Fatal acute arsenic poisoning by external use of realgar: Case report and 30 years literature retrospective study in China

Spotlight on the accumulation of heavy metals in Traditional Chinese medicines: A holistic view of pollution status, removal strategies and prospect

The accumulation of heavy metal in circulating TCMs has attracted widespread attention because the security and therapeutic efficacy are inevitably imperiled by the survival ecological environment and human production activities. How to reduce the pollution level and improve the toxicity damage becomes an urgent issue. This article provides a comprehensive overview of the current status of heavy metal contamination over a thousand types of single herbal (botanical, animal and mineral medicines) and TCM preparations published over nearly two decades. The survey revealed that growth ecosystems (soil, water sources), anthropogenic factors (harvesting, processing, storage), specific varieties and medicinal parts utilized as well as the inherent resistance capacity are the key factors that affect the accumulation of heavy metals in TCMs. And Pb, Cu and Cr are the major cumulative elements for botanicals, while mineral and animal medicines are dominated by As and Cu elements, respectively. Ongoing efforts aimed at mitigating the level and translocation rate of heavy metals by optimized cultivation processes, appropriate processing methodologies and advanced adsorption techniques are effective removal strategies. And the prospects of TCMs as a detoxifying agent for heavy metal toxicity damage posed development potential. Besides, the correlation between the speciation of arsenic (As) and chromium (Cr) and their toxicity should also be elaborated in order to provide effective references for standardizing drug dosage and cycle. And the imperative from the perspective of improving limitations standards of HMs for animal medicines, external preparations and folk medicines as well as exploring the interaction mechanisms between heavy metals and active ingredients of TCMs provides the direction for the follow-up study.

Lead and arsenic intoxications by traditional and alternative medicine: men are more sensitive than women

Traditional and alternative medicines are widely used around the world and include for example herbal medicine, Ayurveda, traditional Chinese medicine, and indigenous therapies. Due to the long history and the mostly natural origin of traditional remedies, it is often assumed that they are harmless, but in recent decades more and more case reports have been published in which traditional medicine has caused metal poisoning. This paper provides an analysis of published cases in which patients have suffered metal poisoning due to traditional or alternative medicines. A systematic literature search was performed on PubMed, whereby 210 patient cases from a total of 102 case reports and 30 case series were identified and then analyzed about various aspects. Most of the traditional medicines involved come from Asia and are mainly contaminated with lead and arsenic. The analyzed patient cases show a high degree of heterogeneity with regard to age, sex, intake reason, symptoms, and severity of intoxication. The metal intoxication itself and the cause of the poisoning often remained unrecognized for a long time, which resulted in many patients undergoing unnecessary diagnostic methods and ineffective therapeutic approaches before the correct diagnosis was made. The evaluation of the available patient cases revealed a higher sensitivity to metal poisoning in children compared to adults and a higher sensitivity in men compared to women. Anemia and basophilic stippling were frequently observed and became more common as the metal content in the blood increased. Hopefully, this paper raises awareness of the potential dangers of traditional and alternative medicines, both from the patient's and the doctor's perspective, so that in case of intoxication, treatment can be initiated quickly using the correct diagnostic methods. As ingested metals do not only circulate in the blood but also accumulate in soft tissues and bones, long-term monitoring is necessary to ensure that patients make a full recovery. Doctors should be aware that, in contrast to common belief, men are more sensitive to this type of intoxication than women, necessitating particular attention for diagnosis and treatment.

Four cases of fatal acute arsenic poisoning: histopathology, toxicology, and new trends

Arsenic is a valuable component in tumor treatment and traditional Chinese medicine and has seen widespread use in processing, manufacturing, and agriculture. Although rare, arsenic poisoning can occur in forensic practice. Elusive pathological changes, as well as obscure clinical signs, may cause arsenic poisoning to go unrecognized. Here, we report four cases of fatal acute arsenic poisoning, with careful observation of pathological changes and collection of postmortem specimens for arsenic concentration analysis. Additionally, we reviewed six cases of fatal arsenic poisoning in the past 20 years. In the present study, microvesicular steatosis in the peripheral areas of the hepatic lobules and acute splenitis were observed, which are rare findings in acute arsenic poisoning. This study summarizes the histopathological features of arsenic poisoning and presents data on arsenic distribution. Arsenic concentrations in the liver and kidneys can increase the reliability of identifying arsenic poisoning. Furthermore, in traditional Chinese medicine-related deaths, arsenic poisoning needs more attention.

