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Objective: Calcified carotid artery atheroma (CCAA) can be identified incidentally on standard dental panoramic radiographs (DPRs). We sought to (1) determine the prevalence of CCAA on DPRs in a general dental population and (2) establish the proportion of patients in whom this would represent a new statin-indicated condition. Methods: We identified patients aged ≥30 with DPRs from 2019 to 2021 from the University of British Columbia Dental Clinic. Patient charts were reviewed for use of lipid-lowering therapies (LLT) and existing statin-indicated conditions. DPRs for each patient were evaluated for the presence and characteristics of CCAA. Results: Of 921 patients with a DPR and documented medical history, 548 (59.5 %) were diagnostic for evaluation of CCAA. Although 116/548 (21.2 %) of these patients had evidence of CCAA, only 25.9 % (30/116) were already on LLT; another 20.7 % (24/116) of patients with CCAA had a pre-existing statin-indicated condition but were not on LLT. Therefore, in 53.4 % (62/116) of patients with CCAA-positive DPRs, this constituted a new diagnosis of atherosclerosis not yet treated with LLT, representing 6.7 % (62/921) of the clinic population and 11.3 % of individuals with DPRs of diagnostic quality (62/548). Dyslipidemia, hypertension, coronary artery disease, diabetes, atrial fibrillation, stroke/transient ischemic attack, older age, and male sex were all found to be significant predictors of CCAA. Conclusion: CCAA is a common finding among patients with DPRs and in over half of cases, the presence of CCAA represents a new diagnosis of atherosclerosis. The high prevalence of new, untreated atherosclerosis in this population indicates an opportunity for risk factor modification and collaboration between dentists and physicians to optimize patient care.
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OBJECTIVE: To investigate how delayed blood centrifugation affects the composition of the resultant platelet rich fibrin membrane (PRF, a concentrated growth factor preparation) and its biological effects towards gingival fibroblasts. MATERIALS AND METHODS: Blood samples were collected from 18 healthy individuals and centrifuged immediately (T-0), or after a 1-6-minute delay (T-1-6, respectively), to generate PRF. Each PRF membrane was weighed. T-0 and T-6 membranes were incubated for 48 h in cell culture medium at 37 °C to create PRF "releasates" (soluble factors released from the PRF). Human gingival fibroblasts were incubated for 48 h with or without the releasates, followed by RNA isolation and real-time polymerase chain reaction to measure expression of select genes associated with granulation tissue formation, angiogenesis and wound contraction. Additional T-0 and T-6 membranes were used for visualization of leucocyte nuclei and platelets by immunostaining. RESULTS: Immediate centrifugation (T-0) resulted in the largest membranes, T-6 membranes being on average 29% smaller. Leucocytes and platelets were significantly more abundant in T-0 than in T-6 samples. Majority of the fibroblast genes studied were consistently either upregulated or downregulated by the T-0 PRF releasates. However, centrifugation after a 6-minute delay significantly weakened the fibroblast responses. CONCLUSIONS: Delayed centrifugation resulted in smaller PRF membranes with fewer leucocytes and platelets and also significantly reduced on the expression of a set of healing-related gingival fibroblast genes. CLINICAL RELEVANCE: The higher expression of wound healing-related genes in gingival fibroblasts by the immediately-centrifuged PRF membranes may increase their biological properties in clinical use.
