Candida lipases: a review on biochemical, molecular and pathogenic aspects. / [Lipasas de especies Candida: una revisión sobre aspectos bioquímicos, moleculares y patogénicos.]

In the last half century there was a significant increase in the incidence of fungal infections being likely to become a global health priority. The sophisticated degree of host-Candida interaction is the product of different virulence strategies used by the fungus to invade the tissues and the various defense mechanisms that it develops to control it. There is a significant amount of literature that indicates that this opportunistic commensal fungus has components that can be considered virulence factors related to the stage of the infectious process. Among the virulence factors of this fungus can be mentioned the adherence to cell surfaces, the formation of biofilms and the production of hydrolytic enzymes. The most studied hydrolases secreted by C. albicans are aspartyl proteinases, phospholipases and esterases, while lipases have been the least studied. These enzymes would have the function to facilitate active penetration into the cells, participating in the digestion and synthesis of lipid esters for their nutrition and contributing to the invasion of the tissue by hydrolyzing the lipid components of the host cell membranes. There is also bibliographic evidence that these enzymes are capable to damage cells and molecules of the immune system to avoid the antimicrobial activity.Taking into account the foregoing, this review provides an updated description of biochemical and molecular characteristics of the lipases secreted by Candida, its role as a virulence factor and its potential for the development of new antifungal drugs.

En el último medio siglo se produjo un aumento significativo en la incidencia de infecciones fúngicas siendo probable que se conviertan en una prioridad de salud global. El sofisticado grado de interacción hospedador-Candida es producto de diferentes estrategias de virulencia que utiliza el hongo para invadir los tejidos y de los diversos mecanismos de defensa que este último desarrolla para controlarlo. Existe bibliografía que indica que este hongo comensal oportunista posee componentes que pueden ser considerados factores de virulencia asociados a la etapa del proceso infeccioso. Dentro de los factores de virulencia de este hongo pueden mencionarse la adherencia a las superficies celulares, la formación de biofilms y la producción de enzimas hidrolíticas. Las hidrolasas secretadas por C. albicans más estudiadas son las aspartil proteinasas, las fosfolipasas y las esterasas, mientras que las lipasas han sido las menos exploradas. Estas enzimas tendrían como función facilitar la penetración activa en las células, participar en la digestión y síntesis de ésteres de lípidos para su nutrición y contribuir a la invasión del tejido al hidrolizar los componentes lipídicos de las membranas celulares del hospedador. También hay evidencia bibliográfica que indica que estas enzimas son capaces de dañar células y moléculas del sistema inmune para evitar la actividad antimicrobiana. Teniendo en cuenta lo precedente, esta revisión, proporciona una actualizada descripción de las características bioquímicas y moleculares de las lipasas secretadas por el hongo Candida, su rol como factor de virulencia y su potencial para el desarrollo de nuevos fármacos antifúngicos.

Study of virulence factor of Candida species in oral lesions and its association with potentially malignant and malignant lesions.

OBJECTIVE: The aim of this study was to explore the association between malignant and premalignant lesions and the virulence factor profile of Candida spp. recovered from different oral lesions. DESIGN: Candida spp. isolated from malignant lesions (squamous cell carcinoma, OC, n = 25), atypical lichen planus (AL, n = 11), chronic candidiasis (CC, n = 25), and asymptomatic carriers (WI, n = 15, control strains.) Isolates were identified in chromogenic medium, colony morphology and biochemical tests. The lipolytic and proteinase activity was determined on supplemented agar with olive oil and BSA, respectively. The biofilm formation with XTT reduction assay and cellular surface hydrophobicity (CSH) by water-hydrocarbon method were performed. RESULTS: All isolates recovered from oral lesions produced the four virulence factors studied with significantly higher levels than in WI isolates. Interestingly, lipolytic activity was absent in WI isolates. The proteolytic activity was similar in AL and OC isolates. OC isolates showed significantly higher CSH values than other clinical isolates. Non-albicans species showed higher biofilm formation than C.albicans (P = 0.03.) There were no significant differences in virulence factors among species. A strong positive correlation was found between proteinase and lipase activity (r = 0.90, P < 0.0001), and between hydrophobicity and biofilm (R = 0.81, P < 0.0001.) CONCLUSIONS: Our results indicate that OC Candida isolates exhibited a significant higher attributes of virulence than other lesions fungus isolates, providing evidence about the association between Candida pathogenicity and lesions severity.

Oral ecosystem alterations in celiac children: a follow-up study.

