Publications by authors named "Miriam Cantore"

16 Publications

  • Page 1 of 1

Optical analysis of cellular oxygen sensing.

Exp Cell Res 2017 07 8;356(2):122-127. Epub 2017 Mar 8.

Institute of Physiology, University of Duisburg-Essen, Essen, Germany. Electronic address:

Molecular imaging of the assembly of hypoxia inducible factor (HIF) complexes in living cells may lead to a deeper understanding of cellular oxygen sensing. Sophisticated live cell imaging has extended the toolbox to study the molecular response to changes in oxygen supply. In this respect fluorescence resonance energy transfer (FRET) as a technique to investigate protein-protein interaction in the nanoscale range gets increasing interest. Herein, we review FRET studies related to hypoxia research, emphasizing on recent progress, but also demonstrating how FRET studies are complementary or potentially superior to conventional biochemical as well as histochemical techniques. Technical advances in the application of FRET in living cells will overcome restrictions to end-point analysis on the population rather than single cell level and will thereby provide progress in understanding the cellular hypoxic response by HIF.
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http://dx.doi.org/10.1016/j.yexcr.2017.03.009DOI Listing
July 2017

Regulation of plasma membrane localization of the Na+-taurocholate cotransporting polypeptide (Ntcp) by hyperosmolarity and tauroursodeoxycholate.

J Biol Chem 2015 Oct 25;290(40):24237-54. Epub 2015 Aug 25.

From the Clinic for Gastroenterology, Hepatology and Infectious Diseases, Heinrich-Heine-University Düsseldorf, 40225 Düsseldorf, Germany

In perfused rat liver, hepatocyte shrinkage induces a Fyn-dependent retrieval of the bile salt export pump (Bsep) and multidrug resistance-associated protein 2 (Mrp2) from the canalicular membrane (Cantore, M., Reinehr, R., Sommerfeld, A., Becker, M., and Häussinger, D. (2011) J. Biol. Chem. 286, 45014-45029) leading to cholestasis. However little is known about the effects of hyperosmolarity on short term regulation of the Na(+)-taurocholate cotransporting polypeptide (Ntcp), the major bile salt uptake system at the sinusoidal membrane of hepatocytes. The aim of this study was to analyze hyperosmotic Ntcp regulation and the underlying signaling events. Hyperosmolarity induced a significant retrieval of Ntcp from the basolateral membrane, which was accompanied by an activating phosphorylation of the Src kinases Fyn and Yes but not of c-Src. Hyperosmotic internalization of Ntcp was sensitive to SU6656 and PP-2, suggesting that Fyn mediates Ntcp retrieval from the basolateral membrane. Hyperosmotic internalization of Ntcp was also found in livers from wild-type mice but not in p47(phox) knock-out mice. Tauroursodeoxycholate (TUDC) and cAMP reversed hyperosmolarity-induced Fyn activation and triggered re-insertion of the hyperosmotically retrieved Ntcp into the membrane. This was associated with dephosphorylation of the Ntcp on serine residues. Insertion of Ntcp by TUDC was sensitive to the integrin inhibitory hexapeptide GRGDSP and inhibition of protein kinase A. TUDC also reversed the hyperosmolarity-induced retrieval of bile salt export pump from the canalicular membrane. These findings suggest a coordinated and oxidative stress- and Fyn-dependent retrieval of sinusoidal and canalicular bile salt transport systems from the corresponding membranes. Ntcp insertion was also identified as a novel target of β1-integrin-dependent TUDC action, which is frequently used in the treatment of cholestatic liver disease.
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http://dx.doi.org/10.1074/jbc.M115.666883DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4591811PMC
October 2015

Therapeutic effects of the superoxide dismutase mimetic compound MnIIMe2DO2A on experimental articular pain in rats.

Mediators Inflamm 2013 6;2013:905360. Epub 2013 Jun 6.

Department of Pharmacology, University of Florence, Viale Pieraccini 6, 50139 Florence, Italy.

