Showing papers by "Garth J. S. Cooper published in 2009"

A proteomic approach identifies early pregnancy biomarkers for preeclampsia: Novel linkages between a predisposition to preeclampsia and cardiovascular disease

Abstract: Preeclampsia (PE) is a common, potentially life-threatening pregnancy syndrome triggered by placental factors released into the maternal circulation, resulting in maternal vascular dysfunction along with activated inflammation and coagulation. Currently there is no screening test for PE. We sought to identify differentially expressed plasma proteins in women who subsequently develop PE that may perform as predictive biomarkers. In seven DIGE experiments, we compared the plasma proteome at 20 wk gestation in women who later developed PE with an appropriate birth weight for gestational age baby (n=27) or a small for gestational age baby (n=12) to healthy controls with uncomplicated pregnancies (n=57). Of the 49 differentially expressed spots associated with PE-appropriate for gestational age, PE-small for gestational age or both (p 90%) classified women at risk of developing PE were identified. Immunoblots confirmed the overexpression of fibrinogen gamma chain and alpha-1-antichymotrypsin in plasma prior to PE. The proteins identified are involved in lipid metabolism, coagulation, complement regulation, extracellular matrix remodeling, protease inhibitor activity and acute-phase responses, indicating novel synergism between pathways involved in the pathogenesis of PE. Our findings are remarkably similar to recently identified proteins complexed to high-density lipoprotein and linked to cardiovascular disease.

Adiponectin haploinsufficiency promotes mammary tumor development in MMTV-PyVT mice by modulation of phosphatase and tensin homolog activities

Abstract: Background Adiponectin is an adipokine possessing beneficial effects on obesity-related medical complications. A negative association of adiponectin levels with breast cancer development has been demonstrated. However, the precise role of adiponectin deficiency in mammary carcinogenesis remains elusive. Methodology/Principal Findings In the present study, MMTV-polyomavirus middle T antigen (MMTV-PyVT) transgenic mice with reduced adiponectin expressions were established and the stromal effects of adiponectin haploinsufficiency on mammary tumor development evaluated. In mice from both FVB/N and C57BL/6J backgrounds, insufficient adiponectin production promoted mammary tumor onset and development. A distinctive basal-like subtype of tumors, with a more aggressive phenotype, was derived from adiponectin haplodeficient MMTV-PyVT mice. Comparing with those from control MMTV-PyVT mice, the isolated mammary tumor cells showed enhanced tumor progression in re-implanted nude mice, accelerated proliferation in primary cultures, and hyperactivated phosphatidylinositol-3-kinase (PI3K)/Akt/beta-catenin signaling, which at least partly attributed to the decreased phosphatase and tensin homolog (PTEN) activities. Further analysis revealed that PTEN was inactivated by a redox-regulated mechanism. Increased association of PTEN-thioredoxin complexes was detected in tumors derived from mice with reduced adiponectin levels. The activities of thioredoxin (Trx1) and thioredoxin reductase (TrxR1) were significantly elevated, whereas treatment with either curcumin, an irreversible inhibitor of TrxR1, or adiponectin largely attenuated their activities and resulted in the re-activation of PTEN in these tumor cells. Moreover, adiponectin could inhibit TrxR1 promoter-mediated transcription and restore the mRNA expressions of TrxR1. Conclusion Adiponectin haploinsufficiency facilitated mammary tumorigenesis by down-regulation of PTEN activity and activation of PI3K/Akt signalling pathway through a mechanism involving Trx1/TrxR1 redox regulations.

A copper(II)-selective chelator ameliorates left-ventricular hypertrophy in type 2 diabetic patients: a randomised placebo-controlled study

Abstract: Aims/hypothesis Cu(II)-selective chelation with trientine ameliorates cardiovascular and renal disease in a model of diabetes in rats. Here, we tested the hypothesis that Cu(II)-selective chelation might improve left ventricular hypertrophy (LVH) in type 2 diabetic patients.

Proteins associated with immunopurified granules from a model pancreatic islet beta-cell system: proteomic snapshot of an endocrine secretory granule.

Abstract: beta-Cell granules contain proteins involved in fuel regulation, which when altered, contribute to metabolic disorders including diabetes mellitus. We analyzed proteins present in purified granules from the INS-1E beta-cell model. Fifty-one component proteins were identified by LC-MS/MS including hormones, granins, protein processing components, cellular trafficking components, enzymes implicated in cellular metabolism and chaperone proteins. These findings may increase understanding of granule secretion and the processes leading to protein aggregation and beta-cell death in type-2 diabetes.