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Fibrina Rica en Plaquetas , Humanos , Plaquetas , Cicatrización de Heridas , Leucocitos , Centrifugación/métodosRESUMEN
Periodontal disease (PD) can be prevented by local or systemic application of epidermal growth factor receptor inhibitors (EGFRIs) that stabilize αvß6 integrin levels in the periodontal tissue, leading to an increase in the expression of anti-inflammatory cytokines, such as transforming growth factor-ß1. Systemic EGFRIs have side effects and, therefore, local treatment of PD applied into the periodontal pockets would be preferrable. Thus, we have developed slow-release three-layered microparticles of gefitinib, a commercially available EGFRI. A combination of different polymers [cellulose acetate butyrate (CAB), Poly (D, L-lactide-co-glycolide) (PLGA) and ethyl cellulose (EC)] and sugars [D-mannose, D-mannitol and D-(+)-trehalose dihydrate] were used for the encapsulation. The optimal formulation was composed of CAB, EC, PLGA, mannose and gefitinib (0.59, 0.24, 0.09, 1, and 0.005 mg/ml, respectively; labeled CEP-gef), and created microparticles of 5.7 ± 2.3 µm in diameter, encapsulation efficiency of 99.98%, and a release rate of more than 300 h. A suspension of this microparticle formulation blocked EGFR phosphorylation and restored αvß6 integrin levels in oral epithelial cells, while the respective control microparticles showed no effect.
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Enfermedades Periodontales , Ácido Poliglicólico , Humanos , Copolímero de Ácido Poliláctico-Ácido Poliglicólico , Gefitinib , Ácido Láctico , Enfermedades Periodontales/tratamiento farmacológico , Microesferas , Tamaño de la PartículaRESUMEN
OBJECTIVES: Peri-implantitis (PI) is caused by bacteria in the peri-implant space but the consensus on microbial profile is still lacking. Current microbial sampling of PI lesions has largely focused on analyzing bacterial species that have been shed from the implant surface and captured in the pocket fluid. The purpose of the present study was to investigate the morphotypes of bacteria in biofilm covering the implant threads and explore whether certain morphotypes were associated with PI. METHODS: Fourteen failed implants were removed and instantly processed for scanning electron microscope analysis. The implants were imaged at three equally divided sub-crestal levels of the exposed area. Bacterial morphotypes were identified and quantified by three examiners. Mobility and years in function were correlated to the presence of different morphotypes. RESULTS: The implants demonstrated the presence of variable bacterial morphotypes that did not correlate to disease progression in our study. Some implants were dominated by filaments and others showed the presence of combinations of cocci/rods or spirilles/spirochetes. In general, all implants showed variable morphologic biofilm composition. However, individual implants tended to have similar composition throughout the entire implant. Rods and filaments were dominant morphotypes throughout the surfaces and cocci showed increased presence toward the apical third. There were some differences in the biofilm morphology with mobility and time in function. CONCLUSIONS: The profiles of bacterial biofilm morphotypes in failing implants with similar clinical presentations were highly variable. While there were significant differences between implants, similar morphotypes in individual implants were often found throughout the entire surface.
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Periimplantitis , Humanos , Microscopía Electrónica de Rastreo , Electrones , Bacterias , BiopelículasRESUMEN
Standard cell cultures are performed in aqueous media with a low macromolecule concentration compared to tissue microenvironment. In macromolecular crowding (MMC) experiments, synthetic polymeric crowders are added into cell culture media to better mimic macromolecule concentrations found in vivo. However, their effect on cultured cells is incompletely understood and appears context-dependent. Here we show using human gingival fibroblasts, a cell type associated with fast and scarless wound healing, that MMC (standard medium supplemented with Ficoll 70/400) potently modulates fibroblast phenotype and extracellular matrix (ECM) composition compared to standard culture media (nMMC) over time. MMC significantly reduced cell numbers, but increased accumulation of collagen I, cellular fibronectin, and tenascin C, while suppressing level of SPARC (Secreted Protein Acidic and Cysteine Rich). Out of the 75 wound healing and ECM related genes studied, MMC significantly modulated expression of 25 genes compared to nMMC condition. MMC also suppressed myofibroblast markers and promoted deposition of basement membrane molecules collagen IV, laminin 1, and expression of LAMB3 (Laminin Subunit Beta 3) gene. In cell-derived matrices produced by a novel decellularization protocol, the altered molecular composition of MMC matrices was replicated. Thus, MMC may improve cell culture models for research and provide novel approaches for regenerative therapy.
