Gastrointestinal disorders of the critically ill. Bacterial translocation in the gut

Somatostatin peptides prevent increased human colonic epithelial permeability induced by hypoxia

Mesenteric ischemia increases gut permeability and bacterial translocation. In human colon, chemical hypoxia induced by 2,4-dinitrophenol (DNP) activates basolateral intermediate conductance K+ (IK) channels (designated KCa3.1 or KCNN4) and increases paracellular shunt conductance/permeability (GS), but whether this leads to increased macromolecule permeability is unclear. Somatostatin (SOM) inhibits IK channels and prevents hypoxia-induced increases in GS. Thus, we examined whether octreotide (OCT), a synthetic SOM analog, prevents hypoxia-induced increases GS in human colon and hypoxia-induced increases in total epithelial conductance (GT) and permeability to FITC-dextran 4000 (FITC) in rat colon. The effects of serosal SOM and OCT on increases in GS induced by 100 µM DNP were compared in isolated human colon. The effects of OCT on DNP-induced increases in GT and transepithelial FITC movement were evaluated in isolated rat distal colon. GS in DNP-treated human colon was 52% greater than in controls (P = 0.003). GS was similar when 2 µM SOM was added after or before DNP treatment, in both cases being less (P < 0.05) than with DNP alone. OCT (0.2 µM) was equally effective preventing hypoxia-induced increases in GS, whether added after or before DNP treatment. In rat distal colon, DNP significantly increased GT by 18% (P = 0.016) and mucosa-to-serosa FITC movement by 43% (P = 0.01), and 0.2 µM OCT pretreatment completely prevented these changes. We conclude that OCT prevents hypoxia-induced increases in paracellular/macromolecule permeability and speculate that it may limit ischemia-induced gut hyperpermeability during abdominal surgery, thereby reducing bacterial/bacterial toxin translocation and sepsis.NEW & NOTEWORTHY Somatostatin (SOM, 2 µM) and octreotide (OCT, 0.2 µM, a long-acting synthetic analog of SOM) were equally effective in preventing chemical hypoxia-induced increases in paracellular shunt permeability/conductance in isolated human colon. In rat distal colon, chemical hypoxia significantly increased total epithelial conductance and transepithelial movement of FITC-dextran 4000, changes completely prevented by 0.2 µM OCT. OCT may prevent or limit gut ischemia during abdominal surgery, thereby decreasing the risk of bacterial/bacterial toxin translocation and sepsis.

Ventilatory pressure parameters impact the association between acute gastrointestinal injury and all-cause mortality in mechanically ventilated patients

Acute gastrointestinal injury (AGI) is common in mechanically ventilated (MV) patients, but the potential association between ventilatory pressure parameters and AGI grade and their impact on mortality remains unclear. This study aimed to explore the association between ventilatory pressure parameters and AGI grade, and their interaction on all-cause mortality in MV patients. This study was a secondary analysis of a multicenter, prospective, observational study that enrolled adult patients with an expected duration of mechanical ventilation ≥ 48 h from 14 general intensive care units in Zhejiang Province between March and August 2014. The AGI grade was assessed daily on the basis of gastrointestinal symptoms, intra-abdominal pressures, and feeding intolerance in the first week of admission to the ICU. This study included 331 patients (69.2% men; mean age, 64.6 ± 18.9 years). Multivariate regression analysis showed that plateau pressure (Pplat) (OR 1.044, 95% CI 1.009-1.081, P = 0.013), serum creatinine (OR 1.003, 95% CI 1.001-1.006, P = 0.042) and APACHE II score (OR 1.035, 95% CI 1.021-1.072, P = 0.045) were independently associated with global AGI grade III/IV within 7 days of ICU admission. Moreover, global AGI grade (HR 2.228, 95% CI 1.561-3.182, P < 0.001), serum creatinine (HR 1.002, 95% CI 1.001-1.003, P = 0.012) and APACHE II score (HR 1.039, 95% CI 1.015-1.063, P = 0.001) were independently associated with 60-day mortality. In addition, there were significant (Pint ≤ 0.028) interactions of Pplat and DP with AGI grade in relation to 60-days mortality, whereas no interaction (Pint = 0.061) between PEEP and AGI grade on 60-days mortality was observed. In the presence of Pplat ≥ 19 cmH2O, the patients with AGI grade III/IV had 60-day mortality rate of 72.2%, significantly higher than those with AGI grade I/II (48.7%, P = 0.018), whereas there were no significant differences (27.9% vs. 33.7%, P = 0.39) in 60-days mortality between AGI grade I/II and III/IV among the patients with Pplat < 19 cmH2O. In comparison with Pplat, DP had a similar interaction (Pint = 0.028) with AGI grade on 60-day mortality. Ventilatory pressure parameters (Pplat and DP) are independent risk factors of AGI grade III/IV. Pplat and DP interact with AGI grade on 60-days mortality, highlighting the importance of optimizing ventilatory pressure parameters to improve gastrointestinal function and survival outcomes of MV patients.Trial registration: ChiCTR-OCS-13003824.

Dynamic changes in the migratory microbial components of colon tissue during different periods of sepsis in an LPS-induced rat model

Previous studies have shown that bacterial translocation may play an important role in worsening gastrointestinal injury during sepsis. However, the dynamics of specific microbiota components in intestinal tissues at different sepsis stages remain unclear. Rats receiving intraperitoneal lipopolysaccharide (LPS) were sacrificed at 12 h and 48 h post-injection. Routine blood, serum cytokines, and microbiota in colon tissue, colonic contents, and lung tissue at different time points were assessed. Migratory microbial components in colonic tissue at 12 h and 48 h post-LPS were identified using source tracking, characteristic component identification, and abundance difference analyses. Colonic tissue microbiota changed dynamically over time after LPS injection, involving translocation of microbial components from colon contents and lung tissue at different time points. Bacteria migrating to colon tissue at 12 h sepsis were mainly from colonic contents, while those at 48 h were predominantly from the lung tissue. The migratory microbial components in colon tissue were widely associated with blood indicators and colonizing genus abundance and microbiota functionality in colon tissue. In this study, the temporal dynamics of bacterial translocation from various sources into colon tissues at different sepsis progression stages were characterized for the first time, and the species composition of these migrating microbes was delineated. These bacterial migrants may contribute to the pathophysiological processes in sepsis through direct interactions or indirectly by modulating colonic microbiota community structure and function.

Management of liver disease and portal hypertension in common variable immunodeficiency (CVID)

Patients with common variable immunodeficiency (CVID) frequently develop liver disease and associated complications, which represent an increasingly prevalent unmet medical need. The main hepatic manifestation of CVID is nodular regenerative hyperplasia (NRH), resulting in non-cirrhotic portal hypertension (NCPH). Liver disease is often underdiagnosed, leading to poor outcomes and decreased survival. The increasing numbers of patients with CVID who are diagnosed late with progressive liver disease underscores the importance of appropriate clinical management and treatment of liver complications. At the same time, specific guidelines for the clinical management of CVID-related liver disease are still lacking. Here, we review the epidemiology of CVID-related liver disease, reveal new insights into NRH and NCPH biology and highlight recently uncovered opportunities for NCPH diagnostics in CVID. Finally, we focus on current management of liver disease, portal hypertension and its complications - the key challenge in patients with CVID. Specifically, we review recent data regarding the role of transjugular intrahepatic portosystemic shunt and liver transplantation in clinical management. The role for anticoagulants and immunosuppressants targeting the pathogenesis of NRH will also be discussed. We propose an updated algorithm for the diagnostic work-up and treatment of NCPH in CVID. Finally, we consider future needs and therapeutic opportunities for CVID-related liver disease.

