Connective Tissue Research最新文献

Purpose/aim: Bone regeneration and repair are critical research areas within regenerative medicine, aiming to address the challenges posed by critical-sized bone defects. Bioscaffolds and cell-based therapies have been explored to enhance osteogenesis and promote effective bone regeneration. This study aimed to assess the regenerative potential of rabbit amniotic membrane (rAM) derived bioscaffold and its comparative evaluation with another bioscaffold, the decellularized periosteum (DP) of the buffalo rib, which was recellularized with rAM derived mesenchymal stem cells (MSCs).

Materials and methods: Passage 3 (P3) rAM-MSCs were validated for positive and negative stemness marker expression by PCR, immunolocalization and trilineage differentiation. Fresh rAM was cryopreserved for three months. An autologous rabbit model was used to assess the osteogenic capacity of different bioscaffolds: fresh rAM (Group II), frozen-thawed rAM (Group III), DP (Group IV), and DP enriched with rAM-MSCs (Group V) and control (Group I) in critical-size defect of 10 mm in radius bone. Radiographic evaluation was performed on the 1^st, 60^th and 90^th days, and ultramicroscopic and histomorphological evaluations were performed.

Results: Groups II and V presented the highest levels of remodeling and osteogenesis, a reduction in the defect size and total radiological scores. Groups II and V had the highest levels of osteogenesis, bone marrow development, cortical bone production, and medullary bone formation and the highest total histology score.

Conclusions: These findings revealed that fresh rAM, a rich source of MSCs, and DP enhanced with rAM-MSCs are the preferred bioscaffolds for critical-sized bone defect repair.

Purpose/aim: Osteoarthritis is a common cause of disability worldwide. Exosomes are extracellular vesicles and can exert paracrine and endocrine actions. DPSCs exosomes offer a new avenue of research that may elucidate various functions related to cell proliferation, differentiation, and immunomodulation. We hypothesized that DPSC exosomes produced under hypoxia-induced culture conditions may have an anti-inflammatory effect on osteoarthritic chondrocytes and may re-regulate the inflammatory response that is increased in osteoarthritis. We also hypothesized that the decreased glycosaminoglycan production in osteoarthritis may be re-induced by DPSC exosomes produced under hypoxia.

Materials and methods: Exosomes were isolated from DPSCs under hypoxic (3% O₂) and normoxic conditions (21% O₂) separately and were applied to OA chondrocyte cells. Quantification, morphology and analysis of tetraspanin markers were performed to characterize the exosomes. After the OA chondrocytes were treated with exosomes for 48 hours, they were prepared for cell proliferation, apoptosis, viability, glycosaminoglycan tests, and inflammatory cytokine analysis.

Results: Our results show that the pro-inflammatory cytokines were significantly suppressed in osteoarthritic chondrocytes by DPSC exosomes produced under hypoxia (p < 0.05). Exosomes of DPSCs grown in a hypoxia environment dramatically increase the amount of GAG in OA chondrocytes, giving clues that they can be used in cartilage regeneration (p < 0.001).

Conclusions: Considering that OA is associated with inflammatory components, DPSC exosome produced under hypoxic conditions prevents the formation of proinflammatory cytokines in osteoarthritic chondrocytes and shows therapeutic effects on osteoarthritic chondrocytes. Our study provides the first evidence showing the efficacy of DPSC-derived exosomes produced under hypoxia on osteoarthritic chondrocytes.

Purpose/aim: Temsirolimus is a water-soluble mammalian target of rapamycin (mTOR) complex inhibitor, potentially suitable for intra-articular administration. The present study aims to evaluate the therapeutic effects of intra-articular administration of temsirolimus on human chondrocytes and osteoarthritis (OA) progression in mice.

Materials and methods: The beneficial effects of temsirolimus treatment were evaluated in human chondrocytes (Normal Human Articular Chondrocyte-Knee cells) with or without treatment with IL-1β in vitro by real-time polymerase chain reaction, TUNEL staining for apoptosis, and CYTO-ID(R) staining for autophagy. The therapeutic effect of intra-articular injection of temsirolimus was evaluated in OA models (destabilized medial meniscus in C57BL/6J and senescence accelerated mice prone 8 (SAMP8)) in vivo, by histological and immunohistochemical analyses.

Results: Temsirolimus treatment upregulated COL2A1 and aggrecan (a major proteoglycan in the articular cartilage) expression in human chondrocytes. In addition, temsirolimus treatment recovered IL-1β-induced down-reregulated COL2A1 and aggrecan expression, while it partially decreased upregulated MMP-1, MMP-13, ADAMTS-4, ADAMTS-5, IL-1β, and IL-6 expression and apoptosis in human chondrocytes. Further, temsirolimus treatment enhanced autophagic activity in human chondrocytes. The intra-articular injection of temsirolimus to 12-week and 1-year old wild-type surgically induced OA model mice and SAMP8 mice delayed OA progression as compared to that in the control mice.

