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Archives of Oral Biology Oct 2011The periodontal ligament (PDL) is a key contributor to the process of regeneration of the periodontium. The heterogeneous nature of the PDL tissue, its development... (Review)
Review
The periodontal ligament (PDL) is a key contributor to the process of regeneration of the periodontium. The heterogeneous nature of the PDL tissue, its development during early adulthood, and the different conditions to which the PDL tissue is exposed to in vivo impart on the PDL unique characteristics that may be of consequence during its cultivation in vitro. Several factors affecting the in vivo setting influence the behaviour of PDL fibroblasts in culture. The purpose of this review is to address distinct factors that influence the behaviour of PDL fibroblasts in culture -in vivo-in vitro transitions, cell identification/isolation markers, primary PDL cultures and cell lines, tooth-specific factors, and donor-specific factors. Based on the reviewed studies, the authors recommendations include the use of several identification markers to confirm cell identity, use of primary cultures at early passage to maintain unique PDL heterogeneic characteristics, and noting donor conditions such as age, systemic health status, and tooth health status. Continued efforts will expand our understanding of the in vitro and in vivo behaviour of cells, with the goal of orchestrating optimal periodontal regeneration. This understanding will lead to improved evidence-based rationales for more individualized and predictable periodontal regenerative therapies.
Topics: Biomarkers; Cell Culture Techniques; Cell Line; Cell Separation; Cells, Cultured; Fibroblasts; Humans; Periodontal Ligament; Regeneration
PubMed: 21470594
DOI: 10.1016/j.archoralbio.2011.03.003 -
Periodontal ligament regulatory role in experimental diabetic rat model of periodontium remodelling.Folia Morphologica 2022Diabetes, among multiple systemic harmful health issues, also may deteriorate normal regenerative and reparative functions of periodontium. The aim of this research was...
BACKGROUND
Diabetes, among multiple systemic harmful health issues, also may deteriorate normal regenerative and reparative functions of periodontium. The aim of this research was to study the role of periodontal ligament in tissue remodelling under the orthodontic appliance stimulation in two rat experimental models (healthy Wistar rats and Goto-Kakizaki, rodent model of non-obese type 2 diabetes).
MATERIALS AND METHODS
Four groups of rats were defined: Wistar (WI; n = 8) and Goto-Kakizaki (GK; n = 8) control groups without orthodontic appliances, and Wistar (n = 16) and Goto-Kakizaki (n = 16) appliance groups with orthodontic appliances. After 42 days, rats were sacrificed and histopathology descriptive analysis about periodontal ligament and adjacent structures was performed as well as cellularity of periodontal ligament and Kappa curvature of tooth roots were measured.
RESULTS
Goto-Kakizaki control rats showed statistically significantly higher cellularity in comparison with Wistar control rats (p < 0.001). Both applied groups (WI 44.63 ± 6.68; GK 79.58 ± 10.06) also showed statistically significantly higher cellularity (p < 0.001) in comparison with control groups (WI 34.48 ± 6.92; GK 45.31 ± 11.18). Applied groups (WI 0.197 ± 0.2; GK 0.126 ± 0.083) had statistically significant higher values of Kappa curvature in comparison with control groups (WI 0.023 ± 0.011; GK 0.037 ± 0.011) (WI appliance vs. WI control: p < 0.001; GK appliance vs. GK control: p < 0.05). Agitated periodontal ligament caused different degrees of cementoclasia and additionally dentinoclasia, altering the natural root curvature.
CONCLUSIONS
Although not significantly different (WI and GK appliance groups) according to degree of molar roots odontoclasia, higher cellularity of agitated GK periodontal ligament could be influencing factor for, as previously reported, elevated osteoclast mobilization and possible prolonged periodontium reconstitution.