A mechanism by which gut microbiota elevates permeability and inflammation in obese/diabetic mice and human gut

OBJECTIVE

Ample evidence exists for the role of abnormal gut microbiota composition and increased gut permeability ('leaky gut') in chronic inflammation that commonly co-occurs in the gut in both obesity and diabetes, yet the detailed mechanisms involved in this process have remained elusive.

DESIGN

In this study, we substantiate the causal role of the gut microbiota by use of faecal conditioned media along with faecal microbiota transplantation. Using untargeted and comprehensive approaches, we discovered the mechanism by which the obese microbiota instigates gut permeability, inflammation and abnormalities in glucose metabolism.

RESULTS

We demonstrated that the reduced capacity of the microbiota from both obese mice and humans to metabolise ethanolamine results in ethanolamine accumulation in the gut, accounting for induction of intestinal permeability. Elevated ethanolamine increased the expression of microRNA-miR-101a-3p by enhancing ARID3a binding on the miR promoter. Increased miR-101a-3p decreased the stability of zona occludens-1 (Zo1) mRNA, which in turn, weakened intestinal barriers and induced gut permeability, inflammation and abnormalities in glucose metabolism. Importantly, restoring ethanolamine-metabolising activity in gut microbiota using a novel probiotic therapy reduced elevated gut permeability, inflammation and abnormalities in glucose metabolism by correcting the ARID3a/miR-101a/Zo1 axis.

CONCLUSION

Overall, we discovered that the reduced capacity of obese microbiota to metabolise ethanolamine instigates gut permeability, inflammation and glucose metabolic dysfunctions, and restoring ethanolamine-metabolising capacity by a novel probiotic therapy reverses these abnormalities.

TRIAL REGISTRATION NUMBER

NCT02869659 and NCT03269032.

Immunomodulatory Effects of Microcin C7 in Cyclophosphamide-Induced Immunosuppressed Mice

Microcin C7 (McC) as a viable immunomodulator peptide can be a potential solution for pathogenic microbial infection in the post-antibiotic era and has gained substantial attention. This study was designed to evaluate the immunomodulatory activity of Microcin C7 in a cyclophosphamide (CTX)-induced immunodeficient mouse model. We show that Microcin C7 treatment significantly alleviated the CTX-caused body weight loss, improved the feed and water consumption to improve the state of the mice, and elevated the absolute number and proportion of peripheral blood lymphocytes as well as the level of hemoglobulin. We further aim to characterize the phenotypes of the immune function and intestinal health profiles. The results demonstrate that Microcin C7 treatment increased serum levels of immunoglobulin A (IgA), IgG, interleukin 6, and hemolysin, promoted splenic lymphocyte proliferation induced by concanavalin A and LPS, and enhanced the phagocytosis of peritoneal macrophages immunized by sheep red blood cells. Additionally, Microcin C7 treatment decreased levels of diamine oxidase and d-lactate, ameliorated CTX-induced intestinal morphological damage, and increased the levels of zonula occluden 1, occludin, claudin-1, mucin 2, and secretary IgA in the jejunum and colon. Moreover, Microcin C7 administration is sufficient to reverse CTX-induced intestinal microbiota dysbiosis by increasing the number of Lactobacillus and Bifidobacterium, decreasing the number of Escherichia coli in colonic contents. Collectively, our results demonstrate that Microcin C7 may have protective and immunomodulatory functions and could be a potential candidate used in animal feed, functional foods, and immunological regimens..

Potential role of gut microbiota in prostate cancer: immunity, metabolites, pathways of action?

The gut microbiota helps to reveal the relationship between diseases, but the role of gut microbiota in prostate cancer (PCa) is still unclear. Recent studies have found that the composition and abundance of specific gut microbiota are significantly different between PCa and non-PCa, and the gut microbiota may have common and unique characteristics between different diseases. Intestinal microorganisms are affected by various factors and interact with the host in a variety of ways. In the complex interaction model, the regulation of intestinal microbial metabolites and the host immune system is particularly important, and they play a key role in maintaining the ecological balance of intestinal microorganisms and metabolites. However, specific changes in the composition of intestinal microflora may promote intestinal mucosal immune imbalance, leading to the formation of tumors. Therefore, this review analyzes the immune regulation of intestinal flora and the production of metabolites, as well as their effects and mechanisms on tumors, and briefly summarizes that specific intestinal flora can play an indirect role in PCa through their metabolites, genes, immunity, and pharmacology, and directly participate in the occurrence, development, and treatment of tumors through bacterial and toxin translocation. We also discussed markers of high risk PCa for intestinal microbiota screening and the possibility of probiotic ingestion and fecal microbiota transplantation, in order to provide better treatment options for clinic patients. Finally, after summarizing a number of studies, we found that changes in immunity, metabolites.

Unexplained septic shock after colonoscopy with polyethylene glycol preparation in a young adult: A case report

BACKGROUND

Colonoscopy has become a routine physical examination as people’s health awareness has increased. Polyethylene glycol (PEG) is greatly used in bowel preparation before colonoscopy due to its price and safety advantages. Septic shock after colonoscopy with PEG preparation is extremely rare, with only very few cases in critically ill patients. Herein, we describe a case of septic shock in a healthy young adult immediately following colonoscopy with PEG preparation.

CASE SUMMARY

A 33-year-old young adult presented to our hospital for colonoscopy with PEG bowel preparation due to recurrent diarrhea for 7 years. The male's previous physical examination showed no abnormal indicators, and colonoscopy results were normal; however, he exhibited septic shock and markedly elevated white blood cell, C-reactive protein, and procalcitonin levels on the second day after colonoscopy. Immediate resuscitation and intensive care with appropriate antibiotics improved his condition. However, the blood and stool cultures did not detect the pathogen

CONCLUSION

Septic shock after colonoscopy is rare, especially in young adults. The authors considered the possibility of opportunistic infections after PEG bowel preparation, and clinicians should monitor patients for the possibility of such complications

Electroacupuncture in Treatment of Acute Gastrointestinal Injury in Patients with Severe Traumatic Brain Injury: A Multicenter Randomized Controlled Trial

OBJECTIVE

To evaluate whether electroacupuncture (EA) would improve gastrointestinal function and clinical prognosis in patients with severe traumatic brain injury (TBI) complicocted by acute gastrointestinal injury (AGI).

METHODS

This multicenter, single-blind trial included patients with TBI and AGI admitted to 5 Chinese hospitals from September 2018 to December 2019. A total of 500 patients were randomized to the control or acupuncture groups using a random number table, 250 cases in each group. Patients in the control group received conventional treatment, including mannitol, nutritional support, epilepsy and infection prevention, and maintenance of water, electrolytes, and acid-base balance. While patients in the acupuncture group received EA intervention at bilateral Zusanli (ST 36), Shangjuxu (ST 37), Xiajuxu (ST 39), Tianshu (ST 25), and Zhongwan (RN 12) acupoints in addition to the conventional treatment, 30 min per time, twice daily, for 7 d. The primary endpoint was 28-d mortality. The secondary endpoints were serum levels of D-lactic acid (D-lac), diamine oxidase (DAO), lipopolysaccharide (LPS), motilin (MTL) and gastrin (GAS), intra-abdominal pressure (IAP), bowel sounds, abdominal circumference, AGI grade, scores of gastrointestinal failure (GIF), Glasgow Coma Scale (GCS), Acute Physiology and Chronic Health Evaluation (APACHE II), Sequential Organ Failure Assessment (SOFA), and Multiple Organ Dysfunction Syndrome (MODS), mechanical ventilation time, intense care unit (ICU) stay, and the incidence of hospital-acquired pneumonia.

