|  |  |  | | | | | TERMSC | | | | | | | | | | | | | | | | | | | The administration of BDNF and GDNF to the brain via PLGA microparticles patterned within a degradable PEG-based hydrogel: Protein distribution and the glial response. J Biomed Mater Res A. 2011 Jan 14; Authors: Lampe KJ, Kern DS, Mahoney MJ, Bjugstad KB Tailored delivery of neurotrophic factors (NFs) is a critical challenge that continues to inhibit strategies for guidance of axonal growth in vivo. Of particular importance is the ability to recreate innervation of distant brain regions by transplant tissue, for instance rebuilding the nigrostriatal track, one focus in Parkinson's disease research. Many strategies have utilized polymer drug delivery to target NF release in space and time, but combinatorial approaches are needed to deliver multiple NFs at relevant therapeutic times and locations without toxic side effects. Here we engineered a paradigm of PLGA microparticles entrapped within a degradable PEG-based hydrogel device to locally release two different types of NFs with two different release profiles. Hydrogel/microparticle devices were developed and analyzed for their ability to release GDNF in the caudal area of the brain, near the substantia nigra, or BDNF in the rostral area, near the striatum. The devices delivered their respective NFs in a region localized to within 100 μm of the bridge, but not exclusively to the targeted rostral or caudal ends. BDNF was slowly released over a 56-day period, whereas a bolus of GDNF was released around 28 days. The timed delivery of NFs from implanted devices significantly reduced the microglial response relative to sham surgeries. Given the coordinated drug delivery ability and reduced localized inflammatory response, this multifaceted PEG hydrogel/PLGA microparticle strategy may be a useful tool for further development in combining tissue engineering and drug delivery, and recreating the nigrostriatal track. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2011. PMID: 21240939 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Modelling the long QT syndrome with induced pluripotent stem cells. Nature. 2011 Jan 16; Authors: Itzhaki I, Maizels L, Huber I, Zwi-Dantsis L, Caspi O, Winterstern A, Feldman O, Gepstein A, Arbel G, Hammerman H, Boulos M, Gepstein L The ability to generate patient-specific human induced pluripotent stem cells (iPSCs) offers a new paradigm for modelling human disease and for individualizing drug testing. Congenital long QT syndrome (LQTS) is a familial arrhythmogenic syndrome characterized by abnormal ion channel function and sudden cardiac death. Here we report the development of a patient/disease-specific human iPSC line from a patient with type-2 LQTS (which is due to the A614V missense mutation in the KCNH2 gene). The generated iPSCs were coaxed to differentiate into the cardiac lineage. Detailed whole-cell patch-clamp and extracellular multielectrode recordings revealed significant prolongation of the action-potential duration in LQTS human iPSC-derived cardiomyocytes (the characteristic LQTS phenotype) when compared to healthy control cells. Voltage-clamp studies confirmed that this action-potential-duration prolongation stems from a significant reduction of the cardiac potassium current I(Kr). Importantly, LQTS-derived cells also showed marked arrhythmogenicity, characterized by early-after depolarizations and triggered arrhythmias. We then used the LQTS human iPSC-derived cardiac-tissue model to evaluate the potency of existing and novel pharmacological agents that may either aggravate (potassium-channel blockers) or ameliorate (calcium-channel blockers, K(ATP)-channel openers and late sodium-channel blockers) the disease phenotype. Our study illustrates the ability of human iPSC technology to model the abnormal functional phenotype of an inherited cardiac disorder and to identify potential new therapeutic agents. As such, it represents a promising paradigm to study disease mechanisms, optimize patient care (personalized medicine), and aid in the development of new therapies. PMID: 21240260 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Human Disc Nucleus Properties and Vertebral Endplate Permeability. Spine (Phila Pa 1976). 2011 Jan 13; Authors: Rodriguez AG, Slichter CK, Acosta FL, Rodriguez-Soto AE, Burghardt AJ, Majumdar S, Lotz JC Study Design: Experimental quantification of relationships between vertebral endplate morphology, permeability, disc cell density, glycosaminoglycan content and degeneration in samples harvested from human cadaveric spines.Objective: To test the hypothesis that variation in endplate permeability and porosity contribute to changes in intervertebral disc cell density and overall degeneration.Summary of Background Data: Cells within the intervertebral disc are dependent on diffusive exchange with capillaries in the adjacent vertebral bone. Previous findings suggest that blocked routes of transport negatively affect disc quality, yet there are no quantitative relationships between human vertebral endplate permeability, porosity, cell density and disc degeneration. Such relationships would be valuable for clarifying degeneration risk factors, and patient features that may impede efforts at disc tissue engineering.Methods: Fifty-one motion segments were harvested from 13 frozen cadaveric human lumbar spines (32 to 85 years) and classified for degeneration using the MRI-based Pfirrmann scale. A cylindrical core was harvested from the center of each motion segment that included vertebral bony and cartilage endplates along with adjacent nucleus tissue. The endplate mobility, a type of permeability, was measured directly using a custom-made permeameter before and after the cartilage endplate was removed. Cell density within the nucleus tissue was estimated using the picogreen