12,13-diHOME and noradrenaline are associated with the occurrence of acute myocardial infarction in patients with type 2 diabetes mellitus.

BACKGROUND: Acute myocardial infarction (AMI) is the most prevalent cause of mortality and morbidity in patients with type 2 diabetes mellitus (T2DM). However, strict blood glucose control does not always prevent the development and progression of AMI. Therefore, the present study aimed to explore potential new biomarkers associated with the occurrence of AMI in T2DM patients. METHODS: A total of 82 participants were recruited, including the control group (n = 28), T2DM without AMI group (T2DM, n = 30) and T2DM with initial AMI group (T2DM + AMI, n = 24). The untargeted metabolomics using liquid chromatography-mass spectrometry (LC-MS) analysis was performed to evaluate the changes in serum metabolites. Then, candidate metabolites were determined using ELISA method in the validation study (n = 126/T2DM group, n = 122/T2DM + AMI group). RESULTS: The results showed that 146 differential serum metabolites were identified among the control, T2DM and T2DM + AMI, Moreover, 16 differentially-expressed metabolites were significantly altered in T2DM + AMI compared to T2DM. Amino acid and lipid pathways were the major involved pathways. Furthermore, three candidate differential metabolites, 12,13-dihydroxy-9Z-octadecenoic acid (12,13-diHOME), noradrenaline (NE) and estrone sulfate (ES), were selected for validation study. Serum levels of 12,13-diHOME and NE in T2DM + AMI were significantly higher than those in T2DM. Multivariate logistic analyses showed that 12,13-diHOME (OR, 1.491; 95% CI 1.230-1.807, P < 0.001) and NE (OR, 8.636; 95% CI 2.303-32.392, P = 0.001) were independent risk factors for AMI occurrence in T2T2DM patients. The area under receiver operating characteristic (ROC) curve (AUC) were 0.757 (95% CI 0.697-0.817, P < 0.001) and 0.711(95% CI 0.648-0.775, P < 0.001), respectively. The combination of both significantly improved the AUC to 0.816 (95% CI 0.763-0.869, P < 0.001). CONCLUSIONS: 12,13-diHOME and NE may lead to understanding the possible metabolic alterations associated with AMI onset in T2DM population and serve as promising risk factors and therapeutic targets.

Patients with breath test positive are necessary to be identified from irritable bowel syndrome: a clinical trial based on microbiomics and rifaximin sensitivity.

BACKGROUND: As a non-invasive and effective diagnostic method for small intestinal bacterial overgrowth (SIBO), wild-use of breath test (BT) has demonstrated a high comorbidity rate in patients with diarrhea-predominant irritable bowel syndrome (IBS-D) and SIBO. Patients overlapping with SIBO respond better to rifaximin therapy than those with IBS-D only. Gut microbiota plays a critical role in both of these two diseases. We aimed to determine the microbial difference between IBS-D overlapping with/without SIBO, and to study the underlying mechanism of its sensitivity to rifaximin. METHODS: Patients with IBS-D were categorized as BT-negative (IBSN) and BT-positive (IBSP). Healthy volunteers (BT-negative) were enrolled as healthy control. The patients were clinically evaluated before and after rifaximin treatment (0.4 g bid, 4 weeks). Blood, intestine, and stool samples were collected for cytokine assessment and gut microbial analyses. RESULTS: Clinical complaints and microbial abundance were significantly higher in IBSP than in IBSN. In contrast, severe systemic inflammation and more active bacterial invasion function that were associated with enrichment of opportunistic pathogens were seen in IBSN. The symptoms of IBSP patients were relieved in different degrees after therapy, but the symptoms of IBSN rarely changed. We also found that the presence of IBSN-enriched genera ( Enterobacter and Enterococcus ) are unaffected by rifaximin therapy. CONCLUSIONS: IBS-D patients overlapping with SIBO showed noticeably different fecal microbial composition and function compared with IBS-D only. The better response to rifaximin in those comorbid patients might associate with their different gut microbiota, which suggests that BT is necessary before IBS-D diagnosis and use of rifaximin. REGISTRATION: Chinese Clinical Trial Registry, ChiCTR1800017911.