Heavy metal poisoning caused by Chinese folk remedies in psoriasis patients: a retrospective analysis

Psoriasis, characterized as a chronic relapsing disease with a protracted course, often drives patients to seek relief through Chinese folk remedies (CFR). Nonetheless, the complex compositions of these remedies frequently result in unintended adverse effects, notably various types of heavy metal poisoning. Our study involved an exhaustive collection and analysis of clinical data from psoriasis patients who developed heavy metal poisoning due to CFR usage, admitted to Beijing Chao-Yang Hospital from January 2011 to October 2023. Our analysis identified 44 cases of mercury poisoning, 17 of lead poisoning, 21 of arsenic poisoning, and 4 instances of mixed heavy metal poisoning. The folk remedies used ranged from fumigation and inhalation to skin application and oral administration. Distinct pathogenic characteristics were observed in each poisoning type. After treatment with metal chelating agents, all patients experienced a reduction in heavy metal levels in their bodies, accompanied by varying degrees of symptom alleviation. This study underscores the vital necessity of opting for formal, medically approved treatments for psoriasis, thereby avoiding the hazardous consequences of unregulated folk remedies that may lead to severe heavy metal poisoning.

Realgar-Induced Neurotoxicity: Crosstalk Between the Autophagic Flux and the p62-NRF2 Feedback Loop Mediates p62 Accumulation to Promote Apoptosis

Realgar is a traditional Chinese medicine that contains arsenic. It has been reported that the abuse of medicine-containing realgar has potential central nervous system (CNS) toxicity, but the toxicity mechanism has not been elucidated. In this study, we established an in vivo realgar exposure model and selected the end product of realgar metabolism, DMA, to treat SH-SY5Y cells in vitro. Many assays, including behavioral, analytical chemistry, and molecular biology, were used to elucidate the roles of the autophagic flux and the p62-NRF2 feedback loop in realgar-induced neurotoxicity. The results showed that arsenic could accumulate in the brain, causing cognitive impairment and anxiety-like behavior. Realgar impairs the ultrastructure of neurons, promotes apoptosis, perturbs autophagic flux homeostasis, amplifies the p62-NRF2 feedback loop, and leads to p62 accumulation. Further analysis showed that realgar promotes the formation of the Beclin1-Vps34 complex by activating JNK/c-Jun to induce autophagy and recruit p62. Meanwhile, realgar inhibits the activities of CTSB and CTSD and changes the acidity of lysosomes, leading to the inhibition of p62 degradation and p62 accumulation. Moreover, the amplified p62-NRF2 feedback loop is involved in the accumulation of p62. Its accumulation promotes neuronal apoptosis by upregulating the expression levels of Bax and cleaved caspase-9, resulting in neurotoxicity. Taken together, these data suggest that realgar can perturb the crosstalk between the autophagic flux and the p62-NRF2 feedback loop to mediate p62 accumulation, promote apoptosis, and induce neurotoxicity. Realgar promotes p62 accumulation to produce neurotoxicity by perturbing the autophagic flux and p62-NRF2 feedback loop crosstalk.

Involvement of gut-brain communication in arsenite-induced neurobehavioral impairments in adult male mice

Arsenite is a well-documented neurotoxic metalloid that widely distributes in the natural environment. However, it remains largely unclear how arsenite affects neurological function. Therefore, in this study, the healthy adult male mice were exposed to 0.5 mg/L and 5 mg/L arsenite through drinking water for 30 and 90 days, respectively. Our results showed that there was no significant alteration in the intestine and brain for 30 days exposure, but exposure to arsenite for 90 days significantly induced a reduction of locomotor activity and anxiety-like behavior, caused pathological damage and inflammatory responses in the brain and intestine. We also found that arsenite remarkably disrupted intestinal barrier integrity, decreased the levels of lysozyme and digestive enzymes. Intriguingly, chronic exposure to arsenite significantly changed the levels of gut-brain peptides. Taken together, this study provides meaningful insights that gut-brain communication may involve in the neurobehavioral impairments of arsenite.

