Abstract 5586: Catestatin Induces Therapeutic Neovascularization by Induction of Angiogenesis and Incorporation of Endothelial Progenitor Cells
Introduction Catestatin (Cat), a biologically active fragment of Chromogranin A was described as a nicotinic antagonist inhibiting catecholamine release. Recently, also other biological effects for this peptide were described like release of histamine or activation during cutaneous wounds. We found that Cat induces chemotaxis on a variety of cells including endothelial cells (EC) and therefore hypothesized that Cat might act as a novel angiogenic cytokine.
Results To investigate the effect of Cat on EC differentiation into vascular structures in vitro, we performed a matrigel tube formation assay using different concentrations of Cat. Cat at 10−9M was most effective in promoting tube formation (rel. tube form. 1.77+/−0.08 vs. ctr.; n=4, P<0.01). This effect could be blocked by a Cat antibody (Ab) (0.87 +/−0.1 vs. ctr; n=4, P<0.01 vs. Cat). Additionally, Cat dose-dependently induced chemotaxis of EC (rel. chemotact. index 10−9M: 1.67+/−0.03 vs. ctr; n=6, P<0.01) and promoted EC proliferation as measured by cell numbers of starved EC (rel. cell number 10−9M: 1.86 +/−0.13 vs. ctr., n=4, P<0.01; Cat-Ab 0.97+/−0.06 vs. ctr; n=4, P<0.05 vs. Cat). Western blot analysis revealed stimulation of ERK and AKT by 10−9M Cat indicating activation of these signal transduction pathways. We also tested for angiogenic effects in vivo by using 3 different mouse models. In the mouse cornea neovascularization model Cat induced significant growth of new blood vessels. In the unilateral limb ischemia model injection of Cat (10 μg every other day for 2 weeks) into adductor muscles increased capillary (475+/−31 vs. 303+/−28/mm2; n=7, P=0.003) and arteriole (10.1+/−0.8 vs. 5.2+/−1.0/mm2; n=7, P=0.001) density, and accelerated perfusion recovery as shown by LDPI (LDPI ratio ischemic/control leg after 28 days of ischemia) 0.94 vs. 0.74; n=10, P=0.009. Moreover, Cat treated mice showed more incorporated EPC in ischemic limbs using the actin-GFP bone marrow transplant model (21.7+/−2.2 vs. 9.6+/−2.1; n=6, P<0.001).
Conclusion In summary our observations demonstrate that Cat therapy induces angiogenesis, arteriogenesis and vasculogenesis in the hind-limb ischemia model suggesting that Cat might be a promising agent for therapeutic angiogenesis in peripheral arterial disease.