title: RNA isolation from alveolar bone and gene expression analysis of RANK, RANKL and OPG: A new tool to monitor bone remodeling and healing in different bone substitutes used for prosthetic rehabilitation.
abstract: OBJECTIVE
  (i) To validate a simple and efficient method for extracting high quality RNA from small samples of bone tissue, (ii) to test its application on limited amounts of grafted oral bone and (iii) to analyze the gene expression of the OPG/RANK/RANKL system and IL-6 in "spontaneous healing" and grafted tissue.
  
  
  METHODS
  26 patients in need of extraction of one lower molar tooth were divided in 3 groups. In group A (8 patients) the alveolar socket was left for spontaneous healing, in group B (8 patients) it was filled with a hydroxyapatite scaffold while in group C (10 patients) it was filled with hydroxyapatite granules. A small amount of bone was scraped from the alveolar site and sent for analysis. Four months later a new bone specimen was harvested during implant bed preparation.
  
  
  RESULTS
  IL-6 increased over time in all groups and in particular to the grafted groups. RANK, RANKL and OPG increased over time in all groups, except for RANK in group B. The RANKL/OPG ratio showed a negative value in group A and even more in group B, while it was positive in group C.
  
  
  CONCLUSIONS
  The alveolar site grafted with a granular biomaterial behaved similar to the physiological healing group but displayed a slow remodeling process. RANK, RANKL, OPG and the RANKL/OPG ratio might be able to distinguish among different biomaterials and represent different healing patterns according to different clinical conditions.
authors.affiliation: Dipartimento di Scienze Biomediche, Chirurgiche ed Odontoiatriche, Università degli Studi di Milano, Milano, Italy.
authors.forename: Elena
authors.initials: E
authors.lastname: Canciani
authors.affiliation: Dipartimento di Scienze Biomediche, Chirurgiche ed Odontoiatriche, Università degli Studi di Milano, Milano, Italy.
authors.forename: Claudia
authors.initials: C
authors.lastname: Dellavia
authors.affiliation: Dipartimento di Scienze Biomediche per la Salute, Università degli Studi di Milano, Milano, Italy.
authors.forename: Monica Gioia
authors.initials: MG
authors.lastname: Marazzi
authors.affiliation: Private Practice, Milano, Italy.
authors.forename: Davide
authors.initials: D
authors.lastname: Augusti
authors.affiliation: Dipartimento di Scienze Biomediche, Chirurgiche ed Odontoiatriche, Università degli Studi di Milano, Milano, Italy. Electronic address: daniela.carmagnola@gmail.com.
authors.forename: Daniela
authors.initials: D
authors.lastname: Carmagnola
authors.affiliation: Dipartimento di Scienze Biomediche per la Salute, Università degli Studi di Milano, Milano, Italy.
authors.forename: Elena
authors.initials: E
authors.lastname: Vianello
authors.affiliation: Private Practice, Rome, Italy.
authors.forename: Luigi
authors.initials: L
authors.lastname: Canullo
authors.affiliation: Dipartimento di Scienze Biomediche, Chirurgiche ed Odontoiatriche, Università degli Studi di Milano, Milano, Italy; Dipartimento di Scienze Biomediche per la Salute, Università degli Studi di Milano, Milano, Italy.
authors.forename: Emanuela
authors.initials: E
authors.lastname: Galliera
mesh_terms: D000539:Alveolar Process / Q000378:metabolism* / Q000601:surgery*; D001672:Biocompatible Materials / Q000494:pharmacology; D016723:Bone Remodeling / Q000502:physiology*; D018786:Bone Substitutes / Q000494:pharmacology*; D017886:Durapatite / Q000494:pharmacology; D015870:Gene Expression; D006801:Humans; D015850:Interleukin-6 / Q000378:metabolism; D008422:Materials Testing; D053244:Osteoprotegerin / Q000378:metabolism*; D053245:RANK Ligand / Q000378:metabolism*; D012313:RNA / Q000302:isolation & purification*; D060888:Real-Time Polymerase Chain Reaction; D053246:Receptor Activator of Nuclear Factor-kappa B / Q000378:metabolism*; D014081:Tooth Extraction; D020390:Tooth Socket / Q000187:drug effects; D016896:Treatment Outcome; D014945:Wound Healing / Q000502:physiology*
chemical_list: D001672:Biocompatible Materials; D018786:Bone Substitutes; D015850:Interleukin-6; D053244:Osteoprotegerin; D053245:RANK Ligand; D053246:Receptor Activator of Nuclear Factor-kappa B; D012313:RNA; D017886:Durapatite
keywords: Alveolar bone; Bone remodeling; Osteoimmunological markers; RNA isolation; Real time PCR