The presence of circulating human apolipoprotein J reduces the occurrence of cerebral microbleeds in a transgenic mouse model with cerebral amyloid angiopathy.

BACKGROUND: Cerebral amyloid angiopathy (CAA) is characterized by amyloid-ß (Aß) deposition in cerebral vessels, leading to lobar cerebral microbleeds (CMB) and intracerebral hemorrhages (ICH). Apolipoprotein J (ApoJ) is a multifunctional chaperone related to Aß aggregation and clearance. Our study investigated the vascular impact of chronic recombinant human Apolipoprotein J (rhApoJ) treatment in a transgenic mouse model of ß-amyloidosis with prominent CAA. METHODS: Twenty-month-old APP23 C57BL/6 mice received 25 doses of rhApoJ (1 mg/kg) (n = 9) or saline (n = 8) intraperitoneally for 13 weeks, while Wild-type (WT) mice received saline (n = 13). Postmortem brains underwent T2*-weighted magnetic resonance imaging (MRI) to detect hemorrhagic lesions. Aß levels and distribution, cerebral fibrinogen leakage, brain smooth muscle actin (sma), and plasma matrix metalloproteinases and inflammatory markers were analyzed after treatments. Additionally, plasma samples from 22 patients with lobar ICH were examined to determine the clinical relevance of the preclinical findings. RESULTS: rhApoJ-treated APP23 presented fewer cortical CMBs (50-300 µm diameter) (p = 0.012) and cortical larger hemorrhages (> 300 µm) (p = 0.002) than saline-treated mice, independently of Aß brain levels. MRI-detected hemorrhagic lesions correlated with fibrinogen cerebral extravasation (p = 0.011). Additionally, rhApoJ-treated mice presented higher number of sma-positive vessels than saline-treated mice (p = 0.038). In rhApoJ-treated mice, human ApoJ was detected in plasma and in occasional leptomeningeal vessels, but not in the parenchyma, suggesting that its mechanism of action operates through the periphery. The administration of rhApoJ induced an increase in plasma Groα (p = 0.035) and MIP-1α (p = 0.035) levels, while lower MMP-12 (p = 0.046) levels, compared to the saline-treated group. In acute lobar ICH patients, MMP-12 plasma levels correlated with larger hemorrhage volume (p = 0.040) and irregular ICH shape (p = 0.036). CONCLUSIONS: Chronic rhApoJ treatment in aged APP23 mice ameliorated CAA-related neurovascular damage by reducing the occurrence of CMB. We propose that rhApoJ may prevent blood-brain barrier (BBB) leakage and CMB appearance partly through circulating MMP-12 modulation.

Apolipoprotein J protects cardiomyocytes from lipid-mediated inflammation and cytotoxicity induced by the epicardial adipose tissue of diabetic patients.

Diabetic patients present increased volume and functional alterations in epicardial adipose tissue (EAT). We aimed to analyze EAT from type 2 diabetic patients and the inflammatory and cytotoxic effects induced on cardiomyocytes. Furthermore, we analyzed the cardioprotective role of apolipoprotein J (apoJ). EAT explants were obtained from nondiabetic patients (ND), diabetic patients without coronary disease (DM), and DM patients with coronary disease (DM-C) after heart surgery. Morphological characteristics and gene expression were evaluated. Explants were cultured for 24 h and the content of nonesterified fatty acids (NEFA) and sphingolipid species in secretomes was evaluated by lipidomic analysis. Afterwards, secretomes were added to AC16 human cardiomyocytes for 24 h in the presence or absence of cardioprotective molecules (apoJ and HDL). Cytokine release and apoptosis/necrosis were assessed by ELISA and flow cytometry. The EAT from the diabetic samples showed altered expression of genes related to lipid accumulation, insulin resistance, and inflammation. The secretomes from the DM samples presented an increased ratio of pro/antiatherogenic ceramide (Cer) species, while those from DM-C contained the highest concentration of saturated NEFA. DM and DM-C secretomes promoted inflammation and cytotoxicity on AC16 cardiomyocytes. Exogenous Cer16:0, Cer24:1, and palmitic acid reproduced deleterious effects in AC16 cells. These effects were attenuated by exogenous apoJ. Diabetic secretomes promoted inflammation and cytotoxicity in cardiomyocytes. This effect was exacerbated in the secretomes of the DM-C samples. The increased content of specific NEFA and ceramide species seems to play a key role in inducing such deleterious effects, which are attenuated by apoJ.

Effects of Achieving Rapid, Intensive, and Sustained Blood Pressure Reduction in Intracerebral Hemorrhage Expansion and Functional Outcome.

