Anti-amyloid Immunotherapy Research Articles

Tau, synapse loss and gliosis progress in an Alzheimer's mouse model after amyloid-β immunotherapy.

While preclinical studies assessing drugs for Alzheimer's disease (AD) are conducted in animal models that usually display only one neuropathological feature of AD, patients present with a complex combination of comorbidities and neuropathologies. Importantly, it is well-established that amyloid (Aβ) plaque and tau tangle accumulation interact in a phase-dependent manner, making it difficult to predict how targeting one might influence the other, as well as downstream degeneration. We developed a transgenic mouse model, APP/PS1xTau22, with progressive cortical Aβ deposition and hippocampal tau neurofibrillary inclusions to investigate how both neuropathologies act jointly to bring about neural degeneration, synapse loss, and glial phenotypes. We then assessed whether applying murine chimeric Aducanumab, an anti-amyloid immunotherapy, could impact the synergistic relationship between amyloid and tau. Drug treatment resulted in a ∼70% reduction in Aβ deposition in hippocampal and cortical areas and produced a robust peri-plaque microglial and astrocytic response. Removing amyloid from the brain did not reverse or slow tau pathology or alter synapse loss. Our findings suggest that, once the interaction between amyloid and tau is set in motion, reducing plaque burden by Aβ immunotherapy may stimulate glial responses, but is insufficient to curb degenerative phenotypes in this model.

Role of Apolipoprotein E in Alzheimer's Disease Pathogenesis, Prognosis and Treatment.

Alzheimer's disease (AD) is an incurable and progressive neurodegenerative disease with increasing prevalence worldwide. Previous trials of anti-amyloid and anti-tau immunotherapy indicate that additional research needs to be conducted on other mechanisms to find curative or disease-modifying therapy. This review focuses on apolipoprotein E (ApoE), a critical protein in brain lipid metabolism that acts specifically in the clearance and transport of lipids and cholesterol. The ApoE4 allele confers substantial gene dose-dependent risk of developing AD and lowers the age of onset of AD, although the mechanisms of influence remain incompletely understood. The other isoforms bring different levels of AD risk. ApoE2 is protective while ApoE3 is the most common isoform and is considered neutral. An overview is presented of the latest information on the role of ApoE in AD pathogenesis with an emphasis on pathways that are involved in AD development and interactions with crucial processes in different cell types in the brain. Elucidating the key interactions of ApoE with multiple aspects of brain function can be useful for designing novel ApoE-targeted therapeutic approaches.

Alzheimer's Disease Anti-Amyloid Immunotherapies: Imaging Recommendations and Practice Considerations for ARIA Monitoring.

With the full FDA approval and centers for Medicare & Medicaid services (CMS) coverage of lecanemab and donanemab, a growing number of practices are offering anti-amyloid immunotherapy to appropriate patients with cognitive impairment (MCI) or mild dementia due to amyloid-positive Alzheimer's disease (AD). The goal of this paper is to provide updated practical considerations for radiologists, including implementation of MR imaging protocols, workflows and reporting and communication practices relevant to anti-amyloid immunotherapy and monitoring for amyloid-related imaging abnormalities (ARIA). Based on consensus discussion within an expanded ASNR Alzheimer's, ARIA, and Dementia study group, we will: (1) summarize the FDA guidelines for evaluation of radiographic ARIA; (2) review the three key MRI sequences for ARIA monitoring and standardized imaging protocols based on ASNR-industry collaborations; (3) provide imaging recommendations for three key patient scenarios; (4) highlight the role of the radiologist in the care team for this population; (5) discuss implementation of MRI protocols to detect ARIA in diverse practice settings; and (6) present results of the 2023 ASNR international neuroradiologist practice survey on dementia and ARIA imaging.ABBREVIATIONS: AD = Alzheimer's disease; ARIA = amyloid-related imaging abnormalities; APOE = apolipoprotein-E; CMS = centers for Medicare & Medicaid services; MCI = mild cognitive impairment.

