Distribution patterns of molecular markers of antimalarial drug resistance in Plasmodium falciparum isolates on the Thai-Myanmar border during the periods of 1993-1998 and 2002-2008.

BACKGROUND: Polymorphisms of Plasmodium falciparum chloroquine resistance transporter (pfcrt), Plasmodium falciparum multi-drug resistance 1 (pfmdr1) and Plasmodium falciparum kelch 13-propeller (pfk13) genes are accepted as valid molecular markers of quinoline antimalarials and artemisinins. This study investigated the distribution patterns of these genes in P. falciparum isolates from the areas along the Thai-Myanmar border during the two different periods of antimalarial usage in Thailand. RESULTS: Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) were used to detect pfcrt mutations at codons 76, 220, 271, 326, 356, and 371 as well as pfmdr1 mutation at codon 86. The prevalence of pfcrt mutations was markedly high (96.4-99.7%) in samples collected during both periods. The proportions of mutant genotypes (number of mutant/total isolate) at codons 76, 220, 271, 326, 356 and 371 in the isolates collected during 1993-1998 (period 1) compared with 2002-2008 (period 2) were 97.9% (137/140) vs. 97.1% (401/413), 97.9% (140/143) vs. 98.8% (171/173), 97.2% (139/143) vs. 97.1% (333/343), 98.6% (140/142) vs. 99.7% (385/386), 96.4% (134/139) vs. 98.2% (378/385) and 97.8% (136/139) vs. 98.9% (375/379), respectively. Most isolates carried pfmdr1 wild-type at codon 86, with a significant difference in proportions genotypes (number of wild type/total sample) in samples collected during period 1 [92.9% (130/140)] compared with period 2 [96.9% (379/391)]. Investigation of pfmdr1 copy number was performed by real-time PCR. The proportions of isolates carried 1, 2, 3 and 4 or more than 4 copies of pfmdr1 (number of isolates carried correspondent copy number/total isolate) were significantly different between the two sample collecting periods (65.7% (90/137) vs. 87.8% (390/444), 18.2% (25/137) vs. 6.3%(28/444), 5.1% (7/137) vs. 1.4% (6/444) and 11.0% (15/137) vs. 4.5% (20/444), for period 1 vs. period 2, respectively). No pfk13 mutation was detected by nested PCR and nucleotide sequencing in all samples with successful analysis (n = 68). CONCLUSIONS: The persistence of pfcrt mutations and pfmdr1 wild-types at codon 86, along with gene amplification in P. falciparum, contributes to the continued resistance of chloroquine and mefloquine in P. falciparum isolates in the study area. Regular surveillance of antimalarial drug resistance in P. falciparum, incorporating relevant molecular markers and treatment efficacy assessments, should be conducted.

Exploring genetic polymorphisms among Plasmodium vivax isolates from the Thai-Myanmar borders using circumsporozoite protein (pvcsp) and ookinete surface protein (pvs25) encoding genes.

Plasmodium vivax malaria cases remain high along the Thai-Myanmar and Thai-Cambodia borders. Plasmodium vivax circumsporozoite protein (pvcsp) and Plasmodium vivax ookinete surface protein (pvs25) genes are promising molecular markers of the genetic diversity of P. vivax. This study investigated the genetic diversity of pvcsp and pvs25 in P. vivax isolates collected from the Thai-Myanmar border. The DNA samples were amplified, and the genotypes were analyzed by PCR-RFLP and DNA sequencing. Pvcsp genotypes, VK210, VK247, and mixed types, were found in 203 (91.9%), 15 (6.8%), and 3 (1.3%) of the isolates, respectively. Twenty-four allelic variants were observed, of which a high prevalence of VK210E and VK247E were reported. Two pvcsp variants, VK210C and VK210M showed significantly higher parasite density (46,234 (1154-144,000) vs. 25,606 (1373-68,878), respectively). The genetic diversity of pvcsp along the Thai-Myanmar border during 2002-2015 showed dynamic changes with both positive and negative selection. The frequency and distribution of pvcsp pattern might be changed over time and might be other factors contributing to gene selection. Three amino acid substitutions of pvs25, i.e., E97Q, I130T, and Q131K, were investigated with frequencies of 10 (4.5%), 221 (100%), and 204 (92.3%) isolates, respectively. There was no association between parasite density and pvs25 polymorphisms. The frequency of pvs25 polymorphism was similar to that previously reported, with the absence of random mutation. In conclusion, the genetic variation of pvcsp was changed over times whereas the genetic diversity of pvs25 was limited; these variations would be helpful for further vaccine development against P. vivax malaria.

