Immune and cell modulation by amino acids

Glycine and Melatonin Improve Preimplantation Development of Porcine Oocytes Vitrified at the Germinal Vesicle Stage

Lipid-rich porcine oocytes are extremely sensitive to cryopreservation compared to other low-lipid oocytes. Vitrification has outperformed slowing freezing in oocyte cryopreservation and is expected to improve further by minimizing cellular osmotic and/or oxidative stresses. In this study, we compared the effects of loading porcine cumulus-oocyte complexes with glycine (an organic osmolyte) or glycine plus melatonin (an endogenous antioxidant) during vitrification, thawing and subsequent maturation to mitigate osmotic injuries or osmotic and oxidative damages on the developmental potential of porcine oocytes. Our data demonstrated that glycine treatment significantly increased the vitrification efficiency of porcine oocytes to levels comparable to those observed with glycine plus melatonin treatment. It was manifested as the thawed oocyte viability, oocyte nuclear maturation, contents of reactive oxygen species, translocation of cortical granules and apoptotic occurrence in mature oocytes, levels of ATP and transcripts of glycolytic genes in cumulus cells (markers of oocyte quality), oocyte fertilization and blastocyst development. However, the latter was more likely than the former to increase ATP contents and normal mitochondrial distribution in mature oocytes. Taken together, our results suggest that mitigating osmotic and oxidative stresses induced by vitrification and thawing can further enhance the developmental competency of vitrified porcine oocytes at the germinal vesicle stage.

Free threonine in human breast milk is related to infant intestinal microbiota composition

BACKGROUND

Accumulating evidence indicates that free amino acids (FAA) might be bioactive compounds with potential immunomodulatory capabilities. However, the FAA composition in human milk is still poorly characterized with respect to its correlation to maternal serum levels and its physiological significance for the infant. Studies addressing the relation of human milk FAA to the infants' intestinal microbiota are still missing.

METHODS

As part of a pilot study, maternal serum and breast milk FAA concentrations as well as infant intestinal microbiota (16S rRNA) were determined 2 months after birth. The study cohort consisted of 41 healthy mothers and their term delivered, healthy infants with normal birthweight. The relationship between maternal serum and milk FAA was determined by correlation analyses. Associations between (highly correlated) milk FAA and infant intestinal beta diversity were tested using PERMANOVA, LefSe and multivariate regression models adjusted for common confounders.

RESULTS

Seven breast milk FAA correlated significantly with serum concentrations. One of these, threonine showed a negative association with abundance of members of the class Gammaproteobacteria (R²adj = 17.1%, p = 0.006; β= - 0.441). In addition, on the level of families and genera, threonine explained 23.2% of variation of the relative abundance of Enterobacteriaceae (R²adj; p = 0.001; β = - 0.504) and 11.1% of variability in the abundance of Escherichia/Shigella (R²adj, p = 0.025; β  = - 0.368), when adjusted for confounders.

CONCLUSION

Our study is the first to suggest potential interactions between breast milk FAA and infant gut microbiota composition during early lactation. The results might be indicative of a potential protective role of threonine against members of the Enterobacteriaceae family in breast-fed infants. Still, results are based on correlation analyses and larger cohorts are needed to support the findings and elucidate possible underlying mechanisms to assess the complex interplay between breast milk FAA and infant intestinal microbiota in detail.

Essential amino acid supplementation is associated with reduced serum C-reactive protein levels and improved circulating lymphocytes in post-acute inflamed elderly patients

Background

Persistent systemic inflammation leads to multidistrectual body dysfunctions. Attenuation of inflammation may improve patients’ functional and life prognoses. We hypothesized that essential amino acids (EAAs) given to elderly patients in rehabilitation after acute diseases may be associated with a reduced inflammatory state. Therefore, this retrospective study investigated whether the supplementation of EAAs – modulators of immune competence – was associated with a reduced inflammation rate in elderly patients.

Methods

The medical records of 282 patients admitted to the rehabilitation (rehab) institute after acute index events (surgery or medical diseases) (age: 81.18 ± 8.58 years; females: 67.9%) were analyzed.

Results

46 patients (16.3% of the entire population) had received EAA supplements (S), whereas the remaining 236 patients had not (N-S). Systemic inflammation (I) (serum C-reactive protein (CRP) > 0.5 mg/dL) was present in 67.4% of the I-S group and 57.2% of the I-N-S group. During rehab, the I-S group (but not the I-N-S group) showed a reduction in CRP levels (p = 0.03) and an increase in circulating lymphocytes (p = 0.035), immune cells of the adaptive immune system. C-reactive protein levels remained virtually unchanged in non-inflamed patients who received supplements but increased in non-inflamed patients who did not receive supplements (p = 0.05). Stratified for developed infections, CRP levels reduced in S patients (p = 0.008) but did not in N-S patients.

Conclusion

EAA supplementation was associated with reduced inflammation in both inflamed and infected patients. In addition, EAA supplementation was associated with increased circulating lymphocytes in inflamed patients.

[Glutamine as a component of nutritional and metabolic therapy for surgical patients in ICU]

Glutamine is the most abundant amino acid in the human body that is involved in various metabolic processes. The development of hypermetabolic and hypercatabolic syndrome that accompanies critical conditions of ICU patients is associated with a decrease in the concentration of glutamine, especially in the blood plasma and muscles. This process may last for quite a long time and lead to a number of complications up to a fatal outcome. This review was aimed to analyze clinical studies conducted over the past 20 years that demonstrate the effect of intravenous infusion of glutamine dipeptide as part of balanced parenteral nutrition on the perioperative period: the severity of inflammatory response; the state of the intestinal mucosa; the incidence and severity of complications; mortality; the duration of stay in the ICU and hospital in general, etc. The analysis was performed using systematic reviews and meta-analyses based on randomized double-blind, placebo-controlled trials in different countries selected in the main databases (PubMed, EMBASE, Web of Science, The Cochrane Library, etc.). Most of the reports state that the inclusion of glutamine dipeptide in nutritional and metabolic therapy (NMT) in surgical patients reduces the frequency and severity of infectious complications and mortality, reduces the length of stay in ICU and in hospital in general, improves the biochemical parameters that reflect the condition of patients, and reduces the treatment costs. Thus, the conducted systematic reviews and meta-analyses confirm that the use of the parenteral form of glutamine dipeptide (Dipeptiven 20%) as part of balanced standard parenteral nutrition (PN) is a clinically and pharmacoeconomically justified strategy of NMT in surgical ICU patients.

Invited Review: Maintain or Improve Piglet Gut Health around Weanling: The Fundamental Effects of Dietary Amino Acids

Gut health has significant implications for swine nutrient utilization and overall health. The basic gut morphology and its luminal microbiota play determinant roles for maintaining gut health and functions. Amino acids (AA), a group of essential nutrients for pigs, are not only obligatory for maintaining gut mucosal mass and integrity, but also for supporting the growth of luminal microbiota. This review summarized the up-to-date knowledge concerning the effects of dietary AA supplementation on the gut health of weanling piglets. For instance, threonine, arginine, glutamine, methionine and cysteine are beneficial to gut mucosal immunity and barrier function. Glutamine, arginine, threonine, methionine and cysteine can also assist with relieving the post-weaning stress of young piglets by improving gut immunological functions, antioxidant capacity, and/or anti-inflammatory ability. Glutamine, glutamate, glycine and cysteine can assist to reconstruct the gut structure after its damage and reverse its dysfunction. Furthermore, methionine, lysine, threonine, and glutamate play key roles in affecting bacteria growth in the lumen. Overall, the previous studies with different AA showed both similar and different effects on the gut health, but how to take advantages of all these effects for field application is not clear. It is uncertain whether these AA effects are synergetic or antagonistic. The interactions between the effects of non-nutrient feed additives and the fundamental effects of AA warrant further investigation. Considering the global push to minimize the antibiotics and ZnO usage in swine production, a primary effort at present may be made to explore the specific effects of individual AA, and then the concert effects of multiple AA, on the profile and functions of gut microbiota in young pigs.

