In diseases like cancer, diabetes, rheumatism and stroke, a disorder develops in the blood vessels that exacerbates the condition and obstructs treatment. Researchers at Karolinska Institutet now show how blood vessels can normally change their size to create a functional circulatory system and how vascular malformation during disease can occur. In the study, published in Nature Cell Biology, the researchers managed to treat vascular malformation in mice, a discovery of potential significance to numerous vascular diseases.