Fangxian Lu

Using Pravastatin to Improve the Vascular Reactivity in a Mouse Model of Soluble Fms-Like Tyrosine Kinase-1―Induced Preeclampsia

OBJECTIVE: To estimate the effects of pravastatin on the altered vascular function in a mouse model of preeclampsia induced by overexpression of soluble fms-like tyrosine kinase-1 (sFlt-1). METHODS: Pregnant CD1 mice, at day 8 of gestation, were randomly allocated to injection using the tail vein of the adenovirus carrying sFlt-1 (109 plaque-forming units in 100 microliters; sFlt-1 group) or mFc (109 plaque-forming units) as virus control, and then to receive pravastatin (Pra; 5 mg/kg/d) dissolved in drinking water or control. The mice in four groups (sFlt-1, sFlt-1-pravastatin, mFc, and mFc-pravastatin; n=4–6 per group) were killed at day 18 of gestation and 2-mm segments of carotid artery were used for vascular reactivity studies. Serum sFlt-1 levels were also measured by enzyme-linked immunosorbent assay. RESULTS: Mice in the sFlt-1 group had the highest responses to phenylephrine. Treatment with pravastatin decreased the contractile responses to phenylephrine (maximal effect [mean±standard error of the mean] 137.35± 27.70 compared with 42.24±8.76; P=.006) for sFlt-1 compared with sFlt-1-pravastatin, respectively. There were no differences in the contractile responses to thromboxane A2. The vasorelaxant responses to acetylcholine were significantly highest in the mFc-pravastatin group, with a maximal effect of 108.37±5.25 compared with 89.77±3.96 in the mFc group (P=.008), and those with sodium nitroprusside were not different across the four groups. Serum sFlt-1 levels were not different at baseline (day 8) but were significantly lower in sFlt-1-pravastatin compared with sFlt-1 at day 18 (59.42±5.31 compared with 102.59±15.15 ng/mL; P=.01). CONCLUSION: Pravastatin improved the vascular reactivity in this murine model of preeclampsia by decreasing sFlt-1 levels. Statins should be evaluated for the prevention of the vascular abnormalities of preeclampsia.

Long-term maternal cardiovascular function in a mouse model of sFlt-1-induced preeclampsia

Our aim was to evaluate the long-term effects of preeclampsia on vascular function in a mouse model induced by sFlt-1 overexpression. CD-1 mice at day 8 of gestation were injected via the tail vein with adenovirus carrying sFlt1 (AdsFlt1), adenovirus carrying the murine IgG2alpha Fc fragment as the adenovirus control (AdmFc), or saline. Vascular function in the mothers was investigated 6-8 mo after delivery by recording blood pressure (BP) by telemetry (AdsFlt1 n = 8, AdmFc n = 6, saline n = 4) and exploring carotid artery reactivity in a wire myograph (AdsFlt1 n = 6, AdmFc n = 8, saline n = 4). sFlt-1 blood levels at 6-8 mo postpartum had returned to low levels and were comparable between the three groups (P = 0.808). There was no statistically significant difference in BP (P = 0.067) or vascular reactivity between the three groups of postpartum mice (phenylephrine P = 0.079, thromboxane P = 0.979, serotonin P = 0.659, acetylcholine P = 0.795, sodium nitroprusside P = 0.728, isoproterenol P = 0.370). Our results indicate that in a mouse model overexpression of sFlt-1 does not lead to increased in BP and altered vascular function in the absence of the pregnancy and has no long-term effect on BP and vascular function in the postpartum mothers. Our findings favor the hypothesis that increased cardiovascular diseases in women with history of preeclampsia are likely the result of preexisting risk factors common to preeclampsia and cardiovascular diseases.

Endothelial growth factor therapy improves preeclampsia-like manifestations in a murine model induced by overexpression of sVEGFR-1

This study examines the effects of VEGF-121 therapy in an animal model of preeclampsia induced by overexpression of soluble VEGF receptor 1 (sVEGFR-1). At day 8 of gestation, CD-1 mice were implanted with subcutaneous osmotic pumps containing either VEGF-121 or vehicle and fitted with telemetric blood pressure (BP) catheters for continuous BP monitoring (days 8-18 of gestation). On day 9, the animals in the VEGF-121 group were randomly allocated for injection with adenovirus carrying sVEGFR-1 or the murine immunoglobulin G2α Fc fragment (mFc) as virus control (Adv-sVEGFR-1; Adv-mFc). Animals in the vehicle group were injected with Adv-sVEGFR-1. On day 18, mice were euthanized, placentas and pups weighted, carotid arteries isolated, and their responses studied in vitro using a wire myograph for isometric tension recording. In mice overexpressing sVEGFR-1, treatment with VEGF-121 significantly reduced BP from days 10 to 18 of gestation compared with that of vehicle. VEGF-sVEGFR-1 animals had significantly higher vasorelaxant response to sodium nitroprusside and significantly lower contractile response to the thromboxane agonist (U-46619) compared with that of the vehicle-sVEGFR-1 mice. Phenylephrine and acetylcholine responses did not significantly vary between the VEGF-sVEGFR-1 and the vehicle-sVEGFR-1 mice. Average pup weight was significantly lower in the vehicle-sVEGFR-1 group compared with the VEGF-sVEGFR-1 and VEGF-mFc groups. In conclusion, VEGF-121 therapy attenuates vascular dysfunction and diminishes intrauterine growth abnormality in an animal model of preeclampsia induced by overexpression of sVEGFR-1. Modulation of VEGF pathway turns into a promising therapeutic approach of preeclampsia.

The effect of prepregnancy obesity and sFlt-1–induced preeclampsia-like syndrome on fetal programming of adult vascular function in a mouse model

OBJECTIVE The purpose of this study was to test the hypothesis that prepregnancy obesity and soluble fms-like tyrosine kinase-1 (sFlt-1)-induced preeclampsia lead to altered vascular function in the offspring later in life. STUDY DESIGN CD-1 female mice were placed on a low-fat (LF) or high-fat (HF) diet before mating. On day 8 of pregnancy, the HF mice were injected with adenovirus that carried either sFlt-1 (HF sFlt-1) or murine immunoglobulin G2alpha Fc fragment (HF mFc). LF dams received saline solution. After being weaned, all offspring were placed on a standard diet. At 3 months of age, the carotid artery was isolated for in vitro vascular reactivity studies. RESULTS Among male offspring, the response to phenylephrine was significantly lower in the HF sFlt-1 group. The response to serotonin in males and to thromboxane in females was lower in the HF sFlt-1 and HF mFc groups. In females, the HF sFlt-1 and LF groups displayed less relaxation to acetylcholine. The response to phenylephrine was significantly lower in females than males in the HF mFc and LF groups. The response to thromboxane was significantly lower in the HF sFlt-1 females, compared with males. CONCLUSION Prepregnancy obesity and preeclampsia alter fetal programming of adult vascular function. The mechanism is complex and gender specific.