Severe Amyloid Research Articles

Clinical and laboratorial profile of patients with ATTR cardiomyopathy: comparison between wild type and p.Val142Ile forms in the Brazilian population

Abstract Background In Brazil, besides the wild type (wt) form, transthyretin amyloid cardiomyopathy (ATTR-CM) is predominantly caused by hereditary form with Val142Ile mutation. Considering that both forms occur in elderly people, the clinical presentation may be similar. We sought to compare the clinical presentation of patients with wt and Val142Ile mutation in a Brazilian cohort of ATTR-CM patients. Methods Among the 642 patients enrolled in REACT/SP, 283 presented ATTR-CM, being 85 wt and 90 Val142Ile patients. We compared the main clinical characteristics between groups. Results The wt in comparison to Val142Ile patients, respectively, presented: older age (78.4+/-8.5 vs 74.2+/-8.1 y.o., p = 0.0009); similar proportion of males (82% vs 81%, p=0.85); lower proportion of blacks (11% vs 39%, p=0.0001); similar prevalence of heart failure (HF) symptoms (85% vs 79%, p=0.33); higher prevalence of syncope (13% vs 2%, p=0.008) and Pacemakers (PM) implantation (8% vs 1%, p=0.027); similar prevalence of neuropathy manifestations (38% vs 51%, p=0.17); lower creatinine (1.5+/-0.8 vs 2.1+/-2.1 mg/dL, p=0.02) and NT-ProBNP levels (2860.0+/-2843.3 vs. 5488.3+/-5455.6 pg/ml, p=0.0001); reduced interventricular septal thickness (15.6+/-3.3 vs 17.0+/-3.3 mm, p= 0.006), posterior left ventricular (LV) posterior wall thickness (14.2+/-2.4 vs 16.2+/-4.4 mm, p=0.0003), higher LV ejection fraction (52.0+/-10.1 vs 48.2+/-13.6%, p=0.038), higher global LV longitudinal strain (8.6+/-8.7 vs 3.4+/-9.8, p=0.0003), smaller LV diastolic diameter (45.9+/-6.1 vs 43.0+/-7.3 mm, p=0.005) at 2D-Echocardiogram. Conclusions In the Brazilian population wt and Val142Ile patients had similar clinical presentation regarding HF and neuropathy symptoms, but higher prevalence of syncope and PM in wt patients. Conversely, Val142Ile patients presented more severe amyloid cardiac infiltration.

Novel insights into presenilin 1 mutation associated with a distinctive dementia phenotype and cotton wool plaques.

The mutations in the presenilin 1 gene (PSEN1) are the main cause of familial Alzheimer's disease. PSEN1 mutations affect amyloid-beta peptide production, which accumulates in the brain as senile plaque and cotton wool plaques (CWPs) and relates to other neurodegenerative disorders. Here we report the second case of the PSEN1 G266S mutation, which showed distinctive neuropathological features, including abundant CWPs. Lewy body pathology, and altered amyloid-beta production. Using the proband's samples, we performed genetic analysis of the PSEN1, APP, MAPT, and APOE genes, histopathological and immunohistochemical analysis of the brain tissue, and biochemical analysis of Aβ production in COS cells transfected with wild-type or mutant PSEN1. The patient presented with memory loss, abnormal behavior, and visual hallucinations. Brain scans showed reduced blood flow, mild atrophy, and white matter lesions. Genetic analysis revealed a heterozygous mutation at codon 266 (G266S) of PSEN1 and polymorphism of MAPT (Q230R). The brain had many CWPs, severe cerebral amyloid angiopathy (CAA), senile plaque, Lewy bodies, and neurites. Electron microscopy displayed myelinated fiber degeneration, mitochondrial damage, and amyloid fibrils in the white matter. The production level of Aβ42 in PSEN1 G266S-transfected cells significantly increased. Our findings suggest that the PSEN1 G266S mutation may cause a heterogeneous clinical and pathological phenotype, influenced by other genetic or environmental factors.

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.

Deactivation of the Unfolded Protein Response Aggravated Renal AA Amyloidosis in HSF1 Deficiency Mice.

