Changes In Platelet Morphology Research Articles

The platelet storage lesion, what are we working for?

Platelet concentrate (PC) transfusions are crucial in prevention and treatment of bleeding in infection, surgery, leukemia, and thrombocytopenia patients. Although the technology for platelet preparation and storage has evolved over the decades, there are still challenges in the demand for platelets in blood banks because the platelet shelf life is limited to 5 days due to bacterial contamination and platelet storage lesions (PSLs) at 20-24°C under constant horizontal agitation. In addition, the relations between some adverse effects of platelet transfusions and PSLs have also been considered. Therefore, understanding the mechanisms of PSLs is conducive to obtaining high quality platelets and facilitating safe and effective platelet transfusions. This review summarizes developments in mechanistic research of PSLs and their relationship with clinical practice, providing insights for future research. Authors conducted a search on PubMed and Web of Science using the professional terms "PSL" and "platelet transfusion." The obtained literature was then roughly categorized based on their research content. Similar studies were grouped into the same sections, and further searches were conducted based on the keywords of each section. Different studies have explored PSLs from various perspectives, including changes in platelet morphology, surface molecules, biological response modifiers (BMRs), metabolism, and proteins and RNA, in an attempt to monitor PSLs and identify intervention targets that could alleviate PSLs. Moreover, novel platelet storage conditions, including platelet additive solutions (PAS) and reconsidered cold storage methods, are explored. There are two approaches to obtaining high-quality platelets. One approach simulates the invivo environment to maintain platelet activity, while the other keeps platelets at a low activity level invitro under low temperatures. Understanding PSLs helps us identify good intervention targets and assess the therapeutic effects of different PSLs stages for different patients.

Reactive oxygen species downregulate dystroglycans in the megakaryocytes of rats with arterial hypertension

Hypertension is a multifactorial disease characterized by vascular and renal dysfunction, cardiovascular remodeling, inflammation, and fibrosis, all of which are associated with oxidative stress. We previously demonstrated cellular reactive oxygen species (ROS) imbalances may impact the structural and biochemical functions of blood cells and reported downregulation of β-dystroglycan (β-Dg) and overexpression of the epithelial sodium channel (ENaC) contribute to the pathophysiology of hypertension. In this study, we aimed to determine the expression of dystroglycans (Dg) and ENaC in platelet progenitors (megakaryocytes) and their surrounding niches. Thin sections of bone marrow from 5- and 28-week-old spontaneous hypertensive rats (SHR) were compared to age-matched normotensive rats (WKY). Cytometry and immunohistochemical assays demonstrated an oxidative environment in SHR bone marrow, characterized by high levels of myeloperoxidase and 3-nitrotyrosine and downregulation of peroxiredoxin II. In addition, transmission electron micrography and confocal microscopy revealed morphological changes in platelets and Mgks from SHR rats, including swollen mitochondria. Quantitative qRT-PCR assays confirmed downregulation of Dg mRNA and immunohistochemistry and western-blotting validated low expression of β-Dg, mainly in the phosphorylated form, in Mgks from 28-week-old SHR rats. Moreover, we observed a progressive increase in β-1 integrin expression in Mgks and extracellular matrix proteins in Mgk niches in SHR rats compared to WKY controls. These results indicate accumulation of ROS promotes oxidative stress within the bone marrow environment and detrimentally affects cellular homeostasis in hypertensive individuals.

Platelet morphology, ultrastructure and function changes in acute ischemic stroke patients based on structured illumination microscopy

