Platelet disorders: an overview

Impact of administration routes and dose frequency on the toxicology of SARS-CoV-2 mRNA vaccines in mice model

The increasing use of SARS-CoV-2 mRNA vaccines has raised concerns about their potential toxicological effects, necessitating further investigation to ensure their safety. To address this issue, we aimed to evaluate the toxicological effects of SARS-CoV-2 mRNA vaccine candidates formulated with four different types of lipid nanoparticles in ICR mice, focusing on repeated doses and administration routes. We conducted an extensive analysis in which mice received the mRNA vaccine candidates intramuscularly (50 μg/head) twice at 2-week intervals, followed by necropsy at 2 and 14 dpsi (days post-secondary injection). In addition, we performed a repeated dose toxicity test involving three, four, or five doses and compared the toxicological outcomes between intravenous and intramuscular routes. Our findings revealed that all vaccine candidates significantly induced SARS-CoV-2 spike protein-specific IgG and T cell responses. However, at 2 dpsi, there was a notable temporary decrease in lymphocyte and reticulocyte counts, anemia-related parameters, and significant increases in cardiac damage markers, troponin-I and NT-proBNP. Histopathological analysis revealed severe inflammation and necrosis at the injection site, decreased erythroid cells in bone marrow, cortical atrophy of the thymus, and increased spleen cellularity. While most toxicological changes observed at 2 dpsi had resolved by 14 dpsi, spleen enlargement and injection site damage persisted. Furthermore, repeated doses led to the accumulation of toxicity, and different administration routes resulted in distinct toxicological phenotypes. These findings highlight the potential toxicological risks associated with mRNA vaccines, emphasizing the necessity to carefully consider administration routes and dosage regimens in vaccine safety evaluations, particularly given the presence of bone marrow and immune organ toxicity, which, though eventually reversible, remains a serious concern.

A real-world disproportionality analysis of FDA adverse event reporting system (FAERS) events for avatrombopag

Avatrombopag is a next-generation thrombopoietin receptor agonist approved for the treatment of thrombocytopenia in patients with chronic liver disease scheduled to undergo surgery and thrombocytopenia in patients with chronic immune thrombocytopenia. However, realistic data on its post-marketing long-term safety and tolerability in large sample populations are incomplete. The adverse event (AE) reports of avatrombopag were analyzed based on the FAERS database. By extracting large-scale data from the FAERS database, this study used various signal quantification techniques such as reporting odds ratios, proportional reporting ratios, Bayesian confidence propagation neural network, and multi-item gamma Poisson shrinker to calculate and evaluate the ratio and association between avatrombopag and specific AEs. In the FAERS database, data from the second quarter of 2018 to the fourth quarter of 2023 were extracted for this study, a total of 1217 avatrombopag-related AEs reports were included for analysis. Based on four calculation methods, this study identified and 32 preferred terms associated with avatrombopag. Common AEs in the product label such as thrombosis, headache, contusion, petechiae, and gingival bleeding were detected. AEs not mentioned in the product label, such as photopsia and ear discomfort were also detected. The first 30 days after initiation of medication were the most common period for both serious and non-serious AEs. This study demonstrates the common AEs and the potential AEs associated with avatrombopag in real-world practice, which could provide valuable cautionary evidence for clinicians and pharmacists to manage safety issues with avatrombopag.

Nanoscale insights into hematology: super-resolved imaging on blood cell structure, function, and pathology

Fluorescence nanoscopy, also known as super-resolution microscopy, has transcended the conventional resolution barriers and enabled visualization of biological samples at nanometric resolutions. A series of super-resolution techniques have been developed and applied to investigate the molecular distribution, organization, and interactions in blood cells, as well as the underlying mechanisms of blood-cell-associated diseases. In this review, we provide an overview of various fluorescence nanoscopy technologies, outlining their current development stage and the challenges they are facing in terms of functionality and practicality. We specifically explore how these innovations have propelled forward the analysis of thrombocytes (platelets), erythrocytes (red blood cells) and leukocytes (white blood cells), shedding light on the nanoscale arrangement of subcellular components and molecular interactions. We spotlight novel biomarkers uncovered by fluorescence nanoscopy for disease diagnosis, such as thrombocytopathies, malignancies, and infectious diseases. Furthermore, we discuss the technological hurdles and chart out prospective avenues for future research directions. This review aims to underscore the significant contributions of fluorescence nanoscopy to the field of blood cell analysis and disease diagnosis, poised to revolutionize our approach to exploring, understanding, and managing disease at the molecular level.

