Keiko Ohno

Meta-Analysis of Risk of Malignancy with Immunosuppressive Drugs in Inflammatory Bowel Disease

Background: There is a concern as to whether long-term administration of immunosuppressants in patients with inflammatory bowel disease (IBD) would increase the risk of malignancy. Objective: To compare the risks of developing malignancy between patients with IBD treated with immunosuppressive agents and patients with IBD not receiving these agents. Methods: A systematic literature review was conducted, and a meta-analysis was performed on data retrieved from cohort studies that followed patients with IBD who received immunosuppressive agents for more than a year and documented the incidence of newly developed malignancy. An electronic search was conducted using MEDLINE (1966–September 2006), the Cochrane Library (issue 3, 2006), and Japana Centra Revuo Medicina (1981–September 2006). Medical subject headings used in the searches were azalhioprine, 6-mercaptopurine, cyclosporine, methotrexate, tacrolimus, inflammatory bowel disease, and neoplasms. We imposed no language limitation in the searches. Additionally, a manual search of reference listings from all articles retrieved from the electronic databases was performed. Using data obtained from control groups or population-based studies, the incidence of newly developed malignancy in patients with IBD treated with immunosuppressive agents was compared with that of patients with IBD who were not receiving immunosuppressive agents. Statistical analysis for the change in risk of developing malignancy was performed using the weighted mean difference (WMD) normalized to per person-year and its 95% confidence interval. Results: Nine cohort studies met the inclusion criteria for this meta-analysis. Analysis of these studies showed no discernible difference (WMD −0.3 × 10-3/person-year; 95% CI −1.2 × 10-3 to 0.7 × 10-3) in the incidence of any kind of malignancy in patients with IBD who received immunosuppressants compared with those who did not receive immunosuppressants. No significant difference in WMD was observed when the data from patients with either Crohns disease (CD) or ulcerative colitis (UC) were analyzed separately. Conclusions: Our findings suggest that the administration of immunosuppressive agents in patients with either CD or UC probably does not confer a significantly increased risk of malignancy compared with patients with IBD who are not receiving these agents.

Optimal prophylactic dosage and disposition of micafungin in living donor liver recipients.

Abstract:  Micafungin, a new candin antifungal drug, has a good safety profile and a significant therapeutic effect against Candida and Aspergillus. Little is known, however, about the optimal prophylactic dosage and the disposition of micafungin in liver transplant recipients, or about the effect of continuous venovenous hemodialysis (CVVH) on the pharmacokinetics of micafungin. Six living donor liver transplant patients were enrolled in this study. The mean Cmax and Cmin (trough) values of micafungin in plasma were 6.31 ± 1.08 and 1.65 ± 0.54 μg/mL, respectively. The mean elimination half‐life (t1/2) and mean area under the curve up to 12 h post‐dosing (AUC 0–12 h) were 13.63 ± 2.77 h and 50.04 ± 6.48 μg·h/mL, respectively. The concentrations of micafungin at the inlet and outlet of the dialyzer were very similar. The mean (±SD) ratio of micafungin concentrations at the inlet and outlet of the dialyzer (coutlet/cinlet) and the clearance of micafungin were 0.96 ± 0.04 and 0.054 ± 0.04 mL/min/kg, respectively. The amount in the ultrafiltrate was 1.0 mg. Micafungin effectively prevents systemic fungal infection in patients who have undergone liver transplantation. No significant differences were observed in the disposition of micafungin in recipients, and the therapeutic drug level can be achieved by administration of micafungin at a dosage of 40–50 mg/d. The CVVH had little effect on micafungin kinetics, and no dose adjustment or modification of dosing interval was needed during CVVH.

