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Azoury SC, Matros E. Top 25 Medications the Plastic and Reconstructive Surgery Trainee Should Know for an Emergency Medicine Department Consult. Plast Reconstr Surg 2024; 153:474e-489e. [PMID: 37141488 DOI: 10.1097/prs.0000000000010609] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
SUMMARY Plastic surgery trainees are often called to render care in the emergency department (eg, for established patients, trauma, burns). Broad-based knowledge in pharmacotherapeutics during these encounters is critical. This includes an understanding of pain medications, anxiolytics, local anesthetics, antibiotics, anticoagulants, antidotes, and more to ensure optimal patient care. The purpose of this report is to describe 25 frequently used and other important medications that plastic surgery trainees should know for an adult emergency department encounter.
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Affiliation(s)
- Saïd C Azoury
- From the Division of Plastic Surgery, Department of Surgery, University of Pennsylvania
| | - Evan Matros
- Division of Plastic Surgery, Department of Surgery, Memorial Sloan Kettering Cancer Center
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Russell TM, Richardson DR. Glutathione-S-Transferases as Potential Targets for Modulation of Nitric Oxide-Mediated Vasodilation. Biomolecules 2022; 12:biom12091292. [PMID: 36139130 PMCID: PMC9496536 DOI: 10.3390/biom12091292] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Revised: 09/08/2022] [Accepted: 09/09/2022] [Indexed: 11/16/2022] Open
Abstract
Glutathione-S-transferases (GSTs) are highly promiscuous in terms of their interactions with multiple proteins, leading to various functions. In addition to their classical detoxification roles with multi-drug resistance-related protein-1 (MRP1), more recent studies have indicated the role of GSTs in cellular nitric oxide (NO) metabolism. Vasodilation is classically induced by NO through its interaction with soluble guanylate cyclase. The ability of GSTs to biotransform organic nitrates such as nitroglycerin for NO generation can markedly modulate vasodilation, with this effect being prevented by specific GST inhibitors. Recently, other structurally distinct pro-drugs that generate NO via GST-mediated catalysis have been developed as anti-cancer agents and also indicate the potential of GSTs as suitable targets for pharmaceutical development. Further studies investigating GST biochemistry could enhance our understanding of NO metabolism and lead to the generation of novel and innovative vasodilators for clinical use.
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Affiliation(s)
- Tiffany M. Russell
- Centre for Cancer Cell Biology and Drug Discovery, Griffith Institute for Drug Discovery, Griffith University, Brisbane 4111, Australia
| | - Des R. Richardson
- Department of Pathology and Biological Responses, Graduate School of Medicine, Nagoya University, Nagoya 466-8550, Japan
- Correspondence: ; Tel.: +61-7-3735-7549
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Horton A, Schiefer IT. Pharmacokinetics and pharmacodynamics of nitric oxide mimetic agents. Nitric Oxide 2019; 84:69-78. [PMID: 30641123 DOI: 10.1016/j.niox.2019.01.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Revised: 01/02/2019] [Accepted: 01/03/2019] [Indexed: 10/27/2022]
Abstract
Drug discovery focusing on NO mimetics has been hamstrung due to its unconventional nature. Central to these challenges is the fact that direct measurement of molecular NO in biological systems is exceedingly difficulty. Hence, drug development of NO mimetics must rely upon measurement of the NO donating specie (i.e., a prodrug) and a downstream marker of efficacy without directly measuring the molecule, NO, that is responsible for biological effect. The focus of this review is to catalog in vivo attempts to monitor the pharmacokinetics (PK) of the NO donating specie and the pharmacodynamic (PD) readout of NO bioactivity.
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Affiliation(s)
- Austin Horton
- Department of Medicinal and Biological Chemistry, College of Pharmacy and Pharmaceutical Sciences, University of Toledo, Toledo, USA
| | - Isaac T Schiefer
- Department of Medicinal and Biological Chemistry, College of Pharmacy and Pharmaceutical Sciences, University of Toledo, Toledo, USA.
