US doctors have developed a new gene therapy involving a one-off injection of ‘nanolipids’ to prevent heart attacks.
The researchers were hoping to trial the therapy within the next three years in people with a rare genetic disorder that made them prone to heart attacks in their 30s and 40s, the Guardian newspaper reported on 11 May.
Homozygous familial hypercholesterolaemia (FH) caused very high cholesterol levels and affected up to one in 160,000 people.
In the trial, patients would be given a one-off injection of nanolipids – tiny, fatty spheres – into the bloodstream, which would home in on liver cells. The nanolipids would infiltrate liver cells and release a gene-editing tool called Crispr-Cas9, which would locate a gene called PCSK9 and turns it off. Silencing 30-40% of PCSK9 – which was involved in making low-density lipoprotein (LDL), the so-called ‘bad’ cholesterol – should protect against heart attack, the Guardian wrote.
As well as treating those with FH, the therapy could be relevant to any adult at risk of a heart attack, according to Sekar Kathiresan, a cardiologist and geneticist who has resigned from Harvard Medical School and the Center for Genomic Medicine at Massachusetts general hospital to run a start-up called Verve Therapeutics, which will develop the new technology.
However, while Kathiresan hopes the new therapy will cut the regime of blood thinners, cholesterol-lowering statins and pills for high blood pressure which people who are a risk of heart attack are typically put on, other researchers point to the risks of gene therapy.
These included difficulties in controlling how many genes were turned off and ensuring only target genes were edited.
“The problem with all gene therapy is that you cannot withdraw people from treatment,” said Sian Harding, professor of cardiac pharmacology at Imperial College London, in the Guardian. “It’s a problem if it’s not controllable and not reversible.”