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  1. 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.
  2. Vitamin E, glutathione S-transferase and gamma-glutamyl transpeptidase activities in cultured hepatocytes of rats treated with carcinogens
    Ong FB, Wan Ngah WZ, Top AG, Khalid BA, Shamaan NA
    Int. J. Biochem., 1994 Mar;26(3):397-402.
    PMID: 7910569
    1. The effects of alpha-tocopherol and gamma-tocotrienol on glutathione S-transferase (GST) and gamma-glutamyl transpeptidase (gamma-GT) activities in cultured hepatocytes prepared from rats treated with diethylnitrosamine (DEN) and 2-acetylaminofluorene (AAF) were investigated. 2. Both the alpha-tocopherol and gamma-tocotrienol treated hepatocytes showed significantly higher (P < 0.05) GST activities than untreated hepatocytes prepared from the carcinogen treated rats in the first 3 days of culture. Treatment with alpha-tocopherol and gamma-tocotrienol generally resulted in a tendency to increase the GST activities above that in the untreated hepatocytes. 3. Treatment with high doses (125-250 microM) of alpha-tocopherol and low doses (12.5-25 microM) of gamma-tocotrienol generally resulted in a significant reduction in gamma-GT activities at 1-3 days. gamma-GT activities are reduced as the dose of alpha-tocopherol and gamma-tocotrienol are increased.
  3. Fulltext Vitamin D status in Malaysian men and its associated factors
    Chin KY, Ima-Nirwana S, Ibrahim S, Mohamed IN, Wan Ngah WZ
    Nutrients, 2014 Nov 26;6(12):5419-33.
    PMID: 25431881 DOI: 10.3390/nu6125419
    Vitamin D insufficiency is a global health problem. The data on vitamin D status in Malaysian men is insufficient. This study aimed to investigate vitamin D status among Chinese and Malay men in Malaysia and its associating factors. A cross-sectional study was conducted on 383 men aged 20 years and above, residing in Klang Valley, Malaysia. Their age, ethnicity, body anthropometry and calcaneal speed of sound (SOS) were recorded. Their fasting blood was collected for serum 25-hydroxyvitamin D (25(OH)D), intact parathyroid (PTH), total calcium and inorganic phosphate assays. Vitamin D deficiency was defined as a serum 25(OH)D level <30 nmol/L and insufficiency as a serum 25(OH)D level between 30 and 50 nmol/L. The overall prevalence of vitamin D deficiency was 0.5%, and insufficiency was 22.7%. Vitamin D deficiency and insufficiency were more prevalent in the Malays compared to the Chinese. Being Chinese, older in age, having lower body mass index (BMI) and a high physical activity status were associated significantly with a higher serum 25(OH)D level (p < 0.05). The serum PTH level was inversely associated with the serum 25(OH)D level (p < 0.05). As a conclusion, a significant proportion of Malaysian men have vitamin D insufficiency, although deficiency is uncommon. Steps should be taken to correct the vitamin D status of these men.
  4. Vitamin D is significantly associated with total testosterone and sex hormone-binding globulin in Malaysian men
    Chin KY, Ima-Nirwana S, Wan Ngah WZ
    Aging Male, 2015;18(3):175-9.
    PMID: 26004987 DOI: 10.3109/13685538.2015.1034686
    OBJECTIVE: Cross-sectional studies in the Caucasian population have shown a significant relationship between vitamin D and testosterone levels, but data in the Asian population are limited. This study aimed to determine the association between vitamin D and testosterone levels in Malaysian men.

    METHODS: Chinese and Malay men (n = 382) aged 20 years or above residing in the Klang Valley, Malaysia were recruited. Their fasting blood was collected for serum testosterone, sex hormone-binding globulin (SHBG) and 25-hydroxyvitamin D (25(OH)D) assays. Relationship between 25(OH)D and testosterone levels was analyzed using multiple regression analysis. Testosterone and SHBG levels among subjects with different vitamin D status were compared using univariate analysis. Confounders such as age, ethnicity and body mass index (BMI) were adjusted.

