Increased DMT-1 expression in placentas of women living in high-Cd-contaminated areas of Thailand
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Cadmium (Cd) is a toxic heavy metal and contamination was reported in soil and rice in several areas of Thailand. Humans are normally exposed to environmental Cd, leading to gradual Cd accumulation in their bodies, including the placenta. DMT-1 is a divalent metal transporter which is found in placental tissue and plays a vital role in the transportation of Fe2+ and Cd2+. This study investigated DMT-1 protein and mRNA expressions in full term human placentas comparing those from high-Cd-contaminated areas (high-Cd group) and low-Cd-contaminated areas (low-Cd group), n = 6 per group. The maternal blood Cd (B-Cd) and placental Cd (P-Cd) of the high-Cd group was significantly raised in comparison with those in the low-Cd group. DMT-1 in the fetal portion of the placentas was localized in the apical and basal portions of the cytoplasm of the syncytiotrophoblastic cells, the endothelium of fetal capillaries which is functional structure of the placental barrier, and was also found in the cytoplasm of Hofbauer cells. Moreover, DMT-1 localization in the maternal portion was also detected in most decidual cells. In addition, the DMT-1 protein and mRNA expressions in the high-Cd group were significantly higher than those in the low-Cd group. Therefore, we suggest that pregnant women, who are exposed to environmental Cd, show an increased level of Cd in their maternal blood and this Cd can accumulate in the placenta. Intracellular Cd may induce DMT-1 mRNA transcription which further translates into DMT-1 protein, which can then function as a reciprocal Cd transporter in placental tissue.
KeywordsCadmium (Cd) Placenta Divalent metal transporter-1 (DMT-1)
We would especially like to thank all Dr. Witaya Swaddiwudhipong and hospital staffs of Mae Sot General Hospital for research collaboration and sample collection. We are sincerely grateful to Dr. Roger Timothy Callaghan, Mae Fah Lung University for assistance with proof reading. We gratefully express our sincere thanks to Associate Professor Dr. Wattana Weerachatyanukul and his research team (SK, LP and NT) at Faculty of Science, Mahidol University for initiating the Western blot analysis and useful suggestion. Finally, we would like to thank the Faculty of Medical Science, Naresuan University for all facilities provision.
This research is financially supported by the Thailand Research Fund (TRF).
Compliance with ethical standards
All procedures were approved by the Human Ethics Committee of Naresuan University, Thailand (Project No. 50-03-01-0017). All participants gave informed consent to participate in this study.
- Goyer RA, Cherian MG (1992) Role of metallothionein in human placenta and rats exposed to cadmium. IARC Sci Publ 118:239–247Google Scholar
- McKie AT, Marciani P, Rolfs A, Brennan K, Wehr K, Barrow D, Miret S, Bomford A, Peters TJ, Farzaneh F, Hediger MA, Hentze MW, Simpson RJ (2000) A novel duodenal iron-regulated transporter, IREG1, implicated in the basolateral transfer of iron to the circulation. Mol Cell 5:299–309CrossRefGoogle Scholar
- Roggi C, Sabbioni E, Minoia C, Ronchi A, Gatti A, Hansen B, Silva S, Maccarini L (1995) Trace element reference values in tissues from inhabitants of the European Union. IX. Harmonization of statistical treatment: blood cadmium in Italian subjects. Sci Total Environ 166:235–243CrossRefGoogle Scholar
- Simmons R, Sukreeyapongse O, Noble A, Chinabut N (2005a) Report of LDD-IWMI land zoning and Cd risk assessment activities undertaken in Phatat Pha Daeng and Mae Tao Mai sub-districts, Mae Sot, Tak Province, Thailand. Final report. Bangkok, Thailand: International Water Management Institute (IWMI), SEA Regional Office; Bangkok, Thailand: Land Development Department. http://cpspace.cgiar.org/handle/10568/39660. Accessed 06 July 2018
- Swaddiwudhipong W, Limpatanachote P, Mahasakpan P, Krintratun S, Padungtod C (2007) Cadmium-exposed population in Mae Sot District, Tak Province: 1. Prevalence of high urinary cadmium levels in the adults. Medical. J Med Assoc Thail 90:143–148Google Scholar
- World Health Organization (2000) Chapter 6.3 cadmium: air quality guidelines-2nd edition. Denmark: WHO regional office for Europe. http://www.euro.who.int/__data/assets/pdf_file/0016/123073/AQG2ndEd_6_3cadmium.pdf. Accessed 06 July 2018