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Hollas MA, Ben Aissa M, Lee SH, Gordon-Blake JM, Thatcher GRJ. Pharmacological manipulation of cGMP and NO/cGMP in CNS drug discovery. Nitric Oxide 2018; 82:59-74. [PMID: 30394348 DOI: 10.1016/j.niox.2018.10.006] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Revised: 08/14/2018] [Accepted: 10/25/2018] [Indexed: 12/21/2022]
Abstract
The development of small molecule modulators of NO/cGMP signaling for use in the CNS has lagged far behind the use of such clinical agents in the periphery, despite the central role played by NO/cGMP in learning and memory, and the substantial evidence that this signaling pathway is perturbed in neurodegenerative disorders, including Alzheimer's disease. The NO-chimeras, NMZ and Nitrosynapsin, have yielded beneficial and disease-modifying responses in multiple preclinical animal models, acting on GABAA and NMDA receptors, respectively, providing additional mechanisms of action relevant to synaptic and neuronal dysfunction. Several inhibitors of cGMP-specific phosphodiesterases (PDE) have replicated some of the actions of these NO-chimeras in the CNS. There is no evidence that nitrate tolerance is a phenomenon relevant to the CNS actions of NO-chimeras, and studies on nitroglycerin in the periphery continue to challenge the dogma of nitrate tolerance mechanisms. Hybrid nitrates have shown much promise in the periphery and CNS, but to date only one treatment has received FDA approval, for glaucoma. The potential for allosteric modulation of soluble guanylate cyclase (sGC) in brain disorders has not yet been fully explored nor exploited; whereas multiple applications of PDE inhibitors have been explored and many have stalled in clinical trials.
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Affiliation(s)
- Michael A Hollas
- Department of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, University of Illinois at Chicago, Chicago, USA
| | - Manel Ben Aissa
- Department of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, University of Illinois at Chicago, Chicago, USA
| | - Sue H Lee
- Department of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, University of Illinois at Chicago, Chicago, USA
| | - Jesse M Gordon-Blake
- Department of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, University of Illinois at Chicago, Chicago, USA
| | - Gregory R J Thatcher
- Department of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, University of Illinois at Chicago, Chicago, USA.
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Daiber A, Münzel T. Organic Nitrate Therapy, Nitrate Tolerance, and Nitrate-Induced Endothelial Dysfunction: Emphasis on Redox Biology and Oxidative Stress. Antioxid Redox Signal 2015; 23:899-942. [PMID: 26261901 PMCID: PMC4752190 DOI: 10.1089/ars.2015.6376] [Citation(s) in RCA: 107] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Organic nitrates, such as nitroglycerin (GTN), isosorbide-5-mononitrate and isosorbide dinitrate, and pentaerithrityl tetranitrate (PETN), when given acutely, have potent vasodilator effects improving symptoms in patients with acute and chronic congestive heart failure, stable coronary artery disease, acute coronary syndromes, or arterial hypertension. The mechanisms underlying vasodilation include the release of •NO or a related compound in response to intracellular bioactivation (for GTN, the mitochondrial aldehyde dehydrogenase [ALDH-2]) and activation of the enzyme, soluble guanylyl cyclase. Increasing cyclic guanosine-3',-5'-monophosphate (cGMP) levels lead to an activation of the cGMP-dependent kinase I, thereby causing the relaxation of the vascular smooth muscle by decreasing intracellular calcium concentrations. The hemodynamic and anti-ischemic effects of organic nitrates are rapidly lost upon long-term (low-dose) administration due to the rapid development of tolerance and endothelial dysfunction, which is in most cases linked to increased intracellular oxidative stress. Enzymatic sources of reactive oxygen species under nitrate therapy include mitochondria, NADPH oxidases, and an uncoupled •NO synthase. Acute high-dose challenges with organic nitrates cause a similar loss of potency (tachyphylaxis), but with distinct pathomechanism. The differences among organic nitrates are highlighted regarding their potency to induce oxidative stress and subsequent tolerance and endothelial dysfunction. We also address pleiotropic effects of organic nitrates, for example, their capacity to stimulate antioxidant pathways like those demonstrated for PETN, all of which may prevent adverse effects in response to long-term therapy. Based on these considerations, we will discuss and present some preclinical data on how the nitrate of the future should be designed.
