| 21. |
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| 22. |
- Insel, Philip S., et al.
(författare)
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Accelerating rates of cognitive decline and imaging markers associated with β-amyloid pathology
- 2016
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Ingår i: Neurology. - 0028-3878. ; 86:20, s. 1887-1896
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Tidskriftsartikel (refereegranskat)abstract
- Objective: To estimate points along the spectrum of β-amyloid pathology at which rates of change of several measures of neuronal injury and cognitive decline begin to accelerate. Methods: In 460 patients with mild cognitive impairment (MCI), we estimated the points at which rates of florbetapir PET, fluorodeoxyglucose (FDG) PET, MRI, and cognitive and functional decline begin to accelerate with respect to baseline CSF Aβ 42. Points of initial acceleration in rates of decline were estimated using mixed-effects regression. Results: Rates of neuronal injury and cognitive and even functional decline accelerate substantially before the conventional threshold for amyloid positivity, with rates of florbetapir PET and FDG PET accelerating early. Temporal lobe atrophy rates also accelerate prior to the threshold, but not before the acceleration of cognitive and functional decline. Conclusions: A considerable proportion of patients with MCI would not meet inclusion criteria for a trial using the current threshold for amyloid positivity, even though on average, they are experiencing cognitive/functional decline associated with prethreshold levels of CSF Aβ 42. Future trials in early Alzheimer disease might consider revising the criteria regarding β-amyloid thresholds to include the range of amyloid associated with the first signs of accelerating rates of decline. © 2016 American Academy of Neurology.
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| 23. |
- Insel, Philip S., et al.
(författare)
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Amyloid pathology in the progression to mild cognitive impairment
- 2018
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Ingår i: Neurobiology of Aging. - : Elsevier BV. - 0197-4580. ; 64, s. 76-84
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Tidskriftsartikel (refereegranskat)abstract
- The objective of this study was to determine the cognitive and functional decline and development of brain injury in individuals progressing from preclinical (β-amyloid positive cognitively normal) to prodromal Alzheimer's disease (AD) (β-amyloid positive mild cognitive impairment [MCI]), and compare this with individuals who progress to MCI in the absence of significant amyloid pathology. Seventy-five cognitively healthy participants who progressed to MCI were followed for 4 years on average and up to 10 years. We tested effects of β-amyloid (Aβ) on measures of cognition, functional status, depressive symptoms, and brain structure and metabolism. Preclinical AD subjects showed greater cognitive decline in multiple domains and increased cerebrospinal fluid phosphorylated tau levels at baseline while Aβ-negative progressors showed increased rates of white matter hyperintensity accumulation and had a greater frequency of depressive symptoms at baseline. Aβ status did not influence patterns of brain atrophy, but preclinical AD subjects showed greater decline of brain metabolism than Aβ-negative progressors. Several unique features separate the transition from preclinical to prodromal AD from other causes of cognitive decline. These features may facilitate early diagnosis and treatment of AD, especially in clinical trials aimed at halting the progression from preclinical to prodromal AD.
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| 24. |
- Insel, Philip S., et al.
(författare)
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Assessing risk for preclinical β-amyloid pathology with APOE, cognitive, and demographic information
- 2016
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Ingår i: Alzheimer's and Dementia: Diagnosis, Assessment and Disease Monitoring. - : Wiley. - 2352-8729. ; 4, s. 76-84
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Tidskriftsartikel (refereegranskat)abstract
- Introduction Clinical trials in Alzheimer's disease are aimed at early stages of disease, including preclinical Alzheimer's disease. The high cost and time required to screen large numbers of participants for Aβ pathology impede the development of novel drugs. This study's objective was to evaluate the extent to which inexpensive and easily obtainable information can reduce the number of screen failures by increasing the proportion of Aβ+ participants identified for screening. Methods We used random forest models to evaluate the positive predictive value of demographics, APOE, and longitudinal cognitive rates in the prediction of amyloid pathology, measured by florbetapir PET or cerebrospinal fluid. Results Predicting Aβ positivity with demographic, APOE, and cognitive information yielded a positive predictive value estimate of 0.65 (95% CI, 0.50–0.96), nearly a 60% increase over the reference Aβ+ prevalence in the cohort of 0.41. Conclusions By incorporating this procedure, clinical trial screening costs of 7500 USD per participant may be reduced by nearly 7 million USD total.
