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Background: Cerebral microbleeds (CMB) play an important role in neurodegenerative pathology. Objective: The present study aims to test whether cerebrospinal fluid (CSF) growth-associated protein 43 (GAP-43) level is linked to CMBs in elderly people. Methods: A total of 750 participants from the Alzheimer's Disease Neuroimaging Initiative (ADNI) who had measurements of GAP-43 and CMBs were included in the study. According to the presence and extent of CMBs, participants were stratified into different groups. Regression analyses were used to assess cross-sectional and longitudinal associations between GAP-43 and CMBs. Results: Participants with CMB were slightly older and had higher concentrations of CSF GAP43. In multivariable adjusted analyses for age, gender, APOEɛ4 status, and cognitive diagnoses, higher CSF GAP-43 concentrations were modestly associated with CMB presence (OR = 1.169, 95% CI = 1.001–1.365) and number (β= 0.020, SE = 0.009, p = 0.027). Similarly, higher CSF GAP43 concentrations were accrual of CMB lesions, associated with higher CMB progression (OR = 1.231, 95% CI = 1.044–1.448) and number (β= 0.017, SE = 0.005, p = 0.001) in the follow up scan. In stratified analyses, slightly stronger associations were noted in male participants, those 65 years and older, carriers of APOEɛ4 alleles, and with more advanced cognitive disorders. Conclusions: CSF GAP-43 was cross-sectionally associated with the presence and extent of CMBs. GAP-43 might be used as a biomarker to track the dynamic changes of CMBs in elderly persons. [ABSTRACT FROM AUTHOR]

High dietary intake of saturated fatty acids is a suspected risk factor for neurodegenerative diseases, including Alzheimer's disease (AD). To decipher the causal link behind these associations, high-fat diets (HFD) have been repeatedly investigated in animal models. Preclinical studies allow full control over dietary composition, avoiding ethical concerns in clinical trials. The goal of the present article is to provide a narrative review of reports on HFD in animal models of AD. Eligibility criteria included mouse models of AD fed a HFD defined as > 35% of fat/weight and western diets containing > 1% cholesterol or > 15% sugar. MEDLINE and Embase databases were searched from 1946 to August 2022, and 32 preclinical studies were included in the review. HFD-induced obesity and metabolic disturbances such as insulin resistance and glucose intolerance have been replicated in most studies, but with methodological variability. Most studies have found an aggravating effect of HFD on brain Aβ pathology, whereas tau pathology has been much less studied, and results are more equivocal. While most reports show HFD-induced impairment on cognitive behavior, confounding factors may blur their interpretation. In summary, despite conflicting results, exposing rodents to diets highly enriched in saturated fat induces not only metabolic defects, but also cognitive impairment often accompanied by aggravated neuropathological markers, most notably Aβ burden. Although there are important variations between methods, particularly the lack of diet characterization, these studies collectively suggest that excessive intake of saturated fat should be avoided in order to lower the incidence of AD. [ABSTRACT FROM AUTHOR]

Background: Increasing evidence has highlighted retinal impairments in neurodegenerative diseases. Dominant mutations in TAR DNA-binding protein 43 (TDP-43) cause amyotrophic lateral sclerosis (ALS), and the accumulation of TDP-43 in the cytoplasm is a pathological hallmark of ALS, frontotemporal dementia (FTD), and many other neurodegenerative diseases. Objective: While homozygous transgenic mice expressing the disease-causing human TDP-43 M337V mutant (TDP-43M337V mice) experience premature death, hemizygous TDP-43M337V mice do not suffer sudden death, but they exhibit age-dependent motor-coordinative and cognitive deficits. This study aims to leverage the hemizygous TDP-43M337V mice as a valuable ALS/FTD disease model for the assessment also of retinal changes during the disease progression. Methods: We evaluated the retinal function of young TDP-43M337V mice by full field electroretinogram (ERG) recordings. Results: At 3–4 months of age, well before the onset of brain dysfunction at 8 months, the ERG responses were notably impaired in the retinas of young female TDP-43M337V mice in contrast to their male counterparts and age-matched non-transgenic mice. Mitochondria have been implicated as critical targets of TDP-43. Further investigation revealed that significant changes in the key regulators of mitochondrial dynamics and bioenergetics were only observed in the retinas of young female TDP-43M337V mice, while these alterations were not present in the brains of either gender. Conclusions: Together our findings suggest a sex-specific vulnerability within the retina in the early disease stage, and highlight the importance of retinal changes and mitochondrial markers as potential early diagnostic indicators for ALS, FTD, and other TDP-43 related neurodegenerative conditions. [ABSTRACT FROM AUTHOR]

Background: Blood-brain barrier (BBB) dysfunction could favor the pathogenesis and progression of Alzheimer's disease (AD). Vascular risk factors (VRF) could worsen BBB integrity, thus promoting neurode generation. Objective: To investigate BBB permeability and its relation with VRF along the AD continuum (ADc). Cerebrospinal fluid (CSF) Amyloid (A) and p-tau (T) levels were used to stratify patients. Methods: We compared CSF/plasma albumin ratio (QAlb) of 131 AD patients and 24 healthy controls (HC). APOE genotype and VRF were evaluated for each patient. Spearman's Rho correlation was used to investigate the associations between Qalb and CSF AD biomarkers. Multivariate regression analyses were conducted to explore the relationship between Qalb and AD biomarkers, sex, age, cognitive status, and VRF. Results: QAlb levels did not show significant difference between ADc patients and HC (p = 0.984). However, QAlb was significantly higher in A + T–compared to A + T+ (p = 0.021). In ADc, CSF p-tau demonstrated an inverse correlation with QAlb, a finding confirmed in APOE4 carriers (p = 0.002), but not in APOE3. Furthermore, in APOE4 carriers, sex, hypertension, and hypercholesterolemia were associated with QAlb (p = 0.004, p = 0.038, p = 0.038, respectively), whereas only sex showed an association in APOE3 carriers (p = 0.026). Conclusions: BBB integrity is preserved in ADc. Among AT categories, A + T–have a more permeable BBB than A + T+. In APOE4 carriers, CSF p-tau levels display an inverse association with BBB permeability, which in turn, seems to be affected by VRF. These data suggest a possible relationship between BBB efficiency, VRF and CSF p-tau levels depending on APOE genotype. [ABSTRACT FROM AUTHOR]

Background: Progranulin protein (GRN) is a growth factor, encoded by the GRN (Granulin precursor) gene, involved in several functions including inflammation, wound repair, signal transduction, proliferation, and tumorigenesis. Mutations in GRN gene are usually the genetic etiology of frontotemporal dementia (FTD), but different studies reported GRN mutations in Alzheimer 's disease (AD) patients. Objective: Here, we analyzed FTD linked gene GRN in 23 patients with a clinical diagnosis of AD and a family history of AD (FAD), not carrying mutations in AD candidate genes (PSEN 1, PSEN 2, and APP). In addition, Microtubule-associated protein tau (MAPT) gene was studied too. All patients underwent an extensive neuropsychological battery. Methods: Genetic analyses were performed thought PCR assay and sequencing. Variants were annotated with ANNOVAR and allele frequency was checked on population databases. In silico prediction tools were consulted to check nonsynonymous variants and their effect on protein function and structure. The clinical data were retrospectively collected from medical records. Results: Genetic screening of MAPT and GRN in 23 FAD patients highlighted two rare different variants in two probands (2/23 = 8,7%) located in GRN gene: R433W (p.Arg433Trp) and C521Y (p.Cys521Tyr). The R433W and C521Y are variants with uncertain significant, that are predicted to affect GRN protein structure and function, with a possible damaging effect. Conclusions: Our data provide evidence of the importance of GRN genetic analysis also in the study of familial AD. [ABSTRACT FROM AUTHOR]

Concomitant Alzheimer's disease (AD) pathology can be observed in approximately 10–15% of cases with amyotrophic lateral sclerosis (ALS). ALS-AD patients have a higher prevalence of amnestic cognitive disturbances, which may often precede motor symptoms. Cerebrospinal fluid (CSF) AD core biomarkers usually show no or slightly significant changes in ALS, whereas blood phosphorylated tau protein might be increased independently from AD copathology. Neurofilament proteins are consistently elevated in CSF and blood of ALS, but have been poorly investigated in ALS-AD. All these issues should be taken into account when using fluid biomarkers as inclusion criteria or secondary endpoints in clinical trials. [ABSTRACT FROM AUTHOR]

