Role of apoptosis in cardiovascular system

1. APoPToSIS In
cArdIovASculAr
dISorderS
Dr.I.TAMMI RAJU

2. overvIew
• Introduction
• Apoptotic pathways
• Diseases in cvs-apoptosis
• Imaging in apoptosis
• Therapeutic options of apoptosis modulation
• Anti apoptotic drugs
• Set backs of apoptosis
APOPTOSIS IN CVS

3. DEFNITION
• Apoptosis or programmed cell death, is carefully coordinated
collapse of cell, protein degradation , DNA fragmentation
followed by rapid engulfment of corpses by neighbouring
cells. (Tommi, 2002)
• Essential part of life for every multicellular organism from
worms to humans. (Faddy et al.,1992)
• Apoptosis plays a major role from embryonic development to
senescence.
APOPTOSIS IN CVS

4. HISTory of cell deATH /
APoPToSIS reSeArcH
1971 Term apoptosis coined
1977 Cell death genes in C. elegans
1980-82 DNA ladder observed & ced-3 identified
1989-91 Apoptosis genes identified, including bcl-2, fas/apo1 & p53,
ced-3 sequenced
(Richerd et.al., 2001)

5. InTroducTIon
Cell death by injury
-Mechanical damage
-Exposure to toxic chemicals
Cell death by suicide
-Internal signals
-External signals
APOPTOSIS IN CVS

6. wHy SHould A cell commIT
SuIcIde?
Apoptosis is needed for proper development
Examples:
– The resorption of the tadpole tail
– The formation of the fingers and toes of the fetus
– The sloughing off of the inner lining of the uterus
– The formation of the proper connections between neurons in the brain
• Apoptosis is needed to destroy cells
Examples:
– Cells infected with viruses
– Cells of the immune system
– Cells with DNA damage
– Cancer cells
APOPTOSIS IN CVS

7. wHAT mAkeS A cell decIde To commIT
SuIcIde?
Withdrawal of positive signals
examples :
– growth factors
– Interleukin-2 (IL-2)
Receipt of negative signals
examples :
– increased levels of oxidants within the cell
– damage to DNA by oxidants
– death activators :
Tumor necrosis factor alpha (TNF-α)
Lymphotoxin (TNF-β)
Fas ligand (FasL)
APOPTOSIS IN CVS

8. GloSSAry
• Bcl-2 Family Proteins
• This class of proteins shows homology to the C elegans
protein ced-9.
• The first member of this protein family was named B-
cell lymphoma 2 gene (bcl-2.)
• In mammalian species, both proapoptotic and
antiapoptotic members of this protein family have been
characterized.
• Bcl-2 family proteins are localized to the outer
mitochondrial and nuclear membranes and to the
membrane of the endoplasmic reticulum.
APOPTOSIS IN CVS

10. cASPASeS
• cysteine-aspartic proteases or cysteine-dependent aspartate-directed
proteases are a family of cysteine proteases that play essential roles in
apoptosis (programmed cell death), necrosis, and inflammation.
• There are two types of apoptotic caspases:
– initiator (apical/upstream) caspases and
– effector (executioner/downstream) caspases.
• Initiator caspases (e.g., CASP2, CASP8, CASP9, and CASP10) cleave
inactive pro-forms of effector caspases, thereby activating them.
• Effector caspases (e.g., CASP3, CASP6, CASP7) in turn cleave other
protein substrates within the cell, to trigger the apoptotic process.
APOPTOSIS IN CVS

11. APOPTOSIS IN CVS

12. • Death Receptors
• Death receptors are a class of cell membrane receptors
belonging to the larger group of TNF receptors.
• Members of this group comprise Fas, TNFR1, DR3, DR4,
and DR5.
• Fas
• Fas, the prototypical death receptor, mediates apoptotic cell
death after stimulation by Fas ligand.
• Receptor activation involves the recruitment of adaptor
proteins to the cell membrane and subsequent caspase
activation
APOPTOSIS IN CVS

13. • Inhibitor of Apoptosis Proteins
• IAPs are a class of antiapoptotic proteins that were initially
isolated in baculovirus, a virus infecting insect cells.
• Mammalian homologues are believed to inhibit apoptosis by
direct caspase inhibition and by mediating survival signals
after TNFR stimulation.
• p53
• p53 is a transcriptional transactivator protein that is involved
in cell cycle control and DNA repair.
• p53 has been implicated in apoptosis induced by genotoxic
agents and deregulated cell cycle control.
APOPTOSIS IN CVS

14. APoPToSIS:
PATHwAyS
“Extrinsic Pathway”
Death Death Initiator
Ligands Receptors Caspase 8
Effector
“Intrinsic Pathway”
Caspase 3 PCD
DNA Initiator
Mitochondria/
damage Caspase 9
Cytochrome C
& p53
APOPTOSIS IN CVS

15. APOPTOSIS IN CVS
DEATH SIGNALLING PATHWAYS.
• Schematic of Fas death signalling
pathways. Fas, the prototypic
member of the tumour necrosis
factor (TNF) death receptor
family,binds to its cognate ligand.
• Recruitment of the adapter
molecule FADD and pro-caspase 8
results in activation of the latter.
• Caspase 8 activation directly
activates downstream caspases, (3,
6, and 7) which results in DNA
fragmentation and cleavage of
cellular proteins.
• This pathway is thought to occur
in type I cells and does not involve
mitochondrial pathways.

16. APOPTOSIS IN CVS
Mitochondrial death signalling
• Anti-apoptotic members of the Bcl-2 family, pathways
such as Bcl-2 and Bcl-X, are located on the
mitochondrial outer membrane.
• Here they act to prevent the release of
apoptogenic factors from the inner
mitochondrial space.
• Binding of the pro-apoptotic proteins Bid
(after cleavage by caspase 8) or Bad (after
dephosphorylation) to Bcl-2 mitigates the
protective effect of Bcl-2 and triggers release
of cytochrome c and Smac/DIABLO.
• Cytochrome c, in concert with the adapter
protein apaf-1 and caspase 9, activates
caspase 3 and the downstream caspase
cascade.
• Smac/DIABLO inhibits IAPs (inhibitor of
apoptosis proteins), which in turn inhibit
caspase activities, thus propagating apoptosis
• Stimuli such as growth factor withdrawal or
activation of p53 and Fas activation in type II
cells act through this mitochondrial pathway

17. APOPTOSIS IN CVS

18. APOPTOSIS IN CVS

19. reGulATIon of APoPToSIS
• The can be simplified into twomajor Pathways .
• First, membrane bound death receptor of the tumour necrosis receptor
family (TNF-R), such as Fas (CD95), TNF-R1, or death receptors (DR) 3–6,
bind their trimerised ligands
• causing receptor aggregation, and
• subsequent recruitment of adapter proteins (Fas-FADD, TNF-R1 TRADD,
etc) through protein:protein interactions
• adapters recruit cysteine proteases (caspases) such as caspase 8 (FLICE) and
caspase 2 to the complex.14
• Within the complex of Fas, FADD, and caspase 8 (known as the death
inducing signalling complex (DISC)), caspase 8 becomes proteolytically
activated by oligomerisation.15
• This in turn activates the terminal effector caspases (caspases 3, 6, and 7)
responsible for cleavage of intracellular substrates required for cellular
survival, architecture, and metabolic function.
APOPTOSIS IN CVS

