Download Translation of Human-Induced Pluripotent€Stem Cells

JOURNAL OF THE AMERICAN COLLEGE OF CARDIOLOGY
VOL. 67, NO. 18, 2016
ª 2016 BY THE AMERICAN COLLEGE OF CARDIOLOGY FOUNDATION
ISSN 0735-1097/$36.00
PUBLISHED BY ELSEVIER
http://dx.doi.org/10.1016/j.jacc.2016.01.083
THE PRESENT AND FUTURE
STATE-OF-THE-ART REVIEW
Translation of Human-Induced
Pluripotent Stem Cells
From Clinical Trial in a Dish to Precision Medicine
Nazish Sayed, MD, PHD,a,b,c Chun Liu, PHD,a,b,c Joseph C. Wu, MD, PHDa,b,c
ABSTRACT
The prospect of changing the plasticity of terminally differentiated cells toward pluripotency has completely altered the
outlook for biomedical research. Human-induced pluripotent stem cells (iPSCs) provide a new source of therapeutic
cells free from the ethical issues or immune barriers of human embryonic stem cells. iPSCs also confer considerable
advantages over conventional methods of studying human diseases. Since its advent, iPSC technology has expanded with
3 major applications: disease modeling, regenerative therapy, and drug discovery. Here we discuss, in a comprehensive
manner, the recent advances in iPSC technology in relation to basic, clinical, and population health.
(J Am Coll Cardiol 2016;67:2161–76) © 2016 by the American College of Cardiology Foundation.
S
Listen to this manuscript’s
ince the initial discovery that bone marrow
either adult stem cells or ESCs based on their origins
cells possess regenerative capacity through
and differentiation potentials. The unusual capacities
clonal expansion, which laid the foundation
of ESCs to proliferate without senescing (i.e., self-
for the field (1), regenerative medicine has come a
renewal) and to form all cell types of the embryo
long way. As a type of stem cell, these bone marrow
(i.e., pluripotency) made them unique and valuable
cells have the capacity for both self-renewal and dif-
resources for studying cell fate and tissue develop-
ferentiation into different cell types. Earlier attempts
ment. Initially, work on pluripotent stem cells
to understand the pluripotency of the inner cell mass
(PSCs) was conducted using human ESCs (5); howev-
focused on the developmental capacity of nuclei by
er, the requirement to destroy early-stage embryos
cloning in frogs (2), cloning in adult mammalian cells
in the process of ESC derivation made their use ethi-
(3), derivation of mouse and human embryonic stem
cally controversial. In addition, practical consider-
cells (ESCs) (4,5), and generation of ESCs and somatic
ations hindered their medical applications, because
cell fusion (6). Similarly, MyoD, a mammalian tran-
any cells or tissues generated from human ESCs by
scription factor, was found capable of converting
definition would be allotransplants into the recipient
fibroblasts to myocytes, which led to the concept of
patient, requiring possible life-long immunosuppres-
master regulators, transcription factors that deter-
sion therapy.
mine lineage specification (7). Using these paradigms,
The discovery by Takahashi et al. (8,9) that a small
subsequently discovered stem cells were classified as
set of reprogramming factors (e.g., Oct4, Sox2, Klf4,
From the aStanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, California; bInstitute for Stem Cell
audio summary by
Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, California; and the cDepartment of Med-
JACC Editor-in-Chief
icine, Division of Cardiology, Stanford University School of Medicine, Stanford, California. This work was supported by the Na-
Dr. Valentin Fuster.
tional Institutes of Health (NIH; R01 HL126527, NIH R01 HL123968, NIH R01 HL128170, and NIH R01 HL130020) to Dr. Wu, and by
an American Heart Association scientist development grant (13SDG17340025), NIH-National Heart, Lung, and Blood Institute
Progenitor Cell Biology Consortium pilot grant (SR00003169/5U01HL099997), and a Stanford Cardiovascular Institute seed grant
to Dr. Sayed. Dr. Wu is cofounder of Stem Cell Theranostics; and has received a research grant from Sanofi. All other authors have
reported that they have no relationships relevant to the contents of this paper to disclose.
Manuscript received November 20, 2015; revised manuscript received January 26, 2016, accepted January 26, 2016.
2162
Sayed et al.
JACC VOL. 67, NO. 18, 2016
MAY 10, 2016:2161–76
Human iPSCs for Precision Medicine
ABBREVIATIONS
and
nuclear
taking into account his or her unique genetic makeup
AND ACRONYMS
reprogramming of mouse (8) and adult hu-
(30). The goal is to understand the complex mecha-
man cells (9) to pluripotency became a land-
nism of diseases so that made-to-order treatment
mark development in regenerative medicine.
plans could be designed for each patient based on
Termed induced pluripotent stem cells (iPSCs),
their condition. In this review paper, we aim to
they promised a source of therapeutic cells
highlight the promise of iPSCs for expanding basic
free from the ethical issues or immune bar-
science research and generating novel therapeutic
riers of human ESCs while retaining similar
agents for clinical and public health applications.
CM = cardiomyocyte
EC = endothelial cell
ESC = embryonic stem cell
iPSC = induced pluripotent
stem cell
iPSC-CM = induced pluripotent
c-myc;
OSKM)
can
induce
properties, such as self-renewal and plurip-
stem cell–derived
cardiomyocyte
otency. Since that initial discovery, a number
PSC = pluripotent stem cell
of
advances
have
been
introduced
to
enhance both the efficiency of iPSC produc-
RPE = retinal pigment
tion and the safety of the resultant lines.
epithelial
These improvements include the use of
chemical agents to enhance efficiency (BIX-01294,
valproic acid, RG108, AZA [5-aza-2 0 -deoxycytidine],
dexamethasone, TSA [trichostatin A], and A-83-01)
(10,11), use of alternative cell sources for reprogramming (embryonic, fetal, and adult fibroblasts; neural
stem cells; adipose stem cells; keratinocytes; and
iPSC TECHNOLOGY: EMERGING CONCEPTS
The greatest hallmark of iPSC technology lies in its
simplicity and reproducibility. Although the past
decade has shown great improvement in making
iPSCs safer and more efficacious, which is critical for
pushing the technology toward clinical application,
the mechanisms involved in efficient generation of
iPSCs are just emerging. These evolving concepts
raise important fundamental questions that will be
discussed in the following sections.
blood cells) (12–14), use of various factors that could
HOW CAN A FEW TRANSCRIPTION FACTORS TURN
replace the reprogramming factors (15,16), use of
BACK THE CELLULAR CLOCK? Many studies have
vectors that can be excised from the genome (17,18),
tried to address this question, but the general
use of “nonintegrating” vectors (19,20), supplemen-
consensus is that the initial activity of the core plu-
tation
micro-
ripotency genes (OSKM) has a snowball effect that
ribonucleic acids (21), use of recombinant proteins/
results in simultaneous activation of the entire
peptides to reprogram somatic cells (22,23), and most
endogenous network of pluripotency genes and in-
recently, a purely chemical approach (24).
hibition of lineage-specific genes within the reprog-
of
reprogramming
factors
with
With the concerted efforts of the academic com-
rammed
somatic
cells.
The
initial
phase
of
munity, the past decade has seen a tremendous push
reprogramming is associated with cells undergoing
toward the efficient generation of safer PSCs, with the
metabolic changes and genome-wide alterations in
hope that one day iPSCs could be used for regenera-
histone marks and methylation, followed by a late
tive medicine in the clinic (25). Although halted
maturation phase that causes defined changes in
temporarily, the clinical trial using iPSC-derived
nuclear structure, the cytoskeleton, and signaling
retinal pigment epithelial cells (iPSC-RPEs) for treat-
pathways (31,32). Indeed, by looking closely at these
ment of macular degeneration shows how far we have
mechanisms, researchers can now obtain nearly per-
come in developing clinical-grade stem cells (26). In
fect iPSCs by clearing previous roadblocks to reprog-
the short run, iPSC technology will likely offer more
ramming (33).
avenues to understand the pathophysiology of dis-
ARE THESE iPSCs THE SAME AS ESCs? An important
eases and discover new therapeutic molecules. Spe-
question that comes up repeatedly is whether iPSCs
cifically, for disease modeling, iPSCs can be generated
have the same genetic and epigenetic landscape as
from patients who carry certain genetic mutations
ESCs, and whether differentiated cells (e.g., CMs)
and then differentiated into disease-relevant cell
from these 2 types of stem cells behave similarly.
types, such as cardiomyocytes (iPSC-CMs) (27–29).
Despite several previous studies suggesting differ-
Similarly, iPSC-derived cells can then be subjected to
ences in gene expression or deoxyribonucleic acid
high-throughput screens to discover new therapeutic
(DNA) methylation between iPSCs and ESCs (34–36),
small molecules or conduct drug toxicity assays.
the majority of iPSC and ESC clones are largely
Lastly, iPSC technology might enable personalized
indistinguishable (37–39). More recent reports sug-
therapies (i.e., cell or tissue replacement without the
gest that both cell types have identical molecular and
need for immunosuppression, and use of drugs
functional characteristics, with variations in their
tailored according to each patient’s genes, environ-
genetic backgrounds (i.e., different donors for iPSCs
ment, and life-style). This is precision medicine, an
and ESCs) accounting for most of their regulatory
initiative with the intent to cure each patient by
differences (40).
Sayed et al.
