Anastasia S. Boiko

Identification of 5-hydroxytryptamine receptor gene polymorphisms modulating hyperprolactinaemia in antipsychotic drug-treated patients with schizophrenia

Abstract Objectives: Hyperprolactinaemia (HPRL) is a classical side effect of antipsychotic drugs primarily attributed to blockade of dopamine D2 subtype receptors in the pituitary gland. Although dopamine is considered the primary factor inhibiting prolactin release, the activity of prolactin-producing lactotrophs is also regulated by the secretagogues thyrotrophin releasing hormone, vasoactive intestinal polypeptide and serotonin (5-hydroxytryptamine; 5-HT). Methods: We describe the association between HPRL and a set of 29 SNPs from 5-HT receptor genes HTR1A, HTR1B, HTR2A, HTR2C, HTR3A, HTR3B and HTR6 in a population of 446 Caucasians (221 males/225 females) with a clinical diagnosis of schizophrenia (according to ICD-10: F20) who were treated with classical and/or atypical antipsychotic drugs. Results: None of the studied autosomal markers were found to be associated with HPRL. However, a significant association was established between various HTR2C polymorphisms and HPRL. Conclusions: This study revealed an association between HPRL and X-chromosome haplotypes comprised of the rs569959 and rs17326429 polymorphisms.

Cytochrome P450 1A2 co-determines neuroleptic load and may diminish tardive dyskinesia by increased inducibility

Abstract Objectives. The aim of this study was to investigate a possible association between tardive dyskinesia (TD) and CYP1A2 (*1F, -163C>А, rs762551) polymorphism in Russian psychiatric inpatients. Methods. TD was assessed cross-sectionally using the Abnormal Involuntary Movement Scale (AIMS). Orofacial and limb-truncal dyskinesia were assessed with AIMS 1–4 and 5–7, respectively. Standard protocols were applied for genotyping. Analysis of covariance (ANCOVA) was used to compare the mean AIMS scores for each of the genotypic classes. Results. A total of 319 Caucasian patients from West Siberia with schizophrenia and 117 healthy volunteers were investigated. No significant differences between the patients and the controls in genotype frequencies were found. Analysis of covariance (ANCOVA) with age, sex, duration of disease, chlorpromazine equivalent (CPZEQ) incorporated as covariates showed that limb-truncal, but not orofacial TD, is associated with CYP1A2 (−163C>, rs762551) polymorphism (F = 3.27, P = 0.039). Patients with the C/C genotype had a higher mean AIMS 5–7 score than those with the A/C or the A/A genotype. Conclusions. Our results support the hypothesis that not only with clozapine, but also with other classical and atypical antipsychotics, smoking may decrease plasma levels; this is most extensively expressed in carriers of the CYP1A2*1F (-163C> A) polymorphism.

Prolactin gene polymorphism (− 1149 G/T) is associated with hyperprolactinemia in patients with schizophrenia treated with antipsychotics

BACKGROUND Antipsychotic drugs can cause hyperprolactinemia. However, hyperprolactinemia was also observed in treatment-naive patients with a first schizophrenic episode. This phenomenon might be related to the role of prolactin as a cytokine in autoimmune diseases. Extrapituitary prolactin production is regulated by an alternative promoter, which contains the functional single nucleotide polymorphism -1149 G/T (rs1341239). We examined whether this polymorphism was associated with hyperprolactinemia in patients with schizophrenia. METHOD We recruited 443 patients with schizophrenia and 126 healthy controls. The functional polymorphism -1149 G/T (rs1341239) in the prolactin gene was genotyped with multiplexed primer extension, combined with MALDI-TOF mass spectrometry. Genotype and allele frequencies were compared between groups with the χ2 test and logistic regression models adjusting for covariates. RESULTS The frequency of genotypes and alleles in patients with schizophrenia did not differ from those in control subjects. A comparison between patients with schizophrenia with and without hyperprolactinemia revealed significantly higher frequency of the G allele in patients with hyperprolactinemia than in patients without it (χ2=7.25; p=0.007; OR=1.44 [1.10-1.89]). Accordingly, patients with hyperprolactinemia carried the GG genotype more frequently than patients without hyperprolactinemia (χ2=9.49; p=0.009). This association remained significant after adjusting the estimates for such covariates as sex, age, duration of the diseases and the dose of chlorpromazine equivalents. CONCLUSION This study revealed a significant association between the polymorphic variant rs1341239 and the development of hyperprolactinemia in patients with schizophrenia. The serum prolactin concentration in patients with schizophrenia treated with antipsychotics may provide an indication of the activity of the gene that regulates extrapituitary prolactin production which is believed to play a role in the immune system.