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Affiliation(s)
- Andreas Daiber
- The 2nd Medical Clinic, Medical Center of the Johannes Gutenberg University , Mainz, Germany
| | - Thomas Münzel
- The 2nd Medical Clinic, Medical Center of the Johannes Gutenberg University , Mainz, Germany
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6
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Schmidt K, Neubauer A, Kolesnik B, Stasch JP, Werner ER, Gorren ACF, Mayer B. Tetrahydrobiopterin protects soluble guanylate cyclase against oxidative inactivation. Mol Pharmacol 2012; 82:420-7. [PMID: 22648973 DOI: 10.1124/mol.112.079855] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Tetrahydrobiopterin (BH4) is a major endogenous vasoprotective agent that improves endothelial function by increasing nitric oxide (NO) synthesis and scavenging of superoxide and peroxynitrite. Therefore, administration of BH4 is considered a promising therapy for cardiovascular diseases associated with endothelial dysfunction and oxidative stress. Here we report on a novel function of BH4 that might contribute to the beneficial vascular effects of the pteridine. Treatment of cultured porcine aortic endothelial cells with nitroglycerin (GTN) or 1H-[1,2,4]-oxadiazolo[4,3-a]quinoxaline-1-one (ODQ) resulted in heme oxidation of soluble guanylate cyclase (sGC), as evident from diminished NO-induced cGMP accumulation that was paralleled by increased cGMP response to a heme- and NO-independent activator of soluble guanylate cyclase [4-([(4-carboxybutyl)[2-(5-fluoro-2-([4'-(trifluoromethyl)biphenyl-4-yl]methoxy)phenyl)ethyl]amino]methyl)benzoic acid (BAY 60-2770)]. Whereas scavenging of superoxide and/or peroxynitrite with superoxide dismutase, tiron, Mn(III)tetrakis(4-benzoic acid)porphyrin, and urate had no protective effects, supplementation of the cells with BH4, either by application of BH4 directly or of its precursors dihydrobiopterin or sepiapterin, completely prevented the inhibition of NO-induced cGMP accumulation by GTN and ODQ. Tetrahydroneopterin had the same effect, and virtually identical results were obtained with RFL-6 fibroblasts, suggesting that our observation reflects a general feature of tetrahydropteridines that is unrelated to NO synthase function and not limited to endothelial cells. Protection of sGC against oxidative inactivation may contribute to the known beneficial effects of BH4 in cardiovascular disorders associated with oxidative stress.
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Affiliation(s)
- Kurt Schmidt
- Department of Pharmacology and Toxicology, Karl-Franzens-Universität Graz, Graz, Austria.
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7
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Wenzl MV, Beretta M, Griesberger M, Russwurm M, Koesling D, Schmidt K, Mayer B, Gorren ACF. Site-directed mutagenesis of aldehyde dehydrogenase-2 suggests three distinct pathways of nitroglycerin biotransformation. Mol Pharmacol 2011; 80:258-66. [PMID: 21536753 DOI: 10.1124/mol.111.071704] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
To elucidate the mechanism underlying reduction of nitroglycerin (GTN) to nitric oxide (NO) by mitochondrial aldehyde dehydrogenase (ALDH2), we generated mutants of the enzyme lacking the cysteines adjacent to reactive Cys302 (C301S and C303S), the glutamate that participates as a general base in aldehyde oxidation (E268Q) or combinations of these residues. The mutants were characterized regarding acetaldehyde dehydrogenation, GTN-triggered enzyme inactivation, GTN denitration, NO formation, and soluble guanylate cyclase activation. Lack of the cysteines did not affect dehydrogenase activity but impeded GTN denitration, aggravated GTN-induced enzyme inactivation, and increased NO formation. A triple mutant lacking the cysteines and Glu268 catalyzed sustained formation of superstoichiometric amounts of NO and exhibited slower rates of inactivation. These results suggest three alternative pathways for the reaction of ALDH2 with GTN, all involving formation of a thionitrate/sulfenyl nitrite intermediate at Cys302 as the initial step. In the first pathway, which predominates in the wild-type enzyme and reflects clearance-based GTN denitration, the thionitrate apparently reacts with one of the adjacent cysteine residues to yield nitrite and a protein disulfide. The predominant reaction catalyzed by the single and double cysteine mutants requires Glu268 and results in irreversible enzyme inactivation. Finally, combined lack of the cysteines and Glu268 shifts the reaction toward formation of the free NO radical, presumably through homolytic cleavage of the sulfenyl nitrite intermediate. Although the latter reaction accounts for less than 10% of total turnover of GTN metabolism catalyzed by wild-type ALDH2, it is most likely essential for vascular GTN bioactivation.
