MARCOS VASCONCELOS PAIS
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- Heterogeneity of Cerebrospinal Fluid Biomarkers Profiles in Individuals with Distinct Levels of Cognitive Decline: A Cross-Sectional Study(2021) PAIS, Marcos; LOUREIRO, Julia; VALE, Vagner do; RADANOVIC, Marcia; TALIB, Leda; STELLA, Florindo; FORLENZA, OrestesBackground: Decreased cerebrospinal fluid (CSF) concentrations of the amyloid-beta (A beta), along with increased total (T-tau) and phosphorylated tau protein (P-tau), are widely accepted as core biomarkers of Alzheimer's disease (AD) pathology. Nonetheless, there are a few remaining caveats that still preclude the full incorporation of AD biomarkers into clinical practice. Objective: To determine the frequency of clinical-biological mismatches in a clinical sample of older adults with varying degrees of cognitive impairment. Methods: 204 participants were enrolled for a cross-sectional assessment and allocated into diagnostic groups: probable AD (n = 60, 29.4%); MCI (n = 84, 41.2%); or normal cognition (NC, n = 60, 29.4%). CSF concentrations of A beta(42), T-tau, and (181)Thr-P-tau were determined, and A beta(42)/P-tau ratio below 9.53 was used as a proxy of AD pathology. The AT(N) classification was further used as a framework to ascertain the biological evidence of AD. Results: The majority (73.7%) of patients in the AD group had the A beta(42)/P-tau ratio below the cut-off score for AD, as opposed to a smaller proportion in the MCI (42.9%) and NC (23.3%) groups. In the latter, 21 subjects (35%) were classified as A+, 28 (46.7%) as T+, and 23 (38.3%) as N+. In the AD group, 66.7% of the cases were classified as A+, 78.3% as T+, and 80% as N+. Conclusion: Analysis of CSF biomarkers was able to discriminate between AD, MCI, and NC. However, clinical-biological mismatches were observed in a non-negligible proportion of cases.
- Decision tree-based classification as a support to diagnosis in the Alzheimer's disease continuum using cerebrospinal fluid biomarkers: insights from automated analysis(2022) COSTA, Alana; PAIS, Marcos; LOUREIRO, Julia; STELLA, Florindo; RADANOVIC, Marcia; GATTAZ, Wagner; FORLENZA, Orestes; TALIB, LedaObjective: Cerebrospinal fluid (CSF) biomarkers add accuracy to the diagnostic workup of cognitive impairment by illustrating Alzheimer's disease (AD) pathology. However, there are no universally accepted cutoff values for the interpretation of AD biomarkers. The aim of this study is to determine the viability of a decision-tree method to analyse CSF biomarkers of AD as a support for clinical diagnosis. Methods: A decision-tree method (automated classification analysis) was applied to concentrations of AD biomarkers in CSF as a support for clinical diagnosis in older adults with or without cognitive impairment in a Brazilian cohort. In brief, 272 older adults (68 with AD, 122 with mild cognitive impairment [MCI], and 82 healthy controls) were assessed for CSF concentrations of A beta(1-42), total-tau, and phosphorylated-tau using multiplexed Luminex assays; biomarker values were used to generate decision-tree algorithms (classification and regression tree) in the R statistical software environment. Results: The best decision tree model had an accuracy of 74.65% to differentiate the three groups. Cluster analysis supported the combination of CSF biomarkers to differentiate AD and MCI vs. controls, suggesting the best cutoff values for each clinical condition. Conclusion: Automated analyses of AD biomarkers provide valuable information to support the clinical diagnosis of MCI and AD in research settings.
- Plasma Biomarkers of Alzheimer's Disease: A Review of Available Assays, Recent Developments, and Implications for Clinical Practice(2023) PAIS, Marcos V.; FORLENZA, Orestes V.; DINIZ, Breno S.Recently, low-sensitive plasma assays have been replaced by new ultra-sensitive assays such as single molecule enzyme-linked immunosorbent assay (Simoa), the Mesoscale Discovery (MSD) platform, and immunoprecipitation-mass spectrometry (IP-MS) with higher accuracy in the determination of plasma biomarkers of Alzheimer's disease (AD). Despite the significant variability, many studies have established in-house cut-off values for the most promising available biomarkers. We first reviewed the most used laboratory methods and assays to measure plasma AD biomarkers. Next, we review studies focused on the diagnostic performance of these biomarkers to identify AD cases, predict cognitive decline in pre-clinical AD cases, and differentiate AD cases from other dementia. We summarized data from studies published until January 2023. A combination of plasma A beta(42/40) ratio, age, and APOE status showed the best accuracy in diagnosing brain amyloidosis with a liquid chromatography-mass spectrometry (LC-MS) assay. Plasma p-tau217 has shown the best accuracy in distinguishing A beta-PET+ from A beta-PET- even in cognitively unimpaired individuals. We also summarized the different cut-off values for each biomarker when available. Recently developed assays for plasma biomarkers have undeniable importance in AD research, with improved analytical and diagnostic performance. Some biomarkers have been extensively used in clinical trials and are now clinically available. Nonetheless, several challenges remain to their widespread use in clinical practice.
