An index to predict ribavirin-induced anemia in asian patients with chronic genotype 1 hepatitis C

Inosine Triphosphate Pyrophosphatase (ITPase): Functions, Mutations, Polymorphisms and Its Impact on Cancer Therapies

Inosine triphosphate pyrophosphatase (ITPase) is an enzyme encoded by the ITPA gene and functions to prevent the incorporation of noncanonical purine nucleotides into DNA and RNA. Specifically, the ITPase catalyzed the hydrolysis of (deoxy) nucleoside triphosphates ((d) NTPs) into the corresponding nucleoside monophosphate with the concomitant release of pyrophosphate. Recently, thiopurine drug metabolites such as azathioprine have been included in the lists of ITPase substrates. Interestingly, inosine or xanthosine triphosphate (ITP/XTP) and their deoxy analogs, deoxy inosine or xanthosine triphosphate (dITP/dXTP), are products of important biological reactions such as deamination that take place within the cellular compartments. However, the incorporation of ITP/XTP, dITP/dXTP, or the genetic deficiency or polymorphism of the ITPA gene have been implicated in many human diseases, including infantile epileptic encephalopathy, early onset of tuberculosis, and the responsiveness of patients to cancer therapy. This review provides an up-to-date report on the ITPase enzyme, including information regarding its discovery, analysis, and cellular localization, its implication in human diseases including cancer, and its therapeutic potential, amongst others.

Liver fibrosis regression correlates with downregulation in liver angiogenesis in chronic hepatitis C through viral eradication

OBJECTIVES

The impact of viral eradication on hepatic angiogenesis is unknown. This study aimed to analyze the correlations of liver angiogenesis with liver fibrosis progression or regression in chronic hepatitis C (CHC) after viral eradication.

METHODS

From 2003 to 2020, a cohort of 130 eligible participants underwent paired percutaneous liver biopsies (median = 48 months apart; range = 46-62) at the treatment baseline and after sustained virological response to CHC treatment at the tertiary referral center. The collagen proportionate area (CPA) of liver tissue sections was determined using picrosirius red staining through digital image analysis. CD34 and α-smooth muscle actin (α-SMA) phenotypically quantitated liver angiogenesis and myofibroblasts, respectively, through immunohistochemistry staining, to correlate the total, portal, and extraportal liver angiogenesis with fibrogenesis.

RESULTS

Paired histology manifested significant regressions in fibrosis stages, and necroinflammatory grades (both P  < 0.001). The median of changes in CPAs (follow-up minus baseline) was -6.12% (interquartile range = -12.35 to -2.05%). The median of CPA changes per year was -1.38%/year (interquartile range = -2.98 to -0.51%/year). The significance of declines in total CD34 [coefficient (95% confidence interval), 5.577 (3.286-7.868); P  < 0.001] outweighed α-SMA declines, when explaining (R2 = 0.522; adjusted R2 = 0.502) the CPA declines through multiple regression analysis adjusting for other histological variables.

CONCLUSION

Through viral eradication in CHC, the downregulated liver angiogenesis significantly explains the CPA regression.

Performance of Acoustic Radiation Force Impulse Elastography for Staging Liver Fibrosis in Patients With Chronic Hepatitis C After Viral Eradication

BACKGROUND

Data on noninvasive liver fibrosis staging after viral eradication are unclear. This histology-based study validated the performance of liver stiffness (LS) measurements after viral eradication.

METHODS

Consecutive participants with chronic hepatitis C (CHC) who received concomitant LS measurements through acoustic radiation force impulse (ARFI) elastography and percutaneous liver biopsy were prospectively screened and analyzed.

RESULTS

Of the 644 patients, 521 (80.9%) underwent a biopsy at treatment baseline, and the remaining 123 (19.1%) underwent a biopsy at 3 years (median; interquartile range, 0.1) after the sustained virological response (SVR) to pegylated interferon-based and direct-acting antiviral treatments. The proportions of histological fibrosis stages did not differ significantly between the pretreatment and post-SVR groups (P = .0615). However, the LS values differed significantly (P < .0001). The median LS values (presented as shear wave velocities in meters per second) were 1.51 (0.92) for the pretreatment group and 1.22 (0.77) for the post-SVR group. The cutoffs (areas under the receiver operating characteristic curve, obtained using the bootstrap method) to dichotomize between METAVIR fibrosis stage F1 versus stages F2-F4, F1-F2 versus F3-F4, and F1-F3 versus F4 were 1.47 (0.8333, 95% confidence interval [CI] 0.7981-0.8663), 1.81 (0.8763, 95% CI 0.8376-0.9107), and 1.86 (0.8811, 95% CI 0.8378-0.9179) in the pretreatment group, respectively, and 1.22 (0.7872, 95% CI 0.7001-0.8624), 1.59 (0.8808, 95% CI 0.8034-0.9422), and 1.75 (0.9018, 95% CI 0.8201-0.9644) in the post-SVR group, respectively.