Comparison of cilostazol and ticlopidine for one-month effectiveness and safety after elective coronary stenting

AbstractPurpose: To compare the oral antiplatelets, phosphodiesterase III inhibitor cilostazol and the thienopyridine ticlopidine, for one-month effectiveness and safety as an adjunctive therapy after coronary stenting. Methods: Published studies retrieved through Medline and other databases from 1966–2002. Meta-analyses evaluated effectiveness and adverse side effects for one-month administrations of aspirin plus cilostazol or aspirin plus ticlopidine therapy after coronary stenting. Major adverse cardiac events (MACE), stent-associated thrombosis or adverse side effects after coronary stenting were compared between the two study arms and expressed with the odds ratios (OR) specific for the individual studies and meta-analytic summary for OR. Results: Five clinical studies met the inclusion criteria, and 4 of these studies underwent meta-analysis. With regard to the comparison of the OR summary for MACE and stent-associated thrombosis for the clinical outcome, there were no statistical significant differences between aspirin plus cilostazol and aspirin plus ticlopidine. While, the incidence of adverse side effects tended to be lower, they were not statistically significant in patients with aspirin plus cilostazol. Conclusions: Our meta-analysis results indicated that there were no differences between cilostazol (plus aspirin) and ticlopidine (plus aspirin) with regard to effectiveness and safety for a one-month period when used as an adjunctive therapy after coronary stenting.

Association of Plasma Concentration of 4β-Hydroxycholesterol with CYP3A5 Polymorphism and Plasma Concentration of Indoxyl Sulfate in Stable Kidney Transplant Recipients

Several studies have shown that renal failure decreases CYP3A activity and that uremic toxins may play a role via transcriptional or translational modifications of cytochrome P450 (P450) enzymes and direct inhibition of P450-mediated metabolism. In this study, we evaluated the relationship between CYP3A activity (using plasma concentration of 4β-hydroxycholesterol as a biomarker) and clinical characteristics including plasma concentrations of indoxyl sulfate (3-INDS) and indole-3-acetic acid (3-IAA) in stable kidney transplant recipients. Forty-five Japanese kidney transplant recipients who underwent transplantation more than 90 days prior to the study were included. Morning blood samples were collected and plasma concentrations of 4β-hydroxycholesterol, 3-INDS, and 3-IAA were measured. Plasma concentrations of 4β-hydroxycholesterol were 57.1 ± 11.2, 42.1 ± 11.8, and 34.5 ± 7.3 ng/ml in recipients with CYP3A5*1/*1 (n = 5), *1/*3 (n = 15), and *3/*3 (n = 25) genotypes, respectively, with significant differences between three genotypes. A significant correlation was observed between plasma concentrations of 4β-hydroxycholesterol and 3-INDS but not 3-IAA. Multiple regression analysis identified the number of CYP3A5*3 alleles in genotype, plasma concentration of 3-INDS, and body weight as independent variables associated with plasma concentration of 4β-hydroxycholesterol. In conclusion, these results suggest that CYP3A5 polymorphism and plasma concentration of 3-INDS may account for the interindividual variability of CYP3A activity, and that plasma concentration of 3-INDS may partially explain the gap in CYP3A activity that cannot be explained by genetic contribution in patients with renal failure.

Significant increase in plasma 4β-hydroxycholesterol concentration in patients after kidney transplantation

Several previous studies have shown that renal failure decreases not only renal elimination but also metabolic clearance of drugs, particularly those metabolized by CYP3A. However, whether recovery of renal function results in recovery of hepatic CYP3A activity remains unknown. In this study, we evaluated the effect of renal function on CYP3A activity after kidney transplantation in patients with end-stage renal disease (ESRD) by measuring the change in CYP3A activity using plasma concentration of 4β-hydroxycholesterol as a biomarker. The study enrolled 13 patients with ESRD who underwent the first kidney allograft transplantation. Morning blood samples were collected before and 3, 7, 10, 14, 21, 30, 60, 90, 120, 150 and 180 days after kidney transplantation. Plasma concentration of 4β-hydroxycholesterol was measured using GC-MS. Compared with before kidney transplantation, creatinine clearance increased significantly from day 3 after kidney transplantation and stabilized thereafter. Plasma concentration of 4β-hydroxycholesterol was elevated significantly on days 90 and 180 after kidney transplantation. In conclusion, this study suggests the recovery of CYP3A activity with improvement in renal function after kidney transplantation in patients with ESRD.

