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Diekman CO, Thomas PJ, Wilson CG. COVID-19 and silent hypoxemia in a minimal closed-loop model of the respiratory rhythm generator. BIOLOGICAL CYBERNETICS 2024; 118:145-163. [PMID: 38884785 PMCID: PMC11289179 DOI: 10.1007/s00422-024-00989-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Accepted: 03/28/2024] [Indexed: 06/18/2024]
Abstract
Silent hypoxemia, or "happy hypoxia," is a puzzling phenomenon in which patients who have contracted COVID-19 exhibit very low oxygen saturation ( SaO 2 < 80%) but do not experience discomfort in breathing. The mechanism by which this blunted response to hypoxia occurs is unknown. We have previously shown that a computational model of the respiratory neural network (Diekman et al. in J Neurophysiol 118(4):2194-2215, 2017) can be used to test hypotheses focused on changes in chemosensory inputs to the central pattern generator (CPG). We hypothesize that altered chemosensory function at the level of the carotid bodies and/or the nucleus tractus solitarii are responsible for the blunted response to hypoxia. Here, we use our model to explore this hypothesis by altering the properties of the gain function representing oxygen sensing inputs to the CPG. We then vary other parameters in the model and show that oxygen carrying capacity is the most salient factor for producing silent hypoxemia. We call for clinicians to measure hematocrit as a clinical index of altered physiology in response to COVID-19 infection.
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Affiliation(s)
- Casey O Diekman
- Department of Mathematical Sciences, New Jersey Institute of Technology, University Heights, Newark, NJ, 07102, USA.
| | - Peter J Thomas
- Department of Mathematics, Applied Mathematics and Statistics, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH, 44106, USA
| | - Christopher G Wilson
- Department of Pediatrics and Basic Sciences, Lawrence D. Longo, MD Center for Perinatal Biology, Loma Linda University, 11223 Campus St, Loma Linda, CA, 92350, USA
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2
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Bertilacchi MS, Piccarducci R, Celi A, Germelli L, Romei C, Bartholmai B, Barbieri G, Giacomelli C, Martini C. Blood oxygenation state in COVID-19 patients: Unexplored role of 2,3-bisphosphoglycerate. Biomed J 2024:100723. [PMID: 38583585 DOI: 10.1016/j.bj.2024.100723] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Revised: 03/16/2024] [Accepted: 03/29/2024] [Indexed: 04/09/2024] Open
Abstract
BACKGROUND COVID-19 reduces lung functionality causing a decrease of blood oxygen levels (hypoxemia) often related to a decreased cellular oxygenation (hypoxia). Besides lung injury, other factors are implicated in the regulation of oxygen availability such as pH, partial arterial carbon dioxide tension (PaCO2), temperature, and erythrocytic 2,3-bisphosphoglycerate (2,3-BPG) levels, all factors affecting hemoglobin saturation curve. However, few data are currently available regarding the 2,3-BPG modulation in SARS-CoV-2 affected patients at the hospital admission. MATERIAL AND METHODS Sixty-eight COVID-19 patients were enrolled at hospital admission. The lung involvement was quantified using chest-Computer Tomography (CT) analysed with automatic software (CALIPER). Haemoglobin concentrations, glycemia, and routine analysis were evaluated in the whole blood, while partial arterial oxygen tension (PaO2), PaCO2, pH, and HCO3- were assessed by arterial blood gas analysis. 2,3-BPG levels were assessed by specific immunoenzymatic assays in RBCs. RESULTS A higher percentage of interstitial lung disease (ILD) and vascular pulmonary-related structure (VRS) volume on chest-CT quantified with CALIPER had been found in COVID-19 patients with a worse disease outcome (R = 0.4342; and R = 0.3641, respectively). Furthermore, patients with lower PaO2 showed an imbalanced acid-base equilibrium (pH, p = 0.0208; PaCO2, p = 0.0496) and a higher 2,3-BPG levels (p = 0.0221). The 2,3-BPG levels were also lower in patients with metabolic alkalosis (p = 0.0012 vs. no alkalosis; and p = 0.0383 vs. respiratory alkalosis). CONCLUSIONS Overall, the data reveal a different pattern of activation of blood oxygenation compensatory mechanisms reflecting a different course of the COVID-19 disease specifically focusing on 2,3-BPG modulation.
