Dr. Hille Fieten: Copper Toxicity

Copper Toxicosis Summary

Below is a summary of what you need to know about copper toxicosis, based on Dr. Fieten’s discussion in this episode. For more details, the full transcript is below.

• What is copper toxicosis?
  • Copper is necessary for life but too much is toxic.
  • The body carefully regulates copper levels – it uses multiple proteins (encoded in multiple genes) to do so.
  • There are both copper deficiency and copper toxicity (overload) disorders
  • In copper toxicosis (overload) in dogs, copper accumulates in the liver and causes chronic hepatitis (liver disease).
  • You may not see problems with your dog until later stages of the disorder – but it’s better to catch it earlier than this. Signs would be decreased appetite, vomiting, lethargy, jaundice.
• How is copper toxicosis diagnosed and treated?
  • To find the problem before the late stage described above, you can test liver values with a blood test. If this is positive, in order to definitively diagnose copper toxicosis you need a liver biopsy, as elevated liver values could be due to a variety of other problems. 
  • If the dog has hepatitis, it must be treated as it is very serious. Additionally the copper buildup must be reduced. This can be accomplished with medications such as D-penicillamine, and the dog’s diet may also need to be changed to a low copper diet.
• Who is at risk for copper toxicosis?
  • Dr Hille Fieten’s laboratory has identified two genetic variants for which there are tests
  • ATP7B (“bad”) – a variant of this gene increases the risk of copper toxicosis in Labrador Retrievers and Doberman Pinschers
  • ATP7A (“awesome”) – a variant of this gene decreases the risk, also in labs and dobes
  • Dogs with both the “bad” and the “awesome” variant are probably not at risk
  • Dogs with only the “awesome” variant are not at risk
  • Dogs with only the “bad” variant are at increased risk. They are at mildly increased risk with one copy of the variant, and greater risk with two copies.
• My dog is at increased risk. What should I do?
  • Select a diet low in copper and high in zinc.
  • You may choose to monitor liver enzyme values with periodic bloodwork. There is not a recommendation on the frequency with which you should check – at least annually, but potentially more often.
• My dog has the “bad” variant but is not a lab or a dobe. Are they at increased risk?
  • Fieten does not believe all breeds are affected by these variants but she does not know which are and which are not. They are working on discovering more, but for now, we don’t know.
• My dog has the “bad” variant. Should I breed them?
  • Ideally we should be reducing the “bad” variant (risk allele of ATP7B) from the populations at least of affected breeds.
  • As always, any breeding decision must be made in light of the full situation and what other traits the dog has that you wish to preserve.
  • A heterozygous dog may still be at increased risk, so producing a heterozygote is not necessarily protective as is the case in some disorders.
  • Pairing the ATP7B risk variant with the ATP7A protective variant is probably protective and this is a potential way forward if you have other traits you wish to preserve from this dog.
• I am worried that my dog might have copper toxicosis. What should I do?
  • You may wish to see an internal medicine specialist to work up and treat this case.

Resources

• Dr. Hille Fieten, Copper Toxicity (the Functional Breeding Podcast): https://functionalbreeding.podbean.com/e/dr-hille-fieten-copper-toxicity/ 
• Fieten, Hille, et al. “The Menkes and Wilson disease genes counteract in copper toxicosis in Labrador retrievers: a new canine model for copper-metabolism disorders.” Disease models & mechanisms 9.1 (2016): 25-38.
• Fieten Lab’s summary: https://www.uu.nl/en/background/hereditary-copper-accumulation-in-labrador-retrievers-be-alert

Podcast Transcript

Jessica Perry Hekman  

Hi, friends. Dr Hille Fieten is a veterinary researcher and clinician specializing in internal medicine. She’s also the coordinator of the Center for expertise in genetics and veterinary medicine at Utrecht University. I’ve received multiple requests to talk to her about her research into the genetics of copper toxicity in dogs. Some of her research has been used for new genetic tests, and the dog loving community is asking how to interpret these tests. So buckle up for a lot of information coming at you in this interview. Welcome to the podcast Hille, I’m so pleased to have you here. So to start out, why don’t you just tell us a little bit about your job. You’re at Utrecht University. What do you do there?

Dr Hille Fieten  

Yes, now I’m very happy that you invited me, and I love to talk about my favorite topic, copper toxicosis. So yeah, I’m very pleased that you invited me for this podcast, and also very honored. Yeah, I’m an internal medicine specialist and geneticist, and I work at Utrecht University, at the Faculty of Veterinary Medicine. There I have a clinical job, there I see mainly Gastroenterology and Hepatology patients at the poly clinic, and I lead the genetics expertise center. And there, we work to find solutions for hereditary diseases and harmful breed characteristics. And what we do there in research is that we try to identify genetic mutations that are responsible for hereditary diseases, but we also have a societal role in improving the animal welfare in breeding.

Jessica Perry Hekman  

Oh, wonderful. That sounds like such an interesting job and very important, right? There’s been a lot of interest in your work. I had multiple requests to have you on because your recent research on copper toxicosis has been very interesting to a lot of people. How did you get started? How did you get interested in, did you first want to be a veterinarian and practice? Did you first want to do research? How did you end up in this job? 

Dr Hille Fieten  

Yeah, that’s quite interesting. So now, after finishing a veterinary medicine school, I always wanted to become an internal medicine specialist, and I first did a rotating internship, and then I applied for residency, and then my professor at that time said, well, Hille, maybe you just start first doing a PhD, and then if you have completed the PhD, you can apply for a residency. And then there were different topics for PhD that I could choose from. And then I was very excited about the Labrador copper toxicosis project that was in our faculty, so I really wanted to do that. And so that’s how it started. And I got a PhD, then the PhD position, but then I realized that, well, my background in genetics, coming from a veterinary school, was not not good enough to really be able to identify genetic mutations in a complex genetic disorder. So during my PC, I did a master in genetic epidemiology, and now eventually we were able to solve the to identify the gene mutations, was during my PhD. And yeah, the PhD became a project in itself. So we did a lot of clinical studies, also with diet. So it took much longer than was anticipated, because I was really excited about this project. And then, after finishing the PhD, I went back to the clinics that I did the residency in Internal Medicine, and after passing the boards, I went back to clinics as a now clinical specialist, and also now as a leader of the expertise and the genetics team. But now copper toxicosis is still, yeah, a topic really close to my heart, so I’m happy that I have a few PhD students now who continue to work in that as well.

