“Why are cats so vulnerable to kidney disease?”
It’s a question that anyone looking after a cat has asked themselves at least once during their lives. Now, thanks to the research of Dr. Toru Miyazaki and Dr. Toshiro Arai, we may be closer to the answer. A paper by multiple authors, including the two aforementioned doctors, reveals certain properties of the AIM protein in cats that may hold an important clue.
AIM Says “It’s Time to Clean!”
Think of the AIM protein as an alarm clock for your cat’s kidneys, one that rings when the kidneys need cleaning. When your cat is healthy, the ‘alarm clock’ is safely stored inside a ‘container’ known as IgM within your cat’s blood, where it stays dormant.
When the kidneys take damage, the ‘alarm clock’ separates from its ‘container’ and travels to the kidneys, telling the janitors to clean up the waste accumulated in the renal tubules. At least, that’s how it’s supposed to work.
The problem is that in cats, the ‘alarm clock’ doesn’t quite function the way it does in other animals. It’s bound too strongly to the ‘container’, preventing it from detaching and doing its job.
What’s Wrong with AIM in Cats?
An easy way to understand the issue with a cat’s AIM proteins is to just imagine that the ‘alarm clock’ has somehow been superglued to the ‘container’ it's kept in. The connection between AIM and IgM in cats is approximately 1,000 times stronger than the connection between them in humans and mice.
No matter how much damage the kidneys take, the ‘alarm clock’ cannot take off to tell the janitors to get to work cleaning things up. It simply stays in place, unable to metaphorically sound the alarm.
Blockages in Renal Tubules
Renal tubules are small tubes in the kidneys that filter waste from your blood, and must be kept clean for your cat to urinate properly. However, as AIM in cats cannot signal cleanup in the kidneys, the tubules continue to accumulate waste, causing a blockage.
This prevents the kidneys from functioning properly, and may lead to acute kidney injury (AKI). If the cause is left untreated, AKI can even lead to chronic kidney disease (CKD) in cats.
Understanding the Role of AIM
In order to understand the issues posed by feline AIM, Dr. Toru and Dr. Arai conducted an experiment in which feline AIM was injected into mice. The results of the tests on AIM felinised mice were as follows:
<Comparison of CRE Levels and Survival Rates in Wild-type and Felinised Mice>
In AIM felinised mice, AKI was induced and waste could not be removed from the tubules, leading to death in all cases of felinised mice within 3 days. In addition, no recovery was apparent in the brush border in the proximal tubules of the AIM felinised mice.
However, when feline recombinant AIM (rAIM) was administered, the results told a different story.
<Comparison of CRE Levels and Survival Rates in AIM Felinised Mice and rAIM-injected Mice>
In mice who had been injected with rAIM, the renal tubules were cleaned, and their survival rates increased all the way up to 80%.
What Does This Mean for AIM Treatment?
Proper use of AIM can protect the health of not just a cat’s kidneys, but their overall health. This research was able to uncover the reason for feline vulnerability to kidney disease, as well as suggest a potential for AIM-based treatment.
As such, we have high hopes that AIM can help prevent and improve AKI and CKD in cats.
