The Use of Episodic Memory Tests for Screening in Clinical Trials for Early Alzheimer's Disease: A Comparison of the Free and Cued Selective Reminding Test (FCSRT) and the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS).

BACKGROUND: Screening procedures for early Alzheimer's disease (AD) trials seek to efficiently identify participants who fulfill clinical and biomarker criteria for AD and enrich for those most likely to experience significant clinical progression during the study. Episodic memory performance is often assessed in screening, but the utility of different memory tests for optimizing screening efficiency and/or rates of clinical progression remains uncertain. OBJECTIVES: Cross-study comparisons of the effects of inclusion criteria based on performance on the Free and Cued Selective Reminding Test (FCSRT) or the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) on screen-failure rates for episodic memory and ß-amyloid (Aß) positivity (by CSF or PET) and on subsequent rates of clinical disease progression in randomized participants across three clinical trials in early (prodromal-to-mild) AD. DESIGN: Secondary analyses of cross-sectional and longitudinal clinical trial data. SETTING: Multi-center international clinical trials. PARTICIPANTS: Individuals with prodromal-to-mild AD screened and/or randomized in clinical trials for crenezumab (CREAD, CREAD2) or semorinemab (Tauriel). Cross-sectional analyses of screening data for episodic memory impairment included participants from CREAD2 (n=2897) and Tauriel (n=887) and for Aß positivity included participants from CREAD (n=1138), CREAD2 (n=1119), and Tauriel (n=483). Longitudinal analyses of rates of clinical progression included participants from CREAD (n=779), CREAD2 (n=773), and Tauriel (n=331). MEASUREMENTS: Cross-sectional analyses examined eligibility rates per cutoffs defined for the FCSRT (CREAD, CREAD2) or RBANS (Tauriel) and per Aß positivity using CSF and/or PET biomarkers. Longitudinal analyses examined rates of clinical progression on the Clinical Dementia Rating-Sum of Boxes (CDR-SB), the 13-item version of the Alzheimer's Disease Assessment Scale-Cognitive Subscale (ADAS-Cog13), and Alzheimer's Disease Cooperative Study-Activities of Daily Living Scale (ADCS-ADL). RESULTS: Lower rates of study eligibility per episodic memory criteria were seen with the FCSRT (CREAD2) relative to the RBANS (Tauriel), but similar rates of eligibility per Aß positivity criteria were seen amongst participants with episodic memory impairment per the cutoffs used on either assessment. Similar rates of clinical decline over 18 months on the CDR-SB, ADAS-Cog13, and ADCS-ADL were observed in study populations enriched using the FCSRT (CREAD, CREAD2) or the RBANS (Tauriel). CONCLUSIONS: Cutoffs for episodic memory impairment on the FCSRT used in the CREAD and CREAD2 studies are more stringent than those on the RBANS used in the Tauriel study, resulting in lower rates of eligibility. However, given that study enrichment with either test yields similar rates of Aß positivity and clinical progression, considerations beyond these factors may drive the decision of which assessment to use for screening in early AD clinical trials.

An essential postsynaptic role for the ubiquitin proteasome system in slow homeostatic synaptic plasticity in cultured hippocampal neurons.

Chronic increases or decreases in neuronal activity initiates compensatory changes in synaptic strength that emerge slowly over a 12-24 h period, but the mechanisms underlying this slow homeostatic response remain poorly understood. Here, we show an essential role for the ubiquitin proteasome system (UPS) in slow homeostatic plasticity induced by chronic changes in network activity. In cultured hippocampal neurons, UPS inhibitors drive a slow increase in miniature excitatory postsynaptic current (mEPSC) amplitude and synaptic AMPA receptor subunit GluA1 and GluA2 expression that both mirrors and occludes the changes produced by chronic suppression of network activity with tetrodotoxin (TTX). These non-additive effects were similarly observed under conditions of chronic hyperactivation of network activity with bicuculline--the increase in mEPSC amplitude and GluA1/2 expression with chronic UPS inhibition persists during network hyperactivation, which scales synaptic strength and AMPA receptor expression in the opposite direction when UPS activity is intact. Finally, cell-autonomous UPS inhibition (via expression of the ubiquitin chain elongation mutant, UbK48R) enhances mEPSC amplitude in a manner that mimics and occludes changes in network activity, demonstrating a postsynaptic role for the UPS in slow homeostatic plasticity. Taken together, our results suggest that the UPS acts as an integration point for translating sustained changes in network activity into appropriate incremental compensatory changes at synapses.

