Influencia de bacterias probióticas en el timo: órgano clave en la respuesta inmune

MALDONADO-GALDEANO, CAROLINA; BALCELLS MARÍA FLORENCIA; CAZORLA, SILVIA INÉS; NOVOTNY NUÑEZ, IVANNA ; MARTÍNEZ MONTEROS, MARÍA JOSÉ; PERDIGÓN, GABRIELA

Congreso; XIX Congreso Latinoamericano de Nutrición (SLAN); 2021

Sociedad Latinoamericana de Nutrición (SLAN)

The immune stimulation by probiotics administered to healthy host, induce a network of signals with activation of the intestinal ephitelial cells(IEC) and the immune cells associated to the lamina propria. These facts are induced both whole bacteria or their cell wall fragments. The signals stimulating the epithelial and the immune cells activate mainly the innate response from the immune cells associated to the intestine with an increase in the release of cytokines, to activate the adaptative response at local and systemic level. Any disease that impairs the balance between energy intake and caloric expenditure, such as malnutrition, will have a direct effect on the immune system, increasing the risk of infections, inflammatory processes and others. The role on health of probiotics, especially lactic acid bacteria are being studied by researchers in worldwide. There are no studies strictly related to the intestinal immunity and functionality of the thymus. The thymus is a primary lymphoid organ present in all vertebrates, it is responsible for the development of self-restricted, self-tolerant, immunocompetent T cells. With the knowledge that probiotics are able to improve the intestinal ecosystem, we focus in the usefulness of these microorganisms in immunodeficient host as malnutrition (under-nourish or obesity) and in elderly host, considering that in old age there is involution of the thymus gland similar to those observed in obesity. We observed in both malnutrition mice models (under nutrition and obesity), and in elderly mice an improvement in the histology of intestine and thymus with an improvements in their functionality The malnourished mice showed a loss of corticomedullary differentiation in the thymus with lobule decreasing compared to the well-nourished animals. These alterations in undernourished and obese mice were reversible after probiotic administration An improvement in the thymus histology was also observed in old mice that received probiotic. Malnutrition produced an increase of the immature double-positive thymocytes (CD4+CD8+) and a decrease in the mature single-positive thymocytes (CD4+CD8-),which was reverted after oral probiotic administration This effect was also observed in old mice.As regard the production of pro/inflammatory cytokines, such as, IFNg, IL6 and TNFa that are increased in malnutrition with a decreasing in IL-10, we observed that mice were given probiotic bacterium, diminished the number of TNFa secreting cells and restoring the values for IFNg and IL-6 secreting cells and with increase in IL10, that is important to regulate the immune response and to maintain the homeostasis in the thymus microenvironment. Similars results were observed in old mice We demonstrated the importance of the axis intestine -probiotic- immune system to maintain thymus functionality and health .