Roseburia hominis Alleviates Neuroinflammation via Short-Chain Fatty Acids through Histone Deacetylase Inhibition.

SCOPE: The gut microbiota plays a prominent role in gut-brain interactions and gut dysbiosis is involved in neuroinflammation. However, specific probiotics targeting neuroinflammation need to be explored. In this study, the antineuroinflammatory effect of the potential probiotic Roseburia hominis (R. hominis) and its underlying mechanisms is investigated. METHODS AND RESULTS: First, germ-free (GF) rats are orally treated with R. hominis. Microglial activation, proinflammatory cytokines, levels of short-chain fatty acids, depressive behaviors, and visceral sensitivity are assessed. Second, GF rats are treated with propionate or butyrate, and microglial activation, proinflammatory cytokines, histone deacetylase 1 (HDAC1), and histone H3 acetyl K9 (Ac-H3K9) are analyzed. The results show that R. hominis administration inhibits microglial activation, reduces the levels of IL-1α, INF-γ, and MCP-1 in the brain, and alleviates depressive behaviors and visceral hypersensitivity in GF rats. Moreover, the serum levels of propionate and butyrate are increased significantly in the R. hominis-treated group. Propionate or butyrate treatment reduces microglial activation, the levels of proinflammatory cytokines and HDAC1, and promotes the expression of Ac-H3K9 in the brain. CONCLUSION: These findings suggest that R. hominis alleviates neuroinflammation by producing propionate and butyrate, which serve as HDAC inhibitors. This study provides a potential psychoprobiotic to reduce neuroinflammation.

Stomatal conductance of tomato leaves is regulated by both abscisic acid and leaf water potential under combined water and salt stress.

Stomatal conductance (gs ) affects water use efficiency (WUE) through coordinating photosynthesis and transpiration and is regulated by chemical and/or hydraulic signals. However, the regulation mechanism of gs of tomato leaves has not been fully explored under combined water and salt stress. Here, we set up four salt treatments and two water treatments in a climate greenhouse and measured stomatal morphologies and conductance and other photosynthesis parameters. Water and salt stress reduced stomatal length (SL), width, perimeter, area (amax ), density (SD), and the maximum stomatal conductance (gsmax ). Water and salt stress had a separate weakening effect on net photosynthetic rate (A) and transpiration rate but interactively reduced gs . The contents of abscisic acid (ABA) and Na+ in tomato leaves increased with the NaCl concentration, while leaf water potential (Ψl ) and chlorophyll content decreased. Under full irrigation, gsmax was coordinated by SD and amax , and gs by ABA content under salt stress. Under water and salt combined stress, gsmax was affected by amax , and gs was coordinated with ABA and Ψl . The decrease of A was caused by both a reduction of chlorophyll content and gs under water and salt stress. Intrinsic WUE did not reduce under full irrigation or mild to moderate salt stress but decreased under a combination of water and severe salt stress, indicating that the leaves of the tested tomato cultivar performed better under moderate salt stress. Collectively, these results can provide useful insights for the efficient management of water and salt to adapt to drought and high salt environments.

Berberine alleviates visceral hypersensitivity in rats by altering gut microbiome and suppressing spinal microglial activation.

