The Umeå scientists are not alone in calling into question the findings of the Italian research team. A study run by a German research group does not either support the Italian theory that the flow of blood to and from the brain contributes to the development of MS.
The two new studies question the wide-spread hypothesis that constrictions of veins, so-called chronic cerebro-spinal venous insufficiency (CCSVI), contribute to the development of MS. The studies are the first negative medical evidence regarding this hypothesis.
Previously an Italian research group has shown in a series of publications that deviations in the venous outflow (backward flow, reduced flow, altered flow) always occur in individuals with MS, but never in those who do not have MS.
The Italian research team has also published a study where a group of patients with MS underwent vascular surgery with the aim of improving their venous outflow. Two fatalities following such operations have attracted much publicity, as there are no randomized controlled studies of the procedure and the underlying theory has not been scrutinized by other research groups.
"The Italian theory is hard to accept for many reasons. For instance, there are no reports of increased incidence of MS in patients with conditions that impair venous outflow, such as following tumor operations in the throat. For many years, before the advent of magnetic camera technology, MS patients were also often examined using cerebral angiography, so-called skull coloring, a technique that should uncover these kinds of changes," says Peter Sundström, chief physician at the Neurology Clinic, University Hospital of Umeå.
The German research team studied venous blood flow from the brain using ultrasound – the same method used by the Italian research group. The study showed no reduced blood flow in MS cases compared with healthy controls.
The researchers used a magnetic camera (phase contrast MRI, PC-MRI) to meter the flow of blood from the brain. PC-MRI is regarded as a reliable way to measure the flow in blood vessels, for instance. The study focused on the flow in the internal jugular vein, vena jugularis interna. The flow of spinal fluid in the brain – which the Italian research group also maintains is lower in individuals with MS – was also studied.
In the study no differences were registered between people with MS and healthy control individuals regarding blood flow to the brain or blood flow from the brain via the internal jugular vein, or the flow of spinal fluid in the brain. The study cannot confirm the new Italian theory, and the findings do not support the assumption that operations that improve venous outflow from the brain can be used as treatment for MS.
MEDICA.de; Source: Umeå University