Randomized controlled trial of aspirin and clopidogrel versus aspirin and placebo on markers of smooth muscle proliferation before and after peripheral angioplasty

Alasdair M. Wilson*, Julie Brittenden, Paul Bachoo, Isobel Ford, Graeme F. Nixon

*Corresponding author for this work

Research output: Contribution to journalArticle

9 Citations (Scopus)

Abstract

Objective: In peripheral arterial disease (PAD) patients, a limiting factor in the success of percutaneous transluminal angioplasty (PTA) is the development of restenosis secondary to vascular smooth muscle cell (SMC) proliferation. Following endothelial damage and platelet activation, there is release of factors and adhesion molecules which affect SMC proliferation. The aim of this study was to determine the effect of combination antiplatelet therapy (clopidogrel and aspirin compared with aspirin and placebo) on the ability of plasma from PAD patients undergoing PTA to stimulate SMCs in vitro. We further aimed to investigate the effect of combination treatment on the levels of circulating adhesion molecules and factors, which are known to mediate SMC proliferation in experimental models.

Methods: Fifty patients were randomized to receive blinded clopidogrel or placebo, for thirty days, in addition to their daily 75 mg aspirin. To measure proliferative capacity, diluted plasma was incubated for 15 minutes with 24 hour-growth-arrested rat vascular smooth muscle cells, and extracellular regulated kinase (ERK)1/2 activation was analyzed by Western blotting at baseline, one hour pre-PTA, one hour, 24 hours and 30 days post-PTA. Plasma platelet-derived growth factor (PDGF), sE-selectin, intracellular adhesion molecule-1 (sICAM-1), and von Willebrand factor (vWF) were measured by ELISA, at the same five timepoints. Platelet activation was measured by flow cytometry of ADP-stimulated platelet fibrinogen binding at baseline and one hour post-PTA.

Results: ADP-stimulated platelet fibrinogen binding was significantly inhibited by clopidogrel before and after PTA. ERK 1/2 activation was significantly increased post-PTA in both the aspirin/clopidogrel and aspirin/placebo groups (P <.001). There was a statistically significant decrease in PDGF (P = .004), and increase in vWF (P = .026), following loading with clopidogrel. sICAM-1 levels significantly decreased (P = .016) in the aspirin/placebo group following PTA. There were no other significant changes and also there was no statistically significant difference between the two treatment groups for each of ERK 1/2, sICAM-1, sE-selectin, or vWF.

Conclusions: This is the first study to show in-vitro ERK 1/2 activation (a surrogate marker of SMC proliferation) increases post-PTA. Combination antiplatelet therapy had no significant effect on this, although it did reduce PDGF. Further work is required to evaluate potential therapeutic treatments, which may reduce peripheral PTA-induced smooth muscle cell activation. (J Vasc Surg 2009;50:861-9.)

Original languageEnglish
Pages (from-to)861-869
Number of pages9
JournalJournal of Vascular Surgery
Volume50
Issue number4
Early online date26 Sep 2009
DOIs
Publication statusPublished - Oct 2009

Fingerprint

clopidogrel
Angioplasty
Aspirin
Smooth Muscle
Randomized Controlled Trials
Placebos
Smooth Muscle Myocytes
Selectins
Platelet-Derived Growth Factor
von Willebrand Factor
Phosphotransferases
Cell Proliferation
Peripheral Arterial Disease
Platelet Activation
Vascular Smooth Muscle
Adenosine Diphosphate
Fibrinogen
Therapeutics
Blood Platelets

Keywords

  • balloon injury
  • predicts restenosis
  • adhesion molecules
  • transluminal angioplasty
  • E-selectin
  • lower-limb
  • coronary angioplasty
  • arterial occlusive diseases
  • plasma-levels
  • intimal hyperplasia
  • randomised control trial
  • angioplasty
  • peripheral arterial disease
  • platelets
  • aspirin
  • clopidogrel
  • antiplatelet drugs
  • smooth muscle

