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  1. Mehat MZ, Shuid AN, Mohamed N, Muhammad N, Soelaiman IN
    J. Bone Miner. Metab., 2010 Sep;28(5):503-9.
    PMID: 20145960 DOI: 10.1007/s00774-010-0159-2
    Bone is a specialized connective tissue that functions as the load-bearing structure of the body. Free radicals may affect bone remodeling by regulating osteoclast activity in either the physiological or pathological condition. Vitamin E, a lipid-soluble antioxidant, has been demonstrated to offer protection against osteoporosis and to improve the bone material and structure of animal models. The aim of this study was to observe and compare the effects of alpha-tocopherol (alpha-tocopherol), delta-tocotrienol (delta-tocotrienol), and gamma-tocotrienol (gamma-tocotrienol) on the static and dynamic bone histomorphometric parameters in normal male rats. Thirty-two normal Sprague-Dawley male rats aged 3 months and weighing 200-250 g were randomly divided into four groups. The control group was supplemented with oral gavages of olive oil (vehicle), whereas the alpha-tocopherol, delta-tocotrienol, and gamma-tocotrienol groups were given oral gavages of 60 mg/kg alpha-tocopherol, delta-tocotrienol, and gamma-tocotrienol, respectively. The rats were injected twice with calcein to fluorochrome-label the bones. After 4 months of treatment, the rats were killed, and the left femurs were dissected out and prepared for bone histomorphometry. Both the static and dynamic parameters of the vitamin E-treated groups were better than those of the normal control group. Among the vitamin E-treated groups, the tocotrienol groups showed better histomorphometry results compared to the α-tocopherol group, with the γ-tocotrienol group demonstrating the best effects on both sets of parameters. We concluded that vitamin E can promote bone formation in normal rats, with gamma-tocotrienol being the most potent form of vitamin E.
  2. Muhammad SA, Nordin N, Mehat MZ, Fakurazi S
    Cell Tissue Res, 2019 Feb;375(2):329-344.
    PMID: 30084022 DOI: 10.1007/s00441-018-2884-0
    Articular cartilage defect remains the most challenging joint disease due to limited intrinsic healing capacity of the cartilage that most often progresses to osteoarthritis. In recent years, stem cell therapy has evolved as therapeutic strategies for articular cartilage regeneration. However, a number of studies have shown that therapeutic efficacy of stem cell transplantation is attributed to multiple secreted factors that modulate the surrounding milieu to evoke reparative processes. This systematic review and meta-analysis aim to evaluate and compare the therapeutic efficacy of stem cell and secretome in articular cartilage regeneration in animal models. We systematically searched the PubMed, CINAHL, Cochrane Library, Ovid Medline and Scopus databases until August 2017 using search terms related to stem cells, cartilage regeneration and animals. A random effect meta-analysis of the included studies was performed to assess the treatment effects on new cartilage formation on an absolute score of 0-100% scale. Subgroup analyses were also performed by sorting studies independently based on similar characteristics. The pooled analysis of 59 studies that utilized stem cells significantly improved new cartilage formation by 25.99% as compared with control. Similarly, the secretome also significantly increased cartilage regeneration by 26.08% in comparison to the control. Subgroup analyses revealed no significant difference in the effect of stem cells in new cartilage formation. However, there was a significant decline in the effect of stem cells in articular cartilage regeneration during long-term follow-up, suggesting that the duration of follow-up is a predictor of new cartilage formation. Secretome has shown a similar effect to stem cells in new cartilage formation. The risk of bias assessment showed poor reporting for most studies thereby limiting the actual risk of bias assessment. The present study suggests that both stem cells and secretome interventions improve cartilage regeneration in animal trials. Graphical abstract ᅟ.
  3. Zolkiffly SZI, Stanslas J, Abdul Hamid H, Mehat MZ
    J Ethnopharmacol, 2021 Oct 28;279:114309.
    PMID: 34119609 DOI: 10.1016/j.jep.2021.114309
    ETHNOPHARMACOLOGICAL RELEVANCE: Ficus deltoidea Jack (FD) is widely consumed in traditional medicine as a treatment for various diseases in Malaysia. Each part of the plant such as its leave, stem, fruit and root are used traditionally to treat different types of diseases. Vitexin and isovitexin are bioactive compounds abundantly found in the leaves of FD that possessed many pharmacological properties including neuroprotection. Nonetheless, its effects on key events in neuroinflammation are unknown.

