Evaluation of soluble P-selectin as a predictive biomarker in acute symptomatic pulmonary embolism: Insights from a prospective observational study.

BACKGROUND: Soluble P-selectin (sP-selectin) has been proposed as a potential biomarker for venous thromboembolism (VTE) diagnosis with interesting results. However, its role in predicting early mortality in pulmonary embolism (PE) remains unexplored. METHODS: This observational, prospective, single-center study enrolled consecutive patients aged 18 or older with confirmed acute symptomatic PE and no prior anticoagulation. The study aims to assess the prognostic capacity of sP-selectin measured at the time of PE diagnosis for short-term mortality and major bleeding. RESULTS: A total of 196 patients, with a mean age of 69.1 years (SD 17), were included, of whom 52.6% were male. Within 30 days, 9.7% of patients (n = 19) died, and 5.1% (n = 10) suffered major bleeding. PE risk stratification revealed 4.6% (n = 9) with high-risk PE, 34.7% (n = 68) with intermediate-high-risk PE, 38.3% (n = 75) with intermediate-low-risk PE, and 22.5% (n = 44) with low-risk PE according to the European Society of Cardiology score. Mean plasma sP-selectin levels were comparable between survivors and non-survivors (489.7 ng/mL ±63 vs. 497.3 ng/mL ±51; p = .9). The ROC curve for 30-day all-cause mortality and major bleeding yielded an AUC of 0.49 (95% CI 0.36-0.63) and 0.46 (95% CI 0.24-0.68), respectively. Multivariate and survival analyses were precluded due to lack of significance. CONCLUSIONS: sP-selectin was not useful for predicting short-term mortality or major bleeding in patients with acute symptomatic pulmonary embolism. Further studies are required to clarify the role of sP-selectin in VTE, particularly in prognosticating PE outcomes.

Thrombotic Risk Assessment in Patients with Lymphoid Neoplasm seen at the Nnamdi Azikiwe University Teaching Hospital, Nnewi, Anambra State.

BACKGROUND: Venous thromboembolism (VTE) is a cause of increased morbidity and mortality in cancer patients. VTE is the second leading cause of death in cancer patients. Risk assessment models have been developed to identify patients at risk of VTE for thromboprophylaxis. Risk scores of patients in our environment have not been adequately investigated. OBJECTIVE: The study evaluates the association of thrombotic risk assessment scores (using the modified Khorana risk assessment tool) and soluble P-selectin levels with thrombotic events in patients with lymphoid cancer. METHODS: This is a comparative cross-sectional study conducted at Nnamdi Azikiwe University Teaching Hospital (NAUTH, Nnewi, Anambra State). Forty-five patients with lymphoid malignancy and 45 apparently healthy subjects participated in the study. The modified Khorana risk assessment score was used to assess cancer-associated thrombotic risk. Blood sample was collected for soluble P-selectin estimation. Data were analyzed with SPSS version 23. RESULTS: The age of subjects with lymphoid neoplasm and controls were 49.1±15.8 years, and 49.6±11.1 years respectively (p = 0.548). Subjects with lymphoid neoplasm consist of 26 (57.8%) males and 19 (42.2%) females while the controls consist of 25 (55.6%) males and 20 (44.4%) females. Non-Hodgkin's lymphoma was the most frequent of lymphoid neoplasm (18, 40.0%), followed by multiple myeloma (10, 22%), CLL (9, 20%), ALL (6, 13.0%) and Hodgkin's lymphoma (2, 4.0%). Thirty-five (77.8%) subjects with lymphoid neoplasm had intermediate risk scores and 10 (22.2%) had high-risk scores. Nineteen (42.2%) of the controls had intermediate risk and 26 (57.8%) low risk. The differences in proportion were statistically significant (p < 0.001). The median (IQR) levels of soluble P-selectin were significantly higher in patients with lymphoid neoplasm (12.2 vs. 7.0ng/mL, p <0.001). Three (6.6%) patients with lymphoid malignancies had deep vein thrombosis confirmed by a Doppler ultrasound scan. CONCLUSION: Lymphoid malignancy is associated with relatively higher thrombotic risk scores, sP-selectin levels, and venous thromboembolic events. CONTEXTE: La thromboembolie veineuse (TEV) est une cause de morbidité et de mortalité accrues chez les patients atteints de cancer. La TEV est la deuxième cause de décès chez les patients atteints de cancer. Des modèles d'évaluation des risques ont été mis au point pour identifier les patients présentant un risque de TEV en vue d'une thromboprophylaxie. Les scores de risque des patients dans notre environnement n'ont pas été étudiés de manière adéquate. OBJECTIF: L'étude évalue l'association des scores d'évaluation du risque thrombotique (en utilisant l'outil modifié d'évaluation du risque de Khorana) et des niveaux de P-sélectine soluble avec les événements thrombotiques chez les patients atteints d'un cancer lymphoïde. MÉTHODES: Il s'agit d'une étude transversale comparative menée au Nnamdi Azikiwe University Teaching Hospital (NAUTH, Nnewi, État d'Anambra). Quarante-cinq patients atteints d'un cancer lymphoïde et 45 sujets apparemment sains ont participé à l'étude. Le score modifié d'évaluation du risque de Khorana a été utilisé pour évaluer le risque thrombotique associé au cancer. Un échantillon de sang a été prélevé pour l'estimation de la P-sélectine soluble. Les données ont été analysées avec SPSS version 23. RÉSULTATS: L'âge des sujets atteints de néoplasme lymphoïde et des témoins était respectivement de 49,1±15,8 ans et 49,6±11,1 ans (p = 0,548). Les sujets atteints de néoplasme lymphoïde sont 26 (57,8 %) hommes et 19 (42,2 %) femmes, tandis que les témoins sont 25 (55,6 %) hommes et 20 (44,4 %) femmes. Le lymphome non hodgkinien était le néoplasme lymphoïde le plus fréquent (18, 40 %), suivi du myélome multiple (10, 22 %), de la LLC (9, 20 %), de la LAL (6, 13 %) et du lymphome hodgkinien (2, 4 %). Trente-cinq (77,8 %) sujets atteints de néoplasmes lymphoïdes présentaient un score de risque intermédiaire et 10 (22,2 %) un score de risque élevé. Dix-neuf (42,2 %) des témoins présentaient un risque intermédiaire et 26 (57,8 %) un risque faible. Les différences de proportion étaient statistiquement significatives (p < 0,001). Les niveaux médians (IQR) de P-sélectine soluble étaient significativement plus élevés chez les patients atteints de néoplasme lymphoïde (12,2 vs. 7,0 ng/mL, p <0,001). Trois (6,6 %) patients atteints de tumeurs lymphoïdes ont présenté une thrombose veineuse profonde confirmée par une échographie Doppler. CONCLUSION: Les tumeurs malignes lymphoïdes sont associées à des scores de risque thrombotique, des taux de sP-sélectine et des événements thromboemboliques veineux relativement plus élevés. Mots-clés: Malignité lymphoïde, Thrombose, P-sélectine soluble, Scores d'évaluation du risqué.

