Triamcinolone acetonide (TA) injections are widely used to treat enthesopathy, but they may induce adverse effects such as tendon impairment and rupture. Platelet-rich plasma (PRP) is a blood fraction containing high platelet concentrations and various growth factors that play a role in tissue repair processes. The purpose of this study is to investigate whether TA has deleterious effects on human rotator cuff-derived cells, and if PRP can protect these cells from the effects of TA. Human rotator cuff-derived cells were cultured with and without TA and PRP, and the culture without any additive served as the control. Cell morphology was assessed at days 7 and 21. Cell viability was evaluated at days 1, 7, 14, and 21 by a water-soluble tetrazolium salt assay. Induction of apoptosis was measured by immunofluorescence staining and flow cytometry at day 7. Induction of cleaved caspase-3 was measured by immunofluorescence staining at day 7. The cells cultured with TA had a flattened and polygonal shape at day 7. The cells cultured with both TA and PRP were similar in appearance to control cells. Exposure to TA also significantly decreased cell viability, but cell viability did not decrease when PRP was added along with TA. The number of apoptotic cells increased with TA exposure, while addition of PRP prevented cell apoptosis. In conclusion, the deleterious effect of TA was prevented by PRP, which can be used as a protective agent for patients receiving local TA injections. Keywords: triamcinolone acetonide (TA); platelet-rich plasma (PRP); rotator cuff-derived cells; apoptosis; cell viability Enthesopathy caused by rotator cuff injury clinically impairs joint function. Rotator cuff disease represents a spectrum of pathological conditions ranging from tendinosis to full-thickness tears. Conservative therapy, including rest, physical therapy, non-steroidal anti-inflammatory medications, and steroid injections are the primary treatments for these conditions. 1,2The effectiveness of subacromial steroid injections for treatment of rotator cuff tendinosis has been equivocal. 3,4 Some clinical studies have demonstrated improvement in shoulder function and decrease in shoulder pain following steroid injection.3,5 However, other studies have shown that steroids afford no clinical benefits over those provided by injections of lidocaine alone 4 or physical therapy alone. 6 Triamcinolone acetonide (TA) injections are widely used for treatment of rotator cuff tendinosis, but they may cause tendon impairment and rupture; many cases of tendon rupture after TA injections have been reported. 7-11Despite previous studies on the deleterious histological and biomechanical changes in tendons after TA injections, 8,12 TA administration is still considered to be a conservative treatment option.Platelet-rich plasma (PRP) is an autologs concentration of platelets that contains many growth factors, including platelet-derived growth factor (PDGF), transforming growth factor b (TGF-b), fibroblastic growth factor (FGF), vascular endoth...

We have made three types of poly (DL-lactide-coglycolide) (PLG) scaffolds (porosity: scaffold I 80±0.9%, II 85±0.8%, III 92±0.7%; compression module determined with 10% strain: scaffold I 0.26 MPa, II 0.091 MPa, III 0.0047 MPa). Osteochondral defects made in the femoral condyle of rabbits were treated with these scaffolds and the possibilities of cartilage repair were investigated histologically. At post-operative weeks 6 and 12, histological scores in the groups of scaffolds II and III were significantly higher than the score in the group of scaffold I. Scaffolds II and III, which have higher porosity than scaffold I, allow better migration of bone marrow cells and better replacement of the scaffold with bone and cartilage than scaffold I. This study suggests that higher porosity allowing bone marrow cells to migrate to the scaffold is important in repairing osteochondral defects.Résumé Nous avons réalisé trois types de montage PLG (DL lactide co glycolide) avec des porosités différentes (montage I à 0,9%, montage II à 87 ,8%, montage III 0,7%). Avec le module de compression a été imposée une tension de 10% avec 0,26 MPa au niveau de la pièce I, 0,091 Mpa en montage II et 0,0047 MPa en montage III). Un defect ostéochondral réalisé dans le condyle fémoral d'un lapin a été traité par ces trois procédés avec une possibilité de réparation cartilagineuse. Cette possibilité a été évaluée histologiquement. A 6 et 12 semaines postopératoires, le score histologique dans les groupes II et III sont significativement plus élevés que dans le groupe I. Les pièces II et III qui ont une plus grande porosité que la I permettent une meilleure migration des cellules de la moelle osseuse et une meilleure réparation de l'os et du cartilage que dans le montage I. Cette étude nous permet de penser qu'une porosité plus importante permet la migration plus facile de ces cellules de moelle osseuse lors de la réparation des défects ostéochondraux.

