You might want to take a look at the CCSVI Alliance website:
In particular the page on preserving and enhansing endothelial health:
http://ccsvi.org/index.php/helping-myse ... lialhealth
According to the CCSVI Alliance website Endothelium is:
The thin layer of cells lining the inner wall of all blood vessels. The endothelium helps regulate blood pressure, coagulation, and inflammation, and is considered a compelling research candidate for investigating the relationship between vascular damage and immune response in MS.
I think (though I'm not a medical expert) that when you hear people talking about the "the blood brain barrier" they're talking about the endothelium.
I am a big fan of being tested for Vitamin D level and then supplementing to get your level up in the top third of the normal range. There are studies that show that MS relapse rates drop as vitamin D levels rise. My levels were scarily low when first tested. I also try to eat less than 15 mg of saturated fat a day, which is not very much (see the Swank Diet for more information). And I use Olive Oil as my substitute for other oils and fats, (no butter or margerine for me). I know exercise is really important but I have not managed to do much of that so far, due to MS fatigue. Maybe soon I'll add that to my regimen.
Hopefully other people will respond with more specific information.
p.s. I wrote this last night and then realized this morning that I'd fallen asleep and hadn't pushed send, so my apologies if I'm repeating information others have already posted.