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García-Llorca A, Carta F, Supuran CT, Eysteinsson T. Carbonic anhydrase, its inhibitors and vascular function. Front Mol Biosci 2024; 11:1338528. [PMID: 38348465 PMCID: PMC10859760 DOI: 10.3389/fmolb.2024.1338528] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2023] [Accepted: 01/03/2024] [Indexed: 02/15/2024] Open
Abstract
It has been known for some time that Carbonic Anhydrase (CA, EC 4.2.1.1) plays a complex role in vascular function, and in the regulation of vascular tone. Clinically employed CA inhibitors (CAIs) are used primarily to lower intraocular pressure in glaucoma, and also to affect retinal blood flow and oxygen saturation. CAIs have been shown to dilate vessels and increase blood flow in both the cerebral and ocular vasculature. Similar effects of CAIs on vascular function have been observed in the liver, brain and kidney, while vessels in abdominal muscle and the stomach are unaffected. Most of the studies on the vascular effects of CAIs have been focused on the cerebral and ocular vasculatures, and in particular the retinal vasculature, where vasodilation of its vessels, after intravenous infusion of sulfonamide-based CAIs can be easily observed and measured from the fundus of the eye. The mechanism by which CAIs exert their effects on the vasculature is still unclear, but the classic sulfonamide-based inhibitors have been found to directly dilate isolated vessel segments when applied to the extracellular fluid. Modification of the structure of CAI compounds affects their efficacy and potency as vasodilators. CAIs of the coumarin type, which generally are less effective in inhibiting the catalytically dominant isoform hCA II and unable to accept NO, have comparable vasodilatory effects as the primary sulfonamides on pre-contracted retinal arteriolar vessel segments, providing insights into which CA isoforms are involved. Alterations of the lipophilicity of CAI compounds affect their potency as vasodilators, and CAIs that are membrane impermeant do not act as vasodilators of isolated vessel segments. Experiments with CAIs, that shed light on the role of CA in the regulation of vascular tone of vessels, will be discussed in this review. The role of CA in vascular function will be discussed, with specific emphasis on findings with the effects of CA inhibitors (CAI).
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Affiliation(s)
- Andrea García-Llorca
- Department of Physiology, Faculty of Medicine, University of Iceland, Reykjavik, Iceland
| | - Fabrizio Carta
- NEUROFARBA Department, Section of Pharmaceutical and Nutraceutical Sciences, University of Florence, Florence, Italy
| | - Claudiu T. Supuran
- NEUROFARBA Department, Section of Pharmaceutical and Nutraceutical Sciences, University of Florence, Florence, Italy
| | - Thor Eysteinsson
- Department of Physiology, Faculty of Medicine, University of Iceland, Reykjavik, Iceland
- Department of Ophthalmology, Faculty of Medicine, University of Iceland, Reykjavik, Iceland
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Doherty CJ, Chang JC, Thompson BP, Swenson ER, Foster GE, Dominelli PB. The Impact of Acetazolamide and Methazolamide on Exercise Performance in Normoxia and Hypoxia. High Alt Med Biol 2023; 24:7-18. [PMID: 36802203 DOI: 10.1089/ham.2022.0134] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/23/2023] Open
Abstract
Doherty, Connor J., Jou-Chung Chang, Benjamin P. Thompson, Erik R. Swenson, Glen E. Foster, and Paolo B. Dominelli. The impact of acetazolamide and methazolamide on exercise performance in normoxia and hypoxia. High Alt Med Biol. 24:7-18, 2023.-Carbonic anhydrase (CA) inhibitors are commonly prescribed for acute mountain sickness (AMS). In this review, we sought to examine how two CA inhibitors, acetazolamide (AZ) and methazolamide (MZ), affect exercise performance in normoxia and hypoxia. First, we briefly describe the role of CA inhibition in facilitating the increase in ventilation and arterial oxygenation in preventing and treating AMS. Next, we detail how AZ affects exercise performance in normoxia and hypoxia and this is followed by a discussion on MZ. We emphasize that the overarching focus of the review is how the two drugs potentially affect exercise performance, rather than their ability to prevent/treat AMS per se, their interrelationship will be discussed. Overall, we suggest that AZ hinders exercise performance in normoxia, but may be beneficial in hypoxia. Based upon head-to-head studies of AZ and MZ in humans on diaphragmatic and locomotor strength in normoxia, MZ may be a better CA inhibitor when exercise performance is crucial at high altitude.
