Critical review of the use of erythropoietin in the treatment of anaemia during therapy for chronic hepatitis C

Prevalence and Clinical Correlates of Chronic Hepatitis E Infection in German Renal Transplant Recipients With Elevated Liver Enzymes

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Background

Elevated liver enzymes are frequently observed in renal transplant recipients and warrant further exploration. In immunosuppressed patients, hepatitis E virus (HEV) infection may cause chronic hepatitis, cirrhosis, and extrahepatic manifestations such as renal injury.

Methods

We performed a retrospective cross-sectional study investigating the prevalence, clinical correlates, and outcome of chronic HEV infection in a cohort of renal transplant recipients with elevated liver enzymes.

Results

Over a period of 30 months, 140 of 1469 renal transplant recipients had elevated liver enzymes, of which serum samples from 98 patients were available to determine HEV status. Seventeen patients were detected with HEV infection, of which 16 developed chronic HEV infection, while 1 patient controlled viremia (prevalence of chronic infection of 16.3%, with a minimum prevalence of 1.1% in the whole cohort). Increased liver stiffness was indicated by an average FibroScan result of 11.2 kPa in these patients. All 16 patients with chronic HEV infection were treated with ribavirin for a mean duration of 3 months. Five patients developed a viral rebound and received a second treatment course, of which 2 controlled HEV replication. Six months after the end of therapy, HEV clearance was achieved in 81.3% of the patients. One patient developed ribavirin resistance. Hemolytic anemia after ribavirin treatment was frequent, requiring blood transfusion in 3 patients. Four patients developed de novo glomerulonephritis, of which 2 were possibly associated with HEV infection.

Conclusions

This retrospective study showed that prevalence of chronic HEV infection was high in our renal transplant patient cohort and was associated with significant liver impairment and the occurrence of renal injury. Ribavirin treatment was effective and should be initiated early to avoid complications, but the risk of severe hemolytic anemia makes strict monitoring essential.

ITPase activity modulates the severity of anaemia in HCV-related cirrhosis treated with ribavirin-containing interferon-free regimens

BACKGROUND

To investigate the association between inosine triphosphatase (ITPase) activity and the degree of anaemia occurring during direct-acting antiviral (DAA)/ribavirin (RBV)-based therapy in patients with cirrhosis.

METHODS

In a multicentre, prospective study 227 patients with HCV-related cirrhosis treated with DAA and RBV were enrolled. All patients were screened for the rs1127354 and rs7270101 ITPA single nucleotide polymorphisms using direct sequencing.

RESULTS

150 (66.1%) patients had normal (100%) ITPase activity, 48 (21.1%) had moderate (60%) activity and 29 (12.8%) minimal (≤30%) activity. The ITPase activity significantly influenced the haemoglobin concentration: at day 15 it was -1.248 (sd ±0.978) in the 150 patients with an ITPase activity of 100% and -0.616 (±0.862) in the 77 patients with an ITPase activity less than 100% (P<0.000), and at day 30 it was -1.941 ±1.218 versus -1.11 ±1.218 (P<0.000). The 63 patients with a severe (at least 3/dl) haemoglobin decline, compared to those without, more frequently had an ITPase activity of 100% (82.1% versus 62.8%; P=0.021), were older (mean age ±sd: 66.7 ±8.2 versus 61.4 ±9.7 years; P=0.004) and were treated with a higher ribavirin dose (13.7 ±2.1 versus 12.8 ±2.5 mg/kg/day; P=0.008). At multivariate logistic regression analysis, the ITPase activity of 100% (OR: 2.83; 95% CI: 1.12, 7.10), male gender (OR: 3.22; 95% CI: 1.35, 7.66), body mass index (OR: 1.17; 95% CI: 1.03, 1.34) and dose of ribavirin (OR: 1.22; 95% CI: 1.06, 1.47) were independent predictors of a severe decline in haemoglobin (P<0.0001).

CONCLUSIONS

This study suggests that the polymorphisms in the ITPA gene influence the severity of anaemia during the first month of a DAA/RBV-based treatment in HCV-related cirrhosis.

AG490 suppresses EPO-mediated activation of JAK2-STAT but enhances blood flow recovery in rats with critical limb ischemia

Background

Erythropoietin (EPO) has been demonstrated to enhance recovery in ischemic organs through enhancing angiogenesis. In this study, we used an experimental critical limb ischemia (CLI) rat model to reveal the underlying mechanisms and directly examine the benefits of the anti-apoptotic capacity of EPO in the acute phase of limb ischemia and following blood flow recovery.