BACKGROUND AND OBJECTIVES: The time taken to achieve blood pressure (BP) control could be pivotal in the benefits of reducing BP in acute intracerebral hemorrhage (ICH). We aimed to assess the relationship between the rapid achievement and sustained maintenance of an intensive systolic BP (SBP) target with radiologic, clinical, and functional outcomes. METHODS: Rapid, Intensive, and Sustained BP lowering in Acute ICH (RAINS) was a multicenter, prospective, observational cohort study of adult patients with ICH <6 hours and SBP ≥150 mm Hg at 4 Comprehensive Stroke Centers during a 4.5-year period. Patients underwent baseline and 24-hour CT scans and 24-hour noninvasive BP monitoring. BP was managed under a rapid (target achievement ≤60 minutes), intensive (target SBP <140 mm Hg), and sustained (target stability for 24 hours) BP protocol. SBP target achievement ≤60 minutes and 24-hour SBP variability were recorded. Outcomes included hematoma expansion (>6 mL or >33%) at 24 hours (primary outcome), early neurologic deterioration (END, 24-hour increase in NIH Stroke Scale score ≥4), and 90-day ordinal modified Rankin scale (mRS) score. Analyses were adjusted by age, sex, anticoagulation, onset-to-imaging time, ICH volume, and intraventricular extension. RESULTS: We included 312 patients (mean age 70.2 ± 13.3 years, 202 [64.7%] male). Hematoma expansion occurred in 70/274 (25.6%) patients, END in 58/291 (19.9%), and the median 90-day mRS score was 4 (interquartile range, 2-5). SBP target achievement ≤60 minutes (178/312 [57.1%]) associated with a lower risk of hematoma expansion (adjusted odds ratio [aOR] 0.43, 95% confidence interval [CI] 0.23-0.77), lower END rate (aOR 0.43, 95% CI 0.23-0.80), and lower 90-day mRS scores (aOR 0.48, 95% CI 0.32-0.74). The mean 24-hour SBP variability was 21.0 ± 7.6 mm Hg. Higher 24-hour SBP variability was not related to expansion (aOR 0.99, 95% CI 0.95-1.04) but associated with higher END rate (aOR 1.15, 95% CI 1.09-1.21) and 90-day mRS scores (aOR 1.06, 95% CI 1.04-1.10). DISCUSSION: Among patients with acute ICH, achieving an intensive SBP target within 60 minutes was associated with lower hematoma expansion risk. Rapid SBP reduction and stable sustention within 24 hours were related to improved clinical and functional outcomes. These findings warrant the design of randomized clinical trials examining the impact of effectively achieving rapid, intensive, and sustained BP control on hematoma expansion. CLASSIFICATION OF EVIDENCE: This study provides Class III evidence that in adults with spontaneous ICH and initial SBP ≥150 mm Hg, lowering SBP to <140 mm Hg within the first hour and maintaining this for 24 hours is associated with decreased hematoma expansion.

Role of PATJ in stroke prognosis by modulating endothelial to mesenchymal transition through the Hippo/Notch/PI3K axis.

Through GWAS studies we identified PATJ associated with functional outcome after ischemic stroke (IS). The aim of this study was to determine PATJ role in brain endothelial cells (ECs) in the context of stroke outcome. PATJ expression analyses in patient's blood revealed that: (i) the risk allele of rs76221407 induces higher expression of PATJ, (ii) PATJ is downregulated 24 h after IS, and (iii) its expression is significantly lower in those patients with functional independence, measured at 3 months with the modified Rankin scale ((mRS) ≤2), compared to those patients with marked disability (mRS = 4-5). In mice brains, PATJ was also downregulated in the injured hemisphere at 48 h after ischemia. Oxygen-glucose deprivation and hypoxia-dependent of Hypoxia Inducible Factor-1α also caused PATJ depletion in ECs. To study the effects of PATJ downregulation, we generated PATJ-knockdown human microvascular ECs. Their transcriptomic profile evidenced a complex cell reprogramming involving Notch, TGF-ß, PI3K/Akt, and Hippo signaling that translates in morphological and functional changes compatible with endothelial to mesenchymal transition (EndMT). PATJ depletion caused loss of cell-cell adhesion, upregulation of metalloproteases, actin cytoskeleton remodeling, cytoplasmic accumulation of the signal transducer C-terminal transmembrane Mucin 1 (MUC1-C) and downregulation of Notch and Hippo signaling. The EndMT phenotype of PATJ-depleted cells was associated with the nuclear recruitment of MUC1-C, YAP/TAZ, ß-catenin, and ZEB1. Our results suggest that PATJ downregulation 24 h after IS promotes EndMT, an initial step prior to secondary activation of a pro-angiogenic program. This effect is associated with functional independence suggesting that activation of EndMT shortly after stroke onset is beneficial for stroke recovery.

