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Zhang H, Dong J, Lau CW, Huang Y. Berberine Reverses Nitroglycerin Tolerance through Suppressing Protein Kinase C Alpha Activity in Vascular Smooth Muscle Cells. Cardiovasc Drugs Ther 2021; 36:633-643. [PMID: 34319490 DOI: 10.1007/s10557-021-07193-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 04/14/2021] [Indexed: 11/26/2022]
Abstract
PURPOSE The aim of this study was to evaluate the effects of berberine on nitroglycerin (NTG) tolerance and explore the underlying mechanism involved. METHODS NTG tolerance was induced by pre-exposure of Sprague-Dawley rat aortas to NTG in vitro or by pretreating Sprague-Dawley rats with an NTG patch in vivo. The aortas were pre-treated with berberine or PKC inhibitors for different durations of time before induction of NTG tolerance. NTG-induced vasorelaxations was measured on wire myograph. Primary vascular smooth cells (VSMCs) were used to dissect the underlying mechanism of berberine-induced inhibition of NTG tolerance. RESULTS NTG tolerance induced by either prior exposure of rat aortas to NTG in vitro or pretreatment with an NTG patch in vivo was reversed by co-treatment with berberine, as well as the inhibitors of protein kinase C (PKC) and protein kinase C alpha (PKCα). The mechanistic study revealed that PKCα participated in the development of NTG tolerance as NTG increased the activity of PKCα with enriched PKCα membrane localization and elevated phosphorylation of PKCα in VSMCs, which was reversed by berberine or PKCα inhibitors. CONCLUSION This study is probably the first demonstration that berberine reverses NTG tolerance through inhibiting PKCα activity in VSMCs and PKCα is an important contributor to the development of NTG tolerance. These new findings suggest that berberine could become a promising drug for prevention of NTG tolerance and that targeting PKCα in VSMCs is likely to be a potential therapeutic strategy for reversal of NTG tolerance in blood vessels.
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Affiliation(s)
- Huina Zhang
- Beijing An Zhen Hospital, Capital Medical University; Key Laboratory of Upper Airway Dysfunction-related Cardiovascular Diseases, Beijing Institute of Heart Lung and Blood Vessel Disease, Beijing, 100029, China.
| | - Jinghui Dong
- Department of Physiology, Hebei Medical University, Hebei, 050017, China
| | - Chi-Wai Lau
- Shenzhen Research Institute, Heart and Vascular Institute, and Li Ka Shing Institute of Health Sciences, Chinese University of Hong Kong, Hong Kong, 999077, China
| | - Yu Huang
- Shenzhen Research Institute, Heart and Vascular Institute, and Li Ka Shing Institute of Health Sciences, Chinese University of Hong Kong, Hong Kong, 999077, China.
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Zamani P, Akers S, Soto-Calderon H, Beraun M, Koppula MR, Varakantam S, Rawat D, Shiva-Kumar P, Haines PG, Chittams J, Townsend RR, Witschey WR, Segers P, Chirinos JA. Isosorbide Dinitrate, With or Without Hydralazine, Does Not Reduce Wave Reflections, Left Ventricular Hypertrophy, or Myocardial Fibrosis in Patients With Heart Failure With Preserved Ejection Fraction. J Am Heart Assoc 2017; 6:JAHA.116.004262. [PMID: 28219917 PMCID: PMC5523746 DOI: 10.1161/jaha.116.004262] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Background Wave reflections, which are increased in patients with heart failure with preserved ejection fraction, impair diastolic function and promote pathologic myocardial remodeling. Organic nitrates reduce wave reflections acutely, but whether this is sustained chronically or affected by hydralazine coadministration is unknown. Methods and Results We randomized 44 patients with heart failure with preserved ejection fraction in a double‐blinded fashion to isosorbide dinitrate (ISDN; n=13), ISDN+hydralazine (ISDN+hydral; n=15), or placebo (n=16) for 6 months. The primary end point was the change in reflection magnitude (RM; assessed with arterial tonometry and Doppler echocardiography). Secondary end points included change in left ventricular mass and fibrosis, measured