Hemodynamics and Microvascular Oxygenation Under Intermittent Hypoxia to Simulate Sleep Apnea

Hemodynamics and Microvascular Oxygenation Under Intermittent Hypoxia to Simulate Sleep Apnea | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Article Hemodynamics and Microvascular Oxygenation Under Intermittent Hypoxia to Simulate Sleep Apnea Pedro Cabrales This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7745455/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted You are reading this latest preprint version Abstract Obstructive sleep apnea (OSA) is characterized by recurrent episodes of intermittent hypoxia (IH). In this study, we investigated how cyclic IH (21%/10% O₂) acutely alters systemic hemodynamics and microvascular vascular tone, hemodynamics, and oxygen transport compared to the control (21%/21% O₂). Using a dorsal window chamber model on unanesthetized Golden Syrian hamsters, we applied 30-second oxygen cycling for 60 minutes. Microvascular oxygen saturation was continuously monitored using hyperspectral imaging (HSI), and vessel diameter, red blood cell velocity, functional capillary density (FCD), and vascular resistance were quantified through intravital microscopy. Animals exposed to IH exhibited significant reductions in mean arterial pressure and arterial oxygen saturation, along with increased heart rate and blood lactate. Microvascular SO₂ declined rapidly in the microcirculation and stabilized after 8 mins. Arteriolar blood flow decreased, and FCD was significantly reduced relative to both baseline and control. Despite a decrease in vascular resistance, vasodilatory compensation was insufficient and resulted in decreased oxygen delivery (DO₂) and oxygen extraction (VO₂) to tissues. The oxygen extraction ratio increased, suggesting a limited capacity to offset hypoxic stress. These findings demonstrate that cyclic IH significantly disrupts peripheral microcirculatory flow and oxygenation, highlighting the relevance of IH models in assessing oxygen transport during OSA. Biological sciences/Physiology/Circulation Biological sciences/Physiology/Cardiovascular biology/Cardiovascular diseases/Vascular diseases Full Text Additional Declarations There is NO Competing Interest. Cite Share Download PDF Status: Under Review Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-7745455","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":526108215,"identity":"5a0a7151-0fd2-478a-9543-6b28480e02cb","order_by":0,"name":"Pedro Cabrales","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAzUlEQVRIiWNgGAWjYHACNiC2YGBgb4CyDxCnRYKBgecAyVokEojUYs5++NnjihoJOfmZbww//ihjkOO7kYBfi2VPmrnhmWMSxga3c4ylec4xGEsS0mJwg8FMsoFNInGDdI4ZM2MbQ+IGwlrYv0k2/JOonz/zjBnjzzaGeiK08JhJNrYB/Q5kMPC2MSQYEPZLTrlhY5+E4YYzacVAv0gYzjzzAL8Wc/bj2x42fLORl28/vBEYYjbyfMcJOQyNL4FfOTYto2AUjIJRMAowAQAUeEDvTH9cegAAAABJRU5ErkJggg==","orcid":"","institution":"Univserity of California San Diego","correspondingAuthor":true,"prefix":"","firstName":"Pedro","middleName":"","lastName":"Cabrales","suffix":""}],"badges":[],"createdAt":"2025-09-29 22:00:10","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-7745455/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-7745455/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":94817264,"identity":"dc5ed046-88a5-4cdc-af27-ce8c0b32cddb","added_by":"auto","created_at":"2025-10-31 05:07:20","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":861513,"visible":true,"origin":"","legend":"","description":"","filename":"MappingMicrovascularOxyandHemodynamicsIH.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7745455/v1/364ed3f63b883900c5f76d62.pdf"},{"id":94817263,"identity":"692d201d-ed15-4285-873a-aaeb65c8c02a","added_by":"auto","created_at":"2025-10-31 05:07:20","extension":"json","order_by":1,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":3472,"visible":true,"origin":"","legend":"","description":"","filename":"COMMSBIO259534.json","url":"https://assets-eu.researchsquare.com/files/rs-7745455/v1/f4382ad4557ed4d7a4f31c02.json"},{"id":94826484,"identity":"fc9b2294-5a72-44ef-8a6b-761110edc85f","added_by":"auto","created_at":"2025-10-31 06:51:50","extension":"pdf","order_by":1,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":812001,"visible":true,"origin":"","legend":"Article File","description":"","filename":"MappingMicrovascularOxyandHemodynamicsIH.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7745455/v1_covered_4bcf960b-7f87-4407-a871-fe3e7286bb8d.pdf"}],"financialInterests":"There is \u003cb\u003eNO\u003c/b\u003e Competing Interest.","formattedTitle":"Hemodynamics and Microvascular Oxygenation Under Intermittent Hypoxia to Simulate Sleep Apnea","fulltext":[],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":false,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":true,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":true,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"nature-portfolio","isNatureJournal":true,"hasQc":false,"allowDirectSubmit":false,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"","title":"Nature Portfolio","twitterHandle":"","acdcEnabled":false,"dfaEnabled":false,"editorialSystem":"ejp","reportingPortfolio":"","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"","lastPublishedDoi":"10.21203/rs.3.rs-7745455/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7745455/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"Obstructive sleep apnea (OSA) is characterized by recurrent episodes of intermittent hypoxia (IH). In this study, we investigated how cyclic IH (21%/10% O₂) acutely alters systemic hemodynamics and microvascular vascular tone, hemodynamics, and oxygen transport compared to the control (21%/21% O₂). Using a dorsal window chamber model on unanesthetized Golden Syrian hamsters, we applied 30-second oxygen cycling for 60 minutes. Microvascular oxygen saturation was continuously monitored using hyperspectral imaging (HSI), and vessel diameter, red blood cell velocity, functional capillary density (FCD), and vascular resistance were quantified through intravital microscopy. Animals exposed to IH exhibited significant reductions in mean arterial pressure and arterial oxygen saturation, along with increased heart rate and blood lactate. Microvascular SO₂ declined rapidly in the microcirculation and stabilized after 8 mins. Arteriolar blood flow decreased, and FCD was significantly reduced relative to both baseline and control. Despite a decrease in vascular resistance, vasodilatory compensation was insufficient and resulted in decreased oxygen delivery (DO₂) and oxygen extraction (VO₂) to tissues. The oxygen extraction ratio increased, suggesting a limited capacity to offset hypoxic stress. 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