Neurotransmitters: The Critical Modulators Regulating Gut-Brain Axis

A first glimpse into the transcriptomic changes induced by the PaV1 infection in the gut of Caribbean spiny lobsters, Panulirus argus (Latreille, 1804) (Decapoda: Achelata: Palinuridae)

The Caribbean spiny lobster, Panulirus argus (Latreille, 1804) supports important fisheries in the Caribbean region. This species is affected by a deadly virus, Panulirus argus Virus 1 (PaV1), the only known pathogenic virus for this species. As infection progresses, the effects of PaV1 on its host become systemic, with far reaching impacts on the host's physiology, including structural injuries to its gastrointestinal organs, such as the hepatopancreas and the gut. This last one becomes highly compromised in the last stages of infection. Since the gut is a key organ for the physiological stability of lobsters, we compared the transcriptomic changes in the gut of juvenile individuals of Panulirus argus naturally infected with PaV1. In the RNA-Seq analysis, we obtained a total of 485 × 10⁶ raw reads. After cleaning, reads were de novo assembled into 68,842 transcripts and 50,257 unigenes. The length of unigenes ranged from 201 bp to 28,717 bp, with a N50 length of 2079, and a GC content of 40.61%. In the differential gene expression analysis, we identified a total of 3,405 non redundant differential transcripts, of which 1,920 were up-regulated and 1,485 were down-regulated. We found alterations in transcripts encoding for proteins involved in transcriptional regulation, splicing, postraductional regulation, protein signaling, transmembrane transport, cytoskeletal regulation, and proteolysis, among others. This is the first insight into the transcriptomic regulation of PaV1-P. argus interaction. The information generated can help to unravel the molecular mechanisms that may intervene in the gut during PaV1 infection.

Molecular Probes, Chemosensors, and Nanosensors for Optical Detection of Biorelevant Molecules and Ions in Aqueous Media and Biofluids

Synthetic molecular probes, chemosensors, and nanosensors used in combination with innovative assay protocols hold great potential for the development of robust, low-cost, and fast-responding sensors that are applicable in biofluids (urine, blood, and saliva). Particularly, the development of sensors for metabolites, neurotransmitters, drugs, and inorganic ions is highly desirable due to a lack of suitable biosensors. In addition, the monitoring and analysis of metabolic and signaling networks in cells and organisms by optical probes and chemosensors is becoming increasingly important in molecular biology and medicine. Thus, new perspectives for personalized diagnostics, theranostics, and biochemical/medical research will be unlocked when standing limitations of artificial binders and receptors are overcome. In this review, we survey synthetic sensing systems that have promising (future) application potential for the detection of small molecules, cations, and anions in aqueous media and biofluids. Special attention was given to sensing systems that provide a readily measurable optical signal through dynamic covalent chemistry, supramolecular host-guest interactions, or nanoparticles featuring plasmonic effects. This review shall also enable the reader to evaluate the current performance of molecular probes, chemosensors, and nanosensors in terms of sensitivity and selectivity with respect to practical requirement, and thereby inspiring new ideas for the development of further advanced systems.

Potential role of gut microbiota in patients with COVID-19, its relationship with lung axis, central nervous system (CNS) axis, and improvement with probiotic therapy

Coronavirus Disease 2019 (COVID-19) is a pandemic disease caused by a new corona virus. COVID-19 affects different people in different ways. COVID-19 could affect the gastrointestinal system via gut microbiota impairment. Gut microbiota could affect lung health through a relationship between gut and lung microbiota, which is named gut-lung axis. Gut microbiota impairment plays a role in pathogenesis of various pulmonary disease states, so GI diseases were found to be associated with respiratory diseases. Moreover, most infected people will develop mild to moderate gastrointestinal (GI) symptoms such as diarrhea, vomiting, and stomachache, which is caused by impairment in gut microbiota. Therefore, the current study aimed to review potential role of gut microbiota in patients with COVID-19, its relation with lung axis, Central Nervous System (CNS) axis and improvement with probiotic therapy. Also, this review can be a guide for potential role of gut microbiota in patients with COVID-19.

Human Umbilical Cord Mesenchymal Stem Cells Improve Locomotor Function in Parkinson’s Disease Mouse Model Through Regulating Intestinal Microorganisms

Parkinson’s disease (PD) is a progressive neurological disorder characterized by loss of neurons that synthesize dopamine, and subsequent impaired movement. Umbilical cord mesenchymal stem cells (UC-MSCs) exerted neuroprotection effects in a rodent model of PD. However, the mechanism underlying UC-MSC-generated neuroprotection was not fully elucidated. In the present study, we found that intranasal administration of UC-MSCs significantly alleviated locomotor deficits and rescued dopaminergic neurons by inhibiting neuroinflammation in a PD mouse model induced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP, a toxic agent which selectively destroys nigrostriatal neurons but does not affect dopaminergic neurons elsewhere). Furthermore, UC-MSC treatment altered gut microbiota composition characterized by decreased phylum Proteobacteria, class Gammaproteobacteria, family Enterobacteriaceae, and genus Escherichia-Shigella. In addition, the neurotransmitter dopamine in the striatum and 5-hydroxytryptamine in the colon were also modulated by UC-MSCs. Meanwhile, UC-MSCs significantly maintained intestinal goblet cells, which secrete mucus as a mechanical barrier against pathogens. Furthermore, UC-MSCs alleviate the level of TNF-α and IL-6 as well as the conversion of NF-κB expression in the colon, indicating that inflammatory responses were blocked by UC-MSCs. PICRUSt showed that some pathways including bacterial invasion of epithelial cells, fluorobenzoate degradation, and pathogenic Escherichia coli infection were significantly reversed by UC-MSCs. These data suggest that the beneficial effects were detected following UC-MSC intranasal transplantation in MPTP-treated mice. There is a possible neuroprotective role of UC-MSCs in MPTP-induced PD mice by cross talk between the brain and gut.

Neurotransmitter and Intestinal Interactions: Focus on the Microbiota-Gut-Brain Axis in Irritable Bowel Syndrome

Irritable bowel syndrome (IBS) is a functional gastrointestinal disorder of unknown etiology. IBS is caused by a disruption in the gut-brain axis. Given the importance of the gut microbiota in maintaining local and systemic homeostasis of immunity, endocrine, and other physiological processes, the microbiota-gut-brain axis has been proposed as a key regulator in IBS. Neurotransmitters have been shown to affect blood flow regulation, intestinal motility, nutrient absorption, the gastrointestinal immune system, and the microbiota in recent studies. It has the potential role to play a function in the pathophysiology of the gastrointestinal and neurological systems. Transmitters and their receptors, including 5-hydroxytryptamine, dopamine, γ-aminobutyric acid, and histamine, play an important role in IBS, especially in visceral sensitivity and gastrointestinal motility. Studies in this field have shed light on revealing the mechanism by which neurotransmitters act in the pathogenesis of IBS and discovering new therapeutic strategies based on traditional pharmacological approaches that target the nervous system or novel therapies that target the microbiota.

Predictors of Gastrointestinal Transit Times in Colon Capsule Endoscopy

INTRODUCTION

Optimizing the accuracy of colon capsule endoscopy (CCE) requires high completion rates. To prevent incomplete CCE, we aimed to identify predictors associated with slow CCE transit times.

METHODS

In this population-based study, participants received CCE with a split-dose polyethylene glycol bowel preparation and booster regimen (0.5 L oral sulfate solution and 10 mg metoclopramide if capsule remained in stomach for > 1 hour). The following predictors were assessed: age, sex, body mass index (BMI), smoking, coffee and fiber intake, diet quality, physical activity, dyspeptic complaints, stool pattern, history of abdominal surgery, medication use, and CCE findings. Multivariable logistic and linear regressions with backward elimination were performed.

RESULTS

We analyzed 451 CCE procedures with a completion rate of 51.9%. The completion rate was higher among older participants (odds ratio [OR] 1.54, 95% confidence interval [CI] 1.04-2.28, P = 0.03) and participants with a changed stool pattern (OR 2.27, 95% CI 1.20-4.30, P = 0.01). Participants with a history of abdominal surgery had a lower completion rate (OR 0.54, 95% CI 0.36-0.80, P = 0.003). Participants with higher BMI had faster stomach, small bowel, and total transit times (β = -0.10, P = 0.01; β = -0.14, P = 0.001; β = -0.12, P = 0.01). A faster small bowel transit was found in participants with a changed stool pattern (β = -0.08, P = 0.049) and the use of metoclopramide (β = -0.14, P = 0.001). Participants with high fiber intake had a slower colonic transit (β = 0.11, P = 0.03).

