http://repub.eur.nl/res/aut/31570/ List of Publications en http://repub.eur.nl/static-eur/img/logo.png http://repub.eur.nl http://repub.eur.nl/res/pub/26309/ 2011-04-20T00:00:00Z The bioavailability of orally administered imatinib is >90%, although the drug is monocationic under the acidic conditions in the duodenum. In vitro, we found that imatinib is transported by the intestinal uptake carrier organic anion transporting polypeptide (OATP1A2) and that this process is sensitive to pH, rosuvastatin, and genetic variants. However, in a study in patients with cancer, imatinib absorption was not associated with OATP1A2 variants and was unaffected by rosuvastatin. These findings highlight the importance of verifying in a clinical setting the drug-transporter interactions observed in in vitro tests. http://repub.eur.nl/res/pub/27771/ 2010-06-10T00:00:00Z Background Vitamin D is crucial for maintenance of musculoskeletal health, and might also have a role in extraskeletal tissues. Determinants of circulating 25-hydroxyvitamin D concentrations include sun exposure and diet, but high heritability suggests that genetic factors could also play a part. We aimed to identify common genetic variants affecting vitamin D concentrations and risk of insufficiency. Methods We undertook a genome-wide association study of 25-hydroxyvitamin D concentrations in 33 996 individuals of European descent from 15 cohorts. Five epidemiological cohorts were designated as discovery cohorts (n=16 125), five as in-silico replication cohorts (n=9367), and five as de-novo replication cohorts (n=8504). 25-hydroxyvitamin D concentrations were measured by radioimmunoassay, chemiluminescent assay, ELISA, or mass spectrometry. Vitamin D insufficiency was defined as concentrations lower than 75 nmol/L or 50 nmol/L. We combined results of genome-wide analyses across cohorts using Z-score-weighted meta-analysis. Genotype scores were constructed for confirmed variants. Findings Variants at three loci reached genome-wide significance in discovery cohorts for association with 25-hydroxyvitamin D concentrations, and were confirmed in replication cohorts: 4p12 (overall p=1·9×10-109for rs2282679, in GC); 11q12 (p=2·1×10-27for rs12785878, near DHCR7); and 11p15 (p=3·3×10-20for rs10741657, near CYP2R1). Variants at an additional locus (20q13, CYP24A1) were genome-wide significant in the pooled sample (p=6·0×10-10for rs6013897). Participants with a genotype score (combining the three confirmed variants) in the highest quartile were at increased risk of having 25-hydroxyvitamin D concentrations lower than 75 nmol/L (OR 2·47, 95% CI 2·20-2·78, p= 2·3×10-48) or lower than 50 nmol/L (1·92, 1·70-2·16, p=1·0×10-26) compared with those in the lowest quartile. Interpretation Variants near genes involved in cholesterol synthesis, hydroxylation, and vitamin D transport affect vitamin D status. Genetic variation at these loci identifies individuals who have substantially raised risk of vitamin D insufficiency. Funding Full funding sources listed at end of paper (see Acknowledgments). ]. http://repub.eur.nl/res/pub/24576/ 2009-06-01T00:00:00Z Chronic kidney disease (CKD) has a heritable component and is an important global public health problem because of its high prevalence and morbidity. We conducted genome-wide association studies (GWAS) to identify susceptibility loci for glomerular filtration rate, estimated by serum creatinine (eGFRcrea) and cystatin C (eGFRcys), and CKD (eGFRcrea 60 ml/min/1.73 m 2) in European-ancestry participants of four population-based cohorts (ARIC, CHS, FHS, RS; n = 19,877; 2,388 CKD cases), and tested for replication in 21,466 participants (1,932 CKD cases). We identified significant SNP associations (P 5 × 10 8) with CKD at the UMOD locus, with eGFRcrea at UMOD, SHROOM3 and GATM-SPATA5L1, and with eGFRcys at CST and STC1. UMOD encodes the most common protein in human urine, Tamm-Horsfall protein, and rare mutations in UMOD cause mendelian forms of kidney disease. Our findings provide new insights into CKD pathogenesis and underscore the importance of common genetic variants influencing renal function and disease.