Immune response profiling identifies autoantibodies specific to Moyamoya patients

Case Report: A rare presentation of rapidly progressive moyamoya disease refractory to unilateral surgical revascularization

Moyamoya disease (MMD) is a chronic, occlusive cerebrovasculopathy typified by progressive steno-occlusive disease of the intracranial internal carotid arteries (ICAs) and their proximal branches. Moyamoya syndrome (MMS) categorizes patients with characteristic MMD plus associated conditions. As such, the most usual presentations are those that occur with cerebral ischemia, specifically transient ischemic attack, acute ischemic stroke, and seizures. Hemorrhagic stroke, headaches, and migraines can also occur secondary to the compensatory growth of fragile collateral vessels propagated by chronic cerebral ischemia. While the pathophysiology of MMD is unknown, there remain numerous clinical associations including radiation therapy to the brain, inherited genetic syndromes, hematologic disorders, and autoimmune conditions. We describe the case of a 31-year-old woman who presented with recurrent ischemic cerebral infarcts secondary to rapidly progressive, bilateral MMD despite undergoing early unilateral surgical revascularization with direct arterial bypass. She had numerous metabolic conditions and rapidly decompensated, ultimately passing away despite intensive and aggressive interventions. The present case highlights that progression of moyamoya disease to bilateral involvement can occur very rapidly, within a mere 6 weeks, a phenomenon which has not been documented in the literature to our knowledge.

Mass cytometry revealed the circulating immune cell landscape across different Suzuki stages of Moyamoya disease

Moyamoya disease (MMD) is a cerebrovascular disorder marked by progressive arterial narrowing, categorized into six stages known as Suzuki stages based on angiographic features. Growing evidence indicates a pivotal role of systemic immune and inflammatory responses in the initiation and advancement of MMD. This study employs high-dimensional mass cytometry to reveal the immunophenotypic characteristics of peripheral blood immune cells (PBMCs) at various Suzuki stages, offering insights into the progression of MMD. PBMC samples from eight patients with early-stage MMD (Suzuki stages II and III) and eight patients with later-stage MMD (Suzuki stages IV, V, and VI) were analyzed using high-dimensional mass cytometry to evaluate the frequency and phenotype of immune cell subtypes. We identified 15 cell clusters and found that the immunological features of early-stage MMD and later-stage MMD are composed of cluster variations. In this study, we confirmed that, compared to later-stage MMD, the early-stage MMD group exhibits an increase in non-classical monocytes. As the Suzuki stage level increases, the proportions of plasmacytoid DCs and monocyte-derived DCs decrease. Furthermore, T cells, monocytes, DCs, and PMN-MDSCs in the early-stage MMD group show activation of the canonical NF-κB signaling pathway. We summarized and compared the similarities and differences between early-stage MMD patients and later-stage MMD patients. There is a potential role of circulating immune dysfunction and inflammatory responses in the onset and development of MMD.

High Level of Serum Complement C3 Expression is Associated with Postoperative Vasculopathy Progression in Moyamoya Disease

Background

The immune system plays an important role in the onset and development of moyamoya disease (MMD), but the specific mechanisms remain unclear. This study aimed to explore the relationship between the expression of complements and immunoglobulin in serum and progression of MMD.

Methods

A total of 84 patients with MMD and 70 healthy individuals were enrolled. Serum immunoglobulin and complement C3 and C4 expression were compared between healthy individuals and MMD patients. Follow-up was performed at least 6 months post-operation. Univariate and multivariate analysis after adjusting different covariates were performed to explore predictive factors associated with vasculopathy progression. A nomogram basing on the results of multivariate analysis was established to predict vasculopathy progression.

Results

Compared to healthy individuals, MMD patients had significantly lower expression of serum complements C3 (P = 0.003*). Among MMD patients, C3 was significantly lower in those with late-stage disease (P = 0.001*). Of 84 patients, 27/84 (32.1%) patients presented with vasculopathy progression within a median follow-up time of 13.0 months. Age (P=0.006*), diastolic blood pressure (P=0.004*) and serum complement C3 expression (P=0.015*) were associated with vasculopathy progression after adjusting different covariables.

