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Rathi V, Sagi SSK, Yadav AK, Kumar M, Varshney R. Quercetin prophylaxis protects the kidneys by modulating the renin-angiotensin-aldosterone axis under acute hypobaric hypoxic stress. Sci Rep 2024; 14:7617. [PMID: 38556603 PMCID: PMC10982295 DOI: 10.1038/s41598-024-58134-3] [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: 07/18/2023] [Accepted: 03/26/2024] [Indexed: 04/02/2024] Open
Abstract
The study presented here aims at assessing the effects of hypobaric hypoxia on RAAS pathway and its components along with mitigation of anomalies with quercetin prophylaxis. One hour prior to hypobaric hypoxia exposure, male SD rats were orally supplemented with quercetin (50 mg/kg BW) and acetazolamide (50 mg/kg BW) and exposed them to 25,000 ft. (7,620 m) in a simulated environmental chamber for 12 h at 25 ± 2 °C. Different biochemical parameters like renin activity, aldosterone, angiotensin I, ACE 2 were determined in plasma. As a conventional response to low oxygen conditions, oxidative stress parameters (ROS and MDA) were elevated along with suppressed antioxidant system (GPx and catalase) in plasma of rats. Quercetin prophylaxis significantly down regulated the hypoxia induced oxidative stress by reducing plasma ROS & MDA levels with efficient enhancement of antioxidants (GPx and Catalase). Further, hypoxia mediated regulation of renin and ACE 2 proves the outstanding efficacy of quercetin in repudiating altercations in RAAS cascade due to hypobaric hypoxia. Furthermore, differential protein expression of HIF-1α, NFκB, IL-18 and endothelin-1 analyzed by western blotting approves the biochemical outcomes and showed that quercetin significantly aids in the reduction of inflammation under hypoxia. Studies conducted with Surface Plasmon Resonance demonstrated a binding among quercetin and ACE 2 that indicates that this flavonoid might regulate RAAS pathway via ACE 2. Henceforth, the study promotes the prophylaxis of quercetin for the better adaptability under hypobaric hypoxic conditions via modulating the RAAS pathway.
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Affiliation(s)
- Vaishnavi Rathi
- Defence Institute of Physiology and Allied Sciences, DRDO, Lucknow Road, Timarpur, New Delhi, 110054, India
| | - Sarada S K Sagi
- Defence Institute of Physiology and Allied Sciences, DRDO, Lucknow Road, Timarpur, New Delhi, 110054, India.
| | - Amit Kumar Yadav
- Department of Biophysics, All India Institute of Medical Science, Delhi, India
| | - Manoj Kumar
- Department of Biophysics, All India Institute of Medical Science, Delhi, India
| | - Rajeev Varshney
- Defence Institute of Physiology and Allied Sciences, DRDO, Lucknow Road, Timarpur, New Delhi, 110054, India
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Müller J, Appenzeller P, Lichtblau M, Saxer S, Berlier C, Schneider SR, Furian M, Schwarz EI, Swenson ER, Bloch KE, Ulrich S. Effects of 5-Week Oral Acetazolamide on Incremental Cycling Exercise in Pulmonary Arterial and Chronic Thromboembolic Pulmonary Hypertension: A Randomized Placebo-Controlled, Double-Blinded, Crossover Trial. Respiration 2024; 103:124-133. [PMID: 38382479 DOI: 10.1159/000536399] [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: 11/16/2023] [Accepted: 01/18/2024] [Indexed: 02/23/2024] Open
Abstract
INTRODUCTION Acetazolamide (AZA) improves nocturnal and daytime blood oxygenation in patients with pulmonary vascular disease (PVD), defined as pulmonary arterial and distal chronic thromboembolic pulmonary hypertension (CTEPH), and may improve exercise performance. METHODS We investigated the effect of 5 weeks of AZA (250 mg bid) versus placebo on maximal load during incremental cycling ramp exercise in patients with PVD studied in a randomized controlled, double-blind, crossover design, separated by > 2 weeks of washout. RESULTS Twenty-five patients (12 pulmonary arterial hypertension, 13 CTEPH, 40% women, age 62 ± 15 years) completed the trial according to the protocol. Maximum load was similar after 5 weeks of AZA versus placebo (113 ± 9 vs. 117 ± 9 watts [W]), mean difference -4 W (95% CI: -9 to 1, p = 0.138). With AZA, maximum (max)-exercise partial pressure of O2 (PaO2) was significantly higher by 1.1 kPa (95% CI: 0.5-1.8, p = 0.003), while arterial pH and partial pressure of CO2 were significantly lower. Gas exchange threshold was reached at a higher load with AZA (108 ± 8 W vs. 97 ± 8 W) and was therefore delayed by 11 W (95% CI: 3-19, p = 0.013), while the ventilatory equivalent for O2 and CO2 were significantly higher at both the max-exercise and gas exchange threshold with AZA versus placebo. CONCLUSION AZA for 5 weeks did not significantly change maximum exercise capacity in patients with PVD despite a significant increase in PaO2. The beneficial effects of increased blood oxygenation may have been diminished by increased ventilation due to AZA-induced metabolic acidosis and increased dyspnea.
