Genetic and atherosclerotic plaque immunohistochemical analyses do not associate reduced sclerostin expression with cardiovascular events

The sclerostin antibody romosozumab increases bone formation and decreases bone resorption, leading to increased bone mass, bone mineral density and bone strength, and reduced fracture risk. In a clinical study versus alendronate in postmenopausal women (ARCH), an imbalance in adjudicated serious cardiovascular (CV) events driven by an increase in myocardial infarction (MI) and stroke was observed.To investigate whether inhibition of sclerostin in atherosclerotic plaques may have contributed to this imbalance, sclerostin was immunostained in human plaques to determine whether it was detected in regions relevant to plaque stability. Additionally, genetic variants associated with lifelong reduced sclerostin expression were explored for associations with phenotypes including those related to bone physiology and CV risk factors/events in a population-based phenome-wide association study (PheWAS).Sclerostin expression was absent (67%) or reduced in atherosclerotic plaques and when present was in deeper regions of the plaque/wall and not in areas considered relevant to plaque stability (fibrous cap and endothelium). Natural genetic modulation of sclerostin by variants with a significant positive effect on bone physiology showed no association with lifetime risk of MI or stroke. These data do not support a causal association between sclerostin inhibition and increased risk of serious cardiovascular events.