Displaying publications 41 - 60 of 145 in total

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  1. Fulltext Isolation, characterization and the multi-lineage differentiation potential of rabbit bone marrow-derived mesenchymal stem cells
    Tan SL, Ahmad TS, Selvaratnam L, Kamarul T
    J Anat, 2013 Apr;222(4):437-50.
    PMID: 23510053 DOI: 10.1111/joa.12032
    Mesenchymal stem cells (MSCs) are recognized by their plastic adherent ability, fibroblastic-like appearance, expression of specific surface protein markers, and are defined by their ability to undergo multi-lineage differentiation. Although rabbit bone marrow-derived MSCs (rbMSCs) have been used extensively in previous studies especially in translational research, these cells have neither been defined morphologically and ultrastructurally, nor been compared with their counterparts in humans in their multi-lineage differentiation ability. A study was therefore conducted to define the morphology, surface marker proteins, ultrastructure and multi-lineage differentiation ability of rbMSCs. Herein, the primary rbMSC cultures of three adult New Zealand white rabbits (at least 4 months old) were used for three independent experiments. rbMSCs were isolated using the gradient-centrifugation method, an established technique for human MSCs (hMSCs) isolation. Cells were characterized by phase contrast microscopy observation, transmission electron microscopy analysis, reverse transcriptase-polymerase chain reaction (PCR) analysis, immunocytochemistry staining, flow cytometry, alamarBlue(®) assay, histological staining and quantitative (q)PCR analysis. The isolated plastic adherent cells were in fibroblastic spindle-shape and possessed eccentric, irregular-shaped nuclei as well as rich inner cytoplasmic zones similar to that of hMSCs. The rbMSCs expressed CD29, CD44, CD73, CD81, CD90 and CD166, but were negative (or dim positive) for CD34, CD45, CD117 and HLD-DR. Despite having similar morphology and phenotypic expression, rbMSCs possessed significantly larger cell size but had a lower proliferation rate as compared with hMSCs. Using established protocols to differentiate hMSCs, rbMSCs underwent osteogenic, adipogenic and chondrogenic differentiation. Interestingly, differentiated rbMSCs demonstrated higher levels of osteogenic (Runx2) and chondrogenic (Sox9) gene expressions than that of hMSCs (P  0.05). rbMSCs possess similar morphological characteristics to hMSCs, but have a higher potential for osteogenic and chondrogenic differentiation, despite having a lower cell proliferation rate than hMSCs. The characteristics reported here may be used as a comprehensive set of criteria to define or characterize rbMSCs.
  2. Restoring the IL-1β/NF-κB-induced impaired chondrogenesis by diallyl disulfide in human adipose-derived mesenchymal stem cells via attenuation of reactive oxygen species and elevation of antioxidant enzymes
    Bahrampour Juybari K, Kamarul T, Najafi M, Jafari D, Sharifi AM
    Cell Tissue Res, 2018 08;373(2):407-419.
    PMID: 29582166 DOI: 10.1007/s00441-018-2825-y
    Strategies based on mesenchymal stem cell (MSC) therapy for restoring injured articular cartilage are not effective enough in osteoarthritis (OA). Due to the enhanced inflammation and oxidative stress in OA microenvironment, differentiation of MSCs into chondrocytes would be impaired. This study aims to explore the effects of diallyl disulfide (DADS) on IL-1β-mediated inflammation and oxidative stress in human adipose derived mesenchymal stem cells (hADSCs) during chondrogenesis. MTT assay was employed to examine the effects of various concentrations of DADS on the viability of hADSCs at different time scales to obtain non-cytotoxic concentration range of DADS. The effects of DADS on IL-1β-induced intracellular ROS generation and lipid peroxidation were evaluated in hADSCs. Western blotting was used to analyze the protein expression levels of IκBα (np), IκBα (p), NF-κB (np) and NF-κB (p). Furthermore, the gene expression levels of antioxidant enzymes in hADSCs and chondrogenic markers at days 7, 14 and 21 of differentiation were measured using qRT-PCR. The results showed that addition of DADS significantly enhanced the mRNA expression levels of antioxidant enzymes as well as reduced ROS elevation, lipid peroxidation, IκBα activation and NF-κB nuclear translocation in hADSCs treated with IL-1β. In addition, DADS could significantly increase the expression levels of IL-1β-induced impaired chondrogenic marker genes in differentiated hADSCs. Treatment with DADS may provide an effective approach to prevent the pro-inflammatory cytokines and oxidative stress as catabolic causes of chondrocyte cell death and enhance the protective anabolic effects by promoting chondrogenesis associated gene expressions in hADSCs exposed to OA condition.
