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

Heat-killed Lactiplantibacillus plantarum Shinshu N-07 exerts antiobesity effects in western diet-induced obese mice

AIMS

The aim of this study was to evaluate the antiobesity effects of heat-killed Lactiplantibacillus plantarum Shinshu N-07 (N-07) isolated from fermented Brassica rapa L.

METHODS AND RESULTS

Male mice were divided into three groups (n = 10/group); normal diet, western diet (WD), or WD + N-07 (N-07) group and administered each diet for 56 days. The N-07 group showed significant suppression of body weight gain and epididymal fat, perirenal fat, and liver weights compared with the WD group. Higher levels of fecal total cholesterol, triglyceride (TG), and free fatty acid (FFA) were observed in the N-07 group than in the WD group. The mRNA expression of the cholesterol transporter ATP-binding cassette transporter G5 (ABCG5) was significantly increased in the small intestine of N-07-fed mice compared with WD-fed mice. Moreover, N-07 supplementation significantly increased the mRNA expression of ABCG5 and ABCG8 in Caco-2 cells. Furthermore, the TG- and FFA-removal ability of N-07 was confirmed to evaluate its soybean oil- and oleic acid-binding capacities in in vitro experiments.

CONCLUSIONS

The antiobesity effects of N-07 might be due to its ability to promote lipid excretion by regulating cholesterol transporter expression and lipid-binding ability.

Streptococcus thermophilus: A Source of Postbiotics Displaying Anti-Inflammatory Effects in THP 1 Macrophages

In addition to traditional use in fermented dairy products, S. thermophilus also exhibits anti-inflammatory properties both in live and heat-inactivated form. Recent studies have highlighted that some hydrolysates from surface proteins of S. thermophilus could be responsible partially for overall anti-inflammatory activity of this bacterium. It was hypothesized that anti-inflammatory activity could also be attributed to peptides resulting from the digestion of intracellular proteins of S. thermophilus. Therefore, total intracellular proteins (TIP) from two phenotypically different strains, LMD-9 and CNRZ-21N, were recovered by sonication followed by ammonium sulphate precipitation. The molecular masses of the TIP of both strains were very close to each other as observed by SDS-PAGE. The TIP were fractionated by size exclusion fast protein liquid chromatography to obtain a 3-10 kDa intracellular protein (IP) fraction, which was then hydrolysed with pancreatic enzyme preparation, Corolase PP. The hydrolysed IP fraction from each strain exhibited anti-inflammatory activity by modulating pro-inflammatory mediators, particularly IL-1β in LPS-stimulated THP-1 macrophages. However, a decrease in IL-8 secretion was only observed with hydrolysed IP fraction from CNRZ-21N, indicating that strain could be an important parameter in obtaining active hydrolysates. Results showed that peptides from the 3-10 kDa IP fraction of S. thermophilus could therefore be considered as postbiotics with potential beneficial effects on human health. Thus, it can be used as a promising bioactive ingredient for the development of functional foods to prevent low-grade inflammation.

Frequently asked questions about the ISAPP postbiotic definition

The term postbiotic was defined by the International Scientific Association of Probiotics and Prebiotics (ISAPP) as "a preparation of inanimate microorganisms and/or their components that confers a health benefit on the host." Although the ISAPP definition is widely cited, some concerns were aired after publication, and alternative definitions of postbiotic, as well as different terms for inactivated microbes, have been previously suggested. This paper addresses questions about the ISAPP definition that have been raised in different forums, including scientific meetings, social media commentary and personal communications. We focus on the rationale, scope, wording, composition and commercial implementation, as well as what is expected of postbiotics regarding safety, efficacy, quantification and mechanisms of action. We hope that exploring these questions will further clarify the definition and its scope and support a common understanding of the concept of postbiotics.