DISCUSSION

Younger age, unchanged stool pattern, history of abdominal surgery, low BMI, and high fiber intake resulted in slower CCE transit times and lower completion rates. In future practice, these factors can be considered to adjust preparation protocols.

Influence of Organic Solvents and β-cyclodextrins on Capillary Zone Electrophoresis Separation of Five Biogenic Amines and Two B Vitamins

The effects of organic modifiers—alcohols (methanol, isopropanol), acetonitrile, and tetrahydrofuran—and β-cyclodextrins in capillary zone electrophoresis were investigated using a test mixture containing five biogenic amines important from the human health point of view—serotonin, dopamine, adrenaline, noradrenaline, and tyramine—and two B vitamins—thiamine and pyridoxine. The simultaneous addition of tetrahydrofuran and isopropanol was found to improve the resolution of determined analytes and enable effective separation of analytes with very similar electromigration characteristics migrating as one peak (dopamine and serotonin). The developed and optimised separation method based on capillary zone electrophoresis and ultraviolet detection was capable to achieve detection limits at the concentration level in the range of 0.15 to 1.25 μg/mL−1. The developed method was also characterised by other favourable validation parameters, such as linearity (r 2 > 0.99), accuracy (82.9–117.8% for the intraday measurements, and 87.6–119.2% for the interday measurements), and precision (intraday relative standard deviation in the range of 0.4–15.5%, interday relative standard deviation in the range of 0.9–18.3%). The method was finally applied to investigate the stability of the analytes in model water matrix samples under various storage conditions.

Polydopamine Nanoparticle-Mediated Dopaminergic Immunoregulation in Colitis

Despite immunosuppression is critical for reducing immune overactivation, existing immunosuppressive agents are largely restricted by low inhibition efficiencies and unpredictable off-target toxicities. Here, the use of the dopaminergic system is reported to suppress hyperactive immune responses in local inflamed tissues. A polydopamine nanoparticular immunosuppressant (PDNI) is synthesized to stimulate regulatory T (Treg) cells and directly inhibit T helper 1 (Th1), Th2, and Th17 cells. Moreover, PDNI can inhibit the activation of dendritic cells to upregulate the ratio of Treg/Th17, which assists the reversion of inflammatory responses. The application of dopaminergic immunoregulation is further disclosed by combining with gut microbiota modulation for treating inflammations. The combination is implemented by coating living beneficial bacteria with PDNI. Following oral delivery, coated bacteria not only suppress the hyperactive immune responses but also positively modulate the gut microbiome in mice characterized with colitis. Strikingly, the combination demonstrates enhanced treatment efficacies in comparison with clinical aminosalicylic acid in two murine models of colitis. The use of the dopaminergic system opens a window to intervene immune responses and provides a versatile platform for the development of new therapeutics for treating inflammatory diseases.

Putative regulation of macrophage-mediated inflammation by catestatin

Catestatin (CST) is a bioactive cleavage product of the neuroendocrine prohormone chromogranin A (CgA). Recent findings show that CST can exert anti-inflammatory and antiadrenergic effects by suppressing the inflammatory actions of mammalian macrophages. However, recent findings also suggest that macrophages themselves are major CST producers. Here, we hypothesize that macrophages produce CST in an inflammation-dependent manner and thereby might self-regulate inflammation in an autocrine fashion. CST is associated with pathological conditions hallmarked by chronic inflammation, including autoimmune, cardiovascular, and metabolic disorders. Since intraperitoneal injection of CST in mouse models of diabetes and inflammatory bowel disease has been reported to be beneficial for mitigating disease, we posit that CST should be further investigated as a candidate target for treating certain inflammatory diseases.

Identification of gene candidates associated with Irritable bowel syndrome

Background/Aim: Irritable bowel syndrome (IBS) belongs to the gastrointestinal disorders characterised by abdominal discomfort and pain, altered constipation, diarrhoea and stomach distension. The aim was to assess relationship between the selected genetic polymorphisms with IBS, their combined genotype effect as well as to assess a difference in the distribution of allele and genotype frequencies of selected loci between case and control group. Methods: This was a prospective study which included 29 participants, 20 individuals diagnosed with IBS based on Rome III criteria and 9 healthy individuals. The study analysed the selected genetic polymorphisms as possible risk factors for IBS according to the model of the case-control study. Genotyping was performed for FKBP5, DRD2 and DAT polymorphisms qualified as risk factors for IBS in previous researches. Results: The results revealed a significant association between DAT polymorphism with IBS, both, at the allelic level (p = 0.006) and genotype level (p = 0.031). Individuals with 434 allelic variant in the genotype have six time higher probability for developing IBS, in comparison to the individuals without this allelic variant. The statistical association between other analysed polymorphism and IBS was not reached. The analysis of combined effects of selected polymorphisms revealed no association with IBS, except FKBP5 and DAT which result was at the level of statistical significance (p = 0.05). Conclusion: Further analysis which would include DAT polymorphism with larger sample size, as well as other genes involved in dopamine neurotransmitter system would be of great interest to define closer conclusion of IBS aetiology.

Co-occurrence of gut microbiota dysbiosis and bile acid metabolism alteration is associated with psychological disorders in Crohn's disease

This study aims to elucidate the relationships between gut microbiota, bile acid metabolism, and psychological comorbidity in Crohn's disease (CD). We profiled the fecal microbiota composition and quantified the bile acid pool of 39 CD patients and 14 healthy controls using 16S rRNA gene sequencing and liquid chromatography-tandem mass spectrometry, respectively. Significant reductions in the secondary bile acids, LCA and DCA, were found in both the feces and serum samples of CD patients, while the concentration of 7-DHCA was particularly higher in the serum of CD patients with psychological disorders. The fecal levels of HDCA and 12-DHCA of the CD patients were inversely correlated with their Self-Rated Depression Scale (SDS) scores, whereas the serum level of 7-DHCA was positively correlated with the SDS scores. In addition, the fecal levels of TDCA, TLCA, and TβMCA showed a positive correlation with the Self-Rated Anxiety Scale (SAS) scores. The fecal microbiota biodiversity was particularly declined in CD patients with psychological disorders. An enrichment of Ruminococcus gnavus in CD patients may cause psychological disorders by affecting the microbiota-gut-brain axis via its ability to degrade the gut barrier, regulate the tryptophan-kynurenine metabolism, and modulate bile acid metabolism. In addition, the overabundant Enterobacteriaceae and Lachnospiraceae in CD patients may contribute to psychological comorbidity via dysregulating their bile acids metabolism. Taken together, changes in the gut microbiota composition may cooperate with alterations in the bile acid metabolism that are involved in the development of psychological disorders in CD.

An In Vitro Approach to Studying the Microbial Community and Impact of Pre and Probiotics under Anorexia Nervosa Related Dietary Restrictions

Individuals with anorexia nervosa (AN) often suffer psychological and gastrointestinal problems consistent with a dysregulated gut microbial community. Psychobiotics have been postulated to modify microbiota and improve mental well-being and gut symptoms, but there is currently a lack of evidence for such approaches in AN. The aim of this study was to use an in vitro colonic model to evaluate the impact of dietary restrictions associated with AN on the intestinal ecosystem and to assess the impact of pre and probiotic intervention. Bacteriology was quantified using flow cytometry combined with fluorescence in situ hybridisation and metabolic end products (including neurotransmitters) by gas chromatography and liquid chromatography mass spectrometry Consistent with previous research, the nutritional changes significantly reduced total microbiota and metabolites compared with healthy conditions. Pre and probiotic supplementation on restricted conditions enhanced the microbial community and modulated metabolic activity to resemble that of a healthy diet. The model system indicates that nutritional changes associated with AN can impact the microbial community, and that these changes can, at least in part, be restored through the use of pre and probiotic interventions.

