title: Long-term efficacy of a novel ribose-cross-linked collagen dermal filler: a histologic and histomorphometric study in an animal model.
abstract: BACKGROUND
  Degradation and loss of the three-dimensional shape are the major causes of limited functional longevity of dermal fillers made of natural polymers as collagen and hyaluronic acid.
  
  
  OBJECTIVE
  This study assessed the functional longevity of a new ribose-cross-linked collagen filler during 24 months in an animal model.
  
  
  METHODS
  Ribose-cross-linked collagen (Evolence, Colbar Life Sciences Ltd), glutaraldehyde-cross-linked collagen (Zyplast, Inamed Inc.), and non-cross-linked collagen (Zyderm, Inamed Inc.) were injected in the rabbit ear dermis. Biopsies obtained at 1, 6, 12, and 24 months were histomorphometrically assessed for shape preservation and cell repopulation.
  
  
  RESULTS
  The three-dimensional shape of Evolence remained stable during 24 months. Zyderm and Zyplast lost their three-dimensional shape after 6 months. Although the cell density in Evolence remained stable over time, that in Zyplast and Zyderm decreased significantly at 12 and 24 months.
  
  
  CONCLUSIONS
  Ribose-cross-linked collagen is endowed with a higher functional longevity as assessed in an animal model when compared with the most used collagen-based dermal fillers.
authors.affiliation: Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel. pitaru@post.tau.ac.il
authors.forename: Sandu
authors.initials: S
authors.lastname: Pitaru
authors.forename: Matitiau
authors.initials: M
authors.lastname: Noff
authors.forename: Liat
authors.initials: L
authors.lastname: Blok
authors.forename: Eran
authors.initials: E
authors.lastname: Nir
authors.forename: Shahar
authors.initials: S
authors.lastname: Pitaru
authors.forename: Arie
authors.initials: A
authors.lastname: Goldlust
authors.forename: Naftali
authors.initials: N
authors.lastname: Savion
mesh_terms: D000818:Animals; D002452:Cell Count; D003094:Collagen; D024042:Collagen Type I / Q000008:administration & dosage / Q000627:therapeutic use*; D003432:Cross-Linking Reagents; D005260:Female; D007271:Injections, Intradermal; D019736:Prostheses and Implants; D011817:Rabbits; D012266:Ribose; D013997:Time Factors
chemical_list: D024042:Collagen Type I; D003432:Cross-Linking Reagents; C048470:glutaraldehyde-cross-linked collagen; D012266:Ribose; D003094:Collagen