Conclusion

Complement C3 is downregulated in moyamoya disease and decreases even further in late-Suzuki stage disease. Age, diastolic blood pressure and serum complement C3 expression are associated with vasculopathy progression, suggesting that the complement might be involved in the development of moyamoya disease.

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.

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 of thyroid peroxidase antibody with the RNF213 p.R4810K variant in ischemic stroke/transient ischemic attack

BACKGROUND AND AIMS

RNF213 is a susceptibility gene for moyamoya disease and vasospastic angina, with a second hit considered necessary for their development. Elevated thyroid peroxidase antibody (TPO-Ab) levels have been observed in both diseases, suggesting a possible role of TPO-Ab as a second hit for developing RNF213-related vasculopathy. We investigated the association of TPO-Ab levels with RNF213-related ischemic stroke (IS)/transient ischemic attack (TIA), other than moyamoya disease.

METHODS

From the National Cerebral and Cardiovascular Center Genome Registry, a multicenter, prospective, observational study, we enrolled patients with IS/TIA who were admitted within 1 week of onset. Patients with IS/TIA due to definite moyamoya disease or hemorrhagic stroke were excluded. Participants underwent genotyping for RNF213 p. R4810K, and baseline characteristics and TPO-Ab levels were compared between RNF213 p. R4810K variant carriers and non-carriers.

RESULTS

In total, 2090 IS/TIA patients were analyzed [733 women (35.1%); median age 74 (interquartile range, 63-81) years, baseline NIHSS score 3 (2-6)], and 85 (4.1%) of them carried the variant. Median TPO-Ab levels were significantly higher in variant carriers (8.5 IU/mL vs. 2.1 IU/mL, p < 0.01), who also showed a higher frequency of elevated TPO-Ab levels (>16 IU/mL) (27.1% vs. 4.4%). In the multivariate analysis, presence of the RNF213 p. R4810K variant (adjusted odds ratio, 12.42; 95% confidential interval, 6.23-24.75) was significantly associated with elevated TPO-Ab levels.

CONCLUSIONS

Elevated TPO-Ab levels may be significantly associated with presence of the RNF213 p. R4810K variant in IS/TIA patients. Thus, TPO-Ab may inherently modify IS/TIA development in RNF213 p. R4810K variant carriers.

Bioinformatics analysis reveals the landscape of immune cell infiltration and novel immune-related biomarkers in moyamoya disease

Objective: This study aimed to identify immune infiltration characteristics and new immunological diagnostic biomarkers in the cerebrovascular tissue of moyamoya disease (MMD) using bioinformatics analysis. Methods: GSE189993 and GSE141022 were downloaded from the GEO database. Differentially expressed gene and PPI analysis were performed. After performing WGCNA, the most significant module associated with MMD was obtained. Next, functional pathways according to GSEA, GO, and KEGG were enriched for the aforementioned core genes obtained from PPI and WGCNA. Additionally, immune infiltration, using the CIBERSORT deconvolution algorithm, immune-related biomarkers, and the relationship between these genes, was further explored. Finally, diagnostic accuracy was verified with ROC curves in the validation dataset GSE157628. Results: A total of 348 DEGs were screened, including 89 downregulated and 259 upregulated genes. The thistle^l module was detected as the most significant module associated with MMD. Functional analysis of the core genes was chiefly involved in the immune response, immune system process, protein tyrosine kinase activity, secretory granule, and so on. Among 13 immune-related overlapping genes, 4 genes (BTK, FGR, PTPN11, and SYK) were identified as potential diagnostic biomarkers, where PTPN11 showed the highest specificity and sensitivity. Meanwhile, a higher proportion of eosinophils, not T cells or B cells, was demonstrated in the specific immune infiltration landscape of MMD. Conclusion: Immune activities and immune cells were actively involved in the progression of MMD. BTK, FGR, PTPN11, and SYK were identified as potential immune diagnostic biomarkers. These immune-related genes and cells may provide novel insights for immunotherapy in the future.

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.

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.

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.

Identification of immune-infiltrated hub genes as potential biomarkers of Moyamoya disease by bioinformatics analysis

Background

Moyamoya disease (MMD) is a rare chronic progressive cerebrovascular disease. Recent studies have shown that autoimmune inflammation may also be an important pathology in MMD but the molecular mechanisms of inflammation in this disease are still large unknown. This study was designed to identify key biomarkers and the immune infiltration in vessel tissue of MMD using bioinformatics analysis.

