Glutamine as an immunonutrient

Bone Broth Benefits: How Its Nutrients Fortify Gut Barrier in Health and Disease

Bone broth is a traditional nutrient revered by different people from ancient times to the modern era as a remedy for various illnesses. This review investigates the nutritional components of bone broth, focusing primarily on the most abundant amino acids and minerals saturated in bone broth and their impact on health, particularly in the context of intestinal barrier integrity, intestinal permeability, inflammation, and their application in inflammatory bowel disease. Through comprehensive reviews of animal and human studies, this research highlights that bone broth includes amino acids (glutamine, glycine, proline, histidine, arginine), minerals (Ca, P, K, Mg, Zn) that are beneficial and not just a traditional remedy, resolving questions that have been posed for generations. The benefits documented for components in bone broth support the enhancement of gut health, alleviate inflammation in the intestinal barrier, improve intestinal barrier function in health and disease states, particularly in inflammatory bowel disease, as well as enhancing nutrient absorption. Bone broth offers a nutrient-dense option for enhancing overall health and may offer an alternative to dietary supplements with claims for enhanced gut health. We aim to foster interest in and provide evidence to substantiate claims for bone broth as a potential remedy, particularly for maintaining remission in conditions like IBD and possibly functional diarrhea and to encourage further research.

Effect of Perioperative Immunonutrition on Early-Postoperative Complications in Patients Undergoing Radical Cystectomy for Bladder Cancer: A Case Series

Objective: The objective was to evaluate the impact of perioperative immunonutrition (IN) on postoperative complications in patients undergoing radical cystectomy (RC) for bladder cancer (BC). Methods: A prospective case series of 19 patients treated with perioperative IN between October 2022 and July 2023 was conducted. Patients received preoperative IN based on nutritional risk and postoperative IN with gradual recovery of normal feeding. The inclusion criteria encompassed clinically node-negative patients without metastatic disease. The outcomes were assessed using Clavien-Dindo classification and included infectious complications, wound healing disorders, ileus, anemia, genitourinary issues, recovery time, and compliance with the nutritional regimen. Results: Sixteen patients (84.2%) experienced complications. Most were low-grade (CD 1-2), with no CD > 3a. Wound disorders affected 10.5% and anemia requiring transfusion occurred in 47.4% of patients, infectious complications were reported in 26.3%, and ileus in 36.8%. The median time to first flatus was 2 days (IQR 2-3), while resumption of oral feeding occurred after 4 days (IQR 2-5), like mobilization (IQR 2-5). The median hospital stay was 14 days (IQR 11-18). Compliance with IN was 78.9%, with gastrointestinal intolerance being the primary cause of discontinuation. Conclusions: Patients with RC undergoing perioperative IN showed low rates of high-grade complications and promising results in bowel function recovery and infection rates. Further randomized controlled trials are required to validate these results.

Impact of perioperative immunonutrition on postoperative outcomes in pancreaticoduodenectomy: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND

This systematic review and meta-analysis aimed to evaluate the impact of perioperative immunonutrition on postoperative outcomes in patients undergoing pancreaticoduodenectomy (PD).

METHODS

Conducted a comprehensive search in PubMed, Embase, Cochrane Library, Medline, and Web of Science databases to identify all randomized controlled trials (RCTs) on the topic of immunonutrition and PD. Subsequently screened literature, extracted data, and assessed the risk of bias in the included studies, and finally conducted a meta-analysis using RevMan 5.3 software.

RESULTS

The analysis included a total of 10 RCTs with 574 patients, among whom 288 were in the immunonutrition group and 283 in the control group. The meta-analysis revealed a significantly lower incidence of postoperative infection-related complications (OR = 0.45; 95% CI: 0.27-0.74; P = 0.002) and severe postoperative complications (OR = 0.61; 95% CI: 0.38-0.98; P = 0.04) in the immunonutrition group compared to the control group. Additionally, patients in the immunonutrition group had a significantly shorter length of hospital stay (MD= -1.87; 95%CI -3.29 - -0.44; P = 0.01). However, the analysis revealed no statistically significant difference in the overall complication rate between the two groups (P = 0.67). Furthermore, the incidence of specific complications and perioperative mortality rates also did not demonstrate any statistically significant differences (all P > 0.05).

CONCLUSIONS

Perioperative immunonutrition in PD patients can reduce postoperative infection-related complications, but more high-quality RCTs are needed for further validation.

Lycium barbarum polysaccharide alleviates ferroptosis in Sertoli cells through NRF2/SLC7A11/GPX4 pathway and ameliorates DEHP-induced male reproductive damage in mice

Di-(2-ethylhexyl)phthalate (DEHP) is a common plasticizer that has been shown to significantly negatively affect male reproductive health. On the other hand, Lycium barbarum polysaccharide (LBP) has been shown to improve reproductive function. Therefore, we hypothesized that LBP may ameliorate DEHP-induced male reproductive damage. Herein, we found that LBP could alleviate DEHP-induced testicular damage and sperm abnormalities. Furthermore, histomorphological analysis of mice testis revealed that LBP primarily ameliorated the DEHP-induced male reproductive damage by targeting Sertoli cells. Moreover, the detection of the function-related genes of Sertoli cells confirmed this finding. The serum of mice in the Control, DEHP, and DEHP+LBP groups was analyzed using non-targeted metabolomics to further elucidate the mechanism of action of LBP in improving DEHP-induced male reproductive damage. According to the results, the differential metabolites were mainly enriched in the glutamate metabolism pathway, implying that LBP may alleviate the ferroptosis-related DEHP-induced testicular injury. Related ferroptosis markers were also found in mice testis. These findings collectively suggest that LBP may ameliorate DEHP-induced testicular injury via alleviating ferroptosis in Sertoli cells. To clarify the specific mechanism, we constructed a cell model in vitro by treating TM4 cells (the Sertoli cell line) with LBP and MEHP (the in vivo DEHP metabolite). Our findings revealed that LBP can improve the function of DEHP-affected Sertoli cells. Furthermore, the analysis of lipid peroxidation, Fe2+ content, and ferroptosis-related protein expressions demonstrated that LBP could ameliorate MEHP-induced ferroptosis in TM4 cells. To clarify the specific mechanism, glutamate metabolism-related proteins involved in the ferroptosis pathway were detected. According to the results, there were significant changes in the expression of NRF2, SLC7A11 and GPX4 proteins, which are involved in the ferroptosis glutamate metabolism pathway. Furthermore, supplementation of NRF2, SLC7A11, and GPX4 inhibitors (ML385, Erastin, and RSL3, respectively) blocked the therapeutic effect of LBP in alleviating MEHP-induced ferroptosis in TM4 cells, implying that LBP could also ameliorate MEHP-induced ferroptosis via the NRF2/SLC7A11/GPX4 pathway. In summary, these findings show that LBP can alleviate DEHP/MEHP-induced ferroptosis through the NRF2/SLC7A11/GPX4 pathway, ameliorating Sertoli cell dysfunction and improving the DEHP-induced male reproductive damage. Therefore, the clinical administration of LBP could be an effective strategy for preventing DEHP-induced male reproductive injury.

Integrated analysis of disulfidoptosis-related genes identifies NRP1 as a novel biomarker promoting proliferation of gastric cancer via glutamine mediated energy metabolism

The incidence and mortality of gastric cancer rank fifth and fourth worldwide among all malignancies, respectively. Additionally, disulfidoptosis, a recently identified form of cellular demise, is closely linked to the initiation and advancement of malignancies. This study aims to create a novel signature of disulfidptosis-related genes (DRGs) and to further explore its association with the tumor immune microenvironment. Based on our comprehensive study, a prognostic signature consisting of 31 DRGs in stomach adenocarcinoma (STAD) was identified and characterized. Through the integrative analyses involving gene expression profiling, machine learning algorithms, and Cox regression models, the prognostic significance of these DRGs was demonstrated. Our findings highlight their strong predictive power in assessing overall survival across diverse patient datasets, and their better performance than traditional clinicopathological factors. Moreover, the DRGs signature showed association with the characteristics of the tumor microenvironment, which has implications for the immune modulation and therapeutic strategies in STAD. Specifically, NRP1 emerged as a key DRG with elevated expression in STAD, showing correlation with the advanced stages of diseases and poorer outcomes. Functional studies further revealed the role of NRP1 in promoting STAD cell proliferation through the modulation of glutamine metabolism. Overall, our study underscores the clinical relevance of DRGs as biomarker and potential therapeutic targets in STAD management, providing insights into disease biology and personalized treatments.

Glutamine enhances pneumococcal growth under methionine semi-starvation by elevating intracellular pH

Introduction

Bacteria frequently encounter nutrient limitation in nature. The ability of living in this nutrient shortage environment is vital for bacteria to preserve their population and important for some pathogenic bacteria to cause infectious diseases. Usually, we study how bacteria survive after nutrient depletion, a total starvation condition when bacteria almost cease growth and try to survive. However, nutrient limitation may not always lead to total starvation.

