Therapeutic Potential of Citrulline as an Arginine Supplement: A Clinical Pharmacology Review

Bioactives in Oral Nutritional Supplementation: A Pediatric Point of View

BACKGROUND

Oral nutritional supplements (ONSs) are crucial for supporting the nutritional needs of pediatric populations, particularly those with medical conditions or dietary deficiencies. Bioactive compounds within ONSs play a pivotal role in enhancing health outcomes by exerting various physiological effects beyond basic nutrition. However, the comprehensive understanding of these bioactives in pediatric ONSs remains elusive.

OBJECTIVE

This systematic narrative review aims to critically evaluate the existing literature concerning bioactive compounds present in oral nutritional supplements from a pediatric standpoint, focusing on their types, sources, bioavailability, physiological effects, and clinical implications.

METHODS

A systematic search was conducted across the major academic databases, including PubMed, Scopus, and Web of Science, employing predefined search terms related to oral nutritional supplements, bioactives, and pediatrics. Studies published between 2013 and 2024 were considered eligible for inclusion. Data extraction and synthesis were performed according to the PRISMA guidelines.

RESULTS

The initial search yielded 558 of articles, of which 72 met the inclusion criteria. The included studies encompassed a diverse range of bioactive compounds present in pediatric ONS formulations, including, but not limited to, vitamins, minerals, amino acids, prebiotics, probiotics, and phytonutrients. These bioactives were sourced from various natural and synthetic origins and were found to exert beneficial effects on growth, development, immune function, gastrointestinal health, cognitive function, and overall well-being in pediatric populations. However, variations in bioavailability, dosing, and clinical efficacy were noted across different compounds and formulations.

CONCLUSIONS

Bioactive compounds in oral nutritional supplements offer promising avenues for addressing the unique nutritional requirements and health challenges faced by pediatric populations. However, further research is warranted to elucidate the optimal composition, dosage, and clinical applications of these bioactives in pediatric ONS formulations. A deeper understanding of these bioactive compounds and their interplay with pediatric health may pave the way for personalized and effective nutritional interventions in pediatric clinical practice.

Identification of the serum metabolites associated with cow milk consumption in Chinese Peri-/Postmenopausal women

Cow milk consumption (CMC) and downstream alterations of serum metabolites are commonly considered important factors regulating human health status. Foods may lead to metabolic changes directly or indirectly through remodelling gut microbiota (GM). We sought to identify the metabolic alterations in Chinese Peri-/Postmenopausal women with habitual CMC and explore if the GM mediates the CMC-metabolite associations. 346 Chinese Peri-/Postmenopausal women participants were recruited in this study. Fixed effects regression and partial least squares discriminant analysis (PLS-DA) were applied to reveal alterations of serum metabolic features in different CMC groups. Spearman correlation coefficient was computed to detect metabolome-metagenome association. 36 CMC-associated metabolites including palmitic acid (FA(16:0)), 7alpha-hydroxy-4-cholesterin-3-one (7alphaC4), citrulline were identified by both fixed effects regression (FDR < 0.05) and PLS-DA (VIP score > 2). Some significant metabolite-GM associations were observed, including FA(16:0) with gut species Bacteroides ovatus, Bacteroides sp.D2. These findings would further prompt our understanding of the effect of cow milk on human health.

Perspectives on the involvement of the gut microbiota in salt-sensitive hypertension

Salt-sensitivity hypertension (SSH) is an independent predictor of cardiovascular event-related death. Despite the extensiveness of research on hypertension, which covers areas such as the sympathetic nervous system, the renin-angiotensin system, the vascular system, and the immune system, its pathogenesis remains elusive, with sub-optimal blood pressure control in patients. The gut microbiota is an important component of nutritional support and constitutes a barrier in the host. Long-term high salt intake can lead to gut microbiota dysbiosis and cause significant changes in the expression of gut microbiota-related metabolites. Of these metabolites, short chain fatty acids (SCFAs), trimethylamine oxide, amino acids, bile acids, and lipopolysaccharide are essential mediators of microbe-host crosstalk. These metabolites may contribute to the incidence and development of SSH via inflammatory, immune, vascular, and nervous pathways, among others. In addition, recent studies, including those on the histone deacetylase inhibitory mechanism of SCFAs and the blood pressure-decreasing effects of H2S via vascular activation, suggest that several proteins and factors in the classical pathway elicit their effects through multiple non-classical pathways. This review summarizes changes in the gut microbiota and its related metabolites in high-salt environments, as well as corresponding treatment methods for SSH, such as diet management, probiotic and prebiotic use, antibiotic use, and fecal transplantation, to provide new insights and perspectives for understanding SSH pathogenesis and the development of strategies for its treatment.

Mitochondrial encephalopathies and myopathies: Our tertiary center's experience

Mitochondrial diseases have a heterogeneous phenotype and can result from mutations in the mitochondrial or nuclear genomes, constituting a diagnostically and therapeutically challenging group of disorders. We report our center's experience with mitochondrial encephalopathies and myopathies with a cohort of 50 genetically and phenotypically diverse patients followed in the Neurology clinic over the last ten years. Seventeen patients had mitochondrial DNA mutations, presented over a wide range of ages with seizures, feeding difficulties, extraocular movements abnormalities, and had high rates of stroke-like episodes and regression. Twenty-seven patients had nuclear DNA mutations, presented early in life with feeding difficulty, failure-to-thrive, and seizures, and had high proportions of developmental delay, wheelchair dependence, spine abnormalities and dystonia. In six patients, a mutation could not be identified, but they were included for having mitochondrial disease confirmed by histopathology, enzyme analysis and clinical features. These patients had similar characteristics to patients with nuclear DNA mutations, suggesting missed underlying mutations in the nuclear genome. Management was variable among patients, but outcomes were universally poor with severe disability in all cases. Therapeutic entryways through elucidation of disease pathways and remaining unknown genes are acutely needed.

Investigating genetic links between blood metabolites and preeclampsia

BACKGROUND

Observational studies have revealed that metabolic disorders are closely related to the development of preeclampsia (PE). However, there is still a research gap on the causal role of metabolites in promoting or preventing PE. We aimed to systematically explore the causal association between circulating metabolites and PE.

METHODS

Single nucleotide polymorphisms (SNPs) from genome-wide association study (GWAS) of 486 blood metabolites (7,824 participants) were extracted as instrumental variables (P < 1 × 10- 5), GWAS summary statistics for PE were obtained from FinnGen consortium (7,212 cases and 194,266 controls) as outcome, and a two-sample Mendelian randomization (MR) analysis was conducted. Inverse variance weighted (IVW) was set as the primary method, with MR-Egger and weighted median as auxiliary methods; the instrumental variable strength and confounding factors were also assessed. Sensitivity analyses including MR-Egger, Cochran's Q test, MR-PRESSO and leave-one-out analysis were performed to test the robustness of the MR results. For significant associations, repeated MR and meta-analysis were performed by another metabolite GWAS (8,299 participants). Furthermore, significantly associated metabolites were subjected to a metabolic pathway analysis.

RESULTS

The instrumental variables for the metabolites ranged from 3 to 493. Primary analysis revealed a total of 12 known (e.g., phenol sulfate, citrulline, lactate and gamma-glutamylglutamine) and 11 unknown metabolites were associated with PE. Heterogeneity and pleiotropy tests verified the robustness of the MR results. Validation with another metabolite GWAS dataset revealed consistency trends in 6 of the known metabolites with preliminary analysis, particularly the finding that genetic susceptibility to low levels of arachidonate (20:4n6) and citrulline were risk factors for PE. The pathway analysis revealed glycolysis/gluconeogenesis and arginine biosynthesis involved in the pathogenesis of PE.

