Autologous Alveolar Bone Marrow Mesenchymal Stem Cells for the Reconstruction of Infrabony Periodontal Defects
Condition: Chronic Periodontitis
MeSH terms: Periodontitis; Chronic Periodontitis
Study type: Interventional
Phase: Phase 1/Phase 2

Summary: 
      Systemically healthy periodontitis patients are recruited from new referrals to the
      Department of Periodontology and Biology of Implants, AUTh. After completion of non-surgical
      periodontal treatment those subjects who have at least one interdental osseous defect with
      probing pocket depth and clinical attachment level of ≥ 6mm and an intrabony component of ≥
      3mm with no endodontic or furcation involvement are randomly allocated into one of the three
      treatment groups. Group A receives regenerative treatment using autologous bone marrow
      mesenchymal stem cells free of animal derived reagents, produced in clean room facilities and
      seeded into collagen scaffolds enriched with fibrin glue; in Group B, a collagen fleece
      enriched with fibrin glue devoid of stem cells fills the osseous defect; Group C receives
      open flap debridement retaining the soft wall of the defect. Thereafter, subjects are
      followed for 12 months and are repeatedly assessed based on clinical, radiographic,
      immunological and microbiological parameters.

      In a series of cases, tissue engineering in a similar manner to Group A will be applied to
      treat isolated periodontal interdental defects, in combination with the novel "closed
      surgical technique".
    

Detailed description: 
      Aims & Objectives The present study describes a novel method to regenerate periodontal
      tissues in periodontal infrabony defects using autologous BM-MSCs, free of animal derived
      reagents, produced in clean room facilities enriched with autologous fibrin glue and seeded
      into commercially available collagen scaffolds (collagen fleece).

      Primary objective This study aims to assess the efficacy of a novel regenerative treatment of
      periodontal infrabony defects using a biocomplex of BM-MSCs/fibrin glue/collagen fleece, as
      compared to a cell-free grafting substitute of fibrin glue/collagen fleece and to a control
      treatment approach of open flap debridement with no adjunctive use of grafting materials.

      Secondary Objectives

        -  To document the stability of the enhanced treatment outcome and to continue to assess
           the safety and effectiveness of BM-MSCs transplantation as compared to the control
           treatment of open flap debridement over the study period.

        -  Determine the immunological and microbiological profiles of the participants throughout
           the study period in an attempt to understand local and systemic effects of the
           transplantation of BM-MSCs in chronically diseased sites, such as the infrabony
           periodontal defect. In addition, the healing response to treatment will be determined
           throughout the observation period (baseline to 12-months).

      Study Design

      Investigational products aBM-MSCs cultures will be established from osseous biopsies derived
      from bone marrow of the alveolar bone in each patient belonging to Group A. Briefly, after a
      thorough oral rinse with chlorhexidine 0.12% for 1min, an osteotomy using a trephine drill
      will be performed in the alveolar bone and a 2x8 mm osseous core will be harvested. The area
      will be irrigated with saline solution and then flaps will be sutured to achieve primary
      closure at the donor site. The bone sample will be then immediately placed in sterile tubes
      containing HBSS and antibiotics/antimycotics and will be transported to a Good Laboratory
      Practice (GLP)-compliant authorized facility meeting the quality guidelines set by the
      European Union for the preparation of clinical-grade stem cell cultures for delivery to the
      patient. aBM-MSC isolation will be performed using the enzymatic dissociation method, as
      previously described (Bakopoulou 2013). For culture expansion, autologous serum obtained from
      60ml of venous blood collected from each subject will be used to supplement aMEM cell culture
      medium, in order to avoid the use of any animal derived reagents, such as bovine serum. The
      osseous biopsy will be immediately processed to ensure high viability of the established
      cultures. After expansion for two passages (approximate time needed 16-24 days depending on
      cell donor) cells will be harvested for delivery to the patient. For cell dissociation and
      passaging, highly purified, GMP compatible recombinant enzymes (Tryple, Thermo Fisher
      Scientific) will be used to avoid use of porcine trypsin. At this stage, a sample of 20ml
      venous blood will be required for the preparation of the autologous fibrin glue in Group B,
      as in Group A initial bloodletting (60ml) will cover the needs of the cell cultures and
      fibrin glue preparation. Subsequently, fibrin glue will be loaded with- (Group A) or without-
      (Group B) stem cells into a commercially available collagen fleece scaffold directly before
      clinical application.

