Glutamine metabolism by the intestinal tract

Wheat peptides inhibit the activation of MAPK and NF-κB inflammatory pathways and maintain epithelial barrier integrity in NSAID-induced intestinal epithelial injury

The use of non-steroidal anti-inflammatory drugs (NSAIDs) has negative effects on the gastrointestinal tract, but the proton pump inhibitors currently in use only protect against gastrointestinal disease and may even make NSAID-induced enteropathy worse. Therefore, new approaches to treating enteropathy are required. This study aimed to investigate the protective effect of wheat peptides (WPs) against NSAID-induced intestinal damage in mice and their mechanism. Here, an in vivo mouse model was built to investigate the protective and reparative effects of different concentrations of WPs on NSAID-induced intestinal injury. WPs ameliorated NSAID-induced weight loss and small intestinal tissue damage in mice. WP treatment inhibited NSAID-induced injury leading to increased levels of oxidative stress and expression levels of inflammatory factors. WPs protected and repaired the integrity and permeability injury of the intestinal tight junction induced by NSAIDs. An in vitro Caco-2 cell model was built with lipopolysaccharide (LPS). WP pretreatment inhibited LPS-induced changes in the Caco-2 cell permeability and elevated the levels of oxidative stress. WPs inhibited LPS-induced phosphorylation of NF-κB p65 and mitogen-activated protein kinase (MAPK) signaling pathways and reduced the expression of inflammatory factors. In addition, WPs increased tight junction protein expression, which contributed to improved intestinal epithelial dysfunction. Our results suggest that WPs can ameliorate NSAID-induced impairment of intestinal barrier functional integrity by improving intestinal oxidative stress levels and reducing inflammatory factor expression through inhibition of NF-κB p65 and MAPK signaling pathway activation. WPs can therefore be used as potential dietary supplements to reduce NSAID-induced injury of the intestine.

Perioperative cognition in association with malnutrition and frailty: a narrative review

Postoperative delirium (POD) is a prevalent clinical entity characterized by reversible fluctuating altered mental status and cognitive impairment with acute and rapid onset a few days after major surgery. Postoperative cognitive decline (POCD) is a more permanent extension of POD characterized by prolonged global cognitive impairment for several months to years after surgery and anesthesia. Both syndromes have been shown to increase morbidity and mortality in postoperative patients making their multiple risk factors targets for optimization. In particular, nutrition imparts a significant and potentially reversible risk factor. Malnutrition and frailty have been linked as risk factors and predictive indicators for POD and less so for POCD. This review aims to outline the association between nutrition and perioperative cognitive outcomes as well as potential interventions such as prehabilitation.

Endogenous glutamine is rate-limiting for anti-CD3 and anti-CD28 induced CD4+ T-cell proliferation and glycolytic activity under hypoxia and normoxia

To meet the demand for energy and biomass, T lymphocytes (T cells) activated to proliferation and clonal expansion, require uptake and metabolism of glucose (Gluc) and the amino acid (AA) glutamine (Gln). Whereas exogenous Gln is converted to glutamate (Glu) by glutaminase (GLS), Gln is also synthesized from the endogenous pool of AA through Glu and activity of glutamine synthase (GS). Most of this knowledge comes from studies on cell cultures under ambient oxygen conditions (normoxia, 21% O2). However, in vivo, antigen induced T-cell activation often occurs under moderately hypoxic (1-4% O2) conditions and at various levels of exogenous nutrients. Here, CD4+ T cells were stimulated for 72 h with antibodies targeting the CD3 and CD28 markers at normoxia and hypoxia (1% O2). This was done in the presence and absence of the GLS and GS inhibitors, Bis-2-(5-phenylacetamido-1,3,4-thiadiazol-2-yl) ethyl sulfide (BPTES) and methionine sulfoximine (MSO) and at various combinations of exogenous Gluc, Gln and pyruvate (Pyr) for the last 12 h of stimulation. We found that T-cell proliferation, viability and levels of endogenous AA were significantly influenced by the availability of exogenous Gln, Gluc and Pyr as well as inhibition of GLS and GS. Moreover, inhibition of GLS and GS and levels of oxygen differentially influenced oxygen consumption rate (OCR) and extracellular acidification rate (ECAR). Finally, BPTES-dependent down-regulation of ECAR was associated with reduced hexokinase (HK) activity at both normoxia and hypoxia. Our results demonstrate that Gln availability and metabolism is rate-limiting for CD4+ T-cell activity.

Preventive and Regenerative Effect of Glutamine and Probiotics on Gastric Mucosa in an Experimental Model of Alcohol-Induced Injury in Male Holtzman Rats

Background: The purpose of this study was to measure the preventive and regenerative effect of glutamine and probiotics induced by alcohol injury in Holtzman rats. Methods: Analytical, experimental and prospective study. The population consisted of 56 male rats between 300 and 350 g, distributed in three experimental phases: Pre-pilot phase PPP (6 rats), Pilot phase PP (10 rats), and Experimental phase EP (40 rats). In the pilot phase, 10 rats were subjected to damage with 8.5% ethanol, which was given intragastrically. The dosage was calculated for 10 rats in two groups: the first with 7.5 mL/kg in 5 rats and the second with 8.5 mL/kg in 5 rats. The experimental phase was performed in 40 rats divided into 6 groups, the negative control group (healthy), positive control group (injured), preventive experimental group (glutamine and glutamine with probiotic) and regenerative experimental group (glutamine and glutamine with probiotic). At the end of each phase, the rats were sacrificed with sodium pentobarbital (Halathal) and a portion of their stomachs was stored in formol. Results: The evaluation of stomach tissue samples (desquamation, erythema, hyperemia) showed that in the preventive phase, glutamine shows effectiveness in comparison to glutamine with probiotic. In the regenerative phase, glutamine and glutamine with probiotic did not show significant differences. Conclusions: Glutamine and probiotics can potentially serve as a therapy for the treatment for gastritis.

Alpha-Ketoglutarate dietary supplementation to improve health in humans

Alpha-ketoglutarate (AKG) is an intermediate in the Krebs cycle involved in various metabolic and cellular pathways. As an antioxidant, AKG interferes in nitrogen and ammonia balance, and affects epigenetic and immune regulation. These pleiotropic functions of AKG suggest it may also extend human healthspan. Recent studies in worms and mice support this concept. A few studies published in the 1980s and 1990s in humans suggested the potential benefits of AKG in muscle growth, wound healing, and in promoting faster recovery after surgery. So far there are no recently published studies demonstrating the role of AKG in treating aging and age-related diseases; hence, further clinical studies are required to better understand the role of AKG in humans. This review will discuss the regulatory role of AKG in aging, as well as its potential therapeutic use in humans to treat age-related diseases.

Strategies to Mitigate Chemotherapy and Radiation Toxicities That Affect Eating

Background: Cancer and its therapy is commonly associated with a variety of side effects that impact eating behaviors that reduce nutritional intake. This review will outline potential causes of chemotherapy and radiation damage as well as approaches for the amelioration of the side effects of cancer during therapy. Methods: Information for clinicians, patients, and their caregivers about toxicity mitigation including nausea reduction, damage to epithelial structures such as skin and mucosa, organ toxicity, and education is reviewed. Results: How to anticipate, reduce, and prevent some toxicities encountered during chemotherapy and radiation is detailed with the goal to improve eating behaviors. Strategies for health care professionals, caregivers, and patients to consider include (a) the reduction in nausea and vomiting, (b) decreasing damage to the mucosa, (c) avoiding a catabolic state and muscle wasting (sarcopenia), and (d) developing therapeutic alliances with patients, caregivers, and oncologists. Conclusions: Although the reduction of side effects involves anticipatory guidance and proactive team effort (e.g., forward observation, electronic interactions, patient reported outcomes), toxicity reduction can be satisfying for not only the patient, but everyone involved in cancer care.