Acute ischemic stroke (AIS) is the second leading cause of death worldwide. This study aims at assessing platelet morphology, ultrastructure and function changes of platelets in acute ischemic stroke (AIS) patients by the technique of Structured Illumination Microscopy (SIM). This assay collected platelet-rich plasma (PRP) from 11 AIS patients and 12 healthy controls. Each PRP sample was divided into 7 groups:1) rest group; 2) Thrombin-treated 5 min group; 3) Thrombin plus 2MeSAMP-treated 5 min group; 4) Thrombin plus Aspirin-treated 5 min group; 5) Thrombin-treated 1 h group; 6) Thrombin plus 2MeSAMP-treated 1 h group; 7) Thrombin plus Aspirin-treated 1 h group. SIM was applied to observe dense granules and α-granules morphology changes of platelet in AIS patients. FIJI was used to quantify the image data. We finally observed 1448 images of platelets within the 7 groups. In rest group, 7162 platelets were calculated platelet diameter, CD63 dots, average CD63-positive dots area, CD63-positive area per platelet, CD63-positive area Fov, VWF dots, average VWF-positive dots area, VWF-positive area per platelet and VWF-positive area Fov. ELISA was used to detect release of platelet factor 4 (PF4) of α-granules. The results showed that AIS patients had lower number and smaller area of platelet granules. Platelet α-granules of AIS patients concentrated to parenchymal-like fluorescent blocks in Thrombin-treated 1 h group. Antiplatelet drug treatment could reverse the concentration of platelets α-granules, and 2MeSAMP was more powerful than Aspirin in vitro. This study complemented detail information of platelet ultrastructure of AIS patients, provided a new perspective on the pathogenesis of AIS and the mechanism of antiplatelet drugs based on SIM and provided a reference for future related studies. SIM-based analysis of platelet ultrastructure may be useful for detecting antiplatelet drugs and AIS in the future.

A Prestressed Intracellular Biomechanical Model for the Platelet to Capture the Disc-to-Sphere Morphological Change from Resting to Activated State

This paper proposes a biomechanical platelet model with an intracellular prestressed assumption. The platelet structure is composed of a membrane cortex and a marginal band (MB). The membrane cortex is assumed in a spherical shape in its initial state and modeled using spring-network elements widely used for the similar membrane structure of red blood cells. The MB is modeled as one solid torus, which employs the hyperelastic material model, and is confined inside the cortex through a contact model. In the initial equilibrium state, the platelet has a stable, flat, and discoid shape. Upon activation, the possible mechanism of the unbinding rate of crosslink between the microtubules (MTs) is assumed to break the homogeneous stiffness of the MB, which causes the platelet to have a disc-to-sphere morphological transition. The numerical results and the experimental images of the MBs show good agreement. The proposed model provides a novelty in relating the mechanical property changes of the MB to the platelet morphological changes upon activation, thus, can provide a possible engineering tool to reveal the intriguing behavior of platelet upon activation.

Platelet count and plateletcrit: Potential haematological biomarkers for livedoid vasculopathy?

The pathogenesis of livedoid vasculopathy (LV) remains unknown. Although platelet activation occurs in LV, little research has been conducted on LV platelet morphology parameters. The purpose of this study was to investigate whether platelet morphology changes in LV and its clinical significance. Twenty-seven LV patients and 21 cutaneous small vessel vasculitis (CSVV) patients, all at the active stage, were included. Platelet parameters in active- and stable-stage LV and CSVV patients were compared. Correlations between these platelet parameters and LV composite clinical scores were analysed. LV patients' mean age was 25.48 years (range: 9-62 years), and 81.48% (22/27) were women and 18.52% (5/27) were men. The platelet counts and plateletcrit (PCT) levels were significantly elevated in LV patients compared with CSVV patients and in active-stage LV patients compared with stable-stage LV patients after treatment. LV patient composite clinical scores that reflected disease severity and activity were positively correlated with the platelet count and PCT levels. Altered platelet morphology was detected in LV patients. Platelet count and PCT might be haematological biomarkers for early prediction of LV activity and relapses and for differential identification between LV and CSVV.

