Modulation of gut microbiota with probiotics as a strategy to counteract endogenous and exogenous neurotoxicity.

The existing data demonstrate that probiotic supplementation affords protective effects against neurotoxicity of exogenous (e.g., metals, ethanol, propionic acid, aflatoxin B1, organic pollutants) and endogenous (e.g., LPS, glucose, Aß, phospho-tau, α-synuclein) agents. Although the protective mechanisms of probiotic treatments differ between various neurotoxic agents, several key mechanisms at both the intestinal and brain levels seem inherent to all of them. Specifically, probiotic-induced improvement in gut microbiota diversity and taxonomic characteristics results in modulation of gut-derived metabolite production with increased secretion of SFCA. Moreover, modulation of gut microbiota results in inhibition of intestinal absorption of neurotoxic agents and their deposition in brain. Probiotics also maintain gut wall integrity and inhibit intestinal inflammation, thus reducing systemic levels of LPS. Centrally, probiotics ameliorate neurotoxin-induced neuroinflammation by decreasing LPS-induced TLR4/MyD88/NF-κB signaling and prevention of microglia activation. Neuroprotective mechanisms of probiotics also include inhibition of apoptosis and oxidative stress, at least partially by up-regulation of SIRT1 signaling. Moreover, probiotics reduce inhibitory effect of neurotoxic agents on BDNF expression, on neurogenesis, and on synaptic function. They can also reverse altered neurotransmitter metabolism and exert an antiamyloidogenic effect. The latter may be due to up-regulation of ADAM10 activity and down-regulation of presenilin 1 expression. Therefore, in view of the multiple mechanisms invoked for the neuroprotective effect of probiotics, as well as their high tolerance and safety, the use of probiotics should be considered as a therapeutic strategy for ameliorating adverse brain effects of various endogenous and exogenous agents.

Role of gut microbiota in the modulation of the health effects of advanced glycation end­products (Review).

The aim of the present review was to summarize the potential interactive effects between the gut microbiota and advanced glycation end­product (AGE) accumulation and toxicity in the host, and to reveal potential the mediatory effects of the gut microbiota on AGE­related health effects. The existing data demonstrate that dietary AGEs can have a significant impact on the richness and diversity of the gut microbiota, although the particular effect is dependent on the type of species, as well as the exposure dose. In addition, the gut microbiota may metabolize dietary AGEs. It has been also demonstrated that the characteristics of the gut microbiota, including its richness and relative abundance of certain taxa, is tightly associated with AGE accumulation in the host organism. In turn, a bilateral interplay between AGE toxicity and the modulation of the gut microbiota may contribute to pathogenesis of ageing and diabetes­associated diseases. Bacterial endotoxin lipopolysaccharide appears as the molecule that mediates the interactions between the gut microbiota and AGE toxicity, specifically via the modulation of the receptor for AGE signaling. Therefore, it is proposed that the modulation of the gut microbiota using probiotics or other dietary interventions may have a significant impact on AGE­induced glycative stress and systemic inflammation.

Gut Microbiota as a Mediator of Essential and Toxic Effects of Zinc in the Intestines and Other Tissues.

The objective of the present study was to review the existing data on the association between Zn status and characteristics of gut microbiota in various organisms and the potential role of Zn-induced microbiota in modulating systemic effects. The existing data demonstrate a tight relationship between Zn metabolism and gut microbiota as demonstrated in Zn deficiency, supplementation, and toxicity studies. Generally, Zn was found to be a significant factor for gut bacteria biodiversity. The effects of physiological and nutritional Zn doses also result in improved gut wall integrity, thus contributing to reduced translocation of bacteria and gut microbiome metabolites into the systemic circulation. In contrast, Zn overexposure induced substantial alterations in gut microbiota. In parallel with intestinal effects, systemic effects of Zn-induced gut microbiota modulation may include systemic inflammation and acute pancreatitis, autism spectrum disorder and attention deficit hyperactivity disorder, as well as fetal alcohol syndrome and obesity. In view of both Zn and gut microbiota, as well as their interaction in the regulation of the physiological functions of the host organism, addressing these targets through the use of Zn-enriched probiotics may be considered an effective strategy for health management.

