Abstract 14712: Nanopatterned Extracellular Matrices Promote Endothelial Sprouting and Arteriogenesis in a Murine Model of Peripheral Arterial Disease
Peripheral arterial disease (PAD) affects over 8 million patients in the US and is characterized by limb ischemia, in part due to dysfunction of vascular endothelial cells (ECs). Approaches to enhance angiogenesis and arteriogenesis so as to improve blood flow are promising. Since cells physiologically respond to nano-scale extracellular matrix (ECM) cues, we hypothesized that nanopatterned scaffolds will promote vascular regeneration. We fabricated collagen nanofibrillar scaffolds that were either randomly oriented or parallel-aligned. Primary human ECs cultured on the aligned scaffolds with 30-nm fibril diameters realigned their actin assembly along the nanofibril direction, whereas cells on the randomly oriented scaffolds adopted a random distribution of actin. When cell-seeded scaffolds were encapsulated within three-dimensional hydrogels, the ECs from the aligned scaffolds showed increased outgrowth than cells from randomly oriented scaffolds. To test the efficacy of aligned nanofibrillar scaffolds in improving neovascularization in an experimental model of PAD, we induced unilateral hindlimb ischemia in SCID mice by excising the femoral artery. The mice received one of the following treatments at the site of the excised femoral artery: 1) human EC-seeded aligned nanofibrillar scaffold; 2) EC-seeded non-patterned scaffold; 3) ECs in saline; 4) aligned nanofibrillar scaffold alone; or 5) no treatment. After 14 days, laser Doppler blood spectroscopy demonstrated significant improvement in blood perfusion in the group treated with cell-seeded aligned nanofibrillar scaffolds, in comparison to the groups with no treatment or EC delivery in saline. In similar experiments performed using human ECs derived from induced pluripotent stem cells (iPSC-ECs), we further compared arteriogenesis using intravital near infrared-II fluorescence microscopy for imaging arterioles and larger vessels. Our results on day 28 showed that within the ischemic limb, the iPSC-EC-seeded aligned scaffolds showed significantly higher microvascular density than the treatment group that received cells in saline. Together, these studies demonstrate that ECs cultured on the aligned nanofibrillar scaffolds augmented blood perfusion and arteriogenesis.
Author Disclosures: N.F. Huang: Research Grant; Modest; Department of Defense, National Institutes of Health, Veterans Affairs Merit Award. K.H. Nakayama: None. G. Hong: None. J. Patel: None. B. Edwards: None. T.S. Zaitseva: Employment; Modest; Fibralign Corp. M.V. Paukshto: Employment; Modest; Fibralign Corp. H. Dai: None. J.P. Cooke: None. Y.J. Woo: None.
- © 2014 by American Heart Association, Inc.