Comparison of the clinical impact of 2-[18F]FDG-PET and cerebrospinal fluid biomarkers in patients suspected of Alzheimer's disease

Clinical utility of cerebrospinal fluid Alzheimer's disease biomarkers in the diagnostic workup of complex patients with cognitive impairment

Cerebrospinal fluid (CSF) biomarkers have been widely adopted in Alzheimer's disease (AD) diagnosis. However, no studies focused on the application of CSF biomarkers in the clinical practice of complex and atypical patients with cognitive impairment in China. This study aimed to evaluate the added value of CSF AD biomarkers in cognitively impaired patients with complex conditions in a memory clinical setting. A total of 633 participants were included from the National Center for Neurological Disorders in Shanghai, China. The CSF AD biomarkers were measured with ELISA. Cutoff values were firstly identified using Youden's index. The neurologists proposed etiology diagnosis with a percentage estimate of their confidence and prescribed medication before and after CSF disclosure. Changes in etiological diagnosis, diagnostic confidence, and management plan were compared across the groups. Of the 633 patients (mean [SD] age, 61.1 [11.3] years; 295 males [46.6%]), 372 (58.8%) were diagnosed with dementia, 103 (16.3%) with mild cognitive impairment, and 158 (24.9%) with subjective cognitive decline. Using those pre-defined cutoffs, we categorized patients into 3 groups: Alzheimer's continuum (68.1%), non-AD pathologic change (11.1%), and normal AD biomarkers (20.8%). After CSF disclosure, the proposed etiology changed in 158 (25.0%) participants and the prescribed medication changed in 200 (31.6%) patients. Mean diagnostic confidence increased from 69.5-83.0% (+13.5%; P < 0.001). In conclusion, CSF AD biomarkers significantly impacted the diagnosis, diagnostic confidence, and treatment plans for Chinese patients with complex cognitive impairment. CSF AD biomarkers are a useful tool for clinicians beyond routine clinical assessment.

WIMOAD: Weighted Integration of Multi-Omics data for Alzheimer's Disease (AD) Diagnosis

As the most common subtype of dementia, Alzheimer's disease (AD) is characterized by a progressive decline in cognitive functions, especially in memory, thinking, and reasoning ability. Early diagnosis and interventions enable the implementation of measures to reduce or slow further regression of the disease, preventing individuals from severe brain function decline. The current framework of AD diagnosis depends on A/T/(N) biomarkers detection from cerebrospinal fluid or brain imaging data, which is invasive and expensive during the data acquisition process. Moreover, the pathophysiological changes of AD accumulate in amino acids, metabolism, neuroinflammation, etc., resulting in heterogeneity in newly registered patients. Recently, next generation sequencing (NGS) technologies have found to be a non-invasive, efficient and less-costly alternative on AD screening. However, most of existing studies rely on single omics only. To address these concerns, we introduce WIMOAD, a weighted integration of multi-omics data for AD diagnosis. WIMOAD synergistically leverages specialized classifiers for patients' paired gene expression and methylation data for multi-stage classification. The resulting scores were then stacked with MLP-based meta-models for performance improvement. The prediction results of two distinct meta-models were integrated with optimized weights for the final decision-making of the model, providing higher performance than using single omics only. Remarkably, WIMOAD achieves significantly higher performance than using single omics alone in the classification tasks. The model's overall performance also outperformed most existing approaches, highlighting its ability to effectively discern intricate patterns in multi-omics data and their correlations with clinical diagnosis results. In addition, WIMOAD also stands out as a biologically interpretable model by leveraging the SHapley Additive exPlanations (SHAP) to elucidate the contributions of each gene from each omics to the model output. We believe WIMOAD is a very promising tool for accurate AD diagnosis and effective biomarker discovery across different progression stages, which eventually will have consequential impacts on early treatment intervention and personalized therapy design on AD.

Plasma brain-derived tau is an amyloid-associated neurodegeneration biomarker in Alzheimer's disease

Staging amyloid-beta (Aβ) pathophysiology according to the intensity of neurodegeneration could identify individuals at risk for cognitive decline in Alzheimer's disease (AD). In blood, phosphorylated tau (p-tau) associates with Aβ pathophysiology but an AD-type neurodegeneration biomarker has been lacking. In this multicenter study (n = 1076), we show that brain-derived tau (BD-tau) in blood increases according to concomitant Aβ ("A") and neurodegeneration ("N") abnormalities (determined using cerebrospinal fluid biomarkers); We used blood-based A/N biomarkers to profile the participants in this study; individuals with blood-based p-tau+/BD-tau+ profiles had the fastest cognitive decline and atrophy rates, irrespective of the baseline cognitive status. Furthermore, BD-tau showed no or much weaker correlations with age, renal function, other comorbidities/risk factors and self-identified race/ethnicity, compared with other blood biomarkers. Here we show that blood-based BD-tau is a biomarker for identifying Aβ-positive individuals at risk of short-term cognitive decline and atrophy, with implications for clinical trials and implementation of anti-Aβ therapies.

Translating NIA-AA criteria into usual practice: Report from the ReDeMa Project

INTRODUCTION

Biomarker-informed criteria were proposed for the diagnosis of Alzheimer's disease (AD) by the National Institute on Aging and the Alzheimer's Association (NIA-AA) in 2011; however, the adequacy of this criteria has not been sufficiently evaluated.

METHODS

ReDeMa (Red de Demencias de Madrid) is a regional cohort of patients attending memory and neurology clinics. Core cerebrospinal fluid biomarkers were obtained, NIA-AA diagnostic criteria were considered, and changes in diagnosis and management were evaluated.

