Platelet Dysfunction Research Articles

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

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

Successful transarterial embolization of hemorrhage following percutaneous liver biopsy in hepatic amyloidosis.

Percutaneous liver biopsy is essential for diagnosing hepatic amyloidosis. Post biopsy hemorrhage is unusual but can occur. The potential for bleeding can result from various factors, such as the deposition of amyloid in the hepatic parenchyma or vessel wall, deficiencies in coagulation factors, hyperfibrinolysis, and platelet dysfunction. Transarterial embolization can be a safe and effective method for achieving hemostasis.

Activation of the HMGB1-TLR4 pathway impacts the functionality of bone marrow mesenchymal stem cells and disrupts macrophage polarization in immune thrombocytopenia.

Recent evidence suggests that immune thrombocytopenia (ITP), a common bleeding disorder, is linked to an imbalance in macrophage polarization and impaired bone marrow mesenchymal stem cells (BMSCs). However, the relationship between macrophage polarization imbalance and functional defects in BMSCs, as well as the involvement of associated molecules in BMSCs' defects, is not well understood. This study aimed to investigate the regulatory effects of high mobility group protein 1 (HMGB1) on the physiological functions of BMSCs, specifically in relation to macrophage polarization imbalance. Patients with ITP showed dysregulation in monocyte/macrophage polarization and impaired BMSCs function. HMGB1 was found to have a negative impact on the ability of BMSCs to regulate the imbalance in macrophage polarization, especially when inflammatory factors are present. The MyD88-dependent pathway downstream of BMSCs was found to be significantly enhanced with HMGB1 treatment. Furthermore, treatment with toll-like receptor 4 (TLR4) inhibitors successfully restored the regulatory capacity of BMSCs in ameliorating macrophage polarization imbalance and effectively inhibited the activation of the MyD88-dependent pathway. Meanwhile, infusion of si-TLR4-BMSCs reversed HMGB1-induced platelet dysfunction and reduced over-polarization to M1-like macrophages in the ITP mouse model. Consequently, targeting the HMGB1-TLR4 pathway could be a potential approach to restore the immunoregulatory function of BMSCs.

Migraine and Stroke: A Scoping Review.

An increased risk of ischemic stroke in migraine with aura (MA) has been consistently demonstrated. The pathophysiology of risk factors is not yet well understood. Several mechanisms have been proposed to explain the association between MA and ischemic stroke including decreased focal cerebral blood flow and other phenomena linked with cortical spreading depression (CSD) as well as neurovascular pathology, which appear to play a key role in MA. In addition to genetic predisposition, other classic stroke risk factors such as atrial fibrillation, emboli, migraine-associated vasculopathy, endothelial dysfunction, platelet dysfunction, coagulation pathway abnormalities, and inflammatory factors have been examined and investigated. For further clarification, distinctions have been made between features of migrainous infarctions and non-migrainous infarctions among migraineurs. Furthermore, the association is less clear when considering the mixed results studying the risk of ischemic stroke in migraines without aura (MO) and the risk of hemorrhagic stroke in people with all types of migraine. Translational research is investigating the role of biomarkers which can help identify vascular links between stroke and migraine and lead to further treatment developments. We performed a scoping review of the PubMed database to further characterize and update the clinical connections between migraine and stroke.

Patients with Waldenström macroglobulinemia have impaired platelet and coagulation function

