|  |  |  | | | | | TE-RegenMed-StemCell feed | | | | | | | | | | | | | | | | | | | Phenotypic characterizations and comparison of adult dental stem cells with adipose-derived stem cells. Int J Prev Med. 2010;1(3):164-71 Authors: Alipour R, Sadeghi F, Hashemi-Beni B, Zarkesh-Esfahani SH, Heydari F, Mousavi SB, Adib M, Narimani M, Esmaeili N Mesenchymal stem cells or "multipotent stromal cells" are heterogeneous cell population with self-renewal and multilinage differentiation. The aim of this study was to examine and compare the expression of important stem cell surface markers on two populations of mesenchymal stem cells, one derived from human exfoliated deciduous teeth and the other derived from human adipose tissue. These new stem cells will offer a promising avenue for prevention and reversal of many human diseases such as type 1 diabetes and prevention of liver fibrotic process. PMID: 21566786 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Epicardial adipose stem cell sheets results in greater post-infarction survival than intramyocardial injections. Cardiovasc Res. 2011 May 12; Authors: Hamdi H, Planat-Benard V, Bel A, Puymirat E, Geha R, Pidial L, Nematalla H, Bellamy V, Bouaziz P, Peyrard S, Casteilla L, Bruneval P, Hagège AA, Agbulut O, Menasché P AIMS: Intramyocardial injections of cells can damage tissue and enhance dissociation-induced cell death. We assessed whether epicardial delivery of cell sheets could overcome these issues in a rat model of chronic myocardial infarction. METHODS AND RESULTS: Eighty-two rats that had undergone coronary ligation and simultaneous harvest of fat tissue to yield the adipose-derived stromal cell (ADSC) fraction were randomized 1 month after infarction to receive injections of either control medium (n= 24) or 10 × 10(6) autologous ADSC (n= 37) or the epicardial deposit, onto the infarcted area, of a trilayered ADSC sheet (10 × 10(6), n= 21) prepared by culturing cells on temperature-sensitive dishes. Some treated rats received green fluorescent protein labelled ADSC. Survival, function, and cell engraftment were blindly assessed after 2 months. Prior to implantation, cell sheets and suspended cells were assessed for the expression of extracellular matrix constituents and molecules involved in angiogenesis and cardiac remodelling. The survival rate of rats receiving the cell sheets was significantly higher than after cell injections (73 vs. 41%, P = 0.01). This correlated with the absence of left ventricular (LV) remodelling in the cell sheet group, as end-diastolic volume only increased by 2.8% compared with baseline [95% confidence interval (CI): -18.7%; +30.0%, P = 0.81] vs. increases of 25.9% (-0.4%; +59.2%, P = 0.05) and 51.2% (+18.6%; +92.8, P = 0.001) in the cell and medium injection groups, respectively. Sheets also resulted in a greater cell engraftment possibly related to the greater expression of extracellular matrix constituents. CONCLUSION: The better preservation of LV geometry afforded by ADSC sheets is associated with increased survival and engraftment, which supports the concept of an epicardial delivery of cell-seeded biomaterials. PMID: 21565832 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Improving the efficacy of type 1 diabetes therapy by transplantation of immunoisolated insulin-producing cells. Hum Cell. 2011 May 13; Authors: Ngoc PK, Phuc PV, Nhung TH, Thuy DT, Nguyet NT Type 1 diabetes occurs when pancreatic islet β-cells are damaged and are thus unable to secrete insulin. Pancreas- or islet-grafting therapy offers highly efficient treatment but is limited by inadequate donor islets or pancreases for transplantation. Stem-cell therapy holds tremendous potential and promises to enhance treatment efficiency by overcoming the limitations of traditional therapies. In this study, we evaluated the efficiency of preclinical diabetic treatment. Diabetes was induced in mice by injections of streptozotocin. Mesenchymal stem cells (MSCs) were derived from mouse bone marrow or human umbilical cord blood and subsequently differentiated into insulin-producing cells. These insulin-producing cells were encapsulated in an alginate membrane to form capsules. Finally, these capsules were grafted into diabetic mice by intraperitoneal injection. Treatment efficiency was evaluated by monitoring body weight and blood glucose levels. Immune reactions after transplantation were monitored by counting total white blood cells. Allografting or xenografting of encapsulated insulin-producing cells (IPCs) reduced blood glucose levels and increased body weight following transplantation. Encapsulation with alginate conferred immune isolation and prevented graft rejection. These results provide further evidence supporting the use of allogeneic or xenogeneic MSCs obtained from bone marrow or umbilical cord