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Li W, Trbojevic S, Pineda-Farias JB, Liu X, Gold MS, Almarza AJ. Mandibular condylar process remodeling in rats with different bite-altering devices. Eur Cell Mater 2023; 45:46-59. [PMID: 36785971 DOI: 10.22203/ecm.v045a04] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/15/2023] Open
Abstract
The objective was to compare different dental splint models and materials for inducing abnormal loading on the gross morphology and histological appearance of the mandibular condylar processes of Sprague Dawley rats. Three different types of dental splints (resin molar, aluminum incisor, stainless-steel incisor) were placed unilaterally to induce occlusal perturbation for 4 weeks. At that time, mandibular condylar processes were assessed by gross appearance and histology. Quantitative measurements were also conducted on the hematoxylin and eosin images for condyle shape. The results showed that although the condylar cartilage was affected by all splint types, the resin molar splint was associated with the most extensive mandibular condylar process remodeling, which was primarily a slant (skewness) of the lateral aspect of the condylar process. Additionally, quantitative measurements on the histological specimens demonstrated that the split and tilt angle of the left (ipsilateral) condylar processes in the resin molar group (124.8 ± 12.7° and 104.1 ± 12.7°, respectively) increased significantly (p < 0.05) when compared to right (contralateral) condylar processes (104.7 ± 5.8°and 91.6 ± 4.4°, respectively). However, no changes were noted on the thickness of the fibrocartilage layer at medial, central, and lateral regions of the condylar process. Another major finding is the high variability of morphology of the naïve animals. Future studies will assess the impact of longer durations of splinting, age, and sex on the remodeling of the mandibular condylar process, allowing for the development of diagnostics and therapies.
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Brown BN, Chung WL, Lowe J, LoPresti ST, Cheetham J, Almarza AJ, Badylak SF. Inductive Remodeling of Extracellular Matrix Scaffolds in the Temporomandibular Joint of Pigs. Tissue Eng Part A 2022; 28:447-457. [PMID: 34809494 PMCID: PMC9131358 DOI: 10.1089/ten.tea.2021.0123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Accepted: 11/04/2021] [Indexed: 11/12/2022] Open
Abstract
The temporomandibular joint (TMJ) disc is a fibrocartilaginous tissue located between the condyle of the mandible and glenoid fossa and articular eminence of the temporal bone. Damage or derangement of the TMJ disc can require surgical removal (discectomy) to restore function. Removal of the TMJ disc, however, leaves the joint space vulnerable to condylar remodeling and degradation, potentially leading to long-term complications. No consistently effective clinical option exists for repair or replacement of the disc following discectomy. This study investigates the use of an acellular scaffold composed of extracellular matrix (ECM) derived from small intestinal submucosa (SIS) as a regenerative template for the TMJ disc in a porcine model. Acellular SIS ECM scaffolds were implanted following discectomy and allowed to remodel for 2, 4, 12, and 24 weeks postimplantation. Remodeling of the implanted device was assessed by longitudinal magnetic resonance imaging (MRI) over the course of 6 months, as well as gross morphologic, histologic, biochemical, and biomechanical analysis (tension and compression) of explanted tissues (disc and condyle) at the time of sacrifice. When the scaffold remained in the joint space, longitudinal MRI demonstrated that the scaffolds promoted new tissue formation within the joint space throughout the study period. The scaffolds were rapidly populated with host-derived cells and remodeled with formation of new, dense, aligned fibrocartilage resembling native tissue as early as 1 month postimplantation. De-novo formation of peripheral muscular and tendinous attachments resembling those in native tissue was also observed. The remodeled scaffolds approached native disc biochemical composition and compressive modulus, and possessed 50% of the tensile modulus within 3 months postimplantation. No degradation of the condylar surface was observed. These results suggest that this acellular bioscaffold fills a medical need for which there is currently no effective treatment and may represent a clinically relevant "off-the-shelf" implant for reconstruction of the TMJ disc.
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Affiliation(s)
- Bryan N. Brown
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
- McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - William L. Chung
- Oral and Maxillofacial Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Jesse Lowe
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Samuel T. LoPresti
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
- McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Jonathan Cheetham
- McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
- Department of Clinical Sciences, Cornell University College of Veterinary Medicine, Cornell University, Ithaca, New York, USA
| | - Alejandro J. Almarza
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
- McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
- Department of Oral and Craniofacial Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
- Center for Craniofacial Regeneration, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Stephen F. Badylak
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
- McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
- Department of Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
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Lee JD, Becker JI, Larkin LM, Almarza AJ, Kapila SD. Morphologic and histologic characterization of sheep and porcine TMJ as large animal models for tissue engineering applications. Clin Oral Investig 2022; 26:5019-5027. [PMID: 35359187 PMCID: PMC9276584 DOI: 10.1007/s00784-022-04472-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Accepted: 03/21/2022] [Indexed: 11/26/2022]
Abstract
Objective The aim of this study was to compare and characterize the structural and ultrastructural organization of the temporomandibular joint (TMJ) between two large animal models for use in the development of tissue engineering strategies. Materials and methods Whole TMJs from sheep and pigs were evaluated with micro-computed tomography (μCT) for morphology and quantitative analyses of bone parameters. Histological examination was performed on the TMJ disc and its attachments to investigate regional distribution of collagen, elastin, and glycosaminoglycans (GAGs). Results μCT analyses demonstrate higher bone mineral density (BMD) in the temporal fossa compared to the mandibular condyle in both species, with this variable being significantly higher in sheep than pig. Quantitative morphometry of the trabecular condyle reveals no statistical differences between the species. Histology demonstrates similar structural organization of collagen and elastin between species. Elastin staining was nearly twofold greater in sheep than in the pig disc. Finally, Safranin-O staining for GAGs in the TMJ disc was localized to the intermediate zone in the sheep but was absent from the porcine disc. Conclusions Our findings show some important differences in the pig and sheep TMJ μCT variables and histology and composition of the disc and discal attachment. These disparities likely reflect differences in masticatory and TMJ functional loading patterns between the two species and provide insights into large animal models towards human applications. Clinical relevance As with the established pig model, the sheep is a suitable large animal model for TMJ research such as regenerative strategies, with specific considerations for design parameters appropriate for human-analog applications.
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Affiliation(s)
- Jonah D Lee
- Department of Molecular & Integrative Physiology, University of Michigan School of Medicine, Ann Arbor, MI, 48109, USA
- Animal Care and Use Office, Office of Research, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Josh I Becker
- Department of Molecular & Integrative Physiology, University of Michigan School of Medicine, Ann Arbor, MI, 48109, USA
| | - Lisa M Larkin
- Department of Molecular & Integrative Physiology, University of Michigan School of Medicine, Ann Arbor, MI, 48109, USA
| | - Alejandro J Almarza
- Department of Oral and Craniofacial Sciences, School of Dental Medicine, University of Pittsburgh, Pittsburgh, PA, 15261, USA
- Center of Craniofacial Regeneration, University of Pittsburgh, Pittsburgh, PA, 15261, USA
- Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, PA, 15261, USA
| | - Sunil D Kapila
- Section of Orthodontics, School of Dentistry, University of California Los Angeles School of Dentistry, 10833 Le Conte Avenue, CHS 33-089, Box 951668, Los Angeles, CA, 90095, USA.
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Li W, Trbojevic S, Almarza AJ. Comparison of the Trueness of Fits of the Biphasic Transverse Isotropic and Kelvin Models to the Tensile Behavior of Temporomandibular Joint Disc. J Biomech Eng 2021; 143:1097184. [PMID: 33537697 DOI: 10.1115/1.4050033] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Indexed: 01/22/2023]
Abstract
This technical brief explores the validity and trueness of fit for using the transverse isotropic biphasic and Kelvin models (first and second order generalized) for characterization of the viscoelastic tensile properties of the temporomandibular joint (TMJ) discs from pigs and goats at a strain rate of 10 mm/min. We performed incremental stress-relaxation tests from 0 to 12% strain, in 4% strain steps on pig TMJ disc samples. In addition, to compare the outcomes of these models between species, we also performed a single-step stress-relaxation test of 10% strain. The transverse isotropic biphasic model yielded reliable fits in reference to the least root mean squared error method only at low strain, while the Kelvin models yielded good fits at both low and high strain, with the second order generalized Kelvin model yielding the best fit. When comparing pig to goat TMJ disc in 10% strain stress-relaxation test, unlike the other two Kelvin models, the transverse isotropic model did not fit well for this larger step. In conclusion, the second order Kelvin model showed the best fits to the experimental data of both species. The transverse isotropic biphasic model did not fit well with the experimental data, although better at low strain, suggesting that the assumption of water flow only applies while uncrimping the collagen fibers. Thus, it is likely that the permeability from the biphasic model is not truly representative, and other biphasic models, such as the poroviscoelastic model, would likely yield more meaningful outputs and should be explored in future works.
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Affiliation(s)
- Wuyang Li
- Department of Oral Biology, School of Dental Medicine, University of Pittsburgh, Pittsburgh, PA 15261; Center of Craniofacial Regeneration, University of Pittsburgh, Pittsburgh, PA 15261
| | - Sara Trbojevic
- Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, PA 15261; Center of Craniofacial Regeneration, University of Pittsburgh, Pittsburgh, PA 15261
| | - Alejandro J Almarza
- Department of Oral Biology, School of Dental Medicine, University of Pittsburgh, Pittsburgh, PA 15261; Center of Craniofacial Regeneration, University of Pittsburgh, Pittsburgh, PA 15261; Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, PA 15261; McGowan Institute of Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA 15261
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Chin AR, Taboas JM, Almarza AJ. Regenerative Potential of Mandibular Condyle Cartilage and Bone Cells Compared to Costal Cartilage Cells When Seeded in Novel Gelatin Based Hydrogels. Ann Biomed Eng 2020; 49:1353-1363. [PMID: 33155145 DOI: 10.1007/s10439-020-02674-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Accepted: 10/21/2020] [Indexed: 11/25/2022]
Abstract
The field of temporomandibular joint (TMJ) condyle regeneration is hampered by a limited understanding of the phenotype and regeneration potential of cells in mandibular condyle cartilage. It has been shown that chondrocytes derived from hyaline and costal cartilage exhibit a greater chondro-regenerative potential in vitro than those from mandibular condylar cartilage. However, our recent in vivo studies suggest that mandibular condyle cartilage cells do have the potential for cartilage regeneration in osteochondral defects, but that bone regeneration is inadequate. The objective of this study was to determine the regeneration potential of cartilage and bone cells from goat mandibular condyles in two different photocrosslinkable hydrogel systems, PGH and methacrylated gelatin, compared to the well-studied costal chondrocytes. PGH is composed of methacrylated poly(ethylene glycol), gelatin, and heparin. Histology, biochemistry and unconfined compression testing was performed after 4 weeks of culture. For bone derived cells, histology showed that PGH inhibited mineralization, while gelatin supported it. For chondrocytes, costal chondrocytes had robust glycosaminoglycan (GAG) deposition in both PGH and gelatin, and compression properties on par with native condylar cartilage in gelatin. However, they showed signs of hypertrophy in gelatin but not PGH. Conversely, mandibular condyle cartilage chondrocytes only had high GAG deposition in gelatin but not in PGH. These appeared to remain dormant in PGH. These results show that mandibular condyle cartilage cells do have innate regeneration potential but that they are more sensitive to hydrogel material than costal cartilage cells.