Systemic amyloid A (AA) amyloidosis, which is considered the second most common form of systemic amyloidosis usually takes place several years prior to the occurrence of chronic inflammation, generally involving the kidney. Activated HSF1, which alleviated unfolded protein response (UPR) or enhanced HSR, is the potential therapeutic target of many diseases. However, the effect of HSF1 on AA amyloidosis remains unclear. This study focused on evaluating effect of HSF1 on AA amyloidosis based on HSF1 knockout mice. As a result, aggravated amyloid deposits and renal dysfunction have been found in HSF1 knockout mice. In progressive AA amyloidosis, HSF1 deficiency enhances serum amyloid A production might to lead to severe AA amyloid deposition in mice, which may be related to deactivated unfolded protein response as well as enhanced inflammation. Thus, HSF1 plays a significant role on UPR related pathway impacting AA amyloid deposition, which can mitigate amyloidogenic proteins from aggregation pathologically and is the possible way for intervening with the pathology of systemic amyloid disorder. In conclusion, HSF1 could not only serve as a new target for AA amyloidosis treatment in the future, but HSF1 knockout mice also can be considered as a valuable novel animal model for renal AA amyloidosis.

Screening for Occult Transthyretin Amyloidosis in Patients with Severe Aortic Stenosis and Amyloid Red Flags

Aims: The optimal strategy to identify transthyretin-type cardiac amyloidosis (ATTR-CA) in patients with aortic stenosis (AS) is still unclear. This study aimed to investigate if targeted screening for ATTR-CA in patients with severe AS and amyloid red flags is associated with higher detection rates. Methods: The study prospectively enrolled patients ≥65 years with severe AS. Patients who fulfilled ≥1 major (carpal tunnel syndrome (CTS), ruptured biceps tendon, spinal stenosis, N-terminal pro B-type natriuretic peptide ≥1000 pg/mL, cardiac troponin >99th percentile) or ≥2 minor criteria (diastolic dysfunction ≥2 grade/lateral e’ <10 cm/s, atrial fibrillation, atrioventricular conduction disease/pacemaker) received bone scintigraphy and biochemical analysis for light chain amyloidosis. Hypertensive patients (>140/90 mmHg) and those with interventricular septal thickness (IVSd) ≤13 mm were excluded. Results: Overall, 264 patients were screened, of whom 85 were included in the analysis. Tracer uptake Perugini grade ≥1 was detected in nine patients (11%). An endomyocardial biopsy was additionally performed in four of nine patients, yielding a prevalence of 7% (n = 6). All patients with dual AS-ATTR were male. Syncope was more commonly reported in AS-ATTR patients (50% vs. 6%, p = 0.010), who also tended to have more severe hypertrophy (IVSd of 18 vs. 16 mm, p = 0.075). Pericardial effusion and CTS were more common in patients with dual pathology (67% vs. 8%, p < 0.001, and 83% vs. 24%, p = 0.003, respectively). Conclusion: Targeted screening for ATTR-CA in patients with AS and amyloid red flags does not yield higher detection rates than those reported previously in all comers with AS.

Fatal iatrogenic cerebral β-amyloid-related arteritis in a woman treated with lecanemab for Alzheimer’s disease

We report the case of a 79-year-old woman with Alzheimer’s disease who participated in a Phase III randomized controlled trial called CLARITY-AD testing the experimental drug lecanemab. She was randomized to the placebo group and subsequently enrolled in an open-label extension which guaranteed she received the active drug. After the third biweekly infusion, she suffered a seizure characterized by speech arrest and a generalized convulsion. Magnetic resonance imaging revealed she had multifocal swelling and a marked increase in the number of cerebral microhemorrhages. She was treated with an antiepileptic regimen and high-dose intravenous corticosteroids but continued to worsen and died after 5 days. Post-mortem MRI confirmed extensive microhemorrhages in the temporal, parietal and occipital lobes. The autopsy confirmed the presence of two copies of APOE4, a gene associated with a higher risk of Alzheimer’s disease, and neuropathological features of moderate severity Alzheimer’s disease and severe cerebral amyloid angiopathy with perivascular lymphocytic infiltrates, reactive macrophages and fibrinoid degeneration of vessel walls. There were deposits of β-amyloid in meningeal vessels and penetrating arterioles with numerous microaneurysms. We conclude that the patient likely died as a result of severe cerebral amyloid-related inflammation.

