Oscillatory contractile forces refine endothelial cell-cell interactions for continuous lumen formation governed by Heg1/Ccm1.

The formation and organization of complex blood vessel networks rely on various biophysical forces, yet the mechanisms governing endothelial cell-cell interactions under different mechanical inputs are not well understood. Using the dorsal longitudinal anastomotic vessel (DLAV) in zebrafish as a model, we studied the roles of multiple biophysical inputs and cerebral cavernous malformation (CCM)-related genes in angiogenesis. Our research identifies heg1 and krit1 (ccm1) as crucial for the formation of endothelial cell-cell interfaces during anastomosis. In mutants of these genes, cell-cell interfaces are entangled with fragmented apical domains. A Heg1 live reporter demonstrated that Heg1 is dynamically involved in the oscillatory constrictions along cell-cell junctions, whilst a Myosin live reporter indicated that heg1 and krit1 mutants lack actomyosin contractility along these junctions. In wild-type embryos, the oscillatory contractile forces at junctions refine endothelial cell-cell interactions by straightening junctions and eliminating excessive cell-cell interfaces. Conversely, in the absence of junctional contractility, the cell-cell interfaces become entangled and prone to collapse in both mutants, preventing the formation of a continuous luminal space. By restoring junctional contractility via optogenetic activation of RhoA, contorted junctions are straightened and disentangled. Additionally, haemodynamic forces complement actomyosin contractile forces in resolving entangled cell-cell interfaces in both wild-type and mutant embryos. Overall, our study reveals that oscillatory contractile forces governed by Heg1 and Krit1 are essential for maintaining proper endothelial cell-cell interfaces and thus for the formation of a continuous luminal space, which is essential to generate a functional vasculature.

Neuroinflammation Plays a Critical Role in Cerebral Cavernous Malformation Disease.

BACKGROUND: Cerebral cavernous malformations (CCMs) are neurovascular lesions caused by loss of function mutations in 1 of 3 genes, including KRIT1 (CCM1), CCM2, and PDCD10 (CCM3). CCMs affect ≈1 out of 200 children and adults, and no pharmacologic therapy is available. CCM lesion count, size, and aggressiveness vary widely among patients of similar ages with the same mutation or even within members of the same family. However, what determines the transition from quiescent lesions into mature and active (aggressive) CCM lesions is unknown. METHODS: We use genetic, RNA-sequencing, histology, flow cytometry, and imaging techniques to report the interaction between CCM endothelium, astrocytes, leukocytes, microglia/macrophages, neutrophils (CCM endothelium, astrocytes, leukocytes, microglia/macrophages, neutrophils interaction) during the pathogenesis of CCMs in the brain tissue. RESULTS: Expression profile of astrocytes in adult mouse brains using translated mRNAs obtained from the purification of EGFP (enhanced green fluorescent protein)-tagged ribosomes (Aldh1l1-EGFP/Rpl10a) in the presence or absence of CCM lesions (Slco1c1-iCreERT2;Pdcd10fl/fl; Pdcd10BECKO) identifies a novel gene signature for neuroinflammatory astrocytes. CCM-induced reactive astrocytes have a neuroinflammatory capacity by expressing genes involved in angiogenesis, chemotaxis, hypoxia signaling, and inflammation. RNA-sequencing analysis on RNA isolated from brain endothelial cells in chronic Pdcd10BECKO mice (CCM endothelium), identified crucial genes involved in recruiting inflammatory cells and thrombus formation through chemotaxis and coagulation pathways. In addition, CCM endothelium was associated with increased expression of Nlrp3 and Il1b. Pharmacological inhibition of NLRP3 (NOD [nucleotide-binding oligomerization domain]-' LRR [leucine-rich repeat]- and pyrin domain-containing protein 3) significantly decreased inflammasome activity as assessed by quantification of a fluorescent indicator of caspase-1 activity (FAM-FLICA [carboxyfluorescein-fluorochrome-labeled inhibitors of caspases] caspase-1) in brain endothelial cells from Pdcd10BECKO in chronic stage. Importantly, our results support the hypothesis of the crosstalk between astrocytes and CCM endothelium that can trigger recruitment of inflammatory cells arising from brain parenchyma (microglia) and the peripheral immune system (leukocytes) into mature active CCM lesions that propagate lesion growth, immunothrombosis, and bleedings. Unexpectedly, partial or total loss of brain endothelial NF-κB (nuclear factor κB) activity (using Ikkbfl/fl mice) in chronic Pdcd10BECKO mice does not prevent lesion genesis or neuroinflammation. Instead, this resulted in a trend increase in the number of lesions and immunothrombosis, suggesting that therapeutic approaches designed to target inflammation through endothelial NF-κB inhibition may contribute to detrimental side effects. CONCLUSIONS: Our study reveals previously unknown links between neuroinflammatory astrocytes and inflamed CCM endothelium as contributors that trigger leukocyte recruitment and precipitate immunothrombosis in CCM lesions. However, therapeutic approaches targeting brain endothelial NF-κB activity may contribute to detrimental side effects.

