Risk factors for symptomatic mitochondrial toxicity in HIV/hepatitis C virus-coinfected patients during interferon plus ribavirin-based therapy

Mitochondrial DNA depletion in HIV-infected patients with chronic hepatitis C and effect of pegylated interferon plus ribavirin therapy

BACKGROUND

The metabolic stress derived from high levels of virus replication in both HIV and hepatitis C virus (HCV) infections results in mitochondrial DNA depletion, which seems to be enhanced in co-infected patients. The use of nucleoside analogues to treat HIV infection may further increase mtDNA depletion by inhibiting gamma DNA polymerase. Information on the impact of therapy with pegylated interferon (pegIFN) plus ribavirin on mtDNA is scarce and conflicting results have been reported.

PATIENTS AND METHODS

Fifty-nine HCV/HIV-co-infected patients (43 on and 16 off antiretroviral therapy) who initiated treatment with pegIFN plus ribavirin were retrospectively analysed. The amount of mtDNA in peripheral blood mononuclear cells (PBMC) was measured at baseline and at the end of HCV therapy.

RESULTS

Mean baseline serum HCV-RNA was 5.8 log IU/ml and 56% of patients were infected by HCV genotype 1. An inverse correlation between serum HCV-RNA levels and PBMC mtDNA content was recognized at baseline (r = -0.370; P = 0.006). HCV-RNA suppression at the end of HCV therapy was associated with a significant increase in mtDNA, particularly in patients with baseline HCV-RNA levels greater than 6 log IU/ml (+61 mtDNA copies/cell) and in subjects not taking antiretroviral therapy (+133 mtDNA copies/cell).

CONCLUSION

HCV replication correlates with the extent of mtDNA depletion in PBMC, and treatment of chronic hepatitis C is associated with a significant improvement in mtDNA content. This benefit, however, is not recognized when HCV medications are used along with antiretroviral therapy, probably because of a deleterious interaction of these drugs on mitochondria.

Predictive Value of Early Virologic Response in HIV/Hepatitis C Virus-Coinfected Patients Treated With an Interferon-Based Regimen Plus Ribavirin

BACKGROUND

As a result of adverse events, a moderate rate of virologic response, and high costs associated with hepatitis C virus (HCV) therapy, finding early markers of sustained treatment response is a clinical priority. In the HCV-monoinfected population, a reduction >or=2 log in plasma HCV RNA at week 12 of therapy (early virologic response [EVR]) predicts a sustained virologic response (SVR). Few data are available in HIV/HCV-coinfected patients, however.

METHODS

A subanalysis of data from HIV/HCV-coinfected patients treated with pegylated interferon-alpha-2b (PEG, 100-150 mug/wk) or interferon-alpha-2b (IFN, 3 MIU 3 times per week) plus ribavirin (RBV, 800-1200 mg/d) was conducted in a randomized single-center clinical trial. The duration of treatment was 48 weeks (only 24 weeks for HCV genotype 2 or 3 with a baseline HCV RNA level <800,000 IU/mL).

RESULTS

Ninety-five patients were randomized (43 assigned to IFN + RBV and 52 assigned to PEG + RBV). Eighty patients completed at least 12 weeks on therapy and were included in the EVR analysis. Thirty-five (43%) of them attained an SVR (56% and 30% of patients treated with PEG and IFN, respectively; P = 0.026). An EVR occurred in 55 (69%; 80% of PEG + RBV group and 56% of IFN + RBV group). Overall, 35 of 55 patients with an EVR were sustained responders, yielding a positive predictive value of 64% (70% in PEG + RBV arm and 55% in IFN + RBV arm). None of the patients who demonstrated an HCV RNA decline of <2 logs at week 12 reached an SVR (negative predictive value of 100%).

CONCLUSION

Our results confirm the utility of an EVR to predict the chance of the lack of an SVR in HIV/HCV-coinfected patients, particularly those treated with PEG.

Hepatitis C in HIV-positive patients--treatment and liver disease outcomes

Many human immunodeficiency virus (HIV) infected persons are coinfected with hepatitis C virus (HCV) and with the use of highly active antiretroviral therapy, liver disease from HCV has become an important cause of morbidity and mortality. The current guidelines recommend that human immunodeficiency virus and HCV coinfected patients be evaluated and treated for HCV if there are no major contraindications to treatment. Coinfected patients treated with pegylated interferon-a and ribavirin have sustained virologic responses (SVRs) of 27% to 40% which for a variety of reasons are lower than those reported in HCV mono-infected patients. Understanding that most patients will not achieve SVRs, strategies to evaluate for the role of maintenance interferon in delaying complications of liver disease are being evaluated. In patients who have failed prior treatment, cannot tolerate treatment, or who have contraindications to HCV treatment, the use of highly active antiretroviral therapy with careful monitoring for hepatotoxicity and aggressive counseling on alcohol and substance abuse may slow down fibrosis progression. As the data on liver transplantation in coinfected patients accumulate, patients with end stage liver disease should be referred early for evaluation in a transplant center. As new drugs for HCV are being developed, it will be of utmost importance to include coinfected patients earlier in the process on new drug trials and therapeutic strategies.

