Pathogenesis of hemophilic arthropathy

Extravascular factor IX pool fed by prophylaxis is a true hemostatic barrier against bleeding

BACKGROUND

Factor (F)IX can bind to type IV collagen in the endothelial basement membrane and diffuse into extravascular spaces. Previous studies in rodents have reported a large biodistribution of FIX.

OBJECTIVES

The aim of the study was to evaluate the potential hemostatic activity of extravascular FIX and its role in protecting against joint bleeds.

METHODS

The capacity of 4 different FIX molecules (plasma-derived and recombinant) to bind type I and type IV collagen was studied here. FIX molecules were also administered intravenously at doses of 50 to 3000 IU/kg in FIX knockout mice.

RESULTS

A specific FIX signal was detected in immunohistochemistry in the liver as well as in muscles and knee joints with recombinant FIX molecules injected at 1000 and 3000 IU/kg but not at the usual clinical doses of 50 to 100 IU/kg, while plasma-derived FIX generated a FIX signal at all doses, including 50 IU/kg. Such a signal was also detected after five 100 IU/kg daily infusions of recombinant FIX, suggesting that FIX can accumulate in the extravascular space during prophylaxis. The extravascular procoagulant activity of FIX, assessed in saphenous vein bleeding assays, was significantly higher in hemophilia B mice after these 5 days of prophylaxis compared to a single infusion of 100 IU/kg of FIX and assessment of FIX activity 7 days later.

CONCLUSION

Taken together, these results show that in individuals with severe hemophilia B receiving regular prophylaxis with FIX, extravascular accumulation of FIX over time may have a significant impact on the coagulation capacity and protection toward bleeding.

Iron overload causes macrophages to produce a pro-inflammatory phenotype in the synovium of hemophiliac arthritis via the acetyl-p53 pathway

AIM

Haemophiliac arthritis (HA) is caused by spontaneous intra-articular hemorrhage and repeated intra-articular hematomas, leading to iron overload, which, in turn, induces M1 macrophage polarisation and inflammatory cytokine secretion, resulting in synovitis. Here, we explored the mechanism by which iron overload in HA induces the polarisation of M1 macrophages, providing a new approach for the treatment of HA synovitis.

METHODS

The synovium from the knee joints of normal amputees and patients with HA was collected. Pathological changes in the synovial tissues were analysed using hematoxylin and eosin staining. Iron tissue deposition was evaluated using the iron assay kit and Prussia Blue staining, while macrophage phenotype was determined using immunofluorescence. The levels of pro-inflammatory cytokines and p53 acetylation were determine using western blotting. An in vitro iron overload model was established by inducing THP-1 macrophages with ferric ammonium citrate, and the involvement of acetylated p53 in M1 macrophage polarisation was investigated.

RESULTS

Compared to control samples, the iron content in the synovium of patients with HA was significantly increased. The protein levels of M1 macrophage markers, pro-inflammatory cytokines, and acetylated p53, were also significantly elevated in the synovial tissues of patients with HA. Similar results were observed in the in vitro iron overload model. Furthermore, the inhibition of p53 acetylation in vitro reversed these iron overload-induced effects.

CONCLUSION

In patients with HA, iron overload induced synovial p53 acetylation, leading to macrophage polarisation toward the M1 phenotype and increased inflammatory cytokine secretion, resulting in synovitis.

HIGHLIGHTS

Synovial iron overload is associated with changes in P53 acetylation in hemophiliac arthritis (HA). Acetylated p53, a known regulator of macrophage polarization, is highly expressed in HA synovium, suggesting a potential role in M1 polarization. HA synovial macrophages predominantly polarize into the pro-inflammatory M1 phenotype, secreting elevated levels of pro-inflammatory cytokines.

Ultrasound evaluation of hemophilic arthropathy: a proposal of definitions in a changing landscape

The advent of novel effective treatments and the identification of the need to achieve a higher trough level for persons with hemophilia A and B have changed the landscape of management of these patients, allowing to change the target from survival and prevention of life-threatening complications to prevention of musculoskeletal complications and improvement of quality of life. Point-of-care musculoskeletal ultrasound imaging has also improved the early recognition of joint bleeding and the differential diagnosis of acute joint pain. In addition, joint ultrasound allows the evaluation of the severity of hemophilic arthropathy in terms of synovitis and cartilage and bone damage. However, a lack of standardization in the definition of ultrasound elementary lesions of hemophilic arthropathy may lead to confusion and an incorrect evaluation of the presence and progression of joint damage. Here, we propose to start a standardization and validation process for ultrasound definitions of hemophilic arthropathy that has been planned to become a project within the Factor VIII/IX Standardization Subcommittee of the International Society on Thrombosis and Haemostasis Scientific and Standardization Committee.

Blood-Induced Arthropathy: A Major Disabling Complication of Haemophilia

Haemophilic arthropathy (HA) is one of the most serious complications of haemophilia. It starts with joint bleeding, leading to synovitis which, in turn, can cause damage to the cartilage and subchondral bone, eventually inducing degenerative joint disease. Despite significant improvements in haemophilia treatment over the past two decades and recent guidelines from ISTH and WFH recommending FVIII trough levels of at least 3 IU/dL during prophylaxis, patients with haemophilia still develop joint disease. The pathophysiology of HA is complex, involving both inflammatory and degenerative components. Early diagnosis is key for proper management. Imaging can detect joint subclinical changes and influence prophylaxis. Magnetic resonance imagining (MRI) and ultrasound are the most frequently used methods in comprehensive haemophilia care centres. Biomarkers of joint health have been proposed to determine osteochondral joint deterioration, but none of these biomarkers has been validated or used in clinical practice. Early prophylaxis is key in all severe haemophilia patients to prevent arthropathy. Treatment is essentially based on prophylaxis intensification and chronic joint pain management. However, there remain significant gaps in the knowledge of the mechanisms responsible for HA and prognosis-influencing factors. Better understanding in this area could produce more effective interventions likely to ultimately prevent or attenuate the development of HA.