Methods

To determine the role of the JAK2/STAT pathway in EPO-enhanced recovery after CLI, male Sprague-Dawley rats (n = 8 for each group) were divided into group 1 (normal control), group 2 (CLI treated with normal saline), group 3 (CLI treated with EPO), group 4 (CLI treated with AG490, a JAK2 inhibitor), and group 5 (CLI treated with EPO and AG490). Animals were sacrificed either at day 1 or day 14 and biochemical and histopathological examination of ischemic quadriceps were conducted.

Results

At day 1, EPO administration reduced expression levels of apoptotic indices and activated the JAK2/STAT pathway; this activation was inhibited by additional AG490 treatment. Furthermore, the decrease in the size of the infarcted area, as well as activation of ERK1/2 and JNK showed similar regulatory trends with EPO or AG490 treatment. Of Interest, EPO and AG490 in combination showed a synergistic effect, increasing expression levels of antioxidants (GR, GPx, NQO-1) and decreasing transcriptional levels of pro-inflammatory factors (TNF-α, NF-kB). At day 14, laser Doppler analysis showed that the blood flow recovery was enhanced by EPO, AG490, or combined treatment.

Conclusion

Although inhibition of the JAK2/STAT pathways reduces the anti-apoptotic effects of EPO in the early phase of CLI, the benefits of AG490 in anti-inflammation and anti-oxidation still play a positive role in enhancing blood flow recovery after CLI.

Ombitasvir/Paritaprevir/Ritonavir Plus Dasabuvir: A Review in Chronic HCV Genotype 1 Infection

A fixed-dose tablet comprising ombitasvir (an NS5A replication complex inhibitor), paritaprevir (an NS3/4A protease inhibitor) and ritonavir (a cytochrome P450 inhibitor) taken in combination with dasabuvir (an NS5B polymerase inhibitor) is indicated for the treatment of chronic hepatitis C virus (HCV) genotype 1 infection in several countries, including the USA (copackaged as Viekira Pak(™)) and those of the EU (Viekirax(®) and Exviera(®)). In phase II and III trials, this interferon-free regimen, taken ± ribavirin, provided high rates of sustained virological response 12 weeks post-treatment in adults with chronic HCV genotype 1a or 1b infection, including those with compensated cirrhosis, liver transplants or HIV-1 co-infection. The regimen was generally well tolerated, with nausea, insomnia, asthenia, pruritus, other skin reactions and fatigue being among the most common tolerability issues. Thus, ombitasvir/paritaprevir/ritonavir plus dasabuvir is an effective interferon-free, direct-acting antiviral regimen for use ± ribavirin in a broad range of adults chronically infected with HCV genotype 1.

VDR gene polymorphisms impact on anemia at 2 weeks of anti-HCV therapy: a possible mechanism for early RBV-induced anemia

OBJECTIVES

Vitamin D receptors (VDR) bind calcitriol and modulate several physiological systems through genomic and nongenomic pathways. Calcitriol stimulates store-operated channels Ca²⁺ influx by translocation of the caveolar VDR to the plasma membrane. Intracellular Ca²⁺ levels in erythrocytes control biophysical properties and an increase in its concentration can deregulate membrane composition, cell volume, glycolytic enzymes regulation, redox state, and cell clearance.We evaluated the role of single nucleotide polymorphisms in ITPA, CYP27B1, CYP24A1, and VDR genes in the prediction of ribavirin-induced anemia in HCV-1/2/3/4 patients at 2 and 4 weeks of treatment.

PATIENTS AND METHODS

Two hundred and twenty-five patients treated with ribavirin and pegylated interferon-α were genotyped by real-time PCR.

RESULTS

BMI at baseline more than 30 kg/m² [P=0.013, odds ratio (OR): 10.95, 95% confidence interval (CI): 1.66-74.21], alanine aminotransferase at baseline more than 37 IU/l (P=0.020, OR: 0.26, 95% CI: 0.09-0.81), and the VDR BsmI AA profile (P=0.003, OR: 5.09, 95% CI: 1.72-15.05) were anemia-predictive factors at 2 weeks of therapy. At week 4, the ITPA rs6051702 AC/CC profile (P=0.001, OR: 0.19, 95% CI: 0.07-0.51) was the only factor that could predict this side effect.

CONCLUSION

The BsmI AA genotype is a predictive factor of 2-week anemia and it could be related to a VDR-enhanced activity, and thus an increased calcium influx, resulting in the deregulation of the Ca²⁺-dependent signaling, which can lead to erythrocytes hemolysis. This rapid mechanism could be responsible for the development of early anemia.These results indicate for the first time the strong, significant, and independent role of VDR in the early development of ribavirin-induced anemia and confirm the ITPA function in the prediction of anemia at week 4.

