Jonathan Kent Leach
University Of California Davis
Project start date: 2011-03-01
Project end date: 2013-02-28
Sponsored Links Excellgen http://Excellgen.com
Grants awarded to Jonathan Kent Leach
PHOSPHOLIPIDS FOR ENHANCING CELL-BASED NEOVASCULARIZATION
Jonathan Kent Leach, Assistant Professor
University Of California Davis, Office Of Research - Sponsored Programs, Davis, Ca 95618
Grant 1R21AG036963-01A1 from National Institute On Aging
Abstract: The reduction of oxygen occurring as a result of advanced vascular diseases poses severe clinical problems including massive cell death and resultant tissue loss. Compared to pharmacological methods of therapeutic angiogenesis, cell-based strategies represent a direct approach to generate a capillary network. Endothelial colony forming cells (ECFCs) are a subpopulation of endothelial progenitor cells that exhibit robust angiogenic potential under hypoxic conditions and can form functional vascular networks in vivo. Adipose- derived stem cells (ASCs) are a promising cell population for promoting angiogenesis and potentially stabilizing new vessels. However, the success of cell-based therapies is limited by rapid cell death due to apoptosis upon implanting cells into ischemic tissue environments, dramatically reducing the number of cells available to participate in vasculogenesis. Additionally, recent data suggest that cells derived from older donors are more vulnerable to apoptosis than those from younger donors, potentially compromising the effectiveness of autologous cell-based approaches for tissue repair in the ever-growing aging population. Lysophosphatidic acid (LPA) is a platelet-derived lipid growth factor present within the serum and is required for angiogenesis in vivo. Additionally, LPA promotes the survival and viability of progenitor cells within pro-apoptotic microenvironments in vitro. Our central hypothesis is that localized and sustained presentation of LPA will be an effective agent to inhibit apoptosis in implanted cells, thus enabling prolonged secretion of trophic factors from cells and supporting the survival of vessel-forming cells. The rationale for this project is that it will provide new insights into the role of the oxygen microenvironment and how progenitor cells participate in tissue repair, and yield new approaches for enhancing the efficacy of tissue repair with cells from aged donors. Aim 1. Determine the anti-apoptotic and proangiogenic effect of sustained LPA release on co-cultures of human ECFCs and ASCs within fibrin gels. The ability of localized LPA release to inhibit apoptosis in hypoxic and serum-reduced conditions will be assessed, and the resulting vasculogenic response to these stimuli will be quantified. Aim 2. Determine the capacity of ASCs derived from aged donors and ECFCs to resist apoptosis and enhance vascularization when co-implanted on LPA-eluting materials into a murine ischemic hind limb model. The proposed research is innovative because it examines a novel approach for addressing the loss of cells implanted for neovascularization while investigating the role of multiple stimuli on vessel formation critical for the clinical translation and realization of these approaches. We will elucidate the contributions of LPA delivery on extending the viability of ASCs from older donors when implanted into an ischemic tissue site characteristic of advanced vascular disease. Collectively, this research will provide a novel approach for enhancing the efficacy of implanted cells for cell-based therapies for tissue repair, wound healing, and emerging applications in tissue engineering and regenerative medicine. The development of new approaches to enhance cell viability and function upon implantation will greatly improve the quality of life for those who suffer from advanced vascular disease or non-healing tissue defects. We seek to determine if the localized presentation of a phospholipid can inhibit apoptosis in implanted vessel- forming cells, thereby resulting in prolonged survival and enhanced neovascularization
Keywords: 1-acyl-sn-glycerol-3-phosphate; 1-oleoyl-lysophosphatidic acid; Address; Adipocytes; Adipose Cell; Adipose tissue; Affect; Age; Age Group Unspecified; Apoplexy; Apoptosis; Apoptosis Pathway; Apoptotic; Assay; Autologous; Bioassay; Biochemical; Biologic Assays; Biological Assay; Bioluminescence; Biosynthetic Proteins; Bizzozero`s corpuscle/cell; Blood Platelets; Blood Serum; Blood Vessels; Blood capillaries; Body Tissues; Capillaries; Capillary; Capillary, Unspecified; Cell Aging; Cell Count; Cell Death; Cell Death, Programmed; Cell Number; Cell Senescence; Cell Survival; Cell Therapy; Cell Viability; Cells; Cellular Aging; Cerebral Stroke; Cerebrovascular Apoplexy; Cerebrovascular Stroke; Cerebrovascular accident; Characteristics; Clinical; Co-culture; Cocultivation; Coculture; Coculture