    AIM OF THE STUDY: To determine the inhibitory properties of FD aqueous extract on pro-inflammatory mediators involved in lipopolysaccharide (LPS)-induced microglial cells.

    METHODS: Vitexin and isovitexin in the extract were quantified via high performance liquid chromatography (HPLC). The extract was evaluated for its cytotoxicity activity via 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Pre-treatment with the extract on LPS-induced microglial cells was done to determine its antioxidant and anti-neuroinflammatory properties by measuring the level of reactive oxygen species (ROS), nitric oxide (NO), tumour necrosis factor alpha (TNF-α), interleukin-1β (IL-1β) and interleukin-6 (IL-6) via 2'-7'-dichlorofluorescin diacetate (DCFDA) assay, Griess assay and Western blot respectively.

    RESULTS: The extract at all tested concentrations (0.1 μg/mL, 1 μg/mL, 10 μg/mL, 100 μg/mL) were not cytotoxic as the percentage viability of microglial cells were all above ~80%. At the highest concentration (100 μg/mL), the extract significantly reduced the formation of ROS, NO, TNF-α, IL-1β and IL-6 in microglial cells induced by LPS.

    CONCLUSION: The extract showed neuroprotective effects by attenuating the levels of pro-inflammatory and cytotoxic factors in LPS-induced microglial cells, possibly by mediating the nuclear factor-kappa B (NF-κB) signalling pathway.

  4. Muhammad SA, Nordin N, Hussin P, Mehat MZ, Abu Kasim NH, Fakurazi S
    PLoS One, 2020;15(9):e0238449.
    PMID: 32886713 DOI: 10.1371/journal.pone.0238449
    Treatment of osteoarthritis (OA) is still a major clinical challenge due to the limited inherent healing capacity of cartilage. Recent studies utilising stem cells suggest that the therapeutic benefits of these cells are mediated through the paracrine mechanism of bioactive molecules. The present study evaluates the regenerative effect of stem cells from human exfoliated deciduous teeth (SHED) conditioned medium (CM) on OA chondrocytes. The CM was collected after the SHED were cultured in serum-free medium (SFM) for 48 or 72 h and the cells were characterised by the expression of MSC and pluripotency markers. Chondrocytes were stimulated with interleukin-1β and treated with the CM. Subsequently, the expression of aggrecan, collagen type 2 (COL 2), matrix metalloproteinase-13 (MMP-13), nuclear factor-kB (NF-kB) and the level of inflammatory and anti-inflammatory markers were evaluated. SHED expressed mesenchymal stromal cell surface proteins but were negative for haematopoietic markers. SHED also showed protein expression of NANOG, OCT4 and SOX2 with differential subcellular localisation. Treatment of OA chondrocytes with CM enhanced anti-inflammation compared to control cells treated with SFM. Furthermore, the expression of MMP-13 and NF-kB was significantly downregulated in stimulated chondrocytes incubated in CM. The study also revealed that CM increased the expression of aggrecan and COL 2 in OA chondrocytes compared to SFM control. Both CM regenerate extracellular matrix proteins and mitigate increased MMP-13 expression through inhibition of NF-kB in OA chondrocytes due to the presence of bioactive molecules. The study underscores the potential of CM for OA treatment.
  5. Muhammad SA, Nordin N, Hussin P, Mehat MZ, Tan SW, Fakurazi S
    Cartilage, 2021 12;13(2_suppl):872S-884S.
    PMID: 31540551 DOI: 10.1177/1947603519876333
    OBJECTIVE: Cartilage tissue engineering has evolved as one of the therapeutic strategies for cartilage defect, which relies on a large number of viable chondrocytes. Because of limited availability of cartilage and low chondrocytes yield from cartilage, the need for an improve isolation protocol for maximum yield of viable cells is a key to achieving successful clinical constructs. This study optimizes and compares different protocols for isolation of chondrocytes from cartilage.

    DESIGN: We employed enzymatic digestion of cartilage using collagenase II and trypsin. The chondrocytes yield, growth kinetics, aggrecan, and collagen type 2 (COL2) expression were evaluated. Collagen type 1 (COL1) mRNA expression was assessed to monitor the possibility of chondrocytes dedifferentiation.

