Arginine intake is associated with oxidative stress in a general population

The use of amino acids and their derivates to mitigate against pesticide-induced toxicity

Exposure to pesticides induces oxidative stress and deleterious effects on various tissues in non-target organisms. Numerous models investigating pesticide exposure have demonstrated metabolic disturbances such as imbalances in amino acid levels within the organism. One potentially effective strategy to mitigate pesticide toxicity involves dietary intervention by supplementing exogenous amino acids and their derivates to augment the body's antioxidant capacity and mitigate pesticide-induced oxidative harm, whose mechanism including bolstering glutathione synthesis, regulating arginine-NO metabolism, mitochondria-related oxidative stress, and the open of ion channels, as well as enhancing intestinal microecology. Enhancing glutathione synthesis through supplementation of substrates N-acetylcysteine and glycine is regarded as a potent mechanism to achieve this. Selection of appropriate amino acids or their derivates for supplementation, and determining an appropriate dosage, are of the utmost importance for effective mitigation of pesticide-induced oxidative harm. More experimentation is required that involves large population samples to validate the efficacy of dietary intervention strategies, as well as to determine the effects of amino acids and their derivates on long-term and low-dose pesticide exposure. This review provides insights to guide future research aimed at preventing and alleviating pesticide toxicity through dietary intervention of amino acids and their derivates.

Longitudinal metabolomics integrated with machine learning identifies novel biomarkers of gestational diabetes mellitus

BACKGROUND

Evidence from longitudinal studies is crucial to enhance our understanding of the role of metabolites in the progression of gestational diabetes mellitus (GDM). Herein, a longitudinal untargeted metabolomic study was conducted to reveal the metabolomic profiles and biomarkers associated with the progression of GDM, and characterize the changing patterns of metabolites.

METHODS

We collected serum samples at three trimesters from 30 patients with GDM and 30 healthy Chinese pregnant women with pre-pregnancy BMI, age, and parity matched, and untargeted metabolomic analysis was performed, followed by machine learning approaches that integrated bootstrap and LASSO. Cluster analysis was conducted to elucidate the patterns of metabolite changes. Pathway analyses were conducted to gain insights into the underlying pathways involved.

RESULTS

A total of 32 metabolites, mainly belonging to amino acid and its derivatives, were significantly associated with GDM across three trimesters, and were clustered into three distinct patterns. Metabolites belonging to phosphatidylcholines, lysophosphatidylcholines, lysophosphatidic acids, and lysophosphatidylethanolamines were consistently upregulated, and 2,3-Dihydroxypropyl dihydrogen phosphate was downregulated in GDM group. Amino acid-related, glycerophospholipid, and vitamin B6 metabolism were enriched in multiple trimesters. The levels of allantoic acid, which was positively correlated with blood glucose, was consistently higher in GDM patients and exhibited good discriminatory ability for GDM in the early and mid-pregnancy.

CONCLUSION

We identified and characterized distinct patterns of metabolites associated with GDM throughout pregnancy, and found that allantoic acid was a potential biomarker for early diagnosis of GDM.

Effect of Diet and Oxidative Stress in the Pathogenesis of Lymphoproliferative Disorders

Lymphomas are a heterogeneous group of pathologies that result from clonal proliferation of lymphocytes. They are classified into Hodgkin lymphoma and non-Hodgkin lymphoma; the latter develops as a result of B, T, or NK cells undergoing malignant transformation. It is believed that diet can modulate cellular redox state and that oxidative stress is implicated in lymphomagenesis by acting on several biological mechanisms; in fact, oxidative stress can generate a state of chronic inflammation through the activation of various transcription factors, thereby increasing the production of proinflammatory cytokines and causing overstimulation of B lymphocytes in the production of antibodies and possible alterations in cellular DNA. The purpose of our work is to investigate the results of in vitro and in vivo studies on the possible interaction between lymphomas, oxidative stress, and diet. A variety of dietary regimens and substances introduced with the diet that may have antioxidant and antiproliferative effects were assessed. The possibility of using nutraceuticals as novel anticancer agents is discussed; although the use of natural substances in lymphoma therapy is an interesting field of study, further studies are needed to define the efficacy of different nutraceuticals before introducing them into clinical practice.