Reevaluating Thrombocytosis as a Risk Factor in Free Flap Surgery: Does Timing Matter?

INTRODUCTION

Thrombocytosis, defined as a platelet count >400,000, has been implicated as a risk factor in free flap failure. Despite proposed mechanisms of pedicle thrombosis, recent studies have suggested that thrombocytosis has no effect on free tissue transfer viability. Risk factors that may compromise successful free tissue transfer should be understood and elucidated, with particular attention to thrombocytosis and its conflicting evidence in the literature. We hypothesize that thrombocytosis has no bearing on free flap success or the rates of pedicle thrombosis.

METHODS

Our institution performed a retrospective chart review on all patients who underwent free flap reconstruction over the past 6 years. Patient demographics, medical history, type and location of free tissue transfer, preoperative platelets, postoperative platelets, and flap outcomes and complications (wound dehiscence, infection, hematoma, seroma, and need for blood transfusion) were recorded. Independent t test, Mann-Whitney U tests, χ2 test, and Fisher exact tests were used to determine P values to compare flap outcomes in patients with thrombocytosis (platelet count >400,000) and those with platelet counts less than 400,000.

RESULTS

In our 502-patient cohort, 71 were found to have a platelet count >400,000 (35 preoperatively and 36 postoperatively) and 431 patients had platelet counts <400,000. There were 42 reconstructive failures (flap success rate of 91.6%) and 111 returns to the operating room (OR). For patients with postoperative thrombocytosis, 24 flaps returned to the OR (44.4%), whereas in patients without thrombocytosis, 87 flaps returned to the OR (19.4%; P < 0.001). In patients with postoperative thrombocytosis, 10 OR returns were due to pedicle venous thrombosis (18.5%), in comparison to 10 returns for venous thrombosis in those with normal platelets (2.2%; P < 0.001). There was a small difference in free flap success rates between those with postoperative thrombocytosis and normal platelets, 88.7% versus 92.11%; however, this was not statistically significant ( P = 0.71). The thrombocytosis group had a higher incidence of overall postoperative complications ( P = 0.002).

CONCLUSIONS

Thrombocytosis has historically been cited as a risk factor for free flap reconstruction failure with recent conflicting evidence in the literature. In patients with postoperative thrombocytosis, we found an increased risk of venous thrombosis; however, this did not result in increased flap failure. There was an increase in postoperative complications, which corresponds with National Surgical Quality Improvement Program data reported in the literature. We suspect that thrombocytosis is not a harbinger of free flap failure but rather a marker for overall inflammation, which may confer a higher rate of venous thrombosis requiring reoperation and postoperative complications.

Influence of Spin Coating and Dip Coating with Gelatin/Hydroxyapatite for Bioresorbable Mg Alloy Orthopedic Implants: In Vitro and In Vivo Studies

Suitable biomechanical properties, good biocompatibility, and osteoconductivity of a degradable magnesium (Mg) alloy make it a potential material for orthopedic implants. The main limitation of Mg is its high corrosion rate in the human body. Surface modification is necessary to improve the Mg corrosion resistance. In this work, a polymeric layer of gelatin/nanohydroxyapatite (Gel/nHA) was coated on a ZK60 Mg alloy by dip coating and spin coating to test the corrosion resistance and biocompatibility in vitro and in vivo. The results from the in vitro test revealed that the coated groups reduced the corrosion rate with the corrosion current density by 59 and 81%, from 31.22 to 12.83 μA/cm² and 5.83 μA/cm² in the spin coating and dip coating groups, respectively. The dip coating group showed better corrosion resistance than the spin coating group with the lowest released hydrogen content (17.5 mL) and lowest pH value (8.23) and reducing the current density by 45%. In vitro, the relative growth rate was over 75% in all groups tested with MG63, demonstrating that the Mg substrate and coating materials were within the safety range. The dip coating and spin coating groups enhanced the cell proliferation with significantly higher OD values (3.3, 3.0, and 2.5, respectively) and had better antihemolysis and antiplatelet adhesion abilities than the uncoated group. The two coating methods showed no difference in the cellular response, cell migration, hemolysis, and platelet adhesion test. In in vivo tests in rats, the dip coating group also showed a higher corrosion resistance with a lower corrosion rate and mass loss than the spin coating group. In addition, the blood biochemistry and histopathology results indicated that all materials used in this study were biocompatible with living subjects. The present research confirmed that the two methods have no noticeable difference in cell and organ response but the corrosion resistance of dip coating was higher than that of spin coating either in vitro or in vivo.