Decline in health-related quality of life and foot and ankle patient reported outcomes measures in patients with haemophilia and ankle haemarthropathy

BACKGROUND

Haemophilia is an X-linked recessive genetic disorder characterised by bleeding within soft tissue and joints. The ankle is disproportionally affected by haemarthropathy when compared to the elbows and knees; reported as the most affected joints in patients with haemophilia. Despite advances in treatment, patients still report ongoing pain and disability, however, the impact has not been evaluated, nor has the effect on health-related quality of life (HRQoL) or foot and ankle patient-reported outcome measures (PROMs). The primary aim of this study was to establish the impact of ankle haemarthropathy in patients with severe and moderate haemophilia A and B. Secondly to identify the clinical outcomes associated with a decline in HRQoL and foot and ankle PROMs.

METHODS

A cross-sectional multi-centre questionnaire study was conducted across 18 haemophilia centres in England, Scotland and Wales with a recruitment target of 245 participants. The HAEMO-QoL-A and Manchester-Oxford Foot Questionnaire (MOXFQ) (foot and ankle) with total and domain scores measured impact on HRQOL and foot and ankle outcomes. Demographics, clinical characteristics, ankle haemophilia joint health scores, multi-joint haemarthropathy and Numerical Pain Rating Scales (NPRS) of "ankle pain over the past six months" were collected as a measure of chronic ankle pain.

RESULTS

A total of 243 of 250 participants provided complete data. HAEMO-QoL-A and MOXFQ (foot and ankle) total and index scores indicated worse HRQoL with total scores ranging from a mean of 35.3 to 35.8 (100 best-health) and 50.5 to 45.8 (0 best-health) respectively. NPRS (mean (SD)) ranged from 5.0 (2.6) to 5.5 (2.5), with median (IQR) ankle haemophilia joint health score of 4.5 (1 to 12.5) to 6.0 (3.0 to 10.0) indicating moderate to severe levels of ankle haemarthropathy. Ankle NPRS over six months and inhibitor status were associated with decline in outcome.

CONCLUSIONS

HRQoL and foot and ankle PROMs were poor in participants with moderate to severe levels of ankle haemarthropathy. Pain was a major driver for decline in HRQoL and foot and ankle PROMs and use of NPRS has the potential to predict worsening HRQoL and PROMs at the ankle and other affected joints.

18 F-FDG PET/CT imaging for haemophilic arthropathy compared with clinical, radiological and power Doppler sonographic characteristics of 20 haemophilia patients

INTRODUCTION AND OBJECTIVES

Repeated joint bleeding in haemophilia patients may lead to haemophilic arthropathy with marked inflammation and synovitis. This study investigated the potential of ¹⁸ F-fluorodeoxyglucose positron emission tomography-computed tomography (¹⁸ F-FDG PET/CT) as a novel diagnostic method for haemophilic arthropathy.

MATERIALS AND METHODS

We recruited 20 adult haemophilia patients who reported history of hemarthroses in the shoulder, elbow, hip, knee, or ankle joints. All joints were assessed by power Doppler ultrasonography and radiography, and graded by hyperaemia score and Pettersson score, respectively. Joint pain was evaluated by visual analogue score (VAS). Range of motion (ROM), Haemophilia Joint Health Score (HJHS) and annual joint bleeding rate (AJBR) were recorded. Finally, all participants had whole-body ¹⁸ F-FDG PET/CT, and maximum standardized uptake value (SUVmax) of the joints being studied was measured.

RESULTS

Thirteen patients had severe haemophilia, and seven had moderate haemophilia. The mean age was 36 years. PET SUVmax showed significant correlations with VAS, ROM, Pettersson score, hyperaemia score, HJHS score and AJBR in all large joints except hip. Joints with pain, hyperaemia and radiographic changes were found to have higher SUVmax than those without these features. Using Youden's index, the optimal cut-off value for early radiographical arthropathy was found to be between 1.9 and 2.0.

CONCLUSION

Our study indicates that ¹⁸ F-FDG PET/CT imaging correlated well with various conventional diagnostic techniques. It also demonstrated high sensitivity and specificity for early radiographic arthropathy. ¹⁸ F-FDG PET/CT imaging may quantitatively evaluate disease activity of most large joints in a single examination and help detect early haemophilic arthropathy.

The impact of ankle haemarthropathy in patients with moderate haemophilia

INTRODUCTION

Moderate haemophilia has traditionally been associated with less complications than severe haemophilia. Changes in treatment recommendations have highlighted the burden of moderate haemophilia with a subset of patients with a severe bleeding phenotype. The ankle joint is disproportionally affected by ankle haemarthropathy however the impact has not been evaluated in moderate haemophilia, nor the effect on health related quality of life (HRQoL) or foot and ankle outcomes.

AIMS

To establish the impact of ankle haemarthropathy in patients with moderate haemophilia.

METHODS

A multicentre questionnaire study recruited patients from 11 haemophilia centres in England, Scotland and Wales. The HAEMO-QoL-A and Manchester-Oxford foot and ankle questionnaire (MOXFQ) with total and domain scores measured impact. Measures of pain and ankle haemophilia joint health (HJHS) scores were also collected.

RESULTS

Twenty-nine participants were recruited. HAEMO-QoL A mean (SD) total scores of 10.8 (5.2) of 100 (best health) and foot and ankle specific MOXFQ total scores of 45.5 (24.7) above zero (best outcome) indicate poor HRQoL and foot and ankle outcomes. Average ankle pain over past 6 months of (0-10) 5.5 (SD2.5) was reported and median (IQR) ankle HJHS of 3.0 (1;12.5) to 4.5 (0;9.5) for the left and right ankles.

CONCLUSION

HRQoL and foot and ankle specific outcomes are poor in patients with moderate haemophilia and ankle haemarthropathy, driven by chronic levels of ankle joint pain. Despite moderate haemophilia being considered less affected by haemarthrosis and haemarthropathy, patients with a bleeding or haemarthropathy phenotype are clinically similar to patients with severe haemophilia A.

