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M. W. Anders - One of the best experts on this subject based on the ideXlab platform.

  • Perturbation of maleylacetoacetic Acid metabolism in rats with Dichloroacetic Acid-induced glutathione transferase zeta deficiency
    Toxicological Sciences, 2003
    Co-Authors: Hoffman B. M. Lantum, Judith Cornejo, Robert H. Pierce, M. W. Anders
    Abstract:

    Glutathione transferase zeta (GSTZ1-1) catalyzes the isomerization of maleylacetoacetate (MAA) to fumarylacetoacetate, the penultimate step in the tyrosine degradation pathway. GSTZ1-1 is inactivated by Dichloroacetic Acid (DCA), which is used for the clinical management of congenital lactic Acidosis and is a drinking-water contaminant. Metabolic changes associated with chemically induced GSTZ1-1 deficiency are poorly understood. The objective of this study was to investigate the biochemical and toxicological effects of giving 0.3-1.2 mmol DCA/kg/day for 5 days on MAA-metabolism in male Fischer rats. Urine from DCA-treated rats inhibited delta-aminolevulinic Acid dehydratase (delta-ALAD) activity, which is used for the diagnosis of hereditary tyrosinemia type I. Mass spectrometric analyses of urine from rats given DCA demonstrated elevated excretion of MAA and its decarboxylation product, maleylacetone (MA); succinylacetone (SA), the reduced analogue of MA, was not detected. DCA-induced changes in MA excretion were dose-dependent and were significantly elevated after day 2 of treatment. MA excretion was reversible after discontinuation of DCA treatment and was enhanced 10-fold by the coadministration of homogentisic Acid (HGA). MA was cytotoxic to hepatocytes in vitro (EC50 ~ 350 microM) but morphological changes were not observed in liver, kidney, and brain of rats given both DCA and HGA. These data indicate that DCA-induced inactivation of GSTZ1-1 leads to formation of an MAA-derived intermediate, MA, that may be a mediator and biomarker for DCA-associated toxicities.

  • mass spectral characterization of Dichloroacetic Acid modified human glutathione transferase zeta
    Chemical Research in Toxicology, 2002
    Co-Authors: Wayne B Anderson, Philip G. Board, Daniel C Liebler, M. W. Anders
    Abstract:

    Glutathione transferase zeta (GSTZ1-1) is widely expressed in eukaryotic species, and four human allelic variants of hGSTZ1-1 have been described. GSTZ1-1 catalyzes the cis-trans isomerization of maleylacetoacetate to fumarylacetoacetate and the biotransformation of a range of alpha-haloalkanoic Acids. GSTZ1-1-catalyzed biotransformation of fluorine-lacking alpha,alpha-dihaloalkanoic Acids, including Dichloroacetic Acid (DCA), results in the mechanism-based inactivation and covalent modification of the enzyme. The objective of this study was to investigate further the DCA-induced inactivation of hGSTZ1c-1c and to explore the mechanism of inactivation by characterization of the sites and types of DCA-induced covalent modifications. The partition ratio for the DCA-induced, mechanism-based inactivation of hGSTZ1c-1c was (5.7 +/- 0.5) x 10(2), and the k(cat) for the biotransformation of DCA was 39 min(-)(1). Inactivation of hGSTZ1c-1c in vitro was limited at high enzyme concentrations and was inhibited by glyoxylate. The stoichiometry of DCA binding to hGSTZ1c-1c was approximately 0.5 mol of DCA/mol of enzyme monomer. A single DCA-derived adduct was observed and was assigned to cysteine-16 by a combination of matrix-assisted laser-desorption-ionization time-of-flight and electrospray-ionization quadrupole ion-trap mass spectrometry and by analysis of [1-(14)C]DCA binding to C16A hGSTZ1c-1c. The DCA-derived adduct contained both glutathione and the carbon skeleton of DCA, presumably in a dithioacetal linkage. Also, cysteine-16 formed a mixed disulfide bond with glutathione. These data support a mechanism of inactivation whereby glutathione displaces a chlorine atom from DCA, and cysteine-16 in the enzyme active site displaces the second chlorine atom to result in a covalently modified and inactivated enzyme. These findings explain the DCA-induced inactivation of GSTZ1-1 observed in humans and rats.

