Author Of 1 Presentation
P0792 - Cerebrospinal fluid amyloid-β as potential biomarker for cognitive functioning in multiple sclerosis. (ID 1698)
Abstract
Background
Cognitive dysfunction occurs in 40-65% of the people with MS (PwMS), which has been related to grey matter (GM) and thalamic atrophy. Whether biomarkers specific to Alzheimer’s disease (AD, i.e. amyloid beta (Aβ42), total Tau, phosphorylated Tau (ptau-181)) are also involved in cognitive dysfunction in MS is not fully elucidated yet.
Objectives
To identify biomarkers in the cerebrospinal fluid (CSF) that are associated with cognition in MS and determine its relation with brain volume.
Methods
In total 62 PwMS visiting the Second Opinion MS and Cognition Outpatient Clinic (41 females; mean age: 47.10±9.30; mean disease duration: 12.65±9.07) underwent lumbar puncture, brain MRI, neurological (EDSS) and neuropsychological examination (MACFIMS). PwMS were classified as cognitively impaired (CI) with 20% of the cognitive test scores of ≤-1.5 SD compared to normative scores. Aβ42 (pg/ml), total tau (pg/ml), ptau-181 (pg/ml), the ratio of ptau-181:Aβ42 and total proteins (mg/l) were measured using Elecsys immunoassays on the Cobas System. FSL’s SIENAX and FIRST were used to calculate brain volumes (white matter volume, GM volume (GMV), thalamus volume and lesion load). Differences between cognitively preserved (CP) and CI patients were calculated as were correlations between CSF biomarkers and brain volumes.
Results
Demographic and MS-specific characteristics were not different between CP and CI patients. Aβ42 was below the clinical cut-off (<1000pg/ml) in 13/35 CI patients compared to 2/25 CP patients (37% and 8% respectively, P=.013). The chance of being CI was 6.5 times higher if Aβ42 was below this cut-off (odds-ratio; 95% CI [1.3 – 32.3]). On a group level, a trend towards lowered Aβ42 was found in CI compared to CP patients (1264.20±478.63 versus 1490.79±384.37 pg/ml; P=.059), albeit within the normal range. No differences were found for the other CSF markers. CI patients had lower GMV (P=.002) and thalamic volume (P=.011), compared to CP patients. Only in CP patients, thalamus volume correlated with Aβ42 (r=.475, P=.019). No other correlations were found between Aβ42 and brain volumes.
Conclusions
Aβ42 levels below the clinical cut-off was seen more often in CI patients, as were a lower GMV and lower thalamic volume compared to CP patients. Only in CP patients Aβ42 and thalamic volume were correlated, which disappeared in the more advanced disease stage (CI), comparable to findings in mild cognitive impairment and AD. The specificity of Aβ42 pathology in relation to cognition in MS needs further investigation.