| Porcine induced pluripotent stem cells may bridge the gap between mouse and human iPS.
January 27, 2010 at 9:44 AM
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| | Porcine induced pluripotent stem cells may bridge the gap between mouse and human iPS. IUBMB Life. 2010 Jan 25; Authors: Esteban MA, Peng M, Deli Z, Cai J, Yang J, Xu J, Lai L, Pei D Recently, three independent laboratories reported the generation of induced pluripotent stem cells (iPSCs) from pig (Sus scrofa). This finding sums to the growing list of species (mouse, human, monkey, and rat, in this order) for which successful reprogramming using exogenous factors has been achieved, and multiple others are possibly forthcoming. But apart from demonstrating the universality of the network identified by Shinya Yamanaka, what makes the porcine model so special? On one side, pigs are an agricultural commodity and have an easy and affordable maintenance compared with nonhuman primates that normally need to be imported. On the other side, resemblance (for example, size of organs) of porcine and human physiology is striking and because pigs are a regular source of food the ethical concerns that still remain in monkeys are not applicable. Besides, the prolonged lifespan of pigs compared with other domestic species can allow exhaustive follow up of side! effects after transplantation. Porcine iPSCs may thus fill the gap between the mouse model, which due to its ease is preferred for mechanistic studies, and the first clinical trials using iPSCs in humans. However, although these studies are relevant and have created significant interest they face analogous problems that we discuss herein together with potential new directions. (c) 2010 IUBMB IUBMB Life, 2010. PMID: 20101630 [PubMed - as supplied by publisher] | | |
| Transfection efficiency of depolymerized chitosan and epidermal growth factor conjugated to chitosan-DNA polyplexes.
January 27, 2010 at 9:44 AM
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| | Transfection efficiency of depolymerized chitosan and epidermal growth factor conjugated to chitosan-DNA polyplexes. J Mater Sci Mater Med. 2010 Jan 26; Authors: Supaprutsakul S, Chotigeat W, Wanichpakorn S, Kedjarune-Leggat U An efficient non-viral gene delivery for varieties of cells has been considered essential for gene therapy and tissue engineering. This study evaluated transfection efficiency of chitosan (HW) with molecular weights (Mw) at 470 and degree of deacetylation (DDA) 80% and its depolymerization product (LW) with Mw at 16 kDa and DDA 54%, as well as epidermal growth factor (EGF) conjugated to chitosan-DNA microparticles of both HW and LW by using either disulfide linkage or NHS-PEO(4)-Maleimide as a cross linker. The results revealed that the depolymerized LW at chitosan/DNA charge ratio 56:1 and pH 6.9 gave high transfection efficiency in both KB, a cancer cell line, and fibroblast cells at about the same level of Lipofectamine(TM), but the EGF-conjugated chitosan-DNA polyplexes from these methods did not improve transfection efficiency, which may come from the aggregation and fusing of the complexes as shown in scanning electron microscopy. However, this depolymerized! LW chitosan showed the potential for further development as a safe and cost-effective non-viral gene delivery vehicle. PMID: 20101442 [PubMed - as supplied by publisher] | | |
| Electrospinning: A fascinating fiber fabrication technique.
January 27, 2010 at 9:44 AM
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| | Electrospinning: A fascinating fiber fabrication technique. Biotechnol Adv. 2010 Jan 22; Authors: Bhardwaj N, Kundu SC With the emergence of nanotechnology, researchers become more interested in studying the unique properties of nanoscale materials. Electrospinning, an electrostatic fiber fabrication technique has evinced more interest and attention in recent years due to its versatility and potential for applications in diverse fields. The notable applications include in tissue engineering, biosensors, filtration, wound dressings, drug delivery, and enzyme immobilization. The nanoscale fibers are generated by the application of strong electric field on polymer solution or melt. The non-wovens nanofibrous mats produced by this technique mimics extracellular matrix components much closely as compared to the conventional techniques. The sub-micron range spun fibers produced by this process, offer various advantages like high surface area to volume ratio, tunable porosity and the ability to manipulate nanofiber composition in order to get desired properties and function. Over the yea! rs, more than 200 polymers have been electropun for various applications and the number is still increasing gradually with time. With these in perspectives, we aim to present in this review, an overview of the electrospinning technique with its promising advantages and potential applications. We have discussed the electrospinning theory, spinnable polymers, parameters (solution and processing), which significantly affect the fiber morphology, solvent properties and melt electrospinning (alternative to solution electrospinning). Finally, we have focused on varied applications of electrospun fibers in different fields and concluded with the future prospects of this efficient technology. PMID: 20100560 [PubMed - as supplied by publisher] | | |
| Name of paper: p73alpha regulates the sensitivity of bone marrow mesenchymal stem cells to DNA damage agents.
