Disclosure Upstream Therapy for Grant Atrial Fibrillation Zoll - - PowerPoint PPT Presentation

9/7/2012 1

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San Francisco General Hospital

San Francisco VA Medical Center

Medical Center

Heart & Vascular Center

UC SF

Cardiovascular Research Institute

Gladstone Institute

• f Cardiovascular Disease

Upstream Therapy for Atrial Fibrillation

CA Heart Rhythm Symposium September 2012 Jeffrey Olgin, MD Chief, Division of Cardiology Co-Director, Heart and Vascular Center University of California San Francisco

Disclosure

Grant Zoll Grant/Honorarium Gilead Syllabus

• What does upstream mean?
• Evidence for role of fibrosis in AF
• Biology of fibrosis
• EP Effects of fibrosis
• Mechanism of fibrosis in AF
• Atrial selectivity of fibrosis
• Potential therapies

Common AF: An Acquired Disease

Genetic Influences Environmental Influences Other Diseases

(HTN, CHF, OSA, obesity)

REMODELING

Electrical Structural Neuro-humoral

ATRIAL FIBRILLATION

Trigger Substrate Aging

9/7/2012 2 AF: Current Treatment

Genetic Influences Environmental Influences Other Diseases

(HTN, CHF, OSA, obesity)

REMODELING

Electrical Structural Neuro-humoral

ATRIAL FIBRILLATION

Trigger Substrate Aging

Ablation AA Drugs Disease Rx

What is Does Upstream Mean?

Genetic Influences Environmental Influences Other Diseases

(HTN, CHF, OSA, obesity)

REMODELING

Electrical Structural Neuro-humoral

ATRIAL FIBRILLATION

Trigger Substrate Aging

UPSTREAM

ACEI/ARB/ALDOI Use to Prevent AF

Khatib, et al. Int J Cardiol 2012

ACEI/ARB Use to Prevent AF

Khatib, et al. Int J Cardiol 2012

9/7/2012 3 Statin Use to Prevent AF

Fang, et al. Br J Clin Pharm 2012

Fish Oil: Afib Recurrence after CV

Kowey, et al. JAMA 2010

~7 day load

Kumar, et al. Heart Rhythm 2012

4-8 week load

Up a Creek Without a Paddle:

Anti-arrhythmic Drugs

Exploiting Gaps in the Market

9/7/2012 4 Fibrosis as Final Common Pathway

• Senescence
• Mitral valve disease
• HTN
• Heart Failure
• Lone AF

Atrial Fibrillation and Fibrosis

Boldt Heart 2004 Aimé-Sempé JACC 1999 Kostin Card Res 2002

Lone CAF

Sirius Red Collagen IH

Sinus Rhythm

Collagen IH Trichrome

Atrial Fibrillation and Fibrosis: LA

Boldt, et al. Heart 2004

Lone AF Mitral Valve Disease

LONE Parox AF LONE Chronic AF MVD Parox AF MVD Chronic AF MVD SR SR

Collagen Content

(collagen/GADPH)

Fibrosis in LA: Lone AF

Marcus, et al. Heart Rhythm 2007

9/7/2012 5

Heart Failure Induced Atrial Remodeling

Li, et al Circulation 1999

CTL RAP CHF CTL RAP CHF

Duration (sec) Fibrosis AF Duration

TGF-ß1 Transgenic Mouse

Verheule, et al. Circulation Res 2004

AF Inducibility

Verheule, et al. Circ Res 2004

0% 20% 40% 60% 80% 100%

Wt Tx

% AF

p < 0.001 41/53 1/48

TGFß1 Mice: Cellular Electrophysiology

Verheule, et al. Circ Res 2004

9/7/2012 6

TGFß1 Mice: Conduction

Verheule, et al. Circ Res 2004

The Heart: Not Just Cardiomyocytes

Myocyte Lymphocyte Endothelial Cell Fibroblast

Cytokines ROS Cytokines Cytokines ROS Cytokines

Cardiac Cell Subpopulations

Cardiac Fibroblasts

• Make up about 50-60% of cell types in the heart

– Higher in the atria

• Responsible for maintaining the extracellular

matrix in the heart

– Collagen turnover—about 5% per day – Integrates contractile force across cardiomyocytes – ECM conserves 3-dimensional cyto-architecture for efficient conduction and contraction

• Can transform to collagen & cytokine producing

“factories” called myofibroblasts

• Can actively and passively exert electrical

effects

Fibroblast Transformation

• Fibroblast exist as small, round cells that have

low level of collagen production

• When stimulated they begin to express large

quantities of actin and become factories for collagen and cytokines

– Stimulated by stretch, cytokines, injury, stress

Fibroblast Myofibroblast Transformation

Collagen

Collagen

Cytokines Ion Channels

9/7/2012 7 Active and Passive Effects of MFb

PROPAGATION

• Secrete Collagen—insulator
• Larger size and coupling

– Couple to CMyocyte via Connexin – Passive conductor across MFb – Electrotonic interaction with Cmyocyte

IMPULSE GENERATION

• Collagen improves source—sink for

automaticity (like sinus node)

• MFb ion channel expression and coupling to

Cmyocyte

– Spontaneous depolarization and automaticity

What does fibrosis do?

