Cerebral amyloid angiopathy-associated intracerebral hemorrhage: pathology and management

An interpretable artificial intelligence model based on CT for prognosis of intracerebral hemorrhage: a multicenter study

OBJECTIVES

To develop and validate a novel interpretable artificial intelligence (AI) model that integrates radiomic features, deep learning features, and imaging features at multiple semantic levels to predict the prognosis of intracerebral hemorrhage (ICH) patients at 6 months post-onset.

MATERIALS AND METHODS

Retrospectively enrolled 222 patients with ICH for Non-contrast Computed Tomography (NCCT) images and clinical data, who were divided into a training cohort (n = 186, medical center 1) and an external testing cohort (n = 36, medical center 2). Following image preprocessing, the entire hematoma region was segmented by two radiologists as the volume of interest (VOI). Pyradiomics algorithm library was utilized to extract 1762 radiomics features, while a deep convolutional neural network (EfficientnetV2-L) was employed to extract 1000 deep learning features. Additionally, radiologists evaluated imaging features. Based on the three different modalities of features mentioned above, the Random Forest (RF) model was trained, resulting in three models (Radiomics Model, Radiomics-Clinical Model, and DL-Radiomics-Clinical Model). The performance and clinical utility of the models were assessed using the Area Under the Receiver Operating Characteristic Curve (AUC), calibration curve, and Decision Curve Analysis (DCA), with AUC compared using the DeLong test. Furthermore, this study employs three methods, Shapley Additive Explanations (SHAP), Grad-CAM, and Guided Grad-CAM, to conduct a multidimensional interpretability analysis of model decisions.

RESULTS

The Radiomics-Clinical Model and DL-Radiomics-Clinical Model exhibited relatively good predictive performance, with an AUC of 0.86 [95% Confidence Intervals (CI): 0.71, 0.95; P < 0.01] and 0.89 (95% CI: 0.74, 0.97; P < 0.01), respectively, in the external testing cohort.

CONCLUSION

The multimodal explainable AI model proposed in this study can accurately predict the prognosis of ICH. Interpretability methods such as SHAP, Grad-CAM, and Guided Grad-Cam partially address the interpretability limitations of AI models. Integrating multimodal imaging features can effectively improve the performance of the model.

CLINICAL RELEVANCE STATEMENT

Predicting the prognosis of patients with ICH is a key objective in emergency care. Accurate and efficient prognostic tools can effectively prevent, manage, and monitor adverse events in ICH patients, maximizing treatment outcomes.

Management of cerebral amyloid angiopathy and atrial fibrillation: We are still far from precision medicine

The use of anticoagulation therapy could prove to be controversial when trying to balance ischemic stroke and intracranial bleeding risks in patients with concurrent cerebral amyloid angiopathy (CAA) and atrial fibrillation (AF). In fact, CAA is an age-related cerebral vasculopathy that predisposes patients to intracerebral hemorrhage. Nevertheless, many AF patients require oral systemic dose-adjusted warfarin, direct oral anticoagulants (such as factor Xa inhibitors) or direct thrombin inhibitors to control often associated with cardioembolic stroke risk. The prevalence of both CAA and AF is expected to rise, due to the aging of the population. This clinical dilemma is becoming increasingly common. In patients with coexisting AF and CAA, the risks/benefits profile of anticoagulant therapy must be assessed for each patient individually due to the lack of a clear-cut consensus with regard to its risks in scientific literature. This review aims to provide an overview of the management of patients with concomitant AF and CAA and proposes the implementation of a risk-based decision-making algorithm.

Could Alcohol-Related Cognitive Decline Be the Result of Iron-Induced Neuroinflammation?

Excessive and prolonged alcohol use can have long-term severe neurological consequences. The mechanisms involved may be complicated; however, new evidence seems to indicate the involvement of iron accumulation and neuroinflammation. Prolonged alcohol consumption has been linked to the accumulation of iron in specific regions of the brain. Evidence suggests that excess iron in the brain can trigger microglia activation in response. This activation leads to the release of pro-inflammatory cytokines and reactive oxygen species, which can cause damage to neurons and surrounding brain tissue. Additionally, iron-induced oxidative stress and inflammation can disrupt the blood-brain barrier, allowing immune cells from the periphery to infiltrate the brain. This infiltration can lead to further neuroinflammatory responses. Inflammation in the brain subsequently disrupts neuronal networks, impairs synaptic plasticity, and accelerates neuronal cell death. Consequently, cognitive functions such as memory, attention, and decision-making are compromised. Additionally, chronic neuroinflammation can hasten the development and progression of neurodegenerative diseases, further exacerbating cognitive impairment. Therefore, alcohol could act as a trigger for iron-induced neuroinflammation and cognitive decline. Overall, the mechanisms at play here seem to strongly link alcohol with cognitive decline, with neuroinflammation resulting from alcohol-induced iron accumulation playing a pivotal role.

Sex-specific mechanisms of cerebral microvascular BK Ca dysfunction in a mouse model of Alzheimer's disease

BACKGROUND

Cerebral microvascular dysfunction and nitro-oxidative stress are present in patients with Alzheimer's disease (AD) and may contribute to disease progression and severity. Large conductance Ca 2+ -activated K + channels (BK Ca ) play an essential role in vasodilatory responses and maintenance of myogenic tone in resistance arteries. BK Ca impairment can lead to microvascular dysfunction and hemodynamic deficits in the brain. We hypothesized that reduced BK Ca function in cerebral arteries mediates microvascular and neurovascular responses in the 5x-FAD model of AD.

METHODS

BK Ca activity in the cerebral microcirculation was assessed by patch clamp electrophysiology and pressure myography, in situ Ca 2+ sparks by spinning disk confocal microscopy, hemodynamics by laser speckle contrast imaging. Molecular and biochemical analyses were conducted by affinity-purification assays, qPCR, Western blots and immunofluorescence.

RESULTS

We observed that pial arteries from 5-6 months-old male and female 5x-FAD mice exhibited a hyper-contractile phenotype than wild-type (WT) littermates, which was linked to lower vascular BK Ca activity and reduced open probability. In males, BK Ca dysfunction is likely a consequence of an observed lower expression of the pore-forming subunit BKα and blunted frequency of Ca 2+ sparks, which are required for BK Ca activity. However, in females, impaired BK Ca function is, in part, a consequence of reversible nitro-oxidative changes in the BK α subunit, which reduces its open probability and regulation of vascular tone. We further show that BK Ca function is involved in neurovascular coupling in mice, and its dysfunction is linked to neurovascular dysfunction in the model.

CONCLUSION

These data highlight the central role played by BK Ca in cerebral microvascular and neurovascular regulation, as well as sex-dependent mechanisms underlying its dysfunction in a mouse model of AD.

Subcortical hemorrhage caused by cerebral amyloid angiopathy compared with hypertensive hemorrhage

OBJECTIVES

Most published reports on lobular hemorrhage in cerebral amyloid angiopathy (CAA) include patients diagnosed only by imaging studies. This study analyzed patients with subcortical hemorrhage histologically diagnosed as CAA or non-CAA (hypertensive).

METHODS

This is a retrospective study analyzing data from 100 craniotomy cases. Tissue of hematoma cavity wall was collected for histological investigation in hematoma removal by surgery in patients with subcortical hemorrhage. Statistical analyses of blood pressure, hematoma location and volume, outcome, and mortality was performed in CAA and non-CAA groups.

RESULTS

There were 47 CAA and 53 non-CAA cases, and average age was significantly older in the CAA group (p < 0.01). Blood pressure was significantly lower (p < 0.01) but hematoma volume was significantly greater (p < 0.05) in the CAA group. Rebleeding occurred in two CAA cases and one non-CAA case, but no re-operations were required. Average score of modified Rankin Scale, which is used to measure the degree of disability in patients who have had a stroke, at three months after surgery was not significantly different between the two groups (CAA: 3.94 ± 1.28, non-CAA: 3.58 ± 1.50). There were seven deaths in the CAA and six in the non-CAA group, and intraventricular hemorrhage highly complicated in the death cases in both groups. In the CAA group, average age of the fatal cases was significantly older than that of the surviving cases (p < 0.05) and six cases demonstrated dementia before onset of hemorrhage.

CONCLUSIONS

Surgical removal of a subcortical hemorrhage caused by CAA is not contraindicated. However, age > 80 years, complication with intraventricular hemorrhage, hematoma volume ≥ 50 ml, and dementia before onset of hemorrhage contribute to high mortality, and craniotomy should be carefully considered for such patients. A limitation of this study is that comparison between CAA and non-CAA groups was performed in the patients with only surgically indicated ICH, and does not evaluate entire ICH cases with CAA. However, this study appropriately compared pathologically diagnosed CAA and non-CAA in patients with moderate to severe lobular ICH with surgical indications.

Incidence and risk factors associated with seizures in cerebral amyloid angiopathy

BACKGROUND AND PURPOSE

Cerebral amyloid angiopathy (CAA) is a common cause of intracranial hemorrhage (ICH), which is a risk factor for seizures. The incidence and risk factors of seizures associated with a heterogeneous cohort of CAA patients have not been studied.

