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van den Berg TNAD, Thijssen DHJ, van Mil ACCM, van den Broek PH, Rongen GA, Monajemi H, Deinum J, Riksen NP. Plasma levels of the cardiovascular protective endogenous nucleoside adenosine are reduced in patients with primary aldosteronism without affecting ischaemia-reperfusion injury: A prospective case-control study. Eur J Clin Invest 2019; 49:e13180. [PMID: 31659743 PMCID: PMC6900001 DOI: 10.1111/eci.13180] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Revised: 09/04/2019] [Accepted: 10/25/2019] [Indexed: 12/25/2022]
Abstract
BACKGROUND Patients with primary aldosteronism (PA) experience more cardiovascular events compared to patients with essential hypertension (EHT), independent from blood pressure levels. In animals, mineralocorticoid receptor antagonists limit ischaemia-reperfusion (IR) injury by increasing extracellular adenosine formation and adenosine receptor stimulation. Adenosine is an endogenous compound with profound cardiovascular protective effects. Firstly, we hypothesized that patients with PA have lower circulating adenosine levels which might contribute to the observed increased cardiovascular risk. Secondly, we hypothesized that by this mechanism, patients with PA are more susceptible to IR compared to patients with EHT. DESIGN In our prospective study in 20 patients with PA and 20 patients with EHT, circulating adenosine was measured using a pharmacological blocker solution that halts adenosine metabolism after blood drawing. Brachial artery flow-mediated dilation (FMD) before and after forearm IR was used as a well-established method to study IR injury. RESULTS Patients with PA had a 33% lower adenosine level compared to patients with EHT (15.3 [13.3-20.4] vs 22.7 [19.4-36.8] nmol/L, respectively, P < .01). The reduction in FMD after IR, however, did not differ between patients with PA and patients with EHT (-1.0 ± 2.9% vs -1.6 ± 1.6%, respectively, P = .52). CONCLUSIONS As adenosine receptor stimulation induces various powerful protective cardiovascular effects, its lower concentration in patients with PA might be an important novel mechanism that contributes to their increased cardiovascular risk. We suggest that modulation of the adenosine metabolism is an exciting novel pharmacological opportunity to limit cardiovascular risk in patients with PA that needs further exploration.
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Affiliation(s)
- T N A Daniëlle van den Berg
- Department of Pharmacology-Toxicology, Radboud university medical center, Nijmegen, The Netherlands.,Department of Internal Medicine, Radboud university medical center, Nijmegen, The Netherlands
| | - Dick H J Thijssen
- Department of Physiology, Radboud university medical center, Nijmegen, The Netherlands
| | - Anke C C M van Mil
- Department of Physiology, Radboud university medical center, Nijmegen, The Netherlands
| | - Petra H van den Broek
- Department of Pharmacology-Toxicology, Radboud university medical center, Nijmegen, The Netherlands
| | - Gerard A Rongen
- Department of Pharmacology-Toxicology, Radboud university medical center, Nijmegen, The Netherlands.,Department of Internal Medicine, Radboud university medical center, Nijmegen, The Netherlands
| | - Houshang Monajemi
- Department of Internal Medicine, Rijnstate Ziekenhuis, Arnhem, The Netherlands
| | - Jaap Deinum
- Department of Internal Medicine, Radboud university medical center, Nijmegen, The Netherlands.,Department of Internal Medicine III, University Hospital Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
| | - Niels P Riksen
- Department of Internal Medicine, Radboud university medical center, Nijmegen, The Netherlands
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2
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Oyarzún C, Garrido W, Alarcón S, Yáñez A, Sobrevia L, Quezada C, San Martín R. Adenosine contribution to normal renal physiology and chronic kidney disease. Mol Aspects Med 2017; 55:75-89. [PMID: 28109856 DOI: 10.1016/j.mam.2017.01.004] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2016] [Revised: 01/11/2017] [Accepted: 01/13/2017] [Indexed: 12/12/2022]
Abstract
Adenosine is a nucleoside that is particularly interesting to many scientific and clinical communities as it has important physiological and pathophysiological roles in the kidney. The distribution of adenosine receptors has only recently been elucidated; therefore it is likely that more biological roles of this nucleoside will be unveiled in the near future. Since the discovery of the involvement of adenosine in renal vasoconstriction and regulation of local renin production, further evidence has shown that adenosine signaling is also involved in the tubuloglomerular feedback mechanism, sodium reabsorption and the adaptive response to acute insults, such as ischemia. However, the most interesting finding was the increased adenosine levels in chronic kidney diseases such as diabetic nephropathy and also in non-diabetic animal models of renal fibrosis. When adenosine is chronically increased its signaling via the adenosine receptors may change, switching to a state that induces renal damage and produces phenotypic changes in resident cells. This review discusses the physiological and pathophysiological roles of adenosine and pays special attention to the mechanisms associated with switching homeostatic nucleoside levels to increased adenosine production in kidneys affected by CKD.
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Affiliation(s)
- Carlos Oyarzún
- Institute of Biochemistry and Microbiology, Science Faculty, Universidad Austral de Chile, Valdivia, Chile
| | - Wallys Garrido
- Institute of Biochemistry and Microbiology, Science Faculty, Universidad Austral de Chile, Valdivia, Chile
| | - Sebastián Alarcón
- Institute of Biochemistry and Microbiology, Science Faculty, Universidad Austral de Chile, Valdivia, Chile
| | - Alejandro Yáñez
- Institute of Biochemistry and Microbiology, Science Faculty, Universidad Austral de Chile, Valdivia, Chile
| | - Luis Sobrevia
- Cellular and Molecular Physiology Laboratory (CMPL), Division of Obstetrics and Gynaecology, School of Medicine, Faculty of Medicine, Pontificia Universidad Católica de Chile, Santiago 8330024, Chile; Department of Physiology, Faculty of Pharmacy, Universidad de Sevilla, Seville E-41012, Spain; University of Queensland Centre for Clinical Research (UQCCR), Faculty of Medicine and Biomedical Sciences, University of Queensland, Herston QLD 4029, Queensland, Australia
| | - Claudia Quezada
- Institute of Biochemistry and Microbiology, Science Faculty, Universidad Austral de Chile, Valdivia, Chile
| | - Rody San Martín
- Institute of Biochemistry and Microbiology, Science Faculty, Universidad Austral de Chile, Valdivia, Chile.
