Enteral versus parenteral nutrition: the significance of bacterial translocation and gut-barrier function

Usefulness of Perioperative Nutritional Therapy with the Glutamine/Arginine/Calcium β-Hydroxy-β-Methylbutyrate Product in Esophageal Cancer Surgery: A Single-Center Retrospective Study

A useful perioperative nutritional therapy for highly invasive esophageal cancer surgical cases needs to be developed. We clarified the usefulness of amino-acid-enriched nutritional therapy using glutamine (Gln)/arginine (Arg)/calcium β-hydroxy-β-methylbutyrate (HMB) products on the short-term postoperative outcomes of minimally invasive esophagectomy for esophageal cancer. Altogether, 114 patients (Gln/Arg/HMB group) received perioperative nutritional therapy with Gln/Arg/HMB products, and we retrospectively investigated the change in nutritional parameters including skeletal muscle mass, occurrence of postoperative complications, and short-term postoperative outcomes in this group. The results were compared between the Gln/Arg/HMB and control groups (79 patients not receiving the Gln/Arg/HMB products). The incidence of all postoperative complications, sputum expectoration disorder, and pleural effusion of grade ≥ III was significantly lower in the Gln/Arg/HMB group (62.0% vs. 38.6%, p = 0.001; 44.3% vs. 28.1%, p = 0.020; 27.8% vs. 13.2%, p = 0.011, respectively). The psoas muscle area and postoperative body weight were significantly higher at 1 month and 1 year after surgery in the Gln/Arg/HMB group than in the control group (93.5% vs. 99.9%, p < 0.001; 92.0% vs. 95.4%, p = 0.006). Perioperative amino-acid-enriched nutritional therapy may improve the short-term postoperative outcomes, nutritional status, and skeletal muscle mass of esophageal cancer surgical patients.

The role of gut barrier dysfunction in postoperative complications in liver transplantation: pathophysiological and therapeutic considerations

PURPOSE

Gut barrier dysfunction is a pivotal pathophysiological alteration in cirrhosis and end-stage liver disease, which is further aggravated during and after the operational procedures for liver transplantation (LT). In this review, we analyze the multifactorial disruption of all major levels of defense of the gut barrier (biological, mechanical, and immunological) and correlate with clinical implications.

METHODS

A narrative review of the literature was performed using PubMed, PubMed Central and Google from inception until November 29th, 2023.

RESULTS

Systemic translocation of indigenous bacteria through this dysfunctional barrier contributes to the early post-LT infectious complications, while endotoxin translocation, through activation of the systemic inflammatory response, is implicated in non-infectious complications including renal dysfunction and graft rejection. Bacterial infections are the main cause of early in-hospital mortality of LT patients and unraveling the pathophysiology of gut barrier failure is of outmost importance.

CONCLUSION

A pathophysiology-based approach to prophylactic or therapeutic interventions may lead to enhancement of gut barrier function eliminating its detrimental consequences and leading to better outcomes for LT patients.

The Impact of Nutritional Therapy on Gastrointestinal Motility in Older Adults

Japan is becoming a superaged society, and nutrition therapy for the elderly population is very important. Elderly individuals often have multiple diseases and are prone to malnutrition. Furthermore, functional constipation, diarrhoea, faecal incontinence, etc., may occur despite no organic abnormality of digestive tract function. Due to these disabilities, the resulting malnutrition, and the slow recovery, it is often difficult for elderly individuals to reintegrate into society. Secondary or incorrect nutritional management increases complications, decreases physical function and worsens the prognosis. Previous statistical research suggests that in-hospital mortality is significantly higher among hospitalised patients aged ≥65 years who ingest less than half of their caloric needs. Therefore, appropriate nutritional management from an early stage is essential for elderly individuals. Moreover, functional excretion disorders, dementia, and sarcopenia (muscle-wasting disease) are attracting attention as pathological conditions unique to elderly individuals, and it is essential to undergo rehabilitation early with nutritional management. Being elderly does not preclude nutritional management, and it is necessary to reconsider appropriate nutritional therapy even in the terminal stage and in advanced physical and mental illnesses. This review explores the relationship between dietary intake and FGIDs, with a focus on elderly adults.

Long-term prognosis of enteral feeding and parenteral nutrition in a population aged 75 years and older: a population-based cohort study

Background

Enteral feeding and parenteral nutrition (PN) using gastrostomy (GS) and a nasogastric tube feeding (NGT) and PN should be initiated for older patients based on their prognoses. This study aimed to investigate the long-term prognosis of patients aged ≥75 years who underwent enteral feeding via GS and NGT as well as PN.

Methods

A population-based cohort study was conducted using Japan’s universal health insurance claims in the Nara Prefecture. This study enrolled 3,548 patients aged ≥75 years who received GS (N=770), NGT (N=2,370), and PN (N=408) during hospital admissions between April 2014 and March 2016. The GS group was further categorized into secondary GS (N=400) with preceding NGT or PN within 365 days and primary GS (N=370) without preceding NGT or PN groups. In the secondary GS group, 356 (96%) patients received NGT (versus PN). The outcome was mortality within 730 days after receiving GS, NGT, and PN. Cox regression analyses in cases with or without malignant diseases, adjusted for sex, age, comorbidity, and hospital type, were performed to compare mortality in the groups.

Results

Of the 3,548 participants, 2,384 (67%) died within 730 days after the initiation of GS and NGT and PN. The 2-year mortality rates in the secondary GS, primary GS, NGT, and PN groups were 58%, 66%, 68%, and 83% in patients without malignancies and 67%, 71%, 74%, and 87% in those with malignancies, respectively. In the non-malignant group, Cox regression analysis revealed that secondary GS (hazard ratio (HR) = 0.43, 95% CI: 0.34–0.54), primary GS (HR = 0.51, 95% CI: 0.40–0.64), and NGT (HR = 0.71, 95% CI: 0.58-0.87) were statistically significantly associated with lower mortality compared with PN.

Conclusions

Approximately 58% to 87% patients aged ≥75 years died within 730 days after initiation of nutrition through GS, NGT, or PN. Patients with non-malignant diseases who received secondary GS exhibited better 2-year prognosis than those who received NGT or PN. Healthcare professionals should be aware of the effectiveness and limitations of enteral feeding and PN when considering their initiation.

Effects of Dietary Isomaltooligosaccharide Levels on the Gut Microbiota, Immune Function of Sows, and the Diarrhea Rate of Their Offspring

To investigate the effects of dietary isomaltooligosaccharide (IMO) levels on the gut microbiota, immune function of sows, and the diarrhea rate of their offspring, 120 multiparous gestating pig improvement company (PIC) sows with similar body conditions were selected and fed 1 of 6 diets: a basal diet with no supplement (control, CON), or a diet supplemented with 2.5 g/kg, 5.0 g/kg, 10.0 g/kg, 20.0 g/kg, or 40.0 g/kg IMO (IMO1, IMO2, IMO3, IMO4, or IMO5 group, respectively). Results showed that dietary treatments did not affect the reproductive performance and colostrum composition of sows (P > 0.05). However, compared to the CON, IMO reduced the diarrhea rate of suckling piglets (P < 0.05) and improved the concentrations of colostrum IgA, IgG, and IgM (P < 0.05). Moreover, IMO decreased the concentrations of serum D-lactate (D-LA) and lipopolysaccharides (LPS) at farrowing and day 18 of lactation (L18) (P < 0.05). High-throughput pyrosequencing of the 16S rRNA demonstrated that IMO shaped the composition of gut microbiota in different reproductive stages (day 107 of gestation, G107; day 10 of lactation, L10) (P < 0.05). At the genus level, the relative abundance of g_Parabacteroides and g_Slackia in G107 and g_Unclassified_Peptostreptococcaceae, g_Turicibacter, g_Sarcina, and g_Coprococcus in L10 was increased in IMO groups but the g_YRC22 in G107 was decreased in IMO groups relative to the CON group (P < 0.05). Furthermore, the serum D-LA and LPS were negatively correlated with the genus g_Akkermansia and g_Parabacteroides but positively correlated with the genus g_YRC22 and g_Unclassified_Peptostreptococcaceae. Additionally, the colostrum IgA, IgG, and IgM of sows were positively correlated with the genus g_Parabacteroides, g_Sarcina, and g_Coprococcus but negatively correlated with the genus g_YRC22. These findings indicated that IMO could promote the immune activation and had a significant influence in sows' gut microbiota during perinatal period, which may reduce the diarrhea rate of their offspring.

