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APOE4 is the strongest genetic risk factor for late-onset Alzheimer’s disease (AD). ApoE4 increases brain amyloid-β (Aβ) pathology relative to other ApoE isoforms1. However, whether APOE independently influences tau pathology, the other major proteinopathy of AD and other tauopathies, or tau-mediated neurodegeneration, is not clear. By generating P301S tau transgenic mice on either a human ApoE knockin (KI) or ApoE knockout (KO) background, we show that P301S/E4 mice have significantly higher tau levels in the brain and a greater extent of somatodendritic tau redistribution by 3 months of age compared to P301S/E2, P301S/E3 and P301S/EKO mice. By 9 months of age, P301S mice with different ApoE genotypes display distinct p-tau staining patterns. P301S/E4 mice develop markedly more brain atrophy and neuroinflammation than P301S/E2 and P301S/E3 mice, whereas P301S/EKO mice are largely protected from these changes. In vitro, E4-expressing microglia exhibit higher innate immune reactivity following LPS treatment. Co-culturing P301S tau-expressing neurons with E4-expressing mixed glia results in a significantly higher level of TNFα secretion and markedly reduced neuronal viability compared to neuron/E2 and neuron/E3 co-cultures. Neurons co-cultured with EKO glia showed the greatest viability with the lowest level of secreted TNFα. Treatment of P301S neurons with recombinant ApoE (E2, E3, E4) also leads to some neuronal damage and death compared to the absence of ApoE, with ApoE4 exacerbating the effect. In individuals with a sporadic primary tauopathy, the presence of an ε4 allele is associated with more severe regional neurodegeneration. In Aβ-pathology positive individuals with symptomatic AD who usually have tau pathology, ε4-carriers demonstrate greater rates of disease progression. Our results demonstrate that ApoE affects tau pathogenesis, neuroinflammation, and tau-mediated neurodegeneration independent of Aβ pathology. ApoE4 exerts a “toxic” gain of function whereas the absence of ApoE is protective.

The National Alzheimer's Coordinating Center (NACC) is responsible for developing and maintaining a database of participant information collected from the 29 Alzheimer's Disease Centers (ADCs) funded by the National Institute on Aging (NIA). The NIA appointed the ADC Clinical Task Force to determine and define an expanded, standardized clinical data set, called the Uniform Data Set (UDS). The goal of the UDS is to provide ADC researchers a standard set of assessment procedures, collected longitudinally, to better characterize ADC participants with mild Alzheimer disease and mild cognitive impairment in comparison with nondemented controls. NACC implemented the UDS (September 2005) by developing data collection forms for initial and follow-up visits based on Clinical Task Force definitions, a relational database, and a data submission system accessible by all ADCs. The NIA requires ADCs to submit UDS data to NACC for all their Clinical Core participants. Thus, the NACC web site (https://www.alz.washington.edu) was enhanced to provide efficient and secure access data submission and retrieval systems.

Purpose Interleukin-15 (IL-15) has significant potential in cancer immunotherapy as an activator of antitumor CD8 T and natural killer (NK) cells. The primary objectives of this trial were to determine safety, adverse event profile, dose-limiting toxicity, and maximum-tolerated dose of recombinant human IL-15 (rhIL-15) administered as a daily intravenous bolus infusion for 12 consecutive days in patients with metastatic malignancy. Patients and Methods We performed a first in-human trial of Escherichia coli–produced rhIL-15. Bolus infusions of 3.0, 1.0, and 0.3 μg/kg per day of IL-15 were administered for 12 consecutive days to patients with metastatic malignant melanoma or metastatic renal cell cancer. Results Flow cytometry of peripheral blood lymphocytes revealed dramatic efflux of NK and memory CD8 T cells from the circulating blood within minutes of IL-15 administration, followed by influx and hyperproliferation yielding 10-fold expansions of NK cells that ultimately returned to baseline. Up to 50-fold increases of serum levels of multiple inflammatory cytokines were observed. Dose-limiting toxicities observed in patients receiving 3.0 and 1.0 μg/kg per day were grade 3 hypotension, thrombocytopenia, and elevations of ALT and AST, resulting in 0.3 μg/kg per day being determined the maximum-tolerated dose. Indications of activity included clearance of lung lesions in two patients. Conclusion IL-15 could be safely administered to patients with metastatic malignancy. IL-15 administration markedly altered homeostasis of lymphocyte subsets in blood, with NK cells and γδ cells most dramatically affected, followed by CD8 memory T cells. To reduce toxicity and increase efficacy, alternative dosing strategies have been initiated, including continuous intravenous infusions and subcutaneous IL-15 administration.

