Dr Michelle Dickinson: nanotechnologist on the new research revealing gender matters in aging studies

For decades, most medical and biological research has been conducted primarily on male volunteers and male animals in laboratory studies. One of the main reasons was convenience - male hormone levels are more stable, whereas female hormones shift across the menstrual cycle, introducing variability that researchers historically preferred to avoid. 

But that convenience has come at a cost. 

When treatments are developed and tested mainly in males, the results don’t always translate well to female physiology. This means that women have often been prescribed medications or therapies that were never fully tested on their biology. In some cases, women have experienced more side effects, reduced effectiveness, or entirely different outcomes than men. 

As we learn more, it’s becoming clear that male and female bodies age differently too. And new anti-ageing treatments may need to take these differences into account. 

A new study published in the journal Ageing shows exactly why. 

The researchers discovered a combination of two drugs that extended lifespan in frail, elderly male mice by an impressive 73 percent from the start of treatment while also improving their mobility, endurance and memory. 

However, the same therapy did not provide the same benefits to female mice. 

They tested oxytocin, which is known to support tissue repair, along with another drug known as OT+A5i, which blocks a key pathway involved in regulating cell growth, differentiation, and death. 

The study involved 25-month-old mice which is roughly equivalent to a 75-year-old human. 

In male mice: 

• Lifespan increased by 73 percent from the start of treatment.
• Median lifespan increased by 14 percent.
• Risk of death at any time decreased three-fold.
• Endurance, grip strength, and agility improved.
• Short-term memory improved.
• Blood biomarkers shifted toward younger, healthier levels.

But in female mice: 

• No significant extension of lifespan.
• No consistent improvements in strength or memory.
• Blood biomarkers did not shift in the same way.

Researchers suggest several possibilities for the difference: 

• Female inflammatory signalling pathways differ from males
• Hormonal environments change ageing differently in men and women
• The interaction between oxytocin and TGF-beta networks may not play the same role in female tissues 

This highlights the point that ageing is not identical in men and women, and treatments to slow ageing may need to be tailored accordingly. 

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Episode Transcript

Speaker 1 (00:06):
You're listening to the Sunday Session podcast with Francesca Rudkin
from News Talks.

Speaker 2 (00:11):
It'd be well Science time now, Doctor Michelle Dickinson, good
morning to you.

Speaker 3 (00:15):
Good morning now.

Speaker 2 (00:16):
We have another interesting study and this is something we've
become increasingly aware of, but a lot of medical studies
are only done on men.

Speaker 3 (00:25):
So the reason why this has happened and it's only
really become like I've known about for a long time,
but it's because women are complicated. When you test something
medical on a human, there's already enough things going on,
what are they eating, what are their genetics? You don
want to add in hormonal cycles, and women are complex
because we have hormonal cycles. And so instead they go,
let's just take that variable out because our medication might

(00:46):
be based on where they are in their cycle. We'll
just do it on a dude. So it's always been
done on men until a very recently way we started going, hey,
you want to test those women drugs on women. Now
it's been really interesting because there's a new study that
came out this week in the journal Aging that basically
shows why you have to test on a whole wide
range of people. What they did is they were looking

(01:07):
at drugs that extend lifespan, and this has only been
done in mice. They don't get too excited. But they
took frail, elderly mice and they were twenty five months old,
but that's equivalent to seventy five year olds in humans.
And these mice looked old, they acted old, like they
were on their way out. And they basically discovered a

(01:28):
combination of two drugs that expended their lifespan by seventy
three percent from the start of the treatment, which is
interesting because often you go, oh, I should have been
taken this since I was young, blah blah blah. But
they just went, no, here, these super old, frail mice
have some drugs and they were like sprightly happy mice. Again,
so there's hope in the long run. Don't get excited.

(01:50):
It's only on mice increase their live span by seventy
three percent, and their risk of death at any time
decreased threefold. They had better grip, strength, better endurance, they
were running around like young mice. They remembered things, their
short to memory improved. But also importantly, they measured blood
bimarkers and those shifted towards younger, healthier levels great only

(02:10):
in the male mice, same drugs female mice, absolutely no difference,
absolutely not even any sign of improvement. So it would
have been very easy for a researcher to go, we've
found a cure. We're going to expand your life. And
previously we would only have tested it on male mice
first and then male humans. But like everybody date this,
but it would only have benefited the male because we
wouldn't have known. This is why we have to talk

(02:32):
about the importance of making sure we test things on
a variety of different people. Why is this, Well, they
actually dug into what was going on and they found
that the female inflammatory signal pathways differ in females and males,
and this was actually working on that inflammatory system. Hormonal
environments change aging differently in men and women and the interaction,

(02:53):
so this was an oxytocin based drug. The interaction between
oxytocin and the TGF beta networks, which is the inflammation ones,
do not play the same role in female tissues. So
this drug is amazing if you're a male mice. And
we just have to be really aware in the research
sector that we would have probably ten years ago made

(03:13):
the conclusion that we have got this drug and everybody
should have it, and the one would have taken it
and nothing would have worked. And if we had have
tested on female mice, which we don't because they're also complicated,
we would have known this. But it's a good reason
for us to make sure that we're doing good gender
testing in our drug research.

Speaker 2 (03:30):
Fascinating stuff, Michelle, thank you.

Speaker 1 (03:32):
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