Gynura root induces hepatic veno-occlusive disease: A case report and review of the literature

Association between pyrrolizidine alkaloids exposure and risk of abnormal serum indices-Insights from a descriptive cross-sectional study in Yunnan Province

The hazard of pyrrolizidine alkaloids (PAs) has been widely reported in animal studies but rarely in population-based research, especially reports about daily exposure. A single-centre descriptive cross-sectional study was conducted on 552 Lahu Autonomous County residents recruited in 2021. Blood PAs exposure biomarker (pyrrole- protein adduct, PPA) and serum biochemical indices were measured. The prevalence of abnormal serum indices and PAs exposure in this region were elucidated using descriptive analyses. 75 % of Lahu Autonomous County participants were exposed to PAs. PAs exposure risk in males was lower than in females (OR=0.357, 95 % CI: 0.222-0.574), and varied with the ethnicity of Lahu Autonomous County. PPA concentration was positively correlated with serum alanine transaminase (ALT) activity (r=0.6263, P < 0.01) and triglyceride level (r=0.2327, P < 0.01); PAs exposure was positively associated with anbormal serum ALT activity (x2=99.629, P < 0.001; OR=1.428, 95 % CI: 1.293-2.319) and hypertriglyceridemia (x2=15.376, P < 0.001; OR=1.629, 95 % CI: 1.229-2.251). These results suggest that PAs exposure might be a risk factor for serum ALT abnormality and hypertriglyceridemia in the local population. This study conducted the first epidemiological study on PAs exposure in China and established the etiological hypotheses for health issues in Lahu Autonomous County.

Rifaximin Prevents Intestinal Barrier Dysfunction and Alleviates Liver Injury in MCT-induced HSOS Mice

OBJECTIVE

Rifaximin is an effective component of treatment strategies for liver and intestinal diseases. However, the efficacy of rifaximin in hepatic sinusoidal obstruction syndrome (HSOS) has not been explored. The present study aimed to investigate the efficacy and mechanism of rifaximin in HSOS.

METHODS

An HSOS model was established in mice through the administration of monocrotaline (MCT, 800 mg/kg), and part of the HSOS mice were intragastrically administered with rifaximin. Then, the efficacy of rifaximin in HSOS was evaluated based on the liver pathological findings, liver proinflammatory cytokines, and alanine aminotransferase and aspartate aminotransferase levels. The Ussing chamber was used to evaluate the intestinal permeability, and tight junction (TJ) proteins were measured by Western blotting and real-time polymerase chain reaction to evaluate the intestinal barrier integrity. Then, the serum proinflammatory cytokine levels were evaluated by enzyme-linked immunosorbent assay. Afterwards, an in vitro experiment was performed to determine the relationship between rifaximin and TJ proteins.

RESULTS

Rifaximin effectively alleviated the MCT-induced HSOS liver injury, suppressed the expression of liver proinflammatory cytokines, and reduced the serum levels of tumor necrosis factor-alpha and interleukin-6. Furthermore, rifaximin reduced the intestinal permeability, improved the intestinal barrier integrity, and promoted the expression of TJ proteins.

CONCLUSION

The results revealed that the intestinal barrier integrity was destroyed in MCT-induced HSOS. The significant alleviation of MCT-induced HSOS induced by rifaximin might be correlated to the repairment of intestinal barrier integrity via the regulation of the TJ protein expression.

The chemical structure impairs the intensity of genotoxic effects promoted by 1,2-unsaturated pyrrolizidine alkaloids in vitro

1,2-unsaturated pyrrolizidine alkaloids (PAs) represent a large group of secondary plant metabolites exhibiting hepatotoxic, genotoxic, and carcinogenic properties upon bioactivation. To examine how the degree of esterification affects the genotoxic profile of PA we investigated cytotoxicity, histone H2AX phosphorylation, DNA strand break induction, cell cycle perturbation, micronuclei formation, and aneugenic effects in different cell models. Analysis of cytotoxicity and phosphorylation of histone H2AX was structure- and concentration-dependent: diester-type PAs (except monocrotaline) showed more pronounced effects than monoester-type PAs. Cell cycle analysis identified that diester-type PAs induced a S-phase arrest and a decrease in the occurrence of cells in the G1-phase. The same structure-dependency was observed by flow-cytometric analysis of PA-induced micronuclei in CYP3A4-overexpressing V79 cells. Analysis of centromeres induced by lasiocarpine in the micronuclei by fluorescence in situ hybridization indicated an aneugenic effect in V79_h3A4 cells. Comet assays revealed no significant induction of DNA strand breaks for all investigated PAs. Overall, diester-type PAs induced more pronounced effects than monoester-type PAs. Furthermore, our results indicate aneugenic effects upon exposure towards lasiocarpine in vitro. These data improve our understanding how structural features of PA influence the genotoxic profile. Especially, the monoester-type PAs seem to induce less severe effects than other PAs.

Liquorice Extract and 18β-Glycyrrhetinic Acid Protect Against Experimental Pyrrolizidine Alkaloid-Induced Hepatotoxicity in Rats Through Inhibiting Cytochrome P450-Mediated Metabolic Activation

Misuse of pyrrolizidine alkaloid (PA)-containing plants or consumption of PA-contaminated foodstuffs causes numerous poisoning cases in humans yearly, while effective therapeutic strategies are still limited. PA-induced liver injury was initiated by cytochrome P450 (CYP)-mediated metabolic activation and subsequent formation of adducts with cellular proteins. Liquorice, a hepato-protective herbal medicine, is commonly used concurrently with PA-containing herbs in many compound traditional Chinese medicine formulas, and no PA-poisoning cases have been reported with this combination. The present study aimed to investigate hepato-protective effects of liquorice aqueous extract (EX) and 18β-glycyrrhetinic acid (GA, the primary bioactive constituent of liquorice) against PA-induced hepatotoxicity and the underlying mechanism. Histopathological and biochemical analysis demonstrated that both single- and multiple-treatment of EX (500 mg/kg) or GA (50 mg/kg) significantly attenuated liver damage caused by retrorsine (RTS, a representative hepatotoxic PA). The formation of pyrrole-protein adducts was significantly reduced by single- (30.3% reduction in liver; 50.8% reduction in plasma) and multiple- (32.5% reduction in liver; 56.5% reduction in plasma) treatment of GA in rats. Single- and multiple-treatment of EX also decreased the formation of pyrrole-protein adducts, with 30.2 and 31.1% reduction in rat liver and 51.8 and 53.1% reduction in rat plasma, respectively. In addition, in vitro metabolism assay with rat liver microsomes demonstrated that GA reduced the formation of metabolic activation-derived pyrrole-glutathione conjugate in a dose-dependent manner with the estimated IC50 value of 5.07 µM. Further mechanism study showed that GA inhibited activities of CYPs, especially CYP3A1, the major CYP isoform responsible for the metabolic activation of RTS in rats. Enzymatic kinetic study revealed a competitive inhibition of rat CYP3A1 by GA. In conclusion, our findings demonstrated that both EX and GA exhibited significant hepato-protective effects against RTS-induced hepatotoxicity, mainly through the competitive inhibition of CYP-mediated metabolic activation of RTS.