20. APOPTOSIS IN CVS
membrane bound death receptor (TNF-R), Fas (CD95), TNF-R1, (DR) 3–6,
bind their trimerised ligands
receptor aggregation
recruitment of adapter proteins (Fas-FADD,
TNF-R1 TRADD
adapters recruit cysteine proteases (caspases) such as caspase
8 (FLICE) and caspase 2 to the complex
activates the terminal effector caspases
(caspases 3, 6, and 7)

21. APoPToSIS vIA mITocHondrIAl
AmPlIfIcATIon
• In addition to direct activation of caspases, caspase 8 activation
causes cleavage of bcl-2 family proteins such as bid (fig 3).
• Bcl-2 family members are either
– pro-apoptotic (Bax, Bid, Bik, Bak) or
– anti-apoptotic (Bcl-2, Bcl-XL).
• Activation of pro-apoptotic Bcl-2 family members causes their
translocation to mitochondria, where they interact with anti-
apoptotic members .
• This interaction depolarises voltage dependent mitochondrial
channels and releases mitochondrial mediators of apoptosis such as
cytochrome c16and Smac/DIABLO.
• The association of cytochrome c with an adapter molecule
apaf-1 and caspase 9 activates caspase 3, and the caspase
cascade.
APOPTOSIS IN CVS

22. • Smac/DIABLO promotes apoptosis by directly
antagonising inhibitor of apoptosis proteins (IAPs).
• Apoptosis can be blocked FLIPs (FLICE inhibitory
proproteins) and IAPs .
• FLIPs have the same pro-domain structure as caspase 8, but do
not have the active caspase site within the C-terminus.
• Binding of FLIP to caspase 8 therefore prevents its activation.
• In contrast, IAPs inhibit the enzymatic activity of
downstream caspases, or they can mediate anti-apoptotic
signalling pathways through the activation of nuclear
transcription factor kb.
APOPTOSIS IN CVS

23. necroSIS vS. APoPToSIS
Necrosis Apoptosis
• Cellular swelling • Cellular condensation
• Membranes are broken • Membranes remain intact
• ATP is depleted • Requires ATP
• Cell lyses, eliciting an • Cell is phagocytosed, no tissue
inflammatory reaction reaction
• DNA fragmentation is random, • Ladder-like DNA fragmentation
or smeared • In vivo, individual cells appear
• In vivo, whole areas of the affected
tissue are affected
APOPTOSIS IN CVS

24. necroSIS vS APoPToSIS
APOPTOSIS IN CVS
Wilde, 1999

25. APOPTOSIS IN CVS

26. APoPToSIS In cArdIAc
develoPmenT
• During cardiac development, programmed cell death was
suggested to be of importance in the formation of septal,
valvular, and vascular structures, implicating the
potential importance of either excessive or inappropriate
apoptosis in congenital heart disease.
• However, so far, direct evidence for an apoptotic cell death
by TUNEL staining has been provided only for
mesenchymal cells in the bulbus cordis of the rat heart at 14
and 16 days of gestation.
APOPTOSIS IN CVS

27. APOPTOSIS IN CVS

28. APoPToSIS And HeArT
fAIlure
• Besides myocyte hypertrophy, myocyte dysfunction due to altered
calcium homeostasis, impaired myofilament Ca21 sensitivity, fiber
slippage, and myocardial fibrosis, progressive loss of cardiomyocytes is
considered to play a major contributory role.
• In canine models of pacing-induced heart failure and heart failure due
to chronic ischemic injury, loss of cardiomyocytes due to apoptosis
was detectable by TUNEL staining, whereas in control myocardium
only rare cardiomyocytes stained positive.
• Narula et al reported that in myocardial specimens from patients
undergoing cardiac transplantation, apoptosis detected by TUNEL
staining was consistently observed in idiopathic dilated
cardiomyopathy but not in ischemic cardiomyopathy.
Narula J, Haider N,
Apoptosis in myocytes in end-stage heart failure.
N Engl J Med. 1996;335:1182–1189
APOPTOSIS IN CVS

29. • Potential mechanisms for the induction of apoptotis
– mechanical factors or
– elevated neurohumoral factors.
• In a model of isometric stretch of papillary muscle,
apoptosis of cardiomyocytes could be detected in
0.64% of cardiomyocytes by TUNEL staining,
indicating that volume overload and elevated end-
diastolic left ventricular pressure may constitute an
initiating event for myocyte apoptosis.
Cheng W, Li B, Kajstura J
Stretch-induced programmed myocyte cell death. J Clin Invest.
1995;96:2247–2259.

30. The cellular basis of pacing-induced dilated cardiomyopathy in canine model:
myocyte cell loss and myocyte cellular reactive hypertrophy. Circulation.
1995;92:2306 –2317
• Kajstura et al observed an increased percentage of apoptotic cells
with angiotensin II treatment. (0.9% apoptotic cells in
angiotensin II–treated cells versus 0.2% in control cells).
• This effect was mediated by AT1 angiotensin II receptors.
• Recently, atrial natriuretic factor (ANF) was shown to
increase the apoptotic index from 4.8% to 19% in isolated neonatal
cardiomyocytes.
• Because ANF levels are elevated in heart failure, sensitivity of
cardiomyocytes to ANF may be of pathophysiological importance.
• ??? ANF is produced at high levels in the atrial and fetal ventricular
myocytes, and there is no evidence of apoptosis so far reported in
these cells in vivo.
APOPTOSIS IN CVS

31. • Vastly different rates of apoptosis have been reported in both
human and animal heart failure, with rates of up to 35.5%.
• While these death rates may be seen only in very localised
areas, given that apoptosis takes less than 24 hours to
complete such rates would result in rapid involution of the
heart.
• More recently, rates of < 0.5% have been consistently
reported in end stage heart failure, which make far more
physiological sense. In addition, in end stage heart failure
necrosis is still (up to seven times) more frequent than
apoptosis.
APOPTOSIS IN CVS

32. • In acute ischemia and reperfusion, apoptosis can be high as 14% in
the area at risk.
• In contrast, the rate of apoptosis associated with chronic stimuli, such
as pressure overload, is ,1% in nontransgenic models when measured
by terminal deoxynucleotidyl transferase–mediated dUTP nick end-
labeling (TUNEL) staining.
• Much lower values for the apoptotic index (0.2% to 0.4%) that are
still 100-fold above control values may therefore more reliably reflect
the overall extent of ongoing myocyte apoptosis in heart failure
Olivetti G, Abbi R, Quaini F,.
Apoptosis in the failing human heart. N Engl J Med. 1997;336: 1131–1141.
APOPTOSIS IN CVS

33. APOPTOSIS IN ARVD
• Numerous cells in the right ventricle of patients with
arrhythmogenic right ventricular dysplasia undergo apoptosis.
• The affected areas had few or no apoptotic cells, whereas
apoptotic nuclei were frequently seen in areas with little
involvement.
• This finding suggests that the loss of myocardial cells through
apoptosis is, at least in part, a primary process that
precedes the filling of acellular space by fat and fibrous tissue in
the absence of an inflammatory reaction.