We developed a new porous scaffold made from a synthetic polymer, poly(DL-lactide-co-glycolide) (PLG), and evaluated its use in the repair of cartilage. Osteochondral defects made on the femoral trochlear of rabbits were treated by transplantation of the PLG scaffold, examined histologically and compared with an untreated control group. Fibrous tissue was initially organised in an arcade array with poor cellularity at the articular surface of the scaffold. The tissue regenerated to cartilage at the articular surface. In the subchondral area, new bone formed and the scaffold was absorbed. The histological scores were significantly higher in the defects treated by the scaffold than in the control group (p < 0.05). Our findings suggest that in an animal model the new porous PLG scaffold is effective for repairing full-thickness osteochondral defects without cultured cells and growth factors.

A successful scaffold for use in tendon tissue engineering requires a high affinity for living organisms and the ability to maintain its mechanical strength until maturation of the regenerated tissue. We compared two types of poly(L-lactic acid) (PLLA) scaffolds for use in tendon regeneration, a plain-woven PLLA fabric (fabric P) with a smooth surface only and a double layered PLLA fabric (fabric D) with a smooth surface on one side and a rough (pile-finished) surface on the other side. These two types of fabric were implanted into the back muscles of rabbits and evaluated at three and six weeks after implantation. Histological examination showed collagen tissues were highly regenerated on the rough surface of fabric D. On the other hand, liner cell attachment was seen in the smooth surface of fabric P and fabric D. The total DNA amount was significantly higher in fabric D. Additionally, mechanical examination showed fabric P had lost its mechanical strength by six weeks after implantation, while the strength of fabric D was maintained. Fabric D had more cell migration on one side and less cell adhesion on the other side and maintained its initial strength. Thus, a novel form of double-layered PLLA fabric has the potential to be used as a scaffold in tendon regeneration.

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BackgroundThis study evaluated the application of a layered cell free poly (L-lactic acid) (PLLA) scaffold to regenerate an infraspinatus tendon defect in a rabbit model. We hypothesized that PLLA scaffold without cultivated cells would lead to regeneration of tissue with mechanical properties similar to reattached infraspinatus without tendon defects.MethodsLayered PLLA fabric with a smooth surface on one side and a pile-finished surface on the other side was used. Novel form of layered PLLA scaffold was created by superimposing 2 PLLA fabrics. Defects of the infraspinatus tendon were created in 32 rabbits and the PLLA scaffolds were transplanted, four rabbits were used as normal control. Contralateral infraspinatus tendons were reattached to humeral head without scaffold implantation. Histological and mechanical evaluations were performed at 4, 8, and 16 weeks after operation.ResultsAt 4 weeks postoperatively, cell migration was observed in the interstice of the PLLA fibers. Regenerated tissue was directly connected to the bone composed mainly of type III collagen, at 16 weeks postoperatively. The ultimate failure load increased in a time-dependent manner and no statistical difference was seen between normal infraspinatus tendon and scaffold group at 8 and 16 weeks postoperatively. There were no differences between scaffold group and reattach group at each time of point. The stiffness did not improve significantly in both groups.ConclusionsA novel form of layered PLLA scaffold has the potential to induce cell migration into the scaffold and to bridge the tendon defect with mechanical properties similar to reattached infraspinatus tendon model.

BackgroundIt is important to regenerate the tendon-to-bone interface after rotator cuff repair to prevent re-tears. The cells from torn human rotator cuff were targeted, and their capacity for multilineage differentiation was investigated.MethodsThe edges of the rotator cuff were harvested during arthroscopic rotator cuff repair from nine patients, minced into pieces, and cultured on dishes. Adherent cells were cultured, phenotypically characterized. Then expandability, differentiation potential and gene expression were analyzed.ResultsFlow cytometry revealed that the mesenchymal stem cells (MSC)-related markers CD29, CD44, CD105, and CD166 were positive. However, CD14, CD34, and CD45 were negative. On RT-PCR analyses, the cells showed osteogenic, adipogenic, and chondrogenic potential after 3 weeks of culture under the respective differentiation conditions. In addition, SOX9, type II collagen, and type X collagen expression patterns during chondrogenesis were similar to those of endochondral ossification at the enthesis.ConclusionsThe cells derived from torn human rotator cuff are multipotent mesenchymal stem cells with the ability to undergo multilineage differentiation, suggesting that MSCs form this tissue could be regenerative capacity for potential self-repair.

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