Coronary heart disease: the significance of coronary pathology in infancy and the role of mitogens such as vitamin D.

Intimal hyperplasia, damage to the internal elastic lamina, and proliferation of medial smooth muscle cells characterise the early response of an artery to damage. These changes are seen in the coronary arteries of the transplanted human heart, and are commonly seen in "normal" infants. Lipid incursion occurs only later, and the end-result is atheroma. These lesions of infancy are probably pathologic rather than physiologic, and are the precursors of later coronary heart disease. The early intimal and medial changes may be immune-engendered, encouraged by mitogens such as Vitamin D, and evolve in infancy as an aberration of the normal mechanisms controlling cellular proliferation.