CONCLUSIONS

This study identifies a causal relationship between some circulating metabolites and PE. Our study presented new perspectives on the pathogenesis of PE by integrating metabolomics with genomics, which opens up avenues for more accurate understanding and management of the disease, providing new potential candidate metabolic molecular markers for the prevention, diagnosis and treatment of PE. Considering the limitations of MR studies, further research is needed to confirm the causality and underlying mechanisms of these findings.

Arginine-NO metabolites are associated with morbidity in single ventricle infants undergoing stage 2 palliation

BACKGROUND

Infants with single ventricle heart disease (SVHD) suffer morbidity from insufficient pulmonary blood flow, which may be related to impaired arginine metabolism. No prior study has reported quantitative mapping of arginine metabolites to evaluate the relationship between circulating metabolite levels and outcomes.

METHODS

Prospective cohort study of 75 SVHD cases peri-Stage 2 and 50 healthy controls. We targeted pre- and post-op absolute serum quantification of 9 key members of the arginine metabolism pathway by tandem mass spectrometry. Primary outcomes were length of stay (LOS) and post-Stage 2 hypoxemia.

RESULTS

Pre-op cases showed alteration in 6 metabolites including decreased arginine and increased asymmetric dimethyl arginine (ADMA) levels compared to controls. Post-op cases demonstrated decreased arginine and citrulline levels persisting through 48 h. Adjusting for clinical variables, lower pre-op and 2 h post-op concentrations of multiple metabolites, including arginine and citrulline, were associated with longer post-op LOS (p < 0.01). Increased ADMA at 24 h was associated with greater post-op hypoxemia burden (p < 0.05).

CONCLUSION

Arginine metabolism is impaired in interstage SVHD infants and is further deranged following Stage 2 palliation. Patients with greater metabolite alterations experience greater post-op morbidity. Decreased arginine metabolism may be an important driver of pathology in SVHD.

IMPACT

Interstage infants with SVHD have significantly altered arginine-nitric oxide metabolism compared to healthy children with deficiency of multiple pathway intermediates persisting through 48 h post-Stage 2 palliation. After controlling for clinical covariates and classic catheterization-derived predictors of Stage 2 readiness, both lower pre-operation and lower post-operation circulating metabolite levels were associated with longer post-Stage 2 LOS while increased post-Stage 2 ADMA concentration was associated with greater post-op hypoxemia. Arginine metabolism mapping offers potential for development using personalized medicine strategies as a biomarker of Stage 2 readiness and therapeutic target to improve pulmonary vascular health in infants with SVHD.

Prognostic implications of the arginine metabolism in patients at nutritional risk: A secondary analysis of the randomized EFFORT trial

BACKGROUND

Arginine, a conditionally essential amino acid, is key component in metabolic pathways including immune regulation and protein synthesis. Depletion of arginine contributes to worse outcomes in severely ill and surgical patient populations. We assessed prognostic implications of arginine levels and its metabolites and ratios in polymorbid medical inpatients at nutritional risk regarding clinical outcomes and treatment response.

METHODS

Within this secondary analysis of the randomized controlled Effect of early nutritional support on Frailty, Functional Outcomes, and Recovery of malnourished medical inpatients Trial (EFFORT), we investigated the association of arginine, its metabolites and ratios (i.e., ADMA and SDMA, ratios of arginine/ADMA, arginine/ornithine, and global arginine bioavailability ratio) measured on hospital admission with short-term and long-term mortality by means of regression analysis.

RESULTS

Among the 231 patients with available measurements, low arginine levels ≤90.05 μmol/l (n = 86; 37 %) were associated with higher all-cause mortality at 30 days (primary endpoint, adjusted HR 3.27, 95 % CI 1.86 to 5.75, p < 0.001) and at 5 years (adjusted HR 1.50, 95 % CI 1.07 to 2.12, p = 0.020). Arginine metabolites and ratios were also associated with adverse outcome, but had lower prognostic value. There was, however, no evidence that treatment response was influenced by admission arginine levels.

CONCLUSION

This secondary analysis focusing on medical inpatients at nutritional risk confirms a strong association of low plasma arginine levels and worse clinical courses. The potential effects of arginine-enriched nutritional supplements should be investigated in this population of patients.

CLINICAL TRIAL REGISTRATION

clinicaltrials.gov as NCT02517476 (registered 7 August 2015).

Pentachlorophenol exposure induced neurotoxicity by disrupting citrulline metabolism in larvae and adult zebrafish

Pentachlorophenol (PCP) is a ubiquitous environmental toxicant with various adverse effects. Although its neurotoxicity has been reported, the underlying mechanism and subsequent detoxification remain unclear. In this study, embryos and adult zebrafish were exposed to PCP to determine its potential neurotoxic mechanism and protective indicators. The survival rate, heart rate, mobility time, active status and moving distance were significantly decreased in larvae after 30 μg/L PCP exposure. Likewise, the mobile time, latency to the first movement, velocity and moving distance of adult zebrafish were significantly reduced by PCP exposure. Untargeted metabolomics analysis of larvae revealed that arginine and proline metabolism was the primary pathway affected by PCP exposure, reflected by increased proline and decreased citrulline (CIT) contents, which were confirmed by quantitative data. PCP exposure suppressed the conversion from arginine to CIT in larvae by downregulating the expression of nos1 and nos2a. Ornithine content was increased in the brains and intestines of adult zebrafish after PCP exposure, which inhibited ornithine catabolism to CIT by downregulating otc, resulting in reduced CIT. Intriguingly, CIT supplementation significantly restored the neurobehavioral defects induced by PCP in larvae and adult zebrafish. CIT supplementation upregulated the expression of ef1α and tuba1 in larvae and inhibited the downregulation of ef1α in the brains of adult zebrafish. Taken together, these results indicated that CIT supplementation could protect against PCP-induced neurotoxicity by upregulating the expression of genes involved in neuronal development and function.

Shuttle between arginine and lysine: influence on cancer immunonutrition

Amino acids which are essential nutrients for all cell types' survival are also recognised to serve as opportunistic/alternative fuels in cancers auxotrophic for specific amino acids. Accordingly, restriction of amino acids has been utilised as a therapeutic strategy in these cancers. Contrastingly, amino acid deficiencies in cancer are found to greatly impair immune functions, increasing mortality and morbidity rates. Dietary and supplemental amino acids in such conditions have revealed their importance as 'immunonutrients' by modulating cellular homeostasis processes and halting malignant progression. L-arginine specifically has attracted interest as an immunonutrient by acting as a nodal regulator of immune responses linked to carcinogenesis processes through its versatile signalling molecule, nitric oxide (NO). The quantum of NO generated directly influences the cytotoxic and cytostatic processes of cell cycle arrest, apoptosis, and senescence. However, L-lysine, a CAT transporter competitor for arginine effectively limits arginine input at high L-lysine concentrations by limiting arginine-mediated effects. The phenomenon of arginine-lysine antagonism can, therefore, be hypothesised to influence the immunonutritional effects exerted by arginine. The review highlights aspects of lysine's interference with arginine-mediated NO generation and its consequences on immunonutritional and anti-cancer effects, and discusses possible alternatives to manage the condition. However, further research that considers monitoring lysine levels in arginine immunonutritional therapy is essential to conclude the hypothesis.

