Growth, differentiation, transplantation and survival of human skeletal myofibers on biodegradable scaffolds

Abstract

Skeletal muscle transplantation strategies for muscle repair or gene therapy involve either the injection of proliferating myoblasts followed by fusion with host myofibers or implantation of ex vivo differentiated myofibers; however, both implant procedures are associated with significant cell loss. Biodegradable porous, gas-foamed poly-lactide-co-glycolide (PLG) scaffolds have desirable characteristics for cell transfer and were used to study attachment, growth, differentiation and survival of human myogenic cells. Primary human myoblasts suspended in clinical grade extracellular matrixes (ECMs) and adhered to PLG scaffolds differentiated in vitro into high-density tropomyosin positive myofibers. An immunodeficient non-obese diabetic/severe combined immunodeficiency (NOD/SCID) mouse implant model was used to study the transfer and in vivo survival of differentiated human myofibers on these scaffolds. Scaffold rigidity allowed the myofibers to be maintained under tension in vitro and following subcutaneous transplantation in vivo. Following implantation, myofiber density on the PLG scaffolds decreased linearly by 78% over a 4-week period. ECM composed of either Tisseel s fibrin or Zyderm s collagen type I did not significantly affect in vivo cell viability over the 4-week period. Varying PLG scaffold microsphere content (10-100%) also had little effect on cell survival in vivo. In contrast, when the residual NK cell population in the immunodeficient NOD/SCID mouse model was depleted with anti-asialo GM1 (ASGM1) antiserum, in vivo cell survival significantly increased from 22% to 34% after 4 weeks. With further improvements in cell survival, PLG scaffolds may prove useful for the implantation of primary human myofibers in future clinical applications. r

Endothelial Network Formation Within Human Tissue-Engineered Skeletal Muscle

“…Parallel alignment of the myofibers can be induced when cells are subjected to a unidirectional force during differentiation and results in functional bioartificial muscles (BAMs), which can be electrically and mechanically stimulated. [4][5][6] However, the size of in vitro created skeletal muscle tissue is limited due to the lack of a vascular network in vitro. Coculturing endothelial cells and myoblasts, muscle precursor cells, might overcome this problem.…”

Colonization and Osteogenic Differentiation of Different Stem Cell Sources on Electrospun Nanofiber Meshes

“…Therefore, if cells are seeded throughout a 3D scaffold and placed at the defect site, cells located at the center of the scaffold may not survive. 16,17,49,50 Delivery of cells on the periphery of bone defects via a tissueengineered periosteum may be an effective approach to enhance cell survival by the presence of a neighboring vasculature. With time, as a continuous vasculature is established at the center, the cells may migrate toward the center due to an improved transport environment.…”

“…This presents a very harsh environment that makes cell survival extremely difficult. 16,17 An alternative is to deliver cells to the periphery of the defect via a thin membrane or scaffold. This delivery strategy may enhance cell survival by positioning the cells in proximity to the surrounding highly vascularized tissues, and thereby providing for nourishment and clearance of waste products.…”

In vitro growth and differentiation of primary myoblasts on thiophene based conducting polymers

“…A number of reports have highlighted the diversity of approaches that have been applied to improve skeletal muscle engineering, including the use of micro-patterned polymers [5][6][7], biological scaffolds [8] and synthetic polymers [9][10][11][12][13]. Synthetic scaffolds have the advantage over biologic scaffolds in that their characteristics can be defined and manipulated to be inherently pro-myogenic (i.e.…”