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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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Rozemeijer S, Hemilä H, van Baaren M, de Man AM. Vitamin C may reduce troponin and CKMB levels after PCI and CABG: a meta-analysis. BMC Cardiovasc Disord 2023; 23:475. [PMID: 37735625 PMCID: PMC10512653 DOI: 10.1186/s12872-023-03459-6] [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: 02/14/2023] [Accepted: 08/19/2023] [Indexed: 09/23/2023] Open
Abstract
BACKGROUND Ischemia/reperfusion injury contributes to periprocedural myocardial injury (PMI) in patients undergoing percutaneous coronary intervention (PCI) or coronary artery bypass grafting (CABG). PMI can be estimated by the elevation of troponin (Tn) and creatine kinase-MB (CKMB) plasma levels, and it is associated with increased risk of cardiovascular events and mortality. Vitamin C might have a beneficial effect on PMI by improving endothelial function, improving myocardial perfusion, and by reducing oxidative stress generated during/after reperfusion. In several small animal models of cardiac stress, vitamin C reduced the increase in Tn and CKMB levels. The aim of this meta-analysis was to investigate whether vitamin C administration may have an effect on Tn and CKMB levels in patients undergoing PCI or CABG. METHODS We searched PubMed, Cochrane, Embase and Scopus databases for controlled clinical trials reporting on Tn and CKMB levels in adult patients who underwent PCI or CABG and received vitamin C. As secondary outcomes we collected data on biomarkers of oxidative stress in the included trials. In our meta-analysis, we used the relative scale and estimated the effect as the ratio of means. RESULTS We found seven controlled trials which included 872 patients. All included trials administered vitamin C intravenously, with a range from 1 to 16 g/day, and all initiated vitamin administration prior to the procedure. Vitamin C decreased peak Tn plasma levels in four trials on average by 43% (95% CI: 13 to 63%, p = 0.01) and peak CKMB plasma levels in five trials by 14% (95% CI: 8 to 21%, p < 0.001). Vitamin C also significantly decreased the biomarkers of oxidative stress. CONCLUSIONS Vitamin C may decrease cardiac enzyme levels in patients undergoing elective PCI or CABG. This may be explained partially by its antioxidant effects. Our findings encourage further research on vitamin C administration during cardiac procedures and in other clinical contexts that increase the level of cardiac enzymes. Future studies should search for an optimal dosing regimen, taking baseline and follow-up plasma vitamin C levels into account.
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Affiliation(s)
- Sander Rozemeijer
- Department of Intensive Care Medicine, Research VUmc Intensive Care (REVIVE), Amsterdam Cardiovascular Science (ACS), Amsterdam Infection and Immunity Institute (AI&II), Amsterdam Medical Data Science (AMDS), Amsterdam UMC, Location VUmc, Vrije Universiteit Amsterdam, De Boelelaan 1117, Amsterdam, 1081 HV The Netherlands
- Department of Anesthesiology, Amsterdam UMC, Location VUmc, Vrije Universiteit Amsterdam, De Boelelaan 1117, Amsterdam, 1081 HV The Netherlands
| | - Harri Hemilä
- Department of Public Health, University of Helsinki, Helsinki, Finland
| | - Marlinde van Baaren
- Department of Intensive Care Medicine, Research VUmc Intensive Care (REVIVE), Amsterdam Cardiovascular Science (ACS), Amsterdam Infection and Immunity Institute (AI&II), Amsterdam Medical Data Science (AMDS), Amsterdam UMC, Location VUmc, Vrije Universiteit Amsterdam, De Boelelaan 1117, Amsterdam, 1081 HV The Netherlands
| | - Angélique M.E. de Man
- Department of Intensive Care Medicine, Research VUmc Intensive Care (REVIVE), Amsterdam Cardiovascular Science (ACS), Amsterdam Infection and Immunity Institute (AI&II), Amsterdam Medical Data Science (AMDS), Amsterdam UMC, Location VUmc, Vrije Universiteit Amsterdam, De Boelelaan 1117, Amsterdam, 1081 HV The Netherlands
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3
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Mace EH, Kimlinger MJ, Billings FT, Lopez MG. Targeting Soluble Guanylyl Cyclase during Ischemia and Reperfusion. Cells 2023; 12:1903. [PMID: 37508567 PMCID: PMC10378692 DOI: 10.3390/cells12141903] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Accepted: 07/17/2023] [Indexed: 07/30/2023] Open
Abstract
Ischemia and reperfusion (IR) damage organs and contribute to many disease states. Few effective treatments exist that attenuate IR injury. The augmentation of nitric oxide (NO) signaling remains a promising therapeutic target for IR injury. NO binds to soluble guanylyl cyclase (sGC) to regulate vasodilation, maintain endothelial barrier integrity, and modulate inflammation through the production of cyclic-GMP in vascular smooth muscle. Pharmacologic sGC stimulators and activators have recently been developed. In preclinical studies, sGC stimulators, which augment the reduced form of sGC, and activators, which activate the oxidized non-NO binding form of sGC, increase vasodilation and decrease cardiac, cerebral, renal, pulmonary, and hepatic injury following IR. These effects may be a result of the improved regulation of perfusion and decreased oxidative injury during IR. sGC stimulators are now used clinically to treat some chronic conditions such as heart failure and pulmonary hypertension. Clinical trials of sGC activators have been terminated secondary to adverse side effects including hypotension. Additional clinical studies to investigate the effects of sGC stimulation and activation during acute conditions, such as IR, are warranted.
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Affiliation(s)
- Eric H Mace
- Department of Surgery, Vanderbilt University Medical Center, Medical Center North, Suite CCC-4312, 1161 21st Avenue South, Nashville, TN 37232-2730, USA
| | - Melissa J Kimlinger
- Vanderbilt University School of Medicine, 428 Eskind Family Biomedical Library and Learning Center, Nashville, TN 37240-0002, USA
| | - Frederic T Billings
- Department of Anesthesiology, Division of Critical Care Medicine, Vanderbilt University Medical Center, Medical Arts Building, Suite 422, 1211 21st Avenue South, Nashville, TN 37212-1750, USA
| | - Marcos G Lopez
- Department of Anesthesiology, Division of Critical Care Medicine, Vanderbilt University Medical Center, Medical Arts Building, Suite 422, 1211 21st Avenue South, Nashville, TN 37212-1750, USA
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Alva R, Mirza M, Baiton A, Lazuran L, Samokysh L, Bobinski A, Cowan C, Jaimon A, Obioru D, Al Makhoul T, Stuart JA. Oxygen toxicity: cellular mechanisms in normobaric hyperoxia. Cell Biol Toxicol 2022; 39:111-143. [PMID: 36112262 PMCID: PMC9483325 DOI: 10.1007/s10565-022-09773-7] [Citation(s) in RCA: 30] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Accepted: 09/07/2022] [Indexed: 12/15/2022]
Abstract
In clinical settings, oxygen therapy is administered to preterm neonates and to adults with acute and chronic conditions such as COVID-19, pulmonary fibrosis, sepsis, cardiac arrest, carbon monoxide poisoning, and acute heart failure. In non-clinical settings, divers and astronauts may also receive supplemental oxygen. In addition, under current standard cell culture practices, cells are maintained in atmospheric oxygen, which is several times higher than what most cells experience in vivo. In all the above scenarios, the elevated oxygen levels (hyperoxia) can lead to increased production of reactive oxygen species from mitochondria, NADPH oxidases, and other sources. This can cause cell dysfunction or death. Acute hyperoxia injury impairs various cellular functions, manifesting ultimately as physiological deficits. Chronic hyperoxia, particularly in the neonate, can disrupt development, leading to permanent deficiencies. In this review, we discuss the cellular activities and pathways affected by hyperoxia, as well as strategies that have been developed to ameliorate injury.
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Affiliation(s)
- Ricardo Alva
- Department of Biological Sciences, Brock University, St. Catharines, ON, L2S 3A1, Canada
| | - Maha Mirza
- Department of Biological Sciences, Brock University, St. Catharines, ON, L2S 3A1, Canada
| | - Adam Baiton
- Department of Biological Sciences, Brock University, St. Catharines, ON, L2S 3A1, Canada
| | - Lucas Lazuran
- Department of Biological Sciences, Brock University, St. Catharines, ON, L2S 3A1, Canada
| | - Lyuda Samokysh
- Department of Biological Sciences, Brock University, St. Catharines, ON, L2S 3A1, Canada
| | - Ava Bobinski
- Department of Biological Sciences, Brock University, St. Catharines, ON, L2S 3A1, Canada
| | - Cale Cowan
- Department of Biological Sciences, Brock University, St. Catharines, ON, L2S 3A1, Canada
| | - Alvin Jaimon
- Department of Biological Sciences, Brock University, St. Catharines, ON, L2S 3A1, Canada
| | - Dede Obioru
- Department of Biological Sciences, Brock University, St. Catharines, ON, L2S 3A1, Canada
| | - Tala Al Makhoul
- Department of Biological Sciences, Brock University, St. Catharines, ON, L2S 3A1, Canada
| | - Jeffrey A Stuart
- Department of Biological Sciences, Brock University, St. Catharines, ON, L2S 3A1, Canada.
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Stolmeijer R, van Ieperen E, Lameijer H, van Beest P, Ter Maaten JC, Ter Avest E. Haemodynamic effects of a 10-min treatment with a high inspired oxygen concentration in the emergency department: a prospective observational study. BMJ Open 2022; 12:e059848. [PMID: 36581986 PMCID: PMC9438193 DOI: 10.1136/bmjopen-2021-059848] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
UNLABELLED Previous studies show that prolonged exposure to a high inspired oxygen concentration (FiO2) is associated with unfavourable haemodynamic effects. Until now, it is unknown if similar effects also occur after oxygen therapy of limited duration in the emergency department (ED). OBJECTIVES To investigate the haemodynamic effects of a high FiO2 administered for a limited duration of time in patients who receive preoxygenation for procedural sedation and analgesia (PSA) in the ED. DESIGN, SETTINGS AND PARTICIPANTS In a prospective cohort study, cardiac output (CO), stroke volume (SV) and systemic vascular resistance (SVR) were measured using the Clearsight non-invasive CO monitoring system in patients who received preoxygenation for PSA in the ED. Measurements were performed at baseline, after 5 min of preoxygenation via a non-rebreathing mask at 15 /L min and after 5 min of flush rate oxygen administration. OUTCOMES MEASURES The primary outcome was defined as the change in CO (L/min) from baseline after subsequent preoxygenation with 15 L/min and flush rate. RESULTS Sixty patients were included. Mean CO at baseline was 6.5 (6.0-6.9) L/min and decreased to 6.3 (5.8-6.8) L/min after 5 min of oxygen administration at a rate of 15 L/min, and to 6.2 (5.7-6.70) L/min after another 5 min at flush rate (p=0.037). Mean SV remained relatively constant during this period, whereas mean SVR increased markedly (from 781 (649-1067), to 1244 (936-1695) to 1337 (988-1738) dyn/s/cm-5, p<0.001. Sixteen (27%) patients experienced a>10% decrease in CO. CONCLUSION Exposure of patients to a high FiO2 for 5-10 min results in a significant drop in CO in one out of four patients. Therefore, even in the ED and in prehospital care, where oxygen is administered for a limited amount of time, FiO2 should be titrated based on deficit whenever this is feasible and high flow oxygen should not be given as a routine treatment.