Overview of anti-viral effects of probiotics via immune cells in pre-, mid- and post-SARS-CoV2 era

The COVID-19 outbreak has caused significant global changes and increased public awareness of SARS-CoV-2. Substantial progress in developing vaccines, enhancing sanitation practices, and implementing various measures to combat the virus, including the utilization of probiotics has been made. This comprehensive review examined the medical impact of clinically proven probiotics on infectious diseases, considering three crucial time periods: before (pre-), during (mid-), and after (post-) COVID-19 pandemic era. This review also showed a perspective on the use of probiotics to stimulate the innate immune system and prevent infectious diseases. In pre-COVID-19 era, several probiotic strains were found to be clinically effective in addressing gastrointestinal infectious diseases, the common cold and flu. However, the mechanism by which probiotics exerted their antiviral effects remained relatively unclear during that period. Nevertheless, probiotics, Lactococcus lactis strain Plasma (LC-Plasma), and others have gained attention for their unique ability to modulate the immune system and demonstrate antiviral properties. While some probiotics have shown promise in alleviating gastrointestinal symptoms linked to COVID-19, their direct effectiveness in treating or preventing COVID-19 progression has not yet been conclusively established. As we transition into the post-COVID-19 era, the relationship between COVID-19 and plasmacytoid dendritic cells (pDCs), a vital component of the innate immune system, has been gradually elucidated. These findings are now being applied in developing novel vaccines and treatments involving interferons and in immune activation research using probiotics as adjuvants, comparable to CpG-DNA through TLR9. The role of the local innate immune system, including pDCs, as the first line of defense against viral infections has gained increasing interest. Moving forward, insight of the immune system and the crosstalk between probiotics and the innate immune system is expected to highlight the role of probiotics in adjunctive immunoregulatory therapy. In combination with drug treatments, probiotics may play a more substantial role in enhancing immune responses. The immunoregulatory approach using probiotics such as LC-Plasma, which can induce anti-infectious factors such as interferons, holds promise as a viable therapeutic and prophylactic option against viral infectious diseases due to their good safety profile and protective efficacy.

Paraprobiotics: definition, manufacturing methods, and functionality

Probiotics are living microorganisms that are beneficial to the host, enhancing the immune response by promoting antibody production, regulating cytokine secretion, and stimulating T cells. However, probiotics have limitations in that they require viability control and have a short shelf life. Recently, the use of paraprobiotics has gained attention. These include dead bacterial cells, bacterial fractions, and cell lysate that have health benefits and are stable and safe for use. Paraprobiotics comprise molecules of bacterial cell wall compounds, such as peptidoglycans, teichoic acids, polysaccharides, and cell surface proteins. Paraprobiotics are manufactured by a diverse range of techniques, including thermal treatments, high pressure, ultraviolet rays, sonication, ionizing radiation, and pH modification. Their beneficial health effects include immunomodulatory, intestinal balancing, anticancer, and antimicrobial activities. Therefore, this review summarizes and discusses the manufacturing methods and bioavailability of paraprobiotics and suggests their potential health advantages.

A comprehensive review of Bifidobacterium spp: as a probiotic, application in the food and therapeutic, and forthcoming trends

Recently, more consumers are interested in purchasing probiotic food and beverage products that may improve their immune health. The market for functional foods and beverages that include Bifidobacterium is expanding because of their potential uses in both food and therapeutic applications. However, maintaining Bifidobacterium's viability during food processing and storage remains a challenge. Microencapsulation technique has been explored to improve the viability of Bifidobacterium. Despite the technical, microbiological, and economic challenges, the market potential for immune-supporting functional foods and beverages is significant. Additionally, there is a shift toward postbiotics as a solution for product innovation, a promising postbiotic product that can be incorporated into various food and beverage formats is also introduced in this review. As consumers become more health-conscious, future developments in the functional food and beverage market discussed in this review could serve as a reference for researchers and industrialist.