The proteome of mesenteric lymph during acute pancreatitis and implications for treatment.

Abstract: Context The protein fraction of mesenteric lymph during acute pancreatitis and other critical illness is thought to contain toxic factors. However, we do not have a complete description of the mesenteric lymph proteome during acute pancreatitis. Objective The aim of this study was to define the proteomic changes in mesenteric lymph during acute pancreatitis. Setting Animal Laboratory, University of Auckland, New Zealand. Design Mesenteric lymph was collected from sixteen male Wistar rats randomised to Group 1 (n=8) with taurocholate induced acute pancreatitis and Group 2 (n=8) sham control. The lymph was subjected to proteomic analysis using iTRAQ TM (Applied Biosystems, Foster City, CA, USA) and liquid chromatography-tandem mass spectrometry. Results Two hundred and forty-five proteins including 35 hypothetical proteins were identified in mesenteric lymph. Eight of the 245 proteins had a significant increase in their relative abundance in acute pancreatitis conditioned mesenteric lymph, and 7 of these were pancreatic catabolic enzymes (pancreatic amylase 2, pancreatic lipase, carboxypeptidase A2, chymotrypsinogen B, carboxypeptidase B1, cationic trypsinogen, ribonuclease 1). Conclusions This is the first comprehensive description of the proteome of mesenteric lymph during acute pancreatitis and has demonstrated a significantly increased relative abundance of 7 secreted pancreatic catabolic enzymes in acute pancreatitis conditioned mesenteric lymph. This study provides a clear rationale for further research to investigate the efficacy of enteral protease inhibitors in the treatment of acute pancreatitis.

Quantitative proteomic profiling identifies new renal targets of copper(II)-selective chelation in the reversal of diabetic nephropathy in rats.

Abstract: This study aimed to identify new diabetic nephropathy (DN)-related proteins and renal targets of the copper(II)-selective chelator, triethylenetetramine (TETA) in streptozotocin-diabetic rats We used the recently developed iTRAQ technology to compare renal protein profiles among non-diabetic, diabetic, and TETA-treated diabetic rats In diabetic kidneys, tubulointerstitial nephritis antigen (TINag), voltage-dependent anion-selective channel (VDAC) 1, and VDAC2 were up-regulated in parallel with alterations in expression of proteins with functions in oxidative stress and oxidative phosphorylation (OxPhos) pathways By contrast, mitochondrial HSP 60, Cu/Zn-superoxide dismutase, glutathione S-transferase alpha3 and aquaporin-1 were down-regulated in diabetic kidneys Following TETA treatment, levels of D-amino acid oxidase-1, epoxide hydrolase-1, aquaporin-1, and a number of mitochondrial proteins were normalized, with concomitant amelioration of albuminuria Changes in levels of TINag, collagen VIalpha1, actinin 4alpha, apoptosis-inducing factor 1, cytochrome C, histone H3, VDAC1, and aquaporin-1 were confirmed by Western blotting or immunohistochemistry Changes in expression of proteins related to tubulointerstitial function, podocyte structure, and mitochondrial apoptosis are implicated in the mechanism of DN and their reversal by TETA These findings are consistent with the hypothesis that this new experimental therapy may be useful for treatment of DN

Impaired ATP turnover and ADP supply depress cardiac mitochondrial respiration and elevate superoxide in nonfailing spontaneously hypertensive rat hearts

Abstract: Although most attention has been focused on mitochondrial ATP production and transfer in failing hearts, less has been focused on the nonfailing hypertensive heart. Here, energetic complications are less obvious, yet they may provide insight into disease ontogeny. We studied hearts from 12-mo-old spontaneously hypertensive rats (SHR) relative to normotensive Wistar-Kyoto (WKY) rats. The ex vivo working-heart model of SHR showed reduced compliance and impaired responses to increasing preloads. High-resolution respirometry showed higher state 3 (with excess ADP) respiration in SHR left ventricle fibers with complex I substrates and maximal uncoupled respiration with complex I + complex II substrates. Respiration with ATP was depressed 15% in SHR fibers relative to WKY fibers, suggesting impaired ATP hydrolysis. This finding was consistent with a 50% depression of actomyosin ATPase activities. Superoxide production from SHR fibers was similar to that from WKY fibers respiring with ADP; however, it was increased by 15% with ATP. In addition, the apparent K(m) for ADP was 54% higher for SHR fibers, and assays conducted after ex vivo work showed a 28% depression of complex I in SHR, but not WKY, fibers. Transmission electron microscopy showed similar mitochondrial volumes but a decrease in the number of cristae in SHR mitochondria. Tissue lipid peroxidation was also 15% greater in SHR left ventricle. Overall, these data suggest that although cardiac mitochondria from nonfailing SHR hearts function marginally better than those from WKY hearts, they show dysfunction after intense work. Impaired ATP turnover in hard-working SHR hearts may starve cardiac mitochondria of ADP and elevate superoxide.

