Effect of glutamine supplementation on cardiometabolic risk factors and inflammatory markers: a systematic review and meta-analysis

Analysis of metabolites associated with ADIPOQ genotypes in individuals with type 2 diabetes mellitus

Diabetes mellitus (DM) is a significant public health problem and it is known that the identification of molecular markers involved in glycemic control can impact disease control. Although the rs266729 polymorphism located in the promoter of the adiponectin gene (ADP) has been shown to be a candidate for involvement in glycemic control, the genotypic groups have never been characterized in terms of metabolomic aspects. Objective: Analyze the metabolites present in the rs266729 genotype groups. 127 diabetic individuals were compared according to the rs266729 genotype groups CC and GC + GG (RFLP-PCR). Blood plasma metabolites were classified by nuclear magnetic resonance (NMR), and the metabolic pathways of each group using the MetaboAnalyst tool. Insulin therapy (p = 0.049) was more frequent in the GC + GG rs266729 group. Lactate, alanine, glutamine, aspartate, lipid, lysine, isoleucine, citrulline, cholesterol, and fucose impacted the CC group and aspartate, beta-glucose, glutamate, pyruvate, proline, and 2-oxoglutarate impacted the CG + GG group. The glucose-alanine pathway, malate-aspartate transport, and urea cycle impacted the CC group (D-glucose, glutamic acid, L-alanine, oxoglutaric acid, and pyruvic acid). The glutamine/glutamate ratio is likely to be related to the causes of rs266729 influencing the risk of diabetes.

The Preventive Role of Glutamine Supplementation in Cardiac Surgery-Associated Kidney Injury from Experimental Research to Clinical Practice: A Narrative Review

Acute kidney injury represents a significant threat in cardiac surgery regarding complications and costs. Novel preventive approaches are needed, as the therapeutic modalities are still limited. As experimental studies have demonstrated, glutamine, a conditionally essential amino acid, might have a protective role in this setting. Moreover, the levels of glutamine after the cardiopulmonary bypass are significantly lower. In clinical practice, various trials have investigated the effects of glutamine supplementation on cardiac surgery with encouraging results. However, these studies are heterogeneous regarding the selection criteria, timing, dose, outcomes studied, and way of glutamine administration. This narrative review aims to present the potential role of glutamine in cardiac surgery-associated acute kidney injury prevention, starting from the experimental studies and guidelines to the clinical practice and future directions.

Glutamine supplementation alleviated aortic atherosclerosis in mice model and in vitro

This study aimed to clarify the role of glutamine in atherosclerosis and its participating mechanism. Forty C57BL/6J mice were divided into wild control (wild Con), ApoE- /- control (ApoE- /- Con), glutamine + ApoE- /- control (Glut + ApoE- /- Con), ApoE- /- high fat diet (ApoE- /- HFD), and glutamine + ApoE- /- HFD (Glut + ApoE- /- HFD) groups. The degree of atherosclerosis, western blotting, and multiomics were detected at 18 weeks. An in vitro study was also performed. Glutamine treatment significantly decreased the degree of aortic atherosclerosis (p = 0.03). O-GlcNAcylation (O-GlcNAc), IL-1β, IL-1α, and pyruvate kinase M2 (PKM2) in the ApoE- /- HFD group were significantly higher than those in the ApoE- /- Con group (p < 0.05). These differences were attenuated by glutamine treatment (p < 0.05), and aggravated by O-GlcNA transferase (OGT) overexpression in the in vitro study (p < 0.05). Multiomics showed that the ApoE- /- HFD group had higher levels of oxidative stress regulatory molecules (guanine deaminase [GUAD], xanthine dehydrogenase [XDH]), proinflammatory regulatory molecules (myristic acid and myristoleic acid), and stress granules regulatory molecules (caprin-1 and deoxyribose-phosphate aldolase [DERA]) (p < 0.05). These differences were attenuated by glutamine treatment (p < 0.05). We conclude that glutamine supplementation might alleviate atherosclerosis through downregulation of O-GlcNAc, glycolysis, oxidative stress, and proinflammatory pathway.