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Affiliation(s)
- Renate Stolmeijer
- Department of Emergency Medicine, University Medical Centre Groningen, Groningen, The Netherlands
| | - Ellen van Ieperen
- Department of Emergency Medicine, Medical Centre Leeuwarden, Leeuwarden, The Netherlands
| | - Heleen Lameijer
- Department of Emergency Medicine, Medical Centre Leeuwarden, Leeuwarden, The Netherlands
| | - Paul van Beest
- Department of Anaesthesiology, Medical Centre Leeuwarden, Leeuwarden, The Netherlands
| | - Jan Cornelis Ter Maaten
- Emergency Department, Department of Internal Medicine, University Medical Centre Groningen, Groningen, The Netherlands
| | - Ewoud Ter Avest
- HEMS, Kent, Surrey and Sussex Air Ambulance Trust, Redhill, Surrey, UK
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Hemilä H, Chalker E, de Man AME. Vitamin C May Improve Left Ventricular Ejection Fraction: A Meta-Analysis. Front Cardiovasc Med 2022; 9:789729. [PMID: 35282368 PMCID: PMC8913583 DOI: 10.3389/fcvm.2022.789729] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Accepted: 01/21/2022] [Indexed: 01/02/2023] Open
Abstract
Background Vitamin C deprivation can lead to fatigue, dyspnea, oedema and chest pain, which are also symptoms of heart failure (HF). In animal studies vitamin C has improved contractility and mechanical efficiency of the heart. Compared with healthy people, patients with HF have lower vitamin C levels, which are not explained by differences in dietary intake levels, and more severe HF seems to be associated with lower plasma vitamin C levels. This meta-analysis looks at the effect of vitamin C on left ventricular ejection fraction (LVEF). Methods We searched for trials reporting the effects of vitamin C on LVEF. We assessed the quality of the trials, and pooled selected trials using the inverse variance, fixed effect options. We used meta-regression to examine the association between the effect of vitamin C on LVEF level and the baseline LVEF level. Results We identified 15 trials, three of which were excluded from our meta-analysis. In six cardiac trials with 246 patients, vitamin C increased LVEF on average by 12.0% (95% CI 8.1–15.9%; P < 0.001). In six non-cardiac trials including 177 participants, vitamin C increased LVEF on average by 5.3% (95% CI 2.0–8.5%; P = 0.001). In meta-regression analysis we found that the effect of vitamin C was larger in trials with the lowest baseline LVEF levels with P = 0.001 for the test of slope. The meta-regression line crossed the null effect level at a baseline LVEF level close to 70%, with progressively greater benefit from vitamin C with lower LVEF levels. Some of the included trials had methodological limitations. In a sensitivity analysis including only the four most methodologically sound cardiac trials, the effect of vitamin C was not substantially changed. Conclusions In this meta-analysis, vitamin C increased LVEF in both cardiac and non-cardiac patients, with a strong negative association between the size of the vitamin C effect and the baseline LVEF. Further research on vitamin C and HF should be carried out, particularly in patients who have low LVEF together with low vitamin C intake or low plasma levels. Different dosages and different routes of administration should be compared.
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Affiliation(s)
- Harri Hemilä
- Department of Public Health, University of Helsinki, Helsinki, Finland
- *Correspondence: Harri Hemilä
| | - Elizabeth Chalker
- Biological Data Science Institute, Australian National University, Canberra, ACT, Australia
| | - Angelique M. E. de Man
- Department of Intensive Care Medicine, Amsterdam University Medical Centers, Amsterdam, Netherlands
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Balcarcel DR, Coates BM, Chong G, Sanchez-Pinto LN. Excessive Oxygen Supplementation in the First Day of Mechanical Ventilation Is Associated With Multiple Organ Dysfunction and Death in Critically Ill Children. Pediatr Crit Care Med 2022; 23:89-98. [PMID: 35119429 PMCID: PMC8820279 DOI: 10.1097/pcc.0000000000002861] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
OBJECTIVES To determine if greater cumulative exposure to oxygen despite adequate oxygenation over the first 24 hours of mechanical ventilation is associated with multiple organ dysfunction syndrome at 7 days and inhospital mortality in critically ill children. DESIGN Retrospective, observational cohort study. SETTING Two urban, academic PICUs. PATIENTS Patients less than 18 years old who required mechanical ventilation within 3 days of admission between 2010 and 2018 (Lurie Children's Hospital) or 2010 and 2016 (Comer Children's Hospital). INTERVENTIONS None. MEASUREMENTS AND MAIN RESULTS There were 5,406 mechanically ventilated patients, of which 960 (17.8%) had multiple organ dysfunction syndrome on day 7 of admission and 319 died (5.9%) during their hospitalization. Cumulative exposure to greater amounts of supplemental oxygen, while peripheral oxygen saturation was 95% or more during the first 24 hours of mechanical ventilation was independently associated with an increased risk of both multiple organ dysfunction syndrome on day 7 and inhospital mortality after adjusting for confounders. Patients in the highest quartile of cumulative oxygen exposure had an increased odds of multiple organ dysfunction syndrome on day 7 (adjusted odds ratio, 3.9; 95% CI, 2.7-5.9) and inhospital mortality (adjusted odds ratio, 1.7; 95% CI, 1.1-2.9), when compared with those in the lowest quartile of cumulative oxygen exposure after adjusting for age, presence of multiple organ dysfunction syndrome on day 1 of mechanical ventilation, immunocompromised state, and study site. CONCLUSIONS Greater cumulative exposure to excess supplemental oxygen in the first 24 hours of mechanical ventilation is independently associated with an increased risk of multiple organ dysfunction syndrome on day 7 of admission and inhospital mortality in critically ill children.
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Affiliation(s)
- Daniel R. Balcarcel
- Department of Pediatrics (Critical Care), Northwestern University Feinberg School of Medicine, Chicago, IL
| | - Bria M. Coates
- Department of Pediatrics (Critical Care), Northwestern University Feinberg School of Medicine, Chicago, IL
- Division of Critical Care, Ann & Robert H. Lurie Children’s Hospital of Chicago, Chicago, IL
| | - Grace Chong
- Section of Critical Care, The University of Chicago Comer Children’s Hospital, Chicago, IL
| | - L. Nelson Sanchez-Pinto
- Department of Pediatrics (Critical Care), Northwestern University Feinberg School of Medicine, Chicago, IL
- Division of Critical Care, Ann & Robert H. Lurie Children’s Hospital of Chicago, Chicago, IL
- Section of Critical Care, The University of Chicago Comer Children’s Hospital, Chicago, IL
- Department of Preventive Medicine (Health and Biomedical Informatics), Northwestern University Feinberg School of Medicine, Chicago, IL
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Petersen C, Loft FC, Aasvang EK, Vester‐Andersen M, Rasmussen LS, Wetterslev J, Jorgensen LN, Christensen R, Meyhoff CS. Hyperoxia and antioxidants during major non-cardiac surgery and risk of cardiovascular events: Protocol for a 2 × 2 factorial randomised clinical trial. Acta Anaesthesiol Scand 2020; 64:400-409. [PMID: 31849040 DOI: 10.1111/aas.13518] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Accepted: 11/28/2019] [Indexed: 11/28/2022]
Abstract
BACKGROUND Myocardial injury after non-cardiac surgery occurs in a high number of patients, resulting in increased mortality in the post-operative period. The use of high inspiratory oxygen concentrations may cause hyperoxia, which is associated with impairment of coronary blood flow. Furthermore, the surgical stress response increases reactive oxygen species, which is involved in several perioperative complications including myocardial injury and death. Avoidance of hyperoxia and substitution of reactive oxygen species scavengers may be beneficial. Our primary objective is to examine the effect of oxygen and added antioxidants for prevention of myocardial injury assessed by area under the curve for troponin measurements during the first three post-operative days. METHODS The VIXIE trial (VitamIn and oXygen Interventions and cardiovascular Events) is an investigator-initiated, blinded, 2 × 2 factorial multicentre clinical trial. We include 600 patients with cardiovascular risk factors undergoing major non-cardiac surgery. Participants are randomised to an inspiratory oxygen fraction of 0.80 or 0.30 during and for 2 hours after surgery and either an intravenous bolus of vitamin C and an infusion of N-acetylcysteine or matching placebo of both. The primary outcome is the area under the curve for high-sensitive cardiac troponin release during the first three post-operative days as a marker of the extent of myocardial injury. Secondary outcomes are mortality, non-fatal myocardial infarction and non-fatal serious adverse events within 30 days. PERSPECTIVE The current trial will provide further evidence for clinicians on optimal administration of perioperative oxygen in surgical patients with cardiovascular risks and the clinical effects of two common antioxidants.
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Affiliation(s)
- Cecilie Petersen
- Department of Anaesthesia and Intensive Care Bispebjerg and Frederiksberg Hospital University of Copenhagen Copenhagen Denmark
- Copenhagen Center for Translational Research Bispebjerg and Frederiksberg Copenhagen University Hospital Copenhagen Denmark
| | - Frederik C. Loft
- Department of Anaesthesia and Intensive Care Bispebjerg and Frederiksberg Hospital University of Copenhagen Copenhagen Denmark
- Copenhagen Center for Translational Research Bispebjerg and Frederiksberg Copenhagen University Hospital Copenhagen Denmark
| | - Eske K. Aasvang
- Department of Clinical Medicine University of Copenhagen Copenhagen Denmark
- Department of Anaesthesia Centre for Cancer and Organ Diseases Rigshospitalet University of Copenhagen Copenhagen Denmark
| | - Morten Vester‐Andersen
- Herlev Anaesthesia Critical and Emergency Care Science Unit (ACES) Department of Anaesthesiology Copenhagen University Hospital Herlev‐Gentofte Herlev Denmark
| | - Lars S. Rasmussen
- Department of Clinical Medicine University of Copenhagen Copenhagen Denmark
- Department of Anaesthesia Center of Head and Orthopaedics Rigshospitalet University of Copenhagen Copenhagen Denmark
| | - Jørn Wetterslev
- Copenhagen Trial Unit Centre for Clinical Intervention Research Department 7812 Copenhagen University HospitalRigshospitalet Copenhagen Denmark
| | - Lars N. Jorgensen
- Digestive Disease Center Bispebjerg and Frederiksberg Hospital University of Copenhagen Copenhagen Denmark
| | - Robin Christensen
- Musculoskeletal Statistics Unit, The Parker Institute Bispebjerg and Frederiksberg Hospital University of Copenhagen Copenhagen Denmark
- Research Unit of Rheumatology Department of Clinical Research University of Southern DenmarkOdense University Hospital Odense Denmark
| | - Christian S. Meyhoff
- Department of Anaesthesia and Intensive Care Bispebjerg and Frederiksberg Hospital University of Copenhagen Copenhagen Denmark
- Copenhagen Center for Translational Research Bispebjerg and Frederiksberg Copenhagen University Hospital Copenhagen Denmark
- Department of Clinical Medicine University of Copenhagen Copenhagen Denmark
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Perioperative Hyperoxyphobia: Justified or Not? Benefits and Harms of Hyperoxia during Surgery. J Clin Med 2020; 9:jcm9030642. [PMID: 32121051 PMCID: PMC7141263 DOI: 10.3390/jcm9030642] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2020] [Revised: 02/18/2020] [Accepted: 02/26/2020] [Indexed: 12/12/2022] Open
Abstract
The use of an inspiratory oxygen fraction of 0.80 during surgery is a topic of ongoing debate. Opponents claim that increased oxidative stress, atelectasis, and impaired oxygen delivery due to hyperoxic vasoconstriction are detrimental. Proponents point to the beneficial effects on the incidence of surgical site infections and postoperative nausea and vomiting. Also, hyperoxygenation is thought to extend the safety margin in case of acute intraoperative emergencies. This review provides a comprehensive risk-benefit analysis for the use of perioperative hyperoxia in noncritically ill adults based on clinical evidence and supported by physiological deduction where needed. Data from the field of hyperbaric medicine, as a model of extreme hyperoxygenation, are extrapolated to the perioperative setting. We ultimately conclude that current evidence is in favour of hyperoxia in noncritically ill intubated adult surgical patients.