Zinc and respiratory tract infections: Perspectives for COVID­19 (Review).

In view of the emerging COVID­19 pandemic caused by SARS­CoV­2 virus, the search for potential protective and therapeutic antiviral strategies is of particular and urgent interest. Zinc is known to modulate antiviral and antibacterial immunity and regulate inflammatory response. Despite the lack of clinical data, certain indications suggest that modulation of zinc status may be beneficial in COVID­19. In vitro experiments demonstrate that Zn2+ possesses antiviral activity through inhibition of SARS­CoV RNA polymerase. This effect may underlie therapeutic efficiency of chloroquine known to act as zinc ionophore. Indirect evidence also indicates that Zn2+ may decrease the activity of angiotensin­converting enzyme 2 (ACE2), known to be the receptor for SARS­CoV­2. Improved antiviral immunity by zinc may also occur through up­regulation of interferon α production and increasing its antiviral activity. Zinc possesses anti­inflammatory activity by inhibiting NF­κB signaling and modulation of regulatory T­cell functions that may limit the cytokine storm in COVID­19. Improved Zn status may also reduce the risk of bacterial co­infection by improving mucociliary clearance and barrier function of the respiratory epithelium, as well as direct antibacterial effects against S. pneumoniae. Zinc status is also tightly associated with risk factors for severe COVID­19 including ageing, immune deficiency, obesity, diabetes, and atherosclerosis, since these are known risk groups for zinc deficiency. Therefore, Zn may possess protective effect as preventive and adjuvant therapy of COVID­19 through reducing inflammation, improvement of mucociliary clearance, prevention of ventilator­induced lung injury, modulation of antiviral and antibacterial immunity. However, further clinical and experimental studies are required.

Gut as a target for cadmium toxicity.

The primary objective of the present study was to review the impact of Cd exposure on gut microbiota and intestinal physiology, as well as to estimate whether gut may be considered as the target for Cd toxicity. The review is based on literature search in available databases. The existing data demonstrate that the impact of Cd on gut physiology is two-sided. First, Cd exposure induces a significant alteration of bacterial populations and their relative abundance in gut (increased Bacteroidetes-to-Firmicutes ratio), accompanied by increased lipopolysaccharide (LPS) production, reflecting changed metabolic activity of the intestinal microbiome. Second, in intestinal wall Cd exposure induces inflammatory response and cell damage including disruption of tight junctions, ultimately leading to increased gut permeability. Together with increased LPS production, impaired barrier function causes endotoxinemia and systemic inflammation. Hypothetically, Cd-induced increase gut permeability may also result in increased bacterial translocation. On the one hand, bacteriolysis may be associated with aggravation of endotoxemia. At the same time, together with Cd-induced impairment of macrophage inflammatory response, increased bacterial translocation may result in increased susceptibility to infections. Such a supposition is generally in agreement with the finding of higher susceptibility of Cd-exposed mice to infections. The changed microbiome metabolic activity and LPS-induced systemic inflammation may have a significant impact on target organs. The efficiency of probiotics in at least partial prevention of the local (intestinal) and systemic toxic effects of cadmium confirms the role of altered gut physiology in Cd toxicity. Therefore, probiotic treatment may be considered as the one of the strategies for prevention of Cd toxicity in parallel with chelation, antioxidant, and anti-inflammatory therapy.

Effective Treatment of Staphylococcal Scalded Skin Syndrome with Platelet Microbicidal Protein in CBRB-Rb(8.17)1Iem Mice Model.

