lipofuscin

Dr Jim Cummins cummins at POSSUM.MURDOCH.EDU.AU
Sun Nov 6 21:31:33 EST 1994


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








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