Methods

Bacterial adaptation to nutrient shortage was studied by determining bacterial growth curves, intracellular pH, intracellular amino acid contents, gene transcription, protein expression, enzyme activity, and translation and replication activities.

Results

No exogenous supply of methionine results in growth attenuation of Streptococcus pneumoniae, a human pathogen. In this paper, we refer to this inhibited growth state between ceased growth under total starvation and full-speed growth with full nutrients as semi-starvation. Similar to total starvation, methionine semi-starvation also leads to intracellular acidification. Surprisingly, it is intracellular acidification but not insufficient methionine synthesis that causes growth attenuation under methionine semi-starvation. With excessive glutamine supply in the medium, intracellular methionine level was not changed, while bacterial intracellular pH was elevated to ~ 7.6 (the optimal intracellular pH for pneumococcal growth) by glutamine deamination, and bacterial growth under semi-starvation was restored fully. Our data suggest that intracellular acidification decreases translation level and glutamine supply increases intracellular pH to restore translation level, thus restoring bacterial growth.

Discussion

This growth with intracellular pH adjustment by glutamine is a novel strategy we found for bacterial adaptation to nutrient shortage, which may provide new drug targets to inhibit growth of pathogenic bacteria under semi-starvation.

Glutamine stimulates the S6K/4E-BP branch of insulin signalling pathway to mitigate human poly(Q) disorders in Drosophila disease models

OBJECTIVE AND METHODS

Since, the S6K/4E-BP sub-pathway can be stimulated by various amino acids; we extended our investigation to examine if oral feeding of amino acids delivers rescue against human poly(Q) toxicity in Drosophila. We utilised Drosophila models of two different poly(Q) disorders to test our hypothesis. Glutamine was fed to the test flies orally mixed in the food. Control and treated flies were then tested for different parameters, such as formation of poly(Q) aggregates and neurodegeneration, to evaluate glutamine's proficiency in mitigating poly(Q) neurotoxicity.

RESULTS

Our study, for the first time, reports that glutamine feeding stimulates the growth promoting S6K/4E-BP branch of insulin signalling pathway and restricts pathogenesis of poly(Q) disorders in Drosophila disease models. We noted that glutamine treatment restricts the formation of neurotoxic poly(Q) aggregates and minimises neuronal deaths. Further, glutamine treatment re-establishes the chromatin architecture by improving the histone acetylation which is otherwise compromised in poly(Q) expressing neuronal cells.

DISCUSSION

Since, the insulin signalling pathway as well as mechanism of action of glutamine are fairly conserved between human and Drosophila, our finding strongly suggests that glutamine holds immense potential to be developed as an intervention therapy against the incurable human poly(Q) disorders.

Associations of Plasma Glutamatergic Metabolites with Alpha Desynchronization during Cognitive Interference and Working Memory Tasks in Asymptomatic Alzheimer's Disease

Electroencephalogram (EEG) studies have suggested compensatory brain overactivation in cognitively healthy (CH) older adults with pathological beta-amyloid(Aβ42)/tau ratios during working memory and interference processing. However, the association between glutamatergic metabolites and brain activation proxied by EEG signals has not been thoroughly investigated. We aim to determine the involvement of these metabolites in EEG signaling. We focused on CH older adults classified under (1) normal CSF Aβ42/tau ratios (CH-NATs) and (2) pathological Aβ42/tau ratios (CH-PATs). We measured plasma glutamine, glutamate, pyroglutamate, and γ-aminobutyric acid concentrations using tandem mass spectrometry and conducted a correlational analysis with alpha frequency event-related desynchronization (ERD). Under the N-back working memory paradigm, CH-NATs presented negative correlations (r = ~-0.74--0.96, p = 0.0001-0.0414) between pyroglutamate and alpha ERD but positive correlations (r = ~0.82-0.95, p = 0.0003-0.0119) between glutamine and alpha ERD. Under Stroop interference testing, CH-NATs generated negative correlations between glutamine and left temporal alpha ERD (r = -0.96, p = 0.037 and r = -0.97, p = 0.027). Our study demonstrated that glutamine and pyroglutamate levels were associated with EEG activity only in CH-NATs. These results suggest cognitively healthy adults with amyloid/tau pathology experience subtle metabolic dysfunction that may influence EEG signaling during cognitive challenge. A longitudinal follow-up study with a larger sample size is needed to validate these pilot studies.

Synergistic effects of Ω-3 polyunsaturated fatty acid supplementation and programmed cell death protein 1 blockade on tumor growth and immune modulation in a xenograft model of esophageal cancer

BACKGROUND

Esophageal cancer, especially esophageal squamous cell carcinoma (ESCC), remains a significant global health challenge with limited survival rates. This study aimed to elucidate the combined effects of immune-modulating nutrition (IMN) with Ω-3 polyunsaturated fatty acid (PUFA) supplementation and anti-programmed cell death protein 1 (PD-1) treatment on tumor growth and immune responses in a xenograft model of ESCC.

METHODS

A total of 36 C57BL/6 mice were used to construct a xenograft model using the mouse esophageal cancer cell line AKR. Mice were subjected to treatment with anti- PD-1 antibody combined with either Ω-3 PUFA-rich or Ω-3 PUFA-deficient nutrition. Tumor growth, immune markers, cytokine profiles, and metabolic changes were evaluated.

RESULTS

The combination of anti-PD-1 and Ω-3 PUFA supplementation significantly inhibited tumor growth more effectively than anti-PD-1 treatment alone. Enhanced expression of immune markers PD-L1 and CD3 was observed in Ω-3 PUFA-fed mice. Additionally, compared with anti-PD-1 therapy and anti-PD-1 plus Ω-3 PUFA-deficient nutrition, Ω-3 PUFAs intensified alterations in key chemokines and cytokines, including elevated IL-12, IFN-γ, and GM-CSF levels, and reduced CXCL12 levels. However, Ω-3 PUFAs did not significantly alter the glycolysis and tryptophan metabolic program induced by anti-PD-1.

CONCLUSION

Our findings indicated the potential synergetic therapeutic benefits of combining anti-PD-1 treatment with Ω-3 PUFA supplementation in ESCC, which offered promising avenue for further research.

Gut microbiota regulates the ALK5/NOX1 axis by altering glutamine metabolism to inhibit ferroptosis of intrahepatic cholangiocarcinoma cells

Intrahepatic cholangiocarcinoma (ICC) is a kind of hepatobiliary tumor that is increasing in incidence and mortality. The gut microbiota plays a role in the onset and progression of cancer, however, the specific mechanism by which the gut microbiota acts on ICC remains unclear. In this study, feces and plasma from healthy controls and ICC patients were collected for 16S rRNA sequencing or metabolomics analysis. Gut microbiota analysis showed that gut microbiota abundance and biodiversity were altered in ICC patients compared with controls. Plasma metabolism analysis showed that the metabolite glutamine content of the ICC patient was significantly higher than that of the controls. KEGG pathway analysis showed that glutamine plays a vital role in ICC. In addition, the use of antibiotics in ICC animals further confirmed that changes in gut microbiota affect changes in glutamine. Further experiments showed that supplementation with glutamine inhibited ferroptosis and downregulated ALK5 and NOX1 expression in HuCCT1 cells. ALK5 overexpression or NOX1 overexpression increased NOX1, p53, PTGS2, ACSL4, LPCAT3, ROS, MDA and Fe2+ and decreased FTH1, SLC7A11 and GSH. Knockdown of NOX1 suppressed FIN56-induced ferroptosis. In vivo, supplementation with glutamine promoted tumor growth. Overexpression of ALK5 repressed tumor growth and induced ferroptosis in nude mice, which could be reversed by the addition of glutamine. Our results suggested that the gut microbiota altered glutamine metabolism to inhibit ferroptosis in ICC by regulating the ALK5/NOX1 axis.