34. • The triggering factors for apoptotic myocardial cell
death in arrhythmogenic right ventricular dysplasia
remain to be elucidated.
• Some evidence from in vitro and in vivo studies in
animals suggests that hypoxia as well as reperfusion
injury are possible triggers for apoptosis in
cardiomyocytes.
• The presence of myocarditis (and its related
production of inflammatory cytokines) could also have a
role .
APOPTOSIS IN CVS

35. In Situ End-Labeling of Fragmented DNA with TdT
and Biotinylated dUTP.
Cells with fragmented DNA stained brown, whereas cells with
normal nuclei stained blue (immunoperoxidase staining with
hematoxylin counterstaining).

36. Expression of CPP-32 in Right Ventricular Myocardium
from Patients with Arrhythmogenic Right Ventricular Dysplasia
NORMAL ARVD
Immunohistochemical Detection of CPP-32.
Normal right ventricular myocardium does not stain for CPP-32
right ventricular myocardium from
a patient with right ventricular dysplasia stains intensely for CPP-32

37. effecT of vSmc
APoPToSIS
• Vascular smooth muscle cells (VSMCs) within the vessel wall can both
divide and undergo apoptosis throughout life.
• However, the normal adult artery shows very low apoptotic and
mitotic indices.
• In diseased tissue additional factors are present both locally, such as
inflammatory cytokines, inflammatory cells, and the presence of
modified cholesterol, and systemically, such as blood pressure and
flow.
• These factors substantially alter the normal balance of
proliferation and apoptosis, and apoptosis in particular may
predominate in many disease states.
APOPTOSIS IN CVS

38. • The effect of VSMC apoptosis is clearly context dependent.
• Intimal VSMC apoptosis --promote plaque rupture,
• Medial --promote aneurysm formation.
• In neointima formation post-injury, VSMC apoptosis of both
intima and media can limit neointimal formation at a defined
time point.
• However, apoptosis is also associated with a number of
deleterious effects.
• Exposure of phosphatidylserine on the surface of apoptotic
cells provides a potent substrate for the generation of
thrombin and activation of the coagulation cascade,and
apoptotic cells release membrane bound microparticles that
are systemically procoagulant.
• Finally, VSMC apoptosis may be directly pro-inflammatory,
with release of chemoattractants and cytokines from
inflammatory cells.
APOPTOSIS IN CVS

39. • Remodelling
• Remodelling defines a condition in which alterations in vessel
size can occur through processes that do not necessarily
require large changes in overall cell number or tissue mass.
• For example, physiological remodelling by cell
proliferation/apoptosis results in closure of the ductus
arteriosus and reduction in lumen size of infra-umbilical
arteries after birth, and remodelling occurs in primary
atherosclerosis, after angioplasty and in restenosis.
• Although surgical reduction in flow results in compensatory
VSMC apoptosis, the role of VSMC apoptosis per se in
determining the outcome of remodelling is unclear.
APOPTOSIS IN CVS

40. • Arterial injury and aneurysm formation
• Acute arterial injury at angioplasty is followed by rapid
induction of medial cell apoptosis.
• In animal models injury results in medial cell apoptosis 30
minutes to six hours after injury with adventitial and
neointimal apoptosis occurring later.
• In humans, restenosis after angioplasty has been reported to
be associated with either an increase or decrease in VSMC
apoptosis, and again the role of VSMC apoptosis in either the
initial injury or the remodelling process in restenosis in
humans requires further study. Apoptosis of
APOPTOSIS IN CVS

41. ANEURYSM FORMATION
• VSMCs is increased in aortic aneurysms compared with normal
aorta, associated with an increase in expression of a number of
pro-apoptotic molecules.
• In particular, the presence of macrophages and T lymphocytes
in aneurysms suggests that inflammatory mediators released by
these cells may promoteVSMC apoptosis
• Moreover, the production of tissue metalloproteinases by
macrophages may accelerate apoptosis by degrading the
extracellular matrix from which VSMCs derive survival signals
APOPTOSIS IN CVS

42. PLAQUE RUPTURE
• The diminished plaque cellularity of advanced lesions may be
attributed to VSMC apoptosis, and it has been proposed that VSMC
apoptosis eventually contributes to plaque rupture.
• VSMCs cultured from atherosclerotic atherectomy specimens
proliferate more slowly and demonstrate higher frequencies of
apoptosis than VSMCs from normal vessels.
APOPTOSIS IN CVS

43. APoPToSIS In HumAn ATHeroScleroSISAnd reSTenoS
Circulation. Isner JM, Kearney M, Bortman S, Passeri J1995;91:2703–2711.
• In contrast to primary atherosclerotic lesions, where apoptosis was not a
consistent finding in all specimens, almost all atherectomy specimens from
restenotic lesions showed evidence of apoptosis.
• Apoptosis strongly correlated with the presence of intimal hyperplasia.
• In a rat model of balloon vascular injury, apoptosis primarily affected
neointimal smooth muscle cells 7 to 28 days after dilation.
• In contrast, Perlman et al found extensive apoptosis of medial smooth
muscle cells with 70% TUNEL-positive cells as early as 0.5 to 2 hours after
balloon injury.
• The difference in time course between neointimal and medial smooth
muscle cell apoptosis suggests that balloon vascular injury may directly
induce apoptosis In medial smooth muscle cells, whereas apoptosis of
neointimal smooth muscle cells may be associated with the restructuring of
the neointima.
APOPTOSIS IN CVS

44. • Vascular Cell Apoptosis Induced by Acute Balloon Injury
• Apoptotic VSMC death has been documented in numerous animal
models of acute vascular injury.
• Several studies demonstrate that balloon injury of vessels induces
two waves of VSMC apoptosis.
• First wave is a rapid burst of apoptosis in the media occurring
within hours of the injury, resulting in a marked decrease in vessel
wall cellularity. (1-4hrs).
• Although the consequences of early-onset apoptosis in medial
VSMCs are unknown, it could exacerbate neointima lesion
formation at later time points by provoking a greater wound
healing response to overcome the cellular deficit.
APOPTOSIS IN CVS

45. • The second wave of apoptosis occurs at much later times after
injury (days to weeks) and at much lower frequencies.
(confined to the VSMCs of the developing neointima).
• This second wave of apoptosis may limit lesion growth.
• Presumably the rates of neointimal VSMC death and
proliferation are in equilibrium from 2 weeks onward,
thereby preventing any further increase in lesion size.
Han DKM, Haudenschild CC, Hong MK,Tinkle BT, Leon MB, Liau
G. Evidence for apoptosis in human atherogenesis and in a rat
vascular injury. model. Am J Pathol. 1995;147:267–277.
APOPTOSIS IN CVS

46. Pollman MJ, Hall JL, Gibbons GH. Determinants of vascular smooth
muscle
cell apoptosis after balloon angioplasty injury. Circ Res. 1999;84:113–121.
• Rapid balloon angioplasty–induced apoptosis has also been
documented in the rabbit iliac model.
• In this case, increased balloon-to-artery ratios produce
greater frequencies of VSMC apoptosis at early time points,
and this correlates with more acute cell loss.
• The rapid wave of apoptosis resulting from mechanical injury
appears to involve a redox-sensitive pathway, because local
administration of antioxidants will minimize cell loss.
• Surprisingly, VSMCs of the neointima are less sensitive to
rapid-onset apoptosis than are the VSMCs of the underlying
media, suggesting that modulation of the VSMC phenotype
influences angioplasty-induced apoptosis.
APOPTOSIS IN CVS

