Significant association between HLA-B*35:01 and onset of drug-induced liver injury caused by Kampo medicines in Japanese patients.

AIM: Drug-induced liver injury (DILI) is a severe and life-threatening immune-mediated adverse effect, occurring rarely among treated patients. We examined genomic biomarkers in the Japanese population that predict the onset of DILI after using a certain class of drugs, such as Kampo products (Japanese traditional medicines). METHODS: A total of 287 patients diagnosed as DILI by hepatology specialists were recruited after written informed consent was obtained. A genome-wide association analysis and human leukocyte antigen (HLA) typing in four digits were performed. RESULTS: We found a significant association (p = 9.41 × 10-10 ) of rs146644517 (G > A) with Kampo product-related DILI. As this polymorphism is located in the HLA region, we evaluated the association of HLA types and found that 12 (63.2%) of 19 Kampo-DILI patients contained HLA-B*35:01, whereas only 15.2% were positive for this HLA among healthy volunteers. The odds ratio was 9.56 (95% confidence interval 3.75-24.46; p = 2.98 × 10-6 , corrected p = 4.17 × 10-5 ), and it increased to 13.55 compared with the DILI patients not exposed to Kampo products. The individual crude drug components in the Kampo products, including Scutellaria root (ougon in Japanese), rhubarb (daiou), Gardenia fruit (sanshishi), and Glycyrrhiza (kanzou), were significantly associated with HLA-B*35:01. CONCLUSIONS: HLA-B*35:01 is a genetic risk factor and a potential predictive biomarker for Kampo-induced DILI in the Japanese population.

Impact of the TRPV2 Inhibitor on Advanced Heart Failure in Patients with Muscular Dystrophy: Exploratory Study of Biomarkers Related to the Efficacy of Tranilast.

Cardiomyopathy is the leading cause of death in patients with muscular dystrophy (MD). Tranilast, a widely used anti-allergic drug, has displayed inhibitory activity against the transient receptor potential cation channel subfamily V member 2 and improved cardiac function in MD patients. To identify urinary biomarkers that assess improved cardiac function after tranilast administration, we performed a urinary metabolomic study focused on oxidative fatty acids. Accompanying the clinical trial of tranilast, urine specimens were collected over 24 weeks from MD patients with advanced heart failure. Urinary levels of tetranor-PGDM (tetranor-prostaglandin D metabolite), a metabolite of prostaglandin D2, significantly decreased 12 weeks after tranilast administration and were correlated with BNP. These results suggest that prostaglandin-mediated inflammation, which increases with the pathological progression of heart failure in MD patients, was attenuated. Urinary prostaglandin E3 (PGE3) levels significantly increased 4 weeks after tranilast administration. There were positive correlations between the urinary levels of PGE3 and 8-hydroxy-2'-deoxyguanosine, an oxidative stress marker. High PGE3 levels may have a protective effect against cardiomyopathy in MD patients with high oxidative stress. Although further validation studies are necessary, urinary tetranor-PGDM and PGE3 levels may help the current understanding of the extent of advanced heart failure in patients with MD after tranilast administration.

Structure of Cytochrome P450 2C9*2 in Complex with Losartan: Insights into the Effect of Genetic Polymorphism.

The human CYP2C9 plays a crucial role in the metabolic clearance of a wide range of clinical therapeutics. The *2 allele is a prevalent genetic variation in CYP2C9 that is found in various populations. A marked reduction of catalytic activity toward many important drug substrates has been demonstrated by CYP2C9*2, which represents an amino acid variation at position 144 from arginine to cysteine. The crystal structure of CYP2C9*2 in complex with an antihypertensive drug losartan was solved using X-ray crystallography at 3.1-Å resolution. The Arg144Cys variation in the *2 complex disrupts the hydrogen-bonding interactions that were observed between the side chain of arginine and neighboring residues in the losartan complex of CYP2C9 and the wild-type (WT) ligand-free structure. The conformation of several secondary structural elements is affected, thereby altering the binding and orientation of drug and important amino acid side chains in the distal active site cavity. The new structure revealed distinct interactions of losartan in the compact active site of CYP2C9*2 and differed in occupancy at the other binding sites previously identified in the WT-losartan complex. Furthermore, the binding studies in solution using losartan illustrated lower activity of the CYP2C9*2 compared with the WT. Together, the findings yield valuable insights into the decreased hydroxylation activity of losartan in patients carrying CYP2C9*2 allele and provide a useful framework to investigate the effect of a single-nucleotide polymorphism that leads to altered metabolism of diverse drug substrates. SIGNIFICANCE STATEMENT: The *2 allele of the human drug-metabolizing enzyme CYP2C9 is found in different populations and results in significantly reduced activity toward various drug substrates. How the CYP2C9*2 variant induces altered drug metabolism is poorly understood given that the Arg144Cys variation is located far away from the active site. This work yield insight into the effect of distal variation using multitude of techniques that include X-ray crystallography, isothermal titration calorimetry, enzymatic characterization, and computational studies.