We describe a case of amyotrophic lateral sclerosis (ALS) associated with Alzheimer's disease (AD) and review the literature about the coexistence of the two entities, highlighting the following: mean age at onset is 63.8 years, with slight female predominance; ALS tends to manifest after cognitive impairment and often begins in the bulbar region; average disease duration is 3 years; cognitive phenotype is mostly amnestic; the pattern of brain involvement is, in most cases, consistent with AD. Our case and the reviewed ones suggest that patients with ALS and dementia lacking unequivocal features of FTD should undergo additional examinations in order to recognize AD. [ABSTRACT FROM AUTHOR]

Background: The Alzheimer's Disease Anti-inflammatory Prevention Trial (ADAPT) was the first-ever large-scale anti-inflammatory prevention trial targeting Alzheimer's disease. Objective: The overall goal of this study was to evaluate predictive blood biomarker profiles that identified individuals most likely to be responders on NSAID treatment or placebo at 12 and 24 months. Methods: Baseline (n = 193) and 12-month (n = 562) plasma samples were assayed. The predictive biomarker profile was generated using SVM analyses with response on treatment (yes/no) as the outcome variable. Results: Baseline (AUC = 0.99) and 12-month (AUC = 0.99) predictive biomarker profiles were highly accurate in predicting response on Celecoxib arm at 12 and 24 months. The baseline (AUC = 0.95) and 12-month (AUC = 0.9) predictive biomarker profile predicting response on Naproxen were also highly accurate at 12 and 24 months. The baseline (AUC = 0.93) and 12-month (AUC = 0.99) predictive biomarker profile was also highly accurate in predicting response on placebo. As with our prior work, the profiles varied by treatment arm. Conclusions: The current results provide additional support for a precision medicine model for treating and preventing Alzheimer's disease. [ABSTRACT FROM AUTHOR]

Background: Alzheimer's disease (AD) and frontotemporal dementia (FTD) are pathologically distinct neurodegenerative disorders with certain overlap in cognitive and behavioral symptoms. Both AD and FTD are characterized by synaptic loss and accumulation of misfolded proteins, albeit, in different regions of the brain. Objective: To investigate the synaptic and organellar markers in AD and FTD through assessment of the levels of synaptic protein, neurogranin (Ng) and organellar proteins, mitofusin-2 (MFN-2), lysosomal associated membrane protein-2 (LAMP-2), and golgin A4 from neuronal exosomes. Methods: Exosomes isolated from the plasma of healthy controls (HC), AD and FTD subjects were characterized using transmission electron microscopy. Neurodegenerative status was assessed by measurement of neurofilament light chain (NfL) using Simoa. The pooled exosomal extracts from each group were analyzed for Ng, MFN-2, LAMP-2, and golgin A4 by western blot analysis using enhanced chemiluminescence method of detection. Results: The densitometric analysis of immunoreactive bands demonstrated a 65% reduction of Ng in AD and 53% in FTD. Mitochondrial protein MFN-2 showed a significant reduction by 32% in AD and 46% in FTD. Lysosomal LAMP-2 and Golgi complex associated golgin A4 were considerably increased in both AD and FTD. Conclusion: Changes in Ng may reflect the ongoing synaptic degeneration that are linked to cognitive disturbances in AD and FTD. Importantly, the rate of synaptic degeneration was more pronounced in AD. Changes to a similar extent in both the dementia groups in organellar proteins indicates shared mechanisms of protein accumulation/degradation common to both AD and FTD. [ABSTRACT FROM AUTHOR]

Background: Gender, APOE ɛ4 status and age have different effects on brain amyloid deposition in patients with mild cognitively impaired (MCI). Objective: To investigate the effect of gender×APOE ɛ4 status interaction on Aβ deposition in the brains of individuals with MCI in different age groups by PET scanning. Methods: 204 individuals with MCI were classified into younger or older groups based on whether they were under or over 65 years of age. APOE genotyping, structural MRI, amyloid PET scans, and neuropsychological tests were performed. The effect of gender×APOE ɛ4 status interaction on Aβ deposition was assessed in different age groups. Results: APOE ɛ4 carriers had higher amyloid deposition than noncarriers in the whole group. Females with MCI had more amyloid deposition in the medial temporal lobe than males in the whole cohort and younger group. Older individuals with MCI had higher amyloid deposition than younger individuals. In stratified analysis by age, female APOE ɛ4 carriers had significantly increased amyloid deposition compared to their male counterparts only in the medial temporal lobe in the younger group. Amyloid deposition was increased in female APOE ɛ4 carriers compared to noncarriers in the younger group, whereas higher amyloid deposition was observed in male APOE ɛ4 carriers in the older group. Conclusion: Women in the younger group with MCI who were APOE ɛ4 carriers had more amyloid deposition in the brain, while men in the older group with MCI who were APOE ɛ4 carriers had higher amyloid deposition. [ABSTRACT FROM AUTHOR]

Background: Prior work has shown that certain modifiable health, Alzheimer's disease (AD) biomarker, and demographic variables are associated with cognitive performance. However, less is known about the relative importance of these different domains of variables in predicting longitudinal change in cognition. Objective: Identify novel relationships between modifiable physical and health variables, AD biomarkers, and slope of cognitive change over two years in a cohort of older adults with mild cognitive impairment (MCI). Methods: Metrics of cardiometabolic risk, stress, inflammation, neurotrophic/growth factors, and AD pathology were assessed in 123 older adults with MCI at baseline from the Alzheimer's Disease Neuroimaging Initiative (mean age = 73.9; SD = 7.6; mean education = 16.0; SD = 3.0). Partial least squares regression (PLSR)—a multivariate method which creates components that best predict an outcome—was used to identify whether these physiological variables were important in predicting slope of change in episodic memory or executive function over two years. Results: At two-year follow-up, the two PLSR models predicted, respectively, 20.0% and 19.6% of the variance in change in episodic memory and executive function. Baseline levels of AD biomarkers were important in predicting change in both episodic memory and executive function. Baseline education and neurotrophic/growth factors were important in predicting change in episodic memory, whereas cardiometabolic variables such as blood pressure and cholesterol were important in predicting change in executive function. Conclusion: These data-driven analyses highlight the impact of AD biomarkers on cognitive change and further clarify potential domain specific relationships with predictors of cognitive change. [ABSTRACT FROM AUTHOR]

Background: β-site amyloid precursor protein cleaving enzyme 1 (BACE1) is a key enzyme in the formation of amyloid-β (Aβ) protein. Increasing evidence suggests that BACE1 concentration is a potential biomarker for Alzheimer's disease (AD). Objective: To evaluate the correlations between plasma BACE1 concentration, cognition, and hippocampal volume at different stages of the AD continuum. Methods: Plasma BACE1 concentrations were measured in 32 patients with probable dementia due to AD (ADD), 48 patients with mild cognitive impairment (MCI) due to AD, and 40 cognitively unimpaired (CU) individuals. Memory function was evaluated using the auditory verbal learning test (AVLT), and voxel-based morphometry was used to analyze bilateral hippocampal volumes. Correlation and mediation analyses were performed to investigate the associations between plasma BACE1 concentration, cognition, and hippocampal atrophy. Results: The MCI and ADD groups exhibited elevated BACE1 concentrations compared with the CU group after adjusting for age, sex, and apolipoprotein E (APOE) genotype. Increased BACE1 concentration was found in AD continuum patients who were APOE ɛ4 carriers (p < 0.05). BACE1 concentration was negatively associated with the scores of the subitems of the AVLT and hippocampal volume (p < 0.05, false discovery rate correction) in the MCI group. Moreover, bilateral hippocampal volume mediated the relationship between BACE1 concentration and recognition in the MCI group. Conclusion: BACE1 expression increased in the AD continuum, and bilateral hippocampal volume mediated the effect of BACE1 concentration on memory function in patients with MCI. Research has indicated that the plasma BACE1 concentration might be a biomarker at the early stage of AD. [ABSTRACT FROM AUTHOR]

Background: Alzheimer's disease neuropathologic change (ADNC) is defined by the progression of both hyperphosphorylated-tau (p-tau) and amyloid-β (Aβ) and is the most common underlying cause of dementia worldwide. Primary age-related tauopathy (PART), an Aβ-negative tauopathy largely confined to the medial temporal lobe, is increasingly being recognized as an entity separate from ADNC with diverging clinical, genetic, neuroanatomic, and radiologic profiles. Objective: The specific clinical correlates of PART are largely unknown; we aimed to identify cognitive and neuropsychological differences between PART, ADNC, and subjects with no tauopathy (NT). Methods: We compared 2,884 subjects with autopsy-confirmed intermediate-high stage ADNC to 208 subjects with definite PART (Braak stage I–IV, Thal phase 0, CERAD NP score "absent") and 178 NT subjects from the National Alzheimer's Coordinating Center dataset. Results: PART subjects were older than either ADNC or NT patients. The ADNC cohort had more frequent neuropathological comorbidities as well as APOE ɛ4 alleles than the PART or NT cohort, and less frequent APOE ɛ2 alleles than either group. Clinically, ADNC patients performed significantly worse than NT or PART subjects across cognitive measures, but PART subjects had selective deficits in measures of processing speed, executive function, and visuospatial function, although additional cognitive measures were further impaired in the presence of neuropathologic comorbidities. In isolated cases of PART with Braak stage III-IV, there are additional deficits in measures of language. Conclusion: Overall, these findings demonstrate underlying cognitive features specifically associated with PART, and reinforce the concept that PART is a distinct entity from ADNC. [ABSTRACT FROM AUTHOR]