Association of candidate genetic variants and circulating levels of ApoE/ApoJ with common neuroimaging features of cerebral amyloid angiopathy.

Introduction: Cerebral amyloid angiopathy (CAA) is characterized by the accumulation of amyloid-ß (Aß) in brain vessels and is a main cause of lobar intracerebral hemorrhage (ICH) in the elderly. CAA is associated with magnetic resonance imaging (MRI) markers of small vessel disease (SVD). Since Aß is also accumulated in Alzheimer's disease (AD) in the brain parenchyma, we aimed to study if several single nucleotide polymorphisms (SNPs) previously associated with AD were also associated with CAA pathology. Furthermore, we also studied the influence of APOE and CLU genetic variants in apolipoprotein E (ApoE) and clusterin/apolipoprotein J (ApoJ) circulating levels and their distribution among lipoproteins. Methods: The study was carried out in a multicentric cohort of 126 patients with lobar ICH and clinical suspicion of CAA. Results: We observed several SNPs associated with CAA neuroimaging MRI markers [cortical superficial siderosis (cSS), enlarged perivascular spaces in the centrum semiovale (CSO-EPVS), lobar cerebral microbleeds (CMB), white matter hyperintensities (WMH), corticosubcortical atrophy and CAA-SVD burden score]. Concretely, ABCA7 (rs3764650), CLU (rs9331896 and rs933188), EPHA1 (rs11767557), and TREML2 (rs3747742) were significantly associated with a CAA-SVD burden score. Regarding circulating levels of apolipoproteins, protective AD SNPs of CLU [rs11136000 (T) and rs9331896 (C)] were significantly associated with higher HDL ApoJ content in the lobar ICH cohort. APOEε2 carriers presented higher plasma and LDL-associated ApoE levels whereas APOEε4 carriers presented lower plasma ApoE levels. Additionally, we observed that lower circulating ApoJ and ApoE levels were significantly associated with CAA-related MRI markers. More specifically, lower LDL-associated ApoJ and plasma and HDL-associated ApoE levels were significantly associated with CSO-EPVS, lower ApoJ content in HDL with brain atrophy and lower ApoE content in LDL with the extent of cSS. Discussion: This study reinforces the relevance of lipid metabolism in CAA and cerebrovascular functionality. We propose that ApoJ and ApoE distribution among lipoproteins may be associated with pathological features related to CAA with higher ApoE and ApoJ levels in HDL possibly enhancing atheroprotective, antioxidative, and anti-inflammatory responses in cerebral ß-amyloidosis.

Therapeutic effect of human ApoA-I-Milano variant in aged transgenic mouse model of Alzheimer's disease.

BACKGROUND AND PURPOSE: Therapies based on apolipoprotein A-I (ApoA-I), classically tested for cardiovascular diseases, were recently proposed for Alzheimer's disease (AD). Based on a drug reprofiling approach, our objective was to explore the use of a natural variant of ApoA-I form, ApoA-I-Milano (M), as a treatment for AD. ApoA-I-M contains the R173C mutation, and confers protection against atherosclerosis development, although ApoA-I-M carriers exhibit low HDL levels. EXPERIMENTAL APPROACH: Middle-aged (12-month-old) and aged (21-month-old) APP23 mice were intraperitoneally treated for 10 weeks with human recombinant ApoA-I-M (hrApoA-I-M) protein or saline. Pathology progression through behavioural parameters and biochemical determinations was evaluated. KEY RESULTS: In middle-aged group, hrApoA-I-M treatment reduced the anxiety behaviour associated with this AD model. In aged mice, hrApoA-I-M reversed T-Maze performance alterations, a cognitive improvement accompanied by neuronal loss recovery in the dentate gyrus. Aged mice treated with hrApoA-I-M showed lower brain Aß40 soluble levels and elevated Aß40 levels in cerebrospinal fluid, without modifying insoluble brain Aß burden. Interestingly, hrApoA-I-M sub-chronic treatment induced a molecular effect on the cerebrovasculature, increasing occludin expression and ICAM-1 presence, as well as promoting an elevation of plasma soluble RAGE in all hrApoA-I-M-treated mice, drastically decreasing the AGEs/sRAGE ratio, a marker of endothelial damage. CONCLUSION AND IMPLICATIONS: Peripheral hrApoA-I-M treatment shows a beneficial impact on working memory, involving mechanisms related with brain Aß mobilization and modulation of the levels of cerebrovascular markers. Our study shows the potential therapeutic applicability of a safe and non-invasive treatment based on peripheral administration of hrApoA-I-M in AD.

The Boston criteria version 2.0 for cerebral amyloid angiopathy: a multicentre, retrospective, MRI-neuropathology diagnostic accuracy study.