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Colágeno Tipo I , Matriz Extracelular , Humanos , Colágeno Tipo I/metabolismo , Matriz Extracelular/metabolismo , Células Cultivadas , Fibroblastos/metabolismo , Sustancias Macromoleculares/metabolismo , Medios de Cultivo/farmacología , Medios de Cultivo/metabolismo , Expresión Génica , Fibronectinas/metabolismoRESUMEN
Soft tissue calcification occurs in many parts of the body, including the gingival tissue. Epithelial cell-derived MVs can control many functions in fibroblasts but their role in regulating mineralization has not been explored. We hypothesized that microvesicles (MVs) derived from gingival epithelial cells could regulate calcification of gingival fibroblast cultures in osteogenic environment. Human gingival fibroblasts (HGFs) were cultured in osteogenic differentiation medium with or without human gingival epithelial cell-derived MV stimulation. Mineralization of the cultures, localization of the MVs and mineral deposits in the HGF cultures were assessed. Gene expression changes associated with MV exposure were analyzed using gene expression profiling and real-time qPCR. Within a week of exposure, epithelial MVs stimulated robust mineralization of HGF cultures that was further enhanced by four weeks. The MVs taken up by the HGF's did not calcify themselves but induced intracellular accumulation of minerals. HGF gene expression profiling after short exposure to MVs demonstrated relative dominance of inflammation-related genes that showed increases in gene expression. In later cultures, OSX, BSP and MMPs were significantly upregulated by the MVs. These results suggest for the first time that epithelial cells maybe associated with the ectopic mineralization process often observed in the soft tissues.
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Calcinosis , Osteogénesis , Calcinosis/metabolismo , Diferenciación Celular , Células Cultivadas , Células Epiteliales/metabolismo , Fibroblastos/metabolismo , Encía , HumanosRESUMEN
In periodontal disease (PD), bacterial biofilms suppress ß6 integrin expression transforming growth factor-ß1 signaling, resulting in gingival inflammation and bone loss. ß6 integrin-null (Itgb6-/- ) mice develop spontaneous PD. The aim of this study was to unravel potential differences in oral microbiome in wild-type (WT) and Itgb6-/- FVB mice. Mouse oral microbiome was analyzed from 3- and 6-month-old WT and Itgb6-/- . The periodontal inflammation and spontaneous bone loss were present in 3-month-old and advanced in 6-month-old Itgb6-/- mice. The observed amplicon sequence variants (ASVs) of alpha diversity showed close similarity in 3-month-old and 6-month-old Itgb6-/- mice. Chao1 and ACE methods revealed that the microbiome in Itgb6-/- mice showed less diversity compared to the WT. UniFrac Principal Coordinate analyses (PCoA) showed a clear spatial segregation and clustering between Itgb6-/- and WT mice in general, and between 3-month- and 6-month-old WT mice. Weighted PCoA showed the tight clustering and distinct separation of individual mouse samples within Itgb6-/- and WT. The most abundant microbial classes varied between the sample groups. However, the genus Aggregatibacter significantly increased in the 6-month-old Itgb6-/- mice. ß6 integrin-deficient mice develop periodontal inflammation that may relate to dysbiosis in the microbiome that further promotes the disease process.
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OBJECTIVES: Decontamination of biofilm-colonized rough implant surfaces remains challenging. We investigated the effect of airflow with glycine powder (AFG) on decontamination of mature oral multispecies biofilm from a sandblasted and acid etched (SLA) titanium surface. MATERIALS AND METHODS: Subgingival dental plaque was cultured on SLA disks anaerobically for 21 days. AFG with various settings and distances was applied directly on the disks with or without previous rinse of 0.9% NaCl. The specimens were then analyzed through scanning electron microscope and remaining bacteria on the implant surface were quantified and statistically compared. RESULTS: Mature oral biofilm with cocci and rods as major morphotypes, as well as spiral- and filamentous-shaped organisms, was formed on the untreated disks. Saline rinsing removed the thick biofilm layer but left numerous of coccoid bacteria in rough surface pits. AFG effectively removed most of the bacteria from the pits. Both 25% and 50% power settings were equally effective at 3-mm distance. With 50% power, AFG successfully removed bacteria at both 3- and 6-mm distance. When AFG was applied on native biofilm without prior rinsing with saline, it effectively removed the biofilm including bacteria in the pits. CONCLUSION: Application of AFG appears effective in removing bacteria from rough implant surfaces.
