Influence de l'inflammation sur le métabolisme catalysé par les cytochromes P450 chez le rat : approches in vitro et implications sur la pharmacocinétique d'agonistes delta

Thèse numérisée par la Direction des bibliothèques de l'Université de Montréal

Evaluation of P-glycoprotein expression in pain relevant tissues: understanding translation of efflux from preclinical species to human

Various efflux transporters, such as P-glycoprotein (P-gp) are now widely accepted to have profound influence on the disposition of substrates. Nevertheless, there is paucity of information about their expression and functionality in the pain relevant tissues (such as brain, spinal cord and dorsal root ganglia (DRG)) across various species. Therefore, our attempts were directed at evaluating P-gp expression in these tissues to understand its effect on the central nervous system (CNS) disposition. As a means of characterizing the normal tissue distribution of P-gp, immunohistochemistry was performed with two antibodies (C219 and H241) directed against different epitopes of MDR1 gene. Notable expression of P-gp was detected in the DRG of Sprague Dawley rat, Beagle Dog, Cynomolgous monkey as well as human. The expression of P-gp was observed in the CNS tissues with evident species differences, the expression of P-gp in human brain and spinal cord was lower than in rats and dogs but relatively comparable to that in monkeys. However, no species related differences were seen in the expression at the DRG level. Double-labelling using an antibody against a marker of endothelial cells confirmed that P-gp was exclusively localized in capillary endothelial cells. This study highlights the cross species similarities and differences in the expression of P-gp and thus serves as a vital step in understanding the translation of exposure of P-gp substrates to human

Evaluation of P-glycoprotein expression in pain relevant tissues: understanding translation of efflux from preclinical species to human

Various efflux transporters, such as P-glycoprotein (P-gp) are now widely accepted to have profound influence on the disposition of substrates. Nevertheless, there is paucity of information about their expression and functionality in the pain relevant tissues (such as brain, spinal cord and dorsal root ganglia (DRG)) across various species. Therefore, our attempts were directed at evaluating P-gp expression in these tissues to understand its effect on the central nervous system (CNS) disposition. As a means of characterizing the normal tissue distribution of P-gp, immunohistochemistry was performed with two antibodies (C219 and H241) directed against different epitopes of MDR1 gene. Notable expression of P-gp was detected in the DRG of Sprague Dawley rat, Beagle Dog, Cynomolgous monkey as well as human. The expression of P-gp was observed in the CNS tissues with evident species differences, the expression of P-gp in human brain and spinal cord was lower than in rats and dogs but relatively comparable to that in monkeys. However, no species related differences were seen in the expression at the DRG level. Double-labelling using an antibody against a marker of endothelial cells confirmed that P-gp was exclusively localized in capillary endothelial cells. This study highlights the cross species similarities and differences in the expression of P-gp and thus serves as a vital step in understanding the translation of exposure of P-gp substrates to human

Evaluation of P-glycoprotein expression in pain relevant tissues: understanding translation of efflux from preclinical species to human

Various efflux transporters, such as P-glycoprotein (P-gp) are now widely accepted to have profound influence on the disposition of substrates. Nevertheless, there is paucity of information about their expression and functionality in the pain relevant tissues (such as brain, spinal cord and dorsal root ganglia (DRG)) across various species. Therefore, our attempts were directed at evaluating P-gp expression in these tissues to understand its effect on the central nervous system (CNS) disposition. As a means of characterizing the normal tissue distribution of P-gp, immunohistochemistry was performed with two antibodies (C219 and H241) directed against different epitopes of MDR1 gene. Notable expression of P-gp was detected in the DRG of Sprague Dawley rat, Beagle Dog, Cynomolgous monkey as well as human. The expression of P-gp was observed in the CNS tissues with evident species differences, the expression of P-gp in human brain and spinal cord was lower than in rats and dogs but relatively comparable to that in monkeys. However, no species related differences were seen in the expression at the DRG level. Double-labelling using an antibody against a marker of endothelial cells confirmed that P-gp was exclusively localized in capillary endothelial cells. This study highlights the cross species similarities and differences in the expression of P-gp and thus serves as a vital step in understanding the translation of exposure of P-gp substrates to human

A randomized double-blind feasibility study comparing cetirizine and diphenhydramine in the prevention of paclitaxel-associated infusion-related reactions : the PREMED-F1 study

Purpose. Cetirizine is a less sedative alternative to diphenhydramine for the prevention of infusion-related reactions (IRR) to paclitaxel. However, its use remains controversial. In this study, we assessed feasibility for a future definitive non-inferiority trial comparing cetirizine to diphenhydramine as premedication to prevent paclitaxel-related IRR. Methods. This was a single center randomized prospective feasibility study. Participants were paclitaxel-naive cancer patients scheduled to start paclitaxel chemotherapy. They were randomly assigned to receive either intravenous diphenhydramine 50 mg + oral placebo (control) or intravenous placebo + oral cetirizine 10 mg (intervention) for their first two paclitaxel treatments. The percentage of eligible patients completing a first paclitaxel treatment and the recruitment rate were assessed (feasibility outcomes). Drowsiness was measured at baseline and at selected time points using the Stanford Sleepiness Scale (SSS) (safety outcome). IRR events were also documented (efficacy outcome). Results. Among 37 eligible patients, 27 were recruited and randomized (control 13; intervention 14) and 25 completed the study. The recruitment rate was 4.8 participants/month, meeting the primary feasibility target. Drowsiness was the main adverse effect associated with the premedication. The increase in drowsiness compared to baseline (ΔSSS) was greater in the diphenhydramine group compared to the cetirizine group (median ΔSSS 2 (IQR 3.25) vs median ΔSSS 0 (IQR 1), p < 0.01) when measured one hour after the premedication administration. One participant had an IRR and no unexpected serious adverse event occurred. Conclusion. The trial methods were feasible in terms of recruitment, retention and safety. Cetirizine was significantly less sedating than diphenhydramine. IRR were infrequent and a larger trial is warranted to confirm non-inferiority for IRR prevention