Maged D. Fam

Quantitative Susceptibility Mapping in Cerebral Cavernous Malformations: Clinical Correlations.

BACKGROUND AND PURPOSE: Quantitative susceptibility mapping has been shown to assess iron content in cerebral cavernous malformations. In this study, our aim was to correlate lesional iron deposition assessed by quantitative susceptibility mapping with clinical and disease features in patients with cerebral cavernous malformations. MATERIALS AND METHODS: Patients underwent routine clinical scans in addition to quantitative susceptibility mapping on 3T systems. Data from 105 patients met the inclusion criteria. Cerebral cavernous malformation lesions identified on susceptibility maps were cross-verified by T2-weighted images and differentiated on the basis of prior overt hemorrhage. Mean susceptibility per cerebral cavernous malformation lesion (χ̄lesion) was measured to correlate with lesion volume, age at scanning, and hemorrhagic history. Temporal rates of change in χ̄lesion were evaluated in 33 patients. RESULTS: Average χ̄lesion per patient was positively correlated with patient age at scanning (P < .05, 4.1% change with each decade of life). Cerebral cavernous malformation lesions with prior overt hemorrhages exhibited higher χ̄lesion than those without (P < .05). Changes in χ̄lesion during 3- to 15-month follow-up were small in patients without new hemorrhage between the 2 scans (bias = −0.0003; 95% CI, −0.06–0.06). CONCLUSIONS: The study revealed a positive correlation between mean quantitative susceptibility mapping signal and patient age in cerebral cavernous malformation lesions, higher mean quantitative susceptibility mapping signal in hemorrhagic lesions, and minimum longitudinal quantitative susceptibility mapping signal change in clinically stable lesions. Quantitative susceptibility mapping has the potential to be a novel imaging biomarker supplementing conventional imaging in cerebral cavernous malformations. The clinical significance of such measures merits further study.

Peripheral plasma vitamin D and non-HDL cholesterol reflect the severity of cerebral cavernous malformation disease

AIM To correlate cerebral cavernous malformations (CCMs) disease aggressiveness with peripheral blood biomarkers hypothesized mechanistically. PATIENTS & METHODS A prospective case-control study enrolled 43 CCM patients, where 25-(OH) vitamin D, HDL and non-HDL cholesterol, CRP plasma levels and leukocyte ROCK activity were correlated with parameters of disease aggressiveness reflecting chronic and acute domains. RESULTS Patients with one or more features of chronically aggressive disease (early age at symptom onset, two or more symptomatic bleeds, high lesion burden) had significantly lower 25-(OH) vitamin D and non-HDL cholesterol levels in comparison to patients without these features. CONCLUSION Validation of these biomarkers and their potential treatment modulation may influence the clinical care of patients with CCM disease.

Vascular permeability and iron deposition biomarkers in longitudinal follow-up of cerebral cavernous malformations

OBJECTIVE Vascular permeability and iron leakage are central features of cerebral cavernous malformation (CCM) pathogenesis. The authors aimed to correlate prospective clinical behavior of CCM lesions with longitudinal changes in biomarkers of dynamic contrast-enhanced quantitative permeability (DCEQP) and quantitative susceptibility mapping (QSM) assessed by MRI. METHODS Forty-six patients with CCMs underwent 2 or more permeability and/or susceptibility studies in conjunction with baseline and follow-up imaging and clinical surveillance during a mean 12.05 months of follow-up (range 2.4-31.27 months). Based on clinical and imaging features, cases/lesions were classified as stable, unstable, or recovering. Associated and predictive changes in quantitative permeability and susceptibility were investigated. RESULTS Lesional mean permeability and QSM values were not significantly different in stable versus unstable lesions at baseline. Mean lesional permeability in unstable CCMs with lesional bleeding or growth increased significantly (+85.9% change; p = 0.005), while mean permeability in stable and recovering lesions did not significantly change. Mean lesional QSM values significantly increased in unstable lesions (+44.1% change; p = 0.01), decreased slightly with statistical significance in stable lesions (-3.2% change; p = 0.003), and did not significantly change in recovering lesions. Familial cases developing new lesions during the follow-up period showed a higher background brain permeability at baseline (p = 0.001), as well as higher regional permeability (p = 0.003) in the area that would later develop a new lesion as compared with the homologous contralateral brain region. CONCLUSIONS In vivo assessment of vascular permeability and iron deposition on MRI can serve as objective and quantifiable biomarkers of disease activity in CCMs. This may be applied in natural history studies and may help calibrate clinical trials. The 2 techniques are likely applicable in other disorders of vascular integrity and iron leakage such as aging, hemorrhagic microangiopathy, and traumatic brain injury.