January 27, 2010 at 9:44 AM
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| | Name of paper: p73alpha regulates the sensitivity of bone marrow mesenchymal stem cells to DNA damage agents. Toxicology. 2010 Jan 22; Authors: Liang W, Lu C, Li J, Yin JQ, Zhao RC Human bone marrow mesenchymal stem cells(MSCs)are important cell population located in bone marrow that are thought to have multiple functions in cell transplantation and gene therapy. Although in vitro experiments have demonstrated that hMSCs are resistant to apoptosis induction by DNA damage agents such as chemotherapeutic substances used in bone marrow transplantation, the molecular mechanism underlying remains unclear. p73 is highly similar to p53 and plays crucial roles in regulating DNA damage-induced apoptosis pathways. In this study, we investigated the role of p73alpha in response to chemotherapeutic substances in cultured human bone marrow MSCs. Cellular chemosensitivity and DNA damage-induced apoptotic cell death were examined in the hMSCs with exogenously over-expressed p73alpha. Our results showed that the expression of retrovirus-driven human p73alpha could be successfully induced in hMSCs, the over-expression of ectopic p73alpha resulted in a signif! icant increase of cellular sensitivity to cisplatin. The increase of cellular apoptosis was attributed to enhanced chemosentivity in p73alpha infected cells. Moreover, immunoblot analysis indicated that the co-activation of pro-apoptotic factors Bax and p21 were observed in the p73alpha insfected cells after cisplatin treatment. In conclusion, our findings suggested that p73alpha is an important determinant of cellular chemosensitivity in human bone marrow MSCs. PMID: 20100536 [PubMed - as supplied by publisher] | | |
| An improved, standardised protocol for the isolation, enrichment and targeted neural differentiation of Nestin+ progenitors from adult human dermis.
January 27, 2010 at 9:44 AM
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| | An improved, standardised protocol for the isolation, enrichment and targeted neural differentiation of Nestin+ progenitors from adult human dermis. Exp Dermatol. 2010 Jan 21; Authors: Ernst N, Tiede S, Tronnier V, Kruse C, Zechel C, Paus R Please cite this paper as: An improved, standardised protocol for the isolation, enrichment and targeted neural differentiation of Nestin+ progenitors from adult human dermis. Experimental Dermatology 2010. Abstract: Human skin-derived Nestin+ cells serve as a convenient source for autologous, adult, pluripotent progenitor cells that offer new therapeutic possibilities in cell-based regenerative medicine. However, the isolation of human Nestin+ cells has tended to be of very low efficiency and to produce highly variable cell yields. Here we report a standardised protocol that facilitates the isolation and enrichment of Nestin+ progenitor cells from enzymatically digested adult human scalp dermis. The use of distinct media like Dulbecco's modified Eagle medium supplemented with foetal bovine serum or, alternatively, serum-free, supplemented neural stem cell medium greatly affected cell morphology, proliferation and differentiation (e.g. towards a neural versus mese! nchymal phenotype). Finally, Nestin+ cells were isolated from a heterogeneous dermis-derived progenitor cell population, which proliferates within clones or floating microspheres under defined serum-free culture conditions. Supplementation of the medium with epidermal growth factor and basic fibroblast growth factor as well as coating with fibronectin allowed the highest enrichment level of Nestin+ progenitors and differentiation towards neural fate. These methodological advances should greatly facilitate the isolation, culture and targeted differentiation of primary, adult human scalp skin dermis-derived Nestin+ cells. PMID: 20100195 [PubMed - as supplied by publisher] | | |
| Pharmacologic Targeting of Endothelial Progenitor Cells.