Re-examining chemically defined liquid diets through the lens of the microbiome

Trends in nutritional science are rapidly shifting as information regarding the value of eating unprocessed foods and its salutary effect on the human microbiome emerge. Unravelling the evolution and ecology by which humans have harboured a microbiome that participates in every facet of health and disease is daunting. Most strikingly, the host habitat has sought out naturally occurring foodstuff that can fulfil its own metabolic needs and also the needs of its microbiota, each of which remain inexorably connected to one another. With the introduction of modern medicine and complexities of critical care, came the assumption that the best way to feed a critically ill patient is by delivering fibre-free chemically defined sterile liquid foods (that is, total enteral nutrition). In this Perspective, we uncover the potential flaws in this assumption and discuss how emerging technology in microbiome sciences might inform the best method of feeding malnourished and critically ill patients.

Replacing dietary antibiotics with 0.20% l-glutamine in swine nursery diets: impact on intestinal physiology and the microbiome following weaning and transport

Previous research demonstrates that supplementing 0.20% l-glutamine (GLN) in the diets of newly weaned and transported pigs improves growth rate to a similar extent as providing dietary antibiotics (AB). However, research comparing the effects of GLN vs. AB on intestinal physiology and the microbiome is limited. Therefore, the study objective was to compare the effects of supplementing nursery diets with GLN, AB, or no dietary antibiotics (NA) on intestinal physiology and the microbiome of pigs in a production environment following weaning and transport. Mixed-sex piglets (N = 480; 5.62 ± 0.06 kg body weight [BW]) were weaned (18.4 ± 0.2 d of age) and transported for 12 h in central Indiana, for two replicates, during the summer of 2016 and the spring of 2017. Pens were blocked by BW and allotted to one of the three dietary treatments (n = 10 pens/dietary treatment/replicate [8 pigs/pen]): AB (chlortetracycline [441 ppm] + tiamulin [38.6 ppm]), GLN (0.20% as-fed), or NA fed for 14 d. From day 14 to 34, pigs were fed common AB-free diets in two phases. On day 33, villus height:crypt depth tended to be increased (P = 0.07; 7.0%) in GLN and AB pigs vs. NA pigs. On day 33, glucagon-like peptide 2 (GLP-2) mRNA abundance was decreased (P = 0.01; 50.3%) in GLN and NA pigs vs. AB pigs. Crypt depth was increased overall on day 33 (P = 0.01; 16.2%) during the spring replicate compared with the summer replicate. Villus height:crypt depth was reduced (P = 0.01; 9.6%) during the spring replicate compared with the summer replicate on day 33. On day 13, tumor necrosis factor-alpha and occludin mRNA abundance was increased (P ≤ 0.04; 45.9% and 106.5%, respectively) and zonula occludens-1 mRNA abundance tended to be greater (P = 0.10; 19.2%) in the spring replicate compared with the summer replicate. In addition, AB pigs had increased (P = 0.01; 101.3%) GLP-2 mRNA abundance compared with GLN and NA pigs. Microbiome analysis indicated that on day 13, dietary treatment altered the microbiota community structure (P = 0.03). Specifically, the AB pigs tended to be distinct from both the NA and GLN pigs (P = 0.08), and Lactobacillus was increased nearly 2-fold in AB compared with NA pigs (q = 0.04) and GLN pigs (q = 0.22). In conclusion, GLN supplementation tended to improve some morphological markers of intestinal health similarly to AB pigs, while the microbiome composition in GLN pigs was more similar to NA pigs than AB pigs.

Myosin light chain kinase mediates intestinal barrier dysfunction following simulated microgravity based on proteomic strategy

Microgravity induces injury of intestinal barrier. However, the underlying mechanism remains unclear. The present study aimed to investigate the pathological change of intestinal mucosa induced by long term simulated microgravity and to explore its etiological mechanism using a proteomic approach. The well accepted tail-suspended rat model was used to simulate microgravity. The damage of rat small intestine was evaluated via histological and molecular test, and a label-free comparative proteomic strategy was used to determine the molecular mechanism. Simulated microgravity for 21 days damaged intestine barrier with decreased numbers of the goblet cells, large intercellular space, and down-regulated adhesion molecules, accompanied by increased intestinal permeability. Proteomic analysis identified 416 differentially expressed proteins and showed simulated microgravity dramatically down-regulated the adhesion molecules and deteriorated several pathways for metabolism, focal adhesion, and regulation of actin cytoskeleton. Western-blot analysis confirmed that myosin regulatory light chain (MLC) 12B was significantly down-regulated, while rho-associated protein kinase, myosin light chain kinase (MLCK), and phosphorylated MLC were dramatically up-regulated. Taken together, these data reveal that down-regulation of adhesion molecules and MLCK dependent up-regulation MLC phosphorylation mediate intestinal barrier dysfunction during simulated microgravity injury. Our results also indicate that regulation of epithelial MLCK is a potential target for the therapeutic treatment of microgravity injury.

Barrier-promoting efficiency of two bioactive flavonols quercetin and myricetin on rat intestinal epithelial (IEC-6) cells via suppressing Rho activation

Polyphenols are beneficial to human health because of their bio-activities. In this study, two flavonols quercetin and myricetin with or without heat treatment at 100 °C for 30 min were assessed for their barrier-promoting efficiency in rat intestinal epithelial (IEC-6) cells. The results indicated that the heated and unheated flavonols at dose levels of 2.5-20 μmol L-1 had a nontoxic effect on the cells treated for 24 and 48 h but enhanced the values of cell viability larger than 100% (especially at a dose level of 5 μmol L-1). Moreover, the cells exposed to these flavonols of 5 μmol L-1 for 24 and 48 h had improved barrier integrity compared to the control cells without any flavonol treatment, reflected by enhanced transepithelial electrical resistance and anti-bacterial effect but decreased paracellular permeability and bacterial translocation. Moreover, the results from both mRNA and protein expression verified 1.1-3.4 fold up-regulation of zonula occludens-1, occludin, and claudin-1 that are critical to tight junctions and barrier function of cells. Furthermore, the expression of other two proteins RhoA and ROCK in the treated cells was also down-regulated, demonstrating suppressed Rho activation and consequently barrier promotion via the RhoA/ROCK signaling pathway. Overall quercetin, due to its lower molecular polarity, mostly gave higher barrier-promoting efficiency than myricetin, while the heated flavonols were always less efficient than the unheated counterparts to promote barrier integrity of IEC-6 cells. It is thus highlighted that flavonols can provide barrier-promoting effects on intestinal epithelial cells with a promoting efficiency dependent on flavonol polarity; however, heat treatment especially excessive heat treatment of plant foods might lead to damaged flavonol activity.

