Amanda Heslegrave

Background and ObjectivesBlood-based biomarkers are strongly correlated with amyloid positivity in research settings, but their long-term performance in heterogeneous populations remains unclear. O...

1. An aging population globally means we are now seeing a heightened prevalence of age-related neurodegenerative diseases such as Alzheimer’s Disease (AD) [1]. The subsequent development of drug tr...

Background Autosomal dominant Alzheimer’s disease (ADAD) serves as a model for presymptomatic biomarker discovery. Characterising the temporal profile of plasma biomarker levels in presymptomatic individuals may enhance understanding of disease pathogenesis, inform future clinical trials and guide clinical interpretation. Methods We evaluated 124 proteins using a NUcleic acid-Linked Immuno-Sandwich Assay panel in 270 plasma samples from a longitudinal cohort study of ADAD, comprising 113 individuals (73 mutation carriers and 40 non-carriers). We determined the plasma proteomic changes that distinguished mutation carriers from non-carriers. We then used predicted age at symptom onset to determine the approximate timing of presymptomatic divergence in biomarker levels in carriers relative to non-carriers. Results Nine proteins (amyloid-beta 42 (Aβ42), beta-secretase 1 (BACE1), glial fibrillary acidic protein (GFAP), pTau181, pTau231, pTau217, t0tal tau (MAPT), neurofilament light (NfL) and acetylcholinesterase (AChE)) robustly differed between carriers and non-carriers cross-sectionally. Longitudinal analyses showed elevated Aβ42 levels were statistically discernible in carriers approximately 26 years before expected symptom onset. Carriers diverged from non-carriers in phosphorylated tau markers at approximately 21–24 years before expected symptom onset, total tau at 19 years, GFAP and BACE1 at 14 years and NfL at 6 years. Differences in AChE were seen in symptomatic individuals likely reflecting cholinesterase inhibitor use. Conclusion Multiple plasma proteins are elevated in presymptomatic and symptomatic ADAD mutation carriers relative to non-carriers. Changes in eight biomarkers occur sequentially from 26 to 6 years prior to symptom onset. Combining biomarkers may help in staging presymptomatic AD and optimise clinical trial inclusion. Further work is needed to assess how these findings generalise to non-monogenic AD.

The Dementia Trials Accelerator (DTA) is a UK-wide programme designed to improve the feasibility, efficiency, and inclusiveness of recruitment into clinical trials of dementia and related brain-health conditions. Dementia trials are frequently constrained by the difficulty and cost of identifying eligible participants, which often requires cognitive assessments and measurement of blood-based biomarkers. The DTA addresses these barriers with two linked services. First, the DTA provides a federated platform to improve findability of potential participants across existing UK-based cohorts with consent to recontact. A single point of contact across multiple cohorts would allow increased efficiency of search for participants for studies. Second, the DTA provides a community-centred pre-screening service with information relevant to trial eligibility and a linked plasma and DNA tissue bank, with participant consent for recontact. Participants aged 65-75 years are approached via existing cohorts and registries. Consenting participants complete an online questionnaire and digital cognitive assessment, attend an in-person assessment for physical measures and face-to-face cognitive testing, and provide venous blood samples which are processed to plasma and whole blood for long-term storage and biomarker measurement. The initial programme target is to recruit at least 10,000 participants into the DTA pre-screening service. The DTA is designed to support approved academic and industry studies by enabling the DTA team to approach eligible participants for specific studies, without transferring identifiable information without consent. In parallel with its immediate trial-readiness purpose, the DTA is positioned to interoperate with emerging national approaches to biomarker-led recruitment by generating high-quality, recontactable cohorts with standardised cognitive characterisation and scalable biosampling suitable for blood-based biomarkers.

Background and ObjectivesPrion diseases can mimic Alzheimer disease (AD) at presentation. Alzheimer's Association AD diagnostic criteria suggest that a single abnormal highly specific plasma biomar...

