scholarly journals Global Gene Expression Analysis Identifies Age-Related Differences in Knee Joint Transcriptome during the Development of Post-Traumatic Osteoarthritis in Mice

2020 ◽  
Vol 21 (1) ◽  
pp. 364 ◽  
Author(s):  
Aimy Sebastian ◽  
Deepa K. Murugesh ◽  
Melanie E. Mendez ◽  
Nicholas R. Hum ◽  
Naiomy D. Rios-Arce ◽  
...  
Keyword(s):  
Knee Joint ◽  
Age Groups ◽  
Knee Joints ◽  
Compression Injury ◽  
Post Injury ◽  
Transcriptional Responses ◽  
Molecular Changes ◽  
Age Related ◽  
Post Traumatic ◽  
Old Mice

Aging and injury are two major risk factors for osteoarthritis (OA). Yet, very little is known about how aging and injury interact and contribute to OA pathogenesis. In the present study, we examined age- and injury-related molecular changes in mouse knee joints that could contribute to OA. Using RNA-seq, first we profiled the knee joint transcriptome of 10-week-old, 62-week-old, and 95-week-old mice and found that the expression of several inflammatory-response related genes increased as a result of aging, whereas the expression of several genes involved in cartilage metabolism decreased with age. To determine how aging impacts post-traumatic arthritis (PTOA) development, the right knee joints of 10-week-old and 62-week-old mice were injured using a non-invasive tibial compression injury model and injury-induced structural and molecular changes were assessed. At six-week post-injury, 62-week-old mice displayed significantly more cartilage degeneration and osteophyte formation compared with young mice. Although both age groups elicited similar transcriptional responses to injury, 62-week-old mice had higher activation of inflammatory cytokines than 10-week-old mice, whereas cartilage/bone metabolism genes had higher expression in 10-week-old mice, suggesting that the differential expression of these genes might contribute to the differences in PTOA severity observed between these age groups.

scholarly journals Robust Characterization of Non-Invasive Post-Traumatic Osteoarthritis Mouse Model

2021 ◽  
Author(s):  
Fazal-Ur-Rehman Bhatti ◽  
Yong-Hoon Jeong ◽  
Do-Gyoon Kim ◽  
David D Brand ◽  
Karen A Hasty ◽  
...  
Keyword(s):  
Mouse Model ◽  
Knee Joint ◽  
Mouse Models ◽  
Mechanical Loading ◽  
Left Knee ◽  
Knee Joints ◽  
Control Group ◽  
Molecular Changes ◽  
Non Invasive ◽  
Post Traumatic

Objective: Biochemical and molecular changes involved in the pathophysiology of post-traumatic arthritis (PTOA) have not been fully understood. This study used non-invasive mouse models to study biochemical, biomechanical and pain-related behavior changes induced in mice following repetitive mechanical knee loading. Mouse models were used to reflect the effects of the early stages of PTOA in humans. Methods: Forty-eight twelve week old male mice were obtained for three groups: normal control without mechanical loading, trauma (24 hours after loading), and PTOA (early OA) groups. For the non-invasive PTOA mouse model, cyclic comprehensive loading (9 N) was applied on the left knee joint of each mouse. Biochemical and molecular changes induced by mechanical loading were analyzed after loading was completed. Blood and cartilage were collected and further examined using gene expression analysis. Grading of the tissue sections was completed using the osteoarthritis research society international (OARSI) scale. Biomechanical features of mechanically loaded knee joints were determined after 24 hours (Trauma) and three weeks (PTOA) post-mechanical loading sessions to examine the development of PTOA, respectively. Results: The loaded left knee joint showed a greater ROS/RNS signal than the right knee that was not loaded. There was an increase in cartilage damage and MMP activity in the affected knee as the intensity of MabCII680 and MMP750 signal increased in the mechanical loaded joints as compared to unloaded control knee joints. There was also an increase in the difference of viscoelastic energy dissipation ability (tan δ) in PTOA. The OA score increased significantly in mechanically loaded knee joints. Conclusion: This study showed that biomechanical, biochemical, and behavioral characteristics of the murine PTOA groups are significantly different from the control group. These results validate that the current mouse model can be used for translational studies to examine PTOA.

