Cardiovascular Management in Asymptomatic (Silent) Cerebral Microbleeds and Suspected Cerebral Amyloid Angiopathy.

Cerebral microbleeds (CMBs) detected on blood-sensitive magnetic resonance imaging sequences are usually a sign of an underlying cerebral small vessel disease such as sporadic cerebral amyloid angiopathy or sporadic nonamyloid small vessel pathology (eg, arteriolosclerosis). Much of the enduring interest in CMBs relates to their high prevalence (partly due to the widespread use of magnetic resonance imaging) in the context of stroke, cognitive impairment and in healthy individuals, and the clinical uncertainties created about the safety of antithrombotic medications due to their association with both future hemorrhagic and ischemic stroke. Historically, the research literature overwhelmingly emphasized the future hemorrhagic risk associated with CMBs, potentially leading to unnecessary withholding of treatments proven effective at preventing thrombosis, such as anticoagulants in patients with atrial fibrillation who happened to have some microbleeds. The lack of strong guidelines in this area contributes to wide variation in clinical practice. In this article, we critically review and discuss the implications of silent CMBs and cortical superficial siderosis (ie, without symptomatic intracerebral hemorrhage) in different clinical settings: the general population, patients with ischemic stroke, and the memory clinic. Emerging evidence, albeit not from randomized controlled trials, suggests that in most patients, CMBs alone should not prevent the use of antithrombotics or anticoagulants for stroke prevention, when they are otherwise indicated. Where possible, we provide specific suggestions for clinical care grounded in both the limited available literature and our personal clinical practice.

tPA supplementation preserves neurovascular and cognitive function in Tg2576 mice.

INTRODUCTION: Amyloid beta (Aß) impairs the cerebral blood flow (CBF) increase induced by neural activity (functional hyperemia). Tissue plasminogen activator (tPA) is required for functional hyperemia, and in mouse models of Aß accumulation tPA deficiency contributes to neurovascular and cognitive impairment. However, it remains unknown if tPA supplementation can rescue Aß-induced neurovascular and cognitive dysfunction. METHODS: Tg2576 mice and wild-type littermates received intranasal tPA (0.8 mg/kg/day) or vehicle 5 days a week starting at 11 to 12 months of age and were assessed 3 months later. RESULTS: Treatment of Tg2576 mice with tPA restored resting CBF, prevented the attenuation in functional hyperemia, and improved nesting behavior. These effects were associated with reduced cerebral atrophy and cerebral amyloid angiopathy, but not parenchymal amyloid. DISCUSSION: These findings highlight the key role of tPA deficiency in the neurovascular and cognitive dysfunction associated with amyloid pathology, and suggest potential therapeutic strategies involving tPA reconstitution. HIGHLIGHTS: Amyloid beta (Aß) induces neurovascular dysfunction and impairs the increase of cerebral blood flow induced by neural activity (functional hyperemia). Tissue plasminogen activator (tPA) deficiency contributes to the neurovascular and cognitive dysfunction caused by Aß. In mice with florid amyloid pathology intranasal administration of tPA rescues the neurovascular and cognitive dysfunction and reduces brain atrophy and cerebral amyloid angiopathy. tPA deficiency plays a crucial role in neurovascular and cognitive dysfunction induced by Aß and tPA reconstitution may be of therapeutic value.

Treatment of the CRND8 mouse model for cerebral amyloid angiopathy, exhibited increased levels of neuron specific enolase in brain tissue following long-term treatment with a modified C5a receptor agonist, accompanied by improved cognitive function.

Alzheimer's disease (AD) is an irreversible neurodegenerative disorder characterized by amyloid plaques, neurofibrillary tangles, and cerebral amyloid angiopathy (CAA). CAA is a condition manifesting as amyloid deposits in the cerebral vasculature, eventually leading to microhemorrhage. Here, we have treated the CRND8 mouse model with the C5a agonist (EP67) in order to observe the effects on cerebral amyloidosis, CAA, and hyperphosphorylated tau. EP67 attaches to the C5a receptor on phagocytes and stimulates the engulfment and digestion of fibrillar and prefibrillar amyloid while exhibiting minimal inflammation. Older CRND8 mice and their respective controls were treated with EP67 for a prolonged period of time. Following treatment, the CRND8 mice displayed improved spatial memory, while both amyloid deposition and tau hyperphosphorylation were found to be diminished.

