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Genetics and Vascular Biology of Brain Vascular Malformations. Stroke 2022. [DOI: 10.1016/b978-0-323-69424-7.00012-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Mahendra Y, He M, Rouf MA, Tjakra M, Fan L, Wang Y, Wang G. Progress and prospects of mechanotransducers in shear stress-sensitive signaling pathways in association with arteriovenous malformation. Clin Biomech (Bristol, Avon) 2021; 88:105417. [PMID: 34246943 DOI: 10.1016/j.clinbiomech.2021.105417] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Revised: 06/21/2021] [Accepted: 06/21/2021] [Indexed: 02/07/2023]
Abstract
Arteriovenous malformations are congenital vascular lesions characterized by a direct and tangled connection between arteries and veins, which disrupts oxygen circulation and normal blood flow. Arteriovenous malformations often occur in the patient with hereditary hemorrhagic telangiectasia. The attempts to elucidate the causative factors and pathogenic mechanisms of arteriovenous malformations are now still in progress. Some studies reported that shear stress in blood flow is one of the factors involved in arteriovenous malformations manifestation. Through several mechanotransducers harboring the endothelial cells membrane, the signal from shear stress is transduced towards the responsible signaling pathways in endothelial cells to maintain cell homeostasis. Any disruption in this well-established communication will give rise to abnormal endothelial cells differentiation and specification, which will later promote arteriovenous malformations. In this review, we discuss the update of several mechanotransducers that have essential roles in shear stress-induced signaling pathways, such as activin receptor-like kinase 1, Endoglin, Notch, vascular endothelial growth factor receptor 2, Caveolin-1, Connexin37, and Connexin40. Any disruption of these signaling potentially causes arteriovenous malformations. We also present some recent insights into the fundamental analysis, which attempts to determine potential and alternative solutions to battle arteriovenous malformations, especially in a less invasive and risky way, such as gene treatments.
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Affiliation(s)
- Yoga Mahendra
- Key Laboratory for Biorheological Science and Technology of Ministry of Education State and Local Joint Engineering Laboratory for Vascular Implants Bioengineering College of Chongqing University, Chongqing 400030, China
| | - Mei He
- Chongqing University Cancer Hospital, Chongqing Cancer Institute, Chongqing Cancer Hospital, Chongqing, China
| | - Muhammad Abdul Rouf
- Key Laboratory for Biorheological Science and Technology of Ministry of Education State and Local Joint Engineering Laboratory for Vascular Implants Bioengineering College of Chongqing University, Chongqing 400030, China
| | - Marco Tjakra
- Key Laboratory for Biorheological Science and Technology of Ministry of Education State and Local Joint Engineering Laboratory for Vascular Implants Bioengineering College of Chongqing University, Chongqing 400030, China
| | - Longling Fan
- Key Laboratory for Biorheological Science and Technology of Ministry of Education State and Local Joint Engineering Laboratory for Vascular Implants Bioengineering College of Chongqing University, Chongqing 400030, China
| | - Yeqi Wang
- Key Laboratory for Biorheological Science and Technology of Ministry of Education State and Local Joint Engineering Laboratory for Vascular Implants Bioengineering College of Chongqing University, Chongqing 400030, China.
| | - Guixue Wang
- Key Laboratory for Biorheological Science and Technology of Ministry of Education State and Local Joint Engineering Laboratory for Vascular Implants Bioengineering College of Chongqing University, Chongqing 400030, China.
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Haubner F, Schneider A, Schinke H, Bertlich M, Weiss BG, Canis M, Kashani F. Classification of endonasal HHT lesions using digital microscopy. Orphanet J Rare Dis 2021; 16:182. [PMID: 33865423 PMCID: PMC8053266 DOI: 10.1186/s13023-021-01801-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Accepted: 03/30/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Recurrent spontaneous epistaxis is the most common clinical manifestation and the most debilitating symptom in hereditary haemorrhagic telangiectasia (HHT) patients. To this date, there exist only a classification of HHT patients by different genetic mutations. There is no standard classification for the mucocutaneous endonasal manifestations of HHT. The aim of the present study was to document the variety of endonasal HHT lesions using digital microscopy and to propose a clinical classification. METHODS We recorded the endonasal HHT lesions of 28 patients using a digital microscope. We reconstructed the 3D images und videos recorded by digital microscope afterwards and classified the endonasal lesions of HHT in two classes: Grade A, presence of only flat telangiectasias in the mucosa level and Grade B, (additional) presence of raised berry or wart-like telangiectasia spots. We investigated also Haemoglobin level by routine laboratory procedures, plasma VEGF level by ELISA, Severity of epistaxis by epistaxis severity score (ESS) and quality of life by a linear visual analogue scale (VAS). RESULTS We found a higher quality of life and a lower severity of epistaxis in Grade A patients in comparison to Grade B patients. No difference in plasma VEGF level and in Haemoglobin between Grad A patients and Grade B patients could be detected. Plasma VEGF levels showed no gender specific differences. It could also not be correlated to the extranasal manifestation. CONCLUSION The classification for endonasal manifestation of HHT proposed in this study indicates severity of epistaxis und quality of life. Digital microscopy with the ability of 3D reconstruction of images presents a useful tool for such classifications. The classification of endonasal HHT lesions using digital microscopy allows to evaluate the dynamic of HHT lesions in the course of time independent of examiner. This allows also to evaluate the efficacy of the different treatment modalities by dynamic of HHT lesions. Moreover digital microscopy is very beneficial in academic teaching of rare diseases.
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Affiliation(s)
- F Haubner
- Department of Otorhinolaryngology, Head and Neck Surgery, University Hospital, LMU Munich, Marchioninistrasse 15, 81377, Munich, Germany.
| | | | - H Schinke
- Department of Otorhinolaryngology, Head and Neck Surgery, University Hospital, LMU Munich, Marchioninistrasse 15, 81377, Munich, Germany
| | - M Bertlich
- Department of Otorhinolaryngology, Head and Neck Surgery, University Hospital, LMU Munich, Marchioninistrasse 15, 81377, Munich, Germany
| | - B G Weiss
- Department of Otorhinolaryngology, Head and Neck Surgery, University Hospital, LMU Munich, Marchioninistrasse 15, 81377, Munich, Germany
| | - M Canis
- Department of Otorhinolaryngology, Head and Neck Surgery, University Hospital, LMU Munich, Marchioninistrasse 15, 81377, Munich, Germany
| | - F Kashani
- Department of Otorhinolaryngology, Head and Neck Surgery, University Hospital, LMU Munich, Marchioninistrasse 15, 81377, Munich, Germany
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Giarretta I, Sturiale CL, Gatto I, Pacioni S, Gaetani E, Porfidia A, Puca A, Palucci I, Tondi P, Olivi A, Pallini R, Pola R. Sonic hedgehog is expressed in human brain arteriovenous malformations and induces arteriovenous malformations in vivo. J Cereb Blood Flow Metab 2021; 41:324-335. [PMID: 32169015 PMCID: PMC8369994 DOI: 10.1177/0271678x20912405] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Abnormalities in arterial versus venous endothelial cell identity and dysregulation of angiogenesis are deemed important in the pathophysiology of brain arteriovenous malformations (AVMs). The Sonic hedgehog (Shh) pathway is crucial for both angiogenesis and arterial versus venous differentiation of endothelial cells, through its dual role on the vascular endothelial growth factor/Notch signaling and the nuclear orphan receptor COUP-TFII. In this study, we show that Shh, Gli1 (the main transcription factor of the Shh pathway), and COUP-TFII (a target of the non-canonical Shh pathway) are aberrantly expressed in human brain AVMs. We also show that implantation of pellets containing Shh in the cornea of Efnb2/LacZ mice induces growth of distinct arteries and veins, interconnected by complex sets of arteriovenous shunts, without an interposed capillary bed, as seen in AVMs. We also demonstrate that injection in the rat brain of a plasmid containing the human Shh gene induces the growth of tangles of tortuous and dilated vessels, in part positive and in part negative for the arterial marker αSMA, with direct connections between αSMA-positive and -negative vessels. In summary, we show that the Shh pathway is active in human brain AVMs and that Shh-induced angiogenesis has characteristics reminiscent of those seen in AVMs in humans.
