A1M Ameliorates Preeclampsia-Like Symptoms in Placenta and Kidney Induced by Cell-Free Fetal Hemoglobin in Rabbit.

Preeclampsia is one of the most serious pregnancy-related diseases and clinically manifests as hypertension and proteinuria after 20 gestational weeks. The worldwide prevalence is 3-8% of pregnancies, making it the most common cause of maternal and fetal morbidity and mortality. Preeclampsia lacks an effective therapy, and the only "cure" is delivery. We have previously shown that increased synthesis and accumulation of cell-free fetal hemoglobin (HbF) in the placenta is important in the pathophysiology of preeclampsia. Extracellular hemoglobin (Hb) and its metabolites induce oxidative stress, which may lead to acute renal failure and vascular dysfunction seen in preeclampsia. The human endogenous protein, α1-microglobulin (A1M), removes cell-free heme-groups and induces natural tissue repair mechanisms. Exogenously administered A1M has been shown to alleviate the effects of Hb-induced oxidative stress in rat kidneys. Here we attempted to establish an animal model mimicking the human symptoms at stage two of preeclampsia by administering species-specific cell-free HbF starting mid-gestation until term, and evaluated the therapeutic effect of A1M on the induced symptoms. Female pregnant rabbits received HbF infusions i.v. with or without A1M every second day from gestational day 20. The HbF-infused animals developed proteinuria and a significantly increased glomerular sieving coefficient in kidney that was ameliorated by co-administration of A1M. Transmission electron microscopy analysis of kidney and placenta showed both intracellular and extracellular tissue damages after HbF-treatment, while A1M co-administration resulted in a significant reduction of the structural and cellular changes. Neither of the HbF-treated animals displayed any changes in blood pressure during pregnancy. In conclusion, infusion of cell-free HbF in the pregnant rabbits induced tissue damage and organ failure similar to those seen in preeclampsia, and was restored by co-administration of A1M. This study provides preclinical evidence supporting further examination of A1M as a potential new therapy for preeclampsia.

A1M/α1-microglobulin protects from heme-induced placental and renal damage in a pregnant sheep model of preeclampsia.

Preeclampsia (PE) is a serious pregnancy complication that manifests as hypertension and proteinuria after the 20(th) gestation week. Previously, fetal hemoglobin (HbF) has been identified as a plausible causative factor. Cell-free Hb and its degradation products are known to cause oxidative stress and tissue damage, typical of the PE placenta. A1M (α1-microglobulin) is an endogenous scavenger of radicals and heme. Here, the usefulness of A1M as a treatment for PE is investigated in the pregnant ewe PE model, in which starvation induces PE symptoms via hemolysis. Eleven ewes, in late pregnancy, were starved for 36 hours and then treated with A1M (n = 5) or placebo (n = 6) injections. After injections, the ewes were re-fed and observed for additional 72 hours. They were monitored for blood pressure, proteinuria, blood cell distribution and clinical and inflammation markers in plasma. Before termination, the utero-placental circulation was analyzed with Doppler velocimetry and the kidney glomerular function was analyzed by Ficoll sieving. At termination, blood, kidney and placenta samples were collected and analyzed for changes in gene expression and tissue structure. The starvation resulted in increased amounts of the hemolysis marker bilirubin in the blood, structural damages to the placenta and kidneys and an increased glomerular sieving coefficient indicating a defect filtration barrier. Treatment with A1M ameliorated these changes without signs of side-effects. In conclusion, A1M displayed positive therapeutic effects in the ewe starvation PE model, and was well tolerated. Therefore, we suggest A1M as a plausible treatment for PE in humans.

PP010. Alpha-1-microglobulin protects from heme induced placenta and kidney damage in a pregnant ewe model for preeclampsia.

