Heart disease is responsible for a quarter of American deaths every year, killing about 647,000 people annually. Worldwide, it's the leading cause of death. That's why every year, billions of dollars fund cardiovascular research. The National Institutes of Health alone have put over $2 billion into cardiovascular research each year since 2016. So far, research has revealed ways to prevent cardiovascular disease through diet and exercise, but scientists are hunting for a pill to help keep blood vessels healthy. That pill might turn out to be a supplement called MitoQ that targets cells' mitochondria.
Turning Back Time
As people age, so do their hearts and blood vessels. Artery walls thicken, slowing the exchange of nutrients and waste in the blood and leading to higher blood pressure. This makes the heart work harder. As a result, it might not be able to pump blood through the body as well as it used to. These changes happen because of oxidative stress, damage caused by too many free radicals. Free radicals are oxygen atoms with unpaired electrons and form all the time in the body. They're waste products from common chemical reactions.
But too many free radicals can damage cells. This is because free radicals' unpaired electrons react quickly with those of other atoms or molecules. Electrons are negatively charged particles that orbit atoms in layers called shells. Atoms are most stable when their outer shell is filled with the maximum amount of electrons. Because free radicals have unpaired electrons, these atoms quickly react with others to fill their outer layer. This reactivity then causes too many free radicals to circulate, which can damage proteins, fats and even DNA.
Free radicals can come from inside the body or from outside sources like industrial chemicals and air pollutants. But within the body, researchers are interested in free radicals that come from mitochondria. At the University of Colorado Boulder, researchers have shown that targeting mitochondria with a commercially available antioxidant supplement might reverse some of this damage. The FDA-approved supplement, MitoQ, contains an enzyme engineered to cling to mitochondria and prevent oxidative stress.
Preventing oxidative stress in blood vessels would improve cardiovascular health.
While the body naturally produces antioxidants that help keep those free radicals in check, people can also obtain antioxidants from food. Because of this, scientists have long been interested in antioxidant supplements to prevent disease. But, most clinical trials featuring antioxidant supplements haven't shown clear benefits. MitoQ, however, targets a specific cellular component, which may be where it differs from other supplements.
The Clinical Trial
The study, funded by the NIH and MitoQ, tested whether the supplement could improve blood flow through the arteries. The researchers had already seen MitoQ reduce free radicals and reduce artery stiffening in older mice, but this time they tested the theory on humans. Ten healthy adults between 60 and 79 years old with thickening arteries took 20 milligrams of MitoQ each day for six weeks, while ten more took an identical-looking placebo capsule. The participants did not know which group they had been assigned to; Placebo or MitoQ.
Participants took either MitoQ or an identical capsule to see if it improved blood vessel health.
After the six weeks elapsed, a researcher blind to the participants' experimental condition took blood samples and measured blood flow through the brachial artery, a major blood vessel in the upper arm. Next, the researchers switched the two groups: those who had received placebo at first then took MitoQ for the next six weeks, and those who had taken MitoQ now followed by the placebo. Then the researchers repeated the tests.
They found that after taking MitoQ for six weeks, the lining of participants' brachial arteries functioned better. Blood vessel dilation improved by 42 percent, accommodating greater blood flow. According to the lead author, postdoctoral researcher Matthew Rossman, if maintained over time, this improvement could lead to a 13 percent reduction in heart disease. These results, published in the journal Hypertension in 2018, showed that an antioxidant targeting mitochondria could be a powerful tool against cardiovascular disease.
This study only tested the effects of MitoQ on 20 individuals. Before anyone can recommend MitoQ for heart disease prevention, scientists need to conduct more clinical trials with a greater number and diversity of participants. For now, the best way to prevent cardiovascular disease is by maintaining a healthy diet and regular exercise.
For now, people can turn to healthy foods and regular exercise to reduce the effects of aging on blood vessels.
Although many studies show that exercise and eating healthy foods are effective at maintaining a healthy cardiovascular system, “the reality is, at the public health level, not enough people are willing to do that," Doug Seals, an author on the study and researcher specializing in the physiology of aging told UC Boulder. And for many people, the demands of daily life might get in the way of exercise and regular, healthy meals. Because it's unlikely that will change, scientists continue to search for other ways to reverse blood vessel aging.