  3. Quantifying the ultrastructure changes of air-dried and irradiated human amniotic membrane using atomic force microscopy: a preliminary study
    Mohd S, Ghazali MI, Yusof N, Sulaiman S, Ramalingam S, Kamarul T, et al.
    Cell Tissue Bank, 2018 Dec;19(4):613-622.
    PMID: 30056604 DOI: 10.1007/s10561-018-9711-4
    Air-dried and sterilized amnion has been widely used as a dressing to treat burn and partial thickness wounds. Sterilisation at the standard dose of 25 kGy was reported to cause changes in the morphological structure as observed under the scanning electron microscope. This study aimed to quantify the changes in the ultrastructure of the air-dried amnion after gamma-irradiated at several doses by using atomic force microscope. Human placentae were retrieved from mothers who had undergone cesarean elective surgery. Amnion separated from chorion was processed and air-dried for 16 h. It was cut into 10 × 10 mm, individually packed and exposed to gamma irradiation at 5, 15, 25 and 35 kGy. Changes in the ultrastructural images of the amnion were quantified in term of diameter of the epithelial cells, size of the intercellular gap and membrane surface roughness. The longest diameter of the amnion cells reduced significantly after radiation (p 
  4. Fulltext COVID-19 in Singapore and Malaysia: Rising to the Challenges of Orthopaedic Practice in an Evolving Pandemic
    Tay K, Kamarul T, Lok WY, Mansor M, Li X, Wong J, et al.
    Malays Orthop J, 2020 Jul;14(2).
    PMID: 32313613 DOI: 10.5704/MOJ.2007.001
    With the increasing number of COVID-19 cases and related deaths worldwide, we decided to share the development of this condition in Singapore and Malaysia. First few cases were diagnosed in the two countries at the end of January 2020, and the numbers have surged to thousands by end of March 2020. We will focus on strategies adopted by the government and also the Orthopaedic community of the two countries up till the beginning of April 2020. We hope that by sharing of relevant information and knowledge on how we are managing the COVID-19 condition, we can help other communities, and health care workers to more effectively overcome this pandemic.
  5. Chondrocyte-alginate constructs with or without TGF-β1 produces superior extracellular matrix expression than monolayer cultures
    Ab-Rahim S, Selvaratnam L, Raghavendran HR, Kamarul T
    Mol Cell Biochem, 2013 Apr;376(1-2):11-20.
    PMID: 23238871 DOI: 10.1007/s11010-012-1543-0
    Tissue engineering approaches often require expansion of cell numbers in vitro to accelerate tissue regenerative processes. Although several studies have used this technique for therapeutic purposes, a major concern involving the use of isolated chondrocyte culture is the reduction of extracellular matrix (ECM) protein expressed due to the transfer of cells from the normal physiological milieu to the artificial 2D environment provided by the cell culture flasks. To overcome this issue, the use of alginate hydrogel beads as a substrate in chondrocyte cultures has been suggested. However, the resultant characteristics of cells embedded in this bead is elusive. To elucidate this, a study using chondrocytes isolated from rabbit knee articular cartilage expanded in vitro as monolayer and chondrocyte-alginate constructs was conducted. Immunohistochemical evaluation and ECM distribution was examined with or without transforming growth factor (TGF-β1) supplement to determine the ability of cells to express major chondrogenic proteins in these environments. Histological examination followed by transmission electron microscopy and scanning electron microscopy was performed to determine the morphology and the ultrastructural characteristics of these cells. Results demonstrated a significant increase in glycosaminoglycan/mg protein levels in chondrocyte cultures grown in alginate construct than in monolayer cultures. In addition, an abundance of ECM protein distribution surrounding chondrocytes cultured in alginate hydrogel was observed. In conclusion, the current study demonstrates that the use of alginate hydrogel beads in chondrocyte cultures with or without TGF-β1 supplement provided superior ECM expression than monolayer cultures.