TNFα‐mediated inflammation in mouse models of VCID

AbstractBackgroundTumor necrosis factor alpha (TNFα) is a prominent pleiotropic cytokine with dichotomous effects. Primarily produced in the brain by glial cells, TNFα interacts with two subtypes of TNF receptors (TNFRs) that dictate the cellular response, be that pro‐ or anti‐inflammator. The diverse cellular responses include cell survival, cell death, proliferation, and angiogenesis. Due to the critical role inflammation plays in the pathogenesis of Alzheimer’s disease (AD) and vascular contributions to cognitive impairment and dementia (VCID), understanding the specific roles of pleiotropic cytokines like TNFa in dementia‐causing diseases will provide mechanistic and therapeutic insights. Both inhibition of soluble TNFα (sTNFα) and deletion of pro‐inflammatory TNF receptor 1 (TNFR1) have been shown to decrease severity of amyloid deposition in AD models. However, similar studies have not been conducted regarding VCID outcomes.MethodThis study sought to examine gene and protein expression of TNFα and the two receptors, TNFR1 and TNFR2, within two mouse models of VCID; the hyperhomocysteinemia (HHcy)‐induced VCID co‐morbid with amyloid deposition and aged Tg2576 with severe cerebral amyloid angiopathy (CAA)‐associated VCID. Measures were taken via qPCR for mRNA assessment and Meso Scale Discovery assays (MSD) for protein quantification.ResultIn HHcy‐induced VCID, TNFα mRNA levels were significantly increased regardless of the presence of amyloid deposition. Similarly, protein levels of TNFα trended higher in HHcy groups compared to their controls regardless of amyloid presence. Levels of TNFR1 mRNA trended lower in the HHcy model but was significantly increased in HHcy‐amyloid co‐morbid mice. When investigated in aged Tg2576 mice with CAA, TNFR1 protein expression increased at older timepoints compared to younger, and against wild type controls. Anti‐inflammatory and innate immune‐associated TNFR2 was increased at 20 months in CAA mice when compared to age‐matched controls.ConclusionThese findings display differences in gene and protein expression of TNFa and its receptors in two models of VCID. The unique expression in these models merits further research into the differences in TNF‐mediated inflammation in VCID. Further research is also necessary to determine potential therapeutic advantages of drugs such as TNFα inhibitors in cases of VCID with and without amyloid deposition.

Differential spatial transcriptome profile of the hippocampal formation of protected PSEN1 E280A familial Alzheimer’s disease cases

AbstractBackgroundWe have described two cases with ∼ 30 years of delayed disease onset among carriers of PSEN1 mutation E280A, suffering from familial Alzheimer’s disease (FAD). One case was homozygous for the ApoE Christchurch (hApoEch) mutation. This case showed sparse hyperphosphorylated tau (pTau) pathology in several cortical areas. The second case was heterozygous for the RELN‐COLBOS mutation and was globally affected by severe pTau and amyloid beta pathology, with evidence of localized cellular protection in the entorhinal cortex (EC). Here we used digital spatial profiling (DSP) transcriptomics to characterize the hippocampal formation of FAD protected cases and identify possible molecular mechanisms of protection.MethodsIn depth morphological characterization of the EC together with identification of thirteen different regions of interest (ROIs) were performed in Formalin‐fixed paraffinized 3 mm thick slides taken from the hippocampal formation (Fig. 1A) of the RELN‐COLBOS FAD case, the hApoEch FAD case, three FAD cases, and three sporadic Alzheimer’s cases (SAD). Slides were immunostained for NeuN and GFAP for morphological ROIs identification and processed for localized transcriptome analyses using the GeoMX DSP platform from Nanostring. Obtained data was processed for quality control, dimensionality reduction and differential gene expression (DGE) analyses.ResultsDimensionality reduction of transcriptomic data obtained from all ROIs and studied cases showed a distinctive distribution of ROIs belonging to both protected cases (Fig. 1B). Furthermore, DGE was observed in all sampled ROIs. ROIs such as hippocampal white matter or dentate gyri showed a higher number of differentially expressed genes due to a more homogeneous cellular composition of the ROIs (Fig. 1C). Also, EC and dentate gyrus from FAD protected cases showed distinctive molecular signatures compatible with excitatory neuronal pathways (Fig. 1D). Complementary morphological analyses showed increased neuronal density in the supragranular region of the EC in the RELN‐COLBOS FAD protected case, specifically in neuronal layer II.ConclusionOur results suggest that regardless of the protective gene conferring protection to FAD, the EC is one key protected structure with distinctive regional transcriptomic profiles suggesting the preservation of neuronal function in this region and hinting towards a possible therapeutic target in the protection against Alzheimer’s disease.

