Metabolomic Characteristics of Nontuberculous Mycobacterial Pulmonary Disease.

BACKGROUND: The therapeutic challenges posed by nontuberculous mycobacterial pulmonary disease (NTM-PD) contribute to an unmet medical need. In this study, we aimed to investigate NTM-PD-specific metabolic pathways using serum metabolomics to understand disease pathogenesis. METHODS: Mass spectrometry-based untargeted metabolomic profiling of serum from patients with NTM-PD (n = 50), patients with bronchiectasis (n = 50), and healthy controls (n = 60) was performed. Selected metabolites were validated by an independent cohort and subjected to pathway analysis and classification modeling. RESULTS: Leucine, tyrosine, inosine, proline, 5-oxoproline, and hypoxanthine levels increased in the NTM-PD group compared with the healthy control group. Furthermore, levels of antioxidant metabolites (ferulic acid, α-lipoic acid, biotin, and 2,8-phenazinediamine) decreased in patients with NTM-PD. These changes were associated with arginine- and proline-related metabolism, leading to generation of reactive oxygen species. Interestingly, the observed metabolic changes in the NTM-PD group overlapped with those in the bronchiectasis group. CONCLUSION: In NTM-PD, 11 metabolites linked to increased oxidative stress were significantly altered from those in healthy controls. Our findings enhance a comprehensive understanding of NTM-PD pathogenesis and provide insights for novel treatment approaches.

Differences in Brain Metabolite Profiles Between Normothermia and Hypothermia.

BACKGROUND: This study evaluated the difference in brain metabolite profiles between normothermia and hypothermia reaching 25°C in humans in vivo. METHODS: Thirteen patients who underwent thoracic aorta surgery under moderate hypothermia were prospectively enrolled. Plasma samples were collected simultaneously from the arteries and veins to estimate metabolite uptake or release. Targeted metabolomics based on liquid chromatographic mass spectrometry and direct flow injection were performed, and changes in the profiles of respective metabolites from normothermia to hypothermia were compared. The ratios of metabolite concentrations in venous blood samples to those in arterial blood samples (V/A ratios) were calculated, and log2 transformation of the ratios [log2(V/A)] was performed for comparison between the temperature groups. RESULTS: Targeted metabolomics were performed for 140 metabolites, including 20 amino acids, 13 biogenic amines, 10 acylcarnitines, 82 glycerophospholipids, 14 sphingomyelins, and 1 hexose. Of the 140 metabolites analyzed, 137 metabolites were released from the brain in normothermia, and the release of 132 of these 137 metabolites was decreased in hypothermia. Two metabolites (dopamine and hexose) showed constant release from the brain in hypothermia, and 3 metabolites (2 glycophospholipids and 1 sphingomyelin) showed conversion from release to uptake in hypothermia. Glutamic acid demonstrated a distinct brain metabolism in that it was taken up by the brain in normothermia, and the uptake was increased in hypothermia. CONCLUSION: Targeted metabolomics demonstrated various degrees of changes in the release of metabolites by the hypothermic brain. The release of most metabolites was decreased in hypothermia, whereas glutamic acid showed a distinct brain metabolism.

Effect of haemodialysis on the pharmacokinetics and pharmacodynamics of evogliptin.

AIM: To investigate the possible effect of haemodialysis (HD) on the pharmacokinetic (PK) and pharmacodynamic (PD) characteristics of evogliptin, a dipeptidyl peptidase-4 (DPP-4) inhibitor. METHODS: A single-dose, open-label, parallel-group study of eight end-stage renal disease (ESRD) patients and eight matched healthy subjects was conducted. ESRD patients received a single oral dose of evogliptin 5 mg after and before HD with a 2-week washout between each dose, and healthy subjects received a single oral dose of evogliptin 5 mg. Serial blood, dialysate, and urine samples were collected to assess the PK and PD profiles of evogliptin. To compare PK parameters before and after HD, geometric mean ratios (GMRs) and 90% confidence intervals (CIs) were calculated. RESULTS: The GMRs for the maximum concentration and area under the concentration-time curve from time 0 to the last measurable timepoint (AUClast ) of evogliptin when administered before HD compared with after HD were 0.7293 (90% CI 0.6171-0.8620) and 0.9480 (90% CI 0.8162-1.1010), respectively. The maximum DPP-4 inhibitory effect, area under the DPP-4 inhibitory effect-time curve, and time duration of more than 80% DPP-4 inhibition were comparable when evogliptin was administered before and after HD. Compared with healthy subjects, the mean AUClast of evogliptin was approximately 1.4-fold greater in ESRD patients, but the difference is unlikely to affect the safety and efficacy of evogliptin. CONCLUSION: The effect of HD on the PK and PD characteristics of evogliptin was not clinically significant; therefore, dose adjustment according to HD status is not necessary.

