Potential Modulation of Inflammation and Physical Function by Combined Probiotics, Omega-3 Supplementation and Vitamin D Supplementation in Overweight/Obese Patients with Chronic Low-Grade Inflammation: A Randomized, Placebo-Controlled Trial

Obesity is characterized by low-grade inflammation and increased gut permeability. Here, we aim to evaluate the effect of a nutritional supplement on these parameters in subjects with overweight and obesity. A double-blinded, randomized clinical trial was conducted in 76 adults with overweight or obesity (BMI 28 to 40) and low-grade inflammation (high-sensitivity C-reactive protein (hs-CRP) between 2 and 10 mg/L). The intervention consisted of a daily intake of a multi-strain probiotic of Lactobacillus and Bifidobacterium, 640 mg of omega-3 fatty acids (n-3 FAs), and 200 IU of vitamin D (n = 37) or placebo (n = 39), administered for 8 weeks. hs-CRP levels did not change post-intervention, other than an unexpected slight increase observed in the treatment group. Interleukin (IL)-6 levels decreased in the treatment group (p = 0.018). The plasma fatty acid (FA) levels of the arachidonic acid (AA)/eicosapentaenoic acid (EPA) ratio and n-6/n-3 ratio (p < 0.001) decreased, and physical function and mobility improved in the treatment group (p = 0.006). The results suggest that hs-CRP may not be the most useful inflammatory marker, but probiotics, n-3 FAs, and vitamin D, as non-pharmaceutical supplements, may exert modest effects on inflammation, plasma FA levels, and physical function in patients with overweight and obesity and associated low-grade inflammation.

Potential Modulation of Inflammation by Probiotic and Omega-3 Supplementation in Elderly with Chronic Low-Grade Inflammation—A Randomized, Placebo-Controlled Trial

Probiotic and omega-3 supplements have been shown to reduce inflammation, and dual supplementation may have synergistic health effects. We investigated if the novel combination of a multi-strain probiotic (containing B. lactis Bi-07, L. paracasei Lpc-37, L. acidophilus NCFM, and B. lactis Bl-04) alongside omega-3 supplements reduces low-grade inflammation as measured by high-sensitivity C-reactive protein (hs-CRP) in elderly participants in a proof-of-concept, randomized, placebo-controlled, parallel study (NCT04126330). In this case, 76 community-dwelling elderly participants (median: 71.0 years; IQR: 68.0–73.8) underwent an intervention with the dual supplement (n = 37) or placebo (n = 39) for eight weeks. In addition to hs-CRP, cytokine levels and intestinal permeability were also assessed at baseline and after the eight-week intervention. No significant difference was seen for hs-CRP between the dual supplement group and placebo. However, interestingly, supplementation did result in significant increases in the level of the anti-inflammatory marker IL-10. In addition, dual supplementation increased levels of valeric acid, further suggesting the potential of the supplements in reducing inflammation and conferring health benefits. Together, the results suggest that probiotic and omega-3 dual supplementation exerts modest effects on inflammation and may have potential use as a non-pharmacological treatment for low-grade inflammation in the elderly.

Multi-Strain Probiotic Mixture Affects Brain Morphology and Resting State Brain Function in Healthy Subjects: An RCT

Probiotics can alter brain function via the gut–brain axis. We investigated the effect of a probiotic mixture containing Bifidobacterium longum, Lactobacillus helveticus and Lactiplantibacillus plantarum. In a randomized, placebo-controlled, double-blinded crossover design, 22 healthy subjects (6 m/16 f; 24.2 ± 3.4 years) underwent four-week intervention periods with probiotics and placebo, separated by a four-week washout period. Voxel-based morphometry indicated that the probiotic intervention affected the gray matter volume of a cluster covering the left supramarginal gyrus and superior parietal lobule (p < 0.0001), two regions that were also among those with an altered resting state functional connectivity. Probiotic intervention resulted in significant (FDR < 0.05) functional connectivity changes between regions within the default mode, salience, frontoparietal as well as the language network and several regions located outside these networks. Psychological symptoms trended towards improvement after probiotic intervention, i.e., the total score of the Hospital Anxiety and Depression Scale (p = 0.056) and its depression sub-score (p = 0.093), as well as sleep patterns (p = 0.058). The probiotic intervention evoked distinct changes in brain morphology and resting state brain function alongside slight improvements of psycho(bio)logical markers of the gut–brain axis. The combination of those parameters may provide new insights into the modes of action by which gut microbiota can affect gut–brain communication and hence brain function.