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3
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Bruzzese L, Fenouillet E, Fromonot J, Durand-Gorde JM, Condo J, Kipson N, Mottola G, Deharo P, Guieu R, Ruf J. High homocysteine levels prevent via H2 S the CoCl2 -induced alteration of lymphocyte viability. J Cell Mol Med 2016; 20:1411-9. [PMID: 27061011 PMCID: PMC4956953 DOI: 10.1111/jcmm.12829] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2015] [Accepted: 02/05/2016] [Indexed: 12/21/2022] Open
Abstract
High homocysteine (HCy) levels are associated with lymphocyte‐mediated inflammatory responses that are sometimes in turn related to hypoxia. Because adenosine is a potent lymphocyte suppressor produced in hypoxic conditions and shares metabolic pathways with HCy, we addressed the influence of high HCy levels on the hypoxia‐induced, adenosine‐mediated, alteration of lymphocyte viability. We treated mitogen‐stimulated human lymphocytes isolated from healthy individuals and the human lymphoma T‐cell line CEM with cobalt chloride (CoCl2)to reproduce hypoxia. We found that CoCl2‐altered cell viability was dose‐dependently reversed using HCy. In turn, the HCy effect was inhibited using DL‐propargylglycine, a specific inhibitor of the hydrogen sulphide (H2S)‐synthesizing enzyme cystathionine‐γ‐lyase involved in HCy catabolism. We then addressed the intracellular metabolic pathway of adenosine and HCy, and the role of the adenosine A2A receptor (A2AR). We observed that: (i) hypoxic conditions lowered the intracellular concentration of HCy by increasing adenosine production, which resulted in high A2AR expression and 3′, 5′‐cyclic adenosine monophosphate production; (ii) increasing intracellular HCy concentration reversed the hypoxia‐induced adenosinergic signalling despite high adenosine concentration by promoting both S‐adenosylhomocysteine and H2S production; (iii) DL‐propargylglycine that inhibits H2S production abolished the HCy effect. Together, these data suggest that high HCy levels prevent, via H2S production and the resulting down‐regulation of A2AR expression, the hypoxia‐induced adenosinergic alteration of lymphocyte viability. We point out the relevance of these mechanisms in the pathophysiology of cardiovascular diseases.
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Affiliation(s)
- Laurie Bruzzese
- UMR-MD2, Marseille Medical School, Aix-Marseille University and IRBA, Northern sector, Marseille, France
| | - Emmanuel Fenouillet
- UMR-MD2, Marseille Medical School, Aix-Marseille University and IRBA, Northern sector, Marseille, France.,CNRS, Institut des Sciences Biologiques, France
| | - Julien Fromonot
- UMR-MD2, Marseille Medical School, Aix-Marseille University and IRBA, Northern sector, Marseille, France.,Laboratory of Biochemistry, Timone University Hospital, Marseille, France
| | - Josée-Martine Durand-Gorde
- UMR-MD2, Marseille Medical School, Aix-Marseille University and IRBA, Northern sector, Marseille, France
| | - Jocelyne Condo
- UMR-MD2, Marseille Medical School, Aix-Marseille University and IRBA, Northern sector, Marseille, France
| | - Nathalie Kipson
- UMR-MD2, Marseille Medical School, Aix-Marseille University and IRBA, Northern sector, Marseille, France
| | - Giovanna Mottola
- UMR-MD2, Marseille Medical School, Aix-Marseille University and IRBA, Northern sector, Marseille, France.,Laboratory of Biochemistry, Timone University Hospital, Marseille, France
| | - Pierre Deharo
- UMR-MD2, Marseille Medical School, Aix-Marseille University and IRBA, Northern sector, Marseille, France.,Cardiology Department, Timone University Hospital, Marseille, France
| | - Régis Guieu
- UMR-MD2, Marseille Medical School, Aix-Marseille University and IRBA, Northern sector, Marseille, France.,Laboratory of Biochemistry, Timone University Hospital, Marseille, France
| | - Jean Ruf
- UMR-MD2, Marseille Medical School, Aix-Marseille University and IRBA, Northern sector, Marseille, France.,INSERM, France
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4
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Kretschmar C, Oyarzún C, Villablanca C, Jaramillo C, Alarcón S, Perez G, Díaz-Encarnación MM, Pastor-Anglada M, Garrido W, Quezada C, San Martín R. Reduced Adenosine Uptake and Its Contribution to Signaling that Mediates Profibrotic Activation in Renal Tubular Epithelial Cells: Implication in Diabetic Nephropathy. PLoS One 2016; 11:e0147430. [PMID: 26808537 PMCID: PMC4726618 DOI: 10.1371/journal.pone.0147430] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2015] [Accepted: 01/03/2016] [Indexed: 11/18/2022] Open
Abstract
Altered nucleoside levels may be linked to pathogenic signaling through adenosine receptors. We hypothesized that adenosine dysregulation contributes to fibrosis in diabetic kidney disease. Our findings indicate that high glucose levels and experimental diabetes decreased uptake activity through the equilibrative nucleoside transporter 1 (ENT1) in proximal tubule cells. In addition, a correlation between increased plasma content of adenosine and a marker of renal fibrosis in diabetic rats was evidenced. At the cellular level, exposure of HK2 cells to high glucose, TGF-β and the general adenosine receptor agonist NECA, induced the expression of profibrotic cell activation markers α-SMA and fibronectin. These effects can be avoided by using a selective antagonist of the adenosine A3 receptor subtype in vitro. Furthermore, induction of fibrosis marker α-SMA was prevented by the A3 receptor antagonist in diabetic rat kidneys. In conclusion, we evidenced the contribution of purinergic signaling to renal fibrosis in experimental diabetic nephropathy.
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Affiliation(s)
- Catalina Kretschmar
- Institute of Biochemistry and Microbiology, Science Faculty, Universidad Austral de Chile, Valdivia, Chile
| | - Carlos Oyarzún
- Institute of Biochemistry and Microbiology, Science Faculty, Universidad Austral de Chile, Valdivia, Chile
| | - Cristopher Villablanca
- Institute of Biochemistry and Microbiology, Science Faculty, Universidad Austral de Chile, Valdivia, Chile
| | - Catherinne Jaramillo
- Institute of Biochemistry and Microbiology, Science Faculty, Universidad Austral de Chile, Valdivia, Chile
| | - Sebastián Alarcón
- Institute of Biochemistry and Microbiology, Science Faculty, Universidad Austral de Chile, Valdivia, Chile
| | - Gustavo Perez
- Institute of Biochemistry and Microbiology, Science Faculty, Universidad Austral de Chile, Valdivia, Chile
| | | | - Marçal Pastor-Anglada
- Institute of Biomedicine and Oncology Programme, National Biomedical Research Institute of Liver and Gastrointestinal Diseases (CIBER EHD), Department of Biochemistry and Molecular Biology, University of Barcelona, Barcelona, Spain
| | - Wallys Garrido
- Institute of Biochemistry and Microbiology, Science Faculty, Universidad Austral de Chile, Valdivia, Chile
| | - Claudia Quezada
- Institute of Biochemistry and Microbiology, Science Faculty, Universidad Austral de Chile, Valdivia, Chile
| | - Rody San Martín
- Institute of Biochemistry and Microbiology, Science Faculty, Universidad Austral de Chile, Valdivia, Chile
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5
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van den Berg TNA, El Messaoudi S, Rongen GA, van den Broek PHH, Bilos A, Donders ART, Gomes ME, Riksen NP. Ticagrelor Does Not Inhibit Adenosine Transport at Relevant Concentrations: A Randomized Cross-Over Study in Healthy Subjects In Vivo. PLoS One 2015; 10:e0137560. [PMID: 26509673 PMCID: PMC4624811 DOI: 10.1371/journal.pone.0137560] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2015] [Accepted: 08/17/2015] [Indexed: 01/19/2023] Open
Abstract
BACKGROUND AND PURPOSE In patients with myocardial infarction, ticagrelor reduces cardiovascular and sepsis-related mortality, and can cause dyspnea. It is suggested that this is caused by adenosine receptor stimulation, because in preclinical studies, ticagrelor blocks the nucleoside transporter and increases cellular ATP release. We now investigated the effects of ticagrelor on the adenosine system in humans in vivo. EXPERIMENTAL APPROACH In a double-blinded, placebo-controlled cross-over trial in 14 healthy subjects, we have tested whether ticagrelor (180 mg) affects adenosine- and dipyridamole-induced forearm vasodilation, as surrogates of nucleoside uptake inhibition and adenosine formation, respectively. Also, ex vivo uptake of adenosine and uridine in isolated red blood cells was measured. Primary endpoint was adenosine-induced vasodilation. KEY RESULTS Ticagrelor did not affect adenosine- or dipyridamole-induced forearm vasodilation. Also, ex vivo uptake of adenosine and uridine in isolated red blood cells was not affected by ticagrelor. In vitro, ticagrelor dose-dependently inhibited nucleoside uptake, but only at supra-physiological concentrations. CONCLUSION AND IMPLICATIONS In conclusion, at relevant plasma concentration, ticagrelor does not affect adenosine transport, nor adenosine formation in healthy subjects. Therefore, it is unlikely that this mechanism is a relevant pleiotropic effect of ticagrelor. TRIAL REGISTRATION ClinicalTrials.gov NCT01996735.
