Differential expression of lactate dehydrogenase isozymes (LDH) in human placenta with high expression of LDH-A(4) isozyme in the endothelial cells of pre-eclampsia villi

Lactate dehydrogenase (LDH) as an indicator of pre-eclampsia

High blood pressure (higher than 140/90 mm Hg), proteinuria and swelling due to fluid retention are symptoms of preeclampsia, a disease that affects pregnant women after the 20th week of pregnancy. The cytoplasm of cells undergoing anaerobic glycolysis contains the enzyme lactate dehydrogenase or LDH. Therefore, it is of interest to ascertain the blood lactate dehydrogenase levels of pre-eclamptic women, to assess and analyze these levels, to compare lactate dehydrogenase levels in different groups of preeclampsia patients and healthy controls and to examine the role of lactate dehydrogenase in preeclampsia severity ratings. Increased blood lactate dehydrogenase levels are associated with more severe preeclampsia, according to this study's results. Thus, it is crucial to determine lactate dehydrogenase levels in pre-eclamptic women early on so that these patients may get the right medicine and reduce the morbidity and mortality associated with these disorders.

Metabolic pathways of glucose and fructose: II Spatiotemporal expression of genes involved in synthesis and transport of lactate in ovine conceptuses†

Lactate, an abundant molecule in fetal fluids and blood of mammalian species, is often overlooked as a metabolic waste product generated during pregnancy. Most of the glucose and fructose consumed by ovine conceptuses is converted to lactate, but proteins involved in lactate metabolism and transport have not been investigated. This study characterized total lactate produced by ovine conceptuses throughout gestation, as well as expression of mRNAs and proteins involved in lactate metabolism. Lactate increased in abundance in the uterine lumen during the preimplantation period and was more abundant than pyruvate. The abundance of lactate in allantoic and amniotic fluids increased with advancing days of gestation and most abundant on Day 125 of pregnancy (P < 0.05). Lactate dehydrogenase subunits A (converts pyruvate to lactate) and B (converts lactate to pyruvate) were expressed by conceptuses throughout gestation. Lactate is transported via monocarboxylic acid transporters SLC16A1 and SLC16A3, both of which were expressed by the conceptus throughout gestation. Additionally, the interplacentomal chorioallantois from Day 126 expressed SLC16A1 and SLC16A3 and transported lactate across the tissue. Hydrocarboxylic acid receptor 1 (HCAR1), a receptor for lactate, was localized to the uterine luminal and superficial glandular epithelia of pregnant ewes throughout gestation and conceptus trophectoderm during the peri-implantation period of gestation. These results provide novel insights into the spatiotemporal profiles of enzymes, transporters, and receptor for lactate by ovine conceptuses throughout pregnancy.

Development and validation of nomograms to predict clinical outcomes of preeclampsia

Background

Preeclampsia (PE) is one of the most severe pregnancy-related diseases; however, there is still a lack of reliable biomarkers. In this study, we aimed to develop models for predicting early-onset PE, severe PE, and the gestation duration of patients with PE.

Methods

Eligible patients with PE were enrolled and divided into a training (n = 253) and a validation (n = 108) cohort. Multivariate logistic and Cox models were used to identify factors associated with early-onset PE, severe PE, and the gestation duration of patients with PE. Based on significant factors, nomograms were developed and evaluated using the area under the curve (AUC) and a calibration curve.

Results

In the training cohort, multiple gravidity experience (p = 0.005), lower albumin (ALB; p < 0.001), and higher lactate dehydrogenase (LDH; p < 0.001) were significantly associated with early-onset PE. Abortion history (p = 0.017), prolonged thrombin time (TT; p < 0.001), and higher aspartate aminotransferase (p = 0.002) and LDH (p = 0.003) were significantly associated with severe PE. Abortion history (p < 0.001), gemellary pregnancy (p < 0.001), prolonged TT (p < 0.001), higher mean platelet volume (p = 0.014) and LDH (p < 0.001), and lower ALB (p < 0.001) were significantly associated with shorter gestation duration. Three nomograms were developed and validated to predict the probability of early-onset PE, severe PE, and delivery time for each patient with PE. The AUC showed good predictive performance, and the calibration curve and decision curve analysis demonstrated clinical practicability.

Conclusion

Based on the clinical features and peripheral blood laboratory indicators, we identified significant factors and developed models to predict early-onset PE, severe PE, and the gestation duration of pregnant women with PE, which could help clinicians assess the clinical outcomes early and design appropriate strategies for patients.

Angiogenic growth factors, oxidative stress and haematobiochemical measures as predictors of preeclampsia with and without foetal growth restriction: A case-control study in a Ghanaian population

INTRODUCTION

This study compares the angiogenic growth mediators (AGMs), oxidative stress (OS) and haematobiochemical profile as well as foeto-maternal outcomes of preeclampsia (PE) with and without foetal growth restriction (FGR) and the discriminative potential of these markers for identifying these conditions.

METHODS

This hospital-based case-control study recruited a total of 209 women including 109 PE women without FGR and 48 PE women with FGR as cases whereas 52 normotensive pregnant women were recruited as controls. OS and AGMs and haematobiochemical markers were measured for all participants.

RESULTS

The rates of foetal complications including intrauterine foetal death and foetal distress were more common in PE with FGR than PE without FGR (p < 0.05) but maternal complications were comparable across these groups (p > 0.05). Of the haematobiochemical markers, placental growth factors (PIGF), PIGF/8-Isoprostane, sFlt-1/PIGF (AUC = 0.87, p < 0.001), soluble FMS-tyrosine kinase receptor-1 (sFlt-1) (AUC = 0.85, p < 0.001), total antioxidant capacity, 8-isoprostane (AUC = 0.83, p < 0.001) and lactate dehydrogenase (AUC = 0.70, p < 0.001) were more associated and showed at least an acceptable discrimination for PE with FGR against PE only.