Supplementation with l-arginine and nitrates vs age and individual physiological reactivity

Ageing is a natural ontogenetic phenomenon that entails a decrease in the adaptive capacity of the organism, as a result of which the body becomes less adaptable to stressful conditions. Nitrate and nitrite enter the body from exogenous sources and from nitrification of ammonia nitrogen by intestinal microorganisms. This review considers the mechanisms of action of l-arginine, a known inducer of nitric oxide (NO) biosynthesis, and nitrates as supplements in the processes of ageing and aggravated stress states, in which mechanisms of individual physiological reactivity play an important role. This approach can be used as an element of individual therapy or prevention of premature ageing processes depending on the different levels of initial reactivity of the functional systems. A search was performed of the PubMed, Scopus, and Google Scholar databases (n = 181 articles) and the author's own research (n = 4) up to May 5, 2023. The review presents analyses of data on targeted treatment of NO generation by supplementation with l-arginine or nitrates, which is a promising means for prevention of hypoxic conditions frequently accompanying pathological processes in an ageing organism. The review clarifies the role of the individual state of physiological reactivity, using the example of individuals with a high predominance of cholinergic regulatory mechanisms who already have a significant reserve of adaptive capacity. In studies of the predominance of adrenergic influences, a poorly trained organism as well as an elderly organism correspond to low resistance, which is an additional factor of damage at increased energy expenditure. Conclusion: It is suggested that the role of NO synthesis from supplementation of dietary nitrates and nitrites increases with age rather than from oxygen-dependent biosynthetic reactions from l-arginine supplementation.

Roles of Oxidative Injury and Nitric Oxide System Derangements in Kawasaki Disease Pathogenesis: A Systematic Review

Kawasaki disease (KD) is an acute febrile vasculitis that occurs mostly in children younger than five years. KD involves multiple intricately connected inflammatory reactions activated by a cytokine cascade. Despite therapeutic advances, coronary artery damage may develop in some patients, who will be at risk of clinical cardiovascular events and even sudden death. The etiology of KD remains unclear; however, it may involve both genetic and environmental factors leading to aberrant inflammatory responses. Given the young age of onset, prenatal or perinatal exposure may be etiologically relevant. Multisystem inflammatory syndrome in children, a post-infectious hyper-inflammatory disorder associated with severe acute respiratory syndrome coronavirus 2, has features that overlap with those of KD. Available evidence indicates that vascular endothelial dysfunction is a critical step in the sequence of events leading to the development of cardiovascular lesions in KD. Oxidative stress and the dysregulation of the nitric oxide (NO) system contribute to the pathogenesis of inflammatory responses related to this disease. This review provides current evidence and concepts highlighting the adverse effects of oxidative injury and NO system derangements on the initiation and progression of KD and potential therapeutic strategies for cardiovascular pathologies in affected children.

Probiotic Bacillus subtilis contributes to the modulation of gut microbiota and blood metabolic profile of hosts

Probiotic Bacillus subtilis has beneficial efficacy on host's health. The microbiota-gut-blood system (MGBS) plays a crucial role in maintaining the homeostasis of hosts. However, the mechanism by which the probiotic B. subtilis positively acts on the MGBS of hosts remains unclear. Herein, we used an interspecies animal model to explore the causal associations between this bacterium and the micro-ecology balance and circulatory homeostasis of hosts. Results showed that the body weight of hosts significantly increased after probiotic B. subtilis supplementation (P < 0.05). Enterococcus was found to be the most important microbial marker causing the intergroup differences observed herein, and its relative abundance remarkably increased after B. subtilis supplementation. In addition, the supplementation of B. subtilis induced significant alterations in the levels of circulating metabolites, such as serine, arginine, adenine, uric acid, and pyridoxal (P < 0.05), indicating that B. subtilis modulated the metabolic profile of blood circulation in the host. The metabolisms of amino acids, purine, and vitamin B were the primary pathways modulated by B. subtilis. In conclusion, probiotic B. subtilis substantially introduced subtle but positive changes in the host's gut microbiome, and it promoted the physiological activity of the host by modulating circulating metabolites. The study provides a theoretical reference for the application of probiotic B. subtilis to improve the health state of specific populations.

Nucleic acid-functionalized nanozymes and their applications

Nanozymes are inorganic, organic and metal-organic framework nanoparticles that reveal catalytic functions by emulating native enzyme activities. Recently, these nanozymes have attracted growing scientific interest, finding diverse analytical and medical applications. However, the catalytic activities and functions of nanozymes are limited, due to the lack of substrate binding sites that concentrate on the substrate at the catalytic site (molarity effect), introduce substrate specificity and allow functional complexity of the catalysts (cascaded, switchable and cooperative catalysis). The modification of nanozymes with functional nucleic acids provides means to overcome these limitations and engineer nucleic acid/nanozyme hybrids for diverse applications. This is exemplified with the synthesis of aptananozymes, which are supramolecular aptamer-modified nanozymes. Aptananozymes exhibit combined specific binding and catalytic properties that drive diverse chemical transformations, revealing enhanced catalytic activities, as compared to the separated nanozyme/aptamer constituents. Relationships of structure-catalytic functions in the aptananozyme constructs are demonstrated. In addition, modification of nanozymes exhibiting multimodal catalytic functions with aptamers allows the engineering of nanozyme-based bioreactors for cascaded catalysis. Also, the functionalization of reactive oxygen species (ROS)-generating nanozymes with cancer cell-recognizing aptamers yields aptananozymes for targeted chemodynamic treatment of cancer cells and cancer tumors elicited in mice. Finally, nucleic acid-modified enzyme (glucose oxidase)-loaded metal-organic framework nanoparticles yield switchable biocatalytic nanozymes that drive the ON/OFF biocatalyzed oxidation of Amplex Red, dopamine or the generation of chemiluminescence. Herein, future challenges of the topic are addressed.

The effects of a comparatively higher dose of 1000 mg/kg/d of oral L- or D-arginine on the L-arginine metabolic pathways in male Sprague-Dawley rats

Oral L-arginine supplements are popular mainly for their nitric oxide mediated vasodilation, but their physiological impact is not fully known. L-arginine is a substrate of several enzymes including arginase, nitric oxide synthase, arginine decarboxylase, and arginine: glycine amidinotransferase (AGAT). We have published a study on the physiological impact of oral L- and D-arginine at 500 mg/kg/day for 4 wks in male Sprague-Dawley rats. We investigated the effects of oral L-arginine and D-arginine at a higher dose of 1000 mg/kg/d for a longer treatment duration of 16 wks in 9-week-old male Sprague-Dawley rats. We measured the expression and activity of L-arginine metabolizing enzymes, and levels of their metabolites in the plasma and various organs. L-arginine did not affect the levels of L-arginine and L-lysine in the plasma and various organs. L-arginine decreased arginase protein expression in the upper small intestine, and arginase activity in the plasma. It also decreased AGAT protein expression in the liver, and creatinine levels in the urine. L-arginine altered arginine decarboxylase protein expression in the upper small intestine and liver, with increased total polyamines plasma levels. Endothelial nitric oxide synthase protein was increased with D-arginine, the presumed metabolically inert isomer, but not L-arginine. In conclusion, oral L-arginine and D-arginine at a higher dose and longer treatment duration significantly altered various enzymes and metabolites in the arginine metabolic pathways, which differed from alterations produced by a lower dose shorter duration treatment published earlier. Further studies with differing doses and duration would allow for a better understanding of oral L-arginine uses, and evidence based safe and effective dose range and duration.