The Role of Herbal Medicine in Cholangiocarcinoma Control: A Systematic Review.

The growing incidence of cholangiocarcinoma (bile duct cancer) and limited treatment options stimulate a pressing demand for research and the development of new chemotherapeutics against cholangiocarcinoma. This study aimed to systematically review herbs and herb-derived compounds or herbal formulations that have been investigated for their anti-cholangiocarcinoma potential. Systematic literature searches were conducted in three electronic databases: PubMed, ScienceDirect, and Scopus. One hundred and twenty-three research articles fulfilled the eligibility critera and were included in the analysis (68 herbs, isolated compounds and/or synthetic analogs, 9 herbal formulations, and 119 compounds that are commonly found in several plant species). The most investigated herbs were Atractylodes lancea (Thunb.) DC. (Compositae) and Curcuma longa L. (Zingiberaceae). Only A. lancea (Thunb.) DC. (Compositae) has undergone the full process of nonclinical and clinical development to deliver the final product for clinical use. The extracts of A. lancea (Thunb.) DC. (Compositae), Garcinia hanburyi Hook.f. (Clusiaceae), and Piper nigrum L. (Piperaceae) exhibit antiproliferative activities against human cholangiocarcinoma cells (IC50 < 15 µg/mL). Cucurbitacin B and triptolide are herbal isolated compounds that exhibit the most promising activities (IC50 < 1 µM). A series of experimental studies (in vitro, in vivo, and humans) confirmed the anti-cholangiocarcinoma potential and safety profile of A. lancea (Thunb.) DC. (Compositae) and its active compounds atractylodin and ß-eudesmol, including the capsule pharmaceutical of the standardized A. lancea (Thunb.) DC. (Compositae) extract. Future research should be focused on the full development of the candidate herbs to deliver products that are safe and effective for cholangiocarcinoma control.

Current prevalence and geographic distribution of helminth infections in the parasitic endemic areas of rural Northeastern Thailand.

BACKGROUND: Helminth infection is a global health issue that not only causes acute helminthiasis but long-term infection may lead to complicated symptoms as well as severe complications. The World Health Organization cooperated with the Ministry of Public Health in many countries, particularly where high prevalence, spending a lot of resources for limiting the infection. In Thailand, the incidence of parasitic helminth infections was continuously declined in the last few decades according to several campaigns for parasitic elimination. However, the rural community in the northeast of Thailand where the highest prevalence of the country still needs to be monitored. This present study aims to report the current prevalence of parasitic helminth infections in Nakhon Ratchasima and Chaiyaphum provinces where sharing a huge area of the northeastern region of Thailand but only a few studies have been published. METHODS: The stool specimens were collected from 11,196 volunteers and processed by modified Kato-Katz thick smear, PBS-ethyl acetate concentration techniques, and PCR. The epidemiological data were collected, analyzed, and used for generating of parasitic hotspots. RESULTS: The results indicated that O. viverrini remains the major parasite in this area with a total prevalence of 5.05% followed by Taenia spp., Hookworms, T. trichiura, and Echinostoma spp., respectively. Mueang district of Chaiyaphum province has the highest prevalence especially O. viverrini with a prevalence of 7.15% that higher than the latest national surveillance. Interestingly, the prevalence of O. viverrini was hugely reported (more than 10%) in five subdistricts. The geographic localization of O. viverrini infections revealed that a lot of water reservoirs such as the lakes or branches of the river in the two-most prevalent subdistricts. Our finding indicated that gender and age were insignificantly different. CONCLUSION: This finding suggested that the parasitic helminth infection in the rural areas of northeast of Thailand remains high and the housing location is a major contributing factor for the parasitic infection.

Host susceptibility genes of asymptomatic malaria from South Central Timor, Eastern Indonesia.

