RESUMO
The aim of this work was to design and characterize cross-linked hyaluronic acid (HA)-itaconic acid (IT) films loaded with dexamethasone sodium phosphate salt (DEX) for topical therapy of inflammatory ocular surface diseases. Films were chemically cross-linked with polyethylene glycol diglycidyl ether (PEGDE), then physical and mechanical characterization by stress-strain, X-ray diffraction, X-ray fluorescence spectrometry and swelling assays was conducted. A sequential in vitro therapeutic efficacy model was designed to assess changes in interleukin (IL)-6 production in an inflamed human corneal epithelial (HCE) cell line after film exposure. Changes in cell proliferation after film exposure were assessed using the alamarBlue(®) proliferation assay. Experimental findings showed desirable mechanical properties and in vitro efficacy to reduce cell inflammation. A moderately decreased proliferation rate was induced in HCE cells by DEX-loaded films, compared to commercial DEX eye drops. These results suggest that DEX and HA have opposite effects. The sequential in vitro therapeutic efficacy model arises as an efficient tool to study drug release from delivery systems by indirect measurement of a biological response.
Assuntos
Córnea/efeitos dos fármacos , Dexametasona/análogos & derivados , Ácido Hialurônico/química , Soluções Oftálmicas/administração & dosagem , Soluções Oftálmicas/química , Administração Tópica , Linhagem Celular , Proliferação de Células/efeitos dos fármacos , Dexametasona/administração & dosagem , Dexametasona/química , Humanos , Inflamação/tratamento farmacológico , Succinatos/químicaRESUMO
New hyaluronic acid (HA)-itaconic acid (IT) films have been previously synthesized and used as potential topical drug delivery systems (DDS) for ocular administration. In this study we explored homogeneous and heterogeneous crosslinking reactions of HA using glutaraldehyde (GTA) and polyethylene glycol diglycidyl ether (PEGDE) in the presence of IT, a naturally occurring compound that is non-toxic and readily biodegradable. We have studied the morphology, mechanical properties and in vitro biocompatibility between these new materials and ocular surface cells (human corneal epithelial cell line) and evaluated the biopharmaceutical performance of the designed formulations. Although all the synthesized materials exhibited good mechanical properties, the PEGDE modified films exhibited the best biocompatibility, with in vivo assays showing good adhesive performance and minimal irritation. PEGDE films were also tested for their effects in the treatment of intraocular pressure (IOP) in rabbits using timolol maleate (TM) as the model drug. These results may be useful for further design of novel bioadhesive matrix containing drugs by topical application in ophthalmology.
Assuntos
Anti-Hipertensivos/administração & dosagem , Sistemas de Liberação de Medicamentos , Resinas Epóxi/química , Ácido Hialurônico/química , Succinatos/química , Timolol/administração & dosagem , Adesividade , Administração Oftálmica , Animais , Anti-Hipertensivos/química , Linhagem Celular , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Glutaral/química , Humanos , Pressão Intraocular/efeitos dos fármacos , Coelhos , Timolol/químicaRESUMO
In previous studies from our laboratory we reported the presence in highly purified liver nuclei, free of contamination with other organelles, of an ethanol metabolizing system (NEMS) able to lead to acetaldehyde and 1-hydroxyethyl free radicals (1HEt). In the present study we tested whether this NEMS is inducible by chronic alcohol administration to rats and whether these nuclei also have increased ability to bioactivate N-nitrosodimethylamine (NDMA). Sprague Dawley male rats (125-150g) were fed with a nutritionally adequate liquid diet containing alcohol to provide 36% of total energy (standard Lieber-De Carli rat diet), for 28 days. Controls received an isocaloric diet without alcohol. Animals were sacrificed, livers were excised and microsomes and purified nuclear fractions were prepared. Both microsomes and nuclei from treated animals had significantly increased ability compared to controls, to biotransform ethanol to acetaldehyde using NADPH as cofactor under an air atmosphere. Both organelles also exhibited significantly increased capacity compared to controls, to bioactivate NDMA to formaldehyde and to reactive metabolites that bind covalently to proteins. Nuclear preparations from control animals were also able to metabolize NDMA to formaldehyde and reactive metabolites. Results indicate that liver nuclei may have a CYP2E1 able to bioactivate both NDMA and EtOH and that these processes are being induced by chronic alcohol drinking. The bioactivation of these xenobiotics to reactive metabolites in the neighborhood of nuclear proteins and DNA might have significant toxicological implications.
Assuntos
Núcleo Celular/metabolismo , Citocromo P-450 CYP2E1/metabolismo , Dimetilnitrosamina/metabolismo , Etanol/metabolismo , Fígado/metabolismo , N-Metilaspartato/metabolismo , Acetaldeído/metabolismo , Animais , Biotransformação , Isótopos de Carbono , Núcleo Celular/enzimologia , Doença Crônica , DNA/metabolismo , Dieta , Etanol/farmacocinética , Formaldeído/metabolismo , Metabolismo dos Lipídeos , Masculino , Microssomos Hepáticos/metabolismo , NADP/metabolismo , Ratos , Ratos Sprague-DawleyRESUMO
Administration of the radioprotective agent 2-(3-aminopropylamino) ethylphosphorothioic acid (WR2721) at 3 or 6 hr after carbon tetrachloride (CCl4) administration significantly prevented the liver necrosis produced by the hepatotoxin at 24 hr. It is well known that WR2721 does not exert or minimally exerts a protective activity by itself. The compound is activated through dephosphorylation to the free thiol WR1065, a process which is catalyzed by an alkaline phosphatase. We observed that this enzyme was widely distributed in the rat body. The WR2721 pretreatment 30 min before CCl4 administration modified the CCl4 levels reaching the liver at 1 hr of poisoning and exerted a significant increase in the covalent binding (CB) of 14CCl4-reactive metabolites to microsomal lipids at 3 hr. WR2721 did not modify the intensity of the CCl4-induced lipid peroxidation (LP) process at 1 or 3 hr of poisoning. CCl4-induced fat accumulation was not prevented when WR2721 was given 6 hr after CCl4. In fact, protection might be due to a favorable modulation of late events occurring after CB or LP, events that remain to be elucidated.
