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Effect of gliclazide on oxidative stress in the vascular wall Istanbul April 28, 2007 Dr. L....
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Transcript of Effect of gliclazide on oxidative stress in the vascular wall Istanbul April 28, 2007 Dr. L....
Effect of gliclazide on oxidative stress inthe vascular wall
IstanbulApril 28, 2007
Dr. L. Rodríguez MañasSº de Geriatría y U. de InvestigaciónHospital Universitario de Getafe
EARLY STAGES
FINAL STEPS… ¿SHARED?
INVOLVED FACTORS Adrenergic tone Collagen Vascular remodelling Perivascular innervation Reparing mechanisms Neovascularization ……….
ALLA RICERCA DEL MINOTAURO
Physiological role of the vascular endothelium
Furchgott RF, Zawadki JV. The obligatory role of endothelial cells in the relaxation of arterial smooth muscle by acetylcholine. Nature 288:373-376, 1980.
Vascular relaxation induced by acetylcholine is mediated by the action of a factor released by the endothelium (EDRF) that produces a relaxation of the smooth muscle cells.
Characteristics of EDRF
-Released by several vasoactive agents(ACh, BK, 5-HT, thrombin, ADP, etc).
-Very short half-life (seconds).
-Inactivated by Reactive Oxygen Species (ROS, free radicals).
-Mechanism:Estimulation of soluble guanilate cyclaseAnd increase of intracellular cGMP.
L-ArginineL-Arginine L-CitrulineL-Citruline
NONO
NO-synthaseNO-synthase
EndothelialEndothelialCellCell
NO-GMPc
NONO GCsGCs
GTPGTP
PKPK
GMPcGMPc
[Ca[Ca2+2+]]ii
VasodilationVasodilation
SmoothSmoothMuscleMusclecellcell
R-SNOR-SNO
R-SHR-SHNitrosotiolsNitrosotiols
BHBH44
-Furchgott y Louis Ignarro (1986):EDRF may be nitric oxide. -Palmer RMJ, Ferrige AG, Moncada S.Nature 327:524-526, 1987.
Palmer RMJ, Ashton DS, Moncada S.Vascular endothelial cells synthesizenitric oxide from L-arginine.Nature 333: 664-666, 1988.
Oxidative stress and NO
Endothelium
Smooth Muscle Cells
BasalMembrane
BK
NO
eNOS
O2-
GMPcGMPc
OONOOONO••
Superoxide anions
< 60 years > 60 years
Peroxinitrite(nitrotyrosine)
< 60 years > 60 years
NOS
L-arg
NO O2-
BH4
NOS uncoupling
NOS
L-arg
BH4
OONOOONO••
NOO2-
Sources of ROS
I
H+
III
H+
IV
H+
II
H+H+
NAD+ NADH FADH2
FADH2O
O2
ATP sintasa UCP
ADP+Pi ATP
e-
e-Q-
e- e-
cit c
O2 O2-
Generation of free radicals
Brownlee M. Nature 2001; 414: 813-820Brownlee M. Nature 2001; 414: 813-820
HyperglycemiaHyperglycemia
MitochondriaMitochondria
OO22--
PKCPKC
NADPH oxidaseNADPH oxidase eNOSeNOS
OO22--
NONOPeroxinitritePeroxinitrite
NitrotyrosineNitrotyrosine
Endothelial dysfunctionEndothelial dysfunction
Damaged DNADamaged DNAPARPPARP
↑ ↑ poliolspoliols
GlutationGlutation
↑ ↑ DAGDAGAGEAGE
--
DiabetesDiabetes Endothelial
Dysfunction?
HbHb CH CHCH CH
OHOH
NN RR
Schiff Base
Hb-NH 2Hb-NH 2 ++C
C
C
C OHOHH
R
H
R
H OH O
HemoglobinaHemoglobin
GlucosaGlucose
NH RNH RHb CH2 CHb CH2 C
OO
Amadori Adducts
Intermediate Glycosylation
Products
-O2
-O2
-O2
-O2
Release of superoxide anions byRelease of superoxide anions byGlycosylated hemoglobinGlycosylated hemoglobin
EndotheliumEndothelium
ACh
HbHGNONO
HbHGHbHG
O2-eNOS
(+)
O2-
Smooth Smooth MuscleMuscleCellCell
RELAXATIONRELAXATION
L. Rodriguez-Mañas et al., Circulation 1993J. Angulo et al., Hypertension 1996S. Vallejo et al., Diabetologia 2000
DIABETES
THERE IS AN IMPAIRMENT OF THE ENDOTHELIUM-DEPENDENT RESPONSESMEDIATED BY NO
ENDOTHELIUMENDOTHELIUM
ACh
HbHGNONO
HbHGHbHG
O2-eNOS
(+)
O2-SMCSMC
RELAXATIONRELAXATION
-9 -8 -7 -6 -50
20
40
60
80
100
ACh (logM)
*
DIABETIC
CONTROLS
Sodium Nitroprusside
GTPGTP
GMPcGMPcGCGC + NONO
SMOOTH MUSCLESMOOTH MUSCLE
OO22--
OO22--
OO22--
x
Diabetes ImprovementGlycemic control
x
Mch
NOSNOSL-argL-arg
NONO+
