Changes in the colon microbiota and intestinal cytokine gene expression following minimal intestinal surgery

Does Microbiome Matter in Chronic Intestinal Failure Due to Type 1 Short Bowel Syndrome in Adults?

The exact microbiome composition and function of patients with Short Bowel Syndrome (SBS) and Chronic Intestinal Failure (CIF) are still unknown. Patients with type I SBS-CIF (end-jejunostomy/ileostomy) are little represented in available studies. The aim of this study is to evaluate the microbiome characteristics of adult type 1 SBS-CIF patients according to their clinical features. Fecal microbiota was studied by amplicon-based sequencing and volatile organic compounds (VOCs) were assessed by solid-phase microextraction and gas chromatography-mass spectrometry. A total of 44 adult type 1 SBS-CIF patients were enrolled. At the family level, Lactobacillaceae (38% of the relative frequency) and Streptococcaceae (24%) were predominant; at the genus level, Streptococcus (38% of the relative frequency) and Lactobacillus (24%) were the dominant amplicon sequence variants (ASVs). Patients with increased stomal output showed higher ASVs for Lactobacillus (Rho = +0.38; p = 0.010), which was confirmed after adjusting for small bowel length (OR = 1.04; 95% CI 1.01-1.07, p = 0.023). Hyperphagia was associated with higher concentrations of short-chain fatty acid (SCFA) esters, such as butanoic acid ethyl ester (p = 0.005) and hexanoic acid ethyl ester (p = 0.004). Dietary fiber intake was directly correlated with most VOCs. Hyperphagia was associated with dietary fiber, after adjusting for small bowel length (OR = 1.35; 95% CI 1.01-1.81; p = 0.040). In type 1 SBS-CIF patients, a greater frequency of Lactobacilli was associated with increased stomal outputs, while increased fiber intake and concentrations of SCFA esters were associated with hyperphagia. These results might have implications for clinical practice.

Bile Acids and Microbiota Interplay in Pancreatic Cancer

Evidence suggests the involvement of the microbiota, including oral, intra-tumoral and gut, in pancreatic cancer progression and response to therapy. The gut microbiota modulates the bile acid pool and is associated with maintaining host physiology. Studies have shown that the bile acid/gut microbiota axis is dysregulated in pancreatic cancer. Bile acid receptor expression and bile acid levels are dysregulated in pancreatic cancer as well. Studies have also shown that bile acids can cause pancreatic cell injury and facilitate cancer cell proliferation. The microbiota and its metabolites, including bile acids, are also altered in other conditions considered risk factors for pancreatic cancer development and can alter responses to chemotherapeutic treatments, thus affecting patient outcomes. Altogether, these findings suggest that the gut microbial and/or bile acid profiles could also serve as biomarkers for pancreatic cancer detection. This review will discuss the current knowledge on the interaction between gut microbiota interaction and bile acid metabolism in pancreatic cancer.

The Role of Probiotics in Inflammation Associated with Major Surgery: A Narrative Review

Background: Gut microbiota is well-known for its ability to maintain intestinal homeostasis. However, the disruption of this homeostasis, known as dysbiosis, leads to multiple consequences, including local and systemic inflammation. Surgery-induced inflammation is a major concern for patients, as it leads to many infectious and non-infectious complications. Objective: The purpose of this review was to explore the role of probiotics and symbiotics in surgery-induced inflammation and to determine if their use is effective in combatting inflammation and its complications Methods and Materials: A literature search was conducted, and articles published only in English, until December 2022 were included. The results are reported in the form of a narrative review. Results: The perioperative use of probiotics and/or symbiotics results in lower risk of infectious complications, including reduced rates of surgical site infections, respiratory and urinary tract infections, shorter hospital stays, and fewer days of antibiotic administration. It also contributes to reducing non-infectious complications, as it mitigates systemic and local inflammation via maintenance of the intestinal barrier, improves intestinal mobility, and is associated with lower rates of postoperative pain and anastomotic leak. Conclusions: Restoring gut microbiota after disruptions caused by surgery may accelerate local healing processes, attenuate systemic inflammation, and may thus prove beneficial to certain populations.