Association between short-term exposure to ambient air pollution and biomarkers of coagulation: A systematic review and meta-analysis.

Ambient air pollution is one of the major global risk factors for cardiovascular health, and coagulation changes have been proposed to mediate this risk. Plasminogen activator inhibitor-1 (PAI-1), von Willebrand factor (vWF), soluble P-selectin (sP-selectin) and tissue plasminogen activator (t-PA) are major coagulation biomarkers. However, there has been no systematic meta-analysis to summarize associations of ambient air pollution with these coagulation biomarkers. To assess the overall associations between ambient particulate matter (PM2.5, PM10), ozone (O3), nitrogen dioxide (NO2), carbon monoxide (CO) and major coagulation biomarkers including PAI-1, vWF, sP-selectin and t-PA based on the existing epidemiological research. We performed a systematic literature search of publications reporting the associations of ambient air pollutants (PM2.5, PM10, O3, NO2, and CO) with coagulation biomarkers (PAI-1, vWF, sP-selectin and t-PA) in PubMed, Web of Science, EMBASE, and Scopus databases as of April 5, 2022. Then, we performed a random-effect meta-analysis, which included 27 articles, and then identified the potential sources of heterogeneity. The pooled percent changes of coagulation biomarkers per 10 µg/m3 increase in short-term exposure to ambient PM2.5 were 2.43% (95% CI: 0.59%, 4.29%) in PAI-1, 1.08% (95% CI: 0.21%, 1.96%) in vWF and 1.14% (95% CI: 0.59%, 1.68%) in sP-selectin, respectively. We also found significant associations of short-term exposure to ambient O3 with PAI-1 (1.62%, 95% CI: 0.01%, 3.25%), sP-selectin (9.59%, 95% CI:2.78%, 16.86%) and t-PA (0.45%, 95% CI: 0.02%, 0.88%), respectively. Short-term exposures to ambient PM10, NO2 and CO were not significantly associated with changes in coagulation biomarkers. In conclusion, short-term exposures to PM2.5 and O3 are associated with significant increases in coagulation biomarkers, suggesting an activated coagulation state upon air pollution exposure.

Plasma Soluble P-selectin, Interleukin-6 and S100B Protein in Patients with Schizophrenia: a Pilot Study.