Intra-articular injection of platelet-rich plasma in patients with hemophilia and painful knee joint cartilage degeneration

INTRODUCTION

Knee arthropathy causes pain to people with hemophilia (PWH). One of the current controversies is whether injections of intra-articular platelet-rich plasma (PRP) are effective in relieving the knee pain of PWH.

AREAS COVERED

A narrative literature review was conducted on the efficacy of PRP injections in the knees of PWH.

EXPERT OPINION

Intra-articular PRP knee injections are widely used in patients with knee osteoarthritis to relieve pain and delay total knee arthroplasty. Although numerous publications have supported the use of PRP in knee osteoarthritis, there is still major controversy regarding its true usefulness, given that a number of studies with a high degree of evidence have failed to show the efficacy of PRP. With respect to painful hemophilic arthropathy, the use of PRP injections is even more controversial, as there are only four publications on the subject supporting the use of PRP in hemophilia, all of them with a low degree of evidence. A publication with grade 1 evidence recommended against the use of PRP in hemophilic arthropathy because its efficacy has not been demonstrated. My opinion is that intra-articular PRP injections should not be used in hemophilia until there is more evidence of its benefits.

The Profile of Markers of Bone Turnover, Inflammation and Extracellular Neutrophil Traps on Bone Mass in Haemophilia and the Development of Haemophilic Arthropathy

Background: The aim of the study is to evaluate selected biomarkers of bone turnover, inflammation, neutrophil trap and factors predisposing haemophiliacs to bone loss, and to analyse their relationship with clinical features, treatment and complications. Methods: The levels of interleukin 6 (IL-6); citrullinated histone (CH3); osteocalcin (BGLAP); bone alkaline phosphatase (BALP); N-terminal procollagen type I propeptide (P1NP); and C-terminal collagen type I telopeptide (C1CP) were examined in 60 patients with haemophilia. Results: The cut-off value for BGLAP is 26.41 ng/mL, and 929.7 pg/mL for CH3. There is a statistically significant difference between BGLAP, BALP, C1CP and CH3 concentrations, depending on the prophylaxis used. The median concentration of BGLAP in patients taking the factor on demand is 28.0 ng/mL, BALP 322.5 U/L, C1CP 191.2 ng/mL and CH3 1114.4 pg/mL. In patients taking recombinant coagulation factor VIII/IX as prophylaxis of bleeding, the median BGLAP concentrations are 35.9 ng/mL, BALP 280.9 U/L, C1CP 161.6 ng/mL and CH3 952.5 pg/mL. BGLAP and BALP concentrations are dependent on the development of haemophilic arthropathic. Conclusions: The concentrations of selected markers of bone turnover and NETs may help to identify patients at particular risk of developing haemophilic arthropathy and bone metabolic turnover abnormalities.

How much preoperative flexion contracture is a predictor for residual flexion contracture after total knee arthroplasty in hemophilic arthropathy and rheumatoid arthritis?

Background

Although total knee arthroplasty (TKA) in hemophilic arthropathy (HA) or rheumatoid arthritis (RA) can improve functional ability, the postoperative range of motion (ROM) and prosthesis durability are reduced compared with those in osteoarthritic patients.

Aim

We aimed to compare (1) the pre- and postoperative flexion contracture after TKA in HA and RA, (2) the threshold of preoperative flexion contracture as a predictor of residual contracture > 15° after TKA, and (3) the survival rate.

Methods

Data from a consecutive cohort comprising 48 TKAs in HA and 92 TKAs in RA were retrospectively reviewed. The degree of flexion contracture was analyzed. Through receiver operating characteristics analysis, we aimed to determine the cutoff value of preoperative flexion contracture that increases the risk of residual contracture > 15° after TKA and compare the cutoff value in HA and RA. The survival rate was evaluated based on life table analysis and the Kaplan–Meier method.

Results

The degree of preoperative flexion contracture was not significantly different. The degree of postoperative residual flexion contracture was 5.6° in the HA group and 1.4° in the RA group, respectively (p < 0.001). The cutoff value of preoperative flexion contracture for residual contracture of > 15° at last-follow up was 25.0° in the HA group and 32.5° in the RA group. The 5- and 12-year survival rates were 96% and 87% in the HA and 99% and 95% in the RA group, respectively (n.s.).

Conclusions

The postoperative residual flexion contracture was greater and the cutoff value of preoperative flexion contracture for residual contracture was smaller in the HA group than the RA group. Appropriate intra- and postoperative care to avoid postoperative residual contracture is required in HA patients.

Level of evidence

III.

Inflammation, angiogenesis and sensory nerve sprouting in the synovium of bony ankylosed and not bony ankylosed knees with end-stage haemophilic arthropathy

INTRODUCTION

Clinical practice showed that patients with haemophilia (PwH) with bony ankylosed end-stage haemophilic arthropathy knees reported milder pain than those with not bony ankylosed knees.

AIM

To compare the differences in pain sensation and the histopathological differences in synovial samples of affected knee joints between PwH with bony ankylosed end-stage haemophilic arthropathy knees and those with not bony ankylosed knees.

METHODS

From January 2011 to December 2019, the synovial samples of knee joints were collected during total knee arthroplasty (TKA) surgery for end-stage haemophilic arthropathy. The visual analogue scale (VAS, 0-10) pain score was reviewed from the chart data of the patients. The thickness of the inner layer of the synovium in haematoxylin and eosin (H&E) staining sections was measured. The expression levels of Ki67, IL-1β, TNF-α, CD31, VEGF, NGF and PGP9.5 in the synovium were detected by immunohistochemistry (IHC) method.

