Phagocytosis and nitric oxide production by peritoneal adherent cells in response to Candida albicans in aging: a collaboration to elucidate the pathogenesis of denture stomatitis

Elderly denture wearers are commonly affected by Candida-associated denture stomatitis (DS), an inflammatory process of the oral mucosa strongly associated with Candida spp and other microorganisms, as well as local and systemic factors. The impaired immune response against pathogens is among the inherent host factors that have been also associated with the pathogenesis of DS. Mononuclear phagocytes respond to the pathogens through phagocytosis followed by the production of several substances inside the phagosomes, among them are the reactive nitrogen species (RNS). A failure in these mechanisms may contribute to the DS development. Objective The aim of this study was to investigate the influence of aging on the internalization and the production of nitric oxide (NO) by peritoneal adherent cells (PAC), in response to Candida albicans (C. albicans). Material and methods PAC obtained from young and aged mice were challenged with dead or viable C. albicans by using predetermined proportions (cells:yeast) for 30 and 120 minutes. Phagocytosis was analyzed by acridine orange dye, and NO production by the Griess reaction. Results C. albicans phagocytosis by PAC from aged mice was similar to that of young mice, although the cells from older mice cells present more internalized fungi compared with matched control. In addition, a tendency towards impaired NO production by peritoneal mononuclear phagocytes from aged mice was observed. Conclusions PAC from aged mice may capture and store many fungi, which in turn may mean that these cells are effectively unable to eliminate fungi, probably due to impaired NO production. Therefore, considering the important role of C. albicans overgrowth in the pathogenesis of DS and the aspects observed in this study, aging may favor the onset and severity of local candidosis such as DS and its systemic forms

The Importance of a Proper Selection Area to be Biopsied in Nodular Leukoplakia: a Case Report

Nodularna leukoplakija je nehomogeni oblik oralne leukoplakije obično s bijelom bradavičastom, nodularnom, ulceriranom ili eritematoznom (crvenkastom) površinom s velikim rizikom od pretvorbe u malignu tvorbu u usporedbi s homogenim oblikom. Najčešće zahvaća komisure usnica, obraznu sluznicu i meko nepce. Često je povezana s epitelnom displazijom ili karcinomom, pa je prijeko potrebna detaljna mikroskopska procjena, a poslije redovite kontrole. Temelj za postavljanje točne dijagnoze jest odabrati pravo mjesto za biopsiju, ali i bliska suradnja liječnika dentalne medicine i oralnog patologa.Nodular leukoplakia is a non-homogeneous type of oral leukoplakia presenting a white surface with verrucous, nodular, ulcerated or erythematous features with a greater risk of malignant transformation when compared to the homogeneous type. Common sites of involvement include lip commissures, buccal mucosa and soft palate. It is often associated with epithelial dysplasia or carcinoma and requires detailed microscopic assessment and regular follow-up. The importance of a proper selection of the area to be biopsied and the close teamwork between a dentist and oral pathologist is the basis of providing an accurate final diagnosis

Evaluation of the phagocytic ability of mast cells against the periodontopathogens Aggregatibacter actinomycetemcomitans

