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Cardiovascular Research 2003 57(3):853-860; doi:10.1016/S0008-6363(02)00779-4
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Copyright © 2003, European Society of Cardiology

A novel S-nitrosothiol causes prolonged and selective inhibition of platelet adhesion at sites of vascular injury

Mark R Millera, Inderraj S Hanspala, Patrick W.F Hadokea, David E Newbya, Adriano G Rossib, David J Webba and Ian L Megsona,*

aCentre for Cardiovascular Science, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK
bMRC Centre for Inflammation Research, University of Edinburgh, Edinburgh EH8 9AG, UK

* Corresponding author. Tel.: +44-131-651-1193; fax: +44-131-650-6527. ian.megson{at}ed.ac.uk

Received 25 September 2002; accepted 6 November 2002


   Abstract
Top
 Abstract
1. Introduction
 2. Methods
 3. Results
 4. Discussion
 References
 
Objective: Platelet adhesion to areas of endothelial denudation following angioplasty is an important factor contributing to the limitations of this technique. Lipophilic S-nitrosothiols like S-nitroso-N-valerylpenicillamine (SNVP) are novel nitric oxide (NO) donor drugs with anti-platelet and vasodilator properties that are selective for areas of endothelial denudation. Here we assess the inhibitory effect of SNVP on platelet adhesion to angioplastied rabbit carotid arteries. Methods: A rabbit model was used to measure adhesion of radiolabelled platelets to carotid arteries following balloon angioplasty. The effects of SNVP were compared to the conventional NO donor, nitroglycerin (NTG). Electron microscopy was used to visualize adhering platelets. Results: Angioplasty resulted in endothelial denudation with only a modest reduction in vessel contractility. In vivo administration of NTG and SNVP (both 200 nmol) prevented the hyper-aggregability (~20%) of circulating platelets caused by angioplasty. However, bolus NTG failed to inhibit adhesion of radiolabelled platelets 30 min after angioplasty, despite inducing a transient 30% reduction in systemic blood pressure. In contrast, equimolar SNVP had little effect on blood pressure but markedly inhibited platelet adhesion (62% compared to control; P=0.003). Platelet adhesion was confirmed with electron microscopy. Conclusion: The prolonged effects of SNVP at sites of endothelial damage suggest that novel S-nitrosothiols might offer a means of targeted delivery of an antiplatelet agent to areas of vascular injury.

KEYWORDS ACh, acetylcholine; ADP, adenosine 5'-diphosphate; Hep-Sal, heparinised saline; L-NAME, N{omega}-nitro-L-arginine methyl ester; NO, nitric oxide; NTG, nitroglycerin; PE, phenylephrine; PRP, platelet rich plasma; SNVP, S-nitroso-N-valerylpenicillamine


   1. Introduction
Top
 Abstract
 1. Introduction
2. Methods
 3. Results
 4. Discussion
 References
 
Percutaneous transluminal coronary angioplasty is a common clinical intervention used to improve blood flow through stenosed coronary arteries. Thrombosis is a feature of angioplasty that limits the success of the procedure in the short term and is believed to contribute to vascular remodelling and, ultimately, restenosis [1–5]. Current anti-thrombotic therapies offer benefits in angioplasty, however, neointimal hyperplasia remains a major problem leading to a 15–30% incidence of restenosis [6–8].

Loss of the protective effects of endothelium-derived nitric oxide (NO) is critical to increased platelet adhesion. NO has powerful anti-platelet actions and NO donors can reduce platelet activation [9] and adhesion [10,11] following angioplasty. However, existing NO donor drugs are not selective for areas of endothelial damage and dosing is limited by systemic hypotension. S-Nitrosothiols are generally recognised to be platelet-selective NO donor drugs [12] and we have recently described several novel S-nitrosothiols, including S-nitroso-N-valerylpenicillamine (SNVP), which have a prolonged vasodilator activity that is selective for blood vessels with experimentally denuded endothelium [13].

Using a rabbit model, we tested the hypothesis that platelet adhesion to the intimal surface of common carotid arteries following angioplasty is inhibited to a greater extent by SNVP than by the conventional nitrate, nitroglycerin (NTG).


