Publications by authors named "Rolando Vernal"

62 Publications

Premature Senescence of T-cells Favors Bone Loss During Osteolytic Diseases. A New Concern in the Osteoimmunology Arena.

Aging Dis 2021 Aug 1;12(5):1150-1161. Epub 2021 Aug 1.

1Periodontal Biology Laboratory, Faculty of Dentistry, Universidad de Chile, Santiago, Chile.

Cellular senescence is a biological process triggered in response to time-accumulated DNA damage, which prioritizes cell survival over cell function. Particularly, senescent T lymphocytes can be generated prematurely during chronic inflammatory diseases regardless of chronological aging. These senescent T lymphocytes are characterized by the loss of CD28 expression, a co-stimulatory receptor that mediates antigen presentation and effective T-cell activation. An increased number of premature senescent CD4CD28 T lymphocytes has been frequently observed in osteolytic diseases, including rheumatoid arthritis, juvenile idiopathic arthritis, ankylosing spondylitis, osteopenia, osteoporosis, and osteomyelitis. Indeed, CD4CD28 T lymphocytes produce higher levels of osteoclastogenic molecular mediators directly related to pathologic bone loss, such as tumor necrosis factor (TNF)-α, interleukin (IL)-17A, and receptor-activator of nuclear factor κB ligand (RANKL), as compared with regular CD4CD28 T lymphocytes. In addition, premature senescent CD8CD28 T lymphocytes have been negatively associated with bone healing and regeneration by inhibiting osteoblast differentiation and mesenchymal stromal cell survival. Therefore, accumulated evidence supports the role of senescent T lymphocytes in osteoimmunology. Moreover, premature senescence of T-cells seems to be associated with the functional imbalance between the osteolytic T-helper type-17 (Th17) and bone protective T regulatory (Treg) lymphocytes, as well as the phenotypic instability of Treg lymphocytes responsible for its trans-differentiation into RANKL-producing exFoxp3Th17 cells, a key cellular phenomenon directly related to bone loss. Herein, we present a framework for the understanding of the pathogenic characteristics of T lymphocytes with a premature senescent phenotype; and particularly, we revise and discuss their role in the osteoimmunology of osteolytic diseases.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.14336/AD.2021.0110DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8279535PMC
August 2021

Humanized Mouse Models for the Study of Periodontitis: An Opportunity to Elucidate Unresolved Aspects of Its Immunopathogenesis and Analyze New Immunotherapeutic Strategies.

Front Immunol 2021 17;12:663328. Epub 2021 Jun 17.

Periodontal Biology Laboratory, Faculty of Dentistry, Universidad de Chile, Santiago, Chile.

Periodontitis is an oral inflammatory disease in which the polymicrobial synergy and dysbiosis of the subgingival microbiota trigger a deregulated host immune response, that leads to the breakdown of tooth-supporting tissues and finally tooth loss. Periodontitis is characterized by the increased pathogenic activity of T helper type 17 (Th17) lymphocytes and defective immunoregulation mediated by phenotypically unstable T regulatory (Treg), lymphocytes, incapable of resolving the bone-resorbing inflammatory milieu. In this context, the complexity of the immune response orchestrated against the microbial challenge during periodontitis has made the study of its pathogenesis and therapy difficult and limited. Indeed, the ethical limitations that accompany human studies can lead to an insufficient etiopathogenic understanding of the disease and consequently, biased treatment decision-making. Alternatively, animal models allow us to manage these difficulties and give us the opportunity to partially emulate the etiopathogenesis of periodontitis by inoculating periodontopathogenic bacteria or by placing bacteria-accumulating ligatures around the teeth; however, these models still have limited translational application in humans. Accordingly, humanized animal models are able to emulate human-like complex networks of immune responses by engrafting human cells or tissues into specific strains of immunodeficient mice. Their characteristics enable a viable time window for the study of the establishment of a specific human immune response pattern in an setting and could be exploited for a wider study of the etiopathogenesis and/or treatment of periodontitis. For instance, the antigen-specific response of human dendritic cells against the periodontopathogen favoring the Th17/Treg response has already been tested in humanized mice models. Hypothetically, the proper emulation of periodontal dysbiosis in a humanized animal could give insights into the subtle molecular characteristics of a human-like local and systemic immune response during periodontitis and support the design of novel immunotherapeutic strategies. Therefore, the aims of this review are: To elucidate how the microbiota-elicited immunopathogenesis of periodontitis can be potentially emulated in humanized mouse models, to highlight their advantages and limitations in comparison with the already available experimental periodontitis non-humanized animal models, and to discuss the potential translational application of using these models for periodontitis immunotherapeutics.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3389/fimmu.2021.663328DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8248545PMC
June 2021

The influence of flap design on patients' experiencing pain, swelling, and trismus after mandibular third molar surgery: a scoping systematic review.

J Appl Oral Sci 2021 4;29:e20200932. Epub 2021 Jun 4.

Campania University Luigi Vanvitelli, Multidisciplinary Department of Medical, Surgical and Dental sciences, Naples, Italy.

Third molar removal surgery usually comes accompanied by postoperative discomfort, which could be influenced by the surgical approach chosen. This scoping systematic review aimed at compiling the available evidence focused on the influence of flap design, including envelope flap (EF), triangular flap (TF), and modified triangular flap (MTF), on postoperative pain, swelling, and trismus, as primary outcome measures, and any result mentioning healing promotion or delay, as secondary outcome measure, after mandibular third molar extraction surgery. An electronic search, complemented by a manual search, of articles published from 1999 to 2020 was conducted in the Medline (PubMed), EMBASE and Web of Science databases including human randomized controlled trials, prospective, and retrospective studies with at least 15 patients. The risk of bias of the included studies was assessed either with the Cochrane's Risk of Bias tool or with the Newcastle-Ottawa scale. Every step of the review was performed independently and in duplicate. The initial electronic search recovered 2102 articles. After applying the inclusion criteria, 12 articles were included. For patient's perceived postoperative pain, TF and MTF frequently reported better results than EF. For swelling, the literature is divided, despite a trend favoring EF. For trismus, data showed that its occurrence is mostly associated with the duration of the surgery rather than with the chosen flap. For healing, the limited data is inconclusive. Finally, randomized studies showed a high risk of bias, whereas nonrandomized studies were mostly of good quality and low risk of bias. Although there was no clear consensus regarding the influence of different flap designs for third mandibular molar extraction on postoperative clinical morbidities; the surgeon's experience, estimated surgical difficulty, molar position and orientation, and surg ery duration should be considered when choosing among the different flap designs.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1590/1678-7757-2020-0932DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8232931PMC
June 2021

RvE1 Impacts the Gingival Inflammatory Infiltrate by Inhibiting the T Cell Response in Experimental Periodontitis.

Front Immunol 2021 3;12:664756. Epub 2021 May 3.

Forsyth Institute, Cambridge, MA, United States.