    RESULTS: 25(OH)D was significantly and positively associated with total testosterone and SHBG levels before and after adjustment for age and ethnicity (p  0.05).

    CONCLUSION: 25(OH)D is significantly associated with total testosterone and SHBG in Malaysian men but this association is BMI-dependent.

  5. Fulltext Vascular Dysfunction among Malaysian Men with Increased BMI: An Indication of Synergistic Effect of Free Testosterone and Inflammation
    Aminuddin A, Salamt N, Ahmad Fuad AF, Chin KY, Ugusman A, Soelaiman IN, et al.
    Medicina (Kaunas), 2019 Sep 08;55(9).
    PMID: 31500378 DOI: 10.3390/medicina55090575
    Background and objectives: Obesity is associated with poor vascular function and may lead to future cardiovascular disease (CVD). Obesity is also related to increased inflammation and a low testosterone level. This study was conducted to determine the relationship between inflammation, testosterone level, and vascular function among subjects with an increased body mass index (BMI) and to determine whether both low testosterone and high inflammation have synergistic effects towards vascular dysfunction. Materials and Methods: A total of 303 men aged 40-80 years were recruited from Klang Valley, Malaysia. Their height, weight, blood pressure (BP), lipid, blood glucose level, total testosterone (TT), free testosterone (FT), and C-reactive protein (CRP) were measured. The carotid femoral pulse wave velocity (PWVCF) and augmentation index (AI) were also recorded as markers of vascular function. Results: The mean age of all the subjects was 54.46 ± 9.77 years. Subjects were divided into a low/normal body mass index (BMI) group (BMI < 25 kg/m2; NG, n = 154) and high BMI group (BMI ≥ 25 kg/m2; OG, n = 149). The mean BMI for NG was 22.20 ± 1.94 kg/m2 while for OG was 28.87 ± 3.24 kg/m2 (p < 0.01). The level of TT (OG = 21.13 ± 6.44 versus NG = 16.18 ± 6.16 nmol/L, p < 0.01) and FT (OG = 0.34 ± 0.12 versus NG = 0.39 ± 0.11 nmol/L, p < 0.01) were reduced while the level of CRP [OG = 1.05 (2.80) versus NG = 0.50 (1.50) mmol/L, p = 0.01] was increased in OG compared to NG. PWVCF (OG = 8.55 ± 1.34 versus NG = 8.52 ± 1.42 m/s, p = 0.02) and AI (OG = 16.91% ± 6.00% versus 15.88% ± 5.58%, p < 0.01) were significantly increased in OG after adjustment for other CVD risk factors. The subjects that had both a low FT and an increased CRP had higher AI when compared to those with a high CRP and high FT (p < 0.01). Conclusions: The increased BMI was associated with vascular dysfunction, mediated by a low testosterone level and increased inflammation. Furthermore, having both conditions concurrently lead to higher vascular dysfunction. Weight loss, testosterone supplementation, and the anti-inflammatory agent may be beneficial for men to prevent vascular dysfunction.
  6. Transcriptome analysis reveals the molecular mechanisms of combined gamma-tocotrienol and hydroxychavicol in preventing the proliferation of 1321N1, SW1783, and LN18 glioma cancer cells
    Abdul Rahman A, Mokhtar NM, Harun R, Jamal R, Wan Ngah WZ
    J Physiol Biochem, 2019 Nov;75(4):499-517.
    PMID: 31414341 DOI: 10.1007/s13105-019-00699-z
    Gamma-tocotrienol (GTT) and hydroxychavicol (HC) exhibit anticancer activity in glioma cancer cells, where the combination of GTT + HC was shown to be more effective than single agent. The aim of this study was to determine the effect of GTT + HC by measuring the cell cycle progression, migration, invasion, and colony formation of glioma cancer cells and elucidating the changes in gene expression mitigated by GTT + HC that are critical to the chemoprevention of glioma cell lines 1321N1 (grade II), SW1783 (grade III), and LN18 (grade IV) using high-throughput RNA sequencing (RNA-seq). Results of gene expression levels and alternative splicing transcripts were validated by qPCR. Exposure of glioma cancer cells to GTT + HC for 24 h promotes cell cycle arrest at G2M and S phases and inhibits cell migration, invasion, and colony formation of glioma cancer cells. The differential gene expression induced by GTT + HC clustered into response to endoplasmic reticulum (ER) stress, cell cycle regulations, apoptosis, cell migration/invasion, cell growth, and DNA repair. Subnetwork analysis of genes altered by GTT + HC revealed central genes, ATF4 and XBP1. The modulation of EIF2AK3, EDN1, and FOXM1 were unique to 1321N1, while CSF1, KLF4, and FGF2 were unique to SW1783. PLK2 and EIF3A gene expressions were only altered in LN18. Moreover, GTT + HC treatment dynamically altered transcripts and alternative splicing expression. GTT + HC showed therapeutic potential against glioma cancer as evident by the inhibition of cell cycle progression, migration, invasion, and colony formation of glioma cancer cells, as well as the changes in gene expression profiles with key targets in ER unfolded protein response pathway, apoptosis, cell cycle, and migration/invasion.
  7. Tocotrienol-rich fraction prevents cellular aging by modulating cell proliferation signaling pathways
    Khor SC, Mohd Yusof YA, Wan Ngah WZ, Makpol S
    Clin Ter, 2015;166(2):e81-90.
    PMID: 25945449 DOI: 10.7417/CT.2015.1825
    BACKGROUND AND OBJECTIVE: Vitamin E has been suggested as nutritional intervention for the prevention of degenerative and age-related diseases. In this study, we aimed to elucidate the underlying mechanism of tocotrienol-rich fraction (TRF) in delaying cellular aging by targeting the proliferation signaling pathways in human diploid fibroblasts (HDFs).