Microglial activation has long been posited to be involved in the neurobiology of schizophrenia. However, recent studies indicate that schizophrenia is associated with astrocytic activation, rather than microglia activation. Moreover, elevated levels of peripheral inflammatory cytokines associated with schizophrenia could induce or reflect brain inflammation. Therefore, based on: 1) findings of a periphery-to-brain communication pathway involving the cell adhesion molecule, P-selectin, in animal models; 2) dysregulated interleukin-6 (IL-6) and elevated levels of the astrocytic marker, S100B protein, in patients with schizophrenia, we sought to determine correlations between plasma soluble P-selectin (sP-selectin), S100B and IL-6 respectively. We recruited 106 patients with schizophrenia (mean age 33 years, 71.60% male) from the inpatient. sP-selectin, S100B and IL-6 were measured in fasting plasma. We calculated Pearson's and partial correlations between sP-selectin, S100B and IL-6. After controlling for potential confounders, sP-selectin positively correlated with S100B (r=0.31, p=0.004) and IL-6 (r=0.28, P=0.046). The correlation between IL-6 and S100B (r=0.28, p=0.066) did not reach statistical significance. We propose that in some patients with schizophrenia, immune activation in the periphery is associated with P-selectin-mediated trafficking of inflammation into the brain (most likely via leukocytes), which might be associated with astrocytic activation. Future studies should include healthy controls and first episode/early-onset psychosis patients. Importantly, in vivo imaging of neuroinflammation should be correlated with sP-selectin, IL-6 and S100B in the periphery and the CSF. Finally, the utility of combining sP-selectin, IL-6 and S100B as biomarkers for subtyping patients with schizophrenia, treatment selection and prognosis, should be evaluated in longitudinal studies.

Walking-induced endothelial dysfunction predicts ischemic cardiovascular events in patients with intermittent claudication.

Endothelial dysfunction, evaluated by flow-mediated dilatation (FMD), predicts adverse cardiovascular events in patients with intermittent claudication (IC). IC is an example of repeated ischemia/reperfusion injury that may contribute to the progression of vascular disease by worsening endothelial function, a trigger for acute cardiovascular events. The predictive value of effort-induced endothelial dysfunction for cardiovascular events in patients with IC has not been studied previously. The objective of this study was to assess whether exercise-induced endothelial dysfunction is predictive of adverse cardiovascular outcome in IC. In 44 patients with IC, we measured brachial artery FMD by B-mode ultrasonography at rest and 10 minutes after a maximal treadmill exercise. Treadmill exercise halved the FMD (from 3.5 ± 0.6% to 1.45 ± 0.46%, p < 0.05). After a follow-up period of 85 (72-98) months, a total of 20 major cardiovascular events occurred. In a multivariate analysis, a post-exercise reduction of brachial FMD > 1.3% was predictive for cardiovascular events. Maximal exercise-induced endothelial dysfunction is predictive of cardiovascular events in patients with IC.

Soluble P-selectin levels in patients with obstructive sleep apnea: a systematic review and meta-analysis.

PURPOSE: Obstructive sleep apnea (OSA) patients are at increased risk for cardiovascular disease, stroke, atherosclerosis, hypertension, and venous thromboembolism. Elevated soluble P-selectin (sP-selectin) levels are also associated with increased risk of above diseases. But whether sP-selectin levels in OSA patients are higher than their counterparts remain unclear, since previous studies yielded inconsistent results. Therefore, a meta-analysis is warranted. METHODS: PubMed, Embase, Cochrane Library, and Web of Science databases were searched for eligible studies. Studies were included if they reported sP-selectin levels of both OSA patients and non-OSA controls. Standardized mean differences (SMDs) with 95% confidence intervals (CIs) were calculated to determine the effect sizes. RESULTS: Nine eligible studies were finally evaluated. When all the studies were pooled, sP-selectin levels in OSA patients were significantly higher than that in controls (SMD = 0.54, 95% CI 0.29-0.78, I2 = 66%, p < 0.0001). In the subgroup analysis based on BMI matched groups, sP-selectin levels were significantly higher in OSA patients than that in controls (SMD = 0.52, 95% CI 0.27-0.76, I2 = 23%, p < 0.0001). In the subgroup analysis stratified by blood source, either serum sP-selectin levels or plasma sP-selectin levels in OSA patients were higher than that in controls. Moderate-to-severe OSA patients had significant higher sP-selectin levels (SMD = 0.80, 95% CI 0.45-1.15, I2 = 67%, p < 0.00001), while mild OSA patients showed no significant difference with controls. CONCLUSION: The pooled results reveal that OSA patients have higher sP-selectin levels than non-OSA controls. This conclusion remains unaltered in all subgroups other than the subgroup of mild OSA patients. Additional studies are warranted to better identify the role of sP-selectin as a potential biomarker in OSA patients.

Comparison of diverse platelet activation markers as indicators for left atrial thrombus in atrial fibrillation.