Low-dose aspirin prevents age-related endothelial dysfunction in a mouse model of physiological aging

2008 ◽  
Vol 294 (4) ◽  
pp. H1562-H1570 ◽  
Author(s):  
Hélène Bulckaen ◽  
Gaétan Prévost ◽  
Eric Boulanger ◽  
Géraldine Robitaille ◽  
Valérie Roquet ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Endothelial Dysfunction ◽  
Protective Effect ◽  
Structural Changes ◽  
Low Dose ◽  
Age Groups ◽  
Dose Aspirin ◽  
Age Related ◽  
Low Dose Aspirin ◽  
Old Mice

The age-related impairment of endothelium-dependent vasodilatation contributes to increased cardiovascular risk in the elderly. For primary and secondary prevention, aspirin can reduce the incidence of cardiovascular events in this patient population. The present work evaluated the effect of low-dose aspirin on age-related endothelial dysfunction in C57B/J6 aging mice and investigated its protective antioxidative effect. Age-related endothelial dysfunction was assessed by the response to acetylcholine of phenylephrine-induced precontracted aortic segments isolated from 12-, 36-, 60-, and 84-wk-old mice. The effect of low-dose aspirin was examined in mice presenting a decrease in endothelial-dependent relaxation (EDR). The effects of age and aspirin treatment on structural changes were determined in mouse aortic sections. The effect of aspirin on the oxidative stress markers malondialdehyde and 8-hydroxy-2′-deoxyguanosine (8-OhdG) was also quantified. Compared with that of 12-wk-old mice, the EDR was significantly reduced in 60- and 84-wk-old mice ( P < 0.05); 68-wk-old mice treated with aspirin displayed a higher EDR compared with control mice of the same age (83.9 ± 4 vs. 66.3 ± 5%; P < 0.05). Aspirin treatment decreased 8-OHdG levels ( P < 0.05), but no significant effect on intima/media thickness ratio was observed. The protective effect of aspirin was not observed when treatment was initiated in older mice (96 wk of age). It was found that low-dose aspirin is able to prevent age-related endothelial dysfunction in aging mice. However, the absence of this effect in the older age groups demonstrates that treatment should be initiated early on. The underlying mechanism may involve the protective effect of aspirin against oxidative stress.

scholarly journals Injectable mechanical pillows for attenuation of load-induced post-traumatic osteoarthritis

2019 ◽  
Vol 6 (4) ◽  
pp. 211-219
Author(s):  
Derek T Holyoak ◽  
Tibra A Wheeler ◽  
Marjolein C H van der Meulen ◽  
Ankur Singh
Keyword(s):  
Knee Joint ◽  
Joint Damage ◽  
Mechanical Trauma ◽  
Protective Effects ◽  
Post Injury ◽  
On Demand ◽  
Post Traumatic ◽  
Anti Inflammatory

Abstract Osteoarthritis (OA) of the knee joint is a degenerative disease initiated by mechanical stress that affects millions of individuals. The disease manifests as joint damage and synovial inflammation. Post-traumatic osteoarthritis (PTOA) is a specific form of OA caused by mechanical trauma to the joint. The progression of PTOA is prevented by immediate post-injury therapeutic intervention. Intra-articular injection of anti-inflammatory therapeutics (e.g. corticosteroids) is a common treatment option for OA before end-stage surgical intervention. However, the efficacy of intra-articular injection is limited due to poor drug retention time in the joint space and the variable efficacy of corticosteroids. Here, we endeavored to characterize a four-arm maleimide-functionalized polyethylene glycol (PEG-4MAL) hydrogel system as a ‘mechanical pillow’ to cushion the load-bearing joint, withstand repetitive loading and improve the efficacy of intra-articular injections of nanoparticles containing dexamethasone, an anti-inflammatory agent. PEG-4MAL hydrogels maintained their mechanical properties after physiologically relevant cyclic compression and released therapeutic payload in an on-demand manner under in vitro inflammatory conditions. Importantly, the on-demand hydrogels did not release nanoparticles under repetitive mechanical loading as experienced by daily walking. Although dexamethasone had minimal protective effects on OA-like pathology in our studies, the PEG-4MAL hydrogel functioned as a mechanical pillow to protect the knee joint from cartilage degradation and inhibit osteophyte formation in an in vivo load-induced OA mouse model.

scholarly journals Validation of an Empirical Damage Model for Aging and in Vivo Injury of the Murine Patellar Tendon

2013 ◽  
Vol 135 (4) ◽  
Author(s):  
Mark R. Buckley ◽  
Andrew A. Dunkman ◽  
Katherine E. Reuther ◽  
Akash Kumar ◽  
Lydia Pathmanathan ◽  
...  
Keyword(s):  
Soft Tissues ◽  
Damage Model ◽  
Damage Parameter ◽  
Post Injury ◽  
Equilibrium Stress ◽  
Physiological Loading ◽  
Age Related ◽  
Injury Group ◽  
Old Mice

