UC Irvine researchers identified dopamine loss in a key brain region as a driver of memory decline in Alzheimer’s disease.

Restoring dopamine levels, including with the drug Levodopa, improved memory function in preclinical models.

Findings suggest a promising new treatment pathway targeting brain circuits, not just toxic proteins.

The Center for Disease Control estimates nearly 50% of the U.S. population has either prediabetes (38%) or type 2 diabetes (T2D). Vitamin D deficiency is common in individuals with T2D with a prevalence of more than 80%. Past studies have reported pre-diabetic adults on 4000 IUs vitamin D3/d (median of 2.5 years) received no benefit in reducing progression to type 2 diabetes (T2D) compared to placebo. While other studies have shown participants receiving vitamin D who maintained certain levels of serum 25-hydroxyvitamin D [25(OH)D], resulted in approximately 52% and 71% risk reductions.

In the latest issue of JAMA Network Open, Dawson-Hughes et al., examined four common vitamin D receptor (VDR) polymorphisms (common genetic variations in DNA sequences) and observed that subjects with the vitamin D receptor (VDR) ApaI AA alleles, received no benefit from vitamin D treatment. However, subjects with ApaI AC and CC genotypes showed a 19% decreased risk of progressing to T2D. Polymorphisms are associated with chronic disorders including autoimmune diseases, diabetes, heart disease, deadly cancers and Alzheimer's disease. Polymorphisms also disrupt drug responses by alterations in enzyme function, drug transport and receptors.