Inhibition of liver fibrosis by solubilized coenzyme Q10: Role of Nrf2 activation in inhibiting transforming growth factor-beta1 expression

Effects of idebenone and coenzyme Q10 on NLRP3/caspase-1/IL-1β pathway regulation on ethanol-induced hepatotoxicity in rats

Chronic and excessive alcohol consumption leads to liver toxicity. There is a need to investigate effective therapeutic strategies to alleviate alcohol-induced liver injury, which remains the leading cause of liver-related morbidity and mortality worldwide. Therefore here, we looked into and evaluated how ethanol-induced hepatotoxicity was affected by coenzyme Q10 (CoQ10) and its analog, idebenone (IDE), on the NLRP3/caspase-1/IL-1 pathway. Hepatotoxicity induced in rats through the oral administration of gradually increasing dosages of ethanol (from 2 to 6 g/kg/day) over 30 days and the effect of CoQ10 (10 or 20 mg/kg) and IDE (50 or 100 mg/kg) were evaluated. Serum hepatotoxicity markers (ALT, AST, GGT, ALP, and TBIL), tissue oxidative stress markers and the mRNA expressions of IL-1β, IL-18, TGF-β, NF-κB, NLRP3, and caspase-1 were evaluated. Masson's trichrome staining was also used to visualize fibrosis in the liver tissue. The results indicated that ethanol exposure led to hepatotoxicity as well as considerable NLRP3/caspase-1/IL-1β pathway activation. Moreover, CoQ10 or IDE treatment reduced measured parameters in a dosage-dependent manner. Thus, by inhibiting the NLRP3/caspase-1/IL-1 pathway, CoQ10 and IDE can prevent the hepatotoxicity caused by ethanol, although CoQ10 is more effective than IDE. This study will provide insight into new therapeutic avenues that take advantage of the anti-inflammatory and antioxidant properties of CoQ10 and IDE in ethanol-induced liver diseases.

Coenzyme Q-10 reduced the aberrant production of extracellular matrix proteins in uterine leiomyomas through transforming growth factor beta 3

OBJECTIVE

To evaluate the impact of coenzyme Q-10 (CoQ-10) on the dysregulated synthesis of extracellular matrix proteins mediated by transforming growth factor beta 3 (TGF-β3) in uterine leiomyomas.

DESIGN

Laboratory study.

SETTING

University.

PATIENTS

None.

INTERVENTIONS

Treatment of immortalized uterine myometrial and leiomyoma cells to TGF-β3 and CoQ-10.

MAIN OUTCOME MEASURES

The protein concentrations of collagen 1A1 (COL1A1), collagen 3A1 (COL3A1), collagen 11A1 (COL11A1), and fibronectin (FN1) were assessed through western blot analysis after treatment of immortalized uterine myometrial and leiomyoma cells with both transforming growth factor beta (TGF-β) 3 and concentrations of CoQ-10 at 10, 50, and 100 μM concurrently for 24 hours.

RESULTS

Immortalized uterine leiomyoma and myometrial cells exposed to TGF-β3 for 24 hours demonstrated a significant up-regulation of COL1A1, COL3A1, COL11A1, and FN1 compared with untreated cells. In leiomyoma cells, concurrent treatment with CoQ-10 over the same timeframe revealed a dose-dependent decrease in these protein concentrations compared with those in cells treated with TGF-β3 alone. At the highest concentration of 100 μM of CoQ-10, significant decreases in the amounts of COL1A1 (0.59 ± 0.10-fold), COL3A1 (0.46 ± 0.09-fold), COL11A1 (0.53 ± 0.09-fold), and FN1 (0.56 ± 0.09-fold) were observed. Similarly, myometrial cells exposed to both TGF-β3 and CoQ-10 demonstrated a dose-responsive decline in the amount of extracellular matrix protein compared with cells exposed to TGF-β3 alone. Significant reductions in the amounts of COL1A1 (0.75 ± 0.03-fold), COL3A1 (0.48 ± 0.06-fold), COL11A1 (0.38 ± 0.06), and FN1 (0.69 ± 0.04-fold) were appreciated at 100-μM CoQ-10.

CONCLUSION

Coenzyme Q-10 mitigated the aberrant production of key biomarkers of the extracellular matrix mediated by TGF-β3 in uterine leiomyomas. Our findings highlight a promising nonhormonal compound that can counteract the fibroproliferative process inherent to leiomyomas.

Evaluation of Antioxidant Effects of Coenzyme Q10 against Hyperglycemia-Mediated Oxidative Stress by Focusing on Nrf2/Keap1/HO-1 Signaling Pathway in the Liver of Diabetic Rats

Background

Hyperglycemia-induced oxidative stress can damage the liver and lead to diabetes complications. Coenzyme Q10 (CoQ-10) reduces diabetes-related oxidative stress. However, its molecular mechanisms are still unclear. This study aimed to examine CoQ-10's antioxidant capabilities against hyperglycemia-induced oxidative stress in the livers of diabetic rats, specifically targeting the Nrf2/Keap1/ARE signaling pathway.

Methods

This study was conducted between 2020-2021 at Arak University of Medical Sciences. A total of 30 male adult Wistar rats (8 weeks old) weighing 220-250 g were randomly assigned to five groups (n=6 in each group): control healthy, sesame oil (CoQ-10 solvent), CoQ-10 (10 mg/Kg), diabetic, and diabetic+CoQ-10. Liver oxidative stress indicators, including malondialdehyde, catalase, glutathione peroxidase, and glutathione, were estimated using the spectrophotometry method. Nrf2, Keap1, HO-1, and NQO1 gene expressions were measured using real-time PCR tests in the liver tissue. All treatments were conducted for 6 weeks. Statistical analysis was performed using SPSS software. One-way ANOVA followed by LSD's or Tukey's post hoc tests were used to compare the results of different groups. P<0.05 was considered statistically significant.

Results

The findings showed that induction of diabetes significantly increased Keap1 expression (2.1±0.9 folds, P=0.01), and significantly inhibited the mRNA expression of Nrf2 (0.38±0.2 folds, P=0.009), HO-1 (0.27±0.1 folds, P=0.02), and NQO1 (0.26±0.1 folds P=0.01), compared with the healthy group. In the diabetic group, the activity of glutathione peroxidase, catalase enzymes, and glutathione levels was decreased with an increase in malondialdehyde level. CoQ-10 supplementation significantly up-regulated the expressions of Nrf2 (0.85±0.3, P=0.04), HO-1 (0.94±0.2, P=0.04), NQO1 (0.88±0.5, P=0.03) genes, and inhibited Keap1 expression (1.1±0.6, P=0.02). Furthermore, as compared to control diabetic rats, CoQ-10 ameliorated oxidative stress by decreasing malondialdehyde levels and increasing catalase, glutathione peroxidase activities, and glutathione levels in the liver tissues of the treated rats in the treatment group.

Conclusion

The findings of this study revealed that CoQ-10 could increase the antioxidant capacity of the liver tissue in diabetic rats by modulating the Nrf2/Keap1/HO-1/NQO1 signaling pathway.

Analysis of evidence on nutraceutical interventions for Peyronie's disease: a guideline-based critical review

INTRODUCTION

The management of Peyronie's disease (PD) is a challenge for the clinician. Despite the lack of etiologic therapy, different nonsurgical approaches have often been empirically proposed. The most used treatment is based on nutraceutical drugs with antioxidant activity, although such an intervention remains controversial.

OBJECTIVES

We reviewed the evidence from the randomized controlled trials included in the recommendations of the American Urological Association (AUA), Canadian Urological Association (CUA), European Association of Urology, and International Society for Sexual Medicine.

METHODS

We searched PubMed, Scopus, Web of Science, and Cochrane Library for randomized controlled trials, reviews, and guidelines on nutraceutical interventions for PD.

RESULTS

Our analysis provides detailed information on potential interventions, underlying the inconsistent evidence. Acetyl esters of carnitine, although not recommended by any of the available guidelines, showed potential benefit in some selected studies. Omega-3 fatty acids are not recommended due to withdrawn study evidence. The CUA and AUA were the only societies to consider the use of coenzyme Q10. While the CUA suggested that it might be offered as a treatment option, the AUA refrained from taking a definitive stance due to insufficient evidence. Similarly, conflicting recommendations have been produced on potassium para-aminobenzoate. While the CUA considers potassium para-aminobenzoate potentially useful in slowing PD progression, the AUA deems the evidence insufficient. Conversely, both the International Society for Sexual Medicine and European Association of Urology do not recommend its use.

CONCLUSION

This critical comparative analysis of the most recent guidelines produced by the leading scientific societies highlights some inconsistencies in the recommendations on nutraceutical intervention for PD, even within a background of overall ineffectiveness of this treatment approach.

Evidence for TGF-β1/Nrf2 Signaling Crosstalk in a Cuprizone Model of Multiple Sclerosis

Multiple sclerosis (MS) is a chronic and degenerative disease that impacts central nervous system (CNS) function. One of the major characteristics of the disease is the presence of regions lacking myelin and an oxidative and inflammatory environment. TGF-β1 and Nrf2 proteins play a fundamental role in different oxidative/inflammatory processes linked to neurodegenerative diseases such as MS. The evidence from different experimental settings has demonstrated a TGF-β1-Nrf2 signaling crosstalk under pathological conditions. However, this possibility has not been explored in experimental models of MS. Here, by using the cuprizone-induced demyelination model of MS, we report that the in vivo pharmacological blockage of the TGF-β1 receptor reduced Nrf2, catalase, and TGFβ-1 protein levels in the demyelination phase of cuprizone administration. In addition, ATP production, locomotor function and cognitive performance were diminished by the treatment. Altogether, our results provide evidence for a crosstalk between TGF-β1 and Nrf2 signaling pathways under CNS demyelination, highlighting the importance of the antioxidant cellular response of neurodegenerative diseases such as MS.