Micro-computed tomography in murine models of cerebral cavernous malformations as a paradigm for brain disease.

BACKGROUND Cerebral cavernous malformations (CCMs) are hemorrhagic brain lesions, where murine models allow major mechanistic discoveries, ushering genetic manipulations and preclinical assessment of therapies. Histology for lesion counting and morphometry is essential yet tedious and time consuming. We herein describe the application and validations of X-ray micro-computed tomography (micro-CT), a non-destructive technique allowing three-dimensional CCM lesion count and volumetric measurements, in transgenic murine brains. NEW METHOD We hereby describe a new contrast soaking technique not previously applied to murine models of CCM disease. Volumetric segmentation and image processing paradigm allowed for histologic correlations and quantitative validations not previously reported with the micro-CT technique in brain vascular disease. RESULTS Twenty-two hyper-dense areas on micro-CT images, identified as CCM lesions, were matched by histology. The inter-rater reliability analysis showed strong consistency in the CCM lesion identification and staging (K=0.89, p<0.0001) between the two techniques. Micro-CT revealed a 29% greater CCM lesion detection efficiency, and 80% improved time efficiency. COMPARISON WITH EXISTING METHOD Serial integrated lesional area by histology showed a strong positive correlation with micro-CT estimated volume (r(2)=0.84, p<0.0001). CONCLUSIONS Micro-CT allows high throughput assessment of lesion count and volume in pre-clinical murine models of CCM. This approach complements histology with improved accuracy and efficiency, and can be applied for lesion burden assessment in other brain diseases.

B-Cell Depletion Reduces the Maturation of Cerebral Cavernous Malformations in Murine Models

Cerebral cavernous malformations (CCMs) are relatively common vascular malformations, characterized by increased Rho kinase (ROCK) activity, vascular hyper-permeability and the presence of blood degradation products including non-heme iron. Previous studies revealed robust inflammatory cell infiltration, selective synthesis of IgG, in situ antigen driven B-cell clonal expansion, and deposition of immune complexes and complement proteins within CCM lesions. We aimed to evaluate the impact of suppressing the immune response on the formation and maturation of CCM lesions, as well as lesional iron deposition and ROCK activity. Two murine models of heterozygous Ccm3 (Pdcd10), which spontaneously develop CCM lesions with severe and milder phenotypes, were either untreated or received anti-mouse BR3 to deplete B cells. Brains from anti-mouse BR3-treated mice exhibited significantly fewer mature CCM lesions and smaller lesions compared to untreated mice. B cell depletion halted the progression of lesions into mature stage 2 lesions but did not prevent their genesis. Non-heme iron deposition and ROCK activity was decreased in lesions of B cell depleted mice. This represents the first report of the therapeutic benefit of B-cell depletion in the development and progression of CCMs, and provides a proof of principle that B cells play a critical role in CCM lesion genesis and maturation. These findings add biologics to the list of potential therapeutic agents for CCM disease. Future studies would characterize the putative antigenic trigger and further define the mechanism of immune response in the lesions.