Hypervitaminosis A is associated with immunological non-response in HIV-1-infected adults: a case-control study

For people living with HIV, determinants of immunological non-response (INR) to combined antiretroviral therapy (cART) have not been fully elucidated. In a case-control study, we evaluated the influence of the nutritional and antioxidant status in HIV-1 adults whose cART was initiated between January 2001 and December 2013. Cases had persistent CD4 counts < 350/μL vs. > 350/μL for controls, after at least 2 years of cART with persistent viral loads (VL) < 50 copies/mL. Twelve cases and twenty-eight control subjects with the same CD4 count at cART initiation were compared for their nutritional and antioxidant status after age adjustment at dosage assessment. Patients were predominantly male (70%), Caucasian (82%) and at AIDS stage (62%). The median age was 53, and the median CD4 count was 245/mm³ for cases and 630/mm³ for controls after a median time of 7 years on cART. Despite higher energy intakes in cases, anthropometric data was comparable between groups who had similar vitamins B9/B12/C/D/E, zinc, citrulline and glutamine levels. Nine cases (75%) and 8 controls (29%) had hypervitaminosis A (> 2.70 μmol/L) (p = 0.030). Cases had lower erythrocyte resistance when exposed to a controlled free radical attack (p = 0.014). Most cases had hypervitaminosis A and altered antioxidant capacities that could affect immunological response. Wide-scale studies are required, but in the meantime, screening of their vitamin A status must be encouraged in these patients.

Free Amino Acids in Human Milk: A Potential Role for Glutamine and Glutamate in the Protection Against Neonatal Allergies and Infections

Breastfeeding is indicated to support neonatal immune development and to protect against neonatal infections and allergies. Human milk composition is widely studied in relation to these unique abilities, which has led to the identification of various immunomodulating components in human milk, including various bioactive proteins. In addition to proteins, human milk contains free amino acids (FAAs), which have not been well-studied. Of those, the FAAs glutamate and glutamine are by far the most abundant. Levels of these FAAs in human milk sharply increase during the first months of lactation, in contrast to most other FAAs. These unique dynamics are globally consistent, suggesting that their levels in human milk are tightly regulated throughout lactation and, consequently, that they might have specific roles in the developing neonate. Interestingly, free glutamine and glutamate are reported to exhibit immunomodulating capacities, indicating that these FAAs could contribute to neonatal immune development and to the unique protective effects of breastfeeding. This review describes the current understanding of the FAA composition in human milk. Moreover, it provides an overview of the effects of free glutamine and glutamate on immune parameters relevant for allergic sensitization and infections in early life. The data reviewed provide rationale to study the role of free glutamine and glutamate in human milk in the protection against neonatal allergies and infections.

Differences and Effects of Metabolic Fate of Individual Amino Acid Loss in High-Efficiency Hemodialysis and Hemodiafiltration

OBJECTIVE

The objective of the study was to quantify the loss and arterial blood concentration of the three main classes of amino acids (AAs)-nonessential amino acids (NEAAs), essential amino acids (EAAs), and branched-chain amino acids-as resulting from high-efficiency hemodialysis (HED) and hemodiafiltration (HDF). We moreover aimed to identify the different fates and metabolic effects manifested in patients undergoing hemodialysis and the consequences on body composition and influence of nutritional decline into protein energy wasting.

DESIGN AND METHODS

Identical dialysis monitors, membranes, and dialysate/infusate were used to ensure consistency. Ten patients were recruited and randomized to receive treatment with on-line modern HED and HDF. Arterial plasma concentrations of individual AAs were compared in healthy volunteers and patients undergoing hemodialysis, and AA levels outflowing from the dialyzer were evaluated. Baseline AA plasma levels of patients undergoing hemodialysis were compared with findings obtained 1 year later.

RESULTS

A severe loss of AA with HED/HDF was confirmed: a marked loss of total AAs (5 g/session) was detected, corresponding to more than 65% of all AAs. With regard to individual AAs, glutamine displayed a consistent increase (+150%), whereas all other AAs decreased after 12 months of HD/HDF. Only a few AAs, such as proline, cysteine, and histidine maintained normal levels. The most severe metabolic consequences may result from losses of EAAs such as valine, leucine, and histidine and from NEAAs including proline, cysteine, and glutamic acid eliciting the onset of hypercatabolism threatening muscle mass loss.

CONCLUSION

Dialysis losses, together with the effect of chronic uremia, resulted in a reduction of fundamental EAAs and NEAAs, which progressively led our patients after 12 months to a deterioration of lean mass toward sarcopenia. Therefore, the reintroduction of a correctly balanced AA supplementation in patients undergoing HD to prevent or halt decline of hypercatabolism into cachexia is recommended.

An association between glycine and insulin levels is observed in patients with pulmonary tuberculosis and type 2 diabetes

BACKGROUND & AIMS

Adequate nutrition from which amino acids are part gives us protection against infectious or metabolic diseases. In particular, glycine has immunomodulatory properties and is a secretagogue of insulin. However, its absorption rate or plasma levels are impaired in bacterial infection or high glucose levels. The aim of this study was to evaluate the association between glycine and insulin plasma levels in patients with pulmonary tuberculosis (PTB) and type 2 diabetes mellitus (DM2).

METHODS

Plasma levels of insulin and glycine were determined in four groups: 1) patients with PTB; 2) patients with PTB-DM2; 3) household contacts with DM2 (C-DM2), and 4) healthy household contacts (H-C). Likewise, we analyzed the plasma levels of glucose, serine, arginine, lysine, taurine, and glutamic acid.

RESULTS

We observed significant differences in the glycine levels between PTB and PTB-DM2 vs C-DM2 and H-C groups (P < 0.05). We observed also important differences in insulin and glucose levels after comparisons between PTB, PTB-DM2, and C-DM2 vs. H-C groups (P < 0.05). A correlation between glycine and insulin levels in the PTB (r = 0.326) and PTB-DM2 (r = 0.318) groups was found.

CONCLUSION

Our results showed a significant association between glycine and insulin plasma levels in patients with PTB and PTB-DM2, which suggests that the determination of glycine levels could be used as a reference test to evaluate both pathologic conditions. An additional support to the above is that significant changes in the glucose levels in these groups were observed, too.

The relationship between plasma amino acids and circulating albumin and haemoglobin in postabsorptive stroke patients

Background

This retrospective study had two main aims: (1) to document possible correlations between plasma Amino Acids (AAs) and circulating Albumin (Alb) and Haemoglobin (Hb); and (2) to identify which AAs were predictors of Alb and Hb.

Methods

The study considered 125 stroke subjects (ST) (61.6% males; 65.6 +/- 14.9 years) who met the eligibility criteria (absence of co morbidities associated with altered plasma AAs and presence of plasma AAs determined after overnight fasting). Fifteen matched healthy subjects with measured plasma AAs served as controls.

Results

The best correlations of Alb were with tryptophan (Trp) and histidine (His) (r = + 0.53; p < 0.0001), and those of Hb were with histidine (r = +0.47) and Essential AAs (r = +0.47) (both p<0.0001). In multivariate analysis, Trp (p< 0.0001) and His (p = 0.01) were shown to be the best positive predictors of Alb, whereas glutamine (p = 0.006) was the best positive predictor of Hb.

Conclusions

The study shows that the majority of plasma AAs were positively correlated with Alb and Hb. The best predictors of circulating Alb and Hb were the levels of tryptophan and glutamine, respectively.

Roles of Cytosolic Glutamine Synthetases in Arabidopsis Development and Stress Responses

Glutamine (Gln) has as a central role in nitrogen (N) and carbon (C) metabolism. It is synthesized during assimilation of ammonium by cytosolic and plastidial glutamine synthetases (GS; EC 6.1.1.3). Arabidopsis thaliana has five cytosolic GS (GS1) encoding genes designated as GLN1;1-GLN1;5 and one plastidial GS (GS2) gene. In this report that concerns cytosolic GS, we show by analyzing single, double and triple mutants that single genes were dispensable for growth under laboratory conditions. However, loss of two or three GS1 isoforms impacted plant form, function and the capacity to tolerate abiotic stresses. The loss of GLN1;1, GLN1;2 and GLN1;3 resulted in a significant reduction of vegetative growth and seed size. In addition, we infer that GLN1;4 is essential for pollen viability but only in the absence of GLN1;1 and GLN1;3. Transcript profiling revealed that expression of GLN1;1, GLN1;2, GLN1;3 and GLN1;4 was repressed by salinity and cold stresses. Among all single gln1 mutants, growth of gln1;1 seedlings showed an enhanced sensitivity to the GS inhibitor phosphinothricin (PPT), as well as to cold and salinity treatments, suggesting a non-redundant role for GLN1;1. Furthermore, the increased sensitivity of gln1;1 mutants to methyl viologen was associated with an accelerated accumulation of reactive oxygen species (ROS) in the thylakoid of chloroplasts. Our data demonstrate, for the first time, an involvement of the cytosolic GS1 in modulating ROS homeostasis in chloroplasts. Collectively, the current study establishes a link between cytosolic Gln production and plant development, ROS production and stress tolerance.

