A light micrograph cross-section showing cholesterol-containing plaque in a heart arteryNIGEL DOWNER/SCIENCE PHOTO LIBRARY The prospects for a one-time treatment that reduces the risk of heart disease for the rest of a person’s life just got brighter. In an initial trial, a single dose of a CRISPR gene-editing therapy lowered cholesterol levels without any serious side effects. The “Heart-2” trial – organised by the biotech company Verve Therapeutics in Boston – involved 14 people who either had an inherited condition leading to very high cholesterol or had developed heart disease at a young age. While this was an early-stage trial…