Objective
To study the effects of insulin and metformin on primary trophoblasts from early pregnancies. Design: Experimental in vitro study. Setting: Academic research institute. Patient(s): Trophoblasts from healthy patients undergoing first trimester elective termination of pregnancy and primary lung fibroblasts (IMR-90). Intervention(s): Culture and treatment with insulin and metformin of primary trophoblasts and primary lung fibroblasts (IMR-90). Main outcome measure(s): DNA damage measured by expression of γ-H2AX with immunofluorescence and Western blot. Apoptosis measured by expression of cleaved caspase-3 by Western blot. Cell survival measured by cell proliferation assay. Result(s): Culture of purified primary trophoblast cells in the presence of insulin at levels as low as 1 nM resulted in a 386% increase in the number of cell with elevated γ-H2AX expression, a 66% reduction in cell survival and a marked increase of cleaved caspase-3 expression. Pretreatment of trophoblasts with therapeutic doses of metformin prevented the detrimental effects of insulin. Treatment with insulin and/or metformin had no effects on primary fibroblasts.