Browsing by Author "Muhamed, J"

Now showing 1 - 7 of 7
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    Biocompatibility and 1.923 Immunophenotypic Characterization of a Porcine Cholecyst-derived Scaffold Implanted in Rats
    (Toxicol Pathol., 2015-02) Muhamed, J; Revi, D; Rajan, A; Geetha, S; Anilkumar, TV
    Comparative histomorphological assessment of local response to implanted reference biomaterial, also called biocompatibility testing/evaluation, in an appropriate animal model is a widely practiced safety evaluation procedure performed on biomaterials before clinical use. Standardized protocols and procedures, originally designed for testing synthetic materials, available for the testing/evaluation do not account for the immunogenic potential of a candidate biomaterial. Therefore, it is appropriate to supplement the routine biocompatibility test reports with adjunct data that may provide insight into the immunogenic potential of candidate biomaterials, especially when testing biomaterials that are derived from mammalian sources. This article presents expanded safety evaluation data of a porcine cholecyst–derived scaffold (CDS) intended as a xenogeneic graft. The biocompatibility was tested in rat subcutaneous model in comparison with a reference material and the CDS was found biocompatible. However, when studied by immunohistochemistry and real-time reverse transcription polymerase chain reaction for the number and/or polarization of M1 macrophage, M2 macrophage, cytotoxic T-cell, helper T cell, TH1 cell, and TH2 cell, the CDS appeared to induce a differential local immunopathological tissue reaction despite the similarity in biocompatibility with the reference material. The adjunct data collected were useful for objectively assessing the safety of CDS as a xenograft.
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    Biocompatibility and Immunophenotypic Characterization of a Porcine Cholecyst-derived Scaffold Implanted in Rats
    (TOXICOLOGIC PATHOLOGY, 2015) Muhamed, J; Revi, D; Rajan, A; Geetha, S; Anilkumar, TV
    Comparative histomorphological assessment of local response to implanted reference biomaterial, also called biocompatibility testing/evaluation, in an appropriate animal model is a widely practiced safety evaluation procedure performed on biomaterials before clinical use. Standardized protocols and procedures, originally designed for testing synthetic materials, available for the testing/evaluation do not account for the immunogenic potential of a candidate biomaterial. Therefore, it is appropriate to supplement the routine biocompatibility test reports with adjunct data that may provide insight into the immunogenic potential of candidate biomaterials, especially when testing biomaterials that are derived from mammalian sources. This article presents expanded safety evaluation data of a porcine cholecyst-derived scaffold (CDS) intended as a xenogeneic graft. The biocompatibility was tested in rat subcutaneous model in comparison with a reference material and the CDS was found biocompatible. However, when studied by immunohistochemistry and real-time reverse transcription polymerase chain reaction for the number and/or polarization of M1 macrophage, M2 macrophage, cytotoxic T-cell, helper T cell, TH1 cell, and TH2 cell, the CDS appeared to induce a differential local immunopathological tissue reaction despite the similarity in biocompatibility with the reference material. The adjunct data collected were useful for objectively assessing the safety of CDS as a xenograft.
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    Biomaterial properties of cholecyst-derived scaffold recovered by a non-detergent/enzymatic method
    (JOURNAL OF BIOMEDICAL MATERIALS RESEARCH PART B-APPLIED BIOMATERIALS, 2014) Anilkumar, TV; Vineetha, VP; Revi, D; Muhamed, J; Rajan, A
    Isolation procedures for the recovery of extracellular matrices (ECMs) from animal organs/tissues that are useful in regenerative medicine involve multiple sequential steps/stages including collection of the source organ at slaughter, their transportation to laboratory, decellularization, decontamination, stabilization, and sterilization. Most of these steps require extensive use of chemicals/reagents/enzymes which may also adversely affect the quality of the scaffold. With an effort to minimize the use of chemicals/reagents/enzymes, while extracting biomaterial-grade ECM from porcine cholecyst (gall bladder), we performed preisolation ex situ incubation of the organ in a stabilizing agent that also caused in situ crosslinking of tissue-components and delaminated the collagen-rich ECM from the tissue-layer beneath the mucosa. The physical, chemical, and biological properties of the isolated scaffolds were similar to that of a commercially available porcine small intestinal submucosa. The cholecyst-derived scaffold not only satisfied preclinical safety-test procedures such as cytotoxicity, local response, and endotoxin load but also showed the potential to promote healing of full-thickness skin wound in a rabbit model. The procedure was also suitable for isolating scaffolds from other hollow organs such as jejunum and urinary bladder. It was concluded that enzyme/detergent treatment may be an avoidable step while isolating biomaterial-grade scaffolds from hollow organs. (C) 2014 Wiley Periodicals, Inc.
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    Comparative local immunogenic potential of scaffolds prepared from porcine cholecyst, jejunum, and urinary bladder in rat subcutaneous model
    (JOURNAL OF BIOMEDICAL MATERIALS RESEARCH PART B-APPLIED BIOMATERIALS, 2015) Muhamed, J; Revi, D; Rajan, A; Anilkumar, TV
    Extracellular matrices isolated from several mammalian organs/tissues have found several clinical uses as xenografts or implants. However, they may cause complications because of adverse immunologic reactions. Scaffolds that promote favorable graft-acceptance reaction are preferred for fabricating xenografts. The objective of this study was to evaluate the immunogenic potential of a porcine cholecyst-derived scaffold (CDS), prepared by a non-detergent/enzymatic method, in comparison with jejunum and urinary bladder-derived scaffolds in a rat subcutaneous model. Key graft-rejection/acceptance reaction was evaluated at the site of implantation by studying the occurrence and/or function of immunocompetent cells in the tissue reaction. There was differential occurrence of M1-macrophage, M2-macrophage, T-helper cells, T-cytotoxic cells, B-cells, and mast cells in the tissue reaction and the CDS attracted few cells compared with other scaffolds. Real-time polymerase chain reaction for evaluating mRNA of functional markers like inducible nitric oxide synthase (M1 macrophage), arginase 1 (M2 macrophage), interferon gamma (TH1 lymphocytes), and interlukin-4 (TH2 lymphocytes) suggested that the CDS, compared with the scaffolds prepared from small intestine and urinary bladder, elicited M2 macrophage and TH2 lymphocyte polarization that are congenial graft-acceptance reactions. The results indicated that CDS has less immunogenic potential compared with the scaffolds prepared from jejunum and urinary bladder when used as subcutaneous graft in rats. It was concluded that CDS is a promising animal-derived xenograft for biomedical application. (c) 2014 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 103B: 1302-1311, 2015.