OBJECTIVE: The aims of this work were (1) to assess the oral health status of children with celiac disease (CD) with or without compliance with a gluten-free diet and in non-celiac children in a follow-up study and (2) to identify oral ecosystem changes that could be used as non-invasive monitoring methods for CD patients. STUDY DESIGN: An 18-month follow-up study in children of both genders, who were 4-12 years old during the study period, was performed. Decayed-missing-filled in temporary (dmft) and permanent teeth (DMFT), enamel alterations, oral hygiene, and gingival index were measured. Oral smears were collected by brushing. Flow rate, calcium, phosphate, pH, buffer capacity, fluoride, and Ca/P ratio were measured in saliva. Salivary protein profiles were performed. RESULTS: Most CD patients (80%) presented typical symptoms between 12 and 24 months old. Children with CD had a significantly low frequency of enamel alterations (30%) (p=0.0001). A high percentage of patients (63.15%) reported having had aphthous ulcers at several times. The celiac group showed significantly more polymorphonuclear neutrophils (PMNs) in smears (20% PMNs per area, p=0.0459) than the control group (0% PMNs per area) at baseline. In CD children, 90% of the samples that showed PMNs at baseline did not present them after 18 months. However, 10% of the smears of CD patients presented PMNs at the end of this study. Compliance with the gluten-free diet was controlled to detect the maintenance or worsening of signs and symptoms during the medical controls. CONCLUSIONS: The main differences amongst CD children who did or did not comply with a gluten-free diet and control children are the presence of PMNs in oral mucosa and protein salivary patterns; these findings could be considered as markers for CD, in conjunction with other signs and symptoms.

Antifungal and post-antifungal effects of chlorhexidine, fluconazole, chitosanand its combinations on Candida albicans

Objective: The aim of this work was to assess the antifungal and post-antifungal effects of chlorhexidine, fluconazole,chitosan and its combinations on virulence factors of Candida albicans. Study Design: Ten isolated strains of Candida albicans obtained from 10 patients with oral candidiasis and acollection strain of C. albicans were treated with antifungal agents in different concentrations or combinationsof them. Virulence factors analyzed were the cell surface hydrophobicity, the germinative tube development, the phospholipase activity and the post-antifungal effect of that exposure. Results: Virulence factors of the isolated strains obtained from patients together with the collection strain showed significant decreases with the different antifungal treatments, except for hydrophobicity and phospholipase activity.The development of germinative tube was the most sensitive factor to all the antifungal agents used. Untreated strains as well as the ones treated with antifungal agents showed a positive correlation among the virulence factorsanalyzed. No synergic effects arose from the combinations of the used drugs. Conclusions: C. albicans isolated strains from patients showed high phospholipase activity and germinative tubeproduction, which corroborates their capacity to infect the oral mucosa and the high prevalence of species. Asa whole, our results imply that short exposures to sub-inhibitory concentrations of the antifungal agents underanalysis, isolated or combined, can modulate the way virulence factors get manifested, thus decreasing their pathogenicity (AU)

Antifungal and post-antifungal effects of chlorhexidine, fluconazole, chitosan and its combinations on Candida albicans.

OBJECTIVE: The aim of this work was to assess the antifungal and post-antifungal effects of chlorhexidine, fluconazole, chitosan and its combinations on virulence factors of Candida albicans. STUDY DESIGN: Ten isolated strains of Candida albicans obtained from 10 patients with oral candidiasis and a collection strain of C. albicans were treated with antifungal agents in different concentrations or combinations of them. Virulence factors analyzed were the cell surface hydrophobicity, the germinative tube development, the phospholipase activity and the post-antifungal effect of that exposure. RESULTS: Virulence factors of the isolated strains obtained from patients together with the collection strain showed significant decreases with the different antifungal treatments, except for hydrophobicity and phospholipase activity. The development of germinative tube was the most sensitive factor to all the antifungal agents used. Untreated strains as well as the ones treated with antifungal agents showed a positive correlation among the virulence factors analyzed. No synergic effects arose from the combinations of the used drugs. CONCLUSIONS: C. albicans isolated strains from patients showed high phospholipase activity and germinative tube production, which corroborates their capacity to infect the oral mucosa and the high prevalence of species. As a whole, our results imply that short exposures to sub-inhibitory concentrations of the antifungal agents under analysis, isolated or combined, can modulate the way virulence factors get manifested, thus decreasing their pathogenicity.

Evaluation of clinical dental variables to build classifiers to predict celiac disease.

OBJECTIVE: The aim of this study was to evaluate the use of salivary variables to build statistical models for predicting celiac disease in symptomatic children. MATERIALS AND METHODS: The study group consisted of 52 children with celiac disease diagnosed by bowel biopsy, grade III or IV (4 to 12 years old, both sexes) and 23 healthy children as a control group. A logistic regression model was applied to evaluate an individual's belonging to one group or another. The performance of the model was evaluated by the value of area under the ROC curve. The salivary variables included in the model were the concentration of total proteins, calcium, Ca/P molar ratio, buffer capacity and salivary flow. RESULTS: The total proteins (p = 0.0016) and Ca/P molar ratio (p = 0.0237) variables were significantly associated with the celiac condition. The value of the area under the ROC curve, estimated from the probabilities of the logistic model, showed that salivary component values allow the celiac condition of patients to be predicted with 85% accuracy (p <0.0001). CONCLUSION: Logistic discriminant analysis built with salivary variables shows that these are good for predicting this eating pathology with 85% accuracy.

