Re: Re: Human Embryonic Stem Cells
Tue, 10 Nov 1998 11:30:50 EST

In a message dated 11/10/98 12:47:13 AM, wrote:

>Thanks -- does that mean we could insert foreign mitochondria into mature

In theory, yes. But delivering foreign mitochondria is a fearsomely difficult task. They're big, they're numerous, and they're everywhere. Your best bet would be in giant cells like sensory/motor neurons and muscle fibers - which, fortunately, is probably where they'd be of most use. You'd need to introduce fixed or foreign mitochondria to an accessible spot on the cell and then provide it with a selective advantage over the residents. Of course, you don't want to harm all resident mitochondria as that would really harm cells that aren't infected (most, by almost any method) One idea would be for the introduced mitochondria to convert an administered drug into something toxic to other mitochondria.

>Is this a shortcut to rev up metabolism?

Not in general. Mitochondria only encode a very few proteins critical for aerobic metabolism. You're not going to be able to improve on them, and the control is from nuclear genes. You could use introduced mitochondria to replace damaged mitochondria in long-lived cells; accumulated mitochondrial damage is one hypothesis for the aging of non-dividing cells like nerves and muscle.