Methods

Raw gene expression profiles (GSE157628, GSE141024) were downloaded from the Gene Expression Omnibus (GEO) database, identified differentially expressed genes (DEGs) and performed functional enrichment analysis. The CIBERSORT deconvolution algorithm was used to analyze the proportion of immune cells between MMD and an MMD-negative control group. We screened for neutrophil-associated DEGs, constructed a protein–protein interaction network (PPI) using STRING, and clarified the gene cluster using the Cytoscape plugin MCODE analysis. The receiver operating characteristic (ROC) curve was applied to test and filter the best gene signature.

Results

A total of 570 DEGs were detected, including 212 downregulated and 358 up-regulated genes. Reactome and KEGG enrichment revealed that DEGs were involved in the cell cycle, molecular transport, and metabolic pathways. The immune infiltration profile demonstrated that MMD cerebrovascular tissues contained a higher proportion of neutrophils, monocytes, and natural killer cells in MMD than in controls. The PPI network and MCODE cluster identified nine DEGs (UNC13D, AZU1, PYCARD, ELANE, SDCBP, CCL11, CCL15, CCL20, and CXCL5) associated with neutrophil infiltration. ROC results showed that UNC13D has good specificity and sensitivity (AUC = 0.7846).

Conclusions

The characteristics of immune infiltration in the cerebrovascular tissues of MMD patients and abnormal expression of hub genes provide new insights for understanding MMD progression. UNC13D is shows promise as a candidate molecule to determine neutrophil infiltration characteristics in MMD.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13023-022-02238-4.

Macrohistory of Moyamoya Disease Analyzed Using Artificial Intelligence

INTRODUCTION

Moyamoya disease is characterized by progressive stenotic changes in the terminal segment of the internal carotid artery and the development of abnormal vascular networks called moyamoya vessels. The objective of this review was to provide a holistic view of the epidemiology, etiology, clinical findings, treatment, and pathogenesis of moyamoya disease. A literature search was performed in PubMed using the term "moyamoya disease," for articles published until 2021.

RESULTS

Artificial intelligence (AI) clustering was used to classify the articles into 5 clusters: (1) pathophysiology (23.5%); (2) clinical background (37.3%); (3) imaging (13.2%); (4) treatment (17.3%); and (5) genetics (8.7%). Many articles in the "clinical background" cluster were published from the 1970s. However, in the "treatment" and "genetics" clusters, the articles were published from the 2010s through 2021. In 2011, it was confirmed that a gene called Ringin protein 213 (RNF213) is a susceptibility gene for moyamoya disease. Since then, tremendous progress in genomic, transcriptomic, and epigenetic profiling (e.g., methylation profiling) has resulted in new concepts for classifying moyamoya disease. Our literature survey revealed that the pathogenesis involves aberrations of multiple signaling pathways through genetic mutations and altered gene expression.

CONCLUSION

We analyzed the content vectors in abstracts using AI, and reviewed the pathophysiology, clinical background, radiological features, treatments, and genetic peculiarity of moyamoya disease.

Increased Autoimmunity in Individuals With Down Syndrome and Moyamoya Disease

Objective: To determine if elevated rates of autoimmune disease are present in children with both Down syndrome and moyamoya disease given the high rates of autoimmune disease reported in both conditions and unknown etiology of angiopathy in this population. Methods: A multi-center retrospective case-control study of children with Down syndrome and moyamoya syndrome, idiopathic moyamoya disease, and Down syndrome without cerebrovascular disease was performed. Outcome measures included presence of autoimmune disease, presence of autoantibodies and angiopathy severity data. Comparisons across groups was performed using the Kruskal-Wallis, χ2 and multivariate Poisson regression. Results: The prevalence of autoimmune disease were 57.7, 20.3, and 35.3% in persons with Down syndrome and moyamoya syndrome, idiopathic moyamoya disease, and Down syndrome only groups, respectively (p < 0.001). The prevalence of autoimmune disease among children with Down syndrome and moyamoya syndrome is 3.2 times (p < 0.001, 95% CI: 1.82-5.58) higher than the idiopathic moyamoya group and 1.5 times (p = 0.002, 95% CI: 1.17-1.99) higher than the Down syndrome only group when adjusting for age and sex. The most common autoimmune diseases were thyroid disorders, type I diabetes and Celiac disease. No individuals with idiopathic moyamoya disease had more than one type of autoimmune disorder while 15.4% of individuals with Down syndrome and moyamoya syndrome and 4.8% of individuals with Down syndrome only had >1 disorder (p = 0.05, 95%CI: 1.08-6.08). Interpretation: This study reports elevated rates of autoimmune disease in persons with Down syndrome and moyamoya syndrome providing a nidus for study of the role of autoimmunity in angiopathy in this population.

