Citations

Abstract Background Individuals with preclinical AD are difficult to detect using traditional clinical tools. Yet, many individuals classified as cognitively unimpaired (CU) can exhibit a heterogeneous pattern of subtle clinical abnormalities, potentially linked to early Alzheimer's disease (AD). Primary care providers often have access only to clinical tests to study at‐risk community‐dwelling older adults who visit them without cognitive complaints. Since early intervention is crucial in AD, identifying clinical tools to detect preclinical AD is important in areas with limited access to blood or imaging biomarkers. In this study, we evaluate the link between Montreal Cognitive Assessment (MoCA) total scores and AD pathology in CU individuals. Methods We studied 204 cognitively unimpaired (CU) older adults who underwent both 18 F‐FTP and 18 F‐MK6240 scans. These individuals were stratified based on their amyloid PET status, determined by visual reading, into CU A+ ( n = 35) and CU A‐ ( n = 137), as part of the ongoing HEAD study. CU adults had Clinical Dementia Rating (CDR) of 0 and were clinically identified as non‐MCI and non‐demented. Voxel‐wise linear regression models tested the association between MoCA total scores and tau pathology. Results CU A+T+ had significantly lower total MoCA scores than A‐T‐ individuals (Figure 1). Lesser MoCA total score was significantly associated with greater mediobasal temporal tau deposition, using both 18 F‐MK6240 and 18 F‐FTP [Figure 2]. When we separated the population by Aβ status, we found that these results were driven by the CU A+ group (Figure 3A) and were not present in CU A‐ individuals (Figure 3B). Discussion These findings indicate that the MoCA, a simple routine in‐office clinical test, can detect subtle cognitive dysfunction associated with preclinical AD. This suggests that simple cognitive testing can play a role in the early detection of AD and therefore an option for prescreening older adults in non‐specialized clinical settings, the initial interface for most older adults without cognitive complaints. Conclusion MoCA total, the common dementia screening test also plays a valuable role in detecting preclinical AD.

Abstract Background Prion diseases are universally fatal causes of rapid progressive dementia owing to the formation and spread of prions throughout the brain. Palliative care focuses on improving quality of life for patients with serious or advanced medical conditions. Timely access to palliative care is central to the care of patients with prion disease and other progressive neurodegenerative diseases. We sought to evaluate palliative care utilization and mode of delivery in patients with prion disease. Method Clinical data were extracted from the electronic medical records of patients with definite or probable prion disease diagnosed and managed across the Mayo Clinic Enterprise from January 2012 to August 2023. We systematically evaluated the frequency of symptoms and signs likely to benefit from palliative care and considered the relationship between these features and palliative care resource utilization, method of delivery, and outcomes. Result 172 patients with symptomatic prion disease were identified. 165 (94.8%) patients experienced ≥1 symptom/sign likely to benefit from palliative care, yet only 113 (65.7%) patients accessed palliative care resources during the illness course (hospice care: 39.7%; palliative care consultation: 14.9% inpatient, 6.9% outpatient; both: 3.4%). Lack of referral by the diagnosing clinician was the most common reason (55.9%) patients did not receive palliative care services. Early and predominant language dysfunction, behavioral changes, constipation, and emergency department visits or hospital admissions were independently associated with greater odds of referral for palliative care services. Goals of care (i.e., living environment, nutritional and hospitalization plans) and advanced care plans (i.e., healthcare surrogates, living will, code status, hospice) were more likely to be documented in patients receiving palliative care consultations (88.6% and 93.2%, respectively) versus hospice care alone (7.8% and 14.5%, respectively; p <0.001). Conclusion More than a third of patients with prion disease did not receive palliative care resources despite a high prevalence of symptoms/signs likely to benefit from palliative care. These findings highlight an opportunity to enhance the care of patients with prion disease by promoting early access to palliative care resources that may support symptom management, enhance caregiver support, and reinforce patient autonomy by clarifying goals of care and advance care planning.