Periodontitis is a chronic inflammatory disease associated with the formation of dysbiotic plaque biofilms and characterized by the progressive destruction of the alveolar bone. The transition from health to disease is characterized by a shift in periodontal immune cell composition, from mostly innate (neutrophils) to adaptive (T lymphocytes) immune responses. Resolvin E1 (RvE1) is a specialized pro-resolution mediator (SPMs), produced in response to inflammation, to enhance its resolution. Previous studies have indicated the therapeutic potential of RvE1 in periodontal disease; however, the impact of RvE1 in the microbial-elicited osteoclastogenic immune response remains uncharacterized . In the present study, we studied the impact of RvE1 on the gingival inflammatory infiltrate formation during periodontitis in a mouse model. First, we characterized the temporal-dependent changes of the main immune cells infiltrating the gingiva by flow cytometry. Then, we evaluated the impact of early or delayed RvE1 administration on the gingival immune infiltration and cervical lymph nodes composition. We observed a consistent inhibitory outcome on T cells -particularly effector T cells- and a protective effect on regulatory T cells (Tregs). Our data further demonstrated the wide range of actions of RvE1, its preventive role in the establishment of the adaptive immune response during inflammation, and bone protective capacity.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3389/fimmu.2021.664756DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8126725PMC
May 2021

Patient satisfaction and survival of maxillary overdentures supported by four or six splinted implants: a systematic review with meta-analysis.

BMC Oral Health 2021 05 8;21(1):247. Epub 2021 May 8.

Periodontal Biology Laboratory, Faculty of Dentistry, Universidad de Chile, Santiago, Chile.

Background: Implant-supported overdentures offer enhanced mechanical properties, which lead to better patient satisfaction and survival rates than conventional dentures. However, it is unclear whether these satisfaction levels and survival rates depend on the number of implants supporting the overdenture. Therefore, this systematic review aimed to compare maxillary overdentures supported by four or six splinted implants in terms of patient satisfaction, implant survival, overdenture survival, and prosthodontic complications.

Methods: Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE (PubMed), and EMBASE databases were systematically searched and complemented by hand searching from 2000 to 2019, employing a combination of specific keywords. Studies comparing the use of four versus six implants for supporting overdentures with at least one-year of follow-up after prosthesis installation and including ten fully edentulous patients were included. The risk of bias (RoB) was analyzed with Cochrane's RoB 2 and Newcastle-Ottawa tools. Implants and prosthesis survival rates were analyzed by random-effects meta-analysis and expressed as risk ratios or risk differences, respectively, and by the non-parametric unpaired Fisher's test.

Results: A total of 15 from 1865 articles were included, and reported follow-up times after implant placement ranged from 1 to 10 years. Irrespective of the number of implants used, high scores were reported by all studies investigating patient satisfaction. Meta-analysis and non-parametric Fisher's test showed no statistical differences regarding the survival rate of implants (P = 0.34, P = 0.3) or overdentures (P = 0.74, P = 0.9) when using 4 versus 6 splinted implants to support overdentures, and no significant differences regarding prosthodontic complications were found between groups. Randomized studies presented high RoB and non-randomized studies presented acceptable quality.

Conclusions: Within the limits of this systematic review, we can conclude that the bar-supported overdenture on four implants is not inferior to the overdenture supported by six implants for rehabilitating the edentulous maxilla, in terms of patient satisfaction, survival rates of implants and overdentures, and prosthodontic complications.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/s12903-021-01572-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8106178PMC
May 2021

Levels of low-molecular-weight hyaluronan in periodontitis-treated patients and its immunostimulatory effects on CD4 T lymphocytes.

Clin Oral Investig 2021 Feb 5. Epub 2021 Feb 5.

Periodontal Biology Laboratory, Faculty of Dentistry, Universidad de Chile, Sergio Livingstone Pohlhammer 943, Independencia, 8380492, Santiago, Chile.

Objectives: During periodontitis, chronic inflammation triggers soft tissue breakdown, and hyaluronan is degraded into fragments of low molecular weight (LMW-HA). This investigation aimed to elucidate whether LMW-HA fragments with immunogenic potential on T lymphocytes remain in periodontal tissues after periodontal treatment.

Materials And Methods: GCF samples were obtained from 15 periodontitis-affected patients and the LMW-HA, RANKL, and OPG levels were analyzed before and after 6 months of periodontal treatment by ELISA. Eight healthy individuals were analyzed as controls. Besides, human T lymphocytes were purified, exposed to infected dendritic cells, and pulsed with LMW-HA. Non-treated T lymphocytes were used as control. The expression levels of the transcription factors and cytokines that determine the Th1, Th17, and Th22 lymphocyte differentiation and function were analyzed by RT-qPCR. Similarly, the expression levels of RANKL and CD44 were analyzed.

Results: In the GCF samples of periodontitis-affected patients, higher levels of LMW-HA were detected when compared with those of healthy individuals (52.1 ± 15.4 vs. 21.4 ± 12.2, p < 0.001), and these increased levels did not decrease after periodontal therapy (52.1 ± 15.4 vs. 45.7 ± 15.9, p = 0.158). Similarly, the RANKL levels and RANKL/OPG ratios did not change after periodontal therapy. Furthermore, in human T lymphocytes, LMW-HA induced higher expression levels of the Th1, Th17, and Th22-related transcription factors and cytokines, as well as CD44 and RANKL, as compared with non-treated cells.

Conclusions: In some patients, increased levels of LMW-HA persist in periodontal tissues after conventional periodontal therapy, and these remaining LMW-HA fragments with immunostimulatory potential could induce the polarization of a pathologic Th1/Th17/Th22-pattern of immune response on T lymphocytes.

Clinical Relevance: The persistence of increased levels of LMW-HA in periodontal tissues after periodontal therapy could favor the recurrence of the disease and further breakdown of periodontal supporting tissues.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s00784-021-03808-9DOI Listing
February 2021

Micro-tomographic characterization of the root and canal system morphology of mandibular first premolars in a Chilean population.

Sci Rep 2021 01 8;11(1):93. Epub 2021 Jan 8.

Periodontal Biology Laboratory, Faculty of Dentistry, Universidad de Chile, Santiago, Chile.

This study aimed to analyze the root anatomy and root canal system morphology of mandibular first premolars in a Chilean population. 186 teeth were scanned using micro-computed tomography and reconstructed three-dimensionally. The root canal system morphology was classified using both Vertucci's and Ahmed's criteria. The radicular grooves were categorized using the ASUDAS system, and the presence of Tomes' anomalous root was associated with Ahmed's score. A single root canal was identified in 65.05% of teeth, being configuration type I according to Vertucci's criteria and code MP according to Ahmed's criteria. Radicular grooves were observed in 39.25% of teeth. The ASUDAS scores for radicular grooves were 60.75%, 13.98%, 12.36%, 10.22%, 2.15%, and 0.54%, from grade 0 to grade 5, respectively. The presence of Tomes' anomalous root was identified only in teeth with multiple root canals, and it was more frequently associated with code MP of Ahmed's criteria. The root canal system morphology of mandibular first premolars showed a wide range of anatomical variations in the Chilean population. Teeth with multiple root canals had a higher incidence of radicular grooves, which were closely related to more complex internal anatomy. Only teeth with multiple root canals presented Tomes' anomalous root.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41598-020-80046-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7794380PMC
January 2021

Alzheimer's Disease-Like Pathology Triggered by in Wild Type Rats Is Serotype Dependent.

Front Immunol 2020 9;11:588036. Epub 2020 Nov 9.

Biomedical Neuroscience Institute, Faculty of Medicine, Universidad de Chile, Santiago, Chile.