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| 25. |
- Insel, Philip S., et al.
(författare)
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Determining clinically meaningful decline in preclinical Alzheimer disease
- 2019
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Ingår i: Neurology. - 1526-632X. ; 93:4, s. 322-333
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: To determine the time required for a preclinical Alzheimer disease population to decline in a meaningful way, use estimates of decline to update previous clinical trial design assumptions, and identify factors that modify β-amyloid (Aβ)-related decline. METHODS: In 1,120 cognitively unimpaired individuals from 3 international cohorts, we estimated the relationship between Aβ status and longitudinal changes across multiple cognitive domains and assessed interactions between Aβ and baseline factors. Power analyses were performed to explore sample size as a function of treatment effect. RESULTS: Cognitively unimpaired Aβ+ participants approach mild cognitive impairment (MCI) levels of performance 6 years after baseline, on average. Achieving 80% power in a simulated 4-year treatment trial, assuming a 25% treatment effect, required 2,000 participants/group. Multiple factors interacted with Aβ to predict cognitive decline; however, these findings were all cohort-specific. Despite design differences across the cohorts, with large sample sizes and sufficient follow-up time, the Aβ+ groups declined consistently on cognitive composite measures. CONCLUSIONS: A preclinical AD population declines to the cognitive performance of an early MCI population in 6 years. Slowing this rate of decline by 40%-50% delays clinically relevant impairment by 3 years-a potentially meaningful treatment effect. However, assuming a 40%-50% drug effect highlights the difficulties in preclinical AD trial design, as a more commonly assumed treatment effect of 25% results in a required sample size of 2,000/group. Designers of preclinical AD treatment trials need to prepare for larger and longer trials than are currently being considered. Interactions with Aβ status were inconsistent and not readily generalizable.
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| 26. |
- Insel, Philip S., et al.
(författare)
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Time to amyloid positivity and preclinical changes in brain metabolism, atrophy, and cognition : Evidence for emerging amyloid pathology in alzheimer's disease
- 2017
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Ingår i: Frontiers in Neuroscience. - : Frontiers Media SA. - 1662-4548 .- 1662-453X. ; 11:MAY
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Tidskriftsartikel (refereegranskat)abstract
- Background: Aβ pathology is associated with longitudinal changes of brain metabolism, atrophy, and cognition, in cognitively healthy elders. However, Aβ information is usually measured cross-sectionally and dichotomized to classify subjects as Aβ-positive or Aβ-negative, making it difficult to evaluate when brain and cognitive changes occur with respect to emerging Aβ pathology. In this study, we use longitudinal Aβ information to combine the level and rate of change of Aβ to estimate the time to Aβ-positivity for each subject and test this temporal proximity to significant Aβ pathology for associations with brain structure, metabolism, and cognition. Methods: In 89 cognitively healthy elders with up to 10 years of follow-up, we estimated the points at which rates of fluorodeoxyglucose (FDG) PET, MRI, and cognitive and functional decline begin to accelerate with respect to the time to Aβ-positivity. Points of initial acceleration in rates of decline were estimated using mixed-effects models with penalized regression splines. Results: Acceleration of rates of FDG PET were observed to occur 20+ years before the conventional threshold for Aβ-positivity. Subtle signs of cognitive dysfunction were observed 10+ years before Aβ-positivity. Conclusions: Aβ may have subtle associations with other hallmarks of Alzheimer's disease before Aβ biomarkers reach conventional thresholds for Aβ-positivity. Therefore, we propose that emerging Aβ pathology occurs many years before cognitively healthy elders reach the current threshold for Aβ positivity (preclinical AD). To allow prevention in the earliest disease stages, AD clinical trials may be designed to also include subjects with Aβ biomarkers in the sub-threshold range.
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| 27. |
- Klebanoff, Mark A., et al.