Superoxide anion (O(2) (•-)) is overproduced in joint inflammation, rheumatoid arthritis, and osteoarthritis. Increased O(2) (•-) production leads to tissue damage, articular degeneration, and pain. In these conditions, the physiological defense against O(2) (•-), superoxide dismutases (SOD) are decreased. The Mn(II) complex MnL4 is a potent SOD mimetic, and in this study it was tested in inflammatory and osteoarticular rat pain models. In vivo protocols were approved by the animal Ethical Committee of the University of Florence. Pain was measured by paw pressure and hind limb weight bearing alterations tests. MnL4 (15 mg kg(-1)) acutely administered, significantly reduced pain induced by carrageenan, complete Freund's adjuvant (CFA), and sodium monoiodoacetate (MIA). In CFA and MIA protocols, it ameliorated the alteration of postural equilibrium. When administered by osmotic pump in the MIA osteoarthritis, MnL4 reduced pain, articular derangement, plasma TNF alpha levels, and protein carbonylation. The scaffold ring was ineffective. MnL4 (10(-7) M) prevented the lipid peroxidation of isolated human chondrocytes when O(2) (•-) was produced by RAW 264.7. MnL4 behaves as a potent pain reliever in acute inflammatory and chronic articular pain, being its efficacy related to antioxidant property. Therefore MnL4 appears as a novel protective compound potentially suitable for the treatment of joint diseases.
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http://dx.doi.org/10.1155/2013/905360DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3690261PMC
February 2014

The Src family kinase Fyn mediates hyperosmolarity-induced Mrp2 and Bsep retrieval from canalicular membrane.

J Biol Chem 2011 Dec 4;286(52):45014-29. Epub 2011 Nov 4.

Clinic for Gastroenterology, Hepatology, and Infectiology, Heinrich-Heine-University Düsseldorf, D-40225 Düsseldorf, Germany.

In perfused rat liver, hyperosmolarity induces Mrp2- (Kubitz, R., D'urso, D., Keppler, D., and Häussinger, D. (1997) Gastroenterology 113, 1438-1442) and Bsep retrieval (Schmitt, M., Kubitz, R., Lizun, S., Wettstein, M., and Häussinger, D. (2001) Hepatology 33, 509-518) from the canalicular membrane leading to cholestasis. The aim of this study was to elucidate the underlying signaling events. Hyperosmolarity-induced retrieval of Mrp2 and Bsep from the canalicular membrane in perfused rat liver was accompanied by an activating phosphorylation of the Src kinases Fyn and Yes but not of c-Src. Both hyperosmotic transporter retrieval and Src kinase activation were sensitive to apocynin (300 μmol/liter), N-acetylcysteine (NAC; 10 mmol/liter), and SU6656 (1 μmol/liter). Also PP-2 (250 nmol/liter), which inhibited hyperosmotic Fyn but not Yes activation, prevented hyperosmotic transporter retrieval from the canalicular membrane, suggesting that Fyn but not Yes mediates hyperosmotic Bsep and Mrp2 retrieval. Neither hyperosmotic Fyn activation nor Bsep/Mrp2 retrieval was observed in livers from p47(phox) knock-out mice. Hyperosmotic activation of JNKs was sensitive to apocynin and NAC but insensitive to SU6656 and PP-2, indicating that JNKs are not involved in transporter retrieval, as also evidenced by experiments using the JNK inhibitors L-JNKI-1 and SP6001255, respectively. Hyperosmotic transporter retrieval was accompanied by a NAC and Fyn knockdown-sensitive inhibition of biliary excretion of the glutathione conjugate of 1-chloro-2,4-dinitrobenzene in perfused rat liver and of cholyl-L-lysyl-fluorescein secretion into the pseudocanaliculi formed by hepatocyte couplets. Hyperosmolarity triggered an association between Fyn and cortactin and increased the amount of phosphorylated cortactin underneath the canalicular membrane. It is concluded that the hyperosmotic cholestasis is triggered by a NADPH oxidase-driven reactive oxygen species formation that mediates Fyn-dependent retrieval of the Mrp2 and Bsep from the canalicular membrane, which may involve an increased cortactin phosphorylation.
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http://dx.doi.org/10.1074/jbc.M111.292896DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3247936PMC
December 2011

Aldehyde dehydrogenase 7A1 (ALDH7A1) attenuates reactive aldehyde and oxidative stress induced cytotoxicity.

Chem Biol Interact 2011 May 19;191(1-3):269-77. Epub 2011 Feb 19.

Department of Pharmaceutical Sciences, University of Colorado Denver, Aurora, CO 80045, USA.