Herbs and their bioactive ingredients in cardio-protection: Underlying molecular mechanisms and evidences from clinical studies

BACKGROUND

Medicinal plants or herbs produce a bounty of bioactive phytochemicals. These phytochemicals can influence a variety of physiological events related to cardiovascular health through multiple underlying mechanisms, such as their role as antioxidative, anti-ischemic, anti-proliferative, hypotensive, anti-thrombotic, and anti-hypercholesterolemic agents.

PURPOSE

The purpose of this review is to summarize and connect evidences supporting the use of phytotherapy in the management of some of the most common cardiovascular impairments, molecular mechanisms underlying cardio-protection mediated by herbs, and clinical studies which are positively linked with the use of herbs in cardiovascular biology. Additionally, we also describe several adverse effects associated with some of the herbal plants and their products to provide a balanced set of studies in favor or against phytotherapy in cardiovascular health that may help global discourses on this matter.

METHODS

Studies relating to the use of medicinal plants were mined by strategically searching scientific databases including Google Scholar, PubMed and Science Direct. Investigations involving approximately 175 articles including reviews, research articles, meta-analyses, and cross-sectional and observational studies were retrieved and analyzed in line with the stated purpose of this study.

RESULTS

A positive correlation between the use of medicinal plants and cardiovascular health was observed. While maintaining cardiovascular physiology, medicinal plants and their derivatives seem to govern a variety of cellular mechanisms involved in vasoconstriction and vasorelaxation, which in turn, are important aspects of cardiovascular homeostasis. Furthermore, a variety of studies including clinical trials, cross-sectional studies, and meta-analyses have also supported the anti-hypertensive and thus, cardio-protective effects, of medicinal plants. Apart from this, evidence is also available for the potential drawbacks of several herbs and their products indicating that the unsupervised use of many herbs may lead to severe health issues.

CONCLUSIONS

The cardio-protective outcomes of medicinal plants and their derivatives are supported by ever-increasing studies, while evidences exist for the potential drawbacks of some of the herbs. A balanced view about the use of medicinal plants and their derivative in cardiovascular biology thus needs to be outlined by researchers and the medical community. The novelty and exhaustiveness of the present manuscript is reflected by the detailed outline of the molecular basis of "herbal cardio-protection", active involvement of several herbs in ameliorating the cardiovascular status, adverse effects of medicinal plants, and the clinical studies considering the use of phytotherapy, all on a single platform.

Characterization of liver injury induced by a pyrrolizidine alkaloid in rats

BACKGROUND

Pyrrolizidine alkaloids (PAs) are common phytotoxins. PA intoxication is reported to cause severe acute liver damage, typically known as hepatic sinusoidal obstruction syndrome (HSOS), but it remains obscure whether the acute liver damage may progress into chronic liver disease characterized by hepatic fibrosis.

PURPOSE

This study aims to characterize the biochemical markers of liver injury and histological features of regressive and progressive liver fibrosis, and to examine changes in hepatic gene expression that may underpin mechanisms of fibrogenesis in rats induced by retrorsine (RTS), a representative toxic PA.

STUDY DESIGN/METHODS

Rats were gavaged with RTS via two dosing regimens, i.e. a single dose of 40 mg/kg (Group 1) and two doses of 40 mg/kg and 20 mg/kg on day 0 and day 7 (Group 2), respectively. Rats receiving one (Group 3) or two (Group 4) doses of vehicle served as negative controls. The animals were followed for up to 16 weeks by serum biochemical analyses and histological examination, and gene expression assays of liver tissues.

RESULTS

Acute liver injury on day 2 manifested as HSOS, characterized by sinusoidal dilation, endothelial cell damage, and elevated serum alanine aminotransferase activity and bilirubin levels. In Group 1, mild liver fibrosis developed at sinusoids and perisinusoidal space surrounding the central veins at week 1 and 2, and thereafter, all liver injury resolved gradually. In Group 2, liver fibrosis progressed within the 16-week observation period. No apparent liver injury was observed in Groups 3 and 4. Compared with negative control groups, RTS induced myofibroblastic activation, TGF-β1 signaling, and changes in expression of matrix metalloproteinase 9 (MMP-9) and tissue inhibitor of metalloproteinase 1 (TIMP-1). These dynamic changes differed in Groups 1 and 2, corresponding with the regression and progression of liver fibrosis, respectively, in these groups.

CONCLUSION

This study has provided in-vivo proof of concept that "one hit" and "two hits" of RTS lead to acute resolving liver injury and chronic progressive liver fibrosis, respectively. These animal models may serve as powerful tools for studying RTS toxicology and related preventive and therapeutic strategies and as positive controls for studying other PA- and non-PA-induced liver injury.

Hepatic sinusoidal obstruction syndrome caused by the ingestion of Gynura segetum in a patient with alcoholic cirrhosis: a case report

Hepatic sinusoidal obstruction syndrome (HSOS) is a rare hepatic vascular disorder characterized by intrahepatic congestion, liver injury, and post-sinusoidal portal hypertension, and it is frequently associated with hematopoietic stem cell transplantation. In this study, we observed a case of HSOS associated with the ingestion of Gynura segetum, a pyrrolizidine alkaloid (PA)-containing Chinese herb, in a patient with alcoholic cirrhosis. The patient was a 43-year-old man with chief complaints of physical asthenia and a loss of appetite for more than a month. The diagnosis of HSOS combined with alcoholic cirrhosis was confirmed via the histopathological examination of liver tissues. With proper supportive and symptomatic care and anticoagulation therapy using low-molecular-weight heparin, the patient’s condition was stabilized. Because of its nonspecific symptoms in the early stage and a lack of information about PA consumption, PA-induced HSOS (PA-HSOS) has been long neglected, especially in patients with underlying liver diseases. Early identification and intervention are critical for optimizing outcomes. Further efforts are needed to supervise the use of PA-containing herbal medicines and identify accurate biomarkers for PA-HSOS.

Pyrrolizidine alkaloids from the seeds of Scleropyrum wallichianum

Two new pyrrolizidine alkaloids, sclerwalins A and B (1 and 2), and one known 9-O-E-hydroxysenecioylretronecine (3) were first isolated from the seeds of Scleropyrum wallichianum. Their chemical structures were elucidated by extensive 1 D NMR and 2 D NMR (HSQC, HMBC, COSY, and ROESY), MS and IR spectra. Cytotoxicities of all isolates were evaluated against five human tumor cell lines (HL-60, A-549, SMMC-7721, MCF-7 and SW480).[Formula: see text].

Drug-induced liver injury: Asia Pacific Association of Study of Liver consensus guidelines

Idiosyncratic drug-induced liver injury mimics acute and chronic liver disease. It is under recognized and underrecognised because of the lack of pathognomonic diagnostic serological markers. Its consequences may vary from being asymptomatic to self-limiting illness to severe liver injury leading to acute liver failure. Its incidence is likely to be more common in Asia than other parts of the world, mainly because of hepatotoxicity resulting from the treatment of tuberculosis disease and the ubiquitous use of traditional and complimentary medicines in Asian countries. This APASL consensus guidelines on DILI is a concise account of the various aspects including current evidence-based information on DILI with special emphasis on DILI due to antituberculosis agents and traditional and complementary medicine use in Asia.

