Clinical and experimental research in antituberculosis drug-induced hepatotoxicity: a review

Silymarin: Unveiling its pharmacological spectrum and therapeutic potential in liver diseases-A comprehensive narrative review

Liver diseases, encompassing conditions such as cirrhosis, present a substantial global health challenge with diverse etiologies, including viral infections, alcohol consumption, and non-alcoholic fatty liver disease (NAFLD). The exploration of natural compounds as therapeutic agents has gained traction, notably the herbal remedy milk thistle (Silybum marianum), with its active extract, silymarin, demonstrating remarkable antioxidant and hepatoprotective properties in extensive preclinical investigations. It can protect healthy liver cells or those that have not yet sustained permanent damage by reducing oxidative stress and mitigating cytotoxicity. Silymarin, a natural compound with antioxidant properties, anti-inflammatory effects, and antifibrotic activity, has shown potential in treating liver damage caused by alcohol, NAFLD, drug-induced toxicity, and viral hepatitis. Legalon® is a top-rated medication with excellent oral bioavailability, effective absorption, and therapeutic effectiveness. Its active component, silymarin, has antioxidant and hepatoprotective properties, Eurosil 85® also, a commercial product, has lipophilic properties enhanced by special formulation processes. Silymarin, during clinical trials, shows potential improvements in liver function, reduced mortality rates, and alleviation of symptoms across various liver disorders, with safety assessments showing low adverse effects. Overall, silymarin emerges as a promising natural compound with multifaceted hepatoprotective properties and therapeutic potential in liver diseases.

Hepatoprotective potential of diosmin against hepatotoxic effect of isoniazid and rifampin in wistar rats

OBJECTIVE

The treatment of tuberculosis with isoniazid and rifampin is associated with hepatocellular damage. Therefore, the study was designed to evaluate the hepatoprotective potential of diosmin against hepatotoxic effect of isoniazid and rifampin in Wistar rats.

METHODS

Hepatotoxicity was induced by administering isoniazid and rifampin (100 mg/kg), whereas diosmin was given as treatment control. Markers of liver function (ALT, AST, ALP and bilirubin), inflammatory cytokines (TNFα, IL-6 and IL-1β), apoptosis (caspase-3), oxidative stress parameters (LPO, GSH, CAT and SOD) and histological changes in liver were assessed in normal, hepatotoxic control and treatment groups.

RESULTS

The administration of isoniazid and rifampin significantly increased markers of liver dysfunction (ALT, AST, ALP and bilirubin), cytokines (TNFα, IL-6 and IL-1β) and apoptosis (caspase-3). However, daily dosing of diosmin significantly reduced these markers of liver dysfunction, inflammatory cytokines and apoptosis to near normal levels. Additionally, markers of hepatocellular oxidative stress parameters were significantly altered as evident from increased LPO level and decreased endogenous antioxidants such as GSH, SOD and CAT in isoniazid-and rifampin-treated hepatotoxic group. It was observed that diosmin treatment reduced high levels of LPO and demonstrated significant improvement in antioxidant levels. Histological studies of liver also supported our biochemical findings, which are also manifested as diosmin treatment exhibited protection against hepatocellular degeneration and inflammation.

CONCLUSION

Results of the present study demonstrate hepatoprotective potential of diosmin against isoniazid-and rifampin-treated hepatotoxicity. Thus, we conclude that diosmin may be used along with anti-tubercular drugs (isoniazid and rifampin) in tuberculosis patients to overcome their hepatotoxic adverse effect.