Gut Microbiota Patterns Predicting Long-Term Weight Loss Success in Individuals with Obesity Undergoing Nonsurgical Therapy

Background: The long-term success of nonsurgical weight reduction programs is variable; thus, predictors of outcome are of major interest. We hypothesized that the intestinal microbiota known to be linked with diet and obesity contain such predictive elements. Methods: Metagenome analysis by shotgun sequencing of stool DNA was performed in a cohort of 15 adults with obesity (mean body mass index 43.1 kg/m²) who underwent a one-year multidisciplinary weight loss program and another year of follow-up. Eight individuals were persistently successful (mean relative weight loss 18.2%), and seven individuals were not successful (0.2%). The relationship between relative abundancies of bacterial genera/species and changes in relative weight loss or body mass index was studied using three different statistical modeling methods. Results: When combining the predictor variables selected by the applied statistical modeling, we identified seven bacterial genera and eight bacterial species as candidates for predicting success of weight loss. By classification of relative weight-loss predictions for each patient using 2–5 term models, 13 or 14 out of 15 individuals were predicted correctly. Conclusions: Our data strongly suggest that gut microbiota patterns allow individual prediction of long-term weight loss success. Prediction accuracy seems to be high but needs confirmation by larger prospective trials.

Ultrasound-guided percutaneous central venous access in a neonatal porcine model

Percutaneous catheterization is currently utilized for central venous access in adult and adolescent porcine models; however, neonatal models require a cut down to gain venous access. This approach requires general anesthesia and can result in systemic inflammation, which can confound studies investigating other inflammatory triggers. Here we present the first successful series of percutaneous, ultrasound-guided, durable central venous access in newborn piglets weighing 1 kg with a novel method of tunneling the catheter subcutaneously using a needle. Catheters (3-5 Fr, single- or double-lumen) were successfully placed in the right jugular vein of eight piglets weighing 1.3 ± 0.4 kg (mean ± standard deviation) with an average duration of catheter patency of 4.5 ± 2.1 days. There were no adverse events from catheter placement, though one catheter was inadvertently removed. This technique is a safe, minimally invasive method for obtaining secure central venous access in a neonatal porcine model.

Dietary κ-carrageenan facilitates gut microbiota-mediated intestinal inflammation

The inflammatory effects of carrageenan (CGN), a ubiquitous food additive, remains controversial. Gut microbiota and intestinal homeostasis may be a breakthrough in resolving this controversy. Here we show that, κ-CGN did not cause significant inflammatory symptoms, but it did cause reduced bacteria-derived short-chain fatty acids (SCFAs) and decreased thickness of the mucus layer by altering microbiota composition. Administration of the pathogenic bacterium Citrobacter rodentium, further aggravated the inflammation and mucosal damage in the presence of κ-CGN. Mucus layer degradation and altered SCFA levels could be reproduced by fecal transplantation from κ-CGN-fed mice, but not from germ-free κ-CGN-fed mice. These symptoms could be partially repaired by administering probiotics. Our results suggest that κ-CGN may not be directly inflammatory, but it creates an environment that favors inflammation by perturbation of gut microbiota composition and then facilitates expansion of pathogens, and this effect may be partially reversed by the introduction of probiotics.

The Effect of the Nutraceutical "MICODIGEST 2.0" on the Colorectal Cancer Surgery With Curative Intent Complications Rate: A Study Protocol for a Placebo-Controlled Double-blind Randomized Clinical Trial (Preprint)

Background

Most colorectal cancer patients diagnosed are candidates for surgical resection with curative intent, although colorectal surgery is associated with some complications that could be life-threatening. Antibiotic prophylaxis is commonly used for the prevention of infectious postoperative complications. However, this intervention can change the composition of intestinal microbiota and promote adverse inflammatory outcomes in colorectal cancer patients. The combination of different fungal extracts could be beneficial because of their role in gut microbiota modulation and their anti-inflammatory activity.

Objective

Based on this hypothesis, we have designed a double-bind, randomized clinical trial to evaluate the effect of the nutraceutical fungal extract Micodigest 2.0 on complications of surgery for colorectal cancer resection.

