MicroRNAs en tejido de cordón umbilical y su relación con el peso al nacimiento

Abstract

Intrauterine growth is a multifactorial process resulting from the interaction between the mother, placenta, fetus, and environmental factors. Birth weight is a key indicator of perinatal health, associated with both short- and long-term complications. In this context, microRNAs (miRNAs), essential epigenetic regulators of gene expression at the post-transcriptional level, may play a crucial role in birth weight alterations. The main objective of this study was to analyze the relationship between miRNA expression in umbilical cord tissue and birth weight. The study included 68 newborns classified into three groups: small for gestational age (SGA, n=10), large for gestational age (LGA, n=28), and controls with appropriate weight for gestational age (AGA, n=30). Umbilical cord tissue samples were collected immediately after delivery, frozen, and subsequently analyzed through massive sequencing and bioinformatics. The analysis identified significant differences in the expression of 41 miRNAs across the groups. SGA newborns showed overexpression of miR-9-3p and miR-324-3p and underexpression of miR-1307-3p compared to AGA controls. In the LGA group, decreased expression of miR-99b-3p, miR-101-3p, miR-125a-3p, among others, and increased expression of miR-455-3p and miR-574-3p were observed. Direct comparison between SGA and LGA groups revealed dysregulation of miRNAs such as miR-324-3p, miR-6750-5p, miR-3919, and miR-5009-3p. These miRNAs are associated with metabolic pathways involved in insulin resistance and diabetes mellitus. In conclusion, this study demonstrates that differential miRNA expression in umbilical cord tissue is linked to birth weight. The findings suggest that epigenetic alterations from the neonatal period may predispose individuals to the development of chronic metabolic diseases later in life.