Glutamine Improves Innate Immunity and Prevents Bacterial Enteroinvasion During Parenteral Nutrition

Impact of Glutamine-Enhanced Parenteral Nutrition on Postoperative Outcomes in Colorectal Cancer Patients

Purpose

This study investigated the effects of parenteral glutamine (Gln) supplement immunonutrition versus conventional nutritional support on postoperative Clavien-Dindo classification complications and recovery, perioperative nutritional status, and immune, inflammation, and safety indicators in patients with colorectal cancer (CRC).

Patients and Methods

Clinical data were collected for a retrospective cohort study of 178 patients (58 and 120 patients in the observation and control groups, respectively) who underwent radical resection of CRC from January 2019 to December 2021. The incidence of postoperative complications was calculated. Postoperative recovery, nutritional indicators, inflammatory factors indicator, and the safety indicators before operation and at 1, 3, and 7 days after operation were compared. SPSS 29.0 statistical software was used for statistical analysis.

Results

The incidence of postoperative overall complications in the control group and the observation group was 22.50% (27/120) and 17.24% (10/58), respectively, and there was no significant difference between the two groups (P=0.42). The incidence of postoperative complications of Clavien-Dindo grade ≥III in the control group and the observation group was 14.17% (17/120) and 3.45% (2/58), respectively, and the difference between the two groups was statistically significant (P=0.03). Secondary outcomes (first exhaust, defecation, and liquid diet intake times) were significantly recovered earlier in the observation group than those in the control group (P<0.05), while the postoperative hospital stay was significantly shorter(P=0.04). The perioperative nutritional status did not significantly differ between the groups before and after surgery(P>0.05), although significant differences were observed in several inflammatory and safety indicators(P<0.05).

Conclusion

Unlike conventional nutritional support, postoperative parenteral Gln supplementation reduced the incidence of postoperative Clavien-Dindo complications grade ≥III in patients with CRC while increasing intestinal and immune functions, decreasing inflammation, and reducing the length of hospital stay.

Nutritional Modulation of Host Defense Peptide Synthesis: A Novel Host-Directed Antimicrobial Therapeutic Strategy?

The escalating threat of antimicrobial resistance underscores the imperative for innovative therapeutic strategies. Host defense peptides (HDPs), integral components of innate immunity, exhibit profound antimicrobial and immunomodulatory properties. Various dietary compounds, such as short-chain fatty acids, vitamins, minerals, sugars, amino acids, phytochemicals, bile acids, probiotics, and prebiotics have been identified to enhance the synthesis of endogenous HDPs without provoking inflammatory response or compromising barrier integrity. Additionally, different classes of these compounds synergize in augmenting HDP synthesis and disease resistance. Moreover, dietary supplementation of several HDP-inducing compounds or their combinations have demonstrated robust protection in rodents, rabbits, pigs, cattle, and chickens from experimental infections. However, the efficacy of these compounds in inducing HDP synthesis varies considerably among distinct compounds. Additionally, the regulation of HDP genes occurs in a gene-specific, cell type-specific, and species-specific manner. In this comprehensive review, we systematically summarized the modulation of HDP synthesis and the mechanism of action attributed to each major class of dietary compounds, including their synergistic combinations, across a spectrum of animal species including humans. We argue that the ability to enhance innate immunity and barrier function without triggering inflammation or microbial resistance positions the nutritional modulation of endogenous HDP synthesis as a promising host-directed approach for mitigating infectious diseases and antimicrobial resistance. These HDP-inducing compounds, particularly in combinations, harbor substantial clinical potential for further exploration in antimicrobial therapies for both human and other animals.

New application of intestinal obstruction catheter in enterocutaneous fistula: A case report

BACKGROUND

Enterocutaneous fistula (ECF) is an abnormal connection between the gastrointestinal tract and the skin. ECF can lead to massive body fluid loss, hypercatabolism, and malnutrition. Therefore, nutritional support plays a crucial role in managing ECFs and promoting the healing of fistulas. For nutritional support, enteral nutrition (EN) is the preferred method when gastrointestinal function is recovering. Currently, various EN approaches have been applied for different anatomical positions of the ECF. However, the effectiveness of administering EN support for treating lower ECFs still needs further exploration and improvement.

