[00:00:00] Introduction: Welcome to All Cats Considered, a podcast from the Feline Veterinary Medical Association.
Here we interview professionals from across the veterinary world and take deep dives into the latest evidence-based research developments, studies and guidelines that improve feline health and well- being.
We are the home for veterinary professionals seeking to enhance the care of cats through high standards of practice, continuing education and evidence-based medicine. In each episode you'll hear interviews with a variety of experts in our field covering a wide range of topics and the latest developments in feline health. We'll share the key points you need to know to improve your patients' care.
Let's dive in and listen to this week's experts.
[00:00:47] Gómez-Mejías: Welcome to another episode of All Cats Considered. I'm Yaiza Gómez-Mejías, Veterinary Community Coordinator and today we have the pleasure of interviewing Marge Chandler, who most of you probably know because of her prominent role as a veterinary nutritionist. She has recently written a JFMS Spotlight article on sarcopenia, cachexia and frailty in older cats which she will talk about today. Welcome Marge and thanks for joining us.
[00:01:14] Chandler: Thank you so much Yaiza, for the opportunity to discuss this very, very important topic for cats. I think this is going hopefully change things in the way that we practice.
[00:01:25] Gómez-Mejías: Always lovely to see you and I'm really looking forward to this interview.
May I start asking you, do both sarcopenia and cachexia include low muscle strength? How is one different from the other? And why are these things so important in older cats?
[00:01:43] Chandler: They both probably include low muscle strength. That's a little bit hard to measure in cats right now. We don't have a good way of measuring that in cats. In people, they do things like grip strength and the ability to get out of a chair. Cats don't necessarily agree to doing these kind of tests, but certainly with the low muscle mass, with the decrease in muscle mass that is associated with these, I would expect that we definitely see a change in muscle strength as well. The definitions of sarcopenia and cachexia differ slightly. Sarcopenia is considered to be muscle loss generally associated with weakness in aging cats, humans, horses, mammals of all kinds. It's thought to be an overall concept, at least in mammals. I don't know about reptiles or birds, maybe those species as well.
This is considered to be not, I guess, sort of a normal aging change. Maybe a common aging change would be a better way to say that. Cachexia is the muscle loss associated with inflammatory mediators due to illness, sometimes injury, but really more with illness, chronic illnesses, heart disease, renal disease that go along with that. You know, I was thinking earlier about this. Does this include osteoarthritis? This is a disease, and I guess it kind of could, which means the majority of our cats probably have a degree of cachexia. These both overlap. The one doesn't eliminate the chance of having another. I think probably most older cats who have cachexia due to a chronic disease would also have sarcopenia, so they certainly can be combined. And I think that's probably a very common feature. Certainly in older humans, that can be a common feature too, to have both of these. One of the differences between them is with cachexia, the muscle loss can be more profound and more rapid. So I think when we see this in an older cat who's kind of gone downhill, so to speak, as far as strength, that we certainly need to look for something more than an aging change.
[00:03:51] Gómez-Mejías: And you mentioned frailty as well.
What is frailty?
[00:03:55] Chandler: I think frailty is the measurement that we really need to be considering now. Muscle loss.
A veterinarian or owner might say, yes, okay, there's muscle loss, but so what? How is this meaningful?
To me, the meaningfulness about muscle loss is frailty. Frailty has been defined as a loss of physiological reserves in humans. It's not a definition I particularly like, because what does that mean, physiological reserves? This is how it's often used. I think a better way of looking at that is a loss of physical and cognitive performance.
This is the signs that we actually see in an older human, an older cat. A lot of the research is in humans, so I will kind of reference that a lot, because we don't have as much research as we should have in cats. But the cat who no longer wants to jump on the counter, the cat who forgets where his food bowl is, or yells all night. We certainly recognize that as a, as a cognitive problem in some older cats, these go along with frailty. And the muscle loss certainly affects the physical performance of the cat. I know we don't often think of cats as performance animals, but their ability to play, to get around, to run up the stairs, to get to their food and water bowls so frailty is a prominent feature of the quality of life.
There was recently published a pilot study on looking at developing a frailty scale, an index scale for cats. We've had two or three of these for dogs, several for humans. And this, I think, will give us a great tool going forward on being able to assess frailty in cats and, and understanding its meaning for owners. It's an assessment both from, from owners and for vets. And this gives us a great tool to assess, I think the functionality of looking at that muscle loss in cats.
[00:05:55] Gómez-Mejías: At what age roughly do we expect these changes to start occurring?
