Proteobacteria Acts as a Pathogenic Risk-Factor for Chronic Abdominal Pain and Diarrhea in Post-Cholecystectomy Syndrome Patients: A Gut Microbiome Metabolomics Study

Enhancing insights into diseases through horizontal gene transfer event detection from gut microbiome

Horizontal gene transfer (HGT) phenomena pervade the gut microbiome and significantly impact human health. Yet, no current method can accurately identify complete HGT events, including the transferred sequence and the associated deletion and insertion breakpoints from shotgun metagenomic data. Here, we develop LocalHGT, which facilitates the reliable and swift detection of complete HGT events from shotgun metagenomic data, delivering an accuracy of 99.4%-verified by Nanopore data-across 200 gut microbiome samples, and achieving an average F1 score of 0.99 on 100 simulated data. LocalHGT enables a systematic characterization of HGT events within the human gut microbiome across 2098 samples, revealing that multiple recipient genome sites can become targets of a transferred sequence, microhomology is enriched in HGT breakpoint junctions (P-value = 3.3e-58), and HGTs can function as host-specific fingerprints indicated by the significantly higher HGT similarity of intra-personal temporal samples than inter-personal samples (P-value = 4.3e-303). Crucially, HGTs showed potential contributions to colorectal cancer (CRC) and acute diarrhoea, as evidenced by the enrichment of the butyrate metabolism pathway (P-value = 3.8e-17) and the shigellosis pathway (P-value = 5.9e-13) in the respective associated HGTs. Furthermore, differential HGTs demonstrated promise as biomarkers for predicting various diseases. Integrating HGTs into a CRC prediction model achieved an AUC of 0.87.

The gut-brain-axis: A positive relationship between gut microbial dysbiosis and glioblastoma brain tumour

The glioblastoma brain tumour (GBM) stands out as the most aggressive and resistant-to-treatment malignancy. Nevertheless, the gut-brain connection plays a pivotal role in influencing the growth and activation of the central nervous system. In this particular investigation, we aimed to assess and characterize the gut microbial ecosystem in GBM patients, both quantitatively and qualitatively. We collected faecal samples from 15 healthy volunteers and 25 GBM patients. To delve into the microbial content, we employed PCR-DGGE, targeting the V3 region of the 16S rRNA gene, and conducted qPCR to measure the levels of crucial intestinal bacteria. For a more in-depth analysis, high-throughput sequencing was performed on a selection of 20 random faecal samples (10 from healthy individuals and 10 from GBM patients), targeting the V3+V4 region of the 16S rRNA gene. Our findings from examining the richness and diversity of the gut microbiota unveiled that GBM patients exhibited significantly higher microbial diversity compared to healthy individuals. At the phylum level, Proteobacteria saw a significant increase, while Firmicutes experienced a noteworthy decrease in the GBM group. Moving down to the family level, we observed significantly elevated levels of Enterobacteriaceae, Bacteroidaceae, and Lachnospiraceae in GBM patients, while levels of Veillonellaceae, Rikenellaceae, and Prevotellaceae were notably lower. Delving into genera statistics, we noted a substantial increase in the abundance of Parasutterella, Escherichia-Shigella, and Bacteroides, alongside significantly lower levels of Ruminococcus 2, Faecalibacterium, and Prevotella_9 in the GBM group compared to the control group. Furthermore, when examining specific species, we found a significant increase in Bacteroides vulgatus and Escherichia coli in the GBM group. These observations collectively indicate a marked dysbiosis in the gut microbial composition of GBM patients. Additionally, the GBM group exhibited notably higher levels of alpha diversity when compared to the control group. This increase in diversity suggests a significant bacterial overgrowth in the gut of GBM patients in contrast to the controls. As a result, this research opens up potential avenues to gain a better understanding of the underlying mechanisms, pathways, and potential treatments for GBM, stemming from the significant implications of gut microbial dysbiosis in these patients.

Current understanding of the molecular mechanisms of chemotherapy-induced peripheral neuropathy

