Pathogenesis Of Hemophilic Arthropathy Research Articles

Biomarkers Involved in the Pathogenesis of Hemophilic Arthropathy.

Hemophilia, which is a rare disease, results from congenital deficiencies of coagulation factors VIII and IX, respectively, leading to spontaneous bleeding into joints, resulting in hemophilic arthropathy (HA). HA involves complex processes, including synovial proliferation, angiogenesis, and tissue remodeling. Despite ongoing research, factors contributing to HA progression, especially in adults with severe HA experiencing joint pain, remain unclear. Blood markers, particularly collagen-related ones, have been explored to assess joint health in hemophilia. For example, markers like CTX-I and CTX-II reflect bone and cartilage turnover, respectively. Studies indicate elevated levels of certain markers post-bleeding episodes, suggesting joint health changes. However, longitudinal studies on collagen turnover and basement membrane or endothelial cell markers in relation to joint outcomes, particularly during painful episodes, are scarce. Given the role of the CX3CL1/CX3XR1 axis in arthritis, other studies investigate its involvement in HA. The importance of different inflammatory and bone damage biomarkers should be assessed, alongside articular cartilage and synovial membrane morphology, aiming to enhance understanding of hemophilic arthropathy progression.

Proteomic exploration of potential blood biomarkers in haemophilic arthropathy.

The pathophysiology of haemophilic arthropathy (HA) is complex and largely undefined. Proteomic analyses provide insights into the intricate mechanisms of the HA.Our study aimed to identify differentially expressed proteins in relation to the severity of HA, explore their pathophysiological roles, and evaluate their potential as HA biomarkers. Our cross-sectional observational study encompassed 30 HA patients and 15 healthy subjects. Plasma samples were pooled into three groups of 15 samples from those with severe haemophilic arthropathy (sHA), mild haemophilic arthropathy (mHA) and healthy controls. Proteomic analysis was performed using liquid chromatography-mass spectrometry. The severity of HA was assessed using the World Federation of Haemophilia Physical Examination Score and ultrasonography following the Haemophilia Early Arthropathy Detection with Ultrasound (HEAD-US) guidelines. A total of 788 proteins were identified, with 97% of the uniquely identified proteins being expressed in all analysed groups. We identified several up and downregulated proteins across the groups that were mainly related to inflammatory and immunity-modulating processes, as well as joint degeneration. We highlighted ten proteins relevant for the development of HA: cathepsin G, endoplasmic reticulum aminopeptidase 2, S100-A9, insulin-like growth factor I, apolipoprotein (a), osteopontin, pregnancy zone protein, cartilage oligomeric matrix protein, CD44, and cadherin-related family member 2. Our analysis identified several proteins that shed further light on the distinctive pathogenesis of HA and could serve for biomarker research. However, these results need to be validated on a larger patient group.

Neutrophil-Dependent Immune Response Promotes Joint Damage in Hemophilia

Background: Hemophilic arthropathy (HA) is the predominant pathophysiology resulting from recurrent joint bleeding in individuals with hemophilia and leads to permanent joint damage, chronic pain and reduced quality of life. Although FVIII replacement therapy or FVIII mimetics like HEMLIBRA have significantly improved the disease outcome, joint bleeding continues to occur in severely hemophilic patients (FVIII<1%). HA starts at an early age and develops progressively over time, warranting the need for a therapy that can intervene the progression of HA. Unfortunately, such therapy does not exist and the etiological mechanism of HA remains poorly understood. Aim: To determine whether neutrophil Gasdermin-D (GSDMD)-dependent generation of neutrophil extracellular traps (NETs) in in the joint promotes HA. Methods: Knee joints in FVIII-total knockout (F8 TKO) or littermate WT male mice were injured using a needle . Scoring of the bleeding severity and histology of injured joints were conducted to assess the joint injury in mice.Imaging-flow-cytometry and ELISA assays were used to evaluate the number of circulating NETs in the blood samples of patients diagnosed with HA and mice with following knee injury. Neutrophils from HA patients, F8 TKO mice and matched controls were isolated, activation of GSDMD-pathway components was evaluated in neutrophils using qRT-PCR (gene expression) and western blotting (protein levels and cleavage). Results: F8 TKO but not control mice manifested unresolved joint injury and severe bleeding 5-days post knee injury. Circulating NETs (cNETs) and cNETs markers llike neutrophil elastase or citrulinated histones were significantly elevated in the plasma of hemophilia patients diagnosed with HA and injured F8 TKO mice but not plasma of control humans or injured WT mice or uninjured F8 TKO mice. Major genes (mRNA levels) associated with GSDMD-mediated NETs generation were significantly elevated in neutrophils of HA patients and injured F8 TKO mice compared to matched controls. Finally, western blot analysis revealed activation of GSDMD pathway in neutrophils isolated from HA patients and F8 TKO mice but not matched controls. Conclusions: These findings are the first to suggest that GSDMD-dependent generation of NETs contributes to the pathogenesis of HA

Scope Assisted Ankle Arthrodesis in a Young Male with Hemophilic Arthritis: A Case Study

