Neutrophil Release of Myeloperoxidase in Systemic Vasculature of Obese Women May Put Them at Risk for Preeclampsia

Obesity is a risk factor for preeclampsia, but the reason for this risk is unknown. Neutrophils infiltrate into systemic blood vessels of both obese and preeclamptic women. Neutrophils are a major source of myeloperoxidase (MPO), which is associated with hypertension. We tested the hypothesis that systemic vasculature of both obese and preeclamptic women will have a significant presence of MPO as a result of neutrophil infiltration. We found that immunohistochemical staining of MPO was significantly greater in subcutaneous fat blood vessels of obese women than overweight women, which was significantly greater than normal weight women. Expression of MPO was significantly greater in maternal blood vessels of preeclamptic women than normal pregnant or normal nonpregnant women. In general, when vessels of overweight or normal pregnant women were stained it was primarily for leukocytes in the lumen and not infiltrated into the vessel. In contrast, in obese and preeclamptic women staining was present for leukocytes in the lumen, flattened, and adhered to the endothelium and infiltrated into the vessel wall. There was also extensive diffuse staining for MPO in vessels of obese and preeclamptic women. In conclusion, both obese and preeclamptic women have increased presence of MPO in systemic vasculature as a result of neutrophil infiltration. We speculate that obese women may be at risk of preeclampsia because their vasculature is already prone to hypertension.