Increased serum bile acid concentration following low-dose chronic administration of thioacetamide in rats, as evidenced by metabolomic analysis

Cyclosporine A-induced systemic metabolic perturbations in rats: A comprehensive metabolome analysis

A better understanding of cyclosporine A (CsA)-induced nephro- and hepatotoxicity at the molecular level is necessary for safe and effective use. Utilizing a sophisticated study design, this study explored metabolic alterations after long-term CsA treatment in vivo. Rats were exposed to CsA with 4, 10, and 25 mg/kg for 4 weeks and then sacrificed to obtain liver, kidney, urine, and serum for untargeted metabolomics analysis. Differential network analysis was conducted to explore the biological relevance of metabolites significantly altered by toxicity-induced disturbance. Dose-dependent toxicity was observed in all biospecimens. The toxic effects were characterized by alterations of metabolites related to energy metabolism and cellular membrane composition, which could lead to the cholestasis-induced accumulation of bile acids in the tissues. The unfavorable impacts were also demonstrated in the serum and urine. Intriguingly, phenylacetylglycine was increased in the kidney, urine, and serum treated with high doses versus controls. Differential correlation network analysis revealed the strong correlations of deoxycytidine and guanosine with other metabolites in the network, which highlighted the influence of repeated CsA exposure on DNA synthesis. Overall, prolonged CsA administration had system-level dose-dependent effects on the metabolome in treated rats, suggesting the need for careful usage and dose adjustment.

Metabolomic Analysis of Pediatric Patients with Idiosyncratic Drug-Induced Liver Injury According to the Updated RUCAM

Hepatotoxicity, a common adverse drug effect, has been extensively studied in adult patients. However, it is equally important to investigate this condition in pediatric patients to develop personalized treatment strategies for children. This study aimed to identify plasma biomarkers that characterize hepatotoxicity in pediatric patients through an observational case-control study. Metabolomic analysis was conducted on 55 pediatric patients with xenobiotic liver toxicity and 88 healthy controls. The results revealed clear differences between the two groups. Several metabolites, including hydroxydecanoylcarnitine, octanoylcarnitine, lysophosphatidylcholine, glycocholic acid, and taurocholic acid, were identified as potential biomarkers (area under the curve: 0.817; 95% confidence interval: 0.696-0.913). Pathway analysis indicated involvement of primary bile acid biosynthesis and the metabolism of taurine and hypotaurine (p < 0.05). The findings from untargeted metabolomic analysis demonstrated an increase in bile acids in children with hepatotoxicity. The accumulation of cytotoxic bile acids should be further investigated to elucidate the role of these metabolites in drug-induced liver injury.

Pathway-level multi-omics analysis of the molecular mechanisms underlying the toxicity of long-term tacrolimus exposure

Tacrolimus (TAC)-based treatment is associated with nephrotoxicity and hepatotoxicity; however, the underlying molecular mechanisms responsible for this toxicity have not been fully explored. This study elucidated the molecular processes underlying the toxic effects of TAC using an integrative omics approach. Rats were sacrificed after 4 weeks of daily oral TAC administration at a dose of 5 mg/kg. The liver and kidney underwent genome-wide gene expression profiling and untargeted metabolomics assays. Molecular alterations were identified using individual data profiling modalities and further characterized by pathway-level transcriptomics-metabolomics integration analysis. Metabolic disturbances were mainly related to an imbalance in oxidant-antioxidant status, as well as in lipid and amino acid metabolism in the liver and kidney. Gene expression profiles also indicated profound molecular alterations, including in genes associated with a dysregulated immune response, proinflammatory signals, and programmed cell death in the liver and kidney. Joint-pathway analysis indicated that the toxicity of TAC was associated with DNA synthesis disruption, oxidative stress, and cell membrane permeabilization, as well as lipid and glucose metabolism. In conclusion, our pathway-level integration of transcriptome and metabolome and conventional analyses of individual omics profiles, provided a more comprehensive picture of the molecular changes resulting from TAC toxicity. This study also serves as a valuable resource for subsequent investigations aiming to understand the mechanism underlying the molecular toxicology of TAC.