  6. Dual l-Carnosine/Aloe vera Nanophytosomes with Synergistically Enhanced Protective Effects against Methylglyoxal-Induced Angiogenesis Impairment
    Darvishi B, Dinarvand R, Mohammadpour H, Kamarul T, Sharifi AM
    Mol Pharm, 2021 09 06;18(9):3302-3325.
    PMID: 34297586 DOI: 10.1021/acs.molpharmaceut.1c00248
    Microvascular complications are among the major outcomes of patients with type II diabetes mellitus, which are the consequences of impaired physiological functioning of small blood vessels and angiogenic responses in these patients. Overproduction and accumulation of methylglyoxal (MGO), a highly reactive dicarbonyl byproduct of glycolysis pathway, has been acclaimed as the main inducer of impaired angiogenic responses and microvascular dysfunction in diabetic patients with uncontrolled hyperglycemia. Hence, an effective approach to overcome diabetes-associated microvascular complications is to neutralize the deleterious activity of enhanced the concentration of MGO in the body. Owing to the glycation inhibitory activity of Aloe vera whole extract, and capability of l-carnosine, an endogenous dipeptide, in attenuating MGO's destructive activity, we examined whether application of a combination of l-carnosine and A. vera could be an effective way of synergistically weakening this reactive dicarbonyl's impaired angiogenic effects. Additionally, overcoming the poor cellular uptake and internalization of l-carnosine and A. vera, a nanophytosomal formulation of the physical mixture of two compounds was also established. Although l-carnosine and A. vera at whole studied combination ratios could synergistically enhance viability of human umbilical vein endothelial cells (HUVECs) treated with MGO, the 25:1 w/w ratio was the most effective one among the others (27 ± 0.5% compared to 12 ± 0.3 to 18 ± 0.4%; F (4, 15) = 183.9, P < 0.0001). Developing dual nanophytosomes of l-carnosine/A. vera (25:1) combination ratio, we demonstrated superiority of the nanophytosomal formulation in protecting HUVECs against MGO-induced toxicity following a 24-72 h incubation period (17.3, 15.8, and 12.4% respectively). Moreover, 500 μg/mL concentration of dual l-carnosine/A. vera nanophytosomes exhibited a superior free radical scavenging potency (63 ± 4 RFU vs 83 ± 5 RFU; F (5, 12) = 54.81, P < 0.0001) and nitric oxide synthesizing capacity (26.11 ± 0.19 vs 5.1 ± 0.33; F (5, 12) = 2537, P < 0.0001) compared to their physical combination counterpart. Similarly, 500 μg/mL dual l-carnosine/A. vera nanophytosome-treated HUVECs demonstrated a superior tube formation capacity (15 ± 3 vs 2 ± 0.3; F (5, 12) = 30.87, P < 0.001), wound scratch healing capability (4.92 ± 0.3 vs 3.07 ± 0.3 mm/h; F (5, 12) = 39.21, P < 0.0001), and transwell migration (586 ± 32 vs 394 ± 18; F (5, 12) = 231.8, P < 0.001) and invasion (172 ± 9 vs 115 ± 5; F (5, 12) = 581.1, P < 0.0001) activities compared to the physical combination treated ones. Further confirming the proangiogenic activity of the dual l-carnosine/A. vera nanophytosomes, a significant shift toward expression of proangiogenic genes including HIF-1α, VEGFA, bFGF, KDR, and Ang II was reported in treated HUVECs. Overall, dual l-carnosine/A. vera nanophytosomes could be a potential candidate for attenuating type II DM-associated microvascular complications with an impaired angiogenesis background.
  7. Platelet rich concentrate enhances mesenchymal stem cells capacity to repair focal cartilage injury in rabbits
    Samuel S, Ahmad RE, Ramasamy TS, Manan F, Kamarul T
    Injury, 2018 Apr;49(4):775-783.