Glutamine for Amelioration of Radiation and Chemotherapy Associated Mucositis during Cancer Therapy

Glutamine is a major dietary amino acid that is both a fuel and nitrogen donor for healing tissues damaged by chemotherapy and radiation. Evidence supports the benefit of oral (enteral) glutamine to reduce symptoms and improve and/or maintain quality of life of cancer patients. Benefits include not only better nutrition, but also decreased mucosal damage (mucositis, stomatitis, pharyngitis, esophagitis, and enteritis). Glutamine supplementation in a high protein diet (10 grams/day) + disaccharides, such as sucrose and/or trehalose, is a combination that increases glutamine uptake by mucosal cells. This increased topical effect can reduce painful mucosal symptoms and ulceration associated with chemotherapy and radiation in the head and neck region, esophagus, stomach and small intestine. Topical and oral glutamine seem to be the preferred routes for this amino acid to promote mucosal healing during and after cancer treatment.

Oral Glutamine Supplement Reduces Subjective Fatigue Ratings during Repeated Bouts of Firefighting Simulations

Wildland firefighting requires repetitive (e.g., consecutive work shifts) physical work in dangerous conditions (e.g., heat and pollution). Workers commonly enter these environments in a nonacclimated state, leading to fatigue and heightened injury risk. Strategies to improve tolerance to these stressors are lacking. Purpose: To determine if glutamine ingestion prior to and after consecutive days of firefighting simulations in the heat attenuates subjective ratings of fatigue, and evaluate if results were supported by glutamine-induced upregulation of biological stress responses. Methods: Participants (5 male, 3 female) ingested glutamine (0.15 g/kg/day) or a placebo before and after two consecutive days (separated by 24 h) of firefighter simulations in a heated chamber (35 °C, 35% humidity). Perceived fatigue and biological stress were measured pre-, post-, and 4 h postexercise in each trial. Results: Subjective fatigue was reduced pre-exercise on Day 2 in the glutamine group (p < 0.05). Peripheral mononuclear cell expression of heat shock protein 70 (HSP70) and serum antioxidants were elevated at 4 h postexercise on Day 1 in the glutamine trial (p < 0.05). Conclusions: Ingestion of glutamine before and after repeated firefighter simulations in the heat resulted in reduced subjective fatigue on Day 2, which may be a result of the upregulation of biological stress systems (antioxidants, HSPs). This response may support recovery and improve work performance.

Influence of starch sources and dietary protein levels on intestinal functionality and intestinal mucosal amino acids catabolism in broiler chickens

Background

There is growing interest in carbohydrate and protein nutrition to enhance the efficiency of animal production. Reduced-crude protein diets depress environmental pollution and feeding cost, but the challenge to their adoption is maintaining digestive function and growth performance of birds. The present study was conducted to evaluate the influence of different dietary starch sources and protein levels on intestinal functionality and mucosal amino acid catabolism.

Methods

Six dietary treatments, based on maize and soybean meal, were offered to 360 AA⁺ male chicks from 6 to 35 d post-hatch as a 3 × 2 factorial array. Either waxy rice or amylose was added to a conventional maize-soy diet to provide three sources of starch with different digestion rates and relatively high and low dietary protein levels. Growth performance, parameters of intestinal functionality and concentrations of free amino acid in the portal circulation were determined.

Results

In the grower phase, starch source influenced (P < 0.02) weight gain as diets containing amylose supported significantly higher weight gains than waxy rice. Significant increase of ileal ATP concentrations and Na⁺/K⁺-ATPase activity were found in amylose treatment. Also, amylose decreased BrdU positive cell numbers and down-regulated mRNA expression for CASP-3. GOT activity in the ileum was higher (P < 0.01) in birds offered low protein diets and there was a trend (P = 0.057) for waxy rice as a starch source to increase ileal GOT activities. There was a significant influence on the concentration of seventeen amino acids in the portal circulation with tryptophan the one exception. Waxy rice as a starch source generated 13.6% and 22.4% numerically higher concentrations of non-essential amino acids than maize and amylose, respectively.

Conclusions

Amino acid catabolism in the gut mucosa is subject to nutritional regulation. Given that amino acids can be spared from catabolism in the gut mucosa by supplementation of amylose, it follows their post-enteral availability would be improved and intestinal energy would be derived more efficiently from glucose.

Glutamine: Metabolism and Immune Function, Supplementation and Clinical Translation

Glutamine is the most abundant and versatile amino acid in the body. In health and disease, the rate of glutamine consumption by immune cells is similar or greater than glucose. For instance, in vitro and in vivo studies have determined that glutamine is an essential nutrient for lymphocyte proliferation and cytokine production, macrophage phagocytic plus secretory activities, and neutrophil bacterial killing. Glutamine release to the circulation and availability is mainly controlled by key metabolic organs, such as the gut, liver, and skeletal muscles. During catabolic/hypercatabolic situations glutamine can become essential for metabolic function, but its availability may be compromised due to the impairment of homeostasis in the inter-tissue metabolism of amino acids. For this reason, glutamine is currently part of clinical nutrition supplementation protocols and/or recommended for immune suppressed individuals. However, in a wide range of catabolic/hypercatabolic situations (e.g., ill/critically ill, post-trauma, sepsis, exhausted athletes), it is currently difficult to determine whether glutamine supplementation (oral/enteral or parenteral) should be recommended based on the amino acid plasma/bloodstream concentration (also known as glutaminemia). Although the beneficial immune-based effects of glutamine supplementation are already established, many questions and evidence for positive in vivo outcomes still remain to be presented. Therefore, this paper provides an integrated review of how glutamine metabolism in key organs is important to cells of the immune system. We also discuss glutamine metabolism and action, and important issues related to the effects of glutamine supplementation in catabolic situations.

Glutamine: Metabolism and Immune Function, Supplementation and Clinical Translation

Glutamine is the most abundant and versatile amino acid in the body. In health and disease, the rate of glutamine consumption by immune cells is similar or greater than glucose. For instance, in vitro and in vivo studies have determined that glutamine is an essential nutrient for lymphocyte proliferation and cytokine production, macrophage phagocytic plus secretory activities, and neutrophil bacterial killing. Glutamine release to the circulation and availability is mainly controlled by key metabolic organs, such as the gut, liver, and skeletal muscles. During catabolic/hypercatabolic situations glutamine can become essential for metabolic function, but its availability may be compromised due to the impairment of homeostasis in the inter-tissue metabolism of amino acids. For this reason, glutamine is currently part of clinical nutrition supplementation protocols and/or recommended for immune suppressed individuals. However, in a wide range of catabolic/hypercatabolic situations (e.g., ill/critically ill, post-trauma, sepsis, exhausted athletes), it is currently difficult to determine whether glutamine supplementation (oral/enteral or parenteral) should be recommended based on the amino acid plasma/bloodstream concentration (also known as glutaminemia). Although the beneficial immune-based effects of glutamine supplementation are already established, many questions and evidence for positive in vivo outcomes still remain to be presented. Therefore, this paper provides an integrated review of how glutamine metabolism in key organs is important to cells of the immune system. We also discuss glutamine metabolism and action, and important issues related to the effects of glutamine supplementation in catabolic situations.

Residual gastric volume evaluation with ultrasonography after ingestion of carbohydrate- or carbohydrate plus glutamine-enriched beverages: a randomized, crossover clinical trial with healthy volunteers

BACKGROUND

- Abbreviation of preoperative fasting to 2 hours with maltodextrin (CHO)-enriched beverage is a safe procedure and may enhance postoperative recovery. Addition of glutamine (GLN) to CHO beverages may include potential benefits to the metabolism. However, by adding a nitrogenous source to CHO beverages, gastric emptying may be delayed and increase the risk of bronchoaspiration during anesthesia.

