Displaying publications 1 - 20 of 70 in total

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  1. Fulltext A Comparison of Culture Characteristics between Human Amniotic Mesenchymal Stem Cells and Dental Stem Cells
    Yusoff NH, Alshehadat SA, Azlina A, Kannan TP, Hamid SS
    Trop Life Sci Res, 2015 Apr;26(1):21-9.
    PMID: 26868590 MyJurnal
    In the past decade, the field of stem cell biology is of major interest among researchers due to its broad therapeutic potential. Stem cells are a class of undifferentiated cells that are able to differentiate into specialised cell types. Stem cells can be classified into two main types: adult stem cells (adult tissues) and embryonic stem cells (embryos formed during the blastocyst phase of embryological development). This review will discuss two types of adult mesenchymal stem cells, dental stem cells and amniotic stem cells, with respect to their differentiation lineages, passage numbers and animal model studies. Amniotic stem cells have a greater number of differentiation lineages than dental stem cells. On the contrary, dental stem cells showed the highest number of passages compared to amniotic stem cells. For tissue regeneration based on animal studies, amniotic stem cells showed the shortest time to regenerate in comparison with dental stem cells.
  2. Amniotic Membrane Enhance the Effect of Vascular Endothelial Growth Factor on the Angiogenic Marker Expression of Stem Cells from Human Exfoliated Deciduous Teeth
    Yusof MFH, Hashim SNM, Zahari W, Chandra H, Noordin KBAA, Kannan TP, et al.
    Appl Biochem Biotechnol, 2020 May;191(1):177-190.
    PMID: 32096060 DOI: 10.1007/s12010-020-03266-1
    Previously, it was reported that human amniotic membrane (AM) induced stem cells from human deciduous exfoliated teeth (SHED) endothelial-like-cell differentiation. This interesting effect of AM matrix on SHED demands further elucidation. Objective of this in vitro work was to study the effect of 24-h VEGF induced on SHED endothelial differentiation when seeded on acellular stromal side (SS) of AM matrix. Stemness of SHED was identified by flow cytometry. Cell attachment and morphological changes towards the matrix was observed by scanning electron microscopy. Protein expression of endothelial marker was examined by Western blot. The expression of stem cells and endothelial-specific gene markers of VEGF-induced SHED cultured on human AM was inspected via reverse transcriptase-polymerase chain reaction. Results showed SHED at both passages retain stemness property. Ang-1 protein was expressed in SHED. Cells treated with VEGF and cultured on AM transformed attached well to AM. VEGF-induced SHED expressed both stem cell and endothelial-specific markers throughout the treatments and timeline. Interestingly, prolonged VEGF treatment increased the expression of Cox-2 and VE-Cadherin genes in all treated groups when compared to SHED. It was concluded that the VEGF-induced SHED showed better expression of endothelial-specific markers when cultured on SS of AM, with prolonged VEGF treatment.
  3. Fulltext Angiogenic and osteogenic potentials of dental stem cells in bone tissue engineering
    Yusof MFH, Zahari W, Hashim SNM, Osman ZF, Chandra H, Kannan TP, et al.
    J Oral Biol Craniofac Res, 2017 10 19;8(1):48-53.
    PMID: 29556464 DOI: 10.1016/j.jobcr.2017.10.003
    Manipulation of dental stem cells (DSCs) using current technologies in tissue engineering unveil promising prospect in regenerative medicine. DSCs have shown to possess angiogenic and osteogenic potential in both in vivo and in vitro. Neural crest derived DSCs can successfully be isolated from various dental tissues, exploiting their intrinsic great differentiation potential. In this article, researcher team intent to review the characteristics of DSCs, with focus on their angiogenic and osteogenic differentiation lineage. Clinical data on DSCs are still lacking to prove their restorative abilities despite extensive contemporary literature, warranting research to further validate their application for bone tissue engineering.
