Increased intestinal permeability associated with infection in burn patients

Berberine decreases S100B generation to regulate gut vascular barrier permeability in mice with burn injury

Context: Berberine (BBR) can regulate enteric glial cells (EGCs) and the gut vascular barrier (GVB).Objective: To explore whether BBR regulates GVB permeability via the S100B pathway.Materials and methods: GVB hyperpermeability in C57BL/6J mice was induced by burns or S100B enema. BBR (25 or 50 mg/kg/d, 3 d) was gavaged preburn. S100B monoclonal antibody (S100BmAb) was i.v. injected postburn. Mouse intestinal microvascular endothelial cells (MIMECs) were treated with S100B, S100B plus BBR, or Z-IETD-FMK. GVB permeability was assayed by FITC-dextran, S100B by ELISA, caspase-8, β-catenin, occludin and PV-1 by immunoblot.Results: Burns elevated S100B in serum and in colonic mucosa to a peak (147.00 ± 4.95 ng/mL and 160.30 ± 8.50 ng/mg, respectively) at 36 h postburn, but BBR decreased burns-induced S100B in serum (126.20 ± 6.30 or 90.60 ± 3.78 ng/mL) and in mucosa (125.80 ± 12.40 or 91.20 ± 8.54 ng/mg). Burns raised GVB permeability (serum FITC-dextran 111.40 ± 8.56 pg/mL) at 48 h postburn, but BBR reduced GVB permeability (serum FITC-dextran 89.20 ± 6.98 or 68.60 ± 5.50 ng/mL). S100B enema (1 μM) aggravated burns-raised GVB permeability (142.80 ± 8.07 pg/mL) and PV-1, but the effect of S100B was antagonized by BBR. Z-IETD-FMK (5 μM) increased S100B-induced permeability to FITC-dextran (205.80 ± 9.70 to 263.80 ± 11.04 AUs) while reducing β-catenin in MIMECs. BBR (5 μM) reduced S100B-induced permeability (104.20 ± 9.65 AUs) and increased caspase-8, β-catenin and occludin.Discussion and conclusion: BBR decreases burns-induced GVB hyperpermeability via modulating S100B/caspase-8/β-catenin pathway and may involve EGCs.

Recent alcohol intake impacts microbiota in adult burn patients

Alcohol use is associated with an increased incidence of negative health outcomes in burn patients due to biological mechanisms that include a dysregulated inflammatory response and increased intestinal permeability. This study used phosphatidylethanol (PEth) in blood, a direct biomarker of recent alcohol use, to investigate associations between a recent history of alcohol use and the fecal microbiota, short chain fatty acids, and inflammatory markers in the first week after a burn injury for nineteen participants. Burn patients were grouped according to PEth levels of low or high and differences in the overall fecal microbial community were observed between these cohorts. Two genera that contributed to the differences and had higher relative abundance in the low PEth burn patient group were Akkermansia, a mucin degrading bacteria that improves intestinal barrier function, and Bacteroides, a potentially anti-inflammatory bacteria. There was no statistically significant difference between levels of short chain fatty acids or intestinal permeability across the two groups. To our knowledge, this study represents the first report to evaluate the effects of burn injury and recent alcohol use on early post burn microbiota dysbiosis, inflammatory response, and levels of short chain fatty acids. Future studies in this field are warranted to better understand the factors associated with negative health outcomes and develop interventional trials.

Early enteral nutrition and mobilization following head and neck surgery with free flap reconstruction

BACKGROUND

Perioperative management methods that reduce surgery-associated invasiveness and improve the quality of postoperative recovery are being promoted as enhanced recovery after surgery programs in various areas. Early enteral nutrition and mobilization are essential elements for enhanced recovery after surgery; however, their safety and feasibility are unclear in head and neck surgery with free tissue transfer reconstruction. This study aimed to clarify these uncertainties.

METHODS

This is a retrospective before-after study. From 2018 to 2022, 187 and 173 patients received conventional management on or before April 2020 and early management on or after May 2020, respectively. The conventional management and early management groups received enteral nutrition and mobilization on postoperative days 2 and 1, respectively. The primary outcome for safety assessment was the incidence of complications. The secondary outcome was the compliance rate of conventional management or early management for feasibility assessment and the length of hospital stay.

RESULTS

The clinical tumour-node-metastasis stage and American Society of Anesthesiologists physical status showed significant differences between the groups. In multivariable analysis, the early management group demonstrated a significantly lower incidence of treatment-required complication classified Clavien-Dindo Grade 2 and above (odds ratio = 0.57; 95% confidence interval = 0.31-0.92) and lower wound infection (odds ratio = 0.53; 95% confidence interval = 0.31-0.92). The early management group had lower compliance rate than the conventional management group; however, no statistically significant difference was observed (79.8% vs. 85.0%, P = 0.21).

CONCLUSION

Early management is safe and feasible following head and neck surgery with free tissue transfer reconstruction. It could reduce the complication rate and is considered a useful postoperative management method.

Ghrelin prevents lethality in a rat endotoxemic model through central effects on the vagal pathway and adenosine A2B signaling : Brain ghrelin and anti-septic action

Accumulating evidence suggest that ghrelin plays a role as an antiseptic peptide. The present study aimed to clarify whether the brain may be implicated ghrelin's antiseptic action. We examined the effect of brain ghrelin on survival in a novel endotoxemic model achieved by treating rats with lipopolysaccharide (LPS) and colchicine. The observation of survival stopped three days after chemicals' injection or at death. Intracisternal ghrelin dose-dependently reduced lethality in the endotoxemic model; meanwhile, neither intraperitoneal injection of ghrelin nor intracisternal des-acyl-ghrelin injection affected the mortality rate. The brain ghrelin-induced lethality reduction was significantly blocked by surgical vagotomy. Moreover, intracisternal injection of a ghrelin receptor antagonist blocked the improved survival achieved by intracisternal ghrelin injection or intravenous 2-deoxy-d-glucose administration. Intracisternal injection of an adenosine A2B receptor agonist reduced the lethality and the ghrelin-induced improvement of survival was blocked by adenosine A2B receptor antagonist. I addition, intracisternal ghrelin significantly blocked the colonic hyperpermeability produced by LPS and colchicine. These results suggest that ghrelin acts centrally to reduce endotoxemic lethality. Accordingly, activation of the vagal pathway and adenosine A2B receptors in the brain may be implicated in the ghrelin-induced increased survival. Since the efferent vagus nerve mediates anti-inflammatory mechanisms, we speculate that the vagal cholinergic anti-inflammatory pathway is implicated in the decreased septic lethality caused by brain ghrelin.