BACKGROUND: Cerebral amyloid angiopathy (CAA) is an age-related small vessel disease, characterised pathologically by progressive deposition of amyloid ß in the cerebrovascular wall. The Boston criteria are used worldwide for the in-vivo diagnosis of CAA but have not been updated since 2010, before the emergence of additional MRI markers. We report an international collaborative study aiming to update and externally validate the Boston diagnostic criteria across the full spectrum of clinical CAA presentations. METHODS: In this multicentre, hospital-based, retrospective, MRI and neuropathology diagnostic accuracy study, we did a retrospective analysis of clinical, radiological, and histopathological data available to sites participating in the International CAA Association to formulate updated Boston criteria and establish their diagnostic accuracy across different populations and clinical presentations. Ten North American and European academic medical centres identified patients aged 50 years and older with potential CAA-related clinical presentations (ie, spontaneous intracerebral haemorrhage, cognitive impairment, or transient focal neurological episodes), available brain MRI, and histopathological assessment for CAA diagnosis. MRI scans were centrally rated at Massachusetts General Hospital (Boston, MA, USA) for haemorrhagic and non-haemorrhagic CAA markers, and brain tissue samples were rated by neuropathologists at the contributing sites. We derived the Boston criteria version 2.0 (v2.0) by selecting MRI features to optimise diagnostic specificity and sensitivity in a prespecified derivation cohort (Boston cases 1994-2012, n=159), then externally validated the criteria in a prespecified temporal validation cohort (Boston cases 2012-18, n=59) and a geographical validation cohort (non-Boston cases 2004-18; n=123), comparing accuracy of the new criteria to the currently used modified Boston criteria with histopathological assessment of CAA as the diagnostic standard. We also assessed performance of the v2.0 criteria in patients across all cohorts who had the diagnostic gold standard of brain autopsy. FINDINGS: The study protocol was finalised on Jan 15, 2017, patient identification was completed on Dec 31, 2018, and imaging analyses were completed on Sept 30, 2019. Of 401 potentially eligible patients presenting to Massachusetts General Hospital, 218 were eligible to be included in the analysis; of 160 patient datasets from other centres, 123 were included. Using the derivation cohort, we derived provisional criteria for probable CAA requiring the presence of at least two strictly lobar haemorrhagic lesions (ie, intracerebral haemorrhages, cerebral microbleeds, or foci of cortical superficial siderosis) or at least one strictly lobar haemorrhagic lesion and at least one white matter characteristic (ie, severe visible perivascular spaces in centrum semiovale or white matter hyperintensities in a multispot pattern). The sensitivity and specificity of these criteria were 74·8% (95% CI 65·4-82·7) and 84·6% (71·9-93·1) in the derivation cohort, 92·5% (79·6-98·4) and 89·5% (66·9-98·7) in the temporal validation cohort, 80·2% (70·8-87·6) and 81·5% (61·9-93·7) in the geographical validation cohort, and 74·5% (65·4-82·4) and 95·0% (83·1-99·4) in all patients who had autopsy as the diagnostic standard. The area under the receiver operating characteristic curve (AUC) was 0·797 (0·732-0·861) in the derivation cohort, 0·910 (0·828-0·992) in the temporal validation cohort, 0·808 (0·724-0·893) in the geographical validation cohort, and 0·848 (0·794-0·901) in patients who had autopsy as the diagnostic standard. The v2.0 Boston criteria for probable CAA had superior accuracy to the current Boston criteria (sensitivity 64·5% [54·9-73·4]; specificity 95·0% [83·1-99·4]; AUC 0·798 [0·741-0854]; p=0·0005 for comparison of AUC) across all individuals who had autopsy as the diagnostic standard. INTERPRETATION: The Boston criteria v2.0 incorporate emerging MRI markers of CAA to enhance sensitivity without compromising their specificity in our cohorts of patients aged 50 years and older presenting with spontaneous intracerebral haemorrhage, cognitive impairment, or transient focal neurological episodes. Future studies will be needed to determine generalisability of the v.2.0 criteria across the full range of patients and clinical presentations. FUNDING: US National Institutes of Health (R01 AG26484).

Impact of Cerebral Amyloid Angiopathy in Two Transgenic Mouse Models of Cerebral ß-Amyloidosis: A Neuropathological Study.

