Exploring Gene Expression Profiles in Primary Central Nervous System Vasculitis.

OBJECTIVE: This study was undertaken to explore the gene expression profile of primary central nervous system vasculitis (PCNSV). METHODS: Brain specimens of 4 patients with granulomatous vasculitis (GV), 5 with lymphocytic vasculitis (LV), 4 with amyloid ß-related angiitis (ABRA), and 4 normal controls were studied. RNA-sequencing was performed using the Illumina Hiseq-4,000 platform and the Illumina TruSeq Total-RNA library. Student t test and false discovery rate tests were performed for each of the differentially expressed transcripts. Ingenuity Pathway Analysis was used for the pathway expression analysis. CIBERSORT was used to estimate the abundances of different immune cell subsets in the tissues based on gene expression data. RESULTS: Transcripts differentially expressed between PCNSV and normal brain indicated that endosomal, mitochondrial, and ribosome dysfunction, alterations in protein synthesis, and noncoding RNAs might be involved in PCNSV. Pathway analysis revealed the activation of dendritic cell maturation and antigen processing as well as neuroinflammation in PCNSV versus normal brain, whereas oxidative phosphorylation was inhibited. CIBERSORT estimation of immune cell subsets suggested that activated NK cells, M1 macrophages, memory B cells, and follicular helper T cells were likely to be more prevalent in PCNSV samples. Naïve CD4 T cells and monocytes were mainly estimated to be present in GV and ABRA. Plasma cell and γδ T-cell signatures were mainly found in LV and normal brain. GV showed higher levels of genes associated with macrophage activities and T cells. ABRA showed higher levels of long noncoding RNAs and miR-616. LV showed higher levels of genes encoding immunoglobulins. INTERPRETATION: RNA sequencing confirmed PCNSV heterogeneity. ANN NEUROL 2023;93:120-130.

Moyamoya syndrome in a child with Legius syndrome: Introducing a cerebral vasculopathy to the SPRED1 phenotype?

Legius syndrome is a disorder of the RAS and mitogen-activated protein kinase (MAPK) pathway first described in 2007 by Eric Legius, et al., that has been considered a milder phenotype than reported in the RASopathy neurofibromatosis type 1 (NF1). However, with approximately 200 cases reported in the literature, the Legius syndrome phenotype remains to be fully characterized. We report a child who presented with moyamoya syndrome and who has Legius syndrome due to a pathogenic variant in SPRED1. Vascular complications such as moyamoya syndrome have been reported in NF1. However, this association has not been reported in Legius syndrome. This child's case may represent an expansion of the clinical phenotype of Legius syndrome, and further study is needed. We emphasize the importance of obtaining neuroimaging studies in patients with Legius syndrome who present with new neurologic deficits.

Central nervous system vasculitis: advances in diagnosis.

PURPOSE OF REVIEW: The main purpose of this review is to present advances in diagnostics of central nervous system vasculitis (CNS-V). RECENT FINDINGS: Progress in molecular technologies and neuroimaging have added formidably to our knowledge of CNS-V. Next-generation sequencing has the promise to enhance our ability to diagnose, interrogate, and track infectious diseases, making this test attractive and capable of avoiding brain biopsy in cases where CNS infections are suspected. Further the continuum of neuroimaging progress has advanced our ability to diagnose CNS-V. Our capability to visualize the vessel wall have added a great value in differentiating inflammatory from noninflammatory vasculopathies. New genetic variations are being exposed with exome and genome sequences which will aid future diagnosis. SUMMARY: We have witnessed tremendous advances in CNS-V mainly by our ability to rule out mimics. Progress in molecular technologies, neuroimaging and genetic studies will continue to enhance the field further.

Hereditary leukoencephalopathy with axonal spheroids: a spectrum of phenotypes from CNS vasculitis to parkinsonism in an adult onset leukodystrophy series.

