Abstract

Endothelial cells are strategically located between the circulating blood and the vascular smooth muscle. Through release of numerous vasoactive substances, they are crucially involved in regulating the functions of vascular smooth muscle and circulating blood cells. Important endothelium-delivered vasodilators include prostacyclin, bradykinin, endothelium-derived hyperpolarising factor, and nitric oxide. Nitric oxide inhibits cellular growth and migration, and acts in concert with prostacyclin to exert potent antiatherogenic and antithrombotic effects. These effects are counterbalanced by endothelial vasoconstrictors, such as reactive oxygen species, endothelin-1, and angiotensin II, which exert pro-thrombotic, inflammatory, and growth-promoting properties. Cardiovascular risk factors cause cardiovascular disease by causing endothelial dysfunction; thus, modern therapeutic strategies focus on preserving or restoring endothelial integrity. In addition to their role in inhibiting the renin-angiotensin system, angiotensin-converting enzyme (ACE) inhibitors prolong the half-life of bradykinin and stabilize the bradykinin receptor linked to formation of nitric oxide. Chronic ACE inhibition improves endothelial function in patients with cardiovascular risk. This may explain why patients treated with ACE inhibitors experience a greater cardiovascular benefit than is attributable to the decrease in blood pressure. Whether and to what degree improvement of endothelial dysfunction translates into clinical benefits for patients with cardiovascular disease remains to be determined.

References

[1]

Lüscher
TF
, Vanhoutte PM. The Endothelium: Modulator of Cardiovascular Function. Boca Raton, Fla: CRC Press; 1990. p. 1–215

[2]

Yanagisawa
M
, Kurihara H, Kimura S, et al. A novel potent vasoconstrictor peptide produced by vascular endothelial cells.
Nature
.
1988
;
332
:
411
–415

[3]

Furchgott
RF
, Zawadzki JV. The obligatory role of endothelial cells in the relaxation of arterial smooth muscle by acetylcholine.
Nature
.
1980
;
288
:
373
–376

[4]

Zeiher
AM
, Drexler H, Saurbier B, Just H. Endothelium-mediated coronary blood flow modulation in humans. Effects of age, atherosclerosis, hypercholesterolemia, and hypertension.
J Clin Invest
.
1993
;
92
:
652
–662

[5]

Johnstone
MT
, Creager SJ, Scales KM, Cusco JA, Lee BK, Creager MA. Impaired endothelium-dependent vasodilation in patients with insulin- dependent diabetes mellitus. [see comments]
Circulation
.
1993
;
88
:
2510
–2516

[6]

Zeiher
AM
, Schächinger V, Minners J. Long-term cigarette smoking impairs endothelium-dependent coronary arterial vasodilator function.
Circulation
.
1995
;
92
:
1094
–1100

[7]

Chowienczyk
PJ
, Watts GF, Cockcroft JR, Ritter JM. Impaired endothelium-dependent vasodilation of forearm resistance vessels in hypercholesterolaemia. [see comments]
Lancet
.
1992
;
340
:
1430
–1432

[8]

Drexler
H
, Zeiher AM, Meinzer K, Just H. Correction of endothelial dysfunction in coronary microcirculation of hypercholesterolaemic patients by L-arginine.
Lancet
.
1991
;
338
:
1546
–1550

[9]

Creager
MA
, Gallagher SJ, Girerd XJ, Coleman SM, Dzau VJ, Cooke JP. L-arginine improves endothelium-dependent vasodilation in hypercholesterolemic humans.
J Clin Invest
.
1992
;
90
:
1248
–1253

[10]

Taddei
S
, Virdis A, Mattei P, et al. Aging and endothelial function in normotensive subjects and patients with essential hypertension.
Circulation
.
1995
;
91
:
1981
–1987

[11]

Taddei
S
, Virdis A, Ghiadoni L, et al. Menopause is associated with endothelial dysfunction in women.
Hypertension
.
1996
;
28
:
576
–582

[12]

Taddei
S
, Virdis A, Mattei P, Salvetti A. Vasodilation to acetylcholine in primary and secondary forms of human hypertension.
Hypertension
.
1993
;
21
:
929
–933

[13]

Taddei
S
, Virdis A, Mattei P, et al. Hypertension causes premature aging of endothelial function in humans.
Hypertension
.
1997
;
29
:
736
–743

[14]

Vallance
P
, Calver A, Collier J. The vascular endothelium in diabetes and hypertension.
J Hypertens Suppl
.
1992
;
10
:
S25
–S29

[15]

Schächinger
V
, Britten MB, Zeiher AM. Prognostic impact of coronary vasodilator dysfunction on adverse long-term outcome of coronary heart disease.
Circulation
.
2000
;
101
:
1899
–1906

[16]

Rees
DD
, Palmer RM, Moncada S. Role of endothelium-derived nitric oxide in the regulation of blood pressure. Proc Natl Acad Sci USA. 1989. p. 3375–3378

[17]

Blot
S
, Arnal JF, Xu Y, Gray F, Michel JB. Spinal cord infarcts during long-term inhibition of nitric oxide synthase in rats.
Stroke
.
1994
;
25
:
1666
–1673

