Researchers remain perplexed as to what causes dementia and how to treat and reverse the cognitive decline seen in patients. In a first-of-its-kind study, researchers at the Medical University of South Carolina (MUSC) and Beth Israel Deaconess Medical Center (BIDMC), Harvard Medical School discovered that cis P-tau, a toxic, non-degradable version of a healthy brain protein, is an early marker of vascular dementia (VaD) and Alzheimer’s disease (AD). Their results, published on June 2 in Science Translational Medicine, define the molecular mechanism that causes an accumulation of this toxic protein. Furthermore, they showed that a monoclonal antibody (mAb) that targets this toxic protein was able to prevent disease pathology and memory loss in AD- and VaD-like preclinical models. Additionally, this treatment was even capable of reversing cognitive impairment in an AD-like preclinical model.