Abstract 206: Hyperleptinemia Increases Blood Pressure and Decreases Pup Weight in Pregnant Rats
While the relationship of obesity to cardiovascular disease is well recognized, it also has important implications for pregnancy outcomes. Indeed, there is compelling evidence that obesity increases the risk of preeclampsia (PE). The risk of severe and mild PE and PE occurring in early and late gestation are greater in obese and overweight women. Despite the fact that obesity is the leading attributable risk for PE in developed countries, the pathophysiological mechanisms whereby obesity and metabolic factors such as leptin increases the risk for developing PE are unclear. Hyperleptinemia over the levels seen in normal pregnancy has been associated with preeclampsia. Thus the aim of this study was to investigate whether chronic hyperleptinemia causes changes in cardiovascular, metabolic and reproductive systems of pregnant rats. On gestational day (GD) 14, Sprague Dawley rats were assigned to normal pregnant (NP, n=8) group or to NP plus Leptin group (NP+Lep, n=8), in which miniosmotic pump with leptin (0.5 μg/kg/min) was placed intraperitoneally. On GD 19, mean arterial pressure (MAP) was recorded, rats were sacrificed, and blood, placentas and pups were collected. Body weight (BW) and food intake (FI) were measured on GD 16-18. Serum leptin concentration was elevated in NP+Lep compared with NP (0.82 ± 0.05 vs 17.98 ± 2.75 ng/mL, P<0.05). Circulating insulin and glucose levels were similar in NP and NP+Lep groups (both P>0.05). MAP was higher in NP+Lep compared with NP (102.40 ± 2.38 vs 121.30 ± 8.13 mmHg, P<0.05). BW was decreased in NP+Lep compared with NP at GD 19 (330.90 ± 9.08 vs 284.10 ± 8.58 g, P<0.05), probably due to the reduced FI of the NP+Ins group compared with NP during GD 16-18 (23.45 ± 0.61 vs 8.61 ± 0.83 g/day, P<0.05). Although the number of viable fetuses per rat was similar between groups (P>0.05), fetuses and placentas of the NP+Lep group were lighter than those of the NP group (2.29 ± 0.06 vs 2.11 ± 0.06 g and 0.58 ± 0.01 vs 0.50 ± 0.02 g, respectively, both P<0.05). In conclusion, leptin increases blood pressure, despite its effect of reducing body weight during pregnancy, representing a possible mechanism to induce hypertension in preeclampsia. In addition, leptin decreases pup and placental weights, which could lead to abnormal fetal outcomes.
- © 2012 by American Heart Association, Inc.