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Affiliation(s)
- Julian Müller
- Clinic of Pulmonology, University Hospital Zurich, Zurich, Switzerland,
- Faculty of Medicine, University of Zurich, Zurich, Switzerland,
| | - Paula Appenzeller
- Clinic of Pulmonology, University Hospital Zurich, Zurich, Switzerland
- Faculty of Medicine, University of Zurich, Zurich, Switzerland
| | - Mona Lichtblau
- Clinic of Pulmonology, University Hospital Zurich, Zurich, Switzerland
- Faculty of Medicine, University of Zurich, Zurich, Switzerland
| | - Stéphanie Saxer
- Clinic of Pulmonology, University Hospital Zurich, Zurich, Switzerland
- Faculty of Medicine, University of Zurich, Zurich, Switzerland
| | - Charlotte Berlier
- Clinic of Pulmonology, University Hospital Zurich, Zurich, Switzerland
- Faculty of Medicine, University of Zurich, Zurich, Switzerland
| | - Simon R Schneider
- Clinic of Pulmonology, University Hospital Zurich, Zurich, Switzerland
- Faculty of Medicine, University of Zurich, Zurich, Switzerland
| | - Michael Furian
- Clinic of Pulmonology, University Hospital Zurich, Zurich, Switzerland
- Faculty of Medicine, University of Zurich, Zurich, Switzerland
| | - Esther I Schwarz
- Clinic of Pulmonology, University Hospital Zurich, Zurich, Switzerland
- Faculty of Medicine, University of Zurich, Zurich, Switzerland
| | - Erik R Swenson
- Division of Pulmonary, Critical Care and Sleep Medicine, University of Washington, Seattle, Washington, USA
| | - Konrad E Bloch
- Clinic of Pulmonology, University Hospital Zurich, Zurich, Switzerland
- Faculty of Medicine, University of Zurich, Zurich, Switzerland
| | - Silvia Ulrich
- Clinic of Pulmonology, University Hospital Zurich, Zurich, Switzerland
- Faculty of Medicine, University of Zurich, Zurich, Switzerland
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Christou H, Khalil RA. Mechanisms of pulmonary vascular dysfunction in pulmonary hypertension and implications for novel therapies. Am J Physiol Heart Circ Physiol 2022; 322:H702-H724. [PMID: 35213243 PMCID: PMC8977136 DOI: 10.1152/ajpheart.00021.2022] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Revised: 02/22/2022] [Accepted: 02/22/2022] [Indexed: 12/21/2022]
Abstract
Pulmonary hypertension (PH) is a serious disease characterized by various degrees of pulmonary vasoconstriction and progressive fibroproliferative remodeling and inflammation of the pulmonary arterioles that lead to increased pulmonary vascular resistance, right ventricular hypertrophy, and failure. Pulmonary vascular tone is regulated by a balance between vasoconstrictor and vasodilator mediators, and a shift in this balance to vasoconstriction is an important component of PH pathology, Therefore, the mainstay of current pharmacological therapies centers on pulmonary vasodilation methodologies that either enhance vasodilator mechanisms such as the NO-cGMP and prostacyclin-cAMP pathways and/or inhibit vasoconstrictor mechanisms such as the endothelin-1, cytosolic Ca2+, and Rho-kinase pathways. However, in addition to the increased vascular tone, many patients have a "fixed" component in their disease that involves altered biology of various cells in the pulmonary vascular wall, excessive pulmonary artery remodeling, and perivascular fibrosis and inflammation. Pulmonary arterial smooth muscle cell (PASMC) phenotypic switch from a contractile to a synthetic and proliferative phenotype is an important factor in pulmonary artery remodeling. Although current vasodilator therapies also have some antiproliferative effects on PASMCs, they are not universally successful in halting PH progression and increasing survival. Mild acidification and other novel approaches that aim to reverse the resident pulmonary vascular pathology and structural remodeling and restore a contractile PASMC phenotype could ameliorate vascular remodeling and enhance the responsiveness of PH to vasodilator therapies.
