Portal de Periódicos da CAPES

Lipofuscin and its Relation to Aging

1981; Elsevier BV; Linguagem: Inglês

10.1016/b978-0-12-008302-2.50011-0

0270-0794

C. L. Dolman, Patrick MacLeod,

Antioxidant Activity and Oxidative Stress

This chapter discusses lipofuscin and its relevance to the process of aging in an organism. Lipofuscin can be defined as a yellowish brown, auto fluorescent, and lipidcontaining pigment that accumulates in the cytoplasm of cells during aging. It is widely distributed in nature. In man, lipofuscin exists in nearly every part of the body, provided the body is old. The largest accumulations occur in postmitotic cells such as nerve cells and myocardium or in slowly dividing cells such as hepatocytes and adrenal cortical cells. Under the light microscope, lipofuscin consists of light yellow to brownish round or oval granules, measuring about 0.5 to 3 μm in diameter. The younger the individual, the paler, smaller, and sparser the granules tend to be. With advancing years, their numbers increase, they enlarge, and their color becomes darker and more pronounced. The light yellow is known as lipofuscin and the dark brown melanin pigments in nerve cells. Neuromelanin, found in autonomie ganglia and in the pigmented nuclei of the brain stem, consists of granules that are darker and coarser than those of lipofuscin though it behaves much more like lipofuscin than does the melanin of skin and choroid. It is believed that various degenerated cytoplasmic constituents and metabolic by-products contribute to its building blocks, that the completion of the process requires an appropriate balance of intracellular oxidants and antioxidants, and that the final storage is in lysosomes. The role of lipofuscin in the cell, once formed, is unknown, but future research in this field should shed some light on this aspect.