Guanidinosuccinic Acid Research Articles

Integrating metabolomics and network toxicology to reveal the mechanism of hypoaconitine-induced hepatotoxicity in mice

Hypoaconitine (HA), a major secondary metabolite of aconite (a plant-derived rodenticide), is a highly toxic di-ester alkaloidal constituent. The toxicity of HA is intense with a low LD50. However, studies on its toxicity mechanism have mainly focused on cardiotoxicity, with few reports on the mechanism of hepatotoxicity. In this study, we combined metabolomics and network toxicology to investigate the effects of HA on the liver and analyzed the mechanisms by which it causes hepatotoxicity. The results of metabolomics studies indicated diethylphosphate, sphingosine-1-phosphate, glycerophosphorylcholine, 2,8-quinolinediol, guanidinosuccinic acid, and D-proline as differential metabolites after HA exposure. These metabolites are involved in eight metabolic pathways including arginine and proline metabolism, ether lipid metabolism, β-alanine metabolism, sphingolipid metabolism, glutathione metabolism, and glycerophospholipid metabolism. Network toxicology analysis of HA may affect the HIF-1 signaling pathway, IL-17 signaling pathway, PI3K-Akt signaling pathway, MAPK signaling pathway, and so on by regulating the targets of ALB, HSP90AA1, MMP9, CASP3, and so on. Integrating the results of metabolomics and network toxicology, it was concluded that HA may induce hepatotoxicity by triggering physiological processes such as oxidative stress, inflammatory response, and inducing apoptosis in hepatocytes.

An Overview on Naturally Occurring Phytoconstituent: Lithospermic Acid

Abstract: Lithospermic acid is a phenylpropanoid oligomer isolated from an aqueous extract of dried roots of various Lamiaceae and Boraginaceae plants and used as a folk medicine to treat cardiovascular disease and to improve body functions. The manuscript has been written to provide valuable insights into naturally occurring phytocomponent, Lithospermic acid, and even explore its therapeutic potential. The data have been gathered from books and web sources, including Science Direct, Publons, Web of Science, and Scopus of the latest year. Lithospermic acid is a conjugate of rosmarinic and caffeic acid with a dihydro benzofuran nucleus and possesses a high antioxidant potential and prevents the production of superoxide radicals and lipid peroxidation and protects the tissue from deleterious effects of reactive oxygen species. In addition, it also possesses a wide range of pharmacological activities, including reducing atherosclerosis, anti-inflammatory, hepatoprotective, anti-viral, HIV-1 integrase, and hyaluronidase inhibition, aldose reductase inhibition and improvement in uremic symptoms guanidino succinic acid level. Due to its anti-HIV activity, LA has gained much attention among the scientific community. Moreover, it is widely distributed to all the peripheral tissue in rats, and its metabolites undergo enterohepatic circulation and are excreted through biliary excretion. In this review, we concluded LA with its phytochemistry, pharmacokinetics, and pharmacological activities.

Effects of Shenling Baizhu powder on pyrotinib-induced diarrhea: analysis of gut microbiota, metabonomics, and network pharmacology