Interconnections of Pseudomonas aeruginosa Quorum-Sensing Systems in Intestinal Permeability and Inflammation

Quorum sensing (QS) is a highly conserved microbial communication mechanism based on the production and sensing of secreted signaling molecules. The recalcitrant pathogen Pseudomonas aeruginosa is a problematic nosocomial pathogen with complex interconnected QS systems controlling multiple virulence functions. The relevance of QS in P. aeruginosa pathogenesis is well established; however, the regulatory interrelationships of the three major QS systems, LasR/LasI, MvfR (PqsR)/PqsABCD, and RhlR/RhlI, have been studied primarily in vitro. It is, therefore, unclear how these relationships translate to the host environment during infection. Here, we use a collection of P. aeruginosa QS mutants of the three major QS systems to assess the interconnections and contributions in intestinal inflammation and barrier function in vivo. This work reveals that MvfR, not LasR or RhlR, promotes intestinal inflammation during infection. In contrast, we find that P. aeruginosa-driven murine intestinal permeability is controlled by an interconnected QS network involving all three regulators, with MvfR situated upstream of LasR and RhlR. This study demonstrates the importance of understanding the interrelationships of the QS systems during infection and provides critical insights for developing successful antivirulence strategies. Moreover, this work provides a framework to interrogate QS systems in physiologically relevant settings. IMPORTANCE Pseudomonas aeruginosa is a common multidrug-resistant bacterial pathogen that seriously threatens critically ill and immunocompromised patients. Intestinal colonization by this pathogen is associated with elevated mortality rates. Disrupting bacterial communication is a desirable anti-infective approach since these systems coordinate multiple acute and chronic virulence functions in P. aeruginosa. Here, we investigate the role of each of the three major communication systems in the host intestinal functions. This work reveals that P. aeruginosa influences intestinal inflammation and permeability through distinct mechanisms.

Anti-Inflammatory Properties of Plasma from Children with Short Bowel Syndrome

Sepsis, resulting from a dysregulated host immune response to invading pathogens, is the leading cause of mortality in critically ill patients worldwide. Immunomodulatory treatment for sepsis is currently lacking. Children with short bowel syndrome (SBS) may present with less severe symptoms during gram-negative bacteremia. We, therefore, tested the hypothesis that plasma from children with SBS could confer protection against Escherichia coli sepsis. We showed that SBS plasma at 5% and 10% concentrations significantly (p < 0.05) inhibited the production of both TNF-α and IL-6 induced by either E. coli- or LPS-stimulated host cells when compared to plasma from healthy controls. Furthermore, mice treated intravenously with select plasma samples from SBS or healthy subjects had reduced proinflammatory cytokine levels in plasma and a significant survival advantage after E. coli infection. However, SBS plasma was not more protective than the plasma of healthy subjects, suggesting that children with SBS have other immunomodulatory mechanisms, in addition to neutralizing antibodies, to alleviate their symptoms during gram-negative sepsis.

Centrally administered butyrate improves gut barrier function, visceral sensation and septic lethality in rats

Short chain fatty acids readily crosses the gut-blood and blood-brain barrier and acts centrally to influence neuronal signaling. We hypothesized that butyrate, a short-chain fatty acid produced by bacterial fermentation, in the central nervous system may play a role in the regulation of intestinal functions. Colonic permeability and visceral sensation was evaluated in rats. Septic lethality was evaluated in a sepsis model induced by subcutaneous administration of both lipopolysaccharide and colchicine. Intracisternal butyrate dose-dependently improved colonic hyperpermeability and visceral nociception. In contrast, subcutaneous injection of butyrate failed to change it. Intracisternal orexin 1 receptor antagonist or surgical vagotomy blocked the central butyrate-induced improvement of colonic hyperpermeability. The improvement of intestinal hyperpermeability by central butyrate or intracisternal orexin-A was blocked by cannabinoid 1 or 2 receptor antagonist. Intracisternal butyrate significantly improved survival period in septic rats. These results suggest that butyrate acts in the central nervous system to improve gut permeability and visceral nociception through cannabinoid signaling. Endogenous orexin in the brain may mediate the reduction of intestinal hyperpermeability by central butyrate through the vagus nerve. We would suggest that improvement of leaky gut by central butyrate may induce visceral antinociception and protection from septic lethality.

Association between early enteral nutrition and clinical outcome in patients with severe acute heart failure who require invasive mechanical ventilation

BACKGROUND

This study aimed to examine the association between early enteral nutrition (EEN) and clinical outcome in patients with severe acute heart failure (AHF).

METHODS

This retrospective observational study enrolled consecutive patients with AHF who required continuous invasive mechanical ventilation (IMV) for >48 h and were admitted to a single-center cardiac care unit (CCU). The primary outcome was CCU length of stay (LoS). We compared patients who were initiated on EN within 48 h of intubation (EEN group) with those who were initiated on EN after 49 h of intubation (delayed EN [DEN] group). Multivariate logistic regression analysis was performed to determine independent factors for primary and secondary outcomes. CCU LoS and IMV time were categorized using the median.

RESULTS

We included 86 patients with AHF (EEN group, n = 56; DEN group, n = 30) who met the inclusion criteria. The median CCU LoS was significantly shorter in the EEN group (10 [8-15] days) than in the DEN group (15 [12-26] days, P = .007). Multivariate analysis indicated that time to EN initiation was an independent factor for CCU LoS (odds ratio [OR], 8.39; 95% confidence interval [CI], 2.18-32.20; P = .002), IMV time (OR, 4.84; 95% CI, 1.37-17.20; P = .015), and incidence of infection (OR, 2.73; 95％ CI, 1.04-7.18; P = .042).

CONCLUSION

EEN (within 48 h of intubation) for patients with severe AHF who require continuous IMV might be associated with reduced CCU LoS, IMV time, and incidence of infection.

Targeting the Hindgut to Improve Health and Performance in Cattle

An adequate gastrointestinal barrier function is essential to preserve animal health and well-being. Suboptimal gut health results in the translocation of contents from the gastrointestinal lumen across the epithelium, inducing local and systemic inflammatory responses. Inflammation is characterized by high energetic and nutrient requirements, which diverts resources away from production. Further, barrier function defects and inflammation have been both associated with several metabolic diseases in dairy cattle and liver abscesses in feedlots. The gastrointestinal tract is sensitive to several factors intrinsic to the productive cycles of dairy and beef cattle. Among them, high grain diets, commonly fed to support lactation and growth, are potentially detrimental for rumen health due to their increased fermentability, representing the main risk factor for the development of acidosis. Furthermore, the increase in dietary starch associated with such rations frequently results in an increase in the bypass fraction reaching distal sections of the intestine. The effects of high grain diets in the hindgut are comparable to those in the rumen and, thus, hindgut acidosis likely plays a role in grain overload syndrome. However, the relative contribution of the hindgut to this syndrome remains unknown. Nutritional strategies designed to support hindgut health might represent an opportunity to sustain health and performance in bovines.

Targeting the gut to prevent sepsis from a cutaneous burn

Severe burn injury induces gut barrier dysfunction and subsequently a profound systemic inflammatory response. In the present study, we examined the role of the small intestinal brush border enzyme, intestinal alkaline phosphatase (IAP), in preserving gut barrier function and preventing systemic inflammation after burn wound infection in mice. Mice were subjected to a 30% total body surface area dorsal burn with or without intradermal injection of Pseudomonas aeruginosa. Mice were gavaged with 2000 units of IAP or vehicle at 3 and 12 hours after the insult. We found that both endogenously produced and exogenously supplemented IAP significantly reduced gut barrier damage, decreased bacterial translocation to the systemic organs, attenuated systemic inflammation, and improved survival in this burn wound infection model. IAP attenuated liver inflammation and reduced the proinflammatory characteristics of portal serum. Furthermore, we found that intestinal luminal contents of burn wound-infected mice negatively impacted the intestinal epithelial integrity compared with luminal contents of control mice and that IAP supplementation preserved monolayer integrity. These results indicate that oral IAP therapy may represent an approach to preserving gut barrier function, blocking proinflammatory triggers from entering the portal system, preventing gut-induced systemic inflammation, and improving survival after severe burn injuries.

