Dietary Supplementation with Omega-3-PUFA-Rich Fish Oil Reduces Signs of Food Allergy in Ovalbumin-Sensitized Mice

We investigated the effect of dietary supplementation with n-3 PUFA (fish oil source) in an experimental model of food allergy. Mice were sensitized (allergic group) or not (nonallergic group) with OVA and were fed with OVA diet to induce allergy signals. Mice were fed with regular diet in which 7% of lipid content was provided by soybean (5% of n-3 PUFA) or fish (25% of n-3 PUFA) oil. Allergic group mice had increased serum levels of antiovalbumin IgE and IgG1 and changes in small intestine, characterized by an increased edema, number of rolling leukocytes in microcirculation, eosinophil infiltration, mucus production, and Paneth cell degranulation, in comparison to non-allergic group. All these inflammatory parameters were reduced in mice fed high-n-3-PUFA diet. Our data together suggest that diet supplementation with n-3 PUFA from fish oil may consist of a valid adjuvant in food allergy treatment

A sinalização parácrina por ATP/ADP é detrimental durante a morte celular estéril induzida por paracetamol

Exportado OPUSMade available in DSpace on 2019-08-12T20:12:13Z (GMT). No. of bitstreams: 2 disserta__o.pdf: 1963344 bytes, checksum: 547bd069be7b7566a67b60d5354ee511 (MD5) capa.pdf: 64471 bytes, checksum: 70e278ca325c718013da16e53ce3115d (MD5) Previous issue date: 1O fígado é essencial para a manutenção da homeostase corporal. Dentre seus diversos papéis críticos, uma função especialmente importante é o metabolismo hepático de produtos químicos, toxinas e drogas. Considerando as importantes funções desempenhadas pelo fígado, é de se esperar que as falências hepáticas acarretem grandes prejuízos aos indivíduos sendo, dessa forma, importante ampliar os conhecimentos neste campo. A overdose por paracetamol (APAP) causa injúria no fígado e é a principal causa de falência hepática aguda (FHA) nos Estados Unidos e no Reino Unido. Já é conhecido que durante a morte celular induzida por APAP há um desbalanço na dinâmica iônica celular (especialmente mitocondrial), que inclui a desregulação no conteúdo intracelular de cálcio. Tal alteração pode, em última análise, promover a morte da célula por necrose, com conseqüente liberação de conteúdo celular, como por exemplo DNA, HSP (proteínas de choque térmico Heat Shock Protein), produtos mitocondriais e ATP. De maneira interessante, o ATP é capaz de induzir pulsos de cálcio em hepatócitos em cultura, porém, ainda não é determinado como a sinalização purinérgica e a sinalização de cálcio relacionam-se neste contexto, bem como seu papel isolado no processo de morte celular estéril induzida por paracetamol. Assim, nosso trabalho investigou se a liberação extracelular de ATP durante a necrose induzida por APAP poderia ser um fator reverberador de morte celular, bem como estudamos os mecanismos pelos quais purinas poderiam modular o ciclo de vida de hepatócitos. Demonstramos que a incubação de uma linhagem hepatocítica (HepG2) com paracetamol promove morte celular, com aumento da concentração de ATP no meio de cultura, e conseqüente hiper-responsividade a essa purina. De maneira interessante, a destruição do ATP por uma ATPase reverteu significativamente a morte celular induzida por APAP, inclusive em um modelo in vivo de FHA. Ainda, a incubação com ATP e ADP, mas não com adenosina, foi capaz de induzir diretamente morte celular. Finalmente, demonstramos que a incubação com adenosina, similar ao observado com ATPase, reverteu a morte celular induzida por APAP. Nossos dados nos permitem concluir que a liberação de ATP (e seu metabolismo aADP) é detrimental durante a morte celular aguda, e que o metabolismo final do ATP até a adenosina pode ser um mecanismo protetor contra a reverberação da morte celular aguda.The liver is an essential organ to maintaining the body homeostasis. Among its many critical roles, resides the important function of hepatic metabolism of chemicals, toxins and drugs. Considering the important functions performed by the liver, it is expected that the hepatic diseases entail large losses to illness people. It is therefore important to amplify the knowledge on this field. Paracetamol (APAP) overdose causes liver injury and is the major cause of acute liver failure (ALF) in the United States and UK. It is well known that during the acute cell death, such as induced by APAP, an imbalance in the ionic cell dynamics is observed (especially in mitochondria), which includes the dysregulation in the intracellular calcium content. Such alteration can, ultimately, promote cell death by necrosis, releasing intracellular contents, including DNA, HSP, mitochondrial products and ATP. Interesting, ATP induces calcium pulses in cultured hepatocytes, although it is not determined how the purinergic signaling and the calcium signaling are co-related in the context of necrosis, as well as its individual role in the sterile cell death mechanism induced by paracetamol. In this context, we have investigated if the extracellular ATP release during APAP-induced necrosis consists in a reverberating cell death feature, as well to elucidate the mechanisms by which purines modulate hepatocyte mitosis cycle. We have shown that the incubation of a hepatocytic linage (HepG2) with paracetamol promotes cellular death, increasing ATP concentration in the culture medium, and consequently the hyper-responsiveness to this purine. Interesting, the ATP destruction (by an ATPase) reverted significantly the cell death induced by APAP, also by using a in vivo model of ALF. Thus, the incubation with adenosine reverted the cell death induced by APAP. Our data suggest that the ATP release (and its metabolite ADP) is detrimental during the acute cell death and the final metabolism of ATP until adenosine may be a protective mechanism against the acute cell death amplification, putting forward the future exploration of this signaling pathway in the therapeutics

Pathophysiological Relevance of Neutrophils in Acetaminophen Hepatotoxicity Reply

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Intravital microscopy: Taking a close look inside the living organisms

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Murine model to study brain, behavior and immunity during hepatic encephalopathy

AIM: To propose an alternative model of hepatic encephalopathy (HE) in mice, resembling the human features of the disease. METHODS: Mice received two consecutive intraperitoneal injections of thioacetamide (TAA) at low dosage (300 mg/kg). Liver injury was assessed by serum transaminase levels (ALT) and liver histology (hematoxylin and eosin). Neutrophil infiltration was estimated by confocal liver intravital microscopy. Coagulopathy was evaluated using prolonged prothrombin and partial thromboplastin time. Hemodynamic parameters were measured through tail cuff. Ammonia levels were quantified in serum and brain samples. Electroencephalography (EEG) and psychomotor activity score were performed to show brain function. Brain edema was evaluated using magnetic resonance imaging. RESULTS: Mice submitted to the TAA regime developed massive liver injury, as shown by elevation of serum ALT levels and a high degree of liver necrosis. An intense hepatic neutrophil accumulation occurred in response to TAA-induced liver injury. This led to mice mortality and weight loss, which was associated with severe coagulopathy. Furthermore, TAA-treated mice presented with increased serum and cerebral levels of ammonia, in parallel with alterations in EEG spectrum and discrete brain edema, as shown by magnetic resonance imaging. In agreement with this, neuropsychomotor abnormalities ensued 36 h after TAA, fulfilling several HE features observed in humans. In this context of liver injury and neurological dysfunction, we observed lung inflammation and alterations in blood pressure and heart rate that were indicative of multiple organ dysfunction syndrome. CONCLUSION: In summary, we describe a new murine model of hepatic encephalopathy comprising multiple features of the disease in humans, which may provide new insights for treatment.status: publishe