Objectives. This study was conducted to evaluate the cytokine-release kinetics of platelet-rich plasma (PRP) according to different activation protocols. Methods. Two manual preparation procedures (single-spin (SS) at 900 g for five minutes; double-spin (DS) at 900 g for five minutes and then 1500 g for 15 minutes) were performed for each of 14 healthy subjects. Both preparations were tested for platelet activation by one of three activation protocols: no activation, activation with calcium (Ca) only, or calcium with a low dose (50 IU per 1 ml PRP) of thrombin. Each preparation was divided into four aliquots and incubated for one hour, 24 hours, 72 hours, and seven days. The cytokine-release kinetics were evaluated by assessing PDGF, TGF, VEGF, FGF, IL-1, and MMP-9 concentrations with bead-based sandwich immunoassay. Results. The concentration of cytokine released from PRP varied over time and was influenced by various activation protocols. Ca-only activation had a significant effect on the DS PRPs (where the VEGF, FGF, and IL-1 concentrations were sustained) while Ca/thrombin activation had effects on both SS and DS PRPs (where the PDGF and VEGF concentrations were sustained and the TGF and FGF concentrations were short). The IL-1 content showed a significant increase with Ca-only or Ca/thrombin activation while these activations did not increase the MMP-9 concentration. Conclusion. The SS and DS methods differed in their effect on cytokine release, and this effect varied among the cytokines analysed. In addition, low dose of thrombin/calcium activation increased the overall cytokine release of the PRP preparations over seven days, relative to that with a calcium-only supplement or non-activation. Cite this article: Professor J. H. Oh. Cytokine-release kinetics of platelet-rich plasma according to various activation protocols. Bone Joint Res 2016;5:37–45. doi: 10.1302/2046-3758.52.2000540

Thrombin has many biological properties similar to those of growth factors. In a previous study, we showed that thrombin improves healing of the rat tendo Achillis. Low molecular weight heparin (LMWH) inhibits the activity and the generation of thrombin. We therefore considered that LMWH at a thromboprophylactic dose might inhibit tendon repair. Transection of the tendo Achillis was carried out in 86 rats and the healing tested mechanically. Low molecular weight heparin (dalateparin) was either injected a few minutes before the operation and then given continuously with an osmotic mini pump for seven days, or given as one injection before the operation. In another experiment ,we gave LMWH or a placebo by injection twice daily. The anti-factor Xa activity was analysed. Continuous treatment with LMWH impaired tendon healing. After seven days, this treatment caused a 33% reduction in force at failure, a 20% reduction in stiffness and a 67% reduction in energy uptake. However, if injected twice daily, LMWH had no effect on tendon healing. Anti-factor Xa activity was increased by LMWH treatment, but was normal between intermittent injections. Low molecular weight heparin delays tendon repair if given continuously, but not if injected intermittently, probably because the anti-factor Xa activity between injections returns to normal, allowing sufficient thrombin stimulation for repair. These findings indicate the need for caution in the assessment of long-acting thrombin and factor Xa inhibitors

