Influence of Inflammatory Disease on the Pathophysiology of Moyamoya Disease and Quasi-moyamoya Disease

Risk Factors for Preoperative Cerebral Infarction in Infants with Moyamoya Disease

There have been few reports on the risk factors for preoperative cerebral infarction in childhood moyamoya disease (MMD) in infants under 4 years. The aim of this retrospective study is to identify clinical and radiological risk factors for preoperative cerebral infarction in infants under 4 years old with MMD, and the optimal timing for EDAS was also considered. We retrospectively analyzed the risk factors for preoperative cerebral infarction, confirmed by magnetic resonance angiography (MRA), in pediatric patients aged ˂4 years who underwent encephaloduroarteriosynangiosis between April 2005 and July 2022. The clinical and radiological outcomes were determined by two independent reviewers. In addition, potential risk factors for preoperative cerebral infarction, including infarctions at diagnosis and while awaiting surgery, were analyzed using a univariate model and multivariate logistic regression to identify independent predictors of preoperative cerebral infarction. A total of 160 hemispheres from 83 patients aged <4 years with MMD were included in this study. The mean age of all surgical hemispheres at diagnosis was 2.17±0.831 years (range 0.380-3.81 years). In the multivariate logistic regression model, we included all variables with P<0.1 in the univariate analysis. The multivariate logistic regression analysis indicated that preoperative MRA grade (odds ratio [OR], 2.05 [95% confidence interval [CI], 1.3-3.25], P=0. 002), and age at diagnosis (OR, 0.61 [95% CI, 0.4-0.92], P=0. 018) were predictive factors of infarction at diagnosis. The analysis further indicated that the onset of infarction (OR, 0.01 [95% CI, 0-0.08], P<0.001), preoperative MRA grade (OR, 1.7 [95% CI, 1.03-2.8], P=0.037), and duration from diagnosis to surgery (Diag-Op) (OR, 1.25 [95% CI, 1.11-1.41], P<0.001) were predictive factors for infarction while awaiting surgery. Moreover, the regression analysis indicated that family history (OR, 8.88 [95% CI, 0.91-86.83], P=0.06), preoperative MRA grade (OR, 8.72 [95% CI, 3.44-22.07], P<0.001), age at diagnosis (OR, 0.36 [95% CI, 0.14-0.91], P=0.031), and Diag-Op (OR, 1.38 [95% CI, 1.14-1.67], P=0.001) were predictive factors for total infarction. Therefore, during the entire treatment process, careful observation, adequate risk factor management, and optimal operation time are required to prevent preoperative cerebral infarction, particularly in pediatric patients with a family history, higher preoperative MRA grade, duration from diagnosis to operation longer than 3.53 months, and aged ˂3 years at diagnosis.

Optical coherence tomography findings in acute myocardial infarction patients with familial moyamoya disease

It has been reported that patients with moyamoya disease have a high prevalence of coronary artery disease. On the other hand, the pathology of coronary artery disease is not fully understood. We were able to evaluate vascular properties using optical coherence tomography in a case of acute myocardial infarction that occurred in a relatively young woman with moyamoya disease. Previous reports using intravascular ultrasound have shown that coronary artery lesions in patients with moyamoya disease are caused by fibrous cell proliferation. Optical coherence tomography of our case showed a fibrous plaque rich in macrophages and a lipidic plaque. We believe that our case may lead to elucidation of the etiology of coronary artery disease in patients with moyamoya disease.

Learning objective

It is known that patients with moyamoya disease develop coronary artery disease at a young age, but the etiology has not been clarified. We used optical coherence tomography to evaluate the intravascular conditions of coronary artery disease patients with moyamoya disease. The lesions of coronary artery disease associated with moyamoya disease were mainly arteriosclerotic lesions rich in inflammation.

SDF-1/CXCR4 axis participants in the pathophysiology of adult patients with moyamoya disease

BACKGROUND

Moyamoya disease (MMD) is characterized by an abundance of moyamoya vessels; however, the precise mechanism driving the spontaneous angiogenesis of these compensatory vessels remains unclear. Previous research has established a link between the stromal cell-derived factor-1 (SDF-1)/ CXC receptor 4 (CXCR4) axis and angiogenesis under hypoxic conditions. Nevertheless, the alterations in this axis within the cerebrospinal fluid, arachnoid membranes and vascular tissue of MMD patients have not been fully investigated.

METHODS

Our study enrolled 66 adult MMD patients and 61 patients with atherosclerotic vascular disease (ACVD). We investigated the SDF-1 concentration in cerebrospinal fluid (CSF) and CXCR4 expression level on the arachnoid membranes and vascular tissue. We utilized enzyme-linked immunosorbent assay and immunohistochemistr. Additionally, we cultured and stimulated human brain microvascular endothelial cells (HBMECs) and smooth muscle cells (SMCs) under oxygen and glucose deprivation (OGD) conditions followed by reoxygenation, to examine any changes in the SDF-1/CXCR4 axis.

RESULTS

The results demonstrated an elevation in the level of SDF-1 in CSF among MMD patients compared to those with ACVD. Moreover, the expression of CXCR4 in arachnoid membranes and vascular tissue showed a similar trend. Furthermore, the content of CXCR4 in HBMECs and SMCs increased with the duration of ischemia and hypoxia. However, it was observed that the expression of CXCR4 decreased at OGD/R 24h compared to OGD 24h. The temporal pattern of SDF-1 expression in HBMECs and SMCs mirrored that of CXCR4 expression.

CONCLUSION

These findings indicate a critical role for the SDF-1/CXCR4 axis in the angiogenesis of moyamoya disease.

Knockdown the moyamoya disease susceptibility gene, RNF213, upregulates the expression of basic fibroblast growth factor and matrix metalloproteinase-9 in bone marrow derived mesenchymal stem cells

Moyamoya disease (MMD) is a chronic, progressive cerebrovascular occlusive disease. Ring finger protein 213 (RNF213) is a susceptibility gene of MMD. Previous studies have shown that the expression levels of angiogenic factors increase in MMD patients, but the relationship between the susceptibility gene RNF213 and these angiogenic mediators is still unclear. The aim of the present study was to investigate the pathogenesis of MMD by examining the effect of RNF213 gene knockdown on the expression of matrix metalloproteinase-9 (MMP-9) and basic fibroblast growth factor (bFGF) in rat bone marrow-derived mesenchymal stem cells (rBMSCs). Firstly, 40 patients with MMD and 40 age-matched normal individuals (as the control group) were enrolled in the present study to detect the levels of MMP-9 and bFGF in serum by ELISA. Secondly, Sprague-Dawley male rat BMSCs were isolated and cultured using the whole bone marrow adhesion method, and subsequent phenotypic analysis was performed by flow cytometry. Alizarin red and oil red O staining methods were used to identify osteogenic and adipogenic differentiation, respectively. Finally, third generation rBMSCs were transfected with lentivirus recombinant plasmid to knockout expression of the RNF213 gene. After successful transfection was confirmed by reverse transcription-quantitative PCR and fluorescence imaging, the expression levels of bFGF and MMP-9 mRNA in rBMSCs and the levels of bFGF and MMP-9 protein in the supernatant of the culture medium were detected on the 7th and 14th days after transfection. There was no significant difference in the relative expression level of bFGF among the three groups on the 7th day. For the relative expression level of MMP-9, there were significant differences on the 7th day and 14th day. In addition, there was no statistically significant difference in the expression of bFGF in the supernatant of the RNF213 shRNA group culture medium, while there was a significant difference in the expression level of MMP-9. The knockdown of the RNF213 gene affects the expression of bFGF and MMP-9. However, further studies are needed to determine how they participate in the pathogenesis of MMD. The findings of the present study provide a theoretical basis for clarifying the pathogenesis and clinical treatment of MMD.

Stroke in Asia

BACKGROUND

There is a significant burden of stroke in Asia. Asia has the largest population in the world in 2023, estimated at 4.7 billion. Approximately 9.5-10.6 million strokes will be anticipated annually in the backdrop of a diverse group of well-developed and less developed countries with large disparities in stroke care resources. In addition, Asian countries are in varying phases of epidemiological transition.

SUMMARY

In this review, we examined recent epidemiological features of ischaemic stroke and intracerebral haemorrhage in Asia with recent developments in hyperacute stroke reperfusion therapy and technical improvements in intracerebral haemorrhage. The article also discussed the spectrum of cerebrovascular diseases in Asia, which include intracranial atherosclerosis, intracerebral haemorrhage, infective aetiologies of stroke, moyamoya disease, vascular dissection, radiation vasculopathy, and cerebral venous thrombosis.