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Affiliation(s)
- T. N. A. van den Berg
- Department of Pharmacology-Toxicology, Radboud university medical center, Nijmegen, The Netherlands
| | - S. El Messaoudi
- Department of Pharmacology-Toxicology, Radboud university medical center, Nijmegen, The Netherlands
| | - G. A. Rongen
- Department of Pharmacology-Toxicology, Radboud university medical center, Nijmegen, The Netherlands
- Department of Internal Medicine (division of vascular medicine), Radboud university medical center, Nijmegen, The Netherlands
| | - P. H. H. van den Broek
- Department of Pharmacology-Toxicology, Radboud university medical center, Nijmegen, The Netherlands
| | - A. Bilos
- Department of Pharmacology-Toxicology, Radboud university medical center, Nijmegen, The Netherlands
| | - A. R. T. Donders
- Department for Health Evidence, Radboud university medical center, Nijmegen, The Netherlands
| | - M. E. Gomes
- Department of Cardiology, Canisius Wilhelmina Hospital, Nijmegen, The Netherlands
| | - N. P. Riksen
- Department of Pharmacology-Toxicology, Radboud university medical center, Nijmegen, The Netherlands
- Department of Internal Medicine (division of vascular medicine), Radboud university medical center, Nijmegen, The Netherlands
- * E-mail:
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6
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Martí-Carvajal AJ, Solà I, Lathyris D. Homocysteine-lowering interventions for preventing cardiovascular events. Cochrane Database Syst Rev 2015; 1:CD006612. [PMID: 25590290 DOI: 10.1002/14651858.cd006612.pub4] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
BACKGROUND Cardiovascular disease, which includes coronary artery disease, stroke and congestive heart failure, is a leading cause of death worldwide. Homocysteine is an amino acid with biological functions in methionine metabolism. A postulated risk factor is an elevated circulating total homocysteine level, which is associated with cardiovascular events. The impact of homocysteine-lowering interventions, given to patients in the form of vitamins B6, B9 or B12 supplements, on cardiovascular events. This is an update of a review previously published in 2009 and 2013. OBJECTIVES To determine whether homocysteine-lowering interventions, provided in patients with and without pre-existing cardiovascular disease are effective in preventing cardiovascular events, as well as all-cause mortality and evaluate their safety. SEARCH METHODS We searched the Cochrane Central Register of Controlled Trials (CENTRAL 2014, Issue 1), MEDLINE (1950 to January week 5 2014), EMBASE (1980 to 2014 week 6) and LILACS (1986 to February 2014). We also searched Web of Science (1970 to 7 February 2014). We handsearched the reference lists of included papers. We also contacted researchers in the field. There was no language restriction in the search. SELECTION CRITERIA We included randomised controlled trials assessing the effects of homocysteine-lowering interventions for preventing cardiovascular events with a follow-up period of one year or longer. We considered myocardial infarction and stroke as the primary outcomes. We excluded studies in patients with end-stage renal disease. DATA COLLECTION AND ANALYSIS We performed study selection, 'Risk of bias' assessment and data extraction in duplicate. We estimated risk ratios (RR) for dichotomous outcomes. We measured statistical heterogeneity using the I(2) statistic. We used a random-effects model. MAIN RESULTS In this second updated Cochrane Review, we identified no new randomised controlled trials. Therefore, this new version includes 12 randomised controlled trials involving 47,429 participants. In general terms, 75% (9/12) trials had a low risk of bias. Homocysteine-lowering interventions compared with placebo did not significantly affect non-fatal or fatal myocardial infarction (1743/23,590 (7.38%) versus 1247/20,190 (6.17%); RR 1.02, 95% confidence interval (CI) 0.95 to 1.10, I(2) = 0%, high quality evidence), stroke (968/22,348 (4.33%) versus 974/18,957 (5.13%); RR 0.91, 95% CI 0.82 to 1.0, I(2) = 11%, high quality evidence) or death from any cause (2784/22,648 (12.29%) versus 2502/19,250 (10.64%); RR 1.01, 95% CI 0.96 to 1.07, I(2) = 6%, high quality evidence). Homocysteine-lowering interventions compared with placebo did not significantly affect serious adverse events (cancer) (1558/18,130 (8.59%) versus 1334/14,739 (9.05%); RR 1.06, 95% CI 0.98 to 1.13; I(2) = 0%, high quality evidence). AUTHORS' CONCLUSIONS This second update of this Cochrane Review found no evidence to suggest that homocysteine-lowering interventions in the form of supplements of vitamins B6, B9 or B12 given alone or in combination should be used for preventing cardiovascular events. Furthermore, there is no evidence to suggest that homocysteine-lowering interventions are associated with an increased risk of cancer.
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7
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Zanin RF, Bergamin LS, Braganhol E, Sévigny J, de Souza Wyse AT, Battastini AMO. Homocysteine modifies extracellular ATP availability in macrophages. Toxicol In Vitro 2013; 27:2273-8. [PMID: 24055814 DOI: 10.1016/j.tiv.2013.09.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2013] [Revised: 08/31/2013] [Accepted: 09/01/2013] [Indexed: 12/20/2022]
Abstract
Increased levels of plasma homocysteine (hyperhomocysteinemia-HHcy) are associated to the development of coronary artery disease (CAD), peripheral vascular disease and thrombosis. In addition, recent studies have shown that inflammation, probably mediated by macrophages, mediates the pathogenesis associated to high levels of homocysteine (Hcy). In the present study, we evaluated the Hcy effects in the ATP hydrolysis and its breakdown products in murine macrophages. The results showed that micromolar concentrations of Hcy increased the ATP, ADP and AMP hydrolysis. Additionally, our results show decreased inosine levels in the extracellular milieu of Hcy-exposed macrophages. The increasing in ATP, ADP and AMP hydrolysis are not explained by increased transcription or protein expression of NTPDases and ecto-5'-nucleotidase (ecto-5'-NT/CD73) enzymes. Moreover, the formation of reactive oxygen species did not interfere in the Hcy effects, which suggest that Hcy or Hcy metabolites act directly on the modulation of NTPDases and ecto-5'-NT/CD73 activities. In conclusion, Hcy induces the rapid breakdown of ATP, ADP and AMP to adenosine (ADO), which is classically known as an anti-inflammatory response in immune cells. However, by the action of these enzymes, the extracellular adenosine generated during Hcy treatment probably is uptaken into the cells, as evidenced by the decreased in inosine formation, and thus collaborating to the inflammatory complications associates to HHcy.