Genetic polymorphism related to ethambutol outcomes and susceptibility to toxicity

The World Health Organization (WHO) stated that ensuring access to effective and optimal treatment is a key component to eradicate tuberculosis (TB) through the End TB Strategy. Personalized medicine that depends on the genetic profile of an individual is one way to optimize treatment. It is necessary because of diverse drug responses related to the variation in human DNA, such as single-nucleotide polymorphisms (SNPs). Ethambutol (EMB) is a drug widely used as the treatment for Mycobacterium Tuberculosis (Mtb) and/non-tuberculous mycobacteria and has become a potential supplementary agent for a treatment regimen of multidrug-resistant (MDR) and extensively drug-resistant (XDR) TB. In human genetic polymorphism studies of anti-tuberculosis, the majority focus on rifampicin or isoniazid, which discuss polymorphisms related to their toxicity. Whereas there are few studies on EMB, the incidence of EMB toxicity is lower than that of other first-line anti-TB drugs. To facilitate personalized medicine practice, this article summarizes the genetic polymorphisms associated with alterations in the pharmacokinetic profile, resistance incidence, and susceptibility to EMB toxicity. This study includes 131 total human studies from 17 articles, but only eight studies that held in the low-middle income country (LMIC), while the rest is research conducted in developed countries with high incomes. Personalized medicine practices are highly recommended to maintain and obtain the optimal therapeutic effect of EMB.

Effects of medium- and long-chain fatty acids on acetaminophen- or rifampicin-induced hepatocellular injury

Drug-induced liver injury (DILI) is one of the common adverse effects of drug therapy, which is closely associated with oxidative stress, apoptosis, and inflammation response. Medium-chain fatty acids (MCFA) were reported to relieve inflammation and attenuate oxidative stress. However, little has been known about the hepatoprotective effects of MCFA in DILI. In the present study, acetaminophen (AP) and rifampicin (RFP) were used to establish DILI models in LO2 cells, and the cytoprotective effects of MCFA on hepatocellular injury were investigated. Results showed that the optimal condition for the DILI model was treatment with 10 mM AP or 600 µM RFP for 24 hr. LCFA treatment markedly reduced the cell viability and increased the activities of alanine aminotransferase, aspartate aminotransferase, and lactate dehydrogenase. Meanwhile, LCFA treatment aggravated cell apoptosis, mitochondrial dysfunction, and oxidative stress. The mRNA and protein expression levels of inflammatory cytokines (IL-1β and TNF-α) were significantly elevated by LCFA. In contrast, MCFA treatment did not significantly affect cell viability, apoptosis, oxidative, stress and inflammation, and it did not produce the detrimental effects on DILI models. Therefore, we proposed that MCFA may be more safe and suitable than LCFA as nutrition support or the selection of daily dietary oil and fat for the patients with DILI.

Silymarin as Supportive Treatment in Liver Diseases: A Narrative Review

Silymarin, an extract from milk thistle seeds, has been used for centuries to treat hepatic conditions. Preclinical data indicate that silymarin can reduce oxidative stress and consequent cytotoxicity, thereby protecting intact liver cells or cells not yet irreversibly damaged. Eurosil 85® is a proprietary formulation developed to maximize the oral bioavailability of silymarin. Most of the clinical research on silymarin has used this formulation. Silymarin acts as a free radical scavenger and modulates enzymes associated with the development of cellular damage, fibrosis and cirrhosis. These hepatoprotective effects were observed in clinical studies in patients with alcoholic or non-alcoholic fatty liver disease, including patients with cirrhosis. In a pooled analysis of trials in patients with cirrhosis, silymarin treatment was associated with a significant reduction in liver-related deaths. Moreover, in patients with diabetes and alcoholic cirrhosis, silymarin was also able to improve glycemic parameters. Patients with drug-induced liver injuries were also successfully treated with silymarin. Silymarin is generally very well tolerated, with a low incidence of adverse events and no treatment-related serious adverse events or deaths reported in clinical trials. For maximum benefit, treatment with silymarin should be initiated as early as possible in patients with fatty liver disease and other distinct liver disease manifestations such as acute liver failure, when the regenerative potential of the liver is still high and when removal of oxidative stress, the cause of cytotoxicity, can achieve the best results.