    MATERIALS AND METHODS: Tocotrienol-rich fraction was used to treat different stages of cellular aging of primary human diploid fibroblasts viz. young (passage 6), pre-senescent (passage 15) and senescent (passage 30). Several selected targets involved in the downstream of PI3K/AKT and RAF/MEK/ERK pathways were compared in total RNA and protein.

    RESULTS: Different transcriptional profiles were observed in young, pre-senescent and senescent HDFs, in which cellular aging increased AKT, FOXO3, CDKN1A and RSK1 mRNA expression level, but decreased ELK1, FOS and SIRT1 mRNA expression level. With tocotrienol-rich fraction treatment, gene expression of AKT, FOXO3, ERK and RSK1 mRNA was decreased in senescent cells, but not in young cells. The three down-regulated mRNA in cellular aging, ELK1, FOS and SIRT1, were increased with tocotrienol-rich fraction treatment. Expression of FOXO3 and P21Cip1 proteins showed up-regulation in senescent cells but tocotrienol-rich fraction only decreased P21Cip1 protein expression in senescent cells.

    CONCLUSIONS: Tocotrienol-rich fraction exerts gene modulating properties that might be responsible in promoting cell cycle progression during cellular aging.

  8. Fulltext Tocotrienol-Rich Fraction of Palm Oil Improves Behavioral Impairments and Regulates Metabolic Pathways in AβPP/PS1 Mice
    Durani LW, Hamezah HS, Ibrahim NF, Yanagisawa D, Nasaruddin ML, Mori M, et al.
    J Alzheimers Dis, 2018;64(1):249-267.
    PMID: 29889072 DOI: 10.3233/JAD-170880
    We have recently shown that the tocotrienol-rich fraction (TRF) of palm oil, a mixture of vitamin E analogs, improves amyloid pathology in vitro and in vivo. However, precise mechanisms remain unknown. In this study, we examined the effects of long-term (10 months) TRF treatment on behavioral impairments and brain metabolites in (15 months old) AβPP/PS1 double transgenic (Tg) Alzheimer's disease (AD) mice. The open field test, Morris water maze, and novel object recognition tasks revealed improved exploratory activity, spatial learning, and recognition memory, respectively, in TRF-treated Tg mice. Brain metabolite profiling of wild-type and Tg mice treated with and without TRF was performed using ultrahigh performance liquid chromatography (UHPLC) coupled to high-resolution accurate mass (HRAM)-orbitrap tandem mass spectrometry (MS/MS). Metabolic pathway analysis found perturbed metabolic pathways that linked to AD. TRF treatment partly ameliorated metabolic perturbations in Tg mouse hippocampus. The mechanism of this pre-emptive activity may occur via modulation of metabolic pathways dependent on Aβ interaction or independent of Aβ interaction.
  9. Tocotrienol-Rich Fraction Modulates Amyloid Pathology and Improves Cognitive Function in AβPP/PS1 Mice
    Ibrahim NF, Yanagisawa D, Durani LW, Hamezah HS, Damanhuri HA, Wan Ngah WZ, et al.
    J Alzheimers Dis, 2017;55(2):597-612.
    PMID: 27716672