Protective effect of extracorporeal membrane oxygenation on intestinal mucosal injury after cardiopulmonary resuscitation in pigs

The present study aimed to explore the protective effects of extracorporeal membrane oxygenation (ECMO) on intestinal mucosal injury following cardiopulmonary resuscitation (CPR), and to assess the potential mechanisms involved. A total of 24 healthy adult domestic pigs were selected as the study subjects. A ventricular fibrillation model was induced through programmed electric stimulation. Subsequently, the animals were randomly divided into conventional CPR and CPR+ECMO groups (n=12 per group). The mortality and hemodynamic parameters of the two groups were compared. The expression levels of inflammatory cytokines in the serum and intestinal mucosa were detected by ELISAs. The intestinal mucosa was subjected to hematoxylin and eosin, and immunohistochemical staining, followed by electron microscopy, to assess the degree of apoptosis and necrosis. The animals in both groups recovered from the programmed ventricular fibrillation. In the CPR group, two animals died at 2 h and two more animals died a further 2 h later, resulting in a 33.3% mortality rate, whereas no cases of mortality were observed in the CPR+ECMO group. Compared with the animals in the CPR group, the hemodynamic parameters of the animals in the CPR+ECMO group revealed significantly improved outcomes. Multiple inflammatory factors (tumor necrosis factor α, interleukin-1 and interleukin-6), myeloperoxidase and malondialdehyde levels were decreased, whereas Na/Ca-ATPase and superoxide dismutase levels were elevated in the intestinal mucosa of animals in the CPR+ECMO group compared with those in the CPR group. Additionally, pathological staining demonstrated that the intestinal mucosa tissue in the CPR+ECMO group exhibited less apoptosis, necrosis and inflammatory cell infiltration, which was further supported by a decrease in Bax expression and an increase in Bcl-2 expression. Overall, ECMO after CPR reduced the intestinal mucosal barrier injury after spontaneous circulation recovery, and the mechanism involved decreased inflammation and apoptosis.

Comparison of long-term outcomes between enteral nutrition via gastrostomy and total parenteral nutrition in older persons with dysphagia: A propensity-matched cohort study

Background

The long-term outcomes of artificial nutrition in older people with dysphagia remain uncertain. Enteral nutrition via percutaneous endoscopic gastrostomy (PEG) is one of the major methods of artificial nutrition. Enteral feeding is indicated for patients with a functional gastrointestinal tract. However, total parenteral nutrition (TPN) is often inappropriately chosen for artificial nutrition in Japan, even in patients with a functional gastrointestinal tract, as PEG has recently been viewed as an unnecessary life-prolonging treatment in Japan. This study aimed to compare the long-term outcomes between PEG and TPN.

Methods

This single-center retrospective cohort study investigated long-term outcomes in older patients with dysphagia who received PEG or TPN between January 2014 and January 2017. The primary outcome was survival time. Secondary outcomes were oral intake recovery, discharge to home, and the incidence of severe pneumonia and sepsis. We performed 1-to-1 propensity score matching using a 0.05 caliper. The Kaplan–Meier method, log-rank test, and Cox regression analysis were used to compare the survival time between groups.

Results

We identified 253 patients who received PEG (n = 180) or TPN (n = 73). Older patients, those with lower nutritional states, and severe dementia were more likely to receive TPN. Propensity score matching created 55 pairs. Survival time was significantly longer in the PEG group (median, 317 vs 195 days; P = 0.017). The hazard ratio for PEG relative to TPN was 0.60 (95% confidence interval: 0.39–0.92; P = 0.019). There were no significant differences between the groups in oral intake recovery and discharge to home. The incidence of severe pneumonia was significantly higher in the PEG group (50.9% vs 25.5%, P = 0.010), whereas sepsis was significantly higher in the TPN group (10.9% vs 30.9%, P = 0.018).

Conclusions

PEG was associated with a significantly longer survival time, a higher incidence of severe pneumonia, and a lower incidence of sepsis compared with TPN.

What do we know about optimal nutritional strategies in children with pediatric acute respiratory distress syndrome?

Nutrition in pediatric acute respiratory distress syndrome (PARDS) is an essential aspect of therapy, with potential to modify outcomes. The gut is slowly establishing its place as the motor of critical illness, and the 'gut-lung' axis has been shown to be in play in the systemic inflammatory response. Thus, utilizing the gut to modify outcomes in PARDS is an exciting prospect. PARDS is associated with high mortality in low- and middle-income countries (LMIC), where malnutrition is also prevalent and may worsen during hospital stay. Mortality may be higher in this subgroup of patients. At present, the gold standard to estimate resting energy expenditure (REE) in critically ill children is indirect calorimetry. However, it is a cumbersome and expensive procedure, as a result of which its routine practice is limited to very few units across the world. Therefore, predictive equations, which may under- or over-estimate REE, are relied upon to approximate calorie and protein needs of children with PARDS. Despite having target calorie and protein requirements, studies have found that a large proportion of critically ill children do not achieve these levels even at the end of a week in pediatric intensive care unit (PICU). The preferred mode of nutrition delivery is enteral, and if possible, early enteral nutrition (EEN). Immunonutrition has been a lucrative subject of research, and while there have been some strides, no therapy has yet conclusively demonstrated benefit in terms of mortality or reduced length of stay in PICU or the hospital. Probable immunonutrients in PARDS include omega-3 fatty acids, arginine, glutamine and vitamin D, though none are a part of any recommendations yet.

The Role of Liver Transplantation in Alcoholic Hepatitis

Acute alcoholic hepatitis is a syndrome of jaundice and hepatic decompensation that occurs with excessive alcohol consumption. The diagnosis can be made with a combination of clinical characteristics and laboratory studies, though biopsy may be required in unclear cases. Acute alcoholic hepatitis can range from mild to severe disease, as determined by a Maddrey discriminant function ≥32. Mild forms can be managed with supportive care and abstinence from alcohol. While mild form has an overall good prognosis, severe alcoholic hepatitis is associated with an extremely high short-term mortality of up to 50%. Additional complications of severe alcoholic hepatitis can include hepatic encephalopathy, gastrointestinal bleeding, renal failure, and infection; these patients frequently require intensive care unit admission. Corticosteroids may have short-term benefit in this group of patients if there are no contraindications; however, a subset of patients do not respond to steroids. New emerging therapies, which target hepatic regeneration, bile acid metabolism, and extracorporeal liver support, are being investigated. Liver transplantation for alcoholic liver disease was traditionally only considered in patients who have achieved 6 months of abstinence, in part due to social and ethical concerns regarding the use of a limited resource. However, the majority of patients with severe alcoholic hepatitis who fail medical therapy will not live long enough to meet this requirement. Recent studies have demonstrated that early liver transplantation in carefully selected patients with severe alcoholic hepatitis who fail medical therapy can provide a significant survival benefit and yields survival outcomes comparable to liver transplantation for other indications, with 6-month survival rates ranging from 77% to 100%. Alcohol relapse posttransplantation remains an important challenge, and heavy consumption can contribute to graft loss and mortality. Future investigation should address the substantial post-liver transplantation recidivism rate, from improving selection criteria to increasing posttransplantation substance abuse treatment resources.

Acute Alcoholic Hepatitis

Alcoholic hepatitis is a unique type of alcohol-associated liver disease characterized by acute liver inflammation caused by prolonged heavy alcohol use. Treatment is mostly supportive. The short-term prognosis of acute alcoholic hepatitis depends on liver recovery, and ranges widely from rapid improvement to grim multiorgan failure despite treatment. Refinement of scoring systems have enhanced prognostication to guide clinical decision making in alcoholic hepatitis. Recent advances in the treatment of alcoholic hepatitis have solidified corticosteroids as the cornerstone of treatment to enhance short-term survival, but not intermediate or long-term survival.

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.

Role of liver transplantation in severe alcoholic hepatitis

Severe alcoholic hepatitis has very high short term mortality and corticosteroids have been the mainstay of treatment for decades. Patients with Lille score >0.45 are considered non-responders to steroids and have poor outcome. Recently Orthotopic Liver Transplantation (OLT) is being increasingly used as rescue treatment for these patients, without waiting for 6 months of abstinence. Liver transplant is the only rescue treatment which can potentially provide long term benefit for patients who are steroid non-responders. However, with scarcity of organs being a concern, all patients of severe alcoholic hepatitis cannot be chosen for transplantation in an arbitrary way. There is a need for development of predictive tools and objective protocols to select patients who can justify the use of precious liver grafts. With a stringent criteria for selection of patients receiving the graft, liver transplantation in severe alcoholic hepatitis can become a viable rescue therapeutic option conferring significant survival advantage of both short- and long-term basis. The optimal criteria for selection will also prevent misuse of the liver donor pool as well as to prevent mortality in salvageable patients. Further research needs to be done to identify subset of patients which are at low risk of recidivism and also cannot be managed with pharmacotherapy alone. We reviewed the current knowledge on role of OLT in patient with acute severe alcoholic hepatitis in the present review.