January 27, 2010 at 9:44 AM
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| | Pharmacologic Targeting of Endothelial Progenitor Cells. Cardiovasc Hematol Disord Drug Targets. 2010 Jan 21; Authors: Albiero M, Menegazzo L, Avogaro A, Fadini GP The endothelium entered the field of regenerative medicine with the discovery of endothelial progenitor cells (EPCs). These cells participate in endothelial homeostasis and are actively involved in physiological and pathological neovascularization. Despite the unresolved discussion about the very phenotype of these cells, great efforts have been devoted to study the role of EPCs in cardiovascular diseases. EPCs are very rare in peripheral circulation and are further reduced in association with cardiovascular diseases. Therefore, finding therapies to improve EPCs could unleash the way to promising cell-based therapies. Ex-vivo expansion of EPCs is a critical step to augment EPCs number, but it still needs several improvements. An alternative strategy to partially overcome these limitations is to target EPCs with available drugs. In this review we will discuss how disparate pharmacological compounds have been used to improve EPCs number and functions. PMID: 20100167 [PubMed - as supplied by publisher] | | |
| Assessment of embryotoxicity of compounds in cosmetics by the embryonic stem cell test.
January 27, 2010 at 9:44 AM
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| | Assessment of embryotoxicity of compounds in cosmetics by the embryonic stem cell test. Toxicol Mech Methods. 2010 Jan 25; Authors: Chen R, Chen J, Cheng S, Qin J, Li W, Zhang L, Jiao H, Yu X, Zhang X, Lahn BT, Xiang AP The new EU legislations for cosmetics (Seventh Amendment) have laid down deadlines for the replacement of animal tests in cosmetics. This policy stimulates the acceptance of in vitro approaches to test embryotoxic potentials of compounds in cosmetics products. The embryonic stem cell test (EST) designed by The European Centre for the Validation of Alternative Methods (ECVAM) is currently the most promising in vitro assay to predict the embryotoxic potential of compounds. In this study, six selected compounds (hydroquinone, eugenol, dibutyl phthalate, antimony (III) oxide, neodymium (III) nitrate hydrate, melamine) formerly involved in cosmetic products were selected to test their embryotoxic potentials by the EST. 5-Fluorouracil and penicillin G were separately set as positive and negative control. The embryotoxic potential was determined by the prediction model (PM), which was calculated from three endpoints, the IC(50) 3T3, IC(50) ES, and ID(50). Hydroquinone, e! ugenol, and antimony (III) oxide indicated with strong embryotoxicity, while dibutyl phthalate, neodymium (III) nitrate hydrate, and melamine exhibited a weak embryotoxicity. These results may provide a valuable attempt to expand the application of EST to the cosmetics field. PMID: 20100057 [PubMed - as supplied by publisher] | | |
| Design and characterization of an injectable pericardial matrix gel: a potentially autologous scaffold for cardiac tissue engineering.
January 27, 2010 at 9:44 AM
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| | Design and characterization of an injectable pericardial matrix gel: a potentially autologous scaffold for cardiac tissue engineering. Tissue Eng Part A. 2010 Jan 25; Authors: Seif-Naraghi SB, Salvatore MA, Schup-Magoffin PJ, Hu DP, Christman KL Following ischemic injury in the heart, little to no repair occurs, causing a progressive degeneration of cardiac function that leads to congestive heart failure. Cardiac tissue engineering strategies have focused on designing a variety of injectable scaffolds that range in composition from single component materials to complex extracellular matrix-derived materials. In this study, the pericardial extracellular matrix, a commonly used biomaterial, was investigated for use as an injectable scaffold for cardiac repair. It was determined that a solubilized form of decellularized porcine pericardium could be injected and induced to gel in vivo, prompting investigation with human pericardium, which has the decided advantage of offering an autologous therapy. Characterization showed that the matrix gels retained components of the native pericardial extracellular matrix, with extant protein and glycosaminoglycan (GAG) content identified. The results of an in vitro migrat! ion assay indicate the porcine pericardial matrix is a stronger chemoattractant for relevant cell types, but in vivo results showed the two materials caused statistically similar amounts of neovascularization, demonstrating feasibility as injectable treatments. Potential stem cell mobilization was supported by the presence of c-Kit+ cells within the matrix injection regions. With this work, the pericardium is identified as a novel source for an autologous scaffold for treating myocardial infarction. PMID: 20100033 [PubMed - as supplied by publisher] | | |
| Current strategies and applications of tissue engineering in dentistry--a review part 1.
