HOUSTON, Oct. 25, 2010 Some unexpected effects of lead exposure that may one day help prevent and reverse blindness have been uncovered by a University of Houston (UH) professor and his team.
Donald A. Fox, a professor of vision sciences in UH's College of Optometry (UHCO), described his team's findings in a paper titled "Low-Level Gestational Lead Exposure Increases Retinal Progenitor Cell Proliferation and Rod Photoreceptor and Bipolar Cell Neurogenesis in Mice," published recently online in Environmental Health Perspectives and soon to be published in the print edition of the prestigious peer-reviewed journal.
The study suggests that lead, or a new drug that acts like lead, could transform human embryonic retinal stem cells into neurons that would be transplanted into patients to treat retinal degenerations.
"We saw a novel change in the cellular composition of the retina in mice exposed to low levels of lead during gestation. The retina contained more cells in the rod vision pathway than normal or than we expected," said Fox, who also is a professor of biology and biochemistry, pharmacology and health and human performance. "The rod photoreceptors and bipolar cells in this pathway are responsible for contrast and light/dark detection. These new findings directly relate to the supernormal retinal electrophysiological changes seen in children, monkeys and rats with low-level gestational lead exposure."
Fox said these effects occur at blood lead levels at or below 10 micrograms per deciliter, the current low-level of concern by the Centers for Disease Control and Prevention. Because the effects occur below the "safe level," Fox says it raises more questions about what should be considered the threshold level for an adverse effect of lead on the brain and retina.
Fox has studied lead toxicity for 35 years, specifically as it relates to its effects on the brain and retina of children. His interest in g
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University of Houston