BackgroundShenling Baizhu Powder (SBP) is a traditional Chinese medicine (TCM) prescription, which has the good efficacy on gastrointestinal toxicity. In this study, we used gut microbiota analysis, metabonomics and network pharmacology to investigate the therapeutic effect of SBP on pyrotinib-induced diarrhea.Methods24 Rats were randomly divided into 4 groups: control group, SBP group (3.6 g/kg /bid SBP for 10 days), pyrotinib model group (80 mg/kg/qd pyrotinib) and pyrotinib + SBP treatment group. A 16S rRNA sequencing was used to detect the microbiome of rat fecal bowel. Metabolic profiles were collected by non-targeted metabolomics and key metabolic pathways were identified using MetaboAnalyst 5.0. The antitumor effect of SBP on cells treated with pyrotinib was measured using a CCK-8 assay. Network pharmacology was used to predict the target and action pathway of SBP in treating pyrotinib-related diarrhea.ResultsIn vivo study indicated that SBP could significantly alleviate pyrotinib-induced diarrhea, reaching a therapeutic effect of 66.7%. SBP could regulate pyrotinib-induced microbiota disorder. LEfSe research revealed that the SBP could potentially decrease the relative abundance of Escherichia, Helicobacter and Enterobacteriaceae and increase the relative abundance of Lachnospiraceae, Bacilli, Lactobacillales etc. In addition, 25-Hydroxycholesterol, Guanidinosuccinic acid, 5-Hydroxyindolepyruvate and cAMP were selected as potential biomarkers of SBP for pyrotinib-induced diarrhea. Moreover, Spearman's analysis showed a correlation between gut microbiota and metabolite: the decreased 25-hydroxycholesterol in the pyrotinib + SBP treatment group was negatively correlated with Lachnospiraceae while positively correlated with Escherichia and Helicobacter. Meanwhile, SBP did not affect the inhibitory effect of pyrotinib on BT-474 cells and Calu-3 cells in vitro. Also, the network analysis further revealed that SBP treated pyrotinib-induced diarrhea through multiple pathways, including inflammatory bowel disease, IL-17 signaling pathway, pathogenic Escherichia coli infection and cAMP signaling pathway.ConclusionsSBP could effectively relieve pyrotinib-induced diarrhea, revealing that intestinal flora and its metabolites may be involved in this process.

Pathogenesis of ventilator-induced lung injury: metabolomics analysis of the lung and plasma.

Nowadays,the mechanical ventilation (MV) aims to rest the respiratory muscles while providing adequate gas exchange, and it has been a part of basic life support during general anesthesia as well as in critically ill patients with and without respiratory failure. However, MV itself has the potential to cause or worsen lung injury, which is also known as ventilator-induced lung injury (VILI). Thus, the early diagnosis of VILI is of great importance for the prevention and treatment of VILI. This study aimed to investigate the metabolomes in the lung and plasma of mice receiving mechanical ventilation (MV). Healthy mice were randomly assigned into control group; (2) high volume tidal (HV) group (30 ml/kg); (3) low volume tidal (LV) group (6 ml/kg). After ventilation for 4h, mice were sacrificed and the lung tissue and plasma were collected. The lung and plasma were processed for the metabolomics analysis. We also performed histopathological examination on the lung tissue. We detected moderate inflammatory damage with alveolar septal thickening in the HV group compared with the normal and LV groups.The metabolomics analysis results showed MV altered the metabolism which was characterized by the dysregulation of γ-amino butyric acid (GABA) system and urea cycle (desregulations in plasma and lung guanidinosuccinic acid, argininosuccinic acid, succinic acid semialdehyde and lung GABA ), Disturbance of citric acid cycle (CAC) (increased plasma glutamine and lung phosphoenol pyruvate) and redox imbalance (desregulations in plasma and/or lung ascorbic acid, chenodeoxycholic acid, uric acid, oleic acid, stearidonic acid, palmitoleic acid and docosahexaenoic acid). Moreover, the lung and plasma metabolomes were also significantly different between LV and HV groups. Some lung and plasma metabolites related to the GABA system and urea cycle, citric acid cycle and redox balance were significantly altered, and they may be employed for the evaluation of VILI and serve as targets in the treatment of VILI.

