[Show abstract][Hide abstract] ABSTRACT: The incidence of acid-base disorders (ABDs) is high, especially in hospitalized patients. ABDs are often indicators for severe systemic disorders. In everyday clinical practice, analysis of ABDs must be performed in a standardized manner. Highly sensitive diagnostic tools to distinguish the various ABDs include the anion gap and the serum osmolar gap. Drug-induced ABDs can be classified into five different categories in terms of their pathophysiology: (1) metabolic acidosis caused by acid overload, which may occur through accumulation of acids by endogenous (e.g., lactic acidosis by biguanides, propofol-related syndrome) or exogenous (e.g., glycol-dependant drugs, such as diazepam or salicylates) mechanisms or by decreased renal acid excretion (e.g., distal renal tubular acidosis by amphotericin B, nonsteroidal anti-inflammatory drugs, vitamin D); (2) base loss: proximal renal tubular acidosis by drugs (e.g., ifosfamide, aminoglycosides, carbonic anhydrase inhibitors, antiretrovirals, oxaliplatin or cisplatin) in the context of Fanconi syndrome; (3) alkalosis resulting from acid and/or chloride loss by renal (e.g., diuretics, penicillins, aminoglycosides) or extrarenal (e.g., laxative drugs) mechanisms; (4) exogenous bicarbonate loads: milk-alkali syndrome, overshoot alkalosis after bicarbonate therapy or citrate administration; and (5) respiratory acidosis or alkalosis resulting from drug-induced depression of the respiratory center or neuromuscular impairment (e.g., anesthetics, sedatives) or hyperventilation (e.g., salicylates, epinephrine, nicotine).
[Show abstract][Hide abstract] ABSTRACT: At present the global diabetes epidemic is affecting 347 million individuals, 90% of whom are diagnosed with type II diabetes mellitus (T2DM). T2DM is commonly treated with more than one type of therapy, including oral antidiabetic drugs (OADs) and agents used in the treatment of diabetic complications. Several pharmacological classes of OADs are currently available for the treatment of T2DM, of which insulin secretagogues (i.e. sulphonylureas and meglitinides), insulin sensitizers (thiazolidinediones) and biguanides are the most commonly prescribed. Although many of these OADs have been used for more than half a century in the treatment of T2DM, the pharmacogenomic characteristics of these compounds have only recently been investigated, primarily in retrospective studies. Recent advances in pharmacogenomics have led to the identification of polymorphisms that affect the expression and function of drug-metabolizing enzymes and drug transporters, as well as drug targets and receptors. These polymorphisms have been shown to affect the therapeutic response to and side effects associated with OADs. The aim of this review was to provide an up-to-date summary of some of the pharmacogenomic data obtained from studies of T2DM treatment, with a focus on polymorphisms in genes affecting pharmacokinetics, pharmacodynamics and treatment outcome of the most commonly prescribed OADs. In addition, the implications of pharmacogenomics in the use of the OAD metformin in cancer will be briefly discussed. Finally, we will focus on recent advances in novel ‘omics’ technologies and discuss how these might aid in the personalized management of T2DM.This article is protected by copyright. All rights reserved.
Journal of Internal Medicine 11/2014; · 6.46 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Puumala virus (PUUV) is the most common species of hantavirus in Central Europe. Nephropathia epidemica (NE), caused by PUUV, is characterized by acute kidney injury (AKI) and thrombocytopenia. The major goals of this study were to provide a clear clinical phenotyping of AKI in patients with NE and to develop an easy prediction rule to identify patients, who are at lower risk to develop severe AKI.
