The role of platelets in atherothrombosis

Systemic inflammation index as useful tool to predict arteriovenous graft stenosis: Our experience and literature review

OBJECTIVE

Many studies show that settings of severe inflammatory stress might be responsible for changes in circulating blood cells count. Effective inflammation indices are created calculating the quantitative relationship between these cells. No previous studies have been proposed on hemodialysis patients exploring the association between arteriovenous graft (AVG) stenosis and systemic inflammation markers, such as Neutrophil-lymphocyte ratio (NLR), platelet-lymphocyte ratio (PLR), and systemic-immune-inflammation index (SII).

METHODS

Patients undergone surgery for AVG creation in a 2-year period are examined. Examining their full blood count, we have established the value of inflammatory indices (NLR, PLR, SII) and we have compared their mean values in patients who have developed significant stenosis or not. Finally, we have considered the connection between those values and stenosis onset and recurrence in AVG.

RESULTS

Fifty-two patients are included in the study [male: 40%, mean age 70 ± 15 years (range 55-86)]. We have found out there is not statistical significance in preoperative values of inflammatory index (NLR p 0.33, PLR p 0.15, SII p 0.98) Otherwise NLR and SII indices were statistically significant 3 months after surgery (NLR 2.04 ± 0.98 vs 3.91 ± 2.10, p < 0.001; SII 415.32 ± 255.15 vs 636.91 ± 349.01, p 0.014).

CONCLUSIONS

Increased post-operative values of NLR and SII have proved a strong association with AVG outflow stenosis onset and recurrence.

The effect of IL17 and IL23 inhibitors on hematological parameters and C-reactive protein in psoriasis patients

INTRODUCTION

In the quest for objective biomarkers for psoriasis, the neutrophil/lymphocyte ratio (NLR), platelet/lymphocyte ratio (PLR), C-reactive protein (CRP), and mean platelet volume (MPV) have been used to assess disease severity, treatment efficacy, and follow-up in psoriasis, and their relationship with the Psoriasis Area Severity Index (PASI) has been investigated.

PURPOSE

The evaluation of pre-treatment, 3rd and 6th-month levels of NLR, PLR, MPV, and CRP along with PASI scores in psoriasis patients treated with secukinumab, ixekizumab, risankizumab, and guselkumab.

MATERIALS AND METHODS

In our study, 83 patients aged 18 and over, who were followed up with moderate-severe plaque type psoriasis vulgaris and psoriatic arthritis and received secukinumab, ixekizumab, risankizumab, and guselkumab treatment in the chronic skin diseases clinic of Fırat University Faculty of Medicine Hospital between January 2019 and 2023, were evaluated retrospectively.

RESULTS

Post-treatment leukocyte, neutrophil, lymphocyte, platelet, CRP, and PASI values were statistically significantly lower in all biological agent groups and all patients. The post-treatment NLR value was statistically significantly higher in all patients and in the group using ixekizumab. The post-treatment PLR value was statistically significantly higher in the group using guselkumab and ixekizumab and in all patients. The post-treatment MPV was statistically significantly higher in all patients and in the group using secukinumab. No correlation was found between post-treatment PASI and other values (p > 0.05). There was no statistically significant difference between the post-treatment 6-month values among all biological agent groups. The effects of different drugs on outcomes after treatment were found to be similar (p > 0.05).

CONCLUSION

Our study supports the view that MPV and CRP can be used in patients with psoriasis using IL17 and IL23 inhibitors, while NLR and PLR parameters derived from blood count may not be used to evaluate treatment response, contrary to other studies.

Biochemical Properties and Antithrombotic Effect of a Serine Protease Isolated from the Medicinal Mushroom Pycnoporus coccineus (Agaricomycetes)

The purification of a fibrinolytic enzyme from the fruiting bodies of wild-growing medicinal mushroom, Pycnoporus coccineus was achieved through a two-step procedure, resulting in its homogeneity. This purification process yielded a significant 4.13-fold increase in specific activity and an 8.0% recovery rate. The molecular weight of P. coccineus fibrinolytic enzyme (PCFE) was estimated to be 23 kDa using sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis. PCFE demonstrated its optimal activity at a temperature of 40 °C and pH 8. Notably, the enzymatic activity was inhibited by the presence of zinc or copper metal ions, as well as serine protease inhibitors, such as phenylmethylsulfonyl fluoride and 4-amidinophenylmethanesulfonyl fluoride. PCFE exhibited remarkable specificity towards a synthetic chromogenic substrate for thrombin. The enzyme demonstrated the Michaelis-Menten constant (Km), maximal velocity (V ), and catalytic rate constant (Kcat) values of 3.01 mM, 0.33 mM min-1 μg-1, and 764.1 s-1, respectively. In vitro assays showed PCFE's ability to effectively degrade fibrin and blood clots. The enzyme induced alterations in the density and structural characteristics of fibrin clots. PCFE exhibited significant effects on various clotting parameters, including recalcification time, activated partial thromboplastin time, prothrombin time, serotonin secretion from thrombin-activated platelets, and thrombin-induced acute thromboembolism. These findings suggest that P. coccineus holds potential as an antithrombotic biomaterials and resources for cardiovascular research.

Thrombocytes and Platelet-Rich Plasma as Modulators of Reproduction and Fertility

Thrombocytes play an essential role in hemostasis and thrombosis. Moreover, the controlled activation of thrombocytes is required in reproduction and fertility. The platelet-activating factor and the controlled activation of platelets have important roles in folliculogenesis, ovulation, placental development, implantation and embryo development. Activated platelets accumulate in the follicular vessels surrounding the follicle and, due to its released soluble molecules (factors, mediators, chemokines, cytokines, neurotransmitters), locally increase oocyte maturation and hormone secretion. Furthermore, activated platelets are involved in the pathogenesis of ovarian hyperstimulation syndrome (OHSS) and preeclampsia. Low-dose aspirin can prevent OHSS during ovulation induction, while intrauterine or intraovarian administration of platelet-rich plasma (PRP) increases the endometrium thickness and receptivity as well as oocyte maturation. Activated thrombocytes rapidly release the contents of intracellular granules and have multiple adhesion molecules and receptors on their surface. Considering the numerous homeostatic endocrine functions of thrombocytes, it is reasonable to suppose a platelet-associated regulatory system (PARS) in reproduction. Although we are far from a complete understanding of the regulatory processes, the results of PARS research and the therapeutic application of aspirin and PRP during in vitro fertilization are promising.

Relationship of Complete Blood Count Derived Biomarkers With Methotrexate Resistance

Background Rheumatoid arthritis (RA) is an autoimmune disease characterized by chronic inflammation and joint damage. Among the therapeutic agents, methotrexate remains a cornerstone of initial treatment. Complete blood count (CBC)-derived biomarkers such as neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), monocyte-to-lymphocyte ratio (MLR), systemic immune-inflammation index (SII), and systemic immune response index (SIRI) have been extensively studied in various diseases. Still, their specific role in RA patients undergoing methotrexate treatment has not been investigated. Objective This study aimed to investigate the relationship of CBC-derived biomarkers with methotrexate resistance in newly diagnosed rheumatoid arthritis patients. Methods We performed a comprehensive analysis of 54 RA patients, divided into methotrexate-resistant (MTXR) and methotrexate-sensitive (MTXS) groups. Analysis of variance (ANOVA) was used to assess differences in hematological biomarkers between groups. Standard t-tests were used to compare specific biomarkers between the MTXR and MTXS groups. The chi-squared test was used to compare categorical variables between groups. Pearson's correlation test was also used to examine correlations between these biomarkers and Disease Activity Score 28 (DAS28) in both groups. Receiver operating characteristic (ROC) curve analysis was performed for each biomarker to determine predictive ability. Results A statistically increased PLR ratio was observed in the MTXR group compared to the MTXS group. Significant correlations between DAS28 and NLR, PLR, SII, and SIRI were observed in the MTXR group. In contrast, these correlations were absent in the MTXS group. In addition to PLR, DAS28 and ESR were significantly higher in the MTXR group than in the MTXS group. None of these biomarkers showed prognostic value for methotrexate treatment outcomes. Conclusion PLR could be used as a biomarker for resistance to methotrexate treatment in a specific RA patient population. Increased PLR and ESR, together with higher DAS28, might be associated with a more pronounced inflammatory state in MTXR patients.

