Ayako Kaneda

Association between multidrug resistance 1 (MDR1) gene polymorphisms and therapeutic response to bromperidol in schizophrenic patients : A preliminary study

The drug-transporting P-glycoprotein transports drugs against a concentration gradient across the blood-brain barrier back into the plasma and thereby reduces the bioavailability in the brain. Polymorphisms in the MDR1 gene regulating P-glycoprotein expression can be associated with differences in drug disposition in the brain. The present study was therefore designed to examine whether the major polymorphisms of MDR1 gene, C3435T and G2677T/A are related to therapeutic response to neuroleptics in the treatment of schizophrenia. Subjects consisted of 31 acutely exacerbated schizophrenic inpatients treated with bromperidol (6-18 mg/day). Plasma drug concentrations were monitored and clinical symptoms were evaluated using the Brief Psychiatric Rating Scale (BPRS) before and 3 weeks after the treatment. The C3435T and G2677T/A genotypes were determined by a polymerase chain reaction method. Schizophrenic symptoms were allocated into 5 clusters: positive, excitement, cognitive, negative, and anxiety-depression symptoms. Patients were C/C in 12, C/T in 12 and T/T in 7 cases for C3435T genotype and G/G in 3, G/T or A in 17 and T or A/T or A in 11 cases for G2677T/A genotype. There were a tendency of difference, but not statistically different, in the percentage improvement or the improved scores of 5 sub-grouped symptoms after the 3-week treatment between C3435T genotypes and between G2677T/A genotypes. Multiple regression analyses including age, body weight, gender and drug concentration showed significant correlations between the percentage improvement and the improved scores of cognitive symptoms and C3435T genotypes. The present results suggest that the C3435T polymorphism is associated with some therapeutic response to bromperidol in schizophrenic patients, possibly by different drug concentration in the brain.

The effects of Ginkgo biloba extracts on the pharmacokinetics and pharmacodynamics of donepezil.

The effects of ginkgo supplementation on the steady‐state plasma concentration of donepezil and the activity of cholinesterase in red blood cells and cognitive function were examined. Fourteen inpatients with Alzheimers disease received donepezil 5 mg/day, supplemented with extracts of Ginkgo biloba 90 mg/day for 30 days. Blood samples were collected before and during ginkgo supplementation and 30 days after its discontinuation, together with an assessment of cognitive function. Plasma drug concentration was measured using high‐performance liquid chromatography (HPLC), and cholinesterase in red blood cells was measured using Ellman methods. Cognitive function was evaluated using the Mini‐Mental Scale Examination (MMSE). Plasma concentration of donepezil during ginkgo supplementation (mean ± SD [95% confidence interval]; 24.4 ± 12.6 ng/mL [17.1–31.7 ng/mL]) was not significantly different from that before ginkgo supplementation (22.7 ± 10.3 ng/mL [16.8–28.7 ng/mL]) or that 4 weeks after its discontinuation (25.0 ± 12.9 ng/mL [17.6–32.4 ng/mL]). There was no significant difference between cholinesterase in red blood cells before ginkgo supplementation (1.75 ± 0.21 U [1.63–1.87 U]), during ginkgo supplementation (1.91 ± 0.27 U [1.76–2.07 U]), and 4 weeks after its discontinuation (1.83 ± 0.29 U [1.66–2.00 U]). Ginkgo supplementation did not alter MMSE scores throughout the study. The present study shows that ginkgo supplementation does not have major impact on the pharmacokinetics and pharmacodynamics of donepezil.

Effect of adjunctive treatment with aripiprazole to atypical antipsychotics on cognitive function in schizophrenia patients

