[Show abstract][Hide abstract] ABSTRACT: Pharmacological studies have yielded valuable insights into the role of the serotonin 2A (5-HT2A) receptor in major depressive disorder (MDD) and antidepressant drugs (ADs) response. However, it is still unknown whether genetic variants in the HTR2A gene affect the therapeutic outcome of ADs and the mechanism underlying the regulation of such response remains poorly described. In this context, a translational human-mouse study offers a unique opportunity to address the possibility that variations in the HTR2A gene may represent a relevant marker to predict the efficacy of ADs. In a first part of this study, we investigated in depressed patients the effect of three HTR2A single nucleotide polymorphisms (SNPs), selected for their potential functional consequences on 5-HT2A receptor (rs6313, rs6314 and rs7333412), on response and remission rates after 3 months of antidepressant treatments. We also explored the consequences of the constitutive genetic inactivation of the 5-HT2A receptor (i.e. in 5-HT2A(-/-) mice) on the activity of acute and prolonged administration of SSRIs. Our clinical data indicate that GG patients for the rs7333412 SNP were less prone to respond to ADs than AA/AG patients. In the preclinical study, we demonstrated that the 5-HT2A receptor exerts an inhibitory influence on the neuronal activity of the serotonergic system after acute administration of SSRIs. However, while the chronic administration of the SSRIs escitalopram or fluoxetine elicited a progressive increased in the firing rate of 5-HT neurons in 5-HT2A(+/+) mice, it failed to do so in 5-HT2A(-/-) mutants. These electrophysiological impairments were associated with a decreased ability of the chronic administration of fluoxetine to stimulate hippocampal plasticity and to produce antidepressant-like activities. Genetic loss of the 5-HT2A receptor compromised the activity of chronic treatment with SSRIs, making this receptor a putative marker to predict ADs response.
Full-text · Article · Jan 2016 · Neuropharmacology
[Show abstract][Hide abstract] ABSTRACT: Voriconazole (VRC) is mainly metabolized by CYP2C19 and CYP3A4 and exhibits a wide inter- and intra-individual variability requiring therapeutic drug monitoring (TDM). We present a case of VRC therapy failure in a patient carrying a CYP2C19*17/*17 genotype. A 26-year-old Caucasian woman treated for an acute leukemia developed a neutropenic fever associated to a respiratory distress. Seventeen days after the introduction of a standard VRC antifungal treatment, she suffered from cough and hemoptysis, detection of fungal blood markers remained positive and chest high-resolution CT scan revealed newer lesions in lungs, suggesting a refractory aspergillosis. After a 2-hour intravenous infusion of 400mg dose, VRC concentrations were 3.48, 1.10, 0.22 and 0.17 mg/L at 2, 4, 8 and 12 hours respectively. Area under the concentration time curve from zero to infinity, clearance and terminal half-life were estimated at 11.1 h.mL/min, 35.9 L/h and 2.3 h respectively. The concentration ratio of the N-oxide metabolite of VRC (VRC-N-oxide) over VRC increased very quickly after the infusion and remained extremely high at the 12th hour (3.2 and 10.5 respectively). CYP2C19 genotyping revealed a homozygous *17 mutation, maybe partly explaining this ultrarapid metabolism. However, co-medications and disease-induced modulation of the CYP2C19 and CYP3A4 activities cannot be excluded. The measurement of serum VRC-N-oxide supports the TDM of VRC. A low VRC concentration associated to a high concentration ratio of VRC-N-oxide over VRC suggest a possible ultrarapid metabolism of VRC and should prompt to adapt the treatment.
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No preview · Article · Jul 2015 · British Journal of Clinical Pharmacology
[Show abstract][Hide abstract] ABSTRACT: We propose an extensive review of the literature about BDNF/TRKB/P75NTR polymorphisms and their consequences on antidepressant efficacy in depressed patients. Five genome-wide association studies and 30 association studies were included. Twenty seven studies focused on the Val66Met polymorphism (rs6265), the Met allele being associated with a higher antidepressant efficacy only in Asian patients. Other BDNF/TRKB/P75NTR polymorphisms (BDNF: rs7103411, rs7124442, rs908867, rs2049046, rs61888800, rs10501087, rs1491850; TRKB: rs10868223, rs11140778, rs1565445, rs1659412; P75NTR: rs2072446) were reported to be associated with antidepressant efficacy but these results were not replicated. Finally, there are 15 positive studies among 30 studies regarding BDNF/TRKB/P75NTR polymorphisms. The only SNP which benefits of at least three positive studies is the BDNF Val66Met polymorphism (rs6265). Consequently, with a lack of good and consistent studies, the clinical utility of BDNF in treatment selection is far from clear. We propose several recommendations for further studies.