47. • MOLECULAR CONTROL OF APOPTOSIS AND
VASCULAR CELL VIABILITY
• Apoptosis of VSMCs occurs during developmentally
regulated or pathological vascular remodeling and correlates
with changes in Bcl-2 family protein expression.
• c Bcl-XL and Bcl-2 are essential for VSMC viability.
• c The Fas/FasL system is essential for the inhibition of vessel
inflammation.
• c Fas-mediated cell death may also play a role in atherogenesis
and plaque rupture, but causal data in support of these
hypotheses are lacking.
APOPTOSIS IN CVS

48. reGulATIon of vASculAr SmooTH muScle
cell APoPToSIS
• VSMCs express death receptors, and
• Inflammatory ( interleukin (IL) b (IL-1b), interferon g (IFNg) and tumour
necrosis factor a (TNFa ) cells in plaque express death ligands;
• Interaction between membrane bound ligands and receptors may therefore
induce VSMC death.
• In contrast, soluble ligand binding to death receptors is a very weak inducer
of VSMC apoptosis, and does not induce apoptosis in the absence of
“priming” of the cell.
• Some of this resistance can be explained by intracellular location of death
receptors in VSMCs, and priming may be associated with increased receptor
expression.
• Physiologically, combinations of cytokines increase surface death receptors,
possibly via nitric oxide and p53 stabilisation.
APOPTOSIS IN CVS

49. • This reflects differences in expression of pro- and anti-
apoptotic molecules, regulating, cell:cell and cell:matrix
interactions, and members of the bcl-2 family.
• This may underlie observations that despite (apparently) the
same stimulus for apoptosis, VSMC apoptosis in either normal
or diseased vessels wall is highly localised.
• Indeed, insulin-like growth factor 1 receptor concentrations
(IGF-1R), a potent survival signalling system for normal
VSMCs, are downregulated in plaque VSMCs.
APOPTOSIS IN CVS

50. APoPToSIS In IScHemIc
HeArT dISeASe
• Saraste A, Pulkki K, Kallajoki M, Henriksen K, Parvinen M,Voipio-
Pulkki LM. Apoptosis in human acute myocardial infarction.
Circulation.1997;95:320
• Although myocardial infarction was long considered to be characterized by
nonapoptotic (“necrotic”) cell death due to the breakdown of cellular energy
metabolism, there is growing evidence that myocyte loss during the acute
stage of myocardial infarction involves both apoptotic and nonapoptoticcell
death.
• In human postmortem studies of myocardial infarction, apoptotic
cardiomyocytes appeared to be predominantly localized in the hypoperfused
border zone between the central infarct area and noncompromised
myocardial tissue.
• InterestinglyI, myocytes in the peri-infarct region were shown to upregulate
the apoptotic regulatory proteins bax and bcl-2.
• In addition, myocytes showing evidence of DNA degradation, chromatin
condensation, and cell fragmentation were detected in human hibernating
myocardium. APOPTOSIS IN CVS

51. APOPTOSIS IN CVS
Apoptosis in STEMI. Myocytes at the infarct border in this
specimen demonstrate nuclear staining by the nick-end labeling
technique (arrow) suggesting that they have undergone
apoptosis

52. • APOPTOSISI IN HIBERNATING MYOCARDIUM
• Apoptosis is particularly prominent during the transition
from chronically stunned to hibernating myocardium(loss of
30% of regional myocytes).
• Vanoverschelde and coworkers have previously described
light microscopic and ultrastructural characteristics of
hibernating myocardium from transmural biopsies, which
are characterized by small increases in interstitial
connective tissue, myofibrillar loss (myolysis), increased
glycogen deposition, and minimitochondria.
• Some studies have demonstrated upregulation of
cardioprotective mechanisms in response to repetitive
reversible ischemia, which may be operative in minimizing
myocyte cell death and fibrosis in the chronic setting.
APOPTOSIS IN CVS

53. • An interesting mechanism potentially linking altered
metabolism and protection is the regional downregulation of
glycogen synthase kinase-3β , which can ameliorate cell
death and also explains the increased tissue glycogen in
hibernating myocardium.
• In experimental studies in animals without heart failure,
antiapoptotic and stress proteins such as HSP-70 have
been found to be upregulated whereas increased
proapoptotic proteins and a profile of progressive cell death
and fibrosis have been reported in human biopsies of patients
with hibernating myocardium and heart failure
APOPTOSIS IN CVS

54. • Ischemia is associated with multiple alterations in the
extracellular and intracellular milieu of cardiomyocytes that
may act as inducers of apoptosis
• A p53-mediated mechanism for myocyte apoptosis under
hypoxic conditions was suggested.
• The death receptor Fas is markedly upregulated in
cardiomyocytes during ischemia and hypoxia, and
cardiomyocytes may thus become susceptible to apoptotic
cell death by interaction with FasL.
• Whereas under control conditions ,1% of cardiomyocytes
expressed the Fas antigen, Fas was detectable in 50% of
cardiomyocytes within a few hours of ischemia and
ischemia/reperfusion.
Tanaka M, Ito H, Adachi S Hypoxia induces apoptosis with enhanced
expression of Fas antigen. Circ Res. 1994;75:426–433
APOPTOSIS IN CVS

55. • observation in animal models of myocardia infarction suggest that
apoptosis may contribute substantially to cell death even within the
central infarct area with 5% to 33% of the cardiomyocytes staining
positive for DNA fragmentation.
• Treatment with the caspase inhibitor zVAD.fmk led to a reduction in
infarct size and an improvement of acute functional parameters.
• However, these measurements were obtained 24 hours after
infarction, and it is not known whether the beneficial effects of
zVAD.fm persists in the chronic stage
APOPTOSIS IN CVS

56. REPERFUSION INJURY
• The role of apoptosis in reperfusion injury has recently been
addressed in rat and rabbit animal models, where reperfusion was
shown to accelerate the occurrence of apoptotic cell death in
cardiomyocytes.
• Because the formation of reactive oxygen species has been implicated
as one of the pathomechanisms for tissue injury during reperfusion,
the recent finding that oxidative stress induces apoptosis in isolated
neonatal rat ventricular cardiomyocytes may provide an important
mechanistic link between reperfusion and tissue injury.
Fliss H, Gattinger D. Apoptosis in ischemic and reperfused rat myocardium.
Circ Res. 1996;79:949 –956.
APOPTOSIS IN CVS

57. REMODELING
• In addition, apoptotic cell death may have a role in the
remodeling of noninfarcted myocardium, as evidenced in
human myocardial specimens sampled within 10 days
aftermyocardial infarction.
• In myocardium remote from the infarcted area, 0.7% of the
cardiomyocytes were apoptotic, whereas in control hearts no
myocyte apoptosis was detectable.
• Interestingly, apoptosis in noninfarcted regions of myocardium
was inhibited by overexpression of IGF-1 in a transgenic
mouse model, resulting in reduced ventricular dilation and
wall stress 7 days after infarction.
Li Q, Li B, Wang X, Overexpression of IGF-1 in mice
protects from myocyte death after infarction, attenuating ventricular
dilation, wall stress, and cardiac hypertrophy. J Clin Invest. 1997;100:
.
APOPTOSIS IN CVS

