Department of Periodontics, Dental School, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA.
J Periodontol. 2010 May;81(5):737-47. doi: 10.1902/jop.2010.090562.
A polyethylene glycol (PEG)-based hydrogel matrix covalently bound to a 35-amino acid peptide of parathyroid hormone cystein-PTH 1-34 (cys-PTH 1-34) was shown to enhance bone regeneration around implants. The aim of this study is to test if the addition of an integrin-receptor-binding arginine-glycine-aspartic acid (RGD)-containing peptide at early healing time points improves the performance of the PEG matrix supplemented with cys-PTH 1-34 (PTH) when applied in acute defects around implants at early healing time points (2 and 4 weeks).
Six dogs received 48 implants. Each side of the mandible was randomly assigned for implantation at day 0 or 2 weeks. A circumferential critical-size defect was created at each site before implantation. Sites were randomly assigned to one of four groups: 1) PEG alone (PEG group), 2) PEG plus RGD (PEG/RGD group), 3) PEG plus PTH (PEG/PTH group), and 4) PEG plus RGD plus PTH (PEG/RGD/PTH group). Dogs were sacrificed 2 weeks after the second surgery, and specimens were obtained for histologic analysis. For the statistical analysis, mixed linear regression with repeated measurements was used, and a Dunnett-Hsu adjustment was made for multiple comparisons.
At 2 weeks, the percentages of new bone formation within the defect were 12.43% for the PEG group, 15.95% for the PEG/RGD group, 15.32% for the PEG/PTH group, and 16.60% for the PEG/RGD/PTH group. At 4 weeks, the percentages of new bone formation within the defect were 30.01% for the PEG group, 27.90% for the PEG/RGD group, 29.89% for the PEG/PTH group, and 27.58% for the PEG/RGD/PTH group. A marginally significant difference (PEG/RGD/PTH group versus PEG group; P = 0.055) was found at 2 weeks but not at 4 weeks. The highest percentage of bone-to-implant contact (BIC) in the defect site at 2 weeks was observed for the PEG/RGD group (8.57%). The BIC after 4 weeks of healing ranged from 11.54% (PEG/RGD/PTH group) to 16.61% (PEG group). No statistically significant differences were observed in BIC.
The effect of binding PTH covalently to a synthetic, RGD-modified PEG hydrogel marginally significantly improved bone formation at 2 weeks of healing compared to the use of PEG alone. Bone regeneration within the defects increased in all groups at week 4 of healing without statistically significant differences.
一种聚乙二醇（PEG）基水凝胶基质与甲状旁腺激素半胱氨酸-PTH 1-34（cys-PTH 1-34）的 35 个氨基酸肽共价结合，被证明能增强植入物周围的骨再生。本研究的目的是测试在植入物周围的急性缺损早期愈合时间点（2 周和 4 周），添加整合素受体结合的精氨酸-甘氨酸-天冬氨酸（RGD）肽是否会提高补充有 cys-PTH 1-34（PTH）的 PEG 基质的性能。
六只狗接受了 48 个植入物。下颌骨的每一侧都随机分配在第 0 天或第 2 周植入。在每个部位植入前创建一个环绕的临界尺寸缺陷。这些部位随机分为四组之一：1）PEG 单独（PEG 组），2）PEG 加 RGD（PEG/RGD 组），3）PEG 加 PTH（PEG/PTH 组）和 4）PEG 加 RGD 加 PTH（PEG/RGD/PTH 组）。在第二次手术后 2 周，对狗进行了安乐死，并获得标本进行组织学分析。对于统计分析，使用具有重复测量的混合线性回归，并对多重比较进行了 Dunnett-Hsu 调整。
在 2 周时，PEG 组、PEG/RGD 组、PEG/PTH 组和 PEG/RGD/PTH 组缺陷内新骨形成的百分比分别为 12.43%、15.95%、15.32%和 16.60%。在 4 周时，PEG 组、PEG/RGD 组、PEG/PTH 组和 PEG/RGD/PTH 组缺陷内新骨形成的百分比分别为 30.01%、27.90%、29.89%和 27.58%。在 2 周时发现一个边缘显著差异（PEG/RGD/PTH 组与 PEG 组；P = 0.055），但在 4 周时没有发现差异。在 2 周时，缺陷部位的骨-植入物接触（BIC）百分比最高的是 PEG/RGD 组（8.57%）。愈合 4 周后，BIC 范围从 11.54%（PEG/RGD/PTH 组）到 16.61%（PEG 组）。BIC 无统计学差异。
与单独使用 PEG 相比，将 PTH 共价结合到合成的、RGD 修饰的 PEG 水凝胶上，在 2 周的愈合期，对骨形成的影响略有改善。所有组在第 4 周愈合时，缺陷内的骨再生均增加，无统计学差异。
