Gut microbiota varies by opioid use, circulating leptin and oxytocin in African American men with diabetes and high burden of chronic disease

The role of morphine- and fentanyl-induced impairment of intestinal epithelial antibacterial activity in dysbiosis and its impact on the microbiota-gut-brain axis

Recent evidence suggests that chronic exposure to opioid analgesics such as morphine disrupts the intestinal epithelial layer and causes intestinal dysbiosis. Depleting gut bacteria can preclude the development of tolerance to opioid-induced antinociception, suggesting an important role of the gut-brain axis in mediating opioid effects. The mechanism underlying opioid-induced dysbiosis, however, remains unclear. Host-produced antimicrobial peptides (AMPs) are critical for the integrity of the intestinal epithelial barrier as they prevent the pathogenesis of the enteric microbiota. Here, we report that chronic morphine or fentanyl exposure reduces the antimicrobial activity in the ileum, resulting in changes in the composition of bacteria. Fecal samples from morphine-treated mice had increased levels of Akkermansia muciniphila with a shift in the abundance ratio of Firmicutes and Bacteroidetes. Fecal microbial transplant (FMT) from morphine-naïve mice or oral supplementation with butyrate restored (a) the antimicrobial activity, (b) the expression of the antimicrobial peptide, Reg3γ, (c) prevented the increase in intestinal permeability and (d) prevented the development of antinociceptive tolerance in morphine-dependent mice. Improved epithelial barrier function with FMT or butyrate prevented the enrichment of the mucin-degrading A. muciniphila in morphine-dependent mice. These data implicate impairment of the antimicrobial activity of the intestinal epithelium as a mechanism by which opioids disrupt the microbiota-gut-brain axis.

Effect of cinnamon spice on continuously monitored glycemic response in adults with prediabetes: a 4-week randomized controlled crossover trial

BACKGROUND

Previous clinical studies showing that cinnamon spice lowers blood glucose concentrations had inconsistent results.

OBJECTIVES

To determine the effect of daily cinnamon spice supplementation in an amount commonly used for seasoning on glucose concentrations in adults with obesity and prediabetes.

METHODS

Following a 2-wk run-in period of maintaining a low polyphenol/fiber diet, 18 participants with obesity and prediabetes underwent a 10-wk randomized, controlled, double-blind, crossover trial (mean age 51.1 y; mean fasting plasma glucose 102.9 mg/dL). The participants were randomly assigned to take cinnamon (4 g/d) or placebo for 4-wk, followed by a 2-wk washout period, and then crossed over to the other intervention for an additional 4-wk. Glucose changes were measured with continuous glucose monitoring. Oral glucose tolerance testing immediately following ingestion of cinnamon or placebo was performed at 4-time points to assess their acute effects both at the baseline and end of each intervention phase. Digestive symptom logs were obtained daily.

RESULTS

There were 694 follow-up days with 66,624 glucose observations. When compared with placebo, 24-h glucose concentrations were significantly lower when cinnamon was administered [mixed-models; effect size (ES) = 0.96; 95 % confidence interval (CI): -2.9, -1.5; P < 0.001]. Similarly, the mean net-area-under-the-curve (netAUC) for glucose was significantly lower than for placebo when cinnamon was given (over 24 h; ES = -0.66; 95 % CI: 2501.7, 5412.1, P = 0.01). Cinnamon supplementation resulted in lower glucose peaks compared with placebo (Δpeak 9.56 ± 9.1 mg/dL compared with 11.73 ± 8.0 mg/dL; ES = -0.57; 95 % CI: 0.8, 3.7, P = 0.027). Glucose-dependent-insulinotropic-polypeptide concentrations increased during oral glucose tolerance testing + cinnamon testing (mixed-models; ES = 0.51; 95 % CI: 1.56, 100.1, P = 0.04), whereas triglyceride concentrations decreased (mixed-models; ES = 0.55; 95 % CI: -16.0, -1.6, P = 0.02). Treatment adherence was excellent in both groups (cinnamon: 97.6 ± 3.4 % compared with placebo: 97.9 ± 3.7 %; ES = -0.15; 95 % CI: -1.8, 0.2, P = 0.5). No differences were found in digestive symptoms (abdominal pain, borborygmi, bloating, excess flatus, and stools/day) between cinnamon and placebo groups.

CONCLUSIONS

Cinnamon, a widely available and low-cost supplement, may contribute to better glucose control when added to the diet in people who have obesity-related prediabetes. This trial was registered at clinicaltrials.gov as NCT04342624.

Impact of Opioid Use on Duration of Therapy and Overall Survival for Patients with Advanced Non-Small Cell Lung Cancer Treated with Immune Checkpoint Inhibitors

Immune checkpoint inhibitors (ICI) have significantly improved outcomes in advanced non-small cell lung cancer (NSCLC). We evaluated the effect of opioid use on outcomes in patients receiving ICI either alone or with chemotherapy. We conducted a retrospective review of 209 patients with advanced NSCLC who received an ICI at the University of Virginia between 1 February 2015 and 1 January 2020. We performed univariate and multivariate analyses to evaluate the impact of opioid use on duration of therapy (DOT) and overall survival (OS). Patients with no or low opioid use (n = 172) had a median DOT of 12.2 months (95% CI: 6.9-17.4) compared to 1.9 months (95% CI: 1.8-2.0) for those with high opioid use (n = 37, HR 0.26 95% CI: 0.17-0.40, p < 0.001). Patients with no or low opioid use had a median OS of 22.6 months (95% CI: 14.8-30.4) compared to 3.8 months (95% CI: 2.7-4.9) for those with high opioid use (HR 0.26 95% CI: 0.17-0.40 p < 0.001). High opioid use was associated with a shorter DOT and worse OS. This difference remained significant when accounting for possible confounding variables. These data warrant investigation of possible mechanistic interactions between opioids, tumor progression, and ICIs, as well as prospective evaluation of opioid-sparing pain management strategies, where possible.

Opioid trail: Tracking contributions to opioid use disorder from host genetics to the gut microbiome

Opioid use disorder (OUD) is a worldwide public health crisis with few effective treatment options. Traditional genetics and neuroscience approaches have provided knowledge about biological mechanisms that contribute to OUD-related phenotypes, but the complexity and magnitude of effects in the brain and body remain poorly understood. The gut-brain axis has emerged as a promising target for future therapeutics for several psychiatric conditions, so characterizing the relationship between host genetics and the gut microbiome in the context of OUD will be essential for development of novel treatments. In this review, we describe evidence that interactions between host genetics, the gut microbiome, and immune signaling likely play a key role in mediating opioid-related phenotypes. Studies in humans and model organisms consistently demonstrated that genetic background is a major determinant of gut microbiome composition. Furthermore, the gut microbiome is susceptible to environmental influences such as opioid exposure. Additional work focused on gene by microbiome interactions will be necessary to gain improved understanding of their effects on OUD-related behaviors.

The bidirectional relationship between opioids and the gut microbiome: Implications for opioid tolerance and clinical interventions

Opioids are widely used in treating patients with acute and chronic pain; however, this class of drugs is also commonly abused. Opioid use disorder and associated overdoses are becoming more prevalent as the opioid crisis continues. Chronic opioid use is associated with tolerance, which decreases the efficacy of opioids over time, but also puts individuals at risk of fatal overdoses. Therefore, it is essential to identify strategies to reduce opioid tolerance in those that use these agents. The gut microbiome has been found to play a critical role in opioid tolerance, with opioids causing dysbiosis of the gut, and changes in the gut microbiome impacting opioid tolerance. These changes in turn have a detrimental effect on the gut microbiome, creating a positive feedback cycle. We review the bidirectional relationship between the gut microbiome and opioid tolerance, discuss the role of modulation of the gut microbiome as a potential therapeutic option in opioid-induced gut dysbiosis, and suggest opportunities for further research and clinical interventions.