Chemotherapy-induced peripheral neuropathy (CIPN) is the most common off-target adverse effects caused by various chemotherapeutic agents, such as cisplatin, oxaliplatin, paclitaxel, vincristine and bortezomib. CIPN is characterized by a substantial loss of primary afferent sensory axonal fibers leading to sensory disturbances in patients. An estimated of 19-85% of patients developed CIPN during the course of chemotherapy. The lack of preventive measures and limited treatment options often require a dose reduction or even early termination of life-saving chemotherapy, impacting treatment efficacy and patient survival. In this Review, we summarized the current understanding on the pathogenesis of CIPN. One prominent change induced by chemotherapeutic agents involves the disruption of neuronal cytoskeletal architecture and axonal transport dynamics largely influenced by the interference of microtubule stability in peripheral neurons. Due to an ineffective blood-nerve barrier in our peripheral nervous system, exposure to some chemotherapeutic agents causes mitochondrial swelling in peripheral nerves, which lead to the opening of mitochondrial permeability transition pore and cytochrome c release resulting in degeneration of primary afferent sensory fibers. The exacerbated nociceptive signaling and pain transmission in CIPN patients is often linked the increased neuronal excitability largely due to the elevated expression of various ion channels in the dorsal root ganglion neurons. Another important contributing factor of CIPN is the neuroinflammation caused by an increased infiltration of immune cells and production of inflammatory cytokines. In the central nervous system, chemotherapeutic agents also induce neuronal hyperexcitability in the spinal dorsal horn and anterior cingulate cortex leading to the development of central sensitization that causes CIPN. Emerging evidence suggests that the change in the composition and diversity of gut microbiota (dysbiosis) could have direct impact on the development and progression of CIPN. Collectively, all these aspects contribute to the pathogenesis of CIPN. Recent advances in RNA-sequencing offer solid platform for in silico drug screening which enable the identification of novel therapeutic agents or repurpose existing drugs to alleviate CIPN, holding immense promises for enhancing the quality of life for cancer patients who undergo chemotherapy and improve their overall treatment outcomes.

Microbiota profiling reveals alteration of gut microbial neurotransmitters in a mouse model of autism-associated 16p11.2 microduplication

The gut-brain axis is evident in modulating neuropsychiatric diseases including autism spectrum disorder (ASD). Chromosomal 16p11.2 microduplication 16p11.2dp/+ is among the most prevalent genetic copy number variations (CNV) linked with ASD. However, the implications of gut microbiota status underlying the development of ASD-like impairments induced by 16p11.2dp/+ remains unclear. To address this, we initially investigated a mouse model of 16p11.2dp/+, which exhibits social novelty deficit and repetitive behavior characteristic of ASD. Subsequently, we conducted a comparative analysis of the gut microbial community and metabolomic profiles between 16p11.2dp/+ and their wild-type counterparts using 16S rRNA sequencing and liquid chromatography-mass spectrometry (LC/MS). Our microbiota analysis revealed structural dysbiosis in 16p11.2dp/+ mice, characterized by reduced biodiversity and alterations in species abundance, as indicated by α/β-diversity analysis. Specifically, we observed reduced relative abundances of Faecalibaculum and Romboutsia, accompanied by an increase in Turicibacter and Prevotellaceae UCG_001 in 16p11.2dp/+ group. Metabolomic analysis identified 19 significantly altered metabolites and unveiled enriched amino acid metabolism pathways. Notably, a disruption in the predominantly histamine-centered neurotransmitter network was observed in 16p11.2dp/+ mice. Collectively, our findings delineate potential alterations and correlations among the gut microbiota and microbial neurotransmitters in 16p11.2dp/+ mice, providing new insights into the pathogenesis of and treatment for 16p11.2 CNV-associated ASD.

Diagnosis and treatment of post-cholecystectomy diarrhoea

The incidence of cholecystitis is relatively high in developed countries and may usually be attributed to gallstones, the treatment for which involves complete surgical removal of the gallbladder (cholecystectomy). Bile acids produced following cholecystectomy continue to flow into the duodenum but are poorly absorbed by the colon. Excessive bile acids in the colon stimulate mucosal secretion of water and electrolytes leading, in severe cases, to diarrhoea. Bile acid diarrhoea (BAD) is difficult to diagnose, requiring a comprehensive medical history and physical examination in combination with laboratory evaluation. The current work reviews the diagnosis and treatment of BAD following cholecystectomy.

Cholecystectomy Significantly Alters Gut Microbiota Homeostasis and Metabolic Profiles: A Cross-Sectional Study