Evaluation of clinical dental variables to build classifiers to predict celiac disease

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Objective: The aim of this study was to evaluate the use of salivary variables to build statistical models for predicting celiac disease in symptomatic children. Materials and Methods: the study group consisted of 52 children with celiac disease diagnosed by bowel biopsy, grade III or IV (4 to 12 years old, both sexes) and 23 healthy children as a control group. A logistic regression model was applied to evaluate an individual’s belonging to one group or another. The performance of the model was evaluated by the value of area under the ROC curve. The salivary variables included in the model were the concentration of total proteins, calcium, Ca / P molar ratio, buffer capacity and salivary flow.Results: The total proteins (p = 0.0016) and Ca / P molar ratio (p = 0.0237) variables were significantly associated with the celiac condition. The value of the area under the ROC curve, estimated from the probabilities of the logistic model, showed that salivary component values allow the celiac condition of patients to be predicted with 85% accuracy(p <0.0001). Conclusion: Logistic discriminant analysis built with salivary variables shows that these are goodfor predicting this eating pathology with 85% accuracy

Efecto del quitosán de alto peso molecular y del alginato de sodio sobre la hidrofobicidad y adhesión de Candida albicans a células / Effect of the high molecular weight chitosan and sodium alginate on Candida albicans hydrophobicity and adhesion to cells

Objetivo: Evaluar el efecto del quitosán de alto peso molecular (QAPM) y del alginato de sodio (NaAL) sobre la hidrofobicidad superficial de Candida albicans y la adhesión de esta levadura a células epiteliales y fibroblastos de distinto origen. Diseño del estudio: Para el estudio de la hidrofobicidad, las levaduras (n=7) se hicieron crecer en agar glucosado de Sabouraud suplementado con QAPM o NaAL o en ausencia de los mismos (controles). La determinación de la hidrofobicidadse realizó por el método de adhesión a hidrocarburos utilizando dos solventes orgánicos (xileno y cloroformo). En los estudios de adhesión, las levaduras se pusieron en contacto con soluciones de biopolímeros y luego se enfrentaron a diferentes células (fibroblastos humanos y de rata y células epiteliales Hep-2). La cuantificación se realizó por microscopía óptica.Resultados: Se observó una disminución del 44% de la hidrofobicidad en presencia de QAPM y del 82%, con NaAL, o del 30% con QAPM y 19% con NaAL, cuando los solventes orgánicos empleados fueron cloroformo o xileno, respectivamente. La adhesión de C. albicans a células epiteliales y fibroblastos humanos disminuyó significativamente con ambos biopolímeros. En el caso de los fibroblastos de encía de rata, sólo se observó una disminución con NaAL. En ninguno de los experimentos se observaron diferencias significativas en asociación al tipo de fibroblasto empleado. Conclusiones: Los biopolímeros resultaron efectivos en la reducción de la hidrofobicidad y la adhesión de C. albicans a células, las cuales son importantes factores de virulencia relacionados con la colonización de los tejidos blandos del hospedador o superficies acrílicas presentes en el sistema estomatognático

The aim of the present paper is to evaluate the effect of the high molecular weight chitosan (HMWC) and of sodium alginate (NaAL) on surface hydrophobicity of Candida albicans and on adhesion of the yeast to epithelial cells and fibroblasts of different proceeding.For this study, a collection strain and seven isolates of C. albicans from saliva (patients with denture stomatitis) were grown in Sabouraud glucose agar supplemented with HMWC or NaAL or in absence of them (control). Hydrophobicity was determined by adhesion to hydrocarbons method using two organic media (xylene and chloroform). For adhesion experiments, aqueous suspensions of yeasts were contacted with solutions of biopolymers and different cells (rat and human fibroblasts and epithelial cells Hep-2). The quantification of adhesion was made by optical microscopy.Results: a decrease in hydrophobicity was observed in the presence of HMWC (44%) and of NaAL (82%) when chloroformwas employed as organic medium, meanwhile the decreases were of 30% with HMWC and 19% with NaAL in the presence of xylene. Adhesion of C. albicans to epithelial cells and human fibroblasts decreased significantly with both biopolymers. In the case of rat fibroblasts, a decrease was observed only with NaAL. None of experiments showed significant differences associated to fibroblast type.Conclusions: biopolymers showed effectiveness in reducing hydrophobicity and adhesion of C. albicans to cells, which are important virulence factors related to colonization of the soft tissues of host or acrylic surfaces present in the oral system

Effect of the high molecular weight chitosan and sodium alginate on Candida albicans hydrophobicity and adhesion to cells.