Somatic variants of MAP3K3 are sufficient to cause cerebral and spinal cord cavernous malformations.

Cerebral cavernous malformations (CCMs) and spinal cord cavernous malformations (SCCMs) are common vascular abnormalities of the CNS that can lead to seizure, haemorrhage and other neurological deficits. Approximately 85% of patients present with sporadic (versus congenital) CCMs. Somatic mutations in MAP3K3 and PIK3CA were recently reported in patients with sporadic CCM, yet it remains unknown whether MAP3K3 mutation is sufficient to induce CCMs. Here we analysed whole-exome sequencing data for patients with CCM and found that ∼40% of them have a single, specific MAP3K3 mutation [c.1323C>G (p.Ile441Met)] but not any other known mutations in CCM-related genes. We developed a mouse model of CCM with MAP3K3I441M uniquely expressed in the endothelium of the CNS. We detected pathological phenotypes similar to those found in patients with MAP3K3I441M. The combination of in vivo imaging and genetic labelling revealed that CCMs were initiated with endothelial expansion followed by disruption of the blood-brain barrier. Experiments with our MAP3K3I441M mouse model demonstrated that CCM can be alleviated by treatment with rapamycin, the mTOR inhibitor. CCM pathogenesis has usually been attributed to acquisition of two or three distinct genetic mutations involving the genes CCM1/2/3 and/or PIK3CA. However, our results demonstrate that a single genetic hit is sufficient to cause CCMs.

Plasma water T2 detects age-stratified differences in cardiometabolic health among familial CCM patients with Hispanic CCM1 mutation.

Cerebral cavernous malformations (CCMs) are abnormal clusters of capillaries in the nervous system. This pilot study analyzed the cardiometabolic health status of individuals with familial CCMs caused by a rare mutation in the CCM1 gene (fCCM1). The aim was to compare plasma water T2 values from individuals with fCCM1 with values from metabolically unhealthy and healthy individuals with no known CCM mutations. This observational, cross-sectional study included 75 participants: 11 fCCM1 patients, 24 metabolically unhealthy and 40 metabolically healthy individuals. Plasma water T2, an early, global and practical marker of cardiometabolic health, was measured in the time domain using benchtop magnetic resonance relaxometry. The results were stratified by age (equal to or less than 45 vs. older than 45 years). Group means were compared using Welch's one-way ANOVA and post hoc Tukey-Kramer tests. Multivariable linear regression, with T2 as the outcome variable, was used to explore associations with age, gender, Hispanic ethnicity and fCCM1 status. In the younger age stratum, the fCCM1 group had a mean plasma water T2 value comparable to the metabolically healthy group (p = 0.6388), but higher than the unhealthy group (p < 0.0001). By contrast, in the older stratum, the mean plasma water T2 value for the fCCM1 group was comparable to the metabolically unhealthy group (p = 0.7819) and lower than the healthy group (p = 0.0005). Multivariable linear regression revealed that age and the interaction between age and fCCM1 status were significant predictors of T2, even after adjusting for gender and Hispanic ethnicity. Plasma water T2 shows potential as a biomarker for assessing the health status of individuals with fCCM1. Further research is needed to validate these preliminary observations and elucidate the association between CCMs and cardiometabolic health.