      Quality control of the established BM-MSC cultures before clinical application

      Before delivery to the patient, all BM-MSCs cultures will be evaluated for:

        -  Viability using Trypan Blue exclusion

        -  Sterility: cultures will be tested for potential contamination from bacteria, mycoplasma
           and endotoxins (LAL test)

        -  "Stemness" properties based on the minimal criteria established by the International
           Society for Cellular Therapy (ISCT) regarding MSCs (Dominici et al 2006).

      Note: Methodology on stem cell characterization methods is analytically described in previous
      publications by our research group (Bakopoulou et al. 2013).

      After application of the BM-MSCs/fibrin glue/CaCl2 mixture into the collagen scaffolds, a
      small sample of the biocomplex of randomly selected cases will be separated using surgical
      scissors and will be transferred to the lab for further (in parallel to the clinical
      application) ex vivo characterization of stem cell behavior in a biomimetic microenvironment.
      This will allow correlation between stem cell behavior and the clinical outcome, since
      retrieval and analysis of the regenerated tissues directly from the host is not feasible for
      ethical reasons.

      Preparation of autologous fibrin glue Twenty ml of venous blood will be collected from the
      ante-cubital fossa of patients in Groups A and B and blood samples will be immediately
      transferred to a falcon tube, which contains anticoagulant. After determination of the
      platelet counts the blood sample will be centrifuged (2000rpm, 10min) and plasma will be
      separated and stored in another falcon. Platelets counts will be then determined and the
      sample will be centrifuged again. PRP (platelet rich plasma containing 1,000,000 plts/ul)
      will be then separated from the supernatant PPP (platelet poor plasma) and both preparations
      will be further processed following a standard protocol for fibrin glue preparation
      (Biohellenika, Thessaloniki, Greece).

      Design of the clinical arm of the study

      Pre-selection of Subjects Subjects will be recruited from new referrals at the Department of
      Preventive Dentistry, Periodontology and Implant Biology; no external advertising or
      recruitment will be undertaken. Subjects will be in good general health.

      Admission into the Study Before admission into the study, each subject will be informed by
      the principal investigator of the nature and risks of the study both orally and in writing
      (Subject Information Form) and written informed consent (Subject Informed Consent Signature
      Form) will be obtained. Each subject will be given a copy of their duly signed consent form
      to maintain for their own records. The subjects' personal demographics and medical history
      and study suitability in accordance with the inclusion and exclusion criteria set in the
      protocol will be recorded. Subjects may continue any medications not included in the
      exclusion criteria; however, these medications should be documented together with any
      concurrent medical condition not pre-excluded.

      Procedures for Subject Withdrawal or Discontinuation Any subject, who wishes to withdraw from
      the study for personal or any other reason, is entitled to do so. However, the reason for the
      withdrawal of any subject from the study in addition to whether the reason is related to the
      test product will be recorded by the principal investigator. Any participant failing to
      attend more than twice is removed from the study. Subjects that experience an adverse event
      will be excluded from further participation in the study.

      If a subject wishes to withdraw from the study, all efforts will be made to complete and
      report the observations as thoroughly as possible up to the date of withdrawal. Subjects will
      be asked to consider giving further information as to the reason(s) for the withdrawal. Any
      information reported will be recorded.

      Expected Duration of each subject participation Each subject is expected to attend nine
      visits in total over a period of 12 months; one screening visit, one treatment visit to
      receive surgical treatment of the designated area, four follow-up reviews and three
      additional visits for clinical and radiographic reassessment and sample collection (whole
      saliva, gingival crevicular fluid (GCF), subgingival plaque).