(författare)
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Antibiotic treatment of bacterial vaginosis to prevent preterm delivery: Systematic review and individual participant data meta-analysis
- 2023
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Ingår i: Paediatric and Perinatal Epidemiology. - : WILEY. - 0269-5022 .- 1365-3016. ; 37:3, s. 239-251
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Forskningsöversikt (refereegranskat)abstract
- BackgroundBacterial vaginosis (BV) increases preterm delivery (PTD) risk, but treatment trials showed mixed results in preventing PTD. ObjectivesDetermine, using individual participant data (IPD), whether BV treatment during pregnancy reduced PTD or prolonged time-to-delivery. Data SourcesCochrane Systematic Review (2013), MEDLINE, EMBASE, journal searches, and searches (January 2013-September 2022) ("bacterial vaginosis AND pregnancy") of (i) ; (ii) Cochrane Central Register of Controlled Trials; (iii) World Health Organization International Clinical Trials Registry Platform Portal; and (iv) Web of Science ("bacterial vaginosis"). Study Selection and Data ExtractionStudies randomising asymptomatic pregnant individuals with BV to antibiotics or control, measuring delivery gestation. Extraction was from original data files. Bias risk was assessed using the Cochrane tool. Analysis used "one-step" logistic and Cox random effect models, adjusting gestation at randomisation and PTD history; heterogeneity by I-2. Subgroup analysis tested interactions with treatment. In sensitivity analyses, studies not providing IPD were incorporated by "multiple random-donor hot-deck" imputation, using IPD studies as donors. ResultsThere were 121 references (96 studies) with 23 eligible trials (11,979 participants); 13 studies (6915 participants) provided IPD; 12 (6115) were incorporated. Results from 9 (4887 participants) not providing IPD were imputed. Odds ratios for PTD for metronidazole and clindamycin versus placebo were 1.00 (95% CI 0.84, 1.17), I-2 = 62%, and 0.59 (95% CI 0.42, 0.82), I-2 = 0 before; and 0.95 (95% CI 0.81, 1.11), I-2 = 59%, and 0.90 (95% CI: 0.72, 1.12), I-2 = 0, after imputation. Time-to-delivery did not differ from null with either treatment. Including imputed IPD, there was no evidence that either drug was more effective when administered earlier, or among those with a PTD history. ConclusionsClindamycin, but not metronidazole, was beneficial in studies providing IPD, but after imputing data from missing IPD studies, treatment of BV during pregnancy did not reduce PTD, nor prolong pregnancy, in any subgroup or when started earlier in gestation.
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| 28. |
- Li, Yan, et al.
(författare)
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Validation of Plasma Amyloid-β 42/40 for Detecting Alzheimer Disease Amyloid Plaques
- 2022
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Ingår i: Neurology. - 0028-3878. ; 98:7, s. 688-699
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Tidskriftsartikel (refereegranskat)abstract
- Background and Objectives To determine the diagnostic accuracy of a plasma Aβ42/Aβ40 assay in classifying amyloid PET status across global research studies using samples collected by multiple centers that utilize different blood collection and processing protocols.MethodsPlasma samples (n = 465) were obtained from 3 large Alzheimer disease (AD) research cohorts in the United States (n = 182), Australia (n = 183), and Sweden (n = 100). Plasma Aβ42/Aβ40 was measured by a high precision immunoprecipitation mass spectrometry (IPMS) assay and compared to the reference standards of amyloid PET and CSF Aβ42/Aβ40.ResultsIn the combined cohort of 465 participants, plasma Aβ42/Aβ40 had good concordance with amyloid PET status (receiver operating characteristic area under the curve [AUC] 0.84, 95% confidence interval [CI] 0.80-0.87); concordance improved with the inclusion of APOE ϵ4 carrier status (AUC 0.88, 95% CI 0.85-0.91). The AUC of plasma Aβ42/Aβ40 with CSF amyloid status was 0.85 (95% CI 0.78-0.91) and improved to 0.93 (95% CI 0.89-0.97) with APOE ϵ4 status. These findings were consistent across the 3 cohorts, despite differences in protocols. The assay performed similarly in both cognitively unimpaired and impaired individuals.DiscussionPlasma Aβ42/Aβ40 is a robust measure for detecting amyloid plaques and can be utilized to aid in the diagnosis of AD, identify those at risk for future dementia due to AD, and improve the diversity of populations enrolled in AD research and clinical trials.Classification of EvidenceThis study provides Class II evidence that plasma Aβ42/Aβ40, as measured by a high precision IPMS assay, accurately diagnoses brain amyloidosis in both cognitively unimpaired and impaired research participants.
