Search Results (292)

Background/Objectives: Degenerative processes of the hip joint increasingly affect not only the articular cartilage but also periarticular structures such as the joint capsule and acetabular labrum. This study aimed to investigate the structural and molecular changes occurring in these tissues during advanced hip osteoarthritis. Methods: A combined analysis using immunohistochemistry (IHC), scanning electron microscopy (SEM), and micro-computed tomography (microCT) was conducted on tissue samples from patients undergoing total hip arthroplasty and from controls with morphologically normal joints. Markers associated with proliferation (Ki67), inflammation (CD68), angiogenesis (CD31, ERG), chondrogenesis (SOX9), and lubrication (Lubricin) were evaluated. Results: The pathological group showed increased expression of Ki67, CD68, CD31, ERG, and SOX9, with a notable decrease in Lubricin. SEM analysis revealed ultrastructural disorganization, collagen fragmentation, and neovascular remodeling in degenerative samples. A significant correlation between structural damage and molecular expression was identified. Conclusions: These results suggest that joint capsule and acetabular labrum degeneration are interconnected and reflect a broader pathophysiological continuum, supporting the use of integrated IHC and SEM profiling for early detection and targeted intervention in hip joint disease. Full article

Cartilage degradation is a key feature of osteoarthritis (OA), a joint disease that significantly impacts the quality of life of the elderly population. While advanced age is recognized as one of the major risk factors for OA, the underlying mechanisms are not fully understood. Research involving cartilage from aged animals has improved our understanding of the changes associated with aging. However, studies with aged animals can be time-consuming and costly. In this study, we investigate the use of human sera from older donors as a stressor to induce aging-like changes in cultured human chondrocytes. First, we assess the expression levels of markers related to chondrogenesis, hypertrophy, fibrosis, and inflammation in human chondrocytes treated with sera from younger or older human donors. Next, we evaluate the regenerative potential of these sera-treated chondrocytes by stimulating them with the anabolic factor transforming growth factor (TGF)-β3. The results show that treatment with sera from older donors induced an aging-like phenotype in chondrocytes and impaired their ability to generate new cartilage. These findings provide insight into the role of systemic factors (serum) in cartilage aging and offer a novel in vitro model for studying age-related changes in chondrocytes. Full article

Antlers exhibit exceptionally rapid growth, representing a rare biological phenomenon among mammals. In addition to their scientific significance, antlers are widely used in traditional medicine, and their yield directly impacts the economic efficiency of the deer farming industry. However, antler yield varies substantially among individuals, and the molecular mechanisms underlying this variation remain poorly understood. This study aimed to elucidate the transcriptomic and post-transcriptional mechanisms underlying antler yield variation by comparing gene and miRNA expression profiles across four distinct antler tissue layers—dermis (D), reserve mesenchyme (RM), pre-cartilage (PC), and cartilage (C)—in sika deer with different yields. RNA-seq and miRNA-seq were performed, followed by differential expression, GO and KEGG pathway enrichment, and miRNA–mRNA co-expression network analyses. Our results reveal layer-specific expression patterns and key regulatory genes and miRNAs associated with proliferation, chondrogenesis, angiogenesis, and mineralization. In particular, genes such as FBP2, TPT1, TFRC, ZEB1, and PHOSPHO1 were upregulated in high-yield deer across specific tissue layers, while NFATC2 was downregulated in these high-yield deer. Additionally, miRNAs such as miR-140, miR-296-3p, and let-7e exhibited layer-specific expression patterns linked to growth and differentiation. Our miRNA–mRNA regulatory network analysis highlighted significant interactions, particularly miR-296-3p–PHOSPHO1 and miR-296-3p–FBP2, as key regulators of antler growth. Enrichment of PI3K-Akt and TGF-β signaling pathways further suggests their involvement in promoting chondrogenesis and ossification. These findings provide novel insights into the molecular basis of antler growth and yield, which may inform future strategies for selective breeding in deer farming. Full article

