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MedLine Citation:
PMID:  22712522     Owner:  NLM     Status:  Publisher    
Cadaveric tendon allografts form a readily available and underutilized source of graft material. Because of their material properties, allografts are biomechanically and biologically superior to synthetic scaffolds. However, prior to clinical use, allografts must undergo decellularization to reduce immunogenicity and oxidation to increase porosity, leaving a nonvital biostatic scaffold. Ex vivo seeding, or "revitalization", is thought to hasten graft incorporation and stimulate intrinsic tendon healing, permitting early mobilization and return to function. In this study, we examined physical and biochemical augmentation methods including scaffold surface scoring (physical) and rehydration of lyophilized scaffolds in serum (biochemical). Scaffolds were divided into 4 groups: (1) scored scaffolds, (2) lyophilized scaffolds rehydrated in fetal calf serum, (3) scaffolds both scored and rehydrated in fetal calf serum and (4) control scaffolds. Scaffolds were reseeded with adipoderived stem cells (ADSC). Reseeding efficacy was quantified by live cell and total cell assays and qualified histologically with H&E, live/dead and SYTOgreen nucleic acid stains, TUNEL apoptosis stains, procollagen stains and transmission electron microscopy. Scaffold-seeded cell viability at up to 2 weeks in vitro and up to 4 weeks in vivo was demonstrated with bioluminescent imaging of scaffolds seeded with luciferase-positive ADSC. The effect of seeding on scaffold biomechanical properties was demonstrated with evaluation of ultimate tensile stress (UTS) and elastic modulus (EM). We found that scaffold surface scoring led to increase in live and total cell attachment and penetration (MTS assay, p<0.001 and DNA assay, p=0.003, respectively). Histology confirmed greater total cell number in both construct core and surface in scored compared with unscored constructs. Cells reseeded on scored constructs displayed reduced apoptosis, persistent procollagen production and had similar ultrastructural relationship to the surrounding matrix as native tenocytes on transmission electron microscopy. Rehydration of lyophilized scaffolds in serum did not improve reseeding. Seeded constructs demonstrated greater UTS and EM than unseeded constructs. Scaffolds seeded with ADSC-luc2-eGFP demonstrated persistent viability for at least 2 weeks in vitro. In conclusion, tendon surface scoring increases surface and core reseeding in vitro and may be incorporated as a final step in allograft processing prior to clinical implantation.
Colin Yl Woon; Simon Johann Farnebo; Taliah Schmitt; Kai Megerle; Hung Pham; Armin Kraus; Xinrui Yan; Sanjiv Gambhir
Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2012-6-19
Journal Detail:
Title:  Tissue engineering. Part A     Volume:  -     ISSN:  1937-335X     ISO Abbreviation:  -     Publication Date:  2012 Jun 
Date Detail:
Created Date:  2012-6-20     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  101466659     Medline TA:  Tissue Eng Part A     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
Stanford University Medical Center, Division of Plastic Surgery, Division of Plastic & Reconstructive Surgery, Stanford University Medical Center, 770 Welch Road, Suite 400, Palo Alto, California, United States, 94304, 650-723-5824;
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