KEY MESSAGES

The review of selected literature and recent updates calls for attention to the different requirements for resources within Asia and highlights the breadth of cerebrovascular diseases still requiring further research and more effective therapies.

High-resolution magnetic resonance vessel wall imaging provides new insights into Moyamoya disease

Moyamoya disease (MMD) is a rare condition that affects the blood vessels of the central nervous system. This cerebrovascular disease is characterized by progressive narrowing and blockage of the internal carotid, middle cerebral, and anterior cerebral arteries, which results in the formation of a compensatory fragile vascular network. Currently, digital subtraction angiography (DSA) is considered the gold standard in diagnosing MMD. However, this diagnostic technique is invasive and may not be suitable for all patients. Hence, non-invasive imaging methods such as computed tomography angiography (CTA) and magnetic resonance angiography (MRA) are often used. However, these methods may have less reliable diagnostic results. Therefore, High-Resolution Magnetic Resonance Vessel Wall Imaging (HR-VWI) has emerged as the most accurate method for observing and analyzing arterial wall structure. It enhances the resolution of arterial walls and enables quantitative and qualitative analysis of plaque, facilitating the identification of atherosclerotic lesions, vascular entrapment, myofibrillar dysplasia, moyamoya vasculopathy, and other related conditions. Consequently, HR-VWI provides a new and more reliable evaluation criterion for diagnosing vascular lesions in patients with Moyamoya disease.

A Rare Case of Cardiac Myxoma With Moyamoya Phenomenon: A Disease or Syndrome?

Moyamoya disease (MMD) is a rare, idiopathic, progressive, obstructive, vasculopathy affecting primarily the terminal portions of the intracerebral internal carotid arteries, typically at the base of the brain. It is more commonly seen in people of East Asian descent. The moyamoya phenomenon refers to the characteristic appearance of the tangle of fine blood vessels, also described as a puff of smoke. Moyamoya syndrome (MMS) refers to the constriction-induced chronic brain ischemia that is believed to cause overexpression of proangiogenic factors, creating a fragile network of collateral capillaries. MMS refers to the moyamoya phenomenon in the presence of other congenital or acquired disorders. Intracerebral hemorrhage is the leading cause of death for MMS patients. Overall, the prognosis is variable. Cardiac myxoma can cause embolization of tumor cells, plaques, and thrombus, and recurrent thromboembolism can lead to chronic brain ischemia, which can lead to the development of collaterals. There have been cases reported where the moyamoya phenomenon resolved following myxoma resection. Here, we present the case of a female who had intraventricular bleeding and was diagnosed with MMD. Eighteen months later, she presented with shortness of breath and was diagnosed with cardiac myxoma with multiple valvular regurgitations. The myxoma was surgically removed.

Circulating immune cell landscape and T-cell abnormalities in patients with moyamoya disease

BACKGROUND

Moyamoya disease (MMD) stands as a prominent cause of stroke among children and adolescents in East Asian populations. Although a growing body of evidence suggests that dysregulated inflammation and autoimmune responses might contribute to the development of MMD, a comprehensive and detailed understanding of the alterations in circulating immune cells associated with MMD remains elusive.

METHODS

In this study, we employed a combination of single-cell RNA sequencing (scRNA-seq), mass cytometry and RNA-sequencing techniques to compare immune cell profiles in peripheral blood samples obtained from patients with MMD and age-matched healthy controls.

RESULTS

Our investigation unveiled immune dysfunction in MMD patients, primarily characterized by perturbations in T-cell (TC) subpopulations, including a reduction in effector TCs and an increase in regulatory TCs (Tregs). Additionally, we observed diminished natural killer cells and dendritic cells alongside heightened B cells and monocytes in MMD patients. Notably, within the MMD group, there was an augmented proportion of fragile Tregs, whereas the stable Treg fraction decreased. MMD was also linked to heightened immune activation, as evidenced by elevated expression levels of HLA-DR and p-STAT3.

CONCLUSIONS

Our findings offer a comprehensive view of the circulating immune cell landscape in MMD patients. Immune dysregulation in patients with MMD was characterized by alterations in T-cell populations, including a decrease in effector T-cells and an increase in regulatory T-cells (Tregs), suggest a potential role for disrupted circulating immunity in the aetiology of MMD.

Multiomics and blood-based biomarkers of moyamoya disease: protocol of Moyamoya Omics Atlas (MOYAOMICS)

BACKGROUND

Moyamoya disease (MMD) is a rare and complex cerebrovascular disorder characterized by the progressive narrowing of the internal carotid arteries and the formation of compensatory collateral vessels. The etiology of MMD remains enigmatic, making diagnosis and management challenging. The MOYAOMICS project was initiated to investigate the molecular underpinnings of MMD and explore potential diagnostic and therapeutic strategies.

METHODS

The MOYAOMICS project employs a multidisciplinary approach, integrating various omics technologies, including genomics, transcriptomics, proteomics, and metabolomics, to comprehensively examine the molecular signatures associated with MMD pathogenesis. Additionally, we will investigate the potential influence of gut microbiota and brain-gut peptides on MMD development, assessing their suitability as targets for therapeutic strategies and dietary interventions. Radiomics, a specialized field in medical imaging, is utilized to analyze neuroimaging data for early detection and characterization of MMD-related brain changes. Deep learning algorithms are employed to differentiate MMD from other conditions, automating the diagnostic process. We also employ single-cellomics and mass cytometry to precisely study cellular heterogeneity in peripheral blood samples from MMD patients.

CONCLUSIONS

The MOYAOMICS project represents a significant step toward comprehending MMD's molecular underpinnings. This multidisciplinary approach has the potential to revolutionize early diagnosis, patient stratification, and the development of targeted therapies for MMD. The identification of blood-based biomarkers and the integration of multiple omics data are critical for improving the clinical management of MMD and enhancing patient outcomes for this complex disease.

Chemical and perfusion markers as predictors of moyamoya disease progression and complication types

To investigate the association between chemical markers (triglyceride, C-reactive protein (CRP), and inflammation markers) and perfusion markers (relative cerebral vascular reserve (rCVR)) with moyamoya disease progression and complication types. A total of 314 patients diagnosed with moyamoya disease were included. Triglyceride and CRP levels were assessed and categorized based on Korean guidelines for dyslipidemia and CDC/AHA guidelines, respectively. Perfusion markers were evaluated using Diamox SPECT. Cox proportional hazard analysis was performed to examine the relationship between these markers and disease progression, as well as complication types (ischemic stroke, hemorrhagic stroke, and rCVR deterioration). Elevated triglyceride levels (≥ 200) were significantly associated with higher likelihood of end-point events (HR: 2.292, CI 1.00-4.979, P = 0.03). Severe decreased rCVR findings on Diamox SPECT were also significantly associated with end-point events (HR: 3.431, CI 1.254-9.389, P = 0.02). Increased CRP levels and white blood cell (WBC) count were significantly associated with moyamoya disease progression. For hemorrhagic stroke, higher triglyceride levels were significantly associated with end-point events (HR: 5.180, CI 1.355-19.801, P = 0.02). For ischemic stroke, severe decreased rCVR findings on Diamox SPECT (HR: 5.939, CI 1.616-21.829, P < 0.01) and increased CRP levels (HR: 1.465, CI 1.009-2.127, P = 0.05) were significantly associated with end-point events. Elevated triglyceride, CRP, and inflammation markers, as well as decreased rCVR, are potential predictors of moyamoya disease progression and complication types. Further research is warranted to understand their role in disease pathophysiology and treatment strategies.

Molecular Biomarkers Affecting Moyamoya Disease

Although the pathogenetic pathway of moyamoya disease (MMD) remains unknown, studies have indicated that variations in the RING finger protein RNF 213 is the strongest susceptible gene of MMD. In addition to the polymorphism of this gene, many circulating angiogenetic factors such as growth factors, vascular progenitor cells, inflammatory and immune mediators, angiogenesis related cytokines, as well as circulating proteins promoting intimal hyperplasia, excessive collateral formation, smooth muscle migration and atypical migration may also play critical roles in producing this disease. Identification of these circulating molecules biomarkers may be used for the early detection of this disease. In this chapter, how the hypothesized pathophysiology of these factors affect MMD and the interactive modulation between them are summarized.