Abstract. Objectives. Bone marrow aspirate concentrate (BMAC), together with fibrin glue (Tisseel, Baxter, UK) and Hyaluronic acid (HA) were used as a one-step cell therapy treating patients with ankle cartilage defects in our hospital. This therapy was proven to be safe, with patients demonstrating a significant improvement 12 months post-treatment. Enriched mesenchymal stem cells (MSCs) in BMAC are suggested inducers of cartilage regeneration, however, currently there is no point-of-care assessment for BMAC quality; especially regarding the proportion of MSCs within. This study aims to characterise the cellular component of CCR-generated BMAC using a point-of-care device, and to investigate if the total nucleated cell (TNC) count and patient age are predictive of MSC concentration. Methods. During surgery, 35ml of bone marrow aspirate (BMA) was collected from each patients’ iliac crest under anaesthesia, and BMAC was obtained via a commercial kit (Cartilage Regeneration kit, CCR, Innotec. ®. , UK). BMAC was then mixed with thrombin (B+T) for injection with HA and fibrinogen. In our study, donor-matched BMA, BMAC and B+T were obtained from consented patients (n=12, age 41 ± 16years) undergoing surgery with BMAC therapy. TNC, red blood cell (RBC) and platelet (PLT) counts were measured via a haematology analyser (ABX Micros ES 60, Horiba, UK), and the proportion of MSCs in BMA, BMAC and B+T were assessed via colony forming unit-fibroblast (CFU-F) assays. Significant differences data in matched donors were tested using Friedman test. All data were shown as mean ± SD. Results. Mean TNC counts in BMA and BMAC were not significantly different (14.0 ± 4.4 million/ml and 19.4 ± 32.9 million/ml, respectively, P>0.9999). However, TNC counts were significantly lower in B+T compared to BMAC (9.7 ± 24.5 million/ml and 19.4 ± 32.9 million/ml, respectively, P=0.0167). Similarly, PLT counts were decreased in B+T compared to BMAC (40.7 ± 30.7 million/ml and 417.5 ± 365.5 million/ml, respectively, P<0.0001), however, PLTs were significantly concentrated in BMAC compared to BMA (417.5 ± 365.5 million/ml and 114.8 ± 61.6 million/ml, respectively, P=0.0429). RBC counts were significantly decreased in BMAC and B+T compared to BMA (P=0.0322 and P<0.0001, respectively). Higher concentration of MSCs were observed in BMAC compared to BMA (0.006% ± 0.01% and 0.00007% ± 0.0001%, respectively, P=0.0176). Similar to TNCs and PLTs, the proportion of MSCs significantly decreased in B+T compared to BMAC (0.0004% ± 0.001% and 0.006% ± 0.01%, respectively, P=0.0023). Furthermore, patient age and TNC counts did not correlate with MSC concentration (Spearman's Rank test, P=0.3266 and P=0.4880, respectively). Conclusions. BMAC successfully concentrated PLTs, but BMAC preparations were highly variable. Mixing BMAC and thrombin however, as described in the CCR protocol, resulted in a dramatic reduction in TNCs, PLTs and MSCs. TNC counts and patient age could not be used to predict the MSC proportion in the BMAC based on current data. Future work aims to look at the biomolecule profile of BMAC plasma, and to correlate them to patient clinical outcomes. Declaration of Interest. (a) fully declare any financial or other potential conflict of interest

Our previous rat study demonstrated an ex vivo-created “Biomimetic Hematoma” (BH) that mimics the intrinsic structural properties of normal fracture hematoma, consistently and efficiently enhanced the healing of large bone defects at extremely low doses of rhBMP-2 (0.33 μg). The aim of this study was to determine if an extremely low dose of rhBMP-2 delivered within BH can efficiently heal large bone defects in goats. Goat 2.5 cm tibial defects were stabilized with circular fixators, and divided into groups (n=2-3): 2.1 mg rhBMP-2 delivered on an absorbable collagen sponge (ACS); 52.5 μg rhBMP-2 delivered within BH; and an empty group. BH was created using autologous blood with a mixture of calcium and thrombin at specific concentrations. Healing was monitored with X-rays. After 8 weeks, femurs were assessed using microCT. Using 2.1 mg on ACS was sufficient to heal 2.5 cm bone defects. Empty defects resulted in a nonunion after 8 weeks. Radiographic evaluation showed earlier and more robust callus formation with 97.5 % (52.5 μg) less of rhBMP-2 delivered within the BH, and all tibias were fully bridged at 3 weeks. The bone mineral density was significantly higher in defects treated with BH than with ACS. Defects in the BH group had smaller amounts of intramedullary and cortical trabeculation compared to the ACS group, indicating advanced remodeling. The results confirm that the delivery of rhBMP-2 within the BH was much more efficient than on an ACS. Not only did the large bone defects heal consistently with a 40x lower dose of rhBMP-2, but the quality of the defect regeneration was also superior in the BH group. These findings should significantly influence how rhBMP-2 is delivered clinically to maximize the regenerative capacity of bone healing while minimizing the dose required, thereby reducing the risk of adverse effects