    Alzheimer's disease (AD) is the most common cause of dementia. The cardinal neuropathological characteristic of AD is the accumulation of amyloid-β (Aβ) into extracellular plaques that ultimately disrupt neuronal function and lead to neurodegeneration. One possible therapeutic strategy therefore is to prevent Aβ aggregation. Previous studies have suggested that vitamin E analogs slow AD progression in humans. In the present study, we investigated the effects of the tocotrienol-rich fraction (TRF), a mixture of vitamin E analogs from palm oil, on amyloid pathology in vitro and in vivo. TRF treatment dose-dependently inhibited the formation of Aβ fibrils and Aβ oligomers in vitro. Moreover, daily TRF supplementation to AβPPswe/PS1dE9 double transgenic mice for 10 months attenuated Aβ immunoreactive depositions and thioflavin-S-positive fibrillar type plaques in the brain, and eventually improved cognitive function in the novel object recognition test compared with control AβPPswe/PS1dE9 mice. The present result indicates that TRF reduced amyloid pathology and improved cognitive functions, and suggests that TRF is a potential therapeutic agent for AD.
  10. Fulltext Tocotrienol-Rich Fraction Ameliorates Antioxidant Defense Mechanisms and Improves Replicative Senescence-Associated Oxidative Stress in Human Myoblasts
    Khor SC, Wan Ngah WZ, Mohd Yusof YA, Abdul Karim N, Makpol S
    Oxid Med Cell Longev, 2017;2017:3868305.
    PMID: 28243354 DOI: 10.1155/2017/3868305
    During aging, oxidative stress affects the normal function of satellite cells, with consequent regeneration defects that lead to sarcopenia. This study aimed to evaluate tocotrienol-rich fraction (TRF) modulation in reestablishing the oxidative status of myoblasts during replicative senescence and to compare the effects of TRF with other antioxidants (α-tocopherol (ATF) and N-acetyl-cysteine (NAC)). Primary human myoblasts were cultured to young, presenescent, and senescent phases. The cells were treated with antioxidants for 24 h, followed by the assessment of free radical generation, lipid peroxidation, antioxidant enzyme mRNA expression and activities, and the ratio of reduced to oxidized glutathione. Our data showed that replicative senescence increased reactive oxygen species (ROS) generation and lipid peroxidation in myoblasts. Treatment with TRF significantly diminished ROS production and decreased lipid peroxidation in senescent myoblasts. Moreover, the gene expression of superoxide dismutase (SOD2), catalase (CAT), and glutathione peroxidase (GPX1) was modulated by TRF treatment, with increased activity of superoxide dismutase and catalase and reduced glutathione peroxidase in senescent myoblasts. In comparison to ATF and NAC, TRF was more efficient in heightening the antioxidant capacity and reducing free radical insults. These results suggested that TRF is able to ameliorate antioxidant defense mechanisms and improves replicative senescence-associated oxidative stress in myoblasts.
  11. Fulltext Tocotrienol rich fraction supplementation improved lipid profile and oxidative status in healthy older adults: A randomized controlled study
    Chin SF, Ibahim J, Makpol S, Abdul Hamid NA, Abdul Latiff A, Zakaria Z, et al.
    Nutr Metab (Lond), 2011;8(1):42.
    PMID: 21702918 DOI: 10.1186/1743-7075-8-42
    Vitamin E supplements containing tocotrienols are now being recommended for optimum health but its effects are scarcely known. The objective was to determine the effects of Tocotrienol Rich Fraction (TRF) supplementation on lipid profile and oxidative status in healthy older individuals at a dose of 160 mg/day for 6 months.
  12. Fulltext Tocotrienol Rich Fraction Supplementation Modulate Brain Hippocampal Gene Expression in APPswe/PS1dE9 Alzheimer's Disease Mouse Model
    Wan Nasri WN, Makpol S, Mazlan M, Tooyama I, Wan Ngah WZ, Damanhuri HA
    J Alzheimers Dis, 2019;70(s1):S239-S254.