COVID-19 Metabolomic-Guided Amino Acid Therapy Protects from Inflammation and Disease Sequelae

The outbreak of coronavirus disease 2019 (COVID-19) has caused a worldwide pandemic since 2019. A metabolic disorder is a contributing factor to deaths from COVID-19. However, the underlying mechanism of metabolic dysfunction in COVID-19 patients and the potential interventions are not elucidated. Here targeted plasma metabolomic is performed, and the metabolite profiles among healthy controls, and asymptomatic, moderate, and severe COVID-19 patients are compared. Among the altered metabolites, arachidonic acid and linolenic acid pathway metabolites are profoundly up-regulated in COVID-19 patients. Arginine biosynthesis, alanine, aspartate, and glutamate metabolism pathways are significantly disturbed in asymptomatic patients. In the comparison of metabolite variances among the groups, higher levels of l-citrulline and l-glutamine are found in asymptomatic carriers and moderate or severe patients at the remission stage. Furthermore, l-citrulline and l-glutamine combination therapy is demonstrated to effectively protect mice from coronavirus infection and endotoxin-induced sepsis, and is observed to efficiently prevent the occurrence of pulmonary fibrosis and central nervous system damage. Collectively, the data reveal the metabolite profile of asymptomatic COVID-19 patients and propose a potential strategy for COVID-19 treatment.

The Effectiveness of L-arginine in Clinical Conditions Associated with Hypoxia

The review summarises the data of the last 50 years on the effectiveness of the amino acid L-arginine in therapeutic practice in conditions accompanied by different-origin hypoxia. The aim of this review was to analyse the literature and our research data on the role of nitric oxide in the modulation of individual physiological reactivity to hypoxia. The review considers the possibility of eliminating methodological conflicts in the case of L-arginine, which can be solved by taking into account individual physiological reactivity (or the hypoxia resistance factor). Considerable attention is paid to genetic and epigenetic mechanisms of adaptation to hypoxia and conditions of adaptation in different models. The article presents data on the clinical effectiveness of L-arginine in cardiovascular system diseases (hypertension, atherosclerosis, coronary heart disease, etc.) and stress disorders associated with these diseases. The review presents a generalised analysis of techniques, data on L-arginine use by athletes, and the ambiguous role of NO in the physiology and pathology of hypoxic states shown via nitric oxide synthesis. Data on the protective effects of adaptation in the formation of individual high reactivity in sportsmen are demonstrated. The review demonstrates a favourable effect of supplementation with L-arginine and its application depending on mitochondrial oxidative phosphorylation processes and biochemical indices in groups of individuals with low and high capacity of adaptation to hypoxia. In individuals with high initial anti-hypoxic reserves, these favourable effects are achieved by the blockade of NO-dependent biosynthesis pathways. Therefore, the methodological tasks of physiological experiments and the therapeutic consequences of treatment should include a component depending on the basic level of physiological reactivity.

Antioxidant and Antibacterial Properties of a Functional Sports Beverage Formulation

Athletes often consume functional beverages in order to improve performance and reduce oxidative stress caused by high-intensity exercise. The present study aimed to evaluate the antioxidant and antibacterial properties of a functional sports beverage formulation. The beverage's antioxidant effects were assessed on human mesenchymal stem cells (MSCs) by determining thiobarbituric acid reactive substances (TBARS; TBARS levels decreased significantly by 52.67% at 2.0 mg/mL), total antioxidant capacity (TAC; TAC levels increased significantly by 80.82% at 2.0 mg/mL) and reduced glutathione (GSH; GSH levels increased significantly by 24.13% at 2.0 mg/mL) levels. Furthermore, the beverage underwent simulated digestion following the INFOGEST protocol to assess its oxidative stability. The analysis of the total phenolic content (TPC) using the Folin-Ciocalteu assay revealed that the beverage contained a TPC of 7.58 ± 0.066 mg GAE/mL, while the phenolics identified by HPLC were catechin (2.149 mg/mL), epicatechin (0.024 mg/mL), protocatechuic acid (0.012 mg/mL), luteolin 7-glucoside (0.001 mg/mL), and kaempferol-3-O-β-rutinoside (0.001 mg/mL). The beverage's TPC was strongly correlated with TAC (R² = 896). Moreover, the beverage showcased inhibitory and bacteriostatic effects against Staphylococcus aureus and Pseudomonas aeruginosa. Lastly, the sensory acceptance test demonstrated that the functional sports beverage was well accepted by the assessors.

Supplementation with Nitric Oxide Precursors for Strength Performance: A Review of the Current Literature

Nitric-oxide-stimulating dietary supplements are widely available and marketed to strength athletes and weightlifters seeking to increase muscle performance and augment training adaptations. These supplements contain ingredients classified as nitric oxide (NO) precursors (i.e., "NO boosters"). Endogenous NO is generated via a nitric oxide synthase (NOS)-dependent pathway and a NOS-independent pathway that rely on precursors including L-arginine and nitrates, with L-citrulline serving as an effective precursor of L-arginine. Nitric oxide plays a critical role in endothelial function, promoting relaxation of vascular smooth muscle and subsequent dilation which may favorably impact blood flow and augment mechanisms contributing to skeletal muscle performance, hypertrophy, and strength adaptations. The aim of this review is to describe the NO production pathways and summarize the current literature on the effects of supplementation with NO precursors for strength and power performance. The information will allow for an informed decision when considering the use of L-arginine, L-citrulline, and nitrates to improve muscular function by increasing NO bioavailability.

Comparative plasma and urine metabolomics analysis of juvenile and adult canines

Background and aims

The metabolomic profile of a biofluid can be affected by age, and thus provides detailed information about the metabolic alterations in biological processes and reflects the in trinsic rule regulating the growth and developmental processes.

Methods

To systemically investigate the characteristics of multiple metabolic profiles associated with canine growth, we analyzed the metabolomics in the plasma and urine samples from 15 young and 15 adult beagle dogs via UHPLC-Q-TOFMS-based metabolomics. Blood routine and serum biochemical analyses were also performed on fasting blood samples.

Results

The metabolomics results showed remarkable differences in metabolite fingerprints both in plasma and urine between the young and adult groups. The most obvious age-related metabolite alterations include decreased serumlevels of oxoglutaric acid and essential amino acids and derivatives but increased levels of urine levels of O-acetylserine. These changes primarily involved in amino acid metabolism and bile secretion pathways. We also found that the levels of glutamine were consistently higher in both serum and urine of adults, while N-acetylhistamine and uracil concentrations were much lower in the adult group compared to younger ones.

Conclusion

Our study provides a whole metabolic profile of serum and urine characteristics of young and adult canines, identifying several metabolites that were significantly associated with age change, which provides theoretical support for the nutrition-related research and age-related homeostasis maintenance in dogs.