Background: Most research on cerebrospinal fluid (CSF) neurofilament light protein (NfL) as a marker for neurodegeneration and neurogranin (Ng) for synaptic dysfunction has largely focused on clinical cohorts rather than population-based samples. Objective: We hypothesized that increased CSF levels of NfL and Ng are associated with subtle cognitive deficits in cognitively unimpaired (CU) older adults. Methods: The sample was derived from the Gothenburg H70 Birth Cohort Studies and comprised 258 CU 70-year-olds, with a Clinical Dementia Rating score of zero. All participants underwent extensive cognitive testing. CSF levels of NfL and Ng, as well as amyloid β1 - 42, total tau, and phosphorylated tau, were measured. Results: Participants with high CSF NfL performed worse in one memory-based test (Immediate recall, p = 0.013) and a language test (FAS, p = 0.016). Individuals with high CSF Ng performed worse on the memory-based test Supra Span (p = 0.035). When stratified according to CSF tau and Aβ42 concentrations, participants with high NfL and increased tau performed worse on a memory test than participants normal tau concentrations (Delayed recall, p = 0.003). In participants with high NfL, those with pathologic Aβ42 concentrations performed worse on the Delayed recall memory (p = 0.044). In the high Ng group, participants with pathological Aβ42 concentrations had lower MMSE scores (p = 0.027). However, in regression analysis we found no linear correlations between CSF NfL or CSF Ng in relation to cognitive tests when controlled for important co-variates. Conclusion: Markers of neurodegeneration and synaptic pathology might be associated with subtle signs of cognitive decline in a population-based sample of 70-year-olds. [ABSTRACT FROM AUTHOR]

Background: Synaptic disruption precedes neuronal death and correlates with clinical features of Alzheimer's disease (AD). The identification of fluid biomarkers of synaptic damage is emerging as a goal for early and accurate diagnosis of the disease. Objective: To perform a systematic review and meta-analysis to determine whether fluid biomarkers of synaptic damage are impaired in AD. Methods: PubMed, Scopus, EMBASE, and Web of Science were searched for articles reporting synaptic proteins as fluid biomarkers in AD and cognitively unimpaired (CU) individuals. Pooled effect sizes were determined using the Hedge G method with random effects. Questions adapted from the Quality Assessment of Diagnostic Accuracy Studies were applied for quality assessment. A protocol for this study has been previously registered in PROSPERO (registration number: CRD42021277487). Results: The search strategy identified 204 articles that were assessed for eligibility. A total of 23 studies were included in the systematic review and 15 were included in the meta-analysis. For Neurogranin, 827 AD and 1,237 CU subjects were included in the meta-analysis, showing a significant increase in cerebrospinal fluid of patients with AD compared to CU individuals, with an effect size of 1.01 (p < 0.001). A significant increase in SNAP-25 and GAP-43 levels in CSF of patients with AD was observed. Conclusion: Neurogranin, SNAP-25, and GAP-43 are possible biomarkers of synaptic damage in AD, and other potential synaptic biomarkers are emerging. This meta-analysis also revealed that there are still relatively few studies investigating these biomarkers in patients with AD or other dementias and showed wide heterogeneity in literature. [ABSTRACT FROM AUTHOR]

Background: The brain activation patterns of mild cognitive impairment (MCI) are still unclear and they involve multiple brain regions. Most previous studies have focused on abnormal activation in the frontal and temporal lobes, with few investigating the entire brain.Objective: To identify and compare the changes in cerebral hemodynamics and abnormal activation patterns in the entire brain of MCI patients and healthy older adults.Methods: Patients with MCI (n = 22) and healthy controls (HC, n = 34) matched by age, education levels, sex, and mental state were enrolled. They performed the same letter and category verbal fluency test (VFT) tasks while their behavioral performance and global cerebral hemodynamics were analyzed.Results: The performance during the category VFT task was significantly better than that during the letter VFT task across all participants (HC: correct: p < 0.001; intrusions: p < 0.001; MCI: correct: p < 0.001; intrusions: p < 0.001). The number of correct words during the letter and category VFT tasks was significantly higher in the HC group than in the MCI group (p < 0.001). The deoxygenated-hemoglobin (HbR) concentrations in the left parietal lobule (p = 0.022) and left inferior parietal lobule (p = 0.034) were significantly different during the category VFT task.Conclusion: The differences between HC and MCI groups were greater in the category task. The HbR concentration was more sensitive for the category VFT task and concentration changes in the left parietal lobule and left inferior parietal lobule may be useful for clinical screening and application; thus, they deserve more attention. [ABSTRACT FROM AUTHOR]

We examined ethnoracial differences in fatty acid binding protein (FABP)-a family of intracellular lipid carriers-and clarified FABP3 associations with gray and white matter. Relative to Mexican Americans (MAs), FABP3 was higher in Non-Hispanic Whites (NHWS, p < 0.001). Regressions revealed, independent of traditional AD markers, FABP3 was associated with neurodegeneration (B = -0.08, p = 0.003) and WMH burden (B = 0.18, p = 0.03) in MAs, but not in NHWs (ps > 0.18). Findings suggest FABP3 is related to neural health within MAs and highlight its potential as a prognostic marker of brain health in ethnoracially diverse older adults. [ABSTRACT FROM AUTHOR]

Background: An understudied variant of Alzheimer's disease (AD), the behavioral/dysexecutive variant of AD (bvAD), is associated with progressive personality, behavior, and/or executive dysfunction and frontal atrophy. Objective: This study characterizes the neuropsychological and neuroanatomical features associated with bvAD by comparing it to behavioral variant frontotemporal dementia (bvFTD), amnestic AD (aAD), and subjects with normal cognition. Methods: Subjects included 16 bvAD, 67 bvFTD, 18 aAD patients, and 26 healthy controls. Neuropsychological assessment and MRI data were compared between these groups. Results: Compared to bvFTD, bvAD showed more significant visuospatial impairments (Rey Figure copy and recall), more irritability (Neuropsychological Inventory), and equivalent verbal memory (Philadelphia Verbal Learning Test). Compared to aAD, bvAD indicated more executive dysfunction (F-letter fluency) and better visuospatial performance. Neuroimaging analysis found that bvAD showed cortical thinning relative to bvFTD posteriorly in left temporal-occipital regions; bvFTD had cortical thinning relative to bvAD in left inferior frontal cortex. bvAD had cortical thinning relative to aAD in prefrontal and anterior temporal regions. All patient groups had lower volumes than controls in both anterior and posterior hippocampus. However, bvAD patients had higher average volume than aAD patients in posterior hippocampus and higher volume than bvFTD patients in anterior hippocampus after adjustment for age and intracranial volume. Conclusion: Findings demonstrated that underlying pathology mediates disease presentation in bvAD and bvFTD. [ABSTRACT FROM AUTHOR]

Background: There are few studies on the locus coeruleus (LC) in frontotemporal lobar degeneration (FTLD) and the potential differences in the LC related to the underlying proteinopathy.Objective: The aim of this study was to investigate the LC in FTLD subgroups.Methods: Neuropathological cases diagnosed with FTLD were included. The subgroups consisted of FTLD with tau, transactive response DNA-binding protein 43 (TDP) and fused in sarcoma (FUS). Micro- and macroscopical degeneration of the LC were assessed with respect to the number of neurons and the degree of depigmentation. A group of cognitively healthy subjects and a group with vascular cognitive impairment (VCI) served as comparison groups.Results: A total of 85 FTLD cases were included, of which 44 had FTLD-TDP, 38 had FTLD-tau, and three had FTLD-FUS. The groups were compared with 25 VCI cases and 41 cognitively healthy control cases (N = 151 for the entire study). All FTLD groups had a statistically higher microscopical degeneration of the LC compared to the controls, but the FTLD-tau group had greater micro- and macroscopical degeneration than the FTLD-TDP group. Age correlated positively with the LC score in the FTLD-tau group, but not in the FTLD-TDP group.Conclusion: A greater microscopical degeneration of the LC was observed in all FTLD cases compared to healthy controls and those with VCI. The LC degeneration was more severe in FTLD-tau than in FTLD-TDP. The macroscopically differential degeneration of the LC in FTLD subgroups may facilitate differential diagnostics, potentially with imaging. [ABSTRACT FROM AUTHOR]