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Affiliation(s)
- Igor Giarretta
- Department of Medicine, Fondazione Policlinico Universitario A. Gemelli IRCCS, Università Cattolica del Sacro Cuore, Rome, Italy
| | - Carmelo L Sturiale
- Division of Neurosurgery, Fondazione Policlinico Universitario A. Gemelli IRCCS, Università Cattolica del Sacro Cuore, Rome, Italy
| | - Ilaria Gatto
- Department of Medicine, Fondazione Policlinico Universitario A. Gemelli IRCCS, Università Cattolica del Sacro Cuore, Rome, Italy
| | - Simone Pacioni
- Division of Neurosurgery, Fondazione Policlinico Universitario A. Gemelli IRCCS, Università Cattolica del Sacro Cuore, Rome, Italy
| | - Eleonora Gaetani
- Department of Medicine, Fondazione Policlinico Universitario A. Gemelli IRCCS, Università Cattolica del Sacro Cuore, Rome, Italy
| | - Angelo Porfidia
- Department of Medicine, Fondazione Policlinico Universitario A. Gemelli IRCCS, Università Cattolica del Sacro Cuore, Rome, Italy
| | - Alfredo Puca
- Division of Neurosurgery, Fondazione Policlinico Universitario A. Gemelli IRCCS, Università Cattolica del Sacro Cuore, Rome, Italy
| | - Ivana Palucci
- Istitute of Microbiology, Fondazione Policlinico Universitario A. Gemelli IRCCS, Università Cattolica del Sacro Cuore, Rome, Italy
| | - Paolo Tondi
- Department of Medicine, Fondazione Policlinico Universitario A. Gemelli IRCCS, Università Cattolica del Sacro Cuore, Rome, Italy
| | - Alessandro Olivi
- Division of Neurosurgery, Fondazione Policlinico Universitario A. Gemelli IRCCS, Università Cattolica del Sacro Cuore, Rome, Italy
| | - Roberto Pallini
- Division of Neurosurgery, Fondazione Policlinico Universitario A. Gemelli IRCCS, Università Cattolica del Sacro Cuore, Rome, Italy
| | - Roberto Pola
- Department of Medicine, Fondazione Policlinico Universitario A. Gemelli IRCCS, Università Cattolica del Sacro Cuore, Rome, Italy.,Division of Cardiovascular Research, St. Elizabeth's Medical Center, Boston, MA, USA
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Treatment with Atorvastatin During Vascular Remodeling Promotes Pericyte-Mediated Blood-Brain Barrier Maturation Following Ischemic Stroke. Transl Stroke Res 2021; 12:905-922. [PMID: 33423214 DOI: 10.1007/s12975-020-00883-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Revised: 12/21/2020] [Accepted: 12/22/2020] [Indexed: 10/22/2022]
Abstract
We previously showed that newly formed vessels in ischemic rat brain have high blood-brain barrier (BBB) permeability at 3 weeks after stroke due to a lack of major endothelial tight junction proteins (TJPs), which may exacerbate edema in stroke patients. Atorvastatin was suggested a dose-dependent pro-angiogenic effect and ameliorating BBB permeability beyond its cholesterol-lowering effects. This study examined our hypothesis that, during vascular remodeling after stroke, treatment with atorvastatin could facilitate BBB maturation in remodeling vasculature in ischemic brain. Adult spontaneously hypertensive rats underwent middle cerebral artery occlusion with reperfusion (MCAO/RP). Atorvastatin, at dose of 3 mg/kg, was delivered daily starting at 14 days after MCAO/RP onset for 7 days. The rats were studied at multiple time points up to 8 weeks with multimodal-MRI, behavior tests, immunohistochemistry, and biochemistry. The delayed treatment of atorvastatin significantly reduced infarct size and BBB permeability, restored cerebral blood flow, and improved the neurological outcome at 8 weeks after MCAO/RP. Postmortem studies showed that atorvastatin promoted angiogenesis and stabilized the newly formed vessels in peri-infarct areas. Importantly, atorvastatin facilitated maturation of BBB properties in the new vessels by promoting endothelial tight junction (TJ) formation. Further in vivo and in vitro studies demonstrated that proliferating peri-vascular pericytes expressing neural-glial antigen 2 (NG2) mediated the role of atorvastatin on BBB maturation through regulating endothelial TJ strand formations. Our results suggested a therapeutic potential of atorvastatin in facilitating a full BBB integrity and functional stroke recovery, and an essential role for pericyte-mediated endothelial TJ formation in remodeling vasculature.
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Krithika S, Sumi S. Neurovascular inflammation in the pathogenesis of brain arteriovenous malformations. J Cell Physiol 2020; 236:4841-4856. [PMID: 33345330 DOI: 10.1002/jcp.30226] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Revised: 11/11/2020] [Accepted: 12/08/2020] [Indexed: 11/11/2022]
Abstract
Brain arteriovenous malformations (bAVM) arise as congenital or sporadic focal lesions with a significant risk for intracerebral hemorrhage (ICH). A wide range of interindividual differences is present in the onset, progression, and severity of bAVM. A growing body of gene expression and polymorphism-based research studies support the involvement of localized inflammation in bAVM disease progression and rupture. In this review article, we analyze the altered responses of neural, vascular, and immune cell types that contribute to the inflammatory process, which exacerbates the pathophysiological progression of vascular dysmorphogenesis in bAVM lesions. The cumulative effect of inflammation in bAVM development is orchestrated by various genetic moderators and inflammatory mediators. We also discuss the potential therapies for the treatment of brain AVM by targeting the inflammatory processes and mediators. Elucidating the precise role of inflammation in the bAVM growth and hemorrhage would open novel avenues for noninvasive and effectual causal therapy that may complement the current therapeutic strategies.
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Affiliation(s)
- S Krithika
- Cardiovascular Diseases and Diabetes Biology, Rajiv Gandhi Centre for Biotechnology, Thiruvananthapuram, Kerala, India
| | - S Sumi
- Cardiovascular Diseases and Diabetes Biology, Rajiv Gandhi Centre for Biotechnology, Thiruvananthapuram, Kerala, India
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Cheng P, Ma L, Shaligram S, Walker EJ, Yang ST, Tang C, Zhu W, Zhan L, Li Q, Zhu X, Lawton MT, Su H. Effect of elevation of vascular endothelial growth factor level on exacerbation of hemorrhage in mouse brain arteriovenous malformation. J Neurosurg 2020; 132:1566-1573. [PMID: 31026826 PMCID: PMC6817409 DOI: 10.3171/2019.1.jns183112] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Accepted: 01/18/2019] [Indexed: 11/06/2022]
Abstract
OBJECTIVE A high level of vascular endothelial growth factor (VEGF) has been implicated in brain arteriovenous malformation (bAVM) bleeding and rupture. However, direct evidence is missing. In this study the authors used a mouse bAVM model to test the hypothesis that elevation of focal VEGF levels in bAVMs exacerbates the severity of bAVM hemorrhage. METHODS Brain AVMs were induced in adult mice in which activin receptor-like kinase 1 (Alk1, a gene that causes AVM) gene exons 4-6 were floxed by intrabasal ganglia injection of an adenoviral vector expressing Cre recombinase to induce Alk1 mutation and an adeno-associated viral vector expressing human VEGF (AAV-VEGF) to induce angiogenesis. Two doses of AAV-VEGF (5 × 109 [high] or 2 × 109 [low]) viral genomes were used. In addition, the common carotid artery and external jugular vein were anastomosed in a group of mice treated with low-dose AAV-VEGF 6 weeks after the model induction to induce cerebral venous hypertension (VH), because VH increases the VEGF level in the brain. Brain samples were collected 8 weeks after the model induction. Hemorrhages in the bAVM lesions were quantified on brain sections stained with Prussian blue, which detects iron deposition. VEGF levels were quantified in bAVM tissue by enzyme-linked immunosorbent assay. RESULTS Compared to mice injected with a low dose of AAV-VEGF, the mice injected with a high dose had higher levels of VEGF (p = 0.003) and larger Prussian blue-positive areas in the bAVM lesion at 8 or 9 weeks after model induction (p = 0.002). VH increased bAVM hemorrhage in the low-dose AAV-VEGF group. The overall mortality in the high-dose AAV-VEGF group was 26.7%, whereas no mouse died in the low-dose AAV-VEGF group without VH. In contrast, VH caused a mortality of 50% in the low-dose AAV-VEGF group. CONCLUSIONS Using mouse bAVM models, the authors provided direct evidence that elevation of the VEGF level increases bAVM hemorrhage and mouse mortality.
