients with papillary thyroid carcinoma (PTC), and increased MPV values contributed to increased risk of cardiovascular complications. These findings suggest that MPV can be a valuable, practical parameter for monitoring the haemostatic condition in thyroid disorders. No significant difference was observed in platelet count, NLR and PLR in all stages of PTC.

Low-level light therapy reduces platelet destruction during extracorporeal circulation

Extracorporeal circulation causes many deleterious effects on blood cells. Low-level light therapy (LLLT) in the red/near-infrared spectral range is known for its cytoprotective properties but its use during cardiopulmonary bypass (CPB) has not yet been studied. We aimed to assess whether LLLT protects platelets during CPB. 24 pigs were connected to 1-hour-CPB and observed for the next 23 hours. In 12 animals, blood circulating through the oxygenator was treated with LLLT. Platelet count and function were monitored throughout the experiment. The decrease in platelet count was greater in the control group, especially during CPB and after 24 hours. In LLLT group CD62P expression remained quite stable up to the 12^th hour of the experiment, whereas in the control group it continuously decreased till the end of observation. Platelets in the control group were more prone to aggregation in the postoperative period than at the beginning of the experiment, whereas platelets in the LLLT group aggregated similarly or less intense. Limitation of platelet loss, pattern of aggregation and CD62P expression suggest that LLLT may stabilize platelet function during CPB and diminish the negative effects associated with the interaction of cells with an artificial surface.

Is Monitoring Mean Platelet Volume Necessary in Breast Cancer Patients?

Background

Mean platelet volume (MPV) is a parameter that increases during thrombotic and cardiovascular events. Tamoxifen (Tmx) and aromatase inhibitors (AIs), which are adjuvant endocrine therapies, may cause serious side effects, such as vascular thrombosis. The present study investigated the changes in MPV values of breast cancer patients receiving long-term adjuvant hormone therapy and the relationship of MPV with adverse effects of hormonotherapy.

Methods

Data of 261 patients who had pathologically confirmed estrogen or progesterone receptor positive invasive breast cancer and had received hormonotherapy for at least a 5-year period were retrospectively analyzed. MPV levels were measured at baseline and at the first and fifth year of hormone therapy.

Results

All patients were females and their median age was 50 years (range, 27–78 years). The mean MPV value was significantly increased in all patients in the Tmx, AI, and switch groups over time (p<0.001).

Conclusion

This is the first study evaluating the relationship between the 5-year adjuvant endocrine therapy and changes in MPV values in breast cancer patients. Monitoring changes in MPV values may be predictive for severe side effects in breast cancer patients receiving hormone therapy.

Multirefractory primary immune thrombocytopenia; targeting the decreased sialic acid content

Patients with multirefractory immune thrombocytopenia (ITP) have limited treatment options. Recent data suggest that specific anti-platelet antibodies may cause destruction of platelets by favoring platelet loss of sialic acid. In this multicenter study 35 patients with ITP, including 16 with multirefractory disease, were analyzed for antiplatelet-antibodies, thrombopoietin (TPO) levels, and platelet desialylation. In selected cases, responses to a novel treatment strategy using oseltamivir were tested. We found that antibodies against GPIbα were overrepresented in multirefractory patients compared to responders (n = 19). In contrast to conventional ITP patients, multirefractory patients exhibited a significant increased platelet activation state (granule secretion) and desialylation (RCA-1 binding) (p < 0.05), and a trend toward higher plasma TPO concentrations. The decreased sialic acid content seemed to be restricted to platelet glycoproteins, since other plasma proteins were not hypoglycosylated. A total of 10 patients with multirefractory ITP having remarkable loss of platelet terminal sialic acids were given oseltamivir phosphate. When the antiviral drug was combined with TPO receptor agonists (TPO-RAs) or with immunosuppressant drugs, platelet responses were observed in 66.7% of patients. All responding patients presented with antibodies reactive only against GPIbα. These findings suggest that desialylation may play a key pathogenic role in some multirefractory ITP patients, and provide diagnostic tools for the identification of such patients. Furthermore, we show that sialidase inhibitor treatment in combination with therapies that help to increase platelet production can induce sustained platelet responses in some patients with anti-GPIbα -mediated thrombocytopenia that have failed previous therapies.