Category:Ankle Arthritis; ArthroscopyIntroduction/Purpose:Arthritis is a debilitating condition that negatively affects an individual's ability to carry out activities of daily living. While osteoarthritis is a term many have become familiar with, as it is the most common form of arthritis encountered, hemophilic arthritis is a condition not frequently seen or discussed. Hemophilia is a congenital bleeding disorder caused by the absence or decrease of clotting factor VIII (Hemophilia A) or XI (Hemophilia B). When severe, this X-linked disease commonly results in intra-articular bleeding which, can progress to joint destruction1-4. This subsequently leads to the progressive destruction of articular cartilage and bone6-7.Methods:Arthroscopic assisted ankle arthrodesis with calcaneal autograft was performed. Calcaneal autograft was acquired through a small linear incision along the lateral wall of the calcaneus, a power graft harvester was introduced into the medullary bone to procure the graft. The left lower extremity was then placed into a non-invasive Gould Ankle distraction system and the standard anteromedial and anterolateral ankle scope portals were established. A scope and shaver were utilized to extensively debride all visualized hemorrhagic synovium. The shaver was then exchanged for a burr following debridement to remove the articular cartilage to both the talus and tibia. Following adequate preparation of the joint margins for fusion, the ankle joint was filled with the calcaneal autograft and rhPDGF-BB.Results:Various treatments have been described for patients suffering from hemophilic arthritis. While the use of clotting factor concentrations (CFCs) may reduce the risk of hemarthrosis, the risk of bleeding cannot be completely avoided2. Arthroscopic or open synovectomies has been described to remove the pathogenic synovium. Chemical or radioisotopic synoviorthesis is an option for less severe cases, but the treatment of choice is joint fusion or arthrodesis for advanced stages of arthropathy3.Conclusion:In patients with hemophilia, regular replacement therapy with clotting factor concentrates (prophylaxis) is effective in preventing recurrent bleeding episodes into joints and muscles. However, despite this success, intra-articular and intramuscular bleeding is still a major clinical manifestation of the disease. The pathogenesis of hemophilic arthropathy is multifactorial, with changes occurring in the synovium, bone, cartilage, and blood vessels. Our case report presents a unique pathology and the successful outcome that can be accomplished through surgical intervention and a multidisciplinary treatment approach.

The CXCL12/CXCR4 and VEGF165/Nrp1 Pathways Have Differential Effects on Pathological Neo-Angiogenesis and Vascular Remodeling in Hemophilic Arthropathy

Introduction: Joint hypervascularity is characteristic to hemophilic arthropathy (HA), which is a hallmark complication in patients with hemophilia. Angiogenesis in the hemophilic joint is triggered by bleeding and results in excessive vascular remodeling with enlarged irregularly shaped vessels that appear fragile, potentially causing re-bleeding. Therefore, targeting angiogenesis may offer novel treatment avenues in HA. Vascular endothelial growth factor A (VEGF-A) is an important angiogenic mediator implicated in the pathogenesis of HA, but a complete blockade may cause vascular instability with more bleeding, or inhibition of anti-angiogenic isoforms, thereby decreasing therapeutic efficacy. An alternative approach may be to target the co-receptor Neuropilin 1 (Nrp1) that facilitates binding of the pro-angiogenic isoform VEGF165 to its signaling receptor, VEGFR2. Here, we determine whether blocking the binding of VEGF165 to Nrp1 can curb the pathological vascular remodeling associated with hemophilic joint bleeding.Methods and results: Joint bleeding was induced by subpatellar needle puncture in FVIII-/- mice, resulting in pronounced intra- and peri-articular bleeding, evidenced by a drop in hematocrit from ~45% to 28 ± 10% 2 days after injury. The following antibody treatments were initiated 2 days after injury and were administered at 5 mg/kg, twice weekly for 4 weeks: B20-4 targeting murine VEGF-A, and YW107.4.87 blocking the VEGF165 binding site on Nrp1. The CXCR4 antagonist, AMD3100 (300 µg/day by subcutaneous osmotic pump) was included as positive control as it corrects hypervascularity induced by hemophilic joint bleeding (Wyseure et al . ISTH 2017).Four weeks after injury blood flow in the joint, measured by ultrasound-Power Doppler (PD), was increased 2.8-fold in injured vs uninjured FVIII-/- mice (p<0.001; n=13). Anti-VEGF treatment resulted in a similar 3.2-fold increase in PD signal (n=8), indicating that total inhibition of VEGF had no effect on the aberrant blood flow. Inhibition of Nrp1 had a partial effect (1.9-fold increase over baseline; p=0.16 vs no treatment; n=7), whereas inhibition of CXCL12-mediated vascular cell recruitment by the CXCR4 antagonist significantly blunted aberrant PD signals (p<0.05 vs no treatment; n=10). On histology, the total vessel count after anti-Nrp1 treatment was similar to no treatment and significantly greater than baseline (86 anti-Nrp1 vs 80 no treatment vs 42 baseline; p<0.01). Similarly, anti-Nrp1 treatment had no effect on the number of abnormally enlarged vessels (with a diameter ≥ 20 µm) compared to no treatment (15 anti-Nrp1 vs 13 no treatment vs 3 baseline; p<0.01 vs baseline). In contrast, with CXCR4 antagonist treatment both the total vessel count (64; p=0.3 vs baseline) and the number of abnormally enlarged vessels (7; p=0.1 vs baseline) remained low. However, anti-Nrp1 treatment did prevent the 2.5-fold increased perivascular expression of smooth muscle cell actin (αSMA; p<0.01) that typically accompanies the abnormally enlarged vessels in injured FVIII-/- mice. Thus, inhibition of Nrp1 lowered αSMA expression after hemophilic bleeding, similar to baseline and CXCR4 antagonist treatment, although it had no effects on vessel number and enlargement. This suggests that anti-Nrp1 treatment prevents the maturation during vascular remodeling in HA, potentially leaving the vessels destabilized and prone to vascular permeability. Towards that end, staining with Prussian Blue demonstrated increased hemosiderin deposits in anti-Nrp1 treated mice, similar to untreated injured FVIII-/- mice, whereas no signs of macroscopic joint bleeding or hemosiderin deposits were observed after treatment with the CXCR4 antagonist.Conclusions: Abrogating the VEGF165-Nrp1 interaction was not sufficient to prevent neo-angiogenesis and vessel lumen expansion in a murine hemophilic joint injury model. However, inhibition of Nrp1 did reduce perivascular remodeling that may allow regression of the aberrant vasculature over time, but also may promote further vessel instability and additional hemorrhaging. Thus, inhibition of the CXCL12/CXCR4 pathway affects neo-angiogenesis, whereas inhibition of the VEGF165/Nrp1 pathway predominantly affects perivascular maturation, but not neo-angiogenesis. These findings provide novel insights on the potential benefits and pitfalls of anti-angiogenic treatments in HA. Disclosuresvon Drygalski:Hematherix LLC: Membership on an entity's Board of Directors or advisory committees; Pfizer: Honoraria; Novo Nordisk: Honoraria; CSL Behring: Honoraria; Bioverativ: Honoraria; Bayer: Honoraria; Shire: Honoraria. Mosnier:Hematherix LLC: Membership on an entity's Board of Directors or advisory committees.