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Affiliation(s)
- M Verena Wenzl
- Department of Pharmacology and Toxicology, Karl-Franzens-Universität Graz, Universitätsplatz 2, A-8010, Austria.
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Schade D, Kotthaus J, Clement B. Modulating the NO generating system from a medicinal chemistry perspective: Current trends and therapeutic options in cardiovascular disease. Pharmacol Ther 2010; 126:279-300. [DOI: 10.1016/j.pharmthera.2010.02.005] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2010] [Accepted: 02/10/2010] [Indexed: 01/05/2023]
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Schmidt K, Rehn M, Stessel H, Wölkart G, Mayer B. Evidence against tetrahydrobiopterin depletion of vascular tissue exposed to nitric oxide/superoxide or nitroglycerin. Free Radic Biol Med 2010; 48:145-52. [PMID: 19853656 DOI: 10.1016/j.freeradbiomed.2009.10.038] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/21/2009] [Revised: 09/15/2009] [Accepted: 10/16/2009] [Indexed: 11/22/2022]
Abstract
Several cardiovascular disorders, including atherosclerosis and tolerance to the antianginal drug nitroglycerin (GTN), may be associated with the generation of superoxide anions, which react with nitric oxide (NO) to yield peroxynitrite. According to a widely held view, oxidation of tetrahydrobiopterin (BH(4)) by peroxynitrite causes uncoupling of endothelial NO synthase (eNOS), resulting in reduced NO bioavailability and endothelial dysfunction under conditions of oxidative stress. In this study we determined the levels of reduced biopterins and endothelial function in cultured cells exposed to peroxynitrite and GTN as well as in blood vessels isolated from GTN-tolerant guinea pigs and rats. BH(4) was rapidly oxidized by peroxynitrite and 3-morpholino sydnonimine (SIN-1) in buffer, but this was prevented by glutathione and not observed in endothelial cells exposed to SIN-1 or GTN. Prolonged treatment of the cells with 0.1 mM GTN caused slow N(G)-nitro-l-arginine-sensitive formation of reactive oxygen species without affecting eNOS activity. Endothelial function and BH(4)/BH(2) levels were identical in blood vessels of control and GTN-tolerant animals. Our results suggest that peroxynitrite-triggered BH(4) oxidation does not occur in endothelial cells or GTN-exposed blood vessels. GTN seems to trigger minor eNOS uncoupling that is unrelated to BH(4) depletion and without observable consequence on eNOS function.
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Affiliation(s)
- Kurt Schmidt
- Department of Pharmacology and Toxicology, Karl-Franzens-Universität Graz, A-8010 Graz, Austria
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10
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Daiber A, Münzel T, Gori T. Organic nitrates and nitrate tolerance--state of the art and future developments. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2010; 60:177-227. [PMID: 21081219 DOI: 10.1016/b978-0-12-385061-4.00007-6] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The hemodynamic and antiischemic effects of nitroglycerin (GTN) are lost upon chronic administration due to the rapid development of nitrate tolerance. The mechanism of this phenomenon has puzzled several generations of scientists, but recent findings have led to novel hypotheses. The formation of reactive oxygen and nitrogen species in the mitochondria and the subsequent inhibition of the nitrate-bioactivating enzyme mitochondrial aldehyde dehydrogenase (ALDH-2) appear to play a central role, at least for GTN, that is, bioactivated by ALDH-2. Importantly, these findings provide the opportunity to reconcile the two "traditional" hypotheses of nitrate tolerance, that is, the one postulating a decreased bioactivation and the concurrent one suggesting a role of oxidative stress. Furthermore, recent animal and human experimental studies suggest that the organic nitrates are not a homogeneous group but demonstrate a broad diversity with regard to induction of vascular dysfunction, oxidative stress, and other side effects. In the past, attempts to avoid nitrate-induced side effects have focused on administration schedules that would allow a "nitrate-free interval"; in the future, the role of co-therapies with antioxidant compounds and of activation of endogeneous protective pathways such as the heme oxygenase 1 (HO-1) will need to be explored. However, the development of new nitrates, for example, tolerance-free aminoalkyl nitrates or combination of nitrate groups with established cardiovascular drugs like ACE inhibitors or AT(1)-receptor blockers (hybrid molecules) may be of great clinical interest.