Association between systemic immune-inflammatory markers and the risk of moyamoya disease: a case-control study

Background:Systemic immune-inflammatory markers such as neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), lymphocyte-to-monocyte ratio (LMR) and systemic immune-inflammatory index (SII) are associated with the prognosis of many cardiovascular and neoplastic diseases. Moyamoya disease (MMD) is associated with inflammation, but the relationship between systemic immune-inflammatory markers between MMD is unclear. The aim of our study was to analyse the association between systemic immune-inflammatory markers and the risk of MMD and its subtypes.Methods:We consecutively recruited 360 patients with MMD and 89 healthy control subjects in a case-control study to calculate and analyse the association of systemic immune-inflammatory markers with the risk of MMD and its subtypes.Results:The risk of MMD increased with higher levels of NLR (OR 1.237, 95% CI [1.008, 1.520], p = .042). When NLR and SII were assessed as quartile-spaced subgroups, the third quartile grouping of NLR and SII had a higher risk of MMD than the first quartile grouping (NLR: OR 3.206, 95% CI [1.271, 8.088], p = .014; SII: OR 3.074,95% CI [1.232,7.672], p = .016). When NLR was combined with SII, the highest subgroup had a higher risk of MMD than the lowest subgroup (OR2.643, 95% CI [1.340, 5.212], p = .005). The risk of subtypes also increased with higher levels of NLR and SII. The association between the levels of NLR and SII with the staging of the Suzuki stage follows an inverted U-shape. The highest levels of NLR and SII were found in patients with MMD at Suzuki stages 3-4.Conclusion:The risk of MMD increases with elevated systemic immune-inflammatory markers. This study analysed the association of systemic immune-inflammatory markers with the risk of developing MMD and its subtypes, and identified novel inflammatory markers for MMD.

Angiogenic and inflammatory responses in human induced microglia-like (iMG) cells from patients with Moyamoya disease

Angiogenic factors associated with Moyamoya disease (MMD) are overexpressed in M2 polarized microglia in ischemic stroke, suggesting that microglia may be involved in the pathophysiology of MMD; however, existing approaches are not applicable to explore this hypothesis. Herein we applied blood induced microglial-like (iMG) cells. We recruited 25 adult patients with MMD and 24 healthy volunteers. Patients with MMD were subdivided into progressive (N = 7) or stable (N = 18) group whether novel symptoms or radiographic advancement of Suzuki stage within 1 year was observed or not. We produced 3 types of iMG cells; resting, M1-, and M2-induced cells from monocytes, then RNA sequencing followed by GO and KEGG pathway enrichment analysis and qPCR assay were performed. RNA sequencing of M2-induced iMG cells revealed that 600 genes were significantly upregulated (338) or downregulated (262) in patients with MMD. Inflammation and immune-related factors and angiogenesis-related factors were specifically associated with MMD in GO analysis. qPCR for MMP9, VEGFA, and TGFB1 expression validated these findings. This study is the first to demonstrate that M2 microglia may be involved in the angiogenic process of MMD. The iMG technique provides a promising approach to explore the bioactivity of microglia in cerebrovascular diseases.

The Progression of Pathophysiology of Moyamoya Disease

Moyamoya disease (MMD) is a chronic steno-occlusive cerebrovascular disease that often leads to hemorrhagic and ischemic strokes; however, its etiology remains elusive. Surgical revascularization by either direct or indirect bypass techniques to restore cerebral hypoperfusion is the treatment of choice to date. This review aims to provide an overview of the current advances in the pathophysiology of MMD, including the genetic, angiogenic, and inflammatory factors related to disease progression. These factors may cause MMD-related vascular stenosis and aberrant angiogenesis in complex manners. With a better understanding of the pathophysiology of MMD, nonsurgical approaches that target the pathogenesis of MMD may be able to halt or slow the progression of this disease.

Plasma exosomal microRNAs are non-invasive biomarkers of moyamoya disease: A pilot study

BACKGROUND

As a progressive cerebrovascular disease, Moyamoya Disease (MMD) is a common cause of stroke in children and adults. However, the early biomarkers and pathogenesis of MMD remain poorly understood.

METHODS AND MATERIAL

This study was conducted using plasma exosome samples from MMD patients. Next-generation high-throughput sequencing, real-time quantitative PCR, gene ontology analysis, and Kyoto Encyclopaedia of Genes and Genomes pathway analysis of ideal exosomal miRNAs that could be used as potential biomarkers of MMD were performed. The area under the Receiver Operating Characteristic (ROC) curve was used to evaluate the sensitivity and specificity of biomarkers for predicting events.

RESULTS

Exosomes were successfully isolated and miRNA-sequence analysis yielded 1,002 differentially expressed miRNAs. Functional analysis revealed that they were mainly enriched in axon guidance, regulation of the actin cytoskeleton and the MAPK signaling pathway. Furthermore, 10 miRNAs (miR-1306-5p, miR-196b-5p, miR-19a-3p, miR-22-3p, miR-320b, miR-34a-5p, miR-485-3p, miR-489-3p, miR-501-3p, and miR-487-3p) were found to be associated with the most sensitive and specific pathways for MMD prediction.

CONCLUSIONS

Several plasma secretory miRNAs closely related to the development of MMD have been identified, which can be used as biomarkers of MMD and contribute to differentiating MMD from non-MMD patients before digital subtraction angiography.

Physiological and pathophysiological mechanisms of the molecular and cellular biology of angiogenesis and inflammation in moyamoya angiopathy and related vascular diseases

Rationale

The etiology and pathophysiological mechanisms of moyamoya angiopathy (MMA) remain largely unknown. MMA is a progressive, occlusive cerebrovascular disorder characterized by recurrent ischemic and hemorrhagic strokes; with compensatory formation of an abnormal network of perforating blood vessels that creates a collateral circulation; and by aberrant angiogenesis at the base of the brain. Imbalance of angiogenic and vasculogenic mechanisms has been proposed as a potential cause of MMA. Moyamoya vessels suggest that aberrant angiogenic, arteriogenic, and vasculogenic processes may be involved in the pathophysiology of MMA. Circulating endothelial progenitor cells have been hypothesized to contribute to vascular remodeling in MMA. MMA is associated with increased expression of angiogenic factors and proinflammatory molecules. Systemic inflammation may be related to MMA pathogenesis.

Objective

This literature review describes the molecular mechanisms associated with cerebrovascular dysfunction, aberrant angiogenesis, and inflammation in MMA and related cerebrovascular diseases along with treatment strategies and future research perspectives.

Methods and results

References were identified through a systematic computerized search of the medical literature from January 1, 1983, through July 29, 2022, using the PubMed, EMBASE, BIOSIS Previews, CNKI, ISI web of science, and Medline databases and various combinations of the keywords "moyamoya," "angiogenesis," "anastomotic network," "molecular mechanism," "physiology," "pathophysiology," "pathogenesis," "biomarker," "genetics," "signaling pathway," "blood-brain barrier," "endothelial progenitor cells," "endothelial function," "inflammation," "intracranial hemorrhage," and "stroke." Relevant articles and supplemental basic science articles almost exclusively published in English were included. Review of the reference lists of relevant publications for additional sources resulted in 350 publications which met the study inclusion criteria. Detection of growth factors, chemokines, and cytokines in MMA patients suggests the hypothesis of aberrant angiogenesis being involved in MMA pathogenesis. It remains to be ascertained whether these findings are consequences of MMA or are etiological factors of MMA.

Conclusions

MMA is a heterogeneous disorder, comprising various genotypes and phenotypes, with a complex pathophysiology. Additional research may advance our understanding of the pathophysiology involved in aberrant angiogenesis, arterial stenosis, and the formation of moyamoya collaterals and anastomotic networks. Future research will benefit from researching molecular pathophysiologic mechanisms and the correlation of clinical and basic research results.

Moyamoya Disease and Syndrome in Caucasian Patients

Moyamoya disease is a unique cerebrovascular disease characterized by narrowing of the terminal portion of internal carotid arteries and circle of Willis, with consequent development of a network of collateral vessels in response to brain ischemia. Moyamoya vascular pattern can be idiopathic (Moyamoya disease), is more likely to occur in individuals of Asian ascent and in the pediatric age, or is associated with other diseases (Moyamoya syndrome). We present two cases of stroke in young adults, where workup revealed Moyamoya-type vascular changes. The first case report is of a 42-year-old woman presenting with hemorrhagic stroke, with classic angiographic findings of Moyamoya disease, otherwise asymptomatic. The second case concerns a 36-year-old woman admitted with ischemic stroke; besides the typical angiographic pattern of Moyamoya, the patient was diagnosed with antiphospholipid antibody syndrome and Graves' disease, two conditions known to be associated with this vasculopathy. These case reports illustrate the need to consider this entity in the etiological evaluation of ischemic and hemorrhagic cerebrovascular events, even in Western countries, since management and secondary prevention require specific approaches.

