Protective effect of the probiotic Lactobacillus acidophilus ATCC 4356 in BALB/c mice infected with Toxocara canis

Immunomodulation in the intestinal mucosa of mice supplemented with Lactobacillus rhamnosus (ATCC 7469) and infected with Toxocara canis

Toxocariasis is an anthropozoonosis caused by the helminth Toxocara canis that shows different clinical manifestations as visceral, ocular, or neurological toxocariasis forms. Probiotics have been studied as alternatives to prevent and treat this parasitosis. Lactobacillus rhamnosus is a prospect that presents immunomodulatory activity that acts to strengthen the intestinal barrier. In this context, the main objective of this study was to evaluate the protective capacity and immunomodulatory action of the probiotic Lactobacillus rhamnosus at the level of the intestinal mucosa in different stages of T. canis infection (acute and chronic). Mice were supplemented by oral gavage with 1 × 10⁷ UFC/mL L. rhamnosus for 15 days before inoculation with 100 embryonated eggs of T. canis. Euthanasia of mice was conducted at three different time points: 2, 15 and 30 days post-inoculation (PI). The brain, lungs and liver were collected to evaluate the intensity of infection. The small intestines were removed, and mucosal cells of the duodenum were collected to perform gene analysis of IFN-γ, IL-10, IL-4 and IL-13 by real-time polymerase chain reaction (qPCR). Jejunum and ileum segments were analysed by histological techniques. A reduction of 51% in infection intensity was observed in the tissue of supplemented animals evaluated 2 days PI; however, analysis of groups 15 and 30 days PI did not show a protective effect. The intestinal mucosa of supplemented animals presented an inflammatory process that initiated at 2 days PI, persisted at 15 days PI and had regressed at 30 days PI. IL-13 transcription was increased in the probiotic group 2 days after supplementation ended; however, the same increase was not observed in the group that was supplemented and infected. Toxocara canis modulated the local immune system, with suppression of IFN-γ at 2 days PI and increased levels of IL-4 and IL-10 at 15 days PI. These results indicate that, under the studied conditions, the protective effect of Lactobacillus rhamnosus against infection caused by T. canis is not related to IL-4, IL-10 or IFN-γ but could be influenced by IL-13 action at 2 days PI. The probiotic stimulated immune cell recruitment to the intestinal mucosa, which can be involved in the diminished capacity of larval penetration in the mucosa, resulting in the reduced infection intensity observed during acute infection.

Insights into the Mechanisms of Lactobacillus acidophilus Activity against Entamoeba histolytica by Using Thiol Redox Proteomics

Amebiasis is an intestinal disease transmitted by the protist parasite, Entamoeba histolytica. Lactobacillus acidophilus is a common inhabitant of healthy human gut and a probiotic that has antimicrobial properties against a number of pathogenic bacteria, fungi, and parasites. The aim of this study was to investigate the amebicide activity of L. acidophilus and its mechanisms. For this purpose, E. histolytica and L. acidophilus were co-incubated and the parasite's viability was determined by eosin dye exclusion. The level of ozidized proteins (OXs) in the parasite was determined by resin-assisted capture RAC (OX-RAC). Incubation with L. acidophilus for two hours reduced the viability of E. histolytica trophozoites by 50%. As a result of the interaction with catalase, an enzyme that degrades hydrogen peroxide (H2O2) to water and oxygen, this amebicide activity is lost, indicating that it is mediated by H2O2 produced by L. acidophilus. Redox proteomics shows that L. acidophilus triggers the oxidation of many essential amebic enzymes such as pyruvate: ferredoxin oxidoreductase, the lectin Gal/GalNAc, and cysteine proteases (CPs). Further, trophozoites of E. histolytica incubated with L. acidophilus show reduced binding to mammalian cells. These results support L. acidophilus as a prophylactic candidate against amebiasis.

