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ex Member
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Join Date: Aug 2006
Location: New York
Posts: 93
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ex Member
Join Date: Aug 2006
Location: New York
Posts: 93
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The theory is based on the study concerning "Blood-brain barrier dysfunction". The full original reference is not given above, and appears to be Annals of Neurology [2005] 57 (2) : 176-179 (Kortekaas R, Leenders KL, van Oostrom JC, Vaalburg W, Bart J, Willemsen AT, Hendrikse NH.)
The decrease in blood barrier function is quite small (about 18%), and due to the statistical error allowed for may be less than 10%. This would not explain the as much as 90% reduction in function of the enzymes involved in dopamine biosynthesis that is known to occur in Parkinson's Disease.
The study compares the results of people with Parkinson's Disease against a control group. However, there is no indication in the study that the control group was age controlled. Given that the average age of people with Parkinson's Disease is above average, the study may merely indicate that blood brain barrier function deteriorates with age.
This was subsequently proven in another study that has been published since then : Clinical Pharmacological Therapeutics [2006] 79 (6) : 540-54 (Toornvliet R, van Berckel BN, Luurtsema G, Lubberink M, Geldof AA, Bosch TM, Oerlemans R, Lammertsma AA, Franssen EJ). They used exactly the same methods using verapamil, and demonstrated the age related deterioration in function of the blood brain barrier.
The suggestion that the blood brain barrier function deteriorates with age and thereby increases the likelihood of Parkinson's Disease is inconsistent with the known prevalence of Parkinsons' Disease.
In the following newly published study it was found that virtually none of the people between the ages of 110-119 had Parkinson's Disease : Journal of American Geriatric Society [2006] 54 (8] : 1237-1240 (Schoenhofen EA, Wyszynski DF, Andersen S, Pennington J, Young R, Terry DF, Perls TT.)
At the age of nearly 120, their blood brain barrier function should have greatly deteriorated. and if the theory was correct, thereby make them most prone to Parkinson's Disease, yet in the oldest of people Parkinson's Disease is virtually unknown.
Of the dozen or so toxins that are known to be able to cause Parkinson's Disease, most of them are not commonly encountered. The only exception is carbon monoxide which has never been shown to result in Parkison's Disease unless the carbon monoxide poisoning has resulted in a coma.
The other inconsistency with the theory is that if toxins via reduced blood brain barrier function resulted in Parkinson's Disease, then why doesn't it result in all other potential neurological disorders, because there are dozens of cell types in the nervous system. The dopaminergic neuron is only one of them. Many people with Parkinson's Disease suffer additional problems that could be a result of the dysfunction of certain nerve cell types, such as dementia. However, many people with Parkinson's Disease do not. Thisis obviousy inconsistent with the theory of Parkinson's Disease resulting from a general toxicity that would affect the nervous system generally.
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