Adipose-Derived Stromal Cell Extracellular Vesicles Promote Fistula Healing in Rat and Pig Models of Chronic Gastrocutaneous Fistulae Following Sleeve Gastrectomy

Adipose-Derived Stromal Cell Extracellular Vesicles Promote Fistula Healing in Rat and Pig Models of Chronic Gastrocutaneous Fistulae Following Sleeve Gastrectomy | 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 Research Article Adipose-Derived Stromal Cell Extracellular Vesicles Promote Fistula Healing in Rat and Pig Models of Chronic Gastrocutaneous Fistulae Following Sleeve Gastrectomy Arthur Berger, Guillaume Pere, Anna Sebbagh, Matthieu Bruzzi, and 14 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-9139067/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 6 You are reading this latest preprint version Abstract Background: Gastrocutaneous fistulae following sleeve gastrectomy represent a serious complication associated with prolonged and complex management. To explore innovative therapeutic options, we aimed to develop representative and reproducible animal models to evaluate the potential of extracellular vesicles (EVs) derived from adipose-derived stromal cells (ADSCs). Design: Chronic gastrocutaneous fistulae were surgically induced following sleeve gastrectomy in both Wistar rats and Large-White pigs. In the rat model, animals received local administration of either saline (control, n=8), thermoresponsive hydrogel alone (gel, n=8), ADSC-derived EVs (n=8), EVs combined with hydrogel (EVG, n=8), or ADSCs themselves (n=7). In the porcine model, the effect of EVG (n=8) was compared to gel (n=8) and control (n=8). The primary endpoint was complete healing of the external orifice, marked by cessation of fistula output. Fistula healing was also assessed using radiological and histological criteria. Results: Chronic gastrocutaneous fistula models were successfully developed in both species. In rats, external healing occurred in 1/8 (control), 2/8 (gel), 7/8 (EV), 5/8 (EVG), and 4/7 (ADSC) animals. Healing rates were significantly higher in the EV group compared to control (p=0.01) and gel (p=0.041). Similarly, in pigs, EVG treatment showed significantly improved healing compared to control (p=0.01) and gel (p=0.041). Secondary assessments supported enhanced fistula tract closure in the EV and EVG groups. Conclusion: We describe the first validated animal models of chronic gastrocutaneous fistulae following sleeve gastrectomy and provide a proof-of-concept for the therapeutic benefit of ADSC-derived EVs, especially when combined with a thermoresponsive hydrogel. · Extracellular vesicles improve closure of gastrocutaneous fistulae. · Efficacy demonstrated in rat and pig sleeve gastrectomy models. · Novel preclinical models of gastrocutaneous fistula are described. · Adipose stromal cell EVs show potential for fistula treatment. Full Text Additional Declarations Competing interest reported. Florence Gazeau, Amanda Karine Andriola Silva, Claire Wilhelm and Gabriel Rahmi are co-founders of the spin-off Evora Biosciences. Amanda Karine Andriola Silva and Claire Wilhelm are co-founders of the spin-off EverZom. The other authors have no conflicts to declare. Supplementary Files Supplementarymaterialandmethods.docx Supplementarytablesandfigures.docx ARRIVEchecklist.docx Cite Share Download PDF Status: Under Review Version 1 posted Reviews received at journal 18 May, 2026 Reviewers agreed at journal 13 May, 2026 Reviewers invited by journal 15 Apr, 2026 Editor assigned by journal 22 Mar, 2026 Submission checks completed at journal 19 Mar, 2026 First submitted to journal 16 Mar, 2026 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-9139067","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":624640529,"identity":"69f074e6-2725-4f2f-a743-de7f76713f3c","order_by":0,"name":"Arthur Berger","email":"data:image/png;base64,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","orcid":"","institution":"Université Paris Cité","correspondingAuthor":true,"prefix":"","firstName":"Arthur","middleName":"","lastName":"Berger","suffix":""},{"id":624640530,"identity":"6e4be919-c08b-4646-8391-166796e0b68d","order_by":1,"name":"Guillaume