“Good cholesterol’ particles may have a role in Alzheimer’s prevention

First-ever study to measure high-density lipoprotein particle numbers in spinal fluid led by Keck School of Medicine of USC

Medical guidelines meant to reduce risk for heart disease focus on levels of cholesterol in the blood, including low-density lipoproteins (LDL), labeled “bad cholesterol,” and high-density lipoproteins (HDL), labeled as “good.” Now, a new study suggests an important connection between good cholesterol particles in cerebrospinal fluid and brain health as well.

Researchers at the Keck School of Medicine of USC took samples of cerebrospinal fluid from people aged 60 and older and measured the amount of small HDL particles in each sample. The team found that a higher number of these particles in the fluid is associated with two key indicators that the particles might have a protective effect against Alzheimer’s disease.

One indicator is better performance on cognitive tests. The other indicator is higher circulating levels in the cerebrospinal fluid of a particular peptide — like a protein, but smaller — called amyloid beta 42. Although that peptide contributes to Alzheimer’s disease when it misfolds and clumps onto neurons, an increased concentration circulating around the brain and spine is actually linked to lower risk for the disease.

“This study represents the first time that small HDL particles in the brain have been counted,” said Hussein Yassine, M.D., an associate professor of medicine and neurology at the Keck School of Medicine of USC. “They may be involved with the clearance and excretion of the peptides that form the amyloid plaques we see in Alzheimer’s disease, so we speculate that there could be a role for these small HDL particles in prevention.”