BACKGROUND: Hereditary diffuse leukoencephalopathy with neuroaxonal spheroids (HDLS) is a hereditary, adult onset leukodystrophy which is characterised by the presence of axonal loss, axonal spheroids and variably present pigmented macrophages on pathological examination. It most frequently presents in adulthood with dementia and personality change. HDLS has recently been found to be caused by mutations in the colony stimulating factor-1 receptor (CSF1R) gene. METHODS: In this study, we sequenced the CSF1R gene in a cohort of 48 patients from the UK, Greece and Ireland with adult onset leukodystrophy of unknown cause. RESULTS: Five pathogenic mutations were found, including three novel mutations. The presentations ranged from suspected central nervous system (CNS) vasculitis to extrapyramidal to cognitive phenotypes. The case histories and imaging are presented here, in addition to neuropathological findings from two cases with novel mutations. CONCLUSION: We estimate that CSF1R mutations account for 10% of idiopathic adult onset leukodystrophies and that genetic testing for CSF1R mutations is essential in adult patients presenting with undefined CNS vasculitis or a leukodystrophy with prominent neuropsychiatric signs or dementia.

Pearls & Oy-sters: Homozygous Complement Factor I Deficiency Presenting as Fulminant Relapsing Complement-Mediated CNS Vasculitis.

A 36-year-old man presented multiple times with fever, headache, alteration of mental status, and focal neurologic deficits. MRI revealed extensive white matter lesions that were partially reversed between episodes. Workup revealed persistently low complement factor C3, low factor B, and absent alternative complement pathway activity. Biopsy revealed neutrophilic vasculitis. Genetic testing revealed a homozygous variant in complement factor I (CFI), which was thought to be pathogenic. CFI regulates complement-mediated inflammation, and deficiency in this factor leads to unchecked alternative pathway activity and decrease in C3 and factor B through consumption. The patient has remained stable since starting IL-1ß inhibition. Complement factor I is a rare disorder that should be considered in patients with atypical relapsing neurologic disease associated with neutrophilic pleocytosis.

Divergent roles of glutathione peroxidase-1 (Gpx1) in regulation of leukocyte-endothelial cell interactions in the inflamed cerebral microvasculature.

OBJECTIVE: The aim of this study was to assess the ability of Gpx1 to regulate leukocyte-endothelial cell interactions in the cerebral microcirculation under inflammatory conditions associated with oxidative stress. METHODS: To induce cerebral inflammation, wild-type and Gpx1(-/-) mice underwent systemic treatment with TNF or transient focal cerebral ischemia via MCAO. Leukocyte rolling and adhesion in cerebral postcapillary venules were assessed by intravital microscopy. RESULTS: Absence of Gpx1(-/-) resulted in increased cerebral oxidant production in response to TNF. Under these conditions, leukocyte rolling in cerebral venules was significantly elevated in Gpx1(-/-) mice, whereas leukocyte adhesion was lower than that in wild-type mice. Despite this, expression of key adhesion molecules did not differ between the strains. Following MCAO, Gpx1(-/-) mice displayed significant reductions in rolling and adhesion associated with severe blood flow restriction. In contrast, following treatment with the anti-oxidant ebselen to equalize postischemic cerebral blood flow in wild-type and Gpx1(-/-) mice, absence of Gpx1 was associated with significant elevations in leukocyte interactions. CONCLUSIONS: These data show that under some inflammatory conditions, Gpx1 regulates leukocyte-endothelial cell interactions in the cerebral microvasculature, but that this is affected by the nature of the inflammatory insult.

Association of tumor necrosis factor-α and matrix metalloproteinase-3 gene variants with stroke.

