Pravastatin and-L-arginine combination improves umbilical artery blood flow and neonatal outcomes in dichorionic twin pregnancies through an nitric oxide-dependent vasorelaxant effect

Exogenous L-arginine administration improves uterine vascular perfusion, uteroplacental thickness, steroid concentrations, and nitric oxide levels in pregnant buffaloes under subtropical conditions

Heat stress (HS) during pregnancy adversely affects uterine vascular perfusion and fetal development. L-arginine (L-Arg), a nitric oxide (NO) precursor, has been proven to enhance an organ's vascular perfusion. Therefore, this study aimed to examine the effect of L-Arg administration on the pregnant buffaloes' uterine hemodynamics and uteroplacental thickness under environmental HS conditions. For this purpose, pluriparous (n=12) HS-pregnant buffaloes (mid-gestation, 180-190 d; temperature humidity index > 85) were haphazardly assigned into two groups, either administered a single intravenous (IV) bolus of 5 mg/kg BW of L-Arg Hcl (n=6; ARG) or received normal saline (0.9%; IV; 25 ml) that served as a control group (n=6; CON). Combined uteroplacental thickness (CUPT, mm), middle uterine arteries' (MUA) diameter (mm), and uterine Doppler hemodynamics (ipsi-lateral and contralateral to the pregnant horn) were examined utilizing B-mode and color Doppler ultrasonography, respectively. The serum levels of progesterone (P4), estradiol 17 β (E2), nitric oxide (NO), and total antioxidant capacity (TAC) were assayed using commercial kits. The experimental time points were -1, 0, 2, 4, 24, 48, 72, 96, and 120 h post-L-Arg administration. The ARG group showed higher (P < 0.05) CUPT and MUA diameter values starting at 24 h post-treatment and onward than the control buffalo cows. In addition, there were improvements (P<0.05) in the blood flow parameters in the ipsilateral MUA after L-Arg treatment evidenced by lower values of pulsatility and resistive indices starting at 48 and 4 h, respectively and onward, and higher values of peak systolic velocity, colored areas toward the pregnant uterine horn (both 24-72 h). Increases in the NO levels were found during the period between 4 and 120 h in the ARG group compared to the CON group. Moreover, significant increases in the E2 and P4 means were noted in the ARG group, especially at 24 h onward, respectively compared to the CON group. Concerning the TAC status, neither the administration nor the hours affected serum TAC levels in the HS pregnant buffaloes (CON and ARG). In conclusion, L-Arg administration improved uteroplacental thickness and enhanced uterine hemodynamics, NO levels, and steroids production in mid-pregnant buffalo cows under environmental heat stress conditions which could improve fetal growth and development.

Effect of Vitamin D Supplementation on the Cerebral Placental Ratio in Pregnancy Complicated with Early Fetal Growth Restriction

Fetal growth restriction (FGR) is a complication of pregnancy connected with increased risk of intrauterine fetal demise. To increase the diagnostic accuracy, the cerebral placental ratio (CPR) is used. Vitamin D may play a role in the regulation of vascular flow in the fetus. The aim is to assess the relationship between CPR and vitamin D supplementation in fetuses with early FGR. It is a prospective cohort study. Pregnant females were divided into groups with 2000 IU and <500 IU of vitamin D. Both groups were observed for 14 days; USG was performed three times with one-week intervals. EFW and CPR were measured. Absolute CPR values were initially observed to differ significantly (p = 0.0032). Measurements on the seventh day of observation indicated that CPR was significantly higher (p = 0.0455) in fetuses of patients receiving vitamin D at a dose of 2000 IU 1.75 (IQR: 1.47; 2.06) vs. <500 IU group 1.55 (IQR: 1.04; 1.52). Similarly, on day 14: (p < 0.0001)—2.39 (IQR: 1.82; 2.69) vs. 1.21 (IQR: 0.98; 1.52). Supplementation with vitamin D at a dose of 2000 IU may have an influence on the increase in the CPR in fetuses with early FGR.

Evaluating the Effect of Pravastatin in Early-Onset Fetal Growth Restriction: A Nonrandomized and Historically Controlled Pilot Study

OBJECTIVE

This study aimed to analyze the effect of pravastatin on angiogenic factors, feto-maternal Doppler findings and pregnancy outcomes in women with early-onset fetal growth restriction (FGR) treated with pravastatin compared with nontreated controls.

