Cerebrovascular Disease Progression in Patients With ACTA2 Arg179 Pathogenic Variants

Clinical Approach to Genetic Cerebral Arteriopathy in the Adult Patient With Ischemic Stroke

Genetic arteriopathies leading to stroke in adults constitute a diverse group of cerebrovascular disorders with distinct etiologies, pathophysiologic mechanisms, and clinical presentations. As imaging modalities better delineate subtle changes in cerebral vasculature and access to genetic testing increases, the detection rate for these conditions is expected to rise, particularly among young adults with idiopathic cerebral arteriopathy and stroke. Adults with stroke in the setting of a genetic cerebral arteriopathy often present with few traditional stroke risk factors and, in certain cases, have characteristic clinical features, cerebrovascular imaging findings, and often concurrent systemic vasculopathy, such as aortopathy, which are important to recognize. Given that there are over 50 recognized genetic cerebral arteriopathies that can cause ischemic and hemorrhagic stroke in young adults, it can be a significant diagnostic challenge for the practicing neurologist when faced with a genetic cerebral arteriopathy, because clinical algorithms for a systematic approach to genetic cerebral arteriopathies are lacking. In this review, we present a phenotype-driven, clinically oriented algorithm to guide the diagnostic workup when suspecting a genetic cerebral arteriopathy in an adult patient while highlighting the genetic basis of each disease, molecular mechanisms, clinical manifestations, diagnostic approaches, and emerging therapeutic strategies. Moreover, given the lack of widely available gene panels for diagnostic germline testing for genetic cerebral arteriopathies, we propose key genes to be tested and focused on in each clinical scenario, to better decipher the underlying diagnosis in these rare conditions.

Cardiovascular Management of Aortopathy in Children: A Scientific Statement From the American Heart Association

Aortopathy encompasses a spectrum of conditions predisposing to dilation, aneurysm, dissection, or rupture of the aorta and other blood vessels. Aortopathy is diagnosed commonly in children, from infancy through adolescence, primarily affecting the thoracic aorta, with variable involvement of the peripheral vasculature. Pathogeneses include connective tissue disorders, smooth muscle contraction disorders, and congenital heart disease, including bicuspid aortic valve, among others. The American Heart Association has published guidelines for diagnosis and management of thoracic aortic disease. However, these guidelines are predominantly focused on adults and cannot be applied adeptly to growing children with emerging features, growth and developmental changes, including puberty, and different risk profiles compared with adults. Management to reduce risk of progressive aortic dilation and dissection or rupture in children is complex and involves genetic testing, cardiovascular imaging, medical therapy, lifestyle modifications, and surgical guidance that differ in many ways from adult management. Pediatric practice varies widely, likely because aortopathy is pathogenically heterogeneous, including genetic and nongenetic conditions, and there is limited published evidence to guide care in children. To optimize care and reduce variation in management, experts in pediatric aortopathy convened to generate this scientific statement regarding the cardiovascular care of children with aortopathy. Available evidence and expert consensus were combined to create this scientific statement. The most common causes of pediatric aortopathy are reviewed. This document provides a general framework for cardiovascular management of aortopathy in children, while allowing for modification based on the personal and familial characteristics of each child and family.

2022 ACC/AHA guideline for the diagnosis and management of aortic disease: A report of the American Heart Association/American College of Cardiology Joint Committee on Clinical Practice Guidelines

AIM

The "2022 ACC/AHA Guideline for the Diagnosis and Management of Aortic Disease" provides recommendations to guide clinicians in the diagnosis, genetic evaluation and family screening, medical therapy, endovascular and surgical treatment, and long-term surveillance of patients with aortic disease across its multiple clinical presentation subsets (ie, asymptomatic, stable symptomatic, and acute aortic syndromes).

METHODS

A comprehensive literature search was conducted from January 2021 to April 2021, encompassing studies, reviews, and other evidence conducted on human subjects that were published in English from PubMed, EMBASE, the Cochrane Library, CINHL Complete, and other selected databases relevant to this guideline. Additional relevant studies, published through June 2022 during the guideline writing process, were also considered by the writing committee, where appropriate.