Fluorescent Nanozeolite Receptors for the Highly Selective and Sensitive Detection of Neurotransmitters in Water and Biofluids

The design and preparation of synthetic binders (SBs) applicable for small biomolecule sensing in aqueous media remains very challenging. SBs designed by the lock-and-key principle can be selective for their target analyte but usually show an insufficient binding strength in water. In contrast, SBs based on symmetric macrocycles with a hydrophobic cavity can display high binding affinities but generally suffer from indiscriminate binding of many analytes. Herein, a completely new and modular receptor design strategy based on microporous hybrid materials is presented yielding zeolite-based artificial receptors (ZARs) which reversibly bind the neurotransmitters serotonin and dopamine with unprecedented affinity and selectivity even in saline biofluids. ZARs are thought to uniquely exploit both the non-classical hydrophobic effect and direct non-covalent recognition motifs, which is supported by in-depth photophysical, and calorimetric experiments combined with full atomistic modeling. ZARs are thermally and chemically robust and can be readily prepared at gram scales. Their applicability for the label-free monitoring of important enzymatic reactions, for (two-photon) fluorescence imaging, and for high-throughput diagnostics in biofluids is demonstrated. This study showcases that artificial receptor based on microporous hybrid materials can overcome standing limitations of synthetic chemosensors, paving the way towards personalized diagnostics and metabolomics.

Review article: Physical and psychological comorbidities associated with irritable bowel syndrome

Irritable bowel syndrome (IBS) is one of the most common gastrointestinal disorders encountered by physicians in primary and secondary care. Patients with IBS commonly present with various extraintestinal complaints, which account for a substantial clinical and economic burden. The common extraintestinal comorbidities associated with IBS include anxiety, depression, somatisation, fibromyalgia, chronic fatigue syndrome, chronic pelvic pain, interstitial cystitis, sexual dysfunction and sleep disturbance. The presence of comorbidity in IBS poses a diagnostic and therapeutic challenge with patients frequently undergoing unnecessary investigations and interventions, including surgery. This review discusses the different physical and psychological comorbidities associated with IBS, the shared pathophysiological mechanisms and potential management strategies.

Headache and immunological/autoimmune disorders: a comprehensive review of available epidemiological evidence with insights on potential underlying mechanisms

Several lines of evidence support a role of the immune system in headache pathogenesis, with particular regard to migraine. Firstly, alterations in cytokine profile and in lymphocyte subsets have been reported in headache patients. Secondly, several genetic and environmental pathogenic factors seem to be frequently shared by headache and immunological/autoimmune diseases. Accordingly, immunological alterations in primary headaches, in particular in migraine, have been suggested to predispose some patients to the development of immunological and autoimmune diseases. On the other hand, pathogenic mechanisms underlying autoimmune disorders, in some cases, seem to favour the onset of headache. Therefore, an association between headache and immunological/autoimmune disorders has been thoroughly investigated in the last years. The knowledge of this possible association may have relevant implications in the clinical practice when deciding diagnostic and therapeutic approaches. The present review summarizes findings to date regarding the plausible relationship between headache and immunological/autoimmune disorders, starting from a description of immunological alteration of primary headaches, and moving onward to the evidence supporting a potential link between headache and each specific autoimmune/immunological disease.

Microbes, metabolites and (synaptic) malleability, oh my! The effect of the microbiome on synaptic plasticity

The microbiome influences the emotional and cognitive phenotype of its host, as well as the neurodevelopment and pathophysiology of various brain processes and disorders, via the well‐established microbiome–gut–brain axis. Rapidly accumulating data link the microbiome to severe neuropsychiatric disorders in humans, including schizophrenia, Alzheimer's and Parkinson's. Moreover, preclinical work has shown that perturbation of the microbiome is closely associated with social, cognitive and behavioural deficits. The potential of the microbiome as a diagnostic and therapeutic tool is currently undercut by a lack of clear mechanistic understanding of the microbiome–gut–brain axis. This review establishes the hypothesis that the mechanism by which this influence is carried out is synaptic plasticity – long‐term changes to the physical and functional neuronal structures that enable the brain to undertake learning, memory formation, emotional regulation and more. By examining the different constituents of the microbiome–gut–brain axis through the lens of synaptic plasticity, this review explores the diverse aspects by which the microbiome shapes the behaviour and mental wellbeing of the host. Key elements of this complex bi‐directional relationship include neurotransmitters, neuronal electrophysiology, immune mediators that engage with both the central and enteric nervous systems and signalling cascades that trigger long‐term potentiation of synapses. The importance of establishing mechanistic correlations along the microbiome–gut–brain axis cannot be overstated as they hold the potential for furthering current understanding regarding the vast fields of neuroscience and neuropsychiatry. This review strives to elucidate the promising theory of microbiome‐driven synaptic plasticity in the hope of enlightening current researchers and inspiring future ones.

The role of gut and genital microbiota and the estrobolome in endometriosis, infertility and chronic pelvic pain

BACKGROUND

Endometriosis is a chronic, burdensome condition that is historically understudied. Consequently, there is a lack of understanding of the etiology of the disease and its associated symptoms, including infertility and chronic pelvic pain (CPP). Endometriosis development is influenced by estrogen metabolism and inflammation, which are modulated by several factors including the microbiome and the estrobolome (the collection of genes encoding estrogen-metabolizing enzymes in the gut microbiome). Therefore, there is increasing interest in understanding the role of microbiota in endometriosis etiology.

OBJECTIVE AND RATIONALE

To date, there is no cure for endometriosis and treatment options often are ineffective. This manuscript will review the potential relationship between the microbiome and endometriosis, infertility and CPP and highlight the available data on the microbiome in relation to endometriosis and its related symptoms. The overarching goal of this manuscript is to inform future microbiome research that will lead to a deeper understanding of the etiology of the disease and possible diagnostic modalities and treatments. The potential impact of the microbiome on estrogen regulation modulated by the estrobolome, as well as inflammation and other endometriosis-promoting mechanisms within the genital tract, will be reviewed. The methodological limitations of microbiome-related studies will be critically assessed to provide improved guidelines for future microbiome and clinical studies.

SEARCH METHODS

PubMed databases were searched using the following keywords: endometriosis AND microbiome, infertility AND microbiome, pelvic pain AND microbiome, IVF (in-vitro fertilization) AND microbiome, endometriosis AND infertility. Clinical and preclinical animal trials that were eligible for review, and related to microbiome and endometriosis, infertility or CPP were included. All available manuscripts were published in 2002-2021.

OUTCOMES

In total, 28 clinical and 6 animal studies were included in the review. In both human and animal studies, bacteria were enriched in endometriosis groups, although there was no clear consensus on specific microbiota compositions that were associated with endometriosis, and no studies included infertility or CPP with endometriosis. However, bacterial vaginosis-associated bacteria and Lactobacillus depletion in the cervicovaginal microbiome were associated with endometriosis and infertility in the majority (23/28) of studies. Interpretation of endometrial studies is limited owing to a variety of methodological factors, discussed in this review. In addition, metadata outlining antibiotic usage, age, race/ethnicity, menopausal status and timing of sample collection in relation to diagnosis of endometriosis was not consistently reported. Animal studies (6/6) support a bidirectional relationship between the gut microbiota and endometriosis onset and progression.

WIDER IMPLICATIONS

There is evidence that a dysbiotic gut or genital microbiota is associated with multiple gynecologic conditions, with mounting data supporting an association between the microbiome and endometriosis and infertility. These microbiomes likely play a role in the gut-brain axis, which further supports a putative association with the spectrum of symptoms associated with endometriosis, including infertility and CPP. Collectively, this review highlights the demand for more rigorous and transparent methodology and controls, consistency across the field, and inclusion of key demographic and clinical characteristics of disease and comparison participants. Rigorous study designs will allow for a better understanding of the potential role of the microbiome in endometriosis etiology and the relationship to other disorders of the female reproductive tract.

Potential Contribution of the Intestinal Microbiome to Phenethylamine-Induced Hyperthermia

Phenethylamines (e.g., methamphetamine) are a common source of drug toxicity. Phenethylamine-induced hyperthermia (PIH) can activate a cascade of events that may result in rhabdomyolysis, coagulopathy, and even death. Here, we review recent evidence that suggests a potential link between the gut-brain axis and PIH. Within the preoptic area of the hypothalamus, phenethylamines lead to changes in catecholamine levels, that activate the sympathetic nervous system (SNS) and increase the peripheral levels of norepinephrine (NE), resulting in: (1) the loss of heat dissipation through α1 adrenergic receptor (α1-AR)-mediated vasoconstriction, (2) heat generation through β-AR activation and subsequent free fatty acid (FFA) activation of uncoupling proteins (UCPs) in brown and white adipose tissue, and (3) alteration of the gut microbiome and its link to the gut-brain axis. Recent studies have shown that phenethylamine derivatives can influence the composition of the gut microbiome and thus its metabolic potential. Phenethylamines increase the relative level of Proteuswhich has been linked to enhanced NE turnover. Bidirectional fecal microbial transplants (FMT) between PIH-tolerant and PIH-naïve rats demonstrated that the transplantation of gut microbiome can confer phenotypic hyperthermic and tolerant responses to phenethylamines. These phenethylamine-mediated changes in the gut microbiome were also associated with epigenetic changes in the mediators of thermogenesis. Given the significant role that the microbiome has been shown to play in the maintenance of body temperature, we outline current studies demonstrating the effects of phenethylamines on the gut microbiome and how these microbiome changes may mechanistically contribute to alterations in body temperature.