The pathological accumulation of parenchymal and vascular amyloid-beta (Aß) are the main hallmarks of Alzheimer's disease (AD) and Cerebral Amyloid Angiopathy (CAA), respectively. Emerging evidence raises an important contribution of vascular dysfunction in AD pathology that could partially explain the failure of anti-Aß therapies in this field. Transgenic mice models of cerebral ß-amyloidosis are essential to a better understanding of the mechanisms underlying amyloid accumulation in the cerebrovasculature and its interactions with neuritic plaque deposition. Here, our main objective was to evaluate the progression of both parenchymal and vascular deposition in APP23 and 5xFAD transgenic mice in relation to age and sex. We first showed a significant age-dependent accumulation of extracellular Aß deposits in both transgenic models, with a greater increase in APP23 females. We confirmed that CAA pathology was more prominent in the APP23 mice, demonstrating a higher progression of Aß-positive vessels with age, but not linked to sex, and detecting a pronounced burden of cerebral microbleeds (cMBs) by magnetic resonance imaging (MRI). In contrast, 5xFAD mice did not present CAA, as shown by the negligible Aß presence in cerebral vessels and the occurrence of occasional cMBs comparable to WT mice. In conclusion, the APP23 mouse model is an interesting tool to study the overlap between vascular and parenchymal Aß deposition and to evaluate future disease-modifying therapy before its translation to the clinic.

Association of CD2AP neuronal deposits with Braak neurofibrillary stage in Alzheimer's disease.

Genome-wide association studies have described several genes as genetic susceptibility loci for Alzheimer's disease (AD). Among them, CD2AP encodes CD2-associated protein, a scaffold protein implicated in dynamic actin remodeling and membrane trafficking during endocytosis and cytokinesis. Although a clear link between CD2AP defects and glomerular pathology has been described, little is known about the function of CD2AP in the brain. The aim of this study was to analyze the distribution of CD2AP in the AD brain and its potential associations with tau aggregation and ß-amyloid (Aß) deposition. First, we performed immunohistochemical analysis of CD2AP expression in brain tissue from AD patients and controls (N = 60). Our results showed granular CD2AP immunoreactivity in the human brain endothelium in all samples. In AD cases, no CD2AP was found to be associated with Aß deposits in vessels or parenchymal plaques. CD2AP neuronal inclusions similar to neurofibrillary tangles (NFT) and neuropil thread-like deposits were found only in AD samples. Moreover, immunofluorescence analysis revealed that CD2AP colocalized with pTau. Regarding CD2AP neuronal distribution, a hierarchical progression from the entorhinal to the temporal and occipital cortex was detected. We found that CD2AP immunodetection in neurons was strongly and positively associated with Braak neurofibrillary stage, independent of age and other pathological hallmarks. To further investigate the association between pTau and CD2AP, we included samples from cases of primary tauopathies (corticobasal degeneration [CBD], progressive supranuclear palsy [PSP], and Pick's disease [PiD]) in our study. Among these cases, CD2AP positivity was only found in PiD samples as neurofibrillary tangle-like and Pick body-like deposits, whereas no neuronal CD2AP deposits were detected in PSP or CBD samples, which suggested an association of CD2AP neuronal expression with 3R-Tau-diseases. In conclusion, our findings open a new road to investigate the complex cellular mechanism underlying the tangle conformation and tau pathology in the brain.

MFG-E8 (LACTADHERIN): a novel marker associated with cerebral amyloid angiopathy.

Brain accumulation of amyloid-beta (Aß) is a crucial feature in Alzheimer´s disease (AD) and cerebral amyloid angiopathy (CAA), although the pathophysiological relationship between these diseases remains unclear. Numerous proteins are associated with Aß deposited in parenchymal plaques and/or cerebral vessels. We hypothesized that the study of these proteins would increase our understanding of the overlap and biological differences between these two pathologies and may yield new diagnostic tools and specific therapeutic targets. We used a laser capture microdissection approach combined with mass spectrometry in the APP23 transgenic mouse model of cerebral-ß-amyloidosis to specifically identify vascular Aß-associated proteins. We focused on one of the main proteins detected in the Aß-affected cerebrovasculature: MFG-E8 (milk fat globule-EGF factor 8), also known as lactadherin. We first validated the presence of MFG-E8 in mouse and human brains. Immunofluorescence and immunoblotting studies revealed that MFG-E8 brain levels were higher in APP23 mice than in WT mice. Furthermore, MFG-E8 was strongly detected in Aß-positive vessels in human postmortem CAA brains, whereas MFG-E8 was not present in parenchymal Aß deposits. Levels of MFG-E8 were additionally analysed in serum and cerebrospinal fluid (CSF) from patients diagnosed with CAA, patients with AD and control subjects. Whereas no differences were found in MFG-E8 serum levels between groups, MFG-E8 concentration was significantly lower in the CSF of CAA patients compared to controls and AD patients. Finally, in human vascular smooth muscle cells MFG-E8 was protective against the toxic effects of the treatment with the Aß40 peptide containing the Dutch mutation. In summary, our study shows that MFG-E8 is highly associated with CAA pathology and highlights MFG-E8 as a new CSF biomarker that could potentially be used to differentiate cerebrovascular Aß pathology from parenchymal Aß deposition.