Cholecystectomy (CCE) is a standard clinical treatment for conditions like gallstones and cholecystitis. However, its link to post-CCE syndrome, colorectal cancer, and nonalcoholic fatty liver disease has raised concerns. Additionally, studies have demonstrated the disruptive effects of CCE on gut microbiota homeostasis and bile acid (BA) metabolism. Considering the role of gut microbiota in regulating host metabolic and immune pathways, the use of dietary and probiotic intervention strategies to maintain a stable gut ecosystem after CCE could potentially reduce associated disease risks. Inter-study variations have made it challenging to identify consistent gut microbiota patterns after CCE, a prerequisite for targeted interventions. In this study, we first meta-analyzed 218 raw 16S rRNA gene sequencing datasets to determine consistent patterns of structural and functional changes in the gut microbiota after CCE. Our results revealed significant alterations in the gut microbiota's structure and function due to CCE. Furthermore, we identified characteristic gut microbiota changes associated with CCE by constructing a random model classifier. In the validation cohort, this classifier achieved an area under the receiver operating characteristic curve (AUC) of 0.713 and 0.683 when distinguishing between the microbiota of the CCE and healthy groups at the family and genus levels, respectively. Further, fecal metabolomics analysis demonstrated that CCE also substantially modified the metabolic profile, including decreased fecal short-chain fatty acid levels and disrupted BA metabolism. Importantly, dietary patterns, particularly excessive fat and total energy intake, influenced gut microbiota and metabolic profile changes post-CCE. These dietary habits were associated with further enrichment of the microbiota related to BA metabolism and increased levels of intestinal inflammation after CCE. In conclusion, our study identified specific alterations in gut microbiota homeostasis and metabolic profiles associated with CCE. It also revealed a potential link between dietary patterns and gut microbiota changes following CCE. Our study provides a theoretical basis for modulating gut microbiota homeostasis after CCE using long-term dietary strategies and probiotic interventions.

Prevalence and Factors Associated With Post-Cholecystectomy Syndrome in Saudi Arabia

OBJECTIVES

Post-cholecystectomy syndrome (PCS) refers to the continuation or recurrence of biliary colic and any other gastrointestinal symptoms present prior to cholecystectomy. Given that PCS is rare and underestimated in Saudi Arabia, this study aimed to determine the prevalence of PCS among Saudis.

METHODS

This cross-sectional study included randomly gathered subjects who self-administered the validated European Organization for Research and Treatment of Cancer QLQ-C30 questionnaire from September 6 to October 7, 2022.

RESULTS

A total of 518 participants who underwent cholecystectomies were included; most were female (73.6%), 153 (29.5%) were 19 to 25 years old, and the vast majority were Saudi Arabian (91.1%). The average preoperative weight was 71 ± 20.7 kg (range 20 to 258), and the mean current weight was 69 ± 19.4 kg (range 30 to 257). About 137 (26.4%) had a chronic disease, most frequently hypertension (37.2%). In the past week, most participants experienced some trouble doing strenuous activities (42.9%), slight pain (37.6%), fatigue (32.2%), insomnia (37.5%), and weakness (38.2%). There were no significant associations between age, nationality, or residence with the QLQ-C30 score (P-value = 0.152, 0.262, 0.071, respectively). A significant association was observed between gender and QLQ-C30 score (P-value < 0.001), with females scoring higher than their male counterparts. Females also reported having a higher quality of life than males.

CONCLUSIONS

The prevalence of PCS was higher than reported elsewhere.

Detection of Colistin Sulfate on Piglet Gastrointestinal Tract Microbiome Alterations

The gut microbiome exerts important functions on host health maintenance, whereas excessive antibiotic use may cause gut flora dysfunction resulting in serious disease and dysbiosis. Colistin is a broad-spectrum antibiotic with serious resistance phenomena. However, it is unclear whether colistin alters the gastrointestinal tract microbiome in piglets. In this study, 16s rDNA-based metagenome analyses were used to assess the effects of colistin on the modification of the piglet microbiome in the stomach, duodenum, jejunum, cecum, and feces. Both α- and β-diversity indices showed that colistin modified microbiome composition in these gastrointestinal areas. In addition, colistin influenced microbiome composition at the phylum and genus levels. At the species level, colistin upregulated Mycoplasma hyorhinis, Chlamydia trachomatis, Lactobacillus agilis, Weissella paramesenteroides, and Lactobacillus salivarius abundance, but downregulated Actinobacillus indolicus, Campylobacter fetus, Glaesserella parasuis, Moraxella pluranimalium, Veillonella caviae, Neisseria dentiae, and Prevotella disiens abundance in stomachs. Colistin-fed piglets showed an increased abundance of Lactobacillus mucosae, Megasphaera elsdenii DSM 20460, Fibrobacter intestinalis, and Unidentified rumen bacterium 12-7, but Megamonas funiformis, Uncultured Enterobacteriaceae bacterium, Actinobacillus porcinus, Uncultured Bacteroidales bacterium, and Uncultured Clostridiaceae bacterium abundance was decreased in the cecum. In feces, colistin promoted Mucispirillum schaedleri, Treponema berlinense, Veillonella magna, Veillonella caviae, and Actinobacillus porcinus abundance when compared with controls. Taken together, colistin modified the microbiome composition of gastrointestinal areas in piglets. This study provides new clinical rationalization strategies for colistin on the maintenance of animal gut balance and human public health.

