RESUMEN
BACKGROUND: Alzheimer's disease (AD) is a progressive neurodegenerative disease associated with cognitive decline and complete loss of basic functions. The ubiquitous apicomplexan parasite Toxoplasma gondii (T. gondii) infects up to one third of the world's population and is implicated in AD. METHODS: We infected C57BL/6 wild-type male and female mice with 10 T. gondii ME49 cysts and assessed whether infection led to behavioral and anatomical effects using immunohistochemistry, immunofluorescence, Western blotting, cell culture assays, as well as an array of mouse behavior tests. RESULTS: We show that T. gondii infection induced two major hallmarks of AD in the brains of C57BL/6 male and female mice: beta-amyloid (Aß) immunoreactivity and hyperphosphorylated Tau. Infected mice showed significant neuronal death, loss of N-methyl-D-aspartate receptor (NMDAR) expression, and loss of olfactory sensory neurons. T. gondii infection also caused anxiety-like behavior, altered recognition of social novelty, altered spatial memory, and reduced olfactory sensitivity. This last finding was exclusive to male mice, as infected females showed intact olfactory sensitivity. CONCLUSIONS: These results demonstrate that T. gondii can induce advanced signs of AD in wild-type mice and that it may induce AD in some individuals with underlying health problems.
Asunto(s)
Enfermedad de Alzheimer/metabolismo , Enfermedad de Alzheimer/parasitología , Receptores de N-Metil-D-Aspartato/metabolismo , Transducción de Señal/fisiología , Toxoplasma , Toxoplasmosis/metabolismo , Enfermedad de Alzheimer/etiología , Animales , Células Cultivadas , Femenino , Masculino , Ratones , Ratones Endogámicos C57BL , Distribución Aleatoria , Toxoplasmosis/complicacionesRESUMEN
BACKGROUND: Non-alcoholic fatty liver disease (NAFLD) is a chronic liver disease afflicting about one third of the world's population and 30 % of the US population. It is induced by consumption of high-lipid diets and is characterized by liver inflammation and subsequent liver pathology. Obesity and consumption of a high-fat diet are known to increase the risk of Alzheimer's disease (AD). Here, we investigated NAFLD-induced liver inflammation in the pathogenesis of AD. METHODS: WT and APP-Tg mice were fed with a standard diet (SD) or a high-fat diet (HFD) for 2, 5 months, or 1 year to induce NAFLD. Another set of APP-Tg mice were removed from HFD after 2 months and put back on SD for 3 months. RESULTS: During acute phase NAFLD, WT and APP-Tg mice developed significant liver inflammation and pathology that coincided with increased numbers of activated microglial cells in the brain, increased inflammatory cytokine profile, and increased expression of toll-like receptors. Chronic NAFLD induced advanced pathological signs of AD in both WT and APP-Tg mice, and also induced neuronal apoptosis. We observed decreased brain expression of low-density lipoprotein receptor-related protein-1 (LRP-1) which is involved in ß-amyloid clearance, in both WT and APP-Tg mice after ongoing administration of the HFD. LRP-1 expression correlated with advanced signs of AD over the course of chronic NAFLD. Removal of mice from HFD during acute NAFLD reversed liver pathology, decreased signs of activated microglial cells and neuro-inflammation, and decreased ß-amyloid plaque load. CONCLUSIONS: Our findings indicate that chronic inflammation induced outside the brain is sufficient to induce neurodegeneration in the absence of genetic predisposition.
Asunto(s)
Enfermedad de Alzheimer/complicaciones , Regulación de la Expresión Génica/fisiología , Enfermedad del Hígado Graso no Alcohólico/complicaciones , Placa Amiloide/patología , Factores de Edad , Enfermedad de Alzheimer/genética , Precursor de Proteína beta-Amiloide/genética , Animales , Apolipoproteínas E/genética , Apolipoproteínas E/metabolismo , Proteínas de Unión al Calcio/metabolismo , Citocinas/genética , Citocinas/metabolismo , Dieta Alta en Grasa/efectos adversos , Modelos Animales de Enfermedad , Grasas/metabolismo , Humanos , Proteína 1 Relacionada con Receptor de Lipoproteína de Baja Densidad , Ratones , Ratones Transgénicos , Proteínas de Microfilamentos/metabolismo , Mutación/genética , Proteínas del Tejido Nervioso/genética , Proteínas del Tejido Nervioso/metabolismo , Infiltración Neutrófila , Enfermedad del Hígado Graso no Alcohólico/etiología , Receptores de LDL/genética , Receptores de LDL/metabolismo , Receptores Toll-Like/metabolismo , Proteínas Supresoras de Tumor/genética , Proteínas Supresoras de Tumor/metabolismoRESUMEN
There are 5 common types of chronic nonhealing lower-extremity wounds: arterial, venous, diabetic foot ulcer, pressure, and mixed or atypical. Each chronic wound type has distinct features, and understanding the underlying cause will dictate the wound treatment plan. Here, the authors review the distinguishing wound properties for these 5 common chronic nonhealing lower-extremity wounds and outline a comprehensive treatment plan that addresses wound perfusion, debridement, infection control, moisture balance, and use of complementary advanced wound care products.