Host genetic factors, such as the genes for various cytokines and adhesion molecules, play a significant role in determining susceptibility to malaria infection. Polymorphisms in host genes have been correlated with malaria infection in both African and Asian regions. The purpose of this study was to investigate the association between both cytokine and adhesion molecule genotypes with susceptibility to malaria infection in humans. Ten cytokine polymorphism loci (IL4 + 33, IL4-590, IL6-174, IL10-1082, IL10-1035, IL12p40, TNF-238, TNF-308, TNF-1031, and TNF-ß) and three adhesion molecule polymorphism loci (CD36 exon 10, ICAM-1 Kilifi, and ICAM-1 exon 6) were genotyped using PCR-RFLP analysis. We conducted this study on 178 asymptomatic malaria subjects and 122 uninfected subjects. Results showed that certain CD36 exon 10 and IL10-3575 polymorphisms were associated with asymptomatic infection. The heterozygous (GT) and homozygous (GG) genotypes for CD36 exon 10 are associated with an increased risk of malaria infection. On the other hand, the homozygous genotype (AA) for IL10-3575 reduced the risk of asymptomatic malaria infection. No significant differences were found for the other polymorphisms studied. We also found that a polymorphism in CD36 exon 10 was strongly associated with asymptomatic malaria caused specifically by Plasmodium vivax. These findings suggest that the G allele of CD36 exon 10 is associated with an increased risk of asymptomatic malaria infection. On the other hand, the genotype AA for IL10-3575 was associated with a reduced risk of malaria infection.

Modulatory Effects of Atractylodin and ß-Eudesmol on Human Cytochrome P450 Enzymes: Potential Drug-Drug Interactions.

Atractylodin and ß-eudesmol, the major bioactive compounds in Atractylodes lancea, are promising candidates for anti-cholangiocarcinoma. The inhibitory effects of both compounds on human rCYP1A2, rCYP2C9, rCYP2C19, rCYP2D6 and rCYP3A4 enzymes were investigated using luminogenic CYP450 kits. The modulatory effects were investigated in mouse livers following a daily oral dose of atractylodin or ß-eudesmol at 100 mg/kg body weight for 1, 7, 14, and 21 days. The inhibitory effects of both compounds on all rCYP450s were weak (IC50: 167 to >686 µM). ß-Eudesmol showed the most potent inhibitory effect on rCYP2C19 (IC50 = 172.7 µM) and rCYP3A4 (IC50 = 218.6 µM). Results of the ex vivo study showed that short exposure (1-7 days) of atractylodin and ß-eudesmol resulted in the upregulation of mRNA. Prolonged exposure to the daily oral dose for at least 14 days significantly downregulated the expressions of mRNA and proteins, which correlated with the decrease in the activities of mCYP1A2 and mCYP3A11. Based on the results of the ex vivo study, clinical uses of atractylodin or ß-eudesmol for the treatment of cholangiocarcinoma are of concern for the risk of toxicity due to hCYP3A4 inhibition following chronic dosing, as well as the metabolic interaction with the coadministered drugs that are metabolized by hCYP3A4.

Clinical pharmacokinetics of quinine and its relationship with treatment outcomes in children, pregnant women, and elderly patients, with uncomplicated and complicated malaria: a systematic review.

BACKGROUND: Standard dosage regimens of quinine formulated for adult patients with uncomplicated and complicated malaria have been applied for clinical uses in children, pregnant women, and elderly. Since these populations have anatomical and physiological differences from adults, dosage regimens formulated for adults may not be appropriate. The study aimed to (i) review existing information on the pharmacokinetics of quinine in children, pregnant women, and elderly populations, (ii) identify factors that influence quinine pharmacokinetics, and (iii) analyse the relationship between the pharmacokinetics and treatment outcomes (therapeutic and safety) of various dosage regimens of quinine. METHODS: Web of Sciences, Cochrane Library, Scopus, and PubMed were the databases applied in this systematic search for relevant research articles published up to October 2020 using the predefined search terms. The retrieved articles were initially screened by titles and abstracts to exclude any irrelevant articles and were further evaluated based on full-texts, applying the predefined eligibility criteria. Excel spreadsheet (Microsoft, WA, USA) was used for data collection and management. Qualitative data are presented as numbers and percentages, and where appropriate, mean + SD or median (range) or range values. RESULTS: Twenty-eight articles fulfilled the eligibility criteria, 19 in children, 7 in pregnant women, and 2 in elderly (14 and 7 articles in complicated and uncomplicated malaria, respectively). Severity of infection, routes of administration, and nutritional status were shown to be the key factors impacting quinine pharmacokinetics in these vulnerable groups. CONCLUSIONS: The recommended dosages for both uncomplicated and complicated malaria are, in general, adequate for elderly and children with uncomplicated malaria. Dose adjustment may be required in pregnant women with both uncomplicated and complicated malaria, and in children with complicated malaria. Pharmacokinetics studies relevant to clinical efficacy in these vulnerable groups of patients with large sample size and reassessment of MIC (minimum inhibitory concentration) should be considered.

Spectroscopic observations of ß-eudesmol binding to human cytochrome P450 isoforms 3A4 and 1A2, but not to isoforms 2C9, 2C19, and 2D6.

