Study in Nature: MicroRNAs hold promise for treating diseases in blo...( A newly discovered mechanism control...),Health

A newly discovered mechanism controls whether muscle cells in blood vessels hasten the development of both atherosclerosis and Alzheimer's disease, according to an article published online today in the journal Nature.

The study was led by the Gladstone Institute of Cardiovascular Disease (GICD) in San Francisco, with key contributions from the Aab Cardiovascular Research Institute at the University of Rochester School of Medicine and Dentistry.

Thanks to stem cells, humans develop from a single cell embryo into a complex being with about 250 unique cell types. As the fetus develops, cells divide and multiply (proliferate) in many generations and specialize (differentiate) with each generation until millions of functional cells result (bone, nerve, blood, skin, muscle, etc.). To serve specific roles in the body, some stem cells also switch back and forth between primitive, rapidly proliferating precursors and their mature, functioning, non-proliferating counterparts, a quality called "plasticity."

Among the most "plastic" of cells are vascular smooth muscle cells (VSMC), which form in layers around blood vessels, and by contracting or relaxing, regulate blood pressure. Because VSMC surround blood vessels that are continually becoming clogged by atherosclerosis, they must be ever ready to grow along with the vessel as it attempts, by growing, to remain open to blood flow despite fatty deposits and inflammation. If these efforts fail, heart attack or stoke may occur. Each time a vessel grows to avoid a clog, the VSMC surrounding it must grow too by reverting to their high-growth precursor form. Once a vessel reaches its growth limit, however, the growth that once kept vessels open begins adding to clogs by thickening vessel walls.

Past studies in Rochester have shown that transition of VSMC from fast-proliferating stem cells to mature cells and back is largely controlled by two proteins, myocardin and serum response fact
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