ceroidlipofuscin

Ceroid lipofuscin is an autofluorescent lysosomal storage pigment that accumulates in aging and in various pathological conditions. It is a heterogeneous complex consisting mainly of oxidized lipids and crosslinked proteins that are resistant to complete lysosomal degradation. The material is deposited as residual bodies within lysosomes and, when present in large amounts, can form visible inclusions in various cell types.

It forms as a byproduct of lipid peroxidation and impaired autophagic/lysosomal processing of cellular components. The pigment is particularly enriched in long-lived postmitotic cells such as neurons, but can also be found in retinal pigment epithelium, cardiac muscle, and other tissues. In normal aging, ceroid lipofuscin accumulates gradually; in disease states, accumulation occurs at an accelerated rate.

Clinically, ceroid lipofuscin is a hallmark of neuronal ceroid lipofuscinoses, a group of inherited lysosomal storage disorders also known as Batten disease. These disorders are characterized by progressive neurodegeneration, seizures, vision loss and motor decline, with abundant storage material in neurons and glia. Ceroid lipofuscin is also observed in other neurodegenerative diseases and metabolic syndromes associated with lysosomal dysfunction.

Detection relies on its bright autofluorescence under ultraviolet or blue light and on histological examination revealing dense, osmiophilic, fingerprint-like lysosomal inclusions on electron microscopy. The pigment can be distinguished from age-related lipofuscin by its distribution, increased abundance in pathology, and ultrastructural features.