Vessel wall enhancement as a predictor of arterial stenosis progression and poor outcomes in moyamoya disease

OBJECTIVES

This study aimed to determine the association between vessel wall enhancement and progression of arterial stenosis and clinical outcomes in patients with moyamoya (MMD) using high-resolution magnetic resonance (HRMR) vessel wall imaging.

METHODS

Consecutive participants diagnosed with MMD were prospectively recruited and underwent HRMR at baseline and during follow-up, which had an interval period of ≥ 6 months and were clinically followed up for ≤ 24 months to record the occurrence of ischemic stroke. The relationship between vessel wall enhancement and arterial stenosis progression and stroke occurrence was evaluated.

RESULTS

HRMR vessel wall imaging was used to identify 309 stenotic lesions at the internal carotid artery (ICA) in 170 participants (mean age: 37.7 ± 11.3 years old, male: 44.1%). The baseline presence (adjusted odds ratio [aOR] = 3.57, 95% CI = 1.97-6.44, p < 0.001) and progression (aOR = 2.96, 95% CI = 1.29-6.80, p = 0.010) of vessel wall enhancement and middle cerebral artery (MCA) involvement (aOR = 4.98, 95% CI = 1.50-16.52, p = 0.009) were significantly associated with rapid progression of arterial stenosis. Furthermore, vessel wall enhancement (adjusted HR = 3.59, 95% CI = 1.33-9.70, p = 0.011) and rapid progression of arterial stenosis (adjusted HR = 4.52, 95% CI = 1.48-13.81, p = 0.008) were correlated with future stroke occurrence.

CONCLUSION

The baseline presence of vessel wall enhancement was associated with rapid progression of arterial stenosis and increased risk for stroke in MMD patients. Our findings suggest that vessel wall enhancement may serve as a predictor of disease progression and poor outcomes in MMD.

KEY POINTS

• The baseline presence of vessel wall enhancement was significantly associated with the rapid progression of arterial stenosis. • The baseline presence of vessel wall enhancement and rapid progression of arterial stenosis were both correlated with increased risk for future occurrence of stroke. • Our findings suggest that vessel wall enhancement may serve as a predictor of rapid progression of arterial stenosis and poor outcomes in MMD patients.

Circulating Inflammatory Cytokine Associated with Poor Prognosis in Moyamoya Disease: A Prospective Cohort Study

Inflammation is a key factor in the development of moyamoya disease. However, the cytokine distribution in moyamoya disease and its impact on prognosis remain unclear. A total of 204 patients with moyamoya disease were enrolled in this study. The peripheral blood was analyzed for baseline data and cytokines, which included IL-6, IL-1β, IL-2R, IL-8, and TNF-α. Patients with the RNF213 mutation and those without the mutation were compared in terms of their differences in cytokines. A mRS score ≥2 was defined as a poor prognosis, and a mRS score <2 was described as a good prognosis, and differences in cytokines were compared between the two groups. Regression analysis was performed to identify markers affecting prognosis. TNF-α and IL-6 levels were higher in the group without the RNF213 mutation compared to the mutation group. Multivariate stepwise regression analysis indicated that the G3 subgroup of IL-6 and the G4 subgroup of TNF-α were the independent risk factors for adverse prognosis in adults with moyamoya disease (OR 3.678, 95% CI [1.491, 9.074], p = 0.005; OR 2.996, 95% CI [1.180, 7.610], p = 0.021). IL-6 and TNF-α were associated with poor prognosis in adult patients with moyamoya disease.

Clinical value of the systemic immune-inflammation index in moyamoya disease

Background

Moyamoya disease (MMD) is a rare cerebrovascular disorder with unknown etiology. The underlying pathophysiological mechanism of moyamoya disease remains to be elucidated, but recent studies have increasingly highlighted that abnormal immune response may be a potential trigger for MMD. Neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), and systemic immune-inflammation index (SII) are inflammatory markers that can reflect the immune-inflammation state of the disease.

Objective

The purpose of this study was to investigate SII, NLR, and PLR in patients with moyamoya disease.

Methods

A total of 154 patients with moyamoya disease (MMD group) and 321 age- and sex-matched healthy subjects (control group) were included in this retrospective case-control study. Complete blood count parameters were assayed to calculate the SII, NLR, and PLR values.

Results

The SII, NLR, and PLR values in the moyamoya disease group were significantly higher than those in the control group [754 ± 499 vs. 411 ± 205 (P < 0.001), 2.83 ± 1.98 vs. 1.81 ± 0.72 (P < 0.001), and 152 ± 64 vs. 120 ± 42 (P < 0.001), respectively]. The SII in the medium-moyamoya vessels of moyamoya disease was higher than that in the high-moyamoya vessels and low-moyamoya vessels (P = 0.005). Using the receiver operating characteristic (ROC) curve analysis to predict MMD, the highest area under the curve (AUC) was determined for SII (0.76 for SII, 0.69 for NLR, and 0.66 for PLR).

Conclusion

Based on the results of this study, patients with moyamoya disease admitted for inpatient care due to acute or chronic stroke have significantly higher SII, NLR, and PLR when compared to blood samples drawn from completely healthy controls in a non-emergent outpatient setting. While the findings may suggest that inflammation plays a role in moyamoya disease, further studies are warranted to corroborate such an association. In the middle stage of moyamoya disease, there may be a more intense imbalance of immune inflammation. Further studies are needed to determine whether the SII index contributes to the diagnosis or serves as a potential marker of an inflammatory response in patients with moyamoya disease.

Ischemic Stroke with Multiple Cerebral Artery Stenosis in a Patient with an Anaplastic Astrocytoma during Bevacizumab Treatment: A Case Report

It has been reported that bevacizumab, an agent administered as an adjuvant therapy for high-grade gliomas, causes thromboembolic complications. We report a cerebral infarction with newly developed cerebral artery stenosis occurring during treatment with bevacizumab for an anaplastic astrocytoma. A 48-year-old female underwent excision surgery for an anaplastic astrocytoma on the right temporal lobe and received radiation therapy and chemotherapy with temozolomide. Twenty months after the maintenance therapy, treatment with bevacizumab was introduced for tumor recurrence. After the 14th course of bevacizumab at 6 months, 27 months after radiation therapy, the patient began experiencing mild right hemiparesis. Magnetic resonance imaging revealed scattered cerebral infarcts on the left frontal lobe and diffuse cerebral artery stenosis of the bilateral internal carotid artery system both inside and outside the radiation-treated area. Antiplatelet medication was commenced, and there was no recurrence of ischemic stroke. The morphological transition of the cerebral arteries should be carefully monitored via magnetic resonance angiography during post-radiation treatment with bevacizumab.

Data-Independent Acquisition-Based Serum Proteomic Profiling of Adult Moyamoya Disease Patients Reveals the Potential Pathogenesis of Vascular Changes

Moyamoya disease (MMD) is a chronic cerebrovascular disease with unknown etiology. The pathogenesis of vascular changes remains unclear. Ischemic and hemorrhagic adult MMD patients and healthy volunteers were enrolled to collect serum for data-independent acquisition (DIA)-based proteomic analysis and ELISA validation. DIA serum proteomic revealed that apolipoprotein C-I (APOC1), apolipoprotein D (APOD), and apolipoprotein A-IV (APOA4) were decreased. The reductases glutathione S-transferase omega-1 (GSTO1) and peptidyl-prolyl cis-trans isomerase A (PPIA) were upregulated, and ADAMTS-like protein 4 (ADAMTSL4) was downregulated in both ischemic and hemorrhagic MMD. Afamin (AFM) and transforming growth factor-beta-induced protein ig-h3 (TGFBI) increased in ischemic patients but decreased in hemorrhagic patients. Serum ELISA results confirmed that APOA4, APOC1, and APOD were decreased compared to controls. Then, we retrospectively analyzed biochemical indexes of 200 MMD patients. A total of 54 enrolled MMD patients showed decreased total cholesterol (TC) and high-density lipoprotein cholesterol (HDL-c). APOA4, APOC1, and APOD were vital factors in the HDL decrease in MMD patients. Lipoprotein dysfunction in MMD patients is involved in MMD. Intimal thickening by enhanced adhesion, middle layer vascular smooth muscle cell migration, and decreased lipid antioxidant function represented by HDL are potential pathogeneses of vascular changes in MMD.

Presurgical Magnetic Resonance Imaging Indicators of Revascularization Response in Adults With Moyamoya Vasculopathy

BACKGROUND

Moyamoya is a progressive intracranial vasculopathy, primarily affecting distal segments of the internal carotid and middle cerebral arteries. Treatment may comprise angiogenesis-inducing surgical revascularization; however, lack of randomized trials often results in subjective treatment decisions.

