Altered decorin leads to disrupted endothelial cell function: a possible mechanism in the pathogenesis of fetal growth restriction?

OBJECTIVE: Fetal growth restriction (FGR) is a key cause of adverse pregnancy outcome where maternal and fetal factors are identified as contributing to this condition. Idiopathic FGR is associated with altered vascular endothelial cell functions. Decorin (DCN) has important roles in the regulation of endothelial cell functions in vascular environments. DCN expression is reduced in FGR. The objectives were to determine the functional consequences of reduced DCN in a human microvascular endothelial cell line model (HMVEC), and to determine downstream targets of DCN and their expression in primary placental microvascular endothelial cells (PLECs) from control and FGR-affected placentae. APPROACH: Short-interference RNA was used to reduce DCN expression in HMVECs and the effect on proliferation, angiogenesis and thrombin generation was determined. A Growth Factor PCR Array was used to identify downstream targets of DCN. The expression of target genes in control and FGR PLECs was performed. RESULTS: DCN reduction decreased proliferation and angiogenesis but increased thrombin generation with no effect on apoptosis. The array identified three targets of DCN: FGF17, IL18 and MSTN. Validation of target genes confirmed decreased expression of VEGFA, MMP9, EGFR1, IGFR1 and PLGF in HMVECs and PLECs from control and FGR pregnancies. CONCLUSIONS: Reduction of DCN in vascular endothelial cells leads to disrupted cell functions. The targets of DCN include genes that play important roles in angiogenesis and cellular growth. Therefore, differential expression of these may contribute to the pathogenesis of FGR and disease states in other microvascular circulations.

The expression of placental proteoglycans in pre-eclampsia.

BACKGROUND/AIMS: Pre-eclampsia (PE) is one of the leading causes of maternal and perinatal morbidity and mortality. PE is defined clinically as the onset of maternal hypertension and proteinuria following 20 weeks of gestation. It is associated with altered maternal uterine decidual spiral artery remodelling, which may lead to reduced blood flow and increased thrombosis within the uteroplacental vasculature. Proteoglycans (PGs) are macromolecules which have (in combination with glycosaminoglycans) important anticoagulant roles in vascular endothelial environments, including the uteroplacental circulation. The hypothesis under consideration in this study was that differential expression of placental PGs may be associated with PE. METHODS: PE and control placental samples were collected with ethics approval and patient consent. RNA and protein were extracted and real-time PCR and Western immunoblotting were performed to determine the expression of the PGs in the samples. RESULTS: Of the nine PGs investigated, none showed increased expression, whereas the mRNA and protein expression of five of them was significantly decreased in the placentae of pre-eclamptic women compared to gestation-matched controls. CONCLUSION: Therefore, the results of this study support the hypothesis that a placental PG deficiency may contribute to the placental thrombotic lesions characteristic of PE.

The PAI-1 4G/5G polymorphism is not associated with an increased risk of adverse pregnancy outcome in asymptomatic nulliparous women.

BACKGROUND: Plasminogen activator inhibitor type 1 (PAI-1) is an important regulator of fibrinolysis. A common deletion polymorphism that results in a sequence of 4G instead of 5G in the promoter region of the gene is associated with a small increase in the risk of venous thromboembolism. Its potential association with adverse pregnancy events remains controversial. OBJECTIVE: We aimed to assess the impact of the 4G PAI-1 polymorphism on pregnancy outcomes in women who had no prior history of adverse pregnancy outcomes or personal or family history of venous thromboembolism. PATIENTS/METHODS: This study represents a secondary investigation of a prior prospective cohort study investigating the association between inherited thrombophilias and adverse pregnancy events in Australian women. Healthy nulliparous women were recruited to this study prior to 22 weeks gestation. Genotyping for the 4G/5G PAI-1 gene was performed using Taqman assays in an ABI prism 7700 Sequencer several years after the pregnancy was completed. Pregnancy outcome data were extracted from the medical record. The primary outcome was a composite comprising development of severe pre-eclampsia, fetal growth restriction, major placental abruption, stillbirth or neonatal death. RESULTS: Pregnancy outcome data were available in 1733 women who were successfully genotyped for this polymorphism. The primary composite outcome was experienced by 139 women (8% of the cohort). Four hundred and fifty-nine women (26.5%) were homozygous for the 4G deletion polymorphism, while 890 (51.4%) were heterozygous. Neither homozygosity nor heterozygosity for the PAI-1 4G polymorphism was associated with the primary composite outcome (homozygous OR = 1.30, 95% CI = 0.81-2.09, P = 0.28, heterozygous OR = 0.84, 95% CI = 0.53-1.31, P = 0.44) or with the individual pregnancy complications. CONCLUSION: The PAI-1 4G polymorphism is not associated with an increase in the risk of serious adverse pregnancy events in asymptomatic nulliparous women.

Decorin expression is decreased in human idiopathic fetal growth restriction.

