RESUMEN
Strategies aimed at treating atherosclerosis by immunization protocols are emerging. Such protocols commonly use adjuvants as non-specific stimulators of immune responses. However, adjuvants are known to modify various disease processes. The aim of this study was to determine whether adjuvants alter the development of atherosclerosis. We performed immunization protocols in apolipoprotein E knockout mice (E degrees ) following chronic administration schedules commonly employed in experimental atherosclerosis. Our results point out a dramatic effect of several adjuvants on the development of atherosclerosis; three of the four adjuvants tested reduced lesion size. The Alum adjuvant, which is the adjuvant currently used in most vaccination protocols in humans, displayed a strong atheroprotective effect. Mechanisms accounting for atheroprotective effect of Freund's adjuvants included their capacity to increase both Th2 responses and anti-MDA-LDL IgM titers, and/or to impose atheroprotective lipoprotein profiles. The present study indicates that adjuvants have potent atheromodulating capabilities, and thus, implies that the choice of adjuvant is crucial in long-term immunization protocols in experimental atherosclerosis.
Asunto(s)
Adyuvantes Inmunológicos/uso terapéutico , Compuestos de Alumbre/uso terapéutico , Aterosclerosis/tratamiento farmacológico , Adyuvante de Freund/uso terapéutico , Inmunización/métodos , Animales , Anticuerpos Antiidiotipos/inmunología , Apolipoproteínas E/deficiencia , Aterosclerosis/sangre , Aterosclerosis/inmunología , Citocinas/sangre , Modelos Animales de Enfermedad , Estudios de Seguimiento , Cromatografía de Gases y Espectrometría de Masas , Inmunoglobulina G/inmunología , Inmunoglobulina M/inmunología , Masculino , Ratones , Ratones Noqueados , Factores de Tiempo , Resultado del TratamientoRESUMEN
OBJECTIVE: The contribution of thrombosis and coagulation in atherogenesis is largely unknown. We investigated the contribution of the coagulation intrinsic factor VIII (FVIII)-dependent pathway in atherogenesis. METHODS AND RESULTS: Apolipoprotein E and FVIII double-deficient mice (E degrees/FVIII degrees) were generated. Aortic root lesions were analyzed in 14-week-old and 22-week-old female mice maintained for 8 or 16 weeks, respectively, on a normal chow diet or a hypercholesterolemic diet. CONCLUSIONS: Despite a higher plasma total cholesterol concentration compared with E degrees mice, E degrees/FVIII degrees mice developed dramatically less early-stage atherosclerotic lesions. Whereas early lesions in E degrees mice contained abundant fibrin(ogen) deposits on which few platelets adhered, lesions in E degrees/FVIII degrees were almost devoid of fibrin(ogen), and no platelets could be detected. The genotype effect on development and composition of lesions tended to decrease with time. This study demonstrates that the activation of the intrinsic pathway of coagulation is potently proatherogenic at the early stage of atherogenesis.
Asunto(s)
Apolipoproteínas E/genética , Aterosclerosis/fisiopatología , Coagulación Sanguínea/fisiología , Factor VIII/genética , Hemofilia A/fisiopatología , Animales , Apolipoproteínas E/metabolismo , Aterosclerosis/genética , Aterosclerosis/patología , Colesterol/biosíntesis , Colesterol/sangre , Factor VIII/metabolismo , Femenino , Hemofilia A/genética , Hemofilia A/patología , Ratones , Ratones NoqueadosRESUMEN
Gene electrotranfer is an attractive physical method to deliver genes to target tissues. The aim of this study was to evaluate in vivo gene electrotransfer into spleen, one of the most important lymphoid organ, in order to create a new tool to modulate the immuno-inflammatory system. C57Bl/6 mice were submitted either to intramuscular electrotransfer (IME) as a reference method or to intrasplenic (ISE) gene electrotransfer. In the naked injected plasmids, the CMV promoter controlled the expression of luciferase, secreted alkaline phosphatase, EGFP, or IFNgamma. The ISE optimal electrotransfer conditions were first determined and ISE was found to be an efficient gene transfer method, which can be used to express secreted or intracellular proteins transiently. Although transfected cells were still present in the spleen 30 days after ISE, transfected spleen cells could recirculate since they were detected in extrasplenic locations. Using a T-lymphocyte-specific promoter controlling the expression of EGFP, splenic T cells could be targeted. Finally, it appeared that ISE procedure does not impair by itself the immune response and does not result in a significant production of antibodies directed to the transgenic proteins in C57Bl/6 mice. This strategy constitutes a new method to manipulate the immune response that can be used in various experimental designs.
Asunto(s)
Electroporación/métodos , Terapia Genética/métodos , Linfocitos T/metabolismo , Fosfatasa Alcalina/genética , Animales , Ensayo de Inmunoadsorción Enzimática/métodos , Femenino , Expresión Génica , Proteínas Fluorescentes Verdes , Interferón gamma/genética , Luciferasas/genética , Proteínas Luminiscentes/genética , Masculino , Ratones , Ratones Endogámicos C57BL , Músculo Esquelético/metabolismo , TransgenesRESUMEN
BACKGROUND: A chronic immune response involving proinflammatory T helper cell 1 (Th1) lymphocyte activation occurs in the atherosclerotic lesion, but whether this activation is protective or deleterious remains unclear. Methods and Results-- We modulated the immune response of the atherosclerosis-prone apolipoprotein E-deficient (apoE(-/-)) mouse. Eight-week-old apoE(-/-) mice were treated daily with pentoxifylline (PTX), a known inhibitor of the Th1 differentiation pathway, or PBS (control) for 4 weeks or 12 weeks. Twelve-week PTX treatment reduced atherosclerotic lesion size by 60% (P<0.01). PTX-treated mice developed lesions that were limited to the degree of fatty streaks. In contrast, control mice developed mature fibrofatty atherosclerotic lesions. In parallel, the proportion of interferon (IFN)-gamma-producing Th1 splenic lymphocytes was significantly reduced by PTX, and lesion size was correlated to the proportion of IFN-gamma(+) T cells. In vitro addition of PTX to cultured spleen cells did not modify the production of IFN-gamma but increased the production of IL-10 by T cells, indicating that PTX does not suppress IFN-gamma production but rather blocks Th1 polarization while promoting Th2 polarization. CONCLUSIONS: Thus, PTX protected mice from atherosclerosis by reducing the Th1 polarization of T helper lymphocytes. This study demonstrates that the Th1 immune response associated with atherosclerosis is deleterious and that a modulation of the Th1 differentiation pathway may provide a new pharmacological tool to treat this disease.