Cats a clue to development of Alzheimer's in humans

Published on 06/12/2006 00:37

ELDERLY cats - particularly lonely, bored and badly fed ones - can develop a form of dementia "remarkably similar" to the human kind, researchers say.

The discovery could help scientists develop treatments for humans and cats - partly as cats' shorter lifespans make it easier to uncover environmental factors behind the disease.

In humans, a protein causes "tangles" inside nerve cells that hinder messages processed by the brain. The academics found it did the same in cats' brains.

While the differences in cat and human physiology mean felines are unlikely to be used in tests, studying pets that develop the disease could advance understanding of the condition in humans. Drugs could also be trialled on cats which would otherwise be put down because they were so badly affected.

Dr Danielle Gunn-Moore, a cat expert at Edinburgh University's Royal (Dick) School of Veterinary Studies, whose husband, Frank, works on Alzheimer's disease in humans at St Andrews University, said she began to investigate the condition when their pet cat, Cardhu, developed dementia at the relatively young age of eight.

"We've known for a long time that cats develop dementia, but this study tells us that the cat's neural system is being compromised in a similar fashion to that we see in human Alzheimer's sufferers," she said.

"The shorter lifespan of a cat compared to humans allows researchers to more rapidly assess the effects of diet, high blood pressure and prescribed drugs on the course of the disease."

It is thought that nearly a third of pet cats aged 11 to 14 have at least one age-related behavioural problem and this increases to more than 50 per cent for cats over the age of 15.

However, elderly cats and owners can help each other avoid dementia.

"If humans and their cats live in a poor environment with little company and stimulation, they are both at higher risk of dementia," Dr Gunn-Moore said.

"However, if the owner plays with the cat, it is good for both. A good diet enriched with antioxidants is also helpful in warding off dementia, so a cat owner sharing healthy meals like chicken and fish with their pet will benefit them both."

Signs of a dementia in cats include losing litter box training, becoming "clingy" or aggressive, being unable to recognise their owner, wandering aimlessly and crying at night.

High blood pressure, kidney problems and other diseases affecting the circulation, which are potentially treatable, can lead to dementia.

A cat's purring has been shown to reduce blood pressure and promote bone healing.

Dr Frank Gunn-Moore said: "It has given us an insight into molecular changes in the degenerating brain. From this we are trying to develop treatments to help cats and humans."

PLAY MAKES FELINE FINE

ELDERLY cats might seem less interested in playing than when they were younger, but it can stave off dementia in the same way as crosswords and Sudoku puzzles help humans.

While owners should not wake up their elderly pet and insist it engages in strenuous activity, games can help keep them mentally active.

Cat counsellor Vicky Halls said: "We are talking about stimulating the cat's brain, the natural processes and behaviours, to make sure the cat continues to use the parts of the brain that it would use normally.

"By far the easiest way to do this is to encourage the cats to play, problem-solve and to have a degree of simulated hunting."

This can be done by wrapping up food in greaseproof paper so the cat has to unravel it or by hiding a biscuit inside a cardboard box, for example. "Fishing rod" games, using feathers or perhaps a favourite treat as bait, can also be used.

"The cat is not going to leap about, but even if the cat just moves its paw [that's beneficial]," Miss Halls said.