METHODS

We conducted a retrospective study of patients with CAA treated at Mayo Clinic Florida between 1 January 2015 and 1 January 2021. CAA was defined using the modified Boston criteria version 2.0. We analyzed electrophysiological and clinical features, and comorbidities including lobar ICH, nontraumatic cortical/convexity subarachnoid hemorrhage (cSAH), superficial siderosis, and inflammation (CAA with inflammation [CAA-ri]). Cognition and mortality were secondary outcomes. Univariate and multivariate analyses were performed to determine risk of seizures relative to clinical presentation.

RESULTS

Two hundred eighty-four patients with CAA were identified, with median follow-up of 35.7 months (interquartile range = 13.5-61.3 months). Fifty-six patients (19.7%) had seizures; in 21 (37.5%) patients, seizures were the index feature leading to CAA diagnosis. Seizures were more frequent in females (p = 0.032) and patients with lobar ICH (p = 0.002), cSAH (p = 0.030), superficial siderosis (p < 0.001), and CAA-ri (p = 0.005), and less common in patients with microhemorrhage (p = 0.006). After controlling for age and sex, lobar ICH (odds ratio [OR] = 2.1, 95% confidence interval [CI] = 1.1-4.2), CAA-ri (OR = 3.8, 95% CI = 1.4-10.3), and superficial siderosis (OR = 3.7, 95% CI = 1.9-7.0) were independently associated with higher odds of incident seizures.

CONCLUSIONS

Seizures are common in patients with CAA and are independently associated with lobar ICH, CAA-ri, and superficial siderosis. Our results may be applied to optimize clinical monitoring and management for patients with CAA.

Risk factors for recurrent cerebral amyloid angiopathy-related intracerebral hemorrhage

Background

Cerebral amyloid angiopathy (CAA) is the most common cause of lobar intracerebral hemorrhage (ICH) in the elderly, and its multifocal and recurrent nature leads to high rates of disability and mortality. Therefore, this study aimed to summarize the evidence regarding the recurrence rate and risk factors for CAA-related ICH (CAA-ICH).

Methods

We performed a systematic literature search of all English studies published in PubMed, Embase, Web of Science, Cochrane Library, Scopus, and CINAHL from inception to June 10, 2023. Studies reporting CAA-ICH recurrence rates and risk factors for CAA-ICH recurrence were included. We calculated pooled odds ratios (ORs) with their corresponding 95% confidence intervals (CIs) using a random/fixed-effects model based on the I2 assessment of heterogeneity between studies. Publication bias was assessed using Egger's test.

Results

Thirty studies were included in the final analysis. Meta-analysis showed that the recurrence rate of CAA-ICH was 23% (95% CI: 18-28%, I2 = 96.7%). The risk factors significantly associated with CAA-ICH recurrence were: previous ICH (OR = 2.03; 95% CI: 1.50-2.75; I2 = 36.8%; N = 8), baseline ICH volume (OR = 1.01; 95% CI: 1-1.02; I2 = 0%; N = 4), subarachnoid hemorrhage (cSAH) (OR = 3.05; 95% CI: 1.86-4.99; I2 = 0%; N = 3), the presence of cortical superficial siderosis (cSS) (OR = 2.04; 95% CI: 1.46-2.83; I2 = 0%; N = 5), disseminated cSS (OR = 3.21; 95% CI: 2.25-4.58; I2 = 16.0%; N = 6), and centrum semiovale-perivascular spaces (CSO-PVS) severity (OR = 1.67; 95% CI: 1.14-2.45; I2 = 0%; N = 4).

Conclusion

CAA-ICH has a high recurrence rate. cSAH, cSS (especially if disseminated), and CSO-PVS were significant markers for recurrent CAA-ICH. The onset of ICH in patients with CAA is usually repeated several times, and recurrence is partly related to the index ICH volume. Identifying clinical and neuroimaging predictors of CAA-ICH recurrence is of great significance for evaluating outcomes and improving the prognosis of patients with CAA-ICH.

Systematic review registration

https://www.crd.york.ac.uk/PROSPERO/display_record.php?RecordID=400240, identifier [CRD42023400240].

Primary Intracranial Hemorrhage: Characteristics, Distribution, Risk Factors, and Outcomes-A Comparative Study between Jewish and Arab Ethnic Groups in Northern Israel

Background and purpose: This study aimed to investigate the differences in intracerebral hemorrhage (ICH) between Jews and Arabs residing in northern Israel, focusing on risk factors, hemorrhage volume, and functional outcome. Methods: A retrospective analysis was conducted utilizing a population-based registry to investigate intracerebral hemorrhage (ICH) characteristics, risk factors, and outcomes. The registry consisted of inpatients diagnosed with hemorrhagic stroke. Due to the wide variation in data on ICH characteristics and the limited availability of population-based data on predictors of ICH survival and functional outcomes, we collected retrospective data on all adult patients admitted to the Galilee Medical Center with a diagnosis of ICH. Data were obtained from the registry covering the period from 2013 to 2019. Ethnic differences and risk factors associated with intracranial hemorrhage (ICH) were examined within a diverse population of 241 patients, comprising 52.70% Jews (n = 127) and 47.30% Arabs (n = 114). Results: The results of this study revealed significant differences in age, obesity rates, and intracerebral hemorrhage (ICH) location between the two ethnic groups. Hypertension emerged as the most prevalent condition among ICH patients in both ethnic groups (76.70%), followed primarily by anticoagulant use (63.60%), dyslipidemia (60.70%), diabetes (44.60%), obesity (30.60%), smoking (24.60%), and a history of cardiovascular disease (21.80%). Furthermore, 20.90% of the patients had a history of previous cerebrovascular accidents (CVA). Arab patients with ICH were generally younger (62.90 ± 16.00 years) and exhibited higher rates of obesity (38.70%) compared to Jewish patients with ICH (70.17 ± 15.24 years, 23% obesity; p = 0.001, p = 0.013, respectively). Hemorrhage volume was identified as a crucial determinant of patient outcomes, with larger volumes associated with poorer Modified Rankin Scale (mRS) scores at discharge and higher mortality rates. Interestingly, patients without hypertension had higher hemorrhage volumes compared to those with hypertension. The extent of hemorrhage into the ventricles did not significantly correlate with mRS at discharge in our dataset. Conclusions: This study highlights significant differences in the characteristics and outcomes of intracranial hemorrhage (ICH) between Jews and Arabs in northern Israel. The findings reveal variations in age, obesity rates, and ICH location between the two groups. While hypertension was the most prevalent risk factor for both populations, other risk factors differed. Notably, hemorrhage volume emerged as a crucial prognostic factor, aligning with previously published data. These findings underscore the necessity for tailored approaches that consider ethnic-specific factors in the risk assessment, prevention, and management of ICH. Further research is warranted to elucidate the underlying mechanisms and develop interventions aimed at improving outcomes and enhancing healthcare practices in ICH management.

Management of oral anticoagulant therapy after intracranial hemorrhage in patients with atrial fibrillation

Intracranial hemorrhage (ICH) is considered a potentially severe complication of oral anticoagulants (OACs) and antiplatelet therapy (APT). Patients with atrial fibrillation (AF) who survived ICH present both an increased ischemic and bleeding risk. Due to its lethality, initiating or reinitiating OACs in ICH survivors with AF is challenging. Since ICH recurrence may be life-threatening, patients who experience an ICH are often not treated with OACs, and thus remain at a higher risk of thromboembolic events. It is worthy of mention that subjects with a recent ICH and AF have been scarcely enrolled in randomized controlled trials (RCTs) on ischemic stroke risk management in AF. Nevertheless, in observational studies, stroke incidence and mortality of patients with AF who survived ICH had been shown to be significantly reduced among those treated with OACs. However, the risk of hemorrhagic events, including recurrent ICH, was not necessarily increased, especially in patients with post-traumatic ICH. The optimal timing of anticoagulation initiation or restarting after an ICH in AF patients is also largely debated. Finally, the left atrial appendage occlusion option should be evaluated in AF patients with a very high risk of recurrent ICH. Overall, an interdisciplinary unit consisting of cardiologists, neurologists, neuroradiologists, neurosurgeons, patients, and their families should be involved in management decisions. According to available evidence, this review outlines the most appropriate anticoagulation strategies after an ICH that should be adopted to treat this neglected subset of patients.

Mesenchymal stem cell-derived extracellular vesicles/exosome: A promising therapeutic strategy for intracerebral hemorrhage

Intracerebral hemorrhage (ICH) is the second largest type of stroke with high mortality and morbidity. The vast majority of survivors suffer from serious neurological defects. Despite the well-established etiology and diagnose, there is still some controversy over the ideal treatment strategy. MSC-based therapy has become an attractive and promising strategy for the treatment of ICH through immune regulation and tissue regeneration. However, accumulating studies have revealed that MSC-based therapeutic effects are mainly attributed to the paracrine properties of MSC, especially small extracellular vesicles/exosome (EVs/exo) which are considered to be the key mediators of the protective efficacy from MSCs. Moreover, some papers reported that MSC-EVs/exo have better therapeutic effects than MSCs. Therefore, EVs/exo has become a new choice for the treatment of ICH stroke in recent years. In this review, we mainly concentrate on the current research progress on the use of MSC-EVs/exo in the treatment of ICH and the existing challenges in their transplation from lab to clinical practice.