Currently, fibrin glue obtained from fibrinogen and thrombin of human and animal blood are widely investigated to use as injectable hydrogel for tissue engineering which contributes to minimally invasive surgery, superior biodegradability, cell attachment, proliferation and regenerating new tissue. However, most of them fail to achieve to be used for tissue engineering application because of a risk of immune response and poor mechanical properties. To overcome the limitation of fibrin glue and to reduce the usage of products from human and animal blood, the artificial fibrin glue materials were developed. Recently, cellulose nanofiber (CNF) as reinforcing agent has been explored for many tissue engineering applications such as bone and cartilage due to its impressive biological compatibility, biodegradability and mechanical properties. CNF was extracted from cassava pulp. PEO-PPO-PEO diacrylate block copolymer is a biodegradable synthetic polymers which is water insoluble hydrogel after curing by UV light at low intensity. To enhance the cell adhesion abilities, gelatin methacrylate (GelMA), the denature form of collagen was used to incorporate into hydrogel. The aim of this study was to develop the artificial fibrin glue from CNF reinforced PEO-PPO-PEO diacrylate block copolymer/GelMA injectable hydrogel. CNF/PEO-PPO-PEO diacrylate block copolymer/GelMA injectable hydrogels were prepared with 2-hydroxy-1-(4-(hydroxy ethoxy) phenyl)-2-methyl-1-propanone (Irgacure 2959) as a photoinitiator. The physicochemical properties were investigated by measuring various properties such as thickness, gel fraction, mechanical properties and water uptake. At optimal preparation condition, CNF reinforced injectable hydrogel was successful prepared after curing with UV light within 7 minutes. This hydrogel showed gel fraction and water uptake of 81 and 85%, respectively. The cytotoxicity, cell adhesion and proliferation of CNF reinforced injectable hydrogel was presented. Cellulose nanofiber from casava pulp was successfully used to prepare injectable hydrogel as artificial fibrin glue for tissue engineering. The hydrogel showed good physical properties which can be applied to use for tissue engineering application

Tendon injuries constitute a major healthcare burden owing to the limited healing ability of these tissues and the poor clinical outcomes of surgical repair treatments. Recent advances in tendon tissue engineering (TTE) strategies, particularly through the use of biotextile technologies, hold great promise toward the generation of artificial living tendon constructs. We have previously developed a braided construct based on suture threads coated with gelMA:alginate hydrogel encapsulating human tendon cells. These cell-laden composite fibers enabled the replication of cell and tissue-level properties simultaneously. Based on this concept, in this study we explored the use of platelet lysate (PL), a pool of supra-physiological concentrations of growth factors (GFs), to generate a hydrogel layer, which is envisioned to act as a depot of therapeutic factors to induce tenogenic differentiation of encapsulated human adipose stem cells (hASCs). For this purpose, commercially available suture threads were first embedded in a thrombin solution and then incubated in PL containing hASCs. Herein, thrombin induces the gelation of PL and consequent hydrogel formation. After coating suture threads with the mixture of PL-ASCs, cells were found to be viable and homogeneously distributed along the fibers. Strikingly, hASCs encapsulated within the PL hydrogel layer around the suture thread were able to sense chemotactic factors present in PL and to establish connections between adjacent independent fibers, suggesting a tremendous potential of PL cell-laden hydrogel fibers as building blocks in the development of living constructs aimed at tendon repair applications

Platelet-rich plasma is a new inductive therapy which is being increasingly used for the treatment of the complications of bone healing, such as infection and nonunion. The activator for platelet-rich plasma is a mixture of thrombin and calcium chloride which produces a platelet-rich gel. We analysed the antibacterial effect of platelet-rich gel in vitro by using the platelet-rich plasma samples of 20 volunteers. In vitro laboratory susceptibility to platelet-rich gel was determined by the Kirby-Bauer disc-diffusion method. Baseline antimicrobial activity was assessed by measuring the zones of inhibition on agar plates coated with selected bacterial strains. Zones of inhibition produced by platelet-rich gel ranged between 6 mm and 24 mm (mean 9.83 mm) in diameter. Platelet-rich gel inhibited the growth of Staphylococcus aureus and was also active against Escherichia coli. There was no activity against Klebsiella pneumoniae, Enterococcus faecalis, and Pseudomonas aeruginosa. Moreover, platelet-rich gel seemed to induce the in vitro growth of Ps. aeruginosa, suggesting that it may cause an exacerbation of infections with this organism. We believe that a combination of the inductive and antimicrobial properties of platelet-rich gel can improve the treatment of infected delayed healing and nonunion

