Osteoarthritis and Cartilage

Osteoarthritis (OA) drug development remains constrained by preclinical models that fail to recapitulate the multicellular interactions that regulate human joint inflammation and extracellular matrix degeneration in response to investigational drugs. Tanezumab, a humanized anti-nerve growth factor monoclonal antibody developed for non-opioid pain relief, advanced to late-stage clinical trials but was discontinued due to unresolved joint-localized safety concerns, including rapidly progressive OA. This study evaluated whether a human microfluidic joint-on-a-chip co-culture system could detect early biomarker responses to tanezumab exposure that were not apparent in conventional chondrocyte monoculture. Tanezumab was first tested in human chondrocyte monoculture under untreated and disease-like (i.e., IL-1{beta}-treated) conditions. Across a 20-analyte panel of inflammatory and matrix-remodeling biomarkers, statistically significant monoculture responses to tanezumab were limited to decreased IL-1{beta} from 335 to 132 pg/mL ([~]0.39-fold) and increased IL-8 from 575 to 675 pg/mL ([~]1.17-fold). Major OA-associated matrix-remodeling markers, including MMP-1, MMP-3, and MMP-13, remained largely unchanged, indicating that monoculture conditions are insufficiently sensitive to detect clinically predictive drug-related molecular changes. Tanezumab was then evaluated in co-cultures containing chondrocytes, osteoblasts, fibroblast-like cells, and macrophages under low-inflammation (i.e., M0 macrophage-based) and high-inflammation (i.e., M1 macrophage-based) conditions. In the M0-based co-culture, tanezumab increased MMP-1 from [~]4.20 x 104 to [~]6.20 x 104 pg/mL ([~]1.48-fold), MMP-3 from [~]8.00 x 104 to [~]1.20 x 105 pg/mL ([~]1.50-fold), and MCP-1 from 2.85 x 103 to 4.31 x 103 pg/mL ([~]1.51-fold). In contrast, the M1-based co-culture showed decreases in MMP-13 from [~]1.66 x 104 to [~]1.17 x 104 pg/mL ([~]0.70-fold) and IFN-{gamma} from [~]1.95 x 104 to [~]1.56 x 104 pg/mL ([~]0.80-fold), changes that may appear beneficial despite the drugs known clinical risks. Collectively, these findings show that low-inflammation multicellular co-culture revealed coordinated matrix remodeling and inflammatory responses to NGF blockade that were missed in monoculture and were partly obscured in highly stimulated disease-like conditions. This platform may provide a useful, human-relevant approach for safety signal assessment and early evaluation of OA therapeutics within a defined context of use focused on joint-specific, tissue-level drug-response testing.

Osteoarthritis (OA), a degenerative joint disease, is associated with increased systemic inflammation, chronic pain, and cardiovascular dysfunction. Epidemiological evidence establishes that OA increases the risk of cardiovascular disease (CVD) threefold, yet the causal role of OAs contributions remains underexamined. We assessed cardiac function longitudinally following destabilization of the medial meniscus (DMM) surgery to induce osteoarthritis in mice. DMM-mice exhibited significant, sexually dimorphic alterations in echocardiographic parameters. Female DMM mice developed impaired relaxation with altered E/A ratios, increased E/e ratios, and prolonged intraventricular relaxation time with no change in ejection fraction, while male DMM mice showed progressive systolic dysfunction with decreasing ejection fraction, increased E/e ratio, and prolonged intraventricular contraction time. Transcriptomic profiles and biochemical analyses demonstrated divergent cellular responses involving fibrosis and oxidative stress in female mice, whereas autophagic and apoptotic responses were observed in male mice. Using a tumor necrosis factor 2 (TNFR2) agonist shown to reduce systemic inflammation, we investigated its potential therapeutic role in the context of OA-induced cardiovascular dysfunction. TNFR2 agonism proved to be effective both prophylactically and therapeutically for female diastolic dysfunction. While prophylactic and therapeutic administration delayed male systolic dysfunction, the efficacy declined over time. Our findings demonstrate evidence of a novel sexually dimorphic model of OA-induced CVD that recapitulates the sexually dimorphic pattern of patient phenotypes and a promising new therapeutic approach to CVD. Translational RelevanceOsteoarthritis patients have higher, often unrecognized, cardiovascular risk, yet preclinical models linking joint disease to cardiac dysfunction remain unexplored. Using a murine preclinical model of OA reveals the key findings. First, OA alone drives sex-specific cardiac phenotypes - females develop diastolic dysfunction, whereas males develop progressive systolic impairment. Second, selective TNFR2 agonism prevents and reverses OA-induced diastolic dysfunction in female mice and delays systolic decline in males. These findings suggest sex-dependent cardiac monitoring in OA patients and indicate that TNFR2-targeted therapy will likely be a sex-informed intervention to provide cardioprotective benefit. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=131 SRC="FIGDIR/small/736778v1_ufig1.gif" ALT="Figure 1"> View larger version (43K): org.highwire.dtl.DTLVardef@1f41661org.highwire.dtl.DTLVardef@1e94cb7org.highwire.dtl.DTLVardef@1abbac0org.highwire.dtl.DTLVardef@171cc86_HPS_FORMAT_FIGEXP M_FIG C_FIG