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Affiliation(s)
- Rafael Fernandes Zanin
- Programa de Pós-Graduação em Ciências Biológicas: Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul-UFRGS, Porto Alegre, RS, Brazil; Faculdade de Farmácia, Programa de Pós-Graduação em Biologia Celular e Molecular e Instituto de Toxicologia e Farmacologia, Pontifícia Universidade Católica do Rio Grande do Sul-PUCRS, Porto Alegre, RS, Brazil.
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8
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Martí-Carvajal AJ, Solà I, Lathyris D, Karakitsiou DE, Simancas-Racines D. Homocysteine-lowering interventions for preventing cardiovascular events. Cochrane Database Syst Rev 2013:CD006612. [PMID: 23440809 DOI: 10.1002/14651858.cd006612.pub3] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
BACKGROUND Cardiovascular disease (including coronary artery disease, stroke and congestive heart failure), is a leading cause of death worldwide. Homocysteine is an amino acid with biological functions in methionine metabolism. A postulated risk factor is elevated circulating total homocysteine levels, which are associated with cardiovascular events. This is an update of a review previously published in 2009. OBJECTIVES To assess the clinical effectiveness of homocysteine-lowering interventions in people with or without pre-existing cardiovascular disease. SEARCH METHODS We searched The Cochrane Central Register of Controlled Trials (CENTRAL) on The Cochrane Library (2012, Issue 2), MEDLINE (1950 to Feb week 2 2012), EMBASE (1980 to 2012 week 07), and LILACS (1986 to February 2012). We also searched ISI Web of Science (1970 to February 2012). We handsearched the reference lists of included papers. We also contacted researchers in the field. There was no language restriction in the search. SELECTION CRITERIA We included randomised controlled trials assessing the effects of homocysteine-lowering interventions for preventing cardiovascular events with a follow-up period of one year or longer. We considered myocardial infarction and stroke as the primary outcomes. We excluded studies in patients with end-stage renal disease. DATA COLLECTION AND ANALYSIS We performed study selection, 'Risk of bias' assessment and data extraction in duplicate. We estimated risk ratios (RR) for dichotomous outcomes. We measured statistical heterogeneity using I(2). We used a random-effects model. MAIN RESULTS In this updated systematic review, we identified four new randomised trials, resulting in a total of 12 randomised controlled trials involving 47,429 participants. In general terms, the trials had a low risk of bias. Homocysteine-lowering interventions compared with placebo did not significantly affect non-fatal or fatal myocardial infarction (pooled RR 1.02, 95% CI 0.95 to 1.10, I(2) = 0%), stroke (pooled RR 0.91, 95% CI 0.82 to 1.0, I(2) = 11%) or death by any cause (pooled RR 1.01 (95% CI 0.96 to 1.07, I(2): 6%)). Homocysteine-lowering interventions compared with placebo did not significantly affect serious adverse events (cancer) (1 RR 1.06, 95% CI 0.98 to 1.13; I(2) = 0%). AUTHORS' CONCLUSIONS This updated Cochrane review found no evidence to suggest that homocysteine-lowering interventions in the form of supplements of vitamins B6, B9 or B12 given alone or in combination should be used for preventing cardiovascular events. Furthermore, there is no evidence suggesting that homocysteine-lowering interventions are associated with an increased risk of cancer.
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Affiliation(s)
- Arturo J Martí-Carvajal
- Facultad de Ciencias de la Salud Eugenio Espejo, Universidad Tecnológica Equinoccial, Quito, Ecuador.
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9
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Abstract
Diabetic nephropathy ranks as the most devastating kidney disease worldwide. It characterizes in the early onset by glomerular hypertrophy, hyperfiltration and mesangial expansion. Experimental models show that overproduction of vascular endothelial growth factor (VEGF) is a pathogenic condition for podocytopathy; however the mechanisms that regulate this growth factor induction are not clearly identified. We determined that the adenosine A(2B) receptor (A(2B)AR) mediates VEGF overproduction in ex vivo glomeruli exposed to high glucose concentration, requiring PKCα and Erk1/2 activation. The glomerular content of A(2B)AR was concomitantly increased with VEGF at early stages of renal disease in streptozotocin-induced diabetic rats. Further, in vivo administration of an antagonist of A(2B)AR in diabetic rats blocked the glomerular overexpression of VEGF, mesangial cells activation and proteinuria. In addition, we also determined that the accumulation of extracellular adenosine occurs in glomeruli of diabetic rats. Correspondingly, raised urinary adenosine levels were found in diabetic rats. In conclusion, we evidenced that adenosine signaling at the onset of diabetic kidney disease is a pathogenic event that promotes VEGF induction.
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10
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Scherer EBS, Schmitz F, Vuaden FC, Savio LEB, Ferreira AGK, Tasca RAJC, Casali EA, Bogo MR, Bonan CD, Wyse ATS. Mild hyperhomocysteinemia alters extracellular adenine metabolism in rat brain. Neuroscience 2012; 223:28-34. [PMID: 22863571 DOI: 10.1016/j.neuroscience.2012.07.035] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2012] [Revised: 07/10/2012] [Accepted: 07/23/2012] [Indexed: 12/20/2022]
Abstract
Since homocysteine (Hcy) is considered a risk factor to cerebral diseases and adenine nucleotides are important molecules to brain normal function, in the present study we investigated the effect of chronic mild hyperhomocysteinemia on ectonucleotidase activities and expression in rat cerebral cortex. The levels of ATP, ADP, AMP and adenosine (Ado) in cerebrospinal fluid (CSF) of adult rats also were evaluated by high-performance liquid chromatography. For the chronic chemically induced mild hyperhomocysteinemia, Hcy (0.03 μmol/g of body weight) was administered subcutaneously from the 30th to the 60th day of life. Control rats received saline solution in the same volumes. Results showed that Hcy significantly decreased nucleotide hydrolysis in the synaptosomal fraction and increased E-NTPDase1 and ecto-5'-nucleotidase transcripts in rat cerebral cortex. ATP levels were significantly increased, while Ado decreased in CSF of Hcy-treated rats. These findings suggest that the unbalance in ATP and Ado levels may be, at last in part, involved in the cerebral toxicity of mild hyperhomocysteinemia.
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Affiliation(s)
- E B S Scherer
- Laboratório de Neuroproteção e Doenças Neurometabólicas, Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
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11
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Scherer EBS, Savio LEB, Vuaden FC, Ferreira AGK, Bogo MR, Bonan CD, Wyse ATS. Chronic mild hyperhomocysteinemia alters ectonucleotidase activities and gene expression of ecto-5'-nucleotidase/CD73 in rat lymphocytes. Mol Cell Biochem 2011; 362:187-94. [PMID: 22045065 DOI: 10.1007/s11010-011-1141-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2011] [Accepted: 10/22/2011] [Indexed: 12/20/2022]
Abstract
Since mild hyperhomocysteinemia is a risk factor for cardiovascular and cerebral diseases and extracellular nucleotides/nucleosides, which are controlled by the enzymatic action of ectonucleotidases, can induce an immune response, in the present study, we investigated the effect of chronic mild hyperhomocysteinemia on ectonucleotidase activities and expression in lymphocytes from mesenteric lymph nodes and serum of adult rats. For the chronic chemically induced mild hyperhomocysteinemia, Hcy (0.03 μmol/g of body weight) or saline (control) were administered subcutaneously from the 30th to the 60th day of life. Results showed that homocysteine significantly decreased ATP, ADP, and AMP hydrolysis in lymphocytes of adult rats. E-NTPDases transcriptions were not affected, while the ecto-5'-nucleotidase transcription was significantly decreased in mesenteric lymph nodes of hyperhomocysteinemic rats. ATP, ADP, and AMP hydrolysis were not affected by homocysteine in rat serum. Our findings suggest that Hcy in levels similar to considered risk factor to development of vascular diseases modulates the ectonucleotidases, which could lead to a pro-inflammatory status.