      Investigators' calibration and randomisation Patients will be screened for eligibility by one
      examiner and will be enrolled one at a time on a continuous basis after obtaining a code
      number. A trial contributor not involved in data collection will perform the randomisation
      and announce the treatment modality to the therapist using telephone communication. Clinical
      assessments will be carried out by a single examiner who will have no access to previous
      recordings and is not otherwise involved in other clinical procedures. An investigator
      calibration exercise will be performed to obtain acceptable intra-examiner reproducibility
      for PPD, CAL, and evaluation of defect anatomy. Intra-examiner reproducibility will be
      evaluated by Intraclass Correlation Coefficient (ICC) and Bland-Altman 95% limits of
      agreement (Bland and Altman, 1999).

      Statistical analysis of experimental data The analysis will be performed using the IBM
      Statistics SPSS 20.0, software. Data will be expressed as means +/- standard deviation (SD).
      Unbalances between the test and control groups that are generated by the randomisation
      procedures will be assessed using the independent samples t-test for continuous variables and
      the Fisher's Exact test or the Chi-Square test for categorical variables. The significance of
      the treatment effects on the dependent variables CAL changes, PPD changes and radiographic
      changes will be estimated by constructing linear mixed models using the SPSS MIXED procedure.
      For all analyses the statistical significance will be set at p<0.05.

      Ethical considerations / Authorisations for stem cell cultures Biohellenika, Thessaloniki,
      Greece provides state of the art facilities and labs that are operating under the strictest
      regulations for stem cells processing and storage. The labs are licensed according to
      Government's order 26/24-3-2008 (regulation of Greek law according to European law 2004/23/K
      of and Council 31-3-2004 for the establishment prototypes of quality and safety for the
      donation, the purchase, the quality controls the cryopreservation, storage and the
      distribution of human tissues and cells (EEL 102/7-4-2004) and the related guidelines 2006/17
      EK (EEL 38/9/2006) and 2006/86EK (EEL 294/25-10-2006). The license F 6172/17514/1269 is
      published in Gov. paper 2589 31/12/2009.

      Since November 2014, Biohellenika operates under the new law 3984, published in Gov paper No
      150, 2011 after a positive recommendation of the National Transplant Committee to Department
      of Health and at the moment the new license is about to published in the Gov paper.

      The labs and the procedures are accredited by the American Association of Blood Banks (AABB),
      last inspection 30th of September, 2014 and by the National System of Accreditation according
      to ISO 15189:2007. Also the labs are certified according to ISO 9001:2008, for processing,
      quality control and cryopreservation of autologous cell lineages and ISO 13485:2003 for the
      cryopreservation system which is also an international patent of Biohellenika.

      Clean rooms operate according to the guidelines of BSR Ingenieur-Buro with ISO 14644-5. The
      security levels meet all the standards ISO 27001 and the company is licensed and regulated by
      the Data Protection Authority.

      The labs are surveyed 24 hours for air quality and equipped with Cryo-View data base System,
      ISBT 128 barcoding system, Temperature -Liquid N2 level, Security Alarms and two power
      generators.

      Study Schedule Clinical design and interventions for autologous transplantation of BM-MSCs
      Subjects with severe chronic periodontitis will be scheduled to receive non-surgical
      periodontal treatment under local anaesthesia using hand and power driven instruments, in
      addition to motivation in periodontal care and thorough oral hygiene instructions. Subjects
      will be clinically reassessed six weeks after the completion of non-surgical treatment and
      those subjects with remaining periodontal pockets (PPD & CAL ≥ 6mm; infrabony component ≥
      3mm) and no overt signs of gingival inflammation will be screened for suitability to
      participate in the current study. The screening visit will include an initial full-mouth
      periodontal examination, intra-oral radiographic examination and fulfilment of
      inclusion/exclusion criteria. In case of suitability, the nature of the study will be
      explained in detail to all subjects and a signed consent form approved by the Ethics
      Committee of the Dental School, AUTh. will be obtained from each participant. Then, patients
      will be randomly allocated into one of the three treatment Groups (-A, -B and -C). A single
      defect will be treated in each patient.