Periodontal disease is a disease of tooth-supporting tissues. It is a chronic disease with inflammatory nature and infectious etiology produced by a dysbiotic subgingival microbiota that colonizes the gingivodental sulcus. Among several periodontal bacteria, () highlights as a keystone pathogen. Previous reports have implied that chronic inflammatory response and measurable bone resorption are observed in young mice, even after a short period of periodontal infection with , which has been considered as a suitable model of experimental periodontitis. Also, encapsulated strains are more virulent than capsular-defective mutants, causing an increased immune response, augmented osteoclastic activity, and accrued alveolar bone resorption in these rodent experimental models of periodontitis. Recently, has been associated with Alzheimer's disease (AD) pathogenesis, either by worsening brain pathology in AD-transgenic mice or by inducing memory impairment and age-dependent neuroinflammation middle-aged wild type animals. We hypothesized here that the more virulent encapsulated strains could trigger the appearance of brain AD-markers, neuroinflammation, and cognitive decline even in young rats subjected to a short periodontal infection exposure, due to their higher capacity of activating brain inflammatory responses. To test this hypothesis, we periodontally inoculated 4-week-old male Sprague-Dawley rats with K1, K2, or K4 serotypes and the K1-isogenic non-encapsulated mutant (GPA), used as a control. 45-days after periodontal inoculations with serotypes, rat´s spatial memory was evaluated for six consecutive days in the Oasis maze task. Following functional testing, the animals were sacrificed, and various tissues were removed to analyze alveolar bone resorption, cytokine production, and detect AD-specific biomarkers. Strikingly, only K1 or K2 -infected rats displayed memory deficits, increased alveolar bone resorption, pro-inflammatory cytokine production, changes in astrocytic morphology, increased Aβ1-42 levels, and Tau hyperphosphorylation in the hippocampus. None of these effects were observed in rats infected with the non-encapsulated bacterial strains. Based on these results, we propose that the bacterial virulence factors constituted by capsular polysaccharides play a central role in activating innate immunity and inflammation in the AD-like pathology triggered by in young rats subjected to an acute experimental infection episode.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3389/fimmu.2020.588036DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7680957PMC
July 2021

O-Polysaccharide Plays a Major Role on the Virulence and Immunostimulatory Potential of During Periodontal Infection.

Front Immunol 2020 30;11:591240. Epub 2020 Oct 30.

Periodontal Biology Laboratory, Faculty of Dentistry, Universidad de Chile, Santiago, Chile.

is a Gram-negative oral bacterium with high immunostimulatory and pathogenic potential involved in the onset and progression of periodontitis, a chronic disease characterized by aberrant immune responses followed by tooth-supporting bone resorption, which eventually leads to tooth loss. While several studies have provided evidence related to the virulence factors of involved in the host cell death and immune evasion, such as its most studied primate-specific virulence factor, leukotoxin, the role of specific lipopolysaccharide (LPS) domains remain poorly understood. Here, we analyzed the role of the immunodominant domain of the LPS of termed O-polysaccharide (O-PS), which differentiates the distinct bacterial serotypes based on its antigenicity. To determine the role of the O-PS in the immunogenicity and virulence of during periodontitis, we analyzed the and effect of an O-PS-defective transposon mutant serotype strain, characterized by the deletion of the gene encoding the α-L-rhamnose sugar biosynthetic enzyme. Induction of experimental periodontitis using the O-PS-defective mutant strain resulted in lower tooth-supporting bone resorption, infiltration of Th1, Th17, and Th22 lymphocytes, and expression of , , , , , and RANKL () in the periodontal lesions as compared with the wild-type strain. In addition, the O-PS-defective mutant strain led to impaired activation of antigen-presenting cells, with less expression of the co-stimulatory molecules CD40 and CD80 in B lymphocytes and dendritic cells, and downregulated expression of and in splenocytes. In conclusion, these data demonstrate that the O-PS from the serotype of plays a key role in the capacity of the bacterium to prime oral innate and adaptive immune responses, by triggering the Th1 and Th17-driven tooth-supporting bone resorption during periodontitis.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3389/fimmu.2020.591240DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7662473PMC
June 2021

Regulatory T cell phenotype and anti-osteoclastogenic function in experimental periodontitis.

Sci Rep 2020 11 4;10(1):19018. Epub 2020 Nov 4.

The Forsyth Institute, Cambridge, MA, USA.

The alveolar bone resorption is a distinctive feature of periodontitis progression and determinant for tooth loss. Regulatory T lymphocytes (Tregs) display immuno-suppressive mechanisms and tissue repairing functions, which are critical to support periodontal health. Tregs may become unstable and dysfunctional under inflammatory conditions, which can even accelerate tissue destruction. In this study, experimental periodontitis was associated with the progressive and increased presence of Th17 and Treg-related mediators in the gingiva (IL-6, IL-17A, IL-17F, RANKL, IL-10, TGF-β and GITR; P < 0.05), and the proliferation of both Treg and Th17 cells in cervical lymph nodes. Tregs from cervical lymph nodes had reduced Foxp3 expression (> 25% MFI loss) and increased IL-17A expression (> 15%), compared with Tregs from spleen and healthy controls. Tregs gene expression analysis showed a differential signature between health and disease, with increased expression of Th17-associated factors in periodontitis-derived Tregs. The ex vivo suppression capacity of Tregs on osteoclastic differentiation was significantly lower in Tregs obtained from periodontally diseased animals compared to controls (P < 0.05), as identified by the increased number of TRAP osteoclasts (P < 0.01) in the Tregs/pre-osteoclast co-cultures. Taken together, these results demonstrate that Tregs become phenotypically unstable and lose anti-osteoclastogenic properties during experimental periodontitis; thus, further promoting the Th17-driven bone loss.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41598-020-76038-wDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7642388PMC
November 2020

Overexpression of MMPs, cytokines, and RANKL/OPG in temporomandibular joint osteoarthritis and their association with joint pain, mouth opening, and bone degeneration: A preliminary report.

Oral Dis 2021 May 25;27(4):970-980. Epub 2020 Sep 25.

Periodontal Biology Laboratory, Faculty of Dentistry, Universidad de Chile, Santiago, Chile.

Objective: This study aimed to determine the expression of distinct matrix metalloproteinases, cytokines, and bone resorptive factors in temporomandibular joint osteoarthritis (TMJ-OA) patients and their association with joint pain, mouth opening, and subchondral bone degeneration.

Materials And Methods: Twelve patients affected with TMJ-OA (n = 5), disk displacement without reduction (DDWoR) (n = 3), or disk displacement with reduction (DDWR) (n = 4) were selected. Joint pain was quantified by using visual analog scale, mouth opening was quantified at the maximum pain-free aperture, and bone degeneration was quantified using joint imaging. Synovial fluid samples were collected and immediately processed for cell and synovial fluid recovering. From cells, the MMP-1, MMP-2, MMP-8, MMP-13, IL-6, IL-23, and TNF-α expression was quantified by qPCR. From synovial fluid, the RANKL and OPG levels were quantified by ELISA.

Results: Higher levels of MMP-1, MMP-8, MMP-13, IL-6, IL-23, TNF-α, and RANKL/OPG ratio were detected in TMJ-OA compared with DDWoR and DDWR patients (p < .05). Joint pain significantly correlated with TNF-α levels (r = .975, p = .029). Besides, imaging signs of bone degeneration significantly correlated with RANKL/OPG ratio (r = .949, p = .042). Conversely, mouth opening did not correlate with any of the analyzed mediators.

Conclusion: During TMJ-OA, a pathological response characterized by the overexpression of TNF-α and RANKL/OPG could be involved in joint pain and subchondral bone degeneration.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/odi.13623DOI Listing
May 2021

T regulatory cells-derived extracellular vesicles and their contribution to the generation of immune tolerance.

