Research ArticleTissue Engineering

Tissue engineering toward temporomandibular joint disc regeneration

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Science Translational Medicine  20 Jun 2018:
Vol. 10, Issue 446, eaaq1802
DOI: 10.1126/scitranslmed.aaq1802
  • Fig. 1 Formation of tissue-engineered implants from costal chondrocytes and representative gross morphological and histological images.

    (A) Diagram depicting the tissue engineering strategy and timeline from isolation of costal chondrocytes to the implants’ in vivo assessment. Costal cartilage from minipigs was harvested as an allogeneic donor chondrocyte source. The chondrocytes were then expanded in monolayer, redifferentiated in an aggregate culture, and self-assembled into 3D constructs using a scaffold-free approach. Upon construct maturation, the tissue-engineered (TE) implants’ safety and efficacy were assessed via orthotopic implantation into TMJ discs. (B) Tissue-engineered implants’ gross morphology. The tissue-engineered implants’ dimensions shown are 8 mm × 8 mm × 0.4 mm and trimmed before implantation (scale bar, 5 mm; n = 24). (C) Tissue-engineered implants’ histology at time of implantation. Shown are hematoxylin and eosin (H&E)–, PicroSirius Red (PSR)–, and Safranin O/fast green (SafO/FG)–stained sections (scale bars, 500 and 20 μm, respectively; n = 12).

  • Fig. 2 Schematic and intraoperative images demonstrating the intralaminar fenestration surgical technique.

    This technique allowed modeling of TMJ disc thinning, orthotopic implantation, and the tissue-engineered implant’s fixation in the TMJ disc of a minipig. (A, A′, B, and B′) Posterolateral surgical approach to the TMJ disc is demonstrated. (C and C′) The disc is partially released from its posterolateral attachments, gently pulled caudally, and rotated superiorly. (D, D′, E, and E′) Horizontal dissection is performed to create a bilaminar pouch. (F, F′, G, and G′) A 3-mm fenestration defect is made in the pouch’s inferior lamina. (H and H′) The tissue-engineered implant is inserted into the pouch. (I, I′, J, and J′) The pouch is closed with sutures, and the disc attachments are reproduced with Quickanchor Plus and #0 suture. Scale bar, 5 mm.

  • Fig. 3 Histological and immunohistochemical assessment of integration and safety of the tissue-engineered implants.

    (A and B) Gross morphology of the sections obtained from the minipig discs treated with tissue-engineered implants, 2 and 8 weeks after implantation, respectively. (C and D) Low-magnification H&E histology of the disc section containing a tissue-engineered implant, which appears as a purple band at 2 weeks and as a pale pink band at 8 weeks, respectively. (E to H) Higher magnification of the H&E sections containing implants at 2 and 8 weeks after implantation, respectively. (I and J) Immunoreactivity for T cells (CD3) at 2 and 8 weeks, respectively. (K and L) Immunoreactivity for B cells (CD20) at 2 and 8 weeks, respectively. (M and N) Immunoreactivity for macrophages (CD68) at 2 and 8 weeks, respectively. Scale bars, 2 mm (A to H) and 200 μm (I to N).

  • Fig. 4 Gross morphological and histological assessments of the TMJ disc and mandibular heads comparing the tissue-engineered implant–treated group to the untreated group at 8 weeks after implantation (n = 6).

    A, anterior; P, posterior; L, lateral; M, medial; S, superior; Inf, inferior. (A to F) Gross morphology and histology of the mandibular head articular surfaces in the treated versus untreated cases. (G) Gross morphology of the inferior surface of treated TMJ discs. (H) Gross morphology of sagittal (anteroposterior) sections of implant-treated discs. The arrow marks the implant’s location and orientation. The square bracket indicates the location of the healed defect. (I and J) Low- and high-magnification H&E histology images of implant-treated discs. The square bracket indicates the healed defect (I). (K) Gross morphology of the inferior surface of untreated TMJ discs. (L) Gross morphology of sagittal (anteroposterior) sections of untreated discs. The square bracket indicates the open defect’s location. (M and N) Low- and high-magnification H&E histology images of untreated discs. The square bracket indicates the open defect (M).

  • Fig. 5 Quantitative assessment of the efficacy of the tissue-engineered implant to heal the TMJ disc defect.