Metabolomics study of fibroblasts damaged by UVB and BaP

We have recently shown that both UVB and BaP can induce the production of ROS, apoptosis and even cancer. However, the differences in the metabolic profiles of skin damaged by UVB, BaP or UVB combined with BaP have not been studied. Therefore, we examined the metabolic changes in the human foreskin fibroblast injured by UVB or BaP or the combination of the two, using ultra performance liquid chromatography (UPLC) coupled with quadrupole time-of-flight mass spectrometry (qTOF-MS). 24 metabolites were altered in the UVB damage group, 25 in the BaP damage group, and 33 in the UVB combined with BaP group. These alterations indicated that the metabolic mechanisms of HFF-1 cells treated with UVB or BaP are related to multiple main metabolites including glycerophosphocholine (PC), lactosylceramide (LacCer), guanidinosuccinic acid (GSA), glutathione(GSH), and lysophosphatidylcholine (LysoPC) and the main mechanisms involved glycerophospholipid and glutathione metabolism. Thus, our report provided useful insight into the underlying mechanisms of UVB and BaP damage to skin cells.

Capillary Electrophoresis Mass Spectrometry-Based Metabolomics of Plasma Samples from Healthy Subjects in a Cross-Sectional Japanese Population Study.

For large-scale metabolomics, such as in cohort studies, normalization protocols using quality control (QC) samples have been established when using data from gas chromatography and liquid chromatography coupled to mass spectrometry. However, normalization protocols have not been established for capillary electrophoresis–mass spectrometry metabolomics. In this study, we performed metabolome analysis of 314 human plasma samples using capillary electrophoresis–mass spectrometry. QC samples were analyzed every 10 samples. The results of principal component analysis for the metabolome data from only the QC samples showed variations caused by capillary replacement in the first principal component score and linear variation with continuous measurement in the second principal component score. Correlation analysis between diagnostic blood tests and plasma metabolites normalized by the QC samples was performed for samples from 188 healthy subjects who participated in a Japanese population study. Five highly correlated pairs were identified, including two previously unidentified pairs in normal healthy subjects of blood urea nitrogen and guanidinosuccinic acid, and gamma-glutamyl transferase and cysteine glutathione disulfide. These results confirmed the validity of normalization protocols in capillary electrophoresis–mass spectrometry using large-scale metabolomics and comprehensive analysis.

Photoperiodic changes in hippocampal neurogenesis and plasma metabolomic profiles in relation to depression-like behavior in mice

Photoperiod alters affective behaviors and brain neuroplasticity in several mammalian species. We addressed whether neurogenesis and signaling pathways of insulin-like growth factor-I (IGF-I), a key modulator of neuroplasticity, are regulated by photoperiod in C57BL/6 J mice, a putative model of seasonal affective disorder. We also examined the effects of photoperiod on plasma metabolomic profiles in relation to depression-like behavior to understand a possible linkage between peripheral metabolism and behavior. Mice that were maintained under long-day conditions (LD) exhibited a higher number of 5-bromo-2′-deoxyuridine-positive cells and higher levels of astrocyte marker in the dentate gyrus of the hippocampus compared to that of mice under short-day conditions (SD). Plasma IGF-I levels and levels/expression of IGF-I signaling molecules in the hippocampus (Brn-4, NeuroD1, and phospho-Akt) involved in neuronal proliferation and differentiation were higher in the mice under LD. Metabolome analysis using plasma of the mice under LD and SD identified several metabolites that were highly correlated with immobility in the forced swim test, a depression-like behavior. Negative correlations with behavior occurred in the levels of 23 metabolites, including metabolites related to neurogenesis and antidepressant-like effects of exercise, metabolites in the biosynthesis of arginine, and the occurrence of branched chain amino acids. Three metabolites had positive correlations with the behavior, including guanidinosuccinic acid, a neurotoxin. Taken together, photoperiodic responses of neurogenesis and neuro-glial organization in the hippocampus may be involved in photoperiodic alteration of depression-like behavior, mediated through multiple pathways, including IGF-I and peripheral metabolites.

Uremic Toxins Affecting Cardiovascular Calcification: A Systematic Review.

