Wonku Kang

Assessment of adherence to the CONSORT statement for quality of reports on randomized controlled trial abstracts from four high-impact general medical journals

BackgroundThe extended Consolidated Standards of Reporting Trials (CONSORT) Statement for Abstracts was developed to improve the quality of reports of randomized controlled trials (RCTs) because readers often base their assessment of a trial solely on the abstract. To date, few data exist regarding whether it has achieved this goal. We evaluated the extent of adherence to the CONSORT for Abstract statement for quality of reports on RCT abstracts by four high-impact general medical journals.MethodsA descriptive analysis of published RCT abstracts in The New England Journal of Medicine (NEJM), The Lancet, The Journal of American Medical Association (JAMA), and the British Medical Journal (BMJ) in the year 2010 was conducted by two reviewers, independently extracting data from a MEDLINE/PubMed search.ResultsWe identified 271 potential RCT abstracts meeting our inclusion criteria. More than half of the abstracts identified the study as randomized in the title (58.7%; 159/271), reported the specific objective/hypothesis (72.7%; 197/271), described participant eligibility criteria with settings for data collection (60.9%; 165/271), detailed the interventions for both groups (90.8%; 246/271), and clearly defined the primary outcome (94.8%; 257/271). However, the methodological quality domains were inadequately reported: allocation concealment (11.8%; 32/271) and details of blinding (21.0%; 57/271). Reporting the primary outcome results for each group was done in 84.1% (228/271). Almost all of the abstracts reported trial registration (99.3%; 269/271), whereas reports of funding and of harm or side effects from the interventions were found in only 47.6% (129/271) and 42.8% (116/271) of the abstracts, respectively.ConclusionsThese findings show inconsistencies and non-adherence to the CONSORT for abstract guidelines, especially in the methodological quality domains. Improvements in the quality of RCT reports can be expected by adhering to existing standards and guidelines as expressed by the CONSORT group.

Bioequivalence and tolerability of two clopidogrel salt preparations, besylate and bisulfate: a randomized, open-label, crossover study in healthy Korean male subjects.

BACKGROUND Clopidogrel, a potent antiplatelet agent, reduces the risk for thrombotic events in patients with atherothrombotic diseases. Clopidogrel is marketed primarily as a bisulfate salt. A different salt preparation of clopidogrel, clopidogrel besylate, has been developed and might provide an additional treatment option for patients. OBJECTIVE The aim of this study was to compare the pharmacokinetic, pharmacodynamic, and tolerability profiles of clopidogrel besylate with those of clopidogrel bisulfate to determine bioequivalence for the purposes of marketing approval. METHODS A randomized, open-label, 2-period, single- and multiple-dose, comparative crossover study was conducted in healthy Korean male subjects. The subjects received either clopidogrel bisulfate or clopidogrel besylate as a single 300-mg oral loading dose (day 1) followed by a 75-mg/d (once daily) maintenance dose on days 2 to 6. After a 15-day washout period, subjects were administered the alternative salt preparation according to the same protocol. The plasma concentrations of clopidogrel and its primary metabolite (SR26334) were assessed using high-performance liquid chromatography/tandem mass spectrometry after administration of the loading dose. The platelet aggregation response to 10-mumol/L adenosine diphosphate was measured using turbidometric aggregometry during the single- and multiple-dosing periods and at steady state (day 6). Tolerability was monitored using physical examination, including vital sign measurements, and laboratory analysis. RESULTS Forty-four subjects were enrolled and completed the study (mean [SD] age, 24.3 [2.7] years; weight, 70.0 [8.2] kg). The mean values for C(max), T(max), and AUC(0-t) with clopidogrel (parent drug) of clopidogrel besylate (5.2 ng/mL, 0.9 hour, and 10.1 ng/mL/h, respectively) were similar to those with clopidogrel bisulfate (5.4 ng/mL, 0.9 hour, and 10.3 ng/mL/h). The mean values for Cmax, AUC(0-t), and AUC(0-infinity) with the SR26334 of clopidogrel besylate (10.9 microg/mL, 38.8 microg/mL/h, and 43.0 microg/mL/h, respectively) were not significantly different from those with the SR26334 of clopidogrel bisulfate (11.9 microg/mL, 40.6 microg/mL/h, and 43.8 microg/mL/h). The mean values for maximal antiplatelet effect (Emax) and area under the time-effect curve (AUEC) with the 2 clopidogrel salt preparations were as follows: clopidogrel besylate, 58.8 h . % and 4299.1 h . % inhibition, respectively; and clopidogrel bisulfate, 61.7 h . % and 4406.9 h . % inhibition; these differences were not statistically significant. The 90% CIs for the ratios of the log-transformed C(max), AUC, E(max), and AUEC values were within the predetermined bioequivalence range of 80% to 125%. Three adverse events (6.8%) were reported during the study and included abdominal discomfort (1 subject [2.3%] in the group that received clopidogrel bisulfate), easy fatigability (1 subject [2.3%] immediately before administration of loading dose of clopidogrel besylate), and thrombocytopenia (1 subject [2.3%] in the group receiving the clopidogrel bisulfate). All adverse events were transient and mild. CONCLUSIONS In these healthy Korean male subjects, the differences in the pharmacokinetic and pharmacodynamic properties between the 2 clopidogrel salt preparations did not reach statistical significance and met the regulatory requirements for bioequivalence. Both preparations were well tolerated.