- Revisiting global cognitive and functional state 13 years after a clinical trial of lithium for mild cognitive impairment(2023) DAMIANO, Rodolfo Furlan; LOUREIRO, Julia Cunha; PAIS, Marcos Vasconcelos; PEREIRA, Rodrigo Furtado; CORRADI, Marina de Menezes; SANTI, Talita Di; BEZERRA, Gustavo Antonio Marcolongo; RADANOVIC, Marcia; TALIB, Leda Leme; FORLENZA, Orestes VicenteObjectives: To re-evaluate a sample of older adults enrolled in a randomized controlled trial of lithium for amnestic mild cognitive impairment (MCI) after 11 to 15 years, re-assessing their current (or last available) global cognitive and functional state.Methods: We recalled all former participants of the Lithium-MCI trial conducted by our group between 2009 and 2012 to perform a single-blinded, cross-sectional evaluation of their global clinical state to compare the long-term outcome of those who received lithium vs. those who received placebo.Results: Of the original sample (n=61), we were able to reach 36 participants (59% of retention), of whom 22 had previously received lithium (61% of the recall sample) and 14 (39%) had received placebo. Since 30.5% of the recalled sample was deceased, psychometric data were collected only for 69.5% of the participants. We found statistically significant differences in current mean Mini Mental State Examination score according to previous treatment group (25.5 [SD, 5.3] vs. 18.3 [SD, 10.9], p = 0.04). The lithium group also had better performance in the phonemic Verbal Fluency Test than the control group (34.4 [SD, 14.4] vs. 11.6 [SD, 10.10], p o 0.001). Differences in these measures also had large effect sizes, as shown by Cohen's d values of 0.92 and 1.78, respectively.Conclusion: This data set suggests that older adults with amnestic MCI who had been treated with lithium during a previous randomized controlled trial had a better long-term global cognitive outcome than those from a matched sample who did not receive the intervention.
- Early diagnosis and treatment of Alzheimer's disease: new definitions and challenges(2020) PAIS, Marcos; MARTINEZ, Luana; RIBEIRO, Octavio; LOUREIRO, Julia; FERNANDEZ, Romel; VALIENGO, Leandro; CANINEU, Paulo; STELLA, Florindo; TALIB, Leda; RADANOVIC, Marcia; FORLENZA, Orestes V.The prevalence of Alzheimer's disease (AD), a progressive neurodegenerative disorder, is expected to more than double by 2050. Studies on the pathophysiology of AD have been changing our understanding of this disorder and setting a new scenario for drug development and other therapies. Concepts like the ""amyloid cascade"" and the ""continuum of AD,"" discussed in this article, are now well established. From updated classifications and recommendations to advances in biomarkers of AD, we aim to critically assess the literature on AD, addressing new definitions and challenges that emerged from recent studies on the subject. Updates on the status of major clinical trials are also given, and future perspectives are discussed.
- Impact of Cognitive Demand on Eye Movement Pattern in Patients with Alzheimer's Disease(2022) CAMARGO, Marina von Zuben de Arruda; PAIS, Marcos Vasconcelos; BELLAN, Ariella Fornachari Ribeiro; TAHIRA, Ana Carolina; SANTOS, Bernardo dos; SANT'ANA, Livea Carla Fidalgo Garcez; RADANOVIC, Marcia; FORLENZA, Orestes VicenteBackground: Eye-movement behavior has been used as a reliable tool to identify cognitive and behavioral patterns in individuals with different neuropsychiatric disorders including Alzheimer's disease (AD). Most studies in the field have been dedicated to evaluating eye-movement behavior during cognitive tasks in different protocols using multiple parameters. Objective: We aimed to evaluate the differences of eye-movement behavior in healthy subjects, subjects with mild cognitive impairment (MCI), and those with AD in a simple color task with and without cognitive demand. Methods: 91 subjects: 18 AD, 47 MCI, and 26 healthy controls had their oculomotor parameters assessed during baseline (no cognitive demand involved) and during a simple computational color memory task using an eye-tracker. Results: Baseline showed statistically different and heterogeneous results between normal cognition and MCI groups. Familiarization phase of the task could not discriminate between groups in any of the analyzed parameters. AD subjects made longer fixations and visits on distractors, and more frequent fixations and visits on the target areas than other groups during the response phase. Conclusion: Eye-tracking time-related parameters differentiate AD subjects from other groups under cognitive demand even in a simple color memory task.