Physiological Effects of Dietary Amino Acids on Gut Health and Functions of Swine

Gut health has significant implications for swine overall health status and nutrient utilization, due to its various functions including digestion and absorption of nutrients, secretion of mucins and immunoglobulins, and selective barrier protection against harmful antigens and pathogens. Both the basic anatomical structure of the gut (such as epithelial cells) and its luminal microbiota play important roles for maintaining gut health and functions. The interactions between epithelial cells and luminal microbiota have significant impact on host nutrition and health through the metabolism of dietary components. Amino acids, which are major nutrients for pigs, are not only obligatory for maintaining the intestinal mucosal mass and integrity, but also for supporting the growth of microorganisms in the gut. Dietary amino acids are the major fuel of the small intestinal mucosa. Particularly, glutamate, glutamine, and aspartate are the major oxidative fuel of the intestine. Emerging evidence shows that arginine activates the mTOR signaling pathway in the small intestine. Utilization of glycine by the small intestinal mucosa to synthesize glutathione is a very important physiological pathway, and the role of glycine as a powerful cytoprotectant has also been recognized. The major end products of methionine and cysteine metabolism are glutathione, homocysteine and taurine, which play important roles in the intestinal immune and anti-oxidative responses. Threonine is highly utilized by the gut and is particularly important for mucin synthesis and maintenance of gut barrier integrity. Moreover, either a deficiency or an excess of dietary threonine can reduce the synthesis of intestinal mucosal proteins and mucins in young pigs. Various new functions of amino acids on gut health and functions have been discovered in recent years. Thus, this review is to provide some up-to-date knowledge for industry application of dietary amino acids in order to enhance swine gut health and functions, and also it is to provide a comprehensive reference for further scientific research in this regard.

Muscle wasting in the presence of disease, why is it so variable?

Skeletal muscle wasting is a common clinical feature of many chronic diseases and also occurs in response to single acute events. The accompanying loss of strength can lead to significant disability, increased care needs and have profound negative effects on quality of life. As muscle is the most abundant source of amino acids in the body, it appears to function as a buffer for fuel and substrates that can be used to repair damage elsewhere and to feed the immune system. In essence, the fundamentals of muscle wasting are simple: less muscle is made than is broken down. However, although well-described mechanisms modulate muscle protein turnover, significant individual differences in the amount of muscle lost in the presence of a given severity of disease complicate the understanding of underlying mechanisms and suggest that individuals have different sensitivities to signals for muscle loss. Furthermore, the rate at which muscle protein is turned over under normal conditions means that clinically significant muscle loss can occur with changes in the rate of protein synthesis and/or breakdown that are too small to be measurable. Consequently, the changes in expression of factors regulating muscle turnover required to cause a decline in muscle mass are small and, except in cases of rapid wasting, there is no consistent pattern of change in the expression of factors that regulate muscle mass. MicroRNAs are fine tuners of cell phenotype and are therefore ideally suited to cause the subtle changes in proteome required to tilt the balance between synthesis and degradation in a way that causes clinically significant wasting. Herein we present a model in which muscle loss as a consequence of disease in non-muscle tissue is modulated by a set of microRNAs, the muscle expression of which is associated with severity of disease in the non-muscle tissue. These microRNAs alter fundamental biological processes including the synthesis of ribosomes and mitochondria leading to reduced protein synthesis and increased protein breakdown, thereby freeing amino acids from the muscle. We argue that the variability in muscle loss observed in the human population arises from at least two sources. The first is from pre-existing or disease-induced variation in the expression of microRNAs controlling the sensitivity of muscle to the atrophic signal and the second is from the expression of microRNAs from imprinted loci (i.e. only expressed from the maternally or paternally inherited allele) and may control the rate of myonuclear recruitment. In the absence of disease, these factors do not correlate with muscle mass, since there is no challenge to the established balance. However, in the presence of such a challenge, these microRNAs determine the rate of decline for a given disease severity. Together these mechanisms provide novel insight into the loss of muscle mass and its variation in the human population. The involvement of imprinted loci also suggests that genes that regulate early development also contribute to the ability of individuals to resist muscle loss in response to disease.

l-glutamine in vitro supplementation enhances Nile tilapia Oreochromis niloticus (Linnaeus, 1758) leukocyte function

Under appropriate conditions, glutamine (Gln) is an essential nutrient for immunological responses, acting as a metabolic substrate for proliferation of enterocytes and lymphocytes, and having positive effects on the function of stimulated immune cells. Thus, specific components of both innate and adaptive immune systems of Nile tilapia were evaluated after supplementing Gln to cell culture media. Primary cell cultures of kidney leukocytes were used for respiratory burst and phagocytic activity assessment. The ability of macrophages to kill Streptococcus iniae also was evaluated. Additionally, a proliferation assay was conducted with peripheral blood lymphocytes (PBL) exposed to non-specific mitogens. Results showed that macrophage phagocytosis, anion superoxide production, and bactericidal capacity were significantly (P < 0.05) enhanced by Gln supplementation to the culture media. The proliferation of lymphocytes upon mitogenic exposure also was significantly (P < 0.05) enhanced by Gln supplementation to the media. Our results suggest that in vitro, different levels of Gln were necessary for optimal immunological responses of leukocytes and lymphocytes. As such, Gln supplementation was able to enhance and modulate both innate and adaptive responses of Nile tilapia leukocytes, highlighting its potential application as an immunonutrient.

Once small always small? To what extent morphometric characteristics and post-weaning starter regime affect pig lifetime growth performance

Background

The aim of this study was to determine the effect of piglet morphometric characteristics and starter regime on postnatal growth. Some piglets born light are able to grow faster than others, and identifying which piglets are more at risk to remain light and at which stages of growth is essential. A nutrient enriched starter regime may allow lightweight pigs to improve their post-weaning growth. A total 1487 newly born piglets from 137 litters originating from 8 consecutive farrowing batches were followed from birth (BiW) to weaning (WW, d28) and finishing (d99). At birth morphometric measurements were taken, including body mass index (BMI), ponderal index (PI) and BiW:cranial circumferences (BiW:CC). At weaning pigs were randomly allocated to one of two experimental regimes: either a nutrient enriched regime with a 20% higher essential amino acids (EAA): energy ratio (HIGH) or a standard regime (CTRL). Piglets were retrospectively allocated to 4 different weight classes (C) using percentiles at birth, weaning and finishing, with C1 representing the lightest and C4 the heaviest class. A series of novel statistical models were used to determine which factors were able to predict performance.

Results

For BiW C1 piglets, BMI (P = 0.003) and BiW relative to birth litter (P = 0.026) were positively associated with pre-weaning performance, whereas BiW:CC (P = 0.011) and WW (P = 0.001) were positively associated with post-weaning growth. Post-weaning the best predictors of piglets weaned light (WW C1) were PI (P = 0.037), BiW:CC (P < 0.001) and WW (P < 0.001). Starter regime did not influence (P > 0.05) post-weaning performance.

Conclusion

Our results show that not all light pigs are the same and that their performance is under the influence of body shape rather than BiW. Therefore, pig producers should discriminate between light pigs based on birth characteristics to improve the effectiveness of intervention strategies at the different stages of growth. Irrespective of weight class piglets did not benefit from the EAA enriched regime applied.

Electronic supplementary material

The online version of this article (10.1186/s40813-018-0098-1) contains supplementary material, which is available to authorized users.

