Pathophysiology and genetic factors in moyamoya disease

Characterization of PANoptosis-related genes and the immune landscape in moyamoya disease

Moyamoya disease (MMD) is a cerebrovascular narrowing and occlusive condition characterized by progressive stenosis of the terminal portion of the internal carotid artery and the formation of an abnormal network of dilated, fragile perforators at the base of the brain. However, the role of PANoptosis, an apoptotic mechanism associated with vascular disease, has not been elucidated in MMD. In our study, a total of 40 patients' genetic data were included, and a total of 815 MMD-related differential genes were screened, including 215 upregulated genes and 600 downregulated genes. Among them, DNAJA3, ESR1, H19, KRT18 and STK3 were five key genes. These five key genes were associated with a variety of immune cells and immune factors. Moreover, GSEA (gene set enrichment analysis) and GSVA (gene set variation analysis) showed that the different expression levels of the five key genes affected multiple signaling pathways associated with MMD. In addition, they were associated with the expression of MMD-related genes. Then, based on the five key genes, a transcription factor regulatory network was constructed. In addition, targeted therapeutic drugs against MMD-related genes were obtained by the Cmap drug prediction method: MST-312, bisacodyl, indirubin, and tropanyl-3,5-dimethylbenzoate. These results suggest that the PANoptosis-related genes may contribute to the pathogenesis of MMD through multiple mechanisms.

Comprehensive Profiling of Secreted Factors in the Cerebrospinal Fluid of Moyamoya Disease Patients

Moyamoya disease (MMD) is characterized by progressive occlusion of the intracranial internal carotid arteries, leading to ischemic and hemorrhagic events. Significant clinical differences exist between ischemic and hemorrhagic MMD. To understand the molecular profiles in the cerebrospinal fluid (CSF) of MMD patients, we investigated 62 secreted factors in both MMD subtypes (ischemic and hemorrhagic) and examined their relationship with preoperative perfusion status, the extent of postoperative angiographic revascularization, and functional outcomes. Intraoperative CSF was collected from 32 control and 71 MMD patients (37 ischemic and 34 hemorrhagic). Multiplex Luminex assay analysis showed that 41 molecules were significantly elevated in both MMD subtypes when compared to controls, including platelet-derived growth factor-BB (PDGF-BB), plasminogen activator inhibitor 1 (PAI-1), and intercellular adhesion molecule 1 (ICAM1) (p < 0.001). Many of these secreted proteins have not been previously reported in MMD, including interleukins (IL-2, IL-4, IL-5, IL-7, IL-8, IL-9, IL-17, IL-18, IL-22, and IL-23) and C-X-C motif chemokines (CXCL1 and CXCL9). Pathway analysis indicated that both MMD subtypes exhibited similar cellular/molecular functions and pathways, including cellular activation, migration, and inflammatory response. While neuroinflammation and dendritic cell pathways were activated in MMD patients, lipid signaling pathways involving nuclear receptors, peroxisome proliferator-activated receptor (PPAR), and liver X receptors (LXR)/retinoid X receptors (RXR) signaling were inhibited. IL-13 and IL-2 were negatively correlated with preoperative cerebral perfusion status, while 7 factors were positively correlated with the extent of postoperative revascularization. These elevated cytokines, chemokines, and growth factors in CSF may contribute to the pathogenesis of MMD and represent potential future therapeutic targets.

Identification of diagnostic markers for moyamoya disease by combining bulk RNA-sequencing analysis and machine learning

Moyamoya disease (MMD) remains a chronic progressive cerebrovascular disease with unknown etiology. A growing number of reports describe the development of MMD relevant to infection or autoimmune diseases. Identifying biomarkers of MMD is to understand the pathogenesis and development of novel targeted therapy and may be the key to improving the patient's outcome. Here, we analyzed gene expression from two GEO databases. To identify the MMD biomarkers, the weighted gene co-expression network analysis (WGCNA) and the differential expression analyses were conducted to identify 266 key genes. The KEGG and GO analyses were then performed to construct the protein interaction (PPI) network. The three machine-learning algorithms of support vector machine-recursive feature elimination (SVM-RFE), random forest and least absolute shrinkage and selection operator (LASSO) were used to analyze the key genes and take intersection to construct MMD diagnosis based on the four core genes found (ACAN, FREM1, TOP2A and UCHL1), with highly accurate AUCs of 0.805, 0.903, 0.815, 0.826. Gene enrichment analysis illustrated that the MMD samples revealed quite a few differences in pathways like one carbon pool by folate, aminoacyl-tRNA biosynthesis, fat digestion and absorption and fructose and mannose metabolism. In addition, the immune infiltration profile demonstrated that ACAN expression was associated with mast cells resting, FREM1 expression was associated with T cells CD4 naive, TOP2A expression was associated with B cells memory, UCHL1 expression was associated with mast cells activated. Ultimately, the four key genes were verified by qPCR. Taken together, our study analyzed the diagnostic biomarkers and immune infiltration characteristics of MMD, which may shed light on the potential intervention targets of moyamoya disease patients.

[Moyamoya disease in adults: treatment methods in modern era]

Moyamoya angiopathy is a chronic progressive cerebrovascular disease characterized by stenosis and occlusion of the distal segments of the internal carotid arteries and/or proximal segments of the middle and anterior cerebral arteries, with a gradual compensatory restructuring of the cerebral circulation to the system of the external carotid arteries. Today, the main treatment method for Moyamoya angiopathy is surgical revascularization of the brain. A search and analysis of publications on the treatment of adult patients with Moyamoya angiopathy was carried out in the PubMed and Medscape databases over the past 10 years. We present a case of an adult female patient with a hemorrhagic form of Moyamoya angiopathy stage IV according to J. Suzuki, who underwent staged combined revascularization of both cerebral hemispheres. Surgical revascularization included the creation of a low-flow extra-intracranial shunt combined with a combination of indirect synangiosis. The combination of direct and indirect methods of surgical revascularization enables to achieve the development of an extensive network of collaterals and fully compensate for cerebral circulatory disorders both in the early and late postoperative periods, which is confirmed by instrumental diagnostic data. Combined revascularization is the most effective modern method of treating patients with Moyamoya angiopathy due to the complementary influence of direct and indirect components of revascularization.

Clinical Features and Risk Factors of Postoperative Stroke in Adult Moyamoya Disease

BACKGROUND AND PURPOSE

The clinical features of and risk factors for postoperative stroke after surgical revascularization in adult moyamoya disease (MMD) have not been fully elucidated. To this end, the baseline clinical features were hereby described, and the risk factors for postoperative stroke were determined.

METHODS

Data of 4078 MMD inpatients were collected retrospectively across all secondary- and higher-level hospitals of Hubei Province from January 2019 to December 2020. In accordance with inclusion and exclusion criteria, 559 adult MMD inpatients were finally enrolled. The associated characteristics and potential risk factors were analyzed, and the Kaplan-Meier risk of stroke was also calculated.

RESULTS

The patients consisted of 286 females and 273 males, with a mean age of 49.1 ± 10.0 years, all of whom had at least 1 year of follow-up (median 25.1 months). There were 356 cases of preoperative ischemic symptoms and 203 cases of preoperative hemorrhage symptoms. Indirect, direct, and combined revascularization were conducted on 97, 105 and 357 patients, respectively. Among these patients, 17 had postoperative hemorrhagic stroke (PHS), and 43 had postoperative ischemic stroke (PIS). A comparison between PHS/PIS group and control group (patients without postoperative stroke events) showed that preoperative hemorrhage was significantly associated with PHS (p = 0.003), while hypertension (p = 0.003), diabetes mellitus (p = 0.003) and modified Rankin scale (mRS) (p = 0.034) at admission were associated with a higher rate of PIS. Furthermore, preoperative hemorrhagic stroke was identified as a risk factor for PHS (odds ratio [OR], 4.229 [95% CI, 1.244-14.376]; p = 0.021), while hypertension (odds ratio [OR], 0.424 [95% CI, 0.210-0.855]; p = 0.017), diabetes mellitus (odds ratio [OR], 0.368 [95% CI, 0.163-0.827]; p = 0.016) and admission mRS (odds ratio [OR], 2.301 [95% CI, 1.157-4.575]; p = 0.017) were found to be risk factors for PIS.