CSF inflammatory response after intraventricular hemorrhage

Objective: To investigate the temporal pattern and relevant associations of CSF inflammatory measures after intraventricular hemorrhage (IVH). Methods: We analyzed prospectively collected CSF cell counts and protein and glucose levels from participants in the Clot Lysis Evaluation of Accelerated Resolution of IVH phase III (CLEAR III) trial. Corrected leukocyte count and cell index were calculated to adjust for CSF leukocytes attributable to circulating blood. Data were chronologically plotted. CSF inflammatory measures (daily, mean, median, maximum, and cases with highest quartile response) were correlated with initial IVH volume, IVH clearance rate, thrombolytic treatment, bacterial infection, and adjudicated clinical outcome at 30 and 180 days. Results: A total of 11,376 data points of CSF results from 464 trial participants were analyzed. Measures of CSF inflammatory response evolved during the resolution of IVH. This was significantly more pronounced with initial IVH volume exceeding 20 mL. Intraventricular alteplase was associated with a significantly augmented inflammatory response compared to saline, even after correcting for initial IVH volume. There was an association but nonpredictive correlation of CSF inflammation measures with culture-positive CSF bacterial infection. None of the CSF inflammatory measures, including cases with upper quartile inflammatory response, was associated with a significant detrimental effect on 30 or 180 days functional outcome or mortality after multivariate adjustment for measures of disease severity. Conclusions: Aseptic CSF inflammation after IVH is primarily dependent on the volume of initial bleed. Thrombolysis intensifies the inflammatory response, with no apparent detrimental effect on clinical outcome. Clinicaltrials.gov identifier: NCT00784134.

Demographic Risk Factors for Vascular Lesions as Etiology of Intraventricular Hemorrhage in Prospectively Screened Cases

Background: Spontaneous intraventricular hemorrhage (IVH) is associated with high rates of morbidity and mortality despite critical care and other advances. An important step in clinical management is to confirm/rule out an underlying vascular lesion, which influences further treatment, potential for further bleeding, and prognosis. Our aim is to compare demographic and clinical characteristics between IVH patients with and without an underlying vascular lesion, and among cohorts with different vascular lesions. Methods: We analyzed prospectively collected data of IVH patients screened for eligibility as part of the Clot Lysis: Evaluation Accelerated Resolution of IVH Phase III (CLEAR III) clinical trial. The trial adopted a structured screening process to systematically exclude patients with an underlying vascular lesion as the etiology of IVH. We collected age, sex, ethnicity, and primary diagnosis on these cases and vascular lesions were categorized prospectively as aneurysm, vascular malformation (arteriovenous malformation, dural arteriovenous fistula, and cavernoma), Moyamoya disease, or other vascular lesion. We excluded cases <18 or >80 years of age. Baseline characteristics were compared between the CLEAR group (IVH screened without vascular lesion) and the group of IVH patients screened and excluded from CLEAR because of an identified vascular lesion. We further analyzed the differential demographic and clinical characteristics among subcohorts with different vascular lesions. Results: A total of 10,538 consecutive IVH cases were prospectively screened for the trial between 2011 and 2015. Out of these, 496 cases (4.7%) screened negative for underlying vascular lesion, met the inclusion criteria, and were enrolled in the trial (no vascular etiology group); and 1,205 cases (11.4%) were concurrently screened and excluded from the trial because of a demonstrated underlying vascular lesion (vascular etiology group). Cases with vascular lesion were less likely to be >45 years of age (OR 0.28, 95% CI 0.20-0.40), African-American (OR 0.23, 95% CI 0.18-0.31), or male gender (OR 0.48, 95% CI 0.38-0.60), and more likely to present with primary IVH (OR 1.85, 95% CI 1.37-2.51) compared to those with no vascular etiology (p < 0.001). Other demographic factors were associated with specific vascular lesion etiologies. A combination of demographic features increases the association with the absence of vascular lesion, but not with absolute reliability (OR 0.1, 95% CI 0.06-0.17, p < 0.001). Conclusion: An underlying vascular lesion as etiology of IVH cannot be excluded solely by demographic parameters in any patient. Some form of vascular imaging is necessary in screening patients before contemplating interventions like intraventricular fibrinolysis, where safety may be impacted by the presence of vascular lesion.