blood for treating type 1 diabetes. PMID: 21567289 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Recruitment of Stem Cells Into the Injured Retina After Laser Injury. Stem Cells Dev. 2011 May 11; Authors: Singh T, Prabhakar S, Gupta A, Anand A Retinal degeneration is a devastating complication of diabetes and other disorders. Stem cell therapy for retinal regeneration has shown encouraging results but functional regeneration has not yet been achieved. Our study was undertaken to evaluate the localization of stem cells delivered to the retina by intravenous vs intravitreal infusion since stem cell localization is a key factor in ultimate in vivo function. We used lineage negative bone marrow derived stem cells in a model wherein retina of mice was induced by precise and reproducible laser injury. Lin-ve BMCs were labeled with a tracking dye and their homing capacity was analyzed at time points after infusion. We found that Lin-ve BMCs get incorporated into laser injured retina when transplanted through either the intravitreal or intravenous route. The intravenous route resulted in optimal localization of donor cells at the site of injury. These cells incorporated into injured retina in a dose dependent manner. The data presented in this study reflects the importance of dose and route for stem cell-based treatment designed to result in retinal regeneration. PMID: 21561324 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | [Cardiac stem cell therapy for the treatment of chronic stable angina refractory to conventional therapy. State of the art and current clinical experience of the San Raffaele Hospital of Milan, Italy]. G Ital Cardiol (Rome). 2011 Mar;12(3):198-211 Authors: Godino C, Briguori C, Airoldi F, Toia P, Saolini M, Ferrari A, Cera M, Fragasso G, Imros MA, Salomoni M, Todeschini P, Gajate AM, Gianolli L, Oppizzi M, Capogrossi MC, Condorelli G, Colombo A Cardiac stem cell therapy is a field of scientific research with the goal to translate into clinical benefit the initial findings obtained in basic research laboratories. We have moved into clinical trials in different disease categories: acute myocardial infarction, chronic stable angina refractory to conventional therapy and heart failure. So far we have faced with contradictory results. Some previous studies suggested that bone marrow cell injection may improve myocardial perfusion and left ventricular function in patients with chronic myocardial ischemia. PMID: 21560476 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Hypoxic Preconditioning Enhances Bone Marrow Mesenchymal Stem Cell Migration via Kv2.1 Channel and FAK Activation. Am J Physiol Cell Physiol. 2011 May 11; Authors: Hu X, Wei L, Taylor TM, Wei J, Zhou X, Wang JA, Yu SP Transplantation using stem cells including bone marrow mesenchymal stem cells (BMSCs) is emerging as a potential regenerative therapy after ischemic attacks in the heart and brain. The migration capability of transplanted cells is a critical cellular function for tissue repair. Based on our recent observations that hypoxic preconditioning (HP) has multiple benefits in improving stem cell therapy and that the potassium Kv2.1 channel acts as a promoter for focal adhesion kinase (FAK) activation and cell motility, the present investigation tested the hypothesis that HP treatment can increase BMSC migration via the mechanism of increased Kv2.1 expression and FAK activities. BMSCs derived from green fluorescent protein (GFP)-transgenic mice were treated under either normoxic (N-BMSC) or hypoxic (0.5% O(2)) (HP-BMSC) conditions for 24 hrs. Western blotting showed HP selectively upregulated Kv2.1 expression while leaving other K(+) channels, such as Kv1.5 and Kv1.4, unaffected. Compared to normoxic controls, significantly larger outward delayed rectifier K(+) currents were recorded in HP-BMSCs. HP enhanced BMSC migration/homing activities in vitro and after intravenous transplantation into rats subjected to permanent myocardial infarction (MI). The HP-promoted BMSC migration was inhibited by either blocking K(+) channels or knocking down Kv2.1. Supporting a relationship among HP, Kv2.1 and FAK activation, HP increased phosphorylation of FAK(397) and FAK(576)/(577) and this effect was antagonized by blocking K(+) channels. These findings provide novel evidence that hypoxic preconditioning enhances the ability of BMSCs to migrate and homing to the injured region; this effect is mediated through a regulatory role of Kv2.1 on FAK phosphorylation/activation. PMID: 21562308 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Stem cells in regenerative medicine: introduction. Br Med Bull. 2011 May 11; Authors: Ilic D, Polak JM Background Considerable amount of information about the potential of stem cell therapy in regenerative medicine is available today. Scientific