    PMID: 29503013 DOI: 10.1016/j.injury.2018.02.020
    BACKGROUND: It has been previously suggested that the use of regenerative promoters, which include bone marrow-derived mesenchymal stem cells (MSCs) or natural growth factors supplement such as platelet-rich concentrate (PRC) could promote cartilage regeneration. However, the notion that the concurrent use of both promoters may provide a synergistic effect that improves the repair outcome of focal cartilage injury has not been previously demonstrated. This study was thus conducted to determine whether the concomitant use of PRC could further enhance the reparative potential of MSCs encapsulated in alginate transplanted into focal cartilage injury in rabbits.

    METHODS: Artifically created full thickness cartilage defects were made on the weight-bearing region of medial femoral condyles in bilateral knees of New Zealand White rabbits (N = 30). After one month, the right knee was treated with either i) PRC (n = 10), ii) MSCs (n = 10), or, iii) a combination of PRC and MSCs (PRC + MSC) (n = 10), all encapsulated in alginate. The left knee remained untreated (control). Rabbits were sacrificed at 3 and 6 months after treatment. Cartilage tissue regeneration was accessed using ICRS morphologic scoring, histologic grading by O'Driscoll scoring, immunohistochemical staining and quantitative analysis of glycosaminoglycans (GAG) per total protein content.

    RESULTS: At 3 months, transplantation using PRC alone was equally effective as MSCs in inducing the repair of cartilage defects. However, PRC + MSC resulted in significantly higher ICRS and O'Driscoll scores (p 

  8. High-fat diet- and angiotensin II-induced aneurysm concurrently elicits splenic hypertrophy
    Gopal K, Nagarajan P, Shankar EM, Kamarul T, Kumar JM
    Eur J Clin Invest, 2014 Dec;44(12):1169-76.
    PMID: 25315426 DOI: 10.1111/eci.12351
    Angiotensin II (Ang II) and high-fat diet are implicated in causing pathological changes in the vascular endothelium, brain, kidney and liver. The association of aneurysm leading to histopathological changes in the splenic compartment remains elusive. Further, the salubrious credentials of antioxidants, especially α-tocopherol and β-carotene in the resolution of splenic pathology have not been investigated.
  9. Finite element analysis of three commonly used external fixation devices for treating Type III pilon fractures
    Ramlee MH, Kadir MR, Murali MR, Kamarul T
    Med Eng Phys, 2014 Oct;36(10):1322-30.
    PMID: 25127377 DOI: 10.1016/j.medengphy.2014.05.015
    Pilon fractures are commonly caused by high energy trauma and can result in long-term immobilization of patients. The use of an external fixator i.e. the (1) Delta, (2) Mitkovic or (3) Unilateral frame for treating type III pilon fractures is generally recommended by many experts owing to the stability provided by these constructs. This allows this type of fracture to heal quickly whilst permitting early mobilization. However, the stability of one fixator over the other has not been previously demonstrated. This study was conducted to determine the biomechanical stability of these external fixators in type III pilon fractures using finite element modelling. Three-dimensional models of the tibia, fibula, talus, calcaneus, navicular, cuboid, three cuneiforms and five metatarsal bones were reconstructed from previously obtained CT datasets. Bones were assigned with isotropic material properties, while the cartilage was assigned as hyperelastic springs with Mooney-Rivlin properties. Axial loads of 350 N and 70 N were applied at the tibia to simulate the stance and the swing phase of a gait cycle. To prevent rigid body motion, the calcaneus and metatarsals were fixed distally in all degrees of freedom. The results indicate that the model with the Delta frame produced the lowest relative micromovement (0.03 mm) compared to the Mitkovic (0.05 mm) and Unilateral (0.42 mm) fixators during the stance phase. The highest stress concentrations were found at the pin of the Unilateral external fixator (509.2 MPa) compared to the Mitkovic (286.0 MPa) and the Delta (266.7 MPa) frames. In conclusion, the Delta external fixator was found to be the most stable external fixator for treating type III pilon fractures.
  10. Biomechanical evaluation of two commonly used external fixators in the treatment of open subtalar dislocation--a finite element analysis
    Ramlee MH, Kadir MR, Murali MR, Kamarul T
    Med Eng Phys, 2014 Oct;36(10):1358-66.