   2. Methods
Top
 Abstract
 1. Introduction
 2. Methods
3. Results
 4. Discussion
 References
 
All procedures were performed in accordance with the Animals (Scientific Procedures) Act 1986 (UK Home Office). All chemicals were obtained from Sigma, unless stated otherwise. SNVP was synthesized by a published method [14].

2.1 Surgical procedure
Adult male New Zealand white rabbits (2.5–3.5 kg; n=60) were anesthetised as previously described [15]. The left femoral artery was cannulated (3F) for the measurement of systemic blood pressure and heart rate (CAPTO SP844 transducer, AD Instruments) and 5 ml of blood was withdrawn into a MonovetteTM tube containing 0.4 ml sodium citrate (3.8%). The external carotid artery was cannulated and a 2.5x20 mm angioplasty balloon (Boston Scientific SCIMED) was passed into the common carotid artery (Fig. 1). Angioplasty was performed on a 40-mm section of artery, using 2x30 s inflations (10 atm, with a 15-s interval). The balloon was withdrawn under 4 atm pressure. Sham operations involved cannulation of the common carotid artery without balloon inflation. The artery was recannulated to administer a 0.2-ml bolus of heparinised saline (Hep-Sal; 25 U/ml; Genus Express), NTG (Schwarz Pharma) or SNVP (both 200 nmol) immediately upstream of the angioplastied region (Fig. 1). Both SNVP [13] and NTG [16] release 1 molar equivalent of NO. Blood flow over the angioplastied region was restored and animals were killed 35 min after angioplasty with pentobarbitone (Genus Express). Both common carotid arteries were dissected free and placed in standard Krebs solution [13]. Arteries were then cleaned of connective tissue and divided into rings for further assessment (Fig. 1).


Figure 1
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  		Fig. 1 Schematic representation of the surgical technique and segmentation of the isolated rabbit carotid used for experimental protocols.

 
2.2 Preparation and measurement of radiolabelled platelets
Citrated blood was centrifuged with prostacyclin (300 ng/ml; Affiniti Research Products) to obtain pelleted platelets. Platelets were radiolabelled with 111InCl3 (NENTM Life Science Products) and re-suspended in prostacyclin-free solution [17]. The final suspension contained ~330x106 platelets/ml (determined with a Coulter AC.T 8 Haematology Analyser, Coulter Electronics). Approximately 1 ml platelet suspension (50–300x106 platelets; radioactivity=50–800x103 decays per minute; dpm) was re-injected into the donor rabbit via a marginal ear vein ~10 min before angioplasty. Radioactivity of blood samples (100 µl) and segments of carotid artery (~5 mm) was assessed by a Packard 1900TR liquid scintillation analyser.

2.3 Platelet aggregation
Five ml blood samples were taken from the femoral artery before angioplasty and immediately before the animal was killed. Platelet-rich plasma (PRP; 0.5 ml) was pre-warmed to 37 °C for 5 min in a two-channel platelet aggregometer (Cronolog Ca560, Labmedics) [18]. Platelet aggregation in response to adenosine 5'-diphosphate (ADP; 8 µmol/l) was measured turbidometrically for a period of 5 min following agonist addition. On account of the small volumes of PRP available, experiments were restricted to a single concentration of ADP. Previous experiments have shown that S-nitrosothiols are capable of inhibiting aggregation in vitro in response to this concentration of ADP [19].

2.4 Organ bath studies
Vessel rings (3 mm) were suspended in a 10-ml myograph (Multi Tissue Bath System 700MO, Danish Myo Technology) and bathed in oxygenated (95% O2, 5% CO2) Krebs solution at 37 °C. Tension was applied to vessels in stepwise increments to obtain a resting tension of 7 g and allowed to equilibrate for 30–40 min. Rings were contracted (x3) to obtain the maximum contraction to high K+ Krebs (NaCl: 4.7 mmol/l; KCl: 118 mmol/l). Rings were exposed to phenylephrine (PE; 0.1–10 µmol/l) to investigate the effect of in vivo NO donor administration on blood vessel contractility. Following precontraction with EC80 PE (~3 µmol/l), endothelial cell function was assessed with acetylcholine (ACh; 0.01–30 µmol/l). Vessels were precontracted with EC50 PE (~1 µmol/l) and the response to the NO scavenger oxyhemoglobin (10 µmol/l; to inhibit both endogenous and exogenous NO) and the NO synthase inhibitor N{omega}-nitro-L-arginine methyl ester (L-NAME; 200 µmol/l; to inhibit only endogenous NO) was measured.

