14,15-Dihydroxyeicosatrienoic acid, a soluble epoxide hydrolase metabolite in blood, is a predictor of anthracycline-induced cardiotoxicity - a hypothesis generating study.

Background: Early identification of patients susceptible to chemotherapy-induced cardiotoxicity could lead to targeted treatment to reduce cardiac dysfunction. Rats treated with doxorubicin (DOX), a chemotherapeutic agent, have increased cardiac expression of 14,15-dihydroxyeicosatrienoic acid (14,15-DHET), a bioactive lipid implicated in hypertension and coronary artery disease. However, the utility of 14,15-DHET as plasma biomarkers was not defined.

Levels of plasma glycan-binding auto-IgG biomarkers improve the accuracy of prostate cancer diagnosis.

Strategies to improve the early diagnosis of prostate cancer will provide opportunities for earlier intervention. The blood-based prostate-specific antigen (PSA) assay is widely used for prostate cancer diagnosis but specificity of the assay is not satisfactory. An algorithm based on serum levels of PSA combined with other serum biomarkers may significantly improve prostate cancer diagnosis.

The role of soluble epoxide hydrolase in preeclampsia.

Preeclampsia is a serious complication of pregnancy characterized by the development of vasospasm, hypertension and often associated with proteinuria after the 20th week of gestation. Because termination of pregnancy results in the most efficacious resolution of preeclampsia, it is a leading cause of premature delivery worldwide. In pregnancy, 14,15-epoxyeicosatrienoic acids (EETs) have been shown to facilitate uterine blood flow during preeclampsia, in which the classic vasodilator agents such as nitric oxide and prostacyclin are reduced.

Differential BPA levels in sewage wastewater effluents from metro Detroit communities.

The endocrine disruptor Bisphenol A (BPA) is ubiquitous in both aquatic and surface sediment environments because it is continuously released into sewage wastewater effluent. The measurement of BPA at wastewater treatment plants is rarely performed even though the United States Environmental Protection Agency (EPA) states that current levels of environmental BPA could be a threat to aquatic organisms. Therefore, the aims of this study were to measure BPA levels in sewage wastewater at different collection points over a 1-year period and to compare the levels of BPA to 8-isoprostane, a human derived fatty acid, found in sewage wastewater.

The link between hypothalamic epigenetic modifications and long-term feeding control.

The incidence of obesity, one of the main risks for type 2 diabetes and cardiovascular disease, has been rising, and changes in eating behavior are associated with this increasing rate. Body weight is maintained via a complex integration of endocrine and neuronal inputs that regulate the control of orexigenic and anorexigenic neuropeptides in the arcuate nucleus of the hypothalamus. Overfeeding may disrupt the mechanisms of feeding control, increasing orexigenic peptides such as neuropeptide Y (NPY), and/or decreasing the anorexigenic peptide proopiomelanocortin (POMC) leading to a change in energy balance and body-weight index.

The effect of physical exercise on orexigenic and anorexigenic peptides and its role on long-term feeding control.

Over the past decades, life-styles changing have led to exacerbated food and caloric intake and a reduction in energy expenditure. Obesity, main outcome of these changes, increases the risk for developing type 2 diabetes, cardiovascular disease and metabolic syndrome, the leading cause of death in adult and middle age population. Body weight and energy homeostasis are maintained via complex interactions between orexigenic and anorexigenic neuropeptides that take place predominantly in the hypothalamus.

Glutathione Levels and Susceptibility to Chemically Induced Injury in Two Human Prostate Cancer Cell Lines.

More aggressive prostate cancer cells (PCCs) are often resistant to chemotherapy. Differences exist in redox status and mitochondrial metabolism that may help explain this phenomenon. Two human PCC lines, PC-3 cells (more aggressive) and LNCaP cells (less aggressive), were compared with regard to cellular glutathione (GSH) levels, susceptibility to either oxidants or GSH depletors, and expression of several proteins involved in apoptosis and stress response to test the hypothesis that more aggressive PCCs exhibit higher GSH concentrations and are relatively resistant to cytotoxicity.

Multigenerational study of chemically induced cytotoxicity and proliferation in cultures of human proximal tubular cells.

Primary cultures of human proximal tubular (hPT) cells are a useful experimental model to study transport, metabolism, cytotoxicity, and effects on gene expression of a diverse array of drugs and environmental chemicals because they are derived directly from the in vivo human kidney. To extend the model to investigate longer-term processes, primary cultures (P0) were passaged for up to four generations (P1-P4). hPT cells retained epithelial morphology and stained positively for cytokeratins through P4, although cell growth and proliferation successively slowed with each passage.

Adaptive changes in renal mitochondrial redox status in diabetic nephropathy.

Nephropathy is a serious and common complication of diabetes. In the streptozotocin (STZ)-treated rat model of diabetes, nephropathy does not typically develop until 30 to 45days post-injection, although hyperglycemia occurs within 24h. We tested the hypothesis that chronic hyperglycemia results in a modest degree of oxidative stress that is accompanied by compensatory changes in certain antioxidants and mitochondrial redox status.