meetings and publications in specialized journals enable experts in stem cell science and regenerative medicine to follow worldwide cutting-edge research. However, controversial information plaguing the media and the Internet lead patients to believe that stem cells are the long-awaited panacea even though there are little or no stringent factual data available yet. Sources of data PubMed database systematically searched in the period 4-6 January 2011. Areas of agreement Stem cell-based therapy is a future of regenerative medicine. Areas of controversy Based on unsubstantial claims fueled by media, patients are frequently seeking advice about the risks and prospects of specific therapeutic regimes from their physicians. Reports in specialized journals written in a scientific vocabulary are difficult to evaluate for many primary-care physicians. Hence, physicians are reluctant to provide advice or endorse treatment options for cell-based therapies. Areas timely for further development We wish to fill the gap and offer physicians suitable guidance. By giving a comprehensive overview of different types of stem cells and their potential in a simple language, here we are introducing a series of articles written by world-renowned experts on regenerative medicine about the current status and prospects of the field from the point of view of the standard level of patient safety and efficacy for the healthcare industry. PMID: 21565803 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Study of Pluripotency Markers in Zebrafish Embryos and Transient Embryonic Stem Cell Cultures. Zebrafish. 2011 May 12; Authors: Robles V, Martí M, Belmonte JC Abstract Targeted genomic manipulation using embryonic stem (ES) cells has not yet been achieved in zebrafish, although methods for zebrafish ES cell culture has been described in literature. The knowledge of pluripotency markers in this species is almost nonexistent and this is a very limiting factor in the definition of the ideal culture conditions for ES cells. Here, we studied the expression of several genes associated with pluripotency in zebrafish embryonic cells versus differentiated cells and the expression of some of these genes is recorded throughout embryonic development. Some of the commonly accepted pluripotency markers are also tested in embryonic cells, transient embryonic cell cultures, and differentiated cells. Our results support the hypothesis that stage-specific embryonic antigen 1 (SSEA1) is a marker that precedes the expression of pluripotency genes in a zebrafish embryonic cell colony, in the same way that SOX2 precedes nestin expression in those colonies that have already started differentiation toward neurons. We consider this study a step forward in the knowledge of zebrafish pluripotency markers and, therefore, an important tool for the monitoring of zebrafish embryonic cell cultures. PMID: 21563922 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Methodological Development of a Clonogenic Assay to Determine Endothelial Progenitor Cell Potential. Circ Res. 2011 May 12; Authors: Masuda H, Alev C, Akimaru H, Ito R, Shizuno T, Kobori M, Horii M, Ishihara T, Isobe K, Isozaki M, Itoh J, Itoh Y, Okada Y, McIntyre BA, Kato S, Asahara T The precise and conceptual insight of circulating endothelial progenitor cell (EPC) kinetics is hampered by the absence of an assay system capable of evaluating the EPC differentiation cascade. An assay system for EPC colony formation was developed to delineate circulating EPC differentiation. EPC colony-forming assay using semisolid medium and single or bulk CD133(+) cells from umbilical cord blood exhibited the formation of two types of attaching cell colonies made of small or large cells featuring endothelial lineage potential and properties, termed small EPC colony-forming units and large EPC colony-forming units, respectively. In vitro and in vivo assays of each EPC colony-forming unit cell revealed a differentiation hierarchy from small EPC to large EPC colonies, indicating a primitive EPC stage with highly proliferative activity and a definitive EPC stage with vasculogenic properties, respectively. Experimental comparison with a conventional EPC culture assay system disclosed EPC colony-forming unit cells differentiate into noncolony-forming early EPC. The fate analysis of single CD133(+) cells into the endothelial and hematopoietic lineage was achieved by combining this assay system with a hematopoietic progenitor assay and demonstrated the development of colony-forming EPC and hematopoietic progenitor cells from a single hematopoietic stem cell. EPC colony-forming assay permits the determination of circulating EPC kinetics from single or bulk cells, based on the evaluation of hierarchical EPC colony formation. This assay further enables a proper exploration