Background: Phosphatidylethanolamine binding protein 1 (PEBP1) is a multifunctional protein, mainly known for its specific binding of phosphatidylethanolamine and the ability to suppress the Raf1-MAPK pathway. Its potential role as an Alzheimer's disease (AD) biomarker has been proposed in several studies. However, evaluation of its discriminative value in clinical cohorts is missing.Objective: We aimed to develop a new immunoassay for the measurement of PEBP1 in cerebrospinal fluid (CSF) and assess the possible role of this protein as AD biomarker.Methods: We developed a sandwich enzyme-linked immunosorbent assay (ELISA) for detection of PEBP1 in CSF and performed a technical and a clinical validation on two well-characterized cohorts. The first cohort included 14 mild cognitive impairment due to AD (MCI-AD) and 11 other neurological diseases (OND) patients. The second, larger cohort, included 25 MCI-AD, 29 AD dementia (AD-dem), and 21 OND patients.Results: PEBP1 is highly sensitive to pre-analytical conditions, especially to prolonged storage at room temperature or 4°C. Analysis of the first cohort showed a trend of an increase of PEBP1 level in MCI-AD patients versus OND subjects. Analysis of the second cohort did not show significant differences among diagnostic groups. Weak, positive correlation was found between CSF PEBP1 and t-tau, p-tau, and Aβ40 in the AD-dem group.Conclusion: A novel ELISA for the detection of PEBP1 in CSF was developed. Further research is needed to assess the potential of PEBP1 in AD diagnostics. The observed dependence of the PEBP1 signal on operating procedures encourages its potential application as CSF quality control. [ABSTRACT FROM AUTHOR]

Background: Previous research finds a range of numbers impairments in Parkinsonian syndromes (PS), but has largely focused on how visuospatial impairments impact deficits in basic numerical processes (e.g., magnitude judgments, chunking). Differentiation between these basic functions and more complex numerical processes often utilized in everyday tasks may help elucidate neurocognitive and neuroanatomic bases of numbers deficits in PS.Objective: To test neurocognitive and neuroanatomic correlates of complex numerical processing in PS, we assessed number abilities, neuropsychological performance, and cortical thickness in progressive supranuclear palsy (PSP) and Lewy body spectrum disorders (LBSD).Methods: Fifty-six patients (LBSD = 35; PSP = 21) completed a Numbers Battery, including basic and complex numerical tasks. The Mini-Mental State Exam (MMSE), letter fluency (LF), and Judgment of Line Orientation (JOLO) assessed global, executive, and visuospatial functioning respectively. Mann-Whitney U tests compared neuropsychological testing and rank-transformed analysis of covariance (ANCOVA) compared numbers performance between groups while adjusting for demographic variables. Spearman's and partial correlations related numbers performance to neuropsychological tasks. Neuroimaging assessed cortical thickness in disease groups and demographically-matched healthy controls.Results: PSP had worse complex numbers performance than LBSD (F = 6.06, p = 0.02) but similar basic numbers performance (F = 0.38, p > 0.1), covarying for MMSE and sex. Across syndromes, impaired complex numbers performance was linked to poor LF (rho = 0.34, p = 0.01) but not JOLO (rho = 0.23, p > 0.05). Imaging revealed significant frontal atrophy in PSP compared to controls, which was associated with worse LF and complex numbers performance.Conclusion: PSP demonstrated selective impairments in complex numbers processing compared to LBSD. This complex numerical deficit may relate to executive dysfunction and frontal atrophy. [ABSTRACT FROM AUTHOR]

Background: Down syndrome (DS) is frequently associated with Alzheimer's disease (AD)-related neuropathological changes. There are few observations on the spectrum of mixed proteinopathies in DS patients.Objective: This study aimed to evaluate multiple disease-associated proteinopathies in a series of DS cases.Methods: We analyzed the distribution of neurodegenerative disease associated proteins in postmortem brain samples from 11 DS cases (6 females, median age 57, range 38-66 years). Sections were stained for phosphorylated tau, 3-repeat and 4-repeat tau, amyloid-β, alpha synuclein, phosphorylated TDP-43, and p62. A comprehensive anatomical mapping and staging were applied for all proteins.Results: Tau and amyloid-β pathology was prevalent in all cases and compatible with that typically seen in AD with some subtle deviations. Four of 11 cases presented with Lewy-related pathology (LRP). Two cases followed the Braak staging (stage 4 and 5) whereas 2 cases presented with an atypical distribution. Two cases showed limbic predominant age-related TDP-43 encephalopathy (LATE) (stage 1 and stage 2) neuropathologic change. Two cases exhibited aging-related tau astrogliopathy (ARTAG).Conclusion: In addition to subtle deviations from AD regarding the morphology of amyloid-β deposition and distribution of neuronal tau pathology, we find that the spectrum of mixed-pathologies in DS show distinctive features such as deviations from the Braak staging of LRP and that LATE neuropathologic change and ARTAG pathology can be seen in individuals younger than in sporadic AD cases. Our observations support the notion that DS has distinctive pathogenic pathways from sporadic AD. [ABSTRACT FROM AUTHOR]

Background: The Abi3 gene has been suggested to be an important regulator of microglia during Alzheimer's disease (AD), but the diagnostic power of ABI3 in neurodegenerative disease has rarely been reported.Objective: The aim of this study was to evaluate the diagnostic value of ABI3 in AD patients.Methods: ELISAs were used to measure the ABI3 level in the serum and cerebrospinal fluid (CSF) of AD patients as well as in the serum of APP/PS1 mice. RT-PCR and western blot were further performed to detect the expression levels of ABI3 in peripheral blood mononuclear cells (PBMCs) of AD subjects as well as in the hippocampus and cortical tissue of APP/PS1 mice. The correlation of cognitive ability with ABI3 level was estimated by linear regression analysis. Moreover, the diagnostic value of ABI3 for AD was assessed with ROC analysis.Results: The ABI3 levels all decreased significantly in the serum, CSF, and PBMCs of AD patients and showed a good diagnostic performance. In addition, the ABI3 levels were observed to decrease markedly in the hippocampus from 5-month-old mice, but the dramatic change only appeared in the cortical tissue in the 9-month-old APP/PS1 mice. The ABI3 levels in serum and in the hippocampus of APP/PS1 mice were significantly correlated with cognitive capacity.Conclusion: These results demonstrated that ABI3 in serum, CSF, and PBMCs could be a novel early diagnostic biomarker of AD. Moreover, ABI3 had potential to be a novel tracer marker in hippocampus of early AD. [ABSTRACT FROM AUTHOR]

Background: It can be challenging to discriminate between progressive supranuclear palsy (PSP) and frontotemporal dementia (FTD). However, a correct diagnosis is a precondition for targeted treatment strategies and proper patient counseling. There has been a growing interest to identify cerebrospinal fluid (CSF) biomarkers, including neurofilament light chain (NfL).Objective: This systematic review evaluates the existing literature on neurofilament light in CSF aiming to validate its utility for differentiating FTD from PSP.Methods: A systematic literature search was conducted. A broad range of synonyms for PSP, NfL, and FTD as well as associated MeSH terms, were combined and used as keywords when searching. Relevant data were extracted and assessed for risk of bias.Results: Nine studies including a total of 671 patients with FTD, 254 patients with PSP, 523 healthy controls, and 1,771 patients with other disorders were included in the review. Four studies found a significantly higher level of CSF NfL in FTD (n = 445) compared to PSP (n = 124); however, in three of these studies the difference was only significant in certain FTD variants. Four studies found no significant difference in CSF NfL between PSP (n = 98) and FTD (n = 248). One study found a significantly higher level of NfL in PSP (n = 33) compared to FTD (n = 16).Conclusion: In the majority of patients in the studies included in this review, a higher level of NfL in CSF was found in patients with FTD compared to patients with PSP; however, results were inconsistent and prospective studies including large study cohorts are needed. [ABSTRACT FROM AUTHOR]