Multi-omics analysis revealing the interplay between gut microbiome and the host following opioid use

Opioid crisis is an ongoing epidemic since the past several decades in the United States. Opioid use-associated microbial dysbiosis is emerging as a key regulator of intestinal homeostasis and behavioral responses to opioid. However, the mechanistic insight into the role of microbial community in modulating host response is unavailable. To uncover the role of opioid-induced dysbiosis in disrupting intestinal homeostasis we utilized whole genome sequencing, untargeted metabolomics, and mRNA sequencing to identify changes in microbiome, metabolome, and host transcriptome respectively. Morphine treatment resulted in significant expansion of Parasuterella excrementihominis, Burkholderiales bacterium 1_1_47, Enterococcus faecalis, Enterorhabdus caecimuris and depletion of Lactobacillus johnsonii. These changes correlated with alterations in lipid metabolites and flavonoids. Significant alteration in microbial metabolism (metabolism of lipids, amino acids, vitamins and cofactors) and increased expression of virulence factors and biosynthesis of lipopolysaccharides (LPS) and lipoteichoic acid (LTA) were observed in microbiome of morphine-treated animals. In concurrence with changes in microbiome and metabolome extensive changes in innate and adaptive immune response, lipid metabolism, and gut barrier dysfunction were observed in the host transcriptome. Microbiome depleted mice displayed lower levels of inflammation, immune response and tissue destruction compared to mice harboring a dysbiotic microbiome in response to morphine treatment, thus establishing dysbiotic microbiome as mediator of morphine gut pathophysiology. Integrative analysis of multi-omics data highlighted the associations between Parasutterella excrementihominis, Burkholderiales bacterium 1_1_47, Enterococcus faecalis, Enterorhabdus caecimuris and altered levels of riboflavin, flavonoids, and lipid metabolites including phosphocholines, carnitines, bile acids, and ethanolamines with host gene expression changes involved in inflammation and barrier integrity of intestine. Omic analysis also highlighted the role of probiotic bacteria Lactobacillus johnsonii, metabolites flavonoids and riboflavin that were depleted with morphine as important factors for intestinal homeostasis. This study presents for the first time ever an interactive view of morphine-induced changes in microbial metabolism, strain level gut microbiome analysis and comprehensive view of changes in gut transcriptome. We also identified areas of potential therapeutic interventions to limit microbial dysbiosis and present a unique resource to the opioid research community.

Total Astragalus saponins can reverse type 2 diabetes mellitus-related intestinal dysbiosis and hepatic insulin resistance in vivo

Objective

Intestinal flora homeostasis in rats with type 2 diabetes mellitus (T2DM) was evaluated to explore the effects of total Astragalus saponins (TAS) on hepatic insulin resistance (IR).

Methods

Six-week-old male Sprague-Dawley rats were fed high-fat and high-sugar diet for 4 weeks and intraperitoneally injected with streptozotocin to induce T2DM, and they were then randomly divided into control, model, metformin, and TAS groups. Stool, serum, colon, and liver samples were collected after 8 weeks of drug administration for relevant analyses.

Results

TAS reduced fasting blood glucose, 2-hour postprandial blood glucose, area under the curve of oral glucose tolerance test, glycated serum protein, homeostasis model assessment of insulin resistance, total cholesterol, triglyceride, and low-density lipoprotein cholesterol levels in T2DM rats but increased insulin, C-peptide, and high-density lipoprotein cholesterol levels. Moreover, TAS improved the morphology and structure of liver and colon tissues and improved the composition of the intestinal microbiome and bacterial community structure at different taxonomic levels. In addition, TAS increased the protein expression of hepatic IRS-1, PI3K, PDK1, and p-AKT and decreased the protein expression of p-GSK-3β. Meanwhile, TAS increased the mRNA expression of liver PDK1, PI3K, and GS and decreased the mRNA expression of GSK-3β.

Conclusion

TAS can ameliorate T2DM-related abnormal glucose and blood lipid metabolism, intestinal dysbiosis, and IR.

Gut microbiota profiles in two New Zealand cohorts with overweight and prediabetes: a Tū Ora/PREVIEW comparative study

Obesity-related metabolic diseases such as type 2 diabetes (T2D) are major global health issues, affecting hundreds of millions of people worldwide. The underlying factors are both diverse and complex, incorporating biological as well as cultural considerations. A role for ethnicity - a measure of self-perceived cultural affiliation which encompasses diet, lifestyle and genetic components - in susceptibility to metabolic diseases such as T2D is well established. For example, Asian populations may be disproportionally affected by the adverse 'TOFI' (Thin on the Outside, Fat on the Inside) profile, whereby outwardly lean individuals have increased susceptibility due to excess visceral and ectopic organ fat deposition. A potential link between the gut microbiota and metabolic disease has more recently come under consideration, yet our understanding of the interplay between ethnicity, the microbiota and T2D remains incomplete. We present here a 16S rRNA gene-based comparison of the fecal microbiota of European-ancestry and Chinese-ancestry cohorts with overweight and prediabetes, residing in New Zealand. The cohorts were matched for mean fasting plasma glucose (FPG: mean ± SD, European-ancestry: 6.1 ± 0.4; Chinese-ancestry: 6.0 ± 0.4 mmol/L), a consequence of which was a significantly higher mean body mass index in the European group (BMI: European-ancestry: 37.4 ± 6.8; Chinese-ancestry: 27.7 ± 4.0 kg/m2; p < 0.001). Our findings reveal significant microbiota differences between the two ethnicities, though we cannot determine the underpinning factors. In both cohorts Firmicutes was by far the dominant bacterial phylum (European-ancestry: 93.4 ± 5.5%; Chinese-ancestry: 79.6 ± 10.4% of 16S rRNA gene sequences), with Bacteroidetes and Actinobacteria the next most abundant. Among the more abundant (≥1% overall relative sequence abundance) genus-level taxa, four zero-radius operational taxonomic units (zOTUs) were significantly higher in the European-ancestry cohort, namely members of the Subdoligranulum, Blautia, Ruminoclostridium, and Dorea genera. Differential abundance analysis further identified a number of additional zOTUs to be disproportionately overrepresented across the two ethnicities, with the majority of taxa exhibiting a higher abundance in the Chinese-ancestry cohort. Our findings underscore a potential influence of ethnicity on gut microbiota composition in the context of individuals with overweight and prediabetes.

Effects of metformin on the gut microbiota: A systematic review

BACKGROUND

The gut microbiota is increasingly recognized as a crucial factor in human health and disease. Metformin, a commonly prescribed medication for type 2 diabetes, has been studied for its potential impact on the gut microbiota in preclinical models. However, the effects of metformin on the gut microbiota in humans remain uncertain.

SCOPE OF REVIEW

We conducted a systematic review of clinical trials and observational studies to assess the existing knowledge on the impact of metformin on the gut microbiota in humans. The review focused on changes in bacterial composition and diversity following metformin treatment.

MAJOR CONCLUSIONS

Thirteen studies were included in the analysis. The results revealed alterations in the abundance of bacterial genera from various phyla, suggesting that metformin may selectively influence certain groups of bacteria in the gut microbiota. However, the effects on gut microbiota diversity were inconsistent across populations, with conflicting findings on changes in alpha and beta diversity measures. Overall, the use of metformin was associated with changes in the abundance of specific bacterial genera within the gut microbiota of human populations. However, the effects on gut microbiota diversity were not consistent, highlighting the need for further research to understand the underlying mechanisms and clinical significance of these changes.

Methadone maintenance treatment is more effective than compulsory detoxification in addressing gut microbiota dysbiosis caused by heroin abuse

Introduction

Heroin use disorder (HUD) is commonly accompanied by gut dysbiosis, but the roles of gut microbiota in HUD treatment, such as compulsory detoxification and methadone maintenance treatment (MMT), remain poorly understood.

Methods

In this study, we performed 16 s rDNA and whole metagenome sequencing to analyze the gut microbial profiles of HUD patients undergoing heroin addiction, heroin withdrawal (compulsory detoxification), and MMT.

Results

Our findings revealed that, compared to healthy controls, microbial diversity was significantly decreased in HUD patients who were in a state of heroin addiction and withdrawal, but not in those receiving MMT. We observed significant alterations in 10 bacterial phyla and 20 bacterial families in HUD patients, while MMT partially restored these changes. Whole metagenome sequencing indicated gut microbiota functions were significantly disrupted in HUD patients experiencing heroin addiction and withdrawal, but MMT was found to almost reverse these dysfunctions. In addition, we identified 24 featured bacteria at the genus level that could be used to effectively distinguish between healthy individuals and those with heroin addiction, heroin withdrawal, or receiving MMT. Furthermore, we found the relative abundance of Actinomyces, Turicibacter and Weissella were positively associated with the Hamilton Depression Scale score in different states of HUD patients.