High-coverage metabolomics uncovers microbiota-driven biochemical landscape of interorgan transport and gut-brain communication in mice

The mammalian gut harbors a complex and dynamic microbial ecosystem: the microbiota. While emerging studies support that microbiota regulates brain function with a few molecular cues suggested, the overall biochemical landscape of the “microbiota-gut-brain axis” remains largely unclear. Here we use high-coverage metabolomics to comparatively profile feces, blood sera, and cerebral cortical brain tissues of germ-free C57BL/6 mice and their age-matched conventionally raised counterparts. Results revealed for all three matrices metabolomic signatures owing to microbiota, yielding hundreds of identified metabolites including 533 altered for feces, 231 for sera, and 58 for brain with numerous significantly enriched pathways involving aromatic amino acids and neurotransmitters. Multicompartmental comparative analyses single out microbiota-derived metabolites potentially implicated in interorgan transport and the gut-brain axis, as exemplified by indoxyl sulfate and trimethylamine-N-oxide. Gender-specific characteristics of these landscapes are discussed. Our findings may be valuable for future research probing microbial influences on host metabolism and gut-brain communication.

The gut microbiota harbours neuroactive potential with links to neurological disorders. Here, the authors apply global metabolomics with an integrated annotation strategy to comparatively profile fecal, blood serum and cerebral cortical brain tissues of eight-week-old germ-free mice vs. age-matched specific-pathogen-free mice, providing a snapshot of the metabolome status linked to the gut-brain axis.

Xiaoyao Pill improves the Affective Dysregulation of Sleep-deprived Female Mice by inhibiting Brain Injury and regulating the Content of Monoamine Neurotransmitter

BACKGROUND

Sleep curtailment is a serious problem in many societies. Clinical evidence has shown that sleep deprivation is associated with mood dysregulation, formation of false memory, cardio-metabolic risk factors and outcomes, inflammatory disease risk, and all-cause mortality. The affective disorder dysregulation caused by insufficient sleep has become an increasingly serious health problem. However, to date, not much attention has been paid to the mild affective dysregulation caused by insufficient sleep, and there is no clear and standard therapeutic method to treat it. The Xiaoyao Pill is a classic Chinese medicinal formula, with the effect of dispersing stagnated hepatoqi, invigorating the spleen, and nourishing the blood. Therefore, it is most commonly used to treat gynecological diseases in China. In the present study, the effects of the Xiaoyao Pill on affective dysregulation of sleep-deprived mice and its underlying molecular mechanisms were investigated.

METHODS

Forty adult female mice were used in the present study. The sleep deprivation model was established by improving the multi-platform water environment method. After 7 consecutive days of sleep deprivation, the mice were administrated low (LXYP, 0.32mg/kg) and high (HXYP, 0.64 mg/kg) doses of the Xiaoyao Pill for two weeks. Then, the body weight, behavioral deficits, and histopathology were evaluated. Meanwhile, the expression of c-fos protein and the concentrations of monoamine neurotransmitters in the hippocampus and prefrontal cortex were determined after two weeks of treatment.

RESULTS

Xiaoyao Pill treatment significantly increased body weight and sucrose consumption and decreased the irritability scores of the sleep-deprived mice. Meanwhile, Xiaoyao Pill treatment prevented brain injury and inhibited the expression of c-fos protein in the hippocampus and prefrontal cortex. In addition, HXYP treatment significantly upregulated the levels of NE in the hippocampus and prefrontal cortex (p < 0.01). LXYP treatment significantly up-regulated the levels of 5-HT in the prefrontal cortex. Meanwhile, both HXYP and LXYP treatment significantly up-regulated the levels of DA in the prefrontal cortex (p < 0.05 or p < 0.01) of sleep-deprived mice.

CONCLUSIONS

The present study demonstrates that Xiaoyao Pill treatment prevented the behavioral deficits of mice induced by sleep deprivation by promoting the recovery of brain tissue injury and up-regulating the levels of NE, 5-HT, and DA in the brain tissue.

Microbiota-Gut-Brain Axis and Epilepsy: A Review on Mechanisms and Potential Therapeutics

The gut-brain axis refers to the bidirectional communication between the gut and brain, and regulates intestinal homeostasis and the central nervous system via neural networks and neuroendocrine, immune, and inflammatory pathways. The development of sequencing technology has evidenced the key regulatory role of the gut microbiota in several neurological disorders, including Parkinson's disease, Alzheimer's disease, and multiple sclerosis. Epilepsy is a complex disease with multiple risk factors that affect more than 50 million people worldwide; nearly 30% of patients with epilepsy cannot be controlled with drugs. Interestingly, patients with inflammatory bowel disease are more susceptible to epilepsy, and a ketogenic diet is an effective treatment for patients with intractable epilepsy. Based on these clinical facts, the role of the microbiome and the gut-brain axis in epilepsy cannot be ignored. In this review, we discuss the relationship between the gut microbiota and epilepsy, summarize the possible pathogenic mechanisms of epilepsy from the perspective of the microbiota gut-brain axis, and discuss novel therapies targeting the gut microbiota. A better understanding of the role of the microbiota in the gut-brain axis, especially the intestinal one, would help investigate the mechanism, diagnosis, prognosis evaluation, and treatment of intractable epilepsy.

Symptomatic use of carbidopa in autonomic disorders

Carbidopa is being explored as a novel therapy for hyperadrenergic symptoms of autonomic disorders, due to its potential to decrease peripheral catecholamine levels. This study retrospectively characterized patients in our autonomic clinic who were prescribed carbidopa for open label treatment of autonomic symptoms. 23 patients were included; approximately half had postural orthostatic tachycardia syndrome. Those with documented plasma catecholamines had elevated standing norepinephrine. Patients typically had multiple comorbidities and multiple failed therapies. 19 took carbidopa (typically 25 mg three times daily); 12 continued it for longer than 3 months. 11 patients reported better symptom control with carbidopa, most commonly tremor and gastrointestinal dysfunction. 4 patients reported side effects. In this small retrospective study, carbidopa was well tolerated in patients with dysautonomia, and half reported symptomatic benefit. Larger, placebo-controlled trials are warranted for further investigation of this therapy.

Beta-blockers reduce intestinal permeability and early mortality following traumatic brain injury in Drosophila

Traumatic brain injury (TBI) frequently leads to non-neurological consequences such as intestinal permeability. The beta-blocker drug labetalol, which inhibits binding of catecholamine neurotransmitters to adrenergic receptors, reduces intestinal permeability in a rat TBI model. Using a Drosophila melanogaster TBI model, we previously found a strong positive correlation between intestinal permeability and mortality within 24 hours of TBI in a standard laboratory line (w¹¹¹⁸ ) and across genetically diverse inbred lines from the Drosophila Genetic Reference Panel (DGRP). Here, we report that feeding injured w¹¹¹⁸ flies the beta-blockers labetalol and metoprolol reduced intestinal permeability and mortality. Additionally, metoprolol reduced intestinal permeability when 18 DGRP fly lines were analyzed in aggregate, but neither beta-blocker affected mortality. These data indicate that the mechanism underlying disruption of the intestinal barrier by adrenergic signaling following TBI is conserved between humans and flies and that mortality following TBI in flies is not strictly dependent on disruption of the intestinal barrier. Thus, the fly TBI model is useful for shedding light on the mechanism and consequences of adrenergic signaling between the brain and intestine following TBI in humans.

Mucosa-associated specific bacterial species disrupt the intestinal epithelial barrier in the autism phenome

Gut-Brain Axis provides a bidirectional communicational route, an imbalance of which can have pathophysiological consequences. Differential gut microbiome studies have become a frontier in autism research, affecting 85% of autistic children. The present study aims to understand how gut microbiota of autism subjects differ from their neurotypical counterparts. This study would help to identify the abundance of bacterial signature species in autism and their associated metabolites.

