α‑lipoic acid protects against carbon tetrachloride‑induced liver cirrhosis through the suppression of the TGF‑β/Smad3 pathway and autophagy

Alpha-lipoic Acid: An Antioxidant with Anti-aging Properties for Disease Therapy

The anti-aging effects of alpha-lipoic acid (αLA), a natural antioxidant synthesized in human tissues, have attracted a growing interest in recent years. αLA is a short- -chain sulfur-containing fatty acid occurring in the mitochondria of all kinds of eukaryotic cells. Both the oxidized disulfide of αLA and its reduced form (dihydrolipoic acid, DHLA) exhibit prominent antioxidant function. The amount of αLA inside the human body gradually decreases with age resulting in various health disorders. Its lack can be compensated by supplying from external sources such as dietary supplements or medicinal dosage forms. The primary objectives of this study were the analysis of updated information on the latest two-decade research regarding the use of αLA from an anti-aging perspective. The information was collected from PubMed, Wiley Online Library, Scopus, ScienceDirect, SpringerLink, Google Scholar, and clinicaltrials.gov. Numerous in silico, in vitro, in vivo, and clinical studies revealed that αLA shows a protective role in biological systems by direct or indirect reactive oxygen/nitrogen species quenching. αLA demonstrated beneficial properties in the prevention and treatment of many age-related disorders such as neurodegeneration, metabolic disorders, different cancers, nephropathy, infertility, and skin senescence. Its preventive effects in case of Alzheimer's and Parkinson's diseases are of particular interest. Further mechanistic and clinical studies are highly recommended to evaluate the wide spectrum of αLA therapeutic potential that could optimize its dietary intake for prevention and alleviation disorders related to aging.

Chinese herbal decoction, Yi-Qi-Jian-Pi formula exerts anti-hepatic fibrosis effects in mouse models of CCl4-induced liver fibrosis

Background

Yi-Qi-Jian-Pi Formula (YQJPF) is a herbal medicine that is used to treat patients with liver failure. However, scientific evidence supporting the treatment of hepatic fibrosis with YQJPF has not been forthcoming. The present study aimed to determine the mechanisms underlying the anti-fibrotic effects of YQJPF in mouse models of hepatic fibrosis.

Methods

Mice were randomly assigned to control, hepatic fibrosis model, silymarin (positive treated), and low-, medium- and high-dose YQJPF (7.5, 15, and 30 g/kg, respectively) groups. Liver function, inflammatory cytokines, and oxygen stress were analyzed using ELISA kits. Sections were histopathologically stained with hematoxylin-eosin, Masson trichrome, and Sirius red. Macrophage polarization was measured by flow cytometry and immunofluorescence. Potential targets of YQJPF against hepatic fibrosis were analyzed by network pharmacology of Chinese herbal compound and the effects of YQJPF on the transforming growth factor-beta (TGF-β)/Suppressor of Mothers against Decapentaplegic family member 3 (Smad3) signaling pathway were assessed using qRT-PCR and immunohistochemical staining. Finally, metagenomics and LC-MS/MS were used to detect the intestinal flora and metabolites of the mice, and an in-depth correlation analysis was performed by spearman correlation analysis. The data were compared by one-way ANOVA and least significant differences (LSDs) or ANOVA-Dunnett's T3 method used when no homogeneity was detected.

Results

We induced hepatic fibrosis using CCl4 to establish mouse models and found that YQJPF dose-dependently increased body weight, improved liver function, and reversed hepatic fibrosis. Elevated levels of the pro-inflammatory factors IL-1β, IL-6, and TNF-α in the model mice were substantially decreased by YQJPF, particularly at the highest dose. Levels of serum malondialdehyde and superoxide dismutase (SOD) activity were elevated and reduced, respectively. The malondialdehyde concentration decreased and SOD activity increased in the high-dose group. M1 polarized macrophages (CD86) in the mouse models were significantly decreased and M2 polarization was mildly decreased without significance. However, high-dose YQJPF increased the numbers of M2 macrophages and inhibited TGF-β/Smad3 signaling. Metagenomic and non-targeted metabolomics detection results showed that YQJPF could regulate intestinal homeostasis, and Spearman correlation analysis showed that the abundance of Calditerrivibrio_nitroreducens was significantly negatively correlated with 18β-glycyrrhetinic acid. It is suggested that Calditerrivibrio_nitroreducens may reduce the anti-fibrosis effect of licorice and other Chinese herbs by digesting 18β-glycyrrhetinic acid.

