Lipofuscin

Source: Wikipedia, the free encyclopedia.
Confocal image of a spinal motor neuron showing stained lipofuscin granules in blue and yellow
nerve cell of the brain; toluidine blue
stain; scale bar = 10 microns (0.01 millimeters)

Lipofuscin is the name given to fine yellow-brown

adrenals, nerve cells, and ganglion cells.[3]

Formation and turnover

ground glass hepatocytes; H&E stain

Lipofuscin appears to be the product of the

lipochrome[6]
and is specifically arranged around the nucleus.

The accumulation of lipofuscin-like material may be the result of an imbalance between formation and disposal mechanisms. Such accumulation can be induced in rats by administering a protease inhibitor (leupeptin); after a period of three months, the levels of the lipofuscin-like material return to normal, indicating the action of a significant disposal mechanism.[7] However, this result is controversial, as it is questionable if the leupeptin-induced material is true lipofuscin.[8][9] There exists evidence that "true lipofuscin" is not degradable in vitro;[10][11][12] whether this holds in vivo over longer time periods is not clear.

N-retinylidene-N-retinyl-ethanolamine (A2E, a lipofuscin example)

The ABCR -/- knockout mouse has delayed dark adaptation but normal final rod threshold relative to controls.

age-related macular degeneration.[14]
From this experiment, it was concluded that ABCR has a significant role in preventing formation of A2E in extracellular photoreceptor surfaces during bleach recovery.

Relation to diseases

Micrograph of heart muscle showing lipofuscin pigment, H&E stain

Lipofuscin accumulation in the eye, is a major risk factor implicated in macular degeneration, a degenerative disease,[15] and Stargardt disease, an inherited juvenile form of macular degeneration.

In the

neurodegenerative disorders – neuronal ceroid lipofuscinoses, the most common of these is Batten disease
.

Also, pathological accumulation of lipofuscin is implicated in

lysosomal diseases, acromegaly, denervation atrophy, lipid myopathy, chronic obstructive pulmonary disease,[16] and centronuclear myopathy. Accumulation of lipofuscin in the colon is the cause of the condition melanosis coli
.

On the other hand,

myocardial lipofuscin accumulation more directly reflects chronological ageing rather than human cardiac pathology.[17]

Possible therapies

Calorie restriction,[4] vitamin E,[4] and increased glutathione
appear to reduce or halt the production of lipofuscin.

The

nootropic drug piracetam appears to significantly reduce accumulation of lipofuscin in the brain tissue of rats.[18]

Other possible treatments:

Wet

anti-aging medicine
.

Soraprazan (remofuscin) has been found to remove lipofuscin from retinal pigment epithelial cells in animals.[24] This opens up a new therapy option for the treatment of dry age-related macular degeneration and Stargardt disease, for which there is currently no treatment. The drug has now been granted orphan drug designation for the treatment of Stargardt disease by the European Medicines Agency.[25]

Other uses

Lipofuscin quantification is used for age determination in various crustaceans such as lobsters and spiny lobsters.[26][27] Since these animals lack bony parts, they cannot be aged in the same way as bony fish, in which annual increments in the ear-bones or otoliths are commonly used. Age determination of fish and shellfish is a fundamental step in generating basic biological data such as growth curves, and is needed for many stock assessment methods. Several studies have indicated that quantifying the amount of lipofuscin present in the eye-stalks of various crustaceans can give an index of their age. This method has not yet been widely applied in fisheries management mainly due to problems in relating lipofuscin levels in wild-caught animals with accumulation curves derived from aquarium-reared animals.

See also

References

  1. ^
    ISBN 978-1-4160-6257-8
    .
  2. ^ "Medical Definition of LIPOFUSCIN". www.merriam-webster.com.
  3. ^ Young B, Lowe JS, Stevens A, Heath JW. Wheater's Functional Histology: A Text and Atlas. 6th ed. Elsevier
  4. ^ a b c Chris Gaugler, "Lipofuscin Archived 2007-07-15 at the Wayback Machine", Stanislaus Journal of Biochemical Reviews May 1997
  5. S2CID 6833509
    .
  6. ^ "lipochrome", The Free Dictionary, retrieved 2021-02-18
  7. PMID 9888441
    .
  8. PMID 10476822
    .
  9. PMID 10393067
    .
  10. S2CID 34448638.{{cite journal}}: CS1 maint: multiple names: authors list (link
    )
  11. S2CID 44822239
    .
  12. PMID 7668332
    .
  13. S2CID 18605680
    .
  14. PMID 18658157
    .
  15. ^ John Lacey, "Harvard Medical signs agreement with Merck to develop potential therapy for macular degeneration", 23-May-2006
  16. S2CID 22309073
    .
  17. PMID 30824797
    .
  18. PMID 1755517
    .
  19. S2CID 29129359
    .
  20. ^ Amenta F, Ferrante F, et al., Reduced lipofuscin accumulation in senescent rat brain by long-term acetyl-L-carnitine treatment. Arch Gerontol Geriatr. 1989 Sep-Oct;9(2):147-53.
  21. PMID 15609412
    .
  22. S2CID 45595812
    .
  23. S2CID 39360837
    .
  24. S2CID 22829613
    .
  25. ^ "EU/3/13/1208". 17 September 2018. Retrieved 1 June 2021.
  26. JSTOR 1549930
    .
  27. S2CID 8522101
    .

20. Young B, Lowe JS, Stevens A, Heath JW. Wheater's Functional Histology: A Text and Atlas. 6th ed. Elsevier

External links for general reviews
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