Analysis of Relationships between Metabolic Changes and Selected Nutrient Intake in Women Environmentally Exposed to Arsenic

Nutrients involved in the metabolism of inorganic arsenic (iAs) may play a crucial role in mitigating the adverse health effects associated with such exposure. Consequently, the objective of this study was to analyze the association between the intake levels of nutrients involved in iAs metabolism and alterations in the metabolic profile during arsenic exposure. The study cohort comprised environmentally exposed women: WL (lower total urinary arsenic (As), n = 73) and WH (higher As, n = 73). The analysis included urinary untargeted metabolomics (conducted via liquid chromatography-mass spectrometry) and the assessment of nutrient intake involved in iAs metabolism, specifically methionine, vitamins B2, B6, and B12, folate, and zinc (based on 3-day dietary records of food and beverages). In the WL group, the intake of all analyzed nutrients exhibited a negative correlation with 5 metabolites (argininosuccinic acid, 5-hydroxy-L-tryptophan, 11-trans-LTE4, mevalonic acid, aminoadipic acid), while in the WH group, it correlated with 10 metabolites (5-hydroxy-L-tryptophan, dihyroxy-1H-indole glucuronide I, 11-trans-LTE4, isovalerylglucuronide, 18-oxocortisol, 3-hydroxydecanedioic acid, S-3-oxodecanoyl cysteamine, L-arginine, p-cresol glucuronide, thromboxane B2). Furthermore, nutrient intake demonstrated a positive association with 3 metabolites in the WL group (inosine, deoxyuridine, glutamine) and the WH group (inosine, N-acetyl-L-aspartic acid, tetrahydrodeoxycorticosterone). Altering the intake of nutrients involved in iAs metabolism could be a pivotal factor in reducing the negative impact of arsenic exposure on the human body. This study underscores the significance of maintaining adequate nutrient intake, particularly in populations exposed to arsenic.

Efficacy of Perioperative Infusion of N(2)-L-alanyl-L-glutamine in Glycemic Control for Patients With Uncontrolled Diabetes Mellitus Presented for Urgent Coronary Artery Bypass Surgery: A Randomized Controlled Trial

OBJECTIVES

To evaluate the efficacy of preoperative glutamine infusion in reducing insulin requirements in patients with uncontrolled type 2 diabetes, defined as glycated hemoglobin (HbA1c) >7%, undergoing urgent coronary artery bypass graft (CABG) surgery.

DESIGN

A randomized controlled trial.

SETTING

At Ain Shams University Hospital, Cardiothoracic Academy.

PARTICIPANTS

Ninety-three patients (of both sexes) with uncontrolled diabetes presenting for urgent CABG were categorized into 2 groups.

INTERVENTIONS

The dipeptiven group (n = 46) was given an infusion of dipeptiven 1.5 mL/kg body weight dissolved in normal saline (200 mL) over 3 hours before surgery. The control group (n = 47) received a normal saline infusion (200 mL).

MEASUREMENTS AND MAIN RESULTS

The dipeptiven group demonstrated statistically significant lower intraoperative (173.74 ± 19.97 mg/dL v 198.22 ±14.64 mg/dL) and postoperative (162.36 ±13.11 mg/dL v 176.13 ±14.86 mg/dL) mean blood glucose levels. In addition, dipeptiven infusion was found to reduce mean total insulin requirements intraoperatively by 3.64 ± 0.56 units/h and postoperatively by 37.109 ± 4.30 units/24 h in comparison to placebo (50.98 ± 16.55 units/24 h and 5.10 ± 2.28 units/h, respectively).

CONCLUSION

A preoperative infusion of dipeptiven can contribute to ameliorating stress hyperglycemia in uncontrolled diabetic patients undergoing urgent CABG.

Dietary Glutamine and Glutamate in Relation to Cardiovascular Disease Incidence and Mortality in the United States Men and Women with Diabetes Mellitus

BACKGROUND

Evidence regarding the potential health effects of dietary amino acids glutamine and glutamate among individuals with type 2 diabetes (T2D) is limited.

OBJECTIVES

The aim was to examine dietary glutamine and glutamate in relation to subsequent risk of cardiovascular disease (CVD) and mortality among individuals with T2D.

METHODS

We prospectively followed 15,040 men and women with T2D at baseline or diagnosed during follow-up (Nurses' Health Study: 1980-2014 and Health Professionals Follow-Up Study: 1986-2018). Diet was repeatedly assessed using validated food frequency questionnaires every 2-4 y. Associations of energy-adjusted glutamine and glutamate intake, as well as their ratio, with CVD risk and mortality, were assessed using Cox proportional-hazards models with adjustments for demographics, dietary and lifestyle factors, and medical history.

