Platelet-Derived Drug Targets and Biomarkers of Ischemic Stroke-The First Dynamic Human LC-MS Proteomic Study.

(1) Objective: The aim of this dynamic LC-MS (liquid chromatography and mass spectrometry) human platelet proteomic study was to identify the potential proteins candidates for biomarkers of acute ischemic stroke (AIS), their changes during the acute phase of stroke and to define potential novel drug targets. (2) Methods: A total of 32 patients (18-80 years old) were investigated that presented symptoms of AIS lasting less than 24 h from the onset, confirmed by neurological examination and/or new cerebral ischemia visualized in the CT (computed-tomography) scans. The analysis of platelet proteome was performed using LC-MS at baseline, and then on the third and seventh day from the onset of symptoms. The control group was demographically matched without any clinical signs of acute brain injury. (3) Results: The differences between platelets, at 24 h after first symptoms of stroke subjects and the control group included: ß-amyloid A4 and amyloid-like protein 2, coactosin-like protein, thymidine phosphorylase 4 (TYMP-4), interferon regulatory factor 7 (IRF7), vitamin K-dependent protein S, histone proteins (H2A type 1 and 1-A, H2A types 2B and J, H2Av, -z, and -x), and platelet basic protein. The dynamic changes in the platelet protein concentration involved thrombospondin-1, thrombospondin-2, filamin A, B, and C. (4) Conclusions: This is the first human dynamic LC-MS proteomic study that differentiates platelet proteome in the acute phase of ischemic stroke in time series and compares the results with healthy controls. Identified proteins may be considered as future markers of ischemic stroke or therapeutic drug targets. Thymidine phosphorylase 4 (TYMP-4) holds promise as an interesting drug target in the management or prevention of ischemic stroke.

New Candidates for Biomarkers and Drug Targets of Ischemic Stroke-A First Dynamic LC-MS Human Serum Proteomic Study.

(1) Background: The aim of this dynamic-LC/MS-human-serum-proteomic-study was to identify potential proteins-candidates for biomarkers of acute ischemic stroke, their changes during acute phase of stroke and to define potential novel drug-targets. (2) Methods: A total of 32 patients (29-80 years) with acute ischemic stroke were enrolled to the study. The control group constituted 29 demographically-matched volunteers. Subjects with stroke presented clinical symptoms lasting no longer than 24 h, confirmed by neurological-examination and/or new cerebral ischemia visualized in the CT scans (computed tomography). The analysis of plasma proteome was performed using LC-MS (liquid chromatography-mass spectrometry). (3) Results: Ten proteins with significantly different serum concentrations between groups volunteers were: complement-factor-B, apolipoprotein-A-I, fibronectin, alpha-2-HS-glycoprotein, alpha-1B-glycoprotein, heat-shock-cognate-71kDa protein/heat-shock-related-70kDa-protein-2, thymidine phosphorylase-2, cytoplasmic-tryptophan-tRNA-ligase, ficolin-2, beta-Ala-His-dipeptidase. (4) Conclusions: This is the first dynamic LC-MS study performed on a clinical model which differentiates serum proteome of patients in acute phase of ischemic stroke in time series and compares to control group. Listed proteins should be considered as risk factors, markers of ischemic stroke or potential therapeutic targets. Further clinical validation might define their exact role in differential diagnostics, monitoring the course of the ischemic stroke or specifying them as novel drug targets.

Profiling the endothelial function using both peripheral artery tonometry (EndoPAT) and Laser Doppler Flowmetry (LD) - Complementary studies or waste of time?

Endothelial dysfunction (ED) plays a key role in developing of cardiovascular diseases and is an important predictor of future cardiovascular events. Nevertheless, there is no established method assessing endothelial function in general population. The most popular protocol includes the ultrasound-flow-mediated-dilation, but its repeatability is operator-dependent. We intended to compare the two other operator-independent methods assessing endothelial function - the EndoPAT and Laser Doppler flowmetry (LD), and we endeavored to place them on current individual profile of biochemical cardiovascular risk and endothelial function. A total of 61 clinically healthy subjects (aged 29 ± 1y) were investigated. The blood was collected for conventional cardiovascular risk markers, the NO-pathway metabolites (ADMA, L-arginine, SDMA), oxidative-stress-markers (MDA, thiol-index) as well as endothelial and platelet activation markers (sICAM1, sVCAM1, PAI-1, sE-selectin, sP-selectin, VEGF). Subsequently, all participants underwent examination by both EndoPAT and LD. There was a poor correlation between EndoPAT and LD results. No significant differences between participants with preserved and impaired endothelial function regarding endothelial activation nor cardiovascular risk markers were observed. Both methods assess endothelial function independently from the profile of endothelial pro/anti-inflammatory status and conventional risk factors, therefore further prospective studies are needed in order to verify their additional value in the cardiovascular risk stratification.

Endothelial Function in Children with Acute Lymphoblastic Leukemia (ALL) May Reflect the Clinical Outcome.