Effects of Heat-Killed Lacticaseibacillus paracasei MCC1849 on the Maintenance of Physical Condition in Healthy Adults: A Randomized, Double-Blind, Placebo-Controlled, Parallel-Group Study

We previously reported that the intake of heat-killed Lacticaseibacillus paracasei MCC1849 suppressed the onset of cold-like symptoms in healthy young women who were susceptible to colds. This study aimed to investigate the effects of MCC1849 on subjective symptoms of physical condition in healthy adults of a wide age range. In this randomized, double-blind, placebo-controlled, parallel-group study, 200 healthy adults were randomly divided into the MCC1849 group or placebo group. The participants received test powder with 50 billion MCC1849 cells or placebo powder without MCC1849 for 24 weeks. Subjective symptoms were assessed by diary scores. Analysis was performed on 183 participants (MCC1849 group; n = 91, placebo group; n = 92) in the per-protocol set. The number of days of stuffy nose and cold-like symptoms was significantly reduced in the MCC1849 group compared with the placebo group. In addition, the duration of stuffy nose, sore throat and cold-like symptoms was significantly lower in the MCC1849 group. No side effects were observed. Therefore, oral intake of MCC1849 suppressed subjective symptoms in healthy adults of a wide age range. These data suggest that MCC1849 may help maintain physical condition.

Heat-Killed L. helveticus Enhances Positive Mood States: A Randomized, Double-Blind, Placebo-Controlled Study

When mood states are impaired, daily life is severely disrupted. To maintain a specific mood state, both positive and negative moods must be controlled; however, methods to maintain a positive mood have not been fully established. Previous studies have suggested that heat-killed L. helveticus MCC1848 has the potential to improve positive moods. This study aimed to test the efficacy of heat-killed L. helveticus MCC1848 in maintaining and improving a positive mood with PANAS, a questionnaire specifically designed to assess positive and negative mood, as the primary endpoint. Healthy Japanese nursing students (n = 46) were randomized to receive heat-killed L. helveticus MCC1848 (5 billion/day) or placebo powder for four weeks. Mood state was assessed before and two and four weeks after the intervention began; ingestion of heat-killed L. helveticus MCC1848 significantly improved PANAS 'Positive Affect' compared to the placebo. These results indicate that heat-killed L. helveticus MCC1848 is effective in enhancing positive mood.

Heat-killed Lactobacillus helveticus improves mood states: a randomised, double-blind, placebo-controlled study

We investigated the effects of heat-killed Lactobacillus helveticus MCC1848 on daily mood states in healthy young adults. Participants (n=58) were randomised to receive heat-killed L. helveticus MCC1848 powder or placebo powder for 4 weeks. During the study period, adverse events were recorded in the participant diary. Mood states were assessed before and 2 and 4 weeks after initiation of the intervention. The primary outcomes were the shortened version of the Profile of Mood States 2 (POMS 2) scores. Secondary outcomes included other mood state (State-Trait Anxiety Inventory (STAI); visual analogue scale (VAS)), quality of life (acute form of the SF-36v2), sleep (Athens Insomnia Scale (AIS)) and fatigue (Chalder Fatigue Scale (CFS)) scores. Four weeks of heat-killed L. helveticus MCC1848 intake, compared to placebo, significantly improved the shortened version of the POMS 2 'friendliness' and the VAS 'relaxed' scores, which are two indicators of positive mood states. On the other hand, heat-killed L. helveticus MCC1848 intake had no significant effects on negative mood state items (e.g. anger, nervousness, confusion) assessed by the shortened version of the POMS 2, STAI and VAS. AIS and CFS scores also showed no significant differences. No adverse effects were observed with 4 weeks of heat-killed L. helveticus MCC1848 intake. These results suggest that daily consumption of heat-killed L. helveticus MCC1848 is safe and has the potential to improve positive mood states. UMIN Clinical Trial Registry: UMIN000043697.

