Characterization of 15 CYP2J2 variants identified in the Chinese Han population on the metabolism of ebastine and terfenadine in vitro.

Genetic polymorphism of the cytochrome P450 (CYP) gene can significantly influence the metabolism of endogenous and xenobiotic compounds. However, few studies have focused on the polymorphism of CYP2J2 and its impact on drug catalytic activity, especially in the Chinese Han population. In this study, we sequenced the promoter and exon regions of CYP2J2 in 1,163 unrelated healthy Chinese Han individuals using the multiplex PCR amplicon sequencing method. Then, the catalytic activities of the detected CYP2J2 variants were evaluated after recombinant expression in S. cerevisiae microsomes. As a result, CYP2J2*7, CYP2J2*8, 13 variations in the promoter region and 15 CYP2J2 nonsynonymous variants were detected, of which V15A, G24R, V68A, L166F and A391T were novel missense variations. Immunoblotting results showed that 11 of 15 CYP2J2 variants exhibited lower protein expression than wild-type CYP2J2.1. In vitro functional analysis results revealed that the amino acid changes of 14 variants could significantly influence the drug metabolic activity of CYP2J2 toward ebastine or terfenadine. Specifically, 4 variants with relatively higher allele frequencies, CYP2J2.8, 173_173del, K267fs and R446W, exhibited extremely low protein expression and defective catalytic activities for both substrates. Our results indicated that a high genetic polymorphism of CYP2J2 could be detected in the Chinese Han population, and most genetic variations in CYP2J2 could influence the expression and catalytic activity of CYP2J2. Our data significantly enrich the knowledge of genetic polymorphisms in CYP2J2 and provide new theoretical information for corresponding individualized medication in Chinese and other Asian populations.

Effects of Simvastatin on the Metabolism of Vonoprazan in Rats Both in vitro and in vivo.

Purpose: To study the potential drug-drug interactions between simvastatin and vonoprazan and to provide the scientific basis for rational use of them in clinical practice. Methods: An incubation system was established with rat liver microsomes, and the main metabolite of vonoprazan M-I was detected by UPLC-MS/MS. The IC50 value of simvastatin was then calculated and its inhibitory mechanism against vonoprazan was also analyzed. Twelve SD rats were randomly divided into 2 groups, then they were given simvastatin or saline for 2 weeks continuously. On the day of the experiment, both groups were intragastrically administered with vonoprazan once, followed by the collection of blood at different time points. Then the plasma concentration of vonoprazan and M-I in rats were detected by UPLC-MS/MS. Results: In vitro experiments revealed that simvastatin could inhibit the metabolism of vonoprazan, and its inhibition type belonged to the mixed non-competitive and competitive inhibition model. In vivo experiments in rats demonstrated that the area under concentration time curve (AUC) of vonoprazan was decreased but the clearance (CLz/F) of it was increased in the simvastatin administrated group, as compared to those of the control group. However, M-I in simvastatin treated group exhibited the higher AUC and lower CLz/F values compared to those in the control group. These data indicated that multiple doses of simvastatin administration could reduce the plasma concentration of vonoprazan and accelerate its metabolic rate in rats. Conclusion: Simvastatin could inhibit the metabolism of vonoprazan in vitro but multiple doses of simvastatin exhibited the opposite effect In vivo. Altogether, our data indicated that an interaction existed between simvastatin and vonoprazan and additional cares might be taken when they were co-administrated in clinic.

Functional characterization of the defective CYP2C9 variant CYP2C9*18.

Cytochrome P450 2C9 (CYP2C9) is one of the most important drugs metabolizing enzymes and accounts for the metabolism of about 13%-17% of clinical drugs. Like other members in CYP2 family, CYP2C9 gene exhibits great genetic polymorphism among different races and individuals. CYP2C9*18 is one CYP2C9 allelic variant identified in a Southeast Asian population and is estimated to cause the amino acid substitutions of I359L and D397A in CYP2C9 enzyme simultaneously. Limited by the low expression level in bacteria and COS-7 cells, no valuable enzyme kinetics have been reported on this CYP2C9 variant. In this study, the baculovirus-based system was used for the high expression of recombinant CYP2C9 s in insect cells. As a result, together with I359L substitution, D397A could significantly decrease the protein expression of CYP2C9.18 in insect cells, although substitution of D397A alone had no effect on the expression of CYP2C9 in vitro. As compared with that of wild-type enzyme, both CYP2C9.18 variant and D397A variant could decrease more than 80% of the catalytic activity of CYP2C9 enzyme toward three probe substrates, suggesting that caution should be exercised when patients carrying CYP2C9*18 taking medicines metabolized by CYP2C9 enzyme with a narrow therapeutic window.