CASE SUMMARY

We present the case of a 46-year-old male who underwent gastrointestinal stromal tumour resection. Six days after the surgery, the patient presented with fever, fatigue, severe upper abdominal pain, and septic shock. Subsequently, lower ECFs were diagnosed through laboratory and imaging examinations. In addition to symptomatic treatment for homeostasis, total parenteral nutrition support was administered in the first 72 h due to dysfunction of the intestine. After that, we gradually provided EN support through the intestinal obstruction catheter in consideration of the specific anatomic position of the fistula instead of using the nasal jejunal tube. Ultimately, the patient could receive optimal EN support via the catheter, and no complications were found during the treatment.

CONCLUSION

Nutritional support is a crucial element in ECF management, and intestinal obstruction catheters could be used for early EN administration.

Glutamine Ameliorates Liver Steatosis via Regulation of Glycolipid Metabolism and Gut Microbiota in High-Fat Diet-Induced Obese Mice

Obesity and its associated conditions, such as nonalcoholic fatty liver disease (NAFLD), are risk factors for health. The aim of this study was to explore the effects of glutamine (Gln) on liver steatosis induced by a high-fat diet (HFD) and HEPG2 cells induced by oleic acid. Gln demonstrated a positive influence on hepatic homeostasis by suppressing acetyl CoA carboxylase (ACC) and fatty acid synthase (FAS) and promoting sirtuin 1 (SIRT1) expression while improving glucose metabolism by regulating serine/threonine protein kinase (AKT)/factor forkhead box O1 (FOXO1) signals in vivo and in vitro. Obese Gln-fed mice had higher colonic short-chain fatty acid (SCFA) contents and lower inflammation factor protein levels in the liver, HEPG2 cells, and jejunum. Gln-treated obese mice had an effective decrease in Firmicutes abundance. These findings indicate that Gln serves as a nutritional tool in managing obesity and related disorders.

Mechanisms and prevention of intestinal barrier function damage in traumatic hemorrhagic shock

The intestinal barrier is composed of mechanical barrier, chemical barrier, immune barrier, and microbial barrier, which has an important role in defense against microbial invasion. The components of intestinal barrier coordinate with each other under physiological conditions to maintain the homeostasis of intestinal internal and external environment. In traumatic hemorrhagic shock, intestinal barrier function is prone to be impaired by intestinal hypoperfusion, intestinal ischemia-reperfusion injury, and many other factors. Bacterial translocation and endotoxin entry into the blood may occur, leading to enterogenic infection, multiple organ dysfunction, and even death. At present, there are many conceptual updates and technical progress on the mechanisms, prevention, and treatment of intestinal barrier function injury in traumatic hemorrhagic shock both at home and abroad. This paper intends to make a literature review in this field based on the previous research of our team, in order to provide a systematic and comprehensive theoretical system for the clinical prevention and treatment of post-traumatic intestinal dysfunction related diseases.

In-depth investigation of the mechanisms of Echinacea purpurea polysaccharide mitigating alcoholic liver injury in mice via gut microbiota informatics and liver metabolomics

Accumulating evidence suggests that the pathogenesis of alcoholic liver disease (ALD) is strongly correlated with abnormalities of the gut-liver axis. Echinacea purpurea polysaccharide (EPP) is a homogeneous polysaccharide, which has been shown to mitigate ALD. However, the effects of EPP on gut microbiome and consequently on hepatic metabolism have yet to be explored. In this study, the microbiome and metabolomics were combined to explore the effects of EPP on gut microbiota and hepatic metabolism, and the relationship between both was further revealed by Spearman correlation analysis. Results exhibited EPP reversed alcohol-induced disturbances in gut microbiota, evidenced by increased abundance of Muribaculaceae, Lactobacillus, and Bacteroides and decreased abundance of Escherichia_Shigella and Enterococcus. Besides, EPP promoted the production of n-butyric acid, a short-chain fatty acid that maintains the integrity of the intestinal barrier. Moreover, EPP improved alterations in hepatic metabolites, and characteristic metabolites such as Berberine and Ponasterone as well as key metabolic pathways, particularly Nitrogen metabolism, were identified. Furthermore, correlation analysis suggested significant associations between gut microbes and hepatic metabolites, which in turn confirmed EPP alleviated ALD via the gut-liver axis. Therefore, these findings elucidated in-depth mechanisms of EPP against ALD and provided a new target for intervention in alcohol-related diseases.