The role of the sensor kinase, QseC, an adrenergic receptor of Escherichia coli, in bacterial translocation during hemorrhagic shock

BACKGROUND

Hemorrhagic shock results in ileal mucosa damage and intestinal bacterial translocation. Additionally, during hemorrhagic shock, norepinephrine levels increase. Past research has shown that the QseC sensor kinase of Escherichia coli modulates the quorum-sensing response to epinephrine and norepinephrine. Therefore, the aim of our study was to examine whether the absence of the ability of E. coli to sense epinephrine/norepinephrine would attenuate the bacterial translocation to extraintestinal organs in a rat model of hemorrhagic shock.

METHODS

An E. coli MC1000 qseC mutant was constructed, and E. coli MC1000 and MC1000ΔqseC with streptomycin resistance were used to track bacterial translocation after gavage in rats. A rat model of nonlethal hemorrhagic shock was used. The rats were divided into six groups: controls (SS), rats that received a sham shock and MC1000 (M-SS), rats that received a sham shock and MC1000ΔqseC (Δ-SS), rats that received a hemorrhagic shock alone (HS), rats that received a hemorrhagic shock and MC1000 (M-HS), and rats that received a hemorrhagic shock and MC1000ΔqseC (Δ-HS).

RESULTS

We found the incidence of bacterial translocation in the M-HS rats was higher than in the Δ-HS rats. The observed effects seem to be largely dependent on the inability to sense epinephrine/norepinephrine and the decreased motility of E. coli MC1000ΔqseC.

CONCLUSION

Therefore, a role for E. coli sensing epinephrine/norepinephrine in the pathophysiology of bacterial translocation following hemorrhagic shock is proposed. The demonstration of such an effect would suggest a new mechanism for the development of shock-induced sepsis.

Pediatric Multiple Organ Dysfunction Syndrome: Promising Therapies

OBJECTIVE

To describe the state of the science, identify knowledge gaps, and offer potential future research questions regarding promising therapies for children with multiple organ dysfunction syndrome presented during the Eunice Kennedy Shriver National Institute of Child Health and Human Development Workshop on Pediatric Multiple Organ Dysfunction Syndrome (March 26-27, 2015).

DATA SOURCES

Literature review, research data, and expert opinion.

STUDY SELECTION

Not applicable.

DATA EXTRACTION

Moderated by an expert from the field, issues relevant to the association of multiple organ dysfunction syndrome with a variety of conditions were presented, discussed, and debated with a focus on identifying knowledge gaps and research priorities.

DATA SYNTHESIS

Summary of presentations and discussion supported and supplemented by relevant literature.

CONCLUSIONS

Among critically ill children, multiple organ dysfunction syndrome is relatively common and associated with significant morbidity and mortality. For outcomes to improve, effective therapies aimed at preventing and treating this condition must be discovered and rigorously evaluated. In this article, a number of potential opportunities to enhance current care are highlighted including the need for a better understanding of the pharmacokinetics and pharmacodynamics of medications, the effect of early and optimized nutrition, and the impact of effective glucose control in the setting of multiple organ dysfunction syndrome. Additionally, a handful of the promising therapies either currently being implemented or developed are described. These include extracorporeal therapies, anticytokine therapies, antitoxin treatments, antioxidant approaches, and multiple forms of exogenous steroids. For the field to advance, promising therapies and other therapies must be assessed in rigorous manner and implemented accordingly.

Effects of weaning on intestinal crypt epithelial cells in piglets

Intestinal epithelial cells in the crypt proliferate in piglets in response to weaning. However, the underlying mechanism has been unclear. We examined 40 piglets from eight litters (five piglets per litter) that were weaned at the age of 14 d, and one piglet from each litter was randomly selected for closer investigation. Based on the distended intestinal sac method, we isolated crypt epithelial cells from the mid-jejunum on Days 0, 1, 3, 5, and 7 post-weaning. Protein expression was analyzed using either isobaric tags for relative and absolute quantification or western blotting. Proteins related to the cell cycle, organization of the cellular macromolecular complex subunit, localization of cellular macromolecules, Golgi vesicle transport, fatty acid metabolism, oxidative phosphorylation, and translational initiation were mainly down-regulated, while those involved in glycolysis, cell cycle arrest, protein catabolism, and cellular amino acid metabolism were up-regulated. The amount of proteins active in the mTOR signaling pathway was generally decreased over time. These results indicate that weaning influences energy metabolism, cellular macromolecule organization and localization, and protein metabolism, thereby affecting the proliferation of intestinal epithelial cells in weaned piglets. Moreover, those cellular processes are possibly controlled by that signaling pathway.

Early enteral nutrition improves intestinal immune barrier in a rat model of severe acute pancreatitis

BACKGROUND

The aim of the present study was to investigate the role of early enteral nutrition (EEN) in the intestinal immune barrier in severe acute pancreatitis (SAP), and to explore its potential mechanisms.

METHODS

Sixty rats were randomly assigned to three groups: sham-operated group (SO group, n = 20), SAP group receiving EEN (SAP + EEN group, n = 20), and SAP group receiving total parental nutrition (SAP + TPN group, n = 20). SAP was induced by infusion of sodium taurocholate. Rats were killed 5 days after nutritional support. The pathological damage of the intestine was determined using HE staining. The expression of MAdCAM-1, CD⁴⁺ , and CD⁸⁺ in Peyer's lymph nodes of the distal ilium was examined by immunohistochemistry. Serum levels of endotoxin and bacterial translocation were determined.

RESULTS

The survival rate in the SAP + TPN (50%) and SAP + EEN (75%) groups was significantly lower than in the SO group (100%) (P < 0.05). The survival rate in the SAP + EEN group was significantly higher than in the SAP + TPN group (P < 0.05). The expression of MAdCAM-1, CD⁴⁺ and CD⁸⁺ in the intestine was decreased in SAP rats. EEN significantly increased the expression of MAdCAM-1, CD⁴⁺ and CD⁸⁺ compared with TPN, accompanied by a decrease in the serum levels of endotoxin and bacterial translocation.

CONCLUSIONS

Early enteral nutrition improves intestinal immune barrier, thus reducing bacterial and endotoxin translocation and improving the survival rate in SAP rats.

Nonpulmonary treatments for pediatric acute respiratory distress syndrome: proceedings from the Pediatric Acute Lung Injury Consensus Conference

OBJECTIVE

To describe the recommendations from the Pediatric Acute Lung Injury Consensus Conference on nonpulmonary treatments in pediatric acute respiratory distress syndrome.

DESIGN

Consensus conference of experts in pediatric acute lung injury.

METHODS

A panel of 27 experts met over the course of 2 years to develop a taxonomy to define pediatric acute respiratory distress syndrome and to make recommendations regarding treatment and research priorities. The nonpulmonary subgroup comprised three experts. When published data were lacking, a modified Delphi approach emphasizing strong professional agreement was utilized.

RESULTS

The Pediatric Acute Lung Injury Consensus Conference experts developed and voted on a total of 151 recommendations addressing the topics related to pediatric acute respiratory distress syndrome, 30 of which related to nonpulmonary treatment. All 30 recommendations had strong agreement. Patients with pediatric acute respiratory distress syndrome should receive 1) minimal yet effective targeted sedation to facilitate mechanical ventilation; 2) neuromuscular blockade, if sedation alone is inadequate to achieve effective mechanical ventilation; 3) a nutrition plan to facilitate their recovery, maintain their growth, and meet their metabolic needs; 4) goal-directed fluid management to maintain adequate intravascular volume, end-organ perfusion, and optimal delivery of oxygen; and 5) goal-directed RBC transfusion to maintain adequate oxygen delivery. Future clinical trials in pediatric acute respiratory distress syndrome should report sedation, neuromuscular blockade, nutrition, fluid management, and transfusion exposures to allow comparison across studies.

CONCLUSIONS

The Consensus Conference developed pediatric-specific definitions for pediatric acute respiratory distress syndrome and recommendations regarding treatment and future research priorities. These recommendations for nonpulmonary treatment in pediatric acute respiratory distress syndrome are intended to promote optimization and consistency of care for patients with pediatric acute respiratory distress syndrome and identify areas of uncertainty requiring further investigation.