BackgroundOsteoarthritis cartilage contains heterogeneous chondrocyte states, but molecular programs linked to state transitions within human cartilage remain incompletely resolved using public single-cell data. MethodsA retrospective reanalysis was conducted of a public human knee cartilage single-cell RNA sequencing dataset (GSE255460) including 8 osteoarthritis donors and 3 non-osteoarthritis donors (19 samples). Cells underwent sample-wise quality control and doublet removal, followed by batch-corrected clustering, chondrocyte subclustering with marker-based annotation, and trajectory inference using Slingshot. Regulatory chondrocytes were prioritized for osteoarthritis versus control differential expression, with downstream Gene Ontology/KEGG enrichment (Benjamini-Hochberg false discovery rate <0.05) and protein-protein interaction network hub screening. ResultsAfter quality control, 27,036 cells were retained. Chondrocytes formed multiple transcriptional states with branching-like continuous relationships, and regulatory chondrocytes localized near the main manifold and adjacent to multiple inferred branches, consistent with a transition-adjacent state. In regulatory chondrocytes, osteoarthritis versus control differential expression was enriched for collagen-containing extracellular matrix and extracellular matrix organization, endoplasmic reticulum lumen-associated secretory/proteostasis processes, cell-matrix adhesion (including focal adhesion), and transforming growth factor beta/SMAD-related signaling. Protein-protein interaction analysis of regulatory-chondrocyte differential genes identified five high-connectivity hub genes: COL5A1, COL5A2, COL6A1, COL1A2, and COL3A1. ConclusionThis public-dataset reanalysis supports a transition-adjacent regulatory chondrocyte program in osteoarthritis characterized by coordinated extracellular matrix remodeling with concurrent secretory/proteostasis and adhesion-transforming growth factor beta signatures, nominating collagen-network hubs as candidates for downstream validation.

Objectives: To investigate the biological and clinical relevance of knee alignment in osteoarthritis by integrating population-scale imaging, genome-wide association, and functional genetic analyses. Methods: Femorotibial angle was derived from dual-energy X-ray absorptiometry scans in UK Biobank using machine-learning methods. Associations with knee and hip osteoarthritis outcomes were assessed. A genome-wide association study of mean femorotibial angle was performed, followed by fine-mapping and pathway enrichment analyses. Mendelian randomization was used to explore potential causal relationships. Results: Varus alignment was strongly and progressively associated with knee pain, knee osteoarthritis, and total knee replacement (HR 3.42 [95% CI 2.92, 4.02]), with no association observed for hip osteoarthritis. GWAS identified 20 independent loci associated with femorotibial angle, enriched for pathways related to skeletal development, cartilage biology, and endochondral ossification. Post-GWAS analyses demonstrated regulatory effects across fetal and adult joint tissues, supporting life course influences on alignment. Genetic correlation analyses showed shared architecture between femorotibial angle and knee osteoarthritis. Causal analyses suggested that genetic liability to osteoarthritis reduces femorotibial angle ({beta} -0.11 [-0.16, -0.06]), while evidence for an overall causal effect of femorotibial angle on osteoarthritis risk was limited (OR 0.93 [0.79, 1.10]). Conclusions: Knee alignment and susceptibility to knee osteoarthritis are partially genetically determined. At the population level, these genetic determinants support a causal effect of osteoarthritis on knee alignment, whereas evidence for a causal effect of alignment on knee osteoarthritis was limited. Furthermore, this study identifies novel genetic loci linking knee alignment with pathways involved in skeletal development and cartilage biology relevant to osteoarthritis.