  4. Fulltext The antibacterial properties of euphorbia tirucalli stem extracts against dental caries-related bacteria
    Yi, Q.S., Wan Zarina, Z.A., Nurulhidayah, C.N., Mohamad Ezany, Y., Azlina, A., Suharni, M.
    Medicine & Health, 2017;12(1):34-41.
    MyJurnal
    Euphorbia tirucalli dilaporkan mempunyai aktiviti antibakteria terhadap pelbagai
    mikroorganisma. Kajian in vitro ini bertujuan untuk menilai ciri-ciri antibakteria
    ekstrak (metanol, etanol dan ekstrak akueus) batang Euphorbia tirucalli terhadap
    bakteria yang berkaitan dengan karies gigi, iaitu Streptococcus mutans (S. mutans)
    dan Streptococcus sobrinus (S. sobrinus). Sifat-sifat antibakteria telah ditentukan
    menggunakan ujian resapan agar berlubang pada kepekatan ekstrak yang berbeza
    (10, 20 dan 30 mg/ml). Komersial amoxicillin (10 µg) telah digunakan sebagai
    kawalan positif manakala pelarut yang sesuai telah digunakan sebagai kawalan
    negatif. Ekstrak metanol dan ethanol daripada batang Euphorbia tirucalli didapati
    berkesan terhadap S. mutans dan S. sobrinus. Walau bagaimanapun, ekstrak akueus
    batang Euphorbia tirucalli tidak menunjukkan aktiviti terhadap kedua-dua strain
    bakteria. Perbezaan dalam ciri-ciri antibakteria dalam perbezaan ekstrak Euphorbia
    tirucalli mungkin disebabkan oleh perbezaan dalam juzuk fitokimia.
  5. Nutrient composition, antioxidant properties, and anti-proliferative activity of Lignosus rhinocerus Cooke sclerotium
    Yap YH, Tan N, Fung S, Aziz AA, Tan C, Ng S
    J Sci Food Agric, 2013 Sep;93(12):2945-52.
    PMID: 23460242 DOI: 10.1002/jsfa.6121
    Lignosus rhinocerus (tiger milk mushroom) is an important medicinal mushroom used in Southeast Asia and China, and its sclerotium can be developed into functional food/nutraceuticals. The nutrient composition, antioxidant properties, and anti-proliferative activity of wild type and a cultivated strain of L. rhinocerus sclerotia were investigated.
  6. The Combined Effect of Substrate Stiffness and Surface Topography on Chondrogenic Differentiation of Mesenchymal Stem Cells
    Wu Y, Yang Z, Law JB, He AY, Abbas AA, Denslin V, et al.
    Tissue Eng Part A, 2017 01;23(1-2):43-54.
    PMID: 27824280 DOI: 10.1089/ten.TEA.2016.0123
    Stem cell differentiation is guided by contact with the physical microenvironment, influence by both topography and mechanical properties of the matrix. In this study, the combined effect of substratum nano-topography and mechanical stiffness in directing mesenchymal stem cell (MSC) chondrogenesis was investigated. Three polyesters of varying stiffness were thermally imprinted to create nano-grating or pillar patterns of the same dimension. The surface of the nano-patterned substrate was coated with chondroitin sulfate (CS) to provide an even surface chemistry, with cell-adhesive and chondro-inductive properties, across all polymeric substrates. The surface characteristic, mechanical modulus, and degradation of the CS-coated patterned polymeric substrates were analyzed. The cell morphology adopted on the nano-topographic surfaces were accounted by F-actin distribution, and correlated to the cell proliferation and chondrogenic differentiation outcomes. Results show that substratum stiffness and topographical cues affected MSC morphology and aggregation, and influenced the phenotypic development at the earlier stage of chondrogenic differentiation. Hyaline-like cartilage with middle/deep zone cartilage characteristics was generated on softer pillar surface, while on stiffer nano-pillar material MSCs showed potential to generate constituents of hyaline/fibro/hypertrophic cartilage. Fibro/superficial zone-like cartilage could be derived from nano-grating of softer stiffness, while stiffer nano-grating resulted in insignificant chondrogenesis. This study demonstrates the possibility of refining the phenotype of cartilage generated from MSCs by manipulating surface topography and material stiffness.