INTRODUCTION: Previous gene expression analysis have identified fetal hemoglobin (HbF) as a plausible etiological factor in preeclampsia. Free hemoglobin and its degradation products, e.g. heme, are known to cause oxidative stress, tissue damage, and vaso-constriction, typical findings in preeclampsia. OBJECTIVE: To study alpha-1-microglobulin (A1M), an endogenous radical scavenger and heme-binder, as a potential treatment for preeclampsia using the pregnant ewe preeclampsia model. Free Hb and heme are known to take part in the pathology of this model and therefor well suited for evaluation of recombinant A1M as a therapy. METHODS: 11 pregnant ewes, at gestational age 125-131 days, were acclimatized for 36h and then starved for another 36h to induce preeclampsia symptoms. At the end of starvation period, they were treated either with placebo (n=6) or A1M injections (n=5). After injections, food was re-introduced and ewes further followed for 72h. The ewes were sacrificed the 6th day after beginning of acclimatization. Throughout the 6 days, the animals were monitored for blood pressure and different blood and urine parameters. Whole blood, kidney and placenta tissue samples were collected from the ewes. Gene expression analysis, blood analysis, histology and electron microscopy were used to evaluate the therapeutic effects of A1M. RESULTS: Starvation increased the amount of free heme in the blood. The ultrastructure of the placenta and kidney were damaged in a way similar to what previously have been described for PE. The glomeruli and the tubuli were damaged which was reflected by increased Ficol clearance and increased plasma creatinine levels. Treatment with A1M significantly normalized the kidney functions. The most profound changes on gene expression level were found in white blood cells in the starved animals. Starvation decreases mRNA expression for anti-oxidants such as CAT (P=0.04), SOD1 (P=0.008), SOD2 (1.8-fold) as well as angiogenetic factors such as VEGF (P=0.02) and HGF (1.6-fold). A1M treatment rescued the decreased expression of SOD2 (P=0.04) and HGF (2-fold). CONCLUSION: A1M is well tolerated and shows high potential as a treatment for PE-like symptoms in the pregnant ewe model for PE.

The G protein-coupled estrogen receptor 1 (GPER/GPR30) does not predict survival in patients with ovarian cancer.

BACKGROUND: Even though ovarian tumors are not generally considered estrogen-sensitive, estrogens may still have an impact on ovarian tumor progression. The recently identified trans-membrane estrogen receptor GPER is involved in rapid estrogen signaling. Furthermore, it binds selective estrogen receptor modulators with agonistic effect, which could explain tamoxifen controversies. METHODS: GPER mRNA was assayed with quantitative real-time PCR (qPCR) in 42 primary ovarian tumors and 7 ovarian cancer cell lines. ERα and ERß mRNA were analyzed for comparison. GPER protein was semi-quantified with densitometric scanning of Western blots and its tissue distribution analyzed with immunohistochemistry (IHC) in 40 ovarian tumors. In addition, IHC was evaluated in a tissue microarray (TMA) of 150 primary malignant ovarian tumors. RESULTS: All tumor samples contained GPER mRNA. The content of mRNA was not different between benign and malignant tumors, but one third of malignant samples over-expressed GPER mRNA. The content of ERα mRNA was higher in malignant than in benign tumors, whereas ERß mRNA was higher in benign than in malignant tumors. GPER mRNA was detected in all seven ovarian cancer cell lines with highest levels in TOV21G and TOV112D cells. Similar expression pattern was seen for ERß mRNA. Western blot demonstrated GPER protein in all tumor samples. Semi-quantification showed no difference between benign and malignant tumors, but about one third of malignant samples over-expressed GPER protein. GPER staining was localized mainly in epithelial cells. In the TMA study we found no correlation between GPER staining and clinical stage, histological grade or patient survival. CONCLUSIONS: GPER mRNA as well as GPER protein is present in both benign and malignant ovarian tumor tissue. About one third of malignant tumors over-expressed both GPER mRNA and protein. This, however, correlated neither with histological or clinical parameters nor with patient survival.