ß-Eudesmol (BEU) is a sesquiterpenoid component of Atractylodes lancea with cytotoxic activity against cholangiocarcinoma. Its lipophilic nature makes BEU a likely substrate of human cytochrome P450 (P450) enzymes.Using ligand-binding difference spectroscopy, the affinities of this compound to recombinant CYP1A2, CYP2C9, CYP2C19, CYP2D6, and CYP3A4 were investigated in Escherichia coli membrane preparations.CYP3A4 showed a type I spectral change, with a binding constant Ks of 77 ± 23 (mean ± SD) µM at 0.5 µM P450 (Ks/[P450] ≈ 155). The reference substrate testosterone (TES) and the inhibitor fluconazole bound to the enzyme with apparent affinities of 86 ± 4 µM (type I) and 21 µM (type II), respectively. BEU was bound by CYP3A4 in a non-cooperative manner (Hill coefficient n ≈ 0.8). CYP1A2 showed reverse type I difference spectra with either BEU or caffeine (CAF). The CYP1A2 affinity for BEU was higher (0.23 mM) than for CAF (0.37 mM) but lower than for phenacetin (0.11 mM, type I). BEU did not bind significantly to CYP2C9, CYP2C19, and CYP2D6.Confirmation of metabolic activity and studies on the involvement of other human P450 isoforms are required. Double-beam spectrometry is needed to validate Ks measurements made with a microplate reader.

Enhanced oral bioavailability and biodistribution of atractylodin encapsulated in PLGA nanoparticle in cholangiocarcinoma.

Atractylodes lancea (Thunb) DC. and its bioactive compound atractylodin (ATD), have been shown to exert promising anticancer activity against cholangiocarcinoma (CCA) both in vitro and in vivo. However, the clinical development of ATD could be hindered due to hydrophobicity and poor pharmacokinetic properties, and thus, the requirement of high dose administration and the risk of toxicity. In the present study, ATD-loaded in PLGA nanoparticles (ATD-PLGA) and that coated with chitosan (ATD-PLGA-CS) were developed using nanoprecipitation and single emulsification methods, respectively. The optimized ATD-PLGA formulation provided superior physical and pharmaceutical properties over ATD-PLGA-CS. The antiproliferative activity of ATD-PLGA against the two CCA cell lines, HuCCT1 and CL6, and the normal cell line (OUMS-36T-1F) was evaluated using MTT assay. Results showed that normal epithelial cell was less sensitive to ATD-PLGA compared to both CCA cell lines. In mice, the radiolabelled 99m Tc-ATD-PLGA showed superior pharmacokinetic profile over free 99m Tc-ATD, as evidenced by a 2.7-fold increase of area under plasma concentration-time curve (AUC0-∞ ), maximum plasma concentration (Cmax ), time to Cmax (tmax ), and mean residence time (MRT). Higher accumulation of 99m Tc-ATD-PLGA was observed in vital organs/tissues such as blood, liver, heart, and kidney, compared with free 99m Tc-ATD-PLGA. Altogether, the results suggest that PLGA NPs could be a suitable drug delivery carrier for ATD in CCA.

Pretreatment gametocyte carriage in symptomatic patients with Plasmodium falciparum and Plasmodium vivax infections on the Thai-Myanmar border.

Background&objectives: Changes in parasite biology, particularly the gametocytogenesis process, could be one of the important contributing factors for worldwide malaria resurgence. The present study investigated the prevalence rates of pretreatment gametocyte carriage and density in Plasmodium falciparum and P. vivax infections in the low malaria-endemic area on the Thai-Myanmar border. METHODS: One hundred and twenty-six blood samples were collected from patients with signs and symptoms of malaria who attended malaria clinics. Malaria positive cases detected by microscopic examination were confirmed by species-specific nested-PCR in 97 (29 and 68 samples for P. falciparum and P. vivax, respectively). RESULTS: The proportion of P. vivax and P. falciparum-infected samples was 70.1: 29.9%. The density in P. falciparum positive samples [median (95%CI): 10,340 (5280-19,200) µ/l] was significantly higher than P. vivax positive samples [4508 (3240-6120) µ/l]. Sixteen out of twenty-nine (55.2%) and 36 out of 68 (52.9%) P. falciparum- and P. vivax-infected samples, respectively, were gametocyte-positive. Gametocyte density in the P. falciparum-infected[124 (69-253) /µl] was significantly higher than that of the P. vivax-infected [54 (45-70)/µl] samples. A significant correlation between gametocyte density and pretreatment parasitemia was only detected in P. falciparum-infected, but not P. vivax-infected samples. INTERPRETATION & CONCLUSION: The observed high prevalence rates of pretreatment gametocyte carriage of both malaria species, which serves as a large malaria reservoir, particularly in P. falciparum infection, could have a significant impact on malaria control in the endemic populations.