J Leukoc Biol 2020 09 12;108(3):813-824. Epub 2020 Jun 12.

Centro de Investigación Biomédica, Facultad de Medicina, Universidad de los Andes, Las Condes, Santiago, Chile.

T regulatory (Treg) cells have a major role in the maintenance of immune tolerance against self and foreign antigens through the control of harmful inflammation. Treg cells exert immunosuppressive function by several mechanisms, which can be distinguished as contact dependent or independent. Recently, the secretion of extracellular vesicles (EVs) by Treg cells has been reported as a novel suppressive mechanism capable of modulating immunity in a cell-contact independent and targeted manner, which has been identified in different pathologic scenarios. EVs are cell-derived membranous structures involved in physiologic and pathologic processes through protein, lipid, and genetic material exchange, which allow intercellular communication. In this review, we revise and discuss current knowledge on Treg cells-mediated immune tolerance giving special attention to the production and release of EVs. Multiple studies support that Treg cells-derived EVs represent a refined intercellular exchange device with the capacity of modulating immune responses, thus creating a tolerogenic microenvironment in a cell-free manner. The mechanisms proposed encompass miRNAs-induced gene silencing, the action of surface proteins and the transmission of enzymes. These observations gain relevance by the fact that Treg cells are susceptible to converting into effector T cells after exposition to inflammatory environments. Yet, in contrast to their cells of origin, EVs are unlikely to be modified under inflammatory conditions, highlighting the advantage of their use. Moreover, we speculate in the possibility that Treg cells may contribute to infectious tolerance via vesicle secretion, intervening with CD4 T cells differentiation and/or stability.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/JLB.3MR0420-533RRDOI Listing
September 2020

Boldine inhibits the alveolar bone resorption during ligature-induced periodontitis by modulating the Th17/Treg imbalance.

J Periodontol 2021 01 30;92(1):123-136. Epub 2020 Jun 30.

Periodontal Biology Laboratory, Faculty of Dentistry, Universidad de Chile, Santiago, Chile.

Background: During periodontitis, tooth-supporting alveolar bone is resorbed when there is an increased expression of the pro-osteolytic factor termed receptor activator of nuclear factor κB ligand (RANKL), which is responsible for osteoclast differentiation and activation. In periodontitis-affected tissues, the imbalance between T-helper type-17 (Th17) and T-regulatory (Treg) lymphocyte activity favors this RANKL overexpression. In this context, immunotherapeutic strategies aimed at modulating this Th17/Treg imbalance could eventually arrest the RANKL-mediated alveolar bone loss. Boldine has been reported to protect from pathological bone loss during rheumatoid arthritis and osteoporosis, whose pathogenesis is associated with a Th17/Treg imbalance. However, the effect of boldine on alveolar bone resorption during periodontitis has not been elucidated yet. This study aimed to determine whether boldine inhibits alveolar bone resorption by modulating the Th17/Treg imbalance during periodontitis.

Methods: Mice with ligature-induced periodontitis were orally treated with boldine (10/20/40 mg/kg) for 15 consecutive days. Non-treated periodontitis-affected mice and non-ligated mice were used as controls. Alveolar bone loss was analyzed by micro-computed tomography and scanning electron microscopy. Osteoclasts were quantified by histological identification of tartrate-resistant acid phosphatase-positive cells. Production of RANKL and its competitive antagonist osteoprotegerin (OPG) were analyzed by ELISA, quantitative polymerase chain reaction (qPCR), and immunohistochemistry. The Th17 and Treg responses were analyzed by quantifying the T-cell frequency and number by flow cytometry. Also, the expression of their signature transcription factors and cytokines were quantified by qPCR.

Results: Boldine inhibited the alveolar bone resorption. Consistently, boldine caused a decrease in the osteoclast number and RANKL/OPG ratio in periodontal lesions. Besides, boldine reduced the Th17-lymphocyte detection and response and increased the Treg-lymphocyte detection and response in periodontitis-affected tissues.

Conclusion: Boldine, administered orally, inhibited the alveolar bone resorption and modulated the Th17/Treg imbalance during experimental periodontitis.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/JPER.20-0055DOI Listing
January 2021

Macrophages skew towards M1 profile through reduced CD163 expression in symptomatic apical periodontitis.

Clin Oral Investig 2020 Dec 22;24(12):4571-4581. Epub 2020 May 22.

Laboratory of Periodontal Biology, Faculty of Dentistry, Universidad de Chile, Santiago, 8380000, Chile.

Objectives: To explore the macrophage profiles in symptomatic and asymptomatic forms of AP through phenotypic and functional analyses.

Material And Methods: Cross-sectional study. Apical tissue/lesion samples were collected from patients with clinical diagnosis of AAP (n = 51) or SAP (n = 45) and healthy periodontal ligament (HPL) from healthy patients as controls (n = 14), all with indication of tooth extraction. Samples were digested, cells were stained for CD14, M1 (CD64, CD80), and M2 (CD163, CD206) phenotypic surface markers and analyzed by flow cytometry. Functional cytokine profiles L-6, IL-12, TNF-α, IL-23 (M1), IL-10, and TGF-β (M2) were determined by qPCR.

Results: Higher macrophage M1/M2 ratio (CD64CD80/CD163CD206) along with lower CD163 mean fluorescence intensity (MFI) were found in SAP compared to AAP and controls (p < 0.05). IL-6, IL-12, TNF-α, IL-23 (M1), and IL-10 mRNA (M2) were upregulated, whereas TGF-β mRNA (M2) was downregulated in apical lesions compared to controls. Specifically, IL-6 and IL-23 (M1) were upregulated in SAP compared with AAP and controls (p < 0.05). The data were analyzed with Kruskal-Wallis test.

Conclusions: Macrophages exhibited a polarization switch towards M1 in AL. SAP exhibited a reduced M2 differentiation profile based on a reduction of CD163 expression levels in SAP over AAP. Specifically, IL-6 and IL-23 were augmented SAP over AAP, suggesting a role in the severity of apical lesions.

Clinical Relevance: Deciphering the macrophage polarization and functions in apical periodontitis can contribute to explain AP dynamics, its clinical presentation and systemic impact.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s00784-020-03324-2DOI Listing
December 2020

Induces Autophagy in Human Junctional Epithelium Keratinocytes.

Cells 2020 05 14;9(5). Epub 2020 May 14.

Center for Genomics and Bioinformatics, Faculty of Science, Universidad Mayor, Camino la Pirámide 5750, Huechuraba 8580745, Chile.

The adverse environmental conditions found in the periodontium during periodontitis pathogenesis stimulate local autophagy responses, mainly due to a continuous inflammatory response against the dysbiotic subgingival microbiome. The junctional epithelium represents the main site of the initial interaction between the host and the dysbiotic biofilm. Here, we investigated the role of autophagy in junctional epithelium keratinocytes (JEKs) in response to or its purified lipopolysaccharides (LPS). Immunofluorescence confocal analysis revealed an extensive nuclear translocation of transcription factor EB (TFEB) and consequently, an increase in autophagy markers and LC3-turnover assessed by immunoblotting and qRT-PCR. Correspondingly, challenged JEKs showed a punctuate cytosolic profile of LC3 protein contrasting with the diffuse distribution observed in untreated controls. Three-dimensional reconstructions of confocal images displayed a close association between intracellular bacteria and LC3-positive vesicles. Similarly, a close association between autophagic vesicles and the protein p62 was observed in challenged JEKs, indicating that p62 is the main adapter protein recruited during infection. Finally, the pharmacological inhibition of autophagy significantly increased the number of bacteria-infected cells as well as their death, similar to treatment with LPS. Our results indicate that infection induces autophagy in JEKs, and this homeostatic process has a cytoprotective effect on the host cells during the early stages of infection.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3390/cells9051221DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7290389PMC
May 2020

Periodontal disease and its impact on general health in Latin America. Section II: Introduction part II.