Mammalian aldehyde dehydrogenase 7A1 (ALDH7A1) is homologous to plant ALDH7B1 which protects against various forms of stress such as increased salinity, dehydration and treatment with oxidants or pesticides. Deleterious mutations in human ALDH7A1 are responsible for pyridoxine-dependent and folinic acid-responsive seizures. In previous studies, we have shown that human ALDH7A1 protects against hyperosmotic stress presumably through the generation of betaine, an important cellular osmolyte, formed from betaine aldehyde. Hyperosmotic stress is coupled to an increase in oxidative stress and lipid peroxidation (LPO). In this study, cell viability assays revealed that stable expression of mitochondrial ALDH7A1 in Chinese hamster ovary (CHO) cells provides significant protection against treatment with the LPO-derived aldehydes hexanal and 4-hydroxy-2-nonenal (4HNE) implicating a protective function for the enzyme during oxidative stress. A significant increase in cell survival was also observed in CHO cells expressing either mitochondrial or cytosolic ALDH7A1 treated with increasing concentrations of hydrogen peroxide (H(2)O(2)) or 4HNE, providing further evidence for anti-oxidant activity. In vitro enzyme activity assays indicate that human ALDH7A1 is sensitive to oxidation and that efficiency can be at least partially restored by incubating recombinant protein with the thiol reducing agent β-mercaptoethanol (BME). We also show that after reactivation with BME, recombinant ALDH7A1 is capable of metabolizing the reactive aldehyde 4HNE. In conclusion, ALDH7A1 mechanistically appears to provide cells protection through multiple pathways including the removal of toxic LPO-derived aldehydes in addition to osmolyte generation.
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http://dx.doi.org/10.1016/j.cbi.2011.02.016DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3387551PMC
May 2011

Aldehyde dehydrogenase 7A1 (ALDH7A1) is a novel enzyme involved in cellular defense against hyperosmotic stress.

J Biol Chem 2010 Jun 5;285(24):18452-63. Epub 2010 Mar 5.

Department of Pharmaceutical Sciences, University of Colorado Denver, Aurora, Colorado 80045, USA.

Mammalian ALDH7A1 is homologous to plant ALDH7B1, an enzyme that protects against various forms of stress, such as salinity, dehydration, and osmotic stress. It is known that mutations in the human ALDH7A1 gene cause pyridoxine-dependent and folic acid-responsive seizures. Herein, we show for the first time that human ALDH7A1 protects against hyperosmotic stress by generating osmolytes and metabolizing toxic aldehydes. Human ALDH7A1 expression in Chinese hamster ovary cells attenuated osmotic stress-induced apoptosis caused by increased extracellular concentrations of sucrose or sodium chloride. Purified recombinant ALDH7A1 efficiently metabolized a number of aldehyde substrates, including the osmolyte precursor, betaine aldehyde, lipid peroxidation-derived aldehydes, and the intermediate lysine degradation product, alpha-aminoadipic semialdehyde. The crystal structure for ALDH7A1 supports the enzyme's substrate specificities. Tissue distribution studies in mice showed the highest expression of ALDH7A1 protein in liver, kidney, and brain, followed by pancreas and testes. ALDH7A1 protein was found in the cytosol, nucleus, and mitochondria, making it unique among the aldehyde dehydrogenase enzymes. Analysis of human and mouse cDNA sequences revealed mitochondrial and cytosolic transcripts that are differentially expressed in a tissue-specific manner in mice. In conclusion, ALDH7A1 is a novel aldehyde dehydrogenase expressed in multiple subcellular compartments that protects against hyperosmotic stress by generating osmolytes and metabolizing toxic aldehydes.
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http://dx.doi.org/10.1074/jbc.M109.077925DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2881771PMC
June 2010

A novel manganese complex effective as superoxide anion scavenger and therapeutic agent against cell and tissue oxidative injury.

J Med Chem 2009 Nov;52(22):7273-83

Department of Preclinical and Clinical Pharmacology, University of Florence, V. le G. Pieraccini 6, Florence, Italy.

Two cyclic polyamine-polycarboxylate ligands, 1,4,7,10-tetraazacyclododecane-1,7-diacetic acid (H(2)L3) and 4,10-dimethyl-1,4,7,10-tetraazacyclododecane-1,7-diacetic acid (H(2)L4), and two noncyclic scaffolds, N-(2-hydroxyethyl)ethylenediamine-N,N',N'-triacetic acid (H(3)L1) and ethylene-bisglycol-tetracetic acid (H(4)L2), form stable complexes with Mn(II) in aqueous solutions. Cyclic voltammograms show that the complexes with the most hydrophobic ligands, [MnL2](2-) and [MnL4], are oxidized at higher potential than [MnL1](-) and [MnL3]. The pharmacological properties of these molecules were evaluated as superoxide ion scavengers and anti-inflammatory compounds. Among the four complexes, [MnL4] was the most bioactive, being effective in the nanomolar/micromolar range. It abates the levels of key markers of oxidative injury on cultured cells and ameliorates the outcome parameters in animal models of acute and chronic inflammation. [MnL4] toxicity was very low on both cell cultures in vitro and mice in vivo. Hence, we propose [MnL4] as a novel stable oxygen radical scavenging molecule, active at low doses and with a low toxicity.
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http://dx.doi.org/10.1021/jm901298xDOI Listing
November 2009