FDA-approved carbonic anhydrase inhibitors reduce amyloid ß pathology and improve cognition, by ameliorating cerebrovascular health and glial fitness.

INTRODUCTION: Cerebrovascular pathology is an early and causal hallmark of Alzheimer's disease (AD), in need of effective therapies. METHODS: Based on the success of our previous in vitro studies, we tested for the first time in a model of AD and cerebral amyloid angiopathy (CAA), the carbonic anhydrase inhibitors (CAIs) methazolamide and acetazolamide, Food and Drug Administration-approved against glaucoma and high-altitude sickness. RESULTS: Both CAIs reduced cerebral, vascular, and glial amyloid beta (Aß) accumulation and caspase activation, diminished gliosis, and ameliorated cognition in TgSwDI mice. The CAIs also improved microvascular fitness and induced protective glial pro-clearance pathways, resulting in the reduction of Aß deposition. Notably, we unveiled that the mitochondrial carbonic anhydrase-VB (CA-VB) is upregulated in TgSwDI brains, CAA and AD+CAA human subjects, and in endothelial cells upon Aß treatment. Strikingly, CA-VB silencing specifically reduces Aß-mediated endothelial apoptosis. DISCUSSION: This work substantiates the potential application of CAIs in clinical trials for AD and CAA.

Brain hemorrhage on 24h-CT and functional outcome in stroke patients with cerebral amyloid angiopathy features on pre-thrombolysis MRI treated with intravenous thrombolysis: A case series.

BACKGROUND AND OBJECTIVES: In stroke patients treated with intravenous thrombolysis (IVT), presence and high number of strictly lobar cerebral microbleeds (compatible with cerebral amyloid angiopathy, CAA) seems to be associated with increased risk of hemorrhagic transformation, symptomatic hemorrhagic transformation, remote hemorrhage, and poor functional outcome. Some of these CAA patients with cerebral microbleeds also have chronic lobar intracerebral hemorrhage. Few data are available on IVT-treated CAA patients showing cortical superficial siderosis. There are no reports studying factors associated with brain hemorrhagic complication or functional outcome in IVT-treated CAA patients. We present a case series study of IVT-treated stroke patients with CAA features on pre-IVT MRI in whom we have evaluated brain hemorrhagic complications on 24 h-CT and functional outcome after IVT. MATERIAL AND METHODS: In our stroke center, IVT decision in patients with CAA MRI features is at the physician's discretion. We retrospectively screened our stroke database between January 2015 and July 2022 for pre-IVT imaging of 959 consecutive IVT-treated stroke patients without ongoing anticoagulation therapy for probable CAA MRI features defined by modified Boston criteria. After exclusion of 119 patients with missing MRI (n = 47), MRI showing motion artefacts (n = 49) or with alternative chronic brain hemorrhage cause on MRI (n = 23), 15 IVT-treated patients with probable CAA on pre-IVT MRI were identified. In these 15 patients, clinical, biological and MRI characteristics were compared between patients with vs. without post-IVT hemorrhage and between patients with poor (MRS 3-6) vs. good (MRS 0-2) functional outcome at discharge. RESULTS: Two patients showed brain hemorrhage on 24 h-CT and both died after 40 and 31 days respectively. The remaining patients had no brain hemorrhage and showed very good outcome except one. Atrial fibrillation (p = 0.029) and Fazekas scale (p = 0.029) were associated with brain hemorrhage whereas atrial fibrillation (p = 0.0022), NIHSS (p = 0.027), blood glucose level (p = 0.024), CRP (p = 0.022) and DWI ASPECT (p = 0.016) were associated with poor outcome. DISCUSSION: Consequences of IVT in CAA patients can be dramatic. Larger studies are needed to compare IVT risks and outcome between CAA and non-CAA patients, also including CAA patients with chronic intracerebral hemorrhage or cortical superficial siderosis. In addition, future studies should try to identify clinical, biological and radiological features at high risk for brain hemorrhage and poor outcome in order to assess the risk-benefit ratio for IVT in CAA. CLINICAL TRIAL REGISTRATION-URL: http://www. CLINICALTRIALS: gov. Unique identifier: NCT05565144.

Impact of previous statin use on first intracerebral hemorrhage in cerebral amyloid angiopathy.