Elevated plasma leptin levels are associated with vascular access dysfunction in patients on maintenance hemodialysis

BACKGROUND

Inflammation has been associated with vascular access (VA) dysfunction. The adipocytokine leptin can directly induce pro-inflammatory T helper 1 immune responses and the pathogenesis of chronic inflammation. We explored the association between plasma leptin and VA dysfunction in patients on maintenance hemodialysis (HEMO).

METHODS

A total of 344 consecutive patients who received anastomosis for VA at a single HEMO center between June 1, 2010 and December 31, 2021 were screened. Of these patients, 267 met the inclusion criteria and were included. ELISA was used to measure circulating levels of leptin.

RESULTS

The VA dysfunction group had a higher leptin level than the patent VA group. A higher concentration of leptin was independently and significantly associated with an elevated risk of VA dysfunction. Multiple logistic regression analysis showed that leptin, female sex, and hypertension were independently associated with VA dysfunction, even after adjusting for known biomarkers. We then evaluated the ability of leptin, female sex, and hypertension to predict the risk of VA dysfunction, and the area under the curve (AUC) for leptin was 0.626 (p = 0.0001). When leptin, female sex, and hypertension were added to this multivariate model, the AUC increased to 0.679 (p = 0.001) for leptin and hypertension, and 0.690 for leptin, hypertension, and female sex (p = 0.004). In addition, plasma leptin levels were associated with sex, body mass index, and hemoglobin.

CONCLUSIONS

In addition to the association between leptin and VA dysfunction, hypertension and female sex independently predicted VA dysfunction in patients with HEMO.

Current concepts and novel targets for antiplatelet therapy

Platelets have a crucial role in haemostasis and atherothrombosis. Pharmacological control of platelet hyper-reactivity has become a cornerstone in the prevention of thrombo-ischaemic complications in atherosclerotic diseases. Current antiplatelet therapies substantially improve clinical outcomes in patients with coronary artery disease, but at the cost of increased risk of bleeding. Beyond their role in thrombosis, platelets are known to regulate inflammatory (thrombo-inflammatory) and microcirculatory pathways. Therefore, controlling platelet hyper-reactivity might have implications for both tissue inflammation (myocardial ischaemia) and vascular inflammation (vulnerable plaque formation) to prevent atherosclerosis. In this Review, we summarize the pathophysiological role of platelets in acute myocardial ischaemia, vascular inflammation and atherosclerotic progression. Furthermore, we highlight current clinical concepts of antiplatelet therapy that have contributed to improving patient care and have facilitated more individualized therapy. Finally, we discuss novel therapeutic targets and compounds for antiplatelet therapy that are currently in preclinical development, some of which have a more favourable safety profile than currently approved drugs with regard to bleeding risk. These novel antiplatelet targets might offer new strategies to treat cardiovascular disease.

Long-term arteriovenous fistula prognosis for maintenance hemodialysis patients who accepted PIRRT by using arteriovenous fistula

BACKGROUND

Maintenance hemodialysis (MHD) patients are often admitted to the hospital for severe morbidities. Prolonged intermittent renal replacement therapy (PIRRT) is required during the hospital staying. There are controversial opinions on the use of arteriovenous fistula (AVF) as vascular access for PIRRT in MHD patients.

METHODS

Patients with AVF who accepted PIRRT in our center between January 2014 and June 2021 were retrospectively screened. AVF dysfunction and patient mortality were assessed as endpoints. Univariate and multivariate regression models were employed to identify the risk factors of AVF dysfunction.

RESULTS

About 162 patients were included in our present study. Twenty-six experienced AVF dysfunction, of whom 53.8%, 19.2%, and 27.0% had percutaneous transluminal balloon angioplasty, surgical revision, and AVF reconstruction, respectively. The accumulated AVF dysfunction rates were 11.8%, 16.2%, and 21.0% in 1, 2, and 3 years, respectively. Multivariate analysis revealed that smoking (HR 2.750, 95% CI 1.181-6.402, p = 0.019), higher platelet (PLT, HR 1.009, 95% CI 1.000-1.017, p = 0.047), higher prothrombin activity (PTA, HR 1.039, 95% CI 1.012-1.066, p = 0.004), and lower diastolic blood pressure (DBP, HR 0.963, 95% CI 0.932-0.996, p = 0.026) were independent risk factors for AVF dysfunction. During the follow-up period, 37 patients died.

CONCLUSIONS

Overall, the use of AVF for PIRRT might not dramatically increase the incidence of AVF dysfunction. And, Smoking, lower DBP, higher PLT, and higher PTA were associated with increased AVF dysfunction.

Monoglyceride Lipase Deficiency Is Associated with Altered Thrombogenesis in Mice

Monoglyceride lipase (MGL) hydrolyzes monoacylglycerols (MG) to glycerol and one fatty acid. Among the various MG species, MGL also degrades 2-arachidonoylglycerol, the most abundant endocannabinoid and potent activator of the cannabinoid receptors 1 and 2. We investigated the consequences of MGL deficiency on platelet function using systemic (Mgl-/-) and platelet-specific Mgl-deficient (platMgl-/-) mice. Despite comparable platelet morphology, loss of MGL was associated with decreased platelet aggregation and reduced response to collagen activation. This was reflected by reduced thrombus formation in vitro, accompanied by a longer bleeding time and a higher blood volume loss. Occlusion time after FeCl3-induced injury was markedly reduced in Mgl-/- mice, which is consistent with contraction of large aggregates and fewer small aggregates in vitro. The absence of any functional changes in platelets from platMgl-/- mice is in accordance with lipid degradation products or other molecules in the circulation, rather than platelet-specific effects, being responsible for the observed alterations in Mgl-/- mice. We conclude that genetic deletion of MGL is associated with altered thrombogenesis.

Prediction of Poor Outcome after Successful Thrombectomy in Patients with Severe Acute Ischemic Stroke: A Pilot Retrospective Study

Several baseline hematologic and metabolic laboratory parameters have been linked to acute ischemic stroke (AIS) clinical outcomes in patients who successfully recanalized. However, no study has directly investigated these relationships within the severe stroke subgroup. The goal of this study is to identify potential predictive clinical, lab, and radiographic biomarkers in patients who present with severe AIS due to large vessel occlusion and have been successfully treated with mechanical thrombectomy. This single-center, retrospective study included patients who experienced AIS secondary to large vessel occlusion with an initial NIHSS score ≥ 21 and were recanalized successfully with mechanical thrombectomy. Retrospectively, demographic, clinical, and radiologic data from electronic medical records were extracted, and laboratory baseline parameters were obtained from emergency department records. The clinical outcome was defined as the modified Rankin Scale (mRS) score at 90 days, which was dichotomized into favorable functional outcome (mRS 0-3) or unfavorable functional outcome (mRS 4-6). Multivariate logistic regression was used to build predictive models. A total of 53 patients were included. There were 26 patients in the favorable outcome group and 27 in the unfavorable outcome group. Age and platelet count (PC) were found to be predictors of unfavorable outcomes in the multivariate logistic regression analysis. The areas under the receiver operating characteristic (ROC) curve of models 1 (age only model), 2 (PC only model), and 3 (age and PC model) were 0.71, 0.68, and 0.79, respectively. This is the first study to reveal that elevated PC is an independent predictor of unfavorable outcomes in this specialized group.

Correlation analysis of carotid plaque in young patients with newly diagnosed type 2 diabetes and platelet-to-lymphocyte ratio and neutrophil-lymphocyte ratio

OBJECTIVE

Platelet-to-lymphocyte ratio (PLR) and neutrophil-lymphocyte ratio (NLR) have been reported to be related to atherosclerosis. The relationship between PLR, NLR, and carotid atherosclerotic plaque in young patients with newly diagnosed type 2 diabetes has not been clinically reported. This study aimed to analyze the relationship between PLR, NLR, and carotid plaques in young patients with newly diagnosed type 2 diabetes.

METHOD

The total 268 patients were divided into the intima-media-thickening (IMT) group (116 cases) and plaque group (152 cases). The plaque group was divided into grade I (62 cases), grade II (47 cases), and grade III groups (43 cases). The counts of platelets, neutrophils, and lymphocytes were determined.