Fabrication of a decellularized liver matrix-based hepatic patch for the repair of CCl4-induced liver injury

This article primarily introduces a new treatment for liver fibrosis/cirrhosis. We developed a hepatic patch by combining decellularized liver matrix (DLM) with the hepatocyte growth factor (HGF)/heparin-complex and evaluated its restorative efficacy. In vitro prophylactic results, the HGF/heparin-DLM patches effectively mitigated CCl4-induced hepatocyte toxicity and restored the cytotoxicity levels to the baseline levels by day 5. Furthermore, these patches restored albumin synthesis of injured hepatocytes to more than 70% of the normal levels within 5 days. In vitro therapeutic results, the urea synthesis of the injured hepatocytes reached 91% of the normal levels after 10 days of culture, indicating successful restoration of hepatic function by the HGF/heparin-DLM patches in both prophylactic and therapeutic models. In vivo results, HGF/heparin-DLM patches attached to the liver and gut exhibited a significant decrease in collagen content (4.44 times and 2.77 times, respectively) and an increase in glycogen content (1.19 times and 1.12 times, respectively) compared to the fibrosis group after 1 week, separately. In summary, liver function was restored and inflammation was inhibited through the combined effects of DLM and the HGF/heparin-complex in fibrotic liver. The newly designed hepatic patch holds promise for both in vitro and in vivo regeneration therapy and preventive health care for liver tissue engineering.

Involvement of Nrf2-PPAR-γ signaling in Coenzyme Q10 protecting effect against methotrexate-induced testicular oxidative damage

Studies have identified Coenzyme Q10 (CoQ10) as a promising agent in improving idiopathic male infertility; however, its role in chemically or environmentally induced testicular dysfunction is not well-established. We investigated the potential of CoQ10 to attenuate methotrexate (MTX)-induced testicular damage and to identify molecular targets of CoQ10 effects. Wistar rats received a single intraperitoneal dose of 20 mg/kg MTX on the fifth day of the 10-day experimental protocol. 100 mg/kg CoQ10 was given orally daily for ten days, alone or combined with MTX. The testes of MTX-treated animals showed thickened tunica albuginea, distortion of seminiferous tubules with a marked reduction of germinal lining, a few primary spermatocytes with no spermatozoa, apoptotic cells, congested sub-capsular and interstitial blood vessels, and interstitial edema. Reduction of reproductive hormones and increased oxidative, inflammatory, and apoptotic biomarkers levels were also seen in the MTX-treated rats. CoQ10 + MTX-treated rats were protected against MTX-induced testicular histological changes and showed improvement in testosterone, luteinizing-, and follicle-stimulating hormone serum levels compared to the MTX group. The testes of the CoQ10 + MTX-treated rats showed reduced malondialdehyde, myloperoxidase, tumor necrosis factor -α, interleukin-6 and -1β and Bax: Bcl2 ratio and enhanced glutathione, and catalase compared to MTX alone. CoQ10 enhanced MTX-induced downregulation of Nrf2 and PPAR-γ signaling and modulated its downstream targets, the inducible nitric oxide synthase, NF-κB, Bax, and Bcl2. In conclusion, CoQ10 targeted the Nrf2-PPAR-γ signaling loop and its downstream pathways, mitigating MTX-induced oxidative stress-related damages and alleviating the testicular dysfunction MTX caused. Our data suggest Nrf2-PPAR-γ signaling as a potential therapeutic target in testicular toxicity, where oxidative stress, inflammation, and apoptosis trigger damage.

Redox Biology and Liver Fibrosis

Hepatic fibrosis is a complex process that develops in chronic liver diseases. Even though the initiation and progression of fibrosis rely on the underlying etiology, mutual mechanisms can be recognized and targeted for therapeutic purposes. Irrespective of the primary cause of liver disease, persistent damage to parenchymal cells triggers the overproduction of reactive species, with the consequent disruption of redox balance. Reactive species are important mediators for the homeostasis of both hepatocytes and non-parenchymal liver cells. Indeed, other than acting as cytotoxic agents, reactive species are able to modulate specific signaling pathways that may be relevant to hepatic fibrogenesis. After a brief introduction to redox biology and the mechanisms of fibrogenesis, this review aims to summarize the current evidence of the involvement of redox-dependent pathways in liver fibrosis and focuses on possible therapeutic targets.

Aqueous Fraction from Cucumis sativus Aerial Parts Attenuates Angiotensin II-Induced Endothelial Dysfunction In Vivo by Activating Akt

BACKGROUND

Endothelial dysfunction (ED) is a marker of vascular damage and a precursor of cardiovascular diseases such as hypertension, which involve inflammation and organ damage. Nitric oxide (NO), produced by eNOS, which is induced by pAKT, plays a crucial role in the function of a healthy endothelium.

METHODS

A combination of subfractions SF1 and SF3 (C4) of the aqueous fraction from Cucumis sativus (Cs-Aq) was evaluated to control endothelial dysfunction in vivo and on HMEC-1 cells to assess the involvement of pAkt in vitro. C57BL/6J mice were injected daily with angiotensin II (Ang-II) for 10 weeks. Once hypertension was established, either Cs-AqC4 or losartan was orally administered along with Ang-II for a further 10 weeks. Blood pressure (BP) was measured at weeks 0, 5, 10, 15, and 20. In addition, serum creatinine, inflammatory status (in the kidney), tissue damage, and vascular remodeling (in the liver and aorta) were evaluated. Cs-AqC4 was also tested in vitro on HMEC-1 cells stimulated by Ang-II to assess the involvement of Akt phosphorylation.

RESULTS

Cs-AqC4 decreased systolic and diastolic BP, reversed vascular remodeling, decreased IL-1β and TGF-β, increased IL-10, and decreased kidney and liver damage. In HMEC-1 cells, AKT phosphorylation and NO production were increased.

CONCLUSIONS

Cs-AqC4 controlled inflammation and vascular remodeling, alleviating hypertension; it also improved tissue damage associated with ED, probably via Akt activation.

Novel Therapeutic Approaches to Liver Fibrosis Based on Targeting Oxidative Stress

Chronic liver disease (CLD) constitutes a growing global health issue, with no effective treatments currently available. Oxidative stress closely interacts with other cellular and molecular processes to trigger stress pathways in different hepatic cells and fuel the development of liver fibrosis. Therefore, inhibition of reactive oxygen species (ROS)-mediated effects and modulation of major antioxidant responses to counteract oxidative stress-induced damage have emerged as interesting targets to prevent or ameliorate liver injury. Although many preclinical studies have shown that dietary supplements with antioxidant properties can significantly prevent CLD progression in animal models, this strategy has not proved effective to significantly reduce fibrosis when translated into clinical trials. Novel and more specific therapeutic approaches are thus required to alleviate oxidative stress and reduce liver fibrosis. We have reviewed the relevant literature concerning the crucial role of alterations in redox homeostasis in different hepatic cell types during the progression of CLD and discussed current pharmacological approaches to ameliorate fibrosis by reducing oxidative stress focusing on selective modulation of enzymatic oxidant sources, antioxidant systems and ROS-mediated pathogenic processes.

Effects of coenzyme Q10 supplementation on lipid profiles and liver enzymes of nonalcoholic fatty liver disease (NAFLD) patients: A systematic review and meta-analysis of randomized controlled trials

As an antioxidant, coenzyme Q 10 (CoQ10) has been proposed as a possible treatment for non-alcoholic fatty liver disease (NAFLD). In the present meta-analysis, we aimed to determine the effects of CoQ10 supplementation on lipid profiles and liver enzymes of NAFLD patients. We searched PubMed, Web of Science, Scopus, and Cochrane Library on 21 April 2022 to retrieve randomized controlled trials on NAFLD patients in which CoQ10 was utilized as a treatment. Data were pooled using the random-effects model and weighted mean difference (WMD) was considered as the summary effect size. The analysis of the six included studies indicated an overall non-significant decrease in the lipid profiles (total cholesterol (TC), low-density lipoprotein cholesterol (LDL), high-density lipoprotein cholesterol (HDL), and triglyceride (TG)), and liver enzymes (aspartate transaminase (AST), alanine transaminase (ALT), and gamma-glutamyltransferase (GGT)) of NAFLD patients who received CoQ10. Sensitivity analysis using "leave-one out" method showed a significant reduction in AST, and GGT after excluding certain studies. Also, subgroup analyses showed significant difference based on CoQ10 dose for TC, AST, and GGT, and also a significant decrease in AST based on the duration of the intervention. No publication bias was found between the studies. Although an overall non-significant decrease was observed in lipid profiles and liver enzymes of NAFLD patients, the results of sensitivity and subgroup analyses showed significant effects of CoQ10 in certain conditions. Further RCTs should be done in light of our findings.

