Protective Effect of Carvedilol on Paracetamol-induced Hepatotoxicity; Role of Modulation Inflammation and Lipid Peroxidation

Novel peripheral role of Nurr-1/GDNF/AKT trajectory in carvedilol and/or morin hydrate hepatoprotective effect in a model of hepatic ischemia/reperfusion

Although the central role of Nurr-1/GDNF has been reviewed amply, scarce data are available on their peripheral impact. Carvedilol and morin hydrate have previously conferred their hepatic anti-fibrotic action.

AIM

Thus, our aim was to unveil the potential hepatoprotective role of carvedilol (CR) and/or morin hydrate (MH) using a hepatic 70% partial warm ischemia/reperfusion (I/R) rat model.

MAIN METHOD

Rats were allocated into sham-operated, hepatic I/R, and I/R preceded by oral administration of CR (10 and 30 mg/kg; CR₁₀/CR₃₀), MH (30 mg/kg), or CR₁₀ + MH for one week.

KEY FINDINGS

On the molecular level, pretreatment with CR and/or MH increased the hepatic contents of Nurr-1, GDNF, and the protein expression of active/p-AKT. On the other hand, they inactivated GSK3β and NF-κB to increase the antioxidant enzymes (GPx, SOD, CAT). All regimens also enhanced the autophagy/lysosomal function and boosted the protein expression of beclin-1, LC3II, and TFEB. Moreover, their antiapoptotic effect was signified by increasing the anti-apoptotic molecule Bcl2 and inhibiting Bax, Bax/Bcl2 ratio, and caspase-3, effects that were confirmed by the TUNEL assay. These improvements were reflected on liver function, as they decreased serum aminotransferases and liver structural alterations induced by I/R. Despite its mild impact, CR₁₀ showed marked improvements when combined with MH; this synergistic interaction overrides the effect of either regimen alone.

SIGNIFICANCE

In conclusion, CR, MH, and especially the combination regimen, conferred hepatoprotection against I/R via activating the Nurr-1/GDNF/AKT trajectory to induce autophagy/lysosomal biogenesis, inhibit GSK3β/NF-кB hub and apoptosis, and amend redox balance.

Metabolic and mitochondrial treatments for severe paracetamol poisoning: a systematic review

BACKGROUND

Paracetamol (acetaminophen) remains a leading cause of poisoning in Europe, North America, and Australia. For over four decades, acetylcysteine has been the antidote of choice. However, despite the use of acetylcysteine, some patients who ingest very large doses of paracetamol or who reach hospital late in the course of their poisoning, develop acute liver failure. Some will develop metabolic acidosis indicating mitochondrial toxicity.

OBJECTIVE

We review the experimental and clinical data reported with the use of cimetidine, fomepizole, and calmangafodipir in the treatment of paracetamol toxicity to determine if these treatments alone or in combination with acetylcysteine might be of benefit.

METHODS

We searched Ovid Medline 1946-2020, Embase 1947-2020, Scopus 2004-2020, Cochrane Databases of Systematic Reviews (CDSR), Cochrane Central Register of Controlled Trials (CENTRAL), and clinicaltrials.gov 1997-2020 for records including the concepts of paracetamol poisoning and cimetidine, fomepizole, calmangafodipir, and acetylcysteine. We included basic science studies in animals and all available study types in humans. We reviewed the reference lists of included articles to search for references missed in the original search. We registered the protocol in PROSPERO.

RESULTS

We completed all search strategies on 20 August 2019, 27 January 2020, and 15 June 2020. These produced 6,826 citations. We identified and deleted 2,843 duplicate resulting in a total of 3,856 unique citations. After applying inclusion and exclusion criteria, 89 studies remained. The largest numbers of studies described the past use of cimetidine, and the more recent use of fomepizole.Cimetidine: There is good animal evidence that cimetidine blocks CYP 2E1 with the potential to inhibit the toxic metabolism of paracetamol. Early case reports were inconclusive regarding the benefit to humans in paracetamol poisoning. Two comparative trials found no benefit of cimetidine in paracetamol poisoning, but few patients had severe poisoning.Fomepizole: There is good animal evidence that fomepizole blocks CYP 2E1 with the potential to inhibit the toxic metabolism of paracetamol. There are no comparative trials of fomepizole for acute paracetamol poisoning. Case reports are inconclusive due to multiple other interventions including the use of acetylcysteine in all cases. The benefit of fomepizole as adjunct treatment has not been demonstrated.Calmangafodipir: Calmangafodipir, a drug mimicking superoxide dismutase, has emerged as a potential treatment for severe paracetamol toxicity because the formation of superoxide free radicals appears to explain part of the mitochondrial toxicity of extremely large paracetamol overdoses. Calmangafodipir has reached Phase I/II trial of safety in humans with acute paracetamol overdose. Planning for a Phase III study of efficacy is currently underway.

CONCLUSIONS

The vast majority of patients with acute paracetamol overdose enjoy excellent outcomes with acetylcysteine alone. Although cimetidine and fomepizole inhibit CYP 2E1 in animals, there is insufficient evidence to recommend their use either as a primary treatment or adjunct therapy in paracetamol poisoning. Calmangafodipir remains investigational.

Liposomal Resveratrol and/or Carvedilol Attenuate Doxorubicin-Induced Cardiotoxicity by Modulating Inflammation, Oxidative Stress and S100A1 in Rats

Doxorubicin (DOX) is a cytotoxic anthracycline antibiotic and one of the important chemotherapeutic agents for different types of cancers. DOX treatment is associated with adverse effects, particularly cardiac dysfunction. This study examined the cardioprotective effects of carvedilol (CAR) and/or resveratrol (RES) and liposomal RES (LIPO-RES) against DOX-induced cardiomyopathy, pointing to their modulatory effect on oxidative stress, inflammation, S100A1 and sarco/endoplasmic reticulum calcium ATPase2a (SERCA2a). Rats received CAR (30 mg/kg) and/or RES (20 mg/kg) or LIPO-RES (20 mg/kg) for 6 weeks and were challenged with DOX (2 mg/kg) twice per week from week 2 to week 6. DOX-administered rats exhibited a significant increase in serum creatine kinase-MB (CK-MB), troponin-I and lactate dehydrogenase (LDH) along with histological alterations, reflecting cardiac cell injury. Cardiac toll-like receptor 4 (TLR-4), inducible nitric oxide synthase (iNOS), tumor necrosis factor (TNF)-α and interleukin (IL)-6 protein expression were up-regulated, and lipid peroxidation was increased in DOX-administered rats. Treatment with CAR, RES or LIPO-RES as well as their alternative combinations ameliorated all observed biochemical and histological alterations with the most potent effect exerted by CAR/LIPO-RES. All treatments increased cardiac antioxidants, and the expression of S100A1 and SERCA2a. In conclusion, the present study conferred new evidence on the protective effects of CAR and its combination with either RES or LIPO-RES on DOX-induced inflammation, oxidative stress and calcium dysregulation.