The association between vitamin D deficiency and community-acquired pneumonia: A meta-analysis of observational studies.

Emerging evidence has shown that vitamin D deficiency may be related with community-acquired pneumonia (CAP), but individually published studies showed inconclusive results. The aim of this study was to quantitatively summarize the association between vitamin D and the CAP.We conducted this meta-analysis though a systematic literature search of PubMed, Medline, and EMBASE up to 31 September 2018 with the following keywords 'vitamin D' or 'cholecalciferol' or '25-hydroxyvitamin D' or '25(OH)D' in combination with 'community-acquired pneumonia' or 'CAP' or 'pneumonia' with no limitations. This meta-analysis was performed following the guidelines of Meta-analysis of Observational Studies in Epidemiology. The association between vitamin D levels and CAP were measured as odds ratio (OR) and weighted mean difference (WMD). Results were combined using a random-effect or a fix-effect meta-analysis, and sensitivity analyses were conducted to explore potential factors.Eight observational studies involving 20,966 subjects were included. In this meta-analysis, CAP patients with vitamin D deficiency (serum 25(OH)D levels <20 ng/mL) experienced a significantly increased risk of CAP (odds ratio (OR) = 1.64, 95% confidence intervals (CI): 1.00, 2.67), and an obvious decrease of -5.63 ng/mL (95% CI: -9.11, -2.14) in serum vitamin D was demonstrated in CAP patients. Sensitivity analysis showed that exclusion of any single study did not materially alter the overall combined effect.The evidence from this meta-analysis indicates an association between vitamin D deficiency and an increased risk of CAP patients. However, well-designed trails are required to determine the explicit effect of vitamin D supplementation.

Silibinin affects the pharmacokinetics of methadone in rats.

The aim of the present study was to investigate the pharmacokinetic effect of silibinin on methadone in rats. Twenty-four male Sprague-Dawley rats were randomly divided into 4 groups: control group, single dose of 100 mg/kg group, multiple doses of 100 mg/kg group, and multiple doses of 30 mg/kg group. A single dose of 6 mg/kg methadone was administrated to rats orally without or with silibinin. Plasma samples were collected via tail vein at different time points and concentrations of methadone and its metabolite, 2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine (EDDP), were determined by ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). Compared with the control group (without silibinin), both 30 and 100 mg/kg silibinin significantly increased the Cmax of methadone, but only 100 mg/kg silibinin significantly increased the AUC(0-t) of methadone and decreased its clearance. Pharmacokinetics parameters of EDDP were not altered by 30 mg/kg silibinin; its Tmax was decreased by 100 mg/kg silibinin and the Cmax was increased by single dose of 100 mg/kg silibinin. It is concluded that silibinin significantly altered the pharmacokinetics of methadone in rats by increasing the exposure of methadone. Further investigations in human should be conducted. Therapeutic drug monitoring of methadone in individuals undergoing methadone maintenance therapy is recommended when silibinin is concomitant.

Identification and characterization of a novel CYP2C9 allelic variant in a warfarin-sensitive patient.

AIM: To determine the genetic basis of the low warfarin dose requirement in a Chinese patient. MATERIALS & METHODS: Bi-directional sequencing of CYP2C9, VKORC1 and CYP4F2 genes was performed. CYP2C9 variants were highly expressed in yeast and insect-cell microsomes. Three typical CYP2C9 probe drugs were used to evaluate the catalytic activity. RESULTS: A novel missense mutation (1400 T>C) was identified in CYP2C9 and had been named as new allele *60. When expressed in yeast and insect cells, compared with wild-type enzyme, variant CYP2C9.60 exhibited lower protein expression capacity and showed significantly decreased metabolic activities for the hydroxylation of S-warfarin, tolbutamide and diclofenac. CONCLUSION: The novel mutation can greatly decrease the enzymatic activity of the CYP2C9 enzyme both in vitro and in vivo.

