Nina Kittelsen Harsem

Dysregulation of the Circulating and Tissue-Based Renin-Angiotensin System in Preeclampsia

The renin–angiotensin system (RAS) participates in preeclampsia; however, the relative contributions from the circulating RAS and the tissue-based, uteroplacental RAS are unknown. We hypothesized that the tissue-based uteroplacental RAS is dysregulated in preeclampsia. We performed microarray and gene expression studies and confirmed the findings on the protein level by immunohistochemistry in ureteroplacental units from 10 preeclamptic women and 10 women with uneventful pregnancies. All of the women were delivered by cesarean section. We also analyzed plasma renin activity and circulating agonistic angiotensin II type 1 (AT1) receptor autoantibodies. In preeclampsia, we found that the angiotensin II AT1 receptor gene was 5-fold upregulated in decidua (maternal origin). We also found AT1 autoantibodies in preeclamptic women and in their offspring by neonatal cardiomyocyte bioassay compared with women with normal pregnancies and their infants (mother: 17.5±2.2 versus 0.05±0.4; fetus: 14.5±1.8 versus 0.5±0.5 &Dgr;bpm). Gene expressions for renin (35.0-fold), angiotensin-converting enzyme (2.9-fold), and angiotensinogen (8.9-fold) were higher in decidua than placenta (fetal origin) in both control and preeclamptic women, whereas the AT1 receptor was expressed 10-fold higher in placenta than in decidua in both groups. Our findings elucidate the ureteroplacental unit RAS in preeclamptic and normal pregnancies. We found that, in preeclampsia, the AT1 receptor expression is particularly high in decidua, combined with pregnancy-specific tissue RAS involving decidual angiotensin II production and AT1 autoantibodies. We also showed that AT1 autoantibodies cross the ureteroplacental barrier. These components could participate in the pathophysiology of preeclampsia.

Adiponectin is reduced in gestational diabetes mellitus in normal weight women

Background.  Adiponectin is an adipose tissue‐derived protein counteracting insulin resistance and inflammation. We have compared women with gestational diabetes mellitus (GDM; n = 22) and normal pregnancies (controls; n = 29) to evaluate whether adiponectin represents a link between endocrine function of adipose tissue and the development of diabetes during pregnancy.

Oxidative Stress and Antioxidant Status in Fetal Circulation in Preeclampsia

Preeclampsia is associated with oxidative stress in maternal circulation. The purpose of this study was to explore oxidative stress and antioxidants in the fetal circulation in preeclampsia. Women with preeclampsia (n = 19) or uncomplicated pregnancies (n = 33) delivered by cesarean section were included. Blood was sampled separately from the umbilical vein and artery. 8-Iso-prostaglandin F2α (8-isoprostane), a stable product of lipid peroxidation, is a reliable marker of oxidative stress. Concentration of total 8-isoprostane in cord plasma was analyzed by gas chromatography–mass spectrometry. Antioxidant status was evaluated measuring ferric reducing ability of plasma and vitamin E. There was no difference between preeclampsia and control groups regarding median plasma concentration of 8-isoprostane in umbilical vein (955 versus 780 pg/mL, p = 0.41) or in umbilical artery (233 versus 276 pg/mL, p = 0.65). Concentration of 8-isoprostane was much higher in plasma from the umbilical vein than artery, suggesting placenta as the source of 8-isoprostane. Median ferric reducing ability of plasma concentration was higher in preeclampsia than in controls, both in the umbilical vein and artery. Median vitamin E concentration in the umbilical vein was higher in preeclampsia, but no difference was found in the umbilical artery. In conclusion, no evidence of increased oxidative stress, evaluated by 8-isoprostane concentration, was found in fetal circulation in preeclampsia.

Regulation of ADRP expression by long-chain polyunsaturated fatty acids in BeWo cells, a human placental choriocarcinoma cell line

Transplacental transfer of maternal fatty acids is critical for fetal growth and development. In the placenta, a preferential uptake of fatty acids toward long-chain polyunsaturated fatty acids (LCPUFAs) has been demonstrated. Adipose differentiation-related protein (ADRP) is a lipid droplet-associated protein that has been ascribed a role in cellular fatty acid uptake and storage. However, its role in placenta is not known. We demonstrate that ADRP mRNA and protein are regulated by fatty acids in a human placental choriocarcinoma cell line (BeWo) and in primary human trophoblasts. LCPUFAs of the n-3 and n-6 series [arachidonic acid (20:4n-6), docosahexaenoic acid (22:6n-3), and eicosapentaenoic acid (20:5n-3)] were more efficient than shorter fatty acids at stimulating ADRP mRNA expression. The fatty acid-mediated increase in ADRP mRNA expression was not related to the differentiation state of the cells. Synthetic peroxisome proliferator-activated receptor and retinoic X receptor agonists increased ADRP mRNA level but had no effect on ADRP protein level in undifferentiated BeWo cells. Furthermore, we show that incubation of BeWo cells with LCPUFAs, but not synthetic agonists, increased the cellular content of radiolabeled oleic acid, coinciding with the increase in ADRP mRNA and protein level. These studies provide new information on the regulation of ADRP in placental trophoblasts and suggest that LCPUFA-dependent regulation of ADRP could be involved in the metabolism of lipids in the placenta.