Fully endoscopic approach for resection of brainstem cavernous malformations: a systematic review of the literature.

BACKGROUND: Brainstem cavernous malformations (BCMs) are benign lesions that typically have an acute onset and are associated with a high rate of morbidity. The selection of the optimal surgical approach is crucial for obtaining favorable outcomes, considering the different anatomical locations of various brainstem lesions. Endoscopic surgery is increasingly utilized in treating of BCMs, owing to its depth illumination and panoramic view capabilities. For intra-axial ventral BCMs, the best surgical options are endoscopic endonasal approaches, following the "two-point method. For cavernous hemangiomas on the dorsal side of the brainstem, endoscopy proves valuable by providing enhanced visualization of the operative field and minimizing the need for brain retraction. METHODS: In this review, we gathered data on the fully endoscopic approach for the resection of BCMs, and outlined technical notes and tips. Total of 15 articles were included in this review. The endoscopic endonasal approach was utilized in 19 patients, and the endoscopic transcranial approach was performed in 3 patients. RESULTS: The overall resection rate was 81.8% (18/22). Among the 19 cases of endoscopic endonasal surgery, postoperative cerebrospinal fluid (CSF) leakage occurred in 5 cases, with lesions exceeding 2 cm in diameter in 3 patients with postoperative CSF rhinorrhea. Among the 20 patients with follow-up data, 2 showed no significant improvement after surgery, whereas the remaining 18 patients showed significant improvement compared to their admission symptoms. CONCLUSIONS: This systematic literature review demonstrates that a fully endoscopic approach is a safe and effective option for the resection of BCMs. Further, it can be considered an alternative to conventional craniotomy, particularly when managed by a neurosurgical team with extensive experience in endoscopic surgery, addressing these challenging lesions.

Clinical features, hemorrhage risk and epilepsy outcomes of familial cerebral cavernous malformation: A 20-year observational pragmatic single-center study.

INTRODUCTION: Familial Cerebral Cavernous Malformations (fCCMs) are rare, hereditary conditions characterized by multiple central nervous system lesions. Despite their rarity, CCMs can cause significant clinical challenges when symptomatic, manifesting as seizure and symptomatic hemorrhage (CASH). Guidelines suggest neurosurgical intervention for symptomatic or previously symptomatic lesions, while conservative management is recommended for new-onset epilepsy. However, the natural history and optimal management remain unclear, necessitating further research. OBJECTIVE: This study aims to provide a comprehensive analysis of the clinical features, hemorrhage risk, and epilepsy outcomes in fCCM patients over an extended follow-up period, offering a more precise estimate of CASH and epilepsy rates in this population. METHODS: This retrospective longitudinal cohort study included fCCM patients enrolled from 2001 to May 2024. Data collected included demographic information, new neurological symptoms, symptomatic hemorrhages, seizures, and modified Rankin Scale (mRS) scores. Incidence rates of first symptomatic events and Kaplan-Meier survival curves were calculated, with logistic and Cox-proportional hazard regression models used to evaluate outcomes. RESULTS: A total of 47 patients were included in this study, with a mean age at diagnosis of 37.51 years. At diagnosis, 68 % were symptomatic, with 30 % having CASH and 36 % experiencing seizures without CASH. During a median follow-up of 126.0 months (interquartile range, 110.5 months), 17 % had a new CASH event, 20 % had seizures without CASH, and 60 % remained asymptomatic. The bleeding rate was 1.02 % per patient-year, with new focal neurological symptoms at 2.045 per 1000 patient-years and new CASH at 10.225 per 1000 patient-years. Most patients maintained minimal or no disability (mRS 0 or 1). Presenting with epilepsy at baseline significantly increased the odds of future seizures (OR 18.13, p = 0.001). CONCLUSION: This study highlights the complex presentation and progression of fCCMs, emphasizing the necessity for long-term monitoring. Baseline epilepsy is a significant predictor of future seizures, underscoring the need for individualized management strategies. Future research with larger cohorts and standardized criteria is essential to refine the understanding and management of fCCMs.