  • inactivation of glutathione transferase zeta by Dichloroacetic Acid and other fluorine lacking alpha haloalkanoic Acids
    Chemical Research in Toxicology, 1999
    Co-Authors: Warwick P Anderson, Philip G. Board, Bryan Gargano, M. W. Anders
    Abstract:

    Dichloroacetic Acid (DCA) is a contaminant of chlorinated drinking water supplies, is carcinogenic in rats and mice, and is a therapeutic agent used for the treatment of congenital lactic Acidosis. The biotransformation of DCA to glyoxylic Acid is catalyzed by glutathione transferase zeta (GSTZ). Treatment of rats and human subjects with DCA increases its plasma elimination half-life and reduces the extent of DCA biotransformation in rat hepatic cytosol. In the investigation presented here, the kinetics of the DCA-induced inactivation of GSTZ, the turnover of GSTZ, and the susceptibility of GSTZ to inactivation by a panel of α-haloAcids were studied. DCA rapidly inactivated GSTZ in both rat hepatic cytosol and intact Fischer 344 rats. The time course of inactivation in vivo was mirrored by a concomitant loss of immunoreactive GSTZ protein. The turnover of GSTZ in rat liver was 0.21 day-1, which corresponded to a half-life of 3.3 days. The degree of GSTZ inactivation after daily administration of DCA could...

  • glutathione transferase zeta catalyzed biotransformation of Dichloroacetic Acid and other alpha haloAcids
    Chemical Research in Toxicology, 1998
    Co-Authors: Zeen Tong, Philip G. Board, M. W. Anders
    Abstract:

    Dichloroacetic Acid (DCA) is a common drinking-water contaminant, is hepatocarcinogenic in rats and mice, and is a therapeutic agent used clinically in the management of lactic Acidosis. Recent studies show that glutathione transferase Zeta (GSTZ) catalyzes the oxygenation of DCA to glyoxylic Acid [Tong et al. (1998) Biochem. J. 331, 371-374]. In the present studies, the substrate selectivity of GSTZ, the kinetics of DCA metabolism, and the fate of DCA and glutathione were investigated. The results showed that GSTZ catalyzed the oxygenation of bromochloro-, bromofluoro-, chlorofluoro-, dibromo-, and Dichloroacetic Acid, but not difluoroacetic Acid, to glyoxylic Acid. GSTZ also catalyzed the biotransformation of fluoroacetic Acid to S-(carboxymethyl)glutathione, and of (R,S)-2-bromopropionic Acid, (R)-, (S)-, and (R,S)-2-chloropropionic Acid, and (R, S)-2-iodopropionic Acid, but not (R,S)-2-fluoropropionic Acid, to S-(alpha-methylcarboxymethyl)glutathione; and of 2, 2-dichloropropionic Acid to pyruvate. No biotransformation of 3, 3-dichloropropionic Acid was detected, and no GSTZ-catalyzed fluoride release from ethyl fluoroacetate and fluoroacetamide was observed. The relative rates of DCA biotransformation by hepatic cytosol were mouse > rat > human. Immunoblotting showed the presence of GSTZ in mouse, rat, and human liver cytosol. 13C NMR spectroscopic studies showed that [2-13C]glyoxylic Acid was the only observable, stable metabolite of [2-13C]DCA. Also, glutathione was required, but was neither consumed nor oxidized to glutathione disulfide, during the oxygenation of DCA to glyoxylic Acid. These results are consistent with a reaction mechanism that involves displacement of chloride from DCA by glutathione to afford S-(alpha-chlorocarboxymethyl)glutathione, which may undergo hydrolysis to give the hemithioacetal S-(alpha-hydroxycarboxymethyl)glutathione. Elimination of glutathione from the hemithioacetal would give glyoxylic Acid.

  • glutathione transferase zeta catalyses the oxygenation of the carcinogen Dichloroacetic Acid to glyoxylic Acid
    Biochemical Journal, 1998
    Co-Authors: Zeen Tong, Philip G. Board, M. W. Anders
    Abstract:

    Dichloroacetic Acid (DCA), a common drinking-water contaminant, is hepatocarcinogenic in rats and mice, and is a therapeutic agent used clinically in the management of lactic Acidosis. DCA is biotransformed to glyoxylic Acid by glutathione-dependent cytosolic enzymes in vitro and is metabolized to glyoxylic Acid in vivo. The enzymes that catalyse the oxygenation of DCA to glyoxylic Acid have not, however, been identified or characterized. In the present investigation, an enzyme that catalyses the glutathione-dependent oxygenation of DCA was purified to homogeneity (587-fold) from rat liver cytosol. SDS/PAGE and HPLC gel-filtration chromatography showed that the purified enzyme had a molecular mass of 27-28 kDa. Sequence analysis showed that the N-terminus of the purified protein was blocked. An internal sequence of 30 amino Acid residues was obtained that matched the recently discovered human glutathione transferase Zeta well [Board, Baker, Chelvanayagam and Jermiin (1997) Biochem. J. 328, 929-935]. Western-blot analysis showed that the purified rat-liver enzyme cross-reacted with rabbit antiserum raised against recombinant human glutathione transferase Zeta. The apparent Km and Vmax values of the purified enzyme with DCA as the variable substrate were 71.4 microM and 1334 nmol/min per mg of protein, respectively; the Km for glutathione was 59 microM. Both the purified rat-liver enzyme and the recombinant human enzyme showed high activity with DCA as the substrate. These results demonstrate that the glutathione-dependent oxygenation of DCA to glyoxylic Acid is catalysed by a Zeta-class glutathione transferase.

De Ab Andre Haan - One of the best experts on this subject based on the ideXlab platform.

Alex A Londono - One of the best experts on this subject based on the ideXlab platform.

  • isobaric low pressure vapor liquid equilibrium data of the system monochloroacetic Acid Dichloroacetic Acid diethylene glycol dipentyl ether and the constituent binary systems
    Fluid Phase Equilibria, 2012
    Co-Authors: Mtg Mark Jongmans, Boelo Schuur, Alex A Londono, De Ab Andre Haan
    Abstract:

    In this study, binary and ternary VLE data have been determined at 5, 7.5, and 10 kPa for the system monochloracetic Acid (MCA) + Dichloroacetic Acid (DCA) + diethylene glycol dipentyl ether (DGDP). The extractant DGDP enhances the relative volatility of the MCA/DCA system from 1.2 without extractant up to 4. The non-ideal behavior in the liquid and vapor phase was reasonably well correlated with the NRTL and Hayden–O’Connell (HOC) model, respectively. The binary and ternary VLE data were correlated separately to obtain a better description of both datasets

  • extractant screening for the separation of Dichloroacetic Acid from monochloroacetic Acid by extractive distillation
    Separation and Purification Technology, 2012
    Co-Authors: Mark Jongmans, Alex A Londono, S B Mamilla, H J Pragt, K T J Aaldering, Gerrald Bargeman, Melle Rinze Nieuwhof, Ten A Kate, Paul Verwer, Anton A Kiss
    Abstract:

    Monochloroacetic Acid (MCA) is produced via the chlorination of acetic Acid, in which a part is overchlorinated to the undesired Dichloroacetic Acid (DCA). The separation of DCA from MCA by distillation is highly energy intensive, because of the rather low relative volatility of ∼1.05–1.3, depending on the mixture composition. Extractive distillation is a promising alternative and often applied to separate close boiling mixtures. The benchmark solvent sulfolane is known to increase the relative volatility of the MCA/DCA mixture only slightly. By applying basic complexing agents, the large difference in the Acid dissociation constant between MCA (pKa = 2.87) and DCA (pKa = 1.25) can be exploited to further enhance the relative volatility of the MCA/DCA mixture. The aim of this study was to select a proper complexing agent. Such a complexing agent should not only enhance the relative volatility more than obtained with sulfolane, but also be stable in the presence of MCA and DCA, and the complexation should be reversible. To study on the relative volatility and the reversibility of complexation, vapor–liquid equilibrium (VLE) and thermal/chemical stability experiments were performed. Many extractants were found that improve the relative volatility more than sulfolane, with relative volatilities up to 5.9. There is, however, a clear trade-off between the effect of the extractant on the relative volatility of the MCA/DCA mixture and the regeneration ability of the extractant. Extractants with a strong effect on the relative volatility of the MCA/DCA mixture appeared difficult to regenerate. Complexation agents from the classes of ethers, ketones, and phosphine oxides, and the benchmark extractant sulfolane were the only extractants that demonstrated to be thermally/chemically stable in the strongly Acidic environment. With regard to the relative volatility, the regeneration ability, and the stability of the extractants, it was concluded that glymes, e.g. diethylene glycol dipentyl ether are the most promising extractants, improving the relative volatility of the MCA/DCA system up to 2.1–2.4 at a DCA/extractant molar ratio of 1.