Survival Bias and Crosstalk between Chronological and Behavioral Age: Age- and Genotype-Sensitivity Tests Define Behavioral Signatures in Middle-Aged, Old, and Long-Lived Mice with Normal and AD-Associated Aging.

New evidence refers to a high degree of heterogeneity in normal but also Alzheimer's disease (AD) clinical and temporal patterns, increased mortality, and the need to find specific end-of-life prognosticators. This heterogeneity is scarcely explored in very old male AD mice models due to their reduced survival. In the present work, using 915 (432 APP23 and 483 C57BL/6 littermates) mice, we confirmed the better survival curves in male than female APP23 mice and respective wildtypes, providing the chance to characterize behavioral signatures in middle-aged, old, and long-lived male animals. The sensitivity of a battery of seven paradigms for comprehensive screening of motor (activity and gait analysis), neuropsychiatric and cognitive symptoms was analyzed using a cohort of 56 animals, composed of 12-, 18- and 24-month-old male APP23 mice and wildtype littermates. Most variables analyzed detected age-related differences. However, variables related to coping with stress, thigmotaxis, frailty, gait, and poor cognition better discriminated the behavioral phenotype of male APP23 mice through the three old ages compared with controls. Most importantly, non-linear age- and genotype-dependent behavioral signatures were found in long-lived animals, suggesting crosstalk between chronological and biological/behavioral ages useful to study underlying mechanisms and distinct compensations through physiological and AD-associated aging.

New candidate blood biomarkers potentially associated with white matter hyperintensities progression.

We aimed to discover blood biomarkers associated with longitudinal changes in white matter hyperintensities (WMH). This study was divided into a discovery phase and a replication phase. Subjects in both studies were patients with hypertension, aged 50-70, who underwent two magnetic resonance imaging (MRI) sessions and blood extractions over a 4-year follow-up period. In the discovery phase, we screened 1305 proteins in 12 subjects with WMH progression and in 12 matched control subjects. We found that 41 proteins were differentially expressed: 13 were upregulated and 28 were downregulated. We subsequently selected three biomarkers for replication in baseline and follow-up samples in 80 subjects with WMH progression and in 80 control subjects. The selected protein candidates for the replication were MMP9 (matrix metalloproteinase-9), which was higher in cases, MET (hepatocyte growth factor receptor) and ASAH2 (neutral ceramidase), which were both lower in cases of WMH progression. Baseline biomarker concentrations did not predict WMH progression. In contrast, patients with WMH progression presented a steeper decline in MET over time. Furthermore, cases showed higher MMP9 and lower ASAH2 levels than controls at the follow-up. These results indicate that MMP9, MET, and ASAH2 are potentially associated with the progression of WMH, and could therefore be interesting candidates to validate in future studies.

Circulating AQP4 Levels in Patients with Cerebral Amyloid Angiopathy-Associated Intracerebral Hemorrhage.

Cerebral amyloid angiopathy (CAA) is a major cause of lobar intracerebral hemorrhage (ICH) in elderly patients. Growing evidence suggests a potential role of aquaporin 4 (AQP4) in amyloid-beta-associated diseases, including CAA pathology. Our aim was to investigate the circulating levels of AQP4 in a cohort of patients who had suffered a lobar ICH with a clinical diagnosis of CAA. AQP4 levels were analyzed in the serum of 60 CAA-related ICH patients and 19 non-stroke subjects by enzyme-linked immunosorbent assay (ELISA). The CAA-ICH cohort was divided according to the time point of the functional outcome evaluation: mid-term (12 ± 18.6 months) and long-term (38.5 ± 32.9 months) after the last ICH. Although no differences were found in AQP4 serum levels between cases and controls, lower levels were found in CAA patients presenting specific hemorrhagic features such as ≥2 lobar ICHs and ≥5 lobar microbleeds detected by magnetic resonance imaging (MRI). In addition, CAA-related ICH patients who presented a long-term good functional outcome had higher circulating AQP4 levels than subjects with a poor outcome or controls. Our data suggest that AQP4 could potentially predict a long-term functional outcome and may play a protective role after a lobar ICH.

SSAO/VAP-1 in Cerebrovascular Disorders: A Potential Therapeutic Target for Stroke and Alzheimer's Disease.

