Significant Angiogenic Potential is Present in the Microenvironment of Muscle Flaps in Humans

Abstract

The purpose of this study was to determine the presence of growth factors and the quality of angiogenic potential in the wound microenvironment in different types of flaps in humans. The wound exudates from 23 flaps were processed for analysis of transforming growth factor beta1 (TGF-beta1), epidermal growth factor (EGF), interleukin 1alpha (IL-1alpha), platelet-derived growth factor-AB (PDGF-AB), vascular endothelial growth factor (VEGF), and insulin-like growth factor (IGF-1) by enzyme-linked immunosorbent assay (ELISA) or radio immuno assay (RIA). Angiogenic activity of wound fluid from latissimus flaps was determined by thymidine incorporation in porcine microendothelial cells exposed to various concentrations of wound fluid and control media. Angiogenic and matrix growth factors were altered in a linear fashion during the wound-healing process. Regression analysis provided evidence for decreasing levels of PDGF and EGF for latissimus flaps. Also, statistically significant differences of growth factor levels were found for paired comparison of flap types at different times after operation. Growth of in-vitro endothelial cells was stimulated most by 10 percent wound fluid, compared to any of the individual recombinant angiogenic factors or combinations of these factors. The data suggest that vascularized tissue flaps will promote wound healing by providing sufficient sources of growth factors in the wound environment. The particular type of flap, i.e., muscle or fasciocutaneous flap, does not seem to have an impact on growth-factor expression.

The skeletal muscle secretome: an emerging player in muscle–bone crosstalk

“…First, it is clear that intact muscle flaps are a rich source of secreted growth factors. 20 Second, although muscle does provide important vascular support for bone, skin has a higher vascular density than muscle, yet fasciocutaneous skin flaps do not have the same anabolic effects on healing bone as muscle flaps. 21 Third, it is clear that conditioned medium from cultured muscle cells has positive effects (for example, increasing extracellular matrix synthesis) on cultured chondocytes, 22 revealing that muscle is a source of secreted growth factors both in vivo and in vitro .…”

“…Wound exudates from intact muscle flaps contain high levels of IGF-1, 20 and immunohistochemistry has been used to localize IGF-1 along the muscle-periosteal interface of mouse forelimbs. 25 These in vivo findings are consistent with in vitro studies in which proteomic approaches have been used to detect IGF-1 in conditioned medium from cultured myotubes.…”

Pulsed Electromagnetic Fields Reduce Postoperative Interleukin-1β, Pain, and Inflammation

“…The concentration of interleukin-1β in the wound exudates collected in the study is consistent with that reported in other studies. [31][32][33][34][35] The pulsed electromagnetic field effect on the dynamics of interleukin-1β in wound exudates correlate well with the rapid decrease of postoperative pain in patients in the active cohort.…”

Plastic Surgery Challenges in War Wounded I: Flap-Based Extremity Reconstruction

“…9,10,27,28 Muscle flaps have also been shown to promote bone repair secondary to a greater amount of osteogenic mesenchymal stem cells and bone anabolics such as interleukin-6 and fibroblast grow factor-2. 29,30 Multiple animal studies have demonstrated the importance of muscle coverage on fracture sites, although tissue transfer has not been directly examined within these studies. [9][10][11]31 Retrospective reviews of patients with open tibia fractures show that muscle flaps can reduce healing time and decrease infection and necrosis rates compared with fasciocutaneous flaps.…”