[00:06:00] Chandler: That's a great question because we don't have good information on that for cats. Most of the studies, including the frailty index score looked at cats. That was cats aged 11 to 20. There's been other studies looking at muscle loss in cats that were 12 to 15 years old. And we know in a 15 year old cat that a lot of those have lost about a third of their lean body mass at that age.
But it probably starts a lot earlier. We don't know this, it hasn't been looked at in cats. In humans, depressingly, muscle loss actually starts at around age 30, affecting a lot of us. It's a small percentage each year, but this would be maybe a five or six year old cat might to have a little bit at that time. Now can we assess this? Probably, certainly not yet. We don't have the tools to assess that, but we will probably need to look at that at some point.
In humans there is an acceleration of the muscle loss at around age 60 to 65, which would be again roughly the 10 to 12 year old cat. So this is probably when the loss becomes more profound due to sarcopenia alone. A cat of any age of course could have cachexia, could have an illness, chronic illness, that will cause the muscle loss potentially much earlier if they're younger, when they get kidney disease or another debilitating disease. Certainly something we need to maybe start considering more than just thinking about, "Oh, the thin old cat."
[00:07:31] Gómez-Mejías: My cat, I had to euthanize him when he was 17.
He had experienced some muscle loss, but the day before I put him to sleep, he was jumping onto the counter and he had developed a pleural effusion. So he was really poorly. But still you could see the muscle waste. I guess they develop ways to counteract that relative weakness as well and that may contribute to the barriers that we have to, to detect it.
[00:08:07] Chandler: Sure, that's a really good point. I certainly had an older cat who'd had lymphoma, laryngeal lymphoma when he was 16 and was happy until two days before he developed respiratory problems. What we need to remember is as with humans, there's a great variation in cats. I'm speaking as though this is general. All of them are affected by it, sort of. All of us are affected by a degree of sarcopenia as we age.
But you know, I've got a 70-year-old friend who runs marathons. There's a, there's a big difference in a 70-year-old human friend.
There's a big difference in, in how it affects individuals and a big difference in our own, I think mental and physical resilience to it and determination to continue. And so there's a lot of individual variation in that which might be what you were seeing in, in your older cat is that, you know, he was able to overcome that in some way.
[00:09:03] Gómez-Mejías: Another term you mentioned in your article when you write about aging is anabolic resistance. What does this consist of?
[00:09:10] Chandler: Anabolic resistance is an interesting concept. It's not proven in cats, but is likely it happens in other mammals, certainly humans and rodent studies in that with age due to changes in various hormones and cytokines and other metabolites such as IGF1 growth factor or insulin like growth factor 1, which is a reflection of growth factor. That the muscles are less responsive to being able to assimilate and utilize amino acids so that it takes for an older human more protein to synthesize muscles than for a younger individual.
So years ago, I know this is still sometimes a concept. Years ago we used to always say older animals, older cats should have a decrease in their protein intake. We had an incorrect idea then that this would prevent renal disease, which it does not. And it's possible that older individuals need an increase in protein or possibly an increase in some specific types of amino acids.
I don't know this yet. In cats, I think it's still certainly an area that we need to explore if we can help support their muscle mass and function by these types of changes in diet.
[00:10:33] Gómez-Mejías: Are there any risk factors that we think that would increase the likelihood of sarcopenia and is it associated with anything else we may often find in older cats?
[00:10:45] Chandler: Yeah, for sarcopenia. If we look at this, I think decrease in activity in humans is certainly associated with loss of muscle mass and function. As a risk factor, I don't know how we fit this in, aging is the risk factor and that one's hard to prevent. But certainly poor diet, lack of exercise are recognized in humans as increasing frailty as well as sarcopenia that you're. The less you do, the less you'll be able to do. So we do need to encourage treatment for osteoarthritis, any other mobility problems that the cats have. We need to encourage owners to continue to play with their older cats to keep them active, whatever that takes. We need to with their activity, take into account that they may have some discomfort, for example, with interactive feeders, which are an excellent idea. We might want to have the cats use their paws a little bit less if their elbows are sore, but still to keep them active, maybe in seeking food and using mats and in being able to look around the house in ways that are comfortable for them. Cats are hard to exercise. We can't take them out. Well, some of them unless they're leash trained. We can't really take them for walks as well as we do with dogs, but we do need to consider their activity levels along with their diet and feeding management.
[00:12:04] Gómez-Mejías: Knowing how relevant muscle condition score is, this podcast hopefully will encourage some vets to comment this to their colleagues. Which are the most common barriers, do you think we find to evaluating and interpreting muscle condition scoring as part of the physical exam?