The Controversial Role of LPS in Platelet Activation In Vitro

Circulating platelets are responsible for hemostasis and thrombosis but are also primary sensors of pathogens and are involved in innate immunity, inflammation, and sepsis. Sepsis is commonly caused by an exaggerated immune response to bacterial, viral, and fungal infections, and leads to severe thrombotic complications. Among others, the endotoxin lipopolysaccharide (LPS) found in the outer membrane of Gram-negative bacteria is the most common trigger of sepsis. Since the discovery of the expression of the LPS receptor TLR4 in platelets, several studies have investigated the ability of LPS to induce platelet activation and to contribute to a prothrombotic phenotype, per se or in combination with plasma proteins and platelet agonists. This issue, however, is still controversial, as different sources, purity, and concentrations of LPS, different platelet-purification protocols, and different methods of analysis have been used in the past two decades, giving contradictory results. This review summarizes and critically analyzes past and recent publications about LPS-induced platelet activation in vitro. A methodological section illustrates the principal platelet preparation protocols and significant differences. The ability of various sources of LPS to elicit platelet activation in terms of aggregation, granule secretion, cytokine release, ROS production, and interaction with leukocytes and NET formation is discussed.

MicroRNA-26b Attenuates Platelet Adhesion and Aggregation in Mice

Platelets are key regulators of haemostasis, making platelet dysfunction a major driver of thrombosis. Numerous processes that determine platelet function are influenced by microRNAs (miRs). MiR-26b is one of the highest-expressed miRs in healthy platelets, and its expression in platelets is changed in a diseased state. However, the exact effect of this miR on platelet function has not been studied yet. In this study, we made use of a whole-body knockout of miR-26b in ApoE-deficient mice in order to determine its impact on platelet function, thrombus formation and platelet signalling both ex vivo and in vivo. We show that a whole-body deficiency of miR-26b exacerbated platelet adhesion and aggregation ex vivo. Additionally, in vivo, platelets adhered faster, and larger thrombi were formed in mice lacking miR-26b. Moreover, isolated platelets from miR-26b-deficient mice showed a hyperactivated Src and EGFR signalling. Taken together, we show here for the first time that miR-26b attenuates platelet adhesion and aggregation, possibly through Src and EGFR signalling.

Inhibition of LDHA to Induce EEF2 Release Enhances Thrombocytopoiesis

Translation is essential for megakaryocyte (MK) maturation and platelet production. However, how the translational pathways are regulated in this process remains unknown. In this study, we found that megakaryocyte/platelet-specific lactate dehydrogenase A (LdhA)-knockout mice showed an increased number of platelets with remarkably accelerated MK maturation and proplatelet formation. Interestingly, the role of LDHA in MK maturation and platelet formation did not depend on lactate content, which was the major product of LDHA. Mechanism studies revealed that LDHA interacted with eukaryotic elongation factor 2 (eEF2) in the cytoplasm, controlling the participation of eEF2 in translation at the ribosome. Furthermore, the interaction of LDHA and eEF2 was dependent on NADH, a coenzyme of LDHA. NADH-competitive inhibitors of LDHA could release eEF2 from the LDHA pool, up-regulate translation and enhance MK maturation in vitro. Among LDHA inhibitors, stiripentol significantly promoted the production of platelets in vivo under physiological state and in the immune thrombocytopenia model. Moreover, stiripentol could promote platelet production from human cord blood mononuclear cells (CBMCs)-derived megakaryocytes, and also have a superposed effect with romiplostim. In short, this study reveals a novel non-classical function of LDHA in translation and may serve as a potential target for thrombocytopenia therapy.