Post-cholecystectomy syndrome: A cohort study from a single private tertiary center

Objectives

Although post-cholecystectomy syndrome (PCS) is a well-recognized complication, there are few reports arising from KSA. The effect of sleeve gastrectomy or endoscopic retrograde cholangiopancreatography (ERCP) stenting on the development of PCS is unknown. We aimed to measure the possible factors affecting the development of PCS, such as symptom duration, comorbidities, previous bariatric surgery, ERCP stent insertion, surgical intervention, conversion to open surgery and complication rate.

Methods

This was a prospective cohort and observational study conducted at a single, private tertiary center. We included 167 patients who underwent surgery for gallbladder disease between October 2019 and June 2020. The patients were classified into two groups according to their PCS status (PCS+ vs. PCS-).

Results

Thirty-nine patients were PCS+ (23.3%). There was no significant difference between the two groups with regards to age, gender, BMI, ASA score, smoking, comorbidities, duration of symptoms, previous bariatric surgery, ERCP, stent insertion or sphincterotomy. Chronic cholecystitis was the predominant histopathology in 83% (139/167) of patients. The most frequent causes of PCS included biliary system dysfunction, bile salt-induced diarrhea, gastritis, gastroesophageal reflux disease, and retained stones. Overall, 71.8% (28/39) of patients had incident PCS; the remaining patients had persistent PCS.

Conclusions

PCS is a neglected complication that was observed in 25% of patients mainly in the first year. Surgeon awareness can assist with patient diagnosis, preoperative selection and education. Furthermore, the history of ERCP stenting, sphincterotomy, or sleeve gastrectomy seems to be unrelated to PCS development.

A systematic review on omics data (metagenomics, metatranscriptomics, and metabolomics) in the role of microbiome in gallbladder disease

Microbiotas are the range of microorganisms (mainly bacteria and fungi) colonizing multicellular, macroscopic organisms. They are crucial for several metabolic functions affecting the health of the host. However, difficulties hamper the investigation of microbiota composition in cultivating microorganisms in standard growth media. For this reason, our knowledge of microbiota can benefit from the analysis of microbial macromolecules (DNA, transcripts, proteins, or by-products) present in various samples collected from the host. Various omics technologies are used to obtain different data. Metagenomics provides a taxonomical profile of the sample. It can also be used to obtain potential functional information. At the same time, metatranscriptomics can characterize members of a microbiome responsible for specific functions and elucidate genes that drive the microbiotas relationship with its host. Thus, while microbiota refers to microorganisms living in a determined environment (taxonomy of microorganisms identified), microbiome refers to the microorganisms and their genes living in a determined environment and, of course, metagenomics focuses on the genes and collective functions of identified microorganisms. Metabolomics completes this framework by determining the metabolite fluxes and the products released into the environment. The gallbladder is a sac localized under the liver in the human body and is difficult to access for bile and tissue sampling. It concentrates the bile produced in the hepatocytes, which drains into bile canaliculi. Bile promotes fat digestion and is released from the gallbladder into the upper small intestine in response to food. Considered sterile originally, recent data indicate that bile microbiota is associated with the biliary tract’s inflammation and carcinogenesis. The sample size is relevant for omic studies of rare diseases, such as gallbladder carcinoma. Although in its infancy, the study of the biliary microbiota has begun taking advantage of several omics strategies, mainly based on metagenomics, metabolomics, and mouse models. Here, we show that omics analyses from the literature may provide a more comprehensive image of the biliary microbiota. We review studies performed in this environmental niche and focus on network-based approaches for integrative studies.

Mechanism of Action of Shenerjiangzhi Formulation on Hyperlipidemia Induced by Consumption of a High-Fat Diet in Rats Using Network Pharmacology and Analyses of the Gut Microbiota