BACKGROUND AND PURPOSE: There is increasing evidence that the genetic variation in the genes coding for pro-inflammatory markers and matrix metalloproteinase may play an important role in the pathogenesis of various human diseases including stroke. The aim of this study was to evaluate the association of genetic variants within the genes encoding tumor necrosis factor-α (TNF-α) and matrix metalloproteinase-3 (MMP-3), with stroke. METHODS: Five hundred and twenty-five ischemic stroke patients and 500 age- and sex-matched controls were included in this study. We analyzed +488 G/A polymorphism in TNF-α gene and -1612 5A/6A polymorphism in MMP-3 gene. The genotypes were determined by Amplification Refractory Mutation System PCR. The strength of association between genotypes and stroke was measured by the odds ratio with 95% confidence interval (CI) and chi-squared analysis. RESULTS: Allelic and genotypic frequencies of TNF-α G/A polymorphism differed significantly between patients and healthy controls (P < 0.001). A stepwise logistic regression analysis confirmed these findings (P < 0.001). Further, evaluating the association of this polymorphism with stroke subtypes, we found significant association with intracranial large artery atherosclerosis, extracranial large artery atherosclerosis, and stroke of undetermined etiology. As far as MMP-3-1612 5A/6A polymorphism is concerned, there was no significant difference in genotypic distribution and allelic frequency between the patients and healthy controls (P = 0.5 and 0.9, respectively). We tested the gene-gene interaction between TNF-α and MMP-3 genes using the logistic regression model. However, there was no evidence for a gene-gene interaction between TNF-α and MMP-3. CONCLUSION: TNF-α +488 G/A variant is an important risk factor for ischemic stroke in the South Indians from Andhra Pradesh, whereas MMP-3-1612 5A/6A polymorphism is not associated with stroke in the same population.

Absence of glutathione peroxidase-1 exacerbates cerebral ischemia-reperfusion injury by reducing post-ischemic microvascular perfusion.

Mice deficient in the anti-oxidant enzyme glutathione peroxidase-1 (Gpx1) have a greater susceptibility to cerebral injury following a localized ischemic event. Much of the response to ischemia-reperfusion is caused by aberrant responses within the microvasculature, including inflammation, diminished endothelial barrier function (increased vascular permeability), endothelial activation, and reduced microvascular perfusion. However, the role of Gpx1 in regulating these responses has not been investigated. Wild-type and Gpx1-/- mice underwent focal cerebral ischemia via mid-cerebral artery occlusion followed by measurement of cerebral perfusion via laser Doppler and intravital microscopy. Post-ischemic brains in wild-type mice displayed significant deficit in microvascular perfusion. However, in Gpx1-/- mice, the deficit in cerebral blood flow was significantly greater than that in wild-type mice, and this was associated with significant increase in infarct size and increased vascular permeability. Ischemia-reperfusion also resulted in expression of matrix metalloproteinase-9 (MMP-9) in endothelial cells. The absence of Gpx1 was associated with marked increase in pro-MMP-9 expression as well as potentiated MMP-9 activity. Pre-treatment of Gpx1-/- mice with the anti-oxidant ebselen restored microvascular perfusion, limited the induction and activation of MMP-9, and attenuated the increases in infarct size and vascular permeability. These findings demonstrate that the anti-oxidant function of Gpx1 plays a critical role in protecting the cerebral microvasculature against ischemia-reperfusion injury by preserving microvascular perfusion and inhibiting MMP-9 expression.

TGFbeta receptor II gene deletion in leucocytes prevents cerebral vasculitis in bacterial meningitis.

In bacterial meningitis, chemokines lead to recruitment of polymorphonuclear leucocytes (PMN) into the CNS. At the site of infection in the subarachnoid space, PMN release reactive oxygen species, reactive nitrogen intermediates (RNI) and interleukin-1beta (IL-1beta). Although these immune factors assist in clearance of bacteria, they also result in neuronal injury associated with meningitis. Transforming growth factor beta (TGFbeta) is a potent deactivator of PMN and macrophages since TGFbeta suppresses the production of ROI, RNI and IL-1. Here, we report that the deletion of the TGFbeta receptor II gene in PMN enhances PMN recruitment into the CNS of mice with Streptococcus pneumoniae meningitis. This was associated with more efficient clearance of bacteria, and almost complete prevention of intracerebral necrotizing vasculitis. Differences in PMN in the CNS of infected control mice and mice lacking TGFbeta receptor II were not explained by altered expression of chemokines acting on PMN. Instead, TGFbeta was found to impair the expression of L (leucocyte)-selectin on PMN from control mice but not from mice lacking TGFbeta receptor II. L-selectin is known to be essential for PMN recruitment in bacterial meningitis. We conclude that defective TGFbeta signalling in PMN is beneficial in bacterial meningitis by ameliorating migration of PMN and bacterial clearance.

