Association between CYP2D6 Genotypes and the Risk of Antidepressant Discontinuation, Dosage Modification and the Occurrence of Maternal Depression during Pregnancy

Influence of red wine polysaccharides on cytochrome P450 enzymes and inflammatory parameters in tumor models

The soluble fraction of polysaccharides from cabernet franc red wine (SFP) previously showed antitumoral effects by modulating the immune system. The present study tested the hypothesis that the SFP can regulate CYPs in vitro in HepG2 cells and in vivo in Walker-256 tumor-bearing rats. The SFP was used in the following protocols: (i) solid tumor, (ii) liquid tumor, and (iii) chemopreventive solid tumor. The SFP reduced solid tumor growth in both solid tumor protocols but did not inhibit liquid tumor development. The SFP reduced total CYP levels in the solid and liquid tumor protocols and reduced the gene expression of Cyp1a1 and Cyp2e1 in rats and CYP1A2 in HepG2 cells. An increase of N-acetylglucosaminidase activity was observed in all SFP-treated rats, and TNF-α levels increased in the solid tumor protocol in the vehicle, SFP, and vincristine (positive control) groups. The chemopreventive solid tumor protocol did not modify CYP levels in the liver or intestine or N-acetylglucosaminidase and myeloperoxidase activity in the liver. The in vitro digestion and nuclear magnetic resonance analyses suggested that SFP was minimally modified in the gastrointestinal system. In conclusion, SFP inhibited CYPs both in vivo and in vitro, likely as a result of its immunoinflammatory actions.

Precision Medicine Approaches to Mental Health Care

Developing a more comprehensive understanding of the physiological underpinnings of mental illness, precision medicine has the potential to revolutionize psychiatric care. With recent breakthroughs in next-generation multi-omics technologies and data analytics, it is becoming more feasible to leverage multimodal biomarkers, from genetic variants to neuroimaging biomarkers, to objectify diagnostics and treatment decisions in psychiatry and improve patient outcomes. Ongoing work in precision psychiatry will parallel progress in precision oncology and cardiology to develop an expanded suite of blood- and neuroimaging-based diagnostic tests, empower monitoring of treatment efficacy over time, and reduce patient exposure to ineffective treatments. The emerging model of precision psychiatry has the potential to mitigate some of psychiatry's most pressing issues, including improving disease classification, lengthy treatment duration, and suboptimal treatment outcomes. This narrative-style review summarizes some of the emerging breakthroughs and recurring challenges in the application of precision medicine approaches to mental health care.

Optimising Fluvoxamine Maternal/Fetal Exposure during Gestation: A Pharmacokinetic Virtual Clinical Trials Study

Fluvoxamine plasma concentrations have been shown to decrease throughout pregnancy. CYP2D6 polymorphisms significantly influence these changes. However, knowledge of an optimum dose adjustment according to the CYP2D6 phenotype is still limited. This study implemented a physiologically based pharmacokinetic modelling approach to assess the gestational changes in fluvoxamine maternal and umbilical cord concentrations. The optimal dosing strategies during pregnancy were simulated, and the impact of CYP2D6 phenotypes on fluvoxamine maternal and fetal concentrations was considered. A significant decrease in fluvoxamine maternal plasma concentrations was noted during gestation. As for the fetal concentration, a substantial increase was noted for the poor metabolisers (PM), with a constant level in the ultrarapid (UM) and extensive (EM) metabolisers commencing from gestation week 20 to term. The optimum dosing regimen suggested for UM and EM reached a maximum dose of 300 mg daily at gestational weeks (GW) 15 and 35, respectively. In contrast, a stable dose of 100 mg daily throughout gestation for the PM is sufficient to maintain the fluvoxamine plasma concentration within the therapeutic window (60-230 ng/mL). Dose adjustment during pregnancy is required for fluvoxamine, particularly for UM and EM, to maintain efficacy throughout the gestational period.

A cross-sectional study of the relationship between CYP2D6 and CYP2C19 variations and depression symptoms, for women taking SSRIs during pregnancy