STUDY DESIGN

This was a pilot study conducted between March 2016 and September 2017. Women with single pregnancies and FGR diagnosed at ≤ 28 weeks of gestation were offered 40 mg of pravastatin daily. Doppler progression, soluble fms-like tyrosine kinase 1 (sFlt-1)/placental growth factor (PlGF) values, and pregnancy outcomes were assessed and compared with consecutive historical controls. Controls were matched to treated women for gestational age, maternal characteristics, maternal and obstetric history, Doppler severity classification, and angiogenic factors at diagnosis. The sFlt-1/PlGF was measured in maternal serum at two different times: before pravastatin was started (ratio M0) and during pravastatin treatment (ratio M1). Doppler severity was classified into four categories: normal, mild, moderate, and severe.

RESULTS

A total of 38 women were enrolled in this study. No differences were observed in baseline characteristics between groups. However, when compared with the ratio M0, M1 was increased by a median (interquartile range) of 67.0 (-34.8 to 197.3) in the control group but decreased by a median (interquartile range) of -10.1 (-53.1 to -0.07) in the pravastatin treated group (p < 0.001). No significant differences were observed in Doppler progression throughout pregnancy. Median interval from diagnosis to delivery was extended by 16.5 days, the median newborn birthweight was increased from 1,040 to 1,300 g, and the number of women with preeclampsia decreased from 9 (47.4%) to 6 (31.6%) in treated women; however, these trends were not statistically significant.

CONCLUSION

In women with early-onset FGR, treatment with pravastatin 40 mg daily was associated with significant improvement in the angiogenic profile. Additionally, median pregnancy duration and median birthweight increased and the incidence of PE was reduced in treated women. Nevertheless, since this pilot study was underpowered, none of these differences were statistically significant.

KEY POINTS

· Pravastatin improves sFlt-1/PlGF in FGR.. · Pregnancy duration tended to be greater in treated women.. · Birthweight tended to be greater in treated women..

A systematic review and meta-analysis on the effects of statins on pregnancy outcomes

BACKGROUND AND AIMS

Statins are contraindicated in pregnancy, due to their potential teratogenicity. However, data are still inconsistent and some even suggest a potential benefit of statin use against pregnancy complications. We aimed to investigate the effects of statins on pregnancy outcomes, including stillbirth, fetal abortion, and preterm delivery, through a systematic review of the literature and a meta-analysis of the available clinical studies.

METHODS

A literature search was performed through PubMed, Scopus, and Web of Science up to 16 May 2020. Data were extracted from 18 clinical studies (7 cohort studies, 2 clinical trials, 3 case reports, and 6 case series). Random effect meta-analyses were conducted using the restricted maximum likelihood method. The common effect sizes were calculated as odds ratios (ORs) and their 95% confidence interval (CI) for each main outcome.

RESULTS

Finally, nine studies were included in the meta-analysis. There was no significant association between statin therapy and stillbirth [OR (95% CI) = 1.30 (0.56, 3.02), p=0.54; I² = 0%]. While statin exposure was significantly associated with increased rates of spontaneous abortion [OR (95% CI) = 1.36 (1.10-1.68), p=0.004, I² = 0%], it was non-significantly associated with increased rates of induced abortion [OR (95% CI) = 2.08 (0.81, 5.36), p=0.129, I² = 17.33%] and elective abortion [OR (95% CI) = 1.37 (0.68, 2.76), p=0.378, I² = 62.46%]. A non-significant numerically reduced rate of preterm delivery was observed in statin users [OR (95% CI) = 0.47 (0.06, 3.70), p=0.47, I² = 76.35%].

CONCLUSIONS

Statin therapy seems to be safe as it was not associated with stillbirth or induced and elective abortion rates. Significant increase after statin therapy was, however, observed for spontaneous abortion. These results need to be confirmed and validated in future studies.

Pravastatin plus L-arginine prevents adverse pregnancy outcomes in women with uteroplacental vascular dysfunction

BACKGROUND

Uteroplacental vascular dysfunction, characterized by diminished uterine artery (UtA) blood flow in the second trimester is a clinically useful predictor of the further development of preeclampsia, fetal growth restriction and stillbirth. Efforts to develop effective treatments to protect pregnancies with abnormal UtA Dopplers would be of significant clinical benefit for mothers and their fetuses.

OBJECTIVE

The aim of this pilot non randomized control study was to use pravastatin +L-arginine to improve uteroplacental haemodynamics and prevent adverse maternal and neonatal outcomes in women with abnormal Dopplers and high risk for developing adverse pregnancy outcomes.