Neutrophil Extracellular Traps Promote Joint Injury in Hemophilia

Hemophilic arthropathy (HA) is the predominant pathophysiology resulting from recurrent joint bleeding in individuals with hemophilia. HA leads to permanent joint damage, chronic pain and reduced quality of life. Despite major advances in the treatment to prevent joint bleeding, HA continues to be a major morbidity affecting hemophilia patients and the etiological mechanism contributing to the progression of HA remains elusive. Recent evidence suggests that joint-bleeding may promote the release of erythrocyte and tissue-derived damage-associated-molecular-pattern molecules (DAMPs) that can trigger the sterile inflammation in the joints, however, the innate immune pathways contributing to the development of HA remain unclear. Here, we used a model of knee joint injury-induced HA in FVIII-total knockout (F8TKO) mice and blood samples from hemophilia patients diagnosed with HA. In vivo multi-photon-excitation (MPE) fluorescence imaging of injured synovial cavity in live F8TKO or control mice was used to assess NETs formation within joint capsule. Imaging-flow-cytometry and ELISA assays were used to evaluate the number of circulating NETs in patients diagnosed with HA and mice with knee-injury. Scoring of the bleeding severity, histology, IHC and confocal imaging of joints were conducted to assess the joint injury in mice. F8TKO but not control mice manifested knee-joint injury and severity of bleeding 5-days post knee-injury. Progression of knee-joint injury was associated with increased neutrophil accumulation and NETs shedding within the synovium of F8TKO mice. Circulating NETs were significantly abundant in the plasma of hemophilia patients diagnosed with HA and F8TKO following knee-injury but not plasma of control humans or mice. These findings are the first to suggest that NETs contribute to pathogenesis of HA in hemophilia. Currently, experiments are underway to identify the innate immune pathways that promote NETs shedding, leading to joint-damage in hemophilia. Disclosures Ragni: Alnylam/Sanofi, ATHN, BioMarin, Bioverativ, Sangamo, Spark: Research Funding; Alnylam/Sanofi, BioMarin, Bioverativ, Spark: Consultancy; BioMarin: Consultancy, Research Funding; Bioverativ: Consultancy, Research Funding; Spark: Consultancy, Research Funding; Takeda: Research Funding; Sangamo: Consultancy, Research Funding; Alnylam Pharmaceuticals Inc., Baxalta/Takeda, BioMarin, Bioverativ, and Spark Therapeutics: Membership on an entity's Board of Directors or advisory committees; American Thrombosis Hemostasis Network: Other: Committee work; Baxalta/Takeda, CSL Behring, Genentech, a member of the Roche Group, OPKO Biologics, and Vascular Medicine Institute: Research Funding.