Accumulating evidence shows that agents targeting gut dysbiosis are effective for improving symptoms of irritable bowel syndrome (IBS). However, the potential mechanisms remain unclear. In this study we investigated the effects of berberine on the microbiota-gut-brain axis in two rat models of visceral hypersensitivity, i.e., specific pathogen-free SD rats subjected to chronic water avoidance stress (WAS) and treated with berberine (200 mg· kg-1 ·d-1, ig, for 10 days) as well as germ-free (GF) rats subjected to fecal microbiota transplantation (FMT) from a patient with IBS (designated IBS-FMT) and treated with berberine (200 mg· kg-1 ·d-1, ig, for 2 weeks). Before the rats were sacrificed, visceral sensation and depressive behaviors were evaluated. Then colonic tryptase was measured and microglial activation in the dorsal lumbar spinal cord was assessed. The fecal microbiota was profiled using 16S rRNA sequencing, and short chain fatty acids (SCFAs) were measured. We showed that berberine treatment significantly alleviated chronic WAS-induced visceral hypersensitivity and activation of colonic mast cells and microglia in the dorsal lumbar spinal cord. Transfer of fecal samples from berberine-treated stressed donors to GF rats protected against acute WAS. FMT from a patient with IBS induced visceral hypersensitivity and pro-inflammatory phenotype in microglia, while berberine treatment reversed the microglial activation and altered microbial composition and function and SCFA profiles in stools of IBS-FMT rats. We demonstrated that berberine did not directly influence LPS-induced microglial activation in vitro. In both models, several SCFA-producing genera were enriched by berberine treatment, and positively correlated to the morphological parameters of microglia. In conclusion, activation of microglia in the dorsal lumbar spinal cord was involved in the pathogenesis of IBS caused by dysregulation of the microbiota-gut-brain axis, and the berberine-altered gut microbiome mediated the modulatory effects of the agent on microglial activation and visceral hypersensitivity, providing a potential option for the treatment of IBS.

Berberine ameliorates ovariectomy-induced anxiety-like behaviors by enrichment in equol generating gut microbiota.

The gut microbiota is recognized as a promising therapeutic target for anxiety. Berberine (BBR) has shown efficacy in the treatment of diseases such as postmenopausal osteoporosis, obesity, and type 2 diabetes through regulating the gut microbiota. However, the effects of BBR on postmenopausal anxiety are still unclear. The purpose of the study is to test whether BBR ameliorates anxiety by modulating intestinal microbiota under estrogen-deficient conditions. Experimental anxiety was established in specific pathogen-free (SPF) ovariectomized (OVX) rats, which were then treated with BBR for 4 weeks before undergoing behavioral tests. Open field and elevated plus maze tests demonstrated that BBR treatment significantly ameliorated anxiety-like behaviors of OVX rats compared with vehicle-treated counterparts. Moreover, as demonstrated by 16S rRNA sequencing and liquid chromatography/mass spectrometry (LC/MS) analysis, BBR-treated OVX rats harbored a higher abundance of beneficial gut microbes, such as Bacteroides, Bifidobacterium, Lactobacillus, and Akkermansia, and exhibited increased equol generation. Notably, gavage feeding of BBR had no significant anti-anxiety effects on germ-free (GF) rats that underwent ovariectomy, whereas GF rats transplanted with fecal microbiota from SPF rats substantially phenocopied the donor rats in terms of anxiety-like symptoms and isoflavone levels. This study indicates that the gut microbiota is critical in the treatment of ovariectomy-aggravated anxiety, and that BBR modulation of the gut microbiota is a promising therapeutic strategy for treating postmenopausal symptoms of anxiety.

Roseburia hominis Increases Intestinal Melatonin Level by Activating p-CREB-AANAT Pathway.

Intestinal melatonin exerts diverse biological effects on the body. Our previous research showed that the abundance of the butyrate-producing bacteria, Roseburia, is positively related to the expression of colonic mucosal melatonin. However, the detailed relationship is unclear. Therefore, we aimed to explore whether Roseburia regulates intestinal melatonin and its underlying mechanisms. Male Sprague-Dawley germfree rats were orally administered with or without Roseburia hominis. R. hominis treatment significantly increased the intestinal melatonin level. The concentrations of propionate and butyrate in the intestinal contents were significantly elevated after gavage of R. hominis. Propionate or butyrate treatment increased melatonin, 5-hydroxytryptamine (5-HT), arylalkylamine N-acetyltransferase (AANAT), and phosphorylated cAMP-response element-binding protein (p-CREB) levels. When pretreated with telotristat ethyl, the inhibitor of tryptophan hydroxylase (TPH), or siRNA of Aanat, or 666-15, i.e., an inhibitor of CREB, propionate, or butyrate, could not promote melatonin production in the pheochromocytoma cell line BON-1. Metabolomics analysis showed that propionate and butyrate stimulation regulated levels of some metabolites and some metabolic pathways in BON-1 cell supernatants. In conclusion, propionate and butyrate, i.e., metabolites of R. hominis, can promote intestinal melatonin synthesis by increasing 5-HT levels and promoting p-CREB-mediated Aanat transcription, thereby offering a potential target for ameliorating intestinal diseases.