Skin and soft-tissue infections are among the most common infections. Staphylococcus aureus may cause a number of toxin-mediated diseases, including staphylococcal scalded skin syndrome (SSSS). The therapeutic efficacy of some antimicrobial peptides was recently evaluated in a mouse model of SSSS. This study is the first in vivo demonstration of the use of PMP to improve outcome of SSSS. Twenty-four CBRB-Rb(8.17)1Iem female mice naturally infected by endogenous S. aureus with SSSS symptoms were used in this work and divided into two equal groups. From neck of each mouse was isolated and identified endogenous exfoliative producing strain of S. aureus. PMP was obtained from human platelets and tested against Bacillus subtilis ATCC 6633. PMP had bactericidal activity against B. subtilis ATTC 6633 and endogenous strain of S. aureus at 2.0 ± 0.5 and 14.5 ± 0.5 µg/ml, respectively. At 4 weeks, the mice of experimental group were treated subcutaneous near exfoliative zone with 0.2 ml of PMP in final concentration 10 µg/ml every day. Control mice was injected with 0.2 ml 0.9% NaCl. At 1 day of experiment maximal zone of alopecia was at PMP-treating group (380 ± 20 mm(2)) in comparison with control group (167 ± 10 mm(2), p < 0.01). At 50 day of observation (22nd day after the end of treatment), the square of alopecia in control group was 1220 ± 40 mm(2) in comparison with 870 ± 17 mm(2) in experimental group (p < 0.01). The antistaphylococcal in vivo activity of PMP demonstrated in present study makes these molecules potentially useful for treatment of SSSS.

The Effect of Brief Exposure to Sub-Therapeutic Concentrations of Chlorhexidine Digluconate on the Susceptibility of Staphylococci to Platelet Microbicidal Protein.

BACKGROUND: Antiseptic agents are widely used in hospitals and are essential when prevention and control of nosocomial infections is required. It is necessary to consider several aspects that affect the biocide activity because they have direct impact on the nosocomial infection rate. Organisms belonging to the Staphylococcus genus are involved in such infections and chlorhexidine digluconate (CHXD) is one of the most used antiseptic agents for human and animal health. In the context of such infections, anti-bacterial peptides have been isolated from platelets and have been termed platelet microbicidal proteins (PMP). Platelet microbicidal proteins have been shown to enhance the bacterial inhibitory activities of sub-therapeutic concentrations of antibiotics. The main objective of this study was to investigate the effect of brief exposure to different sub-therapeutic concentrations of CHXD on the susceptibility of staphylococci to PMP. METHODS: The influence of brief exposure to three different sub-therapeutic concentrations of CHXD (0.005%, 0.0025%, and 0.00125%) on the subsequent staphylocidal effect of PMP was evaluated. RESULTS: Among all clinical staphylococcal strains studied, all isolates were considered to be resistant to the bactericidal action of PMP. Exposure of staphylococci to CHXD prior to PMP resulted in significantly increased staphylococcal killing compared with the killing achieved with PMP alone. This enhanced effect was most marked for concentrations of CHXD of 0.005%. CONCLUSION: The combined data indicate that PMP exerts cooperative bactericidal effect with CHXD. The anti-staphylococcal PMP and CHXD synergistic activity in vitro demonstrated in the present study make these molecules potentially useful for preventing endovascular catheter-associated infections. Future research based on animal and human models is needed to elucidate the in vivo efficacies and toxicities and utility in clinical practice.

Evaluation of antitumor activity of platelet microbicidal protein on the model of transplanted breast cancer in CBRB-Rb(8.17)1Iem mice.

Breast cancer is the most common women's cancer in the world. There is considerable current interest in developing anticancer agents with a new mode of action because of the development of resistance by cancer cells towards current anticancer drugs. Mamalian cells have been shown to contain small, cationic, microbicidal peptides. Antimicrobial peptides have drawn attention as a promising alternative to current antitumor agents. Such peptides have been isolated both from animal and human platelets and have been termed platelets microbicidal proteins (PMP). The aim of this work was to study antitumor activity of PMP in vivo on the model of mouse breast cancer in comparison with antitumor hexapeptide Arg-alpha-Asp-Lys-Val-Tyr-Arg (Immunofan). We demonstrated that the tumors treated with PMP were significant smaller than the control groups (P < 0.05). In experiments in vivo using CBRB-Rb(8.17)1Iem mice with transplanted tumors PMP inhibited tumor growth during the treatments and after its discontinuation. These findings indicate that PMP can exert antitumor effects. Therefore, PMP may be used for the development of therapy for the intervention of breast cancer.

