Ron and others,

I’ve been puzzled for a while by the correlation between Parkinson’s disease, low levels of B12 vitamin and high levels of Homocysteine.

There is for example a clinical trial going on by the American institute of health to investigate the effect of b12 supplementation in PD on homocysteine levels.

Levodopa is metabolized by COMT to 3-O-methyldopa. This conversion requires the methyl-donor S-adenosylmethionine. After S-adenosylmethionine donates its methyl- group, it is converted to S-adenosylhomocysteine and then to homocysteine.

There is research going on at the American Society of Hematology about elevated levels of homocysteine being responsible for damage to the blood-brain barrier integrity in mice

Elevated levels of plasma homocysteine are known to correlate with increased risk of cardiovascular and Alzheimer diseases.

On a hyperhomocysteinemic diet, cystathionine beta-synthase (Cbs)–heterozygous mice develop hyperhomocysteinemia. BBB permeability was measured and was found to be 25% greater.

Joop Oele (Netherlands)