DKK1 and osteoarthritis: Weng et al. discovered that DKK1 expression is closely correlated with the expression of pro-apoptotic factors (e.g., Bad and caspase-3) in osteoarthritis and inhibition of DKK1 expression reduced caspase-3 cleavage and alleviated chondrocyte apoptosis by reducing Bax expression and increasing Bcl-2 expression.40, 45 Cellular apoptosis is ubiquitous in vulnerable plaques; as such, recent studies on vulnerable plaques have mostly focused on inflammation and cellular apoptosis.