While useful models have been proposed to predict the mechanical impact of damage in tendon and other soft tissues, the applicability of these models for describing in vivo injury and age-related degeneration has not been investigated. Therefore, the objective of this study was to develop and validate a simple damage model to predict mechanical alterations in mouse patellar tendons after aging, injury, or healing. To characterize baseline properties, uninjured controls at age 150 days were cyclically loaded across three strain levels and five frequencies. For comparison, damage was induced in mature (120 day-old) mice through either injury or aging. Injured mice were sacrificed at three or six weeks after surgery, while aged mice were sacrificed at either 300 or 570 days old. Changes in mechanical properties (relative to baseline) in the three week post-injury group were assessed and used to develop an empirical damage model based on a simple damage parameter related to the equilibrium stress at a prescribed strain (6%). From the derived model, the viscoelastic properties of the 300 day-old, 570 day-old, and six week post-injury groups were accurately predicted. Across testing conditions, nearly all correlations between predicted and measured parameters were statistically significant and coefficients of determination ranged from R2 = 0.25 to 0.97. Results suggest that the proposed damage model could exploit simple in vivo mechanical measurements to predict how an injured or aged tendon will respond to complex physiological loading regimens.

scholarly journals Comparative Transcriptomics Identifies Novel Genes and Pathways Involved in Post-Traumatic Osteoarthritis Development and Progression

2018 ◽  
Vol 19 (9) ◽  
pp. 2657 ◽  
Author(s):  
Aimy Sebastian ◽  
Jiun Chang ◽  
Melanie Mendez ◽  
Deepa Murugesh ◽  
Sarah Hatsell ◽  
...  
Keyword(s):  
Gene Expression ◽  
Molecular Mechanisms ◽  
Cruciate Ligament ◽  
Cartilage Damage ◽  
Acl Injury ◽  
The Other ◽  
Knee Joints ◽  
Mouse Strains ◽  
Post Injury ◽  
Post Traumatic

Anterior cruciate ligament (ACL) injuries often result in post-traumatic osteoarthritis (PTOA). To better understand the molecular mechanisms behind PTOA development following ACL injury, we profiled ACL injury-induced transcriptional changes in knee joints of three mouse strains with varying susceptibility to OA: STR/ort (highly susceptible), C57BL/6J (moderately susceptible) and super-healer MRL/MpJ (not susceptible). Right knee joints of the mice were injured using a non-invasive tibial compression injury model and global gene expression was quantified before and at 1-day, 1-week, and 2-weeks post-injury using RNA-seq. Following injury, injured and uninjured joints of STR/ort and injured C57BL/6J joints displayed significant cartilage degeneration while MRL/MpJ had little cartilage damage. Gene expression analysis suggested that prolonged inflammation and elevated catabolic activity in STR/ort injured joints, compared to the other two strains may be responsible for the severe PTOA phenotype observed in this strain. MRL/MpJ had the lowest expression values for several inflammatory cytokines and catabolic enzymes activated in response to ACL injury. Furthermore, we identified several genes highly expressed in MRL/MpJ compared to the other two strains including B4galnt2 and Tpsab1 which may contribute to enhanced healing in the MRL/MpJ. Overall, this study has increased our knowledge of early molecular changes associated with PTOA development.

scholarly journals Serine and Glycine Are Essential for Skeletal Muscle Regeneration Following Injury

2020 ◽  
Vol 4 (Supplement_2) ◽  
pp. 81-81
Author(s):  
Anna Thalacker-Mercer ◽  
Jamie Blum ◽  
Brandon Gheller
Keyword(s):  
Gene Expression ◽  
Skeletal Muscle ◽  
Essential Amino Acids ◽  
Regenerative Process ◽  
Skeletal Muscle Regeneration ◽  
Post Injury ◽  
Foreign Study ◽  
Funding Sources ◽  
Age Related ◽  
Old Mice