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Affiliation(s)
| | | | - Alessandro Celi
- Department of Surgical, Medical and Molecular Pathology and Critical Care, University of Pisa, Pisa, 56126, Italy
| | | | - Chiara Romei
- Department of Radiology, Pisa University Hospital, Pisa, Italy.
| | - Brian Bartholmai
- Division of Radiology, Mayo Clinic Rochester, Rochester, MN, USA
| | - Greta Barbieri
- Department of Emergency Medicine Department, Pisa University Hospital, Italy
| | | | - Claudia Martini
- Department of Pharmacy, University of Pisa, 56126, Pisa, Italy
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3
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Diekman CO, Thomas PJ, Wilson CG. COVID-19 and silent hypoxemia in a minimal closed-loop model of the respiratory rhythm generator. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.19.536507. [PMID: 37131753 PMCID: PMC10153159 DOI: 10.1101/2023.04.19.536507] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Silent hypoxemia, or 'happy hypoxia', is a puzzling phenomenon in which patients who have contracted COVID-19 exhibit very low oxygen saturation (SaO2 < 80%) but do not experience discomfort in breathing. The mechanism by which this blunted response to hypoxia occurs is unknown. We have previously shown that a computational model (Diekman et al., 2017, J. Neurophysiol) of the respiratory neural network can be used to test hypotheses focused on changes in chemosensory inputs to the central pattern generator (CPG). We hypothesize that altered chemosensory function at the level of the carotid bodies and/or the nucleus tractus solitarii are responsible for the blunted response to hypoxia. Here, we use our model to explore this hypothesis by altering the properties of the gain function representing oxygen sensing inputs to the CPG. We then vary other parameters in the model and show that oxygen carrying capacity is the most salient factor for producing silent hypoxemia. We call for clinicians to measure hematocrit as a clinical index of altered physiology in response to COVID-19 infection.
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Affiliation(s)
- Casey O Diekman
- Department of Mathematical Sciences, New Jersey Institute of Technology, University Heights, Newark NJ 07102
| | - Peter J Thomas
- Department of Mathematics, Applied Mathematics and Statistics, Case Western Reserve University, 10900 Euclid Avenue, Cleveland OH 44106
| | - Christopher G Wilson
- Department of Pediatrics & Basic Sciences, Loma Linda University, Lawrence D. Longo, MD Center for Perinatal Biology, 11223 Campus St, Loma Linda CA 92350
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4
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Kosenko E, Tikhonova L, Alilova G, Montoliu C. Erythrocytes Functionality in SARS-CoV-2 Infection: Potential Link with Alzheimer's Disease. Int J Mol Sci 2023; 24:5739. [PMID: 36982809 PMCID: PMC10051442 DOI: 10.3390/ijms24065739] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Revised: 03/14/2023] [Accepted: 03/15/2023] [Indexed: 03/19/2023] Open
Abstract
Coronavirus disease 2019 (COVID-19) is a rapidly spreading acute respiratory infection caused by SARS-CoV-2. The pathogenesis of the disease remains unclear. Recently, several hypotheses have emerged to explain the mechanism of interaction between SARS-CoV-2 and erythrocytes, and its negative effect on the oxygen-transport function that depends on erythrocyte metabolism, which is responsible for hemoglobin-oxygen affinity (Hb-O2 affinity). In clinical settings, the modulators of the Hb-O2 affinity are not currently measured to assess tissue oxygenation, thereby providing inadequate evaluation of erythrocyte dysfunction in the integrated oxygen-transport system. To discover more about hypoxemia/hypoxia in COVID-19 patients, this review highlights the need for further investigation of the relationship between biochemical aberrations in erythrocytes and oxygen-transport efficiency. Furthermore, patients with severe COVID-19 experience symptoms similar to Alzheimer's, suggesting that their brains have been altered in ways that increase the likelihood of Alzheimer's. Mindful of the partly assessed role of structural, metabolic abnormalities that underlie erythrocyte dysfunction in the pathophysiology of Alzheimer's disease (AD), we further summarize the available data showing that COVID-19 neurocognitive impairments most probably share similar patterns with known mechanisms of brain dysfunctions in AD. Identification of parameters responsible for erythrocyte function that vary under SARS-CoV-2 may contribute to the search for additional components of progressive and irreversible failure in the integrated oxygen-transport system leading to tissue hypoperfusion. This is particularly relevant for the older generation who experience age-related disorders of erythrocyte metabolism and are prone to AD, and provide an opportunity for new personalized therapies to control this deadly infection.