of possible links between the origin of EPC and hematopoietic stem cells, representing a novel and powerful tool to investigate the molecular signaling pathways involved in EPC biology. PMID: 21566217 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Pharmacological Response of Human Cardiomyocytes Derived from Viral-Free Induced Pluripotent Stem Cells. Cardiovasc Res. 2011 May 12; Authors: Mehta A, Chung YY, Ng A, Iskandar F, Atan S, Heming W, Dusting G, Sun W, Wong P, Shim W Aim Generation of human induced pluripotent stem cell (hiPSC) lines by reprogramming of fibroblast cells with viral-free methods offers unique opportunities for translational cardiovascular medicine. The aim of the study was to reprogram fibroblast cells to hiPSCs, study cardiomyogenic property and ion channel characteristics of the viral-free hiPSC-derived cardiomyocytes. Methods and Results hiPSCs generated by episomal based vectors generated teratomas in SCID mice, readily formed embryoid bodies and differentiated into cardiomyocytes with comparable efficiency to human embryonic stem cells. Temporal gene expression of these hiPSCs indicated that differentiation of cardiomyocytes was initiated by increasing expression of cardio/mesodermal markers, followed by cardiac-specific transcription factors, structural and ion channel genes. Furthermore, the cardiomyocytes showed characteristic cross-striations of sarcomeric proteins, expressed calcium handling and ion channel proteins, confirming their cardiac ontogeny. Microelectrode array recordings established the electrotonic development of a functional syncytium that responded predictably to pharmacologically active drugs. The cardiomyocytes showed chronotropic dose-response (0.1-10µM) to isoproterenol and Bay K8644. Furthermore, carbamycholine (5µM) suppressed the response to isoproterenol while verapamil (2.5µM) blocked Bay K8644 induced inotropic activity. Moreover, verapamil (1µM) reduced corrected field potential duration (cFPD) by 45% while tetrodotoxin (10µM) shortened minimal field potential (FP(min)) by 40% while E-4031 (50nM) prolonged field repolarization. Conclusions Viral-free hiPSCs efficiently differentiate into cardiomyocytes with cardiac-specific molecular, structural, and functional properties that recapitulate developmental ontogeny of cardiogenesis. These results, coupled with the potential to generate patient-specific hiPSC lines hold great promise for the development of in vitro platform for drug pharmacogenomics; disease modelling and regenerative medicine. PMID: 21565833 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Recruitment of Progenitor Cells by an ECM Cryptic Peptide in a Mouse Model of Digit Amputation. Tissue Eng Part A. 2011 May 12; Authors: Agrawal V, Tottey S, Johnson SA, Fruend JM, Siu BF, Badylak SF Biologic scaffolds composed of extracellular matrix (ECM) have been used successfully in preclinical models and humans for constructive remodeling of functional, site-appropriate tissue following injury. The mechanisms underlying ECM mediated constructive remodeling are not completely understood, but scaffold degradation and site directed recruitment of both differentiated and progenitor cells are thought to play critical roles. Previous studies have shown that degradation products of ECM scaffolds can recruit a population of progenitor cells both in vitro and in vivo. The present study identified a single cryptic peptide derived from the α subunit of the collagen III molecule that is chemotactic for a well characterized perivascular stem cell in vitro and causes the site directed accumulation of progenitor cells in vivo. The oligopeptide was additionally chemotactic for human cortical neural stem cells, rat adipocyte stem cells, C2C12 myoblast cells, and rat Schwann cells in vitro. In an adult murine model of digit amputation, treatment with this peptide following mid-second phalanx amputation resulted in a greater number of Sox2+ and Sca1+,Lin- cells at the site of injury compared to controls. Since progenitor cell activation and recruitment are key prerequisites for epimorphic regeneration in adult mammalian tissues, endogenous site directed recruitment of such cells has the potential to alter the default wound healing response from scar tissue towards regeneration. PMID: 21563860 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Methylation of RAR-β2, RASSF1A, and CDKN2A Genes Induced by Nickel Subsulfide and Nickel-carcinogenesis in Rats. Biomed Environ Sci. 2011 Apr;24(2):163-71 Authors: Zhang J, Zhang J, Li M, Wu Y, Fan Y, Zhou Y, Tan L, Shao Z, Shi H To investigate the expression variation of RAR-β2, RASSF1A, and CDKN2A gene in the process of nickel-induced carcinogenesis. PMID: 21565688 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Cryopreservation of Human Stem Cells for Clinical Application: A Review. Transfus Med Hemother. 