‘A comprehensive review’
In a comment, Jeffrey A. Cohen, MD, director of the Cleveland Clinic’s Mellen Center for MS Treatment and Research, said the article is a comprehensive review of the pathologic mechanisms that underlie progression in MS and the proxy measures of those processes (brain and spinal cord MRI, PET, optical coherence tomography, and biomarkers).
“The paper reports there is no qualitative difference between relapsing remitting and progressive MS; rather, the difference is quantitative,” Dr. Cohen noted. “In other words, the processes that underlie progression are present from the earliest stages of MS, becoming more prominent over time.”
The apparent transition to progressive MS, he added, “rather than representing a ‘transition,’ instead results from the accumulation of pathology over time, a shift from focal lesions to diffuse inflammation and damage, and unmasking of the damage due to decreased resiliency due to aging and failure of compensatory mechanisms (neuroplasticity and remyelination).”
Also commenting, Edward Fox, MD, director, MS Clinic of Central Texas and clinical associate professor, University of Texas, Austin, explained that loss of tissue is the main driver of progressive MS.
“We all look at imaging to confirm that the progressive symptoms expressed by the patient are related to demyelinating disease,” he said. “When I see MRI of the spinal cord showing multifocal lesions, especially if localized atrophy is seen in a region of the cord, I expect to hear a history of progressive deficits in gait and other signs of disability.”
Dr. Fox noted that, on MRI of the brain, gray matter atrophy both cortically and in the deep gray structures usually manifests as cognitive slowing and poorer performance in work and social situations.
“We hope that other biomarkers, such as neurofilament light chain, will add to this body of knowledge and give us a better grasp of the definition of neurodegeneration to confirm the clinical and radiographic findings,” he added.
Dr. Filippi has received compensation for consulting services and/or speaking activities from Bayer, Biogen Idec, Merck Serono, Novartis, Roche, Sanofi, Genzyme, Takeda, and Teva Pharmaceutical Industries; and research support from ARiSLA, Biogen Idec, Fondazione Italiana Sclerosi Multipla, Italian Ministry of Health, Merck Serono, Novartis, Roche, and Teva.
A version of this article first appeared on Medscape.com.