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Affiliation(s)
- Philip Cheng
- Department of Anesthesia and Perioperative Care, Center for Cerebrovascular Research, University of California, San Francisco, California
| | - Li Ma
- Department of Anesthesia and Perioperative Care, Center for Cerebrovascular Research, University of California, San Francisco, California
- Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, People’s Republic of China
| | - Sonali Shaligram
- Department of Anesthesia and Perioperative Care, Center for Cerebrovascular Research, University of California, San Francisco, California
| | - Espen J. Walker
- Department of Anesthesia and Perioperative Care, Center for Cerebrovascular Research, University of California, San Francisco, California
| | - Shun-Tai Yang
- Department of Anesthesia and Perioperative Care, Center for Cerebrovascular Research, University of California, San Francisco, California
| | - Chaoliang Tang
- Department of Anesthesia and Perioperative Care, Center for Cerebrovascular Research, University of California, San Francisco, California
| | - Wan Zhu
- Department of Anesthesia and Perioperative Care, Center for Cerebrovascular Research, University of California, San Francisco, California
| | - Lei Zhan
- Department of Anesthesia and Perioperative Care, Center for Cerebrovascular Research, University of California, San Francisco, California
| | - Qiang Li
- Department of Anesthesia and Perioperative Care, Center for Cerebrovascular Research, University of California, San Francisco, California
- Department of Neurological Surgery, University of California, San Francisco, California
| | - Xiaonan Zhu
- Department of Anesthesia and Perioperative Care, Center for Cerebrovascular Research, University of California, San Francisco, California
| | - Michael T. Lawton
- Department of Neurological Surgery, University of California, San Francisco, California
| | - Hua Su
- Department of Anesthesia and Perioperative Care, Center for Cerebrovascular Research, University of California, San Francisco, California
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Robert F, Desroches-Castan A, Bailly S, Dupuis-Girod S, Feige JJ. Future treatments for hereditary hemorrhagic telangiectasia. Orphanet J Rare Dis 2020; 15:4. [PMID: 31910860 PMCID: PMC6945546 DOI: 10.1186/s13023-019-1281-4] [Citation(s) in RCA: 56] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Accepted: 12/16/2019] [Indexed: 12/11/2022] Open
Abstract
Hereditary Hemorrhagic Telangiectasia (HHT), also known as Rendu-Osler syndrome, is a genetic vascular disorder affecting 1 in 5000–8000 individuals worldwide. This rare disease is characterized by various vascular defects including epistaxis, blood vessel dilations (telangiectasia) and arteriovenous malformations (AVM) in several organs. About 90% of the cases are associated with heterozygous mutations of ACVRL1 or ENG genes, that respectively encode a bone morphogenetic protein receptor (activin receptor-like kinase 1, ALK1) and a co-receptor named endoglin. Less frequent mutations found in the remaining 10% of patients also affect the gene SMAD4 which is part of the transcriptional complex directly activated by this pathway. Presently, the therapeutic treatments for HHT are intended to reduce the symptoms of the disease. However, recent progress has been made using drugs that target VEGF (vascular endothelial growth factor) and the angiogenic pathway with the use of bevacizumab (anti-VEGF antibody). Furthermore, several exciting high-throughput screenings and preclinical studies have identified new molecular targets directly related to the signaling pathways affected in the disease. These include FKBP12, PI3-kinase and angiopoietin-2. This review aims at reporting these recent developments that should soon allow a better care of HHT patients.
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Affiliation(s)
- Florian Robert
- Univ. Grenoble Alpes, Inserm, CEA, Laboratory Biology of Cancer and Infection, F-38000, Grenoble, France
| | - Agnès Desroches-Castan
- Univ. Grenoble Alpes, Inserm, CEA, Laboratory Biology of Cancer and Infection, F-38000, Grenoble, France
| | - Sabine Bailly
- Univ. Grenoble Alpes, Inserm, CEA, Laboratory Biology of Cancer and Infection, F-38000, Grenoble, France
| | - Sophie Dupuis-Girod
- Univ. Grenoble Alpes, Inserm, CEA, Laboratory Biology of Cancer and Infection, F-38000, Grenoble, France.,Hospices Civils de Lyon, Service de Génétique, Hôpital Femme-Mère-Enfants, F-69677, Bron, France.,Centre National de Référence pour la Maladie de Rendu-Osler, F-69677, Bron, France
| | - Jean-Jacques Feige
- Univ. Grenoble Alpes, Inserm, CEA, Laboratory Biology of Cancer and Infection, F-38000, Grenoble, France.
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Brinjikji W, Iyer VN, Yamaki V, Lanzino G, Cloft HJ, Thielen KR, Swanson KL, Wood CP. Neurovascular Manifestations of Hereditary Hemorrhagic Telangiectasia: A Consecutive Series of 376 Patients during 15 Years. AJNR Am J Neuroradiol 2016; 37:1479-86. [PMID: 27012295 DOI: 10.3174/ajnr.a4762] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Accepted: 01/28/2016] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE Hereditary hemorrhagic telangiectasia is associated with a wide range of neurovascular abnormalities. The aim of this study was to characterize the spectrum of cerebrovascular lesions, including brain arteriovenous malformations, in patients with hereditary hemorrhagic telangiectasia and to study associations between brain arteriovenous malformations and demographic variables, genetic mutations, and the presence of AVMs in other organs. MATERIALS AND METHODS Consecutive patients with definite hereditary hemorrhagic telangiectasia who underwent brain MR imaging/MRA, CTA, or DSA at our institution from 2001 to 2015 were included. All studies were re-evaluated by 2 senior neuroradiologists for the presence, characteristics, location, and number of brain arteriovenous malformations, intracranial aneurysms, and nonshunting lesions. Brain arteriovenous malformations were categorized as high-flow pial fistulas, nidus-type brain AVMs, and capillary vascular malformations and were assigned a Spetzler-Martin score. We examined the association between baseline clinical and genetic mutational status and the presence/multiplicity of brain arteriovenous malformations. RESULTS Three hundred seventy-six patients with definite hereditary hemorrhagic telangiectasia were included. One hundred ten brain arteriovenous malformations were noted in 48 patients (12.8%), with multiple brain arteriovenous malformations in 26 patients. These included 51 nidal brain arteriovenous malformations (46.4%), 58 capillary vascular malformations (52.7%), and 1 pial arteriovenous fistula (0.9%). Five patients (10.4%) with single nidal brain arteriovenous malformation presented with hemorrhage. Of brain arteriovenous malformations, 88.9% (88/99) had a Spetzler-Martin score of ≤2. Patients with brain arteriovenous malformations were more likely to be female (75.0% versus 57.6%, P = .01) and have a family history of hereditary hemorrhagic telangiectasia (95.8% versus 84.8%, P = .04). The prevalence of brain arteriovenous malformation was 19.7% in endoglin (ENG) mutations and 12.5% in activin receptor-like kinase (1ACVRL1) mutations. CONCLUSIONS Our study of 376 patients with hereditary hemorrhagic telangiectasia demonstrated a high prevalence of brain arteriovenous malformations. Nidal brain arteriovenous malformations and capillary vascular malformations occurred in roughly equal numbers.
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Affiliation(s)
- W Brinjikji
- From the Departments of Radiology (W.B., H.J.C., K.R.T., C.P.W.)
| | - V N Iyer
- Pulmonary and Critical Care Medicine (V.N.I., V.Y.)
| | - V Yamaki
- Pulmonary and Critical Care Medicine (V.N.I., V.Y.)
| | - G Lanzino
- Neurosurgery (G.L.), Mayo Clinic, Rochester, Minnesota
| | - H J Cloft
- From the Departments of Radiology (W.B., H.J.C., K.R.T., C.P.W.)
| | - K R Thielen
- From the Departments of Radiology (W.B., H.J.C., K.R.T., C.P.W.)
| | - K L Swanson
- Department of Pulmonary and Critical Care Medicine (K.L.S.), Mayo Clinic, Scottsdale, Arizona
| | - C P Wood
- From the Departments of Radiology (W.B., H.J.C., K.R.T., C.P.W.)
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Integrin β8 Deletion Enhances Vascular Dysplasia and Hemorrhage in the Brain of Adult Alk1 Heterozygous Mice. Transl Stroke Res 2016; 7:488-496. [PMID: 27352867 DOI: 10.1007/s12975-016-0478-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Revised: 06/13/2016] [Accepted: 06/16/2016] [Indexed: 10/21/2022]
Abstract
Brain arteriovenous malformation (bAVM), characterized by tangled dysplastic vessels, is an important cause of intracranial hemorrhage in young adults, and its pathogenesis and progression are not fully understood. Patients with haploinsufficiency of transforming growth factor-β (TGF-β) receptors, activin receptor-like kinase 1 (ALK1) or endoglin (ENG) have a higher incidence of bAVM than the general population. However, bAVM does not develop effectively in mice with the same haploinsufficiency. The expression of integrin β8 subunit (ITGB8), another member in the TGF-β superfamily, is reduced in sporadic human bAVM. Brain angiogenic stimulation results at the capillary level of vascular malformation in adult Alk1 haploinsufficient (Alk1 +/- ) mice. We hypothesized that deletion of Itgb8 enhances bAVM development in adult Alk1 +/- mice. An adenoviral vector expressing Cre recombinase (Ad-Cre) was co-injected with an adeno-associated viral vector expressing vascular endothelial growth factor (AAV-VEGF) into the brain of Alk1 +/-;Itgb8-floxed mice to induce focal Itgb8 gene deletion and angiogenesis. We showed that compared with Alk +/- mice (4.75 ± 1.38/mm2), the Alk1 +/-;Itgb8-deficient mice had more dysplastic vessels in the angiogenic foci (7.14 ± 0.68/mm2, P = 0.003). More severe hemorrhage was associated with dysplastic vessels in the brain of Itgb8-deleted Alk1 +/- , as evidenced by larger Prussian blue-positive areas (1278 ± 373 pixels/mm2 vs. Alk1 +/- : 320 ± 104 pixels/mm2; P = 0.028). These data indicate that both Itgb8 and Alk1 are important in maintaining normal cerebral angiogenesis in response to VEGF. Itgb8 deficiency enhances the formation of dysplastic vessels and hemorrhage in Alk1 +/- mice.