Effects of dietary spermine supplementation on cell cycle, apoptosis, and amino acid transporters of the thymus and spleen in piglets

Objective

This study investigated whether spermine supplementation could regulate cell cycle, apoptosis, and amino acid transporter-related genes expression in the thymus and spleen of early weaned piglets.

Methods

Eighty female piglets were randomly distributed to receive adequate nutrients supplemented with spermine (0.4 mmol/kg body weight/24 h) or to be provided with restricted nourishment supplemented with normal saline for 7 h or 3, 6, or 9 d in pairs.

Results

Regardless of administration time, spermine supplementation significantly up-regulated cyclin A2 gene expression but down-regulated p21 and cyclin D3 mRNA levels in the thymus and spleen and reduced cyclin E2 gene expression in the thymus of piglets (p< 0.05). Irrespective of the treatment period, the reduced Bax and caspase-3 gene expressions and improved Bcl-2 mRNA level were observed in the thymus and spleen of spermine-administrated piglets (p<0.05). Regardless of supplementation time, spermine intake significantly enhanced the expressions of amino acid transporter-related genes (SLC1A1, SLC1A5, SLC7A1, SLC7A7, and SLC15A1) in both thymus and spleen, as well as SLC7A9 in the spleen of piglets (p<0.05). In addition, extended spermine administration also markedly promoted cell proliferation, depressed apoptosis and modulated amino acid transport (p< 0.05), and such effects were the greatest during prolonged spermine supplementation (6 d) compared to the other time periods (p<0.05).

Conclusion

Spermine supplementation may regulate cell cycle during the G1/S phase, suppress apoptosis and modulate amino acid transport. A period of 6 d of spermine supplementation is required to produce the optimal effects on nutritional implications.

Interaction Between 2 Nutraceutical Treatments and Host Immune Status in the Pediatric Critical Illness Stress-Induced Immune Suppression Comparative Effectiveness Trial

BACKGROUND AND AIMS

The pediatric Critical Illness Stress-induced Immune Suppression (CRISIS) trial compared the effectiveness of 2 nutraceutical supplementation strategies and found no difference in the development of nosocomial infection and sepsis in the overall population. We performed an exploratory post hoc analysis of interaction between nutraceutical treatments and host immune status related to the development of nosocomial infection/sepsis.

METHODS

Children from the CRISIS trial were analyzed according to 3 admission immune status categories marked by decreasing immune competence: immune competent without lymphopenia, immune competent with lymphopenia, and previously immunocompromised. The comparative effectiveness of the 2 treatments was analyzed for interaction with immune status category.

RESULTS

There were 134 immune-competent children without lymphopenia, 79 previously immune-competent children with lymphopenia, and 27 immunocompromised children who received 1 of the 2 treatments. A significant interaction was found between treatment arms and immune status on the time to development of nosocomial infection and sepsis ( P < .05) and on the rate of nosocomial infection and sepsis per 100 patient days ( P < .05). Whey protein treatment protected immune-competent patients without lymphopenia from infection and sepsis, both nutraceutical strategies were equivalent in immune-competent patients with lymphopenia, and zinc, selenium, glutamine, and metoclopramide treatment protected immunocompromised patients from infection and sepsis.

CONCLUSIONS

The science of immune nutrition is more complex than previously thought. Future trial design should consider immune status at the time of trial entry because differential effects of nutraceuticals may be related to this patient characteristic.

[The Metabolic Optimized Fast Track Concept: preoperative preparation for abdominal surgery]

In recent years the protocols of Enhanced Recovery After Surgery (E.R.A.S.) have been introduced into clinical practice and actively used. The goal of E.R.A.S. is to increase recovery, decrease complications and reduce length of stay after surgery through optimization of perioperative management. One of the key elements of E.R.A.S. is Metabolic Optimized Fast Track Concept (MOFA). It is aimed at the reduction of the period of preoperative fasting and at the activation of glucose transport inside the cell. It involves the administration of combined carbohydrate-protein-glutamine drinks which results into decreased insulin resistance in the early postoperative period. The implementation of MOFA within the structure of perioperative nutrition and metabolic support in abdominal surgery may actually be beneficial by reducing postoperative complications, length of hospital stay and mortality rate.

Nutrition and Immune System in Children with Simple Obesity

The purpose of this study was to evaluate dietary factors in nutrition influencing the immune system of children and teenagers suffering from simple obesity. The study involved 100 children and teenagers aged 7-18 with simple obesity. Nutritional data were obtained from 3-day food records. The consumed nutrients, including immunomodulators and immunostimulants, were estimated based on the nutrition interview. The results were compared with the nutritional norms. On average, the proportion of n-6:n-3 fatty acids equalled 10:1. Among the amino acids, the highest intake values in the diet were observed for glutamine (13,694.6 mg/day). The study demonstrates inadequate intake levels of iron (73% of recommended dietary allowance, RDA), vitamin C (65% of RDA), and vitamin D (11% of RDA) taking into account the median values for the entire study group. The median daily intake of other nutrients exceeded the RDA values. The diets of the participants in this study were not properly balanced with respect to immunomodulators, which may contribute to the occurrence of immunological disorders and immunodeficiency in this group of patients.

The Hip Functional Retrieval after Elective Surgery May Be Enhanced by Supplemented Essential Amino Acids

It is not known whether postsurgery systemic inflammation and plasma amino acid abnormalities are still present during rehabilitation of individuals after elective hip arthroplasty (EHA). Sixty subjects (36 females; age 66.58 ± 8.37 years) were randomized to receive 14-day oral EAAs (8 g/day) or a placebo (maltodextrin). At admission to and discharge from the rehabilitation center, serum C-reactive protein (CRP) and venous plasma amino acid concentrations were determined. Post-EHA hip function was evaluated by Harris hip score (HHS) test. Ten matched healthy subjects served as controls. At baseline, all patients had high CRP levels, considerable reduction in several amino acids, and severely reduced hip function (HHS 40.78 ± 2.70 scores). After treatment, inflammation decreased both in the EAA group and in the placebo group. Only EAA patients significantly improved their levels of glycine, alanine, tyrosine, and total amino acids. In addition, they enhanced the rate of hip function recovery (HHS) (from baseline 41.8 ± 1.15 to 76.37 ± 6.6 versus baseline 39.78 ± 4.89 to 70.0 ± 7.1 in placebo one; p = 0.006). The study documents the persistence of inflammation and plasma amino acid abnormalities in post-EHA rehabilitation phase. EAAs enhance hip function retrieval and improve plasma amino acid abnormalities.

Glutamine metabolism in advanced age

Glutamine, reviewed extensively in the last century, is a key substrate for the splanchnic bed in the whole body and is a nutrient of particular interest in gastrointestinal research. A marked decrease in the plasma glutamine concentration has recently been observed in neonates and adults during acute illness and stress. Although some studies in newborns have shown parenteral and enteral supplementation with glutamine to be of benefit (by decreasing proteolysis and activating the immune system), clinical trials have not demonstrated prolonged advantages such as reductions in mortality or risk of infections in adults. In addition, glutamine is not able to combat the muscle wasting associated with disease or age-related sarcopenia. Oral glutamine supplementation initiated before advanced age in rats increases gut mass and improves the villus height of mucosa, thereby preventing the gut atrophy encountered in advanced age. Enterocytes from very old rats continuously metabolize glutamine into citrulline, which allowed, for the first time, the use of citrulline as a noninvasive marker of intestinal atrophy induced by advanced age.