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Affiliation(s)
- A R Chin
- Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, 409 Salk Pavilion, 335 Sutherland Drive, Pittsburgh, PA, 15213, USA
| | - J M Taboas
- Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, 409 Salk Pavilion, 335 Sutherland Drive, Pittsburgh, PA, 15213, USA
- Department of Oral Biology, School of Dental Medicine, University of Pittsburgh, Pittsburgh, PA, USA
- Center of Craniofacial Regeneration, University of Pittsburgh, Pittsburgh, PA, USA
- McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - A J Almarza
- Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, 409 Salk Pavilion, 335 Sutherland Drive, Pittsburgh, PA, 15213, USA.
- Department of Oral Biology, School of Dental Medicine, University of Pittsburgh, Pittsburgh, PA, USA.
- Center of Craniofacial Regeneration, University of Pittsburgh, Pittsburgh, PA, USA.
- McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, USA.
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Patel A, Zaky SH, Li H, Schoedel K, Almarza AJ, Sfeir C, Sant V, Sant S. Bottom-Up Self-assembled Hydrogel-Mineral Composites Regenerate Rabbit Ulna Defect without Added Growth Factors. ACS Appl Bio Mater 2020; 3:5652-5663. [PMID: 35021797 DOI: 10.1021/acsabm.0c00371] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Hydrogel-based biomaterials have advanced bone tissue engineering approaches in the last decade, through their ability to serve as a carrier for potent growth factor, bone morphogenic protein-2 (BMP-2). However, biophysical properties of hydrogels such as multiscale structural hierarchy and bone extracellular matrix (ECM)-mimetic microarchitecture are underutilized while designing current bone grafts. Incorporation of these properties offers great potential to create a favorable biomimetic microenvironment to harness their regenerative potential. Here, we present our approach to fabricate collagen-inspired bioactive hydrogel scaffolds (referred to as "RegenMatrix") to guide and enhance bone regeneration in a rabbit ulna defect model through the mimicry of multiscale architecture of bone ECM, i.e., native collagen. Specifically, we employed polyelectrolyte complexation to promote bottom-up self-assembly of oppositely charged polysaccharides (chitosan and kappa-carrageenan) at multiple length scales forming fibrils, which further assemble into fibers. The self-assembly and bioinspired scaffold fabrication method resulted in robust cylindrical RegenMatrix with excellent retention of the multiscale architecture and uniform mineral deposition throughout the scaffolds. RegenMatrix, in both nonmineralized and mineralized forms, enhanced bone regeneration in the semiload-bearing ulna defect when compared to the empty defect. RegenMatrix also showed greater histocompatibility without any fibrous tissue formation. Collectively, the RegenMatrix developed in this study has a great potential as a bioactive bone graft without any added growth factors.
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Affiliation(s)
- Akhil Patel
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States
| | - Samer H Zaky
- Center for Craniofacial Regeneration, School of Dental Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States
| | - Hongshuai Li
- Musculoskeletal Growth & Regeneration Laboratory, Department of Orthopaedic Surgery, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States
| | - Karen Schoedel
- Department of Pathology, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States
| | - Alejandro J Almarza
- Center for Craniofacial Regeneration, School of Dental Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States.,Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15219, United States.,McGowan Institute for Regenerative Medicine, Pittsburgh, Pennsylvania 15260, United States
| | - Charles Sfeir
- Center for Craniofacial Regeneration, School of Dental Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States.,Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15219, United States.,McGowan Institute for Regenerative Medicine, Pittsburgh, Pennsylvania 15260, United States
| | - Vinayak Sant
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States
| | - Shilpa Sant
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States.,Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15219, United States.,McGowan Institute for Regenerative Medicine, Pittsburgh, Pennsylvania 15260, United States.,UPMC Hillman Cancer Center, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
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Chin AR, Almarza AJ. Trueness of Fit of Biphasic Transversely Isotropic Parameters Model in the Porcine Temporomandibular Joint Disc and Mandibular Condylar Cartilage and Regional Dependence. J Biomech Eng 2020; 142:1082626. [PMID: 32291443 DOI: 10.1115/1.4046922] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Indexed: 11/08/2022]
Abstract
Temporomandibular joint (TMJ) disorders (TMDs) are not well understood and the mechanical differences between the regions of the mandibular condylar cartilage (MCC) and the TMJ disc have not been thoroughly compared. As of now, there are no commercially available regenerative therapies for the TMJ. Elucidating the mechanical properties of these two structures of the articulating joint will help future efforts in developing tissue engineering treatments of the TMJ. In this study, we evaluate the compressive properties of the porcine disc and mandibular condylar cartilage by performing unconfined compression at 10% strain with 4.5%/min strain rate. Punches (4 mm biopsy) from both tissues were taken from five different regions of both the MCC and TMJ: anterior, posterior, lateral, medial, and central. Previously, theoretical models of compression in the porcine tissue did not fit the whole ramp-relaxation behavior. Thus, the data stress-relaxation was fitted to the biphasic transversely isotropic model, for both the TMJ disc and cartilage. From the results found in the disc, it was found that the posterior region had the highest values in multiple viscoelastic parameters when compared to the other regions. The mandibular condylar cartilage was only found to be significantly different in the transverse modulus between the posterior and lateral regions. Both the TMJ disc and MCC had similar magnitudes of values (for the modulus and other corresponding compressive properties) and behavior under this testing modality.
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Affiliation(s)
- Adam R Chin
- Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, PA 15261
| | - Alejandro J Almarza
- Department of Oral Biology, School of Dental Medicine, University of Pittsburgh, Pittsburgh, PA 15261; Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, PA 15261; Center of Craniofacial Regeneration, University of Pittsburgh, Pittsburgh, PA 15261; McGowan Institute of Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA 15261
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8
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Chen J, Chin A, Almarza AJ, Taboas JM. Hydrogel to guide chondrogenesis versus osteogenesis of mesenchymal stem cells for fabrication of cartilaginous tissues. ACTA ACUST UNITED AC 2020; 15:045006. [PMID: 31470441 DOI: 10.1088/1748-605x/ab401f] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The ideal combination of hydrogel components for regeneration of cartilage and cartilaginous interfaces is a significant challenge because control over differentiation into multiple lineages is necessary. Stabilization of the phenotype of stem cell derived chondrocytes is needed to avoid undesired progression to terminal hypertrophy and tissue mineralization. A novel ternary blend hydrogel composed of methacrylated poly(ethylene glycol) (PEG), gelatin, and heparin (PGH) was designed to guide chondrogenesis by bone marrow derived mesenchymal stem cells (BMSCs) and maintenance of their cartilaginous phenotype. The hydrogel material effects on chondrogenic and osteogenic differentiation by BMSCs were evaluated in comparison to methacrylated gelatin hydrogel (GEL), a conventional bioink used for both chondrogenic and osteogenic applications. PGH and GEL hydrogels were loaded with goat BMSCs and cultured in chondrogenic and osteogenic mediums in vitro over six weeks. The PGH showed no sign of mineral deposition in an osteogenic environment in vitro. To further evaluate material effects, the hydrogels were loaded with adult human BMSCs (hBMSCs) and transforming growth factor β-3 and grown in subcutaneous pockets in mice over eight weeks. Consistent with the in vitro results, the PGH had greater potential to induce chondrogenesis by BMSCs in vivo compared to the GEL as evidenced by elevated gene expression of chondrogenic markers, supporting its potential for stable cartilage engineering. The PGH also showed a greater percentage of GAG positive cells compared to the GEL. Unlike the GEL, the PGH hydrogel exhibited anti-osteogenic effects in vivo as evidenced by negative Von Kossa staining and suppressed gene expression of hypertrophic and osteogenic markers. By nature of their polymer composition alone, the PGH and GEL regulated BMSC differentiation down different osteochondral lineages. Thus, the PGH and GEL are promising hydrogels to regenerate stratified cartilaginous interfacial tissues in situ, such as the mandibular condyle surface, using undifferentiated BMSCs and a stratified scaffold design.
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Affiliation(s)
- Jingming Chen
- Department of Bioengineering; University of Pittsburgh, Pittsburgh, PA 15213, United States of America. Center for Craniofacial Regeneration; University of Pittsburgh, Pittsburgh, PA 15213, United States of America
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Menale C, Robinson LJ, Palagano E, Rigoni R, Erreni M, Almarza AJ, Strina D, Mantero S, Lizier M, Forlino A, Besio R, Monari M, Vezzoni P, Cassani B, Blair HC, Villa A, Sobacchi C. Absence of Dipeptidyl Peptidase 3 Increases Oxidative Stress and Causes Bone Loss. J Bone Miner Res 2019; 34:2133-2148. [PMID: 31295380 PMCID: PMC7203631 DOI: 10.1002/jbmr.3829] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Revised: 06/26/2019] [Accepted: 07/06/2019] [Indexed: 12/29/2022]
Abstract
Controlling oxidative stress through the activation of antioxidant pathways is crucial in bone homeostasis, and impairments of the cellular defense systems involved contribute to the pathogenesis of common skeletal diseases. In this work we focused on the dipeptidyl peptidase 3 (DPP3), a poorly investigated ubiquitous zinc-dependent exopeptidase activating the Keap1-Nrf2 antioxidant pathway. We showed Dpp3 expression in bone and, to understand its role in this compartment, we generated a Dpp3 knockout (KO) mouse model and specifically investigated the skeletal phenotype. Adult Dpp3 KO mice showed a mild growth defect, a significant increase in bone marrow cellularity, and bone loss mainly caused by increased osteoclast activity. Overall, in the mouse model, lack of DPP3 resulted in sustained oxidative stress and in alterations of bone microenvironment favoring the osteoclast compared to the osteoblast lineage. Accordingly, in vitro studies revealed that Dpp3 KO osteoclasts had an inherent increased resorptive activity and ROS production, which on the other hand made them prone to apoptosis. Moreover, absence of DPP3 augmented bone loss after estrogen withdrawal in female mice, further supporting its relevance in the framework of bone pathophysiology. Overall, we show a nonredundant role for DPP3 in the maintenance of bone homeostasis and propose that DPP3 might represent a possible new osteoimmunological player and a marker of human bone loss pathology. © 2019 American Society for Bone and Mineral Research.