Atrial fibrillation (AF) is well known for being a major risk factor of thromboembolic stroke. We could recently demonstrate an association of monocyte-platelet aggregates (MPAs) with the degree of thrombogenicity in patients with AF. This study investigated platelet activation markers, as potential biomarkers for the presence of left atrial (LA) thrombus in patients with AF. One hundred and eight patients with symptomatic AF underwent transesophageal echocardiography (TEE) before scheduled cardioversion or pulmonary vein isolation. In order to determine the content of MPAs by flow-cytometric quantification analyses, blood was drawn on the day of TEE. The soluble CD40 Ligand (sCD40L) and soluble P-selectin (sP-selectin) were obtained by Cytometric Bead Arrays (CBA). D-dimer levels were detected by quantitative immunological determination of fibrin degradation products. Clinical, laboratory, and echocardiographic standard parameters were obtained from all patients, including the determination of the flow in the left atrial appendage (LAA). Patients with detected LA thrombus (n = 28) compared with patients without thrombus (n = 80) showed an increased number of common risk factors, such as age, diabetes, heart failure, and coronary artery disease (CAD). The presence of LA thrombus was associated with significantly increased levels of MPAs (147 ± 12 vs. 304 ± 29 per µl; p < 0.00), sCD40L (106.3 ± 31.0 vs. 33.5 ± 2.1 pg/ml, p = 0.027), and D-dimer (0.13 ± 0.02 vs. 0.69 ± 0.21 mg FEU/l, p = 0.015). In contrast, sP-selectin showed no association with LA thrombus. A multivariate regression analysis showed that MPAs, sCD40L as well as D-dimers were independent indicators for the existence of LA thrombus. MPAs above 170 cells/µl indicated LA thrombus with a high sensitivity of 93% and a specificity of 73% (OR 62, 95% CI. 6.9-557.2, p < 0.001) in patients with AF, whereas the D-dimer lost their quality as independent indicator by using the conventional cut-off of 0.5 mg/l within the regression analysis. MPAs, as well as the D-dimer, correlated significantly negatively with the flow in the LAA measured during TEE. The content of MPAs, sCD40L, and D-dimer, but not sP-selectin showed an increased dependence on LA thrombus in patients with AF. In our study group, MPAs showed the best diagnostic test accuracy of the compared platelet markers. The different results of the examined platelet activation markers could be an indication of diverse mechanisms of LA thrombus in AF. Further studies should evaluate whether determination of MPAs in clinical routine may suffice to indicate the presence of LA thrombus in patients with AF.

sP- and sE-selectin in stroke patients with metabolic disorders.

BACKGROUND: Activation of platelets and endothelial cells plays an important role in the pathogenesis of atherosclerosis and thrombotic disorders. The aim of our study was to assess the relationship between the metabolic disorders and markers of platelet activity and vascular injury in patient with acute ischemic stroke. MATERIAL AND METHODS: The study group consisted of 84 patients with acute non-lacunar ischemic stroke divided into four subgroups with: (1) normolipidemia and normoglycemia, (2) normolipidemia and hyperglycemia, (3) hyperlipidemia and normoglycemia, (4) hyperlipidemia and hyperglycemia. 21 healthy subjects served as controls. We analyzed the concentration of adhesion molecules sP-selectin and sE-selectin in serum collected from all studied groups using ELISA method. RESULTS: We observed significantly higher sE- and sP-selectin concentration in patients with hyperglycemia and hyperlipidemia compared to both control subjects and patients with normolipidemia and normoglycemia. We did not observe additional effect of comorbid hyperlipidemia and hyperglycemia on studied markers. Soluble E- and P-selectin concentration correlated positively with LDL, TC and HbA1c level in all stroke patients. CONCLUSION: Soluble E- and P-selectin, blood markers of vascular injury and platelet activation, could be useful in the assessment of atherothrombotic properties of hyperglycemia and hyperlipidemia in stroke patients.

Relationship between renal function and circulating microparticles, soluble P-selectin and E-selectin levels in atrial fibrillation.