DISCUSSION

The occurrence of FGR in PE patients does not necessarily indicate a severe maternal presentation of the condition but a tendency for adverse foetal outcomes. Cumulative assessment of OS and AGMs may provide diagnostic usefulness for distinguishing PE with and without FGR.

Glycolysis: A fork in the path of normal and pathological pregnancy

Glucose metabolism is vital to the survival of living organisms. Since the discovery of the Warburg effect in the 1920s, glycolysis has become a major research area in the field of metabolism. Glycolysis has been extensively studied in the field of cancer and is considered as a promising therapeutic target. However, research on the role of glycolysis in pregnancy is limited. Recent evidence suggests that blastocysts, trophoblasts, decidua, and tumors all acquire metabolic energy at specific stages in a highly similar manner. Glycolysis, carefully controlled throughout pregnancy, maintains a dynamic and coordinated state, so as to maintain the homeostasis of the maternal-fetal interface and ensure normal gestation. In the present review, we investigate metabolic remodeling and the selective propensity of the embryo and placenta for glycolysis. We then address dysregulated glycolysis that occurs in the cellular interactive network at the maternal-fetal interface in miscarriage, preeclampsia, fetal growth restriction, and gestational diabetes mellitus. We provide new insights into the field of maternal-fetal medicine from a metabolic perspective, thus revealing the mystery of human pregnancy.

Transcriptomic profiling in hypoxia-induced trophoblast cells for preeclampsia

This study aimed to identify the expression profile of mRNAs and analyze the associated pathways in hypoxia-induced trophoblast cells to understand the effect of hypoxia on the pathophysiology of preeclampsia (PE). We downloaded two gene expression datasets (GSE47187 and GSE60432) from the Gene Expression Omnibus (GEO) datasets to identify altered transcriptomes. GEO2R, gene ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), and protein-protein interaction (PPI) networks were used to reveal the functional roles and regulatory networks of the differentially expressed genes (DEGs). In total, 224 DEGs (91 upregulated and 133 downregulated) were identified, and the "HIF-1 signaling pathway" was activated in placentas from patients with PE. We validated the expression levels of five proteins in the plasma of NP and PE patients during early or late pregnancy using western blotting. In primary trophoblast cells cultured under hypoxic conditions, 754 DEGs were identified, including 362 upregulated and 392 downregulated genes. These DEGs were associated with the "HIF-1signaling pathway," "response to hypoxia," and several glucose metabolism pathways. In addition, a PPI network was constructed, and an important module, including 18 hub genes, was identified. Finally, we validated 18 hub genes using qRT-PCR. Furthermore, we performed microarray profiling of hypoxia-treated HTR8/SVneo cells (immortalized human first-trimester extravillous trophoblast cells) to validate the DEGs and pathways identified in hypoxia-induced primary trophoblast cells. Our results stress the differential expression profiles of mRNAs in hypoxia-induced trophoblast cells, which provide potential pathophysiological mechanisms for preeclampsia.

A Study on Serum Lactate Dehydrogenase and Uric Acid in Preeclampsia and Eclampsia: Can they Predict Adverse Fetomaternal Outcome?

Background

Hypertensive disorders of pregnancy affect 3%-5% of all pregnancies, contributing immensely to maternal morbidity and mortality. According to the WHO, the incidence of deaths due to preeclampsia and eclampsia in developing and developed countries is 2.8% and 0.4%, respectively. Lactate dehydrogenase (LDH) and uric acid are good predictors of disease severity.

Aim

This study aims to determine the fetomaternal outcome in relation to abnormal serum levels of LDH and uric acid.

Materials and Methods

A cross-sectional study was carried out in 1200 patients with preeclampsia and eclampsia at a tertiary care center over 2 years. Patients were divided into - Group A: patients with normal LDH (≤300 IU/L) and uric acid (<6 mg/dl) (n = 300). Group B: patients with abnormal LDH and uric acid (n = 900), who were further divided into mild and severe preeclampsia and eclampsia. Abnormal serum values were stratified into groups for easier comparison. The results were compared in terms of maternal and perinatal outcomes.

Results

The incidence of preeclampsia and eclampsia in our study is 3.14% and 1.57%, respectively. Significant changes in LDH and uric acid were associated with increased severity of the disease (LDH - 1116.94 ± 4.78; uric acid - 9.2 ± 2.89). Higher incidence of maternal and fetal complications was seen with severe preeclampsia and eclampsia with LDH >800 IU/L and uric acid >6 mg/dl.

Conclusion

Standard antenatal follow-up should be carried out for early detection and prevention of preeclampsia, with strict monitoring of serum uric acid level and LDH. This may reduce the maternal and fetal complications due to preeclampsia.

Overexpression of glycolysis markers in placental tissue of pregnant women with chronic venous disease: a histological study

Chronic Venous Disease (CVD) refers to a wide variety of venous disorders being the varicose veins its most common manifestation. It is well-established the link between pregnancy and the risk of suffering CVD, due to hormonal or haematological factors, especially during the third trimester. In the same manner, previous studies have demonstrated the detrimental effect of this condition in the placental tissue of pregnant women, including in the normal physiology and the metabolomic profile of this organ. In this context, the aim of this study was to evaluate the glucose homeostasis in the placental tissue of women presenting CVD. Through immunohistochemistry, we studied the protein expression of the glucose transporter 1 (GLUT-1), Phosphoglycerate kinase 1 (PGK1), aldolase (ALD), Glyceraldehyde-3-phosphate dehydrogenase (GA3PDH) and lactate dehydrogenase (LDH). Our results have reported a significative increase in the expression of GLUT-1, PGK1, ALD, GA3PDH and the isoenzyme LDHA in placentas of women with CVD. This work has proven for the first-time an altered glucose metabolism in the placental tissue of women affected by CVD, what may aid to understand the pathophysiological mechanisms of this condition in more distant organs such as placenta. Furthermore, our research also supports the basis for further studies in the metabolic phenotyping of the human placenta due to CVD, which may be considered during the late pregnancy in these women.