Discussion

This study provides evidence from the gut microbiota perspective that MMT is a more effective approach than compulsory detoxification for HUD treatment.

Unveiling the potential pleiotropic effects of metformin in treating COVID-19: a comprehensive review

This review article explores the potential of metformin, a medication commonly used for type 2 diabetes, as an antiviral and anti-inflammatory agent in the context of coronavirus disease 2019 (COVID-19). Metformin has demonstrated inhibitory effects on the growth of SARS-CoV-2 in cell culture models and has shown promising results in reducing viral load and achieving undetectable viral levels in clinical trials. Additionally, metformin exhibits anti-inflammatory properties by reducing the production of pro-inflammatory cytokines and modulating immune cell function, which may help prevent cytokine storms associated with severe COVID-19. The drug's ability to regulate the balance between pro-inflammatory Th17 cells and anti-inflammatory Treg cells suggests its potential in mitigating inflammation and restoring T cell functionality. Furthermore, metformin's modulation of the gut microbiota, particularly changes in bacterial taxa and the production of short-chain fatty acids, may contribute to its therapeutic effects. The interplay between metformin, bile acids, the gut microbiome, glucagon-like peptide-1 secretion, and glycemic control has implications for the management of diabetes and potential interventions in COVID-19. By refreshing the current evidence, this review highlights the potential of metformin as a therapeutic option in the management of COVID-19, while also exploring its effects on the gut microbiome and immunometabolism.

The Role of Morphine-Induced Impairment of Intestinal Epithelial Antibacterial Activity in Dysbiosis and its Impact on the Microbiota-Gut-Brain Axis.. [PMID: 37503065 PMCID: PMC10371156 DOI: 10.21203/rs.3.rs-3084467/v2]

Recent evidence suggests that chronic exposure to opioid analgesics such as morphine disrupt the intestinal epithelial layer and cause intestinal dysbiosis. Inhibiting opioid-induced dysbiosis can preclude the development of tolerance to opioid-induced antinociception, suggesting an important role of the gut-brain axis in mediating opioid effects. However, the mechanism underlying opioid-induced dysbiosis remains unclear. Host-produced antimicrobial peptides (AMPs) are critical for the integrity of the intestinal epithelial barrier as they prevent the pathogenesis of the enteric microbiota. Here, we report that chronic morphine exposure reduces expression of the antimicrobial peptide, Regenerating islet-derived 3 gamma (Reg3γ), in the ileum resulting in reduced intestinal antimicrobial activity against Gram-positive bacteria, L. reuteri. Fecal samples from morphine-treated mice had reduced levels of the phylum, Firmicutes, concomitant with reduced levels of short-chain fatty acid, butyrate. Fecal microbial transplant (FMT) from morphine-naïve mice restored the antimicrobial activity, the expression of Reg3γ, and prevented the increase in intestinal permeability and the development of antinociceptive tolerance in morphine-dependent mice. Similarly, oral gavage with sodium butyrate dose-dependently reduced the development of antinociceptive tolerance, and prevented the downregulation of Reg3γ and the reduction in antimicrobial activity. The alpha diversity of the microbiome was also restored by oral butyrate in morphine-dependent mice. These data implicate impairment of the antimicrobial activity of the intestinal epithelium as a mechanism by which morphine disrupts the microbiota-gut-brain axis.

The Role of Morphine-Induced Impairment of Intestinal Epithelial Antibacterial Activity in Dysbiosis and its Impact on the Microbiota-Gut-Brain Axis

Recent evidence suggests that chronic exposure to opioid analgesics such as morphine disrupt the intestinal epithelial layer and cause intestinal dysbiosis. Inhibiting opioid-induced dysbiosis can preclude the development of tolerance to opioid-induced antinociception, suggesting an important role of the gut-brain axis in mediating opioid effects. However, the mechanism underlying opioid-induced dysbiosis remains unclear. Host-produced antimicrobial peptides (AMPs) are critical for the integrity of the intestinal epithelial barrier as they prevent the pathogenesis of the enteric microbiota. Here, we report that chronic morphine exposure reduces expression of the antimicrobial peptide, Regenerating islet-derived 3 gamma (Reg3γ), in the ileum resulting in reduced intestinal antimicrobial activity against Gram-positive bacteria, L. reuteri. Fecal samples from morphine-treated mice had reduced levels of the phylum, Firmicutes, concomitant with reduced levels of short-chain fatty acid, butyrate. Fecal microbial transplant (FMT) from morphine-naïve mice restored the antimicrobial activity, the expression of Reg3γ, and prevented the increase in intestinal permeability and the development of antinociceptive tolerance in morphine-dependent mice. Similarly, oral gavage with sodium butyrate dose-dependently reduced the development of antinociceptive tolerance, and prevented the downregulation of Reg3γ and the reduction in antimicrobial activity. The alpha diversity of the microbiome was also restored by oral butyrate in morphine-dependent mice. These data implicate impairment of the antimicrobial activity of the intestinal epithelium as a mechanism by which morphine disrupts the microbiota-gut-brain axis.

Effect of a 12-Week Polyphenol Rutin Intervention on Markers of Pancreatic β-Cell Function and Gut Microbiota in Adults with Overweight without Diabetes

Supplementation with prebiotic polyphenol rutin is a potential dietary therapy for type 2 diabetes prevention in adults with obesity, based on previous glycaemic improvement in transgenic mouse models. Gut microbiota are hypothesised to underpin these effects. We investigated the effect of rutin supplementation on pancreatic β-cell function measured as C-peptide/glucose ratio, and 16S rRNA gene-based gut microbiota profiles, in a cohort of individuals with overweight plus normoglycaemia or prediabetes. Eighty-seven participants were enrolled, aged 18-65 years with BMI of 23-35 kg/m2. This was a 12-week double-blind randomised controlled trial (RCT), with 3 treatments comprising (i) placebo control, (ii) 500 mg/day encapsulated rutin, and (iii) 500 mg/day rutin-supplemented yoghurt. A 2-h oral glucose tolerance test (OGTT) was performed at baseline and at the end of the trial, with faecal samples also collected. Compliance with treatment was high (~90%), but rutin in both capsule and dietary format did not alter pancreatic β-cell response to OGTT over 12 weeks. Gut bacterial community composition also did not significantly change, with Firmicutes dominating irrespective of treatment. Fasting plasma glucose negatively correlated with the abundance of the butyrate producer Roseburia inulinivorans, known for its anti-inflammatory capacity. This is the first RCT to investigate postprandial pancreatic β-cell function in response to rutin supplementation.

HIV, opioid use, and alterations to the gut microbiome: elucidating independent and synergistic effects

Background

The microbiome is essential to immune development, defense against pathogens, and modulation of inflammation. Microbial dysbiosis has been reported in various diseases including human immunodeficiency virus (HIV) and opioid use disorder (OUD). Notably, people living with HIV (PLWH) have been reported to both have higher rates of OUD and use opioids at higher rates than the general public. Thus, studying gut microbial alterations in people living with HIV and with OUD could elucidate mechanisms pertaining to how these conditions both shape and are shaped by the microbiome. However, to date few studies have investigated how HIV and OUD in combination impact the microbiome.

Aim of review

Here, we review previous studies outlining interactions between HIV, opioid use, and microbial dysbiosis and describe attempts to treat this dysbiosis with fecal microbial transplantation, probiotics, and dietary changes.

Key scientific concepts of review

While the limited number of studies prevent overgeneralizations; accumulating data suggest that HIV and opioid use together induce distinct alterations in the gut microbiome. Among the three existing preclinical studies of HIV and opioid use, two studies reported a decrease in Lachnospiraceae and Ruminococcaceae, and one study reported a decrease in Muribaculaceae in the combined HIV and opioid group relative to HIV-alone, opioid-alone, or control groups. These bacteria are known to modulate immune function, decrease colonic inflammation, and maintain gut epithelial barrier integrity in healthy individuals. Accordingly, modulation of the gut microbiome to restore gut homeostasis may be attempted to improve both conditions. While mixed results exist regarding treating dysbiosis with microbial restoration in PLWH or in those with opioid dependency, larger well-defined studies that can improve microbial engraftment in hosts hold much promise and should still be explored.