• Slows conduction (regional)
• Fibrillatory conduction/wavebreak
• Substrate for rotors
• Facilitates automaticity

Isotropic Conduction Non-Uniform Anisotropy

9/7/2012 8 Conduction Heterogeneity

Normal AF Substrate

Verhuele, et al AJP 2004

Effects of MFb

Propagation Automaticity

Rohr, Heart Rhythm 2009

• What is the mechanism of atrial

fibrosis?

• Does preventing fibrosis prevent

atrial fibrillaiton? Mechanism of Atrial Fibrosis

adapted from Burstein & Nattel, JACC 2008

Heart Failure

Cytokines Mechanical Stretch Atrial Myocyte Fibrolast

Collagen & ECM

ROS Catechol TGFß Activation

9/7/2012 9 Canine Heart Failure: TGFß

Lee, et al. Circulation 2006

Atrial TGFß1 Expression

Human Atria: TGFß1 Levels

hTGF-β1 β-actin

No AF Incident AF All AF p<0.0001 p=0.0017 Relative Protein Level ( Folder Changes) AF C C AF C AF C AF AF C C C C AF C C C

a b

HF Model of AF

Effect of Pirf on Fibrosis

Lee, et al. Circulation 2006

Effect of Pirfenidone

Lee, et al. Circulation 2006

Conduction AF Vulnerability

9/7/2012 10

Effect of Pirf on AF Substrate

Lee, et al. Circulation 2006

TGFß1 Expression

• Why is the atria uniquely

susceptible to fibrosis? TGFß1 Mice: Selective Atrial Fibrosis

W t A W t V T x A T x V Sirius red staining (%) §

§ p<0.0001

Recovery from Heart Failure

, et al. Circulation 2004 Cha, et al. Circulation 2004

9/7/2012 11

Differential Fibrosis:

Canine HF

Hanna, et al. Cardiovasc Res 2004

TGFß1 Tx Mice:

Differential Gene Expression

Log2 (TxV/WtV) Significant difference TxA vs WtA Significant difference TxV vs WtV Log2 (TxA/WtA)

Atria (Wt) Atria (Tx) Ventricle (Tx) Ventricle (Wt) MEEBO Array

TGFß Signaling

[Modified from Derynk] —

TGFß Signaling

[Modified from Derynk] — — Atrial Specific

9/7/2012 12 Rescue of TGFß Overexpression

5 10 15 20 25 30 35 RA LA % FIBROSIS Wt TGF Tx TGF Tx/NPRC KO Wt TGF Tx TGF Tx/NPRC KO

• Is this relevant to human atrial

fibrillation? TGFß1 Content: Human Hearts

Non-Failing Failing

TGFß1 GAPDH

ATRIUM VENTRICLE

TGFß1 GAPDH

p<0.0001 p<0.0001 Relative Protein Level ( Fold Changes) p=0.6

ATRIUM VENTRICLE

Chamber Differences in Fb

Colagen Lox

TGFß1

qRT-PCR Failing or Non-Failing Human Hearts Cell Isolation Fb Culture Ventricle Atria IHC Actin Morphology

9/7/2012 13

ctrl tgfb1 ctrl tgfb1 2 4 6 8 ctrl tgfb1 ctrl tgfb1

Isolated Human Fibroblasts:

Response to TGFß1

Atrial Fb Atrial Fb Ventricle Fb Ventricle Fb

Non-Failing Hearts Failing Hearts

Fold Change

Collagen I mRNA

Conclusion

Atrial fibrosis is an important substrate for AF TGFß1 plays a central role in animal models and human AF The atria are uniquely susceptible to TGFß- induced AF, especially in failing hearts Targeting fibrosis may be important target for prevention and treatment of AF—a new anti- arrhythmic approach

Swimming Upstream Swimming Upstream

9/7/2012 14 Thank You

Olgin Lab

Emily Wilson Dolkun Rehemedula Chunhua Ding Tom Everett Hoa Zhang Roger Chang George Hulley

Greg Marcus UCSF Microarray Core

David Erle Andrea Barczak Yuanyuan Xiao Anges Paquet

UCSF Living Heart Team

Roger Chang Croft Thomas Jacob Vogan

CTDN

54

Effect of Increasing Fibrosis

Simulated Tissue Propagation

Increasing Fibrosis

Jacquamet & Henriquez Heart Rhythm 2009

Rotor Driving AF

9/7/2012 15 ACE Inhibition in AF: CHF

Li, et al. Circulation 2001

100 200 300 400 500 600 700

Duration AF

Con VTP VTP+ Enal VTP+ H/I Duration of AF (min)

Up-a-creek Isolated Human Fibroblasts:

Response to TGFß1

Atrial Fb Atrial Fb Ventricle Fb Ventricle Fb

Non-Failing Hearts Failing Hearts

Fold Change

LOX mRNA

1 2 3 4 5

ctrl tgfb1 ctrl tgfb1 ctrl tgfb1 ctrl tgfb1

Human Atria: Activated TGFß1

500 1000 1500 2000 2500 3000 3500 4000 4500

control tgf-b1 tgf-b Ab tgf-b1+Ab non-AF non-AF+Ab AF AF+Ab

Luciferase Activity

PAI1-Luc Activity in MLEC Assay

p=0.002

PAI1

MLEC-PAI-Luc Tissue

9/7/2012 16 TGFß1 Tx Mice:

TGFß Signaling

pSmad-2 Smad-2/3 β-actin TGFβRI TGFβRII WtA TxA WtV TxV

ACEI for AF Prevention: Meta Analysis

Healey, et al. JACC 2005

TGFß Tx Mice:

Effect of TGFR Kinase Inhibition

100 200 300 400 500 600

Collagen-I mRNA levels (% WtA) WtA TxA TxA+Ki26894 TxV TxV+Ki26894 WtV

a

§ * * * *! * * * *! §

sf

gh

San Francisco General Hospital

San Francisco VA Medical Center

Medical Center

Heart & Vascular Center

UC SF

Cardiovascular Research Institute

Gladstone Institute

• f Cardiovascular Disease

AP-1 Regulated Genes

5 10 15 20 25 30 Wt A Tx A Wt V Tx V

IL-6

mRNA (fold difference from WtA)

Wt A Tx A Wt V Tx V

ET-1

Wt A Tx A Wt V Tx V

PAI-1

IL-6 ET-1 PAI-1 q-RTPC

W t ( V ) – W t ( A ) T x ( A ) – W t ( A ) T x ( V ) – T x ( A ) T x ( V ) – W t ( V )

9/7/2012 17 TGFß Tx Mice:

Effect of TGFR Kinase Inhibition

100 200 300 400 500 600

Collagen-I mRNA levels (% WtA) WtA TxA TxA+Ki26894 TxV TxV+Ki26894 WtV

a

§ * * * *! * * * *! §

Sinus Node: Trichrome Stain

Fibrosis required to

– Minimize electrotonic interaction for impulse generation – Overcome source-sink mismatches to allow SN to drive atria

Sanchez-Quintana, et al. Heart 2004

Genetic Influences Environmental Influences Other Diseases

(HTN, CHF, OSA, obesity)

REMODELING

Electrical Structural Neuro-humoral

ATRIAL FIBRILLATION

Trigger Substrate Aging

Ovine HTN Model Atrial Fibrosis

Control Hypertensive

Atrial Collagen Content

HTN CTRL

100 200 300 400

CTRL HTN

AF Duration (Sec)

Kistler et al. Eur Heart J 2006 AF Inducibility

9/7/2012 18 Effect of TGFß1 on Fibroblasts

Fibroblasts Myofibroblasts

Collagen Effect of TGFß1 on Fibroblasts

Fibroblasts Myofibroblasts

Collagen

Pirfenidone ✕ ✕ ✕ ✕ ✕ ✕ ✕ ✕

Effects of TGFß1

• Major activator of fibroblasts to

produce collagen

• Organ and vascular development
• Bone turnover
• Wound healing
• Cancer?

Cardiac Effects of TGFß1

• Hypertrophy
• Fibrosis
• Apoptosis

9/7/2012 19 Varied TGFß1 Effects

• Different receptor subtype

combinations

• Extracellular modifiers of TGFß

activity and receptor binding

• “Co-factors”
• Different intracellular signaling
• Coordination with other cytokines

and transcription factors

10 20 30 40 50 60 70 80 90 100 Wt Tx AF Inducibility (%) P<0.001

Wt RA

x

1 2 3 4 5 msec

x

1 3 5 7 9 msec Tx RA LA LA LV LV 2 6 10 14 18 msec 2 6 10 14 18 msec

A B C

Effective Refractory Period

LA LV

Wt Wt Tx Tx

msec

20 40 60 80 100 1 1 AF Inducibility

WtA 100 50 msec TxA 100 50 msec WtV 100 50 msec TxV msec 100 50

D

Representative Optically-Derived Action Potentials Activation Isochronal Maps

TGFß1 Activation

LAP-dimer Extracellular Matrix LTBP-1

Latency Associated Peptide

TGF-ß TGF dimer Small Latent Complex Large Latent Complex

TGFß1 Activation

LAP-dimer Extracellular Matrix LTBP-1

Latency Associated Peptide

TGF-ß

Active TGFß1 Activation MMP Integrin αvβ6

9/7/2012 20 Tx Mice: cys33ser TGFß1

LAP-dimer Extracellular Matrix LTBP-1

Latency Associated Peptide

TGF-ß

X Constituitively Active TGFß1

CHF and Atrial Fibrosis

Sanders, et al. Circulation 2003

Conduction Velocity (m/s)

HF Contr

Non-uniform Anisotropy