Mesenchymal stem cells (MSCs) represent a promising cell source for cartilage tissue engineering due to their chondrogenic potential. However, current differentiation protocols result in limited efficiency. This study assessed the combined effects of transforming growth factor-beta 3 (TGF-β3) and fibroblast growth factor-2 (FGF-2) on the morphology, proliferation, chondrogenic differentiation, chondrogenic gene expression, and cytokine profile of ovine bone marrow-derived MSCs (BM-MSCs). BM-MSCs were cultured under four conditions: control (αMEM) or αMEM supplemented with FGF-2, TGF-β3, or TGF-β3 + FGF-2. Morphological and proliferation analyses, Alcian blue staining in 2D and 3D, and real-time PCR for early (Chad, Comp, and Sox 5) and late (Agg, Col IX, Sox 9, and Fmod) chondrogenic markers were performed. Cytokine secretion profiles were analyzed using multiplex assay. TGF-β3 induced morphological changes indicative of early chondrogenesis, while FGF-2 enhanced proliferation. The combination of both cytokines led to a synergistic increase in cell proliferation, early and late chondrogenic gene expression, and glycosaminoglycans (GAG) deposition. Cytokine analysis revealed that TGF-β3 enhanced the immunomodulatory and angiogenic profile of BM-MSCs, whereas co-treatment with FGF-2 yielded a balanced and potentially regenerative secretome. Dual stimulation with TGF-β3 and FGF-2 significantly improves the chondrogenic differentiation of ovine BM-MSCs by enhancing both molecular and functional markers of cartilage formation. Full article

Due to the limited regeneration of cartilage, new implant materials are needed. Biodegradable polymers poly-(D,L)-lactide-ε-caprolactone-methacrylate (LCM) and polyamid-ε-caprolactone-methacrylate (ACM) were recently established and coated with heparin, making them able to prevent blood coagulation and cartilage mineralization. The aim of this study was to analyze the suitability of LCM and ACM alone or coated with heparin (the latter are abbreviated as LCMH and ACMH, respectively) as implant material for cartilage repair. Therefore, mesenchymal stem cells were chondrogenically differentiated in 2D cultures with polymer discs. Differentiation was induced by the supplementation of cell medium with dimethyloxalylglycine, TGF-β, and BMP2. After 5 days, no increase in proinflammatory factors was observed. Cell viability declined on ACM and ACMH discs. During early chondrogenesis, SOX9 expression increased on LCM and LCMH discs, while TRPV4 expression decreased on ACMH discs. At day 20, the level of collagen type II increased on LCM, LCMH, and ACM discs, demonstrating the ability of chondrogenic development on these implants. In summary, coating with heparin showed no advantages compared to pure LCM and ACM. For cartilage repair, LCM is more suitable than ACM in this 2D in vitro model, which needs to be verified by long-term 3D models and in vivo studies. Full article

Long-term solutions for cartilage repair after injury are currently being investigated, with most research aiming to exploit the regenerative and chondrogenic differentiation potential of stem-cell-based spheroids. The incorporation of the bioactive polymer CTL, a lactose-modified chitosan, into spheroids is a strategy to improve cell viability and accelerate type II collagen gene expression. In this work, the role of CTL in influencing the dynamics of spheroid formation and its interplay with cell membrane adhesion molecules (integrins and cadherins) and cytoskeletal components is elucidated. The results indicate that CTL is actively involved in the reorganization of cells into spheroids. An analysis of the effects of physical form of CTL (rehydrated polymer coating or polymer solution) in stimulating peculiar biological responses indicates that CTL matrix in spheroids facilitates an early phase of chondrogenic differentiation. Once the CTL matrix is included in spheroids, there is an increase in COL2A1 gene expression and matrix deposition, regardless of the initial physical form of CTL. Overall, these results contribute to a better understanding of the dynamics of spheroid formation in the presence of the polymer and on its bioactive role in mesenchymal stem cell spheroids. Full article

Primary osteoporosis in children and young adults often suggests a monogenic disease affecting bone microarchitecture and bone mineral density. While Osteogenesis Imperfecta (OI) is the most recognized genetic cause of recurrent fractures, many other genes involved in bone metabolism may contribute to osteoporosis. Among them, FGFR2 plays a critical role in bone growth and development by regulating osteoblast differentiation and proliferation, as well as chondrogenesis. Germline pathogenic FGFR2 variants are typically associated with syndromic craniosynostosis, conditions not characterized by bone fragility or osteoporosis. A report recently identified FGFR2 as a potential cause of dominant early-onset osteoporosis and bone fractures in a family. We report the case of a child affected by severe osteoporosis with multiple fractures. We performed clinical exome sequencing in trio to investigate potential genetic causes of the observed phenotype and identified a likely mosaic pathogenic FGFR2 variant, absent in both parental samples. Our findings provide further evidence that FGFR2 pathogenic variants can lead to a novel non-syndromic bone mineralization disorder, reinforcing the role of FGFR2 in the pathogenesis of early-onset osteoporosis. Full article