Evaluation of total LDH and its isoenzymes as markers in preeclampsia

Background

Preeclampsia, a rapidly progressing pregnancy-specific multi-systemic syndrome is globally the leading cause of maternal and neonatal morbidity and mortality. This study aims to evaluate the serum total Lactate dehydrogenase levels in women with preeclampsia when compared to normotensive pregnant women and assess the electrophoretic pattern of the LDH isoenzymes in normal pregnancy, preeclampsia and eclampsia.

Methods

The study, carried out in the Department of Biochemistry of MVJ Medical College, included 30 patients of preeclampsia and 30 normotensive gestational age-matched pregnant women admitted to the Department of OBG. Serum total LDH was analysed by DGKC method. Serum and cord blood samples for isoenzyme distribution analysis were collected from a normal pregnant woman undergoing delivery, a woman with mild eclampsia, two women with eclampsia, and analysed by slab gel electrophoresis followed by activity staining.

Results

LDH was significantly elevated in cases as well as between the case (mild and severe) groups, showed a moderate positive statistically significant correlation with systolic, diastolic blood pressure and a sensitivity of 50% and a specificity of 80%. Further, the isoenzyme pattern showed a decreasing distribution of aerobic forms of LDH in preeclampsia-eclampsia.

Conclusions

Serum total LDH may serve as a robust and affordable marker of preeclampsia. Serum total LDH, along with its isoenzyme profile, might serve as a predictor and a stronger marker of preeclampsia when compared to serum LDH analysis alone. It may also be used to assess the severity of preeclampsia and hence help in predicting and preventing adverse maternal and foetal outcomes.

Risk factors and pregnancy outcomes associated with retinopathy in patients presenting with severe preeclampsia: A retrospective cohort study

The visual system was reported to be affected in over half of patients with preeclampsia (PE), though fundus examination was performed only among patients complaining of visual symptoms. Delayed diagnosis and treatment of PE-related retinopathy may lead to permanent visual impairment. Therefore, we hypothesize that some clinical or laboratory parameters could predict severity of retinal damage.The aim of the study was to explore the risk factors for retinopathy in severe preeclampsia (sPE) and investigate pregnancy outcomes with different degrees of retinopathy.This retrospective cohort study included women with sPE who underwent ophthalmoscopy and delivered after admission to West China Second University Hospital, between June 2013 and December 2016. Clinical and laboratory characteristics were retrieved from medical records. Patients confirmed with retinopathy were followed up with telephones. Multiple logistic regression analysis was performed to identify risk factors of PE-related retinopathy.Five hundred thirty-four patients were included, of which 17.6% having stage-1/2 retinopathy, 14.6% having stage-3/4 retinopathy, and 67.8% having normal retina. Compared with patients without retinopathy, patients with stage 3/4 retinopathy were more likely to have preterm-birth and low-birth-weight babies. Significant risk factors for stage 3/4 retinopathy in sPE included severe hypertension (odds ratio [OR] 2.24, 95% confidence interval [CI]: 1.10-4.56), elevated white blood cell (WBC) counts (OR 1.88, 95% CI: 1.05-3.35), decreased platelet counts (OR 2.12, 95% CI: 1.07-4.48), lactate dehydrogenase (LDH) concentration of >800 IU/L (OR 2.31, 95% CI: 1.05-5.06), low hemoglobin (HGB) concentrations of <110 g/L (OR 3.73, 95% CI: 1.21-11.47), 24-hour proteinuria of 2 to 5 g (OR 6.39, 95% CI: 2.84-14.39), and >5 g (OR 8.66, 95% CI: 3.67-20.44).This study confirms the association between retinopathy and preterm-birth and low-birth weight in sPE. The risk factors for severe PE-related retinopathy, including severe hypertension, platelet and WBC count, HGB and LDH concentration, and proteinuria, are associated with the development of retinopathy. Routine and repeated fundus examination is recommended for maternal monitoring in sPE.

Hydrogen peroxide-mediated oxidative stress induces inflammasome activation in term human placental explants

BACKGROUND

The placenta is a multifunctional organ that can suffer with imbalances between pro- and antioxidant molecules, contributing for inflammatory imbalance. The inflammation generated by oxidative stress may induce inflammasome activation, an essential complex for pro-inflammatory cytokine production.

OBJECTIVE

The aim of this study was to evaluate whether hydrogen peroxide (H₂O₂) mediated oxidative stress induces inflammasome activation on placental explants.

STUDY DESIGN

Tissue cultures of placental explants obtained from normotensive pregnant women were performed in different concentrations of H₂O₂. Gene expressions of NLRP3, caspase-1, IL-1β, TNF-α and IL-10 were evaluated by qPCR. Superoxide dismutase (SOD), catalase, Heat shock protein 70 (Hsp70), Caspase-1, TNF-α, IL-1β, IL-10 and human Chorionic Gonadotropin (hCG) were determined by ELISA.

