Decreased mitochondrial deoxyribonucleic acid and increased oxidative damage in chronic hepatitis C

Mitochondrial DNA copy number in Hepatitis C virus-related chronic liver disease: impact of direct-acting antiviral therapy

Hepatitis C virus (HCV) infection can regulate the number and dynamics of mitochondria, and is associated with a prominent hepatic mitochondrial injury. Mitochondrial distress conveys oxidative damage which is implicated in liver disease progression. The present study was conducted to assess the change of mitochondrial DNA (mtDNA) copy number in patients with HCV-related chronic liver disease and the impact of direct-acting antiviral (DAA) therapy. Whole blood mtDNA copy number was measured using real-time quantitative polymerase chain reaction at baseline and 12 weeks after the end of therapy in 50 treatment-naïve HCV-infected patients who achieved sustained viral response (SVR) after DAA therapy and 20 healthy controls. Whole blood mtDNA copy number appeared significantly lower in HCV-infected patients before therapy compared to healthy subjects (P < 0.001). Post-treatment, there was significant increase of mtDNA copy number in HCV-infected patients at SVR12 compared to the pre-treatment values (P < 0.001), meanwhile it didn't differ significantly between HCV-infected patients after therapy and healthy subjects (P = 0.059). Whole blood mtDNA copy number correlated inversely to the serum bilirubin in HCV-infected patients (P = 0.013), however it didn't correlate significantly to the serum aminotransferases, viral load or fibrosis-4 score (P > 0.05). In conclusion, chronic HCV infection has been associated with a prominent mitochondrial injury which could mediate a progressive liver disease. The improved mtDNA content after DAA therapy highlights a possible potential of these drugs to alleviate mitochondrial damage in HCV-related liver disease.

Mitochondrial DNA content as a diagnostic marker for anti-tuberculosis drug-induced liver injury

OBJECTIVES

This study aimed to investigate whether mitochondrial DNA (mtDNA) content, an index of mitochondrial dysfunction, was associated with clinical parameters indicating ATDILI in TB patients and could emerge as an ATDILI biomarker.

METHODS

Leukocyte mtDNA content in 102 TB patients (49 ATDILI cases and 53 non-ATDILI cases) and 100 age-matched healthy controls was measured using real-time PCR.

RESULTS

Compared to healthy controls, both TB patients with and without ATDILI had significantly decreased mtDNA content. Compared with non-ATDILI patients, mtDNA content was significantly increased in ATDILI patients. Higher mtDNA content was observed to be independently associated with increased susceptibility to ATDILI. Increased mtDNA content measured within 1-7 days of treatment was independently associated with elevated levels of serum aminotransferases assessed within 8-60 days of treatment. After initiating treatment within 1-7 days, mtDNA content was detected to be more sensitive and selective for differentiating ATDILI patients from those without ATDILI than serum aminotransferases. Kaplan-Meier analysis revealed a significant correlation between elevated mtDNA content and increased rate of ATDILI occurrence in TB patients, attested by Cox regression analysis with adjusting for confounders.

CONCLUSION

Changes in leukocyte mtDNA content would reflect ATDILI progression and could be used as a potential stratification tool for identifying TB patients at risk of ADTILI.

Pan-Genotypic Direct-Acting Antiviral Agents for Undetermined or Mixed-Genotype Hepatitis C Infection: A Real-World Multi-Center Effectiveness Analysis

Although the pan-genotypic direct-acting antiviral regimen was approved for treating chronic hepatitis C infection regardless of the hepatitis C virus (HCV) genotype, real-world data on its effectiveness against mixed-genotype or genotype-undetermined HCV infection are scarce. We evaluated the real-world safety and efficacy of two pan-genotypic regimens (Glecaprevir/Pibrentasvir and Sofosbuvir/Velpatasvir) for HCV-infected patients with mixed or undetermined HCV genotypes from the five hospitals in the Changhua Christian Care System that commenced treatment between August 2018 and December 2020. This retrospective study evaluated the efficacy and safety of pan-genotypic direct-acting antiviral (DAA) treatment in adults with HCV infection. The primary endpoint was the sustained virological response (SVR) observed 12 weeks after completing the treatment. Altogether, 2446 HCV-infected patients received the pan-genotypic DAA regimen, 37 (1.5%) patients had mixed-genotype HCV infections and 110 (4.5%) patients had undetermined HCV genotypes. The mean age was 63 years and 55.8% of our participants were males. Nine (6.1%) patients had end-stage renal disease and three (2%) had co-existing hepatomas. We lost one patient to follow-up during treatment and one more patient after treatment. A total of four patients died. However, none of these losses were due to treatment-related side effects. The rates of SVR12 for mixed-genotype and genotype-undetermined infections were 97.1% and 96.2%, respectively, by per-protocol analyses, and 91.9% and 92.7% respectively, by intention-to-treat population analyses. Laboratory adverse events with grades ≥3 included anemia (2.5%), thrombocytopenia (2.5%), and jaundice (0.7%). Pan-genotypic DAAs are effective and well-tolerated for mixed-genotype or genotype-undetermined HCV infection real-world settings.

