When Good Cholesterol Goes Bad

In pre-clinical studies, the team discovered that HDL with a high content of free cholesterol is likely dysfunctional. To validate their findings, they are currently at the halfway point of the NIH-funded Houston Heart Study with 400 patients with a range of plasma HDL concentrations. “The most surprising finding from our study, thus far, is that there is a strong link between the amount of free cholesterol in HDL and how much of it accumulates in white blood cells called macrophages, which can contribute to heart disease,” emphasized Pownall. While it was previously thought that the transfer of free cholesterol to HDL was beneficial for heart health by removing excess cholesterol from tissues, the data shows that in the context of high plasma HDL concentrations, the reverse is true—free cholesterol transfer from HDL to the white blood cells in blood and tissues could actually raise one’s risk for cardiovascular disease. Once they reach their immediate goal of showing that excess free cholesterol in HDL is associated with excess cardiovascular disease, the research team plans to develop new diagnostics and treatments for managing heart disease, as well as use HDL-free cholesterol as a biomarker to identify patients requiring HDL-lowering therapies.