In addition to physical barriers, neutrophils are considered a part of the first line of immune defense. They can be found in the bloodstream, with a lifespan of 6-8 hours, and in tissue, where they can last up to seven days. The mechanisms that neutrophils utilize for host defense are phagocytosis, degranulation, cytokine production and, the most recently described, neutrophil extracellular trap (NET) production. NETs are DNA structures released due to chromatin decondensation and spreading, and they thus occupy 3-5 times the volume of condensed chromatin. Several proteins adhere to NETs, including histones and over 30 components of primary and secondary granules, among them components with bactericidal activity such as elastase, myeloperoxidase, cathepsin G, lactoferrin, pentraxin 3, gelatinase, proteinase 3, LL-37, peptidoglycan-binding proteins and others with bactericidal activity able to destroy virulence factors. Three models for NETosis are known to date. a) Suicidal NETosis, with a duration of 2-4 hours, is the best described model. b) In vital NETosis with nuclear DNA release, neutrophils release NETs without exhibiting loss of nuclear or plasma membrane within 5-60 minutes, and it is independent of ROS and the Raf/MERK/ERK pathway. c). The final type is Vital NETosis with release of mitochondrial DNA that is dependent on ROS and produced after stimuli with GM-CSF and LPS. Recent research has revealed neutrophils as more sophisticated immune cells that are able to precisely regulate their granular enzymes release by ion fluxes and can release immunomodulatory cytokines and chemokines that interact with various components of the immune system. Therefore, they can play a key role in autoimmunity and in autoinflammatory and metabolic diseases. In this review, we intend to show the two roles played by neutrophils: as a first line of defense against microorganisms and as a contributor to the pathogenesis of various illnesses, such as autoimmune, autoinflammatory and metabolic diseases.

Viruses are obligate intracellular pathogens that require the protein synthesis machinery of the host cells to replicate. These microorganisms have evolved mechanisms to avoid detection from the host immune innate and adaptive response, which are known as viral evasion mechanisms. Viruses enter the host through skin and mucosal surfaces that happen to be colonized by communities of thousands of microorganisms collectively known as the commensal microbiota, where bacteria have a role in the modulation of the immune system and maintaining homeostasis. These bacteria are necessary for the development of the immune system and to prevent the adhesion and colonization of bacterial pathogens and parasites. However, the interactions between the commensal microbiota and viruses are not clear. The microbiota could confer protection against viral infection by priming the immune response to avoid infection, with some bacterial species being required to increase the antiviral response. On the other hand, it could also help to promote viral evasion of certain viruses by direct and indirect mechanisms, with the presence of the microbiota increasing infection and viruses using LPS and surface polysaccharides from bacteria to trigger immunosuppressive pathways. In this work, we reviewed the interaction between the microbiota and viruses to prevent their entry into host cells or to help them to evade the host antiviral immunity. This review is focused on the influence of the commensal microbiota in the viruses' success or failure of the host cells infection.

The gut microbiota (GM) comprises billions of microorganisms in the human gastrointestinal tract. This microbial community exerts numerous physiological functions. Prominent among these functions is the effect on host immunity through the uptake of nutrients that strengthen intestinal cells and cells involved in the immune response. The physiological functions of the GM are not limited to the gut, but bidirectional interactions between the gut microbiota and various extraintestinal organs have been identified. These interactions have been termed interorganic axes by several authors, among which the gut–brain, gut–skin, gut–lung, gut–heart, and gut–metabolism axes stand out. It has been shown that an organism is healthy or in homeostasis when the GM is in balance. However, altered GM or dysbiosis represents a critical factor in the pathogenesis of many local and systemic diseases. Therefore, probiotics intervene in this context, which, according to various published studies, allows balance to be maintained in the GM, leading to an individual’s good health.

Animal digestive systems host microorganism ecosystems, including integrated bacteria, viruses, fungi, and others, that produce a variety of compounds from different substrates with healthy properties. Among these substrates, α-galacto-oligosaccharides (GOS) are considered prebiotics that promote the grow of gut microbiota with a metabolic output of Short Chain Fatty Acids (SCFAs). In this regard, we evaluated Lupinus albus GOS (LA-GOS) as a natural prebiotic using different animal models. Therefore, the aim of this work was to evaluate the effect of LA-GOS on the gut microbiota, SCFA production, and intestinal health in healthy and induced dysbiosis conditions (an ulcerative colitis (UC) model). Twenty C57BL/6 mice were randomly allocated in four groups (n = 5/group): untreated and treated non-induced animals, and two groups induced with 2% dextran sulfate sodium to UC with and without LA-GOS administration (2.5 g/kg bw). We found that the UC treated group showed a higher goblet cell number, lower disease activity index, and reduced histopathological damage in comparison to the UC untreated group. In addition, the abundance of positive bacteria to butyryl-CoA transferase in gut microbiota was significantly increased by LA-GOS treatment, in healthy conditions. We measured the SCFA production with significant differences in the butyrate concentration between treated and untreated healthy groups. Finally, the pH level in cecum feces was reduced after LA-GOS treatment. Overall, we point out the in vivo health benefits of LA-GOS administration on the preservation of the intestinal ecosystem and the promotion of SCFA production.

Introduction: Liver cirrhosis (LC) constitutes one of the main 10 causes of death worldwide. LC has a characteristic asymptomatic compensated phase followed by a progressive decompensated phase, in which diverse complications are presented. LC patients are highly prone to bacterial infections. The neutrophils in these patients present defects in the production of oxygen radicals, which are essential for bacteria elimination as in the activation of neutrophil extracellular traps (NETs). The main objective of this work was to determine the NETs and neutrophil activation markers in LC patients. Methodology: Neutrophil purification was done with Ficoll Histopaque from a sample of the peripheral blood of patients with compensated and decompensated LC. Neutrophils were activated with Phorbol 12-myristate 13-acetate to evaluate the release of NETs by means of fluorescence microscopy and fluorometry, while expression of activation markers (CD69, CD80, perforin, and CAP-18) was evaluated by flow cytometry. Results: A significant decrease in the release capability of NETs was observed as the level of LC in the patient increased. When comparing serum levels in inflammatory cytokines among the different study groups, significant differences were observed. No significant differences were detected on neutrophil activation markers; nevertheless, there was a correlation between diminution of CD69 and CD80 expression in decompensated patients. Conclusions: We demonstrated that LC patients with neutrophil extracellular trap release deficiencies could have an increased rate of complications.