Combing fecal microbial community data to identify consistent obesity-specific microbial signatures and shared metabolic pathways

Obesity is associated with altered gut microbiome composition but data across different populations remain inconsistent. We meta-analyzed publicly available 16S-rRNA sequence datasets from 18 different studies and identified differentially abundant taxa and functional pathways of the obese gut microbiome. Most differentially abundant genera (Odoribacter, Oscillospira, Akkermansia, Alistipes, and Bacteroides) were depleted in obesity, indicating a deficiency of commensal microbes in the obese gut microbiome. From microbiome functional pathways, elevated lipid biosynthesis and depleted carbohydrate and protein degradation suggested metabolic adaptation to high-fat, low-carbohydrate, and low-protein diets in obese individuals. Machine learning models trained on the 18 studies were modest in predicting obesity with a median AUC of 0.608 using 10-fold cross-validation. The median AUC increased to 0.771 when models were trained in eight studies designed for investigating obesity-microbiome association. By meta-analyzing obesity-associated microbiota signatures, we identified obesity-associated depleted taxa that may be exploited to mitigate obesity and related metabolic diseases.

Design of the Building Research in CRC prevention (BRIDGE-CRC) trial: a 6-month, parallel group Mediterranean diet and weight loss randomized controlled lifestyle intervention targeting the bile acid-gut microbiome axis to reduce colorectal cancer risk among African American/Black adults with obesity

BACKGROUND

Among all racial/ethnic groups, people who identify as African American/Blacks have the second highest colorectal cancer (CRC) incidence in the USA. This disparity may exist because African American/Blacks, compared to other racial/ethnic groups, have a higher prevalence of risk factors for CRC, including obesity, low fiber consumption, and higher intakes of fat and animal protein. One unexplored, underlying mechanism of this relationship is the bile acid-gut microbiome axis. High saturated fat, low fiber diets, and obesity lead to increases in tumor promoting secondary bile acids. Diets high in fiber, such as a Mediterranean diet, and intentional weight loss may reduce CRC risk by modulating the bile acid-gut microbiome axis. The purpose of this study is to test the impact of a Mediterranean diet alone, weight loss alone, or both, compared to typical diet controls on the bile acid-gut microbiome axis and CRC risk factors among African American/Blacks with obesity. Because weight loss or a Mediterranean diet alone can reduce CRC risk, we hypothesize that weight loss plus a Mediterranean diet will reduce CRC risk the most.

METHODS

This randomized controlled lifestyle intervention will randomize 192 African American/Blacks with obesity, aged 45-75 years to one of four arms: Mediterranean diet, weight loss, weight loss plus Mediterranean diet, or typical diet controls, for 6 months (48 per arm). Data will be collected at baseline, mid-study, and study end. Primary outcomes include total circulating and fecal bile acids, taurine-conjugated bile acids, and deoxycholic acid. Secondary outcomes include body weight, body composition, dietary change, physical activity, metabolic risk, circulating cytokines, gut microbial community structure and composition, fecal short-chain fatty acids, and expression levels of genes from exfoliated intestinal cells linked to carcinogenesis.

DISCUSSION

This study will be the first randomized controlled trial to examine the effects of a Mediterranean diet, weight loss, or both on bile acid metabolism, the gut microbiome, and intestinal epithelial genes associated with carcinogenesis. This approach to CRC risk reduction may be especially important among African American/Blacks given their higher risk factor profile and increased CRC incidence.

TRIAL REGISTRATION

ClinicalTrials.gov NCT04753359 . Registered on 15 February 2021.

Interactions between NSAIDs, opioids and the gut microbiota - Future perspectives in the management of inflammation and pain

The composition of intestinal microbiota is influenced by a number of factors, including medications, which may have a substantial impact on host physiology. Nonsteroidal anti-inflammatory drugs (NSAIDs) and opioid analgesics are among those widely used medications that have been shown to alter microbiota composition in both animals and humans. Although much effort has been devoted to identify microbiota signatures associated with these medications, much less is known about the underlying mechanisms. Mucosal inflammation, changes in intestinal motility, luminal pH and bile acid metabolism, or direct drug-induced inhibitory effect on bacterial growth are all potential contributors to NSAID- and opioid-induced dysbiosis, however, only a few studies have addressed directly these issues. In addition, there is a notable overlap between the microbiota signatures of these drugs and certain diseases in which they are used, such as spondyloarthritis (SpA), rheumatoid arthritis (RA) and neuropathic pain associated with type 2 diabetes (T2D). The aims of the present review are threefold. First, we aim to provide a comprehensive up-to-date summary on the bacterial alterations caused by NSAIDs and opioids. Second, we critically review the available data on the possible underlying mechanisms of dysbiosis. Third, we review the current knowledge on gut dysbiosis associated with SpA, RA and neuropathic pain in T2D, and highlight the similarities between them and those caused by NSAIDs and opioids. We posit that drug-induced dysbiosis may contribute to the persistence of these diseases, and may potentially limit the therapeutic effect of these medications by long-term use. In this context, we will review the available literature data on the effect of probiotic supplementation and fecal microbiota transplantation on the therapeutic efficacy of NSAIDs and opioids in these diseases.

Gut microbiota alterations may increase the risk of prescription opioid use, but not vice versa: A two-sample bi-directional Mendelian randomization study

INTRODUCTION

Gut microbiota alterations are strongly associated with prescription opioid use (POU) and multisite chronic pain (MCP). However, whether or not these associations are causal remains unknown. Therefore, we aim to explore the causal relationships between them comprehensively.

METHODS

A two-sample bi-directional Mendelian randomization was conducted to assess the potential associations between gut microbiota and POU/MCP using summary level Genome-wide association studies (GWASs) that were based on predominantly European ancestry.

RESULTS

Potential causal effects were identified between seven host genetic-driven traits of gut microbiota on POU, including Adlercreutzia, Allisonella, Dialister, Anaerofilum, Anaerostipes, ChristensenellaceaeR.7group, and LachnospiraceaeNC2004group at the genus level (p < 0.05) by the Inverse-variance weighted method, with significant causal effects of ChristensenellaceaeR.7group and Allisonella on POU (p < 0.025). A total of five genetically greater abundance of gut microbiota traits were identified to be possibly related to the level of MCP (p < 0.05), including genus ErysipelotrichaceaeUCG003, family Clostridiaceae1, order Gastranaerophilales, order Actinomycetales, and family Actinomycetaceae. In the other direction, no clear evidence was found to support a significant causal relationship between POU and gut microbiota, as well as MCP and gut microbiota. In addition, evidence was also provided for the relationship between triacylglycerols and diacylglycerol elevation, and an increased risk of POU and MCP. No evidence was found across various sensitivity analyses, including reverse causality, pleiotropy, and heterogeneity.

CONCLUSION

The findings from this study provide robust evidence that gut microbiota alterations may be a risk of POU/MCP, but not vice versa.

The effects of microbiota on reproductive health: A review

Reproductive issues are becoming an increasing global problem. There is increasing interest in the relationship between microbiota and reproductive health. Stable microbiota communities exist in the gut, reproductive tract, uterus, testes, and semen. Various effects (e.g., epigenetic modifications, nervous system, metabolism) of dysbiosis in the microbiota can impair gamete quality; interfere with zygote formation, embryo implantation, and embryo development; and increase disease susceptibility, thus adversely impacting reproductive capacity and pregnancy. The maintenance of a healthy microbiota can protect the host from pathogens, increase reproductive potential, and reduce the rates of adverse pregnancy outcomes. In conclusion, this review discusses microbiota in the male and female reproductive systems of multiple animal species. It explores the effects and mechanisms of microbiota on reproduction, factors that influence microbiota composition, and applications of microbiota in reproductive disorder treatment and detection. The findings support novel approaches for managing reproductive diseases through microbiota improvement and monitoring. In addition, it will stimulate further systematic explorations of microbiota-mediated effects on reproduction.

Substance use, microbiome and psychiatric disorders

Accumulating evidence from several studies has shown association between substance use, dysregulation of the microbiome and psychiatric disorders such as depression, anxiety, and psychosis. Many of the abused substances such as cocaine and alcohol have been shown to alter immune signaling pathways and cause inflammation in both the periphery and the central nervous system (CNS). In addition, these substances of abuse also alter the composition and function of the gut microbiome which is known to play important roles such as the synthesis of neurotransmitters and metabolites, that affect the CNS homeostasis and consequent behavioral outcomes. The emerging interactions between substance use, microbiome and CNS neurochemical alterations could contribute to the development of psychiatric disorders. This review provides an overview of the associative effects of substance use such as alcohol, cocaine, methamphetamine, nicotine and opioids on the gut microbiome and psychiatric disorders involving anxiety, depression and psychosis. Understanding the relationship between substance use, microbiome and psychiatric disorders will provide insights for potential therapeutic targets, aimed at mitigating these adverse outcomes.