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.

Association of HLA-DQA2 and HLA-B With Moyamoya Disease in the Chinese Han Population

Objective

An HLA imputation was conducted to explore the relationship between HLA and patients with moyamoya disease (MMD) in the Chinese Han population.

Methods

In this study, we performed an association analysis of the major histocompatibility complex region in 2,786 individuals of Chinese Han ancestry (2,031 controls and 755 patients with MMD), through a widely used HLA imputation method.

Results

We identified that the variant rs3129731 (odds ratio [OR] = 1.79, p = 3.69 × 10⁻¹⁶) located between the MTCO3P1 and HLA-DQA2 is a major genetic risk factor for MMD. In addition to this variant, found in the conditional association analysis, we also detected another independent signal, rs1071817 (OR = 0.62, p = 1.20 × 10⁻¹¹), in HLA-B.

Conclusions

Our research suggests that the genetic polymorphism of HLA-DQA2 and HLA-B could be a genetic predisposing factor for MMD in Chinese Han. This may provide some evidence for further HLA-related studies of patients with MMD of Chinese Han ethnicity and indicates that MMD is an immune-related disease.

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.

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.

Moyamoya: An Update and Review

This article is a clinical review of Moyamoya disease (MMD) and Moyamoya syndrome (MMS). We review the incidence, epidemiology, pathology, historical context, clinical and radiographic findings, diagnostic imaging modalities, radiographic grading systems, the effectiveness of medical, interventional, and surgical treatment, and some of the nuances of surgical treatment options. This article will help pediatricians, neurologists, neurosurgeons, and other clinical practitioners who are involved in caring for patients with this rare clinical entity. MMD is an intrinsic primary disease process that causes bilateral progressive stenosis of the anterior intracranial circulation with the involvement of the proximal portions of the intracranial internal carotid artery (ICA) extending to involve the proximal portions of the anterior cerebral artery (ACA) and middle cerebral artery (MCA); posterior circulation involvement is very rare. This causes a compensatory response where large numbers of smaller vessels such as the lenticulostriate arteries begin to enlarge and proliferate, which gives the angiographic appearance of a "Puff of Smoke", which is translated into Japanese as "Moyamoya". MMS is a secondary process that occurs in response to another underlying pathological process that causes stenosis of intracranial blood vessels, such as radiation. For example, an external source of radiation causes stenosis of the ICA with a compensatory response of smaller blood vessels, which then enlarge and proliferate in response and has the same "Puff of Smoke" appearance on the diagnostic cerebral angiogram (DCA). Histological findings include an irregular internal elastic lamina with luminal narrowing, hyperplasia of the tunica media, and intimal thickening with vacuolar degeneration in smooth muscle cells in the tunica media. Compensation for diminishing blood supply occurs through angiogenesis, which causes the proliferation and enlargement of smaller collateral blood vessels to increase blood supply to under-perfused areas of the brain. MMD is rare in the United States, with just 0.086 newly diagnosed cases per 100,000 individuals per year, which is approximately one per million new cases annually. Risk factors for MMD include Eastern Asian ancestry and predisposing conditions such as neurofibromatosis and Down's syndrome. Clinically, patients often present with stroke signs and symptoms from cerebral ischemia. The proliferation of collateral blood vessels within the basal ganglia can produce movement disorders. Catheter-based DCA is the current gold standard for obtaining a diagnosis. CT perfusion allows preoperative identification of ischemic vascular territories, which may be amenable to surgical intervention. MRI enables rapid detection of acute ischemic stroke using diffusion-weighted Imaging (DWI) and apparent diffusion coefficient (ADC) sequences to assess for any diffusion restriction. Non-contrast CT of the head is used to rule out acute hemorrhage in the presentation of a progressive neurological deficit. The treatment option for Moyamoya is generally surgical; medical treatment has failed to halt disease progression and neuro-interventional techniques such as attempted stenting of stenosed vessels have failed. Surgical options include direct and indirect cerebrovascular bypass.