RESULTS

The 28-d mortality in the acupuncture group was lower than that in the control group (22.80% vs. 33.20%, P<0.05). Compared with the control group, the acupuncture group at 7 d showed lower GIF, APACHE II, SOFA, MODS scores, D-lac, DAO, LPS, IAP, and abdominal circumference and higher GCS score, MTL, GAS, and bowel sound frequency (all P<0.05). In addition, the above indices showed simillar changes at 7 d compared with days 1 and 3 (all P<0.05) in the EA group.

CONCLUSION

Early EA can improve gastrointestinal function and clinical prognosis in patients with severe TBI complicated by AGI. (Registration No. ChiCTR2000032276).

Preventing Bacterial Translocation in Patients with Leaky Gut Syndrome: Nutrition and Pharmacological Treatment Options

Leaky gut syndrome is a medical condition characterized by intestinal hyperpermeability. Since the intestinal barrier is one of the essential components maintaining homeostasis along the gastrointestinal tract, loss of its integrity due to changes in bacterial composition, decreased expression levels of tight junction proteins, and increased concentration of pro-inflammatory cytokines may lead to intestinal hyperpermeability followed by the development of gastrointestinal and non-gastrointestinal diseases. Translocation of microorganisms and their toxic metabolites beyond the gastrointestinal tract is one of the fallouts of the leaky gut syndrome. The presence of intestinal bacteria in sterile tissues and distant organs may cause damage due to chronic inflammation and progression of disorders, including inflammatory bowel diseases, liver cirrhosis, and acute pancreatitis. Currently, there are no medical guidelines for the treatment or prevention of bacterial translocation in patients with the leaky gut syndrome; however, several studies suggest that dietary intervention can improve barrier function and restrict bacteria invasion. This review contains current literature data concerning the influence of diet, dietary supplements, probiotics, and drugs on intestinal permeability and bacterial translocation.

Intestinal virome and therapeutic potential of bacteriophages in liver disease

Humans harbour a large quantity of microbes in the intestinal tract and have evolved symbiotic relationships with many of them. However, several specific bacterial pathobionts are associated with liver disease pathogenesis. Although bacteriophages (phages) and eukaryotic viruses (collectively known as "the virome") outnumber bacteria and fungi in the intestine, little is known about the intestinal virome in patients with liver disease. As natural predators of bacteria, phages can precisely edit the bacterial microbiota. Hence, there is interest in using them to target bacterial pathobionts in several diseases, including those of the liver. Herein, we will summarise changes in the faecal virome associated with fatty liver diseases and cirrhosis, and describe the therapeutic potential of phages and potential challenges to their clinical application.

Glucan rich nutrition does not increase gut translocation of beta-glucan

BACKGROUND

(1-3)-b-D-glucan (BDG) is a fungal cell wall component and, in the absence of invasive fungal infection, a novel biomarker for microbial translocation of endogenous fungal products from the gastrointestinal tract into systemic circulation. However, its value as a marker of fungal translocation is limited by a concern that plant BDG-rich food influences blood BDG levels.

METHODS

We conducted a pilot clinical trial to evaluate the impact of a standardised oral BDG challenge on blood BDG levels in participants with and without elevated microbial translocation. We enrolled 14 participants including 8 with HIV infection, 2 with advanced liver cirrhosis, and 4 healthy controls. After obtaining a baseline blood sample, participants received a standardised milkshake containing high levels of BDG followed by serial blood samples up to 8 hours after intake.

RESULTS

The standardised oral BDG challenge approach did not change the blood BDG levels over time in all participants. We found consistently elevated blood BDG levels in one participant with advanced liver cirrhosis and a single person with HIV with a low CD4 count of 201 cells/mm3 .

CONCLUSION

Our findings indicate that BDG blood levels were not influenced by plant origin BDG-rich nutrition in PWH, people with advanced liver cirrhosis, or healthy controls. Future studies are needed to analyse gut mycobiota populations in individuals with elevated blood BDG levels.

Gastrointestinal Symptoms Associated With Unfavorable Prognosis of COVID-19 Patients: A Retrospective Study

Background and Aim: The global pandemic of COVID-19 has posed an enormous threat to the economy and people's lives across various countries. Patients with COVID-19 most commonly present with respiratory symptoms. However, gastrointestinal (GI) symptoms can also occur. We aimed to study the relationship between GI symptoms and disease prognosis in patients with COVID-19. Methods: In a single-center and retrospective cohort study, the outcomes in COVID-19 patients with or without GI symptoms were compared. The propensity score is a conditional probability of having a particular exposure (COVID-19 patients with GI symptoms vs. without GI symptoms) given a set of baseline measured covariates. Survival was estimated using the Kaplan-Meier method, and any differences in survival were evaluated with a stratified log-rank-test. To explore the GI symptoms associated with ARDS, non-invasive ventilator treatment, tracheal intubation, tracheotomy, and CRRT, univariable and multivariable COX regression models were used. Results: Among 1,113 eligible patients, 359 patients with GI symptoms and 718 without GI symptoms had similar propensity scores and were included in the analyses. Patients with GI symptoms, as compared with those without GI symptoms, were associated with a similar risk of death, but with higher risks of ARDS, non-invasive mechanical ventilation in COVID-19 patients, respectively. Conclusions: The presence of GI symptoms was associated with a high risk of ARDS, non-invasive mechanical ventilation and tracheal intubation in patients with COVID-19 but not mortality.

Dietary Bacillus spp. enhanced growth and disease resistance of weaned pigs by modulating intestinal microbiota and systemic immunity

Background

Previous research has shown that dietary supplementation of Bacillus spp. probiotics exerts beneficial effects on animals' growth. However, limited studies have evaluated the efficacy of Bacillus spp. on weaned pigs and their effects on host gut health and microbiome, and systemic immunity using a disease challenge model. The objective of this experiment was to investigate the effects of two Bacillus spp. strains (Bacillus subtilis DSM 32540 and Bacillus pumilus DSM 32539) on growth performance, diarrhea, intestinal health, microbiome, and systemic immunity of weaned pigs experimentally infected with an enterotoxigenic Escherichia coli (ETEC).