Pharmacokinetic and pharmacodynamic modeling of a copper-selective chelator (TETA) in healthy adults.

Abstract: The population pharmacokinetics (PK) and pharmacodynamics (PD) of triethylenetetramine (TETA) dihydrochloride (trientine, GC811007) administered orally as 100-, 300-, 600-, or 1800-mg twice-daily doses were assessed in healthy adult male and female volunteers. This study was a randomized, double-blind, placebo-controlled, group-sequential, dose-escalating design. Forty participants, 10 per dose level (8 receiving TETA, 2 receiving placebo), received twice-daily doses for 14 consecutive days. A 2-compartment model for the PK and a linear direct effect model for drug-induced copper excretion (PD) were employed. The population PK/PD model was applied using the NONMEM software. Covariates tested were glomerular filtration rate (GFR), body weight, and gender. Multiple daily doses of TETA were safe and generally well tolerated. The linear 2-compartment model with first-order absorption well characterized the serum concentration data. Although its role was small, GFR had a statistically significant (P < .05) influence on systemic clearance (CL/F). The augmentation of copper excretion was well described by a direct linear model in which the slope was related to GFR and gender (P < .001). The intersubject coefficient of variation was 22.2% for slope (SL) and 82.5% for intercept (ER0). TETA has consistent single/multiple-dose pharmacokinetics and dose-proportional and serum concentration-proportional effects on enhancing copper excretion.

Biomarkers for prediction of preeclampsia and/or cardiovascular disease

Abstract: Biomarkers and methods for use in predicting the risk of women developing preeclampsia and/or cardiovascular disease are described.

The redox status of experimental hemorrhagic shock as measured by cyclic voltammetry

Abstract: Hemorrhagic shock (HS) leads to reactive oxygen species production. However, clinicians do not have access to bedside measurements of the redox status during HS. Cyclic voltammetry (CyV) is a simple electrochemical method of measuring redox status. The aims of this study were to 1) report the first application of cyclic voltammetry to measure the acute changes in serum redox status after HS, 2) to contrast it with another severe systemic disease with a different redox pathology (acute pancreatitis [AP]), and 3) to describe the response of CyV over time in a resolving model of AP. In the acute study, 24 male Wistar rats were randomized into three groups: groups 1 (control), 2 (AP), and 3 (HS). In the time-course study, 28 rats were randomized to a sham-control as well as 6 and 24 h post-AP cohorts, respectively.Cyclic voltammetry was performed using a three-electrode system. In the acute study, the first and second voltammetric peaks increased significantly in HS. In contrast, within the AP group, only the first voltammetric peak showed a significant increase. The first voltammetric peak correlated with plasma protein carbonyls (PCs) and with thiobarbituric acid-reactive substances, whereas the second voltammetric peak correlated positively with plasma protein carbonyls. In the second study, the first voltammetric peak correlated with physiological improvements. Here, we showed that serum CyV could respond to the serum redox change in HS and AP. Cyclic voltammetry warrants evaluation as a potential real-time beside measure of a patient's redox status during shock.

Aberrant processing of plasma vitronectin and high-molecular-weight kininogen precedes the onset of preeclampsia.

Abstract: To date, there is no reliable test to identify women in early pregnancy at risk of developing preeclampsia. Difference gel electrophoresis (DIGE) identified the plasma proteins vitronectin (VN) and high-molecular-weight kininogen (HK) in association with preeclampsia. In a longitudinal proteomics study, the plasma of preeclamptic patients (n = 6) was compared to healthy control participants (n = 6) before the onset of preeclampsia (week 20) and at the time of presentation with clinical disease (weeks 33-36). The 75-kd single-chain VN molecule increased 1.6- to 1.9-fold in preeclampsia, whereas the 65-kd moiety of the 2-chain VN molecule decreased 1.5- to 1.7-fold compared to healthy controls (P < .05). Immunoblots revealed differences in proteolytic processing of VN and/or HK in women who develop preeclampsia or preeclampsia further complicated by small-for-gestational-age. Vitronectin and HK may prove to be useful as early markers of fibrinolytic activity and neutrophil activation, which are known to be associated with preeclampsia.