Immunocytochemical demonstration of lysosomal matrix vesicles in the arterial wall of the rat.

Following necrobiosis of the smooth muscle cells (SMC) of the vessel wall, lysosomes are still able to live for a time in the extracellular space. Here they are known as lysosomal matrix vesicles (MV). Their lysosomal origin can be confirmed by the immunocytochemical demonstration of beta-N-acetylglucosaminidase (beta-NAG) in extracellular MV. A positive reaction to the enzyme-cytochemical test for acid phosphatase establishes that these lysosomal MV are enzymatically active. The role of the lysosomal MV in the pathogenesis of vascular diseases is seen in an uncontrolled, locally limited destruction and alteration of the intercellular substance.