RESULTS

Fifty-two end-stage haemophilic arthropathy knee synovial samples from 36 male PwH (34 type A and 2 type B) were collected. Fifteen knees had bony ankylosed (BA-group), and 37 were not bony ankylosed (Not-BA-group). The mean age of patients at TKA surgery of BA-group and Not-BA-group was 32 years (15) and 32 years (10), respectively (p = 0.824). Before TKA surgery, the mean VAS pain scores of patients in the Not-BA-group were significantly higher than those in the BA-group (p < 0.001). The mean thickness of the inner layer of the synovium, the mean rate of Ki67+ cells, the mean density of CD31+ vascular endothelial cells and the expression levels of IL-1β, TNF-α, VEGF and NGF in samples in the Not-BA-group was significantly higher than those in samples in the BA-group (p < 0.001, p = 0.02, p = 0.001, p = 0.117, p < 0.001, p = 0.003 and p = 0.008), respectively. The mean density of PGP9.5+ sensory neural fibres in the Not-BA-group was slightly higher than in the BA-group (p = 0.131). Linear regression analysis showed a significant positive correlation between the VAS pain score and indicators including the synovial thickness, the rate of Ki67+ cells, the expression level of IL-1β, TNF-α, VEGF, NGF and the densities of CD31+ vascular endothelial cells and PGP9.5+ nerve fibres (p < 0.05).

CONCLUSIONS

Worsened hypertrophic synovitis, angiogenesis and sensory nerve sprouting in the synovium may play a critical role in causing worse pain sensation in PwH with not bony ankylosed haemophilic arthropathy knees than in those with bony ankylosed knees.

Systemic vascular basement membrane markers linked to synovial vascular remodeling are biomarkers of hemarthrosis in patients with hemophilia

INTRODUCTION

Interstitial, cartilage, and bone collagens have been proposed as biomarkers of joint deterioration in hemophilic arthropathy. The role of basement membrane (type IV and VIII) collagens as biomarkers of endothelial turnover in relation to acute joint bleeding is not understood.

METHODS

Thirty-one adult patients with hemophilia were studied prospectively for 3 years with musculoskeletal ultrasound/power Doppler (MSKUS/PD) during pain-free intervals and painful events for joint bleed status, synovial vascular flow, and 10 plasma markers of collagen turnover. Joint health was determined using Hemophilia Joint Health Scores and Pettersson scores. In animal studies, bleeding was induced in factor VIII-/- mice by knee joint injury. Synovial vascular remodeling was assessed using MSKUS/PD and histology. Murine plasma samples were analyzed for type IV collagen turnover markers.

RESULTS

Ninety-one patient visits were compiled. Twenty-five were due to acute painful episodes, with 16 confirmed hemarthroses. Type IV collagen turnover markers (PRO-C4 and C4M), and a type VIII collagen synthesis marker (PRO-C8), were transiently elevated during acute hemarthrosis. Hemarthrosis was accompanied by increased synovial microvascular flow (MSKUS/PD), and levels of type IV collagen markers correlated with PD signals in the joint. In factor VIII-deficient mice, plasma levels of type IV collagen turnover markers correlated negatively with synovial αSMA staining, indicating that reduced type IV collagen turnover was associated with thicker vessels.

CONCLUSIONS

Our findings suggest that basement membrane turnover markers, closely linked to synovial vascular remodeling, may be systemic biomarkers of acute hemarthrosis. Vascular instability during neovascularization may be involved in the dynamics of hemarthrosis.

Hemophilia A and B mice, but not VWF-/-mice, display bone defects in congenital development and remodeling after injury

While joint damage is the primary co-morbidity of hemophilia, osteoporosis and osteopenia are also observed. Coagulation factor VIII deficient (FVIII^−/−) mice develop an osteoporotic phenotype in the absence of induced hemarthrosis that is exacerbated two weeks after an induced joint injury. Here we have compared comprehensively the bone health of clotting factor VIII, factor IX, and Von Willebrand Factor knockout (FVIII^−/−, FIX^−/−, and VWF^−/− respectively) mice both in the absence of joint hemorrhage and following induced joint injury. We found FVIII^−/− and FIX^−/− mice, but not VWF^−/− mice, developmentally have an osteoporotic phenotype. Unilateral induced hemarthrosis causes further bone damage in both FVIII^−/− and FIX^−/− mice, but has little effect on VWF^−/− bone health, indicating that the FVIII.VWF complex is not required for normal bone remodeling in vivo. To further investigate the bone healing following hemarthrosis in hemophilia we examined a two week time course using microCT, serum chemistry, and histological analysis. Elevated ratio of osteoprotegerin (OPG)/receptor activator of nuclear factor-kappa B ligand (RANKL), increased osterix⁺ osteoblastic cells, and decreased smoothness of the cortical bone surface were evident within several days of injury, indicative of acute heterotopic mineralization along the cortical surface. This was closely followed by increased interleukin-6 (IL-6) levels, increased osteoclast numbers, and significant trabecular bone loss. Uncoupled and disorganized bone formation and resorption continued for the duration of the study resulting in significant deterioration of the joint. Further elucidation of the shared mechanisms underlying abnormal bone homeostasis in the absence of FVIII or FIX is needed to guide evidence-based approaches to the screening and treatment of the prevalent bone defects in hemophilia A and B.

Deferasirox limits cartilage damage following haemarthrosis in haemophilic mice

Joint bleeds in haemophilia result in iron-mediated synovitis and cartilage damage. It was evaluated whether deferasirox, an iron chelator, was able to limit the development of haemophilic synovitis and cartilage damage. Haemophilic mice were randomly assigned to oral treatment with deferasirox (30 mg/kg) or its vehicle (control) (30 mg/kg). Eight weeks after start of treatment, haemarthrosis was induced. After another five weeks of treatment, blood-induced synovitis and cartilage damage were determined. Treatment with deferasirox resulted in a statistically significant (p< 0.01) decrease in plasma ferritin levels as compared to the control group (823 ng/ml ± 56 and 1220 ng/ml ±114, respectively). Signs of haemophilic synovitis, as assessed by the Valentino score [range 0 (normal) – 10 (most affected)], were not different (p=0.52) when comparing the control group with the deferasirox group. However, deferasirox treatment resulted in a statistically significant (p< 0.01) reduction in cartilage damage, as assessed by the loss in Safranin O staining [range 0 (normal) – 6 (most affected)], when comparing the deferasirox group with the control group: score 2 (65.4 % vs 4.2 %), score 3 (26.9 % vs 4.2 %), score 4 (7.7 % vs 20.8 %), score 5 (0 % vs 54.2 %), and score 6 (0 % vs 16.7 %). Treatment with deferasirox limits cartilage damage following the induction of a haemarthrosis in haemophilic mice. This study demonstrates the role of iron in blood-induced cartilage damage. Moreover, these data indicate that iron chelation may be a potential prevention option to limit the development of haemophilic arthropathy.