EPCR deficiency or function-blocking antibody protects against joint bleeding–induced pathology in hemophilia mice

AbstractWe recently showed that clotting factor VIIa (FVIIa) binding to endothelial cell protein C receptor (EPCR) induces anti-inflammatory signaling and protects vascular barrier integrity. Inflammation and vascular permeability are thought to be major contributors to the development of hemophilic arthropathy following hemarthrosis. The present study was designed to investigate the potential influence of FVIIa interaction with EPCR in the pathogenesis of hemophilic arthropathy and its treatment with recombinant FVIIa (rFVIIa). For this, we first generated hemophilia A (FVIII−/−) mice lacking EPCR (EPCR−/−FVIII−/−) or overexpressing EPCR (EPCR++ FVIII−/−). Joint bleeding was induced in FVIII−/−, EPCR−/−FVIII−/−, and EPCR++FVIII−/− mice by needle puncture injury. Hemophilic synovitis was evaluated by monitoring joint bleeding, change in joint diameter, and histopathological analysis of joint tissue sections. EPCR deficiency in FVIII−/− mice significantly reduced the severity of hemophilic synovitis. EPCR deficiency attenuated the elaboration of interleukin-6, infiltration of macrophages, and neoangiogenesis in the synovium following hemarthrosis. A single dose of rFVIIa was sufficient to fully prevent the development of milder hemophilic synovitis in EPCR−/−FVIII−/− mice. The development of hemophilic arthropathy in EPCR-overexpressing FVIII−/− mice did not significantly differ from that of FVIII−/− mice, and 3 doses of rFVIIa partly protected against hemophilic synovitis in these mice. Consistent with the data that EPCR deficiency protects against developing hemophilic arthropathy, administration of a single dose of EPCR-blocking monoclonal antibodies markedly reduced hemophilic synovitis in FVIII−/− mice subjected to joint bleeding. The present data indicate that EPCR could be an attractive new target to prevent joint damage in hemophilia patients.

Pathophysiological Role of Synovitis in Hemophilic Arthropathy Development: A Two-Hit Hypothesis.

Despite an increasing access to prophylaxis with clotting factor concentrates, arthropathy still represents the main chronic complication of hemophilia. Whereas previous studies described hemophilic arthropathy (HA) as a degenerative arthropathy, somehow resembling osteoarthritis (OA), most recent evidence suggests that complex inflammatory and immunologic mechanisms are also involved in the pathophysiology of HA. In the present review, we described available data on major mechanisms leading to arthropathic changes in patients with hemophilia, with a specific focus on the role of synovium. The presence of hemosiderin in the joint space induces synovium proliferation, thus leading to formation of several lytic enzymes determining chondrocytes apoptosis and proteoglycans levels reduction. This leads to a direct joint “chemical” damage representing early damages in the pathogenesis of HA (first hit). In parallel, synovial membrane and synovial endothelial cells become a dynamic reservoir of inflammatory cells and mediators, and propagate the inflammatory response (second hit), switching the process from a chemical damage to an inflammatory damage. Overall, consistent data pointed out synovitis as the keystone in HA pathophysiology. This opens novel potential therapeutic targets in this clinical setting.

In vivo fluorescence molecular tomography of induced haemarthrosis in haemophilic mice: link between bleeding characteristics and development of bone pathology

BackgroundHaemophilic arthropathy is a chronic and debilitating joint disease caused by recurrent spontaneous joint bleeds in patients with haemophilia. Understanding how characteristics of individual joint bleeds relate to the subsequent development of arthropathy could improve management and prevention of this joint disease. Here, we aimed to explore relations between joint bleed characteristics and development of bone pathology in a mouse model of haemophilic arthropathy by using novel in vivo imaging methodology.MethodsWe characterised induced knee bleeds in a murine model of haemophilic arthropathy by quantitative in vivo fluorescence molecular tomography (FMT) and by measurements of changes in the diameter of the injured knee. Wild-type mice and non-injured haemophilic mice acted as controls. Development of arthropathy was characterised by post mortem evaluation of bone pathology by micro-CT 14 days after bleed-induction. In an in vitro study, we assessed the effect of blood on the quantification of fluorescent signal with FMT.ResultsIn most injured haemophilic mice, we observed significant loss of trabecular bone, and half of the mice developed pathological bone remodelling. Development of pathological bone remodelling was associated with significantly increased fluorescent signal and diameter of the injured knee just 1 day after induction of the bleed. Further, a correlation between the fluorescent signal 1 day after induction of the bleed and loss of trabecular bone reached borderline significance. In the in vitro study, we found that high concentrations of blood significantly decreased the fluorescent signal.ConclusionOur results add novel insights on the pathogenesis of haemophilic arthropathy and underline the importance of the acute phase of joint bleeds for the subsequent development of arthropathy.

Curcumin: hopeful treatment of hemophilic arthropathy via inhibition of inflammation and angiogenesis

ABSTRACTIntroduction: Hemophilic arthropathy (HA) is a serious complication among hemophilic patients causing a wide range of morbidity due to the inflammatory reactions followed by repeated episodes of bleeding. This condition has recently been shown to be accompanied by angiogenesis. The cascade starts with iron accumulation leading to an increase in CD68+ and CD11b+ cells responsible for initiating the inflammation.Areas covered: During inflammation, different factors and cytokines such as interleukin 1 (IL-1), IL-6, and tumor necrosis factor α (TNF-α) actively play parts in the pathogenesis of HA and also angiogenesis. It has been demonstrated that different pro-angiogenic and angiogenic factors such as hypoxia-inducible factor 1α (HIF-1α), vascular endothelial growth factor (VEGF), oxidative stress and matrix metalloproteinases (MMPs) are also important in the pathogenesis of HA. Curcumin is known for its strong anti-inflammatory and anti-angiogenic potentials. This agent is able to inhibit the mentioned inflammatory and angiogenic factors such as IL-1, IL-6, TNF-α, VEGF, MMPs, and HIF-1α. Also, as well as anti-angiogenic and anti-inflammatory activity, curcumin has a strong antioxidant potential and can decrease oxidative stress.Expert opinion: It seems that curcumin could be considered as a possible agent for the treatment of HA through inhibition of inflammation, oxidative stress, and angiogenesis.