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Affiliation(s)
- Connor J Doherty
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada
| | - Jou-Chung Chang
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada
| | - Benjamin P Thompson
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada
| | - Erik R Swenson
- Division of Pulmonary, Critical Care and Sleep Medicine, University of Washington, Washington, USA
- Medical Service, VA Puget Sound Health Care System, Seattle, Washington, USA
| | - Glen E Foster
- School of Health and Exercise Sciences, University of British Columbia, Kelowna, British Columbia, Canada
| | - Paolo B Dominelli
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada
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Bian SZ, Zhang C, Rao RS, Ding XH, Huang L. Systemic Blood Predictors of Elevated Pulmonary Artery Pressure Assessed by Non-invasive Echocardiography After Acute Exposure to High Altitude: A Prospective Cohort Study. Front Cardiovasc Med 2022; 9:866093. [PMID: 35757324 PMCID: PMC9226344 DOI: 10.3389/fcvm.2022.866093] [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] [Received: 01/30/2022] [Accepted: 05/06/2022] [Indexed: 11/14/2022] Open
Abstract
Aim Elevated pulmonary artery pressure (ePAP) in response to high-altitude hypoxia is a critical physiopathological factor in the hypoxic adaptation that may lead to high-altitude pulmonary edema in the acute phase or high-altitude pulmonary hypertension in the long term. However, the sea-level predictors of risk factors for altitude-induced ePAP have not been examined. Thus, we aimed to identify the baseline systemic blood predictors of ePAP after acute high-altitude exposure. Materials and Methods A total of 154 participants were transported to a high altitude 3,700 m from sea level within 2 h. Echocardiography examinations were performed to assess the mean pulmonary artery pressure (mPAP) and hemodynamics at both altitudes. All the individuals underwent blood tests to determine the concentrations of vascular regulatory factors. Univariate and adjusted logistic regression analyses were performed to identify the independent predictors of ePAP and factors related to ePAP. Results The mPAP increased significantly from sea level to high altitude (19.79 ± 6.53–27.16 ± 7.16 mmHg, p < 0.05). Increased levels of endothelin (ET-1), Ang (1–7), Ang II, and bradykinin were found after high-altitude exposure, while the levels of nitric oxide (NO), prostaglandin E2 (PEG2), and serotonin decreased sharply (all p-values < 0.05). At high altitude, 52.6% of the subjects exhibited ePAP, and the mPAP was closely correlated with the baseline Ang II level (r = 0.170, p = 0.036) and follow-up levels of NO (r = −0.209, p = 0.009), Ang II (r = 0.246, p = 0.002), and Ang (1–7) (r = −0.222, p = 0.006) and the left atrial inner diameter (LAD, r = 0.270, p < 0.001). Both the baseline and follow-up NO and Ang II levels were significantly different between the ePAP and non-ePAP groups. Finally, we identified the baseline Ang II and NO concentrations as two independent predictors of ePAP (p < 0.05). We also found that two vascular regulatory factors with inverse roles, namely, Ang (1–7) and Ang II, at high altitudes were independently associated with ePAP. Additionally, ET-1, NO, PEG2, and LAD were associated with ePAP. Conclusion The baseline concentrations of Ang II and NO at sea level are two independent predictors of ePAP after acute high-altitude exposure. Furthermore, Ang (1-7) and Ang II combined with ET-1, NO, PEG2, and LAD at high altitudes may contribute to the development of ePAP.
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Affiliation(s)
- Shi-Zhu Bian
- Department of Cardiology, Xinqiao Hospital, Institute of Cardiovascular Diseases, Army Medical University (Third Military Medical University), Chongqing, China
| | - Chen Zhang
- Department of Cardiology, Xinqiao Hospital, Institute of Cardiovascular Diseases, Army Medical University (Third Military Medical University), Chongqing, China
| | - Rong-Sheng Rao
- Department of Ultrasonography, Xinqiao Hospital, Army Medical University (Third Military Medical University), Chongqing, China
| | - Xiao-Han Ding
- Department of Health Care and Geriatrics, The 940th Hospital of Joint Logistics Support of Chinese People’s Liberation Army (PLA), Lanzhou, China
| | - Lan Huang
- Department of Cardiology, Xinqiao Hospital, Institute of Cardiovascular Diseases, Army Medical University (Third Military Medical University), Chongqing, China
- *Correspondence: Lan Huang,
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Berger MM, Sareban M, Schiefer LM, Swenson KE, Treff F, Schäfer L, Schmidt P, Schimke MM, Paar M, Niebauer J, Cogo A, Kriemler S, Schwery S, Pickerodt PA, Mayer B, Bärtsch P, Swenson ER. Effects of acetazolamide on pulmonary artery pressure and prevention of high altitude pulmonary edema after rapid active ascent to 4,559 m. J Appl Physiol (1985) 2022; 132:1361-1369. [PMID: 35511718 DOI: 10.1152/japplphysiol.00806.2021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Acetazolamide prevents acute mountain sickness (AMS) by inhibition of carbonic anhydrase. Since it reduces acute hypoxic pulmonary vasoconstriction (HPV), it may also prevent high-altitude pulmonary edema (HAPE) by lowering pulmonary artery pressure. We tested this hypothesis in a randomized, placebo-controlled, double-blind study. Thirteen healthy, non-acclimatized lowlanders with a history of HAPE ascended (<22h) from 1,130 to 4,559m with one overnight stay at 3,611m. Medications started 48h before ascent (acetazolamide: n=7, 250mg 3x/d; placebo: n=6, 3x/d). HAPE was diagnosed by chest radiography, and pulmonary artery pressure by measurement of right ventricular to atrial pressure gradient (RVPG) by transthoracic echocardiography. AMS was evaluated with the Lake Louise Score (LLS) and AMS-C Score. Incidence of HAPE was 43% vs. 67% (acetazolamide vs. placebo, p=0.39). Ascent to altitude increased RVPG from 20±5 to 43±10mmHg (p<0.001) without a group difference (p=0.68). Arterial PO2 fell to 36±9mmHg (p<0.001) and was 8.5mmHg higher with acetazolamide at high altitude (p=0.025). At high altitude, the LLS and AMS-C score remained lower in those taking acetazolamide (both p<0.05). Although acetazolamide reduced HAPE incidence by 35%, this effect was not statistically significant, and considerably less than reductions of about 70-100% with prophylactic dexamethasone, tadalafil, and nifedipine performed with the same ascent profile at the same location. We could not demonstrate a reduction in RVPG compared to placebo treatment despite reductions in AMS severity and better arterial oxygenation. Limited by a small sample size, our data do not support recommending acetazolamide for prevention of HAPE in mountaineers ascending rapidly to over 4,500m.
