BDE-99 (2,2',4,4',5 - pentain polybrominated diphenyl ether) induces toxic effects in Oreochromis niloticus after sub-chronic and oral exposure.

PBDEs are toxic, lipophilic, hydrophobic, and persistent artificial chemicals, characterized by high physical and chemical stability. Although PBDEs are known to disturb hormone signaling, many effects of 2,2',4,4',5 - pentain polybrominated diphenyl ethers (BDE-99) in fish remain unclear. The current study investigates the effects of BDE-99 in Oreochromis niloticus where sixty-four juvenile fish were orally exposed to 0.294, 2.94, 29.4 ng g-1 of BDE-99, every 10 days, during 80 days. The results showed histopathological findings in liver and kidney, increasing acetylcholinesterase activity in muscle, disturbs in the antioxidant system in liver and brain and decreasing the plasmatic levels of vitellogenin in females. According to multivariate analysis (IBR), the higher doses are related to the interaction of oxidative and non-oxidative enzymes. The present study provided evidence of deleterious effects after sub-chronic exposure of BDE 99 to O. niloticus, increasing the knowledge about its risk of exposure in fish.

Phytochemicals and Biological Activities of Burdock (Arctium lappa L.) Extracts: A Review.

Arctium lappa L., also known as burdock, is an edible wild plant which has the ability to grow in distinct environments and is considered a weed in several parts of the world. This species has great value in the biological and medical fields with its major secondary components being phenolic compounds and terpenes, substances rich in desired biological activities as antioxidant, antimicrobial, antitumor and anti-inflammatory. In addition, burdock leaves extracts have shown a modulatory effect on the complement system, which plays an important role in the development of inflammatory diseases, with an inhibitory effect on all complement pathways. Thus, natural products with those relevant activities are promising agents for healthcare applications. Therefore, the species A. lappa may represent an interesting asset for researching and developing new therapies for inflammatory afflictions.

Advances in the complement system of a teleost fish, Oreochromisniloticus.

As the earliest known vertebrate possessing a complete immune system, teleost fish played an important role in the evolution of this system. The complement system is an ancient defense mechanism present in invertebrates and vertebrates. In teleost fish the complement system is formed by more than 35 circulating proteins, or found at the cell surface. This system is activated by three pathways: alternative, classical and lectin, generating functions such as the opsonization, lysis and modulation of the innate and adaptive immune responses. The complement system is an important immunological indicator that can be used to study and monitor the effects of environmental, nutritional, and infectious processes. The Nile tilapia (Oreochromis niloticus) is a teleost fish of great economic interest due to its characteristics of easy cultivation, high growth rates, and tolerance to adverse environmental conditions. In addition, Nile tilapia is an excellent model for ecotoxicological studies, however, there are very few studies reporting the performance of the complement system in this species after exposure to environmental pollutants. The aim of this review is to gather recent studies with to address the molecular and functional characterizations of the complement system in Nile tilapia and provide new insights about this defense mechanism. Looking to the future, we believe that the complement system analysis in Tilapia can be used as a biomarker of water quality and the general health status of fish.

Complement System in Alcohol-Associated Liver Disease.

Innate immunity contributes effectively to the development of Alcohol-Associated liver disease (ALD). Particularly, human studies and murine models of ALD have shown that Complement activation plays an important role during the initial and later stages of ALD. The Complement System may contribute to the pathogenesis of this disease since it has been shown that ethanol-derived metabolic products activate the Complement cascade on liver membranes, leading to hepatocellular damage. However, studies evaluating the plasma levels of Complement proteins in ALD patients present contradictory results in some cases, and do not establish a well-marked role for each Complement component. The impairment of leukocyte chemoattractant activity observed in these patients may contribute to the susceptibility to bacterial infections in the latter stages of the disease. On the other hand, murine models of ALD have provided more detailed insights into the mechanisms that link the Complement System to the pathogenesis of the disease. It has been observed that Classical pathway can be activated via C1q binding to apoptotic cells in the liver and contributes to the development of hepatic inflammation. C3 contributes to the accumulation of triglycerides in the liver and in adipose tissue, while C5 seems to be involved with inflammation and liver injury after chronic ethanol consumption. In this review, we present a compendium of studies evaluating the role of Complement in human and murine models of ALD. We also discuss potential therapies to human ALD, highlighting the use of Complement inhibitors.

A double edged-sword - The Complement System during SARS-CoV-2 infection.

In the past 20 years, infections caused by coronaviruses SARS-CoV, MERS-CoV and SARS-CoV-2 have posed a threat to public health since they may cause severe acute respiratory syndrome (SARS) in humans. The Complement System is activated during viral infection, being a central protagonist of innate and acquired immunity. Here, we report some interactions between these three coronaviruses and the Complement System, highlighting the central role of C3 with the severity of these infections. Although it can be protective, its role during coronavirus infections seems to be contradictory. For example, during SARS-CoV-2 infection, Complement System can control the viral infection in asymptomatic or mild cases; however, it can also intensify local and systemic damage in some of severe COVID-19 patients, due to its potent proinflammatory effect. In this last condition, the activation of the Complement System also amplifies the cytokine storm and the pathogenicity of coronavirus infection. Experimental treatment with Complement inhibitors has been an enthusiastic field of intense investigation in search of a promising additional therapy in severe COVID-19 patients.