Depression during pregnancy affects 10-15% of women, and 5% of women take antidepressants during pregnancy. Clinical guidelines provide recommendations for selective serotonin reuptake inhibitor (SSRI) drug choice and dose based on CYP2D6 and CYP2C19 genotype; however, they are based on evidence from non-pregnant cohorts. This study aimed to test the hypothesis that women with function-altering variants (increased, decreased, or no function) in these pharmacogenes, taking SSRIs prenatally, would have more depression symptoms than women whose pharmacogenetic variants are associated with normal SSRI metabolism. Comprehensive CYP2D6 and CYP2C19 genotyping using a range of methods, including gene copy number analysis, was performed as secondary analyses on two longitudinal cohorts of pregnant women (N = 83) taking the SSRIs paroxetine, citalopram, escitalopram, or sertraline. The Kruskal-Wallis test compared mean depression scores across four predicted metabolizer groups: poor (n = 5), intermediate (n = 10), normal (n = 53), and ultrarapid (n = 15). There were no significant differences between mean depression scores across the four metabolizer groups (H(3) = .73, p = .87, eta-squared = .029, epsilon-squared = .0089). This is the first study of the relationship in pregnancy between CYP2C19 pharmacogenetic variations and depression symptoms in the context of SSRI use. Findings from this initial study do not support the clinical use of pharmacogenetic testing for SSRI use during the second or third trimesters of pregnancy, but these findings should be confirmed in larger cohorts. There is an urgent need for further research to clarify the utility of pharmacogenetic testing for pregnant women, especially as companies offering direct-to-consumer genetic testing expand their marketing efforts.

Potential pharmacogenomic targets in bipolar disorder: considerations for current testing and the development of decision support tools to individualize treatment selection

Background

Treatment in bipolar disorder (BD) is commonly applied as a multimodal therapy based on decision algorithms that lack an integrative understanding of molecular mechanisms or a biomarker associated clinical outcome measure. Pharmacogenetics/genomics study the individual genetic variation associated with drug response. This selective review of pharmacogenomics and pharmacogenomic testing (PGT) in BD will focus on candidate genes and genome wide association studies of pharmacokinetic drug metabolism and pharmacodynamic drug response/adverse event, and the potential role of decision support tools that incorporate multiple genotype/phenotype drug recommendations.

Main body

We searched PubMed from January 2013 to May 2019, to identify studies reporting on BD and pharmacogenetics, pharmacogenomics and PGT. Studies were selected considering their contribution to the field. We summarize our findings in: targeted candidate genes of pharmacokinetic and pharmacodynamic pathways, genome-wide association studies and, PGT platforms, related to BD treatment. This field has grown from studies of metabolizing enzymes (i.e., pharmacokinetics) and drug transporters (i.e., pharmacodynamics), to untargeted investigations across the entire genome with the potential to merge genomic data with additional biological information.

Conclusions

The complexity of BD genetics and, the heterogeneity in BD drug-related phenotypes, are important considerations for the design and interpretation of BD PGT. The clinical applicability of PGT in psychiatry is in its infancy and is far from reaching the robust impact it has in other medical disciplines. Nonetheless, promising findings are discovered with increasing frequency with remarkable relevance in neuroscience, pharmacology and biology.

Long-Distance Phasing of a Tentative "Enhancer" Single-Nucleotide Polymorphism With CYP2D6 Star Allele Definitions

BACKGROUND

The CYP2D6 gene locus has been extensively studied over decades, yet a portion of variability in CYP2D6 activity cannot be explained by known sequence variations within the gene, copy number variation, or structural rearrangements. It was proposed that rs5758550, located 116 kb downstream of the CYP2D6 gene locus, increases gene expression and thus contributes to variability in CYP2D6 activity. This finding has, however, not been validated. The purpose of the study was to address a major technological barrier, i.e., experimentally linking rs5758550, also referred to as the "enhancer" single-nucleotide polymorphism (SNP), to CYP2D6 haplotypes >100 kb away. To overcome this challenge is essential to ultimately determine the contribution of the "enhancer" SNP to interindividual variability in CYP2D6 activity.

METHODS

A large ethnically mixed population sample (n=3,162) was computationally phased to determine linkage between the "enhancer" SNP and CYP2D6 haplotypes (or star alleles). To experimentally validate predicted linkages, DropPhase2D6, a digital droplet PCR (ddPCR)-based method was developed. 10X Genomics Linked-Reads were utilized as a proof of concept.

RESULTS

Phasing predicted that the "enhancer" SNP can occur on numerous CYP2D6 haplotypes including CYP2D6*1, *2, *5, and *41 and suggested that linkage is incomplete, i.e., a portion of these alleles do not have the "enhancer" SNP. Phasing also revealed differences among the European and African ancestry data sets regarding the proportion of alleles with and without the "enhancer" SNP. DropPhase2D6 was utilized to confirm or refute the predicted "enhancer" SNP location for individual samples, e.g., of n=3 samples genotyped as *1/*41, rs5758550 was on the *41 allele of two samples and on the *1 allele of one sample. Our findings highlight that the location of the "enhancer" SNP must not be assigned by "default." Furthermore, linkage between the "enhancer" SNP and CYP2D6 star allele haplotypes was confirmed with 10X Genomics technology.