Abstract Objectives Skeletal muscle (SkM) regeneration post injury is reliant on SkM-specific stem cells (muscle progenitor cells [MPCs]) and a well-orchestrated myogenic program. The regenerative process is impaired with advancing age, potentiating pathological SkM remodeling (infiltration of fat and fibrotic tissues). We have previously demonstrated that the nutritionally non-essential amino acids serine (Ser) and glycine (Gly) are required for early stages of SkM regeneration (MPC proliferation). However, Ser and Gly availability (SkM and circulating) declines with aging. The objective was to test the hypothesis that reduced endogenous Ser/Gly during regeneration promotes pathological SkM remodeling in aged animals. Methods Old mice (∼20 months of age) were given a Ser/Gly depleted diet (SGdep) or an isonitrogenous, isoenergetic diet containing Ser/Gly (SGcont) for 4 weeks followed by notexin-induced injury to the tibialis anterior (TA) SkM. At 28 days post injury the TA was harvested and histological analysis of SkM morphology (H&E and immunofluorescence [IF]) and gene expression analyses (qPCR) were completed. Results Old mice receiving the SGdep diet had a shift toward reduced myofiber size and enhanced adipocyte infiltration in the SkM. Adipocyte infiltration was confirmed with IF of perilipin-1, an adipocyte marker. Uninjured mice on the SGdep diet did not demonstrate altered SkM morphology. Gene expression analysis of differentially expressed genes underlying SkM remodeling (reduced myofiber size and increased fat infiltration) with SGdep is ongoing. Conclusions Reduced Ser and Gly availability following injury instigates SkM remodeling in old mice, which could explain in part age-related impairments in SkM regeneration. This research underscores the essentiality of Ser and Gly for the SkM regenerative process particularly with advancing age. Funding Sources Canadian Institutes of Health Research Doctoral Foreign Study Award to BG.

Age-related impairment of the transcriptional responses to oxidative stress in the mouse heart

2003 ◽  
Vol 13 (2) ◽  
pp. 119-127 ◽  
Author(s):  
Michael G. Edwards ◽  
Deepayan Sarkar ◽  
Roger Klopp ◽  
Jason D. Morrow ◽  
Richard Weindruch ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Gene Expression ◽  
Age Groups ◽  
Transcriptional Level ◽  
Mouse Heart ◽  
Mrna Levels ◽  
Middle Aged ◽  
Transcriptional Responses ◽  
Age Related ◽  
Young Mice

To investigate the transcriptional response to oxidative stress in the heart and how it changes with age, we examined the cardiac gene expression profiles of young (5-mo-old), middle-aged (15-mo-old), and old (25-mo-old) C57BL/6 mice treated with a single intraperitoneal injection of paraquat (50 mg/kg). Mice were killed at 0, 1, 3, 5, and 7 h after paraquat treatment, and the gene expression profile was obtained with high-density oligonucleotide microarrays. Of 9,977 genes represented on the microarray, 249 transcripts in the young mice, 298 transcripts in the middle-aged mice, and 256 transcripts in the old mice displayed a significant change in mRNA levels (ANOVA, P < 0.01). Among these, a total of 55 transcripts were determined to be paraquat responsive for all age groups. Genes commonly induced in all age groups include those associated with stress, inflammatory, immune, and growth factor responses. Interestingly, only young mice displayed a significant increase in expression of all three isoforms of GADD45, a DNA damage-responsive gene. Additionally, the number of immediate early response genes (IEGs) found to be induced by paraquat was considerably higher in the younger animals. These results demonstrate that, at the transcriptional level, there is an age-related impairment of specific inducible pathways in the response to oxidative stress in the mouse heart.

scholarly journals Single-Cell RNA-Seq Reveals Transcriptomic Heterogeneity and Post-Traumatic Osteoarthritis-Associated Early Molecular Changes in Mouse Articular Chondrocytes

Cells ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 1462
Author(s):  
Aimy Sebastian ◽  
Jillian L. McCool ◽  
Nicholas R. Hum ◽  
Deepa K. Murugesh ◽  
Stephen P. Wilson ◽  
...  
Keyword(s):  
Articular Cartilage ◽  
Single Cell ◽  
Articular Chondrocytes ◽  
Cartilage Degeneration ◽  
Cell Types ◽  
Knee Joints ◽  
Molecular Changes ◽  
Post Traumatic ◽  
Joint Trauma ◽  
Functional Profiles