Potential biomarkers of tardive dyskinesia: A multiplex analysis of blood serum

Potential biomarkers of tardive dyskinesia: a multiplex analysis of blood serum A.S. Boiko(1), E.G. Kornetova(2), S.A. Ivanova(1), A.J.M. Loonen(3) (1)Mental Health Research Institute, Tomsk National Research Medical Center of the Russian Academy of Sciences, Laboratory of Molecular Genetics and Biochemistry, Tomsk, Russia (2)Mental Health Research Institute, Tomsk National Research Medical Center of the Russian Academy of Sciences, Department of Endogenous Disorders, Tomsk, Russia (3)University of Groningen, Groningen Research Institute of Pharmacy, Groningen, The Netherlands Long-term antipsychotic treatment of schizophrenia is associated with the emergence of tardive dyskinesia (TD), a motor syndrome consisting of involuntary and hyperkinetic movements [1]. Pathogenesis of this drug-induced movement disorder is not yet fully established, but may be connected to oxidative stress-related indirect pathway neurotoxicity [2]. Dysregulations in immune, hormonal and neurotrophic systems have been postulated to be one of the mechanisms underlying this form of neurotoxicity [3,4]. Principle aims of translational psychiatric research are searching for biomarkers which can be used to diagnose pathological biochemical processes and to identify molecular targets for treatment as well as development of pharmacogenetic approaches to personalize this therapy. The aim is to study potential endocrine, neurotrophic and immunological markers of tardive dyskinesia in the blood serum of patients with schizophrenia with antipsychotic therapy. Methods: After obtaining approval of the study protocol by the local ethical committee, suitable participants were recruited from psychiatric hospitals. All subjects gave informed consent after proper explanation of the study. TD was assessed cross-sectionally by the use of the Abnormal Involuntary Movement Scale (AIMS) [1,5]. The concentrations of cortisol, brain-derived neurotrophic factor (BDNF), prolactin, cytokines (tumor necrosis factor (TNFa), interleukin 1 (IL-1β), interleukin 3 (IL-3), interleukin 6 (IL-6), interferon gamma (INF-γ) and S100β were measured in blood serum using the MILLIPLEX® MAP panels (Merck, Darmstadt, Germany) by the multiplex analyzer MAGPIX (Luminex, USA). Statistical analyses were performed using SPSS software for Windows. Results were expressed as median and quartile intervals (Me [Q1; Q3]) or mean and standard deviation (M ± SD). Differences were considered significant at p ≤ 0.05. Results: In total 180 patients with schizophrenia, 128 males and 52 females (age 39.2 ± 12.1 years), receiving long-term antipsychotic treatment were included. These patients were divided into two groups: 71 patients with tardive dyskinesia and 109 patients without this movement disorder. A significant (p = 0.04) decrease in BDNF concentration was observed in patients with TD (1.9 [1.01; 2.99] ng/ml) in comparison to patients without TD (2.66 [1.29; 3.89] ng/ml). An increase (p = 0.05) of the serum IL-6 level of patients with TD (5.69 [3.55; 7.4] pg/ml) was detected relative to patients without TD (4.69 [2.82; 6.13] pg/ml). In addition, a statistical trend (p = 0.06) of increased serum S100β concentration was found in TD patients (85.29 ± 5.53 ng/L) compared to patients without this side effect (75.14 ± 2.81 ng/L). No other significant differences were established concerning the other assayed biomarkers. Conclusions: The biological processes that might play a role in the development of TD are not confined to the human brain per se. Hormonal and immune systems are also involved, which may be related to these systems being closely interrelated. Furthermore, these parameters may provide information about risk factors of the movement disorder. Identifying markers that can be used as diagnostics or predictors of treatment response in people with tardive dyskinesia will be an important step towards being able to provide personalized treatment. References [1] Loonen, A.J., van Praag, H.M., 2007. Measuring movement disorders in antipsychotic drug trials: the need to define a new standard. J Clin Psychopharmacol 27, 423–430. [2] Loonen, A.J.M., Ivanova, S.A., 2013. New insights into the mechanism of druginduced dyskinesia. CNS Spectrums 18 (01), 15–20. [3] Wu, J.Q., Chen, D.Ch., Tan, Yu.L., Tan, Sh.P., Hui, L., Lv, M.H., Soares, J.C., Zhang, X.Y., 2015. Altered BDNF is correlated to cognition impairment in schizophrenia patients with tardive dyskinesia. Psychopharmacology 232, 223–232. [4] An, H.M., Tan, Y.L., Shi, J., Wang, Z.R., Soars, J.C., Wu, J.Q., Yang, F.D., Huang, X.F., Zhang, X.Y., 2015. Altered IL-2, IL-6 and IL-8 serum levels in schizophrenia patients with tardive dyskinesia. Schizophr Res 162 (1–3), 261–268. [5] Loonen, A.J.M., Doorschot, C.H., van Hemert, D.A., Oostelbos, M.C., Sijben, A.E., 2001. The schedule for the assessment of drug-induced movement disorders (SADIMoD): inter-rater reliability and construct validity. Int J Neuropsychopharmacol 4, 347–360. Keywords: Biological markers Schizophrenia: clinical Neuroleptics & antipsychotics: clinical

