Displaying publications 1 - 20 of 67 in total

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  1. Nordin F, Ahmad RNR, Farzaneh F
    Virus Res, 2017 05 02;235:106-114.
    PMID: 28408207 DOI: 10.1016/j.virusres.2017.04.007
    Induced pluripotent stem cells (iPSC) are somatic cells reprogrammed to pluripotency by forced expression of pluripotency factors. These cells are shown to have the same pluripotent potential as embryonic stem cells (ESC) and considered as an alternative to the much controversial usage of ESC which involved human embryos. However, the traditional method in reprogramming cells into iPSC using genome-integrating retro- or lenti- viruses remains an obstacle for its application in clinical setting. Although numerous studies have been conducted for a safer DNA-based reprogramming, reprogramming of iPSC by genetic modifications may raise the possibility of malignant transformation and has been a major limitation for its usage in clinical applications. Therefore, there is a need for an alternative method to reprogram the cells without the use of gene editing and a much safer way to deliver transcription factors to induce pluripotency on target cells. Using protein transduction approach, a number of studies have demonstrated the generation of human iPSCs from human fibroblasts and mouse embryonic fibroblasts by direct delivery of reprogramming proteins. In this review, the definition and mechanism of HIV-TAT protein (a type of protein transduction domain) in delivering recombinant proteins, including the potential of protein-based delivery to induce iPSC were further discussed.
    Matched MeSH terms: Induced Pluripotent Stem Cells/physiology*
  2. Al Abbar A, Nordin N, Ghazalli N, Abdullah S
    Tissue Cell, 2018 Dec;55:13-24.
    PMID: 30503056 DOI: 10.1016/j.tice.2018.09.004
    Induced pluripotent stem cells (iPSCs) have great potentials for regenerative medicine. However, serious concerns such as the use of the viral-mediated reprogramming strategies and exposure of iPSCs to animal products from feeder cells and serum-containing medium have restricted the application of iPSCs in the clinics. Therefore, the generation of iPSCs with minimal viral integrations and in non-animal sourced and serum-free medium is necessary. In this report, a polycistronic lentiviral vector carrying Yamanaka's factors was used to reprogram mouse fibroblasts into iPSCs in feeder- and xeno-free culture environment. The generated iPSCs exhibited morphology and self-renewal properties of embryonic stem cells (ESCs), expression of specific pluripotent markers, and potentials to differentiate into the three-major distinct specialized germ layers in vitro. The iPSCs were also shown to have the potential to differentiate into neural precursor and neurons in culture, with greater than 95% expression of nestin, Pax6 and βIII-tubulin. This body of work describes an alternative method of generating iPSCs by using polycistronic lentiviral vector that may minimize the risks associated with viral vector-mediated reprogramming and animal derived products in the culture media.
    Matched MeSH terms: Induced Pluripotent Stem Cells/cytology*
  3. Nordin N, Lai MI, Veerakumarasivam A, Ramasamy R, Abdullah S, Wendy-Yeo WY, et al.
    Med J Malaysia, 2011 Mar;66(1):4-9.
    PMID: 23765134 MyJurnal
    The development of induced pluripotent stem cells (iPSCs) has been met with much enthusiasm and hailed as a breakthrough discovery by the scientific and research communities amidst the divisive and ongoing debates surrounding human embryonic stem cells (hESC) research. The discovery reveals the fact that embryonic pluripotency can be generated from adult somatic cells by the induction of appropriate transcriptional factor genes essential for maintaining the pluripotency. They provide an alternative source for pluripotent stem cells, thus representing a powerful new research tool besides their potential application in the field of regenerative medicine. In this review, the historical background of iPSCs generation will be discussed together with their properties and characteristics as well as their potential therapeutic applications.
    Matched MeSH terms: Induced Pluripotent Stem Cells*
  4. Ferdaos N, Nathan S, Nordin N
    Med J Malaysia, 2008 Jul;63 Suppl A:75-6.
    PMID: 19024991
    Amniotic fluid (AF) serves as an excellent alternative source of pluripotent stem cells, as they are not bound with ethical issues and the stem cells are more primitive than adult stem (AS) cells. Hence, they have higher potential. Here we aim to isolate and characterize pluripotent stem cells from mid-term and full-term pregnant rat amniotic fluid. The results demonstrate the evidence of heterogeneous population of cells in the amniotic fluid and some of the cells morphology shows similarity with ES cells.
    Matched MeSH terms: Pluripotent Stem Cells/cytology*
  5. Simat SF, Chua KH, Abdul Rahman H, Tan AE, Tan GC
    Med J Malaysia, 2008 Jul;63 Suppl A:53-4.
    PMID: 19024980
    The aim of the study is to evaluate the stemness gene expression of cultured human amniotic epithelial cells (HAECs) in serial passages. HAECs obtained from human term placentae were cultured in F12:DMEM(1:1) + 10% FBS +10ng/ml EGF in serial passages (P0, P1, P2 and P4). Quantitative RT-PCR was used to assess the gene expression analysis. The results showed that cultured HAECs expressed and downregulated the stemness genes expression for Oct-4, Sox-2, Nanog3, FGF4, Rex-1, FZD-9, BST-1 ABCG2. However, vimentin and nestin gene expression were upregulated. The results suggested that cultured HAECs may have pluripotent and multipotent properties.
    Matched MeSH terms: Pluripotent Stem Cells/cytology*; Pluripotent Stem Cells/transplantation
  6. Teoh HK, Cheong SK
    Malays J Pathol, 2012 Jun;34(1):1-13.
    PMID: 22870592 MyJurnal
    Induced pluripotent stem cells (iPSC) are derived from human somatic cells through ectopic expression of transcription factors. This landmark discovery has been considered as a major development towards patient-specific iPSC for various biomedical applications. Unlimited self renewal capacity, pluripotency and ease of accessibility to donor tissues contribute to the versatility of iPSC. The therapeutic potential of iPSC in regenerative medicine, cell-based therapy, disease modelling and drug discovery is indeed very promising. Continuous progress in iPSC technology provides clearer understanding of disease pathogenesis and ultimately new optimism in developing treatment or cure for human diseases.
    Matched MeSH terms: Induced Pluripotent Stem Cells/cytology*; Induced Pluripotent Stem Cells/transplantation
  7. Tai L, Teoh HK, Cheong SK
    Malays J Pathol, 2018 Dec;40(3):325-329.
    PMID: 30580364
    INTRODUCTION: Induced pluripotent stem cells (iPSC) that exhibit embryonic stem cell-like properties with unlimited self-renewal and multilineage differentiation properties, are a potential cell source in regenerative medicine and cell-based therapy. Although retroviral and lentiviral transduction methods to generate iPSC are well established, the risk of mutagenesis limits the use of these products for therapeutic applications.

