title: Assessment of essential characteristics of two different scaffolds for tendon in situ regeneration.
abstract: OBJECTIVE
  Rotator cuff tears are challenging as the rate of re-ruptures remains high. Thus, new therapeutic strategies need to be developed. Tendon in situ regeneration (TSR) attempts to produce cell-scaffold constructs in vitro, which can produce tendinous tissue of high quality after replantation. Therefore, it is essential to find suitable scaffolds that can provide acceptable biofunctionality and biocompatibility. This study compares characteristics of scaffolds for in situ regeneration: a polyglycolic acid/PDS scaffold (PP-sca) (Ethisorb, Ethicon, Germany) and a collagen sponge (col-spo) (TissueTek, Germany) with a basal strengthening membrane.
  
  
  METHODS
  Tendon-derived cells (TDCs) were isolated from the long head of the biceps tendon. Gene expression for collagen type I, collagen type III, decorin, scleraxis and tenomodulin was analysed in the third cell passage. Cell proliferation in cell seeded scaffolds was tested using a WST-1 assay. In addition, the tensile strength of both scaffolds was measured using a universal-testing machine (Zwick/Roell, Ulm, Germany).
  
  
  RESULTS
  The results from this study indicate a genotypic drift during the in vitro cultivation of the TDCs. The PP-sca showed good biofunctional results, including low initial loss of cells after cell seeding. The proliferation rates were approximately equal in each type of scaffold. The col-spo provided superior tensile strength compared with the PP-sca (p < 0.01).
  
  
  CONCLUSIONS
  Overall, the col-spo seems to be more suitable for TSR. It may become a clinical alternative in the future to achieve more satisfying results, concerning function and pain.
  
  
  METHODS
  Experimental study/case series, Level IV.
authors.affiliation: Department of Vascular and Endovascular Surgery, Heinrich-Heine University Düsseldorf, Moorenstraße 5, 40225, Düsseldorf, Germany, markus.wagenhaeuser@freenet.de.
authors.forename: Markus U
authors.initials: MU
authors.lastname: Wagenhäuser
authors.forename: Matthias F
authors.initials: MF
authors.lastname: Pietschmann
authors.forename: Denitsa
authors.initials: D
authors.lastname: Docheva
authors.forename: Mehmet F
authors.initials: MF
authors.lastname: Gülecyüz
authors.forename: Volkmar
authors.initials: V
authors.lastname: Jansson
authors.forename: Peter E
authors.initials: PE
authors.lastname: Müller
mesh_terms: D018929:Cell Culture Techniques; D049109:Cell Proliferation; D003094:Collagen / Q000096:biosynthesis / Q000235:genetics*; D004247:DNA / Q000235:genetics*; D005786:Gene Expression Regulation; D006801:Humans; D012038:Regeneration; D013710:Tendons / Q000166:cytology / Q000378:metabolism*; D013718:Tensile Strength; D054457:Tissue Scaffolds / Q000737:chemistry*
chemical_list: D003094:Collagen; D004247:DNA