Summary Statement. An autologous thrombin activated 3-fold PRP, mixed with a biphasic calcium phosphate at a 1mL:1cc ratio, is beneficial for early bone healing in older age sheep. Introduction. The management of bone defects continues to present challenges. Upon activation, platelets secrete an array of growth factors that contribute to bone regeneration. Therefore, combining platelet rich plasma (PRP) with bone graft substitutes has the potential to reduce or replace the reliance on autograft. The simple, autologous nature of PRP has encouraged its use. However, this enthusiasm has failed to consistently translate to clinical expediency. Lack of standardisation and improper use may contribute to the conflicting outcomes reported within both pre-clinical and clinical investigations. This study investigates the potential of PRP for bone augmentation in an older age sheep model. Specifically, PRP dose is controlled to provide clearer indications for its clinical use. Methods. Eighty 11mm diameter defects of 20mm in depth were created in the cancellous bone within the epiphyseal region of the medial proximal tibia and distal femur of twenty five-year-old sheep. The defects were treated with three doses of an autologous thrombin activated PRP combined with a biphasic calcium phosphate (BCP). Activated platelet poor plasma (PPP) and the BCP alone provided reference groups, while the autograft and empty defects served as controls. All animals were sacrificed at four weeks post-operatively for radiographic assessment, micro-computed tomography quantification, histological assessment, histomorphometric quantification of new bone area and bone ingrowth, and weekly fluorochrome bone label quantification. TGF-β1 concentrations were quantified using enzyme-linked immunosorbent assays. Results. The PRP had a 2.9-fold (0.4) increase in platelet concentration, a 0.57-fold (0.09) decrease in leukocytes, and a 0.65-fold (0.11) decrease in fibrinogen. After activation, the PRP had an 8.9-fold (1.5) increase in TGF-β1 serum concentration above baseline. Eleven (11) mm diameter cancellous bone defects in the hind legs of five-year-old sheep do not spontaneously heal within four weeks. PRP dose had a significant effect on the radiographic grade. The highest dose of PRP treatment had a significantly greater micro-CT BV/TV over the BCP alone (PRP: 30.6±1.8%; BCP: 24.5±0.1%). All doses of PRP treatment were significantly greater than the BCP alone for both the histomorphometric new bone area (PRP: 14.5±1.3%; BCP: 9.7±1.5%) and bone ingrowth depth (PRP: 2288±210µm; BCP:1151±268µm). From week two onwards, PRP had a significant effect on the weekly bone ingrowth over BCP, however, autograft had the greatest amount of fluorescently labelled bone within the first three weeks. PRP has a significant effect on the shape and density of osteoblasts within the central region of the defect compared to the BCP alone, however, was not significantly different to autograft. TGF-β1 appeared a better predictor of healing outcomes than platelet concentration, however both had relatively weak correlations (r<.324). Conclusion. PRP induces new bone formation with a dose dependant response at four weeks when used with a biphasic calcium phosphate in older age sheep