CONCLUSIONS

The age distribution of adult MMD patients with revascularization was predominantly concentrated within the range from 46 to 55 years. Preoperative hemorrhage events were considered the risk factor for PHS. Hypertension, diabetes and admission mRS were correlated with PIS, and were also the risk factors for PIS. These results indicated the possible contribution of enhancing systematic disease management to the prevention of postoperative cerebrovascular accidents.

APOE as potential biomarkers of moyamoya disease

Objective

The mechanisms underpinning Moyamoya disease (MMD) remain unclear, and effective biomarkers remain unknown. The purpose of this study was to identify novel serum biomarkers of MMD.

Methods

Serum samples were collected from 23 patients with MMD and 30 healthy controls (HCs). Serum proteins were identified using tandem tandem-mass-tag (TMT) labeling combined with liquid chromatography-tandem mass spectrometry (LC-MS/MS). Differentially expressed proteins (DEPs) in the serum samples were identified using the SwissProt database. The DEPs were assessed using the Kyoto Encyclopedia of Genes and Genomes (KEGG) database, Gene Ontology (GO), and protein-protein interaction (PPI) networks, and hub genes were identified and visualized using Cytoscape software. Microarray datasets GSE157628, GSE189993, and GSE100488 from the Gene Expression Omnibus (GEO) database were collected. Differentially expressed genes (DEGs) and differentially expressed miRNAs (DE-miRNAs) were identified, and miRNA targets of DEGs were predicted using the miRWalk3.0 database. Serum apolipoprotein E (APOE) levels were compared in 33 MMD patients and 28 Moyamoya syndrome (MMS) patients to investigate the potential of APOE to be as an MMD biomarker.

Results

We identified 85 DEPs, of which 34 were up- and 51 down-regulated. Bioinformatics analysis showed that some DEPs were significantly enriched in cholesterol metabolism. A total of 1105 DEGs were identified in the GSE157628 dataset (842 up- and 263 down-regulated), whereas 1290 were identified in the GSE189993 dataset (200 up- and 1,090 down-regulated). The APOE only overlaps with the upregulated gene expression in Proteomic Profiling and in GEO databases. Functional enrichment analysis demonstrated that APOE was associated with cholesterol metabolism. Moreover, 149 miRNAs of APOE were predicted in the miRWalk3.0 database, and hsa-miR-718 was the only DE-miRNA overlap identified in MMD samples. Serum APOE levels were significantly higher in patients with MMD than in those without. The performance of APOE as an individual biomarker to diagnose MMD was remarkable.

Conclusions

We present the first description of the protein profile of patients with MMD. APOE was identified as a potential biomarker for MMD. Cholesterol metabolism was found to potentially be related to MMD, which may provide helpful diagnostic and therapeutic insights for MMD.

CircZXDC Promotes Vascular Smooth Muscle Cell Transdifferentiation via Regulating miRNA-125a-3p/ABCC6 in Moyamoya Disease

Moyamoya disease (MMD) is an occlusive, chronic cerebrovascular disease affected by genetic mutation and the immune response. Furthermore, vascular smooth muscle cells (VSMCs) and endothelial cells (ECs) participate in the neointima of MMD, but the etiology and pathophysiological changes in MMD vessels remain largely unknown. Therefore, we established the circZXDC (ZXD family zinc finger C)-miR-125a-3p-ABCC6 (ATP-binding cassette subfamily C member 6) axis from public datasets and online tools based on "sponge-like" interaction mechanisms to investigate its possible role in VSMCs. The results from a series of in vitro experiments, such as dual luciferase reporter assays, cell transfection, CCK-8 assays, Transwell assays, and Western blotting, indicate a higher level of circZXDC in the MMD plasma, especially in those MMD patients with the RNF213 mutation. Moreover, circZXDC overexpression results in a VSMC phenotype switching toward a synthetic status, with increased proliferation and migration activity. CircZXDC sponges miR-125a-3p to increase ABCC6 expression, which induces ERS (endoplasmic reticulum stress), and subsequently regulates VSMC transdifferentiation from the contractive phenotype to the synthetic phenotype, contributing to the intima thickness of MMD vessels. Our findings provide insight into the pathophysiological mechanisms of MMD and indicate that the circZXDC-miR-125a-3p-ABCC6 axis plays a pivotal role in the progression of MMD. Furthermore, circZXDC might be a diagnostic biomarker and an ABCC6-specific inhibitor and has the potential to become a promising therapeutic option for MMD.

Novel Multifaceted Roles for RNF213 Protein

Ring Finger Protein 213 (RNF213), also known as Mysterin, is the major susceptibility factor for Moyamoya Arteriopathy (MA), a progressive cerebrovascular disorder that often leads to brain stroke in adults and children. Although several rare RNF213 polymorphisms have been reported, no major susceptibility variant has been identified to date in Caucasian patients, thus frustrating the attempts to identify putative therapeutic targets for MA treatment. For these reasons, the investigation of novel biochemical functions, substrates and unknown partners of RNF213 will help to unravel the pathogenic mechanisms of MA and will facilitate variant interpretations in a diagnostic context in the future. The aim of the present review is to discuss novel perspectives regarding emerging RNF213 roles in light of recent literature updates and dissect their relevance for understanding MA and for the design of future research studies. Since its identification, RNF213 involvement in angiogenesis and vasculogenesis has strengthened, together with its role in inflammatory signals and proliferation pathways. Most recent studies have been increasingly focused on its relevance in antimicrobial activity and lipid metabolism, highlighting new intriguing perspectives. The last area could suggest the main role of RNF213 in the proteasome pathway, thus reinforcing the hypotheses already previously formulated that depict the protein as an important regulator of the stability of client proteins involved in angiogenesis. We believe that the novel evidence reviewed here may contribute to untangling the complex and still obscure pathogenesis of MA that is reflected in the lack of therapies able to slow down or halt disease progression and severity.

Moyamoya Disease Susceptibility Gene RNF213 Regulates Endothelial Barrier Function

BACKGROUND

Variants in the ring finger protein 213 (RNF213) gene are known to be associated with increased predisposition to cerebrovascular diseases development. Genomic studies have identified RNF213 as a major risk factor of Moyamoya disease in East Asian descendants. However, little is known about the RNF213 (ring finger protein 213) biological functions or its associated pathogenic mechanisms underlying Moyamoya disease.

METHODS

To investigate RNF213 loss-of-function effect in endothelial cell, stable RNF213-deficient human cerebral endothelial cells were generated using the CRISPR-Cas9 genome editing technology.

RESULTS

In vitro assays, using RNF213 knockout brain endothelial cells, showed clear morphological changes and increased blood-brain barrier permeability. Downregulation and delocalization of essential interendothelial junction proteins involved in the blood-brain barrier maintenance, such as PECAM-1 (platelet endothelial cell adhesion molecule-1), was also observed. Brain endothelial RNF213-deficient cells also showed an abnormal potential to transmigration of leukocytes and secreted high amounts of proinflammatory cytokines.