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Affiliation(s)
- Ciro Menale
- Consiglio Nazionale delle Ricerche-Istituto di Ricerca Genetica e Biomedica (CNR-IRGB), Milan Unit, Milan, Italy.,Humanitas Clinical and Research Center-Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS), Rozzano, Italy
| | - Lisa J Robinson
- Department of Pathology, West Virginia University, Morgantown, WV, USA
| | - Eleonora Palagano
- Consiglio Nazionale delle Ricerche-Istituto di Ricerca Genetica e Biomedica (CNR-IRGB), Milan Unit, Milan, Italy.,Humanitas Clinical and Research Center-Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS), Rozzano, Italy
| | - Rosita Rigoni
- Consiglio Nazionale delle Ricerche-Istituto di Ricerca Genetica e Biomedica (CNR-IRGB), Milan Unit, Milan, Italy.,Humanitas Clinical and Research Center-Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS), Rozzano, Italy
| | - Marco Erreni
- Unit of Advanced Optical Microscopy, Humanitas Clinical and Research Center-Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS), Rozzano, Italy
| | - Alejandro J Almarza
- Department of Oral Biology, Department of Bioengineering, McGowan Institute of Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Dario Strina
- Consiglio Nazionale delle Ricerche-Istituto di Ricerca Genetica e Biomedica (CNR-IRGB), Milan Unit, Milan, Italy.,Humanitas Clinical and Research Center-Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS), Rozzano, Italy
| | - Stefano Mantero
- Consiglio Nazionale delle Ricerche-Istituto di Ricerca Genetica e Biomedica (CNR-IRGB), Milan Unit, Milan, Italy.,Humanitas Clinical and Research Center-Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS), Rozzano, Italy
| | - Michela Lizier
- Consiglio Nazionale delle Ricerche-Istituto di Ricerca Genetica e Biomedica (CNR-IRGB), Milan Unit, Milan, Italy.,Humanitas Clinical and Research Center-Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS), Rozzano, Italy
| | - Antonella Forlino
- Department of Molecular Medicine, Unit of Biochemistry, University of Pavia, Pavia, Italy
| | - Roberta Besio
- Department of Molecular Medicine, Unit of Biochemistry, University of Pavia, Pavia, Italy
| | - Marta Monari
- Clinical Investigation Laboratory, Humanitas Clinical and Research Center-Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS), Rozzano, Italy
| | - Paolo Vezzoni
- Consiglio Nazionale delle Ricerche-Istituto di Ricerca Genetica e Biomedica (CNR-IRGB), Milan Unit, Milan, Italy.,Humanitas Clinical and Research Center-Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS), Rozzano, Italy
| | - Barbara Cassani
- Consiglio Nazionale delle Ricerche-Istituto di Ricerca Genetica e Biomedica (CNR-IRGB), Milan Unit, Milan, Italy.,Humanitas Clinical and Research Center-Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS), Rozzano, Italy
| | - Harry C Blair
- Veterans' Affairs Medical Center and Department of Pathology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Anna Villa
- Consiglio Nazionale delle Ricerche-Istituto di Ricerca Genetica e Biomedica (CNR-IRGB), Milan Unit, Milan, Italy.,Humanitas Clinical and Research Center-Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS), Rozzano, Italy
| | - Cristina Sobacchi
- Consiglio Nazionale delle Ricerche-Istituto di Ricerca Genetica e Biomedica (CNR-IRGB), Milan Unit, Milan, Italy.,Humanitas Clinical and Research Center-Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS), Rozzano, Italy
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Almarza AJ, Mercuri LG, Arzi B, Gallo LM, Granquist E, Kapila S, Detamore MS. Temporomandibular Joint Bioengineering Conference: Working Together Toward Improving Clinical Outcomes. J Biomech Eng 2019; 142:2737113. [PMID: 31233104 DOI: 10.1115/1.4044090] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Indexed: 12/21/2022]
Abstract
The sixth temporomandibular joint (TMJ) Bioengineering Conference (TMJBC) was held on June 14-15 2018, in Redondo Beach, California, 12 years after the first TMJBC. Speakers gave 30 presentations and came from the United States, Europe, Asia, and Australia. The goal of the conference has remained to foster a continuing forum for bioengineers, scientists, and surgeons and veterinarians to advance technology related to TMJ disorders. These collective multidisciplinary interactions over the past decade have made large strides in moving the field of TMJ research forward. Over the past 12 years, in vivo approaches for tissue engineering have emerged, along with a wide variety of degeneration models, as well as with models occurring in nature. Furthermore, biomechanical tools have become more sensitive and new biologic interventions for disease are being developed. Clinical directives have evolved for specific diagnoses, along with patient-specific biological and immunological responses to TMJ replacement devices alloplastic and/or bioengineered devices. The sixth TMJBC heralded many opportunities for funding agencies to advance the field: (1) initiatives on TMJ that go beyond pain research, (2) more training grants focused on graduate students and fellows, (3) partnership funding with government agencies to translate TMJ solutions, and (4) the recruitment of a critical mass of TMJ experts to participate on grant review panels. The TMJ research community continues to grow and has become a pillar of dental and craniofacial research, and together we share the unified vision to ultimately improve diagnoses and treatment outcomes in patients affected by TMJ disorders.
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Affiliation(s)
- Alejandro J Almarza
- Departments of Oral Biology and Bioengineering, Center for Craniofacial Regeneration, McGowan Institute of Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA 15213
| | - Louis G Mercuri
- Visiting Professor Department of Orthopedic Surgery, Rush University Medical Center, Chicago, IL 60612; TMJ Concepts, Ventura, CA 93003
| | - Boaz Arzi
- Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California, Davis, CA 95616
| | - Luigi M Gallo
- Clinic of Masticatory Disorders, Center of Dental Medicine, University of Zurich, Zurich CH-8031, Switzerland
| | - Eric Granquist
- Department of Oral and Maxillofacial Surgery, University of Pennsylvania, Philadelphia, PA 19104
| | - Sunil Kapila
- Department of Orofacial Sciences, School of Dentistry, University of California San Francisco, San Francisco, CA 94143
| | - Michael S Detamore
- Stephenson School of Biomedical Engineering, The University of Oklahoma, Norman, OK 73019
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Ivanina AV, Borah BM, Vogts A, Malik I, Wu J, Chin AR, Almarza AJ, Kumta P, Piontkivska H, Beniash E, Sokolova IM. Potential trade-offs between biomineralization and immunity revealed by shell properties and gene expression profiles of two closely related Crassostrea species. ACTA ACUST UNITED AC 2018; 221:jeb.183236. [PMID: 29997158 DOI: 10.1242/jeb.183236] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Accepted: 06/29/2018] [Indexed: 12/19/2022]
Abstract
Species of the Ostreidae family are key ecosystem engineers and many of them - including Crassostrea gigas and Crassostreavirginica - are commercially important aquaculture species. Despite similarities in their morphology and ecology, these two species differ in their ability to defend against pathogens, potentially reflecting species-specific differential specialization of hemocytes on immune defense versus biomineralization. To test this hypothesis, we investigated the expression levels of immune- and biomineralization-related genes as well as mineralogical and mechanical properties of the shells and the calcium sequestration ability of the hemocytes of C. gigas and C. virginica The expression of biomineralization-related genes was higher in C. virginica than in C. gigas in multiple tissues including the mantle edge and hemocytes, while the expression of immune genes was higher in the hemocytes of C. gigas Hemocytes of C. virginica contained more calcium (stored intracellularly as calcium carbonate mineral) compared with those of C. gigas Analysis of the adult shells showed that the crystallinity of calcite was higher and the laths of the foliated layer of the shell were thicker in C. virginica than in C. gigas Mechanically, the shells of C. virginica were stiffer, harder and stronger than those of C. gigas Taken together, our results show that the species-specific differences in physiology (such as disease resistance and exoskeleton properties) are reflected at the cellular and molecular levels in the differential specialization of hemocytes on potentially competing functions (immunity and biomineralization) as well as different expression profiles of other tissues involved in biomineralization (such as the mantle edge).
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Affiliation(s)
- Anna V Ivanina
- Department of Biological Sciences, University of North Carolina at Charlotte, Charlotte, NC 28223, USA
| | - Ballav M Borah
- Department of Oral Biology, School of Dental Medicine, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Angela Vogts
- Leibniz Institute for Baltic Sea Research Warnemünde, Warnemünde 18119, Germany
| | - Ifra Malik
- Dietrich School of Arts and Sciences, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - Jingyao Wu
- Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Adam R Chin
- Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Alejandro J Almarza
- Department of Oral Biology, School of Dental Medicine, University of Pittsburgh, Pittsburgh, PA 15261, USA.,Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Prashant Kumta
- Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Helen Piontkivska
- Department of Biological Sciences, Kent State University, Kent, OH 44243, USA
| | - Elia Beniash
- Department of Oral Biology, School of Dental Medicine, University of Pittsburgh, Pittsburgh, PA 15261, USA .,Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Inna M Sokolova
- Department of Marine Biology, Institute of Biosciences, University of Rostock, Rostock 18059, Germany
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Bezamat M, Deeley K, Khaliq S, Letra A, Scariot R, Silva RM, Weber ML, Bussaneli DG, Trevilatto PC, Almarza AJ, Ouyang H, Vieira AR. Are mTOR and Endoplasmic Reticulum Stress Pathway Genes Associated with Oral and Bone Diseases? Caries Res 2018; 53:235-241. [PMID: 30205378 DOI: 10.1159/000492675] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Accepted: 08/03/2018] [Indexed: 12/21/2022] Open
Abstract
The purpose of this cohort study was to identify associations between combined oral and bone disease phenotypes and genes present in cell regulatory pathways. The studied pathways play important roles in cellular growth, proliferation, differentiation, and homeostasis. DNA samples extracted from whole saliva of 3,912 individuals were genotyped and these data analyzed according to dental caries experience, periapical lesions, periodontitis, osteoporosis, or temporomandibular joint discomfort. Samples were obtained from the Dental Registry and DNA Repository project at the University of Pittsburgh. Twenty-seven polymorphisms in eight genes related to mTOR or endoplasmic reticulum stress pathways were selected for genotyping. Allele frequencies and Hardy-Weinberg equilibrium were calculated. Analyses were performed comparing genotypes between affected and unaffected individuals for each phenotype, as well as for the associated phenotypes combined. For all analyses, we used the software PLINK with an alpha of 0.002. Borderline associations with multiple variants of several genes were found, suggesting that both pathways may be involved in the susceptibility to multiple conditions affecting the oral cavity and bones. When combining patients that had concomitant dental caries, periodontitis, and periapical pathology, several markers in RHEB showed statistically significant association. Multiple conditions affecting bone and teeth (i.e., dental caries, periodontitis, periapical lesion formation, and osteoporosis) appear to share similar underlying genetic etiological factors, which allow us to hypothesize that instead of individually, they should be studied in conjunction in human populations.