Shenerjiangzhi formulation (SEJZ) is a new traditional Chinese medicine formulation (patent number: CN110680850A). SEJZ contains Eleutherococcus senticosus (Rupr. and Maxim.), Maxim (Araliaceae; E. senticosus radix and rhizome), Lonicera japonica Thunb (Caprifoliaceae; Lonicera japonica branch, stem), Crataegus pinnatifida Bunge (Rosaceae; Crataegus pinnatifida fruit), and Auricularia auricula. SEJZ has been designed to treat hyperlipidemia. Despite the therapeutic benefits of SEJZ, its underlying mechanism of action is not known. We explored the efficacy of SEJZ against hyperlipidemia by integrating network pharmacology and 16S rRNA gene sequencing and elucidated its mechanism of action. First, SEJZ targets were found through the Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform and from the literature. Hyperlipidemia-related therapeutic targets were obtained from GeneCards, Online Mendelian Inheritance in Man, and DrugBank databases. Then, Search Tool for the Retrieval of Interacting Genes/Proteins and Cytoscape were applied for the analyses and construction of a protein–protein interaction (PPI) network. The Kyoto Encyclopedia of Genes and Genomes database was employed to identify signaling pathways that were enriched. Second, the therapeutic effects of SEJZ against hyperlipidemia induced by consumption of a high-fat diet in rats were evaluated by measuring body weight changes and biochemical tests. SEJZ treatment was found to alleviate obesity and hyperlipidemia in rats. Finally, 16S rRNA gene sequencing showed that SEJZ could significantly increase the abundance of short-chain fatty acid-producing bacteria, restore the intestinal barrier, and maintain intestinal-flora homeostasis. Using PICRUSt2, six metabolic pathways were found to be consistent with the results of network pharmacology: “African trypanosomiasis”, “amoebiasis”, “arginine and proline metabolism”, “calcium signaling pathway”, “NOD-like receptor signaling pathway”, and “tryptophan metabolism”. These pathways might represent how SEJZ works against hyperlipidemia. Moreover, the “African trypanosomiasis pathway” had the highest association with core genes. These results aid understanding of how SEJZ works against dyslipidemia and provide a reference for further studies.

Effects of Lacidophilin Tablets, Yogurt, and Bifid Triple Viable Capsules on the Gut Microbiota of Mice with Antibiotic-Associated Diarrhea

Antibiotic-associated diarrhea (AAD) is a common morbidity caused by antibiotic use and is characterized by the dysbiosis of the gut microbiota. Several clinical trials have shown that probiotics can prevent AAD. This study aimed at investigating the effects of Lacidophilin tablets (LB), yogurt (YG), and bifid triple viable capsules (BT) on the gut microbiota of mice with AAD. Mice with diarrhea were randomly allocated to treatment groups or the control group and were treated with either LB, YG, BT, or vehicle control. The body weight, diarrhea scores, cecum index, and cecal length were determined. Fecal samples of all mice were analyzed using 16S rRNA high-throughput sequencing. The results showed that LB, YG, and BT significantly decreased the diarrhea scores and inhibited increases in the cecum index and cecal length induced by AAD. In addition, they significantly changed the composition and richness of the gut microbiota. Specifically, they increased the abundance of the phylum Firmicutes and decreased the abundance of the phyla Bacteroidetes and the family Bacteroidaceae. Treatment with LB and YG also decreased the abundance of the phylum Proteobacteria and only LB could mediate the reduced levels of Lactobacillaceae in AAD mice. At the genus level, YG and BT treatment decreased the abundance of Bacteroides or Parasutterella. To our surprise, only LB treatment dramatically increased the abundance of Lactobacillus and decreased that of potential pathogens, such as Bacteroides, Parabacteroides, and Parasutterella, to almost normal values. Our findings indicate that LB, YG, and BT ameliorated diarrhea by regulating the composition and structure of the gut microbiota and that LB plays an important role in regulating the gut microbiota.

Dyspepsia and Gut Microbiota in Female Patients with Postcholecystectomy Syndrome

BACKGROUND

Gallstone disease (GSD) represents one of the most frequent digestive disorders, highly reported in female gender. The purpose of the study was to explore the clinical and gut microbiota particularities of female patients with postcholecystectomy syndrome (PCS) and the possible relationship between gut dysbiosis (DB) and abdominal complaints.

PATIENTS AND METHODS

In total, 129 female participants: 104 outpatients divided into two equal groups, 52 PCS (+), 52 PCS (-) and 25 healthy controls were consecutively enrolled in this observational study. Patients underwent clinical examination with assessment of pain, bloating, transit disturbances, abdominal ultrasound/computer tomography/magnetic resonance imaging/endoscopic retrograde cholangiopancreatography, upper and lower digestive endoscopies. Laboratory work-ups and stool microbiology assessments were performed for all study participants (patients and controls). Stool microorganisms were identified by matrix-assisted laser desorption ionization - time-of-flight- mass spectrometry and in patients with DB also by next-generation sequencing.

RESULTS

Older age, complicated gallstones disease, associated conditions like diabetes mellitus/impaired glucose tolerance and irritable bowel syndrome were significantly present in PCS (+) group, as well as sedentary lifestyle and diets characterized by a low fiber intake (p<0.0001). PCS (+) patients displayed significant differences related to the incidence and severity of overall gut microbiota DB, decreased H index of biodiversity and the unbalanced Firmicutes/Bacteroidetes (F/B) ratios by comparison to the PCS (-) group (p<0.0001). Strong positive correlations of the severity of overall DB with bloating and the intestinal habit disorders, as well as of F/B ratios to all abdominal symptoms were noted.