Braz Oral Res 2020 9;34(supp1 1):e023. Epub 2020 Apr 9.

Latin American Oral Health Association - LAOHA, São Paulo, SP, Brazil.

The epidemiological data on gingivitis and periodontitis in Latin America are scarce, as the majority of the Latin American studies have analyzed probing depth instead of clinical attachment loss. Reported data have shown high variations in results between different Latin American countries, with the main causes of these differences being the clinical case definition and methodological strategies used. In general, data have revealed that the prevalence of periodontal disease is higher in Latin Americans than in populations in the USA or Europe. Regarding its relations with other diseases and conditions, some Latin American studies have focused on the association between periodontitis and adverse pregnancy outcomes, or poor glycemic control in diabetic patients; however, these studies have reported controversial results. In Chile, reports have indicated that periodontal treatment significantly reduced the preterm birth rate; however, no association between periodontitis and perinatal outcome was found in Brazil. For diabetes mellitus, Brazilian studies have reported controversial findings; however, a Chilean interventional study reported significant reductions in the glycosylated hemoglobin levels after periodontal treatment. Although epidemiological data for Latin America are scarce, the information available at present is useful for establishing national policies on health promotion, prevention, and treatment of periodontal disease. Therefore, dental schools must play a key role in educating professionals who are highly trained in the promotion, prevention, early diagnosis and treatment of periodontal disease, with an approach to risk, and strong biopsychosocial and ethical components. Thus, future Latin American dentists would be able to face the challenge of decreasing the prevalence of periodontal diseases by leading interdisciplinary health teamwork.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1590/1807-3107bor-2020.vol34.0023DOI Listing
May 2020

Interleukin-35 inhibits alveolar bone resorption by modulating the Th17/Treg imbalance during periodontitis.

J Clin Periodontol 2020 06 3;47(6):676-688. Epub 2020 Apr 3.

Periodontal Biology Laboratory, Faculty of Dentistry, Universidad de Chile, Santiago, Chile.

Aim: T lymphocytes play a central role during the pathogenesis of periodontitis, and the imbalance between the pathogenic T-helper type 17 (Th17) and protective T-regulatory (Treg) lymphocytes determines the tooth-supporting alveolar bone resorption. Interleukin (IL)-35 is a novel anti-inflammatory cytokine with therapeutic properties in diseases whose pathogenesis is associated with the Th17/Treg imbalance; however, its role during periodontitis has not been established yet. This study aimed to elucidate whether IL-35 inhibits the alveolar bone resorption during periodontitis by modulating the Th17/Treg imbalance.

Materials And Methods: Mice with ligature-induced periodontitis were treated with locally or systemically administrated IL-35. As controls, periodontitis-affected mice without IL-35 treatment and non-ligated mice were used. Alveolar bone resorption was measured by micro-computed tomography and scanning electron microscopy. The Th17/Treg pattern of the immune response was analysed by qPCR, ELISA, and flow cytometry.

Results: IL-35 inhibited alveolar bone resorption in periodontitis mice. Besides, IL-35 induced less detection of Th17 lymphocytes and production of Th17-related cytokines, together with higher detection of Treg lymphocytes and production of Treg-related cytokines in periodontitis-affected tissues.

Conclusion: IL-35 is beneficial in the regulation of periodontitis; particularly, IL-35 inhibited alveolar bone resorption and this inhibition was closely associated with modulation of the periodontal Th17/Treg imbalance.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/jcpe.13282DOI Listing
June 2020

Inflammatory markers IL-1β and RANK-L assessment after non-vital bleaching: A 3-month follow-up.

J Esthet Restor Dent 2020 Jan 26;32(1):119-126. Epub 2019 Dec 26.

Department of Restorative Dentistry, Faculty of Dentistry, University of Chile, Santiago, Chile.

Objective: This study assessed IL-1β and RANK-L levels in vivo and color stability of non-vital teeth bleached using hydrogen (35%) and carbamide (37%) peroxides 3 months after treatment.

Materials And Methods: Fifty teeth were randomly divided into two groups(n = 25):35% hydrogen peroxide (HP) or 37% carbamide peroxide (CP). Four sessions of intracoronal walking-bleach procedure were performed. IL-1β and RANK-L levels were assessed from gingival crevicular fluid samples (from three vestibular and three palatines sites) at eight different time-points: at the beginning of the study (baseline), after four sessions of intracanal bleaching, and at 1 week, 1 month, and 3 months posttreatment. The color variations were visually detected using Vita bleach shade guide (ΔSGU).

Results: Significant increases of IL-1β and RANK-L levels were detected at all time-points (all P < .05) when comparing each time-point to baseline, and a high correlation (>0.8-Spearman) between variables. According the ΔSGU values, a color change of five for HP and four for CP were detected.

Conclusions: Non-vital walking bleach technique promotes an increase in IL-1β and RANKL levels in periodontal tissues and also, it is maintained until the third-month posttreatment.

Clinical Significance: The internal whitening of teeth increases the levels of cytokines associated with inflammation and bone resorption 3 months after the whitening procedure is finished; this should warn of possible harmful effects of this whitening technique.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/jerd.12557DOI Listing
January 2020

Inhibitory effect of serotype a of Aggregatibacter actinomycetemcomitans on the increased destructive potential of serotype b.

Oral Dis 2020 Mar 12;26(2):409-418. Epub 2019 Dec 12.

Periodontal Biology Laboratory, Faculty of Dentistry, Universidad de Chile, Santiago, Chile.

Objective: The serotype b of Aggregatibacter actinomycetemcomitans (A. actinomycetemcomitans) induces higher cytokine production in dendritic cells (DCs) compared with the other serotypes. However, this increased immunostimulatory potential was modified when DCs were co-infected with the other A. actinomycetemcomitans serotypes. This study aimed to analyze whether the production of interferon gamma (IFN-γ), C-reactive protein (CRP), matrix metalloproteinase (MMP)-2, and MMP-9, as well as the activity of osteoclasts, also varies when DCs are co-infected with the A. actinomycetemcomitans serotypes.

Materials And Methods: Human DCs were stimulated with the A. actinomycetemcomitans serotypes using the following stimulatory conditions: serotype a/b/c/a+b/a+c/b+c/a+b+c. The IFN-γ, CRP, and MMP-2 levels were quantified by ELISA. The active form of MMP-9 was quantified using fluorescent functional assays. The MMP-2 gelatinolytic activity was identified by zymogram. The osteoclast activity was determined by quantifying the TRAP expression and resorption-pit formation using cytochemistry and osteoassays.

Results: Higher levels of IFN-γ, CRP, MMP-2, MMP-9, and osteoclast activity were detected when DCs were stimulated with the serotype b of A. actinomycetemcomitans compared with the others. This increased immunostimulatory potential attributed to serotype b diminished when DCs were co-infected with the serotype a.