Jessica Perry Hekman  

I also did a PhD after veterinary school, but I never got back to clinics. I have nightmares sometimes that I would be asked to go back and practice and that I don’t remember anything, particularly internal medicine, which, for people who don’t know, internal medicine, is very complicated. There’s a lot to know. There’s a lot to know. So, I was assuming that your PhD was in genetics, but it sounds like it’s not, what was your what’s your PhD actually in?

Dr Hille Fieten  

Yeah, actually, my PhD was in copper toxicosis in Labrador Retrievers. So the PC was aimed at finding the genetic mutations of the copper toxicosis in the Labradors. But I also did a lot of treatment studies so that we try to identify what is the effect of diet, and can diet be used as a treatment, for example, and only later in the PhD we were able to identify the mutations. That was after we did all the diet studies. And currently I have a PhD student who is now revisiting all the studies that we did then with the diet and looking back at the mutations that we identified and see now how the dogs with the different mutations reacted on the diet in high tide. So that’s quite interesting that she’s, she’s doing that work right now.

Jessica Perry Hekman  

Oh, well, we definitely, I definitely will want to ask you about that. So let’s, but let’s get some background for people who don’t know. So can you tell us what copper toxicosis actually is?

Dr Hille Fieten  

Yes, yes. So yeah, copper is a very important element, so it’s essential to have that in food or drinking water, because it has a lot of important functions in the body. For example, cellular respiration is important for the skin. It’s important for the nervous system. It’s important for iron transport. So copper is really, really important element. However, copper can also be very toxic, so that’s why copper metabolism is very highly regulated in the body. So there are many proteins involved in keeping copper safe within the body, and all those proteins that are involved in copper metabolism, if something goes wrong, so if there’s a mutation that can cause different diseases. So it can cause, for example, copper deficiency disorders, but it can also cause copper overload disorders. And copper overload disorder is copper toxicosis. Now the liver is the main organ which is involved in copper metabolism, so what we see in copper toxicosis is that copper accumulates in the liver and causes inflammation eventually. So it can cause chronic hepatitis and going to cirrhosis in dogs. In humans, it gives other phenotypes, other diseases as well. So in humans, we see also accumulation in the nervous system, so that can cause neurological disorders, sometimes even depression when there’s copper toxicosis, not in dogs, the liver is mainly affected.

Jessica Perry Hekman  

So since it’s the liver, I gather it could be a fairly serious disorder if untreated, could it be fatal? 

Dr Hille Fieten  

Yeah, so if there’s chronic hepatitis and progressing to cirrhosis, then it’s possible that it’s fatal, yeah

Jessica Perry Hekman  

Yeah, for sure. 

Dr Hille Fieten  

But all animals with high copper will, by definition, develop chronic hepatitis or cirrhosis. So that is yeah, that is important to realize

Jessica Perry Hekman  

For sure, so okay, so then, what, what would make someone think that their dog might have copper toxicosis. What would cause them to go to a veterinarian and say, there’s something wrong with my dog and the veterinarian might then suspect copper toxicosis, like, how would it first present? 

Dr Hille Fieten  

Yeah, so that is quite, that is one of the most difficult parts from this disease, yeah, because the only basically get clinical signs in an advanced stage of the disease, because now the liver has a very large reserve capacity, so only if maybe two thirds of the liver is not functioning anymore, then you start to see typical clinical signs from chronic hepatitis. So that is not necessarily corporate associated hepatitis. It can also be other forms of hepatitis which are also present in Labradors or Dobermans, for example. So if you start to see really clinical signs related to liver disease then, then usually there’s already quite an advanced disease. So what you can see then is maybe decreased appetite, vomiting, icteric mucous membranes. And in further advanced disease of liver failure, you can get coagulation disorder, so a high tendency of bleeding, ascites, fluids in the abdomen. But that is mainly end stage liver disease, and that is also the frustrating thing, because when we see these patients on the polar clinic, then yeah, they usually they can be already in quite an advanced stage of the disease where treatment is less effective, so especially in the case of copper toxicosis, which has a chronic onset because copper needs to accumulate in the liver. And if it comes to a certain toxic level, then the liver is more prone to become inflamed and to develop hepatitis, and sometimes also other factors play a role. So if the liver is under stress, or the liver needs to produce a lot of things, that can also maybe be a trigger in the liver that is already loaded with copper to really develop chronic hepatitis and become clinically ill from the disease.

Jessica Perry Hekman  

So, in other words, someone might not realize that there’s anything wrong until the case is very far advanced and there’s very little that can be done. Is that true?

Dr Hille Fieten  

Yeah, that’s true. Now the other side is, what’s, what can be a first sign, but that’s not that it’s clinically noted by the owner. Is that the liver enzymes rise. So, sometimes a veterinarian takes blood for some other reason, or the dog needs anesthesia for some reason, and the veterinarian finds that the ALT is increased. Now that can be an indication that there’s something wrong with the liver. So also, sometimes those patients are referred, especially if they are from breeds that are predisposed to copper toxicosis or other forms of hepatitis, and then we take a liver biopsy, histological liver biopsy, and then we can diagnose or find that there’s copper, and then we can also start treating that and then prevent that chronic hepatitis will develop in that animal.

Jessica Perry Hekman  

So liver biopsy, obviously would be the preferred method of diagnosis, and that, for people who aren’t familiar, that’s relative, that’s fairly invasive. So what, could you explain to people, maybe, why a liver biopsy is necessary, why you can’t just do a blood test to see what’s going on? 