The semicarbazide-sensitive amine oxidase (SSAO), also known as vascular adhesion protein-1 (VAP-1) or primary amine oxidase (PrAO), is a deaminating enzyme highly expressed in vessels that generates harmful products as a result of its enzymatic activity. As a multifunctional enzyme, it is also involved in inflammation through its ability to bind and promote the transmigration of circulating leukocytes into inflamed tissues. Inflammation is present in different systemic and cerebral diseases, including stroke and Alzheimer's disease (AD). These pathologies show important affectations on cerebral vessels, together with increased SSAO levels. This review summarizes the main roles of SSAO/VAP-1 in human physiology and pathophysiology and discusses the mechanisms by which it can affect the onset and progression of both stroke and AD. As there is an evident interrelationship between stroke and AD, basically through the vascular system dysfunction, the possibility that SSAO/VAP-1 could be involved in the transition between these two pathologies is suggested. Hence, its inhibition is proposed to be an interesting therapeutical approach to the brain damage induced in these both cerebral pathologies.

Comparison of Plasma Lipoprotein Composition and Function in Cerebral Amyloid Angiopathy and Alzheimer's Disease.

Cerebral amyloid angiopathy (CAA) refers to beta-amyloid (Aß) deposition in brain vessels and is clinically the main cause of lobar intracerebral hemorrhage (ICH). Aß can also accumulate in brain parenchyma forming neuritic plaques in Alzheimer's disease (AD). Our study aimed to determine whether the peripheral lipid profile and lipoprotein composition are associated with cerebral beta-amyloidosis pathology and may reflect biological differences in AD and CAA. For this purpose, lipid and apolipoproteins levels were analyzed in plasma from 51 ICH-CAA patients (collected during the chronic phase of the disease), 60 AD patients, and 60 control subjects. Lipoproteins (VLDL, LDL, and HDL) were isolated and their composition and pro/antioxidant ability were determined. We observed that alterations in the lipid profile and lipoprotein composition were remarkable in the ICH-CAA group compared to control subjects, whereas the AD group presented no specific alterations compared with controls. ICH-CAA patients presented an atheroprotective profile, which consisted of lower total and LDL cholesterol levels. Plasma from chronic ICH-CAA patients also showed a redistribution of ApoC-III from HDL to VLDL and a higher ApoE/ApoC-III ratio in HDL. Whether these alterations reflect a protective response or have a causative effect on the pathology requires further investigation.

Circulating TIMP-1 is associated with hematoma volume in patients with spontaneous intracranial hemorrhage.

Matrix metalloproteinases (MMPs) are proteolytic zinc-endopeptidases regulated by tissue Inhibitors of matrix metalloproteinases (TIMPs). We evaluated the potential of MMPs and TIMPs as clinical tools for Intracranial Haemorrhage (ICH). Spontaneous non-traumatic ICH patients were recruited from two hospitals: Complejo Hospitalario de Navarra (CHN = 29) and Vall d´Hebron (VdH = 76). Plasmatic levels of MMP-1, -2, -7, -9, -10 and TIMP-1 and their relationship with clinical, radiological and functional variables were evaluated. We further studied the effect of TIMP-1 (0.05-0.2 mg/Kg) in an experimental tail-bleeding model. In CHN, TIMP-1 was associated with admission-hematoma volume and MMP-7 was elevated in patients with deep when compared to lobar hematoma. In VdH, admission-hematoma volume was associated with TIMP-1 and MMP-7. When data from both hospitals were combined, we observed that an increase in 1 ng/ml in TIMP-1 was associated with an increase of 0.14 ml in haemorrhage (combined ß = 0.14, 95% CI = 0.08-0.21). Likewise, mice receiving TIMP-1 (0.2 mg/Kg) showed a shorter bleeding time (p < 0.01). Therefore, the association of TIMP-1 with hematoma volume in two independent ICH cohorts suggests its potential as ICH biomarker. Moreover, increased TIMP-1 might not be sufficient to counterbalance MMPs upregulation indicating that TIMP-1 administration might be a beneficial strategy for ICH.

CCL23: A Chemokine Associated with Progression from Mild Cognitive Impairment to Alzheimer's Disease.

CCL23 is a chemokine implicated in inflammation and host defense responses. It has been recently associated with acquired brain damage and stroke outcomes. In this study, we reported the role of CCL23 in Alzheimer's disease (AD). We evaluated the levels of CCL23 in 659 individuals: cognitively normal, mild cognitive impaired (MCI), and AD patients. Two cross-sectional (study 1, n = 53; study 2, n = 200) and two longitudinal (study 3, n = 74; study 4, n = 332) studies were analyzed separately. CCL23 levels in the blood and/or cerebrospinal fluid (CSF) of each study were measured by immunoassays. Globally, our results suggest a predictive role of CCL23 protein levels both in the plasma in study 3 (hazard ratio (HR) = 2.5 (confidence interval (CI) 95% : 1.2-5.3), p = 0.02) and in the CSF in study 4 (HR = 3.05 (CI 95% : 1.02-5), p = 0.04) in cases of MCI that progress to AD. Moreover, we observed that the APOEɛ4 allele was associated with higher levels of CCL23 in study 2 (470.33 pg/mL (interquartile range (IQR): 303.33-597.76) versus 377.94 pg/mL (IQR: 267.16-529.19), p = 0.01) (APOE genotypes were available in studies 2 and 4). Together, these findings support the role of CCL23 in neuroinflammation in the early stages of AD, suggesting that CCL23 might be a candidate blood biomarker for MCI to AD progression.