ABSTRACT Background Mood episodes in bipolar disorder (BD) follow a seasonal pattern in approximately 25% of patients. We aimed to examine the associations of specific seasonality patterns in BD with various clinical phenotypes and treatment‐related outcomes. Methods Patients from the Mayo Clinic Bipolar Disorder Biobank with available seasonality data were included in the study. Among those reporting any seasonality, participants were further categorized into four seasonality groups: fall/winter depression, spring/summer (hypo)mania, biphasic (fall/winter depression with spring/summer (hypo)mania), and equinoctial seasonality (any mood episode occurring in spring or fall). Regression models were used, treating seasonality patterns as the predictor of clinical phenotypes (BD subtype, early onset, history of psychosis, suicide attempt, rapid cycling), lifetime medication exposure (number of unique antidepressants, antipsychotics, and any psychotropics) and treatment response to mood stabilizers (Alda A score). Results Among 1702 patients with BD (61.5% female, mean age = 41.43 ± 14.73 years), 44.6% reported seasonal mood episodes. Individuals with any seasonality were more likely to have BD‐I (OR = 1.29, p = 0.024), early onset (OR = 1.29, p = 0.026), exposure to higher lifetime number of antipsychotics (IRR = 1.20, p < 0.001) and any psychotropics (IRR = 1.13, p < 0.001). Fall/winter depression was associated with a higher lifetime number of antidepressants (IRR = 1.18, p = 0.021), any psychotropics (IRR = 1.14, p = 0.013), worse response to lithium ( β = −0.82, p = 0.029) and all mood stabilizers ( β = −0.69, p = 0.014). Spring/summer (hypo)mania showed negative associations with rapid cycling (OR = 0.36, p < 0.001) and lifetime number of antidepressants (IRR = 0.70, p = 0.013). Equinoctial seasonality was linked to a history of psychosis (OR = 1.76, p = 0.004). Conclusion Seasonality in BD is associated with distinct clinical features and treatment‐related outcomes. Specific seasonality patterns, particularly fall/winter depression, may reflect a more complex and difficult‐to‐treat illness course. These findings highlight the need for research to better characterize seasonality subtypes beyond a binary “seasonal” vs. “non‐seasonal” classification and to explore how these patterns influence the illness course and management of BD.

Abstract Background Prior studies of Alzheimer's disease (AD) biomarker disclosure have answered important questions about individuals’ experiences learning amyloid results. In comparison, the experiences of individuals performing AD biomarker disclosure have been under characterized. The present study examines the clinician experience disclosing amyloid positron emission tomography (PET) results within the Alzheimer's Disease Neuroimaging Initiative's ADNI‐4 study. Methods The ADNI‐4 longitudinal cohort study includes a pragmatic process for amyloid PET disclosure for participants across the cognitive spectrum. Disclosing clinicians complete a short questionnaire after each disclosure session, reporting on the visit length, the clinician's rating of participant and study partner understanding and emotional reactions, topics discussed, challenges, assessment of the visit overall, and any feedback about the process. Results Across the first 100 disclosures (48 cognitively normal, 35 Mild Cognitive Impairment (MCI), 17 dementia) in ADNI‐4, visits lasted an average of 29.4 minutes (SD 13.9, range 10‐90). Most cognitively impaired participants had a loved one present at the disclosure visit (dementia 94%, MCI 80%) but the majority of cognitively normal participants (73%) did not. Clinicians rated understanding of the result as adequate for all study partners and the vast majority (94%) of participants. Clinicians reported feeling “very confident” in their ability to assess readiness to receive result (70%), disclose (73%), and answer questions (77%). Clinicians rated all visits as “good” or better, with two‐thirds (65%) rated as “excellent.” Frequently discussed topics included meaning of result (99%), other risk factors (72%), and emotional impact of result (49%). Stigma and discrimination were rarely discussed, coming up in 12% and 3% of disclosure sessions, respectively. Challenges were infrequent (7%) and primarily included desire for additional information and challenges related to the participant's impairment. Clinicians provided the study team feedback about the disclosure process for 25% of disclosure visits. Comments included the desire for additional information or resources, positive feedback, and the importance of the study partner. Conclusions Clinicians disclosing amyloid PET results in ADNI‐4 report high confidence, adequate participant and study partner understanding, and few challenges. These data from clinicians, in combination with participant data, will inform future disclosure practices in both research and care.

Abstract Background Despite recent approval of monoclonal antibodies that reduce amyloid (Ab) accumulation, the development of disease‐modifying strategies targeting the underlying mechanisms of Alzheimer’s Disease (AD) are urgently needed. We identified mitochondrial complex I (mtCI) as a small‐molecule druggable target for AD. Using cryo‐EM, we previously demonstrated that the neuroprotective tool compound CP2 directly binds to the Q‐site of mtCI and weakly inhibits its activity. Method Rational design and extensive structure‐activity relationship studies using CP2 as a tool compound allowed the development of novel classes of partial mtCI inhibitors with high selectivity, specificity, safety, and improved drug‐like properties. Target engagement, selectivity, efficacy, safety and the direct binding to mtCI were demonstrated using multiple in vitro assays. Efficacy in vivo was established using APP/PS1 mice. The best new leads, C458 and C273, were evaluated as preclinical candidates. Result Like CP2, C458 and C273 weakly inhibit mtCI, leading to AMPK activation, which triggers a neuroprotective stress response. This response enhances oxidative stress protection, promotes autophagy, and increases mitochondrial biogenesis and turnover, ultimately protecting against Aβ toxicity. Pretreatment with the irreversible mtCI inhibitor rotenone (at non‐toxic concentrations) blocked C458 and C273 from binding to mtCI and abrogated their protection against Aβ toxicity. Both C458 and C273 exhibited excellent bioavailability, blood–brain barrier penetrance, and a clean safety profile in the CEREP 44 safety panel. Chronic administration of C458 (25 mg/kg/day in drinking water ad lib ) to APP/PS1 mice for 7 months preserved cognition, improved long‐term potentiation, reduced oxidative stress and inflammation, and enhanced mitochondrial biogenesis. Similarly, C273 (20, 50, or 80 mg/kg/day) administered to C57BL/6 mice for one month showed no detectable side effects or toxicity in the heart or liver. Conclusion Mechanistic studies revealed that C458 and C273 activate a mitochondrial stress response, augmenting mitochondrial biogenesis, antioxidant signaling, and autophagy, which collectively provided protection against Aβ toxicity in multiple in vitro and in vivo models of AD. These findings demonstrate that weak mtCI inhibition by novel compounds C458 and C273, with improved drug‐like properties, is neuroprotective. This supports the feasibility of developing safe and efficacious mtCI inhibitors as a disease‐modifying strategy for AD.

