BACKGROUND: Spatial navigation deficits are early symptoms of Alzheimer's disease (AD). The apolipoprotein E (APOE) ε4 allele is the most important genetic risk factor for AD. This study investigated effects of APOE genotype on spatial navigation in biomarker-defined individuals with amnestic mild cognitive impairment (aMCI) and associations of AD biomarkers and atrophy of AD-related brain regions with spatial navigation. METHODS: 107 participants, cognitively normal older adults (CN, n = 48) and aMCI individuals stratified into AD aMCI (n = 28) and non-AD aMCI (n = 31) groups, underwent cognitive assessment, brain MRI, and spatial navigation assessment using the Virtual Supermarket Test with egocentric and allocentric tasks and a self-report questionnaire. Cerebrospinal fluid (CSF) biomarkers (amyloid-β1-42, phosphorylated tau181 and total tau) and amyloid PET imaging were assessed in aMCI participants. RESULTS: AD aMCI participants had the highest prevalence of APOE ε4 carriers and worst allocentric navigation. CSF levels of AD biomarkers and atrophy in AD-related brain regions were associated with worse allocentric navigation. Between-group differences in spatial navigation and associations with AD biomarkers and regional brain atrophy were not influenced by APOE genotype. Self-reported navigation ability was similar across groups and unrelated to spatial navigation performance. CONCLUSIONS: These findings suggest that allocentric navigation deficits in aMCI individuals are predominantly driven by AD pathology, independent of APOE genotype. This highlights the role of AD pathology as measured by biomarkers, rather than genetic status, as a major factor in navigational impairment in aMCI, and emphasizes the assessment of spatial navigation as a valuable tool for early detection of AD.

• Klíčová slova
• Allocentric navigation, Amyloid-β, Egocentric navigation, Entorhinal cortex, Hippocampus, Tau protein,
• MeSH
• Alzheimerova nemoc * genetika   mozkomíšní mok   diagnostické zobrazování   komplikace   patofyziologie   patologie   MeSH
• amyloidní beta-protein mozkomíšní mok   MeSH
• apolipoprotein E4 * genetika   MeSH
• apolipoproteiny E * genetika   MeSH
• atrofie MeSH
• biologické markery mozkomíšní mok   MeSH
• genotyp MeSH
• kognitivní dysfunkce * genetika   mozkomíšní mok   diagnostické zobrazování   patofyziologie   MeSH
• lidé středního věku MeSH
• lidé MeSH
• magnetická rezonanční tomografie MeSH
• mozek patologie   diagnostické zobrazování   MeSH
• neuropsychologické testy MeSH
• peptidové fragmenty mozkomíšní mok   MeSH
• pozitronová emisní tomografie MeSH
• prostorová navigace * fyziologie   MeSH
• proteiny tau mozkomíšní mok   MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• Check Tag
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• amyloid beta-protein (1-42) MeSH Prohlížeč
• amyloidní beta-protein MeSH
• apolipoprotein E4 * MeSH
• apolipoproteiny E * MeSH
• biologické markery MeSH
• peptidové fragmenty MeSH
• proteiny tau MeSH

Impaired spatial navigation is early marker of Alzheimer's disease (AD). We examined ability of self- and informant-reported navigation questionnaires to discriminate between clinically and biomarker-defined participants, and associations of questionnaires with navigation performance, regional brain atrophy, AD biomarkers, and biomarker status. 262 participants (cognitively normal, with subjective cognitive decline, amnestic mild cognitive impairment [aMCI], and mild dementia) and their informants completed three navigation questionnaires. Navigation performance, magnetic resonance imaging volume/thickness of AD-related brain regions, and AD biomarkers were measured. Informant-reported questionnaires distinguished between cognitively normal and impaired participants, and amyloid-β positive and negative aMCI. Lower scores were associated with worse navigation performance, greater atrophy in AD-related brain regions, and amyloid-β status. Self-reported questionnaire scores did not distinguish between the groups and were weakly associated with navigation performance. Other associations were not significant. Informant-reported navigation questionnaires may be a screening tool for early AD reflecting atrophy of AD-related brain regions and AD pathology.