[Show abstract][Hide abstract] ABSTRACT: Malaria patients are frequently co-infected with HIV and mycobacteria causing tuberculosis, which increases the co-administration of drugs and thereby enhances the risk of pharmacokinetic drug-drug interactions. Activation of pregnane X receptor (PXR) by xenobiotics, including many drugs, induces drug metabolism and transport, thereby possibly resulting in attenuation or loss of the therapeutic response of drugs being co-administered. While several artemisinin-type antimalarial drugs have been shown to activate PXR, data on non-artemisinin-type antimalarials are still missing. Therefore this study aims to elucidate the potential of non-artemisinin antimalarial drugs and drug metabolites to activate PXR. The screening of 16 clinically used antimalarial drugs and six major drug metabolites for binding to PXR, using the two-hybrid PXR ligand binding domain assembly assay, identified carboxymefloquine, the major and pharmacological inactive metabolite of the antimalarial drug mefloquine, as a potential PXR ligand. Two-hybrid PXR-coactivator and -corepressor interaction assays, as well as PXR-dependent promoter reporter gene assays, confirmed carboxymefloquine as a novel PXR agonist, which specifically activated the human receptor. In the PXR-expressing intestinal LS174T cells and in primary human hepatocytes, carboxymefloquine induced the expression of drug metabolizing enzymes and transporters on the mRNA and protein level. The crucial role of PXR for carboxymefloquine-dependent induction of gene expression was confirmed by siRNA-mediated knock-down of the receptor. Thus, the clinical use of mefloquine may result in pharmacokinetic drug-drug interactions by means of its metabolite carboxymefloquine. Whether these in vitro finding are of in vivo relevance has to be addressed in future clinical drug-drug interaction studies.
Antimicrobial Agents and Chemotherapy 10/2014; · 4.57 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: In view of the rapid preclinical development of cell-based therapies for neurodegenerative disorders, traumatic brain injury, and tumors, the safe and efficient delivery and targeting of therapeutic cells to the central nervous system is critical for maintaining therapeutic efficacy and safety in the respective disease models. Our previous data demonstrated therapeutically efficacious and targeted delivery of mesenchymal stem cells (MSCs) to the brain in the rat 6-hydroxydopamine model of Parkinson?s disease (PD). The present study examined delivery of bone marrow derived MSCs, macrophages, and microglia to the brain in a transgenic model of PD ((Thy1)-h[A30P] αS) and an APP/PS1 model of Alzheimer?s disease (AD) via intranasal application (INA). INA of microglia in na?ve BL/6 mice led to targeted and effective delivery of cells to the brain. Quantitative PCR analysis of eGFP DNA showed that the brain contained the highest amount of eGFP-microglia (up to 2.1x10(4)) after INA of 1x10(6) cells, while the total amount of cells detected in peripheral organs did not exceed 3.4x10(3). Seven days after INA, MSCs expressing eGFP were detected in the olfactory bulb (OB), cortex, amygdala, striatum, hippocampus, cerebellum, and brainstem of (Thy1)-h[A30P] αS transgenic mice, showing predominant distribution within the OB and brainstem. INA of eGFP-expressing macrophages in 13 month-old APP/PS1 mice led to delivery of cells to the OB, hippocampus, cortex, and cerebellum. Both, MSCs and macrophages contained Iba-1-positive population of small microglia-like cells and Iba-1-negative large rounded cells showing either intracellular Amyloid beta (macrophages in APP/PS1 model) or α-Synuclein (MSCs in (Thy1)-h[A30P] αS model) immunoreactivity. Here we show, for the first time, intranasal delivery of cells to the brain of transgenic PD and AD mouse models. Additional work is needed to determine the optimal dosage (single treatment regimen or repeated administrations) to achieve functional improvement in these mouse models with intranasal microglia/macrophages and MSCs. This manuscript is published as part of the International Association of Neurorestoratology (IANR) special issue of Cell Transplantation.