STUDY DESIGN

This study was performed between 2015 and 2018. All women received primary care at OB/GYN Polyclinic Jurisic and Narodni Front University Hospital, University of Belgrade Medical School, Serbia. Approval for investigational drug use was obtained and all women gave informed consent. 10 pregnant women with a poor obstetric history that developed uteroplacental dysfunction (UtA pulsatility index (PI) above the 95th percentile and notching) at 20.5 weeks IQR [17.7-22] gave consent to be treated daily with pravastatin (40 mg) and L-arginine (1.5 g) to improve placental blood flow and pregnancy outcomes. 5 women remained untreated after diagnosis at 21 weeks [20-22] (control group). Due to presence of risk factors for pregnancy complications, close maternal and fetal monitoring was undertaken in all patients. Doppler examinations were performed to monitor changes in placental vascular resistance and fetal well-being and growth.

RESULTS

PRAV+L-arginine improved uteroplacental haemodynamics, increased fetal growth and prevented early onset preeclampsia leading to delivery close to term (delivery date: median 38 weeks, IQR[36.5-39]) and appropriate weight for gestational age compared to controls, in which placental blood flow did not improve and 2 women developed severe early onset preeclampsia. Neonates from the control group were born preterm (25 weeks IQR[23.5-25]), growth restricted and spent several months at NICU. Two neonates died due to prematurity-associated complications. PRAV+L-arginine treatment prolonged pregnancies for 4.1 months, compared to 26 days in the untreated group, preventing neonatal complications associated with prematurity. The infants are now 1-3 years old and show normal growth and development.

CONCLUSION

This study describes the successful management with pravastatin+L-arginine of 10 pregnant patients with uteroplacental vascular dysfunction and high risk of adverse maternal and fetal outcomes. A larger study is being organized to confirm these observations.

Placental nitric oxide formation and endothelium-dependent vasodilation underlie pravastatin effects against angiogenic imbalance, hypertension in pregnancy and intrauterine growth restriction

Pre-eclampsia and hypertensive disorders of pregnancy are frequently associated with foeto-placental growth restriction, and that may be triggered by angiogenic imbalance and endothelial dysfunction. Impaired nitric oxide (NO) bioavailability seems to be involved in these pathophysiological changes observed in hypertensive pregnancy. Pravastatin has shown efficacy and to be safe during hypertension in pregnancy. However, NO involvement in pravastatin effects during maternal hypertension and foeto-placental development is unclear. Therefore, we aimed to examine pravastatin effects on placental NO formation, endothelium-dependent vasodilation, systolic blood pressure and foeto-placental development in hypertensive pregnant rats. Biochemical determinants of angiogenesis and oxidative stress were also assessed. Pregnant rats were distributed into four groups: normal pregnancy (Norm-Preg), pregnancy+pravastatin (Preg-Prava), hypertensive pregnancy (HTN-Preg) and hypertensive pregnancy+pravastatin (HTN-Preg+Prava). Our results showed that pravastatin treatment blunts hypertension and foeto-placental growth restriction. Also, increases in placental NO levels were found in the HTN-Preg+Prava group. Pravastatin prevents impaired endothelium-dependent acetylcholine-induced vasodilation, exacerbated contractile response to phenylephrine and increases in oxidative stress in the HTN-Preg+Prava group. Increased soluble fms-like tyrosine kinase-1-to-placental growth factor (sFlt-1/PlGF) ratio is reversed by pravastatin treatment in the HTN-Preg+Prava group. We conclude that NO formation and endothelium-dependent vasodilation underlie pleiotropic effects associated with pravastatin treatment against hypertension in pregnancy, intrauterine growth restriction, vascular dysfunction and angiogenic imbalance.

Nitric oxide and the biology of pregnancy

Nitric oxide (NO) is a key regulator of both maternal and fetal homeostasis during pregnancy, facilitating the maternal cardio-vascular changes, fetal development and growth and adaptation to extrauterine life. Dysfunction of the NO system during pregnancy is associated to placental and vascular-related diseases such as hypertensive disorders of pregnancy (HDP) and intrauterine growth restriction (IUGR). Emerging therapeutic strategies involving NO precursors, NO donors, natural derivatives or pharmacological modulators of the NO system seem hold promise for the treatment of such conditions of pregnancy.