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Affiliation(s)
- Helen Christou
- Department of Pediatric Newborn Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Raouf A Khalil
- Division of Vascular and Endovascular Surgery, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts
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Duknic M, Lichtblau M, Saxer S, Berlier C, Schneider SR, Schwarz EI, Carta AF, Furian M, Bloch KE, Ulrich S. Comparison of Repetitive Cardiac Output Measurements at Rest and End-Exercise by Direct Fick Using Pulse Oximetry vs. Blood Gases in Patients With Pulmonary Hypertension. Front Med (Lausanne) 2021; 8:776956. [PMID: 34888330 PMCID: PMC8649780 DOI: 10.3389/fmed.2021.776956] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Accepted: 10/25/2021] [Indexed: 11/22/2022] Open
Abstract
Background: Exact and simultaneous measurements of mean pulmonary artery pressure (mPAP) and cardiac output (CO) are crucial to calculate pulmonary vascular resistance (PVR), which is essential to define pulmonary hypertension (PH). Simultaneous measurements of mPAP and CO are not feasible using the direct Fick (DF) method, due to the necessity to sample blood from the catheter-tip. We evaluated a modified DF method, which allows simultaneous measurement of mPAP and CO without needing repetitive blood samples. Methods: Twenty-four patients with pulmonary arterial or chronic thromboembolic PH had repetitive measurements of CO at rest and end-exercise during three phases of a crossover trial. CO was assessed by the original DF method using oxygen uptake, measured by a metabolic unit, and arterial and mixed venous oxygen saturations from co-oximetry of respective blood gases served as reference. These CO measurements were then compared with a modified DF method using pulse oximetry at the catheter- and fingertip. Results: The bias among CO measurements by the two DF methods at rest was −0.26 L/min with limits of agreement of ±1.66 L/min. The percentage error was 28.6%. At the end-exercise, the bias between methods was 0.29 L/min with limits of agreement of ±1.54 L/min and percentage error of 16.1%. Conclusion: Direct Fick using a catheter- and fingertip pulse oximetry (DFp) is a practicable and reliable method for assessing CO in patients with PH. This method has the advantage of allowing simultaneous measurement of PAP and CO, and frequent repetitive measurements are needed during exercise. Clinical Trial Registration:https://clinicaltrials.gov/ct2/show/NCT02755259, identifier: NCT02755259.
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Affiliation(s)
- Milos Duknic
- Department of Pulmonology, University Hospital Zürich, Zurich, Switzerland.,University of Zurich, Zurich, Switzerland
| | - Mona Lichtblau
- Department of Pulmonology, University Hospital Zürich, Zurich, Switzerland.,University of Zurich, Zurich, Switzerland
| | - Stéphanie Saxer
- Department of Pulmonology, University Hospital Zürich, Zurich, Switzerland.,University of Zurich, Zurich, Switzerland
| | - Charlotte Berlier
- Department of Pulmonology, University Hospital Zürich, Zurich, Switzerland.,University of Zurich, Zurich, Switzerland
| | - Simon R Schneider
- Department of Pulmonology, University Hospital Zürich, Zurich, Switzerland.,University of Zurich, Zurich, Switzerland
| | - Esther I Schwarz
- Department of Pulmonology, University Hospital Zürich, Zurich, Switzerland.,University of Zurich, Zurich, Switzerland
| | - Arcangelo F Carta
- Department of Pulmonology, University Hospital Zürich, Zurich, Switzerland.,University of Zurich, Zurich, Switzerland
| | - Michael Furian
- Department of Pulmonology, University Hospital Zürich, Zurich, Switzerland.,University of Zurich, Zurich, Switzerland
| | - Konrad E Bloch
- Department of Pulmonology, University Hospital Zürich, Zurich, Switzerland.,University of Zurich, Zurich, Switzerland
| | - Silvia Ulrich
- Department of Pulmonology, University Hospital Zürich, Zurich, Switzerland.,University of Zurich, Zurich, Switzerland
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