Результати дослідження морфологічних особливостей і серотоніндепонувальної функції тромбоцитів у донорів крові

Blood transfusion service and its social component – donorship must be the priority areas of the state policy because the results of its work are of paramount importance. The main task of the blood transfusion service is supply of high quality components for blood transfusion therapy. Quality of blood components is compliance of properties and specifications of the blood component supplied to the recipient with the set standards. Strict order of conformance with the approved regulations and procedures is important at all technological states and is a cornerstone of blood transfusion service products quality. All actions, planned and implemented, starting with planning donorship and ending with the finished product manufacturing and storage conditions, are important for ensuring the quality as the final result. The purpose of the study was to determine the content of total, platelet and free serotonin in the plasma of primary and active blood donors for further use of the studied parameters to assess the quality of platelet concentrate. Materials and methods. 160 blood donors (118 men and 42 women) were examined, including 110 active donors (85 men and 25 women) who donated blood regularly at least 3 times a year and 50 primary reserve donors (32 men and 18 women), who donated blood for the first time. Primary reserve donors formed a control group. For the convenience of systematization and reproduction of scientific research results, objectification in comparing research data, all examined active donors, depending on the duration of donor experience and, accordingly, increasing the probability of occurrence of hidden platelet metabolism disorder, were divided into three subgroups: subgroup I – 51 donors (39 men and 12 women), whose donor experience lasted from 2 to 5 years; subgroup II – 31 donors (24 men and 7 women), duration of donor experience which ranged from 6 to 9 years; subgroup III – 28 donors (22 men and 6 women), whose donor experience lasted 10 years or more. The method of fractional determination of biological amines – serotonin – is presented in preliminarily dried biostrate specimens. The method described includes some extraction procedures with optimal controlled pH values necessary for isolating serotonin, producing fluorophors in accordance with orthophtaldialdehide and ninhydrin, the subsequent fluorimetric estimation of their levels being performed on the native fluorometer «БИАН». Results and discussion. It was found that active donors compared to control, have a level of free serotonin in peripheral blood platelets which was significantly higher. Biochemical shifts were revealed in the background of certain morphological changes of platelets. Possible pathophysiological mechanisms of the detected changes are discussed in the article. Conclusion. Active blood donation is accompanied by significant changes in the morphological parameters of platelets and the content of free serotonin in peripheral blood platelets. Further study of platelet hematopoiesis of active blood donors is required

Mean Platelet Volume and Platelet Distribution Width Correlate with Microvascular Complications in Egyptian People with Type 2 Diabetes Mellitus.

Type 2 diabetes is a part of metabolic syndrome associated with a higher risk of vascular complications. Diabetes is characterized by changes in platelet morphology, function, and platelet hyperactivity so, it's considered a prothrombotic condition. Morbidity and mortality in people with type 2 diabetes-related to micro and macrovascular complications. Novel biomarkers are needed to identify and treat people at higher risk. The main objective of this controlled cross-sectional study was to evaluate Platelet volume indices (PVI) in subjects with type 2 diabetes with and without complications in comparison to subjects without diabetes. Hundred and thirty-five subjects aged from 35 to 60 years were subdivided into 3 groups. Group A includes 55 subjects with type 2 diabetes with complications. Group B includes 45 subjects with type 2 diabetes without complications. Group C includes 35 normal healthy subjects. Detailed clinical history was taken. Also, PVI, fasting blood glucose (FBG), hemoglobin A1c, and creatinine were obtained. Mean Platelet Volume (MPV), Platelet Distribution Width (PDW), Plateletcrit (PCT), and Platelet large cell ratio (P-LCR) were significantly higher among subjects with retinopathy, nephropathy, and neuropathy than other subjects with diabetes who didn't develop complications (P<0.001). At cutoff value > 11.9 fL, MPV have diagnostic sensitivity 80% and specificity 97.8%. Whereas PDW >16.9fL has a sensitivity of 74.5% and specificity of 100% for diabetic microvascular complications (retinopathy, nephropathy, and neuropathy). MPV and PDW may be considered as possible biomarkers for the early detection of diabetic microvascular complications.