Circulating Blood Prognostic Biomarker Signatures for Hemorrhagic Cerebral Cavernous Malformations (CCMs).

Cerebral cavernous malformations (CCMs) are a neurological disorder characterized by enlarged intracranial capillaries in the brain, increasing the susceptibility to hemorrhagic strokes, a major cause of death and disability worldwide. The limited treatment options for CCMs underscore the importance of prognostic biomarkers to predict the likelihood of hemorrhagic events, aiding in treatment decisions and identifying potential pharmacological targets. This study aimed to identify blood biomarkers capable of diagnosing and predicting the risk of hemorrhage in CCM1 patients, establishing an initial set of circulating biomarker signatures. By analyzing proteomic profiles from both human and mouse CCM models and conducting pathway enrichment analyses, we compared groups to identify potential blood biomarkers with statistical significance. Specific candidate biomarkers primarily associated with metabolism and blood clotting pathways were identified. These biomarkers show promise as prognostic indicators for CCM1 deficiency and the risk of hemorrhagic stroke, strongly correlating with the likelihood of hemorrhagic cerebral cavernous malformations (CCMs). This lays the groundwork for further investigation into blood biomarkers to assess the risk of hemorrhagic CCMs.

Molecular and Cellular Characterization of Primary Endothelial Cells from a Familial Cavernomatosis Patient.

Cerebral cavernous malformation (CCM) or familial cavernomatosis is a rare, autosomal dominant, inherited disease characterized by the presence of vascular malformations consisting of blood vessels with an abnormal structure in the form of clusters. Based on the altered gene (CCM1/Krit1, CCM2, CCM3) and its origin (spontaneous or familial), different types of this disease can be found. In this work we have isolated and cultivated primary endothelial cells (ECs) from peripheral blood of a type 1 CCM patient. Differential functional and gene expression profiles of these cells were analyzed and compared to primary ECs from a healthy donor. The mutation of the familial index case consisted of a heterozygous point mutation in the position +1 splicing consensus between exons 15 and 16, causing failure in RNA processing and in the final protein. Furthermore, gene expression analysis by quantitative PCR revealed a decreased expression of genes involved in intercellular junction formation, angiogenesis, and vascular homeostasis. Cell biology analysis showed that CCM1 ECs were impaired in angiogenesis and cell migration. Taken together, the results obtained suggest that the alterations found in CCM1 ECs are already present in the heterozygous condition, suffering from vascular impairment and somewhat predisposed to vascular damage.

Endothelial hyperactivation of mutant MAP3K3 induces cerebral cavernous malformation enhanced by PIK3CA GOF mutation.

Cerebral cavernous malformations (CCMs) refer to a common vascular abnormality that affects up to 0.5% of the population. A somatic gain-of-function mutation in MAP3K3 (p.I441M) was recently reported in sporadic CCMs, frequently accompanied by somatic activating PIK3CA mutations in diseased endothelium. However, the molecular mechanisms of these driver genes remain elusive. In this study, we performed whole-exome sequencing and droplet digital polymerase chain reaction to analyze CCM lesions and the matched blood from sporadic patients. 44 of 94 cases harbored mutations in KRIT1/CCM2 or MAP3K3, of which 75% were accompanied by PIK3CA mutations (P = 0.006). AAV-BR1-mediated brain endothelial-specific MAP3K3I441M overexpression induced CCM-like lesions throughout the brain and spinal cord in adolescent mice. Interestingly, over half of lesions disappeared at adulthood. Single-cell RNA sequencing found significant enrichment of the apoptosis pathway in a subset of brain endothelial cells in MAP3K3I441M mice compared to controls. We then demonstrated that MAP3K3I441M overexpression activated p38 signaling that is associated with the apoptosis of endothelial cells in vitro and in vivo. In contrast, the mice simultaneously overexpressing PIK3CA and MAP3K3 mutations had an increased number of CCM-like lesions and maintained these lesions for a longer time compared to those with only MAP3K3I441M. Further in vitro and in vivo experiments showed that activating PI3K signaling increased proliferation and alleviated apoptosis of endothelial cells. By using AAV-BR1, we found that MAP3K3I441M mutation can provoke CCM-like lesions in mice and the activation of PI3K signaling significantly enhances and maintains these lesions, providing a preclinical model for the further mechanistic and therapeutic study of CCMs.