The surface layer of articular cartilage provides for low-friction joint movement and protects the tissue from mechanical wear. The superficial zone chondrocytes (SZCs) of the surface layer produce proteoglycan-4 (PRG4), which is a lubricant that is necessary to reduce friction. Articular cartilage has limited capacity for self-repair and cell-based therapies, such as autologous chondrocyte implantation (ACI), is used to stimulate repair. However, in ACI, cells are expanded on tissue culture polystyrene where SZC poorly attach, proliferate slowly and dedifferentiate. Consequently, expanded SZC produce fibrocartilage tissue with insufficient PRG4. We previously demonstrated that culturing SZC on chondrocyte-derived decellularized extracellular matrix (CM) enhances SZC attachment and preserves phenotype. Since fibronectin (FN) was identified as the most abundant matrix protein within CM, here we tested the hypothesis that FN-coated culture surfaces would partially reproduce the beneficial effects of CM. We found that, similar to CM, SZC on FN-coated polystyrene increased SZC attachment and proliferation. However, unlike CM, SZCs expanded on FN-coated polystyrene remained more dedifferentiated as indicated by spread cells, elevated fibroblastic and contractile mRNA levels, and increased formation of SMA positive stress fibers. Consistent with the dedifferentiated phenotype, SZC on FN-coated polystyrene displayed extensive stress fibers, and higher nuclear myocardin-related-transcription-factor-a (MRTF-A). In contrast, CM reduced stress fiber formation and diminished nuclear MRTF-A in SZC. CM provides matrix cues beyond FN that suppress dedifferentiation and preserve the SZC phenotype. Identifying the matrix cues necessary to improve SZC expansion could lead to the generation of a superior surface in ACI repair tissue.

Objective We developed a patient- and joint-specific explant co-culture system to model active psoriatic arthritis (PsA) and capture donor-specific tissue responses to therapeutic interventions. Methods Based on convergent joint pathology between end-stage osteoarthritis (OA) and PsA, OA cartilage-bone and synovium tissues from arthroplasty patients were exposed to synovial fluid (SF) obtained from PsA and OA patients. Histological outcomes (synovitis, proteoglycan distribution), curated gene expression, soluble mediators, and proteinase activity were assessed over 7-21-days. Model responses to dexamethasone (DEX) and the anti-tumor necrosis factor antibody adalimumab (ADA) were evaluated. Results PsA SF induced distinct inflammatory and tissue remodeling responses compared to OA SF and control conditions, including altered cartilage proteoglycan distribution, increased synovitis, and tissue-specific transcriptional changes. Multivariate analyses identified distinct osteochondral and synovial transcriptional responses to PsA SF, characterized by reduced osteochondral COL2A1 expression and increased synovial expression of inflammatory and matrix-remodeling genes, including MMP1 and CXCL8. DEX and ADA elicited donor-specific responses across histological, transcriptional, and protein readouts. Among multivariable model outputs, histologic synovitis scores emerged as the most clinically aligned parameter, demonstrating associations with baseline PsA donor disease activity, active joint counts, pain, high-sensitivity C-reactive protein (hsCRP), and radiographic scores. Synovitis score changes to DEX and ADA treatments also aligned with corresponding PsA SF donor clinical improvements to corticosteroid and TNF-modifying therapies. Conclusion This osteochondral-synovial explant co-culture model captured donor-specific inflammatory and treatment-responsive features of PsA SF-induced pathology, thereby providing a clinically relevant ex vivo platform for studying patient-specific therapeutic responses in PsA.

