Potential Health-Promoting Benefits of Paraprobiotics, Inactivated Probiotic Cells

A Next-Generation Bacteria (Akkermansia muciniphila BAA-835) Presents Probiotic Potential Against Ovalbumin-Induced Food Allergy in Mice

Next-generation microorganisms have recently gained prominence in the scientific community, mainly due to their probiotic and postbiotic potentials. However, there are few studies that investigate these potentials in food allergy models. Therefore, the present study was designed to evaluate the probiotic potential of Akkermansia muciniphila BAA-835 in an ovalbumin food allergy (OVA) model and also analyse possible postbiotic potential. To access the probiotic potential, clinical, immunological, microbiological, and histological parameters were evaluated. In addition, the postbiotic potential was also evaluated by immunological parameters. Treatment with viable A. muciniphila was able to mitigate weight loss and serum levels of IgE and IgG1 anti-OVA in allergic mice. In addition, the ability of the bacteria to reduce the injury of the proximal jejunum, the eosinophil and neutrophil influx, and the levels of eotaxin-1, CXCL1/KC, IL4, IL6, IL9, IL13, IL17, and TNF, was clear. Furthermore, A. muciniphila was able to attenuate dysbiotic signs of food allergy by mitigating Staphylococcus levels and yeast frequency in the gut microbiota. In addition, the administration of the inactivated bacteria attenuated the levels of IgE anti-OVA and eosinophils, indicating its postbiotic effect. Our data demonstrate for the first time that the oral administration of viable and inactivated A. muciniphila BAA-835 promotes a systemic immunomodulatory protective effect in an in vivo model of food allergy to ovalbumin, which suggests its probiotic and postbiotic properties.

Defining a vitamin A5/X specific deficiency - vitamin A5/X as a critical dietary factor for mental health

A healthy and balanced diet is an important factor to assure a good functioning of the central and peripheral nervous system. Retinoid X receptor (RXR)-mediated signaling was identified as an important mechanism of transmitting major diet-dependent physiological and nutritional signaling such as the control of myelination and dopamine signalling. Recently, vitamin A5/X, mainly present in vegetables as provitamin A5/X, was identified as a new concept of a vitamin which functions as the nutritional precursor for enabling RXR-mediated signaling. The active form of vitamin A5/X, 9-cis-13,14-dehydroretinoic acid (9CDHRA), induces RXR-activation, thereby acting as the central switch for enabling various heterodimer-RXR-signaling cascades involving various partner heterodimers like the fatty acid and eicosanoid receptors/peroxisome proliferator-activated receptors (PPARs), the cholesterol receptors/liver X receptors (LXRs), the vitamin D receptor (VDR), and the vitamin A(1) receptors/retinoic acid receptors (RARs). Thus, nutritional supply of vitamin A5/X might be a general nutritional-dependent switch for enabling this large cascade of hormonal signaling pathways and thus appears important to guarantee an overall organism homeostasis. RXR-mediated signaling was shown to be dependent on vitamin A5/X with direct effects for beneficial physiological and neuro-protective functions mediated systemically or directly in the brain. In summary, through control of dopamine signaling, amyloid β-clearance, neuro-protection and neuro-inflammation, the vitamin A5/X - RXR - RAR - vitamin A(1)-signaling might be "one of" or even "the" critical factor(s) necessary for good mental health, healthy brain aging, as well as for preventing drug addiction and prevention of a large array of nervous system diseases. Likewise, vitamin A5/X - RXR - non-RAR-dependent signaling relevant for myelination/re-myelination and phagocytosis/brain cleanup will contribute to such regulations too. In this review we discuss the basic scientific background, logical connections and nutritional/pharmacological expert recommendations for the nervous system especially considering the ageing brain.

Heat-killed Limosilactobacillus reuteri ATCC PTA 6475 prevents bone loss in ovariectomized mice: A preliminary study

Osteoporosis is an important health problem that occurs due to an imbalance between bone formation and resorption. Hormonal deficiency post-menopause is a significant risk factor. The probiotic Limosilactobacillus reuteri has been reported to prevent ovariectomy (Ovx)-induced bone loss in mice and reduce bone loss in postmenopausal women. Despite the numerous health benefits of probiotics, as they are live bacteria, the administration is not risk-free for certain groups (e.g., neonates and immunosuppressed patients). We evaluated the effects of L. reuteri (ATCC PTA 6475) and its heat-killed (postbiotic) form on Ovx-induced bone loss. Adult female mice (BALB/c) were randomly divided into four groups: group C-control (sham); group OVX-C-Ovx; group OVX-POS-Ovx + heat-killed probiotic; group OVX-PRO-Ovx + probiotic. L. reuteri or the postbiotic was administered to the groups (1.3x109 CFU/day) by gavage. Bacterial morphology after heat treatment was accessed by scanning electron microscopy (SEM). The treatment started one week after Ovx and lasted 28 days (4 weeks). The animals were euthanized at the end of the treatment period. Bone microarchitecture and ileum Occludin and pro-inflammatory cytokines gene expression were evaluated by computed microtomography and qPCR techniques, respectively. The Ovx groups had lower percentage of bone volume (BV/TV) and number of bone trabeculae as well as greater total porosity compared to the control group. Treatment with live and heat-killed L. reuteri resulted in higher BV/TV and trabecular thickness than the Ovx group. The heat treatment caused some cell surface disruptions, but its structure resembled that of the live probiotic in SEM analysis. There were no statistical differences in Occludin, Il-6 and Tnf-α gene expression. Both viable and heat-killed L. reuteri prevented bone loss on ovariectomized mice, independently of gut Occludin and intestinal Il-6 and Tnf-α gene expression.

The effect of novel paraprobiotic cocktail on dextran sodium sulfate induced acute colitis control focusing on autophagy signaling pathway

PURPOSE

Paraprobiotics are a non-viable form of probiotics that are reported to provide significant health benefits. Nevertheless, little is known about the beneficial effects of paraprobiotics on inflammatory bowel disease. Although probiotics show potential as therapeutic agents for a range of diseases, including inflammatory bowel disease (IBD), there are certain risks associated with their use. These risks include toxin production, hemolytic potential, antibiotic resistance, and the need to analyze metabolic activities. Hence Using paraprobiotic with the lower aforementioned risk would therefore be the preferable option. Here, we conducted an in vivo study to evaluate the preventive effect of our native paraprobiotic cocktail against dextran sulfate sodium (DSS)-induced murine colitis by affecting the autophagy signaling pathway.

METHODS

Four-week-old male C57Bl/6 mice were randomly divided into three groups after a two-week acclimation period with normal standard laboratory food diet. Mice were administered PBS (PBS group as control), PBS along with DSS (DSS group, as a control), and a cocktail of paraprobiotics along with DSS (Para group). The severity of colitis, length and histopathology of the colon were evaluated. In addition, the expression of autophagy was assessed using real-time PCR.

RESULTS

The results showed that administration of the paraprobiotic cocktail to DSS-treated mice inhibited the severity of colitis symptoms, as evidenced by the inhibition of weight loss and DAI, as well as histopathological scores in the study colon, as well as shortening of colon length caused by DSS. In contrast to the DSS group, the cocktail was able to modulate inflammation through upregulation of autophagy-related genes (becline 1, atg5, atg7, atg12, and atg13).

CONCLUSION

Although there are some limitations in our investigation, such as the dosage and duration of treatments, our native paraprobiotic blend effectively prevented the advancement of colitis. This suggests that it plays a vital role in regulating inflammation and preventing colitis by promoting the autophagy mechanism in cases where the consumption of probiotics may have negative consequences.

Unraveling the role of probiotics in affecting the structure of monoglyceride gelled emulsions: A low-field 1H NMR study

The capacity of monoglyceride (MG) gelled emulsions (MEs) in protecting probiotic cells of Lacticaseibacillus rhamnosus against stresses suffered during food processing, storage, and human digestion has been recently demonstrated. These findings open new perspectives on the possible participation of probiotics in the stabilization of emulsion structure. To unravel this aspect, rheological analysis and Low-Field 1H NMR investigations were performed on MEs having different aqueous phases (water or skimmed milk) and stored for increasing time (1 and 14 days) at 4 °C. Loaded and unloaded samples were considered. Results highlighted that probiotics initially hindered the ability of MG to self-assemble in the multiphase environment, interacting in some way with MG crystalline lamellar structure, as confirmed by rheological and 1H NMR analysis. During storage, an increase of proton compartmentation was observed in loaded MEs indicating the role of probiotics in stabilizing MG structure at a molecular level. Such a result was more evident when the system was composed of milk, suggesting that the presence of milk-native components (i.e., lactose, proteins, and minerals) favored the cell-structure interactions. Such preliminary results could open new perspectives in considering probiotic cells as having an active role in the stabilization of food structure.