Association Between Platelet Levels on Admission and 90-day Mortality in Patients With Exertional Heatstroke, a 10 Years Cohort Study

Background: Heatstroke is a common clinical symptom in summer with high mortality requiring identification of appropriate and rapid methods of assessment.

Method: This is a retrospective study that included the recent 10 years clinical data of heatstroke patients. A total of n = 186 patients were included in this study and grouped based on platelet (PLT) abnormality observed on admission.

Results: In the study group, n = 120 patients (64.5%) patients had normal PLT and n = 66 patients (35.5%) had abnormal PLT. Compared with PLT-normal group, PLT-abnormal group had higher Acute Physiology and Chronic Health Evaluation II (APACHE II) scores [median 15.0 (IQR 11.5–21.5) vs. 9.0 (IQR 7.0–12.5)] and SOFA scores [median 6.0 (IQR 4.0–10.0) vs. 2.0 (IQR 2.0–4.0)], lower Sequential Organ Failure Assessment (GCS)[median 8.0 (IQR 5.0–12.0) vs. 13.0 (IQR 9.0–14.0)]. The PLT-abnormal group had severe organ damage, including damage to the coagulation system, liver, and kidney (all p < 0.05). Significant differences were noted in 90-day survival between the two groups even after correction for Age, GCS, White blood cell count (WBC), Neutrophil, International normalized ratio (INR), Activated partial thromboplastin time (APTT), Procalcitonin (PCT), Alanine aminotransferase (ALT), Creatine (CR), D-Dime (D-D) (Before correction P < 0.001; After correction P = 0.009).The area under the ROC curve for the prediction of mortality based on PLT was 80.7% (95% CI 0.726–0.888, P < 0.001), the optimal cutoff value was 94, the sensitivity was 77.3%, and the specificity was 82.6%.

Conclusion: Patients with heatstroke with platelet abnormalities during admission have more severe organ impairment and a lower 90-day survival rate even when adjusted for other factors.

DMAG, a novel countermeasure for the treatment of thrombocytopenia

Background

Thrombocytopenia is one of the most common hematological disease that can be life-threatening caused by bleeding complications. However, the treatment options for thrombocytopenia remain limited.

Methods

In this study, giemsa staining, phalloidin staining, immunofluorescence and flow cytometry were used to identify the effects of 3,3ʹ-di-O-methylellagic acid 4ʹ-glucoside (DMAG), a natural ellagic acid derived from Sanguisorba officinalis L. (SOL) on megakaryocyte differentiation in HEL cells. Then, thrombocytopenia mice model was constructed by X-ray irradiation to evaluate the therapeutic action of DMAG on thrombocytopenia. Furthermore, the effects of DMAG on platelet function were evaluated by tail bleeding time, platelet aggregation and platelet adhesion assays. Next, network pharmacology approaches were carried out to identify the targets of DMAG. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were performed to elucidate the underling mechanism of DMAG against thrombocytopenia. Finally, molecular docking simulation, molecular dynamics simulation and western blot analysis were used to explore the relationship between DAMG with its targets.

Results

DMAG significantly promoted megakaryocyte differentiation of HEL cells. DMAG administration accelerated platelet recovery and megakaryopoiesis, shortened tail bleeding time, strengthened platelet aggregation and adhesion in thrombocytopenia mice. Network pharmacology revealed that ITGA2B, ITGB3, VWF, PLEK, TLR2, BCL2, BCL2L1 and TNF were the core targets of DMAG. GO and KEGG pathway enrichment analyses suggested that the core targets of DMAG were enriched in PI3K–Akt signaling pathway, hematopoietic cell lineage, ECM-receptor interaction and platelet activation. Molecular docking simulation and molecular dynamics simulation further indicated that ITGA2B, ITGB3, PLEK and TLR2 displayed strong binding ability with DMAG. Finally, western blot analysis evidenced that DMAG up-regulated the expression of ITGA2B, ITGB3, VWF, p-Akt and PLEK.

