Platelet-leukocyte gel (PLG) contains high concentrations of platelets and leukocytes. As leukocytes play an important role in the innate host-defense, we hypothesized that PLG might have antimicrobial properties. This study investigated the antimicrobial activity of PLG against Staphylococcus aureus and the contribution of myeloperoxidase (MPO), present in leukocytes, in this process. Platelet-rich plasma (PRP) and platelet-poor plasma (PPP) were obtained from whole blood of six donors. PLG was prepared by mixing PRP with autologous (PLG-AT) or bovine thrombin (PLG-BT). Antimicrobial activity of PLG-AT, PLG-BT, PRP, and PPP was determined in a bacterial kill assay. MPO release was measured by ELISA and activity was measured using a MPO activity assay. Cultures showed a rapid decrease in the number of bacteria for both PLG-AT and PLG-BT, which was maximal between 4 and 8 h, to approximately 1% of the bacteria in controls. The effect of PLG-AT was largest and significantly different compared to PRP ( p ¼ 0.004) and PPP ( p < 0.001), however not compared to PLG-BT ( p ¼ 0.093). PLG-AT, PLG-BT, and PRP showed a comparable, gradually increasing MPO release. MPO activity was comparable for all groups and remained stable. No correlation between MPO release, activity, and bacterial kill could be found. PLG appears to have potent antimicrobial capacity, but the role of MPO in this activity is questionable. PLG might represent a useful strategy against postoperative infections. However, additional research should elucidate its exact antimicrobial activity. ß

Background: The therapeutic use of autologously prepared, platelet-leukocyte-enriched gel (PLG) is a relatively new technology for the stimulation and acceleration of soft tissue and bone healing. The effectiveness of this procedure lies in the delivery of a wide range of platelet growth factors mimicking the physiologic wound healing and reparative tissue processes. Despite an increase in PLG applications, the structures and kinetics of this autogenously derived biologic material have not been observed. Methods: A review of the most recent literature was performed to evaluate the use of PLG in various surgical disciplines. Results: The review showed that the application of PLG has been extended to various surgical disciplines including orthopedics, cardiac surgery, plastic and maxillofacial surgery, and recently also endoscopic surgery. Conclusion: This review demonstrates the usefulness of PLG in a wide range of clinical applications for improvement of healing after surgical procedures.Key words: Growth factors -Leukocytes -Platelet gel -Wound healing Soft tissue wound healing and bone growth involve physiologic cascades in which cellular and hormonal factors play pivotal roles [1,2]. Some of these cascade components can be isolated from autologously drawn whole blood. Point-of-care devices can intraoperatively fractionate the autologous blood into platelet-poor plasma, platelet-leukocyte-rich plasma (P-LRP), and red blood cells [3,4]. The P-LRP fraction, a mixture of concentrated platelets and leukocytes, can be activated by (autologous) thrombin to create a viscous solution known as platelet-leukocyte gel (PLG). This platelet coagulum can be exogenously applied to soft wound tissues, bone, or synthetic bone as a spray or as a solid, clotted, gelatinous mass. The rationale for applying platelet gel is based on the delivery of platelet growth factors to tissues and on the fact that platelet a-granules, found inside the platelets, contain a variety of growth factors [5]. Platelet gel growth factors are peptides that promote cell proliferation, differentiation, chemotaxis, and the migration of various cells involved in both wound healing and bone growth [6,7].Recently, numerous P-LRP devices have become available for therapeutic use to stimulate and accelerate soft tissue and bone healing and to control postoperative wound bleeding. The rationale for applying PLG lies in the mimicking and accelerating of physiologic wound healing and reparative tissue processes.This article provides information on the results of electron microscopic imaging used to evaluate the content of PLG. Furthermore, because the use of PLG is a relatively new per-and/or perioperative biotechnological application, new and additional indications for the use of PLG are defined. New PLG applications are reviewed for different applications including cardiac surgery, general surgery, orthopedics and traumatology, cosmetic surgery, maxillofacial surgery, sports medicine, and endoscopic surgical procedures. Defining platelet-leukocyte-rich...