    PMID: 30507571 DOI: 10.3233/JAD-180496
    Alzheimer's disease (AD) is a progressive neurodegenerative disorder characterized by loss of memory and other cognitive abilities. AD is associated with aggregation of amyloid-β (Aβ) deposited in the hippocampal brain region. Our previous work has shown that tocotrienol rich fraction (TRF) supplementation was able to attenuate the blood oxidative status, improve behavior, and reduce fibrillary-type Aβ deposition in the hippocampus of an AD mouse model. In the present study, we investigate the effect of 6 months of TRF supplementation on transcriptome profile in the hippocampus of APPswe/PS1dE9 double transgenic mice. TRF supplementation can alleviate AD conditions by modulating several important genes in AD. Moreover, TRF supplementation attenuated the affected biological process and pathways that were upregulated in the AD mouse model. Our findings indicate that TRF supplementation can modulate hippocampal gene expression as well as biological processes that can potentially delay the progression of AD.
  13. The effects of age, physical activity level, and body anthropometry on calcaneal speed of sound value in men
    Chin KY, Soelaiman IN, Mohamed IN, Ibrahim S, Wan Ngah WZ
    Arch Osteoporos, 2012;7:135-45.
    PMID: 23225291 DOI: 10.1007/s11657-012-0091-2
    The influences of age, physical activity, and body anthropometry on calcaneal speed of sound are different among young adults, middle-aged, and elderly men.
  14. Fulltext The effects of acacia honey on in vitro corneal abrasion wound healing model
    Ker-Woon C, Abd Ghafar N, Hui CK, Mohd Yusof YA, Wan Ngah WZ
    BMC Cell Biol., 2015;16:2.
    PMID: 25887200 DOI: 10.1186/s12860-015-0053-9
    Acacia honey (AH) has been proven to improve skin wound healing, but its therapeutic effects on corneal epithelium has not been elucidated to date. This study aimed to investigate the effects of AH on cultured corneal epithelial cells (CEC) on in vitro corneal abrasion wound healing model. Six New Zealand white rabbits' CEC were isolated and cultured until passage 1. Circular wound area was created onto a confluent monolayer CEC using a corneal trephine which mimicked corneal abrasion and treated with 0.025% AH supplemented in basal medium (BM) and complete cornea medium (CCM). Wound healing was measured as the percentage of wound closure by the migration of CEC on day 0, day 3 and day 6, post wound creation. The morphological changes of CEC were assessed via phase contrast microscopy. Gene and protein expressions of cytokeratin (CK3), fibronectin and cluster of differentiation 44 (CD44) in AH treated groups and control groups were determined by real-time PCR and immunocytochemistry, respectively.
  15. Fulltext The association between bone health indicated by calcaneal quantitative ultrasound and metabolic syndrome in Malaysian men
    Chin KY, Ima-Nirwana S, Mohamed IN, Ahmad F, Mohd Ramli ES, Aminuddin A, et al.
    J Diabetes Metab Disord, 2015;14:9.
    PMID: 25789255 DOI: 10.1186/s40200-015-0136-3
    BACKGROUND: Previous studies on the relationship between bone health and metabolic syndrome (MS) have revealed heterogeneous results. There are limited studies employing bone quantitative ultrasonometry in evaluating this relationship. This study aimed to determine the relationship between MS and bone health in a group of Malaysian middle-aged and elderly men using bone quantitative ultrasonometry.

