Polybrominated diphenyl ethers (PBDEs), chemicals used as fire retardants are commonly found in numerous household items, such as the television, computer, toaster, the sofa, and are now present, in alarming concentrations, in human blood and breast milk. The research of Dr. Margarita Currás-Collazo, associate professor of cell biology and neuroscience at UC Riverside, delineating some of the potential human health consequences of PBDEs, was recently featured in a KNBC news story about household PBDE exposure.
Currás-Collazo and Cary Coburn, a doctoral student in environmental toxicology and part of Currás-Collazo's research team, were interviewed for the KNBC story regarding their research on the physiological and neurological effects of PBDEs in mammalian systems. Using rat tissue, their work shows that PBDEs disrupt mechanisms responsible for releasing hormones in the body. Moreover, their research demonstrates that, like polychlorinated biphenyls (PCBs), PBDEs alter calcium signaling within nerve cells of the brain - a critical mechanism for transmitting information between and within brain cells, for learning and memory, and for regulating the release of hormones in the body. "Long-term exposures to PBDEs may pose a human health risk, especially to infants and toddlers who are more likely to ingest household dust or acquire these chemicals through mother's milk," said Currás-Collazo.
The research on PCBs and now PBDEs is one outcome of a long-standing collaboration of Currás-Collazo and Coburn with Dr. Martha León-Olea, who heads the division of neurosciences at the Instituto Nacional de Psiquiatria in Mexico City. With the support of 2002 and 2006 UC MEXUS-CONACYT collaborative grants, National Science Foundation funding and in collaboration with Prasada Rao S. Kodavanti, a senior toxicologist at the U.S. Environmental Protection Agency, this binational research team has undertaken research on the potential causal effects of PCB and PBDEs, originating in indoor and outdoor air as well as grocery foods, on brain and cardiovascular function.
In a paper soon to be published in Neurochemical Research, Currás-Collazo and Coburn, in collaboration with Kodavanti, show that the regulation of calcium in neurons can be compromised by PBDEs and PCBs. The article is now available online here. This summer, the three researchers reported in Toxicological Sciences that PBDEs, like PCBs, can disrupt the neuroendocrine system, which regulates the secretion of hormones such as those responsible for body water regulation and cardiovascular function.
PBDEs closely resemble the molecular structure of PCBs and as such are highly stable organic compounds that persist in the environment. However, while the manufacture of PCBs in the U.S. was discontinued in 1977, the use of PBDEs continues to rise. They currently are being produced for use as flame-retarding compounds in a variety of consumer goods, including electrical appliances, building materials and upholstery furnishings. PBDEs mobilize into the indoor air and household dust from household goods, resulting in humans and pets getting exposed continuously to these toxicants. Over time, PBDEs, PCBs and similar organic toxicants leach into the environment when household wastes decompose in landfills or are incompletely incinerated. They are now found in air, water and soil as well as in fish, birds, marine mammals and humans.
Currás-Collazo notes that, "due in part to our lifestyles - electronic equipment, car and airplane travel, computers - PBDEs bioaccumulate, increasing their concentration in human and animal tissues over time. They are difficult to get rid of, persisting in the environment and in our bodies." Currás-Collazo, León-Olea, and Coburn continue to study the mechanisms of PCB toxicity as part of their 2006 UC MEXUS-CONACYT collaborative grant, "Derangement of the hypothalamo-neurohypophysial system by polychlorinated biphenyls as a causal factor for the development of high blood pressure." The long-term goal of their collaboration and multiple avenues of research is to uncover the mechanisms of action of PBDEs and of their additional effects on physiology and neurological function and development.
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