Apparent Opportunities and Hidden Pitfalls: The Conflicting Results of Restoring NRF2-Regulated Redox Metabolism in Friedreich's Ataxia Pre-Clinical Models and Clinical Trials

Friedreich's ataxia (FRDA) is an autosomal, recessive, inherited neurodegenerative disease caused by the loss of activity of the mitochondrial protein frataxin (FXN), which primarily affects dorsal root ganglia, cerebellum, and spinal cord neurons. The genetic defect consists of the trinucleotide GAA expansion in the first intron of FXN gene, which impedes its transcription. The resulting FXN deficiency perturbs iron homeostasis and metabolism, determining mitochondrial dysfunctions and leading to reduced ATP production, increased reactive oxygen species (ROS) formation, and lipid peroxidation. These alterations are exacerbated by the defective functionality of the nuclear factor erythroid 2-related factor 2 (NRF2), a transcription factor acting as a key mediator of the cellular redox signalling and antioxidant response. Because oxidative stress represents a major pathophysiological contributor to FRDA onset and progression, a great effort has been dedicated to the attempt to restore the NRF2 signalling axis. Despite this, the beneficial effects of antioxidant therapies in clinical trials only partly reflect the promising results obtained in preclinical studies conducted in cell cultures and animal models. For these reasons, in this critical review, we overview the outcomes obtained with the administration of various antioxidant compounds and critically analyse the aspects that may have contributed to the conflicting results of preclinical and clinical studies.

A micronutrient mixture with collagen peptides, probiotics, cannabidiol, and diet may reduce aging, and development and progression of age-related alzheimer's disease, and improve its treatment

Human aging involves gradual decline in organ functions leading to organ specific age-related chronic diseases such as Alzheimer's disease (AD). Although advances in the development of new drugs, novel surgical procedures, improved diet and lifestyle, have resulted in doubling of lifespan of humans, the quality of life in many cases remains poor because of increased incidence of age-related chronic diseases. Using experimental models of accelerated aging, several cellular defects associated with aging and AD have been identified. Some cellular defects due to increased oxidative stress, chronic inflammation, autophagy defects, mitochondrial dysfunction, and imbalances in the composition probiotics in favor of harmful bacteria over beneficial bacteria are common to both aging and AD, while others such as telomere attrition, loss of collagen, elastin, and hyaluronic acid, failure of DNA repair system, and impaired immune function are unique to aging; and some such as increased production of beta-amyloids, hyperphosphorylation of tau protein, and abnormal behaviors are unique to AD. It is suggested that supplementation with a micronutrient mixture, probiotics, collagen peptides, CBD, and modifications in the diet and lifestyle may reduce the aging processes, and the development, progression of AD, and improve the treatments of this disease.

Coenzyme Q10 ameliorates carbofuran induced hepatotoxicity and nephrotoxicity in wister rats

Carbofuran is a widely used poisonous pesticide around the world that helps to control insects during farming. Upon oral ingestion to humans, it exaggerates oxidative stress in various organs like the liver, brain, kidney, and heart. Several studies reported that oxidative stress in the liver initiates and propagates hepatic cell necrosis, ultimately resulting in hepatotoxicity. It also reported that coenzyme Q10 (CoQ10) can neutralize oxidative stress due to its antioxidant properties. However, the hepatoprotective and nephroprotective role of CoQ10 against carbofuran toxicity has not been investigated. Therefore, the present study aimed to evaluate the hepatoprotective and nephroprotective role of CoQ10 in carbofuran-induced hepatotoxicity and nephrotoxicity in a mouse model for the first time. We determined the blood serum diagnostic markers, oxidative stress parameters, antioxidant system, and histopathological characteristics of liver and kidney tissues. The administration of 100 mg/kg of CoQ10 in carbofuran-treated rats significantly attenuated AST, ALT, ALP, serum creatinine, and BUN levels. Moreover, CoQ10 (100 mg/kg) remarkably altered the level of NO, MDA, AOPP, GSH, SOD, and CAT in both the liver and kidney. The histopathological data also unveiled that CoQ10 treatment prevented inflammatory cell infiltration in carbofuran-exposed rats. Therefore, our findings infer that CoQ10 may effectively protect liver and kidney tissues against carbofuran-induced oxidative hepatotoxicity and nephrotoxicity.

Immune response gene 1 deficiency impairs Nrf2 activation and aggravates liver fibrosis in mice

A growing body of evidence suggests that metabolic events play essential roles in the development of liver fibrosis. Immune response gene 1 (IRG1) catalyzes the generation of itaconate, which function as a metabolic checkpoint under several pathological circumstances. In the present study, the hepatic level of IRG1 was determined in mice with carbon tetrachloride (CCl₄)-induced liver fibrosis. And then the pathological significance of IRG1 and the pharmacological potential of 4-octyl itaconate (4-OI), a cell-permeable derivate of itaconate, in liver fibrosis were investigated in mice. The results indicated that the hepatic level of IRG1 was upregulated in mice with liver fibrosis. CCl₄-induced formation of fibrotic septa and deposition of collagen was aggravated in IRG1 KO mice. IRG1 deletion also resulted in increased expression of transforming growth factor beta 1 (TGF-β1), enhanced phosphorylation of Smad3, elevated level of alpha smooth muscle actin (α-SMA) and hydroxyproline, which were associated with compromised activation of nuclear erythroid 2-related factor 2 (Nrf2)-mediated antioxidant system and exacerbated oxidative stress. Interestingly, supplementation with 4-OI activated Nrf2 pathway, suppressed TGF-β1 signaling and attenuated fibrogenesis. Our data indicated that upregulation of IRG1 might function as a protective response during the development of liver fibrosis, and 4-OI might have potential value for the pharmacological intervention of liver fibrosis.

Green Synthesis of Silymarin-Chitosan Nanoparticles as a New Nano Formulation with Enhanced Anti-Fibrotic Effects against Liver Fibrosis

Background: Silymarin (SIL) has long been utilized to treat a variety of liver illnesses, but due to its poor water solubility and low membrane permeability, it has a low oral bioavailability, limiting its therapeutic potential. Aim: Design and evaluate hepatic-targeted delivery of safe biocompatible formulated SIL-loaded chitosan nanoparticles (SCNPs) to enhance SIL’s anti-fibrotic effectiveness in rats with CCl₄-induced liver fibrosis. Methods: The SCNPs and chitosan nanoparticles (CNPs) were prepared by ionotropic gelation technique and are characterized by physicochemical parameters such as particle size, morphology, zeta potential, and in vitro release studies. The therapeutic efficacy of successfully formulated SCNPs and CNPs were subjected to in vivo evaluation studies. Rats were daily administered SIL, SCNPs, and CNPs orally for 30 days. Results: The in vivo study revealed that the synthesized SCNPs demonstrated a significant antifibrotic therapeutic action against CCl₄-induced hepatic injury in rats when compared to treated groups of SIL and CNPs. SCNP-treated rats had a healthy body weight, with normal values for liver weight and liver index, as well as significant improvements in liver functions, inflammatory indicators, antioxidant pathway activation, and lipid peroxidation reduction. The antifibrotic activities of SCNPs were mediated by suppressing the expression of the main fibrosis mediators TGFβR1, COL3A1, and TGFβR2 by boosting the hepatic expression of protective miRNAs; miR-22, miR-29c, and miR-219a, respectively. The anti-fibrotic effects of SCNPs were supported by histopathology and immunohistochemistry (IHC) study. Conclusions: According to the above results, SCNPs might be the best suitable carrier to target liver cells in the treatment of liver fibrosis.

Preparation and Characterization of Silymarin-Conjugated Gold Nanoparticles with Enhanced Anti-Fibrotic Therapeutic Effects against Hepatic Fibrosis in Rats: Role of MicroRNAs as Molecular Targets

BACKGROUND

The main obstacles of silymarin (SIL) application in liver diseases are its low bioavailability, elevated metabolism, rapid excretion in bile and urine, and inefficient intestinal resorption. The study aimed to synthesize and characterize silymarin-conjugated gold nanoparticles (SGNPs) formulation to improve SIL bioavailability and release for potentiating its antifibrotic action.

METHODS

Both SGNPs and gold nanoparticles (GNPs) were prepared and characterized using standard characterization techniques. The improved formulation was assessed for in vitro drug release study and in vivo study on rats using CCl₄ induced hepatic fibrosis model. SIL, SGNPs, and GNPs were administered by oral gavage daily for 30 days. At the end of the study, rats underwent anesthesia and were sacrificed, serum samples were collected for biochemical analysis. Liver tissues were collected to measure the genes and microRNAs (miRNAs) expressions. Also, histopathological and immunohistochemistry (IHC) examinations of hepatic tissues supported these results.

RESULTS

The successful formation and conjugation of SGNPs were confirmed by measurements methods. The synthesized nanohybrid SGNPs showed significant antifibrotic therapeutic action against CCl₄-induced hepatic damage in rats, and preserved normal body weight, liver weight, liver index values, retained normal hepatic functions, lowered inflammatory markers, declined lipid peroxidation, and activated the antioxidant pathway nuclear factor erythroid-2-related factor 2 (NRF2). The antifibrotic activities of SGNPs mediated through enhancing the hepatic expression of the protective miRNAs; miR-22, miR-29c, and miR-219a which results in suppressed expression of the main fibrosis mediators; TGFβR1, COL3A1, and TGFβR2, respectively. The histopathology and IHC analysis confirmed the anti-fibrotic effects of SGNPs.

CONCLUSIONS

The successful synthesis of SGNPs with sizes ranging from 16 up to 20 nm and entrapment efficiency and loading capacity 96% and 38.69%, respectively. In vivo studies revealed that the obtained nano-formulation of SIL boosted its anti-fibrotic effects.

