Lactobacillus HY2782 and Bifidobacterium HY8002 Decrease Airway Hyperresponsiveness Induced by Chronic PM2.5 Inhalation in Mice

Bifidobacteria in disease: from head to toe

Bifidobacteria as a strictly anaerobic gram-positive bacteria, is widely distributed in the intestine, vagina and oral cavity, and is one of the first gut flora to colonize the early stages of life. Intestinal flora is closely related to health, and dysbiosis of intestinal flora, especially Bifidobacteria, has been found in a variety of diseases. Numerous studies have shown that in addition to maintaining intestinal homeostasis, Bifidobacteria may be involved in diseases covering all parts of the body, including the nervous system, respiratory system, genitourinary system and so on. This review collects evidence for the variation of Bifidobacteria in typical diseases among various systems, provides mild and effective therapeutic options for those diseases that are difficult to cure, and moves Bifidobacteria from basic research to further clinical applications.

Possible modulating functions of probiotic Lactiplantibacillus plantarum in particulate matter-associated pulmonary inflammation

Pulmonary disease represents a substantial global health burden. Increased air pollution, especially fine particulate matter (PM2.5) is the most concerned proportion of air pollutants to respiratory health. PM2.5 may carry or combine with other toxic allergens and heavy metals, resulting in serious respiratory allergies and anaphylactic reactions in the host. Available treatment options such as antihistamines, steroids, and avoiding allergens/dust/pollutants could be limited due to certain side effects and immense exposure to air pollutants, especially in most polluted countries. In this mini-review, we summarized how PM2.5 triggers respiratory hyperresponsiveness and inflammation, and the probiotic Lactiplantibacillus plantarum supplementation could minimize the risk of the same. L. plantarum may confer beneficial effects in PM2.5-associated pulmonary inflammation due to significant antioxidant potential. We discussed L. plantarum's effect on PM2.5-induced reactive oxygen species (ROS), inflammatory cytokines, lipid peroxidation, and DNA damage. Available preclinical evidence shows L. plantarum induces gut-lung axis, SCFA, GABA, and other neurotransmitter signaling via gut microbiota modulation. SCFA signals are important in maintaining lung homeostasis and regulating intracellular defense mechanisms in alveolar cells. However, significant research is needed in this direction to contemplate L. plantarum's therapeutic potential in pulmonary allergies.

Liubao tea extract ameliorates ovalbumin-induced allergic asthma by regulating gut microbiota in mice

Asthma, a chronic airway inflammatory disease, has a complicated pathogenesis and limited therapeutic treatment. Evidence shows that the intestinal microbiota exhibits crucial functional interaction with asthma syndrome. Liubao tea (LBT), a type of postfermented tea in China, positively modulates gut microbiota. However, the potential benefits of LBT extract (LBTE) for allergic asthma are still not understood. Herein, the anti-inflammatory effects of LBTE and its modulation of the gut microbiota of asthmatic mice induced by ovalbumin were explored. The results demonstrate that LBTE significantly inhibited airway hyper-responsiveness and restrained the proliferation of proinflammatory cytokines and inflammatory cells associated with allergic asthma. Additionally, LBTE suppressed inflammatory infiltration, mucus secretion, and excessive goblet cell production by downregulating the gene expression of inflammatory indicators. Interestingly, fecal microbiota transplantation results further implied that the modulation of LBTE on gut microbiota played an essential role in alleviating airway inflammatory symptoms of allergic asthma.

Systematic Investigation of the Effect of Lactobacillus acidophilus TW01 on Potential Prevention of Particulate Matter (PM)2.5-Induced Damage Using a Novel In Vitro Platform

Exposure to ambient particulate matter (PM) and cigarette smoking (CS) is a risk factor for respiratory/lung infections and metabolic disorders. Lung-gut axis disruption involving the upregulation of oxidative stress, systemic inflammation, and gut barrier dysfunction by PM is one of the potential mechanisms. Thus, we designed a novel in vitro platform for pre-selecting probiotics with potentially protective effects against PM-induced lung damage through the lung-gut axis to reduce animal usage. The results showed that a high dose of Lactobacillus acidophilus TW01 (1 × 108 CFU/mL) inhibited reactive oxygen species (ROS) production. This strain could also reduce respiratory epithelial cell death induced by cigarette smoke extraction (CSE), as well as promoting Caco-2 cell migration in 1 × 106 CFU/mL. Although further animal experiments are needed to validate the in vitro findings, L. acidophilus TW01 is a promising probiotic strain for the potential prevention of PM2.5-induced damage.

