Intimal laminated elastosis in the intrarenal arteries. An electron microscopic study

Using kidneys from diabetic patients, the morphogenesis of elastic hyperplasia ("laminated elastosis") in the intrarenal arteries was studied by electron microscopy. In the thickened intima, myointimal cells produced ground substance, collagen fibers and elastic tissue. The elastic tissue was stained black electron microscopically with orcein. Newly-formed elastic tissue in the intima was first found on either the basement membrane or basement membrane-like materials around the myointimal cells and endothelial cells. Subsequently, small areas of elastic tissue aggregated and fused to form larger areas of elastic tissue or concentric thick elastic laminae, the latter containing a large number of collagen fibrils. Upon treatment with elastase, newly-formed elastic tissue was digested, but the microfibrillar component remained unstained.