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Affiliation(s)
- Andreas Daiber
- II. Medizinische Klinik, Labor für Molekulare Kardiologie und Abteilung für Kardiologie und Angiologie, Universitätsmedizin der Johannes-Gutenberg-Universität, Mainz, Germany
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Beretta M, Sottler A, Schmidt K, Mayer B, Gorren ACF. Partially irreversible inactivation of mitochondrial aldehyde dehydrogenase by nitroglycerin. J Biol Chem 2008; 283:30735-44. [PMID: 18786921 PMCID: PMC2576553 DOI: 10.1074/jbc.m804001200] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Mitochondrial aldehyde dehydrogenase (ALDH2) may be involved in the
biotransformation of glyceryl trinitrate (GTN), and the inactivation of ALDH2
by GTN may contribute to the phenomenon of nitrate tolerance. We studied the
GTN-induced inactivation of ALDH2 by UV/visible absorption spectroscopy.
Dehydrogenation of acetaldehyde and hydrolysis of
p-nitrophenylacetate (p-NPA) were both inhibited by GTN. The
rate of inhibition increased with the GTN concentration and decreased with the
substrate concentration, indicative of competition between GTN and the
substrates. Inactivation of p-NPA hydrolysis was greatly enhanced in
the presence of NAD+, and, to a lesser extent, in the presence of
NADH. In the presence of dithiothreitol (DTT) inactivation of ALDH2 was much
slower. Dihydrolipoic acid (LPA-H2) was less effective than DTT,
whereas glutathione, cysteine, and ascorbate did not protect against
inactivation. When DTT was added after complete inactivation, dehydrogenase
reactivation was quite modest (≤16%). The restored dehydrogenase activity
correlated inversely with the GTN concentration but was hardly affected by the
concentrations of acetaldehyde or DTT. Partial reactivation of dehydrogenation
was also accomplished by LPA-H2 but not by GSH. We conclude that,
in addition to the previously documented reversible inhibition by GTN that can
be ascribed to the oxidation of the active site thiol, there is an
irreversible component to ALDH inactivation. Importantly, ALDH2-catalyzed GTN
reduction was partly inactivated by preincubation with GTN, suggesting that
the inactivation of GTN reduction is also partly irreversible. These
observations are consistent with a significant role for irreversible
inactivation of ALDH2 in the development of nitrate tolerance.
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Affiliation(s)
- Matteo Beretta
- Department of Pharmacology and Toxicology, Karl-Franzens-Universität Graz, A-8010 Graz, Austria
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Mayer B, Beretta M. The enigma of nitroglycerin bioactivation and nitrate tolerance: news, views and troubles. Br J Pharmacol 2008; 155:170-84. [PMID: 18574453 PMCID: PMC2538691 DOI: 10.1038/bjp.2008.263] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2008] [Revised: 05/28/2008] [Accepted: 06/03/2008] [Indexed: 02/07/2023] Open
Abstract
Nitroglycerin (glyceryl trinitrate; GTN) is the most prominent representative of the organic nitrates or nitrovasodilators, a class of compounds that have been used clinically since the late nineteenth century for the treatment of coronary artery disease (angina pectoris), congestive heart failure and myocardial infarction. Medline lists more than 15 000 publications on GTN and other organic nitrates, but the mode of action of these drugs is still largely a mystery. In the first part of this article, we give an overview on the molecular mechanisms of GTN biotransformation resulting in vascular cyclic GMP accumulation and vasodilation with focus on the role of mitochondrial aldehyde dehydrogenase (ALDH2) and the link between the ALDH2 reaction and activation of vascular soluble guanylate cyclase (sGC). In particular, we address the identity of the bioactive species that activates sGC and the potential involvement of nitrite as an intermediate, describe our recent findings suggesting that ALDH2 catalyses direct 3-electron reduction of GTN to NO and discuss possible reaction mechanisms. In the second part, we discuss contingent processes leading to markedly reduced sensitivity of blood vessels to GTN, referred to as vascular nitrate tolerance. Again, we focus on ALDH2 and describe the current controversy on the role of ALDH2 inactivation in tolerance development. Finally, we emphasize some of the most intriguing, in our opinion, unresolved puzzles of GTN pharmacology that urgently need to be addressed in future studies.