RESULTS

A total of 233 patients were analyzed (mean age 70 years, 50% women, 73% AD). The diagnostic language was modified significantly, with a majority assumption of NIA-AA definitions (69%). Confidence in diagnosis increased from 70% to 92% (p < 0.0005) and management was changed in 71% of patient/caregivers. The influence of neurologist's age or expertise on study results was minimal.

DISCUSSION

The NIA-AA criteria are adequate and utile for usual practice in memory and neurology clinics, improving diagnostic confidence and significantly modifying patient management.

HIGHLIGHTS

Alzheimer's disease (AD) cerebrospinal fluid (CSF) biomarkers increase diagnostic certainty regardless of the neurologist.AD CSF biomarkers lead to changes in disease management .Biomarker-enriched, 2011 NIA-AA diagnostic criteria are adequate for usual practice.

Clinical utility of cerebrospinal fluid biomarkers in the evaluation of cognitive impairment: a systematic review and meta-analysis

BACKGROUND

The analytical and clinical validity of cerebrospinal (CSF) biomarkers has been extensively researched in dementia. Further work is needed to assess the ability of these biomarkers to improve diagnosis, management and health outcomes in the clinical setting OBJECTIVES: To assess the added value and clinical utility of CSF biomarkers in the diagnostic assessment of cognitively impaired patients under evaluation for Alzheimer's disease (AD).

METHODS

Systematic literature searches of Medline, EMBASE, PsycINFO and Web of Science research databases were conducted on 17 December 2022. Data from relevant studies were extracted and independently screened for quality using a tool for bias. Clinical utility was measured by clinicians' changes in diagnosis, diagnostic confidence and patient management (when available), after their examination of patients' CSF biomarkers. Cost-effectiveness was assessed by consideration of additional cost per patient and quality-adjusted life years.

RESULTS

Searches identified 17 studies comprising 2090 patient participants and 593 clinicians. The meta-analysis revealed that clinicians' use of CSF biomarkers resulted in a pooled percentage change in diagnosis of 25% (95% CI 14 to 37), an increase in diagnostic confidence of 14% (95% CI 9 to 18) and a pooled proportion of patients whose management changed of 31% (95% CI 12 to 50). CSF biomarkers were deemed cost-effective, particularly in memory services, where pre-test AD prevalence is higher compared with a primary care setting.

CONCLUSIONS

CSF biomarkers can be a helpful additional diagnostic tool for clinicians assessing patients with cognitive impairment. In particular, CSF biomarkers consistently improved clinicians' confidence in diagnosing AD and influenced on diagnostic change and patient management. Further research is needed to study the clinical utility of blood-based biomarkers in the clinical setting.

Biomarkers for the Diagnosis of Alzheimer’s Disease in Clinical Practice: The Role of CSF Biomarkers during the Evolution of Diagnostic Criteria

Alzheimer’s disease (AD) is a progressive condition and the most common cause of dementia worldwide. The neuropathological changes characteristic of the disorder can be successfully detected before the development of full-blown AD. Early diagnosis of the disease constitutes a formidable challenge for clinicians. CSF biomarkers are the in vivo evidence of neuropathological changes developing in the brain of dementia patients. Therefore, measurement of their concentrations allows for improved accuracy of clinical diagnosis. Moreover, AD biomarkers may provide an indication of disease stage. Importantly, the CSF biomarkers of AD play a pivotal role in the new diagnostic criteria for the disease, and in the recent biological definition of AD by the National Institute on Aging, NIH and Alzheimer’s Association. Due to the necessity of collecting CSF by lumbar puncture, the procedure seems to be an important issue not only from a medical, but also a legal, viewpoint. Furthermore, recent technological advances may contribute to the automation of AD biomarkers measurement and may result in the establishment of unified cut-off values and reference limits. Moreover, a group of international experts in the field of AD biomarkers have developed a consensus and guidelines on the interpretation of CSF biomarkers in the context of AD diagnosis. Thus, technological advancement and expert recommendations may contribute to a more widespread use of these diagnostic tests in clinical practice to support a diagnosis of mild cognitive impairment (MCI) or dementia due to AD. This review article presents up-to-date data regarding the usefulness of CSF biomarkers in routine clinical practice and in biomarkers research.

Aβ initiates brain hypometabolism, network dysfunction and behavioral abnormalities via NOX2-induced oxidative stress in mice

A predominant trigger and driver of sporadic Alzheimer’s disease (AD) is the synergy of brain oxidative stress and glucose hypometabolism starting at early preclinical stages. Oxidative stress damages macromolecules, while glucose hypometabolism impairs cellular energy supply and antioxidant defense. However, the exact cause of AD-associated glucose hypometabolism and its network consequences have remained unknown. Here we report NADPH oxidase 2 (NOX2) activation as the main initiating mechanism behind Aβ_1-42-related glucose hypometabolism and network dysfunction. We utilize a combination of electrophysiology with real-time recordings of metabolic transients both ex- and in-vivo to show that Aβ_1-42 induces oxidative stress and acutely reduces cellular glucose consumption followed by long-lasting network hyperactivity and abnormalities in the animal behavioral profile. Critically, all of these pathological changes were prevented by the novel bioavailable NOX2 antagonist GSK2795039. Our data provide direct experimental evidence for causes and consequences of AD-related brain glucose hypometabolism, and suggest that targeting NOX2-mediated oxidative stress is a promising approach to both the prevention and treatment of AD.

Anton Malkov, Irina Popova et al. demonstrate that beta-amyloid application induces oxidative stress and reduces glucose consumption in the mouse brain, leading to network hyperactivity and behavioral changes—pathologies similar to those observed early on in Alzheimer’s disease patients. Inhibition of NADPH oxidase 2 (NOX2) rescued these phenotypes, suggesting that NOX2 may represent an important therapeutic target for Alzheimer’s disease.