RESUMEN
BACKGROUND: Cyclosporine (CsA) has significantly improved long-term survival after organ transplantations. Hypertension and nephrotoxicity are common side effects during CsA treatment and are aggravated by high salt intake. OBJECTIVE: To examine whether lipoic acid (LA), a natural antioxidant that scavenges reactive oxygen species and regenerates/recycles endogenous antioxidants, could prevent CsA-induced hypertension and nephrotoxicity. METHODS: Six-week-old spontaneously hypertensive rats (SHR) on a high-sodium diet (NaCl 6%) received CsA [5 mg/kg subcutaneously (s.c.)] alone or in combination with LA (0.5% w/w) for 6 weeks. Blood pressure, arterial functions, and tissue morphology were determined. Immunohistochemistry, quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) and high-pressure liquid chromatography were used for kidney and heart samples. RESULTS: CsA induced severe hypertension, cardiac hypertrophy, endothelial dysfunction, and pronounced albuminuria. Histologically, the kidneys showed severe thickening of the media of the afferent arteries with fibrinoid necrosis, perivascular monocyte/macrophage infiltration and nitrotyrosine overexpression. CsA induced the expression of fibrogenic connective tissue growth factor both in the heart and kidneys. The detrimental effects of CsA were associated with upregulation of myocardial atrial natriuretic peptide (ANP) mRNA expression, paradoxical activation of the renin-angiotensin system (RAS), induction of renal reduced nicotinamide-adenine dinucleotide phosphate (NADPH) oxidase, and overexpression of oxidative stress-induced transcription factor NRF2. LA lowered blood pressure, ameliorated cardiac hypertrophy and endothelial dysfunction, and totally normalized albuminuria. In LA-treated rats, renal and cardiac morphologies were indistinguishable from those of SHR controls. CsA-induced myocardial ANP and connective tissue growth factor (CTGF) mRNA overexpression, RAS activation, NADPH oxidase induction, and NRF2 overexpression were prevented by LA. LA induced the mRNA expression of gamma-glutamylcysteine ligase, the rate-limiting enzyme in glutathione synthesis, and markedly increased hepatic cysteine and glutathione concentrations. CONCLUSIONS: Our findings suggest a salutary role for lipoic acid supplementation in the prevention of CsA-induced hypertension and nephrotoxicity, and underscore the importance of increased oxidative stress in the pathogenesis of CsA toxicity.
Asunto(s)
Antioxidantes/efectos adversos , Ciclosporina/efectos adversos , Hipertensión/prevención & control , Enfermedades Renales/prevención & control , Ácido Tióctico/farmacología , Animales , Presión Sanguínea/efectos de los fármacos , Hipertensión/inducido químicamente , Enfermedades Renales/inducido químicamente , Enfermedades Renales/patología , Masculino , Ratas , Ratas Endogámicas SHRRESUMEN
OBJECTIVE: Serine-threonine protein kinase glycogen synthase kinase (GSK)-3 is involved in regulation of many cell functions, but its role in regulation of inflammatory response is unknown. Here we investigate the effects of GSK-3beta inhibition on organ injury/dysfunction caused by lipopolysaccharide or coadministration of lipopolysaccharide and peptidoglycan in the rat. DESIGN: Prospective, randomized study. SETTING: University-based research laboratory. SUBJECTS: Ninety-nine anesthetized male Wistar rats. INTERVENTIONS: Study 1: Rats received either intravenous Escherichia coli lipopolysaccharide (6 mg/kg) or vehicle (1 mL/kg; saline). Study 2: Rats received either intravenous E. coli lipopolysaccharide (1 mg/kg) and Staphylococcus aureus peptidoglycan (0.3 mg/kg) or vehicle. The potent and selective GSK-3beta inhibitors TDZD-8 (1 mg/kg intravenously), SB216763 (0.6 mg/kg intravenously), and SB415286 (1 mg/kg intravenously) or vehicle (10% dimethyl sulfoxide) was administered 30 mins before lipopolysaccharide or lipopolysaccharide and peptidoglycan. MEASUREMENTS AND MAIN RESULTS: Endotoxemia resulted in increases in the