Serum lipidomics for exploring biomarkers of bortezomib therapy in patients with multiple myeloma.

Although the proteasome inhibitor bortezomib (BTZ) shows excellent efficacy in multiple myeloma (MM), a fraction of patients has a suboptimal or no response to this agent. In addition, BTZ-induced peripheral neuropathy (BiPN), a frequent side-effect of this therapy, limits its use in some patients. This study aimed to explore serum lipid biomarker candidates to predict the response to BTZ and the severity of BiPN. Fifty-nine serum samples were collected from patients with MM prior to receiving BTZ plus low-dose dexamethasone therapy. Serum levels of phospholipids, sphingolipids, neutral lipids, and polyunsaturated fatty acids and their oxidation products were measured by a comprehensive lipidomic study. Overall, 385 lipid metabolites were identified in patients' sera; lower levels of several glycerophospholipids, sphingolipids, and cholesteryl esters were associated with a poor treatment response. Metabolites related to platelet-activating factor biosynthesis and cholesterol metabolism appeared particularly relevant. Furthermore, several lysophosphatidylcholines, phosphatidylcholines, ceramides, neutral lipids, and oxidative fatty acids were significantly increased or decreased in patients with BiPN grades ranging from G0 to G3. Among these compounds, mediators reportedly inducing myelin breakdown and stimulating inflammatory responses were prominent. Although further study is necessary to validate these biomarker candidates, our results contribute to the development of predictive biomarkers for response to BTZ treatment, or ensuing severe BiPN, in patients with MM.

Structural Basis of Single-Nucleotide Polymorphisms in Cytochrome P450 2C9.

Single-nucleotide polymorphisms in drug-metabolizing cytochrome P450 (CYP) enzymes are important contributors to interindividual differences in drug metabolism leading to adverse drug reactions. Despite their extensive characterization and importance in pharmacogenetics of clinical drugs, the structural basis of CYP polymorphisms has remained scant. Here we report the crystal structures of human CYP2C9 and its polymorphic variants, *3 (I359L) and *30 (A477T), with an antihypertensive drug losartan. The structures show distinct interaction and occupation of losartan in the active site, the access channel, and the peripheral binding site. The I359L substitution located far from the active site remarkably altered the residue side chains near the active site and the access channel, whereas the T477 substitution illustrated hydrogen-bonding interaction with the reoriented side chain of Q214. The results yield structural insights into the reduced catalytic activity of the CYP2C9 variants and have important implications for understanding genetic polymorphisms in CYP-mediated drug metabolism.

Evaluation of the Potential Risk of Drugs to Induce Hepatotoxicity in Human-Relationships between Hepatic Steatosis Observed in Non-Clinical Toxicity Study and Hepatotoxicity in Humans.

In the development of drugs, we sometimes encounter fatty change of the hepatocytes (steatosis) which is not accompanied by degenerative change in the liver in non-clinical toxicity studies. In this study, we investigated the relationships between fatty change of the hepatocytes noted in non-clinical toxicity studies of compound X, a candidate compound in drug development, and mitochondrial dysfunction in order to estimate the potential risk of the compound to induce drug-induced liver injury (DILI) in humans. We conducted in vivo and in vitro exploratory studies for this purpose. In vivo lipidomics analysis was conducted to investigate the relationships between alteration of the hepatic lipids and mitochondrial dysfunction. In the liver of rats treated with compound X, triglycerides containing long-chain fatty acids, which are the main energy source of the mitochondria, accumulated. Accumulation of these triglycerides was considered to be related to the inhibition of mitochondrial respiration based on the results of in vitro mitochondria toxicity studies. In conclusion, fatty change of the hepatocytes (steatosis) in non-clinical toxicity studies of drug candidates can be regarded as a critical finding for the estimation of their potential risk to induce DILI in humans when the fatty change is induced by mitochondrial dysfunction.

