Relação entre obesidade e infecção por Ancylostoma ceylanicum em modelo experimental

• Ano de defesa: 2017
• Autor(a) principal: Vivian Jordania da Silva
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Minas Gerais; Brasil; ICB - INSTITUTO DE CIÊNCIAS BIOLOGICAS; Programa de Pós-Graduação em Parasitologia; UFMG
• Palavras-chave em Português: Obesidade; Ancilostomídeos; Ancylostoma ceylanicum; Dieta HSB; Marcadores clínicos; Parasitologia; Ancilostomíase; Infecção
• Link de acesso: http://hdl.handle.net/1843/34761

Obesity and hookworm are considered public health problems. While ancylostomiasis is prevalent in tropical and subtropical regions, affecting mainly the poorest population, obesity has grown significantly, affecting all social classes, and regardless of the climate. Recent studies have shown that infection by intestinal helminths in obese individuals is able to ameliorate metabolic disorder by improving glucose tolerance, decreasing both, insulin resistance and lowintensity inflammation. This decrease in morbidity would be related to the ability of some helminths to stimulate IL-10 production, proliferation of regulatory T cells, and polarization of the Th2-type response, since obesity is characterized by the predominance of an inflammatory Th1 response. However, few helminth species have been studied in this context, and some modulators mechanisms still require further studies. Therefore, the present work aimed to investigate the role of the experimental infection by Ancylostoma ceylanicum in the modulation of the immune response in an obese experimental model. In the experimental design, groups of six female hamsters submitted to a hyperlipidic and hypercaloric diet (HSB), were used to induce obesity, both infected and uninfected, and were compared to normonourished controls, uninfected and infected with 50 larvae of A. ceylanicum. Biochemical, hematological and immunological parameters were evaluated. The infected animals were submitted to parasitological examinations and the organs were collected for quantification of cytokines by qRT-PCR and immunoenzymatic tests. The results showed that A. ceylanicum infection accentuated weight loss in obese animals with greater intensity compared to normonourished, worsening the clinical condition of the host. On the other hand, obesity decreased the recovery of worms and the ovoposition of females, possibly due to the greater inflammation in the intestines of these animals. In addition, both infected groups, had decreased levels of hemoglobin, albumin, iron and erythrocytes. The infection interfered in lipid metabolism, increasing total cholesterol and triglyceride levels in the obese group and causing a decrease in HDL levels in both groups. Obesity led to an increase in glucose levels, and the infection caused glucose increase in both, the normonourished and obese groups. Inflammation was intensified in obese animals that showed elevated macrophage and neutrophil activation in adipose tissue, enlargement of the spleen and accumulation of lipids in the liver and faeces. The infection also caused a decrease in the levels of IL-10, FoxP3 and IL-2 and obesity caused elevation in IFN- γ levels. The present work has raised the hypothesis that A. ceylanicum infection could interfere with the obesity situation, improving the biochemical parameters associated with this pathogenesis. However, the results showed a negative correlation between the two diseases to the host, that is, the association of obesity with A. ceylanicum infection worsened the clinical condition of the host. Despite the decrease in IFN-γ levels, the infection did not potentiate the expression of the transcription factor Foxp3, IL-10 and IL-2; markers that could positively mediate the damage caused by obesity to the host. In addition, parameters associated with lipid and glucose metabolism were aggravated by infection as well as inflammation.