Effect of dietary heat-killed Lactobacillus brevis SBC8803 (SBL88™) on sleep: a non-randomised, double blind, placebo-controlled, and crossover pilot study

Levilactobacillus brevis SG031 modulates mood-related behaviors and attenuates stress-related sleep disturbance and autonomic dysfunction via gut microbiota modulation in Wistar-Kyoto rats

AIMS

The probiotic bacterium Levilactobacillus brevis (L. brevis) has been proposed as a potential solution to manage mood disorders and alleviate stress-related sleep disturbances. However, the underlying mechanisms of its effects have not been fully elucidated. The aim of this study was to explore the impact and potential mechanisms of L. brevis SG031 supplementation on anxiety/depression-like behaviors and stress-induced changes in sleep patterns and sleep-related autonomic function.

MAIN METHODS

Male Wistar-Kyoto rats were administered low, medium, or high doses of L. brevis SG031 or a vehicle for 4 weeks, followed by behavioral tests to evaluate anxiety and depression. After an additional 2 weeks of SG031 or vehicle administration, a cage-exchange paradigm was performed with 24-hour physiological signal measurements under different stress conditions. Fecal samples were collected to construct a 16S rRNA library and assess fecal short-chain fatty acids (SCFAs).

KEY FINDINGS

High-dose SG031 administration yielded reduced depression-like responses and enhanced social interaction in behavioral tests. It also exhibited a protective effect against stress-induced sleep disturbance characterized by decreased sleep time, increased awake time, and autonomic dysfunction during sleep. Fecal examination indicated that high-dose SG031 administration exerted beneficial effects on gut health by maintaining the gut microbial abundance, preserving stability of the microbial composition, and enriching the gut with SCFAs, which were associated with improvements in sleep and autonomic function.

SIGNIFICANCE

These findings collectively underscore the multifaceted potential of SG031 in addressing mental health and stress-related sleep challenges through the modulation of the gut microbiota.

Microbiota Composition and Probiotics Supplementations on Sleep Quality-A Systematic Review and Meta-Analysis

The gut microbiota (GM) plays a crucial role in human health. The bidirectional interaction between GM and the central nervous system may occur via the microbiota-gut-brain axis, possibly regulating the sleep/wake cycle. Recent reports highlight associations between intestinal dysbiosis and sleep disorders, suggesting that probiotics could ameliorate this condition. However, data are poor and inconsistent. The aim of this quantitative metanalytic study is to assess the GM composition in sleep disturbances and evaluate probiotics' effectiveness for managing sleep disorders. A systematic review was carried out until July 2022 in online databases, limiting the literature research to human studies and English language articles. No significant GM diversity between patients with sleep disturbances versus healthy controls was found, revealed by α-diversity, while β-diversity is missing due to lack of proper reporting. However, probiotics supplementation significantly reduced the self-assessed parameter of sleep quality and disturbances Pittsburgh Sleep Quality Index (PSQI) score compared with the placebo. No difference in the Epworth Sleepiness Scale (ESS) score was found. While available data suggest that GM diversity is not related to sleep disturbances, probiotics administration strongly improves sleep quality as a subjective perception. However, heterogeneity of data reporting in the scientific literature should be considered as a limitation.

Probiotics, prebiotics and postbiotics for better sleep quality: a narrative review