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Affiliation(s)
- B Mayer
- Department of Pharmacology and Toxicology, Karl-Franzens-University Graz, Graz, Austria.
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Beretta M, Gruber K, Kollau A, Russwurm M, Koesling D, Goessler W, Keung WM, Schmidt K, Mayer B. Bioactivation of nitroglycerin by purified mitochondrial and cytosolic aldehyde dehydrogenases. J Biol Chem 2008; 283:17873-80. [PMID: 18450747 PMCID: PMC2440601 DOI: 10.1074/jbc.m801182200] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Metabolism of nitroglycerin (GTN) to 1,2-glycerol dinitrate (GDN) and nitrite by mitochondrial aldehyde dehydrogenase (ALDH2) is essentially involved in GTN bioactivation resulting in cyclic GMP-mediated vascular relaxation. The link between nitrite formation and activation of soluble guanylate cyclase (sGC) is still unclear. To test the hypothesis that the ALDH2 reaction is sufficient for GTN bioactivation, we measured GTN-induced formation of cGMP by purified sGC in the presence of purified ALDH2 and used a Clark-type electrode to probe for nitric oxide (NO) formation. In addition, we studied whether GTN bioactivation is a specific feature of ALDH2 or is also catalyzed by the cytosolic isoform (ALDH1). Purified ALDH1 and ALDH2 metabolized GTN to 1,2- and 1,3-GDN with predominant formation of the 1,2-isomer that was inhibited by chloral hydrate (ALDH1 and ALDH2) and daidzin (ALDH2). GTN had no effect on sGC activity in the presence of bovine serum albumin but caused pronounced cGMP accumulation in the presence of ALDH1 or ALDH2. The effects of the ALDH isoforms were dependent on the amount of added protein and, like 1,2-GDN formation, were sensitive to ALDH inhibitors. GTN caused biphasic sGC activation with apparent EC50 values of 42 ± 2.9 and 3.1 ± 0.4 μm in the presence of ALDH1 and ALDH2, respectively. Incubation of ALDH1 or ALDH2 with GTN resulted in sustained, chloral hydrate-sensitive formation of NO. These data may explain the coupling of ALDH2-catalyzed GTN metabolism to sGC activation in vascular smooth muscle.
