Inosine triphosphatase polymorphisms and ribavirin pharmacokinetics as determinants of ribavirin-associate anemia in patients receiving standard anti-HCV treatment.

BACKGROUND: Functional variants of inosine triphosphatase (ITPA) were recently found to protect against ribavirin (RBV)-induced hemolytic anemia. However, no definitive data are yet available on the role of plasma RBV concentrations on hemoglobin (Hb) decrement. Moreover, no data have been published on the possible interplay between these 2 factors. METHODS: A retrospective analysis included 167 patients. The ITPA variants rs7270101 and rs1127354 were genotyped and tested using the χ test for association with Hb reduction at week 4. We also investigated, using multivariate logistic regression, the impact of RBV plasma exposure on Hb concentrations. RESULTS: Both single nucleotide polymorphisms were associated with Hb decrease. The carrier of at least 1 variant allele in the functional ITPA single nucleotide polymorphisms was associated with a lower decrement of Hb (-1.1 g/dL), as compared with patients without a variant allele (-2.75 g/dL; P = 4.09 × 10). RBV concentrations were not influenced by ITPA genotypes. A cut-off of 2.3 µg/mL of RBV was found to be associated with anemia (area-under-receiver operating characteristic = 0.630, sensitivity = 50.0%, and specificity = 69.5%, P = 0.008). In multivariate logistic regression analyses, the carrier of a variant allele (P = 0.005) and plasma RBV concentrations <2.3 µg/mL (P = 0.016) were independently associated with protection against clinically significant anemia at week 4. CONCLUSIONS: Although no direct relationship was found between ITPA polymorphisms and plasma RBV concentrations, both factors were shown to be significantly associated with anemia. A multivariate regression model based on ITPA genetic polymorphisms and RBV trough concentration was developed for predicting the risk of anemia. By relying upon these 2 variables, an individualized management of anemia seems to be feasible in recipients of pegylated interferon-RBV therapy.

Negative predictive value of IL28B, SLC28A2, and CYP27B1 SNPs and low RBV plasma exposure for therapeutic response to PEG/IFN-RBV treatment.

OBJECTIVES: The response rate to treatment of chronic hepatitis C virus-genotype 1 and 4 infections was recently found to be strongly influenced by many polymorphisms. The aim of our study was to carry out an integrated analysis of the effects of polymorphisms and ribavirin (RBV) plasma exposure on outcome. METHODS: The retrospective analysis included 174 patients. IL28B, CYP27B1, SLC29A1, SLC28A3, and SLC28A2 polymorphisms were genotyped and tested for association with sustained virological response. The impact of RBV plasma exposure during the first 3 months of therapy on outcome was also investigated. RESULTS: Considering patients infected by hepatitis C virus-1/4, 3 polymorphisms (IL28B rs8099917TT, CYP27B1 rs4646536TT, and CNT2 rs11854484TT) were associated with sustained virological response. The number of negative variant allele and low RBV exposure were correlated to percentage increasing to therapy failure, suggesting some degree of cumulative effect of the 4 factors. A cutoff of 2.5 µg/mL of RBV was found to be associated with outcome (area under ROC [AUROC] curve = 0.64, sensitivity = 55.0%, and specificity = 71.2%, P = 0.020). In multivariate logistic regression analyses, each variant allele and RBV plasma exposure cutoff were independently associated with outcome. CONCLUSIONS: In this study, we found that additional polymorphisms and RBV plasma exposure are also able to influence the achievement of response. Regardless of the magnitude of RBV pharmacokinetic exposure, the negative predictive value of the polymorphisms here investigated is much stronger than the positive one.

Experimental evaluation of a new system for laser tissue welding applied on damaged lungs.

OBJECTIVES: Alveolar air leaks represent a challenging problem in thoracic surgery, leading to increased patient morbidity and prolonged hospitalization. Several methods have been used, but no ideal technique exists yet. We investigated the lung-sealing capacity of an experimental kit for laser tissue welding. METHODS: The kit is composed of a semiconductor laser system applied on a protein substrate associated with a chromophore that increases absorption. In vitro tests on porcine lung tissue were done to define ideal laser parameters (power 100 Å, frequency 50 Hz, pulse duration 400 µs) and protein substrate dilution (50%). For in vivo tests, through a left thoracotomy, 14 pigs received two different lung damages: a linear incision and a circular incision. Protein substrate applied on damaged areas was treated with laser to obtain a layer that reconstituted the integrity of the visceral pleura. Air leaks were intraoperatively evaluated by water submersion test with an airway pressure of 20 cmH2O. Animals were sacrificed at postoperative days 0 and 7 to study early and late pathological features. RESULTS: After applying laser treatment, no air leaks were seen in all proofs except in 2 cases in which a second application was required. At time 0, pathological damage mostly consisted of superficial alveolar necrotic tissue covered by protein membrane. At time 7, a complete recovery of lung lesions by fibrous scar with slight inflammatory reaction of adjacent lung tissue was seen. CONCLUSIONS: This experimental study demonstrated the effectiveness of laser tissue welding applied to seal air leaks after lung surgery. Further studies are needed to verify acceptability for human application.