Probiotic Mixture Containing Lactobacillus helveticus, Bifidobacterium longum and Lactiplantibacillus plantarum Affects Brain Responses Toward an Emotional Task in Healthy Subjects: A Randomized Clinical Trial

Background

Evidence from preclinical studies suggests that probiotics affect brain function via the microbiome-gut-brain axis, but evidence in humans remains limited.

Objective

The present proof-of-concept study investigated if a probiotic product containing a mixture of Bifidobacterium longum R0175, Lactobacillus helveticus R0052 and Lactiplantibacillus plantarum R1012 (in total 3 × 10⁹ CFU/day) affected functional brain responses in healthy subjects during an emotional attention task.

Design

In this double-blinded, randomized, placebo-controlled crossover study (Clinicaltrials.gov, NCT03615651), 22 healthy subjects (24.2 ± 3.4 years, 6 males/16 females) were exposed to a probiotic intervention and a placebo for 4 weeks each, separated by a 4-week washout period. Subjects underwent functional magnetic resonance imaging while performing an emotional attention task after each intervention period. Differential brain activity and functional connectivity were assessed.

Results

Altered brain responses were observed in brain regions implicated in emotional, cognitive and face processing. Increased activation in the orbitofrontal cortex, a region that receives extensive sensory input and in turn projects to regions implicated in emotional processing, was found after probiotic intervention compared to placebo using a cluster-based analysis of functionally defined areas. Significantly reduced task-related functional connectivity was observed after the probiotic intervention compared to placebo. Fecal microbiota composition was not majorly affected by probiotic intervention.

Conclusion

The probiotic intervention resulted in subtly altered brain activity and functional connectivity in healthy subjects performing an emotional task without major effects on the fecal microbiota composition. This indicates that the probiotic effects occurred via microbe-host interactions on other levels. Further analysis of signaling molecules could give possible insights into the modes of action of the probiotic intervention on the gut-brain axis in general and brain function specifically. The presented findings further support the growing consensus that probiotic supplementation influences brain function and emotional regulation, even in healthy subjects. Future studies including patients with altered emotional processing, such as anxiety or depression symptoms are of great interest.

Clinical Trial Registration

[http://clinicaltrials.gov/], identifier [NCT03615651].

Probiotic Mixture Containing Lactobacillus helveticus, Bifidobacterium longum and Lactiplantibacillus plantarum Affects Brain Responses to an Arithmetic Stress Task in Healthy Subjects: A Randomised Clinical Trial and Proof-of-Concept Study

Probiotics are suggested to impact physiological and psychological stress responses by acting on the gut-brain axis. We investigated if a probiotic product containing Bifidobacterium longum R0175, Lactobacillus helveticus R0052 and Lactiplantibacillus plantarum R1012 affected stress processing in a double-blinded, randomised, placebo-controlled, crossover proof-of-concept study (NCT03615651). Twenty-two healthy subjects (24.2 ± 3.4 years, 6 men/16 women) underwent a probiotic and placebo intervention for 4 weeks each, separated by a 4-week washout period. Subjects were examined by functional magnetic resonance imaging while performing the Montreal Imaging Stress Task (MIST) as well as an autonomic nervous system function assessment during the Stroop task. Reduced activation in regions of the lateral orbital and ventral cingulate gyri was observed after probiotic intervention compared to placebo. Significantly increased functional connectivity was found between the upper limbic region and medioventral area. Interestingly, probiotic intervention seemed to predominantly affect the initial stress response. Salivary cortisol secretion during the task was not altered. Probiotic intervention did not affect cognitive performance and autonomic nervous system function during Stroop. The probiotic intervention was able to subtly alter brain activity and functional connectivity in regions known to regulate emotion and stress responses. These findings support the potential of probiotics as a non-pharmaceutical treatment modality for stress-related disorders.

