Writing 3D In Vitro Models of Human Tendon within a Biomimetic Fibrillar Support Platform.

Tendinopathies are poorly understood diseases for which treatment remains challenging. Relevant in vitro models to study human tendon physiology and pathophysiology are therefore highly needed. Here we propose the automated 3D writing of tendon microphysiological systems (MPSs) embedded in a biomimetic fibrillar support platform based on cellulose nanocrystals (CNCs) self-assembly. Tendon decellularized extracellular matrix (dECM) was used to formulate bioinks that closely recapitulate the biochemical signature of tendon niche. A monoculture system recreating the cellular patterns and phenotype of the tendon core was first developed and characterized. This system was then incorporated with a vascular compartment to study the crosstalk between the two cell populations. The combined biophysical and biochemical cues of the printed pattern and dECM hydrogel were revealed to be effective in inducing human-adipose-derived stem cells (hASCs) differentiation toward the tenogenic lineage. In the multicellular system, chemotactic effects promoted endothelial cells migration toward the direction of the tendon core compartment, while the established cellular crosstalk boosted hASCs tenogenesis, emulating the tendon development stages. Overall, the proposed concept is a promising strategy for the automated fabrication of humanized organotypic tendon-on-chip models that will be a valuable new tool for the study of tendon physiology and pathogenesis mechanisms and for testing new tendinopathy treatments.

Biocompatibility of hydrogel derived from equine tendon extracellular matrix in horses subcutaneous tissue.

Tendinopathies account for a substantial proportion of musculoskeletal injuries. To improve treatment outcomes for partial and total tendon ruptures, new therapies are under investigation. These include the application of mesenchymal stem cells (MSCs) and biocompatible scaffolds derived from the Extracellular Matrix (ECM). Synthetic polymer hydrogels have not demonstrated results as promising as those achieved with ECM hydrogels sourced from the original tissue. This study aimed to evaluate the biocompatibility of a hydrogel formulated from equine tendon ECM. Six horses were administered three subcutaneous doses of the hydrogel, with a saline solution serving as a control. Biopsies were conducted on days 7, 14, and 56 post-application to gauge the hydrogel's impact. Throughout the experiment, the horse's physical condition remained stable. Thermographic analyses revealed a temperature increase in the treated groups compared to the control group within the initial 12 h. The von Frey test, used to measure the mechanical nociceptive threshold, also showed significant differences between the treated group and the control group at 6 h, 21 days, and 28 days. Histopathological analyses identified an inflammatory response on day 7, which was absent on days 14 and 56. Transmission electron microscopy indicated a decrease in inflammatory cellularity, while immunohistochemistry staining suggested an increased presence of inflammatory factors on day 14. In summary, the hydrogel is easily injectable, triggers a temporary local inflammatory response, and integrates into the adjacent tissue from day 14 onwards.

Production of Cytotoxic Antibodies After Intra-Articular Injection of Allogeneic Synovial Membrane Mesenchymal Stem Cells With and Without LPS Administration.

Allogeneic mesenchymal stem cells (MSC) are widely used in clinical routine due to the shorter expansion time and reliability of its quality. However, some recipients can produce alloantibodies that recognize MSCs and activate the immune system, resulting in cell death. Although antibody production was already described after MSC injection, no previous studies described the immune response after intra-articular MSC injection in acute synovitis. This study aimed to evaluate the influence of inflammation on immune response after single and repeated intra-articular injections of synovial membrane MSC (SMMSC). Horses were divided in three groups: control group (AUTO) received autologous synovial membrane MSCs; whereas group two (ALLO) received allogeneic SMMSCs and group three (ALLO LPS) was submitted to acute experimental synovitis 8 h before SMMSCs injection. The procedure was repeated for all groups for 28 days. Physical and lameness evaluations and synovial fluid analysis were performed. Sera from all animals were obtained before and every 7 days after each injection up to 4 weeks, to perform microcytotoxicity assays incubating donor SMMSCs with recipients' sera. The first injection caused a mild and transient synovitis in all groups, becoming more evident and longer in ALLO and ALLO LPS groups after the second injection. Microcytotoxicity assays revealed significant antibody production as soon as 7 days after SMMSC injection in ALLO and ALLO LPS groups, and cytotoxicity scores of both groups showed no differences at any time point, being equally different from AUTO group. Although inflammation is capable of inducing MHC expression in MSCs, which enhances immune recognition, cytotoxicity scores were equally high in ALLO and ALLO LPS groups, making it difficult to determine the potentiation effect of inflammation on antibody production. Our findings suggest that inflammation does not display a pivotal role in immune recognition on first allogeneic MSC injection. In a translational way, since specific antibodies were produced against MSCs, patients that need more than one MSC injection may benefit from a first allogeneic injection followed by subsequent autologous injections.

Evaluation of changes in microbiota after fecal microbiota transplantation in 6 diarrheic horses.