Topics: Rats; Animals; Periodontal Ligament; Rats, Wistar; Diabetes Mellitus, Type 2; Periodontium; Models, Theoretical
PubMed: 34642931
DOI: 10.5603/FM.a2021.0101 -
Stem Cells and Development Aug 2019Inflammatory conditions affect periodontal ligament (PDL) homeostasis and diminish its regenerative capacity. The complexity of biological activities during an...
Inflammatory conditions affect periodontal ligament (PDL) homeostasis and diminish its regenerative capacity. The complexity of biological activities during an inflammatory response depends on genetic and epigenetic mechanisms. To characterize the epigenetic changes in response to periodontal pathogens we have focused on histone lysine methylation as a relatively stable chromatin modification involved in the epigenetic activation and repression of transcription and a prime candidate mechanism responsible for the exacerbated and prolonged response of periodontal cells and tissues to dental plaque biofilm. To determine the effect of inflammatory conditions on histone methylation profiles, related gene expression and cellular functions of human periodontal ligament (hPDL) progenitor cells, a hPDL cell culture system was subjected to bacterial cell wall toxin exposure [lipopolysaccharide (LPS)]. Chromatin immunoprecipitation-on-chip analysis revealed that healthy PDL cells featured high enrichment levels for the active H3K4me3 mark at , , and gene promoters, whereas there were high occupancy levels for the repressive H3K27me3 marks at , and gene promoters. In response to LPS, H3K27me3 enrichment increased on extracellular matrix and osteogenesis lineage gene promoters, whereas H3K4me3 enrichment increased on the promoters of inflammatory response genes, suggestive of an involvement of epigenetic mechanisms in periodontal lineage differentiation and in the coordination of the periodontal inflammatory response. On a gene expression level, LPS treatment downregulated , , and expression and upregulated , , and gene expression. LPS also greatly affected PDL progenitor function, including a reduction in proliferation and differentiation potential and an increase in cell migration capacity. Confirming the role of epigenetic mechanisms in periodontal inflammatory conditions, our studies highlight the significant role of histone methylation mechanisms and modification enzymes in the inflammatory response to LPS bacterial cell wall toxins and periodontal stem cell function.
Topics: Cell Differentiation; Cells, Cultured; DNA Methylation; Epigenesis, Genetic; Gene Expression Regulation; Histone Methyltransferases; Histones; Humans; Inflammation; Lipopolysaccharides; Osteogenesis; Periodontal Ligament; Periodontitis; Protein Processing, Post-Translational; Stem Cells
PubMed: 31218921
DOI: 10.1089/scd.2019.0125 -
Journal of Dental Research Feb 2021The most fundamental function of an epithelial tissue is to act as a barrier, regulating interactions between the external environment and the body. This barrier...
The most fundamental function of an epithelial tissue is to act as a barrier, regulating interactions between the external environment and the body. This barrier function typically requires a contiguous cell layer but since teeth penetrate the oral epithelium, a modified barrier has evolved, called the junctional epithelium (JE). In health, the JE attaches to the tooth, sealing the inside of the body against oral micro-organisms. Breakdown of the JE barrier results in periodontal ligament (PDL) disintegration, alveolar bone resorption, and ultimately tooth loss. Using lineage tracing and DNA pulse-chase analyses, we identified an anatomical location in the JE that supported both fast- and slow-cycling Wnt-responsive stem cells that contributed to self-renewal of the tissue. Stem cells produced daughter cells with an extraordinarily high rate of turnover that maintained JE integrity for 1.4 y in mice. Blocking cell proliferation via a chemotherapeutic agent 5-fluorouracil (5-Fu) eliminated fast-cycling stem cells, which caused JE degeneration, PDL destruction, and bone resorption. Upon removal of 5-Fu, slow-cycling stem cells regenerated both the structure and barrier function of the JE. Taken together, our studies identified a stem cell population in the JE and have potential clinical implications for prevention and treatment of periodontitis.