RESULTS

Concentrations of catalase, Hsp70, hCG and SOD were higher in cultures with 100 and 1000 µM H₂O₂ compared to controls. Gene and protein expressions of TNF-α and IL-1β were elevated in cultures with 1000 μM H₂O₂ compared to controls. This concentration led to inflammasome activation, by increasing gene expressions of NLRP3, caspase-1 and IL-1β. In contrast, gene and protein expressions of IL-10 were reduced at 100 and 1000 μM H₂O₂. Protein expression of caspase-1 was higher in cultures of 100 μM H₂O₂ compared to controls. Treatment with Glybenclamide at 200 μM was used to prevent NLRP3 inflammasome activation. This concentration reduced protein expression of caspase-1 compared to culture with only H₂O₂ and control cultures.

CONCLUSIONS

Our results confirm that H₂O₂ induces oxidative stress on placental explants and demonstrate that cell responses to this stress involve inflammasome activation.

Identification of key microRNAs and genes in preeclampsia by bioinformatics analysis

Preeclampsia is a leading cause of perinatal maternal–foetal mortality and morbidity. The aim of this study is to identify the key microRNAs and genes in preeclampsia and uncover their potential functions. We downloaded the miRNA expression profile of GSE84260 and the gene expression profile of GSE73374 from the Gene Expression Omnibus database. Differentially expressed miRNAs and genes were identified and compared to miRNA-target information from MiRWalk 2.0, and a total of 65 differentially expressed miRNAs (DEMIs), including 32 up-regulated miRNAs and 33 down-regulated miRNAs, and 91 differentially expressed genes (DEGs), including 83 up-regulated genes and 8 down-regulated genes, were identified. The pathway enrichment analyses of the DEMIs showed that the up-regulated DEMIs were enriched in the Hippo signalling pathway and MAPK signalling pathway, and the down-regulated DEMIs were enriched in HTLV-I infection and miRNAs in cancers. The gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes pathway (KEGG) enrichment analyses of the DEGs were performed using Multifaceted Analysis Tool for Human Transcriptome. The up-regulated DEGs were enriched in biological processes (BPs), including the response to cAMP, response to hydrogen peroxide and cell-cell adhesion mediated by integrin; no enrichment of down-regulated DEGs was identified. KEGG analysis showed that the up-regulated DEGs were enriched in the Hippo signalling pathway and pathways in cancer. A PPI network of the DEGs was constructed by using Cytoscape software, and FOS, STAT1, MMP14, ITGB1, VCAN, DUSP1, LDHA, MCL1, MET, and ZFP36 were identified as the hub genes. The current study illustrates a characteristic microRNA profile and gene profile in preeclampsia, which may contribute to the interpretation of the progression of preeclampsia and provide novel biomarkers and therapeutic targets for preeclampsia.

Elevated Liver Enzymes in Cases of Preeclampsia and Intrauterine Growth Restriction

AIM

The aim of this study was to evaluate biochemical parameters in serum of women with preeclampsia and IUGR.

MATERIAL AND METHODS

A clinical prospective study was conducted and included 120 pregnant women divided in two groups: non IUGR group included healthy pregnant women (n=60) and IUGR group included pregnant women with preeclampsia and IUGR (n=60). Outcome measures were following values of biochemical parameters in serum of mother and fetuses: aspartate aminotransferase (AST), alanine aminotransferase (ALT), lactate dehydrogenase (LDH), bilirubin (indirect and direct) and cholesterol. A blood for analysis was drawn from the cubital vein of mothers and the umbilical vein of the fetuses during delivery period.

RESULTS

The mean of maternal age was 30.0±6.1 years in women with preeclampsia and IUGR and 28.1±5.1 years in healthy pregnant women, p > 0.05. The most of women with preeclampsia and IUGR had grade III of placental maturation (48.3%). There is a significant association between the placental maturation and the diagnosis, p < 0.001. There was a statistically significant difference in body mass of newborns between IUGR and non IUGR groups, p < 0.001. There was a significant statistically difference in serum value of AST, ALT, LDH and total cholesterol between women with preeclampsia and IUGR and healthy pregnant women (all p < 0.001).

CONCLUSION

Measurement of AST, ALT, LDH, and total cholesterol in serum of pregnant women and newborns with IUGR allows the differentiation and threatening risk of perinatal complications due to hypoxia.

LDH (Lactate Dehydrogenase): A Biochemical Marker for the Prediction of Adverse Outcomes in Pre-eclampsia and Eclampsia

OBJECTIVE

The aim of the study was to find out the role of Serum lactate dehydrogenase in prediction of adverse outcomes of PE & E i.e., severity of disease and occurrence of complications.

MATERIALS AND METHODS

This study was conducted in the Department of Obstetrics and Gynaecology, MGM Medical College, Indore. A total of 200 women were studied; they were divided into control (n = 100), severe pre-eclampsia (n = 32), eclampsia (n = 68). Demographic and hematological parameters were studied including LDH levels.

RESULTS

The incidence of severe pre-eclampsia-1.2 % & Eclampsia 2.7 %, PE & E patients were significantly younger, with low gravidity and parity. They had significantly increased systolic and diastolic pressure, liver enzymes, uric acid, urine albumin, and LDH levels. Serum urea and creatinine were normal in majority of cases. The symptoms and complications of PE along with perinatal mortality were increased significantly in patients with LDH >800 IU/l compared with those who had lower levels. Complications like Retinopathy, ARF, Abruptio, DIC, CVA, MODS, Shock were also associated with high level of serum LDH >800 IU/L. Low birth weight of babies was also associated with high level of serum LDH levels in PE & E patients. The incidence of poor perinatal outcome was higher in PE & E patients with high serum LDH level (>600 IU/L).

CONCLUSION

LDH is the earliest marker seen in blood during hypoxia and oxidative stress. It is a useful biochemical marker that reflects the severity of and the occurrence of complications of PE & E; these are preventable if identified at an earlier stage and adequately managed at a higher center. Test is easily available, so screening of all cases of PE & E with LDH levels must be made mandatory.