OBJECTIVES: Statins have been associated with an increased risk of spontaneous intracerebral hemorrhage (ICH), but without dedicated study in cerebral amyloid angiopathy (CAA). We aimed to evaluate the association between previous statin treatment and radiological hemorrhagic lesions in a CAA population during a first lobar ICH event. MATERIALS AND METHODS: We retrospectively included all patients meeting the modified Boston criteria for probable CAA and admitted for a first lobar ICH between 2010 and 2021 at Rouen University Hospital. Patients were classified as having previous statin treatment or not. We compared the ICH volume, the number of associated cerebral microbleeds (CMBs), and cortical superficial siderosis (CSS) according to previous statin treatment or not. We also compared functional outcomes and ICH recurrence during the follow-up period between the two groups. RESULTS: We included 99 patients, 27 of whom had statin treatment prior to their ICH. The ICH volume and the number of CMBs did not differ between groups. Disseminated CSS was initially more frequent in the statin group (88% versus 57%; P=0.019), but this was no longer significant after adjustment for antiplatelet treatment (P=0.13). The long-term outcome was similar between the two groups with no increased risk of ICH recurrence in the statin-treated group (29.63% versus 23.61%, P=0.54). CONCLUSIONS: Previous statin treatment was not associated with more severe hemorrhagic lesions in CAA in terms of ICH volume or number of microbleeds, but a trend for increased disseminated CSS was highlighted, which will require further larger studies.

Vessels Sing Their ARIAs: The Role of Vascular Amyloid in the Age of Aducanumab.

We review the implications of the recently approved aducanumab amyloid-ß immunotherapy for treating Alzheimer disease with comorbid cerebral amyloid angiopathy. In clinical trials, amyloid-ß immunotherapy has been associated with a high rate of amyloid-related imaging abnormalities, potentially driven by coexisting cerebral amyloid angiopathy. Therefore, immunotherapy's efficacy in patients may be modified by coexisting cerebrovascular pathology. We discuss the contributions of cerebral amyloid angiopathy on the development of amyloid-related imaging abnormalities and propose strategies to identify cerebral amyloid angiopathy in patients considered for immunotherapy.

Fatal thrombolysis-related intracerebral haemorrhage associated with amyloid-ß-related angiitis in a middle-aged patient - case report and literature review.

BACKGROUND: Amyloid-ß-related angiitis (ABRA) is a rare complication of cerebral amyloid angiopathy, characterized by amyloid-ß deposition in the leptomeningeal and cortical vessels with associated angiodestructive granulomatous inflammation. The clinical presentation is variable, including subacute cognitive decline, behavioural changes, headaches, seizures and focal neurological deficits, which may mimic other conditions. Here, we present a case with fatal thrombolysis-related haemorrhage associated with ABRA in a middle-aged patient. CASE PRESENTATION: A 55-year-old man was admitted to hospital with sudden onset left-sided cheek, arm and hand sensory loss, blurred vision, and worsening headache, with a National Institutes of Health Stroke Scale (NIHSS) score of 3. An acute CT head scan showed no contraindications, and therefore the decision was made to give intravenous thrombolysis. Post-thrombolysis, he showed rapid deterioration with visual disturbances, headache and confusion, and a repeat CT head scan confirmed several areas of intracerebral haemorrhage. No benefit from surgical intervention was expected, and the patient died four days after the first presentation. Neuropathological examination found acute ischemic infarcts of three to five days duration in the basal ganglia, insular cortex and occipital lobe, correlating with the initial clinical symptoms. There were also extensive recent intracerebral haemorrhages most likely secondary to thrombolysis. Furthermore, the histological examination revealed severe cerebral amyloid angiopathy associated with granulomatous inflammatory reaction, consistent with ABRA. CONCLUSIONS: Presentation of ABRA in a middle-aged patient highlighted the difficulties in recognition and management of this rare condition. There is emerging evidence that patients with CAA may have increased risk of fatal intracerebral haemorrhages following thrombolysis. This may be further increased by a coexisting CAA-related inflammatory vasculopathy which is potentially treatable with steroid therapy if early diagnosis is made.

Cerebral amyloid angiopathy-related inflammation with posterior reversible encephalopathy syndrome-like presentation: a case report.