Topics: Animals; Epithelial Attachment; Epithelium; Gingiva; Mice; Periodontal Ligament; Stem Cells; Tooth
PubMed: 32985318
DOI: 10.1177/0022034520960125 -
European Cells & Materials Oct 2021Due to the complexity of the structure of the tooth periodontium, regeneration of the full tooth attachment is not a trivial task. There is also a gap in models that can...
Due to the complexity of the structure of the tooth periodontium, regeneration of the full tooth attachment is not a trivial task. There is also a gap in models that can represent human tooth attachment in vitro and in vivo. The aim of this study was to develop a bilayered in vitro construct that simulated the tooth periodontal ligament and attached alveolar bone, for the purpose of tissue regeneration and investigation of physiological and orthodontic loading. Two types of materials were used to develop this construct: sol-gel 60S10Mg derived scaffold, representing the hard tissue component of the periodontium, and commercially available Geistlich Bio-Gide® collagen membrane, representing the soft tissue component of the tooth attachment. Each scaffold was dynamically seeded with human periodontal ligament cells (HPDLCs). Scaffolds were either cultured separately, or combined in a bilayered construct, for 2 weeks. Characterisation of the individual scaffolds and the bilayered constructs included biological characterisation (cell viability, scanning electron microscopy to confirm cell attachment, gene expression of periodontium regeneration markers), and mechanical characterisation of scaffolds and constructs. HPDLCs enjoyed a biocompatible 3-dimensional environment within the bilayered construct components. There was no drop in cellular gene expression in the bilayered construct, compared to the separate scaffolds.
Topics: Humans; Periodontal Ligament; Periodontium; Tissue Engineering; Tissue Scaffolds; Tooth
PubMed: 34632563
DOI: 10.22203/eCM.v042a17 -
International Journal of Environmental... Jan 2023This study examines 0.6 N and 1.2 N as the maximum orthodontic force for periodontal ligament (PDL) at multiple levels of periodontal breakdown, and the relationships...
This study examines 0.6 N and 1.2 N as the maximum orthodontic force for periodontal ligament (PDL) at multiple levels of periodontal breakdown, and the relationships with the ischemic, necrotic, and resorptive risks. Additionally, this study evaluates if Tresca failure criteria is more adequate for the PDL study. Eighty-one 3D models (from nine patients; nine models/patients) with the 2nd lower premolar and different degrees of bone loss (0-8 mm) where subjected to intrusion, extrusion, rotation, translation, and tipping movements. Tresca shear stress was assessed individually for each movement and bone loss level. Rotation and translation produced the highest PDL stresses, while intrusion and extrusion determined the lowest. Apical and middle third PDL stresses were lower than the cervical stress. In intact periodontium, the amount of shear stress produced by the two investigated forces was lower than the 16 KPa of the maximum physiological hydrostatic pressure (MHP). In reduced periodontium (1-8 mm tissue loss), the apical amount of PDL shear stress was lower than MHP for both applied forces, while cervically for rotation, translation and tipping movements exceeded 16 KPa. Additionally, 1.2 N could be used in intact periodontium (i.e., without risks) and for the reduced periodontium only in the apical and middle third of PDL up to 8 mm of bone loss. However, for avoiding any resorptive risks, in the cervical third of PDL, the rotation, translation, and tipping movements require less than 0.2-0.4 N of force after 4 mm of loss. Tresca seems to be more adequate for the study of PDL than other criteria.
Topics: Humans; Periodontal Ligament; Tooth Movement Techniques; Finite Element Analysis; Periodontium; Stress, Mechanical; Computer Simulation; Models, Biological
PubMed: 36767254
DOI: 10.3390/ijerph20031889 -
International Journal of Molecular... Jan 2021The aim of the study was to clarify whether orthodontic forces and periodontitis interact with respect to the anti-apoptotic molecules superoxide dismutase 2 (SOD2) and...