Severe cerebral amyloid angiopathy related inflammation (CAA-ri) associated with vaccination: Case report and literature review

Cerebral amyloid angiopathy-related inflammation (CAA-ri) is a rapid but reversible autoimmune encephalopathy where spontaneous autoantibody reaction against amyloid beta deposited in cerebral blood vessels produces characteristic neuroinflammatory changes such as vasogenic edema and microhemorrhages on MRI. The term amyloid-related imaging abnormalities (ARIA) is sometimes used to describe these changes but are more often reserved for similar MRI signal abnormalities seen after administration of anti-amyloid immunotherapy, using treatment exposure as an antecedent. It is unclear if there is any biological basis for this dichotomized distinction. We report a case of severe CAA-ri after exposure to SARS-CoV-2 vaccine and performed a literature review of CAA-ri related to vaccination. CAA-ri precipitated by immunogenic triggers other than anti-amyloid therapy would lend support to the hypothesis that ARIA seen on MRI may represent the same disease underpinned by a shared anti-Aβ autoantibody response irrespective of etiology. A thorough history should be taken before labelling CAA-ri as spontaneous.

Amyloid-β peptide signature associated with cerebral amyloid angiopathy in familial Alzheimer’s disease with APPdup and Down syndrome

Alzheimer’s disease (AD) is characterized by extracellular amyloid plaques containing amyloid-β (Aβ) peptides, intraneuronal neurofibrillary tangles, extracellular neuropil threads, and dystrophic neurites surrounding plaques composed of hyperphosphorylated tau protein (pTau). Aβ can also deposit in blood vessel walls leading to cerebral amyloid angiopathy (CAA). While amyloid plaques in AD brains are constant, CAA varies among cases. The study focuses on differences observed between rare and poorly studied patient groups with APP duplications (APPdup) and Down syndrome (DS) reported to have higher frequencies of elevated CAA levels in comparison to sporadic AD (sAD), most of APP mutations, and controls. We compared Aβ and tau pathologies in postmortem brain tissues across cases and Aβ peptides using mass spectrometry (MS). We further characterized the spatial distribution of Aβ peptides with MS-brain imaging. While intraparenchymal Aβ deposits were numerous in sAD, DS with AD (DS-AD) and AD with APP mutations, these were less abundant in APPdup. On the contrary, Aβ deposits in the blood vessels were abundant in APPdup and DS-AD while only APPdup cases displayed high Aβ deposits in capillaries. Investigation of Aβ peptide profiles showed a specific increase in Aβx-37, Aβx-38 and Aβx-40 but not Aβx-42 in APPdup cases and to a lower extent in DS-AD cases. Interestingly, N-truncated Aβ2-x peptides were particularly increased in APPdup compared to all other groups. This result was confirmed by MS-imaging of leptomeningeal and parenchymal vessels from an APPdup case, suggesting that CAA is associated with accumulation of shorter Aβ peptides truncated both at N- and C-termini in blood vessels. Altogether, this study identified striking differences in the localization and composition of Aβ deposits between AD cases, particularly APPdup and DS-AD, both carrying three genomic copies of the APP gene. Detection of specific Aβ peptides in CSF or plasma of these patients could improve the diagnosis of CAA and their inclusion in anti-amyloid immunotherapy treatments.

Temporal Characterization of the Amyloidogenic APPswe/PS1dE9;hAPOE4 Mouse Model of Alzheimer's Disease.

Alzheimer's disease (AD) is a devastating disorder with a global prevalence estimated at 55 million people. In clinical studies administering certain anti-beta-amyloid (Aβ) antibodies, amyloid-related imaging abnormalities (ARIAs) have emerged as major adverse events. The frequency of these events is higher among apolipoprotein ε4 allele carriers (APOE4) compared to non-carriers. To reflect patients most at risk for vascular complications of anti-Aβ immunotherapy, we selected an APPswe/PS1dE9 transgenic mouse model bearing the human APOE4 gene (APPPS1:E4) and compared it with the same APP/PS1 mouse model bearing the human APOE3 gene (APOE ε3 allele; APPPS1:E3). Using histological and biochemical analyses, we characterized mice at three ages: 8, 12, and 16 months. Female and male mice were assayed for general cerebral fibrillar and pyroglutamate (pGlu-3) Aβ deposition, cerebral amyloid angiopathy (CAA), microhemorrhages, apoE and cholesterol composition, astrocytes, microglia, inflammation, lysosomal dysfunction, and neuritic dystrophy. Amyloidosis, lipid deposition, and astrogliosis increased with age in APPPS1:E4 mice, while inflammation did not reveal significant changes with age. In general, APOE4 carriers showed elevated Aβ, apoE, reactive astrocytes, pro-inflammatory cytokines, microglial response, and neuritic dystrophy compared to APOE3 carriers at different ages. These results highlight the potential of the APPPS1:E4 mouse model as a valuable tool in investigating the vascular side effects associated with anti-amyloid immunotherapy.