Results

Pigs in PRO1 (Bacillus subtilis DSM 32540) had greater (P < 0.05) body weight on d 7 and 14 PI, greater (P < 0.05) ADG from d 0 to 7 and d 7 to 14 PI, compared with pigs in CON (Control). Pigs in PRO1 had milder (P < 0.05) diarrhea on d 2 and 3 PI compared with pigs in CON. However, no differences were observed in growth performance and diarrhea score between PRO2 (Bacillus pumilus DSM 32539) and CON groups. Supplementation of PRO1 decreased (P < 0.05) lymphocyte counts on d 7 and 14 PI, compared with CON. Supplementation of PRO1 and PRO2 both reduced (P < 0.05) total coliforms in mesenteric lymph nodes on d 21 PI. Pigs in PRO2 had greater (P < 0.05) goblet cell number and sulfomucin percentage in duodenal villi and greater (P < 0.05) sialomucin percentage in jejunal villi than pigs in CON. Supplementation of PRO1 up-regulated (P < 0.05) MUC2 gene expression in jejunal mucosa and reduced (P < 0.05) PTGS-2 and IL1B gene expression in ileal mucosa on d 21 PI, compared with CON. Pigs in PRO1 had reduced (P < 0.05) relative abundance of families Lachnospiraceae, Peptostreptococcaceae and Pasteurellaceae in the ileum.

Conclusions

Supplementation of Bacillus subtilis DSM 32540 improved growth performance, alleviated diarrhea severity, enhanced gut health, and reduced systemic inflammation of weaned pigs infected with ETEC F18. Although Bacillus pumilus DSM 32539 was able to alleviate systemic inflammation, it had limited impacts on growth performance and severity of diarrhea of ETEC F18 challenged weaned pigs.

Breakthrough invasive fungal infections: Who is at risk?

The epidemiology of invasive fungal infections (IFIs) in immunocompromised individuals has changed over the last few decades, partially due to the increased use of antifungal agents to prevent IFIs. Although this strategy has resulted in an overall reduction in IFIs, a subset of patients develop breakthrough IFIs with substantial morbidity and mortality in this population. Here, we review the most significant risk factors for breakthrough IFIs in haematology patients, solid organ transplant recipients, and patients in the intensive care unit, focusing particularly on host factors, and highlight areas that require future investigation.

Current Status and Prospects of Spontaneous Peritonitis in Patients with Cirrhosis

Spontaneous bacterial peritonitis (SBP) is a common cirrhotic ascites complication which exacerbates the patient's condition. SBP is caused by gram-negative bacilli and, to a lesser extent, gram-positive cocci. Hospital-acquired infections show higher levels of drug-resistant bacteria. Geographical location influences pathogenic bacteria distribution; therefore, different hospitals in the same country record different bacteria strains. Intestinal changes and a weak immune system in patients with liver cirrhosis lead to bacterial translocation thus causing SBP. Early diagnosis and timely treatment are important in SBP management. When the treatment effect is not effective, other rare pathogens should be explored.

The magnitude of physical exercise-induced hyperthermia is associated with changes in the intestinal permeability and expression of tight junction genes in rats

We investigated whether the magnitude of exercise-induced hyperthermia influences intestinal permeability and tight junction gene expression. Twenty-nine male Wistar rats were divided into four groups: rest at 24 °C and exercise at 13 °C, 24 °C or 31 °C. The exercise consisted of a 90-min treadmill run at 15 m/min, and different ambient temperatures were used to produce distinct levels of exercise-induced hyperthermia. Before the experimental trials, the rats were treated by gavage with diethylenetriaminepentaacetic acid labeled with technetium-99 metastable as a radioactive probe. The rats' core body temperature (T_CORE) was measured by telemetry. Immediately after the trials, the rats were euthanized, and the intestinal permeability was assessed by measuring the radioactivity of blood samples. The mRNA levels of occludin and zonula occludens-1 (ZO-1) genes were determined in duodenum samples. Exercise at 24 °C increased T_CORE to values close to 39 °C, without changing permeability compared with the resting trial at the same environment. Meanwhile, rats' T_CORE exceeded 40 °C during exercise at 31 °C, leading to greater permeability relative to those observed after exercise in the other ambient temperatures (e.g., 0.0037%/g at 31 °C vs. 0.0005%/g at 13 °C; data expressed as medians; p < 0.05). Likewise, the rats exercised at 31 °C exhibited higher mRNA levels of ZO-1 and occludin genes than the rats exercised at 24 °C or 13 °C. The changes in permeability and gene expression were positively and significantly associated with the magnitude of hyperthermia. We conclude that marked hyperthermia caused by exercise in the warmer environment increases intestinal permeability and mRNA levels of tight junction genes.

Preclinical Detection of Non-catheter Related Late-onset Sepsis in Preterm Infants by Fecal Volatile Compounds Analysis: A Prospective, Multi-center Cohort Study

BACKGROUND

Late onset sepsis (LOS) in preterm infants is preceded by fecal volatile organic compound (VOC) alterations, suggesting an etiologic role of gut microbiota in LOS rather than being primarily caused by central venous catheters (CVC). To increase our knowledge about the involvement of the gut microbiota in LOS, we analyzed fecal samples from septic infants without a CVC.

METHODS

In this prospective multicenter study, fecal samples were collected daily from all infants born at ≤30 weeks gestation. Fecal VOC profiles up to 3 days prior to sepsis onset from infants with non-catheter-related LOS were compared with profiles from non-septic controls by means of High-Field Asymmetric Waveform Ion Mobility Spectrometry.

RESULTS

In total, 104 fecal samples were analyzed. Fecal VOC profiles allowed for discrimination between non-catheter-related LOS cases (n = 24) and matched controls (n = 25). Discriminative accuracy increased after focusing on center of origin (area under the curve, sensitivity, specificity; 0.95, 100%, 83%) and after focusing on LOS cases caused by Staphylococcus epidermidis (0.95, 100%, 78%), the most cultured pathogen (n = 11).

CONCLUSIONS

Fecal VOC profiles of preterm LOS infants without a CVC differed from matched controls underlining the increasing notion that aberrations in gut microbiota composition and activity may play a role in LOS etiology.

The correlation between intestinal mucosal lesions and hepatic dysfunction in patients without chronic liver disease

Patients with cirrhosis are known to develop small bowel mucosal lesions. However, the occurrence of mucosal lesions in patients with abnormal liver function test results in the absence of chronic liver disease has not been fully evaluated. This study aims to examine the association between small bowel endoscopic lesions and liver dysfunction in patients without confirmed chronic liver disease.Two hundred ninety six consecutive patients who met the selection criteria underwent capsule endoscopy. The severity of the small intestinal mucosal lesions was evaluated quantitatively using the Lewis scoring system, and hepatic dysfunction was evaluated using an algorithm-based combination scoring system with 8 individual serological markers.Small bowel lesions were observed in 121 patients (40.88%). Hepatic dysfunction was significantly more prevalent in patients with small bowel lesions than in those without lesions (33.1%; 40/121 and 5.7%; 10/175, respectively; P < .001). The mean serum ALT and AST levels were significantly higher in patients with small bowel lesions than in those without lesions (P = .007 and P = .004, respectively). The mean scores for AST to Platelet Ratio Index, Forns Index, S-Index, Fibrosis-4 Index and BARD were significantly higher in patients with small bowel lesions than those without lesions. The Lewis score significantly and positively correlated with the Forns Index (P = .008) and the FIB-4 Index (P = .006).There is a close correlation between small intestinal mucosal lesions and hepatic dysfunction. The severity of hepatic dysfunction is directly proportional to the severity of the small intestinal mucosal lesions in patients without confirmed chronic liver disease.

