RVCL-S and CADASIL display distinct impaired vascular function

NFL and GFAP in (pre)symptomatic RVCL-S carriers: a monogenic cerebral small vessel disease

BACKGROUND

Neurofilament light chain (NfL) and glial fibrillary acidic protein (GFAP) have emerged as biomarkers for cerebral small vessel disease (SVD). We investigated their role in a hereditary SVD model, retinal vasculopathy with cerebral leukoencephalopathy and systemic manifestations (RVCL-S).

METHODS

NfL and GFAP levels of 17 pre-symptomatic, 22 symptomatic RVCL-S mutation carriers and 69 controls were measured using a Simoa assay. We assessed the association of serum and cerebrospinal fluid (CSF) levels of NfL and GFAP with RVCL-S symptomatology and neuropsychological functioning.

RESULTS

Serum and CSF NfL levels were higher in symptomatic RVCL-S compared to controls ≥ 45 years (33.5 pg/mL vs. 9.2 pg/mL, p < 0.01; 8.5*102 pg/mL vs. 3.9*102 pg/mL, p < 0.01, respectively). Serum NfL levels were higher in symptomatic RVCL-S than pre-symptomatic carriers (33.5 pg/mL vs. 5.9 pg/mL, p = 0.02). Pre-symptomatic RVCL-S carriers had increased CSF NfL levels compared to controls < 45 years (5.2*102 pg/mL vs. 1.9*102 pg/mL, p < 0.01). No differences were found in GFAP levels across groups, but in RVCL-S carriers higher serum levels of both NfL and GFAP were linked to poorer global cognitive functioning (β[95%CI] = - 2.86 [- 5.58 to - 0.13], p = 0.04 and β[95%CI] =  - 6.85 [- 11.54 to - 2.15], p = 0.01, respectively) and prolonged psychomotor test times (β[95%CI] = 6.71 [0.78-12.65], p = 0.03 and β[95%CI] = 13.84 [3.09-24.60], p = 0.01).

DISCUSSION

Higher levels of serum NfL and GFAP are associated with worse cognitive functioning in RVCL-S carriers and may serve as marker for disease progression. CSF NfL levels may serve as early marker as pre-symptomatic RVCL-S patients already show differences compared to young controls.

TREX1 p.A129fs and p.Y305C variants in a large multi-ethnic cohort of CADASIL-like unrelated patients

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) and retinal vasculopathy with cerebral leukodystrophy and systemic manifestations (RVCL-S) are the most common forms of rare monogenic early-onset cerebral small vessel disease and share clinical, and, to different extents, neuroradiological and neuropathological features. However, whether CADASIL and RVCL-S overlapping phenotype may be explained by shared genetic risk or causative factors such as TREX1 coding variants remains poorly understood. To investigate this intriguing hypothesis, we used exome sequencing to screen TREX1 protein-coding variability in a large multi-ethnic cohort of 180 early-onset independent familial and apparently sporadic CADASIL-like Caucasian patients from the USA, Portugal, Finland, Serbia and Turkey. We report 2 very rare and likely pathogenic TREX1 mutations: a loss of function mutation (p.Ala129fs) clustering in the catalytic domain, in an apparently sporadic 46-year-old patient from the USA and a missense mutation (p.Tyr305Cys) in the well conserved C-terminal region, in a 57-year-old patient with positive family history from Serbia. In concert with recent findings, our study expands the clinical spectrum of diseases associated with TREX1 mutations.

Genetics of migraine: Delineation of contemporary understanding of the genetic underpinning of migraine

