Microdeposits of Amyloid in the Aged and their Significance

The incidence and the organ distribution of amyloid deposits in the aged human were studied. One hundred and ten autopsied cases over seventy years old without systemic amyloidosis were examined retrospectively by polarizing microscopy of Congo red stained sections. In eighty-one cases, amyloid deposits were found in at least one of the examined organs and the overall incidence was 73.6%. Although the incidence of amyloid deposits increased with age, e. g. 65. 3% in 70-74 years old, 77.1% in 75-79, 84.6% in over 80, this phenomenon was not statistically significant. The aorta showed higher incidence (56/110, 50.9%) than other organs, e. g. pancreas (41/110, 37.3%), brain (5/22, 22.7%), seminal vesicle (3/15, 20.0%), lung (5/106, 4.7%), adrenal gland (2/95, 2.1%), kidney (2/108, 1.9%) and the heart (1/106, 0.9%). These deposits were almost always minute except those of seminal vesicle. Different mechanisms of deposition and protein natures of these ”age-related” amyloid from one organ to another have been postulated. These microdeposits of amyloid are considered to be one of the morphological changes as a result of the aging process.