Effect of innate glutathione levels on activity of redox-responsive gene delivery vectors.

Redox-responsive polyplexes represent a promising class of non-viral gene delivery vectors. The reducible disulfide bonds in the polyplexes undergo intracellular reduction owing to the presence of high concentrations of reduced glutathione (GSH). Available evidence suggests improved transfection activity of redox-sensitive polyplexes upon artificial modulation of intracellular GSH.

Assessment of the renal toxicity of novel anti-inflammatory compounds using cynomolgus monkey and human kidney cells.

PF1, an anti-inflammatory drug candidate, was nephrotoxic in cynomolgus monkeys in a manner that was qualitatively comparable to that observed with the two previous exploratory drug candidates (PF2and PF3). Based on the severity of nephrotoxicity, PF1 ranked between the other two compounds, withPF2 inducing mortality at all doses and PF3 eliciting only mild nephrotoxicity. To further characterize nephrotoxicity in monkeys and enable direct comparisons with humans, primary cultures of proximal tubular (PT) cells from monkey and human kidneys were used as in vitro tools, using lactate dehydrogenase release as the biomarker of cytotoxicity.

Role of mitochondrial dysfunction in cellular responses to S-(1,2-dichlorovinyl)-L-cysteine in primary cultures of human proximal tubular cells.

The nephrotoxic metabolite of the environmental contaminant trichloroethylene, S-(1,2-dichlorovinyl)-l-cysteine (DCVC), is known to elicit cytotoxicity in rat and human proximal tubular (rPT and hPT, respectively) cells that involves inhibition of mitochondrial function. DCVC produces a range of cytotoxic and compensatory responses in hPT cells, depending on dose and exposure time, including necrosis, apoptosis, repair, and enhanced cell proliferation. The present study tested the hypothesis that induction of mitochondrial dysfunction is an obligatory step in the cytotoxicity caused by DCVC in primary cultures of hPT cells.

Overexpression of Bcl-2 as a proxy redox stimulus to enhance activity of non-viral redox-responsive delivery vectors.

Redox-sensitive non-viral delivery systems exploit intracellular reducing environment to improve the efficacy of the delivery of nucleic acids by selectively releasing the cargo in the subcellular space. Bcl-2 overexpression is frequently observed in human cancers and is closely associated with increased resistance to chemotherapy and radiotherapy. One of the biochemical alterations accompanying Bcl-2 overexpression is the increase in cellular glutathione (GSH) levels.

Hepatic mitochondrial transport of glutathione: studies in isolated rat liver mitochondria and H4IIE rat hepatoma cells.

Glutathione (GSH) is transported into renal mitochondria by the dicarboxylate (DIC; Slc25a10) and 2-oxoglutarate carriers (OGC; Slc25a11). To determine whether these carriers function similarly in liver mitochondria, we assessed the effect of competition with specific substrates or inhibitors on GSH uptake in isolated rat liver mitochondria. GSH uptake was uniphasic, independent of ATP hydrolysis, and exhibited K(m) and V(max) values of 4.

Drug metabolism enzyme expression and activity in primary cultures of human proximal tubular cells.

We previously catalogued expression and activity of organic anion and cation, amino acid, and peptide transporters in primary cultures of human proximal tubular (hPT) cells to establish them as a cellular model to study drug transport in the human kidney [Lash, L.H., Putt, D.

Role of rat organic anion transporter 3 (Oat3) in the renal basolateral transport of glutathione.

The tripeptide GSH is important in maintenance of renal redox status and defense against reactive electrophiles and oxidants. Previous studies showed that GSH is transported across the basolateral plasma membrane (BLM) into the renal proximal tubule by both sodium-coupled and sodium-independent pathways. Substrate specificity and inhibitor studies suggested the function of several carriers, including organic anion transporter 3 (Oat3).

Interactive toxicity of inorganic mercury and trichloroethylene in rat and human proximal tubules: effects on apoptosis, necrosis, and glutathione status.

Simultaneous or prior exposure to one chemical may alter the concurrent or subsequent response to another chemical, often in unexpected ways. This is particularly true when the two chemicals share common mechanisms of action. The present study uses the paradigm of prior exposure to study the interactive toxicity between inorganic mercury (Hg(2+)) and trichloroethylene (TRI) or its metabolite S-(1,2-dichlorovinyl)-l-cysteine (DCVC) in rat and human proximal tubule.

Modulation of hepatic and renal metabolism and toxicity of trichloroethylene and perchloroethylene by alterations in status of cytochrome P450 and glutathione.

The relative importance of metabolism of trichloroethylene (Tri) and perchloroethylene (Perc) by the cytochrome P450 (P450) and glutathione (GSH) conjugation pathways in their acute renal and hepatic toxicity was studied in isolated cells and microsomes from rat kidney and liver after various treatments to modulate P450 activity/expression or GSH status. Inhibitors of P450 stimulated GSH conjugation of Tri and, to a lesser extent, Perc, in both kidney cells and hepatocytes. Perc was a more potent, acute cytotoxic agent in isolated kidney cells than Tri but Perc-induced toxicity was less responsive than Tri-induced toxicity to modulation of P450 status.

