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Fulltext An update on HLA alleles as pharmacogenetic markers for antiepileptic drug-induced cutaneous adverse reaction

Then, Sue-Mian, Azman Ali Raymond

Neuroscience Research Notes, 2019;2(2):1-17.
MyJurnal

Epilepsy is a common neurological disorder affecting approximately 50 million people worldwide. Antiepileptic drugs (AEDs) are commonly used to treat the disease depending, mainlyon the type of seizure. However, the useof AEDs mayalso lead to cutaneous adverse drug reactions (cADR) such as toxic epidermal necrolysis (TEN), Stevens-Johnsonsyndrome (SJS), exfoliative dermatitis (ED) and drug‐induced hypersensitivity syndrome/drug reaction with eosinophilia and systemic symptoms (DIHS/DRESS), which are unwanted comorbidities in epilepsy. It was first discoveredthat the HLA-B*15:02 allele was strongly associatedwith carbamazepine(CBZ)-induced SJS/TEN amongHan Chinese and this ledto the discovery of other HLAallelesand cytochrome P450 (CYP) genes that were significantly associatedwith various AED-inducedcADRsacross variouspopulations. This mini-reviewis an update on the latest findings ofthe involvement of various HLA alleles and CYP alleles in cADRs caused by CBZ, phenytoin (PHT), oxcarbazepine (OXC) and lamotrigine(LTG) in different case-control studies around the world. From our review, we found that CBZ-and PHT-induced cADRsweremore commonly reportedthan the other AEDs.Therefore,there were morerobust pharmacogenetics studies related to these AEDs. OXC-and LTG-induced cADRswereless commonly reported,and somore studies are needed to validate the reported association of the newer reported HLA alleles with theseAEDs. It is also importantto considerthe allelic frequency within a given population before concludingthe use of thesealleles as genetic markers to prevent AED-induced cADR. Overall, the current body of research pointto a combination of alleles as a better pharmacogenetic marker comparedto the use of a single gene as a genetic marker for AED-induced cADR.
Fulltext Apolipoprotein E genotypes and behavioural and psychological symptoms of dementia (BPSD) in Malaysian patients with dementia

Rosdinom Razali, Zanariah Mat Saher, Elinda Tunan, Wan Zurinah Wan Ngah, Then Sue Mian, Suriati Mohamed Saini, et al.

Sains Malaysiana, 2013;42(3):409-416.

The aim of this study was to determine the relationships between ApoE genotypes and ‘behavioural and psychological symptoms of dementia’ (BPSD). A cross-sectional study was conducted on 46 outpatients with dementia (aged 60 and above) and their caregivers attending the psychogeriatric clinics at Universiti Kebangsaan Malaysia Medical Centre (UKMMC) and Hospital Kuala Lumpur. Neuropsychiatric Inventory (NPI) was used for the assessment of BPSD. The patients’ blood samples were taken for Apolipoprotein genotyping after consented by the caregivers. There were more female (69.6%) and Chinese (50%) patients with a mean age of 73.7 years. ApoE ε3/ε3 was the most common ApoE allele (60.7%) and mostly found in Chinese patients. ApoE genotype was significantly associated with ethnicity (p=0.03) and marital status (p=0.01). Alzheimer disease was the most common subtype of dementia (41.3%) and the highest carrier of ApoE ε3/ε3 (30.4%). The ApoE ε4/ ε4 scored highest in BPSD median score 44 (17.5 to 90) but the relationships
between ApoE genotypes and subtypes of dementia or BPSD scores were not significant (p=0.20; p=0.64). Agitation was the most common symptom, with delusions showing the highest scores on the NPI with no significant association to ApoE 4 allele. In conclusion, there was no significant relationship between ApoE genotypes and severity or types of BPSD in dementia patients.
Autogenic feeder free system from differentiated mesenchymal progenitor cells, maintains pluripotency of the MEL-1 human embryonic stem cells

Khoo TS, Hamidah Hussin N, Then SM, Jamal R

Differentiation, 2013 Feb;85(3):110-8.
PMID: 23722082 DOI: 10.1016/j.diff.2013.01.004