We developed a 3D vascularized bone remodeling model embedding human osteoblast and osteoclast precursors and endothelial cells in a mineralized matrix. All the cells included in the model exerted their function, resulting in a vascularized system undergoing mineralized matrix remodeling. Bone remodeling is a dynamic process relying on the balance between the activity of osteoblasts and osteoclasts which are responsible for bone formation and resorption, respectively. This process is also characterized by a tight coupling between osteogenesis and angiogenesis, indicating the existence of a complex cross-talk between endothelial cells and bone cells. We have recently developed microscale in vitro hydrogel-based models, namely the 3D MiniTissue models, to obtain bone-mimicking microenvironments including a 3D microvascular network formed by endothelial cell self-assembly [1–2]. Here, we generated a vascularized 3D MiniTissue bone remodeling model through the coculture of primary human cells in a 3D collagen/fibrin (Col/Fib) matrix enriched with CaP nanoparticles (CaPn) to mimic bone mineralized matrix. Human umbilical vein endothelial cells (HUVECs), bone marrow mesenchymal stem cells (BMSCs), osteoblast (OBs) and osteoclast (OCs) precursors were cocultured in plain and CaPn-enriched Col/Fib according to the following experimental conditions: a) HUVECs-BMSCs; b) OBs-OCs; c) HUVECs-BMSCs-OBs-OCs. Undifferentiated BMSCs were used to support HUVECs in microvascular network formation. BMSCs and peripheral blood mononuclear cells were respectively pre-differentiated into OB and OC precursors through 7 days of culture in osteogenic or osteoclastogenic medium. Needle-shaped CaPn (Ø ∼20 nm, length ∼80 nm) were added to a collagen/fibrinogen solution. Cells were resuspended in a thrombin solution and then mixed with plain or CaPn-enriched collagen/fibrinogen. The cell-laden mix was injected in U-shaped PMMA masks and let to polymerize to generate constructs of 2×2×5 mm. 3. Samples were cultured for 10 days. Microvascular network formation was evaluated by confocal microscopy. OB differentiation was analyzed by quantification of Alkaline Phosphatase (ALP) and cell-mediated mineralization. OC differentiation was assessed by Tartrate-Resistant Acid Phosphatase (TRAP) and cell-mediated phosphate release quantification. HUVECs developed a robust 3D microvascular network and BMSCs differentiated into mural cells supporting vasculogenesis. The presence of CaPn enhanced OB and OC differentiation, as demonstrated by the significantly higher ALP and TRAP levels and by the superior cell-mediated mineralization and phosphate release measured in CaPn-enriched than in plain Col/Fib. The coculture of OBs and OCs with HUVECs and BMSCs further enhanced ALP and TRAP levels, indicating that the presence of HUVECs and BMSCs positively contributed to OB and OC differentiation. Remarkably, higher values of ALP and TRAP activity were measured in the tetraculture in CaPn-enriched Col/Fib compared to plain Col/Fib, indicating that also in the tetraculture the mineralized matrix stimulated OB and OC differentiation. The 3D MiniTissue bone remodeling model developed in this study is a promising platform to investigate bone cell and endothelial cell cross-talk. This system allows to minimize the use of cells and reagents and is characterized by a superior ease of use compared to other microscale systems, such as microfluidic models. Finally, it represents a suitable platform to test drugs for bone diseases and can be easily personalized with patient-derived cells further increasing its relevance as drug screening platform

Low molecular weight heparin (LMWH) is frequently used as thromboprophylaxis after major orthopaedic surgery. Varying levels of non-adherence (5% to 45%) with outpatient LMWH has been reported. Oral direct thrombin inhibitors have been recommended by industry due to ease of administration. We aim to audit the compliance rate with outpatient LMWH treatment following primary total hip arthroplasties (THA) in our district general hospital (DGH). Using the ORMIS computer system, we identified all primary THA performed in Monklands Hospital between July 2011 and August 2012. Patients’ case notes were analysed retrospectively, looking at operating surgeon's postoperative thromboprophylaxis instructions. We then conducted a telephone interview on patients discharged with outpatient LMWH to assess compliance. There were 58 primary THAs performed during the audit period. 33 patients were discharged on outpatient LMWH, whilst 15 patients and 3 patients were discharged on aspirin and warfarin respectively. Seven patients were excluded as their discharge prescriptions were missing. We successfully contacted 20 of the 33 patients discharged with outpatient LMWH. All respondents showed 100% compliance to the full course of treatment. 50% of patients self-administered; 30% were administered by district nurses and 20% by family members. 35% of patients preferred an oral tablet alternative, for its perceived ease of administration. Bruising and skin irritation were the reported problems in some patients, but these did not affect compliance. Contrary to the previous published non-adherence rates, the compliance rate with outpatient LMWH after THA was high in our DGH. The patient counseling, and family/district nurse involvement in may have contributed to this. However, our numbers of patients are low but data collection continues