Migraine is a disabling episodic brain disorder with an increased familial relative risk, an increased concordance in monozygotic twins, and an estimated heritability of approximately 50%. Various genetic approaches have been applied to identify genetic factors conferring migraine risk. Initially, candidate gene associations studies (CGAS) have been performed that test DNA variants in genes prioritized based on presumed a priori knowledge of migraine pathophysiology. More recently, genome-wide association studies (GWAS) are applied that test genetic variants, single-nucleotide polymorphisms (SNPs), in a hypothesis-free manner. To date, GWAS have identified ~40 genetic loci associated with migraine. New GWAS data, which are expected to come out soon, will reveal over 100 loci. Also, large-scale GWAS, which have appeared for many traits over the last decade, have enabled studying the overlap in genetic architecture between migraine and its comorbid disorders. Importantly, other genetic factors that cannot be identified by a GWAS approach also confer risk for migraine. First steps have been taken to determine the contribution of these mechanisms by investigating mitochondrial DNA and epigenetic mechanisms. In addition to typical epigenetic mechanisms, that is, DNA methylation and histone modifications, also RNA-based mechanisms regulating gene silencing and activation have recently gotten attention. Regardless, until now, most relevant genetic discoveries related to migraine still come from investigating monogenetic syndromes with migraine as a prominent part of the phenotype. Experimental studies on these syndromes have expanded our knowledge on the mechanisms underlying migraine pathophysiology. It can be envisaged that when all (epi)genetic and phenotypic data on the common and rare forms of migraine will be integrated, this will help to unravel the biological mechanisms for migraine, which will likely guide decision-making in clinical practice in the future.

Optical coherence tomography angiography biomarkers of microvascular alterations in RVCL-S

Background

The brain and retina share many neuronal and vasculature characteristics. We investigated the retinal microvasculature in patients with a monogenic vasculopathy using optical coherence tomography angiography (OCTA). OCT-A is a novel precise non-invasive imaging method that may provide biomarkers suitable for diagnosis and follow-up of small vessel diseases.

Methods

In this exploratory cross-sectional study, eleven RVCL-S patients and eleven age-matched healthy control participants were included. The size of the foveal avascular zone (FAZ) and the vascular density of the superficial capillary networks in the retina were measured by OCT-A.

Results

The symptomatic and presymptomatic patients showed significantly lower vascular density values than controls in the foveal region [median (IQR) 18.2% (15.8–18.6) vs. 24.4% (21.5–26.8) (p < 0.001), 29.8% (29.6–30.8) vs. 33.2% (32.0–33.6) (p = 0.002), respectively]. The FAZ was significantly larger in the symptomatic RVCL-S patients than in the control group [13,416 square pixels [7,529–22,860] vs. 1,405 square pixels [1,344–2,470] (p < 0.001)]. No significant difference was identified in measurements of FAZ comparing presymptomatic and controls.

Conclusion

Our findings with OCT-A demonstrated that RVCL-S causes an increase in the size of the FAZ in symptomatic RVCL-S patients compared to healthy participants. Moreover, there is a decrease in vessel density in the superficial capillary networks in both symptomatic and presymptomatic patients. In the future, newly developed precise objective instruments such as OCT (-A) may provide important tools in determining disease activity for follow up of common small vessel diseases.

Spectral Domain Optical Coherence Tomography in Retinal Vasculopathy With Cerebral Leukoencephalopathy and Systemic Manifestations: A Monogenic Small Vessel Disease

BACKGROUND

Retinal vasculopathy with cerebral leukoencephalopathy and systemic manifestations (RVCL-S) is a monogenic small vessel disease caused by mutations in TREX1. Several organs, including retina and brain, are affected. Analyzing retinal anatomy is increasingly used as a biomarker for ophthalmological and neurological disorders (due to the shared embryological origin of retina and brain). Optical coherence tomography (OCT) provides a noninvasive cross-sectional visualization of optic disc and macula. We aimed to use OCT to investigate retinal layer thickness in RVCL-S.

METHODS

Cross-sectional, 17 TREX1 mutation carriers (34 eyes) and 9 controls (18 eyes) underwent comprehensive ophthalmologic assessment followed by spectral domain OCT for measuring peripapillary retinal nerve fiber layer (pRNFL) thickness and total macular volume (TMV). Secondary outcomes included measuring thickness of individual macular retinal layers and peripapillary sectors. Findings were analyzed using generalized estimating equations to account for intereye correlation.

RESULTS

TREX1 mutation carriers had decreased pRNFL thickness (median [interquartile range] 76 [60-99] vs 99 [87-108] µm, P < 0.001) and TMV (8.1 [7.4-8.5] vs 8.7 [8.4-8.8] mm3, P = 0.006) compared with controls. With the exception of the temporal sector, the thickness of all peripapillary sectors was decreased in TREX1 mutation carriers. Ganglion cell layer (30 [22-37] vs 39 [36-41] µm, P < 0.001) and inner plexiform layer (27 [24-34] vs 34 [31-35], P = 0.001) were thinner in TREX1 mutation carriers. Notably, in 9 of 12 eyes with normal funduscopic examination, retinal thinning was already detected.

