Determinación del efecto de la deficiencia de vitamina A sobre la homeostasis del hierro y su estado en modelo murino

Abstract

Iron deficiency anemia (IDA) and vitamin A deficiency (VAD) belong to the micronutrient deficiencies defined by the WHO as worldwide concern. In Colombia, IDA prevalence for children from 1 to 4 years old is 14.8% and anemia is 24.7% for children from 6 to 59 months old, it is remarkable in a country where is mandatory to fortify wheat flour with iron since 1996. On the other hand, VAD prevalence for children from 1 to 4 years old is 27.3% and, in this case, there is no mandatory fortification programs in the country. Interactions between micronutrients are not unknown on health and nutrition field, the most recognized is that between calcium and vitamin D; besides, there is evidence from an epidemiological perspective that VAD and ID are linked in some way, fact supported for some studies using cellular and animal models. This study has the hypothesis that vitamin A regulates in some way the iron homeostasis and its metabolic role, and has three approaches: weight gain, biochemical and hematological parameters and molecular markers of iron homeostasis. We designed a study with four experimental diets with different ratios of iron and vitamin A (sufficient, insufficient and deficient) and a control diet with a sufficient supply of both micronutrients. The quantity of animals was calculated statistically giving seven animals per group for 35 animals. The rats started the experiment at weaning (21 days-old) and received food and water at libitum for six weeks, during this time food intake and weight were recorded each week. At sixth week the animals were euthanized and samples from blood and tissues of interest (liver, spleen and duodenum) were taken for analysis of biochemical and hematological indicators in blood and PCR and Western Blot test in tissues for the analysis of hepcidin, ferritin, transferrin receptors, transferrin and interleukin-6 as proteins of interest.

La anemia por deficiencia de hierro (IDA) y la deficiencia de vitamina A (VAD) hacen parte del grupo de las deficiencias por micronutrientes definidas por la OMS como de interés mundial. En el caso de Colombia, la prevalencia de IDA en niños de 1 a 4 años es de 14.8% y la anemia está en 24.7% para niños entre 6 y 59 meses, algo paradójico si se tiene en cuenta que desde 1996 es obligatorio fortificar la harina de trigo con hierro. De otro lado, la prevalencia de VAD es de 27.3% para el mismo grupo poblacional, en este caso hasta el día de hoy no existe ningún tipo de fortificación obligatoria en el país. Las interacciones entre nutrientes no son algo desconocido en el campo de la salud y la nutrición, la más reconocida es la existente entre calcio y vitamina D; además, existe evidencia desde el punto de vista epidemiológico de que la VAD y la ID tienen algún tipo de relación, hecho que ha sido soportado por algunos estudios en modelos celulares y animales. Este estudio parte de la hipótesis de que la vitamina A regula de alguna forma la homeostasis del hierro y su rol metabólico, y aborda tres enfoques: ganancia de peso, parámetros bioquímicos y hematológicos y biomarcadores de la homeostasis del hierro.