RESULTS

The diagnostic effect of PLR and NLR was evaluated by the receiver-operating characteristic curve (ROC) and areas under the curve (AUC). The PLR and NLR values in the observation group were higher than those in the control group; these two values in the plaque group were also higher than those in the IMT group. The two values in the grade III plaque group were higher than those in grade II. The values in the grade II plaque group were also higher than those in the grade I plaque group. The ROC of PLR and NLR were 0.722 and 0.653, and the AUC of PLR and NLR were 111.086 and 2.240. PLR yielded a sensitivity of 0.789 and a specificity of 0.612. Neutrophil-lymphocyte ratio yielded a sensitivity of 0.809 and a specificity of 0.511.

CONCLUSION

The PLR and NLR may be related to carotid inflammation in patients and positively correlated with carotid plaque.

Early aspirin use and the development of cardiac allograft vasculopathy in pediatric heart transplant recipients: A pediatric heart transplant society analysis

BACKGROUND

Cardiac allograft vasculopathy (CAV) remains a leading cause of graft loss in pediatric heart transplant (HTx) recipients. Adult literature suggests that aspirin (ASA) use in the early post-HTx period may reduce the risk of CAV. This study aimed to determine the impact of early ASA use on the development of CAV in pediatric HTx recipients.

METHODS

All subjects <17 years of age at time of primary HTx who survived ≥3 years without evidence of CAV were identified for inclusion from the Pediatric Heart Transplant Society database (1996-2019). Early ASA use was defined as ASA started within the first 3 years post-HTx and was classified as continuous or intermittent. Frequency of ASA use was described across centers. Kaplan-Meier method assessed freedom from CAV and overall graft survival. Multiphase parametric hazard analyses and propensity score matched analysis were used to identify independent risk factors.

RESULTS

3,011 patients were included with 387 (13%) receiving continuous ASA, 676 (22%) receiving intermittent ASA, and 1,948 (65%) receiving no ASA. ASA use was highly variable across centers (0%-100%). At baseline patients receiving continuous ASA therapy demonstrated inferior graft survival (p < 0.001) and worse freedom from CAV (p = 0.002), but with lower CAV grades (p = 0.05). In multiphase parametric hazard modeling continuous ASA use was not independently associated with CAV, but remained associated with inferior graft survival. Propensity-matched sub-analysis between continuous and no ASA groups demonstrated no difference in freedom from CAV or overall graft loss.

CONCLUSIONS

ASA use varies widely across pediatric HTx centers. Early ASA use did not reduce the risk of CAV or graft loss in pediatric heart transplant recipients.

Effect of antiplatelet agents on Escherichia coli sepsis mechanisms: A review

Despite ever-increasing improvements in the prognosis of sepsis, this condition remains a frequent cause of hospitalization and mortality in Western countries. Sepsis exposes the patient to multiple complications, including thrombotic complications, due to the ability of circulating bacteria to activate platelets. One of the bacteria most frequently implicated in sepsis, Escherichia coli, a Gram-negative bacillus, has been described as being capable of inducing platelet activation during sepsis. However, to date, the mechanisms involved in this activation have not been clearly established, due to their multiple characteristics. Many signaling pathways are thought to be involved. At the same time, reports on the use of antiplatelet agents in sepsis to reduce platelet activation have been published, with variable results. To date, their use in sepsis remains controversial. The aim of this review is to summarize the currently available knowledge on the mechanisms of platelet activation secondary to Escherichia coli sepsis, as well as to provide an update on the effects of antiplatelet agents in these pathological circumstances.

Effect of Mean Platelet Volume to Platelet Count Ratio on Mortality in Peritoneal Dialysis

Background and Aims

Mean platelet volume to platelet count ratio (MPV/PC) has been found to be an independent risk factor for mortality in various diseases, including cardiovascular disease, cancer, and hemodialysis. We aimed to evaluate the association between MPV/PC and all-cause and cardiovascular (CV) mortality in peritoneal dialysis (PD) patients.

Methods and Results

We conducted a retrospective cohort study at a single center and enrolled 1473 PD patients who were catheterized at our PD center from January 1, 2006, to December 31, 2013. All patients were divided into four groups according to the quartiles of baseline MPV/PC levels and followed up until December 31, 2018. A total of 453 patients died, and 221 deaths were caused by cardiovascular disease during a median follow-up time of 48.0 (21.9-82.2) months. There was a significant interaction by age of association between MPV/PC level and all-cause mortality (P = 0.009), and multivariate Cox regression analysis showed that higher MPV/PC level was related to a decreased risk of all-cause and CV mortality in PD patients aged < 60 years (HR = 0.62, 95%CI = 0.40 − 0.96, P = 0.032; HR = 0.49, 95%CI = 0.26 − 0.93, P = 0.029, respectively), rather than in patients aged ≥ 60 years (HR = 1.37, 95%CI = 0.84 − 2.22, P = 0.208; HR = 1.50, 95%CI = 0.77 − 2.92, P = 0.237, respectively).

Conclusion

Our results indicated that low MPV/PC level was an independent risk factor for all-cause and CV mortality in PD patients aged less than 60 years.

Platelet-Derived Exosomes in Atherosclerosis

Atherosclerosis (AS), the main cause of many cardiovascular diseases (CVDs), is a progressive inflammatory disease characterized by the accumulation of lipids, fibrous elements, and calcification in the innermost layers of arteries. The result is the thickening and clogging of these vessel walls. Several cell types are directly involved in the pathological progression of AS. Among them, platelets represent the link between AS, inflammation, and thrombosis. Indeed, besides their pivotal role in hemostasis and thrombosis, platelets are key mediators of inflammation at injury sites, where they act by regulating the function of other blood and vascular cell types, including endothelial cells (ECs), leukocytes, and vascular smooth muscle cells (VSMCs). In recent years, increasing evidence has pointed to a central role of platelet-derived extracellular vesicles (P-EVs) in the modulation of AS pathogenesis. However, while the role of platelet-derived microparticles (P-MPs) has been significantly investigated in recent years, the same cannot be said for platelet-derived exosomes (P-EXOs). For this reason, this reviews aims at summarizing the isolation methods and biological characteristics of P-EXOs, and at discussing their involvement in intercellular communication in the pathogenesis of AS. Evidence showing how P-EXOs and their cargo can be used as biomarkers for AS is also presented in this review.

Chronic inflammation, cancer development and immunotherapy

Chronic inflammation plays a pivotal role in cancer development. Cancer cells interact with adjacent cellular components (pro-inflammatory cells, intrinsic immune cells, stromal cells, etc.) and non-cellular components to form the inflammatory tumor microenvironment (TME). Interleukin 6 (IL-6), macrophage migration inhibitory factor (MIF), immune checkpoint factors and other pro-inflammatory cytokines produced by intrinsic immune cells in TME are the main mediators of intercellular communication in TME, which link chronic inflammation to cancer by stimulating different oncogenic signaling pathways and improving immune escape to promote cancer development. In parallel, the ability of monocytes, T regulatory cells (Tregs) and B regulatory cells (Bregs) to perform homeostatic tolerogenic functions is hijacked by cancer cells, leading to local or systemic immunosuppression. Standard treatments for advanced malignancies such as chemotherapy and radiotherapy have improved in the last decades. However, clinical outcomes of certain malignant cancers are not satisfactory due to drug resistance and side effects. The clinical application of immune checkpoint therapy (ICT) has brought hope to cancer treatment, although therapeutic efficacy are still limited due to the immunosuppressive microenvironment. Emerging evidences reveal that ideal therapies including clearance of tumor cells, disruption of tumor-induced immunosuppression by targeting suppressive TME as well as reactivation of anti-tumor T cells by ICT. Here, we review the impacts of the major pro-inflammatory cells, mediators and their downstream signaling molecules in TME on cancer development. We also discuss the application of targeting important components in the TME in the clinical management of cancer.

Assessment of Red Cell Distribution Width, Platelet/lymphocyte Ratio, Systemic Immune-inflammation Index, and Neutrophil/lymphocyte Ratio Values in Patients with Central Retinal Artery Occlusion

PURPOSE

To evaluate complete blood count (CBC)-derived inflammatory indices in central retinal artery occlusion (CRAO).