Role of genetic polymorphisms in hepatitis C virus chronic infection

AIM: To analyze the host genetics factors influencing the clinical course and the response to antiviral treatment in patients with chronic hepatitis C (CHC).

METHODS: We conducted an electronic search on the PubMed and MEDLINE (2000-2014) databases and Cochrane library (2000-2014). A total of 73 articles were retrieved and their data were extensively evaluated and discussed by the authors and then analyzed in this review article.

RESULTS: Several studies associated polymorphisms in the interleukin 28B gene on chromosome 19 (19q13.13) with a spontaneous viral clearance in acute hepatitis C and with the response to pegylated interferon (Peg-IFN)-based treatment in chronic hepatitis C patients. Other investigations demonstrated that inosine triphosphate pyrophosphatase genetic variants protect hepatitis C virus-genotype-1 CHC patients from ribavirin-induced anemia, and other studies that a polymorphism in the patatin-like phospholipase domain-containing protein 3 was associated with hepatic steatosis in CHC patients. Although not conclusive, some investigations suggested that the vitamin D-associated polymorphisms play an important role in the achievement of sustained virologic response in CHC patients treated with Peg-IFN-based antiviral therapy. Several other polymorphisms have been investigated to ascertain their possible impact on the natural history and on the response to treatment in patients with CHC, but the data are preliminary and warrant confirmation.

CONCLUSION: Several genetic polymorphisms seem to influence the clinical course and the response to antiviral treatment in patients with CHC, suggesting individualized follow up and treatment strategies.

Mechanism of erythropoietin regulation by angiotensin II

Erythropoietin (EPO) is the primary regulator of red blood cell development. Although hypoxic regulation of EPO has been extensively studied, the mechanism(s) for basal regulation of EPO are not well understood. In vivo studies in healthy human volunteers and animal models indicated that angiotensin II (Ang II) and angiotensin converting enzyme inhibitors regulated blood EPO levels. In the current study, we found that Ang II induced EPO expression in situ in murine kidney slices and in 786-O kidney cells in culture as determined by reverse transcription polymerase chain reaction. We further investigated the signaling mechanism of Ang II regulation of EPO in 786-O cells. Pharmacological inhibitors of Ang II type 1 receptor (AT1R) and extracellular signal-regulated kinase 1/2 (ERK1/2) suppressed Ang II transcriptional activation of EPO. Inhibitors of AT2R or Src homology 2 domain-containing tyrosine phosphatase had no effect. Coimmunoprecipiation experiments demonstrated that p21Ras was constitutively bound to the AT1R; this association was increased by Ang II but was reduced by the AT1R inhibitor telmisartan. Transmembrane domain (TM) 2 of AT1R is important for G protein-dependent ERK1/2 activation, and mutant D74E in TM2 blocked Ang II activation of ERK1/2. Ang II signaling induced the nuclear translocation of the Egr-1 transcription factor, and overexpression of dominant-negative Egr-1 blocked EPO promoter activation by Ang II. These data identify a novel pathway for basal regulation of EPO via AT1R-mediated Egr-1 activation by p21Ras-mitogen-activated protein kinase/ERK kinase-ERK1/2. Our current data suggest that Ang II, in addition to regulating blood volume and pressure, may be a master regulator of erythropoiesis.

Inosine triphosphatase deficiency helps predict anaemia, anaemia management and response in chronic hepatitis C therapy

Anaemia frequently complicates peginterferon/ribavirin therapy for chronic hepatitis C infection. Better prediction of anaemia, ribavirin dose reduction or erythropoietin (EPO) need, may enhance patient management. Inosine triphosphatase (ITPA) genetic variants are associated with ribavirin-induced anaemia and dose reduction; however, their impact in real-life clinic patient cohorts remains to be defined. We studied 193 clinic patients with chronic hepatitis C infection of mixed viral genotype (genotype 1/4 n = 123, genotype 2/3, n = 70) treated with peginterferon/ribavirin. Patients were genotyped for ITPA polymorphisms rs1127354 and rs7270101 using Taqman primers. Hardy-Weinberg equilibrium was present. Estimated ITPA deficiency was graded on severity (0-3, no deficiency/mild/moderate/severe, n = 126/40/24/3, respectively). Multivariable models tested the association with anaemia at 4 weeks of treatment [including decline in haemoglobin (g/dL); haemoglobin <10 g/dL and haemoglobin decline >3 g/dL]; ribavirin dose reduction and EPO use and explored sustained viral response (SVR) to peginterferon/ribavirin. More severe ITPA deficiency was associated with less reduction in haemoglobin level (P <0.001; R(2) = 0.34), less ribavirin dose reduction (OR 0.42; (95% CI = 0.23-0.77); P = 0.005) and less EPO use [OR 0.53; (0.30-0.94); P = 0.029]. ITPA deficiency was associated with SVR [OR: 1.70; (1.02-2.83); P = 0.041] independently of clinical covariates (adjusted R(2) = 0.31). In this clinical cohort, ITPA deficiency helped predict the risk of on-treatment anaemia, ribavirin dose reduction, need for EPO support and was associated with SVR. For patients on HCV regimens including peginterferon/ribavirin, testing for ITPA deficiency may have clinical utility.

