Circulating LIGHT/TNFSF14 levels are negatively associated with cardiovascular mortality, while intra-plaque levels are associated with symptomatic cerebrovascular disease

Abstract

Abstract Funding Acknowledgements Type of funding sources: Foundation. Main funding source(s): The Swedish Heart and Lung Foundation, Åke Wiberg's Foundation Background Plaque rupture is the underlying cause of most cardiovascular events, such as stroke and myocardial infarction. Co-stimulatory molecules, the immune checkpoints, are emerging as strong candidates to battle atherosclerosis progression. The co-stimulatory molecule LIGHT (tumour necrosis factor 14; TNFSF14) exists in foam cell-rich regions of atherosclerotic plaques, but whether it is associated with a high-risk plaque phenotype and cardiovascular events is not known. Purpose This study investigates the association between intra-plaque and circulating LIGHT levels and cardiovascular disease. Method Plaque levels of LIGHT/TNFSF14 were measured in plasma and homogenised carotid endarterectomy plaques by Proximity Extension Assay in subjects from the Carotid Plaque Imaging Cohort (CPIP; N=557 and 201, respectively). Homogenates were further examined by multi-plex cytokine analysis and ELISA, and tissue plaque sections through immunohistochemistry. Multivariate Cox proportional hazards analysis was performed on normalized (logarithmically transformed) values. Results Plaque, but not circulating, levels of LIGHT were associated with the occurrence of pre-operative cerebrovascular symptoms (p=0.00014). Furthermore, intra-plaque levels of LIGHT correlated strongly with the histological plaque vulnerability index (p=5x10-15): a ratio between the sum of destabilising versus stabilising plaque components (i.e. macrophages, intra-plaque haemorrhage and lipids versus smooth muscle cells and collagen) as well as with necrotic core size and the inflammatory cytokines interleukin(IL)-1β, IL-6, chemokine (C-C motif) ligand (CCL)-2, CCL4 and CCL5. Moreover, plaque LIGHT levels correlated with several components of the extracellular matrix turnover machinery, including cleaved collagen, fibromodulin, ADAMTS7 (a disintegrin and metalloproteinase with thrombospondin motifs-7) and matrix metalloproteinases 1, 2, 9 and 10. While plaque LIGHT levels were not predictive of cardiovascular death, circulating LIGHT levels were negatively associated with risk of cardiovascular death (after 6 ½ years) after correcting for the possible confounders age, sex, cerebrovascular symptoms, diabetes, high-sensitivity C-reactive protein, inflammatory disease, hypertension and smoking (hazard ratio=0.032, confidence interval=0.420-0.951, p=0.028). Conclusion Though intra-plaque LIGHT levels are associated with a rupture-prone plaque phenotype and pre-operative symptoms, circulating levels are associated with a lower risk of future cardiovascular mortality. This suggest that upregulation of LIGHT in atherosclerotic plaques may occur as part of a reparative rupture response and, systemically, reflect efficient wound-healing capacity.