http://hdl.handle.net/10379/5440 2017-10-29T22:43:38Z http://hdl.handle.net/10379/6430 Fibrin as a scaffold for delivery of GDNF overexpressing stem cells to the adult rat brain Moloney, Teresa C.; Kulkarni, Mangesh; Ní Fhlathartaigh1, Mary; Abhay, Pandit; Dowd, Eilís Treatment of neurodegenerative disease is entering a new era where direct intracerebral delivery of therapeutic factors aims to restore normality to dysfunctional circuits. Cell-based therapeutic approaches, where virally manipulated mesenchymal stem cells (MSCs) overexpressing glial cell line derived neurotrophic factor (GDNF) are utilized as vehicles to deliver neurotrophic support to the Parkinsonian brain, have shown promising preclinical results at preserving dopaminergic neuron integrity. However, poor cell survival following transplantation will hinder clinical progression. One approach to improve MSCs survival following transplantation is to couple the cell engraftment procedure with a scaffold thereby providing a physical substrate upon which to eventually complex pro-survival factors. Evaluation of commercially available, clinically accepted materials with an established safety profile will expedite clinical translation. Therefore, this study sought to determine if a clinically used fibrin scaffold can be utilized as an adjunct to intracerebral cell transplantation without evoking an adverse host or stem cell response. Sixteen male Sprague−Dawley rats received bilateral intrastriatal transplants of 30 000 GDNF-transduced MSCs delivered in either control transplantation medium or a fibrin scaffold. Rats were sacrificed 1, 4, 7, and 14 days post-transplantation. Brains were analyzed to determine in situ polymerization and biodegradability of the fibrin scaffold, GDNF release from transplanted GDNF-MSCs, survival of the GDNFMSC graft and the host s immune response to the transplant. This study found that fibrin scaffold was adaptable to intracerebral delivery with successful polymerization of the fibrin scaffold in situ. Inclusion of the fibrin scaffold was not detrimental to cell survival nor did it impede neurotrophin release from entrapped cells. Importantly, the inclusion of the fibrin scaffold was associated with a reduced host astroglial and microglial response compared to cells alone indicative of a favorable biocompatibility profile. Overall, fibrin represents an adaptable scaffold for inclusion in a minimally invasive cell-based therapeutic approach for neurodegenerative diseases. 2017-04-05T00:00:00Z http://hdl.handle.net/10379/5625 An injectable elastin-based gene delivery platform for dose-dependent modulation of angiogenesis and inflammation for critical limb ischemia Dash, Biraja C.; Thomas, Dilip; Monaghan, Michael; Carroll, Oliver; Chen, Xizhe; Woodhouse, Kimberly; O'Brien, Timothy; Pandit, Abhay Critical limb ischemia is a major clinical problem. Despite rigorous treatment regimes, there has been only modest success in reducing the rate of amputations in affected patients. Reduced level of blood flow and enhanced inflammation are the two major pathophysiological changes that occur in the ischemic tissue. The objective of this study was to develop a controlled dual gene delivery system capable of delivering therapeutic plasmid eNOS and IL-10 in a temporal manner. In order to deliver multiple therapeutic genes, an elastin-like polypeptide (ELP) based injectable system was designed. The injectable system was comprised of hollow spheres and an in situ-forming gel scaffold of elastin-like polypeptide capable of carrying gene complexes, with an extended manner release profile. In addition, the ELP based injectable system was used to deliver human eNOS and IL-10 therapeutic genes in vivo. A subcutaneous dose response study showed enhanced blood vessel density in the treatment groups of eNOS (20 rig) and IL-10 (10 mu g)/eNOS (20 mu g) and reduced inflammation with IL-10 (10 mu g) alone. Next, we carried out a hind-limb ischemia model comparing the efficacy of the following interventions; Saline; IL-10, eNOS and IL-10/eNOS. The selected dose of eNOS, exhibited enhanced angiogenesis. IL-10 treatment groups showed reduction in the level of inflammatory cells. Furthermore, we demonstrated that eNOS up-regulated major proangiogenic growth factors such as vascular endothelial growth factors, platelet derived growth factor B, and fibroblast growth factor 1, which may explain the mechanism of this approach. These factors help in formation of a stable vascular network. Thus, ELF injectable system mediating non-viral delivery of human IL10-eNOS is a promising therapy towards treating limb ischemia. (C) 2015 Elsevier Ltd. All rights reserved. 2015-10-01T00:00:00Z http://hdl.handle.net/10379/5624 Hyaluronic acid based hydrogels attenuate inflammatory receptors and neurotrophins in interleukin-1 beta induced inflammation model of nucleus pulposus cells Isa, Isma Liza Mohd; Srivastava, Akshay; Tiernan, David; Owens, Peter; Rooney, Peadar; Dockery, Peter; Pandit, Abhay Inflammation plays an important role in symptomatic intervertebral disc degeneration and is associated with the production of neurotrophins in sensitizing innervation into the disc. The use of high molecular weight (HMw) hyaluronic acid (HA) hydrogels offers a potential therapeutic biomaterial for nucleus pulposus (NP) regeneration as it exerts an anti-inflammatory effect and provides a microenvironment that is more suitable for NP. Therefore, it was hypothesized that cross-linked HMw HA hydrogels modulate the inflammatory receptor of IL-1R1, MyD88 and neurotrophin expression of nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF) in an in vitro inflammation model of NP. HA cross-linking was optimized using various concentrations of 4-arm PEG-amine by determination of free carboxyl groups of HA and unreacted free amine groups of PEG-amine. The optimally cross-linked HA hydrogels were characterized for hydrolytic stability, enzymatic degradation and cytotoxicity on NP cells. The therapeutic effect of HA hydrogels was further investigated in IL-1 beta induced inflammation on NP cell cultures and the mechanism of HA by examining the expression of cell surface receptor of CD44. Hydrogel was optimally cross-linked at 75 mM PEG, stable in phosphate buffered saline, and showed greater than 40% resistance to enzymatic degradation. No cytotoxic effect of NP cells was observed in the presence of hydrogels for 1, 3, and 7 days. IL-1R1 and MyD88 were significantly suppressed. Additionally, NGF and BDNF mRNA were down-regulated after treatment with cross-linked HA hydrogel. Possible protective mechanism of HA is shown by high expression of CD44 receptor of NP cells after HA treatment in which suggest the binding of HA to CD44 receptor and prevent NP cells from further undergoing inflammation. These results indicate that optimally stabilized cross-linked HMw HA hydrogel has a therapeutic effect in response to inflammation-associated pain and becomes an ideal matrices hydrogel for NP regeneration. 2015-04-14T00:00:00Z http://hdl.handle.net/10379/5510 Synthesis of polymer-silica hybrid microparticles with defined geometry using surface initiated atom transfer radical polymerization del Monte, F.; Lang, Y.; Finn, David P.; Pandit, Abhay; Wang, Wenxin Nanostructured polymer/silica hybrid materials have gained attention as they combine the advantageous properties of organic and inorganic materials in one entity. Herein, we report incorporation of chloromethyl moieties into a living diatom to prepare an alkyl-halide activated siliceous biotemplate. Subsequent, in situ polymerization via surface initiated atom transfer radical polymerization generated a polymer/silica microparticle with defined geometry. 2015-01-01T00:00:00Z