Nicotinamide benefits both mothers and pups in two contrasting mouse models of preeclampsia

Preeclampsia (PE), high blood pressure and protein in the urine in the last third of pregnancy, complicates about 1 in 20 human pregnancies, and it is one of the leading causes of pregnancy-related maternal deaths. The only definitive treatment, induced delivery, invariably results in premature babies. Blood pressure-lowering drugs help, but results in preventing preterm delivery and correcting the fetal growth restriction (FGR) that also occurs in PE have been disappointing. Here we show that feeding high doses of nicotinamide, a vitamin, improves the maternal condition, prolongs pregnancies, and prevents FGR in mice having PE-like conditions due to two contrasting causes. Because nicotinamide benefits both mothers and pups, it merits evaluation for preventing or treating PE in humans

Relationship Between Short Term Variability (STV) and Onset of Cerebral Hemorrhage at Ischemia-Reperfusion Load in Fetal Growth Restricted (FGR) Mice.

Fetal growth restriction (FGR) is a risk factor exacerbating a poor neurological prognosis at birth. A disease exacerbating a poor neurological prognosis is cerebral palsy. One of the cause of this disease is cerebral hemorrhage including intraventricular hemorrhage. It is believed to be caused by an inability to autoregulate cerebral blood flow as well as immaturity of cerebral vessels. Therefore, if we can evaluate the function of autonomic nerve, cerebral hemorrhage risk can be predicted beforehand and appropriate delivery management may be possible. Here dysfunction of autonomic nerve in mouse FGR fetuses was evaluated and the relationship with cerebral hemorrhage incidence when applying hypoxic load to resemble the brain condition at the time of delivery was examined. Furthermore, FGR incidence on cerebral nerve development and differentiation was examined at the gene expression level. FGR model fetuses were prepared by ligating uterine arteries to reduce placental blood flow. To compare autonomic nerve function in FGR mice with that in control mice, fetal short term variability (STV) was measured from electrocardiograms. In the FGR group, a significant decrease in the STV was observed and dysfunction of cardiac autonomic control was confirmed. Among genes related to nerve development and differentiation, Ntrk and Neuregulin 1, which are necessary for neural differentiation and plasticity, were expressed at reduced levels in FGR fetuses. Under normal conditions, Neurogenin 1 and Neurogenin 2 are expressed mid-embryogenesis and are related to neural differentiation, but they are not expressed during late embryonic development. The expression of these two genes increased in FGR fetuses, suggesting that neural differentiation is delayed with FGR. Uterine and ovarian arteries were clipped and periodically opened to give a hypoxic load mimicking the time of labor, and the bleeding rate significantly increased in the FGR group. This suggests that FGR deteriorates cardiac autonomic control, which becomes a risk factor for cerebral hemorrhage onset at birth. This study demonstrated that cerebral hemorrhage risk may be evaluated before parturition for FGR management by evaluating the STV. Further, this study suggests that choosing an appropriate delivery timing and delivery method contributes to neurological prognosis improvement

Hepatic dysfunction and thrombocytopenia induced by excess sFlt1 in mice lacking endothelial nitric oxide synthase

Liver dysfunction is a major problem in patients with severe preeclampsia (PE), hemolysis, elevated liver enzymes, and low platelet count (HELLP) syndrome, or in patients receiving anti-vascular endothelial growth factor (VEGF) therapy. Excessive soluble fms-like tyrosine kinase 1 (sFlt1) that antagonizes VEGF has been implicated in the pathogenesis of PE. VEGF increases the expression of endothelial nitric oxide synthase (eNOS) and activates it. eNOS polymorphisms that cause reduced NO production are associated with PE. The aim of this study was to clarify the role on hepatic function by excess sFlt1 in the absence of eNOS gene product. We first overexpressed sFlt1 using adenovirus in eNOS −/− and eNOS +/+ mice. Excessive sFlt1 and lack of eNOS synergistically increased plasma levels of liver transaminases, exacerbated infiltration of inflammatory cells, elevated expression levels of cytokines in the liver, and aggravated oxidative stress and coagulation abnormalities. Lack of eNOS in the presence of excess sFlt1 also induced thrombocytopenia, whereas eNOS +/+ mice with excess sFlt1 alone showed no or modest liver phenotype. Taken together, excessive sFlt1 and lack of eNOS synergistically induce hepatic dysfunction and thrombocytopenia, suggesting a novel role for VEGF and nitric oxide signaling in hepatocyte-endothelial cross-talk in health and in liver injury states

Data_Sheet_1_Relationship Between Short Term Variability (STV) and Onset of Cerebral Hemorrhage at Ischemia–Reperfusion Load in Fetal Growth Restricted (FGR) Mice.docx