Causal effects of circulating glutamine on colitis, IBD, and digestive system cancers: a Mendelian randomisation study

Backgrounds: There is growing evidence linking glutamine levels to the risk of gastrointestinal diseases, yet the presence of a causal relationship remains uncertain. In this study, we employed a Mendelian randomization (MR) approach to investigate potential causal associations between glutamine and colitis, inflammatory bowel disease (IBD), and digestive tumors. Methods: Genetic instrumental variables for glutamine exposure were identified from a genome-wide association study (GWAS) involving 114,751 participants. We pooled statistics from GWAS of gastrointestinal diseases in European populations, encompassing colitis (cases=1193, controls=461,740), IBD (cases=31,665, controls=33,977), Crohn's disease (cases=17,897, controls=33,977), ulcerative colitis (cases=1,239, controls=990), oesophageal cancer (cases=740, controls=372,016), gastric cancer (cases=6,563, controls=195,745), liver cell carcinoma (cases=168, controls=372,016), hepatic bile duct cancer (cases=418, controls=159,201), pancreatic cancer (cases=1,196, controls=475,049), and colon cancer (cases=1,494, controls=461,439). To ensure the validity of our findings, we utilized several analytical approaches including inverse variance weighted, weighted median, weighted mode, MR-Egger, and simple mode method. Results: Using the IVW method, we found that glutamine levels were inversely associated with colon cancer (OR = 0.998; 95% CI: 0.997-1.000; P = 0.027), colitis (OR = 0.998; 95% CI: 0.997-1.000; P = 0.020), and IBD (OR = 0.551; 95% CI: 0.343-0.886; P = 0.014). Subgroup analysis revealed a negative association between glutamine and Crohn's disease (OR = 0.375; 95% CI: 0.253-0.557; P = 1.11E-06), but not with ulcerative colitis (OR = 0.508; 95% CI: 0.163-1.586; P = 0.244). Glutamine levels showed no significant correlation with oesophageal cancer (OR = 1.000; 95% CI: 0.999-1.001; P = 0.566), gastric cancer (OR = 0.966; 95% CI: 0.832-1.121; P = 0.648), liver cell carcinoma (OR = 1.000; 95% CI: 0.999-1.000; P = 0.397), hepatic bile duct cancer (OR = 0.819; 95% CI: 0.499-1.344; P = 0.430), and pancreatic cancer (OR = 1.130; 95% CI: 0.897-1.423; P = 0.301). Sensitivity analyses also supports this finding, affirming the reliability and robustness of our study. Conclusions: This study suggests that blood glutamine levels in European populations may lower the risk of colon cancer, colitis, and IBD, particularly Crohn's disease. Nevertheless, additional research involving a diverse range of ancestries is imperative to corroborate this causal relationship.

Pharmaconutrition: Which substrates?

With the term "pharmaconutrition" or "immunonutrition" is intended the use of specific nutritional substrates having the ability of modulating specific mechanisms involved in several immune and inflammatory pathways. To achieve these goals, these substrates have to be administered with over physiologic dose. Glutamine and omega-3 polyunsaturated fatty acids, used as single substrate, did not show clear clinical advantages on solid endpoints such as postoperative complications. Despite several multiple substrate enteral feeds are available on the market, very few of them have been tested in randomized clinical trial to prove efficacy. The most extensive investigated formulation is a combination of arginine, omega-3 fatty acids, ribonucleic acid with or without glutamine. Several meta-analyses of randomized clinical trials have been conducted to compare the effects of enteral immunonutrition with control diets on post-surgical morbidity. The results consistently showed that the use of enteral multiple substrate formulas significantly reduced infectious complications and duration of hospitalization. In a more contemporary view, pharmaconutrition should be tested more accurately in the contest of enhanced recovery programs, during neoadjuvant chemotherapy, and in the prehabilitation setting.

Identification of glutamine metabolism-related gene signature to predict colorectal cancer prognosis

Backgrounds: Colorectal cancer (CRC) is a highly malignant gastrointestinal malignancy with a poor prognosis, which imposes a significant burden on patients and healthcare providers globally. Previous studies have established that genes related to glutamine metabolism play a crucial role in the development of CRC. However, no studies have yet explored the prognostic significance of these genes in CRC. Methods: CRC patient data were downloaded from The Cancer Genome Atlas (TCGA), while glutamine metabolism-related genes were obtained from the Molecular Signatures Database (MSigDB) database. Univariate COX regression analysis and LASSO Cox regression were utilized to identify 15 glutamine metabolism-related genes associated with CRC prognosis. The risk scores were calculated and stratified into high-risk and low-risk groups based on the median risk score. The model's efficacy was assessed using Kaplan-Meier survival analysis and receiver operating characteristic (ROC) curve analysis. Cox regression analysis was employed to determine the risk score as an independent prognostic factor for CRC. Differential immune cell infiltration between the high-risk and low-risk groups was assessed using the ssGSEA method. The clinical applicability of the model was validated by constructing nomograms based on age, gender, clinical staging, and risk scores. Immunohistochemistry (IHC) was used to detect the expression levels of core genes. Results: We identified 15 genes related to glutamine metabolism in CRC: NLGN1, RIMKLB, UCN, CALB1, SYT4, WNT3A, NRCAM, LRFN4, PHGDH, GRM1, CBLN1, NRG1, GLYATL1, CBLN2, and VWC2. Compared to the high-risk group, the low-risk group demonstrated longer overall survival (OS) for CRC. Clinical correlation analysis revealed a positive correlation between the risk score and the clinical stage and TNM stage of CRC. Immune correlation analysis indicated a predominance of Th2 cells in the low-risk group. The nomogram exhibited excellent discriminatory ability for OS in CRC. Immunohistochemistry revealed that the core gene CBLN1 was expressed at a lower level in CRC, while GLYATL1 was expressed at a higher level. Conclusions: In summary, we have successfully identified and comprehensively analyzed a gene signature associated with glutamine metabolism in CRC for the first time. This gene signature consistently and reliably predicts the prognosis of CRC patients, indicating its potential as a metabolic target for individuals with CRC.

The role of amino acid metabolism in autoimmune hepatitis

Autoimmune hepatitis (AIH) is an inflammatory chronic liver disease with persistent and recurrent immune-mediated liver injury. The exact cause of AIH is still not fully understood, but it is believed to be primarily due to an abnormal activation of the immune system, leading to autoimmune injury caused by the breakdown of autoimmune tolerance. Although the pathogenesis of AIH remains unclear, recent studies have shown that abnormalities in amino acid metabolism play significant roles in its development. These abnormalities in amino acid metabolism can lead to remodeling of metabolic processes, activation of signaling pathways, and immune responses, which may present new opportunities for clinical intervention in AIH. In this paper, we first briefly outline the recent progress of clinically relevant research on AIH, focusing on the role of specific amino acid metabolism (including glutamine, cysteine, tryptophan, branched-chain amino acids, etc.) and their associated metabolites, as well as related pathways, in the development of AIH. Furthermore, we discuss the scientific issues that remain to be resolved regarding amino acid metabolism, AIH development and related clinical interventions, with the aim of contributing to the future development of amino acid metabolism-based as a new target for the clinical diagnosis and treatment of AIH.

Integrative analysis reveals that SLC38A1 promotes hepatocellular carcinoma development via PI3K/AKT/mTOR signaling via glutamine mediated energy metabolism

Although hepatocellular carcinoma (HCC) is rather frequent, little is known about the molecular pathways underlying its development, progression, and prognosis. In the current study, we comprehensively analyzed the deferentially expressed metabolism-related genes (MRGs) in HCC based on TCGA datasets attempting to discover the potentially prognostic genes in HCC. The up-regulated MRGs were further subjected to analyze their prognostic values and protein expressions. Twenty-seven genes were identified because their high expressions were significant in OS, PFS, DFS, DSS, and HCC tumor samples. They were then used for GO, KEGG, methylation, genetics changes, immune infiltration analyses. Moreover, we established a prognostic model in HCC using univariate assays and LASSO regression based on these MRGs. Additionally, we also found that SLC38A1, an amino acid metabolism closely related transporter, was a potential prognostic gene in HCC, and its function in HCC was further studied using experiments. We found that the knockdown of SLC38A1 notably suppressed the growth and migration of HCC cells. Further studies revealed that SLC38A1 modulated the development of HCC cells by regulating PI3K/AKT/mTOR signaling via glutamine mediated energy metabolism. In conclusion, this study identified the potentially prognostic MRGs in HCC and uncovered that SLC38A1 regulated HCC development and progression by regulating PI3K/AKT/mTOR signaling via glutamine mediated energy metabolism, which might provide a novel marker and potential therapeutic target in HCC.

Zinc Modulates Glutamine Metabolism in T Cells

SCOPE

Zinc and glutamine are well known to be essential for the function and polarization of immune cells. TH 17 cells are more frequently induced during zinc deficiency and cover their energy requirement mainly through glutaminolysis. A dysregulation of TH 17 cells can contribute to the development of autoimmune diseases. Both inhibition of glutaminolysis and zinc supplementation suppress experimental autoimmune encephalomyelitis in mice. Therefore, the aim of this study is to investigate whether zinc modulates glutaminolysis in T cells.

METHODS AND RESULTS

CD3/CD28 stimulation and mixed lymphocytes culture are used as in vitro models for T cell activation. Then, the glutaminolysis is investigated on mRNA, protein, and functional level. Zinc deficiency and glutaminase (GLS) inhibition decrease immune responses in vitro. Furthermore, extracellular zinc and glutamine levels both modulate glutaminolysis by changing the expression of glutamine transporters and key enzymes. Intriguingly, zinc directly interferes with the activity of GLS both in a cell free system and in the cytosol.

CONCLUSION

Besides T cell subset differentiation, zinc also impacts on the cellular metabolism by inhibiting glutaminolysis. This suggests that zinc deficiency can contribute to the development of autoimmune diseases whereas zinc supplementation can support their therapy.