Protective Potential of Ginseng and/or Coenzyme Q10 on Doxorubicin-induced Testicular and Hepatic Toxicity in Rats

Introduction: Although doxorubicin (DOX) is a successful cancer chemotherapeutic, side effects limit the clinical utility of DOX-based therapy, including male infertility and hepatotoxicity. Objective: To evaluate the testicular and hepatoprotective effect of ginseng and/or coenzyme Q10 (CoQ10) in rats exposed to DOX and the possible underlying mechanisms. Materials and Methods:  Fifty adult male albino rats were divided into (10/group), control, DOX group, DOX/Gin group, DOX/CoQ10 group and DOX/Gin+CoQ10 group. Serum testosterone, serum liver enzymes, fasting serum cholesterol and triglyceride (TG), tissue malondialdehyde (MDA), tissue superoxide dismutase (SOD), serum tumor necrosis factor-alpha (TNF-α), serum interleukin 6, serum interleukin 10, nuclear factor E2‐related factor 2 (Nrf2) gene expression in liver and testis and organ indices were measured.  Histopathological and immunohistochemical assessments of apoptotic marker kaspase3 in testis and liver were also performed. Results DOX-induced toxicity is associated with a significant decrease in serum testosterone, testis and liver index values, testicular and hepatic SOD,  testicular and hepatic Nrf2 gene expression and serum interleukin 10. However, there was a significant increase in serum liver enzymes, serum cholesterol and TG, testicular and hepatic MDA, serum TNF-α and serum interleukin 6 when compared with the control group. The combination of ginseng and CoQ10 resulted in significant improvement of DOX-induced changes when compared with other treated groups. Conclusion: Ginseng and CoQ10 have valuable therapeutic effects on DOX-induced testicular and hepatic toxicity via up-regulation of Nrf2 gene expression, inhibition of apoptosis, anti-oxidant, anti-inflammatory and hypolipidemic effects.

Can a Micronutrient Mixture Delay the Onset and Progression of Symptoms of Single-Point Mutation Diseases?

Single-point mutation diseases in which substitution of one nucleotide with another in a gene occurs include familial Alzheimer's disease (fAD), familial Parkinson's disease (fPD), and familial Creutzfeldt-Jacob disease (fCJD) as well as Huntington's disease (HD), sickle cell anemia, and hemophilia. Inevitability of occurrence of these diseases is certain. However, the time of appearance of symptoms could be influenced by the diet, environment, and possibly other genetic factors. There are no effective approaches to delay the onset or progression of symptoms of these diseases. The fact that increased oxidative stress and inflammation significantly contribute to the initiation and progression of these point mutation diseases shows that antioxidants could be useful. The major objectives are (a) to present evidence that increased oxidative stress and chronic inflammation are associated with selected single-point mutation diseases, such as fAD, fPD, and fCJD, HD, sickle cell anemia, and hemophilia; (b) to describe limited studies on the role of individual antioxidants in experimental models of some of these diseases; and (c) to discuss a rationale for utilizing a comprehensive mixture of micronutrients, which may delay the development and progression of symptoms of above diseases by simultaneously reducing oxidative and inflammatory damages.Key teaching pointsSelected single-point mutation diseases and their pattern of inheritanceCharacteristics of each selected single-point mutation diseaseEvidence for increased oxidative stress and inflammation in each diseasePotential reasons for failure of single antioxidants in human studiesRationale for using a comprehensive mixture of micronutrients in delaying the onset and progression of single-point mutation diseases.

Chlorogenic acid, quercetin, coenzyme Q10 and silymarin modulate Keap1-Nrf2/heme oxygenase-1 signaling in thioacetamide-induced acute liver toxicity

BACKGROUND AND AIMS

The normal functioning of Kelch-like ECH-associated protein-1 (Keap1)/nuclear factor erythroid 2-related factor 2 (Nrf2) complex is necessary for the cellular protection against oxidative stress. We investigated the effect of chlorogenic acid (CGA), quercetin (Qt), coenzyme Q10 (Q10) and silymarin on the expression of Keap1/Nrf2 complex and its downstream target; heme oxygenase-1 (HO-1) as well as inflammation and apoptosis in an acute liver toxicity model induced by thioacetamide (TAA).

MAIN METHODS

Wistar rats were divided into 13 groups: Control, silymarin, CGA, Qt, Q10, TAA (single dose 50 mg/kg, i.p.), TAA + silymarin (400 mg/kg, p.o.), TAA + CGA (100 & 200 mg/kg, p.o.), TAA + Qt (200 &300 mg/kg, p.o.) and TAA+ Q10 (30&50 mg/kg, p.o.) and treated for 8 days.

KEY FINDINGS

The results showed improved liver functions and hepatic tissue integrity in all tested doses of TAA + silymarin, TAA + CGA, TAA + Qt and TAA + Q10 groups compared to the TAA group. Furthermore, these groups showed significantly lower ROS, malondialdehyde and nitric oxide levels but higher glutathione content and superoxide dismutase activity compared to the TAA group, p < 0.05. In these groups, Keap1 expression was significantly decreased while Nrf2 expression and HO-1 activity were increased. In addition, the number of apoptotic cells and the expression level of TNF-α in the liver tissues were significantly decreased compared to the TAA group.

SIGNIFICANCE

CGA, Qt, Q10 and silymarin protect against TAA-induced acute liver toxicity via antioxidant, anti-inflammatory, anti-apoptotic activities and regulating Keap1-Nrf2/HO-1 expression.

A randomized controlled trial on the coloprotective effect of coenzyme Q10 on immune-inflammatory cytokines, oxidative status, antimicrobial peptides, and microRNA-146a expression in patients with mild-to-moderate ulcerative colitis

PURPOSE

Coenzyme Q10 (CoQ10), having potent antioxidant and anti-inflammatory pharmacological properties, has recently been shown to be a safe and promising agent in maintaining remission of ulcerative colitis (UC). This trial was, therefore, designed to determine CoQ10 efficacy on inflammation and antioxidant status, antimicrobial peptides, and microRNA-146a expression in UC patients.

METHODS

In this randomized double-blind controlled trial, 88 mild-to-moderate UC patients were randomly allocated to receive CoQ10 (200 mg/day) or placebo (rice flour) for 2 months. At the baseline and at an 8-week follow-up, serum levels of Nrf2, cathelicidin LL-37, β-defensin 2, IL-10, IL-17, NF-κB p65 activity in peripheral blood mononuclear cells (PBMCs), simple clinical colitis activity index questionnaire (SCCAIQ), and quality of life (IBDQ-32 score), as well as an expression rate of microRNA-146a were measured.

RESULTS

A significant reduction was detected in the serum IL-17 level, activity of NF-κB p65 in PBMCs, and also SCCAI score in the CoQ10 group compared to the placebo group, whereas IL-10 serum concentrations and IBDQ-32 score of the CoQ10 group considerably increased versus the control group; the changes of these variables were also significantly different within and between groups at the end of the study. Furthermore, CoQ10 remarkably increased serum levels of cathelicidin LL-37. A significant change in serum cathelicidin LL-37 levels was also observed between the two groups. No statistical difference, however, was seen between the two groups in terms of the serum levels of Nrf2 and β-defensin 2 and the relative expression of microRNA-146a.

CONCLUSIONS

Our results indicate that CoQ10 supplementation, along with drug therapy, appears to be an efficient reducer of inflammation in patients with mild-to-moderate UC at a remission phase.

TRIAL REGISTRATION

The research has also been registered at the Iranian Registry of Clinical Trials (IRCT): IRCT20090822002365N17.

Salvianolic acid B protects against acute and chronic liver injury by inhibiting Smad2C/L phosphorylation

Salvianolic acid B (Sal B) has strong antioxidant and anti-fibrosis effects, which are related to the transforming growth factor β/Smad signaling pathway. However, how Sal B affects this antioxidant pathway and the phosphorylation (p-) of Smad2 at both the COOH-terminal (pSmad2C) and linker region (pSmad2L) are unknown. The aims of the present study were to investigate the underlying mechanisms of Sal B on acute and chronic liver injury induced by CCl₄ and H₂O₂, and its effects on p-Smad2C/L. In in vivo experiments, acute and chronic liver injury models were induced by CCl₄, and the oxidative damage cell model was established in vitro with H₂O₂. Liver histopathology was assessed using hematoxylin and eosin and Van Gieson's staining. Moreover, serum biochemical indicators were analyzed using specific assay kits. Furthermore, the present study evaluated the oxidant/antioxidant status in acute and chronic liver injury models by oxidative stress parameters such as malondialdehyde, glutathione and superoxide dismutase. In addition, western blot analysis was performed to analyze the protein expression levels of pSmad2C, pSmad2L, nuclear factor erythroid-2-related factor 2 (Nrf2) and heme oxygenase-1 (HO-1). It was found that Sal B improved liver histology, decreased the levels of aminotransferase and attenuated oxidative stress in acute and chronic liver injury models. Additionally, the protein expression levels of pSmad2C and pSmad2L were decreased, but Nrf2 and HO-1 expression levels were increased both in vivo and in vitro. Collectively, the present results suggested that Sal B may protect against acute and chronic liver injury via inhibition of Smad2C/L phosphorylation, and the Nrf2/HO-1 signaling pathway may play an important role in this process.