OBJECTIVE

- In this study of safety, we aimed at investigating the residual gastric volume (RGV) 2 hours after the intake of either CHO beverage alone or CHO beverage combined with GLN.

METHODS

- We performed a randomized, crossover clinical trial. We assessed RGV by means of abdominal ultrasonography (US) in 20 healthy volunteers (10 males and 10 females) after an overnight fast of 8 hours. Then, they were randomized to receive 600 mL (400 mL immediately after US followed by another 200 mL 2 hours afterwards) of either CHO (12.5% maltodextrin) or CHO-GLN (12.5% maltodextrin plus 15 g GLN). Two sequential US evaluations were done at 120 and 180 minutes after ingestion of the second dose. The interval of time between ingestion of the two types of beverages was 2 weeks.

RESULTS

- The mean (SD) RGV observed after 8 hours fasting (13.56±13.25 mL) did not statistically differ (P>0.05) from the RGV observed after ingesting CHO beverage at both 120 (16.32±11.78 mL) and 180 minutes (14.60±10.39 mL). The RGV obtained at 120 (15.63±18.83 mL) and 180 (13.65±10.27 mL) minutes after CHO-GLN beverage also was not significantly different from the fasting condition.

CONCLUSION

- The RGV at 120 and 180 minutes after ingestion of CHO beverage combined with GLN is similar to that observed after an overnight fast.

Outpatient Transfusion Practice and Factors Leading to Inpatient Transfusion in a Pediatric Hematology/Oncology Program

Oral mucositis continues to be a common and debilitating side effect of the conditioning regimens that use high-dose chemotherapy with or without radiation for pediatric bone marrow transplantation. Limited interventions have demonstrated success in preventing or treating it. Administration of glutamine, which is a nitrogen-rich amino acid found in the body, has emerged as a possible method of preventing oral mucositis in patients undergoing bone marrow transplantation. Numerous studies have looked at the effects of oral glutamine supplementation during bone marrow transplant. The purpose of this article is to describe glutamine and how it functions, review the literature regarding the use of oral glutamine in the prevention of oral mucositis in bone marrow transplantion, discuss the administration concerns related to the pediatric setting, and stress the importance of the nurse's role at the bedside. Nurses working in pediatric bone marrow transplant play a key role in the assessment of oral mucositis, administration of oral glutamine, and education of the patient and family.

The Dipeptide Alanyl-Glutamine Prevents Intestinal Mucosal Atrophy in Parenterally Fed Rats

This study was performed to determine whether the addition of alanyl-glutamine (Ala-Gln) can prevent intestinal mucosal atrophy induced by standard solution of total parenteral nutrition (S-TPN). Forty-one male Sprague-Dawley rats weighing 250 g were randomly divided into four groups: group I was killed after overnight fasting; group II received S-TPN. The other groups received S-TPN supplemented with amino acids other than glutamine (group III) or supplemented with Ala-Gln 2 g/100 mL (group IV); both solutions were isocaloric and isonitrogenous. After 1 week of TPN the rats were killed, and the duodenum, proximal jejunum, mid-small bowel, and distal ileum were obtained for morphologic and functional analysis. Weight gain did not differ significantly among these four groups, and there was no difference in nitrogen balance between groups III and IV. Serum glutamine in group IV (102.8 +/- 13.3 mumol/dL) was significantly increased (p less than .05) compared with groups I, II, and III (66.2 +/- 3.9, 55.7 +/- 7.8, and 61.3 +/- 10.8 mumol/dL, respectively). Mucosal wet weight, protein, RNA, sucrase, and maltase of group IV were significantly increased (p less than .05) compared with groups II and III. Villus height was significantly increased (p less than .05) in the jejunum of group IV rats compared with groups II and III, but not in any other segments of the intestine. No significant changes were observed in crypt depth among all groups. Diamine oxidase in groups II, III, and IV was significantly decreased (p less than .05) compared with group I in all segments except for the ileum.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of L-Glutamine oral supplementation on prostate of irradiated rats

Objectives

To investigate the protective effect of L-Glutamine in animals undergone to ventral radiation when the target organ is not the prostate.

Materials and Methods

Wistar rats were divided into groups of 10 animals each: Controls (C), maintained under standard conditions and not exposed to radiation, Radiated group (R) undergone to abdominal radiation only and Radiated plus supplemented by L-glutamine group (R+G). The animals of group R+G were supplemented with L-glutamine at the beginning of the experiment until death in the 22nd day. The ventral prostate was dissected and processed for morphometrical analysis. The epithelial height, collagen density and acinar area were objectively assessed in histological sections.

Results

Epithelial height was significantly reduced in R group in comparison to C group (p= 0.005). However, there was no statistical difference between the C and R+G groups. Collagen surface density in the C and R groups were not statistically different, but a significant difference was observed when comparing groups R+G and R (p= 0.040). The R+G group values did not differ significantly from C group. The acinar prostate area of group R was similar to that of C (p= 0.971), but in R+G it was significantly reduced when compared with the C (p= 0.038) and R (p= 0.001) groups.

Conclusions

Pelvic radiation promotes structural modifications in ventral prostate of rats, which can be reduced by L-Glutamine.

Impact of Protein Nutritional Status on Plasma BNP in Elderly Patients

BACKGROUND

Previous studies have demonstrated that the levels of B-type natriuretic peptide (BNP) in plasma are negatively correlated with Body Mass Index (BMI) whereas lean body mass is also closely related to plasma BNP. The purpose of this study is to determine the effect of protein nutritional status on plasma BNP in aged patients.

METHODS AND RESULTS

The cross-sectional study was applied and the anthropometric measurement and nutritional biochemical test was performed in 1118 elderly inpatients in a stable condition were enrolled in the study (mean age, 75 years; 54% women). The partial correlation and multivariate regression analysis were conducted to analyze the relation of plasma BNP with covariates. After adjustment for confounding factors such as age, smoking and coexisting diseases, we found that the concentrations of BNP were independently associated with serum albumin (β=-0.065, P<0.001), serum total cholesterol (β=-0.097, P<0.012) and calf circumference (β=-0.032, P<0.014) in female patients, and associated with the serum albumin (β=-0.051, P<0.001), prealbumin (β=-2.177, P<0.026), mid-arm circumference (β=-0.062, P<0.001) and grip strength (β=-0.100, P<0.048) in male patients. Every 1 gram per liter of increased serum albumin corresponded to the reduced plasma BNP in male patients by 13.9% (OR 0.861, 95% CI 0.817, 0.909) and in female patients by 13.4% (OR 0.866, 95% CI 0.819, 0.916).

CONCLUSIONS

Our study suggests that plasma BNP is negatively correlated with muscle mass, and it is also related to muscle force in male patients. The serum albumin is an independent determinant factor of BNP in both men and women. These findings suggest that good protein nutritional status could be beneficial in maintaining the cardiac function in elder population.