[Show abstract][Hide abstract] ABSTRACT: BACKGROUND:
Whether the Brain Derived Neurotrophic Factor (BDNF) Val66Met polymorphism can predict antidepressant drug efficacy in depressed patients remains unclear, suggesting that it may depend on antidepressant classes. We assessed the impact of Val66Met polymorphism on antidepressant response and remission depending on antidepressant classes.
In a 6-month prospective, real-world setting, treatment study, 345 Caucasian depressed patients requiring a new or different drug treatment with a selective serotonin reuptake inhibitor (SSRI), a serotonin and noradrenalin reuptake inhibitor (SNRI) or a tricyclic antidepressant (TCA), were genotyped and assessed for response and remission.
231 (67%) patients were homozygous for the Val66 allele (Val/Val) and 114 (33%) were carriers of Met allele (Met). 152 (44.1%) patients were treated with SSRI, the others with SNRI/TCA. Both response and remission were explained by interactions between the Val66Met polymorphism and antidepressant drug classes (multivariate models adjusted for propensity-scores: p=0.02 and p=0.03 respectively). With SSRI, Val/Val patients had a higher response rate 3 months post-treatment than Met patients (68.1% versus 44%; adjusted-OR: 3.04, IC95% [1.05; 9.37], p=0.04). With SNRI/TCA, Val/Val patients had a lower remission rate 6 months post-treatment than Met patients (33.3% versus 60.9%, adjusted-OR: 0.27, IC95% [0.09; 0.76], p=0.02).
Limited sample size.
This study argues for a personalized prescription of antidepressants in Caucasian patients with major depressive disorder, based on the BDNF Val66Met polymorphism: SSRI should be preferred for Val/Val patients and SNRI/TCA for Met patients. Further studies are required to confirm these data.
[Show abstract][Hide abstract] ABSTRACT: An association between serotonin 2A receptor (5-HT2AR), encoded by HTR2A gene, and major depressive disorder (MDD) has been suggested. Here, we combined preclinical and ecological clinical approaches to explore the impact of impaired 5-HT2AR-mediated transmission on MDD or anxio-depressive-like phenotype in mice.
Htr2a knock-out mice (Htr2a-/- ) and wild-type mice were compared for the ability of chronic corticosterone to elicit some anxio-depressive-like phenotype in three behavioral paradigms (elevated plus maze, tail suspension test and splash test). Accordingly, two single nucleotide polymorphisms of the HTR2A gene (rs6314 ie His452Tyr and rs6313 ie 102C/T), which specific allelic variants may decrease 5-HT2AR-mediated transmission (as in Htr2a-/-mice), were studied in a sample of 485 Caucasian patients with MDD.
In response to chronic corticosterone exposure, Htr2a-/- mice displayed more pronounced anxiodepressive-like phenotype than wild-type mice, as shown by a significant higher “emotionality score” (p < 0.01). In patients, the C allele of rs6313 was more frequent in depressed patients (p = 0.019) and was also associated with a more severe major depressive episode (p = 0.03).
This translational and ecological study involving constitutive Htr2a-/- knock-out mice and related SNPs in depressed patients suggests that a lower neurotransmission at the 5-HT2AR may favor the susceptibility and severity of MDE. It also suggests that specific allelic variants of the rs6313 and rs6314 may reduce 5-HT2AR-mediated transmission.
Full-text · Article · Oct 2014 · Progress in Neuro-Psychopharmacology and Biological Psychiatry
[Show abstract][Hide abstract] ABSTRACT: The aim of this study was to evaluate the association between the functional polymorphic region of the serotonin transporter gene (5-HTTLPR) and antidepressant efficacy in menopausal and non-menopausal women. Since serotonergic system has been shown to be linked to estrogens, menopausal status of women may explain previous contradictory results on antidepressant efficacy in major depressive episode related to 5-HTTLPR in women. Seventy-four women (43 non-menopausal and 31 menopausal) and 29 men with a major depressive episode were genotyped for the 5-HTTLPR and assessed prospectively for antidepressant efficacy after 4 weeks of treatment. Non-menopausal women with at least one copy of the long allele had better antidepressant efficacy than those who were homozygous for the short allele, whereas no difference was found in menopausal women. Furthermore, antidepressant response was correlated with an interaction between the 5-HTTLPR polymorphism and age in women, but not in men. This finding suggested that the differences in antidepressant response were not linked to age but, rather, to menopausal status of women. Further research on a bigger sample is needed with steroids measurements to determine how menopausal status and 5-HTTLPR polymorphism influence antidepressant response.