58. Apoptosis and Atherosclerosis
Bjorkerud S, Bjorkerud B. Apoptosis is abundant in human atherosclerotic
lesions,. Am J Pathol. 1996;149:367–380.
• Apoptosis may prove to play an essential role in
atherosclerotic alterations of the vessel wall.
• In atherosclerotic lesions widespread apoptosis was
detectable by TUNEL staining (up to 43% of cells in the lipid-
rich core of atheromata.
• A substantial number of cells undergoing apoptosis were
immunoreactive with a polyclonal antiserum directed against
caspase-1 and -3.
• Remarkably, apoptosis did not occur in medial smooth
muscle cells
.
APOPTOSIS IN CVS

59. Isner JM, Kearney M, Bortman S, Passeri J. Apoptosis in human atherosclerosis
and restenosis. Circulation. 1995;91:2703–2711.
• In contrast to primary atherosclerotic lesions, where apoptosis was not a
consistent finding in all specimens, almost all atherectomy specimens from
restenotic lesions showed evidence of apoptosis.
• Apoptosis strongly correlated with the presence of intimal hyperplasia.
• In a rat model of balloon vascular injury, apoptosis primarily affected
neointimal smooth muscle cells 7 to 28 days after dilation.
• In contrast, Perlman et al found extensive apoptosis of medial smooth
muscle cells with 70% TUNEL-positive cells as early as 0.5 to 2 hours after
balloon injury.
• The difference in time course between neointimal and medial smooth
muscle cell apoptosis suggests that balloon vascular injury may directly
induce apoptosis In medial smooth muscle cells, whereas apoptosis of
neointimal smooth muscle cells may be associated with the restructuring of
the neointima.
APOPTOSIS IN CVS

60. Bennett MR, Evan GI, Schwartz SM.
Apoptosis of rat vascular smooth
muscle cells is regulated by p53-dependent and -independent
pathways.
• Vascular smooth muscle cells undergo p53-
Circ Res. 1995;77:266 –273.
dependent apoptosis after overexpression of the
positive cell cycle regulators c-myc or E1A.
• Interestingly, isolated vascular smooth muscle cells
from human atherosclerotic plaques were shown to
have a higher propensity for both spontaneous
apoptosis and apoptosis induced by overexpression
of p53 compared with vascular smooth muscle cells
from normal vessels.
APOPTOSIS IN CVS

61. ALTERNATIVE MECHANISM
• An alternative mechanism may involve the induction of apoptosis by a
death receptor– dependent mechanism.
• Twenty percent of Fas-positive cells showed evidence for
internucleosomal DNA fragmentation with associate,morphological
features of apoptosis, like chromatin condensation and nuclear
fragmentation.
• The cytokines(interleukin-1 and TNF-a) increase both the fraction of
Fas-expressing cells to '90% of all cells and the density of Fas antigen
on individual cells.
• Interestingly, the combination of g-interferon, interleukin-1, and
TNF-a alone already exerted a proapoptotic effect on cultured
smooth muscle cells that may involve both No dependent and
-independent mechanisms.
APOPTOSIS IN CVS

62. • Activation of immune cells may involve oxidized low-density
lipoprotein (LDL) particles, the cell surface receptor CD40, and its
cognate ligand.
• One major clinical implication of apoptotic cell death in
atherosclerotic lesions may be a reduced plaque stability.
• In addition to proteolysis, loss of smooth muscle cells in the fibrous
cap of atherosclerotic lesions is known to predispose the lesions to
plaque instability and therefore may increase the risk of unstable
angina pectoris and acute myocardial infarction.
• In this respect, it is noteworthy that the death receptor Fas is
expressed on as many as two thirds of the cells in the fibrous cap in
human atherosclerotic lesions.
APOPTOSIS IN CVS

63. Dimmeler S, Haendeler J, Galle J, Zeiher AM. Oxidized LDL induces apoptosis of
human endothelial cells :a mechanistic clue to the “response to injury”
hypothesis. Circulation. 1997;95:1760 –1763
• In recent studies, a potential role of oxidative mechanisms has been
suggested in the apoptosis of vascular cells.
• Cultured endothelial cells undergo apoptosis in response to oxidized LDL,
indicating a potential role for apoptosis in the early phases of atherogenesis
• Sensitivity to oxidized LDL could be reduced by nitric oxide or by calcium
channel blockers.
 Escargueil-Blanc I, Meilhac O. Oxidized LDLs induce massive apoptosis through a calcium-
dependent pathway: Arterioscler ThrombVasc Biol. 1997;17:331–339.
• In addition, apoptosis of vascular smooth muscle may at least partly be
attributable to oxidant damage by hydrogen peroxide.
 Li PF, Dietz R, von Harsdorf R. Differential effect of hydrogen peroxide and superoxide anion on
apoptosis and proliferation of vascular smooth muscle cells. Circulation. 1997;96:3602–3609.
• exposure of phosphatidylserine on the surface of apoptotic cells can promote
thrombin generation.
APOPTOSIS IN CVS

64. oTHer cArdIovASculAr
dISeASeS
• Apoptosis due to immune mechanisms may be of major
importance in myocarditis and cardiac allograft rejection.
• Indeed, in a rat model of heterotopic heart transplantation,
Szabolcs et al found extensive apoptosis of cardiomyocytes,
endothelial cells, and infiltrating leukocytes.
• Infiltrating cells consisted initially of lymphocytes, whereas
macrophages predominated in later stages, when apoptosis
was prominent.
• It is not known to which extent apoptosis is induced by
cytotoxic T lymphocytes through Fas-dependent or granzyme
B–dependent mechanisms.
APOPTOSIS IN CVS

65. • Cardiomyocytes express a functional TNFR1 and can undergo
apoptosis after stimulation with TNF-a in vitro.
• Interestingly, TNF-a was shown to be produced in
myocardium, although the cell type was not clearly defined.
• When TNF-a was highly overexpressed under the control of a
strong cardiomyocyte-specific promoter, a phenotype of
dilated cardiomyopathy was induced in transgenic mice.
• Likewise, in an animal model of myocarditis, TNF-a was
shown to exert a major role in the pathogenesis of myocardial
inflammation, although it is not clear in how far TNF-a–
mediated apoptosis contributed to myocardial damage.
APOPTOSIS IN CVS

66. • Excessive apoptosis of the cardiac conduction
system was suggested to be a possible mechanism in
the pathogenesis of heart block.
• On the other hand, incomplete apoptotic cell
deletion has been postulated to cause the persistence
of accessory atrioventricular conduction pathways,
such as in Wolff-Parkinson-White syndrome.
APOPTOSIS IN CVS

67. ATrIAl fIBrIllATIon
• Apoptosis (programmed cell death) is
another likely contributor to the Staining of tissue sections with the TUNEL
structural substrate of AF.
• Both the pro- and activated forms of
CASP-3 were detected in
diseased myocardial samples, which N
also showed stronger CASP-3
expression than controls.
• Expression of the antiapoptotic
BCL-2 protein was decreased in
diseased atria.
• Although there is no apoptosis in the
goat model after 19 to 23 weeks of
AF, small numbers of apoptotic cells AF
are identifiable in chronically
fibrillating human atria.
• These cells are likely to be lost
structurally and functionally when
apoptosis is complete, causing
irreversible atrial damage.
Aime-Sempe C,, et al. Myocardial cell death in fibrillating and dilated human right
atria. J Am Coll Cardiol. 1999