Key Roles of Glutamine Pathways in Reprogramming the Cancer Metabolism

Glutamine (GLN) is commonly known as an important metabolite used for the growth of cancer cells but the effects of its intake in cancer patients are still not clear. However, GLN is the main substrate for DNA and fatty acid synthesis. On the other hand, it reduces the oxidative stress by glutathione synthesis stimulation, stops the process of cancer cachexia, and nourishes the immunological system and the intestine epithelium, as well. The current paper deals with possible positive effects of GLN supplementation and conditions that should be fulfilled to obtain these effects. The analysis of GLN metabolism suggests that the separation of GLN and carbohydrates in the diet can minimize simultaneous supply of ATP (from glucose) and NADPH2 (from glutamine) to cancer cells. It should support to a larger extent the organism to fight against the cancer rather than the cancer cells. GLN cannot be considered the effective source of ATP for cancers with the impaired oxidative phosphorylation and pyruvate dehydrogenase inhibition. GLN intake restores decreased levels of glutathione in the case of chemotherapy and radiotherapy; thus, it facilitates regeneration processes of the intestine epithelium and immunological system.

Refining the ammonia hypothesis: a physiology-driven approach to the treatment of hepatic encephalopathy

Hepatic encephalopathy (HE) is one of the most important complications of cirrhosis and portal hypertension. Although the etiology is incompletely understood, it has been linked to ammonia directly and indirectly. Our goal is to review for the clinician the mechanisms behind hyperammonemia and the pathogenesis of HE to explain the rationale for its therapy. We reviewed articles collected through a search of MEDLINE/PubMed, Cochrane Database of Systematic Reviews, and Google Scholar between October 1, 1948, and December 8, 2014, and by a manual search of citations within retrieved articles. Search terms included hepatic encephalopathy, ammonia hypothesis, brain and ammonia, liver failure and ammonia, acute-on-chronic liver failure and ammonia, cirrhosis and ammonia, portosytemic shunt, ammonia and lactulose, rifaximin, zinc, and nutrition. Ammonia homeostatsis is a multiorgan process involving the liver, brain, kidneys, and muscle as well as the gastrointestinal tract. Indeed, hyperammonemia may be the first clue to poor functional reserves, malnutrition, and impending multiorgan dysfunction. Furthermore, the neuropathology of ammonia is critically linked to states of systemic inflammation and endotoxemia. Given the complex interplay among ammonia, inflammation, and other factors, ammonia levels have questionable utility in the staging of HE. The use of nonabsorbable disaccharides, antibiotics, and probiotics reduces gut ammoniagenesis and, in the case of antibiotics and probiotics, systemic inflammation. Nutritional support preserves urea cycle function and prevents wasting of skeletal muscle, a significant site of ammonia metabolism. Correction of hypokalemia, hypovolemia, and acidosis further assists in the reduction of ammonia production in the kidney. Finally, early and aggressive treatment of infection, avoidance of sedatives, and modification of portosystemic shunts are also helpful in reducing the neurocognitive effects of hyperammonemia. Refining the ammonia hypothesis to account for these other factors instructs a solid foundation for the effective treatment and prevention of hepatic encephalopathy.

Metabolic phenotyping of an adoptive transfer mouse model of experimental colitis and impact of dietary fish oil intake

Inflammatory bowel diseases are acute and chronic disabling inflammatory disorders with multiple complex etiologies that are not well-defined. Chronic intestinal inflammation has been linked to an energy-deficient state of gut epithelium with alterations in oxidative metabolism. Plasma-, urine-, stool-, and liver-specific metabonomic analyses are reported in a naïve T cell adoptive transfer (AT) experimental model of colitis, which evaluated the impact of long-chain n-3 polyunsaturated fatty acid (PUFA)-enriched diet. Metabolic profiles of AT animals and their controls under chow diet or fish oil supplementation were compared to describe the (i) consequences of inflammatory processes and (ii) the differential impact of n-3 fatty acids. Inflammation was associated with higher glycoprotein levels (related to acute-phase response) and remodeling of PUFAs. Low triglyceride levels and enhanced PUFA levels in the liver suggest activation of lipolytic pathways that could lead to the observed increase of phospholipids in the liver (including plasmalogens and sphingomyelins). In parallel, the increase in stool excretion of most amino acids may indicate a protein-losing enteropathy. Fecal content of glutamine was lower in AT mice, a feature exacerbated under fish oil intervention that may reflect a functional relationship between intestinal inflammatory status and glutamine metabolism. The decrease in Krebs cycle intermediates in urine (succinate, α-ketoglutarate) also suggests a reduction in the glutaminolytic pathway at a systemic level. Our data indicate that inflammatory status is related to this overall loss of energy homeostasis.

L-Glutamine deprivation induces autophagy and alters the mTOR and MAPK signaling pathways in porcine intestinal epithelial cells

L-Glutamine (Gln) is an essential amino acid for intestinal growth and integrity. However, the underlying molecular mechanisms are not fully known. In the present study, porcine intestinal epithelial cells (IPEC-1) were used to test the hypothesis that autophagy is induced by Gln deprivation and inhibited by Gln supplementation. After a 2-day period of growth in normal medium, IPEC-1 cells were transferred to a Gln-free custom-made DMEM. Cell numbers, the distribution of autophagosomes, the abundance of the protein for an autophagy marker LC3B, as well as abundances of the mTOR and MAPK proteins during an 8-h period were determined. Furthermore, the rescue effect of 5 mM Gln was evaluated. Our results showed that Gln deprivation reduced the cell number, while enhancing the accumulation of autophagosomes and the expression of LC3B-II in IPEC-1 cells within 8 h. The concentrations of Glu, Asp, Cit, Arg, Leu, Ile, Val, Ala, β-Ala, Orn, Phe, Met and Ser in the culture medium were altered by Gln deprivation. Further analysis revealed that Gln deficiency inactivated, but Gln supplementation activated, the mTOR and MAPK/ERK signaling pathways. Collectively, our findings support the notion that Gln deficiency induces autophagy and disturbs amino acid metabolism in intestinal epithelial cells, as well as attenuated their mTOR and MAPK/ERK signaling pathways to inhibit protein synthesis and cell proliferation.

Tubular scaffolds of gelatin and poly(ε-caprolactone)-block-poly(γ-glutamic acid) blending hydrogel for the proliferation of the primary intestinal smooth muscle cells of rats

The proper regeneration of intestinal muscle for functional peristalsis is the most challenging aspect of current small intestine tissue engineering. This study aimed to fabricate a hydrogel scaffold for the proliferation of intestinal smooth muscle cells (ISMCs). Tubular porous scaffolds of 10-20 wt% gelatin and 0.05-0.1 wt% poly(ε-caprolactone)-block-poly(γ-glutamic acid) blending hydrogel were cross-linked by carbodiimide and succinimide in an annular space of a glass mold. The scaffolds with higher gelatin contents degraded slower in the phosphate buffer solution. In rheological measurements, the hydrated scaffolds were elastic (all tangent delta <0.45); they responded differentially to frequency, indicating a complete viscoelastic property that is beneficial for soft tissue regeneration. Isolated rat ISMCs, with the characteristic biomarkers α-SMA, calponin and myh11, were loaded into the scaffolds by using either static or centrifugal methods. The average cell density inside the scaffolds increased in a time-dependent manner in most scaffolds of both seeding groups, although at early time points (seven days) the centrifugal seeding method trapped cells more efficiently and yielded a higher cell density than the static seeding method. The static seeding method increased the cell density from 7.5-fold to 16.3-fold after 28 days, whereas the centrifugal procedure produced a maximum increase of only 2.4-fold in the same period. In vitro degradation data showed that 50-80% of the scaffold was degraded by the 14th day. However, the self-secreted extracellular matrix maintained the integrity of the scaffolds for cell proliferation and spreading for up to 28 days. Confocal microscopic images revealed cell-cell contacts with the formation of a 3D network, demonstrating that the fabricated scaffolds were highly biocompatible. Therefore, these polymeric biomaterials hold great promise for in vivo applications of intestinal tissue engineering.