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Affiliation(s)
- Mariana Bezamat
- Department of Oral Biology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Kathleen Deeley
- Department of Oral Biology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Shahryar Khaliq
- Department of Oral Biology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Ariadne Letra
- Department of Oral Biology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.,Department of Endodontics, University of Texas Health Sciences Center at Houston, Houston, Texas, USA
| | - Rafaela Scariot
- Department of Oral Biology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.,Graduate Program of Health Sciences, PUC-Paraná, Curitiba, Brazil.,Department of Oral Surgery, Positivo University, Curitiba, Brazil
| | - Renato M Silva
- Department of Oral Biology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.,Department of Endodontics, University of Texas Health Sciences Center at Houston, Houston, Texas, USA
| | - Megan L Weber
- Department of Oral Biology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Diego G Bussaneli
- Department of Oral Biology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.,Department of Pediatric Dentistry, UNESP, Araraquara, Brazil
| | | | - Alejandro J Almarza
- Department of Oral Biology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Hongjiao Ouyang
- Department of Endodontics, Texas A&M College of Dentistry, Dallas, Texas, USA
| | - Alexandre R Vieira
- Department of Oral Biology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA, .,Graduate Program of Health Sciences, PUC-Paraná, Curitiba, Brazil,
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Almarza AJ, Brown BN, Arzi B, Ângelo DF, Chung W, Badylak SF, Detamore M. Preclinical Animal Models for Temporomandibular Joint Tissue Engineering. Tissue Eng Part B Rev 2018; 24:171-178. [PMID: 29121815 PMCID: PMC5994143 DOI: 10.1089/ten.teb.2017.0341] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Accepted: 10/05/2017] [Indexed: 01/27/2023]
Abstract
There is a paucity of in vivo studies that investigate the safety and efficacy of temporomandibular joint (TMJ) tissue regeneration approaches, in part due to the lack of established animal models. Review of disease models for study of TMJ is presented herein with an attempt to identify relevant preclinical animal models for TMJ tissue engineering, with emphasis on the disc and condyle. Although degenerative joint disease models have been mainly performed on mice, rats, and rabbits, preclinical regeneration approaches must employ larger animal species. There remains controversy regarding the preferred choice of larger animal models between the farm pig, minipig, goat, sheep, and dog. The advantages of the pig and minipig include their well characterized anatomy, physiology, and tissue properties. The advantages of the sheep and goat are their easier surgical access, low cost per animal, and its high tissue availability. The advantage of the dog is that the joint space is confined, so migration of interpositional devices should be less likely. However, each species has limitations as well. For example, the farm pig has continuous growth until about 18 months of age, and difficult surgical access due to the zygomatic arch covering the lateral aspect of joint. The minipig is not widely available and somewhat costly. The sheep and the goat are herbivores, and their TMJs mainly function in translation. The dog is a carnivore, and the TMJ is a hinge joint that can only rotate. Although no species provides the gold standard for all preclinical TMJ tissue engineering approaches, the goat and sheep have emerged as the leading options, with the minipig as the choice when cost is less of a limitation; and with the dog and farm pig serving as acceptable alternatives. Finally, naturally occurring TMJ disorders in domestic species may be harnessed on a preclinical trial basis as a clinically relevant platform for translation.
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Affiliation(s)
- Alejandro J. Almarza
- Department of Oral Biology, University of Pittsburgh, Pittsburgh, Pennsylvania
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, Pennsylvania
- Center for Craniofacial Regeneration, University of Pittsburgh, Pittsburgh, Pennsylvania
- McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Bryan N. Brown
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, Pennsylvania
- McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Boaz Arzi
- Surgical and Radiological Sciences, School of Veterinary Medicine, University of California, Davis, California
| | - David Faustino Ângelo
- Stomatology Department, Faculty of Medicine, Centro Hospitalar de Setúbal, University of Lisbon, Lisbon, Portugal
| | - William Chung
- Oral and Maxillofacial Surgery, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania
| | - Stephen F. Badylak
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, Pennsylvania
- McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania
- Department of Surgery, McGowan Institute of Regenerative Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Michael Detamore
- Stephenson School of Biomedical Engineering, The University of Oklahoma, Norman, Oklahoma
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Lowe J, Almarza AJ. A review of in-vitro fibrocartilage tissue engineered therapies with a focus on the temporomandibular joint. Arch Oral Biol 2017; 83:193-201. [PMID: 28787640 DOI: 10.1016/j.archoralbio.2017.07.013] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2017] [Revised: 07/19/2017] [Accepted: 07/20/2017] [Indexed: 12/11/2022]
Abstract
The inability of fibrocartilage, specifically the temporomandibular joint (TMJ) disc, to regenerate and remodel following injury presents a unique problem for clinicians. Tissue engineering then offers a potential regenerative therapy. In vitro testing provides a valuable screening tool for potential tissue engineered solutions. The conclusions drawn for TMJ in vitro research were compared against state of the art fibrocartilage studies in the knee meniscus, and annulus fibrosus of the intervertebral disc (IVD). For TMJ disc regeneration, in vitro tissue engineered approaches, focused on cellular therapies with fibrochondrocytes, have displayed an inability to produce enough collagen, as well as an inability to recapitulate native mechanical properties. Biomaterial approaches have recapitulated the native properties of the TMJ disc, but their in vivo efficacy has yet to be determined. By comparison, the knee meniscus field is the most progressive in the use of stem cells as a cell source. The knee meniscus field has moved away from measuring mechanical properties, and are instead more focused on biochemistry and gene expression. IVD studies mainly use electrospun scaffolds, and have produced the best success in mechanical properties. The TMJ field, in comparison to knee meniscus and IVD, needs to employ stem cell therapies, new biomaterials and manufacturing techniques, and cutting edge molecular assays, in future in vitro approaches to screen for viable technologies to move to in vivo studies.
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Affiliation(s)
- Jesse Lowe
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15260, United States; Center for Craniofacial Regeneration, University of Pittsburgh, Pittsburgh, PA 15260, United States.
| | - Alejandro J Almarza
- Department of Oral Biology, University of Pittsburgh, Pittsburgh, PA 15260, United States; Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15260, United States; Center for Craniofacial Regeneration, University of Pittsburgh, Pittsburgh, PA 15260, United States; McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA 15260, United States.
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15
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Zaky SH, Lee KW, Gao J, Jensen A, Verdelis K, Wang Y, Almarza AJ, Sfeir C. Poly (glycerol sebacate) elastomer supports bone regeneration by its mechanical properties being closer to osteoid tissue rather than to mature bone. Acta Biomater 2017; 54:95-106. [PMID: 28110067 DOI: 10.1016/j.actbio.2017.01.053] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2016] [Revised: 01/10/2017] [Accepted: 01/17/2017] [Indexed: 11/28/2022]
Abstract
Mechanical load influences bone structure and mass. Arguing the importance of load-transduction, we investigated the mechanisms inducing bone formation using an elastomeric substrate. We characterized Poly (glycerol sebacate) (PGS) in vitro for its mechanical properties, compatibility with osteoprogenitor cells regarding adhesion, proliferation, differentiation under compression versus static cultures and in vivo for the regeneration of a rabbit ulna critical size defect. The load-transducing properties of PGS were compared in vitro to a stiffer poly lactic-co-glycolic-acid (PLA/PGA) scaffold of similar porosity and interconnectivity. Under cyclic compression for 7days, we report focal adhesion kinase overexpression on the less stiff PGS and upregulation of the transcription factor Runx2 and late osteogenic markers osteocalcin and bone sialoprotein (1.7, 4.0 and 10.0 folds increase respectively). Upon implanting PGS in the rabbit ulna defect, histology and micro-computed tomography analysis showed complete gap bridging with new bone by the PGS elastomer by 8weeks while minimal bone formation was seen in empty controls. Immunohistochemical analysis demonstrated the new bone to be primarily regenerated by recruited osteoprogenitors cells expressing periostin protein during early phase of maturation similar to physiological endochondral bone development. This study confirms PGS to be osteoconductive contributing to bone regeneration by recruiting host progenitor/stem cell populations and as a load-transducing substrate, transmits mechanical signals to the populated cells promoting differentiation and matrix maturation toward proper bone remodeling. We hence conclude that the material properties of PGS being closer to osteoid tissue rather than to mineralized bone, allows bone maturation on a substrate mechanically closer to where osteoprogenitor/stem cells differentiate to develop mature load-bearing bone. SIGNIFICANCE OF SIGNIFICANCE The development of effective therapies for bone and craniofacial regeneration is a foremost clinical priority in the mineralized tissue engineering field. Currently at risk are patients seeking treatment for craniofacial diseases, traumas and disorders including birth defects such as cleft lip and palate, (1 in 525 to 714 live births), craniosynostosis (300-500 per 1,000,000 live births), injuries to the head and face (20 million ER visits per year), and devastating head and neck cancers (8000 deaths and over 30,000 new cases per year). In addition, approximately 6.2 million fractures occur annually in the United States, of which 5-10% fail to heal properly, due to delayed or non-union [1], and nearly half of adults aged 45-65 have moderate to advanced periodontitis with associated alveolar bone loss, which, if not reversed, will lead to the loss of approximately 6.5 teeth/individual [2]. The strategies currently available for bone loss treatment largely suffer from limitations in efficacy or feasibility, necessitating further development and material innovation. Contemporary materials systems themselves are indeed limited in their ability to facilitate mechanical stimuli and provide an appropriate microenvironment for the cells they are designed to support. We propose a strategy which aims to leverage biocompatibility, biodegradability and material elasticity in the creation of a cellular niche. Within this niche, cells are mechanically stimulated to produce their own extracellular matrix. The hypothesis that mechanical stimuli will enhance bone regeneration is supported by a wealth of literature showing the effect of mechanical stimuli on bone cell differentiation and matrix formation. Using mechanical stimuli, to our knowledge, has not been explored in vivo in bone tissue engineering applications. We thus propose to use an elastomeric platform, based on poly(glycerol sebacate (PGS), to mimic the natural biochemical environment of bone while enabling the transmission of mechanical forces. In this study we report the material's load-transducing ability as well as falling mechanically closer to bone marrow and osteoid tissue rather than to mature bone, allowed osteogenesis and bone maturation. Defying the notion of selecting bone regeneration scaffolds based on their relative mechanical comparability to mature bone, we consider our results in part novel for the new application of this elastomer and in another fostering for reassessment of the current selection criteria for bone scaffolds.