METHODS

A total of 42 patients with CRAO (CRAO group) and 42 age- and sex-matched subjects without CRAO (Control group) were included. CBC parameters including red cell distribution width (RDW) levels were assayed. Platelet/lymphocyte ratio (PLR), systemic immune-inflammation index (SII) and neutrophil/ lymphocyte ratio (NLR) were calculated.

RESULTS

RDW, PLR, SII and NLR values were significantly higher in CRAO group than control group [15.2 ± 1.47% vs 13.96 ± 1.13% (p < .001), 127.94 ± 48.21 vs 101.16 ± 24.84 (p = .008), 667.11 ± 357.84 vs 493.44 ± 207.07 (p = .008), 2.70 ± 1.27 vs 2.13 ± 0.83 (p = .018), respectively]. In multivariate analysis only RDW was independent predictor for CRAO (OR 2.317, p < .001). On ROC analysis, area under curve of RDW, PLR, SII, and NLR for CRAO were 0.761, 0.685, 0.622 and 0.618, respectively.

CONCLUSION

RDW seems superior to other inflammatory indices to predict CRAO.

Functional analysis and expression profile of human platelets infected by EBV in vitro

Platelet activation is commonly detected after infection by multiple viruses such as human immunodeficiency virus (HIV), H1N1 influenza, Hepatitis C virus (HCV), Ebola virus (EBV), and Dengue virus (DENV). Non-coding RNAs (ncRNAs) constitute the majority of the human transcribed genome, but the biology of platelet ncRNAs is largely unexplored. In this study, we performed microarray profiling to characterize the expression profile of human platelets infected with EBV in vitro after 2 h. A total of 187 long non-coding RNAs (lncRNAs) displayed differences, of which 114 were upregulated and 73 were downregulated; 78 microRNAs (miRNAs) showed differences, including 73 upregulated and 5 downregulated; 808 mRNAs displayed differences, among which 367 were upregulated and 441 were downregulated. Gene ontology (GO) analysis mostly related to G protein-coupled receptor signaling pathway, detection of chemical stimulus involved in sensory perception of smell and regulation of transcription by RNA polymerase II. Pathway analysis showed that the differentially expressed genes were mainly enriched in cell metabolism and immune-related response. A ceRNA network was established based on predicting regulatory pairs in differentially expressed genes, in which hsa-miR-6877-3p had the highest regulatory capability (degree = 31), FAM230A was the lncRNA with the highest regulatory capability (degree = 28). According to the EBV related miRNA regulation network, it revealed that ebv-miR-BART19-3p had the most target genes and BRWD1, FAM126B, TFRC and JMY were the genes most regulated by EBV-related miRNAs. After overlapping the three networks, we found that the EIFAK2 gene was strongly correlated with autologous ncRNAs, including hsa-miR-1972, hsa-miR-504-3p and hsa-miR-6825-5p, as well as with EBV ncRNAs, including EBER1, EBER2, miR-BART7-3p and miR-BART16. The present study contributes to a better understanding of the expression profiling of ncRNAs and their functions in platelets activated by EBV in vitro, and paves the way to further study on platelet function.

Beyond the thrombus: Platelet-inspired nanomedicine approaches in inflammation, immune response, and cancer

The traditional role of platelets is in the formation of blood clots for physiologic (e.g., in hemostasis) or pathologic (e.g., in thrombosis) functions. The cellular and subcellular mechanisms and signaling in platelets involved in these functions have been extensively elucidated and new knowledge continues to emerge, resulting in various therapeutic developments in this area for the management of hemorrhagic or thrombotic events. Nanomedicine, a field involving design of nanoparticles with unique biointeractive surface modifications and payload encapsulation for disease-targeted drug delivery, has become an important component of such therapeutic development. Beyond their traditional role in blood clotting, platelets have been implicated to play crucial mechanistic roles in other diseases including inflammation, immune response, and cancer, via direct cellular interactions, as well as secretion of soluble factors that aid in the disease microenvironment. To date, the development of nanomedicine systems that leverage these broader roles of platelets has been limited. Additionally, another exciting area of research that has emerged in recent years is that of platelet-derived extracellular vesicles (PEVs) that can directly and indirectly influence physiological and pathological processes. This makes PEVs a unique paradigm for platelet-inspired therapeutic design. This review aims to provide mechanistic insight into the involvement of platelets and PEVs beyond hemostasis and thrombosis, and to discuss the current state of the art in the development of platelet-inspired therapeutic technologies in these areas, with an emphasis on future opportunities.

Chemokine PF4 Inhibits EV71 and CA16 Infections at the Entry Stage

Platelet factor 4 (PF4) or the CXC chemokine CXCL4 is the most abundant protein within the α-granules of platelets. Previous studies found that PF4 regulates infections of several viruses, including HIV-1, H1N1, hepatitis C virus (HCV), and dengue virus. Here, we show that PF4 is an inhibitor of enterovirus A71 (EV71) and coxsackievirus A16 (CA16) infections. The secreted form of PF4 from transfected cells or soluble purified PF4 from Escherichia coli, even lacking signal peptide affected secretion, obviously inhibited the propagation of EV71 and CA16. Mechanistically, we demonstrated that PF4 blocked the entry of the virus into the host cells by interactions with VP3 proteins of EV71/CA16 and the interaction with SCARB2 receptor-mediated EV71 and CA16 endocytosis. As expected, the incubation of anti-PF4 antibody with PF4 blocked PF4 inhibition on EV71 and CA16 infections further supported the above conclusion. Importantly, pretreatment of EV71 viruses with PF4 significantly protected the neonatal mice from EV71 lethal challenge and promoted the survival rate of infected mice. PF4 derived from natural platelets by EV71/CA16 activation also presented strong inhibition on EV71 and CA16. In summary, our study identified a new host factor against EV71 and CA16 infections, providing a novel strategy for EV71 and CA16 treatment. IMPORTANCE The virus's life cycle starts with binding to cell surface receptors, resulting in receptor-mediated endocytosis. Targeting the entry of the virus into target cells is an effective strategy to develop a novel drug. EV71 and CA16 are the major pathogens that cause hand, foot, and mouth disease (HFMD) outbreaks worldwide since 2008. However, the treatment of EV71 and CA16 infections is mainly symptomatic because there is no approved drug. Therefore, the underlying pathogenesis of EV71/CA16 and the interaction between host-EV71/CA16 need to be further investigated to develop an inhibitor. Here, we identified PF4 as a potent entry inhibitor of EV71 and CA16 via binding to VP3 proteins of EV71 and CA16 or binding to receptor SCARB2. In the EV71 infection model, PF4 protected mice from EV71 lethal challenge and promoted the survival rate of EV71-infected mice. Our study suggests that PF4 represents a potential candidate host factor for anti-EV71 and CA16 infections.

The association between platelet-lymphocyte ratio and the risk of all-cause mortality in chronic kidney disease: a systematic review and meta-analysis

BACKGROUND

Chronic kidney disease (CKD) patients have high levels of inflammatory mediators. These inflammatory mediators contribute to the increased risk of cardiovascular events and all-cause mortality. Platelet-lymphocyte ratio (PLR) has recently been recognized as a novel inflammatory marker and has been shown to be associated with the prognosis in CKD patients. However, the quality of these studies varies and their results are controversial. The purpose of this meta-analysis was to investigate the relationship between PLR and all-cause mortality in CKD patients.

METHODS

A systematic literature search of PubMed, EMBASE, CENTRAL and ISI Web of Science was conducted. The databases were searched from their inception dates up to the latest issue (31 October 2021). Two reviewers independently searched the databases and screened studies. Data were extracted using a standardized collection form. Meta-analysis was performed to compare PLR values between CKD and non-CKD patients, and to investigate the association between PLR and all-cause mortality in CKD patients. This meta-analysis is reported in adherence to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA).

RESULTS

A total of 11 studies involving 4244 participants were selected. The pooled data indicated that PLR values were significantly higher in CKD patients than non-CKD controls (weighted mean difference = 21.6, 95% CI 17.39-25.81, p < 0.01), and PLR is associated with an increased risk of all-cause mortality in CKD patients (hazard ratio = 2.49, 95% CI 1.78-3.49, p < 0.01).