Coenzyme Q10 and Silymarin Reduce CCl4-Induced Oxidative Stress and Liver and Kidney Injury in Ovariectomized Rats—Implications for Protective Therapy in Chronic Liver and Kidney Diseases

Oxidative stress is one of the key factors in the pathophysiology of liver disease. The present study aimed to evaluate the potential impact of two antioxidants, namely coenzyme Q10 (CoQ10) and silymarin, on carbon tetrachloride (CCl₄)-induced oxidative stress and hepatic damage in ovariectomized rats. Female Long Evans rats were divided into six groups (n = 6): control, CCl₄, CCl₄ + CoQ10 (200 mg/kg), CCl₄ + silymarin (140 mg/kg), Control + CoQ10, and Control + silymarin. Plasma and tissues from liver and kidney were analyzed for oxidative stress parameters and antioxidant enzyme activities using biochemical assays. Infiltration of inflammatory cells and fibrosis were assessed by histological staining of tissue sections. Both CoQ10 and silymarin significantly lowered serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), and alkaline phosphatase (ALP) levels that were detected to be higher in CCl₄ rats compared to controls. Significant reduction in CCl₄-induced elevated levels of oxidative stress markers malondialdehyde (MDA), nitric oxide (NO), and advanced protein oxidation product (APOP) was observed with both antioxidants. However, in control rats, CoQ10 and silymarin did not produce a significant effect. Histological analysis revealed that CCl₄ markedly increased the level of inflammatory cells infiltration and fibrosis in liver and kidney tissues, but this was significantly reduced in CCl₄ + CoQ10 and CCl₄ + silymarin groups. Taken together, our results suggest that CoQ10 and silymarin can protect the liver against oxidative damage through improved antioxidant enzyme activities and reduced lipid peroxidation. Thus, supplementation of the aforementioned antioxidants may be useful as a therapeutic intervention to protect liver health in chronic liver diseases.

Increasing Nrf2 Activity as a Treatment Approach in Neuropsychiatry

Nuclear factor erythroid 2-related factor 2 (Nrf2) is a transcription factor encoded by NFE2L2. Under oxidative stress, Nrf2 does not undergo its normal cytoplasmic degradation but instead travels to the nucleus, where it binds to a DNA promoter and initiates transcription of anti-oxidative genes. Nrf2 upregulation is associated with increased cellular levels of glutathione disulfide, glutathione peroxidase, glutathione transferases, thioredoxin and thioredoxin reductase. Given its key role in governing the cellular antioxidant response, upregulation of Nrf2 has been suggested as a common therapeutic target in neuropsychiatric illnesses such as major depressive disorder, bipolar disorder and schizophrenia, which are associated with chronic oxidative and nitrosative stress, characterised by elevated levels of reactive oxygen species, nitric oxide and peroxynitrite. These processes lead to extensive lipid peroxidation, protein oxidation and carbonylation, and oxidative damage to nuclear and mitochondrial DNA. Intake of N-acetylcysteine, coenzyme Q₁₀ and melatonin is accompanied by increased Nrf2 activity. N-acetylcysteine intake is associated with improved cerebral mitochondrial function, decreased central oxidative and nitrosative stress, reduced neuroinflammation, alleviation of endoplasmic reticular stress and suppression of the unfolded protein response. Coenzyme Q₁₀, which acts as a superoxide scavenger in neuroglial mitochondria, instigates mitohormesis, ameliorates lipid peroxidation in the inner mitochondrial membrane, activates uncoupling proteins, promotes mitochondrial biogenesis and has positive effects on the plasma membrane redox system. Melatonin, which scavenges mitochondrial free radicals, inhibits mitochondrial nitric oxide synthase, restores mitochondrial calcium homeostasis, deacetylates and activates mitochondrial SIRT3, ameliorates increased permeability of the blood-brain barrier and intestine and counters neuroinflammation and glutamate excitotoxicity.

Coenzyme Q10 attenuates inflammation and fibrosis implicated in radiation enteropathy through suppression of NF-kB/TGF-β/MMP-9 pathways

Radiation enteropathy is one the most common clinical issue for patients receiving radiotherapy for abdominal/pelvic tumors which severely affect the quality of life of cancer patients due to dysplastic lesions (ischemia, ulcer, or fibrosis) that aggravate the radiation damage. Herein, this study demonstrated the prophylactic role of coenzyme Q10 (CoQ10), a powerful antioxidant, against radiotherapy-induced gastrointestinal injury. Male Sprague Dawley rats were divided into four groups: group 1 was defined as control, and group 2 was the irradiated group. Group 3 and 4 were CoQ10 control and radiation plus CoQ10 groups, respectively. CoQ10 (10 mg/kg) was orally administered for 10 days before 10 Gy whole-body radiation and was continued for 4 days post-irradiation. CoQ10 administration protected rats delivered a lethal dose of ϒ-radiation from changes in crypt-villus structures and promoted regeneration of the intestinal epithelium. CoQ10 attenuated radiation-induced oxidative stress by decreasing lipid peroxidation and increasing the antioxidant enzyme catalase activity and reduced glutathione level. CoQ10 also counteracts inflammatory response mediated after radiation exposure through downregulating intestinal NF-ĸB expression which subsequently decreased the level of inflammatory cytokine IL-6 and the expression of COX-2. Radiation-induced intestinal fibrosis confirmed via Masson's trichrome staining occurred through upregulating transforming growth factor (TGF)-β1 and matrix metalloproteinase (MMP)-9 expression, while CoQ10 administration significantly diminishes these effects which further confirmed the anti-fibrotic property of CoQ10. Therefore, CoQ10 is a promising radioprotector that could prevent intestinal complications and enhance the therapeutic ratio of radiotherapy in patients with pelvic tumors through suppressing the NF-kB/TGF-β1/MMP-9 signaling pathway.

The interplay between oxidative stress and bioenergetic failure in neuropsychiatric illnesses: can we explain it and can we treat it?

Nitro-oxidative stress and lowered antioxidant defences play a key role in neuropsychiatric disorders such as major depression, bipolar disorder and schizophrenia. The first part of this paper details mitochondrial antioxidant mechanisms and their importance in reactive oxygen species (ROS) detoxification, including details of NO networks, the roles of H₂O₂ and the thioredoxin/peroxiredoxin system, and the relationship between mitochondrial respiration and NADPH production. The second part highlights and identifies the causes of the multiple pathological sequelae arising from self-amplifying increases in mitochondrial ROS production and bioenergetic failure. Particular attention is paid to NAD⁺ depletion as a core cause of pathology; detrimental effects of raised ROS and reactive nitrogen species on ATP and NADPH generation; detrimental effects of oxidative and nitrosative stress on the glutathione and thioredoxin systems; and the NAD⁺-induced signalling cascade, including the roles of SIRT1, SIRT3, PGC-1α, the FOXO family of transcription factors, Nrf1 and Nrf2. The third part discusses proposed therapeutic interventions aimed at mitigating such pathology, including the use of the NAD⁺ precursors nicotinamide mononucleotide and nicotinamide riboside, both of which rapidly elevate levels of NAD⁺ in the brain and periphery following oral administration; coenzyme Q₁₀ which, when given with the aim of improving mitochondrial function and reducing nitro-oxidative stress in the brain, may be administered via the use of mitoquinone, which is in essence ubiquinone with an attached triphenylphosphonium cation; and N-acetylcysteine, which is associated with improved mitochondrial function in the brain and produces significant decreases in oxidative and nitrosative stress in a dose-dependent manner.

Decellularized hepatic extracellular matrix hydrogel attenuates hepatic stellate cell activation and liver fibrosis

Liver fibrosis results from excessive accumulation of extracellular matrix (ECM) proteins that distort the hepatic architecture. Progression of liver fibrosis results in cirrhosis and liver failure, and often, liver transplantation is required. The decellularized liver tissue contains different components that mimic the natural hepatic environment. We hypothesized that a decellularized liver hydrogel can be used to replace the necrotic hepatocytes and damaged ECM. Therefore, our aim in this study is to develop a therapy for treating liver fibrosis. Mice livers were decellularized and processed to form a hepatic hydrogel. We evaluated the biocompatibility and bioactivity of the hydrogel. The ability of the hydrogel to enhance the migration of hepatocytes and endothelial cells was investigated. Human hepatic stellate cell line (LX-2) activated by transforming growth factor-β1 (TGF-β1) was used as in vitro model for fibrogenesis. Then, the hydrogel was injected into the liver parenchyma of mice after the induction of liver fibrosis using thioacetamide. The resulting hydrogel maintained a complex composition, which included glycosaminoglycans, collagen, elastin, and growth factors. Hepatocytes and endothelial cells were shown to migrate toward the hydrogel in vitro. Liver hydrogel improved TGF-β1-induced LX-2 cells activation via blocking the TGF-β1/Smad pathway. The matrix was delivered successfully in vivo and enhanced the reduction of fibrosis and recovery to a nearly normal structure. In conclusion, we have demonstrated that the liver hydrogel can be utilized as an injectable biomaterial for liver tissue engineering in order to reduce the degree of fibrosis.

Coenzyme Q10 supplementation in non-alcoholic fatty liver disease: an overview

Non-alcoholic fatty liver disease (NAFLD) is the most common liver disorder in the UK, for which little effective conventional treatment is available. Mitochondrial dysfunction, oxidative stress and inflammation have been implicated in the pathogenesis of NAFLD. This article focuses on the role of the vitamin-like substance coenzyme Q10 (CoQ10) in NAFLD, since CoQ10 plays a key role in mitochondrial function, as well as having antioxidant and anti-inflammatory action. CoQ10 levels are depleted in NAFLD, and studies in animal models and human subjects have indicated that supplementation with CoQ10 can significantly reduce oxidative stress and the inflammation characteristic of NAFLD. In addition, NAFLD patients are at increased risk of developing heart failure, and supplementary CoQ10 may help to reduce this risk. Supplementary CoQ10 is generally well tolerated, with no significant adverse effects reported in long-term use.