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Affiliation(s)
- Marc Moritz Berger
- Department of Anesthesiology and Intensive Care Medicine, University Hospital Essen, University Duisburg-Essen, Essen, Germany
| | - Mahdi Sareban
- University Institute of Sports Medicine, Prevention and Rehabilitation, Paracelsus Medical University, Salzburg, Austria; Research Institute of Molecular Sports Medicine and Rehabilitation, Paracelsus Medical University, Salzburg, Austria
| | - Lisa Maria Schiefer
- Department of Anesthesiology, Critical Care and Pain Medicine, University Hospital Salzburg, Paracelsus Medical University, Salzburg, Austria
| | - Kai Erik Swenson
- Division of Pulmonary and Critical Care Medicine, Massachusetts General Hospital, Boston, MA, United States
| | - Franziska Treff
- Department of Anesthesiology, Critical Care and Pain Medicine, University Hospital Salzburg, Paracelsus Medical University, Salzburg, Austria
| | - Larissa Schäfer
- Department of Anesthesiology, Critical Care and Pain Medicine, University Hospital Salzburg, Paracelsus Medical University, Salzburg, Austria
| | - Peter Schmidt
- Department of Anesthesiology, Critical Care and Pain Medicine, University Hospital Salzburg, Paracelsus Medical University, Salzburg, Austria
| | - Magdalena M Schimke
- Department of Anesthesiology, Critical Care and Pain Medicine, University Hospital Salzburg, Paracelsus Medical University, Salzburg, Austria
| | - Michael Paar
- Department of Radiology, Paracelsus Medical University, Salzburg, Austria
| | - Josef Niebauer
- University Institute of Sports Medicine, Prevention and Rehabilitation, Paracelsus Medical University, Salzburg, Austria; Research Institute of Molecular Sports Medicine and Rehabilitation, Paracelsus Medical University, Salzburg, Austria
| | - Annalisa Cogo
- Biomedical Sport Studies Center, University of Ferrara, Ferrara, Italy
| | - Susi Kriemler
- Epidemiology, Biostatistics and Public Health Institute, University of Zürich, Zurich, Switzerland
| | | | - Philipp Andreas Pickerodt
- Department of Anesthesiology and Operative Intensive Care Medicine, Campus Charité Mitte and Virchow-Klinikum, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Benjamin Mayer
- Institute for Epidemiology and Medical Biometry, Ulm University, Ulm, Germany
| | - Peter Bärtsch
- Department of Internal Medicine, University of Heidelberg, Heidelberg, Germany
| | - Erik R Swenson
- Pulmonary, Critical Care and Sleep Medicine, VA Puget Sound Health Care System, University of Washington, Seattle, WA, United States
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Daniel D, Campos JC, Costa PC, Nunes B. Toxicity of two drugs towards the marine filter feeder Mytilus spp, using biochemical and shell integrity parameters. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2022; 293:118562. [PMID: 34813888 DOI: 10.1016/j.envpol.2021.118562] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 11/04/2021] [Accepted: 11/19/2021] [Indexed: 06/13/2023]
Abstract
The increasing presence of anthropogenic contaminants in the environment may constitute a challenge to non-target biota, considering that most contaminants can exert deleterious effects. Salicylic acid (SA) is a non-steroid anti-inflammatory drug (NSAID) which exerts its activity by inhibiting the enzyme cyclooxygenase (COX). Another class of drugs is that of the diuretics, in which acetazolamide (ACZ) is included. This pharmaceutical acts by inhibiting carbonic anhydrase (CA), a key enzyme in acid-base homeostasis, regulation of pH, being also responsible for the bio-availability of Ca2+ for shell biomineralization processes. In this work, we evaluated the chronic (28-day) ecotoxicological effects resulting from the exposures to SA and ACZ (alone, and in combination) on individuals of the marine mussel species Mytillus spp., using enzymatic (catalase (CAT), glutathione S-transferases (GSTs), COX and CA), non-enzymatic (lipid peroxidation, TBARS levels) and morphological and physiological (shell hardness, shell index and feeding behaviour) biomarkers. Exposure to ACZ and SA did not cause significant alterations in CAT and GSTs activities, and in TBARS levels. In terms of CA, this enzyme was inhibited by the highest concentration of ACZ in gills of exposed animals, but no effects occurred in the mantle tissue. The activity of COX was not altered after exposure to the single chemicals. However, animals exposed to the mixture of ACZ and SA evidenced a significant inhibition of COX activity. Morphological and physiological processes (namely, feeding, shell index, and shell hardness) were not affected by the here tested pharmaceutical drugs. Considering the general absence of adverse effects, further studies are needed to fully evaluate the effects of these pharmaceutical drugs on alternative biochemical and physiological pathways.
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Affiliation(s)
- David Daniel
- Departamento de Biologia, Universidade de Aveiro, Campus Universitário de Santiago, 3810-193, Aveiro, Portugal
| | - João C Campos
- UCIBIO, REQUIMTE, Laboratório de Tecnologia Farmacêutica, Departamento de Ciências Farmacêuticas, Faculdade de Farmácia, Universidade do Porto, Rua Jorge Viterbo Ferreira, 228, 4050-313, Porto, Portugal
| | - Paulo C Costa
- UCIBIO, REQUIMTE, Laboratório de Tecnologia Farmacêutica, Departamento de Ciências Farmacêuticas, Faculdade de Farmácia, Universidade do Porto, Rua Jorge Viterbo Ferreira, 228, 4050-313, Porto, Portugal
| | - Bruno Nunes
- Departamento de Biologia, Universidade de Aveiro, Campus Universitário de Santiago, 3810-193, Aveiro, Portugal; Centro de Estudos do Ambiente e do Mar (CESAM), Universidade de Aveiro, Campus Universitário de Santiago, 3810-193, Aveiro, Portugal.
