Of Mice and Old Men: Silicon Valley's quest to beat ageing

To understand what's happening in the tech world today, you need to look back to the mid-1800s, when a Frenchman named Paul Bert made a discovery that was as gruesome as it was fascinating.

In his experiment, rodents were quite literally stitched together in order to share bloodstreams. Soon after he found the older mice started showing signs of rejuvenation: better memory, improved agility, an ability to heal more quickly. In later years, researchers at institutions like Stanford would reinforce this work.

The extraordinary technique became known as parabiosis, and forms the basis of efforts at Alkahest, a California start-up that is banking on being able to apply those rejuvenative effects to people, rather than mice. It's an idea so fantastical it wouldn't look out of place in an episode of Silicon Valley, the HBO send-up of the start-up scene.

And to all intents and purposes, it was. Season four, episode five. During a meeting, tech executive Gavin Belson introduces young Bryce... his blood transfusion partner that would keep him young.

Like so much great comedy, Silicon Valley hits the right spots because it rings true. Alkahest is providing the Bryce to real life Gavin Belsons through the movement of blood plasma, obtained by young donors all over the world.

Blood of our youth

"Silicon Valley luminaries are looking at their old form as they get older and thinking, 'What can I do about this?'" said Kristen Brown, a biotech journalist for technology news site Gizmodo.

"It's the classic Silicon Valley mindset: 'How do I hack this problem?'"

For this week's episode of Click, I was given the task of trying to make sense of this desire to stretch our lifespans, or at least our health span - the number of years we remain fit and able before the troubles of old age kick in.

Some measures - like sucking the blood out of our youth, for instance - are at the more dramatic end of the scale. But elsewhere in the "longevity space", as I heard it called, we see something more low-key, backed up with something at least approaching a scientific consensus.

So I decided to start there. HVMN - pronounced human - is a start-up that encourages smart fasting. It is of course something that humans have done for thousands of years, but it's only in our more recent history that we've understood more fully how the body reacts, and more importantly, what it produces while we're deep into a fast.

Beginning on a Monday night, I started the Monk Fast - 36 hours in which I could only drink zero-calorie liquids. In my case, that meant a diet of just water and black coffee.

"My advice to you is sleep in really late so you don't have to deal with it," Ms Brown joked.

Here come the ketones

Staying in bed wasn't an option. The following morning I skipped breakfast (for the first time in years) and met Geoffrey Woo, chief executive and co-founder of HVMN.

The company focuses on products Mr Woo claims can boost the effects of fasting. According to the company's Biohacker Guide, there is a "growing body of scientific research" that showed "health benefits including longevity, improved metabolic state, improved insulin resistance, and cognitive improvement".

Mr Woo says depriving yourself of nutrition provokes the body to produce ketones, a byproduct of your organs turning to your stored fat for fuel.

"As one gets better at being in ketosis," he told me, "it becomes a productivity boost."

The UK's NHS has warned about ketosis as a result of a low-carb diet which can be linked to headaches, weakness, nausea, dehydration, dizziness and irritability.

To help with my own fasting, I tried one of HVMN's products, a "super fuel drink" that is supposed to almost instantly get my body to start producing ketones at a level that would ordinarily take several days of fasting, not the mere few hours I had achieved by that point. To begin, we did a quick blood test to measure the current level of ketones in my body. It was low - 0.2 millimolar.

The $30 (£21)-a-pop supplement - officially classified as a food by the US regulator - came in a small plastic bottle that in a former life might have held cheap aftershave. I unscrewed the top and knocked back the substance like a shot of suspect liquor, going back for a second effort to finish off the last drop. HVMN has valiantly tried to mask the smell of it, but it could do little about the bitter, sharp taste.

Some 30 minutes later, we repeated the test. I didn't feel remarkably different, but my ketone level suggested otherwise: 2.2.

"It's the equivalent to having fasted for three or four days," Mr Woo explained.

'Lunacy'

The question is: do I believe him?

In the run-up to filming our story, I'd read about how HVMN apparently hid away a report it had commissioned into the effects of Sprint, another one of its products. The unfortunate conclusion was that it had little effect on alertness beyond that of a strong cup of coffee. Headlines at the time suggested the company did what it could to stifle the report's publication, but Mr Woo insists that wasn't the case. Indeed, the company now links to the study - which Mr Woo co-authored - on its website.

To find out more, I drove to the Buck Institute for Research on Aging which is based in the beautiful city of Novato, near California's wine country. It's the kind of place that would make you want to live as long as possible.

Here I met Dr Eric Verdin, one of the world's foremost experts on the science of ageing.

"Fasting elicits a response in your body that triggers a protection against many of the diseases that are associated with ageing" he explained.

"So there's growing realisation that multiple forms of fasting might actually be beneficial in the long term. The science is really strong in this area."

He was less persuaded by Alkahest's claims of using young blood to rejuvenate the old.

"First let's talk about science in mice. It is amazing work, the science is strong.

"Taking this and bringing it to humans is a completely different story. The idea that one would take human plasma and give it to humans to prevent ageing is, in my opinion, lunacy."

Trials ahead

But to be clear, Dr Verdin's concern with Alkahest, and other companies like it, was mostly about safety and risk of infection, owing to the current process this technique requires today.

As for the possibility it would work, he says we simply don't know.

Alkahest chief executive Karoly Nikolich is confident but acknowledged the lack of solid science.

He told the BBC that a small study of 18 people suffering from early-stage Alzheimer's had shown positive results. Once a week over four weeks they were each given one unit of plasma taken from, probably, a student aged 18-30.

Over time, Mr Nikolich said those patients showed a better ability to perform basic daily tasks, and were more aware of their surroundings and sense of self.

But anecdotal evidence on how someone feels and acts is hardly conclusive. A more formal study presented by the company to an Alzheimer's conference in Boston last year couldn't even prove minimal benefits.

The company is pressing ahead, buoyed by other academic studies that built on Paul Bert's work and discovered that something in young mouse blood can fight Alzheimer's in the older mouse - they just haven't figured out what it is yet.

Spanish medical company Grifols recently invested $40m in Alkahest, and as a result will be a partner as it solicits blood donations from young people all over the world to be used in longer, more far-reaching studies.

The holy grail in this industry would be discovering specifically what can fight ageing - and bottling it.

"Ultimately we might be able to identify agents that could be administered orally," Mr Nikolich said, while predicting it might take more than a decade.

Breaking fast

By Tuesday night, my own attempts to reverse the ageing process had left me feeling 20 years older. It was over 24 hours since my last calorie, and I was struggling.

I'd spent the evening at the cinema after a friend suggested - incorrectly - that it would take my mind off food.

What I found was that while fasting my mind became unable to process multiple inputs at once. After parking and getting out of the car, I started walking towards the cinema - only for my friend to point out that not only had I not locked the car, but the engine was still running.

By Wednesday I felt a little better, but still uneasy on my feet. My 36 hours were up, and after inhaling pancakes at one of Oakland's finest breakfast spots, I came to the conclusion that while scientists may be learning that fasting can indeed give you a longer life, there's no way they can convince me it'll be a happier one. You're not you when you're hungry, as the slogan goes.

My own rumbling tummy aside, is Silicon Valley on course to achieve its goal?

"We see the body as a platform to innovate," said Mr Woo, but Mr Verdin sees tech's contribution slightly differently.

"They're bringing incredible resources," he said

By which of course, he means cash. There's oodles of it pouring into this - and of all the daft ideas backed in this part of the world, I guess living longer and being healthier is something worth putting some money behind - lest we start stitching teenagers to billionaires.