Inhibition of platelet aggregation by carbon monoxide-releasing molecules (CO-RMs): comparison with NO donors

Stefan Chlopicki,Włodzimierz Buczko,Elżbieta Grochal,Roberto Motterlini,Magdalena Lomnicka,Andrzej Fedorowicz,Andrzej Mogielnicki,Karol Kramkowski

doi:10.1007/s00210-012-0732-4

Abstract

Carbon monoxide (CO) and CO-releasing molecules (CO-RMs) inhibit platelet aggregation in vitro. Herein, we compare the anti-platelet action of CORM-3, which releases CO rapidly (t ½ 1 min), and CORM-A1, which slowly releases CO (t½ = 21 min). The anti-platelet effects of NO donors with various kinetics of NO release were studied for comparison. The effects of CO-RMs and NO donors were analyzed in washed human platelets (WP), platelets rich plasma (PRP), or whole blood (WB) using aggregometry technique. CORM-3 and CORM-A1 inhibited platelet aggregation in human PRP, WP, or WB, in a concentration-dependent manner. In all three preparations, CORM-A1 was more potent than CORM-3. Inhibition of platelets aggregation by CORM-A1 was not significantly affected by a guanylate cyclase inhibitor (ODQ) and a phosphodiesterase-5 inhibitor, sildenafil. In contrast, inhibition of platelet aggregation by NO donors was more potent with a fast NO releaser (DEA-NO, t ½ = 2 min) than slow NO releasers such as PAPA-NO (t ½ = 15 min) or other slow NO donors. Predictably, the anti-platelet effect of DEA-NO and other NO donors was reversed by ODQ while potentiated by sildenafil. In contrast to NO donors which inhibit platelets proportionally to the kinetics of NO released via activation of soluble guanylate cyclase (sGC), the slow CO-releaser CORM-A1 is a superior anti-platelet agent as compared to CORM-3 which releases CO instantly. The anti-platelet action of CO-RMs does not involve sGC activation. Importantly, CORM-A1 or its derivatives representing the class of slow CO releasers display promising pharmacological profile as anti-platelet agents.

Highlights

Endogenous carbon monoxide (CO) formation in mammals is catalyzed by a family of heme oxygenase enzymes (HO), an inducible isoform (HO-1) and a constitutive protein (HO-2), that decompose heme into CO, ferrous iron, and biliverdin, the latter being converted to bilirubin by biliverdin reductase (Maines and Kappas 1977; Tenhunen et al 1969)
The CO electrode detected the release of CO from CORM-A1 in platelets rich plasma (PRP), which occurred in a slow fashion as previously described in buffer, this device was not sensitive enough to detect measurable amounts of CO from CORM-3 (Fig. 1b)
When Carbon monoxide-releasing molecules (CO-RMs) were incubated in the whole blood for few minutes, we found that carbonmonoxy hemoglobin (COHb) increased from

Summary

Introduction

Endogenous carbon monoxide (CO) formation in mammals is catalyzed by a family of heme oxygenase enzymes (HO), an inducible isoform (HO-1) and a constitutive protein (HO-2), that decompose heme into CO, ferrous iron, and biliverdin, the latter being converted to bilirubin by biliverdin reductase (Maines and Kappas 1977; Tenhunen et al 1969). Carbon monoxide-releasing molecules (CO-RMs), of which the chemical and biochemical features have been thoroughly characterized by Motterlini and co-workers (Johnson et al 2003; Motterlini 2007; Motterlini et al 2003), liberate CO in biological systems providing a useful research tool for exploring the mechanism by which CO exerts its pharmacological activities (Motterlini et al 2002) Two of these compounds, tricarbonylchloro(glycinato)ruthenium(II) (CORM-3) and sodium boranocarbonate (CORM-A1), have unique features as they are fully water-soluble and have been shown to simulate the bioactivities of gaseous CO including vessel relaxation (Clark et al 2003; Foresti et al 2003), protection against organ ischemia-reperfusion injury (Clark et al 2003; Foresti et al 2004; Guo et al 2004), prevention of organ rejection following transplantation (Clark et al 2003), and inhibition of the inflammatory response (Sawle et al 2005). The aim of the present study was to use the two mostly characterized water-soluble CO-RMs to evaluate how the different rates of CO release affect platelet aggregation in vitro and compare their anti-platelet profile with the one exerted by NO donors possessing various kinetics of NO release

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Conclusion