[18]

Palmer
RM
, Bridge L, Foxwell NA, Moncada S. The role of nitric oxide in endothelial cell damage and its inhibition by glucocorticoids.
Br J Pharmacol
.
1992
;
105
:
11
–12

[19]

Linz
W
, Wiemer G, Gohlke P, Unger T, Schölkens BA. Contribution of kinins to the cardiovascular actions of angiotensin-converting enzyme inhibitors.
Pharmacol Rev
.
1995
;
47
:
25
–49

[20]

Cushman
DW
, Cheung HS. Concentrations of angiotensin-converting enzyme in tissues of the rat.
Biochim Biophys Acta
.
1971
;
250
:
261
–265

[21]

Palmer
RM
, Ferrige AG, Moncada S. Nitric oxide release accounts for the biological activity of endothelium-derived relaxing factor.
Nature
.
1987
;
327
:
524
–526

[22]

Mombouli
JV
, Illiano S, Nagao T, Scott-Burden T, Vanhoutte PM. Potentiation of endothelium-dependent relaxations to bradykinin by angiotensin I converting enzyme inhibitors in canine coronary artery involves both endothelium-derived relaxing and hyperpolarizing factors.
Circ Res
.
1992
;
71
:
137
–144

[23]

Todd
PA
, Benfield P. Ramipril. A review of its pharmacological properties and therapeutic efficacy in cardiovascular disorders.
Drugs
.
1990
;
39
:
110
–135

[24]

Dendorfer
A
, Reibetamann S, Wolfrum S, Raasch W, Dominiak P. Potentiation of kinin analogues by ramiprilat is exclusively related to their degradation.
Hypertension
.
2001
;
38
:
142
–146

[25]

Benzing
T
, Fleming I, Blaukat A, Muller-Esterl W, Busse R. Angiotensin-converting enzyme inhibitor ramiprilat interferes with the sequestration of the B2 kinin receptor within the plasma membrane of native endothelial cells.
Circulation
.
1999
;
99
:
2034
–2040

[26]

Hornig
B
, Landmesser U, Kohler C, et al. Comparative effect of ACE inhibition and angiotensin II type 1 receptor antagonism on biovailability of nitric oxide in patients with coronary artery disease: role of superoxide dismutase.
Circulation
.
2001
;
103
:
799
–805

[27]

Jin
ZQ
, Chen X. Pretreatment with ramiprilat induces cardioprotection against free radical injury in guinea-pig isolated heart: involvement of bradykinin, protein kinase C and prostaglandins.
Clin Exp Pharmacol Physiol
.
2000
;
27
:
257
–262

[28]

Jin
ZQ
, Chen X. Ramipril-induced delayed myocardial protection against free radical injury involves bradykinin B2 receptor-NO pathway and protein synthesis.
Br J Pharmacol
.
1998
;
125
:
556
–562

[29]

Linz
W
, Wiemer G, Schölkens BA. ACE-inhibition induces NO-formation in cultured bovine endothelial cells and protects isolated ischemic rat hearts.
J Mol Cell Cardiol
.
1992
;
24
:
909
–919

[30]

Berkenboom
G
, Fontaine D, Unger P, Baldassarre S, Preumont N, Fontaine J. Absence of nitrate tolerance after long-term treatment with ramipril: an endothelium-dependent mechanism.
J Cardiovasc Pharmacol
.
1999
;
34
:
547
–553

[31]

Berkenboom
G
, Langer I, Carpentier Y, Grosfils K, Fontaine J. Ramipril prevents endothelial dysfunction induced by oxidized low-density lipoproteins: a bradykinin-dependent mechanism.
Hypertension
.
1997
;
30
:
371
–376

[32]

Berkenboom
G
. Bradykinin and the therapeutic actions of angiotensin-converting enzyme inhibitors.
Am J Cardiol
.
1998
;
82
:
11S
–13S

[33]

Keidar
S
, Attias J, Coleman R, Wirth K, Scholkens B, Hayek T. Attenuation of atherosclerosis in apolipoprotein E-deficient mice by ramipril is dissociated from its antihypertensive effect and from potentiation of bradykinin.
J Cardiovasc Pharmacol
.
2000
;
35
:
64
–72

[34]

Kramer
CM
, Ferrari VA, Rogers WJ, et al. Angiotensin-converting enzyme inhibition limits dysfunction in adjacent noninfarcted regions during left ventricular remodeling.
J Am Coll Cardiol
.
1996
;
27
:
211
–217

[35]

Nguyen
T
, El Salibi E, Rouleau JL. Postinfarction survival and inducibility of ventricular arrhythmias in the spontaneously hypertensive rat: effects of ramipril and hydralazine.
Circulation
.
1998
;
98
:
2074
–2080

[36]

Linz
W
, Wohlfart P, Schölkens BA, Becker RH, Malinski T, Wiemer G. Late treatment with ramipril increases survival in old spontaneously hypertensive rats.
Hypertension
.
1999
;
34
:
291
–295

[37]

Linz
W
, Jessen T, Becker RH, Schölkens BA, Wiemer G. Long-term ACE inhibition doubles lifespan of hypertensive rats.
Circulation
.
1997
;
96
:
3164
–3172

