Mechanism-based inhibition of Alantolactone on human cytochrome P450 3A4 in vitro and activity of hepatic cytochrome P450 in mice.

ETHNOPHARMACOLOGICAL RELEVANCE: Alantolactone (AL), one of the main active ingredients in Inula helenium L., has been included in various prescriptions of traditional Chinese medicine. The effects of AL on cytochrome P450 (CYP450) were still unclear. This study evaluated the inhibitory effect of AL on cytochrome P450s in vitro and in vivo. MATERIALS AND METHODS: The inhibitory effects of AL on the CYPs activity were evaluated in human liver microsomes (HLMs) and recombinant cDNA-expressed enzymes incubation system, and then determined by LC-MS/MS based CYPs probe substrate assay. C57BL/6 mice were treated AL orally (0, 25, 50, 100 mg/kg) for 15 days. The inhibitory effects of AL on major Cyps in mice were examined at both the mRNA and enzyme activity levels. RESULTS: AL showed a potent inhibitory effect on CYP3A4 activity with IC50 values of 3.599 (HLMs) and 3.90 (recombinant CYP3A4) µM, respectively. AL strongly decreased CYP3A4 activity in a dose-dependent but not time-dependent way in HLMs. Results from typical Lineweaver-Burk plots showed that AL could inhibit CYP3A4 activity noncompetitively, with a Ki value of 1.09 µM in HLMs. Moreover, activity of CYP2C19 could also be inhibited by AL with IC50 of 36.82 µM. Other CYP450 isoforms were not markedly affected by AL. The inhibition was also validated by in vivo study of mice. AL significantly decreased mRNA expression of Cyp2c and 3a family. CONCLUSION: The study indicates that herb-drug interaction should be paid more attention between AL and drugs metabolized by CYP3A4.

High seroprevalence of human herpesvirus type 8 in patients with end-stage renal disease in Taiwan.

BACKGROUND: Human herpesvirus type 8 (HHV-8) is the aetiologic agent of Kaposi's sarcoma (KS). The incidence of KS in renal transplant patients is much higher than in healthy controls. The risk is even higher among recipients seropositive for HHV-8 before transplantation. Patients with end-stage renal disease (ESRD) are immunocompromised and are candidates for renal transplantation, but HHV-8 seroprevalence in ESRD patients has not been well documented. OBJECTIVES: This study aimed to evaluate HHV-8 seroprevalence in ESRD patients in a cohort in Taiwan. STUDY DESIGN: Blood samples collected from 149 ESRD patients and 149 age- and sex-matched healthy controls were analysed for HHV-8 antibody with immunofluorescence assay (IFA) and enzyme-linked immunosorbent assay (ELISA) and for HHV-8 DNA with polymerase chain reaction. RESULTS: Seropositivity and titres for HHV-8 antibodies with IFA as well as seropositivity with ELISA were significantly greater in ESRD patients than in healthy controls (P=0.006, 0.001 and 0.003, respectively). Patients with a history of taking herbal medicine had significantly greater ELISA positivity than those without such a history (P=0.004). ELISA positives, particularly patients, had much higher IFA antibody titres than ELISA negatives (P<0.0001). Seropositivity in ESRD patients was not related to lymphopaenia, monocytosis, dialysis duration or a history of transfusion. Two diabetic ESRD patients were positive for HHV-8 DNA. CONCLUSIONS: ESRD patients had significantly greater HHV-8 seropositivity than healthy controls in Taiwan. This association seems to be related to the geographic location of the cohort and invites further studies for the early association of HHV-8 infection in ESRD patients and risk for KS.

Epidemiology of human papillomavirus infection and cervical cancer and future perspectives in Hong Kong, Singapore and Taiwan.

Hong Kong, Singapore and Taiwan are three island states that are newly emerged affluent economic areas in Asia. The majority of the populations are ethnically Chinese with a total population of 6.98, 4.5 and 23 million, respectively. Cervical cancer has been declining over the last thirty years in all three states and is largely attributable to widespread opportunistic cervical cancer screening. The age-standardized incidence rates of cervical cancer are 9.6 per 100,000 women in Hong Kong in 2004, 10.6 per 100,000 women in Singapore in 2002 and 18.6 per 100,000 women in Taiwan in 2003. High prevalence of human papillomavirus (HPV) was observed in all three states. In cervical cancer, HPV 16 and 18 are the two most prevalent HPV types, but HPV 58 and 52 are also highly prevalent in these three states. Important epidemiological risk factors for invasive cervical cancer include smoking and age at sexual debut for women, although this is changing towards an earlier age. Of the three states, Taiwan was the first to have a comprehensive national screening programme in 1995 followed by Hong Kong in 2002 and Singapore in 2004. Women in these three states are well aware of cervical cancer and the preventative means by Pap smear screening, although their awareness and understanding of the role of HPV in cervical carcinogenesis is low. Prophylactic HPV vaccines have been licensed in the three states. Routine comprehensive public vaccination programme for adolescent girls has yet to be adopted by the governmental agency, despite an affirmative recommendation by medical professional bodies.

Epidemiologic correlates of cervical human papillomavirus prevalence in women with abnormal Pap smear tests: a Taiwan Cooperative Oncology Group (TCOG) study.

To explore factors affecting human papillomavirus (HPV) prevalence in all grades of cervical neoplasia among Chinese women, 1,264 women with abnormal cervical cytology attending the gynaecologic clinics of 11 major medical centres in Taiwan. Patients were interviewed and underwent complete gynaecologic examination including colposcopy. Cervical scrapings were collected for HPV DNA detection by both Hybrid Capture-2 (high-risk probe) and L1 consensus PCR-reverse line blot. The prevalences of HPV in the four different diagnosis groups: (i) suspicious (n = 316), (ii) low-grade intraepithelial lesion (n = 474), (iii) high-grade intraepithelial lesion (n = 450), and (iv) cancer (n = 16), were 36.1%, 74.7%, 83.6%, and 100%, respectively. In the latter two groups, Patients less than 30 or 40 years old, respectively, tended to be infected more frequently with HPV than the older patients were. The main correlates of HPV prevalence were lifetime number of sex partners (odds ratio (OR) for two or more partners: 2.44; 95% CI, 1.44-4.15), vaginal douching after intercourse (OR for douching frequently: 1.44; 95% CI, 1.01-2.04), vitamin supplementation (OR for regular vitamin supplement: 0.71, 95% CI, 0.55-0.92), and performance of Pap smear tests (OR for never having a Pap smear performed: 2.22; 95% CI, 1.19-4.17). The risk for vaginal douching was augmented by the promiscuity of sex partners (OR of 3.19 (1.91-5.34)) and smoking (OR of 1.90 (1.15-3.13)), whereas vitamin supplementation reduced the odds ratio to 1.35 (0.85-2.15). The results of this study provide further evidence of the role of HPV in cervical carcinogenesis. The data also indicate the main areas of risk for the prevalence of HPV in cervical neoplasia in Chinese women living in Taiwan.