Determination of Toxic Pyrrolizidine Alkaloids in Traditional Chinese Herbal Medicines by UPLC-MS/MS and Accompanying Risk Assessment for Human Health

Pyrrolizidine alkaloids (PAs) are a class of natural toxins with hepatotoxicity, genotoxicity and carcinogenicity. They are endogenous and adulterated toxic components widely found in food and herbal products. In this study, a sensitive and efficient ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was used to detect the PAs in 386 kinds of Chinese herbal medicines recorded in the Chinese Pharmacopoeia (2020). The estimated daily intake (EDI) of 0.007 μg/kg body weight (bw)/day was adopted as the safety baseline. The margin of exposure (MOE) approach was applied to evaluate the chronic exposure risk for the genotoxic and carcinogenic potential of PAs. Results showed that PAs was detected in 271 out of 386 samples with a content of 0.1–25,567.4 μg/kg, and there were 20 samples with EDI values above the baseline, 0.007 μg/kg bw/day. Beyond that, the MOE values for 10 out of 271 positive samples were below 10,000. Considering the actual situation, Haber’s rule was used to assume two weeks exposure every year during lifetime, and still the MOE values for four out of 271 positive samples were under 10,000, indicating these products may have potential health risk. The developed method was successfully applied to detect the PAs-containing Chinese herbal medicines. This study provides convincing data that can support risk management actions in China and a meaningful reference for the rational and safe use of Chinese herbal medicines.

Prognostic factors for pyrrolizidine alkaloid-induced hepatic sinusoidal obstruction syndrome: a multicenter study in China

BACKGROUND

In China, one of the major causes of hepatic sinusoidal obstruction syndrome (HSOS) is the intake of herbals containing pyrrolizidine alkaloid (PA). However, prognostic factors for PA-induced HSOS are poorly understood. The aim of this study was to identify the independent prognostic factors for PA-induced HSOS using a multi-center study.

METHODS

A total of 117 PA-induced HSOS patients were enrolled for data collection in three university hospitals from November 2003 to September 2018. Univariate and multivariate Cox proportional hazards analysis were used to determine prognostic factors for PA-induced HSOS.

RESULTS

The median age of the PA-induced HSOS patients was 61 years (range, 21-88 years), and 64% of them were male. The survival rates at 1, 3, and 36 months were 89.71%, 72.60%, and 69.19%, respectively. Significant differences in prothrombin time (PT), international normalized ratio, total bilirubin, severity grading [new criteria for severity grading of hematopoietic stem cell transplantation (HSCT)-related HSOS in adults] were found between patients who survived and those who died. Univariate and multivariate survival analysis using Cox's regression model demonstrated low serum albumin (<35 g/L), elevated serum urea (>8.2 mmol/L) and severe or very severe HSOS (European Society for Blood and Marrow Transplantation 2016 criteria) were independent prognostic factors of survival.

CONCLUSIONS

Serum albumin, serum urea, and severity grading were independent prognostic factors for patients with PA-induced HSOS, and can contribute to identifying potentially high-risk patients for early effective intervention.

TRIAL REGISTRATION

ChiCTR-DRD-17010709 (www.chictr.org.cn).

Hepatic veno-occlusive disease may be a rare characteristic of hepatic involvement in systemic amyloidosis: case report and literature review

Systemic amyloidosis is a rare disease and patients with hepatic amyloidosis often present with hepatomegaly. Hepatomegaly can also be a feature of hepatic veno-occlusive disease (HVOD). We report here a case of systemic amyloidosis in a patient who was suspected of having HVOD. On the basis of computed tomography findings in the abdomen, HVOD was initially suspected in a 63-year-old man with the chief complaint of upper abdominal pain, ascites, and weight loss. Multiple patchy purpura and nerve symptoms were identified and these were due to amyloidosis. An increase in proteinuria and immunoglobulin κ light-chain levels, and thickening of the ventricular wall supported the diagnosis of systemic light-chain amyloidosis involving the liver, heart, kidney, skin, and nerves. This diagnosis was confirmed by histological examination of a bone marrow core biopsy with Congo red dye. Sequential treatment of bortezomib and dexamethasone led to good results in the patient. Findings of this rare case indicate that HVOD can be diagnosed without a definite history of hematopoietic stem cell transplantation or pyrrolizidine alkaloid ingestion, but more evidence is required to make an accurate diagnosis. Importantly, we speculate that HVOD is a rare characteristic of liver involvement in systemic amyloidosis.

Clinical efficacy and safety of anticoagulation therapy for Pyrrolizidine alkaloids-induced hepatic sinusoidal obstruction syndrome: a retrospective multicenter cohort study

AIM

Pyrrolizidine alkaloids-induced hepatic sinusoidal obstruction syndrome(PA-HSOS) has been reported to have high mortality. We evaluated the efficacy and safety of anticoagulation therapy for the patients with PA-HSOS.

METHODS

We collected clinical data on 249 PA-HSOS patients from January 2012 to December 2017 at four tertiary care hospitals. Among them, 151 patients received anticoagulation therapy, and 98 patients received supportive treatment. The outcomes were analyzed using the Fine and Gray competing risk analysis method and Cox regression model.

RESULTS

The cumulative complete response rate was higher in the anticoagulation group than in the supportive group (60.9 vs 36.7%; P < 0.0001). The cumulative mortality was 12.6% in the anticoagulation group compared with 43.9% in the supportive group (P < 0.0001). In subgroup analysis, for mild, moderate, severe, and very severe groups, the adjusted hazard ratios [95% confidence interval (CI)] for complete response rates were 7.05 (3.00-16.59), 5.26 (2.31-12.42), 2.59 (0.85-7.87), and 2.05 (0.61-6.92), respectively; and the adjusted hazard ratios (95% CI) for mortalities were 0.02 (0.01-0.09), 0.04 (0.01-0.14), 0.19 (0.01-3.98), and 0.07 (0.02-1.27), respectively (P < 0.0001). There was no significant difference between both groups in the incidence of bleeding events (P = 0.674).

CONCLUSIONS

Anticoagulation therapy improves clinical remission and the survival in selected patients with mild or moderate PA-HSOS. Anticoagulation therapy has a similar safety profile to supportive therapy.

Liver Inflammatory Injury Initiated by DAMPs-TLR4-MyD88/TRIF-NFκB Signaling Pathway Is Involved in Monocrotaline-Induced HSOS

Hepatic sinusoidal obstruction syndrome (HSOS) causes considerable morbidity and mortality in clinic. Up to now, the molecular mechanisms involved in the development of HSOS still remain unclear. Here, we report that hepatic inflammation initiated by damage-associated molecular patterns (DAMPs) plays a critical role in the development of HSOS. Monocrotaline (MCT) belongs to pyrrolizidine alkaloids. Monocrotaline-induced HSOS in mice and rats was evidenced by the increased serum alanine/aspartate aminotransferase (ALT/AST) activities, the elevated hepatic metalloproteinase 9 (MMP9) expression, and results from liver histological evaluation and scanning electron microscope observation. However, MCT-induced HSOS was markedly attenuated in myeloid differentiation primary response gene 88 (MyD88), TIR-domain-containing adapter-inducing interferon-β (TRIF) and toll like receptor 4 (TLR4) knock-out mice. Monocrotaline increased liver myeloperoxidase activity, serum contents of proinflammatory cytokines, hepatic aggregation of immune cells, and nuclear accumulation of nuclear factor κB (NFκB). However, these inflammatory responses induced by MCT were all diminished in MyD88, TRIF, and TLR4 knock-out mice. Monocrotaline elevated serum contents of DAMPs including high mobility group box 1 (HMGB1) and heat shock protein 60 (HSP60) both in mice and in rats. HSOS was markedly exacerbated and serum contents of HMGB1 and HSP60 were elevated in nuclear factor erythroid 2-related factor 2 (Nrf2) knock-out mice treated with MCT. Our findings indicate that hepatic inflammatory injury mediated by DAMPs-initiated TLR4-MyD88/TRIF-NFκB inflammatory signal pathway plays an important role in HSOS development.