UNLABELLED: The aim of the present paper is to evaluate the effect of the high molecular weight chitosan (HMWC) and of sodium alginate (NaAL) on surface hydrophobicity of Candida albicans and on adhesion of the yeast to epithelial cells and fibroblasts of different proceeding. For this study, a collection strain and seven isolates of C. albicans from saliva (patients with denture stomatitis) were grown in Sabouraud glucose agar supplemented with HMWC or NaAL or in absence of them (control). Hydrophobicity was determined by adhesion to hydrocarbons method using two organic media (xylene and chloroform). For adhesion experiments, aqueous suspensions of yeasts were contacted with solutions of biopolymers and different cells (rat and human fibroblasts and epithelial cells Hep-2). The quantification of adhesion was made by optical microscopy. RESULTS: A decrease in hydrophobicity was observed in the presence of HMWC (44%) and of NaAL (82%) when chloroform was employed as organic medium, meanwhile the decreases were of 30% with HMWC and 19% with NaAL in the presence of xylene. Adhesion of C. albicans to epithelial cells and human fibroblasts decreased significantly with both biopolymers. In the case of rat fibroblasts, a decrease was observed only with NaAL. None of experiments showed significant differences associated to fibroblast type. CONCLUSIONS: Biopolymers showed effectiveness in reducing hydrophobicity and adhesion of C. albicans to cells, which are important virulence factors related to colonization of the soft tissues of host or acrylic surfaces present in the oral system.

Estado de salud bucodental de escolares residentes en localidades abastecidas con agua de consumo humano de muy alto y muy bajo contenido de fluoruros / State of oral health among schoolchildren living in towns supplied with drinking water containing very high and very low levels of fluoride

Descreve e analisa os resultados de uma pesquisa epidemiológica de corte transversal destinada a avaliar o estado de saúde buco-dental de escolares de 6-7 e 12-13 anos, residentes em Sampacho e Porteña, duas localidades da Província de Córdoba (Argentina), abastecidas com água potável contendo quantidade de F- muito diferentes. Em Sampacho, o nível de F- é de 9,05 mg/l enquanto que em Porteña a concentraçäo é de 0,19 mg/l. A proporçäo de escolares (6-7 e 12-13 anos) que näo apresentaram cárie foi significativamente maior em Sampacho do que em Porteña, enquanto, que os índices ceo-d, ceo-s, CPO-D e CPO-S resultaram consideravelmente mais altos nesta última localidade. A severidade da doença de cárie nas crianças de 12-13 anos de Sampacho esteve compreendida entre as categorias baixa e moderada (CPO-D = 2,53), enquanto que em suas similares em Porteña atingiu o grau de moderada e alta (CPO-D=4,41). Näo se registrou nenhum caso de fluorose dental em Porteña enquanto que em Sampacho houve uma alta proporçäo de crianças que apresentou fluoroses leve (6-7 anos) e leve ou intensa (12-13 anos). Os níveis salivares de cálcio, fosfatos, tiocianato, proteínas totais e lg A secretora foram muito similares nos escolares de ambas localidades, e também entre crianças com diferentes tipos de cárie e diferentes graus de gravidade de fluorose. Conclui ser necessária a aplicaçäo de medidas sanitárias urgentes (preventivas ou curativas) para reduzir ou controlar as doenças de cárie em Porteña e a fluorose dental em Sampacho

Condición socioeconómica, salud bucodental y factores asociados en la población infantil (5 años) de la ciudad de Córdoba, Argentina / Socio-economic status, oral health and related factors in a child population (5 years old) of the Cordoba city, Argentina

Se exponen e interpretan los resultados de una investigación referida al estado de salud bucodental de preescolares (5 años) de la ciudad de Córdoba (Argentina). El 95,8 por ciento de los niños del nivel económico social más alto (NES I) tenía un ceo-d menor o igual que el percentilo 80 de la población infantil, mientras que en la categoría socioeconómica más baja (NES III) sólo el 66,9 por ciento de los niños no excedía ese valor. Las superficies oclusales de los molares fueron las que presentaban mayor experiencia de caries, aunque la enfermedad se inició preferentemente en el segundo molar superior (NES I) y en el segundo molar inferior (NES III). El consumo de golosinas incrementó la frecuencia de caries en los niños de los NES I y II, no así en los del NES III. La práctica del cepillado y del control odontológico tuvieron muy poco efecto sobre la salud bucodental. Las concentraciones salivales de calcio, fosfatos, proteínas totales, glucoproteínas e IgA secretoria resultaron casi idénticas en todos los niveles socioeconómicos y no estuvieron relacionadas con la experiencia de caries