      Subsequently, an osseous biopsy and blood samples will be collected from the participants of
      Group A under strict sterile conditions. Each sample will be then immediately placed in
      sterile tubes and will be transported to Biohellenika, Thessaloniki, Greece
      (http://www.biohellenika.gr) for stem cell isolation and expansion according to a strict
      protocol (Bakopoulou et al. 2013, Bakopoulou et al. in preparation). Since MSCs will be
      isolated and expanded in vitro in GLP-class clean rooms meeting the quality guidelines set by
      the European Union and no animal derived reagents will be used throughout the experiments for
      autologous transplantation, the cells are considered safe for human clinical cell therapy
      applications. In Biohellenika facilities 60ml of venous blood will be collected from each
      subject in Group A shortly after the biopsy harvest, so that autologous serum is used for the
      isolation and culture expansion of the autologous stem cells. In addition, autologous fibrin
      glue will be used to load the BM-MSCs onto the collagen fleece. In addition, a blood sample
      of 20ml will be collected from subjects in Group B, in order to provide fibrin glue which
      will enrich the collagen fleece before surgical placement into the osseous defect. Finally,
      subjects in Group C will not be called for bloodletting as the infrabony defects in these
      individuals will be surgically managed by open flap debridement with no adjunctive use of
      grafting materials.

      As part of the GLP quality control, the MSCs will be analysed for sterility and endotoxins
      and will be also tested for potential contamination from bacteria (BD BACTEC™), mycoplasma
      and endotoxins (LAL test).

      Local anaesthesia (1.8ml of 2% lidocaine with 1:80,000 epinephrine; Lignospan special,
      Septodont) will be infiltrated in the buccal and lingual aspects of the involved teeth
      avoiding the papillae. Then, strictly intra-sulcular incisions will be performed to preserve
      the gingival tissues and in particular the interdental papilla associated with the
      bone-dental defect (Cortellini, 2012; Cortellini and Tonetti 2007). The defect will be
      debrided and the root will be carefully planed with the combined use of Gracey curettes and
      power-driven instruments (EMS Piezon®, EMS, Nyon, Switzerland). Care will be taken to retain
      the soft-tissue wall of the defects and the osseous defect will be irrigated with saline to
      control bleeding.

      In Group A, the grafting material (BM-MSCs enriched with fibrin glue) will be delivered in
      two insulin syringes each containing 5x10E6 cells/100μl fibrin and will be gently loaded onto
      the collagen fleece and polymerized with the addition of CaCl2. Subsequently, the biocomplex
      will be gently packed into the defect until complete fill. Handling of the scaffold is done
      with care to avoid any destruction of viable cells.

      In Group B, the collagen fleece enriched with fibrin glue devoid of viable cells will fill
      the vertical bone defect with caution. In Groups -A and -B the delivery of fibrin glue
      with/without viable cells will be identical, so that the therapist is blinded to the
      procedures.

      Group C, patients will receive open flap debridement and root planing of the root surface in
      a similar manner as subjects in Groups -A and -B, but there will be no adjunctive use of
      grafting materials.

      The operator will be blinded to the treatment modality (Groups -A and -B), while in Group C
      since no grafting materials will be used, the treatment modality will become obvious to the
      operator but this will take place towards the conclusion of the surgery, after the collection
      of clinical data. Papilla preservation techniques and minimally invasive surgical techniques
      will be sought in all groups, avoiding scoring the periosteum. Flaps will be repositioned and
      sutured using a single modified internal mattress suture (5-0 Monosyn, Braun) at the
      defect-associated interdental area and similar sutures will be employed to close the flaps in
      any other interdental areas. Two weeks post-surgery clinical observation for uneventful
      healing or presence of adverse tissue reaction will be performed followed by suture removal.