CONCLUSIONS

RVCL-S, which may serve as a vascular retinopathy model, is associated with retinal thinning in the peripapillary and macular area. OCT findings can potentially serve as early biomarkers for RVCL-S and other vascular retinopathies.

Retinal Vasculopathy with Cerebral Leukoencephalopathy and Systemic manifestations (RVCL-S): An update on basic science and clinical perspectives

Retinal vasculopathy with cerebral leukoencephalopathy and systemic manifestations (RVCL-S) is a rare, underrecognized, systemic small vessel disease caused by heterozygous C-terminal truncating TREX1 mutations. The disease is characterized by vascular retinopathy, focal neurological complaints, cognitive decline and a wide range of systemic manifestations, including Raynaud's phenomenon, anemia and liver and kidney disease. Eventually, RVCL-S leads to premature death. The underlying pathological finding in RVCL-S is a nonatherosclerotic, amyloid-negative angiopathy involving small arteries and capillaries. However, the exact mechanisms by which the truncated TREX1 protein causes angiopathy remains unknown. Timely recognition of this disease is important to slow down and treat complications of the disorder, but also to prevent unnecessary (invasive) diagnostic or therapeutic procedures. As we move forward, translational research combining basic science advances and clinical findings as well as studies focusing on natural history following RVCL-S patients at different disease stages, will be critical to help elucidate RVCL-S pathophysiology. These studies will also provide the tools to identify appropriate biomarkers and therapeutic agent options for RVCL-S patients.

Biomarkers Related to Endothelial Dysfunction and Vascular Cognitive Impairment: A Systematic Review

INTRODUCTION

The damage in the endothelium and the neurovascular unit appears to play a key role in the pathogenesis of vascular cognitive impairment (VCI). Although there have been many advances in understanding the physiopathology of this disease, several questions remain unanswered. The association with other degenerative diseases and the heterogeneity of its clinical spectrum establish a diagnostic problem, compromising a better comprehension of the pathology and halting the development of effective treatments. The investigation of biomarkers is an important movement to the development of novel explicative models and treatment targets involved in VCI.

METHODS

We searched MEDLINE considering the original research based on VCI biomarkers in the past 20 years, following prespecified selection criteria, data extraction, and qualitative synthesis.

RESULTS

We reviewed 42 articles: 16 investigated plasma markers, 17 analyzed neuropathological markers, 4 studied CSF markers, 4 evaluated neuroimaging markers (ultrasound and MRI), and 1 used peripheral Doppler perfusion imaging.

CONCLUSIONS

The biomarkers in these studies suggest an intrinsic relationship between endothelial dysfunction and VCI. Nonetheless, there is still a need for identification of a distinctive set of markers that can integrate the clinical approach of VCI, improve diagnostic accuracy, and support the discovery of alternative therapies.

Brain MRI in Monogenic Cerebral Small Vessel Diseases: A Practical Handbook

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Monogenic cerebral small vessel diseases are a topic of growing interest, as several genes responsible have been recently described and new sequencing techniques such as Next generation sequencing are available. Brain imaging is a key exam in these diseases. First, since it is often the first exam performed, an MRI is key in selecting patients for genetic testing and for interpreting Next generation sequencing reports. In addition, neuroimaging can be helpful in describing the underlying pathological mechanisms involved in cerebral small vessel disease. With this review, we aim to provide Neurologists and Stroke physicians with an up-to date overview of the current neuroimaging knowledge on monogenic small vessel diseases.

PIP2 corrects cerebral blood flow deficits in small vessel disease by rescuing capillary Kir2.1 activity

Cerebral small vessel diseases (SVDs) are a central link between stroke and dementia-two comorbidities without specific treatments. Despite the emerging consensus that SVDs are initiated in the endothelium, the early mechanisms remain largely unknown. Deficits in on-demand delivery of blood to active brain regions (functional hyperemia) are early manifestations of the underlying pathogenesis. The capillary endothelial cell strong inward-rectifier K⁺ channel Kir2.1, which senses neuronal activity and initiates a propagating electrical signal that dilates upstream arterioles, is a cornerstone of functional hyperemia. Here, using a genetic SVD mouse model, we show that impaired functional hyperemia is caused by diminished Kir2.1 channel activity. We link Kir2.1 deactivation to depletion of phosphatidylinositol 4,5-bisphosphate (PIP₂), a membrane phospholipid essential for Kir2.1 activity. Systemic injection of soluble PIP₂ rapidly restored functional hyperemia in SVD mice, suggesting a possible strategy for rescuing functional hyperemia in brain disorders in which blood flow is disturbed.