  • isobaric low pressure vapor liquid equilibrium data for the binary system monochloroacetic Acid Dichloroacetic Acid
    Fluid Phase Equilibria, 2012
    Co-Authors: Alex A Londono, Boelo Schuur, Mtg Mark Jongmans, De Ab Andre Haan
    Abstract:

    Isobaric vapor–liquid equilibrium (VLE) data for the binary system monochloroacetic Acid + Dichloroacetic Acid have been measured at 5, 7.5, and 10 kPa. The VLE data measured in this work is thermodynamically consistent according to the Herington area method. The non-ideal behavior in the vapor phase was correlated using the Hayden–O’Connell model. Wilson, NRTL, and UNIQUAC were used to account for the liquid phase non-idealities. All activity coefficient models were able to describe the experimental VLE data very well. Wilson and UNIQUAC described the VLE data slightly better than NRTL. The correlated equilibrium temperatures and vapor phase compositions were in all cases in good agreement with the experimental data.

Philip G. Board - One of the best experts on this subject based on the ideXlab platform.

  • Dichloroacetic Acid up-regulates hepatic glutathione synthesis via the induction of glutamate-cysteine ligase
    Biochemical Pharmacology, 2011
    Co-Authors: Angelo Theodoratos, Jane E. Dahlstrom, Anneke C. Blackburn, Jean Cappello, Padmaja Tummala, Philip G. Board
    Abstract:

    Abstract Dichloroacetic Acid (DCA) has potential for use in cancer therapy and the treatment of metabolic Acidosis. However, DCA can create a deficiency of glutathione transferase Zeta (GSTZ1-1). Gstz1 knockout mice have elevated oxidative stress and low glutathione levels that increases their sensitivity to acetaminophen toxicity. As it is highly likely that patients that are treated with DCA will develop drug induced GSTZ1-1 deficiency we considered they could be at risk of elevated toxicity if they are exposed to other drugs that cause oxidative stress or consume glutathione (GSH). To test this hypothesis we treated mice with DCA and acetaminophen (APAP). Surprisingly, the mice pre-treated with DCA suffered less APAP-mediated hepatotoxicity than untreated mice. This protection is most likely due to an increased capacity for the liver to synthesize GSH, since DCA increased the expression and activity of glutamate–cysteine ligase GCL, the rate-limiting enzyme of GSH synthesis. Other pathways for acetaminophen disposal were unchanged or diminished by DCA. Pre-treatment with DCA may be of use in other settings where the maintenance of protective levels of GSH are required. However, DCA may lower the efficacy of drugs that rely on oxidative stress and the depletion of GSH to enhance their cytotoxicity or of drugs that are detoxified by GSH conjugation. Consequently, as the use of DCA in the clinic is likely to increase, it will be critical to evaluate the interactions of DCA with other drugs to ensure the combinations retain their efficacy and do not cause enhanced toxicity.

  • phenylalanine induced leucopenia in genetic and Dichloroacetic Acid generated deficiency of glutathione transferase zeta
    Biochemical Pharmacology, 2009
    Co-Authors: Angelo Theodoratos, Anneke C. Blackburn, Jean Cappello, Klaus I Matthaei, Philip G. Board
    Abstract:

    Glutathione transferase Zeta (GSTZ1-1) is identical to maleylacetoacetate isomerase and catalyses a significant step in the catabolism of phenylalanine and tyrosine. Exposure of GSTZ1-1 deficient mice to high dietary phenylalanine causes a rapid loss of circulating white blood cells (WBCs). The loss was significant (P<0.05) after 2 days and total WBCs were reduced by 60% after 6 days. The rapid loss of WBCs was attributed to the accumulation of the catabolic intermediates maleylacetoacetate or maleylacetone (MA) in the circulation. Serum from GSTZ1-1 deficient mice treated with phenylalanine was cytotoxic to splenocytes from normal BALB/c mice and direct incubation of normal splenocytes with MA caused a rapid loss of viability. Dichloroacetic Acid (DCA) has been used therapeutically to treat lactic Acidosis and is potentially of use in cancer chemotherapy. Since DCA can inactivate GSTZ1-1 there is a possibility that long-term treatment of patients with DCA could cause GSTZ1-1 deficiency and susceptibility to oxidative stress and phenylalanine/tyrosine-induced WBC loss. However, although we found that DCA at 200mg/(kg day) causes a severe loss of hepatic GSTZ1-1 activity in BALB/c mice, it did not induce WBC cytotoxicity when combined with high dietary phenylalanine.