CONCLUSIONS

Since the "enhancer" SNP can be present on a portion of normal, decreased, or no function alleles, the phase of the "enhancer" SNP must be considered when investigating the impact of the "enhancer" SNP on CYP2D6 activity.

Precision dosing-based optimisation of paroxetine during pregnancy for poor and ultrarapid CYP2D6 metabolisers: a virtual clinical trial pharmacokinetics study

Objective

Paroxetine has been demonstrated to undergo gestation-related reductions in plasma concentrations, to an extent which is dictated by the polymorphic state of CYP 2D6. However, knowledge of appropriate dose titrations is lacking.

Methods

A pharmacokinetic modelling approach was applied to examine gestational changes in trough plasma concentrations for CYP 2D6 phenotypes, followed by necessary dose adjustment strategies to maintain paroxetine levels within a therapeutic range of 20–60 ng/ml.

Key findings

A decrease in trough plasma concentrations was simulated throughout gestation for all phenotypes. A significant number of ultrarapid (UM) phenotype subjects possessed trough levels below 20 ng/ml (73–76%) compared to extensive metabolisers (EM) (51–53%).

Conclusions

For all phenotypes studied, there was a requirement for daily doses in excess of the standard 20 mg dose throughout gestation. For EM, a dose of 30 mg daily in trimester 1 followed by 40 mg daily in trimesters 2 and 3 is suggested to be optimal. For poor metabolisers (PM), a 20 mg daily dose in trimester 1 followed by 30 mg daily in trimesters 2 and 3 is suggested to be optimal. For UM, a 40 mg daily dose throughout gestation is suggested to be optimal.

Impact of antidepressant use, discontinuation, and dosage modification on maternal depression during pregnancy

Women tend to discontinue their antidepressants during pregnancy. This study compared the risk of depressive symptoms in the second-half of pregnancy in women who discontinue or continue with or without dosage modification their antidepressant during gestation. Women were eligible if they called MothertoBaby during 2006-2010 and within 14 completed weeks of pregnancy. A total of 367 pregnant women were included. The Edinburgh Postnatal Depression Scale (EPDS) was used to measure depression during the first and second half of pregnancy. Presence of depressive symptoms was defined as EPDS ≥13. Among participants, 149 did not use antidepressants, 38 used antidepressants at the beginning of pregnancy but discontinued before the end of second-trimester, and 180 used antidepressants continuously throughout pregnancy. Among continued users, 46 modified antidepressant dosage before the end of the second trimester, and 134 did not modify dosage. The majority of antidepressant users (150/218, 68.8%) had mild to moderate depression. Thirteen percent (13%) of women who continued antidepressant use throughout pregnancy without dosage modification remained depressed. Adjusting for potential confounders including maternal depression/anxiety before pregnancy, and compared to non-users, discontinued users were 5.95 times (95%CI: 1.54-23.02), and continued users without dosage modification 4.59 times (95%CI: 1.44-14.64) more at risk of depression in the second-half of pregnancy. Those with dosage modifications were at a similar risk of depression during pregnancy than non-users (adjusted odds ratio 0.58, 95%CI: 0.06-5.52). In conclusion, in a cohort of mild to moderate depressive pregnant women, discontinuing or continuing antidepressant use without dosage modification during pregnancy were associated with an increased risk of depression during the remaining gestational period.

SSRIs and SNRIs (SRI) in Pregnancy: Effects on the Course of Pregnancy and the Offspring: How Far Are We from Having All the Answers?

Serotonin has important roles in the development of the brain and other organs. Manipulations of synaptic serotonin by drugs such as serotonin reuptake inhibitors (SRI) or serotonin norepinephrine reuptake inhibitors (SNRI) might alter their development and function. Of interest, most studies on the outcome of prenatal exposure to SRI in human have not found significant embryonic or fetal damage, except for a possible, slight increase in cardiac malformations. In up to a third of newborns exposed to SRI, exposure may induce transient neonatal behavioral changes (poor neonatal adaptation) and increased rate of persistent pulmonary hypertension. Prenatal SRI may also cause slight motor delay and language impairment but these are transient. The data on the possible association of prenatal SRIs with autism spectrum disorder (ASD) are inconsistent, and seem to be related to pre-pregnancy treatment or to maternal depression. Prenatal SRIs also appear to affect the hypothalamic hypophyseal adrenal (HPA) axis inducing epigenetic changes, but the long-term consequences of these effects on humans are as yet unknown. SRIs are metabolized in the liver by several cytochrome P450 (CYP) enzymes. Faster metabolism of most SRIs in late pregnancy leads to lower maternal concentrations, and thus potentially to decreased efficacy which is more prominent in women that are rapid metabolizers. Studies suggest that the serotonin transporter SLC6A4 promoter is associated with adverse neonatal outcomes after SRI exposure. Since maternal depression may adversely affect the child's development, one has to consider the risk of SRI discontinuation on the fetus and the child. As with any drug treatment in pregnancy, the benefits to the mother should be considered versus the possible hazards to the developing embryo/fetus.