  7. Fulltext Custom-Made Articulating Spacer (CUMARS): The Resolution of Periosteal Reaction and Femur Remodelling in Periprosthetic Hip Infection
    Wong R, Abbas AA, Ayob KA, Nasuruddin H, Selvaratnam V
    Cureus, 2023 Jul;15(7):e41669.
    PMID: 37575748 DOI: 10.7759/cureus.41669
    Periprosthetic joint infection (PJI) is one of the most common complications after total hip arthroplasty (THA). Two-stage revision surgery is one of the treatment options for PJI, however, it has been associated with poor patient tolerance, reduced patient mobility, and periarticular tissue contracture leading to difficulty during second-stage reconstruction. The custom-made articulating spacer (CUMARS) was developed to provide an alternative that is better tolerated and to reduce the complexity of second-stage reconstruction. This study details the treatment of a patient with PJI post-THA with significant periosteal reaction using a CUMARS construct, which enabled immediate post-operative weight bearing, eventual eradication of infection, restoration of femoral bone stock, and avoidance of second-stage reconstruction.
  8. A clinical evaluation of bleeding patterns, adverse effects, and satisfaction with the subdermal etonogestrel implant among postpartum and non-postpartum users
    Wahab NA, Rahman NA, Mustafa KB, Awang M, Sidek AA, Ros RM
    Int J Gynaecol Obstet, 2016 Feb;132(2):237-8.
    PMID: 26617248 DOI: 10.1016/j.ijgo.2015.07.022
  9. Fulltext Genotypic to Phenotypic Resistance Discrepancies Identified Involving β-Lactamase Genes, blaKPC, blaIMP, blaNDM-1, and blaVIM in Uropathogenic Klebsiella pneumoniae
    Urmi UL, Nahar S, Rana M, Sultana F, Jahan N, Hossain B, et al.
    Infect Drug Resist, 2020;13:2863-2875.
    PMID: 32903880 DOI: 10.2147/IDR.S262493
    Introduction: Klebsiella pneumoniae carbapenemase (KPC) belongs to the Group-A β-lactamases that incorporate serine at their active site and hydrolyze various penicillins, cephalosporins, and carbapenems. Metallo-beta-lactamases (MBLs) are group-B enzymes that contain one or two essential zinc ions in the active sites and hydrolyze almost all clinically available β-lactam antibiotics. Klebsiella pneumoniae remains the pathogen with the most antimicrobial resistance to KPC and MBLs.

    Methods: This research investigated the blaKPC, and MBL genes, namely, blaIMP, blaVIM, and blaNDM-1 and their phenotypic resistance to K. pneumoniae isolated from urinary tract infections (UTI) in Bangladesh. Isolated UTI K. pneumoniae were identified by API-20E and 16s rDNA gene analysis. Their phenotypic antimicrobial resistance was examined by the Kirby-Bauer disc diffusion method, followed by minimal inhibitory concentration (MIC) determination. blaKPC, blaIMP, blaNDM-1, and blaVIM genes were evaluated by polymerase chain reactions (PCR) and confirmed by sequencing.

    Results: Fifty-eight K. pneumoniae were identified from 142 acute UTI cases. Their phenotypic resistance to amoxycillin-clavulanic acid, cephalexin, cefuroxime, ceftriaxone, and imipenem were 98.3%, 100%, 96.5%, 91.4%, 75.1%, respectively. Over half (31/58) of the isolates contained either blaKPC or one of the MBL genes. Individual prevalence of blaKPC, blaIMP, blaNDM-1, and blaVIM were 15.5% (9), 10.3% (6), 22.4% (13), and 19% (11), respectively. Of these, eight isolates (25.8%, 8/31) were found to have two genes in four different combinations. The co-existence of the ESBL genes generated more resistance than each one individually. Some isolates appeared phenotypically susceptible to imipenem in the presence of blaKPC, blaIMP, blaVIM, and blaNDM-1 genes, singly or in combination.