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.

Early enteral nutrition improves intestinal barrier function in rats with severe acute pancreatitis

AIM: To investigate the effect of early enteral nutrition on the intestinal barrier function in rats with severe acute pancreatitis (SAP).

METHODS: Sixty male Sprague-Dawley rats were randomly allocated into 4 groups: a sham-operation group (n = 15), an SAP group (control group, n =15), a parenteral nutrition group (PN group, n = 15) and an enteral nutrition group (EN group, n = 15). SAP was induced by retrograde injection of 5% sodium taurocholate into the biliopancreatic duct. Rats in the sham-operation group only underwent laparotomy without induction of SAP. Six hours after surgery, rats in the former two groups were given normal saline, while those in the latter two groups were administrated with EN and PN, respectively. All rats were sacrificed 48 h after operation. Serum levels of amylase (AMS), endotoxin and diamine oxidase (DAO) were detected. Pathological changes of the pancreas were observed by light microscopy. The incidence of pancreatic abscess was calculated. The sections of terminal ileum were obtained to measure the height of villi and the thickness of the mucosa.

RESULTS: Plasma levels of endotoxin and DAO were significantly lower in the EN group than in the SAP group and PN group (endotoxin: 0.247 EU/mL ± 0.069 EU/mL vs 0.545 EU/mL ± 0.095 EU/mL, 0.333 EU/mL ± 0.046 EU/mL; P < 0.05 for the PN group, P < 0.01 for the SAP group; DAO: 0.91 EU/mL ± 0.13 EU/mL vs 1.52 U/mL ± 0.09 U/mL, 1.17 U/mL ± 0.10 U/mL; P < 0.01 for both). There were no significant differences in plasma amylase (AMS) between the SAP group, EN group and PN group (10171 U/L ± 665.77 U/L vs 9428.2 U/L ± 1076.61 U/L vs 10533 U/L ± 1669.13 U/L). The histological score of the injured pancreas in the EN group was markedly decreased in comparison with those in the SAP group and PN group (8.08 ± 1.24 vs 14.50 ± 1.05, 10.44 ± 1.01; P < 0.01 for both). The rate of pancreatic abscess in the three groups was not statistically different (SAP group: 9/15, EN group: 2/15, PN group: 6/15). Compared with the SAP group, the thickness of the mucosa and height of villi were improved obviously in both the EN group and PN group (thickness of mucosa: 226.67 µm ± 20.84 µm vs 294.79 µm ± 20.49 µm, 306.11 µm ± 24.34 µm; P < 0.01 for both; height of villi: 137.33 µm ± 9.38 µm vs 194.54 µm ± 11.96 µm, 201.72 µm ± 10.60 µm; P < 0.01 for both), although there was no significant difference between the EN group and PN group.

CONCLUSION: Early enteral nutrition can significantly improve the gut barrier function and ameliorate intestinal endotoxemia in rats with SAP.

The detection of intraoperative bacterial translocation in the mesenteric lymph nodes is useful in predicting patients at high risk for postoperative infectious complications after esophagectomy

OBJECTIVE

To investigate the incidence of BT in the mesenteric lymph node and bacteremia after an esophagectomy using a bacterium-specific ribosomal RNA-targeted reverse-transcriptase quantitative polymerase chain reaction (RT-qPCR).

BACKGROUND

There is little evidence regarding the occurrence of bacterial translocation (BT) and its correlation to postoperative infectious complications after an esophagectomy.

METHODS

Eighteen patients with esophageal cancer were studied. Mesenteric lymph nodes were harvested from the jejunal mesentery before surgical mobilization (MLN-1) and after the restoration of bowel continuity (MLN-2). Blood and sputum were also sampled before surgery (Blood-1 and Sputum-1) and on postoperative day 1 (Blood-2 and Sputum-2).

RESULTS

The detection rates of bacteria in the MLN-2 (56%) and Blood-2 (56%) were significantly higher than those in the MLN-1 (17%) and Blood-1 (22%), indicating that surgical stress induces BT. The detection rate was not different between Sputum-1 (80%) and Sputum-2 (78%). There was an 80% sequence homology between the RT-qPCR products in the MLN-2 and Blood-2, whereas the homology was only 20% between Blood-2 and Sputum-2. In the patients with positive bacteria in the MLN-2 sample, there was a greater incidence of postoperative infectious complications than in patients without bacteria in the MLN-2 sample (P = 0.04). The postoperative hospital stay was also longer (P = 0.037) for patients with positive bacteria in the MLN-2 sample.

CONCLUSIONS

BT frequently occurs during esophagectomies, and postoperative bacteremia is likely to be gut-derived. Patients with positive bacteria in the MLN-2 sample should be carefully managed because these patients are more susceptible to postoperative infectious complications.

Prospective cohort study comparing the effects of different artificial nutrition methods on long-term survival in the elderly: Japan Assessment Study on Procedures and Outcomes of Artificial Nutrition (JAPOAN)

BACKGROUND

The effects of various artificial nutrition methods on the long-term outcomes of elderly patients are still not well known. We aimed to compare the long-term survival of the elderly newly administered with parenteral nutrition (PN) or enteral nutrition.

MATERIALS AND METHODS

This multicenter, prospective, observational cohort study was conducted on 546 elderly patients who were administered artificial nutrition. The main outcome was the survival ratio at 180 and 360 days after initiation of 3 different nutrition methods and estimated mean survival time: PN, nasal tube feeding (EN_N), and percutaneous endoscopic gastrostomy (PEG) feeding (EN_G). The incidence of systemic infection was also compared among different cohorts.

RESULTS

At 180 and 360 days after initiation of artificial nutrition, the mortality rates in the PN, EN_N, and EN_G cohorts were 52% and 63%, 32% and 41%, and 22% and 33%, respectively. Multivariate logistic regression analysis showed that, whereas PN nutrition had significant associations with a higher death rate at 180 and 360 days in all samples, there is no significant difference on the main outcome among the 3 cohorts with neurological diseases. A subgroup analysis with neurological diseases showed that the proportional hazard ratios of the PN and EN_N cohorts in comparison with the EN_G cohort were 1.13 (95% confidence interval [CI], 0.66-1.92) and 1.22 (95% CI, 0.82-1.81).

CONCLUSION

There is no significant superiority of PEG feeding compared with nasal tube feeding or PN. Clinicians should consider the choice of nutrition support method, taking into consideration the limitation of the patient's interest.

Combined effects of tauroursodeoxycholic Acid and glutamine on bacterial translocation in obstructive jaundiced rats:

BACKGROUND

Bacterial Translocation is believed to be an important factor on mortality and morbidity in Obstructive Jaundiced.

AIMS

We investigated the probable or estimated positive effects of tauroursodeoxycholic acid, which has antibacterial and regulatory effects on intestinal flora, together with glutamine on BT in an experimental obstructive jaundiced rat model.

STUDY DESIGN

Animal experimentation.

METHODS

Forty adult, male, Sprague Dawley rats were used in this study. Animals were randomised and divided into five groups of eight each: sham (Sh); control (common bile duct ligation, CBDL); and supplementation groups administered tauroursodeoxycholic acid (CBDL+T), glutamine (CBDL+G), or tauroursodeoxycholic acid plus glutamine (CBDL+TG). Blood and liver, spleen, MLN, and ileal samples were taken via laparotomy under sterile conditions for investigation of bacterial translocation and intestinal mucosal integrity and hepatic function tests on the tenth postoperative day.

RESULTS

There were statistically significant differences in BT rates in all samples except the spleen of the CBDL+TG group compared with the CBDL group (p=0.041, p=0.026, and p=0.041, respectively).

CONCLUSION

It is essential to protect hepatic functions besides maintaining intestinal mucosal integrity in the active struggle against BT occurring in obstructive jaundice. The positive effect on intestinal mucosal integrity can be increased if glutamine is used with tauroursodeoxycholic acid, which also has hepatoprotective and immunomodulatory features.

