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Overgaard CB, Chan W, Chowdhary S, Zur RL, Wainstein R, Džavík V, Chan CT, Floras JS. Coronary and Systemic Vasodilator Responsiveness of Patients Receiving Conventional Intermittent or Nocturnal Hemodialysis. Hypertension 2024; 81:1996-2005. [PMID: 39041205 DOI: 10.1161/hypertensionaha.124.22790] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2024] [Accepted: 07/09/2024] [Indexed: 07/24/2024]
Abstract
BACKGROUND Nocturnal hemodialysis (nHD) restores the attenuated brachial artery vasodilator responsiveness of patients receiving conventional intermittent hemodialysis (iHD). Its impact on coronary vasodilatation is unknown. METHODS We evaluated 25 patients on hemodialysis who fulfilled transplant criteria: 15 on iHD (4-hour sessions, 3 d/wk) and 10 on nHD (≈40 h/wk over 8-10-hour sessions) plus 6 control participants. Following diagnostic angiography, left anterior descending (LAD) coronary flow reserve and mean luminal diameter were quantified at baseline and during sequential intracoronary administration of adenosine (infusion and bolus), nitroglycerin (bolus), acetylcholine (infusion), acetylcholine coinfused with vitamin C, and, finally, sublingual nitroglycerin. RESULTS Coronary flow reserve in those receiving nHD was augmented relative to iHD (3.28±0.26 versus 2.17±0.12 [mean±SEM]; P<0.03) but attenuated, relative to controls (4.80±0.63; P=0.011). Luminal dilatations induced by intracoronary adenosine and nitroglycerin were similar in nHD and controls but blunted in the iHD cohort (P<0.05 versus both). ACh elicited vasodilatation in controls but constriction in both dialysis groups (both P<0.05, versus control); vitamin C coinfusion had no effect. Sublingual nitroglycerin increased mid-left anterior descending diameter and reduced mean arterial pressure in controls (+15.2±2.68%; -16.00±1.60%) and in nHD recipients (+14.78±5.46%; -15.82±1.32%); iHD responses were markedly attenuated (+1.9±0.86%; -5.89±1.41%; P<0.05, all comparisons). CONCLUSIONS Coronary and systemic vasodilator responsiveness to both adenosine and nitroglycerin is augmented in patients receiving nHD relative to those receiving iHD, whereas vasoconstrictor responsiveness to acetylcholine does not differ. By improving coronary conduit and microvascular function, nHD may reduce the cardiovascular risk of patients on dialysis.
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Affiliation(s)
- Christopher B Overgaard
- Harold and Esther Mecklinger Family and the Posluns Family Cardiac Catheterization Research Laboratory, Mount Sinai Hospital, Toronto, ON, Canada (C.B.O., W.C., S.C., R.W., J.S.F.)
- University Health Network and Sinai Health Department of Medicine, Division of Cardiology (C.B.O., W.C., S.C., R.L.Z., R.W., V.D., C.T.C., J.S.F.)
- Peter Munk Cardiac Centre, University Health Network (C.B.O., W.C., S.C., R.L.Z., R.W., V.D., J.S.F.)
- Department of Medicine (C.B.O., W.C., S.C., R.L.Z., R.W., V.D., C.T.C., J.S.F.), University of Toronto, ON, Canada
| | - William Chan
- Harold and Esther Mecklinger Family and the Posluns Family Cardiac Catheterization Research Laboratory, Mount Sinai Hospital, Toronto, ON, Canada (C.B.O., W.C., S.C., R.W., J.S.F.)
- University Health Network and Sinai Health Department of Medicine, Division of Cardiology (C.B.O., W.C., S.C., R.L.Z., R.W., V.D., C.T.C., J.S.F.)
- Peter Munk Cardiac Centre, University Health Network (C.B.O., W.C., S.C., R.L.Z., R.W., V.D., J.S.F.)
- Department of Medicine (C.B.O., W.C., S.C., R.L.Z., R.W., V.D., C.T.C., J.S.F.), University of Toronto, ON, Canada
- Western Health, St. Albans, VIC, Australia (W.C.)
| | - Saqib Chowdhary
- Harold and Esther Mecklinger Family and the Posluns Family Cardiac Catheterization Research Laboratory, Mount Sinai Hospital, Toronto, ON, Canada (C.B.O., W.C., S.C., R.W., J.S.F.)
- University Health Network and Sinai Health Department of Medicine, Division of Cardiology (C.B.O., W.C., S.C., R.L.Z., R.W., V.D., C.T.C., J.S.F.)
- Peter Munk Cardiac Centre, University Health Network (C.B.O., W.C., S.C., R.L.Z., R.W., V.D., J.S.F.)
- Department of Medicine (C.B.O., W.C., S.C., R.L.Z., R.W., V.D., C.T.C., J.S.F.), University of Toronto, ON, Canada
- Manchester University NHS Foundation Trust, United Kingdom (S.C.)
| | - Rebecca L Zur
- University Health Network and Sinai Health Department of Medicine, Division of Cardiology (C.B.O., W.C., S.C., R.L.Z., R.W., V.D., C.T.C., J.S.F.)
- Peter Munk Cardiac Centre, University Health Network (C.B.O., W.C., S.C., R.L.Z., R.W., V.D., J.S.F.)
- Department of Medicine (C.B.O., W.C., S.C., R.L.Z., R.W., V.D., C.T.C., J.S.F.), University of Toronto, ON, Canada
- Department of Psychiatry (R.L.Z.), University of Toronto, ON, Canada
| | - Rodrigo Wainstein
- Harold and Esther Mecklinger Family and the Posluns Family Cardiac Catheterization Research Laboratory, Mount Sinai Hospital, Toronto, ON, Canada (C.B.O., W.C., S.C., R.W., J.S.F.)
- University Health Network and Sinai Health Department of Medicine, Division of Cardiology (C.B.O., W.C., S.C., R.L.Z., R.W., V.D., C.T.C., J.S.F.)
- Peter Munk Cardiac Centre, University Health Network (C.B.O., W.C., S.C., R.L.Z., R.W., V.D., J.S.F.)
- Department of Medicine (C.B.O., W.C., S.C., R.L.Z., R.W., V.D., C.T.C., J.S.F.), University of Toronto, ON, Canada
- Hospital de Clínicas de Porto Alegre, Federal University do Rio Grande do Sul, Brazil (R.W.)
| | - Vladimír Džavík
- University Health Network and Sinai Health Department of Medicine, Division of Cardiology (C.B.O., W.C., S.C., R.L.Z., R.W., V.D., C.T.C., J.S.F.)
- Peter Munk Cardiac Centre, University Health Network (C.B.O., W.C., S.C., R.L.Z., R.W., V.D., J.S.F.)
- Department of Medicine (C.B.O., W.C., S.C., R.L.Z., R.W., V.D., C.T.C., J.S.F.), University of Toronto, ON, Canada
| | - Christopher T Chan
- University Health Network and Sinai Health Department of Medicine, Division of Cardiology (C.B.O., W.C., S.C., R.L.Z., R.W., V.D., C.T.C., J.S.F.)
- Department of Medicine (C.B.O., W.C., S.C., R.L.Z., R.W., V.D., C.T.C., J.S.F.), University of Toronto, ON, Canada
| | - John S Floras
- Harold and Esther Mecklinger Family and the Posluns Family Cardiac Catheterization Research Laboratory, Mount Sinai Hospital, Toronto, ON, Canada (C.B.O., W.C., S.C., R.W., J.S.F.)
- University Health Network and Sinai Health Department of Medicine, Division of Cardiology (C.B.O., W.C., S.C., R.L.Z., R.W., V.D., C.T.C., J.S.F.)
- Peter Munk Cardiac Centre, University Health Network (C.B.O., W.C., S.C., R.L.Z., R.W., V.D., J.S.F.)