Neuroimaging biomarkers of small vessel disease in cerebral amyloid angiopathy-related intracerebral hemorrhage

AIMS

The significance of the correlation of computed tomography (CT)-based cerebral small vessel disease (SVD) markers with the clinical outcomes in patients with cerebral amyloid angiopathy (CAA)-related intracerebral hemorrhage (ICH) remains uncertain. Thus, this study aimed to explore the relationship between SVD markers and short-term outcomes of CAA-ICH.

METHODS

A total of 183 patients with CAA-ICH admitted to the Xuanwu Hospital, and Beijing Fengtai You'anmen Hospital, from 2014 to 2021 were included. The multivariate logistic regression analysis was performed to identify the correlation between SVD markers based on CT and clinical outcomes at 7-day and 90-day.

RESULTS

Of the 183 included patients, 66 (36%) were identified with severe SVD burden. The multivariate analysis showed that the total SVD burden, white matter lesion (WML) grade, and brain atrophy indicator were independent risk factors for unfavorable outcomes at 90-day. The brain atrophy indicator was independently associated with mortality at 90-day. Severe cortical atrophy was significantly associated with early neurological deterioration.

CONCLUSIONS

The neuroimaging profiles of SVD based on CT in patients with CAA-ICH might predict the short-term outcome more effectively. Further studies are required to validate these findings and identify modifiable factors for preventing CAA-ICH development.

Evaluation of Copper Chelation Therapy in a Transgenic Rat Model of Cerebral Amyloid Angiopathy

Cerebral amyloid angiopathy (CAA) is characterized by the accumulation of the amyloid β (Aβ) protein in blood vessels and leads to hemorrhages, strokes, and dementia in elderly individuals. Recent reports have shown elevated copper levels colocalized with vascular amyloid in human CAA and Alzheimer's disease patients, which have been suggested to contribute to cytotoxicity through the formation of reactive oxygen species. Here, we treated a transgenic rat model of CAA (rTg-DI) with the copper-specific chelator, tetrathiomolybdate (TTM), via intraperitoneal (IP) administration for 6 months to determine if it could lower copper content in vascular amyloid deposits and modify CAA pathology. Results showed that TTM treatment led to elevated Aβ load in the hippocampus of the rTg-DI rats and increased microbleeds in the wild type (WT) animals. X-ray fluorescence microscopy was performed to image the distribution of copper and revealed a surprising increase in copper colocalized with Aβ aggregates in TTM-treated rTg-DI rats. Unexpectedly, we also found an increase in the copper content in unaffected vessels of both rTg-DI and WT animals. These results show that IP administration of TTM was ineffective in removing copper from vascular Aβ aggregates in vivo and increased the development of disease pathology in CAA.

Applicability of the Edinburgh CT Criteria for Lobar Intracerebral Hemorrhage Associated with Cerebral Amyloid Angiopathy

OBJECTIVE

Based on histopathology, Edinburgh diagnostic criteria were proposed to consider a nontraumatic intracerebral lobar hemorrhage (ICH) as related to cerebral amyloid angiopathy (CAA) using the initial computed tomography (CT) scan and the APOE genetic status. We aimed to externally validate the Edinburgh prediction model, excluding the APOE genotyping and based on the modified Boston criteria on the MRI for CAA diagnosis METHODS: We included patients admitted for spontaneous lobar ICH in the emergency department between 2016 and 2019 who underwent noncontrast CT scan and MRI. According to the MRI, patients were classified into the CAA group or into the non-CAA group in the case of other causes of ICH. Two neuroradiologists, blinded to the final retained diagnosis, rated each radiological feature on initial CT scan described in the Edinburgh study on initial CT scan RESULTS: A total of 102 patients were included, of whom 36 were classified in the CAA group, 46 in the non-CAA causes group and 20 of undetermined cause (excluded from the primary analysis). The Edinburgh prediction model, including finger-like projections and subarachnoid extension showed an area under receiver operating characteristic curves (AUC) of 0.760 (95% confidence interval, CI: 0.660-0.859) for the diagnosis of CAA. The AUC reached 0.808 (95% CI: 0.714-0.901) in a new prediction model integrating a third radiologic variable: the ICH cortical involvement.

CONCLUSION

Using the Boston MRI criteria as a final assessment, we provided a new external confirmation of the radiological Edinburgh CT criteria, which are directly applicable in acute settings of spontaneous lobar ICH and further proposed an original 3‑set model considering finger-like projections, subarachnoid extension, and cortical involvement that may achieve a high discrimination performance.

The prognostic value of the Charlson comorbidity index in aged patients with intracerebral hemorrhage

BACKGROUND

Comorbidities are common in aged intracerebral hemorrhage patients. The purpose of this study was to assess whether the Charlson Comorbidity Index (CCI) was associated with in-hospital death and short-term functional outcome in elderly patients (age ≥ 70) with intracerebral hemorrhage (ICH).

METHODS

This was a retrospective cohort of aged ICH patients (≥70 years old) admitted within 24 hours of ICH onset. The CCI was derived using hospital discharge ICD-9 CM codes and patient history obtained from standardized case report forms. Multivariable logistic regression was used to determine the independent effect of the CCI score on clinical outcomes.

RESULTS

In this cohort of 248 aged ICH patients, comorbid conditions were common, with CCI scores ranging from 2 to 12. Logistic regression showed that the CCI score was independently predictive of 1-month functional outcome (OR = 1.642, P < 0.001) and in-hospital death (OR = 1.480, P = 0.003). Neither ICH volume nor the presence of IVH was an independent predictive factor for 1-month functional outcome or in-hospital mortality (P < 0.05).

CONCLUSION

Comorbid medical conditions as assessed by the CCI independently influence short-term outcomes in aged ICH patients. The characteristics of the hematoma itself, such as ICH volume and the presence of IVH, seem to have a reduced effect on it.

When less is more: Non-contrast head CT alone to work-up hypertensive intracerebral hemorrhage

Hypertension is a common cause of intracerebral hemorrhage (ICH). The work up typically involves neuroimaging of the brain and blood vessels to determine etiology. However, extensive testing may be unnecessary for presumed hypertensive hemorrhages, and instead prolong hospital stay and increase costs. This study evaluates the predictive utility of hemorrhage location on the non-contrast head CT in determining hypertensive ICH. Patients presenting with non-traumatic ICH between March 2014 and June 2019 were prospectively enrolled. Hemorrhage etiology was determined based on previously defined criteria. Chi square and Student's t tests were used to determine the association between patient demographics, ICH severity, neuroimaging characteristics, and medical variables, with hypertensive etiology. Multivariable regression models and an ROC analysis determined utility of CT to accurately diagnose hypertensive ICH. Data on 380 patients with ICH were collected; 42% were determined to be hypertensive. Along with deep location on CT, black race, history of hypertension, renal disease, left ventricular hypertrophy, and higher admission blood pressure were significantly associated with hypertensive etiology, while atrial fibrillation and anticoagulation were associated with non-hypertensive etiologies. Deep location alone resulted in an area under the curve of 0.726. When history of hypertension was added, this improved to 0.771. Additional variables did not further improve the model's predictability. Hypertensive ICH is associated with several predictive factors. Using deep location and history of hypertension alone correctly identifies the majority of hypertensive ICH without additional work-up. This model may result in more efficient diagnostic testing without sacrificing patient care.

Intracerebral Hemorrhage: The Effects of Aging on Brain Injury

Intracerebral hemorrhage (ICH) is a devastating subtype of stroke with high rates of mortality and morbidity. ICH patients often suffer devastating and debilitating neurological impairments, from which the majority of victims are unable to fully recover to functional independence. Unfortunately, there is no established medical therapy for ICH, which is partly attributed to the lack of understanding of the complex pathology of the disorder. Despite advanced age being a major risk factor of ICH, most preclinical studies on ICH employed young animal subjects. Due to this discrepancy, the molecular level changes in the aging brain after ICH are largely unknown, limiting the translation of preclinical studies into potential human treatments. The purpose of this review is to highlight the effects of advanced age on ICH- induced brain injury and recovery and to draw attention to current knowledge gaps, which warrant further investigation.