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Mattishent K, Thavarajah M, Sinha A, Peel A, Egger M, Solomkin J, de Jonge S, Latif A, Berenholtz S, Allegranzi B, Loke YK. Safety of 80% vs 30-35% fraction of inspired oxygen in patients undergoing surgery: a systematic review and meta-analysis. Br J Anaesth 2019; 122:311-324. [PMID: 30770049 DOI: 10.1016/j.bja.2018.11.026] [Citation(s) in RCA: 65] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Revised: 11/06/2018] [Accepted: 11/08/2018] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Evidence-based guidelines from the World Health Organization (WHO) have recommended a high (80%) fraction of inspired oxygen (FiO2) to reduce surgical site infection in adult surgical patients undergoing general anaesthesia with tracheal intubation. However, there is ongoing debate over the safety of high FiO2. We performed a systematic review to define the relative risk of clinically relevant adverse events (AE) associated with high FiO2. METHODS We reviewed potentially relevant articles from the WHO review supporting the recommendation, including an updated (July 2018) search of EMBASE and PubMed for randomised and non-randomised controlled studies reporting AE in surgical patients receiving 80% FiO2 compared with 30-35% FiO2. We assessed study quality and performed meta-analyses of risk ratios (RR) comparing 80% FiO2 against 30-35% for major complications, mortality, and intensive care admission. RESULTS We included 17 moderate-good quality trials and two non-randomised studies with serious-critical risk of bias. No evidence of harm with high FiO2 was found for major AE in the meta-analysis of randomised trials: atelectasis RR 0.91 [95% confidence interval (CI) 0.59-1.42); cardiovascular events RR 0.90 (95% CI 0.32-2.54); intensive care admission RR 0.93 (95% CI 0.7-1.12); and death during the trial RR 0.49 (95% CI 0.17-1.37). One non-randomised study reported that high FiO2 was associated with major respiratory AE [RR 1.99 (95% CI 1.72-2.31)]. CONCLUSIONS No definite signal of harm with 80% FiO2 in adult surgical patients undergoing general anaesthesia was demonstrated and there is little evidence on safety-related issues to discourage its use in this population.
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Affiliation(s)
| | | | - Ashnish Sinha
- Norwich Medical School, University of East Anglia, Norwich, UK
| | - Adam Peel
- Norwich Medical School, University of East Anglia, Norwich, UK
| | - Matthias Egger
- Institute of Social and Preventive Medicine, University of Bern, Bern, Switzerland
| | - Joseph Solomkin
- Department of Surgery, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Stijn de Jonge
- Department of Surgery, Amsterdam Gastroenterology and Metabolism, Amsterdam Infection and Immunity, Amsterdam UMC, Location AMC, University of Amsterdam, the Netherlands
| | - Asad Latif
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA; Armstrong Institute for Patient Safety and Quality, Johns Hopkins Medicine, Baltimore, MD, USA
| | - Sean Berenholtz
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA; Armstrong Institute for Patient Safety and Quality, Johns Hopkins Medicine, Baltimore, MD, USA
| | - Benedetta Allegranzi
- Infection Prevention and Control Global Unit, Service Delivery and Safety, World Health Organization, Geneva, Switzerland.
| | - Yoon Kong Loke
- Norwich Medical School, University of East Anglia, Norwich, UK
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Smit B, Smulders YM, Eringa EC, Gelissen HPMM, Girbes ARJ, de Grooth HJS, Schotman HHM, Scheffer PG, Oudemans-van Straaten HM, Spoelstra-de Man AME. Hyperoxia does not affect oxygen delivery in healthy volunteers while causing a decrease in sublingual perfusion. Microcirculation 2018; 25. [PMID: 29210137 PMCID: PMC5838560 DOI: 10.1111/micc.12433] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Accepted: 11/27/2017] [Indexed: 12/17/2022]
Abstract
Objective To determine the human dose‐response relationship between a stepwise increase in arterial oxygen tension and its associated changes in DO2 and sublingual microcirculatory perfusion. Methods Fifteen healthy volunteers breathed increasing oxygen fractions for 10 minutes to reach arterial oxygen tensions of baseline (breathing air), 20, 40, 60 kPa, and max kPa (breathing oxygen). Systemic hemodynamics were measured continuously by the volume‐clamp method. At the end of each period, the sublingual microcirculation was assessed by SDF. Results Systemic DO2 was unchanged throughout the study (Pslope = .8). PVD decreased in a sigmoidal fashion (max −15% while breathing oxygen, SD18, Pslope = .001). CI decreased linearly (max −10%, SD10, Pslope < .001) due to a reduction in HR (max −10%, SD7, Pslope = .009). There were no changes in stroke volume or MAP. Most changes became apparent above an arterial oxygen tension of 20 kPa. Conclusions In healthy volunteers, supraphysiological arterial oxygen tensions have no effect on systemic DO2. Sublingual microcirculatory PVD decreased in a dose‐dependent fashion. All hemodynamic changes appear negligible up to an arterial oxygen tension of 20 kPa.
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Affiliation(s)
- Bob Smit
- Department of Intensive Care, VU University Medical Center, Amsterdam, The Netherlands
| | - Yvo M Smulders
- Department of Internal Medicine, VU University Medical Center, Amsterdam, The Netherlands
| | - Etto C Eringa
- Department of Physiology, VU University Medical Center, Amsterdam, The Netherlands
| | - Harry P M M Gelissen
- Department of Intensive Care, VU University Medical Center, Amsterdam, The Netherlands
| | - Armand R J Girbes
- Department of Intensive Care, VU University Medical Center, Amsterdam, The Netherlands
| | - Harm-Jan S de Grooth
- Department of Intensive Care, VU University Medical Center, Amsterdam, The Netherlands
| | - Hans H M Schotman
- Department of Clinical Chemistry, VU University Medical Center, Amsterdam, The Netherlands
| | - Peter G Scheffer
- Department of Clinical Chemistry, VU University Medical Center, Amsterdam, The Netherlands
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12
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Smit B, Smulders YM, Eringa EC, Oudemans - van Straaten HM, Girbes ARJ, Wever KE, Hooijmans CR, Spoelstra - de Man AME. Effects of hyperoxia on vascular tone in animal models: systematic review and meta-analysis. Crit Care 2018; 22:189. [PMID: 30075723 PMCID: PMC6091089 DOI: 10.1186/s13054-018-2123-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2018] [Accepted: 07/09/2018] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND Arterial hyperoxia may induce vasoconstriction and reduce cardiac output, which is particularly undesirable in patients who already have compromised perfusion of vital organs. Due to the inaccessibility of vital organs in humans, vasoconstrictive effects of hyperoxia have primarily been studied in animal models. However, the results of these studies vary substantially. Here, we investigate the variation in magnitude of the hyperoxia effect among studies and explore possible sources of heterogeneity, such as vascular region and animal species. METHOD Pubmed and Embase were searched for eligible studies up to November 2017. In vivo and ex vivo animal studies reporting on vascular tone changes induced by local or systemic normobaric hyperoxia were included. Experiments with co-interventions (e.g. disease or endothelium removal) or studies focusing on lung, brain or fetal vasculature or the ductus arteriosus were not included. We extracted data pertaining to species, vascular region, blood vessel characteristics and method of hyperoxia induction. Overall effect sizes were estimated with a standardized mean difference (SMD) random effects model. RESULTS We identified a total of 60 studies, which reported data on 67 in vivo and 18 ex vivo experiments. In the in vivo studies, hyperoxia caused vasoconstriction with an SMD of - 1.42 (95% CI - 1.65 to - 1.19). Ex vivo, the overall effect size was SMD - 0.56 (95% CI - 1.09 to - 0.03). Between-study heterogeneity (I2) was high for in vivo (72%, 95% CI 62 to 85%) and ex vivo studies (86%, 95% CI 78 to 98%). In vivo, in comparison to the overall effect size, hyperoxic vasoconstriction was less pronounced in the intestines and skin (P = 0.03) but enhanced in the cremaster muscle region (P < 0.001). Increased constriction was seen in vessels 15-25 μm in diameter. Hyperoxic constriction appeared to be directly proportional to oxygen concentration. For ex vivo studies, heterogeneity could not be explained with subgroup analysis. CONCLUSION The effect of hyperoxia on vascular tone is substantially higher in vivo than ex vivo. The magnitude of the constriction is most pronounced in vessels ~ 15-25 μm in diameter and is proportional to the level of hyperoxia. Relatively increased constriction was seen in muscle vasculature, while reduced constriction was seen in the skin and intestines.
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Affiliation(s)
- Bob Smit
- Department of Intensive Care, VU University Medical Center, De Boelelaan 1117, 1007 MB Amsterdam, The Netherlands
| | - Yvo M. Smulders
- Department of Internal Medicine, VU University Medical Center, Amsterdam, The Netherlands
| | - Etto C. Eringa
- Department of Physiology, VU University Medical Center, Amsterdam, The Netherlands
| | | | - Armand R. J. Girbes
- Department of Intensive Care, VU University Medical Center, De Boelelaan 1117, 1007 MB Amsterdam, The Netherlands
| | - Kimberley E. Wever
- SYstematic Review Centre for Laboratory animal Experimentation (SYRCLE), Department for Health Evidence, Radboud Institute for Health Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Carlijn R. Hooijmans
- SYstematic Review Centre for Laboratory animal Experimentation (SYRCLE), Department for Health Evidence, Radboud Institute for Health Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
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13
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Petersen C, Wetterslev J, Meyhoff CS. Perioperative hyperoxia and post-operative cardiac complications in adults undergoing non-cardiac surgery: Systematic review protocol. Acta Anaesthesiol Scand 2018; 62:1014-1019. [PMID: 29664117 DOI: 10.1111/aas.13123] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2017] [Revised: 03/06/2018] [Accepted: 03/14/2018] [Indexed: 02/01/2023]
Abstract
BACKGROUND Oxygen therapy is used liberally for all patients undergoing anaesthesia. Recent studies have raised concerns that it may not be without complications when arterial oxygen concentrations reach supranormal concentrations (hyperoxia). Studies of oxygen therapy have raised concerns that the risk of myocardial injury and infarction is elevated in patients with hyperoxia due to vasoconstriction and formation of reactive oxygen species. Due to lack of symptoms or silent ischaemia, post-operative myocardial injury may be missed clinically. In some studies, perioperative hyperoxia has been linked to increased long-term mortality, but cardiac complications are sparsely evaluated. The aim of this review is to summarize current evidence to assess the risk and benefits of perioperative hyperoxia on post-operative cardiac complications. METHODS This systematic review will include meta-analyses and Trial Sequential Analyses. We will include randomized clinical trials with patients undergoing non-cardiac surgery if the allocation separates patients into a target of either higher (above 0.60) or lower (below 0.40) inspired oxygen fraction. To minimize the risk of systematic error, we will assess the risk of bias of the included trials using the Cochrane Risk of Bias Tool. The overall quality of evidence for each outcome will be assessed with the Grading of Recommendation, Assessment, Development and Evaluation (GRADE). DISCUSSION This systematic review will provide data on a severe, albeit rare, potential risk of oxygen therapy. We will do a trial sequential analysis to assess the robustness of results as well as help estimate the required patient size for future clinical trials.
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Affiliation(s)
- C Petersen
- Department of Anaesthesia and Intensive Care, Bispebjerg and Frederiksberg Hospital, University of Copenhagen, Copenhagen, Denmark
| | - J Wetterslev
- Copenhagen Trial Unit, Centre for Clinical Intervention Research, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
| | - C S Meyhoff
- Department of Anaesthesia and Intensive Care, Bispebjerg and Frederiksberg Hospital, University of Copenhagen, Copenhagen, Denmark
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Miller AJ, Luck JC, Kim DJK, Leuenberger UA, Aziz F, Radtka JF, Sinoway LI, Muller MD. Peripheral revascularization attenuates the exercise pressor reflex and increases coronary exercise hyperemia in peripheral arterial disease. J Appl Physiol (1985) 2018; 125:58-63. [PMID: 29648515 DOI: 10.1152/japplphysiol.01046.2017] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Peripheral arterial disease (PAD) is associated with augmented blood pressure (BP) and impaired coronary blood flow responses to exercise, which may increase cardiovascular risk. We investigated the effects of leg revascularization on the BP and coronary blood flow responses to exercise in PAD. Seventeen PAD patients (11 men, 66 ± 2 yr) performed single-leg plantar flexion exercise 24 h before and 1 mo following leg revascularization. BP and heart rate (HR) were measured continuously, and rate pressure product (systolic BP × HR) was calculated as an index of myocardial oxygen demand. Coronary blood velocity was obtained by transthoracic Doppler echocardiography in 8/17 subjects. The mean BP response to plantar flexion exercise was attenuated by leg revascularization (pre-revascularization: 15 ± 4 vs. post-revascularization: 7 ± 3 mmHg, P = 0.025). The HR response to plantar flexion was also attenuated following leg revascularization (pre-revascularization: 9 ± 1 vs. post-revascularization: 6 ± 1 beats/min, P = 0.006). The change in coronary blood velocity with exercise was greater at the post-revascularization visit: 4 ± 1 vs. pre-revascularization: -1 ± 2 cm/s ( P = 0.038), even though the change in rate pressure product was not greater following revascularization in these subjects (pre-revascularization: 2,796 ± 871 vs. post-revascularization: 1,766 ± 378 mmHg·beats/min, P = 0.082). These data suggest that leg revascularization alters reflex control of BP, HR, and coronary blood flow in response to exercise in patients with PAD. NEW & NOTEWORTHY We found that peripheral revascularization procedures lowered exercise blood pressure and improved coronary blood flow in patients with peripheral arterial disease.