CYP3A5 polymorphism affects the increase in CYP3A activity after living kidney transplantation in patients with end stage renal disease

AIMS It has been reported that cytochrome P450 (CYP)3A activity increases significantly in patients with end stage renal disease (ESRD) after kidney transplantation, with wide interindividual variability in the degree of increase. The aim of this study was to evaluate the influence of CYP3A5 polymorphism on the increase in CYP3A activity after living kidney transplantation, by measuring the plasma concentration of 4β-hydroxycholesterol. METHODS This prospective study recruited 22 patients with ESRD who underwent a first living kidney allograft transplantation, comprising 12 patients with CYP3A5*1 allele (CYP3A5*1/*1 or *1/*3) and 10 patients without CYP3A5*1 allele (CYP3A5*3/*3). RESULTS No significant difference in estimated glomerular filtration rate over time was observed between patients with the CYP3A5*1 allele and patients without the CYP3A5*1 allele, suggesting that the degrees of recovery in renal function after living kidney transplantation were similar in the two groups. However, plasma concentrations of 4β-hydroxycholesterol on days 90 (57.1 ± 13.4 vs. 39.5 ± 10.8 ng ml(-1)) and 180 (55.0 ± 14.5 vs. 42.4 ± 12.6 ng ml(-1)) after living kidney transplantation were significantly higher in the presence of the CYP3A5*1 allele than in the absence of the CYP3A5*1 allele [P = 0.0034 (95% confidence interval of difference 6.55, 28.6) and P = 0.043 (95% confidence interval of difference 0.47, 24.8), respectively], suggesting that CYP3A activity may increase markedly associated with recovery of renal function in patients with the CYP3A5*1 allele. CONCLUSIONS These findings suggest that the presence of the CYP3A5*1 allele contributes to marked elevation of CYP3A activity associated with recovery of renal function after kidney transplantation.

Liquid chromatographic method for the determination of sirolimus in blood using electrochemical detection

Therapeutic drug monitoring of sirolimus (rapamycin) is important for immunosuppressive therapy in solid organ transplantation. We have developed a simple and reliable method for determining blood concentrations of sirolimus using reversed-phase HPLC with electrochemical detection (ECD). The E(2) potential was set at +900 mV. The potential of guard cell was set at +950 mV and that of the E(1) cell at +400 mV. The method was linear for a concentration range of 1-50 ng/mL when 0.5 mL blood was used. The correlation coefficients of all standard curves were greater than or equal to 0.999. The limit of detection was 0.5 ng/mL. The inter-assay precision ranged from 3.22 to 7.48%, and the coefficient of variation (CV) for a quality control sample at 10 ng/mL was 7.48% with a bias of 8.4% from the target value. The intra-assay precision ranged from 0.72 to 3.71%, and the CV for a quality control sample at 10 ng/mL was 0.72% with a bias of 6.8% from the target value. In a solid organ transplant recipient, trough concentrations of sirolimus were well within the analytic range of the HPLC/ECD procedure. The method described here is suitable for management of sirolimus therapy in solid organ transplantation.

A nomogram for predicting the optimal oral dosage of tacrolimus in liver transplant recipients with small-for-size grafts.