The safety of Chinese medicine: A systematic review of endogenous substances and exogenous residues

BACKGROUND

Safety and toxicity have become major challenges in the internationalization of Chinese medicine. Inspite of its wide application, security problems of Chinese medicine still occur from time to time, raising widespread concerns about its safety. Most of the studies either only partially discussed the intrinsic toxicities or extrinsic harmful residues in Chinese medicine, or briefly described detoxification and attenuation methods. It is necessary to systematically discuss Chinese medicine's extrinsic and intrinsic toxic components and corresponding toxicity detoxification or detection methods as a whole.

PURPOSE

This review comprehensively summarizes various toxic components in Chinese medicine from intrinsic and extrinsic. Then the corresponding methods for detoxification or detection of toxicity are highlighted. It is expected to provide a reference for safeguards for developing and using Chinese medicine.

METHODS

A literature search was conducted in the databases, including PubMed, Web of Science,Wan-fang database, and the China National Knowledge Infrastructure (CNKI). Keywords used were safety, toxicity, intrinsic toxicities, extrinsic harmful residues, alkaloids, terpene and macrolides, saponins, toxic proteins, toxic crystals, minerals, heavy metals, pesticides, mycotoxins, sulfur dioxide, detoxification, detection, processing (Paozhi), compatibility (Peiwu), Chinese medicine, etc., and combinations of these keywords. All selected articles were from 2006 to 2022, and each was assessed critically for our exclusion criteria. Studies describe the classification of toxic components of Chinese medicine, the toxic effects and mechanisms of Chinese medicine, and the corresponding methods for detoxification or detection of toxicity.

RESULTS

The toxic components of Chinese medicines can be classified as intrinsic toxicities and extrinsic harmful residues. Firstly, we summarized the intrinsic toxicities of Chinese medicine, the adverse effects and toxicity mechanisms caused by these components. Next, we focused on the detoxification or attenuation methods for intrinsic toxicities of Chinese medicine. The other main part discussed the latest progress in analytical strategies for exogenous hazardous substances, including heavy metals, pesticides, and mycotoxins. Beyond reviewing mainstream instrumental methods, we also introduced the emerging biochip, biosensor and immuno-based techniques.

CONCLUSION

In this review, we provide an overall assessment of the recent progress in endogenous toxins and exogenous hazardous substances concerning Chinese medicine, which is expected to render deeper insights into the safety of Chinese medicine.

A Metabolic Profiling Study of Realgar-Induced Acute Kidney Injury in Mice

Realgar has been used as a type of mineral drug that contains arsenic for thousands of years. Previous studies have shown that Realgar-induced acute kidney injury is associated with abnormal metabolism, but the underlying mechanism is poorly understood. The aim of this study is to investigate the metabolic changes in serum and kidney tissues of mice exposed to Realgar by using a metabolomic approach and explore the molecular mechanisms of acute kidney injury induced by Realgar. Forty mice were randomly divided into four groups: Control group, 0.5-, 1.0, and 2.0 g/kg Realgar group. After 1 week, the body weight and kidney weight of the mice were measured. The serum and kidney samples were used for LC-MS spectroscopic metabolic profiling. Principal component analysis (PCA), correlation analysis, and pathway analysis were used to detect the nephrotoxic effects of Realgar. Body weight decreased significantly in the 2.0 g/kg group, and the kidney weight index also showed a dose-dependent increase in Realgar. The PCA score plot showed the serum and kidney tissue metabolic profile of mice exposed to 2.0 g/kg Realgar separated from the control group, while the lower-doses of 0.5 g/kg and 1.0 g/kg Realgar shown a similar view to the Control group. Thirty-three metabolites and seventeen metabolites were screened and identified in the serum and kidney of mice in a dose-dependent manner. respectively. Correlation analysis showed a strong correlation among these metabolites. Amino acid metabolism, lipid metabolism, glutathione metabolism, and purine metabolism pathways were found to be mainly associated with Realgar nephrotoxicity. This work illustrated the metabolic alterations in Realgar-induced nephrotoxic mice through a metabolomic approach.

Proteomics analysis in the kidney of mice following oral feeding Realgar

ETHNOPHARMACOLOGICAL RELEVANCE

Realgar, a famous traditional Chinese mineral medicine, has been toxic to the renal system. However, the underlying mechanism of Realgar nephrotoxicity is still unclear.

AIM OF THE STUDY

This study aimed to investigate the potential mechanism of Realgar-induced nephrotoxicity by using a label-free quantitative proteomic method.