Background: Biochemical and clinical biomarkers correlate with progression rate and disease severity in Parkinson's disease (PD) but are not sufficiently studied in late PD. Objective: To examine how serum neurofilament light chain (S-NfL) alone or combined with clinical classifications predicts PD outcome in later disease stages. Methods: Eighty-five patients with 7.9±5.1 years of PD duration were included in an observational cohort. Clinical scores were obtained at two separate examinations 8.2±2.0 years apart. S-NfL levels were determined with single molecule array (SiMoA). Five predefined disease progression milestones were assessed. After affirming combination potential of S-NfL and either of two clinical classifications, three combined models were constructed based on these factors and age at onset in different combinations. Results: S-NfL levels showed significant hazard ratios for four out of five disease progression milestones: walking-aid usage (HR 3.5; 95% CI 1.4–8.5), nursing home living (5.1; 2.1–12.5), motor end-stage (6.2; 2.1–17.8), and death (4.1; 1.7–9.7). Higher S-NfL levels were associated with lower ability in activities of daily living and poorer cognition at baseline and/or at follow-up. Combined models showed significantly improved area under receiver operating characteristic curves (0.77–0.91) compared to S-NfL levels alone (0.68–0.71) for predicting the five disease milestones. Conclusion: S-NfL levels stratified patients according to their likelihood to reach clinically relevant progression milestones during this long-term observational study. S-NfL alone reflected motor and social outcomes in later stages of PD. Combining S-NfL with clinical factors was possible and exploratory combined models improved prognostic accuracy. [ABSTRACT FROM AUTHOR]

Background: Delirium is a serious acute neuropsychiatric condition associated with altered attention and arousal. Objective: To evaluate simple bedside tests for attention and arousal to detect delirium in those with and without Parkinson's disease (PD) and dementia. Methods: Participants from two prospective delirium studies were pooled comprising 30 with PD without cognitive impairment, 24 with Lewy body cognitive impairment (PD dementia or dementia with Lewy bodies), 16 with another dementia and 179 PD and dementia-free older adults. Participants completed standardised delirium assessments including tests of attention: digit span, Memorial Delirium Assessment Scale (MDAS) attention and months of the year backwards; and arousal: Glasgow Coma Scale (GSC), Observational Scale of Level of Arousal (OSLA), Modified Richmond Agitation Scale and MDAS consciousness. Delirium was diagnosed using the DSM-5 criteria. Results: On their first admission, 21.7%participants had prevalent delirium. Arousal measures accurately detected delirium in all participants (p < 0.01 for all), but only selected attention measures detected delirium in PD and dementia. In PD and dementia-free older adults, impaired digit span and OSLA were the optimal tests to detect delirium (area under the curve [AUC] = 0.838, p < 0.001) while in PD and dementia the optimal tests were MDAS attention and GCS (AUC=0.90 and 0.84, respectively, p < 0.001 for both). Conclusion: Simple bedside tests of attention and arousal at a single visit could accurately detect delirium in PD, dementia and PD and dementia-free older adults; however, the optimal tests differed between groups. Combined attention and arousal scores increased accuracy, which could have clinical utility to aid the identification of delirium neurodegenerative disorders. [ABSTRACT FROM AUTHOR]

Background: Synaptic degeneration has been suggested as an early pathological event that strongly correlates with severity of dementia in Alzheimer's disease (AD). However, changes in longitudinal cerebrospinal fluid (CSF) growth-associated protein 43 (GAP-43) as a synaptic biomarker in the AD continuum remain unclear.Objective: To assess the trajectory of CSF GAP-43 with AD progression and its association with other AD hallmarks.Methods: CSF GAP-43 was analyzed in 788 participants from the Alzheimer's Disease Neuroimaging Initiative (ADNI), including 246 cognitively normal (CN) individuals, 415 individuals with mild cognitive impairment (MCI), and 127 with AD dementia based on cognitive assessments. The associations between a multimodal classification scheme with amyloid-β (Aβ), tau, and neurodegeneration, and changes in CSF GAP-43 over time were also analyzed.Results: CSF GAP-43 levels were increased at baseline in MCI and dementia patients, and increased significantly over time in the preclinical (Aβ-positive CN), prodromal (Aβ-positive MCI), and dementia (Aβ-positive dementia) stages of AD. Higher levels of CSF GAP-43 were also associated with higher CSF phosphorylated tau (p-tau) and total tau (t-tau), cerebral amyloid deposition and hypometabolism on positron emission tomography, the hippocampus and middle temporal atrophy, and cognitive performance deterioration at baseline and follow-up. Furthermore, CSF GAP-43 may assist in effectively predicting the probability of dementia onset at 2- or 4-year follow-up.Conclusion: CSF GAP-43 can be used as a potential biomarker associated with synaptic degeneration in subjects with AD; it may also be useful for tracking the disease progression and for monitoring the effects of clinical trials. [ABSTRACT FROM AUTHOR]

Background: Actuarial and statistical methods have been proposed as alternatives to conventional methods of diagnosing mild cognitive impairment (MCI), with the aim of enhancing diagnostic and prognostic validity, but have not been compared in racially diverse samples.Objective: We compared the agreement of consensus, actuarial, and statistical MCI diagnostic methods, and their relationship to race and prognostic indicators, among diverse older adults.Methods: Participants (N = 354; M age = 71; 68% White, 29% Black) were diagnosed with MCI or normal cognition (NC) according to clinical consensus, actuarial neuropsychological criteria (Jak/Bondi), and latent class analysis (LCA). We examined associations with race/ethnicity, longitudinal cognitive and functional change, and incident dementia.Results: MCI rates by consensus, actuarial criteria, and LCA were 44%, 53%, and 41%, respectively. LCA identified three MCI subtypes (memory; memory/language; memory/executive) and two NC classes (low normal; high normal). Diagnostic agreement was substantial, but agreement of the actuarial method with consensus and LCA was weaker than the agreement between consensus and LCA. Among cases classified as MCI by actuarial criteria only, Black participants were over-represented, and outcomes were generally similar to those of NC participants. Consensus diagnoses best predicted longitudinal outcomes overall, whereas actuarial diagnoses best predicted longitudinal functional change among Black participants.Conclusion: Consensus diagnoses optimize specificity in predicting dementia, but among Black older adults, actuarial diagnoses may be more sensitive to early signs of decline. Results highlight the need for cross-cultural validity in MCI diagnosis and should be explored in community- and population-based samples. [ABSTRACT FROM AUTHOR]

Systemic inflammation is an organism's response to an assault by the non-self. However, that inflammation may predispose humans to illnesses targeted to organs, including Alzheimer's disease (AD). Lesions in AD have pro-inflammatory cytokines and activated microglial/monocyte/macrophage cells. Up to this point, clinical trials using anti-amyloid monoclonal antibodies have not shown success. Maybe it is time to look elsewhere by combating inflammation. Neuroinflammation with CNS cellular activation and excessive expression of immune cytokines is suspected as the "principal culprit" in the higher risk for sporadic AD. Microglia, the resident immune cell of the CNS, perivascular myeloid cells, and activated macrophages produce IL-1, IL-6 at higher levels in patients with AD. Anti-inflammatory measures that target cellular/cytokine-mediated damage provide a rational therapeutic strategy. We propose a clinical trial using oral type 1 IFNs to act as such an agent; one that decreases IL-1 and IL-6 secretion by activating lamina propria lymphocytes in the gut associated lymphoid tissue with subsequent migration to the brain undergoing inflammatory responses. A clinical trial would be double-blind, parallel 1-year clinical trial randomized 1 : 1 oral active type 1 IFN versus best medical therapy to determine whether ingested type I IFN would decrease the rate of cognitive decline in mild cognitive impairment or mild AD. Using cognitive psychometrics, imaging, and fluid biomarkers (MxA for effective type I IFN activity beyond the gut), we can determine if oral type I IFN can prevent cognitive decline in AD. [ABSTRACT FROM AUTHOR]

Amyotrophic lateral sclerosis (ALS) and frontotemporal dementia have a strong clinical, genetic, and pathological connection but association of ALS with Alzheimer's disease (AD) is seldom reported. We report a series of 5 cases of AD associated with ALS. Our patients presented with cognitive deterioration with episodic memory impairment meeting criteria for AD. ALS occurred subsequently in all cases and its phenotype was not homogenous. Amyloid process was confirmed in four cases with cerebrospinal fluid biomarkers. One case underwent postmortem exam, demonstrating hallmarks lesions of both diseases. This series highlights that ALS-AD phenotype could be a specific underexplored entity. [ABSTRACT FROM AUTHOR]