Generating bioengineered cartilage that recapitulates the depth-dependent phenotype, structure, and function of native articular cartilage remains a challenge. While cartilage is rich in aggrecan and type II collagen, proper function depends on depth-dependent protein expression. Superficial zone chondrocytes (SZCs) secrete proteoglycan-4 (PRG4) to lubricate the cartilage surface. Deep zone chondrocytes produce type X collagen (COLX) to support compressive loading and load transfer to subchondral bone. We previously demonstrated that passaged full-thickness chondrocytes (FTCs) and zonal chondrocytes can re-express cartilage and zone-specific markers following scaffold-free three-dimensional (3D) culture in redifferentiation media. However, in the absence of an instructive matrix, cells expressed low levels of zone-specific proteins and exhibited limited depth-dependent organization. We hypothesize that synthetic extracellular matrix with zone-specific microenvironmental cues will guide zonal differentiation. To this end, passaged primary bovine chondrocytes were encapsulated in a soft, hyaluronan (HA)-based, cell-adhesive, and protease-degradable hydrogel established via bioorthogonal tetrazine (Tz) ligation with norbornene (Nb). When supplemented with TGF{beta}3, FTCs deposited aggrecan and type II collagen with minimal type I collagen. Application of interfacial tetrazine ligation with trans-cyclooctene (TCO) during cell culture resulted in matrix stiffening, leading to upregulation of COLX expression. Conversely, SZCs cultured in soft hydrogels exhibited the greatest PRG4 expression. Establishment of a trilayered construct with region-specific stiffness via the diffusion-controlled reaction promoted PRG4 and COLX expression in defined zones. Together, these findings demonstrate that tunable HA-based hydrogels can enhance zone-specific chondrocyte phenotypes and promote the formation of zonally organized cartilage.

Fracture nonunion remains a major cause of morbidity, yet patient-specific factors associated with impaired healing remain incompletely characterized. Anemia has been associated with adverse orthopaedic outcomes, but its relationship with fracture nonunion is poorly understood. We examined whether pre-fracture anemia, anemia burden, and clinically relevant anemia subtypes were associated with nonunion following tibial or femoral fractures. Using commercial and Medicare fee-for-service claims from 2016 through 2023, we identified adults aged 19 years or older with a tibial or femoral fracture, continuous enrollment during the preceding year and for at least six months after fracture, and no baseline cancer. Pre-fracture anemia was evaluated as any anemia, the number of distinct anemia diagnoses, and nutritional, hemolytic, aplastic, and other anemia subgroups. Nonunion occurring six to eighteen months after fracture was assessed using incidence rates and multivariable-adjusted hazard models. Among 326,673 adults, 149,704 had pre-fracture anemia and 176,969 did not. The crude incidence of nonunion was 42% higher among individuals with anemia than among those without anemia (incidence rate ratio, 1.42; 95% confidence interval, 1.32 to 1.53) and increased with greater anemia burden. After adjustment for demographic and clinical characteristics, including prior fractures at other anatomical sites, pre-fracture anemia remained associated with nonunion following tibial and femoral fractures, with hazard ratios of 1.83 (95% confidence interval, 1.54 to 2.18) and 1.38 (95% confidence interval, 1.26 to 1.50), respectively. Associations were also observed for nutritional and other anemias, whereas estimates for hemolytic and aplastic anemias were limited by few nonunion events. Within the femur, the association was strongest for distal fractures. These findings demonstrate that pre-fracture anemia is independently associated with nonunion. The increase in risk with greater anemia burden and findings across evaluable subgroups suggest that pre-fracture anemia may help identify patients at increased risk of impaired fracture healing.

Spinal cord injury (SCI) causes rapid and severe bone loss in the paralysed lower limbs, particularly at the distal femur and proximal tibia, where fragility fracture risk is high. In vitro nanoscale vibration at 1 kHz has been shown to promote osteogenic differentiation and inhibit osteoclastogenesis, suggesting potential as a targeted mechanical intervention. This study aimed to develop and evaluate a wearable device for delivering and monitoring localised nanovibration at the distal femur in individuals with SCI. The device delivered continuous sinusoidal nanoscale stimulation at 1 kHz via a bone-conduction transducer, with an opposing accelerometer used to monitor transmitted vibration in real time. Design and target-site selection were refined through two healthy-volunteer investigations comparing the distal femur, proximal tibia, and distal tibia. Bovine femur experiments characterised vibration transmission under controlled benchtop conditions. Preliminary repeated-use feasibility was assessed in one individual with motor-complete SCI. Healthy volunteer testing showed that although the ankle initially produced the highest transmitted amplitudes, these were highly variable, and positioning was inconsistent. Within the knee region, the distal femur provided the most practical and repeatable site for a wearable application. In bovine femur experiments, scanning laser vibrometry demonstrated measurable vibration on the condylar surface opposite the transducer, and depth-resolved measurements confirmed that nanoscale vibration remained detectable within bone. A gel interface layer reduced the transmitted amplitude. In the feasibility evaluation, 61 sessions were completed over 14 weeks, with logged accelerometry confirming repeated nanoscale vibration transmission. These findings establish feasibility and support further device optimisation and translational studies.

