Higher levels of iron in one part of the brain and lower levels in another in patients with multiple sclerosis (MS) was associated with longer disease duration, more disability, and disease progression, according to a prospective study published online in Radiology on July 17.
The factors implicated in MS, a disease of the central nervous system, are both genetic and environmental, and research on all factors is ongoing. A growing area of interest is iron levels in the brain and changes in grey and white matter and how they relate to disease progression.
To investigate the role of iron levels in MS progression, a team of researchers recruited 600 MS patients, including 452 with relapsing-remitting MS and 148 with secondary progressive MS and 250 healthy controls who were matched by age and sex. On average, the age for participants with MS was 44.9 years and 45 years for healthy control participants. No significant age differences between men and women in the study groups were found.
To measure iron levels, the team used advanced MRI technology that calculates the presence of iron in different brain regions via magnetic susceptibility. An area of the brain that has more iron has a higher magnetic susceptibility; one with less iron has a lower susceptibility.
Compared with healthy controls, MS patients showed higher levels of iron in the basal ganglia—a group of brain structures essential in movement—and lower levels in the thalamus—an area of the brain that helps to process sensory input between certain brain structures and the spinal cord.
In participants with the progressive form of MS, lower levels of iron in the thalamus were associated with longer disease duration compared to those with relapsing-remitting MS or clinically isolated syndrome. This suggests iron-related thalamic damage starts earlier in the disease, the researchers hypothesized.
For both groups, higher iron content in the basal ganglia and lower iron content in the thalamus was linked to disability, a finding that persisted even after researchers accounted for brain volume changes in each individual structure of the thalamus. This pattern, researchers concluded, is an independent predictor of MS-related disability.
Using advanced MRI technology to measure iron levels in patients with MS could help identify those at higher risk of disability and disease progression. If used in clinical trials, the MRI technology could also help assess new drug therapies.