Myoblasts enhance collateral capillary arteriogenesis during chronic ischemia

Abstract

Peripheral arterial occlusive disease (PAOD) involves peripheral artery occlusion, which causes ischemia (i.e. insufficient blood flow) and is the leading cause of amputation. Natural bypass vessels known as collaterals can preserve downstream tissue viability by creating an alternative route for blood flow. Increased blood flow through preexisting collateral increases shear stress and triggers arteriogenesis, the outward remodeling of arterial vessels. The presence of collaterals improves prognosis in patients with ischemic disease, but many patients never develop identifiable collaterals to relieve peripheral ischemia. Animal models that lack preexisting collaterals are capable of forming collaterals from capillaries that undergo arteriogenesis to become arterialized capillary collaterals (ACC). A treatment to induce the formation of ACCs, particularly in diseased or aged tissues that lack the propensity to form new collateral vessels, could be highly effective in giving protection against ischemia. Exercise is a great therapy for PAOD, since following exercise, resident muscle stem cells known as satellite cells (SCs) activate and regulate local angiogenesis. SCs and their progeny myoblasts secrete factors known to be involved in arteriogenesis (many of these compounds involved in angiogenesis are also involved in arteriogenesis) and the recruitment of other cells involved in remodeling. Therefore, transplanting these putative arteriogenic cells is a potential therapy to recapitulate some of the beneficial effects of exercise therapy. In this study, the lateral feed artery in the spinotrapezius muscle of Balb/C mice was ligated to induce chronic ischemia; myoblasts were transplanted during surgery to enhance arteriogenesis of collateral capillaries. Implanted mice exhibited increased arteriogenesis, ACC diameter increased to 28.11 ± 0.85 μm vs 16.25 ± 0.62 μm in a no transplant control. As corollary, we evaluated the process for cell construct preparation and discovered that cells cultured on scaffold overnight (20.86 ± 1.6 μm) before transplant did not stimulate arteriogenesis as significantly as those who were cultured for 6‐hours only. Limited nutrient supply and gas exchange while incubating on scaffolds could induce stress on myoblast and cause limited reactivity/apoptosis post implant. In summary, myoblast transplantation increases ACC arteriogenesis; however, they need to be transplanted as early as possible post‐harvest from culture flask.Support or Funding InformationFunding: CIRM ( California Institute for Regenerative Medicine)This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.