Conclusion

DMAG plays a critical role in promoting megakaryocytes differentiation and platelets production and might be a promising medicine for the treatment of thrombocytopenia.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s10020-021-00404-1.

Evaluation of the New Beckmann Coulter Analyzer DxH 900 Compared to Sysmex XN20: Analytical Performance and Flagging Efficiency

Efficiency and accuracy in automated hematology analyzers are very important for clinical laboratories. The purpose was to evaluate the flags and results reported by the newest Beckman Coulter analyzer DxH 900 compared to the Sysmex XN20 system. Samples were analyzed on the XN20 (Sysmex, Kobe, Japan) and on the Beckman Coulter DxH 900 (Beckman Coulter, Miami, Florida, USA). Slide reviews were performed microscopically. Morphologic criteria were used to identify abnormal cells as recommended by International Consensus Group for Hematology (ICSH): blasts, immature granulocytes (IG%), abnormal lymphocytes (ALs) and plasma cells. Results: there was a strong correlation between the analyzers in almost all clinical parameters tested. Both DxH 900 and XN20 showed an excellent degree of association for the leukocyte differential compared to the reference method (manual microscopy). When it comes to IG%, XN20 showed a positive bias for higher results. Related to platelets, there are no differences between the two methods for PLT count. For mean platelet volume (MPV), DxH 900 provided 100% results of the samples analyzed while XN20 while in the XN20 analyzer, 16% of the results were missing. From our results we came to the conclusion that both analyzers, DxH 900 and XN20 were clinically accurate and efficient. Abnormal Lymphocyte detection highlighted the differences between the two technologies as only minimal agreement was obtained. DxH 900 demonstrated higher sensitivity in detecting IG with good correlation with microscopic review. The DxH 900 for platelet clumps identification provides an excellent flag (PLT Clumps) with the highest sensitivity observed in our evaluation.

World Workshop on Oral Medicine VII: Bleeding control interventions for invasive dental procedures in patients with inherited functional platelet disorders: A systematic review

OBJECTIVES

The objective of this study was to determine bleeding control interventions (BCIs) that were reported to be effective in controlling postoperative bleeding in patients with inherited functional platelet disorders (IFPDs) undergoing invasive dental procedures.

STUDY DESIGN

We searched MEDLINE/PubMed, Embase, Cochrane Library (Wiley), and Scopus from 1960 through April 2020 for studies on patients with IFPD undergoing invasive dental procedures. Two reviewers conducted assessments independently.

RESULTS

We found a total of 620 nonduplicate published articles, of which 32 studies met our inclusion criteria. Management with BCI in patients with IFPD included in this systematic review was effective in 80.7% of treatment sessions. Local measures used intraoperatively were found to be effective. Three different protocols of BCI were noted; the most effective protocol consisted of antifibrinolytics, scaffold/matrix agents, and sutures (P < .01). An adjunct protocol consisting of a tissue sealant was also effective (P < .01). A third protocol of platelet transfusion and antifibrinolytics was ineffective in controlling postoperative bleeding in 4 of 6 dental sessions.

CONCLUSIONS

This systematic review supports the use of local measures intraoperatively and antifibrinolytics postoperatively. It also supports making decision regarding platelet transfusion based on the clinician's clinical judgment and medical history of the individual patient.

Platelet heterogeneity enhances blood clot volumetric contraction: An example of asynchrono-mechanical amplification

Physiological processes such as blood clotting and wound healing as well as pathologies such as fibroses and musculoskeletal contractures, all involve biological materials composed of a contracting cellular population within a fibrous matrix, yet how the microscale interactions among the cells and the matrix lead to the resultant emergent behavior at the macroscale tissue level remains poorly understood. Platelets, the anucleate cell fragments that do not divide nor synthesize extracellular matrix, represent an ideal model to study such systems. During blood clot contraction, microscopic platelets actively pull fibers to shrink the macroscale clot to less than 10% of its initial volume. We discovered that platelets utilize a new emergent behavior, asynchrono-mechanical amplification, to enhanced volumetric material contraction and to magnify contractile forces. This behavior is triggered by the heterogeneity in the timing of a population of actuators. This result indicates that cell heterogeneity, often attributed to stochastic cell-to-cell variability, can carry an essential biophysical function, thereby highlighting the importance of considering 4 dimensions (space + time) in cell-matrix biomaterials. This concept of amplification via heterogeneity can be harnessed to increase mechanical efficiency in diverse systems including implantable biomaterials, swarm robotics, and active polymer composites.