Moyamoya vasculopathy in a young Caucasian woman with significant methamphetamine use

Background

Moyamoya is a rare cerebrovascular disorder seen predominantly in Asian populations. Methamphetamine use is a recognised cause of stroke in young people, but its pathophysiology is not fully understood. The incidence of moyamoya vasculopathy in methamphetamine-associated stroke is unknown due to a lack of sufficient data. We present a rare case of moyamoya syndrome in a young Caucasian woman with methamphetamine-associated stroke.

Case

A 31-year-old Caucasian woman presented with progressive right arm weakness, speech disturbance and seizures on a background of escalating methamphetamine use in the 9 months prior to admission. She did not have a personal or family history of stroke. MRI revealed both embolic and watershed infarcts in bilateral frontal regions and CT angiography showed development of new lenticulostriate collateral vessels. Digital subtraction angiography confirmed steno-occlusive disease of the bilateral anterior circulations and a ‘puff of smoke’ appearance.

Conclusion

In young patients who present with stroke with unclear aetiology, it is important to obtain a thorough substance use history. Moyamoya vasculopathy should be considered when evaluating the pathophysiology of stroke in young people.

Epidemiology, diagnosis and treatment of moyamoya disease

Moyamoya disease (MMD) is a type of chronic cerebrovascular occlusion disease, which frequently occurs in East Asian populations, including pediatric and adult patients, and may lead to ischemic or hemorrhagic stroke, headache, epilepsy or transient ischemic attack. To date, the underlying mechanisms of MMD have remained to be fully elucidated, but certain studies have indicated that genetic factors may be an important component of its development. Cerebral angiography is the best approach for diagnosing MMD. However, with technological advances, non-invasive techniques are increasingly used to accurately evaluate MMD. MMD is commonly treated via surgery, and an increasing number of patients are benefitting from the intra- and extra-cranial revascularization. The present article provides a comprehensive review of MMD on the basis of previous research.

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.

Moyamoya syndrome causing stroke in young women with type 1 diabetes

CONTEXT

Moyamoya syndrome is an idiopathic brain vasculopathy characterized by stenosis of major intracranial arteries. It often presents in patients with type 1 diabetes or thyroid disease and may have an autoimmune etiology. Moyamoya-related stroke poses a diagnostic challenge as initial symptoms and deficits vary greatly from classic ischemic stroke to encephalopathy, psychiatric, or seizure disorder.

CASE DESCRIPTION

We report 4 patients with type 1 diabetes and other autoimmune diseases who developed moyamoya-related stroke at a young age. Despite having long-term diabetes, these patients exhibited no evidence of dyslipidemia or other typical risk factors for atherosclerosis which might contribute to premature stroke. Three of the four patients underwent revascularization surgery while one patient received conservative management. All patients had improved neurologic function after treatment, some with residual deficits.

CONCLUSION

We highlight the importance of recognizing moyamoya syndrome in patients with pre-existing autoimmune diseases such as type 1 diabetes, as prompt diagnosis and treatment can have major impact on patient outcome and quality of life.

Association between the rs112735431 polymorphism of the RNF213 gene and moyamoya disease: A case-control study and meta-analysis

