Organ transplants are a familiar idea. Organelle transplants, less so. Yet organelles are to cells what organs are to bodies—specialised components that divvy up the labour needed to keep the whole thing ticking over. Swapping old organelles for new in cells where the machinery has switched from ticking to tocking thus makes sense in principle. And, for one type of organelle, that principle is now being tested in practice.
Mitochondria, the organelles in question, are best known as power packs—places where glucose molecules are disassembled to release the energy that drives metabolism. Boosting a failing cell’s metabolic processes by adding new mitochondria could thus be a smart move.
But that is just a start. These organelles, the descendants of bacteria that cosied up with the ancestors of human beings back when those ancestors were unicellular, retain from their days of independence a list of other jobs. These include disassembling surplus fatty acids and amino acids, and synthesising haeme, the active centre of haemoglobin and several other proteins.
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Longing for longevity
One of the most intriguing findings of all, though, is that—in laboratory cultures, at least—transplanted mitochondria rejuvenate the biochemistry of elderly host cells. Given the number of free mitochondria in blood, this may help explain the puzzling observation that transfusing blood plasma from young to old animals seems to grant the latter a new lease of life.
This observation has long excited people seeking to prolong human “healthspan” to match the extended lifespans now enjoyed in rich countries. But the search for the elixir involved has hitherto focused on the plasma’s molecular cargo. Perhaps it is not molecules but mitochondria that would-be Methuselahs should consider. ■
Read the full story: Mitochondria transplants could cure diseases and lengthen lives (Economist)