CONCLUSION

PCS in female patients was associated with older age, sedentary lifestyle, specific dietary habits, history of complicated gallstone disease, diabetes mellitus/impaired glucose tolerance and irritable bowel syndrome, as well as gut microbiota particularities. Overall DB and unbalanced F/B ratios were strongly correlated to abdominal complaints.

Indole-3-propionic Acid-aggravated CCl4-induced Liver Fibrosis via the TGF-β1/Smads Signaling Pathway

BACKGROUND AND AIMS

The pathogenesis of liver fibrosis involves liver damage, inflammation, oxidative stress, and intestinal dysfunction. Indole-3-propionic acid (IPA) has been demonstrated to have antioxidant, anti-inflammatory and anticancer activities, and a role in maintaining gut homeostasis. The current study aimed to investigate the role of IPA in carbon tetrachloride (CCl₄)-induced liver fibrosis and explore the underlying mechanisms.

METHODS

The liver fibrosis model was established in male C57BL/6 mice by intraperitoneal injection of CCl₄ twice weekly. IPA intervention was made orally (20 mg/kg daily). The degree of liver injury and fibrosis were assessed by serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), and histopathology. Enzyme-linked immunosorbent assay and quantitative real-time polymerase chain reaction (qPCR) were used to detect the inflammatory cytokines. The malondialdehyde (MDA), glutathione, glutathione peroxidase, superoxide dismutase, and catalase were determined via commercial kits. Hepatocyte apoptosis was detected by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling assay. The expression of mRNA and protein was assayed by qPCR, Western blotting, or immunohistochemical staining.

RESULTS

After IPA treatment, the ALT and AST, apoptotic cells, and pro-inflammatory factor levels were enhanced significantly. Moreover, IPA intervention up-regulated the expression of collagen I, α-smooth muscle actin, tissue inhibitor of matrix metalloproteinase-1, matrix metalloproteinase-2, transforming growth factor-β1 (TGF-β1), Smad3, and phosphorylated-Smad2/3. Additionally, IPA intervention did not affect the MDA level. Attractively, the administration of IPA remodeled the gut flora structure.

CONCLUSIONS

IPA aggravated CCl₄-induced liver damage and fibrosis by activating HSCs via the TGF-β1/Smads signaling pathway.

HMB Improves Lipid Metabolism of Bama Xiang Mini-Pigs via Modulating the Bacteroidetes-Acetic Acid-AMPKα Axis

Here, we used Bama Xiang mini-pigs to explore the effects of different dietary β-hydroxy-β-methylbutyrate (HMB) levels (0, 0.13, 0.64 or 1.28%) on lipid metabolism of adipose tissue. Results showed that HMB decreased the fat percentage of pigs (linearly, P < 0.05), and the lowest value was observed in the 0.13% HMB group. Moreover, the colonic acetic acid concentration and the relative Bacteroidetes abundance were increased in response to HMB supplementation (P < 0.05). Correlation analysis identified a positive correlation between the relative Bacteroidetes abundance and acetic acid production, and a negative correlation between fat percentage and the relative Bacteroidetes abundance or acetic acid production. HMB also upregulated the phosphorylation (p) of AMPKα, Sirt1, and FoxO1, and downregulated the p-mTOR expression. Collectively, these findings indicate that reduced fat percentage in Bama Xiang mini-pigs could be induced by HMB supplementation and the mechanism might be associated with the Bacteroidetes-acetic acid-AMPKα axis.

Risk of Heart Disease after Cholecystectomy: A Nationwide Population-Based Cohort Study in South Korea

The aim of the study is to evaluate the risk of heart disease in individuals who underwent cholecystectomy. This was a retrospective cohort study using the National Health Insurance Service database of South Korea. A total of 146,928 patients who underwent cholecystectomy and 268,502 age- and sex-matched controls were compared. Multivariate Cox proportional hazard regression analysis was used to estimate the hazard ratio (HR) and 95% confidence interval (CI) for heart disease after cholecystectomy. In results, a previous history of cholecystectomy increased the risk of heart disease (congestive heart failure [CHF], myocardial infarction [MI], atrial fibrillation [AF]) (adjusted HR [aHR]: 1.40, 95% CI: [1.36–1.44]). The increased risk was particularly seen for CHF (1.22 [1.16–1.29]) but not for MI and AF (p > 0.05). In the subgroup analyses, cholecystectomy was associated with an increased risk of MI in patients aged <65 years (1.49 [1.16–1.92] and 1.18 [1.05–1.35] in patients aged 40–49 and 50–64 years, respectively), but not in those aged ≥ 65 years (0.932 [0.838–1.037]). Moreover, the risk of MI was increased in patients without diabetes mellitus (DM) (1.16 [1.06–1.27]); however, it was decreased in patients with DM (0.83 [0.72–0.97]). In contrast, cholecystectomy did not modify the risk of AF in the subgroup analyses (all p > 0.05). In conclusion, a history of cholecystectomy is associated with an increased risk of CHF. Cholecystectomy may increase the risk of MI in the younger population without DM. These findings suggest that the alteration of bile metabolism and homeostasis might be potentially associated with the development of some heart diseases.

