Paracetamol (acetaminophen) overdose and hepatotoxicity: mechanism, treatment, prevention measures, and estimates of burden of disease

Paeonia lactiflora Pall. ameliorates acetaminophen-induced oxidative stress and apoptosis via inhibiting the PKC-ERK pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Paeonia lactiflora Pall. (PLP), a traditional Chinese medicine, is recognized for its antioxidative and anti-apoptotic properties. Despite its potential medicinal value, the mechanisms underlying its efficacy have been less explored, particularly in alleviating acute liver injury (ALI) caused by excessive intake of acetaminophen (APAP).

AIM OF THE STUDY

This study aims to elucidate the role and mechanisms of PLP in mitigating oxidative stress and apoptosis induced by APAP.

MATERIALS AND METHODS

C57BL/6 male mice were pre-treated with PLP for seven consecutive days, followed by the induction of ALI using APAP. Liver pathology was assessed using HE staining. Serum indicators, immunofluorescence (IF), immunohistochemical (IHC), and transmission electron microscopy were employed to evaluate levels of oxidative stress, ferroptosis and apoptosis. Differential expression proteins (DEPs) in the APAP-treated and PLP pre-treated groups were analyzed using quantitative proteomics. Subsequently, the potential mechanisms of PLP pre-treatment in treating ALI were validated using western blotting, molecular docking, molecular dynamics simulations, and surface plasmon resonance (SPR) analysis.

RESULTS

The UHPLC assay confirmed the presence of three compounds, i.e., albiflorin, paeoniflorin, and oxypaeoniflorin. Pre-treatment with PLP was observed to ameliorate liver tissue pathological damage through HE staining. Further confirmation of efficacy of PLP in alleviating APAP-induced liver injury and oxidative stress was established through liver function serum biochemical indicators, IF of reactive oxygen species (ROS) and IHC of glutathione peroxidase 4 (GPX4) detection. However, PLP did not demonstrate a significant effect in alleviating APAP-induced ferroptosis. Additionally, transmission electron microscopy and TUNEL staining indicated that PLP can mitigate hepatocyte apoptosis. PKC-ERK pathway was identified by proteomics, and subsequent molecular docking, molecular dynamics simulations, and SPR verified binding of the major components of PLP to ERK protein. Western blotting demonstrated that PLP suppressed protein kinase C (PKC) phosphorylation, blocking extracellular signal-regulated kinase (ERK) phosphorylation and inhibiting oxidative stress and cell apoptosis.

CONCLUSION

This study demonstrates that PLP possesses hepatoprotective abilities against APAP-induced ALI, primarily by inhibiting the PKC-ERK cascade to suppress oxidative stress and cell apoptosis.

A Review of the Role of Caveolin-1 in Acetaminophen-Induced Liver Injury

BACKGROUND

Acetaminophen (APAP) is commonly used as an antipyretic and analgesic agent. Excessive APAP can induce liver toxicity, known as APAP-induced liver injury (ALI). The metabolism and pathogenesis of APAP have been extensively studied in recent years, and many cellular processes such as autophagy, mitochondrial oxidative stress, mitochondrial dysfunction, and liver regeneration have been identified to be involved in the pathogenesis of ALI. Caveolin-1 (CAV-1) as a scaffold protein has also been shown to be involved in the development of various diseases, especially liver disease and tumorigenesis. The role of CAV-1 in the development of liver disease and the association between them remains a challenging and uncharted territory.

SUMMARY

In this review, we briefly explore the potential therapeutic effects of CAV-1 on ALI through autophagy, oxidative stress, and lipid metabolism. Further research to better understand the mechanisms by which CAV-1 regulates liver injury will not only enhance our understanding of this important cellular process, but also help develop new therapies for human disease by targeting CAV-1 targets.

KEY MESSAGES

This review briefly summarizes the potential protective mechanisms of CAV-1 against liver injury caused by APAP.

Unveiling the Potential of Cannabinoids in Multiple Sclerosis and the Dawn of Nano-Cannabinoid Medicine

Multiple sclerosis is the predominant autoimmune disorder affecting the central nervous system in adolescents and adults. Specific treatments are categorized as disease-modifying, whereas others are symptomatic treatments to alleviate painful symptoms. Currently, no singular conventional therapy is universally effective for all patients across all stages of the illness. Nevertheless, cannabinoids exhibit significant promise in their capacity for neuroprotection, anti-inflammation, and immunosuppression. This review will examine the traditional treatment for multiple sclerosis, the increasing interest in using cannabis as a treatment method, its role in protecting the nervous system and regulating the immune system, commercially available therapeutic cannabinoids, and the emerging use of cannabis in nanomedicine. In conclusion, cannabinoids exhibit potential as a disease-modifying treatment rather than merely symptomatic relief. However, further research is necessary to unveil their role and establish the safety and advancements in nano-cannabinoid medicine, offering the potential for reduced toxicity and fewer adverse effects, thereby maximizing the benefits of cannabinoids.