Oral Arginine Supplementation in Healthy Individuals Performing Regular Resistance Training

Resistance exercise training is well documented as having cardiovascular benefits, but paradoxically, it seems to increase arterial stiffness, favoring the development of high blood pressure. The present study investigates the potential effects of oral supplementation with arginine in healthy individuals performing exercise resistance training. We studied 70 non-smoking male subjects between the ages of 30 and 45 with normal or mildly increased blood pressure on ambulatory monitoring (for 24 h) and normal blood samples and echocardiography, who performed regular resistance exercise training for at least five years with a minimum of three workouts per week. They were divided into two groups in a random manner: 35 males were placed in the arginine group (AG) that followed a 6-month supplementation of their regular diets with 5 g of oral arginine powder taken before their exercise workout, and the control (non-arginine) group (NAG) consisted of 35 males. All subjects underwent body composition analysis, 24 h blood pressure monitoring and pulse wave analysis at enrollment and at six months. After six months of supplementation, blood pressure values did not change in the NAG, while in the AG, we found a decrease of 5.6 mmHg (p < 0.05) in mean systolic blood pressure and a decrease of 4.5 mmHg (p < 0.05) in diastolic values. There was also a 0.62% increase in muscle mass in the AG vs. the NAG (p < 0.05), while the body fat decreased by 1% (p < 0.05 in AG vs. NAG). Overall, the AG gained twice the amount of muscle mass and lost twice as much body fat as the NAG. No effects on the mean weighted average heart rate were recorded in the subjects. The results suggest that oral supplementation with arginine can improve blood pressure and body composition, potentially counteracting the stress induced by resistance exercise training. Supplementation with arginine can be a suitable adjuvant for these health benefits in individuals undertaking regular resistance training.

Differential metabolites in cirrhotic patients with hepatitis B and muscle mass loss

Background

Sarcopenia leads to complications (infections, hepatic encephalopathy and ascites) and poor overall survival in patients with cirrhosis, in which the phenotypic presentation is loss of muscle mass. This study aimed to reveal the metabolic profile and identify potential biomarkers in cirrhotic patients with hepatitis B virus and muscle mass loss.

Method

Twenty decompensated cirrhotic patients with HBV and muscle mass loss were designated Group S; 20 decompensated cirrhotic patients with HBV and normal muscle mass were designated Group NS; and 20 healthy people were designated Group H. Muscle mass loss was defined as the skeletal muscle mass index less than 46.96 cm²/m² for males and less than 32.46 cm²/m² for females. Gas chromatography-mass spectrometry was used to explore the distinct metabolites and pathways in the three groups.

Results

Thirty-seven metabolic products and 25 associated metabolic pathways were significantly different in the Group S patients from Group NS patients. Strong predictive value of 11 metabolites (inosine-5'-monophosphate, phosphoglycolic acid, D-fructose-6-phosphate, N-acetylglutamate, pyrophosphate, trehalose-6-phosphate, fumaric acid, citrulline, creatinine, (r)-3-hydroxybutyric acid, and 2-ketobutyric acid) were selected as potential biomarkers in Group S patients compared with Group NS patients. Two pathways may be associated with loss of muscle mass in patients with liver cirrhosis: amino acid metabolism and central carbon metabolism in cancer.

Conclusion

Seventy differential metabolites were identified in patients who have liver cirrhosis and loss of muscle mass compared with patients who have cirrhosis and normal muscle mass. Certain biomarkers might distinguish between muscle mass loss and normal muscle mass in HBV-related cirrhosis patients.

Determination of equilibria constants of arginine:glycine amidinotransferase (AGAT)-catalyzed reactions using concentrations of circulating amino acids

Arginine:glycine amidinotransferase (AGAT) catalyzes mainly two reactions that generate 1) L-homoarginine (hArg) from L-arginine and L-lysine (K_harg) and 2) guanidinoacetate (GAA) and L-ornithine from L-arginine and glycine (K_gaa). Previously, we found that pharmacological treatment of Becker muscular dystrophy (BMD) patients with metformin or L-citrulline resulted in antidromic effects on serum hArg and GAA concentrations, seemingly acting as an inhibitor and effector of AGAT activity, respectively. Here, we used data of this study as a model to determine K_harg and K_gaa values by using the concentrations of the participating amino acids measured in serum samples of the BMD patients. The study aimed to prove the general utility of this approach to investigate effects of amino acids and drugs on AGAT-catalyzed reactions in vivo in humans.

Study of phytochemical compounds of Plantago major leaves grown in Kazakhstan

Leaves of Plantago major have been used for centuries to treat diseases relating to skin, digestive organs and blood circulation like wounds, inflammation and hypertension. P. major leaves contain biologically active substance and naturally compounds such as essential oils, minerals and amino acids beside polysaccharides, lipids, caffeic acid and its derivatives, iridoid glycosides, flavonoids and terpenoids. This work carried out an examination of Plantago major leaves in terms of phytochemical composition of methanol extract. The leaves contents in chosen nutrients, specifically amino acids and minerals, are moreover depicted. Gas Chromatography -Mass Spectrometry analysis identified the presence of 31 phytochemical compounds and a total amount of 20 amino acids (essential and nonessential) justifying its use as drugs and biological active supplements and its mineral content showed the presence of 7 essential chemical elements in Plantago major leaves. Nonetheless, additional research into this plant is needed because it has the potential to be used to development of new drugs and biological active supplements.

Arginine for the Treatment of Mitochondrial Encephalopathy, Lactic Acidosis, and Stroke-Like Episodes: A Systematic Review

Mitochondrial encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) syndrome is a mitochondrial disease that lacks a definitive treatment. Lately, there has been an increased interest in the scientific community about the role of arginine in the short and long-term settings of the disease. We aim to conduct a systematic review of the clinical use of arginine in the management of MELAS and explore the role of arginine in the pathophysiology of the disease. We used PubMed advanced-strategy searches and only included full-text clinical trials on humans written in the English language. After applying the inclusion/exclusion criteria, four clinical trials were reviewed. We used the Meta-analysis of Observational Studies in Epidemiology (MOOSE) guidelines and Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) protocol for this systematic review. We used the Cochrane Collaboration risk-of-bias tool to assess the bias encountered in each study. Overall, IV arginine seems to be effective in improving symptoms during acute attacks of MELAS, while oral arginine supplementation increases endothelial function, preventing further stroke-like episodes.

PGC-1α activity and mitochondrial dysfunction in preterm infants

Extremely low gestational age neonates (ELGANs) are born in a relatively hyperoxic environment with weak antioxidant defenses, placing them at high risk for mitochondrial dysfunction affecting multiple organ systems including the nervous, respiratory, ocular, and gastrointestinal systems. The brain and lungs are highly affected by mitochondrial dysfunction and dysregulation in the neonate, causing white matter injury (WMI) and bronchopulmonary dysplasia (BPD), respectively. Adequate mitochondrial function is important in providing sufficient energy for organ development as it relates to alveolarization and axonal myelination and decreasing oxidative stress via reactive oxygen species (ROS) and reactive nitrogen species (RNS) detoxification. Peroxisome proliferator-activated receptor gamma coactivator-1 alpha (PGC-1α) is a master regulator of mitochondrial biogenesis and function. Since mitochondrial dysfunction is at the root of WMI and BPD pathobiology, exploring therapies that can regulate PGC-1α activity may be beneficial. This review article describes several promising therapeutic agents that can mitigate mitochondrial dysfunction through direct and indirect activation and upregulation of the PGC-1α pathway. Metformin, resveratrol, omega 3 fatty acids, montelukast, L-citrulline, and adiponectin are promising candidates that require further pre-clinical and clinical studies to understand their efficacy in decreasing the burden of disease from WMI and BPD in preterm infants.