Plasma metabolome of healthy and Rhodococcus equi-infected foals over time

BACKGROUND

Foals that develop pulmonary ultrasonographic lesions on Rhodococcus equi (R. equi) endemic farms are treated with antibiotics because those at risk of developing clinical pneumonia (~20%) cannot be recognised early. Candidate biomarkers identified using metabolomics may aid targeted treatment strategies against R. equi.

OBJECTIVES

(1) To describe how foal ageing affects their plasma metabolome (birth to 8 weeks) and (2) to establish the effects that experimental infection with Rhodococcus equi (R. equi) has on foal metabolome.

STUDY DESIGN

Experimental study.

METHODS

Nine healthy newborn foals were experimentally infected with R. equi as described in a previous study. Foals were treated with oral antibiotics if they developed clinical pneumonia (n = 4, clinical group) or remained untreated if they showed no signs of disease (n = 5, subclinical group). A group of unchallenged foals (n = 4) was also included in the study. By the end of the study period (8 weeks), all foals were free of disease. This status was confirmed with transtracheal wash fluid evaluation and culture as well as thoracic ultrasonography. Plasma metabolomics was determined by GC-MS weekly for the study duration (8 weeks).

RESULTS

Foals' plasma metabolome was altered by ageing (birth to 8 weeks) and experimental infection with R. equi as demonstrated using multivariate statistical analysis. The intensities of 25 and 28 metabolites were altered by ageing and infection (p < 0.05) respectively. Furthermore, 20 metabolites changed by more than 2-fold between clinical and subclinical groups.

MAIN LIMITATIONS

The number of foals is limited. Foals were experimentally infected with R. equi.

CONCLUSIONS

Ageing and R. equi infection induced changes in the plasma metabolome of foals. These results provide an initial description of foal's plasma metabolome and serve as background for future identification of R. equi pneumonia biomarkers.

Effects of glutamine on plasma protein and inflammation in postoperative patients with colorectal cancer: a meta-analysis of randomized controlled trials

OBJECTIVE

To evaluate the effects of glutamine on the plasma protein and inflammatory responses in colorectal cancer (CRC) patients following radical surgery.

METHODS

We thoroughly retrieved online databases (EMBASE, MEDLINE, PubMed, and others) and selected the randomized controlled trials (RCTs) with glutamine vs. conventional nutrition or blank treatment up until March 2023. The plasma protein associated markers indicators (consisting of albumin (ALB), prealbumin (PA), nitrogen balance (NB), total protein (TP)), inflammatory indicators (including TNF-α, CRP, infectious complications (ICs)), and matching 95% confidence intervals (CIs) were evaluated utilizing the pooled analysis. Subsequently, meta-regression analysis, contour-enhanced funnel plot, Egger's test, and sensitivity analysis were carried out.

RESULTS

We discovered 26 RCTs, included an aggregate of 1678 patients, out of which 844 were classified into the glutamine group whereas 834 were classified into the control group. The findings recorded from pooled analysis illustrated that glutamine substantially enhanced the plasma protein markers (ALB [SMD[random-effect] = 0.79, 95% CI: 0.55 to 1.03, I2 = 79.4%], PA [SMD[random-effect] = 0.94, 95% CI: 0.69 to 1.20, I2 = 75.1%], NB [SMD[random-effect] = 1.11, 95% CI: 0.46 to 1.75, I2 = 86.9%). However, the content of TP was subjected to comparison across the 2 groups, and no statistical significance was found (SMD[random-effect] = - 0.02, 95% CI: - 0.60 to 0.57, P = 0.959, I2 = 89.7%). Meanwhile, the inflammatory indicators (including TNF-α [SMD[random-effect] = - 1.86, 95% CI: - 2.21 to - 1.59, I2 = 56.7%], CRP [SMD[random-effect] = - 1.94, 95% CI: - 2.41 to - 1.48, I2 = 79.9%], ICs [RR[fixed-effect] = 0.31, 95% CI: 0.21 to 0.46, I2 = 0.00%]) were decreased significantly followed by the treatment of glutamine.

CONCLUSIONS

The current study's findings illustrated that glutamine was an effective pharmaco-nutrient agent in treating CRC patients following a radical surgical operation. PROSPERO registration number: CRD42021243327.

Synovial Fluid Metabolome Can Differentiate between Healthy Joints and Joints Affected by Osteoarthritis in Horses

Osteoarthritis (OA) is a common cause of lameness in sport horses with a significant economic impact. The prevention of OA is crucial since no effective treatment is available. This study aimed to apply untargeted metabolomic analysis to investigate the differences in synovial fluid (SF) composition between healthy and OA-affected joints in horses. SF collected from healthy (n.8) and OA (n.11) horses was analyzed using H-NMR analysis. Metabolomic analysis allowed 55 different metabolites to be identified and quantified in SF samples. Nineteen metabolites were found to be differently concentrated in OA compared to control horses. Synovial fluids from the OC group were found to be higher in 1,3-dihydroxyacetone but lower in tryptophan, phenylalanine, tyrosine, uridine, creatinine, creatine, glycine, choline, asparagine, glutamine, arginine, 3-hydroxybutyrate, valine, 2-hydroxyisovalerate, α-ketoisovaleric acid, 3-methyl-2-oxovalerate, 3-hydroxyisobutyrate, isoleucine, and methionine compared to the controls. A variety of SF metabolites significantly changed following joint disease, demonstrating the complex mechanism underlying osteoarthritis in horses and highlighting the value of applying the metabolomic approach in clinical research.

Evaluation of an onco-diet on body composition and inflammatory status of dogs with mammary tumor-Pilot study

A high-protein hypercaloric diet enriched with glutamine and omega-3 polyunsaturated fatty acids was called an onco-diet. The goal was to verify the modulation of the inflammatory response and body composition of female dogs with mammary tumor after mastectomy, during onco-diet consumption, using a randomized, double-blinded, clinical trial. Six bitches (average age of 8.6 years) were allocated into Control Group-diet without glutamine, EPA and DHA supplementation; and six bitches (10.0 years) were allocated into Test-diet enriched with glutamine and omega-3. Serum measurements of TNF-α, IL-6, IL-10, IGF-1, C-reactive protein and determination of body composition were performed at pre- and post-surgical times. Statistical tests were used to compare the nutrient intake and dietary effects on inflammatory variables between the diets. No differences in concentrations of different cytokines (p>0.05) and C-reactive protein (CRP) (p = 0.51) were observed between the groups. The test group had a higher concentration of IGF-1 (p<0.05), higher percentage of muscle mass (p<0.01) and lower body fat (p<0.01), but the difference was present from initial and throughout the study. Onco-diet, enriched with glutamine and omega-3, in the amounts evaluated in this study, was not sufficient to modulate the inflammation and body composition of female dogs with mammary tumors submitted to unilateral mastectomy.

Positive mood-related gut microbiota in a long-term closed environment: a multiomics study based on the "Lunar Palace 365" experiment

BACKGROUND

Psychological health risk is one of the most severe and complex risks in manned deep-space exploration and long-term closed environments. Recently, with the in-depth research of the microbiota-gut-brain axis, gut microbiota has been considered a new approach to maintain and improve psychological health. However, the correlation between gut microbiota and psychological changes inside long-term closed environments is still poorly understood. Herein, we used the "Lunar Palace 365" mission, a 1-year-long isolation study in the Lunar Palace 1 (a closed manned Bioregenerative Life Support System facility with excellent performance), to investigate the correlation between gut microbiota and psychological changes, in order to find some new potential psychobiotics to maintain and improve the psychological health of crew members.

RESULTS

We report some altered gut microbiota that were associated with psychological changes in the long-term closed environment. Four potential psychobiotics (Bacteroides uniformis, Roseburia inulinivorans, Eubacterium rectale, and Faecalibacterium prausnitzii) were identified. On the basis of metagenomic, metaproteomic, and metabolomic analyses, the four potential psychobiotics improved mood mainly through three pathways related to nervous system functions: first, by fermenting dietary fibers, they may produce short-chain fatty acids, such as butyric and propionic acids; second, they may regulate amino acid metabolism pathways of aspartic acid, glutamic acid, tryptophan, etc. (e.g., converting glutamic acid to gamma-aminobutyric acid; converting tryptophan to serotonin, kynurenic acid, or tryptamine); and third, they may regulate other pathways, such as taurine and cortisol metabolism. Furthermore, the results of animal experiments confirmed the positive regulatory effect and mechanism of these potential psychobiotics on mood.

CONCLUSIONS

These observations reveal that gut microbiota contributed to a robust effect on the maintenance and improvement of mental health in a long-term closed environment. Our findings represent a key step towards a better understanding the role of the gut microbiome in mammalian mental health during space flight and provide a basis for future efforts to develop microbiota-based countermeasures that mitigate risks to crew mental health during future long-term human space expeditions on the moon or Mars. This study also provides an essential reference for future applications of psychobiotics to neuropsychiatric treatments. Video Abstract.

