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Midollare del surrene e disfunzione
autonomica
Giuseppe Rengo, MD, PhD
Department of Translational Medical Sciences
University of Naples “Federico II”
Salvatore Maugeri Foundation
Scientific Institute of Telese Terme – IRCCS –
Haider N et al. J A C C C a r d i o v a s c u l a r I m a g i n g 2010
Adrenergic Excess, hNET1 Down-Regulation,
and Compromised mIBG Uptake in Heart Failure
Rengo G et al. J Gerontol A Biol Sci Med Sci submitted 2015
Impact of aging on cardiac sympathetic innervation measured
by 123I-mIBG imaging in patients with heart failure
CARDIOMYOCYTE
extracellular
intracellularACβ-AR
β γ
PKA
ATP cAMP
CA CACA
CA
CA CA
CA
CA
CACA
P
GRK2
contractility
Endocytosis and
degradation
Physiologic conditions
Gsα
Heart Failure
CA
CA
CA
CA
CA
CA CA
CACA
CA
CA
CA
CA
CA
Positive
inotropy(βARKct
β-blocker
Exercise Training)
SNS Hyperactivity
Myocardial oxigen consumption (J Mol Cell Cardiol 1985);
Cardiac interstitial fibrosis (Eur J Pharmacol 2004);
Myocyte apoptosis (Cardiovasc Res 2004);
Adverse remodeling (Am J Physiol Heart Circ Physiol 2007);
Reduction of the inotropic reserve (NEJM 1982);
Myocardial ROS production (J Cell Mol Med 2007);
Risk of arrythmias (NEJM 1991);
Renin-angiotensin-aldosterone system (Am J Physiol 1992);
Renal and peripheral vascular resistance (JACC 2009);
+
-
β-blockers
The α2A-AR is the main presynaptic inhibitory autoreceptor in the CNS, lowering sympathetic
outflow/BP in response to α2-AR agonist drugs and, along with the α2C-AR, inhibits NE release
in mouse atria (Hein et al., 1999, Nature 402:181–184). α2-ARs are responsible for the
autocrine feedback inhibition of CA release from the adrenal gland (Brede et al., 2003, Mol.
Endocrinol. 17:1640-1646).
α2ARs of cardiac sympathetic nerves and adrenal gland play an essential role in regulation of
SNS activity/outflow in HF (Brede et al., 2002, Circulation 106, 2491-2496, Brum et al., 2002,
Am. J. Physiol. Heart Circ. Physiol. 283, H1838-H1845, Small et al., 2002, N. Engl. J. Med.
347, 1135-1142).
Lymperopoulos A, Rengo G et al Nat. Med. 2007
Adrenal GRK2 upregulation mediates sympathetic overdrive
in heart failure
#
sham
HF
UK14304+Nicotine
*
0
10
20
30
40
50
60
70
Nicotine
Ep
ine
ph
rin
e s
ec
reti
on
(% o
ve
r b
asa
l)
0
10
20
30
40
50
60
70
Nicotine UK14304+NicotineN
ore
pin
ep
hri
ne s
ec
reti
on
(% o
ve
r b
asa
l)
#
**
*, p<0.01 vs. Nicotine-sham, **, p<0.05, vs. Nicotine-sham, #, p<0.05 vs. Nicotine-HF, n=6
Desensitization of α2ARs in HF
rat adrenal-derived chromaffin cells
Lymperopoulos A, Rengo G et al Nat. Med. 2007
-10
0
10
20
30
40
50
60
70
Nicotine UK14304+NicotineNo
rep
inep
hri
ne s
ecre
tio
n
(% o
ver
basal)
HF rat chromaffin cells
-10
0
10
20
30
40
50
Nicotine UK14304+Nicotine
Ep
ine
ph
rin
e s
ec
reti
on
(% o
ve
r b
asa
l)
*
#
*
#
GFP
bARKct
*, p<0.05 vs.
UK14304+Nicotine-
GFP, p<0.01 vs.
Nicotine-bARKct, #,
p<0.05 vs. Nicotine-
GFP, n=9
βARKct restores adrenal α2AR-induced CA secretion
inhibition in HF rats
Lymperopoulos A, Rengo G et al Nat. Med. 2007
Lymperopoulos , Rengo et al. Mol Ther 2008
Adrenal GRK2 upregulation mediates sympathetic
overdrive in heart failure
0
200
400
600
800
1000
1200
AdGFP AdbARKct
Norepinephrine
Epinephrine
Pla
sm
a leve
ls
(pg/m
l)
**
*, p<0.05 vs. AdGFP Lymperopoulos A, Rengo G et al Nat. Med. 2007
*, p<0.05, compared to AdGFP, ^,
p<0.05, compared to AdGFP, **,
p<0.05, compared to AdGRK2
*
*
^,*
*
^,*
*Pla
sm
a l
evels
(pg/m
l)
0
50
100
150
200
250
300
350
400
AdGFP AdGRK2 AdbARKct
Epinephrine
Norepinephrine
Manipulation of adrenal GRK2 levels
modulates plasma CA level in vivo
GRK2
bARKct
actin
AdGFP AdGRK2 AdbARKct
Immunoblotting
in rat adrenals
Lymperopoulos , Rengo et al. Mol Ther 2008
10X
Injection
Negative Control
Gallein Reduced Plasma CAs and adrenal Hypertrophy,
and restores α2-AR feedback inhibition of CA release
Kamal FA et al. JACC 2014.