Salivary Malondialdehyde Level as a Lipid Peroxidation Marker in Early Childhood Caries

Background: Early childhood caries (ECC) is an aggressive and multifactorial form of dental caries in children, in which the biomarkers of oxidative stress may increase. Objectives: This study aimed to compare the salivary malondialdehyde (MDA) levels in children with early childhood caries (ECC) and caries-free (CF) children. Methods: To this end, 42 ECC children and 42 CF children, aged 4 - 6 years, were randomly selected from the kindergartens of four socio-economically different districts of Isfahan. An unstimulated saliva sample was obtained from children fasting during the past night using the spitting method. In the laboratory, the MDA levels were evaluated spectrophotometrically. An independent-samples t-test was used to examine the differences between the two groups. Results: The mean salivary MDA level was significantly higher in the ECC group than in the CF group (P = 0.01), and there was no significant relationship between salivary MDA and gender (P = 0.44 in the ECC group, P = 0.30 in the CF group). Moreover, no significant relationship was noticed between MDA with decayed, missing, filled teeth (dmft). Conclusions: The findings documented a relationship between ECC and MDA as one of the products of oxidative stress reactions. Accordingly, the MDA level of saliva can be a critical indicator in determining the status of caries in children.

Discovery of metabolic biomarkers for gestational diabetes mellitus in a Chinese population

Background

Gestational diabetes mellitus (GDM), one of the most common pregnancy complications, can lead to morbidity and mortality in both the mother and the infant. Metabolomics has provided new insights into the pathology of GDM and systemic analysis of GDM with metabolites is required for providing more clues for GDM diagnosis and mechanism research. This study aims to reveal metabolic differences between normal pregnant women and GDM patients in the second- and third-trimester stages and to confirm the clinical relevance of these new findings.

Methods

Metabolites were quantitated with the serum samples of 200 healthy pregnant women and 200 GDM women in the second trimester, 199 normal controls, and 199 GDM patients in the third trimester. Both function and pathway analyses were applied to explore biological roles involved in the two sets of metabolites. Then the trimester stage-specific GDM metabolite biomarkers were identified by combining machine learning approaches, and the logistic regression models were constructed to evaluate predictive efficiency. Finally, the weighted gene co-expression network analysis method was used to further capture the associations between metabolite modules with biomarkers and clinical indices.

Results

This study revealed that 57 differentially expressed metabolites (DEMs) were discovered in the second-trimester group, among which the most significant one was 3-methyl-2-oxovaleric acid. Similarly, 72 DEMs were found in the third-trimester group, and the most significant metabolites were ketoleucine and alpha-ketoisovaleric acid. These DEMs were mainly involved in the metabolism pathway of amino acids, fatty acids and bile acids. The logistic regression models for selected metabolite biomarkers achieved the area under the curve values of 0.807 and 0.81 for the second- and third-trimester groups. Furthermore, significant associations were found between DEMs/biomarkers and GDM-related indices.

Conclusions

Metabolic differences between healthy pregnant women and GDM patients were found. Associations between biomarkers and clinical indices were also investigated, which may provide insights into pathology of GDM.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12986-021-00606-8.

Targeted Metabolomic Profiling Reveals Association Between Altered Amino Acids and Poor Functional Recovery After Stroke

Amino acids have been shown to be among the most important metabolites to be altered following stroke; however, they are a double-edged sword with regard to regulating hemostasis. In this study, we conducted a targeted metabolomic study to examine the association between serum levels of amino acids and functional recovery after stroke. Three hundred and fifty-one patients with stroke admitted to an acute rehabilitation hospital were screened, and 106 patients were selected based on inclusion and exclusion criteria. Recruited patients were stratified using Montebello Rehabilitation Factor Score (MRFS) efficiency. We selected the top (n = 20, 19%) and bottom (n = 20, 19%) of MRFS efficiency for metabolomic analysis. A total of 21 serum amino acids levels were measured using ultra high performance liquid chromatography and mass spectrometry. The normalized data were analyzed by multivariate approaches, and the selected potential biomarkers were combined in different combinations for prediction of stroke functional recovery. The results demonstrated that there were significant differences in leucine-isoleucine, proline, threonine, glutamic acid, and arginine levels between good and poor recovery groups. In the training (0.952) and test (0.835) sets, metabolite biomarker panels composed of proline, glutamic acid, and arginine had the highest sensitivity and specificity in distinguishing good recovery from poor. In particular, arginine was present in the top 10 combinations of the average area under the receiver operating characteristic curve (AUC) test set. Our findings suggest that amino acids related to energy metabolism and excitotoxicity may play an important role in functional recovery after stroke. Therefore, the level of serum arginine has predictive value for the recovery rate after stroke.