January 27, 2010 at 9:44 AM
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| | Current strategies and applications of tissue engineering in dentistry--a review part 1. Dent Update. 2009 Nov;36(9):577-9, 581-2 Authors: Malhotra N, Kundabala M, Acharya S A new direction in the field of vital pulp therapy is given by the introduction of tissue engineering as an emerging science. It aims to regenerate a functional tooth-tissue structure by the interplay of three basic key elements: stem cells, morphogens and scaffolds. It is a multidisciplinary approach that combines the principles of biology, medicine, and engineering to repair and/or regenerate a damaged tissue and/or organ. This two part article reviews and discusses the basic concept and strategies so far studied and researched for the engineering of basic dental tissues, to restore a functional tooth anatomy. This first part focuses on a detailed description of key elements used in tissue engineering and their applied clinical applications in dentistry. The second part will deal with the strategies that are being used and/or developed to regenerate the tooth tissues with the help of this scientific principle. CLINICAL RELEVANCE: The field of tissue engineering ! has recently shown promising results and a good prospect in dentistry for the development of the most ideal restorations to replace the lost tooth structure with a functional replacement. PMID: 20099610 [PubMed - in process] | | |
| Three-dimensional characterization of osteoclast bone-resorbing activity in the resorption lacunae.
January 27, 2010 at 9:44 AM
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| | Three-dimensional characterization of osteoclast bone-resorbing activity in the resorption lacunae. J Med Dent Sci. 2009 Sep;56(3):107-12 Authors: Soysa NS, Alles N, Aoki K, Ohya K Confocal laser microscopy is a well-recognized research tool in the fields of biological and material science which enables high-resolution images of samples with minimum requirements for specimen preparation. Here we introduce an innovative technique for the 3-D description and measurement of resorption pits using Super Depth Surface Profile Measurement Microscope based on the principle of confocal microscope. We show one example of culturing for 48 h with an established NF-kappaB inhibitor named NBD-peptide after plating mature osteoclasts on dentine slices with osteoblasts. The activity of osteoclasts is measured by determining the volume of resorbed portion of dentine by osteoclasts in vitro. The 3-D surface profile could be obtained by detecting the position at which the reflected laser intensity from the target becomes the maximum on z-axis. The volume and depth of resorption lacunae by stimulated osteoclasts is significantly increased compared to the un-sti! mulated group without changing of resorption area. The increase in volume and depth are dose-dependently inhibited by the NBD-peptide. Comparing to the classical method by measuring 2-D area of pits, analysis based on this technique could provide reliable quantitative assessment reflecting the osteoclast activity. PMID: 20099473 [PubMed - in process] | | |
| Tissue-engineered intrasynovial tendons: optimization of acellularization and seeding.
January 27, 2010 at 9:44 AM
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| | Tissue-engineered intrasynovial tendons: optimization of acellularization and seeding. J Rehabil Res Dev. 2009;46(4):489-98 Authors: Zhang AY, Bates SJ, Morrow E, Pham H, Pham B, Chang J The purpose of this research was to develop a tissue-engineered intrasynovial flexor tendon construct with the use of an acellularized flexor tendon scaffold repopulated with intrasynovial tendon cells. New Zealand white rabbit intrasynovial flexor tendons were acellularized by the following methods: high concentration NaCl + SDS, Trypsin/EDTA, Trypsin/EDTA + Triton X-100, Triton X-100, Triton X-100 + SDS, and freezing at -70 degrees C followed by Trypsin/EDTA + Triton X-100. Epitenon and endotenon cells were also isolated from rabbit intrasynovial tendons and expanded in culture. Acellularized tendon scaffolds were then reseeded with these cells. A subset of epitenon and endotenon cells was labeled with green and red fluorescent markers, respectively, to further characterize the preferred location of their attachment. Optimal acellularization was achieved by freezing at -70 degrees C followed by Trypsin/EDTA + Triton X-100. After reseeding, light microscopy of te! ndon constructs showed attachment of both epitenon and endotenon to the tendon scaffolds, with endotenon cells more likely to be found in the core of the scaffold. An intrasynovial tendon construct was developed with the use of acellularized intrasynovial tendons repopulated with intrasynovial tenocytes. These constructs grossly resemble normal intrasynovial tendons, and cells were found both on the surface and the core of the construct histologically. This new construct represents an important first step in developing a viable tissue-engineered flexor tendon. PMID: 19882484 [PubMed - indexed for MEDLINE] | | |
| Synergistic increase in osteosarcoma cell sensitivity to photodynamic therapy with aminolevulinic acid hexyl ester in the presence of hyperthermia.