A characteristic flow cytometric pattern with broad forward scatter and narrowed side scatter helps diagnose immune thrombocytopenia (ITP)

Various disorders cause severe thrombocytopenia, which can lead to critical hemorrhage. Procedures that rapidly support the diagnosis and risk factors for serious bleeding were explored, with a focus on immune thrombocytopenia (ITP). Twenty-five patients with thrombocytopenia, including 13 with newly diagnosed ITP, 3 with chronic ITP, 6 with aplastic anemia (AA), and 3 with other thrombocytopenia (one acute myeloid leukemia, one acute lymphoblastic leukemia, and one hemophagocytic lymphohistiocytosis), were reviewed. In addition to platelet-related parameters obtained by an automated hematology analyzer, flow cytometric analysis of platelets was performed. A characteristic flow cytometric pattern with broad forward scatter and narrowed side scatter, which is specific to ITP, but not other types of thrombocytopenia, was found. CD62P-positive platelets were increased in newly diagnosed ITP cases compared to control (P < 0.0001), AA (P = 0.0032). Moreover, detection of dramatic changes in these parameters on sequential monitoring may suggest internal hemorrhage, even absent skin or visible mucosal bleeding. The bleeding score for visible mucosae had a negative correlation with platelet count and a positive correlation with immature platelet fraction (%), forward scatter, and CD62P. This characteristic flow cytometric pattern makes it possible to distinguish ITP from other thrombocytopenic disorders.

Toward the Relevance of Platelet Subpopulations for Transfusion Medicine

Circulating platelets consist of subpopulations with different age, maturation state and size. In this review, we address the association between platelet size and platelet function and summarize the current knowledge on platelet subpopulations including reticulated platelets, procoagulant platelets and platelets exposing signals to mediate their clearance. Thereby, we emphasize the impact of platelet turnover as an important condition for platelet production in vivo. Understanding of the features that characterize platelet subpopulations is very relevant for the methods of platelet concentrate production, which may enrich or deplete particular platelet subpopulations. Moreover, the concept of platelet size being associated with platelet function may be attractive for transfusion medicine as it holds the perspective to separate platelet subpopulations with specific functional capabilities.

Influence of platelet count, platelet mass index, and platelet function on the spontaneous closure of ductus arteriosus in the prematurity

BACKGROUND

This study aims at evaluating the influence of platelet count, platelet mass index, and platelet function on the spontaneous closure of ductus arteriosus in prematurity.

METHODS

All preterm babies were divided into two groups, including Group 1 with "open PDA" and Group 2 with "closed PDA". The variables of platelet count, mean platelet volume, platelet mass index, and platelet function were analyzed and compared between two groups of patients to identify the factors that significantly influenced spontaneous closure of ductus arteriosus.

RESULTS

Twenty-four patients were in the "open PDA" group, whereas 36 patients were in the "closed PDA" group. Mean GA and BW were 27.6 ± 1.8 (23.1-30.4) and 28 ± 1.6 (23.4-30.6) weeks and 1009 ± 270 (585-1480) g and 1035 ± 298 (505-1500) g in "open PDA" and "closed PDA" groups, respectively (p > 0.05). The incidence of "Collagen-ADP > 130 s" was significantly higher in the "open PDA" group, and the levels of hemoglobin and hematocrit were significantly lower in the "open PDA" group (p < 0.05). Multivariate logistic regression analysis showed that respiratory distress syndrome (OR: 9, CI: 1.5-51.8) and collagen-ADP > 130 s (OR: 5.7 CI: 1.55-21.3) are two independent factors associated with ductal patency.

CONCLUSION

This is the first study in the English literature providing evidence of the influence of platelet dysfunction on the spontaneous closure of ductus arteriosus in prematurity. Longer collagen-ADP duration is identified as a risk factor of ductal closure.

Are there any variation in neutrophil lymphocyte ratio, mean platelet volume and platelet count between papillary thyroid cancer and benign nodular thyroid diseases

Objective: Neutrophil lymphocyte ratio (N/L) and mean platelet (Plt) volume (MPV), the markers of systemic inflammatory response, has been investigated in many cancers, but data for the head and neck cancers and thyroid carcinoma are limited. It had been purposed to study N/L, MPV, and Plt levels in papillary thyroid carcinoma (PTC) as a diagnostic marker. Material and Methods: A total of 104 patients, had undergone ultrasonography guided fine needle aspiration (FNA) and thyroidectomy, for the indicated cases, between April 2010 and August 2013, were enrolled in the study. The laboratory tests, regarding N/L, MPV, and Plt, of the cases had been collected retrospectively. Results: No difference was found between PTC and benign nodular thyroid diseases (BNTD) in terms of age, gender, size of the nodule, N/L, MPV, and Plt (p > 0.05). Conclusion: The preoperative inflammatory hematological parameters, in terms of N/L, MPV, and Plt, may not be useful as a predictive diagnostic marker of the thyroid malignancy, PTC.