2011;38(2):107-123 Authors: Hunt CJ SUMMARY: Stem cells have been used in a clinical setting for many years. Haematopoietic stem cells have been used for the treatment of both haematological and non-haematological disease; while more recently mesenchymal stem cells derived from bone marrow have been the subject of both laboratory and early clinical studies. Whilst these cells show both multipotency and expansion potential, they nonetheless do not form stable cell lines in culture which is likely to limit the breadth of their application in the field of regenerative medicine. Human embryonic stem cells are pluripotent cells, capable of forming stable cell lines which retain the capacity to differentiate into cells from all three germ layers. This makes them of special significance in both regenerative medicine and toxicology. Induced pluripotent stem (iPS) cells may also provide a similar breadth of utility without some of the confounding ethical issues surrounding embryonic stem cells. An essential pre-requisite to the commercial and clinical application of stem cells are suitable cryopreservation protocols for long-term storage. Whilst effective methods for cryopreservation and storage have been developed for haematopoietic and mesenchymal stem cells, embryonic cells and iPS cells have proved more refractory. This paper reviews the current state of cryopreservation as it pertains to stem cells and in particular the embryonic and iPS cell. PMID: 21566712 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Osteogenic differentiation is synergistically influenced by osteoinductive treatment and direct cell-cell contact between murine osteoblasts and mesenchymal stem cells. Int Orthop. 2011 May 13; Authors: Tsai MT, Lin DJ, Huang S, Lin HT, Chang WH PURPOSE: The present study was designed to address whether osteoblasts play a synergistic role in promoting mesenchymal stem cell (MSC) osteogenesis in a direct cell-cell contact co-culture model. METHODS: Murine C3H10T1/2 and MC3T3-E1 cell lines were mixed and plated onto 12-well culture plates and co-cultured at various ratios of initial cell densities. To compare the possible improvement on osteogenic differentiation, co-culture cells were served with or without osteogenic supplements in culture medium. RESULTS: Weak osteogenesis was induced in MSCs co-cultured in an untreated medium with different ratios of osteoblasts. An osteoblast-dependent increase in osteogenic gene expression of Runx2, type I collagen, and osteocalcin was observed over time. Moreover, both alkaline phosphatase (ALP) activity and calcium deposition were distinctly enhanced at levels that were proportional to the quantity of osteoblasts in the culture. The increases in mRNA expression and ALP activity were greater in co-cultures treated with osteogenic supplements than in untreated cultures. However, the production of ALP activity followed by a distinct matrix mineralization was lower in osteogenic-treated cultures containing greater numbers of osteoblasts. This suggests that a higher density of osteoblasts may lead to weak osteogenesis of MSCs by direct cell-cell contact co-culture in an untreated environment. Furthermore, additional osteogenic supplements may act synergistically with osteoblasts to accelerate matrix mineralization by reducing the process of osteogenic differentiation in osteogenic treated co-cultures. CONCLUSIONS: The present work may improve the understanding of MSC osteogenesis and may provide benefits for regenerative medicine. PMID: 21567150 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Stem cells in regenerative medicine: introduction. Br Med Bull. 2011 May 11; Authors: Ilic D, Polak JM Background Considerable amount of information about the potential of stem cell therapy in regenerative medicine is available today. Scientific meetings and publications in specialized journals enable experts in stem cell science and regenerative medicine to follow worldwide cutting-edge research. However, controversial information plaguing the media and the Internet lead patients to believe that stem cells are the long-awaited panacea even though there are little or no stringent factual data available yet. Sources of data PubMed database systematically searched in the period 4-6 January 2011. Areas of agreement Stem cell-based therapy is a future of regenerative medicine. Areas of controversy Based on unsubstantial claims fueled by media, patients are frequently seeking advice about the risks and prospects of specific therapeutic regimes from their physicians. Reports in specialized journals written in a scientific vocabulary are difficult to evaluate for many primary-care physicians. Hence, physicians are reluctant to provide advice or endorse treatment options