Die antikoagulatorischen Effekte von S-NO-Human Serum Albumin

Hintergrund: Neben ihren vasodilatierenden Eigenschaften wirken NO-Donatoren auch anti-inflammatorisch und neuroprotektiv. Konventionelle NO-Donatoren beeinträchtigen jedoch die Thrombozytenfunktion, da sie NO sehr schnell freisetzen. Das kann zu Blutungen führen. Der neue NO-Donator S-NO-HSA gibt im Vergleich NO langsam und in geringerer Konzentration ab. Diese Eigenschaft könnte einen günstigen Effekt auf die Blutgerinnung haben. Zielsetzung: Es sollen die antikoagulatorischen Effekte von S-NO-HSA mit jenen des konventionellen niedermolekularen NO-Donators DEA NONOate sowohl in humanen Vollblut- als auch in Plasmaproben verglichen werden.Methoden: Die antikoagulatorischen Effekte von S-NO-HSA und DEA NONOate wurden mittels Plättchenfunktionstests und Thrombelastometrie untersucht. Die Plättchenfunktionstests wurden mittels Impedanz-Aggregometrie, PFA 200 und Impact R Cone and Plate(let) Analyzer durchgeführt und Thrombelastogramme am Chrono Log Modell 700 gemessen. Die Messung der NO2-- und NO3--Konzentrationen im Plasma erfolgte mittels HPLC unter Verwendung eines Fluoreszenz- bzw. Diodenarray-Detektors.Ergebnisse: DEA NONOate führt zu weit höheren Nitrit- und Nitratspiegeln als äquimolare Mengen S-NO-HSA. Das bestätigt, dass DEA NONOate im Gegensatz zu S-NO-HSA ein s.g. „fast releasing“ NO-Donator ist. Weiters führt DEA NONOate im Gegensatz zu äquimolaren Mengen S-NO-HSA zu einer signifikanten Inhibition der Thrombozytenaggregation im Vollblut und im PRP und der primären Hämostase (PFA 200). Außerdem müssen im Vollblut wesentlich größere Mengen beider NO-Donatoren eingesetzt werden als im PRP um hämostaseologisch zu wirken („quenching effect“ des Hämoglobins).Schlussfolgerung: S-NO-HSA wirkt genauso effizient gefäßdilatierend wie die zurzeit eingesetzten NO-Donatoren, ist aber hämostaseologisch viel weniger aktiv als diese. Daher vermuten wir, dass der Einsatz von S-NO-HSA im Vergleich zu dem konventioneller NO-Donatoren beim Patienten zu weniger Nebenwirkungen, insbesondere Blutungen, führt.Background: Beside their vasorelaxing function, NO donors have been shown to act as anti-inflammatory and neuroprotective agents. Moreover, conventional NO-donors have been found to reduce platelet activation. This can cause bleeding. We propose that the new NO donor S-NO-HSA, due to its long-lasting and slow release of NO, only slightly affects platelet activation.Objectives: The aim of this diploma thesis was to compare the anticoagulant effects of S-NO-HSA with those of the conventional low molecular weight NO donor DEA NONOate in both human whole blood and plasma samples.Methods: The anticoagulant effects of S-NO-HSA and DEA NONOate were investigated by means of platelet function tests and thrombelastometry. Platelet function tests were performed by impedance aggregometry, PFA 200 and Impact R Cone and Plate(let) Analyzer and thrombelastograms were measured on the Chrono Log Model 700. Plasma NO2- and NO3- concentrations were measured by HPLC using a fluorescence- or a diode array detector.Results: DEA NONOate leads to much higher nitrite and nitrate levels than equimolar amounts of S-NO-HSA. This confirms that DEA NONOate, unlike S-NO-HSA, is a "fast releasing" NO donor. Furthermore, DEA NONOate significantly inhibited platelet aggregation in whole blood as well as in platelet rich plasma samples and primary hemostasis (PFA 200), whereas S-NO-HSA showed no effect at 200 mol/L in whole blood. Interestingly, significantly higher levels (10 times) of NO donors were required to affect haemostasis in WB compared with PRP samples.Conclusion: Administration of S-NO-HSA, due to its long-lasting release of limited amounts of NO, might be associated with less bleeding side effects in the clinical situation compared to the fast-releasing NO donors.Arbeit an der Bibliothek noch nicht eingelangt - Daten nicht geprüftAbweichender Titel laut Übersetzung des Verfassers/der VerfasserinKarl-Franzens-Universität Graz, Diplomarbeit, 2019(VLID)455221

The Antiplatelet Action of S-Nitroso Human Serum Albumin in Whole Blood

Nitric oxide donors (NO-donors) have been shown to have therapeutic potential (e.g., ischemia/reperfusion injury). However, due to their release rate/antiplatelet properties, they may cause bleeding in patients. We therefore studied the antiplatelet effects of the two different NO-donors, i.e., S-NO-Human Serum Albumin (S-NO-HSA) and Diethylammonium (Z)-1-(N,N-diethylamino)diazen-1-ium-1,2-diolate (DEA-NONOate) in whole blood (WB) samples. WB samples were spiked with S-NO-HSA or DEA-NONOate (100 µmol/L or 200 µmol/L), and the NO release rate (nitrite/nitrate levels via HPLC) and antiplatelet efficacy (impedance aggregometry, platelet function analyzer, Cone-and-platelet analyzer, thrombelastometry) were assessed. S-NO-HSA had a significantly lower NO release compared to equimolar concentrations of DEA-NONOate. Virtually no antiplatelet action of S-NO-HSA was observed in WB samples, whereas DEA-NONOate significantly attenuated platelet function in WB. Impedance aggregometry measurements revealed that Amplitudes (slope: −0.04022 ± 0.01045 ohm/µmol/L, p = 0.008) and Lag times (slope: 0.6389 ± 0.2075 s/µmol/L, p = 0.0051) were dose-dependently decreased and prolonged by DEA-NONOate. Closure times (Cone-and-platelet analyzer) were dose-dependently prolonged (slope: 0.3738 ± 0.1403 s/µmol/L, p = 0.0174 with collagen/ADP coating; slope: −0.5340 ± 0.1473 s/µmol/L, p = 0.0019 with collagen/epinephrine coating) by DEA-NONOate. These results in WB further support the pharmacological potential of S-NO-HSA as an NO-donor due to its ability to presumably prevent bleeding events even at high concentrations up to 200 µmol/L