Cerebrovascular reactivity in retinal vasculopathy with cerebral leukoencephalopathy and systemic manifestations

Retinal Vasculopathy with Cerebral Leukoencephalopathy and Systemic manifestations (RVCL-S) is a small vessel disease caused by TREX1 mutations. RVCL-S is characterized by retinal vasculopathy and brain white matter lesions with and without contrast enhancement. We aimed to investigate cerebrovascular reactivity (CVR) in RVCL-S. In this cross-sectional observational study, 21 RVCL-S patients, 23 mutation-negative family members, and 31 healthy unrelated controls were included. CVR to a hypercapnic challenge was measured using dual-echo arterial spin labeling magnetic resonance imaging. Stratified analyses based on age were performed. We found that CVR was decreased in gray and white matter of RVCL-S patients compared with family members and healthy controls (ANCOVA; P < 0.05 for all comparisons). This was most noticeable in RVCL-S patients aged ≥40 years (ANCOVA, P < 0.05 for all comparisons). In RVCL-S patients aged < 40 years, only CVR in white matter was lower when compared to healthy controls (P < 0.05). Gray matter CVR was associated with white matter lesion volume in RVCL-S patients (r = -0.527, P = 0.01). In conclusion, impaired cerebrovascular reactivity may play an important role in the pathophysiology of RVCL-S and may be an useful early biomarker of cerebrovascular disease severity.

Genome-wide transcriptome study in skin biopsies reveals an association of E2F4 with cadasil and cognitive impairment

CADASIL is a small vessel disease caused by mutations in NOTCH3 that lead to an odd number of cysteines in the EGF-like repeat domain, causing protein misfolding and aggregation. The main symptoms are migraine, psychiatric disturbances, recurrent strokes and dementia, being executive function characteristically impaired. The molecular pathways altered by this receptor aggregation need to be studied further. A genome-wide transcriptome study (four cases paired with three healthy siblings) was carried out, in addition to a qRT-PCR for validation purposes (ten new cases and eight new controls). To study the expression profile by cell type of the significant mRNAs found, we performed an in situ hybridization (ISH) (nine cases and eight controls) and a research in the Single-nuclei Brain RNA-seq expression browser (SNBREB). Pathway analysis enrichment was carried out with Gene Ontology and Reactome. Neuropsychological tests were performed in five of the qRT-PCR cases. The two most significant differentially expressed mRNAs (BANP, p-value = 7.23 × 10-4 and PDCD6IP, p-value = 8.36 × 10-4) were selected for the validation study by qRT-PCR. Additionally, we selected two more mRNAs (CAMK2G, p-value = 4.52 × 10-3 and E2F4, p-value = 4.77 × 10-3) due to their association with ischemic neuronal death. E2F4 showed differential expression in the genome-wide transcriptome study and in the qRT-PCR (p = 1.23 × 10-3), and it was upregulated in CADASIL cases. Furthermore, higher E2F4 expression was associated with worse executive function (p = 2.04 × 10-2) and attention and information processing speed (IPS) (p = 8.73 × 10-2). In situ hibridization showed E2F4 expression in endothelial and vascular smooth vessel cells. In silico studies indicated that E2F4 is also expressed in brain endothelial cells. Among the most significant pathways analyzed, there was an enrichment of vascular development, cell adhesion and vesicular machinery terms and autophagy process. E2F4 is more highly expressed in the skin biopsy of CADASIL patients compared to controls, and its expression is present in endothelial cells and VSMCs. Further studies are needed to understand whether E2F4 could be useful as a biomarker, to monitor the disease or be used as a therapeutic target.