Salvianolic acid B exerts a protective effect in acute liver injury by regulating the Nrf2/HO-1 signaling pathway

Salvianolic acid B (Sal B) exerts strong antioxidant activity and eliminates the free radical effect. However, how it affects the antioxidant pathway is not very clear. The objective of this study was to investigate the underlying mechanism of Sal B in CCl4-induced acute liver injury, especially its effect on the Nrf2/HO-1 signaling pathway. For the in vivo experiment, an acute liver injury model was induced using CCl4 and treated with Sal B. For the in vitro experiment, an oxidative damage model was established followed by Sal B treatment. Serum biochemical indicators and reactive oxygen species activity were detected using corresponding kits. Oxidant/antioxidant status was determined based on the levels of malondialdehyde, glutathione, and superoxide dismutase. Nrf2 and HO-1 levels were analyzed by Western blotting and immunohistochemical staining. Sal B treatment improved liver histology, decreased the aminotransferase levels, and attenuated oxidative stress in the acute liver injury model. Nrf2 and HO-1 levels were increased both in vivo and in vitro. Sal B suppresses acute liver injury and Nrf2/HO-1 signaling plays a key role in this process.

The compensatory antioxidant response system with a focus on neuroprogressive disorders

Major antioxidant responses to increased levels of inflammatory, oxidative and nitrosative stress (ONS) are detailed. In response to increasing levels of nitric oxide, S-nitrosylation of cysteine thiol groups leads to post-transcriptional modification of many cellular proteins and thereby regulates their activity and allows cellular adaptation to increased levels of ONS. S-nitrosylation inhibits the function of nuclear factor kappa-light-chain-enhancer of activated B cells, toll-like receptor-mediated signalling and the activity of several mitogen-activated protein kinases, while activating nuclear translocation of nuclear factor (erythroid-derived 2)-like 2 (Nrf2 or NFE2L2); in turn, the redox-regulated activation of Nrf2 leads to increased levels and/or activity of key enzymes and transporter systems involved in the glutathione system. The Nrf2/Kelch-like ECH-associated protein-1 axis is associated with upregulation of NAD(P)H:quinone oxidoreductase 1, which in turn has anti-inflammatory effects. Increased Nrf2 transcriptional activity also leads to activation of haem oxygenase-1, which is associated with upregulation of bilirubin, biliverdin and biliverdin reductase as well as increased carbon monoxide signalling, anti-inflammatory and antioxidant activity. Associated transcriptional responses, which may be mediated by retrograde signalling owing to elevated hydrogen peroxide, include the unfolded protein response (UPR), mitohormesis and the mitochondrial UPR; the UPR also results from increasing levels of mitochondrial and cytosolic reactive oxygen species and reactive nitrogen species leading to nitrosylation, glutathionylation, oxidation and nitration of crucial cysteine and tyrosine causing protein misfolding and the development of endoplasmic reticulum stress. It is shown how these mechanisms co-operate in forming a co-ordinated rapid and prolonged compensatory antioxidant response system.

Targeting Oxidative Stress for the Treatment of Liver Fibrosis

Oxidative stress is a reflection of the imbalance between the production of reactive oxygen species (ROS) and the scavenging capacity of the antioxidant system. Excessive ROS, generated from various endogenous oxidative biochemical enzymes, interferes with the normal function of liver-specific cells and presumably plays a role in the pathogenesis of liver fibrosis. Once exposed to harmful stimuli, Kupffer cells (KC) are the main effectors responsible for the generation of ROS, which consequently affect hepatic stellate cells (HSC) and hepatocytes. ROS-activated HSC undergo a phenotypic switch and deposit an excessive amount of extracellular matrix that alters the normal liver architecture and negatively affects liver function. Additionally, ROS stimulate necrosis and apoptosis of hepatocytes, which causes liver injury and leads to the progression of end-stage liver disease. In this review, we overview the role of ROS in liver fibrosis and discuss the promising therapeutic interventions related to oxidative stress. Most importantly, novel drugs that directly target the molecular pathways responsible for ROS generation, namely, mitochondrial dysfunction inhibitors, endoplasmic reticulum stress inhibitors, NADPH oxidase (NOX) inhibitors, and Toll-like receptor (TLR)-affecting agents, are reviewed in detail. In addition, challenges for targeting oxidative stress in the management of liver fibrosis are discussed.

Coenzyme Q10 and Degenerative Disorders Affecting Longevity: An Overview

Longevity is determined by a number of factors, including genetic, environmental and lifestyle factors. A major factor affecting longevity is the development of degenerative disorders such as cardiovascular disease, diabetes, kidney disease and liver disease, particularly where these occur as co-morbidities. In this article, we review the potential role of supplementation with coenzyme Q10 (CoQ10) for the prevention or management of these disorders. Thus, randomised controlled clinical trials have shown supplementation with CoQ10 or CoQ10 plus selenium reduces mortality by approximately 50% in patients with cardiovascular disease, or in the normal elderly population, respectively. Similarly, CoQ10 supplementation improves glycaemic control and vascular dysfunction in type II diabetes, improves renal function in patients with chronic kidney disease, and reduces liver inflammation in patients with non-alcoholic fatty liver disease. The beneficial role of supplemental CoQ10 in the above disorders is considered to result from a combination of its roles in cellular energy generation, as an antioxidant and as an anti-inflammatory agent.

Activation of Nrf2 signaling by natural products-can it alleviate diabetes?

Type 2 diabetes mellitus (DM) has reached pandemic proportions and effective prevention strategies are wanted. Its onset is accompanied by cellular distress, the nuclear factor erythroid 2-related factor 2 (Nrf2) is a transcription factor boosting cytoprotective responses, and many phytochemicals activate Nrf2 signaling. Thus, Nrf2 activation by natural products could presumably alleviate DM. We summarize function, regulation and exogenous activation of Nrf2, as well as diabetes-linked and Nrf2-susceptible forms of cellular stress. The reported amelioration of insulin resistance, β-cell dysfunction and diabetic complications by activated Nrf2 as well as the status quo of Nrf2 in precision medicine for DM are reviewed.

Molecular mechanisms of neuroprotective effect of adjuvant therapy with phenytoin in pentylenetetrazole-induced seizures: Impact on Sirt1/NRF2 signaling pathways

Current anticonvulsant therapies are principally aimed at suppressing neuronal hyperexcitability to prevent or control the incidence of seizures. However, the role of oxidative stress processes in seizures led to the proposition that antioxidant compounds may be considered as promising candidates for limiting the progression of epilepsy. Accordingly, the aim of this study is to determine if coenzyme Q10 (CoQ10) and alpha-tocopherol (α-Toc) have a neuroprotective effect in rats against the observed oxidative stress and inflammation during seizures induced by pentylenetetrazole (PTZ) in rats, and to study their interactions with the conventional antiseizure drug phenytoin (PHT), either alone or in combination. Overall, the data revealed that α-Toc and CoQ10 supplementation can ameliorate PTZ-induced seizures and recommended that nuclear factor erythroid 2-related factor 2 (NRF2) and silencing information regulator 1 (Sirt1) signaling pathways may exemplify strategic molecular targets for seizure therapies. The results of the present study provide novel mechanistic insights regarding the protective effects of antioxidants and suggest an efficient therapeutic strategy to attenuate seizures. Additionally, concurrent supplementation of CoQ10 and α-Toc may be more effective than either antioxidant alone in decreasing inflammation and oxidative stress in both cortical and hippocampal tissues. Also, CoQ10 and α-Toc effectively reverse the PHT-mediated alterations in the brain antioxidant status when compared to PHT only.

Acetone fraction from Sechium edule (Jacq.) S.w. edible roots exhibits anti-endothelial dysfunction activity

ETHNOPHARMACOLOGICAL RELEVANCE

A recent ethnomedical survey on medicinal plants grown in Mexico revealed that Sechium edule (Jacq.) Sw. (Cucurbitaceae) is one of the most valued plant species to treat cardiovascular diseases, including hypertension. Fruits, young leaves, buds, stems, and tuberous roots of the plant are edible. Considering that endothelial dysfunction induced by Angiotensin II plays an important role in the pathogenesis of hypertension and is accompanied by a prooxidative condition, which in turn induces an inflammatory state, vascular remodeling, and tissue damage, and that S. edule has been reported to possess antioxidant, anti-inflammatory and antihypertensive activity, its capability to control endothelial dysfunction was also assessed.

AIM OF THE STUDY

To assess in vivo the anti-endothelial dysfunction activity of the acetone fraction (rSe-ACE) of the hydroalcoholic extract from S. edule roots.

MATERIALS AND METHODS

Endothelial dysfunction was induced in female C57BL/6 J mice by a daily intraperitoneal injection of angiotensin II for 10 weeks. Either rSe-ACE or losartan (as a control) were co-administered with angiotensin II for the same period. Blood pressure was measured at weeks 0, 5, and 10. Kidney extracts were prepared to determine IL1β, IL4, IL6, IL10, IL17, IFNγ, TNFα, and TGFβ levels by ELISA, along with the prooxidative status as assessed by the activity of antioxidant enzymes. The expression of ICAM-1 was evaluated by immunohistochemistry in kidney histological sections. Kidney and hepatic damage, as well as vascular tissue remodeling, were studied.

RESULTS

The rSe-ACE fraction administered at a dose of 10 mg/kg was able to control hypertension, as well as the prooxidative and proinflammatory status in kidney as efficiently as losartan, returning mice to normotensive levels. Additionally, the fraction was more efficient than losartan to prevent liver and kidney damage. Phytochemical characterization identified cinnamic acid as a major compound, and linoleic, palmitic, and myristic acids as the most abundant non-polar components in the mixture, previously reported to aid in the control of hypertension, inflammation, and oxidative stress, three important components of endothelial dysfunction.