[00:12:22] Chandler: This has been a frustration for us on the muscle conditioning score in WSAVA when we when we published nutritional assessment, which includes muscle condition scoring along with body condition scoring. I think there's a couple of things that it hasn't been taken up nearly as well as body condition scoring, and there are a couple of things that probably have affected this. Vets feel unsure how to do this. They feel like they don't know how to do it even though it's described how to do it.
When we developed the four, the four sort of stages of muscle normal to severe loss, there was a discussion of having that as a binary - yes, no. Because my moderate might be your mild and it's validated, but not as well validated as is the body condition score. So one, they feel a little unsure that they know what they're doing. And my response to that when I lecture is it doesn't matter if you don't feel like you know what you're doing, just write something if you think it's there. And again, evaluating over the lumbar muscles is probably a good place to start in most cats.
Secondly, it's sort of a what do I do with this information? It's a little harder to know of an intervention for muscle loss for vets in practice right now. If they have an overweight cat, they know what needs to go on our diet to get rid of the body fat. If they have a cat with a loss of lean body mass, they might feel a little helpless with telling an owner what do I do? So we need to learn how to help intervene when there is muscle loss. Some of this we have some tools now.
Some of this might be interventions that we can discover in the future.
The tools for now would be - another thing that sometimes is not done well in a nutritional assessment is a good diet history. Is this cat on an adequate diet for its needs? Is it on a low protein diet when it should not be on a low protein diet? Is it being fed the other cat in the household's renal diet? It's easier for the owner when that cat doesn't need that diet and maybe needs more protein to keep it on? Is being fed a form of a diet that's comfortable for it? Some older cats may decide a pate rather than chunks of something are easier to assimilate.
So we need the type of diet, the nutrients in the diet, the form of the diet. Does it have a subtle chronic enteropathy? Some work David Williams has looked at, published, said that a lot of these older cats have a loss of ability to assimilate nutrients and they may not have diarrhea. So, yes, the stools are normal, but the cat is still not taking in all the nutrients that it wants. You can have a normal stool with quite, quite a bit of extra fat and moisture in it and it still won't appear, appear loose. So does the cat have B12 deficiency? Often? Very, very common in older cats. They're no longer absorbing vitamin B12 and then they won't absorb other nutrients. Well, when that's deficient. So first of all, sort of looking at the diet, is it the right form? Is it the right diet? Do we need to supplement with B12? Do we need to supplement with possibly even vitamin E? Although that's a little harder to do because we don't necessarily evaluate that one in practice.
Is the feeding management correct for this cat? Can they get to their food? I mentioned earlier, they might want an interactive way to doing that the cat's comfortable with. Are we treating osteoarthritis? Are we treating dental disease? There's often a feeling, oh, I can't do a dental prophylaxis on this cat because he's older and I don't want to anesthetize him. But we now know that dental disease is associated with heart disease, with renal disease, as well as a poor appetite. So, yes, these cats need careful anesthesia, of course, but they need their teeth taken care of so they can continue to eat adequately. And this is something that is. Sometimes owners are afraid of having their older cat have a dental prophylaxis, but it's what it can do for the quality of the cat is very important that I've mentioned activity already. So there are interventions that we can make. There are very practical, easy things that we can do. Raise feeders, raise watering bowls to let the cat get to it. So there are things that we can do to help manage these cats and make them more comfortable and maybe slow the progression of their sarcopenia and treating any comorbidities. They have to slow the progression of any disorders as well.
[00:17:02] Gómez-Mejías: If I understood it well, when we talk about frailty, we are talking about quality of life and we are talking about addressing underlying conditions that are affecting the, the overall, the overall health state and our mental well being as well. I'm so glad you highlighted the need of implementing good dentistry protocols. You know, like paying attention to those things, paying attention to arthritis. And thank you so much for highlighting as well, the difficulties to assessing muscle condition score. I personally was very grateful when you said that, you know, when you mentioned about the difficulties to validate the measurements because I don't feel particularly good at putting like a precise number on it. But knowing that I'm recording my impression on the form, knowing that that's useful in itself has been very, very rewarding. Thank you very much. I see your cat there. So everybody who is listening to this, she's got an amazing, very, very beautiful cat. So thank you so much for sharing your experience. And what were you going to say about your cat?
[00:18:06] Chandler: He is the cat that's on the picture on the, on the front of the article.
This one, right? Yeah.
[00:18:14] Gómez-Mejías: Brilliant, brilliant. It's a beautiful, beautiful cat.
So thank you so much for sharing your expertise, Marge, and for writing such a helpful article to our listeners. Thanks for tuning in and we'll be back next month.
[00:18:28] Conclusion: Thank you for listening to this episode of All Cats Considered. We hope you enjoyed this interview.
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