Background Pain frequently persists in rheumatoid arthritis (RA), despite effective control of inflammation. The mechanisms driving this residual pain remain poorly characterised in individual patients. Methods In 172 patients with established RA and clinically relevant pain (mean NRS 6.5/10) and 80 pain free controls, we combined indicators of inflammatory disease (CRP, joint counts, power Doppler ultrasound), centrally mediated pain (Widespread Pain Index, painDETECT), psychological distress (PHQ ADS) and quantitative sensory testing (QST). Latent profile analysis was applied without predefined thresholds. Results Four phenotypes were identified: a peripheral, low-inflammation/low-central phenotype (38%); a predominantly inflammatory phenotype (7%); and moderate (43%) and severe (12%) centrally mediated phenotypes. Centrally mediated phenotypes reported the highest pain (NRS 8.2), worst disease impact and lowest employment. DAS28 CRP was similar in both the inflammatory and severe centrally mediated phenotypes but for different reasons, swollen joints and CRP versus tender joints , and did not distinguish them. Conditioned pain modulation was impaired relative to controls (p<0.001) and most reduced in the severe centrally mediated phenotype. Psychological distress was the strongest independent predictor of pain severity (model R squared=0.33), whereas inflammatory markers were not. Principal components analysis identified swollen joint count (loading 0.63) and the tender swollen joint difference (loading 0.60) as accessible clinical markers of the inflammatory and centrally mediated phenotypes respectively. Conclusions A data driven approach identified four mechanism-based pain phenotypes in RA. This framework moves pain assessment beyond inflammation alone and provides a basis for testing analgesic strategies to target the predominant pain mechanism in individual patients.

Distal radius fractures (DRFs) can delay return to activities of daily living and social participation because of postoperative pain, temporary joint immobilization, and limited wrist and forearm range of motion. The Ghost System developed at Saitama Prefectural University, Japan, combines visual action observation with tendon vibration stimulation and has shown potential as an adjunct to conventional rehabilitation. This Study Protocol describes a modified Ghost system intended to improve clinical implementation by replacing the head-mounted virtual reality display with iPad-based action observation and by using a wristband-type vibrator. This single-center, single-arm, open-label feasibility trial will enroll 10 adults after palmar locking plate fixation for DRF. The intervention will be delivered twice weekly during outpatient rehabilitation follow-up sessions from the early postoperative period (postoperative days 2-10 after enrollment) through the approved early postoperative rehabilitation period (generally up to postoperative week 8), in parallel with standard rehabilitation practices. Primary feasibility and preliminary clinical outcomes include device fit and acceptability, pain assessed using a 100-mm Visual Analog Scale, and wrist/forearm range of motion. Secondary implementation and safety outcomes include Disabilities of the Arm, Shoulder and Hand (DASH), Patient-Rated Wrist Evaluation (PRWE), Hand20 Questionnaire (HANDS-20), EuroQol 5 Dimensions 5 Levels (EQ-5D-5L), body ownership and hand-illusion questionnaires, setup time, setup errors, adherence, adverse events, and device incidents. We hypothesize that the modified Ghost system will be feasible and acceptable for early postoperative outpatient rehabilitation and will be delivered without serious device-related adverse events. Clinical outcomes will be summarized descriptively to inform a future controlled study rather than to establish efficacy.

ObjectiveTo develop and apply a preclinical functional imaging assay for visualizing and analyzing activated synovial fibroblasts (SFs) at single-cell resolution using high-content imaging. MethodsA multiparametric functional imaging assay was developed to simultaneously interrogate six key cellular processes in cultured SFs from non-inflammatory control (NIC), osteoarthritis (OA) and rheumatoid arthritis (RA) patients. Two complementary fluorescent panels -- comprising LipidTOX, MitoSOX, TMRM, EdU Click-iT, CYTO-ID, and Sir-Lysosome -- collectively captured autophagy dynamics, mitochondrial health, lipid metabolism, and cellular proliferation within a single imaging workflow. Automated image acquisition and quantitative feature extraction via CellProfiler yielded approximately 1,200 morphological and intensity-based features per cell, enabling high-dimensional, unbiased phenotypic profiling at the individual cell level. ResultsApplication of this assay revealed marked heterogeneity in basal cellular functions among SFs stratified by disease state, and robustly differentiated between NIC, OA and RA SFs. Stimulation with inflammatory cytokines (TNF-, IL-1{beta}, IFN{gamma}) and toll-like receptor ligands (LPS, poly I:C) elicited distinct, stimulus-dependent phenotypic responses across disease groups. Multiparametric analysis and feature importance ranking identified IL-1{beta} as a key driver of enhanced autophagic activity, accompanied by significant remodeling of lipid metabolic profiles. ConclusionWe developed a scalable, sensitive approach for dissecting functional heterogeneity in primary SF cultures, revealing previously unappreciated complexity in SF biology across disease states. Our approach provides a robust framework for high-throughput drug screening and identification of candidate therapeutics selectively targeting pathogenic fibroblast functions in inflammatory arthritis.