The Microbiota in Hematologic Malignancies

OPINION STATEMENT

There are approximately 1.2 million new hematologic malignancy cases resulting in ~ 690,000 deaths each year worldwide, and hematologic malignancies remain the most commonly occurring cancer in children. Even though advances in anticancer treatment regimens in recent decades have considerably improved survival rates, their cytotoxic effects and the resulting long-term complications pose a significant burden on the patients and the health care system. Therefore, non-toxic treatment modalities are needed to decrease side effects. The human body is the host to approximately 40 trillion microbes, known as the human microbiota. The large majority of the microbiota is located in the gastrointestinal tract, and is primarily composed of bacteria. The microbiota plays several important physiological roles, ranging from digestive functions to immunological and neural development. Investigating the microbiota in patients with hematologic malignancies has several important implications. The microbiota affects hematopoiesis, and influences the efficacies of chemotherapy and antimicrobial treatments. Determination of the microbiota composition and diversity could be an important part of risk stratification in the future, and may also take part to personalize antimicrobial treatments. Modulation of the microbiota via probiotics or fecal transplant can potentially be involved in reducing side effects of chemotherapy, and eliminating multiple drug resistant strains in patients with hematologic malignancies.

Microbiota changes in a pediatric acute lymphocytic leukemia mouse model

Hematological malignancies are the most common type of pediatric cancers, and acute lymphocytic leukemia (ALL) is the most frequently occurring hematological malignancy during childhood. A major cause of mortality in leukemia is bloodstream infection (BSI). The aim of the current study was to explore the gut microbiota in ALL and its potential functional alterations. High-throughput sequencing was used to characterize the bacterial and fungal microbiota in feces and their predicted functional characteristics in a xenotransplant pediatric ALL mouse model. Our work shows that gut microbiota significantly changes in leukemia, which may result in functional alterations. This study may provide potential therapeutic or preventive strategies of BSI in ALL.

Wheat gluten intake increases the severity of experimental colitis and bacterial translocation by weakening of the proteins of the junctional complex

Gluten is only partially digested by intestinal enzymes and can generate peptides that can alter intestinal permeability, facilitating bacterial translocation, thus affecting the immune system. Few studies addressed the role of diet with gluten in the development of colitis. Therefore, we investigate the effects of wheat gluten-containing diet on the evolution of sodium dextran sulphate (DSS)-induced colitis. Mice were fed a standard diet without (colitis group) or with 4·5 % wheat gluten (colitis + gluten) for 15 d and received DSS solution (1·5 %, w/v) instead of water during the last 7 d. Compared with the colitis group, colitis + gluten mice presented a worse clinical score, a larger extension of colonic injury area, and increased mucosal inflammation. Both intestinal permeability and bacterial translocation were increased, propitiating bacteria migration for peripheral organs. The mechanism by which diet with gluten exacerbates colitis appears to be related to changes in protein production and organisation in adhesion junctions and desmosomes. The protein α-E-catenin was especially reduced in mice fed gluten, which compromised the localisation of E-cadherin and β-catenin proteins, weakening the structure of desmosomes. The epithelial damage caused by gluten included shortening of microvilli, a high number of digestive vacuoles, and changes in the endosome/lysosome system. In conclusion, our results show that wheat gluten-containing diet exacerbates the mucosal damage caused by colitis, reducing intestinal barrier function and increasing bacterial translocation. These effects are related to the induction of weakness and disorganisation of adhesion junctions and desmosomes as well as shortening of microvilli and modification of the endocytic vesicle route.

The Role of Gut-Derived Microbial Antigens on Liver Fibrosis Initiation and Progression

Intestinal dysbiosis has recently become known as an important driver of gastrointestinal and liver disease. It remains poorly understood, however, how gastrointestinal microbes bypass the intestinal mucosa and enter systemic circulation to enact an inflammatory immune response. In the context of chronic liver disease (CLD), insults that drive hepatic inflammation and fibrogenesis (alcohol, fat) can drastically increase intestinal permeability, hence flooding the liver with gut-derived microbiota. Consequently, this may result in exacerbated liver inflammation and fibrosis through activation of liver-resident Kupffer and stellate cells by bacterial, viral, and fungal antigens transported to the liver via the portal vein. This review summarizes the current understanding of microbial translocation in CLD, the cell-specific hepatic response to intestinal antigens, and how this drives the development and progression of hepatic inflammation and fibrosis. Further, we reviewed current and future therapies targeting intestinal permeability and the associated, potentially harmful anti-microbial immune response with respect to their potential in terms of limiting the development and progression of liver fibrosis and end-stage cirrhosis.

Virome-host interactions in intestinal health and disease

The enteric virome consists largely of bacteriophages and prophages related to commensal bacteria. Bacteriophages indirectly affect the host immune system by targeting their associated bacteria; however, studies suggest that bacteriophages also have distinct pathways that enable them to interact directly with the host. Eukaryotic viruses are less abundant than bacteriophages but are more efficient in the stimulation of host immune responses. Acute, permanent, and latent viral infections are detected by different types of pattern recognition receptors and induce host immune responses, including the antiviral type I interferon response. Understanding the complex interplay between commensal microorganisms and the host immune system is a prerequisite to elucidating their role in intestinal diseases.

Bacterial translocation in acute lymphocytic leukemia

Bloodstream infection (BSI) is the major cause of mortality in acute lymphocytic leukemia (ALL). Causative pathogens in BSI originate from the gut microbiota due to an increase in intestinal permeability, a process known as bacterial translocation (BT). The gut microbiota in physiological conditions is controlled by a large number of immune cells as part of the gut-associated lymphoid tissue (GALT).The aim of the current study was to investigate the mechanism of bacterial translocation in leukemia by identifying and characterizing alterations in the GALT in leukemic mouse model. Our studies revealed a severe impairment of the GALT characterized by a loss of lymphatic cells in ALL, which eventually led to BSI. We identified differentially expressed genes in the intraepithelium and the lamina propria, which may contribute to BT and to the impairment of lymphocyte migration.

Natural molecules induce and synergize to boost expression of the human antimicrobial peptide β-defensin-3

Antimicrobial peptides (AMPs) are mucosal defense effectors of the human innate immune response. In the intestine, AMPs are produced and secreted by epithelial cells to protect the host against pathogens and to support homeostasis with commensals. The inducible nature of AMPs suggests that potent inducers could be used to increase their endogenous expression for the prevention or treatment of diseases. Here we aimed at identifying molecules from the natural pharmacopoeia that induce expression of human β-defensin-3 (HBD3), one of the most efficient AMPs, without modifying the production of proinflammatory cytokines. By screening, we identified three molecules isolated from medicinal plants, andrographolide, oridonin, and isoliquiritigenin, which induced HBD3 production in human colonic epithelial cells. This effect was observed without activation of the NF-κB pathway or the expression of associated proinflammatory cytokines. We identified the EGF receptor as the target of these compounds and characterized the downstream-activated MAPK pathways. At the chromatin level, molecules increased phosphorylation of histone H3 on serine S10 and recruitment of the c-Fos, c-Jun, and Elk1 or c-Myc transcription factors at the HBD3 promoter. Interestingly, stimulating cells with a combination of andrographolide and isoliquiritigenin synergistically enhanced HBD3 induction 10-fold more than observed with each molecule alone. Finally, we investigated the molecular basis governing the synergistic effect, confirmed our findings in human colonic primary cells, and demonstrated that synergism increased cellular antimicrobial activity. This work shows the capability of small molecules to achieve induction of epithelial antimicrobial defenses while simultaneously avoiding the deleterious risks of an inflammatory response.

