Heuer, Hilary W.

AbstractINTRODUCTIONHigher male prevalence in sporadic behavioral variant frontotemporal dementia (bvFTD) has been reported. We hypothesized differences in phenotypes between genetic and sporadic bvFTD females resulting in underdiagnosis of sporadic bvFTD females.METHODSWe included genetic and sporadic bvFTD patients from two multicenter cohorts. We compared behavioral and cognitive symptoms, and gray matter volumes, between genetic and sporadic cases in each sex.RESULTSFemales with sporadic bvFTD showed worse compulsive behavior (p = 0.026) and language impairments (p = 0.024) compared to females with genetic bvFTD (n = 152). Genetic bvFTD females had smaller gray matter volumes than sporadic bvFTD females, particularly in the parietal lobe.DISCUSSIONFemales with sporadic bvFTD exhibit a distinct clinical phenotype compared to females with genetic bvFTD. This difference may explain the discrepancy in prevalence between genetic and sporadic cases, as some females without genetic mutations may be misdiagnosed due to atypical bvFTD symptom presentation.Highlights Sex ratio is equal in genetic behavioral variant of frontotemporal dementia (bvFTD), whereas more males are present in sporadic bvFTD. Distinct neuropsychiatric phenotypes exist between sporadic and genetic bvFTD in females. Phenotype might explain the sex ratio difference between sporadic and genetic cases.

Abstract INTRODUCTION Sex differences are apparent in neurodegenerative diseases but have not been comprehensively characterized in frontotemporal dementia (FTD). METHODS Participants included 337 adults with autosomal dominant FTD enrolled in the ALLFTD Consortium. Clinical assessments and plasma were collected annually for up to 6 years. Linear mixed‐effects models investigated how sex and disease stage are associated with longitudinal trajectories of cognition, function, and neurofilament light chain (NfL). RESULTS While sex differences were not apparent at asymptomatic stages, females showed more rapid declines across all outcomes in symptomatic stages compared to males. In asymptomatic participants, the association between baseline NfL and clinical trajectories was weaker in females versus males, a difference that was not present in symptomatic participants. DISCUSSION In genetic FTD, females show cognitive resilience in early disease stages followed by steeper clinical declines later in the disease. Baseline NfL may be a less sensitive prognostic tool for clinical progression in females with FTD‐causing mutations. Highlights Females with genetic FTD exhibit overall steeper increases in plasma neurofilament light chain (NfL) than males. Females with genetic FTD outperform NfL levels in asymptomatic stages compared to males. Once symptomatic, females with genetic FTD decline more rapidly than males. Plasma NfL is a stronger prognostic marker in asymptomatic males than females.

AbstractINTRODUCTIONPlasma amyloid beta42/amyloid beta40 (Aβ42/Aβ40) and phosphorylated tau217 (p‐tau217) identify individuals with primary Alzheimer's disease (AD). They may detect AD co‐pathology in the setting of other primary neurodegenerative diseases, but this has not been systematically studied.METHODSWe compared the clinical, neuroimaging, and neuropathological associations of plasma Aβ42/Aβ40 (mass spectrometry), p‐tau217 (electrochemiluminescence), and neurofilament light ([NfL], single molecule array [Simoa]), as markers of AD co‐pathology, in a sporadic frontotemporal dementia (FTD) cohort (n = 620).RESULTSAβ42/Aβ40 showed no clinicopathological associations. High p‐tau217 was present in amnestic dementia (AmD) presumed to be due to FTD, logopenic primary progressive aphasia (lvPPA), and APOEε4 carriers, and correlated with worse baseline and longitudinal clinical scores, lower hippocampal volumes, and more severe AD co‐pathology (Braak Stage). NfL was elevated in all FTD phenotypes, and correlated with clinical scores and frontotemporal brain volumes.DISCUSSIONPlasma p‐tau217 has clinical, neuroimaging, and neuropathological correlates in sporadic FTD and may identify FTD cases with AD co‐pathology.Highlights Alzheimer's disease (AD) features could be identified with plasma phosphorylated tau217 (p‐tau217) in frontotemporal lobar degeneration (FTLD). Plasma p‐tau217 is a better discriminator of AD co‐pathology and AD‐associated features in FTLD than plasma amyloid beta42/amyloid beta40 (Aβ42/Aβ40) and neurofilament light (NfL). In FTLD, plasma p‐tau217, but not Aβ42/Aβ40 or neurofilament light, has phenotypical, neurocognitive, and neuroimaging correlates suggestive of AD co‐pathology.