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Kim H, Pawlikowska L, Su H, Young WL. Genetics and Vascular Biology of Angiogenesis and Vascular Malformations. Stroke 2016. [DOI: 10.1016/b978-0-323-29544-4.00012-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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12
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Zhang R, Zhu W, Su H. Vascular Integrity in the Pathogenesis of Brain Arteriovenous Malformation. ACTA NEUROCHIRURGICA. SUPPLEMENT 2016; 121:29-35. [PMID: 26463919 DOI: 10.1007/978-3-319-18497-5_6] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Brain arteriovenous malformation (bAVM) is an important cause of intracranial hemorrhage (ICH), particularly in the young population. ICH is the first clinical symptom in about 50 % of bAVM patients. The vessels in bAVM are fragile and prone to rupture, causing bleeding into the brain. About 30 % of unruptured and non-hemorrhagic bAVMs demonstrate microscopic evidence of hemosiderin in the vascular wall. In bAVM mouse models, vascular mural cell coverage is reduced in the AVM lesion, accompanied by vascular leakage and microhemorrhage. In this review, we discuss possible signaling pathways involved in abnormal vascular development in bAVM.
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Affiliation(s)
- Rui Zhang
- Department of Anesthesia and Perioperative Care, Center for Cerebrovascular Research, University of California, San Francisco, 1001 Potrero Avenue, 1363, San Francisco, CA, 94110, USA
| | - Wan Zhu
- Department of Anesthesia and Perioperative Care, Center for Cerebrovascular Research, University of California, San Francisco, 1001 Potrero Avenue, 1363, San Francisco, CA, 94110, USA
| | - Hua Su
- Department of Anesthesia and Perioperative Care, Center for Cerebrovascular Research, University of California, San Francisco, 1001 Potrero Avenue, 1363, San Francisco, CA, 94110, USA.
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Animal Models in Studying Cerebral Arteriovenous Malformation. BIOMED RESEARCH INTERNATIONAL 2015; 2015:178407. [PMID: 26649296 PMCID: PMC4663287 DOI: 10.1155/2015/178407] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/06/2015] [Revised: 10/11/2015] [Accepted: 10/25/2015] [Indexed: 12/13/2022]
Abstract
Brain arteriovenous malformation (AVM) is an important cause of hemorrhagic stroke. The etiology is largely unknown and the therapeutics are controversial. A review of AVM-associated animal models may be helpful in order to understand the up-to-date knowledge and promote further research about the disease. We searched PubMed till December 31, 2014, with the term “arteriovenous malformation,” limiting results to animals and English language. Publications that described creations of AVM animal models or investigated AVM-related mechanisms and treatments using these models were reviewed. More than 100 articles fulfilling our inclusion criteria were identified, and from them eight different types of the original models were summarized. The backgrounds and procedures of these models, their applications, and research findings were demonstrated. Animal models are useful in studying the pathogenesis of AVM formation, growth, and rupture, as well as in developing and testing new treatments. Creations of preferable models are expected.
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Yang ST, Rodriguez-Hernandez A, Walker EJ, Young WL, Su H, Lawton MT. Adult mouse venous hypertension model: common carotid artery to external jugular vein anastomosis. J Vis Exp 2015:50472. [PMID: 25650793 DOI: 10.3791/50472] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
The understanding of the pathophysiology of brain arteriovenous malformations and arteriovenous fistulas has improved thanks to animal models. A rat model creating an artificial fistula between the common carotid artery (CCA) and the external jugular vein (EJV) has been widely described and proved technically feasible. This construct provokes a consistent cerebral venous hypertension (CVH), and therefore has helped studying the contribution of venous hypertension to formation, clinical symptoms, and prognosis of brain AVMs and dural AVFs. Equivalent mice models have been only scarcely described and have shown trouble with stenosis of the fistula. An established murine model would allow the study of not only pathophysiology but also potential genetic therapies for these cerebrovascular diseases. We present a model of arteriovenous fistula that produces a durable intracranial venous hypertension in the mouse. Microsurgical anastomosis of the murine CCA and EJV can be difficult due to diminutive anatomy and frequently result in a non-patent fistula. In this step-by-step protocol we address all the important challenges encountered during this procedure. Avoiding excessive retraction of the vein during the exposure, using 11-0 sutures instead of 10-0, and making a carefully planned end-to-side anastomosis are some of the critical steps. Although this method requires advanced microsurgical skills and a longer learning curve that the equivalent in the rat, it can be consistently developed. This novel model has been designed to integrate transgenic mouse techniques with a previously well-established experimental system that has proved useful to study brain AVMs and dural AVFs. By opening the possibility of using transgenic mice, a broader spectrum of valid models can be achieved and genetic treatments can also be tested. The experimental construct could also be further adapted to the study of other cerebrovascular diseases related with venous hypertension such as migraine, transient global amnesia, transient monocular blindness, etc.
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Affiliation(s)
- Shun-Tai Yang
- Department of Anesthesia and Perioperative Care and Center for Cerebrovascular Research, University of California, San Francisco
| | | | - Espen J Walker
- Department of Anesthesia and Perioperative Care and Center for Cerebrovascular Research, University of California, San Francisco
| | - William L Young
- Department of Anesthesia and Perioperative Care and Center for Cerebrovascular Research, University of California, San Francisco; Department of Neurological Surgery, University of California, San Francisco; Department of Neurology, University of California, San Francisco
| | - Hua Su
- Department of Anesthesia and Perioperative Care and Center for Cerebrovascular Research, University of California, San Francisco
| | - Michael T Lawton
- Department of Neurological Surgery, University of California, San Francisco;
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Roman BL, Finegold DN. Genetic and Molecular Basis for Hereditary Hemorrhagic Telangiectasia. CURRENT GENETIC MEDICINE REPORTS 2014. [DOI: 10.1007/s40142-014-0061-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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Ramey WL, Martirosyan NL, Zabramski JM, Spetzler RF, Kalani MYS. A hierarchical model for the development of cerebral arteriovenous malformations. Clin Neurol Neurosurg 2014; 126:126-9. [DOI: 10.1016/j.clineuro.2014.08.029] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2014] [Accepted: 08/24/2014] [Indexed: 11/26/2022]
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Brain arteriovenous malformation modeling, pathogenesis, and novel therapeutic targets. Transl Stroke Res 2014; 5:316-29. [PMID: 24723256 DOI: 10.1007/s12975-014-0343-0] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2014] [Revised: 03/24/2014] [Accepted: 03/25/2014] [Indexed: 02/07/2023]
Abstract
Patients harboring brain arteriovenous malformation (bAVM) are at life-threatening risk of rupture and intracranial hemorrhage (ICH). The pathogenesis of bAVM has not been completely understood. Current treatment options are invasive, and ≈ 20 % of patients are not offered interventional therapy because of excessive treatment risk. There are no specific medical therapies to treat bAVMs. The lack of validated animal models has been an obstacle for testing hypotheses of bAVM pathogenesis and testing new therapies. In this review, we summarize bAVM model development and bAVM pathogenesis and potential therapeutic targets that have been identified during model development.
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Walcott BP, Peterson RT. Zebrafish models of cerebrovascular disease. J Cereb Blood Flow Metab 2014; 34:571-7. [PMID: 24517974 PMCID: PMC3982096 DOI: 10.1038/jcbfm.2014.27] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/11/2013] [Revised: 12/27/2013] [Accepted: 01/07/2014] [Indexed: 12/18/2022]
Abstract
Perturbations in cerebral blood flow and abnormalities in blood vessel structure are the hallmarks of cerebrovascular disease. While there are many genetic and environmental factors that affect these entities through a heterogeneous group of disease processes, the ultimate final pathologic insult in humans is defined as a stroke, or damage to brain parenchyma. In the case of ischemic stroke, blood fails to reach its target destination whereas in hemorrhagic stroke, extravasation of blood occurs outside of the blood vessel lumen, resulting in direct damage to brain parenchyma. As these acute events can be neurologically devastating, if not fatal, development of novel therapeutics are urgently needed. The zebrafish (Danio rerio) is an attractive model for the study of cerebrovascular disease because of its morphological and physiological similarity to human cerebral vasculature, its ability to be genetically manipulated, and its fecundity allowing for large-scale, phenotype-based screens.
