Multiple cerebral cavernous malformations associated with extracranial mesenchymal anomalies

CCM3 Loss-Induced Lymphatic Defect Is Mediated by the Augmented VEGFR3-ERK1/2 Signaling

OBJECTIVE

Cerebral cavernous malformations (CCMs) can happen anywhere in the body, although they most commonly produce symptoms in the brain. The role of CCM genes in other vascular beds outside the brain and retina is not well-examined, although the 3 CCM-associated genes (CCM1, CCM2, and CCM3) are ubiquitously expressed in all tissues. We aimed to determine the role of CCM gene in lymphatics. Approach and Results: Mice with an inducible pan-endothelial cell (EC) or lymphatic EC deletion of Ccm3 (Pdcd10ECKO or Pdcd10LECKO) exhibit dilated lymphatic capillaries and collecting vessels with abnormal valve structure. Morphological alterations were correlated with lymphatic dysfunction in Pdcd10LECKO mice as determined by Evans blue dye and fluorescein isothiocyanate(FITC)-dextran transport assays. Pdcd10LECKO lymphatics had increased VEGFR3 (vascular endothelial growth factor receptor-3)-ERK1/2 (extracellular signal-regulated kinase 1/2) signaling with lymphatic hyperplasia. Mechanistic studies suggested that VEGFR3 is primarily regulated at a transcriptional level in Ccm3-deficient lymphatic ECs, in an NF-κB (nuclear factor κB)-dependent manner. CCM3 binds to importin alpha 2/KPNA2 (karyopherin subunit alpha 2), and a CCM3 deletion releases KPNA2 to activate NF-κB P65 by facilitating its nuclear translocation and P65-dependent VEGFR3 transcription. Moreover, increased VEGFR3 in lymphatic EC preferentially activates ERK1/2 signaling, which is critical for lymphatic EC proliferation. Importantly, inhibition of VEGFR3 or ERK1/2 rescued the lymphatic defects in structure and function.

CONCLUSIONS

Our data demonstrate that CCM3 deletion augments the VEGFR3-ERK1/2 signaling in lymphatic EC that drives lymphatic hyperplasia and malformation and warrant further investigation on the potential clinical relevance of lymphatic dysfunction in patients with CCM.

Children with cavernous malformations of the central nervous system

BACKGROUND

Cavernous malformations (CM) of the central nervous system (CNS) are a rare pathology in the pediatric population that may present with an acute onset of severe neurological symptoms.

OBJECTIVE

The aim of our study was to evaluate the clinical presentation, family history, genetic background, radiological features, treatment and outcome of children with CM.

METHODS

This observational cohort study included all children with CM of the CNS diagnosed in the period 2000-2020 at University Children's Hospital in Ljubljana, Slovenia. Whole exome sequencing was utilized.

RESULTS

We identified a cohort of 20 children with CM (mean age 9.3 years, range: 10 days-18.4 years). In our cohort, 16 patients were symptomatic and 4 were asymptomatic; 7 patients had a solitary lesion, and 13 had multiple lesions. Children with multiple lesions become symptomatic at an earlier age compared with children with solitary lesions. We identified five families with familiar cavernous malformation (FCM) syndrome affecting two or more generations; FCM represented 65% of all pediatric cases identified in our study. We confirmed a mutation in FCM associated genes in all but one patient with multiple lesions, with the KRIT1 mutation being the most common.

CONCLUSION

Multiple CM lesions and symptomatic brainstem lesions are associated with worse neurological deficits in pediatric patients. Not all cases of multiple lesions can be linked to mutations in KRIT1, CCM2, or PDCD10, which may indicate that there are other as yet unidentified genes associated with FCM.

Case Report: Giant Biatrial Myxoma Mimicking Malignant Cardiac Tumor in a Patient With a Hepatic Angiomatous Mass

Cardiac myxomas, primarily originating from the left atrium, are the most prevalent types of benign cardiac tumors; however, biatrial myxomas are extremely rare. Herein, we present a rare case of a 55-year old male with exertional dyspnea and intermittent chest discomfort due to a giant biatrial mass with concomitant atrial fibrillation and hepatic hemangioma. The giant tumor with its peduncle at the interatrial septum involved both atria; however, bulging through the tricuspid valve to the right ventricle during systole. Hence, excision of the giant cardiac tumor (which grossly composed of three parts: stiff, fleshy, and soft) and Cox-Maze IV procedure was performed with the resected specimen measuring 100 × 80 × 40 mm. The patient who was in a stable condition was discharged home on the 12th post-operative day. Thus, given the excellent post-operative results achieved, surgical treatment in large multi-cavitary benign cardiac tumors is feasible and should be considered a potentially curative therapy.