Cortex
Medulla
Cortex
Medulla
Cortex
Medulla
Ab-TH Ab-GRK2 Blank
20
30
40
50
0
10
-10
60
70
Ep
i s
ec
reti
on
(%
ove
r b
as
al)
*
* #
20
30
40
50
0
10
-10
60
70
-20
-30
NE
pi
se
cre
tio
n (%
ove
r b
as
al)
*
* #
Nicotine
UK + Nicotine
GRK2 regulates adrenal α2-AR-CA production axis
in human chromaffin cells
Rengo G et al. Unpublished data
* *
*, p<0.05, vs. Nicotine; #, p<0.05, vs. UK+Nicotine of other groups
Kamal FA et al. JACC 2014
Gallein reduces CA secretion and normalizes α2-AR feedback
inhibition in pheochromocytoma human adrenal medulla
0
2000
4000
6000
8000
10000
12000
14000
16000
1 2
+dp/dT basal
+dp/dT max
Young OldYoung
0,0000
10,0000
20,0000
30,0000
40,0000
50,0000
60,0000
70,0000
1 2
YoungOldYoung
EF
(%
)
-10000
-9000
-8000
-7000
-6000
-5000
-4000
-3000
-2000
-1000
0
-dp/dT basal
-dp/dT max
Rengo G et al. Unpublished data
*, p<0.05, vs. Young
*
*
Effects of age on cardiac function and inotropic reserve
Age-related alterations of adrenal GRK2-α2-adrenergic receptor-
catecholamine production axis
GRK2
GAPDH
Rengo G et al. Unpublished data
0,00
50,00
100,00
150,00
200,00
250,00
300,00
350,00
400,00
1 2
Epi
NE
YoungOldYoung
Pla
sma
level
s (p
g/m
l)
0,0000
0,5000
1,0000
1,5000
2,0000
2,5000
1 2
GR
K2/G
AP
DH
pro
tein
lev
els
(AU
)
Young OldYoung
0,0000
10,0000
20,0000
30,0000
40,0000
50,0000
60,0000
1 2Young OldYoung
*
*
*
*
*, p<0.05, vs. Young Addre
nal
alf
a2-A
R d
ensi
ty
(fm
ol/
mg o
f m
embra
ne
pro
tein
)
Rengo G et al. Unpublished data
α2-adrenergic receptor responsiveness in adrenal chromaffin cells
extracted from young and old rats
*, p<0.05, vs. Nicotine
0
0,05
0,1
0,15
0,2
0,25
0,3
0,35
0,4
0,45
0,5
1 2
Nic
UK+Nic
0
0,05
0,1
0,15
0,2
0,25
0,3
0,35
0,4
0,45
0,5
1 2
Nic
UK+Nic
Ep
inep
hri
ne
secr
etio
n
(% o
ver
bas
al)
No
repin
eph
rin
e se
cret
ion
(% o
ver
bas
al)
YoungYoung Old Young Old
**
Rengo G et al. Unpublished data
Effects of GRK2 inhibition on α2-adrenergic receptor
responsiveness in adrenal chromaffin cells extracted from old rats
0
0,05
0,1
0,15
0,2
0,25
0,3
0,35
0,4
0,45
1 2
Nic
UK+Nic
0
0,1
0,2
0,3
0,4
0,5
0,6
1 2
Nic
UK+Nic
Epin
eph
rin
e se
cret
ion
(% o
ver
bas
al)
No
repin
eph
rin
e se
cret
ion
(% o
ver
bas
al)
YoungOld-GFP Old-
GRK2ctYoung
Old-GFP Old-
GRK2ct
**
*, p<0.05, vs. Nicotine
CONCLUSIONS
• SNS hyperactivity is a salient characteristic of chronic
HF and of physiological ageing
• Cardiac β-AR dysregulation is strictly related to SNS
overdrive
• Adrenal medulla seems to play a relevant role in the
determination of CA circulating levels
• GRK2-mediated α2-adrenergic receptor dysfunction
is a crucial mechanism of SNS overdrive in HF
• GRK2 regulates CA realease also from human
chromaffin cells
• GRK2 inhibition in chromaffin cells extracted from old
rats resulted in enhanced α2-AR responsiveness and
reduced CA release
Acknowledgements
Dpt. of Translational Medical Sciencies
Federico II University of Naples:
Prof. Nicola Ferrara, MD
Prof. Dario Leosco, MD, PhD
Alessandro Cannavo, MS, PhD
Pina Gambino, MS, PhD student
Klara Komici, MD
Maria Loreta D’Amico, MS, PhD student
Andrea Elia, MS
Roberto Formisano, MD
Laura Petraglia, MD
Grazia Daniela Femminella, MD, PhD
Claudio de Lucia, MD
Daniela Liccardo, MS, PhD
Gennaro Pagano, MD
Center for Translational Medicine, Temple
University, Philadelphia, PA:
Walter J Koch, PhD
Erhe Gao, MD, Joseph E Rabinowitz, PhD
Dept. of Pharmaceutical Sciences, Nova
Southeastern University, Fort Lauderdale,
FL:
Anastasios Lymperopoulos, PhD