Benefits of heat-killed Lactobacillus acidophilus on growth performance, nutrient digestibility, antioxidant status, immunity, and cecal microbiota of rabbits

Introduction

Heat-killed probiotics, as a type of inactivated beneficial microorganisms, possess an extended shelf life and broader adaptability compared to their live counterparts. This study aimed to investigate the impact of heat-killed Lactobacillus acidophilus (L. acidophilus, LA) - a deactivated probiotic on the growth performance, digestibility, antioxidant status, immunity and cecal microbiota of rabbits.

Methods

Two hundred weaned Hyla rabbits were randomly allocated into five equal groups (CON, L200, L400, L600, and L800). Over a 28-day period, the rabbits were fed basal diets supplemented with 0, 200, 400, 600, and 800 mg/kg of heat-killed LA, respectively.

Results

Results revealed a significant reduction in the feed-to-gain ratio (F/G) in the L600 and L800 groups (p < 0.05). Additionally, the L800 group exhibited significantly higher apparent digestibility of crude fiber (CF) and crude protein (CP) (p < 0.05). Regarding digestive enzyme activities, enhanced trypsin and fibrinase activities were observed in the L600 and L800 groups (p < 0.05). Concerning the regulation of the body's antioxidant status, the L800 group demonstrated elevated levels of superoxide dismutase (SOD) and total antioxidant capacity (T-AOC) in both serum and ileal tissue (p < 0.05). In terms of immune capacity modulation, serum tumor necrosis factor-α (TNF-α) levels were significantly lower in the L600 and L800 groups (p < 0.05), while immunoglobulin A (IgA) and immunoglobulin M (IgM) levels were higher (p < 0.05). Additionally, the L800 group exhibited a substantial increase in secretory immunoglobulin A (SIgA) levels in the intestinal mucosa (p < 0.05). In comparison to the CON group, the L800 group exhibited a significant increase in the relative abundance of Phascolarctobacterium and Alistipes in the cecum (p < 0.05). Phascolarctobacterium demonstrated a positive correlation with SIgA (p < 0.05), IgM (p < 0.01), and Glutathione peroxidase (GSH-Px) (p < 0.05), while displaying a negative correlation with TNF-α levels (p < 0.05). Concurrently, Alistipes exhibited positive correlations with IgA (p < 0.05), IgM (p < 0.05), SIgA (p < 0.01), GSH-Px (p < 0.05), SOD (p < 0.05), and T-AOC (p < 0.01), and a negative correlation with TNF-α (p < 0.05).

Discussion

In conclusion, the dietary incorporation of 600 mg/kg and 800 mg/kg of heat-killed LA positively influenced the growth performance, nutrient digestibility, antioxidant status, immune capacity and cecal microbiota of rabbits. This highlights the potential benefits of utilizing heat-killed probiotics in animal nutrition.

Probiotics and Paraprobiotics: Effects on Microbiota-Gut-Brain Axis and Their Consequent Potential in Neuropsychiatric Therapy

Neuropsychiatric disorders are clinical conditions that affect cognitive function and emotional stability, often resulting from damage or disease in the central nervous system (CNS). These disorders are a worldwide concern, impacting approximately 12.5% of the global population. The gut microbiota has been linked to neurological development and function, implicating its involvement in neuropsychiatric conditions. Due to their interaction with gut microbial communities, probiotics offer a natural alternative to traditional treatments such as therapeutic drugs and interventions for alleviating neuropsychiatric symptoms. Introduced by Metchnikoff in the early 1900s, probiotics are live microorganisms that provide various health benefits, including improved digestion, enhanced sleep quality, and reduced mental problems. However, concerns about their safety, particularly in immunocompromised patients, warrant further investigation; this has led to the concept of "paraprobiotics", inactivated forms of beneficial microorganisms that offer a safer alternative. This review begins by exploring different methods of inactivation, each targeting specific cellular components like DNA or proteins. The choice of inactivation method is crucial, as the health benefits may vary depending on the conditions employed for inactivation. The subsequent sections focus on the potential mechanisms of action and specific applications of probiotics and paraprobiotics in neuropsychiatric therapy. Probiotics and paraprobiotics interact with gut microbes, modulating the gut microbial composition and alleviating gut dysbiosis. The resulting neuropsychiatric benefits primarily stem from the gut-brain axis, a bidirectional communication channel involving various pathways discussed in the review. While further research is needed, probiotics and paraprobiotics are promising therapeutic agents for the management of neuropsychiatric disorders.

The Role of Gut Microbiota and Leaky Gut in the Pathogenesis of Food Allergy

Food allergy (FA) is a growing public health concern, with an increasing prevalence in Western countries. Increasing evidence suggests that the balance of human gut microbiota and the integrity of our intestinal barrier may play roles in the development of FA. Environmental factors, including industrialization and consumption of highly processed food, can contribute to altering the gut microbiota and the intestinal barrier, increasing the susceptibility to allergic sensitization. Compositional and functional alterations to the gut microbiome have also been associated with FA. In addition, increased permeability of the gut barrier allows the translocation of allergenic molecules, triggering Th2 immune responses. Preclinical and clinical studies have highlighted the potential of probiotics, prebiotics, and postbiotics in the prevention and treatment of FA through enhancing gut barrier function and promoting the restoration of healthy gut microbiota. Finally, fecal microbiota transplantation (FMT) is now being explored as a promising therapeutic strategy to prevent FA in both experimental and clinical studies. In this review article, we aim to explore the complex interplay between intestinal permeability and gut microbiota in the development of FA, as well as depict potential therapeutic strategies.

Production of snack bar enriched with paraprobiotics grown in banana peel medium, nutritional, sensory and quality parameters

Introduction

Objective: this research aims to develop a product with high sensory and nutritional quality to make paraprobiotics developed in banana peel consumable within the scope of waste evaluation. Methods: Lactobacillus plantarum and Lactobacillus casei probiotics were developed here by using banana peels as a medium, and paraprobiotics were obtained from these strains by the pasteurization method at 80 °C for 30 minutes. Two types of bars, with and without paraprobiotics, were produced, and the nutritional and sensory quality characteristics of the bars were examined. Results: bars with and without paraprobiotics showed similar properties in terms of energy, protein, carbohydrate, saturated fat, Ca, Mg, Zn, Fe, Na, and total sugar values and sensory criteria, but showed significantly different levels in terms of total fat, potassium, total fiber, total phenolic substance and antiradical activity values. Conclusion: bars with and without paraprobiotics are in the category of "protein added, protein source, or protein-containing", "high fiber", "low sodium" products.

Heat-inactivated Bifidobacterium adolescentis ameliorates colon senescence through Paneth-like-cell-mediated stem cell activation

Declined numbers and weakened functions of intestinal stem cells (ISCs) impair the integrity of the intestinal epithelium during aging. However, the impact of intestinal microbiota on ISCs in this process is unclear. Here, using premature aging mice (telomerase RNA component knockout, Terc-/-), natural aging mice, and in vitro colonoid models, we explore how heat-inactivated Bifidobacterium adolescentis (B. adolescentis) affects colon senescence. We find that B. adolescentis could mitigate colonic senescence-related changes by enhancing intestinal integrity and stimulating the regeneration of Lgr5+ ISCs via Wnt/β-catenin signaling. Furthermore, we uncover the involvement of Paneth-like cells (PLCs) within the colonic stem-cell-supporting niche in the B. adolescentis-induced ISC regeneration. In addition, we identify soluble polysaccharides (SPS) as potential effective components of B. adolescentis. Overall, our findings reveal the role of heat-inactivated B. adolescentis in maintaining the ISCs regeneration and intestinal barrier, and propose a microbiota target for ameliorating colon senescence.

