{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,9,27]],"date-time":"2025-09-27T22:08:10Z","timestamp":1759010890736,"version":"3.41.2"},"reference-count":37,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2021,9,17]],"date-time":"2021-09-17T00:00:00Z","timestamp":1631836800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/100000062","name":"National Institute of Diabetes and Digestive and Kidney Diseases","doi-asserted-by":"publisher","id":[{"id":"10.13039\/100000062","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Bioeng. Biotechnol."],"abstract":"<jats:p>Ureteral reconstruction with autologous tissue grafts is often limited by tissue availability and donor site morbidity. This study investigates the performance of acellular, bi-layer silk fibroin (BLSF) scaffolds in a porcine model of ureteroplasty. Tubular ureteroplasty with BLSF grafts in combination with transient stenting for 8\u00a0weeks was performed in adult female, Yucatan, mini-swine (<jats:italic>N<\/jats:italic> = 5). Animals were maintained for 12\u00a0weeks post-op with imaging of neoconduits using ultrasonography and retrograde ureteropyelography carried out at 2 and 4\u00a0weeks intervals. End-point analyses of ureteral neotissues and unoperated controls included histological, immunohistochemical (IHC), histomorphometric evaluations as well as <jats:italic>ex vivo<\/jats:italic> functional assessments of contraction\/relaxation. All animals survived until scheduled euthanasia and displayed mild hydronephrosis (Grades 1-2) in reconstructed collecting systems during the 8\u00a0weeks stenting period with one animal presenting with a persistent subcutaneous fistula at 2\u00a0weeks post-op. By 12\u00a0weeks of scaffold implantation, unstented neoconduits led to severe hydronephrosis (Grade 4) and stricture formation in the interior of graft sites in 80% of swine. Bulk scaffold extrusion into the distal ureter was also apparent in 60% of swine contributing to ureteral obstruction. However, histological and IHC analyses revealed the formation of innervated, vascularized neotissues with <jats:italic>a<\/jats:italic>-smooth muscle actin+ and SM22\u03b1+ smooth muscle bundles as well as uroplakin 3A+ and pan-cytokeratin + urothelium. <jats:italic>Ex vivo<\/jats:italic> contractility and relaxation responses of neotissues were similar to unoperated control segments. BLSF biomaterials represent emerging platforms for tubular ureteroplasty, however further optimization is needed to improve <jats:italic>in vivo<\/jats:italic> degradation kinetics and mitigate stricture formation.<\/jats:p>","DOI":"10.3389\/fbioe.2021.723559","type":"journal-article","created":{"date-parts":[[2021,9,17]],"date-time":"2021-09-17T05:17:47Z","timestamp":1631855867000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":6,"title":["Evaluation of Bi-Layer Silk Fibroin Grafts for Tubular Ureteroplasty in a Porcine Defect Model"],"prefix":"10.3389","volume":"9","author":[{"given":"Gokhan","family":"Gundogdu","sequence":"first","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Zhamshid","family":"Okhunov","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Vivian","family":"Cristofaro","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Stephanie","family":"Starek","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Faith","family":"Veneri","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Hazem","family":"Orabi","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Pengbo","family":"Jiang","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Maryrose P.","family":"Sullivan","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Joshua R.","family":"Mauney","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1965","published-online":{"date-parts":[[2021,9,17]]},"reference":[{"key":"B1","doi-asserted-by":"publisher","first-page":"855","DOI":"10.1089\/ten.TEA.2018.0113","article-title":"Augmentation Cystoplasty of Diseased Porcine Bladders with Bi-layer Silk Fibroin Grafts","volume":"25","author":"Affas","year":"2019","journal-title":"Tissue Eng. 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