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Implantes Dentales , Biopelículas , Descontaminación , Implantes Dentales/microbiología , Glicina/farmacología , Propiedades de SuperficieRESUMEN
BACKGROUND: Decontamination of biofilm-infected rough implant surfaces is challenging. Platelet rich blood products have been shown to have anti-microbial properties against periodontal pathogens. Our aim was to investigate the effect of a potential biological implant surface disinfectant, leukocyte- and platelet-rich fibrin (L-PRF), on a mature oral multispecies biofilm on a rough titanium surface. METHODS: Sandblasted, large grit, acid-etched (SLA) titanium disks were inoculated with subgingival dental plaque and cultured anaerobically for 21 days. The L-PRF membranes were collected from 12 donors in three trials (four donors in each trial). The disks were rinsed with 0.9% NaCl and exposed to the cell-rich portion of the L-PRF membranes for 48 hours followed by scanning electron microscope (SEM) analysis immediately or after rinsing with 0.9% NaCl prior to fixation. The presence of platelet factor-4 in the rinse samples was analyzed by Western blotting. Remaining bacteria were quantified from SEM images of the implant surfaces and their numbers statistically compared. RESULTS: The L-PRF-treated samples without rinsing displayed numerous cells with multiple pseudopodia in immediate contact with bacteria that appeared perforated and increased in size. The cells were identified as platelets based on morphological criteria and by positive reaction for platelet factor-4 by Western blotting. After post-treatment rinsing, the L-PRF-treated disks displayed a significant reduction in bacterial counts (in average 92% reduction). CONCLUSION: Application of L-PRF significantly reduced bacterial counts on contaminated SLA titanium surface, most likely through anti-microbial action by platelets.
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Fibrina Rica en Plaquetas , Biopelículas , Descontaminación , Leucocitos , Propiedades de Superficie , TitanioRESUMEN
BACKGROUND: Leucocyte- and platelet-rich fibrin (L-PRF) is a blood-derived biomaterial rich in leucocytes and platelets embedded in a high-density fibrin network that can be compressed into a membrane and used in surgical applications to stimulate tissue regeneration and wound healing, especially in oral cavity. This study aimed to determine the combined effects of the growth factors and cells present in L-PRF on fibroblasts that directly face the L-PRF membranes placed during surgical procedures. METHODS: The effect of L-PRF from six donors on the expression of 84 key wound healing genes in normal human gingival fibroblasts was tested by RT-qPCR. RESULTS: L-PRF significantly regulated the expression of 33 fibroblast genes (39%), including interleukins, myofibroblast-, extracellular matrix- and angiogenesis-associated genes, and matrix metalloproteinase-1 and -3. L-PRF regulated fibroblast gene expression both time- and dose-dependently, and the effects were mediated by mitogen-activated protein kinases ERK1/2, JNK and p38. L-PRF also stimulated fibroblast wound closure and promoted the ability of fibroblasts to induce endothelial tube formation. L-PRF-induced gene expression changes in fibroblast were similar to those observed in early human and pig wounds. CONCLUSIONS: This study provides new insights into the biological mechanism by which L-PRF regulates key gingival fibroblast functions important in wound healing.
