UNLABELLED: P-glycoprotein (P-gp) is a membrane protein that functions as an adenosine triphosphate-dependent efflux pump for xenobiotics at the blood-brain barrier (BBB). Polymorphisms of MDR1 gene have been reported to be associated with the expression level of P-gp. (11)C-Verapamil is considered to be one of the suitable radioligands for evaluating P-gp functions. However, the metabolites of verapamil might complicate the quantitative analysis because of their possible brain penetration. In the present study, we investigated the P-gp functional differences at the BBB between the haplotypes (1236TT, 2677TT, 3435TT vs. 1236CC, 2677GG, 3435CC) of the MDR1 gene with different quantitative analyses of (11)C-verapamil. METHODS: Thirty-three healthy male volunteers were enrolled in this study after identification of the haplotypes of the MDR1 gene. Brain PET scans with (11)C-verapamil were performed for 16 min. Integration plot analysis, which yields brain uptake clearance, was performed with the first 3-min data. Integration plot analysis was then compared with several other quantitative analyses with 16-min data (1-input, 1-tissue compartment model, and the area under the curve ratio (AUC(ratio)) between brain and plasma). RESULTS: In the integration plot, there was no difference in the absolute values of brain uptake clearance (CL(uptake)) between the haplotypes; CL(uptake) of (11)C-verapamil for the haplotypes (1236TT, 2677TT, 3435TT vs. 1236CC, 2677GG, 3435CC) were 0.053 +/- 0.011 and 0.051 +/- 0.011 mL/g/min, respectively. CL(uptake) of (11)C-verapamil in the integration plot was significantly correlated with K1 and DV(K1/k2) (DV is distribution volume; K1 and k2 are plasma and tissue rate constants) in the 1-input, 1-tissue compartment model and the AUC(ratio). CONCLUSION: On the basis of the several quantitative analyses of (11)C-verapamil, the assumption that the function of P-gp at the BBB is different between the haplotypes (3 single nucleotide polymorphisms: C1236T, G2677T, and C3435T) of MDR1 gene was not supported.
UNLABELLED: P-glycoprotein (P-gp) is a membrane protein that functions as an adenosine triphosphate-dependent efflux pump for xenobiotics at the blood-brain barrier (BBB). Polymorphisms of MDR1 gene have been reported to be associated with the expression level of P-gp. (11)C-Verapamil is considered to be one of the suitable radioligands for evaluating P-gp functions. However, the metabolites of verapamil might complicate the quantitative analysis because of their possible brain penetration. In the present study, we investigated the P-gp functional differences at the BBB between the haplotypes (1236TT, 2677TT, 3435TT vs. 1236CC, 2677GG, 3435CC) of the MDR1 gene with different quantitative analyses of (11)C-verapamil. METHODS: Thirty-three healthy male volunteers were enrolled in this study after identification of the haplotypes of the MDR1 gene. Brain PET scans with (11)C-verapamil were performed for 16 min. Integration plot analysis, which yields brain uptake clearance, was performed with the first 3-min data. Integration plot analysis was then compared with several other quantitative analyses with 16-min data (1-input, 1-tissue compartment model, and the area under the curve ratio (AUC(ratio)) between brain and plasma). RESULTS: In the integration plot, there was no difference in the absolute values of brain uptake clearance (CL(uptake)) between the haplotypes; CL(uptake) of (11)C-verapamil for the haplotypes (1236TT, 2677TT, 3435TT vs. 1236CC, 2677GG, 3435CC) were 0.053 +/- 0.011 and 0.051 +/- 0.011 mL/g/min, respectively. CL(uptake) of (11)C-verapamil in the integration plot was significantly correlated with K1 and DV(K1/k2) (DV is distribution volume; K1 and k2 are plasma and tissue rate constants) in the 1-input, 1-tissue compartment model and the AUC(ratio). CONCLUSION: On the basis of the several quantitative analyses of (11)C-verapamil, the assumption that the function of P-gp at the BBB is different between the haplotypes (3 single nucleotide polymorphisms: C1236T, G2677T, and C3435T) of MDR1 gene was not supported.
Authors: William C Kreisl; Jeih-San Liow; Nobuyo Kimura; Nicholas Seneca; Sami S Zoghbi; Cheryl L Morse; Peter Herscovitch; Victor W Pike; Robert B Innis Journal: J Nucl Med Date: 2010-03-17 Impact factor: 10.057
Authors: Kathleen M Giacomini; Shiew-Mei Huang; Donald J Tweedie; Leslie Z Benet; Kim L R Brouwer; Xiaoyan Chu; Amber Dahlin; Raymond Evers; Volker Fischer; Kathleen M Hillgren; Keith A Hoffmaster; Toshihisa Ishikawa; Dietrich Keppler; Richard B Kim; Caroline A Lee; Mikko Niemi; Joseph W Polli; Yuichi Sugiyama; Peter W Swaan; Joseph A Ware; Stephen H Wright; Sook Wah Yee; Maciej J Zamek-Gliszczynski; Lei Zhang Journal: Nat Rev Drug Discov Date: 2010-03 Impact factor: 84.694
Authors: P Blanckaert; I Burvenich; S Staelens; S De Bruyne; L Moerman; L Wyffels; F De Vos Journal: Eur J Nucl Med Mol Imaging Date: 2008-11-05 Impact factor: 9.236
Authors: P Kannan; C John; S S Zoghbi; C Halldin; M M Gottesman; R B Innis; M D Hall Journal: Clin Pharmacol Ther Date: 2009-07-22 Impact factor: 6.875
Authors: Neva Lazarova; Sami S Zoghbi; Jinsoo Hong; Nicholas Seneca; Ed Tuan; Robert L Gladding; Jeih-San Liow; Andrew Taku; Robert B Innis; Victor W Pike Journal: J Med Chem Date: 2008-09-11 Impact factor: 7.446
Authors: Jeih-San Liow; William Kreisl; Sami S Zoghbi; Neva Lazarova; Nicholas Seneca; Robert L Gladding; Andrew Taku; Peter Herscovitch; Victor W Pike; Robert B Innis Journal: J Nucl Med Date: 2008-12-17 Impact factor: 10.057