Niosome-Based Approach for In Situ Gene Delivery to Retina and Brain Cortex as Immune-Privileged Tissues

Non-viral vectors have emerged as a promising alternative to viral gene delivery systems due to their safer profile. Among non-viral vectors, recently, niosomes have shown favorable properties for gene delivery, including low toxicity, high stability, and easy production. The three main components of niosome formulations include a cationic lipid that is responsible for the electrostatic interactions with the negatively charged genetic material, a non-ionic surfactant that enhances the long-term stability of the niosome, and a helper component that can be added to improve its physicochemical properties and biological performance. This review is aimed at providing recent information about niosome-based non-viral vectors for gene delivery purposes. Specially, we will discuss the composition, preparation methods, physicochemical properties, and biological evaluation of niosomes and corresponding nioplexes that result from the addition of the genetic material onto their cationic surface. Next, we will focus on the in situ application of such niosomes to deliver the genetic material into immune-privileged tissues such as the brain cortex and the retina. Finally, as future perspectives, non-invasive administration routes and different targeting strategies will be discussed.

Protective effect of pyrrolidine dithiocarbamate on isoniazid/rifampicin‑induced liver injury in rats

Isoniazid (INH) and rifampicin (RIF) continue to be first line anti‑tuberculosis (TB) drugs. However, the use of these drugs is associated with hepatotoxicity. Nuclear factor‑κB (NF‑κB) plays a crucial role in regulating immunity and inflammation. It has been reported that pyrrolidine dithiocarbamate (PDTC), an inhibitor of NF‑κB, exerts a hepatoprotective effect on acute and chronic liver damage. The aim of the present study was to explore the INH/RIF‑induced protective effects and mechanisms of PDTC on liver injury. Rats were intragastrically administered INH (50 mg/kg/day) and RIF (50 mg/kg/day) daily for 28 days. PDTC (50 mg/kg/day) was intraperitoneally injected 2 h after the co‑administration of INH and RIF to compare liver biochemical indicators in the serum, histopathological damage, NF‑κB activity, oxidative stress, hepatic mRNA expression of tumor necrosis factor (TNF)‑α, bile salt export pump (BSEP), and protein expression of BSEP. It was found that the inhibition of NF‑κB activation by PDTC treatment markedly alleviated liver biochemical and histological injury, decreased oxidative stress and mRNA levels of TNF‑α, and prevented decreases in BSEP mRNA and protein expression induced by the co‑administration of INH and RIF. Collectively, the present data suggested that INH/RIF‑induced liver injury is dependent on the activation of NF‑κB. PDTC exerted a therapeutic effect on INH/RIF‑induced liver injury by increasing BSEP expression, and exhibiting antioxidant and anti‑inflammatory activities.

Conformational turn triggers regio-selectivity in the bioactivation of thiophene-contained compounds mediated by cytochrome P450

In the present work, we performed Density Functional Theory calculations to explore the bioactivation mechanism of thiophene-containing molecules mediated by P450s. For this purpose, relatively large size compounds, 2,5-diaminothiophene derivatives were selected particularly for this investigation. Here we found the successive regio-selectivity triggered by conformational turn played a significant role in the occurrence of bioactivation. 2,5-Diaminothiophene was oxidized to a 2,5-diimine thiophene-reactive intermediate by Compound I (Cpd I) through successive activations of two N-H bonds (H3-N11 and H1-N6). This reaction exhibited three special characteristics: (1) self-controlled regio-selectivity during the oxidation process. There was a large scale of conformational turn in the abstraction of the first H atom which triggers the selection of the second H for abstraction. (2) Proton-shuttle mechanism. In high spin (HS) state, proton-shuttle mechanism was observed for the abstraction of the second H atom. (3) Spin-selective manner. In protein environment, the energy barrier in HS state was much lower than that in low spin state. The novel proposed bioactivation mechanism of 2,5-diaminothiophene compounds can help us in rational design of thiophene-contained drugs avoiding the occurrence of bioactivation.