Dr Hille Fieten  

Yeah. So now in the blood is that you can test liver enzymes. ALT is the most stiff liver enzyme, so that if there’s any liver damage, copper related or non copper related, ALT may rise. So that is the first thing that goes up when something is wrong with the liver. But yeah, then the next step is, for example, to do an ultrasound of the abdomen to see, are there any other reasons why the ALT is high? Is there maybe anaplasia, or is there something wrong with the gallbladder, or are there other things in the body that can cause ALT to rise? Now, if that is not the case, now that you can do a sub step. So you could also do a fine needle aspiration biopsy from the liver, and that is just with this fine with a thin needle where you but you also used to take blood, take some cells from the liver, do the cytology, and you can also stain cytology for copper. And so that’s not always very sensitive, but if you already find positive copper on the cytology that is an indication that there’s something. But if you really want to make a diagnosis, so if there’s persistent high ALT, then a histological biopsy is necessary. And you can do that in several ways, from very invasive for example, by a laparotomy, by an abdominal operation to remove a piece of liver, or laparoscopically through a loop hole surgery, take a little bit of tissue. And we do often, very often, ultrasound guided with a true cut needle, so that is least invasive for the animal, and because copper toxicosis is throughout the liver present, so we can also make a good diagnosis by using that technique, which is less invasive than a goal search.

Jessica Perry Hekman  

Yeah. None of the things that your your regular general practice veterinarian could do, though, so that people should be prepared for this to be a more complicated diagnosis and complicated series of of tests and and so and so it’s, it’s, I think it’s important for people to understand that the copper builds up specifically in the litter liver, is what you’re saying, and that it’s not that there would be too much copper in the blood or the skin or anywhere that’s easier to get at, that the liver is where it goes. And so we really have to assess the liver. 

Dr Hille Fieten  

Yeah, that’s correct. You can measure copper in blood, but it’s not. It does not stand in relation to what you find in the liver. So during our studies, we have to try to, we tried to find biomarkers that are specific for copper toxicosis. So things that you could measure in blood or could measure urine, but we were not able to find something that is really useful in diagnostics to diagnose copper at a certain moment. So yeah, we need still liver biopsy to confirm a diagnosis.

Jessica Perry Hekman  

That would be great if you could find something, something else for sure. So good luck. So how is it, yeah, sorry, go ahead. 

Dr Hille Fieten  

Good, yeah, we’re working on that. So currently, also my PhD students is, is working on a paper on micro RNAs to see if they could maybe be copper specific. But, yeah, a lot of work needs to be done to really validate that and to test if it is really useful. 

Jessica Perry Hekman  

So the micro RNAs would be in the blood, hopefully. So you could just do a referral blood draw, nice, oh, that would be great 

Dr Hille Fieten  

But it needs a lot of work sure if it can be really used as a diagnostic.

Jessica Perry Hekman  

Yeah, well, it’s good to know, at least you have a lead. So that’s something, all right. So then if you have diagnosed a dog with copper toxicosis. Let’s let’s say, I mean, obviously, if the dog is in advanced, advanced stage of liver disease, you have to deal with the liver, and that’s a whole separate story. But if it’s earlier, then what kind of treatments are available? What do you do?

Dr Hille Fieten  

The treatment is, is two ways. So if there’s already a lot of inflammation, sometimes we also need anti-inflammatory medication. So for example, prednisolone to to calm the liver down and to to to stop the fibrosis formation, to stop cirrhosis formation, and, yeah. The most important part, especially for copper toxicosis, is that we have to try to remove the copper from the liver. So that we can do that with copper collators. So for example, D-penicillamine is a medication. If you give it to the dog, it captures the copper and it will, and you will remove the copper via the urine. So when you give the pill, an hour later they start peeing copper. So that is one way to remove the copper from the liver. Also you need to prevent copper uptake, so that you can also use a low copper diet and also a diet with high zinc. So that is try to create a negative copper balance so that the copper is gradually removed from the liver. So we know that the medication always works. So if you start giving D-penicillamine for a certain period of time, you will de-copper the liver. Diet can also be very effective, but not in all dogs. So what we now find out with this study that I told you about in retrospect is that, for example, the dogs that are highly genetically additive, have more mutations in the ATP7B, that they are less likely to improve with diet adaptation alone. But in some dogs, you can normalize the hepatic copper just by adjusting the diet to a low copper diet.

Jessica Perry Hekman  

 So at the point that you know that the dog has the problem, you might then choose to do genetic testing to guide your therapy choices. Is that correct?

Dr Hille Fieten  

Yeah, so that is important, yeah. But, but now you can also, now that we identified two genes that are involved in copper toxicosis, you can also test the dog for genetic risk on copper toxicosis, so that you can also take preventive measures. So if you have a dog that has mutations that are in ATP7B in the copper toxicosis gene, then you can already feed the dog a low copper diet for example, so that you can, you can try to prevent copper accumulation. However, in Labradors, we identified two mutations. So we identified also mutations in the copper transporter, ATP7A and ATP7A is in the gut, so if an animal has mutation there, it will block copper uptake. So it is not so that you can give all the Labradors a low copper diet, because if, if they do not, if they only have the ATP7A mutation that blocks a copper uptake in the gut, then you can have, in theory, a copper deficiency. So for diet advice, for for Labrador, for example, it would be good to have the DNA mutations from ATP7B and ATP7A, and depending on the DNA mutations that you can choose a diet which best fits for your dog. And that’s a bit maybe bit complicated, so maybe I have to explain it a little bit better. Yeah, it must be found in our studies. So during the genetic studies, we tried to identify mutations that were associated to copper level, so not necessarily to hepatitis, so the development of the disease, but really how high the copper was. Now, we found first mutation in ATP7B, which is the B of “bad”. So if you have a mutation in ATP7B, the liver is not able to excrete the copper from the liver tissue into the bile, so the liver, the copper will build up in the liver. However, to our surprise, we also found another variant, and that was, oh yeah, in ATP7B that is also the gene that is involved in Wilson disease in humans. So that is a copper toxicosis disease in humans. It’s the same gene. Humans have 300 different mutations, and in the dog, we found the one, and we’re looking at more currently. But to our surprise, we found another locus, and that harbored gene ATP7A, and now we call it “awesome”, because if you have ATP7A from all that A from “awesome” that blocks copper uptake, uptake in the intestine. So when you have that mutation, the dogs are prone to have a lower copper and this gene in humans is involved in menkes disease. And menkes disease in humans is a very severe disease where people have, or little babies have very copper deficiency, and they die at a young age. And unfortunately, some laboratories call it menkes disease in the Labrador Retrievers when they test for the ATP7A mutation. So I sometimes I get a lot of concerned owners, and they say, Oh, help Hille, my dog has menkes disease. It will die. Can you please help us? Or what should we do? And then I have to say, well, if you have the mutation, ATP7A is A from Awesome, so it’s good, so your dog will be protected against copper to a certain level.

