A pilot study to investigate the safety and feasibility of antiretroviral therapy for Alzheimer's disease (ART-AD).

Retrotransposons are viral-like DNA sequences that constitute approximately 41% of the human genome. Studies in Drosophila, mice, cultured cells, and human brain indicate that retrotransposons are activated in settings of tauopathy, including Alzheimer's disease, and causally drive neurodegeneration. The anti-retroviral medication 3TC (lamivudine), a nucleoside analog reverse transcriptase inhibitor, limits retrotransposon activation and suppresses neurodegeneration in tau transgenic Drosophila, two mouse models of tauopathy, and in brain assembloids derived from patients with sporadic Alzheimer's disease. We performed a 24-week phase 2a open-label clinical trial of 300 mg daily oral 3TC (NCT04552795) in 12 participants aged 52-83 years with a diagnosis of mild cognitive impairment due to suspected Alzheimer's disease. Primary outcomes included feasibility, blood brain barrier penetration, effects of 3TC on reverse transcriptase activity in the periphery, and safety. Secondary outcomes included changes in cognition and fluid-based biomarkers of neurodegeneration and neuroinflammation. All participants completed the six-month trial; one event of gastrointestinal bleeding due to a peptic ulcer was reported. 3TC was detected in blood and cerebrospinal fluid (CSF) of all participants, suggestive of adherence to study drug and effective brain penetration. Cognitive measures remained stable throughout the study. Glial fibrillary acidic protein (GFAP) (P=0.03) and Flt1 (P=0.05) were significantly reduced in CSF over the treatment period; Aß42/40 (P=0.009) and IL-15 (P=0.006) were significantly elevated in plasma. While this is an open label study of small sample size, the significant decrease of some neurodegeneration- and neuroinflammation-related biomarkers in CSF, significantly elevated levels of plasma Aß42/40, and a trending decrease of CSF NfL after six months of 3TC exposure suggest a beneficial effect on subjects with mild cognitive impairment due to suspected Alzheimer's disease. Feasibility, safety, tolerability, and central nervous system (CNS) penetration assessments further support clinical evaluation of 3TC in a larger placebo-controlled, multi-dose clinical trial.

Demographic, clinical, biomarker, and neuropathological correlates of posterior cortical atrophy: an international cohort study and individual participant data meta-analysis.

BACKGROUND: Posterior cortical atrophy is a rare syndrome characterised by early, prominent, and progressive impairment in visuoperceptual and visuospatial processing. The disorder has been associated with underlying neuropathological features of Alzheimer's disease, but large-scale biomarker and neuropathological studies are scarce. We aimed to describe demographic, clinical, biomarker, and neuropathological correlates of posterior cortical atrophy in a large international cohort. METHODS: We searched PubMed between database inception and Aug 1, 2021, for all published research studies on posterior cortical atrophy and related terms. We identified research centres from these studies and requested deidentified, individual participant data (published and unpublished) that had been obtained at the first diagnostic visit from the corresponding authors of the studies or heads of the research centres. Inclusion criteria were a clinical diagnosis of posterior cortical atrophy as defined by the local centre and availability of Alzheimer's disease biomarkers (PET or CSF), or a diagnosis made at autopsy. Not all individuals with posterior cortical atrophy fulfilled consensus criteria, being diagnosed using centre-specific procedures or before development of consensus criteria. We obtained demographic, clinical, biofluid, neuroimaging, and neuropathological data. Mean values for continuous variables were combined using the inverse variance meta-analysis method; only research centres with more than one participant for a variable were included. Pooled proportions were calculated for binary variables using a restricted maximum likelihood model. Heterogeneity was quantified using I2. FINDINGS: We identified 55 research centres from 1353 papers, with 29 centres responding to our request. An additional seven centres were recruited by advertising via the Alzheimer's Association. We obtained data for 1092 individuals who were evaluated at 36 research centres in 16 countries, the other sites having not responded to our initial invitation to participate to the study. Mean age at symptom onset was 59·4 years (95% CI 58·9-59·8; I2=77%), 60% (56-64; I2=35%) were women, and 80% (72-89; I2=98%) presented with posterior cortical atrophy pure syndrome. Amyloid ß in CSF (536 participants from 28 centres) was positive in 81% (95% CI 75-87; I2=78%), whereas phosphorylated tau in CSF (503 participants from 29 centres) was positive in 65% (56-75; I2=87%). Amyloid-PET (299 participants from 24 centres) was positive in 94% (95% CI 90-97; I2=15%), whereas tau-PET (170 participants from 13 centres) was positive in 97% (93-100; I2=12%). At autopsy (145 participants from 13 centres), the most frequent neuropathological diagnosis was Alzheimer's disease (94%, 95% CI 90-97; I2=0%), with common co-pathologies of cerebral amyloid angiopathy (71%, 54-88; I2=89%), Lewy body disease (44%, 25-62; I2=77%), and cerebrovascular injury (42%, 24-60; I2=88%). INTERPRETATION: These data indicate that posterior cortical atrophy typically presents as a pure, young-onset dementia syndrome that is highly specific for underlying Alzheimer's disease pathology. Further work is needed to understand what drives cognitive vulnerability and progression rates by investigating the contribution of sex, genetics, premorbid cognitive strengths and weaknesses, and brain network integrity. FUNDING: None.