Background: C9orf72 repeat expansion (C9exp) is the most common genetic cause underlying frontotemporal lobar degeneration (FTLD) and amyotrophic lateral sclerosis (ALS). However, detection of the C9exp requires elaborative methods.Objective: Identification of C9exp carriers from genotyped cohorts could be facilitated by using single nucleotide polymorphisms (SNPs) as markers for the C9exp.Methods: We elucidated the potential of the previously described Finnish risk haplotype, defined by the SNP rs3849942, to identify potential C9exp carriers among 218,792 Finns using the FinnGen database. The haplotype approach was first tested in an idiopathic normal pressure hydrocephalus (iNPH) patient cohort (European Alzheimer's Disease DNA BioBank) containing C9exp carriers by comparing intermediate (15-30) and full-length (> 60 repeats) C9exp carriers (n = 41) to C9exp negative patients (< 15 repeats, n = 801).Results: In this analysis, rs3849942 was associated with carriership of C9exp (OR 8.44, p < 2×10-15), while the strongest association was found with rs139185008 (OR 39.4, p < 5×10-18). Unbiased analysis of rs139185008 in FinnGen showed the strongest association with FTLD (OR 4.38, 3×10-15) and motor neuron disease ALS (OR 5.19, 3×10-21). rs139185008 was the top SNP in all diseases (iNPH, FTLD, ALS), and further showed a strong association with ALS in the UK Biobank (p = 9.0×10-8).Conclusion: Our findings suggest that rs139185008 is a useful marker to identify potential C9exp carriers in the genotyped cohorts and biobanks originating from Finland. [ABSTRACT FROM AUTHOR]

Background: In Alzheimer's disease (AD), an increase in inflammation is distinctive. Amyloid precursor protein plus presenilin-1 (APP/PS1 mice) is a model for this illness. Chemokines secreted by central nervous system (CNS) cells could play multiple important roles in AD. Data looking for the chemokines involved in inflammatory mechanisms are lacking. To understand the changes that occur in the inflammation process in AD, it is necessary to improve strategies to act on specific inflammatory targets.Objective: Chemokines and their receptors involved in phagocytosis, demyelination, chemotaxis, and coagulation were the objective of our study.Methods: Female APPswe/PS1 double-transgenic mice (B6C3-Tg) were used and cortex brain from 20-22-month-old mice obtained and used to quantify chemokines and chemokine receptors expression using RT-PCR technique.Results: Significant inflammatory changes were detected in APP/PS1 compared to wild type mice. CCR1, CCR3, CCR4, and CCR9 were elevated, and CCR2 were decreased compared with wild type mice. Their ligands CCL7, CCL11, CCL17, CCL22, CCL25, and CXCL4 showed an increase expression; however, changes were not observed in CCL2 in APP/PS1 compared to wild type mice.Conclusion: This change in expression could explain the differences between AD patients and elderly people without this illness. This would provide a new strategy for the treatment of AD, with the possibility to act in specific inflammatory targets. [ABSTRACT FROM AUTHOR]

Background: Studies have suggested a connection between a decrease in the levels of polyunsaturated fatty acids (PUFAs) and Alzheimer's disease (AD). We aimed to assess the effect of supplementation with omega-3 fatty acids (n-3 FAs) on biomarkers analyzed in the cerebrospinal fluid (CSF) of patients diagnosed with AD.Objective: To investigate the effects of daily supplementation with 2.3 g of PUFAs in AD patients on the biomarkers in CSF described below. We also explored the possible correlation between these biomarkers and the performance in the cognitive test Mini-Mental State Examination (MMSE).Methods: Thirty-three patients diagnosed with AD were randomized to either treatment with a daily intake of 2.3 g of n-3 FAs (n  =  18) or placebo (n  =  15). CSF samples were collected at baseline and after six months of treatment, and the following biomarkers were analyzed: Aβ 38, Aβ 40, Aβ 42, t-tau, p-tau, neurofilament light (NfL), chitinase-3-like protein 1 (YKL-40), acetylcholinesterase (AChE), butyrylcholinesterase (BuChE), soluble IL-1 receptor type II (sIL-1RII), and IL-6.Results: There were no significant differences between the groups concerning the level of the different biomarkers in the CSF at baseline. Within the treatment group, there was a small but significant increase in both YKL-40 (p = 0.04) and NfL (p = 0.03), while the other CSF biomarkers remained stable.Conclusion: Supplementation with n-3 FAs had a statistically significant effect on NfL and YKL-40, resulting in an increase of both biomarkers, indicating a possible increase of inflammatory response and axonal damage. This increase in biomarkers did not correlate with MMSE score. [ABSTRACT FROM AUTHOR]

Background: Cerebrospinal fluid (CSF) neurogranin and quantitative electroencephalography (qEEG) are potential molecular and functional markers of synaptic pathology in Alzheimer's disease (AD). Synaptic markers have emerged as candidate prognostic indicators of AD since synaptic degeneration was shown to be an early event and the best correlate of cognitive deficits in patients along the disease continuum.Objective: The present study investigated the association between CSF neurogranin and qEEG measures as well as their potential to predict clinical deterioration in mild cognitive impairment (MCI) patients.Methods: Patients diagnosed with MCI (n = 99) underwent CSF conventional AD biomarkers and neurogranin analysis and resting-state EEG recordings. The study population was further stratified into stable (n = 41) and progressive MCI (n = 31), based on the progression to AD dementia during two years follow-up. qEEG analysis included computation of global field power and global field synchronization in four conventional frequency bands.Results: CSF neurogranin levels were associated with theta power and synchronization in the progressive MCI group. CSF neurogranin and qEEG measures were significant predictors of progression to AD dementia, independent of baseline amyloid status in MCI patients. A combination of CSF neurogranin with global EEG power in theta and global EEG synchronization in beta band exhibited the highest classification accuracy as compared to either of these markers alone.Conclusion: qEEG and CSF neurogranin are independent predictors of progression to AD dementia in MCI patients. Molecular and neurophysiological synaptic markers may have additive value in a multimodal diagnostic and prognostic approach to dementia. [ABSTRACT FROM AUTHOR]

Plasma neurofilament light chain (NfL) is a marker of neuronal damage in different neurological disorders and might predict disease progression in dementia with Lewy bodies (DLB). The study enrolled 45 controls and 44 DLB patients (including 17 prodromal cases) who underwent an extensive assessment at baseline and at 2 years follow-up. At baseline, plasma NfL levels were higher in both probable DLB and prodromal cases compared to controls. Plasma NfL emerged as the best predictor of cognitive decline compared to age, sex, and baseline severity variables. The study supports the role of plasma NfL as a useful prognostic biomarker from the early stages of DLB. [ABSTRACT FROM AUTHOR]

Background: Late-life cognitive function is heterogeneous, ranging from no decline to severe dementia. Prior studies of cognitive trajectories have tended to focus on a single measure of global cognition or individual tests scores, rather than considering longitudinal performance on multiple tests simultaneously.Objective: The current study aimed to examine cognitive trajectories from two independent datasets to assess whether similar patterns might describe longitudinal cognition in the decade preceding death, as well as what participant characteristics were associated with trajectory membership.Methods: Data were drawn from autopsied longitudinally followed participants of two cohorts (total N = 1,346), community-based cohort at the University of Kentucky Alzheimer's Disease Research Center (n = 365) and National Alzheimer's Coordinating Center (n = 981). We used group-based multi-trajectory models (GBMTM) to identify cognitive trajectories over the decade before death using Mini-Mental State Exam, Logical Memory-Immediate, and Animal Naming performance. Multinomial logistic and Random Forest analyses assessed characteristics associated with trajectory groups.Results: GBMTM identified four similar cognitive trajectories in each dataset. In multinomial models, death age, Braak neurofibrillary tangles (NFT) stage, TDP-43, and α-synuclein were associated with declining trajectories. Random Forest results suggested the most important trajectory predictors were Braak NFT stage, cerebral atrophy, death age, and brain weight. Multiple pathologies were most common in trajectories with moderate or accelerated decline.Conclusion: Cognitive trajectories associated strongly with neuropathology, particularly Braak NFT stage. High frequency of multiple pathologies in trajectories with cognitive decline suggests dementia treatment and prevention efforts must consider multiple diseases simultaneously. [ABSTRACT FROM AUTHOR]

Alzheimer's disease (AD) is a serious neurodegenerative disease, which seriously affects the behavior, cognition, and memory of patients. Studies have shown that sensory stimulation can effectively improve the cognition and memory of AD patients, and its role in brain plasticity and neural regulation is initially revealed. This paper aims to review the effect of various sensory stimulation and multisensory stimulation for AD, and to explain the possible mechanism, so as to provide some new ideas for further research in this field. We searched the Web of Science and PubMed databases (from 2000 to October 27, 2020) for literature on the treatment of AD with sensory and multisensory stimulation, including music therapy, aromatherapy, rhythmic (e.g., visual or acoustic) stimulation, light therapy, multisensory stimulation, and virtual reality assisted therapy, then conducted a systematic analysis. Results show these sensory and multisensory stimulations can effectively ameliorate the pathology of AD, arouse memory, and improve cognition and behaviors. What's more, it can cause brain nerve oscillation, enhance brain plasticity, and regulate regional cerebral blood flow. Sensory and multisensory stimulation are very promising therapeutic methods, and they play an important role in the improvement and treatment of AD, but their potential mechanism and stimulation parameters need to be explored and improved. [ABSTRACT FROM AUTHOR]

