Orsolya Tóth

Multiple electrode aggregometry: A new device to measure platelet aggregation in whole blood

Several methods are used to analyse platelet function in whole blood. A new device to measure whole blood platelet aggregation has been developed, called multiple electrode platelet aggregometry (MEA). Our aim was to evaluate MEA in comparison with the single platelet counting (SPC) method for the measurement of platelet aggregation and platelet inhibition by aspirin or apyrase in diluted whole blood. Platelet aggregation induced by different concentrations of ADP, collagen and TRAP-6 and platelet inhibition by apyrase or aspirin were determined in citrateor hirudin-anticoagulated blood by MEA and SPC. MEA indicated that spontaneous platelet aggregation was lower, and stimulated platelet aggregation was higher in hirudin- than citrate-anticoagulated blood. In hirudin-anticoagulated, but not citrate-anticoagulated blood, spontaneous platelet aggregation measured by MEA was inhibited by apyrase. For MEA compared with SPC the dose response-curves of agonist-induced platelet aggregation in citrate- and hirudin-blood showed similar EC50 values for TRAP, and higher EC50 values for ADP (non-significant) and collagen (p < 0.05). MEA and the SPC method gave similar results concerning platelet-inhibition by apyrase and aspirin. MEA was more sensitive than SPC to the inhibitory effect of aspirin in collagen-induced aggregation. In conclusion, MEA is an easy, reproducible and sensitive method for measuring spontaneous and stimulated platelet aggregation, and evaluating antiplatelet drugs in diluted whole blood. The use of hirudin as an anticoagulant is preferable to the use of citrate. MEA is a promising technique for experimental and clinical applications.

Glycoprotein Ibα inhibition and ADP receptor antagonists, but not aspirin, reduce platelet thrombus formation in flowing blood exposed to atherosclerotic plaques

Anti-platelet drugs are used to prevent intra-arterial thrombus formation after rupture of atherosclerotic plaques. Until now, the inhibitory effect of present and future anti-platelet drugs such as aspirin, ADP receptor P2Y(1)/P2Y(12) antagonists and glycoprotein (GP) Ibalpha inhibitors on the interaction of platelets with human plaques is not known. To study those effects we obtained human atherosclerotic plaques by surgical endarterectomy. Plaques induced maximal platelet aggregation in hirudinized platelet-rich plasma (PRP) and blood that was effectively inhibited by aspirin, the P2Y(1) antagonist MRS2179 and the P2Y(12) antagonist AR-C69931MX, but not by GPIbalpha blockade with the mAB 6B4. Inhibition of platelet aggregation by MRS2179 was 74 +/- 37% and 68 +/- 20%, by AR-C69931MX 94 +/- 7% and 80 +/- 6%, and by aspirin 88 +/- 19% and 64 +/- 28%, in PRP and blood, respectively (mean +/- SD; n = 6-12 with plaques from 6 patients). The combination of both ADP receptor antagonists completely inhibited plaque-induced platelet aggregation in hirudinized PRP and blood. Under arterial flow conditions (1,500s(-1)), blockade of platelet GPIbalpha resulted in a strong decrease of plaque-stimulated platelet adhesion/aggregate formation of 77 +/- 5% (mean +/- SD; n = 4). Furthermore, MRS2179, AR-C69931MX and their combination reduced plaque-dependent platelet aggregate formation by 35 +/- 14%, 32 +/- 13% and 58 +/- 12% (mean +/- SD; n = 5), respectively. Aspirin was without significant effect. In conclusion, a GPIbalpha-blocking antibody, as well as P2Y(1) and P2Y(12) receptor antagonists, alone or in combination, reduce in contrast to aspirin human plaque-induced platelet thrombus formation under arterial flow. Although these new anti-platelet agents inhibit platelet thrombus formation after plaque rupture, more efficient platelet blockers are required.