Lung-gut axis of microbiome alterations following co-exposure to ultrafine carbon black and ozone

BACKGROUND

Microbial dysbiosis is a potential mediator of air pollution-induced adverse outcomes. However, a systemic comparison of the lung and gut microbiome alterations and lung-gut axis following air pollution exposure is scant. In this study, we exposed male C57BL/6J mice to inhaled air, CB (10 mg/m3), O3 (2 ppm) or CB + O3 mixture for 3 h/day for either one day or four consecutive days and were euthanized 24 h post last exposure. The lung and gut microbiome were quantified by 16 s sequencing.

RESULTS

Multiple CB + O3 exposures induced an increase in the lung inflammatory cells (neutrophils, eosinophils and B lymphocytes), reduced absolute bacterial load in the lungs and increased load in the gut. CB + O3 exposure was more potent as it decreased lung microbiome alpha diversity just after a single exposure. CB + O3 co-exposure uniquely increased Clostridiaceae and Prevotellaceae in the lungs. Serum short chain fatty acids (SCFA) (acetate and propionate) were increased significantly only after CB + O3 co-exposure. A significant increase in SCFA producing bacterial families (Ruminococcaceae, Lachnospiraceae, and Eubacterium) were also observed in the gut after multiple exposures. Co-exposure induced significant alterations in the gut derived metabolite receptors/mediator (Gcg, Glp-1r, Cck) mRNA expression. Oxidative stress related mRNA expression in lungs, and oxidant levels in the BALF, serum and gut significantly increased after CB + O3 exposures.

CONCLUSION

Our study confirms distinct gut and lung microbiome alterations after CB + O3 inhalation co-exposure and indicate a potential homeostatic shift in the gut microbiome to counter deleterious impacts of environmental exposures on metabolic system.

Cell-Free Supernatant from Lactobacillus and Streptococcus Strains Modulate Mucus Production via Nf-κB/CREB Pathway in Diesel Particle Matter-Stimulated NCI-H292 Airway Epithelial Cells

Airway epithelial cells are a major site of airway inflammation and may play an important role in the pathogenesis of chronic obstructive pulmonary disease (COPD). Diesel particulate matter (DPM) is associated with mucus hypersecretion and airway inflammation and has been reported to overexpress airway mucin in the NCI-H292 airway epithelial cells. Therefore, regulation of mucin hypersecretion is essential for developing novel anti-inflammatory agents. This study aimed to investigate the effects of cell-free supernatant (CFS) from Lactobacillus and Streptococcus on nitro oxide (NO) production in RAW264.7 and proteins associated with mucus production in NCI-H292 cells. We observed that NO production was reduced by CFS from Lactobacillus and Streptococcus in RAW 264.7, and MUC4, MUC5AC, and MUC5B gene expression was increased by phosphorylation of nuclear factor kappa B (NF-κB) p65 and cAMP response element-binding protein (CREB) in DPM-stimulated NCI-H292 cells. However, CFS from L. paracasei MG4272, MG4577, L. gasseri MG4247, and S. thermophilus MG5140 inhibited mRNA expression related to mucus production by downregulating the CREB/NfκB signaling pathway. These results suggest that CFS from L. paracasei MG4272, MG4577, L. gasseri MG4247, and S. thermophilus MG5140 can contribute as a strategic candidate to the prevention of airway inflammatory diseases caused by DPM.

Particulate matter of air pollution may increase risk of kidney failure in IgA nephropathy

IgA nephropathy (IgAN) is characterized by deposition of galactose-deficient IgA1 (Gd-IgA1) in glomerular mesangium associated with mucosal immune disorders. Since environmental pollution has been associated with the progression of chronic kidney disease in the general population, we specifically investigated the influence of exposure to fine particulate matter less than 2.5 μm in diameter (PM2.5) on IgAN progression. Patients with biopsy-proven primary IgAN were recruited from seven Chinese kidney centers. PM2.5 exposure from 1998 to 2016 was derived from satellite aerosol optical depth data and a total of 1,979 patients with IgAN, including 994 males were enrolled. The PM2.5 exposure levels for patients from different provinces varied but, in general, the PM2.5 exposure levels among patients from the north were higher than those among patients from the south. The severity of PM2.5 exposure in different regions was correlated with regional kidney failure burden. In addition, each 10 μg/m³ increase in annual average concentration of PM2.5 exposure before study entry (Hazard Ratio, 1.14; 95% confidence interval, 1.06-1.22) or time-varying PM2.5 exposure after study entry (1.10; 1.01-1.18) were associated with increased kidney failure risk after adjustment for age, gender, estimated glomerular filtration rate, urine protein, uric acid, hemoglobin, mean arterial pressure, Oxford classification, glucocorticoid and renin-angiotensin system blocker therapy. The associations were robust when the time period, risk factors of cardiovascular diseases or city size were further adjusted on the basis of the above model. Thus, our results suggest that PM2.5 is an independent risk factor for kidney failure in patients with IgAN, but these findings will require validation in more diverse populations and other geographic regions.