CONCLUSIONS

Taken together, these results indicate that RNF213 could be a key regulator of cerebral endothelium integrity, whose disruption could be an early pathological mechanism leading to Moyamoya disease. This study also further reinforces the importance of blood-brain barrier integrity in the development of Moyamoya disease and other RNF213-associated diseases.

Acute StrokeTreatment in Children: Are Adult Guidelines Applicable?

Purpose of this Review

This article provides an overview into acute treatments in stroke which are widely studied and available for adults and their applicability in the pediatric population.

Recent Findings

Arterial ischemic stroke is an important cause of morbidity and mortality in the pediatric population. Neurological deficits and etiologies are age-dependent and more challenging to diagnose than in the adult population. Advancements in imaging and treatment modalities including increased treatment windows in acute stroke have led to improvement in the diagnosis and management of pediatric arterial ischemic disease. Accordingly, hyperacute treatments, such as endovascular therapy, are becoming increasingly available in an attempt to improve outcomes in children.

Summary

Significant scientific and technological advances have transformed the hyperacute treatment of stroke in the recent years, allowing for improvement in the diagnosis and treatment of cerebrovascular pathologies in children. Optimization in the approach, and validation of existing stroke pathways/protocols is expected to further advance acute stroke therapy in pediatric patient care. Given that the lifelong individual, family, and societal burden of acute stroke is likely to be greater than in adults because infants and children surviving stroke live more years with disability, we must be knowledgeable about this pathology and the medical and therapeutic options available for this unique population as detailed in this review.

Pathophysiology of Vascular Stenosis and Remodeling in Moyamoya Disease

Moyamoya disease (MMD) and moyamoya syndrome (MMS) are progressive vascular pathologies unique to the cerebrovasculature that are important causes of stroke in both children and adults. The natural history of MMD is characterized by primary progressive stenosis of the supraclinoid internal carotid artery, followed by the formation of fragile collateral vascular networks. In MMS, stenosis and collateralization occur in patients with an associated disease or condition. The pathological features of the stenosis associated with MMD include neointimal hyperplasia, disruption of the internal elastic lamina, and medial attenuation, which ultimately lead to progressive decreases in both luminal and external arterial diameter. Several molecular pathways have been implicated in the pathophysiology of stenosis in MMD with functions in cellular proliferation and migration, extracellular matrix remodeling, apoptosis, and vascular inflammation. Importantly, several of these molecular pathways overlap with those known to contribute to diseases of systemic arterial stenosis, such as atherosclerosis and fibromuscular dysplasia (FMD). Despite these possible shared mechanisms of stenosis, the contrast of MMD with other stenotic pathologies highlights the central questions underlying its pathogenesis. These questions include why the stenosis that is associated with MMD occurs in such a specific and limited anatomic location and what process initiates this stenosis. Further investigation of these questions is critical to developing an understanding of MMD that may lead to disease-modifying medical therapies. This review may be of interest to scientists, neurosurgeons, and neurologists involved in both moyamoya research and treatment and provides a review of pathophysiologic processes relevant to diseases of arterial stenosis on a broader scale.

Implementation and Rationale for a Unified Clinical and Imaging Protocol for Evaluation and Treatment of Moyamoya Angiopathy: A Single Institutional Experience

Moyamoya disease (MMD) is a complex and incompletely-understood cerebrovascular pathological entity that requires thorough clinical and imaging evaluation. Moyamoya is rare, thereby making the establishment of an effective, thorough and interdisciplinary patient evaluation protocol challenging, even within specialized referral centers. Nevertheless, implementation of such a protocol is crucial in order to provide the best possible evaluation and treatment for MMD patients. Here, we describe our institution's implementation of, rationale for, and experience with a comprehensive multidisciplinary collaboration and evaluation strategy for adult patients with moyamoya. This evaluation course consists of, first of all, a thorough clinical and laboratory evaluation with a vascular neurologist. This is followed by a comprehensive imaging assessment which evaluates angiographic and parenchymal features, in addition to cerebrovascular functionality. Finally, appropriate referrals are made to consulting services as indicated, which includes vascular neurosurgery. These steps are described in detail herein.

Cutaneous manifestations in Moyamoya angiopathy: A review

BACKGROUND AND PURPOSE

Moyamoya angiopathy (MA) is a progressive cerebrovascular disease with a poorly understood pathophysiology. It is mainly characterized by progressive bilateral stenosis of the terminal intracranial part of the supraclinoid internal carotid arteries and the proximal parts of the middle and anterior cerebral arteries. This results in early-onset ischemic or hemorrhagic strokes. The disease may be idiopathic (known as Moyamoya disease) or associated with other heritable or acquired conditions, including type 1 neurofibromatosis or other RASopathies, sickle cell disease, Down syndrome, or autoimmune disorders (known as Moyamoya syndrome). Apart from the brain, other organ manifestations including cutaneous ones have also been described in MA patients.

MATERIALS AND METHODS

A literature research on PubMed was performed for articles mentioning the cutaneous association in MA and published between 1994 and October 2020.

CONCLUSION

The present review summarizes the cutaneous associations as well as the coincidental dermatological findings seen in MA patients. Those include changes in the epidermis, dermis, or skin appendages for example café-au-lait spots, hypomelanosis of Ito, livedo racemosa, hemangiomas, premature graying of hair, chilblains etc.

Postoperative Functional Outcomes and Prognostic Factors in Two Types of Adult Moyamoya Diseases

BACKGROUND

To determine the functional outcomes in each period for adult ischemic and hemorrhagic Moyamoya disease (MMD) patients and identify prognostic factors.

METHODS

The current retrospective study reviewed consecutive adult MMD patients surgically treated from January 2012 to June 2017. Perioperative clinical data were collected and follow-up was conducted via telephone interviews. Functional outcomes and prognostic factors were analyzed.

RESULTS

A total of 219 ischemic MMD patients (268 hemispheres) and 157 hemorrhagic patients (193 hemispheres) were included. The median follow-up time was 18 months (3-69 months). MMD type had no significant effect on the modified Rankin Scale(mRS) score at discharge. Perioperative complications (P = 0.004) and the mRS score at baseline (P < 0.001) were risk factors correlated with the short-term functional outcomes in both groups, while diabetes mellitus (DM, P = 0.022) also played a role in the ischemic group. During the follow-up period, functional outcomes obviously improved in both groups, but two groups showed nonproportional cumulative curves for favorable functional outcomes (log-rank test, P = 0.483). Stroke recurrence (P < 0.001) and mRS at discharge (P < 0.001) were common factors related with long-term functional outcomes in two types of MMD patients. Particularly, female patients with ischemic MMD were more likely to have higher mRS scores (P = 0.028) and Suzuki stage was positively associated with long-term functional outcomes in hemorrhagic group (P = 0.044).

CONCLUSIONS

MMD type had no significant effect on prognosis while both types of MMD patients showed overall significant improvements in functional outcomes after surgery. Different types of MMD patients have distinct prognostic factors for short-term and long-term functional outcomes.