2.5 Electron microscopy
Segments of carotid artery (3 mm) were fixed in 3% glutaraldehyde and osmium tetroxide, dehydrated in graded acetone and critical point dried with CO2. The intimal surface was examined using a Phillips 505 scanning electron microscope following gold–palladium alloy sputter coating (SC500 Sputter coater, Emscope Laboratories). Following fixation and dehydration, several samples were imbedded in araldite and 60 nm sections cut (Reichert OMU4 Ultracut microtome). Sections were stained with uranyl acetate and lead citrate (LKB Ultrostainer) and examined using a Phillips CM12 transmission electron microscope.

2.6 Data analysis
Data analysis was carried out using GraphPad Prism (Version 3.02, GraphPad Software Inc., San Diego, CA, USA). Radiolabelled-platelet adhesion was expressed as an index, standardised to vessel length (cm) and whole blood radioactivity (dpm/100 µl blood). Thus, an index of 1.0 indicates that all the radiolabelled platelets in 100 µl of blood adhered to a 1-cm segment of vessel. Values are expressed as mean±S.E.M. Statistically significance was defined as P<0.05 (ns=non significant). ANOVA, paired and unpaired Student's t-tests, were used where appropriate.


   3. Results
Top
 Abstract
 1. Introduction
 2. Methods
 3. Results
4. Discussion
 References
 
3.1 Effect of angioplasty on vessel function
Compared to contralateral control vessels, angioplastied rings showed a 29±8% decrease in vasoconstriction to high K+ Krebs (P=0.02; n=6; Fig. 2a) and decreased maximum vasoconstriction to PE (0.1–10 µmol/l; P=0.002; n=6; Fig. 2b). Responses to high K+ Krebs and PE in sham operated vessels were not different from those in contralateral vessels (P = ns; n=7).


Figure 2
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  		Fig. 2 Vasoconstrictor responses in carotid rings from sham-operated (hatched column/filled circles), angioplastied (filled column/filled triangles) and their corresponding contralateral (open columns/open symbols) vessels to (a) high K+ (118 mmol/l) Krebs and (b) phenylephrine (PE; 0.1–10 µmol/l). Mean±S.E.M. (n=6–7). * P<0.05; ** P<0.01; ns non significant. s, sham; a, angioplasty.

 
Following precontraction with PE (2.7±0.2 µmol/l; n=12), ACh (0.01–30 µmol/l) produced a similar degree of concentration-dependent vasodilatation in un-injured contralateral arteries and sham vessels, with almost complete loss of tone at 30 µmol/l ACh (Fig. 3a). There was marked attenuation of the maximum vasodilatation to ACh in angioplastied vessels, from 90±2 to 20±10% (P<0.001; n=6).


Figure 3
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  		Fig. 3 Vasodilator responses in carotid rings from sham-operated (filled circles/hatched columns), angioplastied (filled triangles/filled columns) and their corresponding contralateral (open symbols/open columns) vessels. (a) Response to acetylcholine (ACh; 0.01–30 µmol/l). Rings are preconstricted with an EC80 dose of phenylephrine (~3 µmol/l). (b) Response to oxyhemoglobin (Hb 10 µmol/l) and N{omega}-nitro-L-arginine methyl ester (L-NAME; 200 µmol/l). Rings are preconstricted with an EC50 dose of phenylephrine (~1 µmol/l). Changes in tension are expressed as % maximum response to high K+ Krebs. Mean±S.E.M. (n=6–7). * P<0.05; ** P<0.01; *** P<0.001; ns non significant.