Heat-Killed Lactobacillus rhamnosus ATCC 7469 Improved UVB-Induced Photoaging Via Antiwrinkle and Antimelanogenesis Impacts

Exposure of ultraviolet B (UVB) radiation is the main factor from the environment to cause skin photoaging. Lactobacillus rhamnosus ATCC 7469, is a probiotic strain with a good track record for enhancing human health. The present study conducted the impacts of heat-killed L. rhamnosus ATCC 7469 (RL) on photoaging in vitro using mouse skin fibroblast (MSF) cells and human epidermal melanocytes (HEM) exposed to UVB. The results showed that (1) RL-protected UVB-induced cytotoxicity relating to absorb UVB and reduce DNA damage. (2) RL exerted the antiwrinkle impact involved in two aspects. Firstly, RL downregulated MMP-1, 2, 3 expressions associating with MAPK signaling, resulting in the increased the protein expression of COL1A1, further booting type I collagen abundant thereby promoting the antiwrinkle impact in MSF cells. Secondly, RL reduced ROS content, further decreasing oxidative damage relating to Nrf2/Sirt3/SOD2 signaling, thereby promoting the antiwrinkle impact in MSF cells. (3) RL suppressed tyrosinase and TYRP-2 activity and/or levels associating with PKA/CREB/MITF signaling, thereby promoting antimelanogenesis impact in HEM cells. In conclusion, our findings suggest that RL could reduce photoaging caused by UVB via antiwrinkle and antimelanogenesis properties and may be a potential antiphotoaging beneficial component, which is applied in the cosmetic industry.

Plants against cancer: the immune-boosting herbal microbiome: not of the plant, but in the plant. Basic concepts, introduction, and future resource for vaccine adjuvant discovery

The presence of microorganism communities (MOCs) comprised of bacteria, fungi, archaea, algae, protozoa, viruses, and the like, are ubiquitous in all living tissue, including plant and animal. MOCs play a significant role in establishing innate and acquired immunity, thereby influencing susceptibility and resistance to disease. This understanding has fostered substantial advancements in several fields such as agriculture, food science/safety, and the development of vaccines/adjuvants, which rely on administering inactivated-attenuated MOC pathogens. Historical evidence dating back to the 1800s, including reports by Drs Busch, Coley, and Fehleisen, suggested that acute febrile infection in response to "specific microbes" could trigger spontaneous tumor remission in humans. This discovery led to the purposeful administration of the same attenuated strains, known as "Coley's toxin," marking the onset of the first microbial (pathogen) associated molecular pattern (MAMPs or PAMPs)-based tumor immunotherapy, used clinically for over four decades. Today, these same MAMPS are consumed orally by billions of consumers around the globe, through "specific" mediums (immune boosting "herbal supplements") as carriers of highly concentrated MOCs accrued in roots, barks, hulls, sea algae, and seeds. The American Herbal Products Association (AHPA) mandates microbial reduction in botanical product processing but does not necessitate the removal of dead MAMP laden microbial debris, which we ingest. Moreover, while existing research has focused on the immune-modulating role of plant phytochemicals, the actual immune-boosting properties might instead reside solely in the plant's MOC MAMP laden biomass. This assertion is logical, considering that antigenic immune-provoking epitopes, not phytochemicals, are known to stimulate immune response. This review explores a neglected area of research regarding the immune-boosting effects of the herbal microbiome - a presence which is indirectly corroborated by various peripheral fields of study and poses a fundamental question: Given that food safety focuses on the elimination of harmful pathogens and crop science acknowledges the existence of plant microbiomes, what precisely are the immune effects of ingesting MAMPs of diverse structural composition and concentration, and where are these distributed in our botanicals? We will discuss the topic of concentrated edible MAMPs as acid and thermally stable motifs found in specific herbs and how these would activate cognate pattern recognition receptors (PPRs) in the upper gut-associated lymphoid tissue (GALT), including Peyer's patches and the lamina propria, to boost antibody titers, CD8+ and CD4+ T cells, NK activity, hematopoiesis, and facilitating M2 to M1 macrophage phenotype transition in a similar manner as vaccines. This new knowledge could pave the way for developing bioreactor-grown/heat-inactivated MOC therapies to boost human immunity against infections and improve tumor surveillance.

Lactobacillus Probiotic Strains Differ in Their Ability to Adhere to Human Lung Epithelial Cells and to Prevent Adhesion of Clinical Isolates of Pseudomonas aeruginosa from Cystic Fibrosis Lung

The field of probiotic applications is rapidly expanding, including their use for the control of respiratory tract infections. Nevertheless, probiotics ability to colonize the lung environment and to compete with pulmonary pathogens is still a poorly investigated research area. In this study, we aimed to evaluate the adhesion ability of a number of commercial probiotic strains to the human lung epithelial cell line A549. Furthermore, we assessed probiotic ability to prevent host cell adhesion of one of the major lung pathogens in cystic fibrosis, Pseudomonas aeruginosa, and to reduce the pathogen-induced inflammatory response of human peripheral blood mononuclear cells (PBMCs) in terms of cytokine release. Lactobacillus acidophilus displayed the highest adhesion ability to A549 cells evaluated as percent of adhered bacteria compared to the inoculum. In agreement with such an observation, L. acidophilus was the most efficient in preventing adhesion to A549 cells of a P. aeruginosa isolate from CF sputum. Three-color fluorescence labeling of A549 cells, P. aeruginosa, and L. acidophilus, and confocal microcopy image analyses revealed a likely exclusion effect played by both live and UV-killed L. acidophilus towards P. aeruginosa. Such results were confirmed by CFU count. When co-cultured with PBMCs, both live and UV-killed L. acidophilus reduced the amount of IL-1β and IL-6 in culture supernatants in a statistically significant manner. Overall, the results obtained point to L. acidophilus as an interesting candidate for further studies for a potential aerogenous administration to control P. aeruginosa infections.

Production of Reactive Oxygen (ROS) and Nitrogen (RNS) Species in Macrophages J774A.1 Activated by the Interaction between Two Escherichia coli Pathotypes and Two Probiotic Commercial Strains

Probiotics play an important role against infectious pathogens, such as Escherichia coli (E. coli), mainly through the production of antimicrobial compounds and their immunomodulatory effect. This protection can be detected both on the live probiotic microorganisms and in their inactive forms (paraprobiotics). Probiotics may affect different cells involved in immunity, such as macrophages. Macrophages are activated through contact with microorganisms or their products (lipopolysaccharides, endotoxins or cell walls). The aim of this work was the evaluation of the effect of two probiotic bacteria (Escherichia coli Nissle 1917 and Bifidobacterium animalis subsp. lactis HN019 on macrophage cell line J774A.1 when challenged with two pathogenic strains of E. coli. Macrophage activation was revealed through the detection of reactive oxygen (ROS) and nitrogen (RNS) species by flow cytometry. The effect varied depending on the kind of probiotic preparation (immunobiotic, paraprobiotic or postbiotic) and on the strain of E. coli (enterohemorrhagic or enteropathogenic). A clear immunomodulatory effect was observed in all cases. A higher production of ROS compared with RNS was also observed.

Beyond probiotics: a narrative review on an era of revolution

Whether knowingly or unknowingly, humans have been consuming probiotic microorganisms through traditionally fermented foods for generations. Bacteria, like lactic acid bacteria, are generally thought to be harmless and produce many metabolites that are beneficial for human health. Probiotics offer a wide range of health benefits; however, their therapeutic usage is limited because they are living organisms. As a result, the focus on the health advantages of microbes has recently shifted from viable live probiotics to non-viable microbes made from probiotics. These newly emerging non-viable microbes include paraprobiotics, postbiotics, psychobiotics, nutribiotics, and gerobiotics. Their metabolites can boost physiological health and reveal the therapeutic effects of probiotics. This new terminology in microbes, their traits, and their applications are summarized in the present review.