Gut-origin sepsis in the critically ill patient: pathophysiology and treatment

INTRODUCTION

Gut permeability is increased in critically ill patients, and associated with the development of the systemic inflammatory response syndrome and multiple organ dysfunction syndrome (MODS). The pathogenetic link(s) and potential therapies are an area of intense research over the last decades.

METHODS

We thoroughly reviewed the literature on gut-origin sepsis and MODS in critically ill patients, with emphasis on the implicated pathophysiological mechanisms and therapeutic interventions.

FINDINGS

Intestinal barrier failure leading to systemic bacterial translocation associated with MODS was the predominant pathophysiological theory for several years. However, clinical studies with critically ill patients failed to provide the evidence of systemic spread of gut-derived bacteria and/or their products as a cause of MODS. Newer experimental data highlight the role of the mesenteric lymph as a carrier of gut-derived danger-associated molecular patterns (DAMPs) to the lung and the systemic circulation. These substances are recognized by pattern recognition receptor-bearing cells in diverse tissues and promote proinflammatory pathways and the development MODS. Therefore, the gut becomes a pivotal proinflammatory organ, driving the systemic inflammatory response through DAMPs release in mesenteric lymph, without the need for systemic bacterial translocation.

CONCLUSIONS

There is an emerging need for application of sensitive non-invasive and easily measured biomarkers of early intestinal injury (e.g., citrulline, intestinal fatty acid protein, and zonulin) in our everyday clinical practice, guiding the early pharmacological intervention in critically ill patients to restore or prevent intestinal injury and improve their outcomes.

Candida albicans-Induced Epithelial Damage Mediates Translocation through Intestinal Barriers

Life-threatening systemic infections often occur due to the translocation of pathogens across the gut barrier and into the bloodstream. While the microbial and host mechanisms permitting bacterial gut translocation are well characterized, these mechanisms are still unclear for fungal pathogens such as Candida albicans, a leading cause of nosocomial fungal bloodstream infections. In this study, we dissected the cellular mechanisms of translocation of C. albicans across intestinal epithelia in vitro and identified fungal genes associated with this process. We show that fungal translocation is a dynamic process initiated by invasion and followed by cellular damage and loss of epithelial integrity. A screen of >2,000 C. albicans deletion mutants identified genes required for cellular damage of and translocation across enterocytes. Correlation analysis suggests that hypha formation, barrier damage above a minimum threshold level, and a decreased epithelial integrity are required for efficient fungal translocation. Translocation occurs predominantly via a transcellular route, which is associated with fungus-induced necrotic epithelial damage, but not apoptotic cell death. The cytolytic peptide toxin of C. albicans, candidalysin, was found to be essential for damage of enterocytes and was a key factor in subsequent fungal translocation, suggesting that transcellular translocation of C. albicans through intestinal layers is mediated by candidalysin. However, fungal invasion and low-level translocation can also occur via non-transcellular routes in a candidalysin-independent manner. This is the first study showing translocation of a human-pathogenic fungus across the intestinal barrier being mediated by a peptide toxin.IMPORTANCECandida albicans, usually a harmless fungus colonizing human mucosae, can cause lethal bloodstream infections when it manages to translocate across the intestinal epithelium. This can result from antibiotic treatment, immune dysfunction, or intestinal damage (e.g., during surgery). However, fungal processes may also contribute. In this study, we investigated the translocation process of C. albicans using in vitro cell culture models. Translocation occurs as a stepwise process starting with invasion, followed by epithelial damage and loss of epithelial integrity. The ability to secrete candidalysin, a peptide toxin deriving from the hyphal protein Ece1, is key: C. albicans hyphae, secreting candidalysin, take advantage of a necrotic weakened epithelium to translocate through the intestinal layer.

Combined Effectiveness of Honey and Immunonutrition on Bacterial Translocation Secondary to Obstructive Jaundice in Rats: Experimental Study

BACKGROUND Obstructive jaundice is a serious, life-threatening condition that can lead to death as a result of sepsis and multiorgan failure due to bacterial translocation. Treatment should be started as soon as possible after diagnosis. MATERIAL AND METHODS Forty 24-week-old male Sprague Dawley rats, with an average weight of 250 g to 300 g, were included in this study. The rats were randomly placed into five groups, each group consisted of eight rats. The sham group underwent only common bile duct (CBD) dissection and no ligation was performed. CBD ligation was applied to the other groups. After the operation, one CBD group was fed with rat chow only, the others were fed with rat chow supplemented with honey, or immunonutrients, or honey plus immunonutrients. After 10 to 12 days, all rats were sacrificed; blood and tissue samples were collected for biochemical, microbiological, and histopathological evaluation. RESULTS In the groups that were fed with honey and immunonutrients, alanine aminotransferase (ALT) levels were decreased significantly compared to the other groups. Statistically significant differences were detected in terms of bacterial translocation (BT) rates among liver and spleen samples, and laboratory values of serum, except for MLNs of the BDL+HI group, when compared to other groups. We found mean mucosal thickness of ileum samples have been improved notably in the BDL+HI group compared to the other groups, especially compared to the C/BDL group. CONCLUSIONS Immunonutrition applied with honey had immunostimulant effects, decreased BT due to an additive effect, and had positive effects on intestinal mucosa.

Targeting the gut-liver axis in liver disease

The gut-liver axis is widely implicated in the pathogenesis of liver diseases, where it is increasingly the focus of clinical research. Recent studies trialling an array of therapeutic and preventative strategies have yielded promising results. Considering these strategies, the armamentarium for targeting the gut-liver axis will continue to expand. Further clinical trials, translated from our current knowledge of the gut-liver axis, promise an exciting future in liver treatment.

Detection of Sepsis in Preterm Infants by Fecal Volatile Organic Compounds Analysis: A Proof of Principle Study

OBJECTIVES

Several studies associated altered gut microbiota composition in preterm infants with late-onset sepsis (LOS), up to days before clinical onset of sepsis. Microbiota analysis as early diagnostic biomarker is, however, in clinical practice currently not feasible because of logistic aspects and high costs. Therefore, we hypothesized that analysis of fecal volatile organic compounds (VOCs) may serve as noninvasive biomarker to predict LOS at a preclinical stage, because VOC reflect the composition and activity of intestinal microbial communities.

METHODS

In a prospective multicenter study, fecal samples were collected daily from infants with a gestational age of <30 weeks. VOC signatures of fecal samples from infants with LOS, collected up to 5 days before diagnosis, were analyzed by means of an electronic nose technology (Cyranose 320) and compared to matched controls.

RESULTS

Fecal VOC profiles of infants with LOS (n = 36) could be discriminated from controls (n = 40) at 3 days (area under the curve [±95% confidence interval], P value, sensitivity, specificity; 70.2 [52.2-88.3], 0.033, 57.1%, 61.5%), 2 days (77.7 [62.7-92.7], 0.050, 75.0%, 70.8%), and 1 day (70.4 [49.6-91.3], 0.037, 64.3%, 64.3%) before the onset of LOS.

CONCLUSIONS

Fecal VOC profiles of preterm infants with LOS could be discriminated from matched controls, up to 3 days before clinical onset of the disease, underlining the hypothesis that intestinal microbiota may play an etiological role in LOS. Notably, VOC profiling is clinically feasible and the potential of this technique in the early detection of LOS needs to be confirmed in future studies.

