Antipyrine clearance and metabolite excretion in patients with chronic hepatitis C

Vibrational spectroscopic studies and DFT calculations of 4-aminoantipyrine

The pyrazole derivative, 4-aminoantipyrine (4AAP), used as an intermediate for the synthesis of pharmaceuticals especially antipyretic and analgesic drugs has been analyzed experimentally and theoretically for its vibrational frequencies. The FTIR and FT Raman spectra of the title compound have been compared with the theoretically computed frequencies invoking the standard 6-311g(d,p) and cc-pVDZ basis sets at DFT level of theory (B3LYP). The harmonic vibrational frequencies at B3LYP/cc-pVDZ after appropriate scaling method seem to coincide satisfactorily with the experimental observations rather than B3LYP/6-311g(d,p) results. The theoretical spectrograms for FT-IR and FT-Raman spectra of 4AAP have been also constructed and compared with the experimental spectra. Additionally, thermodynamic data have also been calculated and discussed.

Antipyrine clearance in comparison to conventional liver function tests in hepatitis C virus patients

In this study, 15 healthy volunteers and 96 patients with hepatitis C virus, classified according to Child-Pugh into 36 Child-A, 31 Child-B and 29 Child-C, were examined. All subjects ingested 600 mg antipyrine in the form of hard gelatinous capsules after overnight fasting. One milliliter of saliva was collected at 4 and 24 h after ingestion of antipyrine and analyzed using high-performance liquid chromatography. Blood samples were collected from all subjects for examination, using conventional liver function tests. The pharmacokinetic variables for antipyrine were determined using the two concentration time points selected. A cut-off value of 0.34 ml/min/kg was used to distinguish between cirrhotic and non-cirrhotic patients. Alanine aminotransferase, aspartate aminotransferase and gamma-glutamyl transferase values were significantly higher with significantly lower antipyrine clearance in Child-A, B, and C patients than in normal volunteers. The total protein concentration was significantly lower in Child-B and C patients. Moreover, AST was significantly higher in Child-C patients and antipyrine clearance was lower in Child-B and C patients than in Child-A patients. Antipyrine clearance showed a significant negative correlation with Child-Pugh scores, total protein, the international normalization ratio of prothrombin time and globulin, and a positive correlation with albumin and albumin-to-globulin ratio. Unlike most of the conventional liver function tests, antipyrine clearance, which represents the intrinsic clearance capacity of the liver, measured using saliva, proved to be a sensitive marker of liver function. It was significantly impaired in the Child-Pugh group A patients with the least hepatic impairment. The international normalization ratio of prothrombin time was just as informative as antipyrine clearance in identifying minimal hepatic impairment.

Regulation of theCYP1A1Gene by 2,3,7,8-Tetrachlorodibenzo-p-dioxin but Not by β-Naphthoflavone or 3-Methylcholanthrene Is Altered in Hepatitis C Virus Replicon-Expressing Cells

Exposure to hepatitis C virus (HCV) can lead to the development of cirrhosis and hepatocellular carcinoma. To examine the effects of long-term HCV infection on hepatic cytochrome P450 1A1 (CYP1A1) expression and function, we used a human hepatoma cell line expressing the HCV subgenomic replicon (Huh.8) to evaluate CYP1A1 induction by the aryl hydrocarbon receptor (AhR) ligand, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). In this study, we demonstrate that the induction of CYP1A1 expression in Huh.8 cells by TCDD but not by beta-naphthoflavone or 3-methylcholanthrene was significantly diminished. TCDD exposure of Huh.8 cells resulted in greater than 55% suppression of CYP1A1 transcription compared with the parent cell line Huh7, whereas protein levels and enzyme activities were further diminished. Suppression of CYP1A1 mRNA expression in TCDD-treated Huh.8 cells was partially reversed after pretreatment with the antioxidants N-acetylcysteine and nordihydroguaiaretic acid, suggesting a role for oxidative stress. Induced CYP1A1 message, protein, and enzyme activity were partially restored in an Huh7 cell line expressing the HCV replicon containing a deletion in the nonstructural protein NS5A. Furthermore, adenoviral expression of NS5A in Huh7 partially suppressed TCDD-induced CYP1A1 protein and enzyme activity, implicating this protein in the mechanism of suppression. These findings demonstrate that TCDD-mediated AhR signaling is impaired in hepatocytes in which HCV is present and that NS5A alone or in the presence of other nonstructural proteins of the subgenomic replicon is in part responsible.