Effects of alkali supplementation and vitamin D insufficiency on rat skeletal muscle

Data on the independent and potential combined effects of acid-base balance and vitamin D status on muscle mass and metabolism are lacking. We investigated whether alkali supplementation with potassium bicarbonate (KHCO3), with or without vitamin D3 (± VD3), alters urinary nitrogen (indicator of muscle proteolysis), muscle fiber cross-sectional area (FCSA), fiber number (FN), and anabolic (IGF-1, Akt, p70s6k) and catabolic (FOXO3a, MURF1, MAFbx) signaling pathways regulating muscle mass. Thirty-six, 20-month-old, Fischer 344/Brown-Norway rats were randomly assigned in a 2 × 2 factorial design to one of two KHCO3-supplemented diets (± VD3) or diets without KHCO3 (± VD3) for 12 weeks. Soleus, extensor digitorum longus (EDL), and plantaris muscles were harvested at 12 weeks. Independent of VD3 group, KHCO3 supplementation resulted in 35 % lower mean urinary nitrogen to creatinine ratio, 10 % higher mean type I FCSA (adjusted to muscle weight), but no statistically different mean type II FCSA (adjusted to muscle weight) or FN compared to no KHCO3. Among VD3-replete rats, phosphorylated-Akt protein expression was twofold higher in the KHCO3 compared to no KHCO3 groups, but this effect was blunted in rats on VD3-deficient diets. Neither intervention significantly affected serum or intramuscular IGF-1 expression, p70s6k or FOXO3a activation, or MURF1 and MAFbx gene expression. These findings provide support for alkali supplementation as a promising intervention to promote preservation of skeletal muscle mass, particularly in the setting of higher vitamin D status. Additional research is needed in defining the muscle biological pathways that are being targeted by alkali and vitamin D supplementation.

P38MAP kinase, but not phosphoinositol-3 kinase, signal downstream of glutamine-mediated fibronectin-integrin signaling after intestinal injury

Background

Glutamine appears to mediate protection against gut injury via multiple pathways. These include fibronectin-integrin, PI3-K/MAPK pathways, and activation of heat shock protein (HSP) response. We hypothesize there may be a relationship between these pathways mediating glutamine’s protection in intestinal epithelial-6 cells after heat stress. We assessed whether p38MAPK and PI3-K/Akt signaling are involved in glutamine’s cytoprotective mechanism and the role they play in glutamine-mediated protection in conjunction with fibronectin-integrin osmosignaling after hyperthermia.

Methods

Intestinal epithelial cells were treated for 15 min with glutamine, with/without the fibronectin-integrin interaction inhibitor GRGDSP, inactive control peptide GRGESP, p38MAPK inhibitor SB203580, or PI3-K/Akt inhibitor LY294002 under basal (37°C) and stressed (43°C or 44°C) conditions. Cell survival was measured via MTS assay 24 h post-heat stress (44°C × 50 min). Total p38MAPK, [T(P)¹⁸⁰/Y(P)¹⁸²]p38MAPK, total Akt, [S(P)⁴⁷³]Akt, HSP70, FN, and caspase-3 levels were determined via Western blot after non-lethal HS (43°C × 50 min). Additionally, HSP70 levels were assessed via Western blot and ELISA.

Results

We were able to show that GRGDSP and LY294002 attenuated glutamine’s protective effect. However, SB203580 increased cell survival after heat stress. LY294002 attenuated glutamine-mediated increases in fibronectin and in HSP70 expression after hyperthermia. GRGDSP increased glutamine-mediated attenuations in p38MAPK phosphorylation, but had no effect on glutamine-mediated augmentations in Akt phosphorylation.

Conclusions

These data suggest that glutamine is protective after heat stress by activating PI3-K/Akt signaling preventing fibronectin-integrin expression and increasing HSP70 expression. Furthermore, dephosphorylation of p38MAPK after heat stress plays an important role in glutamine-mediated cellular protection. However, p38MAPK, but not PI3-K/Akt, signals downstream of glutamine-mediated fibronectin-integrin signaling after hyperthermia.

Impact of nutrition on muscle mass, strength, and performance in older adults

Muscle strength plays an important role in determining risk for falls, which result in fractures and other injuries. While bone loss has long been recognized as an inevitable consequence of aging, sarcopenia-the gradual loss of skeletal muscle mass and strength that occurs with advancing age-has recently received increased attention. A review of the literature was undertaken to identify nutritional factors that contribute to loss of muscle mass. The role of protein, acid-base balance, vitamin D/calcium, and other minor nutrients like B vitamins was reviewed. Muscle wasting is a multifactorial process involving intrinsic and extrinsic alterations. A loss of fast twitch fibers, glycation of proteins, and insulin resistance may play an important role in the loss of muscle strength and development of sarcopenia. Protein intake plays an integral part in muscle health and an intake of 1.0-1.2 g/kg of body weight per day is probably optimal for older adults. There is a moderate [corrected] relationship between vitamin D status and muscle strength. Chronic ingestion of acid-producing diets appears to have a negative impact on muscle performance, and decreases in vitamin B12 and folic acid intake may also impair muscle function through their action on homocysteine. An adequate nutritional intake and an optimal dietary acid-base balance are important elements of any strategy to preserve muscle mass and strength during aging.

Inflammatory cytokine TNF-α inhibits Na(+)-glutamine cotransport in intestinal epithelial cells

Glutamine (Gln), a preferred fuel source for enterocytes, is critical for intestinal epithelial cell integrity and barrier function. Chronic enteritis inhibits apical Na(+)-Gln cotransport. It is not known whether inflammatory cytokines that are secreted during inflammation inhibit Na(+)-Gln cotransport. Thus, this study aimed to examine whether TNF-α would affect apical Na(+)-Gln cotransport in intestinal epithelial cells. In this study, the presence of Na(+)-Gln cotransport was established by measuring Gln uptake in 10 days postconfluent IEC-6 cells grown on transwell plates. Cation, amino acid specificity, and siRNA transfection studies established that Na(+)-Gln cotransport is mediated via B(0)AT1. Immunoblotting and immunofluorescence studies established the apical membrane localization of B(0)AT1 in IEC-6 cells. Tumour necrosis factor α (TNF-α) inhibited Na(+)-Gln cotransport in a concentration- and time-dependent manner with an inhibitory concentration of 1.53 nmol·L(-1). Quantitative real-time PCR and Western blot analyses indicated that TNF-α did not alter B(0)AT1-specific transcripts or protein expression level. Kinetic studies revealed that TNF-α inhibited Na(+)-Gln cotransport by reducing the affinity of the cotransporters for Gln, and this effect was antagonized by genistein. Thus, we conclude that the TNF-α inhibition of Na(+)-Gln cotransport occurs at the post-translational level, and that the IEC-6 cell line is an excellent system to study the role of cytokines in Na(+)-Gln cotransport.

