Coenzyme Q₁₀
Part 2

An Antioxidant Drug

New discoveries

Based upon the ALS and Parkinson’s trials, it was hypothesized that a higher dosage of coenzyme-Q₁₀ might be more effective. A recent study by the Ferrante lab tested higher doses of coenzyme-Q₁₀. They used the same mouse model of HD as in the 2002 study. This model demonstrated many features of human HD, including time of onset and progression of symptoms. They also compared two commercially-available preparations of coenzyme-Q₁₀, one from a company called Tishcon and one from a company called Chemco. It is important to remember that coenzyme-Q₁₀ is a nutritional supplement and can be bought in many different prepared forms. Little is known about how each of these prepared forms may affect HD patients differently, and so it is useful to compare them. The researchers administered different doses of each substance, seeking an optimal dosage to treat HD.

Results showed that higher doses of coenzyme-Q₁₀ significantly slowed the progression of HD symptoms, such as declining motor performance and grip strength. Ferrante tested several different doses and found that 5000mg/kg/day was the most effective amount. It extended the lifespan in HD mice; those treated with coenzyme-Q₁₀ had a 25.3% longer lifespan compared to untreated mice. This is a major improvement over the 2002 study, in which HD mice that were treated with 400mg/kg/day of coenzyme-Q₁₀ only lived 13% longer than untreated ones. Moreover, HD mice treated with higher doses of coenzyme-Q₁₀ did not lose as much weight, have as much nerve cell death, or form as many huntingtin aggregates as untreated HD mice. Administering high doses of coenzyme-Q₁₀ to mice in the form of a pellet significantly raised the level in their bloodstream and nerve cells. These findings suggest that oral administration of the drug would be effective. Finally, high doses of coenzyme-Q₁₀ also reduced the amount of OH8dG in the brain. OH8dG is a molecule that appears in unusually high concentrations in the brains of HD patients, and is associated with oxidative stress in the nerve cell. In summary, this study shows that high doses of coenzyme-Q₁₀ can prevent some motor symptoms, prolong lifespan, and reduce oxidative stress and nerve cell death in HD mice.

Ferrante and collaborators also compared the effectiveness of the same two commercially available coenzyme-Q₁₀ preparations. They found that the supplement produced by Tishcon was 5 times more effective than another coenzyme-Q₁₀ supplement produced by Chemco. Both coenzyme-Q₁₀ preparations were given to the mice as a pellet, but 5 times as much of the coenzyme-Q₁₀ in the Tishcon pellet was absorbed into the bloodstream in comparison to the Chemco pellet. It is important to remember that coenzyme-Q₁₀ is a nutritional supplement and can be bought in many different prepared forms. Often there is little standardization and poor quality control for these supplements. Little is known about how each of these prepared forms may affect HD patients differently, and so it is useful to compare them.

In fact, the Cure HD Initiative (CHDI), a nonprofit drug development research organization for HD, has recently begun to work on creating treatments for HD using coenzyme-Q10. On August 2, 2006 CHDI announced a partnership with Edison Pharmaceuticals, Inc. Edison is a small company that specializes in drug developing for diseases related to problems with mitochondria, oxidative damage, and energy levels in the cell. This partnership will be an opportunity for Edison to specifically focus on oxidative damage in HD. The partnership hopes to develop a second generation coenzyme-Q10 molecule to be used to treat HD. Scientists at Edison Pharmaceuticals will contribute their expertise in the biology and pharmacology of free radicals and oxidative damage, while members of CHDI, Inc will contribute their expertise in HD and drug development.

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Last Modified: 05/22/2009

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