CONCLUSIONS

Patients with CKD have higher PLR values compared to non-CKD patients. Meanwhile, PLR values were highly associated with all-cause mortality in CKD patients. PLR is a valid predictor as a clinically accessible indicator for patients with CKD.

Prognostic significance of platelet-to-lymphocyte and platelet-to-neutrophil ratios in patients with mechanical thrombectomy for acute ischemic stroke

Objective

The present study aimed to analyze the correlation between platelet-to-lymphocyte ratio (PLR) and platelet-to-neutrophil ratio (PNR) with prognosis of patients who underwent mechanical thrombectomy (MT).

Methods

A total of 432 patients was included, PLR and PNR were calculated from laboratory data on admission. Prognosis was evaluated with a modified Rankin Scale at 3 months after MT. Using receiver operating characteristic (ROC) analysis, optimal cutoff values of PLR and PNR were identified to predict the prognosis after MT. Multivariate analyses were performed to identify the relationship of PLR and PLR with prognosis of MT.

Results

Patients with favorable outcomes had a lower mean PLR (135.0, standard deviation [SD] 120.3) with a higher mean PNR (47.1 [SD] 24.6) compared with patients with unfavorable outcomes (167.6 [SD] 139.3 and 35.4 [SD] 22.4) (p<0.001 and <0.001, respectively). In ROC analyses, the optimal cutoff value of PLR and PNR to predict the 3 months prognosis were 145 and 41, respectively (p=<0.001 and p=0.006). In multivariate analysis, PLR less than 145 (odds ratio [OR] 1.29, 95% confidence interval [CI] 1.06–2.06; p=0.016) and PNR greater than 41 (OR 1.22, 95% CI 1.10–1.62; p=0.022) were predictors of favorable outcome at 3 months.

Conclusions

In patients with MT, PLR and PNR on admission could be predictive factors of prognosis and mortality at 3 months. Decreased PLR and increased PNR were associated with favorable clinical outcome 3 months after MT.

Treatment of Androgenetic Alopecia Using PRP to Target Dysregulated Mechanisms and Pathways

Androgenetic alopecia (“AGA”) is the most prevalent type of progressive hair loss, causing tremendous psychological and social stress in patients. However, AGA treatment remains limited in scope. The pathogenesis of androgenetic alopecia is not completely understood but is known to involve a hair follicle miniaturization process in which terminal hair is transformed into thinner, softer vellus-like hair. This process is related to the dysregulation of the Wnt/β-catenin signaling pathway, which causes premature termination of the anagen growth phase in hair follicles. Historically used for wound healing, platelet rich plasma (“PRP”) has recently been at the forefront of potential AGA treatment. PRP is an autologous preparation of plasma that contains a high number of platelets and their associated growth factors such as EGF, IGF-1, and VEGF. These factors are known to individually play important roles in regulating hair follicle growth. However, the clinical effectiveness of PRP is often difficult to characterize and summarize as there are wide variabilities in the PRP preparation and administration protocols with no consensus on which protocol provides the best results. This study follows the previous review from our group in 2018 by Cervantes et al. to analyze and discuss recent clinical trials using PRP for the treatment of AGA. In contrast to our previous publication, we include recent clinical trials that assessed PRP in combination or in direct comparison with standard of care procedures for AGA such as topical minoxidil and/or oral finasteride. Overall, this study aims to provide an in-depth analysis of PRP in the treatment of AGA based on the evaluation of 17 recent clinical trials published between 2018 and October 2021. By closely examining the methodologies of each clinical trial included in our study, we additionally aim to provide an overall consensus on how PRP can be best utilized for the treatment of AGA.

Platelets, a Key Cell in Inflammation and Atherosclerosis Progression

Platelets play important roles in thrombosis-dependent obstructive cardiovascular diseases. In addition, it has now become evident that platelets also participate in the earliest stages of atherosclerosis, including the genesis of the atherosclerotic lesion. Moreover, while the link between platelet activity and hemostasis has been well established, the role of platelets as modulators of inflammation has only recently been recognized. Thus, through their secretory activities, platelets can chemically attract a diverse repertoire of cells to inflammatory foci. Although monocytes and lymphocytes act as key cells in the progression of an inflammatory event and play a central role in plaque formation and progression, there is also evidence that platelets can traverse the endothelium, and therefore be a direct mediator in the progression of atherosclerotic plaque. This review provides an overview of platelet interactions and regulation in atherosclerosis.

Investigation of Platelet Aggregation in Atherosclerosis

Platelet activation and aggregation is implicated in all stages of inflammation-related atherosclerosis from the initial steps of endothelial dysfunction and plaque formation, to plaque rupture and atherothrombotic events, such as acute coronary syndrome, myocardial infarction, and ischemic incidences. Platelet aggregometry assays are the mainstream for evaluating and monitoring platelet reactivity in such conditions and for the investigation of prophylactic and therapeutic approaches. The most established methodology is light transmittance aggregometry (LTA). Here we describe the appropriate preparation of platelet suspensions from human blood and the methodology of LTA-based assays that is used for basic and clinical research for monitoring and evaluating the activities of several thrombotic mediators, as well as determining the dose efficacy and safety of several pharmaceutical and nutraceutical compounds intended for therapeutic and prophylactic interventions for atherosclerosis.

Adipose Triglyceride Lipase Deficiency Attenuates In Vitro Thrombus Formation without Affecting Platelet Activation and Bleeding In Vivo

According to genome-wide RNA sequencing data from human and mouse platelets, adipose triglyceride lipase (ATGL), the main lipase catalyzing triglyceride (TG) hydrolysis in cytosolic lipid droplets (LD) at neutral pH, is expressed in platelets. Currently, it is elusive to whether common lipolytic enzymes are involved in the degradation of TG in platelets. Since the consequences of ATGL deficiency in platelets are unknown, we used whole-body and platelet-specific (plat)Atgl-deficient (-/-) mice to investigate the loss of ATGL on platelet function. Our results showed that platelets accumulate only a few LD due to lack of ATGL. Stimulation with platelet-activating agonists resulted in comparable platelet activation in Atgl-/-, platAtgl-/-, and wild-type mice. Measurement of mitochondrial respiration revealed a decreased oxygen consumption rate in platelets from Atgl-/- but not from platAtgl-/- mice. Of note, global loss of ATGL was associated with an anti-thrombogenic phenotype, which was evident by reduced thrombus formation in collagen-coated channels in vitro despite unchanged bleeding and occlusion times in vivo. We conclude that genetic deletion of ATGL affects collagen-induced thrombosis without pathological bleeding and platelet activation.

Engineered platelets-based drug delivery platform for targeted thrombolysis

Thrombolytic agents have thus far yielded limited therapeutic benefits in the treatment of thrombotic disease due to their short half-life, low targeting ability, and association with serious adverse reactions, such as bleeding complications. Inspired by the natural roles of platelets during thrombus formation, we fabricated a platelet-based delivery system (NO@uPA/PLTs) comprising urokinase (uPA) and arginine (Arg) for targeted thrombolysis and inhibition of re-embolism. The anchoring of uPA to the platelet surface by lipid insertion increased the thrombotic targeting and in vivo circulation duration of uPA without disturbing platelet functions. Nitric oxide (NO) generated by the loaded Arg inhibited platelet aggregation and activation at the damaged blood vessel, thereby inhibiting re-embolism. NO@uPA/PLTs effectively accumulated at the thrombi in pulmonary embolism and carotid artery thrombosis model mice and exerted superior thrombolytic efficacy. In addition, the platelet delivery system showed excellent thrombus recurrence prevention ability in a mouse model of secondary carotid artery injury. The coagulation indicators in vivo showed that the platelet-based uPA and NO co-delivery system possessed a low hemorrhagic risk, providing a promising tool for rapid thrombolysis and efficient inhibition of posttreatment re-embolism.

MEAN PLATELET VOLUME PREDICTS RESTENOSIS AFTER CAROTID ENDARTERECTOMY

BACKGROUND

Carotid restenosis following carotid endarterectomy (CEA) has a cumulative risk at 5-years up to 32%, which may impact the well-being of patients following CEA. Haematological parameters in the standard complete blood cell count (CBC) are emerging as potential biomarkers, but their application in CEA is scarce. The primary aim of this study was to investigate haematological markers for restenosis following CEA. The secondary aim was to characterize clinical risk factors for restenosis.