Bacterial translocation markers in liver cirrhosis

Bacterial translocation (BT) is an important mechanism in the development of infection in liver cirrhosis. The migration and colonization of bacteria and/or bacterial products from the bowel to mesenteric lymph nodes is a controlled process in healthy persons. Increased intestinal permeability, bacterial overgrowth and defect of gut-associated lymphatic tissue promote impaired BT in cirrhotics. We reviewed the reports on markers used for the evaluation of BT published between 1987 and 2016. We focused on the clinical consequences of BT in cirrhosis, as indicated by the values of the BT markers. Patients with cirrhosis are reported to have elevated levels of surrogate markers associated with BT compared with controls. The most widely used BT parameters are C-reactive protein, procalcitonin, bacterial DNA, endotoxin or lipopolysaccharide, lipopolysaccharide binding protein, calprotectin, and bactericidal/permeability increasing protein. High levels of these factors in serum and/or ascitic fluid in humans may be associated with advanced liver disease, hemodynamic instability, high levels of proinflammatory cytokines, susceptibility to the development of severe or recurrent infections, acute-on-chronic liver failure, hepatic encephalopathy, hepatorenal syndrome and poor prognosis during follow up. In conclusion, high levels of BT markers are associated with a high inflammatory response, increased complications of liver cirrhosis and occasionally high fatality rates.

Severity of acute gastrointestinal injury grade is a predictor of all-cause mortality in critically ill patients: a multicenter, prospective, observational study

Background

In 2012, the European Society of Intensive Care Medicine proposed a definition for acute gastrointestinal injury (AGI) based on current medical evidence and expert opinion. The aim of the present study was to evaluate the feasibility of using the current AGI grading system and to investigate the association between AGI severity grades with clinical outcome in critically ill patients.

Methods

Adult patients at 14 general intensive care units (ICUs) with an expected ICU stay ≥24 h were prospectively studied. The AGI grade was assessed daily on the basis of gastrointestinal (GI) symptoms, intra-abdominal pressures, and feeding intolerance (FI) in the first week of admission to the ICU.

Results

Among the 550 patients enrolled, 456 patients (82.9%) received mechanical ventilation, and 470 patients were identified for AGI. The distribution of the global AGI grade was 24.5% with grade I, 49.4% with grade II, 20.6% with grade III, and 5.5% with grade IV. AGI grading was positively correlated with 28- and 60-day mortality (P < 0.0001). Univariate Cox regression analysis showed that age, sepsis, diabetes mellitus, coronary artery disease, the use of vasoactive drugs, serum creatinine and lactate levels, mechanical ventilation, Acute Physiology and Chronic Health Evaluation II (APACHE II) score, and the global AGI grade were significantly (P ≤ 0.02) associated with 60-day mortality. In a multivariate analysis including these variables, diabetes mellitus (HR 1.43, 95% CI 1.03–1.87; P = 0.05), the use of vasoactive drugs (HR 1.56, 95% CI 1.12–2.11; P = 0.01), serum lactate (HR 1.15, 95% CI 1.06–1.24; P = 0.03), global AGI grade (HR 1.65, 95% CI 1.28–2.12; P = 0.008), and APACHE II score (HR 1.04, 95% CI 1.02–1.06; P < 0.001) were independently associated with 60-day mortality. In a subgroup analysis of 402 patients with 7-day survival, in addition to clinical predictors and the AGI grade on the first day of ICU stay, FI within the first week of ICU stay had an independent and incremental prognostic value for 60-day mortality (χ² = 41.9 vs. 52.2, P = 0.007).

Conclusions

The AGI grading scheme is useful for identifying the severity of GI dysfunction and could be used as a predictor of impaired outcomes. In addition, these results support the hypothesis that persistent FI within the first week of ICU stay is an independent determinant for mortality.

Trial registration

Chinese Clinical Trial Registry identifier: ChiCTR-OCS-13003824. Registered on 29 September 2013.

Electronic supplementary material

The online version of this article (doi:10.1186/s13054-017-1780-4) contains supplementary material, which is available to authorized users.

Microbiota-induced peritrophic matrix regulates midgut homeostasis and prevents systemic infection of malaria vector mosquitoes

Manipulation of the mosquito gut microbiota can lay the foundations for novel methods for disease transmission control. Mosquito blood feeding triggers a significant, transient increase of the gut microbiota, but little is known about the mechanisms by which the mosquito controls this bacterial growth whilst limiting inflammation of the gut epithelium. Here, we investigate the gut epithelial response to the changing microbiota load upon blood feeding in the malaria vector Anopheles coluzzii. We show that the synthesis and integrity of the peritrophic matrix, which physically separates the gut epithelium from its luminal contents, is microbiota dependent. We reveal that the peritrophic matrix limits the growth and persistence of Enterobacteriaceae within the gut, whilst preventing seeding of a systemic infection. Our results demonstrate that the peritrophic matrix is a key regulator of mosquito gut homeostasis and establish functional analogies between this and the mucus layers of the mammalian gastrointestinal tract.

When a female mosquito takes a blood meal from a human, the bacteria residing within its gut grow significantly. Following a blood meal, female mosquitoes produce a barrier within their gut, known as the peritrophic matrix, which physically separates the blood meal from the cells of the epithelium. Here, we show that the presence of bacteria in the gut is required for the synthesis of the peritrophic matrix. By experimentally disrupting this barrier, we find that this structure plays a role in limiting the extent to which bacteria of one particular family are able to grow and persist in the mosquito gut. We also find that the peritrophic matrix ensures that bacteria remain within the gut, preventing them from invading the mosquito body cavity. These results will be useful in designing disease control strategies that depend on the ability of bacteria to colonize and persist in relevant tissues in the mosquito host.

Microbiota, NASH, HCC and the potential role of probiotics

Hepatocellular carcinoma (HCC) accounts for the majority of primary liver cancers. Clearly identifiable risk factors are lacking in up to 30% of HCC patients and most of these cases are attributed to non-alcoholic fatty liver disease (NAFLD) and non-alcoholic steatohepatitis (NASH). Beyond the known risk factors for NAFLD, the intestinal microbiota, in particular dysbiosis (defined as any change in the composition of the microbiota commonly found in healthy conditions) is emerging as a new factor promoting the development of chronic liver diseases and HCC. Intestinal microbes produce a large array of bioactive molecules from mainly dietary compounds, establishing an intense microbiota-host transgenomic metabolism with a major impact on physiological and pathological conditions. A better knowledge of these 'new' pathways could help unravel the pathogenesis of HCC in NAFLD to devise new prevention strategies. Currently unsettled issues include the relative role of a 'negative microbiota' (in addition to the other known risk factors for NASH) and the putative prevention of NAFLD through modulation of the gut microbiota.

Effect of ceramide-1-phosphate transfer protein on intestinal bacterial translocation in severe acute pancreatitis

BACKGROUND AND OBJECTIVE

The aim of the study was to investigate the effects of ceramide-1-phosphate transfer protein (CPTP) on the intestinal epithelial tight junction proteins in patients with severe acute pancreatitis (SAP).

METHODS

Fifty patients with SAP were classified into two groups according to the presence of bacterial translocation (BT) in the blood. Thirty healthy individuals were included in the control group. The presence of BT was analyzed by polymerase chain reaction. The expression of tight junction proteins and CPTP was determined using immunohistochemistry and western blotting.