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Affiliation(s)
- S H Zaky
- Center for Craniofacial Regeneration, Department of Oral Biology, University of Pittsburgh, USA
| | - K W Lee
- Department of Bioengineering, University of Pittsburgh, USA
| | - J Gao
- Department of Bioengineering, University of Pittsburgh, USA
| | - A Jensen
- Department of Chemistry, University of Pittsburgh Dietrich School of Arts and Sciences, USA
| | - K Verdelis
- Center for Craniofacial Regeneration, Department of Oral Biology, University of Pittsburgh, USA; McGowan Institute for Regenerative Medicine, University of Pittsburgh, USA
| | - Y Wang
- Department of Bioengineering, University of Pittsburgh, USA; McGowan Institute for Regenerative Medicine, University of Pittsburgh, USA
| | - A J Almarza
- Center for Craniofacial Regeneration, Department of Oral Biology, University of Pittsburgh, USA; Department of Bioengineering, University of Pittsburgh, USA; McGowan Institute for Regenerative Medicine, University of Pittsburgh, USA
| | - C Sfeir
- Center for Craniofacial Regeneration, Department of Oral Biology, University of Pittsburgh, USA; McGowan Institute for Regenerative Medicine, University of Pittsburgh, USA.
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16
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Salash JR, Hossameldin RH, Almarza AJ, Chou JC, McCain JP, Mercuri LG, Wolford LM, Detamore MS. Potential Indications for Tissue Engineering in Temporomandibular Joint Surgery. J Oral Maxillofac Surg 2015; 74:705-11. [PMID: 26687154 DOI: 10.1016/j.joms.2015.11.008] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2015] [Revised: 11/05/2015] [Accepted: 11/10/2015] [Indexed: 12/29/2022]
Abstract
PURPOSE Musculoskeletal tissue engineering has advanced to the stage where it has the capability to engineer temporomandibular joint (TMJ) anatomic components. Unfortunately, there is a paucity of literature identifying specific indications for the use of TMJ tissue engineering solutions. The objective of this study was to establish an initial set of indications and contraindications for the use of engineered tissues for replacement of TMJ anatomic components. FINDINGS There was consensus among the authors that the management of patients requiring TMJ reconstruction as the result of 1) irreparable condylar trauma, 2) developmental or acquired TMJ pathology in skeletally immature patients, 3) hyperplasia, and 4) documented metal hypersensitivities could be indications for bioengineered condyle and ramus TMJ components. There was consensus that Wilkes stage III internal derangement might be an indication for use of a bioengineered TMJ disc or possibly even a disc-like bioengineered "fossa liner." However, there was some controversy as to whether TMJ arthritic disease (e.g., osteoarthritis) and reconstruction after failed alloplastic devices should be indications. Further research is required to determine whether tissue-engineered TMJ components could be a viable option for such cases. Contraindications for the use of bioengineered TMJ components could include patients with TMJ disorders and multiple failed surgeries, parafunctional oral habits, persistent TMJ infection, TMJ rheumatoid arthritis, and ankylosis unless the underlying pathology can be resolved. CONCLUSIONS Biomedical engineers must appreciate the specific indications that might warrant TMJ bioengineered structures, so that they avoid developing technologies in search of problems that might not exist for patients and clinicians. Instead, they should focus on identifying and understanding the problems that need resolution and then tailor technologies to address those specific situations. The aforementioned indications and contraindications are designed to serve as a guide to the next generation of tissue engineers in their strategic development of technologies to address specific clinical issues.
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Affiliation(s)
- Jean R Salash
- Graduate Student, Bioengineering Graduate Program, University of Kansas, Lawrence, KS
| | - Reem H Hossameldin
- Oral Surgeon, Department of Oral and Maxillofacial Surgery, Faculty of Oral Medicine, Cairo University, Cairo, Egypt
| | - Alejandro J Almarza
- Associate Professor, Departments of Oral Biology and Bioengineering, McGowan Institute of Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA
| | - Joli C Chou
- Clinical Associate Professor, The Craniofacial Center of Western New York, Buffalo, NY
| | - Joseph P McCain
- Clinical Associate Professor and Chief, Department of Oral and Maxillofacial Surgery, Herbert Wertheim College of Medicine, Florida International University, Miami; Department of Oral and Maxillofacial Surgery, Baptist Health Systems, Miami, FL
| | - Louis G Mercuri
- Visiting Professor, Department of Orthopedic Surgery, Rush University Medical Center, Chicago, IL; TMJ Concepts, Ventura, CA
| | - Larry M Wolford
- Clinical Professor, Departments of Oral and Maxillofacial Surgery and Orthodontics, Texas A&M University Health Science Center, Baylor College of Dentistry, Baylor University Medical Center, Dallas, TX
| | - Michael S Detamore
- Professor, Department of Chemical and Petroleum Engineering and Bioengineering Graduate Program, University of Kansas, Lawrence, KS.
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Henderson SE, Tudares MA, Gold MS, Almarza AJ. Analysis of pain in the rabbit temporomandibular joint after unilateral splint placement. J Oral Facial Pain Headache 2015; 29:193-202. [PMID: 25905538 DOI: 10.11607/ofph.1371] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
AIMS To determine whether behavioral, anatomical, and physiologic endpoints widely used to infer the presence of pain in rodent models of temporomandibular disorders (TMD) were applicable to the rabbit model of TMD associated with altered joint loading. METHODS Unilateral molar dental splints were used to alter temporomandibular joint (TMJ) loading. Changes in nociceptive threshold were assessed with a mechanical probing of the TMJ region on nine splinted and three control rabbits. Fos-like immunoreacitivty in the trigeminal subnucleus caudalis was assessed with standard immunohistochemical techniques from three splinted and six control animals. Retrogradely labeled TMJ afferents were studied with patch-clamp electrophysiologic techniques from three splinted and three control animals. Remodeling of TMJ condyles was assessed by histologic investigations of three splinted and three control animals. A Student t test or a Mann-Whitney U test was used with significance set at P < .05 to compare splinted to control samples. RESULTS While variable, there was an increase in mechanical sensitivity in splinted rabbits relative to controls. The increase in Fos+ cells in splinted rabbits was also significant relative to naïve controls (86 ± 8 vs 64 ± 15 cells/section, P < .05). The rheobase (364 ± 80 pA) and action potential threshold (-31.2 ± 2.0 mV) were higher in TMJ afferents from splinted rabbits compared to controls (99 ± 22 pA and -38.0 ± 2.0 mV, P < .05). There was significant remodeling in the condylar fibrocartilage layers as manifested by a change in glycosaminoglycan distribution and a loss of defined cell layers. CONCLUSION Behavioral and anatomical results were consistent with an increase in nociceptive signaling in concert with condylar remodeling driven by altered TMJ loading. Changes in excitability and action potential waveform were consistent with possible compensatory changes of TMJ afferents for an overall increase in afferent drive associated with joint degeneration. These compensatory changes may reflect pain-adaption processes that many patients with TMJ disorders experience.
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Henderson SE, Tudares MA, Tashman S, Almarza AJ. Decreased Temporomandibular Joint Range of Motion in a Model of Early Osteoarthritis in the Rabbit. J Oral Maxillofac Surg 2015; 73:1695-705. [PMID: 25889371 DOI: 10.1016/j.joms.2015.03.042] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2015] [Revised: 03/16/2015] [Accepted: 03/16/2015] [Indexed: 10/23/2022]
Abstract
PURPOSE Analysis of mandibular biomechanics could help with understanding the mechanisms of temporomandibular joint (TMJ) disorders (TMJDs), such as osteoarthritis (TMJ-OA), by investigating the effects of injury or disease on TMJ movement. The objective of the present study was to determine the functional kinematic implications of mild TMJ-OA degeneration caused by altered occlusion from unilateral splints in the rabbit. MATERIALS AND METHODS Altered occlusion of the TMJ was mechanically induced in rabbits by way of a unilateral molar dental splint (n = 3). TMJ motion was assessed using 3-dimensional (3D) skeletal kinematics twice, once before and once after 6 weeks of splint placement with the splints removed, after allowing 3 days of recovery. The relative motion of the condyle to the fossa and the distance between the incisors were tracked. RESULTS An overall decrease in the range of joint movement was observed at the incisors and in the joint space between the condyle and fossa. The incisor movement decreased from 7.0 ± 0.5 mm to 6.2 ± 0.5 mm right to left, from 5.5 ± 2.2 mm to 4.6 ± 0.8 mm anterior to posterior, and from 13.3 ± 1.8 mm to 11.6 ± 1.4 mm superior to inferior (P < .05). The total magnitude of the maximum distance between the points on the condyle and fossa decreased from 3.6 ± 0.8 mm to 3.1 ± 0.6 mm for the working condyle and 2.8 ± 0.4 mm to 2.5 ± 0.4 mm for the balancing condyle (P < .05). The largest decreases were seen in the anteroposterior direction for both condyles. CONCLUSION Determining the changes in condylar movement might lead to a better understanding of the early predictors in the development of TMJ-OA and determining when the symptoms become a chronic, irreversible problem.