Increased serum levels of progranulin (PGRN) in patients with haemophilic arthropathy.

Haemophilia A and B are rarely occurring X chromosome-linked congenital coagulation disorders dominated by spontaneous joint bleedings and chronic synovitis, leading to development of haemophilic arthropathy (HA). Progranulin (PGRN) is a growth factor with anti-inflammatory and immunomodulatory properties. PGRN is an important molecule in the pathogenesis of osteoarthritis (OA) and rheumatological disorders. This study was aimed at investigating the potential role of PGRN in the mechanisms underlying the pathogenesis of HA. The serum levels of PGRN were measured by enzyme-linked immunosorbent assay (ELISA) in patients with end-stage knee joint HA (n=20) and end-stage primary knee joint OA (n=20) who met the inclusion and exclusion criteria. The clinical and radiological assessment of disease severity was evaluated by the Knee Society Score (KSS) and Kellgren-Lawrence scale. Median PGRN levels in HA patients was 349.1ng/mL (232.8-415.6ng/mL) and in OA patients 148.3ng/mL (112.1-275.3ng/mL) with statistically significant differences between both groups (P<0.015). Further analysis revealed no correlation between PGRN levels and any of the patient demographics and clinical parameters. This study demonstrates increased PGRN serum levels in patients with HA and provides new insights into the mechanisms underlying the pathogenesis of HA indicating a new potential target for therapeutic intervention.

Rapid inflammation and early degeneration of bone and cartilage revealed in a time-course study of induced haemarthrosis in haemophilic rats.

Detailed knowledge of the sequential cell and tissue responses following haemarthrosis is important for a deep understanding of the pathological process initiated upon extensive bleeding into the joint causing haemophilic arthropathy (HA). The underlying pathobiology driving haemarthrosis towards HA has been difficult to establish in detail, although animal models have shed light on some processes. Previous studies have focused on a single or a few distant time points and often only characterizing one tissue type of the joint. The objective of this study was, therefore, to carefully map early onset of synovitis and HA following induced haemarthrosis. One hundred and thirty haemophilia A rats were subjected to induced haemarthrosis or a sham procedure in full anaesthesia and euthanized from 30 min to 7 days after the procedure. Pathological changes of the joints were visualized using micro-computed tomography, histology and immunohistochemistry. Synovitis developed within 24 h and was dominated by myeloid cell infiltrations. Cartilage and bone pathology were evident as early as 48-96 h after haemarthrosis, and the pathology rapidly progressed with extensive periosteal bone formation and formation of subchondral cysts. Fast, extensive and simultaneous cartilage and bone degeneration developed shortly after haemarthrosis, as shown by the detailed mapping of the early pathogenesis of HA. The almost immediate loss of cartilage and the pathological bone turnover suggest a direct influence of blood on these processes and are unlikely to be attributed simply to an indirect effect of inflammation.

Definition of pathogenetic variants of a hemophilic arthropathy by means of the functional assessment of microcirculation

Introduction. Better understanding of the pathogenesis of hemophilic arthropathy is crucial for prevention of irreversible injury to joints in patients with hemophilia. Research objective - to define a role of altered regulation of microcirculation in formation of joint injury in patients with hemophilia. Methods. The changes in knee and ankle joints in 82 patients with hemophilia were investigated by means of ultrasound and X-ray. Microcirculation was evaluated using computer infrared thermography and laser doppler flowmetry in joints of 44 patients and 46 healthy individuals. Results. Increased temperature and perfusion (M) are major risk factors of hemarthrosis development (RR=1.86 and RR=1.26) and are characteristic of joints with hemorrhages developing more often than 1 time per month. Increase in these indexes in joints without hemarthrosis in the anamnesis is a sign of a latent inflammation. Both decrease in the index of shunting (IS) and increase in a vibration amplitude of perfusion in the endothelial range (Amax E) are characteristic of joints with a recurrence of hemarthrosis more often than 3 times a month. Decrease in indexes of M and Amax E with concomitant increase in PSh demonstrate low risk of hemarthrosis. Conclusions. Changes of microcirculation in joints represent an important factor in the pathogenesis of hemophilic arthropathy development in the patients with variable risk of a recurrence of a hemarthrosis. Joint inflammation leads to endothelial dysfunction with poor vasospasm, to increase in Amax E and M that is a new diagnostic sign of a latent inflammation in joints. Decrease of PSh promotes recurrence of hemarthrosis because of strengthening of an imbuing of tissues of joint blood. Preservation of endothelium-mediated vasoconstriction, decrease in the neurogenic tone, increase in shunting of blood are characteristic features of hemophilic arthropathy in patients with infrequent recurrence of hemarthrosis.

