Yaiza Gomez Mejias: Welcome to another episode of Chattering with iCatCare. I'm Yaiza Gomez, Veterinary Community Coordinator, and today we have the pleasure of interviewing Marge Chandler, 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. 

Marge Chandler: Thank you for the opportunity to discuss this very, very important topic for cats. I think this is gonna hopefully change things the way that we practice. 

Yaiza Gomez Mejias: 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?

Marge 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 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 we 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 ageing cats, humans, mammals of all kinds. It's thought to be an overall concept, at least in mammals. So this is considered to be a common ageing change. Cachexia is the muscle loss associated with inflammatory mediators due to illness, sometimes injury, but really more with illnesses, chronic illnesses, heart disease, renal disease that go along with that. You know, I was thinking earlier about this, and does this include osteoarthritis as a disease? And I guess it 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 most older cats who have cachexia due to chronic disease would also have sarcopenia. So they certainly can be combined and I think that's probably a very common feature. In older humans that could be a common feature to have both of these. One of the differences between them is with cachexia, the muscle loss can be more profound and rapid. I think when we see this in an older cat who's gone downhill, so to speak, that we need to look for something more than an ageing change.

Yaiza Gomez Mejias: You mentioned frailty. What is frailty? 

Marge 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 a 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 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, yowls all night. We certainly recognise that 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, 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. I do wanna mention that frailty index because that came out as I was writing this paper and I found this really exciting because we had three for dogs and a bunch for humans, and this was the first one that we have for cats. There was recently published a pilot study on looking at developing a frailties 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 the meaning for this for owners. It's an assessment from owners and for vets, and this gives us a great tool to assess the functionality of looking at muscle loss in cats.

Yaiza Gomez Mejias: At what age roughly do we expect these changes to start occurring? 

Marge Chandler: 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 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 the 15-year-old cats, 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. It's a small percentage each year, but this would be maybe a 5 or 6-year-old cat might too have a little bit at that time. Now, can we assess this? Probably 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 roughly the 10 to 12-year-old cat. So this is probably when the loss becomes more profound due to sarcopenia alone. Now a cat of any age, of course, could have cachexia, could have an illness, a chronic illness that will cause the muscle loss potentially much earlier if they're younger when they get kidney disease or another debilitating disease. So certainly something we need to start considering more than just thinking about 'oh the thin old cat'.

Yaiza Gomez Mejias: Yeah, it's something that needs a very proactive approach, isn't it? My cat, I had to euthanise him when he was 17. He had experienced some muscle waste, 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, I guess they develop ways to counteract that relative weakness as well, and it may contribute to the barriers that we have to detect it. 

Marge Chandler: I certainly had an older cat who had a 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 us are affected by a degree of sarcopenia as we age. I've got a 70-year-old friend who runs marathons. There's a big difference in how it affects individuals and a big difference in our own mental and physical resilience too, and in determination to continue. So there's a lot of individual variation in that, which might be what you were seeing in your older cat is that he was able to overcome that in some way. 

Yaiza Gomez Mejias: Another term you mentioned in your article when you write about ageing is anabolic resistance. What does this consist of? 

Marge Chandler: Anabolic resistance is an interesting concept. It's not proven in cats, but it happens in other mammals, certainly humans and rodent studies, that with age due to changes in various hormones and cytokines and other metabolites, such as IGF1, insulin like growth factor one, the muscles are less responsive to assimilate and utilise amino acids so that it takes, for an older human, more protein to synthesise muscles than for a younger individual. Years ago, we used to always say older cat should have a decrease in their protein intake. We had an incorrect idea then that this would prevent renal disease, which it does not. Older individuals need an increase in protein or possibly an increase in some specific types of amino acids. 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. 

Yaiza Gomez Mejias: Now, are there any risk factors that would increase the likelihood of sarcopenia? Is it associated with anything else we may often find in older cats? 

Marge Chandler: Decrease in activity in humans is associated with loss of muscle mass and function. Ageing is the risk factor and that one's hard to prevent, but certainly poor diet, lack of exercise are recognised in humans as increasing frailty, as well as sarcopenia. The less you do, the less you'll be able to do. We need to encourage treatment for osteoarthritis, any other mobility problems that the cats have. Encourage owners to continue to play with their older cats, to keep them active with their activity, taking 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 being able to look around the house in ways they're comfortable for them. Cats are hard to exercise. We can't take them out unless they're lead 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. 

Yaiza Gomez Mejias: Knowing how relevant muscle condition score is, this podcast hopefully will encourage some vets to comment to their colleagues, and which are the most common barriers you think we find to evaluating and interpreting muscle condition scoring as part of the physical exam?

Marge Chandler: This has been a frustration for us on the muscle condition score when we've published the nutritional assessment, which of course 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 develop 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. It's validated, but not as well validated as the body condition score. So one, they feel a 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. Again, evaluating over the lumbar muscles is probably a good place to start in most cats.
Secondly. What do I do with this information? It's a little harder to know of an intervention for muscle loss for vets in practise right now. If they have an overweight cat, they know what needs to go on a 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 a nutritional assessment, the 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 households renal diet because that'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 pâté 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? David Williams has looked at and published, said that a lot of these older cats have a loss of ability to assimilate nutrients and they may not have diarrhoea. 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 a bit of extra fat and moisture in it, and it still won't appear loose. So does the cat have B12 deficiency? Often very common in older cats, they're no longer absorbing vitamin B12, and then they will absorb other nutrients. So first of all, looking at the diet. 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 wanna anaesthetise 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 anaesthesia, but they need their teeth taken care of so they can continue to eat adequately. The owners are afraid of having their older cat have a dental prophylaxis, but what it can do for the quality of the cat is very important. I've mentioned activity already, so there are interventions that we can make. There are very practical, easy things that we can do. Raised feeders, raised 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.

Yaiza Gomez Mejias: When we talk about frailty, we are talking about quality of life and we are talking about addressing underlying conditions that are affecting the overall health state and our mental wellbeing as well. I'm so glad you highlighted the need of implementing dentistry protocols, 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 mentioned it, difficulties to validate the measurement 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's useful in itself has been 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. 

Marge Chandler: He is the cat that's on the picture on the front of the article. This one, right here. 

Yaiza Gomez Mejias: Oh yeah. It's a beautiful, beautiful cat. 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.