Human C-Reactive Protein Does Not Promote Atherosclerosis in Transgenic Rabbits

Abstract

Background Although there is a statistically significant association between modestly raised baseline plasma C-reactive protein (CRP) values and future cardiovascular events, the debate is still unsettled as to whether CRP plays a causal role in the pathogenesis of atherosclerosis. Methods and Results We generated two lines of transgenic (Tg) rabbits expressing human CRP (hCRP). The plasma levels of hCRP in hCRP-Tg-1 and hCRP-Tg-2 rabbits were 0.4 ± 0.13 (n=14) and 57.8 ± 20.6 mg/L (n=12), respectively. Also, hCRP isolated from Tg rabbit plasma exhibited the ability to activate the rabbit complement. To define the role of hCRP in atherosclerosis, we compared the susceptibility of hCRP-Tg rabbits to cholesterol-rich diet-induced aortic and coronary atherosclerosis with that of non-Tg rabbits. After being fed with a cholesterol-rich diet for 16 weeks, Tg and non-Tg rabbits developed similar hypercholesterolemia and lesion sizes in both aortic and coronary arteries. Immunohistochemical staining and Western blotting revealed that hCRP was indeed present in the lesions but did not affect macrophage accumulation and smooth muscle cell proliferation of the lesions. Conclusions Neither high nor low plasma concentrations of human CRP affected aortic or coronary atherosclerosis lesion formation in hCRP-Tg rabbits.

Assessment of coronary artery disease using coronary computed tomography angiography and biochemical markers

“…CRP was initially supposed to be a causal player for atherosclerotic plaque development and inflammation [65] . However, further basic science research has questioned a direct atherogenic mechanism [66,67] . Others and we could show that serum levels of hsCRP are only weakly correlated with plaque composition and coronary artery calcification and largely determined by the presence of risk factors [58,68,69] .…”

Pathology and Pathophysiology of Atherothrombosis: Virchow's Triad Revisited

“…TF expression and its acivity in the plaques were significantly increased in CRP-transgenic rabbits. The degree of CRP deposition correlated with TF expression in plaques and thrombus size on injured plaques (Matsuda et al, 2011 Non-transgenic Rb CRP-transgenic Rb other hand, the CRP overexpression did not enhance atherosclerosis induced by hyperchoresterol diets (Koike et al, 2009). CRP localized in atherosclerotic plaques might enhance vascular wall thrombogenicity and thrombus formation after plaque disruption rather than atherogenesis.…”

“…The findings imply that CRP is implicated in atherothrombogenesis. To address this issue, CRP-transgenic rabbits were generated, because as human CRP, CRP in rabbits but not in mice works as an acute-phase reactant during inflammation (Koike et al, 2009). In the rabbits, CRP was overexpressed in livers and circulated in blood and deposited in the both SMC-rich and macrophage-rich atherosclerotic lesions.…”

Regulated conformation changes in C-reactive protein orchestrate its role in atherogenesis

“…Moreover, transgenic expression of human CRP or knock-out of endogenous CRP in atherosclerosisprone mice has been reported to accelerate [31], show no effect [32] or even protect against the development of atherosclerosis [33,34]. Knock-in of human CRP in rabbits, on the other hand, appeared to reduce the lesion formation, albeit with no statistical significance [35]. Even worse is that in vitro studies frequently generate conflicting results [36][37][38][39][40][41][42][43][44][45] and some of the reported activities of CRP have been ascribed to impurities such as azide or endotoxin [39,46,47].…”

“…Moreover, disruption of lipid rafts by MβCD or nystatin eliminated the stimulation effects of Cysmutated mCRP on EC and in rabbit vessels. Accordingly, we identified a cholesterol binding motif (CBM; a.a. [35][36][37][38][39][40][41][42][43][44][45][46][47] containing Cys36 in the sequence of human CRP which has been conserved throughout evolution. Indeed, reduction or mutating cysteines promoted the interactions of Cysmutated or reduced mCRP with both model and cell membranes.…”