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Affiliation(s)
- Elena Kosenko
- Institute of Theoretical and Experimental Biophysics of Russian Academy of Sciences, 142290 Pushchino, Russia
| | - Lyudmila Tikhonova
- Institute of Theoretical and Experimental Biophysics of Russian Academy of Sciences, 142290 Pushchino, Russia
| | - Gubidat Alilova
- Institute of Theoretical and Experimental Biophysics of Russian Academy of Sciences, 142290 Pushchino, Russia
| | - Carmina Montoliu
- Hospital Clinico Research Foundation, INCLIVA Health Research Institute, 46010 Valencia, Spain
- Pathology Department, Faculty of Medicine, University of Valencia, 46010 Valencia, Spain
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Bergamaschi G, Barteselli C, Del Rio V, Borrelli de Andreis F, Pellegrino I, Mengoli C, Miceli E, Colaneri M, Zuccaro V, Di Stefano M, Bruno R, Di Sabatino A, Achilli G, Alimenti E, Alunno G, Antoci V, Aprile M, Argelli A, Aronico N, Ballesio A, Bellini G, Berbenni A, Bertolino G, Bianchi PI, Biserni S, Bonfichi A, Bosoni T, Brattoli M, Calabretta F, Callisti M, Cambiè G, Canta R, Canu P, Cebrelli C, Cecco A, Cicalini C, Clemente M, Clerici L, Codega S, Conca F, Coppola L, Costanzo F, Cremonte ME, Cresci R, Delliponti M, Del Rio V, Delogu C, Derosa G, Dionisi D, Di Terlizzi F, Dota M, Falaschi F, Fazzino E, Ferrami L, Ferrara S, Ferrari MG, Ferruccio N, Freddi G, Frenna C, Frigerio C, Fumoso F, Fusco A, Galeazzo A, Gaspari V, Gentile A, Giangreco A, Gori G, Grandi G, Gregorio V, Grimaldi P, Italia A, Lapia F, Latorre MA, Lenti MV, Lepore F, Lobello A, Lovati E, Lucotti PC, Lusetti F, Maimaris S, Mambella J, Martignoni A, Melazzini F, Mercanti C, Merli S, Moltisanti GC, Monti ME, Morbegno L, Mordà F, Mugellini A, Muggia C, Muscia R, Nardone A, Padovini L, Palumbo I, Parisi IM, Pecci A, Peroo GP, Petrucci C, Pieresca C, Pino G, Pitotti L, Poma S, Preti PS, Quadrelli A, Rascaroli A, Rigano G, Rossi CM, Rotola G, Ruggeri D, Russo MC, Sabatini U, Saglio S, Santacroce G, Savioli G, Savioli J, Scalia SS, Scalvini D, Shoval Y, Soffiantini C, Soriano S, Spadaro D, Staniscia A, Stefani D, Vai F, Varallo M, Vernero M. Impaired respiratory function reduces haemoglobin oxygen affinity in COVID-19. Br J Haematol 2023; 200:e44-e47. [PMID: 36572525 PMCID: PMC9880731 DOI: 10.1111/bjh.18620] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Revised: 11/21/2022] [Accepted: 12/09/2022] [Indexed: 12/28/2022]
Affiliation(s)
- Gaetano Bergamaschi
- Internal Medicine Unit, Fondazione IRCCS Policlinico San Matteo, Pavia, Italy
| | - Chiara Barteselli
- Internal Medicine Unit, Fondazione IRCCS Policlinico San Matteo, Pavia, Italy.,Department of Internal Medicine & Medical Therapy, University of Pavia, Pavia, Italy
| | - Virginia Del Rio
- Internal Medicine Unit, Fondazione IRCCS Policlinico San Matteo, Pavia, Italy.,Department of Internal Medicine & Medical Therapy, University of Pavia, Pavia, Italy
| | - Federica Borrelli de Andreis