    PMID: 25092623 DOI: 10.1016/j.medengphy.2014.07.001
    Subtalar dislocation is a rare injury caused by high-energy trauma. Current treatment strategies include leg casts, internal fixation and external fixation. Among these, external fixators are the most commonly used as this method is believed to provide better stabilization. However, the biomechanical stability provided by these fixators has not been demonstrated. This biomechanical study compares two commonly used external fixators, i.e. Mitkovic and Delta. CT imaging data were used to reconstruct three-dimensional models of the tibia, fibula, talus, calcaneus, navicular, cuboid, three cuneiforms and five metatarsal bones. The 3D models of the bones and cartilages were then converted into four-noded linear tetrahedral elements, whilst the ligaments were modelled with linear spring elements. Bones and cartilage were idealized as homogeneous, isotropic and linear. To simulate loading during walking, axial loading (70 N during the swing and 350 N during the stance phase) was applied at the end of diaphyseal tibia. The results demonstrate that the Mitkovic fixator produced greater displacement (peak 3.0mm and 15.6mm) compared to the Delta fixator (peak 0.8mm and 3.9 mm), in both the swing and stance phase, respectively. This study demonstrates that the Delta external fixator provides superior stability over the Mitkovic fixator. The Delta fixator may be more effective in treating subtalar dislocation.
  11. Mechanical and functional assessment of the wrist affected by rheumatoid arthritis: A finite element analysis
    Bajuri MN, Kadir MR, Raman MM, Kamarul T
    Med Eng Phys, 2012 Nov;34(9):1294-302.
    PMID: 22277308 DOI: 10.1016/j.medengphy.2011.12.020
    Understanding the pathomechanics involved in rheumatoid arthritis (RA) of the wrist provides valuable information, which will invariably allow various therapeutic possibilities to be explored. The computational modelling of this disease permits the appropriate simulation to be conducted seamlessly. A study that underpins the fundamental concept that produces the biomechanical changes in a rheumatoid wrist was thus conducted through the use of finite element method. The RA model was constructed from computed tomography datasets, taking into account three major characteristics: synovial proliferation, cartilage destruction and ligamentous laxity. As control, a healthy wrist joint model was developed in parallel and compared. Cartilage was modelled based on the shape of the articulation while the ligaments were modelled with linear spring elements. A load-controlled analysis was performed simulating physiological hand grip loading conditions. The results demonstrated that the diseased model produced abnormal wrist extension and stress distribution as compared to the healthy wrist model. Due to the weakening of the ligaments, destruction of the cartilage and lower bone density, the altered biomechanical stresses were particularly evident at the radioscaphoid and capitolunate articulations which correlate to clinical findings. These results demonstrate the robust finding of the developed RA wrist model, which accurately predicted the pathological process.
  12. Evaluating the Protective Effects and Mechanisms of Diallyl Disulfide on Interlukin-1β-Induced Oxidative Stress and Mitochondrial Apoptotic Signaling Pathways in Cultured Chondrocytes
    Hosseinzadeh A, Jafari D, Kamarul T, Bagheri A, Sharifi AM
    J Cell Biochem, 2017 Jul;118(7):1879-1888.
    PMID: 28169456 DOI: 10.1002/jcb.25907
    The protective effects and mechanisms of DADS on IL-1β-mediated oxidative stress and mitochondrial apoptosis were investigated in C28I2 human chondrocytes. The effect of various concentrations of DADS (1, 5 10, 25, 50, and 100 μM) on C28I2 cell viability was evaluated in different times (2, 4, 8, 16, and 24 h) to obtain the non-cytotoxic concentrations of drug by MTT-assay. The protective effect of non-toxic concentrations of DADS on experimentally induced oxidative stress and apoptosis by IL-1β in C28I2 was evaluated. The effects of DADS on IL-1β-induced intracellular ROS production and lipid peroxidation were detected and the proteins expression of Nrf2, Bax, Bcl-2, caspase-3, total and phosphorylated JNK, and P38 MAPKs were analyzed by Western blotting. The mRNA expression of detoxifying phase II/antioxidant enzymes including heme oxygenase-1, NAD(P)H quinine oxidoreductase, glutathione S-transferase-P1, catalase, superoxide dismutase-1, glutathione peroxidase-1, -3, -4 were evaluated by reverse transcription-polymerase chain reaction. DADS in 1, 5, 10, and 25 μM concentrations had no cytotoxic effect after 24 h. Pretreatment with DADS remarkably increased Nrf2 nuclear translocation as well as the genes expression of detoxifying phase II/antioxidant enzymes and reduced IL-1β-induced elevation of ROS, lipid peroxidation, Bax/Bcl-2 ratio, caspase-3 activation, and JNK and P38 phosphorylation. DADS could considerably reduce IL-1β-induced oxidative stress and consequent mitochondrial apoptosis, as the major mechanisms of chondrocyte cell death in an experimental model of osteoarthritis. It may be considered as natural product in protecting OA-induced cartilage damage in clinical setting. J. Cell. Biochem. 118: 1879-1888, 2017. © 2017 Wiley Periodicals, Inc.