AbstractClinical features in patients with the B-cell lymphoma, Waldenström macroglobulinemia (WM), include cytopenias, immunoglobulin M (IgM)–mediated hyperviscosity, fatigue, bleeding, and bruising. Therapeutics such as Bruton's tyrosine kinase inhibitors (BTKis) exacerbate bleeding risk. Abnormal hemostasis arising from platelet dysfunction, altered coagulation or vascular impairment have not yet been investigated in patients with WM. Therefore, this study aimed to evaluate hemostatic dysfunction in samples from these patients. Whole blood (WB) samples were collected from 14 patients with WM not receiving therapy, 5 patients receiving BTKis and 15 healthy donors (HDs). Platelet receptor levels and reticulation were measured by flow cytometry, plasma thrombin generation with or without platelets by fluorescence resonance energy transfer assay, WB clotting potential by rotational thromboelastometry, and plasma soluble glycoprotein VI (sGPVI) and serum thrombopoietin (TPO) by enzyme-linked immunosorbent assay. Donor platelet spreading, aggregation, and ability to accelerate thrombin generation in the presence of WM-derived IgM were assessed. WM platelet receptor levels, responses to physiological agonists, and plasma sGPVI were within normal ranges. WM platelets had reduced reticulation (P = .0012) whereas serum TPO levels were increased (P = .0040). WM plasma displayed slower thrombin generation (P = .0080) and WM platelets contributed less to endogenous thrombin potential (ETP; P = .0312). HD plasma or platelets incubated with IgM (50-60 mg/mL) displayed reduced spreading (P = .0002), aggregation (P < .0001), and ETP (P = .0081). Thus, alterations to thrombin potential and WB coagulation were detected in WM samples. WM IgM significantly impaired hemostasis in vitro. Platelet and coagulation properties are disturbed in patients with well-managed WM.

Mitochondrial dysfunction in platelets from severe trauma patients - A prospective case-control study

IntroductionTrauma-induced coagulopathy (TIC) refers to an abnormal coagulation process, an imbalance between coagulation and fibrinolysis due to several pathological factors, such as haemorrhage and tissue injury. Platelet activation and subsequent clot formation are associated with mitochondrial activity, suggesting a possible role for mitochondria in TIC. Comprehensive studies of mitochondrial dysfunction in platelets from severe trauma patients have not yet been performed. MethodsIn this prospective case-control study, patients with severe trauma (ISS≥16) had venous blood samples taken at arrival to the Emergency Unit of a Level 1 Trauma Centre. Mitochondrial functional measurements (Oxygraph-2k, Oroboros) were performed to determine oxygen consumption in different respiratory states, the H2O2 production and extramitochondrial Ca2+ movements. In addition, standard laboratory and coagulation tests, viscoelastometry (ClotPro) and aggregometry (Multiplate) were performed. Measurements data were compared with age and sex matched healthy control patients. ResultsSevere trauma patients (n = 113) with a median age of 38 years (IQR, 20–51), a median ISS of 28 (IQR, 20–48) met our inclusion criteria. Oxidative phosphorylation in platelet mitochondria from severe trauma patients significantly decreased compared to controls (34.7 ± 8.8 pmol/s/mL vs. 48.0 ± 19.7 pmol/s/mL). The mitochondrial H2O2 production significantly increased and greater endogenous Ca2+ release was found in the polytrauma group. Consistent with these results, clotting time (CT) increased while maximum clot firmness (MCF) decreased with the EX-test and FIB-test in severe trauma samples. Multiplate aggregometry showed significantly decreased ADP-test (38 ± 12 AUC vs. 112 ± 14 AUC) and ASPI test (78 ± 22 AUC vs. 84 ± 28 AUC) also tended to decrease in mitochondria of polytrauma patients as compared with controls. Significant strong correlation has been demonstrated between mitochondrial OxPhos and MCF while it was negatively correlated with ISS (R2=0.448, P˂0.05), INR, CT and lactate level of patients. ConclusionsThe present study revealed that severe trauma is associated with platelet mitochondrial dysfunction resulting in reduced ATP synthesis and impaired extramitochondrial Ca2+ movement. These factors are required for platelet activation, recruitment and clot stability likely thus, platelet mitochondrial dysfunction contributes to the development of TIC.

Hallmarks for Thrombotic and Hemorrhagic Risks in Chronic Kidney Disease Patients.