As doenças periodontais afetam os tecidos de suporte dos dentes e são desencadeadas por microrganismos que possuem a capacidade de invadir os tecidos periodontais. A evolução desta doença é influenciada pela resposta inflamatória e imunológica do hospedeiro e envolve a participação de diversos tipos celulares. Atualmente, existem evidências de que os mastócitos, além de outras funções, possuem a capacidade de eliminar bactérias, através da fagocitose. Assim sendo, este estudo teve por objetivo avaliar a capacidade fagocítica dos mastócitos frente ao periodontopatógeno A. actinomycetemcomitans, além de comparar sua capacidade fagocítica com a dos macrófagos, considerados fagócitos profissionais. Para este fim, foram realizados ensaios fagocíticos in vitro utilizando mastócitos e macrófagos murinos, desafiados ora com A. actinomycetemcomitans ora com Escherichia coli, opsonizados ou não, sob diferentes proporções célula: bactérias. Após 1 hora de desafio, as células foram coradas com laranja de acridina e avaliadas qualitativamente utilizando-se microscópio de varredura confocal a laser e quantitativamente através do microscópio de fluorescência convencional. Nossos resultados demonstraram que os mastócitos murinos se mostraram eficientes quanto a sua capacidade fagocítica frente a A. actinomycetemcomitans. Os valores percentuais de mastócitos com A. actinomycetemcomitans internalizados, na ausência de opsonização com complemento, foram maiores que aqueles na presença da opsonização, sugerindo a participação de receptores opsoninas-independentes no reconhecimento deste patógeno pelos mastócitos, além do receptor de complemento tipo 3 (CR3). Comparando os dois tipos celulares, verificou-se que ambas as células apresentaram importante atividade fagocítica contra A. actinomycetemcomitans, porém os valores percentuais de mastócitos com bactérias internalizadas sem complemento foram maiores que aqueles de macrófagos com bactérias internalizadas com complemento, em uma das proporções (1:10). Os resultados deste trabalho sugerem o papel dos mastócitos como fagócitos profissionais na patogênese da doença periodontal induzida por placa dentobacteriana.Periodontal diseases affect the supporting tissues of the teeth and are triggered by microorganisms which are capable of invading periodontal tissues. The evolution of this disease is influenced by inflammatory and immune response of the host and involves the participation of different cell types. Currently, there is evidence that mast cells, among other functions, have the ability to eliminate bacteria by phagocytosis. Thus, this study aimed to evaluate the phagocytic ability of mast cells against the periodontopathogens A. actinomycetemcomitans, and compare with the phagocytic capacity of macrophages, which are considered professional phagocytes. Therefore, in vitro phagocytic assays were conducted using murine mast cells and macrophages, challenged with A. actinomycetemcomitans or Escherichia coli, at the same time, opsonized or not, under different proportions cell: bacteria. After 1 hour of challenge, cells were stained with acridine orange and qualitatively assessed by using a confocal laser scanning electron microscope and quantitatively by the conventional scanning fluorescence microscope. The results demonstrated that phagocytic ability of murine mast cells was effective against A. actinomycetemcomitans. The percentages of mast cells with A. actinomycetemcomitans internalized in the absence of opsonization with complement, were higher than those in the presence of opsonization, suggesting the involvement of opsonin-independent receptors in recognition of this pathogen by mast cells, as well as complement receptor type 3 (CR3). Comparing the two cell types, it was observed that both cells showed significant phagocytic activity against A. actinomycetemcomitans, however, the percentages of mast cells with internalized bacteria without complement were higher than those of macrophages with internalized bacteria with complement, in one of the proportions (1:10). The results suggest the role of mast cells as professional phagocytes in the pathogenesis of periodontal disease induced by dental plaque

Defense mechanisms of mast cells against periodontopathogen Aggregatibacter actinomycetemcomitans: intracellular microbicidal activity