METHODS

From January 2012 to January 2019, 151 patients who underwent CEA under regional anaesthesia due to carotid stenosis were selected from a prospectively maintained cohort database. Patients were included if a preoperative CBC was available in the two weeks preceding CEA. Multivariable analysis was performed alongside propensity score matching (PSM) analysis, using the preoperative CEA parameters, to reduce confounding factors between categories.

RESULTS

The study group comprised 28 patients who developed carotid restenosis. The remaining 123 patients without restenosis composed the control group. Mean age of the patients did not differ significantly between groups (70.25±8.05 vs. 70.32 ± 9.61 YO, p=0.973), neither did gender (male gender 89.3% vs. 78.9%, p=0.206). Regarding haematological parameters, only MPV remained statistically significant within multivariable analysis (1.855, aOR [1.174-2.931], p=0.008), a result supported by PSM analysis (2.072, aOR [1.036-4.147], p=0.042).

CONCLUSION

MPV was able to predict restenosis two years after CEA. Thus, MPV can be incorporated into score calculations to identify patients at greater risk of restenosis, who could benefit from specific monitoring during follow-up. While results are promising, more research is necessary to corroborate them.

Neutrophil-to-Lymphocyte Ratio and Erythropoietin Resistance among Maintenance Hemodialysis Patients

INTRODUCTION

Neutrophil lymphocyte ratio (NLR) and platelet lymphocyte ratio (PLR) are recent prognostic biomarkers associated with inflammation. Increased erythropoiesis resistance index (ERI) may predict the risk of all-cause and cardiovascular mortality in hemodialysis (HD) patients. However, the roles of NLR and PLR in erythropoietin (EPO) responsiveness remain unclear in HD patients. This study aims to investigate the relationship between NLR and PLR and EPO responsiveness in maintenance HD patients.

METHODS

A total of 299 HD patients were included in this survey. Laboratory data and demographic details were collected. EPO responsiveness was evaluated by ERI. Pearson correlation analysis and logistic regressions were conducted to evaluate the factors that may be associated with EPO responsiveness.

RESULTS

The EPO responsiveness was positively related to ferritin and negatively related to serum albumin, lymphocytes, and hemoglobin. A multivariate linear regression revealed that only NLR (standardized β = 0.13, p = 0.024) but not PLR (standardized β = 0.107, p = 0.063) was correlated with a higher ERI.

CONCLUSION

A higher NLR level was shown to be a cheaper method to predict worse EPO responsiveness in HD patients.

Antithrombogenic properties of Tulbaghia violacea aqueous leaf extracts: assessment of platelet activation and whole blood clotting kinetics

Tulbaghia violacea plant extracts have been investigated for their potential therapeutic effects in the management of various ailments, among which are cardiovascular diseases, due to the wide range of phytocompounds that the plant possesses. One of the major challenges in clinical practice is the inability to control platelet activation and clotting caused by cardiovascular disease interventions. Current treatment methods to inhibit platelet aggregation and thromboxane formation have been associated with major undesirable side effects. This has led to increased research studies on the development of newer and more effective antiplatelet agents. In particular, there has been a growing interest on the potential antiplatelet activity of plant-derived extracts. Hence this study methodically evaluates the anticlotting and antiplatelet properties of T. violacea aqueous leaf extracts. The platelet activity of the plant extracts was assessed using total platelet adhesion, platelet morphology and whole blood clotting kinetics. The 0.1 mg ml⁻¹T. violacea extract mixed with blood plasma demonstrated the lowest platelet adhesion and activation and also reduced whole blood clotting kinetics. There was a reduction of about 70% in platelet adhesion for the 0.1 mg ml⁻¹ treatment compared to the control in the first 15 min which was supported by morphological characterization under SEM. These observations suggest that T. violacea may be a potential antiplatelet therapeutic agent to inhibit the initial step of platelet adhesion and ultimately reduce the incidence of cardiovascular events.

Tulbaghia violacea plant extracts have been investigated for their potential therapeutic effects in the management of various ailments, among which are cardiovascular diseases, due to the wide range of phytocompounds that the plant possesses.

Clustering of blood cell count abnormalities and future risk of death

BACKGROUND

The identification of novel predictors of poor outcome may help stratify cardiovascular risk. Aim was to evaluate the individual contribution of blood cell count parameters, as well as their clustering, on the risk of death and cardiovascular events over the long term in the population-based Malmö Diet and Cancer Study cohort.

METHODS

In 30,447 individuals (age 57 ± 8 years), we assessed the incidence of all-cause death (primary endpoint) and major adverse cardiovascular events (MACE, secondary outcome measure) according to absence or presence of one, two and three factors at baseline out of the following: anaemia, leukocytosis and thrombocytosis. Median follow-up was 16 years.

RESULTS

The percentages of all-cause death were 19.5% in individuals without factors, 21.3% in those with one factor, 27.4% with two and 46.4% with three (log-rank test P < .001). The crude incidence of MACE was 28.0%, 29.2%, 35.5% and 57.1%, respectively (log-rank test P < .001). At multivariate analysis, we found a stepwise increase in overall mortality with increasing number of prevalent factors (one factor: HR 1.23, 95% CI 1.14-1.31, P < .001; two factors: 1.61, 1.37-1.89, P < .001; three factors: 2.69, 1.44-5.01, P = .002, vs no factor). Similar findings were observed for the incidence of MACE (one factor: adjusted HR 1.18, 95% CI 1.11-1.24, P < .001; two factors: 1.52, 1.33-1.76, P < .001; three factors: 2.03, 1.21-3.67, P < .001, vs no factor).

CONCLUSIONS

The easily assessable clustering of anaemia, leukocytosis and thrombocytosis heralds higher incidence of death and adverse cardiovascular events.

Studying dynamic stress effects on the behaviour of THP-1 cells by microfluidic channels

Atherosclerosis is a long-term disease process of the vascular system that is characterized by the formation of atherosclerotic plaques, which are inflammatory regions on medium and large-sized arteries. There are many factors contributing to plaque formation, such as changes in shear stress levels, rupture of endothelial cells, accumulation of lipids, and recruitment of leukocytes. Shear stress is one of the main factors that regulates the homeostasis of the circulatory system; therefore, sudden and chronic changes in shear stress may cause severe pathological conditions. In this study, microfluidic channels with cavitations were designed to mimic the shape of the atherosclerotic blood vessel, where the shear stress and pressure difference depend on design of the microchannels. Changes in the inflammatory-related molecules ICAM-1 and IL-8 were investigated in THP-1 cells in response to applied shear stresses in an continuous cycling system through microfluidic channels with periodic cavitations. ICAM-1 mRNA expression and IL-8 release were analyzed by qRT-PCR and ELISA, respectively. Additionally, the adhesion behavior of sheared THP-1 cells to endothelial cells was examined by fluorescence microscopy. The results showed that 15 Pa shear stress significantly increases expression of ICAM-1 gene and IL-8 release in THP-1 cells, whereas it decreases the adhesion between THP-1 cells and endothelial cells.

Evaluation of the effects of nanoparticles on the therapeutic function of platelet: a review

OBJECTIVES

Nanotechnology and nanoparticles are used in different applications in disease monitoring and therapy in contact with blood. Nanoparticles showed different effects on blood components and reduced or improved the function of therapeutic platelet during the storage time. This review study was performed to evaluate the impacts of various sizes and charges of nanoparticles on platelet function and storage time. The present review contains the literature between 2010 and 2020. The data have been used from different sites such as PubMed, Wiley, ScienceDirect and online electronic journals.

KEY FINDINGS

From the literature survey, it has been demonstrated that among various properties, size and charge of nanoparticles were critical on the function of therapeutic platelet during the storage and inhibition of their aggregation. Overall, this study described that nanoparticles with smaller size and negative charge were more effective in increasing the survival time, inhibition of aggregation and improving the function of therapeutic platelet.

SUMMARY

Based on the current review, it can be confirmed that nanoparticles such as dendrimer, Au, Ag and iron oxide nanoparticles with smaller size and negative charge have significant advantages for improving the efficacy of platelets during the storage chain and inhibition of their aggregation.

