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Supplemental material, sj-pdf-1-jcb-10.1177_0271678X231152001 for Amyloid-PET of the white matter: Relationship to free water, fiber integrity, and cognition in patients with dementia and small vessel disease by Julie Ottoy, Miracle Ozzoude, Katherine Zukotynski, Min Su Kang, Sabrina Adamo, Christopher Scott, Joel Ramirez, Walter Swardfager, Benjamin Lam, Aparna Bhan, Parisa Mojiri, Alex Kiss, Stephen Strother, Christian Bocti, Michael Borrie, Howard Chertkow, Richard Frayne, Robin Hsiung, Robert Jr Laforce, Michael D Noseworthy, Frank S Prato, Demetrios J Sahlas, Eric E Smith, Phillip H Kuo, Jordan A Chad, Ofer Pasternak, Vesna Sossi, Alexander Thiel, Jean-Paul Soucy, Jean-Claude Tardif, Sandra E Black, Maged Goubran in Journal of Cerebral Blood Flow & Metabolism

ObjectiveA GGGGCC repeat expansion in the C9orf72 gene is the most common cause of genetic frontotemporal dementia (FTD) and amyotrophic lateral sclerosis (ALS). As potential therapies targeting the repeat expansion are now entering clinical trials, sensitive biomarker assays of target engagement are urgently required. Our objective was to develop such an assay.MethodsWe used the single molecule array (Simoa) platform to develop an immunoassay for measuring poly(GP) dipeptide repeat proteins (DPRs) generated by the C9orf72 repeat expansion in cerebrospinal fluid (CSF) of people with C9orf72-associated FTD/ALS.Results and conclusionsWe show the assay to be highly sensitive and robust, passing extensive qualification criteria including low intraplate and interplate variability, a high precision and accuracy in measuring both calibrators and samples, dilutional parallelism, tolerance to sample and standard freeze–thaw and no haemoglobin interference. We used this assay to measure poly(GP) in CSF samples collected through the Genetic FTD Initiative (N=40 C9orf72 and 15 controls). We found it had 100% specificity and 100% sensitivity and a large window for detecting target engagement, as the C9orf72 CSF sample with the lowest poly(GP) signal had eightfold higher signal than controls and on average values from C9orf72 samples were 38-fold higher than controls, which all fell below the lower limit of quantification of the assay. These data indicate that a Simoa-based poly(GP) DPR assay is suitable for use in clinical trials to determine target engagement of therapeutics aimed at reducing C9orf72 repeat-containing transcripts., publishedVersion

Key Points Question Is intensive blood pressure reduction associated with lower rates of cognitive decline and dementia? Findings In this systematic review and meta-analysis of 5 randomized clinical trials with 17 396 participants, there was no significant association of lower blood pressure targets vs standard blood pressure management with the incidence of cognitive decline, dementia, and mild cognitive impairment in middle-aged and older adults with hypertension. Meaning These findings suggest that current evidence does not support intensive blood pressure reduction as a preventive strategy for cognitive decline and dementia., This systematic review and meta-analysis explores the association of intensive blood pressure reduction vs standard blood pressure management with the incidence of cognitive decline and dementia in adults with hypertension., Importance Optimal blood pressure (BP) targets for the prevention of cognitive impairment remain uncertain. Objective To explore the association of intensive (ie, lower than usual) BP reduction vs standard BP management with the incidence of cognitive decline and dementia in adults with hypertension. Data Sources and Study Selection A systematic review and meta-analysis of randomized clinical trials that evaluated the association of intensive systolic BP lowering on cognitive outcomes by searching MEDLINE, Embase, CENTRAL, Web of Science, CINAHL, PsycINFO, the International Clinical Trials Registry Platform, and ClinicalTrials.gov from database inception to October 27, 2020. Data Extraction and Synthesis Data screening and extraction were performed independently by 2 reviewers based on Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines. The risk of bias was assessed using the Cochrane risk of bias 2 tool. Random-effects models with the inverse variance method were used for pooled analyses. The presence of potential heterogeneity was evaluated with the I2 index. Main Outcomes and Measures The primary outcome was cognitive decline. Secondary outcomes included the incidence of dementia, mild cognitive impairment (MCI), cerebrovascular events, serious adverse events, and all-cause mortality. Results From 7755 citations, we identified 16 publications from 5 trials with 17 396 participants (mean age, 65.7 years [range, 63.0-80.5 years]; 10 562 [60.5%] men) and 2 additional ongoing trials. All 5 concluded trials included in quantitative analyses were considered at unclear to high risk of bias. The mean follow-up duration was 3.3 years (range, 2.0 to 4.7 years). Intensive BP reduction was not significantly associated with global cognitive performance (standardized mean difference, 0.01; 95% CI, −0.04 to 0.06; I2 = 0%; 4 trials; 5246 patients), incidence of dementia (risk ratio [RR], 1.09; 95% CI, 0.32 to 3.67; I2 = 27%; 2 trials; 9444 patients) or incidence of MCI (RR, 0.91; 95% CI, 0.73 to 1.14; I2 = 74%; 2 trials; 10 774 patients) when compared with standard treatment. However, a reduction of cerebrovascular events in the intensive group was found (RR, 0.79; 95% CI, 0.67 to 0.93; I2 = 0%; 5 trials; 17 396 patients) without an increased risk of serious adverse events or mortality. Conclusions and Relevance In this study, there was no significant association between BP reduction and lower risk of cognitive decline, dementia, or MCI. The certainty of this evidence was rated low because of the limited sample size, the risk of bias of included trials, and the observed statistical heterogeneity. Therefore, current available evidence does not justify the use of lower BP targets for the prevention of cognitive decline and dementia.

ObjectiveCognitively engaging lifestyles have been associated with reduced risk of conversion to dementia. Multiple mechanisms have been advocated, including increased brain volumes (ie, brain reserve) and reduced disease progression (ie, brain maintenance). In cross-sectional studies of presymptomatic frontotemporal dementia (FTD), higher education has been related to increased grey matter volume. Here, we examine the effect of education on grey matter loss over time.MethodsTwo-hundred twenty-nine subjects at-risk of carrying a pathogenic mutation leading to FTD underwent longitudinal cognitive assessment and T1-weighted MRI at baseline and at 1 year follow-up. The first principal component score of the graph-Laplacian Principal Component Analysis on 112 grey matter region-of-interest volumes was used to summarise the grey matter volume (GMV). The effects of education on cognitive performances and GMV at baseline and on the change between 1 year follow-up and baseline (slope) were tested by Structural Equation Modelling.ResultsHighly educated at-risk subjects had better cognition and higher grey matter volume at baseline; moreover, higher educational attainment was associated with slower loss of grey matter over time in mutation carriers.ConclusionsThis longitudinal study demonstrates that even in presence of ongoing pathological processes, education may facilitate both brain reserve and brain maintenance in the presymptomatic phase of genetic FTD.