Cardiovascular calcification is highly prevalent and associated with increased morbidity in chronic kidney disease (CKD). This review examines the impact of uremic toxins, which accumulate in CKD due to a failing kidney function, on cardiovascular calcification. A systematic literature search identified 41 uremic toxins that have been studied in relation to cardiovascular calcification. For 29 substances, a potentially causal role in cardiovascular calcification was addressed in in vitro or animal studies. A calcification-inducing effect was revealed for 16 substances, whereas for three uremic toxins, namely the guanidino compounds asymmetric and symmetric dimethylarginine, as well as guanidinosuccinic acid, a calcification inhibitory effect was identified in vitro. At a mechanistic level, effects of uremic toxins on calcification could be linked to the induction of inflammation or oxidative stress, smooth muscle cell osteogenic transdifferentiation and/or apoptosis, or alkaline phosphatase activity. For all middle molecular weight and protein-bound uremic toxins that were found to affect cardiovascular calcification, an increasing effect on calcification was revealed, supporting the need to focus on an increased removal efficiency of these uremic toxin classes in dialysis. In conclusion, of all uremic toxins studied with respect to calcification regulatory effects to date, more uremic toxins promote rather than reduce cardiovascular calcification processes. Additionally, it highlights that only a relatively small part of uremic toxins has been screened for effects on calcification, supporting further investigation of uremic toxins, as well as of associated post-translational modifications, on cardiovascular calcification processes.

Metabolomics analysis of the effects of quercetin on renal toxicity induced by cadmium exposure in rats.

This study aims to explore the protective effects of quercetin against cadmium-induced nephrotoxicity utilizing metabolomics methods. Male Sprague-Dawley rats were randomly assigned to six groups: control, different dosages of quercetin (10 and 50mg/kg·bw, respectively), CdCl2 (4.89mg/kg·bw) and different dosages quercetin plus CdCl2 groups. After 12weeks, the kidneys were collected for metabolomics analysis and histopathology examination. In total, 11 metabolites were confirmed, the intensities of which significantly changed (up-regulated or down-regulated) compared with the control group (p < 0.00067). These metabolites include xanthosine, uric acid (UA), guanidinosuccinic acid (GSA), hypoxanthine (Hyp), 12-hydroxyeicosatetraenoic acid (tetranor 12-HETE), taurocholic acid (TCA), hydroxyphenylacetylglycine (HPAG), deoxyinosine (DI), ATP, formiminoglutamic acid (FIGLU) and arachidonic acid (AA). When high-dose quercetin and cadmium were given to rats concurrently, the intensities of above metabolites significantly restored (p < 0.0033 or p < 0.00067). The results showed quercetin attenuated Cd-induced nephrotoxicity by regulating the metabolism of lipids, amino acids, and purine, inhibiting oxidative stress, and protecting kidney functions.

Effects of quercetin on cadmium-induced toxicity in rat urine using metabonomics techniques.

This study aimed to analyse the protective effects of quercetin on the toxicity of cadmium (Cd) using metabonomics techniques. Sixty male Sprague-Dawley rats were randomly divided into six groups (n = 10): control group (C), low-dose quercetin-treated group (Q1; 10 mg/kg bw/day), high-dose quercetin-treated group (Q2; 50 mg/kg bw/day), Cd-treated group (D; 4.89 mg/kg bw/day), low-dose quercetin plus Cd-treated group (DQ1) and high-dose quercetin plus Cd-treated group (DQ2). The rats continuously received quercetin and Cd via gavage and drinking water for 12 weeks, respectively. The rat urine samples were collected for metabonomics analysis. Finally, 10 metabolites were identified via the metabonomics profiles of the rat urine samples. Compared with the control group, the intensities of taurine, phosphocreatine, l-carnitine and uric acid were significantly decreased (p < 0.01) and those of LysoPC (18: 2 (9Z, 12Z)), guanidinosuccinic acid, dopamine, 2,5,7,8-tetramethyl-2(2'-carboxyethyl)-6-hydroxychroman and allantoic acid were significantly increased (p < 0.01) in the Cd-treated group. However, the intensities of the aforementioned metabolites had restorative changes in the high-dose quercetin plus Cd-treated groups unlike those in Cd-treated group (p < 0.01 or p < 0.05). Results indicated that quercetin exerts protective effects on Cd-induced toxicity by regulating energy and lipid metabolism, enhancing the antioxidant defence system and protecting liver and kidney function and so on.