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Affiliation(s)
- Matteo Beretta
- Department of Pharmacology and Toxicology, Karl-Franzens-Universität Graz, Graz, Austria
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14
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Wölkart G, Wenzl MV, Beretta M, Stessel H, Schmidt K, Mayer B. Vascular tolerance to nitroglycerin in ascorbate deficiency. Cardiovasc Res 2008; 79:304-12. [PMID: 18442986 DOI: 10.1093/cvr/cvn107] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
AIMS Nitroglycerin (GTN) acts through release of a nitric oxide (NO)-related activator of soluble guanylate cyclase in vascular smooth muscle. Besides enzymatic GTN bioactivation catalysed by aldehyde dehydrogenase, non-enzymatic reaction of GTN with ascorbate also results in the formation of a bioactive product. Using an established guinea pig model of ascorbate deficiency, we investigated whether endogenous ascorbate contributes to GTN-induced vasodilation. METHODS AND RESULTS Guinea pigs were fed either standard or ascorbate-free diet for 2 or 4 weeks prior to measuring the GTN response of aortic rings and isolated hearts. The effects of ascorbate on GTN metabolism were studied with purified mitochondrial aldehyde dehydrogenase (ALDH2) and isolated mitochondria. Ascorbate deprivation led to severe scorbutic symptoms and loss of body weight, but had no (2 weeks) or only slight (4 weeks) effects on aortic relaxations to a direct NO donor. The EC(50) of GTN was increased from 0.058 +/- 0.018 to 0.46 +/- 0.066 and 5.5 +/- 0.9 microM after 2 and 4 weeks of ascorbate-free diet, respectively. Similarly, coronary vasodilation to GTN was severely impaired in ascorbate deficiency. The potency of GTN was reduced to a similar extent by ALDH inhibitors in control and ascorbate-deficient blood vessels. Up to 10 mM ascorbate had no effect on GTN metabolism catalysed by purified ALDH2 or liver mitochondria isolated from ascorbate-deficient guinea pigs. CONCLUSION Our results indicate that prolonged ascorbate deficiency causes tolerance to GTN without affecting NO/cyclic GMP-mediated vasorelaxation.
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Affiliation(s)
- Gerald Wölkart
- Department of Pharmacology and Toxicology, Karl-Franzens-Universität Graz, Universitätsplatz 2, A-8010 Graz, Austria
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15
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Kollau A, Beretta M, Gorren ACF, Russwurm M, Koesling D, Schmidt K, Mayer B. Bioactivation of nitroglycerin by ascorbate. Mol Pharmacol 2007; 72:191-6. [PMID: 17446267 DOI: 10.1124/mol.107.035642] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Bioactivation of nitroglycerin (GTN) into an activator of soluble guanylate cyclase (sGC) is essential for the vasorelaxant effect of the drug. Besides several enzymes that catalyze GTN bioactivation, the reaction with cysteine is the sole nonenzymatic mechanism known so far. Here we show that a reaction with ascorbate results in GTN bioactivation. In the absence of ascorbate, GTN did not affect the activity of purified sGC. However, the enzyme was activated to approximately 20% of maximal NO-stimulated activity by GTN in the presence of 10 mM ascorbate with an EC(50) value of 27.3 +/- 4.9 microM GTN. The EC(50) value of ascorbate was 0.11 +/- 0.011 mM. Activation of sGC was sensitive to oxyhemoglobin, superoxide, and a heme-site enzyme inhibitor. GTN had no effect when ascorbate was replaced by 1000 U of superoxide dismutase per milliliter. Ascorbate is known to reduce inorganic nitrite to NO. In the presence of 10 mM ascorbate, approximately 30 microM nitrite caused the same increase in sGC activity as 0.3 mM GTN. Determination of ascorbate-driven 1,2- and 1,3-glycerol dinitrate formation indicated that a 140 nM concentration of products was generated from 0.3 mM GTN within 10 min, excluding nitrite as a relevant intermediate. Our results suggest that a reaction between GTN and ascorbate or an ascorbate-derived species yields an activator of sGC with NO-like chemical properties. This reaction may contribute to GTN bioactivation in blood vessels under conditions of GTN tolerance and ascorbate supplementation.
