Elastin VII: Aging effects on vascular elastica staining by oil soluble nigrosin dyes

Neutral hydroalcoholic stains with spirit soluble nigrosin (C.I. 50415) and nigrosin base (C.I. 50415B) were applied to a series of human arteries from individuals ranging from newborn to 82 years of age for the demonstration of the selective staining by these dyes of the aging change in their elastica described by Lillie, Pizzolato and Donaldson (1974). The staining is absent in infants and children. It first appears in slight grade in some individuals at age 18. It increases in frequency and intensity with advancing age. It is often seen without obvious other histologic lesion and is regularly present when fibrous and fibroatheromatous plaques appear. In this series it was studied in the aorta of children and in grossly relatively normal areas of the superior mesenteric artery which was selected for the survey because of its usual rather slight involvement in arteriosclerosis. The intensity of the neutral nigrosin staining of the elastica of this artery appeared to be uninfluenced by the extent or severity of aortic lesions in the same individual. This nigrosinophilia appears to be an integral early phase in the development of the arteriosclerotic process and may precede appearance of fibrous or fibroatheromatous plaques by some years. The nigrosinophilia has been assigned (1974) to a lipoprotein alteration of arterial elastica. Prolonged storage in formol in plastic bags induced a strong neutral Solvent black 5 and 7 staining of aortic elastica in the normally negative 10–20 year age group. This reaction is presently considered artifactual, but is being studied further experimentally.