Chronic kidney disease (CKD) is a global health issue causing a significant health burden. CKD patients develop thrombotic and hemorrhagic complications, and cardiovascular diseases are associated with increased hospitalization and mortality in this population. The hemostatic alterations are multifactorial in these patients; therefore, the results of different studies are varying and controversial. Endothelial and platelet dysfunction, coagulation abnormalities, comorbidities, and hemoincompatibility of the dialysis membranes are major contributors of hypo- and hypercoagulability in CKD patients. Due to the tendency of CKD patients to exhibit a prothrombotic state and bleeding risk, they require personalized clinical assessment to understand the impact of antithrombotic therapy. The evidence of efficacy and safety of antiplatelet and anticoagulant treatments is limited for end-stage renal disease patients due to their exclusion from major randomized clinical trials. Moreover, designing hemocompatible dialyzer membranes could be a suitable approach to reduce platelet activation, coagulopathy, and thrombus formation. This review discusses the molecular mechanisms underlying thrombotic and hemorrhagic risk in patients with CKD, leading to cardiovascular complications in these patients, as well as the evidence and guidance for promising approaches to optimal therapeutic management.

Developing a tool for assessing and communicating the expected difficulty of performing a tracheostomy

There are no guidelines for assessing and communicating the expected difficulty of a tracheostomy, leading to difficulties planning a percutaneous approach in intensive care or referring onwards to surgical teams. A Delphi process was used to develop a tool containing metrics which are relevant for either specialty and can be universally assessed by both. Palpable tracheal rings, prior surgery or radiotherapy to the anterior neck, uncorrectable clotting or platelet dysfunction, ability to extend the neck freely, and overlying vessels visible, palpable or on imaging were all found to be relevant. It is hoped this tool will aid communication between specialties.

Soluble platelet selectin and platelets in COVID-19: a multifaceted connection.

The COVID-19 pandemic has brought to light the intricate relationship between platelets, soluble platelet selectin (sP-selectin), and disease pathogenesis. Platelets, traditionally recognized for their role in hemostasis, have emerged as key contributors to the immunothrombotic complications observed in COVID-19 patients. Concurrently, elevated levels of sP-selectin, indicative of platelet activation and endothelial injury, have been consistently identified in COVID-19 patients and have shown associations with disease severity and adverse outcomes. This multifaceted connection underscores the pivotal role of platelets and sP-selectin in orchestrating thromboinflammation, vascular dysfunction, and disease progression in COVID-19. Platelet activation triggers the release of inflammatory mediators and promotes platelet-leukocyte interactions, amplifying the systemic inflammatory response and exacerbating endothelial injury. Additionally, platelet-derived factors contribute to microvascular thrombosis, further exacerbating tissue damage and organ dysfunction in severe COVID-19. Elevated sP-selectin levels serve as biomarkers for disease severity and prognostication, aiding in risk stratification and early identification of patients at higher risk of adverse outcomes. Therapeutic strategies targeting platelet dysfunction and sP-selectin-mediated pathways hold promise in mitigating thromboinflammation and improving outcomes in COVID-19 patients. Antiplatelet agents, platelet inhibitors, and anti-inflammatory therapies represent potential interventions to attenuate platelet activation, inhibit platelet-leukocyte interactions, and alleviate endothelial dysfunction. A comprehensive understanding of the multifaceted connection between platelets, sP-selectin, and COVID-19 pathogenesis offers opportunities for tailored therapeutic approaches aimed at mitigating thromboinflammation and improving patient outcomes in this complex and challenging clinical setting.

Diet and Nutraceuticals for treatment and prevention of primary and secondary stroke: Emphasis on nutritional antiplatelet and antithrombotic agents

Ischemic stroke is a devastating disease that causes morbidity and mortality. Malnutrition following ischemic stroke is common in stroke patients. During the rehabilitation, the death rates of stroke patients are significantly increased due to malnutrition. Nutritional supplements such as protein, vitamins, fish, fish oils, moderate wine or alcohol consumption, nuts, minerals, herbal products, food colorants, marine products, fiber, probiotics and Mediterranean diets have improved neurological functions in stroke patients as well as their quality of life. Platelets and their mediators contribute to the development of clots leading to stroke. Ischemic stroke patients are treated with thrombolytics, antiplatelets, and antithrombotic agents. Several systematic reviews, meta-analyses, and clinical trials recommended that consumption of these nutrients and diets mitigated the vascular, peripheral, and central complications associated with ischemic stroke (Fig. 2). Particularly, these nutraceuticals mitigated the platelet adhesion, activation, and aggregation that intended to reduce the risks of primary and secondary stroke. Although these nutraceuticals mitigate platelet dysfunction, there is a greater risk of bleeding if consumed excessively. Moreover, malnutrition must be evaluated and adequate amounts of nutrients must be provided to stroke patients during intensive care units and rehabilitation periods. In this review, we have summarized the importance of diet and nutraceuticals in ameliorating neurological complications and platelet dysfunction with an emphasis on primary and secondary prevention of ischemic stroke.

