From http://www.vrp.com/art/583.asp?c=117...p.css&p=no&s=0

The other known benefit to the brain that proanthocyanidins offer derives from proanthocyanidins ability to protect collagen structures.1 Collagen and elastin are the proteins that serve as cement to hold together the cells that make up blood vessel walls. Proanthocyanidins inhibit enzymes such as hyaluronidase, collagenase and elastase that can break down the collagen structure of blood vessel walls.1 This fact is especially important for brain health, due to the blood-brain barrier.

Capillaries (the tiniest blood vessels that feed individual cells) in the brain are different from capillaries elsewhere in the body. All non-brain capillaries possess slit pores - openings between the patchwork quilt-like mosaic of cells which form blood vessel walls. These slit pores allow nutrient molecules to diffuse from the capillary blood into the fluid which bathes all cells, and thence into the cells themselves. Brain capillaries lack this feature, however. All the cells making up the brain capillary walls are tightly stitched together through their supporting collagen-elastin ground substance cement.2

Nutrient molecules can only pass from the capillary blood to the surrounding brain cells with the help of ATP energy-driven carrier molecules.2 These act like ferry boats to
take nutrients from the blood side of the capillary cell wall, through the capillary lining cell, to the outside of the capillary cell wall, where the nutrient molecules are then picked up by special non-neuronal brain cells called glial cells, which then pass the nutrients to the neurons (the electrically active brain cells) for their use. This blood-brain barrier provides a special degree of protection from toxins, as well as blood level fluctuations of nutrients that might disregulate key brain processes.2 This is especially important for neurons. While all other cell types create their own replacements our whole life long - e.g. new skin cells and intestinal lining cells every 3-5 days, new red blood cells every 4 months, even new bone cells over several years - our bodies create no new neurons after age two. Thus, brain cells are literally irreplaceable. Even if we live to be 100, we will still have the exact same original neurons we had at age two, minus those that died off along the way. Parkinsons disease occurs when 70-80% of a small group of dopamine-using neurons have died off in a brain region called the substantia migra. Thus, anything that safely and effectively preserves and protects the integrity of the blood-brain barrier, also preserves and protects the life, health and function of our precious, irreplaceable neurons.

Grape seed extract proanthocyanidins can protect the collagen-elastin cement that holds the brain capillary cells together, with no leaky holes from the damaging action of both free radicals and collagen-elastin dissolving enzymes that leak out from damaged or dying cells. Thus, proanthocyanidins are powerful protectors of blood-brain barrier integrity. The seamless, holeless integrity of the blood-brain barrier is the basis for the integrity of our brain structure and function. Autopsy studies have shown that various forms of brain disease and damage can literally create tiny holes in the blood-brain barrier .2 This allows toxins (such as neurotoxic pesticide residues on our food) and excesses of certain nutrients (such as sodium) to leak into brain cells, with results ranging from mild disruption of function (as in ADD) to neuronal death.

Proanthocyanidins are extremely safe, natural compounds found in many foods - although at levels too low to provide major benefit. Grape Seed Extract and Pine Bark Extract are the two main commercial sources of concentrated proanthocyanidins A proanthocyanidin called B2-3-O-gallate is present only in Grape Seed Extract, not in pine bark, and is the most powerful specificproanthocyanidin yet discovered.1 Grape Seed Extract is also significantly less expensive and so is arguably the best proanthocyanidin source. An economy level dose of proanthocyanidins is 30-50 mg per day, while 100 mg is a more truly therapeutic dosage. In Europe, where grape seed extract proanthocyanidins have been used clinically and studied for over 20 years, doses from 100 to 400 mg per day are routinely used. Proanthocyanidins are virtually non-toxic at any affordable dose, with grape allergy being the one possible cause for caution.1 JS