Clinical Characteristics of Moyamoya Angiopathy in a Pediatric Cohort

Moyamoya angiopathy is a rare cerebral vasculopathy characterized by a progressive stenosis of the terminal portion of the internal carotid arteries and the development of abnormal collateral vessels. Children with moyamoya angiopathy become symptomatic because of cerebral ischemic complications, and many patients eventually need revascularization. In most pediatric patients with this disease, the etiology is likely genetic. We aim to report clinical characteristics of a single-center cohort of pediatric patients with moyamoya. We performed a retrospective chart review of patients <18 years with angiographically confirmed moyamoya disease evaluated at our institution. An in-house text search tool, Advanced Cohort Explorer, was used to filter electronic medical records for patients with a diagnosis of moyamoya angiopathy from January 1999 to December 2018. The inclusion criteria were age <18 years at the time of onset of disease and a diagnosis confirmed at Mayo clinic. Fifty-one patients met the inclusion criteria. Fifty-five percent of our cohort were male, and the median age was 9 years. Three patients had a family history of moyamoya disease. Approximately half of our patients had bilateral disease. Sixteen patients had a genetic or chromosomal diagnosis (Down syndrome and NF1 being most common). Congenital anomalies like heart defects and renal dysplasia were also noted. This study is unique in that it was a large study on pediatric patients with moyamoya angiopathy. It also highlights the importance of considering genetic syndromes as an underlying cause when moyamoya angiopathy starts early in life.

Impact of Endothelial Shear Stress on the Bilateral Progression of Unilateral Moyamoya Disease

Background and Purpose—

In unilateral moyamoya disease, altered endothelial shear stress on the intact-side terminal internal carotid artery might trigger the progression to bilateral disease. We analyzed the endothelial shear stress parameters of the normally appearing terminal internal carotid artery in unilateral moyamoya disease and its association with the progression to bilateral disease.

Methods—

This retrospective cohort study included patients diagnosed with unilateral moyamoya disease by cerebral angiography and followed-up with regular magnetic resonance imaging/magnetic resonance angiography evaluations for >1 year. Endothelial shear stress parameters acquired were mean and maximum signal intensity gradients (SIG) and SIG SD at the vessel boundary in time-of-flight sequences in initial brain magnetic resonance imaging/magnetic resonance angiography. Contralateral disease progression defined as the detection of newly developed vessel steno-occlusion with an magnetic resonance angiography steno-occlusive stage of ≥2, in the previously intact side of the brain on follow-up magnetic resonance imaging/magnetic resonance angiography evaluation.

Results—

Among 146 patients (66 males [45.2%] and 80 females [54.8%]; 76 pediatric [52.1%]), contralateral disease progression was detected in 43 patients (29.5%) after a mean follow-up of 4.3±2.4 years. Multivariate analysis showed that SIG SD was significantly associated with this progression (odds ratio, 13.001 [95% CI, 1.764−95.794], P =0.012). In receiver operating characteristic curve analysis, SIG SD predicted the contralateral progression with area under the curve values of 0.803 (95% CI, 0.726−0.880, P <0.001). The regression model was reproduced in the external cohort of 31 patients.

Conclusions—

Increased spatial variability of the endothelial shear stress around the normally appearing terminal internal carotid artery, as measured by SIG SD in time-of-flight sequences, may predict the contralateral progression of unilateral moyamoya disease.

Clinical efficacy of extracranial-intracranial bypass for the treatment of adult patients with moyamoya disease: A protocol of systematic review of randomized controlled trials

BACKGROUND

Moyamoya disease (MMD) is a major health concern associated with blocked arteries at the base of the brain. The aim of this study will synthesize the current evidence of the efficacy and safety of extracranial-intracranial bypass (EIB) for the treatment of adult patients with MMD.

METHODS

A systematically and comprehensively literature search will be performed in PubMed, EMBASE, Web of Science, CENTRAL, CINAHL, AMED, CBM, and CNKI to identify relevant randomized controlled trails (RCTs) investigating the efficacy and safety of EIB for treating MMD. We will search all above electronic databases from their inception to the July 30, 2019. Two review authors will independently perform study selection, data extraction, and conduct risk of bias evaluation using Cochrane risk of bias tool. We will also explore heterogeneity across studies. RevMan 5.3 software will be applied for statistical analysis performance.

RESULTS

This study will evaluate the efficacy and safety of EIB for the treatment of adult patients with MMD.

CONCLUSION

The results of this study will provide latest evidence of the efficacy and safety of EIB for MMD.

DISSEMINATION AND ETHICS

This study is based on published studies, thus, no ethical consideration is needed. The results of this study are expected to be published in peer-reviewed journals or will be presented on conference meeting.Systematic review registration: PROSPERO CRD42019155839.

Neuroimaging of vascular reserve in patients with cerebrovascular diseases

Cerebrovascular reactivity, defined broadly as the ability of brain parenchyma to adjust cerebral blood flow in response to altered metabolic demand or a vasoactive stimulus, is being measured with increasing frequency and may have a use for portending new or recurrent stroke risk in patients with cerebrovascular disease. The purpose of this review is to outline (i) the physiological basis of variations in cerebrovascular reactivity, (ii) available approaches for measuring cerebrovascular reactivity in research and clinical settings, and (iii) clinically-relevant cerebrovascular reactivity findings in the context of patients with cerebrovascular disease, including atherosclerotic arterial steno-occlusion, non-atherosclerotic arterial steno-occlusion, anemia, and aging. Literature references summarizing safety considerations for these procedures and future directions for standardizing protocols and post-processing procedures across centers are presented in the specific context of major unmet needs in the setting of cerebrovascular disease.

Association of CD40 SNPs with Moyamoya in a Chinese children population

Background: The etiology of Moyamoya disease (MMD) remains unknown to a large extent. Immune and inflammation dysfunction may play a role in the pathogenesis of this rare disease. Coexisting Kawasaki disease (KD) with MMD were reported and both diseases have a feature of vasculopathy, raising the hypothesis that there may be some common pathologic factors. We investigated single nucleotide polymorphisms (SNPs) previously identified in KD and performed a genetic analysis among Chinese pediatric patients with MMD. Results: We analyzed patients' DNA for the SNPs in B lymphoid tyrosine kinase, CD40, and coatomer protein complex beta-2 subunit, which had been associated with KD by literatures. Genotyping was performed by sequencing the genetic regions containing the SNPs with customized primers. A total of 5 genotype polymorphisms were examined among 48 pediatric MMD cases and 50 healthy controls. The mean age of MMD children was 6.72 ± 3.63 years old, while 7.31 ± 3.79 in controls. We found two SNPs of CD40 were associated with MMD. Polymorphisms rs4813003 major allele CC and rs1535045 minor allele TT were significantly higher in MMD cases. The other SNPs showed no statistical difference between MMD cases and controls. Conclusions: Our findings provide evidence that there may be a relationship between MMD and auto-immune dysfunction. We hypothesize that these genetic features may lead to the pathogenesis within the vascular wall. Further study regarding whether CD40 can function as the personalized target of MMD should be investigated in future.

Acetaminophen Does Not Reduce Postoperative Opiate Consumption in Patients Undergoing Craniotomy for Cerebral Revascularization: A Randomized Control Trial

Background

Postoperative management in patients undergoing craniotomy is unique and challenging. We utilized a population of patients who underwent bilateral extracranial-to-intracranial (EC-IC bypass) revascularization procedures for moyamoya disease and hypothesized that 1 gram (gm) of intravenous (IV) acetaminophen given immediately after intubation and again 45 minutes prior to the end of craniotomy may be more effective than saline in minimizing opiate consumption and decreasing pain scores.

Methods

In a double-blind, randomized, placebo-controlled crossover pilot study, 40 craniotomies in 20 patients were studied. A random number generator assigned patients to receive either 1 gram of IV acetaminophen or an equal volume of normal saline immediately after intubation and again 45 minutes prior to the end of their first operation. For the second surgery, patients received the study drug (IV acetaminophen or normal saline) that they did not receive during their first surgery.

Results

In the IV acetaminophen group, the average 24-hour postoperative fentanyl equivalent consumption was decreased but the difference was not statistically significant: 228 micrograms compared to 312 micrograms in the placebo group (Figure 1; p = 0.09). Pain scores did not significantly differ between the IV acetaminophen group and the placebo group in postoperative hours 0-12 (Figure 2; p = 0.44) or 24 (Figure 3; p = 0.77).

