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Vitamin C improves endothelial dysfunction in renal allograft recipients
Heart, Lung and Circulation
ELUTION
OF I-IAF’TOGLOBIN HUMAN CORONARY
2000; 9
FROM ATHEROSCLEROTIC ARTERIES IN WV0
M.A. Matuszek*l. P.G. Bannon2. P.N. Hendel2, C.F. Huehes2. W. Jessu 1 R. . -3 The Heart Research Institutel, Cardiothoracic Surgical Unit Royal Prince Alfred Hospita12, and Dept. of Cardiology Concord Hospita13, all in Sydney, NSW, Australia. Molecules which egress from atherosclerotic arteries may function as plasma markers of arterial pathology, but such egress has not been proven with living human coronary arteries. We hypothesised that proteins elute from the arterial wall during coronary perfusion, and that their
quaatitation
in
coronary
perfusate
may
differentiate
between
angiographically extensive and minor coronary atherosclerosis. During cardiac bypass surgery, antegradely flushed coronary cardioplegia solution was collected from the coronary sinus in sequential fractions via a retrograde catheter in 38 subjects with angiographically extensive (n=31) or minor (n=7) coronary disease. The haemoglobin (Hb) content in each petfusate fraction was determined before centrifugation to quantify blood contamination, and the erythrocyte-free supematant then analysed. Perfusate supematants were analysed by SDSPAGE electrophoresis and silver staining, and major proteins sequenced after electrophoretic transfer onto PVDF membranes. Data were calculated per pg Hb to account for blood contamination. In each patient, successive fractions contained decreasing blood contamination,
but
total
protein
per
Hb
increased,
indicating
some
protein derived from the coronary circulation. N-terminal sequencing of a major 40 kDa band detected on SDS-PAGE demonstrated 100% identity with beta chain of haptoglobin (Hpt). Hpt was quantified in perfusates by Western blotting using a monoclonal antibody to Hpt beta, and was increased relative to Hb in less blood-contaminated fractions, confirming
that it was not simply
a blood
A115
48th Annual Scientific Meeting of CSANZ
contaminant.
Importantly.
THE EFFECT OF POSTURAL CHANGE ON VASCULAR PERMEABILITY IN HUMANS. S.A. HOD& and LT. Meredffh. Centre for Heart and Chest Research, Monash University, Clayton, Victoria. The endothelium plays a central role in the control of many vascular functions, including vascular tone, thrombosis and permeability. Vascular responses to endothelial stimuli occur over minutes. We sought to examine the physiological changes in vascular permeability as reflected by plasma colloid osmotic pressure (PCOP) in response to postural changes in health. Venous blood was obtained from the arm of 30 healthy volunteers (14 male: 16 female, age 39+10, mean *SD) without overt vascular disease after 20 minutes lying supine and 5 minutes standing. The plasma samples were analysed using an Osmomat 050 Colloid Osmometer with a 1OkDa molecular weight cut-off membrane and 0.9% saline as the reference solution, PCOP measurements were shown to be reproducible (coefficient of repeatability OAmmHg, coefficient of variation 0.7%). A consistent difference was demonstrated between supine (25.6 + 1.57) and erect (27.7 + 1.95) PCOP (p
in
fractions containing very low blood contamination (O.l-0.9% vol/vol) Hpt was markedly increased in patients with extensive atherosclerosis relative to patients with angiographically minor disease (0.039+0.005 pgHpt/pgHb v 0.009iO.003 pgHpt/pgHb, p
human
arteries.
VlTAMIN C IMPROVES ENDOTHELIAL DYSFUNCTION IN RENAL ALLGGRAFT RECIPIENTS. M .A. Wil s* W. .F. .J Jon? R.J. Walker. Department of Medicine, University of Otago, Dunedin, New Zealand Despite the major advancesin the management of patients with endstagerenal disease,these individuals still have an approximately threefold higher risk of dying from coronary heart disease compared with age-matchedhealthy subjects.Endothelial function is impaired in renal allograft recipients but the effects of antioxidant vitamin therapy on endothelial function in such patients is unknown. Methods: Thirteen renal allograft recipients were recruited to the study. Flow-mediated endothelium-dependent dilation and glyceryltrinitrate-induced endothelium-independent dilation of the brachial artery were assessedbefore and 2 h after oral administration of 2 g vitamin C or placebo in a randomised double blind crossover manner. Results: The 13 subjects had a mean age of 48 & 12 years (range 30 to 64). Blood pressure was 141 f 15 mmHe (svstolic)l87 f 8 mmHe (diastolic) andwas not different by treatmen’tlocation. Body mass y index for the group was 27.7 f 3.3 kg/m* and mean serum creatinine was 126 it 40 umol/I. Plasma vitamin C levels increased from 33.5 f 17.0 nmolil to 98.8 + 60.2 nmolll after treatment (P = 0.0001). Endothelium-dependent dilation improved (1.6 f 2.6% to 4.5 k 2.5%) after Vitamin C but was unchanged after placebo (1.9 f 1.5% to 1.8 f 2.5%, P = 0.003 for vitamin C vs placebo). There was no significant change in endothelium-independent dilation in response to vitamin C. Conclusions: Vitamin C acutely improves flow mediated
endothelium-dependent dilation in renal transplant recipients suggesting increased oxidative stressmay have an important role in the impaired endothelial function in these individuals.