The Role and Molecular Mechanism of P2Y12 Receptors in the Pathogenesis of Atherosclerotic Cardiovascular Diseases

The P2Y receptor family is a class of G protein-coupled receptors activated primarily by adenosine triphosphate (ATP), adenosine diphosphate (ADP), uridine triphosphate (UTP) and uridine diphosphate (UDP). The P2Y12 receptor is expressed on platelets which mediates platelet aggregation and morphological changes. At the same time, during the process of vascular remodeling and atherosclerosis, ADP can also promote the migration and proliferation of vascular smooth muscle and endothelial cells through P2Y12 receptor activating. Furthermore, P2Y12 is involved in many signal transductions processes, such as intimal hyperplasia, monocyte infiltration and so on, which play an important role in immune inflammation and brain injury. In order to solve the diseases induced by P2Y12 receptor, inhibitors such as ticagrelor, clopidogrel were widely used for cardiovascular diseases. However, there were some problems, such as limited antithrombotic effect, remain unsolved. This article summarizes the role and molecular mechanism of P2Y12 receptors in the pathogenesis of cardiovascular-related diseases, providing in-depth expounding on the molecular mechanism of P2Y12 receptor inhibitors and contributing to the treatment of diseases based on P2Y12 receptors.

Targeting residual inflammatory risk in coronary disease: to catch a monkey by its tail

Patients with coronary disease remain at high risk for future cardiovascular events, even with optimal risk factor modification, lipid-lowering drugs and antithrombotic regimens. A myriad of inflammatory pathways contribute to progression of the atherosclerotic burden in these patients. Only in the last few years has the inflammatory biology of atherosclerosis translated into clinical therapeutic options. Low-dose colchicine can provide a clinically relevant reduction in the risk for composite and individual major cardiovascular outcomes in patients with acute and chronic coronary syndromes. Among others, its anti-inflammatory effects in atherosclerosis seem to be related to neutrophil recruitment and adhesion, inflammasome inhibition, and morphological changes in platelets and platelet aggregation. Future research is aimed at further elucidating its particular mechanism of action, as well as identifying patients with the highest expected benefit and evaluating efficacy in other vascular beds. These data will help to formulate the role of colchicine and other anti-inflammatory drugs in patients with coronary disease and atherosclerosis in general in the near future.

Doxorubicin-Loaded Platelets Conjugated with Anti-CD22 Mabs: A Novel Targeted Delivery System for B-Cell Lymphoma Treatment with Cardiac Avoidance

Objective: B-cell lymphoma accounts for approximately 85% of all adult non-Hodgkin's lymphoma cases. Chemotherapy remains the first-line treatment for B-cell lymphoma. However, cytotoxic drugs cause various adverse reactions in normal tissues and cells, thus limiting the applied dosage of chemotherapeutic agents and hampering their effects on tumor cells. Therefore, crucial requirements for effective cancer treatment include tumor-specific drug accumulation and the protection of normal tissues from cytotoxic effects.Methods: In this study, we developed a novel drug delivery system for lymphoma treatment: doxorubicin-loaded platelets that were conjugated with anti-CD22 monoclonal antibodies (mAbs) (DOX-platelet-CD22). Platelets are bio- and immune-compatible drug carriers that can prolong the circulation time of drugs. Anti-CD22 mAb-labeled platelets can precisely deliver doxorubicin to tumor cells. The conjugation of anti-CD22 mAbs and encapsulation of doxorubicin in platelets were confirmed using fluorescence microscopy. Scanning electron microscopy and platelet aggregation assay were used to analyze the potential changes in platelet morphology and function. The cytotoxicity of DOX-platelet-CD22 on myocardial cell was evaluated by CCK-8 assay and its anti-tumour effects were determined by CCK-8 assay, flow cytometry and DAPI staining. The possible mechanism was further investigated by reverse transcription-polymerase chain reaction (RT-PCR) and western blotting.Results: Anti-CD22 mAbs were successfully coupled to platelets loaded with doxorubicin with high drug loading and encapsulation efficiency. No significant changes in morphology and function were observed between native platelets and DOX-platelet-CD22. Further, doxorubicin in DOX-platelet-CD22 was released most rapidly in an acidic condition. In Raji cells treated with DOX-platelet-CD22, the intracellular DOX concentration significantly increased, the cell viability remarkably decreased and apoptosis was obviously induced. These results indicate that platelets conjugated anti-CD22 mAbs can improve the therapeutic effects of doxorubicin. Moreover, the viability of myocardial cells treated with DOX-platelet-CD22 were significantly increased compared with those treated with free doxorubicin, demonstrating that DOX-platelet-CD22 can reduce cardiotoxicity caused by doxorubicin. Compared with other groups, the expression levels of Bax, caspase-3, and caspase-9 were notably upregulated while the Bcl-2 expression was downregulated in Raji cells treated with DOX-platelet-CD22. These findings indicate that DOX-platelet-CD22 can improve the antitumor activity of doxorubicin through bcl-2/caspase-mediated apoptosis pathway.Conclusion: DOX-platelet-CD22 drug delivery system enhances the anti-tumor effects and reduces the adverse effects of doxorubicin, thus proposing a promising option for B-cell lymphoma treatment. DisclosuresNo relevant conflicts of interest to declare.