Conclusion

Our study demonstrates that in patients receiving bilateral craniotomies for moyamoya disease, IV acetaminophen when given immediately after intubation and again 45 minutes prior to closure does not significantly decrease 12- or 24-hour postoperative opiate consumption.

Consensus statement on current and emerging methods for the diagnosis and evaluation of cerebrovascular disease

Cerebrovascular disease (CVD) remains a leading cause of death and the leading cause of adult disability in most developed countries. This work summarizes state-of-the-art, and possible future, diagnostic and evaluation approaches in multiple stages of CVD, including (i) visualization of sub-clinical disease processes, (ii) acute stroke theranostics, and (iii) characterization of post-stroke recovery mechanisms. Underlying pathophysiology as it relates to large vessel steno-occlusive disease and the impact of this macrovascular disease on tissue-level viability, hemodynamics (cerebral blood flow, cerebral blood volume, and mean transit time), and metabolism (cerebral metabolic rate of oxygen consumption and pH) are also discussed in the context of emerging neuroimaging protocols with sensitivity to these factors. The overall purpose is to highlight advancements in stroke care and diagnostics and to provide a general overview of emerging research topics that have potential for reducing morbidity in multiple areas of CVD.

Whole exome sequencing identifies MRVI1 as a susceptibility gene for moyamoya syndrome in neurofibromatosis type 1

Background and purpose

Moyamoya angiopathy is a progressive cerebral vasculopathy. The p.R4810K substitution in RNF213 has previously been linked to moyamoya disease in Asian populations. When associated with other medical conditions, such as neurofibromatosis type 1, this vasculopathy is frequently reported as moyamoya syndrome. Intriguingly, most cases of moyamoya-complicated neurofibromatosis type 1 have been described in Caucasians, inverting the population ratio observed in Asians, although prevalence of neurofibromatosis type 1 is constant worldwide. Our aim was to investigate whether, among Caucasians, additive genetic factors may contribute to the occurrence of moyamoya in neurofibromatosis type 1.

Methods

Whole exome sequencing was carried out on an Italian family with moyamoya-complicated neurofibromatosis type 1 to identify putative genetic modifiers independent of the NF1 locus and potentially involved in moyamoya pathogenesis. Results were validated in an unrelated family of German ancestry.

Results

We identified the p.P186S substitution (rs35857561) in MRVI1 that segregated with moyamoya syndrome in both the Italian and German family.

Conclusions

The rs35857561 polymorphism in MRVI1 may be a genetic susceptibility factor for moyamoya in European patients with neurofibromatosis type 1. MRVI1 is a functional partner of ITPR1, PRKG1 and GUCY1A3, which are involved in response to nitric oxide. Mutations in GUCY1A3 have been recently linked to a recessive syndromic form of moyamoya with esophageal achalasia.

When and why is surgical revascularization indicated for the treatment of moyamoya syndrome in patients with RASopathies? A systematic review of the literature and a single institute experience

BACKGROUND

Moyamoya disease (MMD) is a cerebrovascular disorder characterized by the progressive occlusion of the supraclinoid internal carotid artery (ICA), resulting in the formation of an abnormal cerebral vascular network. When MMD occurs in association with an underlying medical condition, including some distinctive genetic disorders, it is named moyamoya syndrome (MMS). The discrimination between MMD and MMS has been validated by recent genetic researches and international reviews. Similarly to patients suffering from MMD, patients with MMS generally become symptomatic because of ischemic complications, which lead to hemiparesis, transient ischemic events, seizures, and sensory symptoms. RASopathies are a group of neurodevelopmental disorders that can be associated with MMS.

RESULTS

We retrospectively reviewed 18 RASopathy patients with MMS treated at our institution from 2000 to 2015 (16 neurofibromatosis type 1, 1 Costello syndrome, and 1 Schimmelpenning syndrome). Here, we report clinical data, performed surgical procedures, and clinic-radiological outcome of these patients. Most of them received both indirect revascularization and medical therapy.

CONCLUSIONS

At the moment, there are no univocal recommendations on which of these two treatment strategies is the treatment of choice in patients with RASopathies and MMS. We suggest that patients with a good overall prognosis (primarily depending on the distinctive underlying genetic disorder) and initial cerebrovascular disease could benefit from a prophylactic surgical revascularization, in order to prevent the cognitive impairment due to the progression of the vasculopathy.

Distinctive facial features in idiopathic Moyamoya disease in Caucasians: a first systematic analysis

Background

Craniofacial dysmorphic features are morphological changes of the face and skull which are associated with syndromic conditions. Moyamoya angiopathy is a rare cerebral vasculopathy that can be divided into Moyamoya syndrome, which is associated or secondary to other diseases, and into idiopathic Moyamoya disease. Facial dysmorphism has been described in rare genetic syndromes with associated Moyamoya syndrome. However, a direct relationship between idiopathic Moyamoya disease with dysmorphic facial changes is not known yet.

Methods

Landmarks were manually placed on frontal photographs of the face of 45 patients with bilateral Moyamoya disease and 50 matched controls. After procrustes alignment of landmarks a multivariate, penalized logistic regression (elastic-net) was performed on geometric features derived from landmark data to classify patients against controls. Classifiers were visualized in importance plots that colorcode importance of geometric locations for the classification decision.

Results

The classification accuracy for discriminating the total patient group from controls was 82.3% (P-value = 6.3×10⁻¹¹, binomial test, a-priori chance 50.2%) for an elastic-net classifier. Importance plots show that differences around the eyes and forehead were responsible for the discrimination. Subgroup analysis corrected for body mass index confirmed a similar result.

Discussion

Results suggest that there is a resemblance in faces of Caucasian patients with idiopathic Moyamoya disease and that there is a difference to matched controls. Replication of findings is necessary as it is difficult to control all residual confounding in study designs such as ours. If our results would be replicated in a larger cohort, this would be helpful for pathophysiological interpretation and early detection of the disease.

Association of Hyperthyroidism and Thyroid Autoantibodies with Moyamoya Disease and Its Stroke Event: A Population-based Case-control Study and Meta-analysis

The aim of this study was to investigate the specific thyroid condition and thyroid autoantibodies in adult moyamoya disease (MMD) according to clinical presentation (ischemia vs. hemorrhage stroke). In addition, a meta-analysis was performed to reveal the association between adult MMD and elevated thyroid function, or autoantibodies. Prospectively collected data on 169 consecutive patients with MMD at a single institution were analyzed. Community-based controls matched for age and sex were selected for comparison. Penalized multinomial logistic regression analysis was used for factors affecting stroke. For meta-analysis, heterogeneity was evaluated by using the I² test. If I² < 50%, a fixed effect model was used. Fifty-four cases (32.0%) presented with ischemic stroke and 37 cases (21.9%) with hemorrhage stroke. Hyperthyroidism had a marginally increased risk of MMD with ischemic stroke with reference value of MMD without stroke [odds ratio (OR), 2.53; P = 0.055]. Anti-thyroperoxidase antibody (TPOAb) increased the risk of MMD presenting with ischemic stroke significantly (OR, 2.99; P = 0.020). A meta-analysis revealed that adult MMD was significantly associated with elevated autoantibodies (OR, 7.663; P = 0.002) and hyperthyroidism (OR, 10.936; P < 0.001). Elevated TPOAb and hyperthyroidism may play important roles in adult MMD with ischemic stroke. Studies focusing on targeted hyperthyroidism and thyroid autoantibodies are necessary in treating adult MMD patients in the future.