Understanding acute burn injury as a chronic disease

While treatment for burn injury has improved significantly over the past few decades, reducing mortality and improving patient outcomes, recent evidence has revealed that burn injury is associated with a number of secondary pathologies, many of which arise long after the initial injury has healed. Population studies have linked burn injury with increased risk of cancer, cardiovascular disease, nervous system disorders, diabetes, musculoskeletal disorders, gastrointestinal disease, infections, anxiety and depression. The wide range of secondary pathologies indicates that burn can cause sustained disruption of homeostasis, presenting new challenges for post-burn care. Understanding burn injury as a chronic disease will improve patient care, providing evidence for better long-term support and monitoring of patients. Through focused research into the mechanisms underpinning long-term dysfunction, a better understanding of burn injury pathology may help with the development of preventative treatments to improve long-term health outcomes. The review will outline evidence of long-term health effects, possible mechanisms linking burn injury to long-term health and current research into burns as a chronic disease.

Energy Expenditure and Protein Requirements Following Burn Injury

Severe burn injuries have long been known to have a profound effect on metabolic equilibrium that can persist after resolution of the cutaneous injuries. Following burn injury, metabolism is a dynamic state resulting in the need for frequent interval reassessment over the course of the care continuum. The acute phase of injury transitions to chronic alterations in macronutrient utilization characterized by futile energy cycling and disproportionate catabolism of skeletal muscle. Protein supplementation appears to be preferentially distributed to the burn wound rather than the skeletal muscle pool. Accurate assessment of caloric and protein requirements is extremely difficult in these patients but is an essential step in efforts to attenuate functional impairment. Indirect calorimetry should be utilized to determine caloric requirements, but trophic feeding strategies are preferred in the initial resuscitative phase to prevent overfeeding while maintaining enteric and immune function. Controversy persists regarding optimal protein targets, and weight-based estimates remain the norm. Exogenous protein and caloric provision performed in isolation is insufficient to optimize outcomes and should be incorporated within a multidisciplinary approach to include muscle loading and pharmaceutical adjuncts.

Intestinal barrier dysfunction in severe burn injury

Severe burn injury is often accompanied by intestinal barrier dysfunction, which is closely associated with post-burn shock, bacterial translocation, systemic inflammatory response syndrome, hypercatabolism, sepsis, multiple organ dysfunction syndrome, and other complications. The intestinal epithelium forms a physical barrier that separates the intestinal lumen from the internal milieu, in which the tight junction plays a principal role. It has been well documented that after severe burn injury, many factors such as stress, ischemia/hypoxia, proinflammatory cytokines, and endotoxins can induce intestinal barrier dysfunction via multiple signaling pathways. Recent advances have provided new insights into the mechanisms and the therapeutic strategies of intestinal epithelial barrier dysfunction associated with severe burn injury. In this review, we will describe the current knowledge of the mechanisms involved in intestinal barrier dysfunction in response to severe burn injury and the emerging therapies for treating intestinal barrier dysfunction following severe burn injury.

Targeting bacterial quorum sensing shows promise in improving intestinal barrier function following burn‑site infection

Burn-site infections, commonly due to Pseudomonas aeruginosa, have been associated with deranged intestinal integrity, allowing bacteria and their products to translocate from the gut to the circulatory system. The P. aeruginosa quorum sensing (QS) transcription factor MvfR (PqsR) controls the expression of numerous virulence factors, and the synthesis of several toxic products. However, the role of QS in intestinal integrity alterations, to the best of our knowledge, has not been previously investigated. Using a proven anti-MvfR, anti-virulence agent, the in vivo results of the present study revealed that inhibition of MvfR function significantly decreased Fluorescein Isothiocyanate-Dextran (FITC-Dextran) flow from the intestine to the systemic circulation, diminished bacterial translocation from the intestine to mesenteric lymph nodes (MLNs), and improved tight junction integrity in thermally injured and infected mice. In addition, the MvfR antagonist administration alleviates the intestinal inflammation, as demonstrated by reduced ileal TNF-α and fecal lipocalin-2 concentrations. In addition, it is associated with lower levels of circulating endotoxin and decreased P. aeruginosa dissemination from the burn wound to the ileum. Collectively, these results hold great promise that the inhibition of this QS system mitigates gut hyperpermeability by attenuating the derangement of morphological and immune aspects of the intestinal barrier, suggesting that MvfR function is crucial in the deterioration of intestinal integrity following P. aeruginosa burn-site infection. Therefore, an anti-virulence approach targeting MvfR, could potentially offer a novel therapeutic approach against multi-drug resistant P. aeruginosa infections following thermal injuries. Since this approach is targeting virulence pathways that are non-essential for growth or viability, our strategy is hypothesized to minimize the development of bacterial resistance, and preserve the beneficial enteric microbes, while improving intestinal integrity that is deranged as a result of burn and infection.

Investigating Gut Permeability in Animal Models of Disease

A growing number of investigations report the association between gut permeability and intestinal or extra-intestinal disorders under the basis that translocation of gut luminal contents could affect tissue function, either directly or indirectly. Still, in many cases it is unknown whether disruption of the gut barrier is a causative agent or a consequence of these conditions. Adequate experimental models are therefore required to further understand the pathophysiology of health disorders associated to gut barrier disruption and to develop and test pharmacological treatments. Here, we review the current animal models that display enhanced intestinal permeability, and discuss (1) their suitability to address mechanistic questions, such as the association between gut barrier alterations and disease and (2) their validity to test potential treatments for pathologies that are characterized by enhanced intestinal permeability.

Quantitative Measure of Intestinal Permeability Using Blue Food Coloring

BACKGROUND

Loss of intestinal barrier integrity plays a fundamental role in the pathogenesis of various gastrointestinal diseases and is implicated in the onset of sepsis and multiple organ failure. An array of methods to assess different aspects of intestinal barrier function suffers from lack of sensitivity, prolonged periods of specimen collection, or high expense. We have developed a technique to measure the concentration of the food dye FD&C Blue #1 from blood and sought to assess its utility in measuring intestinal barrier function in humans.

MATERIALS AND METHODS

Four healthy volunteers and 10 critically ill subjects in the intensive care unit were recruited in accordance with an institutional review board approved protocol. Subjects were given 0.5 mg/kg Blue #1 enterally as an aqueous solution of diluted food coloring. Five blood specimens were drawn per subject: 0 h (before dose), 1, 2, 4, and 8 h. After plasma isolation, organic extracts were analyzed by high-performance liquid chromatography/mass spectrometry detecting the presence of unmodified dye.

RESULTS

We found no baseline detectable absorption in healthy volunteers. After including the subjects in the intensive care unit, we compared dye absorption in the six subjects who met criteria for septic shock with the eight who did not. Septic patients demonstrated significantly greater absorption of Blue #1 after 2 h.

CONCLUSIONS

We have developed a novel, easy-to-use method to measure intestinal barrier integrity using a food grade dye detectable by mass spectrometry analysis of patient blood following oral administration.