Atrial fibrillation (AF) and chronic kidney disease are closely related, and any associated risk of stroke and thromboembolism due to AF is increased by concurrent renal dysfunction. The mechanism(s) for this include abnormalities in platelets and endothelial cells. We hypothesized relationships between levels of circulating platelet microparticles (PMPs, defined by CD42b), soluble P selectin (both reflecting platelet activation), soluble E-selectin (reflecting endothelial activation) and endothelial/platelet microparticles (EPMPs, defined by CD31) with progressive renal dysfunction. Blood samples were obtained from 160 anticoagulated AF patients. Microparticles were measured by flow cytometry, soluble E and P selectin levels by ELISA. Renal function was determined by estimated glomerular filtration rate (eGFR). EPMP levels demonstrated a linear increased trend across quartiles of eGFR (p = 0.034) and CKD stage (p < 0.001), and correlated with eGFR and serum creatinine (p < 0.01). PMPs, P-selectin and E-selectin levels were not significantly different across groupings of renal dysfunction, and no significant correlations with eGFR were evident (p = 0.186, p = 0.561, p = 0.746 respectively). Stepwise multivariable regression analysis demonstrated that worsening renal function was an independent predictor of EPMP levels (p < 0.001). In well-anticoagulated AF patients, there is potential relationship between endothelial function (as judged by elevated EPMP levels, with no change in PMPs) and renal function. Other markers of prothombotic state or cellular activation (PMP, P-selectin and E-selectin levels) were not significantly different across the various degree of renal dysfunction. Renal function must be addressed when measuring EPMP levels.

Levels of platelet-derived microparticles and soluble p-selectin in patients of acute myocardial infarction (case control study).

OBJECTIVE: TTo measure levels of platelet-derived microparticles and soluble P-selectin in patients of acute myocardial infarction and their comparison with healthy controls. METHODS: This case-control study was conducted in Department of Haematology, University of Health Sciences Lahore from April to September 2013, and comprised patients of acute myocardial infarction in group 1 and healthy controls in group 2. Platelet-derived microparticles and soluble P-selectin were measured by enzyme-linked immunosorbent assay. SPSS21 was used for data analysis. RESULTS: Of the 80 participants, 50(62.5%) were patients and 30(37.5%) were controls. The mean levels of platelet-derived microparticles and soluble P-selectin were significantly higher in group 1 compared to group 2 (45.70±10.30 vs 10.60±0.96, and 51.46±9.30 vs 9.16±1.04, respectively) (p<0.001). There was no significant difference in levels of platelet-derived microparticles and soluble P-selectin in three intervals after acute myocardial infarction (p>0.05). Although levels of platelet-derived microparticles and soluble P-selectin did not correlate to creatinekinase-myocardial band levels (p>0.05), but there was a trend of significant correlation with cardiac troponin T (p<0.05). CONCLUSIONS: Levels of platelet-derived microparticles and soluble P-selectin can be used as novel early diagnostic marker of acute myocardial infarction.

IFN-α, IFN-ß, and IFN-γ Have Different Effect on the Production of Proinflammatory Factors Deposited in Weibel-Palade Bodies of Endothelial Cells Infected with Herpes Simplex Virus Type 1.

We demonstrated similarities and differences in the effects of IFN-α and IFN-ß compared to IFN-γ on the production of factors deposited in the Weibel-Palade bodies in cultures of endothelial cells (intact and infected with herpes simplex virus 1). IFN-α and IFN-ß reduced the content of von Willebrand factor, endothelin-1, and soluble P-selectin and increased IL-8 concentration in the culture medium of human umbilical vein endothelial cells. IFN-γ reduced the content of all studied factors in the endothelial cell culture medium. Possible mechanisms of these effects are discussed.

Association between endothelial and platelet function markers and adiponectin in renal transplanted recipients on cyclosporine and tacrolimus immunosuppression based therapy.

AIM: Coagulation abnormalities, endothelial dysfunction and arteriosclerosis play a key role in cardiovascular disease state observed in transplanted patients. Plasma adiponectin levels are lower following kidney transplantation. However, there is still a debate about this topic in the literature. This study evaluated, adiponectin levels associated with markers of endothelial dysfunction and platelet function in renal transplant patients. METHODS: Sixty-six renal transplant patients were studied. Patients were grouped according to immunosuppression regimen. Group 1 (n = 36) were treated with cyclosporine A based regimes and group 2 (n = 30) were treated with tacrolimus based regimes. Plasma adiponectin, asymmetric dimethyl arginine (ADMA), sP-selectin levels and platelet aggregation tests were studied and were compared with those in control group (n = 15, group 3). RESULTS: Adiponectin, sP-selectin and ADMA levels were higher in group 1 and statistically significant differences were observed compared with those of group 2 and group 3, respectively (P < 0.001, P < 0.05, P < 0.05). Platelet aggregation values induced by agonists were lower in group 1 than group 2 and group 3, but the difference did not reach statistical significance (P > 0.05). CONCLUSION: Adiponectin levels are elevated in line with ADMA and sP-selectin levels. Since CsA induces higher adiponectin levels, platelet activation and endothelial dysfunction. These changes may be responsible for the increased risk of post-transplant cardiovascular events in renal transplant patients.

Association of PS gene polymorphism and soluble P-selectin levels in atrial fibrillation thromboembolism population in Xinjiang.