Human embryonic stem cells (hESc) are known for its pluripotency and self renewal capability, thus possess great potential in regenerative medicine. However, the lack of suitable xenofree extracellular matrix substrate inhibits further applications or the use of hESc in cell-based therapy. In this study, we described a new differentiation method, which generates a homogeneous population of mesenchymal progenitor cells (hESc-MPC) from hESc via epithelial-mesenchymal transition. The extracellular matrix (ECM) proteins from hESc-MPC had in turn supported the undifferentiated expansion of hESc. Immunocytochemistry and flow cytometry characterization of hESc-MPC revealed the presence of early mesenchymal markers. Tandem mass spectometry analysis of ECM produced by hESc-MPC revealed the presence of a mixture of extracellular proteins which includes tenascin C, fibronectin, and vitronectin. The pluripotency of hESc (MEL-1) cultured on the ECM was maintained as shown by the expression of pluripotent genes (FoxD3, Oct-4, Tdgf1, Sox-2, Nanog, hTERT, Rex1), protein markers (SSEA-3, SSEA-4, TRA-1-81, TRA-1-60, Oct-4) and the ability to differentiate into cells representative of ectoderm, endoderm and mesoderm. In summary, we have established a xeno-free autogenic feeder free system to support undifferentiated expansion of hESc, which could be of clinical relevance.
Is vitamin E toxic to neuron cells?

Then SM, Mazlan M, Mat Top G, Wan Ngah WZ

Cell Mol Neurobiol, 2009 Jun;29(4):485-96.
PMID: 19172392 DOI: 10.1007/s10571-008-9340-8

Besides acting as potent free radical scavengers, tocopherols and tocotrienols have been known to have non-antioxidant properties such as the involvement of alpha-tocopherol (alphaT) in PKC pathway and the anti-cancer properties of gamma-tocotrienol (gammaT3). This study aims to elucidate whether protective effects shown by alphaT and gammaT3 in H(2)O(2)-induced neuron cultures have anti-apoptotic or pro-apoptotic tendency toward the initiation of neuronal apoptosis. H(2)O(2) is used to induce apoptosis in primary cerebellar neuron cultures which is attenuated by pretreatment of alphaT or gammaT3 at concentrations < or =10 microM. Similar to our previous work, gammaT3 was found to be neurotoxic at concentrations > or =100 microM, whereas alphaT showed no neurotoxicity. Cellular uptake of gammaT3 was higher than that of alphaT. Treating cells simultaneously with either gammaT3 or alphaT and with then H(2)O(2) led to higher expression of Bax and Bcl-2 than in neurons exposed to H(2)O(2) alone. Analysis of Bcl-2/Bax ratio as 'survival index' showed that both pretreatment of gammaT3 and alphaT followed by H(2)O(2) increase the 'survival index' of Bcl-2/Bax ratio compared to H(2)O(2)-treated cells, while treatment of gammaT3 alone decrease the ratio compared to unchanged Bcl2/Bax ratio of similar treatment with alphaT alone. Similar treatment of gammaT3 decreased p53 expression and activates p38 MAPK phosphorylation, whereas alphaT did not alter its expression compared to H(2)O(2)-treated cells. Treating neurons with only gammaT3 or alphaT increased the expression of Bax, Bcl-2, p53, and p38 MAPK compared to control with gammaT3 exerting stronger expression for proteins involved than alphaT. In conclusion, low doses of gammaT3 and alphaT confer neuroprotection to H(2)O(2)-treated neurons via their antioxidant mechanism but gammaT3 has stronger pro-apoptosis tendency than alphaT by activating molecules involved in the neuronal apoptotic pathway in the absence of H(2)O(2).
Fulltext Pharmacogenomics screening of HLA-B*1502 in epilepsy patients: how we do it in the UKM Medical Centre, Malaysia