Conclusions: This study provides new insights into the virulence of A. actinomycetemcomitans and reveals important differences in the immunostimulatory and pro-destructive potential among its serotypes.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/odi.13237DOI Listing
March 2020

Osteoimmunology of Oral and Maxillofacial Diseases: Translational Applications Based on Biological Mechanisms.

Front Immunol 2019 18;10:1664. Epub 2019 Jul 18.

Forsyth Institute, Cambridge, MA, United States.

The maxillofacial skeleton is highly dynamic and requires a constant equilibrium between the bone resorption and bone formation. The field of osteoimmunology explores the interactions between bone metabolism and the immune response, providing a context to study the complex cellular and molecular networks involved in oro-maxillofacial osteolytic diseases. In this review, we present a framework for understanding the potential mechanisms underlying the immuno-pathobiology in etiologically-diverse diseases that affect the oral and maxillofacial region and share bone destruction as their common clinical outcome. These otherwise different pathologies share similar inflammatory pathways mediated by central cellular players, such as macrophages, T and B cells, that promote the differentiation and activation of osteoclasts, ineffective or insufficient bone apposition by osteoblasts, and the continuous production of osteoclastogenic signals by immune and local stromal cells. We also present the potential translational applications of this knowledge based on the biological mechanisms involved in the inflammation-induced bone destruction. Such applications can be the development of immune-based therapies that promote bone healing/regeneration, the identification of host-derived inflammatory/collagenolytic biomarkers as diagnostics tools, the assessment of links between oral and systemic diseases; and the characterization of genetic polymorphisms in immune or bone-related genes that will help diagnosis of susceptible individuals.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3389/fimmu.2019.01664DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6657671PMC
October 2020

IL-22-expressing CD4 AhR T lymphocytes are associated with RANKL-mediated alveolar bone resorption during experimental periodontitis.

J Periodontal Res 2019 Oct 29;54(5):513-524. Epub 2019 Apr 29.

Faculty of Dentistry, Periodontal Biology Laboratory, Universidad de Chile, Santiago, Chile.

Background And Objective: Over the past few years, the importance of interleukin-22 (IL-22) and T-helper (Th)22 lymphocytes in the pathogenesis of periodontitis has become apparent; however, there are still aspects that are not addressed yet. Cells expressing IL-22 and aryl hydrocarbon receptor (AhR), transcription factor master switch gene implicated in the differentiation and function of Th22 lymphocytes, have been detected in periodontal tissues of periodontitis-affected patients. In addition, IL-22 has been associated with osteoclast differentiation and their bone resorptive activity in vitro. However, the destructive potential of IL-22-expressing AhR Th22 lymphocytes over periodontal tissues during periodontitis has not been demonstrated in vivo yet. Therefore, this study aimed to analyze whether IL-22-expressing CD4 AhR T lymphocytes detected in periodontal lesions are associated with alveolar bone resorption during experimental periodontitis.

Material And Methods: Using a murine model of periodontitis, the expression levels of IL-22 and AhR, as well as the Th1-, Th2-, Th17- and T regulatory-associated cytokines, were analyzed in periodontal lesions using qPCR. The detection of CD4 IL-22 AhR T lymphocytes was analyzed in periodontal lesions and cervical lymph nodes that drain these periodontal lesions using flow cytometry. In addition, the expression of the osteoclastogenic mediator called receptor activator of nuclear factor-κB ligand (RANKL) was analyzed by qPCR, western blot, and immunohistochemistry. Finally, alveolar bone resorption was analyzed using micro-computed tomography and scanning electron microscopy, and the bone resorption levels were correlated with IL-22 and RANKL expression.

Results: Higher levels of IL-22, AhR, and RANKL, as well as IL-1β, IL-6, IL-12, IL-17, IL-23, and TNF-α, were expressed in periodontal lesions of infected mice compared with periodontal tissues of sham-infected and non-infected controls. Similarly, high RANKL immunoreaction was observed in periodontal tissues of infected mice; however, few or absent RANKL immunoreaction was observed in controls. This association between RANKL and periodontal infection was ratified by western blot. Furthermore, a higher detection of CD4 IL-22 AhR T lymphocytes was found in periodontal lesions and cervical lymph nodes that drain these periodontal lesions in infected mice compared with non-infected controls. Finally, the increased IL-22 and RANKL expression showed positive correlation between them and with the augmented alveolar bone resorption observed in experimental periodontal lesions.

Conclusion: This study demonstrates the increase of IL-22-expressing CD4 AhR T lymphocytes in periodontitis-affected tissues and shows a positive correlation between IL-22, RANKL expression, and alveolar bone resorption.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/jre.12654DOI Listing
October 2019

Brucella canis induces canine CD4 T cells multi-cytokine Th1/Th17 production via dendritic cell activation.

Comp Immunol Microbiol Infect Dis 2019 Feb 30;62:68-75. Epub 2018 Nov 30.

Periodontal Biology Laboratory, Faculty of Dentistry, Universidad de Chile, Santiago, Chile; Dentistry Unit, Faculty of Health Sciences, Universidad Autónoma de Chile, Santiago, Chile. Electronic address:

Brucella canis is a small intracellular Gram-negative bacterium that frequently leads to chronic infections highly resistant to antibiotic therapy in dogs. Also, it causes mild human brucellosis compared to other zoonotic Brucella spp. Herein we characterize the cellular immune response elicited by B. canis by analysing human and canine CD4 T cells after stimulation with autologous monocyte-derived dendritic cells (MoDCs). Human and canine B. canis-primed MoDCs stimulated autologous CD4 T cells; however, a Th1 response was triggered by human MoDCs, whereas canine MoDCs induced Th1/Th17 responses, with increased CD4 T cells producing IFN-γ and IL-17A simultaneously. Each pattern of cellular response may contribute to host susceptibility, helping to understand the differences in B. canis virulence between these two hosts. In addition, other aspects of canine immunology are unveiled by highlighting the participation of IL-17A-producing canine MoDCs and CD4 T cells producing IFN-γ and IL-17A.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.cimid.2018.11.017DOI Listing
February 2019

Multifunctional nanocarriers for the treatment of periodontitis: Immunomodulatory, antimicrobial, and regenerative strategies.

Oral Dis 2019 Nov 10;25(8):1866-1878. Epub 2019 Jan 10.

Periodontal Biology Laboratory, Department of Conservative Dentistry, Faculty of Dentistry, Universidad de Chile, Santiago, Chile.

Periodontitis is an inflammatory disease, in which the host immuno-inflammatory response against the dysbiotic subgingival biofilm leads to the breakdown of periodontal tissues. Most of the available treatments seem to be effective in the short-term; nevertheless, permanent periodical controls and patient compliance compromise long-term success. Different strategies have been proposed for the modulation of the host immune response as potential therapeutic tools to take a better care of most susceptible periodontitis patients, such as drug local delivery approaches. Though, maintaining an effective drug concentration for a prolonged period of time has not been achieved yet. In this context, advanced drug delivery strategies using biodegradable nanocarriers have been proposed to avoid toxicity and frequency-related problems of treatment. The versatility of distinct nanocarriers allows the improvement of their loading and release capabilities and could be potentially used for microbiological control, periodontal regeneration, and/or immunomodulation. In the present review, we revise and discuss the most frequent biodegradable nanocarrier strategies proposed for the treatment of periodontitis, including polylactic-co-glycolic acid (PLGA), chitosan, and silica-derived nanoparticles, and further suggest novel therapeutic strategies.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/odi.13023DOI Listing
November 2019

The therapeutic potential of regulatory T lymphocytes in periodontitis: A systematic review.