 
In the presence of PE (1.3±0.1 µmol/l; n=11), oxyhemoglobin (10 µmol/l) increased tone from 54±3 to 92±5% (n=7) of the maximal K+ Krebs-induced contraction in the contralateral vessels (Fig. 3b). In the same preconstricted vessels, L-NAME (200 µmol/l) increased vessel tone from 59±1 to 73±2% (n=6; Fig. 3b). These responses to oxyhemoglobin and L-NAME were similar in sham-operated in comparison to contralateral vessels (P = ns; n=6–7). In angioplastied vessels, oxyhemoglobin and L-NAME had no effect on vessel tone (P = ns; n=3–5).

The removal of endothelial cells in the intima of angioplastied arteries was confirmed by immunohistochemistry (results not shown).

3.2 Effect of drug bolus on vessel function ex vivo
Bolus administration of either NO donor immediately after angioplasty in vivo had no significant effect on responses to high K+ Krebs, PE (EC50=0.6–1.5 µmol/l), ACh (EC50=47–120 nmol/l), oxyhemoglobin or L-NAME in either angioplastied or contralateral vessels (P = ns; n=5–6 for all; results not shown).

3.3 Effect of drug bolus on blood pressure
Before angioplasty, baseline systolic and diastolic blood pressure was 61±4 and 44±3 mmHg (n=21), respectively, and heart rate 220±9 bpm (n=17). Hep-Sal bolus (0.2 ml) had no effect on blood pressure or heart rate (Table 1 and Fig. 4). NTG bolus (200 nmol) caused a significant transient reduction in both systolic and diastolic blood pressure, whereas SNVP (200 nmol) had no effect (Table 1 and Fig. 4).


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  		Table 1 The % change (mean±S.E.M.) of systolic and diastolic blood pressure, heart rate and platelet aggregation after bolus delivery of saline (200 µl), nitroglycerin (NTG, 200 nmol) and S-nitroso-N-valerylpenicillamine (SNVP, 200 nmol) following angioplasty of the carotid artery

 

Figure 4
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  		Fig. 4 Representative pressure recordings of the response to saline (control), nitroglycerin (NTG) and S-nitroso-N-valerylpenicillamine (SNVP) (both 200 nmol). Vertical dotted line represents drug administration.

 
3.4 Effect of drug bolus on platelet aggregation
Following angioplasty with Hep-Sal, there was a 9.3±2.6 mV increase (~25%) in platelet aggregation to ADP (8 µmol/l) compared to before angioplasty (Table 1). In contrast, there was no increase in aggregability of platelets in PRP from rabbits that received NTG or SNVP after angioplasty (Table 1).

3.5 Radiolabelled platelet adhesion to carotid arteries
In angioplastied vessels, there was an almost 20-fold increase in platelet adhesion (index=0.25±0.04; Fig. 5) compared to contralateral vessels (index=0.013±0.01 dpm). NTG did not reduce platelet adhesion in angioplastied vessels, in comparison to Hep-Sal (P = ns; n=6 and 7, respectively), whereas SNVP reduced it by 62±7% (P=0.003; n=7; Fig. 5): and to a greater extent than NTG (P=0.01; n=6).


Figure 5
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  		Fig. 5 Platelet adhesion to angioplastied and contralateral (uninjured) carotid arteries following drug treatment (0.2 ml; 200 nmol). Radiolabelled-platelet adhesion is expressed as dpm, standardised to vessel length and whole blood radioactivity. Vessels were isolated and platelet adhesion measured 30 min after drug treatment. Mean±S.E.M. (n=4–7). * P<0.05; ** P<0.01; ns non significant.

 
3.6 Electron microscopy
Adhesion of platelets to the lumen of blood vessels was confirmed using scanning electron microscopy (Fig. 6). Following a Hep-Sal bolus, angioplastied vessels showed adhering and activated platelets covering the entire luminal surface (Fig. 6b). Transmission electron microscopy revealed platelets with pseudopodia extending over the intimal surface and with a loss of cytoplasmic granules, confirming both adhesion and activation (Fig. 6b inset). In angioplastied vessels treated with SNVP, the number of activated platelets adhering to the luminal surface was substantially reduced (Fig. 6c).