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Affiliation(s)
- Sarah E Henderson
- Graduate Student Researcher, Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA
| | - Mauro A Tudares
- Research Technician, Department of Oral Biology, University of Pittsburgh, Pittsburgh, PA
| | - Scott Tashman
- Associate Professor, Department of Orthopaedic Surgery, University of Pittsburgh, Pittsburgh, PA
| | - Alejandro J Almarza
- Associate Professor, Department of Bioengineering; Department of Oral Biology; and McGowan Institute of Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA.
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Henderson SE, Lowe JR, Tudares MA, Gold MS, Almarza AJ. Temporomandibular joint fibrocartilage degeneration from unilateral dental splints. Arch Oral Biol 2014; 60:1-11. [PMID: 25247778 DOI: 10.1016/j.archoralbio.2014.08.022] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2014] [Revised: 08/15/2014] [Accepted: 08/30/2014] [Indexed: 12/31/2022]
Abstract
OBJECTIVE The objective of this study was to determine the extent to which altered loading in the temporomandibular joint (TMJ), as might be associated with a malocclusion, drives degeneration of articulating surfaces in the TMJ. We therefore sought to quantify the effects of altered joint loading on the mechanical properties and biochemical content and distribution of TMJ fibrocartilage in the rabbit. DESIGN Altered TMJ loading was induced with a 1mm splint placed unilaterally over the maxillary and mandibular molars for 6 weeks. At that time, TMJ fibrocartilage was assessed by compression testing, biochemical content (collagen, glycosaminoglycan (GAG), DNA) and distribution (histology), for both the TMJ disc and the condylar fibrocartilage. RESULTS There were no changes in the TMJ disc for any of the parameters tested. The condylar fibrocartilage from the splinted animals was significantly stiffer and the DNA content was significantly lower than that in control animals. There was significant remodeling in the condylar fibrocartilage layers as manifested by a change in GAG and collagen II distribution and a loss of defined cell layers. CONCLUSIONS A connection between the compressive properties of TMJ condylar fibrocartilage after 6 weeks of splinting and the changes in histology was observed. These results suggest a change in joint loading leads to condylar damage, which may contribute to pain associated with at least some forms of TMJ disease.
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Affiliation(s)
- Sarah E Henderson
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA
| | - Jesse R Lowe
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA
| | - Mauro A Tudares
- Department of Oral Biology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Michael S Gold
- Department of Anesthesiology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Alejandro J Almarza
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA; Department of Oral Biology, University of Pittsburgh, Pittsburgh, PA, USA; McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, USA.
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Henderson SE, Verdelis K, Maiti S, Pal S, Chung WL, Chou DT, Kumta PN, Almarza AJ. Magnesium alloys as a biomaterial for degradable craniofacial screws. Acta Biomater 2014; 10:2323-32. [PMID: 24384125 DOI: 10.1016/j.actbio.2013.12.040] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2013] [Revised: 12/12/2013] [Accepted: 12/17/2013] [Indexed: 10/25/2022]
Abstract
Recently, magnesium (Mg) alloys have received significant attention as potential biomaterials for degradable implants, and this study was directed at evaluating the suitability of Mg for craniofacial bone screws. The objective was to implant screws fabricated from commercially available pure Mg and alloy AZ31 in vivo in a rabbit mandible. First, Mg and AZ31 screws were compared to stainless steel screws in an in vitro pull-out test and determined to have a similar holding strength (∼40N). A finite-element model of the screw was created using the pull-out test data, and this model can be used for future Mg alloy screw design. Then, Mg and AZ31 screws were implanted for 4, 8 and 12weeks, with two controls of an osteotomy site (hole) with no implant and a stainless steel screw implanted for 12weeks. Microcomputed tomography was used to assess bone remodeling and Mg/AZ31 degradation, both visually and qualitatively through volume fraction measurements for all time points. Histological analysis was also completed for the Mg and AZ31 at 12weeks. The results showed that craniofacial bone remodeling occurred around both Mg and AZ31 screws. Pure Mg had a different degradation profile than AZ31; however, bone growth occurred around both screw types. The degradation rate of both Mg and AZ31 screws in the bone marrow space and the muscle were faster than in the cortical bone space at 12weeks. Furthermore, it was shown that by alloying Mg, the degradation profile could be changed. These results indicate the promise of using Mg alloys for craniofacial applications.
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Zaky SH, Hangadora CK, Tudares MA, Gao J, Jensen A, Wang Y, Sfeir C, Almarza AJ. Poly (glycerol sebacate) elastomer supports osteogenic phenotype for bone engineering applications. Biomed Mater 2014; 9:025003. [DOI: 10.1088/1748-6041/9/2/025003] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Zaky SH, Lee KW, Gao J, Jensen A, Close J, Wang Y, Almarza AJ, Sfeir C. Poly(Glycerol Sebacate) Elastomer: A Novel Material for Mechanically Loaded Bone Regeneration. Tissue Eng Part A 2014; 20:45-53. [DOI: 10.1089/ten.tea.2013.0172] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Samer Helal Zaky
- Department of Oral Biology, Center for Craniofacial Regeneration, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Kee-Won Lee
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Jin Gao
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Adrianna Jensen
- Department of Chemistry, Dietrich School of Arts and Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - John Close
- Department of Dental Public Health and Information Management, School of Dental Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Yadong Wang
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, Pennsylvania
- McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Alejandro J. Almarza
- Department of Oral Biology, Center for Craniofacial Regeneration, University of Pittsburgh, Pittsburgh, Pennsylvania
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, Pennsylvania
- McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Charles Sfeir
- Department of Oral Biology, Center for Craniofacial Regeneration, University of Pittsburgh, Pittsburgh, Pennsylvania
- McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania
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Hagandora CK, Gao J, Wang Y, Almarza AJ. Poly (glycerol sebacate): a novel scaffold material for temporomandibular joint disc engineering. Tissue Eng Part A 2012; 19:729-37. [PMID: 23157344 DOI: 10.1089/ten.tea.2012.0304] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The preponderance of temporomandibular joint (TMJ) disorders involving TMJ disc injury inspires the need to further explore tissue engineering strategies. The objective of this study was to examine the potential of poly (glycerol sebacate) (PGS), a biocompatible, biodegradable elastomer, as a porous scaffold material for the TMJ disc. Goat fibrochondrocytes were seeded on PGS at three seeding densities (25, 50, 100 million cells/mL scaffold), respectively, and cultured for 24 h, 2 weeks, and 4 weeks. The resulting histological, biochemical, and biomechanical properties were determined. Histological staining revealed an abundance of both collagen and glycosaminoglycans (GAG) throughout the high seeding density scaffolds at 4 weeks. There was also a significant increase in the cellular content in all groups over the four-week period, showing that the scaffolds promoted cell attachment and proliferation. The PGS scaffolds supported the deposition of large quantities of extracellular matrix, with differences noted between seeding density groups. At 4 weeks, the medium and high seeding density groups had significantly more collagen per scaffold (181±46 μg and 218±24 μg, respectively) than the low seeding density group (105±28 μg) (p<0.001). At 4 weeks, the medium and high seeding density groups also had a significantly higher GAG content per scaffold (702±253 μg and 773±187 μg, respectively), than the low seeding density group (324±73 μg) (p<0.001). The compression tangent modulus was significantly greater at 4 weeks than 24 h (123.6±86 kPa and 26.2±5 kPa, respectively) (seeding density groups combined) (p<0.001), with no differences between seeding groups at each time point. After 4 weeks, the tangent modulus of the low seeding density group was in a similar range of the goat TMJ disc (180±127 kPa compared to 304±141 kPa, respectively). The results show that cell seeding density and culture time do have an effect on both the biochemical and biomechanical properties of PGS scaffolds. These findings demonstrate that PGS has great potential as a scaffold material for TMJ disc engineering.
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Affiliation(s)
- Catherine K Hagandora
- Department of Bioengineering, Center for Craniofacial Regeneration, McGowan Institute of Regenerative Medicine, School of Dental Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
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Liu L, Alonso V, Guo L, Tourkova I, Henderson SE, Almarza AJ, Friedman PA, Blair HC. Na+/H+ exchanger regulatory factor 1 (NHERF1) directly regulates osteogenesis. J Biol Chem 2012; 287:43312-21. [PMID: 23109343 DOI: 10.1074/jbc.m112.422766] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Bone formation requires synthesis, secretion, and mineralization of matrix. Deficiencies in these processes produce bone defects. The absence of the PDZ domain protein Na(+)/H(+) exchange regulatory factor 1 (NHERF1) in mice, or its mutation in humans, causes osteomalacia believed to reflect renal phosphate wasting. We show that NHERF1 is expressed by mineralizing osteoblasts and organizes Na(+)/H(+) exchangers (NHEs) and the PTH receptor. NHERF1-null mice display reduced bone formation and wide mineralizing fronts despite elimination of phosphate wasting by dietary supplementation. Bone mass was normal, reflecting coordinated reduction of bone resorption and formation. NHERF1-null bone had decreased strength, consistent with compromised matrix quality. Mesenchymal stem cells from NHERF1-null mice showed limited osteoblast differentiation but enhanced adipocyte differentiation. PTH signaling and Na(+)/H(+) exchange were dysregulated in these cells. Osteoclast differentiation from monocytes was unaffected. Thus, NHERF1 is required for normal osteoblast differentiation and matrix synthesis. In its absence, compensatory mechanisms maintain bone mass, but bone strength is reduced.
