'Are you noticing things falling apart a bit as you're getting older? ' asked presenter Dr Kat Arney, as I tune into the Genetics Society podcast. This personal attack almost makes me spill my hot cocoa and fall off my lumbar support (I'm 28 and it's a lockdown Saturday night). This is going to be a bumpy listen.
Dr Arney is the hilarious and relatable author of 'Rebel Cell', a book about cancer. She begins by chatting with computational biologist Dr Andrew Steele, author of the book 'Ageless'. For starters, what is ageing? For an incredibly complex biological phenomenon, the simplest definition is statistical. The rate of ageing is the rate at which your risk of death increases throughout your life. In humans the risk doubles every seven or eight years. In mice this happens in months. In Galapagos tortoises, ageing is negligible – their risk of death is constant no matter how long ago they were born.
Cancer-specialist Dr Arney immediately highlights the link between cancer and ageing. Why does ageing predispose you to a load of other diseases, including cancer? The answer is not just through accumulated DNA mutations but through a 'paranoid and ineffective' immune system. In the spirit of the modern era (remember #covfefe?), Dr Steele has even coined a new word – 'Inflammaging'. Nothing to do with the rage induced by influencers, it means the accumulation of senescent (ageing) cells in the body. They emit a toxic cocktail of molecules – killing us from the inside – while trying to call to the immune system for help. But there is good news! Drugs have been developed that can kill the senescent cells selectively. Preclinical research on mice has shown that they are able to keep the mice wrinkle-free with lustrous fur. Human clinical trials are currently underway in patients with age-related diseases, such as arthritis and lung fibrosis.
But enough about drugs, what about genes? To understand ageing genes, we have to talk about worms. A tiny mutation in the gene age-1 can extend a worm's lifespan ten times. Does this translate to humans? Yes, and no. Interestingly, only ten to 20 percent of our lifespan is heritable. The rest is down to lifestyle and luck – for most people. But there are some 'super-lifers' among us – and their lifespan is genetic. If your parent lived to 100, you are 10 times more likely to live a century compared to the average person. These super-lifers have pushed ageing back ten or 20 years. 'I'm too busy to be old right now, I've got stuff to do' Dr Arney summarised.
For a deeper dive into the genetics of ageing, Dr Arney also speaks to Dr Raheleh Rahbari, a cancer research fellow at the Wellcome Sanger Institute in Cambridge. She tells us that ageing is not the same in different parts of the body. For example, the colon accumulates mutations at a higher rate than testicular tissues. Evolution has kept mutations lower in the reproductive tissue and protected it so that fewer mutations are passed down to the next generation.
How will anti-ageing research affect society? Look at it this way – if we could completely cure all cancer, it would only add about two years to life expectancy. Same goes for heart disease. Picking off individual diseases is not effective, but anti-ageing research could defer all of these diseases simultaneously. But with that promise comes a lot of false advertising. The podcast warns us against some 1920's quackery (monkey testicle grafts), but doesn't mention the anti-ageing pseudo-science that is blighting the 2020's (unlicensed stem cell treatments, anyone? (see Bionews 1031).
My favourite part of the podcast was the short list of scientifically-backed anti-ageing tips – including living a healthy lifestyle, and brushing your teeth. When you have gum disease, there is chronic inflammation in your mouth, which can accelerate heart disease, cancer, and possibly even dementia. With all this evidence, 'I'm prepared to take the risk and brush my teeth' said Dr Steele.
I thought this Genetics Unzipped episode was excellent, fitting a lot of information into a mere 35 minutes. Of course, some ageing facts were left out, in particular research into the link between the mTOR gene, fasting and ageing (see Bionews 720), but the podcast conveyed some excellent real-life tips. Now, if you'll excuse me, I need to go and brush my teeth.