Female-specific regulation of cytochrome P450 3As and their response to xenobiotic stress

Cytochrome P450 3As (CYP3As) are phase I enzymes responsible for metabolizing more than 50% of clinical drugs. Recent studies have revealed that expression of CYP3As is two-fold higher in women than in men leading to a faster metabolic clearance of therapeutic drugs in women. In this study, we analyzed the female specific rat CYP3A isoform, CYP3A9. We evaluated the effects of progesterone and estrogen on CYP3A9 regulation and showed a distinct role for estrogen in mediating female dominance of CYP3A9. We also observed changes in CYP3A9 expression at various stages of pregnancy which correlates well with varying physiological estradiol concentrations. In addition, by the in vitro data shows that estradiol mediated induction can be abrogated with estrogen receptor antagonist ICI182,780. We also identified three novel murine CYP3A isoforms CYP3A13, CYP3A41 and CYP3A44 and characterized their genomic structures and expression profiles. CYP3A41 and CYP3A44 show female specific expression but surprisingly this female dominance is not mediated via estrogen. Control male mice did not exhibit any CYP3A41 mRNA levels but showed minimal levels of CYP3A44. In order to gain insights into the governance ofαthe female specific genes, the hepatic regulation of CYP3A41 and CYP3A44 by the xeno-sensors PXR and CAR was examined. In female mice, pregnenolone-16α-carboxynitrile, suppressed CYP3A41 and CYP3A44 mRNA levels in PXR−/− background whereas dexamethasone-dependent suppression of CYP3A41 was mediated by PXR. In addition, phenobarbital challenge in PXR−/− revealed up-regulation of both CYP3A44, CYP3A41 levels only in males. No role for CAR was seen in the regulation of either CYP3A41 or CYP3A44 gene expression in female mice. Interestingly, PXR and CAR ligands induced male CYP3A44 levels in a receptor dependent fashion. This increase of CYP3A44 transcript in male mice is in contrast to the response seen in female mice, which clearly indicates an additional layer of regulation. Our findings suggest that gender plays a strategic role in directing the CAR/PXR mediated effects of CYP3A44/CYP3A41. This implies that differential regulation of female specific CYP3A isoforms may be the key to explain some of the gender differences observed in clearance of certain therapeutics like antidepressants and analgesics. ^

The association between maternal use of selective serotonin reuptake inhibitors during pregnancy and adverse pregnancy outcomes

Maternal use of SSRIs for depression and anxiety during pregnancy has increased over the last decade. Recent studies have questioned the safety of these antidepressants when used in during pregnancy. The aim of this project is to assess the associations between maternal SSRI use and GH, SGA, and preterm birth using data from a U.S. population-based study with self-reported exposure information. ^ The study population is comprised of mothers of control infants from the NBDPS, an ongoing, multi-state, population-based case-control study. Mothers were asked about any use of medications during pregnancy, including the dates they started and stopped taking each medication. Maternal GH was self-reported, while gestational age and birth weight were calculated from information on birth certificates or medical records. ^ Our study found that women exposed to SSRIs in the first trimester and beyond had a higher odds of GH compared to unexposed women (aOR=1.96, 95% CI=1.02-3.74). Women who used SSRIs only in the first trimester had no increased odds of GH (aOR=0.77, 95% CI=0.24-2.50). Women who used SSRIs throughout their entire pregnancy had a two-fold increase in the odds of delivering an SGA infant compared to unexposed women (aOR=2.16, 95% CI=1.01-4.62), while women who reported SSRI use only in the first trimester had a decreased odds of delivering an SGA infant (aOR=0.56, 95% CI=0.14-2.34). Finally, both women who used SSRIs in the first trimester only (aOR=1.58, 95% CI=0.71-3.51) and women who used SSRIs in the first trimester and beyond (aOR=1.49, 95% CI=0.76-2.90) had an increased odds of delivering preterm compared to unexposed women. ^ Results from our study suggest that women who use SSRIs in the first trimester and beyond have an increased and significant odds of GH and SGA. An increase in the odds of preterm birth was also observed among women exposed in this period and is consistent with the results of previous studies which had much larger sample sizes. Women who use SSRIs only in the first trimester appear to have no increased odds of GH or SGA, but may have an increased odds of preterm birth. These findings are consistent with previous studies and highlight how exposure to SSRIs at different points in gestation may result in different risks for these outcomes. ^