Immunostimulatory effects of dairy probiotic strains Bifidobacterium animalis ssp. lactis HY8002 and Lactobacillus plantarum HY7717

Previous studies reported that Bifidobacterium animalis ssp. lactis HY8002 (HY8002) improved intestinal integrity and had immunomodulatory effects. Lactobacillus plantarum HY7717 (HY7717) was screened in vitro from among 21 other lactic acid bacteria (LAB) and demonstrated nitric oxide (NO) production. The aims of this study were to investigate the individual and combined ex vivo and in vivo effects of LAB strains HY8002 and HY7717 at immunostimulating mice that have been challenged with an immunosuppressant drug. The combination of HY8002 and HY7717 increased the secretion of cytokines such as interferon (IFN)-γ, interleukin (IL)-12, and tumor necrosis factor (TNF)-α in splenocytes. In a cyclophosphamide (CTX)-induced immunosuppression model, administration of the foregoing LAB combination improved the splenic and hematological indices, activated natural killer (NK) cells, and up-regulated plasma immunoglobulins and cytokines. Moreover, this combination treatment increased Toll-like receptor 2 (TLR2) expression. The ability of the combination treatment to upregulate IFN-γ and TNF-α in the splenocytes was inhibited by anti-TLR2 antibody. Hence, the immune responses stimulated by the combination of HY8002 and HY7717 are associated with TLR2 activation. The preceding findings suggest that the combination of the HY8002 and HY7717 LAB strains could prove to be a beneficial and efficacious immunostimulant probiotic supplement. The combination of the two probiotic strains will be applied on the dairy foods including yogurt and cheese.

Lactobacillus paragasseri BBM171 Ameliorates Allergic Airway Inflammation Induced by Ovalbumin in Mice via Modulating the Th1/Th2 Balance

Supplementation with specific probiotics has been shown to improve allergic airway symptoms. This study aimed to investigate immunomodulatory effects of a potential probiotic strain isolated from breast milk, Lactobacillus paragasseri BBM171 (BBM171), in an ovalbumin (OVA)-induced allergic mouse model. OVA-sensitized and OVA-challenged BALB/c mice were orally administered live or heat-inactivated BBM171 for 48 consecutive days. After the last allergen challenge, serum immunoglobulin (Ig) levels, inflammatory cell levels in the lungs, and cytokine levels in bronchoalveolar lavage fluid (BALF) were assessed. The results showed that oral administration of live or heat-inactivated BBM171 decreased serum levels of total IgE, OVA-specific IgE, and OVA-specific IgG1, while increasing OVA-specific IgG2a and reducing the extent of airway inflammation in OVA-induced allergic mice. In addition, both live and heat-inactivated BBM171 modulated the cytokine profile in BALF to a type 1 T helper (Th1) response. Furthermore, ex vivo experiments using OVA-induced allergic mouse splenocytes showed that both live and heat-inactivated BBM171 could regulate the Th1/Th2 balance, decrease the proinflammatory cytokine interleukin (IL)-17 level, and increase the anti-inflammatory cytokine IL-10 level. Taken together, these results suggest that oral administration of live or heat-inactivated BBM171 improved allergen-induced airway inflammation symptoms by modulating the host immune response toward Th1 dominance.

Lactobacillus casei HY2782 and Pueraria lobata Root Extract Complex Ameliorates Particulate Matter-Induced Airway Inflammation in Mice by Inhibiting Th2 and Th17 Immune Responses

This study aimed to investigate the effects of Lactobacillus casei HY2782 and Pueraria lobata root extract complex (HY2782 complex) in mitigating airway inflammation resulting from exposure to particulate matter ≤2.5 μm in diameter (PM2.5) in an animal model. Chronic inflammatory airway disease is associated with Th2-related cytokines interleukin (IL)-4, IL-5, and IL-13 and Th17-related cytokine IL-17A, which are the major contributors to allergy and asthma. Results indicated that PM2.5 elevates allergen-related airway inflammation and respiratory hyperresponsiveness in C57BL/6 mice. The HY2782 complex significantly reduced Th2/Th17-derived cytokines IL-4, IL5, IL-13, and IL-17A; immunoglobulin E; and leukotriene C₄ in bronchoalveolar lavage fluid (BALF) and serum. Furthermore, the HY2782 complex was associated with the modulation of oxidative stress-related genes. Administration of the HY2782 complex resulted in a markedly reduced number of neutrophils and eosinophil infiltration in BALF. Histopathological observation of lung tissue also showed reduced inflammatory cell infiltration into airways and surrounding tissue. The HY2782 complex may be a promising candidate for the preventive therapy of allergic diseases and airway inflammation caused by PM2.5 inhalation.