Heat-Killed Lacticaseibacillus paracasei Repairs Lipopolysaccharide-Induced Intestinal Epithelial Barrier Damage via MLCK/MLC Pathway Activation

Intestinal epithelial barrier function is closely associated with the development of many intestinal diseases. Heat-killed Lacticaseibacillus paracasei (HK-LP) has been shown to improve intestinal health and enhance immunity. However, the function of HK-LP in the intestinal barrier is still unclear. This study characterized the inflammatory effects of seven HK-LP (1 μg/mL) on the intestinal barrier using lipopolysaccharide (LPS) (100 μg/mL)-induced Caco-2 cells. In this study, HK-LP 6105, 6115, and 6235 were selected, and their effects on the modulation of inflammatory factors and tight junction protein expression (claudin-1, zona occludens-1, and occludin) were compared. The effect of different cultivation times (18 and 48 h) was investigated in response to LPS-induced intestinal epithelial barrier dysfunction. Our results showed that HK-LP 6105, 6115, and 6235 improved LPS-induced intestinal barrier permeability reduction and transepithelial resistance. Furthermore, HK-LP 6105, 6115, and 6235 inhibited the pro-inflammatory factors (TNF-α, IL-1β, IL-6) and increased the expression of the anti-inflammatory factors (IL-4, IL-10, and TGF-β). HK-LP 6105, 6115, and 6235 ameliorated the inflammatory response. It inhibited the nuclear factor kappa B (NF-κB) signaling pathway-mediated myosin light chain (MLC)/MLC kinase signaling pathway by downregulating the Toll-like receptor 4 (TLR4)/NF-κB pathway. Thus, the results suggest that HK-LP 6150, 6115, and 6235 may improve intestinal health by regulating inflammation and TJ proteins. Postbiotics produced by these strains exhibit anti-inflammatory properties that can protect the intestinal barrier.

Implication of Paraprobiotics in Age-Associated Gut Dysbiosis and Neurodegenerative Diseases

Neurodegenerative diseases, including Alzheimer's and Parkinson's disease, are major age-related concerns in elderly people. Since no drug fully addresses the progression of neurodegenerative diseases, advance treatment strategies are urgently needed. Several studies have noted the senescence of immune system and the perturbation of gut microbiota in the aged population. In recent years, the role of gut microbiota has been increasingly studied in the manifestation of age-related CNS disorders. In this context, prebiotics, probiotics, and paraprobiotics are reported to improve the behavioural and neurobiological abnormalities in elderly patients. As live microbiota, prescribed in the form of probiotics, shows some adverse effects like sepsis, translocation, and horizontal gene transfer, paraprobiotics could be a possible alternative strategy in designing microbiome-based therapeutics. This review describes the health-beneficial effects of paraprobiotics in age-associated neurodegenerative diseases.

Postbiotics Derived from L. paracasei ET-22 Inhibit the Formation of S. mutans Biofilms and Bioactive Substances: An Analysis

Globally, dental caries is one of the most common non-communicable diseases for patients of all ages; Streptococcus mutans (S. mutans) is its principal pathogen. Lactobacillus paracasei (L. paracasei) shows excellent anti-pathogens and immune-regulation functions in the host. The aim of this study is to evaluate the effects of L. paracasei ET-22 on the formation of S. mutans biofilms. The living bacteria, heat-killed bacteria, and secretions of L. paracasei ET-22 were prepared using the same number of bacteria. In vitro, they were added into artificial-saliva medium, and used to coculture with the S. mutans. Results showed that the living bacteria and secretions of L. paracasei ET-22 inhibited biofilm-growth, the synthesis of water-soluble polysaccharide and water-insoluble polysaccharide, and virulence-gene-expression levels related to the formation of S. mutans biofilms. Surprisingly, the heat-killed L. paracasei ET-22, which is a postbiotic, also showed a similar regulation function. Non-targeted metabonomics technology was used to identify multiple potential active-substances in the postbiotics of L. paracasei ET-22 that inhibit the formation of S. mutans biofilms, including phenyllactic acid, zidovudine monophosphate, and citrulline. In conclusion, live bacteria and its postbiotics of L. paracasei ET-22 all have inhibitory effects on the formation of S. mutans biofilm. The postbiotics of L. paracasei ET-22 may be a promising biological anticariogenic-agent.

