Hi:
> I have recently been reading a lot about lipofuscin - the ubiquitous
>aging pigment which is found in many aging organisms. What is the most
>up-to-date
>info. on the content of this pigment and its source? I heard somewhere that
>a large fraction of the pigment was made up of a component of the mitochondrial
>ATP synthase. Is this correct?
This is an intriguing suggestion but I haven't come across any
corroborating evidence. Do you have a reference to this? Lipofuscins are a
range of fluorescent lipopigments. The following turned up in a Current
Contents search:-
VONZGLINICKI T (Reprint)
AU - BRUNK UT
AD - CHARITE BERLIN, INST PATHOL, SCHUMANNSTR 20-21, D-10117 BERLIN,
GERMANY (Reprint). UNIV LINKOPING, INST PATHOL, LINKOPING, SWEDEN
SO - ZEITSCHRIFT FUR GERONTOLOGIE 1993 JUL-AUG;26(4):215-220
AB - Oxygen-derived free radicals may result from various reactions, both
intra- and extracellularly, but generation of oxygen free radicals
from electrons escaping from the electron transport chain in
mitochondria is by far the predominant process during the lifetime of
a normal'', healthy cell.
There is clear evidence that mitochondria are also an important
target for oxygen-derived free radicals, and the resulting
mitochondrial malfunction has long been suggested as the
intracellular basis of aging. Moreover, there is clear evidence that
free radical-dependent reactions lead to lipofuscin formation and its
accumulation in Lysomes of post-mitotic cells. Lipofuscin
accumulation was demonstrated to be dependent on the probability of
iron-catalyzed Fenton reactions.
A hypothesis is presented which assumes free radical dependent
reactions in mitochondria and lysosomes to be interdependent.
Production of hydrogen peroxide in mitochondria and its subsequent
diffusion in the cytoplasm, and Fenton reactions in lysosomes,
transferring hydrogen peroxide intralysosomally to the highly
cytotoxic hydroxyl radical, are thought to be necessary intermediary
steps in the generation of mitochondrial damage. On the other hand,
damage to mitochondria increases both mitochondrial output of
hydrogen peroxide and lipofuscin accumulation.
Yours, virtually:-
Jim "Spermatology rules o~ o~ o~ o~" Cummins
Associate Professor in Veterinary Anatomy
Murdoch University,
Murdoch Western Australia 6150
Tel +61-9-360 2668
Fax +61-9-310 4144
E mail cummins at possum.murdoch.edu.au