BACKGROUND: Cerebral amyloid angiopathy-related inflammation (CAA-RI), which presents with acute or subacute cognitive or functional decline, focal or multifocal neurologic deficits, new onset of seizures, or a combination of seizures and neurologic deficits, shares clinical and radiologic similarities with posterior reversible encephalopathy syndrome (PRES). Differential diagnosis is critical because the treatment principle for these 2 conditions differs greatly. Here, we present a case of PRES-like CAA-RI and the strategy used to discriminate between the 2 conditions. CASE PRESENTATION: A patient with probable CAA-RI was first thought to suffer from PRES. Initial high-dose methylprednisolone therapy caused rapid improvement of the neurologic symptoms but abrupt discontinuation of corticosteroids resulted in clinical relapse and deterioration. Subsequent reinitiation of high-dose methylprednisolone followed by tapering off of oral prednisone led to clinical and radiologic recovery at the 3-month follow-up. CONCLUSIONS: We suggest that in cases where it is difficult to distinguish between CAA-RI and PRES solely based on magnetic resonance imaging, a good response to corticosteroids and an apolipoprotein E (ApoE) ε4/ε4 genotype are critical for establishing a diagnosis of CAA-RI. If there is clinical deterioration, sudden withdrawal of high-dose corticosteroid during the active phase of CAA-RI should be avoided.

Pleiotropic neuroprotective effects of taxifolin in cerebral amyloid angiopathy.

Cerebral amyloid angiopathy (CAA) results from amyloid-ß deposition in the cerebrovasculature. It is frequently accompanied by Alzheimer's disease and causes dementia. We recently demonstrated that in a mouse model of CAA, taxifolin improved cerebral blood flow, promoted amyloid-ß removal from the brain, and prevented cognitive dysfunction when administered orally. Here we showed that taxifolin inhibited the intracerebral production of amyloid-ß through suppressing the ApoE-ERK1/2-amyloid-ß precursor protein axis, despite the low permeability of the blood-brain barrier to taxifolin. Higher expression levels of triggering receptor expressed on myeloid cell 2 (TREM2) were associated with the exacerbation of inflammation in the brain. Taxifolin suppressed inflammation, alleviating the accumulation of TREM2-expressing cells in the brain. It also mitigated glutamate levels and oxidative tissue damage and reduced brain levels of active caspases, indicative of apoptotic cell death. Thus, the oral administration of taxifolin had intracerebral pleiotropic neuroprotective effects on CAA through suppressing amyloid-ß production and beneficially modulating proinflammatory microglial phenotypes.

[Intracerebral hemorrhage under platelet inhibition and oral anticoagulation in patients with cerebral amyloid angiopathy]. / Intrazerebrale Blutungen unter Plättchenaggregationshemmung und oraler Antikoagulation bei Patienten mit zerebraler Amyloidangiopathie.

Oral anticoagulation in patients with cerebral amyloid angiopathy is a therapeutic challenge. The association of cerebral amyloid angiopathy with intracerebral hemorrhage, a high mortality of intracerebral hemorrhage especially under oral anticoagulation and the high risk of recurrent bleeding require a multidisciplinary approach and a thorough risk-benefit analysis. Vitamin K antagonists increase the risk of intracerebral bleeding and the accompanying mortality by 60% and should be avoided if possible or reserved for special clinical situations (e.g. mechanical aortic valve replacement). Treatment with novel oral anticoagulants and antiplatelet drugs also increases the risk of cerebral bleeding and therefore needs a thorough risk-benefit evaluation. An interventional left atrial appendage closure is a promising therapeutic option especially in patients with an absolute arrythmia with atrial fibrillation. Furthermore, other clinical implications in patients with cerebral amyloid angiopathy are the subject of this review of the literature, such as special characteristics after acute ischemic stroke and the necessary secondary prophylaxis, with previous intracerebral hemorrhage and in patients with cognitive deficits.

Cerebral Amyloid Angiopathy and the Fibrinolytic System: Is Plasmin a Therapeutic Target?

Cerebral amyloid angiopathy is a devastating cause of intracerebral hemorrhage for which there is no specific secondary stroke prevention treatment. Here we review the current literature regarding cerebral amyloid angiopathy pathophysiology and treatment, as well as what is known of the fibrinolytic pathway and its interaction with amyloid. We postulate that tranexamic acid is a potential secondary stroke prevention treatment agent in sporadic cerebral amyloid angiopathy, although further research is required.

Flexible multidentate benzyldiamine derivatives with high affinity for ß-amyloid in cerebral amyloid angiopathy.