Supplementation with heat-inactivated Lacticaseibacillus paracasei K47 ameliorates allergic asthma in mice by regulating the Th1/Th2 balance

Asthma is a chronic inflammatory disease related to the immune response of type 2 T helper cells (Th2), which affects all age groups. The incidence of asthma is increasing worldwide, and it has become a significant public health problem. This study aimed to investigate the immunomodulatory effects of Lacticaseibacillus (formerly Lactobacillus) paracasei K47 on mice with ovalbumin (OVA)-induced allergy. The consequences of orally administered heat-inactivated K47 in OVA-sensitised/challenged BALB/c mice were evaluated by assessing the serum levels of immunoglobulins (Igs), airway hyperresponsiveness (AHR), and bronchoalveolar lavage fluid (BALF) cytokine. In addition, the effect of K47 on type 1 T helper cells (Th1)/Th2 cytokine production in splenocytes from OVA-sensitised mice was evaluated. The results revealed that supplementation with K47 remarkably reduced serum levels of total IgE, OVA-specific IgE, and OVA-specific IgG1 in OVA-sensitised/challenged mice. In addition, K47 intervention ameliorated AHR and suppressed the accumulation of inflammatory cells in the BALF of OVA-sensitised/challenged mice. Furthermore, the immunomodulatory ability of K47 was mediated by regulation of the cytokine profile toward the Th1 response in the BALF, and splenocytes of OVA-sensitised mice. Taken together, these results suggested that K47 can modulate the host immune response to ameliorate AHR and inflammation in allergic asthma.

Air Pollution and the Airways: Lessons from a Century of Human Urbanization

Since the industrial revolution, air pollution has become a major problem causing several health problems involving the airways as well as the cardiovascular, reproductive, or neurological system. According to the WHO, about 3.6 million deaths every year are related to inhalation of polluted air, specifically due to pulmonary diseases. Polluted air first encounters the airways, which are a major human defense mechanism to reduce the risk of this aggressor. Air pollution consists of a mixture of potentially harmful compounds such as particulate matter, ozone, carbon monoxide, volatile organic compounds, and heavy metals, each having its own effects on the human body. In the last decades, a lot of research investigating the underlying risks and effects of air pollution and/or its specific compounds on the airways, has been performed, involving both in vivo and in vitro experiments. The goal of this review is to give an overview of the recent data on the effects of air pollution on healthy and diseased airways or models of airway disease, such as asthma or chronic obstructive pulmonary disease. Therefore, we focused on studies involving pollution and airway symptoms and/or damage both in mice and humans.

PM2.5 induces intestinal damage by affecting gut microbiota and metabolites of rats fed a high-carbohydrate diet

PM_2.5 has a major impact on the gastrointestinal system, but the specific mechanism behind this action is not fully understood. Current studies have focused on the relationship between PM_2.5 and intestinal flora disorder, while ignoring the important influence of diet on gut microbes. In this study, SD rats were fed either a normal, high-fat, or high-carbohydrate diet for two months and exposed to PM_2.5 (7 mg/kg b.w.) by intratracheal instillation. The results showed that the body and kidney weights of the rats in the high-fat diet group were significantly increased relative to those with a normal diet, and changes in the intestinal microbes and metabolites induced by PM_2.5 were observed. Rats in the high-carbohydrate diet group had a significant response, and the diversity and richness indices of the flora were reduced (p < 0.05); additionally, intestinal Biffidobacterium and Lactobacillus were enriched, while many endogenous metabolites were found. Some amino acids derivatives and long-chain fatty acids were increased (p < 0.05). Both diet structure and PM_2.5 exposure can affect the composition of gut microbiota, and intestinal metabolites may be associated with cell membrane damage when a high-carbohydrate diet interacts with PM_2.5. This study considers multiple dietary factors to further supplement the evidence of intestinal damage via PM_2.5.

