‘Reversing ageing’ is the ultimate goal of the health and beauty industry today.
Advertising watchdogs, however, tend to take a dim view of claims that beauty products ‘reverse ageing’ and will demand for them to be removed – because there’s usually very little evidence to back them up.
Wrinkle creams might state they have ‘anti-ageing’ effects, but suggesting they actually turn back the clock on biology is considered a step too far.
Yet, whilst we humans may not be able to press rewind on life, jellyfish can. Or rather, at least one type of tiny jellyfish: the ‘immortal jellyfish’ (Turritopsis dohrnii).
Like a pea-sized, wibbly-wobbly Doctor Who, Turritopsis has the power to regenerate itself when mortally wounded. But instead of a dramatic, colourful explosion like the Doctor, the jellyfish does it by settling down on a surface, sucking its tentacles back in and quietly turning itself into a blob.
This blob becomes the jellyfish’s ‘polyp state’ – an earlier part of its lifecycle that Turritopsis can revisit to produce brand new jellyfish. The new, genetically identical jellyfish simply bud off, separating to becoming an entirely independent creature.
Immortal jellyfish are the only animals known to be capable of this feat, and even then they’ve only been observed doing it in captivity. When their abilities were discovered in the 1980s, scientists were flabbergasted.
Hang on a minute, though, you might say. We do something equally impressive when we make babies, don’t we? The immortal jellyfish isn’t repairing its own body, as such – it’s spawning a bunch of new ones from the old one.
Human babies also come from an old part of us: an oocyte (egg cell) that has existed since we were born. And our embryos are still considered ‘new’. So, in a sense, we’re both able to regenerate from our own cells.
One big difference, of course, is that our babies aren’t clones of us.
That’s because we can only form a new organism by combining our egg DNA with a coordinating set from a sperm. Immortal jellyfish in their regenerative state, meanwhile, don’t need sperm – even though that’s their usual preference.
Arguably, then, the new jellyfish are ‘babies’ rather than the same animal regenerated. But they’re still perfect copies.
And what’s more, the ‘parents’ are doing it by rewinding to a state where they can make ‘babies’ again, which is somewhat akin to reversing menopause. Plus, they can do it quickly enough to cheat death.
Overall, their special powers suggest there’s at least some biological plausibility to the concept of reversing ageing.
And scientists continue to study immortal jellyfish in the hope of learning their secrets and using them to treat ageing conditions like dementia.
In one 2022 study, Spanish researchers found that compared to other, related jellyfish, immortal jellyfish have more active genes involved in repairing DNA, preserving telomeres – the tips of chromosomes that wear down with age – and maintaining stem cells, which are needed to regenerate tissues.
Whether these discoveries will help humans to reverse ageing, or, ultimately, cheat death remains to be seen.
This article is an answer to the question (asked by Jacqui Brock, Massachusetts) 'Can we actually reverse ageing?'
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