- Department of Medicine (C.B.O., W.C., S.C., R.L.Z., R.W., V.D., C.T.C., J.S.F.), University of Toronto, ON, Canada
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Seth J, Sharma S, Leong CJ, Rabkin SW. Eicosapentaenoic Acid (EPA) and Docosahexaenoic Acid (DHA) Ameliorate Heart Failure through Reductions in Oxidative Stress: A Systematic Review and Meta-Analysis. Antioxidants (Basel) 2024; 13:955. [PMID: 39199201 PMCID: PMC11351866 DOI: 10.3390/antiox13080955] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2024] [Revised: 07/31/2024] [Accepted: 08/02/2024] [Indexed: 09/01/2024] Open
Abstract
The objectives of this study were to explore the role that eicosapentaenoic acid (EPA) and/or docosahexaenoic acid (DHA) plays in heart failure (HF), highlighting the potential connection to oxidative stress pathways. Following PRISMA guidelines, we conducted electronic searches of the literature in MEDLINE and EMBASE focusing on serum EPA and/or DHA and EPA and/or DHA supplementation in adult patients with heart failure or who had heart failure as an outcome of this study. We screened 254 studies, encompassing RCTs, observational studies, and cohort studies that examined HF outcomes in relation to either serum concentrations or dietary supplementation of EPA and/or DHA. The exclusion criteria were pediatric patients, non-HF studies, abstracts, editorials, case reports, and reviews. Eleven studies met our criteria. In meta-analyses, high serum concentrations of DHA were associated with a lower rate of heart failure with a hazard ratio of 0.74 (CI = 0.59-0.94). High serum concentrations of EPA also were associated with an overall reduction in major adverse cardiovascular events with a hazard ratio of 0.60 (CI = 0.46-0.77). EPA and DHA, or n3-PUFA administration, were associated with an increased LVEF with a mean difference of 1.55 (CI = 0.07-3.03)%. A potential explanation for these findings is the ability of EPA and DHA to inhibit pathways by which oxidative stress damages the heart or impairs cardiac systolic or diastolic function producing heart failure. Specifically, EPA may lower oxidative stress within the heart by reducing the concentration of reactive oxygen species (ROS) within cardiac tissue by (i) upregulating nuclear factor erythroid 2-related factor 2 (Nrf2), which increases the expression of antioxidant enzyme activity, including heme oxygenase-1, thioredoxin reductase 1, ferritin light chain, ferritin heavy chain, and manganese superoxide dismutase (SOD), (ii) increasing the expression of copper-zinc superoxide dismutase (MnSOD) and glutathione peroxidase, (iii) targeting Free Fatty Acid Receptor 4 (Ffar4), (iv) upregulating expression of heme-oxygenase-1, (v) lowering arachidonic acid levels, and (vi) inhibiting the RhoA/ROCK signaling pathway. DHA may lower oxidative stress within the heart by (i) reducing levels of mitochondrial-fission-related protein DRP-1(ser-63), (ii) promoting the incorporation of cardiolipin within the mitochondrial membrane, (iii) reducing myocardial fibrosis, which leads to diastolic heart failure, (iv) reducing the expression of genes such as Appa, Myh7, and Agtr1α, and (v) reducing inflammatory cytokines such as IL-6, TNF-α. In conclusion, EPA and/or DHA have the potential to improve heart failure, perhaps mediated by their ability to modulate oxidative stress.
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Affiliation(s)
- Jayant Seth
- Faculty of Medicine, University of British Columbia, 9th Floor 2775 Laurel St., Vancouver, BC V5Z 1M9, Canada; (J.S.); (S.S.); (C.J.L.)
| | - Sohat Sharma
- Faculty of Medicine, University of British Columbia, 9th Floor 2775 Laurel St., Vancouver, BC V5Z 1M9, Canada; (J.S.); (S.S.); (C.J.L.)
| | - Cameron J. Leong
- Faculty of Medicine, University of British Columbia, 9th Floor 2775 Laurel St., Vancouver, BC V5Z 1M9, Canada; (J.S.); (S.S.); (C.J.L.)
| | - Simon W. Rabkin
- Faculty of Medicine, University of British Columbia, 9th Floor 2775 Laurel St., Vancouver, BC V5Z 1M9, Canada; (J.S.); (S.S.); (C.J.L.)
- Department of Medicine, Division of Cardiology, University of British Columbia, 9th Floor 2775 Laurel St., Vancouver, BC V5Z 1M9, Canada
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Hemilä H, de Man AME. Vitamin C deficiency can lead to pulmonary hypertension: a systematic review of case reports. BMC Pulm Med 2024; 24:140. [PMID: 38504249 PMCID: PMC10949735 DOI: 10.1186/s12890-024-02941-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2023] [Accepted: 03/01/2024] [Indexed: 03/21/2024] Open
Abstract
BACKGROUND In the early literature, unintentional vitamin C deficiency in humans was associated with heart failure. Experimental vitamin C deficiency in guinea pigs caused enlargement of the heart. The purpose of this study was to collect and analyze case reports on vitamin C and pulmonary hypertension. METHODS We searched Pubmed and Scopus for case studies in which vitamin C deficiency was considered to be the cause of pulmonary hypertension. We selected reports in which pulmonary hypertension was diagnosed by echocardiography or catheterization, for any age, sex, or dosage of vitamin C. We extracted quantitative data for our analysis. We used the mean pulmonary artery pressure (mPAP) as the outcome of primary interest. RESULTS We identified 32 case reports, 21 of which were published in the last 5 years. Dyspnea was reported in 69%, edema in 53% and fatigue in 28% of the patients. Vitamin C plasma levels, measured in 27 cases, were undetectable in 24 and very low in 3 cases. Diet was poor in 30 cases and 17 cases had neuropsychiatric disorders. Right ventricular enlargement was reported in 24 cases. During periods of vitamin C deficiency, the median mPAP was 48 mmHg (range 29-77 mmHg; N = 28). After the start of vitamin C administration, the median mPAP was 20 mmHg (range 12-33 mmHg; N = 18). For the latter 18 cases, mPAP was 2.4-fold (median) higher during vitamin C deficiency. Pulmonary vascular resistance (PVR) during vitamin C deficiency was reported for 9 cases, ranging from 4.1 to 41 Wood units. PVR was 9-fold (median; N = 5) higher during vitamin C deficiency than during vitamin C administration. In 8 cases, there was direct evidence that the cases were pulmonary artery hypertension (PAH). Probably the majority of the remaining cases were also PAH. CONCLUSIONS The cases analyzed in our study indicate that pulmonary hypertension can be one explanation for the reported heart failure of scurvy patients in the early literature. It would seem sensible to measure plasma vitamin C levels of patients with PH and examine the effects of vitamin C administration.
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Affiliation(s)
- Harri Hemilä
- Department of Public Health, University of Helsinki, POB 41, Helsinki, FI-00014, Finland.
| | - Angelique M E de Man
- Department of Intensive Care Medicine, Amsterdam University Medical Centers, location VUmc, Amsterdam, The Netherlands.
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Reid MB. Redox Implications of Extreme Task Performance: The Case in Driver Athletes. Cells 2022; 11:cells11050899. [PMID: 35269521 PMCID: PMC8909750 DOI: 10.3390/cells11050899] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Revised: 02/26/2022] [Accepted: 03/03/2022] [Indexed: 02/04/2023] Open
Abstract
Redox homeostasis and redox-mediated signaling mechanisms are fundamental elements of human biology. Physiological levels of reactive oxygen species (ROS) and reactive nitrogen species (RNS) modulate a range of functional processes at the cellular, tissue, and systemic levels in healthy humans. Conversely, excess ROS or RNS activity can disrupt function, impairing the performance of daily activities. This article analyzes the impact of redox mechanisms on extreme task performance. Such activities (a) require complex motor skills, (b) are physically demanding, (c) are performed in an extreme environment, (d) require high-level executive function, and (e) pose an imminent risk of injury or death. The current analysis utilizes race car driving as a representative example. The physiological challenges of this extreme task include physical exertion, g loading, vibration, heat exposure, dehydration, noise, mental demands, and emotional factors. Each of these challenges stimulates ROS signaling, RNS signaling, or both, alters redox homeostasis, and exerts pro-oxidant effects at either the tissue or systemic levels. These redox mechanisms appear to promote physiological stress during race car driving and impair the performance of driver athletes.
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Affiliation(s)
- Michael B Reid
- College of Health and Human Performance, University of Florida, Gainesville, FL 32611, USA
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Emadi N, Nemati MH, Ghorbani M, Allahyari E. The Effect of High-Dose Vitamin C on Biochemical Markers of Myocardial Injury in Coronary Artery Bypass Surgery. Braz J Cardiovasc Surg 2019; 34:517-524. [PMID: 31719005 PMCID: PMC6852463 DOI: 10.21470/1678-9741-2018-0312] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
OBJECTIVE To evaluate the effect of high-dose vitamin C on cardiac reperfusion injury and plasma levels of creatine kinase-muscle/brain (CK-MB), troponin I, and lactate dehydrogenase (LDH) in patients undergoing coronary artery bypass grafting (CABG). METHODS This is a double-blind randomized clinical trial study. Fifty patients (50-80 years old) who had CABG surgery were selected. The intervention group received 5 g of intravenous vitamin C before anesthesia induction and 5 g of vitamin C in cardioplegic solution. The control group received the same amount of placebo (normal saline). Arterial blood samples were taken to determine the serum levels of CK-MB, troponin I, and LDH enzymes. Left ventricular ejection fraction was measured and hemodynamic parameters were recorded at intervals. RESULTS High doses of vitamin C in the treatment group led to improvement of ventricular function (ejection fraction [EF]) and low Intensive Care Unit (ICU) stay. The cardiac enzymes level in the vitamin C group was lower than in the control group. These changes were not significant between the groups in different time intervals (anesthesia induction, end of bypass, 6 h after surgery, and 24 h after surgery) for CK-MB, LDH, and troponin I. Hemodynamic parameters, hematocrit, potassium, urinary output, blood transfusion, arrhythmia, and inotropic support showed no significant difference between the groups. CONCLUSION Vitamin C has significantly improved the patients' ventricular function (EF) 72 h after surgery and reduced the length of ICU stay. No significant changes in cardiac biomarkers, including CK-MB, troponin I, and LDH, were seen over time in each group. IRCT CODE IRCT2016053019470N33.