The Use of Clot Strength as a Predictor of Thrombosis in Peripheral Artery Disease

ObjectivesGraft/stent thrombosis is the leading cause of amputation in patients over 60, and while dual antiplatelet therapy is the standard of care, there is a significant variability in platelet response and limited guidance on measuring effectiveness. Thromboelastography with platelet mapping (TEG-PM) can objectively detail an individual’s coagulation profile, namely the strength of the clot and its response to antiplatelet medication. Although TEG-PM has been used for predicting postoperative bleeding and assessing platelet dysfunction in TBI, its application in thrombosis diseases such as peripheral artery disease (PAD) remains unexplored. The aim of this observational study was to determine if objective measures of clot strength could predict a high clinical risk of thrombosis. MethodsPatients > 60 years with peripheral artery disease (PAD) undergoing revascularization were prospectively evaluated from 2021-2023. They were clinically followed for one year to detect any thrombotic events. TEG-PM was used to objectively evaluate coagulation profiles in patients at 1, 3, 6, and 9 months. These follow-up periods were chosen based on studies showing that 1-3 month intervals in the first year after lower extremity revascularization (LER) optimize therapy and risk control. The TEG-PM data preceding a thrombotic/stenotic event in patients with thrombosis was compared to the last known well TEG-PM event in those without a thrombotic/stenotic event. We stratified the groups based on the occurrence of thrombosis/stenotic events. Descriptive statistics were applied to characterize each group and a chi-square test was conducted to assess the variance between both groups. An unpaired t-test was ran to identify differences in platelet function. ROC analysis was performed to determine the optimal TEG-PM cutoff for predicting a higher risk of thrombosis. ResultsOne hundred and fifty-eight patients were analyzed, from whom 28 (17.7%) experienced a thrombotic event. The thrombosis cohort exhibited significantly greater MAADP, MAFibrin, and MAThrombin [50.2 vs. 40.0, p<0.05], [18.19 vs. 14.64, p<0.05] and [63.8 vs. 58.5, p<0.05] respectively indicative of greater clot strength. By ROC analysis, the optimal predictor cutoff for MAADP, indicating a higher risk of thrombosis, was >42mm [p<0.05] with 82% sensitivity and 50% specificity. ConclusionsAn increase in clot strength was found to be predictive of thrombosis/stenosis within 30 days. Using a MAADP cutoff greater than 42mm might serve as an alternative approach to tailor the use of antiplatelet medication, potentially reducing the risk of thrombosis.

Trauma patients have reduced ex vivo flow-dependent platelet hemostatic capacity in a microfluidic model of vessel injury.

