Stem cell therapy in cardiac practice
Dr Sajeer K T
Senior resident,
Department of Cardiology,
Govt. Medical College,
Kozhikode.
1
Background
 Cardiovascular disease ➔ leading cause of morbidity and mortality
worldwide
 Despite advances in Mx and cath-based therapy for AMI
 1-year mortality: 13%
 5-year prognosis for patients with HF: 50%.
 LV systolic dysfunction:
 major determinant of prognosis
 associated with significant loss of cardiomyocytes
(Irreversible ➔heart post mitotic organ)
Abdul M. Mozid et al. British Medical Bulletin 2011; 98: 143–159
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Stem cell therapy
 Clinical trials focused on 3 main situations:
 Acute MI (with the hope of preventing LVSD)
 Chronic heart failure secondary to previous MI
 DCM (non ischemic cardiomyopthy)
 Areas of discussion:
1. Stem cell types used in cardiac repair
2. Methods of cell delivery in clinical practice
3. Clinical trial evidence to date
3
Stem cell ?
 Stem cell
 a cell with a unique capacity to produce
unaltered daughter cells (self-renewal) & to
generate specialized cell types (potency)
 Self-renewal
 symmetric division:
 two stem cells
two cells destined for differentiation
 asymmetric division:
 one stem cell and one differentiating cell
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Signature characteristic of the stem cell
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Types of stem cells
Stem cells : 2 types
 Somatic stem cells :
 BM, brain, liver, skeletal & dermal tissue
 in vitro proliferative ability is limited
 Pluripotent stem cells :
 Embryonic stem cells, embryonic germ cells
embryonic carcinoma cells, induced pluripotent stem (iPS)
 Exhibit pluripotency
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Traditional view
➲
Current evidence
Traditional view:
 heart is a terminally differentiated post mitotic organ
 Current evidence:
 heart is not a terminally differentiated post mitotic organ
 4 sources of cells : for new cardiomyocytes after birth
1. Adult cardiomyocytes (mononucleated)
2. Bone marrow–derived cardiac stem or progenitor cells
3. Embryonic epicardium derived cells
4. Niches of cardiac stem or cardiac progenitor cells (CPCs)
Stem Cells 2007; 25:589.
Cell 2009 138;257–270.
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Different cell types investigated for use in cardiac repair
Abdul M. Mozid et al. British Medical Bulletin 2011; 98: 143–159
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Heart - self-renewing organ
 Myocyte regeneration occurs throughout organism lifespan
 Cardiac niches contain stem cells ➔ after activation
➔ give rise to myocytes and vascular structures
Piero Anversa, Jan Kajstura, Annarosa Leri. Circulation. 2006;113:1451-1463 9
Cardiac Stem or Progenitor cells (CSC or CPC)
 niche of primitive cells present in human heart
 possess the ability to form cardiomyocytes, endothelial cells
(ECs), smooth muscle cells (SMCs)
Different classes of CPCs : based on cell surface markers
1. c-Kit+ cells
2. Sca-1+ cells
3. side population cells (SP)
4. cells expressing the protein Islet-1 (transcription factor)
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Cardiac progenitor cell classes
 c-kit positive cell
 Sca-1 positive cell
 SP cells
 Cardiospheres
 Epicardial progenitors
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Hierarchy of CPC growth and differentiation
 Asymmetrical division of a CSC ➨ a daughter
CSC and a daughter cardiac progenitor (CPg)
 CPg gives rise to
- Myocyte progenitor (MPg )& precursor (MPr)
- EC progenitor (EPg) & precursor (EPr)
- SMC progenitor (SMPg) & precursor (SMPr)
 Precursors ➨ transient amplifying cells ➨ divide
and differentiate into mature myocytes, ECs, and
SMCs.
 CSCs are lineage-negative cells : express only
c-kit, MDR1, or Sca-1.