    METHODS: This cross-sectional study recruited 309 free living Chinese and Malay men aged 40 years and above residing in Klang Valley, Malaysia. Their demographic and anthropometric data were collected. Their calcaneal speed of sound (SOS) was measured using a CM-200 bone ultrasonometer. Their blood was collected for the evaluation of lipid profile, total testosterone and sex hormone-binding globulin. The joint interim MS definition was used for the classification of subjects. Multiple linear regression analysis was used to assess the association between SOS and indicators of MS and the presence of MS, with suitable adjustment for confounders.

    RESULTS: There was no significant difference in SOS value between MS and non-MS subjects (p > 0.05). The SOS values among subjects with different MS scores did not differ significantly (p > 0.05). There were no significant associations between SOS values and indicators of MS or the presence of MS (p > 0.05).

    CONCLUSIONS: The relationship between bone health and MS is not significant in Malaysian middle-aged and elderly men. A longitudinal study should be conducted to evaluate the association between bone loss and MS to confirm this finding.

  16. Fulltext The Tocotrienol-Rich Fraction Is Superior to Tocopherol in Promoting Myogenic Differentiation in the Prevention of Replicative Senescence of Myoblasts
    Khor SC, Razak AM, Wan Ngah WZ, Mohd Yusof YA, Abdul Karim N, Makpol S
    PLoS One, 2016;11(2):e0149265.
    PMID: 26885980 DOI: 10.1371/journal.pone.0149265
    Aging results in a loss of muscle mass and strength. Myoblasts play an important role in maintaining muscle mass through regenerative processes, which are impaired during aging. Vitamin E potentially ameliorates age-related phenotypes. Hence, this study aimed to determine the effects of the tocotrienol-rich fraction (TRF) and α-tocopherol (ATF) in protecting myoblasts from replicative senescence and promoting myogenic differentiation. Primary human myoblasts were cultured into young and senescent stages and were then treated with TRF or ATF for 24 h, followed by an analysis of cell proliferation, senescence biomarkers, cellular morphology and differentiation. Our data showed that replicative senescence impaired the normal regenerative processes of myoblasts, resulting in changes in cellular morphology, cell proliferation, senescence-associated β-galactosidase (SA-β-gal) expression, myogenic differentiation and myogenic regulatory factors (MRFs) expression. Treatment with both TRF and ATF was beneficial to senescent myoblasts in reclaiming the morphology of young cells, improved cell viability and decreased SA-β-gal expression. However, only TRF treatment increased BrdU incorporation in senescent myoblasts, as well as promoted myogenic differentiation through the modulation of MRFs at the mRNA and protein levels. MYOD1 and MYOG gene expression and myogenin protein expression were modulated in the early phases of myogenic differentiation. In conclusion, the tocotrienol-rich fraction is superior to α-tocopherol in ameliorating replicative senescence-related aberration and promoting differentiation via modulation of MRFs expression, indicating vitamin E potential in modulating replicative senescence of myoblasts.
  17. Fulltext The Role of Oxidative Stress in Suicidal Behaviour Among Bipolar Patients: A Cross-Sectional Study in a Malaysian Sample
    Loo JL, Mohamad Kamal NA, Goon JA, Ahmad Damanhuri H, Tan JAC, Abdul Murad NA, et al.
    Front Psychiatry, 2021;12:698911.
    PMID: 34916966 DOI: 10.3389/fpsyt.2021.698911