Inhibition of Adult Neurogenesis in Male Mice after Repeated Exposure to Paracetamol Overdose

Paracetamol, or acetaminophen (N-acetyl-para-aminophenol, APAP), is an analgesic and antipyretic drug that is commonly used worldwide, implicated in numerous intoxications due to overdose, and causes serious liver damage. APAP can cross the blood-brain barrier and affects brain function in numerous ways, including pain signals, temperature regulation, neuroimmune response, and emotional behavior; however, its effect on adult neurogenesis has not been thoroughly investigated. We analyze, in a mouse model of hepatotoxicity, the effect of APAP overdose (750 mg/kg/day) for 3 and 4 consecutive days and after the cessation of APAP administration for 6 and 15 days on cell proliferation and survival in two relevant neurogenic zones: the subgranular zone of the dentate gyrus and the hypothalamus. The involvement of liver damage (plasma transaminases), neuronal activity (c-Fos), and astroglia (glial fibrillar acidic protein, GFAP) were also evaluated. Our results indicated that repeated APAP overdoses are associated with the inhibition of adult neurogenesis in the context of elevated liver transaminase levels, neuronal hyperactivity, and astrogliosis. These effects were partially reversed after the cessation of APAP administration for 6 and 15 days. In conclusion, these results suggest that APAP overdose impairs adult neurogenesis in the hippocampus and hypothalamus, a fact that may contribute to the effects of APAP on brain function.

High-throughput screening of novel TFEB agonists in protecting against acetaminophen-induced liver injury in mice

Macroautophagy (referred to as autophagy hereafter) is a major intracellular lysosomal degradation pathway that is responsible for the degradation of misfolded/damaged proteins and organelles. Previous studies showed that autophagy protects against acetaminophen (APAP)-induced injury (AILI) via selective removal of damaged mitochondria and APAP protein adducts. The lysosome is a critical organelle sitting at the end stage of autophagy for autophagic degradation via fusion with autophagosomes. In the present study, we showed that transcription factor EB (TFEB), a master transcription factor for lysosomal biogenesis, was impaired by APAP resulting in decreased lysosomal biogenesis in mouse livers. Genetic loss-of and gain-of function of hepatic TFEB exacerbated or protected against AILI, respectively. Mechanistically, overexpression of TFEB increased clearance of APAP protein adducts and mitochondria biogenesis as well as SQSTM1/p62-dependent non-canonical nuclear factor erythroid 2-related factor 2 (NRF2) activation to protect against AILI. We also performed an unbiased cell-based imaging high-throughput chemical screening on TFEB and identified a group of TFEB agonists. Among these agonists, salinomycin, an anticoccidial and antibacterial agent, activated TFEB and protected against AILI in mice. In conclusion, genetic and pharmacological activating TFEB may be a promising approach for protecting against AILI.

NLRP3 inflammasome in hepatic diseases: A pharmacological target

The NOD-like receptor family pyrin domain containing 3 (NLRP3) inflammasome pathway is mainly responsible for the activation and release of a cascade of proinflammatory mediators that contribute to the development of hepatic diseases. During alcoholic liver disease development, the NLRP3 inflammasome pathway contributes to the maturation of caspase-1, interleukin (IL)-1β, and IL-18, which induce a robust inflammatory response, leading to fibrosis by inducing profibrogenic hepatic stellate cell (HSC) activation. Substantial evidence demonstrates that nonalcoholic fatty liver disease (NAFLD) progresses to nonalcoholic steatohepatitis (NASH) via NLRP3 inflammasome activation, ultimately leading to fibrosis and hepatocellular carcinoma (HCC). Activation of the NLRP3 inflammasome in NASH can be attributed to several factors, such as reactive oxygen species (ROS), gut dysbiosis, leaky gut, which allow triggers such as cardiolipin, cholesterol crystals, endoplasmic reticulum stress, and uric acid to reach the liver. Because inflammation triggers HSC activation, the NLRP3 inflammasome pathway performs a central function in fibrogenesis regardless of the etiology. Chronic hepatic activation of the NLRP3 inflammasome can ultimately lead to HCC; however, inflammation also plays a role in decreasing tumor growth. Some data indicate that NLRP3 inflammasome activation plays an important role in autoimmune hepatitis, but the evidence is scarce. Most researchers have reported that NLRP3 inflammasome activation is essential in liver injury induced by a variety of drugs and hepatotropic virus infection; however, few reports indicate that this pathway can play a beneficial role by inducing liver regeneration. Modulation of the NLRP3 inflammasome appears to be a suitable strategy to treat liver diseases.

6-Hydroxy-2,2,4-trimethyl-1,2-dihydroquinoline Demonstrates Anti-Inflammatory Properties and Reduces Oxidative Stress in Acetaminophen-Induced Liver Injury in Rats

We examined the effects of 6-hydroxy-2,2,4-trimethyl-1,2-dihydroquinoline on markers of liver injury, oxidative status, and the extent of inflammatory and apoptotic processes in rats with acetaminophen-induced liver damage. The administration of acetaminophen caused the accumulation of 8-hydroxy-2-deoxyguanosine and 8-isoprostane in the liver and serum, as well as an increase in biochemiluminescence indicators. Oxidative stress resulted in the activation of pro-inflammatory cytokine and NF-κB factor mRNA synthesis and increased levels of immunoglobulin G, along with higher activities of caspase-3, caspase-8, and caspase-9. The administration of acetaminophen also resulted in the development of oxidative stress, leading to a decrease in the level of reduced glutathione and an imbalance in the function of antioxidant enzymes. This study discovered that 6-hydroxy-2,2,4-trimethyl-1,2-dihydroquinoline reduced oxidative stress by its antioxidant activity, hence reducing the level of pro-inflammatory cytokine and NF-κB mRNA, as well as decreasing the concentration of immunoglobulin G. These changes resulted in a reduction in the activity of caspase-8 and caspase-9, which are involved in the activation of ligand-induced and mitochondrial pathways of apoptosis and inhibited the effector caspase-3. In addition, 6-hydroxy-2,2,4-trimethyl-1,2-dihydroquinoline promoted the normalization of antioxidant system function in animals treated with acetaminophen. As a result, the compound being tested alleviated inflammation and apoptosis by decreasing oxidative stress, which led to improved liver marker indices and ameliorated histopathological alterations.