Trauma is the leading cause of death in individuals up to 45 years of age. Alterations in platelet function are a critical component of trauma-induced coagulopathy (TIC), yet these changes and the potential resulting dysfunction is incompletely understood. The lack of clinical assays available to explore platelet function in this patient population has hindered detailed understanding of the role of platelets in TIC. The objective of this study was to assess trauma patient ex vivo flow-dependent platelet hemostatic capacity in a microfluidic model. We hypothesized that trauma patients would have flow-regime dependent alterations in platelet function. Blood was collected from trauma patients with level I activations (N = 34) within 60 min of hospital arrival, as well as healthy volunteer controls (N = 10). Samples were perfused through a microfluidic model of injury at venous and arterial shear rates, and a subset of experiments were performed after incubation with fluorescent anti-CD41 to quantify platelets. Complete blood counts were performed as well as plasma-based assays to quantify coagulation times, fibrinogen, and von Willebrand factor (VWF). Exploratory correlation analyses were employed to identify relationships with microfluidic hemostatic parameters. Trauma patients had increased microfluidic bleeding times compared to healthy controls. While trauma patient samples were able to deposit a substantial amount of clot in the model injury site, the platelet contribution to microfluidic hemostasis was attenuated. Trauma patients had largely normal hematology and plasma-based coagulation times, yet had elevated D-Dimer and VWF. Venous microfluidic bleeding time negatively correlated with VWF, D-Dimer, and mean platelet volume (MPV), while arterial microfluidic bleeding time positively correlated with oxygenation. Arterial clot growth rate negatively correlated with red cell count, and positively with mean corpuscular volume (MCV). We observed changes in clot composition in trauma patient samples reflected by significantly diminished platelet contribution, which resulted in reduced hemostatic function in a microfluidic model of vessel injury. We observed a reduction in platelet clot contribution under both venous and arterial flow ex vivo in trauma patient samples. While our population was heterogenous and had relatively mild injury severity, microfluidic hemostatic parameters correlated with different patient-specific data depending on the flow setting, indicating potentially differential mechanistic pathways contributing to platelet hemostatic capacity in the context of TIC. These data were generated with the goal of identifying key features of platelet dysfunction in bleeding trauma patients under conditions of flow and to determine if these features correlate with clinically available metrics, thus providing preliminary surrogate markers of physiological platelet dysfunction to be further studied across larger cohorts. Future studies will continue to explore those relationships and further define mechanisms of TIC and their relationship with patient outcomes.

Utility of thromboelastography with platelet mapping for monitoring platelet transfusion in qualitative platelet disorders

BackgroundPatients with pathogenic variants in RASGRP2 (inherited platelet disorder (IPD)-18) exhibit normal platelet counts but impaired platelet aggregation and αIIbβ3 activation. Moderate-to-severe bleeding episodes require patients to be transfused with platelets and/or pro-hemostatic agents. We recently demonstrated that hemostatic efficacy of transfused platelets is limited by dysfunctional endogenous platelets in a mouse model of IPD-18 (Rasgrp2−/− mice), as dysfunctional platelets were recruited to the forming hemostatic plug but did not participate in clot contraction. Thus, higher amounts of transfused platelets were required to outcompete these dysfunctional cells and to reverse bleeding. ObjectiveWe here studied the usefulness of thromboelastography with platelet mapping (TEG-PM) for ex vivo monitoring of the hemostatic potential in Rasgrp2−/− mice transfused with various amounts of wild-type (WT) platelets. MethodsWhole blood (WB) samples from WT and Rasgrp2−/− mice were tested in TEG-PM and parameters for clot formation and contraction (K time, α-angle, maximum amplitude [MA]) were measured. ResultsRasgrp2−/− WB samples did not contract in TEG-PM, consistent with a critical role of this protein in αIIbβ3 activation. Addition of WT platelets improved TEG parameters in a ratio-dependent manner, consistent with our recent in vivo studies showing impaired hemostasis at a 5:1, but not at a 2:1 ratio of mutant to WT platelets. K and α values were identified as better predictors of transfusion efficacy than MA, the most platelet-dependent TEG parameter. ConclusionThis proof-of-concept study supports the use of TEG-PM to monitor platelet transfusion ratios and hemostatic potential in IPD-18 and potentially other platelet disorders.

Heat stress–induced platelet dysfunction is associated with loss of fibrinogen and is improved by fibrinogen supplementation