JACC VOL. 67, NO. 18, 2016
MAY 10, 2016:2161–76
COULD
Human iPSCs for Precision Medicine
TRANSDIFFERENTIATION
BE
THE
NEXT
variants that distinguish affected patients from
is
the
direct
unaffected subjects are located in noncoding regions
reprogramming of one somatic cell type to another
of the human genome with limited alignment to
desired cell type as an alternative approach to iPSCs.
genomes of animals used as model systems, we run
Termed transdifferentiation, this concept relies on
the risk that even after introducing the same human
the premise that we could achieve rapid reprogram-
genetic variant in the animal model, we might fail to
ming of a desired cell type by entirely avoiding the
recapitulate the human disease phenotype (49). Thus,
iPSC stage (41). Several groups have shown successful
there is a compelling need to model human diseases
transdifferentiation of fibroblasts to various types of
using human samples. Since the groundbreaking
STEP? Another
emerging
concept
somatic cells, such as neurons (42), hepatocytes (43),
creation of the first human iPSCs (9), many groups
CMs (44), and endothelial cells (45,46). However, a
have applied this technology to model human dis-
current major drawback to the use of direct reprog-
eases, with amyotrophic lateral sclerosis and various
ramming for clinical purposes is the tremendous dif-
congenital diseases among the first to be modeled
ficulty of obtaining sufficient numbers of target cells
using patient-specific iPSCs (12,50,51). Since these
that fully recapitulate the properties of the desired
reports, many have attempted to study human dis-
cells (47). In addition, transdifferentiation has thus
eases using iPSCs from patients with neurodegener-
far failed to generate a pure population of desired
ative
cells, which makes it difficult for them to be used for
(53–56), muscular dystrophies (57,58), and hemato-
diseases
(50,52),
cardiovascular
disorders
disease modeling and drug development (48). Simi-
logic disorders (59,60), to name a few. Cardiovascular
larly, in contrast to iPSCs, which once reprogrammed
diseases that have been studied are summarized in
can be easily maintained and differentiated to a
Table 1.
desired cell type, the transdifferentiation approach
M o d e l i n g a b r o k e n h e a r t : u s e o f i P S C s . Cardio-
would require restarting the entire reprogramming
myopathy is a complex disease of the heart that has a
process for each experiment.
pathogenesis that includes myocardial infarction,
APPLICATIONS OF iPSCs
genetic mutations, endocrine disease, and drug toxicities. Historically, animal models have been used to
understand the pathophysiology of cardiovascular
There are many human diseases that have limited
diseases and discover new therapeutics; however,
treatment options because of either a lack of relevant
because of significant differences in cardiovascular
tissue samples or a lack of information regarding
genetics and physiology between humans and ani-
disease progression. Thus, researchers traditionally
mals, there is a compelling need for more accurate
have relied on in vitro assays or animal models to
models to understand cardiac diseases. The ability to
understand disease progression and develop thera-
differentiate iPSCs to disease-relevant derivatives,
peutic interventions. These model systems use either
such as iPSC-CMs (27,77), now offers a valuable op-
small animals (e.g., rats and mice) or large animals
portunity to derive patient-specific cells for the pur-
(e.g., dogs, pigs, and nonhuman primates). These
pose of cardiac disease modeling and drug discovery
research designs are premised on the ability of the
(28,78).
animal model to mimic human subjects pathophy-
Human iPSC-CMs can serve as a disease model in a
siologically and to eventually develop end-stage dis-
dish by retaining the genetic variance present in the
ease like that seen in humans. However, because of
patient and eventually exhibiting the phenotypic
differences in cardiovascular anatomy and physi-
features of the disease in vitro. Indeed, several
ology (e.g., humans and rodents diverged w75 million
groups have used this iPSC-CM technology to model
years ago), animal models often do not accurately
cardiac channelopathies, such as long-QT syndromes
reproduce human pathophysiology in meaningful
(53–55,71,79,80), Timothy syndrome (73), LEOPARD
ways. Because iPSCs can be derived from healthy and
syndrome (51), catecholaminergic polymorphic ven-
diseased patients, they can be a robust alternative to
tricular tachycardia (81,82), arrhythmogenic right
animals for modeling human diseases (Figure 1).
ventricular dysplasia (74,83), familial hypertrophic
Indeed, several models of iPSCs have been generated
cardiomyopathy (62), and familial dilated cardiomy-
and explored for studying various human diseases, as
opathy (64–66). In addition to serving as an aid in the
outlined in the next section.
understanding of genetic cardiomyopathies, iPSC-
DISEASE
MODELING. The
inherent properties of
CMs have been used to model acquired or extrinsic
iPSCs for self-renewal and differentiation into any
cardiac diseases caused by endocrine, metabolic, and
cell type make them an ideal candidate for mo-
neuromuscular dysfunction. For example, iPSC-CMs
deling human diseases. Because many of the genetic
are being used in cell-based assays to model
2163
2164
Sayed et al.
JACC VOL. 67, NO. 18, 2016
MAY 10, 2016:2161–76
Human iPSCs for Precision Medicine
F I G U R E 1 Potential Applications of Patient-Specific iPSCs
Disease-specific target cells differentiated from patient-specific induced pluripotent stem cells (iPSCs) have 3 major applications: disease modeling, regenerative
therapies, and drug discovery/toxicity studies. iPSCs from patients with genetic mutations could be corrected via genome editing to yield healthy target cells for cell
therapy. Both corrected and uncorrected target cells could be used for disease modeling or drug screening. RBC ¼ red blood cells.
susceptibility to drug-induced cardiotoxicity (84,85),
indicate that they resemble fetal rather than adult
thereby allowing researchers to predict adverse drug
CMs. Structurally, compared with adult human CMs,
responses more accurately in patients with different
these iPSC-CMs look much smaller in size and have
genetic backgrounds. Similarly, iPSC-CMs have been
less sarcomeric organization with decreased force
used to understand the disease progression of dia-
generation (91–93). This could diminish their utility
betic cardiomyopathy (86), viral myocarditis (87),
for modeling adult-related heart diseases. Table 2
cardiac hypertrophy (88), and genetic polymorphism-
summarizes the differences between immature and
induced cardiac ischemia (89).
mature CMs.
Disease modeling using iPSC-CMs has been feasible
i P S C - C M s n e e d t o m a t u r e . In the developing heart,
because of ever-improving differentiation protocols
networks of diverse factors tightly regulate car-
(27,29,90). Importantly, although the phenotypic
diomyocyte maturation, including mechanical, elec-
characteristics of the iPSC-CMs are similar to those of
trical, and biochemical signals. Although relatively
primary human CMs with respect to their molecular,
simple expedients, such as keeping iPSC-CMs in cul-
electrophysiological,
ture for prolonged periods (97) or growing them on
properties,
these
mechanical,
functional
and
metabolic
characteristics
also
specific substrates (119), can enhance some aspects of
Sayed et al.
JACC VOL. 67, NO. 18, 2016
MAY 10, 2016:2161–76
their structure and function, much research now focuses on uncovering factors and pathways that drive
T A B L E 1 List of Cardiac Diseases Modeled With iPSCs
their maturation (120). Agents and cues that have
been explored to induce maturation include microRNAs (121,122), chromatin and histone proteins (123),
Disease
ments would be necessary to unravel the complexity
RYR2
Arrhythmia and abnormal
Ca2þ signaling
No
(61)
HCM
MYH7
Abnormal Ca2þ handling,
disorganized sarcomeres,
and electrophysiological
irregularities
No
(62)
DCM
LMNA
Nuclear senescence and
cellular apoptosis
No
(63)
TNNT2
Altered regulation of Ca2þ,
decreased contractility,
and abnormal distribution
of sarcomeric a-actinin
No
(64,65)
TTNtv
Sarcomere abnormalities,
impaired contractility and
response to stress
No
(66)
DES
Abnormal desmin aggregations,
aberrant Ca2þ handling,
and beating rate
No
(67)
PLN
Abnormal Ca2þ handling,
electrical instabilities,
and increased cardiac
hypertrophy markers
Yes
(68)
could potentially allow us to bring iPSC-CMs to
maturity in a dish, with closer resemblance to the
adult human heart. However, it is unlikely that cells
grown under in vitro conditions will fully resemble
cells residing in intact living subjects because of differences in environmental milieu, whether cardiac or
noncardiac. Hence, the expectation that iPSC-CMs
will be identical to mature primary human CMs
might be unrealistic.
iPSCs and genome engineering: a perfect match. The
MYBPC3
Contraction defects
No
(69)
BTHS
TAZ
Sarcomere assembly and
myocardial contraction
abnormalities
No
(70)
LQT1
KCNQ1
Prolonged duration of AP,
aberrant electrophysiological
Kþ current, and protective
action of beta-blockade
No
(71)
LQT2
KCNH2
Prolonged AP duration, reduced
cardiac potassium current
I (Kr), and increased
arrhythmogenicity
Yes
(54,55,71)
LQT3
SCN5A
Prolonged AP duration and
persistent Naþ current
No
(72)
LQT8
CACNA1C
Defects in Ca2þ signaling
and arrhythmia
No
(73)
ARVD
PKP2
Exaggerated lipogenesis,
desmosomal distortion
No
(74)
Pompe disease
GAA
Glycogen accumulation and
abnormal ultrastructure
Yes
(75)
FRDA
FXN
Impaired iron homeostasis,
mitochondrial damages
and aberrant Ca2þ signaling
No
(76)
LEOPARD syndrome
PTPN11
Abnormal cell size and
sarcomeric organization
No
(51)
finger nucleases, transcription activator–like effector
nuclease, and the clustered regularly interspaced
short palindromic repeat (128), has further advanced
the application of iPSC technology to precision
medicine. These genetic engineering techniques
allow for DNA to be inserted, replaced, or removed
from a genome by use of nucleases that create specific double-strand breaks at preferred locations.
Endogenous cellular mechanisms then repair these
breaks by homologous recombination (129). With
these tools, it is now possible to generate human
cellular disease models in a precise and predictable
manner. Indeed, genome editing has been used to
introduce genetic alterations to create cardiac disease
models or correct genetic mutations in iPSC-CMs to
model cardiac diseases. Single genetic mutations
responsible for cardiomyopathies, such as dilated
Barth
syndrome,
long-QT
(Ref. #)
(61)
of full cardiac maturation. Unraveling these pathways
emergence of genome editing tools, such as zinc
Gene
Correction
No
made in generating more mature iPSC-CMs. Additional future studies using high-throughput experi-
Features
Arrhythmia and abnormal
Ca2þ signaling
and biochemical cues (126,127). By decoding these
signaling pathways, substantial progress has been
Locus
CASQ2
CPVT
DNA methylation (124), metabolic energetics (125),
cardiomyopathy,
2165
Human iPSCs for Precision Medicine
syn-
drome, and Duchenne muscular dystrophy, have
been corrected by use of these genome-editing tools
(68,70,71,130,131), which suggests the feasibility of
this approach for disease modeling. However, these
AP ¼ action potential; ARVD ¼ arrhythmogenic right ventricular dysplasia; BTHS ¼ Barth syndrome;
Ca2þ ¼ calcium; CPVT ¼ catecholaminergic polymorphic ventricular tachycardia; DCM ¼ dilated cardiomyopathy;
FRDA ¼ Friedreich ataxia; HCM ¼ hypertrophic cardiomyopathy; iPSCs ¼ induced pluripotent stem cells;
Kþ ¼ potassium; LEOPARD ¼ lentigenes, electrocardiographic conduction defects, ocular hypertelorism, pulmonary stenosis, abnormalities of the genitals, retarded growth, and deafness or hearing loss; LQT ¼ long-QT
syndrome; Naþ ¼ sodium.
engineered nucleases could introduce unintended
genomic alterations; for example, in addition to
cleaving the on-target site, they might have off-target
REGENERATIVE MEDICINE. The use of PSCs, such as
effects. Similarly, other challenges, such as delivery
ESCs and iPSCs, for cell transplantation or organo-
methods and efficiency, still need to be sorted out
genesis has captured the imagination of the lay pub-
(132). Taken together, this tag-team technology of
lic, but it remains a difficult task to achieve from a
patient-specific iPSCs and genome editing could lay
scientific standpoint. The limitations of organ trans-
the groundwork required to achieve the bold initia-
plantation, which is plagued by lack of organ avail-
tive of precision health (30).
ability and problems with immunorejection, have led
2166
Sayed et al.