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Affiliation(s)
- Amanda J Miller
- Penn State Heart and Vascular Institute, Penn State University College of Medicine , Hershey, Pennsylvania
| | - J Carter Luck
- Penn State Heart and Vascular Institute, Penn State University College of Medicine , Hershey, Pennsylvania
| | - Danielle Jin-Kwang Kim
- Penn State Heart and Vascular Institute, Penn State University College of Medicine , Hershey, Pennsylvania
| | - Urs A Leuenberger
- Penn State Heart and Vascular Institute, Penn State University College of Medicine , Hershey, Pennsylvania
| | - Faisal Aziz
- Penn State Heart and Vascular Institute, Penn State University College of Medicine , Hershey, Pennsylvania
| | - John F Radtka
- Penn State Heart and Vascular Institute, Penn State University College of Medicine , Hershey, Pennsylvania
| | - Lawrence I Sinoway
- Penn State Heart and Vascular Institute, Penn State University College of Medicine , Hershey, Pennsylvania
| | - Matthew D Muller
- Penn State Heart and Vascular Institute, Penn State University College of Medicine , Hershey, Pennsylvania
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15
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Brugniaux JV, Coombs GB, Barak OF, Dujic Z, Sekhon MS, Ainslie PN. Highs and lows of hyperoxia: physiological, performance, and clinical aspects. Am J Physiol Regul Integr Comp Physiol 2018; 315:R1-R27. [PMID: 29488785 DOI: 10.1152/ajpregu.00165.2017] [Citation(s) in RCA: 75] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Molecular oxygen (O2) is a vital element in human survival and plays a major role in a diverse range of biological and physiological processes. Although normobaric hyperoxia can increase arterial oxygen content ([Formula: see text]), it also causes vasoconstriction and hence reduces O2 delivery in various vascular beds, including the heart, skeletal muscle, and brain. Thus, a seemingly paradoxical situation exists in which the administration of oxygen may place tissues at increased risk of hypoxic stress. Nevertheless, with various degrees of effectiveness, and not without consequences, supplemental oxygen is used clinically in an attempt to correct tissue hypoxia (e.g., brain ischemia, traumatic brain injury, carbon monoxide poisoning, etc.) and chronic hypoxemia (e.g., severe COPD, etc.) and to help with wound healing, necrosis, or reperfusion injuries (e.g., compromised grafts). Hyperoxia has also been used liberally by athletes in a belief that it offers performance-enhancing benefits; such benefits also extend to hypoxemic patients both at rest and during rehabilitation. This review aims to provide a comprehensive overview of the effects of hyperoxia in humans from the "bench to bedside." The first section will focus on the basic physiological principles of partial pressure of arterial O2, [Formula: see text], and barometric pressure and how these changes lead to variation in regional O2 delivery. This review provides an overview of the evidence for and against the use of hyperoxia as an aid to enhance physical performance. The final section addresses pathophysiological concepts, clinical studies, and implications for therapy. The potential of O2 toxicity and future research directions are also considered.
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Affiliation(s)
| | - Geoff B Coombs
- Centre for Heart, Lung, and Vascular Health, University of British Columbia , Kelowna, British Columbia , Canada
| | - Otto F Barak
- Faculty of Medicine, University of Novi Sad, Novi Sad, Serbia.,Faculty of Sport and Physical Education, University of Novi Sad, Novi Sad, Serbia
| | - Zeljko Dujic
- Department of Integrative Physiology, School of Medicine, University of Split , Split , Croatia
| | - Mypinder S Sekhon
- Centre for Heart, Lung, and Vascular Health, University of British Columbia , Kelowna, British Columbia , Canada.,Division of Critical Care Medicine, Department of Medicine, Vancouver General Hospital, University of British Columbia , Vancouver, British Columbia , Canada
| | - Philip N Ainslie
- Centre for Heart, Lung, and Vascular Health, University of British Columbia , Kelowna, British Columbia , Canada
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16
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Smit B, Smulders YM, van der Wouden JC, Oudemans-van Straaten HM, Spoelstra-de Man AME. Hemodynamic effects of acute hyperoxia: systematic review and meta-analysis. CRITICAL CARE : THE OFFICIAL JOURNAL OF THE CRITICAL CARE FORUM 2018; 22:45. [PMID: 29477145 PMCID: PMC6389225 DOI: 10.1186/s13054-018-1968-2] [Citation(s) in RCA: 62] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/17/2017] [Accepted: 01/26/2018] [Indexed: 02/06/2023]
Abstract
Background In clinical practice, oxygen is generally administered to patients with the intention of increasing oxygen delivery. Supplemental oxygen may, however, cause arterial hyperoxia, which is associated with hemodynamic alterations. We performed a systematic review and meta-analysis of the literature to determine the effect of hyperoxia on central hemodynamics and oxygen delivery in healthy volunteers and cardiovascular-compromised patients. Methods PubMed and EMBASE were searched up to March 2017. Studies with adult humans investigating changes in central hemodynamics or oxygen delivery induced by acute normobaric hyperoxia were included. Studies focusing on lung, retinal, or brain parameters were not included. We extracted subject and oxygen exposure characteristics, indexed and unindexed values for heart rate, stroke volume, cardiac output, mean arterial pressure (MAP), systemic vascular resistance, and oxygen delivery during normoxia and hyperoxia. For quantitative synthesis of the data, a random-effects ratio of means (RoM) model was used. Results We identified 33 studies with 42 datasets. Study categories included healthy volunteers (n = 22 datasets), patients with coronary artery disease (CAD; n = 6), heart failure (HF; n = 6), coronary artery bypass graft (CABG; n = 3) and sepsis (n = 5). Hyperoxia (arterial oxygen tension of 234–617 mmHg) reduced cardiac output (CO) by 10–15% in both healthy volunteers (−10.2%, 95% confidence interval (CI) −12.9% to −7.3%) and CAD (−9.6%, 95% CI −12.3% to −6.9%) or HF patients (−15.2%, 95% CI −21.7% to −8.2%). No significant changes in cardiac output were seen in CABG or septic patients (−3%). Systemic vascular resistance increased remarkably in patients with heart failure (24.6%, 95% CI 19.3% to 30.1%). In healthy volunteers, and those with CAD and CABG, the effect was smaller (11–16%) and was virtually absent in patients with sepsis (4.3%, 95% CI −3.2% to 12.3%). No notable effect on MAP was found in any group (2–3%). Oxygen delivery was not altered by hyperoxia. Considerable heterogeneity existed between study results, likely due to methodological differences. Conclusions Hyperoxia may considerably decrease cardiac output and increase systemic vascular resistance, but effects differ between patient categories. Heart failure patients were the most sensitive while no hemodynamic effects were seen in septic patients. There is currently no evidence supporting the notion that oxygen supplementation increases oxygen delivery. Electronic supplementary material The online version of this article (10.1186/s13054-018-1968-2) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Bob Smit
- Department of Intensive Care, VU University Medical Center, De Boelelaan 1117, 1007, MB, Amsterdam, the Netherlands.
| | - Yvo M Smulders
- Department of Internal Medicine, VU University Medical Center, Amsterdam, the Netherlands
| | - Johannes C van der Wouden
- Department of General Practice and Elderly Care Medicine, Amsterdam Public Health research institute, VU University Medical Center, Amsterdam, the Netherlands
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17
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Vidal K, Robinson N, Ives SJ. Exercise performance and physiological responses: the potential role of redox imbalance. Physiol Rep 2017; 5:5/7/e13225. [PMID: 28364030 PMCID: PMC5392515 DOI: 10.14814/phy2.13225] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Revised: 03/01/2017] [Accepted: 03/02/2017] [Indexed: 11/24/2022] Open
Abstract
Increases in oxidative stress or decreases in antioxidant capacity, or redox imbalance, are known to alter physiological function and has been suggested to influence performance. To date, no study has sought to manipulate this balance in the same participants and observe the impact on physiological function and performance. Using a single‐blind, placebo‐controlled, and counterbalanced design, this study examined the effects of increasing free radicals, via hyperoxic exposure (FiO2 = 1.0), and/or increasing antioxidant capacity, through consuming an antioxidant cocktail (AOC; vitamin‐C, vitamin‐E, α‐lipoic acid), on 5‐kilometer (km) cycling time‐trial performance, and the physiological and fatigue responses in healthy college‐aged males. Hyperoxic exposure prior to the 5 km TT had no effect on performance, fatigue, or the physiological responses to exercise. The AOC significantly reduced average power output (222 ± 11 vs. 214 ± 12 W), increased 5 km time (516 ± 17 vs. 533 ± 18 sec), suppressed ventilation (VE; 116 ± 5 vs. 109 ± 13 L/min), despite similar oxygen consumption (VO2; 43.1 ± 0.8 vs. 44.9 ± 0.2 mL/kg per min), decreased VE/VO2 (35.9 ± 2.0 vs. 32.3 ± 1.5 L/min), reduced economy (VO2/W; 0.20 ± 0.01 vs. 0.22 ± 0.01), increased blood lactate (10 ± 0.7 vs. 11 ± 0.7 mmol), and perception of fatigue (RPE; 7.39 ± 0.4 vs. 7.60 ± 0.3) at the end of the TT, as compared to placebo (main effect, placebo vs. AOC, respectively). Our data demonstrate that prior to exercise, ingesting an AOC, but not exposure to hyperoxia, likely disrupts the delicate balance between pro‐ and antioxidant forces, which negatively impacts ventilation, blood lactate, economy, perception of fatigue, and performance (power output and 5 km time) in young healthy males. Thus, caution is warranted in athletes taking excess exogenous antioxidants.
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Affiliation(s)
- Kavey Vidal
- Department of Health and Exercise Sciences, Skidmore College, Saratoga Springs, New York
| | - Nathaniel Robinson
- Department of Health and Exercise Sciences, Skidmore College, Saratoga Springs, New York
| | - Stephen J Ives
- Department of Health and Exercise Sciences, Skidmore College, Saratoga Springs, New York
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18
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Beaudin AE, Hartmann SE, Pun M, Poulin MJ. Human cerebral blood flow control during hypoxia: focus on chronic pulmonary obstructive disease and obstructive sleep apnea. J Appl Physiol (1985) 2017; 123:1350-1361. [DOI: 10.1152/japplphysiol.00352.2017] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2017] [Revised: 08/01/2017] [Accepted: 08/07/2017] [Indexed: 01/06/2023] Open
Abstract
The brain is a vital organ that relies on a constant and adequate blood flow to match oxygen and glucose delivery with the local metabolic demands of active neurons. Thus exquisite regulation of cerebral blood flow (CBF) is particularly important under hypoxic conditions to prevent a detrimental decrease in the partial pressure of oxygen within the brain tissues. Cerebrovascular sensitivity to hypoxia, assessed as the change in CBF during a hypoxic challenge, represents the capacity of cerebral vessels to respond to, and compensate for, a reduced oxygen supply, and has been shown to be impaired or blunted in a number of conditions. For instance, this is observed with aging, and in clinical conditions such as untreated obstructive sleep apnea (OSA) and in healthy humans exposed to intermittent hypoxia. This review will 1) provide a brief overview of cerebral blood flow regulation and results of pharmacological intervention studies which we have performed to better elucidate the basic mechanisms of cerebrovascular regulation in humans; and 2) present data from studies in clinical and healthy populations, using a translational physiology approach, to investigate human CBF control during hypoxia. Results from studies in patients with chronic obstructive pulmonary disease and OSA will be presented to identify the effects of the disease processes on cerebrovascular sensitivity to hypoxia. Data emerging from experimental human models of intermittent hypoxia during wakefulness will also be reviewed to highlight the effects of intermittent hypoxia on the brain.
