Chronic inflammation signals brain atrophy in children with MS: Study
MRI scans show nearly 75% of young patients have rim lesions
- A new study found paramagnetic rim lesions, indicating chronic inflammation, in nearly 75% of children with MS.
- More lesions, or PRLs, correlate with faster brain atrophy, suggesting aggressive disease.
- The results, however, show no association between the number of lesions and clinical disability in the young patients in the study.
Children with multiple sclerosis (MS) who have more paramagnetic rim lesions (PRLs) — areas of chronic active inflammation seen on MRI scans — tend to lose more brain volume over time, a new study found.
These lesions were common in pediatric MS, a rare form of the disease that develops during childhood or adolescence, appearing in nearly three-quarters of patients, according to the researchers.
The results suggest that PRL number is linked to more neurodegeneration, but no association was observed between the number of these lesions and clinical disability.
“Taken together, these findings support the hypothesis that PRLs reflect sites of chronic neuroinflammation and may contribute to neurodegeneration over time,” the scientists wrote.
The study, “Paramagnetic Rim Lesions in Pediatric Multiple Sclerosis and Their Association With Brain Tissue Atrophy,” was published in the journal Neurology Neuroimmunology & Neuroinflammation.
MS occurs when the immune system mistakenly attacks myelin, the protective fatty substance covering nerve cells in the brain and spinal cord. These immune attacks damage both the myelin and the nerve cells themselves, and this damage can be seen on MRI scans as lesions, or areas of abnormal tissue.
PRLs are lesions that represent regions of ongoing, chronic inflammation. They are distinguished by the presence of a dark rim of iron-laden immune cells. Such immune cells are gradually contributing to more nerve damage over time.
More brain lesions were not linked to greater disability
While these lesions tend to grow slowly over time, they are associated in adults with a more severe disease course and a faster accumulation of disability. However, few studies have investigated whether PRLs are also associated with worse outcomes in pediatric MS.
To learn more, a group of researchers in the U.K. reviewed the clinical records of 54 children with MS who were treated at four hospitals in the country. Their average age at the first MRI scan was 14, and about three-quarters were girls.
Despite the short disease duration — a median of 7-8 months — most children (74.1%) had at least one PRL visible on MRI, the researchers found. These lesions represented one-quarter of all lesions, and most were found near the brain’s ventricles, which are spaces filled with fluid.
The results showed that children who had more PRLs also had more and larger lesions overall. When the researchers examined brain volume, they found that having more PRLs was significantly associated with smaller volumes of both cortical gray matter and deep gray matter. Cortical gray matter is the brain’s outer layer, responsible for cognition, while deep gray matter is responsible for motor control, among other functions.
Our findings … demonstrate that higher PRL counts correlate with greater inflammatory activity … and more severe brain tissue loss. … [This underlines] their potential role as biomarkers of a more aggressive disease [course].
A total of 45 children had repeated MRI scans over a median follow-up of 17 months, or slightly less than 1.5 years. Although no new lesions appeared and physical disability remained stable, the brain tissue volume continued to decrease among these patients. This reduction was most pronounced in individuals who had a higher number of PRLs at the start of the study, the data showed.
While more PRLs predicted greater loss of deep gray matter volume over time, they were not linked to increased disability — at least not in the short term, the researchers noted. Longer studies are needed to confirm whether PRLs can predict MS disability in children in the long term, as is observed in adults, the team noted.
Key limitations of the study were the small number of children involved and its short duration.
Still, the researchers said that it appears that PRLs are linked to overall lesion burden and faster brain atrophy, “underlining their potential role as biomarkers of a more aggressive disease [course]” for children with MS.
“Our findings … demonstrate that higher PRL counts correlate with greater inflammatory activity … and more severe brain tissue loss,” the team wrote.
About the Author
