Low CSF β-amyloid levels predict early regional grey matter atrophy in multiple sclerosis

Biomarkers of tau phosphorylation state are associated with the clinical course of multiple sclerosis

BACKGROUND

Mechanisms underlying neurodegeneration in multiple sclerosis (MS) remain poorly understood but mostly implicate molecular pathways that are not unique to MS. Recently detected tau seeding activity in MS brain tissues corroborates previous neuropathological reports of hyperphosphorylated tau (p-tau) accumulation in secondary and primary progressive MS (PPMS). We aimed to investigate whether aberrant tau phosphorylation can be detected in the cerebrospinal fluid (CSF) of MS patients by using novel ultrasensitive immunoassays for different p-tau biomarkers.

METHODS

CSF samples of patients with MS (n = 55) and non-inflammatory neurological disorders (NIND, n = 31) were analysed with in-house Single molecule array (Simoa) assays targeting different tau phosphorylation sites (p-tau181, p-tau212, p-tau217 and p-tau231). Additionally, neurofilament light (NFL) and glial fibrillary acidic protein (GFAP) were measured with a multiplexed Simoa assay. Patients were diagnosed with clinically isolated syndrome (CIS, n = 10), relapsing-remitting MS (RRMS, n = 21) and PPMS (n = 24) according to the 2017 McDonald criteria and had MRI, EDSS and basic CSF analysis performed at the time of diagnosis.

RESULTS

Patients with progressive disease course had between 1.4-fold (p-tau217) and 2.2-fold (p-tau212) higher p-tau levels than relapsing MS patients (PPMS compared with CIS + RRMS, p < 0.001 for p-tau181, p-tau212, p-tau231 and p = 0.042 for p-tau217). P-tau biomarkers were associated with disease duration (ρ=0.466-0.622, p < 0.0001), age (ρ=0.318-0.485, p < 0.02, all but p-tau217) and EDSS at diagnosis and follow-up (ρ=0.309-0.440, p < 0.02). In addition, p-tau biomarkers correlated with GFAP (ρ=0.517-0.719, p ≤ 0.0001) but not with the albumin quotient, CSF cell count or NFL. Patients with higher MRI lesion load also had higher p-tau levels p ≤ 0.01 (<10 vs. ≥ 10 lesions, all p ≤ 0.01).

CONCLUSION

CSF concentrations of novel p-tau biomarkers point to a higher degree of tau phosphorylation in PPMS than in RRMS. Associations with age, disease duration and EDSS suggest this process increases with disease severity; however, replication of these results in larger cohorts is needed to further clarify the relevance of altered tau phosphorylation throughout the disease course in MS.

Patterns of brain atrophy in recently-diagnosed relapsing-remitting multiple sclerosis

Recurrent neuroinflammation in relapsing-remitting MS (RRMS) is thought to lead to neurodegeneration, resulting in progressive disability. Repeated magnetic resonance imaging (MRI) of the brain provides non-invasive measures of atrophy over time, a key marker of neurodegeneration. This study investigates regional neurodegeneration of the brain in recently-diagnosed RRMS using volumetry and voxel-based morphometry (VBM). RRMS patients (N = 354) underwent 3T structural MRI <6 months after diagnosis and 1-year follow-up, as part of the Scottish multicentre 'FutureMS' study. MRI data were processed using FreeSurfer to derive volumetrics, and FSL for VBM (grey matter (GM) only), to establish regional patterns of change in GM and normal-appearing white matter (NAWM) over time throughout the brain. Volumetric analyses showed a decrease over time (q<0.05) in bilateral cortical GM and NAWM, cerebellar GM, brainstem, amygdala, basal ganglia, hippocampus, accumbens, thalamus and ventral diencephalon. Additionally, NAWM and GM volume decreased respectively in the following cortical regions, frontal: 14 out of 26 regions and 16/26; temporal: 18/18 and 15/18; parietal: 14/14 and 11/14; occipital: 7/8 and 8/8. Left GM and NAWM asymmetry was observed in the frontal lobe. GM VBM analysis showed three major clusters of decrease over time: 1) temporal and subcortical areas, 2) cerebellum, 3) anterior cingulum and supplementary motor cortex; and four smaller clusters within the occipital lobe. Widespread GM and NAWM atrophy was observed in this large recently-diagnosed RRMS cohort, particularly in the brainstem, cerebellar GM, and subcortical and occipital-temporal regions; indicative of neurodegeneration across tissue types, and in accord with limited previous studies in early disease. Volumetric and VBM results emphasise different features of longitudinal lobar and loco-regional change, however identify consistent atrophy patterns across individuals. Atrophy measures targeted to specific brain regions may provide improved markers of neurodegeneration, and potential future imaging stratifiers and endpoints for clinical decision making and therapeutic trials.

BACE1 influences clinical manifestations and central inflammation in relapsing remitting multiple sclerosis

Neurodegenerative and inflammatory processes influence the clinical course of multiple sclerosis (MS). The β-site amyloid precursor protein cleaving enzyme 1 (BACE1) has been associated with cognitive dysfunction, amyloid deposition and neuroinflammation in Alzheimer's disease. We explored in a group of 50 patients with relapsing-remitting MS the association between the cerebrospinal fluid (CSF) levels of BACE1, clinical characteristics at the time of diagnosis and prospective disability after three-years follow-up. In addition, we assessed the correlations between the CSF levels of BACE 1, amyloid β (Aβ) 1-40 and 1-42, phosphorylated tau (pTau), lactate, and a set of inflammatory and anti-inflammatory molecules. BACE1 CSF levels were correlated positively with depression as measured with Beck Depression Inventory-Second Edition scale, and negatively with visuospatial memory performance evaluated by the Brief Visuospatial Memory Test-Revised. In addition, BACE CSF levels were positively correlated with Bayesian Risk Estimate for MS at onset, and with Expanded Disability Status Scale score assessed three years after diagnosis. Furthermore, a positive correlation was found between BACE1, amyloid β 42/40 ratio (Spearman's r = 0.334, p = 0.018, n = 50), pTau (Spearman's r = 0.304, p = 0.032, n = 50) and lactate concentrations (Spearman's r = 0.361, p = 0.01, n = 50). Finally, an association emerged between BACE1 CSF levels and a group of pro and anti-inflammatory molecules, including interleukin (IL)-4, IL-17, IL-13, IL-9 and interferon-γ. BACE1 may have a role in different key mechanisms such as neurodegeneration, oxidative stress and inflammation, influencing mood, cognitive disorders and disability progression in MS.

Resveratrol targeting tau proteins, amyloid-beta aggregations, and their adverse effects: An updated review

Resveratrol (Res) is a non-flavonoid compound with pharmacological actions such as antioxidant, antiinflammatory, hepatoprotective, antidiabetes, and antitumor. This plant-derived chemical has a long history usage in treatment of diseases. The excellent therapeutic impacts of Res and its capability in penetration into blood-brain barrier have made it an appropriate candidate in the treatment of neurological disorders (NDs). Tau protein aggregations and amyloid-beta (Aβ) deposits are responsible for the induction of NDs. A variety of studies have elucidated the role of these aggregations in NDs and the underlying molecular pathways in their development. In the present review, based on the recently published articles, we describe that how Res administration could inhibit amyloidogenic pathway and stimulate processes such as autophagy to degrade Aβ aggregations. Besides, we demonstrate that Res supplementation is beneficial in dephosphorylation of tau proteins and suppressing their aggregations. Then, we discuss molecular pathways and relate them to the treatment of NDs.