Introduction:Postoperative delirium is the most common neurological complication of cardiac surgery. Hypoxia has been shown to increase the risk of postoperative delirium. The possibility to continuously monitor oxygen delivery (DO2) during cardiopulmonary bypass (CPB) offers an adequate approximation of the oxygen status in a patient. This study investigates the role of oxygen delivery during cardiopulmonary bypass in the incidence of postoperative delirium.Methods:Three hundred and fifty-seven adult patients who underwent normothermic coronary artery bypass grafting (CABG) surgery were included in this retrospective study. The nadir indexed DO2 (DO2i) value on bypass, the total time under the critical DO2i level and the area under the curve (AUC) for critical DO2i were determined. Delirium was identified by the postoperative administration of haloperidol.Results:The mean nadir DO2i significantly differed, comparing the group of patients with postoperative delirium to the group without. Multivariate analysis only identified age, pre-existing cognitive impairment, preoperative kidney dysfunction and cross-clamp time as independent risk factors for delirium. The results also indicated that patients of older age were more sensitive to a declined DO2i.Conclusion:A low DO2i during cardiopulmonary bypass is significantly associated with the incidence of postoperative delirium in CABG patients. However, the role of DO2 as an independent predictor of delirium could not be proven.

Background: Chronic pain is the main complication following inguinal hernia repair. A possible explanatory factor is the suture fixation of the mesh. Glue fixation might overcome this problem. Albeit at a very low frequency, human and bovine components of fibrin sealants currently available could contain blood-borne pathogens. Autologous platelet-rich fibrin sealant (P-RFS) eliminates this risk and has additional advantages such as hemostatic and antibacterial effects. Therefore, its feasibility was assessed in inguinal hernia repair, with a focus on pain. Methods: In 22 patients with primary inguinal hernia, the mesh was fixated with P-RFS. Data included operative variables, complications, pain scores and neurological examinations. Long-term follow-up was 22.2 months (SD 2.2) postoperatively. Results: After 2 weeks, visual analogue scale and disability pain scores were lower than they were preoperatively. Complications at 3 months were 1 recurrence, 1 chronic pain and 6 sensory disturbances. At the last clinical evaluation, the recurrence was planned for repair due to discomfort. No chronic pain, sensory disorders or discomfort was reported at long-term follow-up. Conclusion: Mesh fixation with autologous P-RFS is feasible. If there is a preference for autologous material, P-RFS is indicated. If glue fixation becomes standard, further randomized studies are warranted for this alternative.

Background/Objectives: The increasing complexity of patients undergoing cardiac surgery requires extended myocardial ischaemic periods. Cardiac surgeons demand a cardioplegic solution with prolonged myocardial protection. Therefore, we introduced Custodiol in our centre in 2011. The aim of this study was to investigate the safety and efficacy of Custodiol compared with the standard method of cardioplegia. Methods: Between 2011 and 2016, 188 adult patients who underwent mitral valve surgery combined with coronary artery bypass grafting were included in this retrospective study. In 113 patients, Custodiol cardioplegia was used to achieve cardiac arrest, while St. Thomas Hospital solution was used in 75 patients. The primary endpoint of the study was the degree myocardial damage which was estimated by the measurement of creatine kinase-myocardial band on the first postoperative day. A linear regression analysis was performed to compare the aortic cross-clamp time with the postoperative myocardial damage in both groups. Results: The extracorporeal circulation time and aortic cross-clamp were significantly longer in the Custodiol group than in the St. Thomas group: 125.6 ± 32.5 minutes versus 93.1 ± 27.7 minutes (p < 0.001), respectively. However, there was no significant difference between the two groups regarding the postoperative levels of creatine kinase-myocardial band (96 (70-140) U/L vs. 86 (69-120) U/L, respectively; p = 0.321). There was no significant differences between the two groups regarding the 30-day mortality (6.1% vs. 5.5%, respectively; p = 1.000) or 120-day mortality (9.6% vs. 11.0%, respectively; p = 0.806). Conclusion: Our findings demonstrate that Custodiol is a safe method of myocardial protection for patients who underwent mitral valve surgery with coronary artery bypass grafting in our hospital. Further investigations extended to more cardiac surgery populations are needed to confirm clinical benefits of Custodiol cardioplegia.