Osteochondral regeneration remains a major clinical challenge due to the complex architecture and biomechanical demands of the osteochondral unit. Bioactive hydrogels have emerged as promising materials capable of supporting repair through their capacity to mimic the extracellular matrix (ECM), enable cell encapsulation, and deliver bioactive cues. However, recent insights reveal that simply engineering hydrogels for structural and cellular support is insufficient. A new paradigm is emerging—one that embraces the complexity of the osteochondral niche by integrating immunomodulatory and mechanobiological cues into biomaterial design. In particular, the hydrogel’s capacity to modulate macrophage polarization and support the immunoregulatory function of mesenchymal stem cells (MSCs) is critical to orchestrate regenerative outcomes. Simultaneously, the mechanical properties of hydrogels—such as stiffness, porosity, and viscoelasticity—can profoundly influence stem cell fate and local tissue morphogenesis. This review discusses recent advances in hydrogel-based strategies for osteochondral repair, highlighting the interplay between immunological signals and the mechanical microenvironment, and calls for a shift from reductionist tissue-engineering approaches to systems-level design of tunable, immuno-mechanobiological microenvironments.

Strategies to repair the meniscus have achieved limited success; thus, a cell-based therapy combined with an appropriate biocompatible scaffold could be an interesting alternative to overcome this issue. The aim of this project is to analyze different cell populations and a collagen gel scaffold as a potential source for meniscus tissue engineering applications. Dermal fibroblasts (DFs) and mesenchymal stem cells (MSCs) isolated from adipose tissue (ASCs) or bone marrow (BMSCs) were analyzed. Two different fibro-chondrogenic media, M1 and M2, were tested, and qualitative and quantitative analyses were performed. Significant increases in glycosaminoglycans (GAGs) production and in fibro-cartilaginous marker expression were observed in MSCs in the presence of M1 medium. In addition, both ASCs and BMSCs cultured in M1 medium were used in association with the collagen hydrogel (MSCs-SCF) for the development of an in vitro meniscal-like tissue. Significant up-regulation in GAGs production and in the expression of aggrecan, collagen type I, and collagen type II was observed in BMSCs-SCF. This study improves knowledge of the potential of combining undifferentiated MSCs with a collagen gel as a new tissue engineering strategy for meniscus repair.

This study provides a morphological characterization of the thigh and Semimembranosus muscle (SM) of the Nero di Lomellina (NL) pig, considering two different rearing periods, December-October (rearing period 1) and September-July (rearing period 2), and using a commercial crossbreed (CH) as a reference. Fat content in the thigh was evaluated using computed tomography, while SM characteristics were assessed by comparing muscle fiber area, density, and total number. Fiber type composition was determined by immunofluorescence and molecular analyses through the localization and expression of myosin isoforms, including MyHC I, MyHC IIb, and MyHC IIa/x (red slow oxidative, white fast glycolytic, and intermediate fast oxidative glycolytic fibers, respectively). Additionally, physicochemical analyses were conducted to assess muscle quality. The results showed that both breeds had higher intermuscular fat deposition in the rearing period 2. In period 1, NL pigs exhibited larger muscle fibers than CH pigs, whereas no differences were observed in period 2. Immunofluorescence revealed that CH pigs in period 2 had a higher proportion of red and intermediate fibers, while NL pigs showed no significant changes in fiber composition related to the rearing period. In conclusion, lower temperatures in period 2 promoted an oxidative phenotype in CH, whereas NL pigs showed greater stability across rearing periods and better adaptability to temperature fluctuations. These findings suggest that NL pigs exhibit greater resilience to environmental changes, supporting previous studies on breed-specific responses to temperature variation.