Discovery and Characterization of Ephrin B2 and EphB4 Dysregulation and Novel Mutations in Cerebral Cavernous Malformations: In Vitro and Patient-Derived Evidence of Ephrin-Mediated Endothelial Cell Pathophysiology.

Intracranial vascular malformations manifest on a continuum ranging from predominantly arterial to predominantly venous in pathology. Cerebral cavernous malformations (CCMs) are capillary malformations that exist at the midpoint of this continuum. The axon guidance factor Ephrin B2 and its receptor EphB4 are critical regulators of vasculogenesis in the developing central nervous system. Ephrin B2/EphB4 dysregulation has been implicated in the pathogenesis of arterial-derived arteriovenous malformations and vein-based vein of Galen malformations. Increasing evidence supports the hypothesis that aberrant Ephrin B2/EphB4 signaling may contribute to developing vascular malformations, but their role in CCMs remains largely uncharacterized. Evidence of Ephrin dysregulation in CCMs would be important to establish a common link in the pathogenic spectrum of EphrinB2/Ephb4 dysregulation. By studying patient-derived primary CCM endothelial cells (CCMECs), we established that CCMECs are functionally distinct from healthy endothelial cell controls; CCMECs demonstrated altered patterns of migration, motility, and impaired tube formation. In addition to the altered phenotype, the CCMECs also displayed an increased ratio of EphrinB2/EphB4 compared to the healthy endothelial control cells. Furthermore, whole exome sequencing identified mutations in both EphrinB2 and EphB4 in the CCMECs. These findings identify functional alterations in the EphrinB2/EphB4 ratio as a feature linking pathophysiology across the spectrum of arterial, capillary, and venous structural malformations in the central nervous system while revealing a putative therapeutic target.

Modifiable vascular risk factors in patients with cerebral and spinal cavernous malformations: a complete 10-year follow-up study.

BACKGROUND AND PURPOSE: The aim was to investigate the effect of modifiable vascular risk factors on the risk of first and recurrent bleeding for patients with a cavernous malformation (CM) of the central nervous system (CNS) over a 10-year period. METHODS: A retrospective review of our CM institutional database was performed spanning from 2003 to 2021. The inclusion criteria were non-missing serial magnetic resonance imaging studies and clinical baseline metrics such as vascular risk factors. The exclusion criteria were patients who underwent surgical CM removal and patients with less than a decade of follow-up. Kaplan-Meier and Cox regression analyses were performed to determine the cumulative risk (10 years) of hemorrhage. RESULTS: Eighty-nine patients with a CM of the CNS were included. Our results showed a non-significant increased risk of hemorrhage during 10 years of follow-up in patients using nicotine (hazard ratio 2.11, 95% confidence interval 0.86-5.21) and in patients with diabetes (hazard ratio 3.25, 95% confidence interval 0.71-14.81). For the presence of modifiable vascular risk factors at study baseline different cumulative 10-year risks of bleeding were observed: arterial hypertension 42.9% (18.8%-70.4%); diabetes 66.7% (12.5%-98.2%); hyperlipidemia 30% (8.1%-64.6%); active nicotine abuse 50% (24.1%-76%); and obesity 22.2% (4%-59.8%). Overall cumulative (10-year) hemorrhage risk was 30.3% (21.3%-41.1%). CONCLUSIONS: The probability of hemorrhage in untreated CNS CM patients increases progressively within a decade of follow-up. None of the modifiable vascular risk factors showed strong indication for an influence on hemorrhage risk, but our findings may suggest a more aggressive course in patients with active nicotine abuse or suffering from diabetes.