Occurrence and analysis of selected pharmaceutical compounds in soil from Spanish agricultural fields

This work describes the analysis of 15 pharmaceutical compounds, belonging to different therapeutic classes (anti-inflammatory/analgesics, lipid regulators, antiepileptics, ?-blockers and antidepressants) and with diverse physical?chemical properties, in Spanish soils with different farmland uses. The studied compounds were extracted from soil by ultrasound-assisted extraction (UAE) and determined, after derivatization, by gas chromatography with mass spectrometric detection (GC?MS). The limits of detection (LODs) ranged from 0.14 ng g?1 (naproxen) to 0.65 ng g?1 (amitriptyline). At least two compounds where detected in all samples, being ibuprofen, salicylic acid, and paracetamol, the most frequently detected compounds. The highest levels found in soil were 47 ng g?1 for allopurinol and 37 ng g?1 for salicylic acid. The influence of the type of crop and the sampling area on the levels of pharmaceuticals in soil, as well as their relationship with soil physical?chemical properties, was studied. The frequent and widespread detection of some of these compounds in agricultural soils show a diffuse contamination, although the low levels found do not pose a risk to the environment or the human health.

Patch-clamp and amperometric recordings from norepinephrine transporters: Channel activity and voltage-dependent uptake

Transporters for the biogenic amines dopamine, norepinephrine, epinephrine and serotonin are largely responsible for transmitter inactivation after release. They also serve as high-affinity targets for a number of clinically relevant psychoactive agents, including antidepressants, cocaine, and amphetamines. Despite their prominent role in neurotransmitter inactivation and drug responses, we lack a clear understanding of the permeation pathway or regulation mechanisms at the single transporter level. The resolution of radiotracer-based flux techniques limits the opportunities to dissect these problems. Here we combine patch-clamp recording techniques with microamperometry to record the transporter-mediated flux of norepinephrine across isolated membrane patches. These data reveal voltage-dependent norepinephrine flux that correlates temporally with antidepressant-sensitive transporter currents in the same patch. Furthermore, we resolve unitary flux events linked with bursts of transporter channel openings. These findings indicate that norepinephrine transporters are capable of transporting neurotransmitter across the membrane in discrete shots containing hundreds of molecules. Amperometry is used widely to study neurotransmitter distribution and kinetics in the nervous system and to detect transmitter release during vesicular exocytosis. Of interest regarding the present application is the use of amperometry on inside-out patches with synchronous recording of flux and current. Thus, our results further demonstrate a powerful method to assess transporter function and regulation.

A single serine residue controls the cation dependence of substrate transport by the rat serotonin transporter

The serotonin transporter (SERT) is a member of the Na+/Cl−-dependent neurotransmitter transporter family and constitutes the target of several clinically important antidepressants. Here, replacement of serine-545 in the recombinant rat SERT by alanine was found to alter the cation dependence of serotonin uptake. Substrate transport was now driven as efficiently by LiCl as by NaCl without significant changes in serotonin affinity. Binding of the antidepressant [3H]imipramine occurred with 1/5th the affinity, whereas [3H]citalopram binding was unchanged. These results indicate that serine-545 is a crucial determinant of both the cation dependence of serotonin transport by SERT and the imipramine binding properties of SERT.

Estrogen alters behavior and forebrain c-fos expression in ovariectomized rats subjected to the forced swim test