Then SM, Mohd Rani ZZ, Raymond AA, Jamal R

Neurology Asia, 2013;18(11):27-29.
MyJurnal

Previous studies have shown that carbamazepine-induced Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) patients is associated with the HLA-B*1502 allele. Screening for HLA-B*1502 before using carbamazepine can prevent SJS/TEN particularly in populations with high frequency of the allele. The objective of this paper was to describe how the UKM Medical Centre, Malaysia was able to set up a cost effective screening of HLA-B*1502 for patients taking carbamazepine. The cost of in-house HLA-B⁄1502 screening was less than those commercially available, and was sensitive and specific.
Fulltext An international collaborative approach to learning histology using a virtual microscope

Then SM, Kokolski M, Mbaki Y, Merrick D, Anderson S

Anat Histol Embryol, 2023 Jan;52(1):21-30.
PMID: 36373558 DOI: 10.1111/ahe.12888

Histology is often taught in higher education settings using online virtual microscopes (VM). This study aimed to develop and evaluate the use of VM in teaching on a BSc degree at the University of Nottingham by surveying students and staff. A key development was the use of an e-workbook so that students were actively engaged in creating their own bespoke revision material. Subsequently, this approach was used in a second study evaluating the use of VM in teaching the histology and pathology of the gastrointestinal (GI) tract via group work with students from two BSc courses at the University of Nottingham; one based at Derby (RDHC) and the other in Malaysia (UNMC). Students worked together in groups to complete an e-workbook, develop a presentation, and decide how to collaborate and communicate. An evaluation of these activities revealed advantages in developing transferrable skills, and good engagement with both the histology topic and group work. Analysis of assessment of the module at UNMC showed that student performance improved in the histology-based module after the intervention (p
Fulltext γ-Tocotrienol does not substantially protect DS neurons from hydrogen peroxide-induced oxidative injury

Then SM, Sanfeliu C, Top GM, Wan Ngah WZ, Mazlan M

Nutr Metab (Lond), 2012;9:1.
PMID: 22217149 DOI: 10.1186/1743-7075-9-1

Down syndrome (DS) neurons are more susceptible to oxidative stress and previous studies have shown that vitamin E was able to reduce oxidative stress and improve DS neurons' viability. Therefore, this study was done to investigate the protective role of γ-tocotrienol (γT3) in DS neurons from hydrogen peroxide (H2O2) -induced oxidative stress. The pro-apoptosis tendency of γT3 was compared to α-tocopherol (αT) in non-stress condition as well.
Frequency of the HLA-B*1502 allele contributing to carbamazepine-induced hypersensitivity reactions in a cohort of Malaysian epilepsy patients

Then SM, Rani ZZ, Raymond AA, Ratnaningrum S, Jamal R

Asian Pac J Allergy Immunol, 2011 Sep;29(3):290-3.
PMID: 22053601

We describe the association of the HLA-B*1502 allele in 27 epilepsy patients (19 Malays, 8 Chinese) treated with carbamazepine (CBZ) at the UKM Medical Center (UKMMC), 6 with CBZ-Steven Johnson Syndrome (CBZ-SJS), 11 with CBZ-induced rash, 2 with suspected phenytoin-induced rash and 8 negative controls. Our study showed that 10 (6 Malay, 4 Chinese) patients were positive for HLA-B*1502. Out of the 10 patients, six were confirmed to have CBZ-SJS (p = 0.0006), while four patients developed a skin rash. However there were 6 Malay patients and 1 Chinese patient that developed a skin rash after CBZ administration who were not positive for the allele, indicating that there might be more that one allele associated with CBZ-induced hypersensitivity. Another 2 patients were suspected of having phenytoin-induced rash, instead of CBZ, and these patients did not have HLA-B*1502. In conclusion, this study confirmed the association of HLA-B*1502 with CBZ-SJS among Malaysian epilepsy patients, however there might be other genes that could be responsible for the CBZ-induced rash.
Vitamin E, γ-tocotrienol, Protects Against Buthionine Sulfoximine-Induced Cell Death by Scavenging Free Radicals in SH-SY5Y Neuroblastoma Cells

Tan JK, Then SM, Mazlan M, Jamal R, Ngah WZ

Nutr Cancer, 2016 Apr;68(3):507-17.
PMID: 27008382 DOI: 10.1080/01635581.2016.1153671