The Influence of Alcohol Consumption on Intestinal Nutrient Absorption: A Comprehensive Review

Chronic alcohol use has been attributed to the development of malnutrition. This is in part due to the inhibitory effect of ethanol on the absorption of vital nutrients, including glucose, amino acids, lipids, water, vitamins, and minerals within the small intestine. Recent advances in research, along with new cutting-edge technologies, have advanced our understanding of the mechanism of ethanol's effect on intestinal nutrient absorption at the brush border membrane (BBM) of the small intestine. However, further studies are needed to delineate how ethanol consumption could have an impact on altered nutrient absorption under various disease conditions. Current research has elucidated the relationship of alcohol consumption on glucose, glutamine, vitamins B1 (thiamine), B2 (riboflavin), B9 (folate), C (ascorbic acid), selenium, iron, and zinc absorption within the small intestine. We conducted systematic computerized searches in PubMed using the following keywords: (1) "Alcohol effects on nutrient transport"; (2) "Alcohol mediated malabsorption of nutrients"; (3) "Alcohol effects on small intestinal nutrient transport"; and (4) "Alcohol mediated malabsorption of nutrients in small intestine". We included the relevant studies in this review. The main objective of this review is to marshal and analyze previously published research articles and discuss, in-depth, the understanding of ethanol's effect in modulating absorption of vital macro and micronutrients in health and disease conditions. This could ultimately provide great insights in the development of new therapeutic strategies to combat malnutrition associated with alcohol consumption.

Glutamine ameliorates hyperoxia-induced hippocampal damage by attenuating inflammation and apoptosis via the MKP-1/MAPK signaling pathway in neonatal rats

Glutamine (Gln) is an immunomodulatory protein that mediates oxidative stress, inflammation, and apoptosis, but has not been reported in the treatment of hyperoxia (Hyp)-induced brain injury. The aim of this study was to determine whether Gln could improve hyp-induced brain injury in neonatal rats to and later learning and memory dysfunction, and to explore its possible mechanisms. We prepared a model of neonatal rat brain injury caused by normobaric hyperoxia while administered with Gln for 7 days for evaluation. Learning memory function was assessed with the Morris water maze test. Histological analysis, protein expression analysis, oxidative stress and inflammation level analysis were performed using hippocampal tissue. Gln treatment significantly reduced brain tissue water content, oxidative stress levels, microglia activation and inflammatory factor expression, and attenuated tissue damage and apoptosis in the hippocampal region. Gln ameliorates hyp-induced learning, memory impairment in neonatal rats in water maze test. It also increased MKP-1 protein expression and decreased p-p38, p-ERK and p-JNK. Therefore, it is hypothesized that Gln may exert neuroprotective effects by increasing MKP-1 expression to negatively regulate MAPK signaling, with potential cognitive improvement in hyp-induced brain injury.

Glutaminolysis and CD4+ T-cell metabolism in autoimmunity: From pathogenesis to therapy prospects

The recent increase in the pathogenesis of autoimmune diseases revealed the critical role of T cells. Investigation into immunometabolism has drawn attention to metabolic processes other than glycometabolism. In rapidly dividing immune cells, including T lymphocytes, the consumption of glutamine is similar to or higher than that of glucose even though glucose is abundant. In addition to contributing to many processes critical for cellular integrity and function, glutamine, as the most abundant amino acid, was recently regarded as an immunomodulatory nutrient. A better understanding of the biological regulation of glutaminolysis in T cells will provide a new perspective for the treatment of autoimmune diseases. In this review, we summarized the current knowledge of glutamine catabolism in CD4+ T-cell subsets of autoimmunity. We also focused on potential treatments targeting glutaminolysis in patients with autoimmune diseases. Knowledge of immunometabolism is constantly evolving, and glutamine metabolism may be a potential therapeutic target for autoimmune disease therapy.

The Exploration of Fetal Growth Restriction Based on Metabolomics: A Systematic Review

Fetal growth restriction (FGR) is a common complication of pregnancy and a significant cause of neonatal morbidity and mortality. The adverse effects of FGR can last throughout the entire lifespan and increase the risks of various diseases in adulthood. However, the etiology and pathogenesis of FGR remain unclear. This study comprehensively reviewed metabolomics studies related with FGR in pregnancy to identify potential metabolic biomarkers and pathways. Relevant articles were searched through two online databases (PubMed and Web of Science) from January 2000 to July 2022. The reported metabolites were systematically compared. Pathway analysis was conducted through the online MetaboAnalyst 5.0 software. For humans, a total of 10 neonatal and 14 maternal studies were included in this review. Several amino acids, such as alanine, valine, and isoleucine, were high frequency metabolites in both neonatal and maternal studies. Meanwhile, several pathways were suggested to be involved in the development of FGR, such as arginine biosynthesis, arginine, and proline metabolism, glyoxylate and dicarboxylate metabolism, and alanine, aspartate, and glutamate metabolism. In addition, we also included 8 animal model studies, in which three frequently reported metabolites (glutamine, phenylalanine, and proline) were also present in human studies. In general, this study summarized several metabolites and metabolic pathways which may help us to better understand the underlying metabolic mechanisms of FGR.

Salivary Microbiome Profile of Diabetes and Periodontitis in a Chinese Population

Aim

There is a bidirectional association between diabetes and periodontitis. However, the effect of diabetes on the periodontitis salivary microbiota has not been elucidated. The aim of this study was to determine the effect of the presence of diabetes on the microbiota among Chinese patients with periodontitis.

Materials and Methods

Unstimulated whole saliva samples were collected from the periodontitis with diabetes group (TC), chronic periodontitis group (CP), and periodontally healthy and systemically healthy group (H) by spitting method. Bacterial genomic DNA was PCR-amplified at the V4 variable region of 16S rRNA gene. The library was constructed according to the obtained sequence results, and biological analysis and statistical analysis were carried out. Functional prediction of three groups of microbial communities was performed by the PICRUSt algorithm.

Results

There was no significant difference in bacterial diversity between the TC and CP groups. Compared with the H group, the TC group and CP group presented a higher diversity of salivary flora. Firmicutes, Streptococcus, Haemophilus, Veillonella, and Haemophilus parainfluenzae dominated the H group. Corynebacterium, Leptotrichia, Dialister, Comamonas, Capnocytophaga, Catonella, Filifactor, Campylobacter, Treponema, Campylobacter concisus, Prevotella oralis, and Porphyromonas gingivalis were significantly enriched in the TC and CP groups. Among them, Treponema and P. oralis were the most abundant in the TC group. The PICRUSt results showed that many pathways related to cell motility and functional metabolism of the salivary microbial flora changed in the TC group and the CP group.

Conclusions

Diabetes was not the main factor causing the altered diversity of salivary microbiota in patients with periodontitis; however, the presence of diabetes altered the abundance of some microbiota in saliva.

Effects of Uremic Clearance Granules on p38 MAPK/NF-κB Signaling Pathway, Microbial and Metabolic Profiles in End-Stage Renal Disease Rats Receiving Peritoneal Dialysis

Background

Methods

Results

Conclusion

Immunometabolic analysis shows a distinct cyto-metabotype in Covid-19 compared to sepsis from other causes

Background

In Covid-19, profound systemic inflammatory responses are accompanied by both metabolic risk factors for severity and, separately, metabolic mechanisms have been shown to underly disease progression. It is unknown whether this reflects similar situations in sepsis or is a unique characteristic of Covid-19.

Aims

Define the immunometabolic signature of Covid-19.

Methods

65 patients with Covid-19,19 patients with sepsis and 14 healthy controls were recruited and sampled for plasma, serum and peripheral blood mononuclear cells (PBMCs) through 10 days of critical illness. Metabotyping was performed using the Biocrates p180 kit and multiplex cytokine profiling undertaken. PBMCs underwent phenotyping by flow cytometry. Immune and metabolic readouts were integrated and underwent pathway analysis.

Results

Phopsphatidylcholines (PC) are reduced in Covid-19 but greater than in sepsis. Compared to controls, tryptophan is reduced in Covid-19 and inversely correlated with the severity of the disease and IFN-ɣ concentrations, conversely the kyneurine and kyneurine/tryptophan ratio increased in the most severe cases. These metabolic changes were consistent through 2 pandemic waves in our centre. PD-L1 expression in CD8+ T cells, Tregs and CD14+ monocytes was increased in Covid-19 compared to controls.

Conclusions

In our cohort, Covid-19 is associated with monocytopenia, increased CD14+ and Treg PD-L1 expression correlating with IFN-ɣ plasma concentration and disease severity (SOFA score). The latter is also associated with metabolic derangements of Tryptophan, LPC 16:0 and PCs. Lipid metabolism, in particular phosphatidylcholines and lysophosphatidylcolines, seems strictly linked to immune response in Covid-19. Our results support the hypothesis that IFN-ɣ -PD-L1 axis might be involved in the cytokine release syndrome typical of severe Covid-19 and the phenomenon persisted through multiple pandemic waves despite use of immunomodulation.