1.Cancer-induced bone pain (CIBP) occurs in a majority of patients when primary or metastatic cancer develops within the bone. This pain has a significant impact on quality of life, yet there are limited effective treatment options available. Nerve sprouting is a complex mechanism that has been implicated in CIBP. Netrin-1 is a neuronal guidance molecule that is produced by numerous cell types, including cancer cells. In this study we aimed to determine whether netrin-1 inhibition (with NP137 - a humanized IGg1 monoclonal antibody) could ameliorate nerve sprouting, and nociception by extension, in three models of CIBP - osteosarcoma, metastatic breast cancer, and metastatic prostate cancer. Sustained administration of NP137 failed to produce an anti-nociceptive effect in these models, but a delayed onset was observed in the osteosarcoma model. NP137 did not produce a disease-modifying effect, as micro-computed tomography did not reveal reduced bone destruction in the NP137-treated groups. Additionally, there was no nerve fibre density reduction in any of the groups at the late-stage of the disease, suggesting that nerve sprouting occurs in early- to mid-stage CIBP development. Investigation of NP137 exposure indicated that serum levels of NP137 were comparable between the sham and cancer groups. Our study indicates that netrin-1 may play a role in early-stage CIBP development, but inhibition of this mechanism does not produce robust anti-nociception.

Rheumatoid arthritis is a chronic inflammatory joint disease in which progressive destruction of cartilage and bone drives long-term disability. Current disease-modifying therapies target the immune and cytokine networks that sustain synovial inflammation, but none is directed at the chondrocyte, the resident cell responsible for maintaining cartilage matrix. Chondrocyte survival and matrix homeostasis depend on {beta}1-integrin-mediated adhesion to the extracellular matrix, and dysregulated integrin signalling has been implicated in cartilage injury. Here we test the hypothesis that allosteric modulation of {beta}1 integrin, rather than simple adhesion blockade, is chondroprotective. Using the monoclonal antibody JB1a, which binds an epitope in the hybrid domain of {beta}1 integrin and stabilises the receptor in a low-affinity conformation, we show that intra-articular administration produces both functional and structural amelioration of Freunds complete adjuvant (FCA)-induced arthritis in mice. JB1a abolished the FCA-induced increase in joint diameter and hyperalgesia and markedly reduced synovial inflammation, pannus formation and cartilage erosion, with no effect on the contralateral joint and no observed adverse effects. These changes were accompanied by a reduction in chondrocyte apoptosis in vivo. In primary human articular chondrocytes, JB1a abolished interleukin-1{beta} (IL-1{beta})-induced caspase 3/7 activation, reduced IL-8 secretion, and restored the sinusoidal oscillation of intracellular ATP that was otherwise abrogated by IL-1{beta}. In contrast, the adhesion-blocking, integrin-clustering antibody 6S6 activated caspase 3/7 and amplified IL-1{beta}-induced IL-8 secretion, indicating that the therapeutic effect is a property of the specific mode of receptor engagement rather than of adhesion blockade per se. These findings identify {beta}1-integrin conformational state as a determinant of chondrocyte energy homeostasis and survival, and nominate allosteric {beta}1-integrin modulation as a mechanistically distinct, chondrocyte-directed therapeutic strategy in inflammatory arthritis.