Gender- and Age-Associated Differences in Serum Metabolite Profiles among Japanese Populations.

Serum metabolites can reflect the diffusion/export of biochemicals from various organs. They can serve as biomarkers related to diseases and therapeutic efficacy/toxicity. While studies in Caucasians suggested that subject gender and age can affect circulating metabolite profiles, the Japanese population has not been surveyed. Our objective was to delineate gender- and age-associated differences in serum metabolite profiles among Japanese populations. Using a mass spectrometry-based global metabolomics approach, 516 endogenous metabolites were detected in sera from Japanese individuals. The principal component analysis identified gender as the primary component, followed by age, suggesting that these two criteria were key contributors to variations in the dataset. Gender-associated differences were observed in 31 and 25% of metabolites in the young (age 25-35) and old (ages 55-65) populations, respectively, in redox homeostasis, and in steroid and purine nucleotide metabolism pathways. Age-associated differences were observed in 24 and 23% of metabolites in men and women, respectively. No pathway was commonly highlighted. Thus, gender and age impact on metabolite profiles in the Japanese population. Our results provide useful information to explore biomarkers for clinical applications in the Japanese population and to assess the applicability of known biomarkers identified in other populations to the Japanese population.

Plasma lipid profiling of different types of hepatic fibrosis induced by carbon tetrachloride and lomustine in rats.

BACKGROUND: Plasma lipid profiling has emerged as a useful tool for understanding the pathophysiology of hepatic injury and disease. Hepatic fibrosis results from chronic, progressive damage to the liver and can lead, in turn, to more serious conditions such as hepatic cirrhosis and hepatocellular carcinoma. Thus, the present study aimed to investigate the plasma lipid profiles of two types of hepatic fibrosis in order to aid the understanding of the pathophysiology of hepatic fibrosis. METHODS: A liquid chromatography and mass spectrometry platform was used to reveal and compare the plasma lipid profiles of two types of chemical-induced hepatic fibrosis. Rat models of centrilobular fibrosis and bile duct fibrosis were established via chronic exposure to the known fibrogenic hepatotoxins, carbon tetrachloride (CCl4) or lomustine (LS), respectively, over a 28-day period. To delineate the specific alterations in the lipid profiles as a result of the hepatic fibrosis, we also employed non-fibrogenic hepatotoxicants (2-acetamidofluorene, N-nitrosodiethylamine, and ethambutol) as well as 3-day treatment of CCl4 and LS, which did not induce fibrosis. RESULTS: Our assay platform identified 228 lipids in the rat plasma, and the global lipid profile clearly distinguished these models from the control via principal component analysis. In addition, the alteration of the plasma lipid profile caused by CCl4 and LS were clearly different. Furthermore, a number of lipids were identified as specific alterations caused by fibrosis induced only by CCl4 and LS, respectively. Three lysophosphatidylcholines (LPC[18:3], LPC[20:4], and LPC[22:6]), and three phosphatidylcholines (PC[18:2/20:4], PC[40:8], and PC[20:4/22:6]) are specific circulating lipids, the levels of which were altered by both CCl4 and LS treatment; however, their levels were decreased by chronic exposure to CCl4 and increased by chronic exposure to LS. CONCLUSIONS: These results suggest that different types of chemical-induced hepatic fibrosis demonstrate clear differences in their plasma lipid profiles. Our study provides insights into the alteration of plasma lipidomic profiles as a result of the fibrosis of different parts of the hepatic lobule, and may help to understand the pathophysiology of different types of hepatic fibrosis.

IKZF1, a new susceptibility gene for cold medicine-related Stevens-Johnson syndrome/toxic epidermal necrolysis with severe mucosal involvement.