Vaccines, Microbiota and Immunonutrition: Food for Thought

Vaccines are among the most effective health measures and have contributed to eradicating some diseases. Despite being very effective, response rates are low in some individuals. Different factors have been proposed to explain why some people are not as responsive as others, but what appears to be of critical importance is the presence of a healthy functioning immune system. In this respect, a key factor in modulating the immune system, both in its adaptive and innate components, is the microbiota. While microbiota can be modulated in different ways (i.e., antibiotics, probiotics, prebiotics), an effective and somewhat obvious mechanism is via nutrition. The science of nutrients and their therapeutic application is called immunonutrition, and it is increasingly being considered in several conditions. Our review will focus on the importance of nutrition and microbiota modulation in promoting a healthy immune system while also discussing the overall impact on vaccination response.

Maternal regulation of biliary disease in neonates via gut microbial metabolites

Maternal seeding of the microbiome in neonates promotes a long-lasting biological footprint, but how it impacts disease susceptibility in early life remains unknown. We hypothesized that feeding butyrate to pregnant mice influences the newborn’s susceptibility to biliary atresia, a severe cholangiopathy of neonates. Here, we show that butyrate administration to mothers renders newborn mice resistant to inflammation and injury of bile ducts and improves survival. The prevention of hepatic immune cell activation and survival trait is linked to fecal signatures of Bacteroidetes and Clostridia and increases glutamate/glutamine and hypoxanthine in stool metabolites of newborn mice. In human neonates with biliary atresia, the fecal microbiome signature of these bacteria is under-represented, with suppression of glutamate/glutamine and increased hypoxanthine pathways. The direct administration of butyrate or glutamine to newborn mice attenuates the disease phenotype, but only glutamine renders bile duct epithelial cells resistant to cytotoxicity by natural killer cells. Thus, maternal intake of butyrate influences the fecal microbial population and metabolites in newborn mice and the phenotypic expression of experimental biliary atresia, with glutamine promoting survival of bile duct epithelial cells.

The pathogenesis of biliary atresia remains poorly understood. Here, the authors report that maternal butyrate treatment alters the gut microbiome and glutamine/hypoxanthine metabolites similar to human subjects, and suppresses biliary atresia in newborn mice.

Meta-analysis of Glutamine on Immune Function and Post-Operative Complications of Patients With Colorectal Cancer

The aim of this meta-analysis was to evaluate the clinical significance of glutamine in the management of patients with colorectal cancer (CRC) after radical operation. Electronic databases, including PubMed, EMBASE, MEDLINE, Cochrane Library, Chinese Biomedical Database (CBM), China National Knowledge Infrastructure (CNKI), VIP medicine information system (VIP), and Wanfang electronic databases were comprehensively searched from inception to 30, July 2021. Prospective randomized trials with glutamine vs. routine nutrition or blank therapy were selected. The immune function related indicators (including IgA, IgG, IgM, CD4+, CD8+, and the ratio of CD4+/CD8+), post-operative complications [including surgical site infection (SSI), anastomotic leakage, and length of hospital stay (LOS)], and corresponding 95% confidence intervals (CIs) were assessed in the pooled analysis. Subsequently, the heterogeneity between studies, sensitivity, publication bias, and meta-regression analysis were performed. Consequently, 31 studies which contained 2,201 patients (1,108 in the glutamine group and 1,093 in the control group) were included. Results of pooled analysis indicated that glutamine significantly improved the humoral immune function indicators [including IgA (SMD = 1.15, 95% CI: 0.72–1.58), IgM (SMD = 0.68, 95% CI: 0.48–0.89), and IgG (SMD = 1.10, 95% CI: 0.70–1.50)], and the T cell immune function indicators [including CD4+ (SMD = 0.76, 95% CI: 0.53–0.99) and the ratio of CD4+/CD8+ (SMD = 0.92, 95% CI: 0.57–1.28)]. Meanwhile, the content of CD8+ was decreased significantly (SMD = −0.50, 95% CI: −0.91 to −0.10) followed by glutamine intervention. Pooled analysis of SSI (RR = 0.48, 95% CI: 0.30–0.75), anastomotic leakage (RR = 0.23, 95% CI: 0.09–0.61), and LOS (SMD = −1.13, 95% CI: −1.68 to −0.58) were decreased significantly in glutamine group compared with control group. Metaregression analysis revealed that the covariate of small-sample effects influenced the robustness and reliability of IgG outcome potentially. Findings of the present work demonstrated that glutamine ought to be applied as an effective immunenutrition therapy in the treatment of patients with CRC after radical surgery. The present meta-analysis has been registered in PROSPERO (no. CRD42021243327).

Systematic Review Registration:https://www.crd.york.ac.uk/PROSPERO, Identifier: CRD42021243327.

Nutrients Interaction with the Immune System

This study described the interactions of different nutritional components with the immune system. A detailed search was carried out on Google Scholar and PubMed databases to find out the relevant research studies using different keywords, such as "Nutrients", "Micronutrients", and "Immune system and micronutrients". Only those papers that discussed the interactions between nutrients and the components of the immune system were included in the study. This research outlined the impact of different vitamins, trace elements or metals, amino acids, and fatty acids on different immune system components. It was found that vitamins, such as vitamin A, D, and C, tend to help immune cell differentiation and enhance the expression of different cytokines. Vitamins also contribute to the proliferation of T and B cells and impact the production of white blood cells. Similarly, trace elements or metals act as enzyme cofactors and control different immune response cycles by controlling the expression of cytokines, chemokines, and other signaling molecules. Moreover, different essential and non-essential amino acids play important roles in immune system development as they are primarily involved in protein synthesis. Amino acids, such as arginine, glutamine, and alanine, modulate the expression of cytokines and also control the migration and transmigration capabilities of macrophages. They also enhance the phagocytic properties of macrophages and neutrophils. In a similar way, fatty acids act as anti-inflammatory agents since they can decrease the expression of major histocompatibility complex class I (MHC-I) and MHC-II. Furthermore, they inhibit the secretion of different inflammatory cytokines. In conclusion, all the components of our daily diet are associated with the development of the immune system, and understanding their interactions is important for future immune therapies and drug development.

Patient Nutrition and Probiotic Therapy in COVID-19: What Do We Know in 2021?

BACKGROUND

The main nutritional consequences of COVID-19 include reduced food intake, hypercatabolism, and rapid muscle wasting. Some studies showed that malnutrition is a significant problem among patients hospitalized due to COVID-19 infection, and the outcome of patients with SARS-CoV-2 is strongly associated with their nutritional status. The purpose of this study was to collect useful information about the possible elements of nutritional and probiotic therapy in patients infected with the SARS-CoV-2 virus.

METHODS

A narrative review of the literature, including studies published up to 13 September 2021.

RESULTS

Probiotics may support patients by inhibiting the ACE2 receptor, i.e., the passage of the virus into the cell, and may also be effective in suppressing the immune response caused by the proinflammatory cytokine cascade. In patients' diet, it is crucial to ensure an adequate intake of micronutrients, such as omega-3 fatty acids (at 2-4 g/d), selenium (300-450 μg/d) and zinc (30-50 mg/d), and vitamins A (900-700 µg/d), E (135 mg/d), D (20,000-50,000 IU), C (1-2 g/d), B6, and B12. Moreover, the daily calorie intake should amount to ≥1500-2000 with 75-100 g of protein.

CONCLUSION

In conclusion, the treatment of gut dysbiosis involving an adequate intake of prebiotic dietary fiber and probiotics could turn out to be an immensely helpful instrument for immunomodulation, both in COVID-19 patients and prophylactically in individuals with no history of infection.

Plasmatic Oxidative and Metabonomic Profile of Patients with Different Degrees of Biliary Acute Pancreatitis Severity

Acute pancreatitis (AP) is an inflammatory process of the pancreas with variable involvement of the pancreatic and peripancreatic tissues and remote organ systems. The main goal of this study was to evaluate the inflammatory biomarkers, oxidative stress (OS), and plasma metabolome of patients with different degrees of biliary AP severity to improve its prognosis. Twenty-nine patients with biliary AP and 11 healthy controls were enrolled in this study. We analyzed several inflammatory biomarkers, multifactorial scores, reactive oxygen species (ROS), antioxidants defenses, and the plasma metabolome of biliary AP and healthy controls. Hepcidin (1.00), CRP (0.94), and SIRI (0.87) were the most accurate serological biomarkers of AP severity. OS played a pivotal role in the initial phase of AP, with significant changes in ROS and antioxidant defenses relating to AP severity. Phenylalanine (p < 0.05), threonine (p < 0.05), and lipids (p < 0.01) showed significant changes in AP severity. The role of hepcidin and SIRI were confirmed as new prognostic biomarkers of biliary AP. OS appears to have a role in the onset and progression of the AP process. Overall, this study identified several metabolites that may predict the onset and progression of biliary AP severity, constituting the first metabonomic study in the field of biliary AP.