RESULTS

During 196,955 and 225,371 person-years of follow-up in participants with T2D, there were 2927 incident CVD cases and 4898 deaths, respectively. Higher intake of glutamine was associated with lower risk of CVD incidence, CVD mortality, and total mortality: comparing extreme quintiles, the hazard ratios (HRs) (95% confidence intervals [CIs]) were 0.88 (0.77, 0.99), 0.78 (0.65, 0.92), and 0.84 (0.76, 0.92), respectively (all P-trend < 0.05). In contrast, higher intake of glutamate was associated with a higher risk of CVD incidence, CVD mortality, and total mortality; the HRs were 1.30 (1.15, 1.46), 1.46 (1.24, 1.72), and 1.20 (1.09, 1.32), respectively (all P-trend < 0.05). Furthermore, comparing extreme quintiles, a higher dietary glutamine-to-glutamate ratio was associated with a lower risk of CVD incidence (0.84 [0.75, 0.95]), CVD mortality (0.66 [0.57, 0.77]), and total mortality (0.82 [0.75, 0.90]). In addition, compared with participants with stable or decreased consumption of glutamine-to-glutamate ratio from prediabetes to postdiabetes diagnosis, those who increased the ratio had a 17% (5%, 27%) lower CVD mortality.

CONCLUSIONS

In adults with T2D, dietary glutamine was associated with a lower risk of CVD incidence and mortality, whereas the opposite was observed for glutamate intake.

Omics biomarkers and an approach for their practical implementation to delineate health status for personalized nutrition strategies

Personalized nutrition (PN) has gained much attention as a tool for empowerment of consumers to promote changes in dietary behavior, optimizing health status and preventing diet related diseases. Generalized implementation of PN faces different obstacles, one of the most relevant being metabolic characterization of the individual. Although omics technologies allow for assessment the dynamics of metabolism with unprecedented detail, its translatability as affordable and simple PN protocols is still difficult due to the complexity of metabolic regulation and to different technical and economical constrains. In this work, we propose a conceptual framework that considers the dysregulation of a few overarching processes, namely Carbohydrate metabolism, lipid metabolism, inflammation, oxidative stress and microbiota-derived metabolites, as the basis of the onset of several non-communicable diseases. These processes can be assessed and characterized by specific sets of proteomic, metabolomic and genetic markers that minimize operational constrains and maximize the information obtained at the individual level. Current machine learning and data analysis methodologies allow the development of algorithms to integrate omics and genetic markers. Reduction of dimensionality of variables facilitates the implementation of omics and genetic information in digital tools. This framework is exemplified by presenting the EU-Funded project PREVENTOMICS as a use case.

Potential Therapies Targeting the Metabolic Reprogramming of Diabetes-Associated Breast Cancer

In recent years, diabetes-associated breast cancer has become a significant clinical challenge. Diabetes is not only a risk factor for breast cancer but also worsens its prognosis. Patients with diabetes usually show hyperglycemia and hyperinsulinemia, which are accompanied by different glucose, protein, and lipid metabolism disorders. Metabolic abnormalities observed in diabetes can induce the occurrence and development of breast cancer. The changes in substrate availability and hormone environment not only create a favorable metabolic environment for tumorigenesis but also induce metabolic reprogramming events required for breast cancer cell transformation. Metabolic reprogramming is the basis for the development, swift proliferation, and survival of cancer cells. Metabolism must also be reprogrammed to support the energy requirements of the biosynthetic processes in cancer cells. In addition, metabolic reprogramming is essential to enable cancer cells to overcome apoptosis signals and promote invasion and metastasis. This review aims to describe the major metabolic changes in diabetes and outline how cancer cells can use cellular metabolic changes to drive abnormal growth and proliferation. We will specifically examine the mechanism of metabolic reprogramming by which diabetes may promote the development of breast cancer, focusing on the role of glucose metabolism, amino acid metabolism, and lipid metabolism in this process and potential therapeutic targets. Although diabetes-associated breast cancer has always been a common health problem, research focused on finding treatments suitable for the specific needs of patients with concurrent conditions is still limited. Most studies are still currently in the pre-clinical stage and mainly focus on reprogramming the glucose metabolism. More research targeting the amino acid and lipid metabolism is needed.

Effect of vitamin D supplementation on cardiac-metabolic risk factors in elderly: a systematic review and meta-analysis of clinical trials

BACKGROUND

There has been a longstanding interest in the potential effect of vitamin D in preventing cardiac-metabolic diseases. However, there are divergent results regarding the impact of vitamin D supplementation (VDS) on managing cardiac-metabolic outcomes in the elderly population.

MATERIAL AND METHOD

We systematically searched electronic databases; Web of Science, PubMed, Scopus, EMBASE, Cochrane, and ProQuest. We included all trials that evaluated the effect of VDS on cardiac-metabolic risk factors in the elderly population, which were published until 30 September 2021. The effects of VDS on cardiac-metabolic outcomes were assessed using standardized mean difference (SMD). A random-effect model was used to pool the SMD and 95% confidence interval (CI).