    Conclusion: The discrepancy of genotype and phenotype resistance has significant consequences for clinical bacteriology, precision in diagnosis, the prudent selection of antimicrobials, and rational prescribing. Heterogeneous phenotypes of antimicrobial susceptibility testing should be taken seriously to avoid inappropriate diagnostic and therapeutic decisions.

  10. Effect of growth differentiation factor 5 on the proliferation and tenogenic differentiation potential of human mesenchymal stem cells in vitro
    Tan SL, Ahmad RE, Ahmad TS, Merican AM, Abbas AA, Ng WM, et al.
    Cells Tissues Organs (Print), 2012;196(4):325-38.
    PMID: 22653337
    The use of growth differentiation factor 5 (GDF-5) in damaged tendons has been shown to improve tendon repair. It has been hypothesized that further improvements may be achieved when GDF-5 is used to promote cell proliferation and induce tenogenic differentiation in human bone marrow-derived mesenchymal stem cells (hMSCs). However, the optimal conditions required to produce these effects on hMSCs have not been demonstrated in previous studies. A study to determine cell proliferation and tenogenic differentiation in hMSCs exposed to different concentrations of GDF-5 (0, 5, 25, 50, 100 and 500 ng/ml) was thus conducted. No significant changes were observed in the cell proliferation rate in hMSCs treated at different concentrations of GDF-5. GDF-5 appeared to induce tenogenic differentiation at 100 ng/ml, as reflected by (1) a significant increase in total collagen expression, similar to that of the primary native human tenocyte culture; (2) a significant upregulation in candidate tenogenic marker gene expression, i.e. scleraxis, tenascin-C and type-I collagen; (3) the ratio of type-I collagen to type-III collagen expression was elevated to levels similar to that of human tenocyte cultures, and (4) a significant downregulation of the non-tenogenic marker genes runt-related transcription factor 2 and sex determining region Y (SRY)-box 9 at day 7 of GDF-5 induction, further excluding hMSC differentiation into other lineages. In conclusion, GDF-5 does not alter the proliferation rates of hMSCs, but, instead, induces an optimal tenogenic differentiation response at 100 ng/ml.
  11. Mutagenicity of CORAGRAF and REKAGRAF in the Ames test
    Suzina AH, Azlina A, Shamsuria O, Samsudin AR
    Med J Malaysia, 2004 May;59 Suppl B:105-6.
    PMID: 15468840
    Mutagenicity of CORAGRAF (natural coral) and REKAGRAF (hydroxyapatite) was tested in Ames test with and without an external metabolic activation system (S9). The test revealed no mutagenic activity of both locally produced osseous substitutes.
  12. Fulltext Multiplex Polymerase Chain Reaction (PCR) efficiency in detection of pathogenic Escherichia coli O157:H7
    Suria, M. S., Adlin Azlina, A. K., Mohd Afendy, A. T., Zamri, I.
    International Food Research Journal, 2013;20(6):3307-3311.
    MyJurnal
    Shiga toxin-producing E. coli (STEC) is an important foodborne pathogen causing diarrhea, hemorrhagic colitis and hemolytic-uremic syndrome in humans. STEC is an implicated in the vast majority of outbreaks, widely via consumption of STEC contaminated beef, as important vehicle of transmission of this organism to human. The E. coli O157:H7 serotype is traditionally identified by serological identification of the somatic antigen (O157) and structural flagella (H7). In this study, the bacteria were identified as STEC serotype O157:H7 with three primer pairs that amplified fragments of secD, rfbE and fliC genes in PCR assays. These primer pairs specifically amplified different sizes of target genes: a 244bp region of the E. coli diagnostic marker gene (secD); a 317bp region of the O157 lipopolysacharide (LPS) gene (rfbE); and a 381bp region of the H7 flagellin gene (fliC). The singleplex, duplex and triplex PCR assay developed in this study have a sensitivity limit at 2.8 x 103, 2.8 x 105 and 2.8 x 107 CFU/ml of E. coli O157:H7, respectively. Sensitivity to detect trace amount of E. coli O157:H7 DNA was reduced as the number of primer used was increased for competing to the same DNA template.