Long-Term Effects of Developmental Exposure to Oxycodone on Gut Microbiota and Relationship to Adult Behaviors and Metabolism

Opioid drugs are commonly prescribed analgesic to pregnant women. Direct exposure to such drugs may slow gut motility, alter gut permeability, and affect the gut microbiome. While such drugs affect gut microbiome in infants, no study to date has determined whether developmental exposure to such drugs results in longstanding effects on gut microbiota and correspondingly on host responses. We hypothesized developmental exposure to oxycodone (OXY) leads to enduring effects on gut microbiota and such changes are associated with adult neurobehavioral and metabolic changes. Female mice were treated daily with 5 mg OXY/kg or saline solution (control [CTL]) for 2 weeks prior to breeding and then throughout gestation. Male and female offspring pups were weaned, tested with a battery of behavioral and metabolic tests, and fecal boli were collected adulthood (120 days of age). In females, relative abundance of Butyricimonas spp., Bacteroidetes, Anaeroplasma spp., TM7, Enterococcus spp., and Clostridia were greater in OXY versus CTL individuals. In males, relative abundance of Coriobacteriaceae, Roseburia spp., Sutterella spp., and Clostridia were elevated in OXY exposed individuals. Bacterial changes were also associated with predictive metabolite pathway alterations that also varied according to sex. In males and females, affected gut microbiota correlated with metabolic but not behavioral alterations. The findings suggest that developmental exposure to OXY leads to lasting effects on adult gut microbiota that might affect host metabolism, possibly through specific bacterial metabolites or other bacterial-derived products. Further work is needed to characterize how developmental exposure to OXY affects host responses through the gut microbiome.

IMPORTANCE This is the first work to show in a rodent model that in utero exposure to an opioid drug can lead to longstanding effects on the gut microbiota when examined at adulthood. Further, such bacterial changes are associated with metabolic host responses. Given the similarities between rodent and human microbiomes, it raises cause for concern that similar effects may become evident in children born to mothers taking oxycodone and other opioid drugs.

Decreased Intestinal Microbiota Diversity Is Associated With Increased Gastrointestinal Symptoms in Patients With Chronic Pancreatitis

OBJECTIVES

Chronic pancreatitis (CP) is characterized by abdominal pain, recurrent hospitalizations, frequent exposure to antibiotics, nutritional deficiencies, and chronic opioid use. Data describing the gut microbial community structure of patients with CP is limited. We aimed to compare gut microbiota of a group of patients with severe CP being considered for total pancreatectomy with islet autotransplantation (TPIAT) with those of healthy controls and to associate these differences with severity of clinical symptoms.

METHODS

We collected stool from healthy donors (n = 14) and patients with CP (n = 20) undergoing workup for TPIAT, in addition to clinical metadata and a validated abdominal symptoms severity survey.

RESULTS

Patients with CP had significantly lower alpha diversity than healthy controls ( P < 0.001). There was a significantly increased mean relative abundance of Faecalibacterium in healthy controls compared with patients with CP ( P = 0.02). Among participants with CP, those with lower alpha diversity reported worse functional abdominal symptoms ( P = 0.006).

CONCLUSIONS

These findings indicate that changes in gut microbial community structure may contribute to gastrointestinal symptoms and provide basis for future studies on whether enrichment of healthy commensal bacteria such as Faecalibacterium could provide clinically meaningful improvements in outcomes for CP patients undergoing TPIAT.

Interrelations between Gut Microbiota Composition, Nutrient Intake and Diabetes Status in an Adult Japanese Population

Upon food digestion, the gut microbiota plays a pivotal role in energy metabolism, thus affecting the development of type 2 diabetes (DM). We aimed to examine the influence of the composition of selected nutrients consumed on the association between the gut microbiota and DM. This cross-sectional study of a general population was conducted on 1019 Japanese volunteers. Compared with non-diabetic subjects, diabetic subjects had larger proportions of the genera Bifidobacterium and Streptococcus but smaller proportions of the genera Roseburia and Blautia in their gut microbiotas. The genera Streptococcus and Roseburia were positively correlated with the amounts of energy (p = 0.027) and carbohydrate and fiber (p = 0.007 and p = 0.010, respectively) consumed, respectively. In contrast, the genera Bifidobacterium and Blautia were not correlated with any of the selected nutrients consumed. Cluster analyses of these four genera revealed that the Blautia-dominant cluster was most negatively associated with DM, whereas the Bifidobacterium-dominant cluster was positively associated with DM (vs. the Blautia-dominant cluster; odds ratio 3.97, 95% confidence interval 1.68-9.35). These results indicate the possible involvement of nutrient factors in the association between the gut microbiota and DM. Furthermore, independent of nutrient factors, having a Bifidobacterium-dominant gut microbiota may be a risk factor for DM compared to having a Blautia-dominant gut microbiota in a general Japanese population.

Opioid Use, Gut Dysbiosis, Inflammation, and the Nervous System

Opioid use disorder (OUD) is defined as the chronic use or misuse of prescribed or illicitly obtained opioids and is characterized by clinically significant impairment. The etiology of OUD is multifactorial as it is influenced by genetics, environmental factors, stress response and behavior. Given the profound role of the gut microbiome in health and disease states, in recent years there has been a growing interest to explore interactions between the gut microbiome and the central nervous system as a causal link and potential therapeutic source for OUD. This review describes the role of the gut microbiome and opioid-induced immunopathological disturbances at the gut epithelial surface, which collectively contribute to OUD and perpetuate the vicious cycle of addiction and relapse.

Drugs and Bugs: The Gut-Brain Axis and Substance Use Disorders

Substance use disorders (SUDs) represent a significant public health crisis. Worldwide, 5.4% of the global disease burden is attributed to SUDs and alcohol use, and many more use psychoactive substances recreationally. Often associated with comorbidities, SUDs result in changes to both brain function and physiological responses. Mounting evidence calls for a precision approach for the treatment and diagnosis of SUDs, and the gut microbiome is emerging as a contributor to such disorders. Over the last few centuries, modern lifestyles, diets, and medical care have altered the health of the microbes that live in and on our bodies; as we develop, our diets and lifestyle dictate which microbes flourish and which microbes vanish. An increase in antibiotic treatments, with many antibiotic interventions occurring early in life during the microbiome's normal development, transforms developing microbial communities. Links have been made between the microbiome and SUDs, and the microbiome and conditions that are often comorbid with SUDs such as anxiety, depression, pain, and stress. A better understanding of the mechanisms influencing behavioral changes and drug use is critical in developing novel treatments for SUDSs. Targeting the microbiome as a therapeutic and diagnostic tool is a promising avenue of exploration. This review will provide an overview of the role of the gut-brain axis in a wide range of SUDs, discuss host and microbe pathways that mediate changes in the brain's response to drugs, and the microbes and related metabolites that impact behavior and health within the gut-brain axis.

Dose- and Sex-Dependent Bidirectional Relationship between Intravenous Fentanyl Self-Administration and Gut Microbiota

Gut bacteria influence neural circuits in addiction-related behaviors. Given the association between opioid use, gastrointestinal distress, and microbial dysbiosis in humans and mice, we test the hypothesis that interactions between gut bacteria and the brain mediate the rewarding and reinforcing properties of fentanyl. We implant rats with intravenous catheters in preparation for fentanyl intravenous self-administration (IVSA) on an escalating schedule of reinforcement to determine factors that influence fentanyl intake, including sex, dose, and gut microbiota. Our data show the impact of fentanyl IVSA on gut microbiota diversity, as well as the role of gut microbiota on fentanyl IVSA, in Sprague Dawley rats in a sex- and dose-dependent manner (n = 10–16/group). We found that the diversity of gut microbiota within females dose-dependently predicts progressive but not fixed ratio schedules of fentanyl IVSA. Depending on sex and fentanyl dose, alpha diversity (richness and evenness measured with Shannon index) is either increased or decreased following fentanyl IVSA and predicts progressive ratio breakpoint. Our findings collectively suggest a role of gut bacteria in drug-related behavior, including motivation and reinforcement. This work provides feasibility for an intravenous fentanyl self-administration model and uncovers potential factors mediating drug use, which may lead to the development of effective addiction interventions.