Functional characterization of nutraceuticals using spectral clustering: Centrality of caveolae-mediated endocytosis for management of nitric oxide and vitamin D deficiencies and atherosclerosis

It is well recognized that redox imbalance, nitric oxide (NO), and vitamin D deficiencies increase risk of cardiovascular, metabolic, and infectious diseases. However, clinical studies assessing efficacy of NO and vitamin D supplementation have failed to produce unambiguous efficacy outcomes suggesting that the understanding of the pharmacologies involved is incomplete. This raises the need for using systems pharmacology tools to better understand cause-effect relationships at biological systems levels. We describe the use of spectral clustering methodology to analyze protein network interactions affected by a complex nutraceutical, Cardio Miracle (CM), that contains arginine, citrulline, vitamin D, and antioxidants. This examination revealed that interactions between protein networks affected by these substances modulate functions of a network of protein complexes regulating caveolae-mediated endocytosis (CME), TGF beta activity, vitamin D efficacy and host defense systems. Identification of this regulatory scheme and the working of embedded reciprocal feedback loops has significant implications for treatment of vitamin D deficiencies, atherosclerosis, metabolic and infectious diseases such as COVID-19.

Momordica charantia Extract Confers Protection Against Hypertension in Dahl Salt-Sensitive Rats

Hypertension is one of the main factors of cardiovascular disease worldwide and is strongly related to the overall mortality. High salt intake is a major risk factors for hypertension. Identifying functional foods that can help prevent mechanistic abnormalities mediating salt-induced hypertension is an issue of considerable nutraceutical and scientific interest. Dietary Momordica charantia may be an alternative approach to avoid salt-induced hypertension. Dahl salt-sensitive (DSS) rats were used to determine whether Momordica charantia water extracts (ME) exerts anti-hypertensive effects in the present study. ME gavage could significantly prevented the increase of blood pressure, blood urea nitrogen, creatinine, and urine protein-to-creatinine ratio of DSS rats. Metabolomics analysis indicated that high-salt diet induced abnormal amino acid metabolism was related to nitric oxide (NO) deficiency, but ME gavage could upregulate the activities of nitric oxide synthase, aspartate aminotransferase, argininosuccinate lyase, argininosuccinate synthase and restore endogenous synthesis of arginine and NO. Meanwhile, renal function was improved after ME gavage. Citrulline, as one of the important component in ME, could attenuate salt-induced hypertension by increasing endogenous synthesis of arginine and NO. Antioxidants in ME, such as phenolic compound, may avoid high-salt induced oxidative stress in DSS rats, which may be another mechanism by which ME prevented blood pressure increase. Thus, the present study indicated that feeding Momordica charantia could avoid high-salt-induced hypertension in DSS rats.

Subcutaneous Administration of a Nitric Oxide-Releasing Nanomatrix Gel Ameliorates Obesity and Insulin Resistance in High-Fat Diet-Induced Obese Mice

Nitric oxide (NO) is a gaseous signaling molecule, which plays crucial roles in various biological processes, including inflammatory responses, metabolism, cardiovascular functions, and cognitive function. NO bioavailability is reduced with aging and cardiometabolic disorders in humans and rodents. NO stimulates the metabolic rate by increasing the mitochondrial biogenesis and brown fat activation. Therefore, we propose a novel technology of providing exogenous NO to improve the metabolic rate and cognitive function by promoting the development of brown adipose tissue. In the present study, we demonstrate the effects of the peptide amphiphiles-NO-releasing nanomatrix gel (PANO gel) on high-fat diet-induced obesity, insulin resistance, and cognitive functions. Eight-week-old male C57BL/6 mice were subcutaneously injected in the brown fat area with the PANO gel or vehicle (PA gel) every 2 weeks for 12 weeks. The PANO gel-injected mice gained less body weight, improved glucose tolerance, and decreased fasting serum insulin and leptin levels compared with the PA gel-injected mice. Insulin signaling in the muscle, liver, and epididymal white adipose tissue was improved by the PANO gel injection. The PANO gel reduced inflammation, increased lipolysis in the epididymal white adipose tissue, and decreased serum lipids and liver triglycerides. Interestingly, the PANO gel stimulated uncoupled protein 1 gene expression in the brown and beige fat tissues. Furthermore, the PANO gel increased the cerebral blood flow and improved learning and memory abilities. Our results suggest that using the PANO gel to supply exogenous NO is a novel technology to treat metabolic disorders and cognitive dysfunctions.

Ornipural® Mitigates Malathion-Induced Hepato-Renal Damage in Rats via Amelioration of Oxidative Stress Biomarkers, Restoration of Antioxidant Activity, and Attenuation of Inflammatory Response

The current study was instigated by investigating the ameliorative potential of Ornipural^® solution against the hepato-renal toxicity of malathion. A total number of 35 male Wistar albino rats were divided equally into five groups. Group 1 served as control and received normal saline intraperitoneally. Group 2, the sham group, were administered only corn oil (vehicle of malathion) orally. Group 3 was orally intoxicated by malathion in corn oil at a dose of 135 mg/kg BW via intra-gastric gavage. Group 4 received malathion orally concomitantly with Ornipural^® intraperitoneally. Group 5 was given Ornipural^® solution in saline via intraperitoneal injection at a dose of (1 mL/kg BW). Animals received the treatment regime for 30 days. Histopathological examination revealed the harmful effect of malathion on hepatic and renal tissue. The results showed that malathion induced a significant decrease in body weight and marked elevation in the activity of liver enzymes, LDH, and ACP. In contrast, the activity of AchE and Paraoxonase was markedly decreased. Moreover, there was a significant increase in the serum content of bilirubin, cholesterol, and kidney injury markers. A significant elevation in malondialdehyde, nitric oxide (nitrite), and 8-hydroxy-2-deoxyguanosine was observed, along with a substantial reduction in antioxidant activity. Furthermore, malathion increased tumor necrosis factor-alpha, the upregulation of IL-1B, BAX, and IFN-β genes, and the downregulation of Nrf2, Bcl2, and HO-1 genes. Concurrent administration of Ornipural^® with malathion attenuated the detrimental impact of malathion through ameliorating metabolic biomarkers, restoring antioxidant activity, reducing the inflammatory response, and improving pathologic microscopic alterations. It could be concluded that Ornipural^® solution demonstrates hepatorenal defensive impacts against malathion toxicity at biochemical, antioxidants, molecular, and cellular levels.

Gut Microbiota and Metabolites in Atrial Fibrillation Patients and Their Changes after Catheter Ablation

The gut microbiota has been shown to be associated with multiple cardiovascular diseases, but there is little research on the gut microbiota and atrial fibrillation (AF); thus, how the gut microbiota and metabolites change in AF patients after catheter ablation is unclear. In this study, we used 16S rRNA high-throughput sequencing and nontargeted metabolomic detection to conduct horizontal and longitudinal analyses of the gut microbiota and metabolites of AF patients. Compared with a control group, species richness and diversity increased significantly in AF patients. Among them, opportunistic pathogenic bacteria, such as Klebsiella, Haemophilus, Streptococcus, and Enterococcus, were significantly increased, and symbiotic bacteria, such as Agathobacter and Butyrivibrio, were significantly reduced. After catheter ablation, intestinal symbiotic bacteria (Lactobacillus, Agathobacter, Lachnospira, etc.) were increased in most AF patients, while pathogenic bacteria (Ruminococcus, etc.) were reduced. Moreover, in AF patients, caffeine, which was negatively correlated with Klebsiella, was downregulated, and estradiol and ascorbic acid, which were positively correlated with Agathobacter, were also downregulated. After catheter ablation, citrulline, which was positively correlated with Ralstonia and Lactobacillus, was increased. Oleanolic acid, which was negatively correlated with Ralstonia was downregulated. In conclusion, our results not only show overall changes in the gut microbiota and metabolites in AF patients but also indicate their changes in the short term after catheter ablation. These data will provide novel possibilities for the future clinical diagnosis and treatment of AF.

