In vivo functional neurochemistry of human cortical cholinergic function during visuospatial attention

Cortical acetylcholine is involved in key cognitive processes such as visuospatial attention. Dysfunction in the cholinergic system has been described in a number of neuropsychiatric disorders. Levels of brain acetylcholine can be pharmacologically manipulated, but it is not possible to directly measure it in vivo in humans. However, key parts of its biochemical cascade in neural tissue, such as choline, can be measured using magnetic resonance spectroscopy (MRS). There is evidence that levels of choline may be an indirect but proportional measure of acetylcholine availability in brain tissue. In this study, we measured relative choline levels in the parietal cortex using functional (event-related) MRS (fMRS) during performance of a visuospatial attention task, with a modelling approach verified using simulated data. We describe a task-driven interaction effect on choline concentration, specifically driven by contralateral attention shifts. Our results suggest that choline MRS has the potential to serve as a proxy of brain acetylcholine function in humans

Association between butyrylcholinesterase K variant and mild cognitive impairment in the Thai community-dwelling patients

Natsalil Pongthanaracht,1 Somchai Yanarojana,1 Darawan Pinthong,1 Supeenun Unchern,1 Amnuay Thithapandha,1 Prasert Assantachai,2 Porntip Supavilai11Department of Pharmacology, Faculty of Science, 2Department of Preventive and Social Medicine, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, ThailandObjective: To study the association of the butyrylcholinesterase K variant (BChE-K) and the plasma BChE activity with mild cognitive impairment (MCI) in Thai community-dwelling patients.Methods: One hundred patients diagnosed with MCI and 100 control subjects were recruited from the community-dwelling setting in Bangkok, Thailand. The genotype and allele distributions of the BChE-K were determined by polymerase chain reaction and subsequent DNA sequencing. The BChE activity was measured in plasma according to the Ellman’s method.Results: The BChE-K allele frequencies in the Thai community-dwelling patients were in accordance with other ethnics. The BChE-K allele frequency in the control subjects (12%) was higher than that of MCI patients (5.5%), suggesting a protective role of BChE-K for MCI in the Thai community-dwelling patients. The BChE-K homozygotes were significantly associated with lower BChE activity.Conclusion: Our results suggested that the BChE-K may be implicated as a protective factor for MCI in the Thai community-dwelling patients, although a further study with a large sample size is warranted to confirm this.Keywords: butyrylcholinesterase K variant, butyrylcholinesterase activity, mild cognitive impairment, Thai community-dwelling patient

Association of CYP3A4/5, ABCB1 and ABCC2 polymorphisms and clinical outcomes of Thai breast cancer patients treated with tamoxifen

Insee Sensorn,1 Ekaphop Sirachainan,2 Montri Chamnanphon,3 Ekawat Pasomsub,4 Narumol Trachu,5 Porntip Supavilai,1 Chonlaphat Sukasem,3 Darawan Pinthong11Department of Pharmacology, Faculty of Science, Mahidol University, Bangkok, Thailand; 2Division of Medical Oncology, Department of Medicine, 3Division for Pharmacogenomics and Personalized Medicine, 4Division for Virology, Department of Pathology, 5Research Center, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, ThailandBackground: Pharmacogenetic study of cytochrome P450 (CYP) gene CYP2D6 and tamoxifen outcomes remain controversial. Apart from CYP2D6, other drug-metabolizing enzymes and transporters also play a role in tamoxifen metabolic pathways. The aim of this study is to investigate the impact of CYP3A4/5, ABCB1, and ABCC2 polymorphisms on the risk of recurrence in Thai patients who received tamoxifen adjuvant therapy.Methods: Patients with early-stage breast cancer who received tamoxifen adjuvant therapy were recruited in this study. All six single-nucleotide polymorphisms (SNPs), including CYP3A4*1B (-392 A>G)/*18(878 T>C), CYP3A5*3(6986 G>A), ABCB1 3435 C>T, ABCC2*1C (-24 C>T), and ABCC2 68231 A>G, were genotyped using real-time polymerase chain reaction assays. The impacts of genetic variants on disease-free survival (DFS) were analyzed using the Kaplan–Meier method and Cox regression analysis.Results: The ABCB1 3435 C>T was found to have the highest allele frequency among other variants; however, CYP3A4*1B/*18 could not be found in this study. Patients with heterozygous ABCB1 3435 CT genotype showed significantly shorter DFS than those with homozygous 3435 CC genotype (P = 0.041). In contrast, patients who carried homozygous 3435 TT genotype showed no difference in DFS from wild-type 3435 CC patients. Cox regression analysis showed that the relative risk of recurrence was increased by five times (P = 0.043; hazard ratio = 5.11; 95% confidence interval: 1.05–24.74) in those patients carrying ABCB1 3435 CT genotype compared to those with ABCB1 3435 CC.Conclusion: ABCB1 3435 C>T is likely to have a clinically significant impact on recurrence risk in Thai patients with breast cancer who receive tamoxifen adjuvant therapy.Keywords: breast cancer, CYP3A4/5, drug transporters, pharmacogenetics, disease-free survival, tamoxife