Preoperative Gastroesophageal Reflux Disorder Is Associated With Increased Morbidity in Patients Undergoing Abdominal Surgery

BACKGROUND

In North America, the prevalence of gastroesophageal reflux disorder ranges from 18.1% to 27.8%. We measured the risk posed by preoperative esophageal disease for patients undergoing abdominal operations.

METHOD

American College of Surgeons National Surgical Quality Improvement Program (ACS NSQIP; 2005-2015) data were merged with institutional clinical data repository records to identify esophageal disease in surgical patients undergoing intra-abdominal procedures. Patients with esophageal disease were classified as gastroesophageal reflux disorder (GERD) or other, which included patients with esophageal stricture, spasm, ulcer, or diverticuli, achalasia, esophagitis, reflux esophagitis, Barrett's esophagus, and multiple esophageal diagnoses, excluding GERD. ACS NSQIP-targeted procedure groups included were colectomy, proctectomy, ventral hernia repair, bariatric surgery, hepatectomy, appendectomy, abdominal aortic aneurysm repair, open aortoiliac repair, hysterectomy, myomectomy, and oophorectomy. Multivariable logistic regression was used to model postoperative complication rates, adjusting for ACS NSQIP risk of morbidity, demographic factors, ACS NSQIP-targeted procedure groups, and open versus laparoscopic surgery.

RESULTS

Of 9172 intra-abdominal cases, 21.3% had preoperative esophageal disease (19.6% GERD and 1.7% other). After adjustment, patients with GERD were at higher risk for experiencing a number of complications, including all-cause 30-d complication (odds ratio [OR] = 1.21, 95% confidence interval [CI] 1.05-1.41, P = 0.044), renal complication (OR = 1.43, 95% CI 1.09-1.87, P = 0.036), wound complication (OR = 1.40, 95% CI 1.10-1.79, P = 0.028), and readmission within 30 d (OR = 1.66, 95% CI 1.35-2.04, P < 0.001).

CONCLUSIONS

Preoperative GERD is associated with increased postoperative complication rate. Surgeons should consider assessing GERD in patients undergoing abdominal operations.

Severe Burn-Induced Intestinal Epithelial Barrier Dysfunction Is Associated With Endoplasmic Reticulum Stress and Autophagy in Mice

The disruption of intestinal barrier plays a vital role in the pathophysiological changes after severe burn injury, however, the underlying mechanisms are poorly understood. Severe burn causes the disruption of intestinal tight junction (TJ) barrier. Previous studies have shown that endoplasmic reticulum (ER) stress and autophagy are closely associated with the impairment of intestinal mucosa. Thus, we hypothesize that ER stress and autophagy are likely involved in burn injury-induced intestinal epithelial barrier dysfunction. Mice received a 30% total body surface area (TBSA) full-thickness burn, and were sacrificed at 0, 1, 2, 6, 12 and 24 h postburn. The results showed that intestinal permeability was increased significantly after burn injury, accompanied by the damage of mucosa and the alteration of TJ proteins. Severe burn induced ER stress, as indicated by increased intraluminal chaperone binding protein (BIP), CCAAT/enhancer-binding protein homologous protein (CHOP) and inositol-requiring enzyme 1(IRE1)/X-box binding protein 1 splicing (XBP1). Autophagy was activated after burn injury, as evidenced by the increase of autophagy related protein 5 (ATG5), Beclin 1 and LC3II/LC3I ratio and the decrease of p62. Besides, the number of autophagosomes was also increased after burn injury. The levels of p-PI3K(Ser191), p-PI3K(Ser262), p-AKT(Ser473), and p-mTOR were decreased postburn, suggesting that autophagy-related PI3K/AKT/mTOR pathway is involved in the intestinal epithelial barrier dysfunction following severe burn. In summary, severe burn injury induces the ER stress and autophagy in intestinal epithelia, leading to the disruption of intestinal barrier.

Experimental Assessment of Chemotherapy-induced Early Intestinal Damage in Colon Cancer the Lactulose-mannitol Permeability Test

Aims and Background

Although chemotherapy plays an important role in the management and cure of cancer, it has undesiderable side effects mostly affecting the bone marrow and gastrointestinal tract, which greatly limit patient compliance and treatment efficacy.

Methods

The lactulose-mannitol test was used to assess intestinal mucosa damage 48 hours after the end of the first adjuvant chemotherapy cycle with 5-fluorouracil (5-FU) and levamisole in 12 patients with colon cancer. Fifteen age- and sex-matched subjects were studied as controls. The excreted amount of lactulose and mannitol was expressed as the percentage of the administered doses recovered in the urine as well as their ratio.

Results

The percent urinary recovery of lactulose was significantly (P <0.001) higher in colon cancer patients (1.1 ± 0.5%) than in the control group (0.3 ± 0.03%), whereas the mannitol recovery was only slightly reduced in the former. As a result, the lactulose/mannitol excretion ratio was significantly (P <0.001) higher in colon cancer patients (0.07 ± 0.03) than in the control group (0.01 ± 0.01).

Conclusions

As assessed by the lactulose-mannitol test, the combined chemotherapy regimen with 5-FU and levamisole affects mainly the barrier function of the intestinal mucosa rather than its absorption capacity. The toxic effect seems to be attributable to the 5-FU molecule rather than to levamisole. The lactulose-mannitol test is a simple, safe and reliable tool to evaluate chemotherapy-induced early damage to the intestinal epithelium, in particular when new kinds of substances are being administered. Its use in clinical practice seems appropriate to establish the correct timing of drug administration, thereby enhancing treatment efficacy and improving patient compliance.

Targeting palmitoyl acyltransferase ZDHHC21 improves gut epithelial barrier dysfunction resulting from burn-induced systemic inflammation

Clinical studies in burn patients demonstrate a close association between leaky guts and increased incidence or severity of sepsis and other complications. Severe thermal injury triggers intestinal inflammation that contributes to intestinal epithelial hyperpermeability, which exacerbates systemic response leading to multiple organ failure and sepsis. In this study, we identified a significant function of a particular palmitoyl acyltransferase, zinc finger DHHC domain-containing protein-21 (ZDHHC21), in mediating signaling events required for gut hyperpermeability induced by inflammation. Using quantitative PCR, we show that ZDHHC21 mRNA production was enhanced twofold when intestinal epithelial cells were treated with TNF-α-IFN-γ in vitro. In addition, pharmacological targeting of palmitoyl acyltransferases with 2-bromopalmitate (2-BP) showed significant improvement in TNF-α-IFN-γ-mediated epithelial barrier dysfunction by using electric cell-substrate impedance-sensing assays, as well as FITC-labeled dextran permeability assays. Using acyl-biotin exchange assay and click chemistry, we show that TNF-α-IFN-γ treatment of intestinal epithelial cells results in enhanced detection of total palmitoylated proteins and this response is inhibited by 2-BP. Using ZDHHC21-deficient mice or wild-type mice treated with 2-BP, we showed that mice with impaired ZDHHC21 expression or pharmacological inhibition resulted in attenuated intestinal barrier dysfunction caused by thermal injury. Moreover, hematoxylin and eosin staining of the small intestine, as well as transmission electron microscopy, showed that mice with genetic interruption of ZDHHC21 had attenuated villus structure disorganization associated with thermal injury-induced intestinal barrier damage. Taken together, these results suggest an important role of ZDHHC21 in mediating gut hyperpermeability resulting from thermal injury.NEW & NOTEWORTHY Increased mucosal permeability in the gut is one of the major complications following severe burn. Here we report the novel finding that zinc finger DHHC domain-containing protein-21 (ZDHHC21) mediates gut epithelial hyperpermeability resulting from an experimental model of thermal injury. The hyperpermeability response was significantly attenuated with a pharmacological inhibitor of palmitoyl acyltransferases and in mice with genetic ablation of ZDHHC21. These findings suggest that ZDHHC21 may serve as a novel therapeutic target for treating burn-induced intestinal barrier dysfunction.

