Mitral Valve Disease Research Update
Spring 2012

Mitral valve disease (MVD) is the most common heart disease of the dog and it is probable that ALL dogs (whether pedigree or not) eventually get the disease if they live long enough. There is now a worldwide activity amongst veterinary clinical researchers trying to better understand this disease with the eventual aim of understanding how to prevent and cure this disease.

At the Royal (Dick) School of Veterinary Studies in Edinburgh we have been investigating MVD for 10 years and have made several important discoveries that give us a clearer understanding of what is happening; but there is still a long way to go. The Cavalier King Charles Spaniel Club have been valued supporters of our research over that period, and without the Club’s help we would not be as far forward as we are now.

There are several approaches to researching MVD being undertaken by groups around the world, and different lines of investigation being followed. At Edinburgh we are investigating MVD using 4 strategies and each effort is supported in part by the CKCS Club.
  1. The genetics of MVD in the CKCS; we have recently published a report supporting the long held view that if inherited in some CKCSs, it is a polygenic (involves many genes) rather than monogenic (one gene) trait. This study is being followed up with a much bigger study which will look at CKCSs that have MVD and are clinically affected, older CKCS with murmurs that are never clinically affected and older CKCSs that never develop murmurs. It is the latter group that are the most interesting, in that, while the breed is more adversely affected by this disease than other breeds, it shows that not all CKCSs have this disease. This provides a more powerful method to see if we can find culprit genes for those that are affected.

  2. Pathology of MVD specific to the CKCS; most work to date has looked at a mixed group of dogs with MVD. This in part reflects the availability of material. With the help of CKCS Club members we have been able to source valves from many more CKCSs than previous (this also helps the pancreas/liver and syringomyelia studies). The question we want to answer is the pathology of the disease different from that seen in other breeds of dogs? We know that CKCSs tend to develop the disease earlier than other breeds (pedigree and mixed) and wondered might it be a different disease? This is important to know as it would determine if information gleaned from all dogs was relevant or not to the CKCS. The data from this study clearly shows that CKCS disease is the same as that for all other breeds of dogs and we plan to present and publish this data as soon as possible. This finding suggests that the early onset of disease in the CKCS, and not the disease itself, is the feature specific to the breed.

    Cells in the mitral valve of a Cavalier King Charles Spaniel
    Cells in the mitral valve of a Cavalier King Charles Spaniel

  3. Novel genes in MVD; some work has been done previously to look at what genes and proteins are active in the valves themselves (not the same as the genetics of inheritance). To date, however this type of work has been patchy and very expensive to carry out. The opportunity now exists to look at this more closely with greater accuracy and for it to be affordable. The CKCS Club is part supporting a PhD student, Chi-Chien Liu, to look at a range of genes we suspect might be involved in MVD. The hoped aim is that this will give a better idea as to potential drug targets that could; be used to control or even reverse valve pathology. Chi-Chien (also known as Fox) is the recipient of a prestigious Charles Darwin Scholarship, and it was the support of the CKCS Club and the importance of MVD research at Edinburgh that helped him win that scholarship.

  4. Cell culture systems and tissue engineering: the use of real tissue from real cases is the ideal way to pursue research but the reality is it can be hard to get enough material. The sample collection scheme for CKCS is a wonderful development, and is probably unique in the world, and has allowed studies that would otherwise not be possible. Another strategy we are actively exploring is growing valve cells in the laboratory and taking that one step forward and growing complete valves. This is known as tissue engineering and while in the popular imagination this might suggest we can produce replacement valves for affected dogs, this is not likely to happen. What it does allow us to do is to examine ideas on why MVD happens in a controlled laboratory environment, and with a potentially endless supply of tissue. From that we can then try and extrapolate to the real patient, asking questions we would never be able to ask in the live animal. With these artificial valves we are now able to examine what happens when heart valves are damaged and how valve respond to damage and how might they repair.
Tissue engineered (artificial) mitral valve
Tissue engineered (artificial) mitral valve

Cultured heart valve cells
Cultured heart valve cells

So there is a lot of work on-going at Edinburgh and much of it being supported by the CKCS Club or only having come about because of previous support by the Club. As and when we publish our work and present it nationally and world-wide we always acknowledge the contribution of the CKCS Club. This support is a clear example of how cavalier King Charles spaniel owners and breeders in the UK take seriously the health and welfare of their pets, and their desire to cure this disease.

Professor Brendan Corcoran
Professor of Veterinary Cardiopulmonary Medicine
Royal (Dick) School of Veterinary Studies
Spring 2012
 
Back to top
 
Return to Heart Main Page
 
 
This document maintained by the webmaster@thecavalierclub.co.uk.
Material Copyright © 2012 The Cavalier King Charles Spaniel Club