Lactate dehydrogenase-B is silenced by promoter methylation in a high frequency of human breast cancers

OBJECTIVE

Under normoxia, non-malignant cells rely on oxidative phosphorylation for their ATP production, whereas cancer cells rely on Glycolysis; a phenomenon known as the Warburg effect. We aimed to elucidate the mechanisms contributing to the Warburg effect in human breast cancer.

EXPERIMENTAL DESIGN

Lactate Dehydrogenase (LDH) isoenzymes were profiled using zymography. LDH-B subunit expression was assessed by reverse transcription PCR in cells, and by Immunohistochemistry in breast tissues. LDH-B promoter methylation was assessed by sequencing bisulfite modified DNA.

RESULTS

Absent or decreased expression of LDH isoenzymes 1-4, were seen in T-47D and MCF7 cells. Absence of LDH-B mRNA was seen in T-47D cells, and its expression was restored following treatment with the demethylating agent 5'Azacytadine. LDH-B promoter methylation was identified in T-47D and MCF7 cells, and in 25/25 cases of breast cancer tissues, but not in 5/5 cases of normal breast tissues. Absent immuno-expression of LDH-B protein (<10% cells stained), was seen in 23/26 (88%) breast cancer cases, and in 4/8 cases of adjacent ductal carcinoma in situ lesions. Exposure of breast cancer cells to hypoxia (1% O(2)), for 48 hours resulted in significant increases in lactate levels in both MCF7 (14.0 fold, p = 0.002), and T-47D cells (2.9 fold, p = 0.009), but not in MDA-MB-436 (-0.9 fold, p = 0.229), or MCF10AT (1.2 fold, p = 0.09) cells.

CONCLUSIONS

Loss of LDH-B expression is an early and frequent event in human breast cancer occurring due to promoter methylation, and is likely to contribute to an enhanced glycolysis of cancer cells under hypoxia.

Circulating and utero-placental adaptations to chronic placental ischemia in the rat

While utero-placental insufficiency is associated with adverse outcomes for both mother and fetus, many of the maternal-fetal adaptations during pregnancy in models of fetal compromise remain unclear. The purpose of this study was to determine if chronically reduced uterine perfusion pressure (RUPP) during days 14-19 of gestation alters feto-placental growth differentially from the cervical to ovarian ends of the uterus and generates metabolic adaptations such as increased blood lactate (BLa) concentrations and lactate transporter expression in the placenta. Fetal growth restriction was evident, placental efficiency (fetal weight/placental weight) decreased (4.7 ± 0.35 vs. 5.9 ± 0.30; P < 0.05) and fetal growth pattern within the uterus was altered in the RUPP compared to the normal pregnant (NP) rats. Blood lactate concentrations were increased (3.3 ± 0.3 vs. 2.1 ± 0.4 mmol/l; P < 0.05) in NP compared to virgin rats, and in RUPP compared to NP (5.0 ± 0.6 vs. 3.3 ± 0.3 mmol/l; P < 0.05). Lactate concentration was increased (10.0 ± 0.6 vs. 7.1 ± 0.8 mmol/l; P < 0.05) in the media from hypoxic compared to normoxic BeWo cells. No changes in expression of placental MCT1, 2, or 4 were observed between RUPP and NP rats. RUPP resulted in decreased plasma leptin (2.0 ± 0.3 vs. 3.1 ± 0.4; P < 0.05) but no change in IGF-1 compared to NP. The present data indicate chronic placental ischemia results in numerous endocrine and metabolic changes during late pregnancy in the rat and that the RUPP model has differential effects on fetal growth depending on uterine position.

Existence of the lymphatic system in the primate corpus luteum

To date, there have been no detailed studies on the lymphatic system in the primate corpus luteum (CL); early reports suggested that the presence of this "secondary circulation" in luteal tissue is species-dependant. Therefore, studies were designed to determine if (a) lymphatic vessels exist, and (b) recently discovered lymphangiogenic factors and their receptor are expressed in the macaque CL during the menstrual cycle. Immunohistochemistry (IHC) detected the lymphatic endothelial cell marker, lymphatic vessel endothelial hyaluronan receptor 1 (LYVE1), in some endothelial cells and vessels within the ovarian stroma and theca layer of preovulatory follicles and in the CL. Dual fluorescent IHC demonstrated that LYVE1 co-localized with another lymphatic endothelial cell marker D2-40, but a blood vascular endothelial cell marker (von Willebrand Factor, VWF) was in different cells. The numbers and staining intensity of LYVE1-positive cells in the CL appeared to increase from early to mid luteal phase, and remained elevated thereafter. RT-PCR detected cDNA fragments for mRNAs encoding VEGFC, FIGF, and their receptor FLT4 in CL. Real-time PCR analyses revealed similar patterns of VEGFC and FLT4 expression during the luteal lifespan; mRNA levels increased (p < 0.05) from early to mid luteal phase and decreased (p < 0.05) by late luteal phase. In contrast, FIGF levels were elevated initially, declined (p < 0.05) at mid luteal phase, and then increased (p < 0.05) to very late luteal phase. The data strongly suggest that lymphatic vessels are present in the primate CL, and that the VEGFC/FIGF-FLT4 system regulates lymphangiogenesis and luteal structure-function during the menstrual cycle.