Cerebral amyloid angiopathy (CAA) commonly found in the aged is pathologically characterized by ß-amyloid (Aß) deposition in the walls of arteries and capillaries of brain. In this study, four flexible multidentate benzyldiamine derivatives as potential probes for cerebrovascular Aß deposition were designed and synthesized. In in vitro inhibition assays, the ligands 18-21 displayed high affinities for Aß aggregates with Ki values of 1.45 ± 0.53 nM, 1.68 ± 0.35 nM, 1.16 ± 0.23 nM and 1.72 ± 0.19 nM, respectively. A significant improvement in the binding affinity over the monomer, compounds 9-12 or benzyldiamine derivatives, demonstrated the applicability of the multidentate approach. The underlying mechanism of these novel Aß agents was explored by molecular docking technique, which theoretically verified the high affinities of the multidentate benzyldiamine derivatives for Aß aggregates. Moreover, the molecular masses of the ligands 18-21 are more than 700 Dalton, which are believed to be hardly capable of penetrating blood brain barrier. In this regard, these ligands could be used to distinguish CAA from Alzheimer's disease which is another Aß-related disorder disease. To convert these ligands to positron emission tomography imaging agents, we attempted to radiosynthesize [18F]18. Though the radiolabeling was not very successful, the preliminary results suggested that these newly proposed multidentate benzyldiamine derivatives may be used as potential Aß imaging agents in cerebral amyloid angiopathy.

Early Aß reduction prevents progression of cerebral amyloid angiopathy.

OBJECTIVE: Clinical trials targeting ß-amyloid peptides (Aß) for Alzheimer disease (AD) failed for arguable reasons that include selecting the wrong stages of AD pathophysiology or Aß being the wrong target. Targeting Aß to prevent cerebral amyloid angiopathy (CAA) has not been rigorously followed, although the causal role of Aß for CAA and related hemorrhages is undisputed. CAA occurs with normal aging and to various degrees in AD, where its impact and treatment is confounded by the presence of parenchymal Aß deposition. METHODS: APPDutch mice develop CAA in the absence of parenchymal amyloid, mimicking hereditary cerebral hemorrhage with amyloidosis Dutch type (HCHWA-D). Mice were treated with a ß-site amyloid precursor protein cleaving enzyme 1 (BACE1) inhibitor. We used 3-dimensional ultramicroscopy and immunoassays for visualizing CAA and assessing Aß in cerebrospinal fluid (CSF) and brain. RESULTS: CAA onset in mice was at 22 to 24 months, first in frontal leptomeningeal and superficial cortical vessels followed by vessels penetrating the cortical layers. CSF Aß increased with aging followed by a decrease of both Aß40 and Aß42 upon CAA onset, supporting the idea that combined reduction of CSF Aß40 and Aß42 is a specific biomarker for vascular amyloid. BACE1 inhibitor treatment starting at CAA onset and continuing for 4 months revealed a 90% Aß reduction in CSF and largely prevented CAA progression and associated pathologies. INTERPRETATION: This is the first study showing that Aß reduction at early disease time points largely prevents CAA in the absence of parenchymal amyloid. Our observation provides a preclinical basis for Aß-reducing treatments in patients at risk of CAA and in presymptomatic HCHWA-D. ANN NEUROL 2019;86:561-571.

Low-Dose Phosphodiesterase III Inhibitor Reduces the Vascular Amyloid Burden in Amyloid-ß Protein Precursor Transgenic Mice.

A previous study reported that relatively high-dose cilostazol (0.3%) promoted the drainage of cerebrovascular amyloid-ß (Aß) protein in Aß Precursor Protein (APP) transgenic mice overexpressing vasculotropic Aß. We investigated whether lower-dose cilostazol can decrease micro-hemorrhages and Aß deposition in the brain using APP transgenic mice. At baseline, 14-month-old female Tg2576 mice were randomly assigned to a control group (vehicle), aspirin group (0.01% aspirin), or cilostazol group (0.01% cilostazol). The severity of cerebral micro-hemorrhages (i.e., number), area of senile plaque, and severity of vascular amyloid burden (quantified with cerebral amyloid angiopathy (CAA) score (=number of Aß-positive vessels × severity of amyloid burden of Aß-positive vessels) were evaluated in the brain of mice aged 15 and 21-23 months. At 15 months, no differences were shown in each pathological change among the three groups. At 21-23 months, there were no differences in the severity of cerebral micro-hemorrhages or area of senile plaque among the three groups. However, the CAA score was significantly lower in the cilostazol compared to the control group (p = 0.046, Mann-Whitney U test), although no difference was seen between the control and aspirin group. Our study showed that lower-dose cilostazol could reduce the vascular amyloid burden without increasing cerebral micro-hemorrhages in APP transgenic mice.