Os mastócitos (MCs) estão presentes tanto no periodonto normal quanto inflamado, em diferentes quantidades e em vários locais. Nos últimos anos, a eficácia e a contribuição dos MCs em eliminar bactérias, através de sua atividade microbicida intracelular, estão se tornando cada vez mais reconhecidas. Assim, a partir de MCs murinos desafiados in vitro com o periodontopatógeno Aggregatibacter actinomycetemcomitans (ATCC 29523) por 3, 5, 10 e 24 horas, o presente estudo teve como objetivo investigar a capacidade microbicida intracelular de MCs, e comparar com a capacidade microbicida de macrófagos peritoneais murinos (MPs), considerados fagócitos profissionais, por meio da contagem das unidades formadoras de colônias. Além disso, avaliou-se a produção e liberação de mediadores microbicidas, óxido nítrico (NO) e peróxido de hidrogênio (H2O2), por meio do método colorimétrico de Griess e pela degradação de substratos fluorescentes, respectivamente. Para a análise estatística, foram utilizados os testes estatísticos ANOVA Fatorial seguido do teste de Tukey e teste de correlação de Pearson (p<0.05). Nossos resultados revelaram que os MCs foram capazes de eliminar eficientemente o periodontopatógeno, principalmente após 10h de desafio intracelular. Comparando-se a atividade microbicida dos dois tipos celulares, verificou-se, nos períodos de 3h e 5h de desafio, um menor percentual de colônias viáveis no interior de MPs, em comparação aos MCs. Inversamente, nos períodos de 10h e 24h, observaram-se menores valores percentuais de colônias intracelulares nos MCs em relação aos MPs. Além disso, a produção/liberação de NO bem como, em menor proporção, de H2O2 pelos MCs foram concordantes com a sua capacidade microbicida. Este é o primeiro estudo que demonstra a eficiente ação microbicida intracelular de MCs murinos contra Aggregatibacter actinomycetemcomitans, com produção e liberação de substâncias potencialmente bactericidas, e de forma mais eficaz que os macrófagos. Esses resultados sugerem a importância dessas células nos mecanismos de defesa presentes na doença periodontal induzida por placa dentobacteriana.Mast cells (MCs) are present in both normal and inflamed periodontal tissues, in varying amounts and locations. Recently, MCs contribution in eliminating bacteria and its effectiveness, through its intracellular microbicidal activity, have been increasingly recognized. Thus, this study aimed to investigate the intracellular microbicide capacity of MCs, and compare it with the microbicide capacity of murine peritoneal macrophages (MPs), considered professional phagocytes, by counting the colony forming units. Both cell types were challenged in vitro with periodontopathogen Aggregatibacter actinomycetemcomitans (ATCC 29523) by 3, 5, 10 and 24 hours. Additionally, the production and release of microbicidal agents, nitric oxide (NO) and hydrogen peroxide (H2O2) were evaluated by means of colorimetric Griess method and by the degradation of fluorescent substrates, respectively. Statistical analysis was performed by ANOVA Factorial test followed by Tukey and Pearson\'s correlation test (p <0.05). Our results revealed that MCs are able to efficiently eliminate periodontopathogen, mainly after 10 hours of intracellular challenge. The microbicidal activity of both cell types, in 3 and 5 hours of challenge showed a lower percentage of viable colonies inside MPs, compared to MCs. Contradictorily, in 10 and 24 hours a lower percentage of intracellular colonies in MCs was observed in relation to MPs. Moreover, the production/release of NO and, in minor proportion, of H2O2 by MCs was in agreement with its microbicidal capacity. Therefore, this is the first report to describe the intracellular microicidal activity of murine MCs against Aggregatibacter actinomycetemcomitans, concerning production and release of potentially bactericidal substances, which is more effective than macrophages. These results suggest the importance of these cells in pathogenesis and defense mechanisms of biofilm-associated periodontal disease

Phagocytosis and nitric oxide production by peritoneal adherent cells in response to Candida albicans in aging: a collaboration to elucidate the pathogenesis of denture stomatitis

Abstract Elderly denture wearers are commonly affected by Candida-associated denture stomatitis (DS), an inflammatory process of the oral mucosa strongly associated with Candida spp and other microorganisms, as well as local and systemic factors. The impaired immune response against pathogens is among the inherent host factors that have been also associated with the pathogenesis of DS. Mononuclear phagocytes respond to the pathogens through phagocytosis followed by the production of several substances inside the phagosomes, among them are the reactive nitrogen species (RNS). A failure in these mechanisms may contribute to the DS development. Objective The aim of this study was to investigate the influence of aging on the internalization and the production of nitric oxide (NO) by peritoneal adherent cells (PAC), in response to Candida albicans (C. albicans). Material and methods PAC obtained from young and aged mice were challenged with dead or viable C. albicans by using predetermined proportions (cells:yeast) for 30 and 120 minutes. Phagocytosis was analyzed by acridine orange dye, and NO production by the Griess reaction. Results C. albicans phagocytosis by PAC from aged mice was similar to that of young mice, although the cells from older mice cells present more internalized fungi compared with matched control. In addition, a tendency towards impaired NO production by peritoneal mononuclear phagocytes from aged mice was observed. Conclusions PAC from aged mice may capture and store many fungi, which in turn may mean that these cells are effectively unable to eliminate fungi, probably due to impaired NO production. Therefore, considering the important role of C. albicans overgrowth in the pathogenesis of DS and the aspects observed in this study, aging may favor the onset and severity of local candidosis such as DS and its systemic forms