Associations of Antemortem Cerebrospinal Fluid Biomarkers with Alzheimer’s Disease Neuropathologic changes at Autopsy

AbstractBackgroundCerebrospinal fluid (CSF) amyloid‐beta 42 (Aβ42) and tau phosphorylated at threonine 181 (p‐tau181) have been widely used as biomarkers for Alzheimer’s disease (AD). AT(N) classification even proposes each substance as a direct biomarker of amyloid (A) and tau (T) pathologies, respectively. However, recent studies suggest that increased CSF p‐tau181 may rather be associated with amyloid pathology. Although neuropathological evaluation at autopsy is the gold standard for assessing these changes, studies evaluating the association between CSF biomarkers and AD neuropathologic changes are limited.MethodWe retrospectively studied patients who underwent antemortem CSF AD biomarker measurement and neuropathological evaluation at autopsy at our institution from 1995 to 2021. CSF biomarkers were measured by ELISA (Fujirebio, Belgium). Neuropathological evaluation of AD was performed routinely regardless of diagnosis and Thal phase, Braak neurofibrillary tangle (NFT) stage, and CERAD score were assessed according to current guidelines.ResultThe mean age of the 119 patients was 76.2 ± 8.9 years; 49 were women. The duration from lumbar puncture to autopsy was median 2 years (0‐13 years). AD pathology was observed in 29 patients (24%). Other common pathologies were Lewy body disease and frontotemporal lobar degeneration. Antemortem CSF Aβ42 and p‐tau181 results were obtained in 119 and 68 patients, respectively. As expected, CSF Aβ42 decreased with increasing Thal phase and CERAD score. CSF p‐tau181 increased with increasing Thal phase, Braak NFT stage, and CERAD score. Even when the analysis was restricted to patients with Braak NFT stage 3 or less (n = 48), CSF p‐tau181 increased mildly with increasing Thal phase and CERAD score. In patients with moderate or severe amyloid pathology by Thal phase or CERAD score (n = 34), CSF p‐tau181 increased more highly at Braak NFT stage 5 or more.ConclusionThe results of this study, which directly compared antemortem CSF biomarkers with AD neuropathologic changes at autopsy, support the current theories that increased CSF p‐tau181 is caused by both amyloid and tau pathology related to AD while decreased CSF Aβ42 is associated with amyloid pathology.

Pathological study on the relationship between nucleic acid oxidative stress and heart failure with preserved ejection fraction in patients aged over 85 years

Objective: To investigate the level of nucleic acid oxidation in myocardial tissue of patients aged over 85 with heart failure with preserved ejection fraction (HFpEF) and the correlation with myocardial amyloid deposition. Methods: This was a retrospective case-control study. Data of patients≥85 years old who underwent systematic pathological autopsy in Beijing Hospital from 2003 to 2017 were retrospectively collected. Twenty-six patients were included in the HFpEF group and 13 age-and sex-matched patients who had not been diagnosed with heart failure and died of non-cardiovascular diseases served as the control group. The left ventricular myocardium slices of both groups were semi-quantitatively analyzed using immunohistochemical staining of 8-oxidized guanine riboside (8-oxo-G) and 8-oxidized guanine deoxyriboside (8-oxo-dG) to evaluate the oxidation of RNA and DNA in cardiomyocytes. Using the median of the mean absorbance value of 8-oxo-G immunohistochemical staining as the cut-off value, patients were divided into high-absorbance group and low-absorbance group. Congo red staining was used to compare myocardial amyloid deposition between the two groups. Results: The mean age of patients in HFpEF group was (91.8±3.7) years, 24 (92.3%) were males. The mean age of patients in control group was (91.7±3.7) years old, 11 (84.6%) were males. The median mean optical absorbance value of 8-oxo-G immunohistochemical staining of myocardium was significantly higher in HFpEF patients than in control group (0.313 8 (0.302 2, 0.340 6) vs. 0.289 2 (0.276 7, 0.299 4), Z=-3.245, P=0.001). The median mean absorbance value of 8-oxo-dG immunohistochemical staining of myocardial tissue was similar between the two groups (0.300 0 (0.290 0, 0.322 5) vs. 0.300 0 (0.290 0, 0.320 0), Z=-0.454, P=0.661). Proportion of patients with moderate and severe cardiac amyloid deposition was significantly higher in the high-absorbance group than in the low-absorbance group ((85.0%, 17/20) vs. (31.6%, 6/19), P=0.001). Conclusion: The RNA oxidation degree of myocardium in HFpEF patients is higher than that in elderly people without heart failure. Degree of myocardial amyloid deposits is higher in patients with high levels of RNA oxidation.