The aim of the study was to clarify whether orthodontic forces and periodontitis interact with respect to the anti-apoptotic molecules superoxide dismutase 2 (SOD2) and baculoviral IAP repeat-containing protein 3 (BIRC3). SOD2, BIRC3, and the apoptotic markers caspases 3 (CASP3) and 9 (CASP9) were analyzed in gingiva from periodontally healthy and periodontitis subjects by real-time PCR and immunohistochemistry. SOD2 and BIRC3 were also studied in gingiva from rats with experimental periodontitis and/or orthodontic tooth movement. Additionally, SOD2 and BIRC3 levels were examined in human periodontal fibroblasts incubated with and/or subjected to mechanical forces. Gingiva from periodontitis patients showed significantly higher SOD2, BIRC3, CASP3, and CASP9 levels than periodontally healthy gingiva. SOD2 and BIRC3 expressions were also significantly increased in the gingiva from rats with experimental periodontitis, but the upregulation of both molecules was significantly diminished in the concomitant presence of orthodontic tooth movement. In vitro, SOD2 and BIRC3 levels were significantly increased by , but this stimulatory effect was also significantly inhibited by mechanical forces. Our study suggests that SOD2 and BIRC3 are produced in periodontal infection as a protective mechanism against exaggerated apoptosis. In the concomitant presence of orthodontic forces, this protective anti-apoptotic mechanism may get lost.
Topics: Animals; Apoptosis; Baculoviral IAP Repeat-Containing 3 Protein; Caspase 3; Caspase 9; Cells, Cultured; Fibroblasts; Fusobacterium nucleatum; Gene Expression Regulation; Gingiva; Host-Pathogen Interactions; Humans; Periodontal Ligament; Periodontium; Rats; Superoxide Dismutase
PubMed: 33435582
DOI: 10.3390/ijms22020591 -
Mediators of Inflammation 2020Resistin, a proinflammatory adipokine, is elevated in many inflammatory diseases. However, little is known about its performance in periodontitis. The present study is...
Resistin, a proinflammatory adipokine, is elevated in many inflammatory diseases. However, little is known about its performance in periodontitis. The present study is aimed at evaluating resistin expression and synthesis in periodontal cells and tissues under inflammatory/microbial stress in addition to its effects on the periodontium. In vivo, 24 male rats were randomly divided into two groups: control and ligature-induced periodontal disease. After 6 and 12 days, animals were sacrificed to analyze gene expression of adipokines, bone loss, inflammation, and resistin synthesis. In vitro, human periodontal ligament (PDL) fibroblasts were used to evaluate the expression of resistin after inflammatory stimuli. In addition, PDL fibroblasts were exposed to resistin to evaluate its role on soft and hard tissue metabolism markers. The periodontitis group demonstrated significant bone loss, an increase in the number of inflammatory cells and vascular structures, an increase in resistin expression and synthesis, and a decrease in the expression of adiponectin, leptin, and its functional receptor. PDL fibroblasts showed a significant increase in resistin expression and synthesis in response to the inflammatory stimulus by IL-1. Resistin induced an increase in cytokine expression and a decrease in the regulation of some hard tissue and matrix formation genes in PDL fibroblasts. These data indicate that resistin is produced by periodontal cells and tissues, and this effect is enhanced by inflammatory stimuli. Moreover, resistin seems to interfere with soft and hard tissue metabolism during periodontitis by reducing markers related to matrix formation and bone tissue.
Topics: Animals; Bone and Bones; Fibroblasts; Gingiva; Humans; Inflammation; Periodontal Ligament; Periodontitis; Periodontium; Phenotype; Rats; Resistin
PubMed: 32410876
DOI: 10.1155/2020/9817095 -
Life Sciences Sep 2021Stimulation of β-adrenergic receptors (βAR) in osteoblasts by isoproterenol (ISO) was shown to induce Vascular Endothelial Growth Factor (VEGF) and angiogenesis in...
AIMS
Stimulation of β-adrenergic receptors (βAR) in osteoblasts by isoproterenol (ISO) was shown to induce Vascular Endothelial Growth Factor (VEGF) and angiogenesis in long bones. We thus aimed to determine the vascular response of mandibular tissues to βAR stimulation regarding blood vessel formation.