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Affiliation(s)
- Emilene B S Scherer
- Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
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12
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Böhmer AE, Brum LMP, Souza DG, Corrêa AMR, Oses JP, Viola GG, Saraiva PJ, Driemeier D, Portela LV, Souza DO. Chronic treatment with cyclosporine affects systemic purinergic parameters, homocysteine levels and vascular disturbances in rats. Chem Biol Interact 2010; 188:15-20. [PMID: 20599430 DOI: 10.1016/j.cbi.2010.06.011] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2010] [Revised: 06/17/2010] [Accepted: 06/22/2010] [Indexed: 11/25/2022]
Abstract
Vascular disease is a major cause of morbidity and mortality among transplanted recipients and cyclosporine (CsA) treatment has been consistently implicated in this event. In this study we assessed total blood homocysteine levels (tHcy), ecto-nucleotidase activities and adenine nucleotide/nucleoside levels searching for parameters related to the mechanisms of vascular damage induced by chronic CsA treatment in non-transplanted rats. Thirty male Wistar rats were divided in three groups: control group treated with corn oil, CsA 5mg/kg and CsA 15 mg/kg, administered by daily gastric gavage during 8 weeks. CsA 15 mg/kg treatment increased blood levels of tHcy. Both CsA treatments (5mg/kg and 15 mg/kg) decreased adenine nucleotides hydrolysis by ecto-nucleotidases in serum, which negatively correlated with tHcy levels (r: -0.74, r: -0.63 and r: -0.63, p<0.004, for ATP, ADP and AMP, respectively). CsA 15mg/kg induced a statistically significant increase in ADP and decrease in adenosine (ADO) plasma levels compared to control group. THcy levels were positively correlated with plasma ADP levels and negatively correlated with ADO levels (r: 0.84, p<0.0001 and r: -0.68, p<0.0001, respectively). Rats under CsA 15 mg/kg treatment presented cell injury and inflammatory responses in the endothelium and intima layer of the aorta artery. In conclusion, blood ecto-nucleotidases activity, tHcy, and ADP and ADO levels may be implicated in vascular injury induced by CsA treatment.
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Affiliation(s)
- Ana Elisa Böhmer
- Department of Biochemistry, ICBS, Federal University of Rio Grande do Sul, Avenida Ramiro Barcelos, 2600 Anexo, Porto Alegre 90035-003, RS, Brazil
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13
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Martí-Carvajal AJ, Solà I, Lathyris D, Salanti G. Homocysteine lowering interventions for preventing cardiovascular events. Cochrane Database Syst Rev 2009:CD006612. [PMID: 19821378 PMCID: PMC4164174 DOI: 10.1002/14651858.cd006612.pub2] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
BACKGROUND Cardiovascular disease such as coronary artery disease, stroke and congestive heart failure, is a leading cause of death worldwide. A postulated risk factor is elevated circulating total homocysteine (tHcy) levels which is influenced mainly by blood levels of cyanocobalamin (vitamin B12), folic acid (vitamin B9) and pyridoxine (vitamin B6). There is uncertainty regarding the strength of association between tHcy and the risk of cardiovascular disease. OBJECTIVES To assess the clinical effectiveness of homocysteine-lowering interventions (HLI) in people with or without pre-existing cardiovascular disease. SEARCH STRATEGY We searched The Cochrane Central Register of Controlled Trials (CENTRAL) on The Cochrane Library (issue 3 2008), MEDLINE (1950 to August 2008), EMBASE (1988 to August 2008), and LILACS (1982 to September 2, 2008). We also searched in Allied and Complementary Medicine (AMED; 1985 to August 2008), ISI Web of Science (1993 to August 2008), and the Cochrane Stroke Group Specialised Register (April 2007). We hand searched pertinent journals and the reference lists of included papers. We also contacted researchers in the field. There was no language restriction in the search. SELECTION CRITERIA We included randomised clinical trials (RCTs) assessing the effects of HLI for preventing cardiovascular events with a follow-up period of 1 year or longer. We considered myocardial infarction and stroke as the primary outcomes. We excluded studies in patients with end-stage renal disease. DATA COLLECTION AND ANALYSIS We independently performed study selection, risk of bias assessment and data extraction. We estimated relative risks (RR) for dichotomous outcomes. We measured statistical heterogeneity using I(2). We used a random-effects model to synthesise the findings. MAIN RESULTS We included eight RCTs involving 24,210 participants with a low risk of bias in general terms. HLI did not reduce the risk of non-fatal or fatal myocardial infarction, stroke, or death by any cause (pooled RR 1.03, 95% CI 0.94 to 1.13, I(2) = 0%; pooled RR 0.89, 95% CI 0.73 to 1.08, I(2) = 15%); and pooled RR 1.00 (95% CI 0.92 to 1.09, I(2): 0%), respectively. AUTHORS' CONCLUSIONS Results from available published trials suggest that there is no evidence to support the use of HLI to prevent cardiovascular events.
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Affiliation(s)
| | - Ivan Solà
- Iberoamerican Cochrane Centre, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain
| | | | - Georgia Salanti
- Clinical and Molecular Epidemiology Unit, Department of Hygiene and Epidemiology, University of Ioannina School of Medicine, Ioannina 45110, Greece
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Roa H, Gajardo C, Troncoso E, Fuentealba V, Escudero C, Yáñez A, Sobrevia L, Pastor-Anglada M, Quezada C, San Martin R. Adenosine mediates transforming growth factor-beta 1 release in kidney glomeruli of diabetic rats. FEBS Lett 2009; 583:3192-8. [PMID: 19737558 DOI: 10.1016/j.febslet.2009.09.003] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2009] [Revised: 08/18/2009] [Accepted: 09/02/2009] [Indexed: 01/13/2023]
Abstract
Up regulation of the transforming growth factor-beta 1 (TGF-beta1) axis has been recognized as a pathogenic event for progression of glomerulosclerosis in diabetic nephropathy. We demonstrate that glomeruli isolated from diabetic rats accumulate up to sixfold more extracellular adenosine than normal rats. Both decreased nucleoside uptake activity by the equilibrative nucleoside transporter 1 and increased AMP hydrolysis contribute to raise extracellular adenosine. Ex vivo assays indicate that activation of the low affinity adenosine A2B receptor subtype (A2BAR) mediates TGF-beta1 release from glomeruli of diabetic rats, a pathogenic event that could support progression of glomerulopathy when the bioavailability of adenosine is increased.
