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Comment by T-A | Hacker News Reader

It occurs to me that mitochondrial decline also seems to be an important aspect of aging. If you can just infuse mitochondria through the blood and "the organelles will gravitate almost magically to the injured cells that need them and take up residence", that suggests a rather obvious rejuvenation approach.

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Yeah, Mitochondria are a big deal in aging. Animals of a given size with larger mitochondria populations, like hummingbirds, tend to live a lot longer than other animals of similar size. Though hummingbirds lose their ability to hover and hence feed normally in the wild long before they die of old age.

Nick Lane wrote about book about mitochondria I'd heartily recommend: Power, Sex, Suicide: Mitochondria and the Meaning of Life.

EDIT: And Aubrey de Grey of course has a typically audacious/crazy plan for dealing with mitochondrial mutations. http://www.sens.org/research/introduction-to-sens-research/m...

Yup. It is a very promising area of rejuvenation research. I think right now most dollars are allocated to understanding basic mitochondrial function. As well as cures for the pernicious degenerative diseases associated with malfunctioning mitochondria that cruelly tend to develop in young children. But there is no question: further research activities and clinical trials have a high probability of bearing fruit. Cryo-EM visualization of metabolic pathways. Even understanding function and purpose of the THC cannabinoid receptors found on their outer membranes could unlock their mysterious hidden potential.

But where do we get those new mitochondria from? I'm almost afraid to ask.

Maybe from cloning one's own cells, then carefully dismantling them to free up mitochondria without damaging them? I don't think a lot of the tissue should be required (that is, ounces, not pounds).

mitachondria are living organelles, they could simply be induced to replicate until the desired quantity is reached.

If I recall bio from school, they are super adapted to living in animal cells -- they probably couldn't survive on their own.

It's true that they very much rely on a nuclear genome, because some of their genes required for independent replciation have been lost. But surely there's a framework that enables the mass replication of mitochondria using our own cells as a source material.

I doubt blood would work because red blood cells contain effectively very minimal, if not zero, mitochondria (depending on stage of cycle).

Funny enough, the best bet might be taking mitochondria from sperm or egg. Human sperm have ~50-75 mitochondria per cell. There's on average 50 million sperm cells per ml of ejaculant and the average is 2.5ml per ejaculation, so 125 million mitochondria could potentially be harvested from an average guy in a single go, provided the extraction is an unrealistic 100% efficiency.

50 million/ml x 2.5 ml x 50 = 6.25 billion, is what I get the number to be.

Ah yes, I totally botched the math. Thanks for that.

So 6.25 billion potentially harvestable mitochondria per average sperm donation.

Hard to say how much might be needed for a rejuvination test, but those seem like viable numbers.

If adipose cells could be used for this purpose, a small amount of liposuctioned fat would be adequate.

And if pounds are needed, well... let's just say there should be plenty of eager donors for those who don't have enough.

http://www.lifeextension.com/magazine/2010/ss/rejuvenate-you...

http://www.lifeextension.com/Magazine/2010/2/Reverse-Mitocho...

And do different cross have different mitochondria? I would be tempted to say no but I'm not sure

All the cells in the body have the same mitochondrial DNA, which is inherited from the maternal side (egg cells have them, sperm cells don’t).

(Edit: except for cells that have no mitochondria, of course)

Yes but do they differentiate across different cell types?

IANABiologist, but my understanding is that they don’t differentiate; they have too simplistic a structure for that, and rely on the host cells for many of their functions. The main differences seen across cell types is whether they are present or not.

My girlfriend is a biologist. She is saying that all cells that have mitochondrias in a human body have the same mitochondrial DNA.

Truly, they are the powerhouse of the cell

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