Bifidobacterium longum subsp. longum 51A Attenuates Signs of Inflammation in a Murine Model of Food Allergy

Food allergy is a pathological condition that can lead to hives, swelling, gastrointestinal distress, cardiovascular and respiratory compromise, and even anaphylaxis. The lack of treatment resources emphasizes the necessity for new therapeutic strategies, and in this way, probiotics has been pointed out as an alternative, especially because of its immunomodulatory properties. The goal of this study was to evaluate the probiotic effect of Bifidobacterium longum subsp. longum 5^1A (BL5^1A) in a murine model of ovalbumin (OVA) food allergy, as well as to investigate the effect of the dose and viability of the bacteria on the proposed model. For this purpose, the probiotic effect was assessed by clinical, immunological, and histological parameters in mice treated or not with the BL5^1A and sensitized or not with OVA. Oral administration of BL5^1A prevented weight loss and reduced serum levels of IgE anti-OVA and of sIgA in the intestinal fluid. Also, it reduced the intestinal permeability, proximal jejunum damage, recruitment of eosinophils and neutrophils, and levels of eotaxin-1, CXCL1/KC, IL4, IL5, IL6, IL13, and TNF. Furthermore, the treatment was able to increase the levels of IL10. Investigating different doses administered, the level of 10⁸ CFU showed the best results in terms of protective effect. In addition, the administration of the inactivated bacteria did not present any beneficial effect. Results demonstrate that BL5^1A promotes a systemic immunomodulatory protective effect in a murine model of food allergy that depends on the dose and viability of the bacteria, suggesting its use as probiotic in such disease.

Evaluation of the potential anti-soybean allergic activity of different forms of Lactobacillus delbrueckii subsp. bulgaricus based on cell model in vitro

Live, inactivated Lactobacillus or their metabolites have various beneficial functions, which may alleviate food allergy. This study aimed to investigate the intervention effects of three forms of Lactobacillus delbrueckii subsp. bulgaricus (Ld) on cell degranulation, intestinal barrier function, and intestinal mucosal immunity against soybean allergy. First, the intervention effect of Ld on cell degranulation was investigated using the KU812 cell degranulation model. Then, the Caco-2 cell inflammation model was used to evaluate their anti-inflammatory capacity, and the cell monolayer model was constructed to test the protective effects of different forms of Ld on the intestinal barrier. Finally, mesenteric lymph node (MLN) cells from mice were used to assess the ability of different forms of Ld to regulate the balance of cytokines associated with food allergy in the immune tissue of the intestinal mucosa. Results showed that live bacteria and heat-inactivated bacteria could inhibit the degranulation of KU812 cells, mainly by significantly inhibiting the release of histamine, IL-6 and TNF-α. Both live bacteria and heat-inactivated bacteria could also suppress the increase of IL-6 and IL-8 in Caco-2 cells induced by lipopolysaccharide (LPS). The culture supernatant of bacteria and live bacteria showed better ability to maintain the integrity and permeability of the intestinal epithelial barrier. In addition, heat-inactivated bacteria could return the values of IFN-γ and IL-10 to normal levels and restore the balance of IFN-γ/IL-4, thereby reversing the immune deviation of MLN cells. Therefore, three forms of Ld have potential for the treatment of soybean allergy.

Effects of paraprobiotic as replacements for antibiotic on performance, immunity, gut health and carcass characteristics in broiler chickens

This study sought to determine the effects of dietary paraprobiotic (PPB) on broiler chicken performance, immunity, gut health, and carcass traits. A total of 240 day-old CARIBRO Vishal commercial broiler chicks of identical body weight randomly divided into six treatment groups, each with five replicates and eight chicks in each replicate. Six dietary treatments were preapared: T₁ = (control diet), T₂ = T₁ + 0.02% (w/v) chlortetracycline (CTC), T₃ = T₁ + 0.2% (w/v) PPB, T₄ = T₁ + 0.4% (w/v) PPB, T₅ = T₁ + 0.6% (w/v) PPB and T₆ = T₁ + 0.8% (w/v) PPB, respectively. Body weight gain (BWG) significantly (P ≤ 0.05) increased in the T₅ (0.6% PPB) and T₆ (0.8% PPB) group. At the same time the feed intake significantly (P ≤ 0.05) decreased and the feed conversion ratio (FCR) significantly (P ≤ 0.05) improved in T₅ and T₆ group. There was a significant (P ≤ 0.05) increase in cell-mediated immunity and haem-agglutination titre (HA titre) in the 0.6% and 0.8% PPB supplemented groups compare to the control group (T₁). The percentage of carcass traits and organ weights did not significantly differ between the PPB-supplemented and control groups, but the percentage of live weight in cut up parts showed a significant improvement (P ≤ 0.05) in the PPB-supplemented group. At 42 days, villus height, width, and crypt depth all significantly (P ≤ 0.05) increased in the groups supplemented with 0.6 and 0.8% para-probiotics (T₅ and T₆). The results show that para-probiotics can be added to broiler diets at a rate of 0.6% (w/v) to enhance performance, immunity, gut health, and breast yield. The para-probiotic may therefore be a useful substitution for antibiotic growth promoters in the diet of chickens.

Recent advances and potentiality of postbiotics in the food industry: Composition, inactivation methods, current applications in metabolic syndrome, and future trends

Postbiotics are defined as "preparation of inanimate microorganisms and/or their components that confers a health benefit on the host". Postbiotics have unique advantages over probiotics, such as stability, safety, and wide application. Although postbiotics are research hotspots, the research on them is still very limited. This review provides comprehensive information on the scope of postbiotics, the preparation methods of inanimate microorganisms, and the application and mechanisms of postbiotics in metabolic syndrome (MetS). Furthermore, the application trends of postbiotics in the food industry are reviewed. It was found that postbiotics mainly include inactivated microorganisms, microbial lysates, cell components, and metabolites. Thermal treatments are the main methods to prepare inanimate microorganisms as postbiotics, while non-thermal treatments, such as ionizing radiation, ultraviolet light, ultrasound, and supercritical CO2, show great potential in postbiotic preparation. Postbiotics could ameliorate MetS through multiple pathways including the modulation of gut microbiota, the enhancement of intestinal barrier, the regulation of inflammation and immunity, and the modulation of hormone homeostasis. Additionally, postbiotics have great potential in the food industry as functional food supplements, food quality improvers, and food preservatives. In addition, the SWOT analyses showed that the development of postbiotics in the food industry exists both opportunities and challenges.

Novel Horizons in Postbiotics: Lactobacillaceae Extracellular Vesicles and Their Applications in Health and Disease

Lactobacillus probiotics contained in dietary supplements or functional foods are well-known for their beneficial properties exerted on host health and diverse pathological situations. Their capacity to improve inflammatory bowel disease (IBD) and regulate the immune system is especially remarkable. Although bacteria-host interactions have been thought to occur directly, the key role that extracellular vesicles (EVs) derived from probiotics play on this point is being unveiled. EVs are lipid bilayer-enclosed particles that carry a wide range of cargo compounds and act in different signalling pathways. Notably, these EVs have been recently proposed as a safe alternative to the utilisation of live bacteria since they can avoid the possible risks that probiotics may entail in vulnerable cases such as immunocompromised patients. Therefore, this review aims to give an updated overview of the existing knowledge about EVs from different Lactobacillus strains, their mechanisms and effects in host health and different pathological conditions. All of the information collected suggests that EVs could be considered as potential tools for the development of future novel therapeutic approaches.

Heat-Killed Lacticaseibacillus paracasei Ameliorated UVB-Induced Oxidative Damage and Photoaging and Its Underlying Mechanisms

Ultraviolet B (UVB) radiation is a major environmental causative factor of skin oxidative damage and photoaging. Lacticaseibacillus paracasei is a well-known probiotic strain that can regulate skin health. The present study investigated the effects of heat-killed Lacticaseibacillus paracasei (PL) on UVB linked oxidative damage and photoaging in skin cells (Normal human dermal fibroblast (NHDF) cells and B16F10 murine melanoma cells). Results demonstrated that: (1) PL prevented UVB-induced cytotoxicity relating to decreased DNA damage in NHDF and B16F10 cells; (2) PL alleviated UVB-induced oxidative damage through increasing GSH content, as well as antioxidant enzyme activities and mRNA levels (except MnSOD activity and mRNA levels as well as CAT mRNA level) relating to the activation of Sirt1/PGC-1α/Nrf2 signaling in NHDF cells; (3) PL attenuated UVB-induced photoaging was noticed with a decrease in the percentage of SA-β-gal positive cells in NHDF cells model. Moreover, PL attenuated UVB-induced photoaging through exerting an anti-wrinkling effect by enhancing the type I collagen level relating to the inhibition (JNK, p38)/(c-Fos, c-Jun) of signaling in NHDF cells, and exerting an anti-melanogenic effect by suppressing tyrosinase and TYRP-1 activity and/or expressions relating to the inhibition of PKA/CREB/MITF signaling in B16F10 cells. In conclusion, PL could ameliorate UVB-induced oxidative damage and photoaging. Therefore, PL may be a potential antioxidant and anti-photoaging active ingredient for the cosmetic industry.