BACKGROUND: Stevens-Johnson syndrome (SJS) and its severe form, toxic epidermal necrolysis (TEN), are acute inflammatory vesiculobullous reactions of the skin and mucous membranes, including the ocular surface, oral cavity, and genitals. These reactions are very rare but are often associated with inciting drugs, infectious agents, or both. OBJECTIVE: We sought to identify susceptibility loci for cold medicine-related SJS/TEN (CM-SJS/TEN) with severe mucosal involvement (SMI). METHODS: A genome-wide association study was performed in 808 Japanese subjects (117 patients with CM-SJS/TEN with SMI and 691 healthy control subjects), and subsequent replication studies were performed in 204 other Japanese subjects (16 cases and 188 control subjects), 117 Korean subjects (27 cases and 90 control subjects), 76 Indian subjects (20 cases and 56 control subjects), and 174 Brazilian subjects (39 cases and 135 control subjects). RESULTS: In addition to the most significant susceptibility region, HLA-A, we identified IKZF1, which encodes Ikaros, as a novel susceptibility gene (meta-analysis, rs4917014 [G vs. T]; odds ratio, 0.5; P = 8.5 × 10(-11)). Furthermore, quantitative ratios of the IKZF1 alternative splicing isoforms Ik1 and Ik2 were significantly associated with rs4917014 genotypes. CONCLUSION: We identified IKZF1 as a susceptibility gene for CM-SJS/TEN with SMI not only in Japanese subjects but also in Korean and Indian subjects and showed that the Ik2/Ik1 ratio might be influenced by IKZF1 single nucleotide polymorphisms, which were significantly associated with susceptibility to CM-SJS/TEN with SMI.

No contribution of the ABCB11 p.444A polymorphism in Japanese patients with drug-induced cholestasis.

European studies have revealed that the ABCB11 c.1331T>C (V444A) polymorphism (rs2287622) C-allele frequency is higher among patients with drug-induced cholestasis. Given the low incidence of this disease, however, this association has not been sufficiently elucidated. We aimed to investigate the significance of this polymorphism in Japanese patients. We determined ABCB11 V444A polymorphism frequencies and HLA genotypes in two independent drug-induced cholestasis cohorts. Expression and taurocholate transport activity of proteins from 444A variants were analyzed using Madin-Darby canine kidney II cells. In cohort 1 (n = 40), the V444A polymorphism C-allele frequency (66%) was lower than that in controls (n = 190, 78%), but this difference was not significant (P = 0.09). In cohort 2 (n = 119), comprising patients with cholestatic (n = 19), hepatocellular (n = 74), and mixed (n = 26) liver injuries, the C-allele frequency was lower among patients with cholestatic liver injury (68%) than among those with hepatocellular (75%) or mixed liver injury (83%), although this difference was not significant. In cohort 1, HLA-A*0201 was observed more frequently in patients (22%) than in controls [11%; P = 0.003; odds ratio, 2.4 (95% confidence interval, 1.4-4.0)]. Taurocholate transport activity of 444A-encoded protein was significantly lower than that of 444V-encoded protein (81% of 444V, P < 0.05) because of the reduced protein stability. In conclusion, ABCB11 444A had slightly reduced transport activity, but it did not contribute to the occurrence of drug-induced cholestasis in Japanese patients. Therefore, genetic susceptibility to acquired cholestasis may differ considerably by ethnicity.

Comparison of circulating lipid profiles between fasting humans and three animal species used in preclinical studies: mice, rats and rabbits.

BACKGROUND: Circulating lipid metabolites are associated with many physiological and biological processes in the body, and therefore could be used as biomarkers for evaluating drug efficacy and safety in preclinical studies. However, differences in circulating lipid profiles among humans and animals often used in preclinical studies have not been fully investigated. METHODS: We performed lipidomic analysis to obtain circulating lipid profiles of fasted humans (Caucasian, n = 15) and three animal species used in preclinical studies (mice [BALB/c, n = 5], rats [Sprague-Dawley, n = 5], and rabbits [New Zealand White, n = 5]) by using liquid chromatography-mass spectrometry. RESULTS: Our data showed marked differences in lipid profiles among humans and these animal species. Furthermore, we observed that the levels of many lipid metabolites, such as poly-unsaturated fatty acid-containing cholesteryl esters, ether-type phosphoglycerolipids, and sulfatides, were significantly different (p < 0.05) by more than 10-fold in these animals (depending on the animal species) from humans. CONCLUSION: Our data could be useful while extrapolating the data on the biomarker candidates identified in preclinical studies into clinical studies.

