Is there an elixir of eternal youth for pets?
LULU, a fifteen year old terrier, is often mistaken for a puppy: her coat is shiny, she’s active, and she likes playing. Meanwhile Hattie is just two years old, but her black muzzle is tinged with grey, and people think she’s an elderly dog. The signs of ageing in pets vary significantly between animals, just as they do between humans.
I have always been intrigued by the fact that pets age at such a different rate from humans. I know from my veterinary studies that animal tissues look remarkably similar to their human equivalents under the microscope. Cat kidney cells look just like dog kidney cells which are very similar to human kidney cells. And the same applies to most parts of the body. Yet here’s the paradox: animal bodies get older much more rapidly than human bodies.
It starts when they are young: puppies and kittens are helpless at birth, just like human babies, but by the age of four weeks, they are fully weaned and able to run around. In contrast, the average human isn’t able to walk till they are a year old, and some take even longer, which is at least twelve times longer than animals take to get going. Pups and kittens are ready to leave their birth families by three months of age: most humans aren’t mature enough to leave home till their early twenties, which is eighty times longer in real time. And typically, a dog or cat reaches terminal old age at the age of fifteen or sixteen, while humans now often live into their nineties, or six times longer than pets.
And each part of the body ages more quickly: a fifteen year old dog or cat’s mouth is usually missing teeth, with advanced periodontal disease, while a fifteen year old human’s teeth are shiny, youthful and white. The joints of an aged dog or cat look just like the joints of a person in their eighties: advanced arthritis is common.
Wouldn’t you think that since we all look the same under the microscope, we all have similar chemicals and cells in our bloodstream, and the same type of essential life force, that we would all develop and grow older at a similar rate?
One of the interesting areas of contemporary science is the study of ageing, known as gerontology. Or perhaps it’s more accurate to say “the study of anti-ageing”, because that is the real reason why many people are involved in this research. Unlike animals, we humans have enough self-awareness to know that our lives are limited, and we realise that our death is inevitable. Many of us have a hope or expectation that life continues beyond the grave in some form, but this has yet to be scientifically proven. It’s fair to say that as far as science is concerned, life stops at the point of death. And most humans would prefer this not to happen: we enjoy being alive. So we are fascinated by a science that promises the possibility of helping us live for longer.
Humans can now buy a wide range of anti-ageing products: yoghurt cultures to reseed our gut microbiomes, enema regimes to tackle our innards from the opposite end, cell injections to reinvigorate our ageing organs, magnetic devices to realign our tired tissues, and skin creams to smooth our wrinkles. We can try herbal elixirs, vitamin supplements, specialist diets and intricate exercise programmes. But do they work? The people selling their products enthuse while the scientists mutter about over-commercialisation of ideas that are just at the concept stage.
So what do scientists really think causes ageing? There are four main factors. First, toxic substances accumulating inside cells. Second, gradually worsening cell damage caused by ionizing irradiation, free-radical metabolites and environmental pollutants. Third, changes caused by an over-active or under-active immune system. And fourth, genetically preprogrammed cell death started by a part the gene that dictates for the cell’s lifespan. Every cell is genetically preprogrammed for a specific number of cell divisions: then it will die . It seems to me that this is the main area where animals differ to humans: the ultimate fix for old age in pets, as in humans, would be to identify the age-limiting genes, and to use genetic engineering technology to splice on a replica gene which doesn’t include the end-of-celllife programming. Perhaps in the twenty second century, this is that may be introduced- for people and for pets.
Until then, if you want to live as long as possible, humans need to focus on issues like diet, exercise, sleep and mental health. What about our pets? The five most common causes of death in older dogs are cancer, cardiovascular disease, and kidney failure, epilepsy & liver disease. In cats, the top four fatal diseases are cancer, kidney failure, cardiovascular disease, and diabetes mellitus. So it makes sense to look out for the early warning signs of these common and serious life-shortening diseases in older pets, so that early and effective treatments can be given. A thorough check up by your vet, every six months or so, is the best way to make sure that you are not missing any clues.
And then just as for humans, physical and mental exercise, special senior diets and perhaps antioxidant supplements, are the combination that offers the best hope of helping our pets live for as long as possible. Life has to end some time, but for pets and people alike , later is better than sooner