Association between P-glycoprotein polymorphisms and antipsychotic drug-induced hyperprolactinemia

Background: Regular therapy for schizophrenia includes maintenance antipsychotic treatment. Unfortunately, antipsychotics also have a spectrum of side effects, including metabolic, endocrine, cardiovascular, and movement disorders. One of the common side effects of these drugs is hyperprolactinemia (HPRL) [1]. This side effect is attributed to blockade of dopamine D2 receptors on the membranes of lactotroph cells within the pituitary gland. Certain antipsychotic drugs, e.g. risperidone, are more likely to induce HPRL because of relative accumulation within the adenohypophysis. The strong prolactin-elevating effect of risperidone reflects its relatively high blood/brain concentration ratio, a consequence of it being a substrate for the p-glycoprotein (P-gp, also known as ABCB1) pump [2]. Therefore, P-gp genotypes with altered functional activity might influence the potential of risperidone to cause HPRL as the changed blood/brain concentration ratio would lead to an altered vulnerability for CNS side effects like parkinsonism. Such side effects are expected to make dose adaptations necessary, which would also decrease exposure of lactrotroph dopamine D2 receptors. Aims: The present study aimed to investigate the influence of polymorphisms of the P-glycoprotein gene (ABCB1 gene) on the prevalence of antipsychotic-induced hyperprolactinemia in patients with schizophrenia. Methods: We studied the association between polymorphisms of the P-gp gene (ABCB1 gene) and antipsychotic drug-induced hyperprolactinemia in patients with schizophrenia from Siberia. Evaluation of serum prolactin was performed by ELISA using reagents set PRL Test System (USA). Genotyping was carried out on 8 polymorphic variants of the P-glycoprotein gene (rs1045642, rs2032582, rs4148739, rs28401781, rs2235040, rs9282564, rs2235015, and rs2032583). Associations between HPRL and polymorphisms of P-gp gene were established using logistic regression accounting for covariates (age, sex, duration of the disease, and CPZeq). An additive genetic model was tested and the analysis was carried out both in the total sample and in subgroups stratified by the use of risperidone/paliperidone (N = 76) or sulpiride/amisulpride (N = 13). Bonferroni correction was applied assuming 5 independent tests estimated via the correlation between the SNPs. Results: 446 Russian patients with schizophrenia were examined, including 225 women and 221 men [3]. The average age of patients was 42.1 ± 1.4 years. No statistically significant associations were obtained in the total sample after correction for multiple-testing. However, the rs2032582 variant appeared to be protective against HPRL in the subgroup of patients using risperidone or paliperidone (OR = 0.17, 95% CI = 0.04–0.79, adjusted p = 0.041). Discussion: Our finding supports the hypothesis that a variant of P-gp gene may influence the likelihood of inducing HPRL in patients using risperidone or paliperidone (i.e. 9-hydroxy-risperidone). This may be related to affecting the blood/brain concentration ratio of the risperidone moiety. In the total sample the association was significant but did not survive correction for multiple testing. Moreover, another variant, rs4148739, was associated to a larger extent than rs2032582. Hence, the variant may affect the affinity of the risperidone moiety specifically without having consequences for the binding and transport of other antipsychotic drugs. Conclusion: Rs2032582 of the P-gp is negatively associated with risperidone/paliperidone-induced HPRL, but not with HPRL induced by other antipsychotic drugs. References [1] Peuskens, J., Pani, L., Detraux, J., De Hert, M., 2014. The effects of novel and newly approved antipsychotics on serum prolactin levels: a comprehensive review. CNS Drugs 28, 421–453. [2] Ejsing, T., Pedersen, A., Linnet, K., 2005. P-glycoprotein interaction with risperidone and 9-OH-risperidone studied in vitro, in knock-out mice and in drug-drug interaction experiments. Hum Psychopharmacol 20, 493–500. [3] Ivanova, S.A., Osmanova, D.Z., Freidin, M.B., Fedorenko, O.Y., Boiko, A.S., Pozhidaev, I.V., Semke, A.V., Bokhan, N.A., Agarkov, A.A., Wilffert, B., Loonen, A.J.M., 2017. Identification of 5-hydroxytryptamine receptor gene polymorphisms modulating hyperprolactinaemia in antipsychotic drug-treated patients with schizophrenia. World J Biol Psychiatry 18, 239–246. Keywords: Schizophrenia: clinical Pharmacokinetics Neuroendocrinology