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Affiliation(s)
- H Roa
- Laboratorio Patología Molecular, Instituto de Bioquímica, Facultad de Ciencias, Universidad Austral de Chile, Valdivia, Chile
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Adenosine-A1 Receptors Activation Restores the Suppressed Cardioprotective Effects of Ischemic Preconditioning in Hyperhomocysteinemic Rat Hearts. J Cardiovasc Pharmacol 2009; 54:204-12. [DOI: 10.1097/fjc.0b013e3181b04cc5] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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16
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Manna C, Napoli D, Cacciapuoti G, Porcelli M, Zappia V. Olive oil phenolic compounds inhibit homocysteine-induced endothelial cell adhesion regardless of their different antioxidant activity. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2009; 57:3478-3482. [PMID: 19358606 DOI: 10.1021/jf8037659] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
In this study, we examine the effect of extra virgin olive oil phenolic compounds on homocysteine-induced endothelial dysfunction and whether the protective effects are related to their different scavenging activities. Structurally related compounds have been assayed for their ability to reduce homocysteine-induced monocyte adhesion as well as the cell surface expression of intercellular adhesion molecule-1 (ICAM-1) in EA.hy.926 cells. As well-known, among the selected phenolic compounds, hydroxytyrosol, homovanillyl alcohol, and the hydroxycinnamic acid derivatives caffeic and ferulic acid display high scavenging activities, while tyrosol and p-coumaric acid are poorly active. All of the tested compounds, approaching potential in vivo concentrations, significantly reduce homocysteine-induced cell adhesion and ICAM-1 expression. Interestingly, we report the first evidence that monophenols tyrosol and p-coumaric acid are selectively protective only in homocysteine-activated cells, while they are ineffective in reducing ICAM-1 expression induced by TNFalpha. Finally, we report the synergistic effect of o-diphenolic and monophenolic compounds.
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Affiliation(s)
- Caterina Manna
- Dipartimento di Biochimica e Biofisica F. Cedrangolo, Seconda Università di Napoli, Via De Crecchio no. 7, 80138 Naples, Italy.
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The 22G>A polymorphism in the adenosine deaminase gene impairs catalytic function but does not affect reactive hyperaemia in humans in vivo. Pharmacogenet Genomics 2008; 18:843-6. [DOI: 10.1097/fpc.0b013e328305e630] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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18
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Human in vivo research on the vascular effects of adenosine. Eur J Pharmacol 2008; 585:220-7. [DOI: 10.1016/j.ejphar.2008.01.053] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2007] [Revised: 12/21/2007] [Accepted: 01/22/2008] [Indexed: 11/19/2022]
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Dipyridamole enhances ischaemia-induced reactive hyperaemia by increased adenosine receptor stimulation. Br J Pharmacol 2008; 153:1169-76. [PMID: 18264130 DOI: 10.1038/bjp.2008.10] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
BACKGROUND AND PURPOSE Dipyridamole enhances post-occlusive reactive hyperaemia (PORH) in the human forearm vascular bed. We hypothesize that this effect is completely mediated by increased adenosine receptor stimulation. To test this hypothesis, the effect of caffeine (an adenosine receptor antagonist) on dipyridamole-induced augmentation of PORH was explored. EXPERIMENTAL APPROACH The forearm vasodilator responses to three increasing periods of forearm ischaemia (2, 5 and 13 min) were determined during placebo infusion. Forty minutes after the last reperfusion period, this procedure was repeated during intra-arterial infusion of dipyridamole (7.4 nmol min(-1) per 100 ml forearm). At least 2 weeks later, this whole procedure was repeated, but now in the presence of caffeine (90 microg min(-1) per 100 ml volume). KEY RESULTS After 2, 5 and 13 min of ischaemia, the average forearm blood flow increased to 5.6+/-0.7, 9.7+/-1.3 and 34.5+/-2.1 ml min(-1) per 100 ml. After infusion of dipyridamole into the brachial artery, these numbers were significantly increased to 7.7+/-0.8, 12.5+/-1.5 and 41.6+/-3.1 ml min(-1) per 100 ml. This response was abolished by the concomitant infusion of caffeine (6.6+/-0.5, 10.2+/-0.6, 35.1+/-2.2 (caffeine) versus 7.4+/-0.4, 10.5+/-0.6, 33.7+/-2.2 ml min(-1)per 100 ml (caffeine/dipyridamole)). CONCLUSIONS AND IMPLICATIONS Caffeine prevented the augmenting effect of dipyridamole on PORH. This indicates that dipyridamole-induced augmentation of PORH is mediated via increased adenosine receptor stimulation as a result of elevated extracellular formation of adenosine during ischaemia.
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20
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Cacciapuoti G, Manna C, Napoli D, Zappia V, Porcelli M. Homocysteine-induced endothelial cell adhesion is related to adenosine lowering and is not mediated byS-adenosylhomocysteine. FEBS Lett 2007; 581:4567-70. [PMID: 17850795 DOI: 10.1016/j.febslet.2007.08.042] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2007] [Revised: 08/02/2007] [Accepted: 08/03/2007] [Indexed: 11/24/2022]
Abstract
Hyperhomocysteinemia is a cardiovascular risk factor and may contribute to the pathogenesis of atherosclerosis by altering endothelial functions. The mechanism of homocysteine-induced cell adhesion has been here investigated using EA.hy 926 cells. Homocysteine induces a stereospecific, time- and dose-dependent cell adhesion which is prevented by adenosine. The dramatic increase of S-adenosylhomocysteine induced by adenosine-2',3'-dialdehyde does not cause cell adhesion, indicating that no apparent relationship exists between this process and intracellular S-adenosylhomocysteine content. Homocysteine-induced cell adhesion is abolished by pre-treatment with adenosine-2',3'-dialdehyde, demonstrating that the adenosine depletion caused by reversal of S-adenosylhomocysteine hydrolase reaction is responsible for homocysteine-induced cell damage.
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Affiliation(s)
- Giovanna Cacciapuoti
- Dipartimento di Biochimica e Biofisica, F. Cedrangolo, Seconda Università di Napoli, Naples, Italy.
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21
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Riksen NP, Franke B, van den Broek P, Smits P, Rongen GA. The 1976C>T polymorphism in the adenosine A2A receptor gene does not affect the vasodilator response to adenosine in humans in vivo. Pharmacogenet Genomics 2007; 17:551-4. [PMID: 17558310 DOI: 10.1097/fpc.0b013e32803fb78f] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The 1976C>T polymorphism in the adenosine A2A receptor gene (ADORA2A) modulates the psychological response to administration of the adenosine receptor antagonist caffeine. We quantified the vascular response to adenosine and caffeine to determine the relevance of this variant allele in the physiological response to these agents. We selected 10 study participants with the TT genotype and 10 CC controls, matched for activities of other proteins involved in the metabolism of adenosine. The vasodilator response to the intrabrachial administration of adenosine (0.5, 1.5, 5.0, 15.0, and 50.0 microg/min/dl; venous occlusion plethysmography) was not different between the groups (P=0.4). In addition, the effect of subsequent administration of caffeine (90 microg/min/dl) was not different (P=0.7). We conclude that the 1976C>T polymorphism does not affect the vascular response to adenosine and caffeine in humans in vivo. Therefore, this polymorphism does not contribute to the variation in the effects of adenosine receptor stimulation.
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Affiliation(s)
- Niels P Riksen
- Department of Pharmacology, Radboud University Nijmegen Medical Center, The Netherlands.