Second-generation antipsychotics yield only a modest improvement in cognitive benefit compared to first-generation antipsychotics. Aripiprazole, which is a partial dopamine D2 receptor agonist, may have an impact on cognitive dysfunction in patients with schizophrenia. This study administered aripiprazole or placebo to 36 outpatients with schizophrenia also receiving risperidone or olanzapine for 12 weeks in a double-blind, randomized, placebo-controlled study. Cognitive function was evaluated using the Brief Assessment of Cognition in Schizophrenia (BACS) just prior to drug administration as well as 12 weeks after. The PANSS and UKU side effect rating scales were used to evaluate the clinical response to additional treatment with aripiprazole. In a primary analyses, ANCOVA showed that there was an interaction between the treatment group and time for verbal fluency (p < 0.05), but not for any domain in BACS, PANSS or UKU side effect rating scales. Upon secondary analysis, however, the ameliorative change in motor speed as assessed by the BACS (p < 0.05) for those receiving aripiprazole was greater than that for the placebo group, whereas deterioration in verbal fluency (p < 0.01) and executive function (p < 0.01) in those receiving aripiprazole was significantly greater than in the placebo group. These results suggest that adjunctive treatment with aripiprazole improves motor speed but worsens some cognitive functions. It is likely that these effects are due to the dopamine D2 antagonistic effect of aripiprazole.

Association between cytochrome P450 (CYP) 2C19 polymorphisms and harm avoidance in Japanese

Polymorphic enzyme cytochrome P450 (CYP) 2C19 is expressed not only in the liver but also in the brain and mediates the biotransformation of 5‐hydroxytriptamine (5‐HT). We investigated possible association between genetic polymorphism of CYP2C19 and individual personality traits, possibly influenced by neurotransmitters. Mentally and physically healthy Japanese subjects were enrolled in this study (n = 352). Temperament and Character Inventory (TCI) and CYP2C19 genotyping were performed in all subjects. We detected CYP2C19*2 and *3 (http://www.imm.ki.se/CYPalleles/) using Amplichip CYP450 DNA tip. The number of genotypes classified as homozygous extensive metabolizer (EM), heterozygous EM, and poor metabolizer were 113, 181, and 58, respectively. Significant difference was found in TCI score in harm avoidance (HA; F = 3.138, P < 0.05). Post hoc analysis showed that TCI score in harm avoidance in homozygous EM was significantly lower than that in heterozygous EM (P < 0.05) or PM (P < 0.05). In sub‐item analyses, HA3 (shyness with strangers, P < 0.01) and HA1 (anticipatory worry, P < 0.05) of TCI scores were significantly different among CYP2C19 genotypes. Meanwhile, there were no differences in TCI scores of novelty seeking (NS; F = 0.350, n.s.), reward dependence (RD; F = 1.080, n.s.), or persistence (P; F = 0.786, n.s.) among CYP2C19 genotypes. This study demonstrated that a significant association between CYP2C19 activity and HA is present in Japanese.

Differential Effects of the Catechol-O-Methyltransferase Val158Met Genotype on the Cognitive Function of Schizophrenia Patients and Healthy Japanese Individuals

Background The functional polymorphism Val158Met in the catechol-O-methyltransferase (COMT) gene has been associated with differences in prefrontal cognitive functions in patients with schizophrenia and healthy individuals. Several studies have indicated that the Met allele is associated with better performance on measures of cognitive function. We investigated whether the COMT Val158Met genotype was associated with cognitive function in 149 healthy controls and 118 patients with schizophrenia. Methods Cognitive function, including verbal memory, working memory, motor speed, attention, executive function and verbal fluency, was assessed by the Brief Assessment of Cognition in Schizophrenia (BACS-J). We employed a one-way analysis of variance (ANOVA) and a multiple regression analysis to determine the associations between the COMT Val158Met genotype and the BACS-J measurements. Results The one-way ANOVA revealed a significant difference in the scores on the Tower of London, a measure of executive function, between the different Val158Met genotypes in the healthy controls (p = 0.023), and a post-hoc analysis showed significant differences between the scores on the Tower of London in the val/val genotype group (18.6 ± 2.4) compared to the other two groups (17.6 ± 2.7 for val/met and 17.1 ± 3.2 for met/met; p = 0.027 and p = 0.024, respectively). Multiple regression analyses revealed that executive function was significantly correlated with the Val158Met genotype (p = 0.003). However, no evidence was found for an effect of the COMT on any cognitive domains of the BACS-J in the patients with schizophrenia. Conclusion These data support the hypothesis that the COMT Val158Met genotype maintains an optimal level of dopamine activity. Further studies should be performed that include a larger sample size and include patients on and off medication, as these patients would help to confirm our findings.