Functional outcome of total knee arthroplasty in patients with haemophilia

INTRODUCTION

Haemophilic arthropathy (HA) is a debilitating complication of haemophilia which leads to TKA in severe cases.

AIM

We conducted a prospective study of the outcome of TKA in our haemophilia cohort to define the outcomes in this population and increase the cost effectiveness of the procedure in our developing country.

METHODS

We reviewed patients with haemophilia who underwent TKA between April 2010 and April 2014. Patients with at least 6 months of follow-up were included. Preoperative knee scores (KSS and WOMAC) and the scores of the quality of life were recorded. Radiographic indices were registered pre- and postoperatively. Any complications were recorded. The patients underwent TKA with medial parapatellar approach. We had a low threshold for quadriceps snip when exposure was difficult. As our routine we did not use suction drains postoperatively.

RESULTS

We included 83 patients (all males, 103 knees). The mean age of the patients was 35.8 years. The mean follow-up period was 45.1 months. Three patients (3.6%) had factor inhibitors. Twenty patients (24.1%) underwent bilateral simultaneous TKA. The mean admission time was 13.87 days. We had two cases of wound infection and one case of haematoma. None of our patients needed transfusion. All knee scores were significantly improved (P < 0.000).

CONCLUSION

Total knee replacement is an effective procedure in treatment of HA. Definition of standards of care for this procedure, which are tailored for resources of a developing country, can have major impact in improving outcomes while maximizing cost effectiveness of this surgery.

Development of inhibitory antibodies to therapeutic factor VIII in severe hemophilia A is associated with microsatellite polymorphisms in the HMOX1 promoter

Induction of heme oxygenase-1, a stress-inducible enzyme with anti-inflammatory activity, reduces the immunogenicity of therapeutic factor VIII in experimental hemophilia A. In humans, heme oxygenase-1 expression is modulated by polymorphisms in the promoter of the heme oxygenase-1-encoding gene (HMOX1). We investigated the relationship between polymorphisms in the HMOX1 promoter and factor VIII inhibitor development in severe hemophilia A. We performed a case-control study on 99 inhibitor-positive patients and 263 patients who did not develop inhibitors within the first 150 cumulative days of exposure to therapeutic factor VIII. Direct sequencing and DNA fragment analysis were used to study (GT)n polymorphism and single nucleotide polymorphisms located at -1135 and -413 in the promoter of HMOX1. We assessed associations between the individual allele frequencies or genotypes, and inhibitor development. Our results demonstrate that inhibitor-positive patients had a higher frequency of alleles with large (GT)n repeats (L: n≥30), which are associated with lesser heme oxygenase-1 expression (odds ratio 2.31; 95% confidence interval 1.46-3.66; P<0.001]. Six genotypes (L/L, L/M, L/S, M/M, M/S and S/S) of (GT)n repeats were identified (S: n<21; M: 21≤n<30). The genotype group including L alleles (L/L, L/M and L/S) was statistically more frequent among inhibitor-positive than inhibitor-negative patients, as compared to the other genotypes (33.3% versus 17.1%) (odds ratio 2.21, 95% confidence interval 1.30-3.76; P<0.01). To our knowledge, this is the first association identified between HMOX1 promoter polymorphism and development of anti-drug antibodies. Our study paves the way towards modulation of the endogenous anti-inflammatory machinery of hemophilia patients to reduce the risk of inhibitor development.

Management of joint bleeding in hemophilia

Hemarthrosis, the hallmark of severe hemophilia, is the major cause of serious bleeding events, disability and reduced quality of life in patients with factor VIII or factor IX deficiency. Joint bleeding is one of the greatest challenges confronting individuals treating hemophilia, and its economic impact is enormous. This article reviews the current management of hemophilic joint bleeding and discusses the potential impact of novel therapies.

Nuclear factor (NF)-κB and its associated pathways are major molecular regulators of blood-induced joint damage in a murine model of hemophilia

BACKGROUND

The present study was designed to investigate the molecular signaling events from onset of bleeding through the development of arthropathy in a murine model of hemophilia A.

METHODS AND RESULTS

A sharp-injury model of hemarthrosis was used. A global gene expression array on joint-specific RNA isolated 3 h post-injury revealed nuclear factor-kappa B (NF-κB) as the major transcription factor triggering inflammation. As a number of genes encoding the cytokines, growth factors and hypoxia regulating factors are known to be activated by NF-κB and many of these are part of the pathogenesis of various joint diseases, we reasoned that NF-κB-associated pathways may play a crucial role in blood-induced joint damage. To further understand its role, we screened NF-κB-associated pathways between 1 h to 90 days after injury. After a single articular bleed, distinct members of the NF-κB family (NF-κB1/NF-κB2/RelA/RelB) and their responsive pro-inflammatory cytokines (IL-1β/IL-6/IFNγ/TNFα) were significantly up-regulated (> 2 fold, P < 0.05) in injured vs. control joints at the various time-points analyzed (1 h/3 h/7 h/24 h). After multiple bleeds (days 30/60/75/90), there was increased expression of NF-κB-associated factors that contribute to hypoxia (HIF-1α, 3.3-6.5 fold), angiogenesis (VEGF-α, 2.5-4.4 fold) and chondrocyte damage (matrix metalloproteinase-13, 2.8-3.8 fold) in the injured joints. Micro RNAs (miR) that are known to regulate NF-κB activation (miRs-9 and 155), inflammation (miRs-16, 155 and 182) and apoptosis (miRs-19a, 155 and 186) were also differentially expressed (-4 to +13-fold) after joint bleeding, indicating that the small RNAs could modulate the arthropathy phenotype.