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Affiliation(s)
- Li Liu
- Department of Pathology, Physiology & Cell Biology, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, USA
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Fisher MB, Liang R, Jung HJ, Kim KE, Zamarra G, Almarza AJ, McMahon PJ, Woo SLY. Potential of healing a transected anterior cruciate ligament with genetically modified extracellular matrix bioscaffolds in a goat model. Knee Surg Sports Traumatol Arthrosc 2012; 20:1357-65. [PMID: 22143425 PMCID: PMC9583725 DOI: 10.1007/s00167-011-1800-x] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/08/2011] [Accepted: 11/17/2011] [Indexed: 01/14/2023]
Abstract
PURPOSE Biological augmentation to heal a torn anterior cruciate ligament (ACL) has gained significant interest. This study examined the potential advantages of using extracellular matrix (ECM) bioscaffolds from galactosyl-α(1,3)galactose deficient pigs to heal the transected ACL. METHODS In 16 skeletally mature goats, the ACL in the right hindlimb was transected and repaired. In 9 of these animals, an ECM sheet was wrapped around the injury site and with an ECM hydrogel injected into the transected site. The remaining 7 animals were treated with suture repair only. The left hindlimb served as a sham-operated control. RESULTS After 12 weeks, the healing ACL in the ECM-treated group showed an abundance of continuous neo-tissue formation, while only limited tissue growth was found after suture repair only. The cross-sectional area of the ACL from the ECM-treated group was similar to sham-operated controls (n.s.) and was 4.5 times those of the suture repair group (P < 0.05). The stiffness of the femur-ACL-tibia complexes from the ECM-treated group was 2.4 times those of the suture repair group (P < 0.05). Furthermore, these values reached 48% of the sham-operated controls (53 ± 19 N/mm and 112 ± 21 N/mm, respectively, P < 0.05). CONCLUSIONS The application of an ECM bioscaffold and hydrogel was found to accelerate the healing of a transected ACL following suture repair in the goat model with limited tissue hypertrophy and improvement in some of its biomechanical properties. Although more work is necessary to fully restore the function of the normal ACL, these early results offer a potential new approach to aid ACL healing.
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Affiliation(s)
- Matthew B. Fisher
- Department of Bioengineering, Musculoskeletal Research Center, Swanson School of Engineering, University of Pittsburgh, 405 Center for Bioengineering, 300 Technology Drive, Pittsburgh, PA 15219, USA
| | - Rui Liang
- Department of Bioengineering, Musculoskeletal Research Center, Swanson School of Engineering, University of Pittsburgh, 405 Center for Bioengineering, 300 Technology Drive, Pittsburgh, PA 15219, USA
| | - Ho-Joong Jung
- Department of Bioengineering, Musculoskeletal Research Center, Swanson School of Engineering, University of Pittsburgh, 405 Center for Bioengineering, 300 Technology Drive, Pittsburgh, PA 15219, USA,Department of Orthopaedic Surgery, College of Medicine, Chung-Ang University, Seoul, Korea
| | - Kwang E. Kim
- Department of Bioengineering, Musculoskeletal Research Center, Swanson School of Engineering, University of Pittsburgh, 405 Center for Bioengineering, 300 Technology Drive, Pittsburgh, PA 15219, USA
| | - Giovanni Zamarra
- Department of Bioengineering, Musculoskeletal Research Center, Swanson School of Engineering, University of Pittsburgh, 405 Center for Bioengineering, 300 Technology Drive, Pittsburgh, PA 15219, USA
| | - Alejandro J. Almarza
- Department of Bioengineering, Musculoskeletal Research Center, Swanson School of Engineering, University of Pittsburgh, 405 Center for Bioengineering, 300 Technology Drive, Pittsburgh, PA 15219, USA
| | - Patrick J. McMahon
- Department of Bioengineering, Musculoskeletal Research Center, Swanson School of Engineering, University of Pittsburgh, 405 Center for Bioengineering, 300 Technology Drive, Pittsburgh, PA 15219, USA
| | - Savio L-Y. Woo
- Department of Bioengineering, Musculoskeletal Research Center, Swanson School of Engineering, University of Pittsburgh, 405 Center for Bioengineering, 300 Technology Drive, Pittsburgh, PA 15219, USA
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Brown BN, Chung WL, Almarza AJ, Pavlick MD, Reppas SN, Ochs MW, Russell AJ, Badylak SF. Inductive, scaffold-based, regenerative medicine approach to reconstruction of the temporomandibular joint disk. J Oral Maxillofac Surg 2012; 70:2656-68. [PMID: 22365981 DOI: 10.1016/j.joms.2011.12.030] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2011] [Revised: 12/22/2011] [Accepted: 12/23/2011] [Indexed: 01/22/2023]
Abstract
PURPOSE A device composed of extracellular matrix (ECM) was investigated as an inductive template in vivo for reconstruction of the temporomandibular joint (TMJ) disk after discectomy. MATERIALS AND METHODS A scaffold material composed of porcine-derived ECM was configured to mimic the shape and size of the TMJ. This device was implanted in a canine model of bilateral TMJ discectomy. After discectomy, 1 side was repaired with an ECM scaffold material and the contralateral side was left empty as a control. At 6 months after implantation, the joint space was opened, the joints were evaluated for signs of gross pathologic degenerative changes, and newly formed tissue was excised for histologic, biochemical, and biomechanical analysis. RESULTS The results showed that implantation of an initially acellular material supported the formation of site-appropriate, functional host tissue that resembled that of the native TMJ disk. Furthermore, this prevented gross degenerative changes in the temporal fossa and mandibular condyle. No tissue formation and mild to severe gross pathologic changes were observed in the contralateral controls. CONCLUSIONS These results suggest that an ECM-based bioscaffold could represent an off-the-shelf solution for TMJ disk replacement.
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Affiliation(s)
- Bryan N Brown
- Department of Bioengineering and McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA 15219, USA
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Hagandora CK, Chase TW, Almarza AJ. A comparison of the mechanical properties of the goat temporomandibular joint disc to the mandibular condylar cartilage in unconfined compression. J Dent Biomech 2011; 2011:212385. [PMID: 21765875 PMCID: PMC3134092 DOI: 10.4061/2011/212385] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/07/2011] [Revised: 03/14/2011] [Accepted: 03/24/2011] [Indexed: 11/20/2022]
Abstract
The aim of this study was to make a comparison of the compressive properties of the goat temporomandibular joint (TMJ) disc to the mandibular condylar cartilage (MCC) and to explore the transversely isotropic biphasic model. Samples taken mediolaterally from three regions of the TMJ disc and MCC were tested in unconfined compression at strain levels ranging from 10% to 50% and then assessed for biochemical content. The results indicated that the TMJ disc exhibits a significantly greater tangent modulus than the MCC from 20% to 50% strain with values ranging from 729 ± 267 to 2413 ± 406 kPa and 363 ± 169 to 1677 ± 538 kPa, respectively (P < .05). The collagen content of the TMJ disc was significantly greater than the MCC, while the opposite held for the glycosaminoglycan (GAG) and DNA content. The results emphasize fundamental differences between the articulating tissues of the TMJ.
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Affiliation(s)
- Catherine K Hagandora
- Department of Oral Biology, Department of Bioengineering, Center for Craniofacial Regeneration, McGowan Institute of Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, 15261, USA
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Almarza AJ, Yang G, Woo SLY, Nguyen T, Abramowitch SD. Positive changes in bone marrow-derived cells in response to culture on an aligned bioscaffold. Tissue Eng Part A 2009; 14:1489-95. [PMID: 18694325 DOI: 10.1089/ten.tea.2007.0422] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Previous studies have shown that cultured cells align with the local topography of their substrate following a concept called "contact guidance." Additionally, if the topography is highly aligned, the cells produce newly synthesized matrix that is also aligned. The objective of this study was to elucidate the positive effect of cell seeding on an elongated porcine small intestinal submucosa (SIS), which has been shown to improve ligament and tendon healing, by measuring the cellular response as a result of the changes in alignment. Because elongation is known to align the fibers of SIS through recruitment along the direction of elongation, we hypothesized that rabbit bone marrow-derived cells (BMDCs) seeded on SIS with improved fiber alignment would increase the expression and production of collagen following the concept of contact guidance. Using the small-angle light-scattering technique, it was found that a 15% elongation together with BMDC seeding on SIS (elongated, seeded group) improved its alignment of collagen fibers up to 16 times more than no elongation and no BMDC seeding (non-elongated, non-seeded group). Furthermore, BMDCs were also aligned along the direction of elongation and showed 200% greater collagen type I gene expression in the elongated, seeded group than in Petri dish controls. More importantly, the production of collagen was also 24% greater. The results of this study demonstrate that alignment of a bioscaffold can result in positive changes in cellular response, making the bioscaffold more attractive for functional tissue engineering to potentially enhance healing of ligaments and tendons.
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Affiliation(s)
- Alejandro J Almarza
- Musculoskeletal Research Center, Department of Bioengineering, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
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Abstract
The temporomandibular joint (TMJ) disc is a specialized fibrocartilaginous tissue. When the disc becomes an obstacle and becomes damaged, surgeons have no choice but to perform a discectomy. Tissue engineering may provide a novel treatment modality for TMJ disorder patients who undergo discectomy. No studies have been conducted on the most favourable media for TMJ disc cells. The objective of the current study was to examine the effects on biochemical and biomechanical properties of varying ascorbic acid concentrations (0, 25, or 50 μg/ml) on TMJ disc cells seeded on non-woven PGA scaffolds. The ascorbic acid concentration of the 25 μg/ml group resulted in more effective cell seeding of the scaffolds, with 1.53 million cells per construct, by comparison with the 0 and 50 μg/ml groups which had 1.20 million and 1.32 million cells per scaffold respectively. At week 4, the 25 μg/ml group had a higher collagen content than the 0 μg/ml group, with 30.4 ± 2.7 and 24.9 ± 3.3 μg of collagen per construct respectively. The 25 μg/ml group had a higher aggregate modulus than the 50 μg/ml group, with values of 6.1 ± 1.3 and 4.0 ± 0.9 kPa respectively at week 4. The results of this study indicate that the use of 25 μg/ml of ascorbic acid in culture media is effective for the tissue engineering of the TMJ disc, significantly outperforming media without or with 50 μg/ml of ascorbic acid.
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Affiliation(s)
- A C Bean
- Department of Bioengineering, Rice University, Houston, Texas 77251, USA
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Abstract
The effects of mechanical stimuli on TMJ disc cells have yet to be investigated. This study examined for the first time the effect of constant and intermittent hydrostatic pressure (HP) on TMJ disc cells. Guided by studies on articular chondrocytes, the chosen amplitude was 10 MPa, the frequency was 1 Hz for intermittent HP, and the duration was 4 h. A one-time application of the HP stimulus was applied in 2-D and 3-D for gene expression studies. A duty cycle of 2 days on, 1 day off for 1 week of HP stimulus was used for biochemical content studies. In monolayer, the intermittent HP regimen increased collagen II expression, while constant HP increased collagen I expression when compared to the non-loaded control. However, the overall expression of collagen I was much higher than collagen II in both constant and intermittent HP. The expression results correlated well with gross morphology, histology, and biochemical content. At Week 1, the intermittent HP group had a lower content of collagen, 7.5 +/- 0.2 microg/construct, than the non-loaded control group, 18.2 +/- 4.0 microg/construct. The constant HP group showed the highest amount of collagen, 24.5 +/- 1.6 microg/construct. These data show that constant HP at 10 MPa for 4 h produces more collagen I than do the non-loaded control or intermittent HP at 10 MPa and 1 Hz.