- Internal Medicine Unit, Fondazione IRCCS Policlinico San Matteo, Pavia, Italy.,Department of Internal Medicine & Medical Therapy, University of Pavia, Pavia, Italy
| | - Ivan Pellegrino
- Internal Medicine Unit, Fondazione IRCCS Policlinico San Matteo, Pavia, Italy.,Department of Internal Medicine & Medical Therapy, University of Pavia, Pavia, Italy
| | - Caterina Mengoli
- Internal Medicine Unit, Fondazione IRCCS Policlinico San Matteo, Pavia, Italy
| | - Emanuela Miceli
- Internal Medicine Unit, Fondazione IRCCS Policlinico San Matteo, Pavia, Italy
| | - Marta Colaneri
- Division of Infectious and Tropical Diseases, Fondazione IRCCS Policlinico San Matteo, Pavia, Italy.,Department of Clinical Surgical Diagnostic & Pediatric Sciences, University of Pavia, Pavia, Italy
| | - Valentina Zuccaro
- Division of Infectious and Tropical Diseases, Fondazione IRCCS Policlinico San Matteo, Pavia, Italy
| | - Michele Di Stefano
- Internal Medicine Unit, Fondazione IRCCS Policlinico San Matteo, Pavia, Italy
| | - Raffaele Bruno
- Division of Infectious and Tropical Diseases, Fondazione IRCCS Policlinico San Matteo, Pavia, Italy.,Department of Clinical Surgical Diagnostic & Pediatric Sciences, University of Pavia, Pavia, Italy
| | - Antonio Di Sabatino
- Internal Medicine Unit, Fondazione IRCCS Policlinico San Matteo, Pavia, Italy.,Department of Internal Medicine & Medical Therapy, University of Pavia, Pavia, Italy
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Böning D, Kuebler WM, Vogel D, Bloch W. The oxygen dissociation curve of blood in COVID-19-An update. Front Med (Lausanne) 2023; 10:1098547. [PMID: 36923010 PMCID: PMC10008909 DOI: 10.3389/fmed.2023.1098547] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Accepted: 02/03/2023] [Indexed: 03/02/2023] Open
Abstract
An impressive effect of the infection with SARS-Co-19 is the impairment of oxygen uptake due to lung injury. The reduced oxygen diffusion may potentially be counteracted by an increase in oxygen affinity of hemoglobin. However, hypoxia and anemia associated with COVID-19 usually decrease oxygen affinity due to a rise in [2,3-bisphosphoglycerate]. As such, COVID-19 related changes in the oxygen dissociation curve may be critical for oxygen uptake and supply, but are hard to predict. A Pubmed search lists 14 publications on oxygen affinity in COVID-19. While some investigations show no changes, three large studies found an increased affinity that was related to a good prognosis. Exact causes remain unknown. The cause of the associated anemia in COVID-19 is under discussion. Erythrocytes with structural alterations of membrane and cytoskeleton have been observed, and virus binding to Band 3 and also to ACE2 receptors in erythroblasts has been proposed. COVID-19 presentation is moderate in many subjects suffering from sickle cell disease. A possible explanation is that COVID-19 counteracts the unfavorable large right shift of the oxygen dissociation curve in these patients. Under discussion for therapy are mainly affinity-increasing drugs.