Preclinical Toxicology and Anticholangiocarcinoma Activity of Oral Formulation of Standardized Extract of Zingiber Officinale.

Cholangiocarcinoma (CCA) remains a significant public health problem in Thailand. New effective and safe drugs are urgently needed. Zingiber officinale Roscoe (ZO) is a widely used medicinal plant for the treatment of several ailments, and the animal study suggests a potential anti-CCA activity. The present study aimed to develop the oral formulation of standardized extract of ZO and investigate toxicological profiles (acute, repeated dose, and chronic toxicity), including anti-CCA activity of the ZO formulation. The oral pharmaceutical formulation of the standardized ZO extract was successfully developed with an acceptable level of contamination and physicochemical and pharmaceutical properties. Acute, subacute, and chronic toxicity tests were conducted in healthy Sprague Dawley rats according to the OECD guidelines. The results showed no evidence of toxicity and death in the acute and subacute toxicity testing with the maximum tolerated dose (MTD) of 5000 and 2000 mg/kg body weight, respectively. Chronic toxicity revealed MTD and No-Observed-Adverse-Effect level (NOAEL) of 1000 mg/kg body weight. The anti-CCA activity was evaluated in CCA-xenografted mouse model. The formulated ZO powder was fed to animals daily for 30 days. Significant anti-CCA activity on tumor growth inhibition and prolongation of survival time were demonstrated at the high (2000 mg/kg body weight) and moderate (1000 mg/kg body weight) dose levels. Further investigation to elucidate molecular targets of action of ZO against CCA cells is encouraged.

ß-Eudesmol induces the expression of apoptosis pathway proteins in cholangiocarcinoma cell lines.

BACKGROUND: Cholangiocarcinoma (CCA) is a neglected disease prevalent in developing countries with high burden and mortality rate, and there is no effective treatment. We aimed to investigate ß-eudesmol molecular target of action in human CCA cell lines using the selected key molecules of apoptotic pathways. MATERIALS AND METHODS: Two CCA cell lines (HuH28 and HuCCT1) were assessed at different time points after ß-eudesmol treatment for mRNA and protein expression profiles of caspase-3, -8, -9, p53, p21, Bcl-2, and Bax by real-time polymerase chain reaction and western blot, respectively. RESULTS: ß-eudesmol induced expressions of p21 and p53 in mRNA/protein level in HuH28 and HuCCT1 cells. These CCA cells also expressed caspase-3, -8, -9 and bax (mRNA and/or protein level) among others after ß-eudesmol treatment indicating its role in both intrinsic and extrinsic caspase-dependent apoptotic pathways. CONCLUSION: The study demonstrated that ß-eudesmol induced the expression of apoptosis pathway proteins, suggesting its potential role in promoting the caspase-dependent apoptotic pathway, and induction of the cell cycle arrest in CCA cell lines. ß-eudesmol can be considered as a potential compound for further investigation as an anti-CCA agent.

A Worldwide Map of Plasmodium falciparum K13-Propeller Polymorphisms.

BACKGROUND: Recent gains in reducing the global burden of malaria are threatened by the emergence of Plasmodium falciparum resistance to artemisinins. The discovery that mutations in portions of a P. falciparum gene encoding kelch (K13)-propeller domains are the major determinant of resistance has provided opportunities for monitoring such resistance on a global scale. METHODS: We analyzed the K13-propeller sequence polymorphism in 14,037 samples collected in 59 countries in which malaria is endemic. Most of the samples (84.5%) were obtained from patients who were treated at sentinel sites used for nationwide surveillance of antimalarial resistance. We evaluated the emergence and dissemination of mutations by haplotyping neighboring loci. RESULTS: We identified 108 nonsynonymous K13 mutations, which showed marked geographic disparity in their frequency and distribution. In Asia, 36.5% of the K13 mutations were distributed within two areas--one in Cambodia, Vietnam, and Laos and the other in western Thailand, Myanmar, and China--with no overlap. In Africa, we observed a broad array of rare nonsynonymous mutations that were not associated with delayed parasite clearance. The gene-edited Dd2 transgenic line with the A578S mutation, which expresses the most frequently observed African allele, was found to be susceptible to artemisinin in vitro on a ring-stage survival assay. CONCLUSIONS: No evidence of artemisinin resistance was found outside Southeast Asia and China, where resistance-associated K13 mutations were confined. The common African A578S allele was not associated with clinical or in vitro resistance to artemisinin, and many African mutations appear to be neutral. (Funded by Institut Pasteur Paris and others.).

