Times are shown in your local time zone GMT
Ad-blocker Detected - Your browser has an ad-blocker enabled, please disable it to ensure your attendance is not impacted, such as CPD tracking (if relevant). For technical help, contact Support.
Scientific Session - Chemical - Alzheimer's Disease
Scientific
Scientific
1:30 pm
22 February 2025
Meeting Room 110
Discipline Streams
Chemical Pathology
Session Scientific Program
Colin Masters1
1The Florey, University of Melbourne
Late onset (sporadic) Alzheimer's disease: caused by defective innate immunity and treated with adaptive immunity.
The etiology of Alzheimer’s disease (AD) is best understood through the deposition of Aβ-amyloid (Aβ). There are two basic forms of AD. The common (>95%) form is sporadic, and is caused by the failure to clear Aβ (mean age at onset 80 years). The rare (< 5%) autosomal dominant familial form is caused by the over-production of Aβ42, also on a background of failure to clear (mean age at onset 45 years). In both forms, the kinetics of Aβ accumulation are similar, taking about 30 years to accumulate a total of approximately 7mg of Aβ. Thus we estimate that sporadic AD starts about the age of 50 years and the autosomal dominant form starts about 15 years of age. The first changes are seen in the Default Mode Network, a brain system that is used for high level coordination of the encoding of memories (the engram), which is the essential first step in learning. We now know that deficits of learning are more severe than memory in the early phases of AD. This may be related to the normal function of the APP molecule that gives rise to Aβ.
1The Florey, University of Melbourne
Late onset (sporadic) Alzheimer's disease: caused by defective innate immunity and treated with adaptive immunity.
The etiology of Alzheimer’s disease (AD) is best understood through the deposition of Aβ-amyloid (Aβ). There are two basic forms of AD. The common (>95%) form is sporadic, and is caused by the failure to clear Aβ (mean age at onset 80 years). The rare (< 5%) autosomal dominant familial form is caused by the over-production of Aβ42, also on a background of failure to clear (mean age at onset 45 years). In both forms, the kinetics of Aβ accumulation are similar, taking about 30 years to accumulate a total of approximately 7mg of Aβ. Thus we estimate that sporadic AD starts about the age of 50 years and the autosomal dominant form starts about 15 years of age. The first changes are seen in the Default Mode Network, a brain system that is used for high level coordination of the encoding of memories (the engram), which is the essential first step in learning. We now know that deficits of learning are more severe than memory in the early phases of AD. This may be related to the normal function of the APP molecule that gives rise to Aβ.
The advent of validated biomarkers (PET and biofluids Aβ and tau) now provides us with unprecedented opportunities for preclinical diagnosis, enabling the development of primary and secondary prevention strategies. Predictive algorithms utilizing age, biomarkers, polygenic and vascular risk scores are now being developed from longitudinal cohort studies to estimate times of onset and rates of cognitive decline. Applications of biomarker screens (blood, CSF, PET) to subjects who are about to cross the lower cutpoint thresholds will define a population who may be suitable for primary prevention clinical trials.
Therapeutic targeting the Aβ pathway remains the principal strategy for delaying onset of AD. There are many molecular targets in this pathway, and no single one is likely to prove efficacious on its own. Therefore, a combination of strategies needs to be developed and applied. The recent accelerated successes of aducanumab, Lecanemab and Donanemab , which target an epitope of Aβ, has provided a huge impetus for the development of this first-in-class disease-modifying therapy. Primary and secondary prevention trials are now underway.
Qiao-Xin Li1, Colin L Masters1, Steven J Collins1
1The Florey, University of Melbourne
Treatment of Alzheimer’s disease (AD) at an early stage with several monoclonal antibody drugs is approved by the Food and Drug Administration (FDA) and has brought hope for millions of people afflicted by this malady. Measurement with the Elecsys® platform of Aβ42, P-tau181 and T-tau in cerebrospinal fluid (CSF) is approved by FDA to confirm underlying AD neuropathology. This biomarker profile is concordant with amyloid PET imaging, and either can be used to enable access to AD-modifying therapies. We report findings of the National Dementia Diagnostics Laboratory (NDDL) in AD biomarker testing in community settings. We also discuss the utility of AD biomarkers and neurofilament light (NfL) in patients when Creutzfeldt-Jakob disease (CJD) was suspected. Diagnosis of CJD can be challenging due to its non-specific symptoms overlapping with other neurological disorders such as AD. Inclusion of the AD biomarker helps the differential diagnosis of patients presenting with suspected CJD, to improve patient care. We also find elevated concentrations of NfL in CSF from some patients with normal T-tau, indicating that NfL abnormalities undetected by T-tau. Blood biomarkers for AD using automated medical devices are on the path for FDA full approval. NDDL is actively involved in assessing the appropriate use of the blood tests.