Abstract:  No optimal tacrolimus dosage regimen suitable for clinical use in liver transplant recipients has yet been established. The purpose of this study was to determine the factors affecting the optimal dosage and pharmacokinetics of tacrolimus in living donor liver transplantation, and a nomogram for optimal tacrolimus dosage in the immediate postoperative period for recipients with small‐for‐size grafts was constructed. Twenty‐four liver transplant patients (nine males and 15 females) and 24 donors (10 males and 14 females) were enrolled in this study. Two studies were performed. In study 1, the effect of the actual ratio of graft volume to standard liver volume (GV/SV ratio) on the elimination half‐life (T1/2) of tacrolimus in the immediate postoperative period was analysed, and a nomogram for estimating the optimal oral dose of tacrolimus required to reach a target concentration was established. In study 2, the effect of donor age on the recovery of hepatic function with ability of the graft to eliminate tacrolimus was analysed. In the immediate postoperative period, T1/2 of tacrolimus showed great variability between patients, with values ranging from 16.3 to 110.9 h. Graft size (GV/SV ratio) is important and could influence intraindividual variations in the optimal dosage and T1/2 of tacrolimus. The recovered T1/2 ratio (T1/2 ratio=T1/2 1–10 d/T1/2 30–40 d), this ratio being related to the recovery of hepatic function with ability of the graft to eliminate tacrolimus, showed great variability between patients, with values ranging from 1.08 to 4.21 (mean±SD, 1.95±0.81). Age of the donor is a major factor affecting the recovered ratio of the graft to metabolize tacrolimus. The nomogram that we have constructed, based on graft size (GV/SV ratio), will easily provide optimal dose for each patient with small‐for‐size graft in the early postoperative period.

A simple and reliable method for determining plasma concentration of dehydroxymethylepoxyquinomicin by high performance liquid chromatography with mass spectrometry

We have developed a simple and reliable method for determining plasma concentration of dehydroxymethylepoxyquinomicin (DHMEQ), a new low molecular weight NF-kappaB inhibitor, using high performance liquid chromatography with mass spectrometry (LC-MS). An experiment of mass spectrometry with electrospray ionization in the negative ionization mode was performed to detect ion transitions at m/z 260.05 [M-H](-) for DHMEQ and 240.29 for mefenamic acid as an internal standard. The samples were purified using liquid-liquid extraction with ethyl acetate. The method yielded a standard curve which was linear for the concentration range of 0.1-125 ng/mL when 0.05 mL plasma was used. The correlation coefficients of all standard curves were greater than or equal to 0.999. The limit of detection was 50 pg/mL (signal/noise >3). Daily fluctuation of plasma standard curve was small. The intra- and inter-assay precision ranged from 2.84 to 4.76% (n=6) and 2.91 to 7.03% (n=6), respectively. The LC-MS technique described provides a simple and reliable liquid chromatographic method for the determination of DHMEQ level and for use in studies involving pharmacokinetics.

A Simplified Method for Detecting Isoniazid Compliance in Patients Receiving Antituberculosis Chemotherapy

The objective of this study was to develop a new simplified method using thin‐layer chromatography (TLC) for determining isoniazid (INH) compliance in patients receiving antituberculosis chemotherapy. TLC was performed on silica gel plates using a standard solution of INH and acetylisoniazid (AcINH) and ethyl acetate‐methanol (70:30 v/v) as the developing solvent. The spots of compound were detected by iodine. In the human study, fractional urine samples were collected over 24 hours from 4 healthy human subjects genotyped for NAT2 and to whom 400 mg of INH were administered orally. These samples were used for TLC analysis. The results of TLC were compared with those of high‐performance liquid chromatography (HPLC). This method indicated good separation between INH and AcINH in standard solutions. The detection limits for INH and AcINH (applied volume; 20 μl of standard solution) were 2.2 nmole and 5 nmole, respectively, as detected by iodine. In the human study, the INH spot in urine was not detected on the TLC plate, except in one sample over the 0‐ to 4‐hour period from 1 volunteer. However, the AcINH spot was detected in all urine samples from all volunteers. The total experimental time from application of the urine sample to analysis on TLC was 30 minutes. The results suggest that this method for detecting AcINH on TLC is an excellent, convenient, and simple method for determining INH compliance in patients receiving standard antituberculosis chemotherapy regimen or INH preventative therapy, regardless of the patients NAT2 genotype.