The induction of reactive oxygen species (ROS) to selectively kill cancer cells is an important feature of radiotherapy and various chemotherapies. Depletion of glutathione can induce apoptosis in cancer cells or sensitize them to anticancer treatments intended to modulate ROS levels. In contrast, antioxidants protect cancer cells from oxidative stress-induced cell death by scavenging ROS. The role of exogenous antioxidants in cancer cells under oxidative insults remains controversial and unclear. This study aimed to identify protective pathways modulated by γ-tocotrienol (γT3), an isomer of vitamin E, in human neuroblastoma SH-SY5Y cells under oxidative stress. Using buthionine sulfoximine (BSO) as an inhibitor of glutathione synthesis, we found that BSO treatment reduced the viability of SH-SY5Y cells. BSO induced cell death by increasing apoptosis, decreased the level of reduced glutathione (GSH), and increased ROS levels in SH-SY5Y cells. Addition of γT3 increased the viability of BSO-treated cells, suppressed apoptosis, and decreased the ROS level induced by BSO, while the GSH level was unaffected. These results suggest that decreasing GSH levels by BSO increased ROS levels, leading to apoptosis in SH-SY5Y cells. γT3 attenuated the BSO-induced cell death by scavenging free radicals.
Gamma-tocotrienol acts as a BH3 mimetic to induce apoptosis in neuroblastoma SH-SY5Y cells

Tan JK, Then SM, Mazlan M, Raja Abdul Rahman RN, Jamal R, Wan Ngah WZ

J Nutr Biochem, 2016 May;31:28-37.
PMID: 27133421 DOI: 10.1016/j.jnutbio.2015.12.019

Bcl-2 family proteins are crucial regulators of apoptosis. Both pro- and antiapoptotic members exist, and overexpression of the latter facilitates evasion of apoptosis in many cancer types. Bcl-2 homology domain 3 (BH3) mimetics are small molecule inhibitors of antiapoptotic Bcl-2 family members, and these inhibitors are promising anticancer agents. In this study, we report that gamma-tocotrienol (γT3), an isomer of vitamin E, can inhibit Bcl-2 to induce apoptosis. We demonstrate that γT3 induces cell death in human neuroblastoma SH-SY5Y cells by depolarising the mitochondrial membrane potential, enabling release of cytochrome c to the cytosol and increasing the activities of caspases-9 and -3. Treatment of cells with inhibitors of Bax or caspase-9 attenuated the cell death induced by γT3. Simulated docking analysis suggested that γT3 binds at the hydrophobic groove of Bcl-2, while a binding assay showed that γT3 competed with a fluorescent probe to bind at the hydrophobic groove. Our data suggest that γT3 mimics the action of BH3-only protein by binding to the hydrophobic groove of Bcl-2 and inducing apoptosis via the intrinsic pathway in a Bax- and caspase-9-dependent manner.
The role of long chain omega-3 polyunsaturated fatty acids in reducing lipid peroxidation among elderly patients with mild cognitive impairment: a case-control study

Lee LK, Shahar S, Rajab N, Yusoff NA, Jamal RA, Then SM

J Nutr Biochem, 2013 May;24(5):803-8.
PMID: 22898566 DOI: 10.1016/j.jnutbio.2012.04.014

The present work explores the effect of dietary omega-3 polyunsaturated fatty acids (PUFAs) intake on lipid peroxidation among mild cognitive impairment (MCI) patients. The plasma lipid hydroperoxide (LPO) levels in 67 MCI patients were compared to those of 134 healthy elderly controls. Omega-3 PUFA intake was assessed using an interviewer-administered food frequency questionnaire. Apolipoprotein E genotyping was performed using polymerase chain reaction and restriction enzyme digestion. The association between various confounders and lipid peroxidation was evaluated using regression analysis. The influence of docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) intake on LPO level was investigated. The results revealed that LPO levels were significantly higher in the MCI group than in the control group. Inverse correlations were found between DHA and EPA intake and LPO level among the MCI group. LPO levels decreased significantly with increasing DHA and EPA intake. In summary, the findings revealed that DHA and EPA can play a role in alleviating oxidative stress and reducing the risk of neurodegenerative diseases.
Cis-9, Trans-11 Conjugated Linoleic Acid Reduces Phosphoenolpyruvate Carboxykinase Expression and Hepatic Glucose Production in HepG2 Cells

Chai BK, Al-Shagga M, Pan Y, Then SM, Ting KN, Loh HS, et al.