[The association of the DRD3 gene with Parkinson's disease].

OBJECTIVE To investigate the association between dopamine receptor DRD3 gene tag single nucleotide polymorphisms (SNPs) and the risk of Parkinsons disease (PD). MATERIAL AND METHODS One hundred and forty-three patients with PD and 96 healthy individuals from the Russian population were examined. Ten tag SNPs (rs963468, rs2134655, rs9817063, rs324035, rs11721264, rs1800828, rs3773678, rs167770, rs167771, rs7633291) within DRD3 have been genotyped. RESULTS AND CONCLUSION Associations between 4 polymorphisms (rs11721264, rs3773678, rs167771, rs324035) and PD have been found. Our study confirms the involvement of polymorphic features of dopamine receptors genes in the pathophysiology in PD.

Gene polymorphism of neurotransmitter transporters in schizophrenic patients with drug-induced hyperprolactinemia

The regular therapy of schizophrenia includes a maintenance antipsychotic treatment, which improves the long-term prognosis of the disease [2]. Unfortunately antipsychotics also have a spectrum of side effects, including metabolic, endocrine and movement disorders [3,4]. One of the common side effects of these drugs is hyperprolactinemia (HP) [1]. The results of pharmacogenetic studies aimed at prognostic evaluation of the safe use of antipsychotics are the most persuasive. The components of dopamine, serotonin and norepinephrine neurotransmission in schizophrenia are considered as the main target for the action of antipsychotics. The present study aims to elucidate the role of 12 SNPs of dopamine transporter gene SLC6A3, 9 SNPs of norepinephrine transporter gene SLC6A2 and polymorphism of vesicular monoamine transporter gene SLC6A2 in the pathogenesis of antipsychotic-induced hyperprolactinemia in patients with schizophrenia. A total of 445 ethnic Russian patients from Siberia regions were studied, including 224 women and 221 men with a diagnosis of paranoid schizophrenia (the mean age - 42.1±1.4 years). Prolactin level was analyzed using the AccuBind ELISA Microwells kit (Monobind Inc., USA). Genotyping of SNPs was done with The MassARRAY® Analyzer 4 by Agena Bioscience™, using SEQUENOM. Statistical analysis was performed using the SPSS program. The Hardy-Weinberg equilibrium and differences in genotype frequencies were tested using a chi-square test. Differences were considered significant at p