serum levels of creatinine (indicator of renal dysfunction), aspartate aminotransferase, alanine aminotransferase (markers for hepatocellular injury), lipase (indicator of pancreatic injury), and creatine kinase (indicator of neuromuscular injury). Coadministration of lipopolysaccharide and peptidoglycan resulted in hepatocellular injury and renal dysfunction. All GSK-3beta inhibitors attenuated the organ injury/dysfunction caused by lipopolysaccharide or lipopolysaccharide and peptidoglycan. GSK-3beta inhibition reduced the Ser536 phosphorylation of nuclear factor-kappaB subunit p65 and the messenger RNA expression of nuclear factor-kappaB-dependent proinflammatory mediators but had no effect on the nuclear factor-kappaB/DNA binding activity in the lung. GSK-3beta inhibition reduced the increase in nuclear factor-kappaB p65 activity caused by interleukin-1 in human embryonic kidney cells in vitro. CONCLUSIONS: The potent and selective GSK-3beta inhibitors TDZD-8, SB216763, and SB415286 reduced the organ injury/dysfunction caused by lipopolysaccharide or lipopolysaccharide and peptidoglycan in the rat. We propose that GSK-3beta inhibition may be useful in the therapy of the organ injury/dysfunction associated with sepsis, shock, and other diseases associated with local or systemic inflammation.
Asunto(s)
Endotoxemia/tratamiento farmacológico , Glucógeno Sintasa Quinasa 3/antagonistas & inhibidores , Tiadiazoles/uso terapéutico , Alanina Transaminasa/sangre , Aminofenoles/administración & dosificación , Animales , Aspartato Aminotransferasas/sangre , Western Blotting , Células Cultivadas , Creatina Quinasa/sangre , Creatinina/sangre , Endotoxemia/inducido químicamente , Glucógeno Sintasa Quinasa 3 beta , Indoles/administración & dosificación , Indoles/uso terapéutico , Enfermedades Renales/inducido químicamente , Lipasa/sangre , Lipopolisacáridos/administración & dosificación , Hígado/patología , Masculino , Maleimidas/administración & dosificación , Maleimidas/uso terapéutico , FN-kappa B/metabolismo , Peptidoglicano/administración & dosificación , Fosforilación , Polisacáridos Bacterianos/administración & dosificación , Estudios Prospectivos , Distribución Aleatoria , Ratas , Ratas Wistar , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Tiadiazoles/administración & dosificaciónRESUMEN
OBJECTIVES AND DESIGN: Magnesium deficiency promotes vasoconstriction and myocardial damage. Recent studies provide evidence that Ang II mobilizes intracellular Mg through AT1 receptor-mediated pathways. We tested the hypothesis of whether magnesium supplementation prevents Ang II-induced myocardial damage and induction of the profibrotic connective tissue growth factor (CTGF). METHODS: Four-week-old double transgenic rats harboring human renin and angiotensinogen genes (dTGR) were given dietary magnesium supplementation (0.6%) for 3 weeks. Control dTGR and normotensive Sprague-Dawley (SD) rats received normal diet (Mg 0.2%). Histopathological, immunohistochemical and mRNA analysis were used to detect the treatment-related effects of dietary magnesium in dTGR. RESULTS: Magnesium (Mg) supplementation decreased blood pressure, ameliorated cardiac hypertrophy, protected against the development of Ang II-induced myocardial damage and increased serum ionized Mg2+ concentration (all variables P < 0.05). There was no difference in serum ionized Mg2+ concentration between dTGR and SD rats. Myocardial connective tissue growth factor (CTGF) mRNA and protein expressions were increased by 300% in dTGR (P < 0.05), especially in areas with myocardial infarctions and vascular inflammation. Magnesium supplementation prevented Ang II-induced myocardial CTGF overexpression (P < 0.05). Magnesium supplementation also improved the therapeutic effects of the calcineurin inhibitor tacrolimus, which produced marked hypomagnesemia when given as monotherapy. CONCLUSION: Our findings suggest a salutary effect for magnesium supplementation in the treatment of Ang II-induced myocardial complications.