EFFECTS OF NATRIURBTIC PEPTIDES ON ATHBROMA-LIKB LESIONS IN RABBIT CAROTID ARTERIES. MN. Barb+. T.A, Gasoari . G .J. Dustine and R.L. Woods. The Howard Flomy Institute, University of Melbourne, VIC, 3010. Atrial and C-type natriuretic peptides (ANP and CNP) are structumlly related hormones which have antiproliferative effects on cultured vascular smooth muscle cells (&da et UZ,1997). Systemic admlnlstration of ANF and CNF prevent intimal thickening in balloon injured rabbit carotid arteries (Shinomiya er al, 1994). The present study investigated whether local, puiarterial infusion of these hormones, in rabbits (n = 4-7). reduces the development of a neointima, and prevents the associated endothelial dysfunction, induced by placement of a silastic collar around the carotid artery. One collar was infused with equimolar doses (1 and 10 PM) of either ANP or CNP, via an osmotic mini-pump delivering 1 pi/h, whilst the contralateral collar was filled with saline (vehicle). After 7 days,control and collared sections were taken for pharmacological and morphological studies. ANP and CNP, at both concentrations, preserved endotheliumdependent
relaxation.
intimal thickening
at the hi&sr
close prevented
model. 1ocrM ANP 77.20 f 14.8
ratio - IMR)
in this
80.90 f 1.6 0.04
Collar chlly 51.60’ f 6.2 0.17’
1pM ANP 80.70 i 7.2
1 pM CNP 80.40 f 6.8
O.ll
0.1g*
0.18
It 0.01
f 0.01
f 0.09
f 0.01
f 0.01
Control Max. % relaxation lMR
Only CNP, however,
(inti~rnedial
the
low CNP 74.30 * 3.2 0.06
f 0.01
Symbol indicates significant (p&05) effect of collar only (*) or collar + treatment(#) compared to control. Since the natriuratic paptide type B receptor (NF’a) has a much higher
affinity for CNP than ANP, the differences in morphological effects of ANP and CNP, at the 10 pM dose, support the proposal that the NPa receptor mediatesthe antiproliferative actions of CNP. lkeda et d (1997) Artarioscler Thromh Vast Biol, 17.731-736 Shinomiya M er al (1994) Biochem Biophys Res Common, 205,1051-1056
ELUTION
OF I-IAF’TOGLOBIN HUMAN CORONARY
2000; 9
FROM ATHEROSCLEROTIC ARTERIES IN WV0
M.A. Matuszek*l. P.G. Bannon2. P.N. Hendel2, C.F. Huehes2. W. Jessu 1 R. . -3 The Heart Research Institutel, Cardiothoracic Surgical Unit Royal Prince Alfred Hospita12, and Dept. of Cardiology Concord Hospita13, all in Sydney, NSW, Australia. Molecules which egress from atherosclerotic arteries may function as plasma markers of arterial pathology, but such egress has not been proven with living human coronary arteries. We hypothesised that proteins elute from the arterial wall during coronary perfusion, and that their
quaatitation
in
coronary
perfusate
may
differentiate
between
angiographically extensive and minor coronary atherosclerosis. During cardiac bypass surgery, antegradely flushed coronary cardioplegia solution was collected from the coronary sinus in sequential fractions via a retrograde catheter in 38 subjects with angiographically extensive (n=31) or minor (n=7) coronary disease. The haemoglobin (Hb) content in each petfusate fraction was determined before centrifugation to quantify blood contamination, and the erythrocyte-free supematant then analysed. Perfusate supematants were analysed by SDSPAGE electrophoresis and silver staining, and major proteins sequenced after electrophoretic transfer onto PVDF membranes. Data were calculated per pg Hb to account for blood contamination. In each patient, successive fractions contained decreasing blood contamination,
but
total
protein
per
Hb
increased,
indicating
some
protein derived from the coronary circulation. N-terminal sequencing of a major 40 kDa band detected on SDS-PAGE demonstrated 100% identity with beta chain of haptoglobin (Hpt). Hpt was quantified in perfusates by Western blotting using a monoclonal antibody to Hpt beta, and was increased relative to Hb in less blood-contaminated fractions, confirming
that it was not simply
a blood
A115
48th Annual Scientific Meeting of CSANZ
contaminant.
Importantly.