MAIN METHODS
Six-week-old wild-type C57BL6 female mice received daily intraperitoneal injections of ISO or phosphate buffered saline (PBS) for 1 month. Hemimandibles and tibias were collected for immunolocalization of endomucin, tyrosine hydroxylase (TH), neuropeptide Y (NPY) and norepinephrine transporter (NET). Moreover, Vegfa, Il-1 β, Il-6, Adrb2 and Rankl mRNA expression was assessed in mandibles and tibias 2 h after PBS or ISO treatment.
KEY FINDINGS
Despite similar sympathetic innervation and Adrb2 expression between mandibular tissues and tibias, with TH and NPY+ nerve fibers distributed around blood vessels, ISO treatment did not increase endomucin+ vessel area or the total number of endomucin+ vessels in any of the regions investigated (alveolar bone, periodontal ligament, and dental pulp). Consistent with these results, the expression of Vegfα, Il-6, Il-1β, and Rankl in the mandibular molar region did not change following ISO administration. We detected high expression of NET by immunofluorescence in mandible alveolar osteoblasts, osteocytes, and periodontal ligament fibroblasts, in addition to significantly higher Net expression by qPCR compared to the tibia from the same animals.
SIGNIFICANCE
These findings indicate a differential response to βAR agonists between mandibular and tibial tissues, since the angiogenic potential of sympathetic outflow observed in long bones is absent in periodontal tissues.
Topics: Adrenergic beta-Agonists; Animals; Female; Isoproterenol; Mice; Mice, Inbred C57BL; Periodontal Ligament; Receptors, Adrenergic, beta-2; Vascular Endothelial Growth Factor A
PubMed: 34186048
DOI: 10.1016/j.lfs.2021.119776 -
Journal of Dental Research Dec 2021The WNT/β-catenin signaling pathway plays a central role in the biology of the periodontium, yet the function of specific extracellular WNT ligands remains poorly...
The WNT/β-catenin signaling pathway plays a central role in the biology of the periodontium, yet the function of specific extracellular WNT ligands remains poorly understood. By using a inducible transgenic mouse model targeting -expressing alveolar osteoblasts, odontoblasts, and cementoblasts, we demonstrate that the WNT ligand WNT1 is a strong promoter of cementum and alveolar bone formation in vivo. We induced expression for 1, 3, or 9 wk in Wnt1Tg mice and analyzed them at the age of 6 wk and 12 wk. Micro-computed tomography (CT) analyses of the mandibles revealed a 1.8-fold increased bone volume after 1 and 3 wk of expression and a 3-fold increased bone volume after 9 wk of expression compared to controls. In addition, the alveolar ridges were higher in Wnt1Tg mice as compared to controls. Nondecalcified histology demonstrated increased acellular cementum thickness and cellular cementum volume after 3 and 9 wk of expression. However, 9 wk of expression was also associated with periodontal breakdown and ectopic mineralization of the pulp. The composition of this ectopic matrix was comparable to those of cellular cementum as demonstrated by quantitative backscattered electron imaging and immunohistochemistry for noncollagenous proteins. Our analyses of 52-wk-old mice after 9 wk of expression revealed that expression affects mandibular bone and growing incisors but not molar teeth, indicating that influences only growing tissues. To further investigate the effect of on cementoblasts, we stably transfected the cementoblast cell line (OCCM-30) with a vector expressing -HA and performed proliferation as well as differentiation experiments. These experiments demonstrated that promotes proliferation but not differentiation of cementoblasts. Taken together, our findings identify, for the first time, as a critical regulator of alveolar bone and cementum formation, as well as provide important insights for harnessing the WNT signal pathway in regenerative dentistry.
Topics: Animals; Cementogenesis; Dental Cementum; Mice; Osteogenesis; Periodontal Ligament; X-Ray Microtomography
PubMed: 34009051
DOI: 10.1177/00220345211012386