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BackgroundAdipose tissue is a promising source of mesenchymal stromal cells (MSCs) for the treatment of tendon disease. The goal of this study was to assess the effect of a single intralesional implantation of adipose tissue-derived mesenchymal stromal cells (AT-MSCs) on artificial lesions in equine superficial digital flexor tendons (SDFTs).MethodsDuring this randomized, controlled, blinded experimental study, either autologous cultured AT-MSCs suspended in autologous inactivated serum (AT-MSC-serum) or autologous inactivated serum (serum) were injected intralesionally 2 weeks after surgical creation of centrally located SDFT lesions in both forelimbs of nine horses. Healing was assessed clinically and with ultrasound (standard B-mode and ultrasound tissue characterization) at regular intervals over 24 weeks. After euthanasia of the horses the SDFTs were examined histologically, biochemically and by means of biomechanical testing.ResultsAT-MSC implantation did not substantially influence clinical and ultrasonographic parameters. Histology, biochemical and biomechanical characteristics of the repair tissue did not differ significantly between treatment modalities after 24 weeks. Compared with macroscopically normal tendon tissue, the content of the mature collagen crosslink hydroxylysylpyridinoline did not differ after AT-MSC-serum treatment (p = 0.074) while it was significantly lower (p = 0.027) in lesions treated with serum alone. Stress at failure (p = 0.048) and the modulus of elasticity (p = 0.001) were significantly lower after AT-MSC-serum treatment than in normal tendon tissue.ConclusionsThe effect of a single intralesional injection of cultured AT-MSCs suspended in autologous inactivated serum was not superior to treatment of surgically created SDFT lesions with autologous inactivated serum alone in a surgical model of tendinopathy over an observation period of 22 weeks. AT-MSC treatment might have a positive influence on collagen crosslinking of remodelling scar tissue. Controlled long-term studies including naturally occurring tendinopathies are necessary to verify the effects of AT-MSCs on tendon disease.Electronic supplementary materialThe online version of this article (doi:10.1186/s13287-017-0564-8) contains supplementary material, which is available to authorized users.

A severe hemorrhagic shock in patients could result in initial delayed fracture healing and needs special attention. We plan to conduct a prospective, observational clinical research study to analyze if delayed fracture healing occurs in patients after severe blood loss.

Biological factors such as TGF–β3 are possible supporters of the healing process in chronic rotator cuff tears. In the present study, electrospun chitosan coated polycaprolacton (CS–g–PCL) fibre scaffolds were loaded with TGF–β3 and their effect on tendon healing was compared biomechanically and histologically to unloaded fibre scaffolds in a chronic tendon defect rat model. The biomechanical analysis revealed that tendon–bone constructs with unloaded scaffolds had significantly lower values for maximum force compared to native tendons. Tendon-bone constructs with TGF–β3-loaded fibre scaffolds showed only slightly lower values. In histological evaluation minor differences could be observed. Both groups showed advanced fibre scaffold degradation driven partly by foreign body giant cell accumulation and high cellular numbers in the reconstructed area. Normal levels of neutrophils indicate that present mast cells mediated rather phagocytosis than inflammation. Fibrosis as sign of foreign body encapsulation and scar formation was only minorly present. In conclusion, TGF–β3-loading of electrospun PCL fibre scaffolds resulted in more robust constructs without causing significant advantages on a cellular level. A deeper investigation with special focus on macrophages and foreign body giant cells interactions is one of the major foci in further investigations.

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Acute and chronic rotator cuff tears remain challenging for therapy. A wide range of therapeutic approaches were developed but re-tears and postoperative complications occur regularly. Especially in elderly people, the natural regeneration processes are decelerated, and graft materials are often necessary to stabilize the tendon-to-bone attachment and to improve the healing process. We here investigated in a small animal model a newly developed electrospun polycaprolactone fiber implant coated with a chitosan-polycaprolactone graft copolymer and compared these implants biomechanically and histologically with either a commercially available porous polyurethane implant (Biomerix 3D Scaffold) or suture-fixed tendons. Fifty-one rats were divided into three groups of 17 animals each. In the first surgery, the left infraspinatus tendons of all rats were detached, and the animals recovered for 4 weeks. In the second surgery, the tendons were fixed with suture material only (suture-fixed group; n = 17), whereas in the two experimental groups, the tendons were fixed with suture material and the polyurethane implant (Biomerix scaffold group; n = 17) or the modified electrospun polycaprolactone fiber implant (CS-g-PCL scaffold group; n=17), respectively. The unaffected right infraspinatus tendons were used as native controls. After a recovery of 8 weeks, all animals were clinically inconspicuous. In 12 animals of each group, repaired entheses were biomechanically tested for force at failure, stiffness, and modulus of elasticity, and in five animals, repaired entheses were analyzed histologically. Biomechanically, all parameters did not differ statistically significant between both implant groups, and the entheses failed typically at the surgical site.However, with respect to the force at failure, the median values of the two implant groups were smaller than the median value of the suture-fixed group. Histologically, the modified polycaprolactone fiber implant showed no acute inflammation processes, a good infiltration with cells, ingrowth of blood vessels and tendinous tissue, and a normal fibrous ensheathment. Further improvement of the implant material could be achieved by additional implementation of drug delivery systems. Therewith, the used CS-g-PCL fiber mat is a promising basic material to reach the goal of a clinically usable graft for rotator cuff tear repair.Elmar Willbold and Mathias Wellmann contributed equally to this work

A combined lesion of the AC ligaments and the DTF resulted in a quantitatively small but significant increase in anterior rotation and a tendency in lateral translation of the clavicle in relation to the acromion. These differences were quantitatively small, so that the clinical relevance of the stabilization effect of combined AC ligaments and DTF injuries is questionable.

Conventionally, transfemoral amputees are treated with a shaft prosthesis fitted over the residual limb. To improve the quality of life of such patients, in particular those with complications relating to conventional attachment (e.g., skin irritation, stump ulcers, and poor motor-control with short stumps), osseointegrated prosthesis fixation implants have been developed and implanted in a limited population of patients. To assess possible damage to the implant/prosthesis during falling scenarios, the loads in high-risk situations were estimated using a multi-body simulation of motion. Five falling scenarios were identified and performed by healthy volunteer wearing safety equipment. Kinematic data and ground reaction forces were captured as input for the inverse-dynamics-based simulations, from which the forces and moments at a typical implant-prosthesis interface location were computed. The estimated peak loads in all five scenarios were of a magnitude that could lead to bone fracture. The largest peak force observed was 3274 ± 519 N, with an associated resultant moment of 176 ± 55 Nm on the prosthesis-implant interface. A typical femur is prone to fracture under this load, thus illustrating the need for a safety-release element in osseointegrated prosthesis fixation.