Endothelial dysfunction is a common feature of early complications of hemato-oncologic therapy. The aim of our study was to assess the profile of endothelial function at diagnosis time, then during initial treatment phase of acute lymphoblastic leukemia (ALL), and to verify the presence of its correlation with early clinical outcome (ECO). 28 ALL children and 18 healthy age-matched control ones were recruited. Study group was examined at baseline and at 33rd and 78th day of treatment. At each protocol step the endothelial function was assessed by measurement of sP-selectin (CD62-P), PAI-1(serpinE1), sE-selectin (CD62E), sICAM-1(sCD54), sVCAM-1(sCD106), and VEGF concentrations. Higher baseline sICAM-1 and sVCAM-1 levels and lower sP-selectin and VEGF were observed in children with ALL. sICAM-1, sVCAM-1, and sE-selectin levels were decreasing following the treatment with protocol I. Higher sE-selectin and lower baseline sICAM-1 levels were observed in children treated unsuccessfully. Lower PAI-1 levels were observed in children who survived. Higher baseline sE-selectin levels and lower sICAM-1 and VEGF were observed in children treated unsuccessfully. A decrease in sE-selectin and lower PAI-1 at the 78th day of therapy were associated with better ECO. High baseline VEGF and sE-selectin levels, significant increase in PAI-1, and low initial sICAM-1 levels are prognostics for poorer prognosis in the ALL children.

The Human Carbonic Anhydrase II in Platelets: An Underestimated Field of Its Activity.

Carbonic anhydrases constitute a group of enzymes that catalyse reversible hydration of carbon dioxide leading to the formation of bicarbonate and proton. The platelet carbonic anhydrase II (CAII) was described for the first time in the '80s of the last century. Nevertheless, its direct role in platelet physiology and pathology still remains poorly understood. The modulation of platelet CAII action as a therapeutic approach holds promise as a novel strategy to reduce the impact of cardiovascular diseases. This short review paper summarises the current knowledge regarding the role of human CAII in regulating platelet function. The potential future directions considering this enzyme as a potential drug target and important pathophysiological chain in platelet-related disorders are described.

Will the last be first and the first last? The role of classroom registers in cognitive skill acquisition.

The paper estimates the effect of students' position in the classroom register on their academic performance. We use a unique dataset from Poland which contains information on the academic outcomes of students in the humanities, science and mathematics lower secondary school exams as well as the position students occupy in their classroom register. We find that students whose names are recorded near the end of the class list have lower performance than those students whose names are recorded near the beginning of the list. The effect appears to be larger for performance in the humanities exam, and for low-achieving boys who attend large classes.

Elevated plasma ADMA contributes to development of endothelial dysfunction in children with acute lymphoblastic leukemia.

BACKGROUND: Childhood acute lymphoblastic leukemia (ALL) survivors are at higher cardiovascular risk than the general population, which may result from anthracycline-related endothelial dysfunction (ED). However, a few studies indirectly show that ED may appear in ALL children before treatment begins. Hence, in this study we intended to verify the hypothesis that ED is part of the ALL phenotype. PATIENTS/METHODS: Twenty-eight ALL children and 14 healthy age-matched control children were recruited. The study group was examined at baseline, then at the 33rd and 78th day of treatment. At each step of the protocol endothelial vasodilative function was assessed by a laser Doppler flowmeter, which was followed by blood collecting for subsequent analyses. RESULTS: Compared to controls, the study group at baseline was characterized by significantly lower endothelial vasodilative responsiveness, accompanied by elevated asymmetric dimethylarginine (ADMA) and symmetric dimethylarginine (SDMA) concentrations, which were correlated with lactate dehydrogenase (LDH) and aspartate transaminase (AST). Initial ALL treatment restored endothelial function, which followed changes in ADMA and LDH concentrations. DISCUSSION: This is the first demonstration that functionally assessed ED is present in ALL children at the diagnosis and results from elevated ADMA and parallel inflammatory ED.

Endothelial dysfunction in young healthy men is associated with aspirin resistance.

The aim of this study was to investigate the relation between endothelial dysfunction and aspirin response in a young healthy population (102 men aged 18-40). Initial concentrations of the NO pathway metabolites (ADMA, l-arginine, SDMA), cardiovascular risk markers, oxidative stress markers (MDA, thiol index), sICAM1, sVCAM1, PAI-1, sE-selectin, sP-selectin, VEGF, thromboxane B2, 6-keto-PGF1α and arachidonate-induced platelet aggregation (to separate aspirin resistant from sensitive group) were measured. Flow-mediated-vasodilation (FMD) was measured before and after intravenous infusion of 16.0 g of l-arginine. Measurements were repeated following aspirin administration (75 mg/24 h) for 4 days. Both groups were homogenous regarding demographic and biochemical characteristics reflecting cardiovascular risk. Aspirin resistant subjects were characterized by lower baseline FMD and higher FMD following aspirin and l-arginine treatment, as compared to aspirin sensitive control. MDA and nitrotyrosine were greater, whereas thiol index was lower in aspirin resistant men. The sICAM1, sVCAM1, PAI-1, sE-selectin, sP-selectin and VEGF levels were similar in the analyzed groups. Thromboxane in aspirin resistant subjects was greater both at baseline and following aspirin therapy. However, a significant decrease following aspirin treatment was present in both groups. Aspirin resistance in young men is associated with endothelial dysfunction, which could be due to oxidative stress resulting from lipid peroxidation.