IMPORTANCE Gut microbiota and metabolites play a very important role in human health and can not only assess human health but also treat and prevent diseases. We analyzed the characteristics of the microbiota and metabolites in the human gut and found the effect of disease on gut microbiota and metabolites, which may be of important value in the pathogenesis of atrial fibrillation. At the same time, we also observed dynamic changes in gut microbiota and metabolites with the intervention of catheter ablation, which was not available in previous studies.

Enzyme-Loaded Hemin/G-Quadruplex-Modified ZIF-90 Metal-Organic Framework Nanoparticles: Bioreactor Nanozymes for the Cascaded Oxidation of N-hydroxy-l-arginine and Sensing Applications

Biocatalytic cascades are challenging to operate in homogeneous solution, where diffusional mass transport hinders efficient communication between the reactive components. There is great interest in developing devices to perform such transformations in confined environments, which increase the efficiency of the cascaded process by generating high local concentrations of the reactive species. Herein, a bioreactor-nanozyme assembly is introduced for the cascaded aerobic oxidation of N-hydroxy-l-arginine (NOHA) to citrulline in the presence of glucose. The reaction mimics a key step in the nitric oxide synthase oxidation of l-arginine in nature. The system consists of glucose oxidase (GOx)-loaded hemin/G-quadruplex (hemin/G4)-modified ZIF-90 metal-organic framework nanoparticles. The aerobic oxidation of glucose by GOx yields H₂ O₂ that fuels the hemin/G4-catalyzed oxidation of NOHA into citrulline. The process driven by the bioreactor-nanozyme system is ≈sixfold enhanced compared to the homogeneous mixture of the biocatalysts, due to its operation in the confined environment of the nanoparticles. Extension to a three-step cascade is then demonstrated using a bioreactor composed of β-galactosidase/GOx-loaded hemin/G4-modified ZIF-90 nanoparticles activating the cascaded oxidation of NOHA to citrulline, in the presence of lactose. Moreover, the bioreactor-nanozyme hybrid is applied as a functional optical sensor of glucose, using fluorescence or chemiluminescence as readout signals.

Differential Metabolites and Metabolic Pathways Involved in Aerobic Exercise Improvement of Chronic Fatigue Symptoms in Adolescents Based on Gas Chromatography-Mass Spectrometry

Studies have found that the prevalence of chronic fatigue syndrome (CFS) in adolescents has continued to increase over the years, affecting learning and physical health. High school is a critical stage for adolescents to grow and mature. There are inadequate detection and rehabilitation methods for CFS due to an insufficient understanding of the physiological mechanisms of CFS. The purpose of this study was to evaluate the effect and metabolic mechanisms of an aerobic running intervention program for high school students with CFS. Forty-six male high school students with CFS were randomly assigned to the exercise intervention group (EI) and control group (CFS). Twenty-four age- and sex-matched healthy male students were recruited as healthy controls (HCs). The EI group received the aerobic intervention for 12 weeks, three times a week, in 45-min sessions; the CFS group maintained their daily routines as normal. The outcome measures included fatigue symptoms and oxidation levels. Keratin was extracted from the nails of all participants, and the oxidation level was assessed by measuring the content of 3-Nitrotyrosine (3-NT) in the keratin by ultraviolet spectrophotometry. All participants’ morning urine was collected to analyze urinary differential metabolites by the GC-MS technique before and after the intervention, and MetaboAnalyst 5.0 was used for pathway analysis. Compared with before the intervention, the fatigue score and 3-NT level in the EI group were significantly decreased after the intervention. The CFS group was screened for 20 differential metabolites involving the disruption of six metabolic pathways, including arginine biosynthesis, glycerolipid metabolism, pentose phosphate pathway, purine metabolism, β-alanine metabolism, and arginine and proline metabolism. After the intervention, 21 differential metabolites were screened, involved in alterations in three metabolic pathways: beta-alanine metabolism, pentose phosphate metabolism, and arginine and proline metabolism. Aerobic exercise was found to lessen fatigue symptoms and oxidative levels in students with CFS, which may be related to the regulation of putrescine (arginine and proline metabolism), 6-Phospho-D-Gluconate (starch and sucrose metabolism pathway), and Pentose (phosphate metabolism pathway).

L-citrulline ameliorates pathophysiology in a rat model of superimposed preeclampsia

BACKGROUND AND PURPOSE

Preeclampsia, characterized by hypertension, proteinuria, and fetal growth restriction, is one of the leading causes of maternal and perinatal mortality. By far, there is no effective pharmacological therapy for preeclampsia. The present study was conducted to investigate the effects of L-citrulline supplementation in Dahl salt-sensitive rat, a model of superimposed preeclampsia.

EXPERIMENTAL APPROACH

Parental DSSR were treated with L-citrulline (2.5 g/L in drinking water) from the day of mating to the end of lactation period. Blood pressure of the rats was monitored throughout pregnancy and markers of preeclampsia were assessed. Endothelial function of the pregnant DSSR was assessed by wire myograph.

KEY RESULTS

L-citrulline supplementation significantly reduced maternal blood pressure, proteinuria, and levels of circulating soluble fms-like tyrosine kinase 1 in DSSR. L-citrulline improved maternal endothelial function by augmenting the production of nitric oxide in the aorta and improving endothelium-derived hyperpolarizing factor-mediated vasorelaxation in resistance arteries. L-citrulline supplementation improved placental insufficiency and fetal growth, which were associated with an enhancement of angiogenesis and reduction of fibrosis and senescence in the placentas. In addition, L-citrulline downregulated genes involved in the toll-like receptor 4 and nuclear factor-κB signaling pathway.

CONCLUSION AND IMPLICATIONS

This study shows that L-citrulline supplementation reduces gestational hypertension, improves placentation and fetal growth in a rat model of superimposed preeclampsia. L-citrulline supplementation may represent an effective and safe therapeutic strategy for preeclampsia that benefit both the mother and the fetus.

Hepatic Ischemia-Reperfusion Impairs Blood-Brain Barrier Partly Due to Release of Arginase From Injured Liver

Aim: Hepatic ischemia-reperfusion (HIR) induces remote organs injury, including the brain. The homeostasis of the brain is maintained by the blood-brain barrier (BBB); thus, we aimed to investigate whether HIR impaired BBB and attempted to elucidate its underlying mechanism.

Methods: Cell viability of human cerebral microvascular endothelial cells (hCMEC/D3) was measured following 24 h incubation with a serum of HIR rat undergoing 1 h ischemia and 4 h reperfusion, liver homogenate, or lysate of primary hepatocytes of the rat. The liver homogenate was precipitated using (NH₄)₂SO₄ followed by separation on three columns and electrophoresis to identify the toxic molecule. Cell activity, apoptosis, proliferation, cell cycle, and expressions of proteins related to cell cycle were measured in hCMEC/D3 cells incubated with identified toxic molecules. HIR rats undergoing 1 h ischemia and 24 h reperfusion were developed to determine the release of an identified toxic molecule. BBB function was indexed as permeability to fluorescein and brain water. Endothelial cell proliferation and expressions of proteins related to the cell cycle in cerebral microvessels were measured by immunofluorescence and western blot.