Influence of Plantaginaceae species on E. coli K12 growth in vitro: Possible relation to phytochemical properties.

CONTEXT: The data concerning the influence of Plantaginaceae water extracts on bacterial growth are contradictory. OBJECTIVE: This study investigates the influence of Plantago maxima Juss. ex Jacq., Plantago lanceolata L., Plantago major L., Veronica teucrium L., Veronica spicata L., and Veronica incana L. aqueous extracts on growth of Escherichia coli K12 culture and the relation to antioxidant, reducing, and iron-binding activities. MATERIALS AND METHODS: Aqueous extracts were prepared from the dried leaves with the final concentration of 1/10, 1/15, 1/20, 1/25, 1/30, 1/35, and 1/40 (w/w). Comparative analysis of total flavonoids, iridoids, and tannins in Plantaginaceae species was performed. Iron-binding, antioxidant, and reducing activities of plant extracts were analyzed spectrophotometrically. The influence of plant extracts on E. coli K12 growth was studied in vitro by estimating the bacterial growth in the extract-containing medium. RESULTS: Total tannin content in plant leaves positively correlated with iron-binding activity (r = 0.641), whereas total flavonoids correlated with antioxidant activity (r = 0.687). In an in vitro model, it is estimated that water extracts of studied Plantaginaceae species stimulated bacterial growth. Prebiotic activity significantly of 1/20 and 1/40 plant extracts positively correlated with antioxidant (r = 0.589; r = 0.576, respectively) and reducing activity (r = 0.721; r = 0.620, respectively) of plant aqueous extracts at 6-24 h. Negative correlation was observed between iron-binding activity and bacterial growth (r = -0.503 and r = -0.534 for 1/20 and 1/40 extracts, respectively). CONCLUSION: Aqueous Plantaginaceae extracts possess prebiotic activity depending on the phytochemical content of plant leaves.

Plantago maxima leaves extract inhibits adipogenic action of a high-fat diet in female Wistar rats.

PURPOSE: The primary objective of this study is to investigate the content of biologically active compounds producing an antioxidant effect in Plantago maxima and their influence on main mechanisms of dietary obesity development. METHODS: Biologically active compounds in P. maxima were tested using paper chromatography. In in vivo experiment, high-fat-fed Wistar rats obtained P. maxima water extract for 3 months. Morphometric parameters, weight gain, serum adipokines, and cytokines, as well as oxidative stress biomarkers in rats' tissues were evaluated. Gut microflora was also examined. RESULTS: Plantago maxima leaves used in the experiment contained significant amount of flavonoids, iridoids, phenol carboxylic acids, and tannins and ascorbic acid. Our in vivo experiment data demonstrate that P. maxima water extract prevents excessive adiposity in a diet-induced model. P. maxima consumption reduced serum leptin (twofold), macrophage chemoattractant protein-1 (sevenfold), tumornecrosis factor-α (25%), and interleukine-6 (26%) levels. P. maxima water extract decreased adipose tissue oxidative stress biomarkers in rats fed a high-fat diet. In addition, increased bacterial growth in the diet-induced obesity model was reversed by the P. maxima extract treatment. CONCLUSION: Plantago maxima water extract possessed antiadipogenic, antidiabetic, antiinflammatory, antioxidant activity, and normalized gut microflora in a rat model of diet-induced excessive adiposity due to a high content of biologically active compounds.

Phenotypic differences between coagulase-negative staphylococci isolated from seminal fluid of healthy men and men suffering from chronic prostatitis syndrome.

Chronic prostatitis syndrome (CPS) is a common urologic condition that many clinicians find difficult to diagnose and treat effectively. The most common causative agents of CPS among Gram-positive bacteria are coagulase-negative staphylococci (CNS). We compared phenotypic properties among CNS isolated from semen of healthy men and patients with CPS. A significantly higher proportion of CPS strains demonstrated inhibition of lysozyme and platelet microbicidal protein. Identifying these phenotypic characteristics in clinical laboratories would be helpful to differentiate which staphylococcal bacteriospermia case should be treated and which should not.