Human studies of mitochondrial biology demonstrate an overall lack of binary sex differences: A multivariate meta-analysis

Mitochondria are maternally inherited organelles that play critical tissue-specific roles, including hormone synthesis and energy production, that influence human development, health, and aging. However, whether mitochondria from women and men exhibit consistent biological differences remains unclear, representing a major gap in knowledge. This meta-analysis systematically examined four domains and six subdomains of mitochondrial biology (total 39 measures), including mitochondrial content, respiratory capacity, reactive oxygen species (ROS) production, morphometry, and mitochondrial DNA copy number. Standardized effect sizes (Hedge's g) of sex differences were computed for each measure using data in 2258 participants (51.5% women) from 50 studies. Only two measures demonstrated aggregate binary sex differences: higher mitochondrial content in women's WAT and isolated leukocyte subpopulations (g = 0.20, χ² p = .01), and higher ROS production in men's skeletal muscle (g = 0.49, χ² p < .0001). Sex differences showed weak to no correlation with age or BMI. Studies with small sample sizes tended to overestimate effect sizes (r = -.17, p < .001), and sex differences varied by tissue examined. Our findings point to a wide variability of findings in the literature concerning possible binary sex differences in mitochondrial biology. Studies specifically designed to capture sex- and gender-related differences in mitochondrial biology are needed, including detailed considerations of physical activity and sex hormones.

Real-World Experience of Chronic Hepatitis C-Related Compensated Liver Cirrhosis Treated with Glecaprevir/Pibrentasvir: A Multicenter Retrospective Study

Background: Glecaprevir/pibrentasvir is a protease inhibitor-containing pangenotypic direct-acting antiviral regimen that has been approved for the treatment of chronic hepatitis C. The present study aimed to evaluate the safety and efficacy of glecaprevir/pibrentasvir in patients with compensated cirrhosis in a real-world setting. Methods: We evaluated the real-world safety and efficacy of glecaprevir/pibrentasvir in patients with compensated cirrhosis from five hospitals in the Changhua Christian Care System, who underwent treatment between August 2018 and October 2020. The primary endpoint was a sustained virological response observed 12 weeks after completion of the treatment. Results: Ninety patients, including 70 patients who received the 12-week therapy and 20 patients who received the 8-week therapy, were enrolled. The mean age of the patients was 65 years, and 57.8% of the patients were males. Sixteen (17.8%) patients had end-stage renal disease, and 15 (16.7%) had co-existing hepatoma. The hepatitis C virus genotypes 1 (40%) and 2 (35.6%) were most common. The common side effects included anorexia (12.2%), pruritus (7.8%), abdominal discomfort (7.8%), and malaise (7.8%). Laboratory adverse grade ≥3 events included anemia (6.3%), thrombocytopenia (5.1%), and jaundice (2.2%). The overall sustained virological response rates were 94.4% and 97.7% in the intention-to-treat and per-protocol analyses, respectively. Conclusions: the glecaprevir/pibrentasvir treatment regimen was highly effective and well tolerated among patients with compensated cirrhosis in the real-world setting.

Cellular senescence in liver fibrosis: Implications for age-related chronic liver diseases

INTRODUCTION

New insights indicate a causative link between cellular senescence and liver fibrosis. Senescent hepatic stellate cells (HSCs) facilitate fibrosis resolution, while senescence in hepatocytes and cholangiocytes acts as a potent mechanism driving liver fibrogenesis. In many clinical studies, telomeres and mitochondrial DNA contents, which are both aging biomarkers, were reportedly associated with a degree of liver fibrosis in patients with chronic liver diseases (CLDs); this highlights their potential as biomarkers for liver fibrogenesis. A deeper understanding of mechanisms underlying multi-step progression of senescence may yield new therapeutic strategies for age-related chronic liver pathologies.

AREAS COVERED

This review examines the recent findings from preclinical and clinical studies on mechanisms of senescence in liver fibrogenesis and its involvement in liver fibrosis. A comprehensive literature search in electronic databases consisting of PubMed and Scopus from inception to 31 August 2021 was performed.

EXPERT OPINION

Cellular senescence has diagnostic, prognostic, and therapeutic potential in progressive liver complications, especially liver fibrosis. Stimulating or reinforcing the immune response against senescent cells may be a promising and forthright biotherapeutic strategy. This approach will need a deeper understanding of the immune system's ability to eliminate senescent cells and the molecular and cellular mechanisms underlying this process.