Metabolic profiles of serum samples from ground glass opacity represent potential diagnostic biomarkers for lung cancer

Lung cancer is a leading cause of cancer deaths worldwide. Low-dose computed tomography (LDCT) screening trials indicated that LDCT is effective for the early detection of lung cancer, but the findings were accompanied by high false positive rates. Therefore, the detection of lung cancer needs complementary blood biomarker tests to reduce false positive rates. In order to evaluate the potential of metabolite biomarkers for diagnosing lung cancer and increasing the effectiveness of clinical interventions, serum samples from subjects participating in a low-dose CT-scan screening were analyzed by using untargeted liquid chromatography-hybrid quadrupole time-of-flight mass spectrometry (LC-Q-TOF-MS). Samples were acquired from 34 lung patients with ground glass opacity diagnosed lung cancer and 39 healthy controls. In total, we identified 9 metabolites in electron spray ionization (ESI)(+) mode and 7 metabolites in ESI(-) mode. L-(+)-gulose, phosphatidylethanolamine (PE)(22:2(13Z,16Z)/15:0), cysteinyl-glutamine, S-japonin, threoninyl-glutamine, chlorate, 3-oxoadipic acid, dukunolide A, and malonic semialdehyde levels were observed to be elevated in serum samples of lung cancer cases when compared to those of healthy controls. By contrast, 1-(2-furanylmethyl)-1H-pyrrole, 2,4-dihydroxybenzoic acid, monoethyl carbonate, guanidinosuccinic acid, pseudouridine, DIMBOA-Glc, and 4-feruloyl-1,5-quinolactone levels were lower in serum samples of lung cancer cases compared with those of healthy controls. This study demonstrates evidence of early metabolic alterations that can possibly distinguish malignant ground glass opacity from benign ground glass opacity. Further studies in larger pools of samples are warranted.

Argininosuccinate neurotoxicity and prevention by creatine in argininosuccinate lyase deficiency: An in vitro study in rat three-dimensional organotypic brain cell cultures.

The urea cycle disorder (UCD) argininosuccinate lyase (ASL) deficiency, caused by a defective ASL enzyme, exhibits a wide range of phenotypes, from life-threatening neonatal hyperammonemia to asymptomatic patients, with only the biochemical marker argininosuccinic acid (ASA) elevated in body fluids. Remarkably, even without ever suffering from hyperammonemia, patients often develop severe cognitive impairment and seizures. The goal of this study was to understand the effect on the known toxic metabolite ASA and the assumed toxic metabolite guanidinosuccinic acid (GSA) on developing brain cells, and to evaluate the potential role of creatine (Cr) supplementation, as it was described protective for brain cells exposed to ammonia. We used an in vitro model, in which we exposed three-dimensional (3D) organotypic rat brain cell cultures in aggregates to different combinations of the metabolites of interest at two time points (representing two different developmental stages). After harvest and cryopreservation of the cell cultures, the samples were analyzed mainly by metabolite analysis, immunohistochemistry, and western blotting. ASA and GSA were found toxic for astrocytes and neurons. This toxicity could be reverted in vitro by Cr. As well, an antiapoptotic effect of ASA was revealed, which could contribute to the neurotoxicity in ASL deficiency. Further studies in human ASL deficiency will be required to understand the biochemical situation in the brain of affected patients, and to investigate the impact of high or low arginine doses on brain Cr availability. In addition, clinical trials to evaluate the beneficial effect of Cr supplementation in ASL deficiency would be valuable.