Lactic Acid Bacteria and Natural Product Complex Ameliorates Ovalbumin-Induced Airway Hyperresponsiveness in Mice

The incidence of respiratory diseases, such as asthma, has substantially increased in recent times owing to environmental changes, such as air pollution. Induction of a chronic inflammatory response begins with production of biologically active mediators from the airway epithelium, which attracts and recruits inflammatory cells into the lung airway. In our previous study, we confirmed that Lactobacillus casei HY2782 and Bifidobacterium animalis spp. lactis HY8002 could improve lung inflammation in the COPD animal model. In this study, we investigated the effect of the HY2782 complex against airway hyperresponsiveness by using an ovalbumin (OVA)-induced animal model. An orally administered HY2782 complex on OVA-induced allergic asthma in a BALB/c mouse model was used. The present results showed that the HY2782 complex suppressed total immunoglobulin E in serum and bronchoalveolar lavage fluid (BALF). The cytokine production profile in BALF and serum revealed that the HY2782 complex showed reduced levels of Th2 cytokines among immune factors released due to the elevated allergic response. Levels of inflammatory mediators in BALF, MCP-1, MIP-2, and CXCL-9 were decreased by oral administration of the HY2782 complex. Lower numbers of eosinophils and neutrophils in BALF suggested that inflammation was ameliorated by the HY2782 complex. Histological observation of lung sections also showed infiltration of fewer cells. From results, we suggested that the HY2782 complex effectively responds to improvement of the immune response and airway hypersensitivity reaction because of the anti-inflammatory effect of the Pueraria lobata root extract and antioxidant effect of HY2782.

Nutraceuticals with anti-inflammatory and anti-oxidant properties as intervention for reducing the health effects of fine particulate matter: Potential and Prospects

Air pollution, especially particulate matter pollution adversely affects human health. A growing pool of evidence has emerged which underscores the potential of individual-level nutritional interventions in attenuating the adverse health impact of exposure to PM2.5. Although controlling emission and reducing the overall levels of air pollution remains the ultimate objective globally, the sustainable achievement of such a target and thus consequent protection of human health will require a substantial amount of time and concerted efforts worldwide. In the meantime, smaller-scale individual-level interventions that can counter the inflammatory or oxidative stress effects triggered by exposure to particulate matter may be utilized to ameliorate the health effects of PM2.5 pollution. One such intervention is incorporation of nutraceuticals in the diet. Here, we present a review of the evidence generated from various in vitro, in vivo and human studies regarding the effects of different anti-inflammatory and antioxidant nutraceuticals in ameliorating the health effects of particulate matter air pollution. The studies discussed in this review suggest that these nutraceuticals when consumed as a part of the diet, or as additional supplementation, can potentially negate the cellular level adverse effects of exposure to particulate pollution. The potential benefits of adopting a non-pharmacological diet-based approach to air pollution-induced disease management have also been discussed. We argue that before a nutraceuticals-based approach can be used for widespread public adoption, further research, especially human clinical trials, is essential to confirm the beneficial action of relevant nutraceuticals and to explore the safe limits of human supplementation and the risk of side effects. Future research should focus on systematically translating bench-based knowledge regarding nutraceuticals gained from in-vitro and in-vivo studies into clinically usable nutritional guidelines.

The Functional Properties of Lactobacillus casei HY2782 Are Affected by the Fermentation Time

Maintaining probiotic effectiveness represents the most important task for the development of functional foods. Gastrointestinal stability and intestinal adhesion properties comprise one criterion for probiotic selection. Here, we investigated the benefits of milk fermented with Lactobacillus casei HY2782 at different fermentation times. The probiotic strain used was L. casei HY2782 and the reference strain was L. casei ATCC393 for comparisons. The samples were fermented for 7 days at 30 °C. We determined the pH, CFU/mL, survival rate during simulated gastrointestinal digestion, adhesion ability to HT-29 cells, and gene expression of tight-junction proteins known to regulate intestinal permeability in Caco-2 cells. L. casei HY2782 exhibited significantly higher survival rates in simulated gastrointestinal digestion during long-term fermentation than L. casei ATCC393. The adhesion ability to HT-29 cells was significantly increased with L. casei HY2782 (3.3% to 8.7%) after 7 days of fermentation; however, only a slight increase was observed for L. casei ATCC393 (3.1% to 4.7%). In addition, L. casei HY2782 can significantly increase the expression of genes encoding tight-junction proteins during long-term fermentation of milk. In conclusion, we confirmed that long-term fermentation could be a novel manufacturing process for fermented milk containing L. casei HY2782 and showed the beneficial effects.