CYP2C9, CYP2C19, CYP2D6 and CYP3A5 polymorphisms in South-East and East Asian populations: A systematic review.

WHAT IS KNOWN AND OBJECTIVE: Genetic polymorphism is one of the most important factors responsible for interindividual and interethnic variability in drug response. Studies in major populations, ie, Caucasians, Asians, and Africans, have provided evidence of differences in the genotype frequencies of major drug-metabolizing enzyme cytochrome P450 (CYP). This study aimed to review systematically, all relevant articles related to the genetic polymorphisms in CYP2C9, CYP2C19, CYP2D6 and CYP3A5 in South-East and East Asian (SEEA) populations. METHODS: Articles that report genetic polymorphisms, genotype frequencies and allele frequencies in CYP2C9, CYP2C19, CYP2D6 and CYP3A5 were retrieved from the PubMed database. RESULTS AND DISCUSSIONS: A total of 86 studies that fulfilled the eligibility criteria representing different ethnic populations of SEEA, ie, Burmese, Chinese, Japanese, Karen ethnic minority, Korean, Malaysian, Philippino, Singaporean, Taiwanese, Thai, Indonesian, and Vietnamese, were included in the analysis. In general, the genotype frequencies across SEEA populations are comparable. The CYP2C9*1/*1 (69.3%-99.1%), *1/*3 (2.3%-20.1%) and *3/*3 (0%-2.2%) genotypes are reported in most SEEA populations. Six major CYP2C19 genotypes, ie, *1/*1 (6.25%-88.07%), *1/*2 (21.5%-86.46%), *1/*3 (0.8%-15.8%), *2/*2 (3.4%-14.5%), *2/*3 (0%-7.3%) and *3/*3 (0%-10.2%), are reported in most SEEA populations. Major CYP2D6 genotypes include *10/*10 (0%-69.6%), *1/*1 (0%-61.21%) and *1/*10 (0%-62.0%). Major CYP3A5 genotypes are *3/*3 (2.0%-71.4%), *1/*3 (16.0%-57.1%) and *1/*1 (0%-82.0%). Genotyping of abnormal genotypes of CYP2C9 (*1/*3), CYP2C19 (*1/*2, *1/*3), CYP3A5 (*1/*3) and CYP2D6 (*5/*10) associated with IM (Intermediate metabolizer) status, may be clinically beneficial in SEEA populations. Similarly, with CYP2C19 (*2/*2, *2/*3), CYP2D6 (*5/*5 ) linked to PM (Poor metabolizer), CYP2D6 (*10/*10, *1/*5 and to lesser extent *1/*4, *2/*5, *10/*41, *10/*49, *10/*14) and CYP3A5 (*1/*1) associated with EM (extensive metabolizer). WHAT IS NEW AND CONCLUSION: Sufficient number of studies has provided comparable results in general. This review suggests that comparable genotype frequencies of CYP2C9, CYP2C19, CYP2D6 and CYP3A5 exist among the SEEA populations. It is noted that more research data are reported from East Asians compared with South-East Asians. Concerned efforts are required to establish partnerships among SEEA countries that will ensure sufficient data from South-East Asian countries which will assist in establishing the databases for SEEA populations.

Anti-inflammatory effect of naringin and sericin combination on human peripheral blood mononuclear cells (hPBMCs) from patient with psoriasis.

BACKGROUND: Several immunological pathways, particularly skin inflammation via various pro-inflammatory cytokines have been reported to be involved in the pathogenesis and clinical manifestations of psoriasis. The aim of the study was to investigate the potential role of naringin from Citrus maxima (Burm.) Merr and sericin from Bombyx mori combination in the treatment of psoriasis. Inhibitory effects on the expression of mRNA and the production of pro-inflammatory cytokines (TNF-α, IL-6, IL-23, and IL-12p40) were investigated. METHODS: Human peripheral blood mononuclear cells (hPBMCs) were isolated from 10 healthy subjects and 10 patients with psoriasis. The hPBMCs from each group were exposed to naringin or sericin alone, and the combination of naringin and sericin. The expression levels of mRNA and the production of all cytokines were determined using quantitative RT-PCR and ELISA, respectively. RESULTS: Naringin/sericin combination significantly decreased the expression of mRNA and the production of all pro-inflammatory cytokines in hPBMCs from patients with psoriasis. The potency of inhibitory activity was markedly higher than naringin or sericin alone. CONCLUSION: The activity of naringin/sericin combination on down-regulation of these pro-inflammatory cytokines suggested its potential clinical use in psoriasis as well as other inflammation-associated diseases. The combination might be used as a complementary therapy with conventional treatment in psoriasis to improve clinical efficacy and tolerability.