Gut-Microbiome Implications in Opioid Use Disorder and Related Behaviors

Substance use disorder (SUD) is a prevalent disease that has caused hundreds of thousands of deaths and affected the lives of even more. Despite its global impact, there is still no known cure for SUD, or the psychological symptoms associated with drug use. Many of the behavioral consequences of drug use prevent people from breaking the cycle of addiction or cause them to relapse back into the cycle due to the physical and psychological consequences of withdrawal. Current research is aimed at understanding the cause of these drug related behaviors and therapeutically targeting them as a mechanism to break the addiction cycle. Research on opioids suggests that the changes in the microbiome during drug use modulated drug related behaviors and preventing these microbial changes could attenuate behavioral symptoms. This review aims to highlight the relationship between the changes in the microbiome and behavior during opioid treatment, as well as highlight the additional research needed to understand the mechanism in which the microbiome modulates behavior to determine the best therapeutic course of action.

Intestinal AMPK modulation of microbiota mediates crosstalk with brown fat to control thermogenesis

The energy-dissipating capacity of brown adipose tissue through thermogenesis can be targeted to improve energy balance. Mammalian 5'-AMP-activated protein kinase, a key nutrient sensor for maintaining cellular energy status, is a known therapeutic target in Type II diabetes. Despite its well-established roles in regulating glucose metabolism in various tissues, the functions of AMPK in the intestine remain largely unexplored. Here we show that AMPKα1 deficiency in the intestine results in weight gain and impaired glucose tolerance under high fat diet feeding, while metformin administration fails to ameliorate these metabolic disorders in intestinal AMPKα1 knockout mice. Further, AMPKα1 in the intestine communicates with brown adipose tissue to promote thermogenesis. Mechanistically, we uncover a link between intestinal AMPKα1 activation and BAT thermogenic regulation through modulating anti-microbial peptide-controlled gut microbiota and the metabolites. Our findings identify AMPKα1-mediated mechanisms of intestine-BAT communication that may partially underlie the therapeutic effects of metformin.

Immunoregulatory Intestinal Microbiota and COVID-19 in Patients with Type Two Diabetes: A Double-Edged Sword

Coronavirus disease 2019, or COVID-19, is a major challenge facing scientists worldwide. Alongside the lungs, the system of organs comprising the GI tract is commonly targeted by COVID-19. The dysbiotic modulations in the intestine influence the disease severity, potentially due to the ability of the intestinal microbiota to modulate T lymphocyte functions, i.e., to suppress or activate T cell subpopulations. The interplay between the lungs and intestinal microbiota is named the gut-lung axis. One of the most usual comorbidities in COVID-19 patients is type 2 diabetes, which induces changes in intestinal microbiota, resulting in a pro-inflammatory immune response, and consequently, a more severe course of COVID-19. However, changes in the microbiota in this comorbid pathology remain unclear. Metformin is used as a medication to treat type 2 diabetes. The use of the type 2 diabetes drug metformin is a promising treatment for this comorbidity because, in addition to its hypoglycemic action, it can increase amount of intestinal bacteria that induce regulatory T cell response. This dual activity of metformin can reduce lung damage and improve the course of the COVID-19 disease.

Gut microbiota in patients with obesity and metabolic disorders - a systematic review

BACKGROUND

Previous observational studies have demonstrated inconsistent and inconclusive results of changes in the intestinal microbiota in patients with obesity and metabolic disorders. We performed a systematic review to explore evidence for this association across different geography and populations.

METHODS

We performed a systematic search of MEDLINE (OvidSP) and Embase (OvidSP) of articles published from Sept 1, 2010, to July 10, 2021, for case-control studies comparing intestinal microbiome of individuals with obesity and metabolic disorders with the microbiome of non-obese, metabolically healthy individuals (controls). The primary outcome was bacterial taxonomic changes in patients with obesity and metabolic disorders as compared to controls. Taxa were defined as "lean-associated" if they were depleted in patients with obesity and metabolic disorders or negatively associated with abnormal metabolic parameters. Taxa were defined as "obesity-associated" if they were enriched in patients with obesity and metabolic disorders or positively associated with abnormal metabolic parameters.

RESULTS

Among 2390 reports screened, we identified 110 full-text articles and 60 studies were included. Proteobacteria was the most consistently reported obesity-associated phylum. Thirteen, nine, and ten studies, respectively, reported Faecalibacterium, Akkermansia, and Alistipes as lean-associated genera. Prevotella and Ruminococcus were obesity-associated genera in studies from the West but lean-associated in the East. Roseburia and Bifidobacterium were lean-associated genera only in the East, whereas Lactobacillus was an obesity-associated genus in the West.

CONCLUSIONS

We identified specific bacteria associated with obesity and metabolic disorders in western and eastern populations. Mechanistic studies are required to determine whether these microbes are a cause or product of obesity and metabolic disorders.

Health improvements of type 2 diabetic patients through diet and diet plus fecal microbiota transplantation

Type 2 diabetes (T2D) is a major public health problem, and gut microbiota dysbiosis has been implicated in the emergence of T2D in humans. Dietary interventions can indirectly influence the health status of patients with type 2 diabetes through their modulatory effects on the intestinal microbiota. In recent years, fecal microbiota transplantation is becoming familiar as a new medical treatment that can rapidly improve intestinal health. We conducted a 90-day controlled open-label trial to evaluate the health improvement ability of a specially designed diet, and the diet combined with fecal microbiota transplantation (FMT). According to our study, both diet and diet plus FMT treatments showed great potential in controlling blood glucose and blood pressure levels. Sequencing the V4 region of 16S rRNA gene on the Illumina MiniSeq platform revealed a shift of intestinal microbial community in T2D patients, and the changes were also observed in response to the treatments. FMT changed the gut microbiota more quickly than diet. Beneficial bacterium, such as Bifidobacterium, increased along the study and was negatively correlated with blood glucose, blood pressure, blood lipid and BMI. Sulfate-reducing bacteria (SRB), Bilophila and Desulfovibrio, decreased significantly after treatment, showed a positive correlation with blood glucose indices. Thus, the specially designed diet is beneficial to improve blood glucose control in diabetic patients, it also showed the potential to reverse dyslipidemia and dysarteriotony.

An altered microbiota pattern precedes Type 2 diabetes mellitus development: From the CORDIOPREV study

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Type 2 diabetes (T2DM) increases the risk of recurrence in myocardial infarction patients.

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A gut microbiota profile is associated to the further T2DM development.

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Microbiome data improved the prediction of T2DM development when added to clinical parameters.

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A risk score including the most predictive genera was associated with the probability of T2DM.

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A high risk score was associated with a higher hepatic insulin resistance and β-cell dysfunction.

Introduction

A distinctive gut microbiome have been linked to type 2 diabetes mellitus (T2DM).

Objectives

We aimed to evaluate whether gut microbiota composition, in addition to clinical biomarkers, could improve the prediction of new incident cases of diabetes in patients with coronary heart disease.

Methods

All the patients from the CORDIOPREV (Clinical Trials.gov.Identifier: NCT00924937) study without T2DM at baseline were included (n = 462). Overall, 107 patients developed it after a median of 60 months. The gut microbiota composition was determined by 16S rRNA gene sequencing and predictive models were created using hold-out method.

Results

A gut microbiota profile associated with T2DM development was determined through a microbiome-based predictive model. The addition of microbiome data to clinical parameters (variables included in FINDRISC risk score and the diabetes risk score of the American Diabetes Association, HDL, triglycerides and HbA1c) improved the prediction increasing the area under the curve from 0.632 to 0.946. Furthermore, a microbiome-based risk score including the ten most discriminant genera, was associated with the probability of develop T2DM.

Conclusion

These results suggest that a microbiota profile is associated to the T2DM development. An integrate predictive model of microbiome and clinical data that can improve the prediction of T2DM is also proposed, if is validated in independent populations to prevent this disease.