16S rRNA metagenomic sequence datasets of 30 out of 206 autism subjects were selected from the American Gut Project Archive. First, the taxonomic assignment was inferred by similarity-based methods using the Quantitative Insights into Microbial Ecology (QIIME) toolkit. Next, species abundance was characterized, and a co-occurrence network was built to infer species interaction using measures of diversity. Thirdly, statistical parameters were incorporated to validate the findings. Finally, the identification of metabolites associated with these bacterial signature species connects with biological processes in the host through pathway analysis.

Gut microbiome data revealed Akkermansia sp. and Faecalibacterium prausnitzii to be statistically lower in abundance in autistic children than their neurotypical peers with a five and two-fold decrease, respectively. While Prevotella sp. and Sutterella sp. showed a five and a two-fold increase in cases, respectively. The constructed pathway revealed succinate and butyrate as the significant metabolites for the bacterial signature species identified.

The present study throws light on the role of mucosa-associated bacterial species: Veillonella sp., Prevotella sp., Akkermansia sp., Sutterella sp., Faecalibacterium prausnitzii, Lactobacillus sp., which can act as diagnostic criteria for detection of gut dysbiosis in autism.

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Bacteroidetes/Firmicutes ratio is significantly higher in autistic children due to differential lifestyle habits in the present study.

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Mucosal associated bacteria, namely Prevotella, Akkermansia, Veillonella, Sutterella, and Faecalibacterium are indicated as potential diagnostic criteria for gut dysbiosis in autism.

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Elevated Proteobacteria levels is contrasting with reported inclinations towards gut related functionality in mouse models.

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The authors report unique link for autism and Prevotella sp. phylotype with higher relative abundance in autism cases.

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Pathway revealed succinate and butyrate as the significant metabolites for the identified bacterial signatures.

Dopamine Modulates Drosophila Gut Physiology, Providing New Insights for Future Gastrointestinal Pharmacotherapy

Dopamine has a variety of physiological roles in the gastrointestinal tract (GI) through binding to Drosophila dopamine D1-like receptors (DARs) and/or adrenergic receptors and has been confirmed as one of the enteric neurotransmitters. To gain new insights into what could be a potential future promise for GI pharmacology, we used Drosophila as a model organism to investigate the effects of dopamine on intestinal physiology and gut motility. GAL4/UAS system was utilized to knock down specific dopamine receptors using specialized GAL4 driver lines targeting neurons or enterocytes cells to identify which dopamine receptor controls stomach contractions. DARs (Dop1R1 and Dop1R2) were shown by immunohistochemistry to be strongly expressed in all smooth muscles in both larval and adult flies, which could explain the inhibitory effect of dopamine on GI motility. Adult males' gut peristalsis was significantly inhibited by knocking down dopamine receptors Dop1R1, Dop1R2, and Dop2R, but female flies' gut peristalsis was significantly repressed by knocking down only Dop1R1 and Dop1R2. Our findings also showed that dopamine drives PLC-β translocation from the cytoplasm to the plasma membrane in enterocytes for the first time. Overall, these data revealed the role of dopamine in modulating Drosophila gut physiology, offering us new insights for the future gastrointestinal pharmacotherapy of neurodegenerative diseases associated with dopamine deficiency.

Why use nutraceutical strategies for the Irritable Bowel Syndrome

Irritable bowel syndrome (IBS) is a chronic functional bowel disorder, often stress-related, identified by many abdominal symptoms, the most important of which is the chronic visceral abdominal pain. Therefore, IBS commonly impairs the quality of life of patients, moreover it is frequently linked to depressive and anxiety symptoms. The treatment of IBS primarily focuses on symptoms relief. Unfortunately, up to now, no efficacious therapies have been found. Therefore, it would be important to develop new anti-IBS interventions. The aim of this brief review is to summarize the current evidence of nutraceutical supplementation in IBS treatment, with probiotics, prebiotics, synbiotics, butyrate, palmitoylethanolamide and colostrum. Since nutraceutics are over the counter products, the review has the purpose to better inform the medicinal chemist and the practitioner about the possible benefit mechanisms and the many advantages that these therapies offer. All of these compounds present multiple mechanisms of action, such as restoring the physiological microbiota, potentiating gastrointestinal barrier's function, immunomodulatory, anti-inflammatory and antinociceptive activities. From the literature data it results that these compounds are not only capable to improve IBS symptomatology, but mainly display an optimal safety and tolerability profile. Although extensive studies must be carried out to reinforce the evidences from the so far limited clinical trials, the supplementation with these compounds may be useful considering the warnings of prescription medicines for special populations of patients, such as elders, youngsters, or patients who need a combination therapy. Finally, the nutraceutical approach may improve adherence to treatment, given its better acceptance by the patients compared to pharmacological therapy.

Gut dysbiosis, defective autophagy and altered immune responses in neurodegenerative diseases: Tales of a vicious cycle

The human microbiota comprises trillions of symbiotic microorganisms and is involved in regulating gastrointestinal (GI), immune, nervous system and metabolic homeostasis. Recent observations suggest a bidirectional communication between the gut microbiota and the brain via immune, circulatory and neural pathways, termed the Gut-Brain Axis (GBA). Alterations in gut microbiota composition, such as seen with an increased number of pathobionts and a decreased number of symbionts, termed gut dysbiosis or microbial intestinal dysbiosis, plays a prominent role in the pathogenesis of central nervous system (CNS)-related disorders. Clinical reports confirm that GI symptoms often precede neurological symptoms several years before the development of neurodegenerative diseases (NDDs). Pathologically, gut dysbiosis disrupts the integrity of the intestinal barrier leading to ingress of pathobionts and toxic metabolites into the systemic circulation causing GBA dysregulation. Subsequently, chronic neuroinflammation via dysregulated immune activation triggers the accumulation of neurotoxic misfolded proteins in and around CNS cells resulting in neuronal death. Emerging evidence links gut dysbiosis to the aggravation and/or spread of proteinopathies from the peripheral nervous system to the CNS and defective autophagy-mediated proteinopathies. This review summarizes the current understanding of the role of gut microbiota in NDDs, and highlights a vicious cycle of gut dysbiosis, immune-mediated chronic neuroinflammation, impaired autophagy and proteinopathies, which contributes to the development of neurodegeneration in Alzheimer's disease, Parkinson's disease, Huntington's disease, multiple sclerosis, amyotrophic lateral sclerosis and frontotemporal lobar degeneration. We also discuss novel therapeutic strategies targeting the modulation of gut dysbiosis through prebiotics, probiotics, synbiotics or dietary interventions, and faecal microbial transplantation (FMT) in the management of NDDs.

The Multifaceted Role of Serotonin in Intestinal Homeostasis

The monoamine serotonin, 5-hydroxytryptamine (5-HT), is a remarkable molecule with conserved production in prokaryotes and eukaryotes and a wide range of functions. In the gastrointestinal tract, enterochromaffin cells are the most important source for 5-HT production. Some intestinal bacterial species are also able to produce 5-HT. Besides its role as a neurotransmitter, 5-HT acts on immune cells to regulate their activation. Several lines of evidence indicate that intestinal 5-HT signaling is altered in patients with inflammatory bowel disease. In this review, we discuss the current knowledge on the production, secretion, and signaling of 5-HT in the intestine. We present an inventory of intestinal immune and epithelial cells that respond to 5-HT and describe the effects of these signaling processes on intestinal homeostasis. Further, we detail the mechanisms by which 5-HT could affect inflammatory bowel disease course and describe the effects of interventions that target intestinal 5-HT signaling.

A Microbiome-Driven Approach to Combating Depression During the COVID-19 Pandemic

The significant stressors brought about and exacerbated by COVID-19 are associated with startling surges in mental health illnesses, specifically those related to depressive disorders. Given the huge impact of depression on society, and an incomplete understanding of impactful therapeutics, we have examined the current literature surrounding the microbiome and gut-brain axis to advance a potential complementary approach to address depression and depressive disorders that have increased during the COVID-19 pandemic. While we understand that the impact of the human gut microbiome on emotional health is a newly emerging field and more research needs to be conducted, the current evidence is extremely promising and suggests at least part of the answer to understanding depression in more depth may lie within the microbiome. As a result of these findings, we propose that a microbiome-based holistic approach, which involves carefully annotating the microbiome and potential modification through diet, probiotics, and lifestyle changes, may address depression. This paper's primary purpose is to shed light on the link between the gut microbiome and depression, including the gut-brain axis and propose a holistic approach to microbiome modification, with the ultimate goal of assisting individuals to manage their battle with depression through diet, probiotics, and lifestyle changes, in addition to offering a semblance of hope during these challenging times.

