The herb rosemary has long been linked with memory: “There’s rosemary, that’s for remembrance,” says Ophelia in Shakespeare’s Hamlet. So it is fitting that researchers would study a compound found in rosemary and sage—carnosic acid—for its impact on Alzheimer’s disease. In the disease, which is the leading cause of dementia and the sixth leading cause of death in the US, inflammation is one component that often leads to cognitive decline. Carnosic acid is an antioxidant and anti-inflammatory compound that works by activating enzymes that make up the body’s natural defense system. While pure carnosic acid is too unstable to be used as a drug, scientists at Scripps Research have now synthesized a stable form, diAcCA. This compound is fully converted to carnosic acid in the gut before being absorbed into the bloodstream.

The early diagnosis of Alzheimer’s disease (AD) through the detection of p-tau proteins in the blood is less disease-specific than assumed since these biomarkers are also elevated in the blood of people with amyotrophic lateral sclerosis (ALS). Therefore, more specific tests should be developed and validated as screening tests for AD in the general population. These were the findings of a multi-center study with 385 subjects led by the University Medicine Halle in cooperation with the departments of Neurology at the Universities of Milan (Italy), Mannheim and Ulm. The paper is published in “Nature Communications”.

A new Northwestern Medicine study publishing in Nature Medicine suggests a promising alternative to previous attempts to remove the sticky, toxic amyloid beta plaquest from brains with Alzheimer's Disease: enhancing the brain’s own immune cells to clear these plaques more effectively.

The findings could reshape the future of Alzheimer’s treatments, shifting the focus from simply removing plaques to harnessing the brain’s natural defenses.

The study is the first to use a cutting-edge technique called spatial transcriptomics on human clinical-trial brains with Alzheimer’s disease. The technique allows scientists to pinpoint the specific spatial location of gene activity inside a tissue sample. 

By analyzing donated brain tissue from deceased people with Alzheimer’s disease who received amyloid-beta immunization and comparing it to those who did not, the scientists found that when these treatments work, the brain’s immune cells (called microglia) don’t just clear plaques — they also help restore a healthier brain environment.