Dementia with Lewy Bodies (DLB) is the most common neurodegenerative dementia after Alzheimer’s disease (AD), but it remains challenging to diagnose due to overlapping symptoms and mixed pathologies. This pilot study tested whether DLB has different metabolic blood proteomic profiles compared to AD and controls. Serum was analysed from people with DLB (n = 20), a group with AD (either with Alzheimer’s disease dementia or Mild Cognitive Impairment with a positive amyloid positron emission tomography scan (MCI+/AD) (n = 15), and similarly aged controls (n = 15) using the Olink Metabolism panel encompassing 92 proteins. Six proteins (PILRB, LRIG1, NECTIN2, TINAGL1, SSC4D, and FKBP4) were significantly different in DLB compared with the controls, and one protein (SERPINB8) was differentially expressed when compared with MCI+/AD. Receiver operating characteristic curves for biologically relevant proteins that have previously established roles in neurodegenerative and cognitive properties showed that RNASE3 levels could differentiate DLB from MCI+/AD (area under the curve (AUC) = 0.717, sensitivity = 0.850, and specificity = 0.600). A multimarker model incorporating RNASE3 with phosphorylated tau 217 (pTau217) and polygenic risk scores for LBD achieved improved accuracy in discriminating DLB from MCI+/AD (AUC = 0.963, sensitivity = 1.000, and specificity = 0.900). Pathway analyses revealed dysregulation in cortisol signalling, inflammation resolution, and ErbB4-mediated neuroplasticity, which point towards peripheral protein alterations related to the adaptation to stress, immune regulation, and synaptic integrity in DLB. The present exploratory study highlights potential pathophysiological mechanisms implicated in DLB, suggesting that a multimodal biomarker panel may perform better compared to single proteins. Considering the small sample sizes, the findings will need to be replicated in larger cohorts.

Background Childhood neurodegenerative disorders are usually rare, genetic, and life-limiting. Whilst targeted approaches present huge potential, significant hurdles include disease rarity, geographical dispersion of patients, funding, clinical trial design, and execution. Crucially, the paucity of robust biomarkers and objective measures of disease progression hampers evaluation of efficacy, drug development and regulatory approval. To address this paradigm, we developed a Multimodal Multiomics Machine Learning (MMM) framework, integrating large-scale, multi-source patient datasets to generate quantitative metrics for disease stratification and longitudinal tracking. We applied MMM to PLA2G6-associated neurodegeneration (PLAN), an ultra-rare condition currently lacking validated biomarkers, where precision gene therapy approaches are at an advanced preclinical stage. Methods A large, single time-point international natural history study (n = 310) was conducted alongside development of a disease-specific rating scale (CoPLAN-DRS), prospective longitudinal neuroimaging, and multiomic biomarker discovery. Machine learning methods were applied to the integrated dataset. Results Kaplan-Meier analyses enabled estimates for survival and time to loss of ambulation. Multiple clinical, radiological, and biofluid biomarkers were identified, clearly correlating with disease progression. The CoPLAN-DRS and brain MRI Quantitative Susceptibility Mapping showed strong positive correlation with age (rho = 0.69, 0.96 respectively). Nicastrin, a critical structural component of the gamma-secretase complex in Amyloid Precursor Protein (APP) processing, was identified as a novel biomarker. Neurofilament light levels showed strong negative correlation with disease progression (rho = -0.74). The complex multi-dimensional dataset was distilled into a simplified, clinically intuitive Digital Disease Dashboard (DDD), enabling real-time visualisation of disease severity. Conclusions Our study highlights the clinical utility of MMM in integrating multi-dimensional data from rare disease cohorts, delivering an unbiased, data-driven, optimised biomarker set. Condensing this into the DDD provides a pragmatically useful tool for clinicians, facilitating longitudinal tracking of disease. The MMM and DDD have accelerated clinical-trial readiness for PLAN, and potentially applicable to a broad range of neurogenetic disorders.

Charcot-Marie-Tooth disease type 2D (CMT2D) results from gain-of-function mutations in GARS1 , which encodes glycyl-tRNA synthetase (GlyRS), the enzyme responsible for charging transfer RNA (tRNA) with glycine. There are several CMT2D mouse models, but Gars ^{Δ ETAQ /+} is the only one that bears a patient-sourced mutation. Created using CRISPR/Cas9 to model a 12-nucleotide de novo GARS1 deletion identified in an unusually severe CMT2D patient, Gars ^{Δ ETAQ /+} mice have previously been shown to display several neuromuscular phenotypes; motor axon loss, denervated neuromuscular junctions (NMJs) and reduced muscle function. Here, we extend these analyses to provide a more comprehensive understanding of both motor and sensory nerve deficits across hind- and fore-limbs. At 3 months, Gars ^{Δ ETAQ /+} mice possess sex-independent alterations in the levels of neuropathy biomarkers – including decreased NfL and increased periaxin – alongside reduced muscle endurance and strength, and impairments in the sensory modalities of mechanosensation, proprioception and nociception. Underpinning these dysfunctions, we identified site-specific defects comprising altered sensory neuron populations, muscle spindle loss, reduced motor neuron size, disrupted NMJ innervation and maturation, and reduced axonal transport of signalling endosomes in vivo . Together, these experiments show that Gars ^{Δ ETAQ /+} mice display robust and selective peripheral nerve pathology that manifests in a general distal-to-proximal fashion, priming this CMT2D allele for testing treatments and evaluating mechanisms underlying peripheral nerve vulnerability. Abstract Figure:

