The platelet-mitochondria nexus in autoimmune and musculoskeletal diseases.

Platelets are crucial for thrombosis and hemostasis. Importantly, they contain mitochondria that are responsible for energy generation and therefore vital for platelet survival and activation. Activated platelets can release mitochondria that may be free or encapsulated in platelet extracellular vesicles (EVs). Extruded mitochondria are a well-known source of mitochondrial DNA, and mitochondrial antigens that can be targeted by autoantibodies forming immune complexes (IC). Interaction of IC with the platelet cell surface FcγRIIA receptor results in platelet activation and release of platelet granule components. In this review, we summarize how platelets and mitochondria may contribute to the pathogenesis of different autoimmune and musculoskeletal diseases. Targeting key drivers of mitochondrial extrusion may ultimately lead to urgently needed targeted pharmacological interventions for treating inflammation and thrombotic diathesis, and halting organ damage in some of these rheumatological conditions.

Liquid biopsy: paving a new avenue for cancer research.

The current constraints associated with cancer diagnosis and molecular profiling, which rely on invasive tissue biopsies or clinical imaging, have spurred the emergence of the liquid biopsy field. Liquid biopsy involves the extraction of circulating tumor cells (CTCs), circulating free or circulating tumor DNA (cfDNA or ctDNA), circulating cell-free RNA (cfRNA), extracellular vesicles (EVs), and tumor-educated platelets (TEPs) from bodily fluid samples. Subsequently, these components undergo molecular characterization to identify biomarkers that are critical for early cancer detection, prognosis, therapeutic assessment, and post-treatment monitoring. These innovative biosources exhibit characteristics analogous to those of the primary tumor from which they originate or interact. This review comprehensively explores the diverse technologies and methodologies employed for processing these biosources, along with their principal clinical applications.

Development of a large diameter in vitro flow loop thrombogenicity test system.

BACKGROUND: To accommodate a wider range of medical device sizes, a larger in vitro flow loop thrombogenicity test system using 9.5 -mm inner diameter (ID) tubing was developed and evaluated based on our previously established 6.4 -mm ID tubing system. METHODS: Four cardiopulmonary bypass roller pumps were used concurrently to drive four flow loops during testing. To ensure that each pump produced a consistent thrombogenic response for the same material under the same test conditions, a novel dynamic roller occlusion setting method was applied. Five materials with varying thrombogenic potentials were tested: polytetrafluoroethylene (PTFE), silicone, 3D-printed nylon, latex, and nitrile rubber (BUNA). Day-old bovine blood was heparinized to a donor-specific concentration and recirculated through the flow loops containing test materials at 20 rpm for 1 h at room temperature. Material thrombogenicity was characterized by measuring the thrombus surface coverage, thrombus weight, and platelet (PLT) count reduction. RESULTS: The larger tubing system can differentiate thrombogenic materials (latex, BUNA) from the thromboresistant PTFE material. Additionally, silicone and the 3D-printed nylon exhibited an intermediate thrombogenic response with significantly less thrombus surface coverage and PLT count reduction than latex and BUNA but more thrombus surface coverage than PTFE (p < 0.05). CONCLUSION: The 9.5 -mm ID test system can effectively differentiate materials of varying thrombogenic potentials when appropriate pump occlusion settings and donor-specific anticoagulation are used. This system is being assessed in an interlaboratory study to develop standardized best practices for performing in vitro dynamic thrombogenicity testing of medical devices and materials.

Early prediction of platelet recovery with immature platelet fraction in patients receiving hematopoietic stem cell transplantation.

Hematopoietic stem cell transplantation (HSCT) is pivotal in treating hematologic disorders, yet it poses the risk of post-transplantation pancytopenia. Prophylactic platelet transfusions are often administered to mitigate this risk. Utilizing practical markers, such as immature platelet fraction (IPF), to predict hematopoietic recovery in advance could reduce unnecessary prophylactic transfusions. Our prospective study, involving 53 HSCT patients at Taipei Veterans General Hospital between September 2022 and May 2023, utilized the Sysmex XN analyzer to assess peripheral blood cell parameters. We investigated whether IPF could predict platelet recovery early, determined the optimal cut-off value, and compared platelet usage. Neutrophil and platelet engraftment occurred 10 (median; range: 10-12) and 15 (median; range: 15-18) days post-HSCT. Notably, 71.7% of patients exhibited an IPF increase exceeding 2% before platelet recovery. The optimal cut-off IPF on day 10 for predicting platelet recovery within five days was 2.15% (specificity 0.89, sensitivity 0.65). On average, patients received 3.89 units of post-transplantation platelet transfusion. Our results indicate that IPF serves as a predictive marker for platelet engraftment, peaking before the increase in platelet count. This insight aids clinicians in assessing the need for prophylactic platelet transfusions. Integrating reference IPF values alongside platelet counts enhances the accuracy of evaluating a patient's hematopoietic recovery status. Anticipating the timing of platelet recovery optimizes blood product usage and mitigates transfusion reaction risks.