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Angiotensina II/farmacología , Suplementos Dietéticos , Proteínas Inmediatas-Precoces/metabolismo , Péptidos y Proteínas de Señalización Intercelular/metabolismo , Magnesio/administración & dosificación , Miocardio/patología , Angiotensinógeno/genética , Animales , Animales Modificados Genéticamente , Presión Sanguínea/efectos de los fármacos , Cardiomegalia/terapia , Factor de Crecimiento del Tejido Conjuntivo , Fibrosis/prevención & control , Humanos , Proteínas Inmediatas-Precoces/efectos de los fármacos , Inmunosupresores/uso terapéutico , Magnesio/sangre , Magnesio/metabolismo , Masculino , ARN Mensajero/genética , ARN Mensajero/metabolismo , Ratas , Ratas Sprague-Dawley , Renina/genética , Tacrolimus/uso terapéuticoRESUMEN
Hypertension is a major risk factor for atherosclerosis. We tested the hypothesis whether high salt intake aggravates endothelial dysfunction and promotes atherosclerosis in apolipoprotein E-deficient mice (ApoE(-)/(-) mice) and their littermate controls (C57Bl/6 mice). The role of increased oxidative stress was also examined. A high-salt diet (NaCl 7%) for 12 weeks increased blood pressure and induced cardiac hypertrophy and albuminuria more pronouncedly in ApoE(-)/(-) mice compared with C57Bl/6. Endothelium-dependent vascular relaxation in response to acetylcholine was almost maximally impaired in ApoE(-)/(-) mice during a normal sodium diet. A high-salt diet did not further impair NO-mediated vascular relaxation. A high-salt diet also markedly attenuated endothelium-dependent relaxation in C57Bl/6 mice. Preincubation with the superoxide scavenger Tiron normalized endothelial function almost completely in both mice strains indicating the central role of increased oxidative stress in the pathogenesis. Aortic superoxide production and the extent of atherosclerotic lesions were greater in ApoE(-)/(-) mice on a normal-salt diet compared with C57Bl/6. The high-salt diet increased vascular superoxide formation and promoted atherosclerosis in ApoE(-)/(-) mice. Changes in dietary salt intake did not influence serum lipids in either mouse strains. Our findings suggest a detrimental role for high salt intake in the development of atherosclerosis and underscore the importance of increased oxidative stress in the pathogenesis salt-induced vascular damage.
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Apolipoproteínas E/deficiencia , Arteriosclerosis/inducido químicamente , Arteriosclerosis/metabolismo , Sodio en la Dieta/toxicidad , Superóxidos/metabolismo , Albuminuria/inducido químicamente , Animales , Apolipoproteínas E/metabolismo , Presión Sanguínea/efectos de los fármacos , Peso Corporal/efectos de los fármacos , Cardiomegalia/inducido químicamente , Masculino , Ratones , Ratones Endogámicos C57BL , Estrés Oxidativo , Sodio en la Dieta/administración & dosificaciónRESUMEN
The present study examined the role of cyclooxygenase-synthetized prostanoids in the pathogenesis of angiotensin-II-induced inflammatory response and vascular injury in transgenic rats harboring mouse renin-2 gene (mREN2 rats). Five- to six-week-old, heterozygous mREN2 rats received the following drug regimens for 8 weeks: (1) controls; (2) cyclooxygenase-2 inhibitor (MF-tricyclic [3-(3,4-difluorophenyl)-4-(4-(methylsulfonyl) phenyl)-2(5H)-furanone], 14 mg kg(-1) p.o.); (3) cyclooxygenase-1/cyclooxygenase-2 inhibitor (sulindac, 14 mg kg(-1) p.o.); (4) angiotensin II receptor antagonist (losartan 40 mg kg(-1) p.o.); (5) MF-tricyclic + losartan; (6) sulindac + losartan. Normotensive Sprague-Dawley rats served as controls. mREN2 rats developed pronounced hypertension, cardiac hypertrophy, and albuminuria as compared to normotensive Sprague-Dawley controls. mREN2 rats showed pronounced perivascular inflammation and morphological damage in the kidneys and the heart. Both MF-tricyclic and sulindac further increased blood pressure and albuminuria in mREN2 rats. Neither MF-tricyclic nor sulindac were able to prevent angiotensin-II-induced perivascular inflammation and morphological changes in the heart or in the kidneys. Myocardial and renal cyclooxygenase-2 mRNA expressions were decreased in mREN2 rats, whereas no difference was found in cyclooxygenase-1 mRNA expressions. Sulindac increased both cyclooxygenase-1 and cyclooxygenase-2 gene expressions, whereas MF-tricyclic increased only cyclooxygenase-2 gene expressions. Losartan normalized blood pressure, cardiac hypertrophy, albuminuria, inflammatory response and morphological changes in mREN2 rats, both in the presence and absence of cyclooxygenase inhibitors. Our findings indicate that cyclooxygenase does not play a central role in the pathogenesis of angiotensin-II-induced inflammatory response and vascular injury in mREN2 rats.