Population pharmacokinetics of mefloquine given as a 3-day artesunate-mefloquine in patients with acute uncomplicated Plasmodium falciparum malaria in a multidrug-resistant area along the Thai-Myanmar border.

BACKGROUND: Low mefloquine exposure has been shown to contribute to treatment failure in patients with uncomplicated falciparum malaria following a 3-day artesunate-mefloquine combination. The present study aimed to develop a population pharmacokinetic model for mefloquine based on whole blood concentration-time profiles of this target population for further dose optimization. METHODS: A total of 129 Burmese patients aged above 15 years who presented with typical symptoms of malaria and had a blood smear positive for Plasmodium falciparum were included in the study. All were treated with the standard 3-day combination regimen of artesunate and mefloquine consisting of mefloquine for 2 days and artesunate for 3 days. Blood samples were collected before and at different time points after drug administration from different sub-groups of patients. Mefloquine concentrations were quantified in whole blood using high-performance liquid chromatography. A non-linear mixed-effect modelling approach was applied for population pharmacokinetic analysis using the NONMEM v7.3 software. Covariates investigated (body weight, gender, admission parasitaemia, and molecular markers of mefloquine resistance) were investigated in a step-wise manner using the SCM functionality in Perl-Speaks-NONMEM. RESULTS: Population pharmacokinetic analysis of mefloquine was performed in all patients with a total of 653 samples. Whole blood mefloquine concentration-time profiles were described by a two-compartment disposition model. Of the covariates investigated, none was found to have a significant impact on the pharmacokinetics of mefloquine. Significant differences in maximum concentration (Cmax) and elimination half-life (t1/2) were found in patients who had treatment failure (36 cases) compared to patients with successful treatment (107 cases). CONCLUSION: The study successfully describes the pharmacokinetics of mefloquine following a 2-day treatment of mefloquine as a part of a 3-day artesunate-mefloquine in patients with uncomplicated falciparum malaria from Thailand. A model has been developed which adequately describes the pharmacokinetics of mefloquine. More extensive clinical studies including both adults and children are needed to fully characterize the pharmacokinetics of mefloquine.

Cytotoxic activities and effects of atractylodin and ß-eudesmol on the cell cycle arrest and apoptosis on cholangiocarcinoma cell line.

Cholangiocarcinoma (CCA) is the cancer of bile duct with high mortality rate particularly in Thailand. The clinical efficacy of the standard chemotherapeutics remains unsatisfactory, and therefore, discovery and development of the new alternative drugs with high efficacy and tolerability is needed. The aim of the study was to investigate cytotoxic activity as well as the underlying mechanisms through which atractylodin and ß-eudesmol exert their activities on CCA cell growth inhibition, cell cycle arrest, and cell apoptosis. Effects of the compounds on cell cytotoxicity, cell cycle arrest, and cell apoptosis were analyzed using MTT assay, BD Cycletest™ Plus DNA kit, and FITC Annexin V Apoptosis Detection Kit I, respectively. The cytotoxic activities of both compounds were concentration- and time-dependent. The IC50 [mean (SD)] of atractylodin and ß-eudesmol were 41.66 (2.51) and 39.33 (1.15) µg/ml respectively. Both promoted cell cycle arrest at G1 phase, and induced cell apoptosis through activation of caspase-3/7. The highest activity was observed at 48 h of exposure. Results suggest that these mechanisms are at least in part, explain the cell cytotoxic and anti-CCA activity of atractylodin and ß-eudesmol shown in vitro and in vivo models.

Utility of physiologically based pharmacokinetic (PBPK) modeling in oncology drug development and its accuracy: a systematic review.