Ring finger protein 213 (RNF213) gene polymorphisms are thought to be significant in the etiology and pathogenesis of moyamoya disease (MMD). Due to the rarity of MMD patients, their ethnic diversity, and the use of varying methodologies, studies of the association between these polymorphisms and MMD have not been repeatable. This lack of reproducibility affects the strength of the conclusions drawn from their results. We conducted the present case-control study and meta-analysis to provide more precise estimates of the association between the rs112735431 (c.14576G>A) polymorphism and the risk of MMD. A total of 81 MMD patients and 100 healthy controls were enrolled in our case-control study. The RNF213 rs112735431 (c.14576G>A) polymorphism was genotyped using Sanger sequencing after amplification with polymerase chain reaction (PCR). The genetic algorithm (GA) genotype and A allele frequencies of RNF213 rs112735431 (c.14576G>A) (odds ratio, OR=7.10, 95% confidence interval, CI=1.51-33.43, p=0.006; OR=9.37, 95% CI=2.10-41.84, p<0.001, respectively) were significantly higher in the MMD group than those in the control group. In our meta-analysis, we assessed a total of eight case-control studies, including 985 patients and 2335 controls. Pooled ORs indicated a significant association between the presence of the rs112735431 (c.14576G>A) polymorphism and MMD risk (dominant model: OR=74.55, 95% CI=35.86-154.98, p<0.00001). Subgroup analysis based on country and sensitivity analysis verified these results. Our case-control study and meta-analysis both provide evidence of an association between the rs112735431(c.14576G>A) polymorphism in the RNF213 gene and MMD risk.

Haemophilia A and cardiovascular morbidity in a female SHAM syndrome carrier due to skewed X chromosome inactivation

We have recently described a severe haemophilia A and moyamoya (SHAM) syndrome caused by Xq28 deletions encompassing F8 and the BRCC3 familial moyamoya gene. The phenotype includes haemophilia A, moyamoya angiopathy, dysmorphia and hypertension. The genetic analysis of the family of our SHAM patient demonstrated carrier state in proband's mother and sister. The patient's mother is apparently well, whereas his currently 18-years-old sister presents with mild haemophilia A, coarctation of the aorta, hypertension, and ventricular arrhythmia. We performed X chromosome inactivation assay based on HpaII methylation analysis of a polymorphic short tandem repeat (STR) in the X linked AR (androgen receptor) gene and used quantitative real-time RT PCR to measure the expression of genes from the deleted region in proband's family members. We found an extremely skewed X chromosome inactivation pattern in the female members of the family leading to preferential inactivation of the X chromosome without Xq28 deletion in patient's sister. We demonstrated differential expression of the genes from the deleted region in four members of the family, that tightly correlates with the clinical features. In conclusion, we show that the haematologic and cardiovascular morbidity and the discrepancy between patient's sister and mother despite the same genetic lesion are due to skewed X chromosome inactivation leading to clinically relevant differential expression of SHAM syndrome genes. This report highlights the role for BRCC3 in cardiovascular physiology and disease, and demonstrates that in some complex hereditary syndromes full diagnostics may require the examination of both genetic and epigenetic events.

Disease Variant Landscape of a Large Multiethnic Population of Moyamoya Patients by Exome Sequencing

Moyamoya disease (MMD) is a rare disorder characterized by cerebrovascular occlusion and development of hemorrhage-prone collateral vessels. Approximately 10-12% of cases are familial, with a presumed low penetrance autosomal dominant pattern of inheritance. Diagnosis commonly occurs only after clinical presentation. The recent identification of the RNF213 founder mutation (p.R4810K) in the Asian population has made a significant contribution, but the etiology of this disease remains unclear. To further develop the variant landscape of MMD, we performed high-depth whole exome sequencing of 125 unrelated, predominantly nonfamilial, ethnically diverse MMD patients in parallel with 125 internally sequenced, matched controls using the same exome and analysis platform. Three subpopulations were established: Asian, Caucasian, and non-RNF213 founder mutation cases. We provided additional support for the previously observed RNF213 founder mutation (p.R4810K) in Asian cases (P = 6.01×10(-5)) that was enriched among East Asians compared to Southeast Asian and Pacific Islander cases (P = 9.52×10(-4)) and was absent in all Caucasian cases. The most enriched variant in Caucasian (P = 7.93×10(-4)) and non-RNF213 founder mutation (P = 1.51×10(-3)) cases was ZXDC (p.P562L), a gene involved in MHC Class II activation. Collapsing variant methodology ranked OBSCN, a gene involved in myofibrillogenesis, as most enriched in Caucasian (P = 1.07×10(-4)) and non-RNF213 founder mutation cases (P = 5.31×10(-5)). These findings further support the East Asian origins of the RNF213 (p.R4810K) variant and more fully describe the genetic landscape of multiethnic MMD, revealing novel, alternative candidate variants and genes that may be important in MMD etiology and diagnosis.