Anti-Tumor Effect of Heat-Killed Bifidobacterium bifidum on Human Gastric Cancer through Akt-p53-Dependent Mitochondrial Apoptosis in Xenograft Models

Paraprobiotics, inactivated microbial cells, regulate immune system and exhibit antioxidant and anti-inflammatory activities in patients with weakened immunity or the elderly. This study evaluated the anti-tumor effects of heat-killed Bifidobacterium and Lactobacillus on human gastric cancer MKN1 cells in vitro and in vivo in xenograft animal models. First, cytotoxicity and apoptosis in MKN1 cells of 11 different heat-killed Bifidobacterium or Lactobacillus strains were examined using the MTT assay or flow cytometry, respectively. Then, BALB/c nude mice xenograft animal models were implanted with human gastric cancer MKN1 cells and orally administered a selected single or a mixture of heat-killed bacterial strains to investigate their inhibitory effect on tumor growth. In addition, the expression of p-Akt, p53, Bax, Bak, cleaved caspase-9, -3, and PARP in the tumor tissues was analyzed using Western blotting assay or immunohistochemistry staining. The results show that heat-killed B. bifidum MG731 (MG731), L. reuteri MG5346 (MG5346), and L. rhamnosus MG5200 (MG5200) induced relatively greater apoptosis than other strains in MKN1 cells. Oral administration of a single dose or a mixture of MG731, MG5346, or MG5200 significantly delayed tumor growth, and MG731 had the most effective anti-tumor effect in the xenograft model. Protein expression of p-Akt, p53, Bax, cleaved caspase-3 and -9, and PARP in tumors derived from the xenograft model correlated with the results of the immunohistochemistry staining.

The Biotics Family: Current Knowledge and Future Perspectives in Metabolic Diseases

Globally, metabolic diseases such as obesity, type 2 diabetes mellitus and non-alcoholic fatty liver disease pose a major public health threat. Many studies have confirmed the causal relationship between risk factors and the etiopathogenesis of these diseases. Despite this, traditional therapeutic management methods such as physical education and diet have proven insufficient. Recently, researchers have focused on other potential pathways for explaining the pathophysiological variability of metabolic diseases, such as the involvement of the intestinal microbiota. An understanding of the relationship between the microbiome and metabolic diseases is a first step towards developing future therapeutic strategies. Currently, much attention is given to the use of biotics family members such as prebiotics (lactolose, soy oligosaccharides, galactooligosaccharides, xylooligosaccharides or inulin) and probiotics (genera Lactobacillus, Bifidobacterium, Lactococcus, Streptococcus or Enterococcus). They can be used both separately and together as synbiotics. Due to their direct influence on the composition of the intestinal microbiota, they have shown favorable results in the evolution of metabolic diseases. The expansion of the research area in the biotics family has led to the discovery of new members, like postbiotics. In the age of personalized medicine, their use as therapeutic options is of great interest to our study.

Evaluation of existing guidelines for their adequacy for the food and feed risk assessment of microorganisms obtained through synthetic biology

EFSA was asked by the European Commission to evaluate synthetic biology (SynBio) developments for agri-food use in the near future and to determine whether or not they are expected to constitute potential new hazards/risks. Moreover, EFSA was requested to evaluate the adequacy of existing guidelines for risk assessment of SynBio and if updated guidance is needed. The scope of this Opinion covers food and feed risk assessment, the variety of microorganisms that can be used in the food/feed chain and the whole spectrum of techniques used in SynBio. This Opinion complements a previously adopted Opinion with the evaluation of existing guidelines for the microbial characterisation and environmental risk assessment of microorganisms obtained through SynBio. The present Opinion confirms that microbial SynBio applications for food and feed use, with the exception of xenobionts, could be ready in the European Union in the next decade. New hazards were identified related to the use or production of unusual and/or new-to-nature components. Fifteen cases were selected for evaluating the adequacy of existing guidelines. These were generally adequate for assessing the product, the production process, nutritional and toxicological safety, allergenicity, exposure and post-market monitoring. The comparative approach and a safety assessment per se could be applied depending on the degree of familiarity of the SynBio organism/product with the non-genetically modified counterparts. Updated guidance is recommended for: (i) bacteriophages, protists/microalgae, (ii) exposure to plant protection products and biostimulants, (iii) xenobionts and (iv) feed additives for insects as target species. Development of risk assessment tools is recommended for assessing nutritional value of biomasses, influence of microorganisms on the gut microbiome and the gut function, allergenic potential of new-to-nature proteins, impact of horizontal gene transfer and potential risks of living cell intake. A further development towards a strain-driven risk assessment approach is recommended.

Heat-inactivated Lacticaseibacillus paracasei N1115 alleviates the damage due to brain function caused by long-term antibiotic cocktail exposure in mice

Critical development period of intestinal microbiota occurs concurrently with brain development, and their interaction is influenced by the microbiota–gut–brain axis. This study examined how antibiotics exposure affected gut microbiota and brain development and analyzed the possible benefits of heat-inactivated Lacticaseibacillus paracasei N1115 (N1115). Thirty neonatal male mice were randomly divided into three groups and treated with sterilized water (control), an antibiotic cocktail (Abx), or antibiotics plus heat-inactivated N1115 (Abx + N1115) for 84 days. We found that while the mRNA levels of GABA_Aα1, GABA_b1, and glucocorticoid receptor (GR) in the hippocampus and brain-derived neurotrophic factor (BDNF), GABA_Aα1, GABA_b1, and nerve growth factor (NGF) in the prefrontal cortex were higher, the mRNA levels of 5-HT_1A were lower in the Abx group. The Abx + N1115 group had lower mRNA levels of GABA_Aα1, GABA_b1, and GR in the hippocampus and BDNF, GABA_b1, and NGF in the prefrontal cortex than the Abx group. The latency period was longer in the Morris water maze test while longer rest time was seen in tail suspension test in the Abx group than the control and Abx + N1115 groups. In the open field test, the moving time and distance of the Abx group were reduced. Further, the alpha-diversity indexes of the Abx and Abx + N1115 groups were significantly lower than the control. Further, long-term exposure to antibiotics disrupted the intestinal microbiota as evidenced by decreased Bacteroides, Firmicutes, and Lactobacillus, and increased Proteobacteria and Citrobacter. However, N1115 significantly decreased the abundance of Citrobacter when compared with those in the Abx group. These results indicate that antibiotics can substantially damage the intestinal microbiota and cognitive function, causing anxiety and depression, which can be alleviated by heat-inactivated N1115 via modulation of the microbiota–gut–brain axis.

An insight into the health beneficial of probiotics dairy products: a critical review

Probiotic dairy products satisfy people's pursuit of health, and are widely favored because of their easy absorption, high nutritional value, and various health benefits. However, its effectiveness and safety are still controversial. This proposal aims to analyze the effect of probiotics on the quality characteristics of dairy products, clarify a series of physiological functions of probiotic dairy products and critically evaluate the effectiveness and safety of probiotic dairy products. Also, dairy products containing inactivated microorganisms were compared with probiotic products. The addition of probiotics enables dairy products to obtain unique quality characteristics, and probiotic dairy products have better health-promoting effects. This review will promote the further development of probiotic dairy products, provide directions for the research and development of probiotic-related products, and help guide the general public to choose and purchase probiotic fermentation products.