The Prophylactic Effects of Glutamine on Muscle Protein Synthesis and Degradation in Rats with Ethanol-Induced Liver Damage

The purpose of this research was to investigate the prophylactic effects of glutamine on muscle protein synthesis and degradation in rats with ethanol-induced liver injury. For the first 2 weeks, Wistar rats were divided into two groups and fed a control (n = 16) or glutamine-containing diet (n = 24). For the following 6 weeks, rats fed the control diet were further divided into two groups (n = 8 per group) according to whether their diet contained no ethanol (CC) or did contain ethanol (CE). Rats fed the glutamine-containing diet were also further divided into three groups (n = 8 per group), including a GG group (glutamine-containing diet without ethanol), GE group (control diet with ethanol), and GEG group (glutamine-containing diet with ethanol). After 6 weeks, results showed that hepatic fatty change, inflammation, altered liver function, and hyperammonemia had occurred in the CE group, but these were attenuated in the GE and GEG groups. Elevated intestinal permeability and a higher plasma endotoxin level were observed in the CE group, but both were lower in the GE and GEG groups. The level of a protein synthesis marker (p70S6K) was reduced in the CE group but was higher in both the GE and GEG groups. In conclusion, glutamine supplementation might elevate muscle protein synthesis by improving intestinal health and ameliorating liver damage in rats with chronic ethanol intake.

Influence of Glutamine and Branched-Chain Amino Acids Supplementation during Refeeding in Activity-Based Anorectic Mice

Background: Optimizing the refeeding of patients with anorexia nervosa remains important to limit somatic complications of malnutrition, as well as to avoid disease relapses by targeting persistent mood and intestinal disorders. We aimed to evaluate the effects of glutamine (Gln) and branched-chain amino acids (BCAA) supplementation during refeeding in activity-based anorectic (ABA) mice. Method: Male C57Bl/6 mice were randomized in control and ABA groups. Once ABA-induced malnutrition was established, mice were progressively refed or not. Refed mice had free access to drinking water supplemented or not with 1% Gln or 2.5% BCAA for 10 days. Results: A progressive refeeding was associated with a partial restoration of body weight and lean mass, while a fat mass rebound was observed. In addition, refeeding restored glucose and leptin. Gln did not affect these parameters, while BCAA tended to increase body weight, fat mass, and glycaemia. In the colon, refeeding improved total protein synthesis and restored the LC3II/LC3I ratio, a marker of autophagy. Gln supplementation enhanced colonic protein synthesis, which was associated with an increased p-p70S6kinase/p70S6kinase ratio, whereas these effects were blunted by BCCA supplementation. Conclusions: In ABA mice, Gln and BCAA supplementations during a progressive refeeding fail to restore body weight and lean mass. However, Gln supplementation improves total colonic protein synthesis conversely to BCAA. Further studies are needed to decipher the underlying mechanisms involved in these opposite results.

Nutritional Management of Patients With Enterocutaneous Fistulas: Practice and Progression

The management of enterocutaneous fistulas (ECF) can be challenging because of massive fluid loss, which can lead to electrolyte imbalance, severe dehydration, malnutrition and sepsis. Nutritional support plays a key role in the management and successful closure of ECF. The principle of nutritional support for patients with ECF should be giving enteral nutrition (EN) priority, supplemented by parenteral nutrition if necessary. Although total parenteral nutrition (TPN) may be indicated, use of enteral feeding should be advocated as early as possible if patients are tolerant to it, which can protect gut mucosal barrier and prevent bacterial translocation. A variety of methods of enteral nutrition have been developed such as fistuloclysis and relay perfusion. ECF can also be occluded by special devices and then EN can be implemented, including fibrin glue application, Over-The-Scope Clip placement and three-dimensional (3D)-printed patient-personalized fistula stent implantation. However, those above should not be conducted in acute fistulas, because tissues are edematous and perforation could easily occur.

Glutamine, but not Branched-Chain Amino Acids, Restores Intestinal Barrier Function during Activity-Based Anorexia

Background: During activity-based anorexia (ABA) in mice, enhanced paracellular permeability and reduced protein synthesis have been shown in the colon while the gut–brain axis has received increasing attention in the regulation of intestinal and mood disorders that frequently occur during anorexia nervosa, a severe eating disorder for which there is no specific treatment. In the present study, we assessed the effects of oral glutamine (Gln) or branched-chain amino acids (BCAA) supplementation during ABA to target intestinal functions, body composition and feeding behavior. Methods: C57BL/6 male mice were randomized in Control (CTRL) and ABA groups. After ABA induction, mice received, or not, either 1% Gln or 2.5% BCAA (Leu, Ile, Val) for one week in drinking water. Results: Neither Gln nor BCAA supplementation affected body weight and body composition, while only Gln supplementation slightly increased food intake. ABA mice exhibited increased paracellular permeability and reduced protein synthesis in the colonic mucosa. Oral Gln restored colonic paracellular permeability and protein synthesis and increased the mucin-2 mRNA level, whereas BCAA did not affect colonic parameters. Conclusion: In conclusion, oral Gln specifically improves colonic response during ABA. These data should be further confirmed in AN patients.

