CCL2/CCR2 inhibition in atherosclerosis: a meta-analysis of preclinical studies

Abstract Rationale The CC-chemokine ligand-2 (CCL2)/ CC-chemokine receptor-2 (CCR2) axis governs monocyte recruitment to atherosclerotic lesions. Coherent evidence from experimental studies employing genetic deletion of CCL2 or CCR2 and human epidemiological studies support a causal involvement of the CCL2/CCR2 axis in atherosclerosis. Still, preclinical studies testing pharmacological inhibition of CCL2 or CCR2 in atheroprone mice apply widely different approaches and report inconsistent results, thus halting clinical translation. Objective To systematically review and meta-analyze preclinical studies pharmacologically targeting the CCL2/CCR2 axis in atherosclerosis in an effort to inform the design of future trials. Methods and Results We identified 14 studies testing CCL2/CCR2 inhibition using 11 different pharmacological agents in mouse models of atherosclerosis. In meta-analyses, blockade of CCL2 or CCR2 attenuated atherosclerotic lesion size in the aortic root or arch ( g =-0.75 [-1.17 to -0.32], p=6×10 −4 ; N=171/171 mice in experimental/control group), the carotid ( g =-2.39 [-4.23 to -0.55], p=0.01; N=24/25) and the femoral artery ( g =-2.38 [-3.50 to -1.26], p=3×10 −5 ; N=10/10). Furthermore, CCL2/CCR2 inhibition reduced intralesional macrophage accumulation and increased smooth muscle cell content and collagen deposition, consistent with a plaque-stabilizing effect. While there was heterogeneity across studies, the effects of CCL2/CCR2 inhibition on lesion size correlated with reductions in plaque macrophage accumulation, in accord with a prominent role of CCL2/CCR2 signaling in monocyte recruitment. Subgroup analyses revealed similar efficacy of both CCL2- and CCR2-inhibiting approaches across different atherosclerosis models in reducing lesion size and intralesional macrophage accumulation, but stronger atheroprotective effects in carotid and femoral arteries, as compared to the aorta. Conclusions Pharmacological targeting of CCL2 or CCR2 lowers atherosclerotic lesion burden and confers plaque stability in mice across different vascular territories, drug candidates, and models of atherosclerosis. Our findings in conjunction with recent human data highlight the translational potential of targeting the CCL2/CCR2 axis in atherosclerosis and can inform future clinical trials. Subject codes atherosclerosis, inflammation, vascular biology, translational studies