A Brain Anti-Senescence Transcriptional Program Triggered by Hypothalamic-Derived Exosomal microRNAs.

In contrast to the hypothesis that aging results from cell-autonomous deterioration processes, the programmed longevity theory proposes that aging arises from a partial inactivation of a "longevity program" aimed at maintaining youthfulness in organisms. Supporting this hypothesis, age-related changes in organisms can be reversed by factors circulating in young blood. Concordantly, the endocrine secretion of exosomal microRNAs (miRNAs) by hypothalamic neural stem cells (htNSCs) regulates the aging rate by enhancing physiological fitness in young animals. However, the specific molecular mechanisms through which hypothalamic-derived miRNAs exert their anti-aging effects remain unexplored. Using experimentally validated miRNA-target gene interactions and single-cell transcriptomic data of brain cells during aging and heterochronic parabiosis, we identify the main pathways controlled by these miRNAs and the cell-type-specific gene networks that are altered due to age-related loss of htNSCs and the subsequent decline in specific miRNA levels in the cerebrospinal fluid (CSF). Our bioinformatics analysis suggests that these miRNAs modulate pathways associated with senescence and cellular stress response, targeting crucial genes such as Cdkn2a, Rps27, and Txnip. The oligodendrocyte lineage appears to be the most responsive to age-dependent loss of exosomal miRNA, leading to significant derepression of several miRNA target genes. Furthermore, heterochronic parabiosis can reverse age-related upregulation of specific miRNA-targeted genes, predominantly in brain endothelial cells, including senescence promoting genes such as Cdkn1a and Btg2. Our findings support the presence of an anti-senescence mechanism triggered by the endocrine secretion of htNSC-derived exosomal miRNAs, which is associated with a youthful transcriptional signature.

Prevalencia de hipertensión arterial en alumnos de 4° básico a 1° medio en un colegio de Santiago (Chile) / Prevalence of hypertension in students of 4th grade to 9th grade in a school in Santiago (Chile)

Objetivo: Determinar el comportamiento de la presión arterial en niños de 9 a 16 años y comprobar si existe asociación entre la presencia de HTA con diversos factores considerados como posibles riesgos por la literatura. Material y método: Estudio de tipo no experimental, exploratorio, descriptivo y transversal. La muestra estuvo constituida por 109 alumnos de ambos sexos. La variable "presión arterial" se obtuvo mediante la técnica estandarizada de medición de presión arterial del Ministerio de Salud de Chile en dos ocasiones. Resultados: Se observaron alteraciones de la presión arterial en el 19,6 % del total con una cantidad de cuatro niños hipertensos, equivalente al 3,6 %. Discusión y conclusiones: No se encontró asociación entre los factores de riesgo estudiados y la HTA; lo anterior podría atribuirse a que probablemente estos factores actúan a largo plazo. Los datos sobre colesterol fueron obtenidos mediante una ficha encuesta, no por medio de exámenes de laboratorio, ya que la muestra obtenida fue pequeña. La presencia y riesgo de HTA en niños revela una debilidad en la pesquisa de esta y sugiere la necesidad de implementar normas para la obligatoriedad de la medición de presión arterial en el control de niño sano.

Objective: High Blood Pressure (BP) is one of the principal cardiovascular risks. Nevertheless, it is not included in the physical examination of people younger than 15 years old, which does not allow high BP early detection. The aim of the study is to determine the presence of elevated arterial blood pressure in children's from 9 to 16 years old, and to verify if there exists an association with risk factors considered by literature. Materials and methods: Non-experimental, exploratory, descriptive and transversal study. The sample consisted of 109 children of both sexes. The arterial pressure was obtained through the standardized measurement of arterial blood pressure of the Chilean ministry of health in two occasions. Results: Alterations of the arterial blood pressure were detected in 19,6% of the children, with 4 children's presenting high BP, equivalent to 3,6%. Discussion and conclusions: There was no association between the studied risk factors and the high BP. This might be attributed to the fact that the studied factors operate in the long term, cholesterol data were obtained through a survey, not through laboratory tests and the obtained sample was small. The presence and risk of high BP in children reveal a weakness in its screening and suggest including measurement of arterial blood pressure as an obligation in children's health controls.