Globular adiponectin inhibits ethanol-induced apoptosis in HepG2 cells through heme oxygenase-1 induction.

Hepatocellular apoptosis is an essential pathological feature of alcoholic liver disease. Adiponectin, an adipokine predominantly secreted from adipose tissue, has been shown to play beneficial roles in alcoholic liver disease against various inflammatory and pro-apoptotic molecules. However, the effects of adiponectin on ethanol-induced apoptosis in liver cells are largely unknown. Herein, we investigated the role of globular adiponectin (gAcrp) in the prevention of ethanol-induced apoptosis and further tried to decipher the potential mechanisms involved. In the present study, we demonstrated that gAcrp significantly inhibits both ethanol-induced increase in Fas ligand expression and activation of caspase-3 in human hepatoma cell lines (HepG2 cells), suggesting that gAcrp plays a protective role against ethanol-induced apoptosis in liver cells. This protective effect of gAcrp was mediated through adiponectin receptor R1 (adipoR1). Further, globular adiponectin treatment caused induction of heme oxygenase-1 (HO-1) through, at least in part, nuclear factor (erythroid-derived 2)-like 2, (Nrf2) signaling. Treatment with SnPP, a pharmacological inhibitor of HO-1, and knockdown of HO-1 with small interfering RNA (siRNA) restored caspase-3 activity suppressed by gAcrp, indicating a critical role of HO-1 in mediating the protective role of gAcrp in ethanol-induced apoptosis in liver cells. In addition, carbon monoxide, a byproduct obtained from the catabolism of free heme was found to contribute to the anti-apoptotic effect of adiponectin. In conclusion, these data demonstrated that globular adiponectin prevents ethanol-induced apoptosis in HepG2 cells via HO-1 induction and revealed a novel biological response of globular adiponectin in the protection of liver injury from alcohol consumption.

The CYP3A4*18 allele, the most frequent coding variant in asian populations, does not significantly affect the midazolam disposition in heterozygous individuals.

The objective of this study was to identify CYP3A4 variants in Koreans and to characterize their functional consequences in vitro and in vivo. Four single nucleotide polymorphisms were identified in 50 Koreans by direct DNA sequencing. In an additional genotyping using 248 subjects, CYP3A4*18 was confirmed as the most frequent coding variant in Koreans at 1.7%, and its frequency was similar to that of Asians, suggesting that CYP3A4*18 would be the highest coding variant in Asians. The recombinant CYP3A4.18 protein prepared in baculovirus expression system showed 67.4% lower Vmax and 1.8-fold higher Km for midazolam 1′-hydroxylation compared with the wild type. The mean values of Cmax and area under the concentration curve (AUC) in the CYP3A4*1/*18 and CYP3A5*1/*3 subjects (n = 8) were 63% and 32% higher than in CYP3A4*1/*1 and CYP3A5*1/*3 carriers (n = 8), respectively. Although the in vitro assay exhibited a significant reduction of the enzyme activity for midazolam, the in vivo differences associated with the CYP3A4*1/*18 tend to be low (P < 0.07 in Cmax and P < 0.09 in AUC). In summary, the heterozygous CYP3A4*1/*18 does not appear to cause a significant change of midazolam disposition in vivo; however, the clinical relevance of CYP3A4*18/*18 remains to be evaluated.

Low molecular weight fucoidan improves endoplasmic reticulum stress-reduced insulin sensitivity through AMP-activated protein kinase activation in L6 myotubes and restores lipid homeostasis in a mouse model of type 2 diabetes.

