On Tuesday morning I attended the Symposium Session “Stem Cells and Metals Toxicity: From Tissue Regeneration and Repair to Carcinogenesis.” The presenters covered stem cell function and dysfunction in multiple organ systems, including the muscle, brain, and mammary gland, by means of various in vitro and in vivo model systems. Presentations included stem cell or cancer stem cell responses from exposure to arsenic, methylmercury, manganese, and cadmium.
I particularly enjoyed the presentation by Dr. Fabrisia Ambrosio from the University of Pittsburgh. She discussed how low to moderate arsenic exposure affects muscle stem cell function. Under normal physiology, injury to skeletal muscle results in the proliferation and expansion of the muscle stem cell pool. Myofibroblasts are recruited to sites of injury and lay down an extracellular matrix that allow myotubes to form. The composition of the extracellular matrix is important for proper stem cell function. However, after arsenic exposure, muscle repair is dramatically inhibited. There are fewer myofibers formed and the extracellular matrix that is produced not only is unfavorable for stem cell function but is similar to a phenotype observed in aging muscle.
Understanding the dysregulation of muscle regeneration and repair after arsenic exposure is crucial when we consider that approximately four million people in the United States are drinking water with arsenic levels that exceed the government standard (10 µg/L or 10 ppb). Sadly, over 200 million people worldwide are drinking water with high levels of arsenic, which is known to cause muscle cramping and motor dysfunction. The extracellular matrix and myofibroblasts may represent novel targets for therapeutic intervention following arsenic exposure.
This blog was prepared by an SOT Reporter. SOT Reporters are SOT members who volunteer to write about sessions and events they attend during the SOT Annual Meeting and ToxExpo. If you are interested in participating in the SOT Reporter program in the future, please email Giuliana Macaluso.