Synthetic platelet microgels containing fibrin knob B mimetic motifs enhance clotting responses

Native platelets are crucial players in wound healing. Key to their role is the ability of their surface receptor GPIIb/IIIa to bind fibrin at injury sites, thereby promoting clotting. When platelet activity is impaired as a result of traumatic injury or certain diseases, uncontrolled bleeding can result. To aid clotting and tissue repair in cases of poor platelet activity, our lab has previously developed synthetic platelet-like particles capable of promoting clotting and improving wound healing responses. These are constructed by functionalizing highly deformable hydrogel microparticles (microgels) with fibrin-binding ligands including a fibrin-specific whole antibody or a single-domain variable fragment. To improve the translational potential of these clotting materials, we explored the use of fibrin-binding peptides as cost-effective, robust, high-specificity alternatives to antibodies. Herein, we present the development and characterization of soft microgels decorated with the peptide AHRPYAAK that mimics fibrin knob 'B' and targets fibrin hole 'b'. These "Fibrin-Affine Microgels with Clotting Yield" (FAMCY) were found to significantly increase clot density in vitro and decrease bleeding in a rodent trauma model in vivo. These results indicate that FAMCYs are capable of recapitulating the platelet-mimetic properties of previous designs while utilizing a less costly, more translational design.

[Congenital coagulation disorders in neurosurgical patients. Literature review and case series]

Congenital coagulation disorders account about 1-2% and can pose a serious risk for neurosurgical patients. Indeed, coagulation management in these patients is essential to ensure normal hemostasis. Analysis of available literature devoted to this issue and case series of neurosurgical patients with congenital coagulation disorders. Literature data were obtained from the PubMed, Cochrane Library, Medline and Google Scholar databases for the period from 2019 to 2020. Over 200 reports devoted to our scientific issue were selected. We determined the key features of perioperative management of neurosurgical patients with congenital coagulation disorders. We have also analyzed 10 similar patients for the period from 2008 to 2020. Comprehensive analysis of anamnesis, adequate diagnosis, perioperative planning and multidisciplinary approach are essential for successful elective surgery in patients with congenital coagulation disorders.

Platelet-like particles improve fibrin network properties in a hemophilic model of provisional matrix structural defects

Following injury, a fibrin-rich provisional matrix is formed to stem blood loss and provide a scaffold for infiltrating cells, which rebuild the damaged tissue. Defects in fibrin network formation contribute to impaired healing outcomes, as evidenced in hemophilia. Platelet-fibrin interactions greatly influence fibrin network structure via clot contraction, which increases fibrin density over time. Previously developed hemostatic platelet-like particles (PLPs) are capable of mimicking platelet functions including binding to fibrin fibers, augmenting clotting, and inducing clot retraction. In this study, we aimed to apply PLPs within a plasma-based in vitro hemophilia B model of deficient fibrin network structure to determine the ability of PLPs to improve fibrin structure and wound healing responses within hemophilia-like abnormal fibrin network formation. PLP impact on structurally deficient clot networks was assessed via confocal microscopy, a micropost deflection model, atomic force microscopy and an in vitro wound healing model of early cell migration within a provisional fibrin matrix. PLPs improved clot network density, force generation, and stiffness, and promoted fibroblast migration within an in vitro model of early wound healing under hemophilic conditions, indicating that PLPs could provide a biomimetic platform for improving wound healing events in disease conditions that cause deficient fibrin network formation.

Fully automated platelet isolation on a centrifugal microfluidic device for molecular diagnostics

Platelets play crucial roles in hemostasis and immunity. Over the last decades, clinical evidence has revealed the significance of platelets as complementary biomarkers for the detection and treatment of various diseases, including cancer. Due to a lack of well standardized convenient isolation methods for platelets, pre-analytical factors such as complex handling procedures negatively impact the quality of the platelet samples, including overactivation, low purity, and poor reproducibility. This may lead to biased interpretation of various downstream analyses, such as proteomic and genomic analyses. Herein, we describe a fully automated lab-on-a-disc-based method of platelet isolation from a small volume of blood (<1 mL). This method provides higher yields (>4 folds) and purity (>99%) and lower platelet activation than the conventional method. Moreover, it was also superior in the detection of platelet-related RNAs CD41, PF4, and P2Y12 due to lower contamination with white blood cells.