Jessica Perry Hekman  

If the dog only has the A mutation, but not the B mutation, would it then have deficiency?

Dr Hille Fieten  

Not necessarily, but in such a dog, I would not, maybe advise to feed a very low copper diet, because it may have the risk of deficiency. So the mutation has not a huge effect. So you see that the dog may have  lower copper but not to have an event that it will defend you will develop deficiency, but the chance may be a little bit higher. So I would not recommend to put those animals on a very low copper diet, which you would advise, maybe for a dog that has ATP7B mutation, then I would say, well, choose a diet with a very low copper level and a high zinc level, because zinc also blocks the uptake of copper from the intestine. And zinc is sometimes also used as a treatment to prevent copper re accumulation after you’ve been chelating the dog with D-penicillamine and you have to stop that at a certain point, because if you give too long D-penicillamine, and you will also get copper deficiency. So after a short period of treatment, the copper of the livers got rid of all the copper, and then you can give zinc tablets in order to prevent copper re accumulation in these animals.

Jessica Perry Hekman  

All right, so a is not too scary on its own, not too concerning on its own, and with B, A is protective, but the B mutation on its own, without A is something that would be fairly concerning if, if you had a dog who had just the B mutation, not the A mutation. How, how predictive is that of the dog getting copper toxicosis? And does the allele count matter, whether it’s homozygous or heterozygous? Does that matter? 

Dr Hille Fieten  

Yeah, definitely. So if we’re talking about ATP7B mutation, what we found in our cohort is, if you have two copies of the ATP7B, 80% of the dogs that we had liver biopsies from had high copper and also the highest copper levels in the liver. So not only increased, but also to a high extent. So, but also, if you have one copy of the ATP7B mutation, we saw that there are already higher copper levels than if you don’t have that. On the other hand, it’s not if you have, if you do not have any mutations in ATP7B, it’s not that you cannot have copper toxicosis. So we also found dogs that did not have mutations and that we found in ATP7B, but still had an increased copper so it is very dependent on the diet that the dog has been receiving. So if the dog was exposed to copper in the diet or in drinking water. And probably there are more mutations. So that’s not only the ATP7B mutation that is involved in copper toxicosis, but that there are more mutations, and that we are also currently researching if there are other factors influencing just the copper levels besides this, this only mutation in ATP7B. So in humans, there are more than 300 mutations described in ATP7B that are not involved in copper toxicosis. And it may well be that it is also the case in dog so we’re currently studying that as well,

Jessica Perry Hekman  

Which also leads to the question of, I know that this work was originally done in Labrador Retrievers, and I believe you’ve identified these mutations in other breeds. And I’ve been getting a lot of questions from people now that embark is testing. I think maybe some other companies are testing for this particular mutation. People who don’t have breeds that are normally considered at risk are seeing that their dog has one or two copies of the mutation, and they don’t know whether it’s concerning. Do you expect this to be breed specific, or would it affect any dog?

Dr Hille Fieten  

Now it’s a very interesting question, and we are also currently studying this, because this is really important. So we looked, we also had a really large cohort of Doberman dogs from which we had liver biopsies, and we found that in the Dobermans, ATP7 A and B mutations were present, and also the ATP7A mutation had a very low allele frequency. But the ATP7B mutation is also very common in the Dobermans, and we also see in the Dobermans that it has the same effect as in the Labrador. So one or two copies from the ATP7B mutation, they have a higher copper level in the liver. So we saw that. But, but what we should do, because now, in indeed, on the embark, there’s a lot of dogs that have ATP7B mutation present. However, there is also a lot more breeds affected with copper toxicosis, than are described in literature. So if we look at our practice, what we see in dogs that have copper toxicosis, sometimes now the shepherds, the Cocker Spaniels, English Cocker Spaniels, the Westies, the dalmations. So there are many other breeds in which we see copper toxicosis in the liver. However. So currently, what we are currently doing, also in collaboration with a research group in Texas is identify a very large data set of liver biopsies and see whether the breeds that have copper toxicosis, that are also the breeds, that have a high frequency of the ATP7B mutation. And for example, one of the breeds where ATP7B is very often present is a French Bulldog. But I’ve never seen a French Bulldog with a copper toxicosis in my practice. I will not say that they are not there, but it’s not a breed that is typically described as a dog, as a breed with copper toxicosis. So to answer your questions, it is, it may be possible that these mutations that we identified in ATP7B have the same effect in other breeds. For example, in the Doberman, we already found that, but not necessarily that, that it has the same effect in all breeds. So basically, we would need to validate the use of this test in other breeds. And that’s quite complicated, because what you would need is then from all these dogs from that breed, with and without the ATP7B mutation, have liver biopsy and see, do they have copper toxicosis? So that is quite an excessive undertaking. So, yeah, if so, if your dog is tested positive for ATP7B mutation, for example, and and it is not known yet, often, the breed is also at risk when you have this mutation and you are concerned, then that the best way, I think, to monitor your dog and to prevent things from getting worse is, for example, do regularly ALT measurements, and if the ALT increases? Now maybe that is then a moment to take a biopsy to be sure if there is copper toxicosis, yes or no. So that could be an in between, a solution, if, if you find that your dog has this such a mutation, and it is not currently known whether that mutation in your breed also causes copper toxicosis, as it is for the Labradors and the Dobermans.

Jessica Perry Hekman  

So how sensitive do you.. You, by the way, you guessed my next question perfectly, which was, what should people do if they’re worried, and so testing liver values sounds very easy and straightforward. How sensitive do you expect ALT values to be? So by the time that the ALT is going up, would you expect there to be significant damage to the liver? Or do you think that would happen fairly early on?