Clinical characteristics and outcomes of patients with hepatic veno-occlusive disease induced by Gynura segetum: A retrospective study

OBJECTIVE

Hepatic veno-occlusive disease (HVOD) has attracted increasing attention in recent years due to its relationship with ingestion of Gynura segetum. The mortality of severe HVOD remains high due to the lack of specific therapies. The aim of the study was to delineate the clinical characteristics and outcomes and explore the potential prognostic factors of HVOD.

METHODS

This was a single-center retrospective study. Eighty-nine HVOD patients were screened from the First Affiliated Hospital of Zhejiang University with an ingestion history of G. segetum before developing symptoms from January 2009 to May 2018. The enrolled patients were divided into the survivor and death groups according to the clinical follow-up that ended on September 1, 2019. The demographic variables and clinical data of the patients were recorded. A binary logistic regression analysis and receiver operating characteristic curve were conducted to identify the prognostic factors and assess the prognostic value for predicting death, and a survival analysis was performed to evaluate the clinical outcomes.

RESULTS

Sixty-four patients were eligible for further analysis. Most patients showed abdominal distension and were positive for migrating dullness in the abdomen (P = 0.740 and P = 0.732, respectively). The patients who died had higher levels of model for end-stage liver disease score, and higher prothrombin time than those who survived (both P < 0.001). All HVOD patients in both the survival and death groups showed ascites with abnormal imaging presentations of the liver parenchyma and hepatic blood vessels. Unexpectedly, we found that hydrothorax was detected in 21 (65.63%) patients in the death group and 19 (59.38%) patients in the survivor group during hospitalization, which was rarely mentioned in previous studies. Furthermore, international normalized ratio (INR) and creatinine are found to be potential independent prognostic factors for predicting death. Six severe patients achieved clinical improvements and survived after liver transplantation.

CONCLUSION

HVOD can be induced by the ingestion of G. segetum, and INR combined with creatinine has prognostic value for predicting death. Liver transplantation may be an effective treatment option for severe HVOD patients.

Seneciphylline, a main pyrrolizidine alkaloid in Gynura japonica, induces hepatotoxicity in mice and primary hepatocytes via activating mitochondria-mediated apoptosis

Herbal drug-induced liver injury has been reported worldwide and gained global attention. Thousands of hepatic sinusoidal obstruction syndrome (HSOS) cases have been reported after consumption of herbal medicines and preparations containing pyrrolizidine alkaloids (PAs), which are natural phytotoxins globally distributed. And herbal medicines, such as Gynura japonica, are the current leading cause of PA-induced HSOS. The present study aimed to reveal the mechanism underlying the hepatotoxicity of seneciphylline (Seph), a main PA in G. japonica. Results showed that Seph induced severe liver injury through apoptosis in mice (70 mg/kg Seph, orally) and primary mouse and human hepatocytes (5-50 μM Seph). Further research uncovered that Seph induced apoptosis by disrupting mitochondrial homeostasis, inducing mitochondrial depolarization, mitochondrial membrane potential (MMP) loss, and cytochrome c (Cyt c) release and activating c-Jun N-terminal kinase (JNK). The Seph-induced apoptosis in hepatocytes could be alleviated by Mdivi-1 (50 μM, a dynamin-related protein 1 inhibitor), as well as SP600125 (25 μM, a specific JNK inhibitor) and ZVAD-fmk (50 μM, a general caspase inhibitor). Moreover, the Seph-induced MMP loss in hepatocytes was also rescued by Mdivi-1. In conclusion, Seph induced liver toxicity via activating mitochondrial-mediated apoptosis in mice and primary hepatocytes. Our results provide further information on Seph detoxification and herbal medicines containing Seph such as G. japonica.

Monitoring of pyrrolizidine alkaloids in beehive products and derivatives on the Belgian market

Pyrrolizidine alkaloids (PAs) and related N-oxides (PANOs) are secondary plant metabolites thought to be found in approximately 3% of the flowering plants worldwide and exhibiting hepatotoxic properties to humans. As a consequence, beehive products are prone to be contaminated with those compounds by bees foraging PA-producing plants. Downstream contamination can also occur through food items containing honey. Analytical methods based on UHPLC separation and MS/MS detection were developed with a focus on very low LOQs and validated for the analysis of 16 PAs and 14 PANOs in honey, honey-based candies and snacks, as well as beehive product-based food supplements. A maximum level of 182 ng/g of PAs was detected in a Mediterranean honey, and high levels of heliotrine-type compounds were reported for the first time. An extensive sampling of honeys harvested in Belgium was performed (N = 374), the concentration levels were more limited with a maximum of 60 ng/g, and the contamination pattern was dominated by senecionine-type PAs. The PA levels in honey-based candies and snacks were very low, with respective maxima of 7.61 ng/g and 0.36 ng/g. Seventy-five percent among the pre-dosed food supplements based on beehive products were contaminated, with a maximum of 43 ng/g. The highest level was detected in a bee-collected pollen sample (1672 ng/g). The analytical results were consistent with the previously reported data for beehive products and confirmed that PA/PANO contamination in these food commodities is recurrent.

The long persistence of pyrrolizidine alkaloid-derived pyrrole-protein adducts in vivo: Kinetic study following multiple exposures of a pyrrolizidine alkaloid containing extract of Gynura japonica

Gynura japonica (also named Tusanqi in Chinese) is used as a folk herbal medicine for treating blood stasis or traumatic injury. However, hundreds of hepatic sinusoidal obstruction syndrome (HSOS) cases have been reported after consumption of preparations made from G. japonica because it contains large amounts of hepatotoxic pyrrolizidine alkaloids (PAs). To date, blood pyrrole-protein adducts (PPAs) are suggested as biomarkers for the diagnosis of PA-induced HSOS in clinics. However, the concentration of PPAs in the blood is greatly affected by several factors including the amount of PA exposure, herb intake period, and blood sampling time after the last exposure. In present study, the kinetic characters of PPAs in serum and liver as well as other potential target organs were studied systematically and comprehensively following multiple exposures of PAs in G. japonica extract (GJE). As results, PPAs content reached to a plateau both in serum and liver after the mice were treated with GJE for 2 weeks on daily basis. PPAs cleared significantly slower in liver (T_1/2ke∼184.6 h, ∼7.7 days) than in serum (T_1/2ke∼95.8 h, ∼4.0 days). Although more than 90 % PPAs were removed 2 weeks after the last dosing, PPAs still persisted in the liver until the end of the experiment, i.e. 8 weeks after the last dosing. The results would be of great help for understanding the importance of PPAs for PA-induced toxicity and its detoxification.

