Clinical application of platelet-rich plasma (PRP) and stem cells has become more and more important in regenerative medicine during the last decade. However, differences in PRP preparations may contribute to variable PRP compositions with unpredictable effects on a cellular level. In the present study, we modified the centrifugation settings in order to provide a leukocyte-reduced PRP and evaluated the interactions between PRP and adipose-tissue derived mesenchymal stem cells (ASCs).PRP was obtained after modification of three different centrifugation settings and investigated by hemogram analysis, quantification of protein content and growth factor concentration. ASCs were cultured in serum-free α-MEM supplemented with autologous 10% or 20% leukocyte-reduced PRP. Cell cycle kinetics of ASCs were analyzed using flow cytometric analyses after 48 hours.Thrombocytes in PRP were concentrated, whereas erythrocytes, and white blood cells (WBC) were reduced, independent of centrifugation settings. Disabling the brake further reduced the number of WBCs. A higher percentage of cells in the S-phase in the presence of 20% PRP in comparison to 10% PRP and 20% fetal calf serum (FCS) advocates the proliferation stimulation of ASCs.These findings clearly demonstrate considerable differences between three PRP separation settings and assist in safeguarding the combination of leukocyte-reduced PRP and stem cells for regenerative therapies.

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Depending on the specific injury profile of each team sports, injury prevention strategies should address competitive as well as training situations, whichmay need different strategies.

The historical treatment options for partial anterior cruciate ligament (ACL) ruptures were conservative therapy or ACL reconstruction by injured bundle or entire ACL replacement. In awareness of the regenerative potential of biologic agents such as mesenchymal stem cells or platelet rich plasma (PRP), the healing response technique was developed to preserve the injured ACL with better outcomes than the conservative therapy. Further improvement of this technique seems to be obtained by the additional application of PRP products. Thus, the aim of this study was to evaluate the midterm outcome after intraligament autologous conditioned plasma (ACP) by a clinical, scoring, and functional performance assessment. 42 patients were evaluated in this study. The failure rate was 9.5%. Outcome evaluation showed good to excellent results. The scores were IKDC subjective 83.2 (SD 14.5), Lysholm 85.5 (SD 15.5), Tegner 4.7 (SD 1.7), and Cincinnati 85.4 (SD 15.5) after a mean follow-up of 33 months. Clinical examination showed stable Lachman test, negative pivot shift phenomenon, and a significant reduction in AP-laxity compared to preoperative status (rolimeter preoperative: 1.9 (SD1.4); postoperative 0.6 (SD1.8), p=0.001) in all patients. Functional performance testing showed no significant differences between the injured and healthy side. Return to sport was achieved after a mean of 5.8 months (SD 3.6) in 71.1% of the included patients. In summary, this new treatment option revealed in midterm follow-up promising results to treat partial ACL lesions with a reduced need for conversion to ACL reconstruction and with a high percentage of return to preinjury sport activity.

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