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Fibrina Rica en Plaquetas , Animales , Fibroblastos , Encía , Humanos , Leucocitos , Porcinos , Cicatrización de HeridasRESUMEN
In periodontal disease (PD), bacterial biofilms cause gingival inflammation, leading to bone loss. In healthy individuals, αvß6 integrin in junctional epithelium maintains anti-inflammatory transforming growth factor-ß1 (TGF-ß1) signaling, whereas its expression is lost in individuals with PD. Bacterial biofilms suppress ß6 integrin expression in cultured gingival epithelial cells (GECs) by attenuating TGF-ß1 signaling, leading to an enhanced pro-inflammatory response. In the present study, we show that GEC exposure to biofilms induced activation of mitogen-activated protein kinases and epidermal growth factor receptor (EGFR). Inhibition of EGFR and ERK stunted both the biofilm-induced ITGB6 suppression and IL1B stimulation. Furthermore, biofilm induced the expression of endogenous EGFR ligands that suppressed ITGB6 and stimulated IL1B expression, indicating that the effects of the biofilm were mediated by autocrine EGFR signaling. Biofilm and EGFR ligands induced inhibitory phosphorylation of the TGF-ß1 signaling mediator Smad3 at S208. Overexpression of a phosphorylation-defective mutant of Smad3 (S208A) reduced the ß6 integrin suppression. Furthermore, inhibition of EGFR signaling significantly reduced bone loss and inflammation in an experimental PD model. Thus, EGFR inhibition may provide a target for clinical therapies to prevent inflammation and bone loss in PD.
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Pérdida de Hueso Alveolar/patología , Antígenos de Neoplasias/genética , Biopelículas , Células Epiteliales/metabolismo , Receptores ErbB/metabolismo , Encía/citología , Integrinas/genética , Animales , Células Cultivadas , Células Epiteliales/microbiología , Encía/microbiología , Humanos , Mediadores de Inflamación/metabolismo , Ratones , Enfermedades Periodontales/genética , Enfermedades Periodontales/metabolismo , Fosforilación , Transducción de Señal , Factor de Crecimiento Transformador beta1/metabolismoAsunto(s)
Enfermedades de las Encías/diagnóstico , Granuloma Piogénico/diagnóstico , Complicaciones del Embarazo/diagnóstico , Adulto , Femenino , Enfermedades de las Encías/etiología , Enfermedades de las Encías/patología , Enfermedades de las Encías/cirugía , Granuloma Piogénico/etiología , Granuloma Piogénico/patología , Granuloma Piogénico/cirugía , Humanos , Higiene Bucal/efectos adversos , Embarazo , Complicaciones del Embarazo/etiología , Complicaciones del Embarazo/patología , Complicaciones del Embarazo/cirugía , Progesterona/efectos adversos , Progestinas/efectos adversosRESUMEN
Epithelial αvß6 integrin participates in immune surveillance in many organs, including the gastrointestinal track. Expression of αvß6 integrin is reduced in the junctional epithelium of the gingiva in periodontal diseases, and mutations in the ITGB6 gene are associated with these diseases in humans and mice. The aim of this study was to unravel potential differences in the inflammatory responses in the periodontal tissues of FVB wild-type (WT) and ß6 integrin-null (Itgb6-/-) mice, using a ligature-induced periodontitis model and assessing inflammation, bone loss and expression profiles of 34 genes associated with periodontal disease. Using micro-CT and histology, we demonstrated more advanced inflammation and bone loss in the control and ligatured Itgb6-/- mice compared to the WT animals. Neutrophil and macrophage marker genes were significantly upregulated by ligation in both WT and Itgb6-/- mice while the expression of T-cell and B-cell markers was downregulated, suggesting acute-type of inflammation. Expression of inflammasome NLRP3-related genes Nlpr3 and Il1b was also significantly increased in both groups. However, the expression of Il18 was significantly lower in non-ligatured Itgb6-/- mice than in the WT mice and was further downregulated in both groups by the ligatures. IL-18 mediates many effects of the AIM2 inflammasome, including regulation of the microbiome. Interestingly, expression of Aim2 was significantly lower in both control and ligatured Itgb6-/- mice than in WT animals. Overall, ligature-induced periodontitis was associated with increased expression of pro-inflammatory cytokines, chemokines and osteoclastogenic regulatory molecules. Another significant difference between the Itgb6-/- and WT mice was that mRNA expression of the anti-inflammatory cytokine IL-10 was increased in ligatured WT mice but reduced in the Itgb6-/- mice. In conclusion, αvß6 integrin in junctional epithelium of the gingiva appears to positively regulate the expression of the AIM2 inflammasome and anti-inflammatory IL-10, thus providing protection against periodontal inflammation.
