News & Views

A new study, drawing on data from national biobanks, adds to the growing evidence that exposure to common viral pathogens increases the risk of Alzheimer disease and other neurodegenerative diseases. These findings might provide insights into the initiating factors that lead to neurodegeneration.

Findings from a worldwide cohort of cognitively unimpaired individuals demonstrate that the presence of two canonical Alzheimer disease biomarkers — amyloid and tau — can reliably predict progression to mild cognitive impairment in the short-term. The results support the use of these biomarkers to diagnose preclinical Alzheimer disease in a clinical setting.

The phase III Clarity AD clinical trial of lecanemab, an amyloid-targeting antibody, showed a small clinical benefit in people with Alzheimer disease. However, several questions remain regarding the true clinical relevance, safety and accessibility of lecanemab in this patient population.

The results of the first randomized, placebo-controlled trial of dimethyl fumarate in a cohort of participants with radiologically isolated syndrome showed efficacy against the risk of a first clinical demyelinating event. The findings pave the way for preventive medicine in multiple sclerosis and highlight the need for more precise prognostication of risk.

Technological advances over the past decade have made precision genetic diagnosis available to many patients. The findings of a new study demonstrate that genetic diagnosis in epilepsy can lead to changes in clinical management that manifest as positive outcomes for the patient. The results herald a new era in which precision diagnosis will lead to precision medicine.

Gene therapies show promise for treating epilepsy, but most strategies target cells across an entire brain region rather than selecting pathologically hyperexcited neurons. Researchers have now developed a conditional gene therapy strategy that downregulates firing activity only in neurons that are pathologically overactive and switches off when brain circuit activity has returned to baseline.

A new study provides evidence for an association between COVID-19 and long-term neurological syndromes. The findings highlight the need for further research into the long-term neurological consequences of SARS-CoV-2 infection and the development of strategies that lessen the effects of these consequences on patient quality of life and on healthcare systems.

In a study of 17,000 Medicare beneficiaries with mild cognitive impairment or dementia, non-Hispanic white older adults were more likely than Asian, Black or Hispanic older adults to have elevated cortical amyloid, as measured by PET. These findings have important implications for the use of amyloid-targeting therapies.

Genome-wide association studies have identified loci associated with neurodegenerative disease risk, but many of the implicated genetic variants are noncoding and their functional roles remain unclear. Using massively parallel reporter assays, CRISPR-based validation and genomic annotations, a new study functionally characterizes regulatory risk variants associated with Alzheimer disease and progressive supranuclear palsy.

In the first two phase II trials of therapies that target α-synuclein to treat Parkinson disease, the primary endpoints were not met. However, the limitations of these studies need to be addressed in future trials and alternative approaches to targeting α-synuclein should be pursued before α-synuclein is discounted as a target.

Currently, the anti-CD20 monoclonal antibody ocrelizumab is the only approved treatment for primary progressive multiple sclerosis (PPMS). However, a new study suggests that other immunomodulatory disease-modifying therapies that are often used to treat relapsing forms of multiple sclerosis could be effective in people with PPMS who have evidence of active inflammatory disease.

New work building on the results of genome-wide association studies in Alzheimer disease has identified molecular mechanisms that are shared with some psychiatric disorders. The study leveraged ‘omics data and has the realistic potential to elucidate unknown disease mechanisms; however, a lack of information about neuropsychiatric symptoms in the participants with Alzheimer disease limits the conclusions.

A phase II trial of the tau antibody semorinemab indicates that it has no clinical benefit in the earliest stages of Alzheimer disease. The repeated finding that antibody-mediated reductions in protein pathology have limited or no clinical benefit indicates that we need to consider more specific or combined therapeutic targets.

Cognitive rehabilitation is a promising approach to limit the effect of cognitive impairment on patients with multiple sclerosis, although results so far are conflicting. A new study indicates that structural and functional MRI techniques could provide reliable measures to predict treatment responses and tailor the rehabilitative approach to each patient.

A new longitudinal study involving carriers of amyotrophic lateral sclerosis (ALS)-associated mutations has identified a prodromal phase of ALS characterized by mild motor impairment. The findings could help us to define a time window during which neuroprotective interventions might be effective in patients with genetic forms of ALS.

A new genome-wide association study has identified 41 previously unknown loci associated with Alzheimer disease. However, these data provide limited insight into disease mechanisms or benefits for clinical prediction of Alzheimer disease.

A new paper published in Neuron presents an analysis of mRNA expression in human and mouse trigeminal ganglia at single-nucleus resolution. The resulting resource is thought-provoking and suggests new targets for pain therapies; however, the findings should be interpreted in the context of the available protein data and warrant functional verification.

Analysis of brain images taken before and after infection with SARS-CoV-2 suggests that even mild COVID-19 is associated with brain structure alterations and cognitive impairment. However, the clinical implications for individuals are unclear and further studies are needed to assess the generalizability of the findings and whether the effects are long-lasting.

A recent publication reveals progressive, dose-dependent ventricular enlargement in the brains of patients with early Alzheimer disease who were treated with the FDA-approved drug aducanumab. Aducanumab joins a growing list of anti-amyloid-β therapies for which there is evidence that they cause accelerated neurodegeneration; extended follow-up studies are required to determine whether aducanumab causes progressive brain damage.

The mechanistic contribution of cerebrovascular dysfunction to neurodegenerative diseases is difficult to determine. New single-cell transcriptomic analyses of human brain microvessels have identified transcriptomic signatures along the arteriovenous axis and transcriptional changes in the cerebrovasculature in Alzheimer disease and Huntington disease. This approach could advance our understanding of brain health and disease.