Estudios de las diferencias en invasión de células epiteliales y resistencia al sistema del complemento entre los serotipos b y c de "Aggregatibacter Actinomycetemcomitans
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Fecha
2010
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Profesor/a Guía
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es
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Universidad Andrés Bello
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Licencia CC
Licencia CC
Resumen
Las enfermedades periodontales asociadas a la placa dental son un grave
problema de salud pública, tanto en nuestro país como en todo el mundo. Las
manifestaciones clínicas de esta enfermedad pueden ser agrupadas bajo la
denominación de gingivitis y periodontitis, siendo esta última la forma más grave
de la enfermedad.
La enfermedad periodontal se define como un conjunto de alteraciones que
afectan a los tejidos que dan soporte y otorgan protección al diente, como ligamento
periodontal, encía y hueso alveolar. La etiología de la enfermedad se ha atribuido a
bacterias específicas presentes en la placa dental, que bajo ciertas condiciones
aumentarían en número y proporción dentro de la placa en un individuo
susceptible. Una de estas bacterias, Aggregatibacter actinomycetemcomitans (Aa), ha
sido fuertemente asociada a la forma más grave de la enfermedad, la periodontitis
agresiva.
Actualmente, se han descrito 6 serotipos distintos de Aa (a-f), basados en
diferencias en el antígeno O del lipopolisacárido (LPS), donde el b corresponde al
serotipo aislado con mayor frecuencia desde personas enfermas y el e desde
personas sanas. Sin embargo, las últimas publicaciones al respecto de la clasificación
de Aa, han descrito importantes diferencias en virulencia en cepas del mismo
serotipo.
En este trabajo se aislaron cepas clínicas de los serotipos b y e se les
caracterizó genéticamente, a partir de los genes de virulencia lkt, jlp-1 y cdt.
Posteriormente, las cepas fueron evaluadas en su habilidad de adherirse, invadir y
proliferar en células HEp-2 y fibroblastos gingivales humanos. Además, se analizó la
capacidad de los distintos aislados de resistir la acción del sistema del complemento.
Los resultados demostraron que el serotipo de Aa no es el factor más
relevante en la resistencia al sistema del complemento e interacción con células
epiteliales. La procedencia de las cepas y las diferencias en los promotores de los
genes de virulencia otorgan importantes variaciones en la virulencia de las distintas
cepas analizadas
Periodontal disease associated with dental plaque are a majar public health problem in our country and around the world. The clinical manifestations of this disease can be grouped under the name of gingivitis and periodontitis, the latter being the most serious form of the disease. Periodontal disease is defined as a set of disorders that affect the tissues which provide support and protection to the tooth, like periodontal ligament, gingivia and alveolar bone. The etiology of the disease has been attributed to a group of specifics bacteria present in the plaque, which under certain conditions way increase in number and proportion within the plaque in a susceptible host. One of these bacteria, Aggregatibacter actinomycetemcomitans (Aa) has been strongly associated with the more severe disease, aggressive periodontitis. Currently, it has been described 6 different serotypes of Aa (a-f), based on differences in the O antigen of lipopolysaccharide (LPS), where b corresponds to the serotype most frequently isolated from sick people and serotype c from healthy people. Nevertheless, the later publications about the classification of Aa, have described significant differences in virulence among strains of the same serotype. In this work were isolated clinical strains of serotypes b and c, which have been characterized genetically by virulence genes 1kt, flp-1 and cdt. Subsequently, the strains were evaluated on their ability to adhere, invade and proliferate in HEp-2 cells and human gingival fibroblasts. In addition, we analyzed the ability of the different isolates, to resist the lytic action of the complement system. The results showed that the Aa serotype is not the most important factor in resistance to the complement system and interaction with the epitelial cells. The origin of the strains and differences in the promoters of the virulence genes, provide substantial variation in the virulence of different strains tested.
Periodontal disease associated with dental plaque are a majar public health problem in our country and around the world. The clinical manifestations of this disease can be grouped under the name of gingivitis and periodontitis, the latter being the most serious form of the disease. Periodontal disease is defined as a set of disorders that affect the tissues which provide support and protection to the tooth, like periodontal ligament, gingivia and alveolar bone. The etiology of the disease has been attributed to a group of specifics bacteria present in the plaque, which under certain conditions way increase in number and proportion within the plaque in a susceptible host. One of these bacteria, Aggregatibacter actinomycetemcomitans (Aa) has been strongly associated with the more severe disease, aggressive periodontitis. Currently, it has been described 6 different serotypes of Aa (a-f), based on differences in the O antigen of lipopolysaccharide (LPS), where b corresponds to the serotype most frequently isolated from sick people and serotype c from healthy people. Nevertheless, the later publications about the classification of Aa, have described significant differences in virulence among strains of the same serotype. In this work were isolated clinical strains of serotypes b and c, which have been characterized genetically by virulence genes 1kt, flp-1 and cdt. Subsequently, the strains were evaluated on their ability to adhere, invade and proliferate in HEp-2 cells and human gingival fibroblasts. In addition, we analyzed the ability of the different isolates, to resist the lytic action of the complement system. The results showed that the Aa serotype is not the most important factor in resistance to the complement system and interaction with the epitelial cells. The origin of the strains and differences in the promoters of the virulence genes, provide substantial variation in the virulence of different strains tested.
Notas
Tesis (Bioquímico, Magíster en Bioquímica)
Palabras clave
Células Epiteliales, Virulencia