Arterial calcification: A new perspective?

Arterial calcification is commonly seen in atherosclerosis, chronic kidney disease (CKD) and diabetes and has long been considered a natural progression of atherosclerosis. Yet it is a systemic condition, occurring in a wide and diverse range of disease states and no medical treatment for cardiovascular disease has yet found a way to regress it; on the contrary, lipid-lowering therapy may worsen its progression. Although numerous studies have found associations between calcification and biomarkers, none has yet found a unifying mechanism that explains the calcification found in atherosclerosis, CKD or diabetes and many of the biomarkers are equally associated with atheroma development and cardiovascular events. Furthermore, both presence and absence of coronary artery calcification appear predictive of plaque rupture and cardiovascular events, indicating that the association is not causal. This suggests that we are no further forward in understanding the true nature of arterial calcification or its pathogenesis, other than noting that it is 'multifactorial'. This is because most researchers view arterial calcification as a progressive pathological condition which must be treated. Instead, we hypothesise that calcification develops as an immune response to endothelial injury, such as shear stress or oxidative stress in diabetics, and is consequently part of the body's natural defences. This would explain why it has been found to be protective of plaque rupture and why it is unresponsive to lipid-lowering agents. We propose that instead of attempting to treat arterial calcification, we should instead be attempting to prevent or treat all causes of endothelial injury.