Female distance runners show a different response to post-workout consumption of wheat gluten hydrolysate compared to their male counterparts

Wheat gluten hydrolysate (WGH) is rich in glutamyl residue; glutamine is considered a conditionally essential amino acid under physical stress. WGH has been reported to suppress post-exercise rises in serum creatine kinase in male distance runners. This study aimed to reproduce the effects in female distance runners under similar conditions. The study was conducted in a double-blinded crossover manner. Six female collegiate distance runners ingested WGH or a placebo after a 2-h run at an intensity estimated as 60-70% of their maximum oxygen uptake. Blood was sampled before, immediately after, and at 10 and 24 h after the run. Unlike those in male runners, serum creatine kinase (CK) increased slightly, with a peak at 10 h after the run, while plasma glutamine kept declining. The anti-inflammatory effect of WGH was not evident since the post-exercise elevation of CK was ambiguous. Plasma glutamine concentrations also showed a different kinetics from that in men.

Enhancing apoptotic cell clearance mitigates bacterial translocation and promotes tissue repair after gut ischemia-reperfusion injury

A key aspect of intestinal ischemia/reperfusion (I/R) injury is the increased occurrence of apoptotic cell death in the gut. Insufficient clearance of apoptotic cells leads to increased inflammation and impaired tissue repair. Our recent studies have shown that administration of milk fat globule-epidermal growth factor-factor 8 (MFG-E8), a crucial molecule for apoptotic cell clearance, reduces apoptosis and inflammation under various disease conditions. The purpose of this study was to determine whether MFG-E8 reduces bacterial translocation and promotes tissue repair in a mouse model of gut I/R. Gut ischemia was induced by placing a microvascular clip across the superior mesenteric artery for 90 min in male adult mice. After removing the clip, recombinant murine MFG-E8 (rmMFG-E8) (0.4 µg/20 g BW) or normal saline (Vehicle) was intraperitoneally injected. At 4 h after reperfusion, apoptosis in the gut was measured by TUNEL staining. The mesenteric lymph node (MLN) complex was homogenized and plated on chocolate agar plates for bacterial culture. Neutrophil infiltration was assessed by examining myeloperoxidase (MPO) activity in the gut. Vascular endothelial growth factor (VEGF) levels in the gut, an indicator of tissue repair, were measured by western blotting. Out results showed that TUNEL-positive staining in the gut increased significantly in gut I/R vehicle-treated mice. Treatment with rmMFG-E8 markedly suppressed the number of apoptotic cells. Bacterial translocation to the MLN was minimal in sham mice, but was extensive in gut I/R vehicle-treated mice. rmMFG-E8 treatment significantly reduced bacterial translocation to the MLN. Similarly, gut I/R induced a significant increase in intestinal MPO activities in vehicle-treated mice. rmMFG-E8 treatment markedly reduced the increase in intestinal MPO activities after gut I/R. Intestinal levels of VEGF decreased significantly at 4 h after gut I/R. rmMFG-E8 treatment significantly increased intestinal VEGF levels. Thus, enhancing apoptotic cell clearance by rmMFG-E8 mitigates bacterial translocation, inhibits neutrophil infiltration and promotes tissue repair after gut I/R. Enhancing apoptotic cell clearance can be a novel concept in the treatment of gut I/R injury.

An in silico model of enterocytic glutamine to citrulline conversion pathway

Enterocyte is one of the main sites of amino acids metabolism and particularly of the citrulline biosynthesis. Working at the cellular scale and applying ordinary differential equations (ODEs) formalism, we have built a mathematical model of the enterocytic glutamine to citrulline conversion in the fasting state. This model enables us to test different physiopathological scenarios of enzyme activity loss. Results from two different approaches were compared: a standard approach (KA) based on the Michaelis-Menten assumptions and an association-dissociation approach (VH) based on the kinetic mass action law. For both approaches, ODEs system was numerically solved using Mathematica™. In both cases, the model correctly predicts the physiological plasma citrulline steady-state, but the two approaches present clear differences for metabolites of enzymes having a complex mechanism, challenging the validity of the KA approach in such cases. When physiopathological scenarios of enzyme activity loss are simulated, both approaches predict a very sharp transition from the physiological citrulline plasma level to the lack of its production: the concentration profiles of these simulations show a clear threshold of which characteristics vary with the involved enzyme. Moreover, amongst all enzymes included in the model, the ornithine aminotransferase (OAT) shows the highest sensitivity in the system whatever the approach used. This model points out the limits of the Michaelis-Menten approach to model complex enzyme mechanisms. It highlights the key role of OAT in the studied citrulline synthesis pathway and also suggests an order of magnitude about the optimal ratio of enzyme concentrations in this pathway.

A lepidopteran aminoacylase (L-ACY-1) in Heliothis virescens (Lepidoptera: Noctuidae) gut lumen hydrolyzes fatty acid-amino acid conjugates, elicitors of plant defense

Fatty acid-amino acid conjugates (FACs) have been identified in Lepidopteran larvae as elicitors of plant defenses. Plant responses include the production of primary defense compounds and induction of secondary defense strategies including attraction of parasitoid wasps. These elicitors are present despite fitness costs, suggesting that they are important for the larvae's survival. In order to exploit FAC-mediated plant defense responses in agricultural settings, an understanding of FAC purpose and metabolism is crucial. To clarify their role, enzymes involved in this metabolism are being investigated. In this work a previously undiscovered FAC hydrolase was purified from Heliothis virescens frass by liquid chromatography and PAGE techniques and was identified as an aminoacylase-like protein (L-ACY-1) using MALDI-ToF/ToF and Edman sequencing. The full length gene was cloned and expressed in Escherichia coli and a polyclonal antibody against L-ACY-1 was made. L-ACY-1 was confirmed to be responsible for FAC hydrolysis activity through inhibition of N-linolenoyl-l-glutamine hydrolysis by titration with the polyclonal anti-L-ACY-1 antibody. L-ACY-1 activity is dependent on a divalent cation. This is the first time an aminoacylase has been described from an insect. L-ACY-1 appears to play a vastly different role in insects than ACYs do in mammals and may be involved in maintaining glutamine supplies for gut tissue metabolism. Identification of L-ACY-1, a FAC hydrolase, clarifies a previously uncharacterized portion of FAC metabolism.

Nutritional therapy in critically ill and injured patients

Nutritional support of critically ill or injured patients has undergone significant advances in the last few decades. These advances are the direct result of the growing scientific progress and increased knowledge of the biology and biochemistry of key metabolic and nutrient changes induced by injury, sepsis, and other critical illnesses, both in adults and children. As this knowledge has increased, the science of nutritional support has become more disease based and disorder based. This article discusses protein and nitrogen metabolism in critically ill patients, immunomodulation, and the key nutrients involved in an immune-enhancing diet.

Parenteral nutrition: Revisited

The prevalence of malnutrition among critically ill patients, especially those with a protracted clinical course, has remained largely unchanged over the last two decades. The metabolic response to stress, injury, surgery, or inflammation cannot be accurately predicted and these metabolic alterations may change during the course of illness. Both underfeeding and overfeeding are common in intensive care units (ICU), resulting in large energy and other nutritional imbalances. Systematic research and clinical trials on various aspects of nutritional support in the ICU are limited and make it challenging to compile evidence-based practice guidelines.

