In Vivo Study of Osteochondral Defect Regeneration Using Innovative Composite Calcium Phosphate Biocement in a Sheep Model.

This study aimed to clarify the therapeutic effect and regenerative potential of the novel, amino acids-enriched acellular biocement (CAL) based on calcium phosphate on osteochondral defects in sheep. Eighteen sheep were divided into three groups, the treated group (osteochondral defects filled with a CAL biomaterial), the treated group with a biocement without amino acids (C cement), and the untreated group (spontaneous healing). Cartilages of all three groups were compared with natural cartilage (negative control). After six months, sheep were evaluated by gross appearance, histological staining, immunohistochemical staining, histological scores, X-ray, micro-CT, and MRI. Treatment of osteochondral defects by CAL resulted in efficient articular cartilage regeneration, with a predominant structural and histological characteristic of hyaline cartilage, contrary to fibrocartilage, fibrous tissue or disordered mixed tissue on untreated defect (p < 0.001, modified O'Driscoll score). MRI results of treated defects showed well-integrated and regenerated cartilage with similar signal intensity, regularity of the articular surface, and cartilage thickness with respect to adjacent native cartilage. We have demonstrated that the use of new biocement represents an effective solution for the successful treatment of osteochondral defects in a sheep animal model, can induce an endogenous regeneration of cartilage in situ, and provides several benefits for the design of future therapies supporting osteochondral defect healing.

PHB/CHIT Scaffold as a Promising Biopolymer in the Treatment of Osteochondral Defects-An Experimental Animal Study.

Biopolymer composites allow the creation of an optimal environment for the regeneration of chondral and osteochondral defects of articular cartilage, where natural regeneration potential is limited. In this experimental study, we used the sheep animal model for the creation of knee cartilage defects. In the medial part of the trochlea and on the medial condyle of the femur, we created artificial defects (6 × 3 mm2) with microfractures. In four experimental sheep, both defects were subsequently filled with the porous acellular polyhydroxybutyrate/chitosan (PHB/CHIT)-based implant. Two sheep had untreated defects. We evaluated the quality of the newly formed tissue in the femoral trochlea defect site using imaging (X-ray, Computer Tomography (CT), Magnetic Resonance Imaging (MRI)), macroscopic, and histological methods. Macroscopically, the surface of the treated regenerate corresponded to the niveau of the surrounding cartilage. X-ray examination 6 months after the implantation confirmed the restoration of the contour in the subchondral calcified layer and the advanced rate of bone tissue integration. The CT scan revealed a low regenerative potential in the bone zone of the defect compared to the cartilage zone. The percentage change in cartilage density at the defect site was not significantly different to the reference area (0.06-6.4%). MRI examination revealed that the healing osteochondral defect was comparable to the intact cartilage signal on the surface of the defect. Hyaline-like cartilage was observed in most of the treated animals, except for one, where the defect was repaired with fibrocartilage. Thus, the acellular, chitosan-based biomaterial is a promising biopolymer composite for the treatment of chondral and osteochondral defects of traumatic character. It has potential for further clinical testing in the orthopedic field, primarily with the combination of supporting factors.

The first serological evidence of Anaplasma phagocytophilum in horses in Slovakia.

Anaplasma phagocytophilum is the causative agent of granulocytic anaplasmosis. It affects humans and several wild and domesticated mammals, including horses. The aim of our study was a preliminary survey of the occurrence of these re-emerging pathogens in horses in Slovakia. The sera from 200 animals of different ages and both sexes were tested for the presence of A. phagocytophilum antibodies by indirect immunofluorescence assay. Subsequently, detection of the 16S rRNA gene fragment of A. phagocytophilum was attempted by polymerase chain reaction (PCR) in each blood sample. Our results confirmed the presence of specific antibodies in 85 out of 200 individuals (42.5%), but no significant changes were found between the animals of different ages and sexes. However, the PCR analysis did not detect any positive animals. Our data represent one of the highest values of seropositivity to A. phagocytophilum in horses in Central Europe. These results may contribute to a better understanding of the circulation of A. phagocytophilum in this region, thus indicating a potential risk to other susceptible species.