Reconstruction of Ablated Rat Rectus Abdominis by Muscle Regeneration

Abstract

Skeletal muscle regeneration is a powerful, naturally occurring process of tissue reconstruction that follows myofiber damage secondary to myotoxic injury that does not normally affect the tissue circulation and scaffold. The ablated tissue, in traumatology and free muscle grafts, is frequently replaced by scars. The final outcome is poor even after in situ myoblast seeding of the harvested muscle. The goal of this study was to identify protocols to reconstruct muscle tissue, even in such adverse environments. The authors applied a step-by-step approach to identify factors favoring the survival of autologous satellite cells and, thus, muscle regeneration. In a rat model of full-thickness rectus abdominis muscle ablation, autologous myoblasts were isolated from the explanted rectus abdominis and seeded in a homologous acellular matrix immediately after wall reconstruction (group 1, five animals). In group 2 (five animals), the ablated rectus abdominis was autografted in situ. In a third group of five rats, Marcaine was injected into both the autograft and the surrounding abdominal wall muscle. Three weeks after surgery, serial cross-sections of the reconstructed abdominal wall were stained with hematoxylin and eosin or embryonic myosin antibody, a well-characterized molecular marker of early myogenesis in development and regeneration. Percentages of the patch area covered by regenerated myofibers were determined by morphometry. When autologous myoblasts were seeded in a homologous acellular matrix, the only myofibers observed to regenerate were those along the border of the patch. Autografting of the middle third of the rectus abdominis muscle similarly resulted in scar formation. The few muscle cells in the graft core were scanty myoblasts that could be detected only by monoclonal embryonic myosin antibody. Although negative for myofiber regeneration, the results in both cases confirmed the mechanical patency of the patches with regard to abdominal organ support. Myofibers were successfully regenerated in the graft by injecting Marcaine into both the autograft and the surrounding muscles. Three weeks after surgery, the patch was paved with young, centrally nucleated myofibers intermixed with young myofibers and myotubes expressing embryonic myosin. The difference in percentage of patch area covered by regenerated myofibers in group 3 (Marcaine injection around the patch, 81.6 +/- 3.0 percent) (mean +/- SD) versus either group 1 (Myoblast-seeded acellular patch, 18.0 +/- 3.0 percent) or group 2 (Autograft, 25.8 +/- 7.0 percent) was statistically significant on independent t test analysis (p < 0.0001). Even an acellular matrix showed some myofiber regeneration after surrounding muscles had been injected with Marcaine. This is the first successful evidence of muscle reconstruction after full-thickness ablation of the middle third of the rectus abdominis. Muscle regeneration seems to be the result of successive waves of migration of angioblasts and then satellite cell-derived myoblasts from the muscles surrounding th...

Regeneration of skeletal muscle

“…Moreover, evidence suggests that the procedures used for isolation and in vitro expansion can cause satellite cells to lose their regenerative capacity (Renault et al 2000;Sherwood and Wagers 2006;Montarras et al 2005), with some suggesting the use of muscle grafts to provide a satellite cell population rather than enzymatic isolation techniques (Montarras et al 2005;Collins and Zammit 2009;Mong 1988;Schultz et al 1988). Despite these problems, a number of examples of satellite cell transplantation have led to the successful restoration of muscle injuries (Alameddine et al 1989;Alameddine et al 1994;el Andalousi Boubaker et al 2002;Li et al 2010;Marzaro et al 2002;Vindigni et al 2004). …”

“…The seeding of an ECM scaffold with myogenic progenitor cells, followed by transfer to an in vivo site, allows the full development of myotubes and functional muscle tissue to occur (Liao and Zhou 2009;Borschel et al 2004;du Moon et al 2008;Vindigni et al 2004;Beier et al 2009;Merritt et al 2010). However, these in vitro techniques generally produce muscle with small contractile forces, since the amount of scaffold material is high and can inhibit myoblast fusion.…”

Brain Tumors: Role of Neural Cancer Stem Cells

“…The ontogenesis of these EPCs is unclear, however they may derive from putative hemangioblasts which are the precursors of both hematopoietic and endothelial cell lineages (Vindigni et al, 2004). These hemangioblasts express phenotypic markers of hematopoietic stem cells (HSCs) and differentiated endothelial cells, CD34/Flk-1 (Vindigni et al, 2004) and are difficult to distinguish from EPCs. Once in peripheral blood they home to sites of tumor growth, where they differentiate into endothelial cells to support vascular remodeling (Asahara et al, 1999).…”

“…It has been shown that BM-derived endothelial progenitor cells (EPCs) as the leading cellular component in tumor angiogenesis (Lyden et al, 2001). The ontogenesis of these EPCs is unclear, however they may derive from putative hemangioblasts which are the precursors of both hematopoietic and endothelial cell lineages (Vindigni et al, 2004). These hemangioblasts express phenotypic markers of hematopoietic stem cells (HSCs) and differentiated endothelial cells, CD34/Flk-1 (Vindigni et al, 2004) and are difficult to distinguish from EPCs.…”

Jejunal Flap as an In Vivo Vascular Carrier for Transplanted Adipose Tissue

“…Until now, successes have been restricted to relatively thin or avascular structures (for example, skin and cartilage), where postimplantation neovascularization from the host is sufficient to meet the implant's demand for oxygen and nutrients. [4][5][6][7][8] Few manuscripts describe the construction of an adipose tissue composite flap that could be used to reconstruct volume-significant soft tissue lost to cancer, trauma, or deep burn. 9 -13 In particular, as surgical mastectomy or lumpectomy for treatment of breast cancer is frequently performed, there is a significant need for breast reconstruction.…”