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Affiliation(s)
- Nafiseh Emadi
- Shiraz University of Medical Sciences Blood Circulation Technology Shiraz Iran Blood Circulation Technology, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Mohammad Hasan Nemati
- Shiraz University of Medical Sciences Department of Heart Surgery Shiraz Iran Department of Heart Surgery, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Mohammad Ghorbani
- Shiraz University of Medical Sciences Anesthesiology Research Center Shiraz Iran Anesthesiology Research Center, Shiraz University of Medical Sciences, Shiraz, Iran.,Torbat Heydarieh University of Medical Sciences Department of Public Health Torbat Heydarieh Iran Department of Public Health, Torbat Heydarieh University of Medical Sciences, Torbat Heydarieh, Iran
| | - Elahe Allahyari
- Shiraz University of Medical Sciences Department of Anesthesiology Shiraz Iran Department of Anesthesiology, Shiraz University of Medical Sciences, Shiraz, Iran
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Adrenergic Agonists Bind to Adrenergic-Receptor-Like Regions of the Mu Opioid Receptor, Enhancing Morphine and Methionine-Enkephalin Binding: A New Approach to "Biased Opioids"? Int J Mol Sci 2018; 19:ijms19010272. [PMID: 29342106 PMCID: PMC5796218 DOI: 10.3390/ijms19010272] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Revised: 01/10/2018] [Accepted: 01/13/2018] [Indexed: 11/16/2022] Open
Abstract
Extensive evidence demonstrates functional interactions between the adrenergic and opioid systems in a diversity of tissues and organs. While some effects are due to receptor and second messenger cross-talk, recent research has revealed an extracellular, allosteric opioid binding site on adrenergic receptors that enhances adrenergic activity and its duration. The present research addresses whether opioid receptors may have an equivalent extracellular, allosteric adrenergic binding site that has similar enhancing effects on opioid binding. Comparison of adrenergic and opioid receptor sequences revealed that these receptors share very significant regions of similarity, particularly in some of the extracellular and transmembrane regions associated with adrenergic binding in the adrenergic receptors. Five of these shared regions from the mu opioid receptor (muOPR) were synthesized as peptides and tested for binding to adrenergic, opioid and control compounds using ultraviolet spectroscopy. Adrenergic compounds bound to several of these muOPR peptides with low micromolar affinity while acetylcholine, histamine and various adrenergic antagonists did not. Similar studies were then conducted with purified, intact muOPR with similar results. Combinations of epinephrine with methionine enkephalin or morphine increased the binding of both by about half a log unit. These results suggest that muOPR may be allosterically enhanced by adrenergic agonists.
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Pergolizzi B, Carriero V, Abbadessa G, Penna C, Berchialla P, De Francia S, Bracco E, Racca S. Subchronic nandrolone administration reduces cardiac oxidative markers during restraint stress by modulating protein expression patterns. Mol Cell Biochem 2017; 434:51-60. [DOI: 10.1007/s11010-017-3036-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Accepted: 04/12/2017] [Indexed: 01/20/2023]
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Davis JL, Paris HL, Beals JW, Binns SE, Giordano GR, Scalzo RL, Schweder MM, Blair E, Bell C. Liposomal-encapsulated Ascorbic Acid: Influence on Vitamin C Bioavailability and Capacity to Protect Against Ischemia-Reperfusion Injury. Nutr Metab Insights 2016; 9:25-30. [PMID: 27375360 PMCID: PMC4915787 DOI: 10.4137/nmi.s39764] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Revised: 04/27/2016] [Accepted: 04/29/2016] [Indexed: 12/12/2022] Open
Abstract
Intravenous administration of vitamin C has been shown to decrease oxidative stress and, in some instances, improve physiological function in adult humans. Oral vitamin C administration is typically less effective than intravenous, due in part to inferior vitamin C bioavailability. The purpose of this study was to determine the efficacy of oral delivery of vitamin C encapsulated in liposomes. On 4 separate randomly ordered occasions, 11 men and women were administered an oral placebo, or 4 g of vitamin C via oral, oral liposomal, or intravenous delivery. The data indicate that oral delivery of 4 g of vitamin C encapsulated in liposomes (1) produces circulating concentrations of vitamin C that are greater than unencapsulated oral but less than intravenous administration and (2) provides protection from ischemia–reperfusion-mediated oxidative stress that is similar to the protection provided by unencapsulated oral and intravenous administrations.
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Affiliation(s)
- Janelle L Davis
- Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, USA
| | - Hunter L Paris
- Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, USA
| | - Joseph W Beals
- Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, USA
| | - Scott E Binns
- Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, USA
| | - Gregory R Giordano
- Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, USA
| | - Rebecca L Scalzo
- Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, USA
| | - Melani M Schweder
- Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, USA
| | - Emek Blair
- Empirical Labs, Fort Collins, Colorado, USA.; Nutritional Biomimetics LLC, Fort Collins, Colorado, USA.; Present address: Valimenta Labs, Fort Collins, Colorado, USA
| | - Christopher Bell
- Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, USA
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Zabet MH, Mohammadi M, Ramezani M, Khalili H. Effect of high-dose Ascorbic acid on vasopressor's requirement in septic shock. J Res Pharm Pract 2016; 5:94-100. [PMID: 27162802 PMCID: PMC4843590 DOI: 10.4103/2279-042x.179569] [Citation(s) in RCA: 180] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Objective: Effects of ascorbic acid on hemodynamic parameters of septic shock were evaluated in nonsurgical critically ill patients in limited previous studies. In this study, the effect of high-dose ascorbic acid on vasopressor drug requirement was evaluated in surgical critically ill patients with septic shock. Methods: Patients with septic shock who required a vasopressor drug to maintain mean arterial pressure >65 mmHg were assigned to receive either 25 mg/kg intravenous ascorbic acid every 6 h or matching placebo for 72 h. Vasopressor dose and duration were considered as the primary outcomes. Duration of Intensive Care Unit (ICU) stay and 28-day mortality has been defined as secondary outcomes. Findings: During the study period, 28 patients (14 in each group) completed the trial. Mean dose of norepinephrine during the study period (7.44 ± 3.65 vs. 13.79 ± 6.48 mcg/min, P = 0.004) and duration of norepinephrine administration (49.64 ± 25.67 vs. 71.57 ± 1.60 h, P = 0.007) were significantly lower in the ascorbic acid than the placebo group. No statistically significant difference was detected between the groups regarding the length of ICU stay. However, 28-day mortality was significantly lower in the ascorbic acid than the placebo group (14.28% vs. 64.28%, respectively; P = 0.009). Conclusion: High-dose ascorbic acid may be considered as an effective and safe adjuvant therapy in surgical critically ill patients with septic shock. The most effective dose of ascorbic acid and the best time for its administration should be determined in future studies.
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Affiliation(s)
| | - Mostafa Mohammadi
- Department of Intensive Care Unit, Imam Khomeini Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | - Masoud Ramezani
- Department of Intensive Care Unit, Imam Khomeini Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | - Hossein Khalili
- Department of Clinical Pharmacy, Tehran University of Medical Sciences, Tehran, Iran
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Root-Bernstein R, Dillon PF. A common molecular motif characterizes extracellular allosteric enhancers of GPCR aminergic receptors and suggests enhancer mechanism of action. Curr Med Chem 2015; 21:3673-86. [PMID: 25174918 PMCID: PMC4266041 DOI: 10.2174/0929867321666140826120604] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2013] [Revised: 04/08/2014] [Accepted: 08/22/2014] [Indexed: 11/22/2022]
Abstract
Several classes of compounds that have no intrinsic activity on aminergic systems nonetheless enhance the potency of aminergic receptor ligands three-fold or more while significantly increasing their duration of activity, preventing tachyphylaxis and reversing fade. Enhancer compounds include ascorbic acid, ethylenediaminetetraacetic acid, cortico-steroids, opioid peptides, opiates and opiate antagonists. This paper provides the first review of aminergic enhancement, demonstrating that all enhancers have a common, inobvious molecular motif and work through a common mechanism that is manifested by three common characteristics. First, aminergic enhancers bind directly to the amines they enhance, suggesting that the common structural motif is reflected in common binding targets. Second, one common target is the first extracellular loop of aminergic receptors. Third, at least some enhancers are antiphosphodiesterases. These observations suggest that aminergic enhancers act on the extracellular surface of aminergic receptors to keep the receptor in its high affinity state, trapping the ligand inside the receptor. Enhancer binding produces allosteric modifications of the receptor structure that interfere with phosphorylation of the receptor, thereby inhibiting down-regulation of the receptor. The mechanism explains how enhancers potentiate aminergic activity and increase duration of activity and makes testable predictions about additional compounds that should act as aminergic enhancers.