STRUCTURE

Recommendations from previously published AHA/ACC guidelines on thoracic aortic disease, peripheral artery disease, and bicuspid aortic valve disease have been updated with new evidence to guide clinicians. In addition, new recommendations addressing comprehensive care for patients with aortic disease have been developed. There is added emphasis on the role of shared decision making, especially in the management of patients with aortic disease both before and during pregnancy. The is also an increased emphasis on the importance of institutional interventional volume and multidisciplinary aortic team expertise in the care of patients with aortic disease.

Augmenting Mitochondrial Respiration in Immature Smooth Muscle Cells with an ACTA2 Pathogenic Variant Mitigates Moyamoya-like Cerebrovascular Disease

ACTA2 pathogenic variants altering arginine 179 cause childhood-onset strokes due to moyamoya disease (MMD)-like occlusion of the distal internal carotid arteries. A smooth muscle cell (SMC)-specific knock-in mouse model (Acta2SMC-R179C/+) inserted the mutation into 67% of aortic SMCs, whereas explanted SMCs were uniformly heterozygous. Acta2R179C/+ SMCs fail to fully differentiate and maintain stem cell-like features, including high glycolytic flux, and increasing oxidative respiration (OXPHOS) with nicotinamide riboside (NR) drives the mutant SMCs to differentiate and decreases migration. Acta2SMC-R179C/+ mice have intraluminal MMD-like occlusive lesions and strokes after carotid artery injury, whereas the similarly treated WT mice have no strokes and patent lumens. Treatment with NR prior to the carotid artery injury attenuates the strokes, MMD-like lumen occlusions, and aberrant vascular remodeling in the Acta2SMC-R179C/+ mice. These data highlight the role of immature SMCs in MMD-associated occlusive disease and demonstrate that altering SMC metabolism to drive quiescence of Acta2R179C/+ SMCs attenuates strokes and aberrant vascular remodeling in the Acta2SMC-R179C/+ mice.

Nuclear Smooth Muscle α-actin Participates in Vascular Smooth Muscle Cell Differentiation

Missense variants throughout ACTA2, encoding smooth muscle α-actin (αSMA), predispose to adult-onset thoracic aortic disease, but variants disrupting arginine 179 (R179) lead to Smooth Muscle Dysfunction Syndrome (SMDS) characterized by diverse childhood-onset vascular diseases. Here we show that αSMA localizes to the nucleus in wildtype (WT) smooth muscle cells (SMCs), enriches in the nucleus with SMC differentiation, and associates with chromatin remodeling complexes and SMC contractile gene promotors. The ACTA2 p.R179 αSMA variant shows decreased nuclear localization. Primary SMCs from Acta2 SMC-R179C/+ mice are less differentiated than WT SMCs in vitro and in vivo and have global changes in chromatin accessibility. Induced pluripotent stem cells from patients with ACTA2 p.R179 variants fail to fully differentiate from neuroectodermal progenitor cells to SMCs, and single-cell transcriptomic analyses of an ACTA2 p.R179H patient's aortic tissue show increased SMC plasticity. Thus, nuclear αSMA participates in SMC differentiation, and loss of this nuclear activity occurs with ACTA2 p.R179 pathogenic variants.

Neonatal diagnosis of ACTA2-related disease: A case report and review of literature

Multisystemic smooth muscle dysfunction syndrome (MSMDS, OMIM # 613834) is a rare autosomal dominant condition caused by pathogenetic variants of ACTA2 gene that result in impaired muscle contraction. MSMDS is characterized by an increased susceptibility to aneurismal dilatations and dissections, patent ductus arteriosus, early onset coronary artery disease, congenital mydriasis, chronic interstitial lung disease, hypoperistalsis, hydrops of gall bladder, and hypotonic bladder. Here, we report an early diagnosis of a MSMDS related to ACTA2 p.Arg179His (R179H) mutation in a newborn and performed a review of the literature. An early diagnosis of MSMDS is extremely important, because of the severe involvement of cardiovascular system in the MSMDS. Multidisciplinary care and surveillance and timely management of symptoms are important to reduce the risk of complications.