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Shimoda LA, Suresh K, Undem C, Jiang H, Yun X, Sylvester JT, Swenson ER. Acetazolamide prevents hypoxia-induced reactive oxygen species generation and calcium release in pulmonary arterial smooth muscle. Pulm Circ 2021; 11:20458940211049948. [PMID: 34646499 PMCID: PMC8504243 DOI: 10.1177/20458940211049948] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Accepted: 09/13/2021] [Indexed: 11/16/2022] Open
Abstract
Upon sensing a reduction in local oxygen partial pressure, pulmonary vessels constrict, a phenomenon known as hypoxic pulmonary vasoconstriction. Excessive hypoxic pulmonary vasoconstriction can occur with ascent to high altitude and is a contributing factor to the development of high-altitude pulmonary edema. The carbonic anhydrase inhibitor, acetazolamide, attenuates hypoxic pulmonary vasoconstriction through stimulation of alveolar ventilation via modulation of acid-base homeostasis and by direct effects on pulmonary vascular smooth muscle. In pulmonary arterial smooth muscle cells (PASMCs), acetazolamide prevents hypoxia-induced increases in intracellular calcium concentration ([Ca2+]i), although the exact mechanism by which this occurs is unknown. In this study, we explored the effect of acetazolamide on various calcium-handling pathways in PASMCs. Using fluorescent microscopy, we tested whether acetazolamide directly inhibited store-operated calcium entry or calcium release from the sarcoplasmic reticulum, two well-documented sources of hypoxia-induced increases in [Ca2+]i in PASMCs. Acetazolamide had no effect on calcium entry stimulated by store-depletion, nor on calcium release from the sarcoplasmic reticulum induced by either phenylephrine to activate inositol triphosphate receptors or caffeine to activate ryanodine receptors. In contrast, acetazolamide completely prevented Ca2+-release from the sarcoplasmic reticulum induced by hypoxia (4% O2). Since these results suggest the acetazolamide interferes with a mechanism upstream of the inositol triphosphate and ryanodine receptors, we also determined whether acetazolamide might prevent hypoxia-induced changes in reactive oxygen species production. Using roGFP, a ratiometric reactive oxygen species-sensitive fluorescent probe, we found that hypoxia caused a significant increase in reactive oxygen species in PASMCs that was prevented by 100 μM acetazolamide. Together, these results suggest that acetazolamide prevents hypoxia-induced changes in [Ca2+]i by attenuating reactive oxygen species production and subsequent activation of Ca2+-release from sarcoplasmic reticulum stores.
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Affiliation(s)
- Larissa A Shimoda
- Division of Pulmonary and Critical Care Medicine, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - Karthik Suresh
- Division of Pulmonary and Critical Care Medicine, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - Clark Undem
- Division of Pulmonary and Critical Care Medicine, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - Haiyang Jiang
- Division of Pulmonary and Critical Care Medicine, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - Xin Yun
- Division of Pulmonary and Critical Care Medicine, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - J T Sylvester
- Division of Pulmonary and Critical Care Medicine, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - Erik R Swenson
- Division of Pulmonary and Critical Care Medicine, VA Puget Sound Health Care System and University of Washington School of Medicine, St. Louis, MO, USA
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iTRAQ-based quantitative proteomic analysis of the improved effects of total flavones of Dracocephalum Moldavica L. in chronic mountain sickness. Sci Rep 2021; 11:17526. [PMID: 34471201 PMCID: PMC8410788 DOI: 10.1038/s41598-021-97091-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2021] [Accepted: 08/19/2021] [Indexed: 01/14/2023] Open
Abstract
To use isobaric tags for relative and absolute quantification (iTRAQ) technology to study the pathogenesis of chronic mountain sickness (CMS), identify biomarkers for CMS, and investigate the effect of total flavones of Dracocephalum moldavica L. (TFDM) on a rat model of CMS. We simulated high altitude hypobaric hypoxia conditions and generated a rat model of CMS. Following the administration of TFDM, we measured the pulmonary artery pressure and serum levels of hemoglobin (Hb), the hematocrit (Hct), and observed the structure of the pulmonary artery in experimental rats. Furthermore, we applied iTRAQ-labeled quantitative proteomics technology to identify differentially expressed proteins (DEPs) in the serum, performed bioinformatics analysis, and verified the DEPs by immunohistochemistry. Analysis showed that the pulmonary artery pressure, serum levels of Hb, and the Hct, were significantly increased in a rat model of CMS (P < 0.05). Pathological analysis of lung tissue and pulmonary artery tissue showed that the alveolar compartment had obvious hyperplasia and the pulmonary artery degree of muscularization was enhanced. Both pulmonary artery pressure and tissue morphology were improved following the administration of TFDM. We identified 532 DEPs by quantitative proteomics; gene ontology (GO)and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis further revealed that metabolic pathways associated with coagulation and complement play crucial roles in the occurrence of CMS. Immunohistochemistry verified that several DEPs (α-1-acid glycoprotein, collagen, fibulin, haptoglobin, PLTP, and TAGLN2) are important biological markers for CMS. Our analyses demonstrated that TFDM can improve CMS and exert action by influencing the metabolic pathways associated with coagulation and complement. This process relieves pulmonary artery pressure and improves lung function. We also identified that α-1-acid glycoprotein, collagen, fibulin, haptoglobin, PLTP, and TAGLN2 may represent potential biomarkers for CMS.
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Lichtblau M, Berlier C, Saxer S, Carta AF, Mayer L, Groth A, Bader PR, Schneider SR, Furian M, Schwarz EI, Swenson ER, Bloch KE, Ulrich S. Acute Hemodynamic Effect of Acetazolamide in Patients With Pulmonary Hypertension Whilst Breathing Normoxic and Hypoxic Gas: A Randomized Cross-Over Trial. Front Med (Lausanne) 2021; 8:681473. [PMID: 34368187 PMCID: PMC8341560 DOI: 10.3389/fmed.2021.681473] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Accepted: 06/24/2021] [Indexed: 01/30/2023] Open
Abstract
Aims: To test the acute hemodynamic effect of acetazolamide in patients with pulmonary hypertension (PH) under ambient air and hypoxia. Methods: Patients with pulmonary arterial or chronic thromboembolic PH (PAH/CTEPH) undergoing right heart catheterization were included in this randomized, placebo-controlled, double-blinded, crossover trial. The main outcome, pulmonary vascular resistance (PVR), further hemodynamics, blood- and cerebral oxygenation were measured 1 h after intravenous administration of 500 mg acetazolamide or placebo-saline on ambient air (normoxia) and at the end of breathing hypoxic gas (FIO2 0.15, hypoxia) for 15 min. Results: 24 PH-patients, 71% men, mean ± SD age 59 ± 14 years, BMI 28 ± 5 kg/m2, PVR 4.7 ± 2.1 WU participated. Mean PVR after acetazolamide vs. placebo was 5.5 ± 3.0 vs. 5.3 ± 3.0 WU; mean difference (95% CI) 0.2 (−0.2–0.6, p = 0.341). Heart rate was higher after acetazolamide (79 ± 12 vs. 77 ± 11 bpm, p = 0.026), pH was lower (7.40 ± 0.02 vs. 7.42 ± 0.03, p = 0.002) but PaCO2 and PaO2 remained unchanged while cerebral tissue oxygenation increased (71 ± 6 vs. 69 ± 6%, p = 0.017). In acute hypoxia, acetazolamide decreased PVR by 0.4 WU (0.0–0.9, p = 0.046) while PaO2 and PaCO2 were not changed. No adverse effects occurred. Conclusions: In patients with PAH/CTEPH, i.v. acetazolamide did not change pulmonary hemodynamics compared to placebo after 1 hour in normoxia but it reduced PVR after subsequent acute exposure to hypoxia. Our findings in normoxia do not suggest a direct acute pulmonary vasodilator effect of acetazolamide. The reduction of PVR during hypoxia requires further corroboration. Whether acetazolamide improves PH when given over a prolonged period by stimulating ventilation, increasing oxygenation, and/or altering vascular inflammation and remodeling remains to be investigated.