Lipids, 2019 06;54(6-7):369-379.
PMID: 31124166 DOI: 10.1002/lipd.12154

Dysregulated hepatic gluconeogenesis is a hallmark of insulin resistance and type 2 diabetes mellitus (T2DM). Although existing drugs have been proven to improve gluconeogenesis, achieving this objective with functional food is of interest, especially using conjugated linoleic acid (CLA) found in dairy products. Both cis-9, trans-11 (c9,t11) and trans-10, cis-12 (t10,c12) isomers of CLA were tested in human (HepG2) and rat (H4IIE) hepatocytes for their potential effects on gluconeogenesis. The hepatocytes exposed for 24 h with 20 μM of c9,t11-CLA had attenuated the gluconeogenesis in both HepG2 and H4IIE by 62.5% and 80.1%, respectively. In contrast, t10,c12-CLA had no effect. Of note, in HepG2 cells, the exposure of c9,t11-CLA decreased the transcription of gluconeogenic enzymes, cytosolic phosphoenolpyruvate carboxykinase (PCK1) by 87.7%, and glucose-6-phosphatase catalytic subunit (G6PC) by 38.0%, while t10,c12-CLA increased the expression of G6PC, suggesting the isomer-specific effects of CLA on hepatic glucose production. In HepG2, the peroxisome proliferator-activated receptor (PPAR) agonist, rosiglitazone, reduced the glucose production by 72.9%. However, co-administration of c9,t11-CLA and rosiglitazone neither exacerbated nor attenuated the efficacy of rosiglitazone to inhibit glucose production; meanwhile, t10,c12-CLA abrogated the efficacy of rosiglitazone. Paradoxically, PPARγ antagonist GW 9662 also led to 70.2% reduction of glucose production and near undetectable PCK1 expression by abrogating CLA actions. Together, while the precise mechanisms by which CLA isomers modulate hepatic gluconeogenesis directly or via PPAR warrant further investigation, our findings establish that c9,t11-CLA suppresses gluconeogenesis by decreasing PEPCK on hepatocytes.
Fulltext Piper betle leaf extract enhances the cytotoxicity effect of 5-fluorouracil in inhibiting the growth of HT29 and HCT116 colon cancer cells

Ng PL, Rajab NF, Then SM, Mohd Yusof YA, Wan Ngah WZ, Pin KY, et al.

J Zhejiang Univ Sci B, 2014 Aug;15(8):692-700.
PMID: 25091987 DOI: 10.1631/jzus.B1300303

OBJECTIVE: The combination effect of Piper betle (PB) and 5-fluorouracil (5-FU) in enhancing the cytotoxic potential of 5-FU in inhibiting the growth of colon cancer cells was investigated.
METHODS: HT29 and HCT116 cells were subjected to 5-FU or PB treatment. 5-FU and PB were then combined and their effects on both cell lines were observed after 24 h of treatment. PB-5-FU interaction was elucidated by isobologram analysis. Apoptosis features of the treated cells were revealed by annexin V/PI stain. High-performance liquid chromatography (HPLC) was performed to exclude any possible chemical interaction between the compounds.
RESULTS: In the presence of PB extract, the cytotoxicity of 5-FU was observed at a lower dose (IC50 12.5 µmol/L) and a shorter time (24 h) in both cell lines. Both cell lines treated with 5-FU or PB alone induced a greater apoptosis effect compared with the combination treatment. Isobologram analysis indicated that PB and 5-FU interacted synergistically and antagonistically in inhibiting the growth of HT29 and HCT116 cells, respectively.
CONCLUSIONS: In the presence of PB, a lower dosage of 5-FU is required to achieve the maximum drug effect in inhibiting the growth of HT29 cells. However, PB did not significantly reduce 5-FU dosage in HCT116 cells. Our result showed that this interaction may not solely contribute to the apoptosis pathway.
KEYWORDS: 5-Fluorouracil; Herb-drug interaction; Isobologram analysis; Piper betle L.; Piperaceae
Bronchodilator effects of Lignosus rhinocerotis extract on rat isolated airways is linked to the blockage of calcium entry

Lee MK, Lim KH, Millns P, Mohankumar SK, Ng ST, Tan CS, et al.