Pharmacokinetics of dexmedetomidine in pediatric patients undergoing cardiac surgery with cardiopulmonary bypass.

BACKGROUND: Cardiopulmonary bypass can affect the pharmacokinetics of anesthetic agents. AIMS: We aimed to evaluate the pharmacokinetics of dexmedetomidine for infants and small children undergoing cardiac surgery with cardiopulmonary bypass based on population pharmacokinetics. METHODS: We enrolled 30 pediatric cardiac surgical patients in this study. After anesthetic induction with atropine (0.02 mg/kg), thiopental sodium (5 mg/kg), and fentanyl (2-3 µg/kg), we administered 1 µg/kg of dexmedetomidine for 10 min, followed by administration of 0.5 µg/kg of dexmedetomidine per hour during surgery. At the initiation of cardiopulmonary bypass, 1 µg/kg of dexmedetomidine was infused over 5 min. Arterial blood was obtained at predefined time points. A pharmacokinetic model was developed using NONMEM. Theory-based allometric scaling with fixed exponents was applied. Weight, age, post-menstrual age, fat-free mass, whether to implement cardiopulmonary bypass and temperature were explored as covariates. RESULTS: A total of 376 blood samples were obtained from 29 children (age: 20.3 ± 19.3 months, weight: 9.7 ± 4.1 kg). A two-compartment mammillary model with third compartment associated cardiopulmonary bypass procedure best explained the pharmacokinetics of dexmedetomidine. The pharmacokinetic parameter estimates (95% CI) standardized to a 70-kg person were as follows: V1 (L) = 31.6 (17.9-39.5), V2 (L) = 90.1 (44.0-330), Cl (L/min) = 1.08 (0.70-1.25), Q (L/min) = 2.0 (1.05-3.46). Volume for third compartment associated cardiopulmonary bypass procedure (L) = 39.4 (19.3-50.9). Clearance was not influenced by the presence of cardiopulmonary bypass in this model. CONCLUSION: When cardiopulmonary bypass is applied, the plasma concentration of dexmedetomidine decreases due to an increase in the volume of distribution, so a loading dose is required to maintain the previous concentration.

A pilot study to investigate the utility of NAT2 genotype-guided isoniazid monotherapy regimens in NAT2 slow acetylators.

Isoniazid is a therapeutic agent for the treatment of latent tuberculosis infection. Genetic variants in the N-acetyltransferase 2 (NAT2) are associated with the safety and pharmacokinetics of isoniazid. The study aimed to evaluate the safety and pharmacokinetics of a NAT2 genotype-guided regimen of isoniazid monotherapy. A randomized, open-label, parallel-group and multiple-dosing study was performed in healthy subjects. The subjects received isoniazid for 29 days. The NAT2 slow acetylators (NAT2*5/*5, -*5/*6, -*5/*7, -*6/*6, -*6/*7, -*7/*7) randomly received standard dose (300 mg, standard-treatment group) or reduced dose (200 mg, PGx-treatment group) of isoniazid. Also, all the NAT2 rapid acetylators (NAT2*4/*4) received isoniazid 300 mg (reference group). The safety and pharmacokinetics were evaluated during the study. The PGx-treatment group showed a more stable serum liver enzyme profile and a lower incidence of adverse drug reactions (ADRs) than the standard-treatment group. The emergence rates of ADRs were 12.5, 60 and 33.3% in the reference, standard-treatment and PGx-treatment groups, respectively. The PGx-treatment group showed higher plasma isoniazid concentrations than the reference group, although the PGx-treatment group received a reduced dose of isoniazid. Our results showed that a NAT2 genotype-guided regimen may reduce ADRs during isoniazid monotherapy without concern over insufficient drug exposure.