Strategy for the Micro-Elimination of Hepatitis C among Patients with Diabetes Mellitus-A Hospital-Based Experience

Hepatitis C virus (HCV) infection can induce insulin resistance, and patients with diabetes mellitus (DM) have a higher prevalence of HCV infection. Patient outcomes improve after HCV eradication in DM patients. However, HCV micro-elimination targeting this population has not been approached. Little is known about using electronic alert systems for HCV screening among patients with DM in a hospital-based setting. We implemented an electronic reminder system for HCV antibody screening and RNA testing in outpatient departments among patients with DM. The screening rates and treatment rates at different departments before and after system implementation were compared. The results indicated that the total HCV screening rate increased from 49.3% (9505/19,272) to 78.2% (15,073/19,272), and the HCV-RNA testing rate increased from 73.4% to 94.2%. The anti-HCV antibody seropositive rate was 5.7%, and the HCV viremia rate was 62.7% in our patient population. The rate of positive anti-HCV antibodies and HCV viremia increased with patient age. This study demonstrates the feasibility and usefulness of an electronic alert system for HCV screening and treatment among DM patients in a hospital-based setting.

Retrieval of lost patients in the system for hepatitis C microelimination: a single-center retrospective study

Background

Hepatitis C virus (HCV) is one of the major causes of chronic liver disease, cirrhosis, and liver cancer. Most of the infected people have no clinical symptoms. The current strategy for HCV elimination includes test and treatment. In this study, we aimed to evaluate the campaign for retrieving patients who were lost to follow-up, for subsequent re-evaluation.

Methods

From January 2020 to October 2020, patients who had prior tests for positive anti-HCV antibody in 2010–2018 in our hospital were enrolled for our patient callback campaign. Patients who had unknown HCV RNA status or no documented successful antiviral therapy history were selected for anti-HCV therapy re-evaluation. To facilitate patient referral in the hospital, we developed an electronic reminding system and called the candidate patients via telephone during the study period.

Results

Through the hospital electronic system, 3783 patients with positive anti-HCV antibody documentation were identified. Among them, 1446 (38.22%) had tested negative for HCV RNA or had anti-HCV therapy, thereby excluded. Of the 2337 eligible patients, 1472 (62.99%) were successfully contacted and called back during the study period for subsequent HCV RNA testing and therapy. We found that 42.19% of the patients had positive HCV RNA and 88% received subsequent anti-HCV therapy.

Conclusions

A significant number of patients with positive HCV serology were lost for HCV confirmatory test or therapy in the hospital. Therefore, this targeted HCV callback approach in the hospital is feasible and effective in achieving microelimination.

Direct-acting antiviral treatment for Hepatitis C Virus in geriatric patients: a real-world retrospective comparison between early and late elderly patients

Introduction

Chronic hepatitis C virus (HCV) infection rates are high in the geriatric population considering that interferon-based therapy is usually intolerable. With the introduction of oral antiviral therapy for HCV, increased treatment tolerability and good treatment responses have been observed. However, treatment data regarding the geriatric population have been limited. Therefore, this retrospective study aimed to evaluate the efficacy and safety of direct-acting antiviral therapy for HCV in the geriatric population.

Materials and Methods

The primary end point was sustained virologic response (SVR) 12 weeks after treatment completion, whereas the secondary end points were treatment-related side effects and short-term survival rate following treatment.

Results

In total, 492 patients (median age, 73 years; 43.9% males), including 278 early elderly patients, were enrolled. Among the included patients, 45% had cirrhosis. HCV genotypes 1 (72.4%) and 2 (25.4%) were the most common. The overall SVR rate was 96.7%, with no difference in SVR rates observed between early and late elderly groups (96.8% vs. 96.7%; p = 0.983). Both groups showed similar side effects, including dizziness (11.4%), and fatigue (8.7%), with three patients discontinuing therapy owing to side effects. Both groups had a similar 3-year survival rate. Significant factors associated with post-treatment survival included cirrhosis, albumin, and creatinine level.

Conclusions

Our real-world data showed that both early and late elderly patients could undergo direct-acting antiviral treatment for HCV with excellent treatment outcomes.

The Oncogenic Role of Hepatitis C Virus

Persistent infection with hepatitis C virus (HCV) is a major risk factor for hepatocellular carcinoma (HCC). Accumulating evidence suggests that not only inflammation and subsequent fibrosis but also HCV itself are associated with hepatocarcinogenesis. To date, studies using transgenic mouse and cell-culture models, in which HCV proteins are expressed, indicate the direct pathogenicity of HCV, including oncogenic activity. In particular, the core protein of HCV induces excessive oxidative stress by impairing the mitochondrial electron transfer system by disrupting the function of the molecular chaperone, prohibitin. HCV also modulates intracellular signaling pathways, including mitogen-activated protein kinase, promoting the proliferation of hepatocytes. In addition, HCV induces disorders in lipid and glucose metabolism, thereby accelerating the progression of liver fibrosis and the development of HCC. Due to the development of direct-acting antivirals, which was made possible by basic research, HCV can be eradicated from almost all infected patients. However, such patients can develop HCC long after eradication of HCV, suggesting the genetic and/or epigenetic changes induced by HCV may be persistent. These results enhance our understanding of the role of HCV in hepatocarcinogenesis and will facilitate the development of therapeutic and preventive strategies for HCV-induced HCC.