Клинико-лабораторные аспекты реактивных тромбоцитозов

The article deals with the cases of secondary acquired (reactive) thrombocytosis in patients with various diseases. Thrombocytosis was registered against the background of inflammatory diseases of an infectious and non-infectious nature, during surgical interventions. In all patients with reactive thrombocytosis, no morphological changes in platelets were detected by the method of Fonio light microscopy

Rapid analysis of streaming platelet images by semi-unsupervised learning.

We developed a fast and accurate deep learning approach employing a semi-unsupervised learning system (SULS) for capturing the real-time noisy, sparse, and ambiguous images of platelet activation. Outperforming several leading supervised learning methods when applied to segment various platelet morphologies, the SULS detects their complex boundaries at submicron resolutions and it massively decreases to only a few hours for segmenting streaming images of 45 million platelets that would have taken 40 years to annotate manually. For the first time, the fast dynamics of pseudopod formation and platelet morphological changes including membrane tethers and transient tethering to vessels are accurately captured.

Virulent Leptospira interrogans Induce Cytotoxic Effects in Human Platelets in vitro Through Direct Interactions.

Leptospirosis is a prevalent zoonotic disease, caused by bacteria of the genus Leptospira. Leptospirosis frequently leads to hemostatic disturbances, and the severe cases are marked by hemorrhages and low platelet number in circulation, which is associated with the patients’ poor outcomes. Nevertheless, Leptospira-platelet interactions remain poorly explored. In this study, we performed a series of in vitro experiments evaluating whether leptospires induce human platelet aggregation, activation, and morphological changes. Platelets were incubated with virulent L. interrogans and the platelet outcomes were assessed by aggregometry, flow cytometry, and scanning and transmission electron microscopy. Our results show that leptospires alone do not induce platelet aggregation and activation, and induce platelet cytotoxic effects instead, by clearly inducing platelet disruption and detachment. We show for the first time that virulent leptospires do interact directly with platelets, an event that could trigger pathophysiological effects during the infection. This study might serve as a basis for the development of novel treatments for the disease.