  13. Fulltext Change in facial shape in two cohorts of Japanese adult female students twenty years apart
    Hossain MG, Saw A, Ohtsuki F, Lestrel PE, Kamarul T
    Singapore Med J, 2011 Nov;52(11):818-23.
    PMID: 22173252
    Secular changes in the head and body dimensions of the Japanese population were recorded during the last century, but studies on Japanese adult facial shape were poorly documented. This study aimed to document the secular changes in facial shape and their association with craniofacial measures of Japanese adult female students.
  14. Fulltext Multiple regression analysis of anthropometric measurements influencing the cephalic index of male Japanese university students
    Hossain MG, Saw A, Alam R, Ohtsuki F, Kamarul T
    Singapore Med J, 2013 Sep;54(9):516-20.
    PMID: 24068061
    INTRODUCTION: Cephalic index (CI), the ratio of head breadth to head length, is widely used to categorise human populations. The aim of this study was to access the impact of anthropometric measurements on the CI of male Japanese university students.

    METHODS: This study included 1,215 male university students from Tokyo and Kyoto, selected using convenient sampling. Multiple regression analysis was used to determine the effect of anthropometric measurements on CI.

    RESULTS: The variance inflation factor (VIF) showed no evidence of a multicollinearity problem among independent variables. The coefficients of the regression line demonstrated a significant positive relationship between CI and minimum frontal breadth (p < 0.01), bizygomatic breadth (p < 0.01) and head height (p < 0.05), and a negative relationship between CI and morphological facial height (p < 0.01) and head circumference (p < 0.01). Moreover, the coefficient and odds ratio of logistic regression analysis showed a greater likelihood for minimum frontal breadth (p < 0.01) and bizygomatic breadth (p < 0.01) to predict round-headedness, and morphological facial height (p < 0.05) and head circumference (p < 0.01) to predict long-headedness. Stepwise regression analysis revealed bizygomatic breadth, head circumference, minimum frontal breadth, head height and morphological facial height to be the best predictor craniofacial measurements with respect to CI.

    CONCLUSION: The results suggest that most of the variables considered in this study appear to influence the CI of adult male Japanese students.
  15. Hyaluronic acid with or without bone marrow derived-mesenchymal stem cells improves osteoarthritic knee changes in rat model: a preliminary report
    Suhaeb AM, Naveen S, Mansor A, Kamarul T
    Indian J Exp Biol, 2012 Jun;50(6):383-90.
    PMID: 22734248
    Despite being a complex degenerative joint disease, studies on osteoarthritis (OA) suggest that its progression can be reduced by the use of hyaluronic acid (HA) or mesenchymal stem cells (MSC). The present study thus aims to examine the effects of MSC, HA and the combination of HA-MSC in treating OA in rat model. The histological observations using O'Driscoll score indicate that it is the use of HA and MSC independently and not their combination that delays the progression of OA. In conclusion, the preliminary study suggest that the use of either HA or MSCs effectively reduces OA progression better than their combined use.
  16. Synergistic interaction of platelet derived growth factor (PDGF) with the surface of PLLA/Col/HA and PLLA/HA scaffolds produces rapid osteogenic differentiation
    Raghavendran HR, Mohan S, Genasan K, Murali MR, Naveen SV, Talebian S, et al.
    Colloids Surf B Biointerfaces, 2016 Mar 1;139:68-78.