Dr Hille Fieten  

Now, that’s a really good question. So one of the studies we did is we looked at the ALT failures in the dogs that had already extremely high copper failures in the liver, and to our, to our surprise, or, yeah, it was maybe unexpected, because sometimes we found dogs with 3000 milligram per kilogram copper in their liver, really high values, with the normal ALT. So the ALT is not nes, if the normal ALT is not necessarily related to a normal copper level. So if you have a normal ALT, you cannot say, Oh, this dog does not have copper toxicosis. However, when the hepatocytes, so the liver cells start to die, the ALT will rise. So that is, not to make it more complicated, there’s also mutation now in the ALT gene, GPT gene, found. So that’s right, right? So the animals with that mutation have a lower ALT failure in general. However, it is then important to look at the individual dog. So if your dog always has an ALT of 20, and then it’s all of a sudden, he has an ALT of 60, although it’s still in the reference range, it is a rise. So that can be an indication of things going on. So if hepatocytes will die, so if liver damage starts, then the ALT will rise. But it’s not necessarily that if the if, if the ALT is normal, that there’s no copper, and so that is, that is the other way around, right? Yeah. Then the question is, How often should I test my dog for the ALT? So, that’s also a difficult question to answer, because you cannot predict when damage will start. So maybe yeah, at least once a year, I think so if you do, but yeah, you can also do it more often, but yeah, because, but it’s not so that if the ALT rises, that then the next day your dog has liver cirrhosis and will die. Usually, the pro process is slow, somewhat slower, however, not always. So I also had dogs that were clinically normal, and they were, in three months, they were dead, for example. So it can be very quick, but usually it goes slower, yeah.

Jessica Perry Hekman  

Yeah that was, that was sort of another question I was wondering. Let me think how to phrase this. So is, would it be possible that you would test the ALT and by the time the ALT has started to rise, there’s already so much damage to the liver that that the dog would be past saving basically, is that? 

Dr Hille Fieten  

Not necessarily, and, yeah, what is also important to take in mind is if there’s, for example, family history. So if you know that one of the litter mates, or if the parents or the offspring died of copper toxicosis, for example, then I would not wait for the ALT to rise. So then I would just do a liver biopsy from those litter mates, because then you have them in an early phase, and then you can really treat them, and then you can really prevent liver damage. So it depends also on the family history. So if you already know that, for example, also littermates have this, that you that, you be more thorough in the diagnostics and maybe early in disease, more early in the disease process, choose for a liver biopsy.

Jessica Perry Hekman  

Would you proactively be feeding a low copper diet in a dog with the mutation, or are there side effects to feeding a low copper diet? Is there a reason you would not want to do it if the dog was not going to have the problem?

Dr Hille Fieten  

That depends on how low is low. So I think that you could do it. I don’t think it harms a lot, especially if it doesn’t have ATP7A mutation. So if, but then I would maybe choose a diet that is relatively low in copper, but not completely no copper, so maybe five milligram per kilogram dry weight, something like that in the low range. I don’t think that will harm, I don’t think they will develop copper deficiency. So I think that that could be, could be done.

Jessica Perry Hekman  

I guess then the other question is, if you are feeding the, I’m trying to predict all the questions people will have, if you were to choose to feed the low copper diet, and then the concern is, maybe the dog could develop copper deficiency. How would you monitor for copper deficiency?

Dr Hille Fieten  

Yeah, that is, the first signs are very not so obvious. So sometimes, if it is really severe, they can develop anemia, for example, or they can develop discoloration of the hair, or brittle hair or skin issues, but that is with severe copper deficiency. So the liver is, if the body is really good at keeping copper. So I don’t think that a copper efficiency will develop very quick, very quickly, and also not just when you give a normal food or food with a little copper, and also if the animal does not have the ATP7A mutation, as for the I think that the risk for copper deficiency is quite relatively low. And only cases that we have, and that are described in literature is, for example, that dogs were treated with D-penicillamine very long, and that it didn’t stop, or that they continue to give copper chelators, and then in the end, the animals develop copper deficiency. But you have to do quite a lot of work to make that happen.

Jessica Perry Hekman  

Yeah, I imagine the body is very good at hanging on to copper in general

Dr Hille Fieten  

Yes, yeah. So that’s also what we see. So if we take dogs off the copper chelation, sometimes you see a very steep rise in copper in the liver again, because the body is then depleted of copper. And they try to, try to, yeah, keep the copper that is taken up afterwards then as well. Yeah.

Jessica Perry Hekman  

Right yeah. So I guess I’ve been having questions from people. I particularly saw a mixed breed litter recently where several of the dogs tested positive, and now I don’t remember whether it was the A mutation or the B mutation. It may even have been the A mutation, which then I wouldn’t be concerned about at all. And so people were asking, you know, should I get one of these puppies? Let’s assume it was the B mutation. So, so if it were the A mutation, then we would say there’s no concern. Go ahead and get one of the puppies and even breed the, you know, if the dog grows up, you could even breed a dog with the A mutation, because it’s really not concerning. So then, I guess the question is, how concerned, you know? I think what I’m hearing from you is, if I were considering buying a puppy who had a just, certainly just one allele of the B mutation I would, I would probably, particularly if it were not a Labrador and not a Doberman, and there were no family history, it seems like it would not be that concerning. Does that sound correct to you?

Dr Hille Fieten  

Yeah, I think that a lot is that we don’t know yet. So because we did, we studied the Labrador and the Doberman, and we know that. So it’s difficult to answer that question, because we do not exactly know what this mutation does in mixed breed dogs or in other breed dogs. But it’s not, it’s not that I think, oh, all those dogs will develop chronic hepatitis and they will die. So it is important to consider that the mutations only influence copper levels as they do not influence development of hepatitis by itself, the thing you will, but it’s related. But it’s good to realize, to realize that, and also because in Labradors and Dobermans also other disease mechanisms for the development of hepatitis exists, especially in the Dobermans, they have also really a form of autoimmune hepatitis. And in the lesser extent, we also see that in the Labradors, we see a female predisposition in both in Labrador, but also in the Doberman. So that can be breed specific, and it can be that the dogs already maybe prone to chronic hepatitis, and that every dog also has that copper that that maybe triggers more the development of clinical disease. So a high copper also does not necessarily always mean clinical disease when it comes to a certain degree, yes, so if it is higher than 2000 or even higher, then then definitely they will develop hepatocyte damage, and that triggers chronic hepatitis. But it can also be that then dogs can tolerate quite a high level of copper in the liver relatively without developing hepatitis. So it’s important to split those things, that a high copper in the liver is not necessarily the same as chronic hepatitis, cirrhosis and death. So yeah, if that is the case, now I would maybe say, well, try, do not give a diet with very high copper. But that is maybe in general, also the advice  for dogs. So I don’t think it’s necessary to have excessive amounts of copper in dog food. I think also that the international scientific community, who’s working on hepatology. Also did a cry out to the food industry “stop doing ridiculously high copper levels in the food”. And I think also they listened to it so that mainly the copper levels in dog foods have been going down in the last years. And yeah, that. And if you are concerned for some reason then measure the ALT, then maybe yearly, when you go to the vet for the vaccination. And so that’s if there’s something going wrong, that you’re early and that you can start preventing serious, serious disease.