Association of primary central nervous system vasculitis with the presence of specific human leucocyte antigen gene variant.

OBJECTIVES: The etiology and genetic susceptibility of primary central nervous system vasculitis (PCNSV) are still unclear. PATIENTS AND METHODS: We analyzed the DNA of 25 Caucasian patients with PCNSV for human leucocyte antigen genes HLA-A, HLA-B, HLA-DRB1, and HLA-DQB1, respectively. HLA-frequencies of the 25 patients with PCNSV were compared with HLA-frequencies of matched Caucasian controls. RESULTS: No statistically significant associations were found for HLA-B, HLA-DR1 and HLA-DQB1 variant. In the PCNSV group, only the HLA-A*69 variant was found more often than expected statistically. CONCLUSION: The results of this study indicate a potential association of HLA marker with PCNSV in Caucasian patients. Further studies are needed to elucidate the role of genes within the human major histocompatibility complex in the pathogenesis of this angiopathy.

[A case of amyloid-ß-related cerebral angiitis with ApoE ε4/ε2 genotype].

A 53-year-old male with a past medical history of hypertension and bipolar disorder gradually developed gait disturbance and cognitive dysfunction over half a year. His cranial MRI showed an area of hyperintensity in the right occipital lobe on T2 weighted images and the surface of the lesion was enhanced along the sulci. We diagnosed his condition as amyloid-ß-related angiitis (ABRA) based on brain biopsy. Repeated, frequent seizures resistant to several antiepileptic drugs (AEDs) occurred after the operation. Steroid therapy was effective and the symptoms, including the intractable seizures and MRI abnormalities dramatically improved. In contrast to the common wild type ε3/ε3 ApoE genotype, a majority of ABRA patients have ε4/ε4. However, in this case the rare ε4/ε2 type was detected. The ε4 allele is considered to promote Aß deposition on the vessel wall, and ε2 is speculated to trigger vessel ruptures or vascular inflammation. Although seizure is not a common complication of brain biopsy, it occurred repeatedly and responded poorly to AEDs in this case. Surgical stress in this patient with ε2 probably induced the uncontrolled seizures. ApoE genotype may be an effective and low-invasive marker in case of suspected ABRA and in predicting the risks of the complication from brain biopsy.

ADAMTS13 reduces VWF-mediated acute inflammation following focal cerebral ischemia in mice.

BACKGROUND: ADAMTS13 cleaves hyperactive ultra-large von Willebrand factor (ULVWF) multimers into smaller and less active forms. It remains unknown whether VWF-mediated inflammatory processes play a role in the enhanced brain injury due to ADAMTS13 deficiency. OBJECTIVE: We tested the hypothesis that the deleterious effect of ADAMTS13 deficiency on ischemic brain injury is mediated through VWF-dependent enhanced vascular inflammation. METHODS: Transient focal cerebral ischemia was induced by 60 min of occlusion of the right middle cerebral artery. Myeloperoxidase (MPO) activity and inflammatory cytokines in the infarcted region were evaluated 23 h after reperfusion injury. Neutrophil infiltration within the infarct and surrounding areas was quantitated by immunohistochemistry. RESULTS: We report that ADAMTS13-deficient mice exhibited significantly enlarged infarct size, concordant with increased myeloperoxidase (MPO) activity, neutrophil infiltration and expression of the pro-inflammatory cytokines interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α). In contrast, VWF-deficient mice exhibited significantly reduced MPO activity, neutrophil infiltration and inflammatory cytokine induction, demonstrating a role of VWF in these inflammatory processes. Mice deficient for both ADAMTS13 and VWF exhibited an identical reduction of the same inflammatory parameters, demonstrating that the increased inflammation observed in ADAMTS13-deficient mice is VWF dependent. Finally, the increased infarct size observed in ADAMTS13-deficient mice was completely abrogated by prior immunodepletion of neutrophils, demonstrating a causal role for acute inflammation in the enhanced brain injury that occurs in the setting of ADAMTS13 deficiency. CONCLUSION: These findings provide new evidence for ADAMTS13 in reducing VWF-mediated acute cerebral inflammation following ischemic stroke.