Methods

Colorectal cancer candidates for surgery will be considered for inclusion in the study. After evaluation by the multidisciplinary tumor board, patients who meet selection criteria will be screened, stratified according to tumor location, and randomly allocated to be treated with Micodigest 2.0 or placebo. Treatment will be continued until admission for surgery (4-6 weeks). Participants will undergo a medical and clinical evaluation including baseline and preadmission quality of life, microbiome composition, inflammatory and nutritional status, adverse events, and adherence assessments. The main end point of the study is the surgery complication rate. We will evaluate complications using the Clavien-Dindo classification. It will be necessary to recruit 144 patients to find a relevant clinical difference. We will also evaluate the effect of the nutraceutical on microbiome composition, inflammatory response, nutritional status, and quality of life, as well as the effect of these variables on surgical complications.

Results

This study was funded in 2020 by the Center for Industrial Technology Development. Recruitment began in September 2021 and is expected to be completed in September 2022. Data will be analyzed and the results will be disseminated in 2023.

Conclusions

The results of this protocol study could help to reduce surgery complications in patients with colorectal cancer using the new treatment Micodigest. This study could also identify new features associated with colorectal surgery complications. In summary, this study trial could improve the management of colorectal cancer patients.

Trial Registration

Clinical Trials.gov NCT04821258; https://clinicaltrials.gov/ct2/show/NCT04821258

International Registered Report Identifier (IRRID)

DERR1-10.2196/34292

Nutritional Interventions Targeting Gut Microbiota during Cancer Therapies

The gut microbiome is increasingly being recognized for its influence on intestinal and extra-intestinal disorders such as cancer. Today, diet is the most studied environmental modulator of gut microbiota, capable of altering or improving it in terms of richness and diversity. Recent evidence from several preclinical and clinical trials suggested that gut microbiota composition could modulate cancer therapies (toxicities, treatment responses) and vice versa. This review highlights the latest research on the bidirectional associations between gut microbiota and cancer. We also dissect the role of gut microbiota during cancer therapies in terms of toxicity and treatment response and, in turn, how cancer therapies could impact gut microbiota composition and functions. In this context, we summarize the state-of-the-art research regarding the role of various nutritional interventions-prebiotics, dietary strategies, and dietary restrictions-as cutting-edge possibilities to modulate gut microbiota during cancer therapies.

Effect of dietary crude protein level on growth performance, blood characteristics, and indicators of intestinal health in weanling pigs

An experiment was conducted to test the hypothesis that reducing crude protein (CP) in starter diets for pigs reduces post-weaning diarrhea and improves intestinal health. In total, 180 weanling pigs were allotted to 3 diets containing 22, 19, or 16% CP. Fecal scores were visually assessed every other day. Blood samples were collected from 1 pig per pen on days 1, 6, 13, 20, and 27, and 1 pig per pen was euthanized on day 12. Results indicated that reducing dietary CP reduced (P < 0.01) overall average daily gain, gain to feed ratio, final body weight, and fecal scores of pigs. Pigs fed the 16% CP diet had reduced (P < 0.01) serum albumin compared with pigs fed other diets. Blood urea nitrogen, haptoglobin, interleukin-1β, and interleukin-6 concentrations in serum were greatest (P < 0.01) on day 13, whereas tumor necrosis factor-α and interleukin-10 concentrations were greatest (P < 0.01) on day 6. Villus height in the jejunum increased (P < 0.05) and crypt depth in the ileum was reduced (P < 0.01) if the 19% CP diet was fed to pigs compared with the 22% CP diet. A reduction (P < 0.05) in mRNA abundance of interferon-γ, chemokine ligand 10, occludin, trefoil factor-2, trefoil factor-3, and mucin 2 was observed when pigs were fed diets with 16% CP. In conclusion, reducing CP in diets for weanling pigs reduces fecal score and expression of genes associated with inflammation.