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Almarza AJ, Bean AC, Baggett LS, Athanasiou KA. Biochemical analysis of the porcine temporomandibular joint disc. Br J Oral Maxillofac Surg 2006; 44:124-8. [PMID: 16011866 DOI: 10.1016/j.bjoms.2005.05.002] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2004] [Accepted: 05/02/2005] [Indexed: 10/25/2022]
Abstract
Tissue engineering can be a boon in treating lesions of the disc in the temporomandibular joint (TMJ). Unfortunately, little is known about its biochemical content, so we analysed the discs of six slaughtered pigs. We measured the content and distribution of total DNA, glycosaminoglycan, and collagen. The mean (S.D.) content of DNA was 0.14% (0.08%) of the dry weight, of glycosaminoglycan 0.96% (0.39%), and of collagen 68.2% (14.5%). There were no significant differences from top to bottom, but from front to back the smallest concentration of glycosaminoglycan was in the posterior band, and the highest concentration of collagen was in the intermediate zone. The concentrations of DNA and glycosaminoglycan were higher in the medial than in the lateral area of the disc.
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Affiliation(s)
- A J Almarza
- Department of Bioengineering, MS 142, Rice University, P.O. Box 1892, Houston, TX 77251, USA
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Detamore MS, Hegde JN, Wagle RR, Almarza AJ, Montufar-Solis D, Duke PJ, Athanasiou KA. Cell type and distribution in the porcine temporomandibular joint disc. J Oral Maxillofac Surg 2006; 64:243-8. [PMID: 16413896 PMCID: PMC4474408 DOI: 10.1016/j.joms.2005.10.009] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
PURPOSE Surprisingly little is known about the cellular composition of the temporomandibular joint (TMJ) disc, which is a crucial piece of the puzzle in tissue engineering efforts. Toward this end, cell types were identified and quantified regionally in the TMJ disc. MATERIALS AND METHODS Porcine TMJ discs were examined by histology, electron microscopy, and immunohistochemistry. Histology consisted of hematoxylin and eosin staining to identify regional variation of cell type and cell numbers. Transmission electron microscopy was used to elucidate differences in organelle content and pericellular matrix between TMJ disc cells and chondrocytes from hyaline cartilage. Immunohistochemistry was used to assess the presence of smooth and skeletal muscle character in the TMJ disc. RESULTS The overall ratio of fibroblasts to chondrocyte-like cells in the TMJ disc was approximately 2.35 to 1, with the highest relative number of chondrocyte-like cells in the intermediate zone. Electron microscopy revealed distinct differences between TMJ disc chondrocyte-like cells and chondrocytes from hyaline cartilage with respect to organelles and the pericellular region. Immunostaining identified smooth muscle in the form of vessels, which were most prominent in the anterior band. Skeletal muscle was not observed. CONCLUSION The cells of the TMJ disc are distinctly different from cells of hyaline cartilage, and consequently should not be referred to as chondrocytes. TMJ disc cells are comprised of heterogeneously distributed subpopulations, with fibroblasts predominating over fibrochondrocytes.
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Affiliation(s)
- Michael S Detamore
- Department of Chemical and Petroleum Engineering, University of Kansas, Lawrence, KS 66045-7609, USA
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Almarza AJ, Athanasiou KA. Evaluation of three growth factors in combinations of two for temporomandibular joint disc tissue engineering. Arch Oral Biol 2005; 51:215-21. [PMID: 16105643 DOI: 10.1016/j.archoralbio.2005.07.002] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2004] [Revised: 05/30/2005] [Accepted: 07/07/2005] [Indexed: 10/25/2022]
Abstract
Tissue engineering of the temporomandibular joint disc could be a great value in treatments that require discectomy. Potential benefit has been found in the use of three growth factors: insulin-like growth factor-I, basic fibroblast growth factor and transforming growth factor-beta1 in maintaining disc-like tissue in culture. In the present study, these three growth factors were combined in pairs and tested at two different concentrations over a 6-week period. All combinations of the growth factors appear to be beneficial since only three-quarters of the control constructs (without growth factors) retained mechanical integrity, compared with the majority of constructs exposed to growth factors. Importantly, the concentrations of the presented growth factors had a significant impact on the cellularity of constructs at Week 6. When a high concentration of the two growth factors was used, at least twice as many cells remained in the constructs compared with controls.
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Affiliation(s)
- A J Almarza
- Department of Bioengineering MS 142, Rice University, P.O. Box 1892, Houston, TX 77251, USA
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Abstract
Tissue engineering may provide a better treatment modality for postoperative discectomy patients. The TMJ disc is an ideal candidate for tissue engineering approaches because of its lack of an intrinsic regenerative ability. Unfortunately, basic knowledge related to TMJ disc tissue engineering is still at an infancy level and not on par to that related to articular cartilage tissue engineering. The objective of this study was to examine the effects of initial cell density of TMJ disc cells seeded in nonwoven poly-glycolic acid (PGA) scaffolds on the biochemical and biomechanical properties of constructs examined at 0, 3, and 6 weeks after seeding. Low, medium, and high seeding densities were chosen to be 15, 30, and 120 million cells per ml of scaffold, which were seeded using a spinner flask. Significant differences were found temporally and as a function of seeding density in morphology, total collagen, GAG content, and permeability of the constructs, but not in aggregate modulus. The high seeding density group outperformed the low and medium groups in collagen and GAG content at all time points measured. The high-density group produced a total of 55.37 +/- 3.56 microg of collagen per construct, maintained 15.77 +/- 1.86 microg of GAG per construct, and only shrunk to 50% of the original scaffold size. Permeability of the constructs at 6 weeks was decreased by 70% compared to 0 weeks.
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Detamore MS, Orfanos JG, Almarza AJ, French MM, Wong ME, Athanasiou KA. Quantitative analysis and comparative regional investigation of the extracellular matrix of the porcine temporomandibular joint disc. Matrix Biol 2005; 24:45-57. [PMID: 15749001 PMCID: PMC4474406 DOI: 10.1016/j.matbio.2004.11.006] [Citation(s) in RCA: 93] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2004] [Revised: 11/16/2004] [Accepted: 11/16/2004] [Indexed: 11/18/2022]
Abstract
Characterization of the extracellular matrix of the temporomandibular joint (TMJ) disc is crucial to advancing efforts in tissue engineering the disc. However, the current literature is incomplete and often contradictory in its attempts to describe the nature of the TMJ disc matrix. The aim of this study was to identify the variation of key matrix components along the three axes of the porcine disc using ELISAs to quantify these matrix components, immunohistochemistry to identify their regional distribution, and SEM to examine collagen fiber diameter and orientation. The overall GAG content of the TMJ disc (including the dermatan sulfate proteoglycans) was 5.3+/-1.2% of the dry weight. Chondroitin sulfate, which comprised 74% of this total GAG content, was 4.4, 8.2, and 164 times more abundant than dermatan sulfate proteoglycan, keratan sulfate, and hyaluronic acid, respectively. In general, these GAGs were most concentrated in the intermediate zone of the TMJ disc, appearing in dense clusters, and least concentrated in the posterior band. Additionally, chondroitin sulfate was more abundant medially than laterally. Collagen II was discovered in trace amounts, with higher relative amounts in the intermediate zone. Collagen fibers were observed to run primarily in a ring-like fashion around the periphery of the disc and anteroposteriorly through the intermediate zone, with a mean fiber diameter of 18+/-9 mum. Characterization studies of the TMJ disc, including prior biomechanical and cell studies along with the current study of the extracellular matrix, collectively reveal a distinct character of the intermediate zone of the disc compared to its anterior and posterior bands.
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Affiliation(s)
- Michael S Detamore
- Department of Chemical & Petroleum Engineering, University of Kansas, 1530 W. 15th St., Room 4132, Lawrence, KS 66045-7609, USA.
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Abstract
Temporomandibular joint (TMJ) disk removal, or diskectomy, is a detrimental yet necessary surgery for patients with extremely displaced disks. Tissue engineering is an enticing methodology for improvement of the postoperative outcome of diskectomy. Unfortunately, the field of tissue engineering of the TMJ disk is only in the early stages of development. The initial objective of this investigation was to study the cellular response of TMJ disk cells in alginate culture. However, a marked decrease in cell population and the lack of detection of extracellular matrix (ECM) products did not support the use of alginate culture. The second objective was then to attempt TMJ disk cell culture in polyglycolic acid (PGA) nonwoven meshes. However, as suitable seeding methods for TMJ disk cells on PGA had not been determined, three techniques were selected for study: spinner flask, orbital shaker, and a novel pelleting technique. PGA constructs maintained cellularity throughout the culture period, and scaffolds seeded with the spinner flask produced about 35 microg of collagen per construct. Thus, as evidenced by the production of a major extracellular component, PGA nonwoven meshes seeded with TMJ disk cells, using a spinner flask, may be a first positive culturing step in tissue engineering the TMJ disk.
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Abstract
Tissues like the temporomandibular joint (TMJ) disc and the knee meniscus are often mistakenly viewed as a tantamount to hyaline cartilage, largely due to the absence of a comprehensive understanding of the distinguishing properties of cartilaginous tissues. Because of this confusion, fibrocartilaginous tissue engineering attempts may not be based on suitable experimental designs. Fibrocartilaginous tissues are markedly different than hyaline cartilage; however, the dearth of knowledge related to their cellular and biochemical composition, as well as their biomechanical characteristics, is stunning. Hyaline articular cartilage is exclusively composed of chondrocytes that produce primarily type II collagen, whereas the TMJ disc and the knee meniscus have a mixed cell population of fibroblasts and cells similar to chondrocytes, which predominantly secrete type I collagen. Additionally, fibrocartilaginous tissues have a low glycosaminoglycan content, a low compressive modulus, and a high tensile modulus when compared to hyaline cartilage. Therefore, it is crucial for fibrocartilaginous tissue engineering attempts to be tissue-specific, utilizing the knowledge of the distinct and unique properties of these tissues. At the same time, advances and insights related to the science and engineering aspect of hyaline cartilage regeneration must be carefully considered for the in vitro engineering of fibrocartilaginous tissues.
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