Cell Death-Osis of Dopaminergic Neurons and the Role of Iron in Parkinson's Disease

Significance: There is still no cure for neurodegenerative diseases, such as Parkinson's disease (PD). Current treatments are based on the attempt to reduce dopaminergic neuronal loss, and multidisciplinary approaches have been used to provide only a temporary symptoms' relief. In addition to the difficulties of drugs developed against PD to access the brain, the specificity of those inhibitory compounds could be a concern. This because neurons might degenerate by activating distinct signaling pathways, which are often initiated by the same stimulus. Recent Advances: Apoptosis, necroptosis, and ferroptosis were shown to significantly contribute to PD progression and, so far, are the main death programs described as capable to alter brain homeostasis. Their activation is characterized by different biochemical and morphological features, some of which might even share the same molecular players. Critical Issues: If there is a pathological need to engage, in PD, multiple death programs, sequentially or simultaneously, is not clear yet. Possibly the activation of apoptosis, necroptosis, and/or ferroptosis correlates to different PD stages and symptom severities. This would imply that the efficacy of therapeutic approaches against neuronal death might depend on the death program they target and the relevance of this death pathway on a specific PD phase. Future Directions: In this review, we describe the molecular mechanisms underlying the activation of apoptosis, necroptosis, and ferroptosis in PD. Understanding the interrelationship between different death pathways' activation in PD is of utmost importance for the development of therapeutic approaches against disease progression. Antioxid. Redox Signal. 35, 453-473.

Deoxynivalenol interferes with intestinal motility via injuring the contractility of enteric smooth muscle cells: A novel hazard to the gastrointestinal tract by environmental toxins

Deoxynivalenol (DON) is a prevalent Fusarium mycotoxin, occurs predominantly in the global environment, especially in cereals, animal feed and food commodities. The widespread contamination causes a serious risk to human and animal health. DON usually impairs weight gain, which is presumably from its capacity to reduce feed intake by interfering with intestinal motility. To clarify the role of smooth muscle cells (SMCs) contractility in intestinal motility and growth inhibition caused by DON, twelve weaned piglets were firstly divided into two groups to feed control or Fusarium mycotoxin-contaminated (MC) diet. Results showed that the final body weight, average daily gain and average daily feed intake were significantly reduced in piglets fed the MC diet. Exposure to the MC diet also significantly decreased the thickness of smooth muscle layer and SMCs contractile markers expression (myosin heavy chain 11, smooth muscle actin gamma 2, transgelin, calponin 1) in jejunum and ileum of piglets. Furthermore, oral DON supplementation (3 mg/kg body weight) to mice in six consecutive days could significantly inhibit the upper intestinal transit, impede normal defecation and downregulate SMCs contractile markers expression in small intestine. Finally, we generated a porcine enteric smooth muscle cell line (PISMC), and found that DON could depress its contractility by decreasing PISMC proliferation, migration and contractile markers expression. In conclusion, these findings in vivo and in vitro suggest that DON, as a common environmental toxin, can not only reduce proliferative and motile phenotype, but also decrease contractile apparatus components (contractile markers expression) in SMCs, which in turn influences SMCs contractility and then interferes with intestinal motility and growth performance.

Microbiota-Gut-Brain Communication in the SARS-CoV-2 Infection

The coronavirus disease of 2019 (COVID-19) is an infectious disease caused by severe acute respiratory syndrome 2 (SARS-CoV-2). In addition to pneumonia, individuals affected by the disease have neurological symptoms. Indeed, SARS-CoV-2 has a neuroinvasive capacity. It is known that the infection caused by SARS-CoV-2 leads to a cytokine storm. An exacerbated inflammatory state can lead to the blood-brain barrier (BBB) damage as well as to intestinal dysbiosis. These changes, in turn, are associated with microglial activation and reactivity of astrocytes that can promote the degeneration of neurons and be associated with the development of psychiatric disorders and neurodegenerative diseases. Studies also have been shown that SARS-CoV-2 alters the composition and functional activity of the gut microbiota. The microbiota-gut-brain axis provides a bidirectional homeostatic communication pathway. Thus, this review focuses on studies that show the relationship between inflammation and the gut microbiota-brain axis in SARS-CoV-2 infection.

Role of Amine Neurotransmitters and Their Receptors in Skin Pigmentation: Therapeutic Implication

Skin pigmentation can occur due to increased melanin, including melanocyte proliferation, melanin biosynthesis, or melanocyte migration. There are many factors that influence the melanin production process, but the role of neurotransmitters in this process is still unclear. We found that histamine and serotonin influence the different stages of melanogenesis and melanogenesis, which increase melanogenesis. Since then, several related papers have been published, and from these papers, it has been recognised that the role of neurotransmitters in skin-pigment-related diseases needs to be summarised. By introducing the role of neurotransmitters in the regulation of various pigment disorders, including vitiligo and melasma, through this review, many researchers can be expected to try to apply neurotransmitter-related agonists and antagonists as treatments for skin pigment disorders.

Neurotransmitter Profiles Are Altered in the Gut and Brain of Mice Mono-Associated with Bifidobacterium dentium

Background: Accumulating evidence indicates that the gut microbiota can synthesize neurotransmitters as well as impact host-derived neurotransmitter levels. In the past, it has been challenging to decipher which microbes influence neurotransmitters due to the complexity of the gut microbiota. Methods: To address whether a single microbe, Bifidobacterium dentium, could regulate important neurotransmitters, we examined Bifidobacteria genomes and explored neurotransmitter pathways in secreted cell-free supernatant using LC-MS/MS. To determine if B. dentium could impact neurotransmitters in vivo, we mono-associated germ-free mice with B. dentium ATCC 27678 and examined fecal and brain neurotransmitter concentrations. Results: We found that B. dentium possessed the enzymatic machinery to generate γ-aminobutyric acid (GABA) from glutamate, glutamine, and succinate. Consistent with the genome analysis, we found that B. dentium secreted GABA in a fully defined microbial media and elevated fecal GABA in B. dentium mono-associated mice compared to germ-free controls. We also examined the tyrosine/dopamine pathway and found that B. dentium could synthesize tyrosine, but could not generate L-dopa, dopamine, norepinephrine, or epinephrine. In vivo, we found that B. dentium mono-associated mice had elevated levels of tyrosine in the feces and brain. Conclusions: These data indicate that B. dentium can contribute to in vivo neurotransmitter regulation.

Alkylammonium Cation Affinities of Nitrogenated Organobases: The Roles of Hydrogen Bonding and Proton Transfer

Alkylammonium cation affinities of 64 nitrogen-containing organobases, as well as the respective proton transfer processes from the alkylammonium cations to the base, have been computed in the gas phase by using DFT methods. The guanidine bases show the highest proton transfer values (191.9-233 kJ mol^-1 ) whereas the cis-2,2'-biimidazole presents the largest affinity towards the alkylammonium cations (>200 kJ mol^-1 ) values. The resulting data have been compared with the experimentally reported proton affinities of the studied nitrogen-containing organobases revealing that the propensity of an organobase for the proton transfer process increases linearly with its proton affinity. This work can provide a tool for designing senors for bioactive compounds containing amino groups that are protonated at physiological pH.

Altering the gut microbiome to potentially modulate behavioral manifestations in autism spectrum disorders: A systematic review

There is a potential association between gastrointestinal (GI) symptoms and the severity of autism spectrum disorder (ASD). Given this correlation, the possible impact of probiotics and prebiotics have been explored in research studies to modify the gut microbiome and ameliorate behavioral manifestations of ASD via modulating the gut-brain-microbiome axis. This systematic review focuses on the interplay between these factors in altering the behavioral manifestations of ASD. Probiotic supplementation tended to mitigate some of the behavioral manifestations of ASD, with less of a discernible trend on the microbiome level. Studies supplementing multiple probiotic species, such as microbiota transfer therapy, or including prebiotics performed better than single strain supplementation. Our analysis suggests that gut dysbiosis may increase intestinal permeability, leading to more severe GI symptoms and a systemic inflammatory response, which can alter permeability across the blood-brain barrier and synaptogenesis in the brain. Future studies are warranted to understand the precise contribution of altering gut microbiome on clinical manifestations of ASD that will open up avenues to develop preventive and treatment modalities.