MATERIALS AND METHODS

36 mice were randomly divided into four groups: Control group, 0.5-, 1.0, and 2.0 g/kg Realgar group. After one week, serum biochemical parameters and renal histopathological examination were performed. Label-free quantitative proteomics was used to identify differentially expressed proteins which were subsequently analyzed with bioinformatics methods. Western blot was utilized to verify the six representative protein expressions.

RESULTS

The results showed that 2.0 g/kg Realgar significantly increased blood urea nitrogen and induced the formation of tube cast of renal tubules, while the lower-dose of 0.5 g/kg and 1.0 g/kg Realgar showed no changes. Label-free proteomic analysis identified 3138 proteins, and 272 of those proteins were screened for significant changes in a dose-dependent manner. Functional enrichment analysis suggested that these proteins could affect the apoptotic process and oxidative stress. Representative proteins in the 2.0 g/kg Realgar group, including Cat, Bad, Cycs, Nqo1, Podxl, and Hmox1, were verified by western blot.

CONCLUSIONS

The results in this study suggest that apoptosis and oxidative stress might be related to the Realgar-induced nephrotoxicity in mice. Moreover, the strategy of proteomics could contribute to the understanding of the mechanisms of nephrotoxicity in mice exposed to Realgar.

Health risks from groundwater arsenic on residents in northern China coal-rich region

Shanxi Province of northern China is a typical mining concentration and arsenism area. Years of mining activities have resulted in serious regional groundwater problems in Shanxi. Therefore, it is of great significance to know the health risk of groundwater arsenic on residents under the background of mining activities. Kriging interpolation was used to illustrate the spatio-temporal dynamics of the health risks on groundwater arsenic based on a ten-year investigation. The groundwater arsenic concentrations decreased over time and the distribution of high arsenic concentrations shrank. High arsenic concentrations were mainly distributed in the northern and middle basin areas. The forecasted area of high risks in coal mining areas was 5623 km², which was larger than that in non-coal mining areas. The residents living around mining areas were more vulnerable to exposure to groundwater arsenic. Further, the output map outlines the high-risk zones in order to protect the safety of drinking water for residents. This study may be helpful for the policy-makers to adopt a lower limit for groundwater arsenic to the worst affected regions and groups.

Clinical Application and Efficacy of Silver Drug in Ophthalmology: A Literature Review and New Formulation of EYE Drops with Drug Silver (I) Complex of Metronidazole with Improved Dosage Form

The use of silver preparations in medicine is becoming increasingly popular. The basic aim of this evaluation was to review the literature on the clinical (in vivo) and antibacterial potential of silver preparations in ophthalmic diseases. The second goal was to summarize the results of experimental research on the use of silver preparations in ophthalmology. The third objective was to present a method for stabilizing eye drops containing silver (I) complex. Analysis of the pH stability of the silver (I) complex with metronidazole in the prepared dosage form (eye drops) was carried out. Most silver preparations are clinically used for topical application. Few experimental results indicate the usefulness of intraocular or systemic administration of silver (I) preparations as an alternative or additional therapy in infectious and angiogenic eye diseases. The development of a new formulation increases the stability of the dosage form. New forms of silver (I) products will certainly find application in the treatment of many ophthalmic diseases. One of the most important features of the silver (I) complex is its capacity to break down bacterial resistance. The new eye drops formula can significantly improve comfort of use. Due to their chemical nature, silver (I) compounds are difficult to stabilize, especially in the finished dosage form.

Ectopic expression of wheat aquaglyceroporin TaNIP2;1 alters arsenic accumulation and tolerance in Arabidopsis thaliana

Arsenic (As) is one of the most toxic contaminants to food crops, and as such, decreasing crops uptake and accumulation of As cannot be overemphasized. Here, we characterized a functional wheat NIP2;1 homolog of the As transporter, TaNIP2;1. TaNIP2;1 expression was suppressed by arsenite (As(III)) in wheat. Ectopic expression of TaNIP2;1 in the Δfps1 yeast mutant enhanced yeast sensitivity towards As(III). Conversely, the elevated expression of TaNIP2;1 in Δacr3 mutants decreased yeast sensitivity to arsenate (As(V)), demonstrating that TaNIP2;1 showed both influx and efflux transport activities for As(III) in yeasts. This is further supported by increased As concentration in the yeast cells that overproduce TaNIP2;1 in Δfps1, while As concentration decreased in Δacr3. Furthermore, ectopic expression of TaNIP2;1 in Arabidopsis confirmed that TaNIP2;1 can transport As into plants, as supported by increased sensitivity to and uptake of As(III). No change in plant sensitivity was found to Cu(II), Cd(II), Zn(II) or Ni(II), indicating that transport activity of TaNIP2;1 is specific for As(III). Taken together, our data show that TaNIP2;1 may be involved in As(III) transportation in plants. This finding reveals a functional gene that can be manipulated to reduce As content in wheat.