Results: Toxic molecule to BBB in the liver was identified to be arginase. Arginase inhibitor nor-NOHA efficiently attenuated hCMEC/D3 damage caused by liver homogenate and serum of HIR rats. Both arginase and serum of HIR rats significantly lowered arginine (Arg) in the culture medium. Arg addition efficiently attenuated the impairment of hCMEC/D3 caused by arginase or Arg deficiency, demonstrating that arginase impaired hCMEC/D3 via depriving Arg. Both arginase and Arg deficiency damaged hCMEC/D3 cells by inhibiting cell proliferation, retarding the cell cycle to G1 phase, and downregulating expressions of cyclin A, cyclin D, CDK2, and CDK4. HIR notably increased plasma arginase activity and lowered Arg level, increased the BBB permeability accompanied with enhanced brain water, and decreased the proliferative cells (marked by Ki67) in cerebral microvessels (marked by CD31) and protein expressions of cyclin A, cyclin D, CDK2 and CDK4 in isolated brain microvessels. Oral supplement of Arg remarkably attenuated these HIR-induced alterations.

Conclusion: HIR leads to substantial release of arginase from the injured liver and then deprives systemic Arg. The Arg deficiency further impairs BBB via inhibiting the proliferation of brain microvascular endothelial cells by cell cycle arrest.

Citrulline, Biomarker of Enterocyte Functional Mass and Dietary Supplement. Metabolism, Transport, and Current Evidence for Clinical Use

L-Citrulline is a non-essential but still important amino acid that is released from enterocytes. Because plasma levels are reduced in case of impaired intestinal function, it has become a biomarker to monitor intestinal integrity. Moreover, oxidative stress induces protein citrullination, and antibodies against anti-citrullinated proteins are useful to monitor rheumatoid diseases. Citrullinated histones, however, may even predict a worse outcome in cancer patients. Supplementation of citrulline is better tolerated compared to arginine and might be useful to slightly improve muscle strength or protein balance. The following article shall provide an overview of L-citrulline properties and functions, as well as the current evidence for its use as a biomarker or as a therapeutic supplement.

NO, way to go: critical amino acids to replenish nitric oxide production in treating mucositis

PURPOSE OF REVIEW

There is still an unmet need for preventive and treatment strategies for chemotherapy-induced and radiotherapy-induced mucositis and its associated systemic inflammatory response (SIR) in cancer patients. Because of citrulline depletion due to cytotoxic therapy, nitric oxide (NO) production can be reduced, limiting its effect in many physiological processes. Restoring NO production could relieve mucositis severity by supporting host damage control mechanisms. Amino acids glutamine, arginine and citrulline are involved in NO production. This review including recent literature of preclinical and clinical studies will discuss the potential benefits of glutamine, arginine and citrulline on mucositis development with focus on NO production.

RECENT FINDINGS

Mucositis severity is more defined by host response to DNA damage than by DMA damage itself. Citrulline depletion because of afunctional enterocytes could be responsible for NO depletion during cytotoxic therapy. Restoring NO production during cytotoxic therapy could have a beneficial effect on mucositis development. Citrulline seems a more promising NO donor than glutamine or arginine during cytotoxic therapy, although clinical studies in mucositis patients are currently lacking.

SUMMARY

Glutamine, arginine and citrulline show in-vitro beneficial effects on inflammatory processes involved in mucositis. Translation to the clinic is difficult as demonstrated with use of glutamine and arginine. Citrulline, being the most potent NO donor with excellent oral bio-availability, is very promising as treatment choice for mucositis and its use deserves to be investigated in clinical trials with mucositis patients.

Neuroprotective Effects of Danshen Chuanxiongqin Injection Against Ischemic Stroke: Metabolomic Insights by UHPLC-Q-Orbitrap HRMS Analysis

The incidence of cerebral ischemic stroke characterized by high mortality is increasing every year. Danshen Chuanxiongqin Injection (DSCXQ), a traditional Chinese medicine (TCM) preparation, is often applied to treat cerebral apoplexy and its related sequelae. However, there is a lack of systematic research on how DSCXQ mediates its protective effects against cerebral ischemia stroke. Metabolomic analysis based on UHPLC-Q-Orbitrap HRMS was employed to explore the potential mechanisms of DSCXQ on ischemic stroke induced by transient middle cerebral artery occlusion (MCAO). Pattern analysis and metabolomic profiling, combined by multivariate analysis disclosed that 55 differential metabolites were identified between Sham group and Model group, involving sphingolipid metabolism, glycerophospholipid metabolism, phenylalanine, tyrosine and tryptophan biosynthesis, primary bile acid biosynthesis, pantothenate and CoA synthesis and valine, leucine and isoleucine biosynthesis pathways. DSCXQ could reverse brain metabolic deviations in stroke by significantly upregulating the levels of L-tryptophan, Lyso (18:0/0:0), LPC (18:2), Indole-3-methyl acetate, and downregulating the levels of sphinganine 1-phosphate, L-threonic acid, glutaconic acid and N6,N6,N6-Trimethyl-L-lysine. In our study, we focused on the neuroprotective effects of DSCXQ against neuroinflammatory responses and neuronal apoptosis on a stroke model based on sphingolipid metabolism. The expressions of Sphk1, S1PR1, CD62P, Bcl-2, Bax, and cleaved Caspase-3 in brain tissue were evaluated. The neurological deficit, cerebral infarct size and behavioral abnormality were estimated. Results showed that DSCXQ intervention significantly reduced cerebral infarct size, ameliorated behavioral abnormality, inhibited the expression of Sphk1, S1PR1, CD62P, Bax, Cleaved Caspase-3, while increased the level of Bcl-2, and prevented neuronal apoptosis. The limitations are that our study mainly focused on the verification of sphingolipid metabolism pathway in stroke, and while other metabolic pathways left unverified. Our study indicates that SphK1-SIP axis may potentiate neuroinflammatory responses and mediate brain damage through neuronal apoptosis, and DSCXQ could suppress the activity of SphK1-SIP axis to protect brain tissue in cerebral ischemia. In conclusion, this study facilitates our understanding of metabolic changes in ischemia stroke and the underlying mechanisms related to the clinical application of DSCXQ.

Nutraceutical, Dietary, and Lifestyle Options for Prevention and Treatment of Ventricular Hypertrophy and Heart Failure

Although well documented drug therapies are available for the management of ventricular hypertrophy (VH) and heart failure (HF), most patients nonetheless experience a downhill course, and further therapeutic measures are needed. Nutraceutical, dietary, and lifestyle measures may have particular merit in this regard, as they are currently available, relatively safe and inexpensive, and can lend themselves to primary prevention as well. A consideration of the pathogenic mechanisms underlying the VH/HF syndrome suggests that measures which control oxidative and endoplasmic reticulum (ER) stress, that support effective nitric oxide and hydrogen sulfide bioactivity, that prevent a reduction in cardiomyocyte pH, and that boost the production of protective hormones, such as fibroblast growth factor 21 (FGF21), while suppressing fibroblast growth factor 23 (FGF23) and marinobufagenin, may have utility for preventing and controlling this syndrome. Agents considered in this essay include phycocyanobilin, N-acetylcysteine, lipoic acid, ferulic acid, zinc, selenium, ubiquinol, astaxanthin, melatonin, tauroursodeoxycholic acid, berberine, citrulline, high-dose folate, cocoa flavanols, hawthorn extract, dietary nitrate, high-dose biotin, soy isoflavones, taurine, carnitine, magnesium orotate, EPA-rich fish oil, glycine, and copper. The potential advantages of whole-food plant-based diets, moderation in salt intake, avoidance of phosphate additives, and regular exercise training and sauna sessions are also discussed. There should be considerable scope for the development of functional foods and supplements which make it more convenient and affordable for patients to consume complementary combinations of the agents discussed here. Research Strategy: Key word searching of PubMed was employed to locate the research papers whose findings are cited in this essay.