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    Phenotypic Modulation of Cell Types around Implanted Polyethylene Terephthalate Fabric in Rabbit Muscle
    (TOXICOLOGIC PATHOLOGY, 2013) Muhamed, J; Revi, D; Joseph, R; Anilkumar, T
    Whereas the nature of healing reaction in skeletal muscle following implantation of biomaterial has been extensively studied, the extent of variation in cell phenotypes is poorly known. Here, we studied the phenotypic alteration of cell types following injury in skeletal muscle of rabbits implanted with a commonly used biomaterial, polyethylene terephthalate (PET) fabric. Following implantation, histomorphological features were studied after 1, 4, and 12 weeks. Routine objective histomorphological evaluation was supplemented with histochemistry for collagen and immunohistochemistry for proliferating cell nuclear antigen (PCNA), CD34, vimentin, and alpha smooth muscle actin (alpha-SMA). The extent of reaction was quantified. The foreign body giant cells were found to comprise subpopulations, based on the variation in vimentin detectability or the presence of differentially capable proliferating nuclei (PCNA positive). Many rhabdomyocytes adjacent to the implant were PCNA-positive and some of them showed CD34 positivity. Often, the rhabdomyocytes very near to implanted PET fabric assumed a myofibroblast phenotype as evidenced by vimentin and/or alpha-SMA positivity at immunohistochemistry. Overall, the results suggested a phenotypic alteration of native cell types following implantation of PET fabric in rabbit skeletal muscle. Quantification of such cell types at the tissue-material interphase in relation to the deposition of collagen may be desirable during safety evaluation of biomaterials by histomorphology.
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    Wound healing potential of scaffolds prepared from porcine jejunum and urinary bladder by a non-detergent/enzymatic method
    (JOURNAL OF BIOMATERIALS APPLICATIONS, 2015) Revi, D; Vineetha, VP; Muhamed, J; Surendran, GC; Rajan, A; Kumary, TV; Anilkumar, TV
    Scaffolds prepared using extracellular matrices of mammalian organs/tissues, when used as grafts, have wound healing potential. This paper evaluated the physical properties and invivo wound healing potential of jejunum-derived scaffold (JDS) and urinary bladder-derived scaffold (UDS) of porcine origin prepared by a non-detergent/enzymatic method. The former had higher flexural rigidity and suture retention strength compared to the latter, but both of them had the essential flexural rigidity and suture retention strength required for skin grafts. Full thickness skin-wounds on rabbit dorsum were treated with these scaffolds and the wound healing ability was compared by studying histomorphology parameters such as re-epithelialisation, collagen deposition, angiogenesis, proliferation of cells, mesenchymal cell infiltration and myofibroblast response. The extent of these reactions was assessed using histomorphometry. The results indicated that both grafts initiated healing faster than those wounds without any graft, as evidenced by the extent of cell proliferation and mesenchymal cell infiltration. The myofibroblast response persisted longer in the non-graft assisted wound healing reaction compared to the healing in the graft assisted wounds. Moreover, the JDS induced higher cell proliferation and greater angiogenesis than UDS probably indicating better healing by the former. The results suggested that JDS and UDS prepared by non-detergent/enzymatic method have potential clinical applications.
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    Wound healing potential of scaffolds prepared from porcine jejunum and urinary bladder by a non-detergent/enzymatic method.
    (J Biomater Appl., 2015-02) Revi, D; Vineetha, VP; Muhamed, J; Surendran, GC; Rajan, A; Kumary, TV; Anilkumar, TV
    Scaffolds prepared using extracellular matrices of mammalian organs/tissues, when used as grafts, have wound healing potential. This paper evaluated the physical properties and in vivo wound healing potential of jejunum-derived scaffold (JDS) and urinary bladder-derived scaffold (UDS) of porcine origin prepared by a non-detergent/enzymatic method. The former had higher flexural rigidity and suture retention strength compared to the latter, but both of them had the essential flexural rigidity and suture retention strength required for skin grafts. Full thickness skin-wounds on rabbit dorsum were treated with these scaffolds and the wound healing ability was compared by studying histomorphology parameters such as re-epithelialisation, collagen deposition, angiogenesis, proliferation of cells, mesenchymal cell infiltration and myofibroblast response. The extent of these reactions was assessed using histomorphometry. The results indicated that both grafts initiated healing faster than those wounds without any graft, as evidenced by the extent of cell proliferation and mesenchymal cell infiltration. The myofibroblast response persisted longer in the non-graft assisted wound healing reaction compared to the healing in the graft assisted wounds. Moreover, the JDS induced higher cell proliferation and greater angiogenesis than UDS probably indicating better healing by the former. The results suggested that JDS and UDS prepared by non-detergent/enzymatic method have potential clinical applications.