Fetal growth restriction (FGR) is a clinically significant pregnancy disorder in which the fetus fails to achieve its full growth potential in utero. Most cases of FGR are idiopathic and are associated with placental thrombosis. Previous studies suggest that proteoglycans, such as decorin, that contain the glycosaminoglycan dermatan sulfate are the principal anticoagulants in the normal placenta. The present study investigated decorin expression in placentas from pregnancies complicated by idiopathic FGR (n = 26) and gestation-matched controls (n = 27). Real-time polymerase chain reaction demonstrated significantly reduced decorin mRNA expression in FGR compared with control (1.52 +/- 0.14 v. 2.21 +/- 0.22, respectively; P < 0.01). Immunoblotting revealed decreased decorin protein (40 kDa) expression in FGR compared with controls (420.8 +/- 39.0 v. 690.1 +/- 42.2, respectively; n = 12 in each group; P = 0.0007). Immunohistochemistry demonstrated the presence of immunoreactive decorin protein in the placental villous stroma surrounding the fetal capillaries and a significant decrease in decorin protein presence in FGR compared with control (1.75 +/- 0.66 v. 2.98 +/- 1.12, respectively; n = 6 in each group; P < 0.01, t-test). This is the first study to demonstrate reduced decorin in idiopathic FGR, indicating a potentially significant role for decorin in the aetiology of placental thrombosis in idiopathic FGR.

Placental biglycan expression is decreased in human idiopathic fetal growth restriction.

Fetal growth restriction (FGR) is a leading cause of perinatal morbidity and mortality. The majority of FGR cases are idiopathic and are associated with placental insufficiency, which can result from placental thrombosis. Evidence suggests that Dermatan Sulfate (DS) is an important anti-coagulant in placentae of uncomplicated pregnancies. This study hypothesised that the expression of biglycan proteoglycan, a source of DS, is decreased in idiopathic FGR placentae compared with placentae from uncomplicated pregnancies. This study aimed to determine biglycan mRNA, protein expression and spatial distribution in idiopathic FGR placentae compared with the placentae from gestation-matched controls. Biglycan mRNA expression, protein expression and spatial distribution was determined in 26 idiopathic FGR-affected placentae and 27 placentae from gestation-matched controls (27-40 weeks gestation) using real-time PCR, immunoblotting and immunohistochemistry, respectively. Mean biglycan mRNA expression was significantly decreased in FGR placentae compared with control placentae (2.87 +/- 0.55, (n = 26) vs. 4.48 +/- 0.85, (n = 27); t-test p = 0.01). FGR placentae demonstrated a trend towards decrease in mean biglycan protein expression compared with control placentae (0.86 +/- 0.22 (n = 9, FGR) vs, 1.9 +/- 0.56 (n = 7, control) p = 0.07). Biglycan immunoreactivity was detected in endothelial cells and sub-endothelial cells of the perivascular region of fetal capillaries. Semi-quantitative analyses demonstrated a significant decrease in immunoreactive biglycan in FGR placentae compared with control placentae (51.1 +/- 19.3 vs, 500.7 +/- 223, n = 6, p < 0.001). This is the first study to demonstrate decreased biglycan expression in idiopathic FGR placentae compared to gestation-matched controls. Reduced biglycan expression may contribute to placental thrombosis within the fetal vasculature, and may contribute to the pathogenesis of idiopathic FGR.

Correlation of thromboelastography with standard tests of anticoagulation in paediatric patients receiving extracorporeal life support.

UNLABELLED: Children requiring extracorporeal life support (ECLS) are at significant risk for thrombotic and haemorrhagic complications. Thromboelastography (TEG) is increasingly being used to assist in monitoring the coagulation status of critically ill patients. Its role in heparinised children receiving ECLS is unknown. METHODS: A retrospective review of TEG in 27 children (mean age 2 years and 8 months) receiving ECLS in a tertiary paediatric intensive care unit between December 2006 and April 2008. Paired TEG (kaolin and heparinase) analysis was performed on 171 occasions. On all occasions activated partial thromboplastin time (APTT) and platelet count were performed within 4 hours of the TEG (mean 6.5 minutes after TEG). On 158 occasions, the activated clotting time (ACT) was measured simultaneously with TEG. RESULTS: The TEG (kaolin) sample was not interpretable due to the heparin effect in 89 (52%) samples. There was a weak correlation between TEG (heparinase) variables and APTT, and between TEG and ACT with a stronger correlation between TEG (Maximum amplitude) and platelet count. CONCLUSION: TEG monitoring should always include paired samples in heparinised children on ECLS. In this heterogeneous population, weak, and moderate correlations exist between TEG and standard haematological tests. Prospective studies, with simultaneous sampling for TEG and conventional laboratory tests, must be performed in order to establish its absolute utility as a clinical tool in this population.

Infantile megaloblastosis secondary to maternal vitamin B12 deficiency.

We reviewed six cases of infantile megaloblastosis secondary to maternal vitamin B12 deficiency, the most common cause of infantile megaloblastosis in our institution. Two patients had long-term neurological sequelae, with a further patient remaining abnormal but at short follow-up. In 50% of cases the mother was asymptomatic, with subtle or no peripheral blood abnormalities, having early pernicious anaemia. Any infant which fails to thrive, with progressive neurological deterioration and haematological cytopenias should have their vitamin B12 and folate status rapidly assessed. This is one of the few potentially reversible causes of failure to thrive and neurological deterioration. Early diagnosis and treatment may prevent significant long-term sequelae.

Long-term follow up of patients with transcobalamin II deficiency.

Five cases of transcobalamin II deficiency presenting to our institution were reviewed. A delay in diagnosis often led to acute deterioration. Two patients have long term neurological sequelae. Minimal treatment in these patients may be dangerous. While haematological normality may be maintained, the adequate therapeutic dose of vitamin B-12 to allow normal neurological development and function is not easily determined and damage sustained early in life may be irreversible.