No preview · Article · Sep 2014 · Archives of Women s Mental Health
[Show abstract][Hide abstract] ABSTRACT: Co-administration of methotrexate (MTX) and proton pump inhibitors (PPIs) can cause a pharmacokinetic interaction that result in delayed MTX elimination and a subsequent increase in MTX blood concentrations. Human organic anion transporters (OATs) are responsible for renal tubular secretion of MTX, and are thought to be involved in this drug interaction. The aim of this study was to evaluate the inhibitory potencies of PPIs on hOAT1 and hOAT3, the two isoforms of OATs predominantly expressed in kidney proximal tubules. Using stably transfected cell systems expressing the uptake transporters HEK-hOAT1 and HEK-hOAT3, we analyzed the inhibitory potencies of omeprazole, lansoprazole and pantoprazole, on OAT-mediated [(3)H]ES, [(3)H]PAH and [(3)H]MTX uptake in vitro. hOAT3 is a high affinity transporter for MTX (Km = 21.17 ± 5.65 μM). Omeprazole, lansoprazole and pantoprazole inhibited [(3)H]MTX uptake in HEK-hOAT3 cells with IC50 of 6.8 ± 1.16 μM, 1.14 ± 0.26 μM and 4.45 ± 1.62 μM respectively and [(3)H]ES uptake in HEK-hOAT3 cells with IC50 of 20.59 ± 4.07 μM, 3.96 ± 0.96 μM and 7.89 ± 2.31 μM respectively. Furthermore, omeprazole, lansoprazole and pantoprazole exhibited concentration-dependent inhibition of PAH uptake on hOAT1 (IC50 = 4.32 ± 1.26 μM, 7.58 ± 1.06 μM and 63.21 ± 4.74 μM respectively). These in vitro results suggest that inhibition of [(3)H]MTX transport by PPIs via hOAT3 inhibition, probably explains the drug-drug interactions between MTX and PPIs and should be considered for others OATs substrates.
No preview · Article · Sep 2014 · Drug metabolism and disposition: the biological fate of chemicals
[Show abstract][Hide abstract] ABSTRACT: The cytochrome P450 2D6 (CYP2D6) is involved in the metabolism of most antidepressants. Comedication with a potent CYP2D6 inhibitor can convert patients with extensive metabolizer (EM) or ultra-rapid metabolizer (UM) genotypes into poor metabolizer (PM) phenotypes. Since comedication is frequent in depressed patients treated with antidepressants, we investigated the effect of the CYP2D6 composite phenotype on antidepressant efficacy, taking into account both the CYP2D6 genotype and comedication with CYP2D6 inhibitors. 87 Caucasian in patients with a major depressive episode were prospectively treated with flexible doses of antidepressant monotherapy as well as comedications and genotyped for the major CYP2D6 alleles (CYP2D6*3 rs35742686, *4 rs3892097, *5 del, *6 rs5030655, and *2xN). They were classified for CYP2D6 composite phenotype and assessed for antidepressant response after 4 weeks. In terms of genotypes (g), 6 subjects were UMg, 6 PMg, and 75 EMg. Ten patients were coprescribed a CYP2D6 inhibitor, resulting in the following composite phenotypes (cp): 5 UMcp, 16 PMcp, and 66 EMcp. Whereas none of the CYP2D6 genotypes were significantly associated with antidepressant response, UMcp had a lower antidepressant response than PMcp or EMcp (respectively: 39.0 ± 17.9, 50.0 ± 26.0, and 61.6 ± 23.4, p = 0.02). Despite small sample size, this study suggests that a CYP2D6 composite phenotype, taking into account both genotype and comedications with CYP2D6 inhibitors, could predict CYP2D6 substrate antidepressants response. Thus, to optimize antidepressant response, CYP2D6 genotype could be performed and comedications with CYP2D6 inhibitors should be avoided, when prescribing CYP2D6 substrate antidepressants.