for cell-based therapies. Areas timely for further development We wish to fill the gap and offer physicians suitable guidance. By giving a comprehensive overview of different types of stem cells and their potential in a simple language, here we are introducing a series of articles written by world-renowned experts on regenerative medicine about the current status and prospects of the field from the point of view of the standard level of patient safety and efficacy for the healthcare industry. PMID: 21565803 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Tailoring nanocarriers for intracellular protein delivery. Chem Soc Rev. 2011 May 12; Authors: Gu Z, Biswas A, Zhao M, Tang Y Proteins play a crucial role in life, taking part in all vital processes in the body. In the past decade, there was increasing interest in delivering active forms of proteins to specific cells and organs. Intracellular protein delivery holds enormous promise for biological and medical applications, including cancer therapy, vaccination, regenerative medicine, treatment for loss-of-function genetic diseases and imaging. This tutorial review surveys recent developments in intracellular protein delivery using various nanocarriers. Methods such as lipid-mediated colloidal systems, polymeric nanocarriers, inorganic systems and protein-mediated carriers are reviewed. Advantages and limitations of current strategies, as well as future opportunities and challenges are also discussed. PMID: 21566806 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Assessment of the biocompatibility of two novel, bionanocomposite scaffolds in a rodent model. J Biomed Mater Res B Appl Biomater. 2011 Feb;96(2):351-9 Authors: Deeken CR, Esebua M, Bachman SL, Ramshaw BJ, Grant SA Two novel, bionanocomposite scaffolds were evaluated in a rodent model over the course of three months to determine whether these scaffolds possessed adequate biocompatibility characteristics to warrant further evaluation as possible tissue reconstruction scaffolds. These bionanocomposite scaffolds were comprised of amine-functionalized gold nanoparticles (AuNP) or silicon carbide nanowires (SiCNW) crosslinked to an acellular porcine diaphragm tendon. It was hypothesized that the addition of nanomaterials to the porcine tendon would also improve its biocompatibility by imparting a nanostructured surface. As early as seven days after implantation, both types of bionanocomposite scaffolds displayed evidence of granulation tissue and the beginning of scaffold remodeling with new collagen deposited by the host, and by ninety-seven days the bionanocomposite scaffolds were completely remodeled with no evidence of any adverse host tissue reaction or scar tissue formation. The AuNP bionanocomposite scaffolds exhibited accelerated scaffold remodeling compared to the SiCNW scaffolds. PMID: 21210516 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Stromal cell-derived factor-1 and monocyte chemotactic protein-3 improve recruitment of osteogenic cells into sites of musculoskeletal repair. J Orthop Res. 2011 Jul;29(7):1064-9 Authors: Shinohara K, Greenfield S, Pan H, Vasanji A, Kumagai K, Midura RJ, Kiedrowski M, Penn MS, Muschler GF Homing of osteogenic cells through the systemic circulation represents an alternative to traditional orthopedic tissue engineering approaches that focus on local cell populations. We hypothesize that expression of the chemokine, stromal cell-derived factor-1 (SDF-1) or monocyte chemotactic protein-3 (MCP-3) may enhance homing of osteogenic cells into sites of fracture repair, as both have demonstrated promise in recruitment of marrow stromal cells (MSCs). This hypothesis was tested by transplantation of culture expanded MSCs expressing these factors adjacent to a fracture site on a collagen scaffold. One green fluorescent protein positive (GFP(+) ) and one wild-type mouse were surgically conjoined as parabiots at 7-8 weeks of age. Fibular osteotomy was performed 4 weeks after parabiosis on the hind limb of the wild-type mouse. Mice were randomly allocated to receive one of the following five treatments: control (no scaffold), empty scaffold (no cells), or scaffold containing MSCs, scaffold containing MSCs expressing SDF-1, or scaffold containing MSCs expressing MCP-3. Fracture callus was harvested 2 weeks after injury, and analyzed with confocal microscopy and cell-counting software. When compared to fracture callus treated with nontransfected MSCs, the fracture callus of mice treated with both SDF-1 and MCP-3 secreting MSCs demonstrated a significant increase in the number of both GFP(+) cells (p = 0.0003, p = 0.02) and GFP(+) /AP(+) cells (p = 0.0005, p = 0.01). These data suggest that homing of osteogenic cells from systemic circulation participate in fracture repair and that homing pathways might be modulated to enhance the contribution of circulating progenitors at the site of skeletal injury. © 2011 Orthopaedic Research Society Published by Wiley Periodicals, Inc. J Orthop Res 29: 1064-1069, 2011. PMID: 21567452 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Electrospun poly (ɛ-caprolactone)/silk fibroin core-sheath nanofibers and their potential applications in tissue engineering and drug release. Int J Biol Macromol. 