Cite this

@article{1aee9f80f41844aa8ac4c4ac7c1c7623,
title = "Randomized controlled trial of aspirin and clopidogrel versus aspirin and placebo on markers of smooth muscle proliferation before and after peripheral angioplasty",
abstract = "Objective: In peripheral arterial disease (PAD) patients, a limiting factor in the success of percutaneous transluminal angioplasty (PTA) is the development of restenosis secondary to vascular smooth muscle cell (SMC) proliferation. Following endothelial damage and platelet activation, there is release of factors and adhesion molecules which affect SMC proliferation. The aim of this study was to determine the effect of combination antiplatelet therapy (clopidogrel and aspirin compared with aspirin and placebo) on the ability of plasma from PAD patients undergoing PTA to stimulate SMCs in vitro. We further aimed to investigate the effect of combination treatment on the levels of circulating adhesion molecules and factors, which are known to mediate SMC proliferation in experimental models.Methods: Fifty patients were randomized to receive blinded clopidogrel or placebo, for thirty days, in addition to their daily 75 mg aspirin. To measure proliferative capacity, diluted plasma was incubated for 15 minutes with 24 hour-growth-arrested rat vascular smooth muscle cells, and extracellular regulated kinase (ERK)1/2 activation was analyzed by Western blotting at baseline, one hour pre-PTA, one hour, 24 hours and 30 days post-PTA. Plasma platelet-derived growth factor (PDGF), sE-selectin, intracellular adhesion molecule-1 (sICAM-1), and von Willebrand factor (vWF) were measured by ELISA, at the same five timepoints. Platelet activation was measured by flow cytometry of ADP-stimulated platelet fibrinogen binding at baseline and one hour post-PTA.Results: ADP-stimulated platelet fibrinogen binding was significantly inhibited by clopidogrel before and after PTA. ERK 1/2 activation was significantly increased post-PTA in both the aspirin/clopidogrel and aspirin/placebo groups (P <.001). There was a statistically significant decrease in PDGF (P = .004), and increase in vWF (P = .026), following loading with clopidogrel. sICAM-1 levels significantly decreased (P = .016) in the aspirin/placebo group following PTA. There were no other significant changes and also there was no statistically significant difference between the two treatment groups for each of ERK 1/2, sICAM-1, sE-selectin, or vWF.Conclusions: This is the first study to show in-vitro ERK 1/2 activation (a surrogate marker of SMC proliferation) increases post-PTA. Combination antiplatelet therapy had no significant effect on this, although it did reduce PDGF. Further work is required to evaluate potential therapeutic treatments, which may reduce peripheral PTA-induced smooth muscle cell activation. (J Vasc Surg 2009;50:861-9.)",
keywords = "balloon injury, predicts restenosis, adhesion molecules, transluminal angioplasty, E-selectin, lower-limb, coronary angioplasty, arterial occlusive diseases, plasma-levels, intimal hyperplasia, randomised control trial, angioplasty, peripheral arterial disease, platelets , aspirin, clopidogrel, antiplatelet drugs, smooth muscle",
author = "Wilson, {Alasdair M.} and Julie Brittenden and Paul Bachoo and Isobel Ford and Nixon, {Graeme F.}",
year = "2009",
month = "10",
doi = "10.1016/j.jvs.2009.06.017",
language = "English",
volume = "50",
pages = "861--869",
journal = "Journal of Vascular Surgery",
issn = "0741-5214",
publisher = "Mosby Inc.",
number = "4",

}

TY - JOUR

T1 - Randomized controlled trial of aspirin and clopidogrel versus aspirin and placebo on markers of smooth muscle proliferation before and after peripheral angioplasty

AU - Wilson, Alasdair M.

AU - Brittenden, Julie

AU - Bachoo, Paul

AU - Ford, Isobel

AU - Nixon, Graeme F.