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Affiliation(s)
- Brian P Walcott
- Department of Neurosurgery, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, USA
- Cardiovascular Research Center, Massachusetts General Hospital and Harvard Medical School, Charlestown, Massachusetts, USA
| | - Randall T Peterson
- Cardiovascular Research Center, Massachusetts General Hospital and Harvard Medical School, Charlestown, Massachusetts, USA
- Broad Institute, Cambridge, Massachusetts, USA
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Navarrete MG, Hernández AD, Collado-Ortiz MA, Salinas-Lara C, Tena-Suck ML. Brain vascular lesions: a clinicopathologic, immunohistochemistry, and ultrastructural approach. Ann Diagn Pathol 2014; 18:193-8. [PMID: 24881784 DOI: 10.1016/j.anndiagpath.2014.01.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2013] [Accepted: 01/09/2014] [Indexed: 11/19/2022]
Abstract
Brain vascular malformations are relatively common lesions that cause serious neurologic disability or death in a significant proportion of individuals bearing them. The purpose of this study was to analyze the clinicopathologic and immunohistochemistry these lesions, looking for common antibodies expressed such as CD31, CD34, CD15, factor VIII, nestin, vimentin, vascular endothelial grow factor (VEGF), vascular endothelial grow factor receptor-2 (VEGF-R2), glial fibrillar acidic protien (GFAP), and fibroblastic grow factor β (β-FGF) and ultrastructure in endothelial cells as well as in vessel walls. Fifty cases of vascular lesions were included in this study: 29 (58%) of them were arteriovenous malformations and 21 (52%) were brain cavernomas. Twenty-six (52%) patients were women and 24 (48%) men. The age range was from 13 to 68 years (mean age, 35.86 ± 15.19 years). The size of the lesions ranged between 1 and 8 cm (3 ± 1.65 cm), and parieto-occipital lesions had a bigger size. Evolution time varied from 1 month to 1 year (mean, 7.5 months). There was a significant statistical correlation between age and sex (P = -035), rupture of lesion (P = .015), brain hemorrhage (P = .033), necrosis (P = .011), hemosiderin deposit (P = .042), VEGF (P = .015), and VEGFR (P = .037), as well as localization of rupture (P = .017), loss of consciousness (P = .000), visual deficit (P = .026), hyaline vessels (P = .000), and CD31 (.009). Interactions between endothelial cells and mural cells (pericytes and vascular smooth muscle cells) in blood vessel walls have recently come into focus as central processes in the regulation of vascular formation, stabilization, remodeling, and function in brain vascular lesions. However, the molecular mechanisms that underlie the formation and growth of brain arteriovenous malformations are still poorly understood.
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Affiliation(s)
- Marisol Galván Navarrete
- General Hospital of Guadalajara Hospital civil antiguo de Guadalajara Jalisco, Guadalajara, Mexico
| | - Alma Dalia Hernández
- Laboratory of Pathology, National Institute of Rehabilitation, México City, Mexico
| | - Miguel Angel Collado-Ortiz
- Neurological Center, Department of Clinical Neurophysiology, The American British Cowdray Hospital, Mexico City, Mexico.
| | - Citlaltepetl Salinas-Lara
- Department of Neuropathology, National Institute of Neurology and Neurosurgery, México City, Mexico.
| | - Martha Lilia Tena-Suck
- Department of Neuropathology, National Institute of Neurology and Neurosurgery, México City, Mexico.
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Abstract
Brain arteriovenous malformations (bAVM) are tangles of abnormal, dilated vessels that directly shunt blood between the arteries and veins. The pathogenesis of bAVM is currently unknown. Patients with hereditary hemorrhagic telangiectasia (HHT) have a higher prevalence of bAVM than the general population. Animal models are important tools for dissecting the disease etiopathogenesis and for testing new therapies. Here, we introduce a method that induces the bAVM phenotype through regional deletion of activin-like kinase 1 (Alk1, the causal gene for HHT2) and vascular endothelial growth factor (VEGF) stimulation.
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Affiliation(s)
- Wanqiu Chen
- Department of Anesthesia and Perioperative Care, Center for Cerebrovascular Research, University of California, San Francisco, San Francisco, CA, USA
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Atri D, Larrivée B, Eichmann A, Simons M. Endothelial signaling and the molecular basis of arteriovenous malformation. Cell Mol Life Sci 2013; 71:10.1007/s00018-013-1475-1. [PMID: 24077895 PMCID: PMC3969452 DOI: 10.1007/s00018-013-1475-1] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2013] [Revised: 09/08/2013] [Accepted: 09/10/2013] [Indexed: 12/21/2022]
Abstract
Arteriovenous malformations occur when abnormalities of vascular patterning result in the flow of blood from arteries to veins without an intervening capillary bed. Recent work has revealed the importance of the Notch and TGF-β signaling pathways in vascular patterning. Specifically, Notch signaling has an increasingly apparent role in arterial specification and suppression of branching, whereas TGF-β is implicated in vascular smooth muscle development and remodeling under angiogenic stimuli. These physiologic roles, consequently, have implicated both pathways in the pathogenesis of arteriovenous malformation. In this review, we summarize the studies of endothelial signaling that contribute to arteriovenous malformation and the roles of genes implicated in their pathogenesis. We further discuss how endothelial signaling may contribute to vascular smooth muscle development and how knowledge of signaling pathways may provide us targets for medical therapy in these vascular lesions.
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Affiliation(s)
- Deepak Atri
- Yale Cardiovascular Research Center, Section of Cardiovascular Medicine, Department of Internal Medicine, Yale University School of Medicine, New Haven, United States
| | - Bruno Larrivée
- Yale Cardiovascular Research Center, Section of Cardiovascular Medicine, Department of Internal Medicine, Yale University School of Medicine, New Haven, United States
- Department of Ophthalmology, Hôpital Maisonneuve-Rosemont Research Centre, University of Montreal, Montreal, Canada
| | - Anne Eichmann
- Yale Cardiovascular Research Center, Section of Cardiovascular Medicine, Department of Internal Medicine, Yale University School of Medicine, New Haven, United States
- Center for Interdisciplinary Research in Biology (CIRB), Collège de France, Paris, France
| | - Michael Simons
- Yale Cardiovascular Research Center, Section of Cardiovascular Medicine, Department of Internal Medicine, Yale University School of Medicine, New Haven, United States
- Department of Cell Biology, Yale University School of Medicine, New Haven, United States
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The ALK-1/Smad1 pathway in cardiovascular physiopathology. A new target for therapy? Biochim Biophys Acta Mol Basis Dis 2013; 1832:1492-510. [PMID: 23707512 DOI: 10.1016/j.bbadis.2013.05.016] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2013] [Revised: 05/04/2013] [Accepted: 05/13/2013] [Indexed: 01/04/2023]
Abstract
Activin receptor-like kinase-1 or ALK-1 is a type I cell surface receptor for the transforming growth factor-β (TGF-β) family of proteins. The role of ALK-1 in endothelial cells biology and in angiogenesis has been thoroughly studied by many authors. However, it has been recently suggested a possible role of ALK-1 in cardiovascular homeostasis. ALK-1 is not only expressed in endothelial cells but also in smooth muscle cells, myofibroblast, hepatic stellate cells, chondrocytes, monocytes, myoblasts, macrophages or fibroblasts, but its role in these cells have not been deeply analyzed. Due to the function of ALK-1 in these cells, this receptor plays a role in several cardiovascular diseases. Animals with ALK-1 haploinsufficiency and patients with mutations in Acvrl1 (the gene that codifies for ALK-1) develop type-2 Hereditary Hemorrhagic Telangiectasia. Moreover, ALK-1 heterozygous mice develop pulmonary hypertension. Higher levels of ALK-1 have been observed in atherosclerotic plaques, suggesting a possible protector role of this receptor. ALK-1 deficiency is also related to the development of arteriovenous malformations (AVMs). Besides, due to the ability of ALK-1 to regulate cell proliferation and migration, and to modulate extracellular matrix (ECM) protein expression in several cell types, ALK-1 has been now demonstrated to play an important role in cardiovascular remodeling. In this review, we would like to offer a complete vision of the role of ALK-1 in many process related to cardiovascular homeostasis, and the involvement of this protein in the development of cardiovascular diseases, suggesting the possibility of using the ALK-1/smad-1 pathway as a powerful therapeutic target.
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23
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Seghers L, de Vries MR, Pardali E, Hoefer IE, Hierck BP, ten Dijke P, Goumans MJ, Quax PHA. Shear induced collateral artery growth modulated by endoglin but not by ALK1. J Cell Mol Med 2013; 16:2440-50. [PMID: 22436015 PMCID: PMC3823438 DOI: 10.1111/j.1582-4934.2012.01561.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Transforming growth factor-beta (TGF-β) stimulates both ischaemia induced angiogenesis and shear stress induced arteriogenesis by signalling through different receptors. How these receptors are involved in both these processes of blood flow recovery is not entirely clear. In this study the role of TGF-β receptors 1 and endoglin is assessed in neovascularization in mice. Unilateral femoral artery ligation was performed in mice heterozygous for either endoglin or ALK1 and in littermate controls. Compared with littermate controls, blood flow recovery, monitored by laser Doppler perfusion imaging, was significantly hampered by maximal 40% in endoglin heterozygous mice and by maximal 49% in ALK1 heterozygous mice. Collateral artery size was significantly reduced in endoglin heterozygous mice compared with controls but not in ALK1 heterozygous mice. Capillary density in ischaemic calf muscles was unaffected, but capillaries from endoglin and ALK1 heterozygous mice were significantly larger when compared with controls. To provide mechanistic evidence for the differential role of endoglin and ALK1 in shear induced or ischaemia induced neovascularization, murine endothelial cells were exposed to shear stress in vitro. This induced increased levels of endoglin mRNA but not ALK1. In this study it is demonstrated that both endoglin and ALK1 facilitate blood flow recovery. Importantly, endoglin contributes to both shear induced collateral artery growth and to ischaemia induced angiogenesis, whereas ALK1 is only involved in ischaemia induced angiogenesis.