HYPOTHESIS

Compensatory presurgical posterior vertebrobasilar artery (VBA) flow-territory reactivity, including greater cerebrovascular reactivity (CVR) and reduced vascular delay time, portends greater neoangiogenic response verified on digital subtraction angiography (DSA) at 1-year follow-up.

STUDY TYPE

Prospective intervention cohort.

SUBJECTS

Thirty-one patients with moyamoya (26 females; age = 45 ± 13 years; 41 revascularized hemispheres).

METHODS

Anatomical MRI, hypercapnic CVR MRI, and DSA acquired presurgically in adult moyamoya participants scheduled for clinically indicated surgical revascularization. One-year postsurgery, DSA was repeated to evaluate collateralization.

FIELD STRENGTH

3 T.

SEQUENCE

Hypercapnic T 2 * -weighted gradient-echo blood-oxygenation-level-dependent, T2 -weighted turbo-spin-echo fluid-attenuated-inversion-recovery, T1 -weighted magnetization-prepared-rapid-gradient-echo, and T2 -weighted diffusion-weighted-imaging.

ASSESSMENT

Presurgical maximum CVR and response times were evaluated in VBA flow-territories. Revascularization success was determined using an ordinal scoring system of neoangiogenic collateralization from postsurgical DSA by two cerebrovascular neurosurgeons (R.V.C. with 8 years of experience; M.R.F. with 9 years of experience) and one neuroradiologist (L.T.D. with 8 years of experience). Stroke risk factors (age, sex, race, vasculopathy, and diabetes) were recorded.

STATISTICAL TESTS

Fisher's exact and Wilcoxon rank-sum tests were applied to compare presurgical variables between cohorts with angiographically confirmed good (>1/3 middle cerebral artery [MCA] territory revascularized) vs. poor (<1/3 MCA territory revascularized) outcomes.

SIGNIFICANCE

two-sided P < 0.05. Normalized odds ratios (ORs) were calculated.

RESULTS

Criteria for good collateralization were met in 25 of the 41 revascularized hemispheres. Presurgical normalized VBA flow-territory CVR was significantly higher in those with good (1.12 ± 0.13 unitless) vs. poor (1.04 ± 0.05 unitless) outcomes. Younger (OR = -0.60 ± 0.67) and White (OR = -1.81 ± 1.40) participants had highest revascularization success (good outcomes: age = 42 ± 14 years, race = 84% White; poor outcomes: age = 49 ± 11 years, race = 44% White).

DATA CONCLUSION

Presurgical MRI-measures of VBA flow-territory CVR are highest in moyamoya participants with better angiographic responses to surgical revascularization.

LEVEL OF EVIDENCE

1 TECHNICAL EFFICACY STAGE: 4.

Angioarchitectural Factors Associated with Postoperative Cerebral Infarction in Ischemic Moyamoya Disease

Objective: To investigate the angioarchitectural factors associated with postoperative cerebral infarction in ischemic moyamoya disease. Methods: Data on patients who underwent surgery for ischemic MMD from 1 October 2015 to 31 October 2020, at Peking University International Hospital were collected and retrospectively analyzed. General conditions such as patient sex, age, site of surgery, preoperative manifestations such as TIA attack and old cerebral infarction, and seven angioarchitectural factors of the MMD based on DSA were selected and measured. Statistical analysis was performed by the Pearson chi-square statistic, analysis of variance (ANOVA), and multifactor logistic regression analysis. Results: Age (OR, 0.969; 95%CI, 0.939–1.000; p = 0.049), A1stenosis (OR, 5.843; 95%CI, 1.730–19.732; p = 0.004), M1stenosis (OR, 6.206; 95%CI, 2.079–18.526; p = 0.001), PCA anomalies (OR, 4.367; 95%CI, 1.452–13.129; p = 0.049), Unstable compensation (OR, 5.335; 95%CI, 1.427–19.948; p = 0.013), TIA (OR, 4.264; 95%CI, 1.844–9.863; p = 0.001), Old cerebral infarction (OR, 2.972; 95%CI, 1.194–7.397; p = 0.019). The above seven factors can be used in the regression equation to predict the probability of postoperative cerebral infarction. The prediction accuracy is 90.2%. Conclusions: Age, TIA attack, old cerebral infarction, and five angioarchitectural factors of MMD are strongly associated with postoperative cerebral infarction. Seven factors, including age, TIA attack, old infarction, and four angioarchitectural factors, can be taken to quantify the probability of surgical cerebral infarction in MMD.

Construction of Diagnosis Model of Moyamoya Disease Based on Convolution Neural Network Algorithm

Objective

The convolutional neural network (CNN) was used to improve the accuracy of digital subtraction angiography (DSA) in diagnosing moyamoya disease (MMD), providing a new method for clinical diagnosis of MMD.

Methods

A total of 40 diagnosed with MMD by DSA in the neurosurgery department of our hospital were included. At the same time, 40 age-matched and sex-matched patients were selected as the control group. The 80 included patients were divided into training set (n = 56) and validation set (n = 24). The DSA image was preprocessed, and the CNN was used to extract features from the preprocessed image. The precision and accuracy of the preprocessed image results were evaluated.

Results

There was no significant difference in baseline data between the training set and validation set (P > 0.05). The precision and accuracy of the images before processing were 79.68% and 81.45%, respectively. After image processing, the precision and accuracy of the model are 96.38% and 97.59%, respectively. The area under the curve of the CNN algorithm model was 0.813 (95% CI: 0.718-0.826).

Conclusion

This diagnostic method based on CNN performs well in MMD detection.

Experimental Animal Models for Moyamoya Disease: A Species-Oriented Scoping Review

Moyamoya disease (MMD) is a rare cerebrovascular disease characterized by progressive stenosis of large intracranial arteries and a hazy network of basal collaterals called moyamoya vessels. The etiology and pathogenesis of MMD are still obscure. The biggest obstacles in the basic research of MMD are difficulty in obtaining specimens and the lack of an animal model. It is necessary to use appropriate and rationally designed animal models for the correct evaluation. Several animal models and methods have been developed to produce an effective MMD model, such as zebrafish, mice and rats, rabbits, primates, felines, canines, and peripheral blood cells, each with advantages and disadvantages. There are three mechanisms for developing animal models, including genetic, immunological/inflammatory, and ischemic animal models. This review aims to analyze the characteristics of currently available models, providing an overview of the animal models framework and the convenience of selecting model types for MMD research. It will be a great benefit to identify strategies for future model generations.

Epidemiology of Moyamoya Angiopathy in Eastern India

Introduction

Moyamoya angiopathy (MMA) is a chronic, progressive intracranial vasculopathy with variation in prevalence and clinical manifestations across different populations. This study was aimed to estimate the frequency of MMA as an etiology of stroke and its epidemiological features in the largest cohort of MMA patients in India.

Method

A single-centered cross-sectional observational study over a period of 5 years (2016–2021) was undertaken among consecutive stroke and transient ischemic attack (TIA) patients to look for the presence of MMA angiographically. Each patient with angiographically proven MMA was further evaluated for demographic, clinical, and radiological characteristics.

Results

Among 10,250 consecutive stroke and TIA patients (ischemic = 78%, hemorrhagic = 22%), frequency of MMA was 1.56% (n = 160); 15.3% among children. Female preponderance (Male:Female = 1:1.4) was noted among 160 MMA patients, with bimodal age distribution, first peak at 3–8 years, and a shorter second peak at 41–47 years. Childhood-onset MMA was seen in 75 (46.9%) with commonest initial neurological symptom of fixed-motor-weakness (44.0%), followed by TIA (26.7%); while 85 (53.1%) had adult-onset MMA with fixed-motor-weakness (50.6%) followed by headache (24.7%) as the predominant initial neurological symptom; seizure significantly higher in children (p < 0.001) and headache in adults (p = 0.012). Transient and fixed neurological manifestations constituted 87.5 and 69.4% respectively, of symptoms throughout the disease course. Cerebral infarction (45.0%) and TIA (21.9%) were the commonest types of MMA. On brain imaging, infarction was noted in 80.6%, hemorrhage in 11.3%, significantly higher among adults (p < 0.001). Cortical infarct and Gyral pattern were commoner in children (p = 0.004), subcortical infarcts in adults (p = 0.018). Frequent Suzuki staging observed was stage 4 (31.3%), followed by stage 3 (30.0%). Involvement of posterior circulation was detected in 55.6%, brain atrophy at the time of diagnosis was seen in 65.0%.

