Brain AVM Models and Novel Therapeutic Targets I have nothing to - - PowerPoint PPT Presentation

▶
brain avm models and novel therapeutic targets
SMART_READER_LITE
LIVE PREVIEW

Brain AVM Models and Novel Therapeutic Targets I have nothing to - - PowerPoint PPT Presentation

Oct 12, 2023 37 likes •120 views

9/6/2014 Brain AVM Models and Novel Therapeutic Targets I have nothing to disclose. 2 nd UCSF Stroke and Aneurysm Update CME Saturday September 6, 2014 Hua Su, MD. Professor Center for Cerebrovascular Research Department of Anesthesia and

slide-1
SLIDE 1

9/6/2014 1

CCR UCSF center for cerebrovascular research

Brain AVM Models and Novel Therapeutic Targets

2nd UCSF Stroke and Aneurysm Update CME Saturday September 6, 2014

Hua Su, MD. Professor Center for Cerebrovascular Research Department of Anesthesia and Perioperative Care University of California, San Francisco Hua.su@ucsf.edu

CCR UCSF center for cerebrovascular research

I have nothing to disclose.

CCR UCSF center for cerebrovascular research

Brain Arteriovenous Malformations (AVMs)

  • Tangle of abnormal blood vessels (nidus)

–Arteriovenous shunting –No intranidal capillary bed –Range of vessel types

  • Located randomly throughout brain
  • Cause of hemorrhagic stroke

CCR UCSF center for cerebrovascular research

Current Treatments

Surgery, embolization and radiosurgery No specific medical therapy for brain AVM

Death or Stoke (%) Months Invasive therapy (n=114) HR=0.27 (95% CI: 0.14-0.54)

Medical management (n=109)

The goals of specific medical treatments are:

  • 1. Stabilize vessel wall
  • reduce spontaneous intracranial hemorrhage and hemorrhagic

stroke

  • 2. Reduce brain AVM grow or regrow after invasive treatment
  • 3. Reduce AVM volume
  • surgical resection easier
  • reduce risk of invasive procedures
slide-2
SLIDE 2

9/6/2014 2

CCR UCSF center for cerebrovascular research

Identify Specific Targets

  • Analyzing surgical specimens
  • Modeling brain AVM in animals

CCR UCSF center for cerebrovascular research

Macrophage & Leukocytes

smooth muscle

VEGF VEGF-R MMP-9 Tie-2 Imbalance in Angiopoietin 1 & 2

astrocyte

Hashimoto, Neurosurgery 54: 410, 2004 Shenkar, Neurosurgery 52: 465, 2003 Kilic, Neurosurgery 57: 997, 2005 Sure, Neurosurgery 55: 663, 2004 Sonstein; J Neurosurg 85:838, 1996 ZhuGe, Q. et al. Brain 2009 Murphy, PA. Laboratory Investigation 2009 Tissue assays of surgical specimens: “angiogenesis run amok” “a healing wound”

endothelium

aVB3 Ki-67

HIF-1α Notch Notch

CCR UCSF center for cerebrovascular research

Are brain AVMs heritable?

  • Familial

– Hereditary Hemorrhagic Telangiectasias (HHT) – RASA1 (p120 RasGAP, is a Ras GTPase–activating protein) capillary malformation-AVM

  • Eerola, Am J Hum Genet 73: 1240, 2003

– Non-HHT

  • 53 patients in 25 families

– van Beijnum, et al, JNNP 78: 1213, 2007 – Inoue, et al, Stroke 38: 1368, 2007

  • Sporadic

95-98% no family history

CCR UCSF center for cerebrovascular research

  • Autosomal dominant disorder
  • Mucocutaneous telangiectasia
  • AVMs in Liver, Lung and Brain
  • 80% of cases have functional heploinsufficiency of

Endoglin (HHT1) or ALK1 (HHT2)

Hereditary Hemorrhagic Telangiectasia (HHT) Rendu-Osler-Weber Syndrome

Liver AVM Lung AVM Brain AVMs

slide-3
SLIDE 3

9/6/2014 3

CCR UCSF center for cerebrovascular research

Eng+/- and Alk1+/- mice –minimal brain phenotype

Satomi, et al, Stroke 2003;34:783 Corrosion casting and SEM revealed AVMs in 3/10 mice Srinivasan, et al, Hum Mol Genet 12: 473, 2003 In >47 mice, one Alk1+/- with dilated cerebellar vessel

CCR UCSF center for cerebrovascular research

AdCre – Regional Conditional Deletion of Alk1

loxp loxp

CMV Promoter Cre recombinase Promoter Promoter

loxp

AdCre Exons 4, 5, 6 Exon 3 Exon 7 Exon 3 Alk 1 gene Exons 4,5,6 are deleted from Alk1 genome Exon 7