    RESULTS: Chondrocyte yield per gram of cartilage was significantly higher (P < 0.05) using collagenase II in Hank's balanced salt solution (HBSS) compared with 0.25% trypsin. The number of chondrocyte yield per gram was higher in cartilage digested with collagenase in HBSS compared with Dulbecco's modified Eagle medium/F12; however, the difference was not statistically significant. Chondrocytes seeded at lower densities had shorter population doubling time compared to those seeded at higher density. Protein and gene expression of chondrocyte phenotype indicates the expression of aggrecan and COL2. The expression of COL1 was significantly increased (P < 0.05) in passage 3 compared with primary chondrocytes. The mRNA expression of chondrocyte phenotype was similar in primary and passaged one cells.

    CONCLUSIONS: Collagenase in HBSS yield the highest number of viable chondrocytes and the isolated cells expressed chondrocyte phenotype. This protocol can be employed to generate large number of viable chondrocytes, particularly with limited cartilage biopsies.

  6. Yahaya MAF, Zolkiffly SZI, Moklas MAM, Hamid HA, Stanslas J, Zainol M, et al.
    J Immunol Res, 2020;2020:9469210.
    PMID: 32258178 DOI: 10.1155/2020/9469210
    Alzheimer's disease (AD) has been clinically characterized by a progressive degeneration of neurons which resulted in a gradual and irreversible cognitive impairment. The accumulation of Aβ and τ proteins in the brain contribute to the severity of the disease. Recently, vitexin compound has been the talk amongst researchers due to its pharmacological properties as anti-inflammation and anti-AD. However, the epigenetic mechanism of the compound in regulating the neuroinflammation activity is yet to be fully elucidated. Hence, this review discusses the potential of vitexin compound to have the pharmacoepigenetic property in regulating the neuroinflammation activity in relation to AD. It is with hope that the review would unveil the potential of vitexin as the candidate in treating AD.
  7. Yahaya MAF, Bakar ARA, Stanslas J, Nordin N, Zainol M, Mehat MZ
    BMC Biotechnol, 2021 06 05;21(1):38.
    PMID: 34090414 DOI: 10.1186/s12896-021-00697-4
    BACKGROUND: Neuroinflammation has been identified to be the key player in most neurodegenerative diseases. If neuroinflammation is left to be unresolved, chronic neuroinflammation will be establish. Such situation is due to the overly-activated microglia which have the tendency to secrete an abundance amount of pro-inflammatory cytokines into the neuron microenvironment. The abundance of pro-inflammatory cytokines will later cause toxic and death to neurons. Toll-like receptor 4 (TLR4)/MD-2 complex found on the cell surface of microglia is responsible for the attachment of LPS and activation of nuclear factor-κB (NF-κB) downstream signalling pathway. Albeit vitexin has been shown to possess anti-inflammatory property, however, little is known on its ability to bind at the binding site of TLR4/MD-2 complex of microglia as well as to be an antagonist for LPS.

    RESULTS: The present study reveals that both vitexin and donepezil are able to bind at the close proximity of LPS binding site located at the TLR4/MD-2 complex with the binding energy of - 4.35 and - 9.14 kcal/mol, respectively. During molecular dynamic simulations, both vitexin and donepezil formed stable complex with TLR4/MD-2 throughout the 100 ns time length with the root mean square deviation (RMSD) values of 2.5 Å and 4.0 Å, respectively. The root mean square fluctuation (RMSF) reveals that both compounds are stable. Interestingly, the radius of gyration (rGyr) for donepezil shows notable fluctuations when compare with vitexin. The MM-GBSA results showed that vitexin has higher binding energy in comparison with donepezil.

    CONCLUSIONS: Taken together, the findings suggest that vitexin is able to bind at the binding site of TLR4/MD-2 complex with more stability than donepezil throughout the course of 100 ns simulation. Hence, vitexin has the potential to be an antagonist candidate for LPS.