Membrane transport function in primary cultures of human proximal tubular cells.

To further develop primary cultures of human proximal tubular (hPT) cells for study of drug disposition, we determined kinetics and protein expression of several key transporters for organic anions and cations, peptides, and neutral amino acids. p-Aminohippurate uptake exhibited similar kinetics as published values, was inhibited by cephaloridine, cimetidine, methotrexate, and urate, consistent with function of both organic anion transporter 1 (OAT1) and OAT3. Transport rates by organic cation transporters (OCTs) were up to three-fold higher than those of OATs.

Influence of compensatory renal growth on susceptibility of primary cultures of renal cells to chemically induced injury.

Primary cultures of rat renal proximal tubular (PT) and distal tubular (DT) cells from control and uninephrectomized (NPX) Sprague-Dawley rats were established to study whether the altered toxicological responses identified in freshly isolated cells are maintained in culture. Previous work showed that primary cultures of PT cells from hypertrophied rat kidneys maintained their differentiated properties, as evidenced by their high respiratory rate, active transport function, transport and metabolism of glutathione, and their hypertrophic phenotype. In the present study, primary cultures of PT cells from NPX rat kidneys, but to a much lesser extent DT cells, were more susceptible to cellular injury induced by either mercuric chloride, KCN, or tert-butyl hydroperoxide (tBH), than corresponding cells from normal rat kidneys.

Metabolism and tissue distribution of orally administered trichloroethylene in male and female rats: identification of glutathione- and cytochrome P-450-derived metabolites in liver, kidney, blood, and urine.

Male and female Fischer 344 rats were administered trichloroethylene (TRI) (2, 5, or 15 mmol/kg body weight) in corn oil by oral gavage, and TRI and its metabolites were measured at times up to 48 h in liver, kidneys, blood, and urine. Studies tested the hypothesis that gender-dependent differences in distribution and metabolism of TRI could help explain differences in toxicity. Higher levels of TRI were generally observed in tissues of males at lower doses.

Modulation of expression of rat mitochondrial 2-oxoglutarate carrier in NRK-52E cells alters mitochondrial transport and accumulation of glutathione and susceptibility to chemically induced apoptosis.

We previously showed that two anion carriers of the mitochondrial inner membrane, the dicarboxylate carrier (DIC; Slc25a10) and oxoglutarate carrier (OGC; Slc25a11), transport glutathione (GSH) from cytoplasm into mitochondrial matrix. In the previous study, NRK-52E cells, derived from normal rat kidney proximal tubules, were transfected with the wild-type cDNA for the DIC expressed in rat kidney; DIC transfectants exhibited increased mitochondrial uptake and accumulation of GSH and were markedly protected from chemically induced apoptosis. In the present study, cDNAs for both wild-type (WT) and a double-cysteine mutant of rat OGC (rOGC and rOGC-C221,224S, respectively) were expressed in Escherichia coli, purified, and reconstituted into proteoliposomes to assess their function.

Pulmonary bronchiolar cytotoxicity and formation of dichloroacetyl lysine protein adducts in mice treated with trichloroethylene.

This study was undertaken to test the hypothesis that bronchiolar damage induced by trichloroethylene (TCE) is associated with bioactivation within the Clara cells with the involvement of CYP2E1 and CYP2F2. Histopathology confirmed dose-dependent Clara cell injury and disintegration of the bronchiolar epithelium in CD-1 mice treated with TCE doses of 500 to 1000 mg/kg i.p.

Role of organic anion and amino acid carriers in transport of inorganic mercury in rat renal basolateral membrane vesicles: influence of compensatory renal growth.

Susceptibility to renal injury induced by inorganic mercury (Hg(2+)) increases significantly as a result of compensatory renal growth (following reductions of renal mass). We hypothesize that this phenomenon is related in part to increased basolateral uptake of Hg(2+) by proximal tubular cells. To determine the mechanistic roles of various transporters, we studied uptake of Hg(2+), in the form of biologically relevant Hg(2+)-thiol conjugates, using basolateral membrane (BLM) vesicles isolated from the kidney(s) of control and uninephrectomized (NPX) rats.

Pulmonary bioactivation of trichloroethylene to chloral hydrate: relative contributions of CYP2E1, CYP2F, and CYP2B1.

Pulmonary cytotoxicity induced by trichloroethylene (TCE) is associated with cytochrome P450-dependent bioactivation to reactive metabolites. In this investigation, studies were undertaken to test the hypothesis that TCE metabolism to chloral hydrate (CH) is mediated by cytochrome P450 enzymes, including CYP2E1, CYP2F, and CYP2B1. Recombinant rat CYP2E1 catalyzed TCE metabolism to CH with greater affinity than did the recombinant P450 enzymes, rat CYP2F4, mouse CYP2F2, rat CYP2B1, and human CYP2E1.