Fragmin/protamine microparticles as cell carriers to enhance viability of adipose‐derived stromal cells and their subsequent effect on in vivo neovascularization

Abstract

We prepared fragmin/protamine microparticles (F/P MPs) as cell carriers to enhance cell viability. Use of material consisting of a low-molecular-weight heparin (fragmin) mixed with protamine resulted in water-insoluble microparticles (about 0.5-1 microm in diameter). In this study, we investigated the capability of F/P MPs to enhance the viabilities of human microvascular endothelial cells (HMVECs), human dermal fibroblasts (fibroblasts), and adipose tissue-derived stromal cells (ATSCs) in suspension culture. F/P MPs were bound to the surfaces of these cells, and the interaction of these cells with F/P MPs induced cells/F/P MPs-aggregate formations in vitro, and maintained viabilities of those cells for at least 3 days. The ATSCs/F/P MPs-aggregates adhered to and grew on suspension culture plates in a fashion similar to those on type I collagen-coated plates. The cultured ATSCs secreted significant amounts of angiogenic heparin-binding growth factors such as FGF-2. When the ATSCs/F/P MPs-aggregates were subcutaneously injected into the back of nude mice, significant neovascularization and fibrous tissue formation were induced near the site of injection from day 3 to week 2. The ATSCs/F/P MPs-aggregates were thus useful and convenient biomaterials for cell-therapy of angiogenesis.

Efficacy of fragmin/protamine microparticles containing fibroblast growth factor-2 (F/P MPs/FGF-2) to induce collateral vessels in a rabbit model of hindlimb ischemia

“…1,9 In addition, clinical studies have revealed good results following direct injection of naked plasmid DNA encoding human VEGF or recombinant growth factors. However, their performance is limited by high cost.…”

“…The F/P MPs used in this study were about 0.5 to 3 m in diameter, and the F/P MPs (200 L) subcutaneously injected into mice visually disappeared within 2 weeks. 8,9 Animal model of hindlimb ischemia. The present study used a rabbit model of hindlimb ischemia in all experiments.…”

“…7,8 In addition, introductions of bone marrow cells or adipose-derived stromal cells and direct injection of naked plasmid DNA encoding human VEGF or recombinant growth factors have a potential to induce angiogenesis. 1,9 Although some of those studies have revealed good results, their performance is limited by high cost. 7,9 Two forms of vessel growth "angiogenesis and arteriogenesis" are observed after birth.…”

“…1,9 Although some of those studies have revealed good results, their performance is limited by high cost. 7,9 Two forms of vessel growth "angiogenesis and arteriogenesis" are observed after birth. 10,11 Angiogenesis is defined as the formation of new capillaries by sprouting and arteriogenesis as the growth of collateral arteries.…”

Attenuation of Limb Loss in an Experimentally Induced Hindlimb Ischemic Model by Fibroblast Growth Factor-2/Fragmin/Protamine Microparticles as a Delivery System

“…In this study, only mature vessels containing erythrocytes were counted. 6,32 Statistical analyses Statistical analysis was carried out by repeated-measures analysis of variance using the means and standard deviations for each experimental group. Scheffe's post hoc test was used for multiple comparisons, and p < 0.05 was considered statistically significant.…”