Impact of Non-pharmacological Chronic Hypertension on a Transgenic Rat Model of Cerebral Amyloid Angiopathy

Cerebral amyloid angiopathy (CAA), a common comorbidity of Alzheimer’s disease (AD), is a cerebral small vessel disease (CSVD) characterized by deposition of fibrillar amyloid β (Aβ) in blood vessels of the brain and promotes neuroinflammation and vascular cognitive impairment and dementia (VCID). Hypertension, a prominent non-amyloidal CSVD, has been found to increase risk of dementia, but clinical data regarding its effects in CAA patients is controversial. To understand the effects of hypertension on CAA, we bred rTg-DI transgenic rats, a model of CAA, with spontaneously hypertensive, stroke prone (SHR-SP) rats producing bigenic rTg-DI/SHR-SP and non-transgenic SHR-SP littermates. At 7 months (M) of age, cohorts of both rTg-DI/SHR-SP and SHR-SP littermates exhibit elevated systolic blood pressures. However, transgene human amyloid β-protein (Aβ) precursor and Aβ peptide levels, as well as behavioral testing showed no changes between bigenic rTg-DI/SHR-SP and rTg-DI rats. Subsequent cohorts of rats were aged further to 10 M where bigenic rTg-DI/SHR-SP and SHR-SP littermates exhibit elevated systolic and diastolic blood pressures. Vascular amyloid load in hippocampus and thalamus was significantly decreased, whereas pial surface vessel amyloid increased, in bigenic rTg-DI/SHR-SP rats compared to rTg-DI rats suggesting a redistribution of vascular amyloid in bigenic animals. There was activation of both astrocytes and microglia in rTg-DI rats and bigenic rTg-DI/SHR-SP rats not observed in SHR-SP rats indicating that glial activation was likely in response to the presence of vascular amyloid. Thalamic microbleeds were present in both rTg-DI rats and bigenic rTg-DI/SHR-SP rats. Although the number of thalamic small vessel occlusions were not different between rTg-DI and bigenic rTg-DI/SHR-SP rats, a significant difference in occlusion size and distribution in the thalamus was found. Proteomic analysis of cortical tissue indicated that bigenic rTg-DI/SHR-SP rats largely adopt features of the rTg-DI rats with enhancement of certain changes. Our findings indicate that at 10 M of age non-pharmacological hypertension in rTg-DI rats causes a redistribution of vascular amyloid and significantly alters the size and distribution of thalamic occluded vessels. In addition, our findings indicate that bigenic rTg-DI/SHR-SP rats provide a non-pharmacological model to further study hypertension and CAA as co-morbidities for CSVD and VCID.

Minimally Invasive Surgery for Intracerebral and Intraventricular Hemorrhage

Spontaneous intracerebral hemorrhage (ICH), especially related to intraventricular hemorrhage (IVH), is the most devastating type of stroke and is associated with high mortality and morbidity. Optimal management of ICH remains one of the most controversial areas of neurosurgery and no effective treatment exists for ICH. Studies comparing conventional surgical interventions with optimal medical management failed to show significant benefit. Recent exploration of minimally invasive surgery for ICH and IVH including catheter- and mechanical-based approaches has shown great promise. Early phase clinical trials have confirmed the safety and preliminary treatment effect of minimally invasive surgery for ICH and IVH. Pending efficacy data from phase III trials dealing with diverse minimally invasive techniques are likely to shape the treatment of ICH.

Clonal Hematopoiesis Is Associated With Higher Risk of Stroke

BACKGROUND AND PURPOSE

Clonal hematopoiesis of indeterminate potential (CHIP) is a novel age-related risk factor for cardiovascular disease-related morbidity and mortality. The association of CHIP with risk of incident ischemic stroke was reported previously in an exploratory analysis including a small number of incident stroke cases without replication and lack of stroke subphenotyping. The purpose of this study was to discover whether CHIP is a risk factor for ischemic or hemorrhagic stroke.

METHODS

We utilized plasma genome sequence data of blood DNA to identify CHIP in 78 752 individuals from 8 prospective cohorts and biobanks. We then assessed the association of CHIP and commonly mutated individual CHIP driver genes (DNMT3A, TET2, and ASXL1) with any stroke, ischemic stroke, and hemorrhagic stroke.

RESULTS

CHIP was associated with an increased risk of total stroke (hazard ratio, 1.14 [95% CI, 1.03-1.27]; P=0.01) after adjustment for age, sex, and race. We observed associations with CHIP with risk of hemorrhagic stroke (hazard ratio, 1.24 [95% CI, 1.01-1.51]; P=0.04) and with small vessel ischemic stroke subtypes. In gene-specific association results, TET2 showed the strongest association with total stroke and ischemic stroke, whereas DMNT3A and TET2 were each associated with increased risk of hemorrhagic stroke.

CONCLUSIONS

CHIP is associated with an increased risk of stroke, particularly with hemorrhagic and small vessel ischemic stroke. Future studies clarifying the relationship between CHIP and subtypes of stroke are needed.

Serum Amyloid A Is Present in Human Saccular Intracranial Aneurysm Walls and Associates With Aneurysm Rupture

Saccular intracranial aneurysm (sIA) rupture leads to a disabling subarachnoid hemorrhage. Chronic inflammation and lipid accumulation in the sIA wall contribute to wall degenerative remodeling that precedes its rupture. A better understanding of the pathobiological process is essential for improved future treatment of patients carrying sIAs. Serum amyloid A (SAA) is an acute-phase protein produced in response to acute and chronic inflammation and tissue damage. Here, we studied the presence and the potential role of SAA in 36 intraoperatively resected sIAs (16 unruptured and 20 ruptured), that had previously been studied by histology and immunohistochemistry. SAA was present in all sIAs, but the extent of immunopositivity varied greatly. SAA immunopositivity correlated with wall degeneration (p = 0.028) and rupture (p = 0.004), with numbers of CD163-positive and CD68-positive macrophages and CD3-positive T lymphocytes (all p < 0.001), and with the expression of myeloperoxidase, matrix metalloproteinase-9, prostaglandin E-2 receptor, and cyclo-oxygenase 2 in the sIA wall. Moreover, SAA positivity correlated with the accumulation of apolipoproteins A-1 and B-100. In conclusion, SAA occurs in the sIA wall and, as an inflammation-related factor, may contribute to the development of a rupture-prone sIA.

Retinal Vasculopathy in Alzheimer's Disease

The retina has been increasingly investigated as a site of Alzheimer’s disease (AD) manifestation for over a decade. Early reports documented degeneration of retinal ganglion cells and their axonal projections. Our group provided the first evidence of the key pathological hallmarks of AD, amyloid β-protein (Aβ) plaques including vascular Aβ deposits, in the retina of AD and mild cognitively impaired (MCI) patients. Subsequent studies validated these findings and further identified electroretinography and vision deficits, retinal (p)tau and inflammation, intracellular Aβ accumulation, and retinal ganglion cell-subtype degeneration surrounding Aβ plaques in these patients. Our data suggest that the brain and retina follow a similar trajectory during AD progression, probably due to their common embryonic origin and anatomical proximity. However, the retina is the only CNS organ feasible for direct, repeated, and non-invasive ophthalmic examination with ultra-high spatial resolution and sensitivity. Neurovascular unit integrity is key to maintaining normal CNS function and cerebral vascular abnormalities are increasingly recognized as early and pivotal factors driving cognitive impairment in AD. Likewise, retinal vascular abnormalities such as changes in vessel density and fractal dimensions, blood flow, foveal avascular zone, curvature tortuosity, and arteriole-to-venule ratio were described in AD patients including early-stage cases. A rapidly growing number of reports have suggested that cerebral and retinal vasculopathy are tightly associated with cognitive deficits in AD patients and animal models. Importantly, we recently identified early and progressive deficiency in retinal vascular platelet-derived growth factor receptor-β (PDGFRβ) expression and pericyte loss that were associated with retinal vascular amyloidosis and cerebral amyloid angiopathy in MCI and AD patients. Other studies utilizing optical coherence tomography (OCT), retinal amyloid-fluorescence imaging and retinal hyperspectral imaging have made significant progress in visualizing and quantifying AD pathology through the retina. With new advances in OCT angiography, OCT leakage, scanning laser microscopy, fluorescein angiography and adaptive optics imaging, future studies focusing on retinal vascular AD pathologies could transform non-invasive pre-clinical AD diagnosis and monitoring.

Index event of cerebral amyloid angiopathy (CAA) determines long-term prognosis and recurrent events (retrospective analysis and clinical follow-up)

Background

The modified Boston criteria (mBC) define the probability for the diagnosis of cerebral amyloid angiopathy (CAA). Its initial clinical presentation differs from asymptomatic cerebral microbleedings (cMBs), acute ischemic stroke (AIS), cortical hemosiderosis (cSS), to lobar ICH (lICH).

Methods

Retrospective analyses and clinical follow-ups of individuals with at least mBC “possible” CAA from 2005 to 2018.

Results

149 patients were classified in subgroups due to the index event: lICH (n = 91), AIS (n = 32), > 3 cMBs only (n = 16) and cSS (n = 10). Patients in the lICH subgroup had a significantly higher percentage of single new lICHs compared to other groups, whereas patients in the AIS-group had a significantly higher percentage of multiple new AIS. cMBs as index event predisposed for AIS during follow up (p < 0.0016). Patients of the cMBs- or cSS-group showed significantly more TFNEs (transient focal-neurological episodes) and lower numbers of asymptomatic patients (for epilepsy and TFNEs) at the index event than patients with lICH or AIS (p < 0.0013). At long-term follow-up, the cMBs- and cSS-group were characterized by more TFNEs and fewer asymptomatic patients.

