Research progress of metformin in the treatment of liver fibrosis

The potential of flavonoids in hepatic fibrosis: A comprehensive review

BACKGROUND

Hepatic fibrosis is a pathophysiological process of extracellular matrix abnormal deposition induced by multiple pathogenic factors. Currently, there is still a lack of effective and non-toxic drugs for treating fibrosis in clinic. Flavonoids are polyphenolic compounds synthesized in plants and modern pharmacological studies confirmed flavonoids exhibit potent hepatoprotective effect.

PURPOSE

Summarize literature to elaborate the mechanism of HF and evaluate the potential of flavonoids in HF, aiming to provide a new perspective for future research.

METHODS

The literatures about hepatic fibrosis and flavonoids are collected via a series of scientific search engines including Google Scholar, Elsevier, PubMed, CNKI, WanFang, SciFinder and Web of Science database. The key words are "flavonoids", "hepatic fibrosis", "pharmacokinetic", "toxicity", "pathogenesis" "traditional Chinese medicine" and "mechanism" as well as combination application.

RESULTS

Phytochemical and pharmacological studies revealed that about 86 natural flavonoids extracted from Chinese herbal medicines possess significantly anti-fibrosis effect and the mechanisms maybe through anti-inflammatory, antioxidant, inhibiting hepatic stellate cells activation and clearing activated hepatic stellate cells.

CONCLUSIONS

This review summarizes the flavonoids which are effective in HF and the mechanisms in vivo and in vitro. However, fewer studies are focused on the pharmacokinetics of flavonoids in HF model and most studies are limited to preclinical studies, therefore there is no reliable data from clinical trials for the development of new drugs. Further in-depth research related it can be conducted to improve the bioavailability of flavonoids and serve the development of new drugs.

Metformin lotion promotes scarless skin tissue formation through AMPK activation, TGF-β1 inhibition, and reduced myofibroblast numbers

Scar tissue formation following skin wound healing is a challenging public health problem. Skin regeneration and preventing the formation of scar tissue by currently available commercial products are largely ineffective. This study aimed to test the efficacy of a novel topical metformin lotion (ML) in inhibiting scar tissue formation during skin wound healing in rats and to determine the mechanisms of action involved. A 6% ML was prepared in our laboratory. A skin wound healing model in rats was used. The wounded rats were divided into two groups and treated daily for 10 days as follows: Group 1 received a daily application of 50 mg of control lotion, or 0% ML (totaling 100 mg of lotion per rat), and Group 2 received a daily application of 50 mg of 6% ML (totaling 100 mg of 6% ML per rat). Blood samples from the heart of each rat were analyzed for inflammatory markers, HMGB1 and IL-1β, using ELISA, and immunological and histological analyses were performed on skin tissue sections. ML decreased levels of inflammatory markers HMGB1 and IL-1β in the serum of rats and inhibited the release of HMGB1 from cell nuclei into the skin tissue matrix. Additionally, ML demonstrated anti-fibrotic properties by enhancing AMPK activity, decreasing the expression of TGF-β1, reducing the number of myofibroblasts, decreasing the production of collagen III, and increasing the expression of collagen I. ML promotes the regeneration of high-quality skin during wound healing by reducing scar tissue formation. This effect is mediated through the activation of AMPK, inhibition of TGF-β1, and a decrease in the number of myofibroblasts.

Diabetic Pneumopathy- A Novel Diabetes-associated Complication: Pathophysiology, the Underlying Mechanism and Combination Medication

BACKGROUND

The "diabetic lung" has been identified as a possible target organ in diabetes, with abnormalities in ventilation control, bronchomotor tone, lung volume, pulmonary diffusing capacity, and neuroadrenergic bronchial innervation.

OBJECTIVE

This review summarizes studies related to diabetic pneumopathy, pathophysiology and a number of pulmonary disorders including type 1 and type 2 diabetes.

METHODS

Electronic searches were conducted on databases such as Pub Med, Wiley Online Library (WOL), Scopus, Elsevier, ScienceDirect, and Google Scholar using standard keywords "diabetes," "diabetes Pneumopathy," "Pathophysiology," "Lung diseases," "lung infection" for review articles published between 1978 to 2023 very few previous review articles based their focus on diabetic pneumopathy and its pathophysiology.

RESULTS

Globally, the incidence of diabetes mellitus has been rising. It is a chronic, progressive metabolic disease. The "diabetic lung" may serve as a model of accelerated ageing since diabetics' rate of respiratory function deterioration is two to three-times higher than that of normal, non-smoking people.

CONCLUSION

Diabetes-induced pulmonary dysfunction has not gained the attention it deserves due to a lack of proven causality and changes in cellular properties. The mechanism underlying a particular lung illness can still only be partially activated by diabetes but there is evidence that hyperglycemia is linked to pulmonary fibrosis in diabetic people.

Mitigating Scar Tissue Formation in Tendon Injuries: Targeting HMGB1, AMPK Activation, and Myofibroblast Migration All at Once

Tendon injuries, while prevalent, present significant challenges regarding their structural and functional restoration. Utilizing alpha-smooth muscle actin (α-SMA)-Ai9-scleraxis (Scx)-green fluorescent protein (GFP) transgenic mice, which exhibit both Scx (a tendon cell marker) and α-SMA (a myofibroblast marker), we explored the effects of metformin (Met) on tendon healing, repair, and its mechanisms of action. Our findings revealed that intraperitoneal (IP) injections of Met, administered before or after injury, as well as both, effectively prevented the release of HMGB1 into the tendon matrix and reduced circulating levels of HMGB1. Additionally, Met treatment increased and activated AMPK and suppressed TGF-β1 levels within the healing tendon. Tendon healing was also improved by blocking the migration of α-SMA+ myofibroblasts, reducing the prevalence of disorganized collagen fibers and collagen type III. It also enhanced the presence of collagen type I. These outcomes highlight Met's anti-fibrotic properties in acutely injured tendons and suggest its potential for repurposing as a therapeutic agent to minimize scar tissue formation in tendon injuries, which could have profound implications in clinical practice.