Influence of a High-Impact Multidimensional Rehabilitation Program on the Gut Microbiota of Patients with Multiple Sclerosis

Multiple sclerosis (MS) is a neurodegenerative inflammatory condition mediated by autoreactive immune processes. Due to its potential to influence host immunity and gut-brain communication, the gut microbiota has been suggested to be involved in the onset and progression of MS. To date, there is no definitive cure for MS, and rehabilitation programs are of the utmost importance, especially in the later stages. However, only a few people generally participate due to poor support, knowledge, and motivation, and no information is available on gut microbiota changes. Herein we evaluated the potential of a brief high-impact multidimensional rehabilitation program (B-HIPE) in a leisure environment to affect the gut microbiota, mitigate MS symptoms and improve quality of life. B-HIPE resulted in modulation of the MS-typical dysbiosis, with reduced levels of pathobionts and the replenishment of beneficial short-chain fatty acid producers. This partial recovery of a eubiotic profile could help counteract the inflammatory tone typically observed in MS, as supported by reduced circulating lipopolysaccharide levels and decreased populations of pro-inflammatory lymphocytes. Improved physical performance and fatigue relief were also found. Our findings pave the way for integrating clinical practice with holistic approaches to mitigate MS symptoms and improve patients’ quality of life.

Gastrointestinal pathophysiology during endurance exercise: endocrine, microbiome, and nutritional influences

Gastrointestinal symptoms are abundant among athletes engaging in endurance exercise, particularly when exercising in increased environmental temperatures, at higher intensities, or over extremely long distances. It is currently thought that prolonged ischemia, mechanical damage to the epithelial lining, and loss of epithelial barrier integrity are likely contributors of gastrointestinal (GI) distress during bouts of endurance exercise, but due to the many potential causes and sporadic nature of symptoms this phenomenon has proven difficult to study. In this review, we cover known factors that contribute to GI distress symptoms in athletes during exercise, while further attempting to identify novel avenues of future research to help elucidate mechanisms leading to symptomology. We explore the link between the intestinal microbiome, the integrity of the gut epithelia, and add detail on gut hormone and peptide secretion that could potentially contribute to GI distress symptoms in athletes. The influence of nutrition and dietary supplementation strategies are also detailed, where much research has opened up new ideas and potential mechanisms for understanding gut pathophysiology during exercise. The etiology of gastrointestinal symptoms during endurance exercise is multi-factorial with neuroendocrine, microbial, and nutritional factors likely contributing to specific, individualized symptoms. Recent work in previously unexplored areas of both microbiome and gut peptide secretion are pertinent areas for future work, and the numerous supplementation strategies explored to date have provided insight into physiological mechanisms that may be targetable to reduce the incidence and severity of gastrointestinal symptoms in athletes.

Atremorine in Parkinson's disease: From dopaminergic neuroprotection to pharmacogenomics

Atremorine is a novel bioproduct obtained by nondenaturing biotechnological processes from a genetic species of Vicia faba. Atremorine is a potent dopamine (DA) enhancer with powerful effects on the neuronal dopaminergic system, acting as a neuroprotective agent in Parkinson's disease (PD). Over 97% of PD patients respond to a single dose of Atremorine (5 g, p.o.) 1 h after administration. This response is gender-, time-, dose-, and genotype-dependent, with optimal doses ranging from 5 to 20 g/day, depending upon disease severity and concomitant medication. Drug-free patients show an increase in DA levels from 12.14 ± 0.34 pg/ml to 6463.21 ± 1306.90 pg/ml; and patients chronically treated with anti-PD drugs show an increase in DA levels from 1321.53 ± 389.94 pg/ml to 16,028.54 ± 4783.98 pg/ml, indicating that Atremorine potentiates the dopaminergic effects of conventional anti-PD drugs. Atremorine also influences the levels of other neurotransmitters (adrenaline, noradrenaline) and hormones which are regulated by DA (e.g., prolactin, PRL), with no effect on serotonin or histamine. The variability in Atremorine-induced DA response is highly attributable to pharmacogenetic factors. Polymorphic variants in pathogenic (SNCA, NUCKS1, ITGA8, GPNMB, GCH1, BCKDK, APOE, LRRK2, ACMSD), mechanistic (DRD2), metabolic (CYP2D6, CYP2C9, CYP2C19, CYP3A4/5, NAT2), transporter (ABCB1, SLC6A2, SLC6A3, SLC6A4) and pleiotropic genes (APOE) influence the DA response to Atremorine and its psychomotor and brain effects. Atremorine enhances DNA methylation and displays epigenetic activity via modulation of the pharmacoepigenetic network. Atremorine is a novel neuroprotective agent for dopaminergic neurons with potential prophylactic and therapeutic activity in PD.

Technician-Scored Stool Consistency Spans the Full Range of the Bristol Scale in a Healthy US Population and Differs by Diet and Chronic Stress Load

BACKGROUND

Prior studies of adults with constipation or diarrhea suggest that dietary intake, physical activity, and stress may affect stool consistency. However, the influence of these factors is unresolved and has not been investigated in healthy adults.

OBJECTIVES

We assessed the relations of technician-scored stool consistency in healthy adults with self-reported diet, objectively monitored physical activity, and quantifiable markers of stress.

METHODS

Stool consistency was scored by an independent technician using the Bristol Stool Form Scale (BSFS) to analyze samples provided by healthy adults, aged 18-65 y, BMI 18-44 kg/m2, in the USDA Nutritional Phenotyping Study (n = 364). A subset of participants (n = 109) were also asked to rate their sample using the BSFS. Dietary intake was assessed with two to three 24-h recalls completed at home and energy expenditure from physical activity was monitored using an accelerometer in the 7-d period preceding the stool collection. Stress was measured using the Wheaton Chronic Stress Inventory and allostatic load (AL). Statistical and machine learning analyses were conducted to determine which dietary, physiological, lifestyle, and stress factors differed by stool form.

RESULTS

Technician-scored BSFS scores were significantly further (P = 0.003) from the central score (mean ± SEM distance: 1.41 ± 0.089) than the self-reported score (1.06 ± 0.086). Hard stool was associated with higher (P = 0.005) intake of saturated fat (13.8 ± 0.40 g/1000 kcal) than was normal stool (12.5 ± 0.30 g/1000 kcal). AL scores were lower for normal stool (2.49 ± 0.15) than for hard (3.07 ± 0.18) (P = 0.009) or soft stool (2.89 ± 0.18) (P = 0.049). Machine learning analyses revealed that various dietary components, physiological characteristics, and stress hormones predicted stool consistency.

CONCLUSIONS

Technician-scored stool consistency differed by dietary intake and stress hormones, but not by physical activity, in healthy adults.This trial was registered at clincialtrials.gov as NCT02367287.

Exploring the Role and Potential of Probiotics in the Field of Mental Health: Major Depressive Disorder

The field of probiotic has been exponentially expanding over the recent decades with a more therapeutic-centered research. Probiotics mediated microbiota modulation within the microbiota–gut–brain axis (MGBA) have been proven to be beneficial in various health domains through pre-clinical and clinical studies. In the context of mental health, although probiotic research is still in its infancy stage, the promising role and potential of probiotics in various mental disorders demonstrated via in-vivo and in-vitro studies have laid a strong foundation for translating preclinical models to humans. The exploration of the therapeutic role and potential of probiotics in major depressive disorder (MDD) is an extremely noteworthy field of research. The possible etio-pathological mechanisms of depression involving inflammation, neurotransmitters, the hypothalamic–pituitary–adrenal (HPA) axis and epigenetic mechanisms potentially benefit from probiotic intervention. Probiotics, both as an adjunct to antidepressants or a stand-alone intervention, have a beneficial role and potential in mitigating anti-depressive effects, and confers some advantages compared to conventional treatments of depression using anti-depressants.

Metabolomics-Guided Hypothesis Generation for Mechanisms of Intestinal Protection by Live Biotherapeutic Products

The use of live biotherapeutic products (LBPs), including single strains of beneficial probiotic bacteria or consortiums, is gaining traction as a viable option to treat inflammatory-mediated diseases like inflammatory bowel disease (IBD). However, LBPs' persistence in the intestine is heterogeneous since many beneficial bacteria lack mechanisms to tolerate the inflammation and the oxidative stress associated with IBD. We rationalized that optimizing LBPs with enhanced colonization and persistence in the inflamed intestine would help beneficial bacteria increase their bioavailability and sustain their beneficial responses. Our lab developed two bioengineered LBPs (SBT001/BioPersist and SBT002/BioColoniz) modified to enhance colonization or persistence in the inflamed intestine. In this study, we examined colon-derived metabolites via ultra-high performance liquid chromatography-mass spectrometry in colitic mice treated with either BioPersist or BioColoniz as compared to their unmodified parent strains (Escherichia coli Nissle 1917 [EcN] and Lactobacillus reuteri, respectively) or to each other. BioPersist administration resulted in lowered concentrations of inflammatory prostaglandins, decreased stress hormones such as adrenaline and corticosterone, increased serotonin, and decreased bile acid in comparison to EcN. In comparison to BioColoniz, BioPersist increased serotonin and antioxidant production, limited bile acid accumulation, and enhanced tissue restoration via activated purine and pyrimidine metabolism. These data generated several novel hypotheses for the beneficial roles that LBPs may play during colitis.