Probiotics in Citrus Fruits Products: Health Benefits and Future Trends for the Production of Functional Foods—A Bibliometric Review

The relationship between food and human health drives the search for knowledge of food components that are related to these benefits. The scientific community shows a growing interest in the knowledge of the interactions between components of citrus fruits and probiotics to develop ways to improve the quality of the food produced. In this bibliometric review, a study of scientific publications is carried out on the potential of probiotics in citrus fermentation, addressing the importance and future trends of plant-based products in the functional food group as an alternative to the dairy market. The review process of the articles initially took place with a bibliometric analysis and was followed by a literature review. The Scopus database was used in the search for articles, carried out in May 2021. The use of foods as carriers of probiotics is an alternative that has been growing and the surveys evaluated show the desire to diversify the probiotics available on the market. In addition, it was observed that citrus fruits have great potential for the development of functional foods due to their high acceptability and possibilities of development and application in various products.

How to Improve Health with Biological Agents-Narrative Review

The proper functioning of the human organism is dependent on a number of factors. The health condition of the organism can be often enhanced through appropriate supplementation, as well as the application of certain biological agents. Probiotics, i.e., live microorganisms that exert a beneficial effect on the health of the host when administered in adequate amounts, are often used in commonly available dietary supplements or functional foods, such as yoghurts. Specific strains of microorganisms, administered in appropriate amounts, may find application in the treatment of conditions such as various types of diarrhoea (viral, antibiotic-related, caused by Clostridioides difficile), irritable bowel syndrome, ulcerative colitis, Crohn’s disease, or allergic disorders. In contrast, live microorganisms capable of exerting influence on the nervous system and mental health through interactions with the gut microbiome are referred to as psychobiotics. Live microbes are often used in combination with prebiotics to form synbiotics, which stimulate growth and/or activate the metabolism of the healthy gut microbiome. Prebiotics may serve as a substrate for the growth of probiotic strains or fermentation processes. Compared to prebiotic substances, probiotic microorganisms are more tolerant of environmental conditions, such as oxygenation, pH, or temperature in a given organism. It is also worth emphasizing that the health of the host may be influenced not only by live microorganisms, but also by their metabolites or cell components, which are referred to as postbiotics and paraprobiotics. This work presents the mechanisms of action employed by probiotics, prebiotics, synbiotics, postbiotics, paraprobiotics, and psychobiotics, together with the results of studies confirming their effectiveness and impact on consumer health.

A new horizon of precision medicine: combination of the microbiome and extracellular vesicles

Over several decades, the disease pattern of intractable disease has changed from acute infection to chronic disease accompanied by immune and metabolic dysfunction. In addition, scientific evidence has shown that humans are holobionts; of the DNA in humans, 1% is derived from the human genome, and 99% is derived from microbial genomes (the microbiome). Extracellular vesicles (EVs) are lipid bilayer-delimited nanoparticles and key messengers in cell-to-cell communication. Many publications indicate that microbial EVs are both positively and negatively involved in the pathogenesis of various intractable diseases, including inflammatory diseases, metabolic disorders, and cancers. Microbial EVs in feces, blood, and urine show significant differences in their profiles between patients with a particular disease and healthy subjects, demonstrating the potential of microbial EVs as biomarkers for disease diagnosis, especially for assessing disease risk. Furthermore, microbial EV therapy offers a variety of advantages over live biotherapeutics and human cell EV (or exosome) therapy for the treatment of intractable diseases. In summary, microbial EVs are a new tool in medicine, and microbial EV technology might provide us with innovative diagnostic and therapeutic solutions in precision medicine.

The tiny membrane-bound vesicles containing various biomolecules that the organisms comprising our microbiome release could offer a powerful tool for precision medicine. Our bodies are home to trillions of microbes, which interact closely with our tissues to maintain a healthy physiological environment. Yoon-Keun Kim of the Institute of MD Healthcare, Seoul, South Korea, and colleagues have reviewed current research into the extracellular vesicles that these microbes use to communicate with other microbes and their human hosts. The authors note that these vesicles affect tissues throughout the body, and their activities have been linked to various disorders including asthma, Crohn’s disease and cancer. A deeper understanding of how these vesicles prevent or accelerate various conditions in different individuals could yield useful new diagnostic biomarkers and provide the foundation for interventions that are optimized for each patient.

Effect of Probiotics on Psychiatric Symptoms and Central Nervous System Functions in Human Health and Disease: A Systematic Review and Meta-Analysis

Background: The gut microbiota impacts on central nervous system (CNS) function via the microbiota–gut–brain axis. Thus, therapeutics targeting the gut microbiota such as probiotics have the potential for improving mental health. This meta-analysis synthesizes the evidence regarding the impacts of probiotics on psychological well-being, psychiatric symptoms and CNS functioning. Methods: The Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were applied for executing this review using the databases PubMed, Web of Science and Cochrane Library. The data were summarized at qualitative and quantitative level. Results: Fifty-four randomized placebo-controlled studies were included, of which 30 were eligible for meta-analysis. If investigated, the probiotics mostly exerted effects on CNS function. Most probiotics did not affect mood, stress, anxiety, depression and psychiatric distress when compared to placebo at the qualitative level. At quantitative level, depression and psychiatric distress improved slightly in the probiotic condition (depression: mean difference −0.37 (95% CI: −0.55, −0.20); p ≤ 0.0001; psychiatric distress: mean difference −0.33 (95% CI: −0.53, −0.13); p = 0.001). Conclusions: To date it is unclear to which extent and in which specific areas next generation probiotics selected and developed for their ability to improve psychiatric condition and potentially other CNS functions are promising.

Prebiotics, Probiotics, Synbiotics, Paraprobiotics and Postbiotic Compounds in IBD

The increasing incidence of inflammatory bowel diseases (IBD) and the increasing severity of the course of these diseases create the need for developing new methods of therapy. The gut microbiome is extensively studied as a factor influencing the development and course of IBD. The composition of intestinal microbiota can be relatively easily modified by diet (i.e., prebiotics, mainly dietary fibers) and bacterial supplementation using beneficial bacteria strains called probiotics. Additionally, the effects of the improved microbiome could be enhanced or gained by using paraprobiotics (non-viable, inactivated bacteria or their components) and/or postbiotics (products of bacterial metabolism or equal synthetic products that beneficially modulate immunological response and inflammation). This study summarizes the recent works on prebiotics, probiotics, synbiotics (products merging pre- and probiotics), paraprobiotics and postbiotics in IBD.

Effects of Feeding a Hypoallergenic Diet with a Nutraceutical on Fecal Dysbiosis Index and Clinical Manifestations of Canine Atopic Dermatitis

Simple Summary

The prevalence of canine atopic dermatitis in developed countries has been growing constantly over the last few decades. Genetic predisposition represents only part of the problem, and environmental factors are believed to be an important boost to the rapid rise in atopic dogs. Although a complete understanding of the gut–skin axis has not yet been achieved, a growing number of studies demonstrate a close relationship between gastrointestinal imbalance and skin diseases. The aim of this study was to assess the effect of a nutraceutical product on the Dysbiotic Index and skin lesions of atopic dogs.

Abstract

Background: an imbalance of the intestinal microbiota can cause health problems in the gastrointestinal tract and in other organs. Canine Atopic Dermatitis (CAD) is a genetically predisposed, inflammatory and pruritic allergic skin disease with multifactorial etiology and multimodal treatment. The aim of this study was to assess the effect of a nutraceutical product on Dysbiotic Index (DI) and the skin lesions of atopic dogs. Methods: a nutraceutical product was administered to 32 dogs with CAD. The product was associated with a standardized hypoallergenic diet for 60 days; the dietary regimen continued for 120 days, while ongoing therapies remained unchanged. Values of Visual Analogic Scale (VAS), Canine Atopic Dermatitis Lesional Index (CADLI) and DI were evaluated on day 0, 60, 120. Results: all the 32 dogs showed a statistically significant decrease (p < 0.001) to V60 of VAS and CADLI, which persisted and increased to V120 when diet alone was continued. The decrease in the DI value was also statistically significant (p < 0.001). Conclusion: the intake of nutraceutical associated with diet resulted in a decrease in the index of intestinal dysbiosis, with an improvement in the subjective severity of cutaneous lesions.