method while the nuclear GAG content was quantified using the DMMB technique. Specimens were imaged at 8 μm resolution using microCT, bony porosity was calculated. Analysis of variance, linear regression, and multiple comparison tests were used to analyze the data.Results: Nucleus cell density increased as the disc height decreased (R = 0.13; p = 0.01) but was not related to subchondral bone porosity (p>0.5), total mobility (p>0.4) or age (p>0.2). When controlling for disc height however, a significant, negative effect of age on cell density was observed (p = 0.03). In addition to this, GAG content decreased with age non-linearly (R = 0.83, p<0.0001) and a cell function measurement, GAGs/cell decreased with degeneration (R = 0.24; p<0.0001). Total mobility (R = 0.14; p<0.01) and porosity (R = 0.1, p<0.01) had a positive correlation with age.Conclusion: Although cell density increased with degeneration, cell function indicated that GAGs/cell decreased. Since permeability and porosity increase with age and degeneration, this implies that cell dysfunction, rather than physical barriers to transport, accelerate disc disease. PMID: 21240044 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Expression of Transforming Growth Factor-β-Responsive Smads in Cranial Suture Development and Closure. J Craniofac Surg. 2011 Jan;22(1):324-8 Authors: Tholpady SS, Ogle RC The transforming growth factor-β (TGF-β) family of extracellular signaling molecules is heavily involved in developmental events, including patterning, formation, maintenance, and closure of the cranial suture. Several studies have demonstrated that TGF-βs are temporally and spatially localized to the suture and play a pivotal role in sutural state. These signals are translated into intracellular activity through a family of proteins known as smads. There are 8 known smads, with smads 1, 5, and 8 transducing BMP signals and smads 2 and 3 transducing TGF-β signals. Dimerization of any of these smads and smad 4 is necessary for phosphorylation and activation.Although many studies have delineated the presence of TGF-β during suture closure, no studies have determined smad activity. It was hypothesized that smad activity would change during sutural closure. Reverse transcription-polymerase chain reaction was used to determine whether TGF-β-responsive smads were present in the suture at which point they were immunohistochemically localized. A rat model was used in which the posterior intrafrontal suture fused during neonatal days 16 to 22. Time points before and after this event were analyzed for changes in smad expression and function.It was determined from these experiments that (1) the TGF-β-responsive smads 2, 3, and 4 are all present in the suture; (2) smads 2 and 4 are distributed in the region of the osteogenic front of the suture; and (3) smad 2/4 activity decreases in areas in which presumptive bone will form. These results add to the knowledge present about sutural development and may provide news targets to which therapeutics can be developed. PMID: 21239927 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Deformational plagiocephaly: a look into the future. J Craniofac Surg. 2011 Jan;22(1):3-5 Authors: Levi B, Wan DC, Longaker MT, Habal MB PMID: 21239916 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Stem cells as a resource for regenerative neurology. Pract Neurol. 2011 Feb;11(1):29-36 Authors: Connick P, Patani R, Chandran S Public and media interest in the potential applications of stem cells in regenerative neurology has led to growing hope and expectation. This interest is heightened by the current paucity of treatments available for neurodegenerative diseases and their generally poor prognosis. Patient discussions about stem cells are therefore a common occurrence in clinical practice, requiring neurologists to offer clear and accurate information. In the context of a complex and rapidly evolving field, this can be extremely challenging. Here we address issues around stem cell populations relevant to regenerative neurology, including the opportunities they offer for research and their potential application as direct therapies, concluding with a pragmatic assessment of the likely clinical benefits of stem cell research. PMID: 21239652 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | The development and translation of the tissue-engineered vascular graft. J Pediatr Surg. 2011 Jan;46(1):8-17 Authors: Breuer CK This lecture will define the classic tissue engineering paradigm, describe cell trafficking with regard to neotissue formation, and explain the role of the host in neotissue formation. PMID: 21238633 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Noggin and Wnt3a enable BMP4-dependent differentiation of telencephalic stem cells into GluR-agonist responsive neurons. Mol Cell Neurosci. 2011 Jan 13; Authors: Andersson T, Duckworth JK, Fritz N, Lewicka M, Södersten E, Uhlén P, Hermanson O Early telencephalic development is dependent on the spatially and temporally coordinated regulation by essential signaling factors. For example, members of the Bone Morphogenetic Protein (BMP) family, such as BMP4, are crucial for proper development of dorsal telencephalic structures. Stimulation of multipotent telencephalic neural stem cells (NSCs) with BMP4 induces differentiation primarily into astrocytic and mesenchymal cells. However, BMP4-mediated mesenchymal differentiation is inhibited at certain culture conditions of NSCs, corresponding to in vivo developmental contexts. These inhibitory mechanisms are not fully understood and the terminal fate of non-astrocytic BMP4 treated NSCs under these conditions is unclear. Here we show that secreted factors inhibited BMP4-mediated mesenchymal differentiation of telencephalic NSCs. BMP4 mediated a dramatic and direct up-regulation of