Conclusions

A new classification system of CAA should add subgroups according to the initial clinical presentation to the mBCs allowing individual prognosis, acute treatment and secondary prophylaxis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s42466-021-00152-x.

Cerebral Microbleeds in Fragile X-Associated Tremor/Ataxia Syndrome

BACKGROUND

Fragile X-associated tremor/ataxia syndrome is a neurodegenerative disease of late onset developed by carriers of the premutation in the fragile x mental retardation 1 (FMR1) gene. Pathological features of neurodegeneration in fragile X-associated tremor/ataxia syndrome include toxic levels of FMR1 mRNA, ubiquitin-positive intranuclear inclusions, white matter disease, iron accumulation, and a proinflammatory state.

OBJECTIVE

The objective of this study was to analyze the presence of cerebral microbleeds in the brains of patients with fragile X-associated tremor/ataxia syndrome and investigate plausible causes for cerebral microbleeds in fragile X-associated tremor/ataxia syndrome.

METHODS

We collected cerebral and cerebellar tissue from 15 fragile X-associated tremor/ataxia syndrome cases and 15 control cases carrying FMR1 normal alleles. We performed hematoxylin and eosin, Perls and Congo red stains, ubiquitin, and amyloid β protein immunostaining. We quantified the number of cerebral microbleeds, amount of iron, presence of amyloid β within the capillaries, and number of endothelial cells containing intranuclear inclusions. We evaluated the relationships between pathological findings using correlation analysis.

RESULTS

We found intranuclear inclusions in the endothelial cells of capillaries and an increased number of cerebral microbleeds in the brains of those with fragile X-associated tremor/ataxia syndrome, both of which are indicators of cerebrovascular dysfunction. We also found a suggestive association between the amount of capillaries that contain amyloid β in the cerebral cortex and the rate of disease progression.

CONCLUSION

We propose microangiopathy as a pathologic feature of fragile X-associated tremor/ataxia syndrome. © 2021 International Parkinson and Movement Disorder Society.

Cerebrovascular Risk Factors in Possible or Probable Cerebral Amyloid Angiopathy, Modifier or Bystander?

Goal: Cerebral amyloid angiopathy (CAA) is a frequent cause of atypical intracerebral hemorrhage (ICH) in the elderly. Stroke risk factors such as arterial hypertension (AHT), atrial fibrillation (AFib), diabetes mellitus (DM), and renal dysfunction (RD) are increasingly apparent in these patients. In this retrospective study, we analyzed the presence of these stroke risk factors in different initial CAA presentations comprising cerebral microbleeds (CMB), acute ischemic stroke (AIS), cortical superficial hemosiderosis (cSS), or lobar ICH (LICH) and evaluated their influence on the initial clinical presentation of patients with CAA.

Material and Methods: We identified patients with at least possible CAA defined by the modified Boston criteria admitted to the Department of Neurology or Neurosurgery from 2002 to 2018.

Findings: In the overall cohort of 209 patients, we analyzed the correlation between the number of stroke risk factors and the initial clinical presentation of patients with CAA and could show the high multimorbidity of the collective. There are large differences between the subgroups with different initial clinical presentations, e.g., patients with CMB as initial CAA presentation have the highest number of cerebrovascular risk factors and recurrent AIS, whereas AFib is more frequent in the Neurosurgery Department.

Conclusion: There is a distinct overlap between the subgroups of CAA manifestations and stroke risk factors that need to be verified in larger patient collectives. Since these comorbidities are likely to influence the clinical course of CAA, they represent possible targets for secondary prevention until specific treatment for CAA becomes available.

Current Management and Therapeutic Strategies for Cerebral Amyloid Angiopathy

Cerebral amyloid angiopathy (CAA) is characterized by accumulation of amyloid β (Aβ) in walls of leptomeningeal vessels and cortical capillaries in the brain. The loss of integrity of these vessels caused by cerebrovascular Aβ deposits results in fragile vessels and lobar intracerebral hemorrhages. CAA also manifests with progressive cognitive impairment or transient focal neurological symptoms. Although development of therapeutics for CAA is urgently needed, the pathogenesis of CAA remains to be fully elucidated. In this review, we summarize the epidemiology, pathology, clinical and radiological features, and perspectives for future research directions in CAA therapeutics. Recent advances in mass spectrometric methodology combined with vascular isolation techniques have aided understanding of the cerebrovascular proteome. In this paper, we describe several potential key CAA-associated molecules that have been identified by proteomic analyses (apolipoprotein E, clusterin, SRPX1 (sushi repeat-containing protein X-linked 1), TIMP3 (tissue inhibitor of metalloproteinases 3), and HTRA1 (HtrA serine peptidase 1)), and their pivotal roles in Aβ cytotoxicity, Aβ fibril formation, and vessel wall remodeling. Understanding the interactions between cerebrovascular Aβ deposits and molecules that accumulate with Aβ may lead to discovery of effective CAA therapeutics and to the identification of biomarkers for early diagnosis.

Disturbed balance in the expression of MMP9 and TIMP3 in cerebral amyloid angiopathy-related intracerebral haemorrhage

Cerebral amyloid angiopathy (CAA) is characterized by the deposition of the amyloid β (Aβ) protein in the cerebral vasculature and poses a major risk factor for the development of intracerebral haemorrhages (ICH). However, only a minority of patients with CAA develops ICH (CAA-ICH), and to date it is unclear which mechanisms determine why some patients with CAA are more susceptible to haemorrhage than others. We hypothesized that an imbalance between matrix metalloproteinases (MMPs) and their inhibitors (TIMPs) contributes to vessel wall weakening. MMP9 plays a role in the degradation of various components of the extracellular matrix as well as of Aβ and increased MMP9 expression has been previously associated with CAA. TIMP3 is an inhibitor of MMP9 and increased TIMP3 expression in cerebral vessels has also been associated with CAA. In this study, we investigated the expression of MMP9 and TIMP3 in occipital brain tissue of CAA-ICH cases (n = 11) by immunohistochemistry and compared this to the expression in brain tissue of CAA cases without ICH (CAA-non-haemorrhagic, CAA-NH, n = 18). We showed that MMP9 expression is increased in CAA-ICH cases compared to CAA-NH cases. Furthermore, we showed that TIMP3 expression is increased in CAA cases compared to controls without CAA, and that TIMP3 expression is reduced in a subset of CAA-ICH cases compared to CAA-NH cases. In conclusion, in patients with CAA, a disbalance in cerebrovascular MMP9 and TIMP3 expression is associated with CAA-related ICH.

Absence of Microbleeds Reduces the Risk for Recurrent Intracerebral Hemorrhage

BACKGROUND

Many known risk factors, including hypertension and hyperlipidemia cause intracerebral hemorrhage (ICH). Recently, microbleeds have been identified as one of the factors leading to ICH. While some patients have been found to have recurrent ICH, risk factors for recurrent ICH are scarcely reported. We conducted an observational study on the risk-factors of recurrent ICH, comparing stroke patients with a single hemorrhagic episode and those with recurrent ICH.

METHODS

A retrospective analysis of a single-center database was performed to analyze the clinical presentation and characteristics of patients with a single and recurrent ICH. From January 2016 to December 2017, a total of 317 patients were analyzed based on suspected factors including patients' sex, age, medical history, antiplatelet therapy use, and presence of microbleeds on images.

RESULTS

Of the 317 patients, 36 patients (11.4%) developed a second episode of cerebral hemorrhage. Brain magnetic resonance imaging (MRI) of the patients without microbleeds, predicted reduced risk of recurrence. This is the first report strongly associating the presence of microbleeds with the possibility of a recurrent ICH. Other factors under study did not show an apparent association with recurrent ICH probably because of the high statistical significance obtained with the presence of microbleeds.

CONCLUSION

Our findings revealed that the absence of microbleeds on images is a factor that strongly predicts a reduced risk for recurrent ICH and that the detection of microbleeds on MRI performed in patients with a single hemorrhagic episode, is useful in defining further therapeutic management. These findings may benefit physicians treating stroke patients.

Effects of Dabigatran in Mouse Models of Aging and Cerebral Amyloid Angiopathy

Oral anticoagulants are a critical component of stroke prevention, but carry a risk of brain hemorrhage. These hemorrhagic complications tend to occur in elderly individuals, especially those with predisposing conditions such as cerebral amyloid angiopathy (CAA). Clinical evidence suggests that non-vitamin K antagonist oral anticoagulants are safer than traditional oral anticoagulants. We analyzed whether the anticoagulant dabigatran produces cerebral microhemorrhage (the pathological substrate of MRI-demonstrable cerebral microbleeds) or intracerebral hemorrhage in aged mice with and without hemorrhage-predisposing angiopathy. We studied aged (22 months old) Tg2576 (a model of CAA) and wild-type (WT) littermate mice. Mice received either dabigatran etexilate (DE) (Tg N = 7; WT N = 10) or vehicle (Tg N = 9; WT N = 7) by gavage for 4 weeks. Anticoagulation effects of DE were confirmed using thrombin time assay. No mice experienced intracerebral hemorrhage. Cerebral microhemorrhage analysis, performed using Prussian-blue and H&E staining, showed no significant change in either number or size of cerebral microhemorrhage in DE-treated animals. Analysis of biochemical parameters for endothelial activation (ICAM-1), blood-brain barrier disruption (IgG, claudin-5, fibrinogen), microglial activation (Iba-1), or astrocyte activation (GFAP) showed neither exacerbation nor protective effects of DE in either Tg2576 or WT mice. Our study provides histological and biochemical evidence that aged mice, with or without predisposing factors for brain hemorrhage, tolerate anticoagulation with dabigatran. The absence of dabigatran-induced intracerebral hemorrhage or increased frequency of acute microhemorrhage may provide some reassurance for its use in high-risk patient populations.