Correlation of deglutition in subacute ischemic stroke patients with peripheral blood adaptive immunity: Essential amino acid improvement

We aimed to document in stroke patients peripheral blood immune cell profiles, their relations with neuro-functional tests, and any possible influence of supplemented essential amino acids (EAAs) may have on both the immune system and the relationship of the latter with neuro-function.Forty-two dysphagic stroke patients (27 men; 71±9 years) underwent bio-humoral measurements, neuro-functional tests, including Functional Independence Measure (FIM) and Dysphagia Outcome and Severity Scale (DOSS), and were randomized to receive EAAs 8 g/d (EAA group) or isocaloric maltodextrin (placebo group).At discharge all measurements were repeated 38±1 days after randomization.At admission, total white cell (TWC), neutrophil (N), and lymphocyte (Lymph) counts were normal and the N/Lymph ratio was higher than normal values (<3.0). At discharge, both TWC and N decreased while Lymph increased significantly. As a result, the N/Lymph ratio significantly decreased (P <0.001) returning to normal levels. Absolute Lymph counts and Lymph % TWC correlated positively with DOSS (r = +0.235, P = 0.04 and r = +0.224, P = 0.05, respectively), negatively with C-reactive protein natural logarithm (ln CRP) (P = 0.02 and P = 0.0001, respectively), which is an inflammation marker. N correlated positively with ln CRP (P = 0.001) and had a slight negative association with FIM (P = 0.07). The N/Lymph ratio was inversely related to FIM (r = -0.262, P = 0.02) and DOSS (r = -0.279, P = 0.01). Finally, FIM correlated with DOSS (r = +0.35, P = 0.05).For the regression analysis, the overtime changes of Lymph % TWC correlated significantly with DOSS (P = 0.01). There was a positive correlation between Lymph % TWC and DOSS for the entire stroke population (P = 0.015). While this correlation was not important for the placebo group (P = 0.27), it was significant in the EAA subgroup (P = 0.018).In the sub-acute stroke stage, there may be slight alterations of peripheral blood immune cells. Lymph cells are associated with improved neuro-function tests with evidence that this association is enhanced by supplementing EAAs.

The complex liaison between cachexia and tumor burden (Review)

Cachexia is a wasting syndrome that afflicts end-stage cancer patients. Whereas a consensus statement for a definition of cachexia recently has been accomplished, a useful measurement for this condition at present is lacking. The aim of the present review is to discuss the advantage of introducing the measurement of tumor burden for a better overall evaluation of cachexia. Our suggestion ensues from a somewhat novel perspective in the field of infectious disease research where a careful measurement of the pathogen load, between i.e. different host genotypes, leads to the definition of the concept of tolerance to the infectious insult. Indeed tolerance concurs, together the more classical resistance, in maintaining the host reproductive fitness or health state. Noticeably a similar reasoning may apply to tumor biology as well. Whereas the extent of cachexia increases with tumor burden, the relationship between these two correlates of tumor progression fluctuates in a broad range. We have selected from the literature studies in the rodent model where significant variation in the course of the wasting illness during cancer was observed and quantitatively assessed comparing experimental groups marked by different genotype, drug treatment, diet or gender. These studies may be further classified in two categories: the former where the experimental condition associated to milder cachexia is accompanied to a lesser tumor burden, the latter where the inhibition of cachexia results disentangled from the tumor burden, that is the whole number of cancer cells results unchanged or even, paradoxically, is increased. In addition we survey, even in the context of human malignancy, the significance and feasibility of plotting quantitative estimates of cachexia against the whole tumor burden. Ultimately, the principal endeavor of introducing the measurement of tumor burden, in both experimental and clinical oncology, may be to achieve a better assessment of the inter-individual variation in the host vulnerability to cancer cachexia.

In Ovo Administration of Silver Nanoparticles and/or Amino Acids Influence Metabolism and Immune Gene Expression in Chicken Embryos

Due to their physicochemical and biological properties, silver nanoparticles (NanoAg) have a wide range of applications. In the present study, their roles as a carrier of nutrients and an immunomodulator were tested in chicken embryos. Cysteine (Cys)+NanoAg injected embryos had smaller livers but heavier breasts on the 19th day of embryogenesis. Cys injected embryos had lower oxygen consumption compared to threonine (Thr) or NanoAg injected embryos. The energy expenditure in Thr+NanoAg, or NanoAg injected embryos was higher than Cys or Cys+NanoAg but was not different from uninjected control embryos. Relative expression of the hepatic insulin-like growth factor-I (IGF-I) gene was higher in Cys or NanoAg injected embryos after lipopolysaccharide (LPS) induction. The gene expression of hepatic tumour necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6) did not differ among amino acids, NanoAg and uninjected controls in the non-LPS groups, but increased by many folds in the LPS treated NanoAg, Cys and Cys+NanoAg groups. In LPS treated spleens, TNF-α expression was also up-regulated by NanoAg, amino acids and their combinations, but interleukin-10 (IL-10) expression was down-regulated in Thr, Cys or Thr+NanoAg injected embryos. Toll like receptor-2 (TLR2) expression did not differ in NanoAg or amino acids injected embryos; however, toll like receptor-4 (TLR4) expression was higher in all treated embryos, except for Cys+NanoAg, than in uninjected control embryos. We concluded that NanoAg either alone or in combination with amino acids did not affect embryonic growth but improved immunocompetence, indicating that NanoAg and amino acid complexes can act as potential agents for the enhancement of innate and adaptive immunity in chicken.

Different Effects of Sheep- and Duck-Meat Supplemented Diets on Serum Cytokine Levels of Rats

This study aimed to explore the mechanism underlying the different effects of diet supplemented with sheep- or duck-meat on serum cytokines of rats.

METHODS

Male Sprague-Dawley rats were randomly divided into three groups fed on sheep meat, duck meat, or soybean, respectively. The profiles of amino acids and fatty acids of the three diets were examined, and the levels of serum cytokines in rats, including interleukin-1β (IL-1β), IL-2, IL-4, IL-6, IL-10 and tumor necrosis factor-α (TNF-α), were detected 30 d after feeding, using radioimmunoassay. The contents of methionine and glycine in the sheep-meat and duck-meat diets were significantly higher than those in the soybean diet. The content of saturated fatty acids in the sheep-meat diet and duck-meat diet was higher than that in soybeans, while the polyunsaturated fatty acids (PUFAs) in the duck-meat diet were highest and those in the sheep-meat diet were lowest. Serum levels of IL-2 and IL-10 in the rats of the sheep-meat and duck-meat groups were significantly higher than those in the rats of the soybean group (p<0.05). IL-10 and TNF-α in the rats of the sheep-meat group were higher than those in the duck-meat group. But the levels of IL-1β and IL-6 were not significantly different among the three groups. Additionally, there were positive correlations between glycine and IL-1β as well as glycine and IL-2, while negative correlation existed between C18:2 and TNF-α. Methionine, glycine and PUFAs in a diet supplemented with sheep- or duck-meat might influence the levels of serum cytokines in rats, suggesting the potential regulatory mechanism of amino acids and fatty acids from diet in immune responses.

Protein energy malnutrition increases arginase activity in monocytes and macrophages

Background

Protein energy malnutrition is commonly associated with immune dysfunctions and is a major factor in susceptibility to infectious diseases.

Methods

In this study, we evaluated the impact of protein energy malnutrition on the capacity of monocytes and macrophages to upregulate arginase, an enzyme associated with immunosuppression and increased pathogen replication.

Results

Our results show that monocytes and macrophages are significantly increased in the bone marrow and blood of mice fed on a protein low diet. No alteration in the capacity of bone marrow derived macrophages isolated from malnourished mice to phagocytose particles, to produce the microbicidal molecule nitric oxide and to kill intracellular Leishmania parasites was detected. However, macrophages and monocytes from malnourished mice express significantly more arginase both in vitro and in vivo. Using an experimental model of visceral leishmaniasis, we show that following protein energy malnutrition, the increased parasite burden measured in the spleen of these mice coincided with increased arginase activity and that macrophages provide a more permissive environment for parasite growth.

Conclusions

Taken together, these results identify a novel mechanism in protein energy malnutrition that might contributes to increased susceptibility to infectious diseases by upregulating arginase activity in myeloid cells.

Electronic supplementary material

The online version of this article (doi:10.1186/1743-7075-11-51) contains supplementary material, which is available to authorized users.