PURPOSE: Physiologically based pharmacokinetic (PBPK) modeling, a mathematical modeling approach which uses a pharmacokinetic model to mimick human physiology to predict drug concentration-time profiles, has been used for the discover and development of drugs in various fields, including oncology, since 2000. There have been a few general review articles on the utilization of PBPK in the development of oncology drugs, but these do not include an evaluation of model prediction accuracy. We therefore conducted a systematic review to define the accuracy of PBPK model prediction and its utility throughout all the developmental phases of oncology drugs. METHODS: A systematic search was performed in the PubMed, PubMed Central and Cochrane Library databases from 1980 to February 2017 for articles (1) written in English, (2) focused on oncology or antineoplastic or anticancer drugs, tumor or cancer or anticancer drugs listed in the U.S. National Institutes of Health and (3) involving a PBPK model. The absolute-average-folding-errors (AAFEs) of the area under the curve (AUC) between predicted and observed values in each article were calculated to assess model prediction accuracy. RESULTS: Of the 2341 articles initially identified by our search of the databases, 40 were included in the review analysis. These articles reported on six types of studies, i.e. in vivo (n = 4), first-in-human (n = 5), phase II/III clinical trials (n = 9), organ impairment (n = 3), pediatrics (n = 4) and drug-drug interactions (n = 15). AAFEs of the predicted AUC for all groups of studies were within 1.3-fold of each other despite variations in experimental methodologies. CONCLUSION: PBPK modeling is a potential tool which can be effectively applied throughout all phases of oncology drug development. The number of experimental animals and human participants enrolled in the studies can be reduced using PBPK modeling and PBPK-population-PK modeling. The limited number of publications of unsuccessful model application to date may contribute to bias toward the usefulness of modeling.

Evaluation of Plasmodium vivax isolates in Thailand using polymorphic markers Plasmodium merozoite surface protein (PvMSP) 1 and PvMSP3.

Malaria is a significant public health problem in several tropical countries including Thailand. The prevalence of Plasmodium vivax infection has been increasing in the past decades. Plasmodium vivax merozoite surface protein (PvMSP) gene encodes a malaria vaccine candidate antigen. Its polymorphic nature leads to antigenic variation, the barrier for vaccine development, drug resistance, and potential for multiple-clone infections within the malaria patients. The objective of this study was to investigate the genetic diversity of PvMSP1 and PvMSP3 gene in P. vivax populations in Thailand. A total of 100 P. vivax isolates collected from the western (Kanchanaburi and Tak Provinces) and southern (Ranong Provinces) regions along the Thai-Myanmar border were analyzed using polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP). Analysis of the F1, F2, and F3 regions of PvMSP1 revealed 5, 2, and 3 allelic variants, respectively. Three major types of PvMSP3-α and two major types of PvMSP3-ß were identified based on the PCR product sizes. After digestion with restriction enzymes, 29, 25, 26, and 18 patterns were distinguished by RFLP for PvMSP1 (F2, Alu I), PvMSP1 (F2, Mnl I), PvMSP3-α, and PvMSP3-ß, respectively. Combination of each family variant (PvMSP1 and PvMSP3) resulted in high genetic polymorphism of P. vivax population. Additionally, using PvMSP1 polymorphic marker revealed a significant association between multiple-genotype infections and P. vivax parasitemia. The results strongly supported that P. vivax populations in the endemic areas along the Thai-Myanmar border are highly diverse.

The Effect of ABO Blood Groups, Hemoglobinopathy, and Heme Oxygenase-1 Polymorphisms on Malaria Susceptibility and Severity.

Malaria is one of the most important public health problems in tropical areas on the globe. Several factors are associated with susceptibility to malaria and disease severity, including innate immunity such as blood group, hemoglobinopathy, and heme oxygenase-1 (HO-1) polymorphisms. This study was carried out to investigate association among ABO blood group, thalassemia types and HO-1 polymorphisms in malaria. The malarial blood samples were collected from patients along the Thai-Myanmar border. Determination of ABO blood group, thalassemia variants, and HO-1 polymorphisms were performed using agglutination test, low pressure liquid chromatography and polymerase chain reaction, respectively. Plasmodium vivax was the major infected malaria species in the study samples. Distribution of ABO blood type in the malaria-infected samples was similar to that in healthy subjects, of which blood type O being most prevalent. Association between blood group A and decreased risk of severe malaria was significant. Six thalassemia types (30%) were detected, i.e., hemoglobin E (HbE), ß-thalassemia, α-thalassemia 1, α-thalassemia 2, HbE with α-thalassemia 2, and ß-thalassemia with α-thalassemia 2. Malaria infected samples without thalassemia showed significantly higher risk to severe malaria. The prevalence of HO-1 polymorphisms, S/S, S/L and L/L were 25, 62, and 13%, respectively. Further study with larger sample size is required to confirm the impact of these 3 host genetic factors in malaria patients.