Figure 6
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  		Fig. 6 Representative electron micrographs of the luminal surface of the common carotid arteries. (a) Contralateral (uninjured) artery, (b) angioplastied artery receiving saline bolus (0.2 ml), (c) angioplastied artery receiving SNVP bolus (200 nmol). Inset; representative transmission electron micrograph of platelets adhering to an angioplastied artery (aa). An adherent platelet (ap) has few cytoplasmic granules (g) compared to an unattached platelet (up). Vessels were isolated and fixed 30 min after drug treatment. White bar represents 10 µm (scanning electron microscopy) or 1 µm (transmission electron microscopy).

 

   4. Discussion
Top
 Abstract
 1. Introduction
 2. Methods
 3. Results
 4. Discussion
References
 
We have demonstrated that a novel S-nitrosothiol, SNVP, reduces adhesion of radiolabelled platelets to rabbit carotid arteries following angioplasty in vivo, without significantly affecting systemic blood pressure. In contrast, equimolar NTG caused an undesirable decrease (30%) in systemic blood pressure, but failed to inhibit local platelet adhesion. Both NO donors prevented circulating platelet hyper-aggregability induced by angioplasty, suggesting that the added benefits of SNVP are due to a prolonged antiplatelet action selectively at sites of endothelial cell damage.

4.1 Platelet activation and angioplasty
The major limitations of angioplasty are thrombosis and restenosis of treated arteries. The technique inevitably damages the vascular endothelium, leading to platelet activation, that is a key event in the initiation of vascular remodelling [5,20]. Current anti-thrombotic therapies, including aspirin, clopidogrel and GPIIb/IIIa antagonists, have been shown to reduce platelet adhesion and intimal thickening following angioplasty [6–8]. However, maintaining sufficiently high local drug concentration over a number of hours can be problematic [2,21,22]. Recently, sirolimus (rapamycin)-eluting stents have been shown to be particularly effective at inhibiting neointimal hyperplasia [8,23], but this approach does not have anti-platelet actions and the long-term effectiveness (>1 year) has yet to be established. Despite current advances in drug delivery catheters [2] and deployment of stents [8], endothelial cell damage and platelet activation still remain a significant problem, highlighting the need for additional therapies which counteract the multiple factors involved in the response to injury.

4.2 Role of conventional NO donors
Delivery of NO is an attractive alternative to conventional anti-thrombotic agents, because NO exhibits a range of beneficial actions, including vasodilatation, regulation of inflammatory cell function, inhibition of smooth muscle cell mitogenesis and inhibition of platelet activation [24]. Indeed, NO donors inhibit platelet activation following angioplasty [9–11,25]. The most common clinically used NO donors are the organic nitrates, such as NTG, although the selectivity profile of traditional nitrates (veins>arteries>platelets) is unfavourable. Our results are in keeping with the recognised selectivity profile of NTG; it caused a profound systemic hypotension, demonstrating that vasoactive concentrations of NTG were being used that may induce unwanted complications in patients undergoing angioplasty.

NTG is a poor inhibitor of platelet aggregation in vitro [26], possibly because PRP lacks the factors necessary for the biotransformation to active NO [27]. In vivo, NTG infusion can inhibit platelet activation, presumably via vascular tissue-mediated biotransformation of NTG to NO [28]. However, NTG failed to prevent adhesion of radiolabelled platelets to the intimal surface of angioplastied carotid arteries. These results suggest that bolus NTG can influence activation of circulating platelets, but its short-term effects are not capable of preventing adhesion to the exposed subendothelial surface [11], presumably because NTG is not selectively retained in this region. Similarly, other drugs, such as aspirin, have also been shown to prevent platelet hyper-responsiveness without reducing platelet adhesion [3].

4.3 Potential of S-nitrosothiols
S-Nitrosothiols exhibit a number of properties that might prove advantageous in angioplasty. They show greater selectivity for arteries than veins [29] and, unlike organic nitrates, are also powerful inhibitors of platelet aggregation both in vitro [19] and in vivo [12]. S-Nitrosothiols can generate sufficient NO in PRP to inhibit platelet aggregation [19]. We have previously demonstrated that SNVP causes sustained NO-mediated vasodilatation selectively in blood vessels with damaged endothelium [13]. In addition, other novel lipophilic S-nitrosothiols produce sustained vasodilatation in human arteries and veins both ex vivo [30] and in vivo [31], which may potentially be of great benefit in preventing vasospasm in angioplastied arteries. This evidence strongly suggests that locally-delivered SNVP is able to specifically target areas of endothelial damage, a feature that is not shared by conventional NO donors.