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Affiliation(s)
- Andrew E. Beaudin
- Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
- Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Sara E. Hartmann
- Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
- Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Matiram Pun
- Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
- Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Marc J. Poulin
- Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
- Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
- Department of Clinical Neurosciences, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
- Libin Cardiovascular Institute of Alberta, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada; and
- Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada
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19
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Vargas Pelaez AF, Gao Z, Ahmad TA, Leuenberger UA, Proctor DN, Maman SR, Muller MD. Effect of adrenergic agonists on coronary blood flow: a laboratory study in healthy volunteers. Physiol Rep 2016; 4:4/10/e12806. [PMID: 27225628 PMCID: PMC4886172 DOI: 10.14814/phy2.12806] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2016] [Accepted: 04/30/2016] [Indexed: 12/20/2022] Open
Abstract
Myocardial oxygen supply and demand mismatch is fundamental to the pathophysiology of ischemia and infarction. The sympathetic nervous system, through α‐adrenergic receptors and β‐adrenergic receptors, influences both myocardial oxygen supply and demand. In animal models, mechanistic studies have established that adrenergic receptors contribute to coronary vascular tone. The purpose of this laboratory study was to noninvasively quantify coronary responses to adrenergic receptor stimulation in humans. Fourteen healthy volunteers (11 men and 3 women) performed isometric handgrip exercise to fatigue followed by intravenous infusion of isoproterenol. A subset of individuals also received infusions of phenylephrine (n = 6), terbutaline (n = 10), and epinephrine (n = 4); all dosages were based on fat‐free mass and were infused slowly to achieve steady‐state. The left anterior descending coronary artery was visualized using Doppler echocardiography. Beat‐by‐beat heart rate (HR), blood pressure (BP), peak diastolic coronary velocity (CBVpeak), and coronary velocity time integral were calculated. Data are presented as M ± SD. Isometric handgrip elicited significant increases in BP, HR, and CBVpeak (from 23.3 ± 5.3 to 34.5 ± 9.9 cm/sec). Isoproterenol raised HR and CBVpeak (from 22.6 ± 4.8 to 43.9 ± 12.4 cm/sec). Terbutaline and epinephrine evoked coronary hyperemia whereas phenylephrine did not significantly alter CBVpeak. Different indices of coronary hyperemia (changes in CBVpeak and velocity time integral) were significantly correlated (R = 0.803). The current data indicate that coronary hyperemia occurs in healthy humans in response to isometric handgrip exercise and low‐dose, steady‐state infusions of isoproterenol, terbutaline, and epinephrine. The contribution of β1 versus β2 receptors to coronary hyperemia remains to be determined. In this echocardiographic study, we demonstrate that coronary blood flow increases when β‐adrenergic receptors are stimulated (i.e., during exercise and different intravenous infusions). Our infusion paradigms and beat‐by‐beat imaging methodologies can be used in future studies to evaluate age‐, sex‐, and disease‐ differences in adrenergic control of coronary blood flow.
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Affiliation(s)
- Alvaro F Vargas Pelaez
- Penn State Heart and Vascular Institute, Penn State University College of Medicine, Hershey, Pennsylvania
| | - Zhaohui Gao
- Penn State Heart and Vascular Institute, Penn State University College of Medicine, Hershey, Pennsylvania
| | - Tariq A Ahmad
- Division of General Internal Medicine, Penn State University College of Medicine, Hershey, Pennsylvania
| | - Urs A Leuenberger
- Penn State Heart and Vascular Institute, Penn State University College of Medicine, Hershey, Pennsylvania
| | - David N Proctor
- Department of Kinesiology, Noll Laboratory, The Pennsylvania State University, University Park, Pennsylvania
| | - Stephan R Maman
- Penn State Heart and Vascular Institute, Penn State University College of Medicine, Hershey, Pennsylvania
| | - Matthew D Muller
- Penn State Heart and Vascular Institute, Penn State University College of Medicine, Hershey, Pennsylvania
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21
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Ross AJ, Gao Z, Luck JC, Blaha CA, Cauffman AE, Aziz F, Radtka JF, Proctor DN, Leuenberger UA, Sinoway LI, Muller MD. Coronary Exercise Hyperemia Is Impaired in Patients with Peripheral Arterial Disease. Ann Vasc Surg 2016; 38:260-267. [PMID: 27575303 DOI: 10.1016/j.avsg.2016.05.135] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Revised: 05/23/2016] [Accepted: 05/27/2016] [Indexed: 01/19/2023]
Abstract
BACKGROUND Peripheral arterial disease (PAD) is an atherosclerotic vascular disease that affects over 200 million people worldwide. The hallmark of PAD is ischemic leg pain and this condition is also associated with an augmented blood pressure response to exercise, impaired vascular function, and high risk of myocardial infarction and cardiovascular mortality. In this study, we tested the hypothesis that coronary exercise hyperemia is impaired in PAD. METHODS Twelve patients with PAD and no overt coronary disease (65 ± 2 years, 7 men) and 15 healthy control subjects (64 ± 2 years, 9 men) performed supine plantar flexion exercise (30 contractions/min, increasing workload). A subset of subjects (n = 7 PAD, n = 8 healthy) also performed isometric handgrip exercise (40% of maximum voluntary contraction to fatigue). Coronary blood velocity in the left anterior descending artery was measured by transthoracic Doppler echocardiography; blood pressure and heart rate were monitored continuously. RESULTS Coronary blood velocity responses to 4 min of plantar flexion exercise (PAD: Δ2.4 ± 1.2, healthy: Δ6.0 ± 1.6 cm/sec, P = 0.039) and isometric handgrip exercise (PAD: Δ8.3 ± 4.2, healthy: Δ16.9 ± 3.6, P = 0.033) were attenuated in PAD patients. CONCLUSION These data indicate that coronary exercise hyperemia is impaired in PAD, which may predispose these patients to myocardial ischemia.
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Affiliation(s)
- Amanda J Ross
- Penn State Heart and Vascular Institute, Penn State University College of Medicine, Hershey, PA
| | - Zhaohui Gao
- Penn State Heart and Vascular Institute, Penn State University College of Medicine, Hershey, PA
| | - Jonathan Carter Luck
- Penn State Heart and Vascular Institute, Penn State University College of Medicine, Hershey, PA
| | - Cheryl A Blaha
- Penn State Heart and Vascular Institute, Penn State University College of Medicine, Hershey, PA
| | - Aimee E Cauffman
- Penn State Heart and Vascular Institute, Penn State University College of Medicine, Hershey, PA
| | - Faisal Aziz
- Penn State Heart and Vascular Institute, Penn State University College of Medicine, Hershey, PA
| | - John F Radtka
- Penn State Heart and Vascular Institute, Penn State University College of Medicine, Hershey, PA
| | - David N Proctor
- Department of Kinesiology, Noll Laboratory, The Pennsylvania State University, State College, PA
| | - Urs A Leuenberger
- Penn State Heart and Vascular Institute, Penn State University College of Medicine, Hershey, PA
| | - Lawrence I Sinoway
- Penn State Heart and Vascular Institute, Penn State University College of Medicine, Hershey, PA
| | - Matthew D Muller
- Penn State Heart and Vascular Institute, Penn State University College of Medicine, Hershey, PA.
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Smit B, Smulders YM, de Waard MC, Boer C, Vonk ABA, Veerhoek D, Kamminga S, de Grooth HJS, García-Vallejo JJ, Musters RJP, Girbes ARJ, Oudemans-van Straaten HM, Spoelstra-de Man AME. Moderate hyperoxic versus near-physiological oxygen targets during and after coronary artery bypass surgery: a randomised controlled trial. CRITICAL CARE : THE OFFICIAL JOURNAL OF THE CRITICAL CARE FORUM 2016; 20:55. [PMID: 26968380 PMCID: PMC4788916 DOI: 10.1186/s13054-016-1240-6] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Accepted: 02/10/2016] [Indexed: 01/21/2023]
Abstract
Background The safety of perioperative hyperoxia is currently unclear. Previous studies in patients undergoing coronary artery bypass surgery suggest reduced myocardial damage when avoiding extreme perioperative hyperoxia (>400 mmHg). In this study we investigated whether an oxygenation strategy from moderate hyperoxia to a near-physiological oxygen tension reduces myocardial damage and improves haemodynamics, organ dysfunction and oxidative stress. Methods This was a single-blind, single-centre, open-label, randomised controlled trial in patients undergoing elective coronary artery bypass surgery. Fifty patients were randomised to a partial pressure of oxygen in arterial blood (PaO2) target of 200–220 mmHg during cardiopulmonary bypass and 130–150 mmHg during intensive care unit (ICU) admission (control group) versus lower targets of 130–150 mmHg during cardiopulmonary bypass and 80–100 mmHg at the ICU (conservative group). Primary outcome was myocardial injury (CK-MB and Troponin-T) at ICU admission and 2, 6 and 12 hours thereafter. Results Weighted PaO2 during cardiopulmonary bypass was 220 mmHg (interquartile range (IQR) 211–233) vs. 157 (151–162) in the control and conservative group, respectively (P < 0.0001). During ICU admission, weighted PaO2 was 107 mmHg (86–141) vs. 90 (84–98) (P = 0.03), respectively. Area under the curve of CK-MB was median 23.5 μg/L/h (IQR 18.4–28.1) vs. 21.5 (15.8–26.6) (P = 0.35) and 0.30 μg/L/h (0.25–0.44) vs. 0.39 (0.24–0.43) (P = 0.81) for Troponin-T. Cardiac index, systemic vascular resistance index, creatinine, lactate and F2-isoprostane levels were not different between groups. Conclusions Compared to moderate hyperoxia, a near-physiological oxygen strategy does not reduce myocardial damage in patients undergoing coronary artery bypass surgery. Conservative oxygen administration was not associated with increased lactate levels or hypoxic events. Trial registration Netherlands Trial Registry NTR4375, registered on 30 January 2014 Electronic supplementary material The online version of this article (doi:10.1186/s13054-016-1240-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Bob Smit
- Department of Intensive Care, VU University Medical Center, Amsterdam, The Netherlands.
| | - Yvo M Smulders
- Department of Internal Medicine, VU University Medical Center, Amsterdam, The Netherlands
| | - Monique C de Waard
- Department of Intensive Care, VU University Medical Center, Amsterdam, The Netherlands
| | - Christa Boer
- Department of Anaesthesiology, VU University Medical Center, Amsterdam, The Netherlands
| | - Alexander B A Vonk
- Department of Cardiothoracic Surgery, VU University Medical Center, Amsterdam, The Netherlands
| | - Dennis Veerhoek
- Department of Cardiothoracic Surgery, VU University Medical Center, Amsterdam, The Netherlands
| | - Suzanne Kamminga
- Department of Anaesthesiology, VU University Medical Center, Amsterdam, The Netherlands
| | - Harm-Jan S de Grooth
- Department of Intensive Care, VU University Medical Center, Amsterdam, The Netherlands
| | - Juan J García-Vallejo
- Department of Molecular Cell Biology & Immunology, VU University Medical Center, Amsterdam, The Netherlands
| | - Rene J P Musters
- Department of Physiology, VU University Medical Center, Amsterdam, The Netherlands
| | - Armand R J Girbes
- Department of Intensive Care, VU University Medical Center, Amsterdam, The Netherlands
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Panwar R, Hardie M, Bellomo R, Barrot L, Eastwood GM, Young PJ, Capellier G, Harrigan PWJ, Bailey M. Conservative versus Liberal Oxygenation Targets for Mechanically Ventilated Patients. A Pilot Multicenter Randomized Controlled Trial. Am J Respir Crit Care Med 2016; 193:43-51. [DOI: 10.1164/rccm.201505-1019oc] [Citation(s) in RCA: 175] [Impact Index Per Article: 21.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
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Chen N, Yin S, Song X, Fan L, Hu H. Vitamin B₂ Sensitizes Cancer Cells to Vitamin-C-Induced Cell Death via Modulation of Akt and Bad Phosphorylation. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2015; 63:6739-6748. [PMID: 26165392 DOI: 10.1021/acs.jafc.5b01909] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Vitamin C is an essential dietary nutrient that has a variety of biological functions. Recent studies have provided promising evidence for its additional health benefits, including anticancer activity. Vitamin B2, another essential dietary nutrient, often coexists with vitamin C in some fruits, vegetables, or dietary supplements. The objective of the present study is to determine whether the combination of vitamin C and B2 can achieve a synergistic anticancer activity. MDA-MB-231, MCF-7, and A549 cells were employed to evaluate the combinatory effects of vitamin C and B2. We found that the combination of vitamin C and B2 resulted in a synergistic cell death induction in all cell lines tested. Further mechanistic investigations revealed that vitamin B2 sensitized cancer cells to vitamin C through inhibition of Akt and Bad phosphorylation. Our findings identified vitamin B2 as a promising sensitizer for improving the efficacy of vitamin-C-based cancer chemoprevention and chemotherapy.