[38]

Lüscher
TF
, Vanhoutte PM, Raij L. Antihypertensive treatment normalizes decreased endothelium-dependent relaxations in rats with salt-induced hypertension.
Hypertension
.
1987
;
9
:
III193
–III197

[39]

Tschudi
MR
, Criscione L, Novosel D, Pfeiffer K, Lüscher TF. Antihypertensive therapy augments endothelium-dependent relaxations in coronary arteries of spontaneously hypertensive rats.
Circulation
.
1994
;
89
:
2212
–2218

[40]

Higashi
Y
, Sasaki S, Nakagawa K, et al. A comparison of angiotensin-converting enzyme inhibitors, calcium antagonists, beta-blockers and diuretic agents on reactive hyperemia in patients with essential hypertension: a multicenter study.
J Am Coll Cardiol
.
2000
;
35
:
284
–291

[41]

Lafleche
A
, Gautier S, Topouchian J, et al. Differential responses of the heart and vasculature to chronic blood pressure reduction in essential hypertension.
Clin Pharmacol Ther
.
1998
;
64
:
96
–105

[42]

Cacciapuoti
F
, Capasso A, Mirra G, De Nicola A, Minicucci F, Gentile S. Prevention of left ventricular hypertrophy by ACE-inhibitor, ramipril in comparison with calcium-channel antagonist, felodipine.
Int J Cardiol
.
1998
;
63
:
175
–178

[43]

Kahan
T
, Eliasson K. The influence of long-term ACE inhibitor treatment on circulatory responses to stress in human hypertension.
Am J Hypertens
.
1999
;
12
:
1188
–1194

[44]

Mancini
GB
, Henry GC, Macaya C, et al. Angiotensin-converting enzyme inhibition with quinapril improves endothelial vasomotor dysfunction in patients with coronary artery disease. The TREND (Trial on Reversing ENdothelial Dysfunction) Study.
Circulation
.
1996
;
94
:
258
–265

[45]

Anderson
TJ
, Elstein E, Haber H, Charbonneau F. Comparative study of ACE-inhibition, angiotensin II antagonism, and calcium channel blockade on flow-mediated vasodilation in patients with coronary disease (BANFF study).
J Am Coll Cardiol
.
2000
;
35
:
60
–66

[46]

Kongstad-Rasmussen
O
, Blomstrand P, Broqvist M, Dahlstrom U, Wranne B. Treatment with ramipril improves systolic function even in patients with mild systolic dysfunction and symptoms of heart failure after acute myocardial infarction.
Clin Cardiol
.
1998
;
21
:
807
–811

[47]

Willenheimer
R
, Rydberg E, Oberg L, Juul-Moller S, Erhardt L. ACE inhibition with ramipril improves left ventricular function at rest and post exercise in patients with stable ischaemic heart disease and preserved left ventricular systolic function.
Eur Heart J
.
1999
;
20
:
1647
–1656

[48]

The Heart Outcomes Prevention Evaluation Study Investigators. Effects of an angiotensin-converting-enzyme inhibitor, ramipril, on cardiovascular events in high-risk patients.

N Engl J Med
.
2000
;
342
:
145
–153

[49]

Cleland
JG
, Erhardt L, Murray G, Hall AS, Ball SG. Effect of ramipril on morbidity and mode of death among survivors of acute myocardial infarction with clinical evidence of heart failure. A report from the AIRE Study Investigators.
Eur Heart J
.
1997
;
18
:
41
–51

[50]

Hall
AS
, Murray GD, Ball SG. Follow-up study of patients randomly allocated ramipril or placebo for heart failure after acute myocardial infarction: AIRE Extension (AIREX) Study. Acute Infarction Ramipril Efficacy.
Lancet
.
1997
;
349
:
1493
–1497

[51]

Hornig
B
, Arakawa N, Haussmann D, Drexler H. Differential effects of quinaprilat and enalaprilat on endothelial function of conduit arteries in patients with chronic heart failure.
Circulation
.
1998
;
98
:
2842
–2848

[52]

O'Driscoll
G
, Green D, Maiorana A, Stanton K, Colreavy F, Taylor R. Improvement in endothelial function by angiotensin-converting enzyme inhibition in non-insulin-dependent diabetes mellitus.
J Am Coll Cardiol
.
1999
;
33
:
1506
–1511

[53]

O'Hare
P
, Bilbous R, Mitchell T, O'Callaghan CJ, Viberti GC. Low-dose ramipril reduces microalbuminuria in type 1 diabetic patients without hypertension: results of a randomized controlled trial.
Diabetes Care
.
2000
;
23
:
1823
–1829

[54]

Dagenais
GR
, Yusuf S, Bourassa MG, et al. Effects of ramipril on coronary events in high-risk persons: results of the Heart Outcomes Prevention Evaluation Study.
Circulation
.
2001
;
104
:
522
–526

[55]

Lee
AF
, Dick JB, Bonnar CE, Struthers AD. Lisinopril improves arterial function in hyperlipidaemia.
Clin Sci
.
1999
;
96
:
441
–448

This content is only available as a PDF.