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Citocinas/genética , Perfilación de la Expresión Génica , Inflamasomas/genética , Cadenas beta de Integrinas/metabolismo , Periodontitis/genética , Proceso Alveolar/patología , Animales , Antígenos de Neoplasias/metabolismo , Biomarcadores/metabolismo , Resorción Ósea/patología , Quimiocina CCL3/metabolismo , Citocinas/metabolismo , Regulación de la Expresión Génica , Inflamasomas/metabolismo , Integrinas/metabolismo , Interleucina-10/metabolismo , Ratones Noqueados , Periodoncio/patología , Proteína smad3/metabolismoRESUMEN
Integrins are cell surface receptors that traditionally mediate cell-to-extracellular matrix and cell-to-cell adhesion. They can, however, also bind a large repertoire of other molecules. Integrin αvß6 is exclusively expressed in epithelial cells where it can, for example, serve as a fibronectin receptor. However, its hallmark function is to activate transforming growth factor-ß1 (TGF-ß1) to modulate innate immune surveillance in lungs and skin and along the gastrointestinal tract, and to maintain epithelial stem cell quiescence. The loss of αvß6 integrin function in mice and humans leads to an altered immune response in lungs and skin, amelogenesis imperfecta, periodontal disease and, in some cases, alopecia. Elevated αvß6 integrin expression and aberrant TGF-ß1 activation and function are associated with organ fibrosis and cancer. Therefore, αvß6 integrin serves as an attractive target for cancer imaging and for fibrosis and cancer therapy.
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Antígenos de Neoplasias/química , Antígenos de Neoplasias/metabolismo , Fibrosis/fisiopatología , Integrinas/química , Integrinas/metabolismo , Neoplasias/fisiopatología , Animales , HumanosRESUMEN
Fibroblasts are the most abundant connective tissue cells and play an important role in wound healing. It is possible that faster and scarless wound healing in oral mucosal gingiva relative to skin may relate to the distinct phenotype of the fibroblasts residing in these tissues. Connexin 43 (Cx43) is the most ubiquitous Cx in skin (SFBLs) and gingival fibroblasts (GFBLs), and assembles into hemichannels (HCs) and gap junctions (GJs) on the cell membrane. We hypothesized that SFBLs and GFBLs display distinct expression or function of Cx43, and that this may partly underlie the different wound healing outcomes in skin and gingiva. Here we show that Cx43 distinctly formed Cx43 GJs and HCs in human skin and gingiva in vivo. However, in SFBLs, in contrast to GFBLs, only a small proportion of total Cx43 assembled into HC plaques. Using an in vivo-like 3D culture model, we further show that the GJ, HC, and channel-independent functions of Cx43 distinctly regulated wound healing-related gene expression in GFBLs and SFBLs. Therefore, the distinct wound healing outcomes in skin and gingiva may partly relate to the inherently different assembly and function of Cx43 in the resident fibroblasts.