ESSENTIAL THROMBOCYTOSIS IS THE INTERSECTION OF HEMATOLOGY AND CARDIOLOGY. Review

Relevance. Essential thrombocytosis (ET) is a pathology of clonal hematopoietic stem cells, which is manifested by increased platelet formation. This pathology is quite rare and refers to myeloproliferative diseases. It is more common for women in two age groups: 50-70 y.o. and 20-30 y.o.&#x0D; Objective. Evaluate diagnostic criteria, determine the risk of complications and, depending on this, a treatment plan for essential thrombocytosis.&#x0D; Methods. Analysis of scientific publications in PubMed by keywords for the period 2006-2020. Case Comparison.&#x0D; Results. The article discusses the pathogenesis, clinical picture, diagnostic criteria, determining the risk of complications and, depending on this, the treatment plan. ET is characterized with an increase in the number of megakaryocytes (MGKC) in the bone marrow (BM) and morphological changes in platelets, resulting in functional impairment of the latter. ET has long asymptomatic period. Manifestations of the disease are opposite: thrombosis and bleeding. Among multiple vessels that can be impaired, thrombosis of coronary arteries with a myocardial infarction development occurs in 5,3-12% of patients. In this clinical case patients have to be treated according to the guidelines of management of acute coronary syndrome, however they also have to start pathogenetic treatment. The article provides a clinical example illustrating the need for early pre-asymptomatic diagnosis of ET. In this clinical case, modern algorithms for the diagnosis and treatment of such complications of ET as myocardial infarction are considered.&#x0D; Conclusions. From the above we can conclude that early asymptomatic diagnosis of ET is needed for stratification of the risk of thromboembolic complications according to new recommendations with timely startetd pathogenetic therapy.

Arsenic induces platelet shape change through altering focal adhesion kinase-mediated actin dynamics, contributing to increased platelet reactivity

Arsenic, an environmental contaminant in drinking water worldwide is well-established to increase cardiovascular diseases (CVDs) in humans. Of these, thrombotic events represent a major adverse effect associated with arsenic exposure, for which an abundance of epidemiological evidence exists. Platelet aggregation constitutes a pivotal step in thrombosis but arsenic alone doesn't induce aggregation and the mechanism underlying arsenic-induced thrombosis still remains unclear. Here we demonstrated that arsenic induces morphological changes of platelets, i.e., contraction and pseudopod projection, the primal events of platelet activation, which can increase platelet reactivity. Arsenite induced prominent platelet shape changes in a dose-dependent manner in freshly isolated human platelets. Of note, arsenite suppressed focal adhesion kinase (FAK) activity, which in turn activated RhoA, leading to altered actin assembly through LIMK activation, and subsequent cofilin inactivation. Arsenic-induced platelet shape change appeared to increase the sensitivity to thrombin and ADP-induced aggregation. Supporting this, latrunculin A, an inhibitor of actin-dynamics abolished it. Taken together, we demonstrated that arsenic induces cytoskeletal changes and shape changes of platelets through FAK-mediated alteration of actin dynamics, which renders platelets reactive to activating stimuli, ultimately contributing to increased thrombosis.

Platelet lamellipodium formation is not required for thrombus formation and stability

AbstractDuring platelet spreading, the actin cytoskeleton undergoes rapid rearrangement, forming filopodia and lamellipodia. Controversial data have been published on the role of lamellipodia in thrombus formation and stability. The Wiskott-Aldrich syndrome protein-family verprolin-homologous protein (WAVE)-regulatory complex, which has been shown in other cells to drive lamellipodium formation by enhancing actin nucleation via the actin-related protein 2/3 (Arp2/3) complex, is activated by Ras-related C3 botulinum toxin substrate 1 (Rac1) interaction with the WAVE complex subunit cytoplasmic fragile X mental retardation 1–interacting protein 1 (Cyfip1). We analyzed Cyfip1flox/floxPf4-Cre mice to investigate the role of Cyfip1 in platelet function. These mice displayed normal platelet counts and a slight reduction in platelet volume. Activation of mutant platelets was only moderately reduced to all tested agonists as measured by αIIbβ3 integrin activation and P-selectin surface exposure. However, lamellipodium formation of mutant platelets was completely abolished on different matrices. Nevertheless, Cyfip1-deficient platelets formed stable thrombi on collagen fibers ex vivo and in 2 models of occlusive arterial thrombosis in vivo. Similarly, the hemostatic function and maintenance of vascular integrity during inflammation of the skin and lung were unaltered in the mutant mice. Investigation of platelet morphology in an induced thrombus under flow revealed that platelets rather form filopodia in the thrombus shell, and are flattened with filopodium-like structures when in direct contact to collagen fibers at the bottom of the thrombus. We provide for the first time direct evidence that platelet lamellipodium formation is not required for stable thrombus formation, and that morphological changes of platelets differ between a static spreading assay and thrombus formation under flow.