Articular cartilage is a connective tissue lining the surfaces of synovial joints. When the cartilage severely wears down, it leads to osteoarthritis (OA), a debilitating disease that affects millions of people globally. The articular cartilage is composed of a dense extracellular matrix (ECM) with a sparse distribution of chondrocytes with varying morphology and potentially different functions. Elucidating the molecular and functional profiles of various chondrocyte subtypes and understanding the interplay between these chondrocyte subtypes and other cell types in the joint will greatly expand our understanding of joint biology and OA pathology. Although recent advances in high-throughput OMICS technologies have enabled molecular-level characterization of tissues and organs at an unprecedented resolution, thorough molecular profiling of articular chondrocytes has not yet been undertaken, which may be in part due to the technical difficulties in isolating chondrocytes from dense cartilage ECM. In this study, we profiled articular cartilage from healthy and injured mouse knee joints at a single-cell resolution and identified nine chondrocyte subtypes with distinct molecular profiles and injury-induced early molecular changes in these chondrocytes. We also compared mouse chondrocyte subpopulations to human chondrocytes and evaluated the extent of molecular similarity between mice and humans. This work expands our view of chondrocyte heterogeneity and rapid molecular changes in chondrocyte populations in response to joint trauma and highlights potential mechanisms that trigger cartilage degeneration.

scholarly journals Periostin loss-of-function protects mice from post-traumatic and age-related osteoarthritis

2021 ◽  
Vol 23 (1) ◽  
Author(s):  
Mukundan Attur ◽  
Xin Duan ◽  
Lei Cai ◽  
Tianzhen Han ◽  
Weili Zhang ◽  
...  
Keyword(s):  
Serum Levels ◽  
Cartilage Degeneration ◽  
Rna Seq ◽  
Loss Of Function ◽  
Age Related ◽  
Synovial Lining Cell ◽  
Bone Changes ◽  
Post Traumatic ◽  
Old Mice

Abstract Background Elevated levels of periostin (Postn) in the cartilage and bone are associated with osteoarthritis (OA). However, it remains unknown whether Postn loss-of-function can delay or prevent the development of OA. In this study, we sought to better understand the role of Postn in OA development and assessed the functional impact of Postn deficiency on post-traumatic and age-related OA in mice. Methods The effects of Postn deficiency were studied in two murine experimental OA models using Postn−/− (n = 32) and littermate wild-type (wt) mice (n = 36). Post-traumatic OA was induced by destabilization of the medial meniscus (DMM) in 10-week-old mice (n = 20); age-related OA was analyzed in 24-month-old mice (n = 13). Cartilage degeneration was assessed histologically using the OARSI scoring system, and synovitis was evaluated by measuring the synovial lining cell layer and the cells density in the synovial stroma. Bone changes were measured by μCT analysis. Serum levels of Postn were determined by ELISA. Expression of Postn and collagenase-3 (MMP-13) was measured by immunostaining. RNA-seq was performed on chondrocytes isolated from 21-day old Postn−/− (n = 3) and wt mice (n = 3) to discover genes and pathways altered by Postn knockout. Results Postn−/− mice exhibited significantly reduced cartilage degeneration and OARSI score relative to wt mice in post-traumatic OA after 8 weeks (maximum: 2.37 ± 0.74 vs. 4.00 ± 1.20, P = 0.011; summed: 9.31 ± 2.52 vs. 21.44 ± 6.01, P = 0.0002) and spontaneous OA (maximum: 1.93 ± 0.45 vs. 3.58 ± 1.16, P = 0.014; summed: 6.14 ± 1.57 vs. 11.50 ± 3.02, P = 0.003). Synovitis was significantly lower in Postn−/− mice than wt only in the DMM model (1.88 ± 1.01 vs. 3.17 ± 0.63; P = 0.039). Postn−/− mice also showed lower trabecular bone parameters such as BV/TV, vBMD, Tb.Th, and Tb.N and high Tb. Sp in both models. Postn−/− mice had negligible levels of serum Postn compared with wt. Immunofluorescent studies of cartilage indicated that Postn−/− mice expressed lower MMP-13 levels than wt mice. RNA-seq revealed that cell-cell-adhesion and cell-differentiation processes were enriched in Postn−/− mice, while those related to cell-cycle and DNA-repair were enriched in wt mice. Conclusions Postn deficiency protects against DMM-induced post-traumatic and age-related spontaneous OA. RNA-seq findings warrant further investigations to better understand the mechanistic role of Postn and its potential as a therapeutic target in OA.

scholarly journals EPCR Deficiency Prevents Development of Hemophilic Arthropathy

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 159-159
Author(s):  
Jhansi Magisetty ◽  
Usha Pendurthi ◽  
Charles T. Esmon ◽  
L. Vijaya Mohan Rao
Keyword(s):  
Single Dose ◽  
Synovial Fluid ◽  
Knee Joint ◽  
Protein C ◽  
Model Systems ◽  
Knee Joints ◽  
Coagulation Cascade ◽  
Clotting Factor ◽  
Post Injury ◽  
Hemophilic Arthropathy