Total parenteral nutrition induces a shift in the Firmicutes to Bacteroidetes ratio in association with Paneth cell activation in rats

The use of total parenteral nutrition (TPN) in the treatment of critically ill patients has been the subject of debate because it has been associated with disturbances in intestinal homeostasis. Important factors in maintaining intestinal homeostasis are the intestinal microbiota and Paneth cells, which exist in a mutually amendable relationship. We hypothesized that the disturbed intestinal homeostasis in TPN-fed individuals results from an interplay between a shift in microbiota composition and alterations in Paneth cells. We studied the microbiota composition and expression of Paneth cell antimicrobial proteins in rats receiving TPN or a control diet for 3, 7, or 14 d. qPCR analysis of DNA extracts from small intestinal luminal contents of TPN-fed rats showed a shift in the Firmicutes:Bacteroidetes ratio in favor of Bacteroidetes after 14 d (P < 0.05) compared with the control group. This finding coincided with greater staining intensity for lysozyme and significantly greater mRNA expression of the Paneth cell antimicrobial proteins lysozyme (P < 0.05), rat α-defensin 5 (P < 0.01), and rat α-defensin 8 (P < 0.01). Finally, 14 d of TPN resulted in greater circulating ileal lipid-binding protein concentrations (P < 0.05) and greater leakage of horseradish peroxidase (P < 0.01), which is indicative of enterocyte damage and a breached intestinal barrier. Our findings show a shift in intestinal microbiota in TPN-fed rats that correlated with changes in Paneth cell lysozyme expression (r(s) = -0.75, P < 0.01). Further studies that include interventions with microbiota or nutrients that modulate them may yield information on the involvement of the microbiota and Paneth cells in TPN-associated intestinal compromise.

Evaluation of a new method for placing nasojejunal feeding tubes

AIM: To compare fluoroscopic, endoscopic and guide wire assistance with ultraslim gastroscopy for placement of nasojejunal feeding tubes.

METHODS: The information regarding nasojejunal tube placement procedures was retrieved using the gastrointestinal tract database at Tongji Hospital affiliated to Tongji Medical College. Records from 81 patients who underwent nasojejunal tubes placement by different techniques between 2004 and 2011 were reviewed for procedure success and tube-related outcomes.

RESULTS: Nasojejunal feeding tubes were successfully placed in 78 (96.3%) of 81 patients. The success rate by fluoroscopy was 92% (23 of 25), by endoscopic technique 96.3% (26 of 27), and by guide wire assistance (whether via transnasal or transoral insertion) 100% (23/23, 6/6). The average time for successful placement was 14.9 ± 2.9 min for fluoroscopic placement, 14.8 ± 4.9 min for endoscopic placement, 11.1 ± 2.2 min for guide wire assistance with transnasal gastroscopic placement, and 14.7 ± 1.2 min for transoral gastroscopic placement. Statistically, the duration for the third method was significantly different (P < 0.05) compared with the other three methods. Transnasal placement over a guidewire was significantly faster (P < 0.05) than any of the other approaches.

CONCLUSION: Guide wire assistance with transnasal insertion of nasojejunal feeding tubes represents a safe, quick and effective method for providing enteral nutrition.

Two-day fasting prior to intestinal ischemia-reperfusion injury on bacterial translocation in rats

PURPOSE

The aim of this study is to verify the effect of two-day fasting prior to intestinal ischemia-reperfusion (I/R) injury on bacterial translocation (BT).

MATERIALS AND METHODS

Mail Sprague-Dawley rats were divided into four groups: group 1, control rats that underwent sham operation only; group 2, rats fasted for two days prior to sham operation; group 3, rats that underwent occlusion of mesenteric vessels for 30 min followed by reperfusion for 4 hr; and group 4, rats fasted for two days prior to the same intestinal I/R injury as in group 3. In all groups, E. coli labeled with (99m)Tc were inoculated into the terminal ileum. Two hr after inoculation of E. coli, the rats were killed. A segment of ileum was obtained for histological examination and samples of mesenteric lymph nodes (MLNs), liver, lung, blood, and spleen were obtained for radioactivity determination.

RESULTS

There were no significant differences in the intestinal mucosa and radioactivity of all samples between groups 1 and 2. Group 3 showed significantly shorter mucosa and villi, and higher radioactivity of samples, except for MLNs, compared to group 1. Group 4 showed similar mucosa and villi, but significantly higher radioactivity of samples, except for MLNs, compared to group 3.

CONCLUSION

Two-day fasting without I/R injury does not cause mucosal change and BT, but in cases following intestinal I/R injury, two-day fasting increases the susceptibility of BT to systemic organs in rats.

Starvation compromises Paneth cells

Lack of enteral feeding, with or without parenteral nutritional support, is associated with increased intestinal permeability and translocation of bacteria. Such translocation is thought to be important in the high morbidity and mortality rates of patients who receive nothing by mouth. Recently, Paneth cells, important constituents of innate intestinal immunity, were found to be crucial in host protection against invasion of both commensal and pathogenic bacteria. This study investigates the influence of food deprivation on Paneth cell function in a mouse starvation model. Quantitative PCR showed significant decreases in mRNA expression of typical Paneth cell antimicrobials, lysozyme, cryptdin, and RegIIIγ, in ileal tissue after 48 hours of food deprivation. Protein expression levels of lysozyme and RegIIIγ precursor were also significantly diminished, as shown by Western blot analysis and IHC. Late degenerative autophagolysosomes and aberrant Paneth cell granules in starved mice were evident by electron microscopy, Western blot analysis, and quantitative PCR. Furthermore, increased bacterial translocation to mesenteric lymph nodes coincided with Paneth cell abnormalities. The current study demonstrates the occurrence of Paneth cell abnormalities during enteral starvation. Such changes may contribute to loss of epithelial barrier function, causing the apparent bacterial translocation in enteral starvation.

Effects of enteral immunonutrition on the maintenance of gut barrier function and immune function in pigs with severe acute pancreatitis

BACKGROUND

This study evaluated the effects of enteral immunonutrition (EIN) supplemented with glutamine, arginine, and probiotics on gut barrier function and immune function in pigs with severe acute pancreatitis (SAP).

METHODS

The model was induced by retrograde injection of 5% sodium taurocholate and trypsin via the pancreatic duct. After induction of SAP, 18 pigs were randomly divided into 3 groups, in which either parenteral nutrition (PN), control enteral nutrition (CEN), or EIN was applied for 8 days. Serum and pancreatic fluid amylase concentration was determined. Intestinal permeability (lactulose to mannitol ratio) was measured by high-performance liquid chromatography, and plasma endotoxin was quantified by the chromogenic limulus amebocyte lysate technique. Samples of venous blood and organs were cultured using standard techniques. Pancreatitis severity and villi of ileum were scored according to histopathologic grading. Plasma T-lymphocyte subsets were measured by flow cytometry, and immunoglobulins (Igs) were determined via enzyme-linked immunosorbent assay.

RESULTS

There were no significant differences in serum and pancreatic fluid amylases concentrations or in pancreatitis severity between any 2 of the 3 groups. Compared with PN and CEN, EIN significantly decreased intestinal permeability, plasma endotoxin concentration, and the incidence and magnitudes of bacterial translocation, but increased ileal mucosal thickness, villous height, crypt depth, and percentage of normal intestinal villi. Significant differences were found in CD3+, CD4+ lymphocyte subsets, the ratio of CD4+: CD8+ lymphocyte subsets, and serum IgA and IgG, but not IgM, between any 2 of the 3 groups.

CONCLUSIONS

EIN maintained gut barrier function and immune function in pigs with SAP.

Effects of intestinal mucosal blood flow and motility on intestinal mucosa

AIM: To investigate the role of intestinal mucosal blood flow (IMBF) and motility in the damage of intestinal mucosal barrier in rats with traumatic brain injury.

METHODS: Sixty-four healthy male Wistar rats were divided randomly into two groups: traumatic brain injury (TBI) group (n = 32), rats with traumatic brain injury; and control group (n = 32), rats with sham-operation. Each group was divided into four subgroups (n = 8) as 6, 12, 24 and 48 h after operation. Intestinal motility was measured by the propulsion ratio of a semi-solid colored marker (carbon-ink). IMBF was measured with the laser-Doppler technique. Endotoxin and D-xylose levels in plasma were measured to evaluate the change of intestinal mucosal barrier function following TBI.