IntroductionHeatstroke is a critical heat-related condition characterized by coagulopathy and multiple organ dysfunction. One of the most severe complications of heatstroke is disseminated intravascular coagulation. This condition manifests as excessive clot formation and bleeding that are primarily due to platelet depletion and dysfunction. Fibrinogen plays a crucial role in hemostasis because it links integrin αIIbβ3 on adjacent platelets, thereby promoting the platelet activation and aggregation necessary for clot formation. However, reduced fibrinogen levels may impair the formation of the initial platelet plug and increase the risk of bleeding. The current study explored the effect of fibrinogen on platelet dysfunction in a heatstroke model. Materials and methodsMale Wistar rats were subjected to heat stress, and subsequent changes in hemodynamic, biochemical, and coagulation parameters were analyzed. Platelet viability, aggregation, adhesion, spreading and fibrin clot retraction were assessed. ResultsThe rats with heatstroke exhibited a variety of clinical symptoms, including hypotension, tachycardia, multiple organ dysfunction, and coagulopathy. Platelet viability in the heatstroke group was comparable to that in the healthy control group. However, the heatstroke group exhibited significant reductions in plasma fibrinogen levels and platelet aggregation, adhesion, spreading, and fibrin clot retraction. Notably, fibrinogen supplementation markedly augmented the aggregation responses of platelets in the heatstroke group. The impairment of platelet adhesion, spreading, and fibrin clot retraction in the rats with heatstroke was partially ameliorated by fibrinogen supplementation. ConclusionsAn early use of fibrinogen replacement may serve as a therapeutic intervention to alleviate platelet hyporeactivity and prevent the complications in patients with heatstroke.

ECMO produces very rapid changes in primary hemostasis detected by PFA-200 during lung transplantation: An observational study

BackgroundThe pathology of primary hemostasis is a common complication of extracorporeal membrane oxygenation (ECMO) support. Scientific data describing its changes in patients on short-term ECMO support and the ability and speed of the restoration of its functions are limited. AimsThe aim of this study was to describe the pathology of primary hemostasis induced by short-term ECMO support and its development over time using PFA-200®, ROTEM® platelet and von Willebrand factor (vWF) analyses. MethodsIn patients undergoing lung transplantation surgery using intra-operative veno-arterial ECMO support, blood samples were analyzed using the following tests: PFA-200®, ROTEM® platelet tests, vWF antigen, ristocetin cofactor (RCo) and collagen binding protein (CB) before, during and after ECMO support. ResultsBlood samples from 32 patients were analyzed. All three PFA-200® tests (COL/EPI, COL/ADP and COL/P2Y) showed significant deterioration during ECMO support with rapid restoration after ECMO cessation (p<0.05), suggesting an ECMO-induced primary hemostasis disorder. A significant increase of vWF antigen after ECMO cessation (p<0.05) was found with an increase of ristocetin cofactor and collagen binding protein levels, although it was not significant (p>0.05). ConclusionsShort-term ECMO support induces primary hemostasis pathology. It occurs immediately after initiation but is rapidly restored after ECMO cessation, which is detectable by PFA-200®. Despite there being persistent platelet dysfunction after ECMO cessation as seen with the ROTEM® platelet results, the increased levels of vWF antigen might explain the normal results of primary hemostasis detected by PFA-200®.

TRANSFUSION AND INFUSION THERAPY FOR MASSIVE BLOOD LOSS. PART 4. PHYSIOLOGICAL PREREQUISITES AND LIMITATIONS OF PLATELETS TRANSFUSION FOR HAEMOSTATIC RESUSCITATION