CONCLUSIONS

The performance of LS measurements through ARFI elastography is promising to determine the liver fibrosis stage on necroinflammation-resolved histology in CHC after viral eradication.

A facile PCR-RFLP method for genotyping of ITPA rs1127354 and rs7270101 polymorphisms

BACKGROUND

Inosine triphosphate pyrophosphatase (ITPA) gene single nucleotide polymorphisms (SNPs), rs1127354 and rs7270101, may cause a functional impairment in ITPase enzyme, resulting anemia protection in patients with chronic hepatitis C virus (HCV) infection undergoing ribavirin (RBV)-dependent regimens. The main purpose of this study was to provide and validate a simple, rapid, and inexpensive polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technique for genotyping of ITPA rs1127354 and rs7270101 polymorphisms in chronic HCV-infected patients.

METHODS

In the current study, 100 Iranian patients with chronic hepatitis C were examined and genotyped for ITPA rs1127354 and rs7270101 gene polymorphisms. To genotype rs1127354 and rs7270101 polymorphisms, PCR-RFLP technique and sequencing technique were performed on these samples. To validate the PCR-RFLP method, the PCR-RFLP genotyping results should be 100% concordant with the PCR-sequencing results.

RESULTS

The rs1127354 and rs7270101 polymorphisms of ITPA gene were genotyped by PCR-RFLP technique and sequencing simultaneously, and the results of both techniques were 100% concordant in all 100 patients. Both PCR-RFLP and sequencing techniques indicated that the genotypic frequency of rs7270101 was 80% AA, 19% AC and 1% CC, and for rs1127354 was 79% CC, 20% CA and 1% AA, respectively.

CONCLUSION

We developed and validated a rapid and inexpensive PCR-RFLP technique for the detection of ITPA rs1127354 and rs7270101 gene polymorphisms.

Changes in liver stiffness measurement using acoustic radiation force impulse elastography after antiviral therapy in patients with chronic hepatitis C

Background

To compare on-treatment and off-treatment parameters acquired using acoustic radiation force impulse elastography, the Fibrosis-4 (FIB-4) index, and aspartate aminotransferase-to-platelet ratio index (APRI) in patients with chronic hepatitis C (CHC).

Methods

Patients received therapies based on pegylated interferon or direct-acting antiviral agents. The changes in paired patient parameters, including liver stiffness (LS) values, the FIB-4 index, and APRI, from baseline to sustained virologic response (SVR) visit (24 weeks after the end of treatment) were compared. Multiple regression models were used to identify significant factors that explained the correlations with LS, FIB-4, and APRI values and SVR.

Results

A total of 256 patients were included, of which 219 (85.5%) achieved SVR. The paired LS values declined significantly from baseline to SVR visit in all groups and subgroups except the nonresponder subgroup (n = 10). Body mass index (P = 0.0062) and baseline LS (P < 0.0001) were identified as independent factors that explained the LS declines. Likewise, the baseline FIB-4 (P < 0.0001) and APRI (P < 0.0001) values independently explained the declines in the FIB-4 index and APRI, respectively. Moreover, interleukin-28B polymorphisms, baseline LS, and rapid virologic response were identified as independent correlates with SVR.

Conclusions

Paired LS measurements in patients treated for CHC exhibited significant declines comparable to those in FIB-4 and APRI values. These declines may have correlated with the resolution of necroinflammation. Baseline LS values predicted SVR.