Antibody-based detection of lysine modification of hepatic protein in mice treated with retrorsine

Many pyrrolizidine alkaloids (PAs), an important class of natural products, are hepatotoxic and carcinogenic. Increased attention has been paid to PA poisoning cases worldwide. Generally, most PAs themselves are not toxic. However, reactive intermediates formed from PAs by metabolic oxidation have been linked to toxicity and carcinogenesis. PAs themselves are generally not toxic, and their reactive metabolites resulting from metabolic oxidation are considered to be an essential responsible for PA toxicities. Protein modification by the electrophilic metabolites is proposed to play a key role in PA-induced cytotoxicity. The present study investigated the interaction of lysine residues of proteins with reactive metabolites of toxic PAs. Antibodies selectively recognizing lysine-based protein adduction were prepared and characterized. ELISA and immunoblot methods, in the presence and absence of synthetic model PA adducts, were used to test specific binding of the antibodies to modified lysine residues of BSA and to hepatic proteins extracted from mice treated with retrorsine. The lysine residue adduction was also detected in the tissues of retrorsine-treated mice by use of an immunohistochemical approach. In conclusion, the prepared antibodies selectively recognized the lysine adducts and may be used for the investigation of mechanisms of toxic action of PAs.

Gynura Segetum Related Hepatic Sinusoidal Obstruction Syndrome: A Liver Disease with High Mortality and Misdiagnosis Rate

Background and Aim:

Gynura segetum (Tusanqi or Jusanqi) is widely used in China as a herbal remedy, however, it has often been associated with hepatic sinusoidal obstruction syndrome (HSOS). Its extent in inducing hepatotoxicity is not sufficiently understood. Hence, we aimed to identify the characteristic features of Gynura segetum associated HSOS.

Methods:

A total of 64 patients diagnosed with HSOS induced by gynura segetum were enrolled from eight Chinese tertiary care hospitals between 2008 and 2018. General information regarding diagnosis, disease history, suspected drug use, symptoms and signs, biochemical index, imaging data, liver histology, treatment methods, severity and prognosis were collected and analyzed.

Results:

The mean age of the enrolled patients were 58.07±11.44 years. Male patients accounted for 64.1% of HSOS patients. The median latency period was 75 days. The number of patients with a definite diagnosis from the eight hospitals was 5 (7.81%), with a misdiagnosis rate of 92.18%. Hepatomegaly, splenomegaly, ascites and lower limbs edema were present in 89.1%, 76.6%, 81.3% and 43.8% of the patients, respectively. The imaging characteristic changes were liver parenchyma echo thickening, uneven density, and hepatic vein stenosis and occlusion. Liver biopsies had characteristic pathological changes. Except for ALT and D-Dimer, liver function and coagulation index at admission and before discharge were not significantly different (p>0.05). The 6-month mortality rate was 77.55%, with upper-gastrointestinal bleeding being the leading cause of death (42.11%). The second leading cause of death was a secondary infection (36.84%), while the third was hepatorenal syndrome (21.05%).

Conclusion:

Gynura segetum related HSOS often presents as progressive hepatic congestion, portal hypertension and liver failure, and has a high mortality and misdiagnosis rate.

EASL Clinical Practice Guidelines: Drug-induced liver injury

Idiosyncratic (unpredictable) drug-induced liver injury is one of the most challenging liver disorders faced by hepatologists, because of the myriad of drugs used in clinical practice, available herbs and dietary supplements with hepatotoxic potential, the ability of the condition to present with a variety of clinical and pathological phenotypes and the current absence of specific biomarkers. This makes the diagnosis of drug-induced liver injury an uncertain process, requiring a high degree of awareness of the condition and the careful exclusion of alternative aetiologies of liver disease. Idiosyncratic hepatotoxicity can be severe, leading to a particularly serious variety of acute liver failure for which no effective therapy has yet been developed. These Clinical Practice Guidelines summarize the available evidence on risk factors, diagnosis, management and risk minimization strategies for drug-induced liver jury.

Gynura Rhizoma containing pyrrolizidine alkaloids induces the hepatic sinusoidal obstruction syndrome in mice via upregulating fibrosis-related factors

Recently, hepatic sinusoidal obstruction syndrome (HSOS) caused by herbal preparations containing pyrrolizidine alkaloids (PAs), such as Gynura Rhizoma (Tusanqi), has gained global attention. However, the lack of a reliable and reproducible animal model has greatly hampered mechanistic studies. Therefore, we aimed to establish a reproducible HSOS mouse model and investigate the hepatotoxic mechanism. The model was established by intragastrical administration of Gynura Rhizoma extract, i.e., 1.0 g extract/kg per day (equal to 16.7 g crude drug/kg per day based on extraction rate and 49.1 mg PA/kg per day based on the total PA content in the extract determined) for 40 successive days. Then, the mice were sacrificed, and their blood samples and livers were collected for analyses. Using hematoxylin-eosin (HE) and Masson staining, scanning electron microscopy imaging, clinical biomarkers, and other assays, we showed that the HSOS was successfully induced in our mouse model. Furthermore, we detected the key factors involved in liver fibrosis in the mice, revealing significantly increased hydroxyproline concentration; elevated expression of α-smooth muscle actin (α-SMA) and fibrosis-related genes such as Collagen-1, Collagen-3, Mmp2, Mmp13, Timp1, Timp3, and Activin, upregulated Smad3 phosphorylation, and increased serum TGF-β levels. Moreover, pro-inflammatory cytokines, including Tnf-α, Il-1β, and Il-6, were also increased in the model. All these results demonstrate the key roles of the TGF-β-Smad3 and inflammatory signaling pathways in this Gynura Rhizoma-induced HSOS mouse model, suggesting that blockade of fibrosis and/or inflammation should be an effective treatment for HSOS.

Hepatobiliary Events in Migraine Therapy with Herbs-The Case of Petadolex, A Petasites Hybridus Extract

Petadolex^®, a defined butterbur extract has clinically proven efficacy against migraine attacks. However, spontaneous reports indicate cases of herbal induced liver injury (HILI). While most HILI patients presented mild serum biochemistry changes (<3 ULN, dose range 50 to 225 mg/day; treatment duration 4–730 days) nine developed severe HILI (average time-to-onset 103 days, ALT-range 3–153; AST 2–104-fold ULN). HILI cases resolved after medication withdrawal though two patients required liver transplantation. Liver biopsies revealed an inconsistent injury pattern, i.e. necrosis, macrovesicular steatosis, inflammation, cholestasis, and bile duct proliferation. Causality assessment rated 3 cases likely, 13 possible, 8 unlikely and 24 as unclassifiable/unclassified. Note, 22 patients reported hepatotoxic co-medications especially during periods of pain. A no-observable-adverse-effect-level at 15-fold of the maximal clinical dose (3 mg/kg/day MCD) was established for rats. At >45 and 90-fold MCD bile duct hyperplasia was observed but could not be confirmed in an explorative minipig study at 218-fold MCD. Human hepatocyte studies at 49-fold C_max serum petasins (=active ingredient) and therapeutic Ibuprofen, Paracetamol and Naratriptan concentrations evidenced liver transaminase and CYP-monooxygenase changes. Collectively, Petadolex^® HILI cases are rare, idiosyncratic and frequently confounded by co-medications. A physician-supervised self-medication plan with herbs and pain relief medication is needed to minimize risk for HILI.