Long-Term Follow-Up of Cerebral Amyloid Angiopathy-Associated Intracranial Hemorrhage Reveals a High Prevalence of Atrial Fibrillation

GOAL

Cerebral amyloid angiopathy (CAA) is the second-most common cause of nontraumatic intracerebral hemorrhages (ICH), surpassed only by uncontrolled hypertension. We characterized the percentage, risk factors, and comorbidities of patients suffering from CAA-related ICH in relation to long-term outcomes.

MATERIAL AND METHODS

We performed retrospective analyses and clinical follow-ups of individuals suffering from ICH who were directly admitted to neurosurgery between 2002 and 2016.

FINDINGS

Seventy-four of 174 (42%) spontaneous nontraumatic lobar ICH cases leastwise satisfied the modified Boston criteria definition for at least "possible CAA." Females suffered a higher risk of CAA-caused ICH (42 of 74, 56.8%, P= .035). Atrial fibrillation as a major comorbidity was observed in 19 patients (25.7%). Recovery (decrease of modified Rankin scale [mRS]) was highest during hospitalization in the acute clinic. One-year mortality was as follows: 14 of 25 patients (56%) with probable CAA without supporting pathology, 6 of 18, and 8 of 31 patients with supporting pathology and possible CAA, respectively. Only 10 of 74 (13.6%) had favorable long-term outcomes (mRS ≤2). Increasing numbers of lobar hemorrhages, low initial Glasgow Coma Scale, and subarachnoid hemorrhage were significantly associated with poor survivability, whereas statins, antithrombotic agents, an intraventricular hemorrhage, and midline shift played seemingly minor roles.

CONCLUSIONS

Symptomatic ICH is a serious stage in CAA progression with high mortality. The high incidence of concurrent atrial fibrillation in these patients may support data on more widespread vascular pathology in CAA.

The intracerebral hemorrhage blood transcriptome in humans differs from the ischemic stroke and vascular risk factor control blood transcriptomes

Understanding how the blood transcriptome of human intracerebral hemorrhage (ICH) differs from ischemic stroke (IS) and matched controls (CTRL) will improve understanding of immune and coagulation pathways in both disorders. This study examined RNA from 99 human whole-blood samples using GeneChip® HTA 2.0 arrays to assess differentially expressed transcripts of alternatively spliced genes between ICH, IS and CTRL. We used a mixed regression model with FDR-corrected p(Dx) < 0.2 and p < 0.005 and |FC| > 1.2 for individual comparisons. For time-dependent analyses, subjects were divided into four time-points: 0(CTRL), <24 h, 24-48 h, >48 h; 489 transcripts were differentially expressed between ICH and CTRL, and 63 between IS and CTRL. ICH had differentially expressed T-cell receptor and CD36 genes, and iNOS, TLR, macrophage, and T-helper pathways. IS had more non-coding RNA. ICH and IS both had angiogenesis, CTLA4 in T lymphocytes, CD28 in T helper cells, NFAT regulation of immune response, and glucocorticoid receptor signaling pathways. Self-organizing maps revealed 4357 transcripts changing expression over time in ICH, and 1136 in IS. Understanding ICH and IS transcriptomes will be useful for biomarker development, treatment and prevention strategies, and for evaluating how well animal models recapitulate human ICH and IS.

Fluid-Blood Level and Hematoma Expansion in a Cerebral Amyloid Angiopathy-Associated Intracerebral Hematoma

Patient: Male, 77

Final Diagnosis: Cerebral amyloid angiopathy

Symptoms: Aphasia • hemiparesis

Medication: —

Clinical Procedure: Hematoma evacuation

Specialty: Neurosurgery

An update on neurocritical care for intracerebral hemorrhage

Introduction: Intracerebral hemorrhage remains one of the leading causes of death and disability worldwide with few established interventions that improve neurologic outcome. Research dedicated to better understanding and treating hemorrhagic strokes has multiplied in the past decade. Areas Covered: This review aims to discuss the current landscape of management of intracerebral hemorrhage in a critical care setting and provide updates regarding developments in therapeutic interventions and targets. PubMed was utilized to review recent literature, with a focus on large trials and meta-analyses, which have shaped current practice. Published committee guidelines were also included. A focus was placed on research published after 2015 in an effort to supplement previous reviews included in this publication. Expert Opinion: Literature pertaining to ICH management has allowed for a greater understanding of ineffective strategies as opposed to those of benefit. Despite this, mortality has improved worldwide, which may be the result of growing research efforts. Areas of future research that will impact mortality and improve neurologic outcomes include prevention of hematoma expansion, optimization of blood pressure targets, effective coagulopathy reversal, and minimally invasive surgical techniques to reduce hematoma burden.

Role and mechanisms of cytokines in the secondary brain injury after intracerebral hemorrhage

Intracerebral hemorrhage (ICH) is a common and severe cerebrovascular disease that has high mortality. Few survivors achieve self-care. Currently, patients receive only symptomatic treatment for ICH and benefit poorly from this regimen. Inflammatory cytokines are important participants in secondary injury after ICH. Increases in proinflammatory cytokines may aggravate the tissue injury, whereas increases in anti-inflammatory cytokines might be protective in the ICH brain. Inflammatory cytokines have been studied as therapeutic targets in a variety of acute and chronic brain diseases; however, studies on ICH are limited. This review summarizes the roles and functions of various pro- and anti-inflammatory cytokines in secondary brain injury after ICH and discusses pathogenic mechanisms and emerging therapeutic strategies and directions for treatment of ICH.

Similar outcomes between vitamin K and non-vitamin K antagonist oral anticoagulants associated intracerebral hemorrhage

BACKGROUND

The application of non-vitamin K antagonist oral anticoagulant (NOAC) reduces the risk of intracerebral hemorrhage (ICH) in comparison with vitamin K antagonist (VKA). However, the features and outcomes of NOAC-associated ICH are still unclear, especially for Asian populations.

METHODS

We retrospectively analyzed 49 consecutive patients who had spontaneous ICH while using NOAC or VKA. We compared the clinical characteristics, ICH volume, 7-day and 3-month mortality, and functional outcomes at discharge and 3 months post-stroke using the modified Rankin Scale (mRS) between NOAC- and VKA-associated ICH. The clinical features, ICH volume, ICH location, and/or treatment methods were statistically adjusted.

RESULTS

Among the 49 ICH patients, 15 (30.6%) were using NOAC and 34 (69.4%) were taking VKA. There were no significant differences in the initial ICH volume between groups (mean volume 34.2 ± 43.8 vs. 59.4 ± 46.5 mL, p = 0.061). The percentage of early mortality (within 7 days post-ICH) was significantly lower in the NOAC group (13.3% vs. 44.1%; p = 0.047), but the 3-month mortality was similar (33.3% vs. 47.1%; p = 0.294). The functional outcome was equally poor in both groups at discharge (p = 0.670) and 3 months post-ICH (mean mRS score 4.7 ± 1.3 vs. 4.6 ± 1.7, p = 0.766).

CONCLUSION

There were no significant differences in initial ICH volume, 90-day mortality, or functional outcomes between NOAC and VKA-associated ICH in Asians.

Inflammatory, regulatory, and autophagy co-expression modules and hub genes underlie the peripheral immune response to human intracerebral hemorrhage

BACKGROUND

Intracerebral hemorrhage (ICH) has a high morbidity and mortality. The peripheral immune system and cross-talk between peripheral blood and brain have been implicated in the ICH immune response. Thus, we delineated the gene networks associated with human ICH in the peripheral blood transcriptome. We also compared the differentially expressed genes in blood following ICH to a prior human study of perihematomal brain tissue.

METHODS

We performed peripheral blood whole-transcriptome analysis of ICH and matched vascular risk factor control subjects (n = 66). Gene co-expression network analysis identified groups of co-expressed genes (modules) associated with ICH and their most interconnected genes (hubs). Mixed-effects regression identified differentially expressed genes in ICH compared to controls.