Intestinal Microbiota in Colorectal Cancer Surgery

The intestinal microbiota consists of numerous microbial species that collectively interact with the host, playing a crucial role in health and disease. Colorectal cancer is well-known to be related to dysbiotic alterations in intestinal microbiota. It is evident that the microbiota is significantly affected by colorectal surgery in combination with the various perioperative interventions, mainly mechanical bowel preparation and antibiotic prophylaxis. The altered postoperative composition of intestinal microbiota could lead to an enhanced virulence, proliferation of pathogens, and diminishment of beneficial microorganisms resulting in severe complications including anastomotic leakage and surgical site infections. Moreover, the intestinal microbiota could be utilized as a possible biomarker in predicting long-term outcomes after surgical CRC treatment. Understanding the underlying mechanisms of these interactions will further support the establishment of genomic mapping of intestinal microbiota in the management of patients undergoing CRC surgery.

Pathomechanisms of Non-Traumatic Acute Brain Injury in Critically Ill Patients

Delirium, an acute alteration in mental status characterized by confusion, inattention and a fluctuating level of arousal, is a common problem in critically ill patients. Delirium prolongs hospital stay and is associated with higher mortality. The pathophysiology of delirium has not been fully elucidated. Neuroinflammation and neurotransmitter imbalance seem to be the most important factors for delirium development. In this review, we present the most important pathomechanisms of delirium in critically ill patients, such as neuroinflammation, neurotransmitter imbalance, hypoxia and hyperoxia, tryptophan pathway disorders, and gut microbiota imbalance. A thorough understanding of delirium pathomechanisms is essential for effective prevention and treatment of this underestimated pathology in critically ill patients.

Gut Mucosal and Fecal Microbiota Profiling Combined to Intestinal Immune System in Neonates Affected by Intestinal Ischemic Injuries

Background and Purpose: Early life microbiota plays a crucial role in human health by acting as a barrier from pathogens' invasion and maintaining the intestinal immune homoeostasis. Altered fecal microbiota (FM) ecology was reported in newborns affected by intestinal ischemia. Our purpose was to describe, in these patients, the FM, the mucosal microbiota (MM) and the mucosal immunity.

Methods: Fourteen newborns underwent intestinal resection because of intestinal ischemia. FM and MM were determined through targeted-metagenomics, diversity assignment and Kruskal-Wallis analyses of Operational taxonomic units (OTUs). The mucosal immune cells were analyzed through cytofluorimetry.

Results and Conclusion: Based on the severity intestinal injueris we identified two groups: extensive (EII) and focal intestinal ischemia (FII). FM and MM varied in EII and FII groups, showing in the EII group the predominance of Proteobacteria and Enterobacteriaceae and the reduction of Bacteroidetes and Verrucomicrobia for both microbiota. The MM was characterized by a statistically significant reduction of Bacteroides, Lachnospiraceae and Ruminococcaceae and by a higher diversity in the EII compared to FII group. FM showed a prevalence of Proteobacteria, while the Shannon index was lower in the EII compared to FII group. An overall increment in B- and T-lymphocytes and Natural killer (NK) T-like cells was found for EII mucosal samples associated to an increment of TNF-α and INF-γ expressing cells, compared to FII group. FM and MM carry specific signatures of intestinal ischemic lesions. Further research may be crucial to address the role of specific taxa in EII, expecially with reference to inflammation grade and ischemia extension.

Long-term outcomes of very low birth weight infants with spontaneous intestinal perforation: A retrospective case-matched cohort study

BACKGROUND

Spontaneous intestinal perforation (SIP) is an intestinal complication that occurs in very ill preterms. We investigated whether SIP survivors have worse neurodevelopmental and gastrointestinal outcomes and a poorer quality of life than controls.

METHODS

A retrospective case-matched cohort study was performed involving infants treated for SIP in a NICU between August 1994 and April 2014. Controls and SIP patients were matched to gestational age, gender, and birth period. Medical records were reviewed. Telephone surveys were conducted to evaluate the medical condition, quality of life (PedsQL™ 4.0), neuropsychiatric and gastrointestinal outcome. McNemar's and Wilcoxon tests were performed, and generalized linear models were computed.