PIP2 Improves Cerebral Blood Flow in a Mouse Model of Alzheimer's Disease

Alzheimer's disease (AD) is a leading cause of dementia and a substantial healthcare burden. Despite this, few treatment options are available for controlling AD symptoms. Notably, neuronal activity-dependent increases in cortical cerebral blood flow (CBF; functional hyperemia) are attenuated in AD patients, but the associated pathological mechanisms are not fully understood at the molecular level. A fundamental mechanism underlying functional hyperemia is activation of capillary endothelial inward-rectifying K⁺ (Kir2.1) channels by neuronally derived potassium (K⁺), which evokes a retrograde capillary-to-arteriole electrical signal that dilates upstream arterioles, increasing blood delivery to downstream active regions. Here, using a mouse model of familial AD (5xFAD), we tested whether this impairment in functional hyperemia is attributable to reduced activity of capillary Kir2.1 channels. In vivo CBF measurements revealed significant reductions in whisker stimulation (WS)-induced and K⁺-induced hyperemic responses in 5xFAD mice compared with age-matched controls. Notably, measurements of whole-cell currents in freshly isolated 5xFAD capillary endothelial cells showed that Kir2.1 current density was profoundly reduced, suggesting a defect in Kir2.1 function. Because Kir2.1 activity absolutely depends on binding of phosphatidylinositol 4,5-bisphosphate (PIP₂) to the channel, we hypothesized that capillary Kir2.1 channel impairment could be corrected by exogenously supplying PIP₂. As predicted, a PIP₂ analog restored Kir2.1 current density to control levels. More importantly, systemic administration of PIP₂ restored K⁺-induced CBF increases and WS-induced functional hyperemic responses in 5xFAD mice. Collectively, these data provide evidence that PIP₂-mediated restoration of capillary endothelial Kir2.1 function improves neurovascular coupling and CBF in the setting of AD.

The potential danger of blocking CGRP for treating migraine in CADASIL patients

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is an inherited small vessel disease characterised by recurrent ischemic stroke, cognitive decline progressing to dementia, psychiatric disturbances and apathy. More than half of mutation carriers suffer from migraine, most often migraine with aura. Recently, a CADASIL patient was treated with a monoclonal antibody targeting the calcitonin gene-related peptide (CGRP) receptor. Monoclonal antibodies targeting the CGRP system have been demonstrated to be safe, well tolerated, and effective in reducing migraine attacks. There is, however, abundant evidence that CGRP is important in maintaining cardiovascular homeostasis under (patho)physiological conditions. CGRP may act as a vasodilatory safeguard during cerebral and cardiac ischemia and blockage of the system could, therefore, potentially worsen ischemic events. Therefore, we caution against treating patients with small vessel diseases, such as the monogenic disorder CADASIL, with these drugs until relevant safety data and long term follow up results are available. Alternative preventive migraine treatments in CADASIL may be acetazolamide, sodium valproate, lamotrigine, topiramate, verapamil, or flunarizine.

Pediatric Migraine Phenomena and Variants: Don't Let Them Go Over Your Head

PURPOSE OF REVIEW

Primary care providers, general pediatric neurologists, and other related subspecialty providers require a clear understanding of pediatric migraine with typical aura and its variants.

RECENT FINDINGS

We highlight some of the genetic mutations known to contribute to specific types of migraine with aura, discuss the ophthalmologic phenomena of migraine and call attention to some of the earliest manifestations of migraine in children, many of which have correlates in adulthood. While the majority of headaches in children are migraine with or without aura or tension type, many migraine and aura variants exist. Early and accurate diagnosis of episodic syndromes associated with migraine, as defined by the 2018 ICHD-3 criteria, can help to reduce unnecessary imaging, referrals, cost and anxiety, thereby benefiting patients and their families.

Genetics of migraine aura: an update

Migraine is a common brain disorder with a large genetic component. Of the two main migraine types, migraine with aura and migraine without aura, the genetic underpinning in the former is least understood. Given the evidence from epidemiological studies in cohorts and families that the genetic contribution is highest in migraine with aura, this seems paradoxical. Various genetic approaches have been applied to identify genetic factors that confer risk for migraine. Initially, so-called candidate gene associations studies (CGAS) have been performed that test DNA variants in genes prioritized based on presumed a priori knowledge of migraine pathophysiology. More recently, genome-wide association studies (GWAS) tested variants in any gene in an hypothesis-free manner. Whereas GWAS in migraine without aura, or the more general diagnosis migraine have already identified dozens of gene variants, the specific hunt for gene variants in migraine with aura has been disappointing. The only GWAS specifically investigating migraine with aura yielded only one single associated single nucleotide polymorphism (SNP), near MTDH and PGCP, with genome-wide significance. However, interrogation of all genotyped SNPs, so beyond this one significant hit, was more successful and led to the notion that migraine with aura and migraine without aura are genetically more alike than different. Until now, most relevant genetic discoveries related to migraine with aura came from investigating monogenetic syndromes with migraine aura as a prominent phenotype (i.e. FHM, CADASIL and FASPS). This review will highlight the genetic findings relevant to migraine with aura.