Knee osteoarthritis (OA) and obesity are closely linked, with obesity being the primary risk factor for OA. This study used the medial meniscus of sows (250 kg, 4-6 years old) as a model for spontaneous OA, comparing them to lighter pigs (110 kg, 7-8 months old). The joints were collected according to the 3Rs principles (Replacement, Reduction and Refinement) and compared using macroscopic and microscopic analyses, as well as advanced imaging techniques. The results revealed more severe pathological changes in the sows. Micro-computed tomography analyses showed thickening of radial tie fibers in the sows, with volume fraction remaining similar between light pigs and sows. The highest percentage of tie fibers was found in the posterior horn. Magnetic resonance imaging did not detect any medial meniscal lesions. Histological analyses of the meniscal matrix confirmed disorganized collagen fibers and compromised matrix integrity. Additionally, Raman spectral analyses and immunofluorescence on the posterior horn, which is the most susceptible region for OA, revealed that light pigs exhibited a trend towards higher collagen crosslink ratios than sows, indicating differences in matrix maturity, particularly in the inner region. Finally, Substance P-positive nerve fibers grouped into corpuscles and concentrated in the outer third of the menisci in the sows, whereas in light pigs, only nerve fibers were observed. In conclusion, this study demonstrates that sows, develop spontaneous meniscal alterations and suggests that sows could be utilized as a sustainable animal model for studying OA providing insights into the relationship between obesity and joint health.

The eye is a sensitive target of sublethal stress in aquaculture-reared fish due to its direct exposure to the aquatic environment. This study tested a photoelectrocatalytic (PEC) water treatment system, integrated into a standard recirculating aquaculture system (RAS), to improve water quality and evaluated ocular health in Oncorhynchus mykiss (rainbow trout) reared at 30 kg/m³ for 28 days, with particular emphasis on the cornea as an indicator of fish welfare. Ocular analyses focused on the cornea and retina, two anatomically and functionally distinct structures. PEC significantly reduced ammonia levels and modulated nitrate concentrations compared to the control group (CTR), represented by a standard RAS. No differences in growth performance or body condition were observed between groups. Corneal integrity was assessed using optical coherence tomography, histology, and mucous cell staining to evaluate epithelial structure and protective responses. Corneal tissue was examined to detect local oxidative effects through morphological analysis and immunohistochemistry for 8-hydroxy-2′-deoxyguanosine (8-OHdG). Alcian Blu–Periodic Acid–Schiff (AB–PAS) staining did not reveal significant differences in mucin-producing cells among groups. CTR fish exhibited epithelial disruption and increased 8-OHdG immunoreactivity, whereas fish reared in the RAS equipped with the PEC system, ensuring improved water quality, showed preserved corneal architecture despite mild oxidative stress. Molecular analysis of ocular tissues revealed no differential expression of oxidative stress-related genes, such as GPx1, GR, or sod1, in the two groups. Overall, these findings support the use of the cornea as a sensitive indicator of sublethal environmental stress in farmed fish and suggest that PEC treatment may contribute to improved water quality management and welfare monitoring in intensive aquaculture systems.

A feeding trial with alternative protein sources was conducted in gilthead seabream ( Sparus aurata , L.) broodstock fed a control diet and two diets with 5% or 10% inclusion levels of a blend of novel ingredients. The blend is composed of 40% insect ( Hermetia illucens ), 10% duckweed ( Lemna minor ), 45% Nannochloropsis gaditana , and 5% Alaria esculenta meal dry biomass. The animals were reared in a recirculating aquaculture system and administered the experimental diets 3 months before spawning and for a total of 7 months. Fertilized eggs were incubated until hatching and newly hatched larvae were monitored until the yolk sac absorption stage. High inclusion (HI; 10%) of novel ingredients to broodstock resulted in a significantly higher hatching rate, while both groups fed novel ingredients produced offspring with significantly higher survival until the end of the yolk sac stage compared to offspring from parents fed the control diet ( p < 0.05). The inclusion of the protein blend at any level did not produce differences in larval growth. Morphological and histometric analyses in larvae revealed hypertrophic growth during the yolk sac stage. The expression of genes involved in muscle development and growth indicated no differences in growth potential in larvae between groups. Overall, broodstock feeds for gilthead seabream can have an inclusion of novel ingredients without a negative impact on larval performance and growth. Further studies are needed to study the long‐term effects of broodstock diet on offspring quality.