Chronic Critical Illness and PICS Nutritional Strategies

The nutritional hallmark of chronic critical illness (CCI) after sepsis is persistent inflammation, immunosuppression, and catabolism syndrome (PICS), which results in global resistance to the anabolic effect of nutritional supplements. This ultimately leaves these patients in a downward phenotypic spiral characterized by cachexia with profound weakness, decreased capacity for rehabilitation, and immunosuppression with the propensity for sepsis recidivism. The persistent catabolism is driven by a pathologic low-grade inflammation with the inability to return to homeostasis and by ongoing increased energy expenditure. Better critical care support systems and advances in technology have led to increased intensive care unit (ICU) survival, but CCI due to PICS with poor long-term outcomes has emerged as a frequent phenotype among ICU sepsis survivors. Unfortunately, therapies to mitigate or reverse PICS-CCI are limited, and recent evidence supports that these patients fail to respond to early ICU evidence-based nutrition protocols. A lack of randomized controlled trials has limited strong recommendations for nutrition adjuncts in these patients. However, based on experience in other conditions characterized by a similar phenotype, immunonutrients aimed at counteracting inflammation, immunosuppression, and catabolism may be important for improving outcomes in PICS-CCI patients. This manuscript intends to review several immunonutrients as adjunctive therapies in treating PICS-CCI.

Non-targeted metabolomics of multiple human cells revealing differential toxic effects of perfluorooctanoic acid

Differences in toxic effects of contaminants among human cells are essential for evaluating their health risks to humans. In this study, non-targeted metabolomics of multiple human cell lines (A549 (lung), DLD-1 (intestine) and L-02 (liver) cells) was used to address the differential toxicity of perfluorooctanoic acid (PFOA). The number of differential metabolites (DMs) identified in the PFOA-treated A549 cells (67) was highest, followed by DLD-1 (12) and L-02 cells (10). The categorization of DMs was almost uniquely specific to each of cell lines. PFOA significantly promoted linoleic acid metabolism in L-02 cells whereas this metabolism was inhibited in the PFOA-treated A549 cells. The levels of interleukin (IL)-1β, IL-6, IL-8 and IL-13 were about 1.5 times higher in the PFOA-treated A549 and L-02 cells than in the controls. PFOA stimulated the biosynthesis of arginine and the metabolism of vitamin B6 in A549 cells. Arginine and vitamin B6 supplemented into cell culture effectively decreased the levels of IL-6 and IL-8. The inhibition of purine metabolism by PFOA resulted in the arrestation of DLD-1 cells at the G₀/G₁-phase. Our results suggest that the differential toxicity of PFOA related to exposure pathways could be elucidated by metabolic profiles specific to various human cells.

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.

Herbal Medicine and Acupuncture Combined Treatment Attenuates Colitis in Rats

This study aimed to verify the efficacy of a combined treatment of Jakyakgamcho-tang (JGT) and acupuncture (CV12, ST25, CV4) on colitis induced by dextrane sulfate sodium (DSS). Changes in immuno-mediated factors and metabolites were investigated. Colitis symptoms such as body weight loss and elevated disease activity index were alleviated by the combined treatment. Moreover, treatment with JGT and acupuncture restored the disturbed architecture of colon by suppressing inflammatory cytokine levels of IFN-[Formula: see text] ([Formula: see text] < 0.05), IL-5 ([Formula: see text] < 0.05), and IL-13 ([Formula: see text] < 0.0001) compared with the DSS group. Analysis of metabolic profiles of serum revealed that treatment groups were clearly separated from the DSS group, suggesting that JGT and acupuncture treatment altered serum metabolites. Furthermore, treatments caused opposite metabolite patterns for dimethylbenzimidazole, 1,5-anhydro-D-glucitol, proline, phosphate, glycolic acid, aspartic acid, tryptophan, phthalic acid, ornithine, and glutamic acid compared with the DSS group. The combined treatment group induced more effective metabolite patterns than the JGT group, implying that acupuncture treatment can restore metabolic changes caused by DSS induction. These results indicate that the simultaneous treatment of JGT administration and acupuncture procedure provides better management of the immune function and inflammatory expression of colitis than a single treatment. It is assumed that intestinal microbial control can be achieved by acupuncture stimulation as well as by taking herbal medicine.

Oral glutamine inhibits tumor growth of gastric cancer bearing mice by improving immune function and activating apoptosis pathway

Gastric cancer is one of the most common cancers in the world. It has been shown that exogenous glutamine (GLN) can inhibit the growth of tumor in vivo, but the relationship between GLN and gastric cancer has not been studied. The gastric cancer bearing mouse model was constructed and taken GLN orally at the same time, and the results found that oral GLN (1 or 2 g/kg/d) significantly inhibited the growth rate of tumor and reduce the weight of tumor tissues. Immunohistochemistry showed that oral GLN significantly reduced the PCNA index, which further proved that GLN could inhibit the growth of tumor cells. At the same time, TUNEL assay showed that oral GLN significantly enhanced the apoptosis levels of tumor cells. In addition, GLN reduced GSH levels in tumor tissues, but increased the levels of GSH in plasma, improved the T-lymphocyte transformation rate and NK cell activity, significantly inhibited the secretion of TNF-α and promoted the secretion of IL-2, thus regulating the immune function in vivo. Further detection of apoptosis pathway showed that oral GLN significantly enhanced the expression of pro-apoptotic factor Bad and inhibited the expression of Bcl-2. Meanwhile, GLN significantly increased the activities of Caspase-3, Caspase-8, caspase-9 and PARP. GSH activator NAC had a similar effect to GLN, which could improve the immune function and activate apoptosis pathway, while GSH inhibitor BSO significantly blocked the regulation of GLN, destroyed the immune balance and inhibited apoptosis, but IL-2 significantly blocked the anti-apoptotic effect of BSO. Therefore, oral GLN can improve immune function and activate apoptosis pathway through GSH, and then inhibit the growth of tumor in vivo.

Host cell glutamine metabolism as a potential antiviral target

A virus minimally contains a nucleic acid genome packaged by a protein coat. The genome and capsid together are known as the nucleocapsid, which has an envelope containing a lipid bilayer (mainly phospholipids) originating from host cell membranes. The viral envelope has transmembrane proteins that are usually glycoproteins. The proteins in the envelope bind to host cell receptors, promoting membrane fusion and viral entry into the cell. Virus-infected host cells exhibit marked increases in glutamine utilization and metabolism. Glutamine metabolism generates ATP and precursors for the synthesis of macromolecules to assemble progeny viruses. Some compounds derived from glutamine are used in the synthesis of purines and pyrimidines. These latter compounds are precursors for the synthesis of nucleotides. Inhibitors of glutamine transport and metabolism are potential candidate antiviral drugs. Glutamine is also an essential nutrient for the functions of leukocytes (lymphocyte, macrophage, and neutrophil), including those in virus-infected patients. The increased glutamine requirement for immune cell functions occurs concomitantly with the high glutamine utilization by host cells in virus-infected patients. The development of antiviral drugs that target glutamine metabolism must then be specifically directed at virus-infected host cells to avoid negative effects on immune functions. Therefore, the aim of this review was to describe the landscape of cellular glutamine metabolism to search for potential candidates to inhibit glutamine transport or glutamine metabolism.

Immunonutritional support as an important part of multidisciplinary anti-cancer therapy

Immunonutrition is one of the most important parts of nutritional treatment in patients with cancer. There are studies which confirm positive effects of using immunonutrition (arginine, glutamine, omega-3 fatty acids, nucleotides, pre- and probiotics) among others on the reduction of the pro-inflammatory cytokines concentrations, shortening of the hospital stay and improvement of the nutritional status. Arginine takes part not only in wound healing process, but also it improves body’s immunity and reduces the incidence of infections. Glutamine reduces the incidence of acute grade 2 and 3 esophagitis and improves quality of life of gastric cancer patients. Omega 3-fatty acids have the ability to inhibit the activity of NF-κB. They also reduce the symptoms of graft-versus-host disease in patients undergoing hematopoietic cell transplantation. Nucleotides support the regeneration of intestinal villi. Probiotics play many roles, mainly inhibit the process of carcinogenesis, reduce the incidence of diarrhea and modify intestinal microbiome. However, there are studies indicating the lack of advantages of using immunonutrition compared to standard nutrition. Currently, there is no clear evidence for the use of formulae enriched with immunonutrients versus standard oral nutritional supplements exclusively in the preoperative period. This review summarizes the current knowledge about the role of immunonutrition in supporting treatment of cancer diseases.

