Professor Campbell has pioneered the use of cell culture to study interactions between the constituents of the vascular wall, important in development of atheroschlerosis and restenosis after angioplasty. Her seminal discovery is that in most cases before mature smooth muscle cells (SMC) of the artery wall can divide, they must undergo a reversible change in phenotype. She subsequently described phenotype-dependent changes in matrix synthesis, lipoprotein metabolism, cell surface receptor expression and the expression of various genes. Her work has profoundly influenced concepts on formation and atherosclerotic plaques, and stimulated ideas on SMC diversity.