RESULTS

Forty-nine SIP patients were included. The percentages of children with multiple disabilities (40% vs. 17%, OR = 3.3) and requiring physiotherapy (86% vs. 60%, OR = 4.77) were higher in the SIP group than in the control group. Intraventricular hemorrhage (IVH) led to a worse neurodevelopmental outcome regardless of SIP (OR = 8.79 for disability), and female gender was a protective factor against disability (OR = 0.06). Reported quality of life and gastrointestinal comorbidities did not differ between the two groups.

CONCLUSION

SIP survivors tend to be at risk of multiple disabilities. IVH and female gender influence the neurodevelopmental outcome regardless of SIP.

LEVELS OF EVIDENCE

Level III: case-control study.

Current evidence on the relation between gut microbiota and intestinal anastomotic leak in colorectal surgery

BACKGROUND

Anastomotic leak (AL) is a major complication in colorectal surgery. It worsens morbidity, mortality and oncological outcomes in colorectal cancer. Some evidence suggests a potential effect of the intestinal microbiome on wound healing. This review aims to provide a comprehensive review on historical and current evidence regarding the relation between the gastrointestinal microbiota and AL in colorectal surgery, and the potential microbiota-modifying effect of some perioperative commonly used measures.

DATA SOURCES

A comprehensive search was conducted in Pubmed, Medline and Embase for historical and current clinical and animal studies addressing perioperative intestinal microbiota evaluation, intestinal healing and AL.

CONCLUSIONS

Evidence on microbes' role in AL is mainly derived from animal experiments. The microbiota's composition and implications are poorly understood in surgical patients. Elaborate microbiota sequencing is required in colorectal surgery to identify potentially beneficial microbial profiles that could lead to specific perioperative microbiome-altering measures and improve surgical and oncological outcomes.

Abnormal composition of gut microbiota contributes to delirium-like behaviors after abdominal surgery in mice

Aims

Anesthesia and surgery can cause delirium‐like symptoms postoperatively. Increasing evidence suggests that gut microbiota is a physiological regulator of the brain. Herein, we investigated whether gut microbiota plays a role in postoperative delirium (POD).

Methods

Mice were separated into non‐POD and POD phenotypes after abdominal surgery by applying hierarchical clustering analysis to behavioral tests. Fecal samples were collected, and 16S ribosomal RNA gene sequencing was performed to detect differences in gut microbiota composition among sham, non‐POD, and POD mice. Fecal bacteria from non‐POD and POD mice were transplanted into antibiotics‐induced pseudo‐germ‐free mice to investigate the effects on behaviors.

Results

α‐diversity and β‐diversity indicated differences in gut microbiota composition between the non‐POD and POD mice. At the phylum level, the non‐POD mice had significantly higher levels of Tenericutes, which were not detected in the POD mice. At the class level, levels of Gammaproteobacteria were higher in the POD mice, whereas the non‐POD mice had significantly higher levels of Mollicutes, which were not detected in the POD mice. A total of 20 gut bacteria differed significantly between the POD and non‐POD mice. Interestingly, the pseudo‐germ‐free mice showed abnormal behaviors prior to transplant. The pseudo‐germ‐free mice that received fecal bacteria transplants from non‐POD mice but not from POD mice showed improvements in behaviors.

Conclusions

Abnormal gut microbiota composition after abdominal surgery may contribute to the development of POD. A therapeutic strategy that targets gut microbiota could provide a novel alterative for POD treatment.

Dietary fiber sources and non-starch polysaccharide-degrading enzymes modify mucin expression and the immune profile of the swine ileum