Utility of complete blood count parameters to detect premature ovarian insufficiency in cases with oligomenorrhea/amenorrhea

BACKGROUND

There are very few biomarkers available to diagnose cases with premature ovarian failure. Some complete blood count parameters have been introduced to be diagnostic biomarkers for several disorders associated with inflammatory process. Due to the evidence that indicated chronic inflammatory process to be underlying pathophysiology in premature ovarian insufficiency (POI), we aimed to assess the predictive value of complete blood count parameters for POI diagnosis.

METHOD

A total of 96 women diagnosed to have premature ovarian failure were compared with 110 otherwise healthy women in terms of some basal hormone levels and complete blood count parameters.

RESULTS

Mean age was similar between groups. Neutrophil/lymphocyte and mean platelet volume/lymphocyte ratios were significantly higher in group with POI (P < .001, P < .003, respectively). In group with POI, there were significant correlations between anti-Mullerian hormone and follicle stimulating hormone (r = -.30, P <.05), anti-Mullerian hormone and white blood cell count (r = .23, P < .05). Mean platelet volume/lymphocyte ratio significantly predicted cases with POI (AUC = 0.607, %95 CI: 0.529-0.684; P < .001).

CONCLUSIONS

Neutrophil/lymphocyte and mean platelet volume/lymphocyte ratios are elevated in POI. There have been some controversies about the value of neutrophil/lymphocyte in POI diagnosis. We suggest mean platelet volume/lymphocyte ratio as a new biomarker in early POI because it is cheap and easily accessible compared to anti-Mullerian hormone.

Immature platelets as a novel biomarker for adverse cardiovascular events in patients after non-cardiac surgery

This study evaluates whether immature platelets (IPF) determined in the post anesthesia care unit (PACU) can predict major adverse cardiovascular events (MACE) or other thromboembolic events after intermediate and high-risk surgery. IPF are increased in patients with acute coronary syndrome and recently gained interest as novel biomarker for risk stratification. In this prospective observational trial 732 patients undergoing intermediate or high-risk non-cardiac surgery were enrolled (NCT02097602). IPF was measured preoperatively and postoperatively in the PACU. Primary outcome was a composite endpoint defined as MACE, deep vein thrombosis or pulmonary embolism during hospital stay (modMACE). A cut off for IPF identifying a threshold between a low and high risk for modMACE was calculated by logrank optimization. A multivariate Cox regression was calculated in a forward stepwise manner to assess the relation between this IPF cut off and modMACE as well as other established risk factors (inclusion if p<0.05). Preoperatively, there were no differences in IPF between patients with and without modMACE (3.1% [2.2% – 4.7%](median [interquartile range]) vs. 2.8% [1.9% – 4.3%]. Patients with modMACE (28 of 730 patients; 3.8%) had higher IPF values in the PACU compared to patients without modMACE (3.6% [2.6–6%] vs. 2.9% [2–4.4%]; p=0.011). The optimal cut off of IPF > 5.4% was associated with an increased risk for modMACE after adjustment for covariates (hazard ratio: 2.528; 95% confidence interval: 1.156 to 5.528, p=0.02). In conclusion, IPF is an independent predictor of modMACE after surgery and might improve risk stratification of surgical patients.

Institution where the work was performed and funded: Klinikum rechts der Isar der Technischen Universität München, Ismaningerstr. 22, 81675 Munich, Germany.

Microfludic platforms for the evaluation of anti-platelet agent efficacy under hyper-shear conditions associated with ventricular assist devices

Thrombus formation is a major adverse event affecting patients implanted with ventricular assist devices (VADs). Despite anti-thrombotic drug administration, thrombotic events remain frequent within the first year post-implantation. Platelet activation (PA) is an essential process underling thrombotic adverse events in VAD systems. Indeed, abnormal shear forces, correlating with specific flow trajectories of VADs, are strong agonists mediating PA. To date, the ability to determine efficacy of anti-platelet (AP) agents under shear stress conditions is limited. Here, we present a novel microfluidic platform designed to replicate shear stress patterns of a clinical VAD, and use it to compare the efficacy of two AP agents in vitro. Gel-filtered platelets were incubated with i) acetylsalicylic acid (ASA) and ii) ticagrelor, at two different concentrations (ASA: 125 and 250 µM; ticagrelor: 250 and 500 nM) and were circulated in the VAD-emulating microfluidic platform using a peristaltic pump. GFP was collected after 4 and 52 repetitions of exposure to the VAD shear pattern and tested for shear-mediated PA. ASA significantly inhibited PA only at 2-fold higher concentration (250 µM) than therapeutic dose (125 µM). The effect of ticagrelor was not dependent on drug concentration, and did not show significant inhibition with respect to untreated control. This study demonstrates the potential use of microfluidic platforms as means of testing platelet responsiveness and AP drug efficacy under complex and realistic VAD-like shear stress conditions.