Phytomedicine, 2018 Mar 15;42:172-179.
PMID: 29655683 DOI: 10.1016/j.phymed.2018.03.025

BACKGROUND: Lignosus rhinocerotis (Cooke) Ryvarden is a popular medicinal mushroom used for centuries in Southeast Asia to treat asthma and chronic cough. The present study aimed to investigate the effect of this mushroom on airways patency.
MATERIALS AND METHODS: The composition of L. rhinocerotis TM02 cultivar was analyzed. Organ bath experiment was employed to study the bronchodilator effect of Lignosus rhinocerotis cold water extract (CWE) on rat isolated airways. Trachea and bronchus were removed from male Sprague-Dawley rats, cut into rings of 2 mm, pre-contracted with carbachol before adding CWE into the bath in increasing concentrations. To investigate the influence of incubation time, tissues were exposed to intervals of 5, 15 and 30 min between CWE concentrations after pre-contraction with carbachol in subsequent protocol. Next, tissues were pre-incubated with CWE before the addition of different contractile agents, carbachol and 5-hydroxytrptamine (5-HT). The bronchodilator effect of CWE was compared with salmeterol and ipratropium. In order to uncover the mechanism of action of CWE, the role of beta-adrenoceptor, potassium and calcium channels was investigated.
RESULTS: Composition analysis of TM02 cultivar revealed the presence of β-glucans and derivatives of adenosine. The extract fully relaxed the trachea at 3.75 mg/ml (p 
Fulltext Data on the Lignosus rhinocerotis water soluble sclerotial extract affecting intracellular calcium level in rat dorsal root ganglion cells

Lee MK, Millns P, Mbaki Y, Ng ST, Tan CS, Lim KH, et al.

Data Brief, 2018 Jun;18:1322-1326.
PMID: 29900310 DOI: 10.1016/j.dib.2018.04.033

The data in this article contain supporting evidence for the research manuscript entitled "Bronchodilator effects of Lignosus rhinocerotis extract on rat isolated airways is linked to the blockage of calcium entry" by Lee et al. (2018) [1]. The data were obtained by calcium imaging technique with fluorescent calcium indicator dyes, Fura 2-AM, to visualize calcium ion movement in the rat dorsal ganglion (DRG) cells. The effects of L. rhinocerotis cold water extract (CWE1) on intracellular calcium levels in the DRG cells were presented.
Effects of simulated microgravity on gene expression and biological phenotypes of a single generation Caenorhabditis elegans cultured on 2 different media

Tee LF, Neoh HM, Then SM, Murad NA, Asillam MF, Hashim MH, et al.

Life Sci Space Res (Amst), 2017 Nov;15:11-17.
PMID: 29198309 DOI: 10.1016/j.lssr.2017.06.002