JACC VOL. 67, NO. 18, 2016
MAY 10, 2016:2161–76
Human iPSCs for Precision Medicine
T A B L E 2 Molecular, Electrophysiological, and Metabolic Profile of iPSC-CMs and Mature Cardiomyocytes
Parameters
Morphology
Immature CMs
Mature CMs
(Ref. #)
Shape
Round or polygonal
Rod and elongated
Size
20–30 pF
150 pF
(94)
(95)
Nuclei per cell
Mononucleated
w25% Multinucleated
(96)
Multicellular organization
Disorganized
Polarized
(95)
Sarcomere appearance
Disorganized
Organized
(95)
Sarcomere length
Shorter (w1.6 mm)
Longer (w2.2 mm)
(97)
(98)
Sarcomeric proteins
MHC
b>a
b >> a
Titin
N2BA
N2B
(99)
Troponin I
ssTnI
cTnI
(100)
Sarcomere units
Electrophysiology
Z-discs and I-bands
Formed
Formed
H-zones and A-bands
Formed (prolonged
differentiation)
Formed
(95)
M-bands and T-tubules
Absent
Present
Resting membrane potential
w60 mV
90 mV
(93)
Upstroke velocity
w50 V/s
w250 V/s
(101)
Amplitude
Small
Large
(95)
Spontaneous automaticity
Exhibited
Absent
(95)
Present
Absent
(101)
(102)
(97)
Action potential properties
Ion currents
Hyperpolarization-activated
pacemaker (If)
Sodium (INa)
Low
High
Inward rectifier potassium (IK1)
Low or absent
High
(101)
Transient outward potassium
current (Ito)
Inactivated
Activated
(103)
ATP-sensitive Kþ current (IK,ATP)
Not reported
Present
(104)
L- and T-type calcium
(ICa,L and ICa,T), rapid and
slow rectifier potassium
currents (IKr and IKs),
Naþ-Caþ exchange current
(INCX) and acetylcholine-activated
Kþ (IK,ACh)
Similar to adult CMs
(93)
Conduction velocity
Propagation of signal
Slower (w0.1 m/s)
Faster (0.3–1.0 m/s)
(105)
Gap junctions
Distribution
Circumferential
Polarized to
intercalated disks
(106)
Calcium handing
Ca2þ transient
Inefficient
Efficient
(107)
Amplitudes of Ca2þ transient
Small and decrease
with pacing
Increase with pacing
(108)
Excitation-contraction coupling
Slow
Fast
(109)
Contractile force
wnN range/cell
wmN range/cell
(110)
Low or absent
Normal
(111)
Positive
Negative
(112)
(113)
Ca2þ-handling proteins
CASQ2, RyR2, and PLN
Force-frequency relationship
Mitochondrial bioenergetics
Mitochondrial number
Low
High
Mitochondrial volume
Low
High
(113)
Mitochondrial structure
Irregular distribution,
perinuclear
Regular distribution,
aligned
(114)
Mitochondrial proteins
DRP-1 and OPA1
Responses to b-adrenergic stimulation
Low
High
(115)
Metabolic substrate
Glycolysis (glucose)
Oxidative (fatty acid)
(116)
Response
Lack of inotropic
reaction
Inotropic reaction
(117)
Cardiac alpha-adrenergic
receptor ADRA1A
Absent
Present
(118)
ATP ¼ adenosine triphosphate; CM ¼ cardiomyocyte; iPSCs ¼ induced pluripotent stem cells; MHC ¼ major histocompatibility complex.
Sayed et al.
JACC VOL. 67, NO. 18, 2016
MAY 10, 2016:2161–76
Human iPSCs for Precision Medicine
researchers to seek alternative approaches (9,15).
animals would be required to reach statistical power
Both ESCs and iPSCs could differentiate into any cell
and allow more in-depth mechanical analyses of the
type in the body and thus could potentially replace
engrafted heart, and the ventricular arrhythmias
diseased or dysfunctional cells. Advances in culturing
noted in these animals after transplantation must be
technology and differentiation protocols have pro-
addressed before human trials can be conducted
duced much safer and clinically relevant cells with
(148,149). In an effort to overcome the issues of poor
minimal tumorigenic risk (25). This enabled several
engraftment or survival of transplanted cells, another
groups to initiate clinical trials using PSCs, with most
study showed that a cytokine-loaded 3-dimensional
targeting eye diseases (26). Of the 13 clinical trials
fibrin patch with iPSC-derived cardiovascular cells
being conducted, 9 are for ESC-RPE or iPSC-RPE cells
(iPSC-CMs, iPSC-derived endothelial cells [ECs], and
for macular degeneration, which causes the progres-
iPSC-derived smooth muscle cells) had a better
sive deterioration of light-sensing photoreceptors in
chance of improving cardiac function in a pig model
the eye (133). Previous work had shown that iPSC-RPE
of myocardial infarction (146). One current clinical
and ESC-RPE cells were safe and functional in
trial is actively recruiting patients to test the use of
pre-clinical models of macular degeneration (134,135).
human ESC-derived cardiac progenitor cells in pa-
Similarly, iPSCs generated from patients with retinitis
tients with heart failure (150). On the basis of the pre-
pigmentosa, a condition that involves retinal degen-
clinical data showing a significant improvement in
eration, were able to differentiate to rod photore-
cardiac function caused by the paracrine effects of the
ceptor cells and have beneficial effects (136,137).
transplanted cardiac progenitor
Despite the excitement and momentum for the use of
ongoing clinical trial is using fibrin patches that
iPSC derivatives in clinical trials, a cautious approach
contain Isl-1þ SSEA-1 þ cells. The first clinical case
is advisable, because one of the clinical trials focused
report from this trial has found improvement in the
cells (151), this
on treating macular degeneration with iPSC-RPE cells
patient’s functional outcomes and evidence of new-
was recently halted because of genetic mutations in
onset contractility of the transplanted area (152);
the derived autologous cells. In addition, pre-clinical
however, the evaluation of efficacy remains specula-
data related to iPSCs have shown great promise for
tive, because these ESC-fibrin patches were implan-
various other ailments, including hematopoietic dis-
ted at the time of a coronary artery bypass graft
orders, spinal cord and musculoskeletal injury, and
procedure. Accordingly, more patients need to be
liver damage (138–141). Because a comprehensive
recruited, and randomized trials need to be per-
detailing of all these is beyond the scope of this re-
formed in the future.
view, we discuss only a few applications to cardiac
Tissue engineering: to the rescue of cell therapy. It has
diseases in the following sections.
become quite clear in the past few years that without
P a t c h i n g t h e b r o k e n h e a r t . Cardiovascular dis-
optimal bioengineering tools, the use of PSC-CMs for
eases remain the leading cause of mortality and
regenerative medicine might be limited. This is
morbidity in humans. PSC-derived cardiac tissue
evident given that previous studies using PSC-CMs or
might help restore diseased areas of the heart.
progenitor cells have seen only moderate success
Indeed, early work showed that PSC-CMs not only
because of the failure of cells either to survive
formed myocardial grafts but also electrically coupled
transplantation or to fully engraft into the host
and partially remuscularized the infarcted areas and
myocardium, which limits possible gains in cardiac
improved myocardial performance in small animal
function
models (142–145). Similarly, PSC-CMs have shown
engrafted cardiac cells with the host myocardium
promise in some pre-clinical large animal models
increases the risk of ventricular arrhythmias caused
(146). In a recent study, Chong et al. (147) reported
by electrical heterogeneity (147,148,154). A patch-
remuscularization of the infarcted region when hu-
based approach for cardiac repair might be more ad-
man ESC-CMs were injected into nonhuman primate
vantageous than intramyocardial injections, because
models of myocardial infarction. These grafts showed
the patch could simultaneously act as a substrate to
synchrony with the host myocardium, with regular
strengthen the injured myocardium and prevent
calcium transients and electrical coupling after
adverse remodeling, as well as provide a template for
transplantation; however, ventricular arrhythmias
cells to survive and even proliferate. With advances
were noted in these animals after transplantation,
in tissue bioengineering, diverse biomaterials have
and the study failed to show an improvement in their
been found with the potential to enhance cardiac cell
cardiac function. Clearly, significant hurdles still
therapy (155). These biomaterials (including collagen,
need to be overcome to translate this pre-clinical
fibrin, alginates, silk, decellularized heart matrix, and
report to a clinical trial. A much larger cohort of
synthetic polymers) now allow researchers to deliver
(153).
Similarly,
misalignment
of
the
2167
2168
Sayed et al.