Somatic RAP1B gain-of-function variant underlies isolated thrombocytopenia and immunodeficiency.

The ubiquitously expressed small GTPase Ras-related protein 1B (RAP1B) acts as a molecular switch that regulates cell signaling, cytoskeletal remodeling, and cell trafficking and activates integrins in platelets and lymphocytes. The residue G12 in the P-loop is required for the RAP1B-GTPase conformational switch. Heterozygous germline RAP1B variants have been described in patients with syndromic thrombocytopenia. However, the causality and pathophysiological impact remained unexplored. We report a boy with neonatal thrombocytopenia, combined immunodeficiency, neutropenia, and monocytopenia caused by a heterozygous de novo single nucleotide substitution, c.35G>A (p.G12E) in RAP1B. We demonstrate that G12E and the previously described G12V and G60R were gain-of-function variants that increased RAP1B activation, talin recruitment, and integrin activation, thereby modifying late responses such as platelet activation, T cell proliferation, and migration. We show that in our patient, G12E was a somatic variant whose allele frequency decreased over time in the peripheral immune compartment, but remained stable in bone marrow cells, suggesting a differential effect in distinct cell populations. Allogeneic hematopoietic stem cell transplantation fully restored the patient's hemato-immunological phenotype. Our findings define monoallelic RAP1B gain-of-function variants as a cause for constitutive immunodeficiency and thrombocytopenia. The phenotypic spectrum ranged from isolated hematological manifestations in our patient with somatic mosaicism to complex syndromic features in patients with reported germline RAP1B variants.

GP VI-Mediated Platelet Activation and Procoagulant Activity Aggravate Inflammation and Aortic Wall Remodeling in Abdominal Aortic Aneurysm.

BACKGROUND: Platelets play an important role in cardiovascular and cerebrovascular diseases. Abdominal aortic aneurysm (AAA) is a highly lethal, atherosclerosis-related disease with characteristic features of progressive dilatation of the abdominal aorta and degradation of the vessel wall, accompanied by chronic inflammation. Platelet activation and procoagulant activity play a decisive role in the AAA pathology as they might trigger AAA development in both mice and humans. METHODS: The present study investigated the impact of the major platelet collagen receptor GP (platelet glycoprotein) VI in pathophysiological processes underlying AAA initiation and progression. For experimental AAA induction in mice, PPE (porcine pancreatic elastase) and the external PPE model were used. RESULTS: Genetic deletion of GP VI offered protection of mice against aortic diameter expansion in experimental AAA. Mechanistically, GP VI deficiency resulted in decreased inflammation with reduced infiltration of neutrophils and platelets into the aortic wall. Furthermore, remodeling of the aortic wall was improved in the absence of GP VI, as indicated by reduced MMP (matrix metalloproteinase)-2/9 and OPN (osteopontin) plasma levels and an enhanced α-SMA (α-smooth muscle actin) content within the aortic wall, accompanied by reduced cell apoptosis. Consequently, an elevation in intima/media thickness and elastin content was observed in GP VI-deficient PPE mice, resulting in a significantly reduced aortic diameter expansion and reduced aneurysm incidence. In patients with AAA, enhanced plasma levels of soluble GP VI and fibrin, as well as fibrin accumulation within the intraluminal thrombus might serve as new biomarkers to detect AAA early. Moreover, we hypothesize that GP VI might play a role in procoagulant activity and thrombus stabilization via binding to fibrin. CONCLUSIONS: In conclusion, our results emphasize the potential need for a GP VI-targeted antiplatelet therapy to reduce AAA initiation and progression, as well as to protect patients with AAA from aortic rupture.

Impact of duration of dual anti-platelet therapy on risk of complications after stent-assisted coiling of unruptured aneurysms.