Studies of multigenerational Caenorhabditis elegans exposed to long-term spaceflight have revealed expression changes of genes involved in longevity, DNA repair, and locomotion. However, results from spaceflight experiments are difficult to reproduce as space missions are costly and opportunities are rather limited for researchers. In addition, multigenerational cultures of C. elegans used in previous studies contribute to mixture of gene expression profiles from both larvae and adult worms, which were recently reported to be different. Usage of different culture media during microgravity simulation experiments might also give rise to differences in the gene expression and biological phenotypes of the worms. In this study, we investigated the effects of simulated microgravity on the gene expression and biological phenotype profiles of a single generation of C. elegans worms cultured on 2 different culture media. A desktop Random Positioning Machine (RPM) was used to simulate microgravity on the worms for approximately 52 to 54 h. Gene expression profile was analysed using the Affymetrix GeneChip® C. elegans 1.0 ST Array. Only one gene (R01H2.2) was found to be downregulated in nematode growth medium (NGM)-cultured worms exposed to simulated microgravity. On the other hand, eight genes were differentially expressed for C. elegans Maintenance Medium (CeMM)-cultured worms in microgravity; six were upregulated, while two were downregulated. Five of the upregulated genes (C07E3.15, C34H3.21, C32D5.16, F35H8.9 and C34F11.17) encode non-coding RNAs. In terms of biological phenotype, we observed that microgravity-simulated worms experienced minimal changes in terms of lifespan, locomotion and reproductive capabilities in comparison with the ground controls. Taking it all together, simulated microgravity on a single generation of C. elegans did not confer major changes to their gene expression and biological phenotype. Nevertheless, exposure of the worms to microgravity lead to higher expression of non-coding RNA genes, which may play an epigenetic role in the worms during longer terms of microgravity exposure.
Fulltext Mitochondrial DNA Mutations in Grade II and III Glioma Cell Lines Are Associated with Significant Mitochondrial Dysfunction and Higher Oxidative Stress

Soon BH, Abdul Murad NA, Then SM, Abu Bakar A, Fadzil F, Thanabalan J, et al.

Front Physiol, 2017;8:231.
PMID: 28484394 DOI: 10.3389/fphys.2017.00231

The role of mitochondria in tumorigenesis has regained much attention as it could dysregulate cellular energetics, oxidative stress and apoptosis. However, the role of mitochondria in different grade gliomasis still unknown. This study aimed to identify mitochondrial DNA (mtDNA) sequence variations that could possibly affect the mitochondrial functions and also the oxidative stress status. Three different grades of human glioma cell lines and a normal human astrocyte cell line were cultured in-vitro and tested for oxidative stress biomarkers. Relative oxidative stress level, mitochondria activity, and mitochondrial mass were determined by live cell imaging with confocal laser scanning microscope using CM-H2DCFDA, MitoTracker Green, and MitoTracker Orange stains. The entire mitochondrial genome was sequenced using the AffymetrixGeneChip Human Mitochondrial Resequencing Array 2.0. The mitochondrial sequence variations were subjected to phylogenetic haplogroup assessment and pathogenicity of the mutations were predicted using pMUT and PolyPhen2. The Grade II astrocytoma cells showed increased oxidative stress wherea high level of 8-OHdG and oxidative stress indicator were observed. Simultaneously, Grade II and III glioma cells showed relatively poor mitochondria functions and increased number of mutations in the coding region of the mtDNA which could be due to high levels of oxidative stress in these cells. These non-synonymous mtDNA sequence variations were predicted to be pathogenic and could possibly lead to protein dysfunction, leading to oxidative phosphorylation (OXPHOS) impairment, mitochondria dysfunction and could create a vicious cycle of oxidative stress. The Grade IV cells had no missense mutation but preserved intact mitochondria and excellent antioxidant defense mechanisms thus ensuring better survival. In conclusion, Grade II and III glioma cells demonstrated coding region mtDNA mutations, leading to mitochondrial dysfunction and higher oxidative stress.
Fulltext Implementing HLA-B*58:01 testing prior to allopurinol initiation in Malaysian primary care setting: A qualitative study from doctors' and patients' perspective

Ng WL, Hussein N, Ng CJ, Qureshi N, Lee YK, Kwan Z, et al.