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Affiliation(s)
| | - Patrick F Dillon
- Department of Physiology, Michigan State University, East Lansing, MI 48824 USA.
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11
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Novel aspects of ROS signalling in heart failure. Basic Res Cardiol 2013; 108:359. [PMID: 23740217 DOI: 10.1007/s00395-013-0359-8] [Citation(s) in RCA: 119] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2013] [Revised: 05/03/2013] [Accepted: 05/05/2013] [Indexed: 12/20/2022]
Abstract
Heart failure and many of the conditions that predispose to heart failure are associated with oxidative stress. This is considered to be important in the pathophysiology of the condition but clinical trials of antioxidant approaches to prevent cardiovascular morbidity and mortality have been unsuccessful. Part of the reason for this may be the failure to appreciate the complexity of the effects of reactive oxygen species. At one extreme, excessive oxidative stress damages membranes, proteins and DNA but lower levels of reactive oxygen species may exert much more subtle and specific regulatory effects (termed redox signalling), even on physiological signalling pathways. In this article, we review our current understanding of the roles of such redox signalling pathways in the pathophysiology of heart failure, including effects on cardiomyocyte hypertrophy signalling, excitation-contraction coupling, arrhythmia, cell viability and energetics. Reactive oxygen species generated by NADPH oxidase proteins appear to be especially important in redox signalling. The delineation of specific redox-sensitive pathways and mechanisms that contribute to different components of the failing heart phenotype may facilitate the development of newer targeted therapies as opposed to the failed general antioxidant approaches of the past.
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Perjés Á, Kubin A, Kónyi A, Szabados S, Cziráki A, Skoumal R, Ruskoaho H, Szokodi I. Physiological regulation of cardiac contractility by endogenous reactive oxygen species. Acta Physiol (Oxf) 2012; 205:26-40. [PMID: 22463609 DOI: 10.1111/j.1748-1716.2012.02391.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Increased production of reactive oxygen species (ROS) has been linked to the pathogenesis of congestive heart failure. However, emerging evidence suggests the involvement of ROS in the regulation of various physiological cellular processes in the myocardium. In this review, we summarize the latest findings regarding the role of ROS in the acute regulation of cardiac contractility. We discuss ROS-dependent modulation of the inotropic responses to G protein-coupled receptor agonists (e.g. β-adrenergic receptor agonists and endothelin-1), the potential cellular sources of ROS (e.g. NAD(P)H oxidases and mitochondria) and the proposed end-targets and signalling pathways by which ROS affect contractility. Accumulating new data supports the fundamental role of endogenously generated ROS to regulate cardiac function under physiological conditions.
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Affiliation(s)
| | - A.M. Kubin
- Department of Pharmacology and Toxicology; Institute of Biomedicine; Biocenter Oulu; University of Oulu; Oulu; Finland
| | - A. Kónyi
- Heart Institute; Medical School; University of Pécs; Pécs; Hungary
| | - S. Szabados
- Heart Institute; Medical School; University of Pécs; Pécs; Hungary
| | - A. Cziráki
- Heart Institute; Medical School; University of Pécs; Pécs; Hungary
| | - R. Skoumal
- Department of Pharmacology and Toxicology; Institute of Biomedicine; Biocenter Oulu; University of Oulu; Oulu; Finland
| | - H. Ruskoaho
- Department of Pharmacology and Toxicology; Institute of Biomedicine; Biocenter Oulu; University of Oulu; Oulu; Finland
| | - I. Szokodi
- Heart Institute; Medical School; University of Pécs; Pécs; Hungary
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Mak S, Van Spall HG, Wainstein RV, Sasson Z. Strain, Strain Rate, and the Force Frequency Relationship in Patients with and without Heart Failure. J Am Soc Echocardiogr 2012; 25:341-8. [DOI: 10.1016/j.echo.2011.11.008] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/14/2011] [Indexed: 10/14/2022]
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Perjés Á, Kubin A, Kónyi A, Szabados S, Cziráki A, Skoumal R, Ruskoaho H, Szokodi I. Physiological regulation of cardiac contractility by endogenous reactive oxygen species. Acta Physiol (Oxf) 2012. [DOI: 10.1111/j.1748-1716.2011.02391.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
| | - A.M. Kubin
- Department of Pharmacology and Toxicology; Institute of Biomedicine; Biocenter Oulu; University of Oulu; Oulu; Finland
| | - A. Kónyi
- Heart Institute; Medical School; University of Pécs; Pécs; Hungary
| | - S. Szabados
- Heart Institute; Medical School; University of Pécs; Pécs; Hungary
| | - A. Cziráki
- Heart Institute; Medical School; University of Pécs; Pécs; Hungary
| | - R. Skoumal
- Department of Pharmacology and Toxicology; Institute of Biomedicine; Biocenter Oulu; University of Oulu; Oulu; Finland
| | - H. Ruskoaho
- Department of Pharmacology and Toxicology; Institute of Biomedicine; Biocenter Oulu; University of Oulu; Oulu; Finland
| | - I. Szokodi
- Heart Institute; Medical School; University of Pécs; Pécs; Hungary
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Thorstensen A, Dalen H, Amundsen BH, Støylen A. Peak systolic velocity indices are more sensitive than end-systolic indices in detecting contraction changes assessed by echocardiography in young healthy humans. ACTA ACUST UNITED AC 2011; 12:924-30. [DOI: 10.1093/ejechocard/jer178] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Richards JC, Lonac MC, Johnson TK, Schweder MM, Bell C. Epigallocatechin-3-gallate increases maximal oxygen uptake in adult humans. Med Sci Sports Exerc 2011; 42:739-44. [PMID: 19952844 DOI: 10.1249/mss.0b013e3181bcab6c] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
UNLABELLED Epigallocatechin-3-gallate (EGCG), a component of green tea, increases endurance performance in animals and promotes fat oxidation during cycle ergometer exercise in adult humans. PURPOSE We have investigated the hypothesis that short-term consumption of EGCG delays the onset of the ventilatory threshold (VT) and increases maximal oxygen uptake (VO2max). METHODS In this randomized, repeated-measures, double-blind study, 19 healthy adults (11 males and 8 females, age = 26 ± 2 yr (mean ± SE)) received seven placebo or seven EGCG (135-mg) pills. Forty-eight hours before data collection, participants began consuming three pills per day; the last pill was taken 2 h before exercise testing. VT and VO2max were determined from breath-by-breath indirect calorimetry data collected during continuous incremental stationary cycle ergometer exercise (20-35 W·min(-1)), from rest until volitional fatigue. Each condition/exercise test was separated by a minimum of 14 d. RESULTS Compared with placebo, short-term EGCG consumption increased VO2max (3.123 ± 0.187 vs 3.259 ± 0.196 L·min(-1), P = 0.04). Maximal work rate (301 ± 15 vs 301 ± 16 W, P = 0.98), maximal RER (1.21 ± 0.01 vs 1.22 ± 0.02, P = 0.27), and maximal HR were unaffected (180 ± 3 vs 180 ± 3 beats·min(-1), P = 0.87). In a subset of subjects (n = 11), maximal cardiac output (determined via open-circuit acetylene breathing) was also unaffected by EGCG (29.6 ± 2.2 vs 30.2 ± 1.4 L·min(-1), P = 0.70). Contrary to our hypothesis, EGCG decreased VO2 at VT (1.57 ± 0.11 vs 1.48 ± 0.10 L·min(-1)), but this change was not significant (P = 0.06). CONCLUSIONS Short-term consumption of EGCG increased VO2max without affecting maximal cardiac output, suggesting that EGCG may increase arterial-venous oxygen difference.