Giant intrahepatic venous malformation with localized intravascular coagulopathy. Follow-up and treatment during pregnancy

Intrahepatic lesions in adults, commonly named hepatic hemangioma, should be called Intrahepatic Venous Malformations (IHVM), or Giant Intrahepatic Venous Malformations (GIHVM) when larger than 10 cm according to the ISSVA classification (International society study group for vascular anomalies). Localized coagulation disorders (LIC) in patients with venous malformations are quite commonly associated in venous malformations, they result in decreased fibrinogen (< 2g/l) and elevated d-dimers (> 1500 ng/ml) and might be responsible of intralesional thrombotic, pain or bleeding episodes.We report a case report of a 41 y/o patient that presented with right hypochondrium pain episodes discovering an unknown GIHVM on ultrasound imaging with a prior history of uterine bleeding episodes and multiples miscarriages.On laboratory work up the patient presented an associated localized Intravascular Coagulation (LIC) with the GIHVM. As the patient desire to become pregnant was important our multidisciplinary clinic allowed a pregnancy with close clinical, biological and imaging monitoring and follow up. Early initiation of low molecular weighted heparin (LMWH) successfully allowed an uncomplicated term pregnancy and delivery. Intrahepatic lesion stability was achieved and prevented progression from LIC to diffuse intravascular coagulation disorder (DIC)..

Hereditary Multiple Cerebral Cavernous Malformations Associated with Wilson Disease and Multiple Lipomatosis

We report on a patient with 2 Mendelian diseases-symptomatic multiple familial cerebral cavernous malformations (FCCMs) and Wilson disease. Genetic analysis revealed single nucleotide polymorphisms in genes CCM2 and CCM3, associated with cavernous malformations, and homozygote mutation in the ATP7B gene, responsible for Wilson disease. FCCMs were symptomatic in 3 generations. The patient also had multiple lipomatosis, which is suggested to be a familial syndrome. In recent years there has been an increasing amount of publications linking FCCMs with other pathology, predominantly with extracranial and intracranial mesenchymal anomalies. The present study is the description of an unusual association between 2 independent hereditary diseases of confirmed genetic origin-a combination that has not been described previously.

Focal cortical dysplasia type IIIc associates with multiple cerebral cavernomas

The distinction of isolated malformations and combined lesions constitutes a major novelty in the 2011 consensus classification of the International League against Epilepsy (ILAE) for focal cortical dysplasias (FCD). Cortical lamination abnormalities together with vascular lesions are subsumed as FCD IIIc. Little is known regarding frequency and etiology of this entity. Here, we systematically evaluated biopsy specimens from 72 drug-refractory epilepsy patients with cerebral cavernous malformations (CCM) regarding presence of associated FCD. Due to a non-perpendicular orientation of the cortical structures or absence of sufficient cortical tissue adjacent to the vascular lesion 25 samples were not classifiable. In the remaining 47 cases FCD IIIc was rare (4.3%), but significantly increased in patients with multiple CCM (28.6%; p<0.05 vs. single CCM). Association of FCD IIIc with multiple CCM may argue against FCD IIIc as an acquired lesion.

Cerebral cavernous malformations proteins inhibit Rho kinase to stabilize vascular integrity

Endothelial cell–cell junctions regulate vascular permeability, vasculogenesis, and angiogenesis. Familial cerebral cavernous malformations (CCMs) in humans result from mutations of CCM2 (malcavernin, OSM, MGC4607), PDCD10 (CCM3), or KRIT1 (CCM1), a Rap1 effector which stabilizes endothelial cell–cell junctions. Homozygous loss of KRIT1 or CCM2 produces lethal vascular phenotypes in mice and zebrafish. We report that the physical interaction of KRIT1 and CCM2 proteins is required for endothelial cell–cell junctional localization, and lack of either protein destabilizes barrier function by sustaining activity of RhoA and its effector Rho kinase (ROCK). Protein haploinsufficient Krit1^+/− or Ccm2^+/− mouse endothelial cells manifested increased monolayer permeability in vitro, and both Krit1^+/− and Ccm2^+/− mice exhibited increased vascular leak in vivo, reversible by fasudil, a ROCK inhibitor. Furthermore, we show that ROCK hyperactivity occurs in sporadic and familial human CCM endothelium as judged by increased phosphorylation of myosin light chain. These data establish that KRIT1–CCM2 interaction regulates vascular barrier function by suppressing Rho/ROCK signaling and that this pathway is dysregulated in human CCM endothelium, and they suggest that fasudil could ameliorate both CCM disease and vascular leak.