Low molecular weight fucoidan (LMWF) is widely used to treat metabolic disorders, but its physiologic effects have not been well determined. In the present study, we investigated the metabolic effects of LMWF in obese diabetic mice (leptin receptor–deficient db/db mice) and the underlying molecular mechanisms involved in endoplasmic reticulum (ER) stress-responsive L6 myotubes. The effect of LMWF-mediated AMP-activated protein kinase (AMPK) activation on insulin resistance via regulation of the ER stress-dependent pathway was examined in vitro and in vivo. In db/db mice, LMWF markedly reduced serum glucose, triglyceride, cholesterol, and low-density lipoprotein levels, and gradually reduced body weights by reducing lipid parameters. Furthermore, it effectively ameliorated glucose homeostasis by elevating glucose tolerance. In addition, the phosphorylation levels of AMPK and Akt were markedly reduced by ER stressor, and subsequently, glucose uptake and fatty acid oxidation were also reduced. However, these adverse effects of ER stress were significantly ameliorated by LMWF. Finally, in L6 myotubes, LMWF markedly reduced the ER stress-induced upregulation of the mammalian target of rapamycin–p70S61 kinase network and subsequently improved the action of insulin via AMPK stimulation. Our findings suggest that AMPK activation by LMWF could prevent metabolic diseases by controlling the ER stress-dependent pathway and that this beneficial effect of LMWF provides a potential therapeutic strategy for ameliorating ER stress-mediated metabolic dysfunctions.

Proteomic analysis of breast cancer tissues to identify biomarker candidates by gel-assisted digestion and label-free quantification methods using LC-MS/MS

This study presents a proteomic method that differentiates between matched normal and breast tumor tissues from ductal carcinoma in situ (DCIS) and invasive carcinoma from Korean women, to identify biomarker candidates and to understand pathogenesis of breast cancer in protein level. Proteins from tissues obtained by biopsy were extracted by RIPA buffer, digested by the gel-assisted method, and analyzed by nano-UPLC-MS/MS. From proteomic analysis based on label-free quantitation strategy, a non-redundant list of 298 proteins was identified from the normal and tumor tissues, and 244 proteins were quantified using IDEAL-Q software. Hierarchical clustering analysis showed two patterns classified as two groups, invasive carcinoma and DCIS, suggesting a difference between two carcinoma at the protein expression level as expected. Differentially expressed proteins in tumor tissues compared to the corresponding normal tissues were related to three biological pathways: antigen-processing and presentation, glycolysis/gluconeogenesis, and complement and coagulation cascades. Among them, the up-regulation of calreticulin (CRT) and protein disulfide isomerase A3 (PDIA3) was confirmed by Western blot analysis. In conclusion, this study showed the possibility of identifying biomarker candidates for breast cancer using tissues and might help to understand the pathophysiology of this cancer at the protein level.

Integrative analysis of proteomic and transcriptomic data for identification of pathways related to simvastatin-induced hepatotoxicity

Hepatocytes are used widely as a cell model for investigation of xenobiotic metabolism and the toxic mechanism of drugs. Simvastatin is the first statin drug used extensively in clinical practice for control of elevated cholesterol or hypercholesterolemia. However, it has also been reported to cause adverse effects in liver due to cellular damage. In this study, for proteomic and transcriptomic analysis, rat primary hepatocytes were exposed to simvastatin at IC20 concentration for 24 h. Among a total of 607 differentially expressed proteins, 61 upregulated and 29 downregulated proteins have been identified in the simvastatin‐treated group. At the mRNA level, results of transcriptomic analysis revealed 206 upregulated and 41 downregulated genes in the simvastatin‐treated group. Based on results of transcriptomic and proteomic analysis, NRF2‐mediated oxidative stress response, xenobiotics by metabolism of cytochrome P450, fatty acid metabolism, bile metabolism, and urea cycle and inflammation metabolism pathways were focused using IPA software. Genes (FASN, UGT2B, ALDH1A1, CYP1A2, GSTA2, HAP90, IL‐6, IL‐1, FABP4, and ABC11) and proteins (FASN, CYP2D1, UG2TB, ALDH1A1, GSTA2, HSP90, FABP4, and ABCB11) related to several important pathways were confirmed by real‐time PCR andWestern blot analysis, respectively. This study will provide new insight into the potential toxic pathways induced by simvastatin.

Biotransformation of geniposide by human intestinal microflora on cytotoxicity against HepG2 cells.