<p>Fetal growth restriction (FGR) is a risk factor exacerbating a poor neurological prognosis at birth. A disease exacerbating a poor neurological prognosis is cerebral palsy. One of the cause of this disease is cerebral hemorrhage including intraventricular hemorrhage. It is believed to be caused by an inability to autoregulate cerebral blood flow as well as immaturity of cerebral vessels. Therefore, if we can evaluate the function of autonomic nerve, cerebral hemorrhage risk can be predicted beforehand and appropriate delivery management may be possible. Here dysfunction of autonomic nerve in mouse FGR fetuses was evaluated and the relationship with cerebral hemorrhage incidence when applying hypoxic load to resemble the brain condition at the time of delivery was examined. Furthermore, FGR incidence on cerebral nerve development and differentiation was examined at the gene expression level. FGR model fetuses were prepared by ligating uterine arteries to reduce placental blood flow. To compare autonomic nerve function in FGR mice with that in control mice, fetal short term variability (STV) was measured from electrocardiograms. In the FGR group, a significant decrease in the STV was observed and dysfunction of cardiac autonomic control was confirmed. Among genes related to nerve development and differentiation, Ntrk and Neuregulin 1, which are necessary for neural differentiation and plasticity, were expressed at reduced levels in FGR fetuses. Under normal conditions, Neurogenin 1 and Neurogenin 2 are expressed mid-embryogenesis and are related to neural differentiation, but they are not expressed during late embryonic development. The expression of these two genes increased in FGR fetuses, suggesting that neural differentiation is delayed with FGR. Uterine and ovarian arteries were clipped and periodically opened to give a hypoxic load mimicking the time of labor, and the bleeding rate significantly increased in the FGR group. This suggests that FGR deteriorates cardiac autonomic control, which becomes a risk factor for cerebral hemorrhage onset at birth. This study demonstrated that cerebral hemorrhage risk may be evaluated before parturition for FGR management by evaluating the STV. Further, this study suggests that choosing an appropriate delivery timing and delivery method contributes to neurological prognosis improvement.</p

Reduced Uterine Perfusion Pressure (RUPP) Model of Preeclampsia in Mice

<div><p>Preeclampsia (PE) is a pregnancy-induced hypertension with proteinuria that typically develops after 20 weeks of gestation. A reduction in uterine blood flow causes placental ischemia and placental release of anti-angiogenic factors such as sFlt-1 followed by PE. Although the reduced uterine perfusion pressure (RUPP) model is widely used in rats, investigating the role of genes on PE using genetically engineered animals has been problematic because it has been difficult to make a useful RUPP model in mice. To establish a RUPP model of PE in mice, we bilaterally ligated ovarian vessels distal to ovarian branches, uterine vessels, or both in ICR-strain mice at 14.5 days post coitum (dpc). Consequently, these mice had elevated BP, increased urinary albumin excretion, severe endotheliosis, and mesangial expansion. They also had an increased incidence of miscarriage and premature delivery. Embryonic weight at 18.5 dpc was significantly lower than that in sham mice. The closer to the ligation site the embryos were, the higher the resorption rate and the lower the embryonic weight. The phenotype was more severe in the order of ligation at the ovarian vessels < uterine vessels < both. Unlike the RUPP models described in the literature, this model did not constrict the abdominal aorta, which allowed BP to be measured with a tail cuff. This novel RUPP model in mice should be useful for investigating the pathogenesis of PE in genetically engineered mice and for evaluating new therapies for PE.</p></div

Ligation of uterine vessels reduces arterial blood flow of uterine arcades.

<p>Doppler blood velocity waveforms were obtained from an artery of the uterine arcade before (<b>A</b>) or after (<b>B</b>) ligation of ovarian vessels. (<b>C</b>) Summary of arterial blood flow velocity of 4 uterine arcades (4 peaks each) before and after ligation of ovarian vessels. Doppler blood velocity waveforms were obtained from an artery of the uterine arcade before (<b>D</b>) or after (<b>E</b>) ligation of uterine vessels. (<b>F</b>) Summary of arterial blood flow velocity of 5 uterine arcades (4 peaks each) before and after ligation of uterine vessels. (<b>G</b>) Percentage of velocity change relative to velocity before ligation. n = 4 (ovarian vessels) and n = 5 (uterine vessels).</p

Hypoxia by RUPP increases placental sFlt-1 expression.

<p>mRNA expression of HIF-1α (<b>A</b>), sFlt-1 (<b>B</b>), VEGF (<b>D</b>), and PlGF (<b>F</b>) in placentae at 18.5 dpc. Plasma concentrations of sFlt-1 (<b>C</b>) and VEGF (<b>E</b>) at 18.5 dpc dams.</p

RUPP surgery causes miscarriages and embryonic growth restriction.

<p>(<b>A</b>) Continuing pregnancies with or without the ligation at 14.5 dpc; parentheses show number of pregnancies at 14.5 dpc. (<b>B</b>) Embryo survival from 14.5 dpc to 18.5 dpc. (<b>C</b>) Representative images of embryos. Bars, 1 cm. (<b>D</b>) Embryonic weight at 18.5 dpc; parentheses show number of embryos/number of dams. (<b>E</b>) Placental weight at 18.5 dpc. (<b>F</b>) Embryonic weight/placental weight ratios. (<b>G</b>) Relationship between resorption rate and embryonic position in the uterus. (<b>H</b>) Relationship between embryonic weight and position in the uterus. Embryonic position was numbered from the position of ligation.</p