Metabonomics analysis of kidneys in rats administered with chronic low-dose cadmium by ultra-performance liquid chromatography-mass spectrometry.

This study aimed to investigate the nephrotoxicity in rats administered with chronic low-dose cadmium (Cd) by ultra-performance liquid chromatography-mass spectrometry. A total of 40 male Sprague-Dawley rats were randomly assigned to four groups, namely: control; low-dose (0.13mg/kg·body weight [bw]); middle-dose (0.80mg/kg·bw); and high-dose (4.89mg/kg·bw). The rats received CdCl2 daily via drinking water for 24weeks. Rat kidneys were collected for metabonomics analysis. Principal components analysis and partial least-squares discriminant analysis were used to investigate the metabonomics profile changes in the kidney samples and to screen the potential biomarkers. Ten metabolites were identified in the positive and negative ion modes. Compared with the control group, the intensities of tetranor 12-HETE, uric acid, hypoxanthine, phenylacetylglycine, guanidinosuccinic acid and xanthosine significantly increased (P<0.01), and those of imidazolelactic acid, lactose 6-phosphate, l-urobilinogen and arachidonic acid significantly decreased (P<0.01) in the high-dose group. Results showed that exposure to Cd in rats induced oxidative stress to the kidneys and disrupted amino acid metabolism, fatty acid metabolism and energy metabolism.

Metabolomics for the Effect of Biotin and Nicotinamide on Transition Dairy Cows.

The objective of this study was to evaluate alterations in serum metabolites of transition dairy cows affected by biotin (BIO) and nicotinamide (NAM) supplementation. A total of 40 multiparous Holsteins were paired and assigned randomly within a block to one of the following four treatments: control (T0), 30 mg/day BIO (TB), 45 g/day NAM (TN), and 30 mg/day BIO + 45 g/day NAM (TB+N). Supplemental BIO and NAM were drenched on cows from 14 days before the expected calving date. Gas chromatography time-of-flight/mass spectrometry was used to analyze serum samples collected from eight cows in every groups at 14 days after calving. In comparison to T0, TB, TN, and TB+N had higher serum glucose concentrations, while non-esterified fatty acid in TN and TB+N and triglyceride in TB+N were lower. Adenosine 5'-triphosphate was significantly increased in TB+N. Both TN and TB+N had higher glutathione and lower reactive oxygen species. Moreover, TB significantly increased inosine and guanosine concentrations, decreased β-alanine, etc. Certain fatty acid concentrations (including linoleic acid, oleic acid, etc.) were significantly decreased in both TN and TB+N. Some amino acid derivatives (spermidine in TN, putrescine and 4-hydroxyphenylethanol in TB+N, and guanidinosuccinic acid in both TN and TB+N) were affected. Correlation network analysis revealed that the metabolites altered by NAM supplementation were more complicated than those by BIO supplementation. These findings showed that both BIO and NAM supplementation enhanced amino acid metabolism and NAM supplementation altered biosynthesis of unsaturated fatty acid metabolism. The improved oxidative status and glutathione metabolism further indicated the effect of NAM on oxidative stress alleviation.

Metabolomic analysis of the toxic effect of chronic exposure of cadmium on rat urine