Evaluation of Complete Blood Count Indices (NLR, PLR, MPV/PLT, and PLCRi) in Healthy Dogs, Dogs With Periodontitis, and Dogs With Oropharyngeal Tumors as Potential Biomarkers of Systemic Inflammatory Response

The aim of the study was to retrospectively assess complete blood count (CBC) indices of dogs with periodontitis (PD; n = 73) and dogs with oropharyngeal tumors (OT; n = 92) in comparison to CBC indices of healthy dogs (HD; n = 71). Neutrophil to lymphocyte ratio (NLR), platelet to lymphocyte ratio, mean platelet volume to platelet ratio, and platelet large cell ratio index (PLCRi) were evaluated as biomarkers of systemic inflammatory response provoked by PD and OT. Results of multivariable polytomous logistic regression analysis indicated no significant associations between CBC indices and PD. Both NLR and PLCRi were significantly higher in dogs with OT when compared to HD and dogs with PD and could, therefore, indicate a tumor-associated systemic inflammatory response. Additional studies of CBC indices, along with other biomarkers of systemic inflammatory response, are recommended to validate them as reliable indicators of clinical disease activity.

Platelet reactivity in sepsis syndrome: results from the PRESS study

Platelet activation mediates systemic inflammatory response during infection. However, data on platelet reactivity (PR) varies among different settings. We assessed PR along different stages of sepsis and tried to predict for determinants of its variance. In parallel, we evaluated it as an early bedside diagnostic biomarker. This was an observational prospective cohort study. Incoming patients were assorted to distinct groups of uncomplicated infection, sepsis, and severe sepsis/septic shock. A control group of healthy volunteers was used as comparison. PR was assessed using the bedside point-of-care VerifyNow assay, in P2Y₁₂ reaction units (PRU) alongside with levels of major inflammatory markers and whole blood parameters. A total of 101 patients and 27 healthy volunteers were enrolled. PR significantly and reversibly increases during sepsis compared to uncomplicated infection and healthy controls (244 ± 66.7 vs 187.33 ± 60.98, p < 0.001 and 192.17 ± 47.51, p < 0.001, respectively). In severe sepsis, PR did not significantly differ compared to other groups. Sepsis stage uniquely accounts for 15.5% of PR in a linear regression prediction model accounting for 30% of the variance of PR (F = 8.836, p < 0.001). PRU >253 had specificity of 91.2% and sensitivity of 40.8% in discriminating septic from non-septic patients. The addition of PRU to SOFA and qSOFA scores significantly increased their c-statistic (AUC SOFA + PRU, 0.867 vs SOFA, 0.824, p < 0.003 and AUC qSOFA + PRU, 0.842 vs qSOFA, 0.739, p < 0.001), making them comparable (AUC SOFA + PRU vs qSOFA + PRU, p = 0.4). PR significantly and reversibly increases early in sepsis, but seems to exhaust while disease progresses. Bedside assessment of PR can provide robust discriminative accuracy in the early diagnosis of septic patients.

A pilot study evaluating the prognostic utility of platelet indices in dogs with septic peritonitis

OBJECTIVE

To characterize platelet indices at time of diagnosis of septic peritonitis in dogs and to assess the relationship between platelet parameter data and survival to discharge in dogs treated surgically.

DESIGN

Retrospective, observational, descriptive pilot study from 2009 to 2014.

SETTING

University teaching hospital.

ANIMALS

Forty-eight dogs diagnosed with septic peritonitis were included in this study. Thirty-six dogs had surgical source control. Blood samples from 46 healthy control dogs were used for reference interval (RI) generation.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Dogs with septic peritonitis had significantly increased mean values for mean platelet volume (MPV), plateletcrit (PCT), and platelet distribution width (PDW) with increased proportions of dogs having values above the RI compared to healthy dogs. A significantly increased proportion of dogs with septic peritonitis had platelet counts above (12.5%) and below (8.3%) the RI, with no significant difference in mean platelet count compared to healthy dogs. No significant differences in the mean platelet count, MPV, PCT, or PDW were found between survivors and nonsurvivors in dogs with surgical source control; however, dogs with MPV values above the RI had significantly increased mortality compared to dogs within the RI (P = 0.025). Values outside the RI for other platelet parameters were not associated with significant differences in mortality.