Increased Mortality and Vascular Phenotype in a Knock-In Mouse Model of Retinal Vasculopathy With Cerebral Leukoencephalopathy and Systemic Manifestations

Background and Purpose—

Retinal vasculopathy with cerebral leukoencephalopathy and systemic manifestations (RVCL-S) is an autosomal dominant small vessel disease caused by C-terminal frameshift mutations in the TREX1 gene that encodes the major mammalian 3′ to 5′ DNA exonuclease. RVCL-S is characterized by vasculopathy, especially in densely vascularized organs, progressive retinopathy, cerebral microvascular disease, white matter lesions, and migraine, but the underlying mechanisms are unknown.

Methods—

Homozygous transgenic RVCL-S knock-in mice expressing a truncated Trex1 (three prime repair exonuclease 1) protein (similar to what is seen in patients) and wild-type littermates, of various age groups, were subjected to (1) a survival analysis, (2) in vivo postocclusive reactive hyperemia and ex vivo Mulvany myograph studies to characterize the microvascular and macrovascular reactivity, and (3) experimental stroke after transient middle cerebral artery occlusion with neurological deficit assessment.

Results—

The mutant mice show increased mortality starting at midlife ( P =0.03 with hazard ratio, 3.14 [95% CI, 1.05–9.39]). The mutants also show a vascular phenotype as evidenced by attenuated postocclusive reactive hyperemia responses (across all age groups; F[1, 65]=5.7, P =0.02) and lower acetylcholine-induced relaxations in aortae (in 20- to 24-month-old mice; RVCL-S knock-in: E max : 37±8% versus WT: E max : 65±6%, P =0.01). A vascular phenotype is also suggested by the increased infarct volume seen in 12- to 14-month-old mutant mice at 24 hours after infarct onset (RVCL-S knock-in: 75.4±2.7 mm 3 versus WT: 52.9±5.6 mm 3 , P =0.01).

Conclusions—

Homozygous RVCL-S knock-in mice show increased mortality, signs of abnormal vascular function, and increased sensitivity to experimental stroke and can be instrumental to investigate the pathology seen in patients with RVCL-S.

ER stress and Rho kinase activation underlie the vasculopathy of CADASIL

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) leads to premature stroke and vascular dementia. Mechanism-specific therapies for this aggressive cerebral small vessel disease are lacking. CADASIL is caused by NOTCH3 mutations that influence vascular smooth muscle cell (VSMC) function through unknown processes. We investigated molecular mechanisms underlying the vasculopathy in CADASIL focusing on endoplasmic reticulum (ER) stress and RhoA/Rho kinase (ROCK). Peripheral small arteries and VSMCs were isolated from gluteal biopsies of CADASIL patients and mesentery of TgNotch3R169C mice (CADASIL model). CADASIL vessels exhibited impaired vasorelaxation, blunted vasoconstriction, and hypertrophic remodeling. Expression of NOTCH3 and ER stress target genes was amplified and ER stress response, Rho kinase activity, superoxide production, and cytoskeleton-associated protein phosphorylation were increased in CADASIL, processes associated with Nox5 upregulation. Aberrant vascular responses and signaling in CADASIL were ameliorated by inhibitors of Notch3 (γ-secretase inhibitor), Nox5 (mellitin), ER stress (4-phenylbutyric acid), and ROCK (fasudil). Observations in human CADASIL were recapitulated in TgNotch3R169C mice. These findings indicate that vascular dysfunction in CADASIL involves ER stress/ROCK interplay driven by Notch3-induced Nox5 activation and that NOTCH3 mutation-associated vascular pathology, typical in cerebral vessels, also manifests peripherally. We define Notch3-Nox5/ER stress/ROCK signaling as a putative mechanism-specific target and suggest that peripheral artery responses may be an accessible biomarker in CADASIL.