The mechanisms and therapeutic potential of long noncoding RNA NEAT1 in fibrosis

Fibrosis is the excess deposition of extracellular matrix involved in the pathogenesis of chronic diseases and finally leads to the disruption of tissue architecture and failure of organ function. Long noncoding RNAs (lncRNAs) are a class of RNAs with lengths greater than 200 nucleotides and do not code proteins, which regulate gene expression at multiple levels. Nuclear-enriched abundant transcript 1 (NEAT1) is a long noncoding RNA that is widely expressed in mammalian cells and known as essential architectural scaffold for the formation of paraspeckles. Recently, the accumulating studies demonstrated that lncRNA NEAT1 was remarkable upregulated in the development of fibrosis in different organs, such as liver fibrosis, renal fibrosis, cardiac fibrosis, and lung fibrosis. More importantly, knockdown of NEAT1 remarkably alleviated fibrosis in vitro and in vivo. In this review, we summarized current studies of NEAT1 in fibrosis and hopefully aid in a better understanding of the mechanisms of fibrosis and the potential of NEAT1 as novel therapeutic target for fibrosis.

Progression of the PI3K/Akt signaling pathway in chronic obstructive pulmonary disease

Chronic Obstructive Pulmonary Disease (COPD) is a chronic respiratory disease characterized by a slow progression and caused by the inhalation of harmful particulate matter. Cigarette smoke and air pollutants are the primary contributing factors. Currently, the pathogenesis of COPD remains incompletely understood. The PI3K/Akt signaling pathway has recently emerged as a critical regulator of inflammation and oxidative stress response in COPD, playing a pivotal role in the disease's progression and treatment. This paper reviews the association between the PI3K/Akt pathway and COPD, examines effective PI3K/Akt inhibitors and novel anti-COPD agents, aiming to identify new therapeutic targets for clinical intervention in this disease.

Fibrosis Development Linked to Alterations in Glucose and Energy Metabolism and Prooxidant-Antioxidant Balance in Experimental Models of Liver Injury

The development of liver fibrosis is one of the most severe and life-threatening outcomes of chronic liver disease (CLD). For targeted therapy of CLD, it is highly needed to reveal molecular targets for normalizing metabolic processes impaired in damaged liver and associated with fibrosis. In this study, we investigated the morphological and biochemical changes in rat liver models of fibrosis induced by chronic administration of thioacetamide, carbon tetrachloride, bile duct ligation (BDL), and ischemia/reperfusion (I/R), with a specific focus on carbohydrate and energy metabolism. Changes in the levels of substrates and products, as well as enzyme activities of the major glucose metabolic pathways (glycolysis, glucuronidation, and pentose phosphate pathway) were examined in rat liver tissue after injury. We examined key markers of oxidative energy metabolism, such as the activity of the Krebs cycle enzymes, and assessed mitochondrial respiratory activity. In addition, pro- and anti-oxidative status was assessed in fibrotic liver tissue. We found that 6 weeks of exposure to thioacetamide, carbon tetrachloride, BDL or I/R resulted in a decrease in the activity of glycolytic enzymes, retardation of mitochondrial respiration, elevation of glucuronidation, and activation of pentose phosphate pathways, accompanied by a decrease in antioxidant activity and the onset of oxidative stress in rat liver. Resemblance and differences in the changes in the fibrosis models used are described, including energy metabolism alterations and antioxidant status in the used fibrosis models. The least pronounced changes in glucose metabolism and mitochondrial functions in the I/R and thioacetamide models were associated with the least advanced fibrosis. Ultimately, liver fibrosis significantly altered the metabolic profile in liver tissue and the flux of glucose metabolic pathways, which could be the basis for targeted therapy of liver fibrosis in CLD caused by toxic, cholestatic, or I/R liver injury.

Activation of AMPK signalling by Metformin: Implication an important molecular mechanism for protecting against mice silicosis via inhibited endothelial cell-to-mesenchymal transition by regulating oxidative stress and apoptosis

Inhalation of silica particles (SiO₂) causes oxidative stress-induced inflammation and cell apoptosis, ultimately resulting in irreversible pulmonary fibrosis, Unfortunately, effective treatment or preventative measures have yet to be fully established. Metformin (Met), a relatively safe and effective medication for treating diabetes, may hold promise as protective agent against early-stage pulmonary fibrosis in mice through the activation of autophagy and inhibition of endothelial cell to mesenchymal transition (EndoMT). Here, we investigated whether Met could reduce silicosis in mice by regulating inflammation, oxidative stress, and apoptosis, and to identify the underlying protective effect on endothelial cells. First, through pathological observation, we found that 21 consecutive days of Met (100 mg/kg) administration is optimal against silicosis. Next, using haematoxylin-eosin and Masson's trichrome staining and immunoblotting, we found that Met effectively blunted the inflammatory response and collagen deposition at 56 days after exposure to SiO₂. We also demonstrated that Met effectively activates AMPK signalling and markedly relieves oxidative stress, the mitochondrial apoptotic pathway and EndoMT induced by SiO₂ exposure both in vivo and in vitro. Overall, Met can alleviate SiO₂-induced pulmonary fibrosis by regulating oxidative stress and the mitochondrial apoptotic pathway. The current study provides a rationale for the clinical treatment of SiO₂-induced pulmonary fibrosis.