    MATERIALS AND METHODS: In this study, reprogramming of human dermal fibroblasts (NHDF) into iPSC was carried out using non-integrative Sendai virus for transduction. The iPSC clones were characterised based on the morphological changes, gene expression of pluripotency markers, and spontaneous and directed differentiation abilities into cells of different germ layers.

    RESULTS: On day 18-25 post-transduction, colonies with embryonic stem cell-like morphology were obtained. The iPSC generated were free of Sendai genome and transgene after passage 10, as confirmed by RT-PCR. NHDF-derived iPSC expressed multiple pluripotency markers in qRT-PCR and immunofluorescence staining. When cultured in suspension for 8 days, iPSC successfully formed embryoid body-like spheres. NHDF-derived iPSC also demonstrated the ability to undergo directed differentiation into ectoderm and endoderm.

    CONCLUSION: NHDF were successfully reprogrammed into iPSC using non-integrating Sendai virus for transduction.

    Matched MeSH terms: Induced Pluripotent Stem Cells/cytology*
  8. Ting WJ, Shaw SW, Hii LY, Lin TY, Chang SC, Liu KY, et al.
    Taiwan J Obstet Gynecol, 2020 Jul;59(4):520-526.
    PMID: 32653123 DOI: 10.1016/j.tjog.2020.05.009
    OBJECTIVE: Bovine mastitis results in economic loss due to decrease in milk production. Antibiotic ointments are commonly used for treating. However, residue and anti-microbial resistance warranted attention progressively. Fortunately, stem cell anti-inflammatory properties and paracrine expression of cytokines accelerates wound healing and suppresses inflammatory reactions in mastitis. The objective of this study is to use the conditioned-Dulbecco's pluripotent stem cells (DPBS) from amniotic membrane stem cells (AMSCs) in treating bovine mastitis.

    MATERIALS AND METHODS: The cows with mastitis were divided into two groups. In antibiotic control group, the cows were given tetraneomycin ointment. In conditioned-DPBS of AMSCs treatment group, amniotic membrane was collected for AMSCs after delivery. With expression of surface antigen and potential of tri-linage differentiation, AMSCs were injected into mammary glands. Then, milk was sampled every three days to monitor the effect of both treatments. The quality of milk was measured with pH, titratable acidity, free calcium ions and somatic cell count.