CCR UCSF center for cerebrovascular research

Alk1 Regional Conditional Deletion Plus VEGF Stimulation Results in Brain AVM

AdCre + AAV-VEGF

8 wks

Alk1-/- Angiogenesis

Walker et al. Ann Neurology, 2011 CCR UCSF center for cerebrovascular research

Alk1+/+/VEGF Alk1-/- only Alk1-/- /VEGF

VEGF Stimulation is Necessary for Brain AVM Formation

Alk1+/+/VEGF

Walker et al. Ann Neurology, 2011

slide-4
SLIDE 4

9/6/2014 4

CCR UCSF center for cerebrovascular research

Chen et al. Translational Stroke Research, 2014

Adult onset AVM models

Choi et al., PLOS One, 2014

CCR UCSF center for cerebrovascular research

Chen et al, Stroke, 2014

Some Models have AVM in Other Organs skin

CCR UCSF center for cerebrovascular research

Macrophage Infiltration

Chen et al. ATVB, 2013

CCR UCSF center for cerebrovascular research

AVM vessels have less smooth muscle cell coverage

Chen et al. ATVB, 2013

slide-5
SLIDE 5

9/6/2014 5

CCR UCSF center for cerebrovascular research

AVM vessels have less pericyte coverage

Chen et al. ATVB, 2013

CCR UCSF center for cerebrovascular research

Microhemorrhage

Chen et al. ATVB, 2013

CCR UCSF center for cerebrovascular research

ALK1 Knockdown Attenuates the Upregulation of PDGFB in HBMEC in Response to VEGF Stimulation

HBMEC (human brain microvascular endothelial cell) were transfected with control shRNA or shRNA . Cells with >70% reduction of Alk1 gene expression were cultured for 18 h in the presence or absence of VEGF (0, 10, 50, and 100 ng/ml). qRT-PCR was performed for Alk1 (A) and Pdgfb (B). All data are shown as mean and SD. *p<0.05 vs. control.

B

1 2 3 4 5 Pdgfb mRNA Fold Change

Control shAlk1 VEGF 0 10 50 100 (ng /ml)

* * *

0.5 1 1.5 2 2.5 3

Alk1 mRNA Fold Change

Control shAlk1

A

VEGF 0 10 50 100

(ng /ml)

* * * *

CCR UCSF center for cerebrovascular research

ALK1 knockdown in HBMEC impairs the pericyte recruitment

20 40 60 VEGF + shAlk1 shAlk1 VEGF Control Average Pericyte Distance µm

A B

* *

slide-6
SLIDE 6

9/6/2014 6

CCR UCSF center for cerebrovascular research

50 µm

Gene Mutation in Bone Marrow Transmits the Phenotype

CCR UCSF center for cerebrovascular research

Reduction of Gene Mutant Endothelial Cell Reduced GI Hemorrhage and Mortality

CCR UCSF center for cerebrovascular research

BMDC/Monocyte Inflammation Angiogenesis

Therapies

Anti-angiogenesis (bevacizumab, sFLT) BM or monocyte transfusion Anti-inflammation (tetracycline class)

Important Factors in AVM Pathogenesis

Impaired mural cell recruitment Improve vascular integrity (Thalidomide,Lenalidomide)

CCR UCSF center for cerebrovascular research

Anti-Angiogenesis

Bevacizumab reverse brain AVM phenotype

Walker et al. Stroke, 2012

slide-7
SLIDE 7

9/6/2014 7

CCR UCSF center for cerebrovascular research

Anti-Angiogenesis

Stereotactic Injection of AAV2-sFLT Inhibited Brain AVM Formation

AAV2-EV AAV2-sFLT02

  • 1. Block VEGF that is used for model induction
  • 2. Invasive intra-brain injection

CCR UCSF center for cerebrovascular research

Developmental onset

  • 1. SM22α-Cre mediated Eng deletion
  • 2. 95% mice have brain AVM at five weeks of age
  • 3. Brain AVM in this model was developed spontaneously without local

angiogenic stimulation

  • 4. About 30% mice died between 3 and 6 weeks

Choi et al., PLOS One, 2014

CCR UCSF center for cerebrovascular research

number motality paralyzed final mice number AAV9-GFP 9 3 1 5 AAV9-sFLT 8 2 6

Intravenous Injection of AAV9-sFLT Reversed Brain AVM Phenotype

SM22αCre;Engf/f mice

  • 1. 1X1011 vg AAV9-sFLT

IV to 5 weeks old mice.

  • 2. Samples were collected

4 weeks later

  • 1. AAV-sFLT reverse brain AVM phenotype
  • 2. Systemicdelivery of AAV-sFLT is feasible
  • 3. AAV-sFLT is effect on spontaneous

developed bran AVM

CCR UCSF center for cerebrovascular research

Lebrin, et al, Nat Med 16: 420, 2010

Increase PDGFB

slide-8
SLIDE 8

9/6/2014 8

CCR UCSF center for cerebrovascular research

Increase PDGFB

Thalidomide Treatment Reduced the Number of Abnormal Vessels

CCR UCSF center for cerebrovascular research

Increase PDGFB

Thalidomide Treatment Reduced Microhemorrhage

CCR UCSF center for cerebrovascular research

Summary

  • 1. Invasive therapies are associated with considerable risks
  • 2. No specific medical therapy is available
  • 3. The concept for the treatment of brain AVM is to

stabilize vascular tissue and thereby decrease the risk of spontaneous ICH.

  • 4. Novel therapeutic approaches:
  • A. Anti-inflammation
  • B. Anti-angiogenesis
  • C. Improve vascular integrity
  • D. Correct gene mutation in BM monocyte/progenitors

CCR UCSF center for cerebrovascular research

Thank You

William L. Young Mervyn Maze Helen Kim Ludmila Pawlikowska Michael T. Lawton Charles E. McCulloch Funding: NIH AHA Michael Ryan Zodda Foundation Espen Walker Wanqiu Chan Eunjung Choi Fanxia Shen Yi Guo Lei Mao Marine Camus Mamta Wankhede Zhengyi Han Yue He Cameron McDougall Liang Wang Lei Zhan Shuai Kang Wan Zhu Rui Zhang Dingquan Zou