High glucose levels decrease proliferation of cultured human fetal cells from placenta

We used the placenta as a source of undifferentiated cells to study the effect high glucose levels can have on human fetal cell proliferation in vitro. Cells were subcultured in a modified minimum essential medium with 10% fetal bovine serum containing either 5.5 mmol/L (100 mg/dl) d-glucose (control), 11 mmol/L (200 mg/dl) d-glucose, or 22 mmol/L (400 mg/dl) d-glucose. Cells grown in mannitol-containing media were used as controls for osmolality. After 3 and 7 days' growth in different media, the labeling index was determined by autoradiographic analysis, and cell numbers were determined with a Coulter counter. The labeling indices for cells grown 3 days in 11 or 22 mmol/L d-glucose were 89% (p < 0.002) and 84% (p < 0.001), respectively, of control cells grown in 5.5 mmol/L d-glucose. After 7 days' growth, the labeling indices of cells grown in 11 or 22 mmol/L d-glucose were 84% (p < 0.002) and 70% (p < 0.001), respectively, of cells grown in 5.5 mmol/L d-glucose media. There was a significant decrease in the number of cells present at both 3 and 7 days in cultures grown in 22 mmol/L d-glucose compared with control. We conclude that a few day's exposure to high glucose levels can have an effect on proliferation of human placental cells in vitro. We suggest that a glucose effect on proliferation of other cells derived from the products of conception might be one mechanism contributing to abnormal development in some pregnancies of diabetic women.