Alzheimer's Amyloid Hypothesis and Antibody Therapy: Melting Glaciers?

The amyloid cascade hypothesis for Alzheimer's disease is still alive, although heavily challenged. Effective anti-amyloid immunotherapy would confirm the hypothesis' claim that the protein amyloid-beta is the cause of the disease. Two antibodies, aducanumab and lecanemab, have been approved by the U.S. Food and Drug Administration, while a third, donanemab, is under review. The main argument for the FDA approvals is a presumed therapy-induced removal of cerebral amyloid deposits. Lecanemab and donanemab are also thought to cause some statistical delay in the determination of cognitive decline. However, clinical efficacy that is less than with conventional treatment, selection of amyloid-positive trial patients with non-specific amyloid-PET imaging, and uncertain therapy-induced removal of cerebral amyloids in clinical trials cast doubt on this anti-Alzheimer's antibody therapy and hence on the amyloid hypothesis, calling for a more thorough investigation of the negative impact of this type of therapy on the brain.

Aducanumab anti-amyloid immunotherapy induces sustained microglial and immune alterations.

Aducanumab, an anti-amyloid immunotherapy for Alzheimer's disease, efficiently reduces Aβ, though its plaque clearance mechanisms, long-term effects, and effects of discontinuation are not fully understood. We assessed the effect of aducanumab treatment and withdrawal on Aβ, neuritic dystrophy, astrocytes, and microglia in the APP/PS1 amyloid mouse model. We found that reductions in amyloid and neuritic dystrophy during acute treatment were accompanied by microglial and astrocytic activation, and microglial recruitment to plaques and adoption of an aducanumab-specific pro-phagocytic and pro-degradation transcriptomic signature, indicating a role for microglia in aducanumab-mediated Aβ clearance. Reductions in Aβ and dystrophy were sustained 15 but not 30 wk after discontinuation, and reaccumulation of plaques coincided with loss of the microglial aducanumab signature and failure of microglia to reactivate. This suggests that despite the initial benefit from treatment, microglia are unable to respond later to restrain plaque reaccumulation, making further studies on the effect of amyloid-directed immunotherapy withdrawal crucial for assessing long-term safety and efficacy.

Hyperbaric oxygen therapy—a new hope for Alzheimer’s patients: a case report and literature review

The currently available pharmacological anti-dementia treatments provide only temporary and limited benefits. Not surprisingly, patients and professionals increasingly explore non-pharmacological interventions that may alleviate dementia symptoms. Among these interventions is hyperbaric oxygen therapy (HBOT). A brief review is presented on HBOT use in medicine, with its mode of action in dementia, specifically Alzheimer’s disease, as well as a case report of self-initiated HBOT in a 63-year-old man with a clinical diagnosis of probable Alzheimer’s disease. He had over 400 HBOT sessions [2–3 times weekly, with a duration of 30–50 min, in a multi-place hyperbaric chamber at 2 atmospheres absolute (ATA)] over 7 years and use of donepezil (10 mg daily) for the last 3 years when formally diagnosed by the National Health Service (NHS) Memory Service. The patient’s longitudinal neurocognitive and neuroradiological evidence over 7 years of follow-up remained stable (with no major cognitive decline and no behavioral changes) when compared to his initial presentation when diagnosed by the private health provider. His driving remains unimpaired, and he continues to be independent. This highlights the potential HBOT benefits including those on visuospatial ability and activities of daily living in people with Alzheimer’s disease. This case report argues for more extensive research into the clinical effects of HBOT in Alzheimer’s disease. Discussion of HBOT use is along with the latest advances in anti-amyloid immunotherapy for Alzheimer’s disease, as well as HBOT augmentation of current and novel dementia drug delivery via nanotechnology.