Potential roles of the gut microbiota in the manifestations of drug use disorders

Drug use disorders (DUDs) not only cause serious harm to users but also cause huge economic, security, and public health burdens to families and society. Recently, several studies have shown that gut microbiota (GM) can affect the central nervous system and brain functions. In this review, we focus on the potential role of the GM in the different stages of DUDs. First, the GM may induce individuals to seek novel substances. Second, the gut microbiota is involved in the decomposition and absorption of drugs. Symptoms of individuals who suffer from DUDs are also related to intestinal microorganisms. Third, the effects of the GM and its metabolites on drug relapse are mainly reflected in the reward effect and drug memory. In conclusion, recent studies have preliminarily explored the relationship between GM and DUDs. This review deepens our understanding of the mechanisms of DUDs and provides important information for the future development of clinical treatment for DUDs.

DYNAMICS OF CHANGES IN THE MICROBIAL PICTURE OF THE ORAL CAVITY ON THE BACKGROUND OF CHRONIC OPIOID EXPOSURE IN THE EXPERIMENT

OBJECTIVE

The aim is to investigate changes in the microbiota of dental biofilm at the end of the eighth, tenth and twelfth weeks of experimental opioid exposure.

PATIENTS AND METHODS

Materials and methods: The study was performed on 36 white outbred adult male rats, which were injected with the opioid analgesic nalbuphine in increasing doses (0,212 - 0,3 mg / kg) during 8, 10 and 12 weeks. Qualitative and quantitative composition of microbiota of dental biofilm was studied using statistical analysis.

RESULTS

Results: After eight weeks of opioid exposure, changes in microbiocenosis of dental biofilm of rats were caused by a significant increase in saprophytic and opportunistic microbiota and an appearance of pathogenic species of indicator microbiota with potential periodontopathogenic action. At the end of the tenth week, a significant increase in the quantitative indicators of certain species of opportunistic microbiota and increase in the quantitative composition of pathogenic bacteria were determined. After twelve week of opioid exposure, a significant increase in the quantitative indicators of pathogenic microbiota of dental biofilm was detected.

CONCLUSION

Conclusions: Changes in the qualitative and quantitative composition of the microbiocenosis of the dental biofilm at the end of 8, 10 and 12 weeks of opioid exposure were established, they were manifested by a significant increase in the quantitative indicators of certain species of opportunistic microorganisms and a significant increase in pathogenic microbiota in the dynamics, which led to the progression of dysbiotic changes and purulent-inflammatory process in the oral cavity of rats.

The Effects of Probiotic Supplementation on Opioid-Related Disorder in Patients under Methadone Maintenance Treatment Programs

INTRODUCTION

Patients under methadone maintenance treatment programs (MMTPs) are susceptible to numerous complications (e.g., mental and metabolic disorders). This study evaluated the effects of probiotics on clinical symptoms, biomarkers of oxidative stress, inflammation, insulin resistance, and serum lipid content in patients receiving MMTPs.

MATERIALS AND METHODS

A randomized, double-blind, placebo-controlled trial was conducted among 70 patients receiving MMTPs to receive either 1.8 × 10⁹ CFU/day probiotics (n = 35) or placebo (n = 35) for 12 weeks. Clinical symptoms and metabolic profiles were measured before and after the intervention in patients receiving MMTPs.

RESULTS

Compared with the placebo group, probiotic supplementation resulted in a significant improvement in the severity of depression (P < 0.05). In addition, probiotic administration significantly decreased fasting plasma glucose (FPG), total cholesterol, and low-density lipoprotein cholesterol (LDL cholesterol) (P < 0.05). Furthermore, probiotics resulted in a significant reduction in high-sensitivity C-reactive protein (hs-CRP) and a significant elevation in total antioxidant capacity (TAC) and total glutathione (GSH) levels (P < 0.05).

CONCLUSION

Treatment with probiotics for 12 weeks to patients receiving MMTPs had beneficial effects on symptoms of depression, as well as several metabolic profiles. Clinical Trial Registration: this study was registered in the Iranian website (https://www.irct.ir) for clinical trials registration (https://fa.irct.ir/trial/46363/IRCT20170420033551N9). The registration date is March 22, 2020.

Morphine mediated neutrophil infiltration in intestinal tissue play essential role in histological damage and microbial dysbiosis

The gut microbial ecosystem exhibits a complex bidirectional communication with the host and is one of the key contributing factors in determining mucosal immune homeostasis or an inflammatory state. Opioid use has been established to induce gut microbial dysbiosis consistent with increased intestinal tissue inflammation. In this study, we investigated the role of infiltrated immune cells in morphine-induced intestinal tissue damage and gut microbial dysbiosis in mice. Results reveal a significant increase in chemokine expression in intestinal tissues followed by increased neutrophil infiltration post morphine treatment which is direct consequence of a dysbiotic microbiome since the effect is attenuated in antibiotics treated animals and in germ-free mice. Neutrophil neutralization using anti-Ly6G monoclonal antibody showed a significant decrease in tissue damage and an increase in tight junction protein organization. 16S rRNA sequencing on intestinal samples highlighted the role of infiltrated neutrophils in modulating microbial community structure by providing a growth benefit for pathogenic bacteria, such as Enterococcus, and simultaneously causing a significant depletion of commensal bacteria, such as Lactobacillus. Taken together, we provide the first direct evidence that neutrophil infiltration contributes to morphine-induced intestinal tissue damage and gut microbial dysbiosis. Our findings implicate that inhibition of neutrophil infiltration may provide therapeutic benefits against gastrointestinal dysfunctions associated with opioid use.

Effects of Oral Glucose-Lowering Agents on Gut Microbiota and Microbial Metabolites

The current research and existing facts indicate that type 2 diabetes mellitus (T2DM) is characterized by gut microbiota dysbiosis and disturbed microbial metabolites. Oral glucose-lowering drugs are reported with pleiotropic beneficial effects, including not only a decrease in glucose level but also weight loss, antihypertension, anti-inflammation, and cardiovascular protection, but the underlying mechanisms are still not clear. Evidence can be found showing that oral glucose-lowering drugs might modify the gut microbiome and thereby alter gastrointestinal metabolites to improve host health. Although the connections among gut microbial communities, microbial metabolites, and T2DM are complex, figuring out how antidiabetic agents shape the gut microbiome is vital for optimizing the treatment, meaningful for the instruction for probiotic therapy and gut microbiota transplantation in T2DM. In this review, we focused on the literatures in gut microbiota and its metabolite profile alterations beneficial from oral antidiabetic drugs, trying to provide implications for future study in the developing field of these drugs, such as combination therapies, pre- and probiotics intervention in T2DM, and subjects with pregestational diabetes and gestational diabetes mellitus.

Circulating Nucleic Acid-Based Biomarkers of Type 2 Diabetes

Type 2 diabetes (T2D) is a deficiency in how the body regulates glucose. Uncontrolled T2D will result in chronic high blood sugar levels, eventually resulting in T2D complications. These complications, such as kidney, eye, and nerve damage, are even harder to treat. Identifying individuals at high risk of developing T2D and its complications is essential for early prevention and treatment. Numerous studies have been done to identify biomarkers for T2D diagnosis and prognosis. This review focuses on recent T2D biomarker studies based on circulating nucleic acids using different omics technologies: genomics, transcriptomics, and epigenomics. Omics studies have profiled biomarker candidates from blood, urine, and other non-invasive samples. Despite methodological differences, several candidate biomarkers were reported for the risk and diagnosis of T2D, the prognosis of T2D complications, and pharmacodynamics of T2D treatments. Future studies should be done to validate the findings in larger samples and blood-based biomarkers in non-invasive samples to support the realization of precision medicine for T2D.

Chronic opioid use modulates human enteric microbiota and intestinal barrier integrity

Over the past three decades the United States has experienced a devastating opioid epidemic. One of the many debilitating side effects of chronic opioid use is opioid-induced bowel dysfunction. We investigated the impact of methadone maintenance treatment (MMT) on the gut microbiome, the gut bacterial metabolite profile, and intestinal barrier integrity. An imbalance in key bacterial communities required for production of short-chain fatty acids (SCFAs), mucus degradation, and maintenance of barrier integrity was identified. Consistent with dysbiosis, levels of fecal SCFAs were reduced in MMT. We demonstrated that metabolites synthesized by Akkermansia muciniphila modulate intestinal barrier integrity in vitro by strengthening the pore pathway and regulating tight junction protein expression. This study provides essential information about the therapeutic potential of A. muciniphila and warrants development of new clinical strategies that aim to normalize the gut microbiome in individuals affected by chronic opioid use.