Protective effects of nutritional supplementation with arginine and glutamine on the penis of rats submitted to pelvic radiation

Radiotherapy is widely used to treat pelvic malignancies, but normal tissues near the target tumour are often affected. Our aims were thus to determine whether the structural organization of the rat penis is altered by radiation, and whether supplementation with L-arginine (ARG) or L-glutamine (GLN) would have protective effects against these alterations. Groups of rats were treated with: no intervention (CONTR); pelvic radiation, followed by sacrifice 7 (RAD7) or 15 (RAD15) days later; and pelvic radiation, daily supplementation with ARG or GLN, followed by sacrifice 7 (RAD7+ARG, RAD7+GLN) or 15 (RAD15+ARG, RAD15+GLN) days after radiation. Structural components in the corpus cavernosum (CC), tunica albuginea of the corpus spongiosum (TACS) and urethral epithelium (UE) were analysed using stereological and immunohistochemical methods. The results showed that in the CC, connective tissue was increased by 18% in RAD15 (p < 0.04), but this change was partially prevented in RAD15+GLN (p < 0.05) and RAD15+ARG (p < 0.04). The fibrous matrix of the CC trabeculae stained evenly for collagen type I. In RAD15, the intensity of the labelling was increased, whereas in RAD15+GLN and RAD15+ARG the staining was similar to that of CONTR. No staining changes were seen in the groups that were sacrificed 7 days after radiation. Cavernosal elastic fibre content in RAD15 was increased by 61% (p < 0.004), and this was prevented in RAD15+ARG (p < 0.004) but not in RAD15+GLN. In TACS, the amino acids protected (p < 0.02) against the radiation-induced 92% increase in elastic fibre content, but only in RAD15. Cell density in the UE, as well as UE thickness, were reduced by 30% in RAD15 (p < 0.004), and there were protective effects of both amino acids. In conclusion, radiation-induced alterations in penile structures tend to be more pronounced 15 days after radiation session. Both ARG and GLN have protective effects against these changes, with the former being slightly more effective.

Amino acid concentrations in critically ill children following cardiac surgery*

OBJECTIVE

Guidelines for administering amino acids to critically ill children are largely based on uncontrolled observational studies and expert opinion, without support from rigorous outcome studies. Also, data on circulating amino acid concentrations during critical illness are scarce. We thoroughly studied the time profiles of circulating amino acid concentrations in critically ill children who received standard nutritional care according to international guidelines.

DESIGN

This is a subanalysis of pediatric critically ill patients included in a large (n = 700) randomized controlled study on intensive insulin therapy.

SETTING

The study was conducted at a university hospital PICU.

PATIENTS

We studied 100 patients in PICU for at least 3 days following cardiac surgery.

INTERVENTIONS

Patients were assigned to intensive insulin therapy targeting normal-for-age fasting blood glucose concentrations or insulin infusion only to prevent excessive hyperglycemia.

MEASUREMENTS AND MAIN RESULTS

Plasma amino acid concentrations were measured at admission, day 3, and day 7 in PICU. At admission, the concentrations of most amino acids were comparable to those reported for healthy children. Total amino acid concentrations remained stable during ICU stay, but individual amino acids showed different time profiles with eight of them showing an increase and five a decrease. Nonsurviving children had higher total amino acid concentrations and individual amino acids compared with survivors at admission and/or during ICU stay. Intensive insulin therapy lowered the concentrations of total amino acids and several individual amino acids. Neonates showed somewhat different amino acid profiles with rather increased concentrations from baseline with time in ICU for total amino acids and several individual amino acids as compared with older infants and children.

CONCLUSIONS

Circulating amino acid concentrations in critically ill children after cardiac surgery differ according to survival status, blood glucose control with intensive insulin therapy, and age.

Neurorestorative targets of dietary long-chain omega-3 fatty acids in neurological injury

Long-chain omega-3 polyunsaturated fatty acids (LC-O3PUFAs) exhibit therapeutic potential for the treatment and prevention of the neurological deficits associated with spinal cord injury (SCI). However, the mechanisms implicated in these protective responses remain unclear. The objective of the present functional metabolomics study was to identify and define the dominant metabolic pathways targeted by dietary LC-O3PUFAs. Sprague-Dawley rats were fed rodent purified chows containing menhaden fish oil-derived LC-O3PUFAs for 8 weeks before being subjected to sham or spinal cord contusion surgeries. We show, through untargeted metabolomics, that dietary LC-O3PUFAs regulate important biochemical signatures associated with amino acid metabolism and free radical scavenging in both the injured and sham-operated spinal cord. Of particular significance, the spinal cord metabolome of animals fed with LC-O3PUFAs exhibited reduced glucose levels (-48 %) and polar uncharged/hydrophobic amino acids (less than -20 %) while showing significant increases in the levels of antioxidant/anti-inflammatory amino acids and peptides metabolites, including β-alanine (+24 %), carnosine (+33 %), homocarnosine (+27 %), kynurenine (+88 %), when compared to animals receiving control diets (p < 0.05). Further, we found that dietary LC-O3PUFAs impacted the levels of neurotransmitters and the mitochondrial metabolism, as evidenced by significant increases in the levels of N-acetylglutamate (+43 %) and acetyl CoA levels (+27 %), respectively. Interestingly, this dietary intervention resulted in a global correction of the pro-oxidant metabolic profile that characterized the SCI-mediated sensorimotor dysfunction. In summary, the significant benefits of metabolic homeostasis and increased antioxidant defenses unlock important neurorestorative pathways of dietary LC-O3PUFAs against SCI.

A metabolic link to skeletal muscle wasting and regeneration

Due to its essential role in movement, insulating the internal organs, generating heat to maintain core body temperature, and acting as a major energy storage depot, any impairment to skeletal muscle structure and function may lead to an increase in both morbidity and mortality. In the context of skeletal muscle, altered metabolism is directly associated with numerous pathologies and disorders, including diabetes, and obesity, while many skeletal muscle pathologies have secondary changes in metabolism, including cancer cachexia, sarcopenia and the muscular dystrophies. Furthermore, the importance of cellular metabolism in the regulation of skeletal muscle stem cells is beginning to receive significant attention. Thus, it is clear that skeletal muscle metabolism is intricately linked to the regulation of skeletal muscle mass and regeneration. The aim of this review is to discuss some of the recent findings linking a change in metabolism to changes in skeletal muscle mass, as well as describing some of the recent studies in developmental, cancer and stem-cell biology that have identified a role for cellular metabolism in the regulation of stem cell function, a process termed “metabolic reprogramming.”

Efficacy of glutamine in the prevention of oral mucositis and acute radiation-induced esophagitis: a retrospective study

Glutamine is a nutraceutic with antioxidant and immune functions that can protect from adverse effects associated with radiation therapy (RT). The aim of this study was to test whether oral glutamine prevents oral mucositis (OM) or acute radiation-induced esophagitis (ARIE) and favors nutritional status. This retrospective, cohort study included patients treated with RT for cancer on head and neck (HN) or chest areas during the 2008-2010 period. Data on glutamine treatment (initiated before RT, during RT, or no glutamine), appearance of mucositis (according to World Health Organization criteria), weight loss (WL) during RT, moderate [body mass index (BMI) <20.5 kg/m(2) or WL > 5%) or severe (BMI < 18.5 kg/m(2) or WL > 10%) malnutrition, and nutritional support were collected. Quantitative data were compared using Student's t-test and analysis of variance, and qualitative data using the chi-square test. The risk difference was calculated with its 95% confidence interval (95% CI). The sample included 117 patients. Overall, glutamine was associated with a significant reduction of mucositis, WL, and enteral nutrition. The risk difference for developing OM in patients receiving glutamine when compared with controls was -9.0% (95% CI = -18.0% to -1.0%), and for ARIE it was -14.0% (95% CI = -26.0% to -1.0%). More of the patients not receiving glutamine developed severe malnutrition when compared with those receiving this supplement, but there were no differences in other outcomes such as interruption of RT, hospitalization, use of opioid analgesics, or death during RT. Glutamine may have a protective effect during RT, reducing the risk and severity of OM and ARIE, preventing weight loss, and reducing the need for nutritional support. Prospective trials are required.