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Conexina 43/metabolismo , Fibroblastos/metabolismo , Regulación de la Expresión Génica , Encía/metabolismo , Piel/metabolismo , Cicatrización de Heridas/genética , Adulto , Animales , Células Cultivadas , Femenino , Uniones Comunicantes/metabolismo , Encía/citología , Humanos , Uniones Intercelulares/metabolismo , Masculino , Persona de Mediana Edad , Piel/citología , PorcinosRESUMEN
INTRODUCTION: To evaluate risk indicators associated with implant failure and relationship between bone levels and soft-tissue health of anodized implants placed in private practice. MATERIAL AND METHODS: Partially or completely edentulous patients who received an anodized implant between 2003 and 2013 were included. Univariate and multivariate analysis was used to identify the relationship between study variables and implant failure. Mean marginal bone level changes (MBLΔ) were assessed using periapical radiographs. Periimplant soft tissue was evaluated using a modified bleeding index (implant mucosal index, IMI). RESULTS: A total of 1087 implants placed in 414 patients were followed for 3.9 ± 2.7 years. The cumulative implant survival rate after 10 years of function was 97.0%. Shorter (P = 0.0068) and maxillary implants (P = 0.0314) were associated with lower implant survival rate. Mean MBL decreased from -0.16 ± 0.43 mm at baseline to -0.53 ± 0.53 mm 8 to 10 years later. Implants with healthier mucosa were associated with less bone loss. CONCLUSIONS: Implants with an anodized surface showed a high long-term survival rate in a daily practice. Longer implants and implants placed in the mandible were associated with greater survival. Immediate loading and tapered design did not affect implant survival. Profuse multipoint bleeding and suppuration on recall were associated with greater bone loss.
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Bone is a composite material composed of collagen and calcium phosphate (CaP) mineral. The collagen gives bone its flexibility while the inorganic material gives bone its resilience. The CaP in bone is similar in composition and structure to the mineral hydroxyapatite (HA) and is bioactive, osteoinductive and osteoconductive. Therefore synthetic versions of bone apatite (BA) have been developed to address the demand for autologous bone graft substitutes. Synthetic HA (s-HA) are stiff and strong, but brittle. These lack of physical attributes limit the use of synthetic apatites in situations where no physical loading of the apatite occurs. s-HA chemical properties differ from BA and thus change the physical and mechanical properties of the material. Consequently, s-HA is more chemically stable than BA and thus its resorption rate is slower than the rate of bone regeneration. One solution to this problem is to introduce a faster resorbing CaP, such as ß-tricalcium phosphate (ß-TCP), when synthesizing the material creating a biphasic (s-HA and ß-TCP) formulation of calcium phosphate (BCP). The focus of this review is to introduce the major differences between BCP and biological apatites and how material scientists have overcome the inadequacies of the synthetic counterparts. Examples of BCP performance in vitro and in vivo following structural and chemical modifications are provided as well as novel ultrastructural data. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 2493-2512, 2018.
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Regeneración Ósea/efectos de los fármacos , Huesos , Fosfatos de Calcio , Cerámica , Durapatita , Animales , Huesos/lesiones , Huesos/metabolismo , Huesos/patología , Fosfatos de Calcio/química , Fosfatos de Calcio/uso terapéutico , Cerámica/química , Cerámica/uso terapéutico , Durapatita/química , Durapatita/uso terapéutico , HumanosRESUMEN
Connexin 43 (Cx43) is the most ubiquitous connexin in various cells, and presents as hemichannels (HCs) and gap junctions (GJs) on the cell membrane. We have recently shown that Cx43 abundance was strongly reduced in fibroblasts of human gingival wounds, and blocking Cx43 function in cultured human gingival fibroblasts (GFBLs) strongly regulated the expression of wound healing-related genes. However, it is not known whether these responses involved Cx43 HCs or GJs. Here we show that Cx43 assembled into distinct GJ and HC plaques in GFBLs both in vivo and in vitro. Specific blockage of Cx43 HC function by TAT-Gap19, a Cx43 mimetic peptide, significantly upregulated the expression of several MMPs, TGF-ß signaling molecules, Tenascin-C, and VEGF-A, while pro-fibrotic molecules, including several extracellular matrix proteins and myofibroblast and cell contractility-related molecules, were significantly downregulated. These changes were linked with TAT-Gap19-induced suppression of ATP signaling and activation of the ERK1/2 signaling pathway. Collectively, our data suggest that reduced Cx43 HC function could promote fast and scarless gingival wound healing. Thus, selective suppression of Cx43 HCs may provide a novel target to modulate wound healing.