There is a growing prevalence of sleep problems and insomnia worldwide, urging the development of new treatments to tackle this increase. Several studies have suggested that the gut microbiome might influence sleep quality. The gut microbiome affects the host's health via the production of metabolites and compounds with neuroactive and immunomodulatory properties, which include short-chain fatty acids, secondary bile acids and neurotransmitters. Several of these metabolites and compounds are independently known as wakefulness-promoting (serotonin, epinephrine, dopamine, orexin, histamine, acetylcholine, cortisol) or sleep-promoting (gamma-aminobutyric acid, melatonin). The primary aim of this review was to evaluate the potential of pro-, pre- and postbiotic treatments to improve sleep quality. Additionally, we aimed to evaluate whether each of the treatments could ameliorate stress and anxiety, which are known to bidirectionally correlate with sleep problems. Lastly, we provided a mechanistic explanation for our findings. A literature search was conducted using PubMed, Scopus, Web of Science, and Google Scholar to compare all human trials that met our inclusion criteria and were published before November 2021. We furthermore discussed relevant findings from animal experiments to provide a mechanistic insight. While several studies found that sleep latency, sleep length, and cortisol levels improved after pro-, pre- or postbiotic treatment, others did not show any significant improvements for sleep quality, stress, or anxiety. These discrepancies can be explained by between-study variations in study designs, study populations, treatments, type and level of distress, and sex differences. We conclude that the trials discussed provide some evidence for prebiotics, postbiotics, and traditional probiotics, such as those belonging to lactobacilli and bifidobacteria, to improve sleep quality and stress, but stronger evidence might be found in the future after implementing the methodological adjustments that are suggested in this review.

The Component and Functional Pathways of Gut Microbiota Are Altered in Populations with Poor Sleep Quality - A Preliminary Report

With the development of genome sequencing, many researchers have investigated the mechanism by which the intestinal microbiota influences sleep across the brain-gut axis. However, the relationship between gut microbiota and sleep disorder remains unclear. Thus, we studied the difference in gut microbiota composition between poor sleep quality- and normal populations, which helps set the ground for future research. The recruited college students provided baseline information and stool samples and completed the Pittsburgh Sleep Quality Index (PSQI). We compared the two groups’ gut microbiota composition and functional differentiation by using the 16S rRNA gene sequencing analysis. The main bacterial difference and the most critical effect were mainly concentrated within Tenericutes and Elusimicrobia. Compared with the healthy control group, some functions of the gut microbiota were impaired in the poor sleep quality group, such as butanoate metabolism and propanoate metabolism. Bacterial taxa with significant differences raised the possibility for future diagnosis and treatment of sleep problems.

Production of Lactobacillus brevis ProGA28 attenuates stress-related sleep disturbance and modulates the autonomic nervous system and the motor response in anxiety/depression behavioral tests in Wistar-Kyoto rats

AIMS

Many studies have reported that the production of Lactobacillus brevis is beneficial for sleep, but the underlying mechanism remains unclear. Other known beneficial effects of Lactobacillus brevis include improvement of anxious or depressive symptoms and better modulation of the autonomic nervous system, both of which impact sleep. In this study, we investigated whether the sleep benefit of Lactobacillus brevis was associated with the modulating effects on the autonomic nervous system and anxious/depressive symptoms.

MAIN METHODS

Wistar-Kyoto rats were fed the production of Lactobacillus brevis (ProGA28) for the last 2 weeks of treatment before being exposed to case exchange (stress-induced insomnia paradigm). Waking, quiet sleep, and paradoxical sleep states were defined based on polysomnographic measurements. Autonomic functioning was assessed by heart rate variability (HRV). A combined behavioral test was used to evaluate anxiety-like or depressive-like behaviors after the following 2 days.

KEY FINDINGS

In exposure to the dirty cage, the control group had significant prolongation of sleep latency, sleep loss during the first 2 h, and decreased parasympathetic activity and increased sympathetic activity during quiet sleep, which were significantly mitigated in the ProGA28 group. In behavioral tests, the ProGA28 group exhibited significantly less anxiety/depression-like motor responses in the elevated plus maze test, the forced swimming test, and the three-chamber social interaction test. Less initial sleep loss in the ProGA28 group was related to higher parasympathetic activity during quiet sleep, and shorter sleep latency in both groups was associated with longer time staying in the open arm in the elevated plus maze test.

SIGNIFICANCE

These findings suggest that L. brevis ProGA28 can attenuate stress-related sleep disturbance, which may be associated with increased parasympathetic activity and decreased anxiety-like behaviors.