J Periodontal Res 2019 Jun 25;54(3):207-217. Epub 2018 Nov 25.

Department of Periodontology and Operative Dentistry, Faculty of Dentistry, University of Münster, Münster, Germany.

This systematic review aimed to: (a) generate a descriptive synthesis of preclinical studies assessing the therapeutic potential of regulatory T lymphocytes (Tregs) to arrest periodontitis, (b) evaluate the methodological heterogeneity of the reviewed animal studies and (c) assess the risk of bias (RoB) of the included studies. The electronic search for animal studies included the MEDLINE, EMBASE, Web of Science and LILACS databases. In addition, a manual search assessed the high-ranked scientific journals in "periodontics/immunology" and the references listed in the included studies. There were no language, year or publication status restrictions. Two independent reviewers selected and extracted the data, and Cohen's Kappa coefficient was calculated to determine the inter-examiner agreement. The Systematic Review Center for Laboratory Animal Experimentation's (SYRCLE) tool was used to assess the RoB. A total of 21 of the 425 studies obtained from the database search were included. Treg function was mainly described in Porphyromonas gingivalis-induced periodontitis (57.1%) in mice (76.2%), where Treg suppression was strongly related to disease progression and Treg induction was strongly related to immuno-inflammatory response reduction. Of those 21 studies, eight included eight animal experiments using three distinct therapeutic approaches, including: P. gingivalis-driven immunization (n = 3), retinoic acid inoculation (n = 2) and anti-inflammatory molecules in polymeric carriers (n = 3), which could modulate the Treg activity through cytokine production (interleukin-10 and transforming growth factor-β1), CC-chemokine- and CC-chemokine receptor-mediated chemoattraction (CCL22 and CCR4) or Th17-associated receptor activator of nuclear factor κB ligand (RANKL) downregulation. However, the studies with animal experiments did not specify the randomization sequences and housing conditions that were used, and therefore, 42.11% of the entries were rated as unclear RoB. Distinct therapeutic strategies involving Tregs could potentially suppress the immuno-inflammatory response and restore alveolar bone homeostasis during periodontitis. Nevertheless, important methodological variability, poor reporting of treatment effect estimates and unclear RoB suggest using caution when assessing the results of these studies.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/jre.12629DOI Listing
June 2019

Capsular-defective Porphyromonas gingivalis mutant strains induce less alveolar bone resorption than W50 wild-type strain due to a decreased Th1/Th17 immune response and less osteoclast activity.

J Periodontol 2019 05 20;90(5):522-534. Epub 2018 Dec 20.

Periodontal Biology Laboratory, Faculty of Dentistry, Universidad de Chile, Chile.

Background: Encapsulation of Porphyromonas gingivalis has been demonstrated as responsible of several host immunological changes, which have been associated with the pathogenesis of periodontitis. Using a murine model of periodontitis and two isogenic non-capsulated mutants of P. gingivalis, this study aimed to analyze whether P. gingivalis encapsulation induces more severe alveolar bone resorption, and whether this bone loss is associated with a T-helper (Th)1 and Th17-pattern of immune response.

Methods: Experimental periodontal infections were generated by oral inoculation with the encapsulated W50 wild-type strain or isogenic non-encapsulated ΔPG0116-PG0120 (GPA) and ΔPG0109-PG0118 (GPC) mutants of P. gingivalis. Periodontal infections induced with the encapsulated HG184 or non-encapsulated ATCC 33277 strains of P. gingivalis were used as controls. Alveolar bone resorption was analyzed using microcomputed tomography and scanning electron microscopy. The expression levels of Th1, Th2, Th17, or T regulatory-associated cytokines and RANKL, as well as the periodontal bacterial load, were quantified by quantitative polymerase chain reaction. The detection of Th1 and Th17 lymphocytes was analyzed by flow cytometry.

Results: In the periodontal lesions, both capsular-defective knockout mutant strains of P. gingivalis induced less alveolar bone resorption than the encapsulated W50 wild-type strain. This decreased bone loss was associated with a dismissed RANKL expression, decreased Th1- and Th17-type of cytokine expression, reduced Th1 and Th17 lymphocyte detection, and low osteoclast finding.

Conclusion: These data demonstrate that encapsulation of P. gingivalis plays a key role in the alveolar bone resorption induced during periodontitis, and this bone loss is associated with a Th1- and Th17-pattern of immune response triggered in the periodontal lesions.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/JPER.18-0079DOI Listing
May 2019

Immunostimulatory activity of low-molecular-weight hyaluronan on dendritic cells stimulated with Aggregatibacter actinomycetemcomitans or Porphyromonas gingivalis.

Clin Oral Investig 2019 Apr 17;23(4):1887-1894. Epub 2018 Sep 17.

Periodontal Biology Laboratory, Faculty of Dentistry, Universidad de Chile, Sergio Livingstone Pohlhammer 943, 8380492, Independencia, Santiago, Chile.

Objectives: Periodontitis is a chronic inflammatory disease characterized by tooth-supporting tissue destruction, which is elicited by the host's immune response triggered against periodonto-pathogen bacteria. During periodontal tissue destruction, extracellular matrix components are metabolized and fragmented. Some extracellular matrix component-derived fragments, such as low-molecular-weight hyaluronan (LMW-HA), have potent immunogenic potential, playing a role as damage-associated molecular patterns (DAMPs) during activation of immune cells. Dendritic cells (DCs) play a central role in the host's immune response displayed during periodontitis; thus, this study aimed to analyze whether LMW-HA has an immunostimulatory activity on DCs when stimulated with periodonto-pathogen bacteria.

Materials And Methods: LMW-HA-treated and non-treated DCs were stimulated with Aggregatibacter actinomycetemcomitans or Porphyromonas gingivalis and the mRNA expression for cytokines tumor necrosis factor-α (TNF-alpha), interleukin-1β (IL-1B), interleukin-6 (IL-6), and interleukin-23 (IL-23A) was quantified by RT-qPCR. In addition, transcription factors interferon regulatory factor 4 (IRF4), interferon regulatory factor 8 (IRF8), neurogenic locus notch homolog protein 2 (NOTCH2), and basic leucine zipper ATF-like transcription factor 3 (BATF3), involved in DC activation, were analyzed.

Results: Higher expression levels of TNF-alpha, IL-1B, IL-6, and IL-23A were detected in LMW-HA-treated DCs after bacterial infection, as compared with non-treated DCs. When LMW-HA-treated DCs were infected with A. actinomycetemcomitans, higher levels of IRF4, NOTCH2, and BATF3 were detected compared with non-treated cells; whereas against P. gingivalis infection, increased levels of IRF4 and NOTCH2 were detected.

Conclusion: LMW-HA plays an immunostimulatory role on the immune response triggered by DCs during infection with A. actinomycetemcomitans or P. gingivalis.

Clinical Relevance: Detection of extracellular matrix component-derived fragments produced during periodontal tissue destruction, such as LMW-HA, could explain at least partly unsuccessful periodontal treatment and the chronicity of the disease.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s00784-018-2641-5DOI Listing
April 2019

Quality of life and stability of tooth color change at three months after dental bleaching.

Qual Life Res 2018 Dec 21;27(12):3199-3207. Epub 2018 Aug 21.

Department of Restorative Dentistry, Faculty of Dentistry, University of Chile, Independencia, Santiago, Chile.