JACC VOL. 67, NO. 18, 2016
MAY 10, 2016:2161–76
Human iPSCs for Precision Medicine
cells, retain them in situ, and use them to replace scar
rofecoxib (Vioxx, Merck & Co., Kenilworth, New Jer-
tissue with a large number of stem cell derivatives. In
sey), the gastrointestinal prokinetic drug cisapride
addition to being a vehicle for cell delivery, cardiac
(Propulsid; Johnson & Johnson, New Brunswick, New
patches have been shown to stimulate endogenous
Jersey), and the broad-spectrum antibacterial drug
paracrine factors that assist in cardiac repair (156,157).
grepafloxacin (Raxar, GlaxoSmithKline, Brentford,
Although there is much enthusiasm for the use of
United Kingdom), all of which were withdrawn
engineered heart tissue constructed from PSC-CMs
because of clinical cardiac or arrhythmogenic toxic-
for cardiac repair, there are some limitations that
ities (161). With the pharmaceutical industry invest-
need to be addressed, including how to engineer tis-
ing w$2 billion per new drug over a period of 10 to 15
sues that are simultaneously large enough to provide
years (162), this situation creates a tremendous
benefits but small enough to prevent death of the
burden on the health-care system. The drug with-
transplanted cells because of lack of oxygen and nu-
drawals are attributable in part to drug safety studies
trients. Even transplanted engineered heart muscle
being evaluated in less than ideal nonhuman animal
constructs showed poor survivability because of lack
cells and models after years of laboratory and pre-
of vascularization (158). Hence pre-vascularization of
clinical testing (Figure 2). The pharmaceutical in-
the in vitro heart tissue could potentially make these
dustry typically conducts its cardiotoxicity studies of
engineered patches more closely resemble the native
new drugs using in vitro cell lines, such as Chinese
human myocardium and allow survival of thicker
hamster ovary (CHO) cells and human embryonic
tissues. Indeed, the addition of human ECs to ESC-
kidney 293 (HEK293) cells overexpressing the I Kr
CMs enhanced formation of vessel-like structures
protein hERG (human ether-à-go-go-related gene)
and CM proliferation in vitro (110). Similarly, the
(163,164). However, these in vitro cell lines do not
addition of a vascular patch composed of human ESC-
replicate human CMs well, and the overexpression of
ECs and ESC-derived smooth muscle cells to a porcine
a single cardiac ion channel in these cells does not
model of myocardial infarction resulted in significant
recapitulate the complex channel biology in CMs.
improvements in
(159). Taken
Because of these limitations, there is an inherent risk
together, the continuing progress made in tissue en-
of cardiotoxic drugs slipping through initial screens
gineering to promote cell engraftment and survival
only to be withdrawn from the market after patients
after transplantation is expected to take us yet
have experienced harm and large investments have
another step closer to the clinical use of PSC-CMs in
been incurred or wasted. Moreover, the converse
regenerative medicine.
might also be true. It is possible that pre-clinical
cardiac
function
DRUG DISCOVERY AND TOXICITY SCREENING. In
the past, immortalized cell lines or experimental animal models have been used to screen therapeutic
agents for human diseases with limited success
because of differences from the actual human setting.
For example, it has always been difficult to analyze
and compare data between mice and humans for
cardiac diseases given the considerable variation in
their heart rates (e.g., mice exhibit a higher heart rate
of 500 to 600 beats/min compared with human heart
rates of 60 to 80 beats/min) and electrophysiological
properties (e.g., mice have shorter action potentials
than humans because of differences in cardiac ion
channels) (160). Studies using a patient’s primary
heart tissue are helpful but are limited because of lack
of donor availability, which makes in vitro modeling
using this approach difficult and hampers its use in
the evaluation of drug efficacy and toxicity.
testing of certain drugs using in vitro cell lines
might show toxicity, only for the same drug to be
later shown to be safe and efficacious for human usage (e.g., verapamil) (84,161). This could lead to
valuable drugs not being marketed or developed at all
because of inaccurate forecasting of their likely toxic
effects by use of conventional approaches.
With all these known roadblocks in conventional
drug screening, there is a compelling need to use
functional human CMs for drug screening. PSC-CMs
have now been comprehensively characterized as a
good model for cardiotoxicity studies. Using a standard protocol, electrophysiological responses of PSCCMs to a selection of known drugs that affect the
hERG channel have shown comparable data to conventional hERG by use of in vitro assays (165,166).
These studies indicate that PSC-CMs could be adopted as a standard model for cardiotoxicity studies.
Importantly
for
pharmaceutical
companies,
this
Conventional drug screening: a long, arduous
model could be a suitable addition to their conven-
r o a d . There has been a long list of high-profile drugs
tional drug screening methods.
that have been withdrawn from the market because of
iPSC-based drug screening: precise and personal. Every
their off-target and on-target toxicity to the heart,
patient has a unique genetic background and reacts
including the nonsteroidal anti-inflammatory drug
differently to medications. Despite presenting with
Sayed et al.
JACC VOL. 67, NO. 18, 2016
MAY 10, 2016:2161–76
2169
Human iPSCs for Precision Medicine
F I G U R E 2 Conventional Versus iPSC-Based Drug Discovery
(A) The conventional drug discovery pathway is a very inefficient process with a high attrition rate. The majority of candidate drugs never reach the market because of
safety and efficacy issues. This is attributable in part to the lack of appropriate drug development models that could accurately predict drug efficacy and in part to
dependence on animal models of disease that do not replicate human pathophysiology. (B) By comparison, induced pluripotent stem cell (iPSC) technology allows highthroughput screening of therapeutic molecules by providing disease-specific drug development models that are generated from the patients themselves. This makes iPSC
technology a much better predictive tool and enables well informed decisions to be made earlier in the drug development process. FDA ¼ U.S. Food and Drug
Administration; iPSC-CM ¼ induced pluripotent stem cell–derived cardiomyocyte.
similar symptoms, patients might have different un-
In addition, PSC-CMs could be cultured in a dish for
derlying causes of the disease, but conventionally,
extended periods of time (167), and large-scale pro-
they will still receive the same medication on the
duction of PSC-CMs is feasible from healthy control
basis of their symptoms. iPSC-based drug screening
subjects or patients with various cardiac diseases
technology might allow evaluation of a personalized
(Table 1). This iPSC-based model could provide a
therapy for every patient, an approach known as
valuable tool for the pre-clinical screening of candi-
precision medicine (30).
dates for whom a treatment would have therapeutic
With the advent of iPSCs (9) and the improvements
value and for screening candidates who might have
in differentiating iPSCs to functional CMs (27,29,90),
off-target cardiac toxicity in any individual genotype,
it is now feasible to generate functional human CMs
taking us one step closer to the goal of bringing pre-
for drug screening, thereby avoiding the issues asso-
cision medicine to the clinic (Figure 2).
ciated with earlier, less relevant screening systems
Although PSC-CMs provide an excellent platform
and minimizing the time and cost for drug develop-
for drug screening and toxicology studies (165), they
ment. These ESC-CMs and iPSC-CMs have been
currently have several limitations. For example, PSC-
thoroughly characterized to show similar electro-
CMs are generally immature and resemble fetal CMs
physiological,
biochemical,
and
pharmacological
both structurally and electrophysiologically (92,93).
functions that certify them as bona fide CMs (101).
This cellular immaturity issue might seriously limit
2170
Sayed et al.
JACC VOL. 67, NO. 18, 2016
MAY 10, 2016:2161–76
Human iPSCs for Precision Medicine
drug development with PSCs. To overcome this limi-
correctly identify a subset of patients with specific
tation, several approaches have been developed to
diseases who will respond to the drugs under study.
mature PSC-CMs, including differentiating them on
Similarly, depending on the effectiveness of the drug
3-dimensional patches, which could enhance their
in clinical trials, we might also gain the ability to
contractile apparatus (120,168). Others have tried to
diagnose sporadic diseases among a subset of pa-
achieve
microRNAs
tients. Given that iPSC-based clinical trials are in their
(miR-1/miR-499, Let7) to improve metabolic ener-
infancy, much work is still needed to rapidly and
getics (121,125) or by subjecting the cells to electrical
economically develop personalized iPSCs.
and mechanical stimulation (169). In addition, uni-
PRECISION MEDICINE: THE RIGHT DRUG FOR THE
axial stretching of engineered heart muscle made
RIGHT PATIENT AT THE RIGHT DOSE. The practice of
from PSC-CMs could enhance their viability and
medicine is undergoing a fundamental change.
maturation and has been used for drug screening
Rather than a generalized approach, the diagnostic
(170). Despite their resemblance to fetal CMs and their
and therapeutic strategies are now patient oriented,
maturity
by
overexpressing
labeling as “immature” CMs, these PSC-CMs have
with a focus on precision medicine (30). This involves
been used successfully to study drug efficacy and
integrating the patient’s “omics” information (e.g.,
toxicity (84,85).
genomic, epigenomic, transcriptomic, and metab-
iPSC CLINICAL TRIALS: TOWARD MACROMEDICINE. As
olomic) with advances in medical technology to tailor
described previously, iPSC technology has revolu-
therapeutic options for each individual patient. With
tionized the concept of precision medicine. In the
the advent of iPSC technology, this endeavor of pre-
past, because of the lack of available human samples,
cision medicine is now feasible.
drug toxicity screening was difficult and relied
There is an overwhelming consensus that cardiol-
heavily on immortalized cell-based assay or in vivo
ogy will lead the development of precision medicine,
animal models. Advances in iPSC technology could
after decades of research have revealed many of the
provide a steady supply of functional cells for
molecular pathways that cause cardiomyopathies.
pre-clinical screening of drugs. Moreover, iPSCs pro-
Moreover, the use of iPSC-derived cardiovascular
vide a unique platform that enables researchers to
cells has now enabled researchers to understand the
model diseases on a patient-by-patient basis. This
underlying mechanisms of many cardiac diseases that
micromedicine approach makes it possible to under-
were difficult to model because of lack of patient
stand disease progression at an individual patient
samples. This new understanding has started to in-
level and thus to screen for optimal pharmacological
fluence diagnostic and therapeutic strategies for car-
drugs individually. Beyond analyses performed for
diac diseases by the use of drugs that target specific
individual patients, high-throughput assays for drug
molecular drivers. For example, the phenotype of
toxicity that use human iPSC-CMs (171) can also be
iPSC-CMs derived from patients with long-QT syn-
conducted, supporting the role that iPSC technology
drome was found to be affected by b-adrenergic re-
can play in macromedicine, under which iPSC-based
ceptor blockers (53). Similarly, a drug for malignant
medicine could be applied to cohorts of patients
hyperthermia, dantrolene, was found to restore the
(172). In these clinical trials, iPSCs generated from
abnormal Ca2þ sparks and arrhythmogenic phenotype
patients could be differentiated into functional cells
of iPSC-CMs derived from patients with catechol-
and then used to analyze the efficacy of drugs (Central
aminergic polymorphic ventricular tachycardia (81).
Illustration). On this basis, patients could be classified
Such genotype-guided therapy is precise and, if
as drug responders or nonresponders, and only those
applied on a large scale, can transform patient care.
patients responding to the specific drugs would be
To achieve a deeper understanding of complex
moved to the next phase of the clinical trial. Thus,
genetic cardiomyopathies, many more cardiac ge-
iPSCs could provide valuable patient stratification
nomes need to be analyzed. This will require ad-
based on each patient’s responsiveness to the drug in
vances in medical technology that can help us better
clinical trials. Moreover, iPSCs could help us identify
understand heart disease and that are capable of
specific markers in the drug responders that corre-
predicting an optimal treatment plan for each patient.
spond to important patient subpopulations, thereby
With the availability of next-generation sequencing
boosting the success rate in clinical trials by
and
pre-selecting
Taken
pharmacogenomics can provide such valuable infor-
patients
who
will
benefit.
bioinformatics,
patient-specific
iPSC-based
together, iPSC technology has the potential to signifi-
mation. A patient’s iPSC-CMs could help identify the
cantly contribute to or even revolutionize macro-
genetic basis of the disease, followed by disease
medicine, for the first time allowing us to quickly and
modeling, finally leading to the identification of
JACC VOL. 67, NO. 18, 2016
MAY 10, 2016:2161–76
Sayed et al.