A Comprehensive Index for Predicting Risk of Anemia from Patients' Diagnoses

This article demonstrates how time-dependent, interacting, and repeating risk factors can be used to create more accurate predictive medicine. In particular, we show how emergence of anemia can be predicted from medical history within electronic health records. We used the Veterans Affairs Informatics and Computing Infrastructure database to examine a retrospective cohort of 9,738,838 veterans over an 11-year period. Using International Clinical Diagnoses Version 9 codes organized into 25 major diagnostic categories, we measured progression of disease by examining changes in risk over time, interactions in risk of combination of diseases, and elevated risk associated with repeated hospitalization for the same diagnostic category. The maximum risk associated with each diagnostic category was used to predict anemia. The accuracy of the model was assessed using a validation cohort. Age and several diagnostic categories significantly contributed to the prediction of anemia. The largest contributors were health status ([Formula: see text] = -1075, t = -92, p < 0.000), diseases of the endocrine ([Formula: see text] = -1046, t = -87, p < 0.000), hepatobiliary ([Formula: see text] = -1043, t = -72, p < 0.000), kidney ([Formula: see text] = -1125, t = -111, p < 0.000), and respiratory systems ([Formula: see text] = -1151, t = -89, p < 0.000). The AUC for the additive model was 0.751 (confidence interval 74.95%-75.26%). The magnitude of AUC suggests that the model may assist clinicians in determining which patients are likely to develop anemia. The procedures used for examining changes in risk factors over time may also be helpful in other predictive medicine projects.

A disease spectrum for ITPA variation: advances in biochemical and clinical research

Human ITPase (encoded by the ITPA gene) is a protective enzyme which acts to exclude noncanonical (deoxy)nucleoside triphosphates ((d)NTPs) such as (deoxy)inosine 5′-triphosphate ((d)ITP), from (d)NTP pools. Until the last few years, the importance of ITPase in human health and disease has been enigmatic. In 2009, an article was published demonstrating that ITPase deficiency in mice is lethal. All homozygous null offspring died before weaning as a result of cardiomyopathy due to a defect in the maintenance of quality ATP pools. More recently, a whole exome sequencing project revealed that very rare, severe human ITPA mutation results in early infantile encephalopathy and death. It has been estimated that nearly one third of the human population has an ITPA status which is associated with decreased ITPase activity. ITPA status has been linked to altered outcomes for patients undergoing thiopurine or ribavirin therapy. Thiopurine therapy can be toxic for patients with ITPA polymorphism, however, ITPA polymorphism is associated with improved outcomes for patients undergoing ribavirin treatment. ITPA polymorphism has also been linked to early-onset tuberculosis susceptibility. These data suggest a spectrum of ITPA-related disease exists in human populations. Potentially, ITPA status may affect a large number of patient outcomes, suggesting that modulation of ITPase activity is an important emerging avenue for reducing the number of negative outcomes for ITPA-related disease. Recent biochemical studies have aimed to provide rationale for clinical observations, better understand substrate selectivity and provide a platform for modulation of ITPase activity.

The ITPA and C20orf194 Polymorphisms and Hematological Changes During Treatment With Pegylated-Interferon Plus Ribavirin in Patients With Chronic Hepatitis C

BACKGROUND

It has been found that ITPase deficiency is caused by ITPA gene polymorphisms. It was observed that ITPA polymorphisms have impact on hematological changes, including hemoglobin (Hb)-decline during treatment of chronic hepatitis C (CHC) patients with pegylated-interferon (PEG-IFN) plus ribavirin (RBV).

OBJECTIVES

This study aimed to assess the effect of ITPA and C20orf194 polymorphisms on hematological changes at week 4 of treatment with PEG-IFN plus RBV in patients with CHC.

PATIENTS AND METHODS

In this retrospective study, 168 patients with CHC (56% HCV genotype-1 and 44% HCV genotype-3) under the treatment of PEG-IFN plus RBV were genotyped for rs1127354, rs7270101 and rs6051702 polymorphisms by the polymerase chain reaction-restriction fragment length polymorphism. Hematological changes including Hb-, platelet (Plt)- and white blood cell-decline at week 4 of the treatment were assessed.

RESULTS

In univariate analysis, rs1127354 and HCV genotypes were found to influence the Hb-decline at week 4 of the treatment. In multivariate analysis, rs1127354 CA + AA and HCV genotype-3 were found to have a great role on prevention of Hb-decline. Furthermore, rs1127354 and HCV RNA levels were found to influence the Plt-decline at week 4 of the treatment in the univariate analysis. In multivariate analysis, rs1127354 CA + AA and HCV RNA levels less than 600,000 IU/mL were found to be associated with a higher level of Plt-decline.

CONCLUSIONS

In patients with CHC, who were treated with PEG-IFN plus RBV, Hb-decline was affected by rs1127354 and HCV genotypes. However, Plt-decline may be altered by rs1127354 and baseline HCV RNA levels.