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Affiliation(s)
- Mona Lichtblau
- Clinic of Pulmonology, University Hospital Zurich, Zurich, Switzerland
| | - Charlotte Berlier
- Clinic of Pulmonology, University Hospital Zurich, Zurich, Switzerland
| | - Stéphanie Saxer
- Clinic of Pulmonology, University Hospital Zurich, Zurich, Switzerland
| | - Arcangelo F Carta
- Clinic of Pulmonology, University Hospital Zurich, Zurich, Switzerland
| | - Laura Mayer
- Clinic of Pulmonology, University Hospital Zurich, Zurich, Switzerland
| | - Alexandra Groth
- Clinic of Pulmonology, University Hospital Zurich, Zurich, Switzerland
| | - Patrick R Bader
- Clinic of Pulmonology, University Hospital Zurich, Zurich, Switzerland
| | - Simon R Schneider
- Clinic of Pulmonology, University Hospital Zurich, Zurich, Switzerland
| | - Michael Furian
- Clinic of Pulmonology, University Hospital Zurich, Zurich, Switzerland
| | - Esther I Schwarz
- Clinic of Pulmonology, University Hospital Zurich, Zurich, Switzerland
| | - Erik R Swenson
- Division of Pulmonary, Critical Care and Sleep Medicine, VA Puget Sound Health Care System, University of Washington, Seattle, WA, United States
| | - Konrad E Bloch
- Clinic of Pulmonology, University Hospital Zurich, Zurich, Switzerland
| | - Silvia Ulrich
- Clinic of Pulmonology, University Hospital Zurich, Zurich, Switzerland
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Toussaint CM, Kenefick RW, Petrassi FA, Muza SR, Charkoudian N. Altitude, Acute Mountain Sickness, and Acetazolamide: Recommendations for Rapid Ascent. High Alt Med Biol 2020; 22:5-13. [PMID: 32975448 DOI: 10.1089/ham.2019.0123] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Toussaint, Claudia M., Robert W. Kenefick, Frank A. Petrassi, Stephen R. Muza, and Nisha Charkoudian. Altitude, acute mountain sickness, and acetazolamide: recommendations for rapid ascent. High Alt Med Biol. 22:5-13, 2021. Background: Sea level natives ascending rapidly to altitudes above 1,500 m often develop acute mountain sickness (AMS), including nausea, headaches, fatigue, and lightheadedness. Acetazolamide (AZ), a carbonic anhydrase inhibitor, is a commonly used medication for the prevention and treatment of AMS. However, there is continued debate about appropriate dosing, particularly when considering rapid and physically demanding ascents to elevations above 3,500 m by emergency medical and military personnel. Aims: Our goal in the present analysis was to evaluate and synthesize the current literature regarding the use of AZ to determine the most effective dosing for prophylaxis and treatment of AMS for rapid ascents to elevations >3,500 m. These circumstances are specifically relevant to military and emergency medical personnel who often need to ascend rapidly and perform physically demanding tasks upon arrival at altitude. Methods: We conducted a literature search from April 2018 to February 2020 using PubMed, Google Scholar, and Web of Science to identify randomized controlled trials that compared AZ with placebo or other treatment with the primary endpoint of AMS incidence and severity. We included only research articles/studies that focused on evaluation of AZ use during rapid ascent. Results: Four doses of AZ (125, 250, 500, and 750 mg daily) were identified as efficacious in decreasing the incidence and/or severity of AMS during rapid ascents, with evidence of enhanced effectiveness with higher doses. Conclusions: For military, emergency medical, or other activities involving rapid ascent to altitudes >3,500 m, doses 500-750 mg/day within 24 hours of altitude exposure appear to be the most effective for minimizing symptoms of AMS.