Relationships between Cerebral Vasculopathies and Microinfarcts in a Community-Based Cohort of Older Adults.

Cerebral microinfarcts are associated with cognitive impairment and dementia. Small vessel diseases such as cerebral arteriolosclerosis and cerebral amyloid angiography (CAA) have been found to be associated with microinfarcts. Less is known about the associations of these vasculopathies with the presence, numbers, and location of microinfarcts. These associations were examined in the clinical and autopsy data of 842 participants in the Adult Changes in Thought (ACT) study. Both vasculopathies were categorized by severity (none, mild, moderate, and severe) and region (cortical and subcortical). Odds ratios (OR) and 95% CIs for microinfarcts associated with arteriolosclerosis and CAA adjusted for possible modifying covariates such as age at death, sex, blood pressure, APOE genotype, Braak, and CERAD were estimated. 417 (49.5%) had microinfarcts (cortical, 301; subcortical, 249), 708 (84.1%) had cerebral arteriolosclerosis, 320 (38%) had CAA, and 284 (34%) had both. Ors (95% CI) for any microinfarct were 2.16 (1.46-3.18) and 4.63 (2.90-7.40) for those with moderate (n = 183) and severe (n = 124) arteriolosclerosis, respectively. Respective Ors (95% CI) for the number of microinfarcts were 2.25 (1.54-3.30) and 4.91 (3.18-7.60). Similar associations were observed for cortical and subcortical microinfarcts. Ors (95% Cis) for the number of microinfarcts associated with mild (n = 75), moderate (n = 73), and severe (n = 15) amyloid angiopathy were 0.95 (0.66-1.35), 1.04 (0.71-1.52), and 2.05 (0.94-4.45), respectively. Respective Ors (95% Cis) for cortical microinfarcts were 1.05 (0.71-1.56), 1.50 (0.99-2.27), and 1.69 (0.73-3.91). Respective Ors (95% Cis) for subcortical microinfarcts were 0.84 (0.55-1.28), 0.72 (0.46-1.14), and 0.92 (0.37-2.28). These findings suggest a significant association of cerebral arteriolosclerosis with the presence, number, and location (cortical and subcortical) of microinfarcts, and a weak and non-significant association of CAA with each microinfarct, highlighting the need for future research to better understand the role of small vessel diseases in the pathogenesis of cerebral microinfarcts.

The heterogeneity of asymmetric tau distribution is associated with an early age at onset and poor prognosis in Alzheimer’s disease

AbstractBackgroundThis study aimed to investigate whether an asymmetric tau distribution on PET images could be associated with clinical characteristics and prognosis in prodromal and/or clinical Alzheimer’s disease (AD).MethodThe testing cohort consisted of 60 patients with mild cognitive impairment due to AD and AD dementia from the Alzheimer’s Disease Neuroimaging Initiative – who underwent tau PET imaging with the first‐generation tau tracer [18F]flortaucipir. The validation cohort consisted of an independent sample of 67 patients enrolled from the Shanghai Memory Study who underwent PET tau imaging with the second‐generation tau tracer [18F]APN‐1607. Based on the absolute global tau interhemispheric differences, each cohort was divided into two groups (asymmetric versus symmetric tau distribution). The two groups were cross‐sectionally compared in terms of demographic and cognitive characteristics, as well as pathological burden. The cognitive trajectories of cognitive decline were analyzed longitudinally.ResultFourteen patients (23.3%) in the testing cohort and 26 (38.8%) in the validation cohort showed an asymmetric tau distribution. In both cohorts, cross‐sectional results consistently revealed that an asymmetric tau distribution was associated with an earlier age at disease onset and more severe tau and amyloid burden (Fig 1). In longitudinal analyses, patients with an asymmetric tau distribution were characterized by a steeper cognitive decline (Fig 2).ConclusionAn asymmetric tau distribution on PET images was consistently associated with an earlier age at onset and more severe pathological features of AD in two independent cohorts. Additionally, this imaging biomarker was longitudinally associated with a more rapid trajectory of cognitive decline.

The niacin receptor HCAR2 induces a protective response of microglia to amyloid pathology.