Increasing precision in the management of pediatric neurosurgical cerebrovascular diseases with molecular genetics

Recent next-generation DNA and RNA sequencing studies of congenital and pediatric cerebrovascular anomalies such as moyamoya disease, arteriovenous malformations, vein of Galen malformations, and cavernous malformations have shed new insight into the genetic regulation of human cerebrovascular development by implicating multiple novel disease genes and signaling pathways in the pathogenesis of these disorders. These diseases are now beginning to be categorized by molecular disruptions in canonical signaling pathways that impact the differentiation and proliferation of specific venous, capillary, or arterial cells during the hierarchical development of the cerebrovascular system. Here, the authors discuss how the continued study of these and other congenital cerebrovascular conditions has the potential to replace the current antiquated, anatomically based disease classification systems with a molecular taxonomy that has the potential to increase precision in genetic counseling, prognostication, and neurosurgical and endovascular treatment stratification. Importantly, the authors also discuss how molecular genetic data are already informing clinical trials and catalyzing the development of targeted therapies for these conditions historically considered as exclusively neurosurgical lesions.

Cerebral arteriopathy and ischemic stroke in a pediatric MYH11 patient

OBJECTIVES

Mutations in the MYH11 gene result in smooth muscle cell dysfunction and are associated with familial thoracic aortic aneurysms and dissection. We describe a pediatric patient with a stroke and a pathogenic MYH11 IVS32G>A mutation, and a phenotype similar to ACTA2.

METHODS

A proband girl with an acute ischemic stroke underwent genetic analysis and 7T high-resolution MRI.

RESULTS

A 12-year-old girl presented with a right middle cerebral artery occlusion. She received thrombolysis and underwent mechanical thrombectomy. An extensive stroke work-up was negative. A three-generation pedigree showed a splice site mutation of MYH11 IVS32G>A of the proband and three more family members. A 7T-MRI showed "broomstick-like" straightening of distal arterial segments, a V-shaped anterior corpus callosum and a post-stroke cystic area of encephalomalacia. This vascular appearance and parenchymal abnormalities typically present in patients with an ACTA2 phenotype. 7T-MRI also demonstrated thickening of the right middle cerebral arterial wall.

DISCUSSION

This case suggests that MYH11 patients may have a similar angiographic and brain parenchymal phenotype to patients with ACTA2 mutations. This is the first report of arterial wall thickening in a MYH11 stroke patient using 7T-MRI. Patients with MYH11 mutations may display a focal cerebral steno-occlusive arteriopathy that may lead to stroke.

Nuclear Smooth Muscle α-actin in Vascular Smooth Muscle Cell Differentiation

Missense variants throughout ACTA2, encoding smooth muscle α-actin (αSMA), predispose to adult onset thoracic aortic disease, but variants disrupting arginine 179 (R179) lead to Smooth Muscle Dysfunction Syndrome (SMDS) characterized by childhood-onset diverse vascular diseases. Our data indicate that αSMA localizes to the nucleus in wildtype (WT) smooth muscle cells (SMCs), enriches in the nucleus with SMC differentiation, and associates with chromatin remodeling complexes and SMC contractile gene promotors, and the ACTA2 p.R179 variant decreases nuclear localization of αSMA. SMCs explanted from a SMC-specific conditional knockin mouse model, Acta2SMC-R179/+, are less differentiated than WT SMCs, both in vitro and in vivo, and have global changes in chromatin accessibility. Induced pluripotent stem cells from patients with ACTA2 p.R179 variants fail to fully differentiate from neural crest cells to SMCs, and single cell transcriptomic analyses of an ACTA2 p.R179H patient's aortic tissue shows increased SMC plasticity. Thus, nuclear αSMA participates in SMC differentiation and loss of this nuclear activity occurs with ACTA2 p.R179 pathogenic variants.