Estrogen has been implicated in brain functions related to affective state, including hormone-related affective disorders in women. Although some reports suggest that estrogen appears to decrease vulnerability to affective disorders in certain cases, the mechanisms involved are unknown. We used the forced swim test (FST), a paradigm used to test the efficacy of antidepressants, and addressed the hypotheses that estrogen alters behavior of ovariectomized rats in the FST and the FST-induced expression of c-fos, a marker for neuronal activity, in the rat forebrain. The behaviors displayed included struggling, swimming, and immobility. One hour after the beginning of the test on day 2, the animals were perfused, and the brains were processed for c-fos immunocytochemistry. On day 1, the estradiol benzoate-treated animals spent significantly less time struggling and virtually no time in immobility and spent most of the time swimming. Control rats spent significantly more time struggling or being immobile during a comparable period. On day 2, similar behavioral patterns with still more pronounced differences were observed between estradiol benzoate and ovariectomized control groups in struggling, immobility, and swimming. Analysis of the mean number of c-fos immunoreactive cell nuclei showed a significant reduction in the estradiol benzoate versus control groups in areas of the forebrain relating to sensory, contextual, and integrative processing. Our results suggest that estrogen-induced neurochemical changes in forebrain neurons may translate into an altered behavioral output in the affective domain.

Depression as a risk factor for ischaemic heart disease in men: population based case-control study

Objective: To determine the relation between depression, anxiety, and use of antidepressants and the onset of ischaemic heart disease.

Antidepressant Use and Risk of Dementia and Cognitive Decline

Thesis (Ph.D.)--University of Washington, 2016-06

Roles of transmembrane domain 2 and the first intracellular loop in human noradrenaline transporter function: pharmacological and SCAM analysis

The aim was to investigate the roles of transmembrane domain 2 and the adjacent region of the first intracellular loop in determining human noradrenaline transporter (hNET) function by pharmacological and substituted-cysteine accessibility method (SCAM) analyses. It was first necessary to establish a suitable background NET for SCAM. Alanine mutants of endogenous hNET cysteines, hC86A, hC131A and hC339A, were examined and showed no marked effects on expression or function. hNET and the mutants were also resistant to methanethiosulfonate (MTS), ethylammonium (MTSEA) and MTStrimethylammonium (MTSET). Hence, wild-type hNET is an appropriate background for production of cysteine mutants for SCAM. Pharmacological investigation showed that all mutants except hT99C and hL109C showed reduced cell-surface expression, while all except hM107C showed a reduction in functional activity. The mutations did not markedly affect the apparent affinities of substrates, but apparent affinities of cocaine were decreased 7-fold for hP97C and 10-fold for hF101C and increased 12-fold for hY98C. [H-3]Nisoxetine binding affinities were decreased 13-fold for hP97C and 5-fold for hF101C. SCAM analysis revealed that only hL102C was sensitive to 1.25 mM MTSEA, and this sensitivity was protected by noradrenaline, nisoxetine and cocaine. The results suggest that this region of hNET is important for interactions with antidepressants and cocaine, but it is probably not involved in substrate translocation mechanisms.

Cost-effectiveness of cognitive-behavioural therapy and drug interventions for major depression

Objective: Antidepressant drugs and cognitive-behavioural therapy (CBT) are effective treatment options for depression and are recommended by clinical practice guidelines. As part of the Assessing Cost-effectiveness - Mental Health project we evaluate the available evidence on costs and benefits of CBT and drugs in the episodic and maintenance treatment of major depression. Method: The cost-effectiveness is modelled from a health-care perspective as the cost per disability-adjusted life year. Interventions are targeted at people with major depression who currently seek care but receive non-evidence based treatment. Uncertainty in model inputs is tested using Monte Carlo simulation methods. Results: All interventions for major depression examined have a favourable incremental cost-effectiveness ratio under Australian health service conditions. Bibliotherapy, group CBT, individual CBT by a psychologist on a public salary and tricyclic antidepressants (TCAs) are very cost-effective treatment options falling below $A10 000 per disability-adjusted life year (DALY) even when taking the upper limit of the uncertainty interval into account. Maintenance treatment with selective serotonin re-uptake inhibitors (SSRIs) is the most expensive option (ranging from $A17 000 to $A20 000 per DALY) but still well below $A50 000, which is considered the affordable threshold. Conclusions: A range of cost-effective interventions for episodes of major depression exists and is currently underutilized. Maintenance treatment strategies are required to significantly reduce the burden of depression, but the cost of long-term drug treatment for the large number of depressed people is high if SSRIs are the drug of choice. Key policy issues with regard to expanded provision of CBT concern the availability of suitably trained providers and the funding mechanisms for therapy in primary care.