Purpose: Lymphatic system plays a critical role in fluid regulation and immune response. The conjunctiva of the ocular surface is endowed with a rich lymphatic network, and it provides an ideal site to study lymphatic structure and function. The purpose of this study is to investigate potential morphological and functional changes of conjunctival lymphatics with aging, a time-dependent biological deterioration process. Methods: Young and aged fluorescently labeled transgenic mice of Prox-1, the master control gene for lymphatic determination, were used in the study. For morphological assessment, conjunctival lymphatic vessels were examined in vivo by our advanced live imaging system. For functional analysis, lymphatic drainage efficiencies were measured by fluorescently labeled tracer injection. Results: Compared to young mice, both vascular branching points and intraluminal valves were significantly reduced in conjunctival lymphatic vessels of aged mice. Moreover, lymphatic functional deterioration and drainage deficiencies, such as fluid leakage and reflux, were also detected in the aged condition. Conclusions: Conjunctival lymphatic system undergoes morphological as well as functional changes with aging. Further investigation into this phenomenon may provide novel insights into lymphatic and age-related diseases inside and outside the eye.

Objective: Photobiomodulation therapy has emerged as a promising modality to facilitate scar healing and pain management in dermatology and plastic surgery. However, its role in postoperative care following spine surgeries remains understudied. This double-blinded, placebo-controlled study aimed to investigate the effects of photobiomodulation in patients with chronic lower back pain undergoing lumbar decompression, with postoperative wound healing as the primary outcome and pain reduction and functional recovery as secondary outcomes. Methods: Patients were randomized to receive either active photobiomodulation braces (N=13) or placebo braces (N=12). Follow-up assessments were performed at 2, 4, 6, 8, and 12 weeks postoperatively. Outcomes included wound healing (Stony Brook Scar Evaluation Scale), back and leg pain (Visual Analog Scale), quality of life (EuroQol 5D), and functional status (Oswestry Disability Index). Results: Compared to the placebo group, the photobiomodulation treatment group had a 4.12-fold cumulative improvement in final scar scores, with significant between-group differences at postoperative weeks 6, 8, and 12 (p = 0.0062, 0.010, 0.042). Among patients with severe preoperative disability, treatment resulted in a 1.89-fold faster improvement in back pain (p=0.025) and a 1.80-fold faster improvement in ODI scores (p=0.025); and superior treatment effect on wound healing were again observed at weeks 6, 8, and 12. Among patients with poor initial scars, treatment led to a significantly better scar outcome than placebo at week 6 and a 1.94-fold faster EQ5D improvement (p=0.052), with significant gains observed as early as two weeks after surgery. There were no adverse events associated with photobiomodulation treatment. Conclusions: Photobiomodulation significantly promoted postoperative wound healing following lumbar decompression surgery, with therapeutic benefits preserved even in patients with poor baseline scar scores and functional impairment. This indicates that the efficacy of photobiomodulation is not limited by the initial scar condition or disability, supporting its broad clinical applicability. Additionally, patients with severe preoperative disability experienced greater benefits from photobiomodulation than placebo, including faster reduction in back pain and more rapid improvement in functional capacity, highlighting its role in postoperative pain management and rehabilitation. These therapeutic effects are likely mediated by photobiomodulation-induced reduction of inflammation and enhancement of tissue repair. Together, this study suggests that photobiomodulation can be a promising adjunct therapy to facilitate postoperative recovery in patients undergoing spine surgery.

Abstract Background: Non-specific chronic low back pain (NSCLBP) is a major cause of disability worldwide and is associated with low-grade systemic inflammation. This study investigated the effects of aerobic exercise on inflammatory biomarkers, pain intensity, and quality of life among individuals with NSCLBP. Methods: In this parallel-group randomized controlled trial, 41 participants with NSCLBP were allocated to either an aerobic exercise plus health education group (n=21) or a health education-only control group (n=20). Participants in the intervention group completed supervised aerobic cycling three times weekly for 12 weeks. Outcome assessors and laboratory personnel were blinded to group allocation. Outcomes were measured at baseline, Week 8, and Week 12. Results: Interaction effects were observed for TNF- (p=0.046), IL-6 (p<0.001), hs-CRP (p<0.001), and pain intensity (p<0.001). Significant improvements were also observed across all WHOQOL-BREF quality-of-life domains (all p<0.05). After adjustment for baseline values and age, participants in the intervention group had significantly lower Week 12 IL-6 (p=0.013), hs-CRP (p<0.001), and pain intensity (p<0.001) than controls. No serious adverse events were reported. Conclusions: Aerobic exercise combined with health education produced greater improvements in inflammatory biomarkers, pain intensity, and quality of life than health education alone among individuals with NSCLBP. These findings support the integration of structured aerobic exercise into rehabilitation programmes for chronic low back pain. Keywords: Non-specific chronic low back pain; aerobic exercise; inflammation; IL-6; hs-CRP; pain intensity; quality of life; randomized controlled trial.