    RESULTS: Our results demonstrated the Bovine AMSCs expressed CD44, low levels of CD4 and no CD105. Bovine AMSCs demonstrated the differentiation capability in the tri-cell lineages. Mastitis treatment with conditioned-DPBS from AMSCs (experimental group) and conventional antibiotics (control group) showed insignificant difference in pH value and titratable acidity. The level of ionic calcium concentration in the conditioned-DPBS group decreased from 3rd day to 12th day, while the level in the antibiotic group decreased from 0 day to 12th day. The somatic cell number was similar in both groups, which meet the standard of Taiwan milk collection.

    CONCLUSION: In conclusion, conditioned-DPBS from bovine AMSCs has the therapeutic potential to treat bovine mastitis and may replace antibiotics therapy in the future.

    Matched MeSH terms: Pluripotent Stem Cells
  9. Srijaya TC, Pradeep PJ, Zain RB, Musa S, Abu Kasim NH, Govindasamy V
    Stem Cells Int, 2012;2012:423868.
    PMID: 22654919 DOI: 10.1155/2012/423868
    Induced pluripotent stem cell-based therapy for treating genetic disorders has become an interesting field of research in recent years. However, there is a paucity of information regarding the applicability of induced pluripotent stem cells in dental research. Recent advances in the use of induced pluripotent stem cells have the potential for developing disease-specific iPSC lines in vitro from patients. Indeed, this has provided a perfect cell source for disease modeling and a better understanding of genetic aberrations, pathogenicity, and drug screening. In this paper, we will summarize the recent progress of the disease-specific iPSC development for various human diseases and try to evaluate the possibility of application of iPS technology in dentistry, including its capacity for reprogramming some genetic orodental diseases. In addition to the easy availability and suitability of dental stem cells, the approach of generating patient-specific pluripotent stem cells will undoubtedly benefit patients suffering from orodental disorders.
    Matched MeSH terms: Pluripotent Stem Cells; Induced Pluripotent Stem Cells
  10. Yap MS, Nathan KR, Yeo Y, Lim LW, Poh CL, Richards M, et al.
    Stem Cells Int, 2015;2015:105172.
    PMID: 26089911 DOI: 10.1155/2015/105172
    Human pluripotent stem cells (hPSCs) derived from either blastocyst stage embryos (hESCs) or reprogrammed somatic cells (iPSCs) can provide an abundant source of human neuronal lineages that were previously sourced from human cadavers, abortuses, and discarded surgical waste. In addition to the well-known potential therapeutic application of these cells in regenerative medicine, these are also various promising nontherapeutic applications in toxicological and pharmacological screening of neuroactive compounds, as well as for in vitro modeling of neurodegenerative and neurodevelopmental disorders. Compared to alternative research models based on laboratory animals and immortalized cancer-derived human neural cell lines, neuronal cells differentiated from hPSCs possess the advantages of species specificity together with genetic and physiological normality, which could more closely recapitulate in vivo conditions within the human central nervous system. This review critically examines the various potential nontherapeutic applications of hPSC-derived neuronal lineages and gives a brief overview of differentiation protocols utilized to generate these cells from hESCs and iPSCs.
    Matched MeSH terms: Pluripotent Stem Cells; Induced Pluripotent Stem Cells
  11. Khoo TS, Jamal R, Abdul Ghani NA, Alauddin H, Hussin NH, Abdul Murad NA
    Stem Cell Rev Rep, 2020 04;16(2):251-261.
    PMID: 32016780 DOI: 10.1007/s12015-020-09956-x
    The discovery of induced pluripotent stem (iPS) cells in 2006 marked a major breakthrough in regenerative medicine, enabling reversal of terminally differentiated somatic cells into pluripotent stem cells. The embryonic stem (ES) cells-like pluripotency and unlimited self-renewal capability of iPS cells have granted them enormous potential in many applications, particularly regenerative therapy. Unlike ES cells, however, iPS cells exhibit somatic memories which were carried over from the tissue of origin thus limited its translation in clinical applications. This review provides an updated overview of the retention of various somatic memories associated with the cellular identity, age and metabolism of tissue of origin in iPS cells. The influence of cell types, stage of maturation, age and various other factors on the retention of somatic memory has been discussed. Recent evidence of somatic memory in the form of epigenetic, transcriptomic, metabolic signatures and its functional manifestations in both in vitro and in vivo settings also have been reviewed. The increasing number of studies which had adopted isogenic cell lines for comparisons in recent years had facilitated the identification of genuine somatic memories. These memories functionally affect iPS cells and its derivatives and are potentially tumorigenic thus, raising concerns on their safety in clinical application. Various approaches for memory erasure had since being reported and their efficacies were highlighted in this review.
    Matched MeSH terms: Induced Pluripotent Stem Cells/cytology*; Induced Pluripotent Stem Cells/metabolism*
  12. Hiew VV, Simat SFB, Teoh PL
    Stem Cell Rev Rep, 2018 Feb;14(1):43-57.
    PMID: 28884292 DOI: 10.1007/s12015-017-9764-y
    Stem cells are well-known to have prominent roles in tissue engineering applications. Embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs) can differentiate into every cell type in the body while adult stem cells such as mesenchymal stem cells (MSCs) can be isolated from various sources. Nevertheless, an utmost limitation in harnessing stem cells for tissue engineering is the supply of cells. The advances in biomaterial technology allows the establishment of ex vivo expansion systems to overcome this bottleneck. The progress of various scaffold fabrication could direct stem cell fate decisions including cell proliferation and differentiation into specific lineages in vitro. Stem cell biology and biomaterial technology promote synergistic effect on stem cell-based regenerative therapies. Therefore, understanding the interaction of stem cell and biomaterials would allow the designation of new biomaterials for future clinical therapeutic applications for tissue regeneration. This review focuses mainly on the advances of natural and synthetic biomaterials in regulating stem cell fate decisions. We have also briefly discussed how biological and biophysical properties of biomaterials including wettability, chemical functionality, biodegradability and stiffness play their roles.
    Matched MeSH terms: Induced Pluripotent Stem Cells/metabolism
  13. Sriram S, Kang NY, Subramanian S, Nandi T, Sudhagar S, Xing Q, et al.
    Stem Cell Res Ther, 2021 02 05;12(1):113.
    PMID: 33546754 DOI: 10.1186/s13287-021-02171-6
    BACKGROUND: Despite recent rapid progress in method development and biological understanding of induced pluripotent stem (iPS) cells, there has been a relative shortage of tools that monitor the early reprogramming process into human iPS cells.