AbstractBackgroundDietary intake of niacin correlates with reduced risk of Alzheimer´s disease (AD). Niacin is a ligand for the niacin receptor HCAR2, which, in the brain, is expressed by microglia. HCAR2 ligands have been shown to modulate microglia functions and exert neuroprotective effects in different models of neuronal injury. Therefore, we hypothesized that HCAR2 modulates a protective microglial phenotype in AD, which can be stimulated by HCAR2 agonists.MethodTo assess the role of HCAR2 in amyloid pathology, the brains of the AD animal model 5xFAD and 5xFAD mice lacking Hcar2 gene (5xFAD‐KO) were subjected to transcriptomic, immunohistochemistry and biochemical analysis. Furthermore, to activate HCAR2, 5 month‐old 5xFAD mice were treated with a FDA‐approved formulation of niacin (Niaspan®) daily, by oral gavage for 30 days with 100 mg niacin/kg. Treated animals were sacrificed and the brains were collected for immunohistochemistry and biochemical analysis. To validate that Niaspan® effects were dependent on HCAR2, we performed the same treatment paradigm and analysis using 5xFAD‐KO mice.ResultOur results indicate that microglia significantly induce HCAR2 expression in the AD brain. Lack of Hcar2 in the 5xFAD mice leads to a deficient response of microglia to amyloid pathology, which is accompanied by an increase in plaque load and exacerbation of the amyloid‐associated neuropathology. Niaspan® treatment increased the response of microglia to amyloid pathology, decreased plaque burden in 5xFAD, and exerted a neuroprotective effect evidenced by reduced neuronal loss in the subiculum, accompanied by a rescue of working memory deficits. Niaspan® did not induce these beneficial effects in 5xFAD‐KO mice.ConclusionThese data suggest that HCAR2 induces a protective microglial phenotype in AD. Furthermore, activation of HCAR2 by Niaspan® treatment has neuroprotective effects in AD, even after the onset of severe amyloid pathology, possibly through the stimulation of a protective microglia response. Niaspan® is a FDA‐approved drug, thus there is a translational potential of this strategy into clinical practice, supporting further study of this therapeutic approach.

Elevated late-life blood pressure may maintain brain oxygenation and slow amyloid-β accumulation at the expense of cerebral vascular damage.

Hypertension in midlife contributes to cognitive decline and is a modifiable risk factor for dementia. The relationship between late-life hypertension and dementia is less clear. We have investigated the relationship of blood pressure and hypertensive status during late life (after 65 years) to post-mortem markers of Alzheimer's disease (amyloid-β and tau loads); arteriolosclerosis and cerebral amyloid angiopathy; and to biochemical measures of ante-mortem cerebral oxygenation (the myelin-associated glycoprotein:proteolipid protein-1 ratio, which is reduced in chronically hypoperfused brain tissue, and the level of vascular endothelial growth factor-A, which is upregulated by tissue hypoxia); blood-brain barrier damage (indicated by an increase in parenchymal fibrinogen); and pericyte content (platelet-derived growth factor receptor β, which declines with pericyte loss), in Alzheimer's disease (n = 75), vascular (n = 20) and mixed dementia (n = 31) cohorts. Systolic and diastolic blood pressure measurements were obtained retrospectively from clinical records. Non-amyloid small vessel disease and cerebral amyloid angiopathy were scored semiquantitatively. Amyloid-β and tau loads were assessed by field fraction measurement in immunolabelled sections of frontal and parietal lobes. Homogenates of frozen tissue from the contralateral frontal and parietal lobes (cortex and white matter) were used to measure markers of vascular function by enzyme-linked immunosorbent assay. Diastolic (but not systolic) blood pressure was associated with the preservation of cerebral oxygenation, correlating positively with the ratio of myelin-associated glycoprotein to proteolipid protein-1 and negatively with vascular endothelial growth factor-A in both the frontal and parietal cortices. Diastolic blood pressure correlated negatively with parenchymal amyloid-β in the parietal cortex. In dementia cases, elevated late-life diastolic blood pressure was associated with more severe arteriolosclerosis and cerebral amyloid angiopathy, and diastolic blood pressure correlated positively with parenchymal fibrinogen, indicating blood-brain barrier breakdown in both regions of the cortex. Systolic blood pressure was related to lower platelet-derived growth factor receptor β in controls in the frontal cortex and in dementia cases in the superficial white matter. We found no association between blood pressure and tau. Our findings demonstrate a complex relationship between late-life blood pressure, disease pathology and vascular function in dementia. We suggest that hypertension helps to reduce cerebral ischaemia (and may slow amyloid-β accumulation) in the face of increasing cerebral vascular resistance, but exacerbates vascular pathology.