CONCLUSIONS

Dogs with septic peritonitis have increased frequency of thrombocytosis and thrombocytopenia with increased MPV, PCT, and PDW. An increased MPV may be a useful indicator of increased risk of mortality in dogs treated surgically.

Acute effects of 30 minutes of exposure to a smartphone call on in vitro platelet function

BACKGROUND

Significant concerns are now regularly raised about the safety of excessive mobile phone use. This study was aimed to assess the acute effects of radiofrequency waves emitted by a commercial smartphone on platelet function.

MATERIALS AND METHODS

Two sequential citrated blood samples were collected from 16 healthy volunteers recruited from laboratory staff. The first sample was placed in a plastic rack, 1 cm distant from a commercial smartphone receiving a 30-min call and emitting 900 MHz radiofrequency waves. The second sample was placed in another plastic rack, isolated from radiofrequency wave sources, for the same period. The platelet count and the mean platelet volume were then assessed in all blood samples, whereas platelet function was evaluated using the platelet function analyser-100 (PFA-100).

RESULTS

A 30-min exposure of citrated blood to smartphone radiofrequency waves induced significant prolongation of collagen-epinephrine aggregation (median increase, 10%) and a considerable increase of mean platelet volume (median increase, 5%), whereas collagen-adenosine diphosphate aggregation and platelet count remained unchanged.

DISCUSSION

This study demonstrates that smartphone radiofrequency waves induce significant perturbation of platelet structure and function, thus providing further support to concerns regarding excessive use of mobile phones. Caution should also be taken with regards to blood products containing platelets, which should be kept far away from mobile phones and smartphones throughout the production pipeline and storage period.

Elevated mean platelet volume is associated with poor outcome after mechanical thrombectomy

Background

Elevated mean platelet volume (MPV), indicating higher platelet activity, could be a predictor of prognosis in patients with acute ischemic stroke receiving medical therapy.

Objective

To investigate the relationship between MPV and functional outcome in patients with acute anterior circulation stroke 3 months after undergoing mechanical thrombectomy (MT).

Methods

A total of 153 consecutive patients with acute stroke following MT, in two separate stroke centers, were enrolled between May 2013 and March 2016. MPV was measured on admission. Subjects were divided into two groups according to average MPV level. Univariate and multivariate analyses were performed. MPV was also incorporated into the Houston IA Therapy (HIAT) score, which was developed as a scoring system to predict poor prognosis, and the prediction capability was compared with the HIAT score alone.

Results

The average MPV was 10.4 fL. Patients with high MPV had a significantly lower rate of functional independence (28.9% vs 57.1%, p=0.000). After multivariable analysis, elevated MPV remained an independent predictor of unfavorable outcome (OR=3.93, 95% CI 1.73 to 8.94, p=0.001). When the MPV cut-off value was set at 10.4 fL using the receiver operating characteristic (ROC) analysis, MPV ≥10.4 fL predicted unfavorable outcome with 62.1% sensitivity and 66.7% specificity, respectively. Addition of MPV to the HIAT score did not improve predictive power compared with the HIAT score system alone by a comparison of the areas under the two ROC curves (0.70 vs 0.62, p=0.174).

Conclusions

Elevated MPV is an independent predictor of poor outcome in patients with acute anterior circulation stroke undergoing MT at 3 months.

Mean Platelet Volume and Arterial Stiffness - Clinical Relationship and Common Genetic Variability

Vessel wall stiffening is an important clinical parameter, but it is unknown whether platelets, key elements in the pathogenesis of arterial thrombosis, are associated with arterial stiffness. The present studies sought to determine whether mean platelet volume (MPV), a potential marker of platelet activation, is linked to vascular elasticity as assessed by the augmentation index (AIx), in 15,010 individuals from the population-based Gutenberg Health Study. Multivariable analysis showed that MPV in both males (β 0.776; 95^thCI [0.250;1.16]; p = 0.0024) and females (β 0.881[0.328;1.43]; p = 0.0018) is strongly associated with AIx. Individuals with MPV and AIx above the sex-specific medians had worse survival. Association analysis between MPV-related genetic variants and arterial stiffness identified four genetic variants in males and one in females related with AIx. Cox regression analysis for mortality identified one of these joint genetic variants close to ring finger protein 145 gene (RNF145, rs10076782) linked with increased mortality (hazard ratio 2.02; 95^thCI [1.35;3.02]; p = 0.00061). Thus, these population-based data demonstrate a close relation between platelet volume as a potential marker of platelet activation and arterial stiffness in both sexes. Further research is warranted to further elucidate the mechanisms underlying larger platelets‘ role in arterial stiffening including the role of shared common genetics.