Phenotypic characterization of murine models of cerebral cavernous malformations

Cerebral cavernous malformations (CCMs) are clusters of dilated capillaries that affect around 0.5% of the population. CCMs exist in two forms, sporadic and familial. Mutations in three documented genes, KRIT1(CCM1), CCM2, and PDCD10(CCM3), cause the autosomal dominant form of the disease, and somatic mutations in these same genes underlie lesion development in the brain. Murine models with constitutive or induced loss of respective genes have been applied to study disease pathobiology and therapeutic manipulations. We aimed to analyze the phenotypic characteristic of two main groups of models, the chronic heterozygous models with sensitizers promoting genetic instability, and the acute neonatal induced homozygous knockout model. Acute model mice harbored a higher lesion burden than chronic models, more localized in the hindbrain, and largely lacking iron deposition and inflammatory cell infiltrate. The chronic model mice showed a lower lesion burden localized throughout the brain, with significantly greater perilesional iron deposition, immune B- and T-cell infiltration, and less frequent junctional protein immunopositive endothelial cells. Lesional endothelial cells in both models expressed similar phosphorylated myosin light chain immunopositivity indicating Rho-associated protein kinase activity. These data suggest that acute models are better suited to study the initial formation of the lesion, while the chronic models better reflect lesion maturation, hemorrhage, and inflammatory response, relevant pathobiologic features of the human disease.Cerebral cavernous malformations (CCMs) are clusters of dilated capillaries affecting around 0.5% of the population. The authors analyzed the phenotypic characteristics of chronic and acute murine models of CCM. The acute model harbored higher lesion burden while the chronic model showed more inflammation and lesional iron deposition.

Quantitative susceptibility mapping as a monitoring biomarker in cerebral cavernous malformations with recent hemorrhage

Quantitative Susceptibility Mapping (QSM) MRI allows accurate assessment of iron content in cerebral cavernous malformations (CCM), and a threshold increase by 6% in QSM has been shown to reflect new symptomatic hemorrhage (SH) in previously stable lesions.

Plasma Biomarkers of Inflammation and Angiogenesis Predict Cerebral Cavernous Malformation Symptomatic Hemorrhage or Lesional Growth

Rationale: The clinical course of cerebral cavernous malformations is highly unpredictable, with few cross-sectional studies correlating proinflammatory genotypes and plasma biomarkers with prior disease severity. Objective: We hypothesize that a panel of 24 candidate plasma biomarkers, with a reported role in the physiopathology of cerebral cavernous malformations, may predict subsequent clinically relevant disease activity. Methods and Results: Plasma biomarkers were assessed in nonfasting peripheral venous blood collected from consecutive cerebral cavernous malformation subjects followed for 1 year after initial sample collection. A first cohort (N=49) was used to define the best model of biomarker level combinations to predict a subsequent symptomatic lesional hemorrhagic expansion within a year after the blood sample. We generated the receiver operating characteristic curves and area under the curve for each biomarker individually and each weighted linear combination of relevant biomarkers. The best model to predict lesional activity was selected as that minimizing the Akaike information criterion. In this cohort, 11 subjects experienced symptomatic lesional hemorrhagic expansion (5 bleeds and 10 lesional growths) within a year after the blood draw. Subjects had lower soluble CD14 (cluster of differentiation 14; P=0.05), IL (interleukin)-6 (P=0.04), and VEGF (vascular endothelial growth factor; P=0.0003) levels along with higher plasma levels of IL-1&bgr; (P=0.008) and soluble ROBO4 (roundabout guidance receptor 4; P=0.03). Among the 31 weighted linear combinations of these 5 biomarkers, the best model (with the lowest Akaike information criterion value, 25.3) was the weighted linear combination including soluble CD14, IL-1&bgr;, VEGF, and soluble ROBO4, predicting a symptomatic hemorrhagic expansion with a sensitivity of 86% and specificity of 88% (area under the curve, 0.90; P<0.0001). We then validated our best model in the second sequential independent cohort (N=28). Conclusions: This is the first study reporting a predictive association between plasma biomarkers and subsequent cerebral cavernous malformation disease clinical activity. This may be applied in clinical prognostication and stratification of cases in clinical trials.