In systemic lupus erythematosus anti-dsDNA antibodies can promote thrombosis through direct platelet activation

Systemic lupus erythematosus (SLE) is associated with a high risk of venous and arterial thrombosis, not necessarily associated with prothrombotic antiphospholipid antibodies (Abs). Alternatively, thrombosis may be due to an increased titer of anti-dsDNA Abs that presumably promote thrombosis via direct platelet activation. Here, we investigated effects of purified anti-dsDNA Abs from the blood of SLE patients, alone or in a complex with dsDNA, on isolated normal human platelets. We showed that anti-dsDNA Abs and anti-dsDNA Ab/dsDNA complexes induced strong platelet activation assessed by enhanced P-selectin expression and dramatic morphological and ultrastructural changes. Electron microscopy revealed a significantly higher percentage of platelets that lost their discoid shape, formed multiple filopodia and had a shrunken body when treated with anti-dsDNA Abs or anti-dsDNA Ab/dsDNA complexes compared with control samples. In addition, these platelets activated with anti-dsDNA Ab/dsDNA complexes typically contained a reduced number of secretory α-granules that grouped in the middle and often merged into a solid electron dense area. Many activated platelets released plasma membrane-derived microvesicles and/or fell apart into subcellular cytoplasmic fragments. Confocal microscopy revealed that platelets treated with anti-dsDNA Ab/dsDNA complex had a heterogeneous distribution of septin2 compared with the homogeneous distribution in control platelets. Structural perturbations were concomitant with mitochondrial depolarization and a decreased content of platelet ATP, indicating energetic exhaustion. Most of the biochemical and morphological changes in platelets induced by anti-dsDNA Abs and anti-dsDNA Ab/dsDNA complexes were prevented by pre-treatment with a monoclonal mAb against FcγRIIA. The aggregate of data indicates that anti-dsDNA Abs alone or in a complex with dsDNA strongly affect platelets via the FcγRIIA receptor. The immune activation of platelets with antinuclear Abs may comprise a prothrombotic mechanism underlying a high risk of thrombotic complications in patients with SLE.

Tubulin in Platelets: When the Shape Matters.

Platelets are anuclear cells with a short lifespan that play an essential role in many pathophysiological processes, including haemostasis, inflammation, infection, vascular integrity, and metastasis. Billions of platelets are produced daily from megakaryocytes (platelet precursors). Despite this high production, the number of circulating platelets is stable and, under resting conditions, they maintain their typical discoid shape thanks to cytoskeleton proteins. The activation of platelets is associated with dynamic and rapid changes in the cytoskeleton. Two cytoskeletal polymer systems exist in megakaryocytes and platelets: actin filaments and microtubules, based on actin, and α- and β-tubulin heterodimers, respectively. Herein, we will focus on platelet-specific tubulins and their alterations and role of the microtubules skeleton in platelet formation (thrombopoiesis). During this process, microtubules mediate elongation of the megakaryocyte extensions (proplatelet) and granule trafficking from megakaryocytes to nascent platelets. In platelets, microtubules form a subcortical ring, the so-called marginal band, which confers the typical platelet discoid shape and is also responsible for changes in platelet morphology upon activation. Molecular alterations in the gene encoding β1 tubulin and microtubules post-translational modifications may result in quantitative or qualitative changes in tubulin, leading to altered cytoskeleton reorganization that may induce changes in the platelet number (thrombocytopenia), morphology or function. Consequently, β1-tubulin modifications may participate in pathological and physiological processes, such as development.