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Affiliation(s)
- Alexander Kollau
- Department of Pharmacology and Toxicology, Karl-Franzens-Universität Graz, Universitätsplatz 2, A-8010 Graz, Austria
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Wenzel P, Hink U, Oelze M, Seeling A, Isse T, Bruns K, Steinhoff L, Brandt M, Kleschyov AL, Schulz E, Lange K, Weiner H, Lehmann J, Lackner KJ, Kawamoto T, Münzel T, Daiber A. Number of nitrate groups determines reactivity and potency of organic nitrates: a proof of concept study in ALDH-2-/- mice. Br J Pharmacol 2007; 150:526-33. [PMID: 17220910 PMCID: PMC2189719 DOI: 10.1038/sj.bjp.0707116] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
BACKGROUND AND PURPOSE Mitochondrial aldehyde dehydrogenase (ALDH-2) has been shown to provide a pathway for bioactivation of organic nitrates and to be prone to desensitization in response to highly potent, but not to less potent, nitrates. We therefore sought to support the hypothesis that bioactivation by ALDH-2 critically depends on the number of nitrate groups within the nitrovasodilator. EXPERIMENTAL APPROACH Nitrates with one (PEMN), two (PEDN; GDN), three (PETriN; glyceryl trinitrate, GTN) and four (pentaerithrityl tetranitrate, PETN) nitrate groups were investigated. Vasodilatory potency was measured in isometric tension studies using isolated aortic segments of wild type (WT) and ALDH-2-/- mice. Activity of the cGMP-dependent kinase-I (reflected by levels of phosphorylated VAsodilator Stimulated Phosphoprotein, P-VASP) was quantified by Western blot analysis, mitochondrial dehydrogenase activity by HPLC. Following incubation of isolated mitochondria with PETN, PETriN-chromophore and PEDN, metabolites were quantified using chemiluminescence nitrogen detection and mass spectrometry. KEY RESULTS Compared to WT, vasorelaxation in response to PETN, PETriN and GTN was attenuated about 10fold in ALDH-2-/- mice, identical to WT vessels preincubated with inhibitors of ALDH-2. Reduced vasodilator potency correlated with reduced P-VASP formation and diminished biotransformation of the tetranitrate- and trinitrate-compounds. None of these findings were observed for PEDN, GDN and PEMN. CONCLUSIONS AND IMPLICATIONS Our results support the crucial role of ALDH-2 in bioactivating highly reactive nitrates like GTN, PETN and PETriN. ALDH-2-mediated relaxation by organic nitrates therefore depends mainly on the number of nitrate groups. Less potent nitrates like PEDN, GDN and PEMN are apparently biotransformed by other pathways.
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Affiliation(s)
- P Wenzel
- II. Medizinische Klinik der Johannes-Gutenberg-Universität Mainz Mainz, Germany
| | - U Hink
- II. Medizinische Klinik der Johannes-Gutenberg-Universität Mainz Mainz, Germany
| | - M Oelze
- II. Medizinische Klinik der Johannes-Gutenberg-Universität Mainz Mainz, Germany
| | - A Seeling
- Institut für Pharmazie, Lehrstuhl für pharmazeutische Chemie, Friedrich-Schiller-Universität Jena Philosophenweg, Jena, Germany
| | - T Isse
- Department of Environmental Health, University of Occupational and Environmental Health Yahatanishi, Kitakyushu, Japan
| | - K Bruns
- Institut für Klinische Chemie und Laboratoriumsmedizin, Klinik der Johannes-Gutenberg-Universität Mainz Mainz, Germany
| | - L Steinhoff
- II. Medizinische Klinik der Johannes-Gutenberg-Universität Mainz Mainz, Germany
| | - M Brandt
- II. Medizinische Klinik der Johannes-Gutenberg-Universität Mainz Mainz, Germany
| | - A L Kleschyov
- II. Medizinische Klinik der Johannes-Gutenberg-Universität Mainz Mainz, Germany
| | - E Schulz
- II. Medizinische Klinik der Johannes-Gutenberg-Universität Mainz Mainz, Germany
| | - K Lange
- Institut für Pharmazie, Lehrstuhl für pharmazeutische Chemie, Friedrich-Schiller-Universität Jena Philosophenweg, Jena, Germany
| | - H Weiner
- Department of Biochemistry, Purdue University West Lafayette, Indiana, USA
| | - J Lehmann
- Institut für Pharmazie, Lehrstuhl für pharmazeutische Chemie, Friedrich-Schiller-Universität Jena Philosophenweg, Jena, Germany
| | - K J Lackner
- Institut für Klinische Chemie und Laboratoriumsmedizin, Klinik der Johannes-Gutenberg-Universität Mainz Mainz, Germany
| | - T Kawamoto
- Department of Environmental Health, University of Occupational and Environmental Health Yahatanishi, Kitakyushu, Japan
| | - T Münzel
- II. Medizinische Klinik der Johannes-Gutenberg-Universität Mainz Mainz, Germany
| | - A Daiber
- II. Medizinische Klinik der Johannes-Gutenberg-Universität Mainz Mainz, Germany
- Author for correspondence:
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