Microbiome therapeutics: exploring the present scenario and challenges

Human gut-microbiome explorations have enriched our understanding of microbial colonization, maturation, and dysbiosis in health-and-disease subsets. The enormous metabolic potential of gut microbes and their role in the maintenance of human health is emerging, with new avenues to use them as therapeutic agents to overcome human disorders. Microbiome therapeutics are aimed at engineering the gut microbiome using additive, subtractive, or modulatory therapy with an application of native or engineered microbes, antibiotics, bacteriophages, and bacteriocins. This approach could overcome the limitation of conventional therapeutics by providing personalized, harmonized, reliable, and sustainable treatment. Its huge economic potential has been shown in the global therapeutics market. Despite the therapeutic and economical potential, microbiome therapeutics is still in the developing stage and is facing various technical and administrative issues that require research attention. This review aims to address the current knowledge and landscape of microbiome therapeutics, provides an overview of existing health-and-disease applications, and discusses the potential future directions of microbiome modulations.

Effect of Lacticaseibacillus paracasei Strain Shirota on Improvement in Depressive Symptoms, and Its Association with Abundance of Actinobacteria in Gut Microbiota

We previously reported lower counts of lactobacilli and Bifidobacterium in the gut microbiota of patients with major depressive disorder (MDD), compared with healthy controls. This prompted us to investigate the possible efficacy of a probiotic strain, Lacticaseibacillus paracasei strain Shirota (LcS; basonym, Lactobacillus casei strain Shirota; daily intake of 8.0 × 10¹⁰ colony-forming units), in alleviating depressive symptoms. A single-arm trial was conducted on 18 eligible patients with MDD or bipolar disorder (BD) (14 females and 4 males; 15 MDD and 3 BD), assessing changes in psychiatric symptoms, the gut microbiota, and biological markers for intestinal permeability and inflammation, over a 12-week intervention period. Depression severity, evaluated by the Hamilton Depression Rating Scale, was significantly alleviated after LcS treatment. The intervention-associated reduction of depressive symptoms was associated with the gut microbiota, and more pronounced when Bifidobacterium and the Atopobium clusters of the Actinobacteria phylum were maintained at higher counts. No significant changes were observed in the intestinal permeability or inflammation markers. Although it was difficult to estimate the extent of the effect of LcS treatment alone, the results indicated that it was beneficial to alleviate depressive symptoms, partly through its association with abundance of Actinobacteria in the gut microbiota.

Probiotics: A Dietary Factor to Modulate the Gut Microbiome, Host Immune System, and Gut-Brain Interaction

Various benefits of probiotics to the host have been shown in numerous human clinical trials. These organisms have been proposed to act by improving the balance of the gut microbiota and enhancing the production of short-chain fatty acids, as well as by interacting with host cells in the gastrointestinal tract, including immune cells, nerve cells, and endocrine cells. Although the stimulation of host cells by probiotics and subsequent signaling have been explained by in vitro experiments and animal studies, there has been some skepticism as to whether probiotics can actually interact with host cells in the human gastrointestinal tract, where miscellaneous indigenous bacteria coexist. Most recently, it has been shown that the ileal microbiota in humans after consumption of a fermented milk is occupied by probiotics for several hours, indicating that there is adequate opportunity for the ingested strain to stimulate the host cells continuously over a period of time. As the dynamics of ingested probiotics in the human gastrointestinal tract become clearer, further progress in this research area is expected to elucidate their behavior within the tract, as well as the mechanism of their physiological effects on the host.