Purpose: Intracoronary bleaching is a minimally invasive, alternative treatment that addresses aesthetic concerns related to non-vital teeth discoloration. However, to the best of our knowledge, no studies have assessed the psychosocial impacts of such procedures on patients' aesthetic perceptions. The aim of this study was to evaluate aesthetic perceptions and the psychosocial impact of patients up to 3 months after their teeth had been bleached with hydrogen peroxide (35%) and carbamide peroxide (37%) using the walking bleach technique.

Methods: The patients were randomly divided into two groups according to the bleaching agent used: G1 = hydrogen peroxide 35% (n = 25) and G2 = carbamide peroxide 37% (n = 25). Non-vital bleaching was performed in four sessions. Color was objectively (ΔE) and subjectively (ΔSGU) evaluated. Aesthetic perception and psychosocial factors were evaluated before, 1 week and 1 month after the bleaching using the Oral Health Impact Profile (OHIP) and Psychosocial Impact of Dental Aesthetics Questionnaire (PIDAQ) questionnaires.

Results: The color change (ΔE) values at 1 month were G1 = 16.80 ± 6.07 and G2 = 14.09 ± 4.83. These values remained stable until the third month after treatment (p > 0.05). There was a decrease in the values of OHIP-aesthetics and PIDAQ after treatment versus baseline (p < 0.05). This status was maintained through the third month after treatment.

Conclusions: Both agents were highly effective and had a positive impact on the aesthetic perception and psychosocial impact of patients, values that also remained stable over time. Non-vital bleaching yields positive and stable impacts on aesthetic perception and psychosocial factors. ClinicalTrials.gov identifier NCT02718183.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s11136-018-1972-7DOI Listing
December 2018

Alveolar bone resorption and Th1/Th17-associated immune response triggered during Aggregatibacter actinomycetemcomitans-induced experimental periodontitis are serotype-dependent.

J Periodontol 2018 10 20;89(10):1249-1261. Epub 2018 Aug 20.

Periodontal Biology Laboratory, Faculty of Dentistry, Universidad de Chile, Santiago, Chile.

Background: Aggregatibacter actinomycetemcomitans expresses several virulence factors that may contribute to the pathogenesis of periodontitis. Based on the antigenicity of the O-polysaccharide component of the lipopolysaccharide (LPS), different A. actinomycetemcomitans serotypes have been described. Among them, serotype b has demonstrated a stronger capacity to trigger Th1 and Th17-associated cytokine, CC-chemokine, and CC-chemokine receptor production on immune cells in vitro. With a murine model of experimental periodontitis, this investigation aimed to analyze the alveolar bone resorption and the pattern of immune response triggered by the different A. actinomycetemcomitans serotypes within periodontal lesions.

Methods: For periodontal lesion induction, mice were orally infected with the different A. actinomycetemcomitans serotypes or their purified LPS. Alveolar bone resorption was analyzed using microcomputed tomography and scanning electron microscopy. Bacterial infection, receptor activator of nuclear factor-kappa B ligand (RANKL) and Th1 and Th17-associated cytokine, CC-chemokine, and CC-chemokine receptor levels were quantified by quantitative polymerase chain reaction (qPCR). T lymphocytes isolated from periodontal lesions were analyzed by flow cytometry.

Results: In periodontal lesions, serotype b of A. actinomycetemcomitans induced higher alveolar bone resorption and expression of RANKL compared with the other serotypes. In addition, serotype b induced greater levels of Th1- and Th17-related cytokines, CC-chemokines, and CC-chemokine receptors than the others. Similarly, higher numbers of infiltrating Th1 and Th17 lymphocytes were detected in serotype b-induced periodontal lesions.

Conclusions: These results demonstrate that periodontal lesions induced with different A. actinomycetemcomitans serotypes elicited distinct alveolar bone resorption and immune response. In particular, serotype b was more pathogenic than the others and induced stronger Th1 and Th17 patterns of immune responses during experimental periodontitis.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/JPER.17-0563DOI Listing
October 2018

Serotype a of Aggregatibacter actinomycetemcomitans down-regulates the increased serotype b-induced cytokine and chemokine production in dendritic cells.

Arch Oral Biol 2018 09 12;93:155-162. Epub 2018 Jun 12.

Periodontal Biology Laboratory, Faculty of Dentistry, Universidad de Chile, Santiago, Chile; Dentistry Unit, Faculty of Health Sciences, Universidad Autónoma de Chile, Santiago, Chile. Electronic address:

Objective: In Aggregatibacter actinomycetemcomitans, different serotypes have been described based on LPS antigenicity. Mixed infection with the different A. actinomycetemcomitans serotypes is frequent in periodontitis patients; accordingly, the role of this bacterial species in the pathogenesis of periodontitis may differ depending whether patients or periodontal lesions harbour one or more of the A. actinomycetemcomitans serotypes. We hypothesized that different combinations of these serotypes could be associated with distinct host responses and hence different inflammatory patterns. This investigation was aimed to assess whether the increased immuno-stimulatory potential attributed to the serotype b of A. actinomycetemcomitans on immune cells is able to be modified during co-infection with other A. actinomycetemcomitans serotypes.

Methods: Dendritic cells (DCs) were obtained from healthy subjects and stimulated with the different A. actinomycetemcomitans serotypes or their purified LPS using the following stimulatory conditions: serotype a, b, or c, and the combinations a+b, a+c, b+c, or a+b+c. The cytokine, CCR, and CCL levels were quantified by qPCR and ELISA.

Results: Higher levels of cytokines, CCRs, and CCLs were induced when DCs were stimulated with the serotype b of A. actinomycetemcomitans compared with the same cells stimulated with the other serotypes. When DCs were co-infected, these levels decreased in comparison with the serotype b-stimulation alone, in particular when the serotype a was present in the mixed infection.

Conclusions: The increased immuno-stimulatory potential attributed to the serotype b was modified when DCs were co-infected with other A. actinomycetemcomitans serotypes, in particular, when the serotype a was present, the DC response diminished.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.archoralbio.2018.06.010DOI Listing
September 2018

Regulatory T Lymphocytes in Periodontitis: A Translational View.

Mediators Inflamm 2018 2;2018:7806912. Epub 2018 Apr 2.

Periodontal Biology Laboratory, Faculty of Dentistry, Universidad de Chile, Santiago, Chile.

Periodontitis is a chronic immuno-inflammatory disease in which the disruption of the balance between host and microbiota interactions is key to the onset and progression of the disease. The immune homeostasis associated with periodontal health requires a regulated immuno-inflammatory response, during which the presence of regulatory T cells (Tregs) is essential to ensure a controlled response that minimizes collateral tissue damage. Since Tregs modulate both innate and adaptive immunity, pathological conditions that may resolve by the acquisition of immuno-tolerance, such as periodontitis, may benefit by the use of Treg immunotherapy. In recent years, many strategies have been proposed to take advantage of the immuno-suppressive capabilities of Tregs as immunotherapy, including the and manipulation of the Treg compartment. Ongoing research in both basic and translational studies let us gain a better understanding of the diversity of Treg subsets, their phenotypic plasticity, and suppressive functions, which can be used as a substrate for new immunotherapies. Certainly, as our knowledge of Treg biology increases, we will be capable to develop new therapies designed to enhance the stability and function of Tregs during periodontitis.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1155/2018/7806912DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5901475PMC
October 2018
-->