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GW24-e1275 Improved Biocompatibility of Poly (D, L-Lactide -Co-Glycolide) and Poly-L-lactic Acid Blended with Amorphous Calcium Phosphate in Rat Aortas and Rabbit Iliac Arteries
  1. Zheng Xiaoxin,
  2. Xuejun Jiang
  1. Cardiovascular Division, Renmin Hospital of Wuhan University, Wuhan, China

Abstract

Objectives Polyesters are the major polymers used in coating or making biodegradable stent, but with issues of inflammation response and insufficient radial strength. We hypothesise blending Poly (D, L-Lactide-Co-Glycolide (PLGA) and Poly-L-lactic acid (PLLA) with Amorphous calcium phosphate (ACP) might solve the problems. The purpose of this study is to investigate the biocompatibility of PLGA/ACP and PLLA/ACP composite in vivo.

Methods Metal stents were coated with either polyethylene-co-vinyl acetate/poly-n-butyl methacrylate (PEVA/PBMA), PLGA and PLGA/ACP composite, respectively, and implanted into rat aortas for one and three months. In addition, PLLA/ACP and PLLA polymers were extruded into stent tubes and implanted into rabbit iliac arteries for one month.

Results At one month, stents coated with PLGA/ACP group had significantly lower percentage of restenosis and arterial inflammatory score as compared with those coated with PLGA group, and had significantly higher endothelial scores than both PEVA/PBMA and PLGA groups (PLGA/ACP vs. PLGA, restenosis%: 21.24 ± 2.59 vs. 32.12 ± 3.93, P < 0.05; inflammatory score: 1.25 ± 0.35 vs. 2.30 ± 0.21, P < 0.05. PLGA/ACP vs. PEVA/PBMA vs. PLGA, endothelial scores: 1.78 ± 0.46 vs. 1.17 ± 0.18 vs. 1.20 ± 0.18, P < 0.05). Inflammatory cell infiltration in the target vessel walls (Rabbit Iliac Arteries) were significantly less in PLLA/ACP group than that in PLLA group (PLLA/ACP vs. PLLA, % NF-κB-positive cells: 12.23 ± 1.36% vs. 24.13 ± 1.45%, P < 0.05). At three months, PLGA/ACP group had no necrotic neointima and higher endothelial scores compared with PEVA/PBMA group (PLGA/ACP vs. PEVA/PBMA, inflammatory score: 1.33 ± 0.33 vs. 2.27 ± 0.55, P < 0.05; endothelial score: 2.33 ± 0.33 vs. 1.20 ± 0.18, P < 0.05). Systemically, no biochemical and pathological evidence of toxicity were found in both rat and rabbit species after one and three month implantation for both PLGA/ACP and PLLA/ACP composites.

Conclusions PLLA/ACP and PLGA/ACP may potentially be promising biodegradable materials in making biodegradable drug eluting stent either as a coating or stent platform.

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