Asunto(s)
Sistema Cardiovascular/efectos de los fármacos , Inhibidores de la Ciclooxigenasa/farmacología , Riñón/efectos de los fármacos , Renina/genética , Albuminuria/inducido químicamente , Albuminuria/prevención & control , Angiotensina II/farmacología , Animales , Animales Modificados Genéticamente , Antihipertensivos/farmacología , Presión Sanguínea/efectos de los fármacos , Peso Corporal/efectos de los fármacos , Cardiomegalia/inducido químicamente , Cardiomegalia/prevención & control , Sistema Cardiovascular/enzimología , Sistema Cardiovascular/patología , Ciclooxigenasa 1 , Ciclooxigenasa 2 , Inhibidores de la Ciclooxigenasa 2 , Ingestión de Alimentos/efectos de los fármacos , Furanos/farmacología , Regulación Enzimológica de la Expresión Génica/efectos de los fármacos , Isoenzimas/efectos de los fármacos , Isoenzimas/genética , Isoenzimas/metabolismo , Riñón/enzimología , Riñón/patología , Losartán/farmacología , Masculino , Proteínas de la Membrana , Ratones , Prostaglandina-Endoperóxido Sintasas/efectos de los fármacos , Prostaglandina-Endoperóxido Sintasas/genética , Prostaglandina-Endoperóxido Sintasas/metabolismo , ARN Mensajero/efectos de los fármacos , ARN Mensajero/genética , ARN Mensajero/metabolismo , Ratas , Ratas Sprague-Dawley , Renina/fisiología , Sulindac/farmacología , Micción/efectos de los fármacosRESUMEN
Dihydropyridines can inhibit gene expression in-vitro and may have a protective vascular effect independent of blood pressure reduction. We tested the hypothesis that lacidipine prevents induction of inducible NO synthase (iNOS), influences leukocyte adhesion and infiltration, inhibits nuclear factor (NF)-kappaB transcription factor activity, and ameliorates end-organ damage in a transgenic rat model of angiotensin (Ang) II--dependent organ sclerosis. We treated rats transgenic for human renin and angiotensinogen (dTGR) from week 4 to 7 with lacidipine (0.3 or 3 mg/kg by gavage). Blood pressure was measured by tail cuff. Organ damage was assessed by histology and immunohistochemistry. Adhesion molecules and cytokines were analyzed by immunohistochemistry. Transcription factors were analyzed by mobility shift assays. Untreated dTGR developed moderate hypertension, cardiac hypertrophy, and severe renal damage with albuminuria. Lacidipine decreased blood pressure slightly at the low dose and substantially at the higher dose. However, both treatments reduced albuminuria and plasma creatinine to the same degree (P<0.05). Intercellular adhesion molecule-1 (ICAM-1) was markedly reduced by lacidipine as well as renal neutrophil and monocyte infiltration. Lacidipine reduced mitogen-activated protein (MAP) kinase phosphorylation and iNOS expression in both cortex and medulla. NF-kappaB and AP-1 were activated in dTGR but reduced by lacidipine. Lacidipine ameliorates Ang II-induced end-organ damage independent of blood pressure lowering, perhaps by inhibiting the MAP kinase pathway and NF-kappaB activation.