Effects of Heat-Killed Lactococcus lactis Strain Plasma on Skin Homeostasis-Related Genes and the Skin Microbiome among Healthy Adults: A Randomized Controlled Double-Blind Study

Lactococcus lactis subsp. lactis strain plasma (LC-plasma) is a bacterial strain that activates plasmacytoid dendritic cells and induces viral resistance genes via the TLR9/MyD88 pathway. We recently showed that oral administration of LC-plasma prevents skin infection by Staphylococcus aureus, possibly by activating skin immunity. In this study, we conducted a double-blind clinical trial to investigate the effect of oral administration of heat-killed LC-plasma on the skin microbiome, gene expression in the skin, and the skin condition of healthy volunteers. Seventy healthy volunteers were randomly assigned to receive either heat-killed LC-plasma or a placebo for eight weeks. Analysis of the skin microbiome by next-generation sequencing suggested that the alpha-diversity of the skin microbiome did not change during the test period in either group. However, the proportion of species that changed significantly during the test period was 10-fold smaller in the LC-plasma group than in the placebo group, suggesting that LC-plasma may maintain the skin microbiome. Quantitative PCR analysis indicated that tight-junction genes, such as CLDN1 and CLDN12, and the antimicrobial peptide gene BD3 were significantly up-regulated in the LC-plasma group but not in the placebo group. Our results suggest that administration of LC-plasma helps to maintain the skin microbiome and that it affects homeostasis-related genes.

Heat-killed Mycolicibacterium aurum Aogashima: An environmental nonpathogenic actinobacteria under development as a safe novel food ingredient

Over the last few decades, a wealth of evidence has formed the basis for "the Old Friends hypothesis" suggesting that, in contrast to the past, increasingly people are living in environments with limited and less diverse microbial exposure, with potential consequences for their health. Hence, including safe live or heat-killed microbes in the diet may be beneficial in promoting and maintaining human health. In order to assess the safety of microbes beyond the current use of standardized cultures and probiotic supplements, new approaches are being developed. Here, we present evidence for the safety of heat-killed Mycolicibacterium aurum Aogashima as a novel food, utilizing the decision tree approach developed by Pariza and colleagues (2015). We provide evidence that the genome of M. aurum Aogashima is free of (1) genetic elements associated with pathogenicity or toxigenicity, (2) transferable antibiotic resistance gene DNA, and (3) genes coding for antibiotics used in human or veterinary medicine. Moreover, a 90-day oral toxicity study in rats showed that (4) the no observed adverse effect level (NOAEL) was the highest concentration tested, namely 2000 μg/kg BW/day. We conclude that oral consumption of heat-killed M. aurum Aogashima is safe and warrants further evaluation as a novel food ingredient.

Skin Microbiome-The Next Frontier for Probiotic Intervention

The skin is the largest organ in the human body, and it orchestrates many functions that are fundamentally important for our survival. Although the skin might appear to present a relatively inhospitable or even hostile environment, a multitude of commensals and also some potentially pathogenic microorganisms have successfully adapted to survive and/or thrive within the diverse ecological niches created by the skin's topographical architecture. Dysbiosis within these microbial populations can result in the emergence and pathological progression of skin diseases. Unsurprisingly, this has led to a new focus of research both for the medical dermatology and cosmetic industries that is concerned with modulation of the skin microbiome to help address common microbially mediated or modulated conditions such as acne, body odour, and atopic dermatitis. This review presents an overview of our current understanding of the complex relationship of the skin with its microbiome and then introduces the concept of probiotic intervention for the management of microbial dysbiosis within the skin ecosystem.

The Effect of Probiotics on Quality of Life, Depression and Anxiety in Patients with Irritable Bowel Syndrome: A Systematic Review and Meta-Analysis

Background: Functional gastrointestinal disorders such as irritable bowel syndrome (IBS) report clinical improvement following probiotic therapy, but whether psychiatric comorbidity and quality-of-life in IBS improves directly or in directly is unknown. This meta-analysis synthesized the evidence regarding the effects of probiotics on quality of life (QoL), anxiety and depression in IBS. Methods: The review was executed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines using the databases PubMed, Web of Science and Cochrane Library. For QoL, the data were meta-analyzed, and for anxiety and depression a qualitative analysis was performed. Results: Thirty-five placebo-controlled studies were included of which 11 were eligible for meta-analysis. QoL improved with probiotic and placebo similarly, with the probiotic interventions slightly superior (mean QoL difference—0.36 (95% CI: 0.07, 0.64); p = 0.01). Anxiety and depression were similar between placebo and probiotic groups following therapy. Conclusion: For IBS, probiotic therapy improved QoL, but had no effects on anxiety and depression. However, the applied probiotics were not developed for selective effects on psyche and the brain. Therefore, it remains to be shown whether or not patients with IBS would benefit from second generation probiotics developed for these central effects (psychobiotics).

Lactobacillus sakei Pro-Bio65 Reduces TNF-α Expression and Upregulates GSH Content and Antioxidant Enzymatic Activities in Human Conjunctival Cells

Purpose

The study investigates the regulatory effects exhibited by lysate of Lactobacillus sakei pro-Bio65 (4%; L.SK) on the human conjunctival epithelial (HCE) cell line.

Methods

Trypan blue and methylthiazol tetrazolium (MTT) methods were used to assess cell growth and viability. Mitochondrial membrane potential was assessed by JC-1 staining and cytofluorimetric detection methods. The antioxidant pattern and the intracellular reactive oxygen species (ROS) levels were analyzed by spectrophotometric and spectrofluorimetric methods. NF-κB luciferase activity was quantified by luminometric detection. NF-κB nuclear translocation, as well as mitochondrial morphology, were investigated by immunofluorescence using confocal microscopy. Cytokines and COX2 expression levels were determined by Western blot analyses.

Results

This study demonstrates that L.SK exposure does not influence HCE cell proliferation and viability in vitro. L.SK paraprobiotic induces mild-low levels of intracellular ROS. It is coupled to changes in the mitochondrial membrane potential (ΔΨm), in a context of a regular mitochondrial-network organization. The negative modulation of tumor necrosis factor alpha (TNF-α) expression levels and rising antioxidant defense efficiency, mediated by the upregulation of glutathione (GSH) and increased antioxidant enzymatic activities, were observed.

Conclusions

This study demonstrates that L.SK empowers the antioxidant endogenous efficiency of HCE cells, by the upregulation of the GSH content and the enzymatic antioxidant pattern, and concurrently reduces TNF-α protein expression.

Translational Relevance

Although the obtained in vitro results should be confirmed by in vivo investigations, our data suggest the possibility of L.SK paraprobiotic application for promoting eye health, exploring its use as an endogen antioxidant system inducer in preventing and treating different oxidative stress-based, inflammatory, and age-related conditions.

Probiotics, Photobiomodulation, and Disease Management: Controversies and Challenges

In recent decades, researchers around the world have been studying intensively how micro-organisms that are present inside living organisms could affect the main processes of life, namely health and pathological conditions of mind or body. They discovered a relationship between the whole microbial colonization and the initiation and development of different medical disorders. Besides already known probiotics, novel products such as postbiotics and paraprobiotics have been developed in recent years to create new non-viable micro-organisms or bacterial-free extracts, which can provide benefits to the host with additional bioactivity to probiotics, but without the risk of side effects. The best alternatives in the use of probiotics and postbiotics to maintain the health of the intestinal microbiota and to prevent the attachment of pathogens to children and adults are highlighted and discussed as controversies and challenges. Updated knowledge of the molecular and cellular mechanisms involved in the balance between microbiota and immune system for the introspection on the gut-lung-brain axis could reveal the latest benefits and perspectives of applied photobiomics for health. Multiple interconditioning between photobiomodulation (PBM), probiotics, and the human microbiota, their effects on the human body, and their implications for the management of viral infectious diseases is essential. Coupled complex PBM and probiotic interventions can control the microbiome, improve the activity of the immune system, and save the lives of people with immune imbalances. There is an urgent need to seek and develop innovative treatments to successfully interact with the microbiota and the human immune system in the coronavirus crisis. In the near future, photobiomics and metabolomics should be applied innovatively in the SARS-CoV-2 crisis (to study and design new therapies for COVID-19 immediately), to discover how bacteria can help us through adequate energy biostimulation to combat this pandemic, so that we can find the key to the hidden code of communication between RNA viruses, bacteria, and our body.