with cardiac magnetic resonance imaging, and the 6‐minute walk distance. ISDN reduced aortic characteristic impedance (mean baseline=0.15 [95% CI, 0.14–0.17], 3 months=0.11 [95% CI, 0.10–0.13], 6 months=0.10 [95% CI, 0.08–0.12] mm Hg/mL per second; P=0.003) and forward wave amplitude (Pf, mean baseline=54.8 [95% CI, 47.6–62.0], 3 months=42.2 [95% CI, 33.2–51.3]; 6 months=37.0 [95% CI, 27.2–46.8] mm Hg, P=0.04), but had no effect on RM (P=0.64), left ventricular mass (P=0.33), or fibrosis (P=0.63). ISDN+hydral increased RM (mean baseline=0.39 [95% CI, 0.35–0.43]; 3 months=0.31 [95% CI, 0.25–0.36]; 6 months=0.44 [95% CI, 0.37–0.51], P=0.03), reduced 6‐minute walk distance (mean baseline=343.3 [95% CI, 319.2–367.4]; 6 months=277.0 [95% CI, 242.7–311.4] meters, P=0.022), and increased native myocardial T1 (mean baseline=1016.2 [95% CI, 1002.7–1029.7]; 6 months=1054.5 [95% CI, 1036.5–1072.3], P=0.021). A high proportion of patients experienced adverse events with active therapy (ISDN=61.5%, ISDN+hydral=60.0%; placebo=12.5%; P=0.007). Conclusions ISDN, with or without hydralazine, does not exert beneficial effects on RM, left ventricular remodeling, or submaximal exercise and is poorly tolerated. ISDN+hydral appears to have deleterious effects on RM, myocardial remodeling, and submaximal exercise. Our findings do not support the routine use of these vasodilators in patients with heart failure with preserved ejection fraction. Clinical Trial Registration URL: www.clinicaltrials.gov. Unique identifier: NCT01516346.
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Affiliation(s)
- Payman Zamani
- Division of Cardiovascular Medicine, Hospital of the University of Pennsylvania, Philadelphia, PA
| | - Scott Akers
- Department of Radiology, Philadelphia Veterans' Affairs Medical Center, Philadelphia, PA
| | - Haideliza Soto-Calderon
- Division of Cardiovascular Medicine, Hospital of the University of Pennsylvania, Philadelphia, PA
| | - Melissa Beraun
- Division of Cardiovascular Medicine, Hospital of the University of Pennsylvania, Philadelphia, PA
| | - Maheswara R Koppula
- Division of Cardiovascular Medicine, Hospital of the University of Pennsylvania, Philadelphia, PA
| | - Swapna Varakantam
- Division of Cardiovascular Medicine, Hospital of the University of Pennsylvania, Philadelphia, PA
| | - Deepa Rawat
- Division of Cardiovascular Medicine, Hospital of the University of Pennsylvania, Philadelphia, PA
| | - Prithvi Shiva-Kumar
- Division of Cardiovascular Medicine, Hospital of the University of Pennsylvania, Philadelphia, PA
| | - Philip G Haines
- Division of Cardiovascular Medicine, Hospital of the University of Pennsylvania, Philadelphia, PA.,Rhode Island Hospital, Warren Alpert Medical School of Brown University, Providence, RI
| | - Jesse Chittams
- Office of Nursing Research, School of Nursing, University of Pennsylvania, Philadelphia, PA
| | - Raymond R Townsend
- Division of Nephrology/Hypertension, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Walter R Witschey
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Patrick Segers
- Biofluid, Tissue, and Solid Mechanics for Medical Applications, IBiTech, iMinds Medical IT, Ghent University, Ghent, Belgium
| | - Julio A Chirinos
- Division of Cardiovascular Medicine, Hospital of the University of Pennsylvania, Philadelphia, PA
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3
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Zuj KA, Edgell H, Shoemaker JK, Custaud MA, Arbeille P, Hughson RL. WISE 2005: responses of women to sublingual nitroglycerin before and after 56 days of 6° head-down bed rest. J Appl Physiol (1985) 2012; 113:434-41. [PMID: 22653986 DOI: 10.1152/japplphysiol.00445.2012] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