[Collaborative projects with academia for regulatory science studies on biomarkers].

Biomarkers are useful tools to be utilized as indicators/predictors of disease severity and drug responsiveness/safety, and thus are expected to promote efficient drug development and to accelerate proper use of approved drugs. Many academic achievements have been reported, but only a small number of biomarkers are used in clinical trials and drug treatments. Regulatory sciences on biomarkers for their secure development and proper qualification are necessary to facilitate their practical application. We started to collaborate with Tohoku University and Nagoya City University for sample quality, biomarker identification, evaluation of their usage, and making guidances. In this short review, scheme and progress of these projects are introduced.

Structural and biophysical analysis of cytochrome P450 2C9*14 and *27 variants in complex with losartan.

The human cytochrome P450 (CYP) 1, 2 and 3 families of enzymes are responsible for the biotransformation of a majority of the currently available pharmaceutical drugs. The highly polymorphic CYP2C9 predominantly metabolizes many drugs including anticoagulant S-warfarin, anti-hypertensive losartan, anti-diabetic tolbutamide, analgesic ibuprofen, etc. There are >80 single nucleotide changes identified in CYP2C9, many of which significantly alter the clearance of important drugs. Here we report the structural and biophysical analysis of two polymorphic variants, CYP2C9*14 (Arg125His) and CYP2C9*27 (Arg150Leu) complexed with losartan. The X-ray crystal structures of the CYP2C9*14 and *27 illustrate the binding of two losartan molecules, one in the active site near heme and another on the periphery. Both losartan molecules are bound in an identical conformation to that observed in the previously solved CYP2C9 wild-type complex, however, the number of losartan differs from the wild-type structure, which showed binding of three molecules. Additionally, isothermal titration calorimetry experiments reveal a lower binding affinity of losartan with *14 and *27 variants when compared to the wild-type. Overall, the results provide new insights into the effects of these genetic polymorphisms and suggests a possible mechanism contributing to reduced metabolic activity in patients carrying these alleles.

Quality Evaluation of Gentamicin Sulfate Reference Standards in Japanese Pharmacopoeia Using Hydrophilic Interaction Chromatography Combined With Tandem Mass Spectrometry.

BACKGROUND: Through the recent development of analytical technology, antibiotics quantification in the Japanese Pharmacopoeia (JP) has changed from traditional microbiological assays to physicochemical methods with high specificity and precision. However, for several multicomponent antibiotics without typical UV absorption, potency cannot be directly determined using instrumental methods such as high-performance liquid chromatography; therefore, traditional microbiological assays are still used. Gentamicin sulfate (GmS), which consists of three major components, C1, C1a, and C2, is such a typical antibiotic, and its antimicrobial potency continues to be assayed using microbiological methods in JP monographs. Introduction of a physicochemical assay for GmS is needed to help ensure its quality and quantity. OBJECTIVE: This study aimed to develop quality control measures for GmS that could be complementary to quantitative assays and purity tests specified in the JP. METHODS: For each gentamicin C component (C1, C2, and C1a), theoretical potencies were determined based on the quantitative relationship between purity and potency, as measured by quantitative 1H NMR and microbiological assays, respectively. Two lots of the JP reference standard (RS) were used as test samples, with the contents of each component and impurity (sisomicin and garamine) being determined using hydrophilic interaction liquid chromatography-tandem mass spectrometry (HILIC-MS/MS). RESULTS: The ratios of theoretical potency for C1, C2, and C1a were 1.00, 1.21, and 1.80, respectively. The potencies of the GmS JP RSs, which were estimated based on the contents and theoretical potency of each C component, corresponded well with those determined through microbiological assays. Marked differences in impurities (%) between the two RS lots were highlighted by quantifying sisomicin and garamine. CONCLUSIONS: The developed analytical procedure enabled the characterization of two different JP RSs in terms of content ratio, potencies, and impurities. HIGHLIGHTS: Novel analytical procedures useful for routine quality control of GmS were developed using HILIC-MS/MS.

Global metabolomic analysis of heart tissue in a hamster model for dilated cardiomyopathy.