Defective TAFI Activation in Hemophilia Exacerbates Vascular Remodeling in Hemophilic Arthropathy

Introduction: Patients with hemophilia A or B develop hemophilic arthropathy (HA), characterized by inflammation, cell proliferation, and hypervascularity in the synovial joint tissue. The hypervascular response in HA results in aberrant vascular remodeling and the formation of enlarged, irregularly shaped and leaky vessels, which are prone to bleeding. Recently, we showed that after a single joint bleed in FVIII-/- mice changes in soft tissue proliferation, neo-angiogenesis, and cartilage destruction were reversible, whereas vascular remodeling in the joint became progressively worse over time (Bhat et al. 2015). Activated thrombin activatable fibrinolysis inhibitor (TAFIa) conveys anti-fibrinolytic and anti-inflammatory functions by removal of C-terminal (CT) Lys or Arg residues from fibrin and pro-inflammatory mediators, such as C3a, C5a, bradykinin, and thrombin-cleaved osteopontin that may be relevant to HA. Because the activation of TAFI is defective in hemophilia, we determined whether TAFI deficiency contributes to aberrant vascular remodeling in HA using a mouse knee injury model.Methods and Results: Joint bleeding was induced by a subpatellar needle puncture in WT and TAFI-/- mice after a single injection of a FVIII inhibiting antibody to evoke sufficient joint bleeding. Inhibitor-treated TAFI-/- mice bled to the same extent as FVIII-/- mice, however inhibitor-treated WT mice bled minimally. Combining both inhibitory anti-TAFI and anti-FVIII antibodies resulted in bleeding in WT mice comparable to that in FVIII-/- and inhibitor-treated TAFI-/-mice as indicated by decreased hematocrits 2 days post injury (27±9%, 28±10%, 24±7%) and a 4-fold impaired weight-bearing of the injured hind leg. The inhibitors were cleared after 4 days permitting analyses of TAFI-specific effects on long-term vascular remodeling after joint bleeding.At week 2 post injury, all mice showed evidence of increased vascularity in the injured joint. Power Doppler Ultrasound (PD) signals, indicating flow in the joint, were increased 3.5-fold in FVIII-/-, TAFI-/- and WT mice. Accordingly, Safranin O-Fast Green analysis indicated induction of neoangiogenesis as mean vessel count increased from 40 at baseline to 101, 119 and 71 in FVIII-/-, TAFI-/- and WT mice, respectively. At week 4 post injury, however, WT mice diverged from FVIII-/- and TAFI-/- mice. PD signals of FVIII-/- and TAFI-/- mice remained high (3.5-fold increase over baseline, p< 0.001), whereas those of WT mice were significantly reduced compared to week 2 (p< 0.05). Persistent vascular remodeling occurred in FVIII-/- and TAFI-/- mice, but not in WT mice. While total vessel counts decreased in all mice, the percentage of vessels ≥ 20 µm, considered the upper limit of normal vessel diameter in the joint, was increased 2-fold in FVIII-/- and TAFI-/- mice (p< 0.001) but was similar to baseline (11%) in WT mice. Similarly, a 2-fold increase of αSMA expression in the medial meniscal area in TAFI-/-mice support ongoing vascular remodeling in these mice (p< 0.01). Thus, the impaired TAFI function in HA promotes vascular remodeling.In search of proangiogenic mediators implicated in the pathogenesis of HA and susceptible to inactivation by TAFIa, we identified stromal cell-derived factor 1α (SDF1α; CXCL12), a well-known endothelial progenitor recruitment factor. SDF1α contains a functionally requisite CT Lys that is needed for CXCR4 activation. Histological analysis using a CT-Lys-specific anti-SDF1α revealed pronounced expression of intact SDF1α on the joint vessels in TAFI-/- mice at week 4 post injury. In vitro,TAFIa rapidly cleaved the CT-Lys of SDF1α as determined by a CT-Lys specific W-blot and ELISA. In addition, TAFIa-treated SDF1α failed to induce migration of endothelial cells in a transwell cell migration assay.Conclusion: Vascular remodeling after joint bleeding was perpetuated in TAFI-/- mice to the same extent as in FVIII-/- mice. Based on the identification of SDF1α as a novel substrate for TAFIa, we propose that the defective activation of TAFI in hemophilia results in impaired inactivation of SDF1α, allowing functional SDF1α to accumulate on synovial vessels in the injured joint thereby exacerbating the recruitment of endothelial progenitor cells to the joint. This in combination with the ongoing angiogenesis in the joint ultimately results in irreversible vascular remodeling that underlies the development of HA. Disclosuresvon Drygalski:Baxalta/Shire: Consultancy, Honoraria, Speakers Bureau; Bayer: Consultancy, Honoraria, Speakers Bureau; Biogen: Consultancy, Honoraria, Speakers Bureau; CSL-Behring: Consultancy, Honoraria, Speakers Bureau; Novo Nordisk: Consultancy, Honoraria, Speakers Bureau; Pfizer: Consultancy, Honoraria, Speakers Bureau; Hematherix LLC: Membership on an entity’s Board of Directors or advisory committees. Mosnier:Hematherix LLC: Membership on an entity’s Board of Directors or advisory committees; The Scripps Research Institute: Patents & Royalties; Bayer: Honoraria, Speakers Bureau; Baxalta: Honoraria, Speakers Bureau.