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.

Heat-killed probiotic Lactobacillus plantarum affects the function of neutrophils but does not improve survival in murine burn injury

Probiotics have become of interest as therapeutics in trauma or sepsis-induced inflammation due to their ability to affects the immune response. However, their use is still under debate due to the potential risk of septicemia. Therefore, heat-killed probiotics offer a potential alternative, with recent research suggesting a comparable immunomodulating potential and increased safety. In a previous study, we demonstrated decreased mortality by administration of live Lactobacillus plantarum in a mouse burn-sepsis model. Neutrophils are an essential innate defense against pathogens. Therefore, our present study aims to understand the impact of heat-killed probiotic L. plantarum (HKLP) on neutrophil function. Utilizing an in vitro stimulation with HKLP and a burn-infection in vivo model, we determined that administration of HKLP induced significant release of granulocyte-colony stimulating factor (G-CSF) and stimulated the release of pro-and anti-inflammatory cytokines. HKLP had no impact on neutrophil function, such as phagocytosis, oxidative burst, and NETosis, but increased apoptosis and activated neutrophils. HKLP did not improve survival. Together, contrary to our hypothesis, heat-killed probiotics did not improve neutrophil function and survival outcome in a murine severe burn injury model.

Associations between self-reported psychological symptom severity and gut microbiota: further support for the microgenderome

BACKGROUND

Research into the brain-gut-microbiota axis (BGMA) continues to reveal associations between gut microbiota (GM) and psychological symptom expression, inspiring new ways of conceptualising psychological disorders. However, before GM modulation can be touted as a possible auxiliary treatment option, more research is needed as inconsistencies in previous findings regarding these associations are prevalent. Additionally, the concept of the microgenderome, which proposes that GM may interact with sex hormones, has received limited attention in studies using human samples to date. However, such research has demonstrated sex specific associations between GM and psychological symptom expression.

METHOD

This cross-sectional retrospective study explores associations between GM species (identified through faecal microbial analysis) and symptom severity across four psychological domains (Depressive, Neurocognitive, Stress and Anxiety, and Sleep and Fatigue) for males (N = 1143) and females (N = 3467) separately.

RESULTS

GM species from several genera including Bifidobacterium, Clostridium, Enterococcus, and Leuconostoc were found to be differentially associated with psychological symptom severity for males and females. As such, the findings of the current study provide support for the concept of the microgenderome.

CONCLUSION

While further research is needed before their implementation in psychological treatment plans, the current findings suggest that modulation of GM at the species level may hold promise as auxiliary diagnostic or treatment options. These findings may give further insight into a client's presenting problem from a more holistic, multidisciplinary perspective. The clear sex divergence in associations between GM and symptoms give insight into sex discrepancies in susceptibility to psychological disorders.

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.

Health-Promoting Properties of Lacticaseibacillus paracasei: A Focus on Kefir Isolates and Exopolysaccharide-Producing Strains

Among artisanal fermented beverages, kefir (fermented milk drink) and water kefir (fermented nondairy beverage) are of special interest because their grains can be considered natural reservoirs of safe and potentially probiotic strains. In the last years, several reports on Lacticaseibacillus paracasei (formerly Lactobacillus paracasei) isolated from both artisanal fermented beverages were published focusing on their health-promoting properties. Although this is not the predominant species in kefir or water kefir, it may contribute to the health benefits associated to the consumption of the fermented beverage. Since the classification of L. paracasei has been a difficult task, the selection of an adequate method for identification, which is essential to avoid mislabeling in products, publications, and some publicly available DNA sequences, is discussed in the present work. The last findings in health promoting properties of L. paracasei and the bioactive compounds are described and compared to strains isolated from kefir, providing a special focus on exopolysaccharides as effector molecules. The knowledge of the state of the art of Lacticaseibacillus paracasei from kefir and water kefir can help to understand the contribution of these microorganisms to the health benefits of artisanal beverages as well as to discover new probiotic strains for applications in food industry.