PLoS One, 2024;19(1):e0296498.
PMID: 38206925 DOI: 10.1371/journal.pone.0296498

INTRODUCTION: Allopurinol, the first-line treatment for chronic gout, is a common causative drug for severe cutaneous adverse reactions (SCAR). HLA-B*58:01 allele was strongly associated with allopurinol-induced SCAR in Asian countries such as Taiwan, Japan, Thailand and Malaysia. HLA-B*58:01 screening before allopurinol initiation is conditionally recommended in the Southeast-Asian population, but the uptake of this screening is slow in primary care settings, including Malaysia. This study aimed to explore the views and experiences of primary care doctors and patients with gout on implementing HLA-B*58:01 testing in Malaysia as part of a more extensive study exploring the feasibility of implementing it routinely.
METHODS: This qualitative study used in-depth interviews and focus group discussions to obtain information from patients with gout under follow-up in primary care and doctors who cared for them. Patients and doctors shared their gout management experiences and views on implementing HLA-B*58:01 screening in primary care. Data were coded and analysed using thematic analysis.
RESULTS: 18 patients and 18 doctors from three different healthcare settings (university hospital, public health clinics, private general practitioner clinics) participated. The acceptability to HLA-B*58:01 screening was good among the doctors and patients. We discovered inadequate disclosure of severe side effects of allopurinol by doctors due to concerns about medication refusal by patients, which could potentially be improved by introducing HLA-B*58:01 testing. Barriers to implementation included out-of-pocket costs for patients, the cost-effectiveness of this implementation, lack of established alternative treatment pathway besides allopurinol, counselling burden and concern about genetic data security. Our participants preferred targeted screening for high-risk populations instead of universal screening.
CONCLUSION: Implementing HLA-B*58:01 testing in primary care is potentially feasible if a cost-effective, targeted screening policy on high-risk groups can be developed. A clear treatment pathway for patients who test positive should be made available.
Somatic mitochondrial DNA mutations in different grades of glioma

Soon BH, Abu N, Abdul Murad NA, Then SM, Abu Bakar A, Fadzil F, et al.

Per Med, 2022 01;19(1):25-39.
PMID: 34873928 DOI: 10.2217/pme-2021-0033

Aim: Mitochondrial DNA (mtDNA) alterations play an important role in the multistep processes of cancer development. Gliomas are among the most diagnosed brain cancer. The relationship between mtDNA alterations and different grades of gliomas are still elusive. This study aimed to elucidate the profile of somatic mtDNA mutations in different grades of gliomas and correlate it with clinical phenotype. Materials & methods: Forty histopathologically confirmed glioma tissue samples and their matched blood were collected and subjected for mtDNA sequencing. Results & conclusion: About 75% of the gliomas harbored at least one somatic mutation in the mtDNA gene, and 45% of these mutations were pathogenic. Mutations were scattered across the mtDNA genome, and the commonest nonsynonymous mutations were located at complex I and IV of the mitochondrial respiratory chain. These findings may have implication for future research to determine the mitochondrial energetics and its downstream metabolomics on gliomas.
Prevalence of HLA-B*58:01 allele among Malay, Chinese and Indian ethnic patients with gout attending primary care clinics in Malaysia

Ng WL, Kee BP, Hussein N, Ng CJ, Kuan SW, Mohd Zaidan FZ, et al.

J Community Genet, 2024 Nov 25.
PMID: 39586937 DOI: 10.1007/s12687-024-00753-4

HLA-B*58:01 allele is associated with allopurinol-induced severe cutaneous reaction (SCAR). Malaysia has a multiethnic population with limited data on the prevalence of HLA-B*58:01 among patients with gout treated in primary care settings. This cross-sectional study aimed to determine the prevalence of HLA-B*5801 in patients with gout from the Malay, Chinese and Indian ethnicities attending primary clinics in Malaysia.We collected blood samples from patients with gout attending three primary care clinics in Klang Valley, Malaysia, using convenience sampling. Genomic DNA samples were subjected to typing of HLA-B*5801 by a multiplex probe-based assay in a real-time PCR system, validated by PCR-resequencing approach.547 patients (194 Malay, 266 Chinese and 87 Indian) were recruited. The overall prevalence of HLA-B*58:01 was 16.8% (Chinese 21.8%, Indian 12.6% and Malay 11.9%). None of our 61 HLA-B*58:01 carriers who ever used allopurinol developed SCAR.The overall prevalence of HLA-B*58:01 allele in our patients with gout was high, particularly among the Chinese ethnicity (21.8%). None of our HLA-B*58:01 positive patients treated with allopurinol reported allopurinol-induced SCAR. A more accurate predictive model for allopurinol-induced SCAR is needed.

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