Chondral lesions caused by stressors, such as injury or inflammation, lead to osteoarthritis (OA). OA is a degenerative joint disease that has become a challenge worldwide. As the articular cartilage is incapable of self-regeneration due to the absence of vessels and nerves, novel cartilage repair techniques are urgently needed. Three-dimensional (3D) bioprinting, which allows the precise control of internal architecture and geometry of printed scaffolds, has stepped up to be a promising strategy in cartilage restoration. With regards to 3D bioprinting, bioinks with proper chemical and mechanical properties play one of the most critical roles in designing successful cartilage tissue constructs. In particular, hydrogels as 3D hydrophilic cross-linked polymer networks are highly recommended as bioinks because of their fine biocompatibility, easy fabrication, and tunable mechanical strength. Herein, we highlight the widely used polymers for hydrogel preparation and further provide a non-exhaustive overview of various functional modified additives (such as cells, drugs, bioactive factors and ceramic) to exploit the unique properties suitable for bioprinted cartilage. Finally, a prospective on future development for 3D-bioprinting in cartilage repair is elucidated in this review.

The roles of cells in systemic aging have been systematically investigated, while the roles of the extracellular matrix (ECM) and its degradation have been largely overlooked. Herein, we show that the serum contents of elastin-, hyaluronic acid- and fibronectin-derived fragments are all positively correlated with age. Elastin-derived fragments exhibited the most potent lifespan-shortening effects in mice and a positive correlation with various aging indicators in a human cohort (n = 1,068). Mechanistically, the VGVAPG oligopeptide (E-motif) in elastin-derived fragments activated monocytes and macrophages through NEU1, a component of the elastin receptor complex, which consequently caused an inflammatory response. Therapeutically, a NEU1 inhibitor extended lifespan by up to 17% in wild-type naturally aged mice and alleviated aging-related phenotypes in wild-type mice, immune-humanized mice and pigs. This study uncovers that degraded ECM acts as a circulating driver of aging, providing an anti-aging intervention strategy focused on particular elastin fragment signals.

The anterior cruciate ligament is anchored to the femur and tibia via specialized interfaces known as entheses. These play a critical role in ligament homeostasis and joint stability by transferring forces, varying in magnitude and direction between structurally and functionally dissimilar tissues. However, the precise structural and mechanical characteristics underlying the femoral and tibial entheses and their intricate interplay remain elusive. In this study, two thin-graduated mineralization regions in the femoral enthesis (~21 μm) and tibial enthesis (~14 μm) are identified, both exhibiting distinct biomolecular compositions and mineral assembly patterns. Notably, the femoral enthesis interface exhibits progressively maturing hydroxyapatites, whereas the mineral at the tibial enthesis interface region transitions from amorphous calcium phosphate to hydroxyapatites with increasing crystallinity. Proteomics results reveal that Matrix Gla protein uniquely enriched at the tibial enthesis interface, may stabilize amorphous calcium phosphate, while C-type lectin domain containing 11 A, enriched at the femoral enthesis interface, could facilitate the interface mineralization. Moreover, the finite element analysis indicates that the femoral enthesis model exhibited higher resistance to shearing, whereas the tibial enthesis model contributes to tensile resistance, suggesting that the discrepancy in biomolecular expression and the corresponding mineral assembly heterogeneities collectively contribute to the superior mechanical properties of both the femoral enthesis and tibial enthesis models. These findings provide novel perspectives on the structure-function relationships of anterior cruciate ligament entheses, paving the way for improved management of anterior cruciate ligament injury and regeneration.

Pre-eclampsia (PE), associated with placental malperfusion, is the primary reason for maternal and perinatal mortality and morbidity that can cause vascular endothelial injury and multi-organ injury. Despite considerable research efforts, no pharmaceutical has been shown to stop disease progression. If women precisely diagnosed with PE can achieve treatment at early gestation, the maternal and fetal outcomes can be maximally optimized by expectant management. Current diagnostic approaches applying maternal characteristics or biophysical markers, including blood test, urine analysis and biophysical profile, possess limitations in the precise diagnosis of PE. Biochemical factor research associated with PE development has generated ambitious diagnostic targets based on PE pathogenesis and dissecting molecular phenotypes. This review focuses on current developments in biochemical prediction of PE and the corresponding interventions to ameliorate disease progression, aiming to provide references for clinical diagnoses and treatments.

Although human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) have been used for disease modeling and drug discovery, clinically relevant three-dimensional (3D) functional myocardial microtissues are lacking. Here, we developed a novel ring-shaped cardiac microtissue comprised of chamber-specific tissues to achieve a geometrically non-orientable ventricular myocardial band, similar to a Möbius loop. The ring-shaped cardiac tissue was constructed of hiPSC-CMs and human cardiac fibroblasts (hCFs) through a facile cellular self-assembly approach. It exhibited basic anatomical structure, positive cardiac troponin T (cTnT) immunostaining, regular calcium transients, and cardiac-like mechanical strength. The cardiac rings can be self-assembled and scaled up into various sizes with outstanding stability, suggesting their potential for precise therapy, pathophysiological investigation, and large-scale drug screening. Graphic abstract

The construction of bone organoids represents a transformative approach in tissue engineering, offering unprecedented opportunities for studying bone biology, disease modeling, and regenerative medicine. The intricate understanding of the skeletal microenvironment, or niche, which governs cellular behavior, tissue organization, and functional maturation, is critical important to construct bone organoid. This review explored insights into the skeletal microenvironment, including the roles of extracellular matrix components, mechanical cues, biochemical signaling, and cellular interactions. It also proposes a foundational strategy how advancements in biomaterials, extracellular matrix, and micro-structure have enabled the precise recapitulation of niche conditions, facilitating the development of physiologically relevant bone organoids. Furthermore, we highlight the applications of these organoids in drug screening, personalized medicine, and bone regeneration. By bridging the gap between niche biology and organoid engineering, this review underscores the potential of microenvironment-driven approaches to revolutionize bone tissue engineering and its translational impact.