Glecaprevir-pibrentasvir for chronic hepatitis C: Comparing treatment effect in patients with and without end-stage renal disease in a real-world setting

Introduction

Chronic hepatitis C virus (HCV) infection is increasingly observed in patients with renal disease. With the introduction of glecaprevir/pibrentasvir (GLE/PIB) as a pan-genotype therapy for HCV, treatment efficacy is expected to rise.

Materials and methods

This retrospective study evaluated the efficacy and safety of GLE/PIB treatment in adults with HCV infection and end-stage renal disease (ESRD). The primary end point was sustained virological response (SVR) observed 12 weeks after completed treatment.

Results

We enrolled 235 patients, including 44 patients with ESRD. Median age was 60 years, and 48% were males. Twenty-two percent had cirrhosis. HCV genotypes 1 (43%) and 2 (41%) were the most common. The overall SVR rate was 96.6%. Patients with ESRD were older than those without (67.6 years vs 58.3 years, p < 0.001) and trended toward having a higher prevalence of cirrhosis (32% vs 19%, p = 0.071). A significant proportion of patients with ESRD complained of skin itching during treatment (61% vs 26%, p < 0.001), and the SVR rate were similar between these two groups (95.45% vs 96.86%, p = 0.644).

Conclusions

Despite a higher rate of pruritus among patients with ESRD, GLE/PIB-based therapy achieved similarly high SVR rates among patients with and without ESRD.

Organic small molecule for detection and photodegradation of mitochondrial DNA mutations

A detection and degradation platform was developed to optically quantify the 6-enolate, 8-keto-dG, an important tautomer of mitochondrial mutated DNA 8-oxo-dG. We first found that 6-enolate, 8-keto-dG offers particular fluorescence emission under the conditions between pH ∼ 7 and ∼11. Thus, a mitochondria-targeting photosensitizer NV-12P was prepared to offer simultaneously photoinduced electron transfer and fluorescence resonance energy transfer (FRET) with 6-enolate, 8-keto-dG. Furthermore, NV-12P can also generate a reactive oxygen species to degrade 6-enolate, 8-keto-dG under irradiation conditions. This is the first publication about optical characterization, concentration detection and photodegradation of 6-enolate, 8-keto-dG, either in biological or in vitro applications.

Oxidative stress response in the pathogenesis of dengue virus virulence, disease prognosis and therapeutics: an update

Dengue virus (DENV) is a mosquito-borne arbovirus that causes febrile illness and can lead to a potentially lethal disease. The mechanism of disease pathogenesis is not completely understood, and there are currently no vaccines or therapeutic drugs available to protect against all four serotypes of DENV. Although many reasons have been suggested for the development of the disease, dengue studies have shown that, during DENV infection, there is an imbalance between oxidants and antioxidants that disrupts homeostasis. An increase in reactive oxygen species (ROS) levels triggers the sudden release of cytokines, which can lead to plasma leakage and other severe symptoms. In the present review, we give an overview of the oxidative stress response and its effect on the progression of dengue disease. We also discuss the role of oxidative-stress-associated molecules in disease prognostic and therapeutics.

Mitochondria in the biology, pathogenesis, and treatment of hepatitis virus infections

Hepatitis virus infections affect a large proportion of the global population. The host responds rapidly to viral infection by orchestrating a variety of cellular machineries, in particular, the mitochondrial compartment. Mitochondria actively regulate viral infections through modulation of the cellular innate immunity and reprogramming of metabolism. In turn, hepatitis viruses are able to modulate the morphodynamics and functions of mitochondria, but the mode of actions are distinct with respect to different types of hepatitis viruses. The resulting mutual interactions between viruses and mitochondria partially explain the clinical presentation of viral hepatitis, influence the response to antiviral treatment, and offer rational avenues for novel therapy. In this review, we aim to consider in depth the multifaceted interactions of mitochondria with hepatitis virus infections and emphasize the implications for understanding pathogenesis and advancing therapeutic development.