RESULTS: The level of endotoxin was significantly higher in TBI group than in the control group at each time point (0.382 ± 0.014 EU/mL vs 0.102 ± 0.007 EU/mL, 0.466 ± 0.018 EU/mL vs 0.114 ± 0.021 EU/mL, 0.478 ± 0.029 EU/mL vs 0.112 ± 0.018 EU/mL and 0.412 ± 0.036 EU/mL vs 0.108 ± 0.011 EU/mL, P < 0.05). D-xylose concentrations in plasma in TBI group were significantly higher than in the control group (6.68 ± 2.37 mmol/L vs 3.66 ± 1.07 mmol/L, 8.51 ± 2.69 mmol /L vs 3.15 ± 0.95 mmol/L, 11.68 ± 3.24 mmol/L vs 3.78 ± 1.12 mmol/L and 10.23 ± 2.83 mmol/L vs 3.34 ± 1.23 mmol/ L, P < 0.05). The IMBF in TBI group was significantly lower than that in the control group (38.5 ± 2.8 PU vs 45.6 ± 4.6 PU, 25.2 ± 3.1 PU vs 48.2 ± 5.3 PU, 21.5 ± 2.7 PU vs 44.9 ± 2.8 PU, 29. 4 ± 3.8 PU vs 46.7 ± 3.2 PU) (P < 0.05). Significant decelerations of intestinal propulsion ratio in TBI groups were found compared with the control group (0.48% ± 0.06% vs 0.62% ± 0.03%, 0.37% ± 0.05% vs 0.64% ± 0.01%, 0.39% ± 0.07% vs 0.63% ± 0.05% and 0.46% ± 0.03% vs 0.65% ± 0.02%) (P < 0.05).

CONCLUSION: The intestinal mucosal permeability is increased obviously in TBI rats. Decrease of intestinal motility and IMBF occur early in TBI, both are important pathogenic factors for stress-related damage of the intestinal mucosal barrier in TBI.

Glutamine supplementation decreases intestinal permeability and preserves gut mucosa integrity in an experimental mouse model

BACKGROUND

Glutamine (GLN) is the preferred fuel for enterocytes, and GLN supplementation is critical during stressful conditions. The aim of this study was to evaluate the effect of GLN on intestinal barrier permeability and bacterial translocation in a murine experimental model.

METHODS

Swiss male mice (25-30 g) were randomized into 3 groups: (1) sham group; (2) intestinal obstruction (IO) group; (3) IO and GLN (500 mg/kg/d) group. Two different experiments were carried out to assess intestinal permeability and bacterial translocation. In the first experiment, the animals were divided into the 3 groups described above and received diethylenetriamine pentaacetate radiolabeled with technetium ((99m)Tc) on the eighth day. At different time points after intestinal obstruction, blood was collected to determine radioactivity. The animals were killed, and the small intestine was removed for histological analyses. In the bacterial translocation study, on the eighth day all groups received Escherichia coli labeled with (99m)Tc. After 90 minutes, the animals underwent intestinal obstruction and were killed 18 hours later. Blood, mesenteric lymph nodes, liver, spleen, and lungs were removed to determine radioactivity. Statistical significance was considered when P < or = .05.

RESULTS

The levels of intestinal permeability and bacterial translocation were higher in the IO group than in the sham and GLN groups (P < .05). GLN decreased intestinal permeability and bacterial translocation to physiologic levels in the treated animals and preserved intestinal barrier integrity.

CONCLUSIONS

GLN had a positive impact on the intestinal barrier by reducing permeability and bacterial translocation to physiologic levels and preserving mucosal integrity.

Combining enteral with parenteral nutrition to improve postoperative glucose control

The provision of parenteral nutrition (PN) to ‘stressed’ patients often results in hyperglycaemia, which may be detrimental. In animal models limited amounts of enteral nutrition (EN) improve intestinal integrity and stimulate intestinal incretin production, which may lead to improved glucose control. We set out to assess if combining EN with PN results in improved glucose homeostasis rather than PN given alone. We conducted a randomised trial in a university teaching hospital of patients undergoing a ‘curative’ oesophagectomy for adenocarcinoma. Differences between the two intervention groups were assessed for continuous glucose measurement, insulin sensitivity using insulin tolerance tests (ITT) and homeostasis model analysis (HOMA), the incretin glucose-dependent insulinotropic polypeptide (GIP) and intestinal permeability. The combination of PN with EN resulted in lower interstitial glucose concentrations (P = 0·002), reduced insulin resistance, improved insulin sensitivity (HOMA-insulin resistance (IR)P = 0·045; HOMA βP = 0·037; ITTP = 0·006), improved intestinal permeability (P < 0·001) and increased GIP (P = 0·01) when compared with PN alone. The combination of EN with PN, when compared with PN alone, results in reduced glucose concentrations, reduced insulin resistance, increased incretins and improvements in intestinal permeability.

Butyrate enhances the intestinal barrier by facilitating tight junction assembly via activation of AMP-activated protein kinase in Caco-2 cell monolayers

Butyrate, one of the SCFA, promotes the development of the intestinal barrier. However, the molecular mechanisms underlying the butyrate regulation of the intestinal barrier are unknown. To test the hypothesis that the effect of butyrate on the intestinal barrier is mediated by the regulation of the assembly of tight junctions involving the activation of the AMP-activated protein kinase (AMPK), we determined the effect of butyrate on the intestinal barrier by measuring the transepithelial electrical resistance (TER) and inulin permeability in a Caco-2 cell monolayer model. We further used a calcium switch assay to study the assembly of epithelial tight junctions and determined the effect of butyrate on the assembly of epithelial tight junctions and AMPK activity. We demonstrated that the butyrate treatment increased AMPK activity and accelerated the assembly of tight junctions as shown by the reorganization of tight junction proteins, as well as the development of TER. AMPK activity was also upregulated by butyrate during calcium switch-induced tight junction assembly. Compound C, a specific AMPK inhibitor, inhibited the butyrate-induced activation of AMPK. The facilitating effect of butyrate on the increases in TER in standard culture media, as well as after calcium switch, was abolished by compound C. We conclude that butyrate enhances the intestinal barrier by regulating the assembly of tight junctions. This dynamic process is mediated by the activation of AMPK. These results suggest an intriguing link between SCFA and the intracellular energy sensor for the development of the intestinal barrier.

Enterococcus faecalis translocation in mice with severe burn injury: a pathogenic role of CCL2 and alternatively activated macrophages (M2aMphi and M2cMphi)

Here, we investigated a role of CCL2 on the increased susceptibility of severely burned mice to Enterococcus faecalis translocation. After inoculation of Mphi from MLMphi of normal mice, 80% of the SCIDbgMN mice orally infected with the lethal dose of E. faecalis survived, and all mice inoculated with MLMphi from thermally injured mice died. At this time, SCIDbgMN mice inoculated with MLMphi from thermally injured CCL2(-/-) mice were shown to be resistant (90% survival). M1Mphi were not induced by E. faecalis antigen in cultures of MLMphi from thermally injured wild-type mice, and MLMphi from thermally injured CCL2(-/-) mice converted to M1Mphi after the antigen stimulation. MLMphi from wild-type mice 2 days postburn injury possessed M2a- and M2cMphi properties, and those from mice 7-21 days postburn injury carried M2bMphi properties. However, MLMphi from thermally injured CCL2(-/-) mice did not show any typical properties for M2a- or M2cMphi. CCL17 and CXCL13 (biomarkers for M2a- and M2cMphi), but not CCL1 (a biomarker of M2bMphi), were produced by MLMphi from thermally injured CCL2(-/-) mice treated with rCCL2. These results indicate that CCL2 converts resident MLMphi to M2a- and M2cMphi, detected early after burn injury, and decreases host antibacterial innate immunity against sepsis stemming from oral E. faecalis infection.

Enteral and parenteral nutrition distinctively modulate intestinal permeability and T cell function in vitro

BACKGROUND

Nutritional support is an established element of therapy for various indications. However, its impact on the mucosal barrier function is not well understood.

AIM OF THE STUDY

We investigated the influence of EN and PN on intestinal epithelial cells and peripheral blood (PBMC) and lamina propria mononuclear cells (LPMC), all of which are involved in the mucosal defense against bacterial translocation and systemic inflammation.

METHODS

Integrity of epithelial cells was measured as transepithelial electrical resistance (TER) of confluent Caco-2 monolayers in the presence of 1% EN, PN and a parenteral amino acid mixture (AM). To determine wound healing capacities, an established migration model with IEC-6 cells was used. Furthermore, we investigated apoptosis, cell activation, proliferation and cytokine secretion of Caco-2, HT29 and of stimulated PBMC and LPMC cultured with or without 1 and 5% EN, AM or PN.

RESULTS

We demonstrated that EN, AM and PN promoted the integrity of the epithelial monolayer and reconstituted epithelial cell continuity TGF-beta-dependently and -independently. Interestingly, only PN induced apoptosis and decreased the mitochondrial membrane potential. The activation status of PBMC was significantly reduced by EN and AM. Specifically, EN leads to an increased apoptosis rate, inhibited cell cycle progression and increased pro-inflammatory cytokine secretion. Both EN and PN reduced the activation status and the release of pro- and anti-inflammatory cytokines.