[Show abstract][Hide abstract] ABSTRACT: Treatment of diabetics with metformin is associated with decreased breast cancer risk in observational studies, but it remains unclear if this drug has clinical antineoplastic activity. In a recent presurgical trial, we found a heterogeneous effect of metformin on breast cancer proliferation (ki-67) depending upon insulin resistance (HOMA index). Here, we determined the associations of additional serum biomarkers of insulin resistance, tumor subtype, and drug concentration with ki-67 response to metformin. Two-hundred non-diabetic women were randomly allocated to metformin (850 mg/bid) or placebo for 4 weeks prior to breast cancer surgery. The ki-67 response to metformin was assessed comparing data obtained from baseline biopsy (ki-67 and tumor subtype) and serum markers (HOMA index, C-peptide, IGF-I, IGFBP-1, IGFBP-3, free IGF-I, hs-CRP, adiponectin) with the same measurements at definitive surgery. For patients with a blood sample taken within 24 h from last drug intake, metformin level was measured. Compared with placebo, metformin significantly decreased ki-67 in women with HOMA > 2.8, those in the lowest IGFBP-1 quintile, those in the highest IGFBP-3 quartile, those with low free IGF-I, those in the top hs-CRP tertile, and those with HER2-positive tumors. In women with HOMA index > 2.8, drug levels were positively correlated with the ki-67 decrease, whereas no trend was noted in women with HOMA < 2.8 (p-interaction = 0.07). At conventional antidiabetic doses, the effect of metformin on tumor ki-67 of non-diabetic breast cancer patients varies with host and tumor characteristics. These findings are relevant to design breast cancer prevention and treatment trials with metformin.
Breast Cancer Research and Treatment 09/2014; · 4.47 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Targeted chemotherapy for hepatocellular carcinoma (HCC) is impaired by intrinsic and/or acquired drug resistance. Since drugs used in HCC therapy (e.g. anthracyclines or the tyrosine kinase inhibitor sorafenib) are substrates of uptake and/or efflux transporters, variable expression of these transporters at the plasma membrane of tumor cells may contribute to drug resistance and subsequent clinical response. In this study, the variability of expression of uptake (OCT1, OCT3) and efflux transporters (MDR1/P-glycoprotein, MRP1, MRP2, BCRP), selected for their implication in transporting drugs used in HCC therapy, was investigated. HCC and corresponding non-tumor tissue samples were collected from 24 Japanese patients at time of surgery. Protein expression was determined by immunohistochemistry. Expression data were correlated with clinicopathological characteristics and patients' outcome (median follow-up 53 months). Generally, expression was highly variable among individual tumor samples. Yet, median expression of OCT1, OCT3 and MDR1 in HCC was significantly lower (1.4-, 2.7- and 2-fold, respectively) than in non-tumor tissue, while expression of MRP2 persisted and BCRP showed a trend of increased levels in HCC. Patients with low BCRP expression had a significantly shorter overall and recurrence-free survival time. Results suggest different expression patterns of drug transporters in HCC, which are only in part associated with clinicopathological characteristics. Detailed information of expression of drug transporters in HCC may be promising for individualization and optimization of drug therapy of liver cancer.
Drug metabolism and disposition: the biological fate of chemicals 09/2014; · 3.74 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: In addition to its well-characterized role in the regulation of drug metabolism and transport by xenobiotics, pregnane X receptor (PXR) critically impacts on lipid homeostasis. In mice, both ligand-dependent activation and knockout of PXR were previously shown to promote hepatic steatosis. To elucidate the respective pathways in human liver, we generated clones of human hepatoma HepG2 cells exhibiting different PXR protein levels, and analyzed effects of PXR activation and knockdown on steatosis and expression of lipogenic genes. Ligand-dependent activation as well as knockdown of PXR resulted in increased steatosis in HepG2 cells. Activation of PXR induced the sterol regulatory element-binding protein (SREBP) 1-dependent lipogenic pathway via PXR-dependent induction of SREBP1a, which was confirmed in primary human hepatocytes. Inhibiting SREBP1 activity by blocking the cleavage-dependent maturation of SREBP1 protein impaired the induction of lipogenic SREBP1 target genes and triglyceride accumulation by PXR activation. On the other hand, PXR knockdown resulted in up-regulation of aldo-keto reductase (AKR) 1B10, which enhanced the acetyl-CoA carboxylase (ACC)-catalyzed reaction step of de novo lipogenesis. In a cohort of human liver samples histologically classified for non-alcoholic fatty liver disease, AKR1B10, SREBP1a and SREBP1 lipogenic target genes proved to be up-regulated in steatohepatitis, while PXR protein was reduced. In summary, our data suggest that activation and knockdown of PXR in human hepatic cells promote de novo lipogenesis and steatosis by induction of the SREBP1 pathway and AKR1B10-mediated increase of ACC activity, respectively, thus providing mechanistic explanations for a putative dual role of PXR in the pathogenesis of steatohepatitis.