 Progenitors express stem cell antigens and
transcription factors of cardiac cells but do not
exhibit specific cytoplasmic proteins
 Precursors possess stem cell antigens,
transcription factors, membrane& cytoplasmic
proteins typical of myocytes, ECs, and SMCs
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Hierarchy of CPC growth and differentiation
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Cardiac Stem Cells and Myocardial Diseases
 Role of cardiac stem cells in the advanced stages of HF:
- to modulate endogenous CPCs to regenerate cardiac muscle
and to create new blood vessel formation
 Ventricular remodeling ➔ progressive chamber dilation and thinning of the walls
 Myocardial regeneration ➔ reverse this process
➔ transforming a dilated failing heart into a normal, functionally
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competent organ
Bone marrow stem cells
 Bone marrow–derived stem cells:
- best studied cells
- used in clinical trials in MI and/or idiopathic DCM
 Bone marrow progenitor cells:
- hematopoietic stem cells (HSCs)
- side population cells (SP cells)
(expression of the Abcg2 transporter and allowing
export of Hoechst dye)
- mesenchymal stem cells (MSCs)
- multipotential adult progenitor cells (MAPCs)
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Inducible Pluripotent Stem Cells (iPSCs)
 Adult stem cells ➔ successfully reprogrammed back to an
undifferentiated pluripotent state
(by inserting 4 genes: Oct3/4, Sox2, KL4 and c-Myc into differentiated
somatic cells)
 Morphological phenotype of ES cells
 Same differentiation potential as ES cells ( in vivo and in vitro)
- able to form all three germ layers
 Functioning cardiomyocytes ➔ produced from iPSCs
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Inducible Pluripotent Stem Cells (iPSCs)
Generation of iPS cells
from somatic cells
Reprogramming factors ➨ introduced in vitro
Established iPS cells ➨ differentiate into various cell types
Circulation. 2010;122:80-87
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iPS demonstrate pluripotent features
Circulation. 2009;120:408-416
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Cell types and mode of delivery of cells for cardiac
repair
A : Cell types used for cardiovascular
repair
B: Delivery strategies used in the
clinical setting for cell therapy
EPCs = endothelial progenitor cells
iPS cells = induced pluripotent SCs
MSCs = mesenchymal stem cells
SP cells = side population cells
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Summary of cell types used in clinical trials and future perspective
Circulation. 2010;121:325-335
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Method of delivery of stem cells
 Intracoronary infusion of cells:
- most popular mode of cell delivery - after AMI
 Intramyocardial injection:
- performed in patients with chronic heart failure
secondary to IHD
- transendocardial injections (catheter-based)
- transepicardial injections (during open heart surgery)
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Mechanisms of action
Progenitor cells: improve functional recovery of infarcted or failing myocardium
1. Direct or indirect improvement of revascularization
2. Paracrine factors released by progenitor cells may inhibit cardiac apoptosis,
affect remodeling, or enhance endogenous repair (eg: by tissue-resident PCs)
3. Differentiation into cardiomyocytes may contribute to cardiac regeneration.
22
Homing of BM-derived stem cells to the
myocardium
 Homing of BM-derived stem cells to the myocardium:
- fate of bone marrow-derived stem cells is determined by the
microenvironment that they enter
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Mobilization and homing
Homing is mediated by :
 Adhesion
Transmigration
 Invasion
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Prerequisite for cell-based therapies
Summary of prerequisite for
cell-based therapies
Circulation. 2010;121:325-335
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Stem cell therapy in acute MI
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Stem cell therapy in acute myocardial
infarction
 Most of the trials used intracoronary delivery of BMSCs following
successful stenting of the infarct-related artery
 Surrogate markers used to assess efficacy of cell therapy:
- Improvements in the LVEF
- Reduction in size of scar tissue
- Reduction in cardiac volume
 Post infarction heart failure:
- results from ventricular remodeling processes
- characterized by progressive expansion of the infarct area and
dilation of the LV cavity
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 Major goal to reverse LV remodeling:
- enhancement of regeneration of cardiac myocytes
- stimulation of neovascul. within the infarct area
 4 main randomized controlled trials (RCTs)
- published with positive findings
1. TOPCARE-AMI
2. BOOST trial
3. REPAIR-AMI trial
4. FINCELL
( Circulation- 2002)
( Lancet - 2004)
( EJM
- 2006)
(Eur Heart - 2008)
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Randomized control trials of intracoronary BMSC therapy
following acute myocardial infarction
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TOPCARE-AMI :Transplantation of Progenitor Cells
and Regeneration Enhancement in AMI
Birgit Assmus et al. Circulation. 2002;106:3009-3017 30
LV Function Assessed by Analysis of LV Angiography in the
Cell Therapy Group
 Demonstrated potential beneficial effect of BSMC therapy following AMI
with improvement in the LVEF from 51.6+ 9.6% to 60.1+8.6% at 4 months
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TOPCARE-AMI :Transplantation of Progenitor Cells
and Regeneration Enhancement in AMI
Left panel (A):
LV angiography before
CPC therapy
Right panel (B):
at 4-month follow-up
Birgit Assmus et al. Circulation. 2002;106:3009-3017 32
TOPCARE-AMI :Transplantation of Progenitor Cells
and Regeneration Enhancement in AMI
Echocardiographic wall motion score index at rest (initial basal) and during low-dose
dobutamine stimulation (initial 10 g dobutamine) at baseline before progenitor cell therapy and
at rest at 4-month follow-up (follow-up basal).
