Project name: Homo sapiens

Description: Despite the documented benefits of breastfeeding and major governmental advocacy efforts, a paucity of data exists regarding the transfer of most drugs into breast milk. Passive diffusion governs the extent of accumulation for most drugs and the exposure risk can therefore be predicted using mathematical models. However, examples of xenobiotic accumulation into breast milk well above that predicted by passive diffusion have been documented and attributed to drug transport. A thorough evaluation of the expression of xenobiotic transporters in mammary epithelial cells (MECs), the cells that form the anatomical barrier between maternal serum and breastmilk, during lactation is necessary to determine the drugs for which an active transport mechanism governs transfer into breast milk and to improve predictive models.We used microarrays to evaluate gene expression in human mammary epithelial cells and identified xenobiotic trasnporter genes that were upregulated during lactation.Overall design: Mammary epithelial cells were isolated from breast milk provided by nursing women (lactating; n=3) and from surgical breast specimens provided by women undergoing reduction mammoplasty (nonlactating controls; n=3) using fluorescence-activated cell sorting (FACS). RNA was extracted from this highly purified (>99%) cell population and hybridized on Affymetrix microarrays.

Data type: Transcriptome or Gene expression

Sample scope: Multiisolate

Relevance: Medical

Last updated: 2009-09-25