The association of cytopenias and weight loss with hepatitis C virus virologic response in HIV/HCV-coinfected patients treated with PEG-IFN and RBV

BACKGROUND

Pegylated interferon (PEG-IFN)/ribavirin (RBV)-related cytopenias have been associated with improved virological outcomes among hepatitis C virus (HCV)-monoinfected patients. This analysis evaluated PEG-IFN/RBV-related cytopenias with virological responses among HIV/HCV-coinfected patients.

METHODS

Pooled data from PARADIGM and AIDS Pegasys Ribavirin International CO-infection Trial (APRICOT) trials of HIV/HCV-infected patients treated with PEG-IFN/RBV. Virologic response was categorized as HCV RNA detectable (end of treatment nonresponders [ET-NR]) or nondetectable (end of treatment responders [ETR]). Declines in hemoglobin (Hgb), platelets, neutrophils, lymphocytes, and weight between the groups were compared via analysis of covariance and Cochran-Mantel-Haenszel test.

RESULTS

A total of 474 patients, 291 ET-NR and 183 ETR (67 relapsers, 116 with sustained virologic response), 81% male, 52% Caucasian, 88% noncirrhotic, and 67% nondetectable HIV. The ETR experienced greater Hgb declines (≥3.0 g/dL) from baseline (73.8% versus 55.0%; P < .0001), neutrophils ≤1 and ≤ 0.5 × 10(9)/L (66.1% versus 56.4%; P = .0334 and 42.6% versus 33.3%; P = .0312, respectively), and lymphocytes ≤1.5 and ≤0.5 × 10(9)/L (99.5% versus 87.6%; P < .0001 and 24.6% versus 14.9%; P =.0079, respectively).

CONCLUSIONS

The HIV/HCV-coinfected patients with ETR experienced greater declines in Hgb, neutrophils, and lymphocytes than the ET-NR patients.

Erythropoietin administration suppresses human monocyte function in vitro and during therapy-induced anemia in HCV patients

Erythropoietin (EPO) is a hormone that controls red blood cell production. Binding of EPO to the EPO-receptor results in increased numbers of red blood cells in the circulation, which makes EPO a potent molecule to treat anemia in various groups of patients. Although numerous studies have examined the clinical effects of EPO, its immunological effects have received less attention. In this study, we examined the immunological effects of EPO on human monocytes. We show that human monocytes express EPO receptor mRNA, and are responsive to EPO in cell culture. In vitro exposure of PBMC from individuals to EPO and the TLR4 ligand LPS showed a significant reduction of monocytes producing IL-6 and TNF, while the frequencies of IL-12p40, IL-10, MIP-1β and IL-8-producing cells did not change upon incubation with EPO. In addition, EPO did increase the phagocytic activity but did not affect the ability to produce ROS by monocytes. Moreover, we studied eight chronic HCV patients undergoing treatment with peg-IFN and ribavirin, who were administered EPO for treatment-induced anemia. Blood was collected before and 7 days after EPO injection. In 7 patients, we observed a significant decline at day 7 after EPO administration of the frequency of monocytes producing various pro-inflammatory cytokines following stimulation with the TLR4 ligand LPS and the TLR7/8 ligand R848, which is in line with our in vitro findings. Our findings demonstrate an inhibitory effect of EPO on the secretion of effector molecules by monocytes and a stimulatory effect on the phagocytic activity by monocytes.

The application and mechanism of action of ribavirin in therapy of hepatitis C

Ribavirin has been used as an antiviral agent for several decades. Although it has activity against numerous viruses, its major use clinically has been in the treatment of respiratory syncytial virus in paediatric patients and chronic HCV infection in both children and adults. This review highlights the clinical application and mechanism of action of ribavirin and discusses the future role of ribavirin in treatment of HCV where there are intense research efforts to improve therapy.