68. ASSAyS for APoPToSIS
• The gold standard for identification of apoptotic cells is
ultrastructural evidence of chromatin condensation, the
earliest characteristic morphologic feature.
• However, although ultrastructural evidence of chromatin
condensation is highly reliable, the routine use of electron
microscopy to detect chromatin condensation is impractical
because it is labor-intensive and costly.
• The terminal deoxynucleotidyl transferase (TUNEL) method
is the most widely used technique because the microscopic
evaluation of myocardial samples is relatively easy and
inexpensive .
• The TUNEL method uses a molecular probe that anneals to
DNA with double-stranded breaks characteristic of apoptosis
(i.e., with 3′ overhangs).
• The Taq polymerase method follows a similar principle.
APOPTOSIS IN CVS

69. • TUNEL technique not only labels apoptotic nuclei but can
also label necrotic and oncotic nuclei as well as nuclei
undergoing DNA repair. Similar limitations apply to the Taq
polymerase method, albeit to a lesser extent.
• TUNEL staining and morphometry are laborious, and the
duration of apoptotic cells being detectable by TUNEL may
last only a few hours.
• DNA laddering, though specific, is not quantitative and
sensitive in tissue samples, where a small number of cells
(1%) are undergoing apoptosis.
APOPTOSIS IN CVS

70. APOPTOSIS IN CVS
NONINVASIVE IMAGING OF APOPTOSIS

71. nonInvASIve ImAGInG of APoPToSIS In
cArdIovASculAr dISeASe
1. Atherosclerosis
Kietselaer BL, Reutelingsperger
Noninvasive detection of plaque instability with use of radiolabeled annexin A5
N Engl J Med 2004;350(14):1472–1473. [PubMed: 15070807]
• Molecular imaging of atherosclerosis is an area of intense
research.
• One area of extensive investigation utilizes 99mTc-radiolabeled
annexin V for SPECT imaging.
• Using annexin V-enhanced micro-SPECT combined with
subsequent micro-CT, murine atheroma models demonstrated
excellent correlation between noninvasive and histopathological
assessment of macrophage infiltration and the extent of
apoptosis
APOPTOSIS IN CVS

72. • Radiolabeled annexin V has also demonstrated applicability to
clinical imaging of apoptosis in carotid atherosclerosis.
• In a pilot clinical study, 99mTc SPECT imaging demonstrated
higher uptake in carotid artery plaques of patients with recent TIA
or stroke symptoms compared to patients with remote symptoms.
• Resected endarterectomy specimens validated this difference,
showing significantly greater immunoreactive annexin V staining of
histological sections .
• Ultimately, clinical noninvasive imaging of apoptosis within
atherosclerosis might provide not only a risk assessment at a single
time point, but also be able to assess the effectiveness of local or
systemic therapies that stabilize plaques and reduce coronary risk.
Noninvasive imaging of atherosclerotic lesions in apolipoprotein E-deficient and low-
densitylipoprotein receptor-deficient mice with annexin A5. J Nucl Med 2006;
APOPTOSIS IN CVS

73. • TO this end, Hartung and colleagues randomized
balloon injured rabbits to high cholesterol diet
(HCD), HCD for three months followed by one
month of standard chow, and HCD for three months
followed by HCD with statin treatment.
• Noninvasive imaging using radiolabeled annexin V
demonstrated maximum signal in untreated HCD
animals, with significantly less signal in the HCD
withdrawal and statin-treated groups [25].
APOPTOSIS IN CVS

74. 2.myocArdIAl
IScHemIA/rePerfuSIon Injury
Dumont EA, Reutelingsperger CP,
Real-time imaging of apoptotic cell-membrane changes at the single-cell level in the beating murine
heart. Nat Med 2001;7(12):1352–1355.
• Real -time intravital microscopy of fluorescently conjugated
annexin V to individual myocytes following ischemia-reperfusion
injury showed detailed study of the kinetics of apoptosis in the
ischemia-reperfusion injury.
• Apoptosis imaging has shed light on the spatial and temporal
evolution of apoptosis in models of ischemia-reperfusion injury.
• In a rat model of ischemia-reperfusion injury, autoradiography of
resected hearts following 99mTcradiolabeled annexin V
administration revealed that the zone of apoptosis initially begins
in the mid-myocardium 30 min after reperfusion, extends into
the subendocardium and subepicardium 6 h after reperfusion, and
then eventually regresses over 3 days .
APOPTOSIS IN CVS

75. moleculAr mr
ImAGeS
• Molecular MR images can be correlated
with MR images of myocardial function,
contractility, strain, perfusion and viability in a
single integrated dataset.
• In a recent highresolution, noninvasive
MR imaging approach, a novel annexinV-
based magnetofluorescent iron oxide
nanoparticle was used to quantitatively
image myocardial apoptosis .
• Cine MRI of the mouse heart allowed the
molecular image of cardiomyocyte
apoptosis to be correlated with global left
ventricular function as well as regional
myocardial contractility
• The distribution of the
magnetofluorescent annexin suggested a
midmyocardial predominance of the
agent, in accordance with prior
observations by other investigators Taki J, Higuchi T, Kawashima A, Tait JF, Kinuya S
. Detection of cardiomyocyte death in a rat model of ischemia and reperfusion using
99mTc-labeled annexin V. J Nucl Med 2004;45(9):1536–1541

76. Magnetic resonance imaging of cardiomyocyte apoptosis with a novel
magneto-optical nanoparticle.
Magn Reson Med 2005
• The dual modality nature of the probe allowed the in vivo MRI
findings to be confirmed by ex vivo fluorescent imaging .
• The results of this study show that high-resolution serial
quantitative imaging of cardiomyocyte apoptosis can be
performed in vivo by MRI.
• In addition the molecular MR image could be integrated with MR
images of myocardial function in a single integrated dataset.
• Further integration of molecular MR images of cardiomyocyte
apoptosis with MR images of myocardial perfusion and
viability would be highly feasible and demonstrate the breadth and
flexibility of a molecular MR approach to apoptosis imaging.
• The utility of this agent in vivo, however, remains to be
determined
APOPTOSIS IN CVS

77. APOPTOSIS IN CVS
ScInTIGrAPHIc ImAGInG AGenTS
• SPECT imaging of radiolabeled 99mTc annexin V at two time
points post-infarction; images showed increased uptake in
infarcted areas with a matching perfusion defect
• Noninvasively imaging the extent of apoptosis resulting from
acute coronary syndromes could be an important tool to help
guide
1. Revascularization strategies,
2. Optimize heart failure therapies, and
3. Identify patients for emerging anti-apoptotic specific agents,
4. Preventing left ventricular dysfunction,
5. Monitoring ventricular remodeling following injury,and
6. Identifying patients at high risk for future cardiac events.
Visualisation of cell death in vivo in patients with acute myocardial
infarction. Lancet 2000

78. APOPTOSIS IN CVS
Imaging of cardiomyocyte apoptosis in acute myocardial infarction with 99mTc-annexin V.
Combination of acute 99mTc-MIBI and 99mTc annexin V. 99mTc-MIBI perfusion
defects in anteroseptal and apical region (open arrows) correlate well with 99mTc-annexin
V
activity (grey arrows).