endogenous noggin levels, that in turn exerted a concentration-dependent inhibition of BMP4-mediated mesenchymal differentiation of NSCs. Instead, BMP4 exposure of NSCs induced neuronal differentiation in mesenchyme-preventing conditions, whereas treatment with recombinant noggin alone did not. Wnt signaling is known to be essential for the development of neurons derived from the dorsal telencephalon, and co-stimulation of NSCs with BMP4+Wnt3a resulted in a synergistic effect yielding significantly increased number of mature neurons compared to stimulation with each factor alone. Thus whereas only a subset of BMP4-induced neurons derived from telencephalic NSCs, responded to glutamate receptor (GluR) agonists, over 80% of BMP4+Wnt3a-induced neurons responded appropriately to GluR-agonists. Our results increase the understanding of the role for BMP4 in differentiation of telencephalic multipotent progenitors, and reveal novel implications for noggin and Wnt3a in these events. PMID: 21238590 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Purified hematopoietic stem cell transplantation: the next generation of blood and immune replacement. Hematol Oncol Clin North Am. 2011 Feb;25(1):75-87 Authors: Czechowicz A, Weissman IL Replacement of disease-causing stem cells with healthy ones has been achieved clinically via hematopoietic cell transplantation (HCT) for the last 40 years, as a treatment modality for a variety of cancers and immunodeficiencies with moderate, but increasing, success. This procedure has traditionally included transplantation of mixed hematopoietic populations that include hematopoietic stem cells (HSC) and other cells, such as T cells. This article explores and delineates the potential expansion of this technique to treat a variety of inherited diseases of immune function, the current barriers in HCT and pure HSC transplantation, and the up-and-coming strategies to combat these obstacles. PMID: 21236391 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Antimicrobial tolerance and the significance of persister cells in recalcitrant chronic wound biofilms. Wound Repair Regen. 2011 Jan;19(1):1-9 Authors: Percival SL, Hill KE, Malic S, Thomas DW, Williams DW The application of antimicrobials in the management of wounds is a complex procedure requiring appropriate clinical decision making, judgment and a thorough understanding of antimicrobial therapies, together with their potential disadvantages. There is considerable direct and indirect evidence for the presence of bacterial biofilms in the chronic wound bed, and it has been demonstrated that bacteria within these biofilms may exhibit both specific and nonspecific antimicrobial tolerance. The antimicrobial tolerance of biofilms is a major concern in the treatment of both infected and nonhealing chronic wounds and an understanding of the mechanisms involved is of fundamental importance in managing wound infections and developing future wound management strategies. The aim of this review is therefore to provide an overview of our current understanding of the mechanisms by which bacteria in wound biofilms can resist conventional antibiotic and antibacterial therapies which is very important to wound healing. PMID: 21235682 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Human platelet lysate supports ex vivo expansion and enchances osteogenic differentiation of human bone marrow-derived mesenchymal stem cells. Cell Biol Int. 2011 Jan 14; Authors: Xia W, Li H, Wang Z, Xu R, Fu Y, Zhang X, Ye X, Huang Y, Xiang AP, Yu W Mesenchymal stem cells (MSCs) with their versatile growth and differentiation potential are ideal candidates for use in regenerative medicine and are currently making their way into clinical trials, which requires the development of xeno-free protocols for their culture. In this study, MSCs were cultured in 10% FCS or 7.5% human platelet lysate (HPL)-supplemented media. We found that both groups of MSCs showed a comparable morphology, phenotype and proliferation. The percentage of cells in the S and G2/M phases, however, was slightly up-regulated (p<0.01) in HPL group. HPL contains PDGF-AB and IGF-1. In addition, compared with FCS group, MSCs in HPL group showed an increase in osteogenic differentiation and a decrease in adipogenic differentiation. In conclusion, MSCs in HPL-supplemented media maintained similar growing potential and phenotype, while osteogenic potential was enhanced. HPL offers a promising alternative to FCS for MSC expansion for clinical application, especially in bone injury diseases. PMID: 21235529 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Mapping of the secretome of primary isolates of mammalian cells, stem cells and derived cell lines. Proteomics. 2010 Dec 15; Authors: Skalnikova H, Motlik J, Gadher SJ, Kovarova H Within a mammalian organism, the interaction among cells both at short and long distances is mediated by soluble factors released by cells into the extracellular environment. The secreted proteins may involve extracellular matrix proteins, proteinases, growth factors, protein hormones, immunoregulatory cytokines, chemokines or other bioactive molecules that have a direct impact on target cell phenotype. Stem cells of mesenchymal, adipose, neural and embryonic origin, fibroblast feeder cells as well as primary isolates of astrocytes, endothelial and muscle cells have recently become targets of intensive secretome profiling with the search for proteins regulating cell survival, proliferation, differentiation or inflammatory response. Recent advances and challenges of the stem cell and primary cell secretome analysis together with the most relevant results are discussed in this review. PMID: 21241017 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | | | | |  | |  | |  |
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