This study tested the hypothesis that cardiovascular effects of sublingual nitroglycerin (NG) would be exaggerated after 56 days of 6° head-down bed rest (HDBR) in women, and that an aerobic and resistive exercise countermeasure (EX, n = 8) would reduce the effect compared with HDBR without exercise (CON, n = 7). Middle cerebral artery maximal blood flow velocity (CBFV), cardiac stroke volume (SV), and superficial femoral artery blood flow (Doppler ultrasound) were recorded at baseline rest and for 5 min following 0.3 mg sublingual NG. Post-HDBR, NG caused greater increases in heart rate (HR) in CON compared with EX (+24.9 ± 7.7 and +18.8 ± 6.6 beats/min, respectively, P < 0.0001). The increase in HR combined with reductions in SV to maintain cardiac output. Systolic, mean, and pulse pressures were reduced 5-10 mmHg by NG, but total peripheral resistance was only slightly reduced at 3 min after NG. Reductions in CBFV of -12.5 ± 3.8 cm/s were seen after NG, but a reduction in the Doppler resistance index suggested dilation of the middle cerebral artery with no differences after HDBR. The femoral artery dilated with NG and blood flow was reduced ∼50% with the appearance of large negative waves suggesting a marked increase in downstream resistance, but there were no effects of HDBR. In general, responses of women to NG were not altered by HDBR; the greater increase in HR in CON but not EX was probably a consequence of cardiovascular deconditioning. These results contrast with the hypothesis and a previous investigation of men after HDBR by revealing no change in cardiovascular responses to exogenous nitric oxide.
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Affiliation(s)
- K A Zuj
- Faculty of Applied Health Sciences, University of Waterloo, Waterloo, Ontario, Canada
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5
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Wimalawansa SJ. Nitric oxide: new evidence for novel therapeutic indications. Expert Opin Pharmacother 2008; 9:1935-54. [PMID: 18627331 DOI: 10.1517/14656566.9.11.1935] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
BACKGROUND Nitric oxide (NO) deficiency is implicated in many pathophysiological processes in mammals. NO is a ubiquitous molecule involved in multiple cellular functions. Uncontrolled or inappropriate production of NO may lead to several disease states including septic shock, rheumatoid and inflammatory arthropathies, and expansion of cerebral damage after stroke. However, to date, there are no therapeutic agents available that can overcome these conditions. Similarly, underproduction of NO by NO synthase or enhanced breakdown of NO also leads to diseases such as hypertension, ischemic conditions, pre-eclampsia, premature delivery, among others. NO donor therapies are indicated in these conditions. RESULTS Nitroglycerin and nitrates (NO donors) have been used as therapeutic agents for the past century, particularly to treat vascular disease, and the only significant adverse effects are headaches. NO donors are highly cost-effective and have beneficial effects in multiple body systems. When the body cannot generate NO via NO synthase or due to rapid turnover leading to inadequate amounts of NO available for biological homeostasis, administration of exogenous NO, or prolongation of the actions of endogenous NO, are practical ways to supplement NO. CONCLUSION Recipients of such therapy include patients with angina pectoris, coronary artery disease, hypertension, osteoporosis, gastrointestinal motility disorders, pregnancy-related disorders including premature delivery, pre-eclampsia, vulvodynia, and erectile dysfunction in men. Postmenopausal NO deficiency is rectified with hormone replacement therapy, which enhances local production of NO. Declining local NO production secondary to estrogen deficiency in postmenopausal women and perhaps in older men could be one of the reasons for age-related increased incidences of cardiovascular events and sexual dysfunction. Thus, in addition to supplementation of NO compounds in acute situations like alleviating angina and erectile dysfunction, chronic NO therapy is cost-effective in decreasing cardiovascular events, and improving the urogenital system and skeletal health.
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Affiliation(s)
- Sunil J Wimalawansa
- Robert Wood Johnson Medical School, Department of Medicine, New Brunswick, NJ 08903, USA.