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Affiliation(s)
- Leonard Seghers
- Department of Surgery, Leiden University Medical Center, Leiden, The Netherlands
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Choi EJ, Walker EJ, Shen F, Oh SP, Arthur HM, Young WL, Su H. Minimal homozygous endothelial deletion of Eng with VEGF stimulation is sufficient to cause cerebrovascular dysplasia in the adult mouse. Cerebrovasc Dis 2012; 33:540-7. [PMID: 22571958 PMCID: PMC3569027 DOI: 10.1159/000337762] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2011] [Accepted: 03/05/2012] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Brain arteriovenous malformations (bAVMs) represent a high risk for hemorrhagic stroke, leading to significant neurological morbidity and mortality in young adults. The etiopathogenesis of bAVM remains unclear. Research progress has been hampered by the lack of animal models. Hereditary Hemorrhagic Telangiectasia (HHT) patients with haploinsufficiency of endoglin (ENG, HHT1) or activin receptor-like kinase 1 (ALK1, HHT2) have a higher incidence of bAVM than the general population. We previously induced cerebrovascular dysplasia in the adult mouse that resembles human bAVM through Alk1 deletion plus vascular endothelial growth factor (VEGF) stimulation. We hypothesized that Eng deletion plus VEGF stimulation would induce a similar degree of cerebrovascular dysplasia as the Alk1-deleted brain. METHODS Ad-Cre (an adenoviral vector expressing Cre recombinase) and AAV-VEGF (an adeno-associated viral vector expressing VEGF) were co-injected into the basal ganglia of 8- to 10-week-old Eng(2f/2f) (exons 5 and 6 flanked by loxP sequences), Alk1(2f/2f) (exons 4-6 flanked by loxP sequences) and wild-type (WT) mice. Vascular density, dysplasia index, and gene deletion efficiency were analyzed 8 weeks later. RESULTS AAV-VEGF induced a similar degree of angiogenesis in the brain with or without Alk1- or Eng-deletion. Abnormally patterned and dilated dysplastic vessels were found in the viral vector-injected region of Alk1(2f/2f) and Eng(2f/2f) brain sections, but not in WT. Alk1(2f/2f) mice had about 1.8-fold higher dysplasia index than Eng(2f/2f) mice (4.6 ± 1.9 vs. 2.5 ± 1.1, p < 0.05). However, after normalization of the dysplasia index with the gene deletion efficiency (Alk1(2f/2f): 16% and Eng(2f/2f): 1%), we found that about 8-fold higher dysplasia was induced per copy of Eng deletion (2.5) than that of Alk1 deletion (0.3). ENG-negative endothelial cells were detected in the Ad-Cre-treated brain of Eng(2f/2f) mice, suggesting homozygous deletion of Eng in the cells. VEGF induced more severe vascular dysplasia in the Ad-Cre-treated brain of Eng(2f/2f) mice than that of Eng(+/-) mice. CONCLUSIONS (1) Deletion of Eng induces more severe cerebrovascular dysplasia per copy than that of Alk1 upon VEGF stimulation. (2) Homozygous deletion of Eng with angiogenic stimulation may be a promising strategy for development of a bAVM mouse model. (3) The endothelial cells that have homozygous causal gene deletion in AVM could be crucial for lesion development.
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Affiliation(s)
- Eun-Jung Choi
- Center for Cerebrovascular Research, Department of Anesthesia and Perioperative Care, University of California, San Francisco, San Francisco, CA, USA
| | - Espen J. Walker
- Center for Cerebrovascular Research, Department of Anesthesia and Perioperative Care, University of California, San Francisco, San Francisco, CA, USA
| | - Fanxia Shen
- Center for Cerebrovascular Research, Department of Anesthesia and Perioperative Care, University of California, San Francisco, San Francisco, CA, USA
| | - S. Paul Oh
- Shands Cancer Center, Department of Physiology and Functional Genomics, University of Florida, Gainesville, FL, USA
| | - Helen M. Arthur
- Institute of Human Genetics, International Centre for Life, Newcastle University, Newcastle, United Kingdom
| | - William L. Young
- Center for Cerebrovascular Research, Department of Anesthesia and Perioperative Care, University of California, San Francisco, San Francisco, CA, USA
- Department of Neurological Surgery, University of California, San Francisco, San Francisco, CA, USA
- Department of Neurology, University of California, San Francisco, San Francisco, CA, USA
| | - Hua Su
- Center for Cerebrovascular Research, Department of Anesthesia and Perioperative Care, University of California, San Francisco, San Francisco, CA, USA
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Walker EJ, Su H, Shen F, Degos V, Amend G, Jun K, Young WL. Bevacizumab attenuates VEGF-induced angiogenesis and vascular malformations in the adult mouse brain. Stroke 2012; 43:1925-30. [PMID: 22569934 DOI: 10.1161/strokeaha.111.647982] [Citation(s) in RCA: 91] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
BACKGROUND AND PURPOSE Vascular endothelial growth factor (VEGF) expression is elevated in human brain arteriovenous malformations (bAVM). We have developed a bAVM model in the adult mouse by focal Alk1 gene deletion and human VEGF stimulation. We hypothesized that once the abnormal vasculature has been established, tonic VEGF stimulation is necessary to maintain the abnormal phenotype, and VEGF antagonism by bevacizumab (Avastin) would reduce vessel density and attenuate the dysplastic vascular phenotype. METHODS Angiogenesis and bAVM were induced by injection of adeno-associated viral vector expressing human VEGF alone into the brain of wild-type mice or with adenoviral vector expressing Cre recombinase (Ad-Cre) into Alk1(2f/2f) mice. Six weeks later, bevacizumab or trastuzumab (Herceptin, bevacizumab control) was administered. Vessel density, dysplasia index, vascular cell proliferation and apoptosis, and human IgG were assessed (n=6/group). RESULTS Compared with trastuzumab (15 mg/kg), administration of 5, 10, and 15 mg/kg of bevacizumab to adeno-associated viral vector expressing human VEGF treated wild-type mice reduced focal vessel density (P<0.05); administration of 5 mg/kg bevacizumab decreased proliferating vascular cells (P=0.04) and increased TUNEL-positive vascular cells (P=0.03). More importantly, bevacizumab (5 mg/kg) treatment reduced both vessel density (P=0.01) and dysplasia index (P=0.02) in our bAVM model. Human IgG was detected in the vessel wall and in the parenchyma in the angiogenic foci of bevacizumab-treated mice. CONCLUSIONS We provide proof-of-principle that, once abnormal AVM vessels have formed, VEGF antagonism may reduce the number of dysplastic vessels and should be evaluated further as a therapeutic strategy for the human disease.
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Affiliation(s)
- Espen J Walker
- Center for Cerebrovascular Research, University of California, San Francisco, Department of Anesthesia and Perioperative Care, 1001 Potrero Avenue, Room 3C-38, San Francisco, CA 94110, USA
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Kuroshima S, Go VAA, Yamashita J. Increased numbers of nonattached osteoclasts after long-term zoledronic acid therapy in mice. Endocrinology 2012; 153:17-28. [PMID: 22109892 PMCID: PMC3249684 DOI: 10.1210/en.2011-1439] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2011] [Accepted: 10/28/2011] [Indexed: 01/09/2023]
Abstract
Osteoclasts are key players in the maintenance of bone, which is an endocrine target and organ. Bisphosphonates, used for the management of metastatic bone diseases and osteoporosis, suppress osteoclasts. However, the impact of continuously suppressed osteoclasts is unknown. In this study, mice received zoledronic acid (ZA) for 13 months, nearly half the lifespan of mice, and the effects of continual osteoclast suppression on the bone environment and oral wound healing were determined. ZA therapy suppressed osteoclasts, resulting in significantly more bone mass compared with control. Despite continuous and intense suppression of bone loss in mice receiving ZA, serum calcium levels were maintained in the normal range. No differences were noted in serum tartrate-resistant acid phosphatase (TRAP) 5b levels between ZA-treated and control mice. Histomorphometric analyses of bones revealed that ZA therapy significantly decreased osteoclasts on the bone surface but, instead, substantially increased TRAP(+) mononuclear cells and osteoclasts that were not on the bone surface. When oral trauma was induced, such TRAP(+) mononuclear and nonattached osteoclasts increased considerably with increased inflammatory cell infiltration in the wounds. As a result, oral wound healing was hindered at the connective tissue level. Healing of the epithelium was unaffected. These findings indicate that the continual suppression of osteoclasts does not affect serum calcium levels and that long-term ZA therapy stimulates nonattached osteoclast and TRAP(+) mononuclear cell formation that are expanded rapidly in response to oral trauma. Caution should be exercised when using the serum TRAcP5b to estimate the efficacy of antiresorptive therapy.