Conclusions

YQJPF can reverse liver fibrosis by inhibiting inflammation, suppressing oxidative stress, regulating the immunological response initiated by macrophages, inhibiting TGF-β/Smad3 signaling and regulating intestinal flora homeostasis. Therefore, YQJPF may be included in clinical regimens to treat hepatic fibrosis.

Combined hepatoprotective pharmacotherapy for liver disease

Fixed-dose drug products as well as non-fixed hepatoprotective drug combinations are commonly used in modern clinical practice. Combined and concurrent drug use makes it possible to augment the pharmacological effects of individual agents, or extend the range of their potential indications. The drugs most commonly considered for combination therapy include essential phospholipids, glycyrrhizinic acid, ursodeoxycholic acid, silibinin, and S-adenosylmethionine. This paper discusses the rationale for combined use of liver-targeting drugs from a pathogenetic viewpoint, and provides a review of the evidence from clinical trials on combined pharmacotherapy for liver disease.

α-Lipoic Acid Protects against Cyclosporine A-Induced Hepatic Toxicity in Rats: Effect on Oxidative Stress, Inflammation, and Apoptosis

The clinical application of cyclosporine A (CsA) as an immunosuppressive agent is limited by its organ toxicity. We aimed to evaluate the effectiveness of α-lipoic acid against CsA-induced hepatotoxicity and to delineate the underlying molecular mechanisms. Male Wistar rats (n = 24, 8 per each group) received the vehicle, CsA (25 mg/kg) and/or ALA (100 mg/kg, p.o.) for 3 weeks. Biochemical markers of liver function (serum ALT, AST, ALP < GGT), oxidative stress (MDA, TAC, SOD, GSH, Nrf2/HO-1), inflammation (NF-κB, CD68, iNOS, NO, COX-2), and apoptosis (caspase-3) were assessed in serum and tissue. Liver histological analysis using H&E and Sirius red was performed. The development of liver injury in CsA-treated animals was indicated by elevated levels of liver enzymes, oxidants/antioxidants imbalance, inflammatory cells infiltration, up-regulated expression of inflammatory mediators, and apoptosis. These changes were associated with altered architecture of hepatic cells and fibrous connective tissue. ALA co-administration protected against CsA-induced liver damage and ameliorated biochemical changes and cellular injury. In conclusion, ALA demonstrated hepatoprotective potential against CsA-induced liver injury through combating oxidative stress, inflammation, and apoptosis, highlighting ALA as a valuable adjunct to CsA therapy.

Natural Sulfur-Containing Compounds: An Alternative Therapeutic Strategy against Liver Fibrosis

Liver fibrosis is a pathophysiologic process involving the accumulation of extracellular matrix proteins as collagen deposition. Advanced liver fibrosis can evolve in cirrhosis, portal hypertension and often requires liver transplantation. At the cellular level, hepatic fibrosis involves the activation of hepatic stellate cells and their transdifferentiation into myofibroblasts. Numerous pro-fibrogenic mediators including the transforming growth factor-β1, the platelet-derived growth factor, endothelin-1, toll-like receptor 4, and reactive oxygen species are key players in this process. Knowledge of the cellular and molecular mechanisms underlying hepatic fibrosis development need to be extended to find novel therapeutic strategies. Antifibrotic therapies aim to inhibit the accumulation of fibrogenic cells and/or prevent the deposition of extracellular matrix proteins. Natural products from terrestrial and marine sources, including sulfur-containing compounds, exhibit promising activities for the treatment of fibrotic pathology. Although many therapeutic interventions are effective in experimental models of liver fibrosis, their efficacy and safety in humans are largely unknown. This review aims to provide a reference collection on experimentally tested natural anti-fibrotic compounds, with particular attention on sulfur-containing molecules. Their chemical structure, sources, mode of action, molecular targets, and pharmacological activity in the treatment of liver disease will be discussed.