Arsenic Accumulation of Realgar Altered by Disruption of Gut Microbiota in Mice

Objective

To investigate the influence of gut microbiota on arsenic accumulation of realgar in mice.

Methods

Mice were treated with antibiotics to form a mouse model of gut microbial disruption. Antibiotic-treated and normally raised mice were given 15 mg/kg, 150 mg/kg, and 750 mg/kg realgar by gavage and 0.2 mg/kg and 1 mg/kg arsenic solution by subcutaneous injection for 7 days. The concentration of arsenic in mice whole blood was determined by inductively coupled plasma mass spectrometry (ICP-MS). Arsenic accumulation in antibiotic-treated mice and normally raised mice was compared.

Results

After exposure to low dose (15 mg/kg) and middle dose (150 mg/kg) of realgar, significantly, more arsenic was accumulated in the whole blood of antibiotic-treated mice compared to normally raised counterparts, which indicated that the disruption of gut microbiota could lead to higher arsenic load of realgar in mice. The homeostasis of gut microbiota was supposed to be disrupted by high dose (750 mg/kg) of realgar because after exposure to high dose of realgar, there was no significant difference in arsenic accumulation between antibiotic-treated and normally raised mice. Furthermore, arsenic solution was administered by subcutaneous injection to mice to investigate the influence of gut microbial differences on arsenic accumulation in addition to the absorption process, and there was no significant difference in arsenic accumulation between mice with these two different statuses of gut microbiota.

Conclusions

Gut microbiota disruption could increase arsenic accumulation of realgar in mice.

Arsenic intoxication: general aspects and chelating agents

Arsenic (As) is widely used in the modern industry, especially in the production of pesticides, herbicides, wood preservatives, and semiconductors. The sources of As such as contaminated water, air, soil, but also food, can cause serious human diseases. The complex mechanism of As toxicity in the human body is associated with the generation of free radicals and the induction of oxidative damage in the cell. One effective strategy in reducing the toxic effects of As is the usage of chelating agents, which provide the formation of inert chelator–metal complexes with their further excretion from the body. This review discusses different aspects of the use of metal chelators, alone or in combination, in the treatment of As poisoning. Consideration is given to the therapeutic effect of thiol chelators such as meso-2,3-dimercaptosuccinic acid, sodium 2,3-dimercapto-1-propanesulfonate, 2,3-dimercaptopropanol, penicillamine, ethylenediaminetetraacetic acid, and other recent agents against As toxicity. The review also considers the possible role of flavonoids, trace elements, and herbal drugs as promising natural chelating and detoxifying agents.

Identification of neurotoxicity markers induced by realgar exposure in the mouse cerebral cortex using lipidomics

Realgar is a traditional Chinese medicine containing arsenic and has neurotoxicity. This study used realgar exposure mice model, neurobehavioral tests, analytical chemistry, molecular biology and nontargeted lipidomics to explore the mechanism of realgar damages the nervous system. The arsenic contained in realgar passed through the BBB and accumulated in the brain. Neurons, synapses and myelin showed abnormal changes in the cerebral cortex. The number of autophagosomes were incresed as well as levels of MDA, Lp-PLA2, and cPLA2 but the CAT level was significant reduced. Finally, the cognition and memory of mice were decreased. Nontargeted lipidomics detected 34 lipid subclasses including 1603 lipid molecules. The levels of the LPC and LPE were significantly increased. Under the condition of variable importance for the projection (VIP)>1 and P < 0.05, only 28 lipid molecules satisfied the criteria. The lipid molecular markers SM (d36:2), PE (18:2/22:6) and PE (36:3) which were filtered by receiver operating characteristic (ROC) curve (AUC>0.8 or AUC<0.2) were used to identify the neurotoxicity induced by realgar. Therefore, realgar induces neurotoxicity through exacerbating oxidative damage and lipid dysfunction. Providing research basis for the clinical diagnosis and treatment of realgar-induced neurotoxicity.