    (A) Histological appearance of a defect treated with tissue-engineered implant versus untreated discs. Square brackets indicate the defect location. Scale bar, 2 mm. (B) Percent of the combined pouch and fenestration defect perimeter closure indicative of the extent of healing. (C) Young’s modulus values representing the tensile stiffness of the repair tissue that formed in the discs treated with tissue-engineered implant versus untreated discs. (D) Osteoarthritis (OA) scores derived from evaluation of the mandibular heads in implant-treated groups versus untreated groups to measure TMJ degeneration. For all graphs, bars indicate means ± SD (P < 0.05). Student’s t test was used with n = 6, and all data were taken at 8 weeks after implantation.

  • Fig. 6 Integration stiffness at the interface and changes in the biochemical content of the tissue-engineered implants due to adaptive remodeling.

    (A) Young’s modulus at the interface of the tissue-engineered implant or untreated defect. Bars indicate means ± SD (n = 5 to 6; P < 0.05, Student’s t test), and all data were taken at 8 weeks after implantation. (B and C) Representative histology (H&E). Arrowheads show the native-to-native or native-to-implant interface, which is separated by space in the untreated defect. (D) GAG content in the tissue-engineered implant at time zero (n = 6), after 5 weeks of in vitro culture (n = 6), and 8 weeks after implantation (n = 2). (E) Collagen content in the tissue-engineered implant at time zero (n = 6), after 5 weeks of in vitro culture (n = 6), and 8 weeks after implantation (n = 2). (F to H) Representative Safranin O/fast green histochemical staining. (I to K) Representative PicroSirius Red histochemical staining.

Supplementary Materials

  • www.sciencetranslationalmedicine.org/cgi/content/full/10/446/eaaq1802/DC1

    Materials and Methods

    Fig. S1. Tissue-engineered implants’ tensile and compressive properties at various time points in vitro (t = 0 and 5 weeks) and in vivo (t = 8 weeks).

    Fig. S2. Method and outcome of the preliminary in vivo experiment exploring disc perforation defect and suture fixation of tissue-engineered implants (n = 3 shown).

    Fig. S3. Representative external appearances of implantation sites 8 weeks after surgery in tissue-engineered implant–treated groups and empty controls, respectively (n = 6).

    Fig. S4. The mandibular head articulating surfaces’ gross appearances in tissue-engineered implant–treated groups and untreated controls 8 weeks after implantation (n = 6).

    Fig. S5. Low-magnification histology (H&E) of the mandibular heads of tissue-engineered implant–treated groups and untreated controls 8 weeks after implantation (n = 6).

    Fig. S6. Schematic diagram showing specimen preparation for mechanical and histological assessments of the tissue-engineered implant–treated TMJ discs and of the discs with untreated defects.

    Fig. S7. The intralaminar fenestration technique’s ex vivo feasibility validation (n = 3).

    Table S1. Primary data (Excel file).

    References (6265)

  • Supplementary Material for:

    Tissue engineering toward temporomandibular joint disc regeneration

    Natalia Vapniarsky, Le W. Huwe, Boaz Arzi, Meghan K. Houghton, Mark E. Wong, James W. Wilson, David C. Hatcher, Jerry C. Hu, Kyriacos A. Athanasiou*

    *Corresponding author. Email: athens{at}uci.edu

    Published 20 June 2018, Sci. Transl. Med. 10, eaaq1802 (2018)
    DOI: 10.1126/scitranslmed.aaq1802

    This PDF file includes:

    • Materials and Methods
    • Fig. S1. Tissue-engineered implants’ tensile and compressive properties at various time points in vitro (t = 0 and 5 weeks) and in vivo (t = 8 weeks).
    • Fig. S2. Method and outcome of the preliminary in vivo experiment exploring disc perforation defect and suture fixation of tissue-engineered implants (n = 3 shown).
    • Fig. S3. Representative external appearances of implantation sites 8 weeks after surgery in tissue-engineered implant–treated groups and empty controls, respectively (n = 6).
    • Fig. S4. The mandibular head articulating surfaces’ gross appearances in tissue-engineered implant–treated groups and untreated controls 8 weeks after implantation (n = 6).
    • Fig. S5. Low-magnification histology (H&E) of the mandibular heads of tissue-engineered implant–treated groups and untreated controls 8 weeks after implantation (n = 6).
    • Fig. S6. Schematic diagram showing specimen preparation for mechanical and histological assessments of the tissue-engineered implant–treated TMJ discs and of the discs with untreated defects.
    • Fig. S7. The intralaminar fenestration technique’s ex vivo feasibility validation (n = 3).
    • References (6265)

    [Download PDF]

    Other Supplementary Material for this manuscript includes the following:

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