    Background: Oxidative stress markers are found to be linked with depression and suicide attempts in bipolar disorder (BD), although the role of DNA damage as a marker of suicidal ideation and attempt has yet to be determined. We aim to investigate the association between DNA damage and suicidal behaviour, i.e., suicidal ideation and suicide attempt, among suicidal ideators in BD patients while accounting for clinical and psychosocial risk factors. Methods: A cross-sectional study was conducted in the Universiti Kebangsaan Malaysia Medical Centre on 62 consecutive BD patients diagnosed using the M.I.N.I. Neuropsychiatric Interview and 26 healthy control participants. Socio-demographic and clinical assessments were performed using the Columbia Suicide Severity Rating Scale (C-SSRS) for lifetime suicidal ideation and attempt, Quick Inventory of Depressive Symptomatology (QIDS) for depression severity, Clinical Global Impression for Bipolar Disorder (CGI-BD) for illness severity [both mania (CGI-Mania) and major depressive episode (CGI-MDE)], Social Readjustment Rating Scale (SRRS) for change in life events, and Barratt Impulsiveness Scale (BIS) for behavioural impulsivity. The degree of DNA damage in peripheral blood samples was determined using a standard protocol of comet assay. Results: Multivariable logistic regression revealed higher scores of CGI-MDE as the sole significant factor for lifetime suicidal ideation (OR = 1.937, 95% CI = 1.799-2.076). Although initial bivariate analysis showed a significant association between DNA damage, malondialdehyde (MDA), catalase (CAT), and suicidal behaviour, the findings were not seen in multivariable logistic regression. Bivariate subgroup analysis showed that moderate and severe DNA damage (p = 0.032 and p = 0.047, respectively) was significantly associated with lifetime suicide attempts among lifetime suicidal ideators. The study is the first to look at the connexion between DNA damage and suicidal risk in bipolar patients. It is limited by the small sample size and lack of information on illicit substance use. Conclusions: More severe DNA damage was significantly associated with lifetime suicide attempts among lifetime suicidal ideators in BD. However, the severity of depression was found to be independently associated with lifetime suicidal ideation per se rather than DNA damage in BD. Larger prospective studies are required to ascertain the potential of DNA damage as a biomarker for the transition from suicidal ideation to a suicide attempt.
  18. Targeting genes in insulin-associated signalling pathway, DNA damage, cell proliferation and cell differentiation pathways by tocotrienol-rich fraction in preventing cellular senescence of human diploid fibroblasts
    Durani LW, Jaafar F, Tan JK, Tajul Arifin K, Mohd Yusof YA, Wan Ngah WZ, et al.
    Clin Ter, 2016;166(6):e365-73.
    PMID: 26794818 DOI: 10.7417/T.2015.1902
    Tocotrienols have been known for their antioxidant properties besides their roles in cellular signalling, gene expression, immune response and apoptosis. This study aimed to determine the molecular mechanism of tocotrienol-rich fraction (TRF) in preventing cellular senescence of human diploid fibroblasts (HDFs) by targeting the genes in senescence-associated signalling pathways.
  19. Suppression of colorectal cancer cell growth by combined treatment of 6-gingerol and γ-tocotrienol via alteration of multiple signalling pathways
    Yusof KM, Makpol S, Fen LS, Jamal R, Wan Ngah WZ
    J Nat Med, 2019 Sep;73(4):745-760.
    PMID: 31177355 DOI: 10.1007/s11418-019-01323-6