Gene polymorphism of serotonin receptors and drug-induced hyperprolactinemia in schizophrenic patients

Background: Antipsychotics have been used for more than 50 years in the treatment of schizophrenia and many other psychiatric disorders. Schizophrenic patients have to take antipsychotic medication for a long time, often throughout the life [1]. Hyper prolactinemia in these patients is a common and serious side effect of therapy with atypical antipsychotics. Genes coding for serotonin receptors are considered as candidate genes responsible for the particular antipsychotic effects of neuroleptics [2]. The present study aimed to investigate the role of polymorphisms of the serotonin receptors genes (HTR1A, HTR1B, HTR2A, HTR2C, HTR3A, HTR3B, HTR6) in the pathogenesis of antipsychotic-induced hyperprolactinemia in patients with schizophrenia. Methods: 446 Russian patients with schizophrenia were examined, including 225 women and 221 men. The average age of patients was 42.1±1.4 years. Evaluation of serum prolactin performed by ELISA using reagents set PRL Test System (USA). Genotyping was carried out on 29 polymorphic variants of the serotonin receptor genes HTR1A (rs6295, rs1364043, rs10042486, rs1800042, rs749099), HTR1B (rs6298, rs6296, rs130058), HTR2A (rs6311, rs6313, rs6314, rs7997012, rs1928040, rs9316233, rs2224721, rs6312), HTR2C (rs6318, rs5946189, rs569959, rs17326429, rs4911871, rs3813929, rs1801412, rs12858300), HTR3A (rs1062613, rs33940208, rs1176713), HTR3B (rs1176744) and HTR6 (rs1805054). The SPSS software was used for statistical analysis. The Hardy-Weinberg equilibrium (HWE) of genotypic frequencies was tested by the chi-square test. Results: We studied the association between polymorphisms of relevant 5-HT receptor genes and antipsychotic drug-induced hyperprolactinemia in patients with schizophrenia from Siberia. All patients with schizophrenia were divided into two groups: those with and without hyperprolactinemia. Statistically significant results were obtained for polymorphic variants of the genes rs6312 HTR2A (χ2 = 4.685; p = 0.030), rs12858300 HTR2C, rs569959 HTR2C, which suggests the participation of these polymorphic variants in the development of hyperprolactinemia. When men and women were studied separately, only rs569959 HTR2C (χ2 = 6.284; p = 0.043) in men reached the nominal significance threshold. This finding is probably related to the X-bound character of HTR2C (i.e., men are hemizygotes). Also, we found a statistically significant association rs12858300 HTR2C (χ2 = 9.429; p = 0.002) in the female group. We did not find statistically significant association for other polymorphisms HTR1A (rs6295, rs1364043, rs10042486, rs1800042, rs749099), HTR1B (rs6298, rs6296, rs130058), HTR2A (rs6311, rs6313, rs6314, rs7997012, rs1928040, rs9316233, rs2224721), HTR2C (rs6318, rs5946189, rs17326429, rs4911871, rs3813929, rs1801412), HTR3A (rs1062613, rs33940208, rs1176713), HTR3B (rs1176744) and HTR6 (rs1805054). Though hyperprolactinemia is primarily attributed to blockade of DRD2 in the pituitary gland, the secretion of prolactin is also modulated by 5-HT. The involvement of the HTR1A, HTR2A, HTR2C, and HTR3 in the serotonergic-induced prolactin response is well documented. Conclusion: Our results indicate that genetic variants of HTR2C may have functional consequences on the modulation of prolactin secretion. Further search for genetic markers associated with the development of side effects of neuroleptic therapy, will contribute to the development of effective methods of diagnosis, correction and treatment of disease, as well as of adherence of patients with mental disorders to psychotropic therapy.