Analysis of the clinical characteristics of hemorrhagic moyamoya disease in the Jilin province of northeastern China: A single-center study of 212 cases

The present study aimed to investigate the clinical characteristics of hemorrhagic moyamoya disease (MMD) in Jilin province in northeast China. A total of 212 cases of hemorrhagic MMD were consecutively enrolled from the First Hospital of Jilin University in Changchun, China between January 2011 and January 2015. The patients' general clinical data, including age and gender characteristics, history of previous illnesses, hemorrhage type and onset symptoms, Hunt-Hess classification at admission, imaging characteristics, association with aneurysms, treatments and prognosis, were recorded and analyzed using SPSS 19.0. The results demonstrated that i) patients with hemorrhagic MMD in Jilin province were 47.7±11.5 years of age; ii) hemorrhagic MMD was primarily characterized by subarachnoid hemorrhage; iii) a total of 51.9% of the hemorrhagic MMD cases involved a unilateral artery; iv) a total of 24.1% of the hemorrhagic MMD cases were accompanied by anterior choroid artery and/or posterior communicating artery expansion; and v) following conservative or surgical treatment, patients with a prognostic Glasgow Outcome Scale score of 5 accounted for 65.6% of the study population. Therefore, the present study identified characteristics of MMD in Jilin province in northeast China. These results may improve understanding of the epidemiology of MMD in China, which at present remains not well established. Although the results are representative only of Jilin province in China, the study demonstrated high consistency with other studies, and thus may indirectly contribute to general understanding of hemorrhagic MMD etiology.

The Role of RNF213 4810G>A and 4950G>A Variants in Patients with Moyamoya Disease in Korea

Although a founder variant of RNF213 4810G>A is a major genetic risk factor for moyamoya disease (MMD) in East Asians, the frequency and disease susceptibility of RNF213 variants remain largely unknown. This study investigated the mutation analysis of RNF213 (4448, 4810, 4863, and 4950) between Korean MMD and healthy controls. We performed a polymerase chain reaction-restriction fragment length polymorphism analysis. To identify the association between RNF213 gene polymorphisms and MMD disease, we performed statistical analyses such as multivariable logistic regression and Fisher’s exact test. Genetic data from 117 MMD patients were analyzed and compared with 253 healthy controls. We assessed and compared single nucleotide polymorphisms of RNF213 (4448, 4810, 4863, and 4950) between MMD and control groups. We performed genome-wide association studies to investigate the genetic pathophysiology of MMD. Among the RNF213 variants (4448G>A, 4810G>A, 4863G>A, and 4950G>A), RNF213 4810G>A and 4950G>A variants were more frequent in MMD patients. In a subgroup analysis, the RNF213 4810G>A was more frequent in moyamoya disease, and the comparison with GG+AA genotype was also significantly different in moyamoya patients. These results confirm that RNF213 4810G>A and RNF213 4950G>A were more frequent in MMD patients. We have confirmed that RNF213 4810G>A and 4950G>A are strongly associated with Korean MMD in children and adults as well as for the ischemic and hemorrhagic types.

Combination of Encephalo-Myo-Pial-Synangiosis and Encephalo-Arterio-Pial-Synangiosis Procedure in Pediatric Moya-Moya Disease

Background

Moya-moya disease in children is a cerebrovascular disorder that may cause cerebral ischemic or hemorrhage.

Case Details

We report an 8-year-old boy that was admitted with the chief complaint of repeated sudden half left body paralyze. MRA showed acute thrombotic infarction in the right hemisphere and internal carotid artery stenosis in the form of puffs of smokes. Indirect revascularization surgical procedure with combination of Encephalo-myo-pial-synangiosis (EMS) and Encephalo-arterio-pial-synangiosis (EAS) was performed. It resulted in a good response.

Conclusion

Moya-moya disease can lead to permanent neurological disability if untreated. Satisfactory outcome was noted following combination surgery management with EMS and EAS.

Incidence, Locations, and Longitudinal Course of Cerebral Microbleeds in European Moyamoya

BACKGROUND AND PURPOSE

Cerebral microbleeds (cMBs) have previously been linked with especially high incidence in Asian patients with moyamoya together with high tendency to bleed. This, presumably, is characteristic of patients with moyamoya. Herein, we, therefore, investigate retrospectively the frequency, location, and longitudinal course of cMBs in a large German cohort.

METHODS

We included all patients with moyamoya who underwent standard magnetic resonance imaging, including T2*-weighted images, in our department between 1998 and 2015. Two independent readers evaluated magnetic resonance imaging scans to determine the occurrence of cMBs according to the Brain Observer Microbleed Scale. Demographics, initial symptoms leading to hospitalization, and associated diseases were obtained by chart review.

RESULTS

Overall, there was a total of 242 T2* studies of 101 included moyamoya patients available with a strong female predominance (69.3%). Eight patients (7.9%) were ≤18 years of age. We detected 25 cMBs within 13 patients (12.9%). One patient <18 of age was presented with a cMB; 2 of 3 patients with an intracranial hemorrhage as initial event demonstrated cMB(s). In 72 of 101 cases, there were 1719 person months of follow-up, with 3 adult patients showing 3 de novo cMBs in the course. The majority of cMBs (64.0%) were located at the cortex/gray-white junction.

CONCLUSIONS

Although the frequency of cMBs herein is much higher than the expected age-specific incidence, it is still much lower compared with previous reports on cMBs in moyamoya patients of Asian descent. These results might reflect another ethnic-specific difference in patients diagnosed with moyamoya.

Etiology and pathogenesis of Moyamoya Disease: An update on disease prevalence

Moyamoya disease is a chronic cerebrovascular occlusive disease that is characterized by progressive stenosis of the terminal portion of the internal carotid artery and its main branches. The occurrence of Moyamoya disease is related to immune, genetic, and other factors. Though the research of Moyamoya disease has made great strides in the past 60 years, the etiology and pathogenesis are largely unknown. This review will focus on the genetic pathogenic and inflammation factors of Moyamoya disease.

Genetic susceptibility to cerebrovascular disease

PURPOSE OF REVIEW

Cerebrovascular disease (CeVD) remains a major cause of death and a leading cause of disability worldwide. CeVD is a complex and multifactorial disease caused by the interaction of vascular risk factors, environment, and genetic factors. In the present article, we discussed genetic susceptibility to CeVD, with particular emphasis on genetic studies of the associations between lipid traits and CeVD.

RECENT FINDINGS

Several animal and clinical studies clearly defined genetic predisposition to atherosclerosis and CeVD, and particularly to ischemic stroke. Recent evidence has shown that traditional vascular risk factors explain only a small proportion of variance in atherosclerosis, suggesting that additional nontraditional factors and novel genetic determinants impact CeVD. With the help of genome-wide technology, novel genetic variants have been implicated in CeVD and lipid metabolism such as those in protein convertase subtilisin/kexin type 9 (PCSK9) gene in stroke and familial hypercholesterolemia. These studies are important as they contribute to our understanding of the genetic mechanisms underlying CeVD and to developing more effective CeVD prevention strategies.

SUMMARY

CeVD is a complex and multifactorial disease and genetics likely plays an important role in its pathogenesis. The gene-gene and gene-environment interactions of genes involved in biology of vascular disease, including the lipid metabolism are important factors for individual susceptibility to CeVD. Accounting for individual variation in genes, environment and lifestyle will bring us closer to precision medicine, which is an emerging and recently introduced new approach for disease treatment and prevention in clinical practice.