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von der Weid PY, Coleman HA. Reduced vascular reactivity after chronic nitroglycerine administration: EDHF mechanism is also downregulated. Br J Pharmacol 2006; 146:479-80. [PMID: 16056231 PMCID: PMC1751182 DOI: 10.1038/sj.bjp.0706364] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Affiliation(s)
- Pierre-Yves von der Weid
- Mucosal Inflammation and Smooth Muscle Research Groups, Department of Physiology & Biophysics, Faculty of Medicine, University of Calgary, Calgary, Alberta, Canada.
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Tousoulis D, Charakida M, Stefanadis C. Inflammation and endothelial dysfunction as therapeutic targets in patients with heart failure. Int J Cardiol 2005; 100:347-53. [PMID: 15837076 DOI: 10.1016/j.ijcard.2004.05.030] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/18/2003] [Revised: 03/16/2004] [Accepted: 05/05/2004] [Indexed: 01/09/2023]
Abstract
Evidence suggests that vascular endothelium plays key role in the regulation of vascular tone, in the process of inflammation and in the thrombotic mechanisms. Recent studies indicate that it is an important component of the pathophysiological mechanisms of heart failure. Heart failure may induce endothelial dysfunction by different mechanisms, such as reduced synthesis and release of nitric oxide (NO), increased degradation of NO or by increased production of endothelin-1. In addition, endothelial dysfunction has been associated with the progression of heart failure. Alterations in neurotransmitters, hormones and also in physiological stimuli are present in heart failure and affect the vascular endothelium. Treatments with beneficial effects on endothelial dysfunction may also improve prognosis in patients with heart failure.
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Affiliation(s)
- Dimitris Tousoulis
- Cardiology Unit, Hippokration Hospital, Athens University Medical School, S. Karagiorga Street 69, 166 75 Glifada Athens, Greece.
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Zhang J, Chen Z, Cobb FR, Stamler JS. Role of mitochondrial aldehyde dehydrogenase in nitroglycerin-induced vasodilation of coronary and systemic vessels: an intact canine model. Circulation 2004; 110:750-5. [PMID: 15289380 DOI: 10.1161/01.cir.0000138105.17864.6b] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND It has recently been shown that mitochondrial aldehyde dehydrogenase 2 (mtALDH) catalyzes the formation of 1,2-glyceryl dinitrate and nitrite from nitroglycerin (glyceryl trinitrate [GTN]) within mitochondria, leading to production of cGMP and vasorelaxation. However, whether this mechanism operates in the systemic and coronary beds that subserve the antianginal action of GTN is not known. In this study, we address this question in an intact canine model. METHODS AND RESULTS Fourteen healthy mongrel dogs (weight, 20 to 25 kg) were studied. Coronary blood flow and hemodynamics were continuously monitored by a pulse Doppler flow probe implanted around the left circumflex coronary artery and with catheters in left ventricle and aorta, respectively. Each dog was given a 1-mL bolus injection of GTN, sodium nitroprusside (SNP), or adenosine through a catheter in the left atrium before and 30 minutes after infusion of cyanamide (17 mg/kg), an inhibitor of mtALDH. Cyanamide significantly inhibited both the classic dehydrogenase and GTN reductase activities of mtALDH in situ and attenuated the coronary blood flow increase and declines in blood pressure and left ventricular end-diastolic pressure produced by GTN in vivo. In contrast, mtALDH inhibition had no effect on the coronary and systemic effects of SNP and adenosine. CONCLUSIONS Our data suggest that mtALDH contributes to GTN biotransformation in vivo and thus at least partly underlies the antianginal mechanism of drug action. Our findings also highlight the differences in biometabolism of clinically relevant nitrosovasodilators.
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Affiliation(s)
- Jian Zhang
- Department of Medicine, Duke University Medical Center, Durham, NC 27710, USA
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Abstract
Organic nitrates such as nitroglycerin (NTG) have been used as potent vasodilators in medicine for more than a century, but their biochemical mechanisms of action, particularly in relation to tolerance development, are still incompletely defined. Numerous candidate enzymes for NTG metabolism, as well as a multiplicity of tolerance mechanisms, have been proposed in the literature, but a consolidating hypothesis that links these phenomena together has not appeared. Here, we outline a "thionitrate oxidation hypothesis," which attempts to link nitrate bioactivation and tolerance development in an overall mechanism. We also attempt to compare and contrast the proposed mechanism against existing theories of nitrate action and tolerance. Interactions between organic nitrates, which have been thought of as endothelium-independent agents, and the vascular endothelium and endothelial nitric oxide synthase (eNOS) are also discussed.