Human iPSCs for Precision Medicine
CENTRAL ILLUSTRATION iPSC Clinical Trial: From Micromedicine to Macromedicine
Sayed, N. et al. J Am Coll Cardiol. 2016;67(18):2161–76.
Induced pluripotent stem cell (iPSC) technology has contributed to both micromedicine and macromedicine. This includes everything from disease modeling and drug
development based on cellular and molecular analyses of individual patients to iPSC clinical trials for stratification based on cellular and molecular analyses of a cohort
of patients. Importantly, it could allow for the creation of a more precise clinical trial by identifying a subset of patients with a specific disease who optimally
respond to the drugs under investigation, thereby boosting success rates by pre-selecting these drug responders. DNA ¼ deoxyribonucleic acid; iPSC-CM ¼ induced
pluripotent stem cell–derived cardiomyocyte; RNA ¼ ribonucleic acid.
2171
2172
Sayed et al.
JACC VOL. 67, NO. 18, 2016
MAY 10, 2016:2161–76
Human iPSCs for Precision Medicine
pharmacogenetic
effective
drug
biomarkers
therapy.
This
that
can
facilitate
information,
once
platform to conduct drug-screening assays and to
discover
novel
therapeutics.
However,
a
major
collected, can be matched with drug discovery
concern thus far is the immature status of the PSC-
screens to predict the most effective drug treatment
CMs. Various approaches, including cardiac tissue
(combination) for each person. In conclusion, patient-
bioengineering, have been utilized to bring these
specific
iPSC-based
PSC-CMs to maturity. Finally, the availability of
pharmacogenomics have the potential to identify
genetically affected human tissues is very limited.
patient-specific genetic loci that are responsible for
Genome-edited PSC lines have now made it possible
disease and help develop the optimal individualized
to recapitulate the human disease in a dish by use of
therapeutic strategy for each patient.
various gene-editing tools, such as endonucleases
iPSC
disease
modeling
and
CONCLUSIONS AND FUTURE PERSPECTIVES
Since the initial basic discovery by Takahashi et al.
(8,9) that a set of 4 transcription factors could
reprogram mouse and human somatic cells to pluripotency, the field of iPSCs, free from the ethical issues associated with ESCs, has successfully expanded
to different avenues of regenerative medicine. To
date, iPSCs have 3 major applications, in disease
modeling, drug discovery, and regenerative medicine
(zinc finger nucleases or transcription activator–like
effector nuclease) or palindromic repeats (clustered
regularly-interspaced
short
palindromic
repeat).
Libraries of disease-specific cells can now be generated by creating allele-specific patient iPSC lines with
which to conduct drug testing and toxicity studies. In
summary, iPSC technology is not only revolutionizing
science but will also fundamentally alter our healthcare system and the future of medicine by making it
proactive, predictive, preventive, and personalized.
(173). Human iPSC-CMs have been used extensively to
ACKNOWLEDGMENTS The
characterize and model human heart diseases (174).
knowledge Joseph Gold, Jon Stack, and Blake Wu for
There have been more than 700 publications in the
critical reading of the manuscript and Amy Thomas for
past few years that have expanded their use to addi-
preparing the illustrations. Because of space con-
tional human diseases (both monogenic and poly-
straints, the authors could not include all of the rele-
genic). These advances in cardiac disease modeling
vant citations on the subject matter, for which they
have been made possible because of tissue-specific
apologize.
authors
gratefully
ac-
differentiation protocols that allowed researchers to
derive healthy and disease-specific CMs (Table 1). In
REPRINT REQUESTS AND CORRESPONDENCE: Dr.
addition to disease modeling, several groups have
Joseph C. Wu, Stanford Cardiovascular Institute, Stanford
tried to inject PSC-CMs into small and large animal
University School of Medicine, 265 Campus Drive G1120B,
models of myocardial infarction, with varying levels
Stanford, California 94305-5454. E-mail: joewu@stanford.
of success. Concerted efforts are now under way to
edu. OR Dr. Nazish Sayed, Stanford Cardiovascular Insti-
further enhance the pre-clinical outcome of these
tute, Stanford University School of Medicine, 265 Campus
PSC-CMs when transplanted into animal models of
Drive G1120B, Stanford, California 94305-5454. E-mail:
cardiac diseases. PSC-CMs also provide a unique
[email protected].
REFERENCES
1. Till JE, McCulloch EA. A direct measurement of
the radiation sensitivity of normal mouse bone
marrow cells. Radiat Res 1961;14:213–22.
2. Gurdon JB. The developmental capacity of
nuclei taken from intestinal epithelium cells of
feeding tadpoles. J Embryol Exp Morphol 1962;10:
622–40.
3. Wilmut I, Schnieke AE, McWhir J, Kind AJ,
Campbell KH. Viable offspring derived from fetal
and adult mammalian cells [published correction
appears in Nature 1997;386:200]. Nature 1997;
385:810–3.
4. Evans MJ, Kaufman MH. Establishment in culture of pluripotential cells from mouse embryos.
blastocysts [published correction appears in Science 1998;282:1827]. Science 1998;282:1145–7.
6. Tada M, Takahama Y, Abe K, Nakatsuji N,
Tada T. Nuclear reprogramming of somatic cells by
in vitro hybridization with ES cells. Curr Biol 2001;
11:1553–8.
7. Davis RL, Weintraub H, Lassar AB. Expression of
a single transfected cDNA converts fibroblasts to
myoblasts. Cell 1987;51:987–1000.
8. Takahashi K, Yamanaka S. Induction of pluripotent stem cells from mouse embryonic and adult
fibroblast cultures by defined factors. Cell 2006;
126:663–76.
10. Marson A, Foreman R, Chevalier B, et al. Wnt
signaling promotes reprogramming of somatic
cells to pluripotency. Cell Stem Cell 2008;3:
132–5.
11. Huangfu D, Maehr R, Guo W, et al. Induction of
pluripotent stem cells by defined factors is greatly
improved by small-molecule compounds. Nat
Biotech 2008;26:795–7.
12. Dimos JT, Rodolfa KT, Niakan KK, et al.
Induced pluripotent stem cells generated from
patients with ALS can be differentiated into motor
neurons. Science 2008;321:1218–21.
Nature 1981;292:154–6.
9. Takahashi K, Tanabe K, Ohnuki M, et al. Induction of pluripotent stem cells from adult human
13. Hanna J, Markoulaki S, Schorderet P, et al.
Direct reprogramming of terminally differentiated
mature B lymphocytes to pluripotency [published
5. Thomson JA, Itskovitz-Eldor J, Shapiro SS, et al.
Embryonic stem cell lines derived from human
fibroblasts by defined factors. Cell 2007;131:
861–72.
correction appears in Cell 2008;134:365]. Cell
2008;133:250–64.
Sayed et al.
JACC VOL. 67, NO. 18, 2016
MAY 10, 2016:2161–76
14. Sun N, Panetta NJ, Gupta DM, et al. Feederfree derivation of induced pluripotent stem cells
from adult human adipose stem cells. Proc Natl
Acad Sci U S A 2009;106:15720–5.
15. Yu J, Vodyanik MA, Smuga-Otto K, et al.
Induced pluripotent stem cell lines derived from
human somatic cells. Science 2007;318:1917–20.
16. Zhao Y, Yin X, Qin H, et al. Two supporting
factors greatly improve the efficiency of human
iPSC generation. Cell Stem Cell 2008;3:475–9.
17. Woltjen K, Michael IP, Mohseni P, et al. piggyBac transposition reprograms fibroblasts to
induced pluripotent stem cells. Nature 2009;458:
766–70.
18. Carey BW, Markoulaki S, Hanna J, et al.
Reprogramming of murine and human somatic
cells using a single polycistronic vector [published
corrections appear in Proc Natl Acad Sci U S A
2009;106:5449 and Proc Natl Acad Sci U S A
2009;106:11818]. Proc Natl Acad Sci U S A 2009;
106:157–62.
19. Jia F, Wilson KD, Sun N, et al. A nonviral
minicircle vector for deriving human iPS cells. Nat
Methods 2010;7:197–9.
20. Wernig M, Lengner CJ, Hanna J, et al.
A drug-inducible transgenic system for direct
reprogramming of multiple somatic cell types. Nat
Biotechnol 2008;26:916–24.
21. Warren L, Manos PD, Ahfeldt T, et al. Highly
efficient reprogramming to pluripotency and
directed differentiation of human cells with synthetic modified mRNA. Cell Stem Cell 2010;7:
618–30.
22. Zhou H, Wu S, Joo JY, et al. Generation of
induced pluripotent stem cells using recombinant
proteins [published correction appears in Cell
Stem Cell 2009;4:581]. Cell Stem Cell 2009;4:
381–4.
23. Lee J, Sayed N, Hunter A, et al. Activation of
innate immunity is required for efficient nuclear
reprogramming. Cell 2012;151:547–58.
24. Hou P, Li Y, Zhang X, et al. Pluripotent stem
cells induced from mouse somatic cells by smallmolecule compounds. Science 2013;341:651–4.
25. Neofytou E, O’Brien CG, Couture LA, Wu JC.
Hurdles to clinical translation of human induced
pluripotent stem cells. J Clin Invest 2015;125:
2551–7.
26. Kimbrel EA, Lanza R. Current status of
pluripotent stem cells: moving the first therapies
to the clinic. Nat Rev Drug Discov 2015;14:681–92.
27. Burridge PW, Keller G, Gold JD, Wu JC. Production of de novo cardiomyocytes: human
pluripotent stem cell differentiation and direct
reprogramming. Cell Stem Cell 2012;10:16–28.
28. Matsa E, Burridge PW, Wu JC. Human stem
cells for modeling heart disease and for drug discovery. Sci Transl Med 2014;6:239ps6.
29. Burridge PW, Matsa E, Shukla P, et al. Chemically defined generation of human car-
Human iPSCs for Precision Medicine
31. Polo JM, Anderssen E, Walsh RM, et al.
A molecular roadmap of reprogramming somatic
cells into iPS cells. Cell 2012;151:1617–32.