Alteration of cytochrome oxidase subunit I labeling is associated with severe mitochondriopathy in NRTI-related hepatotoxicity in HIV patients

Liver mitochondrial toxicity induced by nucleoside reverse transcriptase inhibitors (NRTI) in human immunodeficiency virus (HIV) patients has been associated with a wide range of liver involvement ranging from low-grade hepatotoxicity, asymptomatic lactacidemia to severe liver insufficiency, with massive steatosis and life-threatening lactic acidosis. Considerable efforts have been made in the last few years to establish clinical guidelines to avoid life-threatening NRTI-associated lactic acidosis. However, the important issue of low-grade NRTI-associated hepatotoxicity still needs to be unravelled since its natural history is largely unknown. We have recently reported a series of 13 monoinfected HIV patients with low-grade NRTI-associated toxicity. Our results outlined the heterogeneity of NRTI-induced hepatotoxicity and raised the question of its diagnosis. The present study evaluates the expression of cytochrome oxidase (COX) subunits I and IV, encoded by mitochondrial and nuclear DNA, respectively, in NRTI hepatotoxicity. The aim of our study was to compare the detection rate of mitochondrial abnormalities of immunohistochemistry for COX subunit I with electron microscopy. COX subunit I and IV labeling was performed together with light microscopy and ultrastructural analysis in a series of 55 liver biopsies from HIV monoinfected and HIV-hepatitis C virus coinfected patients. Clinical data were also recorded. Our major findings were: (i) decreased COX subunit I labeling is associated with severe ultrastructural mitochondrial alterations and may represent overt NRTI-induced mitochondrial cytopathy; (ii) mild ultrastructural damage associated with normal COX subunit I labeling is of unknown clinical significance. The results of the study suggest that COX subunit I labeling may be a valuable tool for the diagnosis of mitochondrial liver disease in HIV patients.

Antiretroviral medication considerations for individuals coinfected with HIV and hepatitis C virus

There is great need to treat HIV/hepatitis C virus (HCV)-coinfected individuals with both antiretroviral and anti-HCV pharmacotherapy. However, treatment for HIV may lead to hepatotoxicity, and there are potential interactions and synergistic effects between antiretrovirals and anti-HCV medications. The ideal antiretroviral therapy options for coinfected patients, in the setting of anti-HCV treatment, are unclear and present important challenges to clinicians. We review the current data on the use of antiretrovirals in HIV/HCV-coinfected patients and offer evidence-based recommendations on optimal selection and dosing of antiretroviral agents for this population.

Severe liver disease associated with prolonged exposure to antiretroviral drugs

BACKGROUND

Liver damage is frequently seen in HIV-positive subjects, often resulting from coinfection with hepatitis B and/or C viruses (HCV), alcohol abuse, etc. However, the etiology of liver disease still remains unknown for a small subset of individuals.

METHODS

Cryptogenic liver disease (CLD) was defined as persistently elevated aminotransferases levels in the absence of hepatitis C and/or B viruses replication and of other common causes of liver disease (alcohol, medications, etc). We identified cases initially meeting this definition by examining all HIV-positive subjects attended during the year 2004 in 2 large HIV clinics in Spain. Their clinical charts were retrospectively reviewed, and their assessment completed when needed to rule out other less frequent causes of liver disease. The stage of liver fibrosis was assessed by liver biopsy and/or elastography. To assess which factors could be associated with CLD, HIV-positive controls were chosen and matched by age, gender, and CD4 status.

RESULTS

CLD was diagnosed in 17 (0.5%) out of 3200 HIV-positive patients. Their mean age was 43 years, 82.4% were male, and 76% had acquired HIV through homosexual relationships. The mean time from HIV diagnosis was >15 years, and all patients had been exposed to antiretroviral therapy. Nevirapine, stavudine, and didanosine were the drugs more frequently used by this subset of patients. None of them had liver function test abnormalities before initiating antiretroviral therapy. Advanced liver fibrosis (F3-F4 Metavir scores) was recognized in 10 (58.8%) individuals, and 9 (52.9%) had developed symptomatic liver complications, including ascites (8), portal thrombosis (6), variceal bleeding (5), and encephalopathy (2). In the case-control analysis, prolonged didanosine exposure was the only independent predictor of developing CLD in this population.

CONCLUSIONS

CLD is an uncommon condition in HIV-positive individuals and might be associated with prolonged didanosine exposure. It may evolve causing severe liver complications, with variceal bleeding and portal thrombosis being particularly frequent.

Spontaneous hepatic decompensation in patients coinfected with HIV and hepatitis C virus during interferon-ribavirin combination treatment

Spontaneous hepatic decompensation was observed in 7 of 383 patients coinfected with human immunodeficiency virus (HIV) and hepatitis C virus (HCV) who were receiving treatment with interferon and ribavirin. Multivariate analysis identified the following risk factors: didanosine use (odds ratio [OR], 8.8; 95% confidence interval [CI], 1.2-102.3; P < .02), cirrhosis, (OR, 8.8; 95% CI, 1.2-104.2; P<.02), and elevated total bilirubin level (OR, 7.9; 95% CI, 1.08-93.3; P<.03). Didanosine should thus not be given to patients with cirrhosis, particularly when treatments for HCV and HIV infections have to be administered concomitantly.