Dietary protein excess during neonatal life alters colonic microbiota and mucosal response to inflammatory mediators later in life in female pigs

The interplay between the colonic microbiota and gut epithelial and immune cells during the neonatal period, which establishes the structure of the microbiota and programs mucosal immunity, is affected by the diet. We hypothesized that protein-enriched milk formula would disturb this interplay through greater flux of protein entering the colon, with consequences later in life. Piglets were fed from postnatal day (PND) 2 to 28 either a normal-protein formula (NP; 51 g protein/L) or high-protein formula (HP; 77 g protein/L) and weaned at PND28, when they received standard diets until PND160. HP feeding transiently increased the quantity of protein entering the colon (PND7) but did not change the microbiota composition at PND28, except for a higher production of branched-chain fatty acids (BCFAs) in an in vitro fermentation test (P < 0.05). HP piglets had greater colonic mucosa densities of cluster of differentiation (CD) 3(+) and CD172(+) cells and lower Il-1β and Tnfα mRNA levels at PND28 (P < 0.05). Later in life (PND160), HP females, but not males, had a higher increase in colonic permeability after ex vivo oxidative stress and higher cytokine secretion in response to lipopolysaccharide in colonic explant cultures than NP females (P < 0.05). HP females also had lower colonic amounts of F. prausnitzii and BCFAs (P < 0.05). BCFAs displayed a dose-dependent protection against inflammation-induced alteration of barrier function in Caco-2 cells (P < 0.05). In conclusion, protein-enriched formula had little impact on colonic microbiota, but it modified colonic immune cell development and had a long-term effect on adult colonic mucosa sensitivity to inflammatory insults, probably through microbiotal and hormonal factors.

Glycine administration attenuates skeletal muscle wasting in a mouse model of cancer cachexia

BACKGROUND AND AIMS

The non-essential amino acid, glycine, is often considered biologically neutral, but some studies indicate that it could be an effective anti-inflammatory agent. Since inflammation is central to the development of cancer cachexia, glycine supplementation represents a simple, safe and promising treatment. We tested the hypothesis that glycine supplementation reduces skeletal muscle inflammation and preserves muscle mass in tumor-bearing mice.

METHODS

To induce cachexia, CD2F1 mice received a subcutaneous injection of PBS (control, n = 12) or C26 tumor cells (n = 32) in accordance with the protocols developed by Murphy et al. [Murphy KT, Chee A, Trieu J, Naim T, Lynch GS. Importance of functional and metabolic impairments in the characterization of the C-26 murine model of cancer cachexia. Dis Models Mech 2012;5(4):533-545.]. Subcutaneous injections of glycine (n = 16) or PBS (n = 16) were administered daily for 21 days and at the conclusion of treatment, selected muscles, tumor and adipose tissue were collected and prepared for Real-Time RT-PCR or western blot analysis.

RESULTS

Glycine attenuated the loss of fat and muscle mass, blunted increases in markers of inflammation (F4/80, P = 0.01 & IL-6 mRNA, P = 0.01) and atrophic signaling (MuRF, P = 0.047; atrogin-1, P = 0.04; LC3B, P = 0.06 and; BNIP3, P = 0.10) and tended to attenuate the loss of body mass (P = 0.07), muscle function (P = 0.06), and oxidative stress (GSSG/GSH, P = 0.06 and DHE, P = 0.07) seen in tumor-bearing mice. Preliminary studies that compared the effect of glycine administration with isonitrogenous doses of alanine or citrulline showed that the observed protective effect was specific to glycine.

CONCLUSIONS

Glycine protects skeletal muscle from cancer-induced wasting and loss of function, reduces the oxidative and inflammatory burden, and reduces the expression of genes associated with muscle protein breakdown in cancer cachexia. Importantly, these effects were glycine specific.

Modulation of Human Colostrum Phagocyte Activity by the Glycine-Adsorbed Polyethylene Glycol Microspheres

Colostrum is a secretion that contains immunologically active components, including immunocompetent cells and glycine, which has anti-inflammatory, immunomodulatory, and cytoprotective effects. The aim of this study was to evaluate the adsorption of glycine onto polyethylene glycol (PEG) microspheres and to verify the immunomodulatory effect of this nanomaterial on human colostrum phagocytes. The PEG microspheres were evaluated by fluorescence microscopy. The effects of PEG microspheres with adsorbed glycine on viability, superoxide release, phagocytosis, microbicidal activity, and intracellular calcium release of mononuclear (MN) and polymorphonuclear (PMN) colostrum phagocytes were determined. Fluorescence microscopy analyses revealed that glycine was able to be adsorbed to the PEG microspheres. The PMN phagocytes exposed to glycine-PEG microspheres showed the highest superoxide levels. The phagocytes (both MN and PMN) displayed increased microbicidal activity and intracellular calcium release in the presence of PEG microspheres with adsorbed glycine. These data suggest that the adsorption of PEG microspheres with adsorbed glycine was able to stimulate the colostrum phagocytes. This material may represent a possible alternative therapy for future clinical applications on patients with gastrointestinal infections.

The role of the enteral route and the composition of feeds in the nutritional support of malnourished surgical patients

In surgical patients, malnutrition is an important risk factor for post-operative complications. In undernourished patients undergoing major gastrointestinal procedures, preoperative enteral nutrition (EN) should be preferred whenever feasible. It may be given either orally or by feeding tubes, depending on patient compliance. Early oral intake after surgery should be encouraged, but if an insufficient postoperative oral intake is anticipated, tube feeding should be initiated as soon as possible. The use of immunomodulating formulas offers significant advantages when compared to standard feeds and the positive results on postoperative complications seem independent from the baseline nutritional status. In malnourished patients, the optimal timing and dose of immunonutrition is unclear, but consistent data suggest that they should be treated peri-operatively for at least two weeks.

Supplementation of essential amino acids may reduce the occurrence of infections in rehabilitation patients with brain injury

BACKGROUND

To investigate whether supplementation with oral essential amino acids (EAAs) may reduce the occurrence of nosocomial infection among patients with brain injury (BI: stroke, trauma, anoxic coma).

METHODS

Patients (n = 125; 77 men, 48 women; mean age 63 ± 15 years) with stroke (68.8%), subarachnoid hemorrhage (17.6%), traumatic BI (7.2%), and anoxic BI (6.4%) 88 ± 15 days after the index event. Patients were randomly assigned to 2 months of oral EAAs (n = 63; 8 g/d) or placebo (n = 62).

RESULTS

Over the first month of rehabilitation, there were 60 infections in the whole population of 125 patients (48%); however, the rate was 23.2% lower in the EAA group (23 episodes/63 patients; 36.5%) than in the placebo group (37 episodes/62 patients; 59.7%) (P < .01). The types of infection were similarly distributed between the 2 groups. Serum levels of prealbumin <20 mg/dL and C-reactive protein (CRP) >0.3 mg/dL were the best predictors of future infection (prealbumin: odds ratio [OR] = 4.17, confidence interval [CI] 1.84-9.45, P < .001; CRP: OR = 3.8, CI 1.71-8.44, P < .001).

CONCLUSION

Supplementary EAAs may reduce the occurrence of nosocomial infections in rehabilitation patients with BI. Prealbumin and CRP are the best predictors of future infections.

Arginine and glutamine supplementation to culture media improves the performance of various channel catfish immune cells

Specific components of both the innate and adaptive immune systems of channel catfish were evaluated after supplementation of culture media with arginine (ARG) and/or glutamine (GLN). Primary cell cultures of head-kidney macrophages (MØ) were used for phagocytic and bactericidal assays against Edwardsiella ictaluri. Additionally, proliferation assays were conducted with naïve peripheral blood lymphocytes (PBL) exposed to non-specific mitogens. To indirectly assess amino acid utilization of both MØ and PBL, amino acid levels, with emphasis on ARG and GLN, were evaluated in the basal medium before and after activation or mitogenic exposure. After bactericidal and proliferation assays, the sum of the media free amino acid pool significantly (P < 0.05) decreased 23% and 45%, respectively. Glutamine levels in medium decreased by 38% and ARG by 18% during the bactericidal assay. Also, decreases of 52 and 46% from initial values were found after the proliferation assay for GLN and ARG, respectively. Macrophage phagocytosis and killing ability was significantly (P < 0.05) enhanced by ARG supplementation to culture media regardless of GLN supplementation. Proliferation of naïve T- and B-lymphocytes upon mitogenic exposure was significantly (P < 0.05) enhanced by supplementing ARG and GLN to the media, but limited synergistic effects were observed. These results suggest that in vitro, ARG and GLN are important substrates and immunomodulators of both innate and adaptive responses in fish leukocytes, and further highlights the potential use of ARG and GLN as immunonutrients in aquafeeds.