January 27, 2010 at 9:44 AM
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| | Synergistic increase in osteosarcoma cell sensitivity to photodynamic therapy with aminolevulinic acid hexyl ester in the presence of hyperthermia. Photomed Laser Surg. 2009 Oct;27(5):791-7 Authors: Yanase S, Nomura J, Matsumura Y, Watanabe Y, Tagawa T OBJECTIVE: We observed that two osteosarcoma cell lines from the same tumor displayed marked differences in their sensitivities to photodynamic therapy (PDT) with aminolevulinic acid hexyl ester (hALA-PDT). We investigated why these two closely related lines had different hALA-PDT sensitivities and whether the PDT phototoxicity of the less sensitive cell line could be increased by a simultaneous application of hyperthermia (HT). METHODS: Flow cytometry was used to evaluate the intracellular accumulation of protoporphyrin IX (PpIX), a metabolic product of aminolevulinic acid, in two human mandibular osteosarcoma cell lines (HOSM-1 and HOSM-2) treated with HT, hALA-PDT, or hALA-PDT combined with HT (PDT + HT). With hALA-PDT, cells treated with 0.2 mM hALA were irradiated with a light dose of 10-80 J/cm(2) from a near-infrared irradiator. With PDT + HT, the cells were treated as for hALA-PDT except that the temperature was raised to 43.5 degrees C during irradiation.! RESULTS: At 6 h after hALA treatment, HOSM-2 cells carried about 1.53-fold more PpIX than HOSM-1 cells. With hALA-PDT, the survival rate for HOSM-1 cells treated with 80 J/cm(2) irradiation was 35.7%, while that for HOSM-2 cells treated with 40-80 J/cm(2) was below 12%. With PDT + HT, the survival rate for HOSM-1 and HOSM-2 cells treated with 80 J/cm(2) irradiation was 14.1% and 10.7%, respectively. CONCLUSION: A combination therapy comprising hALA-PDT + HT treatment may be very useful for the treatment of tumors containing cells that are insensitive to hALA-PDT, such as the HOSM-1 cell line described in this study. PMID: 19878029 [PubMed - indexed for MEDLINE] | | |
| Osteoblastic behavior of human bone marrow cells cultured over adsorbed collagen layer, over surface of collagen gels, and inside collagen gels.
January 27, 2010 at 9:44 AM
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| | Osteoblastic behavior of human bone marrow cells cultured over adsorbed collagen layer, over surface of collagen gels, and inside collagen gels. Connect Tissue Res. 2009;50(5):336-46 Authors: Fernandes LF, Costa MA, Fernandes MH, Tomás H While collagen type I is often used as a substrate for cell culturing and as a coating in biomedical implants, as far as we know a simple systematic study comparing the effects of the different presentations of collagen type I on the osteoblastic behavior of cells is missing. In this work, human bone marrow cells (hBMCs) were cultured under osteoblastic-inducing conditions, for 21 days, over a layer of adsorbed collagen (monomeric) and on the surface and inside collagen gels (fibrillar). Comparison was made based on three classical parameters; cell proliferation/viability, alkaline phosphatase (ALP) activity, and production of mineral deposits. The three types of collagen type I substrates allowed the adhesion, proliferation, and the osteoblastic differentiation of cells. However, hBMCs behavior was influenced by the monomeric/fibrillar and 2-/3-dimensional nature of the collagen substrates, namely: monomeric collagen favored cell attachment; cells on 2D substrate! s presented higher proliferation rates during the exponential phase of growth with formation of spiral-like multilayered structures; cells seeded inside 3D collagen gels formed a regular dense cellular mesh and had a low proliferating rate; cells cultured over or inside fibrillar collagen differentiated faster, with the 3D cultures presenting higher levels of ALP activity; and the extension of mineralization was greater for the cultures done over or inside fibrillar collagen. Thus, cells cultured over collagen gels showed both the ability for cell proliferation and for earlier differentiation, a fact that can be exploited in the biomaterials field. PMID: 19863393 [PubMed - indexed for MEDLINE] | | |
| Cell quality affects clinical outcome after MACI procedure for cartilage injury of the knee.