32. Buganim Y, Faddah DA, Cheng AW, et al.
Single-cell expression analyses during cellular
reprogramming reveal an early stochastic and a
late hierarchic phase. Cell 2012;150:1209–22.
cardiomyocytes using Gata4, Mef2c, and Tbx5.
Circ Res 2012;111:50–5.
48. Ebert AD, Diecke S, Chen IY, Wu JC. Reprogramming and transdifferentiation for cardiovascular development and regenerative medicine:
where do we stand? EMBO Mol Med 2015;7:
1090–103.
33. Rais Y, Zviran A, Geula S, et al. Deterministic
direct reprogramming of somatic cells to pluripotency [published correction appears in Nature
2015;520:710]. Nature 2013;502:65–70.
49. Merkle FT, Eggan K. Modeling human disease
with pluripotent stem cells: from genome association to function. Cell Stem Cell 2013;12:656–68.
34. Chin MH, Mason MJ, Xie W, et al. Induced
pluripotent stem cells and embryonic stem cells
are distinguished by gene expression signatures.
Cell Stem Cell 2009;5:111–23.
877–86.
35. Ghosh Z, Wilson KD, Wu Y, Hu S,
Quertermous T, Wu JC. Persistent donor cell gene
expression among human induced pluripotent
stem cells contributes to differences with human
embryonic stem cells. PLoS One 2010;5:e8975.
36. Deng J, Shoemaker R, Xie B, et al. Targeted
bisulfite sequencing reveals changes in DNA
methylation associated with nuclear reprogramming. Nat Biotechnol 2009;27:353–60.
37. Bock C, Kiskinis E, Verstappen G, et al. Reference maps of human ES and iPS cell variation
enable high-throughput characterization of
pluripotent cell lines. Cell 2011;144:439–52.
38. Guenther MG, Frampton GM, Soldner F, et al.
Chromatin structure and gene expression programs of human embryonic and induced pluripotent stem cells. Cell Stem Cell 2010;7:249–57.
39. Newman AM, Cooper JB. Lab-specific gene
expression signatures in pluripotent stem cells.
Cell Stem Cell 2010;7:258–62.
50. Park IH, Arora N, Huo H, et al. Disease-specific
induced pluripotent stem cells. Cell 2008;134:
51. Carvajal-Vergara X, Sevilla A, D’Souza SL, et al.
Patient-specific induced pluripotent stem-cellderived models of LEOPARD syndrome. Nature
2010;465:808–12.
52. Marchetto MCN, Winner B, Gage FH. Pluripotent stem cells in neurodegenerative and neurodevelopmental diseases. Hum Mol Genet 2010;19:
R71–6.
53. Moretti A, Bellin M, Welling A, et al. Patientspecific induced pluripotent stem-cell models for
long-QT syndrome. N Engl J Med 2010;363:
1397–409.
54. Itzhaki I, Maizels L, Huber I, et al. Modelling
the long QT syndrome with induced pluripotent
stem cells. Nature 2011;471:225–9.
55. Matsa E, Rajamohan D, Dick E, et al. Drug
evaluation in cardiomyocytes derived from human
induced pluripotent stem cells carrying a long QT
syndrome type 2 mutation. Eur Heart J 2011;32:
952–62.
40. Choi J, Lee S, Mallard W, et al. A comparison
of genetically matched cell lines reveals the
equivalence of human iPSCs and ESCs. Nat Biotech
56. Narsinh K, Narsinh KH, Wu JC. Derivation of
human induced pluripotent stem cells for cardiovascular disease modeling. Circ Res 2011;108:
1146–56.
2015;33:1173–81.
57. Filareto A, Parker S, Darabi R, et al. An ex vivo
41. Sayed N, Wong WT, Cooke JP. Therapeutic
gene therapy approach to treat muscular dystrophy using inducible pluripotent stem cells. Nat
Commun 2013;4:1549.
transdifferentiation: can we generate cardiac tissue rather than scar after myocardial injury?
Methodist Debakey Cardiovasc J 2013;9:210–2.
42. Vierbuchen T, Ostermeier A, Pang ZP,
Kokubu Y, Südhof TC, Wernig M. Direct conversion
of fibroblasts to functional neurons by defined
factors. Nature 2010;463:1035–41.
43. Huang P, He Z, Ji S, et al. Induction of functional hepatocyte-like cells from mouse fibroblasts by defined factors. Nature 2011;475:386–9.
44. Ieda M, Fu JD, Delgado-Olguin P, et al. Direct
58. Lin B, Li Y, Han L, et al. Modeling and study of
the mechanism of dilated cardiomyopathy using
induced pluripotent stem cells derived from individuals with Duchenne muscular dystrophy. Dis
Model Mech 2015;8:457–66.
59. Raya Á, Rodríguez-Pizà I, Guenechea G, et al.
Disease-corrected haematopoietic progenitors
from Fanconi anaemia induced pluripotent stem
cells. Nature 2009;460:53–9.
reprogramming of fibroblasts into functional cardiomyocytes by defined factors. Cell 2010;142:
375–86.
60. Urbach A, Bar-Nur O, Daley GQ, Benvenisty N.
Differential modeling of fragile X syndrome by
45. Margariti A, Winkler B, Karamariti E, et al.
Direct reprogramming of fibroblasts into endothelial cells capable of angiogenesis and reendothelialization in tissue-engineered vessels. Proc
Natl Acad Sci U S A 2012;109:13793–8.
61. Novak A, Barad L, Lorber A, et al. Functional
abnormalities in iPSC-derived cardiomyocytes
generated from CPVT1 and CPVT2 patients car-
46. Sayed N, Wong WT, Ospino F, et al. Transdifferentiation of human fibroblasts to endothelial
diomyocytes. Nat Methods 2014;11:855–60.
cells: role of innate immunity. Circulation 2015;
131:300–9.
30. Collins FS, Varmus H. A new initiative on
precision medicine. N Engl J Med 2015;372:793–5.
47. Chen JX, Krane M, Deutsch MA, et al. Inefficient reprogramming of fibroblasts into
human embryonic stem cells and induced pluripotent stem cells. Cell Stem Cell 2010;6:407–11.
rying ryanodine or calsequestrin mutations. J Cell
Mol Med 2015;19:2006–18.
62. Lan F, Lee AS, Liang P, et al. Abnormal calcium
handling properties underlie familial hypertrophic
cardiomyopathy pathology in patient-specific
induced pluripotent stem cells. Cell Stem Cell
2013;12:101–13.
2173
2174
Sayed et al.
JACC VOL. 67, NO. 18, 2016
MAY 10, 2016:2161–76
Human iPSCs for Precision Medicine
63. Siu CW, Lee YK, Ho JC, et al. Modeling of lamin
A/C mutation premature cardiac aging using
patient-specific induced pluripotent stem cells.
Aging (Albany NY) 2012;4:803–22.
of human pluripotent stem cells. Curr Protoc Hum
Genet 2015;87:21.3.1–21.3.15.
induced pluripotent stem cells. Circ Res 2009;
104:e30–41.
78. Mordwinkin NM, Lee AS, Wu JC. Patientspecific stem cells and cardiovascular drug
92. Yang X, Pabon L, Murry CE. Engineering
adolescence: maturation of human pluripotent
64. Sun N, Yazawa M, Liu J, et al. Patient-specific
induced pluripotent stem cells as a model for fa-
discovery. JAMA 2013;310:2039–40.
stem cell–derived cardiomyocytes. Circ Res 2014;
114:511–23.
milial dilated cardiomyopathy. Sci Transl Med
2012;4:130ra47.
65. Wu H, Lee J, Vincent LG, et al. Epigenetic
regulation of phosphodiesterases 2A and 3A
underlies compromised b-adrenergic signaling in
an iPSC model of dilated cardiomyopathy. Cell
Stem Cell 2015;17:89–100.
66. Hinson JT, Chopra A, Nafissi N, et al. Titin
mutations in iPS cells define sarcomere insufficiency as a cause of dilated cardiomyopathy. Science 2015;349:982–6.
67. Tse HF, Ho JC, Choi SW, et al. Patient-specific
induced-pluripotent stem cells-derived cardiomyocytes recapitulate the pathogenic phenotypes of dilated cardiomyopathy due to a novel
DES mutation identified by whole exome
sequencing [published correction appears in Hum
Mol Genet 2014;23:2332–3]. Hum Mol Genet 2013;
22:1395–403.
68. Karakikes I, Stillitano F, Nonnenmacher M,
et al. Correction of human phospholamban R14del
mutation associated with cardiomyopathy using
targeted nucleases and combination therapy. Nat
Commun 2015;6:6955.
79. Egashira T, Yuasa S, Suzuki T, et al. Disease
characterization using LQTS-specific induced
pluripotent stem cells. Cardiovasc Res 2012;95:
419–29.
80. Lahti AL, Kujala VJ, Chapman H, et al. Model
for long QT syndrome type 2 using human iPS cells
demonstrates arrhythmogenic characteristics in
cell culture. Dis Model Mech 2012;5:220–30.
81. Jung CB, Moretti A, Mederos y Schnitzler M,
et al. Dantrolene rescues arrhythmogenic RYR2
defect in a patient-specific stem cell model of
catecholaminergic polymorphic ventricular tachycardia. EMBO Mol Med 2012;4:180–91.
82. Novak A, Barad L, Zeevi-Levin N, et al. Cardiomyocytes generated from CPVTD307H patients
are arrhythmogenic in response to b-adrenergic
stimulation. J Cell Mol Med 2012;16:468–82.
83. Asimaki A, Kapoor S, Plovie E, et al. Identification of a new modulator of the intercalated disc
in a zebrafish model of arrhythmogenic cardiomyopathy [published correction appears in Sci
Transl Med 2014;6:261er6]. Sci Transl Med 2014;
6:240ra74.
PSC-cardiomyocyte function. Cell Rep 2015;13:
733–45.
84. Navarrete EG, Liang P, Lan F, et al. Screening
drug-induced arrhythmia using human induced
pluripotent stem cell–derived cardiomyocytes and
low-impedance microelectrode arrays [published
correction appears in Circulation 2014;129:e452].
Circulation 2013;128:S3–13.
70. Wang G, McCain ML, Yang L, et al. Modeling
the mitochondrial cardiomyopathy of Barth syndrome with induced pluripotent stem cell and
heart-on-chip technologies. Nat Med 2014;20:
616–23.
85. Liang P, Lan F, Lee AS, et al. Drug screening
using a library of human induced pluripotent stem
cell–derived cardiomyocytes reveals diseasespecific patterns of cardiotoxicity. Circulation
2013;127:1677–91.