LNMMA
-
ENDOTHELIUMENDOTHELIUM
NONO
Rodríguez-Mañas et al.J Hypertension, 2003; 21: 1137-1143
Age (yr) 59.2 ± 1.2 ----SBP (mm Hg) 132.2 ± 3.7 130.0 ± 4.71 NSDBP (mm Hg) 81.0 ± 2.4 76.0 ± 4.06 NSInsulinaemia (µU/mL) 12.5 ± 3.2 9.7 ± 1.35 NSCholesterol (mmol/L) 5.8 ± 0.3 5.6 ± 0.30 NSLDL-Chol. (mmol/L) 3.9 ± 0.3 3.6 ± 0.38 NSHDL-Chol. (mmol/L) 1.3 ± 0.1 1.4 ± 0.09 NSSerum creatinine (µmol/L) 85.1 ± 4.2 87.2 ± 2.89 NSBMI (Kg/m2) 28.3 ± 2.4 ----HbA1c (%)* 9.2 ± 0.5 6.9 ± 0.18 p<0.05AGEs (mcg/mL)* 13.6 ± 1.5 4.9 ± 1.18 p<0.05
PRE-TREAT(mean±SE)
POST-TREAT(mean±SE)
* Mean of the values from the patients that achieved a good metabolic control (HbA1c<7.5%) after treatment with gliclazide during 4 months (n=7). The remaining values are obtained from the whole of the sample (n=10)
18.179.094.540
100
200
300
400
500
600
Pretreatment
Post-treatment
ACh (µgr/min)
% c
han
ge
c/n
c
Type 2 Diabetes
*
0
100
200
300
400
500
600 Pretreatment
Post-treatment
% c
han
ge
c/n
c
Type 2 Diabetes
37.812.64.2
SNP (µmol/min)
*
TREATMENT WITH GLICLAZIDE
IS ACCOMPANIED BY AN
IMPROVEMENT OF THE
ENDOTHELIAL FUNCTION
CONCLUSION
Differential effect of gliclazide and glibenclamide on forearm vascular reactivity
0
3
6
9
0
5
10
15
20
25
30
35
HbA1cHbA1c Post-ischemic Post-ischemic reactive hyperemiareactive hyperemia
(%)
(%)
(ml m
in(m
l min
-1-1/1
00m
l)/1
00m
l)
GlibGlib GliclazideGliclazideGlibGlib GliclazideGliclazide
Pre Post Pre Post Pre Post Pre Post
Wascher TC & Boes U Clin Physiol Funct Imaging. 2005;25:40
Natali A, et al. Vascular Effects of Improving Metabolic Control With Metformin or Rosiglitazone in Type 2 Diabetes. Diabetes Care 2004; 27: 1349.
IS THIS EFFECT DUE TO AN
IMPROVEMENT OF THE METABOLIC
CONTROL (INESPECIFIC) OR TO A
PARTICULAR EFFECT OF GLICLAZIDE?
QUESTION
COURAGE…… WE ARE FINISHING !!!
MicrovesselsExtraction
-8 -7 -60
20
40
60
80
100
Control10 nM 14% GHHb10 µM Ascorbate+GHHb
-8 -7 -6
Control10 nM 14% GHHb
100 U/ml SOD+GHHb
*%
co
ntr
acti
on
BK (log M)
Human mesenteric microvessels
Vallejo S et al., Diabetologia 2000; 43: 83-90.
Human mesenteric microvessels
% c
on
tra
ctio
n
BK (log M)
-8 -7 -60
20
40
60
80
100Control10 nM 14 GHHbGHHb + 0.1 µM Gliclazide
**
Vallejo S et al., Diabetologia 2000; 43: 83-90.
BK (log M)
-8 -7 -60
20
40
60
80
100 Control10 nM 14% GHHbGHHb + 1 µM Gliclazide
** †
% c
on
tra
ctio
n
BK (log M)
Human mesenteric microvessels
-8 -7 -60
20
40
60
80
100Control10 nM 14% GHHbGHHb + 10 µM Gliclazide
*
Vallejo S et al., Diabetologia 2000; 43: 83-90.
BK (log M)
Control10 nM 14% GHHbGHHb + 10 µM Glibenclamide
-8 -7 -60
20
40
60
80
100
**
Endothelium
Smooth muscle
Vascular
Membrane
Basal
BK
NONO
eNOS
O2-
O2-
(+)
O2-
NOx
HGHb
XSODVitamin CGliclazide
CONCLUSION
Vallejo S et al., Diabetologia 2000; 43: 83-90.
THE AUTHORS
Sº de GeriatrSº de Geriatríaía
Unidad de InvestigaciónUnidad de Investigación
Hospital Universitario de GetafeHospital Universitario de Getafe
Leocadio Rodríguez MañasLeocadio Rodríguez Mañas
Pedro López-DórigaPedro López-Dóriga
Susana VallejoSusana Vallejo
Roberto PetidierRoberto Petidier
Julián NevadoJulián Nevado
Mariam Assad de la FuenteMariam Assad de la Fuente
Joaquín Solís JiménezJoaquín Solís Jiménez
Manuel Montes LluchManuel Montes Lluch
Marta Castro RodrMarta Castro Rodríguezíguez
Alberto Sánchez FerrerAlberto Sánchez Ferrer
DepartamentoDepartamento
Farmacología y TerapéuticaFarmacología y Terapéutica
Universidad Autónoma de MadridUniversidad Autónoma de Madrid
Carlos F. Sánchez FerrerCarlos F. Sánchez Ferrer
Concepción PeiróConcepción Peiró
Nuria LafuenteNuria Lafuente
Nuria MatesanzNuria Matesanz
Verónica Azcutia Verónica Azcutia
Elena CercasElena Cercas