  13. Occurrence of vancomycin-resistant enterococci in ducks in Malaysia
    Shah-Majid M, Azlina AM, Ana Maria AR, Zaharah B, Norhaliza AH
    Vet Rec, 2004 Nov 20;155(21):680-1.
    PMID: 15581146
  14. Fulltext Platelet-rich concentrate in serum free medium enhances osteogenic differentiation of bone marrow-derived human mesenchymal stromal cells
    Samuel S, Ahmad RE, Ramasamy TS, Karunanithi P, Naveen SV, Murali MR, et al.
    PeerJ, 2016;4:e2347.
    PMID: 27651984 DOI: 10.7717/peerj.2347
    Previous studies have shown that platelet concentrates used in conjunction with appropriate growth media enhance osteogenic differentiation of human mesenchymal stromal cells (hMSCs). However, their potential in inducing osteogenesis of hMSCs when cultured in serum free medium has not been explored. Furthermore, the resulting osteogenic molecular signatures of the hMSCs have not been compared to standard osteogenic medium. We studied the effect of infrequent supplementation (8-day interval) of 15% non-activated platelet-rich concentrate (PRC) in serum free medium on hMSCs proliferation and differentiation throughout a course of 24 days, and compared the effect with those cultured in a standard osteogenic medium (OM). Cell proliferation was analyzed by alamar blue assay. Gene expression of osteogenic markers (Runx2, Collagen1, Alkaline Phosphatase, Bone morphogenetic protein 2, Osteopontin, Osteocalcin, Osteonectin) were analyzed using Q-PCR. Immunocytochemical staining for osteocalcin, osteopontin and transcription factor Runx2 were done at 8, 16 and 24 days. Biochemical assays for the expression of ALP and osteocalcin were also performed at these time-points. Osteogenic differentiation was further confirmed qualitatively by Alizarin Red S staining that was quantified using cetylpyridinium chloride. Results showed that PRC supplemented in serum free medium enhanced hMSC proliferation, which peaked at day 16. The temporal pattern of gene expression of hMSCs under the influence of PRC was comparable to that of the osteogenic media, but at a greater extent at specific time points. Immunocytochemical staining revealed stronger staining for Runx2 in the PRC-treated group compared to OM, while the staining for Osteocalcin and Osteopontin were comparable in both groups. ALP activity and Osteocalcin/DNA level were higher in the PRC group. Cells in the PRC group had similar level of bone mineralization as those cultured in OM, as reflected by the intensity of Alizarin red stain. Collectively, these results demonstrate a great potential of PRC alone in inducing proliferation of hMSCs without any influence from other lineage-specific growth media. PRC alone has similar capacity to enhance hMSC osteogenic differentiation as a standard OM, without changing the temporal profile of the differentiation process. Thus, PRC could be used as a substitute medium to provide sufficient pool of pre-differentiated hMSCs for potential clinical application in bone regeneration.
  15. Fulltext Entomological study of chikungunya infections in the State of Kelantan, Malaysia
    Rozilawati H, Faudzi AY, Rahidah AA, Azlina AH, Abdullah AG, Amal NM, et al.
    Indian J Med Res, 2011 Jun;133:670-3.
    PMID: 21727669
    Chikungunya infection has become a public health threat in Malaysia since the 2008 nationwide outbreaks. Aedes albopictus Skuse has been identified as the chikungunya vector in Johor State during the outbreaks. In 2009, several outbreaks had been reported in the State of Kelantan. Entomological studies were conducted in Kelantan in four districts, namely Jeli, Tumpat, Pasir Mas and Tanah Merah to identify the vector responsible for the virus transmission.