[Show abstract][Hide abstract] ABSTRACT: Tamoxifen is the standard-of-care treatment for estrogen receptor-positive premenopausal breast cancer. We examined tamoxifen metabolism via blood metabolite concentrations and germline variations of CYP3A5, CYP2C9, CYP2C19 and CYP2D6 in 587 premenopausal patients (Asians, Middle Eastern Arabs, Caucasian-UK; median age 39 years) and clinical outcome in 306 patients. N-desmethyltamoxifen (DM-Tam)/(Z)-endoxifen and CYP2D6 phenotype significantly correlated across ethnicities (R(2): 53%, P<10(-77)). CYP2C19 and CYP2C9 correlated with norendoxifen and (Z)-4-hydroxytamoxifen concentrations, respectively (P<0.001). DM-Tam was influenced by body mass index (P<0.001). Improved distant relapse-free survival (DRFS) was associated with decreasing DM-Tam/(Z)-endoxifen (P=0.036) and increasing CYP2D6 activity score (hazard ratio (HR)=0.62; 95% confidence interval (CI), 0.43-0.91; P=0.013). Low (<14 nM) compared with high (>35 nM) endoxifen concentrations were associated with shorter DRFS (univariate P=0.03; multivariate HR=1.94; 95% CI, 1.04-4.14; P=0.064). Our data indicate that endoxifen formation in premenopausal women depends on CYP2D6 irrespective of ethnicity. Low endoxifen concentration/formation and decreased CYP2D6 activity predict shorter DRFS.The Pharmacogenomics Journal advance online publication, 5 August 2014; doi:10.1038/tpj.2014.34.
[Show abstract][Hide abstract] ABSTRACT: Wnt signaling regulates small intestinal stem cell maintenance and Paneth cell differentiation. In patients with ileal Crohn's disease (CD) a decrease of Paneth cell α-defensins has been observed which is partially caused by impaired TCF-4 and LRP6 function. Here we show reduced expression of the Wnt signaling effector TCF-1 (also known as TCF7) in patients with ileal CD. Reporter gene assays and in vitro promoter binding analysis revealed that TCF-1 activates α-defensin HD-5 and HD-6 transcription in cooperation with β-catenin and that activation is mediated by three distinct TCF binding sites. EMSA analysis showed binding of TCF-1 to the respective motifs. In ileal CD patients, TCF-1 mRNA expression levels were significantly reduced. Moreover we found specifically reduced expression of active TCF-1 mRNA isoforms. Tcf-1 knockout mice exhibited reduced cryptdin expression in the jejunum, which was not constistently seen at other small intestinal locations. Our data provide evidence that TCF-1 mediated Wnt signaling is disturbed in small intestinal Crohn's disease which might contribute to the observed barrier dysfunction in the disease.
American journal of physiology. Gastrointestinal and liver physiology. 07/2014;
[Show abstract][Hide abstract] ABSTRACT: Background: The well-characterized tubular-type of breast tumors is classified as low-risk breast cancer. Patients and Methods: We report on the results of a retrospective analysis on clinical and biological features of 248 tubular breast tumors including follow-up and treatment data from two German series of 21,065 breast cancer cases. The majority of tumors were stage I or stage II, ER- and PR-positive and c-erbB2-negative with a 5-year survival-rate of 96.3%. 51.3% of patients received hormonal treatment, 75.5% had post-operative radiotherapy and 11.8% were treated with a chemotherapeutical regimen. Conclusion: Our retrospective analysis showed no treatment benefit for either anti-hormonal or chemotherapeutical regimens. Post-operative radiotherapy, however, improved the survival rate of patients with tubular carcinoma (log-rank=5, p=0.025). Our data suggest that post-operative radiotherapy is an important treatment to prolong survival for patients suffering from tubular breast cancer.