The purpose of this study was to characterize the fecal microbiota of horses with acute and chronic diarrhea before and after fecal microbiota transplantation (FMT). Six client-owned horses with acute and chronic diarrhea received FMT from 2 healthy donor horses. Microbiota analysis using next-generation sequencing was performed on fecal samples collected before and 2 and 7 d after FMT. Signs of diarrhea improved in 4 horses, whereas the remaining 2 horses did not survive. There was a significant difference in the number of bacterial species between donors and recipients (P < 0.05). The Order Lactobacillales and the genera Lactobacillus, Intestinimonas, and Streptococcus were increased in the microbiota of diarrheic horses, and Saccharofermentans genus increased in healthy donors. The results suggest that FMT from the healthy donors was not effective over a 7-day period as it did not change the fecal microbiota of the diarrheic horses. Further research to improve the efficacy of FMT in horses is needed.

Évaluation des modifications du microbiote après une transplantation de microbiote fécal chez six chevaux avec la diarrhée. Le but de cette étude était de caractériser le microbiote fécal des chevaux souffrant de diarrhée aiguë et chronique avant et après la transplantation de microbiote fécal (FMT). Six chevaux souffrant de diarrhée aiguë et chronique et appartenant à des clients ont reçu des FMT provenant de deux chevaux donneurs en bonne santé. Une analyse du microbiote a été réalisée sur des échantillons fécaux prélevés avant et 2 et 7 jours après la FMT. Les signes de la diarrhée se sont améliorés chez 4 des 6 chevaux, tandis que les deux autres n'ont pas survécu. Il y avait une différence significative dans la richesse bactérienne entre les donneurs et les récipients (P < 0,05). L'ordre Lactobacillales, et les genres Lactobacillus, Intestinimonas et Streptococcus ont été associés au microbiote des chevaux diarrhéiques et le genre Saccharofermentanes à celui des donneurs sains. Les résultats suggèrent que la FMT n'a pas réussi à changer le microbiote fécal des chevaux diarrhéiques sur une période de 7 jours. Des recherches supplémentaires pour améliorer l'efficacité de la FMT chez les chevaux sont nécessaires.(Traduit par les auteurs).

In Vitro Biological Performance of Alginate Hydrogel Capsules for Stem Cell Delivery.

Encapsulation of biological components in hydrogels is a well described method for controlled drug delivery of proteins, tissue engineering and intestinal colonization with beneficial bacteria. Given the potential of tissue engineering in clinical practice, this study aimed to evaluate the feasibility of encapsulation of adipose tissue-derived mesenchymal stem cells (MSCs) of mules in sodium alginate. We evaluated capsule morphology and cell viability, immunophenotype and release after encapsulation. Circular and irregular pores were observed on the hydrogel surface, in which MSCs were present and alive. Capsules demonstrated good capacity of absorption of liquid and cell viability was consistently high through the time points, indicating proper nutrient diffusion. Flow cytometry showed stability of stem cell surface markers, whereas immunohistochemistry revealed the expression of CD44 and absence of MHC-II through 7 days of culture. Stem cell encapsulation in sodium alginate hydrogel is a feasible technique that does not compromise cell viability and preserves their undifferentiated status, becoming a relevant option to further studies of tridimensional culture systems and in vivo bioactive agents delivery.

Evaluation of alginate hydrogel encapsulated mesenchymal stem cell migration in horses.

Osteoarthritis is an incapacitating disease characterized by pain and a progressive decrease in joint mobility. The implantation of mesenchymal stem cells (MSCs) has shown promising results for its treatment. The challenge remains to keep the cells longer at the site of action, increasing their therapeutic potential. The aim of this study was to evaluate the effectiveness of the Qtracker® 655 nanocrystal marking on allogeneic synovial membrane (SM) MSCs, encapsulated in alginate hydrogel, evaluating the migration of these cells. The 10 radiocarpal joints were submitted to arthroscopic surgery (D0), divided into two groups. The chondral defect was treated according to the group: GA free-labelled MSCSM and GB labelled MSCSM microcapsules. Seven days after lesion induction and implantation of labelled cells, biopsies of the lesion site were performed in two animals, and fragments of SM and joint capsule also collected, which were frozen and later processed for fluorescence microscopy. The synovial fluid of the three animals was analyzed by flow cytometry three times - 3, 7 and 21 days after application. The cellular marking with the nanocrystals allowed the visualization of the cells in cartilage, synovial membrane, synovial fluid and articular capsule, but with a predilection for the synovial membrane and the lesion site was scarce. The labelled MSCSM in microcapsules were scarce in the synovial fluid and could be related to the small quantity of MSCs leaving the pores of the microcapsules, also favorable results, as the cells release paracrine effects acting for a long period until the cellular differentiation.