Abstract The largest risk factor for dementia is age. Heterochronic blood exchange studies have uncovered age-related blood factors that demonstrate ‘pro-aging’ or ‘pro-youthful’ effects on the mouse brain. The clinical relevance and combined effects of these factors for humans is unclear. We examined five previously identified brain rejuvenation factors in cerebrospinal fluid of adults with autosomal dominant forms of frontotemporal dementia and sporadic Alzheimer’s disease. Our frontotemporal dementia cohort included 100 observationally followed adults carrying autosomal dominant frontotemporal dementia mutations (Mage = 49.6; 50% female; 43% C9orf72, 24% GRN, 33% MAPT) and 62 non-carriers (Mage = 52.6; 45% female) with cerebrospinal fluid analysed on Somascan, and longitudinal (Mvisits = 3 years, range 1–7 years) neuropsychological and functional assessments and plasma neurofilament light chain. Our Alzheimer’s disease cohort included 35 adults with sporadic Alzheimer’s disease (Mage = 69.4; 60% female) and 56 controls (Mage = 68.8, 50% female) who completed the same cerebrospinal fluid and clinical outcome measures cross-sectionally. Levels of C-C motif chemokine ligand 11, C-C motif chemokine ligand 2, beta-2-micorglobulin, bone gamma-carboxyglutamate protein (aka Osteocalcin) and colony stimulating factor 2 in cerebrospinal fluid were linearly combined into a composite score, with higher values reflecting ‘pro-youthful’ levels. In genetic frontotemporal dementia, higher baseline cerebrospinal fluid rejuvenation proteins predicted slower decline across cognitive, functional, and neurofilament light chain trajectories; estimates were similar across genotypes. In transdiagnostic analyses, higher cerebrospinal fluid rejuvenation proteins associated with better functional, cognitive, and neurofilament light chain outcomes in adults with sporadic Alzheimer’s disease. Proteins with pre-clinical evidence for brain rejuvenation show translational clinical relevance in adults with Alzheimer’s disease and related dementias and warrant further investigation.

AbstractBackgroundSubjective cognitive concerns are common in functionally intact adults, potentially indicating future cognitive decline. Remote smartphone cognitive testing holds promise for objectively tracking cognition in individuals reporting complaints. In our initial exploration of the link between subjective cognitive complaints and digital clinical outcomes, we examined participants' self‐reported cognitive complaints' association with smartphone tests on memory and executive functioning.MethodsParticipants, without self‐reported MCI or dementia, were recruited from the UCSF Brain Healthy Registry (BHR) to complete cognitive tasks on their personal smartphone with the ALLFTD Mobile App. Participants also completed the 12‐item Everyday Cognition Screening Tool (ECog‐12), assessing subjective cognitive impairment, online as part of BHR. Average ECog‐12 scores, including Memory and Executive Functioning subdomains, were calculated. Correlations between scores from online ECog‐12 scores and app‐based smartphone tasks were examined. Regression analyses, adjusting for age, education, and sex, were performed to evaluate the relationship between ECog‐12 and smartphone tasks (Stroop & Flanker) measuring executive function and memory.ResultsOut of 2,283 invited BHR participants, 456 (mean age: 64.6 years (SD=11.8) and education: 16.3 years (SD=2.4)) completed smartphone tasks (81.1% completion rate). Age was negatively associated with executive functioning and memory tasks (β’s=‐0.51 to ‐0.54, p’s<0.05), while higher education correlated with better performance (β’s=0.10‐0.14, p’s<0.05). Sex was not significantly associated with performance on any task (β’s=‐0.04 to 0.09, p’s>0.05). Subjective cognitive concerns were linked to tasks of executive functioning (Stroop: β=‐0.18, p=0.002) and memory (β=‐0.14, p=0.02). Endorsement of executive functioning items on ECog‐12 associated with Stroop performance (β=‐0.16, p=0.005), and memory‐specific complaints were related to memory performance (β=‐0.1, p=0.09). The relationship with flanker scores was not significant (β=‐0.08, p=0.17). Similar patterns emerged with the online ECog‐12; online and app‐based scores are strongly correlated (β=0.75, p<0.05).ConclusionsIn this cognitively intact sample, subjective cognitive concerns were linked to poorer performance on ALLFTD Mobile App tasks assessing executive functioning and memory. These findings suggest that unsupervised remote smartphone testing merits further consideration to monitor cognition in individuals with subjective cognitive concerns. Subsequent studies in deeply phenotyped cohorts with follow‐up assessments are essential for understanding the clinical relevance of these results.