Summary Statement. We have shown that integrin mRNA expression is regulated by the application of mechanical load. This indicates that mechanical loading may modify cell sensitivity to perceive further load through increased interaction with the ECM. Introduction. Tendinopathies are a range of diseases characterised by pain and insidious degeneration. Although poorly understood, onset is often associated with physical activity. We have previously investigated the regulation by mechanical strain of metalloproteinase gene expression in human tenocyte in a 3D collagen matrix. Integrins are important in cellular interaction with the ECM and are reported to mediate mechanotransduction in various non-tendon tissues. We have reported that TGFbeta activation is a key player in the regulation of metalloproteinases in response to mechanical load, which may be mediated by integrins. This project aims to investigate the effect of cyclic loading and TGFbeta stimulation on integrin expression by human tenocytes, in collagen and fibrin matrices. Methods. Human tenocytes were seeded at 1.5×106 cells/ml into collagen (rat tail type I, 1mg/ml) or fibrin (fibrinogen 6mg/ml, Thrombin 0.2u/ml) gels and stretched using a sinusoidal waveform of 0–5% at 1Hz using the Flexcell FX4000T(trade mark) system. Cultures were treated with or without 1ng/ml TGFbeta1 and load for 0–48 hours. Taqman Low density Array was used to asses a range of integrin, including ITGA1-6, ITGA10 and ITGA11 as well as ITGB1-5 (n=3). Results. In collagen cultures all integrins assayed were detectable (Ct < 35). ITGB1 was increased 2 fold with 48 hours of cyclic strain (p=0.006). ITGA6 and ITGA10 were decreased 1.4 and 2 fold with TGFbeta treatment after 24 hours (p=0.019, p=0.006). ITGA3 and ITGB3 were significantly decreased 7.6 and 8.3 fold with TGFbeta treatment after 48 hours (p=0.012, p=0.023). ITGA5 and ITGB1 showed similar responses with strain and TGFbeta, i.e. an increased trend. However, the other integrins showed a dissimilar response to strain and TGFbeta. Here we compare these responses to those in fibrin under the same conditions. Discussion. We have shown that integrin mRNA expression is regulated by the application of mechanical load. This indicates that mechanical loading may modify cell sensitivity to perceive further load through increased interaction with the ECM. Any differences in the cellular response to load in collagen and fibrin cultures, indicates that cellular interaction with the ECM is an important factor in the detection of load. Due to the differential regulation of some of the integrins with strain and TGFbeta, it appears that TGFbeta may not be responsible for the regulation of all integrins with strain. However this remains unconfirmed and may be explained by a temporal difference. Further analysis of how integrins are regulated in response to mechanical load and how this expression is translated to the protein level is required

The reinfusion of perioperative cell salvage is one method employed to reduce exposure to donor blood. Data on the safety of this process, however, are scant. Notably, the effect of intraoperative, washed cell salvage reinfusion on prothrombotic markers has not been demonstrated. The risk of postoperative venous thromboembolism following major orthopaedic operations is not insignificant. The study objective was to assess the effect of cell salvage reinfusion on coagulation and platelet activation. Twenty-one patients undergoing elective primary hip operations were recruited. Nine patients received washed cell salvage intraoperatively, and were compared with 12 patients undergoing similar surgery that did not. Two patients in the cell salvage group also received postoperative, unwashed cell salvage. Blood samples were collected pre-operatively, immediately post-operatively, and one day post-operatively for assays of platelet activation markers, P-selectin expression and fibrinogen binding by flow cytometry in diluted whole blood; coagulation activation marker, thrombin-antithrombin complex (TAT); D-dimer by ELISA, thrombin generation by chromogenic assay, and full blood count. Samples of cell salvage material were also analysed for prothrombotic markers. There were no significant differences between the groups preoperatively. Postoperatively haemoglobin levels did not differ significantly between the cell salvage group and controls. Postoperative TAT and D-dimer were significantly higher in the cell salvage group compared with controls (p<0.05). One day postoperatively, there were significantly higher platelet P-selectin expression (p=0.006) and platelet fibrinogen binding (p=0.004) in the cell salvage group compared with controls. The white cell count (WCC) was also significantly higher (p=0.04). In the intraoperative washed cell salvage material, and in postoperative cell salvage, the platelet count was low, but significant proportions of platelets were activated, and levels of D-dimer were elevated compared with venous blood. The postoperative salvage material also contained high levels of TAT. The results from this pilot study show the induction of a prothrombotic state following reinfusion of intraoperative, washed cell salvage in recipients undergoing primary elective hip operations. An inflammatory response to reinfusion is also indicated by the raised WCC. Further investigation into the safety of cell salvage is indicated