  • mass spectral characterization of Dichloroacetic Acid modified human glutathione transferase zeta
    Chemical Research in Toxicology, 2002
    Co-Authors: Wayne B Anderson, Philip G. Board, Daniel C Liebler, M. W. Anders
    Abstract:

    Glutathione transferase zeta (GSTZ1-1) is widely expressed in eukaryotic species, and four human allelic variants of hGSTZ1-1 have been described. GSTZ1-1 catalyzes the cis-trans isomerization of maleylacetoacetate to fumarylacetoacetate and the biotransformation of a range of alpha-haloalkanoic Acids. GSTZ1-1-catalyzed biotransformation of fluorine-lacking alpha,alpha-dihaloalkanoic Acids, including Dichloroacetic Acid (DCA), results in the mechanism-based inactivation and covalent modification of the enzyme. The objective of this study was to investigate further the DCA-induced inactivation of hGSTZ1c-1c and to explore the mechanism of inactivation by characterization of the sites and types of DCA-induced covalent modifications. The partition ratio for the DCA-induced, mechanism-based inactivation of hGSTZ1c-1c was (5.7 +/- 0.5) x 10(2), and the k(cat) for the biotransformation of DCA was 39 min(-)(1). Inactivation of hGSTZ1c-1c in vitro was limited at high enzyme concentrations and was inhibited by glyoxylate. The stoichiometry of DCA binding to hGSTZ1c-1c was approximately 0.5 mol of DCA/mol of enzyme monomer. A single DCA-derived adduct was observed and was assigned to cysteine-16 by a combination of matrix-assisted laser-desorption-ionization time-of-flight and electrospray-ionization quadrupole ion-trap mass spectrometry and by analysis of [1-(14)C]DCA binding to C16A hGSTZ1c-1c. The DCA-derived adduct contained both glutathione and the carbon skeleton of DCA, presumably in a dithioacetal linkage. Also, cysteine-16 formed a mixed disulfide bond with glutathione. These data support a mechanism of inactivation whereby glutathione displaces a chlorine atom from DCA, and cysteine-16 in the enzyme active site displaces the second chlorine atom to result in a covalently modified and inactivated enzyme. These findings explain the DCA-induced inactivation of GSTZ1-1 observed in humans and rats.

  • inactivation of glutathione transferase zeta by Dichloroacetic Acid and other fluorine lacking alpha haloalkanoic Acids
    Chemical Research in Toxicology, 1999
    Co-Authors: Warwick P Anderson, Philip G. Board, Bryan Gargano, M. W. Anders
    Abstract:

    Dichloroacetic Acid (DCA) is a contaminant of chlorinated drinking water supplies, is carcinogenic in rats and mice, and is a therapeutic agent used for the treatment of congenital lactic Acidosis. The biotransformation of DCA to glyoxylic Acid is catalyzed by glutathione transferase zeta (GSTZ). Treatment of rats and human subjects with DCA increases its plasma elimination half-life and reduces the extent of DCA biotransformation in rat hepatic cytosol. In the investigation presented here, the kinetics of the DCA-induced inactivation of GSTZ, the turnover of GSTZ, and the susceptibility of GSTZ to inactivation by a panel of α-haloAcids were studied. DCA rapidly inactivated GSTZ in both rat hepatic cytosol and intact Fischer 344 rats. The time course of inactivation in vivo was mirrored by a concomitant loss of immunoreactive GSTZ protein. The turnover of GSTZ in rat liver was 0.21 day-1, which corresponded to a half-life of 3.3 days. The degree of GSTZ inactivation after daily administration of DCA could...

  • glutathione transferase zeta catalyzed biotransformation of Dichloroacetic Acid and other alpha haloAcids
    Chemical Research in Toxicology, 1998
    Co-Authors: Zeen Tong, Philip G. Board, M. W. Anders
    Abstract:

    Dichloroacetic Acid (DCA) is a common drinking-water contaminant, is hepatocarcinogenic in rats and mice, and is a therapeutic agent used clinically in the management of lactic Acidosis. Recent studies show that glutathione transferase Zeta (GSTZ) catalyzes the oxygenation of DCA to glyoxylic Acid [Tong et al. (1998) Biochem. J. 331, 371-374]. In the present studies, the substrate selectivity of GSTZ, the kinetics of DCA metabolism, and the fate of DCA and glutathione were investigated. The results showed that GSTZ catalyzed the oxygenation of bromochloro-, bromofluoro-, chlorofluoro-, dibromo-, and Dichloroacetic Acid, but not difluoroacetic Acid, to glyoxylic Acid. GSTZ also catalyzed the biotransformation of fluoroacetic Acid to S-(carboxymethyl)glutathione, and of (R,S)-2-bromopropionic Acid, (R)-, (S)-, and (R,S)-2-chloropropionic Acid, and (R, S)-2-iodopropionic Acid, but not (R,S)-2-fluoropropionic Acid, to S-(alpha-methylcarboxymethyl)glutathione; and of 2, 2-dichloropropionic Acid to pyruvate. No biotransformation of 3, 3-dichloropropionic Acid was detected, and no GSTZ-catalyzed fluoride release from ethyl fluoroacetate and fluoroacetamide was observed. The relative rates of DCA biotransformation by hepatic cytosol were mouse > rat > human. Immunoblotting showed the presence of GSTZ in mouse, rat, and human liver cytosol. 13C NMR spectroscopic studies showed that [2-13C]glyoxylic Acid was the only observable, stable metabolite of [2-13C]DCA. Also, glutathione was required, but was neither consumed nor oxidized to glutathione disulfide, during the oxygenation of DCA to glyoxylic Acid. These results are consistent with a reaction mechanism that involves displacement of chloride from DCA by glutathione to afford S-(alpha-chlorocarboxymethyl)glutathione, which may undergo hydrolysis to give the hemithioacetal S-(alpha-hydroxycarboxymethyl)glutathione. Elimination of glutathione from the hemithioacetal would give glyoxylic Acid.

Ghassan M Saed - One of the best experts on this subject based on the ideXlab platform.

  • regulation of expression of tissue plasminogen activator and plasminogen activator inhibitor 1 by Dichloroacetic Acid in human fibroblasts from normal peritoneum and adhesions
    American Journal of Obstetrics and Gynecology, 2004
    Co-Authors: Michael P Diamond, Eslam Elhammady, Rona Wang, Michael Kruger, Ghassan M Saed
    Abstract:

    Abstract Objective As part of our ongoing studies to understand the biologic mechanisms of wound repair that lead to postoperative adhesions, we have identified characteristics of an adhesion phenotype that differs between fibroblasts that are obtained from human normal peritoneum and adhesions. In this study, we sought to examine whether stimulation of aerobic metabolism would alter differential expression of tissue plasminogen activator and plasminogen activator inhibitor–1, thereby creating a milieu likely to be less favorable to postoperative adhesion development. To examine this issue, we used a compound, Dichloroacetic Acid, that stimulates the pyruvate dehydrogenase complex, which causes pyruvate to be metabolized in the Kreb's cycle rather than being converted into lactate, thereby switching anaerobic to aerobic metabolism. Study design Human fibroblasts from normal peritoneum and adhesions were cultured in the absence or presence of Dichloroacetic Acid (100 μg/mL) for 24 hours, under normal and hypoxic (2% 0 2 ) conditions. Real-time reverse transcriptase–polymerase chain reaction of tissue plasminogen activator, plasminogen activator inhibitor–1, and a housekeeping gene β-actin was performed with messenger RNA that was extracted from all treatment points. Results Dichloroacetic Acid stimulated normal peritoneal fibroblast tissue plasminogen activator messenger RNA expression under hypoxic conditions. In adhesion fibroblasts, Dichloroacetic Acid treatment enhanced tissue plasminogen activator messenger RNA expression under both normoxic and hypoxic conditions. Plasminogen activator inhibitor–1 messenger RNA expression was unaltered by Dichloroacetic Acid in normoxic normal peritoneal fibroblasts; but during culture under hypoxic conditions, Dichloroacetic Acid reduced plasminogen activator inhibitor–1 messenger RNA expression. Similarly, in adhesion fibroblasts, Dichloroacetic Acid reduced plasminogen activator inhibitor–1 messenger RNA expression under both normoxic and hypoxic conditions. As a result, in normal peritoneal fibroblasts under hypoxic conditions and in adhesion fibroblasts under normoxic and hypoxic conditions, Dichloroacetic Acid greatly increased the tissue plasminogen activator/plasminogen activator inhibitor–1 ratios. Conclusion These findings confirm that fibroblasts from adhesions are characterized by reduced tissue plasminogen activator and increased plasminogen activator inhibitor–1 production. These observations are extended to show the stimulation of oxidative metabolism by Dichloroacetic Acid increases tissue plasminogen activator expression under hypoxic conditions. Dichloroacetic Acid reduces plasminogen activator inhibitor–1 production by hypoxic normal peritoneal fibroblasts and adhesion fibroblasts under hypoxic conditions. The resultant increases in the tissue plasminogen activator/plasminogen activator inhibitor–1 ratios would favor the development of a fibrinolytic milieu, which would be expected potentially to limit postoperative adhesion development. Thus, regulation of metabolic activity of peritoneal cells may provide a target for future interventions for the reduction of the development of postoperative adhesions, particularly as intervention relates to the healing of peritoneal sites that previously had adhesions. (eg, sites of potential adhesion reformation).