This study aimed to assess the toxic effect of chronic exposure to cadmium through a metabolomic approach based on ultra-performance liquid chromatography/mass spectrometry (UPLC-MS). Forty male Sprague-Dawley rats were randomly assigned to the following groups: control, low-dose cadmium chloride (CdCl2) (0.13mg/kg body weight (bw)), middle-dose CdCl2 (0.8/kgbw), and high-dose CdCl2 (4.9mg/kgbw). The rats continuously received CdCl2 via drinking water for 24weeks. Rat urine samples were then collected at different time points to establish the metabolomic profiles. Multiple statistical analyses with principal component analysis and partial least squares-discriminant analysis were used to investigate the metabolomic profile changes in the urine samples and screen for potential biomarkers. Thirteen metabolites were identified from the metabolomic profiles of rat urine after treatment. Compared with the control group, the treated groups showed significantly increased intensities of phenylacetylglycine, guanidinosuccinic acid, 4-pyridoxic acid, 4-aminohippuric acid, 4-guanidinobutanoic acid, allantoic acid, dopamine, LysoPC(18:2(9Z,12Z)), and L-urobilinogen. By contrast, the intensities of creatinine, L-carnitine, taurine, and pantothenic acid in the treated groups were significantly decreased. These results indicated that Cd disrupts energy and lipid metabolism. Meanwhile, Cd causes liver and kidney damage via induction of oxidative stress; serum biochemical indices (e.g., creatinine and urea nitrogen) also support the aforementioned results.

Application of Metabolic Profiling to Abdominal Aortic Aneurysm Research.

Abdominal aortic aneurysm (AAA) is a complex disease posing diagnostic and therapeutic challenges. Metabonomics may aid in the diagnosis of AAA, determination of individualized risk, discovery of therapeutic targets, and improve understanding of pathogenesis. A systematic review of the diversity and outcomes of existing AAA metabonomic research has been performed. Original research studies applying metabonomics to human aneurysmal disease are included. Seven relevant articles were identified: four studies were based on plasma/serum metabolite profiling, and three studies examined aneurysmal tissue. Aminomalonic acid, guanidinosuccinic acid, and glycerol emerge as potential plasma biomarkers of large aneurysm. Lipid profiling improves predictive models of aneurysm presence. Patterns of metabolite variation associated with AAA relate to carbohydrate and lipid metabolism. Perioperative perturbations in metabolites suggest differential systemic inflammatory responses to surgery, generating hypotheses for adjunctive perioperative therapy. Significant limitations include small study sizes, lack of correction for multiple testing false discovery rates, and single time-point sampling. Metabolic profiling carries the potential to identify biomarkers of AAA and elucidate pathways underlying aneurysmal disease. Statistically and methodologically robust studies are required for validation, addressing the hiatus in understanding mechanisms of aneurysm growth and developing effective treatment strategies.

Quantitative analysis of biomarkers of liver and kidney injury in serum and urine using ultra-fast liquid chromatography with tandem mass spectrometry coupled with a hydrophilic interaction chromatography column: Application to monitor injury induced by Euphorbiae pekinensis Radix.

Fast and sensitive monitoring of drug-induced liver and kidney injury in early stage is beneficial. An ultrafast liquid chromatography with tandem mass spectrometry assay was developed and validated to simultaneously determine ten endogenous biomarkers in serum and urine, including hippuric acid, phenylacetylglycine, 5-oxoproline, cholic acid, taurine, indoleacetic acid, 3-indoxyl sulfate, guanidinosuccinic acid, guanidinoacetic acid and uric acid. A CAPCELL CORE PC column (2.1 × 150 mm, 2.7 μm) was adopted for analytes separation. Gradient elution was performed with acetonitrile and water containing 5 mM ammonium acetate. Simple protein precipitation was applied in sample preparation. Good linearities were achieved with all the regression coefficients above 0.9911. Accuracy was 2.9-14.2% in serum and 4.1-14.6% in urine. The mean recovery was above 70% with acceptable matrix effects. The method was applied to monitor injury induced by Euphorbiae pekinensis Radix with a subacute rats model. All the biomarkers showed obvious concentration changes during the injury period. Furthermore, several biomarkers showed significant changes in earlier stage when compared with the current clinical serum bio-parameters. The method might be helpful for early diagnosis of drug induced liver and kidney injury in clinical after tested on more drugs.

Improved Gas Chromatographic Determination of Guanidino Compounds Using Isovaleroylacetone and Ethyl Chloroformate as Derivatizing Reagents.