Primary progressive aphasia and amyotrophic lateral sclerosis (PPA-ALS): A longitudinal case study.

OBJECTIVE: Approximately 50% of patients with amyotrophic lateral sclerosis (ALS) experience cognitive decline, with frontotemporal dementia (FTD) accounting for up to 15% of these cases. Despite this, there is considerable delay in diagnosis, which affects patient care. METHODS: We report longitudinal results of neuropsychological evaluations in a patient diagnosed with non-fluent/agrammatic primary progressive aphasia (nfvPPA) and amyotrophic lateral sclerosis (ALS). The patient, Ms. X, presented with progressive speech difficulties starting in her late-60's. Initial diagnosis was nfvPPA. After 4-5 years of progressive swallowing difficulties, as well as facial weakness, her diagnosis was modified to PPA-ALS. RESULTS: Ms. X underwent neuropsychological evaluations three times over a period of five years. Results of evaluations were intact and stable over time, except for progressive loss of speech impacting her performance on a sentence repetition task. CONCLUSION: This case study provides valuable insight into the overlap between PPA-ALS from a neuropsychological standpoint. The results reflect preserved cognitive skills in the context of loss of speech and motor abilities. This case study also shows the length of time between onset of symptoms and clear diagnosis, which often requires an immense amount of health literacy and personal advocacy on the part of the patient.

Comprehensive Evaluation of the Functional Activities Questionnaire (FAQ) and Its Reliability and Validity.

The Functional Activities Questionnaire (FAQ) is a collateral-report measure of difficulties in activities of daily living. Despite its widespread use, psychometric analyses have been limited in scope, piecemeal across samples, and limited primarily to classical test theory. This article consolidated and expanded psychometric analyses using tools from generalizability and item response theories among 27,916 individuals from the National Alzheimer's Coordinating Center database who completed the FAQ. Reliability was evaluated with internal consistency, test-retest, and generalizability analyses. Validity was assessed via convergence with neurocognitive measures, classification accuracy with impairment stage, and confirmatory factor and item response theory analyses. Demographics did not impact scores and there was strong evidence for reliability (0.52-0.95), though coefficients were attenuated when restricted in range to diagnostic groups (e.g., normal cognition). There were strong correlations with neurocognitive measures (rs: -.30 to -.59), strong classification accuracy (areas under the curve: .81-.99), and a single-factor model had excellent fit. All items evidenced strong item response theory discrimination and provided significant information regarding functional disability, albeit within a relatively restricted range. The FAQ is a reliable and valid measure of activities of daily living concerns for use in clinical/research settings. It best assesses mild levels of functional difficulty, which is helpful in distinguishing normal cognition from mild cognitive impairment and dementia.

A Brief Overview of Tauopathy: Causes, Consequences, and Therapeutic Strategies.

There are currently no disease-modifying therapies for the treatment of tauopathies, a group of progressive neurodegenerative disorders that are pathologically defined by the presence of tau protein aggregates in the brain. Current challenges for the treatment of tauopathies include the inability to diagnose early and to confidently discriminate between distinct tauopathies in patients, alongside an incomplete understanding of the cellular mechanisms involved in pathogenic tau-induced neuronal death and dysfunction. In this review, we describe current diagnostic and therapeutic strategies, known drivers of pathogenic tau formation, recent contributions to our current mechanistic understanding of how pathogenic tau induces neuronal death, and potential diagnostic and therapeutic approaches.