Conclusion

MMA is an important etiological consideration in patients with stroke, especially in children. It can present with a myriad of transient neurological symptoms, frequently overlooked, leading to delayed diagnosis, and contributing to socio-economic burden. Indian MMA showed aberrations in its gender predisposition, age distribution, frequency of familial cases, disease manifestation, and type of stroke, in comparison to its Japanese and Caucasian counterparts pointing to the inter- and intra-continent differences of MMA phenotype. Future development of the Indian MMA national registry is of essence.

Covid-19 vaccine (covishield) heralding Moyamoya angiopathy

Indroduction

Thrombotic complications leading to cerebrovascular events occuring in conjunction with Covid-19 vaccination though rare, is well-documented. Moyamoya Angiopathy is a progressive intracranial vasculopathy leading to recurrent strokes.

Case presentation

We present two index cases of young patient presenting with stroke and TIA following Covid-19 vaccination (COVISHIELD) leading to unmasking of Moyamoya Angiopathy.

Conclusion

Arterial stroke following Covid-19 vaccination is documented, but uncommon. However, in the background of a vasculopathy, it may not be so rare. Moyamoya Angiopathy has been closely studied in the model of inflammatory pathophysiology in genetically predisposed patients leading to progressive vaso-occlusive disease. Few reports of Covid-19 infection potentiating Moyamoya Angiopathy symptoms are also documented. Thus, as an extrapolation of the inflammatory etiopathogenesis of Moyamoya Angiopathy, Covid-19 vaccination can similarly affect the Moyamoya symptomatology. These two index cases open new lines of enquiry regarding the interplay of Covid-19 vaccination and neurological destabilization in patients with underlying vasculopathy of inflammatory pathophysiology.

Impact of COVID-19 pandemic in natural course of Moyamoya Angiopathy: an experience from tertiary-care-center in India

Background

COVID-19 mediated immune dysregulation and cytokine storm can precipitate and aggravate Moyamoya angiopathy (MMA), influencing its disease course. This index study was undertaken to prospectively evaluate the status of neurological symptoms of MMA in relation to COVID-19 affection.

Methodology and results

Follow-up MMA patients of institute’s Stroke-clinic were telephonically interview from 24th March to 30th September, 2020. The first call familiarized them with COVID-19 symptoms and neurological manifestations of MMA, followed by monthly-calls with predesigned questionnaire. Patients with suggestion of COVID-19 underwent nasopharyngeal-swab-testing for COVID-19 Reverse transcription-polymerase chain reaction (RT-PCR) positive cases were subjected to antibody levels for COVID-19 Enzyme-linked immunoassay (ELISA) 8–12 weeks after recovery. During symptomatic phase till 14 days of asymptomatic, they were contacted daily/alternate day. Any new onset/worsening of neurological symptoms were noted. The baseline clinico-radiological details were obtained from stroke-clinic registery. Subsequently, all data were analyzed and compared using descriptive statistics. Seventy four of 104 MMA patients could be contacted and enrolled. The mean age, time since last follow-up and compliance to previously prescribed medication were 23.5 ± 16.1 years, 9.2 ± 1.7 months and 90.5% (n = 67), respectively. Aggravation/new onset neurological symptom were seen in 64.3% (n = 9) of COVID-19 positive MMA (n = 14), of which 8 were seen among the 11 pediatric COVID-19 positive MMA [(Transient ischemic attacks) TIA-4, TIA with headache-1, seizure-2, stroke causing mortality-1].

Conclusion

COVID-19 infection can potentiate MMA causing significant morbidity and mortality, especially in children. Providing optimal care for severe diseases (such as MMA) in developing countries during pandemic remains a challenge.

Plasma Lipid Profiling Contributes to Untangle the Complexity of Moyamoya Arteriopathy

Moyamoya arteriopathy (MA) is a rare cerebrovascular disorder characterized by ischemic/hemorrhagic strokes. The pathophysiology is unknown. A deregulation of vasculogenic/angiogenic/inflammatory pathways has been hypothesized as a possible pathophysiological mechanism. Since lipids are implicated in modulating neo-vascularization/angiogenesis and inflammation, their deregulation is potentially involved in MA. Our aim is to evaluate angiogenic/vasculogenic/inflammatory proteins and lipid profile in plasma of MA patients and control subjects (healthy donors HD or subjects with atherosclerotic cerebrovascular disease ACVD). Angiogenic and inflammatory protein levels were measured by ELISA and a complete lipidomic analysis was performed on plasma by mass spectrometry. ELISA showed a significant decrease for MMP-9 released in plasma of MA. The untargeted lipidomic analysis showed a cumulative depletion of lipid asset in plasma of MA as compared to HD. Specifically, a decrease in membrane complex glycosphingolipids peripherally circulating in MA plasma with respect to HD was observed, likely suggestive of cerebral cellular recruitment. The quantitative targeted approach demonstrated an increase in free sphingoid bases, likely associated with a deregulated angiogenesis. Our findings indicate that lipid signature could play a central role in MA and that a detailed biomarker profile may contribute to untangle the complex, and still obscure, pathogenesis of MA.

Platelet-to-Lymphocyte Ratio and Neutrophil-to-Lymphocyte Ratio in Patients With Newly Diagnosed Moyamoya Disease: A Cross-Sectional Study

Inflammation has been proven to be one of the key factors in the pathogenesis of moyamoya disease (MMD). Platelet-to-lymphocyte ratio (PLR) and neutrophil-to-lymphocyte ratio (NLR) are cheap and reliable biomarkers of inflammation. Nevertheless, evidence regarding the relationship among PLR and NLR in patients with MMD is limited. The focus of this subject was to explore the relationship between PLR and NLR in patients with newly diagnosed MMD.

Patients and methods: A cross-sectional study was performed including 261 patients with diagnosed MMD for the first time who were enrolled from our hospital, from 24 March 2013 to 24 December 2018. The clinical characteristics were collected for each patient. Univariate analysis, smooth curve fitting and multivariate piecewise linear regression were showed.

Results: The mean levels or median values (interquartile range) of PLR and NLR were 146.979 ± 51.203 and 2.241 (1.589–2.984), respectively. A significant positive correlation between PLR and NLR levels (P < 0.001) was showed by the univariate analysis. Furthermore, a non-linear relationship was detected between PLR and NLR by smooth curve fitting after adjusting for potential confounders. A multivariate piecewise linear regression model revealed a significant positive correlation between PLR and NLR when the PLR level was lower than 219.82 (β 0.012, 95% CI 0.005, 0.019; P = 0.001). PLR was also significantly positively associated with NLR when PLR concentrations were >219.82 (β 0.098, 95% CI 0.069, 0.128; P < 0.001).

Conclusion: There seemed to be a positive association between PLR and NLR in patients with MMD. This may help to further explain the role of inflammation in the occurrence and progress of MMD.

Quantitative Optical Coherence Tomography Angiography in Patients with Moyamoya Vasculopathy: A Pilot Study

Moyamoya (MM) disease is a chronic cerebrovascular disease that can lead to progressive stenosis of the terminal portions of the internal carotid arteries and their proximal branches. We sought to investigate and quantify retinal vascular changes in patients with MM vasculopathy (MMV) using optical coherence tomography angiography (OCTA) compared to healthy controls. Our findings reveal retinal microvascular changes in patients with MMV and highlights the potential of OCTA imaging for the detection of subclinical retinal pathology.

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.

Changes in Vessel Wall Enhancement Related to the Recent Neurological Symptoms in Patients with Moyamoya Disease

Moyamoya disease (MMD) causes intracranial arterial stenosis progression. The progression of intracranial arterial stenosis will increase the risk of ischemic cerebrovascular events. This study aims to investigate the relationship between intracranial arterial stenosis progression, vessel wall enhancement (VWE), and the recent neurological symptoms. A total of 39 MMD patients (12 male; 37.6 ± 18.0 years old) were registered in this study analysis between April 2016 and July 2018. All patients received MRI at registration and 6, 12, and 24 months post-registration. The incidence of ischemic cerebrovascular events (transit ischemic attacks or cerebral infarction) was checked until December 2018. We evaluated the relationship between the intensity of VWE, intracranial arterial stenosis, and the recent neurological symptoms. During the mean follow-up period of 13.8 ± 5.5 months, the changes in VWE were observed in 33 hemispheres (42.3%), stenosis progression was observed in 21 hemispheres (26.9%), and recent neurological symptoms occurred in 10 hemispheres (12.8%). Stenosis progression was observed in 11 hemispheres (33.3%) in the VWE(+) group and ten hemispheres (22.2%) in the VWE(-) group (p = 0.310). The recent neurological symptoms were observed in eight hemispheres (21.2%) in the VWE(+) group and two hemispheres (4.44%) in the VWE(-) group (odds ratio 6.88, 95% confidence interval 1.35-34.98, p = 0.015). The intensity of VWE sometimes changes. The changes in VWE were significantly associated with the recent neurological symptoms but not with stenosis progression.

