Blood metal levels and third trimester maternal plasma matrix metalloproteinases (MMPs) (Lay summary)

Au F, Bielecki A, Blais E, Fisher M, Cakmak S, Basak A, Gomes J, Arbuckle TE, Fraser WD, Vincent R, Kumarathasan P. Chemosphere. 2016 Sep;159:506-15. doi: 10.1016/j.chemosphere.2016.06.011.

Women and the developing fetus can be exposed to a variety of metals (i.e. lead, cadmium, manganese, mercury and arsenic) that may be associated with adverse health and birth outcomes. It is therefore important to understand how metals may affect the pregnancy and infant health. To do this, data from the MIREC Study were used to investigate the association between metal levels in maternal blood and a class of biological molecules known as matrix metalloproteinases in the blood of these mothers in their third trimester. These molecules are known to play an important role in pregnancy. In this analysis, data were available for 1,533 women recruited from 10 cities across Canada between 2008 and 2011. Maternal blood samples were collected during the first and third trimesters and were analyzed for lead, cadmium, manganese, mercury and arsenic levels. A series of biological molecules were measured in third trimester blood samples. Information on the health of the women (e.g., high blood pressure, diabetes, smoking history, age, and weight) was collected from questionnaires and clinical examinations during pregnancy.

The results suggested that changes in maternal blood metal levels appeared to affect the levels of matrix metalloproteinases in the mothers’ blood. Also, maternal blood matrix metalloproteinases were affected differently by different metals. These findings will help focus future research that hopefully will lead to a better understanding of what these changes in levels of the biological molecules mean in terms of affecting the health of the pregnancy or infant.