Spontaneous intracerebral haemorrhage associated with early-onset cerebral amyloid angiopathy and Alzheimer’s disease neuropathological changes five decades after cadaveric dura mater graft

Cerebral amyloid angiopathy (CAA) is a small vessel disease, causing spontaneous intracerebral hemorrhage (ICH) in the elderly. It is strongly associated with Alzheimer disease (AD), as most CAA patients show deposition of Aβ—i.e. the basic component of parenchymal Alzheimer amyloid deposits—in the cerebral vessels. Iatrogenic early-onset CAA has been recently identified in patients with a history of traumatic brain injury or other cerebral as well as extra-cerebral lesions that led to neurosurgery or other medical procedures as intravascular embolization by cadaveric dura mater extracts many years before the first ICH event. In those patients, a transmission of Aβ seeds from neurosurgical instruments or from cadaveric dura mater exposure was suggested. We report a 51-year-old woman with unremarkable family history who presented abruptly with aphasia and right hemiparesis. A cerebral left lobar haemorrhagic stroke was documented by neuroimaging. Accurate anamnesis revealed a neurosurgical procedure with cadaveric dura mater graft at the age of 2 years for an arachnoid cyst. The neuropathological examination of the cerebral parietal biopsy showed severe amyloid angiopathy in many leptomeningeal and cortical vessels, as well as abundant parenchymal Aβ deposits, neurofibrillary tangles and neuropil threads. The mechanism involved in the human-to-human transmission of the Aβ proteinopathy remains to be clarified. In our patient the cadaver derived dura used for grafting is a very strong candidate as the source of the transmission. A systematic monitoring of individuals who have had neurosurgical procedures in early life, especially those involving cadaveric dural grafts, is required to determine the ratio of those affected by CAA many years later and unaffected. Moreover, our report confirms that in addition to vascular and parenchymal Aβ pathology, neurofibrillary changes indistinguishable from AD may develop in specific conditions with long latency period from the neurosurgical or embolization procedure.

Oligonol ameliorates liver function and brain function in the 5 × FAD mouse model: transcriptional and cellular analysis.

Alzheimer's disease (AD) is a common neurodegenerative disease worldwide and is accompanied by memory deficits, personality changes, anxiety, depression, and social difficulties. For treatment of AD, many researchers have attempted to find medicinal resources with high effectiveness and without side effects. Oligonol is a low molecular weight polypeptide derived from lychee fruit extract. We investigated the effects of oligonol in 5 × FAD transgenic AD mice, which developed severe amyloid pathology, through behavioral tests (Barnes maze, marble burying, and nestle shredding) and molecular experiments. Oligonol treatment attenuated blood glucose levels and increased the antioxidant response in the livers of 5 × FAD mice. Moreover, the behavioral score data showed improvements in anxiety, depressive behavior, and cognitive impairment following a 2-month course of orally administered oligonol. Oligonol treatment not only altered the circulating levels of cytokines and adipokines in 5 × FAD mice, but also significantly enhanced the mRNA and protein levels of antioxidant enzymes and synaptic plasticity in the brain cortex and hippocampus. Therefore, we highlight the therapeutic potential of oligonol to attenuate neuropsychiatric problems and improve memory deficits in the early stage of AD.

Computed tomography pattern of severe cerebral amyloid angiopathy in the acute phase of stroke care: what should we do?

Background: Intracerebral hemorrhage is a complication of thrombolytic therapy in stroke patients. Furthermore, Cerebral Amyloid Angiopathy (CAA), which itself can cause hemorrhage, may be a risk factor for thrombolysis related intracerebral hemorrhage.

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

BackgroundAmyloid-β-related angiitis (ABRA) is a rare complication of cerebral amyloid angiopathy, characterized by amyloid-β 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 presentationA 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.ConclusionsPresentation 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.