UNLABELLED: To investigate the association between the polymorphism of P choose element (p. selectin, PS) and soluble P-selectin levels in atrial fibrillation (AF) thromboembolism in Han and Uigur population of Xinjiang. METHOD: Using ELISA method determination of plasma level of sPs. The frequency distributions of SNP sP-selectin gene promoter (-2123C/G) and SNP in exon region (Thr715Pro) were investigated by polymerase chain reaction (PCR)-restriction fragment length polymorphism and direct DNA sequence analysis among 302 Xinjiang Uigur and 340 age- and sex-matched Han people. RESULTS: Cases sPs exist significant difference serum level and the control group. The frequencies of the -2123C/G allele among the Uigur population had no significant differences from those of the Han population. Thr715Pro did not show any polymorphism in the two populations. CONCLUSIONS: The sP-selectin gene polymorphisms are associated with serum sP-selectin levels or thromboembolic events, suggesting that the patients with nonvalvular AF and thromboembolic events may have genetic susceptibility.

The association of the Thr715Pro P-selectin genotype with levels of P-selectin in platelet concentrates.

BACKGROUND AND OBJECTIVES: P-selectin is stored in the alpha granules of platelets and in the Weibel Palade bodies of endothelial cells; upon activation, it is translocated to the cell surface and released into the plasma in soluble form. One variant of the P-selectin gene, the Thr715Pro polymorphism, is strongly associated with the plasma levels of soluble P-selectin. In platelet concentrates soluble P-selectin can be regarded mainly platelet derived. MATERIALS AND METHODS: The relation of the genotype with soluble P-selectin, platelet expressed P-selectin and the sum of all forms of P-selectin - comprising soluble P-selectin, platelet surface P-selectin and P-selectin from the alpha granules - was assessed in fresh whole blood and in apheresis platelets suspended in 35% plasma/65% SSP+ obtained from 89 platelet donors. RESULTS: Levels of total P-selectin were genotype associated (P = 0·025); likewise, in fresh whole blood there was an association of soluble P-selectin with genotype (P = 0·02). In platelets suspended in additive solution, however, levels of the storage-associated or TRAP-6 agonist induced increase of platelets' P-selectin were not associated with the genotype. A correlation between levels of soluble P-selectin and surface expression of P-selectin was observed on day 3 of storage in Thr715Thr individuals (P < 0·0001), but not in heterozygotes (Thr715Pro, P = 0·2). CONCLUSION: The donors' genotype has only little influence on levels of soluble P-selectin in apheresis platelets suspended in 35% plasma/65% SSP+.

Biomarkers of in vivo platelet activation in thoroughbreds during their first long-term training.

Physical exercise has an activating effect on platelet function that differs between trained and untrained subjects, depending on the type of exercise and training status. In humans, soluble P-selectin (sP-sel) and platelet-derived extracellular vesicles (PEVs) are considered reliable markers of in vivo platelet activation during exercise. In untrained humans, they increase after transient physical exercise, whereas long-term training induces a decrease in their resting levels due to an improved ability to adapt to hemodynamic changes. The aim of this study was to assess whether circulating levels of sP-sel and PEVs may be useful markers to explore in vivo platelet function in never-trained Thoroughbreds during their first 4 months of incremental training. A total of 29 clinically healthy, untrained Thoroughbreds (17 males and 12 females) were enrolled. All horses were trained with the same training schedule (90 days). Blood samples were collected on the day the training program began (T0), 30 days (T30), and 90 days (T90) after its incremental increase to quantify platelet count, sP-sel (horse enzyme-linked immunosorbent assay) and PEVs (flow cytometry). Statistical analysis was performed using RM one-way analysis of variance with the Geisser-Greenhouse correction. Soluble P-selectin tended to increase at T30 compared with T0, while T90 levels returned to baseline values. Significantly higher circulating levels of PEVs CD61+/AnnV+ were observed at T30 and T90 compared to baseline confirming platelet hyperactivity. The detection and quantification of sP-sel and PEVs in equine racehorses during the training period appears to be a promising tool to study exercise-induced primary hemostatic changes and may provide an important marker for exercise selection.

Systemic biomarkers of microvascular alterations in type 1 diabetes associated neuropathy and nephropathy - A prospective long-term follow-up study.