The Role of the Proteasome in Platelet Function

Platelets are megakaryocyte-derived acellular fragments prepped to maintain primary hemostasis and thrombosis by preserving vascular integrity. Although they lack nuclei, platelets harbor functional genomic mediators that bolster platelet activity in a signal-specific manner by performing limited de novo protein synthesis. Furthermore, despite their limited protein synthesis, platelets are equipped with multiple protein degradation mechanisms, such as the proteasome. In nucleated cells, the functions of the proteasome are well established and primarily include proteostasis among a myriad of other signaling processes. However, the role of proteasome-mediated protein degradation in platelets remains elusive. In this review article, we recapitulate the developing literature on the functions of the proteasome in platelets, discussing its emerging regulatory role in platelet viability and function and highlighting how its functional coupling with the transcription factor NF-κB constitutes a novel potential therapeutic target in atherothrombotic diseases.

EVALUATION OF THE RELATIONSHIP OF MPV, RDW AND PVI PARAMETERS WITH DISEASE SEVERITY IN COVID-19 PATIENTS

Coronavirus was first detected in three severe pneumonia cases in Wuhan, China, in December 2019. Studies on red cell distribution width (RDW-CV) and mean platelet volume (MPV) laboratory parameters, which can be examined in complete blood count in COVID-19 patients, are still very limited. However, to the best of our knowledge, there are no studies examining the relationship between platelet volume index (PVI) and disease severity in COVID-19 patients, which was evaluated in this study. The aim of this study was to evaluate the relationship of disease severity in COVID-19 patients with their MPV, RDW, and PVI parameters. The study included 92 COVID-19 patients as a study group and 84 healthy individuals as control group. All laboratory data and radiological images were scanned retrospectively from patient files and hospital information system. Evaluation of the RDW-CV and MPV blood parameters, and PVI measured in COVID-19 patients yielded statistically significant differences according to the disease severity. We suggest that RDW-CV and PVI, evaluated within the scope of the study, may be the parameters that should be considered in the early diagnosis of the disease, from the initial stages of COVID-19. In addition, we think that the RDW-CV and MPV laboratory parameters, as well as PVI, which all are simple, inexpensive and widely used hematologic tests, can be used as important biomarkers in determining COVID-19 severity and mortality.

Role of neutrophil-to-lymphocyte and platelet-to-lymphocyte ratios in Peyronie's disease: a new diagnostic approach to predict the stage of the disease?

Neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) have been associated with multiple entities and several types of cancers. They can be assumed as markers of inflammatory imbalance. The objective of this study is to evaluate the NLR and PLR in Peyronie's disease (PD) and to establish a comparison of its values in the acute and chronic stages. We recruited patients with PD from March 2018 to March 2019. The patients enrolled underwent medical and sexual history as well as a physical examination. The values of blood count of each patient were collected both in the acute and chronic stages. Wilcoxon test was used to compare the acute and chronic stage ratios. Kruskal–Wallis test was carried out to evaluate the impact of treatments on the ratios. To identify cutoff values, we used sensibility and specificity tables and receiver operating characteristic (ROC) curves. A total of 120 patients were enrolled. Their mean age was 55.85 (range: 18–77) years and the mean penile curvature was 48.43° (range: 10°–100°). In the acute stage, the mean NLR was 2.35 and the mean PLR was 111.22. These ratios, in the chronic stage, were 1.57 and 100.00, respectively. Statistically significant differences between acute and stable stages for both indices were found (NLR: P < 0.0001; PLR: P = 0.0202). The optimal cutoff for classification in acute or stable stage was 2 for NLR and 102 for PLR. According to our results, with an ordinary blood count, we could have important indications regarding the disease stage of the patient, and consequently on the most appropriate type of therapy to choose.

Clinical hematological and biochemical parameters in Swiss, BALB/c, C57BL/6 and B6D2F1 Mus musculus

BACKGROUND

Animal models are widely used in scientific research in order to obtain information from a whole organism under a specific set of experimental conditions. Various lineages of mice have been used to investigate diseases and new therapeutic strategies, and, consequently, hematological and biochemical tests in these laboratory animals are essential to validate scientific studies. Our study seeks to establish reference values for hematological and biochemical parameters of four lineages of mice.

METHODS

We evaluated the hematological and biochemical profiles of 20 males and 20 females from the lineages Swiss (heterogeneous), BALB/c and C57BL/6 (isogenic), and B6D2F1 (hybrid), totaling 160 mice. Analysis were standardized using the systems pocH-100iV Diff™ for 19 hematological parameters and VITROS® 350 for 12 biochemical parameters.

RESULTS

Results are shown as means and standard deviation, grouped by lineage and genre. Comparing the values obtained in this study with the values from previous studies, some variations were detected, which could be explained by differences in methodologies or individual variability.

CONCLUSION

Thus our study shows that knowledge and disclosure of the values of physiological parameters of laboratory animals is necessary, and emphasises the importance of considering variations influenced by gender, lineage and genotype in the choice of the best experimental model.

Acute platelet response to aneurysmal subarachnoid hemorrhage depends on severity and distribution of bleeding: an observational cohort study

Microthrombosis after aneurysmal subarachnoid hemorrhage (aSAH) is considered to initiate neuroinflammation, vessel remodeling, and blood-brain barrier leakage. We aimed to verify the hypothesis that the intensity of thrombogenicity immediately after aSAH depends on the amount and distribution of extravasated blood. This observational cohort study included 37 consecutive aSAH patients admitted no longer than 24 h after ictus. Volumes of subarachnoid and intraventricular hemorrhages as well as the Subarachnoid Hemorrhage Early Brain Edema Scale (SEBES) score were calculated in each case. Platelet system status was described by platelet count (PLT), mean platelet volume (MPV), MPV to PLT ratio, and platelet-large cell ratio (P-LCR). Median hemorrhage volume amounted to 11.4 ml (interquartile range 2.8-26.8 ml). Patients with more severe hemorrhage had lower PLT and higher MPV to PLT ratio (ρ =  - 0.49, p < .002; ρ = 0.50, p < .002, respectively). PLT decreased by 2.80 G/l per 1 ml of hemorrhage volume (95% CL 1.30-4.30, p < .001). Further analysis revealed that intraventricular hemorrhage volume was associated with P-LCR and MPV (ρ = 0.34, p < .039; ρ = 0.33, p < .048, respectively), whereas SAH volume with PLT and MPV:PLT ratio (ρ =  - 0.40, p < .013; ρ = 0.41, p < .013, respectively). The odds of unfavorable neurological outcome increased 3.95 times per 1 fl of MPV (95% CI 1.19-13.12, p < .025). MPV was independently correlated with SEBES (ρ = 0.44, p < .006). This study demonstrated that the extent and distribution of aneurysmal subarachnoid hemorrhage are related to different types of acute platelet response, which may be interpreted as local and systemic thrombogenicity. Increased mean platelet volume measured in the acute phase of aSAH may identify patients at risk for unfavorable neurological outcomes and may serve as a marker of early brain injury.

Relationship between the first pass effect and the platelet-lymphocyte ratio in acute ischemic stroke

PURPOSE

The aim of this study was to evaluate the relationship between platelet-lymphocyte ratio (PLR) and first pass effect (FPE) in patients with acute ischemic stroke (AIS). Our secondary goal was to investigate other laboratory, demographic or technical parameters that may be related to FPE and to search for independent predictors of FPE.

MATERIALS AND METHODS

Patients who underwent mechanical thrombectomy (MT) in our hospital between January 2017 and February 2020 were reviewed. Patients were divided into two groups: FPE and non-FPE. Demographic features, laboratory parameters, pretreatment imaging and clinical features, angiographic and clinical outcomes were recorded and compared between the two groups. Logistic regression analysis was performed to analyze the independent predictors and a predictive model was produced for demonstrating the possibility to achieve FPE.

RESULTS

The study consisted of 83 patients (37 female, 46 male; mean age 62.69 ± 15.16) who were treated by MT. FPE was achieved in 32 patients (32/83, 38.6%). PLR was higher in the non-FPE group (195.35 ± 101.49) when compared to the FPE group (103.17 ± 37.06). A PLR value of <126.3 and female sex were found as independent predictors of FPE. Our predictive model estimated the chance of FPE as 77.9% in female patients who had PLR values lower than 126.3 while it was 77.1% when only using the PLR cutoff value.

