In a study conducted at the University of Copenhagen, several researchers analyzed the tissue samples of dogs whose owners donated their bodies for research purposes.
Myxomatous Mitral Valve Disease is a heart disease that mostly affects Cavalier King Charles Spaniels but does occur in other small breeds. The disease also oftentimes occurs relatively early in life.
CoQ10 is involved in energy production and acts also acts as a potent antioxidant. It is primarily synthesized within the body but can also be supplied through supplements and diet.
Depleted Myocardial Coenzyme Q10 in Cavalier King Charles Spaniels with Congestive Heart Failure Due to Myxomatous Mitral Valve Diseas
The study involved 40 dogs; which were grouped based on the classification system developed by the ACVIM. 10 dogs were classified as control, 11 B1, 5 B2, 14 C. All of the dogs in the disease groups were King Cavalier Charles Spaniels. While the healthy dogs were several different breeds.
“Stage B1 describes asymptomatic dogs that have no radiographic or echocardiographic evidence of cardiac remodeling in response to their MMVD, as well as those in which remodeling changes are present, but not severe enough to meet current clinical trial criteria that have been used to determine that initiating treatment is warranted (see specific criteria below).
Stage B2 refers to asymptomatic dogs that have more advanced mitral valve regurgitation that is hemodynamically severe and long standing enough to have caused radiographic and echocardiographic findings of left atrial and ventricular enlargement that meet clinical trial criteria used to identify dogs that clearly should benefit from initiating pharmacologic treatment to delay the onset of heart failure (specific criteria detailed below).
Stage C denotes dogs with either current or past clinical signs of heart failure caused by MMVD. Because of important treatment differences between dogs with acute heart failure requiring hospital care and those in which heart failure can be treated on an outpatient basis, these issues have been addressed separately by the panel. It is important to note that some dogs presented with heart failure for the first time may have severe clinical signs requiring aggressive treatment (eg, with additional afterload reducers or temporary ventilatory assistance) that more typically would be reserved for those patients refractory to standard treatment.” (Keene, et al., 2019)
The researchers found that the concentration of CoQ10 in the myocardial tissue was significantly lower than those in the healthy control, and the dogs without signs of heart failure in B1 and B2. Some of the dogs were receiving medications, but the medications being given are not known to have an adverse effect on CoQ10.
“An overall significant difference was found among the four disease groups in the myocardial concentrations of total Q10 with Stage C having the lowest concentrations. (p = 0.0035), ubiquinol (p =0.029) and ubiquinone (p = 0.0008), respectively (Figure 1A–C). Post-hoc analysis revealed a significantly lower concentration of total Q10 in dogs with CHF (stage C) compared to each of the other groups: CON dogs (p = 0.0089), B1 dogs (p = 0.0018) and B2 dogs (p =0.0054). The oxidation rate of Q10 was not statistically different among the groups (overall 7 lp = 0.076, Figure 1D). Ubiquinol was lower in stage C dogs compared to each of the other groups: CON ( = 0.022), B1 (p = 0.044) and B2 (p = 0.013, Figure 1B) and the same held true for ubiquinone with a significantly lower concentration found in dogs with stage C disease compared to CON (p = 0.0104), B1 (p = 0.0001) and B2 (p = 0.008) dogs (Figure 1C).” (Christiansen, et al., 2021)
One thing of note is that in measuring citrate synthesis activity they did not find a difference between the healthy and the diseased dogs. This is significant because it demonstrates that the decreased level of CoQ10 in the tissue samples was not because of decreased Mitochondrial Density. This was contrary to what the researchers had hypothesized would occur. There was however an association with age.
The decreased levels of CoQ10 are consistent with the results of studies conducted on human patients suffering from various heart conditions such as ischemic heart disease, and dilated cardiomyopathy.
August 2022 Update
In a more recent study (randomized, double-blinded, placebo-controlled) we included dogs with varying stages MMVD receiving a daily dose of 200 mg (100 mg twice a day) or an organoleptically matched placebo for three months.
While cardiac biomarkers did not improve there was a significant decrease in systemic inflammation as measured by the percentages of neutrophil and lymphocytes. There was also an increase in CoQ10 concentration.
While that might not seem to be that important decreasing the level of inflammation could possibly result in longer expected survival times and quality of life, which should be the next step in evaluating the efficacy of CoQ10 supplementation.
Hopefully there will be other studies on other heart conditions to see if there is a similar effect in dogs.
Now the goal of the study wasn’t to demonstrate whether providing more CoQ10 through either food or supplements will actually help prevent, treat, slow disease progression, or improve the quality of life, of those suffering from MMVD, or Congestive Heart Failure. There are some human studies that do show positive effects and there are some that show no effect.
What the study does demonstrate is that there is a need to further research on whether supplementing with CoQ10 will help. Some of the authors of the current study did previously publish a study and found that supplementing with CoQ10 for 3 weeks “did not significantly improve echocardiographic indices of MMVD severity, circulating cardiac biomarkers, or owner perceived QoL compared to placebo” (Christiansen, et al., 2020). This was only a 3-week study with 19 dogs and to truly show whether it is beneficial or not will take significantly longer studies with more statistical power. This is also something that the researchers mention. This is something that will take time probably several years.
That being the case CoQ10 has been shown to be safe in dogs at levels as high as 6000 mg per kg per day.
While the science is still out the cost of supplements with CoQ10 or foods high in CoQ10 is relatively low, while the potential benefits are high. This is especially true if your dog is a breed predisposed to various heart conditions. Below is a list of foods with published data regarding CoQ10 content. It is all too easy to swap out treats or toppers with low or no CoQ10 for treats and toppers high in CoQ10.
CoQ10 Content of Foods
There really isn’t much data on the actual CoQ10 content of foods especially when it comes to many of the things we feed our pets.
|CoQ10 Content MG/KG
|CoQ10 Content MG/KG
|Mackerel Red Flesh
|Chicken Egg Yolk
(Pravst, et al., 2010)
CoQ10 is also found in small amounts in some vegetables, oils, nuts, and seeds.
Keene, B. W., Atkins, C. E., Bonagura, J. D., Fox, P. R., Häggström, J., Fuentes, V. L., Oyama, M. A., Rush, J. E., Stepien, R., & Uechi, M. (2019). ACVIM consensus guidelines for the diagnosis and treatment of myxomatous mitral valve disease in dogs. Journal of veterinary internal medicine, 33(3), 1127–1140. https://doi.org/10.1111/jvim.15488
Christiansen, L. B., Morsing, M. K., Reimann, M. J., Martinussen, T., Birlie, Z., Schou-Pedersen, A., Lykkesfeldt, J., & Olsen, L. H. (2020). Pharmacokinetics of Repeated Oral Dosing with Coenzyme Q10 in Cavalier King Charles Spaniels with Myxomatous Mitral Valve Disease. Antioxidants (Basel, Switzerland), 9(9), 827. https://doi.org/10.3390/antiox9090827
Christiansen, L.B.; Reimann, M.J.; Schou-Pedersen, A.M.V.; Larsen, S.; Lykkesfeldt, J.; Olsen, L.H. Depleted Myocardial Coenzyme Q10 in Cavalier King Charles Spaniels with Congestive Heart Failure Due to Myxomatous Mitral Valve Disease. Antioxidants 2021, 10, 161. https://doi.org/10.3390/antiox10020161
Pravst, I., Zmitek, K., & Zmitek, J. (2010). Coenzyme Q10 contents in foods and fortification strategies. Critical reviews in food science and nutrition, 50(4), 269–280. https://doi.org/10.1080/10408390902773037