Comparative pharmacokinetics of Theracurmin, a highly bioavailable curcumin, in healthy adult subjects.

OBJECTIVE: Theracurmin is a submicron dispersed formulation of curcumin, which was developed to increase the bioavailability of curcumin. This study aimed to compare the pharmacokinetics of curcumin administered as two Theracurmin powder products and unformulated curcumin powder. MATERIALS AND METHODS: This randomized, three-treatment, six-sequence, and three-period crossover study enrolled 24 healthy subjects. Blood sampling was done until 12 hours after the administration of Theracurmin and curcumin powder to assess pharmacokinetics using a non-compartmental method. The plasma concentration of curcumin was determined using high-performance liquid chromatography coupled with tandem mass spectrometry. RESULTS: The median time to reach the maximum concentration was 1.5 - 3 hours for Theracurmin and 8 hours for curcumin powder. The two Theracurmin products showed systemic exposure profiles that were comparable to each other. The exposure ratio of Theracurmin to curcumin powder was 18.4 - 20.5 for the maximum plasma concentration and 35.9 - 42.6 for the area under the concentration-time curve from dosing to the last measurable time. CONCLUSION: In conclusion, this study showed similar systemic exposure between the two Theracurmin products. The absorption of curcumin after the administration of Theracurmin was significantly enhanced compared with curcumin powder.

Indoxyl sulfate-induced TNF-α is regulated by crosstalk between the aryl hydrocarbon receptor, NF-κB, and SOCS2 in human macrophages.

Indoxyl sulfate (IS) is a uremic toxin associated with increased prevalence of cardiovascular diseases (CVDs) in patients with chronic kidney disease. Despite the crucial role of uremia-related immune dysfunction, a majority of studies attempting to elucidate its pathogenic role in CVD have focused on IS-mediated endothelial dysfunction. Thus, we investigated the underlying molecular mechanisms involved in IS-induced production of TNF-α, a major cardiotoxic cytokine, by human macrophages. We found that crosstalk between the aryl hydrocarbon receptor (AhR), NF-κB, and the suppressor of cytokine signaling (SOCS)2 is important for TNF-α production in IS-stimulated human macrophages. IS-activated AhR rapidly associates with the p65 NF-κB subunit, resulting in mutual inhibition of AhR and NF-κB and inhibition of TNF-α production at an early time point. Later, this repression of TNF-α production is alleviated when SOCS2, a negative modulator of NF-κB, is directly induced by IS-activated AhR. In addition, once free of inhibition, activated AhR induces TNF-α expression by interacting with AhR binding sites in the TNF-α gene. Lastly, we confirmed decreased AhR and increased SOCS2 expression in monocytes of patients with end-stage renal disease, indicating the activation of AhR. Taken together, our results suggest that IS-induced TNF-α production in macrophages is regulated through a complicated mechanism involving interaction of AhR, NF-κB, and SOCS2.-Kim, H. Y., Yoo, T.-H., Cho, J.-Y., Kim, H. C., Lee, W.-W. Indoxyl sulfate-induced TNF-α is regulated by crosstalk between the aryl hydrocarbon receptor, NF-κB, and SOCS2 in human macrophages.

Gut microorganisms and their metabolites modulate the severity of acute colitis in a tryptophan metabolism-dependent manner.

