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- Author: Michael Permezel x
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Mercy Perinatal Research Centre, Translational Proteomics, Department of Obstetrics and Gynaecology
Mercy Perinatal Research Centre, Translational Proteomics, Department of Obstetrics and Gynaecology
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Mercy Perinatal Research Centre, Translational Proteomics, Department of Obstetrics and Gynaecology
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Mercy Perinatal Research Centre, Translational Proteomics, Department of Obstetrics and Gynaecology
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In response to oxidative stress, gestational diabetes mellitus (GDM) placenta releases less 8-isoprostane and tumour necrosis factor (TNF) α. The effect of oxidative stress on other cytokines and antioxidant gene expressions are unknown. The aim of this study is to further explore the antioxidant status and effect of oxidative stress in GDM tissue. Human placenta, omental and subcutaneous adipose tissue from women with and without GDM were exposed to hypoxanthine (HX)/xanthine oxidase (XO). Cytokine release was analysed by ELISA and cytokine and antioxidant gene expression by RT-PCR. Catalase (CAT) and glutathione reductase (GSR) mRNA expression was higher in GDM (n=18) compared with normal (n=23) placenta. There was no difference in glutathione peroxidase and superoxide dismutase mRNA expression. Antioxidant gene expression was unaltered between normal (n=18) and GDM (n=10) adipose tissue. HX/XO treatment significantly stimulated cytokine release (13/16 cytokines) and cytokine mRNA expression, and decreased antioxidant gene expression (CAT and GSR) in human placenta from normal pregnant women. In GDM placenta, HX/XO only significantly increased the release of 3/16 cytokines, while there was no effect on antioxidant gene expression. In normal and GDM adipose tissues, HX/XO increased proinflammatory cytokine and 8-isoprostane release, while there was no change in antioxidant gene expression. GDM placenta is characterised by increased antioxidant gene expression, and is less responsive to exogenous oxidative stress than tissues obtained from normal pregnant women. This may represent a protective or adaptive mechanism to prevent damage from further oxidative insult in utero as indicated by increased tissue antioxidant expression.
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Department of Obstetrics and Gynaecology, Mercy Perinatal Research Centre, Department of Medicine, Mercy Hospital for Women, University of Melbourne, Level 4/163 Studley Road, Heidelberg 3084, Victoria, Australia
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Department of Obstetrics and Gynaecology, Mercy Perinatal Research Centre, Department of Medicine, Mercy Hospital for Women, University of Melbourne, Level 4/163 Studley Road, Heidelberg 3084, Victoria, Australia
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Appropriate foetal growth and development is dependent on adequate placental glucose uptake. Oxidative stress regulates glucose uptake in various tissues. The effect of oxidative stress on placental glucose transport is not known. Thus, the aim of this study was to determine the effect of oxidative stress on glucose uptake and glucose transporters (GLUTs) in human placenta. Human placenta was incubated in the absence or presence of 0.5 mM hypoxanthine+15 mU/ml xanthine oxidase (HX/XO) for 24 h. Gene and protein expressions of the GLUTs were analysed by quantitative RT-PCR and western blotting respectively. Glucose uptake was measured using radiolabelled (14C) glucose. HX/XO significantly decreased GLUT1 gene and protein expression and resultant glucose uptake. There was no effect of the antioxidants N-acetylcysteine, catalase and superoxide dismutase or the NF-κB inhibitor BAY 11-0782 on HX/XO-induced decrease in glucose uptake. However, HX/XO treatment significantly decreased both gene and protein expression of SIRT1. In the presence of the SIRT1 activator resveratrol, the decrease in GLUT1 expression and glucose uptake mediated by HX/XO was abolished. Collectively, the data presented here demonstrate that oxidative stress reduces placental glucose uptake and GLUT1 expression by a SIRT1-dependent mechanism.
Translational Proteomics, Baker Medical Research Institute, Baker Heart Research Institute, Melbourne, Victoria 3004, Australia
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Translational Proteomics, Baker Medical Research Institute, Baker Heart Research Institute, Melbourne, Victoria 3004, Australia
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Translational Proteomics, Baker Medical Research Institute, Baker Heart Research Institute, Melbourne, Victoria 3004, Australia
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Processes of human labour include increased oxidative stress, formation of inflammatory mediators (e.g. cytokines) and uterotonic phospholipid metabolites (e.g. prostaglandins). In non-gestational tissues, advanced glycation endproducts (AGE) induce the expression of pro-inflammatory molecules through mitogen-activated protein kinase and nuclear factor κB (NF-κB)-dependent pathways. Thus, the aim of this study was to investigate the effects of AGE on 8-isoprostane (a marker of oxidative stress), pro-inflammatory cytokine and prostaglandin release in human gestational tissues, and to define the signalling pathways involved. Human placenta and gestational membranes (amnion and choriodecidua combined; n=5) were incubated in the absence or presence of AGE–BSA (0.25, 0.5, 1 and 2 mg/ml) for 18 h. AGE significantly increased in vitro release of tumour necrosis factor-α, interleukin (IL)-1β, IL-6, IL-8, prostaglandin (PG)E2, PGF2α and 8-isoprostane from human placenta and gestational membranes. This was associated with a concomitant increase in NF-κB p65 activation and ERK 1/2 phosphorylation. AGE-stimulated 8-isoprostane, cytokine and prostaglandin production was significantly suppressed by the ERK 1/2 inhibitor U0126 and the NF-κB inhibitor BAY 11-7082. In conclusion, AGE mediates inflammatory actions in human gestational tissues. Protein kinases and the NF-κB pathway play an essential role in AGE signalling in human gestational tissues.
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The aim of this study was to determine the release and regulation of leptin, resistin and adiponectin from human placenta and fetal membranes, and maternal subcutaneous adipose tissue and skeletal muscle obtained from normal and gestational diabetes mellitus (GDM)-complicated pregnancies at the time of Cesarean section. Tissue explants were incubated in the absence (basal control) or presence of 10 μg/ml lipopolysaccharide (LPS), 10, 20 or 40 ng/ml tumor necrosis factor-α (TNF-α), interleukin (IL)-6 and IL-8, 1 μM phorbol myristate acetate, 10, 20 and 40 mM glucose, 0.1, 1 and 10 μM insulin and 0.1 1 and 10 μM dexamethasone, progesterone and estrogen. After an 18-h incubation, the medium was collected and the release of leptin, resistin and adiponectin was quantified by ELISA. Human gestational tissues and maternal tissues released immunoreactive leptin, resistin and adiponectin; however, there was no difference in the release of either resistin or adiponectin between normal pregnant women and women with gestational diabetes. The release of leptin was significantly higher in placenta, amnion and choriodecidua obtained from normal pregnant women compared with women with GDM. However, in maternal tissues, the situation was reversed, with adipose tissue and skeletal muscle obtained from women with GDM releasing significantly greater amounts of leptin. In adipose tissue and skeletal muscle the release of leptin was significantly greater in insulin-controlled GDM compared with diet-controlled GDM, and leptin release from adipose tissue was significantly correlated with maternal body mass index. In all tissues tested, there was no effect of incubation with LPS, IL-6, IL-8 or TNF-α on leptin, resistin or adiponectin release. PMA significantly increased the release of resistin from placenta and adipose tissue. Insulin increased placental resistin release, whereas the hormones dexamethasone, progesterone and estrogen significantly decreased placental resistin release. The data presented in this study demonstrate that dysregulation of leptin metabolism and/or function in the placenta may be implicated in the pathogenesis of GDM. Furthermore, resistin release is greatly affected by a variety of inflammatory mediators and hormones.