Fecal Bacterial Microbiota of Healthy Free-Ranging, Healthy Corralled, and Chronic Diarrheic Corralled Rhesus Macaques (Macaca mulatta)

A clinical challenge to nearly every primate facility in North America is chronic idiopathic diarrhea (CID), the pathogenesis of which has yet to be fully elucidated. However, wild macaques appear resistant to CID, a trend that we observed in the free-ranging population of the Caribbean Primate Research Center. The gastrointestinal microbiota has been shown to have a significant role in the pathogenesis of disease and in maintaining normal health and development of the gut. In humans, chronic diarrhea is associated with alteration of the gut microbiota, which has lower bacterial diversity than does the microbiota of healthy humans. The current study was designed to describe and compare the fecal bacterial microbiota of healthy corralled, CID corralled, and healthy, free-ranging macaques. Fresh fecal samples were collected from healthy corralled (HC; n = 30) and CID (n = 27) rhesus macaques and from healthy macaques from our free-ranging colony (HF; n = 43). We excluded macaques that had received antibiotics during the preceding 60 d (90 d for healthy animals). Bacterial DNA was extracted, and the V4 region of the 16S rRNA gene was sequenced and compared with known databases. The relative abundance of Proteobacteria was higher in CID animals than HC animals, but otherwise few differences were found between these 2 groups. HF macaques were differentially enriched with Christensenellaceae and Helicobacter, which are highly associated with a 'healthy' gut in humans, as compared to corralled animals, whereas CID animals were enriched with Proteobacteria, which are associated with dysbiosis in other species. These results indicate that environment has a greater influence than health status on the gut microbiota. Furthermore, the current data provided targets for future studies on potential clinical interventions, such as probiotics and fecal transplants.

Development of a novel model of cholecystectomy in subsequently ovariectomized mice and characterization of metabolic and gastrointestinal phenotypes: a pilot study

Background

Cholecystectomy (XGB) is the most common abdominal surgery performed in the United States and is associated with an increased post-surgery incidence of metabolic and gastrointestinal (GI) diseases. Two main risk factors for XGB are sex (female) and age (40–50 yr), corresponding with onset of menopause. Post-menopausal estrogen loss alone facilitates metabolic dysfunction, but the effects of XGB on metabolic and GI health have yet to be investigated in this population. Study objectives were to (1) identify possible short-term effects of XGB and (2) develop a novel murine model of XGB in human menopause via subsequent ovariectomy (OVX) and assess longitudinal effects of OVX on metabolism, GI physiology, and GI microbiota in XGB mice.

Methods

Female C57BL/6 mice were utilized in two parallel studies (S1&S2). In S1, XGB mice were compared to a non-XGB baseline group after six wk. In S2, mice were XGB at wk0, either sham (SHM) or OVX at wk6, and sacrificed at wk12, wk18, and wk24. Body composition assessment and fresh fecal collections were conducted periodically. Serum and tissues were collected at sacrifice for metabolic and GI health endpoints.

Results

Compared to baseline, XGB increased hepatic CYP7A1 and decreased HMGCR relative expression, but did not influence BW, fat mass, or hepatic triglycerides after six wk. In S2, XGB/OVX mice had greater BW and fat mass than XGB/SHM. Cecal microbiota alpha diversity metrics were lower in XGB/OVX mice at wk24 compared the XGB/SHM. No consistent longitudinal patterns in fasting serum lipids, fecal microbial diversity, and GI gene expression were observed between S2 groups.

Conclusions

In addition to developing a novel, clinically-representative model of XGB and subsequent OVX, our results suggest that OVX resulted in the expected phenotype to some extent, but that XGB may modify or mask some responses and requires further investigation.