      Case series for tissue engineering In a series of cases (five) having similar
      inclusion/criteria as above but without going through randomisation tissue engineering is
      applied following the same methodology as in Group A. In theses cases, the tissue engineered
      construct (biocomplex) is applied to treat isolated interdental periodontal defects using a
      newly designed surgical technique the so-called "closed surgical technique". In brief, this
      technique entails retraction of gingival flaps in a closed manner without dissecting the
      soft-tissues or the interdental papilla. This technique minimises tissue trauma,
      postoperative discomfort and enhances soft-tissue aesthetics.

      Post-operative care Post-operative pain will be controlled with Ibuprofen (600mg) at the end
      of the surgical procedure and 12h later if in pain. Amoxicillin (500mg / 8 hours for five
      days) will be prescribed to all participants. All patients will be instructed to use 0.12%
      chlorhexidine twice daily and avoid brushing, flossing and chewing hard in the treated area
      for four weeks. During this 4-week period, stringent post-operative supportive program care
      will be instituted at bi-weekly intervals, and after that patients will discontinue rinsing
      with chlorhexidine solution and resume oral hygiene. Interdental cleaning will commence six
      weeks post-surgery for all Groups. Thereafter, subjects will be seen at three, six and 12
      months for periodontal supportive care.

      Clinical recordings Full-mouth and site-specific periodontal recordings including BOP; Plaque
      Index (presence/absence of plaque); PPD and CAL will be determined using a manual periodontal
      probe (Hu-Friedy XP-23/QW) to the nearest millimetre at six sites per tooth and parallel to
      the long axis at four time-points; baseline, 6-, 9-, 12-months. Clinical measurements at the
      designated sites (infrabony defects) will be determined prior to surgery and before
      anaesthesia (baseline). Intra-surgical assessments will be carried out once during surgery.

      Intra-surgical clinical assessments The defect morphology (one-, two-, three-walls or
      combination) will be determined intra-surgically by the number of bone walls associated with
      the lesion; The distance between the cemento-enamel junction and the bottom of the defect
      (CEJ-BD) will be determined in mm; The distance from the CEJ to the most coronal
      interproximal level of the bone crest (CEJ-BC) will be determined in mm; The total defect
      depth: the distance between the bone crest and the bottom of the defect (BC-BD) will be
      determined in mm; The width of the defect width (horizontal distance between the bone crest
      and the root surface) will be determined in mm.

      If the CEJ is not detectable due to a cervical restoration the restoration margin (RM) will
      serve as reference point for clinical and radiographic measurements.

      Radiographic evaluation Intraoral digital radiography will be utilised to determine the bone
      regeneration of the infrabony defects at six time points; baseline, 6-weeks, 3-, 6-, 9-,
      12-months. Standardised periapical digital radiographs (RadioVisioGraphy; Trophy Radiology
      S.A., Paris, France) will be obtained using the long-cone paralleling technique. To
      standardise the exposure geometry, a customised bite-block of an elastic impression material
      will be adjusted on the sensor holder, stored in sealed plastic containers at room
      temperature and will be reused during every recall radiographic appointment.

      In a similar manner as the intra-surgical assessment, the following anatomical landmarks will
      be defined on the x-rays: the cementoenamel junction (CEJ), the most coronal level of the
      alveolar bone (BC) and the apical extent of bone loss (BD). In more detail, the location of
      the CEJ will be identified; the most coronal area where the periodontal ligament retains an
      even width will be identified on the radiograph to indicate the most apical extension of bone
      loss. The infrabony defect will be calculated by measuring the width of the defect at the
      most coronal aspect and at the base; the distance between CEJ-BD and BC-BD; the distance
      between CEJ-BC; the angle between the vertical axis of the root and the interdental bone wall
      (Tonetti et al. 1993). Radiographic evaluation of bone regeneration will be defined on a high
      definition monitor by the same calibrated examiner who is blinded to the treatment modality
      and does not have access to previous recordings. Assessments will be carried out using the
      measurement tool for numerical measurements (VixWin™ Platinum|Gendex software) with reference
      to a metal bar of standard length (5mm) that will be attached onto the sensor.