  16. Fulltext Gene expression profiles in human HepG2 cells treated with extracts of the Tamarindus indica fruit pulp
    Razali N, Aziz AA, Junit SM
    Genes Nutr, 2010 Dec;5(4):331-41.
    PMID: 21189869 DOI: 10.1007/s12263-010-0187-5
    Tamarindus indicaL. (T. indica) or locally known as asam jawa belongs to the family of Leguminosae. The fruit pulp had been reported to have antioxidant activities and possess hypolipidaemic effects. In this study, we attempted to investigate the gene expression patterns in human hepatoma HepG2 cell line in response to treatment with low concentration of the fruit pulp extracts. Microarray analysis using Affymetrix Human Genome 1.0 S.T arrays was used in the study. Microarray data were validated using semi-quantitative RT-PCR and real-time RT-PCR. Amongst the significantly up-regulated genes were those that code for the metallothioneins (MT1M, MT1F, MT1X) and glutathione S-transferases (GSTA1, GSTA2, GST02) that are involved in stress response. APOA4, APOA5, ABCG5 and MTTP genes were also significantly regulated that could be linked to hypolipidaemic activities of the T. indica fruit pulp.
  17. Impaired vasocontractile responses to adenosine in chorionic vessels of human term placenta from pregnant women with pre-existing and gestational diabetes
    Razak AA, Leach L, Ralevic V
    Diab Vasc Dis Res, 2018 11;15(6):528-540.
    PMID: 30130976 DOI: 10.1177/1479164118790904
    BACKGROUND: There is clinical and experimental evidence for altered adenosine signalling in the fetoplacental circulation in pregnancies complicated by diabetes, leading to adenosine accumulation in the placenta. However, the consequence for fetoplacental vasocontractility is unclear. This study examined contractility to adenosine of chorionic vessels from type 1 diabetes mellitus, gestational diabetes mellitus and normal pregnancies.

    METHODS: Chorionic arteries and veins were isolated from human placenta from normal, gestational diabetes mellitus and type 1 diabetes mellitus pregnancies. Isometric tension recording measured responses to adenosine and the thromboxane A2 analogue U46619 (thromboxane A2 mediates fetoplacental vasoconstriction to adenosine). Adenosine and thromboxane prostanoid receptor protein expression was determined by immunoblotting.

    RESULTS: Adenosine elicited contractions in chorionic arteries and veins which were impaired in both gestational diabetes mellitus and type 1 diabetes mellitus. Contractions to potassium chloride were unchanged. Adenosine A2A and A2B receptor protein levels were not different in gestational diabetes mellitus and normal pregnancies. Contractions to U46619 were unaltered in gestational diabetes mellitus arteries and increased in type 1 diabetes mellitus arteries. Overnight storage of vessels restored contractility to adenosine in gestational diabetes mellitus arteries and normalized contraction to U46619 in type 1 diabetes mellitus arteries.

    CONCLUSION: These data are consistent with the concept of aberrant adenosine signalling in diabetes; they show for the first time that this involves impaired adenosine contractility of the fetoplacental vasculature.

  18. Fulltext Kimura's disease of the parotid: A complete clinical-radiological-pathology report
    Ragu R, Eng JY, Azlina AR
    Med J Malaysia, 2014 Aug;69(4):199-201.
    PMID: 25500854
    Kimura's disease is rare chronic inflammatory disease with a distinct clinicopathological entity. It has three major components; inflammatory, vascular and fibrosis. It has to be considered as a differential diagnosis in young patient presenting with head and neck swelling. Although of unknown aetiology many hypothesis has been postulated. Inflammation is the most prominent and predominating characteristic in this disease. Although reported to be predominant in Asian literature regarding this disease is scanty. We report a complete clinical-radiological and pathological picture of this disease.