Expression of VLA-2, VLA-3, and alpha(v) integrin receptors in uveal melanoma: association with microvascular architecture of the tumour and prognostic value.

BACKGROUND: The interaction of the integrin receptors with their ligands (collagen, laminin, fibronectin, and others) has a crucial role during the reorganisation of the extracellular matrix and the metastatic process. The presence of particular vascular patterns in uveal melanoma is associated with the development of metastases. There is some evidence that interactions between the tumour cells and the extracellular matrix are responsible for the shape of these patterns. METHODS: The expression of VLA-2, VLA-3, and alpha(v) integrin receptors was examined by immunohistochemistry on paraffin embedded tumour specimens from 92 uveal melanomas (iris melanomas excluded). Possible correlations between these results and the tumour vascular patterns, the histological features of the tumours as well as the clinical outcome of the patients, were investigated. RESULTS: The expression of VLA-2 in tumours was associated with the presence of vascular networks (p = 0.05). Tumours with less than 25% VLA-3 positive cells infiltrated the sclera more frequently than those with more than 25% VLA-3 cell positivity (p = 0.05). Tumours expressing less than 50% alpha(v) positive cells were associated with the mixed or epithelioid cell type (p = 0.05) and, with less statistical precision, with the presence of extraocular growth (p = 0.07). The univariate logistic regression analysis showed that the risk of developing metastases within the first 5 years after diagnosis did not depend on the expression of the integrin receptors investigated. CONCLUSION: The potential biological importance of the associations between integrin expression and the histopathological features of the tumours found in the present study remains to be elucidated in future experiments. The immunohistochemical detection of VLA-2, VLA-3, and alpha(v) integrins had no prognostic value in our preliminary report.

Expression of the cell adhesion molecules ICAM-1, VCAM-1 and NCAM in uveal melanoma: a clinicopathological study.

To investigate the relationship between the expression of the cell adhesion molecules intercellular cell adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1) and neural cell adhesion molecule (NCAM) in uveal melanoma and the metastatic spread in the first 5 years after diagnosis, we performed a hospital-based case-control study with human tissue from 90 patients who underwent enucleation for primary uveal melanoma (iris melanoma excluded). Thirty-five patients developed metastasis within the first 5 years, and 55 patients lived metastasis-free for at least 5 years after enucleation. The paraffin-embedded and formalin-fixed globes were studied by immunohistochemistry with monoclonal antibodies for ICAM-1, VCAM-1 and NCAM. A strong ICAM-1 positivity (more than 75% of the tumor cells stained positive) was detected in 73 tumors (81%). The expression of 75% or less ICAM-1 positive cells in tumors was strongly associated with the development of metastases (odds ratio: 7.5, p = 0.001). Multiple logistic regression models showed that ICAM-1 is an independent risk factor for metastasis even after control for important prognostic markers like extraocular growth, ciliary body involvement, scleral infiltration and cell type. VCAM-1 was expressed in 24 out of 88 tumors (27.3%) and NCAM only in 14 out of 87 tumors (16%). Only spindle cells stained positive with anti-NCAM. NCAM and VCAM-1 expression was not related to metastasis. Our results show that the loss of ICAM-1 expression is associated with an increased risk of metastasis within the first 5 years after diagnosis.