CONCLUSIONS

These data suggest that NF-κB-associated signaling pathways are involved in the development of hemophilic arthropathy.

RANK-RANKL-OPG in Hemophilic Arthropathy: From Clinical and Imaging Diagnosis to Histopathology

Objective.

Hemarthrosis triggers hemophilic arthropathy, involving the target joints. The histopathogenesis of blood-induced joint damage remains unclear. The triad of receptor activator of nuclear factor-κB (RANK), RANK ligand (RANKL), and osteoprotegerin (OPG; RANK-RANKL-OPG) controls bone turnover. Our aim was to evaluate RANK-RANKL-OPG expression in the synovium of hemophilic patients with severe arthropathy.

Methods.

Synovial biopsies were obtained from 18 patients with hemophilic arthropathy and 16 with osteoarthritis (OA) who were undergoing total knee replacement and synovectomy. The severity of hemophilic arthropathy was evaluated according to ultrasonography score, the World Federation of Hemophilia (WFH) orthopedic joint scale, and the radiographic Pettersson score. RANK-RANKL-OPG expression was examined by immunohistochemistry and Western blotting. Serum levels of soluble RANKL (sRANKL) and OPG from an extended group of 67 patients with hemophilic arthropathy and 30 healthy controls were measured by ELISA.

Results.

The mean ultrasonography, WFH orthopedic joint scale, and Pettersson scores in patients with hemophilic arthropathy indicated severe arthropathy. A decreased expression of OPG was found in hemophilic arthropathy synovium compared with patients with OA. RANK and RANKL immunopositivity was strong in the lining and sublining layers in hemophilic arthropathy synovial tissue. Western blotting confirmed the immunohistological findings. Serum levels of sRANKL and OPG in patients with hemophilia were lower than in healthy controls.

Conclusion.

In hemophilic arthropathy, the synovium highly expressed RANK and RANKL, whereas OPG immunopositivity decreased, suggesting an osteoclastic activation. Low tissue expression of OPG paralleled the serum levels of this protein and the severity of hemophilic arthropathy assessed by ultrasonography, Pettersson, and WFH orthopedic joint scale scores.

The aging patient with hemophilia

The prospects for many boys born with hemophilia today include a normal life expectancy and minimal to no joint disease. However, despite the availability of safe replacement clotting factor concentrates and effective antiviral treatment, the aging patient with hemophilia today faces many challenges. These include management of their hemophilia as well as the same age-related health issues as experienced in the general population. While increasing, data on the prevalence of comorbidities and their management in the hemophilia population remain limited. This review will focus on issues related to management of hemophilia and complications of cardiovascular, musculoskeletal, hepatic, and renal disease. Available research is summarized and potential approaches to management are discussed.

Factor VIII-specific B cell responses in haemophilia A patients with inhibitors

Development of inhibitory antibodies to factor VIII (FVIII) provides a major complication of replacement therapy in patients with haemophilia A. The risk of inhibitor formation is influenced by the underlying FVIII gene defect. Moreover, genetic determinants in the promoter region of IL-10 and TNFalpha have been linked to an increased risk of inhibitor development. Recent cohort-studies have provided evidence that the risk of inhibitor formation is linked to intensity of treatment. Eradication of FVIII inhibitors can be achieved by frequent infusion of high dosages of FVIII, so-called immune tolerance induction (ITI). Until now, the mechanisms involved in downmodulation of the immune response to FVIII during ITI have not been unraveled. Studies performed in an animal model for haemophilia A have suggested that elimination of FVIII-specific memory B cells by high dosages of FVIII contributes to the decline in FVIII inhibitor levels during ITI. Limited knowledge is available with respect to the development and persistence of FVIII-specific memory B cells in patients with haemophilia A. Two recent studies suggest that the frequency of peripheral FVIII-specific memory B cells in haemophilia A patients with inhibitors range from <0.01 to 0.40% of that of total IgG(+) B cells. No or very low frequencies of FVIII-specific memory B cells are observed in haemophilia A patients without inhibitors and in patients treated successfully by ITI. Possible implications of these findings are discussed in the context of currently available information on the role of antigen-specific memory B cells and long-living antibody producing plasma cells in humoral immunity.

Neoangiogenesis contributes to the development of hemophilic synovitis

Joint arthropathy secondary to recurrent hemarthroses remains a debilitating complication of hemophilia despite the use of prophylactic factor concentrates. Increased vascularity and neoangiogenesis have been implicated in the progression of musculoskeletal disorders and tumor growth. We hypothesized that de novo blood vessel formation could play a major role in the pathogenesis of hemophilic joint disease (HJD). We observed a 4-fold elevation in proangiogenic factors (vascular endothelial growth factor-A [VEGF-A], stromal cell-derived factor-1, and matrix metalloprotease-9) and proangiogenic macrophage/monocyte cells (VEGF(+)/CD68(+) and VEGFR1(+)/CD11b(+)) in the synovium and peripheral blood of HJD subjects along with significantly increased numbers of VEGFR2(+)/AC133(+) endothelial progenitor cells and CD34(+)/VEGFR1(+) hematopoietic progenitor cells. Sera from HJD subjects induced an angiogenic response in endothelial cells that was abrogated by blocking VEGF, whereas peripheral blood mononuclear cells from HJD subjects stimulated synovial cell proliferation, which was blocked by a humanized anti-VEGF antibody (bevacizumab). Human synovial cells, when incubated with HJD sera, could elicit up-regulation of HIF-1α mRNA with HIF-1α expression in the synovium of HJD subjects, implicating hypoxia in the neoangiogenesis process. Our results provide evidence of local and systemic angiogenic response in hemophilic subjects with recurrent hemarthroses suggesting a potential to develop surrogate biologic markers to identify the onset and progression of hemophilic synovitis.