71. Wang Y, Liang P, Lan F, et al. Genome editing
of isogenic human induced pluripotent stem cells
recapitulates long QT phenotype for drug testing.
86. Drawnel FM, Boccardo S, Prummer M, et al.
69. Birket MJ, Ribeiro MC, Kosmidis G, et al.
Contractile defect caused by mutation in MYBPC3
revealed under conditions optimized for human
J Am Coll Cardiol 2014;64:451–9.
72. Ma D, Wei H, Zhao Y, et al. Modeling type 3
long QT syndrome with cardiomyocytes derived
from patient-specific induced pluripotent stem
cells. Int J Cardiol 2013;168:5277–86.
73. Yazawa M, Hsueh B, Jia X, et al. Using induced
pluripotent stem cells to investigate cardiac phenotypes in Timothy syndrome. Nature 2011;471:
230–4.
74. Kim C, Wong J, Wen J, et al. Studying
arrhythmogenic right ventricular dysplasia with
patient-specific iPSCs. Nature 2013;494:105–10.
75. Sato Y, Kobayashi H, Higuchi T, et al. Disease
modeling and lentiviral gene transfer in patientspecific induced pluripotent stem cells from lateonset Pompe disease patient. Mol Ther Methods
Clin Dev 2015;2:15023.
Disease modeling and phenotypic drug screening
for diabetic cardiomyopathy using human induced
pluripotent stem cells. Cell Rep 2014;9:810–21.
87. Sharma A, Marceau C, Hamaguchi R, et al.
Human induced pluripotent stem cell-derived
cardiomyocytes as an in vitro model for coxsackievirus B3-induced myocarditis and antiviral drug
screening platform. Circ Res 2014;115:556–66.
88. Aggarwal P, Turner A, Matter A, et al. RNA
expression profiling of human iPSC-derived cardiomyocytes in a cardiac hypertrophy model. PLoS
One 2014;9:e108051.
89. Ebert AD, Kodo K, Liang P, et al. Characterization of the molecular mechanisms underlying
increased ischemic damage in the aldehyde dehydrogenase 2 genetic polymorphism using a human
induced pluripotent stem cell model system. Sci
Transl Med 2014;6:255ra130.
90. Lian X, Zhang J, Azarin SM, et al. Directed
76. Lee YK, Ho PW, Schick R, et al. Modeling of
Friedreich ataxia-related iron overloading cardiomyopathy using patient-specific-induced pluripotent stem cells. Pflugers Arch 2014;466:1831–44.
cardiomyocyte differentiation from human
pluripotent stem cells by modulating Wnt/bcatenin signaling under fully defined conditions.
Nat Protoc 2013;8:162–75.
77. Burridge PW, Holmström A, Wu JC. Chemically
defined culture and cardiomyocyte differentiation
91. Zhang J, Wilson GF, Soerens AG, et al. Functional cardiomyocytes derived from human
93. Karakikes I, Ameen M, Termglinchan V, Wu JC.
Human induced pluripotent stem cell-derived
cardiomyocytes: insights into molecular, cellular,
and functional phenotypes. Circ Res 2015;117:
80–8.
94. Snir M, Kehat I, Gepstein A, et al. Assessment
of the ultrastructural and proliferative properties
of human embryonic stem cell-derived cardiomyocytes. Am J Physiol Heart Circ Physiol
2003;285:H2355–63.
95. Veerman CC, Kosmidis G, Mummery CL,
Casini S, Verkerk AO, Bellin M. Immaturity of human stem-cell-derived cardiomyocytes in culture:
fatal flaw or soluble problem? Stem Cells Dev
2015;24:1035–52.
96. Mollova M, Bersell K, Walsh S, et al. Cardiomyocyte proliferation contributes to heart
growth in young humans. Proc Natl Acad Sci U S A
2013;110:1446–51.
97. Lundy SD, Zhu WZ, Regnier M, Laflamme MA.
Structural and functional maturation of cardiomyocytes derived from human pluripotent
stem cells. Stem Cells Dev 2013;22:1991–2002.
98. Ivashchenko CY, Pipes GC, Lozinskaya IM,
et al. Human-induced pluripotent stem cellderived cardiomyocytes exhibit temporal changes
in phenotype. Am J Physiol Heart Circ Physiol
2013;305:H913–22.
99. LeWinter MM, Granzier HL. Cardiac titin and
heart disease. J Cardiovasc Pharmacol 2014;63:
207–12.
100. Bedada FB, Chan SSK, Metzger SK, et al.
Acquisition of a quantitative, stoichiometrically
conserved ratiometric marker of maturation status
in stem cell-derived cardiac myocytes. Stem Cell
Reports 2014;3:594–605.
101. Ma J, Guo L, Fiene SJ, et al. High purity
human-induced pluripotent stem cell-derived
cardiomyocytes: electrophysiological properties
of action potentials and ionic currents. Am J
Physiol Heart Circ Physiol 2011;301:H2006–17.
102. Davis RP, Casini S, van den Berg CW, et al.
Cardiomyocytes derived from pluripotent stem
cells recapitulate electrophysiological characteristics of an overlap syndrome of cardiac sodium
channel disease. Circulation 2012;125:3079–91.
103. Cordeiro JM, Nesterenko VV, Sicouri S, et al.
Identification and characterization of a transient
outward Kþ current in human induced pluripotent
stem cell-derived cardiomyocytes. J Mol Cell
Cardiol 2013;60:36–46.
104. Devalla HD, Schwach V, Ford JW, et al.
Atrial-like cardiomyocytes from human pluripotent stem cells are a robust preclinical model for
assessing atrial-selective pharmacology. EMBO
Mol Med 2015;7:394–410.
105. Lee P, Klos M, Bollensdorff C, et al. Simultaneous voltage and calcium mapping of genetically purified human induced pluripotent stem
Sayed et al.
JACC VOL. 67, NO. 18, 2016
MAY 10, 2016:2161–76
cell–derived cardiac myocyte monolayers. Circ Res
2012;110:1556–63.
106. Vreeker A, van Stuijvenberg L, Hund TJ,
Mohler PJ, Nikkels PG, van Veen TA. Assembly of
the cardiac intercalated disk during pre- and
postnatal development of the human heart. PLoS
One 2014;9:e94722.
107. Itzhaki I, Rapoport S, Huber I, et al. Calcium
handling in human induced pluripotent stem cell
derived cardiomyocytes. PLoS One 2011;6:e18037.
108. Binah O, Dolnikov K, Sadan O, et al. Functional and developmental properties of human
embryonic stem cells-derived cardiomyocytes.
J Electrocardiol 2007;40 Suppl:S192–6.
109. Liu J, Fu JD, Siu CW, Li RA. Functional
sarcoplasmic reticulum for calcium handling of
human embryonic stem cell-derived cardiomyocytes: insights for driven maturation. Stem
Cells 2007;25:3038–44.
110. Tulloch NL, Muskheli V, Razumova MV, et al.
Growth of engineered human myocardium with
mechanical loading and vascular coculture. Circ
Res 2011;109:47–59.
111. Synnergren J, Améen C, Jansson A, Sartipy P.
Global transcriptional profiling reveals similarities
and differences between human stem cell-derived
cardiomyocyte clusters and heart tissue. Physiol
Genomics 2012;44:245–58.
112. Wiegerinck RF, Cojoc A, Zeidenweber CM,
et al. Force frequency relationship of the human
ventricle increases during early postnatal development. Pediatr Res 2009;65:414–9.
113. Keung W, Boheler KR, Li RA. Developmental
cues for the maturation of metabolic, electrophysiological and calcium handling properties of
human pluripotent stem cell-derived cardiomyocytes. Stem Cell Res Ther 2014;5:17.
114. St John JC, Ramalho-Santos J, Gray HL, et al.
The expression of mitochondrial DNA transcription
factors during early cardiomyocyte in vitro differentiation from human embryonic stem cells.
Cloning Stem Cells 2005;7:141–53.
115. Chung S, Dzeja PP, Faustino RS, PerezTerzic C, Behfar A, Terzic A. Mitochondrial
oxidative metabolism is required for the cardiac
differentiation of stem cells. Nat Clin Pract Cardiovasc Med 2007;4 Suppl 1:S60–7.
116. Lopaschuk GD, Collins-Nakai RL, Itoi T.
Developmental changes in energy substrate use
by the heart. Cardiovasc Res 1992;26:1172–80.
117. Pillekamp F, Haustein M, Khalil M, et al.
Contractile properties of early human embryonic
stem
cell-derived
cardiomyocytes:
betaadrenergic stimulation induces positive chronotropy and lusitropy but not inotropy. Stem Cells
Dev 2012;21:2111–21.
118. Földes G, Matsa E, Kriston-Vizi J, et al.
Aberrant a-adrenergic hypertrophic response in
cardiomyocytes from human induced pluripotent
cells. Stem Cell Reports 2014;3:905–14.
119. Jacot JG, McCulloch AD, Omens JH. Substrate
stiffness affects the functional maturation of
neonatal rat ventricular myocytes. Biophys J
2008;95:3479–87.
120. Tzatzalos E, Abilez OJ, Shukla P, Wu JC.
Engineered heart tissues and induced pluripotent
Human iPSCs for Precision Medicine
stem cells: macro- and microstructures for disease
modeling, drug screening, and translational
studies. Adv Drug Deliv Rev 2016;96:234–44.
121. Fu JD, Rushing SN, Lieu DK, et al. Distinct
roles of microRNA-1 and -499 in ventricular
specification and functional maturation of human
embryonic stem cell-derived cardiomyocytes.
PLoS One 2011;6:e27417.
122. Wilson KD, Hu S, Venkatasubrahmanyam S,
et al. Dynamic microRNA expression programs
during cardiac differentiation of human embryonic
stem cells: role for miR-499. Circ Cardiovasc
Genet 2010;3:426–35.
123. Zhang CL, McKinsey TA, Chang S, Antos CL,
Hill JA, Olson EN. Class II histone deacetylases act
as signal-responsive repressors of cardiac hypertrophy. Cell 2002;110:479–88.
124. Gilsbach R, Preissl S, Grüning BA, et al. Dynamic DNA methylation orchestrates cardiomyocyte development, maturation and disease.
Nat Commun 2014;5:5288.
125. Kuppusamy KT, Jones DC, Sperber H, et al.
Let-7 family of microRNA is required for maturation and adult-like metabolism in stem cellderived cardiomyocytes. Proc Natl Acad Sci U S A
2015;112:E2785–94.