Prophylactic Therapy of Silymarin (Milk Thistle) on Antituberculosis Drug-Induced Liver Injury: A Meta-Analysis of Randomized Controlled Trials

BACKGROUND

Prophylactic therapy with silymarin to prevent the development of antituberculosis drug-induced liver injury (anti-TB DILI) has been under debate. We aimed to evaluate the effect of silymarin in the prevention of anti-TB DILI.

METHODS

We searched MEDLINE, PubMed, Embase, and Cochrane Central Register of Controlled Trials (CENTRAL) up to 30th November 2018. Randomized controlled trials (RCTs) that compared silymarin and placebo to prevent anti-TB DILI were included. All statistical analyses were conducted using STATA 12.0 software. Standardized mean difference (SMD) and risk ratio (RR) with 95% confidence intervals (CIs) were used to evaluate the effect of silymarin. The quality of included studies was assessed according to Cochrane handbook. Funnel plots and Egger's tests were carried out to evaluate publication bias. Sensitivity analysis was conducted to assess the influence of each study.

RESULTS

A total of 1198 patients from five RCTs (585 with silymarin and 613 with placebo groups) were included. Overall, silymarin significantly reduced the occurrence of anti-TB DILI at week 4 [RR: 0.33, 95% CI (0.15, 0.75)]. In addition, silymarin exerted protective effect on liver function in patients undergoing anti-TB drugs [SMD = - 0.15, 95% CI (-0.24, -0.07), P < 0.001 (ALT); SMD =-0.14, 95% CI (-0.23, -0.06), P = 0.001(AST); SMD =-0.12, 95% CI (-0.20, -0.03), P = 0.008 (ALP)]. Silymarin led to similar AEs in placebo groups [OR: 1.09, 95% CI (0.86, 1.39), P = 0.47].

CONCLUSION

Prophylactic therapy of silymarin is contributed to a noticeably reduced risk of development of anti-TB DILI four weeks after the initiation. In addition, silymarin significantly improved the liver function in patients who are receiving anti-TB drugs.

Prominence of Oxidative Stress in the Management of Anti-tuberculosis Drugs Related Hepatotoxicity

Advanced medical services and treatments are available for treating Tuberculosis. Related prevalence has increased in recent times. Unfortunately, the continuous consumption of related drugs is also known for inducing hepatotoxicity which is a critical condition and cannot be overlooked. The present review article has focused on the pathways causing these toxicities and also the role of enzyme CYP2E1, hepatic glutathione, Nrf2-ARE signaling pathway, and Membrane Permeability Transition as possible targets which may help in preventing the hepatotoxicity induced by the drugs used in the treatment of tuberculosis.

Telfairia occidentalis (Cucurbitaceae) pulp extract mitigates rifampicin-isoniazid-induced hepatotoxicity in an in vivo rat model of oxidative stress

OBJECTIVE

Drug-induced liver injury complicates antituberculosis drug treatment and is a leading cause of death worldwide. The aim of this study is to establish the ethnomedicinal claim of hepatoprotective effects of fruit pulp extract of Telfairia occidentalis against rifampicin (RIF) and isoniazid (INH)-induced oxidative stress in rats.

METHODS

T. occidentalis pulp extract (TOPE) (125-500 mg/kg) and silymarin (50 mg/kg) were evaluated in an induced hepatotoxicity model of oxidative stress in Wistar rats by intoxication with RIF and INH (100 mg/kg each) orally for 60 d. Markers indicating oxidative stress and hepatic damage such as alanine aminotransferase (ALT), aspartate aminotransferase (AST) and alkaline phosphatase (ALP) were assessed. Biomarkers of antioxidant status, including catalase, glutathione reductase, glutathione peroxidase and superoxide dismutase, and marker of lipid peroxidation, malondialdehyde (MDA), were assayed using standard procedures. The hematological profile, lipid profile, serum markers for kidney function and histopathological examination were also assessed.