79. 3.HeArT fAIlure And
myocArdITIS
• One model utilizes mice genetically engineered to overexpress
Gαq, a subunit of the cell-surface receptors involved in promoting
cardiac myocyte hypertrophy (α1-adrenergic receptor, angiotensin
II type 1 receptor, and endothelin-1 receptor.
• the magnetofluorescent nanoparticle AnxCLIO-Cy5.5 has been
used to image apoptosis in vivo in postpartum Gaq overexpressing
mice by MRI .
• The ability to successfully image apoptosis in this model of heart
failure shows that AnxCLIO-Cy5.5 crosses an intact capillary
membrane, penetrates the interstitium of the myocardium, and
detects relatively low levels of apoptosis in vivo.
Inhibition of cardiac myocyte apoptosis improves cardiac function and abolishes mortality in
theperipartum cardiomyopathy of Galpha(q) transgenic mice.
Circulation 2003;108(24):3036–3041
APOPTOSIS IN CVS

80. 4.AcuTe HeArT fAIlure
• Recently, a rat model with systemic inflammatory response
syndrome was used to demonstrate cardiomyocyte apoptosis by
uptake of radioiodinated annexin V .
• In a rat model of subacute catecholamine-induced myocarditis,
99mTc-labeled annexin V showed increased uptake compared to
control animals and showed a strong correlation with
imuunohistochemical evidence of apoptosis .
Annexin V detection of lipopolysaccharide-induced cardiac
apoptosis.
Shock 2007;27(1):69–74.
APOPTOSIS IN CVS

81. CLINICAL APPLICATIONS
• This finding lays the groundwork for clinical imaging of
apoptosis in myocarditis, a technique that would offer great
benefit in
1. confirming the diagnosis of myocarditis,
2. determining the extent of involvement,
3. selecting patients for anti-apoptotic therapies, and
4. potentially identifying patientswith a heavy disease
burden that may benefit from ventricular-assist devices
as a bridge to recovery or transplant.
APOPTOSIS IN CVS

82. 5.cHemoTHerAPeuTIc-relATed
cArdIoToxIcITy
Yeh ET, Tong AT, Lenihan DJ, Yusuf SW,
AA, Ewer MS. Cardiovascular complications of cancer therapy: diagnosis
management. Circulation 2004;109(25):3122–3131.
• Chemotherapeutic-related cardiotoxicity remains a significant
clinical problem, and there is an unmet need to identify susceptible
patients .
• Current clinical approaches utilize serial determinations of left
ventricular ejection fraction to identify cardiotoxicity.
• In a rat model of doxorubicin cardiotoxicity, radiolabeled annexin
V was able to detect high levels of cardiomyocyte apoptosis .
• Ultimately, this approach could serve as a more sensitive early
marker of anthracylicne toxicity than studies based on macroscopic
left ventricular dysfunction, providing the opportunity to modify
or stop administration of the agent before clinically overt heart
failure.
APOPTOSIS IN CVS

83. 6.cArdIAc TrAnSPlAnT
rejecTIon
Annexin-V imaging for noninvasive detection of cardiac allograft rejection.
Nat Med 2001;7 (12):1347–1352.
• Current monitoring of cardiac allograft rejection relies heavily on
endomyocardial biopsy, an invasive procedure with attendant risks.
• Allograft rejection is characterized by varying degrees of
inflammation with associated necrosis and apoptosis.
• Apoptosis imaging therefore has the potential to noninvasively
identify patients with transplant rejection and monitor response to
immune modulation therapy.
• Early efforts with a rat model of cardiac allograft rejection showed
increased uptake of 99mTc annexin V that correlated well with
histologic evidence of apoptosis associated with a mononuclear
inflammatory infiltrate.
APOPTOSIS IN CVS

84. • In a separate study of 10 transplant recipients using radiolabeled
annexin V, two patients with moderate acute rejection by biopsy were
correctly identified by SPECT imaging; however,specificity in this
study was suboptimal with half of the patients with grade IA rejection
or less having two foci of uptake on imaging .
• With further refinements, these encouraging clinical efforts may
reduce the need for routine surveillance endomyocardial biopsy in
transplant recipients.
In vivo imaging of acute cardiac rejection in human patients using (99 m)technetium
labeled annexin V. Am J Transplant 2001;1(3):270–277
APOPTOSIS IN CVS

85. Diffuse myocardial uptake of 99mTc-annexin V in cardiac allograft
rejection.
SPECT imaging
3 h after intravenous injection of radiolabeled annexin V demonstrated diffuse
myocardial
uptake of radiotracer, suggesting extensive apoptosis in the myocardium and transplant

86. fuTure of ImAGInG
• Whereas current clinical practice focuses on cardiac
biomarkers that reflect cardiomyocyte lysis well after the
damage is complete, apoptosis imaging provides a window
onto areas with ongoing cellular damage that presages
functional and structural impairment.
APOPTOSIS IN CVS

87. THerAPeuTIc oPTIonS for
APoPToSIS
• Apoptosis can be interrupted at many points in the signalling
pathway.
• Prevention of apoptotic myocyte death may be directed at
(1) inhibiting/preventing the stimulus,
(2) inhibiting the regulatory mechanisms determining the decision to
die, or
(3) inhibiting the pathways executing apoptosis.
• Clearly, many signalling pathways are activated in ischaemia
and heart failure.
• Interruption of a single pathway may therefore not inhibit
apoptosis if there are multiple, redundant pathways inducing
apoptosis.
APOPTOSIS IN CVS

88. INHIBITING/PREVENTING THE PRO-APOPTOTIC
STIMULUS.
• The beneficial effects of B-blockers in chronic heart failure
and ischaemic heart disease may counteract the pro-
apoptotic effect of excess catecholamines.
• Indeed, carvedilol can inhibit ischaemia/reperfusion
induced myocyte apoptosis, and
• Angiotensin converting enzyme inhibitors may protect
against angiotensin II induced apoptosis.
APOPTOSIS IN CVS

89. PROTECTION AGAINST APOPTOSIS
• Many molecules protect cells from apoptosis, including
1. Anti-apoptotic Bcl-2 family members,
2. IAPs, and
3. Decoys for death receptors.
• Although these agents inhibit apoptosis mediated by many
stimuli, and may therefore be clinically useful, at present they
cannot be selectively expressed without gene transfer into the
heart, with all its inherent problems.
• More promising is the potential administration of soluble
survival factors following the apoptotic stimulus.
APOPTOSIS IN CVS

90. • Many growth factors, including IGF-1, cardiotrophin-1, and the
neuregulins, inhibit apoptosis following ischaemia, serum withdrawal,
myocyte stretch, and cytotoxic drugs.
• OVEREXPRESSION OF IGF-1 reduces apoptosis in non-infarcted
remote zones and promotes favourable remodelling postmyocardial
infarction. (AKT pathway)
• Activation of the CARDIOTROPHIN-1 receptor also inhibits cardiac
dilatation following aortic banding, suggesting that reduced
cardiomyocyte apoptosis can be translated into improved function.
(ERK pathways)
APOPTOSIS IN CVS

91. HEART FAILURE
• Heart failure is characterised by increased plasma
concentrations of catecholamines and TNFa.
• The beneficial effects of b blockers in heart failure may
therefore be achieved by prevention of myocyte apoptosis.
• Licensed inhibitors of TNFa are now available, although recent
randomised controlled trials (RENAISSANCE and
RECOVER) suggest that a soluble TNF receptor antagonist
(etanercept) does not benefit patients with heart failure.
• In contrast, evidence identifying the type 2 angiotensin II
receptor as inducing apoptosis in models of heart failure has
suggested that its inhibition may be beneficial.
APOPTOSIS IN CVS

92. PREVENTING EXECUTION OF APOPTOSIS
• Augmentation of endogenous inhibitors of caspases, such as
the IAPs, could therefore inhibit apoptosis induced by many
stimuli.
• Pharmacological inhibition of caspases using cell permeable
analogues of cleavage sites can inhibit myocyte apoptosis over
the short term.
• However, their long term benefits are unknown, as cells that
are destined to die may do so anyway, and delaying apoptosis
may not provide long term benefit.
APOPTOSIS IN CVS

93. APOPTOSIS IN CVS

94. APoPToSIS And STATInS
• Conclusions
• The present results suggest that protein prenyl-ation
inhibition by statins may be involved in statin-induced
VSMC apoptosis.
• These data provide a new potential mechanism by
which statins may modulate the evolution of
atherosclerotic lesions.