Background: Progressive supranuclear palsy syndrome (PSPS) and corticobasal syndrome (CBS) as well as non-fluent/agrammatic primary progressive aphasia (naPPA) are often associated with misfolded 4-repeat tau pathology, but the diversity of the associated speech features is poorly understood.Objective: Investigate the full range of acoustic and lexical properties of speech to test the hypothesis that PSPS-CBS show a subset of speech impairments found in naPPA.Methods: Acoustic and lexical measures, extracted from natural, digitized semi-structured speech samples using novel, automated methods, were compared in PSPS-CBS (n = 87), naPPA (n = 25), and healthy controls (HC, n = 41). We related these measures to grammatical performance and speech fluency, core features of naPPA, to neuropsychological measures of naming, executive, memory and visuoconstructional functioning, and to cerebrospinal fluid (CSF) phosphorylated tau (pTau) levels in patients with available biofluid analytes.Results: Both naPPA and PSPS-CBS speech produced shorter speech segments, longer pauses, higher pause rates, reduced fundamental frequency (f0) pitch ranges, and slower speech rate compared to HC. naPPA speech was distinct from PSPS-CBS with shorter speech segments, more frequent pauses, slower speech rate, reduced verb production, and higher partial word production. In both groups, acoustic duration measures generally correlated with speech fluency, measured as words per minute, and grammatical performance. Speech measures did not correlate with standard neuropsychological measures. CSF pTau levels correlated with f0 range in PSPS-CBS and naPPA.Conclusion: Lexical and acoustic speech features of PSPS-CBS overlaps those of naPPA and are related to CSF pTau levels. [ABSTRACT FROM AUTHOR]

Background: Neurofilament light (NfL) can reflect the extent of neuron/axon damage, thus providing an opportunity to examine the severity and progression of the diseases with such damage. Objective: Whether serum NfL can be used as an indicator to monitor the cognitive progress of de novo Parkinson's disease (PD) remains unclear. Methods: In this research, 144 healthy controls and 301 de novo PD patients from Parkinson's Progression Markers Initiative (PPMI) were recruited. Linear mixed effects models were used to examine the associations of baseline/longitudinal serum NfL with cognitive decline. Cox regression was used to detect cognitive progression in PD participants. Results: We found PD patients had higher serum NfL than controls at baseline (p = 0.031), and NfL increase was faster in PD group (p < 0.001). Both baseline serum NfL and its rate of change predicted measurable cognitive decline in early PD (MoCA, β= –0.014, p < 0.001; β= –0.002, p < 0.001, respectively). Additionally, we observed that NfL levels were also able to predict progression in different diagnostic groups and Amyloid- PD and Amyloid+PD groups. After an average follow-up of 6.37±1.84 years, the baseline NfL of the third tertile of high concentrations was associated with a future high risk of PD dementia (adjusted HR 6.33, 95% CI 2.62–15.29, p < 0.001). Conclusion: In conclusion, our results indicated that the serum NfL concentration could function as an easily accessible biomarker to monitor the severity and progression of cognitive decline in PD. [ABSTRACT FROM AUTHOR]

Background: Understanding how dysregulation in lipid metabolism relates to the severity of Alzheimer's disease (AD) pathology might be critical in developing effective treatments.Objective: To identify lipid species in cerebrospinal fluid (CSF) associated with signature AD pathology and to explore their relationships with measures reflecting AD-related processes (neurodegeneration, inflammation, deficits in verbal episodic memory) among subjects at the pre- and early symptomatic stages of dementia.Methods: A total of 60 subjects that had been referred to an Icelandic memory clinic cohort were classified as having CSF AD (n = 34) or non-AD (n = 26) pathology profiles. Untargeted CSF lipidomic analysis was performed using ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS) for the detection of mass-to-charge ratio (m/z) features. CSF proteins reflecting neurodegeneration (neurofilament light [NFL]) and inflammation (chitinase-3-like protein 1 [YKL-40], S100 calcium-binding protein B [S100B], glial fibrillary acidic protein [GFAP]) were also measured. Rey Auditory Verbal Learning (RAVLT) and Story tests were used for the assessment of verbal episodic memory.Results: Eight out of 1008 features were identified as best distinguishing between the CSF profile groups. Of those, only the annotation of the m/z feature assigned to lipid species C18 ceramide was confirmed with a high confidence. Multiple regression analyses, adjusted for age, gender, and education, demonstrated significant associations of CSF core AD markers (Aβ42: st.β= -0.36, p = 0.007; T-tau: st.β= 0.41, p = 0.005) and inflammatory marker S100B (st.β= 0.51, p = 0.001) with C18 ceramide levels.Conclusion: Higher levels of C18 ceramide associated with increased AD pathology and inflammation, suggesting its potential value as a therapeutic target. [ABSTRACT FROM AUTHOR]

Alzheimer's disease (AD) research is entering a unique moment in which enormous information about the molecular basis of this disease is being translated into therapeutics. However, almost all drug candidates have failed in clinical trials over the past 30 years. These many trial failures have highlighted a need for the incorporation of biomarkers in clinical trials to help improve the trial design. Fluid biomarkers measured in cerebrospinal fluid and circulating blood, which can reflect the pathophysiological process in the brain, are becoming increasingly important in AD clinical trials. In this review, we first succinctly outline a panel of fluid biomarkers for neuropathological changes in AD. Then, we provide a comprehensive overview of current and future application of fluid biomarkers in clinical trials for AD. We also summarize the many challenges that have been encountered in efforts to integrate fluid biomarkers in clinical trials, and the barriers that have begun to be overcome. Ongoing research efforts in the field of fluid biomarkers will be critical to make significant progress in ultimately unveiling disease-modifying therapies in AD. [ABSTRACT FROM AUTHOR]

Background: Longitudinal changes in cerebrospinal fluid (CSF) biomarkers are seldom studied. Furthermore, data on biomarker gradient between lumbar (L-) and ventricular (V-) compartments seems to be discordant.Objective: To examine alteration of CSF biomarkers reflecting Alzheimer's disease (AD)-related amyloid-β (Aβ) aggregation, tau pathology, neurodegeneration, and early synaptic degeneration by CSF shunt surgery in idiopathic normal pressure hydrocephalus (iNPH) in relation to AD-related changes in brain biopsy. In addition, biomarker levels in L- and V-CSF were compared.Methods: L-CSF was collected prior to shunt placement and, together with V-CSF, 3-73 months after surgery. Thereafter, additional CSF sampling took place at 3, 6, and 18 months after the baseline sample from 26 iNPH patients with confirmed Aβ plaques in frontal cortical brain biopsy and 13 iNPH patients without Aβ pathology. CSF Amyloid-β42 (Aβ42), total tau (T-tau), phosphorylated tau (P-tau181), neurofilament light (NFL), and neurogranin (NRGN) were analyzed with customized ELISAs.Results: All biomarkers but Aβ42 increased notably by 140-810% in L-CSF after CSF diversion and then stabilized. Aβ42 instead showed divergent longitudinal decrease between Aβ-positive and -negative patients in L-CSF, and thereafter increase in Aβ-negative iNPH patients in both L- and V-CSF. All five biomarkers correlated highly between V-CSF and L-CSF (Aβ42 R = 0.87, T-tau R = 0.83, P-tau R = 0.92, NFL R = 0.94, NRGN R = 0.9; all p < 0.0001) but were systematically lower in V-CSF (Aβ42 14 %, T-tau 22%, P-tau 20%, NFL 32%, NRGN 19%). With APOE genotype-grouping, only Aβ42 showed higher concentration in non-carriers of allele ɛ4.Conclusion: Longitudinal follow up shows that after an initial post-surgery increase, T-tau, P-tau, and NRGN are stable in iNPH patients regardless of brain biopsy Aβ pathology, while NFL normalized toward its pre-shunt levels. Aβ42 as biomarker seems to be the least affected by the surgical procedure or shunt and may be the best predictor of AD risk in iNPH patients. All biomarker concentrations were lower in V- than L-CSF yet showing strong correlations. [ABSTRACT FROM AUTHOR]