Comparative study of dual energy X-ray absorptiometry and quantitative ultrasonography with the use of biochemical markers of bone turnover in boys with haemophilia

Our aim was to evaluate bone status in boys with haemophilia using dual energy X-ray absorptiometry (DXA) and quantitative ultraSonography (QUS), and in addition, to compare these two methods with the use of biochemical markers of bone turnover. Twenty-six boys with a mean decimal age of 12.08 ± 4.44 years were included in the study which included a DXA scan at lumbar spine and radial, as well as tibial QUS. Serum levels of soluble receptor activator of nuclear factor κB ligand (sRANK-L), osteoprotegerin (OPG) and osteocalcin (OC) were measured and joint evaluation was performed using the Hemophilia Joint Health Score (HJHS). With regard to the study results, only 2 of 26 patients (7.7%) had bone mineral density (BMD) Z-scores < -2, and 4 patients (15.4%) had BMD Z-scores between -1 and -2. Only one patient had radial and other two had tibial QUS Z-scores < -2. No agreement was recorded between QUS and DXA in identifying patients at risk for osteoporosis (k = 0.275, P = 0.063). Haemophiliacs had significantly higher serum levels of sRANK-L (21.04 ± 4.78 vs. 18.58 ± 2.28 ng mL(-1), P = 0.038) and of OC (5.35 ± 2.29 vs. 3.09 ± 0.61 ng mL(-1), P = 0.002) and significantly decreased levels of OPG (15.78 ± 2.53 vs. 23.79 ± 4.39 pg mL(-1), P < 0.001) compared with controls. QUS Z-scores at tibia significantly correlated with HJH Scores (r = -0.450, P = 0.040), whereas lumbar BMD Z-scores significantly correlated with body mass index Z-scores (r = 0.500, P = 0.009). More studies are warranted to identify the most accurate densitometric method for assessing bone status in haemophiliacs.

Intra-articular meniscoid folds in thoracic zygapophysial joints

STUDY DESIGN

A descriptive morphologic anatomic study was performed.

OBJECTIVE

The study aimed to investigate intra-articular meniscoids (folds) and cartilage quality in the thoracic zygapophysial joints (ZAJs), and to discuss them in the context of possible causes of thoracic back pain.

SUMMARY OF BACKGROUND DATA

The clinical relevance of the intra-articular meniscoid structures described in the cervical and lumbar spine is unclear, particularly in relation to ZAJ blockades. Corresponding data for the thoracic joints are not available.

METHODS

A total of 297 ZAJs between C7 and L1, obtained from 12 human cadavers (7 female, 5 male; mean age 81 years), were studied. The intra-articular folds were described and classified morphologically. The characteristics of the folds and their association with zygapophysial cartilage quality were investigated. Thirteen example folds were studied histologically.

RESULTS

In all, 268 intra-articular meniscoid folds were found in 183 joints. Three types were identified: type 1 (90%; mean length 3.1 mm) were thin, solid folds originating from a connective-tissue base, with multiple vessels at the joint capsule, extending between the joint surfaces. Type 2 folds (6%) were soft structures of fat and loose connective tissue including multiple vessels, located in the joint recess and not extending between the joint surfaces. The remaining folds (type 3, 4%) were circumscribed thickenings of the joint capsule. Three folds showed chronic hemorrhage, with dilated vessels at the base, and this was associated with severe cartilage lesions. In 16 folds, the base had direct tissue connection to the fat tissue of the epidural space.

CONCLUSION

This study for the first time systematically classifies intra-articular meniscoid folds in human thoracic ZAJs. These folds may represent an anatomic correlate for thoracic back pain. The chronic hemorrhage observed may be an important factor leading to arthritis.

Haemophilia imaging: a review

Haemophilia disorders are characterised by a blood coagulation anomaly leading to prolonged and excessive bleeding. Imaging provides an essential role in the investigation of both the musculoskeletal and the non-musculoskeletal complications of haemophilia. Our institution is home to a large tertiary referral centre for haemophilia treatment. Using our broad experience, we present a multi-modality pictorial review of the musculoskeletal manifestations of haemophilia, including haemophilic arthropathy, intra-muscular haemorrhage and haemophilic pseudotumour. The main imaging features of haemophilic arthropathy are described, including synovial hypertrophy, haemosiderin deposition, sub-chondral cyst formation and loss of joint space.

Increased bone resorption is implicated in the pathogenesis of bone loss in hemophiliacs: correlations with hemophilic arthropathy and HIV infection

Osteoporosis has been recently recognized as a severe comorbidity factor in hemophilia. However, its pathogenesis is still obscure. We evaluated the incidence of osteoporosis in 90 hemophilia patients and investigated possible correlations with clinical and laboratory data. Out of the 90 patients, 80 (89%) had severe hemophilia, and 35 (38.9%) were human immunodeficiency virus (HIV)-positive. Hemophilic arthropahty was assessed using World Federation of Hemophilia clinical score and Petterson radiological score. Bone mineral density of the lumbar spine (LS) and femoral neck (FN) were measured using dual-energy X-ray absortiometry. Bone turnover was evaluated by the measurement of: (1) bone resorption markers [N-terminal cross-linking telopeptide of collagen type I (NTX), C-terminal cross-linking telopeptide of collagen type I (CTX), and tartrate-resistant acid phosphatase isoform-5b (TRACP-5b)], (2) bone formation markers [bone-alkaline phosphatase (bALP) and osteocalcin], and (3) osteoclast stimulators (receptor activator of nuclear factor-kappaB ligand, osteoprotegerin, and tumor necrosis factor-alpha). Osteopenia or osteoporosis was observed in 86% and 65% of the patients in FN and LS, respectively. Osteoporosis was more common among HIV-positive patients in both FN (65.3% vs 41.6%; p = 0.007) and LS (17.86% vs 5.41%, p = 0.004). The severity of osteoporosis in FN correlated with the patients' total clinical and radiological score (p = 0.001). Hemophilia patients showed increased osteoclastic activity (significant increase of TRACP-5b, NTX, and CTX), which was not accompanied by a comparable increased bone formation (reduced osteocalcin and borderline increase of bALP). In multivariate analysis, HIV infection (p = 0.05) and total clinical score (p = 0.001) were independent risk factors for osteoporosis development. We conclude that there is a high prevalence of osteoporosis among hemophiliacs, which is related to the severity of arthropathy and is enhanced by HIV infection. We report for the first time a high bone resorption that seems not to be balanced by a comparable bone formation.