Objectives

After an injury, the biological reattachment of tendon to bone is a challenge because healing takes place between a soft (tendon) and a hard (bone) tissue. Even after healing, the transition zone in the enthesis is not completely regenerated, making it susceptible to re-injury. In this study, we aimed to regenerate Achilles tendon entheses (ATEs) in wounded rats using a combination of kartogenin (KGN) and platelet-rich plasma (PRP).

Objectives

Mesenchymal stem cells have the ability to differentiate into various cell types, and thus have emerged as promising alternatives to chondrocytes in cell-based cartilage repair methods. The aim of this experimental study was to investigate the effect of bone marrow derived mesenchymal stem cells combined with platelet rich fibrin on osteochondral defect repair and articular cartilage regeneration in a canine model.

We have investigated in vitro the release kinetics and bioactivity of fibroblast growth factor-2 (FGF-2) released from a carrier of fibrin sealant. In order to evaluate the effects of the FGF-2 delivery mechanism on the repair of articular cartilage, full-thickness cylindrical defects, 5 mm in diameter and 4 mm in depth, which were too large to undergo spontaneous repair, were created in the femoral trochlea of rabbit knees. These defects were then filled with the sealant.

Approximately 50% of the FGF-2 was released from the sealant within 24 hours while its original bioactivity was maintained. The implantation of the fibrin sealant incorporating FGF-2 successfully induced healing of the surface with hyaline cartilage and concomitant repair of the subchondral bone at eight weeks after the creation of the defect.

Our findings suggest that this delivery method for FGF-2 may be useful for promoting regenerative repair of full-thickness defects of articular cartilage in humans.

Objectives

Triamcinolone acetonide (TA) is widely used for the treatment of rotator cuff injury because of its anti-inflammatory properties. However, TA can also produce deleterious effects such as tendon degeneration or rupture. These harmful effects could be prevented by the addition of platelet-rich plasma (PRP), however, the anti-inflammatory and anti-degenerative effects of the combined use of TA and PRP have not yet been made clear. The objective of this study was to determine how the combination of TA and PRP might influence the inflammation and degeneration of the rotator cuff by examining rotator cuff-derived cells induced by interleukin (IL)-1ß.

Platelet-leucocyte gel (PLG), a new biotechnological blood product, has hitherto been used primarily to treat chronic ulcers and to promote soft-tissue and bone regeneration in a wide range of medical fields. In this study, the antimicrobial efficacy of PLG against Staphylococcus aureus (ATCC 25923) was investigated in a rabbit model of osteomyelitis. Autologous PLG was injected into the tibial canal after inoculation with Staph. aureus. The prophylactic efficacy of PLG was evaluated by microbiological, radiological and histological examination. Animal groups included a treatment group that received systemic cefazolin and a control group that received no treatment.

Treatment with PLG or cefazolin significantly reduced radiological and histological severity scores compared to the control group. This result was confirmed by a significant reduction in the infection rate and the number of viable bacteria. Although not comparable to cefazolin, PLG exhibited antimicrobial efficacy in vivo and therefore represents a novel strategy to prevent bone infection in humans.

Objectives

The aim of this experimental study on New Zealand’s white rabbits was to investigate the transplantation of autogenous growth plate cells in order to treat the injured growth plate. They were assessed in terms of measurements of radiological tibial varus and histological characteristics.

Objectives

In order to ensure safety of the cell-based therapy for bone regeneration, we examined in vivo biodistribution of locally or systemically transplanted osteoblast-like cells generated from bone marrow (BM) derived mononuclear cells.

Objectives

We aimed to examine the characteristics of deep venous flow in the leg in a cast and the effects of a wearable neuromuscular stimulator (geko; FirstKind Ltd) and also to explore the participants’ tolerance of the stimulator.