Analysis of differentially expressed genes in white blood cells isolated from patients with major burn injuries

The aim of the present study was to identify differentially expressed genes (DEGs) and their related functions and pathways of major burn injuries, and to prevent the occurrence of complications. The expression profiling of E-GEOD-37069 was downloaded from ArrayExpress Archive. The DEGs of major burn injuries were identified. Gene Ontology (GO) and Kyoto Encyclopedia of Gene and Genomes (KEGG) functional enrichment analysis were then performed for the DEGs. Based on the KEGG database, a pathway relationship network was constructed, and DEGs in significant GO terms and pathways were investigated. Gene signal network and gene co-expression network of these inserted DEGs were constructed. A total of 3,328 DEGs of major burn injuries were identified, including 1,337 up- and 1,991 downregulated DEGs. These DEGs were mainly enriched into various GO terms, including transcription, DNA-dependent, signal transduction and blood coagulation. Moreover, they were also enriched into different pathways, such as hematopoietic cell lineage, metabolic pathway and chemokine signaling pathway. The pathway relationship network was constructed with 72 nodes. The MAPK signaling pathway was the hub node. Based on the same gene symbol, 702 DEGs were obtained, identified in both GO terms and pathways. Finally, the gene signaling network and gene co-expression network were constructed with 391 and 128 nodes, respectively. These identified DEGs, including GNB2, LILRA2, ARRB2 and ARHGEF2, may be potential key genes involved in the treatment of major burn injuries and prevention of complications.

Effects of Pediatric Burns on Gastrointestinal Diseases: A Population-Based Study

The systemic responses triggered by burns have been shown to include effects on the gastrointestinal tract. However, it is not clear if these changes lead to long-term gastrointestinal morbidity in patients with burns. The aim of this study was to assess if pediatric burns are associated with increased hospital use for gastrointestinal diseases after discharge for the initial injury. A population-based longitudinal study was performed using linked hospital and death data from Western Australia for children younger than 15 years when hospitalized for a first burn injury (n = 10,436) between 1980 and 2012, along with a frequency-matched noninjury comparison cohort, randomly selected from Western Australia's birth registrations (n = 40,819). Crude admission rates and cumulative length of stay for digestive diseases were calculated. Negative binomial and Cox proportional hazards regression modeling were used to generate incidence rate ratios (IRRs) and hazard ratios, respectively. After discharge, the pediatric burn cohort experienced twice the rate of gastrointestinal disease admissions (IRR, 95% confidence interval [CI]: 2.03, 1.56-2.65), spent over twice as long in hospital (IRR, 95% CI: 2.23, 1.67-2.98), and had a higher rate of first-time or incident gastrointestinal disease admissions (hazard ratio, 95% CI: 1.18, 1.08-1.29) when compared with the uninjured cohort, after adjusting for demographic and preexisting health factors. Children who experience a burn injury hospitalization are at increased risk of postburn hospital service use for gastrointestinal diseases when compared with uninjured children.

Burn leads to long-term elevated admissions to hospital for gastrointestinal disease in a West Australian population based study

BACKGROUND

While the most obvious impact of burn is on the skin, systemic responses also occur after burn, including intestinal inflammation. The objective of this study was to assess if burns are associated with increased long-term admissions for gastrointestinal diseases.

METHODS

A population-based longitudinal study using linked hospital morbidity and death data from Western Australia was undertaken of adults aged at least 15 years when hospitalized for a first burn (n=20,561) in 1980-2012. A frequency matched non-injury comparison cohort was randomly selected from Western Australia's birth registrations and electoral roll (n=80,960). Crude admission rates and summed days in hospital for digestive diseases were calculated. Negative binomial and Cox proportional hazards regression modeling were used to generate incidence rate ratios (IRR) and hazard ratios (HR), respectively.

RESULTS

After adjustment for demographic factors and pre-existing health status, the burn cohort had 1.54 times (95% confidence interval (CI): 1.47-1.62) as many admissions and almost three times the number of days in hospital with a digestive system diagnosis (IRR, 95% CI: 2.90, 2.60-3.25) than the uninjured cohort. Significantly elevated adjusted post-burn incident rates were identified, with the risk decreasing with increasing time: in the first month (HR, 95% CI: 3.02, 1.89-4.82), from one month to five years (HR, 95% CI: 1.42, 1.31-1.54), and from five to twenty years after burn (HR, 95% CI: 1.13, 1.06-1.20).

CONCLUSIONS

Findings of increased hospital admission rates and prolonged length of hospital stay for gastrointestinal diseases in the burn cohort provide evidence to support that burns have effects that persist long after the initial injury.

Differential effects of an infusion of endotoxin on proximal and distal feline jejunal permeability

The effects of an intravenous infusion of endotoxin (750 μg/kg) or an equal volume of saline solution (control) on the proximal and distal jejunal permeability and blood flow were evaluated in cats. In 8 cats, proximal and distal jejunal segments were isolated and mucosal clearance of 51Cr-ethylenediaminetetraacetic acid (EDTA) was measured. The mucosal clearance in the distal loop was not altered by endotoxin infusion in 6 cats given endotoxin or 2 cats given saline solution. In 6 cats given endotoxin, the proximal jejunal segment exhibited a 10-fold increase in mucosal permeability. In contrast, mucosal clearance remained stable in the proximal jejunal loop in 2 cats infused with saline solution.

In a second group of 13 cats (7 cats infused with endotoxin; 6 cats infused with saline solution), blood flow to the proximal and distal segments was measured. Either endotoxin (n = 7) or saline solution (n = 6) did not significantly alter blood flow to the proximal and distal jejunum in these experiments.

Samples of proximal and distal jejunum were collected from 12 cats (6 cats infused with endotoxin and 6 cats infused with saline solution). There was significantly more epithelial necrosis in the endotoxin treated cats than in the saline treated cats. Neutrophil infiltration was greater in the jejunal segments of endotoxin treated cats than in the jejunal segments of saline treated cats. In the endotoxin treated cats, there was significantly greater necrosis in the proximal jejunal segment than in the distal jejunal segment. There were no significant differences in numbers of neutrophils in the proximal and distal jejunal segments.

These results demonstrate that the proximal jejunum is more sensitive to endotoxin-induced increases in mucosal permeability than is the distal jejunum. The increases in mucosal permeability in the proximal jejunum were not accompanied by significant reductions in jejunal arterial blood flow. Endotoxemia induced neutrophil infiltration to the proximal and distal jejunum.