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Affiliation(s)
- Claudia M Toussaint
- Oak Ridge Institute for Science and Education, Oak Ridge, Tennessee, USA.,Thermal and Mountain Medicine Division, U.S. Army Research Institute of Environmental Medicine, Natick, Massachusetts, USA
| | - Robert W Kenefick
- Thermal and Mountain Medicine Division, U.S. Army Research Institute of Environmental Medicine, Natick, Massachusetts, USA
| | - Frank A Petrassi
- Thermal and Mountain Medicine Division, U.S. Army Research Institute of Environmental Medicine, Natick, Massachusetts, USA
| | - Stephen R Muza
- Thermal and Mountain Medicine Division, U.S. Army Research Institute of Environmental Medicine, Natick, Massachusetts, USA
| | - Nisha Charkoudian
- Thermal and Mountain Medicine Division, U.S. Army Research Institute of Environmental Medicine, Natick, Massachusetts, USA
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Ji Q, Zhang Y, Zhang H, Liu J, Cao C, Yuan Z, Ma Q, Zhang W. Effects of β-adrenoceptor activation on haemodynamics during hypoxic stress in rats. Exp Physiol 2020; 105:1660-1668. [PMID: 32706493 DOI: 10.1113/ep088669] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2020] [Accepted: 07/23/2020] [Indexed: 11/08/2022]
Abstract
NEW FINDINGS What is the central question of this study? The acute hypoxic compensatory reaction is based on haemodynamic changes, and β-adrenoceptors are involved in haemodynamic regulation. What is the role of β-adrenoceptors in haemodynamics during hypoxic exposure? What is the main finding and its importance? Activation of β2 -adrenoceptors attenuates the increase in pulmonary artery pressure during hypoxic exposure. This compensatory reaction activated by β2 -adrenoceptors during hypoxic stress is very important to maintain the activities of normal life. ABSTRACT The acute hypoxic compensatory reaction is accompanied by haemodynamic changes. We monitored the haemodynamic changes in rats undergoing acute hypoxic stress and applied antagonists of β-adrenoceptor (β-ARs) subtypes to reveal the regulatory role of β-ARs on haemodynamics. Sprague-Dawley rats were randomly divided into control, atenolol (β1 -AR antagonist), ICI 118,551 (β2 -AR antagonist) and propranolol (non-selective β-AR antagonist) groups. Rats were continuously recorded for changes in haemodynamic indexes for 10 min after administration. Then, a hypoxic ventilation experiment [15% O2 , 2200 m a.sl., 582 mmHg (0.765 Pa), P O 2 87.3 mmHg; Xining, China] was conducted, and the indexes were monitored for 5 min after induction of hypoxia. Plasma catecholamine concentrations were also measured. We found that, during normoxia, the mean arterial pressure, heart rate, ascending aortic blood flow and pulmonary artery pressure were reduced in the propranolol and atenolol groups. Catecholamine concentrations were increased significantly in the atenolol group compared with the control group. During hypoxia, mean arterial pressure and total peripheral resistance were decreased in the control, propranolol and ICI 118,551 groups. Pulmonary arterial pressure and pulmonary vascular resistance were increased in the propranolol and ICI 118,551 groups. During hypoxia, catecholamine concentrations were increased significantly in the control group, but decreased in β-AR antagonist groups. In conclusion, the β2 -AR is involved in regulation of pulmonary haemodynamics in the acute hypoxic compensatory reaction, and the activation of β2 -ARs attenuates the increase in pulmonary arterial pressure during hypoxic stress. This compensatory reaction activated by β2 -ARs during hypoxic stress is very important to maintain activities of normal life.
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Affiliation(s)
- Qiaorong Ji
- Department of Basic Medicine, Medical College of Qinghai University, No.16 kunlun road, Xining, Qinghai, 810001, China.,Pathophysiology Laboratory, The Key Laboratory of Science and Technology for High Altitude Medicine, No.16 kunlun road, Xining, Qinghai, 810001, China
| | - Yu Zhang
- Department of Basic Medicine, Medical College of Qinghai University, No.16 kunlun road, Xining, Qinghai, 810001, China
| | - Huan Zhang
- Department of Pathology, Weinan Central Hospital, Shengli street, Weinan, Shaanxi, 714000, China
| | - Jie Liu
- Department of Basic Medicine, Medical College of Qinghai University, No.16 kunlun road, Xining, Qinghai, 810001, China.,Pathophysiology Laboratory, The Key Laboratory of Science and Technology for High Altitude Medicine, No.16 kunlun road, Xining, Qinghai, 810001, China
| | - Chengzhu Cao
- Department of Basic Medicine, Medical College of Qinghai University, No.16 kunlun road, Xining, Qinghai, 810001, China.,Pathophysiology Laboratory, The Key Laboratory of Science and Technology for High Altitude Medicine, No.16 kunlun road, Xining, Qinghai, 810001, China
| | - Zhouyang Yuan
- Department of Basic Medicine, Medical College of Qinghai University, No.16 kunlun road, Xining, Qinghai, 810001, China.,Pathophysiology Laboratory, The Key Laboratory of Science and Technology for High Altitude Medicine, No.16 kunlun road, Xining, Qinghai, 810001, China
| | - Qianqian Ma
- Department of Basic Medicine, Medical College of Qinghai University, No.16 kunlun road, Xining, Qinghai, 810001, China.,Pathophysiology Laboratory, The Key Laboratory of Science and Technology for High Altitude Medicine, No.16 kunlun road, Xining, Qinghai, 810001, China
| | - Wei Zhang
- Department of Basic Medicine, Medical College of Qinghai University, No.16 kunlun road, Xining, Qinghai, 810001, China.,Pathophysiology Laboratory, The Key Laboratory of Science and Technology for High Altitude Medicine, No.16 kunlun road, Xining, Qinghai, 810001, China
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11
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Network Pharmacology-Based Analysis of the Pharmacological Mechanisms of Aloperine on Cardiovascular Disease. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2020; 2020:5180716. [PMID: 32733582 PMCID: PMC7376400 DOI: 10.1155/2020/5180716] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Revised: 05/25/2020] [Accepted: 06/18/2020] [Indexed: 12/24/2022]
Abstract
Background Aloperine is an active component of Sophora alopecuroides Linn, which has been extensively applied for the treatment of cardiovascular disease (CVD). However, our current understanding of the molecular mechanisms supporting the effects of aloperine on CVD remains unclear. Methods Systematic network pharmacology was conducted to provide testable hypotheses about pharmacological mechanisms of the protective effects of aloperine against CVD. Detailed structure was obtained from Traditional Chinese Medicines Integrated Database (TCMID). Target genes of aloperine against CVD were collected from SwissTargetPrediction, DrugBank database, and Online Mendelian Inheritance in Man (OMIM) database. Gene Ontology (GO) enrichment analysis, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway performance, and network construction were adopted to explore common target genes. Results Our findings showed that 25 candidate targets were the interacting genes between aloperine and CVD. GO analysis revealed biological process, cellular component, and molecular function of these target genes. More importantly, the majority of enrichment pathways was found to be highly associated with the nitrogen metabolism by KEGG analysis. Core genes particularly in nitrogen metabolism pathway including carbonic anhydrase (CA) III, CA IV, CA VA, CA VB, CA VI, CA VII, CA IX, CA XII, and CA XIV can be modulated by aloperine in the nitrogen metabolism. Conclusion Our work revealed the pharmacological and molecular mechanisms of aloperine against CVD and provided a feasible tool to identify the pharmacological mechanisms of single active ingredient of traditional Chinese medicines.