PURPOSE: Growing evidence shows that nutrient metabolism affects inflammatory bowel diseases (IBD) development. Previously, we showed that deficiency of indoleamine 2,3-dioxygenase 1 (Ido1), a tryptophan-catabolizing enzyme, reduced the severity of dextran sulfate sodium (DSS)-induced colitis in mice. However, the roles played by intestinal microbiota in generating the differences in disease progression between Ido1+/+ and Ido1-/- mice are unknown. Therefore, we aimed to investigate the interactions between the intestinal microbiome and host IDO1 in governing intestinal inflammatory responses. METHODS: Microbial 16s rRNA sequencing was conducted in Ido1+/+ and Ido1-/- mice after DSS treatment. Bacteria-derived tryptophan metabolites were measured in urine. Transcriptome analysis revealed the effects of the metabolite and IDO1 expression in HCT116 cells. Colitis severity of Ido1+/+ was compared to Ido1-/- mice following fecal microbiota transplantation (FMT). RESULTS: Microbiome analysis through 16S-rRNA gene sequencing showed that IDO1 deficiency increased intestinal bacteria that use tryptophan preferentially to produce indolic compounds. Urinary excretion of 3-indoxyl sulfate, a metabolized form of gut bacteria-derived indole, was significantly higher in Ido1-/- than in Ido1+/+ mice. Transcriptome analysis showed that tight junction transcripts were significantly increased by indole treatment in HCT116 cells; however, the effects were diminished by IDO1 overexpression. Using FMT experiments, we demonstrated that bacteria from Ido1-/- mice could directly attenuate the severity of DSS-induced colitis. CONCLUSIONS: Our results provide evidence that a genetic defect in utilizing tryptophan affects intestinal microbiota profiles, altering microbial metabolites, and colitis development. This suggests that the host and intestinal microbiota communicate through shared nutrient metabolic networks.

External Validation of a Pharmacokinetic Model of Propofol for Target-Controlled Infusion in Children under Two Years Old.

BACKGROUND: Previously, a linked pharmacokinetic-pharmacodynamic model (the Kim model) of propofol with concurrent infusion of remifentanil was developed for children aged 2-12 years. There are few options for pharmacokinetic-pharmacodynamic model of propofol for children under two years old. We performed an external validation of the Kim model for children under two years old to evaluate whether the model is applicable to this age group. METHODS: Twenty-four children were enrolled. After routine anesthetic induction, a continuous infusion of 2% propofol and remifentanil was commenced using the Kim model. The target effect-site concentration of propofol was set as 2, 3, 4, and 5 µg/mL, followed by arterial blood sampling after 10 min of each equilibrium. Population estimates of four parameters-pooled bias, inaccuracy, divergence, and wobble-were used to evaluate the performance of the Kim model. RESULTS: A total of 95 plasma concentrations were used for evaluation of the Kim model. The population estimate (95% confidence interval) of bias was -0.96% (-8.45%, 6.54%) and that of inaccuracy was 21.0% (15.0%-27.0%) for the plasma concentration of propofol. CONCLUSION: The pooled bias and inaccuracy of the pharmacokinetic predictions are clinically acceptable. Therefore, our external validation of the Kim model indicated that the model can be applicable to target-controlled infusion of propofol in children younger than 2 years, with the recommended use of actual bispectral index monitoring in clinical settings that remifentanil is present. TRIAL REGISTRATION: Clinical Research Information Service Identifier: KCT0001752.

A Comprehensive Proteomic and Phosphoproteomic Analysis of Retinal Pigment Epithelium Reveals Multiple Pathway Alterations in Response to the Inflammatory Stimuli.

Overwhelming and persistent inflammation of retinal pigment epithelium (RPE) induces destructive changes in the retinal environment. However, the precise mechanisms remain unclear. In this study, we aimed to investigate RPE-specific biological and metabolic responses against intense inflammation and identify the molecular characteristics determining pathological progression. We performed quantitative analyses of the proteome and phosphoproteome of the human-derived RPE cell line ARPE-19 after treatment with lipopolysaccharide (LPS) for 45 min or 24 h using the latest isobaric tandem-mass tags (TMTs) labeling approach. This approach led to the identification of 8984 proteins, of which 261 showed a 1.5-fold change in abundance after 24 h of treatment with LPS. A parallel phosphoproteome analysis identified 20,632 unique phosphopeptides from 3207 phosphoproteins with 3103 phosphorylation sites. Integrated proteomic and phosphoproteomic analyses showed significant downregulation of proteins related to mitochondrial respiration and cell cycle checkpoint, while proteins related to lipid metabolism, amino acid metabolism, cell-matrix adhesion, and endoplasmic reticulum (ER) stress were upregulated after LPS stimulation. Further, phosphorylation events in multiple pathways, including MAPKK and Wnt/ß-catenin signalings, were identified as involved in LPS-triggered pathobiology. In essence, our findings reveal multiple integrated signals exerted by RPE under inflammation and are expected to give insight into the development of therapeutic interventions for RPE disorders.