The recovery effects of Perinereis aibuhitensis Grube added to enteral immune-enhancing nutrition in severely burned mice

The recovery effects ofPerinereis aibuhitensisGrube added to early enteral nutrition (EEN) were investigated.

Translocation of gut flora and its role in sepsis

Bacterial translocation is the invasion of indigenous intestinal bacteria through the gut mucosa to normally sterile tissues and the internal organs. Sometimes instead of bacteria, inflammatory compounds are responsible for clinical symptoms as in systemic inflammatory response syndrome (SIRS). The difference between sepsis and SIRS is that pathogenic bacteria are isolated from patients with sepsis but not with those of SIRS. Bacterial translocation occurs more frequently in patients with intestinal obstruction and in immunocompromised patients and is the cause of subsequent sepsis. Factors that can trigger bacterial translocation from the gut are host immune deficiencies and immunosuppression, disturbances in normal ecological balance of gut, mucosal barrier permeability, obstructive jaundice, stress, etc. Bacterial translocation occurs through the transcellular and the paracellular pathways and can be measured both directly by culture of mesenteric lymph nodes and indirectly by using labeled bacteria, peripheral blood culture, detection of microbial DNA or endotoxin and urinary excretion of non-metabolisable sugars. Bacterial translocation may be a normal phenomenon occurring on frequent basis in healthy individuals without any deleterious consequences. But when the immune system is challenged extensively, it breaks down and results in septic complications at different sites away from the main focus. The factors released from the gut and carried in the mesenteric lymphatics but not in the portal blood are enough to cause multi-organ failure. Thus, bacterial translocation may be a promoter of sepsis but not the initiator. This paper reviews literature on the translocation of gut flora and its role in causing sepsis.

Effect of probiotic supplementation on bacterial translocation in common bile duct obstruction

OBJECTIVE

To investigate the effects of probiotics on bacterial translocation in the obstructive common bile duct with comparison to an enteral product containing arginine and glutamine.

MATERIAL AND METHOD

In our study, 40 Sprague-Dawley rats each weighing 250-300 g were used. Animals in Group 1 (sham) were laparatomized and fed standard chow supplemented with physiologic saline at daily doses of 2 ml through orogastric tube for 7 days. Common bile ducts of the animals in the other groups were ligated with 3/0 silk sutures. Group 2 (control group) was fed standard chow supplemented with daily doses of 2 ml physiologic saline. Group 3 (probiotic group) was fed standard chow supplemented with a probiotic solution (Acidophilus plus) containing strains of Lactobacillus acidophilus, Bifidobacterium bifidum and Lactobacillus bulgaricus at a daily doses of 2 × 10(9) colony forming units (CFU). Group 4 (formula group) was fed only an enteral solution (Stresson Multi Fiber) containing glutamine, arginine and a medium-chain fatty acid at daily doses of 2 g/kg. At the end of the 7th day, all animals were relaparatomized, and to determine bacterial translocation, aerobic, and anaerobic cultures were obtained from the specimens of mesenteric lymph nodes, intestinal mucosa, and blood samples. Smear cultures prepared from caecum were examined to determine the number of CFU. Finally, for histological examination specimens were excised from terminal ileum, and oxidative damage was assessed in liver tissues. Afterwards all animals were killed.

RESULTS

Moderately lesser degrees of bacterial translocation, and mucosal damage were seen in Groups 3, and 4 relative to Group 2 (p < 0.05). In Group 4, any difference was not seen in the number of cecal bacteria relative to baseline values, while in Group 3, significant decrease in cecal colonization was seen. Among all groups, a significant difference between levels of malondialdehyde, and glutathione was not observed.

CONCLUSION

At the end of our study, we have concluded that both probiotics, and enteral diets which contain immunomodulators such as glutamine, and arginine alleviate bacterial translocation, and impairment of intestinal mucosa.

Role of Motility in the Endogenous Pseudomonas aeruginosa Sepsis after burn

We investigated the relationship between bacterial motility and the lethal endogenous sepsis after burn in mice orally challenged with Pseudomonas aeruginosa, by using motility mutants. The mortality rates of postburn endogenous sepsis in mice orally challenged with low-motility mutants (strains B16-40 and B16-46) were 12% and 7.7%, respectively. By contrast, the mortality rates in mice who had been fed a high-motility mutant (B16-52) or the parental P. aeruginosa B16 (a high-motility strain) were 36% and 33%, respectively. Significant differences were found for mortality rates in groups fed the high-motility or lowmotility strains. A multiple regression analysis examining the effect of motility, number of cecal P. aeruginosa cells, and production of exotoxin A and total protease on the murine mortality rates associated with the 3 motility mutants and the parental strain showed a linear relationship between murine mortality and bacterial motility. In addition, when human monoclonal antibody specific for type-b flagella proteins of P. aeruginosa was intravenously administrated to mice orally challenged with P. aeruginosa B16, the mortality rate significantly decreased to 5.6%, compared with 33% in similar mice given intravenous saline. These results suggest that the occurrence of the lethal endogenous sepsis after burn in mice was closely related to the motility of the P. aeruginosa colonized in their intestinal tract, and that motility is an important virulence factor in endogenous P. aeruginosa sepsis after burn injury.

Drug absorption, distribution, metabolism and excretion considerations in critically ill adults

INTRODUCTION

All critically ill patients require medication to treat organ dysfunction. However, the pharmacokinetics of drugs used to treat these patients is complex due to frequent alterations in drug absorption, distribution, metabolism, and excretion (ADME).

AREAS COVERED

This review examines pharmacokinetic aspects of drug administration for adult intensive care unit (ICU) patients. Specifically, the authors examine the ADME changes that occur and which should be considered by clinicians when delivering drug therapy to critically ill patients.

EXPERT OPINION

Dosage pharmacokinetics determined from single-dose or limited-duration administration studies in healthy volunteers may not apply to critically ill patients. Organ dysfunction among these patients may be due to pre-existing disease or the effects of a systemic or locoregional inflammatory response precipitated by their illness. Alterations in pharmacokinetics observed among the critically ill include altered bioavailability after enteral administration, increased volume of distribution and blood-brain barrier permeability and changes in P-glycoprotein and cytochrome P450 enzyme function. However, the effect of these changes on clinically important outcomes remains uncertain and poorly studied. Future investigations should examine not only pharmacokinetic changes among the critically ill, but also whether recognition of these changes and alterations in drug therapy directed as a consequence of their observation alters patient outcomes.

Beneficial effect of splenic artery ligation on bacterial translocation after major liver resection in rats

OBJECTIVE

In major liver resection, bacterial translocation appears to be an important mechanism in the pathogenesis of spontaneous infection. This study was designed to investigate the effects of splenic artery ligation on bacterial translocation after major liver resection.

MATERIALS AND METHODS

Rats were divided into three groups: the sham operation group (SO group), the two-thirds partial hepatectomy group (PHx group) and the two-thirds partial hepatectomy plus splenic artery ligation group (PHx+Sp group). Bacterial translocation, endotoxemia, d-lactic acid and intestinal histology were analyzed among three groups.