Association between mitochondrial DNA content and baseline serum levels of HBsAg in chronic hepatitis B infection

Recent studies have demonstrated a potential link between mitochondrial DNA (mtDNA) content and cirrhosis or hepatocellular carcinoma (HCC). However, there are few studies evaluating mtDNA content as a noninvasive marker of chronic hepatitis B infection (CHB). In this study, we conducted a case-control study to determine mtDNA content in peripheral blood leukocyte (PBL) samples from 76 CHB cases naïve to antivirus therapy and 96 healthy controls, and then evaluated the association between mtDNA content and baseline serum concentration of HBV markers. Consequently, CHB cases had significantly higher mtDNA content than healthy controls (1052.85 vs 618.98, P < 0.001). Pearson's correlation analysis revealed that mtDNA content was negatively correlated with the baseline levels of hepatitis B surface antigen (HBsAg) (r = -0.291, P = 0.011) in CHB patients. In a trend analysis, a statistically significant association was detected between lower mtDNA content and increasing levels of HBsAg (P = 0.015). In conclusion, our study provides the first epidemiological evidence that mtDNA content of CHB cases naive to antivirus therapy is significantly higher than healthy controls and the levels of mtDNA content is negatively associated with HBsAg. mtDNA content may serve as a potential noninvasive biomarker of CHB which may need more researches to validate.

Implications of oxidative stress on viral pathogenesis

Reactive species are frequently formed after viral infections. Antioxidant defences, including enzymatic and non-enzymatic components, protect against reactive species, but sometimes these defences are not completely adequate. An imbalance in the production of reactive species and the body's inability to detoxify these reactive species is referred to as oxidative stress. The aim of this review is to analyse the role of oxidative stress in the pathogenesis of viral infections and highlight some major therapeutic approaches that have gained importance, with regards to controlling virus-induced oxidative injury. Attention will be focused on DNA viruses (papillomaviruses, hepadnaviruses), RNA viruses (flaviviruses, orthomyxoviruses, paramyxoviruses, togaviruses) and retroviruses (human immunodeficiency virus). In general, viruses cause an imbalance in the cellular redox environment, which depending on the virus and the cell can result in different responses, e.g. cell signaling, antioxidant defences, reactive species, and other processes. Therefore, the modulation of reactive species production and oxidative stress potentially represents a novel pharmacological approach for reducing the consequences of viral pathogenesis.

Increased Mitochondrial Genetic Diversity in Persons Infected With Hepatitis C Virus

BACKGROUND & AIMS

The host genetic environment contributes significantly to the outcomes of hepatitis C virus (HCV) infection and therapy response, but little is known about any effects of HCV infection on the host beyond any changes related to adaptive immune responses. HCV persistence is associated strongly with mitochondrial dysfunction, with liver mitochondrial DNA (mtDNA) genetic diversity linked to disease progression.

METHODS

We evaluated the genetic diversity of 2 mtDNA genomic regions (hypervariable segments 1 and 2) obtained from sera of 116 persons using next-generation sequencing.

RESULTS

Results were as follows: (1) the average diversity among cases with seronegative acute HCV infection was 4.2 times higher than among uninfected controls; (2) the diversity level among cases with chronic HCV infection was 96.1 times higher than among uninfected controls; and (3) the diversity was 23.1 times higher among chronic than acute cases. In 2 patients who were followed up during combined interferon and ribavirin therapy, mtDNA nucleotide diversity decreased dramatically after the completion of therapy in both patients: by 100% in patient A after 54 days and by 70.51% in patient B after 76 days.

CONCLUSIONS

HCV infection strongly affects mtDNA genetic diversity. A rapid decrease in mtDNA genetic diversity observed after therapy-induced HCV clearance suggests that the effect is reversible, emphasizing dynamic genetic relationships between HCV and mitochondria. The level of mtDNA nucleotide diversity can be used to discriminate recent from past infections, which should facilitate the detection of recent transmission events and thus help identify modes of transmission.

Integrative Multi-omic Analysis of Human Platelet eQTLs Reveals Alternative Start Site in Mitofusin 2

Platelets play a central role in ischemic cardiovascular events. Cardiovascular disease (CVD) is a major cause of death worldwide. Numerous genome-wide association studies (GWASs) have identified loci associated with CVD risk. However, our understanding of how these variants contribute to disease is limited. Using data from the platelet RNA and expression 1 (PRAX1) study, we analyzed cis expression quantitative trait loci (eQTLs) in platelets from 154 normal human subjects. We confirmed these results in silico by performing allele-specific expression (ASE) analysis, which demonstrated that the allelic directionality of eQTLs and ASE patterns correlate significantly. Comparison of platelet eQTLs with data from the Genotype-Tissue Expression (GTEx) project revealed that a number of platelet eQTLs are platelet specific and that platelet eQTL peaks localize to the gene body at a higher rate than eQTLs from other tissues. Upon integration with data from previously published GWASs, we found that the trait-associated variant rs1474868 coincides with the eQTL peak for mitofusin 2 (MFN2). Additional experimental and computational analyses revealed that this eQTL is linked to an unannotated alternate MFN2 start site preferentially expressed in platelets. Integration of phenotype data from the PRAX1 study showed that MFN2 expression levels were significantly associated with platelet count. This study links the variant rs1474868 to a platelet-specific regulatory role for MFN2 and demonstrates the utility of integrating multi-omic data with eQTL analysis in disease-relevant tissues for interpreting GWAS results.