    Our previous study reported that combined treatment of γ-tocotrienol with 6-gingerol showed promising anticancer effects by synergistically inhibiting proliferation of human colorectal cancer cell lines. This study aimed to identify and elucidate molecular mechanisms involved in the suppression of SW837 colorectal cancer cells modulated by combined treatment of γ-tocotrienol and 6-gingerol. Total RNA from both untreated and treated cells was prepared for transcriptome analysis using RNA sequencing techniques. We performed high-throughput sequencing at approximately 30-60 million coverage on both untreated and 6G + γT3-treated cells. The results showed that cancer-specific differential gene expression occurred and functional enrichment pathway analysis suggested that more than one pathway was modulated in 6G + γT3-treated cells. Combined treatment with 6G + γT3 augmented its chemotherapeutic effect by interfering with the cell cycle process, downregulating the Wnt signalling pathway and inducing apoptosis mainly through caspase-independent programmed cell death through mitochondrial dysfunction, activation of ER-UPR, disruption of DNA repair mechanisms and inactivation of the cell cycle process through the downregulation of main genes in proliferation such as FOXM1 and its downstream genes. The combined treatment exerted its cytotoxic effect through upregulation of genes in stress response activation and cytostatic effects demonstrated by downregulation of main regulator genes in the cell cycle. Selected genes involved in particular pathways including ATF6, DDIT3, GADD34, FOXM1, CDK1 and p21 displayed concordant patterns of gene expression between RNA sequencing and RT-qPCR. This study provides new insights into combined treatment with bioactive compounds not only in terms of its pleiotropic effects that enhance multiple pathways but also specific target genes that could be exploited for therapeutic purposes, especially in suppressing cancer cell growth.
  20. Supplementation with tocotrienol-rich fraction alters the plasma levels of Apolipoprotein A-I precursor, Apolipoprotein E precursor, and C-reactive protein precursor from young and old individuals
    Heng EC, Karsani SA, Abdul Rahman M, Abdul Hamid NA, Hamid Z, Wan Ngah WZ
    Eur J Nutr, 2013 Oct;52(7):1811-20.
    PMID: 23287846 DOI: 10.1007/s00394-012-0485-3
    PURPOSE: Tocotrienol possess beneficial effects not exhibited by tocopherol. In vitro studies using animal models have suggested that these effects are caused via modulation of gene and protein expression. However, human supplementation studies using tocotrienol-rich isomers are limited. This study aims to identify plasma proteins that changed in expression following tocotrienol-rich fraction (TRF) supplementation within two different age groups.

    METHODS: Subjects were divided into two age groups-32 ± 2 (young) and 52 ± 2 (old) years old. Four subjects from each group were assigned with TRF (78% tocotrienol and 22% tocopherol, 150 mg/day) or placebo capsules for 6 months. Fasting plasma were obtained at 0, 3, and 6 months. Plasma tocopherol and tocotrienol levels were determined. Plasma proteome was resolved by 2DE, and differentially expressed proteins identified by MS. The expressions of three proteins were validated by Western blotting.

    RESULTS: Six months of TRF supplementation significantly increased plasma levels of tocopherols and tocotrienols. Proteins identified as being differentially expressed were related to cholesterol homeostasis, acute-phase response, protease inhibitor, and immune response. The expressions of Apolipoprotein A-I precursor, Apolipoprotein E precursor, and C-reactive protein precursor were validated. The old groups showed more proteins changing in expression.

    CONCLUSIONS: TRF appears to not only affect plasma levels of tocopherols and tocotrienols, but also the levels of plasma proteins. The identity of these proteins may provide insights into how TRF exerts its beneficial effects. They may also be potentially developed into biomarkers for the study of the effects and effectiveness of TRF supplementation.

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