  19. Gastrointestinal Parasites in Asian and African Elephants: A Systematic Review
    Qurratul-Saadah Z, Che-Amat A, Syed-Hussain SS, Kamaludden J, Ariffin SMZ, Basripuzi NH, et al.
    Trop Biomed, 2023 Mar 01;40(1):55-64.
    PMID: 37356004 DOI: 10.47665/tb.40.1.012
    Gastrointestinal parasites (GIPs) in elephants have been reported in several studies over the last decades. Nonetheless, comprehensive data on clinicopathology of elephant GIPs, parasite burden threshold value, and the effectiveness of conventional anthelmintic drugs are still lacking. Herein, we have systematically reviewed the available knowledge on elephant GIPs identified among different parts of the world based on their prevalence, epidemiology, pathology, diagnosis, treatment, and control. Two electronic databases were searched for publications that met the inclusion criteria. About19 English journal articles published between year of 2011- 2021 were included. The main GIPs reported in elephants were Cyathostomidae (at least 14 species), Ancylostomidae, Haemonchus contortus, Trichostrongylus colubriformis, Oesophagostomum columbianum, Oesophagostomum aceleatum, Ascarids, Trichurids, Strongyloides, Anophlocephalidae, flukes, and Coccidia across different parts of the world, including Malaysia, Indonesia, Thailand, Myanmar, Sri Lanka, India, Kenya, Nigeria, and South Africa. Most elephants show no clinical signs until the equilibrium between parasite and host is disturbed. The common diagnostic methods for GIPs are traditional direct smear, faecal floatation, sedimentation, and McMaster egg counting technique, all involving morphological identification. However, some articles described the use of molecular detection to characterise common GIPs of elephants. Although benzimidazoles and macrocyclic lactones group of anthelmintic are the most conventional GIPs treatment and control for captive and semi-captive elephants, there is limited data on the threshold value of faecal egg count as the baseline for treatment decision. Over the last decades, various studies regarding elephant GIPs have been conducted. However, more focused and systematic studies are required to enhance our knowledge in multiple aspects of elephant parasitology to find effective solutions and improve elephant health.
  20. Fulltext Enhancement of mesenchymal stem cell chondrogenesis with short-term low intensity pulsed electromagnetic fields
    Parate D, Franco-Obregón A, Fröhlich J, Beyer C, Abbas AA, Kamarul T, et al.
    Sci Rep, 2017 08 25;7(1):9421.
    PMID: 28842627 DOI: 10.1038/s41598-017-09892-w
    Pulse electromagnetic fields (PEMFs) have been shown to recruit calcium-signaling cascades common to chondrogenesis. Here we document the effects of specified PEMF parameters over mesenchymal stem cells (MSC) chondrogenic differentiation. MSCs undergoing chondrogenesis are preferentially responsive to an electromagnetic efficacy window defined by field amplitude, duration and frequency of exposure. Contrary to conventional practice of administering prolonged and repetitive exposures to PEMFs, optimal chondrogenic outcome is achieved in response to brief (10 minutes), low intensity (2 mT) exposure to 6 ms bursts of magnetic pulses, at 15 Hz, administered only once at the onset of chondrogenic induction. By contrast, repeated exposures diminished chondrogenic outcome and could be attributed to calcium entry after the initial induction. Transient receptor potential (TRP) channels appear to mediate these aspects of PEMF stimulation, serving as a conduit for extracellular calcium. Preventing calcium entry during the repeated PEMF exposure with the co-administration of EGTA or TRP channel antagonists precluded the inhibition of differentiation. This study highlights the intricacies of calcium homeostasis during early chondrogenesis and the constraints that are placed on PEMF-based therapeutic strategies aimed at promoting MSC chondrogenesis. The demonstrated efficacy of our optimized PEMF regimens has clear clinical implications for future regenerative strategies for cartilage.
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