Efficacy of parenteral glutamine supplementation in adult hematopoietic stem cell transplantation patients

BACKGROUND

Hematopoietic stem cell transplantation (HSCT) patients need parenteral nutrition because of nausea, vomiting, and mucositis caused by conditioning regimens. The demand for glutamine increases during the HSCT period. We evaluated the effects of glutamine-containing parenteral nutrition on the clinical outcomes of HSCT patients.

METHODS

In this retrospective analysis, we reviewed HSCT patients from Seoul National University from August 2013 to July 2017. Depending on their glutamine supplementation status, 91 patients were divided into 2 groups: glutamine group (N=44) and non-glutamine group (N=47). We analyzed the rate of weight change, infection (clinically/microbiologically documented), complications (duration of mucositis and neutropenia, acute graft versus host disease), and 100-days mortality in each group.

RESULTS

Regarding the clinical characteristics of the patients, there were no significant differences between the 2 groups except that there was a larger proportion of myeloablative conditioning regimen in the glutamine group (P=0.005). In the glutamine group, the average number of days of glutamine use, parenteral nutrition, and mucositis was 7.6±1.4, 14.6±9.9, and 13.3±9.5, respectively. Furthermore, multivariate analysis revealed odds ratios of 0.37 (95% CI, 0.14-0.96; P=0.042) and 0.08 (95% CI, 0.01-0.98; P=0.048) for clinically documented infection and 100-days mortality, respectively, in the glutamine group.

CONCLUSION

Results showed that the glutamine group had less clinically documented infection and 100-days mortality than the non-glutamine group, but the other outcomes did not show significant differences. The extended duration of glutamine supplementation according to the period of total parenteral nutrition and mucositis should be considered.

[Clinical effect of alanyl-glutamine-enriched nutritional support in the treatment of children with abdominal Henoch-Schönlein purpura]

OBJECTIVE

To study the clinical effect of alanyl-glutamine-enriched nutritional support in the treatment of children with abdominal Henoch-Schönlein purpura.

METHODS

Children with abdominal Henoch-Schönlein purpura who needed nutritional support were enrolled and stratified according to age, sex and the severity of disease, and were randomly divided into a control group (n=118) and an enriched nutritional support group (n=107). The control group was given nutritional support without using alanyl-glutamine, while the enriched nutritional support group was given alanyl-glutamine-enriched nutritional support. Intravenous steroids were used according to the severity of disease in both groups. Other therapies were the same in the two groups. The two groups were compared in terms of the length of hospital stay, the rate and duration of use of intravenous steroids, the recurrence rate of symptoms during hospitalization, the rate of total parenteral nutrition (TPN), the rate of weight loss and the rate of fasting for more than 5 days. All patients were followed up for 3 months after discharge to monitor the recurrence of symptoms.

RESULTS

There were no significant differences in the length of hospital stay, the rate of TPN and the rate of fasting for more than 5 days between the two groups (P>0.05). Compared with the enriched nutritional support group, the control group showed significant increases in the rate and duration of use of intravenous steroids, the recurrence rate of symptoms and the rate of weight loss (P<0.05). After the 3-month follow-up, all the children resumed normal diet, and the recurrence rate of digestive symptoms was less than 20% in each group. Abdominal pain was the most common symptom (83.33%, 30/36), followed by vomiting and abdominal distention. No digestive hemorrhage was observed. All the symptoms were relieved after symptomatic treatment. No significant difference was found between the two groups in the recurrence rate of digestive symptoms (P=0.693).

CONCLUSIONS

Alanyl-glutamine-enriched nutritional support in the treatment of children with abdominal Henoch-Schönlein purpura can reduce the use of intravenous steroids and weight loss, but without impact on the length of hospital stay and post-discharge recurrence.

[Clinical effect of alanyl-glutamine-enriched nutritional support in the treatment of children with abdominal Henoch-Schönlein purpura]

OBJECTIVE

To study the clinical effect of alanyl-glutamine-enriched nutritional support in the treatment of children with abdominal Henoch-Schönlein purpura.