Significance of hepatitis virus infection in the oncogenic initiation of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most common causes of cancer-related death worldwide. Chronic infection of hepatitis B virus (HBV) and/or hepatitis C virus (HCV) is a major risk factor in the development of the HCC, independently from excessive alcohol abuse and metabolic disease. Since the biology of HBV and HCV is different, their oncogenic effect may go through different mechanisms, direct and/or indirect. Viral hepatitis infection is associated with cellular inflammation, oxidative stress, and DNA damage, that may lead to subsequent hepatic injuries such as chronic hepatitis, fibrosis, cirrhosis, and finally HCC. Direct oncogenic properties of these viruses are related with their genotypic characteristics and the ability of viral proteins to interact with host proteins, thus altering the molecular pathways balance of the cells. In addition, the integration of HBV DNA, especially the gene S and X, in a particular site of the host genome can disrupt chromosomal stability and may activate various oncogenic mechanisms, including those in hematopoietic cells. Recently, several studies also had demonstrated that viral hepatitis could trigger the population of hepatic cancer stem cells. This review summarize available pre-clinical and clinical data in literature regarding oncogenic properties of HBV and HCV in the early initiation of HCC.

Mitochondrial DNA Copy Number in Egyptian Patients with Hepatitis C Virus-Related Hepatocellular Carcinoma

AIM

To assess the use of mitochondrial DNA (mtDNA) content as a noninvasive molecular biomarker in hepatitis C virus-related hepatocellular carcinoma (HCV-HCC).

MATERIALS AND METHODS

A total of 135 participants were enrolled in the study. Equal numbers of subjects were enrolled in each of three clinically defined groups: those with HCV-related cirrhosis (HCV-cirrhosis), those with HCV-HCC, and a control group of age- and sex-matched healthy volunteers with no evidence of liver disease. mtDNA concentrations were determined using a quantitative real-time polymerase chain reaction (PCR) technique.

RESULTS

mtDNA content was lowest among the HCV-HCC cases. No statistically significant difference was observed between the group of HCV-cirrhosis and the control group as regards mtDNA level. HCC patients with multicentric hepatic lesions had significantly lower mtDNA content than HCC patients with less advanced disease. When a receiver operating characteristic curve analysis was used, a cutoff of 34 was assigned for mtDNA content to distinguish between HCV-HCC and HCV-cirrhosis patients who are not yet complicated by malignancy. Lower mtDNA content was associated with HCC risk when using either or both healthy controls and HCV-cirrhosis groups for reference.

CONCLUSIONS

mtDNA content analysis could serve as a noninvasive molecular biomarker that reflects tumor burden in HCV-HCC cases and could be used as a predictor of HCC risk in patients of HCV-cirrhosis. In addition, the nonsignificant difference of mtDNA level between HCV-cirrhosis patients and healthy controls could eliminate the gray zone created by the use of alpha-fetoprotein in some cirrhotic patients.

Mitochondrial DNAs decreased and correlated with clinical features in HCV patients from Yunnan, China

Hepatitis C was the most popular chronic infectious liver disease worldwide. It was identified that Hepatitis C virus (HCV) infection could lead to mitochondrial dysfunction, though the mechanism was not fully understood. To investigate whether mtDNA copy number could be affected by HCV infection and be associated with clinical features of HCV patients, mtDNA copy numbers were analyzed in 242 patients with HCV infection and 226 matched control samples. The results suggested that mtDNA copy numbers significantly decreased in HCV patients (68.80 ± 3.33) than in control samples (81.54 ± 4.50) (p = 0.022). When males/females were separated from total patients to compare mtDNA copy numbers with gender matched controls, mtDNA copy numbers still significantly decreased in male HCV patients (p = 0.002). Further analysis indicated that level of high-density lipoprotein cholesterol (HDL-C) was negatively correlated with mtDNA copy numbers in total HCV patients (r = -0.128, p = 0.047), and this correlation was more significant in male HCV patients (r = -0.266, p = 0.030). Intriguingly, aspartate amino-transferase (AST) showed positive correlation with mtDNA copy numbers (r = 0.260, p = 0.034) in male HCV patients. Our results indicated that mtDNA copy numbers depleted and correlated with clinical features in male HCV patients.

Circulating mitochondrial DNA content associated with the risk of liver cirrhosis: a nested case-control study

BACKGROUND AND AIMS

Accumulating evidence has indicated that variations of mitochondrial DNA (mtDNA) content may affect the susceptibility to hepatocellular carcinoma (HCC). However, no study has been conducted to evaluate the association of circulating mtDNA content and the risk of liver cirrhosis, a leading cause of HCC.

METHODS

We conducted a nested case-control study including 136 cirrhotic hepatitis B virus (HBV) cases and 136 frequency-matched non-cirrhotic HBV controls. We determined mtDNA content in serum DNA using quantitative real-time PCR and analyzed its association with cirrhosis risk.