Ursodeoxycholic acid exerts hepatoprotective effects by regulating amino acid, flavonoid, and fatty acid metabolic pathways.

INTRODUCTION: Ursodeoxycholic acid (UDCA) is an intestinal bacterial metabolite with hepatoprotective effects. However, molecular mechanisms underlying its effects remain unclear. OBJECTIVES: The aim of this study was to investigate the mechanisms underlying the therapeutic effects of UDCA by using global metabolomics analyses in healthy subjects. METHODS: Healthy Korean men were administered UDCA at dosage of 400, 800, or 1200 mg daily for 2 weeks. Serum samples were collected and used for liver function tests and to determine miR-122 expression levels. Urinary and plasma global metabolomics analyses were conducted using a liquid chromatography system coupled with quadrupole-time-of-flight mass spectrometry (LC/QTOFMS) and gas chromatography-TOFMS (GC/TOFMS). Unsupervised multivariate analysis (principal component analysis) was performed to identify discriminative markers before and after treatment. RESULTS: Alanine transaminase score and serum miR-122 levels decreased significantly after 2 weeks of treatment. Through LC- and GC-based metabolomic profiling, we identified 40 differential metabolites in plasma and urine samples. CONCLUSIONS: Regulation of liver function scores and metabolic alternations highlight the potential hepatoprotective action of UDCA, which were primarily associated with amino acid, flavonoid, and fatty acid metabolism in healthy men.

Comparison of the Plasma Metabolome Profiles Between the Internal Thoracic Artery and Ascending Aorta in Patients Undergoing Coronary Artery Bypass Graft Surgery Using Gas Chromatography Time-of-Flight Mass Spectrometry.

BACKGROUND: The left internal thoracic artery (LITA) has been used as the first conduit of choice in coronary artery bypass grafting (CABG) because of excellent long-term patency and outcomes. However, no studies have examined substances other than nitric oxide that could be beneficial for the bypass conduit, native coronary artery or ischemic myocardium. This study was conducted to evaluate differences in metabolic profiles between the LITA and ascending aorta using gas chromatography-time of flight-mass spectrometry (GC-TOF-MS). METHODS: Twenty patients who underwent CABG using the LITA were prospectively enrolled. Plasma samples were collected simultaneously from the LITA and ascending aorta. GC-TOF-MS based untargeted metabolomic analyses were performed and a 2-step volcano plot analysis was used to identify distinguishable markers from two plasma metabolome profiles. Semi-quantitative and quantitative analyses were performed using GC-TOF-MS and enzyme-linked immunosorbent assay, respectively, after selecting target metabolites based on the metabolite set enrichment analysis. RESULTS: Initial volcano plot analysis demonstrated 5 possible markers among 851 peaks detected. The final analysis demonstrated that the L-cysteine peak was significantly higher in the LITA than in the ascending aorta (fold change = 1.86). The concentrations of intermediate metabolites such as L-cysteine, L-methionine and L-cystine in the 'cysteine and methionine metabolism pathway' were significantly higher in the LITA than in the ascending aorta (2.0-, 1.4- and 1.2-fold, respectively). Quantitative analysis showed that the concentration of hydrogen sulfide (H2S) was significantly higher in the LITA. CONCLUSION: The plasma metabolome profiles of the LITA and ascending aorta were different, particularly higher plasma concentrations of L-cysteine and H2S in the LITA.

The Genetic Polymorphism UGT1A4*3 Is Associated with Low Posaconazole Plasma Concentrations in Hematological Malignancy Patients Receiving the Oral Suspension.