Dilated cardiomyopathy (DCM), a common cause of heart failure, is characterized by cardiac dilation and reduced left ventricular ejection fraction, but the underlying mechanisms remain unclear. To investigate the mechanistic basis, we performed global metabolomic analysis of myocardial tissues from the left ventricles of J2N-k cardiomyopathic hamsters. This model exhibits symptoms similar to those of human DCM, owing to the deletion of the δ-sarcoglycan gene. Charged and lipid metabolites were measured by capillary electrophoresis mass spectrometry (MS) and liquid chromatography MS(/MS), respectively, and J2N-k hamsters were compared with J2N-n healthy controls at 4 (presymptomatic phase) and 16weeks (symptomatic) of age. Disturbances in membrane phospholipid homeostasis were initiated during the presymptomatic phase. Significantly different levels of charged metabolites, occurring mainly in the symptomatic phase, were mapped to primary metabolic pathways. Reduced levels of metabolites in glycolysis, the pentose phosphate pathway, and the tricarboxylic acid cycle, together with large decreases in major triacylglycerol levels, suggested that decreased energy production leads to cardiac contractile dysfunction in the symptomatic phase. A mild reduction in glutathione and a compensatory increase in ophthalmate levels suggest increased oxidative stress in diseased tissues, which was confirmed by histochemical staining. Increased levels of 4 eicosanoids, including prostaglandin (PG) E2 and 6-keto-PGF1α, in the symptomatic phase suggested activation of the protective response pathways. These results provide mechanistic insights into DCM pathogenesis and may help identify new targets for therapeutic intervention and diagnosis.

Plasma and serum from nonfasting men and women differ in their lipidomic profiles.

Biomarkers will play important roles in disease diagnosis, drug development, and the proper use of drugs. Blood is considered the best biofluid for biomarker research because it is easy to access and a wealth of data are available. However, previous studies revealed that several ionic metabolites showed different levels (including presence or absence) in plasma and serum. Thus, attention should be paid to selecting the best biofluid for biomarker exploration. Many lipid molecules have biological significance and thus would be candidate biomarkers. However, no comprehensive study revealing differences in lipid metabolite levels between plasma and serum has been undertaken. Furthermore, gender differences have not been reported. To clarify the difference in the levels of lipid metabolites between human plasma and serum from both genders, we performed lipid metabolomic analysis using liquid chromatography-mass spectrometry-based systems for phospholipids (PLs), lysoPLs, sphingomyelins, ceramides and oxidative fatty acids. Our results revealed that most of the lipid metabolites were present at similar levels in plasma and serum and in males and females. However, several oxidative fatty acid metabolites showed differences. Of the metabolites related to clotting processes, three showed higher levels in serum than in plasma, and three were detected only in serum. Furthermore, four metabolites were present at different levels between males and females, and two were detected only in males. Thus, attention should be paid to the selection of plasma or serum when utilizing these lipid metabolites as biomarkers.

Lipidomic analysis of brain tissues and plasma in a mouse model expressing mutated human amyloid precursor protein/tau for Alzheimer's disease.

BACKGROUND: Alzheimer's disease (AD), the most common cause of dementia among neurodegenerative diseases, afflicts millions of elderly people worldwide. In addition to amyloid-beta (Aß) peptide and phosphorylated tau, lipid dysregulation is suggested to participate in AD pathogenesis. However, alterations in individual lipid species and their role in AD disease progression remain unclear. METHODS: We performed a lipidomic analysis using brain tissues and plasma obtained from mice expressing mutated human amyloid precursor protein (APP) and tau protein (Tg2576×JNPL3) (APP/tau mice) at 4 (pre-symptomatic phase), 10 (early symptomatic) and 15 months (late symptomatic). RESULTS: Levels of docosahexaenoyl (22:6) cholesterol ester (ChE) were markedly increased in APP/tau mice compared to controls at all stages examined. Several species of ethanolamine plasmalogens (pPEs) and sphingomyelins (SMs) showed different levels between brains from APP/tau and control mice at various stages of AD. Increased levels of 12-hydroxyeicosatetraenoic acid (12-HETE) during the early symptomatic phase were consistent with previous reports using human AD brain tissue. In addition, 19,20-dihydroxy-docosapentaenoic acid (19,20-diHDoPE) and 17,18-dihydroxy-eicosatetraenoic acid (17,18-diHETE), which are produced from docosahexaenoic acid and eicosapentaenoic acid via 19,20-epoxy-docosapentaenoic acid (19,20-EpDPE) and 17,18-epoxy-eicosatetraenoic acid (17,18-EpETE), respectively, were significantly increased in APP/tau brains during the pre-symptomatic phase, and concomitant increases occurred in plasma. Several arachidonic acid metabolites such as prostaglandin D2 (PGD2) and 15-hydroxyeicosatetraenoic acid (15-HETE), which have potential deteriorating and protective actions, respectively, were decreased in the early symptomatic phase of APP/tau mice. Significant decreases in phosphatidylcholines and PEs with polyunsaturated fatty acids were also detected in the late symptomatic phase, indicating a perturbation of membrane properties. CONCLUSION: Our results provide fundamental information on lipid dysregulation during various stages of human AD.