RESULTS

We found that cirrhotic HBV patients had significantly lower levels of mtDNA content than non-cirrhotic HBV controls (P = 0.0184). Compared to patients with high mtDNA content, those with low mtDNA content had a 2.25-fold increased risk of cirrhosis [odds ratio (OR) 2.25, 95 % confidence interval (CI) 1.26-4.02]. This association exhibited a significant dose relationship as evidenced in both tertile and quartile analyses (P for trend = 0.0018 and 0.0008, respectively). Stratified analyses showed that the association was prominent in younger patients (P = 0.0122), males (P = 0.0069), never smokers (P = 0.0063), never drinkers (P = 0.0078), patients with a family history of HBV infection (P = 0.0062), and patients with low values of aspartate aminotransferase to platelet ratio index (APRI), a commonly used noninvasive marker for cirrhosis (P = 0.0109). Moreover, a joint effect was observed between low mtDNA content and high APRI values on cirrhosis risk (OR 24.07, 95 % CI 6.72-86.24).

CONCLUSIONS

Low circulating mtDNA content may confer an increased cirrhosis risk in HBV patients. Further prospective studies are warranted to validate these findings and explore the clinical significance.

Mitochondrial toxicity in human pregnancy: an update on clinical and experimental approaches in the last 10 years

Mitochondrial toxicity can be one of the most dreadful consequences of exposure to a wide range of external agents including pathogens, therapeutic agents, abuse drugs, toxic gases and other harmful chemical substances. However, little is known about the effects of mitochondrial toxicity on pregnant women exposed to these agents that may exert transplacental activity and condition fetal remodeling. It has been hypothesized that mitochondrial toxicity may be involved in some adverse obstetric outcomes. In the present study, we investigated the association between exposure to mitochondrial toxic agents and pathologic conditions ranging from fertility defects, detrimental fetal development and impaired newborn health due to intra-uterine exposure. We have reviewed data from studies in human subjects to propose mechanisms of mitochondrial toxicity that could be associated with the symptoms present in both exposed pregnant and fetal patients. Since some therapeutic interventions or accidental exposure cannot be avoided, further research is needed to gain insight into the molecular pathways leading to mitochondrial toxicity during pregnancy. The ultimate objective of these studies should be to reduce the mitochondrial toxicity of these agents and establish biomarkers for gestational monitoring of harmful effects.

Oxidative stress as a crucial factor in liver diseases

Redox state constitutes an important background of numerous liver disorders. The redox state participates in the course of inflammatory, metabolic and proliferative liver diseases. Reactive oxygen species (ROS) are primarily produced in the mitochondria and in the endoplasmic reticulum of hepatocytes via the cytochrome P450 enzymes. Under the proper conditions, cells are equipped with special molecular strategies that control the level of oxidative stress and maintain a balance between oxidant and antioxidant particles. Oxidative stress represents an imbalance between oxidant and antioxidant agents. Hepatocytic proteins, lipids and DNA are among the cellular structures that are primarily affected by ROS and reactive nitrogen species. The process results in structural and functional abnormalities in the liver. Thus, the phenomenon of oxidative stress should be investigated for several reasons. First, it may explain the pathogenesis of various liver disorders. Moreover, monitoring oxidative markers among hepatocytes offers the potential to diagnose the degree of liver damage and ultimately to observe the response to pharmacological therapies. The present report focuses on the role of oxidative stress in selected liver diseases.

RNA Viruses: ROS-Mediated Cell Death

Reactive oxygen species (ROS) are well known for being both beneficial and deleterious. The main thrust of this review is to investigate the role of ROS in ribonucleic acid (RNA) virus pathogenesis. Much evidences has accumulated over the past decade, suggesting that patients infected with RNA viruses are under chronic oxidative stress. Changes to the body's antioxidant defense system, in relation to SOD, ascorbic acid, selenium, carotenoids, and glutathione, have been reported in various tissues of RNA-virus infected patients. This review focuses on RNA viruses and retroviruses, giving particular attention to the human influenza virus, Hepatitis c virus (HCV), human immunodeficiency virus (HIV), and the aquatic Betanodavirus. Oxidative stress via RNA virus infections can contribute to several aspects of viral disease pathogenesis including apoptosis, loss of immune function, viral replication, inflammatory response, and loss of body weight. We focus on how ROS production is correlated with host cell death. Moreover, ROS may play an important role as a signal molecule in the regulation of viral replication and organelle function, potentially providing new insights in the prevention and treatment of RNA viruses and retrovirus infections.

Presence of cytomegalovirus DNA in leucocytes is associated with increased oxidative stress and subclinical atherosclerosis in healthy adults

OBJECTIVE

Investigate the latent cytomegalovirus (CMV) infection as a biomarker of oxidative stress and atherosclerosis.