Probiotics in the dairy industry-Advances and opportunities

The past two decades have witnessed a global surge in the application of probiotics as functional ingredients in food, animal feed, and pharmaceutical products. Among food industries, the dairy industry is the largest sector where probiotics are employed in a number of dairy products including sour/fermented milk, yogurt, cheese, butter/cream, ice cream, and infant formula. These probiotics are either used as starter culture alone or in combination with traditional starters, or incorporated into dairy products following fermentation, where their presence imparts many functional characteristics to the product (for instance, improved aroma, taste, and textural characteristics), in addition to conferring many health-promoting properties. However, there are still many challenges related to the stability and functionality of probiotics in dairy products. This review highlights the advances, opportunities, and challenges of application of probiotics in dairy industries. Benefits imparted by probiotics to dairy products including their role in physicochemical characteristics and nutritional properties (clinical and functional perspective) are also discussed. We transcend the traditional concept of the application of probiotics in dairy products and discuss paraprobiotics and postbiotics as a newly emerged concept in the field of probiotics in a particular relation to the dairy industry. Some potential applications of paraprobiotics and postbiotics in dairy products as functional ingredients for the development of functional dairy products with health-promoting properties are briefly elucidated.

Role of probiotics in prevention and treatment of enteric infections: a comprehensive review

Microorganisms that inhabits human digestive tract affect global health and enteric disorders. Previous studies have documented the effectiveness and mode of action of probiotics and classified as human-friendly biota and a competitor to enteric pathogens. Statistical studies reported more than 1.5 billion cases of gastrointestinal infections caused by enteric pathogens and their long-term exposure can lead to mental retardation, temporary or permanent physical weakness, and leaving the patient susceptible for opportunistic pathogens, which can cause fatality. We reviewed previous literature providing evidence about therapeutic approaches regarding probiotics to cure enteric infections efficiently by producing inhibitory substances, immune system modulation, improved barrier function. The therapeutic effects of probiotics have shown success against many foodborne pathogens and their therapeutic effectiveness has been exponentially increased using genetically engineered probiotics. The bioengineered probiotic strains are expected to provide a better and alternative approach than traditional antibiotic therapy against enteric pathogens, but the novelty of these strains also raise doubts about the possible untapped side effects, for which there is a need for further studies to eliminate the concerns relating to the use and safety of probiotics. Many such developments and optimization of the classical techniques will revolutionize the treatments for enteric infections.

Paraprobiotics: A New Perspective for Functional Foods and Nutraceuticals

Probiotics are live microorganisms that confer health benefits on the host. However, in recent years, several concerns on their use have been raised. In particular, industrial processing and storage of probiotic products are still technological challenges as these could severely impair cell viability. On the other hand, safety of live microorganisms should be taken into account, especially when administered to vulnerable people, such as the elderly and immunodeficient individuals. These drawbacks have enhanced the interest toward new products based on non-viable probiotics such as paraprobiotics and postbiotics. In particular, paraprobiotics, defined as "inactivated microbial cells (non-viable) that confer a health benefit to the consumer," hold the ability to regulate the adaptive and innate immune systems, exhibit anti-inflammatory, antiproliferative and antioxidant properties and exert antagonistic effect against pathogens. Moreover, paraprobiotics can exhibit enhanced safety, assure technological and practical benefits and can also be used in products suitable for people with weak immunity and the elderly. These features offer an important opportunity to prompt the market with novel functional foods or nutraceuticals that are safer and more stable. This review provides an overview of central issues on paraprobiotics and highlights the urgent need for further studies aimed at assessing safety and efficacy of these products and their mechanisms of action in order to support decisions of regulatory authorities. Finally, a definition is proposed that unambiguously distinguishes paraprobiotics from postbiotics.

Paraprobiotics obtained by six different inactivation processes: impacts on the biochemical parameters and intestinal microbiota of Wistar male rats

This study investigated the effects of feeding paraprobiotics obtained by six processes [heat, ultrasound, high pH, low pH, irradiation and supercritical carbon dioxide (CO₂)] on biochemical parameters and intestinal microbiota of Wistar male rats. Daily administration of paraprobiotics did not affect (p ≥ 0.05) the food intake, body weight, glucose and triglycerides levels, expression of antioxidant enzymes or thermal shock proteins in comparison to the control. Bifidobacterium lactis inactivated by irradiation and supercritical CO₂ decreased the total cholesterol levels in serum (p < 0.05). Bifidobacterium lactis inactivated by supercritical CO₂ increased the albumin and creatinine levels, while decreased the HDL-cholesterol levels (p < 0.05). Clostridiales (45.6-56%), Bacteroidales (31.9-44.2%) and Lactobacillales (3.9-7.8%) corresponded to the major orders in paraprobiotic groups. The properties of paraprobiotics are dependent on the method of inactivation, the intensity of the method employed and on the strain used.

Immuno-modulation by heat-killed Lacticaseibacillus paracasei MCC1849 and its application to food products

Probiotics are microorganisms that confer health benefits to host. Well-known examples include Bifidobacterium and Lactobacillus species. In recent years, interest in promoting our health with probiotics has grown as life expectancy and health awareness has increased. However, some concerns for safety and stability exist for these live organisms. Thus, “postbiotics” and “paraprobiotics,” non-viable heat-killed microbial cells or cell fractions that retain health benefits, are increasingly favored. Unfortunately, little information on clinical efficacy and mechanisms of action is available compared with many available probiotics. Lacticaseibacillus (previous name Lactobacillus) paracasei MCC1849 is a commonly used lactic acid bacterial strain in Japan that displays immuno-modulatory effects in humans in non-viable heat-killed form. This review discusses health benefits of heat-killed L. paracasei MCC1849 immune modulation and offers a theoretical basis for its mechanisms of action. We also discuss the feasibility of using heat-killed probiotics for application in food products.

Wheat-durum pasta added of inactivated Bifidobacterium animalis decreases glucose and total cholesterol levels and modulates gut microbiota in healthy rats

This study investigated the effects of consumption of wheat-durum pasta added of Bifidobacterium animalis inactivated by gamma-irradiation (paraprobiotic) on health and gut microbiota of rats. Twenty-one male rats were divided into three groups as follow: control (Control) receiving standard diet; pasta control (PC) receiving diet containing pasta, and paraprobiotic pasta Bifidobacterium-irradiated (PPBI), receiving paraprobiotic pasta. The serum levels of glucose and total cholesterol were reduced (p < 0.05) in PPBI when compared to the Control (p < 0.05). PPBI showed high abundance (p ˂ 0.05) of Firmicutes and Actinobacteria and a lower abundance of Bacteriodes compared to Control and PC. Besides, the PPBI showed high abundance (p ˂ 0.05) of Clostridiales, Lactobacillales; Bifidobacteriales, Bacillales, and Coriobacteriales in comparison to Control. Specific genera such as Bifibacterium, Lactobacillus, Ruminococcus, Allobaculum, and Blautia were more related to PPBI. Findings reveal wheat-durum pasta as a potential vehicle for delivering paraprobiotics B. animalis.

Shotgun metagenomic analysis reveals new insights into bacterial community profiles in tempeh

OBJECTIVE

Amplicon sequencing targeting 16S ribosomal RNA (rRNA) has been widely used to profile the microbial community from fermented food samples. However, polymerase chain reaction (PCR) steps on amplicon sequencing analysis and intragenomic heterogeneity within 16S rRNA are believed to contribute to bias in estimating microbial community composition. As potential paraprobiotics sources, a comprehensive profiling study of tempeh microbial ecology could contribute to tempeh product development. This study employed a shotgun metagenomic approach, where metagenome fragments from tempeh samples were sequenced directly for taxonomic and functional profiling analysis.

RESULTS

Taxonomic profiling showed that Proteobacteria, Firmicutes, and Bacteroidetes were the dominant phyla from the shotgun metagenomic analysis in all tempeh samples. In terms of composition, this shotgun metagenomic study revealed that Proteobacteria was the most abundant phylum. Functional profiling showed that iron complex outer-membrane recepter protein (KEGG ID: K02014) was the most transcribed gene based on this metagenomic analysis. The metagenome-assembled genomes (MAGs) results from the binning pipeline could reveal almost complete whole genome sequence of Lactobacillus fermentum, Enterococcus cecorum, Escherichia coli, Klebsiella pneumoniae, and Acinetobacter baumannii.