Systems-level multi-omics characterization provides novel molecular insights into indomethacin toxicity

The mechanism of indomethacin toxicity at the systemic level is largely unknown. In this study, multi-specimen molecular characterization was conducted in rats treated with three doses of indomethacin (2.5, 5, and 10 mg/kg) for 1 week. Kidney, liver, urine, and serum samples were collected and analyzed using untargeted metabolomics. The kidney and liver transcriptomics data (10 mg indomethacin/kg and control) were subjected to a comprehensive omics-based analysis. Indomethacin exposure at 2.5 and 5 mg/kg doses did not cause significant metabolome changes, whereas considerable alterations in the metabolic profile compared to the control were induced by a dose of 10 mg/kg. Decreased levels of metabolites and an increased creatine level in the urine metabolome indicated injury to the kidney. The integrated omics analysis in both liver and kidney revealed an oxidant-antioxidant imbalance due to an excess of reactive oxygen species, likely originating from dysfunctional mitochondria. Specifically, indomethacin exposure induced changes in metabolites related to the citrate cycle, cell membrane composition, and DNA synthesis in the kidney. The dysregulation of genes related to ferroptosis and suppression of amino acid and fatty acid metabolism were evidence of indomethacin-induced nephrotoxicity. In conclusion, a multi-specimen omics investigation provided important insights into the mechanism of indomethacin toxicity. The identification of targets that ameliorate indomethacin toxicity will enhance the therapeutic utility of this drug.

Integrated spatially resolved metabolomics and network toxicology to investigate the hepatotoxicity mechanisms of component D of Polygonum multiflorum Thunb

ETHNOPHARMACOLOGICAL RELEVANCE

The liver toxicity of Reynoutria multiflora (Thunb.) Moldenke. (Polygonaceae) (Polygonum multiflorum Thunb, PM) has always attracted much attention, but the related toxicity materials and mechanisms have not been elucidated due to multi-component and multi-target characteristics. In previous hepatotoxicity screening, different components of PM were first evaluated and the hepatotoxicity of component D [95% ethanol (EtOH) elution] in a 70% EtOH extract of PM (PM-D) showed the highest hepatotoxicity. Furthermore, the main components of PM-D were identified and their hepatotoxicity was evaluated based on a zebrafish embryo model. However, the hepatotoxicity mechanism of PM-D is unknown.

AIM OF THE STUDY

This work is to explore the hepatotoxicity mechanisms of PM-D by integrating network toxicology and spatially resolved metabolomics strategy.

MATERIALS AND METHODS

A hepatotoxicity interaction network of PM-D was constructed based on toxicity target prediction for eight key toxic ingredients and a hepatotoxicity target collection. Then the key signaling pathways were enriched, and molecular docking verification was implemented to evaluate the ability of toxic ingredients to bind to the core targets. The pathological changes of liver tissues and serum biochemical assays of mice were used to evaluate the liver injury effect of mice with oral administration of PM-D. Furthermore, spatially resolved metabolomics was used to visualize significant differences in metabolic profiles in mice after drug administration, to screen hepatotoxicity-related biomarkers and analyze metabolic pathways.

RESULTS

The contents of four key toxic compounds in PM-D were detected. Network toxicology identified 30 potential targets of liver toxicity of PM-D. GO and KEGG enrichment analyses indicated that the hepatotoxicity of PM-D involved multiple biological activities, including cellular response to endogenous stimulus, organonitrogen compound metabolic process, regulation of the apoptotic process, regulation of kinase, regulation of reactive oxygen species metabolic process and signaling pathways including PI3K-Akt, AMPK, MAPK, mTOR, Ras and HIF-1. The molecular docking confirmed the high binding activity of 8 key toxic ingredients with 10 core targets, including mTOR, PIK3CA, AKT1, and EGFR. The high distribution of metabolites of PM-D in the liver of administrated mice was recognized by mass spectrometry imaging. Spatially resolved metabolomics results revealed significant changes in metabolic profiles after PM-D administration, and metabolites such as taurine, taurocholic acid, adenosine, and acyl-carnitines were associated with PM-D-induced liver injury. Enrichment analyses of metabolic pathways revealed tht linolenic acid and linoleic acid metabolism, carnitine synthesis, oxidation of branched-chain fatty acids, and six other metabolic pathways were significantly changed. Comprehensive analysis revealed that the hepatotoxicity caused by PM-D was closely related to cholestasis, mitochondrial damage, oxidative stress and energy metabolism, and lipid metabolism disorders.

CONCLUSIONS

In this study, the hepatotoxicity mechanisms of PM-D were comprehensively identified through an integrated spatially resolved metabolomics and network toxicology strategy, providing a theoretical foundation for the toxicity mechanisms of PM and its safe clinical application.