Central nervous system cavernous malformations: cross-sectional study assessing rebleeding risk after a second haemorrhage.

BACKGROUND AND PURPOSE: The purpose of this study was to investigate the 5-year risk of a third bleeding event in cavernous malformations (CMs) of the central nervous system. METHODS: Patients with cerebral or spinal CMs treated between 2003 and 2021 were screened using our institutional database. Patients with a complete magnetic resonance imaging dataset, clinical baseline characteristics, and history of two bleeding events were included. Patients who underwent surgical CM removal were excluded. Neurological functional status was obtained using the modified Rankin Scale score at the second and third bleeding. Kaplan-Meier and Cox regression analyses were performed to determine the cumulative 5-year risk for a third haemorrhage. RESULTS: Forty-two patients were included. Cox regression analysis adjusted for age and sex did not identify risk factors for a third haemorrhage. 37% of patients experienced neurological deterioration after the third haemorrhage (p = 0.019). The cumulative 5-year risk of a third bleeding was 66.7% (95% confidence interval [CI] 50.4%-80%) for the whole cohort, 65.9% (95% CI 49.3%-79.5%) for patients with bleeding at initial diagnosis, 72.7% (95% CI 39.3%-92.7%) for patients with a developmental venous anomaly, 76.9% (95% CI 55.9%-90.3%) for patients with CM localization to the brainstem and 75% (95% CI 50.6%-90.4%) for patients suffering from familial CM disease. CONCLUSIONS: During an untreated 5-year follow-up after a second haemorrhage, a significantly increased risk of a third haemorrhage compared to the known risk of a first and second bleeding event was identified. The third bleeding was significantly associated with neurological deterioration. These findings may justify a surgical treatment after a second bleeding event.

Impact of Long-Term Antithrombotic and Statin Therapy on the Clinical Outcome in Patients with Cavernous Malformations of the Central Nervous System: A Single-Center Case Series of 428 Patients.

INTRODUCTION: Literature regarding the safety and efficacy of antithrombotic (antiplatelet or anticoagulant) therapy and statins in patients with cavernous malformations (CMs) of the central nervous system is sparse, resulting in uncertainty about its use in clinical practice. The aim of this study was to analyze the impact of antithrombotic therapy and statins on the risk of hemorrhage and focal neurological deficit in patients with CMs. METHODS: The authors' institutional database was screened for all patients with CMs of the central nervous system treated at their institution between 2006 and 2018. Patients with radiological and/or histological diagnosis of CMs, clinical baseline characteristics, available patient's medication history, and follow-up data were included in this study. Time-to-event probability (hemorrhage or focal neurological deficit) as well as the number of events (hemorrhage or focal neurological deficit) during follow-up were assessed in patients who were categorized according to their medical treatment (antithrombotic therapy, statins, combined therapy, or no treatment). RESULTS: Four hundred twenty-eight patients with CMs were eligible and included in the final analysis. Sixty-nine (16.1%) patients were on long-term antithrombotic therapy and 46 (10.6%) on long-term statins, of whom 31 patients were on a combination of both. The probability of experiencing first hemorrhage or focal neurological deficit was less likely in patients on antiplatelet therapy (HR 0.09, 95% CI 0.021-0.39, p = 0.001), anticoagulant therapy (HR 0.12, 95% CI 0.016-0.85, p = 0.034), or the combination thereof (HR 0.12, 95% CI 0.016-0.93, p = 0.043) compared to patients with no antithrombotic treatment. The number of hemorrhages and focal neurological deficits were significantly lower in patients on antithrombotic therapy compared to patients on no treatment during follow-up. In patients on statins alone, the time-to-event probability was comparable to that of patients on no treatment (HR 0.91, 95% CI 0.438-1.91, p = 0.812), and the number of events was similar to patients on no treatment. CONCLUSION: The results of our study provide further evidence that antithrombotic therapy alone or in combination with statins in patients with CMs of the central nervous system does not increase the risk of hemorrhage or focal neurological deficit but, on the contrary, may have some benefit.