METHODS

Children with abdominal Henoch-Schönlein purpura who needed nutritional support were enrolled and stratified according to age, sex and the severity of disease, and were randomly divided into a control group (n=118) and an enriched nutritional support group (n=107). The control group was given nutritional support without using alanyl-glutamine, while the enriched nutritional support group was given alanyl-glutamine-enriched nutritional support. Intravenous steroids were used according to the severity of disease in both groups. Other therapies were the same in the two groups. The two groups were compared in terms of the length of hospital stay, the rate and duration of use of intravenous steroids, the recurrence rate of symptoms during hospitalization, the rate of total parenteral nutrition (TPN), the rate of weight loss and the rate of fasting for more than 5 days. All patients were followed up for 3 months after discharge to monitor the recurrence of symptoms.

RESULTS

There were no significant differences in the length of hospital stay, the rate of TPN and the rate of fasting for more than 5 days between the two groups (P>0.05). Compared with the enriched nutritional support group, the control group showed significant increases in the rate and duration of use of intravenous steroids, the recurrence rate of symptoms and the rate of weight loss (P<0.05). After the 3-month follow-up, all the children resumed normal diet, and the recurrence rate of digestive symptoms was less than 20% in each group. Abdominal pain was the most common symptom (83.33%, 30/36), followed by vomiting and abdominal distention. No digestive hemorrhage was observed. All the symptoms were relieved after symptomatic treatment. No significant difference was found between the two groups in the recurrence rate of digestive symptoms (P=0.693).

CONCLUSIONS

Alanyl-glutamine-enriched nutritional support in the treatment of children with abdominal Henoch-Schönlein purpura can reduce the use of intravenous steroids and weight loss, but without impact on the length of hospital stay and post-discharge recurrence.

The gut in trauma

PURPOSE OF REVIEW

The purpose of this review is to describe established and emerging mechanisms of gut injury and dysfunction in trauma, describe emerging strategies to improve gut dysfunction, detail the effect of trauma on the gut microbiome, and describe the gut-brain connection in traumatic brain injury.

RECENT FINDINGS

Newer data suggest intraluminal contents, pancreatic enzymes, and hepatobiliary factors disrupt the intestinal mucosal layer. These mechanisms serve to perpetuate the inflammatory response leading to multiple organ dysfunction syndrome (MODS). To date, therapies to mitigate acute gut dysfunction have included enteral nutrition and immunonutrition; emerging therapies aimed to intestinal mucosal layer disruption, however, include protease inhibitors such as tranexamic acid, parenteral nutrition-supplemented bombesin, and hypothermia. Clinical trials to demonstrate benefit in humans are needed before widespread applications can be recommended.

SUMMARY

Despite resuscitation, gut dysfunction promotes distant organ injury. In addition, postresuscitation nosocomial and iatrogenic 'hits' exaggerate the immune response, contributing to MODS. This was a provocative concept, suggesting infectious and noninfectious causes of inflammation may trigger, heighten, and perpetuate an inflammatory response culminating in MODS and death. Emerging evidence suggests posttraumatic injury mechanisms, such as intestinal mucosal disruption and shifting of the gut microbiome to a pathobiome. In addition, traumatic brain injury activates the gut-brain axis and increases intestinal permeability.

Effect of parenteral glutamine supplementation combined with enteral nutrition on Hsp90 expression and Peyer's patch apoptosis in severely burned rats

OBJECTIVES

The aim of this study was to investigate the effects of parenteral glutamine (GLN) supplementation combined with enteral nutrition (EN) on heat shock protein (Hsp) 90 expression and Peyer's patch (PP) apoptosis in severely burned rats.

METHODS

Male Sprague-Dawley (SD) rats were randomly assigned to four groups: Sham burn + EN + GLN-free amino acid (AA; n = 10), sham burn + EN + GLN (n = 10), burn + EN + AA (n = 10), and burn + EN + GLN (n = 10). Two hours after a 30% total body surface area (TBSA), full-thickness scald burn injury on the back, burned rats in two of the experimental groups (burn + EN + AA and burn + EN + GLN groups) were fed with a conventional EN solution by oral gavage for 7 d. Simultaneously, rats in the burn + EN + GLN group were given 0.35 g GLN/kg body weight/d once via a tail vein injection for 7 d and rats in the burn + EN + AA group were administered isocaloric/isonitrogenous GLN-free amino acid solution (Tyrosine) for comparison. Rats in two sham burn control groups (sham burn + EN + AA and sham burn + EN + GLN groups) were treated in the same manner except for the burn injury. All rats in the four groups were given 175 kcal/kg body wt/d. There was isonitrogenous, isovolumic, and isocaloric intake among the four groups. At the end of the seventh day after completion of the nutritional program, all rats were anesthetized and samples were collected for further analysis. PP apoptosis was measured by terminal deoxyuridine nick-end labeling (TUNEL). The expression of Hsp90 in PPs was analyzed by western blotting. Caspase-3 activity of PPs was also assessed. Levels of proinflammatory cytokines of gut tissues were evaluated by enzyme-linked immunosorbent assay (ELISA). The intestinal immunoglobulin A (IgA) content was also determined by ELISA.