BACKGROUND: The optimal duration for dual antiplatelet therapy (DAPT) after stent-assisted coiling (SAC) of intracranial aneurysms is unclear. Longer-term therapy may reduce thrombotic complications but increase the risk of bleeding complications. METHODS: A retrospective review of prospectively maintained data at 12 institutions was conducted on patients with unruptured intracranial aneurysms who underwent SAC between January 1, 2016 and December 31, 2020, and were followed ≥6 months postprocedure. The type and duration of DAPT, stent(s) used, outcome, length of follow-up, complication rates, and incidence of significant in-stent stenosis (ISS) were collected. RESULTS: Of 556 patients reviewed, 450 met all inclusion criteria. Nine patients treated with DAPT <29 days after SAC and 11 treated for 43-89 days were excluded from the final analysis as none completed their prescribed duration of treatment. Eighty patients received short-term DAPT. There were no significant differences in the rate of thrombotic complications during predefined periods of risk in the short, medium, or long-term treatment groups (1/80, 1.3%; 2/188, 1.1%; and 0/162, 0%, respectively). Similarly, no differences were found in the rate of hemorrhagic complications during period of risk in any group (0/80, 0%; 3/188, 1.6%; and 1/162, 0.6%, respectively). Longer duration DAPT did not reduce ISS risk in any group. CONCLUSIONS: Continuing DAPT >42 days after SAC did not reduce the risk of thrombotic complications or in-stent stenosis, although the risk of additional hemorrhagic complications remained low. It may be reasonable to discontinue DAPT after 42 days following non-flow diverting SAC of unruptured intracranial aneurysms.

Endothelial Protein Disulphide Isomerase-A1 enhances membrane stiffness and platelet-endothelium interaction in hyperglycaemia via SLC3A2 and LAMC1.

BACKGROUND: Diabetes carries an increased risk of cardiovascular disease and thromboembolic events. Upon endothelial dysfunction, platelets bind to endothelial cells to precipitate thrombus formation, however, it is unclear which surface proteins regulate platelet-endothelium interaction. We and others have shown that peri/epicellular (pec) protein disulphide isomerase A1 (pecPDI) influences the adhesion and migration of vascular cells. OBJECTIVES: We investigated whether pecPDI regulates adhesion-related molecules on the surface of endothelial cells and platelets that influence the binding of these cells in hyperglycaemia. METHODS: Immunofluorescence was used to assess platelet-endothelium interaction in vitro, cytoskeleton reorganization and focal adhesions. Hydrogen peroxide production was assessed via Amplex Red assays. Cell biophysics was assessed using atomic force microscopy. Secreted proteins of interest were identified through proteomics (secretomics) and targets were knocked down using siRNA. PDI contribution was assessed using whole-cell PDI or pecPDI inhibitors or siRNA. RESULTS: Platelets of healthy donors adhered more onto hyperglycaemic HUVECs. Endothelial, but not platelet, pecPDI regulated this effect. Hyperglycaemic HUVECs showed marked cytoskeleton reorganization, increased H2O2 production and elongated focal adhesions. Indeed, hyperglycaemic HUVECs were stiffer compared to normoglycaemic cells. PDI and pecPDI inhibition reversed the abovementioned processes in hyperglycaemic cells. A secretomics analysis revealed eight proteins secreted in a PDI-dependent manner by hyperglycaemic cells. Among these, we showed that genetic deletion of LAMC1 and SLC3A2 decreased platelet-endothelium interaction and did not potentiate the effects of PDI inhibitors. CONCLUSIONS: Endothelial pecPDI regulates platelet-endothelium interaction in hyperglycemia through adhesion-related proteins and alterations in endothelial membrane biophysics.

Analysis of the expression of cytokines and chemokines, platelet-leukocyte aggregates, sCD40L and sCD62P in cutaneous melanoma.