Corneal aldehyde dehydrogenases: multiple functions and novel nuclear localization.

Brain Res Bull 2010 Feb 29;81(2-3):211-8. Epub 2009 Aug 29.

Molecular Toxicology and Environmental Health Sciences Program, Department of Pharmaceutical Sciences, University of Colorado Denver, Aurora, CO, USA.

Aldehyde dehydrogenases (ALDHs) represent a superfamily of NAD(P)(+)-dependent enzymes which catalyze the oxidation of a wide variety of endogenous and exogenous aldehydes to their corresponding acids. Some ALDHs have been identified as corneal crystallins and thereby contribute to the protective and refractive properties of the cornea. ALDH3A1 is highly expressed in the cornea of most mammals with the exception of rabbit that abundantly expresses ALDH1A1 in the cornea instead of ALDH3A1. In this study, we examined the gene expression of other ALDHs and found high messenger levels of ALDH1B1, ALDH2 and ALDH7A1 in mouse cornea and lens. Substantial evidence supports a protective role for ALDH3A1 and ALDH1A1 against ultraviolet radiation (UVR)-induced oxidative damage to ocular tissues. The mechanism by which this protection occurs includes UVR filtering, detoxification of reactive aldehydes generated by UVR exposure and antioxidant activity. We recently have identified ALDH3A1 as a nuclear protein in corneal epithelium. Herein, we show that ALDH3A1 is also found in the nucleus of rabbit keratocytes. The nuclear presence of ALDH3A1 may be involved in cell cycle regulation.
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http://dx.doi.org/10.1016/j.brainresbull.2009.08.017DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3025408PMC
February 2010

Synthesis of new pyrazolo[5,1-c][1,2,4] benzotriazines, pyrazolo[5,1-c]pyrido[4,3-e][1,2,4] triazines and their open analogues as cytotoxic agents in normoxic and hypoxic conditions.

Bioorg Med Chem 2008 Nov 26;16(21):9409-19. Epub 2008 Sep 26.

Dipartimento di Scienze Farmaceutiche, Università degli Studi di Firenze, Via U. Schiff 6, 50019 Polo Scientifico, Sesto Fiorentino, Firenze, Italy.

The synthesis and antitumor activity in normoxic and hypoxic conditions of a series of pyrazolo[5,1-c][1,2,4]benzotriazine and its related analogues are reported. All compounds were tested on human colorectal adenocarcinoma cell line HCT-8 and for compounds 15 and 20, which show to have selective cytotoxicity in hypoxic and in normoxic conditions respectively, ROS production, cell cycle, and DNA fragmentation were measured. This preliminary study encouraged us to consider 15 and 20 as interesting leads for further optimization.
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http://dx.doi.org/10.1016/j.bmc.2008.09.055DOI Listing
November 2008

Polyamine-polycarboxylate metal complexes with different biological effectiveness as nitric oxide scavengers. Clues for drug design.

J Med Chem 2008 Jun 17;51(11):3250-60. Epub 2008 May 17.

Department of Chemistry, University of Florence, Sesto Fiorentino, Florence, Italy.

The synthesis of the Fe(III), Co(II), Mn(II), and Ru(III) complexes with two polyamine-polycarboxylate ligands, N-(2-hydroxyethyl)ethylenediamine-N, N', N'-triacetic acid (H3L1) and ethylene bisglycol tetraacetic acid (H4L2) is reported. Potentiometric studies showed that these ligands form stable complexes in aqueous solution and no metal release occurs, thus accounting for their low toxicity in cultured RAW 264.7 macrophages. X-ray characterization of the [Co(L1)](-) complex showed that binding sites are available at the metal for NO binding. Efficiency of these compounds to bind NO was studied by UV-vis spectrophotometry. Then their NO-scavenging properties were assayed in a cell-free system under physiological conditions, using S-nitroso-N-acetyl-D,L-penicillamine (SNAP) as NO source. The L1 complexes caused the most effective reduction of free NO, [Mn(L1)](-) being the most efficient. Conversely, in NOS II induced RAW 264.7 macrophages, the Ru(III) and Co(II) complexes with L2 were the most effective compounds. [Ru(L2)](-) also afforded significant protection against lipopolysaccharide-induced endotoxic shock in the mouse in vivo.
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http://dx.doi.org/10.1021/jm701553uDOI Listing
June 2008

Pyrido[1,2-a]pyrimidin-4-one derivatives as a novel class of selective aldose reductase inhibitors exhibiting antioxidant activity.