RESULTS

The results revealed that intestinal IgA content in rats of the burn + EN + GLN group were significantly increased compared with those in the burn + EN + AA group (P < 0.05). The expression of Hsp90 of PPs in rats in the burn + EN + GLN group was significantly upregulated compared with those in the burn + EN + AA group (P < 0.05). On the other hand, levels of proinflammatory cytokines of gut tissues, caspase-3 activity, and the number of TUNEL-stained cells of PPs in rats of the burn + EN + GLN group were markedly decreased compared with those of the burn + EN + AA group (P < 0.05).

CONCLUSIONS

The results of this study show that parenteral glutamine supplementation combined with EN may upregulate the expression of Hsp90, reduce caspase-3 activity, lessen the release of proinflammatory cytokines, attenuate PP apoptosis, and improve intestinal IgA response in burned rats. Clinically, therapeutic efforts to improve intestinal immunity may contribute to a favorable outcome in severely burned patients.

N-3 polyunsaturated fatty acid-enriched lipid emulsion improves Paneth cell function via the IL-22/Stat3 pathway in a mouse model of total parenteral nutrition

Total parenteral nutrition (TPN) is a life-saving therapy for patients with gastrointestinal dysfunction or failure. Long-term TPN impairs gut barrier function and contributes to infections and poor clinical outcomes. However, the underlying mechanisms of TPN-related gut barrier damage have not been fully elucidated, and effective measures are still rare. Here, we compared the effects of a predominantly n-6 polyunsaturated fatty acids emulsion (PUFAs; Intralipid) and a lipid emulsion containing n-3 PUFAs (Intralipid plus Omegaven) on antimicrobial peptides produced by Paneth cells. Our results show for the first time that n-3 PUFAs markedly ameliorated intestine atrophy, and increased protein levels of lysozyme, RegIIIγ, and α-cryptdin 5, and their mRNA expression, compared to the n-6 PUFAs emulsion. Importantly, our study reveals that downregulation of IL-22 and phosphorylated Stat3 (p-Stat3) is associated with Paneth cell dysfunction, which may mediate TPN-related gut barrier damage. Lastly, n-3 PUFAs upregulated levels of IL-22 and increased the p-Stat3/Stat3 ratio in ileal tissue, suggesting that n-3 PUFAs improve Paneth cell function through activation of the IL-22/Stat3 pathway. Therefore, our study provides a cogent explanation for the beneficial effects of n-3 PUFAs, and indicates the IL-22/Stat3 pathway as a promising target in the treatment of TPN-related gut barrier damage.

Effects of n-3 PUFAs on Intestinal Mucosa Innate Immunity and Intestinal Microbiota in Mice after Hemorrhagic Shock Resuscitation

n-3 polyunsaturated fatty acids (PUFAs) can improve the function of the intestinal barrier after damage from ischemia-reperfusion or hemorrhagic shock resuscitation (HSR). However, the effects of n-3 PUFAs on intestinal microbiota and the innate immunity of the intestinal mucosa after HSR remain unclear. In the present study, 40 C57BL/6J mice were randomly assigned to five groups: control, sham, HSR, HSR + n-3 PUFAs and HSR + n-6 PUFAs. Mice were sacrificed 12 h after HSR. Liver, spleen, mesenteric lymph nodes and terminal ileal tissues were collected. Intestinal mucosae were scraped aseptically. Compared with the HSR group, the number of goblet cells increased, expression of mucin 2 was restored and disturbed intestinal microbiota were partly stabilized in the PUFA-administered groups, indicating that both n-3 and n-6 PUFAs reduced overproliferation of Gammaproteobacteria while promoting the growth of Bacteroidetes. Notably, n-3 PUFAs had an advantage over n-6 PUFAs in improving ileal tissue levels of lysozyme after HSR. Thus, PUFAs, especially n-3 PUFAs, partly improved the innate immunity of intestinal mucosa in mice after HSR. These findings suggest a clinical rationale for providing n-3 PUFAs to patients recovering from ischemia-reperfusion.

