RESUMEN
Sickle cell disease (SCD) is characterized by reperfusion injury and chronic oxidative stress. Oxidative stress and hemolysis in SCD result in inactivation of nitric oxide (NO) and depleted arginine levels. We hypothesized that augmenting NO production by arginine supplementation will reduce oxidative stress in SCD. To this end, we measured the effect of arginine (5% in mouse chow) on NO metabolites (NOx), lipid peroxidation (LPO), and selected antioxidants in transgenic sickle mouse models. Untreated transgenic sickle (NY1DD) mice (expressing approximately 75% beta(S)-globin of all beta-globins; mild pathology) and knockout sickle (BERK) mice (expressing exclusively hemoglobin S; severe pathology) showed reduced NOx levels and significant increases in the liver LPO compared with C57BL mice, with BERK mice showing maximal LPO increase in accordance with the disease severity. This was accompanied by reduced activity of antioxidants (glutathione, total superoxide dismutase, catalase, and glutathione peroxidase). However, GSH levels in BERK were higher than in NY1DD mice, indicating a protective response to greater oxidative stress. Importantly, dietary arginine significantly increased NOx levels, reduced LPO, and increased antioxidants in both sickle mouse models. In contrast, nitro-L-arginine methylester, a potent nonselective NOS inhibitor, worsened the oxidative stress in NY1DD mice. Thus, the attenuating effect of arginine on oxidative stress in SCD mice suggests its potential application in the management of this disease.
Asunto(s)
Anemia de Células Falciformes/metabolismo , Arginina/farmacología , Estrés Oxidativo/efectos de los fármacos , Anemia de Células Falciformes/sangre , Anemia de Células Falciformes/patología , Animales , Antioxidantes/metabolismo , Catalasa/metabolismo , Suplementos Dietéticos , Modelos Animales de Enfermedad , Glutatión/metabolismo , Glutatión Peroxidasa/metabolismo , Peroxidación de Lípido/efectos de los fármacos , Ratones , Ratones Endogámicos C57BL , Ratones Transgénicos , NG-Nitroarginina Metil Éster/farmacología , Óxido Nítrico/sangre , Superóxido Dismutasa/metabolismoRESUMEN
OBJECTIVE: Clinically, the vascular pathobiology of human sickle cell disease includes an abnormal state of chronic inflammation and activation of the coagulation system. Since these biologies likely underlie development of vascular disease in sickle subjects, they offer attractive targets for novel therapeutics. Similar findings characterize the sickle transgenic mouse, which therefore provides a clinically relevant inflammation model. METHOD: The authors tested two polyhydroxyphenyl hydroxamic acid derivatives, didox and trimidox, in sickle transgenic mice. Animals were examined by intravital microscopy (cremaster muscle and dorsal skin fold preparations) and by histochemistry before and after transient exposure to hypoxia, with versus without preadministration of study drug. Previous studies have validated the application of hypoxia/reoxygenation to sickle transgenic mice as a disease-relevant model. RESULTS: Animals pretreated with these agents exhibited marked improvements in leukocyte/ endothelial interaction, hemodynamics and vascular stasis, and endothelial tissue factor expression. Thus, these drugs unexpectedly exert powerful inhibition on both the inflammation and coagulation systems. CONCLUSIONS: Each of these changes is expected to be therapeutically beneficial in systemic inflammatory disease in general, and in sickle disease in particular. Thus, these novel compounds offer the advantage of having multiple therapeutic benefits in a single agent.
Asunto(s)
Anemia de Células Falciformes/tratamiento farmacológico , Benzamidinas/administración & dosificación , Inhibidores Enzimáticos/administración & dosificación , Ácidos Hidroxámicos/administración & dosificación , Anemia de Células Falciformes/genética , Anemia de Células Falciformes/metabolismo , Animales , Coagulación Sanguínea/efectos de los fármacos , Coagulación Sanguínea/genética , Comunicación Celular/efectos de los fármacos , Enfermedad Crónica , Modelos Animales de Enfermedad , Evaluación Preclínica de Medicamentos , Células Endoteliales/metabolismo , Humanos , Inflamación/tratamiento farmacológico , Inflamación/genética , Inflamación/metabolismo , Leucocitos/metabolismo , Ratones , Ratones Transgénicos , Tromboplastina/biosíntesisRESUMEN
NF-kappaB is a central transcriptional factor and a pleiotropic regulator of many genes involved in immunological responses. During the screening of a plant extract library of traditional Chinese herbal medicines, we found that NF-kappaB activity was potently inhibited by andrographolide (Andro), an abundant component of the plant Andrographis that has been commonly used as a folk remedy for alleviation of inflammatory disorders in Asia for millennia. Mechanistically, it formed a covalent adduct with reduced cysteine (62) of p50, thus blocking the binding of NF-kappaB oligonucleotide to nuclear proteins. Andro suppressed the activation of NF-kappaB in stimulated endothelial cells, which reduced the expression of cell adhesion molecule E-selectin and prevented E-selectin-mediated leukocyte adhesion under flow. It also abrogated the cytokine- and endotoxin-induced peritoneal deposition of neutrophils, attenuated septic shock, and prevented allergic lung inflammation in vivo. Notably, it had no suppressive effect on IkappaBalpha degradation, p50 and p65 nuclear translocation, or cell growth rates. Our results thus reveal a unique pharmacological mechanism of Andro's protective anti-inflammatory actions.