Dementia research in 2023: the year of anti-amyloid immunotherapy

Dementia research in 2023: the year of anti-amyloid immunotherapy

Anti-amyloid Monoclonal Antibodies in Alzheimer’s Disease: A New Hope

Objectives: The current review aimed to collect the updated clinical investigations of monoclonal antibodies (mAbs) in Alzheimer’s disease (AD) patients and assess the feasibility and efficacy of the immunotherapies with mAbs in AD. Design: A narrative review. Participants: People with AD. Outcome measures: The occurrence of AD. Results: The failure of all attempts to cure AD during the previous decades by focusing on the pathogenic factors revealed that the pathophysiology of AD is multifaceted. In recent years, anti-amyloid mAbs that exhibit beneficial effects in AD treatment have been marketed, and different studies have attempted to assess their effects. We investigated the current research to determine the potential benefits and outcomes of clinical trials of mAbs in AD cases in the review. Conclusions: This study concentrated on determining how these drugs affect AD pathology. It offers potential support for using anti-amyloid mAb immunotherapy for AD and evaluates the lessons learned from these clinical studies to conduct further research on the beneficial and harmful impacts of these therapeutic agents.

Immunotherapies in Alzheimer's disease: state of the art and potential use in the elderly

The recent positive results of phaseIII clinical trials evaluating the efficacy of anti-amyloid antibodies in Alzheimer's disease may give hope for an approbation in clinical practice soon. Indeed, lecanemab showed cognitive efficacy but also on functional status, quality of life and caregiver burden in the phaseIII CLARITY study. Aducanumab has already received marketing authorization in the United States in 2021 for the treatment of Alzheimer's disease. However, these clinical trials include mostly young participants without significant comorbidities who are not fully representative of the real elderly population. It is therefore necessary to examine the potential use of these treatments in routine care in the elderly population and to identify potential barriers to their use. The presence of cerebral microbleeds and anticoagulation, two frequent conditions in the elderly, could limit the use of anti-amyloid immunotherapy in the geriatric population. In this population, another limitation would be the unusually long diagnosis delays given that the anti-amyloid therapies target the earliest stages of the disease. However, the results of the phaseIII trials and in particular the subgroup analyses seem indicate a superior cognitive efficacy in elderly subjects, especially those over 75. European recommendations on the future use of these treatments are therefore awaited to clarify this situation, which will probably require a precise analysis of the benefit-risk balance. Age alone cannot be a contraindication to the administration of these treatments.

Detection and treatment of Alzheimer's disease in its preclinical stage.

Longitudinal multimodal biomarker studies reveal that the continuum of Alzheimer's disease (AD) includes a long latent phase, referred to as preclinical AD, which precedes the onset of symptoms by decades. Treatment during the preclinical AD phase offers an optimal opportunity for slowing the progression of disease. However, trial design in this population is complex. In this Review, we discuss the recent advances in accurate plasma measurements, new recruitment approaches, sensitive cognitive instruments and self-reported outcomes that have facilitated the successful launch of multiple phase 3 trials for preclinical AD. The recent success of anti-amyloid immunotherapy trials in symptomatic AD has increased the enthusiasm for testing this strategy at the earliest feasible stage. We provide an outlook for standard screening of amyloid accumulation at the preclinical stage in clinically normal individuals, during which effective therapy to delay or prevent cognitive decline can be initiated.

Inflammatory Cerebral Amyloid Angiopathy: A Broad Clinical Spectrum.

Cerebral amyloid angiopathy (CAA) is a common central nervous system (CNS) vasculopathy, which in some cases is associated with subacute encephalopathy, seizures, headaches, or strokes due to vascular inflammation directed against vascular amyloid accumulation. The pathological subtypes of inflammatory CAA include CAA-related inflammation (CAAri) with mostly perivascular lymphocytic infiltrates, or amyloid-beta (Aβ)-related angiitis (ABRA) with transmural granulomatous inflammation. CAAri and ABRA probably represent part of the spectrum of CNS vasculopathies, intermediate between CAA and primary CNS vasculitis, and they are closely related to Aβ-related imaging abnormalities and other manifestations of an inflammatory response directed against Aβ in the leptomeninges and cerebral parenchyma. As treatment strategies in Alzheimer's disease shift toward potentially effective antiamyloid immunotherapy, the incidence rate of inflammatory CAA (which is probably an underrecognized condition) is likely to increase. Its clinical features are varied and include subacute encephalopathy, behavioral symptoms, headaches, seizures, and focal neurological deficits, which necessitate a high degree of suspicion for this disorder that often responds to treatment. The recent definition of the typical clinical and radiological syndrome has increased its recognition and may eliminate the need for invasive histological sampling in at least some affected patients. Here we review the pathophysiology, clinical spectrum, and approach to diagnosis, and discuss illustrative cases that highlight the wide range of clinical presentations.