BACKGROUND: Cutaneous melanoma (CM) is a malignancy with a variable incidence worldwide and a poor advanced-stage prognosis. Melanoma growth is closely associated with the immune system. METHODS: A cross-sectional study was performed on CM patients admitted at the Hospital de Cancer de Pernambuco (HCP) between 2015 and 2018. Fifty-one CM patients were included, and 30 healthy individuals. The study aimed to evaluate the association of platelet activation mechanisms and inflammatory response in patients with cutaneous melanoma. RESULTS: Elevated serum IL10 and low serum TNF levels in CM patients compared to controls (p < 0.05). High IL6 levels in patients with negative lymph nodes LN (-) compared to positive lymph nodes group (LN +, p = 0.0005). Low RANTES levels in patients compared to controls (p < 0.05). Elevated levels of platelet-lymphocyte (PLA), platelet-monocytes (PMA), and platelet-neutrophils (PNA) aggregates were observed in patients compared to controls (p < 0.05). CM patients with stage II had lower PMA levels than stages I and III (p < 0.05). High PMA levels were observed in patients with LN (+) compared to the LN (-) group (p < 0.0001). Patients with SSM had high levels of sCD40L and sCD62P compared to controls (p < 0.05)). High sCD40L levels in stage II compared to the stage III group, and sCD62P in stages I and II compared to the stage III group (p < 0.05). High sCD62P levels in patients with LN (-) compared to the group LN (+) (p < 0.05). CONCLUSION: It was observed the immunosuppressive profile in CM may favor tumor progression. High levels of platelet-leukocyte aggregates, sCD40L, and sCD62P may be associated with the worst prognosis.

Infection versus disease activity in systemic lupus erythematosus patients with fever.

BACKGROUND: to detect the role of procalcitonin, erythrocyte sedimentation rate to c-reactive protein (ESR/CRP) ratio, neutrophils-to-lymphocyte ratio (NLR), and platelets-to-lymphocyte ratio (PLR) in the diagnosis of infection in systemic lupus erythematosus (SLE) patients with fever, their diagnostic value to differentiate between infection and disease activity, and their correlation with disease activity. METHODS: Forty SLE patients and forty healthy control cases were included in the study. Disease activity was assessed by the Systemic Lupus Erythematosus Disease Activity Index 2000 (SLEDAI-2 K), and quality of life was assessed by Lupus QoL. A bacterial infection was detected by clinical symptoms and positive culture results. Laboratory tests were done for all patients and controls: complete blood count (CBC), ESR, CRP, and procalcitonin (PCT). NLR, PLR, and ESR/CRP ratios were calculated. RESULTS: There was a statistically significant difference between infected SLE patients and non-infected SLE patients regarding PCT (p < 0.001), ESR (p = 0.002), CRP (p = 0.005), ESR/CRP ratio (0.002), and NLR (p = 0.023). PCT, ESR, CRP, and NLR were positively correlated with the presence of infection in SLE patients, while the ESR/CRP ratio was negatively correlated. There was no significant correlation with the SLEDAI-2 K score. Logistic regression analysis revealed that PCT was the best significant predictor of infection (OR 224.37, 95% CI 8.94-5631.35). PCT was a good predictor of infection, with a cut-off value of 0.90 ng/ml, which gave the best combination of sensitivity (84.62%) and specificity (85.71%). CONCLUSION: PCT, ESR/CRP ratio, and NLR provide good diagnostic markers for the diagnosis of infection and can distinguish between infection and disease flare in SLE patients with fever.

Biofilm-dispersed pneumococci induce elevated leukocyte and platelet activation.

Introduction: Streptococcus pneumoniae (the pneumococcus) effectively colonizes the human nasopharynx, but can migrate to other host sites, causing infections such as pneumonia and sepsis. Previous studies indicate that pneumococci grown as biofilms have phenotypes of bacteria associated with colonization whereas bacteria released from biofilms in response to changes in the local environment (i.e., dispersed bacteria) represent populations with phenotypes associated with disease. How these niche-adapted populations interact with immune cells upon reaching the vascular compartment has not previously been studied. Here, we investigated neutrophil, monocyte, and platelet activation using ex vivo stimulation of whole blood and platelet-rich plasma with pneumococcal populations representing distinct stages of the infectious process (biofilm bacteria and dispersed bacteria) as well as conventional broth-grown culture (planktonic bacteria). Methods: Flow cytometry and ELISA were used to assess surface and soluble activation markers for neutrophil and monocyte activation, platelet-neutrophil complex and platelet-monocyte complex formation, and platelet activation and responsiveness. Results: Overall, we found that biofilm-derived bacteria (biofilm bacteria and dispersed bacteria) induced significant activation of neutrophils, monocytes, and platelets. In contrast, little to no activation was induced by planktonic bacteria. Platelets remained functional after stimulation with bacterial populations and the degree of responsiveness was inversely related to initial activation. Bacterial association with immune cells followed a similar pattern as activation. Discussion: Differences in activation of and association with immune cells by biofilm-derived populations could be an important consideration for other pathogens that have a biofilm state. Gaining insight into how these bacterial populations interact with the host immune response may reveal immunomodulatory targets to interfere with disease development.