Inflammation and neutrophil extracellular traps in cerebral cavernous malformation.

Cerebral Cavernous Malformation (CCM) is a brain vascular disease with various neurological symptoms. In this study, we describe the inflammatory profile in CCM and show for the first time the formation of neutrophil extracellular traps (NETs) in rodents and humans with CCM. Through RNA-seq analysis of cerebellum endothelial cells from wild-type mice and mice with an endothelial cell-specific ablation of the Ccm3 gene (Ccm3iECKO), we show that endothelial cells from Ccm3iECKO mice have an increased expression of inflammation-related genes. These genes encode proinflammatory cytokines and chemokines, as well as adhesion molecules, which promote recruitment of inflammatory and immune cells. Similarly, immunoassays showed elevated levels of these cytokines and chemokines in the cerebellum of the Ccm3iECKO mice. Consistently, both flow cytometry and immunofluorescence analysis showed infiltration of different subsets of leukocytes into the CCM lesions. Neutrophils, which are known to fight against infection through different strategies, including the formation of NETs, represented the leukocyte subset within the most pronounced increase in CCM. Here, we detected elevated levels of NETs in the blood and the deposition of NETs in the cerebral cavernomas of Ccm3iECKO mice. Degradation of NETs by DNase I treatment improved the vascular barrier. The deposition of NETs in the cavernomas  of patients with CCM confirms the clinical relevance of NETs in CCM.

Contact-dependent signaling triggers tumor-like proliferation of CCM3 knockout endothelial cells in co-culture with wild-type cells.

Cerebral cavernous malformations (CCM) are low-flow vascular lesions prone to cause severe hemorrhage-associated neurological complications. Pathogenic germline variants in CCM1, CCM2, or CCM3 can be identified in nearly 100% of CCM patients with a positive family history. In line with the concept that tumor-like mechanisms are involved in CCM formation and growth, we here demonstrate an abnormally increased proliferation rate of CCM3-deficient endothelial cells in co-culture with wild-type cells and in mosaic human iPSC-derived vascular organoids. The observation that NSC59984, an anticancer drug, blocked the abnormal proliferation of mutant endothelial cells further supports this intriguing concept. Fluorescence-activated cell sorting and RNA sequencing revealed that co-culture induces upregulation of proangiogenic chemokine genes in wild-type endothelial cells. Furthermore, genes known to be significantly downregulated in CCM3-/- endothelial cell mono-cultures were upregulated back to normal levels in co-culture with wild-type cells. These results support the hypothesis that wild-type ECs facilitate the formation of a niche that promotes abnormal proliferation of mutant ECs. Thus, targeting the cancer-like features of CCMs is a promising new direction for drug development.

De novo cerebral cavernous malformations with PIK3CA somatic mutation and EPHB4 germline mutation in a child with multiple developmental venous anomalies and cutaneous vascular malformations.

Cavernous malformations (CM) that arise in the central nervous system have long been considered congenital, while there are many reports of de novo non-familial-type CM adjacent to developmental venous anomalies (DVA) or after radiation. The mechanisms that cause de novo formations of sporadic cavernous malformation (CM) still remain unknown and purely speculative. We report a case of de novo cerebral CM in a child with multiple developmental venous anomalies and cutaneous vascular malformations. Histological examination and whole-exome sequencing (WES) was performed on a fresh-frozen tissue sample of the CM. WES revealed 2 missense non-synonymous variants in two genes, EPHB4 and PIK3CA. The mutant allele of EPHB4 (NM_004444.4: c.1840 T > C, p.Y614H) appeared in 248/469 WES reads (allele frequency, 52.88%), which suggested the mutation a germline one. PIK3CA (NM_006218.2) somatic mutations were found in exon 9: c.1624G > A (p.Glu542Lys) with variant frequency of 2.2% (2/89 WES reads). We did not find any non-synonymous mutations of the three CCM genes (KRIT1, CCM2, and PDCD10) in this patient. Our findings suggested that the combination of gain of function in PIK3CA and loss of function in EPHB4 may play an important role in the pathogenesis of CM, which can develop in acquired form like tumorigenesis.