Sonographic findings associated with stenosis progression and vascular complications in moyamoya disease

OBJECT The progression of arterial stenosis in patients with moyamoya disease (MMD) has variable courses and an unclear mechanism. The authors hypothesized that elevated wall shear stress (WSS) at the terminal internal carotid artery (ICA) and proximal middle cerebral artery (MCA) may facilitate MMD progression. They indirectly evaluated the relative magnitude of WSS (WSS value [WSSV]) with MR angiography (MRA) and transcranial Doppler to determine its predictive value for stenosis progression (SP) and the development of vascular complications. METHODS Thirty-one medically treated patients (58 hemispheres and 95 nonoccluded vessels) were analyzed with serial MRA (median follow-up 23 months). The parameters studied were SP, SP rates (SPRs) for individual ICAs/MCAs, and their mean values from the ipsilateral hemispheres as mean SP (MSP) and MSP rates (MSPRs). Significant progression was defined as decrements of ≥ 20% for SP and MSP and ≥ 10%/year for SPR and MSPR. The development of vascular complications in relevant hemispheres was also recorded. The WSSV (dyne/cm(2)) was defined as the shear rate multiplied by blood viscosity. RESULTS After adjusting the initial stenosis degree and MRA stage of MMD, an SP of ≥ 20% and an SPR of ≥ 10%/year were associated with the highest-quartile WSSVs for all individual vessels and for MCAs and ICAs separately. For each hemisphere, an MSP of ≥ 20% and an MSPR of ≥ 10%/year were associated with the highest-quartile mean WSSVs. Furthermore, significant SP was highly correlated with vascular complications, and the highest-quartile mean WSSV was independently associated with vascular complications in relevant hemispheres. CONCLUSIONS An elevated WSSV is an independent predictor for SP and vascular complications in nonoccluded MMD.

Decompressive hemicraniectomy in the management of acute stroke in children with Moyamoya disease: the difficult balance between the spontaneous postoperative revascularization process and the need for cranial reconstruction

BACKGROUND AND IMPORTANCE

The decompressive hemicraniectomy (DCH) after malignant middle cerebral artery infarction in children is a rare procedure, and the indication is discussed as being controversial. Etiological Moyamoya disease has some additional challenges concerning the therapeutic strategy that have not mentioned in the recent literature, as it is dependent on special pathophysiology.

CLINICAL PRESENTATION

We report a case of a four-year-old patient with a decompressive hemicraniectomy after malignant middle cerebral artery infarction on the right hemisphere based on a Moyamoya syndrome with proximal MCA occlusions on both sides. After the decompression there was a good restitution of the hemiparesis, aphasia, and consciousness loss on admission. The bone flap replacement is usually done after three month in our department to ensure brain swelling has subsided. In this patient the cranioplasty was not arranged because of the development of collateral vessels to the right motor region through the craniotomy defect, to protect the supply of the eloquent cortex.

CONCLUSION

We conclude that the indication of DCH and postoperative treatment should be discussed individually, especially when neovascularisation developments can occur like in Moyamoya disease. An important point is the right timing for bone flap replacement, which should be directly after cerebral edema has subsided prior to the evolution of collaterals through the craniotomy defect. Additionally, leaving the opportunity for neovascularization through smaller defects has to be taken into account.

Moyamoya angiopathy - Is there a Western phenotype?

Moyamoya disease (MMD) is a chronic cerebrovascular disease involving progressive bilateral stenosis of the intracranial segments of the internal carotid arteries. It results in the development of a rich, but friable collateral supply, prone to rupture. The disease is well described in Japanese literature and was originally thought to be a predozminantly Eastern disease. However, the recent literature describes a Western phenotype that may present with a different clinical course. This review aims to describe the variations in the epidemiology of the MMD between Eastern and Western populations, the possible reasons for them and highlight their implications for clinical practise and future research.

Vessel Wall Imaging of the Intracranial and Cervical Carotid Arteries

Vessel wall imaging can depict the morphologies of atherosclerotic plaques, arterial walls, and surrounding structures in the intracranial and cervical carotid arteries beyond the simple luminal changes that can be observed with traditional luminal evaluation. Differentiating vulnerable from stable plaques and characterizing atherosclerotic plaques are vital parts of the early diagnosis, prevention, and treatment of stroke and the neurological adverse effects of atherosclerosis. Various techniques for vessel wall imaging have been developed and introduced to differentiate and analyze atherosclerotic plaques in the cervical carotid artery. High-resolution magnetic resonance imaging (HR-MRI) is the most important and popular vessel wall imaging technique for directly evaluating the vascular wall and intracranial artery disease. Intracranial artery atherosclerosis, dissection, moyamoya disease, vasculitis, and reversible cerebral vasoconstriction syndrome can also be diagnosed and differentiated by using HR-MRI. Here, we review the radiologic features of intracranial artery disease and cervical carotid artery atherosclerosis on HR-MRI and various other vessel wall imaging techniques (e.g., ultrasound, computed tomography, magnetic resonance, and positron emission tomography-computed tomography).

Single Nucleotide Polymorphism in Patients with Moyamoya Disease

Moyamoya disease (MMD) is a chronic, progressive, cerebrovascular occlusive disorder that displays various clinical features and results in cerebral infarct or hemorrhagic stroke. Specific genes associated with the disease have not yet been identified, making identification of at-risk patients difficult before clinical manifestation. Familial MMD is not uncommon, with as many as 15% of MMD patients having a family history of the disease, suggesting a genetic etiology. Studies of single nucleotide polymorphisms (SNPs) in MMD have mostly focused on mechanical stress on vessels, endothelium, and the relationship to atherosclerosis. In this review, we discuss SNPs studies targeting the genetic etiology of MMD. Genetic analyses in familial MMD and genome-wide association studies represent promising strategies for elucidating the pathophysiology of this condition. This review also discusses future research directions, not only to offer new insights into the origin of MMD, but also to enhance our understanding of the genetic aspects of MMD. There have been several SNP studies of MMD. Current SNP studies suggest a genetic contribution to MMD, but further reliable and replicable data are needed. A large cohort or family-based design would be important. Modern SNP studies of MMD depend on novel genetic, experimental, and database methods that will hopefully hasten the arrival of a consensus conclusion.

Mutation genotypes of RNF213 gene from moyamoya patients in Taiwan

Moyamoya disease (MMD) is a disorder characterized by stenosis of bilateral internal carotid arteries with compensatory angiogenesis of the perforating blood vessels. Familial transmission in MMD is common. Recently, mutations in human RNF213 and ACTA2 genes were identified to be responsible for MMD. The present study was to determine whether Taiwanese MMD patients carried mutations in these two genes. Of the 36 MMD patients, eleven was found to have RNF213 mutations. Direct genetic sequencing identified four different RNF213 mutations in the 11 patients from 8 families: five with a p.R4810K, one with p.A1622V, one with p.V3933M, and the other one with p.R4131C. The latter three represent novel missense mutations. No mutation in ACTA2 gene was identified. Clinically, cerebral infarction was common in patients with an RNF213 mutation (9/11). In addition, four mutant patients had developmental delay (4/11) and two had mental dysfunction (2/11). The magnetic resonance angiography of asymptomatic mutant carriers demonstrated high incidence of multiple stenosis of intracranial vessels (3/6, 50%). Since 30.6% (11/36) of Taiwanese moyamoya patients carry an RNF213 mutation and intracranial arterial stenosis was found in half of the asymptomatic mutant carriers, it is suggested that the RNF213 mutation should form part of the diagnostic workup for MMD in clinical practice.

Coronary heart disease in moyamoya disease: are they concomitant or coincidence?