Hypoxia and Lactate Production in Trophoblast Cells

The etiology of preeclampsia is unknown but is thought to be related to hypoxia in the placenta. We previously reported that the enzyme lactate dehydrogenase (LDH) has increased activity and gene expression in placentas from preeclamptic pregnancies [Tsoi SCM, Zheng J, Xu F, Kay HH. Differential expression of lactate dehydrogenase isozymes (LDH) in human placenta with high expression of LDH-A(4) isozyme in the endothelial cells of pre-eclampsia villi. Placenta 2001;22:317-22]. LDH is responsible for pyruvate conversion to lactate through glycolysis. In this study, we further investigated the role of hypoxia in primary trophoblast cells and a cultured cell line, JEG3 cells, to obtain a better understanding of how it affects the activities of lactate dehydrogenase, lactate production and regulatory genes, as a possible model for preeclampsia. Primary trophoblast cells and JEG3 cells were cultured under 1% oxygen. At 6, 12 and 24h, cells were analyzed for LDHA and LDHB isozyme activities, mRNA and protein expression compared to standard culture conditions. Lactate was measured from cell medium. The hypoxia inducible transcription factor (HIF-1alpha) protein expression was confirmed by western blot. Two lactate transporters (MCT1 and MCT4) mRNA and protein expression were also studied under hypoxia. Finally, lactate was measured in plasma obtained from patients with severe preeclampsia. Under hypoxic conditions, LDHA mRNA is increased in primary trophoblast cells and JEG3 cells. The HIF-1alpha protein expression is higher in hypoxia-treated JEG3 cells than control. LDHA isozyme activity and its protein expression are increased most significantly at 24h of culture under hypoxia. However, LDHB protein is unchanged while its mRNA is decreased. Lactate secretion from JEG3 cells under hypoxia is increased, as is the lactate levels in the plasma from preeclampsia patients. Of the two lactate transporters studied, MCT4 mRNA and protein level are increased under hypoxia. Our findings support the role of hypoxia in inducing HIF-1alpha activity in trophoblasts and increasing LDH transcription as well as its activity. Higher levels of lactate are produced and secreted which may contribute to the higher lactate levels in plasma of preeclamptic patients. These mechanisms may be important in the pathophysiology of preeclampsia.

Placental HIF-1 alpha, HIF-2 alpha, membrane and soluble VEGF receptor-1 proteins are not increased in normotensive pregnancies complicated by late-onset intrauterine growth restriction

Inadequate trophoblast invasion and spiral artery remodeling leading to poor placental perfusion are believed to underlie the pregnancy pathologies preeclampsia (PE) and intrauterine growth restriction (IUGR). The main objective of this study was to investigate hypoxia-inducible transcription factor-alpha (HIF-alpha) and downstream genes (VEGF receptor-1) Flt-1 and soluble fms-like tyrosine kinase 1 (sFlt-1) proteins in IUGR placentas. Placentas from normal pregnant (NP; n = 18), PE (n = 18), and IUGR (n = 10) patients were investigated. Normotensive patients with IUGR delivered babies at >or= 37 wk of gestation with birth weights of <10% and asymmetrical growth. HIF-1 alpha, -2 alpha, Flt-1, and sFlt-1 protein, and mRNA were assessed by Western and Northern blot analyses, respectively. The results are expressed as ratios of the densitometric values for each pair of pathologic and normal placentas, a ratio of 1.0 indicating no difference. Comparable to our earlier studies, the PE/NP ratios for HIF-1 alpha, -2 alpha, and Flt proteins were significantly increased by 50-100% (all P < 0.01 vs. 1.0). Unexpectedly, the IUGR/NP ratios for HIF-1 alpha and -2 alpha proteins were 1.03 +/- 0.07 and 0.96 +/- 0.16, respectively, and for Flt and sFlt were 1.14 +/- 0.15 and 0.95 +/- 0.12, respectively (all P = not significant vs. 1.0). Northern blot analysis revealed comparable levels of HIF-alpha mRNA in abnormal and normal placentas. In contrast to PE, HIF-alpha proteins and regulated genes are not increased in placentas from normotensive pregnant women delivering small, asymmetrically grown babies >or= 37 wk of gestation. The absence of an increase in HIF-alpha protein is not due to insufficient HIF-alpha mRNA for protein synthesis. Thus, the placentas from women with PE and late IUGR are fundamentally different at the molecular level.

Lactate dehydrogenase isoform activity mapping in patients with intra-amniotic infection

OBJECTIVE

Five distinct lactate dehydrogenase isoenzymes have been described. We sought to illustrate the specific amniotic fluid lactate dehydrogenase isoenzyme activity profiles in women with intra-amniotic infection.

STUDY DESIGN

Amniotic fluid was retrieved from 82 women who were stratified in the following groups: (1) positive amniotic fluid cultures (n = 23 women; gestational age, 26 weeks [range, 21-32 weeks]); (2) negative amniotic fluid cultures (n = 22 women; gestational age, 30 weeks [range, 16-36 weeks]); (3) second trimester control (normal genetic karyotype; n = 17 women; gestational age, 18 weeks [range, 16-22 weeks]); and (4) third trimester control (fetal lung maturity testing; n = 20 women; gestational age, 36 weeks [range, 31-38 weeks]). The optical density of each isoform was determined relative to a standard with 5 known lactate dehydrogenase isoenzyme activities. Total lactate dehydrogenase activity was measured by the clinical laboratory immediately after retrieval and by a kinetic UV spectrophotometric assay at the time of the isoelectric focusing.

RESULTS

Infection increased total lactate dehydrogenase activity: positive amniotic fluid cultures (median, 762.4 [range, 169.3-3374.8]) vs negative amniotic fluid cultures (median, 203.7 [range, 57.8-1939.3]; U/L; P < .001]). Lactate dehydrogenase isoform profiling identified significant and specific increases in lactate dehydrogenase isoforms 3, 4 (P < .01), and 5 (P < .05) in positive amniotic fluid cultures compared to the negative amniotic fluid cultures group. A selective up-regulation in lactate dehydrogenase isoform 5 was identified at term in healthy subjects.