PROCESSOS PROLIFERATIVOS NÃO NEOPLÁSICOS

Este recurso educacional aberto (REA) foi confeccionado com o objetivo de facilitar o entendimento a respeito dos Processos Proliferativos Não Neoplásicos (PPNN), e despertar o interesse dos graduandos do curso de Odontologia a respeito do assunto. Durante a leitura do REA o acadêmico encontrará dicas, curiosidades, imagens clínicas e histopatológicas, conteúdo teórico e estudo dirigido sobre os PPNN da cavidade oral. Os PPNN são um grupo de lesões comuns na boca, que possuem um crescimento tecidual exofítico de natureza inflamatória, e que não apresentam características histológicas neoplásicas. As lesões em algumas semanas devido a sua natureza inflamatória podem ter um crescimento rápido e atingir grandes dimensões, motivo que leva o paciente a procurar o cirurgião-dentista. A própria denominação “processos proliferativos”, significa que as lesões possuem constituintes do tecido epitelial e/ou conjuntivo que irão proliferar e em resposta a um trauma contínuo e de baixa intensidade como o uso de próteses mal adaptadas, vício de morder a mucosa ou ainda em reposta a agentes irritantes locais, como o biofilme dental. Além dos aspectos clínicos, as características histopatológicas são essenciais para estabelecer o diagnóstico diferencial entre esse grupo de lesões. Serão abordados neste REA as lesões mais frequentes na rotina clínica, incluindo as hiperplasias fibrosas, dentre elas a hiperplasia fibrosa focal, hiperplasia fibrosa inflamatória, hiperplasia papilar inflamatória, hiperplasia por câmara de sucção, hiperplasia do freio, pólipo fibroepitelial, granuloma piogênico, o granuloma periférico de células gigantes e o fibroma ossificante periférico. São lesões prevalentes, e que são apresentadas clinicamente por pápulas ou nódulos, e tratados na maioria dos casos com excisão cirúrgica. O conhecimento dos aspectos clínicos e histopatológicos dos PPNN é fundamental para que os futuros cirurgiões dentistas realizem o diagnóstico diferencial com segurança

Guidance on mucositis assessment from the MASCC Mucositis Study Group and ISOO: an international Delphi studyResearch in context

Summary: Background: Mucositis is a common and highly impactful side effect of conventional and emerging cancer therapy and thus the subject of intense investigation. Although common practice, mucositis assessment is heterogeneously adopted and poorly guided, impacting evidence synthesis and translation. The Multinational Association of Supportive Care in Cancer (MASCC) Mucositis Study Group (MSG) therefore aimed to establish expert recommendations for how existing mucositis assessment tools should be used, in clinical care and trials contexts, to improve the consistency of mucositis assessment. Methods: This study was conducted over two stages (January 2022–July 2023). The first phase involved a survey to MASCC-MSG members (January 2022–May 2022), capturing current practices, challenges and preferences. These then informed the second phase, in which a set of initial recommendations were prepared and refined using the Delphi method (February 2023–May 2023). Consensus was defined as agreement on a parameter by >80% of respondents. Findings: Seventy-two MASCC-MSG members completed the first phase of the study (37 females, 34 males, mainly oral care specialists). High variability was noted in the use of mucositis assessment tools, with a high reliance on clinician assessment compared to patient reported outcome measures (PROMs, 47% vs 3%, 37% used a combination). The World Health Organization (WHO) and Common Terminology Criteria for Adverse Events (CTCAE) scales were most commonly used to assess mucositis across multiple settings. Initial recommendations were reviewed by experienced MSG members and following two rounds of Delphi survey consensus was achieved in 91 of 100 recommendations. For example, in patients receiving chemotherapy, the recommended tool for clinician assessment in clinical practice is WHO for oral mucositis (89.5% consensus), and WHO or CTCAE for gastrointestinal mucositis (85.7% consensus). The recommended PROM in clinical trials is OMD/WQ for oral mucositis (93.3% consensus), and PRO-CTCAE for gastrointestinal mucositis (83.3% consensus). Interpretation: These new recommendations provide much needed guidance on mucositis assessment and may be applied in both clinical practice and research to streamline comparison and synthesis of global data sets, thus accelerating translation of new knowledge into clinical practice. Funding: No funding was received