30-Year-Old Antibiotic Offers Hope for Patients With Huntington's Disease
"I think the importance of this study is not necessarily that this drug will be useful in humans, although it may turn out to be, but it shows that drug compounds can potentially be helpful," says Christopher Ross, MD, PhD, who was not involved with the study.
"This drug by itself may not have a huge impact, but if you can get two or three drugs acting in different ways, the cocktail might be quite effective," says Ross, professor of psychiatry and neuroscience at Johns Hopkins University and chair of the Medical and Scientific Advisory Committee of the Huntington's Disease Society of America (HDSA).
HDSA spokeswoman Joyce Hammel agrees. "This is very exciting, because it is the first time we have seen anything delay the onset of disease and increase life expectancy in an animal model," she tells WebMD. "We are hoping that several discoveries like this will result in a synergistic approach to the cure of HD." The cocktail approach appears the most likely, she says, even though there is only one gene that causes the disease, because there is a very complex progression from the gene to actual cell death and symptoms.
Huntington's disease is caused by a genetic disorder that prompts nerve cell death in the region of the brain that controls movement. A little over a year ago, Friedlander and colleagues reported that an enzyme called caspase-1 is activated in the brains of humans and mice with the disease, and that blocking caspase function delays disease onset and mortality in mice. The Harvard researchers used minocycline in their most recent studies because it is known to inhibit caspase-1 and caspase-3.
The antibiotic was found to significantly slow Huntington's disease progression in the mouse model, but Friedlander says it is not yet clear why. "We don't exactly know why minocycline works, but it is not the antibiotic effect," he says. "We believe there are other properties involved, but we don't know what they do."
While he agrees the findings are exciting, Ross would not speculate on when an effective therapy might be available for the treatment of Huntington's disease. "I am very hopeful that we will soon see some sort of therapy, but I wouldn't want to say when," he says. "We still have a lot to learn."