2011 May 5; Authors: Li L, Li H, Qian Y, Li X, Singh GK, Zhong L, Liu W, Lv Y, Cai K, Yang L One of the key tenets of tissue engineering is to develop scaffold materials with favorable biodegradability, surface properties, outstanding mechanical strength and controlled drug release property. In this study, we generated core-sheath nanofibers composed of poly (ɛ-caprolactone) (PCL) and silk fibroin (SF) blends via emulsion electrospinning. Nanofibrous scaffolds were characterized by combined techniques of scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), differential scanning calorimetry (DSC), contact angle and tensile measurements. An in vitro FITC release study was conducted to evaluate sustained release potential of the core-sheath structured nanofibers. We found that the conformation of SF contained in PCL/SF composite nanofibers was transformed from random coil to β-sheet when treated with methanol, leading to improved crystallinity and tensile strength of nanofibrous scaffolds. The hydrophobicity and diameter of nanofibers decreased when we increased the content of SF in PCL/SF composite nanofibers. Furthermore, we evaluated the potential of fabricated PCL/SF composite nanofibers as scaffold in vitro. The results confirmed that fabricated PCL/SF scaffolds improved cell attachment and proliferation. Our results demonstrated the feasibility to generate core-sheath nanofibers composed of PCL and SF using a single-nozzle technique. The produced nanofibrous scaffolds with sustained drug release have potential application in tissue engineering. PMID: 21565216 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Ring-Opening Metathesis Polymerization-Based Synthesis of CaCO(3) Nanoparticle-Reinforced Polymeric Monoliths for Tissue Engineering. Macromol Rapid Commun. 2010 Sep 1;31(17):1540-5 Authors: Weichelt F, Frerich B, Lenz S, Tiede S, Buchmeiser MR Porous monolithic materials have been prepared via ring-opening metathesis polymerization from norborn-2-ene and a 7-oxanorborn-2-ene-based cross-linker in the presence of porogenic solvents (i.e., 2-propanol and toluene) and norborn-2-enephosphonate surface-modified CaCO(3) nanoparticles, using the 3(rd) -generation Grubbs-initiator RuCl(2) (Py)(2) (IMesH(2) )(CHPh). The experimental setup and the conditions chosen allowed for the manufacturing of polymeric monoliths characterized by a homogeneous distribution of the inorganic nanoparticles throughout the polymeric monolith. Depending on the nanoparticle content, the macropore diameters could be varied in the 30-120 µm regime. Noteworthy, the addition of nanoparticles did not affect the phase separation-triggered formation of the monolithic matrix nor the meso- and microporosity as evidenced by N(2) -adsorption experiments. PMID: 21567564 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | MRI and histologic analysis of collagen type II sponge on repairing the cartilage defects of rabbit knee joints. J Biomed Mater Res B Appl Biomater. 2011 Feb;96(2):267-75 Authors: Chen H, Yang X, Liao Y, Zeng X, Liang P, Kang N, Tan J, Liang Z There are limited treatment options for cartilage defects in clinical practice because of the lack of suitable biomaterials. Here, we evaluated the effects of collagen type II sponge on the articular cartilage repairing process using a cartilage injury of a rabbit knee joint model. We showed that the home-made collagen type II sponges appeared to have a suitable pore size of 93.26 ± 38.4 μm for chondrocyte growth. MRI with H&E staining results demonstrated that the effusion absorption in the collagen type II sponge treated group was quicker than that of the control group. Moreover, sporadic cartilage signals first appeared at 6 weeks in the collagen type II sponge treated group. Safranin O staining and immunohistochemical analysis confirmed that the newly formed cartilage expresses glycosaminoglycan and type II collagen matrix. Using Sirius red polarized light staining, we showed that the newly formed cartilage-like areas from the collagen type II treated group are significantly greater than those of the control group. Taken together, our data demonstrated that the home-made collagen type II sponge is able to promote cartilage repair in the cartilage injury of a rabbit knee joint model. PMID: 21210506 [PubMed - indexed for MEDLINE] | | | | | | | | | |  | |  | |  |
No comments:
Post a Comment