The Role of Angiogenesis in Haemophilic Arthropathy: Where Do We Stand and Where Are We Going?

Haemophilia is an inherited bleeding disorder that can lead to degenerative joint arthropathy due to recurrent bleeding episodes affecting the musculoskeletal system of the patient. The cause of bleeding can be either traumatic or spontaneous. The pathogenesis of haemophilic arthropathy is unclear as many factors like iron, inflammatory cytokines, and angiogenic factors contribute to this process. Blood into joints can deteriorate the bone to such an extent that the patient experiences pain, reduction of the range of movement, and deformity of the joint, conditions that could have a great impact on quality of life. Over the years, management of haemophilic arthropathy has changed. Nowadays, early diagnosis with high resolution imaging like magnetic resonance imaging along with application of prophylaxis regimens can reduce the extent of damage to the joints. However, not all haemophilia patients have access to these interventions as cost may be prohibitive for some of them. The need for new, easy, and cost-effective strategies with the ability to identify early changes could be beneficial and could make a difference in the management of haemophilic arthropathy. Understanding the mechanism of processes like angiogenesis in the mechanism of developing arthropathy could be innovative for these patients and could help in the detection of new early diagnostic and therapeutic markers.

Blood-induced arthropathy in hemophilia: mechanisms and heterogeneity.

Hemophilia A is an X-linked bleeding disorder that can be largely controlled by treatment with recombinant factor VIII. However, this treatment is only partially effective in preventing hemophilic arthropathy (HA), a debilitating degenerative joint disease that is caused by intra-articular bleeding events. The disease progression of HA has several distinct steps, beginning with hemophilic synovitis (HS), a hyperplasia of the synovial lining coupled with a neovascular response, followed by joint erosion with cartilage destruction and erosion of the underlying bone. The early stages of HA have certain features in common with arthritides such as rheumatoid arthritis (RA), whereas the later degenerative stages of HA have some similarities with osteoarthritis (OA). The main purpose of this review is to explore the similarities between HA with RA and OA and discuss how this information could potentially help understand the pathogenesis of HA and uncover new treatment opportunities.

Serum Cartilage Oligometric Matrix Protein and Pettersson Scoring System As an Index for Hemophilic Arthropathy

▪The pathogenesis of hemophilic arthropathy is multifactorial, with changes occurring in the synovium, bone, cartilage, and blood vessels. Recurrent joint bleeding causes synovial proliferation and inflammation (hemophilic synovitis) that contributes to end stage degeneration (hemophilic arthropathy); with pain and limitation of motion that severely affects patients’ quality of life.The aim of the present study was to evaluate the degree of joint damage in boys with hemophilia using plain x-ray, and to measure serum level of human cartilage oligomeric matrix protein, to determine its relation to the degree of joint damage.The study was carried out on thirty boys with hemophilic arthropathy (group I) and ten healthy boys were included as control (group II).All hemophilic patients were scored for Functional independence score (FISH score) in hemophilia and radiological changes (Pettersson’s score) using conventional frontal and lateral radiographs of the most affected joint.Factor activity level was measured for all hemophilic patients while serum cartilage oligomeric matrix protein (COMP) was measured for hemophilic patients and control group.Among the thirty hemophilic patients, 26 (86.7%) patients were hemophilia A and 4 (13.3%) patients were hemophilia BAll patients were receiving on demand replacement therapy using plasma derived Factor concentrate or fresh frozen plasma (FFP) according to availability.Fifteen patients (50%) had severe hemophilia, 7 (23.3%) had moderate and 8(26.72%) had mild hemophilia.A higher serum level of COMP with a mean of 757± 211.30 in the severe hemophiliacs, and a mean of 403.57 ± 86.49 and 211.25 ± 74.26 in the moderate and mild hemophiliacs respectively the difference was statistically significant (p < 0.001).Serum level of COMP in group I was significantly higher than in group II (p=0.004) with significant negative correlation with FISH score (r=-0.435 p=0.016). COMP correlated positively with joint space narrowing of the Pettersson score (r=0.421 p<0.001) and with total Pettersson score (r=0.421 p=0.020).The number of joints affected (during life) of hemophilic patients ranged between 1-12 with a mean of 5.50 ± 2.46 Joints. A significant positive correlation between serum level of COMP and number of joints affected (r = 0.487, p = 0.006).Joint space narrowing is the most important indicator of cartilage loss. Serum COMP level is indicative of the amount of joint damage in patients with hemophilic arthropathy.The combined scoring of functional independence and Pettersson in addition with serum levels of COMP give a good overview of the degree of hemophilic arthropathy DisclosuresNo relevant conflicts of interest to declare.