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Affiliation(s)
- Ni Chen
- ‡Department of Nutrition and Health, College of Food Science and Nutritional Engineering, China Agricultural University, No. 17 Qinghua East Road, Haidian District, Beijing 100083, People's Republic of China
| | - Shutao Yin
- ‡Department of Nutrition and Health, College of Food Science and Nutritional Engineering, China Agricultural University, No. 17 Qinghua East Road, Haidian District, Beijing 100083, People's Republic of China
| | - Xinhua Song
- ‡Department of Nutrition and Health, College of Food Science and Nutritional Engineering, China Agricultural University, No. 17 Qinghua East Road, Haidian District, Beijing 100083, People's Republic of China
| | - Lihong Fan
- §College of Veterinary Medicine, China Agricultural University, No. 2 Yunamingyuan West Road, Haidian District, Beijing 100193, People's Republic of China
| | - Hongbo Hu
- ‡Department of Nutrition and Health, College of Food Science and Nutritional Engineering, China Agricultural University, No. 17 Qinghua East Road, Haidian District, Beijing 100083, People's Republic of China
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25
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Affiliation(s)
- K O Pryor
- Department of Anesthesiology, Weill Cornell Medical College, 525 East 68th Street, New York, NY 10065, USA
| | - M M Berger
- Department of Anesthesiology, Perioperative and General Critical Care Medicine, Salzburg General Hospital, Paracelsus Medical University, Müllner Haupstraße 48, Salzburg 5020, Austria
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Lott ME, Slocomb JE, Gao Z, Gabbay RA, Quillen D, Gardner TW, Bettermann K. Impaired coronary and retinal vasomotor function to hyperoxia in Individuals with Type 2 diabetes. Microvasc Res 2015; 101:1-7. [PMID: 26002545 DOI: 10.1016/j.mvr.2015.05.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Revised: 04/21/2015] [Accepted: 05/12/2015] [Indexed: 11/30/2022]
Abstract
PURPOSE Adults with diabetes are at a high risk of developing coronary heart disease. The purpose of this study was to assess coronary artery vascular function non-invasively in individuals with and without Type 2 diabetes and to compare these coronary responses to another microvascular bed (i.e. retina). We hypothesized that individuals with diabetes would have impaired coronary reactivity and that these impairments would be associated with impairments in retinal reactivity. METHODS Coronary blood velocity (Transthoracic Doppler Echocardiography) and retinal diameters (Dynamic Vessel Analyzer) were measured continuously during five minutes of breathing 100% oxygen (i.e. hyperoxia) in 15 persons with Type 2 diabetes and 15 age-matched control subjects. Using fundus photographs, retinal vascular calibers were also measured (central retinal arteriole and venule equivalents). RESULTS Individuals with diabetes compared to controls had impaired coronary (-2.34±16.64% vs. -14.27±10.58%, P=0.03) and retinal (arteriole: -0.04±3.34% vs. -3.65±5.07%, P=0.03; venule: -1.65±3.68% vs. -5.23±5.47%, P=0.05) vasoconstrictor responses to hyperoxia, and smaller central arteriole-venule equivalent ratios (0.83±0.07 vs. 0.90±0.07, P=0.014). Coronary reactivity was associated with central retinal arteriole equivalents (r=-0.516, P=0.005) and retinal venular reactivity (r=0.387, P=0.034). CONCLUSION Diabetes impairs coronary and retinal microvascular function to hyperoxia. Impaired vasoconstrictor responses may be part of a systemic diabetic vasculopathy, which may contribute to adverse cardiovascular events in individuals with diabetes.
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Affiliation(s)
- Mary E Lott
- Penn State Hershey Medical Center, Heart and Vascular Institute, Hershey, PA 17033, USA.
| | - Julia E Slocomb
- John Hopkins University, Department of Biology, Baltimore, MD 21218, USA
| | - Zhaohui Gao
- Penn State Hershey Medical Center, Heart and Vascular Institute, Hershey, PA 17033, USA
| | - Robert A Gabbay
- Joslin Diabetes Center, Harvard Medical School, Boston, MA 02116, USA
| | - David Quillen
- Penn State Hershey Medical Center, Department of Ophthalmology, Hershey, PA 17033, USA
| | - Thomas W Gardner
- University of Michigan, Kellogg Eye Center, Ann Arbor, MI 48105, USA
| | - Kerstin Bettermann
- Penn State Hershey Medical Center, Department of Neurology, Hershey, PA 17033, USA
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Randolph BJ, Patel HM, Muller MD. Ascorbic acid attenuates the pressor response to voluntary apnea in postmenopausal women. Physiol Rep 2015; 3:3/4/e12384. [PMID: 25907792 PMCID: PMC4425983 DOI: 10.14814/phy2.12384] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
We recently demonstrated that postmenopausal women have an augmented blood pressure response to voluntary apnea compared to premenopausal women. Both obstructive sleep apnea (OSA) and healthy aging are associated with increased oxidative stress, which may impair cardiovascular function. Restoring physiological responses could have clinical relevance since transient surges in blood pressure are thought to be an important stimulus for end-organ damage in aging and disease. We tested the hypothesis that acute antioxidant infusion improves physiological responses to voluntary apnea in healthy postmenopausal women (n = 8, 64 ± 2 year). We measured beat-by-beat mean arterial pressure (MAP), heart rate (HR), and brachial artery blood flow velocity (BBFV, Doppler ultrasound) following intravenous infusion of normal saline and ascorbic acid (∼3500 mg). Subjects performed maximal voluntary end-expiratory apneas and changes (Δ) from baseline were compared between infusions. The breath hold duration and oxygen saturation nadir were similar between saline (29 ± 6 sec, 94 ± 1%) and ascorbic acid (29 ± 5 sec, 94 ± 1%). Ascorbic acid attenuated the pressor response to voluntary apnea (ΔMAP: 6 ± 2 mmHg) as compared to saline (ΔMAP: 12 ± 2 mmHg, P = 0.034) and also attenuated forearm vasoconstriction (ΔBBFV: 4 ± 9 vs. −12 ± 7%, P = 0.049) but did not affect ΔHR. We conclude that ascorbic acid lowers the blood pressure response to voluntary apnea in postmenopausal women by inhibiting vasoconstriction in the limb vasculature. Whether ascorbic acid has similar effects in OSA patients remains to be prospectively tested.
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Affiliation(s)
- Brittney J. Randolph
- Pennsylvania State University College of Medicine; Penn State Hershey Heart and Vascular Institute; Hershey Pennsylvania
| | - Hardikkumar M. Patel
- Pennsylvania State University College of Medicine; Penn State Hershey Heart and Vascular Institute; Hershey Pennsylvania
| | - Matthew D. Muller
- Pennsylvania State University College of Medicine; Penn State Hershey Heart and Vascular Institute; Hershey Pennsylvania
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Heffernan MJ, Muller MD. Do peripheral and/or central chemoreflexes influence skin blood flow in humans? Physiol Rep 2014; 2:2/10/e12181. [PMID: 25344478 PMCID: PMC4254106 DOI: 10.14814/phy2.12181] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2014] [Accepted: 09/30/2014] [Indexed: 06/04/2023] Open
Abstract
Voluntary apnea activates the central and peripheral chemoreceptors, leading to a rise in sympathetic nerve activity and limb vasoconstriction (i.e., brachial blood flow velocity and forearm cutaneous vascular conductance decrease to a similar extent). Whether peripheral and/or central chemoreceptors contribute to the cutaneous vasoconstrictor response remains unknown. We performed three separate experiments in healthy young men to test the following three hypotheses. First, inhibition of peripheral chemoreceptors with brief hyperoxia inhalation (100% O2) would attenuate the cutaneous vasoconstrictor response to voluntary apnea. Second, activation of the peripheral chemoreceptors with 5 min of hypoxia (10% O2, 90% N2) would augment the cutaneous vasoconstrictor response to voluntary apnea. Third, activation of the central chemoreceptors with 5 min of hypercapnia (7% CO2, 30% O2, 63% N2) would have no influence on cutaneous responses to voluntary apnea. Studies were performed in the supine posture with skin temperature maintained at thermoneutral levels. Beat-by-beat blood pressure, heart rate, brachial blood flow velocity, and cutaneous vascular conductance were measured and changes from baseline were compared between treatments. Relative to room air, hyperoxia attenuated the vasoconstrictor response to voluntary apnea in both muscle (-16 ± 10 vs. -40 ± 12%, P = 0.023) and skin (-14 ± 6 vs. -24 ± 5%, P = 0.033). Neither hypoxia nor hypercapnia had significant effects on cutaneous responses to apnea. These data indicate that skin blood flow is controlled by the peripheral chemoreceptors but not the central chemoreceptors.
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Affiliation(s)
- Matthew J. Heffernan
- Pennsylvania State University College of Medicine, Penn State Hershey Heart and Vascular Institute, Hershey, Pennsylvania
| | - Matthew D. Muller
- Pennsylvania State University College of Medicine, Penn State Hershey Heart and Vascular Institute, Hershey, Pennsylvania
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29
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Ross AJ, Gao Z, Pollock JP, Leuenberger UA, Sinoway LI, Muller MD. β-Adrenergic receptor blockade impairs coronary exercise hyperemia in young men but not older men. Am J Physiol Heart Circ Physiol 2014; 307:H1497-503. [PMID: 25239806 DOI: 10.1152/ajpheart.00584.2014] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Patients with coronary artery disease have attenuated coronary vasodilator responses to physiological stress, which is partially attributed to a β-adrenergic receptor (β-AR)-mediated mechanisms. Whether β-ARs contribute to impaired coronary vasodilation seen with healthy aging is unknown. The purpose of this study was to investigate the role of β-ARs in coronary exercise hyperemia in healthy humans. Six young men (26 ± 1 yr) and seven older men (67 ± 4 yr) performed isometric handgrip exercise at 30% maximal voluntary contraction for 2 min after receiving intravenous propranolol, a β-AR antagonist, and no treatment. Isoproterenol, a β-AR agonist, was infused to confirm the β-AR blockade. Blood pressure and heart rate were monitored continuously, and coronary blood flow velocity (CBV, left anterior descending artery) was measured by transthoracic Doppler echocardiography. Older men had an attenuated ΔCBV to isometric exercise (3.8 ± 1.3 vs. 9.7 ± 2.1 cm/s, P = 0.02) compared with young men. Propranolol decreased the ΔCBV at peak handgrip exercise in young men (9.7 ± 2.1 vs. 2.7 ± 0.9 cm/s, P = 0.008). However, propranolol had no effect on ΔCBV in older men (3.8 ± 1.3 vs. 4.2 ± 1.9 cm/s, P = 0.9). Older men also had attenuated coronary hyperemia to low-dose isoproterenol. These data indicate that β-AR control of coronary blood flow is impaired in healthy older men.