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Duke JW, Beasley KM, Speros JP, Elliott JE, Laurie SS, Goodman RD, Futral E, Hawn JA, Lovering AT. Impaired pulmonary gas exchange efficiency, but normal pulmonary artery pressure increases, with hypoxia in men and women with a patent foramen ovale. Exp Physiol 2020; 105:1648-1659. [PMID: 32627890 DOI: 10.1113/ep088750] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Accepted: 06/30/2020] [Indexed: 01/07/2023]
Abstract
NEW FINDINGS What is the central question of this study? Do individuals with a patent foramen ovale (PFO+ ) have a larger alveolar-to-arterial difference in P O 2 ( A - a D O 2 ) than those without (PFO- ) and/or an exaggerated increase in pulmonary artery systolic pressure (PASP) in response to hypoxia? What is the main finding and its importance? PFO+ had a greater A - a D O 2 while breathing air, 16% and 14% O2 , but not 12% or 10% O2 . PASP increased equally in hypoxia between PFO+ and PFO- . These data suggest that PFO+ may not have an exaggerated acute increase in PASP in response to hypoxia. ABSTRACT Patent foramen ovale (PFO) is present in 30-40% of the population and is a potential source of right-to-left shunt. Accordingly, those with a PFO (PFO+ ) may have a larger alveolar-to-arterial difference in P O 2 ( A - a D O 2 ) than those without (PFO- ) in normoxia and with mild hypoxia. Likewise, PFO is associated with high-altitude pulmonary oedema, a condition known to have an exaggerated pulmonary pressure response to hypoxia. Thus, PFO+ may also have exaggerated pulmonary pressure increases in response to hypoxia. Therefore, the purposes of the present study were to systematically determine whether or not: (1) the A - a D O 2 was greater in PFO+ than in PFO- in normoxia and mild to severe hypoxia and (2) the increase in pulmonary artery systolic pressure (PASP) in response to hypoxia was greater in PFO+ than in PFO- . We measured arterial blood gases and PASP via ultrasound in healthy PFO+ (n = 15) and PFO- (n = 15) humans breathing air and 30 min after breathing four levels of hypoxia (16%, 14%, 12%, 10% O2 , randomized and balanced order) at rest. The A - a D O 2 was significantly greater in PFO+ compared to PFO- while breathing air (2.1 ± 0.7 vs. 0.4 ± 0.3 Torr), 16% O2 (1.8 ± 1.2 vs. 0.7 ± 0.8 Torr) and 14% O2 (2.3 ± 1.2 vs. 0.7 ± 0.6 Torr), but not 12% or 10% O2 . We found no effect of PFO on PASP at any level of hypoxia. We conclude that PFO influences pulmonary gas exchange efficiency with mild hypoxia, but not the acute increase in PASP in response to hypoxia.
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Affiliation(s)
- Joseph W Duke
- Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ, USA
| | - Kara M Beasley
- Department of Human Physiology, University of Oregon, Eugene, OR, USA
| | - Julia P Speros
- Department of Human Physiology, University of Oregon, Eugene, OR, USA
| | - Jonathan E Elliott
- VA Portland Health Care System, Portland, OR, USA.,Department of Neurology, Oregon Health and Science University, Portland, OR, USA
| | - Steven S Laurie
- KBR, Cardiovascular and Vision Laboratory, NASA Johnson Space Center, Houston, TX, USA
| | | | - Eben Futral
- Oregon Heart and Vascular Institute, Springfield, OR, USA
| | - Jerold A Hawn
- Oregon Heart and Vascular Institute, Springfield, OR, USA
| | - Andrew T Lovering
- Department of Human Physiology, University of Oregon, Eugene, OR, USA
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13
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Methazolamide in high-altitude illnesses. Eur J Pharm Sci 2020; 148:105326. [PMID: 32251722 DOI: 10.1016/j.ejps.2020.105326] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Revised: 03/26/2020] [Accepted: 03/26/2020] [Indexed: 11/24/2022]
Abstract
As a carbonic anhydrase inhibitor and a methylated lipophilic analogue of acetazolamide, Methazolamide has higher lipid solubility, less plasma protein binding and renal excretion, and fewer side effects, compared to acetazolamide. Methazolamide can increase systemic metabolic acidosis and sequentially improve ventilation and oxygenation level. The increased oxygenation level leads to reduced reactive oxygen species (ROS) production, relived cerebral edema, mitigated hypoxic pulmonary vasoconstriction, abrogated hypoxic fatigue, and decreased excessive erythrocytosis. In addition to the effect as a carbonic anhydrase inhibitor, methazolamide directly activates the transcription factor anti-oxidative nuclear factor-related factor 2 (Nrf2) and inhibits interleukin-1β (IL-1β) release. These pharmacological functions of methazolamide are beneficial for the prevention and treatment of high-altitude illnesses. Besides, methazolamide causes less fatigue side effects than acetazolamide does. It is also worth noting that several studies suggested that a lower dose of methazolamide has similar prophylaxis and treatment efficacy in acute mountain sickness (AMS) to a higher dose of acetazolamide. Given methazolamide's advantages over acetazolamide, methazolamide may thus represent an alternative for acetazolamide when taken for high-altitude illnesses prophylaxis and treatment. However, more in-depth clinical trials are needed to fully evaluate this efficacy of methazolamide.