Although the roles of proteoglycans (PGs) have been well documented in the development and homeostasis of the temporomandibular joint (TMJ), how the glycosaminoglycan (GAG) chains of PGs contribute to TMJ chondrogenesis and osteogenesis still requires explication. In this study, we found that FAM20B, a hexokinase essential for attaching GAG chains to the core proteins of PGs, was robustly activated in the condylar mesenchyme during TMJ development. The inactivation of Fam20b in craniofacial neural crest cells (CNCCs) dramatically reduced the synthesis and accumulation of GAG chains rather than core proteins in the condylar cartilage, which resulted in a hypoplastic condylar cartilage by severely promoting chondrocyte hypertrophy and perichondral ossification. In the condyles of Wnt1-Cre;Fam20b^f/f mouse embryos, enlarged Ihh- and COL10-expressing domains indicated premature hypertrophy resulting from an attenuated IHH-PTHRP negative feedback in condylar chondrocytes, while increased osteogenic markers, canonical Wnt activity, and type-H angiogenesis verified the enhanced osteogenesis in the perichondrium. Further ex vivo investigations revealed that the loss of Fam20b decreased the domain area but increased the activity of HH signaling in the embryonic condylar mesenchyme. Moreover, the abrogation of GAG chains in heparan sulfate and chondroitin sulfate proteoglycans led to a rapid up- and then downregulation of HH signaling in condylar chondrocytes, implicating a “slow-release” manner of growth factors controlled by GAG chains. Overall, this study revealed a comprehensive role of the FAM20B-catalyzed GAG chain synthesis in the chondrogenic and osteogenic differentiation of the embryonic TMJ condyle. Full article

Dedifferentiated fat (DFAT) cells are adipocyte-derived cells that are able to differentiate into multiple cell lineages such as adipocytes, osteoblasts and chondrocytes, similar to mesenchymal stem cells (MSCs). Despite their great potential for developing novel clinical interventions by using their multipotency, the detailed mechanisms of how adipocytes undergo dedifferentiation into DFAT cells are not completely understood, because useful in vitro tools for studying adipocyte dedifferentiation are missing. In this study, we show that mature adipocytes derived from the MSC cell line C3H10T1/2 underwent dedifferentiation into cells with DFAT cell-like characteristics, when they were cultured in an inverted flask. During the dedifferentiation, expression levels of genes and protein specific to adipocytes were continuously decreased, whereas those for MSC, proliferation and WNT/β-catenin signaling were gradually increased. These DFAT-like cells also underwent differentiation into adipocytes, osteoblasts and chondrocytes with their specific cell morphology and gene expression. We also observed that an individually cultured single adipocyte also underwent dedifferentiation into DFAT-like cells that were able to differentiate into the multiple cell lineages. Our results indicate that C3H10T1/2 cells could be a great tool for determining molecular biological and biochemical mechanisms underlying adipocyte dedifferentiation. Full article

Bone diseases represent a growing healthcare challenge due to population aging and lifestyle changes. Although bone has a natural regenerative capacity, approximately 10% of fractures fail to heal properly, requiring advanced therapeutic approaches. Bone tissue engineering (BTE) has advanced the use of osteoinductive and osteoconductive biomaterials to support bone regeneration. Among them, Bio-Oss^® Collagen, a composite of bovine hydroxyapatite and collagen, has shown excellent biocompatibility and bioactivity properties. This study analyzes the effect of Bio-Oss^® Collagen on human bone marrow-derived mesenchymal stem cells (hBMSCs), assessing its osteoinductive and immunomodulatory potential. After 7 days of culture, the biomaterial modulated the expression of key genes involved in osteogenesis and chondrogenesis, which are known for their role in bone formation and maturation. At the same time, a downregulation of genes associated with bone resorption was observed. Secretome analysis revealed a controlled release of pro-regenerative cytokines, suggesting a role of the biomaterial in modulating inflammation to promote bone regeneration. Furthermore, immunofluorescence confirmed the high expression of osteocalcin and osteopontin, which are key markers of bone mineralization. These findings indicate that Bio-Oss^® Collagen supports osteogenesis and modulates the immune response, creating a microenvironment favorable for bone regeneration. Full article