Acute bone damage through liver-bone axis induced by thioacetamide in rats

Background

Thioacetamide (TAA) is used in various fields, such as synthetic drugs, organic chemical synthesis, and materials chemistry. TAA is mainly used to establish animal liver injury models and other organ damage models to explore their mechanisms for helping patients with liver disease. Liver damage can lead to abnormal expression of some enzymes in the serum, so we detected the appropriate enzyme levels in the serum of SD rats to verify the damage of TAA to the liver. More importantly, TAA caused bone damage is barely understood. Therefore, our research aims to establish a rat model reflecting the acute bone damage injury caused by TAA.

Methods

The SD rats were intraperitoneally injected with normal saline (0.9%) or TAA (200 mg/kg, 400 mg/kg) for 1 month (once the other day). After the last intraperitoneal injection, serum samples from rats were used for biochemical tests. Masson staining is used to detect liver damage, and micro-CT is used to detect the changes in bone. Moreover, the three-point bending experiment was used to detect the force range of the hind limbs of SD rats.

Results

Compared with the control group, after the intraperitoneal injection of TAA, the levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT), uric acid (UA), total bile acid (TBA), alkaline phosphatase (ALP), carbamide (UREA) and creatinine (CREA) rose sharply, while the levels of serum content of total protein (TP), lactate dehydrogenase (LDH), calcium (Ca) and phosphorus (P) were severely reduced. After TAA administration, collagen fibers were deposited and liver fibrosis was obvious. Micro-CT results showed that the bone surface, tissue surface, bone volume, and tissue volume of rats with an intraperitoneal injection of TAA were significantly reduced. In addition, the bones of rats with an intraperitoneal injection of TAA can resist less pressure and are prone to fractures.

Conclusions

TAA can cause liver damage in SD rats, which is explained by the changes in serum biochemical indicators and the deposition of liver collagen. More importantly, TAA can reduce bone mineral density and increase the separation of bone trabeculae in SD rats, and finally lead to bone injury. This suggests that TAA may become an ideal model to investigate abnormal bone metabolism after liver injury.

Increased hepatic acylcarnitines after oral administration of amiodarone in rats

Amiodarone is known to induce hepatic injury in some recipients. We applied an untargeted metabolomics approach to identify endogenous metabolites with potential as biomarkers for amiodarone-induced liver injury. Oral amiodarone administration for 1 week in rats resulted in significant elevation of acylcarnitines and phospholipids in the liver. Hepatic short- and medium-chain acylcarnitines were dramatically increased in a dose-dependent manner, while the serum levels of these acylcarnitines did not change substantially. In addition, glucose levels were significantly increased in both the serum and liver. Gene expression profiling showed that the hepatic mRNA levels of Cpt1, Cpt2, and Acat1 were significantly suppressed, whereas those of Acot1, Acly, Acss2, and Acsl3 were increased. These results suggest that hepatic acylcarnitines and glucose levels might be increased due to disruption of mitochondrial function and suppression of glucose metabolism. Perturbation of energy metabolism might be associated with amiodarone-induced hepatotoxicity.

Plasma metabolites as possible biomarkers for diagnosis of breast cancer

Metabolomic approaches have been used to identify new diagnostic biomarkers for various types of cancers, including breast cancer. In this study, we aimed to identify potential biomarkers of breast cancer using plasma metabolic profiling. Furthermore, we analyzed whether these biomarkers had relationships with clinicopathological characteristics of breast cancer. Our study used two liquid chromatography-mass spectrometry sets: a discovery set (40 breast cancer patients and 30 healthy controls) and a validation set (30 breast cancer patients and 16 healthy controls). All breast cancer patients were randomly selected from among stage I–III patients who underwent surgery between 2011 and 2016. First, metabolites distinguishing cancer patients from healthy controls were identified in the discovery set. Then, consistent and reproducible metabolites were evaluated in terms of their utility as possible biomarkers of breast cancer. Receiver operating characteristic (ROC) analysis was applied to the discovery set, and ROC cut-off values for the identified metabolites derived therein were applied to the validation set to determine their diagnostic performance. Ultimately, four candidate biomarkers (L-octanoylcarnitine, 5-oxoproline, hypoxanthine, and docosahexaenoic acid) were identified. L-octanoylcarnitine showed the best diagnostic performance, with a 100.0% positive predictive value. Also, L-octanoylcarnitine levels differed according to tumor size and hormone receptor expression. The plasma metabolites identified in this study show potential as biomarkers allowing early diagnosis of breast cancer. However, the diagnostic performance of the metabolites needs to be confirmed in further studies with larger sample sizes.