THE EFFECT OF POSTURAL CHANGE ON VASCULAR PERMEABILITY IN HUMANS. S.A. HOD& and LT. Meredffh. Centre for Heart and Chest Research, Monash University, Clayton, Victoria. The endothelium plays a central role in the control of many vascular functions, including vascular tone, thrombosis and permeability. Vascular responses to endothelial stimuli occur over minutes. We sought to examine the physiological changes in vascular permeability as reflected by plasma colloid osmotic pressure (PCOP) in response to postural changes in health. Venous blood was obtained from the arm of 30 healthy volunteers (14 male: 16 female, age 39+10, mean *SD) without overt vascular disease after 20 minutes lying supine and 5 minutes standing. The plasma samples were analysed using an Osmomat 050 Colloid Osmometer with a 1OkDa molecular weight cut-off membrane and 0.9% saline as the reference solution, PCOP measurements were shown to be reproducible (coefficient of repeatability OAmmHg, coefficient of variation 0.7%). A consistent difference was demonstrated between supine (25.6 + 1.57) and erect (27.7 + 1.95) PCOP (p
in
fractions containing very low blood contamination (O.l-0.9% vol/vol) Hpt was markedly increased in patients with extensive atherosclerosis relative to patients with angiographically minor disease (0.039+0.005 pgHpt/pgHb v 0.009iO.003 pgHpt/pgHb, p
human
arteries.
VlTAMIN C IMPROVES ENDOTHELIAL DYSFUNCTION IN RENAL ALLGGRAFT RECIPIENTS. M .A. Wil s* W. .F. .J Jon? R.J. Walker. Department of Medicine, University of Otago, Dunedin, New Zealand Despite the major advancesin the management of patients with endstagerenal disease,these individuals still have an approximately threefold higher risk of dying from coronary heart disease compared with age-matchedhealthy subjects.Endothelial function is impaired in renal allograft recipients but the effects of antioxidant vitamin therapy on endothelial function in such patients is unknown. Methods: Thirteen renal allograft recipients were recruited to the study. Flow-mediated endothelium-dependent dilation and glyceryltrinitrate-induced endothelium-independent dilation of the brachial artery were assessedbefore and 2 h after oral administration of 2 g vitamin C or placebo in a randomised double blind crossover manner. Results: The 13 subjects had a mean age of 48 & 12 years (range 30 to 64). Blood pressure was 141 f 15 mmHe (svstolic)l87 f 8 mmHe (diastolic) andwas not different by treatmen’tlocation. Body mass y index for the group was 27.7 f 3.3 kg/m* and mean serum creatinine was 126 it 40 umol/I. Plasma vitamin C levels increased from 33.5 f 17.0 nmolil to 98.8 + 60.2 nmolll after treatment (P = 0.0001). Endothelium-dependent dilation improved (1.6 f 2.6% to 4.5 k 2.5%) after Vitamin C but was unchanged after placebo (1.9 f 1.5% to 1.8 f 2.5%, P = 0.003 for vitamin C vs placebo). There was no significant change in endothelium-independent dilation in response to vitamin C. Conclusions: Vitamin C acutely improves flow mediated
endothelium-dependent dilation in renal transplant recipients suggesting increased oxidative stressmay have an important role in the impaired endothelial function in these individuals.
EFFECTS OF NATRIURBTIC PEPTIDES ON ATHBROMA-LIKB LESIONS IN RABBIT CAROTID ARTERIES. MN. Barb+. T.A, Gasoari . G .J. Dustine and R.L. Woods. The Howard Flomy Institute, University of Melbourne, VIC, 3010. Atrial and C-type natriuretic peptides (ANP and CNP) are structumlly related hormones which have antiproliferative effects on cultured vascular smooth muscle cells (&da et UZ,1997). Systemic admlnlstration of ANF and CNF prevent intimal thickening in balloon injured rabbit carotid arteries (Shinomiya er al, 1994). The present study investigated whether local, puiarterial infusion of these hormones, in rabbits (n = 4-7). reduces the development of a neointima, and prevents the associated endothelial dysfunction, induced by placement of a silastic collar around the carotid artery. One collar was infused with equimolar doses (1 and 10 PM) of either ANP or CNP, via an osmotic mini-pump delivering 1 pi/h, whilst the contralateral collar was filled with saline (vehicle). After 7 days,control and collared sections were taken for pharmacological and morphological studies. ANP and CNP, at both concentrations, preserved endotheliumdependent
relaxation.
intimal thickening
at the hi&sr
close prevented
model. 1ocrM ANP 77.20 f 14.8
ratio - IMR)
in this
80.90 f 1.6 0.04
Collar chlly 51.60’ f 6.2 0.17’
1pM ANP 80.70 i 7.2
1 pM CNP 80.40 f 6.8
O.ll
0.1g*
0.18
It 0.01
f 0.01
f 0.09
f 0.01
f 0.01
Control Max. % relaxation lMR
Only CNP, however,
(inti~rnedial
the
low CNP 74.30 * 3.2 0.06
f 0.01
Symbol indicates significant (p&05) effect of collar only (*) or collar + treatment(#) compared to control. Since the natriuratic paptide type B receptor (NF’a) has a much higher
affinity for CNP than ANP, the differences in morphological effects of ANP and CNP, at the 10 pM dose, support the proposal that the NPa receptor mediatesthe antiproliferative actions of CNP. lkeda et d (1997) Artarioscler Thromh Vast Biol, 17.731-736 Shinomiya M er al (1994) Biochem Biophys Res Common, 205,1051-1056