RESULTS

The rate of bacterial translocation was higher in the PHx rats than in the SO rats (65.0% vs. 6.67%; P=0.001), so that in the PHx+Sp rats (25.0%; P=0.011). Endotoxemia was not evident in the SO rats (0pg/ml) and blood endotoxin levels decreased in the PHx+Sp rats (1.47pg/ml) compared with the PHx rats (4.05pg/ml, P<0.001). d-lactic acid was also higher in both the PHx and PHx+Sp rats compared with the SO rats (39.09mg/ml, 23.36mg/ml, and 1.68mg/ml; P<0.01).

CONCLUSION

Splenic artery ligation enhanced intestinal barrier function and diminished blood endotoxin levels and bacterial translocation in rats with major liver resection.

Reduction of intestinal mucosal immune function in heat-stressed rats and bacterial translocation

PURPOSE

The aim of this study was to further understand the effects and mechanism of heat stress on the intestinal mucosal immune system of the rat, including changes in the intestinal mucosal barrier and immune function and their effects on bacterial translocation.

MATERIALS AND METHODS

Sprague Dawley (SD) rats were randomly divided into control and heat-stress groups. Both groups were housed in a 25°C environment of 60% relative humidity. The heat-stress group was subjected to 40°C for 2 h daily over 3 days.

RESULTS

Compared with the control group villi length in the small intestines of the heat-stress group was shortened. Jejunal mucosa were seriously damaged and the number of goblet cells in the epithelia of the duodenum and jejunum was significantly reduced. Electron microscopy revealed intestinal mucosal disorder, a large number of exudates of inflammatory fibrous material, fuzzy tight junction structure between epithelial cells, and cell gap increases in the heat-stress group. Transcription of IFN-γ, IL-2, IL-4, and IL-10, was significantly reduced, as was that of the intestinal mucosal immune-related proteins TLR2, TLR4, and IgA. The number of CD3(+) T cells and CD3(+)CD4(+)CD8(-) T cells in the mesenteric lymph nodes (MLNs) was significantly lower, while the number of CD3(+)CD4(-)CD8(+) T cells was significantly increased. The bacteria isolated from the MLNs were Escherichia coli.

CONCLUSIONS

Heat stress damages rat intestinal mechanical and mucosal immune barriers, and reduces immune function of the intestinal mucosa and mesenteric lymphoid tissues, leading to bacterial translocation.

Enteral nutrition in the critically ill patient

Timing and route of nutrition provided to critically ill patients can affect their outcome. Early enteral nutrition has been shown to decrease specifically infectious morbidity in the critically ill patient. There is a small group of patients who are malnourished on arrival to the intensive care unit and in these patients parenteral nutrition is beneficial.

[Nutritional management of severely injured patients : Treatment between guidelines and reality]

Severe trauma triggers endocrine and inflammatory responses, leading to hyperglycaemia, insulin resistance and protein catabolism. Pharmacological and nutritional interventions cannot counteract these metabolic disturbances. However, adequate supply of energy and proteins may reduce excessive catabolism.Available guidelines recommend early use of enteral nutrition with energetic supply of about 25 kcal/kg and additional protein supply of 1.5 g/kg/day. These aims will be missed frequently by solely providing enteral nutrition in severely injured patients. Early supplemental parenteral nutrition should be used in these cases. Concomitantly, gastric paresis and paralytic ileus hampering enteral nutrition should be treated by propulsive and prokinetic drugs and by use of duodenal or jejunal site of application in selected cases.Euphoric hopes linked with intensified insulin therapy (IIT), targeting blood glucose levels <110 mg/dl in intensive care patients, had to be widely abandoned in recent years. The goal for blood glucose levels should be set at 180 mg/dl as the upper limit according to current knowledge, which promises to optimize the balance between efficacy and safety.

The GH/IGF-1 system in critical illness

The Growth Hormone and Insulin-like Growth Factor-1 (IGF-1) axis plays a pivotal role in critical illness, with a derangement leading to profound changes in metabolism. Protein wasting with skeletal muscle loss, delayed wound healing, and impaired recovery of organ systems are some of the most feared consequences. The use of human recombinant Growth Hormone (rhGH) and Insulin-like Growth Factor-1 (IGF-1) - alone and in combination - has been studied extensively in preclinical and clinical trials. This article reviews the current knowlegde and clinical practice of the use of rhGh and IGF-1 in critically ill patients, with a special focus on the trauma and burns patient population.

Effect of garlic oil on neutrophil infiltration in the small intestine of endotoxin-injected rats and its association with levels of soluble and cellular adhesion molecules

Garlic ( Allium sativum ) possesses anti-inflammatory effects. This study investigated the effects of garlic oil on endotoxin-induced neutrophil infiltration in the small intestine. Wistar rats received by gavage 10, 50, or 100 mg/kg body wt garlic oil (GO) or the vehicle (corn oil; 2 mL/kg body wt) every other day for 2 weeks before being injected with endotoxin (ip, 5 mg/kg body wt). Control rats were administered corn oil and injected with sterile saline. Blood samples for the measurement of soluble adhesion molecules were collected at various time points after injection, and all other samples were collected 18 h after injection. The 10 and 50 mg/kg doses suppressed endotoxin-induced neutrophilia, serum levels of sL-selectin and sICAM-1, cellular CD11b on neutrophils, intestinal ICAM-1 content, and neutrophil infiltration (P < 0.05). The 100 mg/kg dose significantly lowered local ICAM-1 and cellular CD11b on neutrophils (P < 0.05) but did not have a beneficial effect on neutrophil infiltration. In addition, 100 mg/kg of GO worsened the elevation of the local TNF-α level and neutrophilia. Appropriate doses of garlic oil have a preventive effect on endotoxin-induced neutrophil infiltration and damage to the small intestine.

Guidelines, guidelines, guidelines: what are we to do with all of these North American guidelines?

Over the past decade, clinical guidelines for nutrition therapy in the critically ill have been developed by different North American societies. To avoid target audience confusion and uncertainty, there is a need to undergo a review of the content of these guidelines. In this review, the authors compared the grading systems, the levels of evidence used, and the content of North American nutrition clinical guidelines. The 3 clinical guidelines that met their search criteria and hence were included in the comparison are the Canadian Clinical Practice Guidelines, the American Dietetics Association's evidence-based guideline for critical illness, and the Society of Critical Care Medicine and American Society of Parenteral and Enteral Nutrition's joint guideline. Through their comparison, the authors have shown that although there are several topics where there is a similar direction of recommendation across the 3 societies/organizations, there are stark contrasts among many of the recommendations. These major differences can be attributed to the admission of different populations, lower levels of evidence or expert opinion into the guideline production process, lack of clarity in the link between the evidence and the recommendation, and lack of uniformity in the reporting of levels of evidence and grades of recommendation. The authors have identified the need for the North American nutrition organizations to harmonize the development of future nutrition guidelines in a timely way, so that they remain current and up-to-date. Furthermore, guideline users need to be aware of the dissimilarities in these guidelines before applying the recommendations to their daily practice.

Insulin-like growth factor-1 levels contribute to the development of bacterial translocation in sepsis

RATIONALE

Many lines of evidence point toward the gastrointestinal (GI) tract in the pathophysiology of organ dysfunction in sepsis. Splanchnic hypoperfusion during sepsis leads to enterocyte apoptosis, diminished barrier function, and release of bacterial products. Sepsis lowers levels of insulin-like growth factor (IGF)-1, a known antiapoptotic factor. We recently demonstrated that treatment with IGF-1 is protective in murine sepsis.