Concurrent high-grade glioma with cavernous malformations and pathogenic variants in PDCD10 and SMARCA4.

The co-occurrence of multiple disease processes can pose diagnostic challenges. We report an unusual case of a patient found to have co-occurrences of an IDH1-mutant high-grade glioma along with cerebral cavernous malformations and pathogenic germline variants in PDCD10 and SMARCA4. Somatic testing was done on the tumor and identified a SMARCA4 and two TP53 variants. Within the literature, little is known about the association of high-grade gliomas with these germline variants. Such findings furthermore not only inform complex diagnoses, but have the potential to play a crucial role in the ongoing care of a patient.

A 5-year outcome of propranolol for the treatment of paediatric intracranial cavernoma: case report and a review of the literature.

We describe a case of a young male patient with KRIT1-driven familial cavernous malformation syndrome who developed multiple brain cavernomas, intracranial bleeding, and persistent seizures. Due to the relentless growth of cavernous malformations and recurrent intracranial bleeds, it was decided to enrol the patient in the "Propranolol for Intracranial Cavernoma" (PICC) pilot trial at our institution. Over the 5-year treatment period with 20 to 40-mg oral propranolol three times daily (TDS), we noted the near-complete arrest of the growth of cavernous malformations with no further evidence of intracranial bleeding or any further seizures. The observed outcome is consistent with the extremely limited published literature on the topic; thus, this case provides important evidence that supports the use of propranolol as a prophylactic treatment for paediatric intracranial cavernomas. We strongly encourage and recommend future prospective randomised controlled trials to definitively assess and characterize the therapeutic utility of propranolol in this patient population.

Angioarchitecture and genetic variants of spinal cord cavernous malformations and associated developmental venous anomalies: a case report.

Cavernous malformations (CM) have long been considered congenital of central nervous system, while the mechanism of CMs detailed development process associated with genetic factors remains unclear. We reported an uncommon case which suffered spinal cord cavernous malformations. In this work, representative samples were obtained, and the sequenced results were described for the first time. A 9-year-old boy was found oblique shoulder with slightly weakness of left limbs; MRI indicated spinal cord cavernous malformations (CMs) located at the C4-C6 vertebral level. On genetic analysis, a shared mutation of PIK3CA (p.H1047R) in CMs and associated developmental venous anomalies (DVAs) was detected, with a different abundance (2% and 7%, respectively), and a somatic mutation of MAP3K3 (p.I441M) was detected in the CM tissue samples. This case provides better knowledge of the formation history and genetic triggers of the DVA-associated CMs. This evidence allows us to speculate the developmental history of the CM lesion: The DVA with PIK3CA mutation might be genetic precursor, and then the associated CM could be derived from terminal cell population of the DVA by acquiring a somatic mutation in MAP3K3.

Functional neurological outcome of spinal cavernous malformation surgery.

PURPOSE: Spinal cavernous malformations (SCM) present a risk for intramedullary hemorrhage (IMH), which can cause severe neurologic deficits. Patient selection and time of surgery have not been clearly defined. METHODS: This observational study included SCM patients who underwent surgery in our department between 2003 and 2021. Inclusion required baseline clinical factors, magnetic resonance imaging studies, and follow-up examination. Functional outcome was assessed using the Modified McCormick scale score. RESULTS: Thirty-five patients met the inclusion criteria. The mean age was 44.7 ± 14.5 years, and 60% of the patients were male. In univariate analysis, the unfavorable outcome was significantly associated with multiple bleeding events (p = .031), ventral location of the SCM (p = .046), and incomplete resection (p = .028). The time between IMH and surgery correlated with postoperative outcomes (p = .004), and early surgery within 3 months from IMH was associated with favorable outcomes (p = .033). This association remained significant in multivariate logistic regression analysis (p = .041). CONCLUSIONS: Removal of symptomatic SCM should be performed within 3 months after IMH when gross total resection is feasible. Patients with ventrally located lesions might be at increased risk for postoperative deficits.