Nutrient - Vitamin D3 and curcumin may help clear Alzheimer's plaques
Patients with Alzheimer’s disease (AD) suffer from brain amyloidosis related to defective clearance of amyloid-ß (Aß) plaques by the innate immune system. Macrophages of a majority of AD patients do not transport Aß into their endosomes and lysosomes properly, and AD monocytes do not efficiently clear Aß from the sections of AD brain. However, a new study published in the July issue of the Journal of Alzheimer’s Disease, has found that vitamin D3, either alone or in combination with curcumin, may help stimulate the immune system to clear these plaques from the brain.
The UCLA scientists and colleagues carried out their research by isolating monocytes from the blood of AD patients and healthy controls. Monocytes are precursors to the phagocytic immune cells macrophages, which are the prime defence mechanism against waste products in the body, including amyloid plaques.
With a view to improving the innate immune system of AD patients, the researchers studied immune stimulation of the resulting macrophages by incubating them with Aß, vitamin D3 and a selection of natural and synthetic curcuminoids. What they discovered was that vitamin D3 strongly stimulated Aß phagocytosis and clearance, while protecting against apoptosis. Interestingly, the macrophages of some of the AD patients displayed additive phagocytic effects in the presence of certain synthetic curcuminoids, whereas others did not. Those stimulated by the curcuminoids were labelled Type I and those displaying no additive effects from the presence of curcuminoids were named Type II.
In addition, the scientists investigated the mechanisms behind the observed effects by carrying out a number of binding studies. The results indicated that vitamin D3 had preference for binding to the genomic pocket of the vitamin D receptor, resulting in increased uptake and absorption of Aß by macrophages, whereas the curcuminoids were found to bind to a different site. Previous work by the team suggest that the curcuminoids act by restoring the expression of certain genes that are associated with the immune system’s ability to ingest amyloid beta.
Overall, the researchers concluded that vitamin D3 is a promising hormone for AD immunoprophylaxis, because in Type I macrophages combined treatment with vitamin D3 and curcuminoids has additive effects, and in Type II macrophages vitamin D3 treatment is effective alone.
“We hope that vitamin D3 and curcumin, both naturally occurring nutrients, may offer new preventive and treatment possibilities for Alzheimer’s disease,” said Dr. Milan Fiala, one of the authors of the study. While no definitive dosage guidelines for vitamin D and curcumin can be offered at the moment, larger studies are planned.