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22
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Riksen NP, Bosselaar M, Bakker SJL, Heine RJ, Rongen GA, Tack CJ, Smits P. Acute elevation of plasma non-esterified fatty acids increases pulse wave velocity and induces peripheral vasodilation in humans in vivo. Clin Sci (Lond) 2007; 113:33-40. [PMID: 17309447 DOI: 10.1042/cs20060365] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Plasma NEFA (non-esterified fatty acid) concentrations are elevated in patients with obesity. In the present study we first aimed to provide an integral haemodynamic profile of elevated plasma NEFAs by the simultaneous assessment of blood pressure, pulse wave velocity, FBF (forearm blood flow) and sympathetic nervous system activity during acute elevation of NEFAs. Secondly, we hypothesized that NEFA-induced vasodilation is mediated by adenosine receptor stimulation. In a randomized cross-over trial in healthy subjects, Intralipid® was infused for 2 h to elevate plasma NEFAs. Glycerol was administered as the Control infusion. We assessed blood pressure, pulse wave velocity, FBF (using venous occlusion plethysmography) and sympathetic nervous system activity by measurement of noradrenaline and adrenaline. During the last 15 min of Intralipid®/Control infusion, the adenosine receptor antagonist caffeine (90 μg·min−1·dl−1) was administered into the brachial artery of the non-dominant arm. Compared with Control infusion, Intralipid® increased pulse wave velocity, SBP (systolic blood pressure) and pulse pressure, as well as FBF (from 1.8±0.2 to 2.7±0.6 and from 2.3±0.2 to 2.7±0.6 ml·min−1·dl−1 for Intralipid® compared with Control infusion; P<0.05, n=9). Although in a positive control study caffeine attenuated adenosine-induced forearm vasodilation (P<0.01, n=6), caffeine had no effect on Intralipid®-induced vasodilation (P=0.5). In conclusion, elevation of plasma NEFA levels increased pulse wave velocity, SBP and pulse pressure. FBF was also increased, either by baroreflex-mediated inhibition of the sympathetic nervous system or by a direct vasodilating effect of NEFAs. As the adenosine receptor antagonist caffeine could not antagonize the vasodilator response, this response is not mediated by adenosine receptor stimulation.
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Affiliation(s)
- Niels P Riksen
- Department of Pharmacology-Toxicology, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands.
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Heil SG, Riksen NP, Boers GH, Smulders Y, Blom HJ. DNA methylation status is not impaired in treated cystathionine beta-synthase (CBS) deficient patients. Mol Genet Metab 2007; 91:55-60. [PMID: 17336565 DOI: 10.1016/j.ymgme.2007.01.008] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/14/2007] [Accepted: 01/15/2007] [Indexed: 11/23/2022]
Abstract
BACKGROUND Cystathionine beta-synthase (CBS) deficiency is an inborn error of metabolism that is biochemically characterized by severe hyperhomocysteinemia and homocystinuria. In tissues of mice deficient for CBS it has been demonstrated that global DNA methylation and DNA methylation of the H19 differentially methylated region (DMR) were impaired. In this study we aimed to investigate whether DNA methylation is disturbed in patients with hyperhomocysteinemia due to CBS-deficiency. METHODS Genomic DNA was isolated from heparin blood from nine CBS deficient patients that were treated with homomcysteine-lowering therapy and eight healthy controls. Global DNA methylation was measured by liquid chromatography-electrospay ionization-tandem mass spectrometry and gene-specific DNA methylation of the H19 DMR was determined by bisulphite-sequencing. RESULTS Homocysteine, AdoMet and AdoHcy levels were significantly elevated, whereas no differences in AdoMet:AdoHcy ratio were observed in plasma of treated CBS deficient patients compared with controls. Global DNA methylation and gene-specific DNA methylation of the H19 DMR was not different between CBS deficient patients and controls. CONCLUSION We demonstrate that DNA methylation is not impaired in treated CBS deficient patients. Further studies are necessary to investigate the precise role of homocysteine-lowering therapy in relation to DNA methylation in patients with homocystinuria.
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Affiliation(s)
- Sandra G Heil
- Laboratory of Pediatrics and Neurology, Radboud University Nijmegen Medical Centre, 6500 HB Nijmegen, The Netherlands.
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24
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Muñoz G, San Martín R, Farías M, Cea L, Vecchiola A, Casanello P, Sobrevia L. Insulin restores glucose inhibition of adenosine transport by increasing the expression and activity of the equilibrative nucleoside transporter 2 in human umbilical vein endothelium. J Cell Physiol 2007; 209:826-35. [PMID: 16924660 DOI: 10.1002/jcp.20769] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
L-Arginine transport and nitric oxide (NO) synthesis (L-arginine/NO pathway) are stimulated by insulin, adenosine or elevated extracellular D-glucose in human umbilical vein endothelial cells (HUVEC). Adenosine uptake via the human equilibrative nucleoside transporters 1 (hENT1) and 2 (hENT2) has been proposed as a mechanism regulating adenosine plasma concentration, and therefore its vascular effects in human umbilical veins. Thus, altered expression and/or activity of hENT1 or hENT2 could lead to abnormal physiological plasma adenosine level. We have characterized insulin effect on adenosine transport in HUVEC cultured in normal (5 mM) or high (25 mM) D-glucose. Insulin (1 nM) increased overall adenosine transport associated with higher hENT2-, but lower hENT1-mediated transport in normal D-glucose. Insulin increased hENT2 protein abundance in normal or high D-glucose, but reduced hENT1 protein abundance in normal D-glucose. Insulin did not alter the reduced hENT1 protein abundance, but blocked the reduced hENT1 and hENT2 mRNA expression induced by high D-glucose. Insulin effect on hENT1 mRNA expression in normal D-glucose was blocked by N(G)-nitro-L-arginine methyl ester (L-NAME, NO synthase inhibitor) and mimicked by S-nitroso-N-acetyl-L,D-penicillamine (SNAP, NO donor). L-NAME did not block insulin effect on hENT2 expression. In conclusion, insulin stimulation of overall adenosine transport results from increased hENT2 expression and activity via a NO-independent mechanism. These findings could be important in hyperglycemia-associated pathological pregnancies, such as gestational diabetes, where plasma adenosine removal by the endothelium is reduced, a condition that could alter the blood flow from the placenta to the fetus affecting fetus growth and development.
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Affiliation(s)
- Gonzalo Muñoz
- Cellular and Molecular Physiology Laboratory (CMPL), Medical Research Centre (CIM), Department of Obstetrics and Gynaecology, Faculty of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile
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25
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Tasatargil A, Sadan G, Karasu E, Ozdem S. Changes in Atrium and Thoracic Aorta Reactivity to Adenosinergic and Adrenergic Agonists in Experimental Hyperhomocysteinemia. J Cardiovasc Pharmacol 2006; 47:673-9. [PMID: 16775507 DOI: 10.1097/01.fjc.0000211756.31820.17] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
We prepared diet-induced hyperhomocysteinemia (hHcy) in adult male Wistar rats and investigated the effects of hHcy on the adenosinergic and adrenergic responses in vitro and in vivo. The responsiveness of right atria from hHcy rats to the negative chronotropic effects of adenosine (Ado) was found to be significantly greater in hHcy rats than in controls. The pD2 value and maximum effect of Ado were significantly increased in 12-week hHcy right atria when compared with those from age-matched controls. The vasodilatory effect of Ado on rat thoracic aorta was also increased in hHcy rats. In the presence of dipyridamole, an Ado uptake inhibitor, the negative chronotropic and vasodilatory effects of Ado were significantly potentiated in the hHcy rats much more than in the control rats. In anesthetized rats, Ado and dipyridamole, given as a rapid bolus into the femoral artery, led to reduction in mean blood pressure and heart rate. This effect was significantly pronounced in hHcy rats when compared with control animals. Otherwise, hHcy atria were found to have increased responsiveness to the positive chronotropic response to isoproterenol, an beta-adrenoceptor agonist. However, there were no significant differences between two groups in the vasoconstrictor effects to phenylephrine, an alpha-adrenoceptor agonist. On the basis of these results, we concluded that hHcy rats were significantly more sensitive to the negative chronotropic and vasorelaxant effects of Ado, possibly because of accelerated cellular Ado uptake and/or a change in Ado receptor-G protein system. This change may be related with the increased responsiveness to beta-adrenergic agonists in hHcy rats, and might contribute to the harmful cardiac effects of hHcy.