The metabolism of posaconazole is mediated mainly by uridine 5'-diphospho-glucuronosyltransferase (UGT) enzymes, especially UGT1A4. The aim of this study was to investigate the effects of genetic polymorphisms on the posaconazole plasma concentration (PPC). This prospective study was conducted from September 2014 to August 2016. We enrolled patients with acute myeloid leukemia or myelodysplastic syndrome treated with posaconazole oral suspension (200 mg) three times daily for fungal prophylaxis. The patients were examined for the multidrug resistance gene 1 3435C>T and 2677G>T/A variations and the UGT1A4*3 allele by direct sequencing of DNA from peripheral whole-blood samples. We defined poor absorbers to be those with PPCs of <200 ng/ml and the optimal PPC to be ≥700 ng/ml on day 8. The associations between genetic polymorphisms and the PPC were evaluated using multivariate logistic regression analysis including clinical variables. During the study period, 132 patients were enrolled. Six patients (4.5%) were defined as poor absorbers, and 49 patients (37.1%) did not reach the optimal PPC on day 8. In multivariate analysis, the independent risk factors for a poor absorber were at least one UGT1A4*3 allele (adjusted odds ratio [aOR], 18.81; 95% confidence interval [CI], 1.09 to 324.44; P = 0.043) and poor oral food intake (aOR per -100 kcal, 1.44; 95% CI, 1.04 to 1.99; P = 0.029). There was no statistically significant association between the genetic polymorphisms and achievement of the optimal PPC on day 8. The UGT1A4*3 polymorphism is an independent risk factor for being a poor absorber of posaconazole oral suspension in patients with hematological malignancies.

Early Therapeutic Drug Monitoring of Posaconazole Oral Suspension in Patients With Hematologic Malignancies.

BACKGROUND: Therapeutic drug monitoring (TDM) of posaconazole is usually performed 1 week after starting the drug because of its long half-life. However, previous studies showed that measuring the posaconazole plasma concentration (PPC) on day 3 is effective for predicting steady-state levels. The purpose of this study was to evaluate the relevance of early TDM (day 3) of posaconazole for achieving an optimal PPC. METHODS: This prospective study was conducted from September 2014 to August 2016. A total of 148 patients with acute myeloid leukemia or myelodysplastic syndromes received a 200 mg posaconazole oral suspension 3 times daily for fungal prophylaxis. During the period from September 2014 to December 2015 (control group), no dose adjustment was performed on day 3. During the period from January 2016 to Aug 2016 (early TDM group), the frequency of posaconazole 200-mg administration was increased to 4 times daily in patients whose PPC on day 3 was <400 ng/mL. The cutoff value for optimal PPC on day 8 was defined as 500 ng/mL. RESULTS: In 21 of 107 patients (20%) in the control group, PPC was <400 ng/mL on day 3. In 15 (71%) of these 21 patients, the PPC was suboptimal on day 8. In the early TDM group, the PPC was <400 ng/mL on day 3 in 4 of 41 patients (10%). After increasing the posaconazole administration frequency in these 4 patients, PPC was suboptimal on day 8 in 1 patient (25%). In both groups, 104 patients had a PPC of ≥500 ng/mL on day 3, but 7% (7/104) of these had a suboptimal level on day 8. CONCLUSIONS: Early TDM on day 3 for posaconazole suspension may help more patients achieve optimal drug levels on day 8, although TDM on day 8 is needed even in patients with optimal levels on day 3.

GM-CSF Induces Inflammatory Macrophages by Regulating Glycolysis and Lipid Metabolism.

GM-CSF induces proinflammatory macrophages, but the underlying mechanisms have not been studied thus far. In this study, we investigated the mechanisms of how GM-CSF induces inflammatory macrophages. First, we observed that GM-CSF increased the extent of LPS-induced acute glycolysis in murine bone marrow-derived macrophages. This directly correlates with an inflammatory phenotype because glycolysis inhibition by 2-deoxyglucose abolished GM-CSF-mediated increase of TNF-α, IL-1ß, IL-6, and IL-12p70 synthesis upon LPS stimulation. Increased glycolytic capacity is due to de novo synthesis of glucose transporter (GLUT)-1, -3, and -4, as well as c-myc. Meanwhile, GM-CSF increased 3-hydroxy-3-methyl-glutaryl-CoA reductase, which is the rate-limiting enzyme of the mevalonate pathway. Inhibition of acute glycolysis or 3-hydroxy-3-methyl-glutaryl-CoA reductase abrogated the inflammatory effects of GM-CSF priming in macrophages. Finally, mice with inflamed colons exposed to dextran sodium sulfate containing GLUT-1high macrophages led to massive uptake of [18F]-fluorodeoxyglucose, but GM-CSF neutralization reduced the positron-emission tomography signal in the intestine and also decreased GLUT-1 expression in colonic macrophages. Collectively, our results reveal glycolysis and lipid metabolism created by GM-CSF as the underlying metabolic constructs for the function of inflammatory macrophages.