Guidelines of management of musculoskeletal complications of hemophilia

Hemophilia is an X-linked heritable coagulopathy with an overall prevalence of approximately 1 in 10,000 individuals. The most common form is factor VIII deficiency (hemophilia A), which comprises approximately 80% of cases. Factor IX deficiency (hemophilia B), comprises approximately 20% of cases. In patients with hemophilia, regular replacement therapy with clotting factor concentrates (prophylaxis) is effective in preventing recurrent bleeding episodes into joints and muscles. However, despite this success, intra-articular and intramuscular bleeding is still a major clinical manifestation of the disease. Bleeding most commonly occurs in the knees, elbows, and ankles, and is often evident from early childhood. The pathogenesis of hemophilic arthropathy is multifactorial, with changes occurring in the synovium, bone, cartilage and blood vessels. Recurrent joint bleeding causes synovial proliferation and inflammation (hemophilic synovitis) that contribute to end-stage degeneration (hemophilic arthropathy); with pain and limitation of motion severely affecting patients' quality of life. The author conducted a comprehensive review and synthesis of the relevant literature. The author reviewed all compiled reports from computerized searches. Searches were limited to English-language sources and human subjects. Literature citations were generally restricted to published manuscripts appearing in journals listed in Index Medicus and reflected literature published up to July 1, 2013. The aim of this updated paper is to provide comprehensive and timely evidence-based guidelines and recommendations on the treatments of damaged joint among hemophilia patient. Further recommendations included the control of risk factors, interventional approaches for treatment of hemophilia, the use of bypassing factors for the inhibitors, and preventing recurrent bleeding especially in high-risk populations are provided. Prophylaxis by replacement of the missing factor in patients with hemophilia is the optimal way to prevent the occurrence of haemarthrosis and thereby the onset of arthropathy, provided that it is started early in life. Dosing should be individualized and increased in case of bleeding. Prevention of bleeding episodes through early treatment will prevent accumulation of blood in joint and the subsequent inflammation and potential hemophilic arthropathy. Treatment must be maintained until bleeding remission and patients have recovered as much of their ROM and muscular strength as possible. Clinical evaluation of the joints, gait, motion, muscle tone, functional level of disability, pain, and swelling, as well as imaging techniques, must be performed to assist in the diagnosis of chronic synovitis and to guide treatment decisions. The first step to treating synovitis, refractory to medical treatment, is the use of synovectomies, non-surgical or surgical interventions. In many cases, joint deformities have to be treated by open orthopaedic surgery. State-of-the-art treatment of patients with hemophilia requires a multidisciplinary team. Level of evidence: Level III (Systematic Literature review).

Haemophilia-associated Yersinia pseudotuberculosis serotype O:1 septicaemia: the role of iron

Septicaemia and septic arthritis due to Yersinia pseudotuberculosis are rare diseases with high mortality rates. Reactive arthritis caused by Yersinia infection is a well-known complication but septic arthritis is found at a much lower frequency. It has already been established that there is a relationship between yersiniosis and iron but there are currently no data about yersiniosis and haematological disorders such as haemophilia. We report a case of septic arthritis due to Y. pseudotuberculosis as an early manifestation of Yersinia septicaemia in a patient with severe haemophilia A. The patient had no history of immunosuppression and presented with a repeat case of haemarthrosis with a fever of unknown origin. Furthermore, he suffered from acute-on-chronic renal failure and non-ST segment elevation myocardial infarction. Arthrocentesis and blood culture tested positive for Y. pseudotuberculosis. Iron deposits at localized sites in the synovium in patients with haemophilia have been described, and as Yersinia infections are common in patients with secondary iron overload, we felt that a review of the literature was in order. Severe Yersinia infection is often associated with iron overload, a condition that might occur as a side effect in the treatment of haemophilia. Iron overload, which plays an important role in the pathogenesis of haemophilic arthropathy, may have increased the virulence of Y. pseudotuberculosis in the present case.

Haemophilia and joint disease: pathophysiology, evaluation, and management.

In patients with haemophilia, regular replacement therapy with clotting factor concentrates (prophylaxis) is effective in preventing recurrent bleeding episodes into joints and muscles. However, despite this success, intra-articular and intramuscular bleeding is still a major clinical manifestation of the disease. Bleeding most commonly occurs in the knees, elbows, and ankles, and is often evident from early childhood. The pathogenesis of haemophilic arthropathy is multifactorial, with changes occurring in the synovium, bone, cartilage, and blood vessels. Recurrent joint bleeding causes synovial proliferation and inflammation (haemophilic synovitis) that contribute to end-stage degeneration (haemophilic arthropathy); with pain and limitation of motion severely affecting patients' quality of life. If joint bleeding is not treated adequately, it tends to recur, resulting in a vicious cycle that must be broken to prevent the development of chronic synovitis and degenerative arthritis. Effective prevention and management of haemophilic arthropathy includes the use of early, aggressive prophylaxis with factor replacement therapies, as well as elective procedures, including restorative physical therapy, analgesia, aspiration, synovectomy, and orthopaedic surgery. Optimal treatment of patients with haemophilia requires a multidisciplinary team comprising a haematologist, physiotherapist, orthopaedic practitioner, rehabilitation physician, occupational therapist, psychologist, social workers, and nurses. Journal of Comorbidity 2011;1:51-59.