Homocysteine, Cysteine, and Related Metabolites in Maternal and Fetal Plasma in Preeclampsia

Homocysteine is associated with endothelial dysfunction and cardiovascular disease, and elevated concentrations of homocysteine have been found in preeclampsia. The purpose of this study was to investigate maternal and fetal concentrations of total homocysteine and related metabolites (including cysteine, choline, and betaine), and possible associations with infant birth weight. Women with preeclampsia (n = 47) and controls (n = 51), who underwent cesarean section, were included. Maternal plasma, umbilical vein, and artery plasma were analyzed. Median concentrations of homocysteine, cysteine, choline, and betaine were significantly higher in women with preeclampsia than controls, both in maternal and fetal plasma. There were no differences in folate and vitamin B12 concentrations between the groups, neither for maternal nor fetal samples. Maternal homocysteine concentration was a negative predictor for birth weight only in the preeclampsia group. Elevated homocysteine and cysteine concentration in maternal circulation in preeclampsia is reflected in the fetal circulation. The clinical significance of elevated homocysteine and cysteine concentrations in maternal and fetal compartments in preeclampsia remain to be explored, both regarding fetal growth and development of disease later in life.

Asymmetric Dimethylarginine in the Maternal and Fetal Circulation in Preeclampsia

Preeclampsia is a leading cause of intrauterine growth restriction and preterm birth. Endothelial dysfunction is the common final pathway leading to clinical signs of preeclampsia including hypertension and proteinuria. Asymmetric dimethylarginine (ADMA) is an endogenous inhibitor of NOS and induces endothelial dysfunction by reversibly inhibiting NO production from l-arginine. The purpose of this study was to investigate maternal and fetal concentrations of ADMA, l-arginine, and symmetric dimethylarginine (SDMA). Women with preeclampsia (n = 47) and controls (n = 51) who gave birth by cesarean section were included in the study. We analyzed the maternal plasma and umbilical vein and artery plasma. We found that not only maternal concentrations of ADMA and SDMA but also l-arginine were significantly higher in women with preeclampsia than in controls. In fetal samples, only SDMA concentrations were higher in the preeclampsia group than in controls. The median ADMA concentration was three times higher in the fetal circulation than in the maternal circulation, but there was no difference between the preeclampsia group and the control group, and the veno-arterious gradient indicated that the placenta was the source of ADMA.

The decidual suction method: a new way of collecting decidual tissue for functional and morphological studies

Background.  Studies of extravillous trophoblasts and placental bed spiral arteries are essential for a better understanding of pathological pregnancies such as preeclampsia, intrauterine growth restriction and diabetes mellitus. A major challenge is to obtain representative and sufficient tissue for morphological and functional investigations. Currently, tissue material is mostly harvested by placental bed biopsy (PBB). We describe a new suction method to obtain a larger volume of decidual tissue from the placental bed.

Blood pressure augmentation and maternal circulating concentrations of angiogenic factors at delivery in preeclamptic and uncomplicated pregnancies

OBJECTIVE The objective of the study was to determine whether blood pressure increases are associated with maternal angiogenic factors in uncomplicated and preeclamptic pregnancies. STUDY DESIGN Associations of blood pressure increases from mid- to late pregnancy with maternal serum concentrations of soluble fms-like tyrosine kinase receptor (sFlt1), soluble endoglin (sEng), and placental growth factor (PlGF) at delivery were analyzed in 43 uncomplicated and 44 preeclamptic pregnancies. RESULTS In uncomplicated pregnancies, increases in diastolic and mean arterial pressure were inversely associated with PlGF at delivery and positively associated with sEng and sFlt1/PlGF ratio. There were no significant associations between blood pressure increases and angiogenic factor concentrations in preeclampsia. CONCLUSION These data suggest that angiogenic factors are involved in blood pressure modulation in normotensive pregnancy and are consistent with the hypothesis that angiogenic balance plays a role in maternal breast cancer risk reduction associated with mid- to late blood pressure increases in uncomplicated pregnancies.

Advanced Glycation End Products in Pregnancies Complicated with Diabetes Mellitus or Preeclampsia

Objective: Preeclampsia (PE) and diabetes mellitus (DM) are associated with oxidative stress. DM is complicated with formation of advanced glycation end products (AGEs), which are associated with oxidative stress. We hypothesized that elevated serum AGE would be found in pregnancies complicated by PE or DM. Methods: Circulating AGEs, 8-isoprostane, vitamin E, and antioxidant capacity were analyzed from study patients. Results: Serum AGE was elevated both in patients with type 1 DM and gestational DM, but not in PE, compared with controls. 8-isoprostane was elevated in patients with type 1 DM and PE compared with controls. Conclusion: AGEs and 8-isoprostane are not elevated in parallel in pregnancies complicated with PE or DM, suggesting biological heterogeneity.

Maternal, gestational and neonatal characteristics and maternal angiogenic factors in normotensive pregnancies.

OBJECTIVE Alterations in maternal circulating angiogenic factors are proposed to result in hypertension and proteinuria and development of preeclampsia. The aim of this study was to explore whether preeclampsia risk factors are associated with maternal angiogenic profile in normotensive pregnancies. STUDY DESIGN Associations of pregnancy characteristics and maternal serum concentrations at delivery of proangiogenic placental growth factor (PlGF), antiangiogenic soluble fms-like tyrosine kinase receptor (sFlt1) and soluble endoglin (sEng), as well as the antiangiogenic ratios sFlt1/PlGF and (sFlt1+sEng)/PlGF were analyzed in 43 normotensive and 44 preeclamptic pregnancies. RESULTS In normotensive pregnancies, increasing maternal age was associated with a more antiangiogenic profile, including lower PlGF concentrations and a higher (sFlt1+sEng)/PlGF ratio (P<0.05). In preeclampsia, shorter length of gestation and lower birth weight percentile were associated with a more antiangiogenic profile. CONCLUSION A greater antiangiogenic profile with older maternal age may suggest a biological mechanism which mediates this preeclampsia risk factor. In preeclampsia, the antiangiogenic state was more pronounced with clinical characteristics indicative of greater disease severity.