ABCB1 and ABCC2 and the risk of distant metastasis in Thai breast cancer patients treated with tamoxifen

Insee Sensorn,1,* Chonlaphat Sukasem,2,* Ekaphop Sirachainan,3 Montri Chamnanphon,2 Ekawat Pasomsub,4 Narumol Trachu,5 Porntip Supavilai,1 Darawan Pinthong,1 Sansanee Wongwaisayawan6 1Department of Pharmacology, Faculty of Science, Mahidol University, 2Division of Pharmacogenomics and Personalized Medicine, Department of Pathology, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, 3Division of Medical Oncology, Department of Medicine, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, 4Division of Virology, Department of Pathology, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, 5Research Center, Faculty of Medicine, Ramathibodi Hospital, 6Division of Anatomical Pathology, Department of Pathology, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand *These authors contributed equally to this work Background: Genetic polymorphisms of drug-metabolizing enzymes and transporters have been extensively studied with regard to tamoxifen treatment outcomes. However, the results are inconclusive. Analysis of organ-specific metastasis may reveal the association of these pharmacogenetic factors. The aim of this study is to investigate the impact of CYP3A5, CYP2D6, ABCB1, and ABCC2 polymorphisms on the risk of all distant and organ-specific metastases in Thai patients who received tamoxifen adjuvant therapy. Methods: Genomic DNA was extracted from blood samples of 73 patients with breast cancer who received tamoxifen adjuvant therapy. CYP3A5 (6986A>G), CYP2D6 (100C>T), ABCB1 (3435C>T), and ABCC2 (-24C>T) were genotyped using allelic discrimination real-time polymerase chain reaction assays. The impacts of prognostic clinical factors and genetic variants on disease-free survival were analyzed using the Kaplan–Meier method and Cox regression analysis. Results: In the univariate analysis, primary tumor size >5 cm was significantly associated with increased risk of distant metastasis (P=0.004; hazard ratio [HR] =3.05; 95% confidence interval [CI], 1.44–6.47). In the multivariate analysis, tumor size >5 cm remained predictive of distant metastasis (P<0.001; HR=5.49; 95% CI, 2.30–13.10). ABCC2 -24CC were shown to be associated with increased risk of distant metastasis (P=0.040; adjusted HR=2.34; 95% CI, 1.04–5.27). The combined genotype of ABCC2 -24CC – ABCB1 3435 CT+TT was associated with increased risk of distant and bone metastasis (P=0.020; adjusted HR=2.46; 95% CI, 1.15–5.26 and P=0.040; adjusted HR=3.70; 95% CI, 1.06–12.89, respectively). Conclusion: This study indicates that polymorphisms of ABCC2 and ABCB1 are independently associated with bone metastasis. Further prospective studies with larger sample sizes are needed to verify this finding. Keywords: breast cancer, tamoxifen, ABCB1, ABCC2, pharmacogenetics, distant metastasi

Clinically relevant genetic variants of drug-metabolizing enzyme and transporter genes detected in Thai children and adolescents with autism spectrum disorder