Phenotypic differences between coryneform bacteria isolated from seminal fluid of healthy men and men with chronic prostatitis syndrome.

We compared the potential phenotypic properties of coryneform bacteria associated with chronic prostatitis syndrome (CPS), such as secretory inhibitor of lysozyme (SIL) and secretory inhibitor of platelet microbicidal protein (SIPMP). A total of 110 clinical isolates of coryneform bacteria isolated from the seminal fluid of healthy men and men with CPS were tested. SIPMP production was tested by inhibiting platelet microbicidal protein (PMP) bioactivity against Bacillus subtilis, and was expressed as percentage of inhibition of PMP bactericidal activity. SIL production was tested by inhibiting lysozyme activity against Micrococcus lysodeikticus and was expressed in microgram per millilitre of inactivated lysozyme. A significantly higher proportion of CPS strains (58.7% vs. 19.2 %) was SIPMP-positive compared with non-CPS strains (P < 0.01). Of the CPS strains tested, 77.8% were SIL-positive compared with 34% of the non-CPS isolates (P < 0.05). These results suggest that the diagnosis of CPS should not rely solely on classical parameters, for example, the identification and counting of microorganisms, but the functional significance of these parameters must be estimated, possibly by the concentration of different bacterial substrains, detection of opportunistic microorganisms with pathogenic properties, such as pronounced resistance to the cationic antimicrobial peptides, and/or the ability to inhibit the antimicrobial host defence factors.

Assessment of a microplate method for detection of staphylococcal secretory inhibitor of platelet microbicidal protein.

We developed a novel microplate spectrophotometric assay for the detection of staphylococcal secretory inhibitor of platelet microbicidal protein (SIPMP) in

Microflora of the seminal fluid of healthy men and men suffering from chronic prostatitis syndrome.

Chronic prostatitis syndrome (CPS) is a common urologic condition that many clinicians find difficult to diagnose and treat effectively. The information about the composition of the flora of the seminal fluid in healthy men and patients with CPS is limited. The aim of this study was to define the microbial communities present in the seminal fluid of healthy men and patients with CPS and at in vitro detection of decomplementary activity (DCA) phenotypes of isolates along with their comparison with isolates from patients with or without CPS. The bacteriological study was carried out to 48 healthy men and 60 men with CPS. Culture specimens were spread on various selective media. Bacterial DCA was tested by measuring the decrease in complement activity (CH(50)) under the influence of culture supernatants. The most common isolates in both groups were coryneforms, lactobacilli, coagulase-negative staphylococci, micrococci and streptococci. Enterobacteriaceae, enterococci and Staphylococcus aureus were isolated only from the CPS group. The organisms from seminal fluid of healthy men exerted DCA at 3.56 +/- 2.15; 2.47 +/- 1.23 and 4.36 +/- 2.2 anti-CH(50) for staphylococci, micrococci and diphtheroids respectively. The DCA of staphylococci, coryneforms, Enterobacteriaceae, enterococci and micrococci from CPS group were 12.8 +/- 2.1 (p < 0.05), 4.4 +/- 3.6 (p > 0.05), 16.8 +/- 2.1, 7.2 +/- 1.9 and 11.6 +/- 3.3 (p < 0.05) anti-CH(50) respectively. The data obtained in this study testify the microecological disorders in microbiota of seminal fluid in CPS.

Comparative Activities of Cattle and Swine Platelet Microbicidal Proteins.

The bactericidal activities of cattle and swine platelet microbicidal proteins (PMPs) with their comparison with human PMP were studied. Activities of PMP were tested against Bacillus subtilis, Bacillus cereus, Staphylococcus aureus, Staphylococcus epidermidis, Micrococcus lysodeikticus and Escherichia coli. B. subtilis and B. cereus were high susceptible to PMP at very low concentrations. Of the gram-positive cocci studied, M. lysodeikticus and S. aureus were the most, and S. epidermidis the least, susceptible. E. coli was found to be relatively resistant to the lethal action of all PMP. The findings of this study confirm that the existence of antimicrobial peptides is conserved among mammalian platelets.