Cellular changes in hepatocytes and intestinal endothelium after hepatoduodenal ligament occlusion and protective effects of caspase inhibition

INTRODUCTION

Hepatic vascular control is used by many surgeons to prevent massive hemorrhage during hepatectomy. However, this may carry a risk of ischemic damage to the hepatocytes. Another major drawback of intraoperative occlusion of the hepatoduodenal ligament is portal stasis with resultant intestinal congestion which may cause adverse effects on the intestinal functions. CD44 is a transmembrane glycoprotein present in many types of epithelial cells. By mediating the attachment of dividing crypt cells to the basal lamina via hyaluronan, CD44 is considered to play a role in maintaining the intestinal villus integrity. Apoptosis is a pathway of cell death orchestrated by a family of proteases called caspases. ZVAD-fmk is a cell-permeable irreversible inhibitor of caspase and might block the processing of many caspases. This study is designed with the purpose to evaluate the impact of intraoperative occlusion of the hepatoduodenal ligament on hepatocyte and intestine functions and also to evaluate the potential influence of ZVAD-fmk on the hepatocyte and intestine functions.

MATERIALS AND METHODS

Male Sprague-Dawley rats were randomized to 5 groups. Group 1(C) underwent sham operation. Group 2 (HDL30) underwent occluding the hepatoduodenal ligament by for 30 minutes. Group 3 (HDL 15) underwent occluding the hepatoduodenal ligament by for 15 minutes, releasing for 5 minutes, underwent occlusion for another 15 minutes. Group 4 (ZHDL30) first received ZVAD-fmk, then underwent occluding the hepatoduodenal ligament by for 30 minutes. Group 5 (ZHDL15) first received ZVAD-fmk, then underwent occluding the hepatoduodenal ligament for 15 minutes, releasing for 5 minutes, underwent occlusion for another 15 minutes. After removing the temporary occlusion, liver tissue and proximal jejunum were harvested. Hepatocyte and intestine apoptosis were quantitated using the TUNEL method. CD 44 status of jejunum were determined by immunohistochemical staining.

RESULTS

Hepatocyte apoptosis was significantly increased in group (HDL30) and group (HDL15) when compared with group (C). ZVAD-fmk effectively attenuated this phenomenon in both groups. There was no significant difference between group (HDL30) and group (HDL15). Jejunal apoptosis was significantly increased in group (HDL30) and group (HDL15) when compared with group (C). ZVAD-fmk effectively attenuated this phenomenon in both groups. There was no significant difference between group (HDL30) and group (HDL15). CD44 expression on jejunum was significantly increased in group (HDL30) and group (HDL15) when compared with group (C). ZVAD-fmk failed to effectively diminish this phenomenon.

CONCLUSION

Occlusion of the hepatoduodenal ligament significantly increased both hepatocyte and jejunal apoptosis and pretreatment with ZVAD-fmk could effectively diminish such phenomenon. CD44 expression on jejunum was also significantly increased by intraoperative occlusion of the hepatoduodenal ligament, yet pretreatment with ZVAD-fmk failed to show significant effect on such phenomenon.

Human growth hormone and glutamine for patients with short bowel syndrome

BACKGROUND

There has been clinical enthusiasm for treating short bowel patients with human recombinant growth hormone and/or glutamine in hopes of reducing parenteral nutrition dependency. It has been more than a decade since Byrne and colleagues reported enhanced absorption of nutrients, improved weight gain, and reduction in parenteral nutrition requirements with the administration of a combination of human growth hormone (HGH) and glutamine in patients with short bowel syndrome. Other studies have reported inconsistent results.

OBJECTIVES

The purpose of this systematic review was to evaluate the efficacy of growth hormone with or without glutamine supplementation for adult patients with short bowel syndrome.

SEARCH STRATEGY

Electronic searches were performed to identify all publications describing randomised controlled trials of the use of human growth hormone with or without glutamine for the treatment of patients with short bowel syndrome.

SELECTION CRITERIA

Randomised controlled trials of human growth hormone with or without glutamine for patients with short bowel syndrome were considered for inclusion.

DATA COLLECTION AND ANALYSIS

Two authors independently extracted data from the published studies. The statistical analyses were performed using RevMan 5 software. Follmann's method was used for cross-over studies.

MAIN RESULTS

Five studies were included in the review. Human growth hormone with or without glutamine appears to provide benefit in terms of increased weight (MD 1.66 Kg; 95% CI 0.69 to 2.63;P = 0.0008), lean body mass (MD 1.93 Kg; 95% CI 0.97 to 2.90; P = 0.0001) energy absorption (MD 4.42 Kcal; 95% CI 0.26 to 8.58; P = 0.04) and nitrogen absorption (MD 44.85 g; 95%CI 0.20 to 9.49; P = 0.04) for patients with short bowel syndrome. The single RCT that focused on parenteral nutrition (PN) requirements demonstrated decreased PN volume and calories and number of infusions in patients who received HGH with or without glutamine supplementation. Only patients who received HGH with glutamine maintained statistically significant PN reductions at 3 month follow-up.

AUTHORS' CONCLUSIONS

The results suggest a positive effect of human growth hormone on weight gain and energy absorption. However, in the majority of trials, the effects are short-lived returning to baseline shortly after cessation of therapy. The temporary benefit calls into question the clinical utility of this treatment. To date, the evidence is inconclusive to recommend this therapy. Consideration should be made to studying patients during the active phase of intestinal adaptation rather than in the setting of chronic intestinal failure. The role of HGH in paediatric short bowel syndrome remains unknown.

Plasma glutamine concentrations in the horse following feeding and oral glutamine supplementation

REASONS FOR PERFORMING STUDY

Pharmacological benefits of glutamine supplementation have been shown in athletically and clinically stressed human subjects. In the horse, infection and intense exercise have also been shown to significantly decrease plasma glutamine concentrations, but little is known on how best to supplement.

OBJECTIVE

To evaluate whether ingestion of different foodstuffs, with or without L-glutamine (G) or a peptide (Pep) containing 31.5% w/w G in a water-stable form, could affect plasma glutamine concentrations (P-GC).

MATERIALS AND METHODS

Nine feeds (molassed sugar beet-pulp (mSB); naked oats (nO); commercial mix (CM); mSB with 30 or 60 mg/kg bwt G or the G-molar equivalent of Pep; and CM with 60 mg/kg bwt G or equivalent Pep) were offered to 6 healthy mature horses on different days following overnight food restriction. The changes in P-GC were monitored for 8 h post feeding.

RESULTS

After 1.5 h mean +/- s.d. AP-GC were -0.9 +/- 10.2% (mSB), +12.5 +/- 7.1% (nO) and +44.7 +/- 15.9% (CM; P<0.05). deltaP-GC with mSB supplemented with G was +60.9 +/- 30.0% (30 mg; P<0.05) and +156.8 +/- 34.6% (60 mg; P<0.05) at 1 h; deltaP-GC with Pep was 51.0 +/- 31.0% (30 mg equivalent, P<0.05) and +91.1 +/- 9.5% (60 mg equivalent, P<0.05) at 1 h. After 10 days of supplementation with 60 mg/kg bwt G, AP-GC following a further 60 mg/kg bwt G challenge showed a similar increase at 1 h of +154.3 +/- 37.9%; prevalues were unchanged. G and Pep added to CM, increased P-GC by 246.3 +/- 55.3 (+99.2%) and 252.3 +/- 94.2 micromol/l (96.7%) at 1.5 h with concentrations still above prevalues at 8 h (P<0.05). Apart from the CM (with or without supplement), pre P-GC was always regained by 4 h. Plasma NH3 and plasma protein concentrations were unaffected by supplementation with G or Pep.

CONCLUSION

P-GC may be modified by appropriate supplementation with no apparent adverse effects.

POTENTIAL RELEVANCE

Increasing P-GC through appropriate supplementation may be of benefit in the athletically or clinically stressed horse with lowered plasma glutamine concentrations.