Jessica Perry Hekman  

And that reminds me of a question that we had from a Patreon member, Anna, who asked exactly about the high level of copper and food and treats. And so she was asking if we should be considering monitoring copper intake for all dogs. She actually asked if we should consider occasional chelation therapy for all dogs, given how much copper is in food out there. And so. You’ve somewhat answered how it does seem to make sense to look for a moderate or a reasonable level. How would you go about let’s first, let’s ask. How would you go about finding a food? What’s a reasonable level of copper to have in food? 

Dr Hille Fieten  

I think less than 15 milligram per kilogram dry weight. So the diets that we used in our copper studies to remove copper from the liver, they were all lower than five, five milligram per kilogram or lower, based on dry weight. So, so those diets are considered very low copper, lower than five, but maybe 10 or 15 is, I think a reasonable amount. I don’t see any reason to go higher with copper in diets.

Jessica Perry Hekman  

Is that how it’s reported? Is that how it’s reported on the food bag? Do you know? You probably, I don’t even know if you would know how it’s reported on the food bag in the United States.

Dr Hille Fieten  

Usually it’s reported in milligram per kilogram dry weights if you’re talking about kibble, because wet food is a little bit different again, so yeah, the best is to calculate it based on the metabolizable energy that is in the food. But that is more complicated. But if you have a question, you can always ask a food specialist or the company to give you information, and further, it’s also important to see what compound copper is in food. So copper oxide is not biological, biologically available, and now usually there’s copper sulfide in the diet, ah copper sulfate, sorry, That is and that is biologically available. And yeah, what also the researchers and the veterinarians saw that in about the 90s, the food companies started to change the copper oxide, which is not biologically available to copper sulfate in the diet. And by that time, they also saw in the liver biopsies that the amount of copper in the liver biopsies, especially from genetically susceptible dogs, increased. So that was, yeah, also a trigger to see, okay, well, if the compound in which the form in which copper is in the diet is important. Now the other thing is, is the zinc level in the diet. So with zinc, it’s the same. So zinc oxide is not biologically available, so you would want to maybe choose a diet with relatively high zinc levels, and then also zinc that is in available, bio available form. So zinc methionine or zinc acetate or zinc gluconate, but not zinc oxide. So so that is the diet trials that we did, or with the diet with low copper and then relatively high zinc levels in t the food. But you can also ask, ask the food company if it is not on the back or what kind, what type of zinc or copper is in the diet.

Jessica Perry Hekman  

That is very helpful. Thank you. And I just remembered there was another question I meant to ask previously, which was, if you have a dog who was diagnosed with liver disease subsequent to high copper levels, and then you, you know, perhaps did chelation therapy. Had the dog on a lower copper food. How do you monitor the dog going forward? Does one just monitor ALT levels for the rest of the dog’s life? Would one do liver biopsies periodically? 

Dr Hille Fieten  

Yeah, and because in our studies, we gathered a lot of information. So during our studies with the Labrador Retrievers, we took every five every six months, liver biopsies from those dogs, so that we got a lot of information on that. So we now can predict how long you should treat a dog with chelation therapy based on the starting copper levels. So for example, if your dog has at the beginning a copper level of 1000s you should treat for a year. If it is higher, you should treat for one and a half year, for example. So you can then and then, what we did after chelation therapy, after we stopped that, we took a liver biopsy to check if the copper was gone because, but because we now already have all the data and we can predict how long we should treat, then we would say, okay, a year or six months after stopping chelation therapy, we take a biopsy again. And how quickly you do that after stopping chelation therapy depends on how much mutations the dog has. So if the dog has is double mutant for the ATP7B mutation, I would advise, okay, do six months after stopping the chelation therapy, a controlled liver biopsy if he does not have the ATP7B mutation, maybe do it after one year, so that you also have an idea how quickly the dog re accumulates copper. And now, what you could do after chelation therapy then start zinc, zinc tablets. So zinc cannot be combined with d-penicillamine in the treatments, but you can give zinc to prevent copper re accumulation. Now what we found was that many of the dogs that were treated in our studies never needed chelation therapy again. So after they were d-coppered and then put on a low copper diet, and that went very well for years. And now, in hindsight, we look at those dogs that were re accumulating faster. Those were the dogs with mutations, with more mutations. So the paper is going to be submitted in the coming weeks. So it’s, I think it’s really interesting to see that we looked in hindsight again at the data that we gathered then and that we learned a lot from those studies. So yeah, so ALT monitoring is important. However, when the ALT rises, you do not necessarily know if it is the copper or is it another form of hepatitis, especially in the Labradors in the Dobermans. So yeah, you usually need the liver for biopsies for control. However, due to all the results that we got from the studies, we can now minimize the frequency of biopsies, because we got all this data, so we know approximately after which period you need to do a recheck biopsy.

Jessica Perry Hekman  

That’s great. You, your lab sounds so thorough. So I was curious how widely, how widely disseminated that information is. And you mentioned one paper that’s about to be published. So if someone has a dog who’s going through this process right now, would they expect an internal medicine specialist to know the process, or would they need to, perhaps, specify to them that there’s some interesting papers out from Hille Fieten’s lab, and you should be, you should be taking a look at those as we make the decisions like, how are there recommendations that that most internists would know at this point? 