J Med Chem 2007 Oct 11;50(20):4917-27. Epub 2007 Sep 11.

Dipartimento di Scienze Farmaceutiche, Università di Pisa, Via Bonanno 6, 56126 Pisa, Italy.

2-Phenyl-pyrido[1,2-a]pyrimidin-4-one derivatives bearing a phenol or a catechol moiety in position 2 were tested as aldose reductase (ALR2) inhibitors and exhibited activity levels in the micromolar/submicromolar range. Introduction of a hydroxy group in position 6 or 9 gave an enhancement of the inhibitory potency (compare 18, 19, 28, and 29 vs 13 and 14). Lengthening of the 2-side chain to benzyl determined a general reduction in activity. The lack or the methylation of the phenol or catechol hydroxyls gave inactive (10-12, 21, 22, 25-27) or scarcely active (15, 17, 20) compounds, thus demonstrating that the phenol or catechol hydroxyls are involved in the enzyme pharmacophoric recognition. Moreover, all the pyridopyrimidinones displayed significant antioxidant properties, with the best activity shown by the catechol derivatives. The theoretical binding mode of the most active compounds obtained by docking simulations into the ALR2 crystal structure was fully consistent with the structure-activity relationships in the pyrido[1,2-a]pyrimidin-4-one series.
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http://dx.doi.org/10.1021/jm070398aDOI Listing
October 2007

Mechanisms involved in the protection of UV-induced protein inactivation by the corneal crystallin ALDH3A1.

J Biol Chem 2007 Feb 11;282(7):4382-4392. Epub 2006 Dec 11.

Center for Pharmaceutical Biotechnology and Department of Pharmaceutical Sciences, University of Colorado Health Sciences Center, Denver, Colorado 80262; Molecular Toxicology and Environmental Health Sciences Program, Department of Pharmaceutical Sciences, University of Colorado Health Sciences Center, Denver, Colorado 80262 and the. Electronic address:

Various lines of evidence have shown that ALDH3A1 (aldehyde dehydrogenase 3A1) plays a critical and multifaceted role in protecting the cornea from UV-induced oxidative stress. ALDH3A1 is a corneal crystallin, which is defined as a protein recruited into the cornea for structural purposes without losing its primary function (i.e. metabolism). Although the primary role of ALDH3A1 in the metabolism of toxic aldehydes has been clearly demonstrated, including the detoxification of aldehydes produced during UV-induced lipid peroxidation, the structural role of ALDH3A1 in the cornea remains elusive. We therefore examined the potential contribution of ALDH3A1 in maintaining the optical integrity of the cornea by suppressing the aggregation and/or inactivation of other proteins through chaperone-like activity and other protective mechanisms. We found that ALDH3A1 underwent a structural transition near physiological temperatures to form a partially unfolded conformation that is suggestive of chaperone activity. Although this structural transition alone did not correlate with any protection, ALDH3A1 substantially reduced the inactivation of glucose-6-phosphate dehydrogenase by 4-hydroxy-2-nonenal and malondialdehyde when co-incubated with NADP(+), reinforcing the importance of the metabolic function of this corneal enzyme in the detoxification of toxic aldehydes. A large excess of ALDH3A1 also protected glucose-6-phosphate dehydrogenase from inactivation because of direct exposure to UVB light, which suggests that ALDH3A1 may shield other proteins from damaging UV rays. Collectively, these data demonstrate that ALDH3A1 can reduce protein inactivation and/or aggregation not only by detoxification of reactive aldehydes but also by directly absorbing UV energy. This study provides for the first time mechanistic evidence supporting the structural role of the corneal crystallin ALDH3A1 as a UV-absorbing constituent of the cornea.
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http://dx.doi.org/10.1074/jbc.M607546200DOI Listing
February 2007

Scallop lens Omega-crystallin (ALDH1A9): a novel tetrameric aldehyde dehydrogenase.