No preview · Article · Jul 2014 · Journal of Neural Transmission
[Show abstract][Hide abstract] ABSTRACT: Tacrolimus, an immunosuppressant drug, presents a narrow therapeutic window and a large pharmacokinetic variability with poor correlation between drug dosing regimen and blood concentration. The objective was to identify predictive factors influencing tacrolimus trough concentrations (C0) using a bottom-up approach. A physiologically based pharmacokinetic (PBPK) model of tacrolimus was proposed, taking into account the body weight, the proportion of fat (P fat), hematocrit, lipid fraction of organs, typical intrinsic clearance (CLityp), CYP3A5 genotype of liver donor, plasma unbound fraction of tacrolimus (fup), and concomitant drugs (CYP3A4 inhibitors). For the evaluation of the PBPK model, mean C0 and concentrations 2 h after oral dose of tacrolimus were compared with those from 66 liver transplant recipients included in a multicentric pharmacokinetic study and were found very close. Tacrolimus concentration profiles were simulated in a virtual population defined by a set of covariate values similar to those from the real population. The sensitivity of tacrolimus C0 with respect to each covariate has been tested to identify the most influential ones. With the range of covariate values tested, the impact of each covariate on tacrolimus C0 may be ranked as follows: fup, CLityp, bioavailability, body weight, hematocrit, CYP3A5 polymorphism, P fat, and CYP3A4 inhibitory drug-drug interactions. Values for initial dosing regimen of tacrolimus in order to reach a C0 of 10 ng/ml at day 5 (assuming a constant dosing schedule) as a function of CYP3A5 donor genotype and patient's hematocrit and body weight are proposed.
No preview · Article · Feb 2014 · The AAPS Journal
[Show abstract][Hide abstract] ABSTRACT: We investigated the population pharmacokinetics and pharmacogenetics of efavirenz in 307 patients coinfected with human immunodeficiency
virus and tuberculosis and included in the Cambodian Early vs Late Initiation of Antiretrovirals trial (CAMELIA) in Cambodia.
Efavirenz (600 mg/d) and stavudine plus lamivudine were administered in addition to standard antituberculosis treatment, including
rifampicin and isoniazid. Blood samples were obtained a mean of 14 hours after efavirenz intake at weeks 2 and 6 after initiation
of efavirenz and weeks 22 (efavirenz plus antituberculosis drugs) and 50 (efavirenz alone) after initiation of antituberculosis
treatment. Ten patients participated in an extensive pharmacokinetic study after week 50. CYP2B6 G516T and C485-18T polymorphisms were the most significant covariates, with weight showing a significant minor effect. Change in efavirenz apparent
clearance in patients taking both efavirenz and antituberculosis treatment was highly dependent on NAT2 polymorphism, as a possible surrogate of isoniazid exposure. Patients carrying the CYP2B6 516 TT genotype and slow-acetylation NAT2 phenotype had the lowest efavirenz apparent clearance. These data suggest that the inducing effect of rifampicin is counterbalanced
by a concentration-dependant inhibitory effect of isoniazid on efavirenz clearance.
[Show abstract][Hide abstract] ABSTRACT: The SLCO1B1 c.521T>C polymorphism is associated with statin plasma levels and simvastatin-induced adverse drug reactions. We studied whether the c.521T>C polymorphism is associated with dose decreases or switches to other cholesterol-lowering drugs during simvastatin and atorvastatin therapy, because these events are indicators of adverse drug reactions.
We identified 1939 incident simvastatin and atorvastatin users in the Rotterdam Study, a population-based cohort study. Associations were studied using Cox proportional hazards analysis. Meta-analysis was performed with data from the Utrecht Cardiovascular Pharmacogenetics study.
Simvastatin users with the c.521 CC genotype had a significantly higher risk of a dose decrease or switch than users with the TT genotype [hazard ratio (HR) 1.74, 95% confidence interval (CI) 1.05-2.88]. Female sex, age below 70 years, and low starting dose were risk factors. In atorvastatin users with starting dose of more than 20 mg, the risk of a dose decrease or switch was higher in users carrying a C allele than in users with the TT genotype (HR 3.26, 95% CI 1.47-7.25). In the meta-analysis the association in simvastatin users remained, with a significantly higher risk of a dose decrease or switch in simvastatin users with two minor alleles (HR 1.69, 95% CI 1.05-2.73). For atorvastatin users no significant association was found.
In simvastatin users in the Rotterdam Study, we demonstrated an association between the c.521T>C polymorphism and dose decrease or switching, as indicators of adverse drug reactions, and provided risk factors for this association. For atorvastatin, an association was found in users with a starting dose of more than 20 mg.
Full-text · Article · Nov 2013 · Pharmacogenetics and Genomics