Science Trans Med：水凝胶促进膝关节软骨修复

约翰·霍普金斯大学的Blanka Sharma博士及其同事在1月9 日的《科学转化医学》(Science Translational Medicine)上报告的一项小型初步试验显示，一种光固化水凝胶结合微骨折术的治疗方式可促进膝关节的软骨修复。

当应用于膝关节清创缺损时，凝胶渗入软骨下微细裂隙，聚集微细裂隙释放的血液，并形成血凝块，填补大部分的骨缺损。与完全由微骨折术形成的血凝块相比，凝胶血凝块的体积更大，提示“可能在缺损部位容留更多的蛋白和细胞......进一步强化可以促进新组织生长的生物因素"。

作者对于15例有2~4 cm²症状性股骨内侧髁软骨缺损的患者采用光聚合凝胶结合微骨折术治疗，3例有相似缺损的患者接受标准的微骨折手术。这项研究比较了两组术后6个月期间的愈合、功能和疼痛状况(Sci. Trans. Med. 2013;5:167ra6)。术后3个月，研究组MRI扫描显示缺损处形成血块物质、水凝胶和滑液组成的一种复合物。6个月时，研究组缺损处平均有86%的新组织填充，微细裂隙手术组仅有平均64%缺损被填充，具有统计学差异。研究组多数患者（14例中的12例）MRI评估的缺损填充超过75%，而3例对照患者中仅有1例MRI评估的缺损填充超过75%。

多数患者接受水凝胶治疗的患者还伴有显著的疼痛频率和严重程度降低，最明显的改善发生于术后最初的3个月。这一组有1例患者在6个月时仍有疼痛。在术后最初3个月，对照组患者发生相似的疼痛频率和严重程度显著降低。

6个月时，对照组有1例患者仍有持续的疼痛改善，这例患者的缺损填充数值也较高（84%），而另外2例患者的填充数值均低于75%，作者指出。6个月时，两组疼痛频率评分无显著差异。疼痛严重程度评分也相似。并且，两组的膝关节功能也得到相似的改善。

研究者总结认为，与微骨折手术相比，水凝胶治疗可促进膝关节的软骨修复。

这项研究是由美国国立卫生研究院和关节炎基金会资助的。作者披露无相关利益冲突。

Human Cartilage Repair with a Photoreactive Adhesive-Hydrogel Composite

ABSTRACT

Surgical options for cartilage resurfacing may be significantly improved by advances and application of biomaterials that direct tissue repair. A poly(ethylene glycol) diacrylate (PEGDA) hydrogel was designed to support cartilage matrix production, with easy surgical application. A model in vitro system demonstrated deposition of cartilage-specific extracellular matrix in the hydrogel biomaterial and stimulation of adjacent cartilage tissue development by mesenchymal stem cells. For translation to the joint environment, a chondroitin sulfate adhesive was applied to covalently bond and adhere the hydrogel to cartilage and bone tissue in articular defects. After preclinical testing in a caprine model, a pilot clinical study was initiated where the biomaterials system was combined with standard microfracture surgery in 15 patients with focal cartilage defects on the medial femoral condyle. Control patients were treated with microfracture alone. Magnetic resonance imaging showed that treated patients achieved significantly higher levels of tissue fill compared to controls. Magnetic resonance spin-spin relaxation times (T2) showed decreasing water content and increased tissue organization over time. Treated patients had less pain compared with controls, whereas knee function [International Knee Documentation Committee (IKDC)] scores increased to similar levels between the groups over the 6 months evaluated. No major adverse events were observed over the study period. With further clinical testing, this practical biomaterials strategy has the potential to improve the treatment of articular cartilage defects.