Platelets are the main component of primary haemostasis and participate in secondary, coagulation haemostasis. When bleeding from small vessels, primary (platelet) hemostasis can ensure the thrombus's stability, which is sufficient to stop the bleeding. In case of damage to medium and large vessels, stopping bleeding begins with the activation of platelets, but also requires the activation of the coagulation cascade with the involvement of internal and external coagulation pathways. Blood coagulation factors involved in internal, external and general coagulation pathways not only circulate in the blood but are carried by platelets. In addition, actin and myosin contained in platelets, take an active part already in the final phase of thrombus formation – in clot retraction. Platelets also contain growth factors that stimulate the healing of damaged blood vessels. For more than a decade, platelets have been an integral part of haemostatic resuscitation in cases of massive bleeding in trauma and wounds. The optimal ratio of platelets to red blood cells (RBC) and fresh frozen plasma (FFP) in trauma is 1:1:1, that is, to include a considerable number of platelets. With other variants of surgical massive bleeding, the optimal ratio may be different and the proportion of platelets to RBC, and the number of platelets is smaller. Platelets, like clotting factors, are consumed during thrombus formation and are also passively lost with the outflowing blood. The rate of loss of platelets is sometimes not directly proportional to the amount of blood loss and also depends on the haematocrit. Although during a full-scale war, the frequency of the development of massive bleeding in Ukraine is the highest in the world, to date, the logistical problems with the availability of platelets, especially at the stage of initial resuscitation, are still not resolved. Therefore, in this article, we provide ways to solve the situation, depending on the available resources. In civilian settings, the problem with platelets most often occurs because of intraoperative or traumatic bleeding in the background of taking antiplatelet agents, that is, inhibitors of platelet function. Taking antiplatelet agents can increase bleeding, and the physician needs to know how to restore lost platelet functions or how to replace these lost functions with platelet concentrate. In this publication, we will present the pathophysiological rationale for the importance of early recovery of the first phase of haemostasis - platelet aggregation by transfusion of platelet concentrate in case of traumatic massive bleeding. In addition, we present some methods that contribute to the preservation of platelets, as well as improving their functional activity. Other factors that increase the risk of developing MC are thrombocytopenia and thrombocytopenia caused by hereditary and acquired factors. Although haematologists treat such patients and should be involved as consultants, in this article we will briefly outline the most common treatment methods prescribed by haematologists. The factors that lead to platelet deficiency in the blood vary, but life-threatening bleeding treatment by platelet concentrate transfusion can be a common solution in many situations. If it is not possible to transfuse a sufficient number of platelets concentrate during life-threatening bleeding in patients with thrombocytopenia and platelet dysfunction, it may be transfused a fresh whole-blood.

Коагуляційні характеристики пуповинної крові при затримці росту плода

Fetal growth restriction (FGR) is a common complication of pregnancy associated with severe perinatal consequences, a significant part of which is hemorrhagic and thrombotic disorders. Fetuses with FGR have thrombocytopenia, platelet dysfunction, and distortion of standard coagulation tests. There are few studies of the coagulation system in such newborns in vivo in the literature. Аim - to assess the relationship between the Doppler criteria of FGR and the kinetic manifestations of umbilical artery blood coagulation and fibrinolysis according to rotational thromboelastometry. Materials and methods. Prenatal Doppler parameters and postpartum kinetic parameters of blood coagulation and fibrinolysis in 118 newborns from singleton births were analyzed: the Group I - 67 newborns with FGR; the Group II - 51 full-term newborns from healthy mothers. Results. A significant decrease in the uterine and umbilical arteries resistance and blood flow velocity in FGR cases has been established. Thromboelastometric tests in the umbilical cord blood of the Group I newborns showed faster than in the Group II the blood clot formation, its greater firmness and delayed fibrinolysis. Comparison using rank correlation showed a relationship of average strength between the velocity of blood flow in the umbilical cord arteries and the blood clot firmness. Correlation between blood flow velocity in the midbrain and uterine arteries and coagulation indicators are weak. Conclusions. Reduced resistance index in the middle cerebral artery of fetuses with FGR indicates reduced resistance in these vessels, which should be regarded as signs of decentralization of fetal circulation. The blood of newborns with FGR is dominated by the processes of increased coagulation and slowing down of fibrinolysis, regardless of the date of birth. An increase in the pulsation index in the umbilical cord arteries during pregnancy can be considered a prognostically favorable hemodynamic characteristic in FGR. The study was carried out in accordance with the principles of the Helsinki Declaration. The research protocol was approved by the Local Ethics Committee of the institution mentioned in the work. The authors declare that there is no conflict of interest.