Intraarticular factor IX protein or gene replacement protects against development of hemophilic synovitis in the absence of circulating factor IX

Hemophilic bleeding into joints causes synovial and microvascular proliferation and inflammation (hemophilic synovitis) that contribute to end-stage joint degeneration (hemophilic arthropathy), the major morbidity of hemophilia. New therapies are needed for joint deterioration that progresses despite standard intravenous (IV) clotting factor replacement. To test whether factor IX within the joint space can protect joints from hemophilic synovitis, we established a hemophilia B mouse model of synovitis. Factor IX knockout (FIX(-/-)) mice received a puncture of the knee joint capsule with a needle to induce hemarthrosis; human factor IX (hFIX) was either injected through the needle into the joint space (intraarticularly) or immediately delivered IV. FIX(-/-) mice receiving intraarticular FIX protein were protected from synovitis compared with mice receiving same or greater doses of hFIX IV. Next, adeno-associated virus (AAV) gene transfer vectors expressing hFIX were injected into knee joints of FIX(-/-) mice. Joints treated with 10(10) vector genomes (vg)/joint AAV2-, AAV5-, or AAV8-hFIX or 2.5 x 10(9) vg/joint AAV5-hFIX developed significantly fewer pathologic changes 2 weeks after injury compared with the pathology of control injured contralateral hind limbs. Extravascular factor activity and joint-directed gene transfer may ameliorate hemophilic joint destruction, even in the absence of circulating FIX.

Pathogenesis of haemophilic synovitis: experimental studies on blood-induced joint damage

Hemarthrosis is a common manifestation of haemophilia, and joint arthropathy remains a frequent complication. Even though the exact mechanisms related to blood-induced joint disease have not yet been fully elucidated, it is likely that iron deposition in the synovium induces an inflammatory response that causes not only immune system activation but also stimulates angiogenesis. This process ultimately results in cartilage and bone destruction. Investigating the processes that occur in the early stages of blood-induced joint disease in humans has been very limited. Therefore, the use of haemophilic animal models is critical to augment the understanding of this phenomenon. This article discusses three cellular regulators (p53, p21 and TRAIL) induced in synovial tissue that are important for iron metabolism. A cartilage remodelling programme induced by the release of cytokines and growth factors that result in articular damage is also discussed. Full elucidation of the pathogenesis of haemophilic joint disease is required to identify new avenues for prevention and therapy.

Prophylactic treatment of haemophilia patients with inhibitors: clinical experience with recombinant factor VIIa in European Haemophilia Centres

Many patients with haemophilia develop inhibitors to factor VIII and require bypassing agents to provide haemostatic cover for limb- or life-threatening bleeding episodes. Due to the reduced risk of blood-borne pathogen transmission with recombinant products, on-demand recombinant factor VIIa (rFVIIa; NovoSeven is the treatment of choice for children with inhibitors. In haemophiliac patients without inhibitors, primary prophylaxis has been clinical practice for several years. This paper summarises 13 case histories of rFVIIa secondary prophylaxis for haemophilia patients with inhibitors. This was a retrospective survey of adult and paediatric severe haemophilia patients with inhibitors treated with rFVIIa from ten European Haemophilia Centres. There was a wide variation in administered rFVIIa dose, from 200-250 microg kg(-1) per week to 220 microg kg(-1) daily. In many cases, this was lower than the recommended on-demand dose of rFVIIa. In 12/13 cases, prophylaxis with rFVIIa considerably reduced the number of bleeding episodes compared with previous treatment. Eight/nine patients were satisfied or very satisfied with rFVIIa treatment, and in cases reporting subjective quality of life (QoL), all were improved, much improved, or significantly improved. In haemophilia patients with inhibitors, prophylaxis with rFVIIa is highly effective in reducing the number of bleeding episodes and results in good patient compliance and improved QoL. Randomised controlled trials are needed to confirm these findings. Results of a recently completed clinical trial on secondary prophylaxis with rFVIIa in frequently bleeding haemophilia patients with inhibitors are expected in late 2006.

Restoring hemostatic thrombin generation at the time of cutaneous wounding does not normalize healing in hemophilia B

BACKGROUND

We recently reported that wound healing is abnormal in hemophilia B (HB) mice [1]. The wounds show abnormal histology: s.c. hematoma formation; delayed re-epithelialization; delayed macrophage influx; and an increase in wound site angiogenesis.

OBJECTIVE

To test the hypothesis that restoring a hemostatic level of thrombin generation at the time of wounding would allow formation of an adequate platelet/fibrin plug and correct abnormalities of wound healing in HB.

METHODS

We placed a 3-mm cutaneous wound on the back of each HB or wild-type (WT) mouse. Some HB mice were treated just prior to wounding with either human factor IX (FIX) or FVIIa in a dose sufficient to normalize bleeding in a tail bleed model.

RESULTS

The average wound size over time in treated HB animals was intermediate between those in WT and untreated HB mice. However, the time to complete skin closure was not improved by treatment. Hematoma formation was decreased and macrophage influx began earlier in treated than in untreated HB animals. However, treated HB mice had evidence of ongoing low-level bleeding near the wound site, even after closure of the skin defect. Treatment also did not normalize the increased angiogenesis observed in HB mice.

CONCLUSIONS

Restoring initial hemostasis can modulate some of the parameters of wound healing. However, an extended period of adequate hemostatic function is necessary to achieve normal healing, probably because the risk of hemorrhage is increased by vascular remodeling and angiogenesis during the healing process.