Pyrrole-Hemoglobin Adducts, a More Feasible Potential Biomarker of Pyrrolizidine Alkaloid Exposure

Pyrrolizidine alkaloids (PAs) are naturally occurring phytotoxins widely distributed in about 3% of flowering plants. The formation of PA-derived pyrrole-protein adducts is considered as a primary trigger initiating PA-induced hepatotoxicity. The present study aims to (i) further validate our previous established derivatization method using acidified ethanolic AgNO₃ for the analysis of pyrrole-protein adducts and (ii) apply this method to characterize the binding tendency, dose-response, and elimination kinetics of pyrrole-protein adducts in blood samples. Two pyrrole-amino acid conjugates, (±)-6,7-dihydro-7-hydroxy-1-hydroxymethyl-5 H-pyrrolizine (DHP)-cysteine (7-cysteine-DHP) and 9-histidine-DHP, were synthesized and used to demonstrate that acidified ethanolic AgNO₃ derivatization can cleave both S-linkage and N-linkage of pyrrole-protein adducts. Subsequently, using precolumn AgNO₃ derivatization followed by ultra-high-pressure liquid chromatography/mass spectrometry analysis, we quantified pyrrole-protein adducts in monocrotaline-treated rat blood protein fractions, including hemoglobin (Hb), plasma, albumin, and plasma residual protein fractions, and found that the amount of pyrrole-Hb adducts was significantly higher than that in all plasma fractions. Moreover, elimination half-life of pyrrole-Hb adducts was also significantly longer than pyrrole-protein adducts in plasma fractions (12.08 vs 2.54-2.93 days). In addition, we also tested blood samples obtained from five PA-induced liver injury patients and found that the amount of pyrrole-protein adducts in blood cells was also remarkably higher than that in plasma. In conclusion, our findings for the first time confirmed that the AgNO₃ derivatization method could be used to measure both S- and N-linked pyrrole-protein adducts and also suggested that pyrrole-Hb adducts with remarkably higher level and longer life span could be a better biomarker of PA exposure.

Pyrrolizidine Alkaloids: Biosynthesis, Biological Activities and Occurrence in Crop Plants

Pyrrolizidine alkaloids (PAs) are heterocyclic secondary metabolites with a typical pyrrolizidine motif predominantly produced by plants as defense chemicals against herbivores. They display a wide structural diversity and occur in a vast number of species with novel structures and occurrences continuously being discovered. These alkaloids exhibit strong hepatotoxic, genotoxic, cytotoxic, tumorigenic, and neurotoxic activities, and thereby pose a serious threat to the health of humans since they are known contaminants of foods including grain, milk, honey, and eggs, as well as plant derived pharmaceuticals and food supplements. Livestock and fodder can be affected due to PA-containing plants on pastures and fields. Despite their importance as toxic contaminants of agricultural products, there is limited knowledge about their biosynthesis. While the intermediates were well defined by feeding experiments, only one enzyme involved in PA biosynthesis has been characterized so far, the homospermidine synthase catalyzing the first committed step in PA biosynthesis. This review gives an overview about structural diversity of PAs, biosynthetic pathways of necine base, and necic acid formation and how PA accumulation is regulated. Furthermore, we discuss their role in plant ecology and their modes of toxicity towards humans and animals. Finally, several examples of PA-producing crop plants are discussed.

Pyrrole-protein adducts - A biomarker of pyrrolizidine alkaloid-induced hepatotoxicity

Pyrrolizidine alkaloids (PAs) are phytotoxins identified in over 6000 plant species worldwide. Approximately 600 toxic PAs and PA N-oxides have been identified in about 3% flowering plants. PAs can cause toxicities in different organs particularly in the liver. The metabolic activation of PAs is catalyzed by hepatic cytochrome P450 and generates reactive pyrrolic metabolites that bind to cellular proteins to form pyrrole-protein adducts leading to PA-induced hepatotoxicity. The mechanisms that pyrrole-protein adducts induce toxicities have not been fully characterized. Methods for qualitative and quantitative detection of pyrrole-protein adducts have been developed and applied for the clinical diagnosis of PA exposure and PA-induced liver injury. This mini-review addresses the mechanisms of PA-induced hepatotoxicity mediated by pyrrole-protein adducts, the analytical methods for the detection of pyrrole-protein adducts, and the development of pyrrole-protein adducts as the mechanism-based biomarker of PA exposure and PA-induced hepatotoxicity.

Hepatic veno-occlusive disease related to Gynura segetum: A case report

INTRODUCTION

Hepatic veno-occlusive disease (HVOD), as known as hepatic sinusoidal obstruction syndrome (HSOS), is an obliterative venulitis of the terminal hepatic venules, which is responsible for considerable mortality. The potential mechanism is destruction of hepatic sinusoidal endothelial cells (SEC), with sloughing and downstream occlusion of terminal hepatic venules. Here, we report a case of HVOD who have a history of ingestion of Gynura segetum for 1 month. The patient presents for abdominal pain and distension. He was diagnosed for HVOD using computerized tomography (CT) and ultrasonography of liver. And then best supportive care was added. However, without liver transplantation for financial reason, he died in 1 month after discharged from hospital.

CONCLUSIONS

We think portal flow reversal was a characteristic imaging findings of HVOD, which can be listed as a specific diagnostic criterion of HVOD. Once the condition was worsening, liver transplantation should be considered as the first choice of treatment planning.

Toxic pyrrolizidine alkaloids provide a warning sign to overuse of the ethnomedicine Arnebia benthamii

ETHNOPHARMACOLOGICAL RELEVANCE

From early times man has used medicinal plants for the treatment of various ailments and basic health care needs. The use of herbal medicines has increased day by day and with this, so do reports of adverse events, poisoning, and suspected toxicity. Similarly, the indigenous communities of Neelum Valley in Azad Kashmir commonly use Arnebia benthamii (Wall. ex G.Don) I.M.Johnst. for medicinal purposes to treat various human aliments. Besides their medicinal uses, it also contains hepatotoxic pyrrolizidine alkaloids (PAs).

AIM OF THE STUDY

This explorative study underscores two major aspects about this herbal medicine. Firstly we aimed to document the traditional therapeutic uses of Arnebia benthamii in Neelum Valley, Azad Kashmir. Secondly, to determine the presence or absence of hepatotoxic pyrrolizidine alkaloids and if they are within the suggested limit for the use of herbs in excess.

MATERIALS AND METHODS

Interviews, group discussions, and inquiries were carried out from July to September 2016 with local indigenous and elder people. In the laboratory, the plant was investigated for pyrrolizidine alkaloids by using high performance liquid chromatography (HPLC).

RESULTS

A total of 30 respondents were interviewed. They explained the preferred preparation, parts used, and treatment indications. Treatment of fever along with kidney and liver problems are the three principle uses. Among the different parts of Arnebia benthamii, 43% respondents preferred aerial parts for the herbal formulation, followed by whole plants, and leaves. Decoction was the major mode of preparation and all herbal preparations were administrated orally. This study reports, for the first time according to our literature review, a study of Arnebia benthamii with regard to PA determination. By using column Zorbax SB-Aq and acetonitrile-water gradient as the mobile phase, HPLC results showed that the aerial parts of the plant were PA positive, and (1) Europine, Heliotrine (2), Lycopsamine (3), and Echimidine (4) were identified.