AbstractBackgroundAs new anti‐amyloid immunotherapies emerge for Alzheimer’s disease (AD), it is clear that early diagnosis of AD pathology is crucial for treatment success. This can be challenging in atypical presentations of AD and, together with our reliance on CSF or PET scans, can, at times, lead to delayed diagnosis. Here, we further explore the possible role of plasma tau phosphorylated at threonine 217 (P‐tau217) for the detection of primary AD or AD co‐pathology when frontotemporal dementia spectrum disorders are the main clinical presentation.MethodParticipants were recruited through ALLFTD, a North American multisite research consortium for the longitudinal assessment of frontotemporal lobar degeneration. After excluding cases with known FTD‐causing mutations, 573 participants with sporadic disease, mild cognitive/behavioral impairment, or healthy familial controls evaluated between 2014 and 2023 were included in this analysis (45.8% female, median age 66 years). 39 of those cases underwent neuropathological evaluation. Plasma P‐tau217 was measured with the Eli Lilly electrochemiluminescence‐based assay. P‐tau217 concentrations were compared by phenotype, disease severity, genotype, and, when available, neuropathological diagnosis with non‐parametric tests. Its diagnostic performance was tested with ROC curves. Associations between plasma P‐tau217 concentrations and clinical scales of global cognition, memory, executive function, motor function, and social cognition with linear regressions and non‐parametric tests.ResultPlasma P‐tau217 concentrations were higher in logopenic variant primary progressive aphasia (lvPPA) and amnestic dementia (AmDem), compared to participants with normal cognition or other FTD phenotypes. P‐tau217 concentrations were higher in APOE e4 carriers, compared to non‐carriers, regardless of phenotype, but were not affected by disease severity. P‐tau217 concentrations showed associations with clinical measures of global cognition, memory, and executive function, but had no associations with measures of motor function or social cognition. Plasma P‐tau217 concentrations were elevated in high and intermediate ADNC scoring, or more advanced Braak stages, even when AD was not the primary pathology.ConclusionEven when FTD is suspected, high plasma p‐tau 217 concentrations are strongly associated with underlying AD as primary pathology or contributing co‐pathology. Plasma P‐tau217 could be a tool to support the development of disease‐modifying therapies for atypical Alzheimer’s disease presentations or for FTD cases with Alzheimer’s disease co‐pathology.

