CD68 and atherosclerosis: In fact, although the first stages of human atherosclerosis are characterized by disruption of the internal elastic lamina(e) and the apparent transmigration of medial smooth muscle cells21 into the intima (adaptive intimal thickening),4,12,13,31,32 intact elastic lamina(e) are observed throughout the murine atherosclerotic process, and the earliest aortic and brachiocephalic lesions in the experimental models universally characterize as a subendothelial accumulation of foam cells with minimal mesenchymal cell involvement (CD68-α SMC actin double staining) (Fig 3, G).