ABSTRACT Cytotoxic T lymphocytes (CTLs) are known to eliminate target cells through perforin-mediated, contact-dependent killing - a process limited by the number of effector T cells despite its serial nature. CTLs likely also possess a mass killing mechanism that can eliminate target cells more efficiently. Using CAR-T cells against B7H3 present on B16 tumor targets, we demonstrate that activated T cells can also kill targets in a perforin-independent manner by releasing diffusible TNF and IFNγ capable of killing nearby targets in a paracrine fashion even if they bear no antigen. Against an unperturbed target, paracrine killing is inefficient but is enhanced by the deletion of TNFR1 signaling molecules such as TAK1, HOIP, or TBK1/IKKε. Notably, these molecules are inhibited naturally by pathogen-encoded antagonists. Expression of a microbial-encoded antagonist, such as the Yersinia -encoded YopJ that antagonizes TAK1 or Ebola-encoded VP35 that antagonizes TBK1/IKKε, alters the target cell response to these cytokines from non-lethal to lethal. We propose that target cells are inherently resistant to killing by TNF and IFNγ, but the presence of a microbial factor alters this sensitivity, providing for the selective elimination of the infected cell while minimizing harm to uninfected bystander cells. We propose the term ‘pathogen-restriction’ to describe this discriminatory mechanism. Potentially, any microbial-derived factor that crosstalks with the TNF and IFNγ signaling pathways can function as a pathogen-restriction element. GRAPHICAL ABSTRACT Short Summary T cells use TNF and IFNγ to kill target cells in a paracrine manner where target elimination is restricted by the presence of pathogen-derived factors.

Abstract Background Alzheimer Disease (AD) pathology evolves over decades, and understanding this progression is critical to the understanding of the disease and timing therapeutic interventions. Since individuals with Autosomal Dominant AD (ADAD) develop symptoms around the same age as their parent, it is possible to predict symptom onset and stage individuals by their estimated years to symptom onset (EYO). This approach does not generalize to other forms of AD, thus there is a pressing need for the timecourse of ADAD to be defined in broadly relevant terms. The objective of this project is to validate the Sampled Iterative Local Approximation (SILA) algorithm in a cohort with a known disease timecourse. SILA generates an estimate of time from amyloid positivity (A time ) based on longitudinal PET data. Method We evaluated A time in a longitudinal ADAD sample ( N = 316) with PET PiB data in three ways. First, we compared predicted age at amyloid positive (A+) to observed age at A+ for individuals who became A+ during enrollment. Next, using linear regression, we compared estimated age at A+ to estimated age at symptom onset (EYO=0). Finally, we used generalized additive models to compare the amount of variance in concurrent cognitive performance explained both A time and EYO. Result We observed a mean average error of 1.15 years between actual age at A+ ( N = 26) and the SILA‐predicted A time . Across all participants, SILA‐estimated age at A+ explained 39% of the variance in estimated age at symptom onset ( β = 0.918, p < 0.0001). Finally, we observed a nonlinear association between cognition and both A time and EYO. A time explained 19% of the variance in the general cognitive composite while EYO explained 43% of the variance. Conclusion SILA produces a valid estimate of time‐from‐amyloid positivity in ADAD. This work allows for disease stage in ADAD to be compared to staging for broad forms of AD, which was not previously possible using EYO. However, this work also illustrates that there is a high degree of heterogeneity in preclinical disease duration that is not explained by amyloid alone.