95. APOPTOSIS IN CVS

96. • ACE inhibitor decreases the degradation of bradykinin,
(B2receptor-dependent pathway) which may have an
important role in the antiapoptotic effect of the ACE inhibitor.
• ACE inhibitors reduce myocardial apoptosis, as indicated by a
– reduction in TUNEL-positive myocytes,
– suppression of DNA ladder formation, and
– attenuation of caspase-3 activation
– preservation of the Bcl-xL protein by ACE inhibition may have a
role in the decrease in myocardial apoptosis.
These findings may have important clinical implications in
cardioprotective treatment with ACE inhibition
APOPTOSIS IN CVS

97. ACEI AND APOPTOSIS
• Long -term treatment with theACE inhibitor enalapril in dogs with moderate
HF attenuates cardiocyte apoptosis as evidenced by reduced cardiomyocyte
nDNAf events in viable myocardial regions that border scar tissue (old
infarcts).
• The attenuation of cardiomyocyte apoptosis with ACE inhibition therapy was
associated with prevention of progressive LV dysfunction and attenuation of
LV chamber remodeling.
• Reduction of ongoing loss of functional cardiac units in HF through apoptosis
may be one mechanism by which ACE inhibitors preserve LV function and
attenuate the progression of LV chamber remodeling in the failing heart.

98. EFFECT OF VASOPEPTIDASE INHIBITOR, OMAPATRILAT
ON CARDIOMYOCYTE APOPTOSIS AND LV REMODELLING.
• In this study, both omapatrilat and captopril decreased
apoptosis in the border zone of the infarct but also to a
lesser extent in the remote non- inhibition infarcted area.
• In contrast, selective NEP inhibition did not affect the
number of apoptotic cells.
• AT II has been earlier Cellular basis of chronic ventricular
remodeling after myocardial infarction in rats but the
precise mechanism is unknown.
APOPTOSIS IN CVS

99. APOPTOSIS IN CVS
Omapatrilat and captopril reduced fibrosis
as measured 4 weeks after MI
The amount of cardiomyocyte apoptosis in
the border and remote zones of the LV 4
weeks after operation

100. APOPTOSIS IN CVS
The VPI omapatrilat, with its combination of NEP and ACE inhibition,
suppresses cardiomyocyte apoptosis post-MI and in neonatal cultured rat
cardiomyocytes more than the ACEI captopril, but this does not result in
significant hemodynamic or morphologic differences between
omapatrilat and captopril

101. APOPTOSIS AND ARB
• Blockade of angiotensin II type 1 receptor (AT1) signaling
attenuates heart failure following myocardial infarction (MI),
perhaps through reduction of fibrosis in the noninfarcted
myocardium
• Ten days post-MI, apoptosis among granulation tissue cells was
significantly suppressed in the olmesartan-treated heart.
• olmesartan dose-dependently inhibited Fas-mediated apoptosis
in granulation tissue-derived myofibroblastss
APOPTOSIS IN CVS

102. • Metabolically active agents such as glucose-insulin-
potassium, trimetazidine and ranolazine that protect
from ischemia, increase glucose metabolism relative to
that of fatty acids.
• By promoting glycolysis they tend to close the ATP-
dependent potassium channels that help to mediate
preconditioning.
• By lessening the oxygen-wasting effects of fatty acids,
they are mitochondrial protective and oxygen-sparing.
• These qualities should help in the therapy of myocardial
ischemia and also heart failure.
APOPTOSIS IN CVS

103. RANOLAZINE
• Agents that reduce the harmful effects of reactive oxygen
may protect the heart against ischemia-reperfusion damage.
• In fact, antioxidants have been demonstrated to attenuate
both lipid peroxidation and myocardial damage in the
ischemia-reperfused heart
• Ranolazine reduce H2O2-induced derangements may
contribute to its cardioprotective effect against ischemia-
reperfusion damage.
APOPTOSIS IN CVS

104. • The contribution of the ubiquitin– proteasome system
is the formation and growth of the lipid core through
inflammation,apoptosis,cell proliferation.
• Inhibitors of U-P system may help prevent
atherosclerosis.
APOPTOSIS IN CVS

105. decreASed APoPToSIS followInG
SucceSSful ABlATIon of ATrIAl
fIBrIllATIon.
• Twenty-five patients with AF were prospectively studied.
• The success of the ablation was assessed clinically and with
3 Holter recordings.
• Blood samples were drawn before surgery, and at 3 and 6
months after.
• Serum concentrations of Fas ,TRAIL were measured using
ELISA.
• The ablation of AF is associated with decreased serum
markers for apoptosis.
APOPTOSIS IN CVS

106. cAlPAIn InHIBITor In A cAnIne rAPId
ATrIAl fIBrIllATIon model.
• The calpain is a calcium-dependent, non lysosomalcysteine
proteases (proteolytic enzyme.)
• Activation of of calpain participate in the structural
remodeling of left atrial cardiac muscle and contractile
dysfunction.
• Calpain inhibitor suppresses the increased calpain activity and
reverses the structural remodeling of sustained atrial
fibrillation.
• Calpain inhibition may therefore provide a possibility for
therapeutic intervention in AF.
• The calpain inhibitor N-Acetyl-Leu-Leu-Met attenuated
apoptosis through a complicated network of apoptosis-related
proteins, which may result in improvement of structural
remodeling in atrial fibrillation.
APOPTOSIS IN CVS

107. APOPTOSIS IN CVS

108. APOPTOSIS IN CVS
Ocimum sanctum,withania somnifera,curcuma longa

109. SeT BAckS of APoPToSIS
• It is important to determine whether apoptosis is one of
the early causes rather than a terminal event that is
associated with the end stage of these disease entities.
• The true incidence of apoptosis is not clear.
• The initiating stimuli of apoptosis in myocardial and
vascular cells at the cellular level are not well
understood
• With respect to the clinical situation,the role of
apoptosis as a prognostic marker deserves further study.
APOPTOSIS IN CVS

110. • Although pharmacological caspase inhibition
prevents myocyte apoptosis induced by ischemia and
reperfusion in short-term experiments, the ultimate
fate of the cells is not clear.
• It is not known whether ischemic myocytes that
have initiated the apoptosis pathway and are acutely
rescued by caspase inhibition will eventually survive
or whether the drug simply delays cell death.
APOPTOSIS IN CVS

111. concluSIonS
• Taken together, apoptosis increasingly penetrates the
field of cardiovascular research. Several exciting
hypotheses need to be tested to determine whether the
opportunities offered in the modulation of apoptotic cell
death will finally translate into new treatment
approaches for cardiovascular disease.
APOPTOSIS IN CVS