Abstract 19789: Specifically Designed, Bioactive Nanofiber-Matrix Supports Cell-based Therapy in Ischemic Tissue Repair
The therapeutic use of stem and progenitor-based therapy for ischemic tissue repair is limited: Cells from cardiovascular patients are prone to apoptosis, are dysfunctional, cell viability and retention poor, and detachment from native extracellular matrix favors cells death. Bionanotechnology enables development of specifically designed biomaterials to address these limitations and may enhance efficacy of cell-based therapy by providing bioactive microenvironment. Given the importance of integrin-signaling for cellular homeostasis, we designed a self-assembling peptide amphiphile (PA) nanofiber that presents the integrin-binding domain of fibronectin (RGDS-PA). Incubation of BM-derived pro-angiogenic cells (BMPAC) with RGDS-PA (0.2w%) reduced H2O2-induced apoptosis compared to untreated cells (TUNEL+/TUNEL- cells: control 0.60±0.07, RGDS-PA: 0.22±0.02; n=5–10, P<0.01), increased cell proliferation (MTS assay: control 100%, RGDS-PA 174±30%; n=7–12, P<0.01), and enhanced adhesion to uncoated (control 59±25, RGDS-PA 185±95, P<0.05) and vitronectin coated surfaces (control 53±26, RGDS-PA 201±84, P<0.05). Tube formation (matrigel assay) and migration (Boyden chamber), endpoints that integrate several cell functions, were enhanced and impaired, respectively. Combining a sub-therapeutic dose of 105 BMPAC with RGDS-PA (R/B) for local injection after surgical hind-limb ischemia (HLI) in 8-week-old, male FVB/N mice, improved blood flow recovery (laser Doppler, ischemic/non-ischemic limb ratio: R+B, 0.67±0.06; B, 0.55±0.04), limb salvage (score: R+B, 3.4±0.3; B 2.9±0.4; n=8–9/group, P<0.05), and motor function of the ischemic limb (score: R+B, 3.6±0.2; B, 2.9±0.2; n=8–9/group, P<0.05) compared to BMPAC alone (B) at day 28. These findings are associated with more CD31+ capillaries in the ischemic limb muscle (control 56±2/hpf, R+B: 91±5/hpf, B: 72±2/hpf; n=5–9/group, p<0.001). Tracking of β-actin-luc+ cells revealed higher bioluminescent signals, reflecting more viable cells at day 7 (R+B, 692±141%; B, 132±50%; n=7–9/group, p<0.01).
Conclusion: Self-assembling nanofibers presenting the integrin-binding domain of fibronectin support transplanted cells in ischemic tissue and enhance their therapeutic potency.
- © 2010 by American Heart Association, Inc.