CONCLUSIONS

This study has revealed two new findings of significance to herbal medicine producers, practitioners, and consumers of Arnebia benthamii First, local knowledge regarding the medicinal uses of Arnebia benthamii were documented in five sites of Neelum Valley, Azad Kashmir. The use of this plant by a large part of the population in the study area shows the importance for their therapeutic benefits. Unfortunately, the second finding of this study shows that Arnebia benthamii contains hepatotoxic PAs. Hence, we advised to the government regulatory authorities and non-governmental organizations that use of this plant as herbal medicine should be excluded before more accurate quality control tests.

Integrative analysis of hepatic microRNA and mRNA to identify potential biological pathways associated with monocrotaline-induced liver injury in mice

Pyrrolizidine alkaloids (PAs) are a type of natural hepatotoxic compounds. Monocrotaline (MCT), belongs to PAs, is a main compound distributed in medicinal herb Crotalaria ferruginea Grah. ex Benth. This study aims to identify the potential biological signaling pathway associated with MCT-induced liver injury by analyzing the integrative altered hepatic microRNA (miRNA) and mRNA expression profile. C57BL/6 mice were orally given with MCT (270, 330mg/kg). Serum alanine/aspartate aminotransferase (ALT/AST) activity, total bilirubin (TBil) amount and liver histological evaluation showed the liver injury induced by MCT. Results of miRNA chip analysis showed that the hepatic expression of 15 miRNAs (whose signal intensity>200) was significantly altered in MCT-treated mice, and among them total 11 miRNAs passed further validation by using Real-time PCR assay. Results of mRNA chip analysis demonstrated that the hepatic expression of 569 genes was up-regulated and of other 417 genes was down-regulated in MCT-treated mice. There are total 426 predicted target genes of those above altered 11 miRNAs, and among them total 10 genes were also altered in mice treated with both MCT (270mg/kg) and MCT (330mg/kg) from the results of mRNA chip. Among these above 10 genes, total 8 genes passed further validation by using Real-time PCR assay. Only 1 biological signaling pathway was annotated by using those above 8 genes, which is phagosome. In conclusion, this study demonstrated the integrative altered expression profile of liver miRNA and mRNA, and identified that innate immunity may be critically involved in MCT-induced liver injury in mice.

Immunoassay approach for diagnosis of exposure to pyrrolizidine alkaloids

Numerous pyrrolizidine alkaloid (PA) poisoning cases have been documented worldwide. Protein covalent binding with reactive metabolites generated from metabolic activation of PAs to form pyrrole-protein adducts is suggested to be a primary mechanism of PA-induced toxicities. The present study aimed to develop antibodies for diagnosis of PA exposure. Polyclonal antibodies were raised in rabbits and proven to specifically recognize pyrrole-protein adducts regardless of amino acid residues modified by the reactive metabolites of PAs. The developed antibodies were successfully applied to detect pyrrole-protein adducts in blood samples obtained from PA-treated rats and exhibited a potential for the clinical diagnosis of PA exposure.

First evidence of pyrrolizidine alkaloid N-oxide-induced hepatic sinusoidal obstruction syndrome in humans

Pyrrolizidine alkaloids (PAs) are among the most potent phytotoxins widely distributed in plant species around the world. PA is one of the major causes responsible for the development of hepatic sinusoidal obstruction syndrome (HSOS) and exerts hepatotoxicity via metabolic activation to form the reactive metabolites, which bind with cellular proteins to generate pyrrole-protein adducts, leading to hepatotoxicity. PA N-oxides coexist with their corresponding PAs in plants with varied quantities, sometimes even higher than that of PAs, but the toxicity of PA N-oxides remains unclear. The current study unequivocally identified PA N-oxides as the sole or predominant form of PAs in 18 Gynura segetum herbal samples ingested by patients with liver damage. For the first time, PA N-oxides were recorded to induce HSOS in human. PA N-oxide-induced hepatotoxicity was further confirmed on mice orally dosed of herbal extract containing 170 μmol PA N-oxides/kg/day, with its hepatotoxicity similar to but potency much lower than the corresponding PAs. Furthermore, toxicokinetic study after a single oral dose of senecionine N-oxide (55 μmol/kg) on rats revealed the toxic mechanism that PA N-oxides induced hepatotoxicity via their biotransformation to the corresponding PAs followed by the metabolic activation to form pyrrole-protein adducts. The remarkable differences in toxicokinetic profiles of PAs and PA N-oxides were found and attributed to their significantly different hepatotoxic potency. The findings of PA N-oxide-induced hepatotoxicity in humans and rodents suggested that the contents of both PAs and PA N-oxides present in herbs and foods should be regulated and controlled in use.

Development and validation of a QuEChERS method coupled to liquid chromatography and high resolution mass spectrometry to determine pyrrolizidine and tropane alkaloids in honey

Awareness about pyrrolizidine alkaloids (PAs) and tropane alkaloids (TAs) in food was recently raised by the European Food Safety Authority stressing the lack of data and gaps of knowledge required to improve the risk assessment strategy. The present study aimed at the elaboration and validation of a method to determine PAs and TAs in honey. QuEChERS sample treatment and liquid chromatography coupled to hybrid high resolution mass spectrometry, were used. The method resulted in good linearity (R²>0.99) and low limits of detection and quantification, ranging from 0.04 to 0.2µgkg^-1 and from 0.1 to 0.7µgkg^-1 respectively. Recoveries ranged from 92.3 to 114.8% with repeatability lying between 0.9 and 15.1% and reproducibility between 1.1 and 15.6%. These performances demonstrate the selectivity and sensitivity of the method for simultaneous trace detection and quantification of PAs and TAs in honey, verified through the analysis of forty commercial samples.

Chlorogenic acid suppresses monocrotaline-induced sinusoidal obstruction syndrome: The potential contribution of NFκB, Egr1, Nrf2, MAPKs and PI3K signals

Hepatic sinusoidal obstruction syndrome (SOS) is a highly lethal liver disease. This study aims to observe the protection and its engaged mechanism of chlorogenic acid (CGA) against monocrotaline (MCT)-induced SOS. Results of detecting liver ascites, measuring serum transaminases, liver histological evaluation and scanning electron microscope observation all demonstrated that CGA prevented MCT-induced SOS in rats. CGA reduced MCT-induced increased liver myeloperoxidase (MPO) activity, tumor necrosis factor (TNF)α and interleukin (IL)-1β mRNA expression, toll-like receptor (TLR)-2,3,6,9 expression, and nuclear factor κB (NFκB) transcriptional activation. CGA also decreased MCT-induced early growth response1 (Egr1) activation. CGA reduced MCT-induced elevated liver malondialdehyde (MDA) amount and enhanced nuclear translocation of nuclear factor erythroid 2-related factor 2 (Nrf2). CGA blocked MCT-induced PI3K and MAPKs activation. In conclusion, this study demonstrates the protection of CGA against MCT-induced SOS. Transcriptional factor NFκB, Egr1 and Nrf2-regulated inflammation, coagulation-fibrinolysis, and antioxidant, and PI3K and MAPKs all contribute to such protection.

Blood Pyrrole-Protein Adducts--A Biomarker of Pyrrolizidine Alkaloid-Induced Liver Injury in Humans

Pyrrolizidine alkaloids (PAs) induce liver injury (PA-ILI) and is very likely to contribute significantly to drug-induced liver injury (DILI). In this study we used a newly developed ultra-high performance liquid chromatography-triple quadrupole-mass spectrometry (UHPLC-MS)-based method to detect and quantitate blood pyrrole-protein adducts in DILI patients. Among the 46 suspected DILI patients, 15 were identified as PA-ILI by the identification of PA-containing herbs exposed. Blood pyrrole-protein adducts were detected in all PA-ILI patients (100%). These results confirm that PA-ILI is one of the major causes of DILI and that blood pyrrole-protein adducts quantitated by the newly developed UHPLC-MS method can serve as a specific biomarker of PA-ILI.