OBJECTIVES

We hypothesize that decreased IGF-1 levels in sepsis contributes to the development of bacterial translocation.

METHODS

Sepsis was induced in C57BL/6 mice via intratracheal instillation of Pseudomonas aeruginosa. Human subjects with sepsis were enrolled if they had a documented positive blood culture with a nonenteric organism. Bacterial translocation was measured in serum by quantitative real-time polymerase chain reaction with primers specific for enteric bacteria. Serum IGF-1 was measured by ELISA. Apoptosis of the GI epithelium was assessed via immunohistochemistry.

MEASUREMENTS AND MAIN RESULTS

We found that mice with severe sepsis had evidence of bacterial translocation by 24 hours. Enteric bacterial load correlated inversely with levels of serum IGF-1. If we treated mice with IGF-1, bacterial translocation was significantly decreased. In addition, we found increased GI epithelial cell apoptosis after sepsis, which was significantly decreased after IGF-1 treatment. Human subjects with nonenteric sepsis developed progressive enteric bacteremia over 3 days. The degree of enteric bacteremia correlated inversely with serum IGF-1 levels.

CONCLUSIONS

These data support the hypothesis that sepsis-induced reductions in IGF-1 levels contribute to the development of bacterial translocation in both a murine model and human subjects.

Understanding the mechanisms of glutamine action in critically ill patients

Glutamine (Gln) is an important energy source and has been used as a supplementary energy substrate. Furthermore, Gln is an essential component for numerous metabolic functions, including acid-base homeostasis, gluconeogenesis, nitrogen transport and synthesis of proteins and nucleic acids. Therefore, glutamine plays a significant role in cell homeostasis and organ metabolism. This article aims to review the mechanisms of glutamine action during severe illnesses. In critically ill patients, the increase in mortality was associated with a decreased plasma Gln concentration. During catabolic stress, Gln consumption rate exceeds the supply, and both plasma and skeletal muscle pools of free Gln are severely reduced. The dose and route of Gln administration clearly influence its effectiveness: high-dose parenteral appears to be more beneficial than low-dose enteral administration. Experimental studies reported that Gln may protect cells, tissues, and whole organisms from stress and injury through the following mechanisms: attenuation of NF (nuclear factor)-kB activation, a balance between pro- and anti-inflammatory cytokines, reduction in neutrophil accumulation, improvement in intestinal integrity and immune cell function, and enhanced of heat shock protein expression. In conclusion, high-doses of parenteral Gln (>0.50 g/kg/day) demonstrate a greater potential to benefit in critically ill patients, although Gln pathophysiological mechanisms requires elucidation.

Clinical trial: prophylactic intravenous alanyl-glutamine reduces the severity of gastrointestinal toxicity induced by chemotherapy--a randomized crossover study

BACKGROUND

Glutamine has been shown in numerous studies to reduce intestinal permeability which can be increased by chemotherapy. However, there have been few reports that conduct on its clinical effect on gastrointestinal toxicity.

AIM

To examine whether prophylactic intravenous alanyl-glutamine dipeptide can ameliorate clinical manifestations of gastrointestinal toxicity induced by chemotherapy.

METHODS

Forty-four patients with gastric or colorectal cancer developing WHO side-effect grading system of grade 2 or higher were randomized to either control group (n = 22) or Gln group (n = 22) during next cycle of chemotherapy. Patients were crossed over to the alternate treatment during chemotherapy cycle 2. In the control group, the patients received the same chemotherapy regimens as screening cycle and in the Gln group, the patients received chemotherapy and alanyl-glutamine. Prophylactic intravenous 20 g of alanyl-glutamine dipeptide was given for 5 days.

RESULTS

Compared with the control group, the plasma glutamine level in the Gln group was significantly higher and the plasma endotoxin level was significantly lower. The scores of nausea/vomiting and diarrhoea decreased significantly.

CONCLUSION

Prophylactic intravenous alanyl-glutamine is effective in preventing intestinal permeability disruption induced by chemotherapy and clinical manifestations of gastrointestinal toxicity.

Total Enteral Nutrition Facilitates Wound Healing Through Preventing Intestinal Atrophy, Keeping Protein Anabolism and Suppressing Inflammation

Background

In clinical settings, early total enteral nutrition (TEN) is known to reduce the postoperative complication and infection rate as well as duration of postoperative stay compared with total parenteral nutrition (TPN) in a variety of critical conditions. We aimed to compare effects TEN and TPN on wound healing and explore its possible mechanisms using rat model.

Methods

Seven days after operation for inserting enteral tube into gastric space for TEN, Sprague-Dawley rats were made burn (15 mm) in the back. Rats were administrated with either TEN (N = 17) or TPN (N = 15) and evaluated condition of wound healing as well as serum/urine immunological and biochemical parameters at 28 days.

Results

Burned area was significantly reduced in TEN than in TPN group. Although body weight, serum levels of total protein, albumin and transferrin were the same levels between the two groups, urine nitrogen and intestinal atrophy were significant in TPN group. Conversely, weight of small bowel showed positive linear relationship with levels of parameters calculated as follows: [medication nitrogen quantity – (urine nitrogen + feces nitrogen)]/[medication nitrogen – feces nitrogen quantity]. Weights of spleen and tumor necrotizing factor-a levels in serum were higher in TPN than in TEN.

Conclusions

These results suggest that TEN may facilitate wound healing compared with TPN through preventing intestinal atrophy, keeping protein anabolism and suppressing inflammation.

Nutrition intervention: a strategy against systemic inflammatory syndrome

BACKGROUND

Sepsis and septic shock syndrome are the leading causes of death in critically ill patients. Lipopolysaccharide (LPS) released by the colonic microorganisms may translocate across a compromised lumen, leading to upregulated reactive oxidative stress, inflammation, and sepsis. The authors examined an enteral formula high in cysteine (antioxidant precursor), omega-3 fatty acids, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), and prebiotic fructooligosaccharides (FOS) against systemic inflammatory syndrome.

METHODS

Rats were allocated to (1) standard soy-based diet high in cysteine and crude fiber and devoid of EPA-DHA (CHOW); (2) whey-peptide-based liquid diet high in cysteine, EPA-DHA, and FOS (CYSPUFA); or (3) casein-based liquid isonitrogenous diet, low in cysteine and devoid of EPA-DHA-FOS (CASN). Liquid diets provided 25% and CHOW, 23% of calories as protein. After 6 days on diets, rats received an intraperitoneal injection of LPS or saline. Animals gained weight on their respective diets and lost weight after LPS administration. The CYSPUFA group lost considerably less weight (vs CASN or CHOW, P < .05). Inflammatory cytokines significantly increased by 4 hours and subsided 18 hours after assault. The CASN group showed elevated liver enzyme alanine aminotransferase release from damaged hepatocytes and developed severe hepatic pathology with low hematocrit. The CHOW group developed more severe hepatic lesions compared with those on liquid diets. Concentration of liver enzyme and pathology were improved in rats receiving CYSPUFA.

CONCLUSIONS

Data indicate that CYSPUFA, a diet rich in EPA-DHA-FOS, protects against LPS-induced systemic inflammatory responses and warrants clinical studies in critically ill patients.