Use of antidepressants and anxiolytics in early pregnancy and the risk of preeclampsia and gestational hypertension: a prospective study

Background

We investigated the association between antidepressant and anxiolytic exposure during the first and early second trimester of pregnancy (< 16 weeks), and hypertensive disorders of pregnancy (including preeclampsia and gestational hypertension) in women with singleton pregnancy.

Methods

This study is based on a large prospective cohort of 7866 pregnant women. We included pregnant women aged 18 years or older without chronic hepatic or renal disease at the time of recruitment. Participants lost to the follow-up, with multiple pregnancies and pregnancy terminations, miscarriages or fetal deaths before 20 weeks of gestation were excluded from the study, as well as women with no data on the antidepressant/anxiolytic medication use during pregnancy. Information concerning antidepressant or anxiolytic medication use was extracted from hospital records after delivery. The associations between their use and the risk of gestational hypertension or preeclampsia were calculated.

Results

The final sample for analysis included 6761 participants including 218 (3.2%) women who were exposed to antidepressant and/or anxiolytic medication before the 16th week of gestation. Forty-one women had a non-medicated depression or anxiety during the pregnancy. Moreover, 195 (2.9%) and 122 (1.8%) women developed gestational hypertension and preeclampsia respectively. When compared to women unexposed to antidepressant/anxiolytic medication, depression and anxiety, those using antidepressant and/or anxiolytic drugs before the 16th week of gestation were at increased risk of preeclampsia (adjusted odd ratio (aOR) 3.09 [CI_95% 1.56–6.12]), especially if they continued their medication after the 16th week (aOR 3.41 [CI_95% 1.66–7.02]) compared to those who did not (1.60 [CI_95% 0.21–12.34]).

Conclusions

Women exposed to antidepressant and/or anxiolytic medication before the 16th week of pregnancy have a 3-fold increased risk for preeclampsia when compared to women unexposed to antidepressant/anxiolytic medication, depression and anxiety. Also, our results suggested that women who stopped their medication before the 16th week of pregnancy could be benefit from reduced preeclampsia risk.

The dynamic serotonin system of the maternal brain

Many pregnant and postpartum women worldwide suffer from high anxiety and/or depression, which can have detrimental effects on maternal and infant well-being. The first-line pharmacotherapies for prepartum and postpartum affective disorders continue to be the selective serotonin reuptake inhibitors (SSRIs), despite the lack of large well-controlled studies demonstrating their efficacy in reproducing women and the potential for fetal/neonatal exposure to the drugs. Prepartum or postpartum use of SSRIs or other drugs that modulate the brain's serotonin system is also troubling because very little is known about the typical, let alone the atypical, changes that occur in the female central serotonin system across reproduction. We do know from a handful of studies of women and female laboratory rodents that numerous aspects of the central serotonin system are naturally dynamic across reproduction and are also affected by pregnancy stress (a major predisposing factor for maternal psychopathology). Thus, it should not be assumed that the maternal central serotonin system being targeted by SSRIs is identical to non-parous females or males. More information about the normative and stress-derailed changes in the maternal central serotonin system is essential for understanding how serotonin is involved in the etiology of, and the best use of SSRIs for potentially treating, affective disorders in the pregnant and postpartum populations.

Selective Serotonin Reuptake Inhibitor Use During Pregnancy and Major Malformations: The Importance of Serotonin for Embryonic Development and the Effect of Serotonin Inhibition on the Occurrence of Malformations

Bioelectric signaling is transduced by neurotransmitter pathways in many cell types. One of the key mediators of bioelectric control mechanisms is serotonin, and its transporter SERT, which is targeted by a broad class of blocker drugs (selective serotonin reuptake inhibitors [SSRIs]). Studies showing an increased risk of multiple malformations associated with gestational use of SSRI have been accumulating but debate remains on whether SSRI as a class has the potential to generate these malformations. This review highlights the importance of serotonin for embryonic development; the effect of serotonin inhibition during early pregnancy on the occurrence of multiple diverse malformations that have been shown to occur in human pregnancies; that the risks outweigh the benefits of SSRI use during gestation in populations of mild to moderately depressed pregnant women, which encompass the majority of pregnant depressed women; and that the malformations seen in human pregnancies constitute a pattern of malformations consistent with the known mechanisms of action of SSRIs. We present at least three mechanisms by which SSRI can affect development. These studies highlight the relevance of basic bioelectric and neurotransmitter mechanism for biomedicine.