The purpose of this study was to determine the prevalence and characteristics of symptomatic coronary heart disease (CHD) in patients with moyamoya disease (MMD). This retrospective study evaluated 456 patients who received examination for MMD between 1995 and 2012. We reviewed the patients' medical history and coronary imaging, including conventional coronary angiography and coronary computed tomography angiogram (CTA). Among 456 patients with MMD, 21 (4.6%) patients were found to have symptomatic CHD. Ten patients were treated with coronary artery bypass graft or percutaneous coronary intervention for unstable angina or myocardial infarction. Eleven were treated with medication for stable angina (n = 6) and variant angina with mild degree of stenosis (n = 5).The median age of these patients was 44 yr (range, 27-59). The median Framingham score at diagnosing MMD was < 1% (range, < 1%-16%). The old age was associated with CHD in uni- and multivariate analyses (P = 0.021, OR, 1.053; 95% CI, 1.008-1.110). Considering low age of onset and low stroke risk factor, CHD might be a systemic manifestation that is clinically relevant to MMD.

Collaterals: Implications in cerebral ischemic diseases and therapeutic interventions

Despite the tremendous progress made in the treatment of cerebrovascular occlusive diseases, many patients suffering from ischemic brain injury still experience dismal outcomes. Although rehabilitation contributes to post-stroke functional recovery, there is no doubt that interventions that promote the restoration of blood supply are proven to minimize ischemic injury and improve recovery. In response to the acutely decreased blood perfusion during arterial occlusion, arteriogenesis, the compensation of blood flow through the collateral circulation during arterial obstructive diseases can act not only in a timely fashion but also much more efficiently compared to angiogenesis, the sprouting of new capillaries, and a mechanism occurring in a delayed fashion while increases the total resistance of the vascular bed of the affected territory. Interestingly, despite the vast differences between the two vascular remodeling mechanisms, some crucial growth factors and cytokines involved in angiogenesis are also required for arteriogenesis. Understanding the mechanisms underlying vascular remodeling after ischemic brain injury is a critical step towards the development of effective therapies for ischemic stroke. The present article will discuss our current views in vascular remodeling acutely after brain ischemia, namely arteriogenesis, and some relevant clinical therapies available on the horizon in augmenting collateral flow that hold promise in treating ischemic brain injury. This article is part of a Special Issue entitled SI: Cell Interactions In Stroke.

Moyamoya disease and syndromes: from genetics to clinical management

Moyamoya angiopathy is characterized by a progressive stenosis of the terminal portion of the internal carotid arteries and the development of a network of abnormal collateral vessels. This chronic cerebral angiopathy is observed in children and adults. It mainly leads to brain ischemic events in children, and to ischemic and hemorrhagic events in adults. This is a rare condition, with a marked prevalence gradient between Asian countries and Western countries. Two main nosological entities are identified. On the one hand, moyamoya disease corresponds to isolated moyamoya angiopathy, defined as being “idiopathic” according to the Guidelines of the Research Committee on the Pathology and Treatment of Spontaneous Occlusion of the Circle of Willis. This entity is probably multifactorial and polygenic in most patients. On the other hand, moyamoya syndrome is a moyamoya angiopathy associated with an underlying condition and forms a very heterogeneous group with various clinical presentations, various modes of inheritance, and a variable penetrance of the cerebrovascular phenotype. Diagnostic and evaluation techniques rely on magnetic resonance imaging (MRI), magnetic resonance angiography (MRA) conventional angiography, and cerebral hemodynamics measurements. Revascularization surgery can be indicated, with several techniques. Characteristics of genetic moyamoya syndromes are presented, with a focus on recently reported mutations in BRCC3/MTCP1 and GUCY1A3 genes. Identification of the genes involved in moyamoya disease and several monogenic moyamoya syndromes unraveled different pathways involved in the development of this angiopathy. Studying genes and pathways involved in monogenic moyamoya syndromes may help to give insights into pathophysiological models and discover potential candidates for medical treatment strategies.

Clinical features and long-term outcomes of moyamoya disease: a single-center experience with 528 cases in China

OBJECT

The aim of this study was to describe the baseline clinical features and long-term outcomes of patients with moyamoya disease (MMD) based on a 25-year period at a single center in China.

METHODS

 Data obtained in 528 consecutive patients with MMD treated at the authors' hospital from 1984 to 2010 were reviewed retrospectively. Events of transient ischemic attack, new infarction, and hemorrhage were included. The Kaplan-Meier risk of stroke was calculated.

RESULTS

 The mean (± SD) patient age was 26 ± 13 years (range 2–67 years), and the female/male ratio was 0.9:1. There were 332 cases of ischemia and 196 hemorrhages. Adults had a higher rate of bleeding than children (50.7% vs 14.0%, respectively; p < 0.001). One hundred twenty-two patients were treated conservatively, and 406 patients underwent revascularization procedures. Of 528 patients, 331 (62.7%) had at least 1 year of follow-up (median 39.5 months) and data from these patients were analyzed. Rebleeding and mortality rates in patients with hemorrhagic MMD (n = 104) were higher than in those with ischemic MMD (n = 227) (26.9% vs 2.2% [p < 0.001] and 4.8% vs 0.4% [p < 0.05], respectively). Twenty-five of 60 (41.7%) conservatively treated patients and 8 of 271 (2.9%) surgically treated patients experienced rebleeding events, a difference that was significant in the Kaplan-Meier curve of rebleeding (p < 0.01). An improvement in perfusion was found in 164 of 224 (73.2%) surgically treated patients 1 month after discharge. However, there was no significant difference in the rate of ischemic events in the surgical and conservative groups (18.8% and 28.3%, respectively; p = 0.09). Among the 104 hemorrhagic cases, rebleeding attacks were observed in 25 patients in the nonsurgical group (n = 60) and 3 patients in the surgical group (n = 44) (41.7% and 6.8%, respectively; OR 9.7 [95% CI 2.7–35.0]; p < 0.01).

CONCLUSIONS

 There was no difference in the sex distribution of Chinese patients with MMD. Patients with hemorrhagic MMD had a much higher rate of rebleeding and poorer prognosis than those with the ischemic type. Surgical revascularization procedures can improve cerebral perfusion and have a positive impact in preventing rebleeding in patients with hemorrhagic MMD.

Enhanced post-ischemic angiogenesis in mice lacking RNF213; a susceptibility gene for moyamoya disease

Moyamoya disease (MMD) is a chronic occlusive cerebrovascular disease with unknown etiology that is characterized by the development of abnormal vascular networks at the base of the brain. Recent genome-wide studies identified RNF213 as an important MMD susceptibility gene. However, the exact mechanism by which the RNF213 abnormality leads to MMD remains unknown. Thus, we sought to clarify the role of RNF213 in angiogenesis under ischemic conditions using conventional RNF213 knockout mice. We assessed the infarction volume, cerebral edema, and vascular density in the ischemic brain after transient middle cerebral artery occlusion (tMCAO). To further evaluate systemic angiogenesis following chronic ischemia, we investigated blood flow recovery using laser speckle flowmetry, the severity of ambulatory impairments, and vascular density in the hind-limb after permanent femoral artery ligation. Results were compared between homozygous RNF213 knockout mice (RNF213 -/-) and wild-type littermates (Wt). No significant differences were observed in infarction volume or the formation of edema following tMCAO, or in vascular density 28 days after tMCAO between RNF213 -/- and Wt. Blood flow recovery was significantly improved in RNF213 -/- from 3 to 28 days after femoral artery ligation, and angiogenesis as shown by vascular density in the hind-limb was significantly enhanced in RNF213 -/- at 28 days. The amelioration of ambulatory impairments was also evident in RNF213 -/-. Angiogenesis was enhanced in mice lacking RNF213 after chronic hind-limb ischemia, which suggested the potential role of the RNF213 abnormality in the development of pathological vascular networks in chronic ischemia.