One shot — that’s all scientists think it might take to permanently reduce the risk of heart attacks in humans by up to 90 percent.
How? Researchers with the Harvard Stem Cell Institute and University of Pennsylvania found a way to permanently reduce cholesterol levels in mice, a factor that can be related to heart attacks, with just one injection. This “genome-editing” approach, according to the Harvard Gazette, is something the scientists think could reduce heart attacks in humans by 40 to 90 percent, but clinical trials to see how it works in humans still could be a decade away.
“For the first iteration of an experiment, this was pretty remarkable,” Kiran Musunuru with Harvard told the Gazette.
Scientists achieved this permanent cholesterol reduction in mice by altering a liver gene that was previously identified as a cholesterol regulator. In humans, if this gene was mutated in one way, it seemed to be associated with higher cholesterol levels and subsequent heart attacks. Conversely, a different mutation in the gene identified in 3 percent of the population, according to the Gazette, seemed to result in lower cholesterol levels and fewer heart attacks. This latter mutation is what the researchers sought to emulate.
“Our reasoning was that nature has already done the experiment; you have people who have won the genetic lottery,” Musunuru said. “They are protected from heart attack, and there are no known adverse consequences. So that led us to reason that if we could find a way to replicate this, we could significantly protect people from heart attack.”
Put simply, the scientists created a break in the DNA of this gene in mice, which was then repaired in a way that reflected the mutation that would support better cholesterol levels.
“It could have had no effect, but it turned out to have a dramatic effect,” Musunuru said of the experiment. “Within three to four days of delivering the system into the liver, the majority of the PCSK9 gene copies in all of the liver cells were disrupted, knocked out. And what we hoped to see was much less of the protein product in the bloodstream, which is what we saw.”
Musunuru speculated that if they could do similar things with the same results in the human version of the gene, then this therapy would be “something like a vaccination.”
“As a cardiologist, what I find most tragic is when a 55-year-old person, with a family, in the prime of life, still working, out of the blue has a heart attack and drops dead,” Musunuru continued, according to the Gazette. “The public health implications are not trivial. Heart attack is a killer of the elderly, but there are many 50-, 60-, 70-year-old men and women dying of heart attacks.”
These findings were published in the journal Circulation Research.
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