Sutures are the primary sites of cranial bone growth, allowing the skull to accommodate the growing brain. External mechanical stimulus has been shown to delay suture fusion and induce tissue remodelling. Recent studies suggest that in vivo cyclic bone loading increased proliferation of mesenchymal stem cells (MSC) in the coronal suture. The overall aim of this study was to understand how many loading sessions (exposure-response) and how long after loading (time-course) did MSC proliferation increase in the coronal suture. In the exposure-response analysis, mice underwent 1, 3, or 5 loading sessions between Postnatal day 7 (P7) and P11, and in the time-course analysis, treated mice underwent 10 loading sessions between P7 and P21. Loading sessions were 10 minutes at a frequency of 1 Hz and a force of 10 g (0.1 N). The loading tip was positioned on the posterior aspect of the left frontal bone, dorsal to the coronal suture. The EdU marker shows a statistically significant increase in proliferation after one loading session and a decrease after three loading sessions. The PCNA marker shows a statistically significant increase after three and five loading sessions. The exposure-response analysis showed that when the results of both markers are combined, levels of proliferation cannot be interpreted until at least five loading sessions have been completed, after which a clear increase in proliferation was observed. In the time-course analysis, proliferation was highest immediately after the final treatment session and 24 hours after the final loading session the effects of mechanical bone loading gradually returned to baseline.

Background: Psoriatic arthritis (PsA) is an inflammatory condition involving joints, tendon-bone entheses and synovium that can develop in individuals with psoriasis. Early, accurate clinical diagnosis remains difficult. Extracellular vesicles (EVs) carry proteins and miRNAs that Methods: PubMed and Embase were searched from inception through May 21st, 2026, and human studies examining EV-associated protein or miRNA biomarkers in PsA and related psoriatic or inflammatory diseases were included, with risk of bias assessed using a modified Newcastle-Ottawa Scale and diagnostic accuracy summarized using HSROC/BRMA models when data were sufficient. Results: Seven studies met the inclusion criteria, including 119 individuals with PsA (weighted mean age: 49.8 years; 43.7% female), 205 individuals with non-PsA psoriasis (weighted mean age: 46.4 years; female %: NA), 55 controls (weighted mean age: 44.5 years; 38.2% female), and 50 individuals with other inflammatory joint disorders (weighted mean age: 58.0 years; 58.0% female). EV-associated protein markers demonstrated heterogeneous findings related to immune, vascular, inflammatory, and osteoimmunological signaling. Only 4.2% (4/95) of miRNAs were consistently identified across studies comparing PsA with non-PsA psoriasis, with lower overlap (1.5%, 1/67) in studies comparing PsA with controls. ROC meta-analysis suggested preliminary diagnostic potential, particularly for distinguishing PsA from non-PsA psoriasis, although evidence was constrained by small study numbers. Conclusions: EV-associated proteins and miRNAs are potential biomarker candidates for PsA, reflecting inflammatory, vascular, and osteoimmunological processes underlying disease pathophysiology. However, current evidence remains preliminary and limited by small cohorts, methodological heterogeneity, and inconsistent reporting across studies.

Muscle satellite cells (SCs) regenerate skeletal muscle, but their regenerative capacity declines with age, in part due to extracellular matrix (ECM) remodeling and aberrant fibroblast activation within the SC niche. In regenerating young mouse muscle, fibronectin remodeling is transient, whereas in aged mouse muscle, fibronectin remodeling is prolonged and disorganized. Fibroblasts in aged mice are activated, increasing fibronectin deposition and expressing elevated -smooth muscle actin (SMA), which negatively influence SC fate. We develop a viscoelastic hydrogel co-encapsulation system, enabling three-dimensional co-culture of intact myofibers with primary fibroblasts. Using this 3D co-culture system, we show that fibroblasts from young mice support SC quiescence and self-renewal, whereas fibroblasts from aged mice aberrantly activate SCs and promote their differentiation on myofibers isolated from either young or aged mice. Knocking down fibronectin (Fn1) in fibroblasts from aged mice partially restores SC function, promoting quiescence and limiting differentiation. Using a novel 3D hydrogel co-culture system, we demonstrate that fibroblast-deposited fibronectin is a key age-associated regulator negatively affecting SC fate within the SC niche of aged mice.