Anticancer research 07/2014; 34(7):3647-56. · 1.71 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Individualized Medicine aims at providing optimal treatment for an individual patient at a given time based on his specific genetic and molecular characteristics. This requires excellent clinical stratification of patients as well as the availability of genomic data and biomarkers as prerequisites for the development of novel diagnostic tools and therapeutic strategies. The University Medicine Greifswald, Germany, has launched the "Greifswald Approach to Individualized Medicine" (GANI_MED) project to address major challenges of Individualized Medicine. Herein, we describe the implementation of the scientific and clinical infrastructure that allows future translation of findings relevant to Individualized Medicine into clinical practice.Methods/design: Clinical patient cohorts (N > 5,000) with an emphasis on metabolic and cardiovascular diseases are being established following a standardized protocol for the assessment of medical history, laboratory biomarkers, and the collection of various biosamples for bio-banking purposes. A multi-omics based biomarker assessment including genome-wide genotyping, transcriptome, metabolome, and proteome analyses complements the multi-level approach of GANI_MED. Comparisons with the general background population as characterized by our Study of Health in Pomerania (SHIP) are performed. A central data management structure has been implemented to capture and integrate all relevant clinical data for research purposes. Ethical research projects on informed consent procedures, reporting of incidental findings, and economic evaluations were launched in parallel.
Journal of translational medicine. 05/2014; 12(1):144.
[Show abstract][Hide abstract] ABSTRACT: Background: Artesunate (AS) is a water soluble hemi-succinate derivative of artemisinin, which can easily be used in formulations for parenteral treatment of severe malaria. AS is rapidly hydrolysed in vivo to the active metabolite dihydroartemisinin (DHA) and primarily eliminated into bile after glucuronidation. Very recently, delayed hemolytic anemia has been observed as a relatively frequent complication after treatment of severe malaria with AS. It has been suggested that interindividual variability in pharmacokinetic profiles of antimalarial drugs might be responsible for variations in drug response or toxicity. While CYP2A6 was identified as responsible isoenzyme for AS hydrolysis, glucuronidation is catalysed predominately by the uridine diphosphate (UDP)-glucuronosyltransferases (UGT) UGT1A9 and UGT2B7 showing both a broad range of genetic variants. To elucidate systematically the impact of AS metabolism and pharmacokinetics on drug response and adverse effects the plasma concentrations of the parent drug and its two metabolites have to be determined.
Methods: We established a novel LC-MS/MS method for simultaneous quantification of AS and its metabolites DHA and DHA glucuronide (DHAG) in human plasma. Sample preparation was performed with only 50 µL plasma by high-throughput solid phase extraction (SPE) in the 96-well plate format. Separation of the analytes was achieved on a Poroshell 120 EC-C18 column (Agilent Technologies, Waldbronn, Germany 50*2.1 mm, 2.7 µm). We used stable isotope-labelled analogues as internal standards. The method was validated according to the FDA guidelines.
Results: The method was accurate and precise within a linear calibration range from 1 to 2,500 nM, 165 to 16,500 nM and 4 to 10,000 nM for AS, DHA and DHAG, respectively. Furthermore the method passed the tests on analyte stability during bench-top and autosampler storage, after 3 freeze/thaw cycles and during long term storage. The method was applied to plasma samples from patients under AS treatment.
Conclusion: Our novel LC-MS/MS method provides a validated and highly sensitive tool for the simultaneous quantification of AS, DHA and DHAG in plasma samples. The required sample volume could be kept very low (50 µL). Using the SPE 96-well plate format permits preparation of 100 samples in only 2 h to minimize possible degradation of AS and DHA and qualifies this method to monitor pharmacokinetics and bioequivalence of large patients cohorts.
Supported by the Robert Bosch Foundation (Stuttgart, Germany), the European and Developing Countries Clinical Trials Partnership (EDCTP) grant #2004.01.M.d2, the BMBF (Germany) grant 01KA1011, the Deutsche Forschungsgemeinschaft (Germany) grant KE 1629/1-1, and the IZEPHA grant 10-0-0.