AbstractBackgroundGrowth Differentiation Factor 15 (GDF15) is a TGF‐beta superfamily protein upregulated during immune‐mediated stress responses. Peripheral GDF15 is linked to adverse aging across organ systems including the brain. Immune dysregulation is implicated in frontotemporal dementia (FTD) pathogenesis. We examined how plasma GDF15 levels associated with longitudinal cognitive and neurofilament light chain (NfL) trajectories in adults with FTD and controls. Furthermore, we tested the utility of GDF15 as a prognostic biomarker against common inflammatory proteins (CRP and IL6).Method231 adults with FTD (24.35% sporadic FTD syndromes; 19.19% MAPT; 19.56% GRN; 22.14% C9orf72 pathogenic carriers) and 40 normal controls from the ALLFTD Consortium completed longitudinal neuropsychological testing and a blood draw with plasma analyzed on SomaScan V4.0 (baseline only: GDF15, CRP, and IL6) and Simoa (longitudinal: NfL). CRP and IL6 were selected as control markers to test the specificity of GDF15. Linear mixed effects models separately examined longitudinal cognition (global, executive functioning, memory, and language z‐scores) and plasma NfL levels as a function of baseline plasma GDF15, time, and their interaction, controlling for baseline age, sex, and education. Parallel models were conducted for CRP and IL6.ResultIn the whole cohort, higher baseline plasma GDF15 levels associated with steeper global cognitive decline (b = ‐3.91, p = 0.0092) and NfL accumulation (b = 3.88, p = 0.00088) over time. When examining cognitive domains, we found GDF15 only associated with worse executive functioning trajectories (b = ‐3.19, p = 0.0021). In contrast, baseline levels of CRP and IL6 did not display statistically significant relationships with cognitive or NfL trajectories. Prognostic effects of GDF15 remained statistically significant when restricting analyses to those with FTD pathogenic variants (b = ‐2.98, p = 0.0054 [global cognition], b = 2.69, p = 0.0098 [NfL]).ConclusionAdults with FTD and higher baseline peripheral GDF15 levels exhibit accelerated cognitive decline and neurodegeneration. Our results support GDF15 as a potential prognosticator of adverse clinical outcomes in FTD and highlight the relevance of GDF15‐specific pathways in FTD progression. Plasma GDF15 may provide utility over commonly examined inflammatory proteins and further work to explore its clinical value is indicated.

AbstractBackgroundAccumulating evidence indicates that biological sex may influence clinical manifestation within the spectrum of frontotemporal lobar degeneration (FTLD), implying differences in cognitive reserve. Nonetheless, investigations into the impact of biological sex during the preclinical and minimally symptomatic stages of FTLD are lacking.MethodWe included 275 mutation carriers (158 females; 127 with C9orf72, 68 with GRN, and 80 with MAPT mutations) and 161 non‐carrier familial controls (97 females) from the ALLFTD Consortium (Staffaroni et al., Nat Medicine 2022). Participants underwent magnetic resonance imaging (MRI; 348 baseline, 338 longitudinal) and neuropsychological evaluations (394 baseline, 507 longitudinal). Behavioral symptoms were characterized with the Revised Self‐Monitoring Scale (RSMS) and the Neuropsychiatric Inventory (NPI severity scores). MRI‐derived regional volume estimates (RVE) were computed. Cognitive measures and RVE were normalized against sex‐matched controls. Cognitive composites (language, executive function, and visuospatial function) were calculated by averaging raw scores for each domain. Clinical characteristics and RVE comparisons were made between male and female participants. We adopted the residuals approach to explore behavioral and cognitive reserve by fitting a linear regression model for executive z‐scores as the response value and age, education, and RVE as explanatory variables.ResultIn mutation carriers, sex was not a significant differentiator in age, education level, disease severity, or mutation frequency. Most mutation carriers (188, 68%) were asymptomatic or mildly symptomatic at baseline. However, female mutation carriers exhibited significantly lower visuospatial performance at baseline (Cohen's d = ‐0.34, 95% CI[‐0.58, ‐0.09], p=.001). This difference remained significant among asymptomatic GRN mutation carriers (Cohen’s d = ‐0.73, 95% CI[‐1.22, ‐0.23], p=0.003) but not in other mutations. Following the residuals approach, female mutation carriers showed higher executive performance than males for the same amount of both frontotemporal and global atrophy as quantified by RVE (Cohen's d=0.45, 95 % CI[0.22, 0.67], p<.001). The observed higher executive reserve in women was particularly pronounced in C9orf72 carriers (Cohen's d=0.77, 95% CI[0.35, 1.20], p<.001) but not significant in GRN (p=0.48) and MAPT carriers (p=0.07). No differences in behavioral reserve reached statistical significance.ConclusionFemale sex might modulate early cognitive performance and confer higher executive reserve in FTLD mutation carriers.