Search

Background High-power laser therapy gained popularity recently as a regenerative treatment for tendinitis and desmitis in the horse. However, studies evaluating the effects of laser therapy on tissue repair at the histological level in large mammals are lacking. Objectives To evaluate the effects of high-power laser therapy on suspensory desmitis healing, using a model of suspensory ligament branch injury. Study design In vivo experiments. Methods Standardised lesions were surgically induced in all four lateral suspensory branches of 12 healthy Warmblood horses. Laser therapy (class 4, 15W) was applied daily on two of four induced lesions for four consecutive weeks. Horses were randomly assigned to either short-term study (horses were sacrificed after 4 weeks) or long-term study (6 months). Suspensory ligament samples were scored after staining with haematoxylin-eosin and immunostaining for collagen 1- collagen 3- and factor VIII. Results In the short-term study, significantly better (lower) scores for variation in density (17% above cut-off score in treated lesions vs. 31% above cut-off score in controls, P = .03), shape of nuclei (54% vs 92%, P = .02), fibre alignment (32% vs 75%, P = .003) and fibre structure (38% vs 71%, P = .02) were found in laser-treated lesions when compared to controls. Collagen 3 expression was significantly higher (32% vs 19%, P = .006) in control lesions. In both short- and long-term studies combined, parameters lesion size (44% vs 56%, P = .02) and shape of nuclei (53% vs 84%, P = .05) scored significantly better in treated lesions. Long-term, significantly better (lower) scores were found in the laser-treated group for lesion size (15% vs 45%, P = .008) and a higher percentage above cut-off score for density of the nuclei (27% vs 9%, P = .02), compared to controls. Main limitations The model of suspensory branch injury is not an exact representation of clinical overstrain lesions. Conclusions These results suggest that high-power laser therapy enables better lesion healing than conservative treatment.

Objective Folate receptor beta (FR-β) has been used as a clinical marker and target in multiple inflammatory diseases, including osteoarthritis (OA) and rheumatoid arthritis (RA). However, the conditions under which FR-β+ macrophages arise remain unclear and could be affected by corticosteroids. Therefore, we studied FR-β expression in vitro in macrophage subtypes and determined their response to triamcinolone acetonide (TA), a clinically often-used corticosteroid. Design Human monocyte–derived macrophages were differentiated to the known M0, M1, or M2 macrophage phenotypes. The phenotype and FR-β expression and plasticity of the macrophage subtypes were determined using flow cytometry, reverse transcription-quantitative polymerase chain reaction (RT-qPCR), and enzyme-linked immunosorbent assay (ELISA). Results FR-β expression was low in granulocyte-macrophage colony-stimulating factor (GM-CSF)-generated (M1-like) macrophages and high in macrophage colony-stimulating factor (M-CSF)-generated (M0 and M2-like) macrophages. FR-β expression remained high once the M0 or M2 macrophages were stimulated with pro-inflammatory stimuli (interferon-γ plus lipopolysaccharide) to induce M1-like macrophages. On the contrary, anti-inflammatory TA treatment skewed GM-CSF macrophage differentiation toward an M2 and FR-β+ phenotype. Conclusions As corticosteroids skewed monocytes toward an FR-β-expressing, anti-inflammatory phenotype, even in an M1 priming GM-CSF environment, FR-β has potential as a biomarker to monitor success of treatment with corticosteroids. Without corticosteroid treatment, M-CSF alone induces high FR-β expression which remains high under pro-inflammatory conditions. This explains why pro-inflammatory FR-β+ macrophages (exposed to M-CSF) are observed in arthritis patients and correlate with disease severity.