Measurement of Platelet Function in an Experimental Stroke Model With Aspirin and Clopidogrel Treatment

Dual antiplatelet treatment (DAPT) increases the risk of tPA-associated hemorrhagic transformation (HT) in ischemic stroke. To investigate the effects of DAPT in rodents, reliable indicators of platelet function utilizing a minimally invasive procedure are required. We here established a fluorescence-based assay to monitor DAPT efficiency in a mouse model of ischemic stroke with HT. Male C57/BL6 mice were fed with aspirin and clopidogrel (ASA+CPG). Venous blood was collected, stimulated with thrombin, labeled with anti-CD41-FITC and anti-CD62P-PE, and analyzed by flow cytometry. Subsequently, animals were subjected to experimental stroke and tail bleeding tests. HT was quantified using NIH ImageJ software. In ASA+CPG mice, the platelet activation marker CD62P was reduced by 40.6 ± 4.2% (p < 0.0001) compared to controls. In vitro platelet function correlated inversely with tail bleeding tests (r = −0.8, p = 0.0033, n = 12). Twenty-four hours after drug withdrawal, platelet activation rates in ASA+CPG mice were still reduced by 20.2 ± 4.1% (p = 0.0026) compared to controls, while tail bleeding volumes were increased by 4.0 ± 1.4 μl (p = 0.004). Conventional tests using light transmission aggregometry require large amounts of blood and thus cannot be used in experimental stroke studies. In contrast, flow cytometry is a highly sensitive method that utilizes small volumes and can easily be incorporated into the experimental stroke workflow. Our test can be used to monitor the inhibitory effects of DAPT in mice. Reduced platelet activation is indicative of an increased risk for tPA-associated cerebral hemorrhage following experimental stroke. The test can be applied to individual animals and implemented flexibly prior and subsequent to experimental stroke.

Rat 90-day oral toxicity study of a novel coccidiostat - Ethanamizuril

In the current study, to support the safety assessment of ethanamizuril as a new potent anticoccidial agent of triazine compounds, a 90-day repeated-dose oral toxicity assay of ethanamizuril was investigated. Treatment related clinical signs of alopecia on back and neck have been observed in some male and female at the 65 and 130 mg/kg dose groups. The body weight and feed conversion efficacy of 65 and 130 mg/kg females and 65 mg/kg males were significantly increase than those of the control in treatment time, but noted decreased in the 130 mg/kg males. Dose related changes of hematologic and biochemical parameters such as MCV, MCH, TG, and the significant increased in the organ weight and the relative organ weight of the liver, kidney, heart, lung and spleen in both genders in the 65 and 130 mg/kg treated groups were observed. Furthermore, histopathological observations revealed that 65 and 130 mg/kg ethanamizuril induced pathological damage such as hepatocyte steatosis and focal necrosis, renal tubular atrophy, tubule protein casts. Fortunately, the observed toxicities were recoverable in convalescence. The results indicated that liver, kidneys and lung were the main target organs. The NOAEL of ethanamizuril for rats was estimated to be 20 mg/kg dietary dose level.

ATAT1 regulates forebrain development and stress-induced tubulin hyperacetylation