In Pursuit of Healthy Aging: Effects of Nutrition on Brain Function

Consuming a balanced, nutritious diet is important for maintaining health, especially as individuals age. Several studies suggest that consuming a diet rich in antioxidants and anti-inflammatory components such as those found in fruits, nuts, vegetables, and fish may reduce age-related cognitive decline and the risk of developing various neurodegenerative diseases. Numerous studies have been published over the last decade focusing on nutrition and how this impacts health. The main objective of the current article is to review the data linking the role of diet and nutrition with aging and age-related cognitive decline. Specifically, we discuss the roles of micronutrients and macronutrients and provide an overview of how the gut microbiota-gut-brain axis and nutrition impact brain function in general and cognitive processes in particular during aging. We propose that dietary interventions designed to optimize the levels of macro and micronutrients and maximize the functioning of the microbiota-gut-brain axis can be of therapeutic value for improving cognitive functioning, particularly during aging.

Voluntary binge-patterned alcohol drinking and sex-specific influences on monoamine-related neurochemical signatures in the mouse gut and brain

BACKGROUND

Altered monoamine (i.e., serotonin, dopamine, and norepinephrine) activity following episodes of alcohol abuse plays key roles not only in the motivation to ingest ethanol, but also physiological dysfunction related to its misuse. Although monoamine activity is essential for physiological processes that require coordinated communication across the gut-brain axis (GBA), relatively little is known about how alcohol misuse may affect monoamine levels across the GBA. Therefore, we evaluated monoamine activity across the mouse gut and brain following episodes of binge-patterned ethanol drinking.

METHODS

Monoamine and select metabolite neurochemical concentrations were analyzed by ultra-high-performance liquid chromatography in gut and brain regions of female and male C57BL/6J mice following "Drinking in the Dark" (DID), a binge-patterned ethanol ingestion paradigm.

RESULTS

First, we found that alcohol access had an overall small effect on gut monoamine-related neurochemical concentrations, primarily influencing dopamine activity. Second, neurochemical patterns between the small intestine and the striatum were correlated, adding to recent evidence of modulatory activity between these areas. Third, although alcohol access robustly influenced activity in brain areas in the mesolimbic dopamine system, binge exposure also influenced monoaminergic activity in the hypothalamic region. Finally, sex differences were observed in the concentrations of neurochemicals within the gut, which was particularly pronounced in the small intestine.

CONCLUSION

Together, these data provide insights into the influence of alcohol abuse and biological sex on monoamine-related neurochemical changes across the GBA, which could have important implications for GBA function and dysfunction.

Study of Haloperidol for Abdominal Pain in the Emergency Department (SHAPE)

Introduction

Intravenous haloperidol has been shown to decrease milligram morphine equivalents (MME) of analgesia and reduce hospital admissions for diabetic gastroparesis. The objective of this study was to evaluate whether haloperidol decreases MME for the treatment of non-specific abdominal pain diagnoses in the emergency department (ED), including gastroparesis, cyclic vomiting, cannabinoid hyperemesis syndrome, and unspecified abdominal pain. The primary outcome compared the difference in MME between encounters. Secondary outcomes included admission rate, pain scores, length of stay, rescue therapy administration, and adverse effects.

Methods

This retrospective chart review included patients ≥ 18 years old who presented to the ED. Patients must have had ≥ 2 ED encounters for abdominal pain, one in which they received conventional therapy with opioids (C-encounter), and the other in which they received haloperidol (H-encounter). Agitated patients were excluded. Seventy-five patients were needed to detect a 3 MME difference with 80% power and two-sided alpha of 0.05.

Results

We analyzed 107 patients with self-matched encounters. The median dose of haloperidol administered was 5.0 milligrams (mg) (interquartile range [IQR] 2.0 – 5.0). C-encounters had significantly more MME administered than H-encounters (median 5.7 mg [IQR 4.0 – 8.0] vs 0.0 mg [IQR 0.0 – 2.5], P < 0.001). These results remained significant despite route of haloperidol administration. C-encounters had higher rates of rescue therapy administration than H-encounters, (56% vs 33.6%, P < 0.001). There were higher rates of ketorolac administration in the H-encounter (P = 0.02).

Conclusion

Encounters in which patients received haloperidol and ketorolac for abdominal pain had a statistically significant reduction in MME administered and lower rates of rescue therapy administration than encounters in which patients were treated with opioids.

The distinct roles of monoamines in multiple sclerosis: A bridge between the immune and nervous systems?

The monoaminergic neurotransmitters dopamine, noradrenaline, and serotonin are pivotal actors of the interplay between the nervous and the immune system due to their ability of binding to cell-receptors of both systems, crucially regulating their function within the central nervous system and the periphery. As monoamines are dysfunctional in many neurological and psychiatric diseases, they have been successfully used as pharmacological targets. Multiple sclerosis (MS) is one of the best examples of neurological disease caused by an altered interaction between the nervous and immune system and emerging evidence supports a dysregulation of monoaminergic systems in the pathogenesis of MS, secondary to both inflammation-induced reduction of monoamines' synthesis and structural damage to monoaminergic pathways within the brain. Here we review the evidence for monoamines being key mediators of neuroimmune interaction, affecting MS pathogenesis and course. Moreover, we discuss how the reduction/dysfunction of monoamines in MS may contribute to some clinical features typical of the disease, particularly fatigue and depression. Finally, we summarize different drugs targeting monoamines that are currently under evaluation for their potential efficacy to treat MS, as well as to alleviate fatigue and depression in MS.

Deep Transcranial Magnetic Stimulation Affects Gut Microbiota Composition in Obesity: Results of Randomized Clinical Trial

Growing evidence highlights the crucial role of gut microbiota in affecting different aspects of obesity. Considering the ability of deep transcranial magnetic stimulation (dTMS) to modulate the cortical excitability, the reward system, and, indirectly, the autonomic nervous system (ANS), we hypothesized a potential role of dTMS in affecting the brain-gut communication pathways, and the gut microbiota composition in obesity. In a hospital setting, 22 subjects with obesity (5 M, 17 F; 44.9 ± 2.2 years; BMI 37.5 ± 1.0 kg/m²) were randomized into three groups receiving 15 sessions (3 per week for 5 weeks) of high frequency (HF), low frequency (LF) dTMS, or sham stimulation. Fecal samples were collected at baseline and after 5 weeks of treatment. Total bacterial DNA was extracted from fecal samples using the QIAamp DNA Stool Mini Kit (Qiagen, Italy) and analyzed by a metagenomics approach (Ion Torrent Personal Genome Machine). After 5 weeks, a significant weight loss was found in HF (HF: −4.1 ± 0.8%, LF: −1.9 ± 0.8%, sham: −1.3 ± 0.6%, p = 0.042) compared to LF and sham groups, associated with a decrease in norepinephrine compared to baseline (HF: −61.5 ± 15.2%, p < 0.01; LF: −31.8 ± 17.1%, p < 0.05; sham: −35.8 ± 21.0%, p > 0.05). Furthermore, an increase in Faecalibacterium (+154.3% vs. baseline, p < 0.05) and Alistipes (+153.4% vs. baseline, p < 0.05) genera, and a significant decrease in Lactobacillus (−77.1% vs. baseline, p < 0.05) were found in HF. Faecalibacterium variations were not significant compared to baseline in the other two groups (LF: +106.6%, sham: +27.6%; p > 0.05) as well as Alistipes (LF: −54.9%, sham: −15.1%; p > 0.05) and Lactobacillus (LF: −26.0%, sham: +228.3%; p > 0.05) variations. Norepinephrine change significantly correlated with Bacteroides (r² = 0.734; p < 0.05), Eubacterium (r² = 0.734; p < 0.05), and Parasutterella (r² = 0.618; p < 0.05) abundance variations in HF. In conclusion, HF dTMS treatment revealed to be effective in modulating gut microbiota composition in subjects with obesity, reversing obesity-associated microbiota variations, and promoting bacterial species representative of healthy subjects with anti-inflammatory properties.