Challenges in the evaluation of D-dimer and fibrinogen levels in pregnant women

INTRODUCTION Normal pregnancy is associated with hypercoagulable state. Elevated markers of coagulation and fibrinolytic system activation indicate increased thrombin activity and increased fibrinolysis following fibrin formation throughout pregnancy. These changes exceed the biological variability in most cases. Haemostatic reference intervals are generally based on samples from non-pregnant women. Thus, they may not be relevant to pregnant women, a problem that may hinder accurate diagnosis and treatment of haemostatic disorders during pregnancy. The aim of the study was to follow the changes of haemostatic parameters and to establish gestational age-specific reference intervals during normal pregnancy. MATERIALS AND METHODS Blood samples of 83 pregnant women were collected at gestational weeks 16, 26 and 36. Fibrinogen, D-dimer, and C-Reactive Protein (CRP) were examined. Reference intervals were calculated for fibrinogen, D-dimer tests with two different methods (mean±2 SD or median and 2.5th and 97.5th percentiles with 90% confidence intervals). RESULTS fibrinogen and D-dimer increased progressively throughout pregnancy. Mean fibrinogen levels were higher than the maximum of the conventional reference interval, already in the 16th week of pregnancy. D-dimer levels were at or above the conventional cutoff point (250ng/mL) throughout the pregnancy in 42% of pregnant women, while in the 36th week 98% of them displayed elevated D-dimer levels. CRP did not increase in normal pregnancy. CONCLUSIONS There seems to be an emerging need to reconsider fibrinogen and D-dimer values from a different aspect in pregnancy compared to non-pregnant reference intervals. New reference ranges are suggested to be established in pregnancy.

Different Effect of IgA Nephropathy and Polycystic Kidney Disease on Arterial Stiffness

Background: Renal function is a major predictor of vascular function and cardiovascular diseases. Little information exists about the effect of specific renal diseases on vascular function in chronic kidney diseases (CKD). Methods: One hundred and twenty patients (60 with IgA nephropathy, IgAN, and 60 with polycystic kidney disease, PKD) with CKD stages 1–4 were studied and compared. Pulse-wave velocity was measured by the digital volume pulse (DVP) method and stiffness index (SIDVP) was derived. Results: All CKD (IgAN and PKD) patients had increased SIDVP compared to controls (10.39 vs. 8.87 ± 1.79 m/s, p = 0.008). PKD patients had increased SIDVP compared to IgAN and controls (11.14 ± 2.19, 9.66 ± 2.02 and 8.87 ± 1.79 m/s, respectively, p < 0.001). An inverse correlation was found between SIDVP and glomerular filtration rate in all CKD (IgAN and PKD) patients (p = 0.001) and in IgAN alone (p < 0.01), but not in PKD. With multivariate regression analysis, only age and 24-hour systolic blood pressure exerted independent effects on SIDVP. Conclusions: Compared to controls, arterial stiffness was increased in CKD patients. However, arterial stiffening was more pronounced in PKD than in IgAN, suggesting that vascular function is not similarly altered in etiologically different CKD groups. The fact that blood pressure was an independent risk factor underscores a therapeutic opportunity.

Autológ haemopoeticus őssejt-transzplantáció szerepe T-sejtes lymphomában. Magyar adatok

T-cell lymphoma is a poor prognostic hematological malignancy. The generally used - not sufficiently effective - induction chemotherapy should be improved with consolidative autologous hemopoetic stem cell transplantation. The authors describe the role, place and effectiveness of transplantation in this disorder. One hundred thirty three autologous stem cell transplantations were performed in the last 22 years in Hungary. Detailed results are available from the last 6 years. In this period 43 transplantations were carried out in 4 Hungarian centers. Carmustine-etoposide-cytosine arabinoside-melphalan (BEAM) conditioning regimen was used in 95%. The transplantation was done mainly in complete remission (84%), 1 year after transplantation 65% of patients were still in complete remission. Eleven patients died, 82% of them have progressive disease. Brentuximab vedotin has already proved the effectiveness, several other chemoterapeutics, monoclonal antibodies, kinase inhibitors are under investigation. In certain cases allogeneic stem cell transplantation has real indication among therapeutic options. Orv Hetil. 2017; 158(41): 1615-1619.Absztrakt: A T-sejtes lymphoma rossz prognozisu hematologiai malignitas. Az altalanossagban alkalmazott – nem kellően hatekony – indukcios kemoterapiat javitani lehet konszolidativ autolog haemopoeticus őssejt-transzplantacioval. A szerzők ismertetik az autolog atultetes szerepet, helyet, hatasossagat ebben a betegcsoportban. Az elmult 22 ev alatt Magyarorszagon 133 autolog atultetest vegeztek T-sejtes lymphomaban. Reszletesebb adatok hat ev transzplantacios eredmenyeiről allnak rendelkezesre. Ebben a periodusban 43 atultetes tortent a negy magyar centrumban kozel azonos esetszamokkal. Kondicionalo kezeleskent 95%-ban carmustin-etoposid-cytosin arabinosid-melphalan (BEAM) semat hasznaltak. Az esetek dontő tobbsegeben komplett remisszioban tortent az atultetes (84%), a beavatkozas utan egy evvel a betegek 65%-a volt komplett remisszioban. Tizenegy beteg halt meg a vizsgalt periodusban, 82%-uk alapbetegseg progressziojaban. Az uj szerek kozul a brentuximab vedotin mar bizonyitotta hatasossagat, szamos egyeb...