LISBON — Neutrophil infiltration and vascular inflammation were substantially more prevalent and severe in blood vessels from overweight and obese women than in vessels taken from normal-weight women in a study of 22 women.
“The data indicate that the vasculature of obese women is inflamed and susceptible to developing hypertension,” Scott W. Walsh, Ph.D., said at the 15th World Congress of the International Society for the Study of Hypertension in Pregnancy.
“We speculate that neutrophil infiltration and vascular inflammation puts obese women at risk for preeclampsia” through the release of reactive oxygen species and immunostimulants. This may explain why obesity is a risk factor for preeclampsia.
Until now, the pathophysiologic link between obesity and preeclampsia has been unclear, said Dr. Walsh, a professor of ob.gyn. at Virginia Commonwealth University in Richmond.
Dr. Walsh and his associates assessed neutrophil infiltration and vascular inflammation in the blood vessels of adipose tissue biopsies taken from volunteers. Participating women were divided into three groups based on their body mass index. Five normal-weight women had a BMI of less than 25 kg/m
Neutrophil infiltration was measured using a monoclonal-antibody stain against CD66b, a granulocyte membrane antigen (about 96% of granulocytes in blood vessels are neutrophils). Inflammation was measured with monoclonal-antibody stains against two markers of inflammation, nuclear factor (NF)-κB and cyclooxygenase (COX)-2. The extent of vessel staining with these reagents was gauged in fixed, adipose tissue specimens by two measures: a visual score scale of 0–3 and stained vessels as a percent of all vessels examined.
By both measurements, all three stains were significantly increased in both overweight and obese women, compared with the normal-weight controls. The greatest staining was in the vessels from obese women.
For example, for NF-κB staining, the visual score was about 0.3 in biopsies from normal-weight women, about 1.1 in overweight women, and about 2.6 in obese women. The percent of vessels stained was about 28%, 60%, and 90%, respectively. Similar results were obtained with the stains for neutrophils and for COX-2.
The patterns seen in adipose tissue are likely to be representative of the entire vasculature in each woman. In fact, inflammation may be even more extensive in certain other vascular beds in each woman, Dr. Walsh said.
The images show blood vessels in fixed, adipose-tissue biopsies that were stained for the cytokine NF-κB, a marker for vascular inflammation. The control specimen (left) is from a normal-weight woman and shows no NF-κB staining. The specimen on the right, from a woman with a BMI of at least 30 kg/m