Effects of probiotics and paraprobiotics on subjective and objective sleep metrics: a systematic review and meta-analysis

Inadequate sleep (i.e., duration and/or quality) is becoming increasingly recognized as a global public health issue. Interaction via the gut-brain axis suggests that modification of the gut microbial environment via supplementation with live microorganisms (probiotics) or nonviable microorganisms/microbial cell fractions (paraprobiotics) may improve sleep health. This systematic review and meta-analysis aimed to clarify the effect of consuming probiotics/paraprobiotics on subjective and objective sleep metrics. Online databases were searched from 1980 to October 2019 for studies involving adults who consumed probiotics or paraprobiotics in controlled trials, during which, changes in subjective and/or objective sleep parameters were examined. A total of 14 studies (20 trials) were included in meta-analysis. Random effects meta-analyses indicated that probiotics/paraprobiotics supplementation significantly reduced Pittsburgh Sleep Quality Index (PSQI) score (i.e., improved sleep quality) relative to baseline (-0.78-points, 95% confidence interval: 0.395-1.166; p < 0.001). No significant effect was found for changes on other subjective sleep scales, nor objective parameters of sleep (efficiency/latency) measured using polysomnography or actigraphy. Subgroup analysis for PSQI data suggested that the magnitude of the effect was greater (although not statistically) in healthy participants than those with a medical condition, when treatment contained a single (rather than multiple) strain of probiotic bacteria, and when the duration of treatment was ≥8 weeks. Probiotics/paraprobiotics supplementation may have some efficacy in improving perceived sleep health, measured using the PSQI. While current evidence does not support a benefit of consuming probiotics/paraprobiotics when measured by other subjective sleep scales, nor objective measures of sleep; more studies using well-controlled, within-subject experimental designs are needed.

Delivery to the gut microbiota: A rapidly proliferating research field

The post genomic era has brought breakthroughs in our understanding of the complex and fascinating symbiosis we have with our co-evolving microbiota, and its dramatic impact on our physiology, physical and mental health, mood, interpersonal communication, and more. This fast "proliferating" knowledge, particularly related to the gut microbiota, is leading to the development of numerous technologies aimed to promote our health via prudent modulation of our gut microbiota. This review embarks on a journey through the gastrointestinal tract from a biomaterial science and engineering perspective, and focusses on the various state-of-the-art approaches proposed in research institutes and those already used in various industries and clinics, for delivery to the gut microbiota, with emphasis on the latest developments published within the last 5 years. Current and possible future trends are discussed. It seems that future development will progress toward more personalized solutions, combining high throughput diagnostic omic methods, and precision interventions.

Oral administration of heat-killed Lactobacillus brevis SBC8803 elevates the ratio of acyl/des-acyl ghrelin in blood and increases short-term food intake

It is known that gastrointestinal microbiota, probiotics and heat-killed microbes can regulate intestinal immunity; however, their effect on the secretion of gastrointestinal hormones is unclear. The secretion of gastrointestinal hormones can be mediated by the elevation of intracellular Ca2+ concentration, suggesting that these hormones may act through common mechanisms. We have previously shown that heat-killed Lactobacillus brevis SBC8803 (hk-SBC8803) induced the secretion of serotonin and elevated intracellular Ca2+ concentration in serotonin-producing RIN-14B cells, suggesting that hk-SBC8803 could potentially cause the same effect on other gastrointestinal hormones, including hunger hormone ghrelin. Here, we tested this hypothesis by treating cultured cells and experimental animals with hk-SBC8803 and assessing ghrelin secretion, expression of ghrelin-related genes, and food intake. The results indicated that hk-SBC8803 treatment for 30 min significantly upregulated the secretion of acyl ghrelin (active form) (P=0.046) and mRNA expression of the Syt3 (synaptotagmin 3) gene related to ghrelin exocytosis (P<0.05) in primary mouse stomach cells. In addition, oral administration of 500 mg/kg hk-SBC8803 to rats tended to upregulate acyl ghrelin concentration (P=0.10) and significantly increased the ratio of acyl to des-acyl (inactive) ghrelin (P=0.027) in blood, which corresponded to a tendency of stimulating food intake (P=0.087) at 30 min post-treatment. However, when in order to minimise individual differences we normalised the data on food intake to those on one-day food intake prior to food deprivation, the resultant food intake ratio showed a significant increase (by 5% compared to control; P=0.032) at 30 min after hk-SBC8803 treatment, indicating that hk-SBC8803 administration stimulated rats to take more food during the first meal after fasting. These results suggest that hk-SBC8803 induces short-term ghrelin secretion and transiently increases appetite, which is an important effect for individuals with low energy intake.