Genome-wide activity-dependent MeCP2 phosphorylation regulates nervous system development and function

Autism spectrum disorders such as Rett syndrome (RTT) have been hypothesized to arise from defects in experience-dependent synapse maturation. RTT is caused by mutations in MECP2, a nuclear protein that becomes phosphorylated at S421 in response to neuronal activation. We show here that disruption of MeCP2 S421 phosphorylation in vivo results in defects in synapse development and behavior, implicating activity-dependent regulation of MeCP2 in brain development and RTT. We investigated the mechanism by which S421 phosphorylation regulates MeCP2 function and show by chromatin immunoprecipitation-sequencing that this modification occurs on MeCP2 bound across the genome. The phosphorylation of MeCP2 S421 appears not to regulate the expression of specific genes; rather, MeCP2 functions as a histone-like factor whose phosphorylation may facilitate a genome-wide response of chromatin to neuronal activity during nervous system development. We propose that RTT results in part from a loss of this experience-dependent chromatin remodeling.

MeCP2 in the nucleus accumbens contributes to neural and behavioral responses to psychostimulants

MeCP2 is a methyl DNA-binding transcriptional regulator that contributes to the development and function of CNS synapses; however, the requirement for MeCP2 in stimulus-regulated behavioral plasticity is not fully understood. Here we show that acute viral manipulation of MeCP2 expression in the nucleus accumbens (NAc) bidirectionally modulates amphetamine (AMPH)-induced conditioned place preference. Mecp2 hypomorphic mutant mice have more NAc GABAergic synapses and show deficient AMPH-induced structural plasticity of NAc dendritic spines. Furthermore, these mice show deficient plasticity of striatal immediate early gene inducibility after repeated AMPH administration. Notably, psychostimulants induce phosphorylation of MeCP2 at Ser421, a site that regulates MeCP2's function as a repressor. Phosphorylation is selectively induced in GABAergic interneurons of the NAc, and its extent strongly predicts the degree of behavioral sensitization. These data reveal new roles for MeCP2 both in mesolimbocortical circuit development and in the regulation of psychostimulant-induced behaviors.

Reduced cortical BDNF expression and aberrant memory in Carf knock-out mice

Transcription factors are a key point of convergence between the cell-intrinsic and extracellular signals that guide synaptic development and brain plasticity. Calcium-response factor (CaRF) is a unique transcription factor first identified as a binding protein for a calcium-response element in the gene encoding brain-derived neurotrophic factor (Bdnf). We have now generated Carf knock-out (KO) mice to characterize the function of this factor in vivo. Intriguingly, Carf KO mice have selectively reduced expression of Bdnf exon IV-containing mRNA transcripts and BDNF protein in the cerebral cortex, whereas BDNF levels in the hippocampus and striatum remain unchanged, implicating CaRF as a brain region-selective regulator of BDNF expression. At the cellular level, Carf KO mice show altered expression of GABAergic proteins at striatal synapses, raising the possibility that CaRF may contribute to aspects of inhibitory synapse development. Carf KO mice show normal spatial learning in the Morris water maze and normal context-dependent fear conditioning. However they have an enhanced ability to find a new platform location on the first day of reversal training in the water maze and they extinguish conditioned fear more slowly than their wild-type littermates. Finally, Carf KO mice show normal short-term (STM) and long-term memory (LTM) in a novel object recognition task, but exhibit impairments during the remote memory phase of testing. Together, these data reveal novel roles for CaRF in the organization and/or function of neural circuits that underlie essential aspects of learning and memory.