The CALR mutations enhance the expression of the immunosuppressive proteins GARP and LAP on peripheral blood lymphocytes through increased binding of activated platelets.

Recently, an antibody which inhibits the glycoprotein A repetitions predominant (GARP)-mediated release of active transforming growth factor beta (TGFß) from the TGFß propeptide latency-associated peptide (LAP) showed preclinical activity in a murine model of the chronic myeloproliferative neoplasms (MPN). Consequently, we investigated the expression of the immunosuppressive molecules LAP and GARP on peripheral blood lymphocytes from 56 MPN patients and 11 healthy donors (HD). We found that lymphocytes from patients with MPN express higher levels of LAP and GARP with no strong differences found between the different MPN diagnoses. The impact of clinical parameters on the expression of LAP and GARP by lymphocytes showed that patients with calreticulin (CALR)mut MPN have increased expression compared with HD and patients with the Januskinase2 (JAK2) mutation. The fraction of lymphocytes bound to activated platelets (aPLT) strongly correlate to LAP and GARP expression suggesting that it is not the lymphocytes themselves but aPLT, which confer the increased expression of GARP and LAP on MPN patient lymphocytes. Notably, no differences in neither platelet counts nor anti-thrombotic therapy was identified between patients with JAK2- and CALRmut patients. Analysis of platelet gene expression failed to identify differences in expression of relevant genes between JAK2- and CALRmut patients.

Platelet count as a prognostic marker for acute respiratory distress syndrome.

BACKGROUND: This study aimed to evaluate the role of platelet count (PLT) in the prognosis of patients with acute respiratory distress syndrome (ARDS). METHODS: The data were extracted from the Medical Information Mart for Intensive Care database (version 2.2). Patients diagnosed with ARDS according to criteria from Berlin Definition and had the platelet count (PLT) measured within the first day after intensive care unit admission were analyzed. Based on PLT, ARDS patients were divided into four groups: PLT ≤ 100 × 109/L, PLT 101-200 × 109/L, PLT 201-300 × 109/L, and PLT > 300 × 109/L. The primary outcome was 28-day mortality. Survival probabilities were analyzed using Kaplan-Meier. Furthermore, the association between PLT and mortality in ARDS patients was assessed using a univariate and multivariable Cox proportional hazards model. RESULTS: Overall, the final analysis included 3,207 eligible participants with ARDS. According to the Kaplan-Meier curves for 28-day mortality of PLT, PLT ≤ 100 × 109/L was associated with a higher incidence of mortality (P = 0.001), the same trends were observed in the 60-day (P = 0.001) and 90-day mortality (P = 0.001). In the multivariate model adjusted for the potential factors, the adjusted hazard ratio at PLT 101-200 × 109/L group, PLT 201-300 × 109/L, and PLT > 300 × 109/L was 0.681 [95% confidence interval (CI): 0.576-0.805, P < 0.001], 0.733 (95% CI: 0.604-0.889, P = 0.002), and 0.787 (95% CI: 0.624-0.994, P = 0.044) compared to the reference group (PLT ≤ 100 × 109/L), respectively. Similar relationships between the PLT ≤ 100 × 109/L group and 28-day mortality were obtained in most subgroups. CONCLUSION: PLT appeared to be an independent predictor of mortality in critically ill patients with ARDS.

The growth factor content as an indicator of platelet counts in platelet-rich plasma.