Pere","email":"","orcid":"","institution":"Université Paris Cité","correspondingAuthor":false,"prefix":"","firstName":"Guillaume","middleName":"","lastName":"Pere","suffix":""},{"id":624640531,"identity":"83a90511-ed41-4fc3-8936-0869bac11812","order_by":2,"name":"Anna Sebbagh","email":"","orcid":"","institution":"Université Paris Cité","correspondingAuthor":false,"prefix":"","firstName":"Anna","middleName":"","lastName":"Sebbagh","suffix":""},{"id":624640532,"identity":"cc72b1be-38ac-4d1f-80ed-78b5c4d3b1d9","order_by":3,"name":"Matthieu Bruzzi","email":"","orcid":"","institution":"Université Paris Cité","correspondingAuthor":false,"prefix":"","firstName":"Matthieu","middleName":"","lastName":"Bruzzi","suffix":""},{"id":624640533,"identity":"29ce77f1-9cef-47d2-9a69-d0ebbdad7992","order_by":4,"name":"Amaury D'Angelo","email":"","orcid":"","institution":"Centre Hospitalier Universitaire de Bordeaux","correspondingAuthor":false,"prefix":"","firstName":"Amaury","middleName":"","lastName":"D'Angelo","suffix":""},{"id":624640534,"identity":"cdab6e9b-a391-4913-b19d-5937cbf6aa33","order_by":5,"name":"Hadrien Alric","email":"","orcid":"","institution":"Université Paris Cité","correspondingAuthor":false,"prefix":"","firstName":"Hadrien","middleName":"","lastName":"Alric","suffix":""},{"id":624640535,"identity":"d8177211-4849-4eb1-a3e3-38bdf09c3175","order_by":6,"name":"Thomas Viel","email":"","orcid":"","institution":"Université Paris Cité","correspondingAuthor":false,"prefix":"","firstName":"Thomas","middleName":"","lastName":"Viel","suffix":""},{"id":624640537,"identity":"4314c958-59b7-4a3e-b5b2-6a9707a4ee38","order_by":7,"name":"Irami Araújo-Filho","email":"","orcid":"","institution":"Federal University of Rio Grande do Norte","correspondingAuthor":false,"prefix":"","firstName":"Irami","middleName":"","lastName":"Araújo-Filho","suffix":""},{"id":624640538,"identity":"ccfd989e-fc8f-41b0-b6e9-3347ef870fcb","order_by":8,"name":"Marion Marty","email":"","orcid":"","institution":"Centre Hospitalier Universitaire de Bordeaux","correspondingAuthor":false,"prefix":"","firstName":"Marion","middleName":"","lastName":"Marty","suffix":""},{"id":624640540,"identity":"098c409e-86cc-403f-8cd6-2f28f2779f01","order_by":9,"name":"Corinne Lesaffre","email":"","orcid":"","institution":"Université Paris Cité","correspondingAuthor":false,"prefix":"","firstName":"Corinne","middleName":"","lastName":"Lesaffre","suffix":""},{"id":624640542,"identity":"058481fe-3b9a-41c3-88f0-276d8b817e66","order_by":10,"name":"Chloé Broudin","email":"","orcid":"","institution":"Assistance Publique - 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The other authors have no conflicts to declare.","formattedTitle":"Adipose-Derived Stromal Cell Extracellular Vesicles Promote Fistula Healing in Rat and Pig Models of Chronic Gastrocutaneous Fistulae Following Sleeve Gastrectomy","fulltext":[],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":false,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":true,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":true,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"obesity-surgery","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"obsu","sideBox":"Learn more about [Obesity Surgery](https://link.springer.com/journal/11695)","snPcode":"11695","submissionUrl":"https://submission.springernature.com/new-submission/11695/3","title":"Obesity Surgery","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"","lastPublishedDoi":"10.21203/rs.3.rs-9139067/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-9139067/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003eBackground:\u003c/strong\u003e Gastrocutaneous fistulae following sleeve gastrectomy represent a serious complication associated with prolonged and complex management. To explore innovative therapeutic options, we aimed to develop representative and reproducible animal models to evaluate the potential of extracellular vesicles (EVs) derived from adipose-derived stromal cells (ADSCs).