Birgit Assmus et al. Circulation. 2002;106:3009-3017 33
TOPCARE-AMI :Transplantation of Progenitor Cells
and Regeneration Enhancement in AMI
Birgit Assmus et al. Circulation. 2002;106:3009-3017 34
BOne marrOw transfer to enhance ST-elevation infarct
regeneration (BOOST trial)
Lancet 2004; 364: 141–48
35
BOne marrOw transfer to enhance ST-elevation infarct
regeneration (BOOST trial)
Lancet 2004; 364: 141–48
36
BOne marrOw transfer to enhance ST-elevation infarct
regeneration (BOOST trial)
Lancet 2004; 364: 141–48
37
BOne marrOw transfer to enhance ST-elevation infarct
regeneration (BOOST trial)
Lancet 2004;
364: 141–48
38
BOne marrOw transfer to enhance ST-elevation infarct
regeneration (BOOST trial)
 Representative colour-coded
images showing systolic wall
motion at baseline and 6 months'
follow-up in two patients.
 Both patients had A/C AWMI.
 Bright colours: good systolic
wall motion.
 Dark colours : poor wall motion
(expressed in mm).
 Note improved functional recovery
in patient treated with BMCs.
Lancet 2004; 364: 141–48
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Reinfusion of Enriched Progenitor Cells
and Infarct Remodeling in Acute Myocardial Infarction
(REPAIR-AMI) trial
Enrollment and outcomes
N Engl J Med 2006;355:1210-21.
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Reinfusion of Enriched Progenitor Cells
and Infarct Remodeling in Acute Myocardial Infarction
(REPAIR-AMI) trial
N Engl J Med 2006;355:1210-21.
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Reinfusion of Enriched Progenitor Cells
and Infarct Remodeling in Acute Myocardial Infarction
(REPAIR-AMI) trial
Placebo n=92
BMC n=95
P value
N Engl J Med 2006;355:1210-21.
42
Reinfusion of Enriched Progenitor Cells
and Infarct Remodeling in Acute Myocardial Infarction
(REPAIR-AMI) trial
N Engl J Med 2006;355:1210-21.
43
Reinfusion of Enriched Progenitor Cells
and Infarct Remodeling in Acute Myocardial Infarction
(REPAIR-AMI) trial
Panel A:
Interaction between baseline LVEF and
the absolute change in LVEF
Panel B:
Interaction between the timing of
intracoronary infusion of BMC or
placebo after reperfusion therapy and
the absolute change in LVEF
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N Engl J Med 2006;355:1210-21.
Reinfusion of Enriched Progenitor Cells
and Infarct Remodeling in Acute Myocardial Infarction
(REPAIR-AMI) trial
Conclusion
 Intracoronary administration of BMC is associated with improved
recovery of left ventricular contractile function in patients with acute
myocardial infarction
N Engl J Med 2006;355:1210-21.
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Effects of I/C injection of mononuclear BMCs on LV function,
arrhythmia risk profile, and restenosis after lytic therapy of AMI
- FINCELL Investigators
Aim: To assess the efficacy and safety of bone marrow cell (BMC) therapy
after thrombolytic therapy of an acute STEMI
Methods: Patients with STEMI treated with thrombolysis followed by PCI
(2–6 days after STEMI )
Intracoronary BMCs (n= 40)
placebo medium (n= 40)
(collected & prepared 3–6 h prior PCI)
Injected into the infarct artery immediately after stenting
European Heart Journal (2008) 29, 2723–2732
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Effects of I/C injection of mononuclear BMCs on LV function,
arrhythmia risk profile, and restenosis after lytic therapy of AMI
- FINCELL Investigators
 Efficacy assessed by :
 measurement of global LVEF - LV angiography
- 2-D echo
 Safety by measuring arrhythmia risk variables
 Restenosis of the stented vessel by IVUS
At 6 months:
 BMC group : greater absolute increase of global LVEF than placebo
(measured by angiography or 2-D echo)
 No differences observed between the groups in
- adverse clinical events
- arrhythmia risk variables
- MLD of stented coronary lesion
European Heart Journal (2008) 29, 2723–2732
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Effects of I/C injection of mononuclear BMCs on LV function,
arrhythmia risk profile, and restenosis after lytic therapy of AMI
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Effects of I/C injection of mononuclear BMCs on LV function,
arrhythmia risk profile, and restenosis after lytic therapy of AMI
- FINCELL Investigators
Conclusion :
Intracoronary BMC therapy is associated with an
improvement of global LVEF and neutral effects on
arrhythmia risk profile and restenosis of the stented
coronary lesions in patients after lytic therapy of STEMI
European Heart Journal (2008) 29, 2723–2732
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RCTs with neutral findings
 LEUVEN-AMI study1:
- No changes in global LVEF after BMSC infusion
 ASTAMI trial2 :
- No significant effect on the LVEF, LV volumes, or infarct size
 HEBE trial3 :
- No changes in global or regional LV systolic function
after BMSC therapy
1Janssens
2
et al. Lancet 2006;367:113–21
Lunde K et al. N Eng J Med 2006;355:1199–209
3Alexander
Hirsch et al. Eur Heart J 2010
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Reasons for the inconsistent findings:
1. Variations in the number of cells delivered
2. Timing of delivery after AMI