RESULTS

Of seven ICH-associated modules, six were enriched with cell-specific genes: one neutrophil module, one neutrophil plus monocyte module, one T cell module, one Natural Killer cell module, and two erythroblast modules. The neutrophil/monocyte modules were enriched in inflammatory/immune pathways; the T cell module in T cell receptor signaling genes; and the Natural Killer cell module in genes regulating alternative splicing, epigenetic, and post-translational modifications. One erythroblast module was enriched in autophagy pathways implicated in experimental ICH, and NRF2 signaling implicated in hematoma clearance. Many hub genes or module members, such as IARS, mTOR, S1PR1, LCK, FYN, SKAP1, ITK, AMBRA1, NLRC4, IL6R, IL17RA, GAB2, MXD1, PIK3CD, NUMB, MAPK14, DDX24, EVL, TDP1, ATG3, WDFY3, GSK3B, STAT3, STX3, CSF3R, PIP4K2A, ANXA3, DGAT2, LRP10, FLOT2, ANK1, CR1, SLC4A1, and DYSF, have been implicated in neuroinflammation, cell death, transcriptional regulation, and some as experimental ICH therapeutic targets. Gene-level analysis revealed 1225 genes (FDR p < 0.05, fold-change > |1.2|) have altered expression in ICH in peripheral blood. There was significant overlap of the 1225 genes with dysregulated genes in human perihematomal brain tissue (p = 7 × 10-3). Overlapping genes were enriched for neutrophil-specific genes (p = 6.4 × 10-08) involved in interleukin, neuroinflammation, apoptosis, and PPAR signaling.

CONCLUSIONS

This study delineates key processes underlying ICH pathophysiology, complements experimental ICH findings, and the hub genes significantly expand the list of novel ICH therapeutic targets. The overlap between blood and brain gene responses underscores the importance of examining blood-brain interactions in human ICH.

Cerebrovascular pathology in cerebral amyloid angiopathy presenting as intracerebral haemorrhage

Cerebral amyloid angiopathy (CAA) is the second most common cause of non-traumatic intracerebral haemorrhage (ICH) accounting for 12-15% of lobar haemorrhages in the elderly. Definitive diagnosis of CAA requires histological evaluation. We aimed to evaluate the spectrum of cerebrovascular changes in CAA-related ICH. Between 2011 and 2015, biopsy-confirmed cases of CAA were retrieved and clinical, radiological and pathological features were reviewed. The spectrum of vascular alterations was evaluated and amyloid deposition was graded in accordance with the Greenberg and Vonsattel scale. Seven cases of sporadic CAA [5 males and 2 females] were diagnosed, none of whom were suspected to have CAA pre-operatively. Six presented with large intracerebral haematoma (ICH) requiring neurosurgical intervention (age range: 56-70 years) and one had episodic headache and multiple microhaemorrhages requiring a diagnostic brain biopsy (45 years). In the presence of large ICH, vascular amyloid deposits were of moderate to severe grade (grade 4 in 4, grades 2 and 3 in 1 case each) with predominant involvement of medium (200-500 μm) to large (> 500 μm) leptomeningeal vessels. Fibrinoid necrosis was noted in four. Two were hypertensive and on antiplatelet agents. β-Amyloid plaques were detected in two, one of whom had symptomatic dementia. MRI performed in 3 of 6 cases with ICH did not reveal any microhaemorrhages. Amyloid deposits in small (50-200 μm) to medium (200-500 μm) calibre intracortical vessels produced parenchymal microhemorrhages. Histopathological examination of ICH is essential for diagnosing CAA. The vascular calibre rather than grade of amyloid deposits dictates size of the bleed. Presence of co-morbidities such as antiplatelet agents may predispose to haemorrhage.

Diagnosis and Treatment of Primary Central Nervous System Angiitis

PURPOSE OF REVIEW

Primary central nervous system angiitis (PCNSA) is a rare disease. Varying clinical pictures coupled with lack of sensitive and specific diagnostic tests lead to challenges in management of these patients. This unfortunately may lead to both under- or over-diagnosis and unnecessary treatment. It is important to recognize the different conditions that may mimic the clinical and radiologic presentation. We present a contemporary literature review that should update physicians who encounter this patient population.

RECENT FINDINGS

Recent additions to the literature in form of case reports and single-center series show that digital subtraction angiography was the most widely used test to diagnose PCNSA. It is also important to note that brain biopsy is still considered "gold standard" and should be pursued as it not only has information that establishes the diagnosis but also may help in ruling out the diagnosis from mimics. In around 39% of suspected cases, an alternate diagnosis was eventually confirmed highlighting the importance of a comprehensive work-up. For treatment, almost all the literature supports the use of glucocorticoids as the initial treatment and if the patient has a relapse or develops steroid toxicity then the second most commonly used agent was cyclophosphamide. There are increasing reports of benefits with other agents such as methotrexate, azathioprine, mycophenolate, infliximab, and etanercept. The diagnosis and management of PCNSA continues to be a challenge. Formation of prospective patient registries with continued immunologic research for novel targets and immunomodulatory modalities may hold promise for future care of these patients.

Brain Injury Lesion Imaging Using Preconditioned Quantitative Susceptibility Mapping without Skull Stripping

BACKGROUND AND PURPOSE

Identifying cerebral microhemorrhage burden can aid in the diagnosis and management of traumatic brain injury, stroke, hypertension, and cerebral amyloid angiopathy. MR imaging susceptibility-based methods are more sensitive than CT for detecting cerebral microhemorrhage, but methods other than quantitative susceptibility mapping provide results that vary with field strength and TE, require additional phase maps to distinguish blood from calcification, and depict cerebral microhemorrhages as bloom artifacts. Quantitative susceptibility mapping provides universal quantification of tissue magnetic property without these constraints but traditionally requires a mask generated by skull-stripping, which can pose challenges at tissue interphases. We evaluated the preconditioned quantitative susceptibility mapping MR imaging method, which does not require skull-stripping, for improved depiction of brain parenchyma and pathology.

MATERIALS AND METHODS

Fifty-six subjects underwent brain MR imaging with a 3D multiecho gradient recalled echo acquisition. Mask-based quantitative susceptibility mapping images were created using a commonly used mask-based quantitative susceptibility mapping method, and preconditioned quantitative susceptibility images were made using precondition-based total field inversion. All images were reviewed by a neuroradiologist and a radiology resident.

RESULTS

Ten subjects (18%), all with traumatic brain injury, demonstrated blood products on 3D gradient recalled echo imaging. All lesions were visible on preconditioned quantitative susceptibility mapping, while 6 were not visible on mask-based quantitative susceptibility mapping. Thirty-one subjects (55%) demonstrated brain parenchyma and/or lesions that were visible on preconditioned quantitative susceptibility mapping but not on mask-based quantitative susceptibility mapping. Six subjects (11%) demonstrated pons artifacts on preconditioned quantitative susceptibility mapping and mask-based quantitative susceptibility mapping; they were worse on preconditioned quantitative susceptibility mapping.

CONCLUSIONS

Preconditioned quantitative susceptibility mapping MR imaging can bring the benefits of quantitative susceptibility mapping imaging to clinical practice without the limitations of mask-based quantitative susceptibility mapping, especially for evaluating cerebral microhemorrhage-associated pathologies, such as traumatic brain injury.

Challenges for intraventricular hemorrhage research and emerging therapeutic targets

INTRODUCTION

Intraventricular hemorrhage (IVH) affects both premature infants and adults. In both demographics, it has high mortality and morbidity. There is no FDA approved therapy that improves neurological outcome in either population highlighting the need for additional focus on therapeutic targets and treatments emerging from preclinical studies. Areas covered: IVH induces both initial injury linked to the physical effects of the blood (mass effect) and secondary injury linked to the brain response to the hemorrhage. Preclinical studies have identified multiple secondary injury mechanisms following IVH, and particularly the role of blood components (e.g. hemoglobin, iron, thrombin). This review, with an emphasis on pre-clinical IVH research, highlights therapeutic targets and treatments that may be of use in prevention, acute care, or repair of damage. Expert opinion: An IVH is a potentially devastating event. Progress has been made in elucidating injury mechanisms, but this has still to translate to the clinic. Some pathways involved in injury also have beneficial effects (coagulation cascade/inflammation). A greater understanding of the downstream pathways involved in those pathways may allow therapeutic development. Iron chelation (deferoxamine) is in clinical trial for intracerebral hemorrhage and preclinical data suggest it may be a potential treatment for IVH.

Multiple lobar intracerebral hemorrhage and cerebral amyloid angiopathy in the setting of ApoE Є2: a case report of the disease course and call for improved treatment modalities

We describe a case of multiple cerebral amyloid angiopathy-associated intracerebral hemorrhages (ICH) occurring at multi-focal lobar sites of the brain. A review and discussion of the current literature on the importance of Apolipoprotein E (ApoE) genotyping in prediction of ICH outcome and recurrence follows.

Injury mechanisms in acute intracerebral hemorrhage

Intracerebral hemorrhage (ICH) is the most common hemorrhagic stroke subtype, and rates are increasing with an aging population. Despite an increase in research and trials of therapies for ICH, mortality remains high and no interventional therapy has been demonstrated to improve outcomes. We review known mechanisms of injury, recent clinical trial results, and newly discovered signaling pathways involved in hematoma clearance. Enthusiasm remains high for methods of minimally invasive clot removal as well as pharmacologic strategies to improve recovery after ICH, both of which are currently being evaluated in clinical trials. This article is part of the Special Issue entitled 'Cerebral Ischemia'.