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Affiliation(s)
- Ho-Leung Fung
- Department of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences, University at Buffalo, Buffalo, New York 14260-1200, USA.
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Perings SM, Grubert N, Kleinbongard P, Reinecke P, Schulz R, Hermsen D, Willers R, Kelm M. Chronic treatment with fluvastatin improves smooth muscle dilatory function in genetically determined hyperlipoproteinemia. J Cardiovasc Pharmacol 2004; 43:183-90. [PMID: 14716204 DOI: 10.1097/00005344-200402000-00004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
We hypothesized that the HMG-CoA reductase inhibitor fluvastatin, does not only improve endothelium-dependent vasorelaxation, but that it also increases vascular smooth muscle reactivity in hyperlipoproteinemia. New Zealand White (NZW) rabbits aged 37 weeks (control), Watanabe Heritable Hyperlipidemic rabbits (WHHL) aged 37 weeks, and WHHL aged 35 weeks with fluvastatin treatment of 17 weeks (10 mg/kg/d) were examined. Aortas were isolated for isometric tension recording. Both endothelium-dependent and independent relaxation were impaired in WHHL. Fluvastatin significantly restored impaired endothelium-independent relaxation (WHHL: 57 +/- 12 versus WHHL+ fluvastatin: 150 +/- 22%; P < 0.05) and in tendency endothelium-dependent relaxation (WHHL: 26 +/- 5 versus WHHL+ fluvastatin: 83 +/- 29%; (P = 0.07)). In parallel, fluvastatin restored nitrite plasma level in hyperlipoproteinemic animals (WHHL: 480 (13-3821) versus WHHL+ fluvastatin: 808 (467-1595) nmol; P < 0.05). Thus, chronic treatment with fluvastatin not only improves endothelial but also vascular smooth muscle function in hyperlipoproteinemia, which may contribute to the beneficial clinical effects of statins.
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Affiliation(s)
- Stefan Martin Perings
- Department of Medicine, Division of Cardiology, Pulmonary Disease, and Angiology, Heinrich Heine University, Düsseldorf, Germany.
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Nakae I, Matsumoto T, Omura T, Takashima H, Ohira N, Tarutani Y, Yasuda Y, Matsuo S, Koh T, Nakaura Y, Kinoshita M, Horie M. Endothelial modulation and tolerance development in the vasorelaxant responses to nitrate of rabbit aorta. Life Sci 2003; 73:3083-94. [PMID: 14550849 DOI: 10.1016/j.lfs.2003.04.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We investigated the endothelial modulations in nitrate tolerance in isolated rabbit aorta. Nitrate tolerance was induced by a 72-h treatment with transdermal nitroglycerin (NTG, 0.4 mg/h) in conscious rabbits, which was verified by a 20-fold increase in the EC50 values [NTG tolerance (6.1 +/- 0.8) x 10(-7) M vs control (3.0 +/- 0.6) x 10(-8) M]. The relaxations to NTG in tolerant and nontolerant aortic strips were enhanced when their endothelia were denuded [E(-)]. In the presence of endothelium [E(+)], NTG-tolerant vessels were not tolerant to acetylcholine (ACh), which can release endothelial nitric oxide (NO), exogenous NO or 8-bromo (Br)-cGMP. In NTG-tolerant and nontolerant vessels with endothelium, concentration-response curves for NO were the same as those in endothelium-absent tolerant vessels. In both NTG-tolerant and nontolerant vessels, treatment with superoxide dismutase (SOD, 20 units/ml), an O2-. scavenger, unaffected the responses to NTG reduced in the presence of endothelium, but treatment with NG-nitro-L-arginine methyl ester (L-NAME, 10(-4) M), an NO synthase (NOS) inhibitor, reversed these reductions. Thus, our data did not indicate that an increased endothelial superoxide O2-. production contributes to nitrate tolerance. Our study suggested that (i) an impaired biotransformation process from NTG to NO is responsible for the occurrence of nitrate tolerance and (ii) vascular response to NTG enhanced by endothelial removal is related to blocked endothelial NO release.