Quantitative analysis of immunolabeling for serotonin and for glutamate transporters after administration of imipramine and citalopram

Serotonin (5-hydroxytryptamine, 5-HT) is an amine neurotransmitter derived from tryptophan and is important in brain systems regulating mood, emotional behavior, and sleep. Selective serotonin reuptake inhibitor (SSRI) drugs are used to treat disorders such as depression, stress, eating disorders, autism, and schizophrenia. It is thought that these drugs act to prolong the action of 5-HT by blocking reuptake. This may lead to decreased 5-HT content in the nerve fibers themselves; however, this has not previously been directly demonstrated. We have studied the effects of administration of two drugs, imipramine and citalopram, on levels of 5-HT in nerve fibers in the murine brain. Quantitative analysis of the areal density of 5-HT fibers throughout the brain was performed using ImageJ software. While a high density of fibers was observed in mid- and hind-brain regions and areas such as thalamus and hypothalamus, densities were far lower in areas such as cortex, where SSRIs might be thought to exert their actions. As anticipated, imipramine and citalopram produced a decline in 5-HT levels in nerve fibers, but the result was not uniform. Areas such as inferior colliculus showed significant reduction whereas little, if any, change was observed in the adjacent superior colliculus. The reason for, and significance of, this regionality is unclear. It has been proposed that serotonin effects in the brain might be linked to changes in glutamatergic transmission. Extracellular glutamate levels are regulated primarily by glial glutamate transporters. Qualitative evaluation of glutamate transporter immunolabeling in cortex of control and drug-treated mice revealed no discernable difference in intensity of glutamate transporter immunoreactivity. These data suggest that changes in intracellular and extracellular levels of serotonin do not cause concomitant changes in astroglial glutamate transporter expression, and thus cannot represent a mechanism for the delayed efficacy of antidepressants when administered clinically. © 2005 Elsevier B.V. All rights reserved.

Number and type of substances in alcohol and drug-related completed suicides in an Australian sample

Background: The association between substance use and suicide is well-established, but evidence is scant regarding the relationship between the number, type, and level of substances and other risk factors in completed suicide across the lifespan. Aims: To examine the relationship between social/demographic characteristics and the number, type, and level of drugs present in an unrestricted age sample of completed suicides in Australia. Method: An analysis was undertaken of 893 substance-related suicides using data from the Government Statistician's Office for the years 1989-1992. Results: The number and type of substances present in suicide victims was related to the individual's gender, age, marital status, employment status, and method of suicide. Blood alcohol level was significantly different between the methods of suicide, but was unrelated to demographic characteristics of the individual. The level of antidepressants and minor tranquilizers in the individuals was also unrelated to demographic characteristics. Conclusion: Examination of the type and number of substances present in completed suicides is an important component in creating profiles of potential suicide victims.

Psychotropic medication utilization in a child and adolescent mental health service

Objectives: This study aimed to identify rates and correlates of psychotropic drug utilization in children and adolescents in inpatient and outpatient settings. Methods: A retrospective chart review examined 122 inpatient and 126 outpatient charts from a metropolitan child and youth mental health service in Brisbane, Australia. Results: Inpatients received more psychotropic medication than outpatients (71% vs. 25%; p < 0.01). Patients receiving medication were older, had longer hospital admissions, and more complex presentations, including history of abuse or suicide attempts and more diagnoses (all p < 0.01). Selective serotonin reuptake inhibitors (SSRIs) were the most frequently used drug class (44% inpatients; 14% outpatients), primarily indicated for mood disorders (31%). SSRIs and newer antidepressants (ADs) were used more frequently in patients with a high suicide risk (p < 0.01). Atypical antipsychotics (APs) were also used (inpatients 23%; outpatients 3%), primarily for behavioral disturbances. Half of those receiving medication (51%) received polypharmacy (> 1 concurrent drug), with up to four drugs used at one time. Rates of polypharmacy were highest among patients receiving antipsychotics. Conclusions: Use of psychotropic medication is frequent in this population. Future research should initially focus on inpatients and intensive treatment settings and examine both safety and efficacy of interventions for depression in young people, atypical antipsychotics for behavioral disturbances, and polypharmacy.

