A controversial theory connecting narrowed blood vessels to multiple sclerosis doesn't stand up to independent verification, authors of a new study argue.
A controversial theory arguing that multiple sclerosis (MS) is caused by narrowing of the veins that carry blood back to the heart from the brain and spine has failed to stand up to independent verification, argue the authors of a new study in Archives of Neurology.
The theory that narrowed blood vessels, or chronic cerebrospinal venous insufficiency (CCVI), cause the vast majority of MS cases was proposed in 2009 by a team of Italian researchers led by Paolo Zamboni, MD. The idea is that the constriction of the vessels forces some of their blood back into the brain tissue, causing inflammation and leading to the balance and muscle problems seen in MS.
The Italian team found that CCSVI was common in MS patients, but rare in people who do not have the disease. However, as the authors of the new study detail, three independent studies published since have found no such link between CCSVI and MS. (Critics have also alleged that the original Italian study was poorly designed and vulnerable to investigator bias.)
Since Zamboni’s team published its findings, MS patients have sought out procedures to expand their blood vessels, and some doctors have obliged them. But the procedures, which usually involve inflating a balloon in the patient’s veins, bring along the possibility of bleeding and infection. The new study’s authors argue that, given the absence of compelling proof of the connection between CCSVI and MS, such procedures should not be pursued.
Around the Web
Are narrow blood vessels to blame in MS? [Reuters]
Chronic Cerebrospinal Venous Insufficiency and Multiple Sclerosis (Abstract) [Archives of Neurology]