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Affiliation(s)
- Ichiro Nakae
- Department of Cardiovascular and Respiratory Medicine, Shiga University of Medical Science, Seta, Otsu 520-2192, Japan
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Rimar D, Crystal E, Battler A, Gottlieb S, Freimark D, Hod H, Boyko V, Mandelzweig L, Behar S, Leor J. Improved prognosis of patients presenting with clinical markers of spontaneous reperfusion during acute myocardial infarction. Heart 2002; 88:352-6. [PMID: 12231590 PMCID: PMC1767387 DOI: 10.1136/heart.88.4.352] [Citation(s) in RCA: 123] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
OBJECTIVE To describe the clinical features, management, and prognosis of patients presenting with clinical markers of spontaneous reperfusion (SR) during acute myocardial infarction (AMI). DESIGN Cohort study. SETTING National registry of 26 coronary care units. PATIENTS 2382 consecutive patients with AMI. MAIN OUTCOME MEASURES Patient characteristics, management, and mortality. RESULTS The incidence of SR was 4% of patients (n = 98) compared with thrombolytic treatment (n = 1163, 49%), primary angioplasty (n = 102, 4%), and non-reperfusion (n = 1019, 43%). SR patients were more likely to develop less or no myocardial damage as indicated by a higher percentage of non-Q wave AMI (58% v 32%, 47%, and 44%, respectively, p < 0.0001), aborted AMI (25% v 9%, 8%, and 12%, p < 0.001), and lower peak creatine kinase (503 v 1384, 1519, and 751 IU, p < 0.0001). SR patients, however, were more likely to develop recurrent ischaemic events (35% v 17%, 12%, and 16%, respectively; p < 0.001) and subsequently were more likely to be referred to coronary angiography (67%), angioplasty (41%), or bypass surgery (16%, p < 0.001). Mortality at 30 days (1% v 8%, 7%, and 13%, respectively, p < 0.0001) and one year (6% v 11%, 12%, and 19%, p < 0.0001) was significantly lower for SR patients than for the other subgroups. By multivariate analysis, SR remained a strong determinant of 30 day survival (odds ratio (OR) 0.16, 95% confidence interval (CI) 0.01 to 0.74). At one year, the association between SR and survival decreased (OR 0.49, 95% CI 0.18 to 1.13). CONCLUSIONS Clinical markers of SR are associated with greater myocardial salvage and favourable prognosis. The vulnerability of SR patients to recurrent ischaemic events suggests that they need close surveillance and may benefit from early intervention.
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Affiliation(s)
- D Rimar
- Cardiology Department, Soroka Medical Center, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
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Chen Z, Zhang J, Stamler JS. Identification of the enzymatic mechanism of nitroglycerin bioactivation. Proc Natl Acad Sci U S A 2002; 99:8306-11. [PMID: 12048254 PMCID: PMC123063 DOI: 10.1073/pnas.122225199] [Citation(s) in RCA: 402] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Nitroglycerin (glyceryl trinitrate, GTN), originally manufactured by Alfred Nobel, has been used to treat angina and heart failure for over 130 years. However, the molecular mechanism of GTN biotransformation has remained a mystery and it is not well understood why "tolerance" (i.e., loss of clinical efficacy) manifests over time. Here we purify a nitrate reductase that specifically catalyzes the formation of 1,2-glyceryl dinitrate and nitrite from GTN, leading to production of cGMP and relaxation of vascular smooth muscle both in vitro and in vivo, and we identify it as mitochondrial aldehyde dehydrogenase (mtALDH). We also show that mtALDH is inhibited in blood vessels made tolerant by GTN. These results demonstrate that the biotransformation of GTN occurs predominantly in mitochondria through a novel reductase action of mtALDH and suggest that nitrite is an obligate intermediate in generation of NO bioactivity. The data also indicate that attenuated biotransformation of GTN by mtALDH underlies the induction of nitrate tolerance. More generally, our studies provide new insights into subcellular processing of NO metabolites and suggest new approaches to generating NO bioactivity and overcoming nitrate tolerance.