IN CONCLUSION

this study demonstrated that rSe-ACE has anti-endothelial dysfunction activity in an experimental model and highlights the role of cinnamic acid and fatty acids in the observed effects.

Rosuvastatin improves myocardial hypertrophy after hemodynamic pressure overload via regulating the crosstalk of Nrf2/ARE and TGF-β/ smads pathways in rat heart

Left ventricular hypertrophy is more commonly associated with hemodynamic overload imposed by hypertension or volume overload. Transforming growth factor β (TGF-β) is involved in the cardiac hypertrophy and fibrosis of the left ventricle. The fact that TGF-β1 and the nuclear factor erythroid 2-related factor 2 (Nrf2) both become up-regulated upon persistent vessel overload suggests that these two factors may virtually impact on their signaling pathways. In this research, 40 rats were divided into sham group, model group, rosuvastatin low and high dose group. Rat models were established by incomplete constriction of abdominal aorta. After five weeks treatment, blood pressure, heart mass index (HMI), hemodynamic parameters and the average diameter of myocardium cell and collagen volume fraction (CVF) improved significantly in rosuvastatin groups, compared with the model group. Both rosuvastatin groups, increased in expression of Smad7, Nrf2, NAD (P) H dehydrogenase [quinone] 1 (Nqo1) and heme oxygenase 1(Ho1),and decreased in expression of TGF-βl、Smad3 compared with the model group. Results from co-immunoprecipitation and GST pull down showed that Nrf2 interacts with Smad7. Our results revealed the crosstalk between TGF-β1/Smads and Nrf2/ antioxidant response elements (ARE) pathways in myocardial remodeling through the interaction between Smad7 and Nrf2. Rosuvastatin can improve cardiac function and hypertrophy by regulating the crosstalk of the two signaling pathways.

Self-Nanoemulsifying Drug Delivery System of Coenzyme (Q10) with Improved Dissolution, Bioavailability, and Protective Efficiency on Liver Fibrosis

The aim of our investigation is to develop and characterize self-nanoemulsifying drug delivery systems (SNEDDS) of CoQ₁₀ to improve its water solubility, dissolution rate, and bioavailability, and then evaluate its biochemical and physiological effect on liver cirrhosis in rats compared with CoQ₁₀ powder. SNEDDS are isotropic and thermodynamically stable mixture of oil, surfactant, co-surfactant, and drug that form an oil/water nanoemulsion when added to aqueous phases with soft agitation. Upon administration, self-nanoemulsifying system becomes in contact with gastrointestinal fluid and forms o/w nanoemulsion by the aid of gastrointestinal motility. When the nanoemulsion is formed in the gastrointestinal tract, it presents the drug in a solubilized form inside small nano-sized droplets that provide a large surface area for enhancing the drug release and absorption. Solubility of CoQ₁₀ in various oils, surfactants, and co-surfactants were studied to identify the components of SNEDDS; pseudo-ternary phase diagrams were plotted to identify the efficient self-emulsifying regions. CoQ₁₀-loaded SNEDDS were prepared using isopropyl myristate as oil; Cremophor El, Labrasol, or Tween80 as surfactant; and Transcutol as co-surfactant. The amount of CoQ₁₀ in each vehicle was 3%. The formulations that passed thermostability evaluation test were assessed for particle size analysis, morphological characterization, refractive index, zeta potential, viscosity, electroconductivity, drug release profile, as well as ex vivo permeability. Pharmacokinetics and hepatoprotective efficiency of the optimized SNEDDS of CoQ₁₀ compared with CoQ₁₀ suspension were performed. Results showed that all optimized formulae have the ability to form a good and stable nanoemulsion when diluted with water; the mean droplet size of all formulae was in the nanometric range (11.7-13.5 nm) with optimum polydispersity index values (0.2-0.21). All formulae showed negative zeta potential (-11.3 to -17.2), and maximum drug loading efficiency. One hundred percent of CoQ₁₀ was released from most formulae within 30 min. One hundred percent of CoQ₁₀ was permeated from all formulae through 10 h. The pharmacokinetic study in rabbits revealed a significant increase in bioavailability of CoQ₁₀ SNEDDS to 2.1-fold compared with CoQ₁₀ suspension after oral administration. Comparative effect of the optimized formulae on acute liver injury compared with CoQ₁₀ powder was also studied; it was found that all the liver biochemical markers as alanine transferase (ALT), aspartate amino transferase (AST), alkaline phosphatase (ALP), total protein (TP), and albumin were significantly improved at p < 0.05. Also, histochemical and histopthological studies confirm the biochemical results. Our results suggest the potential use of SNEDDS to increase the solubility of liphophilic drug as poorly water-soluble CoQ₁₀ and improve its oral absorption, so it can be more efficient to improve liver damage compared to CoQ₁₀ powder. These results demonstrated that CoQ₁₀ SNEDDS inhibited thioacetamide (TAA)-induced liver fibrosis mainly through suppression of collagen production.

Natural antioxidants in the treatment and prevention of diabetic nephropathy; a potential approach that warrants clinical trials

Diabetic nephropathy is the major cause of end-stage renal disease and effective and new therapeutic approaches are needed in diabetic nephropathy and chronic kidney diseases. Oxidative stress and inflammatory process are important factors contributing to kidney damage by increasing production of oxidants. KEAP1/Nrf2/ARE pathway regulates the transcription of many antioxidant genes and modulation of the pathway up regulates antioxidants. NFB controls the expression of genes involved in the inflammatory response. Natural substances have antioxidant and anti-inflammatory activities and have an impact on NFB and KEAP1/Nrf2/ARE pathways. The preclinical studies explored the effectiveness of whole herbs, plants or seeds and their active ingredients in established diabetic nephropathy. They ameliorate oxidative stress induced kidney damage, enhance antioxidant system, and decrease inflammatory process and fibrosis; most likely by activating KEAP1/Nrf2/ARE pathway and by deactivating NFB pathway. Whole natural products contain balanced antioxidants that might work synergistically to induce beneficial therapeutic outcome. In this context, more clinical studies involving whole plants or herbal products or mixtures of different herbs and plants and their active ingredients might change our strategies for the management of diabetic nephropathy. The natural products might be useful as preventive interventions and studies are required in this field.

Nature and Implications of Oxidative and Nitrosative Stresses in Autoimmune Hepatitis

Oxidative and nitrosative stresses can damage cellular membranes, disrupt mitochondrial function, alter gene expression, promote the apoptosis and necrosis of hepatocytes, and increase fibrosis in diverse acute and chronic liver diseases, including autoimmune hepatitis. The objectives of this review are to describe the mechanisms of oxidative and nitrosative stresses in inflammatory liver disease, indicate the pathogenic implications of these stresses in autoimmune hepatitis, and suggest investigational opportunities to develop interventions that counter them. The principal antioxidant defenses, including glutathione production, the activities of antioxidant enzymes, and the release of the nuclear factor erythroid 2-related factor 2, may be inadequate or suppressed by transforming growth factor beta. The generation of reactive oxygen species can intensify nitrosative stress, and this stress may not be adequately modulated by the thioredoxin-thioredoxin reductase system and induce post-translational modifications of proteins that further disrupt hepatocyte function. The unfolded protein response and autophagy may be unable to restore redox stability, meet metabolic demands, and maintain hepatocyte survival. Emerging interventions with highly selective site- and organelle-specific actions may improve outcomes, and they include inhibitors of nicotinamide adenine dinucleotide phosphate oxidase, nitric oxide synthase, and transforming growth factor beta. Pharmacological manipulation of nuclear transcription factors may favor expression of antioxidant genes, and stimulation of chaperone proteins within the endoplasmic reticulum and modulation of autophagy may prevent hepatic fibrosis and enhance cell survival. These interventions constitute investigational opportunities to improve the management of autoimmune hepatitis.

Protective Effects of Berberine on Renal Injury in Streptozotocin (STZ)-Induced Diabetic Mice

Diabetic nephropathy (DN) is a serious diabetic complication with renal hypertrophy and expansion of extracellular matrices in renal fibrosis. Epithelial-to-mesenchymal transition (EMT) of renal tubular epithelial cells may be involved in the main mechanism. Berberine (BBR) has been shown to have antifibrotic effects in liver, kidney and lung. However, the mechanism of cytoprotective effects of BBR in DN is still unclear. In this study, we investigated the curative effects of BBR on tubulointerstitial fibrosis in streptozotocin (STZ)-induced diabetic mice and the high glucose (HG)-induced EMT in NRK 52E cells. We found that BBR treatment attenuated renal fibrosis by activating the nuclear factor-erythroid 2-related factor 2 (Nrf2) signaling pathway in the diabetic kidneys. Further revealed that BBR abrogated HG-induced EMT and oxidative stress in relation not only with the activation of Nrf2 and two Nrf2-targeted antioxidative genes (NQO-1 and HO-1), but also with the suppressing the activation of TGF-β/Smad signaling pathway. Importantly, knockdown Nrf2 with siRNA not only abolished the BBR-induced expression of HO-1 and NQO-1 but also removed the inhibitory effect of BBR on HG-induced activation of TGF-β/Smad signaling as well as the anti-fibrosis effects. The data from present study suggest that BBR can ameliorate tubulointerstitial fibrosis in DN by activating Nrf2 pathway and inhibiting TGF-β/Smad/EMT signaling activity.

