Lipofuscin

Lipofuscin is the name given to finely granular yellow brown pigment granules composed of lipid-containing residues of lysosomal digestion. It is considered one of the aging or "wear and tear" pigments; found in the liver, kidney, heart muscle, adrenals, nerve cells, and ganglion cells.It is specifically arranged around the nucleus. It does not affect normal cellular morphology and function. "Liver spots" commonly associated with aging are superficial dermal lipofuscin deposits.

Formation and turnover
It appears to be the product of the peroxidation 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, aluminum, iron, copper and zinc.

The accumulation of lipofuscin-like material may be the result of an imbalance between formation and disposal mechanisms: accumulation can be induced in rats by administering a protease; after a period of three months, the levels of the lipofuscin-like material return to normal, indicating the action of a significant disposal mechanism. However, this result is controversial, as it is questionable if the protease-induced material is true lipofuscin. There exists evidence that "true lipofuscin" is not degradable in vitro  ; whether this holds in vivo over longer time periods is not clear.

Relation to diseases
Lipofuscin accumulation is major risk factor implicated in macular degeneration, a degenerative disease of the eye.

Abnormal accumulation of lipofuscin is associated with a group of diseases of neurodegenerative disorder type called lipofuscinoses, e.g., neuronal ceroid lipofuscinosis, also known as Batten disease, as well as some other names.

Pathological accumulation of lipofuscin is implicated in Alzheimer's disease, Parkinson's disease, certain lysosomal diseases, acromegaly, denervation atrophy, lipid myopathy, chronic obstructive pulmonary disease, centronuclear myopathy.

Possible treatments
A calorie restricted diet appears to reduce or halt the production of lipofuscin.

Vitamin E appears to reduce or halt the formation of lipofuscin. Increased glutathione production also appears to retard accumulation of lipofuscin.

The nootropic drug piracetam appears to significantly reduce accumulation of lipofuscin in the brain tissue of rats.

General reviews

 * Chris Gaugler, "Lipofuscin", Stanislaus Journal of Biochemical Reviews May 1997
 * Histology at neuro.wustl.edu
 * Histology at neuro.wustl.edu

Lipofuscine Lipofuscina Lipofuscin Ліпофусцин