Assuntos
Amifostina/administração & dosagem , Hepatopatias/prevenção & controle , Fígado/efeitos dos fármacos , Necrose , Protetores contra Radiação/administração & dosagem , Fosfatase Alcalina/efeitos dos fármacos , Fosfatase Alcalina/metabolismo , Animais , Tetracloreto de Carbono , Doença Hepática Induzida por Substâncias e Drogas , Metabolismo dos Lipídeos , Peroxidação de Lipídeos/efeitos dos fármacos , Fígado/química , Fígado/patologia , Masculino , Microssomos/efeitos dos fármacos , Microssomos/metabolismo , Ratos , Ratos Sprague-DawleyRESUMO
Administration of the radioprotective agent 2-aminoethyl-isothiouronium bromide hydrobromide (AET) (240 mg/kg, i.p. in saline 30 min before or 6 or 10 h after CCl4 (1 ml/kg i.p. as a 20% v/v solution in olive oil) significantly prevented the necrogenic effect of the hepatotoxin at 24 h. Protection was more intense when the drug was given 6 h after CCl4 than when administered 30 min before. CCl4-induced fat accumulation was prevented only when AET was given 30 min before. AET did not prevent the CCl4-induced initiation of a lipid peroxidation (LP) process as evidenced by diene hyperconjugation of microsomal lipids. AET pretreatment 30 min before CCl4 did not significantly modify the CCl4 levels reaching the liver and only exerted a transient significant effect on the covalent binding of [14C]Cl4 reactive metabolites to microsomal lipids (CB) at 1 h but not at 3 h. The markedly intense protective effects of AET when given 6 or 10 h after CCl4 can not be attributed to decreased amounts of CCl4 reaching the liver or to decreasing effects in CB or to chain breaking effects in LP. Really, protection might be due to a favorable modulation of late events occurring after CB or LP, events that remain to be elucidated.
Assuntos
Intoxicação por Tetracloreto de Carbono/prevenção & controle , Doença Hepática Induzida por Substâncias e Drogas , Hepatopatias/prevenção & controle , Fígado/efeitos dos fármacos , beta-Aminoetil Isotioureia/uso terapêutico , Animais , Intoxicação por Tetracloreto de Carbono/metabolismo , Peroxidação de Lipídeos/efeitos dos fármacos , Fígado/patologia , Hepatopatias/patologia , Masculino , Microssomos Hepáticos/efeitos dos fármacos , Microssomos Hepáticos/enzimologia , Microssomos Hepáticos/metabolismo , Necrose , Ratos , Ratos Sprague-DawleyRESUMO
N-Acetyl cysteine (NAC) treatment 30 min before or 6 or 10 h after carbon tetrachloride (CCl4) administration significantly prevented the liver necrosis produced by the hepatotoxin at 24 h. NAC pretreatment was able to partially decrease the covalent binding of CCl4 reactive metabolites at 1 and 3 h of poisoning and, to a small extent, the concentration of CCl4 reaching the liver at 3 h. NAC also diminished partially the CCl4-promoted increases in lipid peroxidation at 3 h, but had an enhancing effect of its own of small intensity. Results suggest that early and late protective effects of NAC might be attributable to its prior conversion to cysteine and glutathione.
Assuntos
Acetilcisteína/uso terapêutico , Tetracloreto de Carbono/toxicidade , Fígado/patologia , Necrose/prevenção & controle , Acetilcisteína/farmacologia , Animais , Tetracloreto de Carbono/metabolismo , Peroxidação de Lipídeos/efeitos dos fármacos , Fígado/efeitos dos fármacos , Masculino , Microssomos Hepáticos/efeitos dos fármacos , Microssomos Hepáticos/metabolismo , Necrose/induzido quimicamente , Ratos , Ratos Sprague-DawleyRESUMO
Se estudiaron 15 miembros de una familia con hiperlipidemia familiar combinada, en los que observamos las caracteristicas clinicas principales de este trastorno. El analisis del pedigree y los valores de colesterol y trigilceridos permiten postular un mecanismo de transmision autosomico dominante. El 50 de los individuos de la generacion de los probandos demonstraron valores de lipidos diagnosticos de hiperlipidemia. En base a los valores absolutos de colesterol y trigiceridos, asi como a la electroforesis de lipoproteinas en suero se diagnosticaron los patrones de Fredrickson IIa, IIb, y IV, con una frecuencia similar, de aproximadamente 33% para cada uno de los fenotipos entre los individuos afectados.Los valores medios de colesterol y trigliceridos ajustados para edad y sexo entre los miembros hiperlipidemicos fueron de 308.9 mg/dl (> P95) y 252.1 mg/dl (> P90) respectivamente, mientras que en los casos no afectados correspondieron a 212.1 mg/dl (< P50) para colesterol y 124.9 mg/dl (< P50) para trigliceridos. Se observo claramente en esta familia la existencia de cardiopatia ateroesclerosa prematura, incluyendo 3 casos de muerte a edad temprana por infarto miocardico