Antiretroviral drug pharmacokinetics in hepatitis with hepatic dysfunction

Chronic viral hepatitis is common among persons with HIV-1 infection, because of shared modes of transmission, and coinfection results in accelerated liver damage, compared with persons with chronic viral hepatitis alone. The use of highly active antiretroviral therapy (HAART) has led to a significant decrease in the morbidity and mortality associated with HIV-1 infection. A number of the medications that are commonly used in HAART regimens are metabolized by the hepatic CYP enzymes, which raises the possibility of significant interactions between antiretroviral medications and hepatic impairment induced by chronic viral hepatitis. Although the data are still very scant, the pharmacokinetics of several antiretroviral medications have been shown to be significantly altered in the presence of liver disease. In the present report, we review the available data and consider potential options, such as dose adjustment and therapeutic drug monitoring, for the administration of antiretroviral therapy to patients with significant hepatic impairment.

Impairment of metabolic function in chronic hepatitis C is related to factors associated with resistance to therapy

OBJECTIVE

Liver disease causes a loss of hepatic function, and remission is associated with improved functional hepatic mass. The object of the present study was to investigate whether liver metabolic function assessed by antipyrine clearance is related to other disease characteristics influencing response to therapy in chronic hepatitis C.

METHODS

Patients (n = 96) received three different treatment regimens: one group received interferon alfa-2b for 48 wk; in a second group with maintained positive hepatitis C virus (HCV) RNA after 12 wk, interferon was combined for 36 wk with oral ribavirin; and patients who were relapsers or nonresponders to a previous therapy with interferon alone received interferon alfa-2b plus ribavirin for 48 wk.

RESULTS

Twenty-five patients (26%) showed sustained normalization of ALT levels and negative HCV RNA 6 months after therapy. The response was more likely to be sustained in patients with a genotype other than 1 (52.0% vs 15.5% in patients with genotype 1, p < 0.001), and the percentage of sustained responders was higher among patients who demonstrated negativity of HCV RNA at the end of 4 wk of treatment (64% vs 13% without negativity, p < 0.001). Sustained response was associated with significantly lower baseline serum ferritin (-46%, p < 0.01) and duration of infection (-33%, p < 0.01). Baseline antipyrine clearance was higher in sustained responders than in nonresponders (+19%, p < 0.05) and lower in genotype 1 patients than in those with a genotype other than 1 (-24%, p < 0.05). Antipyrine clearance increased by 12% at the end of the 48-wk course of treatment among sustained responders (+34% vs nonresponders, p < 0.001) and still remained elevated at the end of the follow-up (+35% vs nonresponders, p < 0.001).

CONCLUSION

In summary, the present study shows that liver oxidative metabolism is related to antiviral response rates and suggests that much of the effect is explained by viral genotype.

Antipyrine clearance in chronic and neoplastic liver diseases: a study of 518 patients

Antipyrine metabolism is widely used as an index of the drug-metabolizing reserve of the liver. It is well known that metabolism of this drug is impaired in subjects with acute hepatitis or cirrhosis, but conflicting data have been reported regarding patients with chronic postinfectious hepatitis or liver cancer. We studied conventional liver-function parameters and antipyrine metabolism (antipyrine per o.s. 18 mg/kg) in 518 subjects. One hundred and one patients had liver metastases (various primaries). Based on the number and size of lesions, the hepatic involvement was considered minimal in 47 and massive in 54 (groups B1 and B2, respectively). One hundred and two had chronic active hepatitis (CAH); 51 patients with histological evidence of fibrosis/early cirrhosis and 51 patients were without histological evidence of fibrosis/early cirrhosis. Ninety-two had histologically confirmed cirrhosis (group D), and the remaining 120 had cirrhosis and hepatocellular carcinoma (group E). The control group was composed of 103 subjects with healthy livers (group A). Antipyrine clearance (AP Cl) in CAH patients with fibrosis (0.246 +/- 0.98 mL/min per kg) was similar to that observed in patients with cirrhosis (0.223 +/- 0.148 mL/min per kg), and both values were significantly lower than that found in CAH patients without fibrosis (0.406 +/- 0.159 mL/min per kg, P < 0.01). Antipyrine clearance in patients with liver metastases (0.426 +/- 0.174 mL/min per kg) was similar to that of the healthy group (0.489 +/- 0.210 mL/min per kg). Cirrhotics and cirrhotics with hepatocellular carcinoma (HCC) presented similar degrees of impairment. Antipyrine clearance was positively correlated with serum albumin (r2 = 0.10, P = 0.01) and prothrombin time (r2 = 0.129, P < 0.01) in all groups, except those with liver metastases. In patients with CAH, the presence of fibrosis/cirrhosis is associated with impaired antipyrine metabolism. The lack of impairment in groups with liver metastases suggests that the functional hepatic reserve is maintained even in the presence of massive neoplastic invasion.