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Affiliation(s)
- Jennifer C Richards
- Department of Health and Exercise Science, Colorado State University, Fort Collins, CO 80523-1582, USA
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Kubin AM, Skoumal R, Tavi P, Kónyi A, Perjés A, Leskinen H, Ruskoaho H, Szokodi I. Role of reactive oxygen species in the regulation of cardiac contractility. J Mol Cell Cardiol 2011; 50:884-93. [PMID: 21320508 DOI: 10.1016/j.yjmcc.2011.02.005] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/08/2010] [Revised: 02/03/2011] [Accepted: 02/03/2011] [Indexed: 01/12/2023]
Abstract
Increased production of reactive oxygen species (ROS) has been linked to the pathogenesis of contractile dysfunction in heart failure. However, it is unclear whether ROS can regulate physiological cellular processes in the myocardium. Here, we characterized the role of endogenous ROS production in the acute regulation of cardiac contractility in the intact rat heart. In isolated perfused rat hearts, endothelin-1 (ET-1, 1nmol/L) stimulated ROS formation in the left ventricle, which was prevented by the antioxidant N-acetylcysteine and the NAD(P)H oxidase inhibitor apocynin. N-acetylcysteine, the superoxide dismutase mimetic MnTMPyP, and apocynin significantly attenuated ET-1-mediated inotropic effect, which was accompanied by inhibition of extracellular signal regulated kinase 1/2 (ERK1/2) phosphorylation. Moreover, the mitochondrial K(ATP) channel blocker 5-HD, and the mitochondrial large conductance calcium activated potassium channel blocker paxilline, but not the sarcolemmal K(ATP) channel blocker HMR 1098 attenuated the inotropic response to ET-1. However, ET-1-induced ROS generation was not abolished by inhibiting mitochondrial K(ATP) channel opening. In contrast to ET-1 stimulation, the positive inotropic effect of β(1)-adrenergic receptor agonist dobutamine (250nmol/L) was significantly augmented by N-acetylcysteine and apocynin. Moreover, dobutamine-induced phospholamban phosphorylation was markedly enhanced by apocynin. In conclusion, NAD(P)H oxidase-derived ROS play a physiological role in the acute regulation of cardiac contractility in the intact rat heart. Our results reveal that ET-1-induced increase in cardiac contractility is partially dependent on enhanced ROS generation, which in turn, activates the ERK1/2 pathway. On the other hand, β-adrenergic receptor-induced positive inotropic effect and phospholamban phosphorylation is enhanced by NAD(P)H oxidase inhibition.
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Affiliation(s)
- Anna-Maria Kubin
- Institute of Biomedicine, Department of Pharmacology and Toxicology, Biocenter Oulu, University of Oulu, Oulu, Finland
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Dillon PF, Root-Bernstein R, Robinson NE, Abraham WM, Berney C. Receptor-mediated enhancement of beta adrenergic drug activity by ascorbate in vitro and in vivo. PLoS One 2010; 5:e15130. [PMID: 21179213 PMCID: PMC3001466 DOI: 10.1371/journal.pone.0015130] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2010] [Accepted: 10/25/2010] [Indexed: 11/25/2022] Open
Abstract
Rationale Previous in vitro research demonstrated that ascorbate enhances potency and duration of activity of agonists binding to alpha 1 adrenergic and histamine receptors. Objectives Extending this work to beta 2 adrenergic systems in vitro and in vivo. Methods Ultraviolet spectroscopy was used to study ascorbate binding to adrenergic receptor preparations and peptides. Force transduction studies on acetylcholine-contracted trachealis preparations from pigs and guinea pigs measured the effect of ascorbate on relaxation due to submaximal doses of beta adrenergic agonists. The effect of inhaled albuterol with and without ascorbate was tested on horses with heaves and sheep with carbachol-induced bronchoconstriction. Measurements Binding constants for ascorbate binding to beta adrenergic receptor were derived from concentration-dependent spectral shifts. Dose- dependence curves were obtained for the relaxation of pre-contracted trachealis preparations due to beta agonists in the presence and absence of varied ascorbate. Tachyphylaxis and fade were also measured. Dose response curves were determined for the effect of albuterol plus-and-minus ascorbate on airway resistance in horses and sheep. Main Results Ascorbate binds to the beta 2 adrenergic receptor at physiological concentrations. The receptor recycles dehydroascorbate. Physiological and supra-physiological concentrations of ascorbate enhance submaximal epinephrine and isoproterenol relaxation of trachealis, producing a 3–10-fold increase in sensitivity, preventing tachyphylaxis, and reversing fade. In vivo, ascorbate improves albuterol's effect on heaves and produces a 10-fold enhancement of albuterol activity in “asthmatic” sheep. Conclusions Ascorbate enhances beta-adrenergic activity via a novel receptor-mediated mechanism; increases potency and duration of beta adrenergic agonists effective in asthma and COPD; prevents tachyphylaxis; and reverses fade. These novel effects are probably caused by a novel mechanism involving phosphorylation of aminergic receptors and have clinical and drug-development applications.
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Affiliation(s)
- Patrick F. Dillon
- Department of Physiology, Michigan State University, East Lansing, Michigan, United States of America
| | - Robert Root-Bernstein
- Department of Physiology, Michigan State University, East Lansing, Michigan, United States of America
- * E-mail:
| | - N. Edward Robinson
- Department of Large Animal Clinical Science, Michigan State University, East Lansing, Michigan, United States of America
| | - William M. Abraham
- Department of Research, Mount Sinai Medical Center, Miami Beach, Florida, United States of America
| | - Catherine Berney
- Department of Large Animal Clinical Science, Michigan State University, East Lansing, Michigan, United States of America
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Dunn SP, Bleske B, Dorsch M, Macaulay T, Van Tassell B, Vardeny O. Nutrition and heart failure: impact of drug therapies and management strategies. Nutr Clin Pract 2009; 24:60-75. [PMID: 19244150 DOI: 10.1177/0884533608329299] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Nutrition impairment commonly occurs in patients with heart failure and affects disease progression. Vitamin and mineral deficiencies are associated with early mortality, particularly in patients classified as cachectic. Guideline-based therapies approved for heart failure, such as loop diuretics, angiotensin-converting enzyme inhibitors and angiotensin receptor blockers, aldosterone antagonists, and beta-adrenergic blockers, can lead to electrolyte abnormalities and predispose to some vitamin and micronutrient deficits. Clinical trial evidence in support of supplementary vitamin and mineral therapies for heart failure patients is limited with the exception of documented calcium and possibly vitamin D, thiamine, and coenzyme Q10 deficiencies. This area is gaining significant attention, and research is ongoing. The clinician can help minimize morbidity from nutrition impairment through appropriate monitoring and correction of baseline and medication-induced electrolyte imbalances, in addition to vitamin and mineral supplementation when appropriate.
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Affiliation(s)
- Steven P Dunn
- Department of Pharmacy Services, University of Kentucky, 800 Rose Street, Rm H-112B, Lexington, KY 40536-0293, USA.
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Abstract
OBJECTIVE Previous studies demonstrated myocardial dysfunction after electrical shock and indicated it may be related to free radicals. Whether the free radicals are generated after electrical shock has not been documented at the cellular level. This study was to investigate whether electrical shock generates intracellular free radicals inside cardiomyocytes and to evaluate whether reducing intracellular free radicals by pretreatment of ascorbic acid would reduce the contractile dysfunction after electrical shock. DESIGN Randomized prospective animal study. SETTING University affiliated research laboratory. SUBJECTS Sprague-Dawley rats. INTERVENTIONS Cardiomyocytes isolated from adult male rats were divided into four groups: (1) electrical shock alone; (2) electrical shock pretreated with ascorbic acid; (3) pretreated with ascorbic acid alone; and (4) control. Ascorbic acid (0.2 mM) was administrated in the perfusate of the ascorbic acid + electrical shock and ascorbic acid groups. A 2-J electrical shock was delivered to the electrical shock and ascorbic acid + electrical shock groups. MEASUREMENTS AND MAIN RESULTS DCFH-DA-loaded cardiomyocytes showed increased intracellular free radicals after electrical shock. The contractions and Ca2+ transients were recorded optically with fura-2 loading. Within 4 mins after electrical shock in the electrical shock group, the length shortening decreased from 8.4% +/- 2.5% to 5.6% +/- 3.4% (p = 0.000) and the Ca2+ transient decreased from 1.15 +/- 0.13 au to 1.08 +/- 0.1 au (p = 0.038). Compared with control, a significant difference in length shortening (p = 0.001) but not Ca2+ transient (p = 0.052) was noted. In the presence of ascorbic acid, electrical shock did not affect length shortening and Ca2+ transient. CONCLUSION Electrical shock generates free radicals inside the cardiomyocyte, and causes contractile impairment and associated decrease of Ca transient. Administering ascorbic acid may improve such damage by eliminating free radicals.