      Collection of specimens Samples will be collected in the following order at six time points;
      baseline, 6-weeks, 3-, 6-, 9-, 12-months.

      (i) Saliva Saliva will be collected prior to clinical periodontal measurements or any
      periodontal intervention and generally in the morning following an overnight fast during
      which subjects are requested not to drink (except water) or chew gum. Whole saliva samples
      will be obtained by expectorating into 30ml polypropylene tubes for 5 minutes.

      (ii) GCF Gingival crevicular fluid samples will be obtained from the buccal interdental
      aspects of the defects. Before GCF collection, the surfaces will be gently air dried and
      isolated from saliva by placing cotton rolls and using a saliva ejector. Then, supragingival
      plaque will be carefully removed with sterile curettes and paper strips (Periopaper, OraFlow
      Inc., Smithtown, NY, USA) will be placed in the periodontal pocket until mild resistance is
      felt for 30s. Care will be taken to avoid mechanical trauma when placing the strips and those
      strips contaminated with blood will be discarded. Each strip per patient will be stored in a
      separate 1.5ml micro-centrifuge tube, and stored at -70°C. Prior to use, the proteins on the
      strips will be eluted into 500µl of phosphate buffered saline (PBS) supplemented with BSA (1%
      v/v).

      (iii) Plaque Following GCF collection, subgingival plaque will be collected from the
      designated site. The sampling area will be isolated from saliva, gently dried with air, and
      after ensuring that no supragingival plaque deposits are present two paper points will be
      placed for 30s into the periodontal pocket and a pooled sample will be collected. All samples
      will be stored in Eppendorf tubes (Eppendorf, Hamburg, Germany) at -80°C before processing.
      Paper points will be used for the collection of microbial plaque in order to avoid mechanical
      disturbance of the periodontal tissues.

      Data management The investigators must ensure that the subject's anonymity is maintained. On
      any study-related documentation, subjects should only be identifiable by their initials,
      gender, and/or subject number. Personal information (i.e. medical cards) will be kept in a
      separate, secure location, away from other study specific data with restricted access to the
      principal investigator only.

      Informed consent process It is the responsibility of the principal investigator to obtain in
      writing consent from the subject. The informed consent form will consist of two separate
      documents; a Subject Information Form and a Subject Informed Consent Signature Form; both
      documents will be approved by the Ethical committee of the Dental School, AUTh prior to the
      study. The subject information form will provide an adequate explanation, in native
      non-technical language that is understandable to the subject, of the aims, objectives,
      methods, anticipated benefits and potential hazards of the study. The principal investigator
      must then provide ample time for the subject to read and understand the informed consent form
      and to consider participation in the clinical investigation. The principal investigator and
      the subject must both sign and date the form before the subject can participate in the
      clinical investigation. Each subject will then be issued with a copy of their duly signed and
      dated informed consent form and any other written information.
    

Intervention name(s): BM-MSCs/fibrin glue/collagen fleece; Fibrin glue/collagen fleece; Open flap debridement
Intervention type(s): Biological; Other; Procedure
Intervention description(s): Xeno-free, clinical-grade, autologous alveolar bone marrow mesenchymal stem cells enriched with autologous fibrin glue and loaded into a commercially available collagen fleece.; The biocomplex of autologous fibrin glue and collagen fleece devoid of stem cells will fill the osseous defect; Group C will receive minimally invasive surgery employing papilla preservation techniques in addition to retaining the soft tissue wall of the pocket. There will be no use of grafting materials
Other intervention name(s): Procedure/Surgery/Growth factors
Intervention MeSH terms: Fibrin Tissue Adhesive
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
Primary purpose: Treatment
Keywords: regeneration; stem cells; infrabony periodontal defect; fibrin glue; collagen fleece