Due to their complex chemical and physical properties, the effects and mechanisms of action of natural sources of dietary fiber on the intestine are unclear. Pigs are commonly fed high-fiber diets to reduce production costs and non-starch polysaccharide (NSP)-degrading enzymes have been used to increase fiber digestibility. We evaluated the expression of mucin 2 (MUC2), presence of goblet cells, and ileal immune profile of pigs housed individually for 28 days and fed either a low fiber diet based on corn-soybean meal (CSB, n = 9), or two high fiber diets formulated adding 40% corn distillers' dried grains with solubles (DDGS, n = 9) or 30% wheat middlings (WM, n = 9) to CSB-based diet. Pigs were also fed those diets supplemented with a NSP enzymes mix (E) of xylanase, β-glucanase, mannanase, and galactosidase (n = 8, 10, and 9 for CSB+E, DDGS+E and WM+E, respectively). Feeding DDGS and WM diets increased ileal MUC2 expression compared with CSB diet, and this effect was reversed by the addition of enzymes. There were no differences in abundance of goblet cells among treatments. In general, enzyme supplementation increased gene expression and concentrations of IL-1β, and reduced the concentrations of IL-4, IL-17A and IL-11. The effects of diet-induced cytokines on modulating intestinal MUC2 were assessed in vitro by treating mouse and swine enteroids with 1 ng/ml of IL-4 and IL-1β. In accordance with previous studies, treatment with Il-4 induced Muc2 and expansion of goblet cells in mouse enteroids. However, swine enteroids did not change MUC2 expression or number of goblet cells when treated with IL-4 or IL-1β. Our results suggest that mucin and immune profile are regulated by diet in the swine intestine, but by mechanisms different to mouse, emphasizing the need for using appropriate models to study responses to dietary fiber in swine.

Pharmacomicrobiomics: exploiting the drug-microbiota interactions in anticancer therapies

Cancer is a major health burden worldwide, and despite continuous advances in medical therapies, resistance to standard drugs and adverse effects still represent an important cause of therapeutic failure. There is a growing evidence that gut bacteria can affect the response to chemo- and immunotherapeutic drugs by modulating either efficacy or toxicity. Moreover, intratumor bacteria have been shown to modulate chemotherapy response. At the same time, anticancer treatments themselves significantly affect the microbiota composition, thus disrupting homeostasis and exacerbating discomfort to the patient. Here, we review the existing knowledge concerning the role of the microbiota in mediating chemo- and immunotherapy efficacy and toxicity and the ability of these therapeutic options to trigger dysbiotic condition contributing to the severity of side effects. In addition, we discuss the use of probiotics, prebiotics, synbiotics, postbiotics, and antibiotics as emerging strategies for manipulating the microbiota in order to improve therapeutic outcome or at least ensure patients a better quality of life all along of anticancer treatments.

Positive Glucose Breath Tests in Patients with Hysterectomy, Gastrectomy, and Cholecystectomy

Background/Aims

This study aimed to investigate the prevalence and characteristics of small intestinal bacterial overgrowth (SIBO) in patients undergoing abdominal surgeries, such as gastrectomy, cholecystectomy, and hysterectomy.

Methods

One hundred seventy-one patients with surgery (50 hysterectomy, 14 gastrectomy, and 107 cholecystectomy), 665 patients with functional gastrointestinal disease (FGID) and 30 healthy controls undergoing a hydrogen (H₂)-methane (CH₄) glucose breath test (GBT) were reviewed.

Results

GBT positivity (+) was significantly different among the surgical patients (43.9%), FGID patients (31.9%), and controls (13.3%) (p<0.01). With respect to the patients, 65 (38.0%), four (2.3%), and six (3.5%) surgical patients and 150 (22.6%), 30 (4.5%), and 32 (4.8%) FGID patients were in the GBT (H₂)+, (CH₄)+ and (mixed)+ groups, respectively (p<0.01). The gastrectomy group had a significantly increased preference in GBT+ (71.4% vs 42.0% or 41.1%, respectively) and GBT (H₂)+ (64.3% vs 32.0% or 37.4%, respectively) compared with the hysterectomy or cholecystectomy groups (p<0.01). During GBT, the total H₂ was significantly increased in the gastrectomy group compared with the other groups.

Conclusions

SIBO producing H₂ is common in abdominal surgical patients. Different features for GBT+ may be a result of the types of abdominal surgery.

Salivary microbiome of an urban Indian cohort and patterns linked to subclinical inflammation

OBJECTIVE

To profile salivary microbiomes of an urban-living, healthy Indian cohort and explore associations with proinflammatory status.

