Orthopaedic Sports Medicine and Knee Surgery, Dept. of Orthopaedic Surgery and Traumatology, Inselspital University of Bern, 3010 Bern, Switzerland.
Curr Pharm Biotechnol. 2012 Jun;13(7):1196-206. doi: 10.2174/138920112800624337.
Surgical repair of the rotator cuff repair is one of the most common procedures in orthopedic surgery. Despite it being the focus of much research, the physiological tendon-bone insertion is not recreated following repair and there is an anatomic non-healing rate of up to 94%. During the healing phase, several growth factors are upregulated that induce cellular proliferation and matrix deposition. Subsequently, this provisional matrix is replaced by the definitive matrix. Leukocyte- and platelet-rich fibrin (L-PRF) contain growth factors and has a stable dense fibrin matrix. Therefore, use of LPRF in rotator cuff repair is theoretically attractive. The aim of the present study was to determine 1) the optimal protocol to achieve the highest leukocyte content; 2) whether L-PRF releases growth factors in a sustained manner over 28 days; 3) whether standard/gelatinous or dry/compressed matrix preparation methods result in higher growth factor concentrations. 1) The standard L-PRF centrifugation protocol with 400 x g showed the highest concentration of platelets and leukocytes. 2) The L-PRF clots cultured in medium showed a continuous slow release with an increase in the absolute release of growth factors TGF-β1, VEGF and MPO in the first 7 days, and for IGF1, PDGF-AB and platelet activity (PF4=CXCL4) in the first 8 hours, followed by a decrease to close to zero at 28 days. Significantly higher levels of growth factor were expressed relative to the control values of normal blood at each culture time point. 3) Except for MPO and the TGFβ-1, there was always a tendency towards higher release of growth factors (i.e., CXCL4, IGF-1, PDGF-AB, and VEGF) in the standard/gelatinous- compared to the dry/compressed group. L-PRF in its optimal standard/gelatinous-type matrix can store and deliver locally specific healing growth factors for up to 28 days and may be a useful adjunct in rotator cuff repair.
肩袖修复术是矫形外科最常见的手术之一。尽管它是许多研究的焦点，但修复后无法重建生理上的肌腱-骨插入，解剖学上的非愈合率高达 94%。在愈合阶段，几种生长因子被上调，诱导细胞增殖和基质沉积。随后，这个临时基质被最终基质所取代。富含白细胞和血小板的纤维蛋白（L-PRF）含有生长因子，并且具有稳定的致密纤维蛋白基质。因此，LPRF 在肩袖修复中具有理论上的吸引力。本研究的目的是确定：1）获得最高白细胞含量的最佳方案；2）L-PRF 是否在 28 天内持续释放生长因子；3）标准/凝胶状或干燥/压缩基质制备方法是否导致更高的生长因子浓度。1）采用 400×g 的标准 L-PRF 离心方案可获得最高浓度的血小板和白细胞。2）在培养基中培养的 L-PRF 凝块显示出持续缓慢释放，在前 7 天内 TGF-β1、VEGF 和 MPO 的绝对释放增加，在前 8 小时内 IGF1、PDGF-AB 和血小板活性（PF4=CXCL4）增加，然后在 28 天时接近零。与每个培养时间点的正常血液对照值相比，生长因子的表达水平显著更高。3）除了 MPO 和 TGFβ-1 之外，在标准/凝胶状组中，生长因子（即 CXCL4、IGF-1、PDGF-AB 和 VEGF）的释放总是有更高的趋势。在最佳的标准/凝胶状基质中，L-PRF 可以储存和局部输送特定的愈合生长因子长达 28 天，可能是肩袖修复的有用辅助手段。