Recent studies from our laboratory showed that clotting factor VIIa (FVIIa), whose primary function is to initiate the coagulation cascade following its binding to procoagulant cofactor tissue factor (TF), also binds anticoagulant cofactor, endothelial cell protein C receptor (EPCR). EPCR plays a key role in the activated protein C (APC)-mediated anticoagulant pathway by promoting the activation of protein C bound to it. Pharmacological concentrations of rFVIIa could compete with protein C for the EPCR and downregulate APC generation by preventing protein C binding to the EPCR. Our recent studies showed that FVIIa binding to EPCR also induces barrier-protective and anti-inflammatory effects both in vitro and in vivo model systems. Bio-distribution of rFVIIa in mice revealed that a small fraction of rFVIIa administed to mice i.v. accumulates in knee joints and retained there for three to seven days. The present study was conducted to investigate the relevance of FVIIa binding to EPCR in pharmacological FVIIa treatment of joint disease in hemophilia. For this, we first generated hemophilia A mice lacking EPCR or overexpressing EPCR. To generate EPCR deficient FVIII-/- mice, Procrflox/flox and Procr+/floxMeox2+/cre mice were first backcrossed with FVIII-/- mice to generate Procrflox/flox/FVIII-/- and Meox2+/cre/FVIII-/- mice. EPCR deficient FVIII-/- mice (Procr-/-/FVIII-/-) were generated by breeding female Procrflox/flox/FVIII-/- with male Procr+/floxMeox2+/cre /FVIII-/- mice. EPCR- overexpressing FVIII-/- were generated by crossing Tie2-EPCR mice with FVIII-/- mice. We induced joint bleeding in FVIII-/-, EPCR deficient FVIII-/-, and EPCR-overexpressing FVIII-/- mice by needle puncture injury. Right knee joint intra articular space was pierced with 30G needle to induce joint bleeding; left knee joint served as an uninjured control. Injured mice were treated with a single dose of rFVIIa (1 mg/kg) at 20 min following the injury or three doses of rFVIIa (1 mg/Kg) at 20 min, 24 h and 72 h following the injury. In controls, saline was administered in place of rFVIIa. The knee injury was evaluated by measuring knee joint diameter and visual bleeding score. At the end of 14 days post injury, mice were euthanized, and the knee joints were excised and fixed for immunohistochemical analysis. Hemophilic arthropathy was evaluated by scoring a set of pathological parameters (e.g., synovial hyperplasia, neoangiogenesis, presence of blood, iron score, villus formation, and cartilage degeneration). A subset of mice was used to collect synovial fluid at 7 days post injury. Assessment of joint bleeding at 5 h following the needle injury, by extracting and measuring hemoglobin levels in joint tissues and monitoring hematocrit, showed an equal amount of bleeding in all three genotypes of mice (FVIII-/-, EPCR deficient FVIII-/-, and EPCR-overexpressing FVIII-/- mice). Administration of three doses of FVIIa was effective in preventing hemophilic arthropathy in FVIII-/- and EPCR-overexpressing FVIII-/- mice, whereas a single dose of rFVIIa had a minimal effect in reducing hemophilic arthropathy. Interestingly, a single dose of FVIIa fully corrected the needle injury-induced hemophilic arthropathy in EPCR-deficient FVIII-/- mice. More importantly, EPCR-deficient FVIII-/- mice failed to develop full-blown hemophiic arthropathy even in the absence of any treatment. Measurement of inflammatory cytokines in the synovial fluid showed a robust increase in IL-6 levels in FVIII-/- mice and a single dose of FVIIa substantially reduced IL-6 levels. Interestingly, IL-6 levels in the synovial fluid of injured EPCR-overexpressing FVIII-/- mice were markedly higher compared to injured FVIII-/- mice, three doses of rFVIIa was required to attain a significant reduction in IL-6 levels in these mice. In contrast to these data, we found very little IL-6 levels in the synovial fluids of injured EPCR-deficient FVIII-/- mice. Overall, these data indicate that EPCR levels profoundly influence hemophilic arthorpathy. EPCR-deficiency protects from development hemophilic arthropathy because down-regulation of APC generation in EPCR deficiency could allow sufficient thrombin generation in hemophilia to prevent joint bleeding and bleeding-associated inflammation. Disclosures Rao: Takeda: Research Funding.

Sign in / Sign up

Export Citation Format

Share Document