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Affiliation(s)
- Zhiqiang Chen
- Departments of Medicine and Biochemistry, Howard Hughes Medical Institute, Duke University Medical Center, Durham, NC 27710, USA
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Schulz E, Tsilimingas N, Rinze R, Reiter B, Wendt M, Oelze M, Woelken-Weckmüller S, Walter U, Reichenspurner H, Meinertz T, Münzel T. Functional and biochemical analysis of endothelial (dys)function and NO/cGMP signaling in human blood vessels with and without nitroglycerin pretreatment. Circulation 2002; 105:1170-5. [PMID: 11889009 DOI: 10.1161/hc1002.105186] [Citation(s) in RCA: 120] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND In experimental animal models, long-term in vivo treatment with nitroglycerin (NTG) induces both endothelial dysfunction and tolerance to nitrates. However, it is still controversial whether nitrate tolerance in humans is associated with both endothelial dysfunction and impaired vascular response to nitrovasodilator-derived NO. METHODS AND RESULTS Patients undergoing elective bypass surgery were randomized to receive 48 hours of continuous NTG infusion (NTG group) or no nitrate therapy (control group). Segments of surgically removed arteria mammaria, vena saphena, and arteria radialis not required for the bypass procedure were used to examine (1) the vascular responsiveness to NTG and the endothelium-dependent vasodilator acetylcholine; (2) the expression of the NO target, the soluble guanylyl cyclase; (3) the expression of the soluble guanylyl cyclase/cGMP effector target, the cGMP-dependent protein kinase (cGK); and (4) the cGK activity as assessed by the phosphorylation state of its vascular substrate, the vasodilator-stimulated phosphoprotein at serine(239) (P-VASP). NTG treatment caused a marked degree of nitrate tolerance in all 3 vessel types studied and a significant cross-tolerance to the endothelium-dependent vasodilator acetylcholine in A. mammaria and A. radialis. Although soluble guanylyl cyclase, cGK-I, and VASP expression levels were not modified by NTG treatment, a marked decrease of P-VASP, a surrogate parameter for in-vivo cGK-I activity, was observed. CONCLUSIONS We conclude that long-term NTG treatment induces endothelial dysfunction and impaired vascular NO/cGMP signaling in humans, which can be monitored by measuring P-VASP levels.
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Affiliation(s)
- Eberhard Schulz
- University Hospital Eppendorf, Division of Cardiology, Hamburg, Germany
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Elkayam U, Khan S, Mehboob A, Ahsan N. Impaired endothelium-mediated vasodilation in heart failure: clinical evidence and the potential for therapy. J Card Fail 2002; 8:15-20. [PMID: 11862578 DOI: 10.1054/jcaf.2002.31910] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Numerous studies in the last decade have clearly shown an attenuated endothelium-dependent vasodilation in patients with chronic heart failure. This abnormality has been demonstrated in the peripheral, pulmonary, and coronary circulation in patients with both ischemic and nonischemic cardiomyopathy; its magnitude correlates with the severity of symptoms. Endothelial dysfunction in patients with cardiomyopathy and a relatively new onset of symptoms suggests that change in endothelial function occurs early in the course of the disease. In contrast to other circulatory beds, renal circulation has shown significant vasodilatory response to endothelial stimulation. The development of endothelial dysfunction may not be homogeneous, and its magnitude may differ among circulatory systems. Although the clinical implications of the attenuated endothelium-dependent vasodilation in heart failure are not clear, this condition may lead to decreased organ perfusion, impaired exercise tolerance, and progression of disease. Many therapeutic interventions have resulted in improvement of endothelial function in patients with heart failure. Some of these interventions have also proven effective in enhancing exercise capacity, symptoms, and survival in patients with heart failure. This association suggests a therapeutic role for improvement of endothelial function in patients with chronic heart failure.
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Affiliation(s)
- Uri Elkayam
- Heart Failure Program, Division of Cardiology, Department of Medicine, University of Southern California School of Medicine, Los Angeles, CA 90033, USA
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