METHODS

Fifty-one clinically healthy Indian subjects' salivary microbiomes were analyzed using 16S rRNA Illumina MiSeq sequencing. Community distribution was compared with salivary data from the Human Microbiome Project (HMP). Indian subjects were clustered using microbiome-based "partitioning along medoids" (PAM), and relationships of interleukin-1 beta levels with community composition were analyzed.

RESULTS

Indian subjects presented higher phylogenetic diversity than HMP. Several taxa associated with traditional societies gut microbiomes (Bacteroidales, Paraprevotellaceae, and Spirochaetaceae) were raised. Bifidobacteriaceae and Lactobacillaceae were approximately fourfold greater. A PAM cluster enriched in several Proteobacteria, Actinobacteria, and Bacilli taxa and having almost twofold higher Prevotella to Bacteroides ratio showed significant overrepresentation of subjects within the highest quartile of salivary interleukin-1 beta levels. Abiotrophia, Anaerobacillus, Micrococcus, Aggregatibacter, Halomonas, Propionivivrio, Paracoccus, Mannhemia, unclassified Bradyrhizobiaceae, and Caulobacteraceae were each significant indicators of presence in the highest interleukin-1 beta quartile. 2 OTUs representing Lactobacillus fermentum and Cardiobacterium hominis significantly correlated with interleukin-1 beta levels.

CONCLUSION

The salivary microbiome of this urban-dwelling Indian cohort differed significantly from that of a well-studied Western cohort. Specific community patterns were putatively associated with subclinical inflammation levels.

Risk of failure in pediatric ventriculoperitoneal shunts placed after abdominal surgery

OBJECTIVE Experience has led us to suspect an association between shunt malfunction and recent abdominal surgery, yet information about this potential relationship has not been explored in the literature. The authors compared shunt survival in patients who underwent abdominal surgery to shunt survival in our general pediatric shunt population to determine whether such a relationship exists. METHODS The authors performed a retrospective review of all cases in which pediatric patients underwent ventriculoperitoneal shunt operations at their institution during a 7-year period. Survival time in shunt operations that followed abdominal surgery was compared with survival time of shunt operations in patients with no history of abdominal surgery. Univariate and multivariate analyses were used to identify factors associated with failure. RESULTS A total of 141 patients who underwent 468 shunt operations during the period of study were included; 107 of these 141 patients had no history of abdominal surgery and 34 had undergone a shunt operation after abdominal surgery. Shunt surgery performed more than 2 weeks after abdominal surgery was not associated with time to shunt failure (p = 0.86). Shunt surgery performed within 2 weeks after abdominal surgery was associated with time to failure (adjusted HR 3.6, 95% CI 1.3-9.6). CONCLUSIONS Undergoing shunt surgery shortly after abdominal surgery appears to be associated with shorter shunt survival. When possible, some patients may benefit from shunt placement utilizing alternative termini.

Unravelling the metabolic impact of SBS-associated microbial dysbiosis: Insights from the piglet short bowel syndrome model

Liver disease is a major source of morbidity and mortality in children with short bowel syndrome (SBS). SBS-associated microbial dysbiosis has recently been implicated in the development of SBS-associated liver disease (SBS-ALD), however the pathological implications of this association have not been explored. In this study high-throughput sequencing of colonic content from the well-validated piglet SBS-ALD model was examined to determine alterations in microbial communities, and concurrent metabolic alterations identified in urine samples via targeted mass spectrometry approaches (GC-MS, LC-MS, FIA-MS) further uncovered impacts of microbial disturbance on metabolic outcomes in SBS-ALD. Multi-variate analyses were performed to elucidate contributing SBS-ALD microbe and metabolite panels and to identify microbe-metabolite interactions. A unique SBS-ALD microbe panel was clearest at the genus level, with discriminating bacteria predominantly from the Firmicutes and Bacteroidetes phyla. The SBS-ALD metabolome included important alterations in the microbial metabolism of amino acids and the mitochondrial metabolism of branched chain amino acids. Correlation analysis defined microbe-metabolite clustering patterns unique to SBS-ALD and identified a metabolite panel that correlates with dysbiosis of the gut microbiome in SBS.