Bone has great self-healing capacity, but above a certain critical size, bone defects will not heal spontaneously, requiring intervention to achieve full healing. Among the synthetic calcium phosphate (CaP) bone replacement materials, brushite (CaHPO4·2H2O)-based materials are of particular interest because of their degree of solubility and the related high potential to promote bone regeneration after dissolution. They can be produced tailor-made using modern three-dimensional (3D) printing technology. Although this type of implant has been widely tested in vitro, there are only limited in vivo data and less so in a relevant large animal model. In this study, material properties of a 3D-printed brushite-based scaffold are characterized, after which the material is tested by in vivo orthotopic implantation in the equine tuber coxae for 6 months. The implantation procedure was easy to perform and was well tolerated by the animals, which showed no detectable signs of discomfort. In vitro tests showed that compressive strength along the vertical axis of densely printed material was around 13 MPa, which was reduced to approximately 8 MPa in the cylindrical porous implant. In vivo, approximately 40% of the visible volume of the implants was degraded after 6 months and replaced by bone, showing the capacity to stimulate new bone formation. Histologically, ample bone ingrowth was observed. In contrast, empty defects were filled with fibrous tissue only, confirming the material’s osteoconductive capacity. It is concluded that this study provides proof that the 3D-printed brushite implants were able to promote new bone growth after 6 months’ implantation in a large animal model and that the new equine tuber coxae bone model that was used is a promising tool for bone regeneration studies. El hueso tiene una gran capacidad de autocuración, pero por encima de un cierto tamaño crítico, los defectos óseos no se curan espontáneamente, por lo que es necesario intervenir para lograr una curación completa. Entre los materiales sintéticos de sustitución ósea de fosfato de calcio (CaP), los materiales a base de brusquitos (CaHPO4-2H2O) son de particular interés por su grado de solubilidad y el elevado potencial que presentan para promover la regeneración ósea después de la disolución. Pueden producirse a medida utilizando la moderna tecnología de impresión tridimensional (3D). Aunque este tipo de implante ha sido ampliamente probado in vitro, sólo hay datos limitados in vivo y menos en un modelo relevante de animal grande. En este estudio se caracterizan las propiedades del material de un andamiaje tridimensional impreso a base de grafito, tras lo cual el material se prueba mediante la implantación ortotópica in vivo en el tubérculo equino coxae durante 6 meses. El procedimiento de implantación fue fácil de realizar y fue bien tolerado por los animales, que no mostraron ningún signo detectable de molestia. Las pruebas in vitro demostraron que la resistencia a la compresión a lo largo del eje vertical del material densamente impreso era de alrededor de 13 MPa, que se redujo a aproximadamente 8 MPa en el implante cilíndrico poroso. En vivo, aproximadamente el 40% del volumen visible de los implantes se degradó después de 6 meses y fue reemplazado por hueso, lo que demuestra la capacidad de estimular la formación de nuevo hueso. Histológicamente, se observó un amplio crecimiento del hueso. En cambio, los defectos vacíos se llenaron sólo con tejido fibroso, confirmando la capacidad osteoconductiva del material. Se llega a la conclusión de que este estudio aporta pruebas de que los implantes de grafito tridimensional fueron capaces de promover el crecimiento de nuevo hueso después de 6 meses de implantación en un modelo de animal grande y que el nuevo modelo de hueso de tubérculo equino coxae que se utilizó es una herramienta prometedora para los estudios de regeneración ósea. Universidad Nacional, Costa Rica Escuela de Medicina Veterinaria

Aim: The horse joint, due to its similarity with the human joint, is the ultimate model for translational articular cartilage repair studies. This study was designed to determine the critical size of cartilage defects in the equine carpus and serve as a benchmark for the evaluation of new cartilage treatment options. Material and Methods: Circular full-thickness cartilage defects with a diameter of 2, 4, and 8 mm were created in the left middle carpal joint and similar osteochondral (3.5 mm in depth) defects in the right middle carpal joint of 5 horses. Spontaneously formed repair tissue was examined macroscopically, with MR and mu CT imaging, polarized light microscopy, standard histology, and immunohistochemistry at 12 months. Results: Filling of 2 mm chondral defects was good (77.8 +/- 8.5%), but proteoglycan depletion was evident in Safranin-O staining and gadolinium-enhanced MRI (T-1Gd). Larger chondral defects showed poor filling (50.6 +/- 2.7% in 4 mm and 31.9 +/- 7.3% in 8 mm defects). Lesion filling in 2, 4, and 8 mm osteochondral defects was 82.3 +/- 3.0%, 68.0 +/- 4.6% and 70.8 +/- 15.4%, respectively. Type II collagen staining was seen in 9/15 osteochondral defects but only in 1/15 chondral defects. Subchondral bone pathologies were evident in 14/15 osteochondral samples but only in 5/15 chondral samples. Although osteochondral lesions showed better neotissue quality than chondral lesions, the overall repair was deemed unsatisfactory because of the subchondral bone pathologies. Conclusion: We recommend classifying 4 mm as critical osteochondral lesion size and 2 mm as critical chondral lesion size for cartilage repair research in the equine carpal joint model.