An improved GC method in terms of sensitivity and decrease in the analysis time has been developed for the analysis of eight guanidino compounds: guanidine (G), methylguanidine (MG), creatinine (CTN), guanidinoacetic acid (GAA), guanidinobutyric acid (GBA), guanidinopropionic acid (GPA), argenine (Arg), and guanidinosuccinic acid (GSA), using isovaleroylacetone (IVA) and ethyl chloroformate (ECF) as derivatizing reagents. The separation was obtained from column HP-5 (30 m × 0.32 mm i.d.) with film thickness of 0.25 μm within 11 min. The linear calibrations were obtained with 0.5 to 50 μg/mL with coefficient of determination (R(2)) within 0.9969 - 0.9998. Limits of detections (LODs) were within 5 - 140 ng/mL. The derivatization, separation and determination was repeatable (n = 6) with relative standard deviation (RSD) within 1.2 - 3.1%. The guanidino compounds were determined in deproteinized serum of healthy volunteers and uremic patients within below LOD to 8.8 μg/mL and below LOD to 43.99 μg/mL with RSD within 1.4 - 3.6%. The recovery of guanidino compounds calculated by standard addition from serum was within 96.1 - 98.9%, with RSD 1.4 - 3.6%.

Determination of 12 potential nephrotoxicity biomarkers in rat serum and urine by liquid chromatography with mass spectrometry and its application to renal failure induced bySemen Strychni

In previous nephrotoxicity metabonomic studies, several potential biomarkers were found and evaluated. To investigate the relationship between the nephrotoxicity biomarkers and the therapeutic role of Radix Glycyrrhizae extract on Semen Strychni-induced renal failure, 12 typical biomarkers are selected and a simple LC-MS method has been developed and validated. Citric acid, guanidinosuccinic acid, taurine, guanidinoacetic acid, uric acid, creatinine, hippuric acid, xanthurenic acid, kynurenic acid, 3-indoxyl sulfate, indole-3-acetic acid, and phenaceturic acid were separated by a Phenomenex Luna C18 column and a methanol/water (5 mM ammonium acetate) gradient program with a runtime of 20 min. The prepared calibration curves showed good linearity with regression coefficients all above 0.9913. The absolute recoveries of analytes from serum and urine were all more than 70.4%. With the developed method, analytes were successfully determined in serum and urine samples within 52 days. Results showed that guanidinosuccinic acid, guanidinoacetic acid, 3-indoxyl sulfate, and indole-3-acetic acid (only in urine) were more sensitive than the conventional renal function markers in evaluating the therapeutic role of Radix Glycyrrhizae extract on Semen Strychni-induced renal failure. The method could be further used in predicting and monitoring renal failure cause by other reasons in the following researches.

Pharmacokinetics of Guanidinosuccinic Acid in Rat Blood and Cerebrospinal Fluid

Guanidinosuccinic acid (GSA) is a uremic toxin, and its excess accumulation in the CSF under uremic conditions is thought to produce neural excitotoxicity. It is important to understand the manner of GSA distribution/elimination from the circulating blood and CSF and its alteration in the presence of renal failure. The purpose of this study was to evaluate the kinetics of GSA in the circulating blood using a rat model of cisplatin-induced renal failure and GSA transport between the circulating blood and CSF. The AUCinf and t1/2 of GSA in cisplatin-treated rats were approximately 7-fold greater than those in normal rats. The CLtot of GSA in cisplatin-treated rats was reduced by 88% compared with normal rats, whereas the Vss of GSA did not differ between normal and cisplatin-treated rats. These results suggest that the renal elimination of GSA is attenuated in cisplatin-treated rats. In normal rats, the elimination clearance of GSA from the CSF (15.5 µL/(min·rat)) was found to be 88-fold greater than its blood-to-CSF influx clearance (0.176 µL/(min·rat)). Thus, the greater elimination clearance of GSA from the CSF, compared with the influx clearance, may contribute to the maintenance of a low GSA concentration in the CSF.