CONCLUSIONS

Our study provides evidence that by promoting wound healing and regulating T cell function, EN, AM, and PN potently interact with the intestinal barrier and immune system, thus justifying its use in diseases accompanied by impaired mucosal barrier function.

[The clinical relevance of experimental acute pancreatitis models]

The clinical diagnostics and therapeutic standards applied in the routine management of human acute pancreatitis are based on the results of animal experiments and human studies performed in the past several decades. During this time period, a number of experimental acute pancreatitis models have been developed, which allowed us to study the etiopathogenesis of acute pancreatitis, analyzing the local and remote complications of the inflammatory processes and also the preclinical testing of potentially effective drugs and agents. Only animal models are suitable to examine the very early phase of the pathogenetic processes in acute pancreatitis. In recent years, the progress in molecular genetic methods allowed us to create genetically engineered animal models to clarify the role of different mediators in the pathogenetic process. There is no doubt that the results gained from experimental animal studies are of limited value concerning human pancreatitis. Nevertheless, experimental studies seem to be indispensable in the progress of management of human pancreatic disorders.

Enteral versus parenteral nutrition after gastrointestinal surgery: a systematic review and meta-analysis of randomized controlled trials in the English literature

BACKGROUND

Although previous studies recommend the use of enteral nutrition (EN), the benefit of EN after elective gastrointestinal surgery has not been comprehensively demonstrated as through a meta-analysis. Our aim is to determine whether enteral nutrition is more beneficial than parenteral nutrition.

METHODS

A search was conducted on Medline, Web of Science, the Cochrane Library electronic databases, and bibliographic reviews. The trials were based on randomization, gastrointestinal surgery, and the reporting of at least one of the following end points: any complication, any infectious complication, mortality, wound infection and dehiscence, anastomotic leak, intraabdominal abscess, pneumonia, respiratory failure, urinary tract infection, renal failure, any adverse effect, and duration of hospital stay.

RESULTS

Twenty-nine trials, which included 2,552 patients, met the criteria. EN was beneficial in the reduction of any complication (relative risk (RR), 0.85; 95% confidence interval (CI), 0.74-0.99; P = 0.04), any infectious complication (RR, 0.69; 95% CI, 0.56-0.86; P = 0.001), anastomotic leak (RR, 0.67; 95% CI, 0.47-0.95; P = 0.03), intraabdominal abscess (RR, 0.63; 95% CI, 0.41-0.95; P = 0.03), and duration of hospital stay (weighted mean difference, -0.81; 95% CI, -1.25-0.38; P = 0.02). There were no clear benefits in any of the other complications.

CONCLUSION

The present findings would lead us to recommend the use of EN rather than PN when possible and indicated.

Comparison of effects of total enteral versus total parenteral nutrition on ischemia/reperfusion-induced heart injury in rats

BACKGROUND

The long-term effect of nutrition on cardiac function remains to be elucidated. One possible link is the newly discovered gastric hormone ghrelin, which has been reported to be cardioprotective.

AIM

The present study examined whether total enteral nutrition (TEN) and total parenteral nutrition (TPN) differ in their modulation of ghrelin production and their effects on cardiac function after ischemia/reperfusion injury.

METHODS

Rats received isocaloric parenteral or enteral nutrition through implanted vascular catheters or gastrostomy tubes. TEN was administered in a conventional (TEN-C) or immunonutrition (TEN-I) form. After 7 days, serum ghrelin levels were determined by enzyme-linked immunosorbent assays and myocardial function was assessed using the Langendorff isolated heart technique.

RESULTS

TEN-I animals had significantly higher plasma ghrelin levels than the other groups. After ischemia/reperfusion injury, left ventricular developed pressure decreased in animals receiving TPN when compared to animals receiving TEN-I. Animals receiving TPN also had significant reductions in their maximal rates of increase and decrease in left ventricular pressure when compared to animals receiving TEN-I (unpaired t test, p < 0.05).

CONCLUSION

TEN-I increases serum levels of ghrelin, which protects cardiac function after ischemic/reperfusion injury. Because TEN-I more effectively protects cardiac function, we recommend it for long-term nutritional support.

Total parenteral nutrition causes circumferential intestinal atrophy, remodeling of the intestinal wall, and redistribution of eosinophils in the rat gastrointestinal tract

Total parenteral nutrition (TPN) is held to cause intestinal atrophy and weaken mechanical and immunological barriers. To monitor the degree of atrophy caused by TPN, female Sprague-Dawley rats were, for 8 days, maintained on TPN (n = 6) and compared to identically housed controls given food and water ad libitum (n = 6). Specimens from jejunum, ileum, and colon were taken for histology and morphometric analysis. Topographic distribution and presence of eosinophils, by eosinophil peroxidase (EPO) staining, were examined in the gastric fundus, jejunum, ileum, and colon. Atrophy in terms of a markedly reduced circumference was noted throughout the intestinal tract in all rats subjected to TPN. The width of jejunal and ileal villi was narrowed and the length of jejunal villi was decreased. Furthermore, submucosal thickness in the jejunum and ileum increased. The height of ileal enterocytes remained unaltered. The number of goblet cells decreased in jejunal but not in ileal villi. The Paneth cells, suggested to play important roles in innate defense, increased in size. In the gastric fundus a marked increase in eosinophils was revealed predominantly in the mucosa and submucosa. The number and distribution of jejunal and ileal eosinophils were identical to those of controls. In colon from TPN rats, a redistribution of eosinophils was noted, causing a "band-like" accumulation of eosinophils in the basal portion of the mucosa. In conclusion, TPN causes gut atrophy and an increase in Paneth cell size. Eosinophils increase in number in the gastric fundus and a topographic redistribution occurs in the colon.

Bacterial translocation in rats nonfunctioning diverted distal colon

PURPOSE: To investigate whether the alterations of the diverted colon segment mucosa, evidenced in fecal colitis, would be able to alter Bacterial Translocation (BT). METHODS: Sixty-two Wistar male rats ranging from 220 to 320 grams of weight, were divided in two groups: A (Colostomy) and B (Control), with 31 animals each one. In group A, all animals underwent end colostomy, one stoma, in ascending colon; and in the 70th POD was injected in five rats, by rectal route diverted segment - 2ml of a 0.9% saline solution in animals (A1 subgroup); in eight it was inoculated, by rectal route, 2ml of a solution containing Escherichia coli ATCC 25922 (American Type Culture Collection), in a concentration of 10(8) Colony Forming Unit for milliliters (CFU/ml) - A2 Subgroup; in ten animals the same solution of E. coli was inoculated, in a concentration of 10(11) CFU/ml (A3 Subgroup); and in eight it was collected part of the mucus found in the diverted distal colonic segment for neutral sugars and total proteins dosage (A4 subgroup). The animals from the group B underwent the same procedures of group A, but with differences in the colostomy confection. In rats from subgroups A1, A2, A3, B1, B2, and B3 2ml of blood were aspirated from the heart, and fragments from mesenteric lymphatic nodule, liver, spleen, lung and kidney taken for microbiological analysis, after their death. This analysis consisted of evidencing the presence of E. coli ATCC 25922 CFU. Mann-Whitney and ANOVA Tests were applied as analytic techniques for association of variables. RESULTS: The occurrence of BT was evidenced only in those animals in which inoculated concentration of E. coli ATCC 25922, reached levels of 10(11)CFU/ml, i.e. in Subgroups A3 and B3, although, being significantly greater (80%) in those animals without colostomy (subgroup B3) when compared to the ones with colostomy (20%) from the subgroup A3 (P <0.05). Lung, liver and mesenteric lymphatic nodules were the tissues with larger percentile of bacterial recovery, so much in subgroup A3, as in B3. Blood culture was considered positive in 60% of the animals from subgroup B3 and in 10% of those from subgroup A3 (p <0.05). There was greater concentration of neutral sugars, in subgroup A4 - mean 27.3mg/ml -, than in subgroup B4 - mean 8.4mg/ml - (P <0.05). CONCLUSION: The modifications in the architecture of intestinal mucosa in colitis following fecal diversion can cause alterations in the intestinal barrier, but it does not necessarily lead to an increased frequency of BT.

Effects of granulocyte-colony stimulating factor on peritoneal defense mechanisms and bacterial translocation after administration of systemic chemotherapy in rats

AIM: To investigate the effects of granulocyte-colony stimulating factor (G-CSF) on peritoneal defense mechanisms and bacterial translocation after systemic 5-Fluorouracil (5-FU) administration.