BACKGROUND: Platelet contains growth factors that enhance tissue repair mechanisms, including epidermal growth factor (EGF), platelet-derived growth factor (PDGF-AA and -AB), and transforming growth factor (TGF)-ß. Autologous platelet-rich plasma (PRP) has been shown to significantly improve the treatment of tendon injuries compared with hyaluronic acid and placebo. The topic of agreement between platelet concentrations and growth factors has been covered in some previous studies, but growth factor levels did not correlate well with platelet concentrations. METHOD: In this study, autologous PRP was prepared by concentrating platelets through a J6-MI centrifuge. The automatic hematology analyzer Sysmex XN-20 was used to analyze the platelet concentration in PRP, and the PRP growth factors were determined by ELISA, including PDGF, transforming growth factor- ß1 (TGF-ß1), and EGF. Statistical analysis was conducted on data from 107 patients who received autologous PRP using Pearson correlation analysis. RESULTS: Pearson correlation analysis revealed PDGF, TGF, and EGF had a strong positive correlation with the platelet concentration of the final PRP product (r = 0.697, p < 0.0001; r = 0.488, p < 0.0001; r = 0.572, p < 0.0001, respectively) CONCLUSIONS: There was a strong positive correlation between the concentration of platelets in the final PRP product and the levels of PDGF-AB, TGF-ß, and EGF. These results suggested straightforward and cost-effective growth factor tests can provide valuable information about platelet content in PRP.

Differential effects of physiological agonists on the proteome of platelet-derived extracellular vesicles.

Arterial thrombosis contributes to some of the most frequent causes of mortality globally, such as myocardial infarction and stroke. Platelets are essential mediators of physiological haemostasis and pathological thrombosis. Platelet activation is controlled by a multitude of signalling pathways. Upon activation, platelets shed platelet-derived extracellular vesicles (pEVs). In this Special Issue: Extracellular Vesicles, Moon et al. investigate the impact of various platelet agonists (thrombin, ADP, collagen) on the proteome of pEVs. The study demonstrates that pEVs exhibit an agonist-dependent altered proteome compared to their parent cells, with significant variations in proteins related to coagulation, complement, and platelet activation. The study observes the rapid generation of pEVs following agonist stimulation with specific proteome alterations that underscore an active packaging process. This commentary highlights the implications of their findings and discusses the role of pEV cargo in cardiovascular disease with potential novel therapeutic and diagnostic opportunities.

Filamin A regulates platelet shape change and contractile force generation via phosphorylation of the myosin light chain.

Platelets are critical mediators of hemostasis and thrombosis. Platelets circulate as discs in their resting form but change shape rapidly upon activation by vascular damage and/or soluble agonists such as thrombin. Platelet shape change is driven by a dynamic remodeling of the actin cytoskeleton. Actin filaments interact with the protein myosin, which is phosphorylated on the myosin light chain (MLC) upon platelet activation. Actin-myosin interactions trigger contraction of the actin cytoskeleton, which drives platelet spreading and contractile force generation. Filamin A (FLNA) is an actin-crosslinking protein that stabilizes the attachment between subcortical actin filaments and the cell membrane. In addition, FLNA binds multiple proteins and serves as a critical intracellular signaling scaffold. Here, we used platelets from mice with a megakaryocyte/platelet-specific deletion of FLNA to investigate the role of FLNA in regulating platelet shape change. Relative to controls, FLNA-null platelets exhibited defects in stress fiber formation, contractile force generation, and MLC phosphorylation in response to thrombin stimulation. Blockade of Rho kinase (ROCK) and protein kinase C (PKC) with the inhibitors Y27632 and bisindolylmaleimide (BIM), respectively, also attenuated MLC phosphorylation; our data further indicate that ROCK and PKC promote MLC phosphorylation through independent pathways. Notably, the activity of both ROCK and PKC was diminished in the FLNA-deficient platelets. We conclude that FLNA regulates thrombin-induced MLC phosphorylation and platelet contraction, in a ROCK- and PKC-dependent manner.

Clopidogrel-Mediated P2Y12 Inhibition According to Renal Function in Patients With Diabetes Mellitus and CAD.

This prospective ex vivo and in vitro pharmacodynamic (PD)/pharmacokinetic investigation was conducted in patients with diabetes mellitus with (n = 31) and without chronic kidney disease (n = 30). PD assessments included platelet reactivity index, maximum platelet aggregation, and P2Y12 reaction units. Ex vivo pharmacokinetic assessments included plasma levels of clopidogrel and its active metabolite. In vitro PD assessments were conducted on baseline samples incubated with escalating concentrations of clopidogrel and its active metabolite. Among patients with diabetes mellitus treated with clopidogrel, impaired renal function was associated with increased maximum platelet aggregation. This finding could be attributed partially to upregulation of the P2Y12 activity without differences in drug absorption or metabolism. (Impact of Chronic Kidney Disease on Clopidogrel Effects in Diabetes Mellitus; NCT03774394).