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| 29. |
- Mackin, R. Scott, et al.
(författare)
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Late-Life Depression Is Associated With Reduced Cortical Amyloid Burden : Findings From the Alzheimer's Disease Neuroimaging Initiative Depression Project
- 2021
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Ingår i: Biological Psychiatry. - : Elsevier BV. - 0006-3223. ; 89:8, s. 757-765
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Tidskriftsartikel (refereegranskat)abstract
- Background: We evaluated the role of cortical amyloid deposition as a factor contributing to memory dysfunction and increased risk of dementia associated with late-life depression (LLD). Methods: A total of 119 older adult participants with a current diagnosis of major depression (LLD) from the Alzheimer's Disease Neuroimaging Initiative (ADNI) Depression Project study and 119 nondepressed (ND) cognitively unimpaired participants matched on age, sex, and APOE genotype were obtained from the ADNI database. Results: Thirty-three percent of LLD participants met ADNI criteria for mild cognitive impairment. Compared with ND individuals, the LLD group exhibited less global amyloid beta (Aβ) accumulation (p = .05). The proportion of amyloid positivity in the LLD group was 19.3% compared with 31.1% for the ND participants (p = .02). Among LLD participants, global Aβ was not associated with lifetime number of depressive episodes, lifetime length of depression, length of lifetime selective serotonin reuptake inhibitor use, or lifetime length of untreated depression (p >. 21 for all). Global Aβ was associated with worse memory performance (p = .05). Similar results were found in secondary analyses restricting comparisons to the cognitively unimpaired LLD participants as well as when comparing the LLD group with an ND group that included participants with mild cognitive impairment. Conclusions: Contrary to expectation, the LLD group showed less Aβ deposition than the ND group and Aβ deposition was not associated with depression history characteristics. Aβ was associated with memory, but this relationship did not differ between LLD and ND. Our results suggest that memory deficits and accelerated cognitive decline reported in previous studies of LLD are not due to greater cortical Aβ accumulation.
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| 30. |
- Mattsson, Niklas, 1979, et al.
(författare)
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Cerebrospinal fluid tau, neurogranin, and neurofilament light in Alzheimer's disease.
- 2016
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Ingår i: EMBO molecular medicine. - : EMBO. - 1757-4684 .- 1757-4676. ; 8, s. 1184-1196
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Tidskriftsartikel (refereegranskat)abstract
- Cerebrospinal fluid (CSF) tau (total tau, T-tau), neurofilament light (NFL), and neurogranin (Ng) are potential biomarkers for neurodegeneration in Alzheimer's disease (AD). It is unknown whether these biomarkers provide similar or complementary information in AD. We examined 93 patients with AD, 187 patients with mild cognitive impairment, and 109 controls. T-tau, Ng, and NFL were all predictors of AD diagnosis. Combinations improved the diagnostic accuracy (AUC 85.5% for T-tau, Ng, and NFL) compared to individual biomarkers (T-tau 80.8%; Ng 71.4%; NFL 77.7%). T-tau and Ng were highly correlated (ρ=0.79, P<0.001) and strongly associated with β-amyloid (Aβ) pathology, and with longitudinal deterioration in cognition and brain structure, primarily in people with Aβ pathology. NFL on the other hand was not associated with Aβ pathology and was associated with cognitive decline and brain atrophy independent of Aβ. T-tau, Ng, and NFL provide partly independent information about neuronal injury and may be combined to improve the diagnostic accuracy for AD. T-tau and Ng reflect Aβ-dependent neurodegeneration, while NFL reflects neurodegeneration independently of Aβ pathology.
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