RESULT

The literature search identified 4409 studies, of which 12 trials met inclusion criteria. Results of random effect meta-analysis indicated a significant reduction in total cholesterol (TC) (SMD: - 0.14 mg/dl; 95% CI: - 0.25, - 0.02) and triglyceride (TG) (SMD: - 0.45 mg/dl; 95% CI: - 0.86, - 0.04) with VDS compared to the placebo. The subgroup analyses revealed that the reduction of TG in patients with diabetes and vitamin D deficiency was significant. Furthermore, short-term intervention (≤ 6 months) induced a significantly lower level of TG and insulin in comparison to longer duration (> 6 months).

CONCLUSION

The study suggests that VDS could improve insulin concentration and dyslipidemia in the elderly population. The systematic review was registered in Alborz university of medical sciences with 2060-01-03-1397 number and the Ethics council IR.ABZUMS.REC.1397.207 number.

Alanyl-Glutamine Protects against Lipopolysaccharide-Induced Liver Injury in Mice via Alleviating Oxidative Stress, Inhibiting Inflammation, and Regulating Autophagy

Acute liver injury is a worldwide problem with a high rate of morbidity and mortality, and effective pharmacological therapies are still urgently needed. Alanyl-glutamine (Ala-Gln), a dipeptide formed from L-alanine and L-glutamine, is known as a protective compound that is involved in various tissue injuries, but there are limited reports regarding the effects of Ala-Gln in acute liver injury. This present study aimed to investigate the protective effects of Ala-Gln in lipopolysaccharide (LPS)-induced acute liver injury in mice, with a focus on inflammatory responses and oxidative stress. The acute liver injury induced using LPS (50 μg/kg) and D-galactosamine (D-Gal) (400 mg/kg) stimulation in mice was significantly attenuated after Ala-Gln treatment (500 and 1500 mg/kg), as evidenced by reduced plasma alanine transaminase (ALT) (p < 0.01, p < 0.001), aspartate transaminase (AST) (p < 0.05, p < 0.001), and lactate dehydrogenase (LDH) (p < 0.01, p < 0.001) levels, and accompanied by improved histopathological changes. In addition, LPS/D-Gal-induced hepatic apoptosis was also alleviated by Ala-Gln administration, as shown by a greatly decreased ratio of TUNEL-positive hepatocytes, from approximately 10% to 2%, and markedly reduced protein levels of cleaved caspase-3 (p < 0.05, p < 0.001) in liver. Moreover, we found that LPS/D-Gal-triggered oxidative stress was suppressed after Ala-Gln treatment, the effect of which might be dependent on the elevation of SOD and GPX activities, and on GSH levels in liver. Interestingly, we observed that Ala-Gln clearly inhibited LPS/D-Gal exposure-induced macrophage accumulation and the production of proinflammatory factors in the liver. Furthermore, Ala-Gln greatly regulated autophagy in the liver in LPS/D-Gal-treated mice. Using RAW264.7 cells, we confirmed the anti-inflammatory role of Ala-Gln-targeting macrophages.

The effects of dietary supplements and natural products targeting glucose levels: an overview

Identifying effective dietary supplements and medicinal herbs has attracted the attention of clinicians and researchers to complement the standard treatment in controlling diabetes mellitus. In the present overview, we aimed to collect studies with the highest level of evidence to shed light on detecting the most effective dietary supplements and medicinal herbs for controlling glycemic status. For the current overview, four electronic databases, including PubMed, Scopus, Web of Science, and Cochrane Library, were systematically searched from inception to 31 December 2020 and then updated until 1 October 2021 to obtain eligible meta-analyses on either dietary supplements or medicinal herbs and their effects on glycemic status. Fasting blood sugar (FBS) and Hemoglobin A1C (HbA1C) were considered as primary outcomes. Finally, ninety-one meta-analyses on dietary supplements (n = 55) and herbs (n = 36) were included. Evidence showed positive effects of chromium, zinc, propolis, aloe vera, milk thistle, fenugreek, cinnamon, ginger, and nettle on FBS and/or HbA1C. However, mostly the heterogeneity (I2) was high. Other supplements and herbs also showed no reduction in glucose levels or their effects were small. Although some dietary supplements and medicinal herbs showed a significant reduction in FBS and/or HbA1C, mostly their effects from the clinical point of view were not remarkable. In addition, due to high heterogeneity, publication bias, and a limited number of included studies in most cases further clinical trials are needed for making decision on anti-diabetic supplement efficacy.