The mechanobiological theory: a unifying hypothesis on the pathogenesis of moyamoya disease based on a systematic review

OBJECTIVE

Moyamoya angiopathy (MMA) affects the distal internal carotid artery and is designated as moyamoya disease (MMD) when predisposing conditions are absent, or moyamoya syndrome (MMS) when it occurs secondary to other causes. The authors aimed to investigate the reason for this anatomical site predilection of MMA. There is compelling evidence to suggest that MMA is a phenomenon that occurs due to stereotyped mechanobiological processes. Literature regarding MMD and MMS was systematically reviewed to decipher a common pattern relating to the development of MMA.

METHODS

A systematic review was conducted to understand the pathogenesis of MMA in accordance with PRISMA guidelines. PubMed MEDLINE and Scopus were searched using "moyamoya" and "pathogenesis" as common keywords and specific keywords related to six identified key factors. Additionally, a literature search was performed for MMS using "moyamoya" and "pathogenesis" combined with reported associations. A progressive search of the literature was also performed using the keywords "matrix metalloprotease," "tissue inhibitor of matrix metalloprotease," "endothelial cell," "smooth muscle cell," "cytokines," "endothelin," and "transforming growth factor" to infer the missing links in molecular pathogenesis of MMA. Studies conforming to the inclusion criteria were reviewed.

RESULTS

The literature search yielded 44 published articles on MMD by using keywords classified under the six key factors, namely arterial tortuosity, vascular angles, wall shear stress, molecular factors, blood rheology/viscosity, and blood vessel wall strength, and 477 published articles on MMS associations. Information obtained from 51 articles that matched the inclusion criteria and additional information derived from the progressive search mentioned above were used to connect the key factors to derive a network pattern of pathogenesis.

CONCLUSIONS

Based on the available literature, the authors have proposed a unifying theory for the pathogenesis of MMA. The moyamoya phenomenon appears to be the culmination of an interplay of vascular anatomy, hemodynamics, rheology, blood vessel wall strength, and a plethora of intricately linked mechanobiological molecular mediators that ultimately results in the mechanical process of occlusion of the blood vessel, stimulating angiogenesis and collateral blood supply in an attempt to perfuse the compromised brain.

RNF213 and GUCY1A3 in Moyamoya Disease: Key Regulators of Metabolism, Inflammation, and Vascular Stability

Moyamoya disease is an idiopathic chronically progressive cerebrovascular disease, which causes both ischemic and hemorrhagic stroke. Genetic studies identified RNF213/Mysterin and GUCY1A3 as disease-causing genes. They were also known to be associated with non-moyamoya intracranial large artery disease, coronary artery disease and pulmonary artery hypertension. This review focused on these two molecules and their strong linker, calcineurin/NFAT signaling and caveolin to understand the pathophysiology of moyamoya disease and related vascular diseases. They are important regulators of lipid metabolism especially lipotoxicity, NF-κB mediated inflammation, and nitric oxide-mediated vascular protection. Although intimal thickening with fibrosis and damaged vascular smooth muscle cells are the distinguishing features of moyamoya disease, origin of the fibrous tissue and the mechanism of smooth muscle cell damages remains not fully elucidated. Endothelial cells and smooth muscle cells have long been a focus of interest, but other vascular components such as immune cells and extracellular matrix also need to be investigated in future studies. Molecular research on moyamoya disease would give us a clue to understand the mechanism preserving vascular stability.

Progression in Moyamoya Disease: Clinical Feature, Neuroimaging Evaluation and Treatment

Moyamoya disease (MMD) is a chronic cerebrovascular disease characterized by progressive stenosis of the arteries of the circle of Willis, with the formation of collateral vascular network at the base of the brain. Its clinical manifestations are complicated. Numerous studies have attempted to clarify the clinical features of MMD, including its epidemiology, genetic characteristics, and pathophysiology. With the development of neuroimaging techniques, various neuroimaging modalities with different advantages have deepened the understanding of MMD in terms of structural, functional, spatial, and temporal dimensions. At present, the main treatment for MMD focuses on neurological protection, cerebral blood flow reconstruction, and neurological rehabilitation, such as pharmacological treatment, surgical revascularization, and cognitive rehabilitation. In this review, we discuss recent progress in understanding the clinical features, in the neuroimaging evaluation and treatment of MMD.

The angiographic presentation of European Moyamoya angiopathy

Background and purpose

Little is known about the angiographic presentation of Moyamoya angiopathy (MMA) in non-Asian patients.

Methods

Conventional cerebral angiograms from 155 Caucasian patients diagnosed as MMA were analyzed with respect to extracranial champagne bottle neck sign, Suzuki stages, collateral status, as well as presence of aneurysms and posterior cerebral artery stenosis.

Results

In 84 of 155 angiograms, the extracranial carotid artery was visualized, in 65 of them (77.4%), a champagne bottle neck sign was noted. Of the 278 analyzable hemispheres, 13.7%,11.2%, 37.8%, 27.3%, 8.6%, and 1.4% were classified as Suzuki stage I, stage II, stage III, stage IV, stage V, and stage VI, respectively. Among 280 hemispheres, in 53 hemispheres (18.9%) isolated basal collaterals (pathway I) and in 104 hemispheres (37.1%) choroidal and pericallosal collaterals (including basal collaterals, pathway II) were found. In 74 hemispheres (26.4%) ethmoidal collaterals (pathways III), and in 17 hemispheres (6.1%) vault collaterals were visualized. Patients with higher Suzuki stages IV–VI (p = 0.008) and ethmoidal collaterals (p < 0.001) suffered more often from cerebral hemorrhage. Transient ischemic attacks occurred more frequently in patients with Suzuki stage I to III (p < 0.001). In 10 of 155 patients (6.5%), the angiogram revealed a cerebral aneurysm. In 13 patients (8.4%), a stenotic P1 segment of the posterior cerebral artery was found.

Conclusions

This is so far the largest observational study about angiography in Caucasian European MMA patients. A comparison with Asian data indicates similarity of disease in Caucasian and Asian patients.

Genetic and Proteomic Contributions to the Pathophysiology of Moyamoya Angiopathy and Related Vascular Diseases

Rationale

This literature review describes the pathophysiological mechanisms of the current classes of proteins, cells, genes, and signaling pathways relevant to moyamoya angiopathy (MA), along with future research directions and implementation of current knowledge in clinical practice.

Objective

This article is intended for physicians diagnosing, treating, and researching MA.

Methods and Results

References were identified using a PubMed/Medline systematic computerized search of the medical literature from January 1, 1957, through August 4, 2020, conducted by the authors, using the key words and various combinations of the key words “moyamoya disease,” “moyamoya syndrome,” “biomarker,” “proteome,” “genetics,” “stroke,” “angiogenesis,” “cerebral arteriopathy,” “pathophysiology,” and “etiology.” Relevant articles and supplemental basic science articles published in English were included. Intimal hyperplasia, medial thinning, irregular elastic lamina, and creation of moyamoya vessels are the end pathologies of many distinct molecular and genetic processes. Currently, 8 primary classes of proteins are implicated in the pathophysiology of MA: gene-mutation products, enzymes, growth factors, transcription factors, adhesion molecules, inflammatory/coagulation peptides, immune-related factors, and novel biomarker candidate proteins. We anticipate that this article will need to be updated in 5 years.

Conclusion

It is increasingly apparent that MA encompasses a variety of distinct pathophysiologic conditions. Continued research into biomarkers, genetics, and signaling pathways associated with MA will improve and refine our understanding of moyamoya’s complex pathophysiology. Future efforts will benefit from multicenter studies, family-based analyses, comparative trials, and close collaboration between the clinical setting and laboratory research.

Pathological Circulating Factors in Moyamoya Disease

Moyamoya disease (MMD) is a cerebrovascular disease that presents with vascular stenosis and a hazy network of collateral formations in angiography. However, the detailed pathogenic pathway remains unknown. Studies have indicated that in addition to variations in the of genetic factor RNF213, unusual circulating angiogenetic factors observed in patients with MMD may play a critical role in producing “Moyamoya vessels”. Circulating angiogenetic factors, such as growth factors, vascular progenitor cells, cytokines, inflammatory factors, and other circulating proteins, could promote intimal hyperplasia in vessels and excessive collateral formation with defect structures through endothelial hyperplasia, smooth muscle migration, and atypical neovascularization. This study summarizes the hypothesized pathophysiology of how these circulating factors affect MMD and the interactive modulation between them.

iTRAQ-based Quantitative Proteomic Analysis of Dural Tissues Reveals Upregulated Haptoglobin to be a Potential Biomarker of Moyamoya Disease

Background:

Moyamoya Disease (MMD) is a rare cerebrovascular disease with a high rate of disability and mortality. Immune reactions have been implicated in the pathogenesis of MMD, however, the underlying mechanism is still unclear.