Identification and characterization of amiodarone metabolites in rats using UPLC-ESI-QTOFMS-based untargeted metabolomics approach

Amiodarone is a class III anti-arrhythmic benzofuran derivative extensively utilized in treatment of life-threatening ventricular and supraventricular arrhythmias. However, amiodarone also produces adverse side effects including liver injury due to its metabolites rather than parent drug. The purpose of the present study was to identify metabolites of amiodarone in the plasma and urine of rats administered the drug by using an untargeted metabolomics approach. Drug metabolites were profiled by ultra-performance liquid chromatography-linked electrospray ionization quadrupole time-of-flight mass spectrometry (UPLC-ESI-QTOFMS) and results subjected to multivariate data analysis. A total of 49 amiodarone metabolites were identified and their structures were characterized by tandem mass spectrometry. Amiodarone metabolites are presumed to be generated via five major types of metabolic reactions including N-desethylation, hydroxylation, carboxylation (oxo/hydroxylation), de-iodination, and glucuronidation. Data demonstrated that an untargeted metabolomics approach appeared to be a reliable tool for identifying unknown metabolites in a complex biological matrix.

Profiling of the circadian metabolome in thioacetamide-induced liver cirrhosis in mice

Liver cirrhosis can disturb circadian rhythms, decreasing patient quality of life. Changes in metabolic products in cirrhosis are poorly understood. We evaluated changes in liver metabolism products using a thioacetamide‐induced mouse model of liver cirrhosis exhibiting circadian rhythm disturbance. Principal component analysis indicated that the circular progression found in the control group was disrupted in the thioacetamide group, and Jonckheere‐Terpstra‐Kendall analysis showed an imbalanced pattern of oscillating metabolic products. In addition to changes in serotonin and other vitamin A–related metabolites, differences in metabolic products associated with energetics, redox homeostasis, bile acid production, inflammation, and other processes were identified. Carbohydrate metabolism showed a reduction in metabolic products associated with the tricarboxylic acid cycle, suggesting up‐regulation of glycolysis and reduced mitochondrial activity. Lipid metabolism showed an increase in ω‐oxidation products, suggesting decreased β‐oxidation. Conclusion: These data will be useful for chronotherapy and modulation of circadian rhythms in patients with liver damage. (Hepatology Communications 2017;1:704–718)

Characterization of urinary metabolites as biomarkers of colistin-induced nephrotoxicity in rats by a liquid chromatography/mass spectrometry-based metabolomics approach

Colistin is a polypeptide antibiotic that effectively treats infections caused by multidrug-resistant Gram-negative bacteria, but its clinical use is limited due to nephrotoxicity. The purpose of the present study was to identify biomarkers of colistin-induced nephrotoxicity and to further characterize the mechanisms underlying this process by analyzing urinary metabolites using untargeted metabolomic approach. Rats receiving intraperitoneal administration of colistin sodium methanesulfonate (CMS) (25 or 50mg/kg) exhibited histopathological changes in the kidney and increased blood urea nitrogen levels. Additionally, the levels of phenylalanine, tryptophan, and tyrosine in the urine of the CMS-treated group were significantly higher than those of the control group, suggesting that colistin caused proximal tubular damage. Urinary acetylcarnitine and butyrylcarnitine levels also increased after CMS treatment, but the levels of purine metabolites and metabolites related to the tricarboxylic acid cycle were reduced. The most significant increase in the CMS-treated groups was observed in creatine levels. CMS-induced selective nephrotoxicity may be attributed to relatively high tissue concentrations of colistin in the kidney. Taken together, our results indicate that high levels of colistin in the kidney caused perturbations in the tricarboxylic acid cycle, amino acid metabolism, creatine metabolism, and purine metabolism and ultimately led to kidney injury.

The Need for Biomarkers in Diagnosis and Prognosis of Drug-Induced Liver Disease: Does Metabolomics Have Any Role?

Drug-induced liver injury (DILI) is a potentially fatal adverse event and the leading cause of acute liver failure in the US and in the majority of Europe. The liver can be affected directly, in a dose-dependent manner, or idiosyncratically, independently of the dose, and therefore unpredictably. Currently, DILI is a diagnosis of exclusion that physicians should suspect in patients with unexplained elevated liver enzymes. Therefore, new diagnostic and prognostic biomarkers are necessary to achieve an early and reliable diagnosis of DILI and thus improve the prognosis. Although several DILI biomarkers have been found through analytical and genetic tests and pharmacokinetic approaches, none of them have been able to display enough specificity and sensitivity, so new approaches are needed. In this sense, metabolomics is a strongly and promising emerging field that, from biofluids collected through minimally invasive procedures, can obtain early biomarkers of toxicity, which may constitute specific indicators of liver damage.