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Affiliation(s)
- Amanda J Ross
- Pennsylvania State University College of Medicine, Penn State Hershey Heart and Vascular Institute, Hershey, Pennsylvania
| | - Zhaohui Gao
- Pennsylvania State University College of Medicine, Penn State Hershey Heart and Vascular Institute, Hershey, Pennsylvania
| | - Jonathan P Pollock
- Pennsylvania State University College of Medicine, Penn State Hershey Heart and Vascular Institute, Hershey, Pennsylvania
| | - Urs A Leuenberger
- Pennsylvania State University College of Medicine, Penn State Hershey Heart and Vascular Institute, Hershey, Pennsylvania
| | - Lawrence I Sinoway
- Pennsylvania State University College of Medicine, Penn State Hershey Heart and Vascular Institute, Hershey, Pennsylvania
| | - Matthew D Muller
- Pennsylvania State University College of Medicine, Penn State Hershey Heart and Vascular Institute, Hershey, Pennsylvania
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Vucinovic Z, Duplancic D, Seselja-Perisin A, Kukoc-Modun L, Gunjaca G, Radman M, Vukovic J, Tsikas D, Poljak K, Modun D. Acute application of antioxidants protects against hyperoxia-induced reduction of plasma nitrite concentration. Clin Physiol Funct Imaging 2014; 35:76-80. [PMID: 24863414 DOI: 10.1111/cpf.12169] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2014] [Accepted: 04/28/2014] [Indexed: 11/29/2022]
Abstract
We investigated the effects of acute intake of antioxidants on hyperoxia-induced oxidative stress, reduction of plasma nitrite and change in arterial stiffness. Twelve healthy males randomly consumed either placebo or an oral antioxidant cocktail (vitamin C, 1000 mg; vitamin E, 600 IU; alpha-lipoic acid, 600 mg). Every therapy was consumed once, a week apart, in a cross-over design, 30 min before the experiment. The volunteers breathed 100% normobaric oxygen between 30th and 60th min of 1-h study protocol. Plasma levels of nitrite, lipid peroxides (LOOH) and vitamin C, arterial stiffness (indicated by augmentation index, AIx) and arterial oxygen (Ptc O2 ) pressure were measured before and after hyperoxia. Exposure to oxygen caused a similar increase of Ptc O2 in both placebo and antioxidants groups, confirming comparable exposure to hyperoxia (438 ± 100 versus 455 ± 83 mm Hg). Vitamin C was increased in the antioxidants group confirming successful application of antioxidants (69 ± 14 versus 57 ± 15 μm). Hyperoxia resulted in increased AIx and LOOH and decreased nitrite in placebo (-32 ± 11 versus -47 ± 13%, 72 ± 7 versus 62 ± 6 μm H2 O2 and 758 ± 184 versus 920 ± 191 nm, respectively), but not in the antioxidants group (-42 ± 13 versus -50 ± 13%, 64 ± 9 versus 61 ± 8 μm H2 O2 and 847 ± 156 versus 936 ± 201 nm, respectively). The acute intake of selected antioxidants was effective in preserving bioavailabity of ˙NO and vascular function, against hyperoxia-induced oxidative stress.
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Affiliation(s)
- Zoran Vucinovic
- Department of Internal Medicine, University Hospital Split, Split, Croatia
| | - Darko Duplancic
- Department of Internal Medicine, University Hospital Split, Split, Croatia
| | - Ana Seselja-Perisin
- Department of Pharmacology, University of Split School of Medicine, Split, Croatia
| | - Lea Kukoc-Modun
- Department of Analytical Chemistry, Faculty of Chemistry and Technology, University of Split, Split, Croatia
| | - Grgo Gunjaca
- Department of Pharmacology, University of Split School of Medicine, Split, Croatia
| | - Maja Radman
- Department of Internal Medicine, University Hospital Split, Split, Croatia
| | - Jonatan Vukovic
- Department of Internal Medicine, University Hospital Split, Split, Croatia
| | - Dimitrios Tsikas
- Institute of Clinical Pharmacology, Hannover Medical School, Hannover, Germany
| | - Kolja Poljak
- Department of Otorhinolaryngology, University Hospital Split, Split, Croatia
| | - Darko Modun
- Department of Pharmacology, University of Split School of Medicine, Split, Croatia
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Muller MD, Gao Z, McQuillan PM, Leuenberger UA, Sinoway LI. Coronary responses to cold air inhalation following afferent and efferent blockade. Am J Physiol Heart Circ Physiol 2014; 307:H228-35. [PMID: 24816257 DOI: 10.1152/ajpheart.00174.2014] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Cardiac ischemia and angina pectoris are commonly experienced during exertion in a cold environment. In the current study we tested the hypotheses that oropharyngeal afferent blockade (i.e., local anesthesia of the upper airway with lidocaine) as well as systemic β-adrenergic receptor blockade (i.e., intravenous propranolol) would improve the balance between myocardial oxygen supply and demand in response to the combined stimulus of cold air inhalation (-15 to -30°C) and isometric handgrip exercise (Cold + Grip). Young healthy subjects underwent Cold + Grip following lidocaine, propranolol, and control (no drug). Heart rate, blood pressure, and coronary blood flow velocity (CBV, from Doppler echocardiography) were continuously measured. Rate-pressure product (RPP) was calculated, and changes from baseline were compared between treatments. The change in RPP at the end of Cold + Grip was not different between lidocaine (2,441 ± 376) and control conditions (3,159 ± 626); CBV responses were also not different between treatments. With propranolol, heart rate (8 ± 1 vs. 14 ± 3 beats/min) and RPP responses to Cold + Grip were significantly attenuated. However, at peak exercise propranolol also resulted in a smaller ΔCBV (1.4 ± 0.8 vs. 5.3 ± 1.4 cm/s, P = 0.035), such that the relationship between coronary flow and cardiac metabolism was impaired under propranolol (0.43 ± 0.37 vs. 2.1 ± 0.63 arbitrary units). These data suggest that cold air breathing and isometric exercise significantly influence efferent control of coronary blood flow. Additionally, β-adrenergic vasodilation may play a significant role in coronary regulation during exercise.
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Affiliation(s)
- Matthew D Muller
- Pennsylvania State University College of Medicine, Penn State Hershey Heart and Vascular Institute, Hershey, Pennsylvania
| | - Zhaohui Gao
- Pennsylvania State University College of Medicine, Penn State Hershey Heart and Vascular Institute, Hershey, Pennsylvania
| | - Patrick M McQuillan
- Pennsylvania State University College of Medicine, Penn State Hershey Heart and Vascular Institute, Hershey, Pennsylvania
| | - Urs A Leuenberger
- Pennsylvania State University College of Medicine, Penn State Hershey Heart and Vascular Institute, Hershey, Pennsylvania
| | - Lawrence I Sinoway
- Pennsylvania State University College of Medicine, Penn State Hershey Heart and Vascular Institute, Hershey, Pennsylvania
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Muller MD, Gao Z, Patel HM, Heffernan MJ, Leuenberger UA, Sinoway LI. β-Adrenergic blockade enhances coronary vasoconstrictor response to forehead cooling. Am J Physiol Heart Circ Physiol 2014; 306:H910-7. [PMID: 24441550 DOI: 10.1152/ajpheart.00787.2013] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Forehead cooling activates the sympathetic nervous system and can trigger angina pectoris in susceptible individuals. However, the effect of forehead cooling on coronary blood flow velocity (CBV) is not well understood. In this human experiment, we tested the hypotheses that forehead cooling reduces CBV (i.e., coronary vasoconstriction) and that this vasoconstrictor effect would be enhanced under systemic β-adrenergic blockade. A total of 30 healthy subjects (age range, 23-79 years) underwent Doppler echocardiography evaluation of CBV in response to 60 s of forehead cooling (1°C ice bag on forehead). A subset of subjects (n = 10) also underwent the procedures after an intravenous infusion of propranolol. Rate pressure product (RPP) was used as an index of myocardial oxygen demand. Consistent with our first hypothesis, forehead cooling reduced CBV from 19.5 ± 0.7 to 17.5 ± 0.8 cm/s (P < 0.001), whereas mean arterial pressure increased by 11 ± 2 mmHg (P < 0.001). Consistent with our second hypothesis, forehead cooling reduced CBV under propranolol despite a significant rise in RPP. The current studies indicate that forehead cooling elicits a sympathetically mediated pressor response and a reduction in CBV, and this effect is augmented under β-blockade. The results are consistent with sympathetic activation of β-receptor coronary vasodilation in humans, as has been demonstrated in animals.
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Affiliation(s)
- Matthew D Muller
- Pennsylvania State University College of Medicine, Pennsylvania State Hershey Heart and Vascular Institute, Hershey, Pennsylvania
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Gao Z, Muller MD, Sinoway LI, Leuenberger UA. Intravenous phentolamine abolishes coronary vasoconstriction in response to mild central hypovolemia. J Appl Physiol (1985) 2013; 116:216-21. [PMID: 24311747 DOI: 10.1152/japplphysiol.01048.2013] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Animal studies indicate alpha-adrenergic coronary vasoconstriction helps maintain left ventricular function during physiological stress. Whether this process occurs in humans is unknown. In the current study, we used transthoracic Doppler echocardiography to test the effect of lower body negative pressure (LBNP) on coronary blood flow velocity (CBV, left anterior descending coronary artery) and myocardial function in eight young healthy subjects before and after systemic infusion of phentolamine, a nonselective alpha blocker. Heart rate (HR) and blood pressure (BP) were monitored on a beat-by-beat basis. Peak diastolic CBV and myocardial systolic and diastolic tissue velocities (Sm and Em), were quantified at baseline, and at -5 mmHg, -10 mmHg, and -15 mmHg LBNP. Coronary vascular resistance index (CVRI) was calculated as the quotient of diastolic BP and CBV. Phentolamine reduced baseline diastolic BP and increased HR but did not affect the reflex adjustments to LBNP. The reduction in CBV due to LBNP was blunted by phentolamine at -10 mmHg and -15 mmHg. Importantly, the increase in CVRI (i.e., coronary vasoconstriction) was abolished by phentolamine at -5 mmHg (0.21 ± 0.06 vs. 0.83 ± 0.13), -10 mmHg (0.24 ± 0.03 vs. 1.68 ± 0.31), and -15 mmHg (0.27 ± 0.10 vs. 2.34 ± 0.43). These data indicate that alpha-adrenergic coronary vasoconstriction is present during low levels of LBNP. With alpha blockade, more coronary flow is needed to maintain cardiac function. Our data suggest that alpha-adrenergic tone enhances coronary flow efficiency, presumably by redistributing flow from the epicardium to the endocardium.
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Affiliation(s)
- Zhaohui Gao
- Penn State Hershey Heart and Vascular Institute, The Pennsylvania State University College of Medicine, The Milton S. Hershey Medical Center, Hershey, Pennsylvania
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Muller MD, Drew RC, Cui J, Blaha CA, Mast JL, Sinoway LI. Effect of oxidative stress on sympathetic and renal vascular responses to ischemic exercise. Physiol Rep 2013; 1. [PMID: 24098855 PMCID: PMC3787721 DOI: 10.1002/phy2.47] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Reactive oxygen species (ROS), produced acutely during skeletal muscle contraction, are known to stimulate group IV muscle afferents and accentuate the exercise pressor reflex (EPR) in rodents. The effect of ROS on the EPR in humans is unknown. We conducted a series of studies using ischemic fatiguing rhythmic handgrip to acutely increase ROS within skeletal muscle, ascorbic acid infusion to scavenge free radicals, and hyperoxia inhalation to further increase ROS production. We hypothesized that ascorbic acid would attenuate the EPR and that hyperoxia would accentuate the EPR. Ten young healthy subjects participated in two or three experimental trials on separate days. Beat-by-beat measurements of heart rate (HR), mean arterial pressure (MAP), muscle sympathetic nerve activity (MSNA), and renal vascular resistance index (RVRI) were measured and compared between treatments (saline and ascorbic acid; room air and hyperoxia). At fatigue, the reflex increases in MAP (31 ± 3 versus 29 ± 2 mmHg), HR (19 ± 3 versus 20 ± 3 bpm), MSNA burst rate (21 ± 4 versus 23 ± 4 burst/min), and RVRI (39 ± 12 versus 44 ± 13%) were not different between saline and ascorbic acid. Relative to room air, hyperoxia did not augment the reflex increases in MAP, HR, MSNA, or RVRI in response to exercise. Muscle metaboreflex activation and time/volume control experiments similarly showed no treatment effects. While contrary to our initial hypotheses, these findings suggest that ROS do not play a significant role in the normal reflex adjustments to ischemic exercise in young healthy humans.