Cerebral Intraparenchymal Hemorrhage due to Implantation of Electrodes for Deep Brain Stimulation: Insights from a Large Single-Center Retrospective Cross-Sectional Analysis

Cerebral intraparenchymal hemorrhage due to electrode implantation (CIPHEI) is a rare but serious complication of deep brain stimulation (DBS) surgery. This study retrospectively investigated a large single-center cohort of DBS implantations to calculate the frequency of CIPHEI and identify patient- and procedure-related risk factors for CIPHEI and their potential interactions. We analyzed all DBS implantations between January 2013 and December 2021 in a generalized linear model for binomial responses using bias reduction to account for sparse sampling of CIPHEIs. As potential risk factors, we considered age, gender, history of arterial hypertension, level of invasivity, types of micro/macroelectrodes, and implanted DBS electrodes. If available, postoperative coagulation and platelet function were exploratorily assessed in CIPHEI patients. We identified 17 CIPHEI cases across 839 electrode implantations in 435 included procedures in 418 patients (3.9%). Exploration and cross-validation analyses revealed that the three-way interaction of older age (above 60 years), high invasivity (i.e., use of combined micro/macroelectrodes), and implantation of directional DBS electrodes accounted for 82.4% of the CIPHEI cases. Acquired platelet dysfunction was present only in one CIPHEI case. The findings at our center suggested implantation of directional DBS electrodes as a new potential risk factor, while known risks of older age and high invasivity were confirmed. However, CIPHEI risk is not driven by the three factors alone but by their combined presence. The contributions of the three factors to CIPHEI are hence not independent, suggesting that potentially modifiable procedural risks should be carefully evaluated when planning DBS surgery in patients at risk.

FLI1 is associated with regulation of DNA methylation and megakaryocytic differentiation in FPDMM caused by a RUNX1 transactivation domain mutation

Familial platelet disorder with associated myeloid malignancies (FPDMM) is an autosomal dominant disease caused by heterozygous germline mutations in RUNX1. It is characterized by thrombocytopenia, platelet dysfunction, and a predisposition to hematological malignancies. Although FPDMM is a precursor for diseases involving abnormal DNA methylation, the DNA methylation status in FPDMM remains unknown, largely due to a lack of animal models and challenges in obtaining patient-derived samples. Here, using genome editing techniques, we established two lines of human induced pluripotent stem cells (iPSCs) with different FPDMM-mimicking heterozygous RUNX1 mutations. These iPSCs showed defective differentiation of hematopoietic progenitor cells (HPCs) and megakaryocytes (Mks), consistent with FPDMM. The FPDMM-mimicking HPCs showed DNA methylation patterns distinct from those of wild-type HPCs, with hypermethylated regions showing the enrichment of ETS transcription factor (TF) motifs. We found that the expression of FLI1, an ETS family member, was significantly downregulated in FPDMM-mimicking HPCs with a RUNX1 transactivation domain (TAD) mutation. We demonstrated that FLI1 promoted binding-site-directed DNA demethylation, and that overexpression of FLI1 restored their megakaryocytic differentiation efficiency and hypermethylation status. These findings suggest that FLI1 plays a crucial role in regulating DNA methylation and correcting defective megakaryocytic differentiation in FPDMM-mimicking HPCs with a RUNX1 TAD mutation.

Iron deficiency anemia and platelet dysfunction: A comprehensive analysis of the underlying mechanisms

AimsThis research aimed to study the changes in platelet function and their underlying mechanisms in iron deficiency anemia. Main methodsInitially, we evaluated platelet function in an IDA mice model. Due to the inability to accurately reduce intracellular Fe2+ concentrations, we investigated the impact of Fe2+ on platelet function by introducing varying concentrations of Fe2+. To probe the underlying mechanism, we simultaneously examined the dynamics of calcium in the cytosol, and integrin αIIbβ3 activation in Fe2+-treated platelets. Ferroptosis inhibitors Lip-1 and Fer-1 were applied to determine whether ferroptosis was involved in this process. Key findingsOur study revealed that platelet function was suppressed in IDA mice. Fe2+ concentration-dependently facilitated platelet activation and function in vitro. Mechanistically, Fe2+ promoted calcium mobilization, integrin αIIbβ3 activation, and its downstream outside-in signaling. Additionally, we also demonstrated that ferroptosis might play a role in this process. SignificanceOur data suggest an association between iron and platelet activation, with iron deficiency resulting in impaired platelet function, while high concentrations of Fe2+ contribute to platelet activation and function by promoting calcium mobilization, αIIbβ3 activation, and ferroptosis.