Background: Autosomal dominant Alzheimer’s disease (ADAD) serves as a model for presymptomatic biomarker discovery. Characterising the temporal profile of plasma biomarker levels in presymptomatic individuals may enhance understanding of disease pathogenesis, inform future clinical trials, and guide clinical interpretation. Methods: We evaluated 124 proteins using a NUcleic acid-Linked Immuno-Sandwich Assay (NULISA) panel in 270 plasma samples from a longitudinal cohort study of ADAD, comprising 113 individuals (73 mutation carriers and 40 non-carriers). We determined the plasma proteomic changes that distinguished mutation carriers from non-carriers. We then used predicted age at symptom onset to determine the approximate timing of presymptomatic divergence in biomarker levels in carriers relative to non-carriers. Results: Nine proteins (Aβ42, BACE1, GFAP, pTau181, pTau231, pTau217, MAPT, NfL, and AChE) robustly differed between carriers and non-carriers, cross-sectionally. Longitudinal analyses showed Aβ42 levels were elevated in carriers at least 26 years before expected symptom onset. Carriers diverged from non-carriers in phosphorylated tau markers at 21-24 years before expected symptoms, total-tau at 19 years, GFAP and BACE1 at 14 years, and NfL at 6 years. Differences in AChE were seen in symptomatic individuals, likely reflecting cholinesterase inhibitor use. Conclusion: Multiple plasma proteins are elevated in presymptomatic and symptomatic autosomal dominant AD mutation carriers relative to non-carriers. Changes in eight biomarkers occur sequentially from 26 to 6 years prior to symptom onset. Combining biomarkers may help in staging presymptomatic AD and optimise clinical trial inclusion. Further work is needed to assess how these findings generalise to non-monogenic AD. What is already known on this topic: The molecular pathology of Alzheimer’s disease develops many years before the onset of symptoms, and multiple plasma biomarkers of Alzheimer’s pathology have been identified. Understanding the timing of biomarker abnormality is important to guide trial design for the timing of interventions to prevent the onset of dementia. What this study adds: Using an autosomal dominant Alzheimer’s disease cohort, we identify multiple plasma biomarkers that distinguish mutation carriers from non-carrier familial controls and characterise the timing of these changes relative to symptom onset. We demonstrate that biomarkers show change many years before symptom onset: markers of abnormal tau phosphorylation more than 20 years prior, followed by markers of reactive astrocytosis and synaptic dysfunction approximately 15 years prior, and neurodegenerative markers within 10 years of symptoms. How this study might affect research, practice or policy: Plasma biomarkers could be used in pre-clinical autosomal dominant Alzheimer’s disease to chart disease trajectories and predict symptom onset, allowing targeted disease-modifying therapy implementation and optimised clinical trial design.

Neuronal ceroid lipofuscinosis type 1 (CLN1) is a rare autosomal recessive lysosomal storage disorder caused by pathogenic variants in the PPT1 gene, leading to lipofuscin accumulation, neurodegeneration, psychomotor regression, seizures, and vision loss, with early death in infancy. Currently, no curative treatment exists. Neuroinflammation plays a major role in CLN1 pathophysiology, making anti-inflammatory treatments a potential option. Fingolimod, an immune modulator approved for multiple sclerosis (MS), has shown efficacy in reducing neurodegeneration in CLN1 mouse models. Neurofilament light chain (NfL), a key axonal structural protein, is a biomarker of neuronal damage, with elevated levels indicating axonal injury in various neurologic diseases. We report on 2 pediatric patients with CLN1 treated with fingolimod to assess clinical response and its impact on NfL levels. This study involved 2 patients with CLN1 who were treated with fingolimod under a compassionate use program at Great Ormond Street Hospital. Inclusion criteria required a molecular diagnosis of CLN1. Patient 1 was monitored over a 36-month period, while patient 2 was followed for 15 months. Fingolimod was administered daily, with dosing adjusted based on age and weight. Lymphocyte counts and NfL levels were regularly measured throughout the study to assess treatment response. The primary outcome was the evaluation of the safety profile following the SOP for fingolimod administration at GOSH. Secondary outcomes included clinical assessments to monitor disease progression and lymphocyte count. As an exploratory outcome, we measured NfL levels, which serve as a biomarker of neuroinflammation and axonal injury. Two patients with CLN1 were treated with fingolimod under compassionate use. Patient 1 showed a >50% reduction in NfL levels after 14 months, approaching normal results after 2 years, while patient 2 had limited NfL data but generally lower levels, possibly due to later disease onset. No major safety concerns were observed. No clinical improvements were seen, although some stabilization was observed despite expected disease progression. The significant reduction in NfL levels observed suggests reduced neuroaxonal damage secondary to immune modulation. This finding highlights the potential role of immune modulation in addressing underlying inflammatory processes in CLN1, even if it does not fully halt disease progression.