Objective:

To identify proteins related to MMD specially involved in the immunogenesis, we performed a proteomic study.

Methods:

In this work, dural tissues or plasma from 98 patients with MMD, 17 disease controls without MMD, and 12 healthy donors were included. Proteomic profiles of dural tissues from 4 MMD and 4 disease controls were analyzed by an isobaric tag for relative and absolute quantitation (iTRAQ)- based proteomics. The immune-related proteins were explored by bioinformatics and the key MMDrelated proteins were verified by western blot, multiple reaction monitoring methods, enzyme-linked immunosorbent assay, and tissue microarray.

Results:

1,120 proteins were identified, and 82 MMD-related proteins were found with more than 1.5 fold difference compared with those in the control samples. Gene Ontology analysis showed that 29 proteins were immune-related. In particular, Haptoglobin (HP) was up-regulated in dural tissue and plasma of MMD samples compared to the controls, and its up-regulation was found to be sex- and MMD Suzuki grade dependent. Through Receiver Operating Characteristic (ROC) analysis, HP can well discriminate MMD and healthy donors with the Area Under the Curve (AUC) of 0.953.

Conclusion:

We identified the biggest protein database of the dura mater. 29 out of 82 differentially expressed proteins in MMD are involved in the immune process. Of which, HP was up-regulated in dural tissue and plasma of MMD, with sex- and MMD Suzuki grade-dependence. HP might be a potential biomarker of MMD.

Moyamoya angiopathy unmasking systemic lupus erythematosus

A 47-year-old woman with history of seizure disorder (semiology of seizure unknown), not well controlled with antiepileptic drugs since last 30 years presented with 1-year history of intermittent throbbing headache. On the day prior to admission, she experienced worst headache, followed by loss of consciousness. On regaining consciousness, she had neck pain without any focal neurological deficit, but examination was marked by positive meningeal signs. She had history of oral ulceration, photosensitivity and small joints pain for which no medical consultancy was sought until. Following relevant investigations, this case came out to be moyamoya angiopathy secondary to underlying systemic lupus erythematosus. She was put on immunosuppressive and immunomodulator as per recommendations. Among neurological symptoms, headache improved dramatically without any further seizure recurrence till the 6 months of follow-up.

Circulating sortilin levels are associated with inflammation in patients with moyamoya disease

BACKGROUND

Systemic inflammation has been implicated in the pathogenesis of moyamoya disease (MMD). Sortilin is a critical regulator of proinflammatory cytokine secretion in several cell types. The present study investigated the association between circulating sortilin and proinflammatory cytokine levels and the occurrence of MMD.

METHODS

Forty-two MMD cases and 76 age- and sex-matched controls were enrolled in this study between January 2018 and June 2019 at the Affiliated Hospital of Jining Medical University. The demographic and clinical characteristics were evaluated, and the circulating serum and cerebrospinal fluid (CSF) levels of sortilin, sortilin-related receptor with A-type repeats (SorLA), and proinflammatory cytokines including C-reactive protein (CRP), interleukin (IL)-6, interferon (IFN)-γ were measured by enzyme-linked immunosorbent assay. Linear regression and correlation analyses were used to estimate the associations between sortilin, SorLA, and proinflammatory cytokine levels.

RESULTS

MMD patients had higher serum levels of sortilin (P = 0.012), CRP (P = 0.013), IL-6 (P = 0.004), and IFN-γ (P = 0.033) than healthy controls. In MMD patients, serum sortilin was positively correlated with serum proinflammatory cytokines (CRP: r = 0.459, P = 0.0022; IL-6: r = 0.445, P = 0.0032; and IFN-γ: r = 0.448, P = 0.0029) and CSF sortilin (r = 0.440, P = 0.0035); the latter was positively correlated with CSF levels of CRP (r = 0.542, P = 0.0002), IL-6 (r = 0.440, P = 0.0036), and IFN-γ (r = 0.443, P = 0.0033).

CONCLUSIONS

Elevated sortilin level is associated MMD onset and may be a clinically useful biomarker along with proinflammatory cytokine levels.

Trends in hospitalizations and epidemiological characteristics of adults Moyamoya disorder in the United States

BACKGROUND AND PURPOSE

There has been an increasing prevalence of Moyamoya disorder (MMD) reported from recent US literature. There is a paucity of data available regarding trends of prevalence and epidemiological factors in the United States. To goal of this study was to test the hypotheses that racial-, sex-specific MMD hospitalizations and epidemiological factors have been increasing in the United States over the last decade.

METHODS

In this retrospective observational study, using the National Inpatient Sample (NIS) database from 2005 to 2016, MMD-related hospitalizations in patients aged ≥18 years were identified. Trends of epidemiological factors were analyzed over time using the linear regression model with the significance of differences in trend over time assessed using the Wald test. Sex- and race-specific burden of MMD were calculated using the annual US Census data. Joinpoint regression model was used to evaluate trends of hospitalizations over time.

RESULTS

A total of 24,484 adult hospitalizations were identified from January 2005 to September 2015 after excluding <18 years. Among them, approximately ~90% were aged ≤60 years, and 73.5% were females. The most common vascular and non-vascular presentations were ischemic stroke (17.3%) and seizures (21%), respectively. The trend of antithrombotic therapy has increased, while extracranial-intracranial bypass has remained stagnant. The actual average hospitalizations of MMD was 10.4 cases/ million population/year (range 4.1-17.9) and varied significantly by sex (females 14.7 [range 6.2-23.6] and males 5.9 [range 1.8-11.9]) over the 2005 to 2016 study period. The burden of hospitalizations also differed by race (African Americans 40.6 [range 32.8-63.7], Asians 24.8 [15.4-34.8], Non-Hispanic Whites 8.1 [range 6.4-11.5], and Hispanics 8.4 [2.8-12.8]) over the 2010 to 2016 study period. Joinpoint regression analysis showed an increasing overall MMD trend across the study period (+11.7%; P < 0.001), which was higher in males (+14.5% vs. +10.7%; P < 0.001). The Hispanic group had significantly increased hospitalizations over the years (+20.2%; P < 0.001).

CONCLUSION

Although overall more prevalent in females, MMD-related hospitalizations are increasing more rapidly in males. Among the racial subpopulations, African Americans had the highest MMD-related hospitalizations, even higher than Asian Americans. MMD-related hospitalizations have increased quicker in Hispanics than in any other racial group.

Moyamoya Disease: A Review of Current Literature

Moyamoya disease (MMD) is an infrequent disease of cerebral vasculature characterized by long-standing and progressive occlusion of large intracranial arteries. It is seen predominantly in the East Asian population. Most of the cases of MMD are sporadic, but there is a small percentage that is familial. The mode of inheritance is reported to be autosomal dominant with incomplete penetrance. Studies show that the susceptibility gene of MMD is located on chromosome 17. The clinical presentation is variable and is influenced by the age and geographic region of the patient. Children mainly present with ischemia-related neurologic episodes whereas MMD in adults can manifest as either an ischemic event or an intracranial hemorrhage (ICH). The gold standard investigation for diagnosis is cerebral angiography which reveals a smoky appearance of arteries at the base of the skull, thus granting the disease its name. The treatment is mostly surgical and includes direct and indirect revascularization procedures, which prevent the recurrence of both ischemic and hemorrhagic strokes. However, combination revascularization procedures are now on the rise due to studies showing better long-term outcomes. The aim of the article is to critically analyze the current literature and updates on various aspects of MMD including, but not limited to, etiology, diagnosis, and treatment.

An Interesting Case of Moyamoya Disease, a Rare Cause of Transient Ischemic Attacks

Moyamoya disease is a rare, chronic, idiopathic progressive disease characterized by irreversible vascular occlusion of the vessels of the Circle of Willis. The disease was initially considered to be limited to the East Asian population, but now the disease is being reported all over the globe in people of multiple ethnicities. It is crucial that clinicians are aware of the disease and its presentation to prevent under-recognition of the condition. We describe the case of a 44-year-old Caucasian female with a history of hypertension, depression, gastroesophageal reflux disease (GERD), and morbid obesity diagnosed with Moyamoya disease after she presented to the emergency department with recurrent stroke-like symptoms.