Effect of parenteral glutamine supplementation combined with enteral nutrition on Hsp90 expression and lymphoid organ apoptosis in severely burned rats

OBJECTIVE

The aim of this study is to investigate the effects of parenteral glutamine(GLN) supplementation combined with enteral nutrition (EN) on heat shock protein 90(Hsp90) expression, apoptosis of lymphoid organs and circulating lymphocytes, immunological function and survival in severely burned rats.

METHODS

Male SD rats were randomly assigned into 4 groups: a sham burn+EN+GLN-free amino acid (AA) group (n=10), a sham burn+EN+GLN group (n=10), a burn+EN+AA group (n=10), and a burn +EN +GLN group (n=10). Two hours after a 30% total body surface area (TBSA), full-thickness scald burn injury on the back was made, the burned rats in two experimental groups (the burn+EN+AA group and the burn+EN +GLN group) were fed with a conventional enteral nutrition solution by oral gavage for 7 days. Simultaneously, the rats in the burn+EN+GLN group were given 0.35g GLN/kg body weight/day once via a tail vein injection for 7 days, whereas those in the burn+EN+AA group were administered isocaloric/isonitrogenous GLN-free amino acid solution (Tyrosine) for comparison. The rats in two sham burn control groups (the sham burn+EN+AA group and the sham burn+EN +GLN group) were treated in the same procedure as above, except for burn injury. All rats in each of the four groups were given 175kcal/kg body wt/day. There was isonitrogenous, isovolumic and isocaloric intake among four groups. At the end of the 7th day after nutritional programme were finished, all rats were anesthetized and samples were collected for further analysis. Serum immunoglobulin quantification was conducted by ELISA. Circulating lymphocyte numbers were counted by Coulter LH-750 Analyzer. The percentages and apoptotic ratio of CD4 and CD8T lymphocytes in circulation were determined by flow cytometry (FCM). The neutrophil phagocytosis index (NPI) was examined. The GLN concentrations in plasma, thymus, spleen and skeletal muscle were measured by high performance liquid chromatography (HPLC). The organ index evaluation and TUNEL analysis of thymus and spleen were carried out. The expression of Hsp90 in thymus and spleen was analyzed by western blotting. Moreover, the survival in burned rats was observed.

RESULTS

The results revealed that parenteral GLN supplementation combined with EN significantly increased the GLN concentrations of plasma and tissues, the serum immunoglobulin content, the circulating lymphocyte number, the CD4/CD8 ratio, the indexes of thymus and spleen, NPI and survival as compared with the burn+EN+AA group (p<0.05). The expression of Hsp90 in thymus and spleen in the burn+EN+GLN group was significantly up-regulated as compared with the burn+EN+AA group (p<0.05). The apoptosis in circulating CD4 and CD8 lymphocytes, thymus and spleen in the burn+EN+GLN group was significantly decreased as compared with the burn+EN+AA group (p<0.05).

CONCLUSION

The results of this study show that parenteral GLN supplementation combined with EN may increase the GLN concentrations of plasma and tissues, up-regulate the expression of Hsp90, attenuate apoptosis in lymphoid organ and circulating lymphocyte, enhance the immunological function and improve survival in severely burned rats. Clinically, therapeutic efforts at the modulation of the immune dysfunction may contribute to a favorable outcome in severely burned patients.

Efficacy and Safety of Glutamine-supplemented Parenteral Nutrition in Surgical ICU Patients: An American Multicenter Randomized Controlled Trial

OBJECTIVE

To determine whether glutamine (GLN)-supplemented parenteral nutrition (PN) improves clinical outcomes in surgical intensive care unit (SICU) patients.

SUMMARY BACKGROUND DATA

GLN requirements may increase with critical illness. GLN-supplemented PN may improve clinical outcomes in SICU patients.

METHODS

A parallel-group, multicenter, double-blind, randomized, controlled clinical trial in 150 adults after gastrointestinal, vascular, or cardiac surgery requiring PN and SICU care. Patients were without significant renal or hepatic failure or shock at entry. All received isonitrogenous, isocaloric PN [1.5 g/kg/d amino acids (AAs) and energy at 1.3× estimated basal energy expenditure]. Controls (n = 75) received standard GLN-free PN (STD-PN); the GLN group (n = 75) received PN containing alanyl-GLN dipeptide (0.5 g/kg/d), proportionally replacing AA in PN (GLN-PN). Enteral nutrition (EN) was advanced and PN weaned as indicated. Hospital mortality and infections were primary endpoints.