Glycopolymeric Micellar Nanoparticles for Platelet-Mediated Tumor-Targeted Delivery of Docetaxel for Cancer Therapy.

The high level of accumulation of therapeutic agents in tumors is crucial for cancer treatment. Compared to the passive tumor-targeting effect, active tumor-targeting delivery systems, primarily mediated by peptides with high production costs and reduced circulation time, are highly desired. Platelet-driven technologies have opened new avenues for targeted drug delivery prevalently through a membrane coating strategy that involves intricate manufacturing procedures or the fucoidan-mediated hitchhiking method with limited platelet affinity. Here, a novel type of amphiphilic glycopolymer self-assembled micellar nanoparticle has been developed to adhere to naturally activated platelets in the blood. The simultaneous integration of fucose and sialic acid segments into glycopolymers enables closer mimicry of the structure of P-selectin glycoprotein ligand-1 (PSGL-1), thereby increasing the affinity for activated platelets. It results in the formation of glycopolymeric micelle-platelet hybrids, facilitating targeted drug delivery to tumors. The selective platelet-assisted cellular uptake of docetaxel (DTX)-loaded glycopolymeric micelles leads to lower IC50 values against 4T1 cells than that of free DTX. The directed tumor-targeting effect of activated platelets has significantly improved the tumor accumulation capacity of the glycopolymeric nanoparticles, with up to 21.0% found in tumors within the initial 0.2 h. Additionally, with acid-responsive drug release and inherent antimetastasis properties, the glycopolymeric nanoparticles ensured potent therapeutic efficacy, prolonged survival time, and reduced cardiotoxicity, presenting a new and unexplored strategy for platelet-directed drug delivery to tumors, showing promising prospects in treating localized tumors and preventing tumor metastasis.

Enzymic Activity, Metabolites, and Hematological Responses in High-Risk Newly Received Calves for "Clinical Health" Reference Intervals.

Enzymic activity, metabolites, and hematological responses for reference intervals (RIs) establish ranges of physiological normality, which are useful for diagnosing diseases and physiological alterations. Within the same species, RIs vary according to age, gender, productive and physiological states, and environmental factors including health management and nutrition. RIs have been extensively studied in dairy calves during a critical stage of life (from birth up to first 90 days of age). A critical stage for feedlot calves is their arrival at the feedlot, but no reports determine RIs for different enzymic activity, metabolites, and hematological responses during their initial period at the feedlot. Consequently, a total of 461 high-risk crossbreed beef calves, received on three different dates, were examined upon arrival at the feedlot. Of these, 320 calves (148.3 ± 1.3 kg body weight) whose "clinical health" was evaluated were included in the study. Blood samples were taken upon arrival and on days 14, 28, 42, and 56 to determine the following parameters: enzymic activity, metabolites, electrolytes, white blood cells, platelets, and red blood cells. Enzymic activity, metabolites, and complete blood count were determined by automated analyzers. The freeware Reference Value Advisor Software was used to calculate the non-parametric values of RIs. This study is the first to establish RIs for different enzymic activity, metabolites, and hematological responses in high-risk newly received calves during their initial period at the feedlot. This information will be useful for veterinary clinical practice and research related to the health and welfare of high-risk newly received calves during their initial period at the feedlot.

Inflammation-, immunothrombosis,- and autoimmune-feedback loops may lead to persistent neutrophil self-stimulation in long COVID.

Understanding the pathophysiology of long COVID is one of the most intriguing challenges confronting contemporary medicine. Despite observations recently made in the relevant molecular, cellular, and physiological domains, it is still difficult to say whether the post-acute sequelae of COVID-19 directly correspond to the consequences of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. This work hypothesizes that neutrophils and neutrophil extracellular traps (NETs) production are at the interconnection of three positive feedback loops which are initiated in the acute phase of SARS-CoV-2 infection, and which involve inflammation, immunothrombosis, and autoimmunity. This phenomenon could be favored by the fact that SARS-CoV-2 may directly bind and penetrate neutrophils. The ensuing strong neutrophil stimulation leads to a progressive amplification of an exacerbated and uncontrolled NETs production, potentially persisting for months beyond the acute phase of infection. This continuous self-stimulation of neutrophils leads, in turn, to systemic inflammation, micro-thromboses, and the production of autoantibodies, whose significant consequences include the persistence of endothelial and multiorgan damage, and vascular complications.