NMR-based metabolomics of urine in a mouse model of Alzheimer's disease: identification of oxidative stress biomarkers.

Alzheimer's disease (AD) is the most common cause of neurodegenerative dementia among elderly patients. A biomarker for the disease could make diagnosis easier and more accurate, and accelerate drug discovery. In this study, NMR-based metabolomics analysis in conjunction with multivariate statistics was applied to examine changes in urinary metabolites in transgenic AD mice expressing mutant tau and ß-amyloid precursor protein. These mice showed significant changes in urinary metabolites throughout the progress of the disease. Levels of 3-hydroxykynurenine, homogentisate and allantoin were significantly higher compared to control mice in 4 months (prior to onset of AD symptoms) and reverted to control values by 10 months of age (early/middle stage of AD), which highlights the relevance of oxidative stress to this neurodegenerative disorder even prior the onset of dementia. The level of these changed metabolites at very early period may provide an indication of disease risk at asymptomatic stage.

[Toward acceleration of drug development with proteomic and metabolomic biomarkers].

Biomarkers, reflecting disease states or predicting/assessing drug efficacy or adverse reactions, are expected to play pivotal roles in effective drug development and promoting proper usage of drugs. To accelerate biomarker identification and usage, administrative guidance can direct to design appropriate exploration, validation and utilization studies and show examination procedures. However, very limited number of guidance or its draft were released from Japanese, US and European regulatory authorities so far. From 2012, we have been conducting proteomic and metabolomic studies using blood and urine samples from human and rat, in order to establish draft guidance for sampling/storage of these biofluid and for extrapolation of biomarker candidates from animals in the non-clinical to humans in the clinical studies. The results are still partial and the rest of the analysis is ongoing. However, we developed sensitive proteomic system for urine and found large inter-sex differences in the proteomic profiles of rat. In addition, matrix-, sex- and generation-differences were also observed in the metabolite levels in human blood, some of which showed over 2-fold differences. We continue this regulatory science studies for contribution to accelerated novel biomarker findings and its usage by generation of the draft guidance.

Validation of a genotyping technique for a surrogate marker of HLA-B∗58:01 for allopurinol-induced Stevens-Johnson syndrome and toxic epidermal necrolysis in the Japanese population.

Stevens-Johnson syndrome and toxic epidermal necrolysis (SJS/TEN) are rare but severe cutaneous adverse drug reactions. Certain human leukocyte antigen (HLA) types have been associated with SJS/TEN onset, e.g., HLA-B∗58:01 with allopurinol-induced SJS/TEN, but HLA typing is time-consuming and expensive; thus, it is not commonly used in clinical situations. In the previous work, we demonstrated that the single-nucleotide polymorphisms (SNP) rs9263726 was in absolute linkage disequilibrium with HLA-B∗58:01 in the Japanese population, and can be used as a surrogate marker for the HLA. Here, we developed a new genotyping method for the surrogate SNP using the single-stranded tag hybridization chromatographic printed-array strip (STH-PAS) technique and performed an analytical validation. The results of genotyping rs9263726 using STH-PAS correlated well with those obtained using the TaqMan SNP Genotyping Assay for 15 HLA-B∗58:01-positive and 13 HLA-B∗58:01-negative patients (analytical sensitivity and specificity were both 100%). Additionally, at least 1.11 ng of genomic DNA was sufficient to digitally and manually detect positive signals on the strip. Robustness studies showed that the annealing temperature (66 °C) was the most important condition related to reliable results. Collectively, we developed an STH-PAS method that can rapidly and easily detect rs9263726 for predicting SJS/TEN onset.