No association between dietary patterns and depressive symptoms among a community-dwelling population in Japan

BackgroundStudies of the associations between diet and depression have primarily focused on single nutrients or foods. Recently, dietary patterns representing a combination of foods have attracted more interest than individual nutrient. The objective of this study was to examine the association between dietary patterns and depressive symptoms among a community-dwelling population in Japan.MethodsWe examined the association between dietary patterns and the risk of depression among 791 Japanese community-dwelling individuals. Diet was assessed with a validated brief-type self-administered diet history questionnaire (BDHQ). Dietary patterns from 52 predefined food groups [energy-adjusted food (g/d)] were extracted by principal component analysis. The Center for Epidemiologic Studies Depression Scale (CES-D) with a cut-off point of 16 was used to assess the prevalence of depression.ResultsA total of 97 subjects (12.3%) were classified as having depression. Four dietary patterns were identified: “Healthy”, “Western”, “Bread and confectionery”, and “Alcohol and accompanying” dietary patterns. After adjusting for potential confounders, the dietary patterns were not related to the risk of depression.ConclusionsThe present study failed to find associations between dietary patterns and the risk of depression. However, the interpretation of our results was hampered by the lack of certain data, including employment physical activity and longitudinal observations. Potential associations between dietary patterns and depressive symptoms were not completely ruled out. Future research exploring dietary patterns and depressive symptoms is warranted.

Comparison of ankle-brachial pressure index and pulse wave velocity as markers of cognitive function in a community-dwelling population

BackgroundVascular factors have been implicated in the development of cognitive decline and dementia. The purpose of this study is to determine the association of the Ankle Brachial pressure Index (ABI) and brachial-ankle Pulse Wave Velocity (ba-PWV) to cognitive impairment in a community-dwelling population.MethodsThe ABI and ba-PWV were measured using the volume-plethymographic apparatus in 388 subjects aged 60 years old and over. The Mini-Mental State Examination was also employed to measure global cognitive status. The effectiveness of the ABI and ba-PWV as putative markers of cognitive impairment were determined by using a multiple logistic regression analysis after adjusting for confounding factors.ResultsSubjects with poor cognition were significantly older and less well educated than those with normal cognition. According to the multiple logistic regression analysis, the lowest ABI tertile was found to be a significant independent risk factor (OR = 3.19, 95% CI = 1.30 to 7.82) of the cognitive impairment, whereas the highest brachial-ankle PWV tertile was not.ConclusionsA low ABI was an independent risk factor for cognitive impairment in community-dwelling older populations, whereas a high ba-PWV may not be. Further research will be required to analyze ABI and PWV with greater accuracy.

Inverse correlation between clinical response to paroxetine and plasma drug concentration in patients with major depressive disorders

There are few data concerning a clear relationship between the clinical effect of paroxetine and plasma drug concentrations, although therapeutic ranges have been established for some tricyclic antidepressants.

Minor genetic variants of the dopamine D4 receptor (DRD4) polymorphism are associated with novelty seeking in healthy Japanese subjects

Although an association between the dopamine receptor D4 (DRD4) gene and personality traits had been previously investigated, results from previous studies were not conclusive. This may be due to the method of grouping used, which categorized the gene population into two groups based on the length of the variable number of tandem repeats (VNTR) in exon 3. In the present study, we categorized 616 healthy Japanese subjects into more than two groups by further subdividing the DRD4 48-bp VNTR polymorphism, and compared Temperament and Character Inventory (TCI) scores among the groups. A significant difference was found between the DRD4 48-bp VNTR polymorphism and novelty seeking (p=0.016). The novelty-seeking scores in the subjects carrying the 5/5 genotype were significantly higher than in those carrying the 2/2 genotype (p=0.002) or the 4/4 genotype (p=0.005). However, when the conventional method of grouping was used (i.e., short alleles vs. long alleles), there were no significant associations between the DRD4 VNTR polymorphism and any TCI scores. Our results suggest that minor 5-repeat allele is associated with high novelty-seeking scores in healthy Japanese subjects.

Sex-specific effects of subjective memory complaints with respect to cognitive impairment or depressive symptoms

The aim of this study was to investigate the association between subjective memory complaints (SMC) and sex.