Optimal Nutrition Formulas for Patients Undergoing Surgery for Colorectal Cancer: A Bayesian Network Analysis

Optimal nutrition formulas for colorectal cancer patients underwent surgery remains uncertainty. We constructed an indirect comparison study to assess comparative efficacy of different immunonutrition formulas and standard nutrition in colorectal cancer patients underwent surgery. PubMed, the Cochrane Library, EMBASE, ClinicalTrials.gov and Web of Science databases were searched to identify RCTs that compared immunonutrition with standard nutrition or different immunonutrition formulas. Data on length of hospital stays (LOS), infectious complications (IC), noninfectious complications (NIC) and anastomotic leakage (AL) were extracted from the included RCTs for Bayesian network analysis using a random-effect model. Twelve articles that included 1032 individuals were incorporated into this study. The indirect comparison confirmed the potential improvement of arginine-based immunonutrition on IC (odds ratios [OR] = 0.43, 95%confidence interval [CI]: 0.17 to 0.95), glutamine on NIC (OR = 0.07 CI: 0.00 to 0.78) and LOS (MD=-3.91 CI: -6.33 to -1.69) and omega-3 polyunsaturated fatty acids on LOS (OR=-3.49 CI: -5.46 to -1.00). Results indicated that glutamine had the highest probability of reducing complications and hospital stays. As for colorectal cancer patients underwent surgery, this indirect comparison suggested some superiority of glutamine. Future more RCTs with larger scale are required to provide evidence for the optimal immunonutrition formulas.

Alanyl-glutamine Heals Indomethacin-induced Gastric Ulceration in Rats Via Antisecretory and Anti-apoptotic Mechanisms

OBJECTIVES

Alanylglutamine (AG) is a dipeptide that fuels enterocytes and has a coadjuvant role during gut healing. The current study aimed to investigate the potential ulcer-healing effect of AG in indomethacin-induced gastropathy.

METHODS

Animals (n = 10 rats/group) were randomly allocated into 5 groups. Gastric ulcerated rats were administered AG, AG + dexamethasone, or pantoprazole after indomethacin exposure.

RESULTS

Comparable to pantoprazole, AG inhibited H-KATPase pump, and elevated the pH of gastric juice. Moreover, the dipeptide increased the serum/mucosal contents of glucagon-like peptide-1 (GLP-1), pS473-Akt, and cyclin-D1. On the contrary, AG abated serum tumor necrosis factor-α and gastric mucosal content of pS45-β catenin, pS9-GSK3β, pS133-CREB, pS536-NF-κB, H2O2, claudin-1, and caspase-3. The administration of dexamethasone before AG hampered its effect on almost all the measured parameters.

CONCLUSIONS

AG confers its antiulcerogenic/antisecretory potentials by repressing the proton pump to increase the gastric juice pH via boosting p-CREB, p-Akt, p-GSK-3β, and GLP-1. Also, it inhibits apoptosis through suppressing nuclear factor-kappa B/tumor necrosis factor-α/H2O2/claudin-1 cue. This trajectory contributes to loosen the tight junction priming AG-mediated GLP-1/β-catenin/cyclin-D1 that results in pronounced increase in gastric mucosa proliferation. Therefore, the crosstalk between multiple pathways orchestrates the action of AG against gastric ulceration.

Effects of a diet enriched with eicosapentaenoic, docosahexaenoic and glutamine on cytokines as immunological markers for systemic inflammation in bitches before and after ovariohysterectomy

The post-operative period can generate immunological stress and can be modulated through supplementation with the omega-3 series of polyunsaturated fatty acids. This study aimed to evaluate the effects of diets enriched with high doses of eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids and glutamine on inflammatory mediators in dogs before and after ovariohysterectomy (OVH). Twelve female dogs were divided into two groups: group A was fed a commercial diet without the addition of EPA and DHA, and group B was fed an experimental diet enriched with EPA and DHA (0.2 g/100 kcal). Experimental diet intake initiated 21 days before surgery and continued until 30 days after OVH. Parameters measured were serum cytokines (TNF-α, IL-6 and IL-10), C-reactive protein (CRP), IGF-1, lymphoproliferation and body composition before and after surgery. Statistical analyses were performed with SAS software considering the effects of age and diet and their interactions, and means were compared by the Tukey test. There was no difference between groups in body weight (p = .682), lean mass (p = .101) and body fat (p = .103). There were no group differences in serum concentrations of TNF-α, IL-6, IL-10, IGF-1, CRP and the percentage of lymphocyte proliferation. However, a time effect for TNF-α was observed (p < .001), in which T_0P (10 days after the surgical procedure) presented lower values of this cytokine when compared to the other evaluation time points; and interaction effects between group and time were observed for serum concentrations of IL-6 (p < .001) and IL-10 (p = .002). OVH procedure was not considered invasive enough to increase inflammatory cytokines after 30 days of surgery, as well as the dosage of the EPA and DHA used before and after the surgery did not modulate the inflammatory markers.

Japanese subgingival microbiota in health vs disease and their roles in predicted functions associated with periodontitis

The present study aimed to identify and compare the microbial signatures between periodontally healthy and periodontitis subjects using 454 sequences of 16S rRNA genes. Subgingival plaque samples were collected from ten periodontally healthy subjects and ten matched chronic periodontitis patients. Bacterial DNA was extracted and next-generation sequencing of 16S rRNA genes was performed. The microbial composition differed between healthy subjects and periodontitis patients at all phylogenetic levels. Particularly, 16 species, including Lautropia mirabilis and Neisseria subflava predominated in healthy subjects, whereas nine species, including Porphyromonas gingivalis and Filifactor alocis predominated in periodontitis. UniFrac, a principal coordinate and network analysis, confirmed distinct community profiles in healthy subjects and periodontitis patients. Using predicted function profiling, pathways involved in phenylpropanoid, GPI-anchor biosynthesis, and metabolism of alanine, arginine, aspartate, butanoate, cyanoamino acid, fatty acid, glutamate, methane, proline, and vitamin B6 were significantly over-represented in periodontitis patients. These results highlight the oral microbiota alterations in microbial composition in periodontitis and suggest the genes and metabolic pathways associated with health and periodontitis. Our findings help to further elucidate microbial composition and interactions in health and periodontitis.

Alanyl-glutamine Protects Against Damage Induced by Enteroaggregative Escherichia coli Strains in Intestinal Cells

BACKGROUND

Enteroaggregative Escherichia coli (EAEC) is an important pathogen causing enteric infections worldwide. This pathotype is linked to malnutrition in children from developing countries. Alanyl-glutamine (Ala-Gln) is an immune modulator nutrient that acts during intestinal damage and/or inflammation. This study investigated the effect of EAEC infection and Ala-Gln on cell viability, cell death, and inflammation of intestinal epithelium cells (IEC-6).

METHODS

Cells were infected with an EAEC prototype 042 strain, an EAEC wild-type strain isolated from a Brazilian malnourished child, and a commensal E coli HS. Gene transcription and protein levels of caspases-3, -8, and -9 and cytokine-induced neutrophil chemoattractant 1 (CINC-1/CXCL1) were evaluated using RT-qPCR, western blot analysis, and ELISA.

RESULTS

Infections with both EAEC strains decreased cell viability and induced apoptosis and necrosis after 24 hours. Ala-Gln supplementation increased cell proliferation and reduced cell death in infected cells. Likewise, EAEC strain 042 significantly increased the transcript levels of caspases-3, -8, and -9 when compared to the control group, and Ala-Gln treatment reversed this effect. Furthermore, EAEC induced CXCL1 protein levels, which were also reduced by Ala-Gln supplementation.

CONCLUSION

These findings suggest that EAEC infection promotes apoptosis, necrosis, and intestinal inflammation with involvement of caspases. Supplementation of Ala-Gln inhibits cell death, increases cell proliferation, attenuates mediators associated with cell death, and inflammatory pathways in infected cells.

The Gut-Immune-Brain Axis in Autism Spectrum Disorders; A Focus on Amino Acids

Autism spectrum disorder (ASD) is a range of neurodevelopmental conditions that affect communication and social behavior. Besides social deficits, systemic inflammation, gastrointestinal immune-related problems, and changes in the gut microbiota composition are characteristic for people with ASD. Animal models showed that these characteristics can induce ASD-associated behavior, suggesting an intimate relationship between the microbiota, gut, immune system and the brain in ASD. Multiple factors can contribute to the development of ASD, but mutations leading to enhanced activation of the mammalian target of rapamycin (mTOR) are reported frequently. Hyperactivation of mTOR leads to deficits in the communication between neurons in the brain and to immune impairments. Hence, mTOR might be a critical factor linking the gut-brain-immune axis in ASD. Pharmacological inhibition of mTOR is shown to improve ASD-associated behavior and immune functions, however, the clinical use is limited due to severe side reactions. Interestingly, studies have shown that mTOR activation can also be modified by nutritional stimuli, in particular by amino acids. Moreover, specific amino acids are demonstrated to inhibit inflammation, improve gut barrier function and to modify the microbiota composition. In this review we will discuss the gut-brain-immune axis in ASD and explore the potential of amino acids as a treatment option for ASD, either via modification of mTOR activity, the immune system or the gut microbiota composition.

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.