Equimolar concentrations of SNVP were compared with NTG, because both compounds release 1 molar equivalent of NO [16]. In contrast to NTG, SNVP had minimal effects on systemic blood pressure, but caused a <60% reduction in platelet adhesion to angioplastied carotid arteries. Both SNVP and NTG inhibited in vitro platelet aggregation in response to ADP, however, only SNVP inhibited platelet adhesion following angioplasty. Here, SNVP was administered as a concentrated bolus immediately upstream of the angioplastied region (Fig. 1). Our previous results [13] are consistent with the hypothesis that SNVP is retained in the exposed subendothelial layers, where it decomposes slowly, generating NO in sufficiently high concentrations to inhibit platelet adhesion locally. Similar findings with radiolabelled S-nitrosoalbumin have been confirmed to be due to adhesion of this agent to the area of injury [25]. The inhibitory effect of SNVP on platelet adhesion suggests that this compound might have therapeutic potential in the prevention of acute thrombosis at the site of angioplasty, possibly from a single administration, although its impact on long-term complications of interventional procedures remains to be determined.

4.4 Study limitations
Damaged vessels lose their hyperactivity to platelets within 8 h after injury, despite incomplete endothelial regrowth [21,32]. However, presently it is unknown whether the antiplatelet effects of SNVP persist for <30 min after angioplasty. In endothelium-denuded rat femoral arteries, ~75% of the vasodilatation to novel S-nitrosothiols is still present at 4 h [33], emphasising the long-acting nature of these compounds. This complementary vasodilator effect would be beneficial in limiting vasospasm following angioplasty. However, the results of functional experiments in the current study failed to confirm a prolonged vasodilator effect in rings from angioplastied carotid arteries treated with SNVP. There was no difference in the maximum contraction to high K+ Krebs or PE between vessels that received different NO donors and no evidence from oxyhemoglobin experiments of NO-mediated, sustained vasodilatation in SNVP-treated vessels. However, these results do not preclude the possibility that sufficient S-nitrosothiol remains in the vessel to inhibit platelet adhesion, but not to cause vasodilatation. Alternatively, the setup time and processing of the isolated carotid ring experiments may reduce the concentrations of drug retained in the tissue. Further experiments are needed to investigate the mechanism and duration of action of drugs like SNVP, and will help to establish their therapeutic potential in the prevention of restenosis, either alone or as an adjunct to current therapies.

Time for primary review 23 days.


   Acknowledgements
 
We gratefully acknowledge support from the Scottish Executive Chief Scientist Office (K/MRS/50/C2687) and the Sir Stanley and Lady Davidson Fund. DJW was the recipient of a Wellcome Trust Research Leave Fellowship (WT0526330). We also thank S. Mitchell for the processing of the electron microscopy samples and M. Patrizio for his help with the immunohistochemistry. SNVP was kindly synthesized by Dr F.A. Mazzei and Dr A.R. Butler, University of St. Andrews, UK.


   References
Top
 Abstract
 1. Introduction
 2. Methods
 3. Results
 4. Discussion
 References
 