Background/Objectives: The treatment of cartilage damage is an ongoing challenge. Several techniques have been developed to address this problem. Matrix-Induced Autologous Chondrocyte Implantation (MACI) is often referred to as the “gold standard” for cartilage treatment. Numerous long-term outcome studies also have reported favorable results with Autologous Matrix-Induced Chondrogenesis (AMIC). Minced Cartilage Implantation (MCI) is a recently developed arthroscopic method. This technique has demonstrated promising outcomes, with the prospect of longer-term results still under investigation. This study aims to directly compare the patient-reported outcomes of these three techniques over a 2-year follow-up period. Methods: A total of N = 48 patients were included in the retrospective matched pair analysis (n = 16 MACI, n = 16 AMIC, n = 16 MCI). VAS, KOOS-Pain, and KOOS-Symptoms scores served as primary outcomes; the KOOS-ADL and -QOL and the Tegner Activity Scale (TAS) served as secondary outcomes. Results: All three groups did not differ from each other in the primary or secondary outcomes. Pain and function significantly improved from pre-surgery to two years after (VAS: p < 0.000; ES: η² = 0.27; KOOS-Pain: p < 0.000; ES: η² = 0.30; KOOS-Symptoms: p = 0.000; ES: η² = 0.26; KOOS-ADL: p > 0.000; ES: η² = 0.20; KOOS-QOL: p > 0.000; ES: η² = 0.30). There was no significant effect of time on the activity level. Conclusions: All three procedures show good patient-reported outcomes, low complication rates, and long graft longevity in the 2-year follow-up. Therefore, all three methods seem to be equally recommendable for the treatment of cartilage lesions. Full article

Background: Oral cancer is an aggressive malignancy with modest survival rates. It also causes disfigurement following surgical removal of the tumor, thus highlighting the need for new cancer treatment and tissue repair modalities. Carbon-based nanomaterials have emerged as promising tools in both anticancer and regenerative therapies. Objectives: We aimed to synthesize a new carbon-based nanomaterial (CBN) and test its antineoplastic effects, as well as its potential regenerative capacity. Materials and Methods: A carbon nanomaterial, obtained by ball milling graphite flakes, was functionalized with polyvinylpyrrolidone (CBN/PVP). Its physicochemical properties were explored with X-ray diffraction (XRD), attenuated total reflection–Fourier transform infrared spectroscopy (ATR-FTIR), micro-Raman spectroscopy, fluorescent and scanning electron microscopy, and wettability analysis. For the antineoplastic effects investigation, oral cancer cells were treated with CBN/PVP and examined with MTT and migration assays, as well as cell-cycle and ROS production analyses. Gene expression was determined by qPCR. To examine the pro-regenerative capacity of CBN/PVP, dental pulp stem cell cultures (DPSCs) were treated with the nanomaterial and subjected to osteo- and chondro-induction. Results: Lower concentrations of CBN/PVP (50, 100 μg/mL) applied on cancer cells exerted remarkable cytotoxic effects, induced G1 cell-cycle arrest, and reduced cancer cell invasion potential by different mechanisms, including downregulation of the PI3K/AKT/mTOR pathway. In contrast, the addition of 50 µg/mL of CBN/PVP to DPSCs stimulated their survival and proliferation. CBN/PVP significantly enhanced both the osteogenic (p < 0.05) and chondrogenic (p < 0.01) induction of DPSCs. Conclusions: The novel carbon-based nanomaterial displays unique characteristics, making it suitable in anticancer and regenerative therapies concomitantly. Full article

