Ingrid Medina is a postdoctoral researcher at the Institute of Environmental Medicine, Unit of Systems Toxicology at Karolinska Institutet.
She obtained the PhD degree in Biomedical Sciences at National Autonomous University of Mexico (UNAM) in 2019 evaluating the toxicity of titanium dioxide nanoparticles after inhalation. Then, she worked for two-years as postdoc evaluating the gastrointestinal toxicity induced by titanium dioxide as food additive.
In 2021 she joined Emma Wincent´s group to study the role of AHR/CYP1-feedback signaling in intestinal barrier homeostasis.
The aryl hydrocarbon receptor (AHR) is a transcription factor that mediates the toxicity of xenobiotics such as dioxins, polychlorinated biphenyls, and polycyclic aromatic hydrocarbons. Although AHR has been well described as a mediator of toxicity, it has recently been shown that AHR is also involved in various physiological functions, particularly in barrier organs such as the skin, lungs, and intestine.
The intestinal epithelium is continuously renewed from crypt stem cells that differentiate into specialized epithelial cells generating the intestinal barrier. The integrity of this intestinal barrier has substantial implications for health even beyond the intestine, and several internal and environmental factors play a significant, but mechanistically poorly understood, role in intestinal homeostasis.
The ongoing project aims to clarify the differential signaling pathways triggered by AHR upon activation by physiological versus xenobiotic ligands, to elucidate the mechanisms underlying the dual role of the AHR in intestinal barrier homeostasis and thereby gastrointestinal toxicity and diseases.
To investigate the role of AHR in the process of crypt stem cell proliferation and differentiation, mouse models as well as intestinal organoid cultures have been developed in collaboration with the research group of Brigitta Stockinger at the Francis Crick Institute.
Food-grade titanium dioxide (E171) induces anxiety, adenomas in colon and goblet cells hyperplasia in a regular diet model and microvesicular steatosis in a high fat diet model. Medina-Reyes EI, Delgado-Buenrostro NL, Díaz-Urbina D, Rodríguez-Ibarra C, Déciga-Alcaraz A, González MI, Reyes JL, Villamar-Duque TE, Flores-Sánchez ML, Hernández-Pando R, Mancilla-Díaz JM, Chirino YI, Pedraza-Chaverri J.Food Chem Toxicol. 2020 Dec;146:111786. doi: 10.1016/j.fct.2020.111786.
Food additives containing nanoparticles induce gastrotoxicity, hepatotoxicity and alterations in animal behavior: The unknown role of oxidative stress. Medina-Reyes EI, Rodríguez-Ibarra C, Déciga-Alcaraz A, Díaz-Urbina D, Chirino YI, Pedraza-Chaverri J.Food Chem Toxicol. 2020 Dec;146:111814
Differences in cytotoxicity of lung epithelial cells exposed to titanium dioxide nanofibers and nanoparticles: Comparison of air-liquid interface and submerged cell cultures. Medina-Reyes EI, Delgado-Buenrostro NL, Leseman DL, Déciga-Alcaraz A, He R, Gremmer ER, Fokkens PHB, Flores-Flores JO, Cassee FR, Chirino YI.Toxicol In Vitro. 2020 Jun;65:104798.
Food-grade titanium dioxide (E171) by solid or liquid matrix administration induces inflammation, germ cells sloughing in seminiferous tubules and blood-testis barrier disruption in mice. Rodríguez-Escamilla JC, Medina-Reyes EI, Rodríguez-Ibarra C, Déciga-Alcaraz A, Flores-Flores JO, Ganem-Rondero A, Rodríguez-Sosa M, Terrazas LI, Delgado-Buenrostro NL, Chirino YI.J Appl Toxicol. 2019 Nov;39(11):1586-1605.