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Mak S. Intracoronary 17 β-Estradiol and the Inotropic Response to Dobutamine in Postmenopausal Women. J Womens Health (Larchmt) 2008; 17:1499-503. [DOI: 10.1089/jwh.2007.0768] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Susanna Mak
- Clinical Cardiovascular Research Laboratory, Mount Sinai Hospital, and Division of Cardiology, Department of Medicine, University of Toronto, Ontario, Canada
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Root-Bernstein R, Dillon PF, Hollingsworth R. A tethered ascorbate-norepinephrine compound, 4-UT, displays long-acting adrenergic activity on rabbit aortic smooth muscle. Drug Dev Res 2008. [DOI: 10.1002/ddr.20250] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Newsom SA, Paxton RJ, Rynn GM, Bell C. Influence of ascorbic acid on the thermic effect of feeding in overweight and obese adult humans. Obesity (Silver Spring) 2008; 16:1749-54. [PMID: 18551121 DOI: 10.1038/oby.2008.304] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The thermic effect of feeding (TEF: increase in energy expenditure following acute energy intake) is an important physiological determinant of total daily energy expenditure and thus energy balance. Approximately 40% of TEF is believed to be mediated by sympathoadrenal activation and consequent beta-adrenergic receptor stimulation of metabolism. In sedentary adults, acute administration of ascorbic acid, a potent antioxidant, augments the thermogenic response to beta-adrenergic stimulation. We hypothesized that acute ascorbic acid administration augments TEF in sedentary overweight and obese adults. Energy expenditure was determined (ventilated hood technique) before and 4 h after consumption of a liquid-mixed meal (caloric equivalent 40% of resting energy expenditure (REE)) in 11 sedentary, overweight/obese adults (5 men, 6 women; age: 24 +/- 2 years; BMI: 28.5 +/- 1.0 kg/m(2) (mean +/- s.e.)) on two separate, randomly ordered occasions: during continuous intravenous administration of saline (placebo control) and/or ascorbic acid (0.05 g/kg fat-free mass). Acute ascorbic acid administration prevented the increase in plasma concentration of oxidized low-density lipoprotein in the postprandial state (P = 0.04), but did not influence REE (1,668 +/- 107 kcal/day vs.1,684 +/- 84 kcal/day; P = 0.91) or the area under the TEF response curve (33.4 +/- 2.4 kcal vs. 30.5 +/- 3.6 kcal; P = 0.52) (control vs. ascorbic acid, respectively). Furthermore, acute ascorbic acid administration had no effect on respiratory exchange ratio, heart rate, or arterial blood pressure in the pre- and postabsorptive states (all P > 0.64). These data imply that the attenuated TEF commonly observed with sedentary lifestyle and obesity is not modulated by ascorbic acid-sensitive oxidative stress.
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Affiliation(s)
- Sean A Newsom
- Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, USA
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Mitoff PR, Al-Hesayen A, Azevedo E, Newton GE, Mak S. Sex differences in basal hemodynamics and left ventricular function in humans with and without heart failure. Am Heart J 2007; 154:575-80. [PMID: 17719309 DOI: 10.1016/j.ahj.2007.04.047] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/03/2006] [Accepted: 04/25/2007] [Indexed: 11/28/2022]
Abstract
BACKGROUND Women with systolic heart failure (HF) demonstrate better survival than men. Whether sex differences occur in hemodynamics or measures of left ventricular (LV) function is not well understood. METHODS We retrospectively analyzed a cohort who underwent evaluation by right heart catheterization +/- micromanometer-tipped catheterization of the LV. Two groups, defined at the time of catheterization, were studied: normal LV (NLV) function or HF (LV ejection fraction <35%, New York Heart Association II-III symptoms). For each female, we identified 2 male controls matched for age and LV ejection fraction in the HF group. RESULTS In the NLV group, we matched 73 men (56 +/- 10 years) to 39 women (56 +/- 10 years). In the HF group, we matched 71 men (57 +/- 10 years) to 36 women (57 +/- 10 years). In the NLV group, women had higher heart rate and lower right atrial pressure, mean pulmonary artery pressure, and pulmonary capillary wedge pressure. Left ventricular peak systolic pressure was higher, and LV end-diastolic pressure was lower in women. In the HF group, no sex differences were observed in any hemodynamic measurement. In both groups, no sex differences were observed in isovolumic contractility or relaxation. CONCLUSIONS Sex differences in hemodynamics are observed in patients with NLV function but not with HF. The intrinsic or extrinsic factors responsible for sex differences observed in patients with NLV function may be eclipsed by the HF disease state or its treatment.
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Affiliation(s)
- Peter R Mitoff
- Clinical Cardiovascular Science Research Laboratory, Mount Sinai Hospital, Toronto, Ontario, Canada
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Castro P, Vukasovic JL, Chiong M, Díaz-Araya G, Alcaino H, Copaja M, Valenzuela R, Greig D, Pérez O, Corbalan R, Lavandero S. Effects of carvedilol on oxidative stress and chronotropic response to exercise in patients with chronic heart failure. Eur J Heart Fail 2007; 7:1033-9. [PMID: 16227141 DOI: 10.1016/j.ejheart.2004.11.009] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/23/2004] [Revised: 09/09/2004] [Accepted: 11/11/2004] [Indexed: 10/25/2022] Open
Abstract
BACKGROUND Our previous studies suggest that the increase in heart rate from rest to peak exercise is reduced in patients with chronic heart failure (CHF) and this is associated with increased oxidative stress, as determined by malondialdehyde (MDA) plasma levels. AIM To investigate the effects of carvedilol on the heart rate response to exercise and oxidative stress in patients with CHF. METHODS AND RESULTS Thirty stable NYHA classes II-III CHF patients received carvedilol therapy for 6 months, at a mean maintenance dose of 25 mg (range 6.25-50 mg/day). After treatment, the patients showed a significant improvement in their functional NYHA class (p=0.013), increased left ventricular ejection fraction (LVEF) (24+/-1.4% to 31+/-2.3%, p=0.003) and 6-min walk distance (499+/-18 to 534+/-18 m, p=0.03), without changes in the peak VO2. At baseline, norepinephrine (NE) plasma levels increased with exercise (510+/-51 to 2513+/-230 pg/mL, p<0.001), and these levels were not affected by carvedilol. Chronotropic responsiveness index (increase in heart rate divided by the increase in NE from rest to peak exercise) was not changed by carvedilol (0.049+/-0.001 to 0.042+/-0.001, p=0.6). MDA levels of CHF patients decreased after treatment with carvedilol (2.4+/-0.2 to 1.1+/-0.2 microM, p<0.001), without changes in antioxidant enzyme activities. CONCLUSIONS Carvedilol treatment in patients with CHF results in reduced oxidative stress without restoration of the chronotropic responsiveness index.
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Affiliation(s)
- Pablo Castro
- Cardiovascular Diseases, Universidad Católica de Chile, Santiago, Chile.
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Bell C, Stob NR, Seals DR. Thermogenic responsiveness to beta-adrenergic stimulation is augmented in exercising versus sedentary adults: role of oxidative stress. J Physiol 2006; 570:629-35. [PMID: 16308351 PMCID: PMC1479870 DOI: 10.1113/jphysiol.2005.098756] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Revised: 09/14/2005] [Accepted: 11/17/2005] [Indexed: 12/17/2022] Open
Abstract
Beta-adrenergic receptor (beta-AR) modulation of resting and postprandial energy expenditure (EE) is augmented in regularly exercising compared with sedentary adults, but the underlying physiological mechanisms are unknown. Differences in thermogenic responsiveness to beta-AR stimulation, perhaps secondary to reactive oxygen species (ROS) bioactivity, may be involved. To determine habitual exercise-related differences in beta-AR thermogenic responsiveness and the possible influence of ROS, we measured the percentage increase in EE (DeltaEE%; indirect calorimetry, ventilated hood method) above resting EE in response to non-specific beta-AR stimulation (intravenous isoproterenol (isoprenaline): 6, 12 and 24 ng (kg fat-free mass)-1 min-1) in 25 sedentary (11 males; 51+/-4 years; body mass index 25.0+/-0.8 kg m-2, maximal oxygen uptake 29+/-1 ml kg-1 min-1 (mean+/-s.e.m.)) and 14 habitually aerobic exercising (9 males, 46+/-6 years, 23.1+/-0.7 kg m-2, 44+/-3 ml kg-1 min-1) healthy adults under normal (control) conditions and during acute intravenous administration of a potent antioxidant, ascorbic acid (vitamin C; 0.04 g (kg fat-free mass)-1). DeltaEE% was greater (P=0.02) in the habitually exercising (8.6+/-1.2, 12.9+/-1.2, 20.0+/-1.4) versus sedentary (6.3+/-0.7, 10.4+/-0.8, 16.0+/-1.0) adults. Ascorbic acid increased (P=0.01) DeltaEE% only in the sedentary adults (to 9.5+/-0.9, 12.4+/-0.7, 18.5+/-0.8), abolishing baseline group differences. DeltaEE% was not related to the amount of body fat, sex, or any other baseline characteristic. Thermogenic responsiveness to beta-AR stimulation is augmented in habitually exercising adults. The mechanism is ascorbic acid dependent, suggesting that it may be linked to decreased ROS bioactivity. Our findings advance a novel mechanism by which habitual physical activity may modulate EE in humans, with potential implications for energy balance and body weight control.
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Affiliation(s)
- Christopher Bell
- Department of Integrative Physiology, University of Colorado, Boulder, CO, USA.