Intestinal microflora (IM) is able to produce toxic and carcinogenic metabolites and induce more potent cytotoxicity against cells than non-metabolites. This study was performed to investigate the cytotoxic responses of geniposide (GS) and its metabolite and to determine the role of metabolism by IM in GS-induced cytotoxicity. Genipin (GP), a GS metabolite, increased cytotoxic effects in cells, but GS did not. Following GS incubation with IM for metabolic activation, increased cytotoxicity was detected compared to GS. Western blot analysis revealed that the activated GS inhibited Bcl-2 expression with a subsequent increase in Bax expression. Likewise, GS activation by IM stimulated caspase-3 and the production of reactive oxygen species (ROS). In addition, activated GS-induced apoptosis was confirmed by apoptosis and ROS assays; N-acetyl-l-cysteine (NAC) suppressed ROS production and apoptotic cell death. Activated GS induced sustained JNK phosphorylation. Moreover, activated GS-induced cell death was reversed by SP600125. Taken together, these findings suggest that human IM is able to metabolize GS into GP, and the related biological activities induce apoptosis through ROS/JNK signaling.

Pharmacokinetic evaluation and modeling of formulated levodopa intranasal delivery systems

Levodopa (L-dopa), the metabolic precursor of dopamine, has primarily been used for the treatment of Parkinsons disease (PD) in combination with carbidopa (C-dopa). This study aims to investigate the feasibility of L-dopa nasal delivery systems prepared using maleic acid solution containing 2-hydroxypropyl-beta-cyclodextrin, and to develop pharmacokinetic models. Following oral or intravenous administration of L-dopa plus C-dopa and intranasal dosing of L-dopa in the presence and absence of C-dopa to the rat, the concentrations of L-dopa in plasma and brain were determined using HPLC. The pharmacokinetic profiles were analyzed using non-compartmental and compartmental modeling approaches. Simultaneous nonlinear regression was performed to improve the identifiability of model parameters. L-Dopa was rapidly absorbed into blood and brain. The absolute bioavailabilities of oral and nasal preparations containing C-dopa were 17.7 and 45.4%, respectively. C-dopa caused a 1.2-fold decrease in the elimination rate of L-dopa, indicating decreased metabolism. Although the half-life after nasal administration was relatively short (less than 30 min) in both blood and brain regardless of C-dopa addition, the systemic exposure was promising due to rapid absorption. In conclusion, the L-dopa nasal delivery system could be used as a good rescue therapy for PD patients who experience symptom fluctuation with oral L-dopa administration.

CYP2J2 and CYP2C19 Are the Major Enzymes Responsible for Metabolism of Albendazole and Fenbendazole in Human Liver Microsomes and Recombinant P450 Assay Systems

ABSTRACT Albendazole and fenbendazole are broad-spectrum anthelmintics that undergo extensive metabolism to form hydroxyl and sulfoxide metabolites. Although CYP3A and flavin-containing monooxygenase have been implicated in sulfoxide metabolite formation, the enzymes responsible for hydroxyl metabolite formation have not been identified. In this study, we used human liver microsomes and recombinant cytochrome P450s (P450s) to characterize the enzymes involved in the formation of hydroxyalbendazole and hydroxyfenbendazole from albendazole and fenbendazole, respectively. Of the 10 recombinant P450s, CYP2J2 and/or CYP2C19 was the predominant enzyme catalyzing the hydroxylation of albendazole and fenbendazole. Albendazole hydroxylation to hydroxyalbendazole is primarily mediated by CYP2J2 (0.34 μl/min/pmol P450, which is a rate 3.9- and 8.1-fold higher than the rates for CYP2C19 and CYP2E1, respectively), whereas CYP2C19 and CYP2J2 contributed to the formation of hydroxyfenbendazole from fenbendazole (2.68 and 1.94 μl/min/pmol P450 for CYP2C19 and CYP2J2, respectively, which are rates 11.7- and 8.4-fold higher than the rate for CYP2D6). Correlation analysis between the known P450 enzyme activities and the rate of hydroxyalbendazole and hydroxyfenbendazole formation in samples from 14 human liver microsomes showed that albendazole hydroxylation correlates with CYP2J2 activity and fenbendazole hydroxylation correlates with CYP2C19 and CYP2J2 activities. These findings were supported by a P450 isoform-selective inhibition study in human liver microsomes. In conclusion, our data for the first time suggest that albendazole hydroxylation is primarily catalyzed by CYP2J2, whereas fenbendazole hydroxylation is preferentially catalyzed by CYP2C19 and CYP2J2. The present data will be useful in understanding the pharmacokinetics and drug interactions of albendazole and fenbendazole in vivo.