α-Tubulin acetyltransferase 1 (ATAT1) catalyzes acetylation of α-tubulin at lysine 40 in various organisms ranging from Tetrahymena to humans. Despite the importance in mammals suggested by studies of cultured cells, the mouse Atat1 gene is non-essential for survival, raising an intriguing question about its real functions in vivo. To address this question, we systematically analyzed a mouse strain lacking the gene. The analyses revealed that starting at postnatal day 5, the mutant mice display enlarged lateral ventricles in the forebrain, resembling ventricular dilation in human patients with ventriculomegaly. In the mice, ventricular dilation is due to hypoplasia in the septum and striatum. Behavioral tests of the mice uncovered deficits in motor coordination. Birth-dating experiments revealed that neuronal migration to the mutant septum and striatum is impaired during brain development. In the mutant embryonic fibroblasts, we found mild defects in cell proliferation and primary cilium formation. Notably, in these cells, ATAT1 is indispensable for tubulin hyperacetylation in response to high salt, high glucose, and hydrogen peroxide-induced oxidative stress. We investigated the role of ATAT1 in the hematopoietic system using multicolor flow cytometry and found that this system remains normal in the mutant mice. Although tubulin acetylation was undetectable in a majority of mutant tissues, residual levels were detected in the heart, skeletal muscle, trachea, oviduct, thymus and spleen. This study thus not only establishes the importance of ATAT1 in regulating mouse forebrain development and governing tubulin hyperacetylation during stress responses, but also suggests the existence of an additional α-tubulin acetyltransferase.

Effects of platelet-rich plasmapheresis during cardiovascular surgery: A meta-analysis of randomized controlled clinical trials

OBJECTIVE

This study aimed to explore the effects of platelet-rich plasmapheresis (PRP) on the amount of postoperative blood loss and the requirements for allogeneic fresh frozen plasma (FFP) and red blood cell (RBC) transfusions during cardiovascular surgery.

METHODS

A literature search of 7 online databases was conducted. Randomized control trials (RCT) comparing intraoperative PRP or appropriate control groups were considered suitable for this current study.

RESULTS

Fifteen RCTs enrolling a total of 1002 patients, including 501 patients who received PRP and 501 control patients. Meta-analysis of the data from these trials showed that PRP reduced the total volume of postoperative blood loss (standardized mean difference [SMD], -0.74; 95% confidence interval [CI], -1.18 to -0.31; P < 0.05), reduced postoperative fresh frozen plasma (FFP) transfusion (SMD, -0.38; 95%CI, -0.69 to -0.08; P < 0.05), reduced postoperative RBCs transfusion (SMD, -0.44; 95%CI, -0.77 to -0.10; P < 0.05), and reduced the proportion of patients receiving postoperative allogeneic RBC transfusions (relative risk [RR], 0.44; 95%CI, 0.21-0.91, P < 0.05) during cardiovascular surgery.

CONCLUSION

Conducting PRP before cardiopulmonary bypass (CPB) and transfusing autologous platelet-rich plasma (aPRP) after reversal of heparin could reduce postoperative blood loss, the requirements for blood products transfusion during cardiovascular surgery. A higher mean platelet count in aPRP may improve the final outcome. However, there was a high degree of undetermined heterogeneity among the analyzed trials, and larger and more precise RCTs are needed to confirm these conclusions.

Platelet proteomics: from discovery to diagnosis

INTRODUCTION

Platelets are the smallest cells within the circulating blood with key roles in physiological hemostasis and pathological thrombosis regulated by the onset of activating/inhibiting processes via receptor responses and signaling cascades. Areas covered: Proteomics as well as genomic approaches have been fundamental in identifying and quantifying potential targets for future diagnostic strategies in the prevention of bleeding and thrombosis, and uncovering the complexity of platelet functions in health and disease. In this article, we provide a critical overview on current functional tests used in diagnostics and the future perspectives for platelet proteomics in clinical applications. Expert commentary: Proteomics represents a valuable tool for the identification of patients with diverse platelet associated defects. In-depth validation of identified biomarkers, e.g. receptors, signaling proteins, post-translational modifications, in large cohorts is decisive for translation into routine clinical diagnostics.

Platelet Abnormalities in the Oral Maxillofacial Surgery Patient

Platelet abnormalities result from a wide range of congenital and acquired conditions, which may be known or unknown to patients presenting for oral maxillofacial surgery. It is critical to obtain a thorough history, including discussion of any episodes of bleeding or easy bruising, to potentially discern patients with an underlying platelet disorder. If patients indicate a positive history, preoperative laboratory studies are indicated, with potential referral or consultation with a hematologist. Appropriate preoperative planning may reduce the risk of bleeding associated with platelet dysfunction, potentially avoiding serious perioperative and postoperative complications.