Antagonism of cysteinyl leukotriene receptors by zafirlukast modulated acute inflammatory reaction in tilapia, Oreochromis niloticus.

To identify activation pathways and effector mechanisms of innate immunity in fish has become relevant for the sanitary management of intensive fish farming. However, little is known about the blocking of cysteinyl leukotrienes receptors (CysLTRs) and their effects in teleost fish. Our study evaluated the anti-inflammatory effect of 250 and 500 µg zafirlukast (antagonist of CysLTRs)/kg b.w., administered orally in the diet, during acute inflammatory reaction induced by Aeromonas hydrophila bacterins in Oreochromis niloticus. 80 tilapia were distributed in 10 aquariums (100L of water each, n = 8) to constitute three treatments: Control (inoculated with A. hydrophila bacterin and untreated); Treated with 250 µg or 500 µg of zafirlukast/kg b.w. and inoculated. To be evaluated in three periods: 6, 24 and 48 h post-inoculation (HPI), totaling nine aquariums. A tenth group was sampled without any stimulus to constitute reference values (Physiological standards). Tilapia treated with zafirlukast demonstrated dose-response effect in the decrease of accumulated inflammatory cells, strongly influenced by granulocytes and macrophages. Zafirlukast treated-tilapia showed decrease in blood leukocyte counts (mainly neutrophils, and monocytes) and reactive oxygen species production. Treatment with zafirlukast resulted in down-regulation of ceruloplasmin, complement 3, alpha2-macroglobulin, transferrin and apolipoprotein A1, as well as up-regulation of haptoglobin. Our study provided convincing results in the pathophysiology of tilapia inflammatory reaction, considering that treatment with zafirlukast, antagonist of cysteinyl leukotriene receptors, resulted in a dose-response effect by suppressing the dynamics between leukocytes in the bloodstream and cell accumulation in the inflamed focus, as well as modulated the leukocyte oxidative burst and the acute phase protein response.

Asthma aggravates alzheimer's disease by up-regulating NF- κB signaling pathway through LTD4.

Clinical studies have shown that asthma is a risk factor for dementia or Alzheimer's disease (AD). To investigate whether asthma aggravates AD in APP/PS1 mice and explore the potential mechanisms, an asthma model was established using six-month-old APP/PS1 mice, and montelukast was used as a therapeutic agent in APP/PS1 mice with asthma. The Morris water maze test showed that asthma aggravates spatial learning and memory abilities. Asthma also upregulates the NF-κB inflammatory pathway in APP/PS1 mice and promotes the expression of beta-site amyloid precursor protein cleaving enzyme 1 (BACE1), amyloid-ß (Aß) deposition, neuronal damage, synaptic plasticity deficiency, activation of microglia and astrocytes. The level of LTD4 and its receptor CysLT1R in the hippocampus of APP/PS1 mice after the asthma modeling was established was higher than that in APP/PS1 mice, suggesting that asthma may affect the pathology of AD through LTD4 and its receptor Cys-LT1R. Montelukast ameliorates these pathological changes and cognitive impairment. These results suggest that asthma aggravates AD pathology and cognitive impairment of APP/PS1 mice via upregulation of the NF-κB inflammatory pathway, and montelukast ameliorates these pathological changes.

Clinical safety of zafirlukast treatment during acute inflammatory reaction in nile tilapia (Oreochromis Niloticus)

Little is known about the toxicity of immune modulators in fish. Zafirlukast is an anti-inflammatory that antagonizes cysteine leukotriene receptors (CysLTR1). Aiming to study immunomodulatory treatments on fish health, this study evaluated the clinical safety of oral zafirlukast treatment, through biochemical and hematological analyzes during acute inflammatory reaction in Nile tilapia (Oreochromis niloticus), induced by Aeromonas hydrophilabacterins. 72 young tilapias were randomly divided in 9 aquariums (100 L each, n=8) to compose the following treatments: T0 (control), T1 (Treatment with 250 μg zafirlukast) and T2 (Treatment with 500 μg zafirlukast). Eight animals were evaluated per treatment in three periods: six, 24 and 48 hours post-inoculation (HPI), blood collection was performed for hematological and serum biochemical evaluation. The study of hepatic and renal functionality revealed that treatment with both doses of zafirlukast did not result in changes in the circulating values of aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase, creatinine, triglycerides, cholesterol, and total protein, suggesting that the drug has not presented hepatotoxicity, as well as compromised liver and kidney functions. Tilapia submitted to treatment with 500 μg showed adverse hematological effects characterizedby polycythemia associated with microcytosis. Therefore, oral treatment with zafirlukast has demonstrated clinical safety at a therapeutic dose of 250 μg in tilapia during acute aerocystitis, although hematological changes were observed in tilapia treatedwith overdose of this leukotriene blocker.

Pouco se sabe sobre a toxicidade de imunomoduladores em peixes. Zafirlukast é um anti-inflamatório que antagoniza os receptores de leucotrienos cisteínicos (CysLTR1). Com o objetivo de estudar o efeito de tratamentos imunomoduladores sobre a saúde dos peixes, este estudo avaliou a segurança clínica do tratamento com zafirlucaste oral, por meio de análises bioquímicas e hematológicas durante reação inflamatória aguda em tilápia do Nilo (Oreochromis niloticus), induzida por bacterinas de Aeromonas hydrophila.Para tal, 72 tilápias jovens foram divididas aleatoriamente em 9 aquários (100 L cada, n=8) para compor os seguintes tratamentos: T0 (controle), T1 (Tratamento com 250 μg de zafirlucaste) e T2 (Tratamento com 500 μg de zafirlucaste). Oito animais foram avaliados por tratamento em três períodos: seis, 24 e 48 horas pós-inoculação (HPI), foi realizada coleta de sangue para avaliação hematológica e bioquímica sérica. O estudo da funcionalidade hepática e renal revelou que o tratamento com ambas as doses de zafirlucaste não resultou em alterações nos valores circulantes de aspartato aminotransferase (AST), alanina aminotransferase (ALT), fosfatase alcalina, creatinina, triglicerídeos, colesterol e proteína total, sugerindo que a droga não comprometeu as funçõeshepáticas e renais. As tilápias tratadas com 500 μg apresentaram efeitos hematológicos adversos caracterizados por policitemia associada a microcitose. Portanto, o tratamento oral com zafirlucaste demonstrou segurança clínica nadose de 250 μg em tilápiasdurante aerocistite aguda, embora alterações hematológicas tenham sido observadas em tilápias tratadas com sobredosagem deste bloqueador de leucotrieno.