Psychobiotics in mental health, neurodegenerative and neurodevelopmental disorders

Psychobiotics are a group of probiotics that affect the central nervous system (CNS) related functions and behaviors mediated by the gut-brain-axis (GBA) via immune, humoral, neural, and metabolic pathways to improve not only the gastrointestinal (GI) function but also the antidepressant and anxiolytic capacity. As a novel class of probiotics, the application of psychobiotics has led researchers to focus on a new area in neuroscience. In the past five years, some psychobiotics strains were reported to inhibit inflammation and decreased cortisol levels, resulting in an amelioration of the symptoms of anxiety and depression. Psychobiotics are efficacious in improving neurodegenerative and neurodevelopmental disorders, including autism spectrum disorder (ASD), Parkinson’s disease (PD) and Alzheimer’s disease (AD). Use of psychobiotics can improve GI function, ASD symptoms, motor functions of patients with PD and cognition in patients with AD. However, the evidence for the effects of psychobiotics on mental and neurological conditions/ disorders remains limited. Further studies of psychobiotics are needed in order to determine into their effectiveness and mechanism as treatments for various psychiatric disorders in the future.

Dietary heat-killed Lactobacillus brevis SBC8803 (SBL88™) improves hippocampus-dependent memory performance and adult hippocampal neurogenesis

Aims

Lactobacillus species are used widely as various food and supplements to improve health. Previous studies have shown that heat‐killed Lactobacillus brevis SBC8803 induces serotonin release from intestinal cells and affects sleep rhythm and the autonomic nervous system. However, the effect of SBC8803 on cognitive function remains unknown. Here, we examined the effects of dietary heat‐killed SBC8803 on hippocampus‐dependent memory and adult hippocampal neurogenesis.

Methods

Hippocampus‐dependent memory performance was assessed in mice fed heat‐killed SBC8803 using social recognition and contextual fear conditioning tasks. Adult hippocampal neurogenesis was evaluated before, during, and after feeding heat‐killed SBC8803 by measuring the number of 5‐bromo‐2‐deoxyuridine (BrdU)‐positive cells following systemic injections of BrdU using immunohistochemistry.

Results

Mice fed a heat‐killed SBC8803 diet showed an improvement of hippocampus‐dependent social recognition and contextual fear memories and enhanced adult hippocampal neurogenesis by increasing the survival, but not proliferation, of newborn neurons.

Conclusion

Dietary heat‐killed SBC8803 functions as memory and neurogenesis enhancers.

Mice fed a heat‐killed Lactobacillus brevis SBC8803 diet showed an improvement of hippocampus‐dependent social recognition and contextual fear memories and enhanced adult hippocampal neurogenesis by increasing the survival of newborn neurons.

Probiotics in Extraintestinal Diseases: Current Trends and New Directions

Probiotics are defined as live microorganisms that when administered in adequate amounts confer a health benefit to the host. Their positive supplementation outcomes on several gastrointestinal disorders are well defined. Nevertheless, their actions are not limited to the gut, but may also impart their beneficial effects at distant sites and organs. In this regard, in this review article we: (i) comprehensively describe the main mechanisms of action of probiotics at distant sites, including bones, skin, and brain; (ii) critically present their therapeutic potential against bone, skin, and neuronal diseases (e.g., osteoporosis, non-healing wounds and autoimmune skin illnesses, mood, behavior, memory, and cognitive impairments); (iii) address the current gaps in the preclinical and clinical research; and (iv) indicate new research directions and suggest future investigations.

