Chemical contaminant linked to obesity in mice

Food chain contaminant tributyltin (TBT) causes transgenerational obesity in mice, according to researchers in California, suggesting it could raise similar concerns to Bisphenol A (BPA).

The latter has been linked to the development of medical complaints and diseases ranging from obesity to various cancers.

TBT is a non-intentionally-added substance (NIAS) found in PVC plastics. Writing in the monthly peer-reviewed journal Environmental Health Perspectives, the scientists claim TBT influences the build up of fat in mice two or three generations removed from those exposed to it.

Earlier work

The assertion builds on earlier work from the same researchers indicating TBT exposure modulates critical steps in fat building and that prenatal TBT exposure predisposes certain mouse stem cells to become fat cells.

The latest paper outlines an experiment exposing female mice to a dimethyl sulfoxide vehicle, the pharmaceutical obesogen rosigilitazone or three doses of TBT throughout pregnancy via drinking water.

Mice initially exposed in utero were bred to yield a second generation and effects were studied on a third generation bred from the second.

Effects studied

Fat depot weights, fat cell number and size, cell programming, build up of fat in the liver and liver gene expression in all three generations was studied.

The paper states prenatal TBT exposure increased most white fat tissue, depot weights, fat cell size and number and the predisposition of the stem cells to produce fat at the expense of bone.

“Prenatal TBT exposure produced transgenerational effects on fat depots and induced a phenotype resembling non-alcoholic fatty liver disease through at least the F3 [third] generation,” the scientists conclude. “These results show that early life obesogen exposure can have lasting effects.”

Source: 'Transgenerational inheritance of increased fat depot size, stem cell reprogramming and hepatic steatosis elicited by prenatal obesogen tributyltin in mice'; Environmental Health Perspectives; January 15, 2013; doi: http://dx.doi.org/10.1289/ehp.1205701 Authors: Raquel Chamorro-García, Margaret Sahu, Rachelle Abbey, Jhyme Laude and Nhieu Pham (Department of Developmental and Cell Biology, University of California, Irvine, California) and Bruce Blumberg (also with Department of Pharmaceutical Sciences, University of California, Irvine, California).