Effects of siRNA-Mediated Knockdown of HDAC1 on the Biological Behavior of Esophageal Carcinoma Cell Lines

BACKGROUND HDAC1 has been shown to be closely associated with the occurrence of tumors. We aimed to investigate the effects of siRNA-mediated HDAC1 knockdown on the biological behavior of esophageal carcinoma cell lines. MATERIAL AND METHODS HDAC1 expression in esophageal cancer cell lines TE-1, Eca109, and EC9706 was compared by Western blot analysis. These cells were transfected with siRNA-HDAC1 and cell proliferation was evaluated by MTT assay to select the optimum cell line for subsequent experiments. The effects of siRNA-HDAC1 on the migration and invasion of the selected cell line were assessed by transwell assay. The expression of cell cycle-related proteins cyclinD1, p21 and p27, and epithelial-mesenchymal transition (EMT)-related protein zonula occludens-1 (ZO-1), E-cadherin and vimentin was determined by Western blot analysis. RESULTS HDAC1 expression in TE-1, Eca109 and EC9706 cells was significantly higher compared with normal esophageal cell line HEEC (P<0.01). MTT assay, Western blot and RT-PCR analyses demonstrated that the inhibitory effects of siRNA on HDAC1 expression and cell viability in TE-1 cells were the highest among all cell lines, which was therefore used in subsequent experiments. After TE-1 cells were transfected with siRNA-HDAC1, their migration and invasion were significantly lower compared with the controls (P<0.01). CyclinD1 and vimentin expression was significantly lower compared with the controls (P<0.01), whereas the expression of p21, p27, ZO-1 and E-cadherin was significantly higher (P<0.01). CONCLUSIONS The siRNA-mediated HDAC1 knockdown significantly inhibited the proliferation, migration and invasion of TE-1 cells probably by regulating the expression of cell cycle- and EMT-related proteins.

The anti-oxidative transcription factor Nuclear factor E2 related factor-2 (Nrf2) counteracts TGF-β1 mediated growth inhibition of pancreatic ductal epithelial cells -Nrf2 as determinant of pro-tumorigenic functions of TGF-β1

BACKGROUND

Nuclear factor E2 related factor-2 (Nrf2) is an oxidative stress inducible transcription factor being essential in regulating cell homeostasis. Thus, acute induction of Nrf2 in epithelial cells exposed to inflammation confers protection from oxidative cell damage and mutagenesis supporting an anti-tumorigenic role for Nrf2. However, pancreatic ductal adenocarcinoma (PDAC) is characterized by persistent Nrf2 activity conferring therapy resistance which points to a pro-tumorigenic role of Nrf2. A similar dichotomous role in tumorigenesis is described for the Transforming Growth Factor-beta 1 (TGF-β1). The present study therefore aimed at elucidating whether the switch of Nrf2 function towards a tumor promoting one relates to the modulation of TGF-β1 induced cell responses and whether this might occur early in PDAC development.

METHODS

In situ analysis comprised immunohistochemical stainings of activated (phosphorylated) Nrf2 and Ki67 in pancreatic tissues containing normal ducts and pancreatic intraepithelial neoplasia (PanINs). In vitro, Nrf2 levels in benign (H6c7-pBp), premalignant (H6c7-kras) and malignant (Colo357) pancreatic ductal epithelial cells were modulated by Nrf2 specific siRNA or Nrf2 overexpression. Then, the effect of Nrf2 alone and in combination with TGF-β1 on cell growth and survival was investigated by cell counting, Ki67 staining and apoptosis assays. The underlying cell signaling was investigated by western blotting. Statistical analysis was performed by Shapiro-Wilk test for normal distribution. Parametric data were analyzed by one-way ANOVA, while non-parametric data were analyzed by Kruskal-Wallis one-way ANOVA on ranks.

RESULTS

Significantly elevated expression of activated Nrf2 and Ki67 could be detected in PanINs but not in normal pancreatic ductal epithelium. While the effect of Nrf2 on basal cell growth of H6c7-pBp, H6c7-kras and Colo357 cells was minor, it clearly attenuated the growth inhibiting effects of TGF-β1 in all cell lines. This enhanced Nrf2-mediated cell survival was predominantly based on an enhanced proliferative activity. Accordingly, expression of p21 expression along with expression of phospho-p38 and phospho-Smad3 was diminished whereas Erk-phosphorylation was enhanced under these conditions.

CONCLUSIONS

Overall, our data demonstrate that Nrf2 being elevated in early precursor lesions counteracts the growth inhibiting function of TGF-β1 already in benign and premalignant pancreatic ductal epithelial cells. This could represent one fundamental mechanism underlying the functional switch of both- TGF-β1 and Nrf2 - which may manifest already in early stages of PDAC development.

Coenzyme Q10 prevents hepatic fibrosis, inflammation, and oxidative stress in a male rat model of poor maternal nutrition and accelerated postnatal growth

BACKGROUND

It is well established that low birth weight and accelerated postnatal growth increase the risk of liver dysfunction in later life. However, molecular mechanisms underlying such developmental programming are not well characterized, and potential intervention strategies are poorly defined.

OBJECTIVES

We tested the hypotheses that poor maternal nutrition and accelerated postnatal growth would lead to increased hepatic fibrosis (a pathological marker of liver dysfunction) and that postnatal supplementation with the antioxidant coenzyme Q10 (CoQ10) would prevent this programmed phenotype.

DESIGN

A rat model of maternal protein restriction was used to generate low-birth-weight offspring that underwent accelerated postnatal growth (termed "recuperated"). These were compared with control rats. Offspring were weaned onto standard feed pellets with or without dietary CoQ10 (1 mg/kg body weight per day) supplementation. At 12 mo, hepatic fibrosis, indexes of inflammation, oxidative stress, and insulin signaling were measured by histology, Western blot, ELISA, and reverse transcriptase-polymerase chain reaction.

RESULTS

Hepatic collagen deposition (diameter of deposit) was greater in recuperated offspring (mean ± SEM: 12 ± 2 μm) than in controls (5 ± 0.5 μm) (P < 0.001). This was associated with greater inflammation (interleukin 6: 38% ± 24% increase; P < 0.05; tumor necrosis factor α: 64% ± 24% increase; P < 0.05), lipid peroxidation (4-hydroxynonenal, measured by ELISA: 0.30 ± 0.02 compared with 0.19 ± 0.05 μg/mL per μg protein; P < 0.05), and hyperinsulinemia (P < 0.05). CoQ10 supplementation increased (P < 0.01) hepatic CoQ10 concentrations and ameliorated liver fibrosis (P < 0.001), inflammation (P < 0.001), some measures of oxidative stress (P < 0.001), and hyperinsulinemia (P < 0.01).

CONCLUSIONS

Suboptimal in utero nutrition combined with accelerated postnatal catch-up growth caused more hepatic fibrosis in adulthood, which was associated with higher indexes of oxidative stress and inflammation and hyperinsulinemia. CoQ10 supplementation prevented liver fibrosis accompanied by downregulation of oxidative stress, inflammation, and hyperinsulinemia.

Simultaneous activation of Nrf2 and elevation of antioxidant compounds for reducing oxidative stress and chronic inflammation in human Alzheimer's disease

Despite extensive research, neither the incidence nor the rate of progression of Alzheimer's disease (AD) has significantly changed. Some biochemical and genetic defects that initiate and promote AD include: (a) increased oxidative stress, (b) chronic inflammation (c) mitochondrial dysfunction, (d) Aß1-42 peptides generated from the amyloid precursor protein (APP), (e) proteasome inhibition, and (f) mutations in APP, presenilin-1 and presenilin-2 genes. Increased oxidative stress appears to precede other biochemical and genetic defects. Oxidative damage induces chronic inflammation. Therefore, reducing these defects simultaneously may reduce the development and progression of AD. Previous studies with individual antioxidants produced consistent benefits in animal models of AD; however, a similar approach produced inconsistent results in human AD. This review proposes a hypothesis that simultaneous elevation of the levels of antioxidant enzymes and antioxidant compounds is necessary for optimally reducing oxidative stress and chronic inflammation in human AD. Supplementation can enhance the levels of antioxidant compounds; but elevation of antioxidant enzymes requires activation of Nrf2. This review discusses activation and regulation of Nrf2. The need for multi- antioxidants that can affect multi-targets has been proposed without specific recommendations. This review proposes a micronutrient mixture that would simultaneously enhance the levels of antioxidant enzymes and antioxidant compounds in human AD.

The Emerging Role of Disturbed CoQ Metabolism in Nonalcoholic Fatty Liver Disease Development and Progression

Although non-alcoholic fatty liver disease (NAFLD), characterised by the accumulation of triacylglycerol in the liver, is the most common liver disorder, the causes of its development and progression to the more serious non-alcoholic steatohepatitis (NASH) remain incompletely understood. Oxidative stress has been implicated as a key factor in both these processes, and mitochondrial dysfunction and inflammation are also believed to play a part. Coenzyme Q (CoQ) is a powerful antioxidant found in all cell membranes which has an essential role in mitochondrial respiration and also has anti-inflammatory properties. NAFLD has been shown to be associated with disturbances in plasma and liver CoQ concentrations, but the relationship between these changes and disease development and progression is not yet clear. Dietary supplementation with CoQ has been found to be hepatoprotective and to reduce oxidative stress and inflammation as well as improving mitochondrial dysfunction, suggesting that it may be beneficial in NAFLD. However, studies using animal models or patients with NAFLD have given inconclusive results. Overall, evidence is now emerging to indicate that disturbances in CoQ metabolism are involved in NAFLD development and progression to NASH, and this highlights the need for further studies with human subjects to fully clarify its role.