    METHODS: We screened the in-house built fluorescent library compounds that specifically bind human iPS cells. After tertiary screening, the selected probe was analyzed for its ability to detect reprogramming cells in the time-dependent manner using high-content imaging analysis. The probe was compared with conventional dyes in different reprogramming methods, cell types, and cell culture conditions. Cell sorting was performed with the fluorescent probe to analyze the early reprogramming cells for their pluripotent characteristics and genome-wide gene expression signatures by RNA-seq. Finally, the candidate reprogramming factor identified was investigated for its ability to modulate reprogramming efficiency.

    RESULTS: We identified a novel BODIPY-derived fluorescent probe, BDL-E5, which detects live human iPS cells at the early reprogramming stage. BDL-E5 can recognize authentic reprogramming cells around 7 days before iPS colonies are formed and stained positive with conventional pluripotent markers. Cell sorting of reprogrammed cells with BDL-E5 allowed generation of an increased number and higher quality of iPS cells. RNA sequencing analysis of BDL-E5-positive versus negative cells revealed early reprogramming patterns of gene expression, which notably included CREB1. Reprogramming efficiency was significantly increased by overexpression of CREB1 and decreased by knockdown of CREB1.

    CONCLUSION: Collectively, BDL-E5 offers a valuable tool for delineating the early reprogramming pathway and clinically applicable commercial production of human iPS cells.