    PMID: 26700235 DOI: 10.1016/j.colsurfb.2015.11.053
    Scaffolds with structural features similar to the extracellular matrix stimulate rapid osteogenic differentiation in favorable microenvironment and with growth factor supplementation. In this study, the osteogenic potential of electrospun poly-l-lactide/hydroxyapatite/collagen (PLLA/Col/HA, PLLA/HA and PLLA/Col) scaffolds were tested in vitro with the supplementation of platelet derived growth factor-BB (PDGF-BB). Cell attachment and topography, mineralization, extracellular matrix protein localization, and gene expression of the human mesenchymal stromal cells were compared between the fibrous scaffolds PLLA/Col/HA, PLLA/Col, and PLLA/HA. The levels of osteocalcin, calcium, and mineralization were significantly greater in the PLLA/Col/HA and PLLA/HA compared with PLLA/Col. High expression of fibronectin, intracellular adhesion molecule, cadherin, and collagen 1 (Col1) suggests that PLLA/Col/HA and PLLA/HA scaffolds had superior osteoinductivity than PLLA/Col. Additionally, osteopontin, osteocalcin, osterix, Runt-related transcription factor 2 (Runx2), and bone morphogenic protein (BMP2) expression were higher in PLLA/Col/HA and PLLA/HA compared with PLLA/Col. In comparison with PLLA/Col, the PLLA/Col/HA and PLLA/HA scaffolds presented a significant upregulation of the genes Runx2, Col 1, Integrin, osteonectin (ON), bone gamma-carboxyglutamic acid-containing protein (BGALP), osteopontin (OPN), and BMP2. The upregulation of these genes was further increased with PDGF-BB supplementation. These results show that PDGF-BB acts synergistically with PLLA/Col/HA and PLLA/HA to enhance the osteogenic differentiation potential. Therefore, this combination can be used for the rapid expansion of bone marrow stromal cells into bone-forming cells for tissue engineering.
  17. Fulltext Attrition of Hepatic Damage Inflicted by Angiotensin II with α-Tocopherol and β-Carotene in Experimental Apolipoprotein E Knock-out Mice
    Gopal K, Gowtham M, Sachin S, Ravishankar Ram M, Shankar EM, Kamarul T
    Sci Rep, 2015 Dec 16;5:18300.
    PMID: 26670291 DOI: 10.1038/srep18300
    Angiotensin II is one of the key regulatory peptides implicated in the pathogenesis of liver disease. The mechanisms underlying the salubrious role of α-tocopherol and β-carotene on liver pathology have not been comprehensively assessed. Here, we investigated the mechanisms underlying the role of Angiotensin II on hepatic damage and if α-tocopherol and β-carotene supplementation attenuates hepatic damage. Hepatic damage was induced in Apoe(-/-)mice by infusion of Angiotensin II followed by oral administration with α-tocopherol and β-carotene-enriched diet for 60 days. Investigations showed fibrosis, kupffer cell hyperplasia, hepatocyte degeneration and hepatic cell apoptosis; sinusoidal dilatation along with haemorrhages; evidence of fluid accumulation; increased ROS level and increased AST and ALT activities. In addition, tPA and uPA were down-regulated due to 42-fold up-regulation of PAI-1. MMP-2, MMP-9, MMP-12, and M-CSF were down-regulated in Angiotensin II-treated animals. Notably, α-tocopherol and β-carotene treatment controlled ROS, fibrosis, hepatocyte degeneration, kupffer cell hyperplasia, hepatocyte apoptosis, sinusoidal dilatation and fluid accumulation in the liver sinusoids, and liver enzyme levels. In addition, PAI-1, tPA and uPA expressions were markedly controlled by β-carotene treatment. Thus, Angiotensin II markedly influenced hepatic damage possibly by restraining fibrinolytic system. We concluded that α-tocopherol and β-carotene treatment has salubrious role in repairing hepatic pathology.
  18. Effect of 17β-estradiol on mediators involved in mesenchymal stromal cell trafficking in cell therapy of diabetes
    Mirzamohammadi S, Aali E, Najafi R, Kamarul T, Mehrabani M, Aminzadeh A, et al.
    Cytotherapy, 2015 Jan;17(1):46-57.