CONCLUSION

Intra-amniotic infection is characterized by an increase in the activities of lactate dehydrogenase isoforms 3, 4, and 5; advancing gestational age demonstrates an up-regulation of isoform 5 only.

Lactate dehydrogenase-B is silenced by promoter hypermethylation in human prostate cancer

In order to identify novel candidates associated with prostate cancer metastasis, we compared the proteomic profile of the poorly metastatic human prostate cancer cell line LNCaP, with its highly metastatic variant LNCaP-LN3, by two-dimensional gel electrophoresis. A major protein spot (pI of 5.9 and molecular weight of 37 kDa) was seen in LNCaP cells, but not in LNCaP-LN3 cells and was identified as lactate dehydrogenase-B (LDHB), by tandem mass spectrometry. Furthermore, enzyme kinetic assays and zymography showed a higher LDH enzyme activity in LNCaP cells compared with LNCaP-LN3. Bisulphite-modified DNA sequencing showed promoter hypermethylation in LNCaP-LN3 cells but not in LNCaP, Du145, PC3, CWR22 or BPH45 cells. Treatment of LNCaP-LN3 cells with 5'-azacytidine caused re-expression of LDHB transcripts. In tissues, LDHB promoter hypermethylation occurred at a higher frequency in prostate cancer, 14/ 31 (45%), compared to adjacent nonmalignant or benign tissue, 2/19 (11%) (P < 0.025). Immunohistochemistry showed a higher frequency of LDHB expression in benign or non-malignant tissues, 59/ 73 (81%), compared to cancer cases, 3/53 (6%) (P < 0.001). Absent LDHB expression was also seen in 7/7 (100%) cases of metastatic cancer in bone. Our data are the first to show loss of LDHB expression in prostate cancer, the mechanism of which appears to involve promoter hypermethylation.

Gene expression profiling of human placentas from preeclamptic and normotensive pregnancies

The aim of this study was to investigate patterns of gene expression in placental samples from patients with preeclampsia (PE), persistent bilateral uterine artery notching (without PE), and normal controls. This study included placental tissue from nine women with PE, seven with uncomplicated pregnancies and five with bilateral uterine artery notching in Doppler velocimetry tracings. Human cDNA microarrays with 6500 transcripts/genes were used and the results verified with real-time PCR and in-situ hybridization. Multidimensional scaling method and random permutation technique demonstrated significant differences among the three groups examined. Within the 6.5K arrays, 6198 elements were unique cDNA clones representing 5952 unique UniGenes and 5695 unique LocusLinks. Multidimensional scaling plots showed 5000 genes that met our quality criteria; among these, 366 genes were significantly different in at least one comparison. Differences in three genes of interest were confirmed with real-time PCR and in-situ hybridization; acid phosphatase 5 was shown to be overexpressed in PE samples and calmodulin 2 and v-rel reticuloendotheliosis viral oncogene homolog A (RELA) were downregulated in PE and uterine artery notch placentas. In conclusion downregulation of RELA and calmodulin 2 might represent an attempt by the placenta to compensate for elevations in intracellular calcium, possibly caused by hypoxia and/or apoptosis, in both pregnancies with uterine artery notching and preeclampsia.

Identification of epithelial auto-antigens associated with periodontal disease

We previously reported evidence that patients with periodontitis have serum antibodies to oral Gram positive bacteria that are cross-reactive with epithelial antigens. In the present report cross-reactive epithelial antigens including CD24, lactate dehydrogenase A [LDM-A], antioxidant protein 2 [AOP 2] and nuclear factor of activated T cells 5 [NFAT 5], were identified by screening a cDNA expression library with pooled patient sera. Titres of antibodies to CD24 peptide correlated negatively with indices of periodontal disease severity. Strong expression of CD24 in the reactive periodontal epithelium and inflamed gingival attachment contrasted with low to undetectable expression in the external gingival epithelium. In periodontitis, a local action of these auto-reactive antibodies could modulate the regulatory potential associated with expression of CD24 in this epithelium.

Inhibin, activin, follistatin, activin receptors and β-glycan gene expression in the villous tissue of miscarriage patients

Maternal circulating levels of inhibin A are significantly lower in patients with clinical symptoms of miscarriage. The objective of this study was to quantify relative expression of inhibin alpha, inhibin/activin betaA, betaB, betaC, follistatin, activin receptors and beta-glycan genes and content of inhibin A, activin A and follistatin protein in villous tissue of first trimester miscarriages and gestation-matched normal pregnancies. Twelve women with clinical symptoms of miscarriage were matched with 12 normal pregnancies for gestational age. Total RNA was isolated from placental samples. Complementary DNA produced by reverse transcription was used in the real-time PCR to quantify the expression of the genes. The ratio between the target and rRNA 18S was calculated to provide relative gene expression. Villous tissue homogenates were used for the determination of the content of inhibin A, activin A and follistatin protein. Maternal serum was assayed for inhibin A, activin A and follistatin. All villous samples expressed inhibin alpha, inhibin/activin betaA, betaB, betaC, follistatin, activin receptors (ACTRIA, ACTRIB, ACTRIIA, ACTRIIB) and beta-glycan genes. There was no significant difference in the relative expression of these genes between the groups. Villous content of inhibin A, activin A and follistatin were also not different between the two groups. Maternal serum levels of inhibin A were significantly lower in the miscarriage group compared to the controls. The decreased maternal levels of inhibin A in miscarriage patients could be due to a decrease in placental mass prior to embryonic demise. This finding also confirms that the trophoblast is the major source of inhibin A after the luteo-placental shift in early pregnancy.