Delayed Intracerebral Hemorrhage Secondary to Ventriculoperitoneal Shunt: A Retrospective Study

BACKGROUND

Postoperative delayed intracerebral hemorrhage (DICH) secondary to ventriculoperitoneal (VP) shunt is a rare but severe event. The present study aimed to investigate the incidence and risk factors related to DICH after placement of the VP shunt.

METHODS

The clinical data from 532 patients with VP shunt were collected retrospectively. All clinical variables were examined by univariate analysis, and a binary logistic regression analysis was performed to identify the risk factors related to DICH.

RESULTS

DICH occurred in 20 patients, from 3 to 10 days after placement of the VP shunt. Univariate analysis showed significant differences between the patients with DICH and without DICH with respect to age, history of hypertension, history of craniotomy, and features of the first computed tomography (CT) scans after placement of the VP shunt (all P < 0.05). The binary logistic regression analysis showed that age, history of craniotomy, and features of first CT scans after placement of the VP shunt were independent risk factors for DICH (all P < 0.05). The prognosis for patients with DICH was consistent with the hematoma volume and the neurologic status at the time of hospital admission (all P < 0.05).

CONCLUSIONS

DICH is a rare and potentially severe complication secondary to VP shunt, and a repeat of cranial CT scans after placement of the VP shunt is recommended. Advanced age, craniotomy history, and brain edema around the catheter on the first cranial CT scan after placement of the VP shunt served as independent risk factors for DICH. The patients with DICH with poor neurologic status at the time of hospital admission or large hematoma volume were associated with poor outcome.

Subdural Hemorrhage from Cerebral Amyloid Angiopathy-Related Intracerebral Hemorrhage: A Risk Factor for Postoperative Hemorrhage

OBJECTIVE

Surgical treatment for cerebral amyloid angiopathy (CAA)-related intracerebral hemorrhage (ICH) is controversial. A subset of CAA-related ICH with associated subdural hemorrhage (SDH) has been reported. This study aimed to evaluate clinical results and surgical outcomes of this type of ICH with associated SDH.

METHODS

Study participants included 98 patients with CAA-related ICH who met Boston criteria. Patients were divided into an SDH group and a control (no SDH) group. Clinical and neuroimaging features and surgical outcomes of the 2 groups were compared.

RESULTS

Lobular shape of hematoma was found significantly more often in the SDH group (65.7% [23/35]) compared with the control group (25.4% [16/63]; P < 0.001). Subarachnoid hemorrhage was found significantly more often in the SDH group (34.3% [12/35]) compared with the control group (7.9% [5/63]; P = 0.001). The rate of postoperative hemorrhage was significantly higher in the SDH group (61.5% [8/13]) than in the control group (16.2% [6/37]; P = 0.006). The frequency of occurrence of postoperative hemorrhage was significantly higher in the SDH group (13/13) than in the control group (6/37; P = 0.017). A good surgical outcome occurred in none (0/12) of the patients in the SDH group, whereas a good surgical outcome occurred in 51.9% (14/27) of patients in the control group (P = 0.006).

CONCLUSIONS

Patients with CAA-related ICH with associated SDH more frequently have postoperative hemorrhage and have a worse surgical outcome. These findings are useful in choosing therapeutic methods and preoperative planning of surgical strategy.

Hereditary cerebral small vessel disease and stroke

Cerebral small vessel disease is considered hereditary in about 5% of patients and is characterized by lacunar infarcts and white matter hyperintensities on MRI. Several monogenic hereditary diseases causing cerebral small vessel disease and stroke have been identified. The purpose of this systematic review is to provide a guide for determining when to consider molecular genetic testing in patients presenting with small vessel disease and stroke. CADASIL, CARASIL, collagen type IV mutations (including PADMAL), retinal vasculopathy with cerebral leukodystrophy, Fabry disease, hereditary cerebral hemorrhage with amyloidosis, and forkhead box C1 mutations are described in terms of genetics, pathology, clinical manifestation, imaging, and diagnosis. These monogenic disorders are often characterized by early-age stroke, but also by migraine, mood disturbances, vascular dementia and often gait disturbances. Some also present with extra-cerebral manifestations such as microangiopathy of the eyes and kidneys. Many present with clinically recognizable syndromes. Investigations include a thorough family medical history, medical history, neurological examination, neuroimaging, often supplemented by specific examinations e.g of the of vision, retinal changes, as well as kidney and heart function. However molecular genetic analysis is the final gold standard of diagnosis. There are increasing numbers of reports on new monogenic syndromes causing cerebral small vessel disease. Genetic counseling is important. Enzyme replacement therapy is possible in Fabry disease, but treatment options remain overall very limited.

Rapidly Sequential and Fatal Hemorrhaging in a Case of Cerebral Amyloid Angiopathy

BACKGROUND Cerebral amyloid angiopathy (CAA) is an increasingly recognized cause of lobar intracerebral hemorrhage (ICH) and cognitive impairment in the aging population. Magnetic resonance imaging (MRI) of cerebral microbleeds is the most reliable option for clinical diagnosis of suspected CAA. The pathophysiology of microbleeds and ICH in CAA is not well understood, but it is thought to be the result of vessel weakening and rupture secondary to amyloid deposition. Little evidence has been established pertaining to the time course of recurrent CAA-related microbleeds or larger hemorrhages. Although several risk factors have been associated with an increased risk of ICH in CAA, there are no current treatment guidelines for recurrent hemorrhaging in CAA. CASE REPORT We present a rare case of rapidly sequential and fatal lobar hemorrhaging in the setting of suspected CAA, diagnosed by numerous microbleeds on MRI, compounded by the use of subcutaneous heparin in a 63-year-old female patient. CONCLUSIONS This case broadens our understanding of a rarely identified progression of CAA and illustrates the need for further investigation of the use of subcutaneous heparin in the setting of probable CAA.

Novel Bivalent 99mTc-Complex with N-Methyl-Substituted Hydroxamamide as Probe for Imaging of Cerebral Amyloid Angiopathy

Cerebral amyloid angiopathy (CAA) is characterized by the deposition of amyloid aggregates in the walls of the cerebral vasculature. Recently, the development of molecular imaging probes targeting CAA has been attracting much attention. We previously reported the ^99mTc-hydroxamamide (^99mTc-Ham) complex with a bivalent benzothiazole scaffold as a binding moiety for amyloid aggregates ([^99mTc]BT2) and its utility for CAA-specific imaging. However, the simultaneous generation of two radiolabeled complexes derived from the geometric isomers was observed in the ^99mTc-labeling reaction. It was recently reported that the complexation reaction of ⁹⁹Tc with N-methyl-substituted Ham provided a single ⁹⁹Tc-Ham complex consisting of two N-methylated Ham ligands with marked stability. In this article, we designed and synthesized a novel N-methylated bivalent ^99mTc-Ham complex ([^99mTc]MBT2) and evaluated its utility for CAA-specific imaging. N-Methyl substitution of [^99mTc]BT2 prevented the generation of its isomer in the ^99mTc-labeling reaction. Enhanced in vitro stability of [^99mTc]MBT2 as compared with [^99mTc]BT2 was observed. [^99mTc]MBT2 showed very low brain uptake, which is favorable for CAA-specific imaging. An in vitro inhibition assay using β-amyloid aggregates and in vitro autoradiographic examination of brain sections from a Tg2576 mouse and a CAA patient showed a decline in the binding affinity for amyloid aggregates due to N-methylation of the ^99mTc-Ham complex. These results suggest that the scaffold of the ^99mTc-Ham complex may play important roles in the in vitro stability and the binding affinity for amyloid aggregates.

Imaging of Cerebral Amyloid Angiopathy with Bivalent (99m)Tc-Hydroxamamide Complexes

Cerebral amyloid angiopathy (CAA), characterized by the deposition of amyloid aggregates in the walls of cerebral vasculature, is a major factor in intracerebral hemorrhage and vascular cognitive impairment and is also associated closely with Alzheimer’s disease (AD). We previously reported ^99mTc-hydroxamamide (^99mTc-Ham) complexes with a bivalent amyloid ligand showing high binding affinity for β-amyloid peptide (Aβ(1–42)) aggregates present frequently in the form in AD. In this article, we applied them to CAA-specific imaging probes, and evaluated their utility for CAA-specific imaging. In vitro inhibition assay using Aβ(1–40) aggregates deposited mainly in CAA and a brain uptake study were performed for ^99mTc-Ham complexes, and all ^99mTc-Ham complexes with an amyloid ligand showed binding affinity for Aβ(1–40) aggregates and very low brain uptake. In vitro autoradiography of human CAA brain sections and ex vivo autoradiography of Tg2576 mice were carried out for bivalent ^99mTc-Ham complexes ([^99mTc]SB2A and [^99mTc]BT2B), and they displayed excellent labeling of Aβ depositions in human CAA brain sections and high affinity and selectivity to CAA in transgenic mice. These results may offer new possibilities for the development of clinically useful CAA-specific imaging probes based on the ^99mTc-Ham complex.