title: Glycol chitin-based thermoresponsive hydrogel scaffold supplemented with enamel matrix derivative promotes odontogenic differentiation of human dental pulp cells.
abstract: BACKGROUND
  Hydrogels have been widely studied as tissue engineering scaffolds over the past 2 decades because of their favorable biological properties. Recently, a new biodegradable glycol chitin-based thermoresponsive hydrogel scaffold (GC-TRS) was developed that can be easily applied as a mild viscous solution at room temperature but quickly transforms into a durable hydrogel under physiological conditions. The aim of this study was to investigate the effects of GC-TRS on the proliferation and odontogenic differentiation of colony-forming human dental pulp cells (hDPCs) in the presence of enamel matrix derivative.
  
  
  METHODS
  Glycol chitin was synthesized by N-acetylation of glycol chitosan. The morphology of the thermoresponsive hydrogel scaffold was observed by using scanning electron microscopy. The sol gel phase transition of the aqueous solution of glycol chitin was investigated by using the tilting method and rheometer studies. hDPCs were isolated based on their ability to generate clonogenic adherent cell clusters. The effect of GC-TRS and collagen on cell viability was examined by performing 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Expression of markers for odontogenic/osteogenic differentiation (ie, dentin sialophosphoprotein, dentin matrix protein-1, osteonectin, and osteopontin) was analyzed by performing real-time polymerase chain reaction.
  
  
  RESULTS
  GC-TRS exhibited a highly macroporous and well-interconnected porous structure. The polymer solution existed in a mildly viscous sol state, but it transitioned to a gel state and did not flow above approximately 37°C. Rheometer studies showed that the glycol chitin solution exhibited a fast sol gel transition approximately at body temperature. GC-TRS and collagen did not inhibit cell viability until 7 days. Dentin sialophosphoprotein and dentin matrix protein-1 were expressed by cells cultured in GC-TRS at a higher level than that in cells cultured in collagen (P < .05). In both the scaffold groups, dentin sialophosphoprotein, dentin matrix protein-1, and osteopontin messenger RNA was up-regulated significantly in EMD-treated hDPCs when compared with the nontreated cells (P < .05).
  
  
  CONCLUSIONS
  GC-TRS allowed the proliferation and odontogenic differentiation of hDPCs. Furthermore, the differentiation was facilitated by EMD. These results suggest that GC-TRS has the potential to be used in tissue engineering techniques for dentin regeneration.
authors.affiliation: Department of Conservative Dentistry, Wonkwang University School of Dentistry, Iksan, Korea.
authors.forename: Su-Jung
authors.initials: SJ
authors.lastname: Park
authors.forename: Zhengzheng
authors.initials: Z
authors.lastname: Li
authors.forename: In-Nam
authors.initials: IN
authors.lastname: Hwang
authors.forename: Kang Moo
authors.initials: KM
authors.lastname: Huh
authors.forename: Kyung-San
authors.initials: KS
authors.lastname: Min
mesh_terms: D001831:Body Temperature / Q000502:physiology; D018929:Cell Culture Techniques; D002454:Cell Differentiation / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D002686:Chitin / Q000031:analogs & derivatives* / Q000737:chemistry; D003094:Collagen / Q000494:pharmacology; D004396:Coloring Agents; D003746:Dental Enamel Proteins / Q000627:therapeutic use*; D003782:Dental Pulp / Q000166:cytology* / Q000187:drug effects; D016326:Extracellular Matrix Proteins / Q000032:analysis; D006801:Humans; D020100:Hydrogels / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D009805:Odontogenesis / Q000187:drug effects*; D015676:Osteonectin / Q000032:analysis; D053495:Osteopontin / Q000032:analysis; D044367:Phase Transition; D010750:Phosphoproteins / Q000032:analysis; D016062:Porosity; D012212:Rheology; D012795:Sialoglycoproteins / Q000032:analysis; D013234:Stem Cells / Q000187:drug effects* / Q000502:physiology; D013778:Tetrazolium Salts; D013844:Thiazoles; D023822:Tissue Engineering / Q000379:methods; D054457:Tissue Scaffolds / Q000737:chemistry*; D000099311:Dentin Sialophosphoprotein
chemical_list: D002686:Chitin; D003094:Collagen; D004396:Coloring Agents; D003746:Dental Enamel Proteins; D016326:Extracellular Matrix Proteins; D020100:Hydrogels; D015676:Osteonectin; D053495:Osteopontin; D010750:Phosphoproteins; D012795:Sialoglycoproteins; D013778:Tetrazolium Salts; D013844:Thiazoles; D000099311:Dentin Sialophosphoprotein; C513309:DMP1 protein, human; C109069:enamel matrix proteins; C031610:glycolchitin; C022616:thiazolyl blue
keywords: Enamel matrix derivative; glycol chitin; human dental pulp cell; hydrogel; odontogenic differentiation; thermoresponsive