Short bowel syndrome (SBS)-associated alterations within the gut-liver axis evolve early and persist long-term in the piglet model of short bowel syndrome

BACKGROUND AND AIM

Short bowel syndrome (SBS) is primarily characterized by malabsorption and malnutrition, resulting from loss of intestinal absorptive area following massive small bowel resection (SBR). Bile acids and the gut microbiota are functionally linked within the gut-liver axis; however, SBS-associated disturbances within the gut-liver axis remain largely unexplored. The aim of this study was to characterize the evolution of bile acid alterations within the gut-liver axis at both short-term and long-term time points and to relate these changes to alterations in colonic bacterial composition.

METHODS

Four-week-old piglets were assigned to 75% SBR, sham-operation or non-operation control groups. High throughput sequencing was employed to determine bacterial abundance in colonic content and ultra-performance liquid chromatography used to determine the bile acid concentration of gall bladder, portal serum, and fecal samples.

RESULTS

Bile acid complexity and relative abundance are altered in the SBS piglet model at two weeks post-SBR, and these changes persisted at six weeks post-SBR. Our examination of the microbial profile revealed an early and persistent loss in bacteria belonging to the Clostridiales order.

CONCLUSIONS

This study provides evidence of an early and persistent disturbance of the bile acid profile throughout the entero-hepatic circulation with an increase in the proportion of primary bile acids and a decrease in secondary bile acids following SBR. These changes were associated with a loss of bacteria belonging to the Clostridiales order consistent with a disturbance in the bile-microbial axis following SBR.

Gut microbiome, surgical complications and probiotics

The trigger for infectious complications in patients following major abdominal operations is classically attributed to endogenous enteral bacterial translocation, due to the critical condition of the gut. Today, extensive gut microbiome analysis has enabled us to understand that almost all "evidence-based" surgical or medical intervention (antibiotics, bowel preparation, opioids, deprivation of nutrition), in addition to stress-released hormones, could affect the relative abundance and diversity of the enteral microbiome, allowing harmful bacteria to proliferate in the place of depressed beneficial species. Furthermore, these bacteria, after tight sensing of host stress and its consequent humoral alterations, can and do switch their virulence accordingly, towards invasion of the host. Probiotics are the exogenously given, beneficial clusters of live bacteria that, upon digestion, seem to succeed in partially restoring the distorted microbial diversity, thus reducing the infectious complications occurring in surgical and critically ill patients. This review presents the latest data on the interrelationship between the gut microbiome and the occurrence of complications after colon surgery, and the efficacy of probiotics as therapeutic instruments for changing the bacterial imbalance.

The role of the microbiota in surgical recovery

PURPOSE OF REVIEW

The purpose of this review is to highlight new research findings in the complex bidirectional crosstalk that occurs between the intestinal microbiome and the host immune system in the context of surgical recovery and outcomes.

RECENT FINDINGS

Significant evidence has been generated emphasizing the central role of the intestinal microbiome on surgical outcomes such as wound healing, surgical site infections and anastomotic leak. Current preventive strategies, including the use of some parenteral antibiotics, may actually exacerbate the problem by selecting for drug-resistant pathogens.

SUMMARY

A delicate balance exists between the human host and its microbial counterparts that is directly related to postsurgical healing. This balance can be easily altered in favor of the pathogen through perioperative and surgical interventions leading to intestinal dysbiosis and loss of colonization resistance. Current strategies to prevent infectious complications with the escalating use of broader and more powerful antibiotics are not an evolutionarily stable strategy. A more complete understanding of the ecological and molecular interactions of the host with its microbiome is necessary to uncover new therapeutic strategies that preserve the composition and function of the intestinal microbiome and constrain virulent pathogens through the course of surgical injury.

Dietary fucoidan modulates the gut microbiota in mice by increasing the abundance ofLactobacillusandRuminococcaceae

This study provides a new insight into the well-recognized beneficial effects of dietary fucoidan by demonstrating its positive modulations on gut microbiota.