[Value of plasma beta-Glucan in early diagnosis of invasive fungal infection in children].

OBJECTIVE: The incidence of invasive fungal infection (IFI) has risen dramatically along with the prolongation of immunocompromised individuals' lifespan. This study aimed to investigate the incidence of IFI among high risk pediatric patients and to evaluate the diagnostic value of circulating (1,3)-beta-D-glucan (BG) in IFI. METHODS: High risk pediatric inpatients from hemato-oncology department and ICU were enrolled from November 2007 to June 2008. All the patients had persistent fever for 4 to 7 days or longer. Circulating BG levels were detected once or twice weekly until the signs and symptoms improved, or IFI was excluded, or death. Circulating BG levels were determined by the GKT-5M Set Kinetic Fungus Detection Kit. Detection of plasma BG was judged positive when the level was > or = 10 pg/mL. RESULTS: A total of 130 patients were enrolled. Two patients with candidemia were classified as proven IFI, 20 as probale IFI,7 as possible IFI, and 101 without IFI. The patients with proven or probable IFI had a longer length of hospital stay (P< 0.05) and an increased mortality rate (P< 0.05). The patients with IFI demonstrated a higher plasma level of BG than those without IFI (P< 0.01). The sensitivity, specificity, positive and negative predictive values for plasma BG detction were 81.8%, 82.4%, 48.6% and 95.7% respectively. Positive BG results occurred before the abnormal results on computed tomography scan or fungal culture or simultaneously in 72.2% of the cases. CONCLUSIONS: IFI is not rare among pediatric high-risk patients. Circulating BG detection is accurate to a certain extent in the diagnosis of IFI. It is a useful adjunct means for IFI screening in high-risk patients.

[Overview of clinical occurrence of primary immunodeficiency disorders in children].

OBJECTIVE: More than one hundred primary immunodeficiency disorders have been discovered so far. But the incidence of these disorders in our country is still not clear, so we analyzed the clinical data of 93 children with primary immunodeficiency disorders seen in our hospital in recent 30 years to understand the occurrence of primary immunodeficiency disorders in children, to promote the clinicians to become familiar with these disorders, to improve the nationwide registry system and to establish the basis for the treatment and prevention in future. METHODS: To analyze the constituent ratio of the 93 children with primary immunodeficiency disorders seen in our hospital from 1974 to 2003, diagnostic and classification criteria were set by taking the proposal by International Union of Immunological Societies (IUIS) PID classification committee in 2003 into account. All the data were analyzed retrospectively. RESULTS: In the 93 children with primary immunodeficiency disorders, antibody deficiencies were the most frequent (39.8%) finding, followed by combined immunodeficiency, combined T- and B-cell disorders (22.6%), and T lymphocytic deficiencies alone (14.0%). Immunodeficiency with other major defects accounted for 12.9%, phagocytic disorders 9.7%, and complement deficiencies 1.1%. Thus, there seemed to be a tendency that the incidence increased with time. The incidence of these disorders has increased significantly as shown by 50 diagnosed cases in children with these disorders since 1996. Sixteen children died, with the highest mortality occurred with combined immunodeficiency. Seven children developed bronchiectasis. Two children suffered from persistent diarrhea while one of the two was complicated with persistent intestinal fistula. One child developed juvenile rheumatoid arthritis, another one with granulocytopenia and iridocyclitis, and the other with allergic purpura. The boys: girls ratio for all disorders was 3:1. The age of onset ranged from 10 days to 37 years of age. CONCLUSIONS: There are vast variety of primary immunodeficiency disorders in our area and antibody deficiency is the most common abnormality. Combined immunodeficiency has early onset age and high mortality rate. With the great improvement of the diagnostic techniques, these disorders have become a group of important disorders and all the clinicians should pay great attention to these disorders.