1The Florey, University of Melbourne
Treatment of Alzheimer’s disease (AD) at an early stage with several monoclonal antibody drugs is approved by the Food and Drug Administration (FDA) and has brought hope for millions of people afflicted by this malady. Measurement with the Elecsys® platform of Aβ42, P-tau181 and T-tau in cerebrospinal fluid (CSF) is approved by FDA to confirm underlying AD neuropathology. This biomarker profile is concordant with amyloid PET imaging, and either can be used to enable access to AD-modifying therapies. We report findings of the National Dementia Diagnostics Laboratory (NDDL) in AD biomarker testing in community settings. We also discuss the utility of AD biomarkers and neurofilament light (NfL) in patients when Creutzfeldt-Jakob disease (CJD) was suspected. Diagnosis of CJD can be challenging due to its non-specific symptoms overlapping with other neurological disorders such as AD. Inclusion of the AD biomarker helps the differential diagnosis of patients presenting with suspected CJD, to improve patient care. We also find elevated concentrations of NfL in CSF from some patients with normal T-tau, indicating that NfL abnormalities undetected by T-tau. Blood biomarkers for AD using automated medical devices are on the path for FDA full approval. NDDL is actively involved in assessing the appropriate use of the blood tests.
2:30 pm
Dhamidhu Eratne1,2, Cherie Chang2, Kruti Patel3, Jeff Smith3, Qiao-Xin Li4, Colin Masters4, Dennis Velakoulis2
1The University of Melbourne; 2The Royal Melbourne Hospital; 3Walter and Eliza Hall Institute of Medicine; 4The Florey;
Introduction:
1The University of Melbourne; 2The Royal Melbourne Hospital; 3Walter and Eliza Hall Institute of Medicine; 4The Florey;
Introduction:
Dementia is associated with unacceptable rates of misdiagnosis and years of diagnostic delay. Distinguishing neurodegenerative dementia (ND) from primary psychiatric disorders (PPD), given frequent overlapping symptoms, can be challenging. The Markers in Neuropsychiatric Disorders Study (The MiND Study) is investigating the diagnostic and wider utility of blood based biomarkers such as neurofilament light chain (NfL), glial fibrillary acidic protein (GFAP), phosphorylated tau (p-tau), as well as other markers, to improve timely and accurate diagnosis of neurodegenerative dementia (ND) and distinction from primary psychiatric disorders (PPD). This in-progress study has expanded significantly, becoming a robust platform for Australian and international collaborations.
Methods:
Participants have been recruited and blood samples collected across Australia. Longitudinal clinical/diagnostic, questionnaire, cognitive, and health utilisation data is collected. Second timepoint bloods (24 months) are now underway. Samples have been analysed for NfL, GFAP, p-tau217. Ongoing studies are underway investigating genomics, neuroimaging correlates, and qualitative studies.
Results:
Findings from this ongoing study will be presented. Over 1000 participants have been recruited from diverse specialist and community settings. Partnering with public and private pathology services, blood sample collection and storage processes have been developed across most of Australia. Findings thus far include CSF and plasma NfL reference ranges, strong diagnostic utility of blood and CSF NfL to distinguish dementia from PPD, ptau217 to distinguish Alzheimer from non-Alzheimer disease with very high accuracy, and high value placed on NfL testing by participants. Numerous collaborations and sub-studies have developed, investigating cognitive, neuroimaging, genomic markers. Latest findings on performance of NfL in acute psychiatric presentations and the feasibility and performance of routine pathology platforms and analysis technologies, will be presented.
Conclusions:
The MiND Study is large biobank and platform supporting national and international collaborations, pioneering research to lead to clinical translation, with particular focus on clinical translation in to broad clinical settings, younger onset dementia, primary care settings, and non-AD and neurodegenerative mimics such as primary psychiatric disorders. This research establishes the diagnostic utility of NfL and other biomarkers in differentiating ND from PPD. The integration of routine pathology platforms underscores the feasibility of implementing these findings in real-world clinical settings, supporting broader clinical translation. Findings so far are establishing the role, especially in younger people, for a simple blood test and precision diagnostic algorithms to improve diagnosis and care, setting the stage for future clinical translation and improved outcomes for patients, their families, clinical trials, and healthcare systems.