Article abstract-The expression levels of three synaptic proteins (synaptophysin, synaptotagmin,) in AD cases clinically classified by Clinical Dementia Rating (CDR) score were analyzed. Compared with control subjects (CDR ϭ 0), mild (early) AD (CDR ϭ 0.5 to 1) cases had a 25% loss of synaptophysin immunoreactivity. Levels of synaptotagmin and GAP43 were unchanged in mild AD, but cases with CDR of Ͼ1 had a progressive decrement in these synaptic proteins. Thus, synaptic injury in frontal cortex is an early event in AD. The cognitive alterations in patients with AD are closely associated with synaptic loss 1 and neurofibrillary pathology 2 in the limbic system and neocortex. Understanding of the time course of and relationship between neuropathologic and behavioral alteration in AD has been greatly enhanced in recent years by the development of more sensitive neuropsychologic and neuroanatomic tools that can detect subtle cognitive and structural alterations in patients with early AD. Among them, the Clinical Dementia Rating (CDR) scoring system and the Braak staging system 3 have been especially useful. Based on these criteria, some studies have proposed that diffuse amyloid deposits might contribute to neurodegeneration in early stages of the disease, 4 and others have suggested that synaptic and neurofibrillary pathology might be an early/earlier event preceding extracellular amyloid deposition.5 This indicates that alterations in synaptic functioning might occur early in AD and that molecular biomarkers of active synapses, such as synaptotagmin (p65), 6 could be good indicators of early synaptic damage. Synaptotagmin is a 65-kd calcium sensor protein found in the synaptic vesicles that is modulated during synaptic activation. The hypothesis is that changes in synaptotagmin might be the most sensitive indicator of synaptic changes in mild (early) AD. In this context, the main objective of the present study was to analyze expression levels of three synaptic proteins, namely, synaptophysin (general synaptic marker), synaptotagmin (marker of synaptic activity), 7 and growth-associated protein 43 (GAP43; marker of synaptic sprouting) in the brains of patients with mild (early), moderate, and severe AD. Materials and methods.This study was performed with autopsy material from 42 patients (table) studied neurologically and psychometrically during life at the AD Research Center/University of California, San Diego, and at the Washington University School of Medicine, St. Louis, MO. The CDR score was assigned during life following previously published criteria; this scoring has demonstrated interrater reliability.8 Furthermore, to assess the cognitive status just before death, a retrospective CDR score was assigned based on family interviews. Therefore, the CDR score reflects cognitive status right before death. The CDR scale ranged from 0 to 3 (0, 0.5, 1, 2, and 3). Paraffin sections from 4% buffered formalin-fixed neocortical, limbic system, and subcortical material were used for routine neuropathologic examination a...

Cancer immunotherapy is designed to stimulate the immune system to reject and destroy tumors. Recently, interleukin-15 (IL-15), a member of the 4-alpha-helix bundle family of cytokines, has emerged as a candidate immunomodulator for the treatment of cancer. IL-15 acts through its specific receptor, IL-15Rα, which is expressed on antigen-presenting dendritic cells, monocytes and macrophages. IL-15 exhibits broad activity and induces the differentiation and proliferation of T, B and natural killer (NK) cells. It also enhances cytolytic activity of CD8+ T cells and induces long-lasting antigen-experienced CD8+CD44hi memory T cells. IL-15 stimulates differentiation and immunoglobulin synthesis by B cells and induces maturation of dendritic cells. It does not stimulate immunosuppressive T regulatory cells (Tregs). Thus, boosting IL-15 activity could enhance innate and specific immunity and fight tumors. Here we review aspects of IL-15 biology that make it a promising agent for anticancer therapy. We also discuss preclinical models in which IL-15 has demonstrated antitumor activity and highlight ongoing clinical trials of IL-15 in patients with cancer and HIV infection.

Basic research advances in recent years have furthered our understanding of the natural history of Alzheimer’s disease (AD). It is now recognized that pathophysiological changes begin many years prior to clinical manifestations of disease and the spectrum of AD spans from clinically asymptomatic to severely impaired. Defining AD purely by its clinical presentation is thus artificial and efforts have been made to recognize the disease based on both clinical and biomarker findings. Advances with biomarkers have also prompted a shift in how the disease is considered as a clinico-pathophysiological entity, with an increasing appreciation that AD should not only be viewed with discrete and defined clinical stages, but as a multifaceted process moving along a seamless continuum. Acknowledging this concept is critical to understanding the development process for disease-modifying therapies, and for initiating effective diagnostic and disease management options. In this article, we discuss the concept of a disease continuum from pathophysiological, biomarker, and clinical perspectives, and highlight the importance of considering AD as a continuum rather than discrete stages. While the pathophysiology of AD has still not been elucidated completely, there is ample evidence to support researchers and clinicians embracing the view of a disease continuum in their study, diagnosis, and management of the disease.

The global impact of Alzheimer’s disease (AD) continues to increase, and focused efforts are needed to address this immense public health challenge. National leaders have set a goal to prevent or effectively treat AD by 2025. In this paper, we discuss the path to 2025, and what is feasible in this time frame given the realities and challenges of AD drug development, with a focus on disease-modifying therapies (DMTs). Under the current conditions, only drugs currently in late Phase 1 or later will have a chance of being approved by 2025. If pipeline attrition rates remain high, only a few compounds at best will meet this time frame. There is an opportunity to reduce the time and risk of AD drug development through an improvement in trial design; better trial infrastructure; disease registries of well-characterized participant cohorts to help with more rapid enrollment of appropriate study populations; validated biomarkers to better detect disease, determine risk and monitor disease progression as well as predict disease response; more sensitive clinical assessment tools; and faster regulatory review. To implement change requires efforts to build awareness, educate and foster engagement; increase funding for both basic and clinical research; reduce fragmented environments and systems; increase learning from successes and failures; promote data standardization and increase wider data sharing; understand AD at the basic biology level; and rapidly translate new knowledge into clinical development. Improved mechanistic understanding of disease onset and progression is central to more efficient AD drug development and will lead to improved therapeutic approaches and targets. The opportunity for more than a few new therapies by 2025 is small. Accelerating research and clinical development efforts and bringing DMTs to market sooner would have a significant impact on the future societal burden of AD. As these steps are put in place and plans come to fruition, e.g., approval of a DMT, it can be predicted that momentum will build, the process will be self-sustaining, and the path to 2025, and beyond, becomes clearer.