Fusobacterium nucleatum Causes Microbial Dysbiosis and Exacerbates Visceral Hypersensitivity in a Colonization-Independent Manner.

Background: Microbial dysbiosis is closely associated with visceral hypersensitivity and is involved in the pathogenesis of irritable bowel syndrome (IBS), but the specific strains that play a key role have yet to be identified. Previous bioinformatic studies have demonstrated that Fusobacterium is a shared microbial feature between IBS patients and maternal separation (MS)-stressed rats. In this study, we assessed the potential role of Fusobacterium nucleatum (F. nucleatum) in the pathogenesis of IBS. Methods: Fecal samples of patients with diarrhea predominant-IBS (IBS-D) and healthy controls were obtained. An MS rat model was established to receive gavage of either F. nucleatum or normal saline. Visceral sensitivity was evaluated through colorectal distension test, and fecal microbiota was analyzed by 16S rRNA gene sequencing. F. nucleatum-specific IgA levels in fecal supernatants were assessed by western blotting. The antigen reacted with the specific IgA of F. nucleatum was identified by mass spectrometry and the construction of a recombinant Escherichia coli BL21 (DE3). Results: IBS-D patients showed a lower Shannon index and a higher abundance of Fusobacterium. The F. nucleatum-gavage was shown to exacerbate visceral hypersensitivity in MS rats, with both the F. nucleatum-gavage and MS causing a decreased Shannon index and a clear segregation of fecal microbiota. In addition, specific IgA against F. nucleatum was detected in fecal supernatants of both the F. nucleatum-gavaged rats and the IBS-D patients. The FomA protein, which is a major outer membrane protein of F. nucleatum, was confirmed to react with the specific IgA of F. nucleatum in fecal supernatants. Conclusion: Fusobacterium increased significantly in IBS-D patients, and F. nucleatum was involved in the pathogenesis of IBS by causing microbial dysbiosis and exacerbating visceral hypersensitivity in a colonization-independent manner. Meanwhile, F. nucleatum was found to induce an increase in specific secretory IgA through FomA.

[Progresses on the effects and mechanisms of stress on gut microbiota].

Stress is the non-specific systemic response that occurs when the body is stimulated by various factors, and it can affect multiple systems of the body. Recent studies have shown that gut microbiota is an essential part of human microecology, and plays a pivotal role in keeping the body healthy. Stress can result in gut dysbiosis by affecting the function of intestinal mucosal barrier, intestinal immune and gastrointestinal motility. This article reviewed the alteration of gut microbiota caused by stress and the possible mechanisms involved.

Alterations in fecal short-chain fatty acids in patients with irritable bowel syndrome: A systematic review and meta-analysis.

BACKGROUND: Recent studies indicate that gut microbiota disorders potentially contribute to the pathogenesis of irritable bowel syndrome (IBS), which can be partly reflected by fecal short-chain fatty acids (SCFAs) generated from gut microbiota. Previous studies on SCFA alterations in patients with IBS have yielded conflicting results. No prior systematic review has been conducted on the alterations in fecal SCFAs in IBS patients. AIMS: We performed a meta-analysis to explore and clarify alterations in fecal SCFAs in IBS patients. METHODS: Case-control studies, randomized controlled trials (RCTs), and self-controlled studies were identified through electronic database searches. The standardized mean difference (SMD) with 95% confidence interval (CI) in fecal SCFA levels between different groups was calculated. RESULTS: The proportion of fecal propionate in patients with IBS was significantly higher than in healthy controls (HCs) (SMD = 0.44, 95% CI = 0.12, 0.76). A subgroup analysis showed that the concentration of fecal propionate (SMD = -0.91, 95% CI = -1.41, -0.41) and butyrate (SMD = -0.53, 95% CI = -1.01, -0.04) in patients with constipation-predominant IBS (IBS-C) was significantly lower than that in HCs, and the concentration of fecal butyrate in patients with diarrhea-predominant IBS (IBS-D) was higher than that in HCs (SMD = 0.34, 95% CI = 0.00, 0.67). Finally, we found that restricted diets correlated with fecal butyrate reduction in IBS (SMD = -0.26, 95% CI = -0.51, -0.01). CONCLUSIONS: In terms of fecal SCFAs, there were differences between patients with IBS and HCs. In IBS-C patients, propionate and butyrate were reduced, whereas butyrate was increased in IBS-D patients in comparison to HCs. Propionate and butyrate could be used as biomarkers for IBS diagnosis.

