New research from the Buffalo Neuroimaging Analysis Center (BNAC) at the University at Buffalo indicates that paramagnetic rim lesions (PRLs) could be a more reliable predictor of multiple sclerosis (MS) progression than white matter lesion volume, the traditional marker.
Longitudinal Studies on PRLs
Two longitudinal studies, conducted over five- and 10-year periods, examined the evolution of PRLs in MS patients. The findings, published in Annals of Clinical and Translational Neurology and Neurology, suggest that these lesions, indicative of activated brain immune cells (microglia), are closely linked to MS disease progression.
Robert Zivadinov, professor of neurology and director of BNAC at the Jacobs School of Medicine and Biomedical Sciences at UB, emphasized the motivation behind the research: "Existing multiple sclerosis imaging markers, such as overall white matter lesion volume, poorly predict future MS disease progression. However, much is still unknown regarding the long-term evolution of PRLs and their relationship with disease progression."
Impact of Disease-Modifying Treatments and Lifestyle Factors
The study in Annals of Clinical and Translational Neurology, involving 152 MS patients, revealed that disease-modifying treatments were associated with lower odds of PRL appearance. However, the treatments did not guarantee complete disappearance of existing PRLs. Current smokers, known to be at higher risk for MS progression, showed a higher prevalence of PRLs.
Jack Reeves, MD/PhD candidate and first author of both papers, cautioned that the utility of PRL disappearance or new PRL appearance as outcome measures in clinical trials is somewhat limited without a larger participant pool to determine how moderate-efficacy drugs affect PRLs.
PRL Evolution and Clinical Outcomes
The Neurology study, which included 160 MS patients and 27 healthy controls, found that higher PRL disappearance rates correlated with reduced rates of confirmed disability progression. These results underscore the importance of PRL resolution and the absence of new PRLs for improved clinical outcomes.
Therapeutic Implications
Zivadinov noted, "These findings further motivate the need for novel therapies targeting microglia-mediated brain inflammation and adoption of clinical strategies to prevent appearance of new PRLs." The research indicates that high-efficacy disease-modifying treatments, known for reducing relapses and slowing disease progression, were associated with reduced PRL appearance. This suggests that PRLs could help stratify MS patients into high- and low-risk groups, potentially guiding the selection of disease-modifying therapies.
Future Research Directions
Zivadinov added that future studies should examine PRL evolution at more regular intervals, such as annually, to better understand the trajectory of PRLs in serial imaging studies. BNAC is currently working on additional studies leveraging its extensive longitudinal database of PRLs.