Glial cell transcriptome analyses in 3xTg-AD mice: Effects of aging, disease progression, and anti-Aβ immunotherapy.

To investigate how changes in expression of glial genes relate to a progression of Alzheimer's disease (AD) pathology, and how anti-Aβ immunotherapy impact these changes, we conducted a transcriptomic analysis for brains from cohorts of 2-, 10-, and 20month old 3xTg-AD mice, and a cross-sectional study in groups of 20month-old mice treated with active DNA Aβ42 immunization, passive immunotherapy, untreated, and wild-type (wt) controls. Twenty-four Formalin-Fixed Paraffin-Embedded (FFPE) mouse brain sections were used for the gene expression analyses (nanostring). Adjacent sections from these and additional mouse brains were stained for microglia using antibodies detecting IbaI and Gal3. For a semi-quantitative analysis of increased tau and amyloid pathology with aging and disease progression, a comparison of ELISA results from brains of 12 and 20months old 3xTg-AD mice were shown. Based on the different comparisons of transcript numbers found the 3xTg-AD age groups with the senescent 20months old wt control mouse brains, and the 20months old 3xTg-AD mouse brains with the 20months old wt control mouse brains, genes were assigned as upregulated due to aging, or due to disease progression, or due to both. The immunohistochemistry of microglia markers revealed that Gal3 might be an important marker for phagocytosing microglia around amyloid plaques. The comparison of the two anti-Aβ immunotherapy approaches showed a differential downregulation of inflammatory glial genes. These results are relevant for future clinical trials using active anti-amyloid immunotherapy.

Unfairness to Patients With Alzheimer Disease in Medicare’s Coverage of Antiamyloid Immunotherapy

This Viewpoint discusses the US Center for Medicare and Medicaid Services’ decision on aducanumab, a drug that can treat Alzheimer disease.

Differences in the brain transcriptome of glial genes due to aging and active DNA Aβ42 and passive MOAB anti‐Aβ immunotherapy in the 3xTg‐AD mouse strain

Microglia and astrocytes are key players in brain health and disease. Investigating changes in glia gene expression pattern provides further insight into how these cells respond to a progressing AD pathology as well as to changes resulting from removal of pathology components due to anti-Aβ immunotherapy.Mice were immunized with DNA Aβ42 trimer or received passive immunotherapy with the mouse moab 6E10 during the experimental timeline (20 months). Amyloid and tau pathology was evaluated in brains by immunohistochemistry. FFPE sections from the different mouse groups (five groups, n=4/group) were used for transcriptome analyses. Total RNA was isolated from 40 μm FFPE sections and transcript levels for glial genes were determined using the Mouse nCounter Glial Profiling Panel (Nanostring) of 753 genes covering the core pathways, processes, and phenotypic markers of glial cells.We present here a longitudinal analysis for brains from 2, 10, and 20 months old 3xTg-AD mice, and a cross-sectional study for comparison of changes in the brain transcriptome in a group of 20 months old wild-type controls and three groups of 20 months old 3xTg-AD mice which were either treated with active DNA Aβ42 immunization or passive immunotherapy with the anti-Aβ antibody 6E10, or left untreated as controls. In the longitudinal analysis, for 2-, 10-, and 20-months old mice, 13 genes were identified, Tyrobp, Clec7a, Gfap, Gpnmb, Chil1, C1qa, C1qb, C1qc, Cd14, Ctsd, C3, C3ar1, and Trem2, for which high expression could be attributed to AD pathology progression. In a cross-sectional comparison of the two anti-Aβ immunotherapy approaches DNA Aβ42 immunized mice showed more benefits with downregulation of inflammatory glial genes in comparison to mice which had received passive moab immunizations. Transcript of eleven genes, Trem2, Chil1, Gpnmb, Fcrls, Clec7a, C1qa, Tyrobp, Cd68, Apoe, Ctsd, Cst7, were lower in the DNA Aβ42 immunized mice than in the passive moab immunized mice.These data shown here for the first time indicate that active DNA Aβ42 immunotherapy has higher impact on a downregulation of glia activation than passive immunotherapy. Results from this analysis are important for future clinical trials using active anti-amyloid immunotherapy.

Passive antiamyloid immunotherapy for Alzheimer's disease.

