Regenerative medicine: Basic concepts, current status, and future applications
ABSTRACT A recent report demonstrated that a laboratory-grown neobladder tissue could be successfully used for cystoplasty in young patients with myelomeningocele who were otherwise healthy. This remarkable achievement portends well for the application of tissue engineering/regenerative medicine technologies to the treatment of end-organ failure due to a variety of causes (ie, congenital, acquired, age or disease related). Nonetheless, the broader clinical use of these groundbreaking technologies awaits improved understanding of endogenous regenerative mechanisms, more detailed knowledge of the boundary conditions that define the current limits for tissue repair and replacement in vivo, and the parallel development of critical enabling technologies (ie, improved cell source, biomaterials, bioreactors). This brief report will review a number of the most salient features and recent developments in this rapidly advancing area of medical research and detail some of our own experience with bladder and skeletal muscle regeneration and replacement as examples that highlight both the promise and challenges facing regenerative medicine/tissue engineering.
- SourceAvailable from: Deborah M Grzybowski
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ABSTRACT: Endothelial progenitor cells (EPCs) are a promising cell source for vascular tissue engineering approaches in surgery. Diverse biomaterials have been used as matrices for EPC cultivation. In this in vitro study, fibrin in combination with growth factors was examined as an optimized culturing scaffold for EPCs. EPCs were isolated from peripheral blood by density gradient centrifugation and positive selection using CD34-specific magnetic beads. Cells were seeded on fibrin for 3, 5, and 10 days or on fibronectin for control purposes. The growth factors erythropoietin (EPO), granulocyte-monocyte colony-stimulating factor (GM-CSF), and hepatocyte growth factor were added as indicated. Cell proliferation and integrity measurements were performed, and EPC differentiation was determined by fluorescence-activated cell sorting (FACS) analysis. EPCs cultured on fibrin showed a significantly higher proliferation rate and suffered less from matrix-induced cell death compared to EPCs cultured on fibronectin. Additionally, fibrin was a stronger stimulus for the differentiation of EPCs into a mature endothelial phenotype, as revealed by the expression of adult endothelial markers by FACS analysis. Moreover, EPO and GM-CSF enhanced EPC proliferation and differentiation to a greater extent when EPCs were grown on fibrin. We conclude that EPC cultivation on fibrin is superior compared to the commonly used fibronectin as a scaffold for tissue engineering of vascular structures. The addition of different growth factors, reported to stimulate EPC growth, further improves the beneficial effects of this matrix.Langenbeck s Archives of Surgery 08/2011; 396(8):1255-62. DOI:10.1007/s00423-011-0839-y · 2.16 Impact Factor
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ABSTRACT: Chitosan is widely used as a scaffold for bone tissue engineering. However, up-to-date, no previous detailed study has been conducted to elucidate any mechanism of osteogenesis by chitosan itself. Here, we have evaluated effects of chitosan-coated tissue culture plates on adhesion and osteoblast differentiation processes of human mesenchymal stem cells (hMSCs), isolated from adult bone marrow. Tissue culture plates coated with chitosan at different coating densities were used to evaluate the effects on hMSC adhesion and osteoblast differentiation. hMSCs were induced to differentiate into osteoblasts on the chitosan-coated plates and were evaluated using established techniques: alkaline phosphatase assay, demonstration of presence of calcium and real time PCR. The cells adhered to plates of lower coating density of chitosan, but formed viable cell aggregates at higher coating density (100 μg/sq.cm). Coating density of 25 μg/sq.cm, supporting cell adhesion was chosen for osteoblast differentiation experiments. Differentiating hMSCs showed higher mineral deposition and calcium content on chitosan-coated plates. Chitosan upregulated genes associated with calcium binding and mineralization such as collagen type 1 alpha 1, integrin-binding sialoprotein, osteopontin, osteonectin and osteocalcin, significantly. We demonstrate for the first time that chitosan enhanced mineralization by upregulating the associated genes. Thus, the study may help clinical situations promoting use of chitosan in bone mineralization, necessary for healing non-union fractures and more.Cell Proliferation 12/2011; 44(6):537-49. DOI:10.1111/j.1365-2184.2011.00788.x · 3.28 Impact Factor