Angiogenic response to extracorporeal shock wave treatment in murine skin isografts

Abstract

Skin grafts are commonly utilized and proven effective methods of open wound coverage. Revascularization through neoangiogenesis is a pivotal mechanism for skin graft integration and durability. Extracorporeal shock-wave treatment (ESWT) has been demonstrated to accelerate wound repair; however, its mechanism-of-action is unclear. We investigated the role of ESWT in early revascularization of full-thickness skin isografts in a murine model. Cohorts of mice were euthanized and skin grafts were harvested 6 h, 2, 4, and 7 days post grafting +/- ESWT. Various aspects of graft neovascularization were measured including gross morphology, quantitative microscopy (vessel number, density), immunohistochemistry (CD31), cDNA SuperArrays for 84 angiogenesis-specific genes, and custom-designed 'Wound Repair' TaqMan Low Density Array (TLDA) cards to assess expression of 188 wound repair genes. We demonstrate that a single administration of ESWT immediately following skin grafting significantly enhances recipient graft revascularization (increased vessel number, size, and density). An augmented early pro-angiogenic and suppressed delayed pro-inflammatory response to ESWT was accompanied by significantly increased expression of both skin graft CD31 and angiogenesis pathway-specific genes, including ELR-CXC chemokines (CXCL1, CXCL2, CXCL5), CC chemokines (CCL2, CCL3, CCL4), cytokines (IL-1 beta, IL-6, G-CSF, VEGF-A), matrix metalloproteinases (MMP3, MMP9, MMP13), hypoxia-inducible factors (HIF-1 alpha), and vascular remodeling kinase (Mst1), as early as 6 h and up to 7 days post grafting and treatment. These findings suggest that early pro-angiogenic and anti-inflammatory effects of ESWT promote tissue revascularization and wound healing by augmenting angiogenesis and dampening inflammation.

Shock Wave Treatment Enhances Cell Proliferation and Improves Wound Healing by ATP Release-coupled Extracellular Signal-regulated Kinase (ERK) Activation

“…Our in vivo experiments demonstrated that the biological responses triggered by ESWT improved tissue repair. It remains to be seen to what extent the here proposed mechanism induced by ESWT also influences other aspects of wound healing such as neovascularization, angiogenesis, stem cell differentiation, and the inflammatory response involved in wound repair as shock wave treatment already has been reported to favor these phases of wound healing (2,10,12,19,60). Our in vivo studies further revealed that ESWT improves wound healing in a rat ischemic skin flap model and that Erk1/2 signaling is involved in this process.…”

“…ESWT was shown to augment the expression of proliferating cell nuclear antigen and the recruitment of fibroblasts and to down-regulate production of proinflammatory cytokines (16). Other studies have shown that the expression of certain cytokines, chemokines, and matrix metalloproteinases with proangiogenic roles is enhanced during ESWT-promoted wound healing (12).…”

“…In recent years, various research groups have focused on the angiogenic impact of shock waves (4,5,12,13). They have shown that ESWT up-regulates angiogenesis via mediators such as vascular endothelial growth factor (VEGF), endothelial nitric-oxide synthase, hypoxia-inducible factor 1a, and CD31 (4,5,14,15).…”

Early Characterization of Blast-related Heterotopic Ossification in a Rat Model

“…Consistent with the finding of Peterson et al, removal of ATP using apyrase inhibited ESWT-induced osteogenic differentiation. ESWT has been used in treatment of bone and soft tissue disorders and shown to stimulate soft tissue expression of osteogenic factors (BMPs, OC, OPN, TGFb1) but also angiogenic factors (VEGF, FGF) [27,32]. Therefore, it is not surprising that many of the genes induced in the musculature of the injured limb show parallel, albeit reduced, levels of change in the contralateral limb.…”

Extracorporeal Shock Wave Therapy as a New and Non-invasive Angiogenic Strategy

“…Recently, several studies are reported that showed the beneficial effects of low-energy SW therapy in other disorders, including skin flap model in rodents (Stojadinovic et al 2008;Yan et al 2008) and patients with refractory chronic skin ulcers (Saggini et al 2008;Moretti et al 2009). Also, low to high energy levels of SW is widely used for the treatment of certain orthopedic conditions, such as nonunions, tendinosis calcarea, epicondylitis and calcaneal spur (Birnbaum et al 2002;Wang et al 2003).…”