Biochem Biophys Res Commun 2006 Oct 8;348(4):1302-9. Epub 2006 Aug 8.

Jules Stein Eye Institute, UCLA School of Medicine, Los Angeles, CA 90095-7008, USA.

Scallop eye lens Omega-crystallin is an inactive aldehyde dehydrogenase (ALDH1A9) related to cytoplasmic ALDH1A1 and mitochondrial ALDH2 that migrates by gel filtration chromatography as a homodimer. Because mammalian ALDH1A1 and ALDH2 are homotetramers, we investigated the native molecular mass of scallop Omega-crystallin by multi-angle laser light scattering. The results indicate that the scallop Omega-crystallin is a tetrameric, not a dimeric protein. Moreover, phylogenetic tree analysis shows that scallop Omega-crystallin clusters with the mitochondrial ALDH2 and ALDH1B1 rather than the cytoplasmic ALDH1A, yet it lacks the mitochondrial N-terminal leader sequence characteristic of the mitochondrial ALDHs. The mitochondrial grouping, enzymatic inactivity, and anomalous gel filtration behavior make scallop cytoplasmic Omega-crystallin an interesting protein for structural studies of evolutionary adaptations to become an enzyme-crystallin.
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http://dx.doi.org/10.1016/j.bbrc.2006.07.197DOI Listing
October 2006

Pirenoxine prevents oxidative effects of argon fluoride excimer laser irradiation in rabbit corneas: biochemical, histological and cytofluorimetric evaluations.

J Photochem Photobiol B 2005 Jan;78(1):35-42

Department of Preclinical and Clinical Pharmacology, University of Florence, V.le Pierraccini, 6, Florence, Italy.

The production of reactive oxygen species (ROS) associated with excimer laser irradiation is recognized as a possible cause of corneal haze following photorefractive keratectomy (PRK). Our work was aimed at investigating in vitro the oxidative effects induced by subablative laser fluences and at demonstrating the protective effectiveness of pirenoxine. Comparative trials of subablative fluence on rabbit eyes with or without 10(-5) M pirenoxine were carried out. Superoxide anion (O(2)(-)), conjugated diene (CD), and thiobarbituric acid reagent substance (TBARS) formation were analyzed. Cellular death was evaluated by flow cytometry. Histological examinations were also performed. No appraisable differences in O(2)(-),CD,andTBARS formation were detected soon after irradiation, whereas they all increased following incubation. Pirenoxine inhibited such increases. Cytofluorimetric and histological observations gave coherent results. The experimental data indicate that oxidative and toxic effects are ascribable to ROS avalanches triggered by laser irradiation-induced photodissociation and are inhibited by pirenoxine.
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http://dx.doi.org/10.1016/j.jphotobiol.2004.09.005DOI Listing
January 2005

Antioxidant protection in cultured corneal cells and whole corneas submitted to UV-B exposure.

J Photochem Photobiol B 2003 Oct;71(1-3):59-68

Department of Preclinical and Clinical Pharmacology, University of Florence, V.le Pieraccini 6, Florence 50139, Italy.

Several corneal pathologies are characterized by the presence of reactive oxygen species (ROS); therefore, we evaluated the protection afforded by pirenoxine and melatonin to corneal cell culture and whole rabbit cornea from ultraviolet exposure and other oxidant systems. Rabbit cornea cell (SIRC) plates and whole corneas were exposed to UV-B (80 or 800 mJ/cm2) or incubated with fMLP-stimulated autologous macrophages, in the presence or absence of pirenoxine or melatonin (10(-5) M). The protective activity of compounds was assessed by measuring superoxide anion formation, inhibition of oxidation and mitochondrial viability. Moreover the ex vivo protective effect of pirenoxine and melatonin was verified in the whole cornea submitted to UV-B exposure in vitro. Our experimental data demonstrate that pirenoxine and melatonin were able to inhibit the superoxide formation and oxidative effect in cell culture and whole rabbit corneas submitted to UV-B exposure or to incubation with fMLP-stimulated autologous macrophages. Mitochondrial viability was restored in epithelial cells of rabbit cornea but not in SIRCs. Moreover, both compounds are also able to increase ex vivo epithelial corneal cell defences against the in vitro UV-B induced lipid peroxidation.
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http://dx.doi.org/10.1016/j.jphotobiol.2003.07.004DOI Listing
October 2003