Potential Therapeutic Approaches for Cerebral Amyloid Angiopathy and Alzheimer's Disease.

Cerebral amyloid angiopathy (CAA) is a cerebrovascular disease directly implicated in Alzheimer's disease (AD) pathogenesis through amyloid-ß (Aß) deposition, which may cause the development and progression of dementia. Despite extensive studies to explore drugs targeting Aß, clinical benefits have not been reported in large clinical trials in AD patients or presymptomatic individuals at a risk for AD. However, recent studies on CAA and AD have provided novel insights regarding CAA- and AD-related pathogenesis. This work has revealed potential therapeutic targets, including Aß drainage pathways, Aß aggregation, oxidative stress, and neuroinflammation. The functional significance and therapeutic potential of bioactive molecules such as cilostazol and taxifolin have also become increasingly evident. Furthermore, recent epidemiological studies have demonstrated that serum levels of a soluble form of triggering receptor expressed on myeloid cells 2 (TREM2) may have clinical significance as a potential novel predictive biomarker for dementia incidence. This review summarizes recent advances in CAA and AD research with a focus on discussing future research directions regarding novel therapeutic approaches and predictive biomarkers for CAA and AD.

Cerebrovascular ß-amyloid deposition and associated microhemorrhages in a Tg2576 Alzheimer mouse model are reduced with a DHA-enriched diet.

Cerebral amyloid angiopathy (CAA) is a major contributor to Alzheimer's disease (AD) pathogenesis. Like AD, CAA is often accompanied by marked inflammation, aggravating associated vasculopathies. No evidence-based prevention or treatment strategies are available. Here, we evaluate the possible beneficial effect of a diet enriched with docosahexaenoic acid (DHA), which is known to attenuate inflammation in CAA. Tg2576 mice, a transgenic model of AD/CAA, were fed a DHA-enriched diet starting at 2 mo of age and ending at 10, 14, or 18 mo of age. ß-Amyloid (Aß)-peptide deposition and bleeding were visualized by immunohistochemistry or histochemistry on coronal sections of the brain. DHA, arachidonic acid, and eicosanoid levels were measured by liquid chromatography/mass spectrometry or GC-MS. DHA-enriched diet throughout aging limits the accumulation of vascular Aß peptide deposits as well as the likelihood of microhemorrhages. There is a strong correlation between systemic 12-hydroxyeicosatetraenoic acid (HETE) levels and the size of the area affected by both vascular amyloid deposits and hemorrhages. The lowest levels of 12-HETE, a lipid-derived proinflammatory product of 12-lipoxygenase (LOX), were found in DHA-fed mice. In vitro experiments performed on amyloid vascular smooth muscle cells showed that a 12-LOX inhibitor almost completely blocked the Aß1-40 peptide-induced apoptosis of these cells. This study yet again highlights the important role of inflammation in CAA pathogenesis and identifies potential new targets for preventive care.-Hur, J., Mateo, V., Amalric, N., Babiak, M., Béréziat, G., Kanony-Truc, C., Clerc, T., Blaise, R., Limon, I. Cerebrovascular ß-amyloid deposition and associated microhemorrhages in a Tg2576 Alzheimer mouse model are reduced with a DHA-enriched diet.

Novel Therapeutic Potentials of Taxifolin for Amyloid-ß-associated Neurodegenerative Diseases and Other Diseases: Recent Advances and Future Perspectives.

Amyloid-ß (Aß) has been closely implicated in the pathogenesis of cerebral amyloid angiopathy (CAA) and Alzheimer's disease (AD), the major causes of dementia. Thus, Aß could be a target for the treatment of these diseases, for which, currently, there are no established effective treatments. Taxifolin is a bioactive catechol-type flavonoid present in various plants, such as herbs, and it exhibits pleiotropic effects including anti-oxidant and anti-glycation activities. Recently, we have demonstrated that taxifolin inhibits Aß fibril formation in vitro and have further shown that it improves cerebral blood flow, facilitating Aß clearance in the brain and suppressing cognitive decline in a mouse model of CAA. These findings suggest the novel therapeutic potentials of taxifolin for CAA. Furthermore, recent extensive studies have reported several novel aspects of taxifolin supporting its potential as a therapeutic drug for AD and metabolic diseases with a high risk for dementia as well as for CAA. In this review, we have summarized the recent advances in taxifolin research based on in vitro, in vivo, and in silico approaches. Furthermore, we have discussed future research directions on the potential of taxifolin for use in novel therapeutic strategies for CAA, AD, and metabolic diseases with an increased risk for dementia.