PY - 2009/10

Y1 - 2009/10

N2 - Objective: In peripheral arterial disease (PAD) patients, a limiting factor in the success of percutaneous transluminal angioplasty (PTA) is the development of restenosis secondary to vascular smooth muscle cell (SMC) proliferation. Following endothelial damage and platelet activation, there is release of factors and adhesion molecules which affect SMC proliferation. The aim of this study was to determine the effect of combination antiplatelet therapy (clopidogrel and aspirin compared with aspirin and placebo) on the ability of plasma from PAD patients undergoing PTA to stimulate SMCs in vitro. We further aimed to investigate the effect of combination treatment on the levels of circulating adhesion molecules and factors, which are known to mediate SMC proliferation in experimental models.Methods: Fifty patients were randomized to receive blinded clopidogrel or placebo, for thirty days, in addition to their daily 75 mg aspirin. To measure proliferative capacity, diluted plasma was incubated for 15 minutes with 24 hour-growth-arrested rat vascular smooth muscle cells, and extracellular regulated kinase (ERK)1/2 activation was analyzed by Western blotting at baseline, one hour pre-PTA, one hour, 24 hours and 30 days post-PTA. Plasma platelet-derived growth factor (PDGF), sE-selectin, intracellular adhesion molecule-1 (sICAM-1), and von Willebrand factor (vWF) were measured by ELISA, at the same five timepoints. Platelet activation was measured by flow cytometry of ADP-stimulated platelet fibrinogen binding at baseline and one hour post-PTA.Results: ADP-stimulated platelet fibrinogen binding was significantly inhibited by clopidogrel before and after PTA. ERK 1/2 activation was significantly increased post-PTA in both the aspirin/clopidogrel and aspirin/placebo groups (P <.001). There was a statistically significant decrease in PDGF (P = .004), and increase in vWF (P = .026), following loading with clopidogrel. sICAM-1 levels significantly decreased (P = .016) in the aspirin/placebo group following PTA. There were no other significant changes and also there was no statistically significant difference between the two treatment groups for each of ERK 1/2, sICAM-1, sE-selectin, or vWF.Conclusions: This is the first study to show in-vitro ERK 1/2 activation (a surrogate marker of SMC proliferation) increases post-PTA. Combination antiplatelet therapy had no significant effect on this, although it did reduce PDGF. Further work is required to evaluate potential therapeutic treatments, which may reduce peripheral PTA-induced smooth muscle cell activation. (J Vasc Surg 2009;50:861-9.)

AB - Objective: In peripheral arterial disease (PAD) patients, a limiting factor in the success of percutaneous transluminal angioplasty (PTA) is the development of restenosis secondary to vascular smooth muscle cell (SMC) proliferation. Following endothelial damage and platelet activation, there is release of factors and adhesion molecules which affect SMC proliferation. The aim of this study was to determine the effect of combination antiplatelet therapy (clopidogrel and aspirin compared with aspirin and placebo) on the ability of plasma from PAD patients undergoing PTA to stimulate SMCs in vitro. We further aimed to investigate the effect of combination treatment on the levels of circulating adhesion molecules and factors, which are known to mediate SMC proliferation in experimental models.Methods: Fifty patients were randomized to receive blinded clopidogrel or placebo, for thirty days, in addition to their daily 75 mg aspirin. To measure proliferative capacity, diluted plasma was incubated for 15 minutes with 24 hour-growth-arrested rat vascular smooth muscle cells, and extracellular regulated kinase (ERK)1/2 activation was analyzed by Western blotting at baseline, one hour pre-PTA, one hour, 24 hours and 30 days post-PTA. Plasma platelet-derived growth factor (PDGF), sE-selectin, intracellular adhesion molecule-1 (sICAM-1), and von Willebrand factor (vWF) were measured by ELISA, at the same five timepoints. Platelet activation was measured by flow cytometry of ADP-stimulated platelet fibrinogen binding at baseline and one hour post-PTA.Results: ADP-stimulated platelet fibrinogen binding was significantly inhibited by clopidogrel before and after PTA. ERK 1/2 activation was significantly increased post-PTA in both the aspirin/clopidogrel and aspirin/placebo groups (P <.001). There was a statistically significant decrease in PDGF (P = .004), and increase in vWF (P = .026), following loading with clopidogrel. sICAM-1 levels significantly decreased (P = .016) in the aspirin/placebo group following PTA. There were no other significant changes and also there was no statistically significant difference between the two treatment groups for each of ERK 1/2, sICAM-1, sE-selectin, or vWF.Conclusions: This is the first study to show in-vitro ERK 1/2 activation (a surrogate marker of SMC proliferation) increases post-PTA. Combination antiplatelet therapy had no significant effect on this, although it did reduce PDGF. Further work is required to evaluate potential therapeutic treatments, which may reduce peripheral PTA-induced smooth muscle cell activation. (J Vasc Surg 2009;50:861-9.)

KW - balloon injury

KW - predicts restenosis

KW - adhesion molecules

KW - transluminal angioplasty

KW - E-selectin

KW - lower-limb

KW - coronary angioplasty

KW - arterial occlusive diseases

KW - plasma-levels

KW - intimal hyperplasia

KW - randomised control trial

KW - angioplasty

KW - peripheral arterial disease

KW - platelets

KW - aspirin

KW - clopidogrel

KW - antiplatelet drugs

KW - smooth muscle

U2 - 10.1016/j.jvs.2009.06.017

DO - 10.1016/j.jvs.2009.06.017

M3 - Article

VL - 50

SP - 861

EP - 869

JO - Journal of Vascular Surgery

JF - Journal of Vascular Surgery

SN - 0741-5214

IS - 4

ER -