Characterizing Amyloid Responsive Microglia in a Cognitively Resilient Patient with Alzheimer’s Disease Neuropathologic Change: A Case Report

AbstractBackgroundCognitive resilience, the discrepancy observed in individuals with high Alzheimer’s disease (AD) neuropathology and near‐normal cognition, is a growing area of study, wherein multiple factors are responsible. Currently, the role of the microglial activation in cognitive resilience is unknown. Herein described is a case report characterizing the amyloid responsive microglia (ARM) in an 88‐year‐old male decedent homozygous for APOE E4, clinically cognitively intact, and found to have AD neuropathologic change (ADNC) upon autopsy.MethodThe participant was enrolled in the Mayo Clinic Study of Aging (MCSA) and continuously followed for 14 years from 73‐ to 87‐years‐old, wherein serial MRI and clinical assessments were obtained. An autopsy was performed upon death, and routine neuropathologic sections were taken. Formalin‐fixed, paraffin‐embedded sections were stained with H&E, and single immunohistochemistry was performed using antibodies against tau (AT8), beta‐amyloid (6F3D), alpha‐synuclein (LB509), TDP‐43 (pS409/410), and CD163 (10D6). Digital image analysis was performed on dorsolateral prefrontal cortex sections scanned at 40x (Leica GT450). ARM (CD163% area) and beta‐amyloid (% area) measurements were obtained using QuPath threshold classifiers. Descriptive statistics were performed (Graphpad).ResultThe decedent was an 88‐year‐old male, homozygous for APOE E4, with a history of three cardiovascular and metabolic conditions, and lifelong smoking. His MMSE (average 28/30) and global cognition (average ‐0.51) were relatively stable (Figure 1), with no clinical concerns for cognitive impairment. Cortical thickness was normal (temporal meta‐ROI>3 mm) on four serial MRIs. The participant reported high cognitive, physical activities, and education‐occupation scores (upper quartile for the 70+ population). Neuropathologic evaluation was notable for severe cerebral amyloid angiopathy, high ADNC (A3B3C3), and remote microinfarcts. CD163‐positive ARM were observed in the neocortices and perivascular spaces, and the ARM:beta‐amyloid ratio was 0.26 (Figure 1). This ARM:beta‐amyloid ratio trended upwards (>90th percentile) compared to APOE E4/E4‐matched‐ and age‐matched controls provided from the University of Pennsylvania.ConclusionThis case report demonstrates a cognitively resilient individual with an elevated ARM:amyloid ratio. Conversely, lower ARM ratios were observed in a cognitively impaired cohort, raising the possibility ARM may associate with cognition. ARM may represent a protective and phagocytic population, and further studies correlating microglia, cognition, and putative mechanism are required.

APOE e4 dependent deficits in brain DHA phospholipids and mfsd2a in Alzheimer’s disease patients with severe cerebral amyloid angiopathy

AbstractBackgroundThe apolipoprotein E e4 allele (APOE4) is a major risk factor, contributing to vascular pathologies in AD which include CAA, BBB dysfunction and reduced cerebral vascular integrity. The diminished capacity of APOE4 to transport docosahexaenoic acid (DHA), an essential fatty acid required for the structural and functional maintenance and vascular integrity of the brain, could also contribute to AD pathogenesis. However, it remains undetermined if changes in the brain DHA content of phospholipids (PL) and DHA transporters exist in relation to APOE4, AD diagnosis and CAA pathology.MethodWe performed liquid chromatography/mass spectrometry‐based PL analysis of the cerebrovascular and parenchymal fractions from autopsied human brain of pathologically confirmed AD cases and controls. We performed an antibody‐based examination of the major facilitator superfamily domain containing 2A (mfsd2a) protein in the cerebrovasculature from these subjects and brain homogenates from transgenic mice with human APOE (APOE‐TR) and APOE‐TR crossed with mice with five AD mutations (EFAD). We performed proteomic analyses of the cerebrovascular and parenchymal fractions of the brains from 50‐week‐old APOE‐TR.ResultIn the cerebrovasculature and parenchyma, DHA containing PL species were lower in ε4 carriers with AD compared to control ε4 carriers. We observed an ε4‐dependent decrease in mfsd2a level in the cerebrovasculature of ε4 carriers compared to non‐carriers. Stratification of DHA containing PL by CAA showed that these PL levels were reduced in ε4 positive AD patients with severe CAA. In addition, brain levels of DHA containing PC species and mfsd2a were lower in APOE4‐TR and E4FAD mice compared to other genotypes in each mouse model. Furthermore, protein levels of glucose transporter 1 (Glut1) and a metabolite transporter, monocarboxylate transporter 1 (MCT1), were lower in the cerebrovasculature of APOE4‐TR relative to APOE3‐TR and APOE2‐TR mice.ConclusionThese findings demonstrate that brain DHA deficiencies in ε4 carriers may be due to reduced mfsd2a expression and partly associated with severe CAA. Thus, targeting this transport mechanism may improve the bioavailability of DHA into the brains of ε4 carriers who are at risk of developing AD.