Elevated Serum MicroRNA Let-7c in Moyamoya Disease

BACKGROUND

Few studies have examined the relationship between mircroRNAs and moyamoya disease (MMD). We performed a study of the significance of let-7c expression in the serum of MMD patients.

METHODS

The experimental group includes 49 MMD patients, and the control group consists of 30 normal people, 20 cerebral hemorrhage patients, 20 massive cerebral infarction patients, 20 nonmassive cerebral infarction patients, and 20 neurological autoimmune disease patients. Let-7 family levels were determined by polymerase chain reaction. A dual luciferase assay was used to test whether let-7c recognized the 3'UTR of RNF213.

RESULTS

The expression level of let-7c in MMD patients is higher than that observed in the control groups (P < .001). The luciferase assay results indicated that hsa-let-7c could diminish luciferase activity from a reporter vector containing the 3'-UTR of RNF213 (P < .05). The suppression of luciferase activity is not found in mutRNF213 (P > .05).

CONCLUSIONS

Increased expression of let-7c in MMD patients may contribute to MMD pathogenesis by targeting RNF213. Thus, let-7c may be a potential biomarker for the diagnosis of MMD.

Endothelial cell antibodies associated with novel targets and increased rejection

The initial contact point between a recipient's immune system and a transplanted graft is the vascular endothelium. Clinical studies suggest a pathogenic role for non-HLA antiendothelial cell antibodies (AECAs) in allograft rejection; however, evidence linking AECAs of known specificity to in vivo vascular injury is lacking. Here, we used high-density protein arrays to identify target antigens for AECAs isolated from the sera of recipients of kidney transplants experiencing antibody-mediated rejection in the absence of donor-specific HLA antibodies. Four antigenic targets expressed on endothelial cells were identified: endoglin, Fms-like tyrosine kinase-3 ligand, EGF-like repeats and discoidin I-like domains 3, and intercellular adhesion molecule 4; the first three have been implicated in endothelial cell activation and leukocyte extravasation. To validate these findings, ELISAs were constructed, and sera from an additional 150 renal recipients were tested. All four AECAs were detected in 24% of pretransplant sera, and they were associated with post-transplant donor-specific HLA antibodies, antibody-mediated rejection, and early transplant glomerulopathy. AECA stimulation of endothelial cell cultures increased adhesion molecule expression and production of inflammatory cytokines: regulated on activation, normal T cell expressed and secreted PDGF and RESISTIN. These correlations between in vitro experiments and in vivo histopathology suggest that AECAs activate the vascular endothelium, amplifying the alloimmune response and increasing microvascular damage. Given the growing number of transplant candidates, a better understanding of the antigenic targets, beyond HLA, and mechanisms of immune injury will be essential for improving long-term allograft survival.

Recent advances in moyamoya disease: pathophysiology and treatment

Moyamoya disease is a progressive intracranial arteriopathy characterized by bilateral stenosis of the distal portion of the internal carotid artery and the proximal anterior and middle cerebral arteries, resulting in transient ischemic attacks or strokes. The pathogenesis of moyamoya disease remains unresolved, but recent advances have suggested exciting new insights into a genetic contribution as well as into other pathophysiological mechanisms. Treatment that may halt progression of the disease or even reverse the intracranial arteriopathy is yet to be found. There are strong indications that neurosurgical intervention, through direct, indirect, or combined revascularization surgery, can reduce the risk of ischemic stroke and possibly also cognitive dysfunction by improving cerebral perfusion, although randomized clinical trials have not been performed. Many questions regarding the indication for and timing of surgery remain unanswered. In this review, we discuss recent developments in the pathogenesis and treatment of moyamoya disease.

Moving beyond HLA: a review of nHLA antibodies in organ transplantation

Given the finite graft life expectancy of HLA identical organ transplants and the recognition of humoral graft injury in the absence of donor directed anti-HLA antibodies, the clinical impact of antibodies against non-HLA (nHLA) antigens in transplant injury is being increasingly recognized. The recognition of the impact of nHLA antigen discrepancies between donor and recipient on transplant outcomes is timely given the advances in rapid and lower cost sequencing methods that can soon provide complete maps of all recipient and donor HLA and nHLA mismatch data. In this review, we present a summary of recent reports evaluating the role of nHLA antibodies and their relevance to the field of organ transplantation.