Mass-spectrometry-directed analysis and purification of pyrrolizidine alkaloid cis/trans isomers in Gynura japonica

Pyrrolizidine alkaloids are highly hepatotoxic natural chemicals that produce irreversible chronic and acute hepatotoxic effects on human beings. Purification of large amounts of pyrrolizidine alkaloids is necessary for toxicity studies. In this study, an efficient method for targeted analysis and purification of pyrrolizidine alkaloid cis/trans isomers from herbal materials was developed for the first time. Targeted analysis of the hepatotoxic pyrrolizidine alkaloids was performed by liquid chromatography with tandem mass spectrometry (precursor ion scan and daughter ion scan), and the purification of pyrrolizidine alkaloids was achieved with a mass-directed auto purification system. The extraction and preparative liquid chromatography conditions were optimized. The developed method was applied to analysis of Gynura japonica (Thunb.) Juel., a herbal medicine traditionally used for detumescence and relieving pain but is potentially hepatotoxic as it contains pyrrolizidine alkaloids. Twelve pyrrolizidine alkaloids (six cis/trans isomer pairs) were identified with reference compounds or characterized by liquid chromatography with tandem mass spectrometry, and five individual pyrrolizidine alkaloids, including (E)-seneciphylline, seneciphylline, integerrimine, senecionine, and seneciphyllinine, were prepared from G. japonica roots with high efficiency. The results of this work provide a new technique for the preparation of large amounts of pyrrolizidine alkaloid reference substances, which will also benefit toxicological studies of pyrrolizidine alkaloids and treatments for pyrrolizidine alkaloid-induced toxicity.

Metabolomic and genomic evidence for compromised bile acid homeostasis by senecionine, a hepatotoxic pyrrolizidine alkaloid

Pyrrolizidine alkaloids (PAs) are among the most hepatotoxic natural products that produce irreversible injury to humans via the consumption of herbal medicine and honey, and through tea preparation. Toxicity and death caused by PA exposure have been reported worldwide. Metabolomics and genomics provide scientific and systematic views of a living organism and have become powerful techniques for toxicology research. In this study, senecionine hepatotoxicity on rats was determined via a combination of metabolomic and genomic analyses. From the global analysis generated from two omics data, the compromised bile acid homeostasis in vivo was innovatively demonstrated and confirmed. Serum profiling of bile acids was altered with significantly elevated conjugated bile acids after senecionine exposure, which was in accordance with toxicity. Similarly, the hepatic mRNA levels of several key genes associated with bile acid metabolism were significantly changed. This process included cholesterol 7-α hydroxylase, bile acid CoA-amino acid N-acetyltransferase, sodium taurocholate cotransporting polypeptide, organic anion-transporting polypeptides, and multidrug-resistance-associated protein 3. In conclusion, a cross-omics study provides a comprehensive analysis method for studying the toxicity caused by senecionine, which is a hepatotoxic PA. Moreover, the change in bile acid metabolism and the respective transporters may provide a new PA toxicity mechanism.

Assessment of pyrrolizidine alkaloid-induced toxicity in an in vitro screening model

ETHNOPHARMACOLOGICAL RELEVANCE

Pyrrolizidine alkaloids (PAs) are a group of heterocyclic phytotoxins present in a wide range of plants. The consumption of PA-containing medicinal herbs or PA-contaminated foodstuffs has long been reported to cause human hepatotoxicity. However, the degrees of hepatotoxicity of different PAs are unknown, which makes it difficult to determine a universal threshold of toxic dose of individual PAs for safe regulation of PA-containing natural products. The aim of the present study is to develop a simple and convenient in vitro model to assess the hepatotoxicity of different PAs.

MATERIAL AND METHODS

Six common cytotoxicity assays were used to evaluate the hepatotoxicity of different PAs in human hepatocellular carcinoma HepG2 cells.

RESULTS

The combination of MTT and bromodeoxyuridine incorporation (BrdU) assays demonstrated to be a suitable method to evaluate the toxic potencies of various PAs in HepG2 cells, and the results indicated that otonecine-type PA (clivorine: IC₂₀=0.013 ± 0.004 mM (MTT), 0.066 ± 0.031 mM (BrdU)) exhibited significantly higher cytotoxic and anti-proliferative effects than retronecine-type PA (retrorsine: IC₂₀=0.27 ± 0.07 mM (MTT), 0.19 ± 0.03 mM (BrdU)). While as expected, the known less toxic platyphylline-type PA (platyphylline: IC₂₀=0.85 ± 0.11 mM (MTT), 1.01 ± 0.40 mM (BrdU)) exhibited significantly less toxicity. The different cytotoxic and anti-proliferative potencies of various PAs in the same retronecine-type could also be discriminated by using the combined MTT and BrdU assays. In addition, the developed assays were further utilized to test alkaloid extract of Gynura segetum, a senecionine and seneciphylline-containing herb, the overall cytotoxicity of two PAs in the extract was comparable to that of these two PAs tested individually.

CONCLUSION

Using the developed in vitro model, the cytotoxicity of different PAs and the extract of a PA-containing herb were investigated in parallel in one system, and their different hepatotoxic potencies were determined and directly compared for the first time. The results suggested that the developed model has a great potential to be applied for the quick screening of the toxicity of PAs and PA-containing natural products.

Definitive diagnosis of hepatic sinusoidal obstruction syndrome induced by pyrrolizidine alkaloids

OBJECTIVE

Hepatic sinusoidal obstruction syndrome (HSOS) induced by a Chinese medicinal herb Tusanqi is increasingly being reported in recent years. The aim of the study was to investigate the possibility of using blood pyrrole-protein adducts test as a confirmatory diagnostic method.

METHODS

Patients with HSOS according to international diagnostic criteria associated with Tusanqi from January 2006 to August 2010 in Zhongshan Hospital Fudan University were included and clinical features were collected. Pyrrole-protein adducts in blood sample were determined with ultra performance liquid chromatography-mass spectrometry (UPLC-MS) while pyrrolizidine alkaloids (PAs) in available herbal preparations were analyzed by high performance liquid chromatography-ultraviolet (HPLC-UV).

RESULTS

Five patients (age 41-72 years, median age 54 years, all women) were included. Ascites (5/5), jaundice (5/5) and hepatomegaly (4/5) were common manifestations. The imaging features were diffused, patchy hepatic enhancement, periportal edema and ascites. Pathology ascertained that blood flow was obstructive at the site of sinusoid. PAs (Seneionine and seneciphylline) were identified in all the three available herbal preparations ingested by the HSOS patients. Pyrrole-protein adducts were unequivocally found in all the five blood samples. Two patients recovered, two developed chronic illness and one died due to liver failure and hepatic encephalopathy.

CONCLUSIONS

The detection of blood pyrrole-protein adducts using a UPLC-MS approach is a specific, reliable, unambiguous and confirmatory test for HSOS induced by PA, and should be used together with the conventional HSOS clinical diagnostic criteria for the definitive diagnosis of PA-induced HSOS.