Searching for preeclampsia genes: the current position

Although there is substantial evidence that preeclampsia has a genetic background, the complexity of the processes involved and the fact that preeclampsia is a maternal-fetal phenomenon does not make the search for the molecular basis of preeclampsia genes easy. It is possible that the single phenotype 'preeclampsia' in fact should be divided into different sub-groups on genetic or biochemical level. In the present review, the preeclampsia phenotype and its pathophysiologic features are discussed. Family studies and postulated inheritance models are summarized. A systematic overview is given on the numerous candidate gene studies and gene-expression studies performed so far and on the currently available genome-wide scan data. Despite extensive research the molecular genetic basis of preeclampsia remains unclear. Future studies will hopefully enhance our insights in the molecular pathogenesis of preeclampsia.

Co-expression of vascular endothelial growth factor and neuropilin-1 in ovine feto-placental artery endothelial cells

Vascular endothelial growth factor (VEGF) is a key regulator for placental angiogenesis and vascular functions via activating two high affinity tyrosine-kinase receptors, VEGF receptor-1 (VEGFR-1) and -2 (VEGFR-2). Recently, a specific VEGF165 receptor, neuropilin-1 (NP-1), was also identified in endothelial cells and upon VEGF binding, NP-1, synergistically with VEGFR-2, enhances VEGF-induced cell proliferation and migration. To evaluate the role of VEGF and NP-1 in regulating fetoplacental angiogenesis and endothelial function, an ovine fetal placental artery endothelial (OFPAE) cell line was established. In this study, an OFPAE cell cDNA library was constructed. Two positive clones for VEGF and one for NP-1 were isolated from the OFPAE cell cDNA library, and their partial 3' sequences were identified. The sequence of VEGF cDNA insert had 98% homology to the reported ovine VEGF (GenBank accesssion # X89506). The partial NP-1 cDNA sequence included a portion of the protein coding region and a complete 3' untranslated region (UTR), and had 90% homology to human NP-1 (GenBank accession # AF016050). The predicted amino acid sequence of ovine NP-1 was 97-98% identical to human (GenBank accession # AAC12921.1), mouse (GenBank accession # NP_032763), and rat (GenBank accession # AAC53345.1) NP-1. Two CU-rich stabilizing and two consensus destabilizing elements 5'-AUUUA-3' were identified in the 3' UTR of ovine NP-1 cDNA sequence. These elements are the potential binding sites for mRNA-binding proteins which may regulate the stability of NP-1 mRNA. Expression of VEGF and NP-1 in OFPAE cells and fetal placentas was confirmed by Northern and Western blot analyses. Using PCR analysis, we also identified partial sequences of multiple VEGF isoforms (VEGF188, 183, 164, and 120) as well as VEGFR-1, VEGFR-2, and neuropilin-2 (NP-2) from the OFPAE cell cDNA library. These results indicate that multiple isoforms of VEGF are expressed in OFPAE cells. Moreover, we also identified, for the first time, a complete 3' UTR of NP-1 cDNA in any species. Together with expression of VEGF and VEGF receptors in OFPAE cells, we propose that there is an autocrine mechanism by which VEGF regulates fetal placental angiogenesis and other functions of endothelial cells.

Injection of Soluble Vascular Endothelial Growth Factor Receptor 1 into the Preovulatory Follicle Disrupts Ovulation and Subsequent Luteal Function in Rhesus Monkeys1

Remarkable changes in vascular permeability and neovascularization occur within the ovulatory, luteinizing follicle. To evaluate the importance of vascular endothelial growth factor/vascular permeability factor (VEGF/VPF) in periovulatory events, sequential experiments were designed in which vehicle (PBS/0.1% BSA; controls, n = 13) or a low dose (1.5 micro g; n = 4) or a high dose (7.5 micro g; n = 4) of a VEGF antagonist, soluble VEGF receptor 1 (sVEGFR1) chimera, was injected directly into the preovulatory follicle of rhesus monkeys the day before (Day -1) or the day of (Day 0) the midcycle LH surge during spontaneous menstrual cycles. After vehicle injection, animals typically exhibited patterns and levels of serum progesterone (P(4)) that were comparable to those of untreated animals in our colony. Following low-dose sVEGFR1 injection, serum P(4) levels were diminished in two of four animals from the early to midluteal phase, but were similar to vehicle controls thereafter. In contrast, high-dose sVEGFR1 injection decreased serum P(4) levels throughout the luteal phase compared with levels in controls (P < 0.05), but it did not cause premature menstruation. Control follicles displayed indices of rupture (protruding stigmata) and luteinization. However, sVEGFR1-injected follicles exhibited signs of distension (torn surface epithelium/tunica albuginea) and luteinization, but not necessarily timely ovulation. Histological evaluation of serial sections from ovaries removed on Day 3 after treatment revealed that all (n = 3) vehicle-injected follicles ovulated, whereas half (n = 3 of 6) the sVEGFR1-injected follicles failed to ovulate and still contained an oocyte in the antrum. No appreciable differences were apparent between treatment groups in numbers of cells in luteal tissue (Day 3 or 6 after treatment) that stained positive for immunochemical or histochemical markers of proliferative (Ki67), endothelial (platelet endothelial cell adhesion molecule 1), and steroidogenic (3beta-hydroxysteroid dehydrogenase) cells. However, there was a dose-dependent increase (P < 0.05) in extracellular space in the corpus luteum by midluteal phase in sVEGFR1-treated animals. The data suggest that acute exposure to a VEGF antagonist can impair ovulation, and the subsequent development and functional capacity of the primate corpus luteum. The results are consistent with a critical role for VEGF in normal ovarian function during the periovulatory interval in primates.