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Affiliation(s)
- Dieter Böning
- Institute of Physiology, Charité Medical University of Berlin, Berlin, Germany
| | - Wolfgang M. Kuebler
- Institute of Physiology, Charité Medical University of Berlin, Berlin, Germany
| | - Dominik Vogel
- Klinik für Interdisziplinäre Intensivmedizin, Vivantes Humboldt-Klinikum, Berlin, Germany
| | - Wilhelm Bloch
- Department of Molecular and Cellular Sport Medicine, Institute of Cardiovascular Research and Sport Medicine, German Sport University Cologne, Cologne, Germany
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Ceruti S, Minotti B, Glotta A, Biggiogero M, Bona G, Marzano M, Greco P, Spagnoletti M, Garzoni C, Bendjelid K. Reply to Böning et al. Comment on “Ceruti et al. Temporal Changes in the Oxyhemoglobin Dissociation Curve of Critically Ill COVID-19 Patients. J. Clin. Med. 2022, 11, 788”. J Clin Med 2022; 11:jcm11154547. [PMID: 35956162 PMCID: PMC9369590 DOI: 10.3390/jcm11154547] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Revised: 07/26/2022] [Accepted: 07/29/2022] [Indexed: 12/10/2022] Open
Abstract
We would like to thank Böning et al. for all the important issues raised in the present commentary [...]
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Affiliation(s)
- Samuele Ceruti
- Department of Critical Care, Clinica Luganese Moncucco, 6900 Lugano, Switzerland
- Correspondence: or ; Tel.: +41-91-960-81-11
| | - Bruno Minotti
- Emergency Department, St. Gallen Cantonal Hospital, 9000 St. Gallen, Switzerland
| | - Andrea Glotta
- Department of Critical Care, Clinica Luganese Moncucco, 6900 Lugano, Switzerland
| | - Maira Biggiogero
- Clinical Research Unit, Clinica Luganese Moncucco, 6900 Lugano, Switzerland
| | - Giovanni Bona
- Clinical Research Unit, Clinica Luganese Moncucco, 6900 Lugano, Switzerland
| | - Martino Marzano
- Department of Internal Medicine, Clinica Luganese Moncucco, 6900 Lugano, Switzerland
| | - Pietro Greco
- Emergency Department, Clinica Luganese Moncucco, 6900 Lugano, Switzerland
| | - Marco Spagnoletti
- Emergency Department, Clinica Luganese Moncucco, 6900 Lugano, Switzerland
| | - Christian Garzoni
- Department of Internal Medicine, Clinica Luganese Moncucco, 6900 Lugano, Switzerland
| | - Karim Bendjelid
- Intensive Care Division, Geneva University Hospitals, 1205 Geneva, Switzerland
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Comment on Ceruti et al. Temporal Changes in the Oxyhemoglobin Dissociation Curve of Critically Ill COVID-19 Patients. J. Clin. Med. 2022, 11, 788. J Clin Med 2022; 11:jcm11123376. [PMID: 35743447 PMCID: PMC9225162 DOI: 10.3390/jcm11123376] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Revised: 06/05/2022] [Accepted: 06/09/2022] [Indexed: 02/01/2023] Open
Abstract
Ceruti et al. describe in their article very low standard half saturation pressures (P50) in COVID-19 patients, calculated with the Dash et al. equations. By using the Hill equation and Severinghaus‘ coefficients we obtained normal values. The authors who do not present a pathophysiological cause for their results should explain this discrepancy. Independent of the absolute values a continuous moderate decrease of P50 in the surviving patients might be of clinical importance.
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