126. Földes G, Mioulane M, Wright JS, et al.
Modulation of human embryonic stem cell-derived
cardiomyocyte growth: a testbed for studying
human cardiac hypertrophy? J Mol Cell Cardiol
2011;50:367–76.
127. Chattergoon NN, Giraud GD, Louey S, Stork P,
Fowden AL, Thornburg KL. Thyroid hormone
drives fetal cardiomyocyte maturation. FASEB J
2012;26:397–408.
128. Kim H, Kim JS. A guide to genome engineering with programmable nucleases. Nat Rev
Genet 2014;15:321–34.
129. Esvelt KM, Wang HH. Genome-scale engineering for systems and synthetic biology. Mol
Syst Biol 2013;9:641.
130. Bellin M, Casini S, Davis RP, et al. Isogenic
human pluripotent stem cell pairs reveal the role
of a KCNH2 mutation in long-QT syndrome. EMBO
J 2013;32:3161–75.
131. Long C, McAnally JR, Shelton JM,
Mireault AA, Bassel-Duby R, Olson EN. Prevention
of muscular dystrophy in mice by CRISPR/Cas9–
mediated editing of germline DNA. Science 2014;
345:1184–8.
132. Cox DBT, Platt RJ, Zhang F. Therapeutic
genome editing: prospects and challenges. Nat
Med 2015;21:121–31.
133. ClinicalTrials.gov. NCT01344993. NCT01345006.
NCT01469832.
NCT01625559.
NCT01674829.
NCT01691261.
NCT02122159.
NCT02286089.
NCT02464956. Available at: https://clinicaltrials.gov.
Accessed February 27, 2016.
134. Lu B, Malcuit C, Wang S, et al. Long-term
safety and function of RPE from human embryonic
stem cells in preclinical models of macular
degeneration. Stem Cells 2009;27:2126–35.
135. Kamao H, Mandai M, Okamoto S, et al.
Characterization of human induced pluripotent
stem cell-derived retinal pigment epithelium cell
sheets aiming for clinical application. Stem Cell
Reports 2014;2:205–18.
136. Yoshida T, Ozawa Y, Suzuki K, et al. The use
of induced pluripotent stem cells to reveal pathogenic gene mutations and explore treatments for
retinitis pigmentosa. Mol Brain 2014;7:45.
137. Li Y, Tsai YT, Hsu CW, et al. Long-term safety
and efficacy of human-induced pluripotent stem
cell (iPS) grafts in a preclinical model of retinitis
pigmentosa. Mol Med 2012;18:1312–9.
138. Liu H, Kim Y, Sharkis S, Marchionni L, Jang YY.
In vivo liver regeneration potential of human
induced pluripotent stem cells from diverse origins. Sci Transl Med 2011;3:82ra39.
139. Nori S, Okada Y, Yasuda A, et al. Grafted
human-induced pluripotent stem-cell–derived
neurospheres promote motor functional recovery
after spinal cord injury in mice. Proc Natl Acad Sci
U S A 2011;108:16825–30.
140. Tan Q, Lui PPY, Rui YF, Wong YM. Comparison of potentials of stem cells isolated from
tendon and bone marrow for musculoskeletal tissue engineering. Tissue Eng Part A 2011;18:
840–51.
141. Suzuki N, Yamazaki S, Yamaguchi T, et al.
Generation of engraftable hematopoietic stem
cells from induced pluripotent stem cells by way
of teratoma formation. Mol Ther 2013;21:1424–31.
142. Laflamme MA, Chen KY, Naumova AV, et al.
Cardiomyocytes derived from human embryonic
stem cells in pro-survival factors enhance function
of infarcted rat hearts. Nat Biotechnol 2007;25:
1015–24.
143. Caspi O, Huber I, Kehat I, et al. Transplantation of human embryonic stem cell-derived
cardiomyocytes improves myocardial performance in infarcted rat hearts. J Am Coll Cardiol
2007;50:1884–93.
144. Cao F, Wagner RA, Wilson KD, et al. Transcriptional and functional profiling of human embryonic stem cell-derived cardiomyocytes. PLoS
One 2008;3:e3474.
145. Shiba Y, Fernandes S, Zhu WZ, et al. Human
ES-cell-derived cardiomyocytes electrically couple
and suppress arrhythmias in injured hearts. Nature
2012;489:322–5.
146. Ye L, Chang YH, Xiong Q, et al. Cardiac repair
in a porcine model of acute myocardial infarction
with human induced pluripotent stem cell-derived
cardiovascular cells [published correction appears
in Cell Stem Cell 2015;16:102]. Cell Stem Cell
2014;15:750–61.
147. Chong JJH, Yang X, Don CW, et al. Human
embryonic-stem-cell-derived
cardiomyocytes
regenerate non-human primate hearts. Nature
2014;510:273–7.
148. Anderson ME, Goldhaber J, Houser SR,
Puceat M, Sussman MA. Embryonic stem cell–
derived cardiac myocytes are not ready for human
trials. Circ Res 2014;115:335–8.
149. Murry CE, Chong JJH, Laflamme MA. Letter
by Murry et al regarding article, “Embryonic stem
cell–derived cardiac myocytes are not ready for
human trials.” Circ Res 2014;115:e28–9.
150. Assistance
Transplantation
Publique-Hôpitaux de Paris.
of human embryonic stem
2175
2176
Sayed et al.
JACC VOL. 67, NO. 18, 2016
MAY 10, 2016:2161–76
Human iPSCs for Precision Medicine
cell-derived progenitors in severe heart failure
(ESCORT). ClinicalTrials.gov. Available at: https://
clinicaltrials.gov/ct2/show/NCT02057900. Accessed
February 27, 2016.
151. Bellamy V, Vanneaux V, Bel A, et al. Longterm functional benefits of human embryonic stem
cell-derived cardiac progenitors embedded into a
fibrin scaffold. J Heart Lung Transplant 2015;34:
1198–207.
152. Menasché P, Vanneaux V, Hagège A, et al.
Human embryonic stem cell-derived cardiac
progenitors for severe heart failure treatment:
first clinical case report. Eur Heart J 2015;36:
2011–7.
153. Riegler J, Gillich A, Shen Q, Gold JD, Wu JC.
Cardiac tissue slice transplantation as a model to
assess tissue-engineered graft thickness, survival, and function. Circulation 2014;130 11 Suppl
1:S77–86.
term in a rodent myocardial infarction model. Circ
Res 2015;117:720–30.
159. Xiong Q, Hill KL, Li Q, et al. A fibrin patchbased enhanced delivery of human embryonic
stem cell-derived vascular cell transplantation in a
porcine model of postinfarction left ventricular
remodeling. Stem Cells 2011;29:367–75.
160. Rajamohan D, Matsa E, Kalra S, et al. Current
status of drug screening and disease modelling in
human pluripotent stem cells. Bioessays 2013;35:
281–98.
161. Sallam K, Li Y, Sager PT, Houser SR, Wu JC.
Finding the rhythm of sudden cardiac death: new
opportunities using induced pluripotent stem cell–
derived cardiomyocytes. Circ Res 2015;116:
1989–2004.
167. He JQ, Ma Y, Lee Y, Thomson JA, Kamp TJ.
Human embryonic stem cells develop into multiple types of cardiac myocytes: action potential
characterization. Circ Res 2003;93:32–9.
168. Zhang D, Shadrin IY, Lam J, Xian HQ,
Snodgrass HR, Bursac N. Tissue-engineered cardiac patch for advanced functional maturation of
human ESC-derived cardiomyocytes. Biomaterials
2013;34:5813–20.
169. Burridge PW, Sharma A, Wu JC. Genetic and
epigenetic regulation of human cardiac reprogramming and differentiation in regenerative medicine. Annu Rev Genet 2015;49:461–84.
170. Mathur A, Loskill P, Shao K, et al. Human
iPSC-based cardiac microphysiological system for
drug screening applications. Sci Rep 2015;5:
8883.
162. Adams CP, Brantner VV. Spending on new
drug development. Health Econ 2010;19:130–41.
154. Pijnappels DA, Schalij MJ, Atsma DE, de
Vries AA. Cardiac anisotropy, regeneration, and
rhythm. Circ Res 2014;115:e6–7.
Channels (Austin) 2008;2:87–93.
171. Guo L, Abrams RMC, Babiarz JE, et al. Estimating the risk of drug-induced proarrhythmia
using human induced pluripotent stem cell–
derived cardiomyocytes. Toxicol Sci 2011;123:
281–9.
155. Ye L, Zimmermann WH, Garry DJ, Zhang J.
Patching the heart: cardiac repair from within and
outside. Circ Res 2013;113:922–32.
164. Thomas D, Karle CA, Kiehn J. The cardiac
hERG/IKr potassium channel as pharmacological
target: structure, function, regulation, and clin-
172. Inoue H, Nagata N, Kurokawa H, Yamanaka S.
iPS cells: a game changer for future medicine.
EMBO J 2014;33:409–17.
156. Xiong Q, Ye L, Zhang P, et al. Bioenergetic
and functional consequences of cellular therapy:
ical applications. Curr Pharm Des 2006;12:
2271–83.
173. Wilson KD, Wu JC. Induced pluripotent stem
cells. JAMA 2015;313:1613–4.
activation of endogenous cardiovascular progenitor cells. Circ Res 2012;111:455–68.
165. Braam SR, Tertoolen L, van de Stolpe A,
Meyer T, Passier R, Mummery CL. Prediction of
174. Matsa E, Sallam K, Wu JC. Cardiac stem cell
157. Xiong Q, Ye L, Zhang P, et al. Functional
consequences of human induced pluripotent stem
cell therapy: myocardial ATP turnover rate in the
in vivo swine heart with postinfarction remodeling. Circulation 2013;127:997–1008.
drug-induced cardiotoxicity using human embryonic stem cell-derived cardiomyocytes. Stem Cell
Res 2010;4:107–16.
158. Riegler J, Tiburcy M, Ebert A, et al. Human
engineered heart muscles engraft and survive long
163. Priest BT, Bell IM, Garcia ML. Role of hERG
potassium channel assays in drug development.
166. Jonsson MK, Duker G, Tropp C, et al. Quantified proarrhythmic potential of selected human
embryonic stem cell-derived cardiomyocytes.
Stem Cell Res 2010;4:189–200.
biology: glimpse of the past, present, and future.
Circ Res 2014;114:21–7.
KEY WORDS drug discovery,
human-induced pluripotent stem cells,
macromedicine, micromedicine,
personalized medicine