2022 ACC/AHA Guideline for the Diagnosis and Management of Aortic Disease: A Report of the American Heart Association/American College of Cardiology Joint Committee on Clinical Practice Guidelines

AIM

The "2022 ACC/AHA Guideline for the Diagnosis and Management of Aortic Disease" provides recommendations to guide clinicians in the diagnosis, genetic evaluation and family screening, medical therapy, endovascular and surgical treatment, and long-term surveillance of patients with aortic disease across its multiple clinical presentation subsets (ie, asymptomatic, stable symptomatic, and acute aortic syndromes).

METHODS

A comprehensive literature search was conducted from January 2021 to April 2021, encompassing studies, reviews, and other evidence conducted on human subjects that were published in English from PubMed, EMBASE, the Cochrane Library, CINHL Complete, and other selected databases relevant to this guideline. Additional relevant studies, published through June 2022 during the guideline writing process, were also considered by the writing committee, where appropriate. Structure: Recommendations from previously published AHA/ACC guidelines on thoracic aortic disease, peripheral artery disease, and bicuspid aortic valve disease have been updated with new evidence to guide clinicians. In addition, new recommendations addressing comprehensive care for patients with aortic disease have been developed. There is added emphasis on the role of shared decision making, especially in the management of patients with aortic disease both before and during pregnancy. The is also an increased emphasis on the importance of institutional interventional volume and multidisciplinary aortic team expertise in the care of patients with aortic disease.

2022 ACC/AHA Guideline for the Diagnosis and Management of Aortic Disease: A Report of the American Heart Association/American College of Cardiology Joint Committee on Clinical Practice Guidelines

AIM

The "2022 ACC/AHA Guideline for the Diagnosis and Management of Aortic Disease" provides recommendations to guide clinicians in the diagnosis, genetic evaluation and family screening, medical therapy, endovascular and surgical treatment, and long-term surveillance of patients with aortic disease across its multiple clinical presentation subsets (ie, asymptomatic, stable symptomatic, and acute aortic syndromes).

METHODS

A comprehensive literature search was conducted from January 2021 to April 2021, encompassing studies, reviews, and other evidence conducted on human subjects that were published in English from PubMed, EMBASE, the Cochrane Library, CINHL Complete, and other selected databases relevant to this guideline. Additional relevant studies, published through June 2022 during the guideline writing process, were also considered by the writing committee, where appropriate.

STRUCTURE

Recommendations from previously published AHA/ACC guidelines on thoracic aortic disease, peripheral artery disease, and bicuspid aortic valve disease have been updated with new evidence to guide clinicians. In addition, new recommendations addressing comprehensive care for patients with aortic disease have been developed. There is added emphasis on the role of shared decision making, especially in the management of patients with aortic disease both before and during pregnancy. The is also an increased emphasis on the importance of institutional interventional volume and multidisciplinary aortic team expertise in the care of patients with aortic disease.

The Genetic Landscape of Ischemic Stroke in Children - Current Knowledge and Future Perspectives

Stroke in childhood has multiple etiologies, which are mostly distinct from those in adults. Genetic discoveries over the last decade pointed to monogenic disorders as a rare but significant cause of ischemic stroke in children and young adults, including small vessel and arterial ischemic stroke. These discoveries contributed to the understanding that stroke in children may be a sign of an underlying genetic disease. The identification of these diseases requires a detailed medical and family history collection, a careful clinical evaluation for the detection of systemic symptoms and signs, and neuroimaging assessment. Establishing an accurate etiological diagnosis and understanding the genetic risk factors for stroke are essential steps to decipher the underlying mechanisms, optimize the design of tailored prevention strategies, and facilitate the identification of novel therapeutic targets in some cases. Despite the increasing recognition of monogenic causes of stroke, genetic disorders remain understudied and therefore under-recognized in children with stroke. Increased awareness among healthcare providers is essential to facilitate accurate diagnosis in a timely manner. In this review, we provide a summary of the main single-gene disorders which may present as ischemic stroke in childhood and describe their clinical manifestations. We provide a set of practical suggestions for the diagnostic work up of these uncommon causes of stroke, based upon the stroke subtype and imaging characteristics that may suggest a monogenic diagnosis of ischemic stroke in children. Current hurdles in the genetic analyses of children with ischemic stroke as well as future prospectives are discussed.