METHODS

Latent CMV infection was diagnosed in healthy individuals with PCR-evidence of CMV DNA in peripheral leucocytes. Oxidative stress and atherosclerosis were measured by mitochondrial DNA oxidative damage index (mtDNA(ΔCT)) and intima media thickness (IMT).

RESULTS

The CMV DNA positive subjects had a higher mean mtDNA(ΔCT) and greater IMT than subjects in the control group.

CONCLUSIONS

Presence of CMV DNA in leucocytes, as a marker of latent CMV infection, was associated with increased levels of oxidative stress and subclinical atherosclerosis in healthy adults.

Mitochondrial dysfunctions and altered metals homeostasis: new weapons to counteract HCV-related oxidative stress

The hepatitis C virus (HCV) infection produces several pathological effects in host organism through a wide number of molecular/metabolic pathways. Today it is worldwide accepted that oxidative stress actively participates in HCV pathology, even if the antioxidant therapies adopted until now were scarcely effective. HCV causes oxidative stress by a variety of processes, such as activation of prooxidant enzymes, weakening of antioxidant defenses, organelle damage, and metals unbalance. A focal point, in HCV-related oxidative stress onset, is the mitochondrial failure. These organelles, known to be the "power plants" of cells, have a central role in energy production, metabolism, and metals homeostasis, mainly copper and iron. Furthermore, mitochondria are direct viral targets, because many HCV proteins associate with them. They are the main intracellular free radicals producers and targets. Mitochondrial dysfunctions play a key role in the metal imbalance. This event, today overlooked, is involved in oxidative stress exacerbation and may play a role in HCV life cycle. In this review, we summarize the role of mitochondria and metals in HCV-related oxidative stress, highlighting the need to consider their deregulation in the HCV-related liver damage and in the antiviral management of patients.

Oxidative stress and hepatitis C virus

The disproportionate imbalance between the systemic manifestation of reactive oxygen species and body’s ability to detoxify the reactive intermediates is referred to as oxidative stress. Several biological processes as well as infectious agents, physiological or environmental stress, and perturbed antioxidant response can promote oxidative stress. Oxidative stress usually happens when cells are exposed to more electrically charged reactive oxygen species (ROS) such as H2O2 or O2-. The cells’ ability to handle such pro-oxidant species is impeded by viral infections particularly within liver that plays an important role in metabolism and detoxification of harmful substances. During liver diseases (such as hepatocellular or cholestatic problems), the produced ROS are involved in transcriptional activation of a large number of cytokines and growth factors, and continued production of ROS and Reactive Nitrogen Species (RNS) feed into the vicious cycle. Many human viruses like HCV are evolved to manipulate this delicate pro- and antioxidant balance; thus generating the sustainable oxidative stress that not only causes hepatic damage but also stimulates the processes to reduce treatment of damage. In this review article, the oxidant and antioxidant pathways that are perturbed by HCV genes are discussed. In the first line of risk, the pathways of lipid metabolism present a clear danger in accumulation of viral induced ROS. Viral infection leads to decrease in cellular concentrations of glutathione (GSH) resulting in oxidation of important components of cells such as proteins, DNA and lipids as well as double strand breakage of DNA. These disorders have the tendency to lead the cells toward cirrhosis and hepatocellular carcinoma in adults due to constant insult. We have highlighted the importance of such pathways and revealed differences in the extent of oxidative stress caused by HCV infection.

Oxidative status and the response to pegylated-interferon alpha2a plus ribavirin in chronic genotype 4 HCV hepatitis

Oxidative stress may play a pathogenic role in chronic hepatitis C (CHC). The present study examined the oxidative status in plasma of patients with CHC who received pegylated interferon and ribavirin therapy. The following groups were included: (1) sustained virological response (28 patients), (2) null response (26 patients), (3) breakthrough (24 patients), (4) relapse (24 patients), (5) spontaneous cure (23 patients) and (6) twenty five normal subjects as a control group. Markers of oxidative stress including plasma malondialdehyde, nitric oxide, reduced glutathione, total antioxidant capacity and uric acid as well as serum ALT, AST, alkaline phosphatase, total bilirubin, albumin, prothrombin time were studied. The study indicated significant decline in reduced glutathione and total antioxidant capacity and markedly elevated levels of malondialdehyde and nitric oxide in all groups compared with the controls. Null response group had the highest levels of malondialdehyde and nitric oxide. Nitric oxide was significantly higher in those with null response compared with all other groups and with control subjects. Uric acid was significantly higher in spontaneous cure group compared with all other groups and with the controls. We concluded that CHC patients had increased oxidative stress. The oxidative status in plasma of these patients was not changed by antiviral therapy. The study also showed an important contribution of nitric oxide in null response patients. High serum uric acid did not interfere with the response and/or did not predict the response to antiviral therapy.