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Conexina 43/metabolismo , Fibroblastos/fisiología , Regulación de la Expresión Génica , Encía/citología , Cicatrización de Heridas/genética , Adenosina Trifosfato/metabolismo , Adulto , Ciclo Celular/genética , Células Cultivadas , Conexina 43/genética , Conexina 43/farmacología , Femenino , Fibroblastos/efectos de los fármacos , Uniones Comunicantes/metabolismo , Encía/lesiones , Humanos , Sistema de Señalización de MAP Quinasas/efectos de los fármacos , Masculino , Persona de Mediana Edad , Fragmentos de Péptidos/farmacologíaRESUMEN
Periodontal diseases manifest by the formation of deep pockets between the gingiva and teeth where multispecies bacterial biofilms flourish, causing inflammation and bone loss. Epithelial cell receptor αvß6 integrin that regulates inflammation by activating the anti-inflammatory cytokine transforming growth factor-ß1, is highly expressed in healthy junctional epithelium that connects the gingiva to the tooth enamel. However, its expression is attenuated in human periodontal disease. Moreover, Itgb6 -/- mice display increased periodontal inflammation compared to wild-type mice. We hypothesized that bacterial biofilms present in the periodontal pockets suppress αvß6 integrin levels in periodontal disease and that this change aggravates inflammation. To this end, we generated three-week-old multi-species oral biofilms in vitro and treated cultured gingival epithelial cells (GECs) with their extracts. The biofilm extracts caused suppression of ß6 integrin expression and upregulation of pro-inflammatory cytokines, including interleukin-1ß and -6. Furthermore, GECs with ß6 integrin siRNA knockdown showed increased interleukin-1ß expression, indicating that αvß6 integrin-deficiency is associated with pro-inflammatory cytokine responsiveness. FSL-1, a synthetic bacterial lipopeptide, also suppressed ß6 integrin expression in GECs. Therefore, biofilm components, including lipopeptides, may downregulate αvß6 integrin expression in the pocket epithelium and thus promote epithelial cell-driven pro-inflammatory response in periodontal disease.
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Antígenos de Neoplasias/genética , Biopelículas , Células Epiteliales/metabolismo , Células Epiteliales/microbiología , Encía/citología , Encía/microbiología , Integrinas/genética , Microbiota , Animales , Citocinas/metabolismo , Placa Dental/microbiología , Diglicéridos/metabolismo , Expresión Génica , Técnicas de Inactivación de Genes , Humanos , Mediadores de Inflamación/metabolismo , Queratinocitos/metabolismo , Ratones , Oligopéptidos/metabolismo , Enfermedades Periodontales/genética , Enfermedades Periodontales/metabolismo , Enfermedades Periodontales/patología , Transducción de Señal , Factor de Crecimiento Transformador beta1/metabolismoRESUMEN
Compared to skin, wound healing in oral mucosa is faster and produces less scarring, but the mechanisms involved are incompletely understood. Studies in mice have linked high expression of CD26 to a profibrotic fibroblast phenotype, but this has not been tested in models more relevant for humans. We hypothesized that CD26 is highly expressed by human skin fibroblasts (SFBLs), and this associates with a profibrotic phenotype distinct from gingival fibroblasts (GFBLs). We compared CD26 expression in human gingiva and skin and in gingival and hypertrophic-like scar-forming skin wound healing in a pig model, and used three-dimensional cultures of human GFBLs and SFBLs. In both humans and pigs, nonwounded skin contained abundantly CD26-positive fibroblasts, whereas in gingiva they were rare. During skin wound healing, CD26-positive cells accumulated over time and persisted in forming hypertrophic-like scars, whereas few CD26-positive cells were present in the regenerated gingival wounds. Cultured human SFBLs displayed significantly higher levels of CD26 than GFBLs. This was associated with an increased expression of profibrotic genes and transforming growth factor-ß signaling in SFBLs. The profibrotic phenotype of SFBLs partially depended on expression of CD26, but was independent of its catalytic activity. Thus, a CD26-positive fibroblast population that is abundant in human skin but not in gingiva may drive the profibrotic response leading to excessive scarring.