MELAS masquerading as a systemic vasculitis.

Mitochondrial encephalomyopathy, lactic acidosis, and stroke (MELAS) is a mitochondrial genetic disorder caused by a point mutation, resulting in the substitution of guanine for adenine at nucleotide 3243 (A3243G). It is a multisystem disorder with variable manifestations and typically presents between the first and third decades of life. It should be suspected if a patient exhibits stroke-like episodes before age 40, encephalopathy characterized by seizures, dementia, or both, and lactic acidosis, ragged-red fibers in muscle, or both. We present the case of a 26-year-old white man suspected with primary central nervous system vasculitis admitted to our facility with profound constipation from severe intestinal dysmotility. Although his gastrointestinal and neurologic symptoms did not meet criteria for a specific vasculitic syndrome, his symptoms and blood test abnormalities were concerning for such a process. MELAS was included in our differential diagnosis because his symptoms failed to fit a defined vasculitic process. When genetic testing documented the presence of the point mutation A3243G, his diagnosis was changed. This case illustrates the importance of considering a mitochondrial genetic disorder in the differential diagnosis of patients who present to Rheumatologists with suspected unusual or atypical vasculitic symptoms.

Pediatric granulomatous arthritis: an international registry.

OBJECTIVE: Blau syndrome and its sporadic counterpart, early-onset sarcoidosis, share an identical phenotype featuring the classic triad of arthritis, dermatitis, and uveitis and are associated with mutations of CARD15 in 50-90% of cases. We chose the term "pediatric granulomatous arthritis" to refer to both. An international registry was established in the spring of 2005 to define the phenotype spectrum and establish the mutation frequency and variants. METHODS: Histologically confirmed granuloma and arthritis were required for inclusion. Probands and relatives were genotyped for CARD15. Deidentified clinical information was collected. RESULTS: One year after the inception of the registry, 61 individuals from 22 pedigrees had been entered. Seven pedigrees with 19 individuals (8 affected, 11 unaffected) had clinical disease that was atypical, and none of the individuals in those pedigrees showed mutations. There were 9 classic simplex pediatric granulomatous arthritis pedigrees including 19 individuals (9 affected, 10 unaffected) and 6 classic multiplex pedigrees with 22 individuals (17 affected, 5 unaffected). Cutaneous presentation was the most common. Arthritis was polyarticular in 96% of patients. Isolated eye disease was never the presenting symptom, but significant/severe visual impairment was observed in 41% of patients. Eye disease was bilateral in 21 of 22 patients and was complicated by glaucoma in 6 of 22 patients and by cataracts in 50% of patients. Skin biopsy was the best diagnostic approach (because of accuracy and low invasiveness). CONCLUSION: In this series, the first combining familial and sporadic pedigrees and, to our knowledge, the largest, we further defined the phenotype and showed that all affected classic (and no nonclassic) pedigrees carry a mutation and that there is no asymptomatic carriage. If these data are confirmed, mutation analysis rather than tissue sampling may prove to be the most efficient diagnostic procedure.

An adult case of leukoencephalopathy with intracranial calcifications and cysts.

We describe a 44-year-old woman with progressive headache, ataxia, and seizures in association with multifocal cerebral and cerebellar leukoencephalopathy, intracranial calcifications, and cysts. The cause of death was intracerebellar hemorrhage while taking warfarin. Pathologic features on biopsy included angiomatous-like blood vessels, intense gliosis, and Rosenthal fiber formation in the white matter. Genetic analyses did not identify any significant mutations in two candidate genes.

Distinguishing primary angiitis of the central nervous system from cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy: the importance of family history.

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is a genetically linked neurologic disease characterized by recurrent strokes and progressive or stepwise dementia, with or without migraine-like headaches, seizures, and pseudobulbar palsy. We describe a patient referred with a diagnosis of treatment-refractory primary angiitis of the central nervous system. Meningocortical and skin biopsies confirmed that the patient had CADASIL. Clinical and radiographic differences in these disorders may be subtle, but awareness of them is crucial if the patient is to avoid unnecessary exposure to potentially deleterious immunosuppressive therapy.