  8. Romli MH, Cheema MS, Mehat MZ, Md Hashim NF, Abdul Hamid H
    BMJ Open, 2020 Nov 23;10(11):e041153.
    PMID: 33234650 DOI: 10.1136/bmjopen-2020-041153
    INTRODUCTION: Rapid technology development due to the introduction of Industrial Revolution 4.0 and Internet of Things has created a demand and gradual transition from traditional teaching and learning to technology-based learning in higher education, including healthcare education. The COVID-19 pandemic has accelerated this process, with educators now required to quickly adapt to and adopt such changes. The abundance of available systematic reviews has made the effectiveness of such approaches ambiguous especially in healthcare education. Therefore, a protocol of the overview of systematic reviews (OoSR) is planned to extrapolate the effectiveness of technology-based learning in undergraduate healthcare education.

    METHODS AND ANALYSIS: Scopus, CINAHL, Academic Search Complete, Cochrane Library, MEDLINE and Psychology and Behavioral Sciences Collection databases were selected. Screening was conducted independently by at least two authors and the decision for inclusion was done through discussion or involvement of an arbiter against a predetermined criteria. Included articles will be evaluated for quality using A MeaSurement Tool to Assess systematic Reviews and Risk of Bias in Systematic Review tools, while primary systematic review articles will be cross-checked and reported for any overlapping using the 'corrected covered area' method. Only narrative synthesis will be employed according to the predefined themes into two major dimensions-theory and knowledge generation (focusing on cognitive taxonomy due to its ability to be generalised across disciplines), and clinical-based competence (focusing on psychomotor and affective taxonomies due to discipline-specific influence). The type of technology used will be identified and extracted.

    ETHICS AND DISSEMINATION: The OoSR involves analysis of secondary data from published literature, thus ethical approval is not required. The findings will provide a valuable insight for policymakers, stakeholders, and researchers in terms of technology-based learning implementation and gaps identification. The findings will be published in several reports due to the extensiveness of the topic and will be disseminated through peer-reviewed publications and conferences.

    PROSPERO REGISTRATION NUMBER: CRD4202017974.

  9. Hambali A, Kumar J, Hashim NFM, Maniam S, Mehat MZ, Cheema MS, et al.
    Front Physiol, 2021;12:712317.
    PMID: 34721056 DOI: 10.3389/fphys.2021.712317
    Alzheimer's disease (AD) is a neurodegenerative disorder that is characterised by the presence of extracellular beta-amyloid fibrillary plaques and intraneuronal neurofibrillary tau tangles in the brain. Recurring failures of drug candidates targeting these pathways have prompted research in AD multifactorial pathogenesis, including the role of neuroinflammation. Triggered by various factors, such as hypoxia, neuroinflammation is strongly linked to AD susceptibility and/or progression to dementia. Chronic hypoxia induces neuroinflammation by activating microglia, the resident immune cells in the brain, along with an increased in reactive oxygen species and pro-inflammatory cytokines, features that are common to many degenerative central nervous system (CNS) disorders. Hence, interests are emerging on therapeutic agents and plant derivatives for AD that target the hypoxia-neuroinflammation pathway. Centella asiatica is one of the natural products reported to show neuroprotective effects in various models of CNS diseases. Here, we review the complex hypoxia-induced neuroinflammation in the pathogenesis of AD and the potential application of Centella asiatica as a therapeutic agent in AD or dementia.
  10. Che Mohd Nassir CMN, Damodaran T, Ismail NI, Hashim S, Jaffer U, Hamid HA, et al.
    Life (Basel), 2023 Jan 12;13(1).
    PMID: 36676165 DOI: 10.3390/life13010216
    In this narrative review, we present the evidence on nucleotide-binding and oligomerization (NOD) domain-like receptor (NLR) family pyrin domain (PYD)-containing 3 (NLRP3) inflammasome activation for its putative roles in the elusive pathomechanism of aging-related cerebral small vessel disease (CSVD). Although NLRP3 inflammasome-interleukin (IL)-1β has been implicated in the pathophysiology of coronary artery disease, its roles in cerebral arteriothrombotic micro-circulation disease such as CSVD remains unexplored. Here, we elaborate on the current manifestations of CSVD and its' complex pathogenesis and relate the array of activators and aberrant activation involving NLRP3 inflammasome with this condition. These neuroinflammatory insights would expand on our current understanding of CSVD clinical (and subclinical) heterogenous manifestations whilst highlighting plausible NLRP3-linked therapeutic targets.
  11. Hambali A, Jusril NA, Md Hashim NF, Abd Manan N, Adam SK, Mehat MZ, et al.
    J Alzheimers Dis, 2024 Jan 16.
    PMID: 38250772 DOI: 10.3233/JAD-230875
    BACKGROUND: Neuroinflammation and oxidative stress can aggravate the progression of Alzheimer's disease (AD). Centella asiatica has been traditionally consumed for memory and cognition. The triterpenes (asiaticoside, madecassoside, asiatic acid, madecassic acid) have been standardized in the ethanolic extract of Centella asiatica (SECA). The bioactivity of the triterpenes in different solvent polarities of SECA is still unknown.