METHODS: Thirty Wistar albino rats were divided into three groups; the control, 5-FU and 5-FU + G-CSF groups. We measured bactericidal activity of the peritoneal fluid, phagocytic activity of polymorphonuclear leucocytes in the peritoneal fluid, total peritoneal cell counts and cell types of peritoneal washing fluid. Bacterial translocation was quantified by mesenteric lymph node, liver and spleen tissue cultures.

RESULTS: Systemic 5-FU reduced total peritoneal cell counts, neutrophils and macrophage numbers. It also altered bactericidal activity of the peritoneal fluid and phagocytic activity of polymorphonuclear leucocytes in the peritoneal fluid. 5-FU also caused significant increase in frequencies of bacterial translocation at the liver and mesenteric lymph nodes. G-CSF decreased bacterial translocation, it significantly enhanced bactericidal activity of the peritoneal fluid and phagocytic activity of polymorphonuclear leucocytes in the peritoneal fluid. It also increased total peritoneal cell counts, neutrophils and macrophage numbers.

CONCLUSION: Systemic 5-FU administration caused bacterial translocation, decreased the bactericidal activity of peritoneal fluid and phagocytic activity of polymorphonuclear leucocytes in the peritoneal fluid. G-CSF increased both bactericidal activity of the peritoneal fluid and phagocytic activity of polymorphonuclear leucocytes in the peritoneal fluid, and prevented the bacterial translocation. We conclude that intraperitoneal GCSF administration protects the effects of systemic 5-FU on peritoneal defense mechanisms.

Bacterial translocation: overview of mechanisms and clinical impact

Bacterial translocation (BT) is a phenomenon in which live bacteria or its products cross the intestinal barrier. Gut translocation of bacteria has been shown in both animal and human studies. BT and its complications have been shown clearly to occur in animal models, but its existence and importance in humans has been difficult to ascertain. We review the mechanisms of BT and its clinical impact based on the current literature.

Optimal nutritional support

There is ongoing debate about the respective roles of enteral and parenteral nutrition. The present short review suggests that these two feeding modalities are not mutually exclusive and that optimal nutritional support may necessitate the concomitant administration of enteral together with parenteral nutrition.

The impact of arginine on bacterial translocation in an intestinal obstruction model in rats

BACKGROUND & AIMS

Arginine has been shown to have multiple beneficial metabolic and immunologic effects in stress situations. Supplementation of arginine has been shown to promote wound healing and intestinal mucosal recovery after trauma, ischemia or intestinal resection. Bacterial translocation has also been evaluated although with conflicting results and using different assessing techniques. Therefore, the aim of this study was to evaluate the effects of arginine on bacterial translocation in an intestinal obstruction model in rats using Escherichia coli labeled with 99mTechnetium.

METHODS

Male Wistar rats (250-350 g) were randomized to receive conventional chow, diet supplemented with pure arginine or diet supplemented with an immunonutrition enteral formula, enriched with arginine, omega-3 fatty acid and RNA. After 7 days, the animals were anesthetized. Terminal ileum was isolated and a ligature was placed around it. E. coli labeled with 99mTechnetium (99mTc-E. coli) was inoculated into the intestinal lumen (terminal ileum). After 24 h, the animals were sacrificed. Blood, mesenteric lymph nodes (MLN), liver, spleen and lungs were removed for radioactivity determination.

RESULTS

Arginine supplementation (300 mg/day, 600 mg/day or present in the enteral formula) reduced the level of bacterial translocation when compared with the control group (p<0.05). This was shown by significantly decrease uptake of 99mTc-E. coli in blood, MLN, liver, spleen and lungs of the animals in the experimental groups (p < 0.05).

CONCLUSIONS

These results have shown that arginine was able to decrease bacteria translocation despite intestinal obstruction. There are several mechanisms which might explain the role of arginine and these will be the subject of future studies.

Associação de glutamina e probióticos no trofismo mucoso do cólon na peritonite experimental

OBJETIVO: O objetivo deste estudo foi investigar o efeito da associação da glutamina e probióticos sobre a mucosa intestinal em ratos submetidos à peritonite experimental. MÉTODO: 16 ratos Wistar (250-350g) com peritonite experimental criada pelo método da punção dupla do ceco foram randomizados para receber diariamente no pós-operatório em conjunto com a dieta, a adição por gavagem de 0,500g de glutamina e leite reconstituído, contendo probióticos (10(6) unidades formadoras de colônias/g de Bifidobacterium lactis BL e Streptococcus thermophilus) (grupo glutamina-probióticos; n=8) ou 0,495g de caseína e leite reconstituído sem probióticos (grupo controle; n=8). O conteúdo das duas dietas foi isonitrogenado e isocalórico. Todos os animais foram sacrificados 120 horas após a peritonite experimental. A profundidade de criptas e espessura de parede da mucosa do cólon foram medidas em biopsias realizadas 2 cm acima da reflexão peritoneal. O restante da mucosa colônica foi pesado e nela mensurou-se o conteúdo de DNA. RESULTADOS: Os animais que receberam glutamina e probióticos apresentaram mucosa mais pesada (0,49±0,12 vs. 0,42±0,07g; p=0,02), maior conteúdo de DNA (0,31±0,07 vs. 0,22±0,05 mg/g de tecido; p<0,01) e criptas mais profundas (272±51 vs. 311±39µ; p=0,04) que o grupo controle. CONCLUSÃO: A associação da glutamina e probióticos confere um maior trofismo na mucosa colônica em ratos submetidos à peritonite experimental.

Total parenteral nutrition-related gastroenterological complications

Total parenteral nutrition is a life saving therapy for patients with chronic gastrointestinal failure, being an effective method for supplying energy and nutrients when oral or enteral feeding is impossible or contraindicated. Clinical epidemiological data indicate that total parenteral nutrition may be associated with a variety of problems. Herein we reviewed data on the gastroenterological tract regarding: (i) total parenteral nutrition-related hepatobiliary complications; and (ii) total parenteral nutrition-related intestinal complications. In the first group, complications may vary from mildly elevated liver enzyme values to steatosis, steatohepatitis, cholestasis, fibrosis and cirrhosis. In particular, total parenteral nutrition is considered to be an absolute risk factor for the development of biliary sludge and gallstones and is often associated with hepatic steatosis and intrahepatic cholestasis. In general, the incidence of total parenteral nutrition-related hepatobiliary complications has been reported to be very high, ranging from 20 to 75% in adults. All these hepatobiliary complications are more likely to occur after long-term total parenteral nutrition, but they seem to be less frequent, and/or less severe in patients who are also receiving oral feeding. In addition, end-stage liver disease has been described in approximately 15-20% of patients receiving prolonged total parenteral nutrition. Total parenteral nutrition-related intestinal complications have not yet been adequately defined and described. Epidemiological studies intended to define the incidence of these complications, are still ongoing. Recent papers confirm that in both animals and humans, total parenteral nutrition-related intestinal complications are induced by the lack of enteral stimulation and are characterised by changes in the structure and function of the gut. Preventive suggestions and therapies for both these gastroenterological complications are reviewed and reported in the present review.

Effects of glutamic acid and taurine on total parenteral nutrition

BACKGROUND

The objective of the present study was to ascertain whether simultaneous administration of glutamic acid (Glu) and taurine (Tau) to patients on total parenteral nutrition (TPN) could improve intestinal mucosal atrophy and suppress bacterial translocation.

METHODS

A 5-day TPN study was conducted in 5-week-old Sprague-Dawley rats. Commercially available Glu was used for TPN in group G and was enhanced with Tau (500 mg kg(-1) day(-1)) in group GT. Oral nutrition was provided in group C controls. At 5 days, amino acid and cytokine levels in plasma and endotoxin levels in portal blood were measured. The histology of the small intestine, liver, and lung were analyzed.

RESULTS

Mucosal thickness and villus height in the small intestine were lower for group G than for groups C and GT. Taurine level in group GT was higher than in group G. Arginine and citrulline levels in groups G and GT were lower than in group C. Taurine level in the small intestine was greater in group GT than in group G. Citrulline concentration was lower in group G than in groups GT and C. Endotoxin level in portal blood and cytokine (tumor necrosis factor alpha, interleukin-1beta, and interleukin-6) levels in blood tended to be lower for group GT than for group G, but no significant differences were noted. Immunostaining showed strong positive reactions to vascular cell adhesion molecule-1 in the liver and lung for group G, and milder reactions for group GT.

CONCLUSIONS

Simultaneous administration of Glu and Tau improved small intestinal mucosal thickness and villus height during TPN. Levels of Tau in the small intestine and plasma increased, and the level of citrulline in the small intestine improved. Decreased expression of adhesion molecules in the liver and lung and improved microcirculation in the liver were also confirmed.