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Affiliation(s)
- Arda Tasatargil
- Department of Pharmacology, Akdeniz University Medical Faculty, Medical School, Akdeniz University, 07059, Antalya, Turkey.
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Invited Lectures : Overviews Purinergic signalling: past, present and future. Purinergic Signal 2006; 2:1-324. [PMID: 18404494 PMCID: PMC2096525 DOI: 10.1007/s11302-006-9006-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/02/2006] [Indexed: 12/11/2022] Open
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Böhmer AE, Pochmann D, Sarkis JJF. In vitro effect of homocysteine on nucleotide hydrolysis by blood serum from adult rats. Chem Biol Interact 2006; 160:159-64. [PMID: 16466706 DOI: 10.1016/j.cbi.2006.01.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2005] [Revised: 01/03/2006] [Accepted: 01/11/2006] [Indexed: 11/21/2022]
Abstract
During the past few years, elevated blood levels of homocysteine (Hcy) have been linked to increased risk of premature coronary artery disease, stroke and thromboembolism. These processes can be also related to the ratio adenine nucleotide/adenosine, since extracellularly these nucleotides are associated with modulation of processes such as platelet aggregation, vasodilatation and coronary flow. Furthermore, there are some studies that suggest a relationship between Hcy and plasma adenosine concentrations. The sequential hydrolysis of ATP to adenosine by soluble nucleotidases constitutes one of the systems for rapid inactivation of circulating adenine nucleotides. Thus, the main objective of this study was to evaluate if Hcy can participate in the modulation of the extracellular adenine nucleotide hydrolysis by rat blood serum. Our results showed that Hcy, at final concentrations of 5.0 mM, inhibits in vitro ATP, ADP and AMP hydrolysis by 26, 21 and 16%, respectively. Also Hcy, at final concentrations of 8.0mM, inhibited the in vitro hydrolysis of ATP, ADP and AMP by 46, 44 and 44%, respectively. Kinetic analysis showed that the inhibitions of the three adenine nucleotide hydrolyses in the presence of Hcy, by serum of adult rats, is of the uncompetitive type. The IC50 calculated from the results obtained were 6.52+/-1.75 mM (n = 4), 5.18 +/- 0.64 mM (n = 3) and 5.16 +/- 1.22 mM (n = 3) for ATP, ADP and AMP hydrolysis, respectively.
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Affiliation(s)
- Ana Elisa Böhmer
- Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Rua Ramiro Barcelos, 2600-Anexo, CEP 90035-003, Porto Alegre, RS, Brazil
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Riksen NP, Barrera P, van den Broek PHH, van Riel PLCM, Smits P, Rongen GA. Methotrexate modulates the kinetics of adenosine in humans in vivo. Ann Rheum Dis 2005; 65:465-70. [PMID: 16308339 PMCID: PMC1798086 DOI: 10.1136/ard.2005.048637] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
BACKGROUND Animal studies suggest that the anti-inflammatory effect of methotrexate (MTX) is mediated by increased adenosine concentrations. OBJECTIVE To assess the effect of MTX on the vasodilator effects of adenosine and the nucleoside uptake inhibitor, dipyridamole, in humans in vivo as a marker for changes in adenosine kinetics. METHODS Ten patients with active arthritis were treated with MTX (15 mg/week). Measurements were performed before and after 12 weeks of treatment. At these time points, the activity of adenosine deaminase was measured in isolated lymphocytes, and forearm blood flow (FBF) was determined by venous occlusion plethysmography during administration of adenosine and dipyridamole into the brachial artery. RESULTS The Vmax of adenosine deaminase in lymphocytes was reduced by MTX treatment (p<0.05). MTX significantly enhanced vasodilator response to adenosine (0.5 and 1.5 microg/min/dl of forearm tissue; mean (SE) FBF ratio increased from 1.2 (0.2) to 1.4 (0.2) and 2.2 (0.2) ml/dl/min, respectively, before and from 1.3 (0.1) to 1.8 (0.2) and 3.2 (0.5) ml/dl/min during MTX treatment; p<0.05). Also, dipyridamole-induced vasodilatation (30 and 100 microg/min/dl) was enhanced by MTX (FBF ratio increased from 1.2 (0.2) to 1.5 (0.3) and 1.8 (0.2), respectively, before and from 1.3 (0.1) to 1.8 (0.2) and 2.4 (0.4) during MTX treatment; p<0.05). CONCLUSIONS MTX treatment inhibits deamination of adenosine and potentiates adenosine-induced vasodilatation. Also dipyridamole-induced vasodilatation is enhanced by MTX treatment, suggesting an increased extracellular formation of adenosine. These effects on the adenosine kinetics in humans may contribute to the therapeutic efficacy of MTX.
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Affiliation(s)
- N P Riksen
- Department of Pharmacology-Toxicology 149, Radboud University Nijmegen Medical Centre, Geert Grooteplein 21, 6525 EZ Nijmegen, The Netherlands.
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Riksen NP, Rongen GA, Blom HJ, Boers GHJ, Smits P. Reduced adenosine receptor stimulation as a pathogenic factor in hyperhomocysteinemia. Clin Chem Lab Med 2005; 43:1001-6. [PMID: 16197288 DOI: 10.1515/cclm.2005.175] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
AbstractIn this review we discuss the hypothesis, and current evidence, that a decreased concentration of the endogenous purine-nucleoside adenosine contributes to the increased cardiovascular risk of patients with hyperhomocysteinemia. In hyperhomocysteinemia, the reaction equilibrium of the reaction catalysed by S-adenosylhomocysteine hydrolase will shift towards synthesis of S-adenosylhomocysteine, at the expense of free adenosine. Adenosine receptor stimulation induces several cardiovascular protective effects, such as vasodilation, inhibition of thrombocyte aggregation, of inflammation and of vascular smooth muscle cell proliferation. A decreased adenosine concentration could, therefore, well contribute to the cardiovascular complications of hyperhomocysteinemia. Previous animal studies have shown that administration of homocysteine decreases extracellular adenosine, associated with increased synthesis of S-adenosylhomocysteine. Recently, we showed that in patients with classical homocystinuria, cellular adenosine uptake is enhanced, thus limiting adenosine-induced vasodilation. These observations provide us with additional pharmacological targets, such as adenosine uptake inhibition, to reduce cardiovascular risk in patients with hyperhomocysteinemia.
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Affiliation(s)
- Niels P Riksen
- Department of Pharmacology-Toxicology, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands.
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