Migraine headache: Is it only a neurological disorder? Links between migraine and cardiovascular disorders

Migraine headache (MH) is a common disorder affecting millions of people in the United States. MH is substantially more prevalent in women compared to men. An association between migraine with or without aura and risk of cardiovascular disease (CVD) has been extensively reported. There are several proposed theories that may explain the pathophysiologic relationship between MH and CVD. This review will summarize the recent literature on this topic and provide an evidence-based perspective regarding the current knowledge and controversies regarding association of MH and CVD.

Aura and Stroke: relationship and what we have learnt from preclinical models

BACKGROUND

Population-based studies have highlighted a close relationship between migraine and stroke. Migraine, especially with aura, is a risk factor for both ischemic and hemorrhagic stroke. Interestingly, stroke risk is highest for migraineurs who are young and otherwise healthy.

MAIN BODY

Preclinical models have provided us with possible mechanisms to explain the increased vulnerability of migraineurs' brains towards ischemia and suggest a key role for enhanced cerebral excitability and increased incidence of microembolic events. Spreading depolarization (SD), a slowly propagating wave of neuronal depolarization, is the electrophysiologic event underlying migraine aura and a known headache trigger. Increased SD susceptibility has been demonstrated in migraine animal models, including transgenic mice carrying human mutations for the migraine-associated syndrome CADASIL and familial hemiplegic migraine (type 1 and 2). Upon experimentally induced SD, these mice develop aura-like neurological symptoms, akin to patients with the respective mutations. Migraine mutant mice also exhibit an increased frequency of ischemia-triggered SDs upon experimental stroke, associated with accelerated infarct growth and worse outcomes. The severe stroke phenotype can be explained by SD-related downstream events that exacerbate the metabolic mismatch, including pericyte contraction and neuroglial inflammation. Pharmacological suppression of the genetically enhanced SD susceptibility normalizes the stroke phenotype in familial hemiplegic migraine mutant mice. Recent epidemiologic and imaging studies suggest that these preclinical findings can be extrapolated to migraine patients. Migraine patients are at risk for particularly cardioembolic stroke. At the same time, studies suggest an increased incidence of coagulopathy, atrial fibrillation and patent foramen ovale among migraineurs, providing a possible path for microembolic induction of SD and, in rare instances, stroke in hyperexcitable brains. Indeed, recent imaging studies document an accelerated infarct progression with only little potentially salvageable brain tissue in acute stroke patients with a migraine history, suggesting an increased vulnerability towards cerebral ischemia.

CONCLUSION

Preclinical models suggest a key role for enhanced SD susceptibility and microembolization to explain both the occurrence of migraine attacks and the increased stroke risk in migraineurs. Therapeutic targeting of SD and microembolic events, or potential causes thereof, will be promising for treatment of aura and may also prevent ischemic infarction in vulnerable brains.

Systemic features of retinal vasculopathy with cerebral leukoencephalopathy and systemic manifestations: a monogenic small vessel disease

BACKGROUND

Retinal vasculopathy with cerebral leukoencephalopathy and systemic manifestations (RVCL-S) is a small vessel disease caused by C-terminal truncating TREX1 mutations. The disease is typically characterized by vascular retinopathy and focal and global brain dysfunction. Systemic manifestations have also been reported but not yet systematically investigated.

METHODS

In a cross-sectional study, we compared the clinical characteristics of 33 TREX1 mutation carriers (MC+) from three Dutch RVCL-S families with those of 37 family members without TREX1 mutation (MC-). All participants were investigated using personal interviews, questionnaires, physical, neurological and neuropsychological examinations, blood and urine tests, and brain MRI.

RESULTS

In MC+, vascular retinopathy and Raynaud's phenomenon were the earliest symptoms presenting from age 20 onwards. Kidney disease became manifest from around age 35, followed by liver disease, anaemia, markers of inflammation and, in some MC+, migraine and subclinical hypothyroidism, all from age 40. Cerebral deficits usually started mildly around age 50, associated with white matter and intracerebral mass lesions, and becoming severe around age 60-65.

CONCLUSIONS

Retinal vasculopathy with cerebral leukoencephalopathy and systemic manifestations is a rare, but likely underdiagnosed, systemic small vessel disease typically starting with vascular retinopathy, followed by multiple internal organ disease, progressive brain dysfunction, and ultimately premature death.