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Affiliation(s)
- Matthew D Muller
- Pennsylvania State University College of Medicine, Penn State Hershey Heart and Vascular Institute, 500 University Drive, Hershey, PA 17033
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Shuvy M, Atar D, Gabriel Steg P, Halvorsen S, Jolly S, Yusuf S, Lotan C. Oxygen therapy in acute coronary syndrome: are the benefits worth the risk? Eur Heart J 2013; 34:1630-5. [PMID: 23554440 DOI: 10.1093/eurheartj/eht110] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Oxygen supplementation is a standard treatment for all patients who present with acute coronary syndrome, regardless of oxygen saturation levels. Most of the data regarding the function of oxygen in myocardial infarction is based on a limited number of basic and clinical studies. We performed a systematic literature review that explores the basic and clinical data on the function of oxygen in ischaemic heart disease and myocardial infarction. This review discusses many aspects of oxygen treatment: (i) basic studies on the effects of oxygen in ischaemia and the potential cardiovascular effects of oxygen metabolites; (ii) clinical trials that have assessed the value of inhaled oxygen, supersaturated oxygen, and intracoronary injection of hyperoxaemic solutions in myocardial infarction; and (iii) the haemodynamic effects of oxygen in various clinical scenarios and its direct effects on the coronary vasculature. Our findings suggest that there are conflicting data on the effects of oxygen treatment. Further, the potential harmful effects of oxygen must be considered, particularly in myocardial infarction. These findings question the current guidelines and recommendations and emphasize the need for large clinical trials.
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Affiliation(s)
- Mony Shuvy
- Heart Institute, Hadassah Hebrew University Medical Center, PO Box 12000, Jerusalem, Israel.
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Gao Z, Novick M, Muller MD, Williams RJ, Spilk S, Leuenberger UA, Sinoway LI. Exercise and diet-induced weight loss attenuates oxidative stress related-coronary vasoconstriction in obese adolescents. Eur J Appl Physiol 2013; 113:519-28. [PMID: 22814577 PMCID: PMC3613987 DOI: 10.1007/s00421-012-2459-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2012] [Accepted: 07/05/2012] [Indexed: 01/20/2023]
Abstract
Obesity is a disease of oxidative stress (OS). Acute hyperoxia (breathing 100 % O(2)) can evoke coronary vasoconstriction by the oxidative quenching of nitric oxide (NO). To examine if weight loss would alter the hyperoxia-related coronary constriction seen in obese adolescents, we measured the coronary blood flow velocity (CBV) response to hyperoxia using transthoracic Doppler echocardiography before and after a 4-week diet and exercise regimen in 6 obese male adolescents (age 13-17 years, BMI 36.5 ± 2.3 kg/m(2)). Six controls of similar age and BMI were also studied. The intervention group lost 9 ± 1 % body weight, which was associated with a reduced resting heart rate (HR), reduced diastolic blood pressure (BP), and reduced RPP (all P < 0.05). Before weight loss, hyperoxia reduced CBV by 33 ± 3 %. After weight loss, CBV only fell by 15 ± 3 % (P < 0.05). In the control group, CBV responses to hyperoxia were unchanged during the two trials. Thus weight loss: (1) reduces HR, BP, and RPP; and (2) attenuates the OS-related coronary constrictor response seen in obese adolescents. We postulate that: (1) the high RPP before weight loss led to higher myocardial O(2) consumption, higher coronary flow and greater NO production, and in turn a large constrictor response to hyperoxia; and (2) weight loss decreased myocardial oxygen demand and NO levels. Under these circumstances, hyperoxia-induced vasoconstriction was attenuated.
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Affiliation(s)
- Zhaohui Gao
- Penn State Hershey Heart & Vascular Institute, The Pennsylvania State University College of Medicine, The Milton S. Hershey Medical Center, Hershey, Pennsylvania 17033
| | - Marsha Novick
- Penn State Children’s Hospital, The Pennsylvania State University College of Medicine, The Milton S. Hershey Medical Center, Hershey, Pennsylvania 17033
| | - Matthew D. Muller
- Penn State Hershey Heart & Vascular Institute, The Pennsylvania State University College of Medicine, The Milton S. Hershey Medical Center, Hershey, Pennsylvania 17033
| | - Ronald J. Williams
- Penn State Children’s Hospital, The Pennsylvania State University College of Medicine, The Milton S. Hershey Medical Center, Hershey, Pennsylvania 17033
| | - Samson Spilk
- Penn State Hershey Heart & Vascular Institute, The Pennsylvania State University College of Medicine, The Milton S. Hershey Medical Center, Hershey, Pennsylvania 17033
| | - Urs A. Leuenberger
- Penn State Hershey Heart & Vascular Institute, The Pennsylvania State University College of Medicine, The Milton S. Hershey Medical Center, Hershey, Pennsylvania 17033
| | - Lawrence I. Sinoway
- Penn State Hershey Heart & Vascular Institute, The Pennsylvania State University College of Medicine, The Milton S. Hershey Medical Center, Hershey, Pennsylvania 17033
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Qi Z, Liu W, Luo Y, Ji X, Liu KJ. Normobaric hyperoxia-based neuroprotective therapies in ischemic stroke. Med Gas Res 2013; 3:2. [PMID: 23298701 PMCID: PMC3552719 DOI: 10.1186/2045-9912-3-2] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2012] [Accepted: 01/07/2013] [Indexed: 01/11/2023] Open
Abstract
Stroke is a leading cause of death and disability due to disturbance of blood supply to the brain. As brain is highly sensitive to hypoxia, insufficient oxygen supply is a critical event contributing to ischemic brain injury. Normobaric hyperoxia (NBO) that aims to enhance oxygen delivery to hypoxic tissues has long been considered as a logical neuroprotective therapy for ischemic stroke. To date, many possible mechanisms have been reported to elucidate NBO’s neuroprotection, such as improving tissue oxygenation, increasing cerebral blood flow, reducing oxidative stress and protecting the blood brain barrier. As ischemic stroke triggers a battery of damaging events, combining NBO with other agents or treatments that target multiple mechanisms of injury may achieve better outcome than individual treatment alone. More importantly, time loss is brain loss in acute cerebral ischemia. NBO can be a rapid therapy to attenuate or slow down the evolution of ischemic tissues towards necrosis and therefore “buy time” for reperfusion therapies. This article summarizes the current literatures on NBO as a simple, widely accessible, and potentially cost-effective therapeutic strategy for treatment of acute ischemic stroke.
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Affiliation(s)
- Zhifeng Qi
- Cerebrovascular Diseases Research Institute, Xuanwu Hospital of Capital Medical University, No,45 Changchun Street, Beijing, 100053, China.
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Souto EB, Severino P, Basso R, Santana MHA. Encapsulation of antioxidants in gastrointestinal-resistant nanoparticulate carriers. Methods Mol Biol 2013; 1028:37-46. [PMID: 23740112 DOI: 10.1007/978-1-62703-475-3_3] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Reactive oxygen species (ROS) are known to cause several human pathologies. For this reason, antioxidants have gained utmost importance because of their potential as prophylactic and therapeutic agents in many diseases. Examples of their application include their use in diabetic patients, as aging drugs, in cancer diseases, Parkinson's, Alzheimer's, autoimmune disorders, and also in inflammation. Antioxidants have limited absorption profiles, therefore low bioavailability and low concentrations at the target site. Efforts have been done towards loading antioxidant molecules in advanced nanoparticulate carriers, e.g., liposomes, polymeric nanoparticles, solid lipid nanoparticles, self-emulsifying drug delivery system. Examples of -successful achievements include the encapsulation of drugs and other active ingredients, e.g., coenzyme Q10, vitamin E and vitamin A, resveratrol and polyphenols, curcumin, lycopene, silymarin, and superoxide dismutase. This review focuses on the comprehensive analysis of using nanoparticulate carriers for loading these molecules for oral administration.
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Affiliation(s)
- Eliana B Souto
- Faculty of Health Sciences, Centre of Genetics and Biotechnology, Institute of Biotechnology and Bioengineering, Fernando Pessoa University, Porto, Portugal
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Modun D, Krnic M, Vukovic J, Kokic V, Kukoc-Modun L, Tsikas D, Dujic Z. Plasma nitrite concentration decreases after hyperoxia-induced oxidative stress in healthy humans. Clin Physiol Funct Imaging 2012; 32:404-8. [PMID: 22856349 DOI: 10.1111/j.1475-097x.2012.01133.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2011] [Accepted: 03/15/2012] [Indexed: 11/28/2022]
Abstract
The aim of this study was to measure plasma nitrite, the biochemical marker of endothelial nitric oxide ((•)NO) synthesis, before and after hyperoxia, in order to test the hypothesis that hyperoxia-induced vasoconstriction is a consequence of reduced bioavailability of (•)NO caused by elevated oxidative stress. Ten healthy men breathed 100% normobaric O(2) for 30 min between 15th and 45th min of the 1-h study protocol. Plasma nitrite and malondialdehyde (MDA), arterial stiffness (indicated by augmentation index, AIx) and arterial oxygen (P(tc)O(2)) pressure were measured at 1st, 15th, 45th and 60th minute of the study. Breathing of normobaric 100% oxygen during 30 min caused an increase in P(tc)O(2) (from 75 ± 2 to 412 ± 25 mm Hg), AIx (from -63 ± 4 to -51 ± 3%) and MDA (from 152 ± 13 to 218 ± 15 nm) values and a decrease in plasma nitrite (from 918 ± 58 to 773 ± 55 nm). During the 15-min recovery phase, plasma nitrite, AIx and MDA values remained altered. This study suggests that the underlying mechanism of hyperoxia-induced vasoconstriction may involve reduced (•)NO bioavailability caused by elevated and sustained oxidative stress.
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Affiliation(s)
- Darko Modun
- Department of Pharmacology, University of Split School of Medicine, Split, Croatia.
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Muller MD, Gao Z, Mast JL, Blaha CA, Drew RC, Leuenberger UA, Sinoway LI. Aging attenuates the coronary blood flow response to cold air breathing and isometric handgrip in healthy humans. Am J Physiol Heart Circ Physiol 2012; 302:H1737-46. [PMID: 22345567 DOI: 10.1152/ajpheart.01195.2011] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The purpose of this echocardiography study was to measure peak coronary blood flow velocity (CBV(peak)) and left ventricular function (via tissue Doppler imaging) during separate and combined bouts of cold air inhalation (-14 ± 3°C) and isometric handgrip (30% maximum voluntary contraction). Thirteen young adults and thirteen older adults volunteered to participate in this study and underwent echocardiographic examination in the left lateral position. Cold air inhalation was 5 min in duration, and isometric handgrip (grip protocol) was 2 min in duration; a combined stimulus (cold + grip protocol) and a cold pressor test (hand in 1°C water) were also performed. Heart rate, blood pressure, O(2) saturation, and inspired air temperature were monitored on a beat-by-beat basis. The rate-pressure product (RPP) was used as an index of myocardial O(2) demand, and CBV(peak) was used as an index of myocardial O(2) supply. The RPP response to the grip protocol was significantly blunted in older subjects (Δ1,964 ± 396 beats·min(-1)·mmHg) compared with young subjects (Δ3,898 ± 452 beats·min(-1)·mmHg), and the change in CBV(peak) was also blunted (Δ6.3 ± 1.2 vs. 11.2 ± 2.0 cm/s). Paired t-tests showed that older subjects had a greater change in the RPP during the cold + grip protocol [Δ2,697 ± 391 beats·min(-1)·mmHg compared with the grip protocol alone (Δ2,115 ± 375 beats·min(-1)·mmHg)]. An accentuated RPP response to the cold + grip protocol (compared with the grip protocol alone) without a concomitant increase in CBV(peak) may suggest a dissociation between the O(2) supply and demand in the coronary circulation. In conclusion, older adults have blunted coronary blood flow responses to isometric exercise.
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Affiliation(s)
- Matthew D Muller
- Penn State Heart and Vascular Institute, Pennsylvania State University College of Medicine, Milton S. Hershey Medical Center, Hershey, Pennsylvania, USA
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