  1. Wei-Liu M., Roubin G.S., King S.B. Restenosis after coronary angioplasty: potential biologic determinants and role of intimal hyperplasia. Circulation (1989) 79:1374–1387.[Abstract/Free Full Text]
  2. Lincoff A.M., Topol E.J., Ellis S.G. Local drug delivery for the prevention of restenosis. Fact, fancy, and future. Circulation (1994) 90:2070–2084.[Free Full Text]
  3. Clowes A.W., Karnovsky M.J. Failure of certain antiplatelet drugs to affect myointimal thickening following arterial endothelial injury in the rat. Lab Invest (1977) 36:452–464.[Web of Science][Medline]
  4. Groves H.M., Kinlough-Rathbone R.L., Richardson M., Moore S., Mustard J.F. Platelet interaction with damaged rabbit aorta. Lab Invest (1979) 40:194–200.[Web of Science][Medline]
  5. Fingerle J., Johnson R., Clowes A.W., Majesky M.W., Reidy M.A. Role of platelets in smooth muscle cell proliferation and migration after vascular injury in rat carotid artery. Proc Natl Acad Sci USA (1989) 86:8412–8416.[Abstract/Free Full Text]
  6. Topol E.J., Serruys P.W. Frontiers in interventional cardiology. Circulation (1998) 98:1802–1820.[Free Full Text]
  7. Bult H. Restenosis: A challenge for pharmacology. Trends Pharmacol Sci (2000) 21:274–279.[CrossRef][Medline]
  8. Swanson N., Stephens-Lloyd A., Gershlick A. Drug-eluting stents: From lab bench to bedside. Cardiol News (2001) 4:12–15.
  9. Langford E.J., Brown A.S., Wainwright R.J., et al. Inhibition of platelet activity by S-nitrosoglutathione during coronary angioplasty. Lancet (1994) 344:1458–1460.[CrossRef][Web of Science][Medline]
  10. Groves P., Lewis M.J., Cheadle H.A., Penny W.J. SIN-1 reduces platelet adhesion and platelet thrombus formation in a porcine model of balloon angioplasty. Circulation (1993) 87:590–597.[Abstract/Free Full Text]
  11. Lam J.Y.T., Chesebro J.H., Fuster V. Platelets, vasoconstriction, and nitroglycerin during arterial wall injury: A new antithrombotic role for an old drug. Circulation (1988) 78:712–716.[Abstract/Free Full Text]
  12. De Belder A.J., MacAllister R., Radomski M.W., Moncada S., Vallance P.J.T. Effects of S-nitroso-glutathione in the human forearm circulation: Evidence for selective inhibition of platelet activation. Cardiovasc Res (1994) 28:691–694.[Web of Science][Medline]
  13. Megson I.L., Morton S., Greig I.R., et al. N-Substituted analogues of S-nitroso-N-acetyl-DL-penicillamine: Chemical stability and prolonged nitric oxide mediated vasodilatation in isolated rat femoral arteries. Br J Pharmacol (1999) 126:639–648.[CrossRef][Web of Science][Medline]
  14. Miller M.R., Roseberry M.J., Mazzei F.A., et al. Novel S-nitrosothiols do not engender vascular tolerance and remain effective in glyceryltrinitrate-tolerant rat femoral arteries. Eur J Pharmacol (2000) 408:335–343.[CrossRef][Web of Science][Medline]
  15. Hadoke P., Wainwright C.L., Wadsworth R.M., Butler K., Giddings M.J. Characterization of the morphological and functional alterations in rabbit subclavian artery subjected to balloon angioplasty. Coron Art Dis (1995) 6:403–415.[Web of Science][Medline]
  16. Bennett B.M., Leitman D.C., Schroder H., et al. Relationship between biotransformation of glyceryl trinitrate and cyclic GMP accumulation in various cultured cell lines. J. Pharmacol. Exp. Ther. (1989) 250:316–323.[Abstract/Free Full Text]
  17. Norman K.E., Williams T.J., Rossi A.G. Comparison of the reversed passive Arthus and local Shwartzman reactions of rabbit skin: Effects of the long-acting PAF antagonist UK-74,505. Br J Pharmacol (1997) 120:1286–1293.[CrossRef][Web of Science][Medline]
  18. Megson I.L., Sogo N., Mazzei F.A., et al. Inhibition of human platelet aggregation by a novel S-nitrosothiol is abolished by haemoglobin and red blood cells in vitro: Implications for anti-thrombotic therapy. Br J Pharmacol (2000) 131:1391–1398.[CrossRef][Web of Science][Medline]
