title: A novel in vivo model for evaluating functional restoration of a tissue-engineered salivary gland.
abstract: OBJECTIVE
  To create a novel model for development of a tissue-engineered salivary gland from human salivary gland cells that retains progenitor cell markers useful for treatment of radiation-induced xerostomia.
  
  
  METHODS
  A three-dimensional (3D) hyaluronic acid (HA)-based hydrogel scaffold was used to encapsulate primary human salivary gland cells and to obtain organized acini-like spheroids. Hydrogels were implanted into rat models, and cell viability and receptor expression were evaluated.
  
  
  METHODS
  A parotid gland surgical resection model for xenografting was developed. Salivary cells loaded in HA hydrogels formed spheroids and in vitro were implanted in the three-fourths resected parotid bed of athymic rats. Implants were removed after 1 week and analyzed for spheroid viability and phenotype retention.
  
  
  RESULTS
  Spheroids in 3D stained positive for HA receptors CD168/RHAMM and CD44, which is also a progenitor cell marker. The parotid gland three-fourths resection model was well-tolerated by rodent hosts, and the salivary cell/hydrogel scaffolds were adherent to the remaining parotid gland, with no obvious signs of inflammation. A majority of human cells in the extracted hydrogels demonstrated robust expression of CD44.
  
  
  CONCLUSIONS
  A 3D HA-based hydrogel scaffold that supported long-term culture of salivary gland cells into organized spheroids was established. An in vivo salivary gland resection model was developed that allowed for integration of the 3D HA hydrogel scaffold with the existing glandular parenchyma. The expression of CD44 among salivary cultures may partially explain their regenerative potential, and the expression of CD168/RHAMM along with CD44 may aid the development of these 3D spheroids into regenerated salivary glands.
  
  
  METHODS
  NA.
authors.affiliation: Department of Biological Sciences, Biomedical Engineering Program, University of Delaware, Newark, Delaware; Department of Materials Sciences and Engineering, Biomedical Engineering Program , University of Delaware, Newark, Delaware; Department of Otolaryngology-Head and Neck Surgery, Thomas Jefferson University, Philadelphia, Pennsylvania, U.S.A.
authors.forename: Swati
authors.initials: S
authors.lastname: Pradhan-Bhatt
authors.forename: Daniel A
authors.initials: DA
authors.lastname: Harrington
authors.forename: Randall L
authors.initials: RL
authors.lastname: Duncan
authors.forename: Mary C
authors.initials: MC
authors.lastname: Farach-Carson
authors.forename: Xinqiao
authors.initials: X
authors.lastname: Jia
authors.forename: Robert L
authors.initials: RL
authors.lastname: Witt
mesh_terms: D000328:Adult; D000818:Animals; D006801:Humans; D020100:Hydrogels; D008297:Male; D008875:Middle Aged; D051381:Rats; D017207:Rats, Sprague-Dawley; D020127:Recovery of Function; D012469:Salivary Glands / Q000502:physiology / Q000601:surgery*; D023822:Tissue Engineering / Q000379:methods
chemical_list: D020100:Hydrogels
keywords: Bioartificial organ; hyaluronic acid receptors; hyaluronic acid-based hydrogels; progenitor cells; regeneration; salivary gland; three-dimensional cell culture; tissue engineering