Expanding ACTA2 genotypes with corresponding phenotypes overlapping with smooth muscle dysfunction syndrome

Pathogenic variants in ACTA2, encoding smooth muscle α-actin, predispose to thoracic aortic aneurysms and dissections. ACTA2 variants altering arginine 179 predispose to a more severe, multisystemic disease termed smooth muscle dysfunction syndrome (SMDS; OMIM 613834). Vascular complications of SMDS include patent ductus arteriosus (PDA) or aortopulmonary window, early-onset thoracic aortic disease (TAD), moyamoya-like cerebrovascular disease, and primary pulmonary hypertension. Patients also have dysfunction of other smooth muscle-dependent systems, including congenital mydriasis, hypotonic bladder, and gut hypoperistalsis. Here, we describe five patients with novel heterozygous ACTA2 missense variants, p.Arg179Gly, p.Met46Arg, p.Thr204Ile, p.Arg39Cys, and p.Ile66Asn, who have clinical complications that align or overlap with SMDS. Patients with the ACTA2 p.Arg179Gly and p.Thr204Ile variants display classic features of SMDS. The patient with the ACTA2 p.Met46Arg variant exhibits exclusively vascular complications of SMDS, including early-onset TAD, PDA, and moyamoya-like cerebrovascular disease. The patient with the ACTA2 p.Ile66Asn variant has an unusual vascular complication, a large fusiform internal carotid artery aneurysm. The patient with the ACTA2 p.Arg39Cys variant has pulmonary, gastrointestinal, and genitourinary complications of SMDS but no vascular manifestations. Identifying pathogenic ACTA2 variants associated with features of SMDS is critical for aggressive surveillance and management of vascular and nonvascular complications and delineating the molecular pathogenesis of SMDS.

Triple bypass for multisystem smooth muscle dysfunction syndrome due to Arg179His ACTA2 mutation

Missense mutations in the smooth muscle-specific isoform of the alpha-actin (ACTA2) gene, which encodes smooth muscle actin, congenitally cause systemic smooth muscle dysfunction, leading to multiple systemic smooth muscle dysfunction syndrome. This disease is often diagnosed through the development of congenital mydriasis, patent ductus arteriosus, or thoracic aortic aneurysm at a young age. Some patients develop cerebrovascular lesions, also known as ACTA2 cerebral arteriopathy, which cause ischemic stroke and require surgical revascularization. However, an effective and safe treatment has not yet been established owing to the rarity of the disease. Furthermore, most reports of this disease involve children, with only a few reports on adults and few detailed reports on treatment outcomes published to date. We report a 46-year-old woman with ACTA2 cerebral arteriopathy caused by Arg179His, the most common mutation in this disease; she is the oldest patient reported with this disease to the best of our knowledge. The patient was diagnosed with multiple systemic smooth muscle dysfunction syndrome and ACTA2 cerebral arteriopathy after experiencing a stroke in the right cingulate gyrus. She underwent direct triple bypass with three anastomoses of the right superficial temporal artery to the middle and anterior cerebral arteries. She developed an ischemic stroke as a postoperative complication.The efficacy and safety of this procedure have not been clearly confirmed owing to the frailty of the donor superficial temporal artery and the poor development of collateral circulation; however, direct bypass should be considered a treatment option for patients experiencing progressive multiple strokes.

Effects of chemerin and homocysteine levels and their associations with occurrence and development of ischemic cerebrovascular disease

Background

The current study was conducted to explore the effects of chemerin and homocysteine (Hcy) levels and their associations with the occurrence and development of ischemic cerebrovascular disease (ICVD).