INTRODUCTION: This study aimed to investigate circulating biomarkers associated with the risk of developing diabetic peripheral neuropathy (DPN) and nephropathy in type 1 diabetes (T1D). MATERIALS AND METHODS: Patients with childhood-onset T1D (n = 49, age 38.3 ± 3.8 yrs.) followed prospectively were evaluated after 30 years of diabetes duration. DPN was defined as an abnormality in nerve conduction tests. Matrix metalloproteinase-9 (MMP-9) and its tissue inhibitor TIMP-1, neutrophil gelatinase-associated lipocalin-2 (NGAL), soluble P-selectin (sP-selectin), estimated GFR (eGFR), micro/macroalbuminuria and routine biochemistry were assessed. For comparison, control subjects were included (n = 30, age 37.9 ± 5.5 yrs.). RESULTS: In all, twenty-five patients (51 %) were diagnosed with DPN, and nine patients (18 %) had nephropathy (five microalbuminuria and four macroalbuminuria). Patients with DPN had higher levels of TIMP-1 (p = 0.036) and sP-selectin (p = 0.005) than controls. Patients with DPN also displayed higher levels of TIMP-1 compared to patients without DPN (p = 0.035). Patients with macroalbuminuria had kidney disease stage 3 with lower eGFR, higher levels of TIMP-1 (p = 0.038), and NGAL (p = 0.002). In all patients, we found only weak negative correlations between eGFR and TIMP-1 (rho = -0.304, p = 0.040) and NGAL (rho = -0.277, p = 0.062, ns), respectively. MMP-9 was higher in patients with microalbuminuria (p = 0.021) compared with normoalbuminuric patients. CONCLUSIONS: Our findings indicate that TIMP-1 and MMP-9, as well as sP-selectin and NGAL, are involved in microvascular complications in T1D. Monitoring and targeting these biomarkers may be a potential strategy for treating diabetic nephropathy and neuropathy.

Platelet-derived circulating soluble P-selectin is sufficient to induce hematopoietic stem cell mobilization.

BACKGROUND: Granulocyte colony-stimulating factor (G-CSF)-mediated mobilization of hematopoietic stem cells (HSCs) is a well-established method to prepare HSCs for transplantation nowadays. A sufficient number of HSCs is critical for successful HSC transplantation. However, approximately 2-6% of healthy stem cell donors are G-CSF-poor mobilizers for unknown reasons; thus increasing the uncertainties of HSC transplantation. The mechanism underlining G-CSF-mediated HSC mobilization remains elusive, so detailed mechanisms and an enhanced HSC mobilization strategy are urgently needed. Evidence suggests that P-selectin and P-selectin glycoprotein ligand-1 (PSGL-1) are one of the cell-cell adhesion ligand-receptor pairs for HSCs to keep contacting bone marrow (BM) stromal cells before being mobilized into circulation. This study hypothesized that blockage of PSGL-1 and P-selectin may disrupt HSC-stromal cell interaction and facilitate HSC mobilization. METHODS: The plasma levels of soluble P-selectin (sP-sel) before and after G-CSF administration in humans and male C57BL/6J mice were analyzed using enzyme-linked immunosorbent assay. Male mice with P-selectin deficiency (Selp-/-) were further employed to investigate whether P-selectin is essential for G-CSF-induced HSC mobilization and determine which cell lineage is sP-sel derived from. Finally, wild-type mice were injected with either G-CSF or recombinant sP-sel to investigate whether sP-sel alone is sufficient for inducing HSC mobilization and whether it accomplishes this by binding to HSCs and disrupting their interaction with stromal cells in the BM. RESULTS: A significant increase in plasma sP-sel levels was observed in humans and mice following G-CSF administration. Treatments of G-CSF induced a decrease in the level of HSC mobilization in Selp-/- mice compared with the wild-type (Selp+/+) controls. Additionally, the transfer of platelets derived from wild-type mice can ameliorate the defected HSC mobilization in the Selp-/- recipients. G-CSF induces the release of sP-sel from platelets, which is sufficient to mobilize BM HSCs into the circulation of mice by disrupting the PSGL-1 and P-selectin interaction between HSCs and stromal cells. These results collectively suggested that P-selectin is a critical factor for G-CSF-induced HSC mobilization. CONCLUSIONS: sP-sel was identified as a novel endogenous HSC-mobilizing agent. sP-sel injections achieved a relatively faster and more convenient regimen to mobilize HSCs in mice than G-CSF. These findings may serve as a reference for developing and optimizing human HSC mobilization in the future.

Platelet function and soluble P-selectin in patients with primary immune thrombocytopenia.

BACKGROUND: The bleeding phenotype in immune thrombocytopenia (ITP) is heterogeneous, but usually mild and only partly dependent on the severity of thrombocytopenia. Platelet reactivity has previously been suggested to underly the mild phenotype. METHODS: Platelet function was assessed as basal and agonist-induced surface expression of P-selectin and activation of GPIIb/IIIa via flow cytometry, and soluble (s)P-selectin levels were assessed in plasma of 77 patients with primary ITP, 19 hemato-oncologic thrombocytopenic controls (TC) and 20 healthy controls (HC). The association of platelet function with laboratory and clinical parameters such as bleeding manifestations at inclusion and previous thrombosis was analyzed. RESULTS: ITP patients showed tendency towards increased surface P-selectin and elevated levels of activated GPIIb/IIIa. Platelet activation after stimulation with all agonists including TRAP-6, ADP, arachidonic acid and CRP was decreased compared to HC. Compared to TC, only GPIIb/IIIa activation but not surface P-selectin was higher in ITP. Levels of soluble (s)P-selectin were significantly higher in ITP patients compared to TC, but similar to HC. Higher sP-selectin levels were associated with blood group O and current therapy, with highest levels in TPO-RA treated patients. Platelet reactivity was not associated with platelet count or size, platelet antibodies, treatment regime, or blood group. No correlation between platelet activation with the bleeding phenotype or previous thrombotic events could be observed. CONCLUSION: ITP patients did not have hyper-reactive platelets compared to HC, but partly higher reactivity compared to TC. Further studies are needed to understand the underlying mechanism behind the bleeding and pro-thrombotic phenotype in ITP. 250/250.