Beneficial effect of butyrate-producing Lachnospiraceae on stress-induced visceral hypersensitivity in rats.

BACKGROUND AND AIM: Emerging evidence indicates that psychological stress is involved in the pathogenesis of irritable bowel syndrome, which is characterized by visceral hypersensitivity and may be accompanied by gut dysbiosis. However, how such stress contributes to the development of visceral hypersensitivity is incompletely understood. Here, we aimed to investigate the influence that stress-induced microbial changes exert on visceral sensitivity, as well as the possible underlying mechanisms associated with this effect. METHODS: Male Sprague-Dawley rats underwent chronic water avoidance stress (WAS) to induce visceral hypersensitivity. Visceral sensitivity, colonic tight junction protein expression, and short-chain fatty acids of cecal contents were measured. Fecal samples were collected to characterize microbiota profiles. In a separate study, oral gavage of Roseburia in WAS rats was conducted to verify its potential role in the effectiveness on visceral hypersensitivity. RESULTS: Repeated WAS caused visceral hypersensitivity, altered fecal microbiota composition and function, and decreased occludin expression in the colon. Stressed rats exhibited reduced representation of pathways involved in the metabolism of butyrate and reduced abundance of several operational taxonomic units associated with butyrate-producing bacteria, such as Lachnospiraceae. Consistently, supplementation with Roseburia hominis, a species belonging to Lachnospiraceae, significantly increased cecal butyrate content. Moreover, Roseburia supplementation alleviated visceral hypersensitivity and prevented the decreased expression of occludin. CONCLUSIONS: Reduction in the abundance of butyrate-producing Lachnospiraceae, which is beneficial for the intestinal barrier, was involved in the formation of visceral hypersensitivity. R. hominis is a potential probiotic for treating stress-induced visceral hypersensitivity.

The effect of Clostridium butyricum on symptoms and fecal microbiota in diarrhea-dominant irritable bowel syndrome: a randomized, double-blind, placebo-controlled trial.

Irritable bowel syndrome (IBS) is a common disorder in gastrointestinal system and impairs the quality of life of the patients. Clostridium butyricum (CB) is a probiotics that has been used in several gastrointestinal diseases. The efficacy of CB in treating IBS is still unknown. This prospective, multi-centre, randomized, double-blind, placebo-controlled trial aimed to assess the efficacy and safety of CB in treating diarrhea-predominant IBS (IBS-D) and analyze the fecal microbiota after treatment. Two hundred patients with IBS-D were recruited and were given CB or placebo for 4 weeks. End points included change from baseline in IBS symptoms, quality of life, stool consistency and frequency. Compared with placebo, CB is effective in improving the overall IBS-D symptoms (-62.12 ± 74.00 vs. -40.74 ± 63.67, P = 0.038) as well as quality of life (7.232 ± 14.06 vs. 3.159 ± 11.73, P = 0.032) and stool frequency (-1.602 ± 1.416 vs. -1.086 ± 1.644, P = 0.035). The responder rates are found higher in CB compared with the placebo (44.76% vs. 30.53%, P = 0.042). The change in fecal microbiota was analyzed and function pathways of CB in treating IBS-D were predicted. In conclusion, CB improves overall symptoms, quality of life and stool frequency in IBS-D patients and is considered to be used as a probiotics in treating IBS-D clinically.