Conclusions: Temsirolimus treatment protected human chondrocytes from IL-1β-induced OA gene expression changes and apoptosis. Intra-articular injection of temsirolimus delayed OA progression in the mouse OA model and in SAMP8 mice. Thus, the intra-articular administration of temsirolimus is a promising therapeutic approach to inhibit articular cartilage degradation.

Purpose/aim: Dupuytren's disease (DD) is a condition affecting the palmar fascia that may reduce the mobility of several fingers. Despite its clinical relevance, the genetic and structural mechanisms associated with this disease are still not well understood. In this work, we have carried out a genome-wide gene expression analysis to identify relevant genes associated with DD.

Materials and methods: A genome-wide gene expression analysis was carried out using next generation sequencing (NGS) followed by a histological, histochemical and immunohistochemical analysis of some major components of the palmar fascia in 26 DD patients and 17 control subjects without the disease (CTR).

Results: We found 237 genes or sequences differentially expressed between DD and CTR, with those genes corresponding to several gene pathways and functions related to contractility, development and morphogenesis, differentiation, extracellular matrix (ECM), migration and ossification. In turn, the histological analysis confirmed that DD tissues showed a disorganized ECM, with nonaligned fibers, and abundant cells were found scattered along the whole tissue. CTR showed significantly higher amounts of proteoglycans revealed by alcian blue, along with versican, keratan-sulfate, myoglobin, tropomyosin 3, filamin C and titin, whereas DD showed significantly enriched in collagen fibers, especially collagens type-I and V, MMP-14, S-100, tubulin-beta, SMA and tenascin C, with disorganization of the elastic fibers.

Conclusions: In general, these results confirm that a significant alteration of the tissue organization, extracellular matrix and structure is related to DD. These results could contribute to the future development of diagnostic and treatment strategies for this disease.

Osteoarthritis (OA) is a progressive joint disorder that leads to pain and disability for millions of people worldwide. Post-traumatic OA (PTOA), a form of OA, arises secondary to joint injury and often impacts younger individuals. Among the most common joint injuries leading to disrupted joint homeostasis and PTOA is anterior cruciate ligament (ACL) rupture. Even with successful surgical stabilization, the risk of developing PTOA persists due to several factors, including altered biology that contributes to disease progression. Recent research into the biology of ACL injuries has advanced our understanding of the mechanisms by which PTOA develops, including the inflammatory pathways involved, the expression of biomarkers specific to ACL injuries, and their interaction with factors such as the chronicity of the injury. Evidence suggests that homeostatic balance of anabolic and catabolic processes in the knee is disturbed after ACL tears, triggering a catabolic and degenerative phenotype, ultimately leading to premature joint degeneration, pain, and disability. Several key knowledge gaps exist, such as the determinants of the transition from acute to chronic inflammation, inter-patient variability in inflammatory responses, and influence of systemic factors on disease development. PTOA research faces numerous challenges, including protracted nature of the disease, the complexity of joint biology, and difficulties in translating molecular discoveries into clinical practice. Future research should prioritize improving biomarker precision for early detection, developing targeted therapies, and leveraging emerging technologies like machine learning to personalize treatment. This approach will enhance our understanding of the biological basis of PTOA resulting from ACL injuries and identify opportunities to mitigate the long-term consequences of these injuries.

Knee osteoarthritis (OA) is a debilitating condition with limited treatment options beyond symptom management or total knee arthroplasty (TKA). For younger patients, TKA presents challenges, including higher failure rates and revision surgeries. Knee joint distraction (KJD) has emerged as a promising joint-preserving alternative for end-stage knee OA, demonstrating significant improvements in pain, function, and quality of life in clinical trials and clinical practice. Almost 20 years of research has highlighted KJD's capacity to delay or prevent TKA by promoting cartilage and subchondral bone repair through whole-joint remodeling. Recent studies, including a multicenter trial with a purpose-built distraction device, confirm the treatment's efficacy and durability, with benefits lasting up to 10 years. However, long-term outcomes remain limited, and variability in patient response underscores the need for refined predictive tools. Challenges include the high incidence of pin tract infections during treatment and integrating KJD into routine clinical practice, as highlighted by limited trial enrollment in the UK KARDS trial and variability in healthcare system compatibility. Future research should focus on minimizing complications, improving patient selection through advanced imaging and biomarker analyses, and further understanding the mechanisms underlying KJD-induced joint remodeling. Large-scale trials like the ongoing Dutch GODIVA study are poised to provide robust evidence for KJD's broader adoption, implementation, and reimbursement in healthcare systems. With continued advancements, KJD holds the potential to transform the management of knee OA, offering a viable alternative to TKA for younger patients and addressing a critical unmet need in OA care.