Cerebral amyloid angiopathy and Alzheimer disease - one peptide, two pathways.

The shared role of amyloid-ß (Aß) deposition in cerebral amyloid angiopathy (CAA) and Alzheimer disease (AD) is arguably the clearest instance of crosstalk between neurodegenerative and cerebrovascular processes. The pathogenic pathways of CAA and AD intersect at the levels of Aß generation, its circulation within the interstitial fluid and perivascular drainage pathways and its brain clearance, but diverge in their mechanisms of brain injury and disease presentation. Here, we review the evidence for and the pathogenic implications of interactions between CAA and AD. Both pathologies seem to be driven by impaired Aß clearance, creating conditions for a self-reinforcing cycle of increased vascular Aß, reduced perivascular clearance and further CAA and AD progression. Despite the close relationship between vascular and plaque Aß deposition, several factors favour one or the other, such as the carboxy-terminal site of the peptide and specific co-deposited proteins. Amyloid-related imaging abnormalities that have been seen in trials of anti-Aß immunotherapy are another probable intersection between CAA and AD, representing overload of perivascular clearance pathways and the effects of removing Aß from CAA-positive vessels. The intersections between CAA and AD point to a crucial role for improving vascular function in the treatment of both diseases and indicate the next steps necessary for identifying therapies.

Advancing diagnostic criteria for sporadic cerebral amyloid angiopathy: Study protocol for a multicenter MRI-pathology validation of Boston criteria v2.0.

RATIONALE: The Boston criteria are used worldwide for the in vivo diagnosis of cerebral amyloid angiopathy and are the basis for clinical decision-making and research in the field. Given substantial advances in cerebral amyloid angiopathy's clinical aspects and MRI biomarkers, we designed a multicenter study within the International cerebral amyloid angiopathy Association aimed at further validating the diagnostic accuracy of the Boston and potentially improving and updating them. AIM: We aim to derive and validate an updated "version 2.0" of the Boston criteria across the spectrum of cerebral amyloid angiopathy-related presentations and MRI biomarkers. SAMPLE SIZE ESTIMATES: Participating centers with suitable available data (see Methods) were identified from existing collaborations and an open invitation to the International Cerebral Amyloid Angiopathy Association emailing list. Our study sample will include: (1) a derivation cohort - Massachusetts General Hospital (MGH), Boston cases from inception to 2012 (∼150 patients); (2) temporal external validation cohort - MGH, Boston cases from 2012 to 2018 (∼100 patients); and (3) geographical external validation cohort - non-Boston cases (∼85 patients). METHODS AND DESIGN: Multicenter collaborative study. We will collect and analyze data from patients' age ≥ 50 with any potential sporadic cerebral amyloid angiopathy-related clinical presentations (spontaneous intracerebral hemorrhage, transient focal neurological episodes and cognitive impairment), available brain MRI ("index test"), and histopathologic assessment for cerebral amyloid angiopathy ("reference standard" for diagnosis). Trained raters will assess MRI for all prespecified hemorrhagic and non-hemorrhagic small vessel disease markers of interest, according to validated criteria and a prespecified protocol, masked to clinical and histopathologic features. Brain tissue samples will be rated for cerebral amyloid angiopathy, defined as Vonsattel grade ≥2 for whole brain autopsies and ≥1 for cortical biopsies or hematoma evacuation. Based on our estimated available sample size, we will undertake pre-specified cohort splitting as above. We will: (a) pre-specify variables and statistical cut-offs; (b) examine univariable and multivariable associations; and (c) then assess classification measures (sensitivity, specificity etc.) for each MRI biomarker individually, in relation to the cerebral amyloid angiopathy diagnosis reference standard on neuropathology in a derivation cohort. The MRI biomarkers strongly associated with cerebral amyloid angiopathy diagnosis will be selected for inclusion in provisional (probable and possible cerebral amyloid angiopathy) Boston criteria v2.0 and validated using appropriate metrics and models. STUDY OUTCOMES: Boston criteria v2.0 for clinical cerebral amyloid angiopathy diagnosis. DISCUSSION: This work aims to potentially update and improve the diagnostic test accuracy of the Boston criteria for cerebral amyloid angiopathy and to provide wider validation of the criteria in a large sample. We envision that this work will meet the needs of clinicians and investigators and help accelerate progress towards better treatment of cerebral amyloid angiopathy.