RESULTS

Bacterial DNA was detected in the peripheral blood of 62.0% of the patients with SAP. The expression of CPTP and tight junction proteins in SAP patients was lower than that in healthy controls. Among the patients with SAP, those positive for BT(+) showed a lower level of CPTP and occluding (OC) and zonula occludens-1 (ZO-1) expression and a higher level of IVA cPLA2 expression than BT(-) patients. Moreover, the expression of CPTP was significantly associated with ZO-1 and showed a negative correlation with expression of IVA cPLA2 in SAP-BT(+) patients.

CONCLUSIONS

CPTP affects the expression of tight junction proteins and may protects the intestinal epithelial barrier by downregulating the expression of IVA cPLA2.

CLABSI Risk Factors in the NICU: Potential for Prevention: A PICNIC Study

OBJECTIVE Central-line-associated bloodstream infections (CLABSI) are an important cause of morbidity and mortality in neonates. We aimed to determine whether intra-abdominal pathologies are an independent risk factor for CLABSI. METHODS We performed a retrospective matched case-control study of infants admitted to the neonatal intensive care units (NICUs) of the Montreal Children's Hospital (Montreal) and the Royal Alexandra Hospital, Edmonton, Canada. CLABSI cases that occurred between April 2009 and March 2014 were identified through local infection control databases. For each case, up to 3 controls were matched (National Healthcare Safety Network [NHSN] birth weight category, chronological age, and central venous catheter (CVC) dwell time at the time of CLABSI onset). Data were analyzed using conditional logistic regression. RESULTS We identified 120 cases and 293 controls. According to a matched univariate analysis, the following variables were significant risk factors for CLABSI: active intra-abdominal pathology (odds ratio [OR], 3.4; 95% confidence interval [CI], 1.8-6.4), abdominal surgery in the prior 7 days (OR, 3.5; 95% CI, 1.0-10.9); male sex (OR, 1.7; 95% CI, 1.1-2.6) and ≥3 heel punctures (OR, 4.0; 95% CI, 1.9-8.3). According to a multivariate matched analysis, intra-abdominal pathology (OR, 5.9; 95% CI, 2.5-14.1), and ≥3 heel punctures (OR, 5.4; 95% CI, 2.4-12.2) remained independent risk factors for CLABSI. CONCLUSION The presence of an active intra-abdominal pathology increased the risk of CLABSI by almost 6-fold. Similar to CLABSI in oncology patients, a subgroup of CLABSI with mucosal barrier injury should be considered for infants in the NICU with active intra-abdominal pathology. Infect Control Hosp Epidemiol 2016;1446-1452.

Post-splenectomy infections in chronic schistosomiasis as a consequence of bacterial translocation

INTRODUCTION

Bacterial translocation is the invasion of indigenous intestinal bacteria through the gut mucosa to normally sterile tissues and internal organs. Schistosomiasis may cause alterations in the immune system and damage to the intestines, portal system and mesenteric lymph nodes. This study investigated bacterial translocation and alterations in the intestinal microbiota and mucosa in schistosomiasis and splenectomized mice.

METHODS

Forty female 35-day-old Swiss Webster mice were divided into the following four groups with 10 animals each: schistosomotic (ESF), splenectomized schistosomotic (ESEF), splenectomized (EF) and control (CF). Infection was achieved by introduction of 50 Schistosoma mansoni (SLM) cercariae through the skin. At 125 days after birth, half of the parasitized and unparasitized mice were subjected to splenectomy. Body weights were recorded for one week after splenectomy; then, the mice were euthanized to study bacterial translocation, microbiota composition and intestinal morphometry.

RESULTS

We observed significant reductions in the weight increases in the EF, ESF and ESEF groups. There were increases of at least 1,000 CFU of intestinal microbiota bacteria in these groups compared with the CF. The EF, ESF and ESEF mice showed decreases in the heights and areas of villi and the total villus areas (perimeter). We observed frequent co-infections with various bacterial genera.

CONCLUSIONS

The ESEF mice showed a higher degree of sepsis. This finding may be associated with a reduction in the immune response associated with the absence of the spleen and a reduction in nutritional absorption strengthened by both of these factors (Schistosoma infection and splenectomy).

Microbiome and bacterial translocation in cirrhosis

Qualitative and quantitative changes in gut microbiota play a very important role in cirrhosis. Humans harbour around 100 quintillion gut bacteria, thus representing around 10 times more microbial cells than eukaryotic ones. The gastrointestinal tract is the largest surface area in the body and it is subject to constant exposure to these living microorganisms. The existing symbiosis, proven by the lack of proinflammatory response against commensal bacteria, implies the presence of clearly defined communication lines that contribute to the maintenance of homeostasis of the host. Therefore, alterations of gut flora seem to play a role in the pathogenesis and progress of multiple liver and gastrointestinal diseases. This has made its selective modification into an area of high therapeutic interest. Bacterial translocation is defined as the migration of bacteria or bacterial products from the intestines to the mesenteric lymph nodes. It follows that alteration in gut microbiota have shown importance, at least to some extent, in the pathogenesis of several complications arising from terminal liver disease, such as hepatic encephalopathy, portal hypertension and spontaneous bacterial peritonitis. This review sums up, firstly, how liver disease can alter the common composition of gut microbiota, and secondly, how this alteration contributes to the development of complications in cirrhosis.

Heat stroke

Heat stroke is a life-threatening condition clinically diagnosed as a severe elevation in body temperature with central nervous system dysfunction that often includes combativeness, delirium, seizures, and coma. Classic heat stroke primarily occurs in immunocompromised individuals during annual heat waves. Exertional heat stroke is observed in young fit individuals performing strenuous physical activity in hot or temperature environments. Long-term consequences of heat stroke are thought to be due to a systemic inflammatory response syndrome. This article provides a comprehensive review of recent advances in the identification of risk factors that predispose to heat stroke, the role of endotoxin and cytokines in mediation of multi-organ damage, the incidence of hypothermia and fever during heat stroke recovery, clinical biomarkers of organ damage severity, and protective cooling strategies. Risk factors include environmental factors, medications, drug use, compromised health status, and genetic conditions. The role of endotoxin and cytokines is discussed in the framework of research conducted over 30 years ago that requires reassessment to more clearly identify the role of these factors in the systemic inflammatory response syndrome. We challenge the notion that hypothalamic damage is responsible for thermoregulatory disturbances during heat stroke recovery and highlight recent advances in our understanding of the regulated nature of these responses. The need for more sensitive clinical biomarkers of organ damage is examined. Conventional and emerging cooling methods are discussed with reference to protection against peripheral organ damage and selective brain cooling.

Bacterial Translocation and Sample Contamination in Postmortem Microbiological Analyses

The diagnostic value of postmortem bacteriology has been discussed controversially for decades. In the study herein, contamination during sampling procedures and postmortem translocation were investigated to interpret postmortem microbiology results. One hundred medicolegal autopsy cases in total were included. Radiology, histology, bacteriology, and biochemistry were performed in all cases. Based on all investigation findings, 4 groups of cases were identified: death unrelated to infection, true infections, false positive (contamination during sampling procedures, postmortem translocation and mixed situations), and undetermined. The results of this study indicate that postmortem bacteriology provides useful data supporting infection-related deaths, especially when potentially significant observations are accompanied by consistent autopsy, histology, and biochemistry. Result interpretation requires careful evaluation of number and type of isolated microorganisms.