  19. Sogo N., Magid K.S., Shaw C.A., Webb D.J., Megson I.L. Inhibition of human platelet aggregation by nitric oxide donor drugs: Relative contribution of cGMP-independent mechanisms. Biochem Biophys Res Commun (2000) 279:412–419.[CrossRef][Web of Science][Medline]
  20. Friedman R.J., Stemerman M.B., Wenz B., et al. The effect of thrombocytopenia on experimental arteriosclerotic lesion formation in rabbits. J Clin Invest (1977) 60:1191–1201.[Web of Science][Medline]
  21. Groves H.M., Kinlough-Rathbone R.L., Mustard J.F. Development of nonthrombogenicity of injured rabbit aortas despite inhibition of platelet adherence. Arteriosclerosis (1986) 6:189–195.[Abstract/Free Full Text]
  22. Wolinsky H. Local delivery: Let's keep our eyes on the wall. J Am Coll Cardiol (1994) 24:825–827.[Web of Science][Medline]
  23. Sousa J.E., Costa M.A., Abizaid A.C., et al. Sustained suppression of neointimal proliferation by sirolimus-eluting stents: One-year angiographic and intravascular ultrasound follow-up. Circulation (2001) 104:2007–2011.[Abstract/Free Full Text]
  24. Megson I.L. Nitric oxide donor drugs. Drugs Future (2000) 25:701–715.[CrossRef][Web of Science]
  25. Marks D.S., Vita J.A., Folts J.D., et al. Inhibition of neointimal proliferation in rabbits after vascular injury by a single treatment with a protein adduct of nitric oxide. J Clin Invest (1995) 96:2630–2638.[Web of Science][Medline]
  26. Megson I.L., Webb D.J. Nitrate resistance in platelets from patients with stable angina pectoris. Circulation (2000) 102:E87.[Medline]
  27. Weber A.-A., Neuhaus T., Seul C., et al. Biotransformation of glyceryl trinitrate by blood platelets as compared to vascular smooth muscle cells. Eur. J. Pharmacol. (1996) 309:209–213.[CrossRef][Web of Science][Medline]
  28. Folts J.D., Stamler J., Loscalzo J. Intravenous nitroglycerin infusion inhibits cyclic blood flow responses caused by periodic platelet thrombus formation in stenosed canine coronary arteries. Circulation (1991) 83:2122–2127.[Abstract/Free Full Text]
  29. MacAllister R.J., Calver A.L., Riezebos J., Collier J., Vallance P. Relative potency of nitrovasodilators on human blood vessels: An insight into the targeting of nitric oxide delivery. J Pharmacol Exp Ther (1995) 273:1529–1537.[Abstract/Free Full Text]
  30. Sogo N., Campanella C., Webb D.J., Megson I.L. S-Nitrosothiols cause prolonged, nitric oxide-mediated relaxation in human saphenous vein and internal mammary artery: therapeutic potential in bypass surgery. Br J Pharmacol (2000) 131:1236–1244.[CrossRef][Web of Science][Medline]
  31. Sogo N., Wilkinson I.B., MacCallum H., et al. A novel S-nitrosothiol (RIG200) causes prolonged relaxation in dorsal hand veins with damaged endothelium. Clin Pharmacol Ther (2000) 68:75–81.[CrossRef][Web of Science][Medline]
  32. Dewanjee M.K., Tago M., Josa M., Fuster V., Kaye M.P. Quantification of platelet retention in aortocoronary femoral vein bypass graft in dogs treated with dipyridamole and aspirin. Circulation (1984) 69:350–356.[Abstract/Free Full Text]
  33. Megson I.L., Greig I.R., Gray G.A., Webb D.J., Butler A.R. Prolonged effect of a novel S-nitrosated glyco-amino acid in endothelium-denuded rat femoral arteries: Potential as a slow release nitric oxide donor drug. Br J Pharmacol (1997) 122:1617–1624.[CrossRef][Web of Science][Medline]

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S. Marcondes, M. H. M. Cardoso, R. P. Morganti, S. M. Thomazzi, S. Lilla, F. Murad, G. De Nucci, and E. Antunes
Cyclic GMP-independent mechanisms contribute to the inhibition of platelet adhesion by nitric oxide donor: A role for {alpha}-actinin nitration
PNAS, February 28, 2006; 103(9): 3434 - 3439.
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