Dysbiotic drift and biopsychosocial medicine: how the microbiome links personal, public and planetary health

The emerging concept of planetary health emphasizes that the health of human civilization is intricately connected to the health of natural systems within the Earth’s biosphere; here, we focus on the rapidly progressing microbiome science - the microbiota-mental health research in particular - as a way to illustrate the pathways by which exposure to biodiversity supports health. Microbiome science is illuminating the ways in which stress, socioeconomic disadvantage and social polices interact with lifestyle and behaviour to influence the micro and macro-level biodiversity that otherwise mediates health. Although the unfolding microbiome and mental health research is dominated by optimism in biomedical solutions (e.g. probiotics, prebiotics), we focus on the upstream psychosocial and ecological factors implicated in dysbiosis; we connect grand scale biodiversity in the external environment with differences in human-associated microbiota, and, by extension, differences in immune function and mental outlook. We argue that the success of planetary health as a new concept will be strengthened by a more sophisticated understanding of the ways in which individuals develop emotional connections to nature (nature relatedness) and the social policies and practices which facilitate or inhibit the pro-environmental values that otherwise support personal, public and planetary health.

Word-of-Mouth Innovation: Hypothesis Generation for Supplement Repurposing based on Consumer Reviews

Dietary supplements remain a relatively underexplored source for drug repurposing. A systematic approach to soliciting responses from a large consumer population is desirable to speed up innovation. We tested a workflow that mines unexpected benefits of dietary supplements from massive consumer reviews. A (non-exhaustive) list of regular expressions was used to screen over 2 million reviews on health and personal care products. The matched reviews were manually analyzed, and one supplement-disease pair was linked to biological databases for enriching the hypothesized association. The regular expressions found 169 candidate reviews, of which 45.6% described unexpected benefits of certain dietary supplements. The manual analysis showed some of the supplement-disease associations to be novel or in agreement with evidence published later in the literature. The hypothesis enrichment was able to identify meaningful function similarity between the supplement and the disease. The results demonstrated value of the workflow in identifying candidates for supplement repurposing.

Dietary Prebiotics and Bioactive Milk Fractions Improve NREM Sleep, Enhance REM Sleep Rebound and Attenuate the Stress-Induced Decrease in Diurnal Temperature and Gut Microbial Alpha Diversity

Severe, repeated or chronic stress produces negative health outcomes including disruptions of the sleep/wake cycle and gut microbial dysbiosis. Diets rich in prebiotics and glycoproteins impact the gut microbiota and may increase gut microbial species that reduce the impact of stress. This experiment tested the hypothesis that consumption of dietary prebiotics, lactoferrin (Lf) and milk fat globule membrane (MFGM) will reduce the negative physiological impacts of stress. Male F344 rats, postnatal day (PND) 24, received a diet with prebiotics, Lf and MFGM (test) or a calorically matched control diet. Fecal samples were collected on PND 35/70/91 for 16S rRNA sequencing to examine microbial composition and, in a subset of rats; Lactobacillus rhamnosus was measured using selective culture. On PND 59, biotelemetry devices were implanted to record sleep/wake electroencephalographic (EEG). Rats were exposed to an acute stressor (100, 1.5 mA, tail shocks) on PND 87 and recordings continued until PND 94. Test diet, compared to control diet, increased fecal Lactobacillus rhamnosus colony forming units (CFU), facilitated non-rapid eye movement (NREM) sleep consolidation (PND 71/72) and enhanced rapid eye movement (REM) sleep rebound after stressor exposure (PND 87). Rats fed control diet had stress-induced reductions in alpha diversity and diurnal amplitude of temperature, which were attenuated by the test diet (PND 91). Stepwise multiple regression analysis revealed a significant linear relationship between early-life Deferribacteres (PND 35) and longer NREM sleep episodes (PND 71/72). A diet containing prebiotics, Lf and MFGM enhanced sleep quality, which was related to changes in gut bacteria and modulated the impact of stress on sleep, diurnal rhythms and the gut microbiota.