Background: Observational studies in Parkinson's disease (PD) have focused on relatively small numbers of research participants who are studied extensively. The Molecular Integration in Neurological Diagnosis Initiative at the University of Pennsylvania aims to characterize molecular and clinical features of PD in every patient in a large academic center. Objective: To determine the feasibility and interest in a global-capture biomarker research protocol. Additionally, to describe the clinical characteristics and GBA and LRRK2 variant carrier status among participants. Methods: All patients at UPenn with a clinical diagnosis of PD were eligible. Informed consent included options for access to the medical record, future recontact, and use of biosamples for additional studies. A blood sample and a completed questionnaire were obtained from participants. Targeted genotyping for four GBA and eight LRRK2 variants was performed, with plasma and DNA banked for future research. Results: Between September 2018 and December 2019, 704 PD patients were approached for enrollment; 652 (92.6%) enrolled, 28 (3.97%) declined, and 24 (3.41%) did not meet eligibility criteria. Median age was 69 (IQR 63_75) years, disease duration was 5.41 (IQR 2.49_9.95) years, and 11.10%of the cohort was non-white. Disease risk-associated variants in GBA were identified in 39 participants (5.98%) and in LRRK2 in 16 participants (2.45%). Conclusions: We report the clinical and genetic characteristics of PD patients in an all-comers, global capture protocol from an academic center. Patient interest in participation and yield for identification of GBA and LRRK2 mutation carriers is high, demonstrating feasibility of PD clinic-wide molecular characterization. [ABSTRACT FROM AUTHOR]

Huntington's disease (HD) (OMIM 143100) is caused by an expanded CAG repeat tract in the HTT gene. The inherited CAG length is known to expand further in somatic and germline cells in HD subjects. Age at onset of the disease is inversely correlated with the inherited CAG length, but is further modulated by a series of genetic modifiers which are most likely to act on the CAG repeat in HTT that permit it to further expand. Longer repeats are more prone to expansions, and this expansion is age dependent and tissue-specific. Given that the inherited tract expands through life and most subjects develop disease in mid-life, this implies that in cells that degenerate, the CAG length is likely to be longer than the inherited length. These findings suggest two thresholds— the inherited CAG length which permits further expansion, and the intracellular pathogenic threshold, above which cells become dysfunctional and die. This two-step mechanism has been previously proposed and modelled mathematically to give an intracellular pathogenic threshold at a tract length of 115 CAG (95% confidence intervals 70– 165 CAG). Empirically, the intracellular pathogenic threshold is difficult to determine. Clues from studies of people and models of HD, and from other diseases caused by expanded repeat tracts, place this threshold between 60– 100 CAG, most likely towards the upper part of that range. We assess this evidence and discuss how the intracellular pathogenic threshold in manifest disease might be better determined. Knowing the cellular pathogenic threshold would be informative for both understanding the mechanism in HD and deploying treatments. [ABSTRACT FROM AUTHOR]

Primary progressive aphasia (PPA) forms the spectrum of language variants of frontotemporal lobar degeneration (FTLD), including three subtypes each consisting of distinctive speech and language features. Repeat expansion in C9orf72 gene is the most common genetic cause of FTLD. However, thus far only little is known about the effects of the C9orf72 repeat expansion on the phenotype of PPA. This retrospective study aimed at determining the differences between the PPA phenotypes of the C9orf72 expansion carriers and non-carriers. Our results demonstrated no significant differences between these groups, indicating that the C9orf72 repeat expansion does not substantially affect the phenotype of PPA. [ABSTRACT FROM AUTHOR]

Background: Alzheimer's disease (AD) disproportionately affects females with steeper cognitive decline and more neuropathology compared to males, which is exacerbated in females carrying the APOEɛ4 allele. The risk of developing AD is also higher in female APOEɛ4 carriers in earlier age groups (aged 65-75), and the progression from cognitively normal to mild cognitive impairment (MCI) and to AD may be influenced by sex. Inflammation is observed in AD and is related to aging, stress, and neuroplasticity, and although studies are scarce, sex differences are noted in inflammation.Objective: The objective of this study was to investigate underlying physiological inflammatory mechanisms that may help explain why there are sex differences in AD and APOEɛ4 carriers.Methods: We investigated, using the ADNI database, the effect of sex and APOE genotype (non-carriers or carriers of 1 and 2 APOEɛ4 alleles) and sex and diagnosis (cognitively normal (CN), MCI, AD) on CSF (N = 279) and plasma (N = 527) markers of stress and inflammation.Results: We found CSF IL-16 and IL-8 levels differed by sex and APOE genotype, as IL-16 was higher in female APOEɛ4 carriers compared to non-carriers, while the opposite pattern was observed in males with IL-8. Furthermore, females had on average higher levels of plasma CRP and ICAM1 but lower levels of CSF ICAM1, IL-8, IL-16, and IgA than males. Carrying APOEɛ4 alleles and diagnosis (MCI and AD) decreased plasma CRP in both sexes.Conclusion: Sex and APOE genotype differences in CSF and plasma inflammatory biomarkers support that the underlying physiological changes during aging differ by sex and tissue origin. [ABSTRACT FROM AUTHOR]

Background: Synaptopathy is critical in pathophysiology of Parkinson's disease (PD). Cerebrospinal fluid (CSF) levels of neurogranin (NG) and amyloid-β42 (Aβ42) are considered markers of synaptic dysfunction in neurodegenerative diseases.Objective: To evaluate the CSF synaptopathy-related biomarkers, especially the novel Aβ42/NG ratio, in PD, establishing possible associations with cognitive level and other clinical parameters.Methods: Levels of NG, Aβ42, amyloid-β40, total and phosphorylated tau, and Aβ42/NG ratio were measured in 30 PD patients and 30 controls and correlated with cognitive and motor parameters. The accuracy in distinguishing the cognitive status was determined.Results: NG and Aβ42 were significantly reduced in PD, with higher NG levels in patients with worse cognition. The Aβ42/NG ratio showed a direct correlation with Mini-Mental State Examination, independently from age and sex, and differentiated cognitively impaired patients with 92% sensitivity and 71.4% specificity, accuracy higher than NG alone. No correlations resulted with motor disturbances or therapy.Conclusions: The novel Aβ42/NG ratio couples either presynaptic or postsynaptic markers of synaptic dysfunction, representing a potential global index of synaptopathy, useful to track cognitive functions in PD. [ABSTRACT FROM AUTHOR]

Background: Alzheimer's disease, frontotemporal lobar degeneration, dementia with Lewy bodies, and Parkinson's disease (PD) overlap in clinical characteristics, neuropathology, and genetics.Objective: The aim of this study was to evaluate the role of pathogenic mutations and rare variants in genes associated with PD among early-onset dementia (EOD) patients.Methods: Rare non-synonymous variants (MAF < 0.01) in ten genes (SNCA, PARK2, PARK7, LRRK2, PINK1, ATP13A2, UCHL1, HTRA2, GBA, and SNCAIP) and low-frequency (MAF < 0.05) GBA variants were screened using a targeted next-generation sequencing panel in a strictly defined cohort of 37 early-onset (age at onset (AAO) <65 years) dementia patients presenting with atypical features (e.g., myoclonia or spasticity), rapidly progressive course of the disease or with a family history of dementia. The identified variations were further screened in a larger cohort of EOD (n = 279, mean AAO 57, range 36-65) patients.Results: No pathogenic mutations were found, but we identified seven possible risk variants for neurodegeneration (LRRK2 p.Arg793Met, PARK2 p.Ala82Glu, SNCAIP p.Arg240Gln, SNCAIP p.Phe369Leu, GBA p.Asn409Ser, GBA p.Glu365Lys, GBA p.Thr408Met).Discussion: Altogether, the frequency of these variants was two times higher in the first selected cohort compared to the whole cohort. This suggests that specific rare variants in the genes associated with PD might play a role also especially in familial EOD. [ABSTRACT FROM AUTHOR]

Background: Alzheimer's disease (AD) is the most prevalent form of dementia with two pathological hallmarks of tau-containing neurofibrillary tangles and amyloid-β protein (Aβ)-containing neuritic plaques. Although Aβ and tau have been explored as potential biomarkers, levels of these pathological proteins in blood fail to distinguish AD from healthy control subjects.Objective: We aim to discover potential plasma proteins associated with AD pathology by performing tandem mass tag (TMT)-based quantitative proteomic analysis of proteins from peripheral and central nervous system compartments.Methods: We performed comparative proteomic analyses of plasma collected from AD patients and cognitively normal subjects. In addition, proteomic profiles from the inferior frontal cortex, superior frontal cortex, and cerebellum of postmortem brain tissue from five AD patients and five non-AD controls were compared with plasma proteomic profiles to search for common biomarkers. Liquid chromatography-mass spectrometry was used to analyze plasma and brain tissue labeled with isobaric TMT for relative protein quantification.Results: Our results showed that the proteins in complement coagulation cascade and interleukin-6 signaling were significantly altered in both plasma and brains of AD patients.Conclusion: Our results demonstrate the relevance in immune responses between the peripheral and central nervous systems. Those differentially regulated plasma proteins are explored as candidate biomarker profiles that illustrate chronic neuroinflammation in brains of AD patients. [ABSTRACT FROM AUTHOR]