Methods

There involved a total of 187 patients with ICVD and 190 healthy people for physical examination in Cangzhou Central hospital from January 2020 to April 2021. The participants enrolled were divided into four groups based on the digital subtraction angiography: mild stenosis group (64 cases, stenosis rate 30-49 %), moderate stenosis group (72 cases, stenosis rate 50-69 %), severe stenosis group (51 cases, stenosis rate 70-99 %) and control group (190 cases, in healthy condition). The laboratory indexes of ICVD group and control group were observed and the four groups were further compared. Pearson linear correlation was applied to analyze the link between chemerin and Hcy levels and the degree of cerebral vascular stenosis in ICVD patients, and multivariate logistic regression was used to analyze the influencing factors of ICVD.

Results

No significant difference was found in general information including age, gender, body mass index (BMI), heart rate, systolic blood pressure, diastolic blood pressure, smoking and drinking between the two groups (P > 0.05). Moreover, there was no significant difference in fasting blood glucose (FBG), total cholesterol (TC) and high density lipoprotein cholesterol (HDL-C) levels between the two groups (P > 0.05). However, the levels of triglyceride (TG), low density lipoprotein cholesterol (LDL-C), chemerin and Hcy in ICVD group were significantly higher than those in control group (P < 0.05). When comparing the four groups, there was no significant difference in FBG and TC levels (P > 0.05). The levels of TG, LDL-C, chemerin and Hcy in mild, moderate and severe stenosis groups were higher than those in control group, the above levels in moderate and severe stenosis group were higher than those in mild stenosis group, and severe stenosis group higher than moderate stenosis group (P < 0.05). Chemerin and Hcy levels were positively correlated with the degree of cerebral vascular stenosis in ICVD patients (r = 0.612, 0.519, P < 0.001). ICVD was regarded as the dependent variable, and the abovementioned general data as well as significant laboratory indicators, including TG, LDL-C, chemerin and Hcy, as independent variables. The results of multivariate logistic regression analysis revealed that TG, LDL-C, chemerin and Hcy were independent influencing factors of ICVD.

Conclusions

Chemerin and Hcy levels exerted a close link to the occurrence and development of ICVD as independent influencing factors.

Development of a protocol to assess within-subject, regional white matter hyperintensity changes in aging and dementia

BACKGROUND

White matter hyperintensities (WMH), associated with both dementia risk and progression, can individually progress, remain stable, or even regress influencing cognitive decline related to specific cerebrovascular-risks. This study details the development and validation of a registration protocol to assess regional, within-subject, longitudinal WMH changes (ΔWMH) that is currently lacking in the field.

NEW METHOD

3D-FLAIR images (baseline and one-year-visit) were used for protocol development and validation. The method was validated by assessing the correlation between forward and reverse longitudinal registration, and between summated regional progression-regression volumes and Global ΔWMH. The clinical relevance of growth-regression ΔWMH were explored in relation to an executive function test.

RESULTS

MRI scans for 79 participants (73.5 ± 8.8 years) were used in this study. Global ΔWMH vs. summated regional progression-regression volumes were highly associated (r2 = 0.90; p-value < 0.001). Bi-directional registration validated the registration method (r2 = 0.999; p-value < 0.001). Growth and regression, but not overall ΔWMH, were associated with one-year declines in performance on Trial-Making-Test-B.

COMPARISON WITH EXISTING METHOD(S)

This method presents a unique registration protocol for maximum tissue alignment, demonstrating three distinct patterns of longitudinal within-subject ΔWMH (stable, growth and regression).

CONCLUSIONS

These data detail the development and validation of a registration protocol for use in assessing within-subject, voxel-level alterations in WMH volume. The methods developed for registration and intensity correction of longitudinal within-subject FLAIR images allow regional and within-lesion characterization of longitudinal ΔWMH. Assessing the impact of associated cerebrovascular-risks and longitudinal clinical changes in relation to dynamic regional ΔWMH is needed in future studies.