Norvaline Restores the BBB Integrity in a Mouse Model of Alzheimer's Disease.

Alzheimer's disease (AD) is a chronic neurodegenerative disorder and the leading cause of dementia. The disease progression is associated with the build-up of amyloid plaques and neurofibrillary tangles in the brain. However, besides the well-defined lesions, the AD-related pathology includes neuroinflammation, compromised energy metabolism, and chronic oxidative stress. Likewise, the blood-brain barrier (BBB) dysfunction is suggested to be a cause and AD consequence. Accordingly, therapeutic targeting of the compromised BBB is a promising disease-modifying approach. We utilized a homozygous triple-transgenic mouse model of AD (3×Tg-AD) to assess the effects of L-norvaline on BBB integrity. We scrutinized the perivascular astrocytes and macrophages by measuring the immunopositive profiles in relation to the presence of ß-amyloid and compare the results with those found in wild-type animals. Typically, 3×Tg-AD mice display astroglia cytoskeletal atrophy, associated with the deposition of ß-amyloid in the endothelia, and declining nitric oxide synthase (NOS) levels. L-norvaline escalated NOS levels, then reduced rates of BBB permeability, amyloid angiopathy, microgliosis, and astrodegeneration, which suggests AD treatment agent efficacy. Moreover, results undergird the roles of astrodegeneration and microgliosis in AD-associated BBB dysfunction and progressive cognitive impairment. L-norvaline self-evidently interferes with AD pathogenesis and presents a potent remedy for angiopathies and neurodegenerative disorders intervention.

Innate Immunity Stimulation via Toll-Like Receptor 9 Ameliorates Vascular Amyloid Pathology in Tg-SwDI Mice with Associated Cognitive Benefits.

Alzheimer's disease (AD) is characterized by the presence of parenchymal amyloid-ß (Aß) plaques, cerebral amyloid angiopathy (CAA) and neurofibrillary tangles. Currently there are no effective treatments for AD. Immunotherapeutic approaches under development are hampered by complications related to ineffectual clearance of CAA. Genome-wide association studies have demonstrated the importance of microglia in AD pathogenesis. Microglia are the primary innate immune cells of the brain. Depending on their activation state and environment, microglia can be beneficial or detrimental. In our prior work, we showed that stimulation of innate immunity with Toll-like receptor 9 agonist, class B CpG (cytosine-phosphate-guanine) oligodeoxynucleotides (ODNs), can reduce amyloid and tau pathologies without causing toxicity in Tg2576 and 3xTg-AD mouse models. However, these transgenic mice have relatively little CAA. In the current study, we evaluated the therapeutic profile of CpG ODN in a triple transgenic mouse model, Tg-SwDI, with abundant vascular amyloid, in association with low levels of parenchymal amyloid deposits. Peripheral administration of CpG ODN, both before and after the development of CAA, negated short-term memory deficits, as assessed by object-recognition tests, and was effective at improving spatial and working memory evaluated using a radial arm maze. These findings were associated with significant reductions of CAA pathology lacking adverse effects. Together, our extensive evidence suggests that this innovative immunomodulation may be a safe approach to ameliorate all hallmarks of AD pathology, supporting the potential clinical applicability of CpG ODN. SIGNIFICANCE STATEMENT: Recent genetic studies have underscored the emerging role of microglia in Alzheimer's disease (AD) pathogenesis. Microglia lose their amyloid-ß-clearing capabilities with age and as AD progresses. Therefore, the ability to modulate microglia profiles offers a promising therapeutic avenue for reducing AD pathology. Current immunotherapeutic approaches have been limited by poor clearance of a core AD lesion, cerebral amyloid angiopathy (CAA). The present study used Tg-SwDI mice, which have extensive CAA. We found that stimulation of the innate immune system and microglia/macrophage activation via Toll-like receptor 9 using CpG (cytosine-phosphate-guanine) oligodeoxynucleotides (ODNs) leads to cognitive improvements and CAA reduction, without associated toxicity. Our data indicate that this novel concept of immunomodulation represents a safer method to reduce all aspects of AD pathology and provide essential information for potential clinical use of CpG ODN.