Herbal medicines:physician's recommendation and clinical evaluation of St.John's Wort for depression

Why some physicians recommend herbal medicines while others do not is not well understood. We undertook a survey designed to identify factors, which predict recommendation of herbal medicines by physicians in Malaysia. About a third (206 out of 626) of the physicians working at the University of Malaya Medical Centre ' were interviewed face-to-face, using a structured questionnaire. Physicians were asked about their personal use of, recommendation of, perceived interest in and, usefulness and safety of herbal medicines. Using logistic regression modelling we identified personal use, general interest, interest in receiving training, race and higher level of medical training as significant predictors of recommendation. St. John's wort is one of the most widely used herbal remedies. It is also probably the most widely evaluated herbal remedy with no fewer than 57 randomised controlled trials. Evidence from the depression trials suggests that St. John's wort is more effective than placebo while its comparative efficacy to conventional antidepressants is not well established. We updated previous meta-analyses of St. John's wort, described the characteristics of the included trials, applied methods of data imputation and transformation for incomplete trial data and examined sources of heterogeneity in the design and results of those trials. Thirty randomised controlled trials, which were heterogeneous in design, were identified. Our meta-analysis showed that St. John's wort was significantly more effective than placebo [pooled RR 1.90 (1.54-2.35)] and [Pooled WMD 4.09 (2.33 to 5.84)]. However, the remedy was similar to conventional antidepressant in its efficacy [Pooled RR I. 0 I (0.93 -1.10)] and [Pooled WMD 0.18 (- 0.66 to 1.02). Subgroup analyses of the placebo-controlled trials suggested that use of different diagnostic classifications at the inclusion stage led to different estimates of effect. Similarly a significant difference in the estimates of efficacy was observed when trials were categorised according to length of follow-up. Confounding between the variables, diagnostic classification and length of trial was shown by loglinear analysis. Despite extensive study, there is still no consensus on how effective St. lohn's wort is in depression. However, most experts would agree that it has some effect. Our meta-analysis highlights the problems associated with the clinical evaluation of herbal medicines when the active ingredients are poorly defined or unknown. The problem is compounded when the target disease (e.g. depression) is also difficult to define and different instruments are available to diagnose and evaluate it.

Abnormal left and right amygdala-orbitofrontal cortical functional connectivity to emotional faces:state versus trait vulnerability markers of depression in bipolar disorder

Background - Amygdala-orbitofrontal cortical (OFC) functional connectivity (FC) to emotional stimuli and relationships with white matter remain little examined in bipolar disorder individuals (BD). Methods - Thirty-one BD (type I; n = 17 remitted; n = 14 depressed) and 24 age- and gender-ratio-matched healthy individuals (HC) viewed neutral, mild, and intense happy or sad emotional faces in two experiments. The FC was computed as linear and nonlinear dependence measures between amygdala and OFC time series. Effects of group, laterality, and emotion intensity upon amygdala-OFC FC and amygdala-OFC FC white matter fractional anisotropy (FA) relationships were examined. Results - The BD versus HC showed significantly greater right amygdala-OFC FC (p = .001) in the sad experiment and significantly reduced bilateral amygdala-OFC FC (p = .007) in the happy experiment. Depressed but not remitted female BD versus female HC showed significantly greater left amygdala-OFC FC (p = .001) to all faces in the sad experiment and reduced bilateral amygdala-OFC FC to intense happy faces (p = .01). There was a significant nonlinear relationship (p = .001) between left amygdala-OFC FC to sad faces and FA in HC. In BD, antidepressants were associated with significantly reduced left amygdala-OFC FC to mild sad faces (p = .001). Conclusions - In BD, abnormally elevated right amygdala-OFC FC to sad stimuli might represent a trait vulnerability for depression, whereas abnormally elevated left amygdala-OFC FC to sad stimuli and abnormally reduced amygdala-OFC FC to intense happy stimuli might represent a depression state marker. Abnormal FC measures might normalize with antidepressant medications in BD. Nonlinear amygdala-OFC FC–FA relationships in BD and HC require further study.