Does obtaining CYP2D6 and CYP2C19 pharmacogenetic testing predict antidepressant response or adverse drug reactions?

Treatment non-response and adverse reactions are common in patients receiving antidepressants. Personalizing psychiatric treatment based on pharmacogenetic testing has been proposed to help clinicians guide antidepressant selection and dosing. This systematic literature review assesses the two most robustly studied drug-metabolizing enzymes, CYP2D6 and CYP2C19, and examines whether obtaining CYP2D6 and CYP2C19 testing can be used to predict antidepressant response or adverse drug reactions in order to improve clinical outcomes. In general, literature reviews published prior to 2013 indicated that results have been inconsistent linking CYP2D6 and CYP2C19 to antidepressant treatment outcomes, suggesting that more evidence is required to support the clinical implementation of genotyping to predict outcomes. We thus performed an extensive and systematic literature review, focusing on studies published from 2013 through 2018. Sixteen studies were found to be relevant. The results yielded inconsistent findings, suggesting that CYP2D6 and CYP2C19 testing may predict response in certain individuals, but it remains unclear if this will translate to improved clinical outcomes. Further research is required to determine when pharmacogenetic testing should be utilized and in which populations it is indicated. Randomized, controlled, prospective trials with adequate sample sizes would best clarify whether genotype-guided antidepressant selection will ultimately improve clinical outcomes.

The Three Ps: Psychiatry, Pharmacy, and Pharmacogenomics, a Brief Report From New Zealand

We describe a case series of 22 individuals who were referred to our laboratory by a pharmacist based in a mental health hospital, for pharmacogenetic analysis due to severe or unexpected adverse drug reactions (ADRs) to psychiatric medication. The participants were genotyped for common variation in the CYP2D6, CYP2C19, and CYP2C9 genes, using Sanger sequencing. We tested variants in these genes as they have the strongest evidence with respect to altering the pharmacokinetics of commonly prescribed psychiatric medicine. Looking specifically at the subset of 18 European study participants, we observed a comparatively high but non-significant rate of pharmacogenetic variants, compared to allele frequency surveys in unselected population samples. For CYP2D6, we observed an elevated frequency of both poor (17%) and intermediate (33%) metabolizers when compared with previously reported frequencies (6% and 12% respectively). For CYP2C19, we observed an increased frequency of intermediate (33%) and ultra-rapid (17%) metabolizers compared to expected frequencies (21% and 4% respectively). For CYP2C9, the frequency of intermediate metabolizers (22%) was elevated compared to the expected population frequency (11%). While sample size is a major limitation of this brief report, we can conclude that patients with adverse reactions to antidepressant or antipsychotic drugs selected by a specialist mental health pharmacist appear to have a relatively high rate of genetic variants in pharmacogenes known to affect the pharmacokinetics of these drugs. The selective application of such pharmacogenetic tests by clinical pharmacists may be a valuable approach to clarify the basis for adverse or unusual responses to medication, and to guide ongoing prescribing decisions for this group of patients.

Clinical implications of selective serotonin reuptake inhibitors-selective serotonin norepinephrine reuptake inhibitors pharmacogenetics during pregnancy and lactation

Depression occurs during pregnancy in 3.9–12.8% of the women. The different serotonin reuptake inhibitors (SRIs) are metabolized in the liver by CYP450 enzymes. CYP2D6 metabolizes paroxetine, fluoxetine, duloxetine and venlafaxine, while CYP2C19 deactivates citalopram and escitalopram. Polymorphisms in these enzymes change the metabolic clearance and levels of these drugs. Higher metabolism of most SRIs in late pregnancy results in lower maternal levels, which could result in decreased efficacy. Very few studies have addressed the potential interaction between pregnancy-induced increase in 2D6 metabolism and specific genotypes of the women, suggesting that ultra-rapid and extensive metabolizers exhibit lower serum concentrations than the other slower genotypes. Preliminary studies suggest that some genotypes of the serotonin transporter (SLC6A4) promoter are associated and are linked to adverse effects in infants with SRI exposure during pregnancy. Presently, there are no clear clinical implications of SRI pharmacogenetic status in pregnancy and lactation. In late pregnancy, women may exhibit lower steady state concentrations of these drugs, necessitating increased doses but these are presently guided clinically and not through genotyping. Much more work is needed to define whether SRI genotype has clinical implications and predictive value for either mother or offspring.