Mesenchymal stem cells (MSCs) can differentiate into chondrocytes provided with the appropriate environmental cues. In this study, we loaded human adipose-derived stem cells (hAdMSCs) into collagen/alginate hydrogels, which have been shown to induce chondrogenesis in ovine bone marrow stem cells without the use of any exogenous chondrogenic growth factors. We examined the influence of hydrogel stiffness (5.75 and 6.85 kPa) and cell seeding density (1, 2, 4, and 16 × 10⁶ cells/mL) on the chondrogenic induction of hAdMSCs, without exogenous differentiation growth factors. Over time, the behaviour of the hAdMSCs in the scaffolds was investigated by analysing the amount of DNA; their morphology; their cell viability; the expression of chondrogenic genes (RT-qPCR); and the deposition of collagen I, collagen II, and aggrecan. The results showed that all scaffolds supported the acquisition of a rounded morphology and the formation of cell aggregates, which were larger with higher cell seeding densities. Furthermore, the cells were viable within the hydrogels throughout the experiment, indicating that high cell density did not have a detrimental effect on viability. All the conditions supported the upregulation of chondrogenic genes (SOX9, COL2A1, SOX5, and ACAN). By comparison, only the highest cell seeding density (16 × 10⁶ cells/mL) promoted a superior extracellular matrix deposition composed of collagen II and aggrecan with limited production of collagen I. These molecules were deposited in the pericellular space. Furthermore, no histological difference was noted between the two stiffnesses. Full article

The mandibular condyle cartilage serves as a principal zone for mandible growth, and any dysplasia could contribute to skeletal mandibular hypoplasia (SMH). The aim of the study was to further explore how TFRC signaling regulates condylar cartilage development. In this study, TFRC, SLC39A14, chondrogenic markers and ferroptosis-related signals were detected in the condylar cartilage of postnatal mice and Tfrc cartilage conditional knockout (Tfrc-cKO) mice at different time points through immunofluorescence, immunohistochemical staining and qPCR assays. The overexpression and knockdown of TFRC in the ATDC5 cell line were used to investigate its role in a specific biological process. Co-immunoprecipitation was used to verify protein–protein interaction in vitro. Ferroptosis inhibitor Fer1, Ac-Met-OH and DFP were used for an in vitro rescue assay. The temporomandibular joint injection of DFP was used to rescue the cartilage phenotype in vivo. Our results verified that TFRC was crucial for condylar cartilage development. TFRC ablation led to condylar cartilage thickness and condyle length alterations and induced the ferroptosis of chondrocyte by upregulating SLC39A14. Mitochondrial p53 translocation was involved in the TFRC–SLC39A14 switch by SLC39A14 ubiquitination degradation. Fer1, Ac-Met-OH and DFP inhibited ferroptosis and restored chondrogenic differentiation in vivo. The temporomandibular joint injection of DFP could rescue the cartilage phenotype. In summary, this study reveals that TFRC influences postnatal condylar cartilage development through mitochondrial p53 translocation-mediated ferroptosis, which provides insights into the etiology, pathogenesis, and therapy of mandibular hypoplasia and even systemic articular cartilage dysplasia. Full article

Background: Transforming growth factor-β (TGF-β) and interleukin 1β (IL-1β) are key regulators of the chondrogenic differentiation, physiology and pathology of cartilage tissue, with TGF-β promoting chondrogenesis and matrix formation, while IL-1β exerts catabolic effects, inhibiting chondrogenesis and contributing to cartilage degradation. Both cytokines alter the intracellular calcium ion (iCa²⁺) levels; however, the exact pathways are not known. Objectives: This study aimed to evaluate the impact of TGF-β3 and IL-1β on calcium homeostasis in human bone marrow-derived mesenchymal stem cells (hBM-MSCs) and chondrocytes during chondrogenesis. Results: TGF-β3 increased iCa²⁺ levels in both hBM-MSCs and chondrocytes. Furthermore, TGF-β3 increased the functional activity of L-type voltage-operated calcium channels (L-VOCCs) in hBM-MSCs but not in chondrocytes. TGF-β3 and IL-1β reduced L-VOCCs subunit CaV1.2 (CACNA1C) gene expression in chondrocytes. In hBM-MSCs, TGF-β3 and IL-1β increased SERCA pump (ATP2A2) gene expression, while in chondrocytes, this effect was observed only with TGF-β3. Conclusions: TGF-β3 increases iCa²⁺ both in osteoarthritic chondrocytes and hBM-MSCs during chondrogenesis. In hBM-MSCs, TGF-β3-mediated elevation in iCa²⁺ is related to the increased functional activity of L-VOCCs. IL-1β does not change iCa²⁺ in osteoarthritic chondrocytes and hBM-MSCs; however, it initiates the mechanisms leading to further downregulation of iCa²⁺ in both types of cells. The differential and cell-specific roles of TGF-β3 and IL-1β in the calcium homeostasis of osteoarthritic chondrocytes and hBM-MSCs during chondrogenesis may provide a new insight into future strategies for cartilage repair and osteoarthritis treatment. Full article