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Subudhi AW, Evero O, Reitinger J, Davis C, Gronewold J, Nichols AJ, Van‐Houten SJ, Roach RC. Combined methazolamide and theophylline improves oxygen saturation but not exercise performance or altitude illness in acute hypobaric hypoxia. Exp Physiol 2020; 106:117-125. [DOI: 10.1113/ep088461] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Accepted: 04/29/2020] [Indexed: 01/04/2023]
Affiliation(s)
- Andrew W. Subudhi
- Altitude Research Center University of Colorado Anschutz Medical Campus Aurora CO USA
- Department of Human Physiology and Nutrition University of Colorado Colorado Springs Colorado Springs CO USA
| | - Oghenero Evero
- Altitude Research Center University of Colorado Anschutz Medical Campus Aurora CO USA
| | - Jeremy Reitinger
- Altitude Research Center University of Colorado Anschutz Medical Campus Aurora CO USA
| | - Christopher Davis
- Altitude Research Center University of Colorado Anschutz Medical Campus Aurora CO USA
| | - Jeffrey Gronewold
- Altitude Research Center University of Colorado Anschutz Medical Campus Aurora CO USA
| | - Andrew J. Nichols
- Altitude Research Center University of Colorado Anschutz Medical Campus Aurora CO USA
| | | | - Robert C. Roach
- Altitude Research Center University of Colorado Anschutz Medical Campus Aurora CO USA
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15
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Leacy JK, Day TA, O'Halloran KD. Carbonic anhydrase inhibition and chemoreflex control of breathing: A litmus test for methazolamide as a viable alternative to acetazolamide. Exp Physiol 2020; 105:230-231. [DOI: 10.1113/ep088238] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Accepted: 11/08/2019] [Indexed: 11/08/2022]
Affiliation(s)
- Jack K. Leacy
- Department of PhysiologySchool of MedicineCollege of Medicine & HealthUniversity College Cork Cork Ireland
| | - Trevor A. Day
- Department of BiologyMount Royal University Calgary Alberta Canada
| | - Ken D. O'Halloran
- Department of PhysiologySchool of MedicineCollege of Medicine & HealthUniversity College Cork Cork Ireland
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Teppema LJ, Boulet LM, Hackett HK, Dominelli PB, Cheyne WS, Dominelli GS, Swenson ER, Foster GE. Influence of methazolamide on the human control of breathing: A comparison to acetazolamide. Exp Physiol 2019; 105:293-301. [PMID: 31595565 DOI: 10.1113/ep088058] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Accepted: 10/04/2019] [Indexed: 01/15/2023]
Abstract
NEW FINDINGS What is the central question of this study? Acetazolamide and methazolamide both reduce hypoxic pulmonary vasoconstriction equally, but methazolamide does not impair skeletal muscle function. The effect of methazolamide on respiratory control in humans is not yet known. What is the main finding and its importance? Similar to acetazolamide after chronic oral administration, methazolamide causes a metabolic acidosis and shifts the ventilatory CO2 response curve leftwards without reducing O2 sensitivity. The change in ventilation over the change in log P O 2 provides a more accurate measure of hypoxic sensitivity than the change in ventilation over the change in arterial oxyhaemoglobin saturation. ABSTRACT Acetazolamide is used to prevent/treat acute mountain sickness and both central and obstructive sleep apnoea. Methazolamide, like acetazolamide, reduces hypoxic pulmonary vasoconstriction, but has fewer side-effects, including less impairment of skeletal muscle function. Given that the effects of methazolamide on respiratory control in humans are unknown, we compared the effects of oral methazolamide and acetazolamide on ventilatory control and determined the ventilation-log P O 2 relationship in humans. In a double-blind, placebo-controlled, randomized cross-over design, we studied the effects of acetazolamide (250 mg three times daily), methazolamide (100 mg twice daily) and placebo in 14 young male subjects who were exposed to 7 min of normoxic hypercapnia and to three levels of eucapnia and hypercapnic hypoxia. With placebo, methazolamide and acetazolamide, the CO2 sensitivities were 2.39 ± 1.29, 3.27 ± 1.82 and 2.62 ± 1.79 l min-1 mmHg-1 (n.s.) and estimated apnoeic thresholds 32 ± 3, 28 ± 3 and 26 ± 3 mmHg, respectively (P < 0.001, placebo versus methazolamide and acetazolamide). The relationship between ventilation ( V ̇ I ) and log P O 2 (using arterialized venous P O 2 in hypoxia) was linear, and neither agent influenced the relationship between hypoxic sensitivity ( Δ V ̇ I / Δ log P O 2 ) and arterial [H+ ]. Using Δ V ̇ I / Δ log P O 2 rather than Δ V ̇ I /Δ arterial oxyhaemoglobin saturation enables a more accurate estimation of oxygenation and ventilatory control in metabolic acidosis/alkalosis when right- or leftward shifts of the oxyhaemoglobin saturation curve occur. Given that acetazolamide and methazolamide have similar effects on ventilatory control, methazolamide might be preferred for indications requiring the use of a carbonic anhydrase inhibitor, avoiding some of the negative side-effects of acetazolamide.
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Affiliation(s)
- Luc J Teppema
- Department of Anesthesiology, Leiden University Medical Center, Leiden, The Netherlands
| | - Lindsey M Boulet
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Science, University of British Columbia, Kelowna, BC, Canada
| | - Heather K Hackett
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Science, University of British Columbia, Kelowna, BC, Canada
| | - Paolo B Dominelli
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Science, University of British Columbia, Kelowna, BC, Canada.,Department of Kinesiology, University of Waterloo, Waterloo, ON, Canada
| | - William S Cheyne
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Science, University of British Columbia, Kelowna, BC, Canada
| | - Giulio S Dominelli
- Southern Medical Program, University of British Columbia, Kelowna, BC, Canada
| | - Erik R Swenson
- Division of Pulmonary & Critical Care Medicine, VA Puget Sound Health Care System, University of Washington, Seattle, WA, USA
| | - Glen E Foster
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Science, University of British Columbia, Kelowna, BC, Canada
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