Gut microbiota in a population highly affected by obesity and type 2 diabetes and susceptibility to COVID-19

Coronavirus disease 2019 (COVID-19) is a disease produced by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and it is currently causing a catastrophic pandemic affecting humans worldwide. This disease has been lethal for approximately 3.12 million people around the world since January 2020. Globally, among the most affected countries, Mexico ranks third in deaths after the United States of America and Brazil. Although the high number of deceased people might also be explained by social aspects and lifestyle customs in Mexico, there is a relationship between this high proportion of deaths and comorbidities such as high blood pressure (HBP), type 2 diabetes, obesity, and metabolic syndrome. The official epidemiological figures reported by the Mexican government have indicated that 18.4% of the population suffers from HBP, close to 10.3% of adults suffer from type 2 diabetes, and approximately 36.1% of the population suffers from obesity. Disbalances in the gut microbiota (GM) have been associated with these diseases and with COVID-19 severity, presumably due to inflammatory dysfunction. Recent data about the association between GM dysbiosis and metabolic diseases could suggest that the high levels of susceptibility to SARS-CoV-2 infection and COVID-19 morbidity in the Mexican population are primarily due to the prevalence of type 2 diabetes, obesity, and metabolic syndrome.

The Microbiome-Gut-Brain Axis, a Potential Therapeutic Target for Substance-Related Disorders

Substance addiction is a complex worldwide public health problem. It endangers both personal life and social stability, causing great loss on economy. Substance-related disorder is considered to be a complicated chronic brain disorder. It resulted from interactions among pharmacological properties of addictive substances, individual susceptibility, and social–environmental factors. Unfortunately, there is still no ideal treatment for this disorder. Recent lines of evidence suggest that gut microbiome may play an important role in the pathogenesis of neuropsychiatric disorders, including substance-related disorders. This review summarizes the research on the relationship between gut microbiome and substance-related disorders, including different types of substance, different individual susceptibility, and the occurrence and development of substance-induced mental disorders. We also discuss the potentiation of gut microbiome in the treatment of substance-related disorders, especially in the treatment of substance-induced mental disorders and manipulation on individuals’ responsiveness to addictive substances.

The Guts of the Opioid Crisis

Bidirectional interactions of the gut epithelium with commensal bacteria are critical for maintaining homeostasis within the gut. Chronic opioid exposure perturbs gut homeostasis through a multitude of neuro-immune-epithelial mechanisms, resulting in the development of analgesic tolerance, a major underpinning of the current opioid crisis. Differences in molecular mechanisms of opioid tolerance between the enteric and central pain pathways pose a significant challenge for managing chronic pain without untoward gastrointestinal effects.

Role of microbes in the pathogenesis of neuropsychiatric disorders

Microbes inhabit different anatomical sites of the human body including oral cavity, gut, and skin. A growing literature highlights how microbiome variation is associated with human health and disease. There is strong evidence of bidirectional communication between gut and brain mediated by neurotransmitters and microbial metabolites. Here, we review the potential involvement of microbes residing in the gut and in other body sites in the pathogenesis of eight neuropsychiatric disorders, discussing findings from animal and human studies. The data reported provide a comprehensive overview of the current state of the microbiome research in neuropsychiatry, including hypotheses about the mechanisms underlying the associations reported and the translational potential of probiotics and prebiotics.

Endogenous opiates and behavior: 2019

This paper is the forty-second consecutive installment of the annual anthological review of research concerning the endogenous opioid system, summarizing articles published during 2019 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides and receptors as well as effects of opioid/opiate agonists and antagonists. The review is subdivided into the following specific topics: molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors (1), the roles of these opioid peptides and receptors in pain and analgesia in animals (2) and humans (3), opioid-sensitive and opioid-insensitive effects of nonopioid analgesics (4), opioid peptide and receptor involvement in tolerance and dependence (5), stress and social status (6), learning and memory (7), eating and drinking (8), drug abuse and alcohol (9), sexual activity and hormones, pregnancy, development and endocrinology (10), mental illness and mood (11), seizures and neurologic disorders (12), electrical-related activity and neurophysiology (13), general activity and locomotion (14), gastrointestinal, renal and hepatic functions (15), cardiovascular responses (16), respiration and thermoregulation (17), and immunological responses (18).

Fecal microbiota transplantation and antibiotic treatment attenuate naloxone-precipitated opioid withdrawal in morphine-dependent mice

Opioid addiction can produce severe side effects including physical dependence and withdrawal. Perturbations of the gut microbiome have recently been shown to alter opioid-induced side-effects such as addiction, tolerance and dependence. In the present study, we investigated the influence of the gut microbiome on opioid withdrawal by evaluating the effects of fecal microbiota transplantation (FMT), antibiotic and probiotic treatments, and pharmacological inhibition of gut permeability in a mouse model of opioid dependence. Repeated intraperitoneal (i.p.) morphine treatment produced physical dependence that was quantified by measuring somatic signs of withdrawal (i.e. number of jumps) precipitated using the opioid antagonist naloxone. Morphine-dependent mice that received FMT from morphine-treated donor mice exhibited fewer naloxone-precipitated jumps compared to morphine-dependent counterparts receiving FMT from saline-treated donor mice. Microbial contents in the mouse cecum were altered by morphine treatment but were not differentially impacted by FMT. A broad-spectrum antibiotic cocktail (ABX) regimen reduced the bacterial load and attenuated naloxone-precipitated morphine withdrawal in morphine-dependent mice, whereas commercially available probiotic strains did not reliably alter somatic signs of opioid withdrawal. ML-7, a pharmacological inhibitor of gut permeability, reduced the morphine-induced increase in gut permeability in vivo but did not reliably alter somatic signs of naloxone-precipitated opioid withdrawal. Our results suggest that the gut microbiome impacts the development of physical dependence induced by chronic morphine administration, and that therapeutic manipulations of the gut microbiome may reduce opioid withdrawal.

Blood-Glucose-Lowering Effect of Coptidis Rhizoma Extracts From Different Origins via Gut Microbiota Modulation in db/db Mice

Background:Coptidis rhizoma extracts (CREs) have been used widely for their anti-diabetic and anti-microbial activities, and berberine/jatrorrhizine/coptisine/palmatine are the primary bioactive components. Although guidelines have adopted content analyses of these components as a quality control method for CREs, it is difficult to differentiate the CREs from different sources using this method because of the lack of indications for their related pharmacological activities.

Purpose: To explore the effect of CREs (CREA/CREB/CREC) with different compositions of major components on the gut microbiota and blood glucose levels in db/db mice.

Methods: Degradation of berberine/jatrorrhizine/coptisine/palmatine from CREA/CREB/CREC in rat/mouse intestinal contents and their impact on nine common gastrointestinal bacteria were investigated. In addition, the effects of oral administration of CREA/CREB/CREC for 2 weeks on the gut microbiota and blood glucose levels in db/db mice were monitored via insulin/glucose tolerance test (ITT/GTT), insulin concentration, homeostatic model assessment of insulin resistance and fecal 16S rRNA sequencing.

Results and Conclusion: The total amount of berberine/jatrorrhizine/coptisine/palmatine was highest in CREA. Clostridium perfringens was strongly inhibited by all three CREs, with CREA demonstrating the most significant inhibitory effects on minimum inhibitory concentration, time-kill kinetics, and ATP production. In db/db mice, CREA resulted in the most significant decrease in ITT/GTT and depicted different changes in the microbiota from CREB/CREC. Thus, CREs with different compositions of berberine/jatrorrhizine/coptisine/palmatine differed in terms of time-kill kinetics and ATP production assays on C. perfringens. CREA revealed the potent bacterial inhibitory effects and glucose-lowering activity.

Association of diabetes and microbiota: An update

Diabetes is an emerging health condition globally and is suggested to have a direct connection with the gut microbiota that determine our metabolic outcomes. Sensitivity to insulin and glucose metabolism is normal in healthy people as compared to those people who cannot maintain their glucose metabolism. One of the reasons of the differences is that healthy people have different microbiome that leads to achieve more short chain fatty acids and make up more branched amino acids, while the gut microbiota of the other group of people are more likely to produce compounds that affects glucose metabolism. Herein, this review will present the research related to the impact of gut microbes on diabetes carried out in the past decade. The review focus on the relation between gut microbiota and Type-1 Diabetes (T1D), Type-2 Diabetes (T2D), and how gut microbiota could be an alternative therapy for treatment of diabetes.