  • regulation of matrix metalloproteinase 1 and tissue inhibitor of matrix metalloproteinase 1 by Dichloroacetic Acid in human fibroblasts from normal peritoneum and adhesions
    Fertility and Sterility, 2004
    Co-Authors: Michael P Diamond, Eslam Elhammady, Rona Wang, Ghassan M Saed
    Abstract:

    Abstract Objective To examine the role of stimulation of aerobic metabolism on the differential expression of matrix metalloproteinase–1 (MMP-1) and tissue inhibitor of matrix metalloproteinase-1 (TIMP-1), which are differentially regulated in fibroblasts isolated from normal human peritoneum and adhesions. Design Tissue culture study. Setting University research laboratory. Patient(s) Human fibroblasts cultures from normal peritoneum and adhesions that were exposed to Dichloroacetic Acid (DCA; 0 and 100 μg/mL) for 24 hours under normal and hypoxic conditions. Intervention(s) Main outcome measure(s) Real-time reverse-transcription polymerase chain reaction of MMP-1, TIMP-1, and β-actin. Result(s) Dichloroacetic Acid stimulated peritoneal fibroblast MMP-1 mRNA expression under normoxic conditions; this stimulation was lost during hypoxia. In adhesion fibroblasts, DCA increased MMP-1 mRNA expression; this effect was reversed by hypoxia. Expression of TIMP-1 mRNA was insignificantly increased by DCA in normal peritoneal and adhesion fibroblasts under normoxic conditions; however under hypoxic conditions, DCA reduced TIMP-1 mRNA expression from both. Conclusion(s) Regulation of metabolic activity of peritoneal cells may provide a target for future interventions for reduction of development of postoperative adhesions, particularly as it relates to healing of peritoneal sites that did not previously have adhesions as opposed to sites that underwent lysis of preexistent adhesions.

  • regulation of transforming growth factor beta type iii collagen and fibronectin by Dichloroacetic Acid in human fibroblasts from normal peritoneum and adhesions
    Fertility and Sterility, 2003
    Co-Authors: Michael P Diamond, Eslam Elhammady, Rona Wang, Ghassan M Saed
    Abstract:

    Abstract Objective To examine the role of aerobic metabolism in fibroblasts from normal peritoneum and adhesions in the differential expression of extracellular matrix (ECM) and transforming growth factor-beta (TGF-β), an inflammatory cytokine that regulates ECM expression. Design Cell culture under normoxic and hypoxic conditions. Setting University research laboratory. Patient(s) Human fibroblasts cultures from normal peritoneum and adhesions. Intervention(s) Exposure to Dichloroacetic Acid (DCA), which activates pyruvate dehydrogenase, for 24 hours under normal and hypoxic (2% O 2 ) conditions. Main outcome measure(s) Multiplex reverse transcriptase polymerase chain reaction (RT/PCR) of type III collagen, fibronectin, TGF-β1, and β-actin was performed, with analysis of PCR-amplified products performed by densimetric analysis of gel bands using the National Institutes of Health Image analysis program. Result(s) DCA inhibited human peritoneal fibroblast and adhesion fibroblast TGF-β1 mRNA expression under normoxic and hypoxic conditions. DCA also markedly reduced fibronectin and type III collagen expression under hypoxic conditions in fibroblasts from normal peritoneum and adhesions. Conclusion(s) These observations provide further support for the suggestion that regulation of metabolic activity of peritoneal cells may provide a target for interventions designed to reduce postoperative adhesions.