RESUMO
Background: Chronic kidney disease (CKD) patients have deficient levels of glutathione peroxidase-3 (GPx3). We hypothesized that GPx3 deficiency may lead to cardiovascular disease in the presence of chronic kidney disease due to an accumulation of reactive oxygen species and decreased microvascular perfusion of the myocardium. Methods. To isolate the exclusive effect of GPx3 deficiency in kidney disease-induced cardiac disease, we studied the GPx3 knockout mouse strain (GPx3-/-) in the setting of surgery-induced CKD. Results. Ribonucleic acid (RNA) microarray screening of non-stimulated GPx3-/- heart tissue show increased expression of genes associated with cardiomyopathy including myh7, plac9, serpine1 and cd74 compared with wild-type (WT) controls. GPx3-/- mice underwent surgically induced renal mass reduction to generate a model of CKD. GPx3-/- + CKD mice underwent echocardiography 4 weeks after injury. Fractional shortening (FS) was decreased to 32.9 ± 5.8% in GPx3-/- + CKD compared to 62.0% ± 10.3 in WT + CKD (P < 0.001). Platelet aggregates were increased in the myocardium of GPx3-/- + CKD. Asymmetric dimethylarginine (ADMA) levels were increased in both GPx3-/- + CKD and WT+ CKD. ADMA stimulated spontaneous platelet aggregation more quickly in washed platelets from GPx3-/-. In vitro platelet aggregation was enhanced in samples from GPx3-/- + CKD. Platelet aggregation in GPx3-/- + CKD samples was mitigated after in vivo administration of ebselen, a glutathione peroxidase mimetic. FS improved in GPx3-/- + CKD mice after ebselen treatment. Conclusion: These results suggest GPx3 deficiency is a substantive contributing factor to the development of kidney disease-induced cardiac disease.
Assuntos
Modelos Animais de Doenças , Glutationa Peroxidase/fisiologia , Cardiopatias/etiologia , Agregação Plaquetária , Insuficiência Renal Crônica/complicações , Trombose/etiologia , Disfunção Ventricular Esquerda/etiologia , Animais , Arginina/análogos & derivados , Arginina/metabolismo , Cardiopatias/metabolismo , Cardiopatias/patologia , Camundongos , Camundongos Knockout , Espécies Reativas de Oxigênio/metabolismo , Insuficiência Renal Crônica/metabolismo , Insuficiência Renal Crônica/patologia , Trombose/metabolismo , Trombose/patologia , Disfunção Ventricular Esquerda/metabolismo , Disfunção Ventricular Esquerda/patologiaRESUMO
Vascular progenitor cells show promise for the treatment of microvasculature endothelial injury. We investigated the function of renal artery progenitor cells derived from radical nephrectomy patients, in animal models of acute ischemic and hyperperfusion injuries. Present in human adventitia, CD34positive/CD105negative cells were clonal and expressed transcription factors Sox2/Oct4 as well as surface markers CXCR4 (CD184)/KDR(CD309) consistent with endothelial progenitor cells. Termed renal artery-derived vascular progenitor cells (RAPC), injected cells were associated with decreased serum creatinine after ischemia/reperfusion, reduced albuminuria after hyperperfusion, and improved blood flow in both models. A small population of RAPC integrated with the renal microvasculature following either experimental injury. At a cellular level, RAPC promoted local endothelial migration in co-culture. Profiling of RAPC microRNA identified high levels of miRNA 218; also found at high levels in exosomes isolated from RAPC conditioned media after cell contact for 24 hours. After hydrogen peroxide-induced endothelial injury, RAPC exosomes harbored Robo-1 transcript; a gene known to be regulated by mir218. Such exosomes enhanced endothelial cell migration in culture in the absence of RAPC. Thus, our work shows the feasibility of pre-emptive pro-angiogenic progenitor cell procurement from a targeted patient population and potential therapeutic use in the form of autologous cell transplantation.
Assuntos
Injúria Renal Aguda/terapia , Capilares/fisiologia , Rim/patologia , Transplante de Células-Tronco/métodos , Células-Tronco/metabolismo , Cicatrização , Injúria Renal Aguda/induzido quimicamente , Animais , Antígenos CD34/metabolismo , Capilares/patologia , Movimento Celular , Técnicas de Cocultura , Creatinina/sangue , Modelos Animais de Doenças , Endoglina/metabolismo , Endotélio/citologia , Exossomos/metabolismo , Estudos de Viabilidade , Humanos , Peróxido de Hidrogênio/toxicidade , Rim/irrigação sanguínea , Camundongos , MicroRNAs/metabolismo , Proteínas do Tecido Nervoso/metabolismo , Receptores CXCR4/metabolismo , Receptores Imunológicos/metabolismo , Artéria Renal/citologia , Transplante Autólogo/métodos , Receptor 2 de Fatores de Crescimento do Endotélio Vascular/metabolismo , Proteínas RoundaboutRESUMO
Vascular inflammation is a major contributor to the severity of acute kidney injury. In the context of vasospasm-independent reperfusion injury we studied the potential anti-inflammatory role of the Gα-related RGS protein, RGS4. Transgenic RGS4 mice were resistant to 25 min injury, although post-ischemic renal arteriolar diameter was equal to the wild type early after injury. A 10 min unilateral injury was performed to study reperfusion without vasospasm. Eighteen hours after injury, blood flow was decreased in the inner cortex of wild-type mice with preservation of tubular architecture. Angiotensin II levels in the kidneys of wild-type and transgenic mice were elevated in a sub-vasoconstrictive range 12 and 18 h after injury. Angiotensin II stimulated pre-glomerular vascular smooth muscle cells (VSMCs) to secrete the macrophage chemoattractant RANTES, a process decreased by angiotensin II R2 (AT2) inhibition. However, RANTES increased when RGS4 expression was suppressed implicating Gα protein activation in an AT2-RGS4-dependent pathway. RGS4 function, specific to VSMC, was tested in a conditional VSMC-specific RGS4 knockout showing high macrophage density by T2 MRI compared with transgenic and non-transgenic mice after the 10 min injury. Arteriolar diameter of this knockout was unchanged at successive time points after injury. Thus, RGS4 expression, specific to renal VSMC, inhibits angiotensin II-mediated cytokine signaling and macrophage recruitment during reperfusion, distinct from vasomotor regulation.