A pharmacokinetic drug-drug interaction study between pregabalin and tramadol in healthy volunteers.

PURPOSE: Combination therapy of pregabalin and tramadol is used to treat chronic neuropathic pain; however, the pharmacokinetic (PK) interactions of these drugs has not been studied. This study aimed to evaluate PK interactions between pregabalin and tramadol and the safety of combination therapy. METHODS: A randomized, open-label, multiple-dose, three-treatment, three-period, six-sequence cross-over study was conducted in healthy subjects. All subjects received the following three treatments for 4 days in each period: pregabalin 150 mg twice daily; tramadol extended-release (ER) 200 mg in the morning, and 100 mg in the evening; and co-administration of pregabalin 150 mg and tramadol ER 200 mg in the morning, and pregabalin 150 mg and tramadol ER 100 mg in the evening. RESULTS: A total of 21 subjects completed the study with no clinically significant safety issues. For pregabalin, the geometric mean ratio (GMR) (90% CI; confidence interval) of combination therapy to monotherapy for maximum concentration at steady state (Cmax,ss) and area under the concentration curve from 0 to dosing interval time at steady state (AUCτ,ss) were 0.8801 (0.8043-0.9632) and 1.0830 (1.0569-1.1098), respectively. The corresponding values for tramadol were 1.0177 (0.9839-1.0526) and 1.0152 (0.9896-1.0414), respectively. The GMR (90% CI) of combination therapy to monotherapy of O-desmethyl-tramadol for Cmax,ss and AUCτ,ss was 1.0465 (1.0095-1.0848) and 1.0361 (1.0001-1.0734), respectively. CONCLUSIONS: There were no significant drug interactions between pregabalin and tramadol, considering that all of the 90% CI of PK measures were within the conventional bioequivalence range. Both drugs were well tolerated when administered concomitantly.

Effect of food on the pharmacokinetics of YH4808, a potassium-competitive acid blocker, after single- and multiple-oral dosing in healthy subjects.

PURPOSE: YH4808 is a potassium-competitive acid blocker, developed for the treatment of acid-related disorders. Two clinical studies in healthy male subjects were conducted to evaluate the effect of food on the pharmacokinetics of YH4808. METHODS: The first study, a randomized, three-treatment, three-period, crossover study, compared pharmacokinetics of YH4808 (300 mg) after a single dose at fed state with a standard or a high-fat meal to those at fasted state. The second study, a randomized, two-treatment, two-period, crossover study, investigated pharmacokinetics at fasted or fed state with a standard meal after twice daily dose of YH4808 (100 mg) for 7 days. Bloods for pharmacokinetic evaluation were sampled up to 48 h post-dose and 24 h post-dose at steady state, respectively. The pharmacokinetic parameters were estimated by non-compartmental method. RESULTS: After single dosing, the geometric means of maximum plasma concentration increased by 1.2 and 2.1 times in the fed states with a standard meal and a high-fat meal, respectively, of that in fasted state. Corresponding values of area under the plasma concentration-time curve (AUC) from time 0 to the last measurable time point increased by 1.8 and 2.8 times, respectively. After multiple dosing, the geometric mean for 24-h AUC at steady state slightly increased in fed state by 1.1 times of that in fasted state. CONCLUSIONS: As fat content of the food increased, the systemic exposure of YH4808 after single dosing increased. However, systemic exposures at steady state after multiple dosing between fasted and fed states were similar. TRIAL REGISTRATION: ClinicalTrials.gov registry no.: NCT01520012.

Assessment of Hepatic Cytochrome P450 3A Activity Using Metabolic Markers in Patients with Renal Impairment.