    Matched MeSH terms: Induced Pluripotent Stem Cells*
  14. Fukunaga I, Shiga T, Chen C, Oe Y, Danzaki K, Ohta S, et al.
    Stem Cell Res, 2020 03;43:101674.
    PMID: 31926383 DOI: 10.1016/j.scr.2019.101674
    The gap junction beta-2 (GJB2) gene is the most common genetic cause of hereditary deafness worldwide. Especially, V37I mutation in GJB2 is most prevalent in Southeast Asia including Thailand, Malaysia, and Indonesia. Furthermore, it is the second most prevalent cause in Japan and China, and exhibits an audiometric phenotype of mild-to-moderate hearing loss. In this study, we generated induced pluripotent stem cells (iPSC) from peripheral blood mononuclear cells (PBMCs) of patient with homozygous V37I mutation. This iPSC line will be a powerful tool for investigating the pathogenesis and for developing a treatment for GJB2-related hearing loss.
    Matched MeSH terms: Induced Pluripotent Stem Cells/metabolism*
  15. Ong SB, Lee WH, Shao NY, Ismail NI, Katwadi K, Lim MM, et al.
    Stem Cell Reports, 2019 03 05;12(3):597-610.
    PMID: 30799273 DOI: 10.1016/j.stemcr.2019.01.017
    The relationship between diabetes and endothelial dysfunction remains unclear, particularly the association with pathological activation of calpain, an intracellular cysteine protease. Here, we used human induced pluripotent stem cells-derived endothelial cells (iPSC-ECs) to investigate the effects of diabetes on vascular health. Our results indicate that iPSC-ECs exposed to hyperglycemia had impaired autophagy, increased mitochondria fragmentation, and was associated with increased calpain activity. In addition, hyperglycemic iPSC-ECs had increased susceptibility to cell death when subjected to a secondary insult-simulated ischemia-reperfusion injury (sIRI). Importantly, calpain inhibition restored autophagy and reduced mitochondrial fragmentation, concurrent with maintenance of ATP production, normalized reactive oxygen species levels and reduced susceptibility to sIRI. Using a human iPSC model of diabetic endotheliopathy, we demonstrated that restoration of autophagy and prevention of mitochondrial fragmentation via calpain inhibition improves vascular integrity. Our human iPSC-EC model thus represents a valuable platform to explore biological mechanisms and new treatments for diabetes-induced endothelial dysfunction.
    Matched MeSH terms: Induced Pluripotent Stem Cells
  16. Higuchi A, Kao SH, Ling QD, Chen YM, Li HF, Alarfaj AA, et al.
    Sci Rep, 2015 Dec 14;5:18136.
    PMID: 26656754 DOI: 10.1038/srep18136
    The tentative clinical application of human pluripotent stem cells (hPSCs), such as human embryonic stem cells and human induced pluripotent stem cells, is restricted by the possibility of xenogenic contamination resulting from the use of mouse embryonic fibroblasts (MEFs) as a feeder layer. Therefore, we investigated hPSC cultures on biomaterials with different elasticities that were grafted with different nanosegments. We prepared dishes coated with polyvinylalcohol-co-itaconic acid hydrogels grafted with an oligopeptide derived from vitronectin (KGGPQVTRGDVFTMP) with elasticities ranging from 10.3 to 30.4 kPa storage moduli by controlling the crosslinking time. The hPSCs cultured on the stiffest substrates (30.4 kPa) tended to differentiate after five days of culture, whereas the hPSCs cultured on the optimal elastic substrates (25 kPa) maintained their pluripotency for over 20 passages under xeno-free conditions. These results indicate that cell culture matrices with optimal elasticity can maintain the pluripotency of hPSCs in culture.
    Matched MeSH terms: Pluripotent Stem Cells/cytology*; Pluripotent Stem Cells/metabolism
  17. Chen YM, Chen LH, Li MP, Li HF, Higuchi A, Kumar SS, et al.
    Sci Rep, 2017 03 23;7:45146.
    PMID: 28332572 DOI: 10.1038/srep45146
    Establishing cultures of human embryonic (ES) and induced pluripotent (iPS) stem cells in xeno-free conditions is essential for producing clinical-grade cells. Development of cell culture biomaterials for human ES and iPS cells is critical for this purpose. We designed several structures of oligopeptide-grafted poly (vinyl alcohol-co-itaconic acid) hydrogels with optimal elasticity, and prepared them in formations of single chain, single chain with joint segment, dual chain with joint segment, and branched-type chain. Oligopeptide sequences were selected from integrin- and glycosaminoglycan-binding domains of the extracellular matrix. The hydrogels grafted with vitronectin-derived oligopeptides having a joint segment or a dual chain, which has a storage modulus of 25 kPa, supported the long-term culture of human ES and iPS cells for over 10 passages. The dual chain and/or joint segment with cell adhesion molecules on the hydrogels facilitated the proliferation and pluripotency of human ES and iPS cells.
    Matched MeSH terms: Pluripotent Stem Cells/cytology*; Pluripotent Stem Cells/metabolism*
  18. Hamid AA, Joharry MK, Mun-Fun H, Hamzah SN, Rejali Z, Yazid MN, et al.
    Reprod Biol, 2017 Mar;17(1):9-18.
    PMID: 28262444 DOI: 10.1016/j.repbio.2017.02.001
    Amniotic fluid (AF) is now known to harbor highly potent stem cells, making it an excellent source for cell therapy. However, most of the stem cells isolated are from AF of mid-term pregnancies in which the collection procedure involves an invasive technique termed amniocentesis. This has limited the access in getting the fluid as the technique imposes certain level of risks to the mother as well as to the fetus. Alternatively, getting AF from full-term pregnancies or during deliveries would be a better resolution. Unfortunately, very few studies have isolated stem cells from AF at this stage of gestation, the fluid that is merely discarded. The question remains whether full-term AF harbors stem cells of similar potency as of the stem cells of mid-term AF. Here, we aim to review the prospect of having this type of stem cells by first looking at the origin and contents of AF particularly during different gestation period. We will then discuss the possibility that the AF, at full term, contains a population of highly potent stem cells. These stem cells are distinct from, and probably more potent than the AF mesenchymal stem cells (AF-MSCs) isolated from full-term AF. By comparing the studies on stem cells isolated from mid-term versus full-term AF from various species, we intend to address the prospect of having highly potent amniotic fluid stem cells from AF of full-term pregnancies in human and animals.
    Matched MeSH terms: Pluripotent Stem Cells/cytology
  19. Chiou SH, Ong HKA, Chou SJ, Aldoghachi AF, Loh JK, Verusingam ND, et al.
    Prog Mol Biol Transl Sci, 2023;199:131-154.
    PMID: 37678969 DOI: 10.1016/bs.pmbts.2023.04.002
    Mesenchymal stem cells (MSCs) differentiated from human induced pluripotent stem cells (iPSC) or induced MSC (iMSCs) are expected to address issues of scalability and safety as well as the difficulty in producing homogenous clinical grade MSCs as demonstrated by the promising outcomes from preclinical and clinical trials, currently ongoing. The assessment of iMSCs based in vitro and in vivo studies have thus far showed more superior performance as compared to that of the primary or native human MSCs, in terms of cell proliferation, expansion capacity, immunomodulation properties as well as the influence of paracrine signaling and exosomal influence in cell-cell interaction. In this chapter, an overview of current well-established methods in generating a sustainable source of iMSCs involving well defined culture media is discussed followed by the properties of iMSC as compared to that of MSC and its promising prospects for continuous development into potential clinical grade applications.
    Matched MeSH terms: Induced Pluripotent Stem Cells*
  20. Lu J, Wei H, Wu J, Jamil MF, Tan ML, Adenan MI, et al.
    PLoS One, 2014;9(12):e115648.
    PMID: 25535742 DOI: 10.1371/journal.pone.0115648
    INTRODUCTION: Mitragynine is a major bioactive compound of Kratom, which is derived from the leave extracts of Mitragyna speciosa Korth or Mitragyna speciosa (M. speciosa), a medicinal plant from South East Asia used legally in many countries as stimulant with opioid-like effects for the treatment of chronic pain and opioid-withdrawal symptoms. Fatal incidents with Mitragynine have been associated with cardiac arrest. In this study, we determined the cardiotoxicity of Mitragynine and other chemical constituents isolated using human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs).