January 27, 2010 at 9:44 AM
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| | Cell quality affects clinical outcome after MACI procedure for cartilage injury of the knee. Knee Surg Sports Traumatol Arthrosc. 2009 Nov;17(11):1305-11 Authors: Pietschmann MF, Horng A, Niethammer T, Pagenstert I, Sievers B, Jansson V, Glaser C, Müller PE The aim of our study was to test the hypothesis that in early follow up after matrix guided autologous chondrocyte implantation (MACI), clinical results do not correlate with radiological and histological results, and that MACI as first line procedure and treatment of traumatic cartilage defects leads to better results compared to second line treatment and treatment of degenerative defects. Six and twelve months after MACI, patients IKDC-score was analysed, as well as the results of MRI-examinations. Specimens of the scaffold were histologically assessed at the time of implantation. The IKDC-score as well as the MRI-score improved significantly during follow up. The number of morphological abnormal cells was correlated with a poor clinical outcome. Defect aetiology proved to be a decisive factor for good clinical outcome. Patients with a short history of trauma (<1 year) and an osteochondritis dissecans were found to have better scores 1 year after MACI than pa! tients with a trauma more than 1 year ago. Defect-size, patients age and -gender did not significantly influence the clinical outcome. No differences were seen when MACI was used as first- or second-line procedure. Defect aetiology and quality of the cells are decisive for the clinical outcome. MACI can produce good and very good clinical results even when used as second-line procedure. PMID: 19513696 [PubMed - indexed for MEDLINE] | | |
| Novel nano-composite multi-layered biomaterial for the treatment of multifocal degenerative cartilage lesions.
January 27, 2010 at 9:44 AM
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| | Novel nano-composite multi-layered biomaterial for the treatment of multifocal degenerative cartilage lesions. Knee Surg Sports Traumatol Arthrosc. 2009 Nov;17(11):1312-5 Authors: Kon E, Delcogliano M, Filardo G, Altadonna G, Marcacci M We report on a 46-year-old athletic patient, previously treated with anterior cruciate ligament reconstruction, with large degenerative chondral lesions of the medial femoral condyle, trochlea and patella, which was successfully treated with a closing-wedge high tibial osteotomy and the implant of a newly developed biomimetic nanostructured osteochondral bioactive scaffold. After 1 year of follow-up the patient was pain-free, had full knee range of motion, and had returned to his pre-operation level of athletic activity. MRI evaluation at 6 months showed that the implant gave a hyaline-like signal as well as a good restoration of the articular surface, with minimal subchondral bone oedema. Subchondral oedema was almost non-visible at 12 months. PMID: 19468711 [PubMed - indexed for MEDLINE] | | |
| A novel implantation technique for engineered osteo-chondral grafts.
January 27, 2010 at 9:44 AM
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| | A novel implantation technique for engineered osteo-chondral grafts. Knee Surg Sports Traumatol Arthrosc. 2009 Nov;17(11):1377-83 Authors: Candrian C, Barbero A, Bonacina E, Francioli S, Hirschmann MT, Milz S, Valderrabano V, Heberer M, Martin I, Jakob M We present a novel method to support precise insertion of engineered osteochondral grafts by pulling from the bone layer, thereby minimizing iatrogenic damage associated with direct manipulation of the cartilage layer. Grafts were generated by culturing human expanded chondrocytes on Hyaff-11 meshes, sutured to Tutobone spongiosa cylinders. Through the bone layer, shaped to imitate the surface-contours of the talar dome, two sutures were applied: the first for anterograde implantation, to pull the graft into the defect, and the second for retrograde correction, in case of a too deep insertion. All grafts could be correctly positioned into osteochondral lesions created in cadaveric ankle joints with good fit to the surrounding cartilage. Implants withstood short-term dynamic stability tests applied to the ankle joint, without delamination or macroscopic damage. The developed technique, by allowing precise and stable positioning of osteochondral grafts without iatro! genic cartilage damage, is essential for the implantation of engineered tissues, where the cartilage layer is not fully mechanically developed, and could be considered also for conventional autologous osteochondral transplantation. PMID: 19305976 [PubMed - indexed for MEDLINE] | | | |
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