20th International Symposium on Microsomes and Drug Oxidations, Stuttgart; 05/2014
[Show abstract][Hide abstract] ABSTRACT: Only limited data exist about the role of point of care CYP2C19 testing in the acute setting in the early phase of acute coronary syndromes (ACS). Therefore, the present study was designed to investigate the impact of CYP2C19 loss-of-function point-of-care (POC) genotyping in patients presenting with acute coronary syndromes (ACS) and treated with dual antiplatelet therapy in the emergency setting.
[Show abstract][Hide abstract] ABSTRACT: Artesunate (AS), a hemisuccinate derivative of artemisinin, is readily soluble in water and can easily be used in formulations for parenteral treatment of severe malaria. AS is rapidly hydrolyzed to the active metabolite dihydroartemisinin (DHA) and primarily eliminated by biliary excretion after glucuronidation. To investigate systematically the AS metabolism and pharmacokinetics, a novel liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the simultaneous quantification of AS and its metabolites DHA and DHA glucuronide (DHAG) in human plasma samples was developed. Compared to previous methods, our method includes for the first time the quantification of the glucuronide metabolite using a newly synthesized stable isotope-labeled analogue as internal standard. Sample preparation was performed with only 50 μL plasma by high-throughput solid-phase extraction in the 96-well plate format. Separation of the analytes was achieved on a Poroshell 120 EC-C18 column (50*2.1 mm, 2.7 μm, Agilent Technologies, Waldbronn, Germany). The method was validated according to FDA guidelines. Calibration curves were linear over the entire range from 1 to 2,500 nM (0.4-961.1 ng/mL), 165 to 16,500 nM (46.9-4,691.8 ng/mL), and 4 to 10,000 nM (1.8-4,604.7 ng/mL) for AS, DHA, and DHAG, respectively. Intra- and interbatch accuracy, determined as a deviation between nominal and measured values, ranged from -5.7 to 3.5 % and from 2.7 to 5.8 %, respectively. The assay variability ranged from 1.5 to 10.9 % for intra- and interbatch approaches. All analytes showed extraction recoveries above 85 %. The method was successfully applied to plasma samples from patients under AS treatment.
Analytical and Bioanalytical Chemistry 04/2014; · 3.66 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Fluourouracil (FU) is a mainstay of chemotherapy, although toxicities are common. Genetic biomarkers have been used to predict these adverse events, but their utility is uncertain.
We tested candidate polymorphisms identified from a systematic literature search for associations with capecitabine toxicity in 927 patients with colorectal cancer in the Quick and Simple and Reliable trial (QUASAR2). We then performed meta-analysis of QUASAR2 and 16 published studies (n = 4,855 patients) to examine the polymorphisms in various FU monotherapy and combination therapy regimens.
Global capecitabine toxicity (grades 0/1/2 v grades 3/4/5) was associated with the rare, functional DPYD alleles 2846T>A and *2A (combined odds ratio, 5.51; P = .0013) and with the common TYMS polymorphisms 5`VNTR2R/3R and 3`UTR 6bp ins-del (combined odds ratio, 1.31; P = 9.4 × 10(-6)). There was weaker evidence that these polymorphisms predict toxicity from bolus and infusional FU monotherapy. No good evidence of association with toxicity was found for the remaining polymorphisms, including several currently included in predictive kits. No polymorphisms were associated with toxicity in combination regimens.
A panel of genetic biomarkers for capecitabine monotherapy toxicity would currently comprise only the four DPYD and TYMS variants above. We estimate this test could provide 26% sensitivity, 86% specificity, and 49% positive predictive value-better than most available commercial kits, but suboptimal for clinical use. The test panel might be extended to include additional, rare DPYD variants functionally equivalent to *2A and 2846A, though insufficient evidence supports its use in bolus, infusional, or combination FU. There remains a need to identify further markers of FU toxicity for all regimens.