3. Differences in the cell isolation protocol
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Stem cell therapy in chronic
ischemic heart failure
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Stem cell therapy in chronic ischemic heart
failure
 Skeletal myoblasts and BMSCs : 2 cell types investigated in chronic
heart failure & severely impaired LV function
secondary to previous MI
 Skeletal myoblasts transplantation:
: initially investigated in patients undergoing
open heart surgery
 Myoblasts are obtained from culture of a prior muscle biopsy
 Injected in to epicardium at the time of surgery
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Clinical trials of stem cell therapy for chronic
ischemic heart failure
Clinical trials of stem cell therapy for chronic ischemic
heart failure
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The Myoblast Autologous Grafting in Ischemic Cardiomyopathy
(MAGIC) Trial
 1st randomized placebo-controlled
study of Myoblast transplantation
 Patients with LVSD secondary to
previous MI and who required CABG
 Cells ➔ injected into epicardium
within scarred areas during open heart
surgery
Circulation. 2008;117:1189-1200
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The Myoblast Autologous Grafting in Ischemic Cardiomyopathy
(MAGIC) Trial
Circulation. 2008;117:1189-1200
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The Myoblast Autologous Grafting in Ischemic Cardiomyopathy
(MAGIC) Trial
A : Time to first MACE
B: Time to first ventricular arrhythmia
 study was prematurely stopped
 no improvement in regional or global
LVEF
 higher number of arrhythmic events
Circulation. 2008;117:1189-1200
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STAR-heart study
The acute and long-term effects of intracoronary Stem cell Transplantation
in 191 patients with chronic heARt failure: the STAR-heart study
 only limited data available on the effectiveness of BMC’s in chronic HF
 largest study to date of BMSC therapy in chronic ischaemic HF
 investigated ventricular hemodynamics, geometry, and contractility as
well as the long-term clinical outcome of BMC treated patients with
reduced LVEF due to chronic ischaemic cardiomyopathy
Bodo-Eckehard Strauer et al. European Journal of Heart Failure (2010) 12, 721–729
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STAR-heart study
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STAR-heart study
Bodo-Eckehard Strauer et al. European Journal of Heart Failure (2010) 12, 721–729
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STAR-heart study
EF over time in the BMC group
compared with the control group
Bodo-Eckehard Strauer et al. European Journal of Heart Failure (2010) 12, 721–729
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STAR-heart study
Effect of BMC therapy on survival in patients with chronic ischaemic cardiomyopathy
Bodo-Eckehard Strauer et al. European Journal of Heart Failure (2010) 12, 721–729
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STAR-heart study
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STAR-heart study-conclusion
 5-year follow-up
 intracoronary BMSC therapy ➔ associated with significant
improvement in the LVEF and exercise capacity
 significant decrease in long-term mortality
Bodo-Eckehard Strauer et al. European Journal of Heart Failure (2010) 12, 721–729
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Stem cell therapy in
dilated cardiomyopathy
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Stem cell therapy in dilated
cardiomyopathy
TOPCARE-DCM
Transplantation of Progenitor Cells and Functional Regeneration
Enhancement Pilot Trial in Patients with Non-ischemic DCM
A Pilot Trial :
to assess potential effects of selective intracoronary bone marrow–
derived progenitor cell infusion in patients with non-ischemic DCM
Intracoronary administration of BMCs ➔ shown to improve coronary micro
vascular function in IHD
Coronary micro-vascular dysfunction is implicated in the pathogenesis and
prognosis of noni-schemic DCM
Ulrich Fischer-Rasokat et al. Circ Heart Fail. 2009;2:417-42366
TOPCARE-DCM
Individual changes of the extent of hypokinetic area (A), severity of
hypokinesia (B), and ejection fraction (C) between baseline and 3-month
follow-up
67
TOPCARE-DCM
Conclusion:
Intracoronary administration of
BMC seems to be associated
with improvements in cardiac
contractile and micro vascular
function in patients with DCM
Individual changes of the adenosine-induced minimal vascular resistance
index of the BMC-treated LAD for all 24 patients between baseline and 368
month follow-up
Summary and future directions
 Past decade has seen an explosion in clinical studies investigating the
safety and efficacy of stem cell therapy for heart diseases.
 Safety of stem cell therapy has been demonstrated uniformly in the
vast majority of the studies.
 Beneficial effects of cell therapy have been demonstrated
: AMI, chronic ischaemic HF and DCM.
 Need for larger RCTs with longer term follow-up assessing morbidity
and mortality as primary outcome measures.
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