Dr Hille Fieten  

No, I think that internists working in hepatology. So there we have the Society of comparative hepatology. So a lot of people working in general medicine and are interested in liver disease. Yeah, I think they know. And in the USS use studies from Tariq law, who do now also the studies on cyclosporine and treatments. But yeah, I think you pointed it to the right direction that we should, could have done a better job in disseminating all the knowledge. So I’m really happy that you give me now the opportunity to talk, so that we get everybody conditioned to this.

Dr Hille Fieten  

And yeah, so we need to publish more and be more that information is widely available.

Jessica Perry Hekman  

It’s, I mean, it’s, once you do the research, then there’s that whole other step right of getting it out there into practice. And what I’m hearing from you is that a lot of the different things that you’ve suggested are not just something that I would even go to just so obviously, primary care doctors are not. Veterinarians are not going to be able to do any of this, but not even all. Internal medicine specialists are the right person to go to. It might be that you specifically would want to go to an internal medicine so for those who don’t understand, right? So you’re veterinarian, then you can do an additional residency, like Dr Fiton did, to become an internal medicine specialist. But then once you’re an internal medicine specialist, you can also decide to specialize in different systems. So when I was in veterinary school, we had, I could tell you which of my internal medicine teachers specialized in the kidneys, which specialized in the liver, which specialized in the GI like I knew who they were. So finding someone who’s a liver specialist, but that could be really hard for some people, right? I mean, they may not have a, some people even find it difficult to find an internal medicine specialist locally. And I think finding, they may not even know how to find someone who specializes in the liver. And I don’t know if that’s something you can, you can speak to. It may just be that you do the best you can, or you ask around on the internet but that’s hard.

Dr Hille Fieten  

Yeah, I understand now, yeah, a veterinarian can always, they can, of course, do the ALT measurements, they can do that. But yeah, I think we needed to do a little better job to to get all the information out there that is available, that we can put it on the website, or make guidelines for for lay people, that they can find it, and especially now all the DNA tests are out, so that that people are worried, or, yeah, that that’s that is good, that you say that, that we should do that.

Jessica Perry Hekman  

Yeah, we can, we can think about, we’ve, we’ve done this for the Functional Dog Collaborative, the group that this podcast is a part of has done that before. Sometimes I’ll do a podcast episode with someone and realize that there’s a need to summarize some of it. And that’s what I’m hearing, yeah, hear from you is that we may need to do a summary to help people with some of this. So that so, so finding that specialist, and then the other thing that I heard that could be challenging for people is doing the liver biopsy, because you listed a bunch of different options, and the level of invasiveness is pretty different. So you, so one possibility is that the dog actually has surgery. The person you know, the veterinarian cuts the dog open, goes down to the liver and takes part of the liver out. And obviously, abdominal surgery is one of the more invasive things that can be done, short of rabies testing. That’s a funny veterinarian joke. So so, but then you also mentioned that there you could do, for instance, ultrasound guided true cut with a very fine needle. But so then again, people would have to know to advocate for their dog, right? They’d have to know that they would need to look around for different options, yeah,

Dr Hille Fieten  

No, so a true cut is quite is little bit more invasive, so that you need to coagulation testing and but so the true cut liver biopsy ultrasound guided is something different than fine needle ultrasound guided biopsy.

Jessica Perry Hekman  

Yes, sorry I misspoke. You were saying that. Yes. I said, Fine, but true cute, yes. So right. So the options would be the surgery, which I think would probably be the easiest to find, but the most invasive. So, Fine Needle Aspirate, you were saying that might not be the best diagnostic, that would be the least invasive, but maybe not provide the best diagnostic data?

Dr Hille Fieten  

From a fine needle biopsy, you have to do specific staining for copper, that’s also for the histology. So that’s also something that goes wrong often. So you really have to ask the pathologist that they do a copper staining, otherwise they will not find copper in histological biopsies of the liver. So we use a lot of rubeanic acid staining that stains the copper black. But in US, rhodanine in staining, for example, is used and that colors the copper red. So you cannot only do that on histological biopsy, but also on cytology. So that you collect some cells, and if that is positive for copper, then you have an indication that there’s quite a lot of copper in the liver. However, if it’s negative, it can still be that there’s some copper in the liver that’s missed. So it depends also on how much fine needle you do from the liver.

Jessica Perry Hekman  

You wouldn’t have the actual number value that you get from a biopsy, which sounds like it’s useful in determining treatment.

Dr Hille Fieten  

Yeah, that’s really correct. However, in cytologists, we there is some papers out that they score cytology also a 01234, how much copper positive cells are in cytology. But it’s not, it’s really samey, samey, samey, quantitative. While in those histology, you can see how much copper, you can see how much inflammation, how much fibrosis. So the histological biopsy is much better. What you could consider is, for example, if you do a sterilization of the dog. How you say neutralization

Jessica Perry Hekman  

Yeah if you’re, if you’re neutering the dog, spaying or neutering.

Dr Hille Fieten  

So at that time, you can, for the bitches, you can collect a piece of liver. Also, laparoscopic sterilization/neutering is often done. So then it’s not so much effort to also take then, but only those dogs are usually younger, so they usually biopsy they’re maybe at two years of age. So, and copper toxic goes when they got ill of it, yeah, usually after three years of age. And much more often, 5, 6, 7, 8 years of age, so when they really become ill. But then, yeah, if they already have high copper at two years of age, when spaying or at a very young age, yeah, then you know, okay, we have to do something. So yeah, if you are considering spaying or neutering the dog, a female dog, then it’s maybe not a very big effort for the vet to also take a little piece of liver. 

Jessica Perry Hekman  

Good point. So as you’ve measured the mutation, the genetic mutation, in different dogs, have you been able to assess how many Labradors and how many Dobermans have the mutation, what the allele frequency is in those breeds?