BACKGROUND: The renal function of individuals is one of the reasons for the variations in therapeutic response to various drugs. Patients with renal impairment are often exposed to drug toxicity, even with drugs that are usually eliminated by hepatic metabolism. Previous study has reported an increased plasma concentration of indoxyl sulfate and decreased plasma concentration of 4ß-hydroxy (OH)-cholesterol in stable kidney transplant recipients, implicating indoxyl sulfate as a cytochrome P450 (CYP) inhibiting factor. In this study, we aimed to evaluate the impact of renal impairment severity-dependent accumulation of indoxyl sulfate on hepatic CYP3A activity using metabolic markers. METHODS: Sixty-six subjects were enrolled in this study; based on estimated glomerular filtration rate (eGFR), they were classified as having mild, moderate, or severe renal impairment. The plasma concentration of indoxyl sulfate was quantified using liquid chromatography-mass spectrometry (LC-MS). Urinary and plasma markers (6ß-OH-cortisol/cortisol, 6ß-OH-cortisone/cortisone, 4ß-OH-cholesterol) for hepatic CYP3A activity were quantified using gas chromatography-mass spectrometry (GC-MS). The total plasma concentration of cholesterol was measured using the enzymatic colorimetric assay to calculate the 4ß-OH-cholesterol/cholesterol ratio. The correlation between variables was assessed using Pearson's correlation test. RESULTS: There was a significant negative correlation between MDRD eGFR and indoxyl sulfate levels. The levels of urinary 6ß-OH-cortisol/cortisol and 6ß-OH-cortisone/cortisone as well as plasma 4ß-OH-cholesterol and 4ß-OH-cholesterol/cholesterol were not correlated with MDRD eGFR and the plasma concentration of indoxyl sulfate. CONCLUSION: Hepatic CYP3A activity may not be affected by renal impairment-induced accumulation of plasma indoxyl sulfate.

Integrative Analysis of Renal Ischemia/Reperfusion Injury and Remote Ischemic Preconditioning in Mice.

Remote ischemic preconditioning (RIPC) is a strategy to induce resistance in a target organ against the oxidative stress and injury caused by ischemia and reperfusion (IR). RIPC harnesses the body's endogenous protective capabilities through brief episodes of IR applied in organs remote from the target. Few studies have analyzed this phenomenon in the kidney. Furthermore, the window of protection representing RIPC efficacy has not been fully elucidated. Here, we performed a multiomics study to specify those associated with protective effects of RIPC against the IR injury. A total of 30 mice were divided to four groups: sham, IR only, late RIPC + IR, and early RIPC + IR. We found that IR clearly led to tubular injury, whereas both preconditioning groups exhibited attenuated injury after the insult. In addition, renal IR injury produced changes of the metabolome in kidney, serum, and urine specimens. Furthermore, distinctive mRNA and associated protein expression changes supported potential mechanisms. Our findings revealed that RIPC effectively reduces renal damage after IR and that the potential mechanisms differed between the two time windows of protection. These results may potentially be extended to humans to allow non- or minimally invasive diagnosis of renal IR injury and RIPC efficacy.

Pharmacokinetics and Tolerance of the Phage Endolysin-Based Candidate Drug SAL200 after a Single Intravenous Administration among Healthy Volunteers.

This study was a phase 1, single-center, randomized, double-blind, placebo-controlled, single-dosing, and dose-escalating study of intravenous SAL200. It is a new candidate drug for the treatment of antibiotic-resistant staphylococcal infections based on a recombinant form of the phage endolysin SAL-1. The study evaluated the pharmacokinetics, pharmacodynamics, and tolerance among healthy male volunteers after the intravenous infusion of single ascending doses of SAL200 (0.1, 0.3, 1, 3, and 10 mg/kg of body weight). SAL200 was well tolerated, and no serious adverse events (AEs) were observed in this clinical study. Most AEs were mild, self-limiting, and transient. The AEs reported in more than three participants were fatigue, rigors, headache, and myalgia. No clinically significant values with respect to the findings of clinical chemistry, hematology, and coagulation analyses, urinalysis, vital signs, and physical examinations were observed, and no notable trends in our electrocardiogram (ECG) results for any tested dose were noticed. A greater-than-dose-proportional increase with regard to systemic exposure and the maximum serum concentration was observed when the SAL200 dose was increased from 0.1 mg/kg to 10 mg/kg. This investigation constitutes the first-in-human phase 1 study of an intravenously administered, phage endolysin-based drug. (This study has been registered at ClinicalTrials.gov under identifier NCT01855048 and at the Clinical Research Information Service [https://cris.nih.go.kr/cris/] under identifier KCT0000968.).