THE DIFFERENCES VALUE OF P-LCR, THE Î’-THROMBOGLOBULIN LEVEL, THE FIBRIN DEGRADATION PRODUCTS LEVEL IN PRE AND POST-HEMODIALYSIS

Hemostasis disorders in End Stage Renal Disease (ESRD) might be due to uremia syndrome which causing platelet dysfunction. This condition was worsened by chronic hemodialysis which affected the biologic compound degranulation of thrombogenic β-thromboglobulin causing morphological changes of platelets which could be evaluated by using the value of Platelet Large Cell Ratio (P-LCR) and triggering fibrinolysis hyperactivation which increased the Fibrin Degradation Products (FDP) level. The sequence of this mechanism happened continuously. The platelet index evaluation could decide the prognosis after hemodialysis, in addition to monitoring creatinine levels. This study aimed to prove the difference between P-LCR, β-thromboglobulin level, FDP level and creatinine level between pre and post-hemodialysis. The design of this study was observational analytical. Forty-five samples were examined by complete blood count examination using flowcytometry method, the level of β-TG examination by ELISA method, the level of FDP examination by the immunoturbidimetric method and the level of creatinine examination by enzymatic method. The statistical analysis used the Wilcoxon test. It was found that the value of P-LCR in ESRD pre-hemodialysis was higher than in post-hemodialysis with the median 26.8 fl and 25.4 fl, the β- thromboglobulin level increased inpost-hemodialysis compared to pre-hemodialysis (median 200.88 pg/mL and 313.48pg/mL), the FDP level was higher in post-hemodialysis compared to pre-hemodialysis, (median 1.15 µg/mL and 1.7µg/mL), the creatinine level was lower in post-hemodialysis compared to pre-hemodialysis, (median 13.04 mg/dL and 4.56 mg/dL). Therefore, the statistical value was p&lt;0.01. There were significant differences in P-LCR-value, β-thromboglobulin level, fibrin degradation products level and creatinine level between pre and post-hemodialysis.

Morphological Changes of Platelets as a Marker of Early Progression of Diabetic Nephropathy

Aim: To study the main morphological changes of platelets in patients with type 1 diabetes mellitus (T1DM) depending on the level of estimated glomerular filtration rate (eGFR). Materials and Methods: The study involved 37 patients with T1DM. Patients were divided to groups according to the level of eGFR (CKD-EPI, ml/min/1.73m²). Group 1 had eGFR ≥90; group 2 - eGFR 89-60; group 3 - eGFR 59-45. Control group consists of 10 healthy people. All patients were comparable for age and sex. The relative content of unactivated, aggregated, degranulated platelets and the density of packaging of α-granules in the platelet were determined using a transmission electron microscope120kV TEMs (JEOL USA). Results: Changes were found in all three groups compared to the control. Decrease of unactivated platelets (%) 69.7 (62.4; 77), 64.6 (55.5, 73.7), 47.8 (39.6, 56.0), 75.5 (66.2; 84.8), respectively; increase of aggregated platelets (%) 7.4 (6.58; 8.22), 10.6 (9.4; 11.8), 15.4 (14.3; 16.5), 6.8 (5.98; 7.62), respectively; increase of degranulated platelets (%) 7.2 (6.22; 8.18), 10.4 (9.53; 11.27), 21.0 (18.88; 22.12), 6.3 (5.2; 7.4), respectively; decrease of the density of packaging of α-granules in the platelet (mkm³/mkm³) 0.0962 (0.0632; 0.0994); 0.093 (0.06; 0.126), 0.067 (0.038; 0.096), 0.1(0.077; 0.139), respectively. In the study group revealed a direct correlation between eGFR and: unactivated platelets (ρ=0.77; p&amp;lt;0.001), density packing of α-granules (ρ=0.55; p &amp;lt;0.001); the inverse correlation between eGFR and: aggregated platelets (ρ=-0.63; p&amp;lt;0.001), degranulated platelets (ρ=-0.72; p&amp;lt;0.001). Conclusions: Morphological substrate of platelets damage is a complex of ultrastructural changes, which is an early predictor of the development of vascular complications. Morphological changes of platelets are detected with stored eGFR. Stronger changes correspond to low eGFR, that gives us to consider a complex of ultrastructural platelets changes, as an early sign of diabetic nephropathy. Disclosure N. Pertseva: None. C. Daria: None. T. Igor: None.