Dr. Alejandra Espinosa Biography

Dr. Alejandra Espinosa E. is Medical Technologist, specialists in clinical chemestry, hematology and blood bank, from University of Chile. In 2003 he obtained a Master’s degree in Biological Sciences, Biochemistry and Molecular Biology at the University of Chile. In 2008 obtained a PhD in Biomedical Sciences from the Faculty of Medicine of the University of Chile. Since 2005 she is Assistant Professor of the Department of Medical Technology of the University of Chile.

Research line

Oxidative stress occurs during the development of obesity and insulin resistance, affecting the physiology of skeletal muscle. NOX2 appears to be the main ROS source under insulin stimulation in skeletal muscle cells.

Espinosa has also established animal model to study metabolic syndrome induced by high fat diet (HFD) in mice, which developing obesity, fatty liver, oxidative stress and insulin resistance at both systemic and muscular levels. Since 2009, this pathological model has been developed as a result of the FONDECYT induction grant titled: “Role of H2O2 in the pathophysiology of Diabetes Mellitus”. The main results of this study showed increased insulin-stimulated H2O2 release decreased reduced-to-oxidized glutathione ratio (GSH / GSSG) in skeletal muscle from obese mice. Hydrogen peroxide generation is higher in muscle fibers than HFD fed mice, in addition to the activation of NOX2, an enzyme that generates superoxide anion, which is converted to H2O2.

Currently, Espinosa is focused in describing the process whereby Physalis peruviana induces prevention and revertion of insulin resistance phenotype induced by obesity.

Selected references

  1. Espinosa A, Henríquez-Olguín C, Jaimovich E. Reactive oxygen species and calcium signals in skeletal muscle: A crosstalk involved in both normal signaling and disease. Cell Calcium (2016) pii: S0143-4160(16)30013-6.
  2. Diaz-Vegas, C.A. Campos, A. Contreras-Ferrat, M. Casas, S. Buvinic, E. Jaimovich, A. Espinosa*. ROS Production via P2Y1-PKC-NOX2 Is Triggered by Extracellular ATP after Electrical Stimulation of Skeletal Muscle Cells. PLoS One (2015) 10, e0129882.
  3. Espinosa A*, Campos C, Diaz-Vegas A, Galgani JE, Juretic N, Osorio-Fuentealba C, et al. Insulin-dependent H2O2 production is higher in muscle fibers of mice fed with a high-fat diet. International journal of molecular sciences. 2013;14(8):15740-54.
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