Sadeep Medhasi,1–3 Ekawat Pasomsub,4 Natchaya Vanwong,1,2 Nattawat Ngamsamut,5 Apichaya Puangpetch,1,2 Montri Chamnanphon,1,2 Yaowaluck Hongkaew,1,2 Penkhae Limsila,5 Darawan Pinthong,3 Chonlaphat Sukasem1,2 1Division of Pharmacogenomics and Personalized Medicine, Department of Pathology, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok, Thailand; 2Laboratory for Pharmacogenomics, Somdech Phra Debaratana Medical Center, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok, Thailand; 3Department of Pharmacology, Faculty of Science, Mahidol University, Bangkok, Thailand; 4Division of Virology, Department of Pathology, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok, Thailand; 5Yuwaprasart Waithayopathum Child and Adolescent Psychiatric Hospital, Department of Mental Health Services, Ministry of Public Health, Samut Prakarn, Thailand Abstract: Single-nucleotide polymorphisms (SNPs) among drug-metabolizing enzymes and transporters (DMETs) influence the pharmacokinetic profile of drugs and exhibit intra- and interethnic variations in drug response in terms of efficacy and safety profile. The main objective of this study was to assess the frequency of allelic variants of drug absorption, distribution, metabolism, and elimination-related genes in Thai children and adolescents with autism spectrum disorder. Blood samples were drawn from 119 patients, and DNA was extracted. Genotyping was performed using the DMET Plus microarray platform. The allele frequencies of the DMET markers were generated using the DMET Console software. Thereafter, the genetic variations of significant DMET genes were assessed. The frequencies of SNPs across the genes coding for DMETs were determined. After filtering the SNPs, 489 of the 1,931 SNPs passed quality control. Many clinically relevant SNPs, including CYP2C19*2, CYP2D6*10, CYP3A5*3, and SLCO1B1*5, were found to have frequencies similar to those in the Chinese population. These data are important for further research to investigate the interpatient variability in pharmacokinetics and pharmacodynamics of drugs in clinical practice. Keywords: Thai population, ADME, pharmacokinetics, autism spectrum disorder, microarray, pharmacogenetic

The relationship between the adrenoceptor and nonadrenoceptor-mediated effects of imidazoline- and imidazole-containing compounds

No abstract available

Water-soluble macromers based on 2-acrylamido-2-methyl-1-propanesulfonic acid sodium salt (Na-AMPS) for rapid in situ hydrogel film formation

The in situ formation of hydrogels has potential for a number of biomedical applications but their generation via conventional polymerization techniques has a number of limitations, such as toxicity and reaction time. The use of macromers in hydrogel formulations can help overcome these limitations. In this work, we synthesized a new functionalized macromer formed via the copolymerization of 2-acrylamido-2-methylpropane sulfonic acid sodium salt (AMPS) and acid-functional monomers that can undergo a ring-opening reaction with allyl glycidyl ether (AGE) to generate the desired pendant vinyl macromer functionality. These macromers were characterized by 1H nuclear magnetic resonance (NMR) spectroscopy, Fourier transform infrared (FT-IR) spectroscopy and gel permeation chromatography (GPC) to provide evidence for successful macromer synthesis and subsequent polymerization. Using a UV-initiated crosslinking approach with poly(ethylene glycol) diacrylate (PEGDA), the hydrogels were fabricated from the macromer solution, with the gelation time being reduced from 1200 s to 10 s when compared to hydrogel formation from regular vinyl monomers. While different acidic monomers result in distinct tensile properties, hydrogels containing 2-carboxyethyl acrylate (CEA) exhibit low strength but high elongation. In contrast, those with methacrylic acid (MAA) demonstrate higher strength and lower elongation. Therefore, using a balanced combination of each is a logical approach for achieving a robust final hydrogel film. In summary, we have produced a new macromer possessing characteristics highly conducive to rapid hydrogel synthesis. This macromer approach holds potential for use in in situ hydrogel formation, where a viscous solution can be applied to the target area and subsequently hardened to its hydrogel. We envisage its application primarily in the biomedical field