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eDesign:\u003c/strong\u003e Chronic gastrocutaneous fistulae were surgically induced following sleeve gastrectomy in both Wistar rats and Large-White pigs. In the rat model, animals received local administration of either saline (control, n=8), thermoresponsive hydrogel alone (gel, n=8), ADSC-derived EVs (n=8), EVs combined with hydrogel (EVG, n=8), or ADSCs themselves (n=7). In the porcine model, the effect of EVG (n=8) was compared to gel (n=8) and control (n=8). The primary endpoint was complete healing of the external orifice, marked by cessation of fistula output. Fistula healing was also assessed using radiological and histological criteria.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eResults:\u003c/strong\u003e Chronic gastrocutaneous fistula models were successfully developed in both species. In rats, external healing occurred in 1/8 (control), 2/8 (gel), 7/8 (EV), 5/8 (EVG), and 4/7 (ADSC) animals. Healing rates were significantly higher in the EV group compared to control (p=0.01) and gel (p=0.041). Similarly, in pigs, EVG treatment showed significantly improved healing compared to control (p=0.01) and gel (p=0.041). Secondary assessments supported enhanced fistula tract closure in the EV and EVG groups.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConclusion:\u003c/strong\u003e We describe the first validated animal models of chronic gastrocutaneous fistulae following sleeve gastrectomy and provide a proof-of-concept for the therapeutic benefit of ADSC-derived EVs, especially when combined with a thermoresponsive hydrogel.\u003c/p\u003e\n\u003cp\u003e· Extracellular vesicles improve closure of gastrocutaneous fistulae.\u003c/p\u003e\n\u003cp\u003e· Efficacy demonstrated in rat and pig sleeve gastrectomy models.\u003c/p\u003e\n\u003cp\u003e· Novel preclinical models of gastrocutaneous fistula are described.\u003c/p\u003e\n\u003cp\u003e· Adipose stromal cell EVs show potential for fistula treatment.\u003c/p\u003e","manuscriptTitle":"Adipose-Derived Stromal Cell Extracellular Vesicles Promote Fistula Healing in Rat and Pig Models of Chronic Gastrocutaneous Fistulae Following Sleeve Gastrectomy","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-04-23 10:50:41","doi":"10.21203/rs.3.rs-9139067/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"editorInvitedReview","content":"","date":"2026-05-18T23:22:56+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"208752840099839145154773711455692399400","date":"2026-05-13T11:18:36+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2026-04-15T13:19:11+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2026-03-22T19:45:24+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2026-03-19T10:17:15+00:00","index":"","fulltext":""},{"type":"submitted","content":"Obesity Surgery","date":"2026-03-16T14:12:27+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"obesity-surgery","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"obsu","sideBox":"Learn more about [Obesity Surgery](https://link.springer.com/journal/11695)","snPcode":"11695","submissionUrl":"https://submission.springernature.com/new-submission/11695/3","title":"Obesity Surgery","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"a51843dd-77f5-462d-8206-8022e7db98eb","owner":[],"postedDate":"April 23rd, 2026","published":true,"recentEditorialEvents":[{"type":"editorInvitedReview","content":"","date":"2026-05-18T23:22:56+00:00","index":17,"fulltext":""},{"type":"reviewerAgreed","content":"208752840099839145154773711455692399400","date":"2026-05-13T11:18:36+00:00","index":16,"fulltext":""}],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[],"tags":[],"updatedAt":"2026-04-23T10:50:41+00:00","versionOfRecord":[],"versionCreatedAt":"2026-04-23 10:50:41","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-9139067","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-9139067","identity":"rs-9139067","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}