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Affiliation(s)
- Shinichiro Kuroshima
- Department of Biologic and Materials Sciences, University of Michigan School of Dentistry, 1011 North University Avenue, Ann Arbor, Michigan 48109-1078, USA
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Walker EJ, Su H, Shen F, Choi EJ, Oh SP, Chen G, Lawton MT, Kim H, Chen Y, Chen W, Young WL. Arteriovenous malformation in the adult mouse brain resembling the human disease. Ann Neurol 2011; 69:954-62. [PMID: 21437931 DOI: 10.1002/ana.22348] [Citation(s) in RCA: 104] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2010] [Revised: 11/12/2010] [Accepted: 12/03/2010] [Indexed: 12/17/2022]
Abstract
OBJECTIVE Brain arteriovenous malformations (bAVMs) are an important cause of hemorrhagic stroke. The underlying mechanisms are not clear. No animal model for adult bAVM is available for mechanistic exploration. Patients with hereditary hemorrhagic telangiectasia type 2 (HHT2) with activin receptor-like kinase 1 (ALK1; ACVRL1) mutations have a higher incidence of bAVM than the general population. We tested the hypothesis that vascular endothelial growth factor (VEGF) stimulation with regional homozygous deletion of Alk1 induces severe dysplasia in the adult mouse brain, akin to human bAVM. METHODS Alk1(2f/2f) (exons 4-6 flanked by loxP sites) and wild-type (WT) mice (8-10 weeks old) were injected with adenoviral vector expressing Cre recombinase (Ad-Cre; 2 × 10(7) plaque forming units [PFU]) and adeno-associated viral vectors expressing VEGF (AAV-VEGF; 2 × 10(9) genome copies) into the basal ganglia. At 8 weeks, blood vessels were analyzed. RESULTS Gross vascular irregularities were seen in Alk1(2f/2f) mouse brain injected with Ad-Cre and AAV-VEGF. The vessels were markedly enlarged with abnormal patterning resembling aspects of the human bAVM phenotype, displayed altered expression of the arterial and venous markers (EphB4 and Jagged-1), and showed evidence of arteriovenous shunting. Vascular irregularities were not seen in similarly treated WT mice. INTERPRETATION Our data indicate that postnatal, adult formation of the human disease, bAVM, is possible, and that both genetic mutation and angiogenic stimulation are necessary for lesion development. Our work not only provides a testable adult mouse bAVM model for the first time, but also suggests that specific medical therapy can be developed to slow bAVM growth and potentially stabilize the rupture-prone abnormal vasculature.
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Affiliation(s)
- Espen J Walker
- Center for Cerebrovascular Research, Department of Anesthesia and Perioperative Care, University of California, San Francisco, San Francisco, CA 94110, USA
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Corti P, Young S, Chen CY, Patrick MJ, Rochon ER, Pekkan K, Roman BL. Interaction between alk1 and blood flow in the development of arteriovenous malformations. Development 2011; 138:1573-82. [PMID: 21389051 DOI: 10.1242/dev.060467] [Citation(s) in RCA: 160] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Arteriovenous malformations (AVMs) are fragile direct connections between arteries and veins that arise during times of active angiogenesis. To understand the etiology of AVMs and the role of blood flow in their development, we analyzed AVM development in zebrafish embryos harboring a mutation in activin receptor-like kinase I (alk1), which encodes a TGFβ family type I receptor implicated in the human vascular disorder hereditary hemorrhagic telangiectasia type 2 (HHT2). Our analyses demonstrate that increases in arterial caliber, which stem in part from increased cell number and in part from decreased cell density, precede AVM development, and that AVMs represent enlargement and stabilization of normally transient arteriovenous connections. Whereas initial increases in endothelial cell number are independent of blood flow, later increases, as well as AVMs, are dependent on flow. Furthermore, we demonstrate that alk1 expression requires blood flow, and despite normal levels of shear stress, some flow-responsive genes are dysregulated in alk1 mutant arterial endothelial cells. Taken together, our results suggest that Alk1 plays a role in transducing hemodynamic forces into a biochemical signal required to limit nascent vessel caliber, and support a novel two-step model for HHT-associated AVM development in which pathological arterial enlargement and consequent altered blood flow precipitate a flow-dependent adaptive response involving retention of normally transient arteriovenous connections, thereby generating AVMs.
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Affiliation(s)
- Paola Corti
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, USA
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30
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Kim H, Su H, Weinsheimer S, Pawlikowska L, Young WL. Brain arteriovenous malformation pathogenesis: a response-to-injury paradigm. ACTA NEUROCHIRURGICA. SUPPLEMENT 2011; 111:83-92. [PMID: 21725736 PMCID: PMC3187860 DOI: 10.1007/978-3-7091-0693-8_14] [Citation(s) in RCA: 97] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Brain arteriovenous malformations (AVMs) are a rare but important cause of intracranial hemorrhage (ICH) in young adults. In this paper, we review both human and animal studies of brain AVM, focusing on the: (1) natural history of AVM hemorrhage, (2) genetic and expression studies of AVM susceptibility and hemorrhage, and (3) strategies for development of a brain AVM model in adult mice. These data target various mechanisms that must act in concert to regulate normal angiogenic response to injury. Based on the various lines of evidence reviewed in this paper, we propose a "response-to-injury" model of brain AVM pathogenesis.
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Affiliation(s)
- Helen Kim
- Center for Cerebrovascular Research, Department of Anesthesia and Perioperative Care, University of California, San Francisco, CA, USA
- Department of Epidemiology and Biostatistics, University of California, San Francisco, CA, USA
- Institute for Human Genetics, University of California, San Francisco, CA, USA
| | - Hua Su
- Center for Cerebrovascular Research, Department of Anesthesia and Perioperative Care, University of California, San Francisco, CA, USA
| | - Shantel Weinsheimer
- Center for Cerebrovascular Research, Department of Anesthesia and Perioperative Care, University of California, San Francisco, CA, USA
| | - Ludmila Pawlikowska
- Center for Cerebrovascular Research, Department of Anesthesia and Perioperative Care, University of California, San Francisco, CA, USA
- Institute for Human Genetics, University of California, San Francisco, CA, USA
| | - William L. Young
- Center for Cerebrovascular Research, Department of Anesthesia and Perioperative Care, University of California, San Francisco, CA, USA
- Department of Neurological Surgery, University of California, San Francisco, CA, USA
- Department of Neurology, University of California, San Francisco, CA, USA
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31
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Jerkic M, Peter M, Ardelean D, Fine M, Konerding MA, Letarte M. Dextran sulfate sodium leads to chronic colitis and pathological angiogenesis in Endoglin heterozygous mice. Inflamm Bowel Dis 2010; 16:1859-70. [PMID: 20848471 PMCID: PMC2959118 DOI: 10.1002/ibd.21288] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
BACKGROUND Pathological angiogenesis is an intrinsic component of chronic intestinal inflammation, which results in remodeling and expansion of the gut microvascular bed. Endoglin is essential for endothelial cell function and physiological angiogenesis. In this study we investigated its potential role in the regulation of inflammation by testing the response of Endoglin heterozygous (Eng(+/-)) mice to experimental colitis. METHODS C57BL/6 Eng(+/-) and littermate control mice drank water supplemented with 3% dextran sulfate sodium (DSS) for 5 days and were monitored for up to 26 days for clinical signs of colitis. Inflammation, crypt damage, and angiogenic index were scored on histological sections of distal colon. Levels of the vascular endothelial growth factor (VEGF) and angiopoietins were measured by real-time polymerase chain reaction, enzyme-linked immunosorbent assay, and/or Western blots. Vascular permeability was assessed using Evans Blue. RESULTS Eng(+/-) and control mice developed acute colitis, which peaked at day 9. While control mice recovered by days 19-26, Eng(+/-) mice progressed to chronic colitis and showed numerous vascular protrusions penetrating into the serosa of the inflamed distal colon. Prior to DSS induction, VEGF levels and vascular permeability were higher in the distal colon of Eng(+/-) mice, while angiopoietin 1 and 2 levels were unchanged. In the chronic phase of colitis, VEGF levels were increased in both groups of mice and remained significantly higher in the Eng(+/-) mice. CONCLUSIONS Higher VEGF levels and increased vascular permeability in the distal colon may predispose Eng(+/-) mice to progress to chronic and persistent bowel inflammation, associated with pathological angiogenesis.