    OBJECTIVE: In this study, the antioxidative and anti-neuroinflammatory effects of SECA and its fractions were explored on lipopolysaccharides (LPS)-induced microglial cells.

    METHODS: HPLC measured the four triterpenes in SECA and its fractions. SECA and its fractions were tested for cytotoxicity on microglial cells using MTT assay. NO, pro-inflammatory cytokines (TNF-α, IL-6, IL-1β), ROS, and MDA (lipid peroxidation) produced by LPS-induced microglial cells were measured by colorimetric assays and ELISA. Nrf2 and HO-1 protein expressions were measured using western blotting.

    RESULTS: The SECA and its fractions were non-toxic to BV2 microglial cells at tested concentrations. The levels of NO, TNF-α, IL-6, ROS, and lipid peroxidation in LPS-induced BV2 microglial cells were significantly reduced (p 

  12. Wahab MSA, Zaini MH, Ali AA, Sahudin S, Mehat MZ, Hamid HA, et al.
    BMC Complement Med Ther, 2021 Apr 01;21(1):110.
    PMID: 33794868 DOI: 10.1186/s12906-021-03287-1
    BACKGROUND: The use of herbal and dietary supplement (HDS) in health and disease management has gained global attention. HDS are generally accepted by the public and are associated with positive health behaviours. However, several reports have been documented with regards to their potential adverse effects and interaction with conventional medicines. Limited data is currently available on the use of HDS among elderly population in Malaysia. This present study aims to investigate the prevalence of and pattern of HDS use among a sample of community-dwelling elderly in a suburban town in Malaysia.

    METHODS: A cross-sectional survey was conducted between March and May 2019 among the elderly aged ≥60 years old. The participants with the following criteria were included in the study: aged ≥60 years, residing in Puncak Alam and able to understand Malay or English language. Data were collected using a pre-validated questionnaire. All statistical analysis was conducted using IBM SPSS ver. 23.

    RESULTS: Overall, 336 out of 400 elderly responded to the survey, achieving a response rate of 84%. This study observed that almost 50% of the respondents were using at least one type of HDS in the past one month of the survey. Among HDS non-users, most of them preferred to use modern medicines (62.6%, 114/182). Among the HDS users, 75.3% (116/154) were using at least one type of modern medicine (prescription or over-the-counter medicine). Multivariate analysis showed that having good to excellent perceived health (adjusted OR = 2.666, 95% CI = 1.592-4.464), having felt sick at least once in the past one month (adjusted OR = 2.500, 95% CI = 1.426-4.383), and lower body mass index (adjusted OR = 0.937, 95% CI = 0.887-0.990) were associated with HDS use. It was noted that only a small percentage of HDS users (16.2%, 25/154) had informed healthcare providers on their HDS use.

    CONCLUSION: The use of HDS is common among the elderly sampled. Hence, healthcare providers should be more vigilant in seeking information of HDS use for disease management in their elderly patients. Campaigns that provide accurate information regarding the appropriate use of HDS among the elderly are pertinent to prevent misinformation of the products.