Journal of Clinical Oncology 04/2014; 32(10):1031-9. · 18.04 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The identification of valid biomarkers for outcome prediction of diseases and improvement of drug response, as well as avoidance of side effects is an emerging field of interest in medicine. The concept of individualized therapy is becoming increasingly important in the treatment of patients with epilepsy, as predictive markers for disease prognosis and treatment outcome are still limited. Currently, the clinical decision process for selection of an antiepileptic drug (AED) is predominately based on the patient's epileptic syndrome and side effect profiles of the AEDs, but not on effectiveness data. Although standard dosages of AEDs are used, supplemented, in part, by therapeutic monitoring, the response of an individual patient to a specific AED is generally unpredictable, and the standard care of patients in antiepileptic treatment is more or less based on trial and error. Therefore, there is an urgent need for valid predictive biomarkers to guide patient-tailored individualized treatment strategies in epilepsy, a research area that is still in its infancy. This review focuses on genomic factors as part of an individual concept for AED therapy summarizing examples that influence the prognosis of the disease and the response to AEDs, including side effects.
Journal of the American Society for Experimental NeuroTherapeutics 02/2014; · 5.38 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Statin-associated muscular adverse effects cover a wide range of symptoms, including asymptomatic increase of creatine kinase serum activity and life-threatening rhabdomyolysis. Different underlying pathomechanisms have been proposed. However, a unifying concept of the pathogenesis of statin-related muscular adverse effects has not emerged so far. In this review, we attempt to categorise these mechanisms along three levels. Firstly, among pharmacokinetic factors, it has been shown for some statins that inhibition of cytochrome P450-mediated hepatic biotransformation and hepatic uptake by transporter proteins contribute to an increase of systemic statin concentrations. Secondly, at the myocyte membrane level, cell membrane uptake transporters affect intracellular statin concentrations. Thirdly, at the intracellular level, inhibition of the 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase results in decreased intracellular levels of downstream metabolites (e.g. selenoproteins, ubiquinone, cholesterol) and alteration of gene expression (e.g. ryanodine receptor 3, glycine amidinotransferase). We also review current recommendations for prescribers.
British Journal of Clinical Pharmacology 02/2014; · 3.69 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The approved dual-color fluorescence in situ hybridization (FISH) test for the detection of anaplastic lymphoma receptor tyrosine kinase (ALK) gene rearrangements in non-small-cell lung cancer (NSCLC) is complex and represents a low-throughput assay difficult to use in daily diagnostic practice. We devised a sensitive and robust routine diagnostic test for the detection of rearrangements and transcriptional up-regulation of ALK.
We developed a quantitative reverse transcription polymerase chain reaction (qRT-PCR) assay adapted to RNA isolated from routine formalin-fixed, paraffin-embedded material and applied it to 652 NSCLC specimens. The reliability of this technique to detect ALK dysregulation was shown by comparison with FISH and immunohistochemistry.
qRT-PCR analysis detected unbalanced ALK expression indicative of a gene rearrangement in 24 (4.6%) and full-length ALK transcript expression in six (1.1%) of 523 interpretable tumors. Among 182 tumors simultaneously analyzed by FISH and qRT-PCR, the latter accurately typed 97% of 19 rearranged and 158 nonrearranged tumors and identified ALK deregulation in two cases with insufficient FISH. Six tumors expressing full-length ALK transcripts did not show rearrangements of the gene. Immunohistochemistry detected ALK protein overexpression in tumors with gene fusions and transcriptional up-regulation, but did not distinguish between the two. One case with full-length ALK expression carried a heterozygous point mutation (S1220Y) within the kinase domain potentially interfering with kinase activity and/or inhibitor binding.
Our qRT-PCR assay reliably identifies and distinguishes ALK rearrangements and full-length transcript expression in formalin-fixed, paraffin-embedded material. It is an easy-to-perform, cost-effective, and high-throughput tool for the diagnosis of ALK activation. The expression of full-length ALK transcripts may be relevant for ALK inhibitor therapy in NSCLC.
Journal of thoracic oncology: official publication of the International Association for the Study of Lung Cancer 02/2014; · 4.55 Impact Factor