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Affiliation(s)
- Mirjana Jerkic
- Molecular Structure and Function Program, Hospital for Sick Children,The Heart and Stroke Foundation Richard Lewar Centre of Excellence, University of Toronto
| | - Madonna Peter
- Molecular Structure and Function Program, Hospital for Sick Children,Department of Immunology, University of Toronto
| | - Daniela Ardelean
- Molecular Structure and Function Program, Hospital for Sick Children,Division of Pediatric Rheumatology, Hospital for Sick Children
| | | | | | - Michelle Letarte
- Molecular Structure and Function Program, Hospital for Sick Children,The Heart and Stroke Foundation Richard Lewar Centre of Excellence, University of Toronto,Department of Immunology, University of Toronto
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Hao Q, Zhu Y, Su H, Shen F, Yang GY, Kim H, Young WL. VEGF Induces More Severe Cerebrovascular Dysplasia in Endoglin than in Alk1 Mice. Transl Stroke Res 2010; 1:197-201. [PMID: 20640035 PMCID: PMC2902730 DOI: 10.1007/s12975-010-0020-x] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Brain arteriovenous malformations (BAVMs) are an important cause of intracranial hemorrhage (ICH) in young adults. A small percent of BAVMs is due to hereditary hemorrhagic telangiectasia 1 and 2 (HHT1 and 2), which are caused by mutations in two genes involved in TGF-β signaling: endoglin (ENG) and activin-like kinase 1 (ALK1). The BAVM phenotype is an incomplete penetrant in HHT patients, and the mechanism is unknown. We tested the hypothesis that a "response-to-injury" triggers abnormal vascular (dysplasia) development, using Eng and Alk1 haploinsufficient mice. Adeno-associated virus (AAV) expressing vascular endothelial growth factor (VEGF) was used to mimic the injury conditions. VEGF overexpression caused a similar degree of angiogenesis in the brain of all groups, except that the cortex of Alk1(+/-) mice had a 33% higher capillary density than other groups. There were different levels of cerebrovascular dysplasia in haploinsufficient mice (Eng(+/)>Alk1(+/-)), which simulates the relative penetrance of BAVM in HHT patients (HHT1>HHT2). Few dysplastic capillaries were observed in AAV-LacZ-injected mice. Our data indicate that both angiogenic stimulation and genetic alteration are necessary for the development of dysplasia, suggesting that anti-angiogenic therapies might be adapted to slow the progression of the disease and decrease the risk of spontaneous ICH.
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Affiliation(s)
- Qi Hao
- Center for Cerebrovascular Research, Department of Anesthesia and Perioperative Care, University of California, San Francisco, 1001 Potrero Avenue Room 3C-38, San Francisco, CA 94110, USA
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33
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Leblanc GG, Golanov E, Awad IA, Young WL. Biology of vascular malformations of the brain. Stroke 2009; 40:e694-702. [PMID: 19834013 DOI: 10.1161/strokeaha.109.563692] [Citation(s) in RCA: 152] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
BACKGROUND AND PURPOSE This review discusses recent research on the genetic, molecular, cellular, and developmental mechanisms underlying the etiology of vascular malformations of the brain (VMBs), including cerebral cavernous malformation, sporadic brain arteriovenous malformation, and the arteriovenous malformations of hereditary hemorrhagic telangiectasia. Summary of Review- The identification of gene mutations and genetic risk factors associated with cerebral cavernous malformation, hereditary hemorrhagic telangiectasia, and sporadic arteriovenous malformation has enabled the development of animal models for these diseases and provided new insights into their etiology. All of the genes associated with VMBs to date have known or plausible roles in angiogenesis and vascular remodeling. Recent work suggests that the angiogenic process most severely disrupted by VMB gene mutation is that of vascular stabilization, the process whereby vascular endothelial cells form capillary tubes, strengthen their intercellular junctions, and recruit smooth muscle cells to the vessel wall. In addition, there is now good evidence that in some cases, cerebral cavernous malformation lesion formation involves a genetic 2-hit mechanism in which a germline mutation in one copy of a cerebral cavernous malformation gene is followed by a somatic mutation in the other copy. There is also increasing evidence that environmental second hits can produce lesions when there is a mutation to a single allele of a VMB gene. CONCLUSIONS Recent findings begin to explain how mutations in VMB genes render vessels vulnerable to rupture when challenged with other inauspicious genetic or environmental factors and have suggested candidate therapeutics. Understanding of the cellular mechanisms of VMB formation and progression in humans has lagged behind that in animal models. New knowledge of lesion biology will spur new translational work. Several well-established clinical and genetic database efforts are already in place, and further progress will be facilitated by collaborative expansion and standardization of these.
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Affiliation(s)
- Gabrielle G Leblanc
- National Institute of Neurological Disorders and Stroke, Bethesda, Md., USA.
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Chen Y, Hao Q, Kim H, Su H, Letarte M, Karumanchi SA, Lawton MT, Barbaro NM, Yang GY, Young WL. Soluble endoglin modulates aberrant cerebral vascular remodeling. Ann Neurol 2009; 66:19-27. [PMID: 19670444 DOI: 10.1002/ana.21710] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
OBJECTIVE Brain arteriovenous malformations (AVMs) are an important cause of neurological morbidity in young adults. The pathophysiology of these lesions is poorly understood. A soluble form of endoglin (sEng) has been shown to cause endothelial dysfunction and induce preeclampsia. We tested if sEng would be elevated in brain AVM tissues relative to epilepsy brain tissues, and also investigated whether sEng overexpression via gene transfer in the mouse brain would induce vascular dysplasia and associated changes in downstream signaling pathways. METHODS Expression levels of sEng in surgical specimens were determined by Western blot assay and enzyme-linked immunosorbent assay. Vascular dysplasia, levels of matrix metalloproteinase (MMP), and oxidative stress were determined by immunohistochemistry and gelatin zymography. RESULTS Brain AVMs (n = 33) had higher mean sEng levels (245 +/- 175 vs 100 +/- 60, % of control, p = 0.04) compared with controls (n = 8), as determined by Western blot. In contrast, membrane-bound Eng was not significantly different (108 +/- 79 vs 100 +/- 63, % of control, p = 0.95). sEng gene transduction in the mouse brain induced abnormal vascular structures. It also increased MMP activity by 490 +/- 30% (MMP-9) and 220 +/- 30% (MMP-2), and oxidants by 260 +/- 20% (4-hydroxy-2-nonenal) at 2 weeks after injection, suggesting that MMPs and oxidative radicals may mediate sEng-induced pathological vascular remodeling. INTERPRETATION The results suggest that elevated sEng may play a role in the generation of sporadic brain AVMs. Our findings may provide new targets for therapeutic intervention for patients with brain AVMs. Ann Neurol 2009;66:19-27.
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Affiliation(s)
- Yongmei Chen
- Department of Anesthesia and Perioperative Care, Center for Cerebrovascular Research, University of California San Francisco, San Francisco, CA, USA
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Murphy PA, Lu G, Shiah S, Bollen AW, Wang RA. Endothelial Notch signaling is upregulated in human brain arteriovenous malformations and a mouse model of the disease. J Transl Med 2009; 89:971-82. [PMID: 19546852 PMCID: PMC3095492 DOI: 10.1038/labinvest.2009.62] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Brain arteriovenous malformations (BAVMs) can cause lethal hemorrhagic stroke and have no effective treatment. The cellular and molecular basis for this disease is largely unknown. We have previously shown that expression of constitutively-active Notch4 receptor in the endothelium elicits and maintains the hallmarks of BAVM in mice, thus establishing a mouse model of the disease. Our work suggested that Notch pathway could be a critical molecular mediator of BAVM pathogenesis. Here, we investigated the hypothesis that upregulated Notch activation contributes to the pathogenesis of human BAVM. We examined the expression of the canonical Notch downstream target Hes1 in the endothelium of human BAVMs by immunofluorescence, and showed increased levels relative to either autopsy or surgical biopsy controls. We then analyzed receptor activity using an antibody to the activated form of the Notch1 receptor, and found increased levels of activity. These findings suggest that Notch activation may promote the development and even maintenance of BAVM. We also detected increases in Hes1 and activated Notch1 expression in our mouse model of BAVM induced by constitutively active Notch4, demonstrating molecular similarity between the mouse model and the human disease. Our work suggests that activation of Notch signaling is an important molecular candidate in BAVM pathogenesis and further validates that our animal model provides a platform to study the progression as well as the regression of the disease.
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Affiliation(s)
- Patrick A. Murphy
- Pacific Vascular Research Laboratory, Division of Vascular Surgery, Department of Surgery, and Department of Anatomy, University of California, San Francisco, CA 94143
| | - Gloria Lu
- Pacific Vascular Research Laboratory, Division of Vascular Surgery, Department of Surgery, and Department of Anatomy, University of California, San Francisco, CA 94143
| | - Steven Shiah
- Pacific Vascular Research Laboratory, Division of Vascular Surgery, Department of Surgery, and Department of Anatomy, University of California, San Francisco, CA 94143
| | - Andrew W. Bollen
- Department of Pathology, University of California, San Francisco, CA 94143
| | - Rong A. Wang
- Pacific Vascular Research Laboratory, Division of Vascular Surgery, Department of Surgery, and Department of Anatomy, University of California, San Francisco, CA 94143,Corresponding author: Rong A. Wang, Ph.D., University of California, HSW 1618, Box 0507, 513 Parnassus Ave., San Francisco, CA 94143-0507, , Ph: 415-476-6855, Fax: 415-564-5698
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