• Klíčová slova
• Clinical neuroscience, Disease, Neuroscience,
• Publikační typ
• časopisecké články MeSH

Plasminogen activator inhibitor-1 (PAI-1) impedes brain plasmin synthesis. Reduced plasmin activity facilitates cumulation of amyloid beta (Aβ) in Alzheimer's disease (AD). Since plasmin also regulates the synaptic activity, it is possible that altered PAI-1 is present in other neurodegenerative disorders. We investigated whether PAI-1 and its counter-regulatory tissue plasminogen activator (tPA) are altered in serum of patients with dementia due to frontotemporal lobar degeneration (FTLD). Thirty five FTLD patients (21 in mild cognitive impairment stage (MCI) and 14 in dementia stage) and 10 cognitively healthy controls were recruited. Serum tPA and PAI-1 protein levels were measured by anova. Correlation between biochemical and demographic data were explored by measuring Pearson correlation coefficient. Serum PAI-1 levels were elevated in the FTLD dementia group as compared to FTLD MCI and controls. tPA serum levels and PAI-1/tPA ratio did not significantly differ among groups. There was a negative correlation between PAI-1 serum levels and disease severity measured by MMSE score. No correlations of tPA serum levels and PAI-1/tPA ratio with MMSE were found. Increased PAI-1 serum levels may serve as a marker of dementia in FTLD, suggesting that, besides Aβ pathway, the plasmin system may affect cognition through synaptic activity.

• Klíčová slova
• dementia, frontotemporal lobar degeneration, plasminogen activator inhibitor‐1, tissue‐type plasminogen activator,
• MeSH
• biologické markery krev   MeSH
• frontotemporální lobární degenerace * krev   MeSH
• inhibitor aktivátoru plazminogenu 1 * krev   MeSH
• kognitivní dysfunkce krev   MeSH
• lidé středního věku MeSH
• lidé MeSH
• senioři MeSH
• studie případů a kontrol MeSH
• tkáňový aktivátor plazminogenu krev   metabolismus   MeSH
• Check Tag
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• biologické markery MeSH
• inhibitor aktivátoru plazminogenu 1 * MeSH
• SERPINE1 protein, human MeSH Prohlížeč
• tkáňový aktivátor plazminogenu MeSH

BACKGROUND: Spatial navigation impairment is a promising cognitive marker of Alzheimer's disease (AD) that can reflect the underlying pathology. OBJECTIVES: We assessed spatial navigation performance in AD biomarker positive older adults with amnestic mild cognitive impairment (AD aMCI) vs. those AD biomarker negative (non-AD aMCI), and examined associations between navigation performance, MRI measures of brain atrophy, and cerebrospinal fluid (CSF) biomarkers. METHODS: A total of 122 participants with AD aMCI (n = 33), non-AD aMCI (n = 31), mild AD dementia (n = 28), and 30 cognitively normal older adults (CN) underwent cognitive assessment, brain MRI (n = 100 had high-quality images for volumetric analysis) and three virtual navigation tasks focused on route learning (body-centered navigation), wayfinding (world-centered navigation) and perspective taking/wayfinding. Cognitively impaired participants underwent CSF biomarker assessment [amyloid-β1-42, total tau, and phosphorylated tau181 (p-tau181)] and amyloid PET imaging (n = 47 and n = 45, respectively), with a subset having both (n = 19). RESULTS: In route learning, AD aMCI performed worse than non-AD aMCI (p < 0.001), who performed similarly to CN. In wayfinding, aMCI participants performed worse than CN (both p ≤ 0.009) and AD aMCI performed worse than non-AD aMCI in the second task session (p = 0.032). In perspective taking/wayfinding, aMCI participants performed worse than CN (both p ≤ 0.001). AD aMCI and non-AD aMCI did not differ in conventional cognitive tests. Route learning was associated with parietal thickness and amyloid-β1-42, wayfinding was associated with posterior medial temporal lobe (MTL) volume and p-tau181 and perspective taking/wayfinding was correlated with MRI measures of several brain regions and all CSF biomarkers. CONCLUSION: AD biomarker positive and negative older adults with aMCI had different profiles of spatial navigation deficits that were associated with posterior MTL and parietal atrophy and reflected AD pathology.

• Klíčová slova
• allocentric navigation, egocentric navigation, entorhinal cortex, hippocampus, neurodegeneration, precuneus, retrosplenial cortex, tauopathies,
• Publikační typ
• časopisecké články MeSH