Physiotherapy protocol during initial postoperative period of arthroscopy in horses / Protocolo fisioterápico durante o período pós-operatório inicial de cirurgia artroscópica em equinos

This study evaluated the effects of a physiotherapy protocol applied in joints with osteochondritis dissecans submitted to arthroscopy. Twelve horses totaling twenty joints were used and divided into two uniform groups, according to articular lesion grade. Treated Group (TG) received the physiotherapy protocol (cryotherapy, passive rage motion and controlled exercise) that initiate just after anesthetic recovery and extended for five days. Control Group (CG) remained resting in stall during the same period. Physical examination and synovial fluid analysis were used to evaluate the treatment. The synovial fluid examination consisted of physical analysis (color, aspect, and viscosity), mucin clot evaluation, Serum Amyloid A, Prostaglandin E2 and urea concentration. Synovial samples were collected by arthrocentesis at the beginning of the surgical procedure (D1), 48 hours (D3) and 96 hours (D5) after surgery. Before arthroscopy and daily during the postoperative period joints were evaluated by physical exam: superficial temperature (°C), range of motion (degrees) and circumference (centimeters). The joint physical examination showed no significant difference between groups and neither along the days for the same group. The parameters of synovial fluid showed difference over the moments in each group but didn't have difference between groups. Color and aspect had the same patterns across moments, in CG fluid had significant change when compared D1 with D3 (color and aspect: p<0.001) and D5 (color: p<0.001; aspect: p<0.05) becoming mostly bloody and cloudy in D3 and D5. However in TG the difference was significant just between D1 and D3 (color and aspect: p<0.05), showing an improvement of synovial fluid in D5 (color and aspect: p<0.05). Viscosity and mucin clot evaluation showed significant change in CG between D1 and D3 (viscosity: p<0.01; mucin clot: p<0.05) and between D1 and D5 (viscosity: p<0.01;mucin clot: p<0.01). In TG no significant difference of viscosity and mucin clot was observed over the moments, showing an early improvement of synovial fluid quality. The Serum Amyloid A concentration showed an extremely significant increase in CG (p<0.001) when compared D1 (1217.13±664.47µg/mL) and D3 (42423.80±52309.31µg/mL). The comparison between D1 and D5 in CG, and across moments in TG, had no statistical difference. The PGE2 eicosanoid remained statistically unchanged all over the time. Urea showed significant increase in D3 when compared to D1 (p<0.001) in CG, and had no variation in TG. The physiotherapy protocol minimized the inflammatory mediators and provided minor alterations in synovial fluid after arthroscopy.(AU)

Este estudo avaliou os efeitos de um protocolo fisioterápico, aplicado em articulações com osteocondrite dissecante, submetidas à artroscopia. Foram utilizados 12 cavalos, totalizando 20 articulações, divididas em dois grupos homogêneos de acordo com a graduação da lesão articular. O grupo tratado (GT) recebeu o protocolo fisioterápico (crioterapia, movimentação passiva e exercício controlado) que se iniciou imediatamente após a recuperação anestésica e se estendeu por cinco dias. O grupo controle (GC) permaneceu em repouso na baia, pelo mesmo período. Exame físico da articulação e análise do líquido sinovial foram utilizados para avaliar o tratamento. O exame do líquido sinovial consistiu em análise física (cor, aspecto e viscosidade), avaliação do coágulo de mucina e concentrações de amiloide sérica A, prostaglandina E2 e ureia. Amostras de líquido sinovial foram colhidas por artrocentese no início do procedimento cirúrgico (D1) e após 48 (D3) e 96 horas (D5) do procedimento cirúrgico. Antes da artroscopia e diariamente no período pós-operatório, as articulações foram avaliadas por exame físico: temperatura superficial (°C), ângulo de flexão (graus), circunferência (centímetros). A avaliação física das articulações não apresentou diferença significativa entre os grupos nem ao longo dos dias em cada grupo. Nas análises do líquido sinovial, observou-se uma variação diferente entre os momentos em cada grupo porém sem diferença significativa entre os grupos. A cor e o aspecto tiveram resultados semelhantes ao longo do tempo, no GC houve uma alteração significativa quando comparados D1 e D3 (cor e aspecto: p<0,001) e D1 e D5 (cor: p<0,001; aspecto: p<0,05) tornando-se sanguinolento e turvo na maioria das amostras em D3 e D5. Já no GT, houve diferença significativa apenas entre D1 e D3 (cor e aspecto: p<0,05), demonstrando melhora no líquido sinovial em D5 (cor e aspecto: p<0,05). A viscosidade e o coágulo de mucina apresentou alteração significativa no GC entre D1 e D3 (viscosidade: p<0,01; coágulo de mucina: p<0,05) e entre D1 e D5 (viscosidade e coágulo de mucina: P<0,01). No grupo tratado não foram observadas alterações significativas em viscosidade e coágulo de mucina, ao longo dos momentos, demonstrando uma melhora precoce na qualidade do líquido sinovial. A amiloide sérica A apresentou um aumento extremamente significante no GC (p<0,001) quando comparados D1 (1217,13±664,47µg/dL) e D3 (42423,80±52309,31µg/dL). Quando comparados D1 e D5 no GC e ao longo do tempo no GT não foram observadas diferenças significativas. A concentração de PGE2 permaneceu sem alterações. As mensurações de ureia apresentaram aumento significativo em D3 quando comparado a D1 (p<0,001) no GC e não apresentou variação no GT. O protocolo fisioterápico minimizou os mediadores inflamatórios e proporcionou menor alteração do líquido sinovial após artroscopia.(AU)