Osteoarthritis (OA) is a chronic degenerative disease of the joint, involving cartilage degradation, synovial inflammation, and subchondral bone remodeling. Extracellular vesicles (EVs)-membrane-bound particles released by cells and have emerged as key mediators of intercellular communication in joint homeostasis and OA pathogenesis. EVs facilitate crosstalk between chondrocytes, synovial fibroblasts, and mesenchymal stem cells (MSCs), influencing joint health and disease progression. In OA, EV cargo: including proteins, miRNAs, and lipids, undergoes pathological changes that promote inflammation, matrix degradation, senescence, and calcification. Recent studies demonstrate that OA-derived EVs can induce catabolic and pro-inflammatory responses in recipient cells, while EVs from therapeutic sources such as MSCs, exhibit chondroprotective and anti-inflammatory effects in preclinical models. Additionally, EV surface markers and cargo profiles correlate with OA severity and pain, supporting their utility as minimally invasive biomarkers for early diagnosis and patient stratification. Cross-species comparisons suggest that EV signatures may be conserved, highlighting their translational potential in both human and veterinary medicine. However, the field is limited by variability in EV isolation and characterization methods, which hampers reproducibility and clinical application. To advance the clinical translation of EVs, standardized workflows and a deeper mechanistic understanding of EV function in the joint are essential. Identifying disease-specific EV biomarkers could enable earlier OA diagnosis and personalized treatment strategies, while optimizing therapeutic EVs could support regenerative approaches to slow or reverse joint degeneration and improve outcomes for human patients.

Aging is the largest risk factor for the development of osteoarthritis (OA), a major contributor to increased years lived with disability. This review reflects on how age-related changes relevant to OA have been measured at various length scales. Key discoveries include increased chondrocyte DNA damage with age and the disruption of matrix homeostasis by cellular senescence. Epigenetic clocks have yet to show predictive value for OA, while transcriptomic changes and miRNA profiles are linked to aging and senescence. Protein biomarkers have gained traction in the context of post-traumatic OA and may also be useful in understanding risk profiles for age-related OA. Post-translational modifications provide insights into protein aging and the rate of matrix turnover at different joint sites. Non-enzymatic crosslinks also increase with age and may be responsible for changes to the mechanical properties of joint tissues. Finally, the walking speed declines with age and predicts incident OA. Despite these advances, more research is needed on age-related changes in tissues beyond cartilage. Efforts should be directed toward identifying biomarkers of aging that can integrate large studies on genetic risk factors with the deep phenotyping done in longitudinal cohort OA studies. Early intervention is crucial for treating OA and other age-related diseases, highlighting the importance of validating sensitive and predictive biomarkers that could support new treatment paradigms. Finally, reversing at least some aspects of age-related decline may be critical for improving joint function. Promising approaches include effective delivery of targeted senolytics and the use of partial reprogramming to rejuvenate chondrocytes.

Osteoarthritis (OA) remains a major challenge for clinicians and researchers, as current treatments predominantly focus on symptomatic relief without completely addressing the underlying pathogenesis. In this regard, intraarticular injections of mesenchymal stem cells (MSCs) are emerging as a promising choice to mitigate pain and functional impairment in knee OA patients. The strong optimism for this therapeutic modality is based on experimental evidence supporting a role for MSCs in modulating inflammation, as well as encouraging clinical trials reporting safety and significant pain mitigation outcomes. However, inconsistencies related to their therapeutic efficacy remain a key concern. Therefore, a comprehensive understanding of the mechanisms by which MSCs exert their anti-inflammatory and joint-preserving effects is critically needed to ensure wider clinical translation. Recent research underscores the significance of MSCs as biomedicines with the potential to modulate the pro-inflammatory pathobiology of the entire OA joint. Their ability to crosstalk with joint resident cells and the infiltrating immune cells to reduce the overall catabolic load on the OA joints is being recognized as a primary mechanism underlying their therapeutic benefits. In this review, we discuss the significance of intraarticular MSC injections in the field of OA clinical research and focus on the immunomodulatory mechanisms underlying the ability of MSCs to modulate inflammation within OA joints by targeting both immune and resident joint cells. We identify current limitations and highlight the need for multidisciplinary clinical and basic science research to establish innovative approaches to further develop MSC-based therapies as efficacious biomedicines to treat OA patients.