Abstract How embryonic cells generate large clones of cells in the adult represents a fundamental question in biology. Here using melanocyte stem cells (McSCs) in the zebrafish as a model we explore the function of the master melanocyte transcription factor (MITF) in safeguarding McSCs in embryonic development and their potential to pigment large clones in the adult. MITF is well known is for its role in the specification of melanoblasts from the neural crest (NC) and their differentiation into melanocytes, yet little is known about how this activity shapes the stem cell lineages. Here, we use live imaging coupled with single-cell transcriptomics and lineage tracing to show that MITF ( mitfa in zebrafish) protects the melanocyte stem cell (McSC) fate in zebrafish. Utilizing a temperature sensitive mitfa vc7 mutant, we show that loss of Mitfa activity leads to a surprising premature and aberrant expansion of McSC progeny at the niche during embryogenesis, coupled with novel emergent transcriptional cell states. Linage tracing of McSCs from the embryonic to juvenile stages reveals Mitfa activity is subsequently required in regeneration by Schwann cell-like and melanocyte stem cell progenitors that serve as a reservoir for fast-responding pigment progenitors. Thus, the impact of Mitfa loss on the melanocyte lineage is cell-state and stage-specific. The emergent cell states resulting from mitfa loss may have important implications for understanding how reduced MITF activity contributes to human genetic disease and melanoma.

Abstract Background Frontotemporal dementia (FTD) is a neurodegenerative disorder marked by early impairments in executive function and altered prefrontal neural circuitry. These traits are also observed in Attention Deficit Disorder (ADD) and Attention Deficit Hyperactivity Disorder (ADHD), suggesting the possibility of shared mechanisms and a role for developmental neurocognitive factors in the onset of FTD. High‐penetrance mutations in GRN, C9orf72, and MAPT increase FTD risk and are suspected to influence neurodevelopment. This study hypothesizes that pre‐symptomatic carriers of these mutations exhibit cognitive and behavioral traits that overlap with those observed in ADD/ADHD. Method This cross‐sectional study analyzed participants from the ARTFL‐LEFFTDS Longitudinal FTLD (ALLFTD) Study. Inclusion criteria restricted the sample to mutation carriers with pathogenic variants in GRN, C9orf72, or MAPT while excluding individuals with prior psychiatric diagnoses (e.g., bipolar disorder, major depressive disorder) and those taking antipsychotic or anxiolytic medications to avoid potential confounding effects on test validity and interpretation. The final sample included N = 338 participants, categorized as pre‐symptomatic mutation carriers ( N = 227) or asymptomatic noncarriers ( N = 111). To assess potential overlaps with ADD/ADHD traits, a targeted subset of measures reflecting executive function, working memory, attention, social behavior, and hyperactivity were extracted from validated cognitive and neuropsychiatric assessments. Mutation carriers were further classified as either converters ( N = 20) who progressed to symptomatic FTD (CDR ≥ 1) or non‐converters ( N = 95) who remained asymptomatic. Only pre‐conversion scores were analyzed for converters. Group comparisons were conducted using general linear models adjusted for age and sex. Result Pre‐symptomatic mutation carriers showed significantly lower verbal fluency ( p = 0.004) and a trend toward reduced working memory ( p = 0.05) compared to noncarriers. Converters exhibited poorer overall cognitive performance ( p <0.0001), verbal fluency ( p = 0.001), and memory and attention ( p = 0.04) compared to non‐converters. Converters demonstrated higher Neuropsychiatric Inventory scores ( p = 0.0001), particularly in hyperactivity ( p = 0.003), reflecting greater behavioral disturbances. Conclusion Baseline impairments in cognitive function, memory, and neuropsychiatric profiles distinguish converters from non‐converters, highlighting overlaps between ADD/ADHD traits and prodromal FTD. These findings suggest shared neurobiological mechanisms and underscore the need for mutation‐specific studies to further explore the neurodevelopmental factors driving FTD progression.

We describe an unusual case of a woman in her 30s who had recently undergone Roux-en-Y gastric bypass and presented to the emergency department with a 6-week history of intractable nausea and vomiting, accompanied by progressively worsening bilateral leg weakness. Examination revealed persistent upbeat nystagmus, paraparesis, areflexia in the lower extremities, brisk reflexes in the upper extremities and diminished sensation across all modalities in lower limbs. Brain and spine MRIs were unremarkable, there was no nerve root enhancement. Laboratory tests revealed thiamine deficiency, with a level of 28 nmol/L (reference range: 70–108 nmol/L). No gangliocyte antibodies were detected. Cerebrospinal fluid study showed no albuminocytological dissociation. Electrodiagnostic studies showed evidence of lumbosacral polyradiculopathy. The patient was eventually diagnosed with thiamine deficiency-related acute nutritional axonal neuropathy and Wernicke’s encephalopathy. After aggressive thiamine supplementation and 8 weeks of physical rehabilitation, her leg strength improved, but she still requires assistance to ambulate.