Researchers used a highly advanced scanning tool to look at the proteins inside individual cells taken from the main blood vessel—the aorta—of both healthy mice and mice with a genetic condition called Marfan syndrome. By zooming in on these proteins, they could easily map out all the different types of cells in the blood vessel, including seven highly specific kinds of muscle cells. The team discovered that the exact mix of cells and their proteins shifted significantly depending on the animal’s sex and whether it had the disease. When comparing this new approach to traditional genetic tests, the protein scan proved far better at spotting those subtle, hidden differences between the muscle cells. After double-checking their results with special glowing dyes to confirm their accuracy, the scientists proved that this new method of analyzing single-cell proteins is an incredibly powerful tool for uncovering exactly why blood vessels fail, paving the way for better ways to study complex diseases in the future.