  13. Manoharan SD, Abdul Hamid H, Md Hashim NF, Cheema MS, Chiroma SM, Mustapha M, et al.
    Brain Res, 2024 Apr 15;1829:148793.
    PMID: 38309553 DOI: 10.1016/j.brainres.2024.148793
    Alzheimer's disease (AD) is a progressive neurological disorder that impairs memory and cognitive abilities, primarily in the elderly. The burden of AD extends beyond patients, impacting families and caregivers due to the patients' reliance on assistance for daily tasks. The main features of the pathogenesis of AD are beta-amyloid plaques and neurofibrillary tangles (NFTs), that strongly correlate with oxidative stress and inflammation. NFTs result from misfolded and hyperphosphorylated tau proteins. Various studies have focused on tau phosphorylation, indicating protein phosphatase 2A (PP2A) as the primary tau phosphatase and glycogen synthase kinase-3 beta (GSK-3β) as the leading tau kinase. Experimental evidence suggests that inhibition of PP2A and increased GSK-3β activity contribute to neuroinflammation, oxidative stress, and cognitive impairment. Hence, targeting PP2A and GSK-3β with pharmacological approaches shows promise in treating AD. The use of natural compounds in the drug development for AD have been extensively studied for their antioxidant, anti-inflammatory, anti-cholinesterase, and neuroprotective properties, demonstrating therapeutic advantages in neurological diseases. Alongside the development of PP2A activator and GSK-3β inhibitor drugs, natural compounds are likely to have neuroprotective effects by increasing PP2A activity and decreasing GSK-3β levels. Therefore, based on the preclinical and clinical studies, the potential of PP2A and GSK-3β as therapeutic targets of natural compounds are highlighted in this review.
  14. Iman IN, Yusof NAM, Talib UN, Ahmad NAZ, Norazit A, Kumar J, et al.
    Front Behav Neurosci, 2021;15:683780.
    PMID: 34149373 DOI: 10.3389/fnbeh.2021.683780
    The use of animal models for substance use disorder (SUD) has made an important contribution in the investigation of the behavioral and molecular mechanisms underlying substance abuse and addiction. Here, we review a novel and comprehensive behavioral platform to characterize addiction-like traits in rodents using a fully automated learning system, the IntelliCage. This system simultaneously captures the basic behavioral navigation, reward preference, and aversion, as well as the multi-dimensional complex behaviors and cognitive functions of group-housed rodents. It can reliably capture and track locomotor and cognitive pattern alterations associated with the development of substance addiction. Thus, the IntelliCage learning system offers a potentially efficient, flexible, and sensitive tool for the high-throughput screening of the rodent SUD model.
  15. Iman IN, Ahmad NAZ, Mohd Yusof NA, Talib UN, Norazit A, Kumar J, et al.
    Front Pharmacol, 2021;12:708055.
    PMID: 34603022 DOI: 10.3389/fphar.2021.708055
    Kratom is a widely abused plant-based drug preparation with a global interest in recent years, well beyond its native grounds in Southeast Asia. Mitragynine, its major psychoactive constituent is known to exhibit opioid-like behavioral effects with resultant neuroplasticity in the brain reward system. Its chronic administration is associated with cognitive impairments in animal studies. However, the underlying molecular mechanism for such a deficit remains elusive. In this study, the involvement of cannabinoid type-1 (CB1) receptors in cognitive deficits after chronic mitragynine exposures was investigated for 28 days (with incremental dose sensitization from 1 to 25 mg/kg) in adult male Swiss albino mice using the IntelliCage® system. Chronic high-dose mitragynine exposure (5-25 mg/kg, intraperitoneal [i.p.]), but not low-dose exposure (1-4 mg/kg, i.p.), induced hyperlocomotion, potentiated the preference for sucrose reward, increased resistance to punishment, and impaired place learning and its reversal. Comparable deficits were also observed after chronic treatments with Δ-9-tetrahydrocannabinol (THC, 2 mg/kg, i.p.) or morphine (5 mg/kg, subcutaneous). Mitragynine-, morphine-, and THC-induced learning and memory deficits were reversed by co-treatment with the CB1 receptor antagonist, NIDA-41020 (10 mg/kg, i.p.). A significant upregulation of CB1 receptor expression was found in the hippocampal CA1 region and ventral tegmental area after chronic high-dose mitragynine and morphine, whereas a downregulation was observed after chronic THC. In conclusion, the present study suggests a plausible role of the CB1 receptor in mediating the dose-dependent cognitive deficits after chronic high-dose mitragynine exposure. This also highlights the potential of CB1 receptor antagonism in ameliorating the cognitive deficits associated with long-term kratom/mitragynine consumption in humans.
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