Gallstone Disease, Obesity and the Firmicutes/Bacteroidetes Ratio as a Possible Biomarker of Gut Dysbiosis

Obesity is a major risk factor for developing gallstone disease (GSD). Previous studies have shown that obesity is associated with an elevated Firmicutes/Bacteroidetes ratio in the gut microbiota. These findings suggest that the development of GSD may be related to gut dysbiosis. This review presents and summarizes the recent findings of studies on the gut microbiota in patients with GSD. Most of the studies on the gut microbiota in patients with GSD have shown a significant increase in the phyla Firmicutes (Lactobacillaceae family, genera Clostridium, Ruminococcus, Veillonella, Blautia, Dorea, Anaerostipes, and Oscillospira), Actinobacteria (Bifidobacterium genus), Proteobacteria, Bacteroidetes (genera Bacteroides, Prevotella, and Fusobacterium) and a significant decrease in the phyla Bacteroidetes (family Muribaculaceae, and genera Bacteroides, Prevotella, Alistipes, Paludibacter, Barnesiella), Firmicutes (genera Faecalibacterium, Eubacterium, Lachnospira, and Roseburia), Actinobacteria (Bifidobacterium genus), and Proteobacteria (Desulfovibrio genus). The influence of GSD on microbial diversity is not clear. Some studies report that GSD reduces microbial diversity in the bile, whereas others suggest the increase in microbial diversity in the bile of patients with GSD. The phyla Proteobacteria (especially family Enterobacteriaceae) and Firmicutes (Enterococcus genus) are most commonly detected in the bile of patients with GSD. On the other hand, the composition of bile microbiota in patients with GSD shows considerable inter-individual variability. The impact of GSD on the Firmicutes/Bacteroidetes ratio is unclear and reports are contradictory. For this reason, it should be stated that the results of reviewed studies do not allow for drawing unequivocal conclusions regarding the relationship between GSD and the Firmicutes/Bacteroidetes ratio in the microbiota.

Propionate inhibits fat deposition via affecting feed intake and modulating gut microbiota in broilers

As one of the 3 main short-chain fatty acids, the role of propionate in chicken fat metabolism is largely unknown. In this study, we demonstrated that dietary supplementation of coated sodium propionate (SP) moderately inhibits fat deposition in broiler chickens, as evidenced by the decreased adipocyte mean area (P < 0.01), the lowered triglyceride content in abdominal fat tissue (P < 0.01), and the reduced transcription of several lipogenic genes in liver and abdominal fat tissues (P < 0.05). Surprisingly, the propionate content was not significantly elevated either in serum or in the cecal chyme by SP administration (P > 0.05). However, SP application significantly decreased the average daily feed intake of broilers (P < 0.05). In addition, the composition of the cecal microbial communities was altered, with the ratio of Firmicutes to Bacteroidetes decreasing in particular (P < 0.05). At the genus level, SP application increased the richness of Alistipes, Lactobacillus, and Bifidobacterium, while reduced the abundance of Lachnospiraceae and Helicobacter significantly (P < 0.05). Moreover, in vitro experiments indicated that, although physiological concentrations of propionate (0.01 to 0.1 mmol) upregulated or downregulated the transcription of some fat synthesis-associated genes (P < 0.05), they did not significantly affect the triglyceride accumulation in hepatocytes and adipocytes (P > 0.05). These results suggest that feed supplementation with SP inhibits fat deposition in broilers by reducing feed and caloric intake, but not via direct regulation on hepatic fat synthesis or adipocytic fat deposition. Alteration in the relative populations of the gut microflora suggests that SP may have gut health implications.

The Role of Bacteria and Its Derived Metabolites in Chronic Pain and Depression: Recent Findings and Research Progress

BACKGROUND

Chronic pain is frequently comorbid with depression in clinical practice. Recently, alterations in gut microbiota and metabolites derived therefrom have been found to potentially contribute to abnormal behaviors and cognitive dysfunction via the "microbiota-gut-brain" axis.

METHODS

PubMed was searched and we selected relevant studies before October 1, 2019. The search keyword string included "pain OR chronic pain" AND "gut microbiota OR metabolites"; "depression OR depressive disorder" AND "gut microbiota OR metabolites". We also searched the reference lists of key articles manually.

RESULTS

This review systematically summarized the recent evidence of gut microbiota and metabolites in chronic pain and depression in animal and human studies. The results showed the pathogenesis and therapeutics of chronic pain and depression might be partially due to gut microbiota dysbiosis. Importantly, bacteria-derived metabolites, including short-chain fatty acids, tryptophan-derived metabolites, and secondary bile acids, offer new insights into the potential linkage between key triggers in gut microbiota and potential mechanisms of depression.

CONCLUSION

Studying gut microbiota and its metabolites has contributed to the understanding of comorbidity of chronic pain and depression. Consequently, modulating dietary structures or supplementation of specific bacteria may be an available strategy for treating chronic pain and depression.