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Mak S, Overgaard CB, Newton GE. Effect of vitamin C and L-NMMA on the inotropic response to dobutamine in patients with heart failure. Am J Physiol Heart Circ Physiol 2005; 289:H2424-8. [PMID: 16040714 DOI: 10.1152/ajpheart.00453.2005] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The positive effect of vitamin C on left ventricular (LV) inotropic responses to dobutamine, observed in patients with preserved LV function, is lost in heart failure (HF). We tested the hypothesis that in HF, endogenous nitric oxide (NO) opposes the positive effect of vitamin C on adrenergically stimulated contractility by examining the effects of vitamin C on dobutamine responses during NO synthase inhibition. In 11 HF patients, a micromanometer-tipped catheter was inserted into the LV and an infusion catheter was positioned in the left main coronary artery. The peak positive rate of change of LV pressure (LV +dP/dt) was measured in response to intravenous dobutamine (Dob-1). After recontrol, intracoronary N(G)-monomethyl-L-arginine (l-NMMA) was infused before reinfusion of dobutamine (L-NMMA + Dob-2). Finally, intracoronary vitamin C was infused in addition to intracoronary L-NMMA and dobutamine (L-NMMA + Dob-2 + vitamin C). Intracoronary L-NMMA alone had no effect on LV +dP/dt. After a stable inotropic response to intracoronary L-NMMA and dobutamine was established, the addition of intracoronary vitamin C resulted in a modest but significant increase in LV +dP/dt. The change in LV +dP/dt in response to dobutamine alone was 25 +/- 5%, with intracoronary L-NMMA, 27 +/- 6%, and with intracoronary L-NMMA plus vitamin C, 37 +/- 5% (P < 0.05 vs. Dob-1 and L-NMMA + Dob-2). These findings demonstrate that an interaction between endogenous NO and redox environment exists and exerts some influence on stimulated contractility in HF.
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Affiliation(s)
- Susanna Mak
- Cardiovascular Clinical Research Laboratory, Div. of Cardiology, Mount Sinai Hospital, 600 University Ave., Rm. 1543, Toronto, Ontario, Canada M5G 1X5
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Gavin AD, Struthers AD. Allopurinol reduces B-type natriuretic peptide concentrations and haemoglobin but does not alter exercise capacity in chronic heart failure. Heart 2005; 91:749-53. [PMID: 15894768 PMCID: PMC1768933 DOI: 10.1136/hrt.2004.040477] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
OBJECTIVE To study whether the effect of allopurinol on improvement of endothelial dysfunction in chronic heart failure (CHF) translates into improved exercise capacity and to examine whether allopurinol also improves B-type natriuretic peptide (BNP), the other important prognostic marker of CHF. DESIGN Randomised, double blind, placebo controlled crossover trial. SETTING Teaching hospital. PATIENTS 50 patients with CHF (New York Heart Association functional classes II and III) were recruited. INTERVENTIONS 50 patients with CHF were randomly assigned to three months' treatment with allopurinol (300 mg/day) or placebo. At two and three months into treatment, they underwent a modified Bruce exercise protocol and a six minute walk test. Blood was taken for BNP and haemoglobin analysis. RESULTS Neither exercise test was altered by allopurinol. However, plasma BNP concentrations fell significantly (p = 0.035) with allopurinol (11.9 pmol/l) versus placebo (14.4 pmol/l). Haemoglobin concentrations also fell highly significantly with allopurinol (p = 0.001). CONCLUSIONS An important negative finding is that despite high hopes for it, allopurinol had no effect on exercise capacity in CHF. On the other hand, allopurinol did reduce BNP, which is the best available surrogate marker for prognosis in CHF.
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Affiliation(s)
- A D Gavin
- Division of Medicine & Therapeutics, Ninewells Hospital & Medical School, Dundee, UK
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Bell C, Carson JM, Motte NW, Seals DR. Ascorbic acid does not affect the age-associated reduction in maximal cardiac output and oxygen consumption in healthy adults. J Appl Physiol (1985) 2005; 98:845-9. [PMID: 15501926 DOI: 10.1152/japplphysiol.00790.2004] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Maximal aerobic capacity (V̇o2max) decreases progressively with age, primarily because of a reduction in maximal cardiac output (Q̇max). This age-associated decline in V̇o2max may be partially mediated by the development of oxidative stress that can suppress β-adrenergic-receptor responsiveness and, consequently, reduce Q̇max. To test this hypothesis, V̇o2max (indirect calorimetry) and Q̇max (open-circuit acetylene breathing) were determined in 12 young (23 ± 1 yr, mean ± SE) and 10 older (61 ± 1 yr) adults following systemic infusion of either saline (control) and/or the powerful antioxidant ascorbic acid (acute: bolus 0.06; drip 0.02 g/kg fat-free mass) and following chronic 30-day oral administration of ascorbic acid (500 mg/day). Plasma ascorbic acid concentration was not different between young and older adults and was increased similarly, independent of age [change (Δ) acute = 1,055 ± 117%; Δ chronic = 62 ± 19%]. Oxidized low-density lipoprotein concentration was greater ( P < 0.001) in older (57 ± 5 U/l) compared with young (34 ± 3 U/l) adults and was reduced in both groups ( P < 0.02) following acute (Δ = −6 ± 2%) but not chronic ( P = 0.18) ascorbic acid administration. Control (baseline) V̇o2max and Q̇max were positively related ( r = 0.76, P < 0.001) and were lower ( P < 0.05) in older (34 ± 2 ml·kg−1·min−1; 16.1 ± 1.1 l/min) compared with young (43 ± 3 ml·kg−1·min−1; 20.2 ± 0.9 l/min) adults. Following ascorbic acid administration, neither V̇o2max (young acute = 41 ± 2; young chronic = 42 ± 2; older acute = 34 ± 2; older chronic = 34 ± 2 ml·kg−1·min−1) nor Q̇max (young acute = 20.1 ± 0.9; young chronic = 19.1 ± 0.8; older acute = 16.2 ± 1.1; older chronic = 16.6 ± 1.4 l/min) was changed. These data suggest that ascorbic acid administration does not affect the age-associated reduction in Q̇max and V̇o2max.
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Affiliation(s)
- Christopher Bell
- Department of Integrative Physiology, 354UCB, Univ. of Colorado, Boulder, CO 80309-0354, USA.
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Vergely C, Goirand F, Ecarnot-Laubriet A, Renard C, Moreau D, Guilland JC, Dumas M, Rochette L. Vitamin C deficiency exerts paradoxical cardiovascular effects in osteogenic disorder Shionogi (ODS) rats. J Nutr 2004; 134:729-35. [PMID: 15051818 DOI: 10.1093/jn/134.4.729] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Vitamin C is considered to be a very efficient water-soluble antioxidant, for which several new cardiovascular properties were recently described. The aim of this study was to determine in vivo the effects of a severe depletion of vitamin C on cardiac and vascular variables and reperfusion arrhythmias. For this purpose, we used a mutant strain of Wistar rats, osteogenic disorder Shionogi (ODS). After 15 d of consuming a vitamin C-deficient diet, ODS rats had a 90% decrease in plasma and tissue levels of ascorbate compared with ODS vitamin C-supplemented rats and normal Wistar rats. However, plasma antioxidant capacity, proteins, alpha-tocopherol, urate, catecholamines, lipids, and nitrate were not influenced by the vitamin C deficiency in ODS rats. Moreover, there was no difference between ODS vitamin C-deficient and -supplemented rats in heart rate and arterial pressure. After 5 min of an in vivo regional myocardial ischemia, various severe arrhythmias were observed, but their intensities were not modified by vitamin C in vitamin C-deficient ODS rats. The vascular reactivity, measured in vitro on thoracic arteries, was not altered by ascorbate deficiency in ODS rats. These unexpected results suggest that unidentified compensatory mechanisms play a role in maintaining normal cardiac function and vascular reactivity in vitamin C-deficient rats.
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Affiliation(s)
- Catherine Vergely
- Laboratoire de Physiopathologie et Pharmacologie Cardio-vasculaires Expérimentales, IFR n degrees 100, Facultés de Médecine et Pharmacie, 21000 Dijon, France.
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Mak S, Newton GE. Redox modulation of the inotropic response to dobutamine is impaired in patients with heart failure. Am J Physiol Heart Circ Physiol 2003; 286:H789-95. [PMID: 14551049 DOI: 10.1152/ajpheart.00633.2003] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
It has been suggested that oxidative stress contributes to impaired left ventricular (LV) contractility in the setting of heart failure (HF). To test this hypothesis, we studied the effect of an antioxidant on contractility at rest and in response to dobutamine in 10 HF patients. We hypothesized that vitamin C would augment contractility in HF and that this effect would be of a greater magnitude in HF patients compared with patients with normal LV (NLV) function. Data from 10 patients with NLV function who participated in this study are included in this report and have been published elsewhere. A micromanometer-tipped catheter was introduced into the LV. In the experimental protocol, an infusion catheter was positioned in the left main coronary artery. The peak positive rate of change of LV pressure (LV +dP/dt) was measured in response to the intravenous infusion of dobutamine before and during the intracoronary infusion of vitamin C (96 mg/min). Vitamin C had no effect on basal LV +dP/dt in either HF or NLV groups. The infusion of vitamin C augmented the LV +dP/dt response to dobutamine by 22 +/- 4% in the NLV function group. In contrast, vitamin C had no effect on the inotropic response to dobutamine in the HF group. In the control protocol, without vitamin C, no differences were observed between responses to two sequential dobutamine infusions in either group (HF, n = 11; NLV, n = 9). Therefore, a positive effect of vitamin C on contractility was limited to patients with NLV function. The absence of this effect in HF patients may suggest that normal redox responsiveness is lost in this disease state.