RESULTS

Baseline characteristics, days on study PN and daily macronutrient intakes via PN and EN, were similar between groups. There were 11 hospital deaths (14.7%) in the GLN-PN group and 13 deaths in the STD-PN group (17.3%; difference, -2.6%; 95% confidence interval, -14.6% to 9.3%; P = 0.66). The 6-month cumulative mortality was 31.4% in the GLN-PN group and 29.7% in the STD-PN group (P = 0.88). Incident bloodstream infection rate was 9.6 and 8.4 per 1000 hospital days in the GLN-PN and STD-PN groups, respectively (P = 0.73). Other clinical outcomes and adverse events were similar.

CONCLUSIONS

PN supplemented with GLN dipeptide was safe, but did not alter clinical outcomes among SICU patients.

Partial Enteral Nutrition Preserves Elements of Gut Barrier Function, Including Innate Immunity, Intestinal Alkaline Phosphatase (IAP) Level, and Intestinal Microbiota in Mice

Lack of enteral nutrition (EN) during parenteral nutrition (PN) leads to higher incidence of infection because of gut barrier dysfunction. However, the effects of partial EN on intestina linnate immunity, intestinal alkaline phosphatase (IAP) and microbiota remain unclear. The mice were randomized into six groups to receive either standard chow or isocaloric and isonitrogenous nutritional support with variable partial EN to PN ratios. Five days later, the mice were sacrificed and tissue samples were collected. Bacterial translocation, the levels of lysozyme, mucin 2 (MUC2), and IAP were analyzed. The composition of intestinal microbiota was analyzed by 16S rRNA pyrosequencing. Compared with chow, total parenteral nutrition (TPN) resulted in a dysfunctional mucosal barrier, as evidenced by increased bacterial translocation (p < 0.05), loss of lysozyme, MUC2, and IAP, and changes in the gut microbiota (p < 0.001). Administration of 20% EN supplemented with PN significantly increased the concentrations of lysozyme, MUC2, IAP, and the mRNA levels of lysozyme and MUC2 (p < 0.001). The percentages of Bacteroidetes and Tenericutes were significantly lower in the 20% EN group than in the TPN group (p < 0.001). These changes were accompanied by maintained barrier function in bacterial culture (p < 0.05). Supplementation of PN with 20% EN preserves gut barrier function, by way of maintaining innate immunity, IAP and intestinal microbiota.

Bombesin Preserves Goblet Cell Resistin-Like Molecule β During Parenteral Nutrition but Not Other Goblet Cell Products

INTRODUCTION

Parenteral nutrition (PN) increases the risk of infection in critically ill patients and is associated with defects in gastrointestinal innate immunity. Goblet cells produce mucosal defense compounds, including mucin (principally MUC2), trefoil factor 3 (TFF3), and resistin-like molecule β (RELMβ). Bombesin (BBS), a gastrin-releasing peptide analogue, experimentally reverses PN-induced defects in Paneth cell innate immunity. We hypothesized that PN reduces goblet cell product expression and PN+BBS would reverse these PN-induced defects.

METHODS

Two days after intravenous cannulation, male Institute of Cancer Research mice were randomized to chow (n = 15), PN (n = 13), or PN+BBS (15 µg tid) (n = 12) diets for 5 days. Defined segments of ileum and luminal fluid were analyzed for MUC2, TFF3, and RELMβ by quantitative reverse transcriptase polymerase chain reaction and Western blot. Th2 cytokines interleukin (IL)-4 and IL-13 were measured by enzyme-linked immunosorbent assay.

RESULTS

Compared with chow, PN significantly reduced MUC2 in ileum (P < .01) and luminal fluid (P = .01). BBS supplementation did not improve ileal or luminal MUC2 compared with PN (P > .3). Compared with chow, PN significantly reduced TFF3 in ileum (P < .02) and luminal fluid (P < .01). BBS addition did not improve ileal or luminal TFF3 compared with PN (P > .3). Compared with chow, PN significantly reduced ileal RELMβ (P < .01). BBS supplementation significantly increased ileal RELMβ to levels similar to chow (P < .03 vs PN; P > .6 vs chow). Th2 cytokines were decreased with PN and returned to chow levels with BBS.

CONCLUSION

PN significantly impairs the goblet cell component of innate mucosal immunity. BBS only preserves goblet cell RELMβ during PN but not other goblet cell products measured.