RESULTS

Intoxication with RIF and INH markedly reduced the hematological indices and elevated the biochemical enzyme markers (AST, ALT and ALP, P < 0.001) and lipid profile (P < 0.001), while antioxidant biomarkers were significantly (P < 0.01) depressed and MDA was elevated. However, pretreatment with TOPE significantly (P < 0.001) alleviated this alteration and sustained the antioxidant potentials. The histopathological morphology supports the biochemical evidence of hepatoprotection.

CONCLUSION

Current study is indicative of potential antioxidant activity, hepatoprotective effects and plausible therapeutic alleviation of RIF-INH-induced hepatotoxicity of TOPE in laboratory animals.

Hepatoprotective effect of lawsone on rifampicin-isoniazid induced hepatotoxicity in in vitro and in vivo models

The Drug-induced liver injury is one of the common unfavourable impacts, which seriously affects any drug therapy. This study documented the hepatoprotective efficacy of lawsone, the major bioactive naphthoquinone present in Lawsonia inermis L. (Lythraceae) using in vitro and in vivo models. Lawsone was isolated from the leaves of L. inermis and its structure was confirmed using spectroscopic data. In-vitro antioxidant effect of lawsone was evaluated using ABTS assay. Hepatoprotective effect of lawsone was determined with RIF-INH treated HepG2 cells and Wistar rats. Administration of RIF-INH reduced the viability of the HepG2 cells and the treatment with lawsone significantly restored the viability of the cells even at lower concentration (7.5 μM). The other parameters such as the leakage of transaminases and MDA levels were also significantly reduced by the treatment with lawsone. Oral administration of lawsone to the animals did not show any toxicity up to 2 g/kg b.w. concentration. Treatment with lawsone to the RIF-INH administered animals significantly lowered the serum transaminases levels. The ratio of albumin to globulin was improved and the level of bilirubin was lowered. This study indicated the hepatoprotective effect of lawsone; detailed investigations will give deeper understanding of the application of lawsone for hepatoprotection.

Hot aqueous leaf extract of Lasianthera africana (Icacinaceae) attenuates rifampicin-isoniazid-induced hepatotoxicity

OBJECTIVES

The aim of this study is to evaluate the hepatoprotective effect of Lasianthera africana (Icacinaceae) against isoniazid (INH) and rifampicin (RIF)-induced liver damage in rats.

METHODS

The hepatoprotective effects of hot aqueous L. africana (HALA) leaf extract (0.1-1 g/kg) and silymarin (50 mg/kg) were assessed in a model of oxidative liver damage induced by RIF and INH (100 mg/kg each) in Wistar rats for 28 days. Biochemical markers of hepatic damage such as alanine aminotransferase (ALT), aspartate aminotransferase (AST) and alkaline phosphatase (ALP) were assessed. The antioxidant statuses of plasma glutathione peroxidase (GSPx), glutathione reductase (GSH), catalase (CAT) and superoxide dismutase (SOD) and lipid peroxidation were evaluated.

RESULTS

The pretreatment of INH and RIF decreased hematological indices and the antioxidant levels (P < 0.001) and increased the levels of liver marker enzymes (P < 0.001). However, pretreatment with HALA extract and silymarin provoked significant elevation of hematological indices. The levels of AST, ALT, and ALP were depressed (P < 0.001). Total triglycerides, total cholesterol, total bilirubin and low-density lipoprotein were decreased (P < 0.001). However, high-density lipoprotein, bicarbonate, and electrolytes like chloride and potassium were elevated (P < 0.001), but sodium was depressed (P < 0.05). Additionally, GSH, GSPx, SOD and CAT were elevated (P < 0.01) and malondialdehyde was depressed (P < 0.001) when compared to the RIF-INH-treated rats. Histopathological evaluations support hepatoprotective activity.

CONCLUSION

This study demonstrated that HALA leaf extract attenuated RIF-INH-induced hepatotoxicity. L. africana could be exploited in management of RIF-INH-induced hepatitis.