BJRP 011009

Switzerland-Brazil collaborative project to reduce carotid plaque formation and vulnerability: participation of inflammatory factors (angiotensins, endocannabinoids, crp and visfatin) and novel therapies



Background: Atherosclerosis disease is one of the leading causes of morbidity and mortality in developed and developing nations. Atherosclerosis remains clinically silent over time, as long as lesions remain stable. The rupture of unstable plaques can have dramatic consequences including ischemic stroke and myocardial infarction. So far, the mechanisms of plaque stabilization remain largely unknown and it is a major goal in cardiovascular medicine. Local wall shear stress, factors from the rennin-angiotensin system (RAS) and novel inflammatory soluble mediators, such as endocannabinoids, C-reactive protein (CRP) and visfatin might also modulate plaque vulnerability.

Objectives: the major aim of this project is to investigate in symptomatic and asymptomatic patients the role of systemic and intraplaque angiotensins, endocannabinoid, CRP and visfatin levels on the chemokine receptor and adhesion molecule expression on circulating inflammatory cells (neutrophils and monocytes) within upstream and downstream regions of carotid atherosclerotic plaques.
The role of these targets will be also investigated by using an innovative mice model of shear stress-induced vulnerable atherosclerotic plaque. Finally, after characterization of inflammatory candidate genes, novel therapies will be tested to check their potential effects in plaque stabilization.

Methods: We will detect leukocyte infiltration, and inflammatory molecules production in human carotid arteries from endarterectomy and blood serum samples. Ex vivo experiments will be performed, by using RT-PCR, ELISA, flow cytometry analysis. Endocannabinoid levels in plasma and carotid atherosclerotic plaques will be determined by liquid chromatography-mass spectrometric analyses, whereas the expression levels of angiotensin1-7, CRP, visfatin, and CB1/CB2 receptors in carotid atherosclerotic plaques will be determined by quantitative RT-PCR and immunohistochemistry. Most promising gene candidates found to be regulated in human carotid artery will be tested in a well-established mice model of carotid vulnerable plaque. Analysis of mice arteries will be performed in a similar way to human tissue.

Partnership aspects: the Swiss groups will focus on the vascular problem of plaque vulnerability from human samples (Prof. François Mach, Unige) to well-established animal models (Prof. Nikos Stergiopulos, EPFL). They will search for new inflammatory candidate genes/proteins that could be determinant to stabilize atherosclerotic plaque. Immunohistochemistry analysis will be performed in collaboration with the group of Prof. Jorge Kalil. The Brazilian partner, Prof. Robson dos Santos, will implement the animal model in his laboratory to investigate the participation of angiotensin system to atherosclerotic plaque formation and stability. New molecules found to be modulated in vulnerable plaque will be further targeted as potential therapy.


Prof. F. MACH

Prof. J. KALIL