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Affiliation(s)
- Susanna Mak
- Bayer Cardiovascular Clinical Research Laboratory, Division of Cardiology, Mount Sinai Hospital, University of Toronto, Ontario, Canada
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Heymes C, Bendall JK, Ratajczak P, Cave AC, Samuel JL, Hasenfuss G, Shah AM. Increased myocardial NADPH oxidase activity in human heart failure. J Am Coll Cardiol 2003; 41:2164-71. [PMID: 12821241 DOI: 10.1016/s0735-1097(03)00471-6] [Citation(s) in RCA: 423] [Impact Index Per Article: 20.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
OBJECTIVES This study was designed to investigate whether nicotinamide adenine dinucleotide 3-phosphate (reduced form) (NADPH) oxidase is expressed in the human heart and whether it contributes to reactive oxygen species (ROS) production in heart failure. BACKGROUND A phagocyte-type NADPH oxidase complex is a major source of ROS in the vasculature and is implicated in the pathophysiology of hypertension and atherosclerosis. An increase in myocardial oxidative stress due to excessive production of ROS may be involved in the pathophysiology of congestive heart failure. Recent studies have suggested an important role for myocardial NADPH oxidase in experimental models of cardiac disease. However, it is unknown whether NADPH oxidase is expressed in the human myocardium or if it has any role in human heart failure. METHODS Myocardium of explanted nonfailing (n = 9) and end-stage failing (n = 13) hearts was studied for the expression of NADPH oxidase subunits and oxidase activity. RESULTS The NADPH oxidase subunits p22(phox), gp91(phox), p67(phox), and p47(phox) were all expressed at messenger ribonucleic acid and protein level in cardiomyocytes of both nonfailing and failing hearts. NADPH oxidase activity was significantly increased in end-stage failing versus nonfailing myocardium (5.86 +/- 0.41 vs. 3.72 +/- 0.39 arbitrary units; p < 0.01). The overall level of oxidase subunit expression was unaltered in failing compared with nonfailing hearts. However, there was increased translocation of the regulatory subunit, p47(phox), to myocyte membranes in failing myocardium. CONCLUSIONS This is the first report of the presence of NADPH oxidase in human myocardium. The increase in NADPH oxidase activity in the failing heart may be important in the pathophysiology of cardiac dysfunction by contributing to increased oxidative stress.
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Affiliation(s)
- Christophe Heymes
- Department of Cardiology, Guy's King's and St. Thomas's School of Medicine, King's College, London, United Kingdom
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Root-Bernstein R, Dillon PF. Fostering venture research: A case study of the discovery that ascorbate enhances adrenergic drug activity. Drug Dev Res 2002. [DOI: 10.1002/ddr.10110] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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Zafari AM, Harrison DG. Free radicals in heart failure: therapeutic targets for old and new drugs. CONGESTIVE HEART FAILURE (GREENWICH, CONN.) 2002; 8:129-30. [PMID: 12045380 DOI: 10.1111/j.1527-5299.2002.00300.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- A Maziar Zafari
- Emory University School of Medicine, Department of Medicine, Division of Cardiology, Atlanta, GA 30322, USA.
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Abstract
There is extensive experimental evidence from in vitro and animal experiments that congestive heart failure (CHF) is a state of oxidative stress. Moreover, in animal models, the development of CHF is accompanied by changes in the antioxidant defense mechanisms of the myocardium as well as evidence of oxidative myocardial injury. This has led to the hypothesis that oxidative stress may be a mechanism of disease progression in CHF. Indeed, many patients consume antioxidant supplements making the assumption that no harm will result and, possibly, that this therapy will yield some clinical benefits. The focus of this review is to examine the oxidative stress hypothesis of CHF as it pertains to humans. To date, human studies that have sought evidence for a role of oxidative stress in patients with CHF have fallen short of providing strong support for this hypothesis. Studies that have demonstrated an association between oxidant stress and CHF are small and are hindered by methodologic limitations that diminish the impact of their conclusions. Randomized trials of antioxidant supplementation for CHF are scarce, and to our knowledge no study yet convincingly demonstrates any benefit from consuming antioxidant supplements. Therefore, the available evidence is insufficient to support or negate the oxidative stress hypothesis of CHF and the use of antioxidants cannot be recommended as a specific therapy for this condition.
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Affiliation(s)
- S Mak
- Mount Sinai Hospital, University of Toronto, Toronto, Ontario, Canada
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Shite J, Qin F, Mao W, Kawai H, Stevens SY, Liang C. Antioxidant vitamins attenuate oxidative stress and cardiac dysfunction in tachycardia-induced cardiomyopathy. J Am Coll Cardiol 2001; 38:1734-40. [PMID: 11704389 DOI: 10.1016/s0735-1097(01)01596-0] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
OBJECTIVES We administered antioxidant vitamins to rabbits with pacing-induced cardiomyopathy to assess whether antioxidant therapy retards the progression of congestive heart failure (CHF). BACKGROUND Although oxidative stress is increased in CHF, whether progression of heart failure could be prevented or reduced by antioxidants is not known. METHODS Rabbits with chronic cardiac pacing and sham operation were randomized to receive a combination of beta-carotene, ascorbic acid and alpha-tocopherol, alpha-tocopherol alone or placebo over eight weeks. Echocardiography was used to measure cardiac function weekly. Resting hemodynamics and in vivo myocardial beta-adrenergic responsiveness were studied at week 8. Animals were then sacrificed for measuring myocardial beta-receptor density, norepinephrine (NE) uptake-1 site density, sympathetic neuronal marker profiles, tissue-reduced glutathione/oxidized glutathione (GSH/GSSG) ratio and oxidative damage of mitochondrial DNA (mtDNA). RESULTS Rapid cardiac pacing increased myocardial oxidative stress as evidenced by reduced myocardial GSH/GSSG ratio and increased oxidized mtDNA and produced cardiac dysfunction, beta-adrenergic subsensitivity, beta-receptor downregulation, diminished sympathetic neurotransmitter profiles and reduced NE uptake-1 carrier density. A combination of antioxidant vitamins reduced the myocardial oxidative stress, attenuated cardiac dysfunction and prevented myocardial beta-receptor downregulation and sympathetic nerve terminal dysfunction. Administration of alpha-tocopherol alone produced similar effects, but the effects were less marked than those produced by the three vitamins together. Vitamins produced no effects in sham-operated animals. CONCLUSIONS Antioxidant vitamins reduced tissue oxidative stress in CHF and attenuated the associated cardiac dysfunction, beta-receptor downregulation and sympathetic nerve terminal abnormalities. The findings suggest that antioxidant therapy may be efficacious in human CHF.
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Affiliation(s)
- J Shite
- Cardiology Unit, Department of Medicine, University of Rochester Medical Center, Rochester, New York 14642, USA
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Abstract
Established risk factors for cardiovascular disease (CVD), such as hypertension, smoking and diabetes mellitus, explain only some of the observed variation in clinical events. This has maintained interest in other nutritional and biochemical factors that might contribute to the underlying pathophysiology of CVD. All of these risk factors are associated with increased oxidative stress in the vessel wall, which may contribute to CVD by several mechanisms. Studies in animal models of CVD have suggested that natural and synthetic anti-oxidants can prevent the development of clinical end points. These observations have generated the hypothesis that anti-oxidant therapy might also prevent CVD in human populations. This has been supported by epidemiological studies showing a negative correlation between circulating concentrations or dietary intake of natural anti-oxidant vitamins and CVD event rate. Many studies have also demonstrated a beneficial effect of anti-oxidants on surrogate markers of CVD such as endothelial function and lipoprotein oxidation. However, the results of large prospective randomised controlled intervention trials, mostly involving vitamin E in patients at increased risk of CVD, have been disappointing and have failed to demonstrate the anticipated benefits. This paper will critically examine the evidence and try to offer some explanation for the apparent failure of animal and epidemiological data to translate into meaningful clinical benefits.
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Affiliation(s)
- S Maxwell
- Clinical Pharmacology Unit, The University of Edinburgh, Western General Hospital, Crewe Road, Edinburgh, EH4 2XU, UK.
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