The impact of SELP gene Thr715Pro polymorphism on sP-selectin level and association with cardiovascular disease in Saudi diabetic patients: A cross-sectional case-control study.

Background: Cardiovascular diseases (CVD) are leading cause of mortality in patients with type 2 diabetes mellitus (T2DM). Increased soluble sP-selectin and 715Thr > Pro polymorphism were studied in CVD and T2DM, but association between them hasn't been explored in Saudi Arabia. We aimed to assess sP-selectin levels in T2DM and T2DM-associated CVD patients in comparison to healthy control cohort. Also, we sought to investigate relationship between Thr715Pro polymorphism and sP-selectin levels and disease state. Methods: This is a cross-sectional case-control study. sP-selectin level (measured by Enzyme-linked immunosorbent assay) and prevalence of Thr715Pro polymorphism (assessed by Sanger sequencing) were investigated in 136 Saudi participants. The study comprised 3 groups: group1 included 41 T2DM patients; group 2 (48 T2DM patients with CVD), and group 3 (47 healthy controls). Results: sP-selectin levels were significantly higher in diabetics and diabetics + CVD groups as compared to the corresponding control. In addition, results showed that the prevalence of 715Thr > Pro polymorphism is 11.75 % in the study population amongst the three study groups (9.55 % Thr/Pro, and 2.2 % Pro/Pro). No statistical difference was found between sP-selectin levels in subject carrying the wildtype genotype of this polymorphism and these who carry the mutant gene. There could be an association between this polymorphism and T2DM, whilst the polymorphism may protect diabetic patients from having CVD. However, odds ratio is not statistically significant in both cases. Conclusion: Our study supports the previous researches' results that Thr715Pro is neither influencing the sP-selectin level nor the risk of CVD in T2DM patients.

Increased plasma level of soluble P-selectin in non-hospitalized COVID-19 convalescent donors.

BACKGROUND: The coronavirus disease-2019 (COVID-19) is a systemic disease with severe implications on the vascular and coagulation system. A procoagulant platelet phenotype has been reported at least in the acute disease phase. Soluble P-selectin (sP-sel) in the plasma is a surrogate biomarker of platelet activation. Increased plasma levels of sP-sel have been reported in hospitalized COVID-19 patients associated with disease severity. Here, we evaluated in a longitudinal study the sP-sel plasma concentration in blood donors who previously suffered from moderate COVID-19. METHODS: 154 COVID-19 convalescent and 111 non-infected control donors were recruited for plasma donation and for participation in the CORE research trial. First donation (T1) was performed 43-378 days after COVID-19 diagnosis. From most of the donors the second (T2) plasma donation including blood sampling was obtained after a time period of 21-74 days and the third (T3) donation after additional 22-78 days. Baseline characteristics including COVID-19 symptoms of the donors were recorded based on a questionnaire. Platelet function was measured at T1 by flow cytometry and light transmission aggregometry in a representative subgroup of 25 COVID-19 convalescent and 28 control donors. The sP-sel plasma concentration was determined in a total of 704 samples by using a commercial ELISA. RESULTS: In vitro platelet function was comparable in COVID-19 convalescent and control donors at T1. Plasma samples from COVID-19 convalescent donors revealed a significantly higher sP-sel level compared to controls at T1 (1.05 ± 0.42 ng/mL vs. 0.81 ± 0.30 ng/mL; p < 0.0001) and T2 (0.96 ± 0.39 ng/mL vs. 0.83 ± 0.38 ng/mL; p = 0.0098). At T3 the sP-sel plasma level was comparable in both study groups. Most of the COVID-19 convalescent donors showed a continuous decrease of sP-sel from T1 to T3. CONCLUSION: Increased sP-sel plasma concentration as a marker for platelet or endothelial activation could be demonstrated even weeks after moderate COVID-19, whereas, in vitro platelet function was comparable with non-infected controls. We conclude that COVID-19 and additional individual factors could lead to an increase of the sP-sel plasma level.