    METHODS AND RESULTS: The rapid delayed rectifier potassium current (IKr), L-type Ca2+ current (ICa,L) and action potential duration (APD) were measured by whole cell patch-clamp. The expression of KCNH2 and cytotoxicity was determined by real-time PCR and Caspase activity measurements. After significant IKr suppression by Mitragynine (10 µM) was confirmed in hERG-HEK cells, we systematically examined the effects of Mitragynine and other chemical constituents in hiPSC-CMs. Mitragynine, Paynantheine, Speciogynine and Speciociliatine, dosage-dependently (0.1∼100 µM) suppressed IKr in hiPSC-CMs by 67%∼84% with IC50 ranged from 0.91 to 2.47 µM. Moreover, Mitragynine (10 µM) significantly prolonged APD at 50 and 90% repolarization (APD50 and APD90) (439.0±11.6 vs. 585.2±45.5 ms and 536.0±22.6 vs. 705.9±46.1 ms, respectively) and induced arrhythmia, without altering the L-type Ca2+ current. Neither the expression, and intracellular distribution of KCNH2/Kv11.1, nor the Caspase 3 activity were significantly affected by Mitragynine.

    CONCLUSIONS: Our study indicates that Mitragynine and its analogues may potentiate Torsade de Pointes through inhibition of IKr in human cardiomyocytes.

    Matched MeSH terms: Induced Pluripotent Stem Cells/cytology
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