lipofuscin

thumb |Confocal microscopy|Confocal image of a spinal [[motor neuron showing stained lipofuscin granules in blue and yellow]] thumb | Micrograph showing a cluster of lipofuscin particles (arrow) in a [[nerve cell of the brain; toluidine blue stain; scale bar = 10 microns (0.01 millimeters)]] Lipofuscin is the name given to fine yellow-brown pigment granules composed of lipid-containing residues of lysosomal digestion. It is considered to be one of the aging or "wear-and-tear" pigments, found in the liver, kidney, heart muscle, retina, adrenals, nerve cells, and ganglion cells.

==Formation and turnover== thumb|right|upright=1.4|Micrograph showing lipofuscin, in brown/yellow, in a [[liver biopsy with ground glass hepatocytes; H&E stain]] Lipofuscin appears to be the product of the oxidation of unsaturated fatty acids and may be symptomatic of membrane damage, or damage to mitochondria and lysosomes. Aside from a large lipid content, lipofuscin is known to contain sugars and metals, including mercury, aluminium, iron, copper and zinc. Lipofuscin is also accepted as consisting of oxidized proteins (30–70%) as well as lipids (20–50%). It is a type of lipochrome and is specifically arranged around the nucleus.