The randomized comparative pediatric critical illness stress-induced immune suppression (CRISIS) prevention trial

OBJECTIVES

Nosocomial infection/sepsis occurs in up to 40% of children requiring long-term intensive care. Zinc, selenium, glutamine, metoclopramide (a prolactin secretalogue), and/or whey protein supplementation have been effective in reducing infection and sepsis in other populations. We evaluated whether daily nutriceutical supplementation with zinc, selenium, glutamine, and metoclopramide, compared to whey protein, would reduce the occurrence of nosocomial infection/sepsis in this at-risk population.

DESIGN

Randomized, double-blinded, comparative effectiveness trial.

SETTING

Eight pediatric intensive care units in the National Institutes of Child Health and Human Development Collaborative Pediatric Critical Care Research Network.

PATIENTS

Two hundred ninety-three long-term intensive care patients (age 1-17 yrs) expected to require >72 hrs of invasive care.

INTERVENTIONS

Patients were stratified according to immunocompromised status and center and then were randomly assigned to receive daily enteral zinc, selenium, glutamine, and intravenous metoclopramide (n = 149), or daily enteral whey protein (n = 144) and intravenous saline for up to 28 days of intensive care unit stay. The primary end point was time to development of nosocomial sepsis/infection. The analysis was intention to treat.

MEASUREMENTS AND MAIN RESULTS

There were no differences by assigned treatment in the overall population with respect to time until the first episode of nosocomial infection/sepsis (median whey protein 13.2 days vs. zinc, selenium, glutamine, and intravenous metoclopramide 12.1 days; p = .29 by log-rank test) or the rate of nosocomial infection/sepsis (4.83/100 days whey protein vs. 4.99/100 days zinc, selenium, glutamine, and intravenous metoclopramide; p = .81). Only 9% of the 293 subjects were immunocompromised and there was a reduction in rate of nosocomial infection/sepsis with zinc, selenium, glutamine, and intravenous metoclopramide in this immunocompromised group (6.09/100 days whey protein vs. 1.57/100 days zinc, selenium, glutamine, and intravenous metoclopramide; p = .011).

CONCLUSION

Compared with whey protein supplementation, zinc, selenium, glutamine, and intravenous metoclopramide conferred no advantage in the immune-competent population. Further evaluation of zinc, selenium, glutamine, and intravenous metoclopramide supplementation is warranted in the immunocompromised long-term pediatric intensive care unit patient.

Dietary arginine and repeated handling increase disease resistance and modulate innate immune mechanisms of Senegalese sole (Solea senegalensis Kaup, 1858)

Stress is known to impair immune function and disease resistance in fish. In the present study, repeated handling was employed as a chronic stressor in order to verify whether its attributed immunosuppressive effects could be minimized by dietary arginine supplementation. Therefore, Senegalese sole (Solea senegalensis) were air exposed daily for 3 min during 14 days (handling) or left undisturbed (control). In addition, both control and handled specimens were fed 3 diets with graded levels of arginine (Arg 4.4, Arg 5.7 and Arg 6.9 g 16 g(-1) N). Following the 14 days stress challenge and feeding on those diets, fish were infected with Photobacterium damselae subsp. piscicida (strain PC566.1; LD(50) 5 × 10(3) cfu mL(-1)) and fed the same experimental diets. Respiratory burst activity and nitric oxide production of head-kidney leucocytes increased parallel to dietary arginine supplementation. HIF-1, HAMP-1, MIP1-alpha and gLYS expression values and some humoral parameters augmented in control specimens fed the Arg 5.7 and Arg 6.9 diets. Interestingly, repeated acute stress increased both disease resistance and some innate immune mechanisms in handled fish. The role of dietary arginine and repeated handling on Senegalese sole innate immunity and disease resistance are discussed.

A glutamine synthetase inhibitor increases survival and decreases cytokine response in a mouse model of acute liver failure

BACKGROUND

Acute liver failure (ALF) can be induced in mice by administering Escherichia coli lipopolysaccharide (LPS) and D-galactosamine (D-GalN), which induce an inflammatory response involving tumour necrosis factor (TNF)-α production and a hepatocyte-specific transcriptional block. Under these conditions, binding of TNF-α to its cognate receptor on hepatocytes eventually leads to their apoptosis.

AIMS

As part of an effort to identify drugs to treat this disease model, we have investigated whether the glutamine synthetase inhibitor methionine sulfoximine (MSO) could play a protective role, given its effectiveness in the inhibition of brain swelling associated with hyperammonaemia.

METHODS

Mouse survival, glutamine synthetase activity, hepatocyte apoptosis and induction of inflammatory cytokines were measured in mice treated with MSO before an intraperitoneal injection of LPS/D-GalN. The effect of MSO on viability and on TNF-α release was also assessed on inflammatory and liver cells.

RESULTS

We have found that, in mice treated with LPS/D-GalN, MSO (i) drastically increases animal survival; (ii) sharply reduces glutamine synthetase activity, without inhibiting its other target, γ-glutamyl cysteine synthetase; (iii) inhibits death receptor-mediated apoptosis in hepatocytes upstream to cytokine binding; (iv) strongly reduces the overall inflammatory cytokine response, including a significant decrease in TNF-α induction in vivo and ex vivo, and in the interferon-γ level and signalling.

CONCLUSIONS

These results demonstrate that the MSO target glutamine synthetase is required for the early steps of the cytokine response to endotoxins, and that its pharmacological inhibition may be exploited to treat inflammation.

Effects of oral amino acid supplementation on long-term-care-acquired infections in elderly patients

The very high general infection rate (IRI) observed in our Geriatric Intensive Rehabilitation Center (GIRC) led us to investigate whether patient supplementation with essential amino acids (EAAs), modulators of immuno-competence, could reduce IRI. Eighty elderly patients admitted to our GIRC (n=40; age 79.5 ± 7.71; male/female 14/26) or placebo (n=40; age 82.13 ± 6.15; male/female 13/27) were allocated to an 8 g/day oral EAAs group and were surveyed for infections (>48 h from admission) over the first month of their hospital stay. The IRI was 67% for the entire population of patients, 82.5% (33/40 patients) in the placebo group and 52% (21/40 patients) in the EAA group (p<0.02). When patients were divided into infection group (IG) and without-infection group (WIG), independently of post randomization allocation, the WIG had higher levels of serum albumin (p<0.001), blood hemoglobin (Hb) concentration (p=0.01), dietary protein (p=0.008) calorie intakes (p=0.05) but lower serum C-reactive protein (CRP) (p<0.001). The factor of CRP>0.8 mg/dl and Hb ≤ 12 in females, ≤13 in males was associated 4 times and 3.6 times risk of infection, respectively, by sex. EAAs supplementation may lower the risk of infection by 30% in the rehabilitative elderly population. CRP and blood hemoglobin levels can be considered risk markers of future infection.

Effects of dietary arginine on inflammatory mediator and receptor of advanced glycation endproducts (RAGE) expression in rats with streptozotocin-induced type 2 diabetes

Arginine (Arg) is known to possess numerous useful physiological properties and have immunomodulatory effects.In vitrostudies reported that Arg inhibits advanced glycation endproduct (AGE) formation; however, the effects of Arg on the receptor of AGE (RAGE) expression in inflammatory conditions are not clear. The present study investigated the effects of dietary Arg supplementation on inflammatory mediator production and RAGE expression in type 2 diabetic rats. There were one normal control (NC) group and two diabetic groups in the present study. Rats in the NC group were fed with a regular chow diet. One diabetic group (DM) was fed a common semi-purified diet while the other diabetic group received a diet in which part of the casein was replaced by Arg (DM-Arg) for 8 weeks. Diabetes was induced by an intraperitoneal injection of nicotinamide followed by streptozotocin. Rats with blood glucose levels exceeding 1800 mg/l were considered diabetic. Blood samples and the liver and lungs of the animals were collected at the end of the study for further analysis. Results showed that plasma glucose and fructosamine contents were significantly higher in the diabetic groups than those in the NC group. The DM group had higher fructosamine and C-reactive protein than the DM-Arg group. Immunohistochemical staining showed that the expressions of RAGE in liver and lung tissues were significantly lower in the DM-Arg group than in the DM group. These results suggest that supplemental dietary Arg can decrease AGE–RAGE interactions and consequently reduce tissue damage in rats with type 2 diabetes.