Gut Microbiota Modulation as a Potential Target for the Treatment of Lung Infections

The gastrointestinal and respiratory systems are colonized by a complex ecosystem of microorganisms called the microbiota. These microorganisms co-evolved over millions of years with the host, creating a symbiotic relationship that is fundamental for promoting host homeostasis by producing bioactive metabolites and antimicrobial molecules, and regulating the immune and inflammatory responses. Imbalance in the abundance, diversity, and function of the gut microbiota (known as dysbiosis) have been shown to increase host susceptibility to infections in the lungs, suggesting crosstalk between these organs. This crosstalk is now referred to as the gut-lung axis. Hence, the use of probiotics, prebiotics, and synbiotics for modulation of gut microbiota has been studied based on their effectiveness in reducing the duration and severity of respiratory tract infections, mainly owing to their effects on preventing pathogen colonization and modulating the immune system. This review discusses the role and responses of probiotics, prebiotics, and synbiotics in the gut-lung axis in the face of lung infections.

Searching for the one(s): Using Probiotics as Anthelmintic Treatments

Helminths are a major health concern as over one billion people are infected worldwide and, despite the multiple efforts made, there is still no effective human vaccine against them. The most important drugs used nowadays to control helminth infections belong to the benzimidazoles, imidazothiazoles (levamisole) and macrocyclic lactones (avermectins and milbemycins) families. However, in the last 20 years, many publications have revealed increasing anthelmintic resistance in livestock which is both an economical and a potential health problem, even though very few have reported similar findings in human populations. To deal with this worrying limitation of anthelmintic drugs, alternative treatments based on plant extracts or probiotics have been developed. Probiotics are defined by the Food and Agriculture Organization as live microorganisms, which, when consumed in adequate amounts, confer a health benefit to the host. It has been proven that probiotic microbes have the ability to exert an immunomodulatory effect both at the mucosa and the systemic level. The immune response against gastrointestinal helminths is characterized as a type 2 response, with high IgE levels, increased numbers and/or activity of Th2 cells, type 2 innate lymphoid cells, eosinophils, basophils, mast cells, and alternatively activated macrophages. The oral administration of probiotics may contribute to controlling gastrointestinal helminth infections since it has been demonstrated that these microorganisms stimulate dendritic cells to elicit a type 2 or regulatory immune response, among other effects on the host immune system. Here we review the current knowledge about the use of probiotic bacteria as anthelmintic therapy or as a complement to traditional anthelmintic treatments. Considering all research papers reviewed, we may conclude that the effect generated by probiotics on helminth infection depends not only on the parasite species, their stage and localization but also on the administration scheme.

Multi-Probiotic Lactobacillus Supplementation Improves Liver Function and Reduces Cholesterol Levels in Jeju Native Pigs

Simple Summary

Probiotics are used in the food industry as feed additives to maintain the balance of animal gut microbiota. They are also considered to have potential therapeutic effects against liver diseases. This study showed that dietary Lactobacillus supplementation improved liver function and reduced cholesterol levels in Jeju native pigs, with Toll-like receptors (TLR) signaling as the primary response in the gut against Lactobacillus and TNF-α/IFN-γ as the central mediator cytokines in the gut and liver tissues. Lactobacillus supplementation may be applied to treat metabolic disorders of the liver, especially cholesterol-related disorders, in farm animals.

Abstract

We evaluated the dietary effects of multiple probiotics in Jeju native pigs, using basal diet and multi-probiotic Lactobacillus (basal diet with 1% multi-probiotics) treatments (n = 9 each) for 3 months. We analyzed growth performance, feed efficiency, backfat thickness, blood parameters, hematological profiles, adipokines, and immune-related cytokines in pig tissues. Average daily gain, feed intake, feed efficiency, backfat thickness, and body weight were not significantly different between both groups. In Lactobacillus group, total protein (p < 0.08) and bilirubin (p < 0.03) concentrations increased; blood urea nitrogen (p < 0.08), alkaline phosphatase (p < 0.08), and gamma-glutamyltransferase (p < 0.08) activities decreased. Lactobacillus group showed decreased adiponectin (p < 0.05), chemerin (p < 0.05), and visfatin expression in adipose tissues, and increased TLR4 (p < 0.05), MYD88 (p < 0.05), TNF-α (p < 0.001), and IFN-γ (p < 0.001) expression in the liver. Additionally, NOD1 (p < 0.05), NOD2 (p < 0.01), and MYD88 (p < 0.05) mRNA levels in proximal colon tissue upregulated significantly. Colon, longissimus dorsi muscle, fat tissue, and liver histological analyses revealed no significant differences between the groups. Conclusively, Lactobacillus supplementation improved liver function and reduced cholesterol levels. Its application may treat metabolic liver disorders, especially cholesterol-related disorders.