Antiamyloid therapy of Alzheimer's disease tackles the overproduction and clearance of the amyloid-beta peptide (Aβ). Immunotherapeutic compounds were tested in large-scale trials. We revisit the recent literature focusing on randomized-controlled trials (RCT) using monoclonal anti-Aβ antibodies. Forty-three articles on anti-Aβ passive immunotherapy for Alzheimer's disease were published between January 2016 and October 2019 regarding 17 RCTs: 13 phase III trials using the monoclonal antibodies bapineuzumab, solanezumab, gantenerumab, crenezumab, and aducanumab; three phase II with crenezumab and aducanumab; and one phase I trial with BAN2401. Studies resulted largely negative considering the effect of the treatment on primary and secondary outcome variables. The incidence of the most important adverse effect, amyloid-related imaging abnormalities (ARIAs) ranged between 0.2 and 22%, in treatment groups. Primary endpoints were not met in eight trials, and five trials were discontinued prior to completion. Passive immunotherapy RCTs failed to show clinically relevant effects in patients with clinically manifest or prodromal dementia. The high incidence of ARIAs indicates that the risk of adverse events may outweigh the benefits of these interventions. Ongoing studies must determine the benefit of such interventions in preclinical Alzheimer's disease, addressing the effect of antiamyloid immunotherapy in samples of asymptomatic carriers of autosomal-dominant mutations related to early-onset Alzheimer's disease.

In Vivo Detection of Amyloid Plaques by Gadolinium-Stained MRI Can Be Used to Demonstrate the Efficacy of an Anti-amyloid Immunotherapy.

Extracellular deposition of β amyloid plaques is an early event associated to Alzheimer’s disease. Here, we have used in vivo gadolinium-stained high resolution (29∗29∗117 μm3) magnetic resonance imaging (MRI) to follow-up in a longitudinal way individual amyloid plaques in APP/PS1 mice and evaluate the efficacy of a new immunotherapy (SAR255952) directed against protofibrillar and fibrillary forms of Aβ. APP/PS1 mice were treated for 5 months between the age of 3.5 and 8.5 months. SAR255952 reduced amyloid load in 8.5-months-old animals, but not in 5.5-months animals compared to mice treated with a control antibody (DM4). Histological evaluation confirmed the reduction of amyloid load and revealed a lower density of amyloid plaques in 8.5-months SAR255952-treated animals. The longitudinal follow-up of individual amyloid plaques by MRI revealed that plaques that were visible at 5.5 months were still visible at 8.5 months in both SAR255952 and DM4-treated mice. This suggests that the amyloid load reduction induced by SAR255952 is related to a slowing down in the formation of new plaques rather than to the clearance of already formed plaques.

Abstract T P221: Anti-amyloid Immunotherapy Results in Exacerbation of Cerebrovascular Disease Through Activation of Matrix Metalloproteinases

Cerebrovascular disease is frequently co-morbid with Alzheimer’s disease (AD) and we hypothesize this co-morbidity could complicate the development of disease-modifying therapies. The amyloid-beta (Aβ) peptide has been the intense focus of therapeutic development for the treatment of AD. One therapeutic approach uses passive immunization against Aβ using anti-Aβ antibodies. We further hypothesize that inflammation mediated activation of MMP9 and MMP2 lead to the exacerbation of cerebrovascular pathologies following immunotherapy. To test our hypothesis we took aged 21 month old APP transgenic mice (PDAPP mice) that have cerebral amyloid angiopathy (CAA) and disruptions of the blood-brain barrier and administered anti-Aβ antibody or control IgG2a for 8 weeks at a dose of 12.5mg/kg. Expression of the MMP2 and MMP9 families were measured by qPCR and Western blot, total Aβ, CAA and albumin for vasogenic edema were measured using immunohistochemistry, and finally, microhemorrhages were assessed with Prussian blue staining. Treatment with the anti-Aβ antibody resulted in significantly decreased Aβ in the frontal cortex and hippocampus. Further, we found increased microhemorrhage associated with increased gene expression of MMP9, MMP2 and MMP14 (the activator of MMP2). Assessment of vasogenic edema, as well as CAA and inflammatory states is currently ongoing. Overall, while anti-Aβ treatment leads to decreased Aβ, cerebrovascular pathologies, most notably microhemorrhages, are increased by immunotherapy. This increased microhemorrhage is associated with increased MMP2 and MMP9 expression. These data suggest that co-morbidity of cerebrovascular pathologies with AD will significantly impair efficacy of therapeutics for AD and could potentially lead to adverse events.