Distribution of secretory inhibitor of platelet microbicidal protein among anaerobic bacteria isolated from stool of children with diarrhea.

AIM: To study the secretory inhibitor of platelet microbicidal protein (SIPMP) phenotypes of faecal anaerobic isolates from patients with diarrhea. METHODS: Faecal isolates of anaerobic bacteria (B. fragilis, n = 42; B. longum, n = 70; A. israelii, n = 21; E. lentum, n = 12) from children with diarrhea were tested. SIPMP production was tested by inhibition of platelet microbicidal protein (PMP) bioactivity against B. subtilis and was expressed as percentage of inhibition of PMP bactericidal activity. RESULTS: Among anaerobic isolates 80% of B. longum strains, 85.7% of A. israelii strains, 50% of E. lentum strains and 92.86% of B. fragilis strains were SIPMP-positive. The isolated anaerobic organisms demonstrated SIPMP production at a mean level of 13.8% +/- 0.7%, 14.7% +/- 1.8%, 3.9% +/- 0.9% (P < 0.05) and 26.8% +/- 7.5% (P < 0.05) for bifidobacteria, A. israelii, E. lentum and B. fragilis, respectively. CONCLUSION: Data from the present study may have significant implications in understanding the pathogenesis of microecological disorders in the intestine, as well as for future improvement in the prevention and therapy of anaerobe-associated infections.

Distribution of secretory inhibitor of platelet microbicidal protein among urethral isolates with its correlation with prostatitis.

AIM: To report the detection in vitro of secretory inhibitor of platelet microbicidal protein (SIPMP) phenotypes of urethral isolates along with a comparison with isolates from patients with or without chronic bacterial prostatitis (CBP). METHODS: Urethral isolates of Staphylococcus spp. (n=4), diphtheroids (n=28), micrococci (n=15), streptococci (n=21), Enterobacteriaceae (n=9) and Enterococcus faecalis (n=19) from patients with or without CBP were tested. SIPMP production was tested by inhibition of platelet microbicidal protein (PMP) bioactivity against Bacillus subtilis and was expressed as percentage of inhibition of PMP bactericidal activity. RESULTS: A significantly higher proportion of CBP-strains (57.78% vs. 16.67%) reduced PMP-induced killing of Bacillus subtilis than non-CBP strains did (P<0.01). SIPMP levels of staphylococci and Enterococcus faecalis from the CBP group were significantly higher than those of the control group. CONCLUSION: These results suggest that SIPMP production is associated with the CBP source. Data from the present study might have significant implications for the understanding of the pathogenesis of CBP.

Staphylococcal secretory inhibitor of platelet microbicidal protein is associated with prostatitis source.

This study reports the detection of an extracellular staphylococcal product, designated secretory inhibitor of platelet microbicidal protein (SIPMP), that causes local inhibition of the bactericidal action of platelet microbicidal protein (PMP) in the fluid phase. Urethral isolates of Staphylococcus aureus (n=24) and coagulase-negative staphylococci (CNS) (n=47) from patients with or without chronic bacterial prostatitis (CBP) were tested. SIPMP production was tested by inhibition of PMP bioactivity against Bacillus subtilis and was expressed as percentage inhibition of PMP bactericidal activity. The PMP susceptibility of staphylococcal strains was determined by exposing bacterial cells to serial dilutions of PMP. Staphylococci from patients without CBP produced SIPMP at levels of 10.3+/-1.2 and 13.25+/-1.72 % for S. aureus and CNS, respectively. Strains isolated from men with CBP inhibited PMP-induced killing of B. subtilis by 23.38+/-4.2 % (P<0.05) and 23.69+/-1.87 % (P<0.01) for S. aureus and CNS, respectively. SIPMP production correlated with staphylococcal resistance to PMP (r2=0.6082 and 0.7264 for S. aureus and CNS, respectively). SIPMP represents a hitherto unrecognized determinant of staphylococcal pathogenicity. These results suggest that SIPMP production is associated with the CBP source. Data from this study may have significant implications for the understanding of the pathogenesis of CBP.