CONCLUSIONS

High levels of PLR were associated with the failure of FPE. High values of PLR may be considered as a negative predictor for FPE achievement prior to MT in patients with AIS.

Role of Platelet Cytokines in Dengue Virus Infection

Platelets are anucleated blood cells derived from bone marrow megakaryocytes and play a crucial role in hemostasis and thrombosis. Platelets contain specialized storage organelles, called alpha-granules, contents of which are rich in cytokines such as C-X-C Motif Chemokine Ligand (CXCL) 1/4/7, (C-C motif) ligand (CCL) 5/3, CXCL8 (also called as interleukin 8, IL-8), and transforming growth factor β (TGF-β). Activation of platelets lead to degranulation and release of contents into the plasma. Platelet activation is a common event in many viral infections including human immunodeficiency virus (HIV), H1N1 influenza, Hepatitis C virus (HCV), Ebola virus (EBV), and Dengue virus (DENV). The cytokines CXCL8, CCL5 (also known as Regulated on Activation, Normal T Expressed and Secreted, RANTES), tumor necrosis factor α (TNF-α), CXCL1/5 and CCL3 released, promote development of a pro-inflammatory state along with the recruitment of other immune cells to the site of infection. Platelets also interact with Monocytes and Neutrophils and facilitate their activation to release different cytokines which further enhances inflammation. Upon activation, platelets also secrete factors such as CXCL4 (also known as platelet factor, PF4), CCL5 and fibrinopeptides which are critical regulators of replication and propagation of several viruses in the host. Studies suggest that CXCL4 can both inhibit as well as enhance HIV1 infection. Data from our lab show that CXCL4 inhibits interferon (IFN) pathway and promotes DENV replication in monocytes in vitro and in patients significantly. Inhibition of CXCL4 mediated signaling results in increased IFN production and suppressed DENV and JEV replication in monocytes. In this review, we discuss the role of platelets in viral disease progression with a focus on dengue infection.

Extracellular Vesicle-Related Thrombosis in Viral Infection

Although the outcomes of viral infectious diseases are remarkably varied, most infections cause acute diseases after a short period. Novel coronavirus disease 2019, which recently spread worldwide, is no exception. Extracellular vesicles (EVs) are small circulating membrane-enclosed entities shed from the cell surface in response to cell activation or apoptosis. EVs transport various kinds of bioactive molecules between cells, including functional RNAs, such as viral RNAs and proteins. Therefore, when EVs are at high levels, changes in cell activation, inflammation, angioplasty and transportation suggest that EVs are associated with various diseases. Clinical research on EVs includes studies on the coagulatory system. In particular, abnormal enhancement of the coagulatory system through EVs can cause thrombosis. In this review, we address the functions of EVs, thrombosis, and their involvement in viral infection.

Adenosine Receptor Agonists Increase the Inhibition of Platelet Function by P2Y12 Antagonists in a cAMP- and Calcium-Dependent Manner

We have shown previously that platelet activity can be lowered through the simultaneous inhibition of P2Y₁₂ receptor and activation of adenosine receptors (AR). This work explores this concept by testing the antiplatelet potential of nine AR agonists in combination with P2Y₁₂ receptor antagonists—cangrelor and prasugrel metabolite. A panel of in vitro methods was used to assess platelet viability, P-selectin expression, GPIIb-IIIa activation, fibrinogen binding, calcium ion mobilization, VASP-P level, and cAMP formation, utilizing whole blood or isolated platelets from healthy volunteers. The AR agonists demonstrated anti-platelet effects, but stimulated signaling pathways to varying degrees. AR agonists and P2Y₁₂ antagonists reduced expression of both P-selectin and the activated form of GPIIb-IIIa on platelets; however, the combined systems (AR agonist + P2Y₁₂ antagonist) demonstrated stronger effects. The antiplatelet effects of AR when combined with P2Y₁₂ were more pronounced with regard to exogenous fibrinogen binding and calcium mobilization. The cAMP levels in both resting and ADPactivated platelets were increased by AR agonist treatment, and more so when combined with P2Y₁₂ inhibitor. In conclusion, as AR agonists are fast-acting compounds, the methods detecting early activation events are more suitable for assessing their antiplatelet action. The exogenous fibrinogen binding, calcium mobilisation and cAMP level turned out to be sensitive markers for detecting the inhibition caused by AR agonists alone or in combination with P2Y₁₂ receptor antagonists.

Biomechanical thrombosis: the dark side of force and dawn of mechano-medicine

Arterial thrombosis is in part contributed by excessive platelet aggregation, which can lead to blood clotting and subsequent heart attack and stroke. Platelets are sensitive to the haemodynamic environment. Rapid haemodynamcis and disturbed blood flow, which occur in vessels with growing thrombi and atherosclerotic plaques or is caused by medical device implantation and intervention, promotes platelet aggregation and thrombus formation. In such situations, conventional antiplatelet drugs often have suboptimal efficacy and a serious side effect of excessive bleeding. Investigating the mechanisms of platelet biomechanical activation provides insights distinct from the classic views of agonist-stimulated platelet thrombus formation. In this work, we review the recent discoveries underlying haemodynamic force-reinforced platelet binding and mechanosensing primarily mediated by three platelet receptors: glycoprotein Ib (GPIb), glycoprotein IIb/IIIa (GPIIb/IIIa) and glycoprotein VI (GPVI), and their implications for development of antithrombotic 'mechano-medicine' .

Combined prognostic significance of D-dimer level and platelet count in acute ischemic stroke

BACKGROUND

D-dimer level and platelet count (PC) have been reported separately as significant independent predictors of Acute Ischemic Stroke (AIS). Here, we aimed to investigate the combined prognostic value of abnormal D-dimer level and PC as defined for specific in-hospital and long-term outcomes in AIS patients.

METHODS

A total of 1468 patients admitted for ischemic stroke within 24 h of symptom onset from April 1, 2016 to November 31, 2019 at the Department of Neurology, the First Affiliated Hospital of Harbin Medical University were included in the final analysis. Eligible subjects were divided into four groups in terms of their levels of D-dimer and PC: DD-PC- (normal D-dimer level and normal PC), DD-PC+ (normal D-dimer level and abnormal PC), DD+PC- (higher D-dimer level and normal PC), and DD+PC+ (higher D-dimer level and abnormal PC). Logistic regression model and multinomial logit model were used to estimate the combined effect of D-dimer level and PC on in-hospital outcomes including discharge outcome and early neurological changes, and poor outcomes at 3, 6 and 12 months.

RESULTS

DD+PC+ was found to be associated with the risk of in-hospital mortality (adjusted odds ratio [OR], 6.904; 95% confidence interval [CI], 2.781-17.144) and 3-month mortality (adjusted OR, 5.455; 95% CI, 2.019-14.743) compared with DD-PC-. Combination of the two indicators significantly improved the independent predictive value for functional outcomes, including early neurological deterioration (END) (OR, 3.622; 95% CI, 1.732-7.573) with threshold of at least 4-point increase on NIHSS, discharge outcome (OR, 2.713; 95% CI, 1.421-5.177); mRS of 0-1 point (OR, 0.409; 95% CI, 0.211-0.792), mRS of 0-2 points (OR, 0.234; 95% CI, 0.118, 0.461), and higher mRS-shift (OR, 2.379; 95% CI, 1.237-4.576) at 3 months; unfavorable outcome at 3 months (OR, 4.280; 95% CI, 2.169-8.446), 6 months (OR, 3.297; 95% CI, 1.452-7.488) and 12 months (OR, 4.157; 95% CI, 1.598-10.816). While comparatively weaker statistical significance was shown in DD+PC- and no correlation was found between adverse outcomes and DD-PC+. Similarly, patients with abnormal D-dimer level and PC were less likely to reach the status of stable or improving.

CONCLUSIONS

Combination of D-dimer level and PC may have more significant prognostic value on END, in-hospital mortality, discharge outcome, and long-term outcomes than either index of D-dimer level or PC alone in AIS patients.