    PMID: 25457279 DOI: 10.1016/j.jcyt.2014.06.009
    Mesenchymal stromal cells (MSCs) have shown great promise for cell therapy of a wide range of diseases such as diabetes. However, insufficient viability of transplanted cells reaching to damaged tissues has limited their potential therapeutic effects. Expression of estrogen receptors on stem cells may suggest a role for 17β-estradiol (E2) in regulating some functions in these cells. There is evidence that E2 enhances homing of stem cells. Induction of hypoxia-inducible factor-1α (HIF-1α) by E2 and the profound effect of HIF-1α on migration of cells have previously been demonstrated. We investigated the effect of E2 on major mediators involved in trafficking and subsequent homing of MSCs both in vitro and in vivo in diabetic rats.
  19. Fulltext Platelet rich concentrate promotes early cellular proliferation and multiple lineage differentiation of human mesenchymal stromal cells in vitro
    Shani S, Ahmad RE, Naveen SV, Murali MR, Puvanan K, Abbas AA, et al.
    ScientificWorldJournal, 2014;2014:845293.
    PMID: 25436230 DOI: 10.1155/2014/845293
    Platelet rich concentrate (PRC) is a natural adjuvant that aids in human mesenchymal stromal cell (hMSC) proliferation in vitro; however, its role requires further exploration. This study was conducted to determine the optimal concentration of PRC required for achieving the maximal proliferation, and the need for activating the platelets to achieve this effect, and if PRC could independently induce early differentiation of hMSC. The gene expression of markers for osteocytes (ALP, RUNX2), chondrocytes (SOX9, COL2A1), and adipocytes (PPAR-γ) was determined at each time point in hMSC treated with 15% activated and nonactivated PRC since maximal proliferative effect was achieved at this concentration. The isolated PRC had approximately fourfold higher platelet count than whole blood. There was no significant difference in hMSC proliferation between the activated and nonactivated PRC. Only RUNX2 and SOX9 genes were upregulated throughout the 8 days. However, protein expression study showed formation of oil globules from day 4, significant increase in ALP at days 6 and 8 (P ≤ 0.05), and increased glycosaminoglycan levels at all time points (P < 0.05), suggesting the early differentiation of hMSC into osteogenic and adipogenic lineages. This study demonstrates that the use of PRC increased hMSC proliferation and induced early differentiation of hMSC into multiple mesenchymal lineages, without preactivation or addition of differentiation medium.
  20. The proliferation and tenogenic differentiation potential of bone marrow-derived mesenchymal stromal cell are influenced by specific uniaxial cyclic tensile loading conditions
    Nam HY, Pingguan-Murphy B, Amir Abbas A, Mahmood Merican A, Kamarul T
    Biomech Model Mechanobiol, 2015 Jun;14(3):649-63.
    PMID: 25351891 DOI: 10.1007/s10237-014-0628-y
    It has been previously demonstrated that mechanical stimuli are important for multipotent human bone marrow-derived mesenchymal stromal cells (hMSCs) to maintain good tissue homeostasis and even to enhance tissue repair processes. In tendons, this is achieved by promoting the cellular proliferation and tenogenic expression/differentiation. The present study was conducted to determine the optimal loading conditions needed to achieve the best proliferation rates and tenogenic differentiation potential. The effects of mechanical uniaxial stretching using different rates and strains were performed on hMSCs cultured in vitro. hMSCs were subjected to cyclical uniaxial stretching of 4, 8 or 12 % strain at 0.5 or 1 Hz for 6, 24, 48 or 72 h. Cell proliferation was analyzed using alamarBlue[Formula: see text] assay, while hMSCs differentiation was analyzed using total collagen assay and specific tenogenic gene expression markers (type I collagen, type III collagen, decorin, tenascin-C, scleraxis and tenomodulin). Our results demonstrate that the highest cell proliferation is observed when 4 % strain [Formula: see text] 1 Hz was applied. However, at 8 % strain [Formula: see text] 1 Hz loading, collagen production and the tenogenic gene expression were highest. Increasing strain or rates thereafter did not demonstrate any significant increase in both cell proliferation and tenogenic differentiation. In conclusion, our results suggest that 4 % [Formula: see text] 1 Hz cyclic uniaxial loading increases cell proliferation, but higher strains are required for superior tenogenic expressions. This study suggests that selected loading regimes will stimulate tenogenesis of hMSCs.
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