Techniques; Coronary Disease; Coronary heart disease; Data; Deetjeen`s body; Defect; Development; Effectiveness; Electromagnetic, Laser; Emergent Technologies; Emerging Technologies; Endothelial Cells; Environment; Exhibits; Extremities; Fat Cells; Fatty Tissue; Fibrin; GFAC; Gel; Growth Agents; Growth Factor; Growth Factors, Proteins; Growth Substances; Hayem`s elementary corpuscle; Healed; Human; Human, General; Hypoxia; Hypoxic; Image; Immunodeficient Mouse; Implant; In Vitro; Knowledge; LPA; Lasers; Light; Limb structure; Limbs; Lipids; Lipocytes; Lysophosphatidic Acids; Lysophospholipids; MOPA; Mammals, Mice; Man (Taxonomy); Man, Modern; Marrow platelet; Mature Lipocyte; Mature fat cell; Methods; Mice; Modeling; Mother Cells; Murine; Mus; Non-Trunk; O element; O2 element; Older Population; Oxygen; Oxygen Deficiency; Patients; Perfusion; Peripheral arterial disease; Phosphatides; Phospholipids; Photoradiation; Platelets; Population; Progenitor Cells; QOL; Quality of life; Radiation, Laser; Recombinant Proteins; Regenerative Medicine; Research; Reticuloendothelial System, Platelets; Role; Senescence, Cellular; Senescence, Replicative; Serum; Site; Stem cells; Stimulus; Stroke; Stromal Cells; Supporting Cell; Testing; Therapy, Cell; Thrombocytes; Tissue Engineering; Tissues; Translations; VEGFs; Vascular Accident, Brain; Vascular Diseases; Vascular Disorder; Vascular Endothelial Growth Factors; Vascularization; Vegf; Wound Healing; Wound Repair; adipose; age group; aged; aging population; angiogenesis; angiogenesis therapy; base; blood vessel disorder; brain attack; capillary; cell age; cell-based therapy; cerebral vascular accident; combat; coronary disorder; cost; density; dosage; engineered tissue; healing; imaging; implantation; improved; in vitro Assay; in vivo; innovate; innovation; innovative; insight; lysophosphatidic acid; molecular marker; monooleylphosphatidate; monooleylphosphatidic acid; necrocytosis; neovascularization; new approaches; novel; novel approaches; novel strategies; novel strategy; progenitor; public health relevance; response; social role; stem; stroke; success; therapeutic angiogenesis; thrombocyte/platelet; tissue repair; vascular; vasculogenesis; white adipose tissue; yellow adipose tissue
Relevance: Narrative The development of new approaches to enhance cell viability and function upon implantation will greatly improve the quality of life for those who suffer from advanced vascular disease or nonhealing tissue defects. We seek to determine if the localized presentation of a phospholipid can inhibit apoptosis in implanted vessel- forming cells, thereby resulting in prolonged survival and enhanced neovascularization
Project start date: 2010-07-01
Project end date: 2012-06-30
Budget start date: 1-JUL-2010
Budget end date: 30-JUN-2011
PFA/PA: PA-09-164
1R21AG036963-01A1 (2010): $188190
Sequential Release Of Growth Factors For Bone Formation
Jonathan Kent Leach
Harvard University 1350 Massachusetts Ave Cambridge, Ma 02138
Grant 1F32AR050928-01A1 from National Institute Of Arthritis And Musculoskeletal And Skin Diseases IRG: ZRG1
Abstract: In order to enhance tissue regeneration, two growth factors (VEGF and BMP-2) will be presented at a defect site by sequential release from a polymer scaffold. BMP-2 encoding plasmids will be presented by a scaffold containing incorporated VEGF. As the scaffold degrades, VEGF will be released to promote the invasion of new blood vessels into the implant, while BMP-2 plasmids will be transfected by neighboring mesenchymal cells to promote differentiation into osteoblasts and migration of osteoblasts into the implant for improved bone formation. As controlled by scaffold production, VEGF will be released prior to BMP-2 plasmids to allow for the initial vascularization of the implant, which provides transport of nutrients to migrating cells. The expression of BMP-2 will be sufficiently postponed to allow for neovascularization due to scaffold degradation and DNA transfection. In vitro release rates of each growth factor will be examined independently from each scaffold component as well as from the entire construct. The scaffold s ability to promote bone regeneration by sequential release of two growth factors will be examined in a critical defect model of the rat cranium. Vascularization and bone formation will be compared to several control groups.
Keywords: bone development, bone morphogenetic protein, vascular endothelial growth factor, angiogenesis, bone regeneration, cell migration, gene expression, head, osteogenesis, skull, enzyme linked immunosorbent assay, flow cytometry, gel electrophoresis, laboratory rat, photon absorptiometry, postdoctoral investigator, transfection
Project start date: 2004-09-15
Project end date: 2005-06-30
1F32AR050928-01A1 (2004): $42976