Dr Hille Fieten  

Yeah, so for the Labradors, I looked it up for the Labradors just before this podcast. So for Labrador, the Dutch Labradors, we found in our study population that it was around 30% allele frequency of ATP7B mutation. But that may be a little bit of bias, frequency because in the way we collected a lot of dogs in our data set, where family members of affected dogs. So what we found from the embark data from ATP7B mutation was in the Labradors, 13% in the USA. And what we found, for the ATP7A mutation, that it was approximately 20 to 30% in the Netherlands and in the USA population. For was, let’s see around 30, ATP7B, and for ATP7A, 0.3, but I need to check that, so maybe not good that I tell that number now for the for the embark data, but we also going to publish that. So we looked it up for all the different dog breeds. We got all the data from embark, so that will be also in the we are going to do the paper and all the other breeds, and we will also record the earlier frequencies from the different labs that test that.

Jessica Perry Hekman  

All right, we’ll definitely watch for that. It sounds like, I believe you would recommend trying to reduce the frequency of the ATP7B mutation. But of course, the question is, how many you know if, if a large proportion of the dogs have it, then it’s harder to reduce it, but if we assume that the if we assume that the frequency was fairly low, then would you recommend trying to breed away from it? 

Dr Hille Fieten  

Yeah, from the Labradors and the Dobermands, yes.

Jessica Perry Hekman  

Yeah, I would think so. All right, so then my, my last question is, what’s the future of your research, and you’ve already talked about a lot of interesting work that’s going on. Is there anything else going on in your laboratory that I would that I should have asked about but didn’t know about?

Dr Hille Fieten  

Yeah, we also, we also studied Doberman hepatitis. So we were supported by things that we didn’t mention already is that we support, we were supported by the Morris Animal Foundation, and to study specifically Doberman hepatitis, because that has a little bit of different etiology than in the Labradors. So, yeah, really the autoimmune component is important. So yeah, we try to identify genes that are involved in the development of hepatitis, not only copper associated hepatitis, but chronic hepatitis in general, in the Dobermans and also in the Labradors. So yeah, this is also something I found it a really exciting project, and with all the support of the Morris Animal Foundation, we’re really grateful for that, that we can also pursue this work for the other breeds.

Jessica Perry Hekman  

They do a lot of really good work, and it’s a lot of excellent support for researchers who really need it. It can be really hard to get the money to do this kind of research, as I know from my own life. So good for them. 

Dr Hille Fieten  

Yeah, we do a lot of other genetic studies. So this is only related to copper and liver. But we do genetic if you’re interested, we do genetic research. Yeah, in liver shunts, overbite in the Huskies, stomach carcinoma in the Belgian Shepherds, polymyositis in Koiker dogs which is a dutch breed, myelopathy. So yeah, we have many, many different genetic projects, epilepsy, chiari malformation, syringomyelia. Yeah, yeah. There’s a lot to work on. 

Jessica Perry Hekman  

Oh wow, So is there, are there any other studies? Have there been any other mutations that you’ve identified that would be worth discussing? Are you still, are those still newer projects?

Dr Hille Fieten  

Yeah, several, but not necessarily in the Labradors and in the Dobermans, but for example, in the stomach carcinoma we worked together with a group at Cornell University, and in collaboration, we were able to identify risk factors for gastric carcinoma, so that we also try to develop a test for that. Cerebellar ataxia in flat goals, recently polymyositis in the Kooiker dog. So yeah, many, many exciting things that come and yeah, also more complex genetic diseases. So the monogenetic diseases that those are interesting, and also the low hanging fruit for the geneticists, but for sure, yeah, we try more and more to also help in with the more complex genetic diseases in which we can do risk factors or polygenic risk scores to see. Yeah, what we also developed is what I also always call the Tinder for dogs. So that is really a population management system “fit to breed” is called, that is what we use now for Kooiker dogs. It’s really interesting. So if you have another podcasts, I would be really happy to talk about what do we do with that.

Jessica Perry Hekman  

So that sounds very relevant to us. So just a quick overview. So it’s so what that tells you, this gives advice about whether the dog is appropriate to breed? Is that what it is? 

Dr Hille Fieten  

Yeah, but also the combination. So it’s like a population management tool, which combines all the data that is there. So it combines clinical data, screening data, genetic data, snip data, everything, and now we include the kinship between the dogs. We include the risks for certain diseases. So yeah, actually, everything that is evaluated that’s available, we include in that, and it’s very successful now for the Kooiker dog, and we’re also now going to develop that for the guide dogs, for the assistant dogs population in the Netherlands, where we collaborated.

Jessica Perry Hekman  

I’m taking a note right now that we should, that we should find another time to talk about that. Yeah,

Dr Hille Fieten  

See, that’s very mission. So it all started with copper toxicos in the Labradors. That was my PhD. That’s where it all started. But now, when working as a veterinarian, you’re so often, you have to deal with all these hereditary diseases and suffering of animals due to harmful breed characteristics. That really the mission of our group, is to really try to help in solutions, that we really try to to prevent these diseases, and instead of treating them, or wasting our time in treating them, because often very difficult to treat, they cause a lot of harm to the animals, and it’s, they’re very heartbreaking for the owners. So now we dedicated our lives to improve that and to really start at the, in the prevention of these things.

Jessica Perry Hekman  

That’s so important, and I completely agree that prevention is so much better than treatment, but it’s so hard to have people understand how important it is, because the, the word I use is that the treatment is sexier, which is sort of a silly joke, right? But, um, it’s just, it’s, it seems so important to treat the animal in front of you, and it is, we should not stop doing that, of course we should keep doing that. But so much better for everybody if we can prevent the diseases before they start. So that’s very important work. I’m really glad you’re doing it. 

Dr Hille Fieten  

Thank you. Yeah. Now we’re doing our best. And thank you for inviting me and to talk about copper.

Jessica Perry Hekman  

Yes, yeah, yeah. Thank you so much for making the time. 

Dr Hille Fieten  

You’re welcome. 

Jessica Perry Hekman  

Yeah, we will talk again soon. For sure.

Dr Hille Fieten  

Great. Thank you. 

Jessica Perry Hekman  

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Jessica Perry Hekman  

Thanks so much for listening. The functional breeding podcast is a product of the functional dog collaboration, and was produced by Attila Marta. Come join us at the functional breeding Facebook group to talk about this episode or about responsible breeding practices in general. To learn more about the FDC, check out the functional breeding.org website. Enjoy your dogs.