Effects of diets high in animal or plant protein on oxidative stress in individuals with type 2 diabetes: A randomized clinical trial

High-protein diet is a promising strategy for diabetes treatment supporting body weight control, improving glycaemic status, cardiovascular risk factors and reducing liver fat. Here, we investigated effects of diets high in animal (AP) or plant (PP) protein on oxidative stress and antioxidant status in individuals with type 2 diabetes (T2DM). 37 obese individuals (age 64.3 ± 1.0 years) with T2DM were randomized to an isocaloric diet (30 energy(E)% protein, 30 E% fat and 40 E% carbohydrates) rich in AP or PP for 6 weeks. Markers of oxidative and nitrosative stress and antioxidant status in plasma and nitrate/nitrite levels in urine were assessed. Gene expression in subcutaneous adipose tissue (SAT) was analysed by RNA-Seq and real-time PCR. Both AP and PP diets similarly reduced plasma levels of malondialdehyde (PAP = 0.003, PPP = 1.6 × 10-4) and protein carbonyls (PAP = 1.2 × 10-4, PPP = 3.0 × 10-5) over 6 weeks. Nitrotyrosine (NT) increased upon both AP and PP diets (PAP = 0.005, PPP = 0.004). SAT expression of genes involved in nitric oxide (NO) and oxidative stress metabolism and urine NO metabolite (nitrate/nitrite) levels were not changed upon both diets. Plasma levels of carotenoids increased upon PP diet, whereas retinol, alpha- and gamma-tocopherol slightly decreased upon both diets. AP and PP diets similarly improve oxidative stress but increase nitrosative stress markers in individuals with T2DM. Mechanisms of the NT regulation upon high-protein diets need further investigation.

Serum metabolite profile associated with incident type 2 diabetes in Koreans: findings from the Korean Genome and Epidemiology Study

The identification of metabolic alterations in type 2 diabetes (T2D) is useful for elucidating the pathophysiology of the disease and in classifying high-risk individuals. In this study, we prospectively examined the associations between serum metabolites and T2D risk in a Korean community-based cohort (the Ansan-Ansung cohort). Data were obtained from 1,939 participants with available metabolic profiles and without diabetes, cardiovascular disease, or cancer at baseline. The acylcarnitine, amino acid, amine, and phospholipid levels in fasting serum samples were analyzed by targeted metabolomics. During the 8-year follow-up period, we identified 282 cases of incident T2D. Of all metabolites measured, 22 were significantly associated with T2D risk. Specifically, serum levels of alanine, arginine, isoleucine, proline, tyrosine, valine, hexose and five phosphatidylcholine diacyls were positively associated with T2D risk, whereas lyso-phosphatidylcholine acyl C17:0 and C18:2 and other glycerophospholipids were negatively associated with T2D risk. The associated metabolites were further correlated with T2D-relevant risk factors such as insulin resistance and triglyceride indices. In addition, a healthier diet (as measured by the modified recommended food score) was independently associated with T2D risk. Alterations of metabolites such as amino acids and choline-containing phospholipids appear to be associated with T2D risk in Korean adults.

Correlation between Oxidative Stress, Nutrition, and Cancer Initiation

Inadequate or excessive nutrient consumption leads to oxidative stress, which may disrupt oxidative homeostasis, activate a cascade of molecular pathways, and alter the metabolic status of various tissues. Several foods and consumption patterns have been associated with various cancers and approximately 30-35% of the cancer cases are correlated with overnutrition or malnutrition. However, several contradictory studies are available regarding the association between diet and cancer risk, which remains to be elucidated. Concurrently, oxidative stress is a crucial factor for cancer progression and therapy. Nutritional oxidative stress may be induced by an imbalance between antioxidant defense and pro-oxidant load due to inadequate or excess nutrient supply. Oxidative stress is a physiological state where high levels of reactive oxygen species (ROS) and free radicals are generated. Several signaling pathways associated with carcinogenesis can additionally control ROS generation and regulate ROS downstream mechanisms, which could have potential implications in anticancer research. Cancer initiation may be modulated by the nutrition-mediated elevation in ROS levels, which can stimulate cancer initiation by triggering DNA mutations, damage, and pro-oncogenic signaling. Therefore, in this review, we have provided an overview of the relationship between nutrition, oxidative stress, and cancer initiation, and evaluated the impact of nutrient-mediated regulation of antioxidant capability against cancer therapy.