In 2009, Dr. Paolo Zamboni from the University of Ferrara in Italy put forth the idea that CCSVI (chronic cerebrospinal venous insufficiency), a reported abnormality in blood drainage from the brain and spinal cord, may contribute to nervous system damage in MS. He also published results from a study which demonstrated that CCSVI was present in all the individuals with MS who he examined.
To quickly investigate this potential lead, the National MS Society and MS Society of Canada collaborated to fund seven research projects, for a total of $2.4 million, at research centers in the U.S. and Canada focusing on whether there was a link between vein drainage and MS.
Following the release of Dr. Zamboni’s findings, additional studies have been conducted worldwide, and have led to conflicting conclusions. Some researchers have shown an association between vein abnormalities and MS while others have not.
The latest and most thorough studies do not show an association between CCSVI and MS.
A growing body of evidence on the prevalence of CCSVI among people living with MS and people who do not have MS suggest that CCSVI is not linked with MS. Researchers suggest that discrepancies in results may be attributed to inconsistencies in imaging techniques, training of personnel, the interpretation of results, and even on the hydration status of people undergoing testing. Some studies also challenge the validity of the proposed diagnostic criteria for CCSVI.
The FDA issued a safety communication about procedures to treat CCSVI.
The proposed treatment for CCSVI, sometimes referred to as “liberation therapy,” is an angioplasty procedure, which involves opening blocked or narrowed veins by inflating a small balloon or inserting a stent to allow for better blood flow and improve drainage of blood from the brain. In May 2012, the U.S. FDA issued a safety communication about procedures to treat CCSVI in people with MS.
Virtually all FDA-approved disease-modifying MS therapies have their own risk/benefit profiles. The difference is that these therapies have been shown, through large-scale, controlled clinical trials, to significantly reduce MS disease activity in certain individuals.
A clinical trial is underway in Canada.
The National MS Society continues to invest in research related to blood flow in the brain and vascular changes that may occur in MS.
Here are some examples of recently funded projects:
• Noting that MS lesions in the brain may change blood flow, researchers at the University of Texas, Dallas led by psychologist Bart Rypma, PhD, are being funded to investigate biological mechanisms in the brain that may underlie MS “brain fog” as a path toward finding solutions to cognitive problems in MS. The team is investigating whether blood flow changes limit the availability of oxygen to brain cells, resulting in cognitive slowing. They are using advanced MRI techniques and psychological testing, and measuring blood oxygen levels, cerebral blood flow, and other factors to assess the possible relative contributions of each system to MS-related cognitive slowing. This project will yield new discoveries regarding the mechanisms that may be responsible for cognitive slowing in MS and guide the search for solutions to cognitive problems.
• University of Miami researchers led by Hong Jiang, MD, PhD, are studying blood vessels at the back of the eye of people with MS as a window to better understand nerve damage and MS progression, because the location of the brain’s capillaries make them difficult to see and assess directly. The back of the eye (retina) has a vascular system and since it is an extension of the brain’s circulatory system, it may prove an ideal way to study blood circulation in the brain. The team is using advanced imaging devices to study microvessel abnormalities and neural damage in the retinas of people with all types of MS and people without MS. They team will determine whether abnormalities precede or contribute to MS-related neural damage. This research may increase understanding of the progression and underlying neural damage mechanisms of MS, which could set the stage for more effective and beneficial therapies.